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Rosli NA, Al-Maleki AR, Loke MF, Tay ST, Rofiee MS, Teh LK, Salleh MZ, Vadivelu J. Exposure of Helicobacter pylori to clarithromycin in vitro resulting in the development of resistance and triggers metabolic reprogramming associated with virulence and pathogenicity. PLoS One 2024; 19:e0298434. [PMID: 38446753 PMCID: PMC10917248 DOI: 10.1371/journal.pone.0298434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 01/23/2024] [Indexed: 03/08/2024] Open
Abstract
In H. pylori infection, antibiotic-resistance is one of the most common causes of treatment failure. Bacterial metabolic activities, such as energy production, bacterial growth, cell wall construction, and cell-cell communication, all play important roles in antimicrobial resistance mechanisms. Identification of microbial metabolites may result in the discovery of novel antimicrobial therapeutic targets and treatments. The purpose of this work is to assess H. pylori metabolomic reprogramming in order to reveal the underlying mechanisms associated with the development of clarithromycin resistance. Previously, four H. pylori isolates were induced to become resistant to clarithromycin in vitro by incrementally increasing the concentrations of clarithromycin. Bacterial metabolites were extracted using the Bligh and Dyer technique and analyzed using metabolomic fingerprinting based on Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (LC-Q-ToF-MS). The data was processed and analyzed using the MassHunter Qualitative Analysis and Mass Profiler Professional software. In parental sensitivity (S), breakpoint isolates (B), and induced resistance isolates (R) H. pylori isolates, 982 metabolites were found. Furthermore, based on accurate mass, isotope ratios, abundances, and spacing, 292 metabolites matched the metabolites in the Agilent METLIN precise Mass-Personal Metabolite Database and Library (AM-PCDL). Several metabolites associated with bacterial virulence, pathogenicity, survival, and proliferation (L-leucine, Pyridoxone [Vitamine B6], D-Mannitol, Sphingolipids, Indoleacrylic acid, Dulcitol, and D-Proline) were found to be elevated in generated resistant H. pylori isolates when compared to parental sensitive isolates. The elevated metabolites could be part of antibiotics resistance mechanisms. Understanding the fundamental metabolome changes in the course of progressing from clarithromycin-sensitive to breakpoint to resistant in H. pylori clinical isolates may be a promising strategy for discovering novel alternatives therapeutic targets.
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Affiliation(s)
- Naim Asyraf Rosli
- Faculty of Medicine, Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Anis Rageh Al-Maleki
- Faculty of Medicine, Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
- Faculty of Medicine and Health Sciences, Department of Medical Microbiology, Sana’a University, Sana’a, Yemen
| | - Mun Fai Loke
- Camtech Biomedical Pte Ltd, Singapore, Singapore
| | - Sun Tee Tay
- Faculty of Medicine, Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Mohd Salleh Rofiee
- Integrative Pharmacogenomics Institute (iPROMISE), Universiti Teknologi MARA, Selangor, Malaysia
| | - Lay Kek Teh
- Integrative Pharmacogenomics Institute (iPROMISE), Universiti Teknologi MARA, Selangor, Malaysia
| | - Mohd Zaki Salleh
- Integrative Pharmacogenomics Institute (iPROMISE), Universiti Teknologi MARA, Selangor, Malaysia
| | - Jamuna Vadivelu
- Faculty of Medicine, Medical Education Research and Development Unit (MERDU), Universiti Malaya, Kuala Lumpur, Malaysia
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Zulpa AK, Muttiah B, Vellasamy KM, Mariappan V, Vadivelu J. Dentatin triggers ROS-mediated apoptosis, G0/G1 cell cycle arrest and release of Th1-related cytokines in colorectal carcinoma cells. Journal of Taibah University for Science 2023. [DOI: 10.1080/16583655.2023.2194231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Affiliation(s)
- Ahmad Khusairy Zulpa
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Barathan Muttiah
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Kumutha Malar Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Vanitha Mariappan
- Center of Toxicology and Health Risk Studies (CORE), Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
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Barathan M, Shivashekaregowda NKH, Hoong SM, Vellasamy KM, Vadivelu J. Anticancer effect of aromatic isoniazid derivatives in human gastric adenocarcinoma cells. Toxicol Appl Pharmacol 2023; 481:116767. [PMID: 38007073 DOI: 10.1016/j.taap.2023.116767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/28/2023] [Accepted: 11/17/2023] [Indexed: 11/27/2023]
Abstract
Current treatments for stomach cancer are often effective in curing cancer. However, these treatments can also have significant side effects, and they may not be effective in all cases. Hence synthetic compounds exhibit promise as potential agents for cancer treatment. In a previous study, we identified (E)-N'- (2,3,4-trihydroxybenzylidene) isonicotinohydrazide (ITHB4) as a novel antimycobacterial derivative of isoniazid with cytotoxic effects on the MCF-7 breast cancer cell line. This led us to investigate the potential anti-cancer properties of ITHB4 against adenocarcinoma gastric (AGS) cell line. The cytotoxic effect of ITHB4 has been determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and further confirmed for anticancer properties by means of apoptosis, reactive oxygen species (ROS), nuclear fragmentation, lactate dehydrogenase (LDH), caspases, cytokines and morphological including phenotypic changes of cells assay. The ITHB4 demonstrated a lower IC50 in inhibiting growth of AGS cells at 24 h compared to 48 and 72 h. ITHB4 has also shown no toxicity human immune cells. Treatment of ITHB4 against AGS for 24 h eventually lead to formation of early apoptotic AGS cells, reduced mitochondrial membrane potential, nuclear condensation, and nuclear fragmentation lastly increased in ROS levels together with the release of LDH, and secretion of caspases. The altered cytokine profile in ITHB4 treated AGS hints at the possibility that ITHB4 may possess anti-tumor and anti-inflammatory properties. Our results in this study demonstrate that ITHB4 has almost similar chemotherapeutic properties against gastric adenocarcinoma cells compared to breast cancer cell. This is suggesting that the anticancer capabilities of this compound should be in vivo and clinically assessed.
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Affiliation(s)
- Muttiah Barathan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia.
| | | | - See Mee Hoong
- Department of Surgery, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia.
| | - Kumutha Malar Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia.
| | - Jamuna Vadivelu
- MERDU, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia.
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Rosli NA, Al-Maleki AR, Loke MF, Chua EG, Alhoot MA, Vadivelu J. Polymorphism of virulence genes and biofilm associated with in vitro induced resistance to clarithromycin in Helicobacter pylori. Gut Pathog 2023; 15:52. [PMID: 37898785 PMCID: PMC10613384 DOI: 10.1186/s13099-023-00579-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/19/2023] [Indexed: 10/30/2023] Open
Abstract
BACKGROUND Clarithromycin-containing triple therapy is commonly used to treat Helicobacter pylori infections. Clarithromycin resistance is the leading cause of H. pylori treatment failure. Understanding the specific mutations that occur in H. pylori strains that have evolved antibiotic resistance can help create a more effective and individualised antibiotic treatment plan. However, little is understood about the genetic reprogramming linked to clarithromycin exposure and the emergence of antibiotic resistance in H. pylori. Therefore, this study aims to identify compensatory mutations and biofilm formation associated with the development of clarithromycin resistance in H. pylori. Clarithromycin-sensitive H. pylori clinical isolates were induced to develop clarithromycin resistance through in vitro exposure to incrementally increasing concentration of the antibiotic. The genomes of the origin sensitive isolates (S), isogenic breakpoint (B), and resistant isolates (R) were sequenced. Single nucleotide variations (SNVs), and insertions or deletions (InDels) associated with the development of clarithromycin resistance were identified. Growth and biofilm production were also assessed. RESULTS The S isolates with A2143G mutation in the 23S rRNA gene were successfully induced to be resistant. According to the data, antibiotic exposure may alter the expression of certain genes, including those that code for the Cag4/Cag protein, the vacuolating cytotoxin domain-containing protein, the sel1 repeat family protein, and the rsmh gene, which may increase the risk of developing and enhances virulence in H. pylori. Enhanced biofilm formation was detected among R isolates compared to B and S isolates. Furthermore, high polymorphism was also detected among the genes associated with biofilm production. CONCLUSIONS Therefore, this study suggests that H. pylori may acquire virulence factors while also developing antibiotic resistance due to clarithromycin exposure.
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Affiliation(s)
- Naim Asyraf Rosli
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Anis Rageh Al-Maleki
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia.
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen.
| | - Mun Fai Loke
- Camtech Biomedical Pte Ltd, Singapore, Singapore
| | - Eng Guan Chua
- School of Biomedical Sciences, Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Perth, WA, Australia
| | - Mohammed Abdelfatah Alhoot
- Faculty of Pharmacy, Airlangga University, Surabaya, 60155, Indonesia
- School of Graduate Studies, Management & Science University, Shah Alam, Selangor, Malaysia
| | - Jamuna Vadivelu
- Medical Education Research and Development Unit, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
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Zulpa AK, Barathan M, Iyadorai T, Mariappan V, Vadivelu J, Teh CSJ, Vellasamy KM. Selective pks+ Escherichia coli strains induce cell cycle arrest and apoptosis in colon cancer cell line. World J Microbiol Biotechnol 2023; 39:333. [PMID: 37801157 DOI: 10.1007/s11274-023-03767-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/15/2023] [Indexed: 10/07/2023]
Abstract
pks+ Escherichia coli (E. coli) triggers genomic instability in normal colon cells which leads to colorectal cancer (CRC) tumorigenesis. Previously, we reported a significant presentation of pks+ E. coli strains in CRC patients' biopsies as compared to healthy cohorts. In this work, using an in vitro infection model, we further explored the ability of these strains in modulating cell cycle arrest and activation of apoptotic mediators in both primary colon epithelial cells (PCE) and CRC cells (HCT-116). Sixteen strains, of which eight tumours and the matching non-malignant tissues, respectively, from eight pks+ E. coli CRC patients were subjected to BrDU staining and cell cycle analysis via flow cytometry, while a subset of these strains underwent analysis of apoptotic mediators including caspase proteins, cellular reactive oxygen species (cROS) and mitochondrial membrane potential (MMP) via spectrophotometry as well as proinflammatory cytokines via flow cytometry. Data revealed that all strains exerted S-phase cell cycle blockade in both cells and G2/M phase in PCE cells only. Moreover, more significant upregulation of Caspase 9, cROS, proinflammatory cytokines and prominent downregulation of MMP were detected in HCT-116 cells indicating the potential role of pks related bacterial toxin as anticancer agent as compared to PCE cells which undergo cellular senescence leading to cell death without apparent upregulation of apoptotic mediators. These findings suggest the existence of discrepancies underlying the mechanism of action of pks+ E. coli on both cancer and normal cell lines. This work propounds the rationale to further understand the mechanism underlying pks+ E. coli-mediated CRC tumorigenesis and cancer killing.
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Affiliation(s)
- A K Zulpa
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - M Barathan
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - T Iyadorai
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - V Mariappan
- Center of Toxicology and Health Risk Studies (CORE), Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - J Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia.
| | - C S J Teh
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - K M Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
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Barathan M, Vellasamy KM, Mariappan V, Venkatraman G, Vadivelu J. Naturally Occurring Phytochemicals to Target Breast Cancer Cell Signaling. Appl Biochem Biotechnol 2023:10.1007/s12010-023-04734-0. [PMID: 37773580 DOI: 10.1007/s12010-023-04734-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2023] [Indexed: 10/01/2023]
Abstract
Almost 70% of clinically used antineoplastic drugs are originated from natural products such as plants, marine organism, and microorganisms and some of them are also structurally modified natural products. The naturally occurring drugs may specifically act as inducers of selective cytotoxicity, anti-metastatic, anti-mutagenic, anti-angiogenesis, antioxidant accelerators, apoptosis inducers, autophagy inducers, and cell cycle inhibitors in cancer therapy. Precisely, several reports have demonstrated the involvement of naturally occurring anti-breast cancer drugs in regulating the expression of oncogenic and tumor suppressors associated with carcinogen metabolism and signaling pathways. Anticancer therapies based on nanotechnology have the potential to improve patient outcomes through targeted therapy, improved drug delivery, and combination therapies. This paper has reviewed the current treatment for breast cancer and the potential disadvantages of those therapies, besides the various mechanism used by naturally occurring phytochemicals to induce apoptosis in different types of breast cancer. Along with this, the contribution of nanotechnology in improving the effectiveness of anticancer drugs was also reviewed. With the development of sciences and technologies, phytochemicals derived from natural products are continuously discovered; however, the search for novel natural products as chemoprevention drugs is still ongoing, especially for the advanced stage of breast cancer. Continued research and development in this field hold great promise for advancing cancer care and improving patient outcomes.
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Affiliation(s)
- Muttiah Barathan
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Lembah Pantai, 50603, Kuala Lumpur, Malaysia.
| | - Kumutha Malar Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Lembah Pantai, 50603, Kuala Lumpur, Malaysia
| | - Vanitha Mariappan
- Center of Toxicology and Health Risk Studies (CORE), Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Aziz, 50300, Kuala Lumpur, Malaysia
| | - Gopinath Venkatraman
- Universiti Malaya Centre for Proteomics Research, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
- Department of Biochemistry, Saveetha Dental College, Saveetha Institute of Medical & Technical Sciences, Saveetha University, Chennai 600 077, India
| | - Jamuna Vadivelu
- MERDU, Faculty of Medicine, Universiti Malaya, Lembah Pantai, 50603, Kuala Lumpur, Malaysia.
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Maniam L, Vellasamy KM, Ong TA, Teh CSJ, Jabar KA, Mariappan V, Narayanan V, Vadivelu J, Pallath V. Genotypic characteristics of Uropathogenic Escherichia coli isolated from complicated urinary tract infection (cUTI) and asymptomatic bacteriuria-a relational analysis. PeerJ 2023; 11:e15305. [PMID: 37361034 PMCID: PMC10289082 DOI: 10.7717/peerj.15305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 04/06/2023] [Indexed: 06/28/2023] Open
Abstract
Background Uropathogenic Escherichia coli (UPEC) is the predominant agent causing various categories of complicated urinary tract infections (cUTI). Although existing data reveals that UPEC harboured numerous virulence determinants to aid its survival in the urinary tract, the reason behind the occurrence of differences in the clinical severity of uninary tract infections (UTI) demonstrated by the UPEC infection is poorly understood. Therefore, the present study aims to determine the distribution of virulence determinants and antimicrobial resistance among different phylogroups of UPEC isolated from various clinical categories of cUTI and asymptomatic bacteriuria (ASB) E. coli isolates. The study will also attempt a relational analysis of the genotypic characteristics of cUTI UPEC and ASB E. coli isolates. Methods A total of 141 UPEC isolates from cUTI and 160 ASB E. coli isolates were obtained from Universiti Malaya Medical Centre (UMMC). Phylogrouping and the occurrence of virulence genes were investigated using polymerase chain reaction (PCR). Antimicrobial susceptibility of the isolates to different classes of antibiotics was determined using the Kirby Bauer Disc Diffusion method. Results The cUTI isolates were distributed differentially among both Extraintestinal Pathogenic E. coli (ExPEC) and non-ExPEC phylogroups. Phylogroup B2 isolates were observed to possess the highest average aggregative virulence score (7.17), a probable representation of the capability to cause severe disease. Approximately 50% of the cUTI isolates tested in this study were multidrug resistant against common antibiotics used to treat UTI. Analysis of the occurrence of virulence genes among different cUTI categories demonstrated that UPEC isolates of pyelonephritis and urosepsis were highly virulent and had the highest average aggregative virulence scores of 7.80 and 6.89 respectively, compared to other clinical categories. Relational analysis of the occurrence of phylogroups and virulence determinants of UPEC and ASB E. coli isolates showed that 46.1% of UPEC and 34.3% of ASB E. coli from both categories were distributed in phylogroup B2 and had the highest average aggregative virulence score of 7.17 and 5.37, respectively. The data suggest that UPEC isolates which carry virulence genes from all four virulence genes groups studied (adhesions, iron uptake systems, toxins and capsule synthesis) and isolates from phylogroup B2 specifically could predispose to severe UTI involving the upper urinary tract. Therefore, specific analysis of the genotypic characteristics of UPEC could be further explored by incorporating the combination of virulence genes as a prognostic marker for predicting disease severity, in an attempt to propose a more evidence driven treatment decision-making for all UTI patients. This will go a long way in enhancing favourable therapeutic outcomes and reducing the antimicrobial resistance burden among UTI patients.
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Affiliation(s)
- Lalitha Maniam
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Kumutha Malar Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Teng Aik Ong
- Department of Surgery, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Cindy Shuan Ju Teh
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Kartini Abdul Jabar
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Vanitha Mariappan
- Centre of Toxicology and Health Risk Studies (CORE), Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Vallikkannu Narayanan
- Department of Obstetrics and Gynaecology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Vinod Pallath
- Medical Education Research and Development Unit (MERDU), Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
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Khairul Anhar Holder NA, Pallath V, Vadivelu J, Foong CC. Correction: Using document phenomenology to investigate academic failure among year 1 undergraduate Malaysian medical students. BMC Med Educ 2023; 23:407. [PMID: 37277806 DOI: 10.1186/s12909-023-04400-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Affiliation(s)
| | - Vinod Pallath
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, Universiti Malaya, Kuala Lumpur, 50603, Malaysia
| | - Jamuna Vadivelu
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, Universiti Malaya, Kuala Lumpur, 50603, Malaysia
| | - Chan Choong Foong
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, Universiti Malaya, Kuala Lumpur, 50603, Malaysia.
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Khairul Anhar Holder NA, Pallath V, Vadivelu J, Foong CC. Using document phenomenology to investigate academic failure among year 1 undergraduate Malaysian medical students. BMC Med Educ 2023; 23:310. [PMID: 37147649 PMCID: PMC10161666 DOI: 10.1186/s12909-023-04285-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 04/20/2023] [Indexed: 05/07/2023]
Abstract
BACKGROUND Academic failure is common among medical schools worldwide. However, the process behind this failure itself is underexplored. A deeper understanding of this phenomenon may avert the vicious cycle of academic failure. Hence, this study investigated the process of academic failure among medical students in Year 1. METHODS This study employed a document phenomenological approach, which is a systematic process to examine documents, interpret them to attain understanding, and develop empirical knowledge of the phenomenon studied. Using document analysis, interview transcripts and reflective essays of 16 Year 1 medical students who experienced academic failure were analysed. Based on this analysis, codes were developed and further reduced into categories and themes. Thirty categories in eight themes were linked to make sense of the series of events leading to academic failure. RESULTS One or more critical incidents commenced during the academic year, which led to possible resulting events. The students had poor attitudes, ineffective learning methods, health problems or stress. Students progressed to mid-year assessments and reacted differently to their results in the assessments. Afterwards, the students tried different types of attempts, and they still failed the end-of-year assessments. The general process of academic failure is illustrated in a diagram describing chronological events. CONCLUSION Academic failure may be explained by a series of events (and consequences) of what students experience and do and how they respond to their experiences. Preventing a preceding event may prevent students from suffering these consequences.
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Affiliation(s)
| | - Vinod Pallath
- ¹Medical Education and Research Development Unit (MERDU), Faculty of Medicine, Universiti Malaya, Kuala Lumpur, 50603, Malaysia
| | - Jamuna Vadivelu
- ¹Medical Education and Research Development Unit (MERDU), Faculty of Medicine, Universiti Malaya, Kuala Lumpur, 50603, Malaysia
| | - Chan Choong Foong
- ¹Medical Education and Research Development Unit (MERDU), Faculty of Medicine, Universiti Malaya, Kuala Lumpur, 50603, Malaysia.
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Mayandi V, Kang WT, Ting DSJ, Goh ETL, Lynn MN, Aung TT, Vadivelu J, Barathi VA, Chan ASY, Lakshminarayanan R. Propranolol Ameliorates the Antifungal Activity of Azoles in Invasive Candidiasis. Pharmaceutics 2023; 15:pharmaceutics15041044. [PMID: 37111530 PMCID: PMC10144167 DOI: 10.3390/pharmaceutics15041044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/10/2023] [Accepted: 03/18/2023] [Indexed: 04/29/2023] Open
Abstract
The effectiveness of current antifungal therapies is hampered by the emergence of drug resistance strains, highlighting an urgent need for new alternatives such as adjuvant antifungal treatments. This study aims to examine the synergism between propranolol and antifungal drugs, based on the premise that propranolol is known to inhibit fungal hyphae. In vitro studies demonstrate that propranolol potentiates the antifungal activity of azoles and that the effect is more pronounced for propranolol-itraconazole combination. Using an in vivo murine systemic candidemia model, we show that propranolol-itraconazole combination treatment resulted in a lower rate of body weight loss, decreased kidney fungal bioburden and renal inflammation when compared to propranolol and azole treatment alone or untreated control. Altogether, our findings suggest that propranolol increases the efficacy of azoles against C. albicans, offering a new therapeutic strategy against invasive fungal infections.
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Affiliation(s)
- Venkatesh Mayandi
- Ocular Infections and Anti-Microbials Research, Singapore Eye Research Institute, Singapore 169856, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Wen-Tyng Kang
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia
| | - Darren Shu Jeng Ting
- Ocular Infections and Anti-Microbials Research, Singapore Eye Research Institute, Singapore 169856, Singapore
- Birmingham and Midland Eye Centre, Birmingham B18 7QH, UK
- Academic Unit of Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2TT, UK
| | - Eunice Tze Leng Goh
- Ocular Infections and Anti-Microbials Research, Singapore Eye Research Institute, Singapore 169856, Singapore
| | - Myoe Naing Lynn
- Translational Ophthalmic Pathology-Immunology Platform, Singapore Eye Research Institute, Singapore 169856, Singapore
| | - Thet Tun Aung
- Ocular Infections and Anti-Microbials Research, Singapore Eye Research Institute, Singapore 169856, Singapore
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia
| | - Veluchamy Amutha Barathi
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute, Singapore 169856, Singapore
| | - Anita Sook Yee Chan
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute, Singapore 169856, Singapore
- Singapore National Eye Centre, Singapore 169856, Singapore
| | - Rajamani Lakshminarayanan
- Ocular Infections and Anti-Microbials Research, Singapore Eye Research Institute, Singapore 169856, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
- Department of Pharmacy, National University of Singapore, Singapore 117559, Singapore
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Foong CC, Bashir Ghouse NL, Lye AJ, Pallath V, Hong WH, Vadivelu J. Differences between high- and low-achieving pre-clinical medical students: a qualitative instrumental case study from a theory of action perspective. Ann Med 2022; 54:195-210. [PMID: 35019800 PMCID: PMC8757602 DOI: 10.1080/07853890.2021.1967440] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Poor academic performance and failure can cause undesired effects for students, schools, and society. Understanding why some students fail while their peers succeed is important to enhance student performance. Therefore, this study explores the differences in the learning process between high- and low-achieving pre-clinical medical students from a theory of action perspective. METHODS This study employed a qualitative instrumental case study design intended to compare two groups of students-high-achieving students (n = 14) and low-achieving students (n = 5), enrolled in pre-clinical medical studies at the Universiti Malaya, Malaysia. Data were collected through reflective journals and semi-structured interviews. Regarding journaling, participants were required to recall their learning experiences of the previous academic year. Two analysts coded the data and then compared the codes of high- and low-achieving students. The third analyst reviewed the codes. Themes were identified iteratively, working towards comparing the learning processes of high- and low-achieving students. RESULTS Data analysis revealed four themes-motivation and expectation, study methods, self-management, and flexibility of mindset. First, high-achieving students were more motivated and had higher academic expectations than low-achieving students. Second, high-achieving students adopted study planning and deep learning approaches, whereas low-achieving students adopted superficial learning approaches. Third, in contrast to low-achieving students, high-achieving students exhibited better time management and studied consistently. Finally, high-achieving students proactively sought external support and made changes to overcome challenges. In contrast, low-achieving students were less resilient and tended to avoid challenges. CONCLUSION Based on the theory of action, high-achieving students utilize positive governing variables, whereas low-achieving students are driven by negative governing variables. Hence, governing variable-based remediation is needed to help low-achieving students interrogate the motives behind their actions and realign positive governing variables, actions, and intended outcomes.Key MessagesThis study found four themes describing the differences between high- and low-achieving pre-clinical medical students: motivation and expectation, study methods, self-management, and flexibility of mindset.Based on the theory of action approach, high-achieving pre-clinical medical students are fundamentally different from their low-achieving peers in terms of their governing variables, with the positive governing variables likely to have guided them to act in a manner beneficial to and facilitating desirable academic performance.Governing variable-based remediation may help students interrogate the motives of their actions.
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Affiliation(s)
- Chan Choong Foong
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Nur Liyana Bashir Ghouse
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - An Jie Lye
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Vinod Pallath
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Wei-Han Hong
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
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12
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Drewes JL, Queen J, Domingue JC, Wensel CR, Cai Y, Wanyiri J, Roslani AC, Vadivelu J, Johnson CH, Sears CL. Abstract 3052: Fusobacterial-dominant colorectal cancer biofilms are associated with high levels of the polyamine N1,N12-diacetylspermine. Cancer Res 2022. [DOI: 10.1158/1538-7445.am2022-3052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Mucus-invasive colonic bacterial biofilms are dense, polymicrobial communities that are in direct contact with the epithelium. Prior data from our group has demonstrated that these invasive biofilms are prevalent in colorectal cancer, are directly tumorigenic in germ-free and specific pathogen-free ApcMin/+ mouse models, and are associated with enrichment of the polyamine N1,N12-diactylspermine (DAS) in patient samples. However, whether the composition of these biofilms impacts their pro-tumorigenic behavior and/or metabolism is presently unknown.
Methods: Carnoy’s-fixed CRC resections from 115 patients from the University of Malaya in Malaysia were stained with the all-bacterial EUB338 probe and screened for mucus-invasive biofilms (BF). All BF+ samples were subsequently stained with oligonucleotide probes targeting Bacteroidetes, Fusobacteria, Lachnospiraceae, and γ/β-Proteobacteria. Imaging was performed on a Zeiss780 confocal microscope with linear unmixing. Untargeted metabolomics was performed on 5-10 samples of each biofilm type using a Waters UPLC Xevo GS-XS quadrupole time-of-flight (QTOF) mass spectrometer. Five Fusobacterium nucleatum (Fn) strains derived from CRC cohorts were singly gavaged into germ-free ApcMin/+ mice and colons were harvested for tumors 11 wk later.
Results: Seventy-nine of 115 Malaysian tumors (69%) were BF+ using EUB338 staining. As with our prior US CRC cohort, BFs were more prevalent on the tumors proximal to the hepatic flexure (35/39, 90%) vs. those that were distal (44/76, 58%) (Chi-square p < 0.001). Of the BF+ tumors (BF+T), 55% were polymicrobial (predominantly Bacteroidetes/Lachnospiraceae), 40% were polymicrobial with fusobacterial blooms, and 5% were Proteobacteria dominant. Untargeted metabolomics of BF- healthy biopsies, BF-T, and BF+T with various BF composition subtypes revealed a gradient in levels of the polyamine DAS, with BF+T with fusobacterial blooms having the highest levels (p = 0.055 vs. Proteo-dominant BF+T, p = 0.043 vs. polymicrobial BF+T, p = 0.015 vs. BF-T, p < 0.001 vs. BF- healthy biopsies), suggesting that fusobacteria may drive proliferation and polyamine production in CRC tissues. However, inoculation of 5 different CRC-derived Fn strains including a strain isolated from a Malaysia CRC patient did not promote tumorigenesis in germ-free ApcMin/+ mice.
Conclusions: Fusobacterial-dominant biofilms are prevalent in a Malaysian CRC cohort and are associated with high levels of the polyamine N1,N12-diacetylspermine. However, F. nucleatum strains were not tumorigenic in germ-free ApcMin/+ mice, suggesting that the association between Fn, DAS, and tumorigenesis may require other bacteria in order to confer a procarcinogenic state.
Citation Format: Julia L. Drewes, Jessica Queen, Jada C. Domingue, Caroline R. Wensel, Yuping Cai, Jane Wanyiri, April C. Roslani, Jamuna Vadivelu, Caroline H. Johnson, Cynthia L. Sears. Fusobacterial-dominant colorectal cancer biofilms are associated with high levels of the polyamine N1,N12-diacetylspermine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3052.
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Affiliation(s)
| | - Jessica Queen
- 1Johns Hopkins University School of Medicine, Baltimore, MD
| | | | | | - Yuping Cai
- 2Yale School of Public Health, New Haven, CT
| | - Jane Wanyiri
- 1Johns Hopkins University School of Medicine, Baltimore, MD
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13
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Maniam L, Vellasamy KM, Jindal HM, Narayanan V, Danaee M, Vadivelu J, Pallath V. Demonstrating the utility of Escherichia coli asymptomatic bacteriuria isolates’ virulence profile towards diagnosis and management—A preliminary analysis. PLoS One 2022; 17:e0267296. [PMID: 35522610 PMCID: PMC9075641 DOI: 10.1371/journal.pone.0267296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 04/06/2022] [Indexed: 11/19/2022] Open
Abstract
Asymptomatic bacteriuria (ASB) caused by Escherichia coli (E. coli) is a significant condition associated with pregnancy and is considered as prognostic for the development of symptomatic urinary tract infection (UTI). However, treating all ASB increases the use of antibiotics and leads to the development of multidrug resistance (MDR). Therefore, this study aimed to identify the distribution of UPEC associated virulence genes and antibiotic susceptibility among phylogroups of E. coli isolated from ASB in pregnancy. Moreover, the gene expression of selected virulence genes was also compared among two E. coli isolates (with different pathogenic potential) to determine its pathogenicity. One hundred and sixty E. coli isolates from midstream urine samples of pregnant women with ASB were subjected to PCR-based detection for its phylogroups and virulence genes. The antibiotic susceptibility of isolated strains was determined by the disc diffusion method. Expression of the virulence genes were determined through microarray analysis and quantitative Real-Time PCR. The prevalence of ASB in this study was 16.1%. Within ASB isolates, the occurrence of phylogroup B2 was the highest, and isolates from this group harboured most of the virulence genes studied. Overall, the most identified virulence genes among all phylogroups in descending order were fimH, chuA, kpsMTII, usp, fyuA, hlyA, iroN, cnf, papC, sfa, ompT, and sat. In this study, higher resistance to antibiotics was observed for ampicillin (77.5%), amoxicillin-clavulanate (54.4%), trimethoprim-sulfamethoxazole (46.9%) and amikacin (43.8%) compared to the other tested antibiotics and 51.9% of the tested isolates were MDR. Furthermore, hierarchical clustering and gene expression analysis demonstrated extreme polarization of pathogenic potential of E. coli causing ASB in pregnancy necessitating the need for bacterial isolate focused approach towards treatment of ASB.
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Affiliation(s)
- Lalitha Maniam
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kumutha Malar Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Hassan Mahmood Jindal
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Vallikannu Narayanan
- Department of Obstetrics and Gynaecology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Mahmoud Danaee
- Department of Social and Preventive Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Vinod Pallath
- Medical Education Research and Development Unit (MERDU), Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- * E-mail:
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Ganesh P, Veena K, Senthil R, Iswamy K, Ponmalar EM, Mariappan V, Girija ASS, Vadivelu J, Nagarajan S, Challabathula D, Shankar EM. Biofilm-Associated Agr and Sar Quorum Sensing Systems of Staphylococcus aureus Are Inhibited by 3-Hydroxybenzoic Acid Derived from Illicium verum. ACS Omega 2022; 7:14653-14665. [PMID: 35557687 PMCID: PMC9088959 DOI: 10.1021/acsomega.1c07178] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 03/31/2022] [Indexed: 05/10/2023]
Abstract
Biofilm-producing Staphylococcus aureus (S. aureus) is less sensitive to conventional antibiotics than free-living planktonic cells. Here, we evaluated the antibiofilm activity of Illicium verum (I. verum) and one of its constituent compounds 3-hydroxybenzoic acid (3-HBA) against multi-drug-resistant S. aureus. We performed gas chromatography-mass spectroscopy (GC-MS) to identify the major constituents in the methanolic extract of I. verum. Ligand-receptor interactions were studied by molecular docking, and in vitro investigations were performed using crystal violet assay, spreading assay, hemolysis, proteolytic activity, and growth curve analysis. The methanolic extract of I. verum inhibited S. aureus at 4.8 mg/mL, and GC-MS analysis revealed anethole, m-methoxybenzaldehyde, and 3-HBA as the major constituents. Molecular docking attributed the antibiofilm activity to an active ligand present in 3-HBA, which strongly interacted with the active site residues of AgrA and SarA of S. aureus. At a subinhibitory concentration of 2.4 mg/mL, the extract showed biofilm inhibition. Similarly, 3-HBA inhibited biofilm activity at 25 μg/mL (90.34%), 12.5 μg/mL (77.21%), and 6.25 μg/mL (62.69%) concentrations. Marked attrition in bacterial spreading was observed at 2.4 mg/mL (crude extract) and 25 μg/mL (3-HBA) concentrations. The methanol extract of I. verum and 3-HBA markedly inhibited β-hemolytic and proteolytic activities of S. aureus. At the lowest concentration, the I. verum extract (2.4 mg/mL) and 3-HBA (25 μg/mL) did not inhibit bacterial growth. Optical microscopy and SEM analysis confirmed that I. verum and 3-HBA significantly reduced biofilm dispersion without disturbing bacterial growth. Together, we found that the antibiofilm activity of I. verum and 3-HBA strongly targeted the Agr and Sar systems of S. aureus.
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Affiliation(s)
- Pitchaipillai
Sankar Ganesh
- Department
of Microbiology, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Velappanchavadi, PH Road, Chennai 600077, Tamilnadu, India
| | - Krishnamurthy Veena
- Infection
Biology, Department of Life Sciences, Central
University of Tamil Nadu, Neelakudi, Tiruvarur 610005, Tamilnadu, India
| | - Renganathan Senthil
- Department
of Bioinformatics, Marudupandiyar College, Vallam, Thanjavur 613403, Tamilnadu, India
| | - Koneti Iswamy
- Infection
Biology, Department of Life Sciences, Central
University of Tamil Nadu, Neelakudi, Tiruvarur 610005, Tamilnadu, India
| | - Esaki Muthu Ponmalar
- Sri
Sairam Siddha Medical College and Research Centre, West Tambaram, Chennai 600044, Tamilnadu, India
| | - Vanitha Mariappan
- Center
for Toxicology and Health Risk Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
| | - A. S. Smiline Girija
- Department
of Microbiology, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Velappanchavadi, PH Road, Chennai 600077, Tamilnadu, India
| | - Jamuna Vadivelu
- Department
of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia
| | - Samuthira Nagarajan
- Department
of Chemistry, Central University of Tamil
Nadu, Neelakudi, Tiruvarur 610005, Tamil Nadu, India
| | - Dinakar Challabathula
- Department
of Life Sciences, Central University of
Tamil Nadu, Neelakudi, Tiruvarur 610005, Tamil Nadu, India
| | - Esaki Muthu Shankar
- Infection
Biology, Department of Life Sciences, Central
University of Tamil Nadu, Neelakudi, Tiruvarur 610005, Tamilnadu, India
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15
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Cheah CW, Al-Maleki AR, Vaithilingam RD, Vadivelu J, Sockalingam S, Baharuddin NA, Bartold PM. Associations between inflammation-related LL-37 with subgingival microbial dysbiosis in rheumatoid arthritis patients. Clin Oral Investig 2022; 26:4161-4172. [PMID: 35257247 DOI: 10.1007/s00784-022-04388-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/11/2022] [Indexed: 12/19/2022]
Abstract
OBJECTIVE This study investigated the subgingival microbial profile of rheumatoid arthritis (RA) patients and its associations with disease parameters and the inflammation-related antimicrobial peptide, LL-37. METHODS RA and non-RA (NRA) patients were assessed for periodontal status and divided into periodontitis (CP), gingivitis (G), and healthy (H) groups. Subgingival plaque 16s rRNA gene sequencing data was processed and analyzed using the CLC Genomic Workbench (Qiagen). Bacterial diversity and co-occurrence patterns were examined. Differential abundance between groups was also investigated. Associations between bacterial genera with disease parameters and LL-37 levels were explored qualitatively using canonical correlation analysis. RESULTS Subgingival microbial community clustered in CP status. Co-occurrence network in NRA-H was dominated by health-associated genera, while the rest of the networks' key genera were both health- and disease-associated. RA-CP displayed highly inter-generic networks with a statistically significant increase in periodontal disease-associated genera (p<0.05). In NRA-H, disease parameters and LL-37 were correlated positively with disease-associated genera while negatively with health-associated genera. However, in the remaining groups, mixed positive and negative correlations were noted with genera. CONCLUSION RA patients demonstrated subgingival microbial dysbiosis where the bacteria networks were dominated by health- and disease-associated genera. Mixed correlations with disease parameters and LL-37 levels were noted. CLINICAL RELEVANCE The subgingival microbial dysbiosis in RA may predispose these patients to developing periodontal inflammation with an associated detrimental effect on host immune responses. Routine periodontal assessment may allow initiation of treatment strategies to minimize the effects of gingival inflammation on the existing heightened immune response present in RA patients.
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Affiliation(s)
- Chia Wei Cheah
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Anis Rageh Al-Maleki
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Rathna Devi Vaithilingam
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Sargunan Sockalingam
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Nor Adinar Baharuddin
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, 50603, Kuala Lumpur, Malaysia
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16
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Cheok YY, Tan GMY, Fernandez KC, Chan YT, Lee CYQ, Cheong HC, Looi CY, Vadivelu J, Abdullah S, Wong WF. Corrigendum: Podoplanin Drives Motility of Active Macrophage via Regulating Filamin C During Helicobacter pylori Infection. Front Immunol 2022; 13:857795. [PMID: 35185941 PMCID: PMC8848349 DOI: 10.3389/fimmu.2022.857795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 11/15/2022] Open
Affiliation(s)
- Yi Ying Cheok
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Grace Min Yi Tan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Keith Conrad Fernandez
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Yee Teng Chan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chalystha Yie Qin Lee
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Heng Choon Cheong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chung Yeng Looi
- School of Bioscience, Taylor's University, Subang Jaya, Selangor, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Suhailah Abdullah
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Won Fen Wong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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17
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Zulkefli NJ, Teh CSJ, Mariappan V, Ngoi ST, Vadivelu J, Ponnampalavanar S, Chai LC, Chong CW, Yap IKS, Vellasamy KM. Genomic comparison and phenotypic profiling of small colony variants of Burkholderia pseudomallei. PLoS One 2021; 16:e0261382. [PMID: 34910764 PMCID: PMC8673655 DOI: 10.1371/journal.pone.0261382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 11/30/2021] [Indexed: 11/18/2022] Open
Abstract
Burkholderia pseudomallei (B. pseudomallei) is an intracellular pathogen that causes melioidosis, a life-threatening infection in humans. The bacterium is able to form small colony variants (SCVs) as part of the adaptive features in response to environmental stress. In this study, we characterize the genomic characteristics, antimicrobial resistance (AMR), and metabolic phenotypes of B. pseudomallei SCV and wild type (WT) strains. Whole-genome sequence analysis was performed to characterize the genomic features of two SCVs (CS and OS) and their respective parental WT strains (CB and OB). Phylogenetic relationship between the four draft genomes in this study and 19 publicly available genomes from various countries was determined. The four draft genomes showed a close phylogenetic relationship with other genomes from Southeast Asia. Broth microdilution and phenotype microarray were conducted to determine the AMR profiles and metabolic features (carbon utilization, osmolytes sensitivity, and pH conditions) of all strains. The SCV strains exhibited identical AMR phenotype with their parental WT strains. A limited number of AMR-conferring genes were identified in the B. pseudomallei genomes. The SCVs and their respective parental WT strains generally shared similar carbon-utilization profiles, except for D,L-carnitine (CS), g-hydroxybutyric acid (OS), and succinamic acid (OS) which were utilized by the SCVs only. No difference was observed in the osmolytes sensitivity of all strains. In comparison, WT strains were more resistant to alkaline condition, while SCVs showed variable growth responses at higher acidity. Overall, the genomes of the colony morphology variants of B. pseudomallei were largely identical, and the phenotypic variations observed among the different morphotypes were strain-specific.
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Affiliation(s)
- Noorfatin Jihan Zulkefli
- Faculty of Medicine, Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Cindy Shuan Ju Teh
- Faculty of Medicine, Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
- * E-mail: (CSJT); (KMV)
| | - Vanitha Mariappan
- Faculty of Health Sciences, Centre of Toxicology and Health Risk Studies (CORE), Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Soo Tein Ngoi
- Faculty of Medicine, Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Faculty of Medicine, Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
| | | | - Lay Ching Chai
- Faculty of Science, Institute of Biological Sciences, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Chun Wie Chong
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
- Institute for Research, Development & Innovation, International Medical University, Kuala Lumpur, Malaysia
| | - Ivan Kok Seng Yap
- Sarawak Research and Development Council, Kuching, Sarawak, Malaysia
| | - Kumutha Malar Vellasamy
- Faculty of Medicine, Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
- * E-mail: (CSJT); (KMV)
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18
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Barathan M, Zulpa AK, Mee Hoong S, Vellasamy KM, Vadivelu J. Synergistic effect of hyperforin and paclitaxel on growth inhibition, apoptotic mediator activation in MCF-7 human breast cancer cells. Journal of Taibah University for Science 2021. [DOI: 10.1080/16583655.2021.2010910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Muttiah Barathan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Ahmad Khusairy Zulpa
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - See Mee Hoong
- Department of Surgery, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kumutha Malar Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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Cheok YY, Lee CYQ, Cheong HC, Vadivelu J, Looi CY, Abdullah S, Wong WF. An Overview of Helicobacter pylori Survival Tactics in the Hostile Human Stomach Environment. Microorganisms 2021; 9:microorganisms9122502. [PMID: 34946105 PMCID: PMC8705132 DOI: 10.3390/microorganisms9122502] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 11/28/2021] [Accepted: 11/29/2021] [Indexed: 12/17/2022] Open
Abstract
Helicobacter pylori is well established as a causative agent for gastritis, peptic ulcer, and gastric cancer. Armed with various inimitable virulence factors, this Gram-negative bacterium is one of few microorganisms that is capable of circumventing the harsh environment of the stomach. The unique spiral structure, flagella, and outer membrane proteins accelerate H. pylori movement within the viscous gastric mucosal layers while facilitating its attachment to the epithelial cells. Furthermore, secretion of urease from H. pylori eases the acidic pH within the stomach, thus creating a niche for bacteria survival and replication. Upon gaining a foothold in the gastric epithelial lining, bacterial protein CagA is injected into host cells through a type IV secretion system (T4SS), which together with VacA, damage the gastric epithelial cells. H. pylori does not only establishes colonization in the stomach, but also manipulates the host immune system to permit long-term persistence. Prolonged H. pylori infection causes chronic inflammation that precedes gastric cancer. The current review provides a brief outlook on H. pylori survival tactics, bacterial-host interaction and their importance in therapeutic intervention as well as vaccine development.
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Affiliation(s)
- Yi Ying Cheok
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (Y.Y.C.); (C.Y.Q.L.); (H.C.C.); (J.V.)
| | - Chalystha Yie Qin Lee
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (Y.Y.C.); (C.Y.Q.L.); (H.C.C.); (J.V.)
| | - Heng Choon Cheong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (Y.Y.C.); (C.Y.Q.L.); (H.C.C.); (J.V.)
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (Y.Y.C.); (C.Y.Q.L.); (H.C.C.); (J.V.)
| | - Chung Yeng Looi
- School of Biosciences, Faculty of Health & Medical Sciences, Taylor’s University, Subang Jaya 47500, Malaysia;
| | - Suhailah Abdullah
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia;
| | - Won Fen Wong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (Y.Y.C.); (C.Y.Q.L.); (H.C.C.); (J.V.)
- Correspondence:
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Mariappan V, Vellasamy KM, Mohamad NA, Subramaniam S, Vadivelu J. OneHealth Approaches Contribute Towards Antimicrobial Resistance: Malaysian Perspective. Front Microbiol 2021; 12:718774. [PMID: 34759896 PMCID: PMC8573254 DOI: 10.3389/fmicb.2021.718774] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/16/2021] [Indexed: 11/15/2022] Open
Abstract
On a global scale, antimicrobial resistance (AMR) is recognized as a One Health challenge due to the continual and increased development and distribution of resistant microbes and genes among humans, animals, and the environment. These sectors contribute to the increase in AMR, as antibiotics are widely used in healthcare to treat or prevent bacterial infection; as growth enhancers, therapeutics and metaphylactics in animal husbandry; and transmitted in the environment through irrigation using wastewater or inappropriate disposal and treatment of human and agricultural waste. However, there is a major drawback in terms of the lack of research assessing the coexistence of AMR in these sectors. Extensive research highlighted food–animal manufacture structures that are likely to harbor reservoirs or promote transmission of AMR, in addition to increasing human colonization with AMR commensal bacteria. Numerous antibiotic stewardship policies have been designed and implemented in medical practices and animal husbandry in high- and middle-income countries. However, research concentrating on high-income settings, attitudes, emotions, and beliefs on the utilization of antimicrobials remain underexplored in lower- and middle-income countries such as Malaysia. Microbiological, epidemiological, and social science exploration are required at community and farming across the One Health range to fill huge gaps in information and knowledge of AMR. Manipulating human activities and character associated with antibiotics is a multifaceted progression that includes elements like knowledge, social behavior, attitudes, approaches, social standards, socioeconomic settings, peer pressure, experiences, and biophysical environment. Therefore, understanding these aspects in the utilization of antimicrobial drugs among the different sectors is essential to develop and implement policies to curb AMR development and transmission that overarch all sectors within the One Health consortium in Malaysia.
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Affiliation(s)
- Vanitha Mariappan
- Centre of Toxicology and Health Risk Studies (CORE), Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Kumutha Malar Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Nor Alia Mohamad
- Biomedical Science Programme, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Sreeramanan Subramaniam
- School of Biological Sciences, Universiti Sains Malaysia, George Town, Malaysia.,Faculty of Chemical Engineering Technology, Universiti Malaysia Perlis, Arau, Malaysia.,Centre for Chemical Biology, Universiti Sains Malaysia, Bayan Lepas, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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Barathan M, Vellasamy KM, Ibrahim ZA, Mariappan V, Hoong SM, Vadivelu J. Zerumbone mediates apoptosis and induces secretion of proinflammatory cytokines in breast carcinoma cell culture. Iran J Basic Med Sci 2021; 24:1538-1545. [PMID: 35317109 PMCID: PMC8917841 DOI: 10.22038/ijbms.2021.58573.13012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 10/10/2021] [Indexed: 11/06/2022]
Abstract
Objectives To investigate the potential anti-breast cancer activity of zerumbone in regulating apoptotic mediators and cytokines in comparison with paclitaxel (positive control). Materials and Methods In this study, assays such as viability, apoptosis, reactive oxygen species, cell cycle, DNA fragmentation, and cytokines were carried out on MCF-7 cells after treatment with zerumbone and paclitaxel. Results The results showed that zerumbone demonstrated a higher (18-fold) IC50 value (126.7 µg/ml) than paclitaxel (7.29 µg/ml) in order to suppress proliferation and induce cell death of MCF-7. The cell cycle arrest at the G0/G1 phase and excessive intracellular ROS production during the in vitro zerumbone treatment indicated occurrence of apoptotic cell death although nuclear DNA fragmentation was not observed. The flow cytometer analysis of treated cells revealed secretion of proinflammatory cytokines suggesting the potential immunomodulatory activity of zerumbone. Conclusion Although, zerumbone exhibited a higher IC50 value compared with paclitaxel yet its anticancer activity against MCF-7 cells is still parallel to paclitaxel hence zerumbone has the potential to be an antineoplastic agent in the treatment of breast cancer especially the luminal type A.
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Affiliation(s)
- Muttiah Barathan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia
| | - Kumutha Malar Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia
| | - Zaridatul Aini Ibrahim
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia
| | - Vanitha Mariappan
- Center of Toxicology and Health Risk Studies (CORE), Faculty of Health Sciences, National University of Malaysia, Jalan Raja Muda Aziz, Kuala Lumpur 50300, Malaysia
| | - See Mee Hoong
- Department of Surgery, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia,Corresponding author: Jamuna Vadivelu. Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia.
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Cheok YY, Tan GMY, Fernandez KC, Chan YT, Lee CYQ, Cheong HC, Looi CY, Vadivelu J, Abdullah S, Wong WF. Podoplanin Drives Motility of Active Macrophage via Regulating Filamin C During Helicobacter pylori Infection. Front Immunol 2021; 12:702156. [PMID: 34707599 PMCID: PMC8543000 DOI: 10.3389/fimmu.2021.702156] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 09/10/2021] [Indexed: 01/12/2023] Open
Abstract
Podoplanin (Pdpn) is a mucin-type transmembrane protein that has been implicated in multiple physiological settings including lymphangiogenesis, platelet aggregation, and cancer metastasis. Here, we reported an absence of Pdpn transcript expression in the resting mouse monocytic macrophages, RAW264.7 cells; intriguingly, a substantial upregulation of Pdpn was observed in activated macrophages following Helicobacter pylori or lipopolysaccharide stimulation. Pdpn-knockout macrophages demonstrated intact phagocytic and intracellular bactericidal activities comparable to wild type but exhibited impaired migration due to attenuated filopodia formation. In contrast, an ectopic expression of Pdpn augmented filopodia protrusion in activated macrophages. NanoString analysis uncovered a close dependency of Filamin C gene on the presence of Pdpn, highlighting an involvement of Filamin C in modulation of actin polymerization activity, which controls cell filopodia formation and migration. In addition, interleukin-1β production was significantly declined in the absence of Pdpn, suggesting a role of Pdpn in orchestrating inflammation during H. pylori infection besides cellular migration. Together, our findings unravel the Pdpn network that modulates movement of active macrophages.
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Affiliation(s)
- Yi Ying Cheok
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Grace Min Yi Tan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Keith Conrad Fernandez
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Yee Teng Chan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chalystha Yie Qin Lee
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Heng Choon Cheong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chung Yeng Looi
- School of Bioscience, Taylor's University, Subang Jaya, Selangor, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Suhailah Abdullah
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Won Fen Wong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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Barathan M, Riazalhosseini B, Iyadorai T, Vellasamy KM, Vadivelu J, Chang LY, Zulpa AK, Larsson M, Shankar EM, Mohamed R. Comparative expression of pro-inflammatory and apoptotic biosignatures in chronic HBV-infected patients with and without liver cirrhosis. Microb Pathog 2021; 161:105231. [PMID: 34619310 DOI: 10.1016/j.micpath.2021.105231] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 09/22/2021] [Accepted: 10/01/2021] [Indexed: 11/30/2022]
Abstract
The interplay of immune mediators is paramount to optimal host anti-viral immune responses, especially against chronic hepatitis B virus (HBV) infection. Here, we investigated the dynamic changes in host immune responses in chronic HBV-infected individuals with and without liver cirrhosis by examining the signatures of apoptosis and plasma levels of pro-inflammatory cytokines, chemokines, and cytotoxic proteins. A total of 40 chronic HBV patients with and without liver cirrhosis were studied for plasma levels of immune mediators, and signatures of apoptosis in peripheral blood mononuclear cells (PBMCs). The intracellular concentrations of reactive oxygen species (ROS) in patients with chronic HBV with liver cirrhosis was relatively higher as compared to chronic HBV patients. The onset of apoptosis was sustained due to ongoing liver inflammation in concert with plasma TNF-α and IL-6 levels. Plasma VEGF was upregulated among chronic HBV patients with liver cirrhosis, whereas CCL2, CCL5 and granzyme B levels were down-regulated. High levels of ROS, IL-6 and TNF-α correlated with ongoing inflammation among chronic HBV patients with liver cirrhosis, which likely attributed to the expression of biosignatures of apoptosis and activation in immune cells.
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Affiliation(s)
- Muttiah Barathan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, 50603, Malaysia
| | - Behnaz Riazalhosseini
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, 50603, Malaysia
| | - Thevambiga Iyadorai
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, 50603, Malaysia
| | - Kumutha Malar Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, 50603, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, 50603, Malaysia
| | - Li-Yen Chang
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, 50603, Malaysia
| | - Ahmad Khusairy Zulpa
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, 50603, Malaysia
| | - Marie Larsson
- Division of Molecular Medicine and Virology, Department of Biomedicine and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Esaki M Shankar
- Infection Biology, Department of Life Sciences, Central University of Tamil Nadu, Thiruvarur, 610 005, India.
| | - Rosmawati Mohamed
- Department of Medicine, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, 50603, Malaysia.
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Malathi G, Vadivelu J. <i>In-vitro</i> antioxidant, anti-inflammatory and cytotoxic activity of <i>Cucumis melo L. </i>of ethanolic extract. Biomedicine (Taipei) 2021. [DOI: 10.51248/.v41i2.1054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Introduction and Aim: Cucumis melo L. commonly known as wild melon (in English) belongs to the family Cucurbitaceae and well distributed in rural areas. Cucumis melo L. is a annual climbing or perennial herb, distributed almost throughout India and neighbouring countries. Nowadays food wastes are a major concern. On the other hand, the demand for natural valuable compounds to human health is increasing. These by-products contain phytochemical compounds with great nutritional and functional potentials. The fruits of this plant possess the abortifacient property and have antitussive, antioxidant, digestive, cytotoxic and anti-inflammatory properties.
Materials and Methods: The ethanolic extract was used to determine the antioxidant scavenging activity using DPPH method, protein denaturation for anti inflammatory studies, as well as in vitro cytotoxic activity by brine shrimp lethal assay (BSLA).
Results: The results obtained indicated highest antioxidant activity as compared to DPPH methods. The protein denaturation test showed the ethanolic extracts of Cucumis melo L. had effective anti-inflammatory activity. Extracts of Cucumis melo L. also registered potential cytotoxic activities by BSLA. This study provides the basis for further investigation of Cucumis melo L. for potential identification of novel bioactive compounds with therapeutic properties.
Conclusion: The presence of phytoconstituents such as flavonoids, terpenoids, alkaloids, may indeed assist to the antioxidant activity of fruit extract. That this next thing that must be done will be to conduct in vivo experiments and discern the histopathological mechanism.
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Choh LC, Ong GH, Chua EG, Vellasamy KM, Mariappan V, Khan AM, Wise MJ, Wong KT, Vadivelu J. Absence of BapA type III effector protein affects Burkholderia pseudomallei intracellular lifecycle in human host cells. Process Biochem 2021. [DOI: 10.1016/j.procbio.2021.05.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Mariappan V, Vellasamy KM, Barathan M, Girija ASS, Shankar EM, Vadivelu J. Hijacking of the Host's Immune Surveillance Radars by Burkholderia pseudomallei. Front Immunol 2021; 12:718719. [PMID: 34456925 PMCID: PMC8384953 DOI: 10.3389/fimmu.2021.718719] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 07/12/2021] [Indexed: 11/20/2022] Open
Abstract
Burkholderia pseudomallei (B. pseudomallei) causes melioidosis, a potentially fatal disease for which no licensed vaccine is available thus far. The host-pathogen interactions in B. pseudomallei infection largely remain the tip of the iceberg. The pathological manifestations are protean ranging from acute to chronic involving one or more visceral organs leading to septic shock, especially in individuals with underlying conditions similar to COVID-19. Pathogenesis is attributed to the intracellular ability of the bacterium to ‘step into’ the host cell’s cytoplasm from the endocytotic vacuole, where it appears to polymerize actin filaments to spread across cells in the closer vicinity. B. pseudomallei effectively evades the host’s surveillance armory to remain latent for prolonged duration also causing relapses despite antimicrobial therapy. Therefore, eradication of intracellular B. pseudomallei is highly dependent on robust cellular immune responses. However, it remains ambiguous why certain individuals in endemic areas experience asymptomatic seroconversion, whereas others succumb to sepsis-associated sequelae. Here, we propose key insights on how the host’s surveillance radars get commandeered by B. pseudomallei.
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Affiliation(s)
- Vanitha Mariappan
- Center for Toxicology and Health Risk Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Kumutha Malar Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Muttiah Barathan
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - A S Smiline Girija
- Department of Microbiology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai, India
| | - Esaki M Shankar
- Infection Biology, Department of Life Sciences, Central University of Tamil Nadu, Thiruvarur, India
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
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27
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Barathan M, Zulpa AK, Vellasamy KM, Mariappan V, Shivashekaregowda NKH, Ibrahim ZA, Vadivelu J. Cytotoxic Activity of Isoniazid Derivative in Human Breast Cancer Cells. In Vivo 2021; 35:2675-2685. [PMID: 34410956 DOI: 10.21873/invivo.12551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM Isoniazid is an antibiotic used for the treatment of tuberculosis. Previously, we found that the isoniazid derivative (E)-N'-(2,3,4-trihydroxybenzylidene) isonicotinohydrazide (ITHB4) could be developed as novel antimycobacterial agent by lead optimization. We further explored the ability of this compound compared to zerumbone in inhibiting the growth of MCF-7 breast cancer cells. MATERIALS AND METHODS Cytotoxicity was measured by the MTT assay and further confirmed via apoptosis, ROS, cell cycle, DNA fragmentation and cytokine assays. RESULTS ITHB4 demonstrated a lower IC50 compared to zerumbone in inhibiting the proliferation of MCF-7 cells. ITHB4 showed no toxicity against normal breast and human immune cells. Apoptosis assay revealed that ITHB4, at a concentration equal to the IC50, induces apoptosis of MCF-7 cells and cell cycle arrest at the sub-G1 and G2/M phases. ITHB4 triggered accumulation of intracellular ROS and nuclear DNA fragmentation. Secretion of pro-inflammatory cytokines induced inflammation and potentially immunogenic cell death. CONCLUSION ITHB4 has almost similar chemotherapeutic properties as zerumbone in inhibiting MCF-7 growth, and hence provide the basis for further experiments in animal models.
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Affiliation(s)
- Muttiah Barathan
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Ahmad Khusairy Zulpa
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Kumutha Malar Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Vanitha Mariappan
- Center of Toxicology and Health Risk Studies (CORE), Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | | | - Zaridatul Aini Ibrahim
- Department of Pharmacology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia;
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Zulpa AK, Barathan M, Iyadorai T, Chandramathi S, Vellasamy KM, Vadivelu J, Gan GG, Anuar NA. Release of pro-inflammatory cytokines TNF-α, IFN-γ and IL-6 by Burkholderia pseudomallei- stimulated peripheral blood mononucleocytes of acute myeloid leukemia patients. Trop Biomed 2021; 38:180-185. [PMID: 34172708 DOI: 10.47665/tb.38.2.055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acute myeloid leukemia (AML) is a malignant disease progressed from abnormal production of immature myeloid cells, which is often associated with concurrent infections after diagnosis. It was widely established that infections are the major contributors to mortality in this group due to the prevalency of neutropenia. Gram-negative Burkholderia pseudomallei is the causative agent of melioidosis. This disease had been reported in several neutropenic cancer patients undergoing chemotherapy resulting in severe clinical presentations and high mortalities which is in need of critical attention. Studies show that cytokines are important mediators of melioidosis progression and low neutrophil counts are associated with progression of its severity. However, to date, there are no reports on cytokine production in neutropenic cancer patients who are prone to melioidosis. Hence, here we assessed the cytokine production in neutropenic AML patients by introducing B. pseudomallei to their peripheral blood mononuclear cell (PBMC) culture in vitro. We observed that inflammatory response related cytokines namely TNF-α, IFN-γ IL-6 and IL-10 were highly circulated in infected PBMCs suggesting that these cytokines may play important roles in the progression of severity in melioidosis infected neutropenic patients.
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Affiliation(s)
- A K Zulpa
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - M Barathan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - T Iyadorai
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - S Chandramathi
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - K M Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - J Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - G G Gan
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - N A Anuar
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
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Foong CC, Bashir Ghouse NL, Lye AJ, Khairul Anhar Holder NA, Pallath V, Hong WH, Sim JH, Vadivelu J. A qualitative study on self-regulated learning among high performing medical students. BMC Med Educ 2021; 21:320. [PMID: 34090439 PMCID: PMC8178823 DOI: 10.1186/s12909-021-02712-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 05/04/2021] [Indexed: 06/06/2023]
Abstract
BACKGROUND Self-regulated learning (SRL) is an important contributing element to the academic success of students. Literature suggests that the understanding of SRL among medical students is obscure as there is still some uncertainty about whether high performing medical students use SRL. This study explored the characteristics of high performing medical students from the SRL perspective to gain a better understanding of the application of SRL for effective learning. METHODS Twenty-one students who scored at the 90th percentile in written knowledge-based assessment consented to participate in this study. Each student wrote a guided reflective journal and subsequently attended a semi-structured interview. Students were prompted to explain the rationales for their answers. The data were then analysed using thematic analysis to identify patterns among these students from the SRL perspective. Two coders analysed the data independently and discussed the codes to reach a consensus. RESULTS High performing students set goals, made plans, and motivated themselves to achieve the goals. They put consistent efforts into their studies and applied effective learning strategies. They also employed coping mechanisms to deal with challenges. High performing students regularly evaluated their performance and adopted new strategies. CONCLUSIONS This study reported that high performing students applied SRL and described the rationales of practice. Medical schools could design SRL-driven interventions to enhance the learning experiences of medical students. Recommendations are made for students on how to apply SRL.
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Affiliation(s)
- Chan Choong Foong
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Nur Liyana Bashir Ghouse
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - An Jie Lye
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Nurul Atira Khairul Anhar Holder
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Vinod Pallath
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Wei-Han Hong
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Joong Hiong Sim
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Medical Education and Research Development Unit (MERDU), Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
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Sim JH, Foong CC, Pallath V, Hong WH, Vadivelu J. A Malaysian version of learning space preferences: a validation study. Int J Med Educ 2021; 12:86-93. [PMID: 34049286 PMCID: PMC8411344 DOI: 10.5116/ijme.6082.7c41] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 04/23/2021] [Indexed: 06/12/2023]
Abstract
OBJECTIVES This study aimed to validate a Malaysian version of a revised learning space questionnaire, as well as to test the utility of the revised questionnaire as a tool to investigate learning space preferences in a Malaysian medical school. METHODS This is a cross-sectional survey. A convenient sample of 310 preclinical students of a public medical school in Malaysia were invited to participate. Validation data were collected using a revised 40-item, 5-point Likert scale learning space questionnaire. The questionnaires were administered online via a student e-learning platform. Data analysis was conducted using IBM SPSS version 24. Exploratory factor analysis was conducted to examine the factor structure of the revised questionnaire to provide evidence for construct validity. To assess the internal consistency of the revised questionnaire, Cronbach's alpha coefficients (α) were computed across all the items as well as for items within each of the factor. RESULTS A total of 223 (71.94%) preclinical students completed and returned the questionnaire. In the final analysis, exploratory factor analysis with principal axis factoring and an oblimin rotation identified a six-factor, 20-item factor solution. Reliability analysis reported good internal consistency for the revised questionnaire, with an overall Cronbach's alpha of 0.845, and Cronbach's alpha ranging from 0.800 to 0.925 for the six factors. CONCLUSIONS This study established evidence for the construct validity and internal consistency of the revised questionnaire. The revised questionnaire appears to have utility as an instrument to investigate learning space preferences in Malaysian medical schools.
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Affiliation(s)
- Joong Hiong Sim
- Medical Education and Research Development Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chan Choong Foong
- Medical Education and Research Development Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Vinod Pallath
- Medical Education and Research Development Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Wei-Han Hong
- Medical Education and Research Development Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Medical Education and Research Development Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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Sim JH, Pallath V, Vadivelu J. 'Student-steered' PBL session: From necessity to opportunity. Med Educ 2021; 55:633. [PMID: 33660309 DOI: 10.1111/medu.14514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
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Priyadarshini S, Sonsudin F, Mainal A, Yahya R, Gopinath V, Vadivelu J, Alarjani KM, Al Farraj DA, Yehia HM. Phytosynthesis of biohybrid nano-silver anchors enhanced size dependent photocatalytic, antibacterial, anticancer properties and cytocompatibility. Process Biochem 2021. [DOI: 10.1016/j.procbio.2020.11.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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33
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Teh CSJ, Yap PSX, Zulkefli NJ, Subramaniam P, Sit PS, Kong ZX, Chong CW, Vellasamy KM, Mariappan V, Ponnampalavanar S, Vadivelu J. Overview of the distribution of Burkholderia pseudomallei sequence types and the Emergence of sequence type 1342 in Malaysia. Transbound Emerg Dis 2021; 69:477-484. [PMID: 33506647 DOI: 10.1111/tbed.14005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/24/2021] [Accepted: 01/25/2021] [Indexed: 11/29/2022]
Abstract
Burkholderia pseudomallei, a Gram-negative bacterial pathogen that causes melioidosis, is of public health importance in endemic areas including Malaysia. An investigation of the molecular epidemiology links of B. pseudomallei would contribute to better understanding of the clonal relationships, transmission dynamics and evolutionary change. Multilocus sequence typing (MLST) of 45 clinical B. pseudomallei isolates collected from sporadic melioidosis cases in Malaysia was performed. In addition, a total of 449 B. pseudomallei Malaysian strains submitted to the MLST database from 1964 until 2019 were included in the temporal analysis to determine the endemic sequence types (STs), emergence and re-emergence of ST(s). In addition, strain-specific distribution was evaluated using BURST tool. Genotyping of 45 clinical strains was resolved into 12 STs, and the majority were affiliated with ST46 (n = 11) and ST1342 (n = 7). Concomitantly, ST46 was the most prevalent ST in Malaysia, which was first reported in 1964. All the Malaysian B. pseudomallei strains were resolved into 76 different STs with 36 of them uniquely present only in Malaysia. ST1342 was most closely related to ST1034, in which both STs were unique to Malaysia and first isolated from soil samples in Pahang, a state in Malaysia. The present study revealed a high diversity of B. pseudomallei in Malaysia. Localized evolution giving rise to the emergence of new STs was observed, suggesting that host and environmental factors play a crucial role in the evolutionary changes in B. pseudomallei.
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Affiliation(s)
- Cindy Shuan Ju Teh
- Department of Medical Microbiology, University of Malaya, Kuala Lumpur, Malaysia
| | - Polly Soo Xi Yap
- Department of Medical Microbiology, University of Malaya, Kuala Lumpur, Malaysia
| | | | - Prasanna Subramaniam
- Department of Medical Microbiology, University of Malaya, Kuala Lumpur, Malaysia
| | - Pik San Sit
- Department of Medical Microbiology, University of Malaya, Kuala Lumpur, Malaysia
| | - Zhi Xian Kong
- Department of Medical Microbiology, University of Malaya, Kuala Lumpur, Malaysia
| | - Chun Wie Chong
- School of Pharmacy, Monash University Malaysia, Selangor, Malaysia.,Institute of Research, Development and Innovation, International Medical University, Kuala Lumpur, Malaysia
| | | | - Vanitha Mariappan
- Faculty of Health Sciences, Centre of Toxicology and Health Risk Studies (CORE), National University of Malaysia, Kuala Lumpur, Malaysia
| | | | - Jamuna Vadivelu
- Department of Medical Microbiology, University of Malaya, Kuala Lumpur, Malaysia
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Muthusami S, Vidya B, Shankar EM, Vadivelu J, Ramachandran I, Stanley JA, Selvamurugan N. The Functional Significance of Endocrine-immune Interactions in Health and Disease. Curr Protein Pept Sci 2021; 21:52-65. [PMID: 31702489 DOI: 10.2174/1389203720666191106113435] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/30/2019] [Accepted: 10/03/2019] [Indexed: 02/06/2023]
Abstract
Hormones are known to influence various body systems that include skeletal, cardiac, digestive, excretory, and immune systems. Emerging investigations suggest the key role played by secretions of endocrine glands in immune cell differentiation, proliferation, activation, and memory attributes of the immune system. The link between steroid hormones such as glucocorticoids and inflammation is widely known. However, the role of peptide hormones and amino acid derivatives such as growth and thyroid hormones, prolactin, dopamine, and thymopoietin in regulating the functioning of the immune system remains unclear. Here, we reviewed the findings pertinent to the functional role of hormone-immune interactions in health and disease and proposed perspective directions for translational research in the field.
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Affiliation(s)
- Sridhar Muthusami
- Department of Biochemistry, Karpagam Academy of Higher Education, Eachanari, Coimbatore 641021, Tamil Nadu, India
| | - Balasubramanian Vidya
- Department of Biochemistry, Karpagam Academy of Higher Education, Eachanari, Coimbatore 641021, Tamil Nadu, India
| | - Esaki M Shankar
- Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Thiruvarur 610005, India
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia
| | - Ilangovan Ramachandran
- Department of Endocrinology, Dr. ALM PG Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai 600 113, Tamil Nadu, India
| | - Jone A Stanley
- College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas 77843, United States
| | - Nagarajan Selvamurugan
- Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Tamil Nadu, India
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Sakthi Mohan P, Sonsuddin F, Mainal AB, Yahya R, Venkatraman G, Vadivelu J, Al-Farraj DA, Al-Mohaimeed AM, Alarijani KM. Facile In-Situ Fabrication of a Ternary ZnO/TiO 2/Ag Nanocomposite for Enhanced Bactericidal and Biocompatibility Properties. Antibiotics (Basel) 2021; 10:antibiotics10010086. [PMID: 33477455 PMCID: PMC7831044 DOI: 10.3390/antibiotics10010086] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/14/2020] [Accepted: 12/29/2020] [Indexed: 01/27/2023] Open
Abstract
This paper presents for the first time a successful fabrication of ternary ZnO/TiO2/Ag nanocomposites consisting of zinc oxide (ZnO), titania (TiO2) and silver (Ag) nanoparticles (NPs) synthesised using Morinda citrifolia fruit (MCF) extract. ZnONPs were synthesised using the co-precipitation method, and TiO2 and Ag were introduced into the precursor solutions under microwave irradiation to obtain ZnO/TiO2/Ag nanocomposites (NCs). This material demonstrated enhanced bactericidal effect towards bacterial pathogens compared to that of the binary TiO2/Ag, Ag and TiO2 alone. In vitro cytotoxicity results of the as-synthesised ZnO/TiO2/AgNCs on RAW 264.7 macrophages and A549 cell lines revealed a negative role in cytotoxicity, but contributed astoundingly towards antimicrobials as compared of Ag alone and binary Ag/TiO2. This study shows that the resultant ternary metal/bi-semiconductor nanocomposites may provide a therapeutic strategy for the eradication of bacterial pathogens without affecting the healthy mammalian cells.
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Affiliation(s)
- Priyadarshini Sakthi Mohan
- Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia; (P.S.M.); (A.B.M.)
| | - Faridah Sonsuddin
- Centre for Foundation Studies in Science, University of Malaya, Kuala Lumpur 50603, Malaysia;
| | - Azizah Binti Mainal
- Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia; (P.S.M.); (A.B.M.)
| | - Rosiyah Yahya
- Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia; (P.S.M.); (A.B.M.)
- Correspondence:
| | - Gopinath Venkatraman
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (G.V.); (J.V.)
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (G.V.); (J.V.)
| | - Dunia A. Al-Farraj
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia; (D.A.A.-F.); (K.M.A.)
| | - Amal M. Al-Mohaimeed
- Department of Chemistry, College of Science, King Saud University, P.O. Box 22452, Riyadh 11495, Saudi Arabia;
| | - Khaloud Mohammed Alarijani
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia; (D.A.A.-F.); (K.M.A.)
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36
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Ying CY, Yi TGM, Vadivelu J, Yeng LC, Fen WW. Helicobacter pylori-infection induces podoplanin-mediated migration of macrophages. Int J Infect Dis 2020. [DOI: 10.1016/j.ijid.2020.09.377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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37
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Gopinath V, MubarakAli D, Vadivelu J, Manjunath Kamath S, Syed A, Elgorban AM. Synthesis of biocompatible chitosan decorated silver nanoparticles biocomposites for enhanced antimicrobial and anticancer property. Process Biochem 2020. [DOI: 10.1016/j.procbio.2020.09.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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38
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Munusamy K, Loke MF, Vadivelu J, Tay ST. LC-MS analysis reveals biological and metabolic processes essential for Candida albicans biofilm growth. Microb Pathog 2020; 152:104614. [PMID: 33202254 DOI: 10.1016/j.micpath.2020.104614] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 11/05/2020] [Accepted: 11/05/2020] [Indexed: 12/22/2022]
Abstract
Candidiasis is the most common fungal infection associated with high morbidity and mortality among immunocompromised patients. The ability to form biofilm is essential for Candida albicans pathogenesis and drug resistance. In this study, the planktonic cell and biofilm proteomes of C. albicans SC5314 strain analyzed using Liquid Chromatography-Mass Spectrometry (LC-MS) were compared. In total, 280 and 449 proteins are annotated from the planktonic cell and biofilm proteomes, respectively. The biofilm proteome demonstrated significantly higher proportion of proteins associated with the endomembrane system, mitochondrion and cytoplasm than planktonic proteome. Among proteins detected, 143 and 207 biological processes are annotated, of which, 38 and 102 are specific to the planktonic cell and biofilm proteomes, respectively, while 105 are common biological processes. The specific biological processes of C. albicans planktonic cell proteome are associated with cell polarity, energy metabolism and nucleotide (purine) metabolism, oxido-reduction coenzyme metabolic process, monosaccharide and amino acid (methionine) biosynthesis, regulation of anatomical structure morphogenesis and cell cycling, and single organism reproduction. Meanwhile, regulation of cellular macromolecule biosynthesis and metabolism, transcription and gene expression are major biological processes specifically associated with C. albicans biofilm proteome. Biosynthesis of leucine, isoleucine, and thiocysteine are highlighted as planktonic-related pathways, whereas folate metabolism, fatty acid metabolism and biosynthesis of amino acids (lysine, serine and glycine) are highlighted as biofilm-related pathways. In summary, LC-MS-based proteomic analysis reveals different adaptative strategies of C. albicans via specific biological and metabolic processes for planktonic cell and biofilm lifestyles. The mass spectrometry data are available via ProteomeXchange with identifiers PXD007830 (for biofilm proteome) and PXD007831 (for planktonic cell proteome).
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Affiliation(s)
- Komathy Munusamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Mun Fai Loke
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Sun Tee Tay
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
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Venkatramanan M, Sankar Ganesh P, Senthil R, Akshay J, Veera Ravi A, Langeswaran K, Vadivelu J, Nagarajan S, Rajendran K, Shankar EM. Inhibition of Quorum Sensing and Biofilm Formation in Chromobacterium violaceum by Fruit Extracts of Passiflora edulis. ACS Omega 2020; 5:25605-25616. [PMID: 33073086 PMCID: PMC7557254 DOI: 10.1021/acsomega.0c02483] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/12/2020] [Indexed: 05/25/2023]
Abstract
Chromobacterium violaceum (C. violaceum) is a Gram-negative, rod-shaped facultatively anaerobic bacterium implicated with recalcitrant human infections. Here, we evaluated the anti-QS and antibiofilm activities of ethyl acetate extracts of Passiflora edulis (P. edulis) on the likely inactivation of acyl-homoserine lactone (AHL)-regulated molecules in C. violaceum both by in vitro and in silico analyses. Our investigations showed that the sub-MIC levels were 2, 1, and 0.5 mg/mL, and the concentrations showed a marked reduction in violacein pigment production by 75.8, 64.6, and 35.2%. AHL quantification showed 72.5, 52.2, and 35.9% inhibitions, inhibitions of EPS production (72.8, 36.5, and 25.9%), and reductions in biofilm formation (90.7, 69.4, and 51.8%) as compared to a control. Light microscopy and CLSM analysis revealed dramatic reduction in the treated biofilm group as compared to the control. GC-MS analysis showed 20 major peaks whose chemical structures were docked as the CviR ligand. The highest docking score was observed for hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester bonds in the active site of CviR with a binding energy of -8.825 kcal/mol. Together, we found that hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester remarkably interacted with CviR to inhibit the QS system. Hence, we concluded that hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester of P. edulis could likely be evaluated for treating C. violaceum infections.
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Affiliation(s)
- Mahendrarajan Venkatramanan
- Infection
Biology, Department of Life Sciences, Central
University of Tamil Nadu, Neelakudi, Thiruvarur 610 005, India
| | - Pitchaipillai Sankar Ganesh
- Infection
Biology, Department of Life Sciences, Central
University of Tamil Nadu, Neelakudi, Thiruvarur 610 005, India
| | - Renganathan Senthil
- Department
of Bioinformatics, Marudupandiyar College, Vallam, Thanjavur 613403, India
- Lysine
Biotech Private Limited, Periyar Maniammai
University, Periyar Nagar, Vallam, Thanjavur 613403, India
| | - Jeyachandran Akshay
- Infection
Biology, Department of Life Sciences, Central
University of Tamil Nadu, Neelakudi, Thiruvarur 610 005, India
| | | | | | - Jamuna Vadivelu
- Department
of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai,
Kuala Lumpur 50603, Malaysia
| | - Samuthira Nagarajan
- Department
of Chemistry, Central University of Tamil
Nadu, Neelakudi, Thiruvarur 610 005, India
| | | | - Esaki Muthu Shankar
- Infection
Biology, Department of Life Sciences, Central
University of Tamil Nadu, Neelakudi, Thiruvarur 610 005, India
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40
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Menon N, Mariappan V, Vellasamy KM, Samudi C, See JX, Ganesh PS, Saeidi A, Vadivelu J, Shankar EM. Experimental exposure of Burkholderia pseudomallei crude culture filtrate upregulates PD-1 on T lymphocytes. Access Microbiol 2020; 2:acmi000110. [PMID: 32974575 PMCID: PMC7494189 DOI: 10.1099/acmi.0.000110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 01/30/2020] [Indexed: 12/11/2022] Open
Abstract
Burkholderia pseudomallei is the causative agent for melioidosis. Because of its intracellular nature, the bacterium is capable of replicating within a plethora of eukaryotic cell lines. B. pseudomallei can remain dormant within host cells without symptoms for years, causing recrudescent infections. Here, we investigated the pathogenesis mechanism behind the suppression of T cell responses by B. pseudomallei . Peripheral blood mononuclear cells (1×106 cells/well) isolated by Ficoll Paque (Sigma-Aldrich) density gradient centrifugation were incubated with optimized concentrations of bacterial crude culture filtrate antigens (CFAs) (10 ug ml-1) and heat-killed bacteria [1 : 10 multiplicity of infection (m.o.i.)]. Following incubation, cells were investigated for surface expression of coinhibitory molecules by flow cytometry. We found that B. pseudomallei induced the upregulation of programmed death 1 (PD-1), a molecule responsible for T cell exhaustion, on T cells in vitro following exposure to crude CFAs of B. pseudomallei . This upregulation of PD-1 probably contributes to poor immune surveillance and disease pathogenesis.
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Affiliation(s)
- Nivedita Menon
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Vanitha Mariappan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Kumutha M Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Chandramathi Samudi
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Jia-Xiang See
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia
| | - P Sankar Ganesh
- Department of Life Sciences, Central University of Tamil Nadu, Thiruvarur 610 005, Tamilnadu, India
| | - Alireza Saeidi
- Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia.,Present address: Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Esaki Muthu Shankar
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia.,Present address: Department of Life Sciences, Central University of Tamil Nadu, Tamilnadu, Thiruvarur, India
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41
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Cheah CW, Al‐Maleki AR, Vadivelu J, Danaee M, Sockalingam S, Baharuddin NA, Vaithilingam RD. Salivary and serum cathelicidin LL‐37 levels in subjects with rheumatoid arthritis and chronic periodontitis. Int J Rheum Dis 2020; 23:1344-1352. [DOI: 10.1111/1756-185x.13919] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/17/2020] [Accepted: 06/29/2020] [Indexed: 01/22/2023]
Affiliation(s)
- Chia Wei Cheah
- Department of Restorative Dentistry Faculty of Dentistry University of Malaya Kuala Lumpur Malaysia
| | - Anis Rageh Al‐Maleki
- Department of Medical Microbiology Faculty of Medicine University of Malaya Kuala Lumpur Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology Faculty of Medicine University of Malaya Kuala Lumpur Malaysia
| | - Mahmoud Danaee
- Department of Social Preventive Medicine Faculty of Medicine University of Malaya Kuala Lumpur Malaysia
| | - Sargunan Sockalingam
- Department of Medicine Faculty of Medicine University of Malaya Kuala Lumpur Malaysia
| | - Nor Adinar Baharuddin
- Department of Restorative Dentistry Faculty of Dentistry University of Malaya Kuala Lumpur Malaysia
| | - Rathna Devi Vaithilingam
- Department of Restorative Dentistry Faculty of Dentistry University of Malaya Kuala Lumpur Malaysia
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Selvarajoo S, Liew JWK, Tan W, Lim XY, Refai WF, Zaki RA, Sethi N, Wan Sulaiman WY, Lim YAL, Vadivelu J, Vythilingam I. Knowledge, attitude and practice on dengue prevention and dengue seroprevalence in a dengue hotspot in Malaysia: A cross-sectional study. Sci Rep 2020; 10:9534. [PMID: 32533017 PMCID: PMC7293214 DOI: 10.1038/s41598-020-66212-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 05/18/2020] [Indexed: 01/03/2023] Open
Abstract
Dengue has become a global public health problem. Despite reactive efforts by the government in Malaysia, the dengue cases are on the increase. Adequate knowledge, positive attitude and correct practice for dengue control are essential to stamp out the disease. Hence, this study aims to assess the factors associated with dengue knowledge, attitude and practice (KAP), as well as the association with dengue IgM and IgG seropositivity. A community-based cross-sectional study was conducted in a closed, dengue endemic area with multi-storey dwellings . Five hundred individuals (aged 18 years and above) were approached for pre-tested KAP and seroprevalences assessment. The study showed only half of the total participants have good knowledge (50.7%) but they had insufficient knowledge about dengue during pregnancy. 53.2% of people had poor attitude and 50.2% reported poor practice for dengue control. Out of 85 respondents who agreed to participate in the dengue seroprevalence study, 74.1% (n = 63) were positive for dengue IgG and 7.1% (n = 6) were positive for dengue IgM. Among all sociodemographic variable, race is the only independent predicator for all KAP levels (P < 0.05). In conclusion, proactive and sustainable efforts are needed to bring a behavioural change among communities in order to fight dengue outbreaks in endemic areas.
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Affiliation(s)
- Sivaneswari Selvarajoo
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Jonathan Wee Kent Liew
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Wing Tan
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Xin Ying Lim
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Wardha F Refai
- Postgraduate Institute of Medicine (PGIM), Colombo, 7, Sri Lanka
| | - Rafdzah Ahmad Zaki
- Centre for Epidemiology and Evidence Based Practice, Department of Social and Preventive Medicine, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Neha Sethi
- Department of Obstetrics and Gynaecology, University of Malaya Medical Centre (UMMC), 50603, Kuala Lumpur, Malaysia
| | - Wan Yusoff Wan Sulaiman
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Yvonne Ai Lian Lim
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Indra Vythilingam
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia.
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Lee SS, Samarasekera DD, Sim JH, Hong WH, Foong CC, Pallath V, Vadivelu J. Exploring the Cultivation of Self-Regulated Learning (SRL) Strategies Among Pre-Clinical Medical Students in Two Medical Schools. Med Sci Educ 2020; 30:271-280. [PMID: 34457667 PMCID: PMC8368284 DOI: 10.1007/s40670-019-00894-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
PURPOSE Research has shown that many undergraduate students struggle with self-regulated learning (SRL) in clinical year as they are insufficiently supported by the staff in the early year to prepare them for the transition. Hence, this study aims to find out the SRL strategies and the approaches that could promote SRL among pre-clinical students in two medical schools. METHOD This is a mixed-method study. The Motivated Strategies for Learning Questionnaire (MSLQ) was used to collect student SRL strategies while semi-structured interviews with faculty members and focus group discussions with students were used to gather data on the approaches that promote SRL. Student MSLQ was analysed using descriptive statistics while interviews were transcribed verbatim and thematically analysed. RESULTS A pilot using MSLQ with 413 students recorded a Cronbach's alpha of 0.928 for the questionnaire. The actual study involved 457 Years 1 & 2 students. Students from both institutions are motivated by the Task Value, and they use Elaboration and Organisation strategies the most in their pre-clinical year. Three themes emerged from the qualitative analysis of this study: characteristics of strategies that promote SRL, hindrance in promoting SRL, and opportunities in promoting SRL. CONCLUSIONS Our findings indicate that students' intrinsic motivation is generally high in pre-clinical year. However, metacognition and critical thinking strategies will need to be enhanced among students. Despite knowing teaching and learning approaches could promote these strategies, many teachers are still not confident in doing so and hence training dang sharing best practices might be helpful in promoting SRL.
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Affiliation(s)
- Shuh Shing Lee
- Centre for Medical Education, Yong Loo Lin School of Medicine, National University of Singapore, 21 Lower Kent Ridge Rd, Singapore, 119077 Singapore
| | - Dujeepa D. Samarasekera
- Centre for Medical Education, Yong Loo Lin School of Medicine, National University of Singapore, 21 Lower Kent Ridge Rd, Singapore, 119077 Singapore
| | - Joong Hiong Sim
- Medical Education and Research Development Unit, Faculty of Medicine, University of Malaya, Wilayah Persekutuan, Kuala Lumpur, Malaysia
| | - Wei-Han Hong
- Medical Education and Research Development Unit, Faculty of Medicine, University of Malaya, Wilayah Persekutuan, Kuala Lumpur, Malaysia
| | - Chan Choong Foong
- Medical Education and Research Development Unit, Faculty of Medicine, University of Malaya, Wilayah Persekutuan, Kuala Lumpur, Malaysia
| | - Vinod Pallath
- Medical Education and Research Development Unit, Faculty of Medicine, University of Malaya, Wilayah Persekutuan, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Medical Education and Research Development Unit, Faculty of Medicine, University of Malaya, Wilayah Persekutuan, Kuala Lumpur, Malaysia
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Iyadorai T, Mariappan V, Vellasamy KM, Wanyiri JW, Roslani AC, Lee GK, Sears C, Vadivelu J. Prevalence and association of pks+ Escherichia coli with colorectal cancer in patients at the University Malaya Medical Centre, Malaysia. PLoS One 2020; 15:e0228217. [PMID: 31990962 PMCID: PMC6986756 DOI: 10.1371/journal.pone.0228217] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Accepted: 01/09/2020] [Indexed: 12/13/2022] Open
Abstract
Escherichia coli (E. coli) from the B2 phylogenetic group is implicated in colorectal cancer (CRC) as it possesses a genomic island, termed polyketide synthetase (pks), which codes for the synthesis of colibactin, a genotoxin that induces DNA damage, cell cycle arrest, mutations and chromosomal instability in eukaryotic cells. The aim of this study was to detect and compare the prevalence of E. coli expressing pks (pks+E. coli) in CRC patients and healthy controls followed by investigating the virulence triggered by pks+E. coli using an in-vitro model. Mucosal colon tissues were collected and processed to determine the presence of pks+E. coli. Thereafter, primary colon epithelial (PCE) and colorectal carcinoma (HCT116) cell lines were used to detect cytopathic response to the isolated pks+E. coli strains. Our results showed 16.7% and 4.3% of CRC and healthy controls, respectively were pks+E. coli. Further, PCE displayed syncytia and cell swelling and HCT116 cells, megalocytosis, in response to treatment with the isolated pks+E. coli strains. In conclusion, pks+E. coli was more often isolated from tissue of CRC patients compared to healthy individuals, and our in-vitro assays suggest these isolated strains may be involved in the initiation and development of CRC.
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Affiliation(s)
- Thevambiga Iyadorai
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Vanitha Mariappan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.,University of Malaya Centre of Proteomics Research (UMCPR), University of Malaya, Kuala Lumpur, Malaysia
| | - Kumutha Malar Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Jane Wangui Wanyiri
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - April Camilla Roslani
- Department of Surgery, University of Malaya, Kuala Lumpur, Malaysia.,University of Malaya Cancer Research Institute, Kuala Lumpur, Malaysia
| | - Goh Khean Lee
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Cynthia Sears
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.,Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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45
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Ganesh PS, Vishnupriya S, Vadivelu J, Mariappan V, Vellasamy KM, Shankar EM. Intracellular survival and innate immune evasion of Burkholderia cepacia: Improved understanding of quorum sensing-controlled virulence factors, biofilm, and inhibitors. Microbiol Immunol 2020; 64:87-98. [PMID: 31769530 DOI: 10.1111/1348-0421.12762] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 11/18/2019] [Accepted: 11/21/2019] [Indexed: 12/25/2022]
Abstract
Burkholderia cepacia complex (Bcc) are opportunistic pathogens implicated with nosocomial infections, and high rates of morbidity and mortality, especially in individuals with cystic fibrosis (CF). B. cepacia are naturally resistant to different classes of antibiotics, and can subvert the host innate immune responses by producing quorum sensing (QS) controlled virulence factors and biofilms. It still remains a conundrum as to how exactly the bacterium survives the intracellular environment within the host cells of CF patients and immunocompromised individuals although the bacterium can invade human lung epithelial cells, neutrophils, and murine macrophages. The mechanisms associated with intracellular survival in the airway epithelial cells and the role of QS and virulence factors in B. cepacia infections in cystic fibrosis remain largely unclear. The current review focuses on understanding the role of QS-controlled virulence factors and biofilms, and provides additional impetus to understanding the potentials of QS-inhibitory strategies against B. cepacia.
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Affiliation(s)
- Pitchaipillai Sankar Ganesh
- Division of Infection Biology & Medical Microbiology, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Thiruvarur, India
| | - Sivakumar Vishnupriya
- Division of Infection Biology & Medical Microbiology, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Thiruvarur, India
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Vanitha Mariappan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kumutha M Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Esaki M Shankar
- Division of Infection Biology & Medical Microbiology, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Thiruvarur, India
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Sidahmed HMA, Vadivelu J, Loke MF, Arbab IA, Abdul B, Sukari MA, Abdelwahab SI. Anti-ulcerogenic activity of dentatin from clausena excavata Burm.f. against ethanol-induced gastric ulcer in rats: Possible role of mucus and anti-oxidant effect. Phytomedicine 2019; 55:31-39. [PMID: 30668441 DOI: 10.1016/j.phymed.2018.06.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 05/22/2018] [Accepted: 06/19/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Clausena excavata Burm.f. (Rutaceae) has been used for the treatment of stomach disorders including peptic ulcer. PURPOSE In this study, we aimed to investigate dentatin isolated from C. excavata Burm.f., for anti-ulcer activity against ethanol ulcer model in rats. METHODS Gastric acid output, ulcer index, serum profile, histological evaluation using Hematoxylin and eosin (HE), periodic acid Schiff base stainings and immunohistochemical localization for heat shock proteins 70 (HSP70) were all investigated. Possible involvement of reduced glutathione (GSH), lipid peroxidation, prostaglandin E2 (PGE2), superoxide dismutase (SOD) enzymes, radical scavenging, and anti-Helicobacter pylori activity were investigated. RESULTS Dentatin showed anti-secretory activity against the pylorus ligature model and protected the gastric mucosa from ethanol ulceration, as revealed by the improved macroscopic and histological appearance. Dentatin significantly increased the gastric homogenate content of PGE2 GSH and SOD. Dentatin inhibited the lipid peroxidation as revealed by the reduced gastric content of malondialdehyde (MDA). Moreover, dentatin up-regulated HSP70 expression. However, dentatin showed insignificant anti-H. pylori activity. CONCLUSION Dentatin possesses gastro-protective activity, which could be attributed to the anti-secretory, mucus production, anti-oxidant, and HSP70 activities.
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Affiliation(s)
- Heyam Mohamed Ali Sidahmed
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Mun Fai Loke
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Ismail Adam Arbab
- Department of Chemistry, Faculty of Science, Universiti Putra Malaysia UPM, 43400 Serdang, Selangor, Malaysia
| | - Bustamam Abdul
- Department of Chemistry, Faculty of Science, Universiti Putra Malaysia UPM, 43400 Serdang, Selangor, Malaysia
| | - Mohd Aspollah Sukari
- Department of Chemistry, Faculty of Science, Universiti Putra Malaysia UPM, 43400 Serdang, Selangor, Malaysia
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Chua EG, Debowski AW, Webberley KM, Peters F, Lamichhane B, Loke MF, Vadivelu J, Tay CY, Marshall BJ, Wise MJ. Analysis of core protein clusters identifies candidate variable sites conferring metronidazole resistance in Helicobacter pylori. Gastroenterol Rep (Oxf) 2019; 7:42-49. [PMID: 30792865 PMCID: PMC6375344 DOI: 10.1093/gastro/goy048] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/19/2018] [Accepted: 09/26/2018] [Indexed: 01/10/2023] Open
Abstract
Background Metronidazole is one of the first-line drugs of choice in the standard triple therapy used to eradicate Helicobacter pylori infection. Hence, the global emergence of metronidazole resistance in Hp poses a major challenge to health professionals. Inactivation of RdxA is known to be a major mechanism of conferring metronidazole resistance in H. pylori. However, metronidazole resistance can also arise in H. pylori strains expressing functional RdxA protein, suggesting that there are other mechanisms that may confer resistance to this drug. Methods We performed whole-genome sequencing on 121 H. pylori clinical strains, among which 73 were metronidazole-resistant. Sequence-alignment analysis of core protein clusters derived from clinical strains containing full-length RdxA was performed. Variable sites in each alignment were statistically compared between the resistant and susceptible groups to determine candidate genes along with their respective amino-acid changes that may account for the development of metronidazole resistance in H. pylori. Results Resistance due to RdxA truncation was identified in 34% of metronidazole-resistant strains. Analysis of core protein clusters derived from the remaining 48 metronidazole-resistant strains and 48 metronidazole-susceptible identified four variable sites significantly associated with metronidazole resistance. These sites included R16H/C in RdxA, D85N in the inner-membrane protein RclC (HP0565), V265I in a biotin carboxylase protein (HP0370) and A51V/T in a putative threonylcarbamoyl–AMP synthase (HP0918). Conclusions Our approach identified new potential mechanisms for metronidazole resistance in H. pylori that merit further investigation.
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Affiliation(s)
- Eng-Guan Chua
- The Marshall Centre for Infectious Diseases Research and Training, University of Western Australia, Perth, Western Australia, Australia
| | - Aleksandra W Debowski
- The Marshall Centre for Infectious Diseases Research and Training, University of Western Australia, Perth, Western Australia, Australia.,School of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - K Mary Webberley
- The Marshall Centre for Infectious Diseases Research and Training, University of Western Australia, Perth, Western Australia, Australia
| | - Fanny Peters
- The Marshall Centre for Infectious Diseases Research and Training, University of Western Australia, Perth, Western Australia, Australia
| | - Binit Lamichhane
- The Marshall Centre for Infectious Diseases Research and Training, University of Western Australia, Perth, Western Australia, Australia
| | - Mun-Fai Loke
- Department of Medical Microbiology, University of Malaya, Kuala Lumpur, Wilayah Persekutuan, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, University of Malaya, Kuala Lumpur, Wilayah Persekutuan, Malaysia
| | - Chin-Yen Tay
- The Marshall Centre for Infectious Diseases Research and Training, University of Western Australia, Perth, Western Australia, Australia.,Shenzhen Dapeng New District Kuichong People Hospital, Shenzhen, Guangdong, China
| | - Barry J Marshall
- The Marshall Centre for Infectious Diseases Research and Training, University of Western Australia, Perth, Western Australia, Australia.,Shenzhen Dapeng New District Kuichong People Hospital, Shenzhen, Guangdong, China.,UM Marshall Centre, University of Malaya, Kuala Lumpur, Wilayah Persekutuan, Malaysia
| | - Michael J Wise
- The Marshall Centre for Infectious Diseases Research and Training, University of Western Australia, Perth, Western Australia, Australia.,School of Computer Science and Software Engineering, University of Western Australia, Perth, Western Australia, Australia
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48
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Ram M. R, Teh X, Rajakumar T, Goh KL, Leow AHR, Poh BH, Mariappan V, Shankar EM, Loke MF, Vadivelu J. Polymorphisms in the host CYP2C19 gene and antibiotic-resistance attributes ofHelicobacter pyloriisolates influence the outcome of triple therapy. J Antimicrob Chemother 2018; 74:11-16. [DOI: 10.1093/jac/dky401] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 09/05/2018] [Indexed: 12/11/2022] Open
Affiliation(s)
- Ravishankar Ram M.
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, Branišovská 31, České Budějovice (Budweis), Czech Republic
| | - Xinsheng Teh
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Tamayanthi Rajakumar
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Khean Lee Goh
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Alex Hwong Ruey Leow
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Bee Hoon Poh
- BP Diagnostic Centre Sdn Bhd, Ipoh, Perak, Malaysia
| | - Vanitha Mariappan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Esaki M Shankar
- Division of Infection Biology and Medical Microbiology, Department of Life Sciences, Central University of Tamil Nadu (CUTN), Thiruvarur, India
| | - Mun Fai Loke
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- School of Life Sciences & Chemical Technology, Ngee Ann Polytechnic, Singapore, Singapore
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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49
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Leow AHR, Azmi AN, Loke MF, Vadivelu J, Graham DY, Goh KL. Optimizing first line 7-day standard triple therapy for Helicobacter pylori eradication: Prolonging treatment or adding bismuth: which is better? J Dig Dis 2018; 19:674-677. [PMID: 30307122 DOI: 10.1111/1751-2980.12679] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 08/19/2018] [Accepted: 10/09/2018] [Indexed: 12/11/2022]
Abstract
OBJECTIVE The 7-day standard triple therapy (STT) gives unacceptablly low eradication rates of Helicobacter pylori (H. pylori). We aimed to examine whether extending STT from 7 days to 14 days or adding a bismuth compound to a 7-day STT would result in better eradication rates. METHODS H. pylori-positive patients were assigned to Group A (7-day STT; rabeprazole 20 mg twice daily, amoxicillin 1 g twice daily, and clarithromycin 500 mg twice daily, for 7 days), Group B (7-day STT with bismuth; rabeprazole 20 mg twice daily, amoxicillin 1 g twice daily, clarithromycin 500 mg twice daily and bismuth subcitrate 240 mg twice daily, for 7 days) and Group C (14-day STT; rabeprazole 20 mg twice daily, amoxicillin 1 g twice daily, and clarithromycin 500 mg twice daily for 14 days). Eradication was tested using 13 C-UBT at least 4 weeks after the completion of therapy. RESULTS A total of 364 patients were recruited. In the intention-to-treat analysis, eradication rates were 79.3% (96/121; 95% confidence interval [CI] 71.3-85.6%) for 7-day STT, 81.7% (98/120; 95% CI 73.8-87.6%) for 7-day STT with bismuth, and 88.6% (109/123; 95% CI 81.8-93.1%) for 14-day STT, respectively. Statistical significance was achieved between the 7-day and the 14-day STT treatment (P = 0.048). CONCLUSIONS Adding bismuth to the 7-day STT did not result in an increase in the eradication rate. Extending the STT to 14 days, however, achieved a significantly higher eradication rate. Nevertheless, this did not achieve the targeted 90% eradication rate on intention-to-treat analysis.
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Affiliation(s)
- Alex H-R Leow
- Division of Gastroenterology and Hepatology, Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Ahmad N Azmi
- Faculty of Medicine and Health Sciences, University Science Islam Malaysia, Kuala Lumpur, Malaysia
| | - Mun-Fai Loke
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - David Y Graham
- Michael E. DeBakey Veterans Health Administration Center, Baylor College of Medicine, Houston, Texas, USA
| | - Khean-Lee Goh
- Division of Gastroenterology and Hepatology, Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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50
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Rafieerad AR, Bushroa AR, Amiri A, Kalaiselvam K, Vellasamy KM, Vadivelu J. Antibacterial biocompatible arginine functionalized mono-layer graphene: No more risk of silver toxicity. J Hazard Mater 2018; 360:132-140. [PMID: 30099356 DOI: 10.1016/j.jhazmat.2018.07.107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 07/18/2018] [Accepted: 07/30/2018] [Indexed: 06/08/2023]
Abstract
Antibacterial ability is vital in biological approaches as well as functional biomaterials. Besides, cytocompatibility aspect of biologic media, tissue and organs is always concern for appropriate synthesis. From the past, metallic/oxide phases of silver (Ag) material in various macro, micro or nano configurations have been widely used for antibacterial targets. While, background of Ag toxicity within particle, film and composites is posing gradual ion release affected by molecular bounding. Recent researches conducted to control, optimize and neutralize Ag limitations finding the benefits of ideal (∼ 100%) mediation against both Gram-negative and Gram-positive bacteria. Whereas, non-degradable releases history is still a challenge and its longer accumulation may cause to disrupt biostructures and disease risk. Thus, facile development of large-area organic materials with switchable bacteria toxicity and normal cell compatibility function is interesting for concerned approaches. Here, smart positively-charged stable arginine amino acid incorporated mono layer graphene (Arg-EMGr) nanobiocomposite introduced as useful antibacterial and safe bactericidal agent competitive with Ag direct. The immunity characteristic versus Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) comparably assessed with graphene oxide (GO) and different concentrations GO-AgNPs morphology. As cell viability matter, 1,3,5,7-days vitro culture assay shown attachment proliferation and cytotoxicity due to short interaction.
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Affiliation(s)
- A R Rafieerad
- St. Boniface Hospital Research Centre, Department of Physiology, University of Manitoba, Winnipeg, Canada; Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia; Centre of Advanced Manufacturing and Material Processing (AMMP), Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - A R Bushroa
- Centre of Advanced Manufacturing and Material Processing (AMMP), Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia; Department of Mechanical Engineering, Faculty of Engineering, University of UCLA, Los Angeles, CA 90032, United States.
| | - Ahmad Amiri
- Department of Mechanical Engineering, Texas A&M University, College Station, Texas 77843, United States.
| | - K Kalaiselvam
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - K M Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - J Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
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