MyMedR

Displaying publications 1 - 20 of 104 in total

Abstract:

Sort:

Fulltext Simian malaria in wild macaques: first report from Hulu Selangor district, Selangor, Malaysia

Akter R, Vythilingam I, Khaw LT, Qvist R, Lim YA, Sitam FT, et al.

Malar J, 2015 Oct 05;14:386.
PMID: 26437652 DOI: 10.1186/s12936-015-0856-3

BACKGROUND: Malaria is a vector-borne parasitic disease which is prevalent in many developing countries. Recently, it has been found that Plasmodium knowlesi, a simian malaria parasite can be life-threatening to humans. Long-tailed macaques, which are widely distributed in Malaysia, are the natural hosts for simian malaria, including P. knowlesi. The aim of the present study was to determine the prevalence of simian malaria parasites in long-tailed macaques in the district of Hulu Selangor, Selangor, Malaysia.
METHODS: A total of 70 blood samples were collected from Macaca fascicularis dwelling in the forest of Hulu Selangor by the Department of Wildlife and National Parks Peninsular Malaysia, Kuala Lumpur, Malaysia. DNA was extracted using PureLink™ Genomic DNA Kits. Conventional and nested PCR were used to detect the genus and species of Plasmodium parasites respectively. In addition, phylogenetic analysis was carried out to confirm the species of Plasmodium parasites.
RESULTS: Thirty-five (50 %) of the 70 samples were positive for Plasmodium using genus-specific primers. These positive samples were then subjected to nested PCR targeting the 18S ribosomal RNA genes to detect all five simian malaria parasites: namely, P. knowlesi, Plasmodium inui, Plasmodium cynomolgi, Plasmodium fieldi, and Plasmodium coatneyi. All five species of simian malaria parasites were detected. Of these, P. inui was the predominant (65.7 %), followed by P. knowlesi (60 %), P. cynomolgi (51.4 %) P. coatneyi (45.7 %) and P. fieldi (2.9 %). A total of nine macaques had mono-infection with P. knowlesi (four), P. cynomolgi (two), P. coatneyi (two) and P. fieldi (one). Eleven of the macaques had dual infections while 12 had triple infections. Three macaques were infected with four species of Plasmodium. Molecular and phylogenetic analysis confirmed the five species of Plasmodium parasites.
CONCLUSION: This study has provided evidence to elucidate the presence of transmission of malaria parasites among the local macaques in Hulu Selangor. Since malaria is a zoonosis, it is important to determine the new control strategies for the control of malaria.
Japanese encephalitis virus disrupts blood-brain barrier and modulates apoptosis proteins in THBMEC cells

Al-Obaidi MMJ, Bahadoran A, Har LS, Mui WS, Rajarajeswaran J, Zandi K, et al.

Virus Res, 2017 04 02;233:17-28.
PMID: 28279803 DOI: 10.1016/j.virusres.2017.02.012

Japanese encephalitis (JE) is a neurotropic flavivirus that causes inflammation in central nervous system (CNS), neuronal death and also compromises the structural and functional integrity of the blood-brain barrier (BBB). The aim of this study was to evaluate the BBB disruption and apoptotic process in Japanese encephalitis virus (JEV)-infected transfected human brain microvascular endothelial cells (THBMECs). THBMECs were overlaid by JEV with different MOIs (0.5, 1.0, 5.0 and 10.0) and monitored by electrical cell-substrate impedance sensing (ECIS) in a real-time manner in order to observe the barrier function of THBMECs. Additionally, the level of 43 apoptotic proteins was quantified in the virally infected cells with different MOIs at 24h post infection. Infection of THBMEC with JEV induced an acute reduction in transendothelial electrical resistance (TEER) after viral infection. Also, significant up-regulation of Bax, BID, Fas and Fasl and down-regulation of IGFBP-2, BID, p27 and p53 were observed in JEV infected THBMECs with 0.5 and 10 MOIs compared to uninfected cells. Hence, the permeability of THBMECs is compromised during the JEV infection. In addition high viral load of the virus has the potential to subvert the host cell apoptosis to optimize the course of viral infection through deactivation of pro-apoptotic proteins.
Fulltext Inhibition of dengue virus entry into target cells using synthetic antiviral peptides

Alhoot MA, Rathinam AK, Wang SM, Manikam R, Sekaran SD

Int J Med Sci, 2013;10(6):719-29.
PMID: 23630436 DOI: 10.7150/ijms.5037

Despite the importance of DENV as a human pathogen, there is no specific treatment or protective vaccine. Successful entry into the host cells is necessary for establishing the infection. Recently, the virus entry step has become an attractive therapeutic strategy because it represents a barrier to suppress the onset of the infection. Four putative antiviral peptides were designed to target domain III of DENV-2 E protein using BioMoDroid algorithm. Two peptides showed significant inhibition of DENV when simultaneously incubated as shown by plaque formation assay, RT-qPCR, and Western blot analysis. Both DET4 and DET2 showed significant inhibition of virus entry (84.6% and 40.6% respectively) using micromolar concentrations. Furthermore, the TEM images showed that the inhibitory peptides caused structural abnormalities and alteration of the arrangement of the viral E protein, which interferes with virus binding and entry. Inhibition of DENV entry during the initial stages of infection can potentially reduce the viremia in infected humans resulting in prevention of the progression of dengue fever to the severe life-threatening infection, reduce the infected vector numbers, and thus break the transmission cycle. Moreover these peptides though designed against the conserved region in DENV-2 would have the potential to be active against all the serotypes of dengue and might be considered as Hits to begin designing and developing of more potent analogous peptides that could constitute as promising therapeutic agents for attenuating dengue infection.
Fulltext RNA interference mediated inhibition of dengue virus multiplication and entry in HepG2 cells

Alhoot MA, Wang SM, Sekaran SD

PLoS One, 2012;7(3):e34060.
PMID: 22457813 DOI: 10.1371/journal.pone.0034060

Dengue virus-host cell interaction initiates when the virus binds to the attachment receptors followed by endocytic internalization of the virus particle. Successful entry into the cell is necessary for infection initiation. Currently, there is no protective vaccine or antiviral treatment for dengue infection. Targeting the viral entry pathway has become an attractive therapeutic strategy to block infection. This study aimed to investigate the effect of silencing the GRP78 and clathrin-mediated endocytosis on dengue virus entry and multiplication into HepG2 cells.
Fulltext Inhibition of dengue virus entry and multiplication into monocytes using RNA interference

Alhoot MA, Wang SM, Sekaran SD

PLoS Negl Trop Dis, 2011 Nov;5(11):e1410.
PMID: 22140591 DOI: 10.1371/journal.pntd.0001410

Dengue infection ranks as one of the most significant viral diseases of the globe. Currently, there is no specific vaccine or antiviral therapy for prevention or treatment. Monocytes/macrophages are the principal target cells for dengue virus and are responsible for disseminating the virus after its transmission. Dengue virus enters target cells via receptor-mediated endocytosis after the viral envelope protein E attaches to the cell surface receptor. This study aimed to investigate the effect of silencing the CD-14 associated molecule and clathrin-mediated endocytosis using siRNA on dengue virus entry into monocytes.
Fulltext Dengue Virus NS1 Protein as a Diagnostic Marker: Commercially Available ELISA and Comparison to qRT-PCR and Serological Diagnostic Assays Currently Used by the State of Florida

Ambrose JH, Sekaran SD, Azizan A

J Trop Med, 2017;2017:8072491.
PMID: 28740517 DOI: 10.1155/2017/8072491

BACKGROUND: The proper management of patients infected with dengue virus requires early detection. Here, real-time molecular assays have proven useful but have limitations, whereas ELISAs that detect antibodies are still favored but results are obtained too late to be of clinical value. The production of DENV NS1 peaks early during infection and its detection can combine the advantages of both diagnostic approaches.
METHODS: This study compared assays currently used for detecting DENV infection at the Florida Department of Health including anti-DENV IgM and IgG ELISAs as well as qRT-PCR, against a commercially available DENV NS1 ELISA. These comparisons were made among a group of 21 human sera.
RESULTS: Nine of 14 (64.3%) DENV qRT-PCR+ samples were also DENV NS1+. Interestingly, the 5 NS1- samples that were qRT-PCR+ were additionally IgM- and IgG+ suggesting a nonprimary infection. Compared to qRT-PCR, the NS1 assay had a sensitivity of 64.3%, specificity 100%, PPV of 100%, and NPV of 58.3%.
CONCLUSIONS: The NS1 ELISA performed as expected in known DENV qRT-PCR+ samples; however negative NS1 results for qRT-PCR+ and IgG+ sera seemingly reduced the usefulness of the NS1 ELISA for nonprimary cases. We therefore conclude that diagnosis obtained via DENV NS1 ELISA deserves further investigation.
Fulltext Corrigendum to "Dengue Virus NS1 Protein as a Diagnostic Marker: Commercially Available ELISA and Comparison to qRT-PCR and Serological Diagnostic Assays Currently Used by the State of Florida"

Ambrose JH, Sekaran SD, Azizan A

J Trop Med, 2017;2017:2046864.
PMID: 29209371 DOI: 10.1155/2017/2046864

[This corrects the article DOI: 10.1155/2017/8072491.].
Fulltext Detection of quorum sensing signal molecules and identification of an autoinducer synthase gene among biofilm forming clinical isolates of Acinetobacter spp

Anbazhagan D, Mansor M, Yan GO, Md Yusof MY, Hassan H, Sekaran SD

PLoS One, 2012;7(7):e36696.
PMID: 22815678 DOI: 10.1371/journal.pone.0036696

Quorum sensing is a term that describes an environmental sensing system that allows bacteria to monitor their own population density which contributes significantly to the size and development of the biofilm. Many gram negative bacteria use N-acyl-homoserine lactones as quorum sensing signal molecules. In this study, we sought to find out if the biofilm formation among clinical isolates of Acinetobacter spp. is under the control of autoinducing quorum sensing molecules.
Fulltext Development of conventional and real-time multiplex PCR assays for the detection of nosocomial pathogens

Anbazhagan D, Mui WS, Mansor M, Yan GO, Yusof MY, Sekaran SD

Braz J Microbiol, 2011 Apr;42(2):448-58.
PMID: 24031653 DOI: 10.1590/S1517-83822011000200006

Nosocomial infections are major clinical threats to hospitalised patients and represent an important source of morbidity and mortality. It is necessary to develop rapid detection assays of nosocomial pathogens for better prognosis and initiation of antimicrobial therapy in patients. In this study, we present the development of molecular methods for the detection of six common nosocomial pathogens including Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter spp. Conventional multiplex PCR and SYBR Green based real time PCR assays were performed using genus and species specific primers. Blind testing with 300 clinical samples was also carried out. The two assays were found to be sensitive and specific. Eubacterial PCR assay exhibited positive results for 46 clinical isolates from which 43 samples were detected by real time PCR assay. The sensitivity of the assay is about 93.7% in blind test isolates. The PCR results were reconfirmed using the conventional culture method. This assay has the potential to be a rapid, accurate and highly sensitive molecular diagnostic tool for simultaneous detection of Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter spp. This assay has the potential to detect nosocomial pathogens within 5 to 6 hours, helping to initiate infection control measures and appropriate treatment in paediatric and elderly (old aged) patients, pre-and post surgery patients and organ transplant patients and thus reduces their hospitalization duration.
Fulltext Cytokine factors present in dengue patient sera induces alterations of junctional proteins in human endothelial cells

Appanna R, Wang SM, Ponnampalavanar SA, Lum LC, Sekaran SD

Am J Trop Med Hyg, 2012 Nov;87(5):936-42.
PMID: 22987650 DOI: 10.4269/ajtmh.2012.11-0606

Plasma leakage in severe dengue has been postulated to be associated with skewed cytokine immune responses. In this study, the association of cytokines with vascular permeability in dengue patients was investigated. Human serum samples collected from 48 persons (13 with dengue fever, 29 with dengue hemorrhagic fever, and 6 healthy) were subjected to cytokines analysis by using Luminex Multiplex Technology. Selected serum samples from patients with dengue hemorrhagic fever sera and recombinant human cytokines were then tested for roles on inducing vascular permeability by treatment of human umbilical vein endothelial cells. Confocal immunofluorescence staining indicated morphologic alteration of human umbilical vein endothelial cells treated with serum samples from patients with dengue hemorrhagic fever compared with serum samples from healthy persons. The findings suggest that cytokines produced during dengue hemorrhagic infections could induce alterations in the vascular endothelium, which may play a fundamental role in the pathophysiology of dengue.
Fulltext Susceptible and protective HLA class 1 alleles against dengue fever and dengue hemorrhagic fever patients in a Malaysian population

Appanna R, Ponnampalavanar S, Lum Chai See L, Sekaran SD

PLoS One, 2010;5(9).
PMID: 20927388 DOI: 10.1371/journal.pone.0013029

The human leukocyte antigen alleles have been implicated as probable genetic markers in predicting the susceptibility and/or protection to severe manifestations of dengue virus (DENV) infection. In this present study, we aimed to investigate for the first time, the genotype variants of HLA Class 1(-A and -B) of DENV infected patients against healthy individuals in Malaysia.
The antioxidant effect of the Malaysian Gelam honey on pancreatic hamster cells cultured under hyperglycemic conditions

Batumalaie K, Qvist R, Yusof KM, Ismail IS, Sekaran SD

Clin Exp Med, 2014 May;14(2):185-95.
PMID: 23584372 DOI: 10.1007/s10238-013-0236-7

Type 2 diabetes consists of progressive hyperglycemia, insulin resistance, and pancreatic β-cell failure which could result from glucose toxicity, inflammatory cytokines, and oxidative stress. In the present study, we investigate the effect of pretreatment with Gelam honey (Melaleuca spp.) and the individual flavonoid components chrysin, luteolin, and quercetin, on the production of reactive oxygen species (ROS), cell viability, lipid peroxidation, and insulin content in hamster pancreatic cells (HIT-T15 cells), cultured under normal and hyperglycemic conditions. Phenolic extracts from a local Malaysian species of Gelam honey (Melaleuca spp.) were prepared using the standard extraction methods. HIT-T15 cells were cultured in 5 % CO2 and then preincubated with Gelam honey extracts (20, 40, 60, and 80 μg/ml) as well as some of its flavonoid components chrysin, luteolin, and quercetin (20, 40, 60, and 80 μM), prior to stimulation by 20 and 50 mM of glucose. The antioxidative effects were measured in these cultured cells at different concentrations and time point by DCFH-DA assay. Pretreatment of cells with Gelam honey extract or the flavonoid components prior to culturing in 20 or 50 mM glucose showed a significant decrease in the production of ROS, glucose-induced lipid peroxidation, and a significant increase in insulin content and the viability of cells cultured under hyperglycemic condition. Our results show the in vitro antioxidative property of the Gelam honey and the flavonoids on the β-cells from hamsters and its cytoprotective effect against hyperglycemia.
Fulltext Evaluation of the Diagnostic Accuracy of a New Biosensors-Based Rapid Diagnostic Test for the Point-Of-Care Diagnosis of Previous and Recent Dengue Infections in Malaysia

Chong ZL, Soe HJ, Ismail AA, Mahboob T, Chandramathi S, Sekaran SD

Biosensors (Basel), 2021 Apr 22;11(5).
PMID: 33921935 DOI: 10.3390/bios11050129

Dengue is a major threat to public health globally. While point-of-care diagnosis of acute/recent dengue is available to reduce its mortality, a lack of rapid and accurate testing for the detection of previous dengue remains a hurdle in expanding dengue seroepidemiological surveys to inform its prevention, especially vaccination, to reduce dengue morbidity. This study evaluated ViroTrack Dengue Serostate, a biosensors-based semi-quantitative anti-dengue IgG (immunoglobulin G) immuno-magnetic agglutination assay for the diagnosis of previous and recent dengue in a single test. Blood samples were obtained from 484 healthy participants recruited randomly from two communities in Petaling district, Selangor, Malaysia. The reference tests were Panbio Dengue IgG indirect and capture enzyme-linked immunosorbent assays, in-house hemagglutination inhibition assay, and focus reduction neutralization test. Dengue Serostate had a sensitivity and specificity of 91.1% (95%CI 87.8-93.8) and 91.1% (95%CI 83.8-95.8) for the diagnosis of previous dengue, and 90.2% (95%CI 76.9-97.3) and 93.2% (95%CI 90.5-95.4) for the diagnosis of recent dengue, respectively. Its positive predictive value of 97.5% (95%CI 95.3-98.8) would prevent most dengue-naïve individuals from being vaccinated. ViroTrack Dengue Serostate's good point-of-care diagnostic accuracy can ease the conduct of dengue serosurveys to inform dengue vaccination strategy and facilitate pre-vaccination screening to ensure safety.
Fulltext Diagnostic accuracy and utility of three dengue diagnostic tests for the diagnosis of acute dengue infection in Malaysia

Chong ZL, Sekaran SD, Soe HJ, Peramalah D, Rampal S, Ng CW

BMC Infect Dis, 2020 Mar 12;20(1):210.
PMID: 32164538 DOI: 10.1186/s12879-020-4911-5

BACKGROUND: Dengue is an emerging infectious disease that infects up to 390 million people yearly. The growing demand of dengue diagnostics especially in low-resource settings gave rise to many rapid diagnostic tests (RDT). This study evaluated the accuracy and utility of ViroTrack Dengue Acute - a new biosensors-based dengue NS1 RDT, SD Bioline Dengue Duo NS1/IgM/IgG combo - a commercially available RDT, and SD Dengue NS1 Ag enzyme-linked immunosorbent assay (ELISA), for the diagnosis of acute dengue infection.
METHODS: This prospective cross-sectional study consecutively recruited 494 patients with suspected dengue from a health clinic in Malaysia. Both RDTs were performed onsite. The evaluated ELISA and reference tests were performed in a virology laboratory. The reference tests comprised of a reverse transcription-polymerase chain reaction and three ELISAs for the detection of dengue NS1 antigen, IgM and IgG antibodies, respectively. The diagnostic performance of evaluated tests was computed using STATA version 12.
RESULTS: The sensitivity and specificity of ViroTrack were 62.3% (95%CI 55.6-68.7) and 95.0% (95%CI 91.7-97.3), versus 66.5% (95%CI 60.0-72.6) and 95.4% (95%CI 92.1-97.6) for SD NS1 ELISA, and 52.4% (95%CI 45.7-59.1) and 97.7% (95%CI 95.1-99.2) for NS1 component of SD Bioline, respectively. The combination of the latter with its IgM and IgG components were able to increase test sensitivity to 82.4% (95%CI 76.8-87.1) with corresponding decrease in specificity to 87.4% (95%CI 82.8-91.2). Although a positive test on any of the NS1 assays would increase the probability of dengue to above 90% in a patient, a negative result would only reduce this probability to 23.0-29.3%. In contrast, this probability of false negative diagnosis would be further reduced to 14.7% (95%CI 11.4-18.6) if SD Bioline NS1/IgM/IgG combo was negative.
CONCLUSIONS: The performance of ViroTrack Dengue Acute was comparable to SD Dengue NS1 Ag ELISA. Addition of serology components to SD Bioline Dengue Duo significantly improved its sensitivity and reduced its false negative rate such that it missed the fewest dengue patients, making it a better point-of-care diagnostic tool. New RDT like ViroTrack Dengue Acute may be a potential alternative to existing RDT if its combination with serology components is proven better in future studies.
Immunofluorescence-based biosensor for the determination of dengue virus NS1 in clinical samples

Darwish NT, Sekaran SD, Alias Y, Khor SM

J Pharm Biomed Anal, 2018 Feb 05;149:591-602.
PMID: 29197806 DOI: 10.1016/j.jpba.2017.11.064

The sharp increase in incidence of dengue infection has necessitated the development of methods for the rapid diagnosis of this deadly disease. Here we report the design and development of a reliable, sensitive, and specific optical immunosensor for the detection of the dengue nonstructural protein 1 (NS1) biomarker in clinical samples obtained during early stages of infection. The present optical NS1 immunosensor comprises a biosensing surface consisting of specific monoclonal NS1 antibody for immunofluorescence-based NS1 antigen determination using fluorescein isothiocyanate (FITC) conjugated to IgG antibody. The linear range of the optical immunosensor was from 15-500ngmL-1, with coefficient of determination (R2) of 0.92, high reproducibility (the relative standard deviation obtained was 2%), good stability for 21days at 4°C, and low detection limit (LOD) at 15ngmL-1. Furthermore, the optical immunosensor was capable of detecting NS1 analytes in plasma specimens from patients infected with the dengue virus, with low cross-reaction with plasma specimens containing the Japanese encephalitis virus (JEV) and Zika virus. No studies have been performed on the reproducibility and cross-reactivity regarding NS1 specificity, which is thus a limitation for optical NS1 immunosensors. In contrast, the present study addressed these limitations carefully where these two important experiments were conducted to showcase the robustness of our newly developed optical-based fluorescence immunosensor, which can be practically used for direct NS1 determination in any untreated clinical sample.
Distribution of CBP genes in Streptococcus pneumoniae isolates in relation to vaccine types, penicillin susceptibility and clinical site

Desa MN, Sekaran SD, Vadivelu J, Parasakthi N

Epidemiol Infect, 2008 Jul;136(7):940-2.
PMID: 17678563

Choline-binding proteins (CBP) have been associated with the pathogenesis of Streptococcus pneumoniae. We screened, using PCR, for the presence of genes (cbpA, D, E, G) encoding these proteins in 34 isolates of pneumococci of known serotypes and penicillin susceptibility from invasive and non-invasive disease. All isolates harboured cbpD and cbpE whereas cbpA and cbpG were found in 47% and 59% respectively; the latter were more frequent in vaccine-associated types and together accounted for 77% of these isolates. No association was observed with penicillin susceptibility but 85% of non-invasive isolates were positive for these genes.
Fulltext C-phycocyanin confers protection against oxalate-mediated oxidative stress and mitochondrial dysfunctions in MDCK cells

Farooq SM, Boppana NB, Devarajan A, Asokan D, Sekaran SD, Shankar EM, et al.

PLoS One, 2014;9(4):e93056.
PMID: 24691130 DOI: 10.1371/journal.pone.0093056

Oxalate toxicity is mediated through generation of reactive oxygen species (ROS) via a process that is partly dependent on mitochondrial dysfunction. Here, we investigated whether C-phycocyanin (CP) could protect against oxidative stress-mediated intracellular damage triggered by oxalate in MDCK cells. DCFDA, a fluorescence-based probe and hexanoyl-lysine adduct (HEL), an oxidative stress marker were used to investigate the effect of CP on oxalate-induced ROS production and membrane lipid peroxidation (LPO). The role of CP against oxalate-induced oxidative stress was studied by the evaluation of mitochondrial membrane potential by JC1 fluorescein staining, quantification of ATP synthesis and stress-induced MAP kinases (JNK/SAPK and ERK1/2). Our results revealed that oxalate-induced cells show markedly increased ROS levels and HEL protein expression that were significantly decreased following pre-treatment with CP. Further, JC1 staining showed that CP pre-treatment conferred significant protection from mitochondrial membrane permeability and increased ATP production in CP-treated cells than oxalate-alone-treated cells. In addition, CP treated cells significantly decreased the expression of phosphorylated JNK/SAPK and ERK1/2 as compared to oxalate-alone-treated cells. We concluded that CP could be used as a potential free radical-scavenging therapeutic strategy against oxidative stress-associated diseases including urolithiasis.
Fulltext The diagnostic sensitivity of dengue rapid test assays is significantly enhanced by using a combined antigen and antibody testing approach

Fry SR, Meyer M, Semple MG, Simmons CP, Sekaran SD, Huang JX, et al.

PLoS Negl Trop Dis, 2011 Jun;5(6):e1199.
PMID: 21713023 DOI: 10.1371/journal.pntd.0001199

BACKGROUND: Serological tests for IgM and IgG are routinely used in clinical laboratories for the rapid diagnosis of dengue and can differentiate between primary and secondary infections. Dengue virus non-structural protein 1 (NS1) has been identified as an early marker for acute dengue, and is typically present between days 1-9 post-onset of illness but following seroconversion it can be difficult to detect in serum.
AIMS: To evaluate the performance of a newly developed Panbio® Dengue Early Rapid test for NS1 and determine if it can improve diagnostic sensitivity when used in combination with a commercial IgM/IgG rapid test.
METHODOLOGY: The clinical performance of the Dengue Early Rapid was evaluated in a retrospective study in Vietnam with 198 acute laboratory-confirmed positive and 100 negative samples. The performance of the Dengue Early Rapid in combination with the IgM/IgG Rapid test was also evaluated in Malaysia with 263 laboratory-confirmed positive and 30 negative samples.
KEY RESULTS: In Vietnam the sensitivity and specificity of the test was 69.2% (95% CI: 62.8% to 75.6%) and 96% (95% CI: 92.2% to 99.8) respectively. In Malaysia the performance was similar with 68.9% sensitivity (95% CI: 61.8% to 76.1%) and 96.7% specificity (95% CI: 82.8% to 99.9%) compared to RT-PCR. Importantly, when the Dengue Early Rapid test was used in combination with the IgM/IgG test the sensitivity increased to 93.0%. When the two tests were compared at each day post-onset of illness there was clear differentiation between the antigen and antibody markers.
CONCLUSIONS: This study highlights that using dengue NS1 antigen detection in combination with anti-glycoprotein E IgM and IgG serology can significantly increase the sensitivity of acute dengue diagnosis and extends the possible window of detection to include very early acute samples and enhances the clinical utility of rapid immunochromatographic testing for dengue.
Fulltext The detection and characterization of pathogenic Leptospira and the use of OMPs as potential antigens and immunogens

Gebriel AM, Subramaniam G, Sekaran SD

Trop Biomed, 2006 Dec;23(2):194-207.
PMID: 17322822 MyJurnal

The detection of leptospires in patient blood in the first week of the disease using PCR provides an early diagnostic tool. PCR using two sets of primers (G1/G2 and B64-I/B64-II) tested with samples seeded with 23 leptospiral strains from pathogenic and non-pathogenic strains was able to amplify leptospiral DNA from pathogenic strains only. Of the 39 antibody negative samples collected from patients suspected for leptospirosis, only 1 sample (2.6%) was PCR positive. Using LSSP-PCR, the G2 primers allowed the characterization of Leptopira species to 10 different genetic signatures which may have epidemiological value in determining species involved in outbreaks. Leptospiral outer membrane proteins from three strains were purified and reacted against patients sera and gave rise to different profiles for pathogenic and non-pathogenic strains. Lymphocytes of mice injected with OMPs proliferated and released IFN(-3) when stimulated in vitro using Leptospira OMP as antigens. This suggests that an immune response could be established using leptospiral OMPs as a putative vaccine. OMPs were also used in a Dot-ELISA to detect antibodies against Leptospira pathogens in humans.
Fulltext Different domains of dengue research in Malaysia: A systematic review and meta-analysis of questionnaire-based studies

Guad RM, Wu YS, Aung YN, Sekaran SD, Wilke ABB, Low WY, et al.

Int J Environ Res Public Health, 2021 04 23;18(9).
PMID: 33922427 DOI: 10.3390/ijerph18094474

This review provided a systematic overview of the questionnaire-related dengue studies conducted in Malaysia and evaluated their reliability and validity used in the questionnaires. An extensive literature search was conducted using various electronic databases, including PubMed, EMBASE, Medline, and ScienceDirect. Systematic reviews and meta-analysis (PRISMA) were selected as the preferred item reporting method. Out of 88 identified dengue-related, 57 published from 2000 to April 2020 met the inclusion criteria and were included. Based on the meta-analysis, a poor mean score was obtained for knowledge (49%), attitude (44%), and preventive practice (55%). The study showed that the level of knowledge on cardinal signs and modes of transmission for dengue virus were highest among health care workers, followed by students (international and local) and lastly community residents. In treatment-seeking behaviours, only half of the respondents (50.8%) would send their child to the nearest health clinics or hospitals when a child became restless or lethargic. The acceptance rate for dengue vaccine, bacteria (Wolbachia), as a vector for dengue control and self-test diagnostic kit for dengue showed considerably high (88.4%, 70%, and 44.8%, respectively). Health belief model (HBM) constructs, such as perceived barriers, perceived severity, perceived susceptibility, self-efficacy, and perceived benefit influence prevention practices. Lastly, only 23 articles (40.3%) had piloted or pretested the questionnaire before surveying, in which three reported Cronbach's alpha coefficient (0.70-0.90). A need for active participation of communities and healthcare personnel, promotion of awareness, and safe complementary medicines, as well as assessment of psychometric properties of questionnaire use in dengue surveys in Malaysia, in order for assessing dengue reliably and valid.

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links