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Biomedical subjects

Pachamuthu Balakrishnan

Publications and source records attributed to Pachamuthu Balakrishnan.

15 recordsLinked to original sources
PubMed2006

Effective evaluation of novel low-cost CD4 monitoring assays.

Indian generic pharmaceutical manufacturers have dramatically reduced the price of antiretroviral therapy thus improving access, but monitoring costs of the patients on therapy remain high. Few low-cost monitoring assays are available and validation against gold standard is exceedingly important before implementation. Validity is defined as the degree to which the results of the new technique correspond to the true state of the phenomena being measured by the gold standard. Majority of publications report validation of low-cost CD4 assay using correlation coefficient, which is the best measure of association, and a few publications report intra-class correlation coefficient, which is a measure of reliability. However, Bland-Altman analysis that directly quantifies the difference seen between the novel low-cost CD4 assay and the gold standard is the most ideal approach. Absolute CD4 counts estimated for samples collected from 110 HIV+ and 118 HIV- individuals using novel EasyCD4 assay and the gold standard FACSCount assay were validated using correlation coefficient, intra-class correlation coefficient and Bland Altman analysis. The results from these different analyses have been compared and the significance of each has been explained. Hence, to validate a low-cost assay Bland-Altman analysis and plot is recommended.

Antiretroviral Therapy, Highly Active↗
PubMed2006

Detection of pulmonary Mycoplasma pneumoniae infections in HIV-infected subjects using culture and serology.

OBJECTIVE: The true prevalence of Mycoplasma pneumoniae infections involving the respiratory tracts of HIV-infected individuals is still unclear. This study examined the prevalence of M. pneumoniae in 100 HIV-infected individuals at an AIDS care center in Chennai, India, using conventional laboratory techniques and interpretation criteria. METHODS: Diagnosis was based on culture, cold agglutination test, and commercial enzyme-linked immunosorbent assay (ELISA) for the qualitative determination of IgM antibodies against M. pneumoniae. The efficacies of the different diagnostic procedures used in the study were analyzed. RESULTS: The prevalence of M. pneumoniae was 31% by culture and 21% by IgM ELISA. Cough (p=0.03, OR 3.8, 95% CI 1-17.8), myalgia (p=0.04, OR 2.5, 95% CI 1-6.6), rales (p=0.04, OR 2.4, 95% CI 1-6.6), and cervical adenopathy (p=0.03, OR 2.7, 95% CI 1-7.1) were the symptoms that significantly corroborated culture positivity. Patients positive for M. pneumoniae by culture or IgM antibody had significantly greater CD4+ T-cell depletion and anemia than those without any evidence of infection. CONCLUSIONS: This study provides the means to diagnose M. pneumoniae infection and information on the prevalence of the pathogen in HIV-infected individuals in resource constrained settings. Although modern molecular techniques may provide more insight into the prevalence of M. pneumoniae in HIV-infected individuals, conventional methods can still be used in diagnosis.

AIDS-Related Opportunistic Infections↗
PubMed2006

Serosurveillance of acute Mycoplasma pneumoniae infection among HIV infected patients with pulmonary complaints in Chennai, Southern India.

BACKGROUND: The true seroepidemiology of acute Mycoplasma pneumoniae infection in HIV infected individuals is ambiguous. METHODS: This study examined the serosurveillance of IgM antibodies to M. pneumoniae in HIV infected patients presenting with pulmonary symptoms at a tertiary AIDS care center in Chennai, Southern India, using cold-haemagglutination test and commercial enzyme linked immunosorbent assay in acute serum specimens. RESULTS: One hundred HIV infected patients had enrolled in the study; 21 (21%) were positive for M. pneumoniae IgM antibodies by ELISA and 34 (34%) showed evidence of cold hemagglutinins. CONCLUSION: This serosurveillance study reports a 21% prevalence of M. pneumoniae IgM antibody among HIV infected patients with pulmonary symptoms by ELISA and non-specific diagnosis was confirmed in 34% of the cases screened. Determination of cold agglutination titer could be used as a substitute to other expensive procedures in limited resource settings and third-world nations to diagnose M. pneumoniae infections for prompt initiation of therapy, as CAT has been found to be 100% sensitive and 84% specific in the diagnosis of M. pneumoniae infection.

AIDS-Related Opportunistic Infections↗
PubMed2006

Reasons for modification of generic highly active antiretroviral therapeutic regimens among patients in southern India.

OBJECTIVE: To describe reasons for modification and discontinuation of antiretroviral regimens in association with adverse events (AEs), treatment failure, and cost among patients in southern India. METHODS: Secular trends of patients initiating highly active antiretroviral therapy (HAART) between January 1996 and October 2004 at a tertiary HIV referral center in India were analyzed using a previously validated natural history database. RESULTS: All previously antiretroviral therapy-naive patients who initiated HAART (N = 1443) and had at least 1 follow-up visit were evaluated. The median CD4 count at the time of initiating HAART was 108 cells/microL. The most common first-line regimens were stavudine (d4T) plus lamivudine (3TC) plus nevirapine (NVP) (63%), zidovudine (AZT) plus 3TC plus NVP (19%), d4T plus 3TC plus efavirenz (EFV) (9%), and AZT plus 3TC plus EFV (4%). Twenty percent of patients modified their first-line regimen. The most common reason for modifying therapy was the development of an AE (64%), followed by cost (19%) and treatment failure (14%), with median times to modify therapy being 40, 151, and 406 days, respectively. Common AEs were itching and/or skin rash (66%), hepatotoxicity (27%), and anemia (23%). Nine percent of patients discontinued therapy entirely after a median duration of 124 days, primarily because of cost (64%). CONCLUSION: The most common reason for modifying therapy was the occurrence of AEs, whereas cost was the most common reason for discontinuing therapy. Despite increasing access to lower cost generic HAART in India, even less expensive and more tolerable first-line regimens and cost-effective treatment monitoring tools need to be introduced to achieve better treatment outcomes and access in resource-constrained settings.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Bacterial vaginosis in women of low socioeconomic status living in slum areas in Chennai, India.

Bacterial vaginosis (BV) is a common cause of vaginitis among women of childbearing age. This study was performed to investigate the prevalence of BV and its association with sexually transmitted infections among 487 women of low socioeconomic status. Blood, vaginal and endocervical swabs were tested for HIV, herpes simplex virus-2 (HSV-2), Treponema pallidum, BV, Chlamydia trachomatis, Neisseria gonorrhoea and Trichomonas vaginalis. Of the women screened for BV, 120 (25, 95% CI 20.8-28.4) were positive and 40 (8.2, 95% CI 5.8-10.6) were intermediate. Bacterial vaginosis was significantly associated with age >25 (P = 0.014) and sexual experience (P = 0.085). Bacterial vaginosis was also related to concurrent infections with T. vaginalis (relative risk (RR) = 6.6, 95% CI 2.8-15.5, P = 0.000) and HSV-2 (RR = 2, 95% CI 1.3-2.9; P = 0.0031). The role of other possible risk factors needs to be explored.

Adolescent↗
PubMed2006

A reliable and inexpensive EasyCD4 assay for monitoring HIV-infected individuals in resource-limited settings.

Serial measurements of absolute CD4+ T-lymphocyte counts are required to initiate and gauge response to therapy and monitor disease progression. Hence, there is an urgent need to evaluate the accuracy and validity of low-cost CD4+ T-cell count assays. Tripotassium EDTA blood specimens from HIV-infected individuals were studied using a novel flow cytometric assay (EasyCD4 assay; Guava Technologies, Hayward, CA) in comparison with standard flow cytometry (FACSCount; Becton Dickinson Immunocytometry Systems, San Jose, CA). The sensitivity, specificity value by EasyCD4 assay in enumerating absolute CD4+ T-cell counts of less than 200 cells/microL were 95% and 100%, respectively. Bland-Altman analysis showed close agreement, with the EasyCD4 assay yielding CD4+ T-cell counts a mean difference of -26 cells/microL (95% confidence interval, -96 to 44 cells/microL) higher than by flow cytometry. Our data suggest that EasyCD4 assay could be a useful alternative assay to conventional flow cytometry, may be appropriate for use in resource-limited settings.

Adolescent↗
PubMed2006

Seroprevalence of Mycoplasma pneumoniae in HIV-infected patients using a microparticle agglutination test.

Mycoplasma pneumoniae is increasingly recognized as a common and important pathogen in community settings, and is responsible for various pulmonary and extrapulmonary conditions in the normal population. However, the seroepidemiology of acute M. pneumoniae infection in HIV-infected individuals is still unclear worldwide. This study examined the seroprevalence of antibodies to M. pneumoniae in HIV-infected patients admitted with respiratory complaints at a tertiary AIDS care centre in Chennai, India. A commercial gelatin microparticle agglutination test (Serodia-Myco II, Fujirebio) was used for the determination of antibodies against M. pneumoniae in acute serum specimens. Of the 200 HIV-infected patients with underlying pulmonary conditions tested, 34 (17 % positivity; 95 % CI 12-23 %) had antibodies specific to M. pneumoniae, while among the 40 patients with no underlying pulmonary symptoms, five (12.5 % positivity; 95 % CI 4-27 %) had evidence of anti-M. pneumoniae antibody. This shows that the incidence of M. pneumoniae seropositivity is greater in patients with underlying pulmonary complaints. Most positive titres were found in the age group 28-37 years in the symptomatic and symptom-free groups (64.7 and 60 %, respectively). The positive titres ranged from 40 to >20 480. High titres (> or =320) were found in 10 out of the 39 patients (25.6 %). This seroprevalence study reports a 16.2 % prevalence of M. pneumoniae infections in HIV-infected patients by a particle agglutination test.

AIDS-Related Opportunistic Infections↗
PubMed2005

Rapid viral load suppression following generic highly active antiretroviral therapy in Southern Indian HIV-infected patients.

We prospectively studied the initial results of 6 months of generic efavirenz-based therapy on the plasma viral load in 40 patients at YRG Centre for AIDS Research and Education, a tertiary HIV referral centre in southern India. The median baseline plasma viral load was 259,000 copies/ml and at 6 months 95% of patients had plasma viral loads less than 400 copies/ml. The data support the use of generic non-nucleoside reverse transcriptase inhibitor-based regimens in resource-limited settings.

Adult↗
PubMed2005

Bacterial vaginosis in female sex workers in Chennai, India.

Bacterial vaginosis (BV) causes obstetric and gynaecological complications and non-chlamydial/non-gonococcal pelvic inflammatory disease and has been shown to be associated with the risk of acquiring HIV and herpes simplex (HSV)-2 infections. This study investigated both the prevalence of BV and its association with STDs among 582 female sex workers living in Chennai, South India. Blood, vaginal and endocervical swabs were tested for HSV-2, HIV, Treponema pallidum, BV, Chlamydia trachomatis, Neisseria gonorrhoea and Trichomonas vaginalis. The vaginal swabs collected were Gram's stained and analysed for BV by Nugent's scoring criteria. Of the women studied, 45% (95% CI, 40.6-48.7) were positive, 39.5% (95% CI, 35.5-43.5) were negative and 16% (95% CI, 12.8-18.7) were intermediate for BV. Bacterial vaginosis positivity was directly related to concurrent infection with HSV-2 (RR 1.3, AR 12, P = 0.00), T vaginalis (RR 1.5, AR 10, P = 0.01) T. pallidum (RR 2.8, AR 16, P = 0.00) and HIV (RR 4.1, AR 52, P = 0.01). Future studies are needed to focus on the risk factors for BV.

Adult↗
PubMed2005

HIV type 1 genotypic variation in an antiretroviral treatment-naive population in southern India.

Most studies of HIV-1 drug resistance have examined subtype B viruses; fewer data are available from developing countries, where non-B subtypes predominate. We determined the prevalence of mutations at protease and reverse transcriptase drug resistance positions in antiretroviral drug-naive individuals in southern India. The pol region of the genome was amplified from plasma HIV-1 RNA in 50 patients. All sequences clustered with HIV-1 subtype C. All patients had at least one protease and/or RT mutation at a known subtype B drug resistance position. Twenty percent of patients had mutations at major protease inhibitor resistance positions and 100% had mutations at minor protease inhibitor resistance positions. Six percent and 14% of patients had mutations at nucleoside reverse transcriptase inhibitor and/or nonnucleoside reverse transcriptase inhibitor resistance positions, respectively. Larger scale studies need to be undertaken to better define the genotypic variation of circulating Indian subtype C viruses and their potential impact on drug susceptibility and clinical outcome in treated individuals.

Adult↗
PubMed2005

Low-cost monitoring of HIV infected individuals on highly active antiretroviral therapy (HAART) in developing countries.

The standard methods to monitor HIV infection are flow cytometry-based for CD4+ T lymphocyte count and molecular assays to quantify plasma viral load of HIV. Few laboratories in resource-limited countries can run these tests as a majority of the HIV infected individuals are poor. A number of currently available low-cost assays which require less expensive equipment and reagents, may be well-suited to such countries. These include manual and ELISA based CD4 cell assays, and ultrasensitive reverse transcriptase quantitation (Cavidi) and p24 (ELAST) assays to monitor virus load. But better internal quality assurance and quality control (QA/QC) programmes are essential. This review discusses the low-cost assays and their role in clinical monitoring of HIV infected individuals in resource-limited countries like as India.

Antiretroviral Therapy, Highly Active↗
PubMed2004

Incidence of immune reconstitution syndrome in HIV/tuberculosis-coinfected patients after initiation of generic antiretroviral therapy in India.

This paper describes the incidence of immune reconstitution syndrome (IRS) from the developing world and implications for clinicians. Eleven of 144 HIV and tuberculosis (TB)-coinfected individuals followed for 72 person-years developed IRS within 6 months of initiating generic highly active antiretroviral therapy (HAART). All of the IRS patients were male, with a median age of 29 years; median CD4 at HAART initiation was 123 cells/mm3, and 6-month median CD4 rise was 124 cells/mm3. There was no statistical difference in CD4 rise or CD4 count and duration of TB treatment at HAART initiation between those who did and those who did not develop IRS (P = 0.8380). The median time to development of clinical IRS was 42 days (range 10-89 days). The incidence of IRS in this cohort is 15.2 cases per 100 patient-years. With increased coprevalence of opportunistic infections, especially TB, and increasing access to antiretroviral therapy in the developing world, clinicians in these countries must be able to identify IRS and relieve symptoms without compromising clinical care.

AIDS-Related Opportunistic Infections↗
PubMed2004

An inexpensive, simple, and manual method of CD4 T-cell quantitation in HIV-infected individuals for use in developing countries.

CD4+ T lymphocytes are currently the most common surrogate marker indicating immune status and disease progression with HIV infection. The cost of monitoring disease progression and response to therapy is still prohibitively expensive. Flow cytometry is the gold standard for the estimation of CD4+, but the high initial investment for this technology and expensive reagents makes it unaffordable for developing countries like India. We evaluated the Coulter cytosphere assay for quantifying CD4+ T lymphocytes in comparison with the standard method, flow cytometry, in 122 HIV-infected individuals. The correlation coefficient of the cytosphere assay compared with that of flow cytometry for CD4+ T lymphocytes was 0.97 (P< 0.0001), with a confidence interval of 0.95 to 0.98. The sensitivity, specificity, positive predictive value, and negative predictive value of the cytosphere assay in enumerating absolute CD4+ T-lymphocyte counts of less than 200/microL were 94.9%, 96.4%, 92.5%, and 97.6%, respectively. This is a simple inexpensive method and has a strong correlation with flow cytometry. Hence, the cytosphere assay can be an alternate to flow cytometry for the estimation of CD4+ T-lymphocyte counts, especially in resource-poor settings of developing countries, for monitoring HIV progression and response to therapy.

CD4 Lymphocyte Count↗