Displaying publications 1 - 20 of 47 in total

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  1. Fulltext Retrospective Analysis of Antibiotic Resistance in Streptococcus spp. from HIV Patients (2012-2017) from Southern India
    Swathirajan CR, Rameshkumar MR, Solomon SS, Vignesh R, Balakrishnan P
    Adv Biomed Res, 2019;8:1.
    PMID: 30775343 DOI: 10.4103/abr.abr_185_18
  2. Chronic hepatitis C virus infection triggers spontaneous differential expression of biosignatures associated with T cell exhaustion and apoptosis signaling in peripheral blood mononucleocytes
    Barathan M, Gopal K, Mohamed R, Ellegård R, Saeidi A, Vadivelu J, et al.
    Apoptosis, 2015 Apr;20(4):466-80.
    PMID: 25577277 DOI: 10.1007/s10495-014-1084-y
    Persistent hepatitis C virus (HCV) infection appears to trigger the onset of immune exhaustion to potentially assist viral persistence in the host, eventually leading to hepatocellular carcinoma. The role of HCV on the spontaneous expression of markers suggestive of immune exhaustion and spontaneous apoptosis in immune cells of chronic HCV (CHC) disease largely remain elusive. We investigated the peripheral blood mononuclear cells of CHC patients to determine the spontaneous recruitment of cellular reactive oxygen species (cROS), immunoregulatory and exhaustion markers relative to healthy controls. Using a commercial QuantiGenePlex(®) 2.0 assay, we determined the spontaneous expression profile of 80 different pro- and anti-apoptotic genes in persistent HCV disease. Onset of spontaneous apoptosis significantly correlated with the up-regulation of cROS, indoleamine 2,3-dioxygenase (IDO), cyclooxygenase-2/prostaglandin H synthase (COX-2/PGHS), Foxp3, Dtx1, Blimp1, Lag3 and Cd160. Besides, spontaneous differential surface protein expression suggestive of T cell inhibition viz., TRAIL, TIM-3, PD-1 and BTLA on CD4+ and CD8+ T cells, and CTLA-4 on CD4+ T cells was also evident. Increased up-regulation of Tnf, Tp73, Casp14, Tnfrsf11b, Bik and Birc8 was observed, whereas FasLG, Fas, Ripk2, Casp3, Dapk1, Tnfrsf21, and Cflar were moderately up-regulated in HCV-infected subjects. Our observation suggests the spontaneous onset of apoptosis signaling and T cell exhaustion in chronic HCV disease.
  3. Fulltext Evaluation of the severity and monitoring the progress of treatment of idiopathic congenital Talipes Equinovarus by Ponseti method
    Vignesh, R., Theingi, M.M., Soe, San, Ooi, P.C., Ma, Nwet
    Asian Journal of Medicine and Health Sciences, 2019;2(1):38-46.
    MyJurnal
    Introduction: Congenital talipes equinovarus (CTEV), commonly known as the ‘club foot’ is a developmental disorder of the lower limb that is related with socioeconomic difficulties. Ponseti method is considered as the most popular and successful method of treatment for CTEV children. This study was aimed to evaluate the severity and monitoring the progress of initial treatment of CTEV children.

    Materials and methods: Forty two patients with 58 idiopathic CTEV feet treated at a hospital outpatient clinic from January 2017 to February 2018 were included in the study. Ponseti method and Pirani score system were used and the results were calculated after wearing brace for three months duration at the end of serial casting.

    Results: The patients in the study were in the age range of 14 days to 12 months. The mean number of changing of casting was 7.2 times. Casts were changed 1.9 times more in the severe cases than mild cases. Thirty six (85.7%) cases needed percutaneous tenotomy. There was no need to perform tenotomy for the mild cases. The initial achievement rate was 90.5 % and there were 9.5 % relapsed cases because of incorrect wearing of the brace. Statistically significant score differences were seen before and after treatment (P-value
  4. Isolation and genotyping of Toxoplasma gondii from free-range ducks in Malaysia
    Puvanesuaran VR, Noordin R, Balakrishnan V
    Avian Dis, 2013 Mar;57(1):128-32.
    PMID: 23678741
    Toxoplasma gondii is a parasitic protozoan that infects nearly one-third of humans. The present study was performed to isolate and genotype T. gondii from free-range ducks in Malaysia. Sera, heads, and hearts from 205 ducks were obtained from four states in Peninsular Malaysia, and 30 (14.63%) sera were found to be seropositive when assayed with the modified agglutination test (MAT > or = 1:6). All the positive samples were inoculated into mice, and T. gondii was successfully isolated from four individual duck samples (1.95%), which were initially found to be strongly seropositive (MAT > or = 1:24). The isolates were subjected to PCR-RFLP analysis, and two T. gondii strains were identified: type I and type II. This is the first reported study on the genetic characterization of T. gondii isolates from free-range farm animals in Southeast Asia.
  5. CD8+ T cells of chronic HCV-infected patients express multiple negative immune checkpoints following stimulation with HCV peptides
    Barathan M, Mohamed R, Vadivelu J, Chang LY, Vignesh R, Krishnan J, et al.
    Cell Immunol, 2017 03;313:1-9.
    PMID: 28104239 DOI: 10.1016/j.cellimm.2016.12.002
    Hepatitis C virus (HCV)-specific CD4+ and CD8+ T cells are key to successful viral clearance in HCV disease. Accumulation of exhausted HCV-specific T cells during chronic infection results in considerable loss of protective functional immune responses. The role of T-cell exhaustion in chronic HCV disease remains poorly understood. Here, we studied the frequency of HCV peptide-stimulated T cells expressing negative immune checkpoints (PD-1, CTLA-4, TRAIL, TIM-3 and BTLA) by flow cytometry, and measured the levels of Th1/Th2/Th17 cytokines secreted by T cells by a commercial Multi-Analyte ELISArray™ following in vitro stimulation of T cells using HCV peptides and phytohemagglutinin (PHA). HCV peptide-stimulated CD4+ and CD8+ T cells of chronic HCV (CHC) patients showed significant increase of CTLA-4. Furthermore, HCV peptide-stimulated CD4+ T cells of CHC patients also displayed relatively higher levels of PD-1 and TRAIL, whereas TIM-3 was up-regulated on HCV peptide-stimulated CD8+ T cells. Whereas the levels of IL-10 and TGF-β1 were significantly increased, the levels of pro-inflammatory cytokines IL-2, TNF-α, IL-17A and IL-6 were markedly decreased in the T cell cultures of CHC patients. Chronic HCV infection results in functional exhaustion of CD4+ and CD8+ T cells likely contributing to viral persistence.
  6. HIV-specific T-cell Responses and Generalized Activation in HIV-1 Infected Long-term Non-progressors and Progressors from South India
    Swathirajan CR, Vignesh R, Waldrop G, Shanmugasundaram U, Nandagopal P, Solomon SS, et al.
    Curr. HIV Res., 2018;16(4):302-314.
    PMID: 30543175 DOI: 10.2174/1570162X17666181212122607
    BACKGROUND: Anti-viral cytokine expressions by cytotoxic T-cells and lower activation rates have been reported to correlate with suppressed HIV replication in long-term non-progressors (LTNP). Immune mechanisms underlying disease non-progression in LTNP might vary with HIV-1 subtype and geographical locations.

    OBJECTIVE: This study evaluates cytokine expression and T-cells activation in relation to disease non-progression in LTNP.

    METHODS: HIV-1 Subtype C infected LTNP (n=20) and progressors (n=15) were enrolled and flowcytometry assays were performed to study HIV-specific CD8 T-cells expressing IL-2, IFN-γ, TNF-α and MIP-1β against gag and env peptides. CD4+ T-cell activation was evaluated by surface expression of HLADR and CD38.

    RESULTS: Proportions of cytokines studied did not differ significantly between LTNP and progressors, while contrasting correlations with disease progression markers were observed in LTNP. CD4+ T-cell activation rates were significantly lower in LTNP compared to progressors which indicate the potential role of T-cell activation rates in disease non-progression in LTNP.

    CONCLUSION: LTNP and progressors showed similar CD8+ T-cell responses, but final conclusions can be drawn only by comparing multiple immune factors in larger LTNP cohort with HIV-1 infected individuals at various levels of disease progression. A possible role of HIV-1 subtype variation and ethnic differences in addition to host-genetic and viral factors cannot be ruled out.

  7. Fulltext Thalidomide as a Potential HIV Latency Reversal Agent: Is It the Right Time to Forget the Ancestral Sins?
    Vignesh R, Shankar EM
    EBioMedicine, 2017 Oct;24:20-21.
    PMID: 28865747 DOI: 10.1016/j.ebiom.2017.08.025
  8. Fulltext Could Nutraceutical Approaches Possibly Attenuate the Cytokine Storm in COVID-19 Patients?
    Vignesh R, Velu V, Sureban SM
    Front Cell Infect Microbiol, 2021;11:667733.
    PMID: 33968808 DOI: 10.3389/fcimb.2021.667733
  9. Fulltext Assessing the potential of NS2B/NS3 protease inhibitors biomarker in curbing dengue virus infections: In silico vs. In vitro approach
    Norshidah H, Leow CH, Ezleen KE, Wahab HA, Vignesh R, Rasul A, et al.
    Front Cell Infect Microbiol, 2023;13:1061937.
    PMID: 36864886 DOI: 10.3389/fcimb.2023.1061937
    An increase in the occurrence of viral infectious diseases is a global concern for human health. According to a WHO report, dengue virus (DENV) is one of the most common viral diseases affecting approximately 400 million people annually, with worsening symptoms in nearly 1% of cases. Both academic and industrial researchers have conducted numerous studies on viral epidemiology, virus structure and function, source and route of infection, treatment targets, vaccines, and drugs. The development of CYD-TDV or Dengvaxia® vaccine has been a major milestone in dengue treatment. However, evidence has shown that vaccines have some drawbacks and limitations. Therefore, researchers are developing dengue antivirals to curb infections. DENV NS2B/NS3 protease is a DENV enzyme essential for replication and virus assembly, making it an interesting antiviral target. For faster hit and lead recognition of DENV targets, methods to screen large number of molecules at lower costs are essential. Similarly, an integrated and multidisciplinary approach involving in silico screening and confirmation of biological activity is required. In this review, we discuss recent strategies for searching for novel DENV NS2B/NS3 protease inhibitors from the in silico and in vitro perspectives, either by applying one of the approaches or by integrating both. Therefore, we hope that our review will encourage researchers to integrate the best strategies and encourage further developments in this area.
  10. Fulltext SARS-CoV-2 in Pregnant Women: Consequences of Vertical Transmission
    Chaubey I, Vignesh R, Babu H, Wagoner I, Govindaraj S, Velu V
    Front Cell Infect Microbiol, 2021;11:717104.
    PMID: 34568094 DOI: 10.3389/fcimb.2021.717104
  11. Fulltext Is Herd Immunity Against SARS-CoV-2 a Silver Lining?
    Vignesh R, Shankar EM, Velu V, Thyagarajan SP
    Front Immunol, 2020;11:586781.
    PMID: 33101320 DOI: 10.3389/fimmu.2020.586781
  12. Fulltext Hyper-Expression of PD-1 Is Associated with the Levels of Exhausted and Dysfunctional Phenotypes of Circulating CD161++TCR iVα7.2+ Mucosal-Associated Invariant T Cells in Chronic Hepatitis B Virus Infection
    Yong YK, Saeidi A, Tan HY, Rosmawati M, Enström PF, Batran RA, et al.
    Front Immunol, 2018;9:472.
    PMID: 29616020 DOI: 10.3389/fimmu.2018.00472
    Mucosal-associated invariant T (MAIT) cells, defined as CD161++TCR iVα7.2+ T cells, play an important role in the innate defense against bacterial infections, and their functionality is impaired in chronic viral infections. Here, we investigated the frequency and functional role of MAIT cells in chronic hepatitis B virus (HBV) infection. The peripheral CD3+CD161++TCR iVα7.2+ MAIT cells in chronic HBV-infected patients and healthy controls were phenotypically characterized based on CD57, PD-1, TIM-3, and CTLA-4, as well as HLA-DR and CD38 expression. The frequency of MAIT cells was significantly decreased among chronic HBV-infected individuals as compared to controls. Expression of CD57, PD-1, CTLA-4, as well as HLA-DR and CD38 on MAIT cells was significantly elevated in chronic HBV-infected individuals relative to controls. The percentage of T cell receptor (TCR) iVα7.2+ CD161+ MAIT cells did not correlate with HBV viral load but inversely with HLA-DR on CD4+ T cells and MAIT cells and with CD57 on CD8+ T cells suggesting that decrease of MAIT cells may not be attributed to direct infection by HBV but driven by HBV-induced chronic immune activation. The percentage and expression levels of PD-1 as well as CTLA-4 on MAIT cells inversely correlated with plasma HBV-DNA levels, which may suggest either a role for MAIT cells in the control of HBV infection or the effect of HBV replication in the liver on MAIT cell phenotype. We report that decrease of TCR iVα7.2+ MAIT cells in the peripheral blood and their functions were seemingly impaired in chronic HBV-infected patients likely because of the increased expression of PD-1.
  13. Fulltext Dengue Infection - Recent Advances in Disease Pathogenesis in the Era of COVID-19
    Yong YK, Wong WF, Vignesh R, Chattopadhyay I, Velu V, Tan HY, et al.
    Front Immunol, 2022;13:889196.
    PMID: 35874775 DOI: 10.3389/fimmu.2022.889196
    The dynamics of host-virus interactions, and impairment of the host's immune surveillance by dengue virus (DENV) serotypes largely remain ambiguous. Several experimental and preclinical studies have demonstrated how the virus brings about severe disease by activating immune cells and other key elements of the inflammatory cascade. Plasmablasts are activated during primary and secondary infections, and play a determinative role in severe dengue. The cross-reactivity of DENV immune responses with other flaviviruses can have implications both for cross-protection and severity of disease. The consequences of a cross-reactivity between DENV and anti-SARS-CoV-2 responses are highly relevant in endemic areas. Here, we review the latest progress in the understanding of dengue immunopathogenesis and provide suggestions to the development of target strategies against dengue.
  14. Fulltext Could Perturbation of Gut Microbiota Possibly Exacerbate the Severity of COVID-19 via Cytokine Storm?
    Vignesh R, Swathirajan CR, Tun ZH, Rameshkumar MR, Solomon SS, Balakrishnan P
    Front Immunol, 2020;11:607734.
    PMID: 33569053 DOI: 10.3389/fimmu.2020.607734
  15. Fulltext Immune Biomarkers for Diagnosis and Treatment Monitoring of Tuberculosis: Current Developments and Future Prospects
    Yong YK, Tan HY, Saeidi A, Wong WF, Vignesh R, Velu V, et al.
    Front Microbiol, 2019;10:2789.
    PMID: 31921004 DOI: 10.3389/fmicb.2019.02789
    Tuberculosis (TB) treatment monitoring is paramount to clinical decision-making and the host biomarkers appears to play a significant role. The currently available diagnostic technology for TB detection is inadequate. Although GeneXpert detects total DNA present in the sample regardless live or dead bacilli present in clinical samples, all the commercial tests available thus far have low sensitivity. Humoral responses against Mycobacterium tuberculosis (Mtb) antigens are generally low, which precludes the use of serological tests for TB diagnosis, prognosis, and treatment monitoring. Mtb-specific CD4+ T cells correlate with Mtb antigen/bacilli burden and hence might serve as good biomarkers for monitoring treatment progress. Omics-based techniques are capable of providing a more holistic picture for disease mechanisms and are more accurate in predicting TB disease outcomes. The current review aims to discuss some of the recent advances on TB biomarkers, particularly host biomarkers that have the potential to diagnose and differentiate active TB and LTBI as well as their use in disease prognosis and treatment monitoring.
  16. Could rapid test reader maximize the benefits to the HIV self-tester?
    Balakrishnan P, Girija ASS, Kannan I, Vignesh R, Shankar EM, Sucharitha ST
    Indian J Med Microbiol, 2023;43:49-50.
    PMID: 36280566 DOI: 10.1016/j.ijmmb.2022.10.004
  17. Fulltext Occurrence of enteric parasitic infections among HIV-infected individuals and its relation to CD4 T-cell counts with a special emphasis on coccidian parasites at a tertiary care centre in South India
    Swathirajan CR, Vignesh R, Pradeep A, Solomon SS, Solomon S, Balakrishnan P
    Indian J Med Microbiol, 2017 Jan-Mar;35(1):37-40.
    PMID: 28303816 DOI: 10.4103/ijmm.IJMM_16_164
    CONTEXT: Diarrhoea is one of the major complications occurring in over 90% of HIV-infected individuals in developing countries. Coccidian group of parasites, being opportunistic pathogens, have been implicated as the most common causative agents of diarrhoea among HIV-infected population.

    AIMS: The aim was to study the magnitude of parasitic diarrhoea with special context to coccidian parasitic infections in HIV-infected individuals and their association with the patient's immunological status measured by CD4 T-cell counts.

    SETTINGS AND DESIGN: This investigation was performed between January 2002 and December 2014 at a tertiary HIV care centre in Chennai, South India.

    MATERIALS AND METHODS: Stool samples were collected and microscopically observed for parasites using direct, formal-ether-concentrated wet mounts and modified acid-fast staining for coccidian parasites. CD4 T-cell counts were done by FACScount.

    STATISTICAL ANALYSIS USED: All statistical analyses were performed using GraphPad Prism software, version 5.0, andP < 0.05 was considered statistically significant.

    RESULTS: Coccidian parasitic infection accounted for about 23.4% of parasitic infections, and of these, Cystoisospora belli was observed to be the most common cause of diarrhoea (88.8%), followed by Cryptosporidium spp. (9.9%) and Cyclospora spp. (1.3%). Trend analysis of coccidian aetiology during the study period revealed a significant rise in the positivity of C. belli and Cryptosporidium spp. (P = 0.001). Among the HIV patients with CD4+ T-cell counts <200 cells/μL, Cryptosporidium infection was most common (90%), followed by infection with C. belli(61.4%).

    CONCLUSIONS: Coccidian parasites continue to be the most common aetiological agent of diarrhoea among patients with HIV. The increasing trend of positivity of both cystoisosporiasis and cryptosporidiosis over the study period and the high positivity of cryptosporidiosis in patients with lower CD4+ T-cell counts are issues of serious concern. The findings call for the need for the early diagnosis of coccidian parasites and appropriate intervention among HIV-infected patients.
  18. Fulltext Risk factors and frequency of tuberculosis-associated immune reconstitution inflammatory syndrome among HIV/Tuberculosis co-infected patients in Southern India
    Vignesh R, Swathirajan CR, Solomon SS, Shankar EM, Murugavel KG
    Indian J Med Microbiol, 2017 Apr-Jun;35(2):279-281.
    PMID: 28681821 DOI: 10.4103/ijmm.IJMM_16_163
    Immune reconstitution inflammatory syndrome (IRIS) continues to be a complication in HIV/tuberculosis (TB) co-infected patients initiating highly active antiretroviral therapy (HAART). The aim of this study was to evaluate the risk factors associated with developing IRIS to identify a possible biomarker to predict or diagnose IRIS in patients initiating HAART. A total of 175 HIV/TB co-infected patients initiating HAART were followed up longitudinally during September 2010 to May 2013 attending a HIV care clinic in Chennai. Patients were followed up longitudinally after HAART initiation and baseline demographic, laboratory parameters and treatment characteristics between patients with IRIS events and those without IRIS events were compared. Chi-square or Fisher's exact test for categorical variables and a Wilcoxon rank-sum test for continuous variables were performed using SPSS, version 12.0 software. Patients with IRIS had a significantly lower median baseline CD4+ T-cell count (P = 0.0039). There were no differences in terms of sex, CD4 T-cell %, plasma viral load, time interval between initiating ATT and HAART between the IRIS and non-IRIS patients. Low CD4+ T-cell count (<100 cells/μL) could be used as a marker to screen and monitor patients initiating HAART.
  19. Fulltext Infectious risk assessment of unsafe handling practices and management of clinical solid waste
    Hossain MS, Rahman NN, Balakrishnan V, Puvanesuaran VR, Sarker MZ, Kadir MO
    Int J Environ Res Public Health, 2013 Jan 31;10(2):556-67.
    PMID: 23435587 DOI: 10.3390/ijerph10020556
    The present study was undertaken to determine the bacterial agents present in various clinical solid wastes, general waste and clinical sharp waste. The waste was collected from different wards/units in a healthcare facility in Penang Island, Malaysia. The presence of bacterial agents in clinical and general waste was determined using the conventional bacteria identification methods. Several pathogenic bacteria including opportunistic bacterial agent such as Pseudomonas aeruginosa, Salmonella spp., Klebsiella pneumoniae, Serratia marcescens, Acinetobacter baumannii, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus pyogenes were detected in clinical solid wastes. The presence of specific pathogenic bacterial strains in clinical sharp waste was determined using 16s rDNA analysis. In this study, several nosocomial pathogenic bacteria strains of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Lysinibacillus sphaericus, Serratia marcescens, and Staphylococcus aureus were detected in clinical sharp waste. The present study suggests that waste generated from healthcare facilities should be sterilized at the point of generation in order to eliminate nosocomial infections from the general waste or either of the clinical wastes.
  20. Fulltext The Implementation of HIV Self-Testing in Resource-Limited Settings Where the HIV Disease Burden is High
    Balakrishnan P, Smiline Girija AS, Shanmugam S, Kannan I, Vignesh R, Shankar EM, et al.
    Int J Public Health, 2023;68:1605790.
    PMID: 37266035 DOI: 10.3389/ijph.2023.1605790
    In resource-limited settings, there is growing evidence that HIV testing is lacking among high-risk key populations such as men having sex with men, injection drug users, and transgenders largely due to stigma, discrimination, and lack of confidentiality. Findings from recent studies among high-risk key populations and the general population from various regions including resource-limited settings support the need for wider accessibility of HIV self-testing (HIV-ST) to reach those who may not otherwise have access to testing. Therefore, HIV-ST has untapped potential as a strategy to improve access to HIV testing and to increase testing frequency among key high-risk populations and their partners. Though HIV-ST has emerged as a safe, acceptable, and effective way to reach people, there are several roadblocks to implementing the HIV-ST policy, and fast-track policy implementation needs to be necessitated with newer or modified strategic plans.
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