Displaying publications 1 - 20 of 53 in total

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  1. Kumaran SK, Bakar MFA, Mohd-Padil H, Mat-Sharani S, Sakinah S, Poorani K, et al.
    Acta Trop, 2017 Dec;176:433-439.
    PMID: 28941729 DOI: 10.1016/j.actatropica.2017.09.011
    Leptospirosis is a widespread zoonotic disease caused by pathogenic Leptospira species (Leptospiraceae). LipL32 is an abundant lipoprotein from the outer membrane proteins (OMPs) group, highly conserved among pathogenic and intermediate Leptospira species. Several studies used LipL32 as a specific gene to identify the presence of leptospires. This research was aimed to study the characteristics of LipL32 protein gene code, to fill the knowledge gap concerning the most appropriate gene that can be used as antigen to detect the Leptospira. Here, we investigated the features of LipL32 in fourteen Leptospira pathogenic strains based on comparative analyses of their primary, secondary structures and 3D modeling using a bioinformatics approach. Furthermore, the physicochemical properties of LipL32 in different strains were studied, shedding light on the identity of signal peptides, as well as on the secondary and tertiary structure of the LipL32 protein, supported by 3D modelling assays. The results showed that the LipL32 gene was present in all the fourteen pathogenic Leptospira strains used in this study, with limited diversity in terms of sequence conservation, hydrophobic group, hydrophilic group and number of turns (random coil). Overall, these results add basic knowledge to the characteristics of LipL32 protein, contributing to the identification of potential antigen candidates in future research, in order to ensure prompt and reliable detection of pathogenic Leptospira species.
  2. Higuchi A, Wang CT, Ling QD, Lee HH, Kumar SS, Chang Y, et al.
    Sci Rep, 2015;5:10217.
    PMID: 25970301 DOI: 10.1038/srep10217
    Human adipose-derived stem cells (hADSCs) exhibit heterogeneous characteristics, indicating various genotypes and differentiation abilities. The isolated hADSCs can possess different purity levels and divergent properties depending on the purification methods used. We developed a hybrid-membrane migration method that purifies hADSCs from a fat tissue solution with extremely high purity and pluripotency. A primary fat-tissue solution was permeated through the porous membranes with a pore size from 8 to 25 μm, and the membranes were incubated in cell culture medium for 15-18 days. The hADSCs that migrated from the membranes contained an extremely high percentage (e.g., >98%) of cells positive for mesenchymal stem cell markers and showed almost one order of magnitude higher expression of some pluripotency genes (Oct4, Sox2, Klf4 and Nanog) compared with cells isolated using the conventional culture method.
  3. Arulselvan P, Tan WS, Gothai S, Muniandy K, Fakurazi S, Esa NM, et al.
    Molecules, 2016 Oct 31;21(11).
    PMID: 27809259
    In the present investigation, we prepared four different solvent fractions (chloroform, hexane, butanol, and ethyl acetate) of Moringa oleifera extract to evaluate its anti-inflammatory potential and cellular mechanism of action in lipopolysaccharide (LPS)-induced RAW264.7 cells. Cell cytotoxicity assay suggested that the solvent fractions were not cytotoxic to macrophages at concentrations up to 200 µg/mL. The ethyl acetate fraction suppressed LPS-induced production of nitric oxide and proinflammatory cytokines in macrophages in a concentration-dependent manner and was more effective than the other fractions. Immunoblot observations revealed that the ethyl acetate fraction effectively inhibited the expression of inflammatory mediators including cyclooxygenase-2, inducible nitric oxide synthase, and nuclear factor (NF)-κB p65 through suppression of the NF-κB signaling pathway. Furthermore, it upregulated the expression of the inhibitor of κB (IκBα) and blocked the nuclear translocation of NF-κB. These findings indicated that the ethyl acetate fraction of M. oleifera exhibited potent anti-inflammatory activity in LPS-stimulated macrophages via suppression of the NF-κB signaling pathway.
  4. Sundaram CS, Kumar JS, Kumar SS, Ramesh PLN, Zin T, Rao USM
    Med J Malaysia, 2020 11;75(6):677-684.
    PMID: 33219177
    INTRODUCTION: Brassica oleracea var acephala was studied for preliminary phytochemical screening. The results showed that the ethanolic crude extract of the leaf contain high phytochemical activity hence B.oleracea var acephala is rich in flavonoids, phenolic compounds, carbohydrates and phytosterols.

    MATERIALS AND METHODS: The ethanolic extract was used to synthesise copper nanoparticles. The copper nanoparticles were successfully synthesised from copper sulphate solution which was identified by the colour change from dark green colour of the extract. Thus the B.oleracea var acephala is a good source to synthesis copper nanoparticles. The synthesised copper nanoparticles were characterised using Scanning Electron Microscope (SEM) analysis. The SEM image displayed the high-density nanoparticles synthesised by leaf extracts and that the nanoparticles were crystals in shape.

    RESULTS: The copper nanoparticles (CNP) bind to the leaf extract. B.oleracea var acephala also has shown the antimicrobial and antioxidant activity. A comparative study was done between ethanolic its crude extract and nanoparticles. Both extracts exhibited zone of inhibition and better antioxidant potential but the CuNPs shows major zone of inhibition and showed more antioxidant activity. Anticancer activity of B.oleracea var acephala against Cervical HeLa cell line was confirmed using ethanolic crude extract and CNP. The results showed that HeLa cells proliferation was inhibited with increasing concentration of ethanolic crude extract and copper nanoparticles. From the results, it was seen that percentage viability of the cancer cells decreased with increased concentration of the samples whereas cytotoxicity against HeLa cell lines increased with the increased concentration of the samples.

    CONCLUSION: Thus B.oleracea var acephala possesses anticancer activity against HeLa cell lines.

  5. Cui YC, Wu Q, Teh SW, Peli A, Bu G, Qiu YS, et al.
    Microb Pathog, 2018 Sep;122:130-136.
    PMID: 29909241 DOI: 10.1016/j.micpath.2018.06.021
    The recent global resurgence of arthritogenic alphaviruses, including Ross River, chikungunya, and dengue, highlights an urgency for the development of therapeutic strategies. Currently, dengue represents the most rapidly transmitting mosquito-borne viral disease worldwide. By contracting bone breaking diseases, patients experience devastating clinical manifestations involving muscle pain and bone loss. The bone self-repair and regeneration mechanisms can be damaged by the presence of viruses and bacteria. The rapid establishment of dengue epidemic and the severity of bacterial and viral infections affecting the bone stress the urgent need of developing effective interventions. Herein, we review current knowledge on bone breaking infections, covering both bacterial and mosquito-borne viral ones. The mechanisms exploited by these diseases to significantly affect the bone, including interferences with self-repair and regeneration routes, were discussed. In the final section, challenges for future research aimed to treat and prevent bacterial and mosquito-borne bone-breaking infections have been outlined.
  6. Gothai S, Muniandy K, Zarin MA, Sean TW, Kumar SS, Munusamy MA, et al.
    Pharmacogn Mag, 2017 Oct;13(Suppl 3):S462-S469.
    PMID: 29142400 DOI: 10.4103/pm.pm_368_16
    Background: Moringa oleifera (MO), commonly known as the drumstick tree, is used in folklore medicine for the treatment of skin disease.

    Objective: The objective of this study is to evaluate the ethyl acetate (EtOAc) fraction of MO leaves for in vitro antibacterial, antioxidant, and wound healing activities and conduct gas chromatography-mass spectrometry (GC-MS) analysis.

    Materials and Methods: Antibacterial activity was evaluated against six Gram-positive bacteria and 10 Gram-negative bacteria by disc diffusion method. Free radical scavenging activity was assessed by 1, 1-diphenyl-2-picryl hydrazyl (DPPH) radical hydrogen peroxide scavenging and total phenolic content (TPC). Wound healing efficiency was studied using cell viability, proliferation, and scratch assays in diabetic human dermal fibroblast (HDF-D) cells.

    Results: The EtOAc fraction showed moderate activity against all bacterial strains tested, and the maximum inhibition zone was observed against Streptococcus pyogenes (30 mm in diameter). The fraction showed higher sensitivity to Gram-positive strains than Gram-negative strains. In the quantitative analysis of antioxidant content, the EtOAc fraction was found to have a TPC of 65.81 ± 0.01. The DPPH scavenging activity and the hydrogen peroxide assay were correlated with the TPC value, with IC50 values of 18.21 ± 0.06 and 59.22 ± 0.04, respectively. The wound healing experiment revealed a significant enhancement of cell proliferation and migration of HDF-D cells. GC-MS analysis confirmed the presence of 17 bioactive constituents that may be the principal factors in the significant antibacterial, antioxidant, and wound healing activity.

    Conclusion: The EtOAc fraction of MO leaves possesses remarkable wound healing properties, which can be attributed to the antibacterial and antioxidant activities of the fraction.

    SUMMARY: Moringa oleifera (MO) leaf ethyl acetate (EtOAc) fraction possesses antibacterial activities toward Gram-positive bacteria such as Streptococcus pyogenes, Streptococcus faecalis, Bacillus subtilis, Bacillus cereus and Staphylococcus aureus, and Gram-negative bacteria such as Proteus mirabilis and Salmonella typhimuriumMO leaf EtOAc fraction contained the phenolic content of 65.81 ± 0.01 and flavonoid content of 37.1 ± 0.03, respectively. In addition, the fraction contained 17 bioactive constituents associated with the antibacterial, antioxidant, and wound healing properties that were identified using gas chromatography-mass spectrometry analysisMO leaf EtOAc fraction supports wound closure rate about 80% for treatments when compared with control group. Abbreviations used: MO: Moringa oleifera; EtOAc: Ethyl acetate; GC-MS: Gas Chromatography-Mass Spectrometry; HDF-D: Diabetic Human Dermal Fibroblast cells.

  7. Sumathra M, Sadasivuni KK, Kumar SS, Rajan M
    ACS Omega, 2018 Nov 30;3(11):14620-14633.
    PMID: 30555982 DOI: 10.1021/acsomega.8b02090
    Presently, tissue engineering approaches have been focused toward finding new potential scaffolds with osteoconductivity on bone-disease-affected cells. This work focused on the cisplatin (CDDP)-loaded graphene oxide (GO)/hydroxyapatite (HAP)/chitosan (CS) composite for enhancing the growth of osteoblast cells and prevent the development of osteosarcoma cells. The prepared composites were characterized for the confirmation of composite formation using Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction techniques. A flowerlike morphology was observed for the GO/HAP/CS-3/CDDP composite. UV-vis spectroscopy was used to observe the controlled release of CDDP from the GO/HAP/CS-3/CDDP composite, and 67.34% of CDDP was released from the composite over a time period of 10 days. The GO/HAP/CS-3/CDDP nanocomposites showed higher viability in comparison with GO/HAP/CS-3 on MG63 osteoblast-like cells and higher cytotoxicity against cancer cells (A549). The synthesized composite was found to show enhanced proliferative, adhesive, and osteoinductive effects on the alkaline phosphatase activity of osteoblast-like cells. Our results suggested that the CDDP-loaded GO/HAP/CS-3 nanocomposite has an immense prospective as a bone tissue replacement in the bone-cancer-affected tissues.
  8. Peng IC, Yeh CC, Lu YT, Muduli S, Ling QD, Alarfaj AA, et al.
    Biomaterials, 2016 Jan;76:76-86.
    PMID: 26519650 DOI: 10.1016/j.biomaterials.2015.10.039
    Stem cell culture is typically based on batch-type culture, which is laborious and expensive. Here, we propose a continuous harvest method for stem cells cultured on thermoresponsive nanobrush surfaces. In this method, stem cells are partially detached from the nanobrush surface by reducing the temperature of the culture medium below the critical solution temperature needed for thermoresponse. The detached stem cells are harvested by exchange into fresh culture medium. Following this, the remaining cells are continuously cultured by expansion in fresh culture medium at 37 °C. Thermoresponsive nanobrush surfaces were prepared by coating block copolymers containing polystyrene (for hydrophobic anchoring onto culture dishes) with three types of polymers: (a) polyacrylic acid with cell-binding oligopeptides, (b) thermoresponsive poly-N-isopropylacrylamide, and (c) hydrophilic poly(ethyleneglycol)methacrylate. The optimal coating durations and compositions for these copolymers to facilitate adequate attachment and detachment of human adipose-derived stem cells (hADSCs) and embryonic stem cells (hESCs) were determined. hADSCs and hESCs were continuously harvested for 5 and 3 cycles, respectively, via the partial detachment of cells from thermoresponsive nanobrush surfaces.
  9. Muniandy K, Gothai S, Tan WS, Kumar SS, Esa NM, Chandramohan G, et al.
    PMID: 32617103 DOI: 10.1155/2020/2705479
    [This corrects the article DOI: 10.1155/2018/3142073.].
  10. Sakinah S, Priya SP, Mok PL, Munisvaradass R, Teh SW, Sun Z, et al.
    Front Cell Dev Biol, 2021;9:800659.
    PMID: 35178398 DOI: 10.3389/fcell.2021.800659
    [This corrects the article DOI: 10.3389/fcell.2021.637270.].
  11. Yeh CC, Muduli S, Peng IC, Lu YT, Ling QD, Alarfaj AA, et al.
    Data Brief, 2016 Mar;6:603-8.
    PMID: 26909373 DOI: 10.1016/j.dib.2015.12.056
    This data article contains two figures and one table supporting the research article entitled: "Continuous harvest of stem cells via partial detachment from thermoresponsive nanobrush surface" [1]. The table shows coating conditions of three copolymers, poly(styrene-co-acrylic acid) grafted with oligovitronectin, poly(styrene-co-N-isopropylacrylamide) and poly(styrene-co-polyethylene glycol methacrylate) to prepare thermoresponsive surface. XPS spectra show the nitrogen peak of the polystyrene surface coated with poly(styrene-co-acrylic acid) grafted with oligovitronectin. The surface coating density analyzed from sorption of poly(styrene-co-acrylic acid) grafted with oligovitronectin by UV-vis spectroscopy is also presented.
  12. Alsaeedi HA, Koh AE, Lam C, Rashid MBA, Harun MHN, Saleh MFBM, et al.
    J. Photochem. Photobiol. B, Biol., 2019 Sep;198:111561.
    PMID: 31352000 DOI: 10.1016/j.jphotobiol.2019.111561
    Blindness and vision loss contribute to irreversible retinal degeneration, and cellular therapy for retinal cell replacement has the potential to treat individuals who have lost light sensitive photoreceptors in the retina. Retinal cells are well characterized in function, and are a subject of interest in cellular replacement therapy of photoreceptors and the retinal pigment epithelium. However, retinal cell transplantation is limited by various factors, including the choice of potential stem cell source that can show variability in plasticity as well as host tissue integration. Dental pulp is one such source that contains an abundance of stem cells. In this study we used dental pulp-derived mesenchymal stem cells (DPSCs) to mitigate sodium iodate (NaIO3) insult in a rat model of retinal degeneration. Sprague-Dawley rats were first given an intravitreal injection of 3 × 105 DPSCs as well as a single systemic administration of NaIO3 (40 mg/kg). Electroretinography (ERG) was performed for the next two months and was followed-up by histological analysis. The ERG recordings showed protection of DPSC-treated retinas within 4 weeks, which was statistically significant (* P ≤ .05) compared to the control. Retinal thickness of the control was also found to be thinner (*** P ≤ .001). The DPSCs were found integrated in the photoreceptor layer through immunohistochemical staining. Our findings showed that DPSCs have the potential to moderate retinal degeneration. In conclusion, DPSCs are a potential source of stem cells in the field of eye stem cell therapy due to its protective effects against retinal degeneration.
  13. Priya SP, Sunil PM, Varma S, Brigi C, Isnadi MFAR, Jayalal JA, et al.
    Virusdisease, 2022 Dec;33(4):429-444.
    PMID: 36311173 DOI: 10.1007/s13337-022-00793-9
    BACKGROUND: Severe acute respiratory syndrome Coronavirus-2 invades the cells via ACE2 receptor and damages multiple organs of the human body. Understanding the pathological manifestation is mandatory to endure the rising post-infection sequel reported in patients with or without comorbidities.

    MATERIALS AND METHODS: Our descriptive review emphasises the direct, indirect and post-infection damages due to COVID-19. We have performed an electronic database search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with selective inclusion and exclusion criteria.

    RESULTS: The included studies substantiated the extensive damages in the multiple organs due to direct and indirect consequences of COVID-19. After an apparent recovery, the prolonged presentation of the symptoms manifests as post-COVID that can be related with persisting viral antigens and dysregulated immune response.

    CONCLUSION: A few of the symptoms of respiratory, cardiovascular, and neuropsychiatric systems that persist or reappear as post-COVID manifestations. Vaccination and preventive programs will effectively reduce the prevalence but, the post-COVID, a multisystem manifestation, will be a significant tribulation to the medical profession. However, the issue can be managed by implementing public health programs, rehabilitation services, and telemedicine virtual supports to raise awareness and reduce panic.

  14. Sung TC, Li HF, Higuchi A, Kumar SS, Ling QD, Wu YW, et al.
    Biomaterials, 2020 02;230:119638.
    PMID: 31810728 DOI: 10.1016/j.biomaterials.2019.119638
    Human induced pluripotent stem cells (hiPSCs) were generated on several biomaterials from human amniotic fluid in completely xeno-free and feeder-free conditions via the transfection of pluripotent genes using a nonintegrating RNA Sendai virus vector. The effect of xeno-free culture medium on the efficiency of the establishment of human amniotic fluid stem cells from amniotic fluid was evaluated. Subsequently, the effect of cell culture biomaterials on the reprogramming efficiency was investigated during the reprogramming of human amniotic fluid stem cells into hiPSCs. Cells cultured in laminin-511, laminin-521, and Synthemax II-coated dishes and hydrogels having optimal elasticity that were engrafted with specific oligopeptides derived from vitronectin could be reprogrammed into hiPSCs with high efficiency. The reprogrammed cells expressed pluripotency proteins and had the capability to differentiate into cells derived from all three germ layers in vitro and in vivo. Human iPSCs could be generated successfully and at high efficiency (0.15-0.25%) in completely xeno-free conditions from the selection of optimal cell culture biomaterials.
  15. Krishnan P, Rajan M, Kumari S, Sakinah S, Priya SP, Amira F, et al.
    Sci Rep, 2017 09 08;7(1):10962.
    PMID: 28887536 DOI: 10.1038/s41598-017-09140-1
    Camptothecin (CPT) is an anti-cancer drug that effectively treats various cancers, including colon cancer. However, poor solubility and other drawbacks have restricted its chemotherapeutic potential. To overcome these restrictions, CPT was encapsulated in CEF (cyclodextrin-EDTA-FE3O4), a composite nanoparticle of magnetic iron oxide (Fe3O4), and β-cyclodextrin was cross-linked with ethylenediaminetetraacetic acid (EDTA). This formulation improved CPT's solubility and bioavailability for cancer cells. The use of magnetically responsive anti-cancer formulation is highly advantageous in cancer chemotherapy. The chemical characterisation of CPT-CEF was studied here. The ability of this nano-compound to induce apoptosis in HT29 colon cancer cells and A549 lung cancer cells was evaluated. The dose-dependent cytotoxicity of CPT-CEF was shown using MTT. Propidium iodide and Annexin V staining, mitochondrial membrane depolarisation (JC-1 dye), and caspase-3 activity were assayed to detect apoptosis in CPT-CEF-treated cancer cells. Cell cycle analysis also showed G1 phase arrest, which indicated possible synergistic effects of the nano-carrier. These study results show that CPT-CEF causes a dose-dependent cell viability reduction in HT29 and A549 cells and induces apoptosis in colon cancer cells via caspase-3 activation. These data strongly suggest that CPT could be used as a major nanocarrier for CPT to effectively treat colon cancer.
  16. Sung TC, Liu CH, Huang WL, Lee YC, Kumar SS, Chang Y, et al.
    Biomater Sci, 2019 Oct 28.
    PMID: 31656967 DOI: 10.1039/c9bm00817a
    Current xeno-free and chemically defined methods for the differentiation of hPSCs (human pluripotent stem cells) into cardiomyocytes are not efficient and are sometimes not reproducible. Therefore, it is necessary to develop reliable and efficient methods for the differentiation of hPSCs into cardiomyocytes for future use in cardiovascular research related to drug discovery, cardiotoxicity screening, and disease modeling. We evaluated two representative differentiation methods that were reported previously, and we further developed original, more efficient methods for the differentiation of hPSCs into cardiomyocytes under xeno-free, chemically defined conditions. The developed protocol successively differentiated hPSCs into cardiomyocytes, approximately 90-97% of which expressed the cardiac marker cTnT, with beating speeds and sarcomere lengths that were similar to those of a healthy adult human heart. The optimal cell culture biomaterials for the cardiac differentiation of hPSCs were also evaluated using extracellular matrix-mimetic material-coated dishes. Synthemax II-coated and Laminin-521-coated dishes were found to be the most effective and efficient biomaterials for the cardiac differentiation of hPSCs according to the observation of hPSC-derived cardiomyocytes with high survival ratios, high beating colony numbers, a similar beating frequency to that of a healthy adult human heart, high purity levels (high cTnT expression) and longer sarcomere lengths similar to those of a healthy adult human heart.
  17. Sung TC, Su HC, Ling QD, Kumar SS, Chang Y, Hsu ST, et al.
    Biomaterials, 2020 09;253:120060.
    PMID: 32450407 DOI: 10.1016/j.biomaterials.2020.120060
    The current differentiation process of human pluripotent stem cells (hPSCs) into cardiomyocytes to enhance the purity of hPSC-derived cardiomyocytes requires some purification processes, which are laborious processes. We developed cell sorting plates, which are prepared from coating thermoresponsive poly(N-isopropylacrylamide) and extracellular matrix proteins. After hPSCs were induced into cardiomyocytes on the thermoresponsive surface coated with laminin-521 for 15 days, the temperature of the cell culture plates was decreased to 8-9 °C to detach the cells partially from the thermoresponsive surface. The detached cells exhibited a higher cardiomyocyte marker of cTnT than the remaining cells on the thermoresponsive surface as well as the cardiomyocytes after purification using conventional cell selection. The detached cells expressed several cardiomyocyte markers, such as α-actinin, MLC2a and NKX2.5. This study suggested that the purification of hPSC-derived cardiomyocytes using cell sorting plates with the thermoresponsive surface is a promising method for the purification of hPSC-derived cardiomyocytes without conventional laborious processes.
  18. Ghosh P, Kumar M, Kapoor R, Kumar SS, Singh L, Vijay V, et al.
    Bioresour Technol, 2020 Jan;296:122275.
    PMID: 31683109 DOI: 10.1016/j.biortech.2019.122275
    The present study intends to evaluate the potential of co-digestion for utilizing Organic fraction of Municipal Solid Waste (OFMSW) and sewage sludge (SS) for enhanced biogas production. Metagenomic analysis was performed to identify the dominant bacteria, archaea and fungi, changes in their communities with time and their functional roles during the course of anaerobic digestion (AD). The cumulative biogas yield of 586.2 mL biogas/gVS with the highest methane concentration of 69.5% was observed under an optimum ratio of OFMSW:SS (40:60 w/w). Bacteria and fungi were found to be majorly involved in hydrolysis and initial stages of AD. Probably, the most common archaea Methanosarsina sp. primarily followed the acetoclastic pathway. The hydrogenotrophic pathway was less followed as indicated by the reduction in abundance of syntrophic acetate oxidizers. An adequate understanding of microbial communities is important to manipulate and inoculate the specific microbial consortia to maximize CH4 production through AD.
  19. Kumar SS, Hartner AM, Chandran A, Gaythorpe KAM, Li X
    BMC Public Health, 2023 Nov 28;23(1):2351.
    PMID: 38017415 DOI: 10.1186/s12889-023-17082-9
    BACKGROUND: Malaysia introduced the two dose measles-mumps-rubella (MMR) vaccine in 2004 as part of its measles elimination strategy. However, despite high historical coverage of MCV1 and MCV2, Malaysia continues to report high measles incidence. This study suggests a novel indicator for investigating population immunity against measles in the Malaysian population.

    METHODS: We define effective vaccine coverage (EVC) of measles as the proportion of a population vaccinated with measles-containing vaccine (MCV) and effectively protected against measles infection. A quantitative evaluation of EVC throughout the life course of Malaysian birth cohorts was conducted accounting for both vaccine efficacy (VE) and between-dose correlation (BdC). Measles vaccination coverage was sourced from WHO-UNICEF estimates of Malaysia's routine immunisation coverage and supplementary immunisation activities (SIAs). United Nations World population estimates and projections (UNWPP) provided birth cohort sizes stratified by age and year. A step wise joint Bernoulli distribution was used to proportionate the Malaysian population born between 1982, the first year of Malaysia's measles vaccination programme, and 2021, into individuals who received zero dose, one dose and multiple doses of MCV. VE estimates by age and doses received are then adopted to derive EVC. A sensitivity analysis was conducted using 1000 random combinations of BdC and VE parameters.

    RESULTS: This study suggests that no birth cohort in the Malaysian population has achieved > 95% population immunity (EVC) conferred through measles vaccination since the measles immunisation programme began in Malaysia.

    CONCLUSION: The persistence of measles in Malaysia is due to pockets of insufficient vaccination coverage against measles in the population. Monitoring BdC through immunisation surveillance systems may allow for the identification of susceptible subpopulations (primarily zero-dose MCV individuals) and increase the coverage of individuals who are vaccinated with multiple doses of MCV. This study provides a tool for assessment of national-level population immunity of measles conferred through vaccination and does not consider subnational heterogeneity or vaccine waning. This tool can be readily applied to other regions and vaccine-preventable diseases.

  20. Higuchi A, Ling QD, Kumar SS, Munusamy MA, Alarfaj AA, Chang Y, et al.
    Lab Invest, 2015 Jan;95(1):26-42.
    PMID: 25365202 DOI: 10.1038/labinvest.2014.132
    Induced pluripotent stem cells (iPSCs) provide a platform to obtain patient-specific cells for use as a cell source in regenerative medicine. Although iPSCs do not have the ethical concerns of embryonic stem cells, iPSCs have not been widely used in clinical applications, as they are generated by gene transduction. Recently, iPSCs have been generated without the use of genetic material. For example, protein-induced PSCs and chemically induced PSCs have been generated by the use of small and large (protein) molecules. Several epigenetic characteristics are important for cell differentiation; therefore, several small-molecule inhibitors of epigenetic-modifying enzymes, such as DNA methyltransferases, histone deacetylases, histone methyltransferases, and histone demethylases, are potential candidates for the reprogramming of somatic cells into iPSCs. In this review, we discuss what types of small chemical or large (protein) molecules could be used to replace the viral transduction of genes and/or genetic reprogramming to obtain human iPSCs.
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