Functionalization of poly (lactic-co-glycolic acid) nano‑calcium sulphate and fucoidan 3D scaffold using human bone marrow mesenchymal stromal cells for bone tissue engineering application

This study aimed to functionalize a novel porous PLGA (Poly lactic-co-glycolic acid) composite scaffold in combination with nano‑calcium sulphate (nCS) and/or fucoidan (FU) to induce osteogenic differentiation of human bone marrow stromal cells. The composite scaffolds (PLGA-nCS-FU, PLGA-nCS or PLGA-FU) were fabricated and subjected to characterization using Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Scanning electron microscopy (SEM) and Energy Dispersive X-Ray (EDX). The biocompatibility and osteogenic induction potential of scaffolds on seeded human bone marrow derived mesenchymal stromal cells (hBMSCs) were studied using cell attachment and alamar blue cell viability and alkaline phosphatase (ALP), osteocalcin and osteogenic gene expression, respectively. The composition of different groups was reflected in FTIR, XRD and EDX. The SEM micrographs revealed a difference in the surface of the scaffold before and after FU addition. The confocal imaging and SEM micrographs confirmed the attachment of cells onto all three composite scaffolds. However, the AB assay indicated a significant increase (p < 0.05) in cell viability/proliferation seeded on PLGA-nCS-FU on day 21 and 28 as compared with other combinations. A 2-fold significant increase (p < 0.05) in ALP and OC secretion of seeded hBMSCs onto PLGA-nCS-FU was observed when compared with other combinations. A significant increase in RUNX2, OPN, COL-I and ALP genes were observed in the cells seeded on PLGA-nCS-FU on day 14 and 28 as compared with day 0. In conclusion, the incorporation of both Fucoidan and Nano‑calcium sulphate with PLGA showed a promising improvement in the osteogenic potential of hBMSCs. Therefore, PLGA-nCS-FU could be the ideal candidate for subsequent pre-clinical studies to develop a successful bone substitute to repair critical bone defects.

Descemet stripping endothelial keratoplasty versus penetrating keratoplasty in bullous keratopathy: A 2-year analysis of graft survival and outcomes in a tertiary eye centre in Kuala Lumpur

INTRODUCTION

This study aims to compare the 2-year graft survival and outcomes of descemet stripping endothelial keratoplasty (DSEK) and penetrating keratoplasty (PK) for the treatment of bullous keratopathy (BK) among multiethnic Malaysia populations treated at a Tertiary Eye Centre in Kuala Lumpur, Malaysia.

MATERIALS AND METHODS

This was a retrospective study of BK or Fuchs endothelial dystrophy (FED) patients who underwent DSEK or PK from 2015 to 2019 in Kuala Lumpur Hospital with a minimal post-operative follow-up of 2 years. Outcome measures included best-corrected visual acuity (BCVA), graft survival and complications. A total of 26 DSEK cases and 32 PK cases were included.

RESULTS

At 2 years, graft survival rates were quite similar in two groups (DSEK 80.8% vs PK 75%, p=0.765). The mean follow-up period was 35.2 months in DSEK and 31.4 months for PK (p=0.465). The cumulative survival rates were slightly higher in the DSEK group (DSEK 73.1% vs PK 53.1%, p=0.119), but the result was not statistically significant. Postoperative complications were associated with higher graft failure in both groups (p=0.019). DSEK group has better post-operative BCVA (LogMAR DSEK 0.42 vs PK 0.83, p=0.003).

CONCLUSION

Similar graft survival rates were observed with both corneal transplant techniques for 2 years among Malaysian patients with BK. Post-operative complications can cause a higher risk of graft failure. DSEK produced better post-operative BCVA compared to PK.

Synergistic of antimicrobial activities of lactic acid bacteria in fermented Tilapia nicoliticus incorporated with selected spices

Fermented tilapia (Tilapia nicoliticus) is one of the famous fermented food in Malaysia. Lactic acid bacteria (LAB) which well known as GRAS (Generally Regarded as Safe) are present in most fermented foods and they are well-known non-pathogenic bacteria that play an important role in everyday life. Apart from LAB, spices have also been used for centuries across different regions of the world to improve aroma, flavour and food preservative. This research was aimed to explore a potential natural food preservative using LAB isolated from fermented Tilapia nicoliticus incorporated with various spices (9% turmeric, 6% chilli and 9% black pepper) against foodborne pathogens. The isolation of LAB in different media (MRS, MRS+CaCO3, M17 and Tomato Juice Agar) showed the highest LAB count on day-9 and day-15 during the fermentation period in fermented Tilapia incorporated with black pepper, turmeric and chilli. The highest antimicrobial activity by LAB against Bacillus cereus was observed in fermented tilapia incorporated with black pepper. On the other hand, fermented fish incorporated with chilli showed the highest antimicrobial activity against Staphylococcus aureus, Escherichia coli and Salmonella enterica serovar Typhimurium. Higher antimicrobial activity was detected in fermented Tilapia in the presence of LAB together with the spices, in comparison to the presence of LAB alone, suggesting synergistic effects between LAB in fermented fish with spices could enhance stronger antimicrobial activities against food pathogens and therefore, served as a natural food preservative.

Survival of antibiotic resistant Escherichia coli in vacuumpacked keropok lekor: Food safety alert among SME keropok lekor producers

The microbiological quality of thirty ready-to-eat (RTE) keropok lekor (a sausage shape Malaysian fish product) was evaluated in comparison to microbiological guidelines for ready to eat foods. The two E. coli isolates were subjected to DNA sequencing, identified and tested for their resistance towards fifteen different antibiotics. The survival and growth of the isolated E. coli strains inoculated in keropok lekor at atmospheric air and vacuum packaging were also evaluated. Results revealed that four samples (13.33%) contained Enterobacteriaceae counts that exceeded the recommended allowable counts of 4.0 log₁₀ CFU/g. Unsatisfactory level of coliforms (< 1.7 log₁₀ CFU/g) was also observed in ten of the samples; two of which contained E. coli (2.1 ± 0.17 and 3.7 ± 0.02 log₁₀ CFU/g), suggesting of poor hygiene and sanitation practices. While the 'Possible E10' E. coli strain was observably resistant towards Nalidixic acid (30µg) alone, B10 E. coli isolate was worryingly resistant towards Ampicillin (10µg), Ceftazidime (30µg), Ciprofloxacin (5µg), Ceftriaxone (30µg), Nalidixic acid (30µg) and Tetracycline (30µg). This study also revealed that the growth and survival of the 'Possible E10' and B10 E. coli strains were not significantly affected by vacuum packaging when stored at both 4°C and 28°C. Therefore, intervention programmes to alert and educate smallmedium enterprisers (SMEs) of keropok lekor producers on food safety as well as potential health risks that can be associated due to inappropriate handling procedures of such product, merits consideration.

The application of taḥawwul (transformation) process for determination of vinegar status in the Malaysia market

Taḥawwul is a changing process of a form to another form thus could affect the status of a particular ḥukm especially in vinegar products. Vinegar which produced before the taḥawwul ṣaḥīḥ can be considered as low-quality vinegar and is classified as fasīd vinegar (ḥarām) due to the presences of alcohol which is prohibited in Islam. Therefore, in this study, twenty-five different types of vinegar in Malaysian market were tested using Gas Chromatography attached with Flame Ionization Detector (HS-GC-FID) with Head Space Analyzer (HS-10) and Gas Chromatography (GC) with time of flight mass spectrometry (TOF-MS) to find out the contents of alcohol and acetic acids present in the said vinegar products. The results showed that majority of the sample were ḥalāl. However, there were two types of vinegar that were not considered ḥalāl because these products did not go through a complete process of (taḥawwul ṣaḥīḥ).

In vitro evaluation of novel low-pressure spark plasma sintered HA–BG composite scaffolds for bone tissue engineering

The low-pressure spark plasma sintering (SPS) technique is adopted to fabricate hydroxyapatite–bioglass (HA–BG) scaffolds while maintaining the physical properties of both components, including their bulk and relative density and hardness. However, prior to their orthopaedic and dental applications, these scaffolds must be validated via pre-clinical assessments. In the present study, scaffolds with different ratios of HA : BG, namely, 100 : 0 (HB 0 S), 90 : 10 (HB 10 S), 80 : 20 (HB 20 S) and 70 : 30 (HB 30 S) were fabricated. These scaffolds were characterized by investigating their physicochemical properties (X-ray diffraction (XRD) and surface wettability), bioactivity in a simulated body fluid (SBF) (field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR) and calcium dissolution), antimicrobial properties, biocompatibility and osteoinduction of human bone marrow-derived mesenchymal stromal cells (hBMSCs) and human monocyte immune cell response. The XRD and surface wettability results confirmed no formation of undesirable phases and the enhanced surface hydrophilicity of the scaffolds, respectively. The bioactivity in SBF indicated the formation of bone-like apatite on the surface of the scaffolds, corresponding to an increase in BG%, which was confirmed through FTIR spectra and the increasing trend of calcium release in SBF. The scaffolds showed inhibition properties against Staphylococcus aureus and Staphylococcus epidermidis. The scanning electron microscopy (SEM) micrographs and Alamar Blue proliferation assay indicated the good attachment and significant proliferation, respectively, of hBMSCs on the scaffolds. Alizarin Red S staining confirmed that the scaffolds supported the mineralisation of hBMSCs. The osteogenic protein secretion (bone morphogenetic protein-2 (BMP2), type-I collagen (COL1) and osterix (OSX)) was significant on the HB 30 S-seeded hBMSCs when compared with that of HB 0 S. The monocyte migration was significantly halted in response to HA–BG-conditioned media when compared with the positive control (monocyte chemoattractant protein-1: MCP-1). In conclusion, the HB 30 S composite scaffold has a greater potential to substitute bone grafts in orthopaedic and dental applications.

HB 30 S composite scaffold inhibits Staphylococcus spp., supports the biocompatibility and osteogenic differentiation of hBMSCs and resists monocyte migration.

Mechanical, antibacterial, and biocompatibility mechanism of PVD grown silver-tantalum-oxide-based nanostructured thin film on stainless steel 316L for surgical applications

Surgical site infection associated with surgical instruments has always been a factor in delaying post-operative recovery of patients. The evolution in surface modification of surgical instruments can be a potential choice to overcome the nosocomial infection mainly caused by bacterial populations such as Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. A study was, therefore, conducted characterising the morphology, hydrophobicity, adhesion strength, phase, Nano-hardness, surface chemistry, antimicrobial and biocompatibility of SS 316L steel deposited with a Nano-composite layer of Silver (Ag) and Tantalum oxide (Ta₂O₅) using physical vapour deposition magnetron sputtering. The adhesion strength of Ag/AgTa₂O₅ coating on SS 316L and treated at 250-850 °C of thermal treatment was evaluated using micro-scratch. The Ag/Ag-Ta₂O₅-400 °C was shown a 154% improvement in adhesion strength on SS 316L when compared with as-sputtered layer or Ag/Ag-Ta₂O₅-250, 550, 700 and 850 °C. The FESEM, XPS, and XRD indicated the segregation of Ag on the surface of SS 316L after the crystallization. Wettability and Nano-indentation tests demonstrated an increase in hydrophobicity (77.3 ± 0.3°) and Nano-hardness (1.12 ± 0.43 GPa) when compared with as-sputtered layer, after the 400 °C of thermal treatment. The antibacterial performance on Ag/Ag-Ta₂O₅-400 °C indicated a significant zone of inhibition to Staphylococcus aureus (A-axis: 16.33 ± 0.58 mm; B-axis: 25.67 ± 0.58 mm, p < 0.01) and Escherichia coli (A-axis: 16.33 ± 1.15 mm; B-axis: 26.00 ± 0.00 mm, p < 0.01) when compared with SS 316L or Ag/Ag-Ta₂O₅-700 °C, which showed no inhibition. The biocompatibility tests on Ag/Ag-Ta₂O₅-400 °C demonstrated an excellent in cell attachment, F-actin protein expression and proliferation/viability of bone marrow derived mesenchymal stromal on day 14 when compared with uncoated or Ag/Ag-Ta₂O₅-700 °C. This study shows that the Ag segregation process, hydrophobicity, adhesion strength, crystallization, and hardness progressively improved after the annealing up to 400 °C.

Cultivated oral mucosal epithelial transplantation (COMET) and penetrating keratoplasty in long-standing severe ocular surface injury

Ocular chemical injury is a true ophthalmic emergency requiring immediate medical intervention. Damages can be devastating and potentially resulting in blindness, corneal perforation and phthisis bulbi. We describe here a successful treatment outcome in a patient who sustained Roper-Hall Grade 4 injury to both eyes. Patient received medical therapy followed by serial ocular surgeries with eventual visual recovery in one eye from counting finger to 6/15 after a decade. In conclusion, after maximum medical therapy, a carefully planned serial surgeries of cultivated oral mucosal epithelial transplantation (COMET) and PK has proven beneficial for this patient with advanced limbal stem cell deficiency (LSCD).

Human milk as a potential source for isolation of probiotic lactic acid bacteria: a mini review

Probiotics are living microorganism that can be employed as a new approach to promote human health. These organisms are found to have attractive means for health due to their probiotic properties particularly in generating antimicrobial activity. Lactobacillus spp. is one of the main genera commonly used for probiotic purpose. Human milk is a potential source of Lactobacillus spp. and one of the criteria that found beneficial is that it is of human origin, which could be more reliable sources to be used in human. Lack of studies on isolation of probiotic bacteria from human milk was reported and some probiotic properties show a variation between strains from different regions and population. Therefore, it is important to carry out the isolation of Lactobacillus spp. from a large number of species in the genera to facilitate the finding of the most competent strain to be incorporated as probiotic agent. Moreover, to ensure suitability and compatibility for human use, the probiotic agent originated from human milk should not be an exception. In addition, certain probiotics show a great correlation with prebiotic existed in human milk to boost their function and may suggest an added value to be a suitable candidate as probiotic. This review provides an overview of studies related to human milk as the promising sources for isolation of probiotic microorganisms.

Surface modification of valve metals using plasma electrolytic oxidation for antibacterial applications: A review

Plasma electrolytic oxidation (PEO) is an advance technique to develop porous oxidation layer on light metals, primarily to enhance corrosion and wear resistance. The oxidation layer can also offer a wide variety of mechanical, biomedical, tribological, and antibacterial properties through the incorporation of several ions and particles. Due to the increasing need of antimicrobial surfaces for biomedical implants, antibacterial PEO coatings have been developed through the incorporation of antibacterial agents. Metallic nanoparticles that have been employed most widely as antibacterial agents are reported to demonstrate serious health and environmental threats. To overcome the current limitations of these coatings, there is a significant need to develop antibacterial surfaces that are not harmful for patient's health and environment. Attention of the readers has been directed to utilize bioactive glasses as antibacterial agents for PEO coatings. Bioactive glasses are well known for their excellent bioactivity, biocompatibility, and antibacterial character. PEO coatings incorporated with bioactive glasses can provide environment-friendly antimicrobial surfaces with exceptional bioactivity, biocompatibility, and osseointegration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 590-605, 2018.

Mupirocin resistance among Malaysian isolates of methicillin-resistant Staphylococcus aureus

Four hundred methicillin-resistant Staphylococcus aureus strains (MRSA) from different geographical areas in Malaysia were tested for mupirocin susceptibility using minimum inhibitory concentration (MIC) determination. The majority of these strains (98.75%) were susceptible to mupirocin with MICs of < or = 4 mg/l. Fifty-percent of these strains had MICs of 0.125 mg/l or less while 90% of the strains had MICs of 1 mg/l or less. Mupirocin resistance was detected in five strains (1.25%) and one of these (0.25%) had an MIC of 64 mg/l and the other four strains (1%), high-level resistance with MICs > 512 mg/l. Even though the rate of mupirocin resistance in MRSA is still low in Malaysia, its presence calls for a strict policy on mupirocin usage in Malaysian hospitals.