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Sokal A, Royer G, Esposito-Farese M, Clermont O, Condamine B, Laouénan C, Lefort A, Denamur E, de Lastours V. Clinical and Bacteriological Specificities of Escherichia coli Bloodstream Infections From Biliary Portal of Entries. J Infect Dis 2024; 229:1679-1687. [PMID: 38214565 DOI: 10.1093/infdis/jiad586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 12/13/2023] [Accepted: 12/18/2023] [Indexed: 01/13/2024] Open
Abstract
BACKGROUND Escherichia coli is frequently responsible for bloodstream infections (BSIs). Among digestive BSIs, biliary infections appear to be less severe. Respective roles of host factors, bacterial determinants (phylogroups, virulence, and antibiotic resistance), and portal of entry on outcome are unknown. METHODS Clinical characteristics and prognosis of 770 episodes of E coli BSI were analyzed and isolates sequenced (Illumina technology) comparing phylogroups, multilocus sequence type, virulence, and resistance gene content. BSI isolates were compared with 362 commensal E coli from healthy subjects. RESULTS Among 770 episodes, 135 were biliary, 156 nonbiliary digestive, and 479 urinary. Compared to urinary infections, BSIs of digestive origin occurred significantly more in men, comorbid, and immunocompromised patients. Digestive portal of entry was significantly associated with septic shock and death. Among digestive infections, patients with biliary infections were less likely to die (P = .032), despite comparable initial severity. Biliary E coli resembled commensals (phylogroup distribution, sequence type, and few virulence-associated genes) whereas nonbiliary digestive and urinary strains carried many virulence-associated genes. CONCLUSIONS Escherichia coli strains responsible for biliary infections exhibit commensal characteristics and are associated with lower mortality rates, despite similar initial severity, than other digestive BSIs. Biliary drainage in addition to antibiotics in the management of biliary infections may explain improved outcome.
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Sa'ari CZ, Chik H, Syed Muhsin SB, Zainuddin SI, Abdul Aziz NA, Mohammad Jodi KH, Saari CZ, Muhamad Shukri AS, Karman S, Surip AG. Needs Analysis for The Development of a Manual in Palliative Care for Malaysia: An Islamic Psychospiritual Approach. JOURNAL OF RELIGION AND HEALTH 2024:10.1007/s10943-024-02073-w. [PMID: 38874714 DOI: 10.1007/s10943-024-02073-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/29/2024] [Indexed: 06/15/2024]
Abstract
This study explicates an Islamic approach to palliative care based on the results of a needs analysis regarding the development of an Islamic psychospiritual manual of palliative care alongside related elements. This article represents the first phase of a three-phase study using the design and development research (DDR) approach developed by Richey and Klein to study for design and development of manual either needed or otherwise. This project is a quantitative study that uses purposive sampling through a questionnaire instrument to investigate 210 participants from the general population in Malaysia that have experience in taking care of terminally ill patients. The findings of the study indicated that the majority of participants agreed with the development of an Islamic psychospiritual manual with mean values (x̅) of 4.57 and 4.66. Concurrently, the findings showed that the hierarchy of emphasis in terms of the elements to be included in the manual starts with emotional support, which exhibited the highest mean rate (x̅), followed by faith in God, spiritual and religious support, self and physical management, trauma management and social support. The correlations indicated that all the elements to be included in the manual were significant.
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Elsayed SA, Elnabky IM, Aboelnga MM, El-Hendawy AM. Palladium(ii), platinum(ii), and silver(i) complexes with 3-acetylcoumarin benzoylhydrazone Schiff base: Synthesis, characterization, biomolecular interactions, cytotoxic activity, and computational studies. RSC Adv 2024; 14:19512-19527. [PMID: 38895519 PMCID: PMC11184370 DOI: 10.1039/d4ra02738h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Accepted: 06/02/2024] [Indexed: 06/21/2024] Open
Abstract
New Pd(ii) (C1), Pt(ii) (C2), and Ag(i) (C3) complexes derived from 3-acetylcoumarin benzoylhydrazone (HL) Schiff base were synthesized and characterized by FTIR, 1H NMR, UV-visible spectroscopies along with elemental analysis (C, H, N), magnetic, molar conductivity measurements, and DFT calculations. The obtained results suggested that the ligand had different behaviors in the complexes: mono-negative tridentate (C1) and neutral tridentate (C2) as an ONO-donor and neutral bidentate (C3) as an ON-donor. Quantum chemistry calculations were performed to validate the stability of the suggested geometries and indicated that all the complexes possess tetra-coordinated metal ions. The binding affinity of all the compounds toward calf thymus (ctDNA), yeast (tRNA), and bovine serum albumin (BSA) was evaluated by absorption/emission spectral titration studies, which revealed the intercalative binding to ctDNA and tRNA and static binding upon complex formation with BSA. Molecular insights into the binding affinity of the characterized complexes were provided through conducting molecular docking analysis. Moreover, the cytotoxic activity (in vitro) of the compounds was screened against human cancerous cell lines and a non-cancerous lung fibroblast (WI38) one using cis-platin as a reference drug. The IC50 and selective index (SI) values indicated the higher cytotoxic activity of all the metal complexes compared to their parent ligand. Among all the compounds, the complex C2 showed the highest activity. These results confirmed the improvement of the anticancer activity of the ligand by incorporating the metal ions. In addition, flow cytometry results showed that complexes C1 and C2 induced cell cycle arrest at S and G1/S, respectively.
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Al-Taani GM, Muflih SM, Al-Azzam SI, Alzoubi KH. Costs saved and avoided from pharmacist interventions to address drug-related problems identified from outpatient clinics in Jordan. PLoS One 2024; 19:e0302287. [PMID: 38843244 PMCID: PMC11156302 DOI: 10.1371/journal.pone.0302287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 04/02/2024] [Indexed: 06/09/2024] Open
Abstract
BACKGROUND The pharmacist plays an essential role in identifying and managing drug-related problems. The aim of this research was to assess the costs avoided by clinical pharmacist interventions to resolve drug-related problems. RESEARCH DESIGN AND METHODS Clinical pharmacists identified drug-related problems and interventions to address them in consecutive outpatients visiting internal medicine clinics at major teaching and public hospitals in Jordan from September 2012 to December 2013. The costs avoided by each intervention to address drug-related problems were collected from the literature. The collected data were used to calculate the overall cost saved and avoided by the interventions implemented to address the identified drug-related problems, adopting a Jordanian healthcare system perspective. RESULTS A total of 2747 patients were enrolled in the study. Diagnostic interventions, such as the need for additional diagnostic testing, were employed in 95.07% of the 13935 intervention to address the drug-related problem "Miscellaneous" which was the most frequent drug-related problems. Other common drug-related problems categories included inappropriate knowledge (n = 6972), inappropriate adherence (4447), efficacy-related drug-related problem (3395) and unnecessary drug therapy (1082). The total cost avoided over the research period was JOD 1418720 per month and total cost saved over the study period was JOD 17250.204. Drug-related problems were associated the number of prescription medications (odds ratio = 1.105; 95% confidence interval = 1.069-1.142), prescribed gastrointestinal drugs (3.485; 2.86-4.247), prescribed antimicrobials (3.326; 1.084-10.205), and prescribed musculoskeletal drugs (1.385; 1.011-1.852). CONCLUSIONS The study revealed that pharmacists have provided cognitive input to rationalize and optimize the medication use and prevent errors, that led to the reported projected avoided and saved expenditures via various interventions to address drug-related problems. This highlights the added economic impact to the clinical impact of drug-related problems on patients and the healthcare system. The high prevalence and cost of drug-related problems offer strong rationale for pharmacists to provide more vigilant intervention to improve patient outcomes while maintaining cost effectiveness.
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Farahat DS, Dang M, El-Fallal A, Badr N, Ma PX. Poly(N-isopropylacrylamide) based smart nanofibrous scaffolds for use as on-demand delivery systems for oral and dental tissue regeneration. J Biomed Mater Res A 2024; 112:852-865. [PMID: 38192179 DOI: 10.1002/jbm.a.37664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 09/06/2023] [Accepted: 12/18/2023] [Indexed: 01/10/2024]
Abstract
Stimuli-responsive domains capable of releasing loaded molecules, "on-demand," have garnered increasing attention due to their enhanced delivery, precision targeting, and decreased adverse effects. The development of an on-demand delivery system that can be easily triggered by dental clinicians might have major roles in dental and oral tissue engineering. A series of random graft poly(NIPAm-co-HEMA-Lactate) copolymers were synthesized using 95:5, 85:5, 60:40, and 40:60 ratios of thermosensitive NIPAm and HEMA-poly lactate respectively then electrospun to produce nanofibrous scaffolds loaded with bovine serum albumin (BSA). Cumulative BSA release was assessed at 25C and 37°C. To appraise the use of scaffolds as on-demand delivery systems, they were subjected to thermal changes in the form cooling and warming cycles during which BSA release was monitored. To confirm the triggered releasing ability of the synthesized scaffolds, the copolymer made with 60% NIPAm was selected, based on the results of the release tests, and loaded with bone morphogenetic protein-2 (BMP-2). The loaded scaffolds were placed with mesenchymal-like stem cells (iMSCs) derived from induced pluripotent stem cells (iPSCs), and subjected to temperature alterations. Then, the osteogenic differentiation of iMSCs, which might have resulted from the released protein, was evaluated after 10 days by analyzing runt-related transcription factor 2 (RUNX-2) osteogenic gene expression by the cells using real-time quantitative polymerase chain reaction (qRT-PCR). BSA release profiles showed a burst release at the beginning followed by a more linear pattern at 25°C, and a much slower release at 37°C. The release also decreased when the PNIPAm content decreased in the scaffolds. Thermal triggering led to a step-like release pattern in which the highest release was reported 30 min through the warming cycles. The iMSCs cultivated with scaffolds loaded with BMP-2 and exposed to temperature alteration showed significantly higher RUNX-2 gene expression than cells in the other experimental groups. The synthesized scaffolds are thermo-responsive and could be triggered to deliver biological biomolecules to be used in oral and dental tissue engineering. Thermal stimuli could be simulated by dental clinicians using simple means of cold therapy, for example, cold packs in intraoral accessible sites for specified times.
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Ang BJ, Suardi N, Abduraman MA. Exploring differentiation-dependent responses to 532 nm green laser photobiomodulation in SHSY5Y neuroblastoma cells. Lasers Med Sci 2024; 39:147. [PMID: 38822930 DOI: 10.1007/s10103-024-04102-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 05/27/2024] [Indexed: 06/03/2024]
Abstract
Photobiomodulation (PBM) holds promise as a therapy modality, but its applicability is hindered by the lack of a quantitative model to predict the optimal dose for all forms of PBM. This study investigated the optimal PBM parameters for 532 nm green laser irradiation on SHSY5Y neuroblastoma cells, a commonly used in vitro model for neurodegenerative disease studies. A two-tailed, two sample t-test with equal variance was used to obtain the p-values and statistical significance. There are 3 sets of parameters showing significant ( p < 0 . 01 ) positive percentage biostimulation. 160 m W , 15 m i n produce a percentage biostimulation of ( 9 ± 10 ) % ; 180 m W , 5 m i n produce a percentage biostimulation of ( 19 ± 7 ) % ; and ( 200 m W , 5 m i n ) produce a percentage biostimulation of ( 9 ± 2 ) % . The highest significant ( p < 0 . 01 ) percentage bioinhibition observed is for 220 m W , 15 m i n (dose: 1008 J / c m 2 ) producing a bioinhibition of ( 54 ± 1 ) % . After identifying several parameters that produce noticeable photobiological effects (biostimulation and bioinhibition), this study compared the reaction of undifferentiated and differentiated SHSY5Y cells to laser irradiation and found that undifferentiated SHSY5Y cells shows greater photobiological effect from 532 nm laser irradiation ( p < 0 . 01 ) . This study demonstrated the differentiation-dependant photobiological effect of SHSY5Y in 532 nm laser PBM. This shows that considerations on the differentiation state of cells is important in PBM studies. The hypothesis of difference in intracellular reactive oxygen species (ROS) accumulation from laser irradiation can serve as a versatile explanation of the observed difference in photobiological effect. Further investigation into the role of ROS as a mediator of various photobiological effects from laser of different wavelengths is warranted.
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Boulard P, Azzopardi N, Levard R, Cornec JM, Lamamy J, Prieur B, Demattei MV, Watier H, Gatault P, Gouilleux-Gruart V. Albumin influences leucocyte FcRn expression in the early days of kidney transplantation. Clin Exp Immunol 2024; 216:307-317. [PMID: 38353127 PMCID: PMC11097912 DOI: 10.1093/cei/uxae011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 12/28/2023] [Accepted: 02/08/2024] [Indexed: 05/18/2024] Open
Abstract
FcRn, a receptor originally known for its involvement in IgG and albumin transcytosis and recycling, is also important in the establishment of the innate and adaptive immune response. Dysregulation of the immune response has been associated with variations in FcRn expression, as observed in cancer. Recently, a link between autophagy and FcRn expression has been demonstrated. Knowing that autophagy is strongly involved in the development of reperfusion injury in kidney transplantation and that albuminemia is transiently decreased in the first 2 weeks after transplantation, we investigated variations in FcRn expression after kidney transplantation. We monitored FcRn levels by flow cytometry in leukocytes from 25 renal transplant patients and considered parameters such as albumin concentrations, estimated glomerular filtration rate, serum creatinine, serum IgG levels, and ischaemia/reperfusion time. Two groups of patients could be distinguished according to their increased or non-increased FcRn expression levels between days 2 and 6 (d2-d6) post-transplantation. Leukocyte FcRn expression at d2-d6 was correlated with albumin concentrations at d0-d2. These results suggest that albumin concentrations at d0-d2 influence FcRn expression at d2-d6, raising new questions about the mechanisms underlying these original observations.
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Ooi TC, Rivan NFM, Shahar S, Rajab NF, Ismail M, Singh DKA. Predictors, Protective Factors, and Adverse Outcomes of Joint Pain among Malaysian Community-Dwelling Older Adults: Findings from the LRGS-TUA Longitudinal Study. J Clin Med 2024; 13:2854. [PMID: 38792397 PMCID: PMC11122189 DOI: 10.3390/jcm13102854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/09/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
Background: Joint pain has been recognized as one of the major causes of limitations in mobility, functional decline, and consequently declined quality of life in older adults. Hence, this study aimed to identify the predictors, protective factors, and adverse outcomes of joint pain in community-dwelling older adults. Methods: In this Long-term Research Grant Scheme-Towards Useful Ageing (LRGS-TUA) longitudinal study, a total of 1005 older participants aged 60 years and above who were successfully followed up after five years were included in the analysis. The participants self-reported their joint pain status at baseline and during the fifth year. Subsequently, the baseline characteristics were used to predict changes in joint pain status. Adverse outcomes related to joint pain were evaluated based on the participants' joint pain statuses. Results: Results showed that being female, having diabetes mellitus, and higher body mass index were associated with the incidence of joint pain. Meanwhile, increased intake of pantothenic acid and higher levels of blood albumin levels were associated with recovery from joint pain. Participants with persistent joint pain at baseline and follow-up showed higher levels of depression and disability compared to individuals who never experience any joint pain. However, participants who had recovered from joint pain did not differ significantly from those without joint pain at baseline and follow-up in these measures. Conclusions: By identifying the modifiable risk factors, factors associated with recovery, and adverse outcomes related to joint pain, this study adds to current evidence that may contribute to further management strategies for joint pain in older adults.
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Sahimin N, Low ZX, Hassandarvish P, Mohd Hanapi IR, Mohd Zain SN, Yahaya H, Abu Bakar S. Seroprevalence of dengue and chikungunya viruses among urban refugees in Klang Valley, Malaysia. Trans R Soc Trop Med Hyg 2024; 118:328-335. [PMID: 38226501 DOI: 10.1093/trstmh/trad097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 02/26/2023] [Accepted: 12/24/2023] [Indexed: 01/17/2024] Open
Abstract
BACKGROUND Mosquito-borne diseases pose a significant global public health threat, with Malaysia's Klang Valley experiencing numerous outbreaks in densely populated urban areas. METHODS This study aimed to estimate the seroprevalence of anti-dengue and anti-chikungunya antibodies among urban refugees in the Klang Valley, Malaysia, and identify associated risk factors. RESULTS High seroprevalence of anti-dengue immunoglobulin G (IgG) and IgM (60.0% [confidence interval {CI} 55.39 to 64.48] and 9.2% [CI 6.77 to 12.25], respectively) were observed among refugees >18 years of age (χ22=11.720, p=0.003), Kachin ethnicity (χ28=72.253, p<0.001), without formal education (χ21=3.856, p=0.050), homes near waste disposal sites (χ21=10.378, p=0.001) and refugees who have experienced flooding (χ21=5.460, p=0.019). Meanwhile, the overall seroprevalence of anti-chikungunya IgG and IgM was 9.7% (CI 7.15 to 12.73) and 10.8% (CI 8.09 to 13.93), respectively, with ages 12-18 years (χ22=6.075, p=0.048), Rohingya ethnicity (χ28=31.631, p<0.001) and homes close to waste disposal sites (χ21=3.912, p=0.048) being significant risk factors. Results showed a link to poor environmental living conditions, with an increase in the vector population with higher availability of breeding sites and thus exposure to dengue and chikungunya virus. CONCLUSIONS Health education among the community is the key to disease prevention, as there are no specific antiviral drugs for treatment and limited vaccine availability.
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Abdelkarem FM, Assaf HK, Mostafa YA, Mahdy A, Hussein MF, Ross SA, Mohamed NM. Antiviral activity of sulphated specialized metabolites from sea urchin Clypeaster humilis: in vitro and in silico studies. RSC Adv 2024; 14:14185-14193. [PMID: 38690113 PMCID: PMC11058476 DOI: 10.1039/d4ra01966k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 04/05/2024] [Indexed: 05/02/2024] Open
Abstract
Chemical investigations of the sea urchin Clypeaster humilis has led to separation of twelve compounds including one new sulfonic acid derivative (7R) tridec-1-en-7-yl hydrogen sulphate (1), first isolated from natural source, pyridine-3-yl methane sulfonate (2), and first isolated from marine organisms, boldine (12), in addition to nine known compounds (3-11), which were isolated for the first time from the genus Clypeaster. Their structures were elucidated based on spectroscopic analyses (1D and 2D NMR), HR-ESI-MS as well as comparison with the previously reported data. The antiviral activity of the crude extract and sulphated compounds were evaluated using MTT colorimetric assay against Coxsackie B4 virus. The crude extract and compound 1 showed very potent antiviral activity with a percentage of inhibition equal to 89.7 ± 0.53% and 86.1 ± 0.92%, respectively. Results of the molecular docking analysis of the isolated compounds within Coxsackie Virus B4 (COX-B4) X-ray crystal structure and quantum chemical calculation for three sulphated compounds are in a consistent adaptation with the in vitro antiviral results. The pharmacokinetic properties (ADME) of isolated compounds were determined.
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Al-Hinai TZS, Mackay CL, Fry SC. Fruit softening: evidence for rhamnogalacturonan lyase action in vivo in ripe fruit cell walls. ANNALS OF BOTANY 2024; 133:547-558. [PMID: 38180460 PMCID: PMC11037484 DOI: 10.1093/aob/mcad197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/02/2024] [Indexed: 01/06/2024]
Abstract
BACKGROUND AND AIMS The softening of ripening fruit involves partial depolymerization of cell-wall pectin by three types of reaction: enzymic hydrolysis, enzymic elimination (lyase-catalysed) and non-enzymic oxidative scission. Two known lyase activities are pectate lyase and rhamnogalacturonan lyase (RGL), potentially causing mid-chain cleavage of homogalacturonan and rhamnogalacturonan-I (RG-I) domains of pectin respectively. However, the important biological question of whether RGL exhibits action in vivo had not been tested. METHODS We developed a method for specifically and sensitively detecting in-vivo RGL products, based on Driselase digestion of cell walls and detection of a characteristic unsaturated 'fingerprint' product (tetrasaccharide) of RGL action. KEY RESULTS In model experiments, potato RG-I that had been partially cleaved in vitro by commercial RGL was digested by Driselase, releasing an unsaturated tetrasaccharide ('ΔUA-Rha-GalA-Rha'), taken as diagnostic of RGL action. This highly acidic fingerprint compound was separated from monosaccharides (galacturonate, galactose, rhamnose, etc.) by electrophoresis at pH 2, then separated from ΔUA-GalA (the fingerprint of pectate lyase action) by thin-layer chromatography. The 'ΔUA-Rha-GalA-Rha' was confirmed as 4-deoxy-β-l-threo-hex-4-enopyranuronosyl-(1→2)-l-rhamnosyl-(1→4)-d-galacturonosyl-(1→2)-l-rhamnose by mass spectrometry and acid hydrolysis. Driselase digestion of cell walls from diverse ripe fruits [date, sea buckthorn, cranberry, yew (arils), mango, plum, blackberry, apple, pear and strawberry] yielded the same fingerprint compound, demonstrating that RGL had been acting in vivo in these fruits prior to harvest. The 'fingerprint' : (galacturonate + rhamnose) ratio in digests from ripe dates was approximately 1 : 72 (mol/mol), indicating that ~1.4 % of the backbone Rha→GalA bonds in endogenous RG-I had been cleaved by in-vivo RGL action. CONCLUSIONS The results provide the first demonstration that RGL, previously known from studies of fruit gene expression, proteomic studies and in-vitro enzyme activity, exhibits enzyme action in the walls of soft fruits and may thus be proposed to contribute to fruit softening.
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Wong SK. Glycogen Synthase Kinase-3 Beta (GSK3β) as a Potential Drug Target in Regulating Osteoclastogenesis: An Updated Review on Current Evidence. Biomolecules 2024; 14:502. [PMID: 38672518 PMCID: PMC11047881 DOI: 10.3390/biom14040502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 04/28/2024] Open
Abstract
Glycogen synthase kinase 3-beta (GSK3β) is a highly conserved protein kinase originally involved in glucose metabolism, insulin activity, and energy homeostasis. Recent scientific evidence demonstrated the significant role of GSK3β in regulating bone remodelling through involvement in multiple signalling networks. Specifically, the inhibition of GSK3β enhances the conversion of osteoclast progenitors into mature osteoclasts. GSK3β is recognised as a pivotal regulator for the receptor activator of nuclear factor-kappa B (RANK)/receptor activator of nuclear factor-kappa B ligand (RANKL)/osteoprotegerin (OPG), phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT), nuclear factor-kappa B (NF-κB), nuclear factor-erythroid 2-related factor 2 (NRF2)/Kelch-like ECH-associated protein 1 (KEAP1), canonical Wnt/beta (β)-catenin, and protein kinase C (PKC) signalling pathways during osteoclastogenesis. Conversely, the inhibition of GSK3β has been shown to prevent bone loss in animal models with complex physiology, suggesting that the role of GSK3β may be more significant in bone formation than bone resorption. Divergent findings have been reported regarding the efficacy of GSK3β inhibitors as bone-protecting agents. Some studies demonstrated that GSK3β inhibitors reduced osteoclast formation, while one study indicated an increase in osteoclast formation in RANKL-stimulated bone marrow macrophages (BMMs). Given the discrepancies observed in the accumulated evidence, further research is warranted, particularly regarding the use of GSK3β silencing or overexpression models. Such efforts will provide valuable insights into the direct impact of GSK3β on osteoclastogenesis and bone resorption.
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Ismail UN, Azlan CA, Khairullah S, Azman RR, Omar NF, Md Shah MN, Jackson N, Ng KH. Marrow Fat-Cortical Bone Relationship in β-Thalassemia: A Study Using MRI. J Magn Reson Imaging 2024. [PMID: 38556790 DOI: 10.1002/jmri.29366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 04/02/2024] Open
Abstract
BACKGROUND Growing evidence suggests that marrow adipocytes play an active role in the regulation of bone metabolism and hematopoiesis. However, research on the relationship between bone and fat in the context of hematological diseases, particularly β-thalassemia, remains limited. PURPOSE To investigate the relationship between marrow fat and cortical bone thickness in β-thalassemia and to identify key determinants influencing these variables. STUDY TYPE Prospective. SUBJECTS Thirty-five subjects in four subject groups of increasing disease severity: 6 healthy control (25.0 ± 5.3 years, 2 male), 4 β-thalassemia minor, 13 intermedia, and 12 major (29.1 ± 6.4 years, 15 male). FIELD STRENGTH/SEQUENCE 3.0 T, 3D fast low angle shot sequence and T1-weighted turbo spin echo. ASSESSMENT Analyses on proton density fat fraction (PDFF) and R2* values in femur subregions (femoral head, greater trochanter, intertrochanteric, diaphysis, distal) and cortical thickness (CBI) of the subjects' left femur. Clinical data such as age, sex, body mass index (BMI), and disease severity were also included. STATISTICAL TESTS One-way analysis of variance (ANOVA), mixed ANOVA, Pearson correlation and multiple regression. P-values <0.05 were considered significant. RESULTS Bone marrow PDFF significantly varied between the femur subregions, F(2.89,89.63) = 44.185 and disease severity, F(1,3) = 12.357. A significant interaction between subject groups and femur subregions on bone marrow PDFF was observed, F(8.67,89.63) = 3.723. Notably, a moderate positive correlation was observed between PDFF and CBI (r = 0.33-0.45). Multiple regression models for both PDFF (R2 = 0.476, F(13,151) = 10.547) and CBI (R2 = 0.477, F(13,151) = 10.580) were significant. Significant predictors for PDFF were disease severity (βTMi = 0.36, βTMa = 0.17), CBI (β = 0.24), R2* (β = -0.32), and height (β = -0.29) while for CBI, the significant determinants were sex (β = -0.27), BMI (β = 0.55), disease severity (βTMi = 2.15), and PDFF (β = 0.25). DATA CONCLUSION This study revealed a positive correlation between bone marrow fat fraction and cortical bone thickness in β-thalassemia with varying disease severity, potentially indicating a complex interplay between bone health and marrow composition. EVIDENCE LEVEL 2 TECHNICAL EFFICACY: Stage 3.
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Bala GA, Bery AA, Gnapragasan J, Akingboye AS. Development of novel resistivity-chargeability statistical relationships for subsurface characterization at Langkawi, Kedah. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-32867-0. [PMID: 38532213 DOI: 10.1007/s11356-024-32867-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 03/07/2024] [Indexed: 03/28/2024]
Abstract
The significance of resistivity-chargeability relationships has been acknowledged and applied in various geologic terrains and different environmental conditions. However, there remains an underexplored opportunity to fully utilize these methods in complex geological terrains with a mixture of granitic and sedimentary rocks where empirical relationships have not been established. Such discoveries are crucial for accurately delineating petrophysical and geomechanical properties, which are essential in addressing urgent environmental concerns like landslides, foundation collapse, groundwater shortages, and pollution. To address this research gap, a novel approach was employed: resistivity-chargeability data with simple linear regression modeling. The study focused on developing resistivity-chargeability relationships specifically tailored for tropical granitic environments, using a typical example from Kedah Langkawi, Malaysia. The regions are characterized by complex geological features, ruggedness, and irregular progressive weathering and fracturing of subsurface strata, making the task challenging. Despite these complexities, the study successfully derived an efficient resistivity-chargeability empirical relation that correlates resistivity and chargeability. The derived empirical relationship exhibited high accuracy, surpassing 87%, in predicting chargeability from resistivity datasets or vice versa. This achievement holds great promise in promptly and accurately addressing environmental issues specific to the target region under study. By utilizing this novel resistivity-chargeability relationship, geoscientists, engineers, and environmental practitioners can make informed decisions and effectively manage environmental challenges in these regions, especially during the pre-development stage.
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Salaish Kumar S, Mhd Jalil AM, Hussin N, Mat Daud Z'A, Ismail A. Effects of flavanols and procyanidins-rich cocoa consumption on metabolic syndrome: an update review (2013-2023). Biosci Biotechnol Biochem 2024; 88:352-360. [PMID: 38285609 DOI: 10.1093/bbb/zbae011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 01/12/2024] [Indexed: 01/31/2024]
Abstract
Studies indicated that cocoa-based products effectively mitigate the risks associated with metabolic syndrome (MetS), however, the effect varies based on cocoa types, dosages, and study durations. This review aimed to determine the flavanol-rich cocoa consumption on MetS outcomes within the last decade (2013-2023), adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Seven randomized-controlled trials (RCTs) used cocoa-based products containing 0.3-1680 mg flavanol monomers and 3.5-1270 mg procyanidins. Cocoa-based products beneficially reduced glycemic response, blood pressure and lipid profiles. However, this review highlights little evidence pinpointing the best cocoa products type and required dosage for the observed effects. Further intervention aiming to improve MetS should justify the selection and concentration of flavanols (monomers and procyanidins). A robust study design should consider registering the trials before study commencement, consider multicenter RCT trials, and adjust for potential covariates that might "masked" the outcomes.
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Kadi M, Berraouaan A, Driouech M, Ziyyat A, Mekhfi H, Bnouham M, Legssyer A. Computational Evaluation of Bioactive Compounds from Dysphania ambrosioides Leaves. Chem Biodivers 2024; 21:e202301527. [PMID: 38253787 DOI: 10.1002/cbdv.202301527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 01/04/2024] [Accepted: 01/22/2024] [Indexed: 01/24/2024]
Abstract
Dysphania ambrosioides has been reported to have many medicinal properties, due to its possession of a multitude of biologically active molecules contained in its leaves. However, very few studies have been reported to evaluate their pharmacological properties. Consequently, in the present study, many computational tools have been performed to predict drug similarity and ADMET properties. Besides, the inhibitory potential of D.ambrosioides major compounds against Bacterial, Fungal and cardiovascular main receptor targets has been investigated. This study suggests that Carvone oxide, 5-Isopropenyl-2-Methylenecyclohexanol, and Caryophyllene oxide were the most active molecules belonging to D. ambrosioides Leaves, possessing drug-likeness with satisfactory bioactivity scores, having good pharmacokinetic values. Metabolism and toxicities were further studied using FAME3, GLORY, and pred-hERG. Slight cardiotoxicity and cytotoxicity were predicted, respectively, for Caryophyllene oxide and Carvone oxide, 5-Isopropenyl-2-Methylenecyclohexanol. Good inhibitory activities of the three compounds against Bacterial, Fungal, and Cardiovascular receptor targets. Hence, this is a comprehensive in silico approach to evaluate D.ambrosioides Leaves main phytocompounds in the background of its potential in future drug development.
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Gunter NV, Teh SS, Jantan I, Law KP, Morita H, Mah SH. Natural xanthones as modulators of the Nrf2/ARE signaling pathway and potential gastroprotective agents. Phytother Res 2024. [PMID: 38372084 DOI: 10.1002/ptr.8160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/22/2024] [Accepted: 01/31/2024] [Indexed: 02/20/2024]
Abstract
Oxidative stress is implicated in the initiation, pathogenesis, and progression of various gastric inflammatory diseases (GID). The prevalence of these diseases remains a concern along with the increasing risks of adverse effects in current clinical interventions. Hence, new gastroprotective agents capable of inhibiting oxidative stress by modulating cellular defense systems such as the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway are critically needed to address these issues. A candidate to solve the present issue is xanthone, a natural compound that reportedly exerts gastroprotective effects via antioxidant, anti-inflammatory, and cytoprotective mechanisms. Moreover, xanthone derivatives were shown to modulate the Nrf2/ARE signaling pathway to counter oxidative stress in both in vitro and in vivo models. Thirteen natural xanthones have demonstrated the ability to modulate the Nrf2/ARE signaling pathway and have high potential as lead compounds for GID as indicated by their in vivo gastroprotective action-particularly mangiferin (2), α-mangostin (3), and γ-mangostin (4). Further studies on these compounds are recommended to validate the Nrf2 modulatory ability in relation to their gastroprotective action.
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Khamis N, Zheng Y, Diamantakis MN, Clarkson GJ, Liu J, Wills M. Regio- and Enantioselective Asymmetric Transfer Hydrogenation of One Carbonyl Group in a Diketone through Steric Hindrance. J Org Chem 2024; 89:2759-2763. [PMID: 38308650 PMCID: PMC10877611 DOI: 10.1021/acs.joc.3c01950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 01/12/2024] [Accepted: 01/23/2024] [Indexed: 02/05/2024]
Abstract
On the basis of steric hindrance, one carbonyl group in a diketone can be reduced in a regioselective manner, with high enantioselectivity. The methodology can be extended to ketones with varied length of hydrocarbon chain spacing, and the products can be converted by oxidation to hydroxy esters or lactones without loss of enantiopurity.
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Tan WN, Samling BA, Tong WY, Chear NJY, Yusof SR, Lim JW, Tchamgoue J, Leong CR, Ramanathan S. Chitosan-Based Nanoencapsulated Essential Oils: Potential Leads against Breast Cancer Cells in Preclinical Studies. Polymers (Basel) 2024; 16:478. [PMID: 38399856 PMCID: PMC10891598 DOI: 10.3390/polym16040478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 01/31/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
Since ancient times, essential oils (EOs) derived from aromatic plants have played a significant role in promoting human health. EOs are widely used in biomedical applications due to their medicinal properties. EOs and their constituents have been extensively studied for treating various health-related disorders, including cancer. Nonetheless, their biomedical applications are limited due to several drawbacks. Recent advances in nanotechnology offer the potential for utilising EO-loaded nanoparticles in the treatment of various diseases. In this aspect, chitosan (CS) appears as an exceptional encapsulating agent owing to its beneficial attributes. This review highlights the use of bioactive EOs and their constituents against breast cancer cells. Challenges associated with the use of EOs in biomedical applications are addressed. Essential information on the benefits of CS as an encapsulant, the advantages of nanoencapsulated EOs, and the cytotoxic actions of CS-based nanoencapsulated EOs against breast cancer cells is emphasised. Overall, the nanodelivery of bioactive EOs employing polymeric CS represents a promising avenue against breast cancer cells in preclinical studies.
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Liu L, Bashir S, Ling GZ, Hoe LK, Liew J, Kasi R, Subramaniam RT. Enhanced Sodium Ion Batteries' Performance: Optimal Strategies on Electrolytes for Different Carbon-based Anodes. CHEMSUSCHEM 2024; 17:e202300876. [PMID: 37695539 DOI: 10.1002/cssc.202300876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 09/09/2023] [Accepted: 09/11/2023] [Indexed: 09/12/2023]
Abstract
Carbon-based materials have emerged as promising anodes for sodium-ion batteries (SIBs) due to the merits of cost-effectiveness and renewability. However, the unsatisfactory performance has hindered the commercialization of SIBs. During the past decades, tremendous attention has been put into enhancing the electrochemical performance of carbon-based anodes from the perspective of improving the compatibility of electrolytes and electrodes. Hence, a systematic summary of strategies for optimizing electrolytes between hard carbon, graphite, and other structural carbon anodes of SIBs is provided. The formulations and properties of electrolytes with solvents, salts, and additives added are comprehensively presented, which are closely related to the formation of solid electrolyte interface (SEI) and crucial to the sodium ion storage performance. Cost analysis of commonly used electrolytes has been provided as well. This review is anticipated to provide guidance in future rational tailoring of electrolytes with carbon-based anodes for sodium-ion batteries.
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Liang G, Kow ASF, Yusof R, Tham CL, Ho YC, Lee MT. Menopause-Associated Depression: Impact of Oxidative Stress and Neuroinflammation on the Central Nervous System-A Review. Biomedicines 2024; 12:184. [PMID: 38255289 PMCID: PMC10813042 DOI: 10.3390/biomedicines12010184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 12/21/2023] [Accepted: 01/09/2024] [Indexed: 01/24/2024] Open
Abstract
Perimenopausal depression, occurring shortly before or after menopause, is characterized by symptoms such as emotional depression, anxiety, and stress, often accompanied by endocrine dysfunction, particularly hypogonadism and senescence. Current treatments for perimenopausal depression primarily provide symptomatic relief but often come with undesirable side effects. The development of agents targeting the specific pathologies of perimenopausal depression has been relatively slow. The erratic fluctuations in estrogen and progesterone levels during the perimenopausal stage expose women to the risk of developing perimenopausal-associated depression. These hormonal changes trigger the production of proinflammatory mediators and induce oxidative stress, leading to progressive neuronal damage. This review serves as a comprehensive overview of the underlying mechanisms contributing to perimenopausal depression. It aims to shed light on the complex relationship between perimenopausal hormones, neurotransmitters, brain-derived neurotrophic factors, chronic inflammation, oxidative stress, and perimenopausal depression. By summarizing the intricate interplay between hormonal fluctuations, neurotransmitter activity, brain-derived neurotrophic factors, chronic inflammation, oxidative stress, and perimenopausal depression, this review aims to stimulate further research in this field. The hope is that an increased understanding of these mechanisms will pave the way for the development of more effective therapeutic targets, ultimately reducing the risk of depression during the menopausal stage for the betterment of psychological wellbeing.
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Sale S, Subramaniam S, Mad’ Atari MF. Trends in the Tissue Culture Techniques and the Synthesis of Bioactive Compounds in Eurycoma longifolia Jack-Current Status and Future Perspectives. PLANTS (BASEL, SWITZERLAND) 2023; 13:107. [PMID: 38202415 PMCID: PMC10780575 DOI: 10.3390/plants13010107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024]
Abstract
Over the last two decades, there has been a concerted effort by researchers to mass propagate Eurycoma longifolia and improve the yield of its very important and sought-after anti-cancer and aphrodisiac bioactive compounds. To achieve this, various techniques have been used to mass propagate and improve the yield of these bioactive compounds in tissue cultures. These techniques include the optimization of media conditions and application of various types and combinations of plant growth regulators (PGRs). In addition, some elicitation techniques have been used to improve the synthesis of these bioactive compounds. However, in comparison with other herbal species with similar economic importance, many techniques have not been applied to E. longifolia. Adopting the most recent methodologies would ensure efficiency and sustainability in the in vitro production of bioactive compounds in E. longifolia. Therefore, in this review, we present an up-to-date record on the success stories in the tissue culture techniques and synthesis of bioactive compounds. In addition, we attempted to identify some of the missing links on the road to the effective and sustainable biotechnological utilization of this super important biological resource.
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Reza T, Mohamad Riza ZH, Sheikh Abdullah SR, Abu Hasan H, Ismail N‘I, Othman AR. Microplastic Removal in Wastewater Treatment Plants (WWTPs) by Natural Coagulation: A Literature Review. TOXICS 2023; 12:12. [PMID: 38250968 PMCID: PMC10819662 DOI: 10.3390/toxics12010012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/06/2023] [Accepted: 12/13/2023] [Indexed: 01/23/2024]
Abstract
Urban industrialization has caused a ubiquity of microplastics in the environment. A large percentage of plastic waste originated from Southeast Asian countries. Microplastics arising from the primary sources of personal care items and industrial uses and the fragmentation of larger plastics have recently garnered attention due to their ubiquity. Due to the rising level of plastic waste in the environment, the bioaccumulation and biomagnification of plastics threaten aquatic and human life. Wastewater treatment plant (WWTP) effluents are one of the major sources of these plastic fragments. WWTPs in Southeast Asia contribute largely to microplastic pollution in the marine environment, and thus, further technological improvements are required to ensure the complete and efficient removal of microplastics. Coagulation is a significant process in removing microplastics, and natural coagulants are far superior to their chemical equivalents due to their non-toxicity and cost-effectiveness. A focused literature search was conducted on journal repository platforms, mainly ScienceDirect and Elsevier, and on scientific databases such as Google Scholar using the keywords Wastewater Treatment Plant, Coagulation, Microplastics, Marine Environment and Southeast Asia. The contents and results of numerous papers and research articles were reviewed, and the relevant papers were selected. The relevant findings and research data are summarized in this paper. The paper reviews (1) natural coagulants for microplastic removal and their effectiveness in removing microplastics and (2) the potential use of natural coagulants in Southeast Asian wastewater treatment plants as the abundance of natural materials readily available in the region makes it a feasible option for microplastic removal.
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Abdelhady R, Senthong P, Eyers CE, Reamtong O, Cowley E, Cannizzaro L, Stimpson J, Cain K, Wilkinson OJ, Williams NH, Barran PE, Margison GP, Williams DM, Povey AC. Mass Spectrometric Analysis of the Active Site Tryptic Peptide of Recombinant O6-Methylguanine-DNA Methyltransferase Following Incubation with Human Colorectal DNA Reveals the Presence of an O6-Alkylguanine Adductome. Chem Res Toxicol 2023; 36:1921-1929. [PMID: 37983188 PMCID: PMC10731659 DOI: 10.1021/acs.chemrestox.3c00207] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/31/2023] [Accepted: 11/01/2023] [Indexed: 11/22/2023]
Abstract
Human exposure to DNA alkylating agents is poorly characterized, partly because only a limited range of specific alkyl DNA adducts have been quantified. The human DNA repair protein, O6-methylguanine O6-methyltransferase (MGMT), irreversibly transfers the alkyl group from DNA O6-alkylguanines (O6-alkGs) to an acceptor cysteine, allowing the simultaneous detection of multiple O6-alkG modifications in DNA by mass spectrometric analysis of the MGMT active site peptide (ASP). Recombinant MGMT was incubated with oligodeoxyribonucleotides (ODNs) containing different O6-alkGs, Temozolomide-methylated calf thymus DNA (Me-CT-DNA), or human colorectal DNA of known O6-MethylG (O6-MeG) levels. It was digested with trypsin, and ASPs were detected and quantified by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. ASPs containing S-methyl, S-ethyl, S-propyl, S-hydroxyethyl, S-carboxymethyl, S-benzyl, and S-pyridyloxobutyl cysteine groups were detected by incubating MGMT with ODNs containing the corresponding O6-alkGs. The LOQ of ASPs containing S-methylcysteine detected after MGMT incubation with Me-CT-DNA was <0.05 pmol O6-MeG per mg CT-DNA. Incubation of MGMT with human colorectal DNA produced ASPs containing S-methylcysteine at levels that correlated with those of O6-MeG determined previously by HPLC-radioimmunoassay (r2 = 0.74; p = 0.014). O6-CMG, a putative O6-hydroxyethylG adduct, and other potential unidentified MGMT substrates were also detected in human DNA samples. This novel approach to the identification and quantitation of O6-alkGs in human DNA has revealed the existence of a human DNA alkyl adductome that remains to be fully characterized. The methodology establishes a platform for characterizing the human DNA O6-alkG adductome and, given the mutagenic potential of O6-alkGs, can provide mechanistic information about cancer pathogenesis.
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Tai MH, Thiam HS, Tee SF, Lim YS, Saw LH, Lai SO. Self-Healing Sulfonated Poly(ether ether ketone)-Based Polymer Electrolyte Membrane for Direct Methanol Fuel Cells: Effect of Solvent Content. Polymers (Basel) 2023; 15:4641. [PMID: 38139893 PMCID: PMC10747481 DOI: 10.3390/polym15244641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 11/27/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023] Open
Abstract
Proton exchange membranes (PEMs) with superior characteristics are needed to advance fuel cell technology. Nafion, the most used PEM in direct methanol fuel cells (DMFCs), has excellent proton conductivity but suffers from high methanol permeability and long-term performance degradation. Thus, this study aimed to create a healable PEM with improved durability and methanol barrier properties by combining sulfonated poly(ether ether ketone) (SPEEK) and poly-vinyl alcohol (PVA). The effect of changing the N,N-dimethylacetamide (DMAc) solvent concentration during membrane casting was investigated. Lower DMAc concentrations improved water absorption and, thus, membrane proton conductivity, but methanol permeability increased correspondingly. For the best trade-off between these two characteristics, the blend membrane with a 10 wt% DMAc solvent (SP10) exhibited the highest selectivity. SP10 also showed a remarkable self-healing capacity by regaining 88% of its pre-damage methanol-blocking efficiency. The ability to self-heal decreased with the increasing solvent concentration because of the increased crosslinking density and structure compactness, which reduced chain mobility. Optimizing the solvent concentration during membrane preparation is therefore an important factor in improving membrane performance in DMFCs. With its exceptional methanol barrier and self-healing characteristics, the pioneering SPEEK/PVA blend membrane may contribute to efficient and durable fuel cell systems.
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