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Population-specific profiling of CCL3L1 copy number of the three major ethnic groups in Malaysia and the implication on HIV susceptibility

Mohamad Isa II, Jamaluddin J, Achim NH, Abubakar S

Gene, 2020 Jun 01;754:144821.
PMID: 32497559 DOI: 10.1016/j.gene.2020.144821

CC chemokine ligand 3 like-1 (CCL3L1) encodes for CCL3L1 protein, which is a human immunodeficiency virus (HIV) suppressive chemokine and a potent ligand of HIV CCR5 co-receptor. CCL3L1 exhibits variation in the gene copy number (CN) and could influence HIV susceptibility through gene dosage effect. The study aims to determine the distribution of CCL3L1 CN among HIV subjects of Malay, Chinese, and Indian ethnics in Malaysia and to evaluate the impact of CCL3L1 CN on susceptibility to HIV. This study involved 182 HIV patients who attended outpatient clinics of three hospitals in Malaysia and 150 non-HIV (control) subjects. Typing of CCL3L1 CN was conducted via multiplex paralogue ratio tests (PRTs), followed by validation of the CCL3L1 CN by microsatellite analyses. Both Malay and Indian HIV subjects had the CN mode of two, while the CN mode for the Chinese was four. The CCL3L1 gene CN was found to be strongly associated with ethnicity (p
Fulltext Facing the challenges of multidrug-resistant Acinetobacter baumannii: progress and prospects in the vaccine development

Mat Rahim N, Lee H, Strych U, AbuBakar S

Hum Vaccin Immunother, 2021 10 03;17(10):3784-3794.
PMID: 34106809 DOI: 10.1080/21645515.2021.1927412

In 2017, the World Health Organization (WHO) named A. baumannii as one of the three antibiotic-resistant bacterial species on its list of global priority pathogens in dire need of novel and effective treatment. With only polymyxin and tigecycline antibiotics left as last-resort treatments, the need for novel alternative approaches to the control of this bacterium becomes imperative. Vaccines against numerous bacteria have had impressive records in reducing the burden of the respective diseases and addressing antimicrobial resistance; as in the case of Haemophilus influenzae type b . A similar approach could be appropriate for A. baumannii. Toward this end, several potentially protective antigens against A. baumannii were identified and evaluated as vaccine antigen candidates. A licensed vaccine for the bacteria, however, is still not in sight. Here we explore and discuss challenges in vaccine development against A. baumannii and the promising approaches for improving the vaccine development process.
Fulltext Detecting dengue outbreaks in Malaysia using geospatial techniques

Nellis S, Loong SK, Abd-Jamil J, Fauzi R, AbuBakar S

Geospat Health, 2021 11 03;16(2).
PMID: 34730321 DOI: 10.4081/gh.2021.1008

Dengue is a complex disease with an increasing number of infections worldwide. This study aimed to analyse spatiotemporal dengue outbreaks using geospatial techniques and examine the effects of the weather on dengue outbreaks in the Klang Valley area, Kuala Lumpur, Malaysia. Daily weather variables including rainfall, temperature (maximum and minimum) and wind speed were acquired together with the daily reported dengue cases data from 2001 to 2011 and converted into geospatial format to identify whether there was a specific pattern of the dengue outbreaks. The association between these variables and dengue outbreaks was assessed using Spearman's correlation. The result showed that dengue outbreaks consistently occurred in the study area during a 11-year study period. And that the strongest outbreaks frequently occurred in two high-rise apartment buildings located in Kuala Lumpur City centre. The results also show significant negative correlations between maximum temperature and minimum temperature on dengue outbreaks around the study area as well as in the area of the high-rise apartment buildings in Kuala Lumpur City centre.
Evaluation of commercial serological assays in Malaysia for detection of anti-Zika virus antibodies

Khoo HY, Lee HY, Khor CS, Tan KK, AbuBakar S

Trop Biomed, 2021 Dec 01;38(4):613-621.
PMID: 35001928 DOI: 10.47665/tb.38.4.105

The recommended test guidelines for Zika virus (ZIKV) include using both molecular and serological tools. While the molecular tools are useful for detecting acute infection, the serological tools are useful for the detection of previous infections. Nevertheless, detection of ZIKV-specific antibodies remains a challenge due to the high cross-reactivity between ZIKV and other flaviviruses such as dengue virus (DENV) and Japanese encephalitis virus (JEV). The objective of this study is to evaluate the commercially available enzyme-linked immunosorbent assay (ELISA) for the detection of ZIKV IgG. In this study, we evaluated 6 commercially available anti-ZIKV IgG ELISA kits. Pre-characterized serum panels consisting of 70 sera were selected for the evaluation. The diagnostic accuracy of each ELISA kits was determined and compared to the gold standard, Foci Reduction Neutralization Test (FRNT). The present study established that the performance of the NS1-based anti-ZIKV IgG ELISA kit was superior to that which uses of the E protein as antigen. Overall, commercial ZIKV IgG ELISA showed varying test performances, with some achieving moderate to high test sensitivities and specificities. When compared against the FRNT, the test sensitivities ranged from 7.1% to 78.6%, whereas, the test specificities ranged from 40.0% to 100%. Limitation to the study includes the cross reactivity between flavivirus and specificity of the kit in addressing the cross reactivity.
Fulltext Francisella philomiragia bacteremia in an immunocompromised patient: a rare case report

Chua HS, Soh YH, Loong SK, AbuBakar S

Ann Clin Microbiol Antimicrob, 2021 Oct 03;20(1):72.
PMID: 34602092 DOI: 10.1186/s12941-021-00475-2

BACKGROUND: Francisella philomiragia is a very rare opportunistic pathogen of humans which causes protean diseases such as pneumonia and other systemic infections. Subsequent failure of prompt treatment may result in poor prognosis with mortality among infected patients.
CASE PRESENTATION: The present report describes a case of F. philomiragia bacteraemia first reported in Malaysia and Asian in a 60-year-old patient with underlying end-stage renal disease (ESRF) and diabetes mellitus. He presented with Acute Pulmonary Oedema with Non-ST-Elevation Myocardial Infarction (NSTEMI) in our hospital. He was intubated in view of persistent type I respiratory failure and persistent desaturation despite post haemodialysis. Blood investigation indicated the presence of ongoing infection and inflammation. The aerobic blood culture growth of F. philomiragia was identified using the matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (Score value: 2.16) and confirmed by 16S Ribosomal DNA (16S rDNA) sequencing. He was discharged well on day 26 of admission, after completing one week of piperacillin/tazobactam and two weeks of doxycycline.
CONCLUSION: Clinical suspicion should be raised if patients with known risk factors are presenting with pneumonia or pulmonary nodules especially as these are the most common manifestations of F. philomiragia infection. Early diagnosis via accurate laboratory identification of the organism through MALDI-TOF mass spectrometry and molecular technique such as 16S rDNA sequencing are vital for prompt treatment that results in better outcomes for the afflicted patients.
Attitudes towards Zika screening and vaccination acceptability among pregnant women in Malaysia

Wong LP, Alias H, Hassan J, AbuBakar S

Vaccine, 2017 10 13;35(43):5912-5917.
PMID: 28886944 DOI: 10.1016/j.vaccine.2017.08.074

The aim of this study was to examine the willingness of pregnant women to have prenatal screening for the Zika virus (ZIKV). Secondly, the study also assessed the acceptability of a hypothetical Zika vaccination and its association with the health belief model (HBM) constructs. A cross-sectional study was conducted from 4th October to 11th November 2016, among pregnant women who attended antenatal care at the University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia. The majority (81.8%) was willing to be tested for ZIKV and 78% felt that their spouse would be willing to be tested for ZIKV. A total of 94% expressed a willingness to receive a Zika vaccination if available. The participants expressed high perceived benefits of a ZIKV vaccination. Although many have a high perception of the severity of ZIKV, the proportion with a strong perception of their susceptibility to ZIKV was low. In the multivariate analysis of all the HBM constructs, cue-to-action, namely physician recommendation (odds ratio [OR]=2.288; 95% confidence interval [CI] 1.093-4.793) and recommendation from friends or relatives (OR=4.030; 95% CI 1.694-9.587), were significantly associated with a willingness to be vaccinated against ZIKV. The favourable response to a Zika vaccination implies that more research attention has to be given to develop a vaccine against ZIKV. Should the vaccine be available in the future, publicity and healthcare providers would play a vital role in ensuring vaccine uptake among pregnant women.
The Self-Regulation Model of Illness: Comparison between Zika and Dengue and Its Application to Predict Mosquito Prevention Behaviours in Malaysia, a Dengue-Endemic Country

Wong LP, Alias H, Aghamohammadi N, Sam IC, AbuBakar S

Int J Environ Res Public Health, 2016 12 06;13(12).
PMID: 27929451

Perceptions about illnesses may influence self-care and preventive health behaviours. Illness perceptions of the Zika virus (ZIKV) infection were investigated under the framework of the Self-Regulation Model of Illness. Illness perception differences between ZIKV and dengue fever were also examined. Lastly, associations between illness perceptions of ZIKV with mosquito prevention practices were studied. Samples were drawn from landline telephone numbers using computer-assisted telephone interviewing in Malaysia. A total of 567 respondents completed the survey between February 2015 and May 2016. The median and interquartile range (IQR) for the total six dimensions of illness perceptions score was higher for dengue (23.0 (IQR 17.0-28.0)) than ZIKV (20.0 (IRQ 11.0-28.0)), p < 0.001. Respondents who planned to have children (OR 1.670, 95% CI 1.035-2.694 vs. no intention to have children) and had friends or acquaintances who died of dengue (OR 2.372, 95% CI 1.300-4.327 vs. no friends who died of dengue) were more likely to have a higher total score for six illness perceptions for ZIKV compared to dengue. Multivariate analysis indicated that the best predictors for mosquito control practices after the ZIKV outbreak was declared a Public Health Emergency of International Concern, in descending order, were causes, control, timeline, and consequences dimensions of illness perception. Understanding the context in which a person perceives ZIKV may contribute to developing interventions that influence prevention behaviours.
Antiadipogenic effects of a standardized quassinoids-enriched fraction and eurycomanone from Eurycoma longifolia

Balan D, Chan KL, Murugan D, AbuBakar S, Wong PF

Phytother Res, 2018 Jul;32(7):1332-1345.
PMID: 29520860 DOI: 10.1002/ptr.6065

Bioactive compounds of Eurycoma longifolia (EL) jack were previously shown to reduce omentum fat mass and oestradiol-induced fatty uterine adhesion in rats. However, the exact role of EL on adipogenesis remains unknown. This study sought to investigate the effects of an EL standardized quassinoids-enriched fraction (SQEL) and the pure compound, eurycomanone, on adipogenesis in 3T3-L1 preadipocyte cells. 3T3-L1 cells were induced to differentiate and treated for 8 days. The treatment reduced intracellular accumulation of lipid droplets and triglycerides in the differentiating adipocytes and induced lipolysis in matured adipocytes. The expressions of adipogenic transcription factors and markers were also significantly downregulated during the early stage of differentiation. Furthermore, SQEL also suppressed body weight gain, decreased epididymal and perirenal fat pad mass and size, and reduced the accumulation of fat in the livers of C57BL/6J mice fed with normal or high-fat diet that were concurrently given 5 mg/kg and 10 mg/kg (i.p) of SQEL for 12 weeks. SQEL also improved glucose intolerance and decreased the elevated total cholesterol and triglyceride levels in these mice groups. These findings suggest that SQEL could be explored as an alternative pharmacologic agent inhibiting adipogenesis for the prevention of obesity.
Fulltext Malaysian Parents' Willingness to Vaccinate Their Children against COVID-19 Infection and Their Perception of mRNA COVID-19 Vaccines

Wong LP, Lee HY, Alias H, AbuBakar S

Vaccines (Basel), 2022 Oct 25;10(11).
PMID: 36366298 DOI: 10.3390/vaccines10111790

Little was known about Malaysian parental attitudes, beliefs, and intentions surrounding coronavirus disease 2019 (COVID-19) vaccines for children when the National COVID-19 Immunization Program for Children (PICKids) was launched in February 2021. A cross-sectional online survey-based study was carried out from 15 March 2022 to 23 July 2022 on Malaysian parents/guardians of children between ages 5 and below 12 years old. A total of 15.7% reported being extremely willing, and 38.9% were somewhat willing to vaccinate children with a COVID-19 vaccine. Perceived low susceptibility to COVID-19 infection showed the greatest significant impact on vaccine acceptance (OR 35.46, 95% CI 15.26-82.40). Parents with a lower level of concern have a higher willingness for vaccination (OR 1.25, 95% CI 0.90-1.75). Of the parents that knew of the mRNA vaccine, 46.6% reported that they prefer their children to be vaccinated with conventional vaccines over mRNA vaccines. Poor knowledge about mRNA vaccines, lack of confidence in the mRNA technology, fear of unknown side effects, and perception that the mRNA vaccines contain microchips were significantly associated with a higher level of concern about their children receiving an mRNA vaccine. Public education campaigns to promote COVID-19 vaccination for children warrant addressing the concerns and knowledge deficits among vaccine-hesitant parents.
Lactic acid bacteria waste infusion as a source of attraction and oviposition stimulation of gravid female Aedes albopictus mosquitoes

Suria MM, Yap PC, Lov VL, AbuBakar S, Lee HY

Trop Biomed, 2022 Dec 01;39(4):499-503.
PMID: 36602207 DOI: 10.47665/tb.39.4.004

Aedes albopictus poses a public health risk in tropical countries and temperate countries in recent decades due to its capability to transmit various human arboviruses including dengue, yellow fever, and chikungunya. Vector control is the key for preventing transmission of these pathogenic viruses. Improving the effectiveness of currently utilized collection methods, such as ovitraps, is important for best species abundance monitoring, assessment of the threat of arbovirus transmission, and optimizing control activities. Therefore, this study aimed to assess the potential use of lactic acid bacteria (LAB) waste as an infusion-baited ovitrap for Aedes collection. The performance of overnight tap water, grass hay infusion and LAB waste infusion were compared for their ability in attracting gravid female Ae. albopictus. In this study, the LAB waste infusion was substantially more alluring to Ae. albopictus mosquitoes than the two controls grass hay infusion and tap water.
Has Zika Been Forgotten? Findings From Nationwide Survey on Knowledge, Attitudes, and Mosquito Preventive Practices in Malaysia

Wong LP, Alias H, Lee HY, AbuBakar S

Disaster Med Public Health Prep, 2022 Apr 11;17:e131.
PMID: 35400356 DOI: 10.1017/dmp.2022.40

OBJECTIVE: The aim of this study is to assess knowledge and attitudes toward Zika virus disease (ZVD) as well as mosquito prevention practices in Malaysia at a nationwide level.
METHODS: Computer-assisted telephone interviews (CATI) were conducted between June 2019 and February 2020.
RESULTS: There are gaps in knowledge about the symptoms, mode of transmission, and risk of microcephaly. The mean for the Zika-related knowledge score was 5.9 (SD ± 4.4) out of a possible score of 14. The majority perceived little or no risk of getting ZVD (75.0%) and 75.5% were a little or not at all worried about ZVD. A high proportion reported the use of insect sprays or mosquito coils to prevent mosquito bites; however, a relatively lower proportion of people reported fixing mosquito netting on doors and windows, and using mosquito bed nets. The mean for the mosquito prevention practices score was 11.9 (SD ± 4.7) out of a possible score of 27. Important factors influencing mosquito prevention practices include household income, environment factors, risk perception, and Zika-related knowledge.
CONCLUSION: Zika prevention measures should be targeted in priority toward residents in lower socioeconomic neighborhoods. Campaigns should focus on messages highlighting the high risk of getting dengue.
Fulltext Genomic species identification of Acinetobacter of clinical isolates by 16S rDNA sequencing

Misbah S, Hassan H, Yusof MY, Hanifah YA, AbuBakar S

Singapore Med J, 2005 Sep;46(9):461-4.
PMID: 16123830

This study aims to identify Acinetobacter of clinical isolates from the University of Malaya Medical Centre (UMMC), Kuala Lumpur, to the species level by 16S rDNA sequencing.
Antibiotic susceptibility and REP-PCR fingerprints of Acinetobacter spp. isolated from a hospital ten years apart

Misbah S, AbuBakar S, Hassan H, Hanifah YA, Yusof MY

J Hosp Infect, 2004 Dec;58(4):254-61.
PMID: 15564001

The antibiotic susceptibility profiles and the repetitive extragenic palindromic sequence-based polymerase chain reaction (REP-PCR)-determined genotypes of 109 Acinetobacter strains collected from the University Malaya Medical Center (UMMC), Kuala Lumpur, Malaysia, in 1987 (N=21) and 1996-1998 (N=88) were established. Twelve antibiotic susceptibility profiles of antibiotics used at the UMMC were obtained. In descending order of effectiveness, imipenem, amikacin and ciprofloxacin were the most effective against the Acinetobacter strains. Compared with 1987 isolates, the isolates obtained in 1996-1998 had decreased susceptibility to these antibiotics and were tolerant to the antibiotics up to an MIC90 of > or =256 mg/L. REP-PCR DNA fingerprints of all the isolates revealed the presence of four Acinetobacter spp. lineages; 92% of all the isolates belonged to two dominant lineages (genotypes 1 and 4). Genotype 4 isolates predominant in 1987 showed increased resistance and antibiotic tolerance to imipenem, amikacin and ciprofloxacin compared with the 1996-1998 isolates. In contrast, genotype 1 isolates from 1996-1998 were mainly sensitive to these antibiotics. These findings demonstrate the presence of at least two independent Acinetobacter spp. lineages in the same hospital, and suggest the possibility that genotype 4 Acinetobacter spp. acquired the resistance phenotype in situ, whereas most of the genotype 1 isolates were probably introduced to the hospital in recent years.
Investigating the potential of mono-chalcone compounds in targeting breast cancer receptors through network pharmacology, molecular docking, molecular dynamics simulation, antiproliferative effects, and gene expressions

Ismail NZ, Khairuddean M, Alidmat MM, Abubakar S, Arsad H

3 Biotech, 2024 Jun;14(6):151.
PMID: 38737798 DOI: 10.1007/s13205-024-03991-y

The study aims to investigate various aspects of synthesized mono-chalcone compounds 5 and 8 concerning breast cancer, including network pharmacology, molecular docking, molecular dynamics (MD) simulations, antiproliferative effects, and gene expressions. Initially, the compounds underwent a network pharmacology analysis targeting breast cancer-related targets, with MalaCards, SwissTargetPrediction, and PharmMapper identifying 70 breast cancer target receptors. Subsequently, protein-protein interaction (PPI) network analysis revealed two distinct target gene clusters. Survival analysis identified seven significant target genes following Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and Gene Ontology (GO) evaluation. Molecular docking and MD simulations were conducted on these seven target genes (AKT2, BRAF, ESR1, FGFR1, IGF1, IGF1R, and KIT), revealing that compound 8 exhibited the highest binding affinities, as well as better stability and compactness when interacting with the targeted proteins. Next, the compounds underwent cell viability assay and gene expression analysis to validate the in silico findings. Both compounds demonstrated the ability to suppress breast cancer proliferation, with compound 8 showing increased selectivity in targeting breast cancer cells while causing minimal harm to normal breast cells. The suppression of breast cancer cell proliferation was attributed to decreased expression levels of AKT2, BRAF, FGFR1, IGF1, IGF1R, KIT, and ESR1. Hence, the results provide insights into the molecular interaction responsible for the anti-breast cancer capabilities of mono-chalcone compounds.
SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-024-03991-y.
Fulltext Overview of anti-viral effects of probiotics via immune cells in pre-, mid- and post-SARS-CoV2 era

Kanauchi O, Low ZX, Jounai K, Tsuji R, AbuBakar S

Front Immunol, 2023;14:1280680.
PMID: 38116008 DOI: 10.3389/fimmu.2023.1280680

The COVID-19 outbreak has caused significant global changes and increased public awareness of SARS-CoV-2. Substantial progress in developing vaccines, enhancing sanitation practices, and implementing various measures to combat the virus, including the utilization of probiotics has been made. This comprehensive review examined the medical impact of clinically proven probiotics on infectious diseases, considering three crucial time periods: before (pre-), during (mid-), and after (post-) COVID-19 pandemic era. This review also showed a perspective on the use of probiotics to stimulate the innate immune system and prevent infectious diseases. In pre-COVID-19 era, several probiotic strains were found to be clinically effective in addressing gastrointestinal infectious diseases, the common cold and flu. However, the mechanism by which probiotics exerted their antiviral effects remained relatively unclear during that period. Nevertheless, probiotics, Lactococcus lactis strain Plasma (LC-Plasma), and others have gained attention for their unique ability to modulate the immune system and demonstrate antiviral properties. While some probiotics have shown promise in alleviating gastrointestinal symptoms linked to COVID-19, their direct effectiveness in treating or preventing COVID-19 progression has not yet been conclusively established. As we transition into the post-COVID-19 era, the relationship between COVID-19 and plasmacytoid dendritic cells (pDCs), a vital component of the innate immune system, has been gradually elucidated. These findings are now being applied in developing novel vaccines and treatments involving interferons and in immune activation research using probiotics as adjuvants, comparable to CpG-DNA through TLR9. The role of the local innate immune system, including pDCs, as the first line of defense against viral infections has gained increasing interest. Moving forward, insight of the immune system and the crosstalk between probiotics and the innate immune system is expected to highlight the role of probiotics in adjunctive immunoregulatory therapy. In combination with drug treatments, probiotics may play a more substantial role in enhancing immune responses. The immunoregulatory approach using probiotics such as LC-Plasma, which can induce anti-infectious factors such as interferons, holds promise as a viable therapeutic and prophylactic option against viral infectious diseases due to their good safety profile and protective efficacy.
Fulltext Virus-specific read-through codon preference affects infectivity of chimeric cucumber green mottle mosaic viruses displaying a dengue virus epitope

Teoh PG, Ooi AS, AbuBakar S, Othman RY

J Biomed Biotechnol, 2009;2009:781712.
PMID: 19325913 DOI: 10.1155/2009/781712

A Cucumber green mottle mosaic virus (CGMMV) was used to present a truncated dengue virus type 2 envelope (E) protein binding region from amino acids 379 to 423 (EB4). The EB4 gene was inserted at the terminal end of the CGMMV coat protein (CP) open reading frame (ORF). Read-through sequences of TMV or CGMMV, CAA-UAG-CAA-UUA, or AAA-UAG-CAA-UUA were, respectively, inserted in between the CP and the EB4 genes. The chimeric clones, pRT, pRG, and pCG+FSRTRE, were transcribed into full-length capped recombinant CGMMV transcripts. Only constructs with the wild-type CGMMV read-through sequence yielded infectious viruses following infection of host plant, muskmelon (Cucumis melo) leaves. The ratio of modified to unmodified CP for the read-through expression clone developed was also found to be approximately 1:1, higher than what has been previously reported. It was also observed that infectivity was not affected by differences in pI between the chimera and its wild counterpart. Analysis of recombinant viruses after 21-days-postinculation (dpi) revealed that deletions occurred resulting in partial reversions of the viral population to near wild type and suggesting that this would be the limiting harvest period for obtaining true to type recombinants with this construct.
Fulltext Hepatoprotective Effects of Chinese Medicine Herbs Decoction on Liver Cirrhosis in Rats

Mat-Rahim NA, Lim TH, Nor-Amdan NA, AbuBakar S

Evid Based Complement Alternat Med, 2017;2017:6125829.
PMID: 28280515 DOI: 10.1155/2017/6125829

Hepatoprotective and curative activities of aqueous extract of decoction containing 10 Chinese medicinal herbs (HPE-XA-08) were evaluated in Sprague-Dawley albino rats with liver damage induced by thioacetamide (TAA). These activities were assessed by investigating the liver enzymes level and also histopathology investigation. Increases in alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT) levels were observed in rats with cirrhotic liver. No significant alterations of the liver enzymes were observed following treatment with HPE-XA-08. Histopathology examination of rats treated with HPE-XA-08 at 250 mg/kg body weight, however, exhibited moderate liver protective effects. Reduced extracellular matrix (ECM) proteins within the hepatocytes were noted in comparison to the cirrhotic liver. The curative effects of HPE-XA-08 were observed with marked decrease in the level of ALP (more than 3x) and level of GGT (more than 2x) in cirrhotic rat treated with 600 mg/kg body weight HPE-XA-08 in comparison to cirrhotic rat treated with just water diluent. Reversion of cirrhotic liver to normal liver condition in rats treated with HPE-XA-08 was observed. Results from the present study suggest that HPE-XA-08 treatment assisted in the protection from liver cirrhosis and improved the recovery of cirrhotic liver.
Virus Propagation and Cell-Based Colorimetric Quantification

Tan JY, Wong JE, Zainal N, AbuBakar S, Tan KK

J Vis Exp, 2023 Apr 07.
PMID: 37092849 DOI: 10.3791/64578

Zika virus (ZIKV) is a mosquito-borne virus belonging to the genus Flavivirus. ZIKV infection has been associated with congenital brain abnormalities and potentially Guillain-Barré syndrome in adults. Research on ZIKV to understand the disease mechanisms is important to facilitate vaccine and treatment development. The method of quantifying viruses is crucial and fundamental in the field of virology. The focus forming assay (FFA) is a virus quantification assay that detects the viral antigen with antibodies and identifies the infection foci of cells using the peroxidase immunostaining technique. The current study describes the virus propagation and quantification protocol using both 24-well and 96-well (high throughput) formats. Compared with other similar studies, this protocol has further described foci size optimization, which can serve as a guide to expand the use of this assay for other viruses. Firstly, ZIKV propagation is performed in Vero cells for 3 days. The culture supernatant containing ZIKV is harvested and quantitated using the FFA. Briefly, the virus culture is inoculated onto Vero cells and incubated for 2-3 days. Foci formation is then determined after optimized staining processes, including cell fixation, permeabilization, blocking, antibody binding, and incubation with peroxidase substrate. The stained virus foci are visualized using a stereo microscope (manual counting in 24-well format) or software analyzer (automated counting in 96-well format). The FFA provides reproducible, relatively fast results (3-4 days) and is suitable to be used for different viruses, including non-plaque-forming viruses. Subsequently, this protocol is useful for the study of ZIKV infection and could be used to detect other clinically important viruses.
Monitoring Changes in Human Umbilical Vein Endothelial Cells upon Viral Infection Using Impedance-Based Real-Time Cell Analysis

Wong JE, Zainal N, AbuBakar S, Tan KK

J Vis Exp, 2023 May 05.
PMID: 37212555 DOI: 10.3791/64887

Endothelial cells line the inner surface of all blood and lymphatic vessels, creating a semi-permeable barrier regulating fluid and solute exchange between blood or lymph and their surrounding tissues. The ability of a virus to cross the endothelial barrier is an important mechanism that facilitates virus dissemination in the human body. Many viruses are reported to alter endothelial permeability and/or cause endothelial cell barrier disruption during infection, which is able to cause vascular leakage. The current study describes a real-time cell analysis (RTCA) protocol, using a commercial real-time cell analyzer to monitor endothelial integrity and permeability changes during Zika virus (ZIKV) infection of the human umbilical vein endothelial cells (HUVECs). The impedance signals recorded before and after ZIKV infection were translated to cell index (CI) values and analyzed. The RTCA protocol allows the detection of transient effects in the form of cell morphological changes during a viral infection. This assay could also be useful for studying changes in the vascular integrity of HUVECs in other experimental setups.
Fulltext Isolation of ancestral sylvatic dengue virus type 1, Malaysia

Teoh BT, Sam SS, Abd-Jamil J, AbuBakar S

Emerg Infect Dis, 2010 Nov;16(11):1783-5.
PMID: 21029545 DOI: 10.3201/eid1611.100721

Ancestral sylvatic dengue virus type 1, which was isolated from a monkey in 1972, was isolated from a patient with dengue fever in Malaysia. The virus is neutralized by serum of patients with endemic DENV-1 infection. Rare isolation of this virus suggests a limited spillover infection from an otherwise restricted sylvatic cycle.

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