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Biomedical subjects

V Ravi

Publications and source records attributed to V Ravi.

At least 19 recordsLinked to original sources
PubMed2007

HPA axis activity and neuropathogenesis in HIV-1 clade C infection.

A disturbance in the activity of the hypothalamic-pituitary-adrenal (HPA) axis has been reported among individuals with HIV-1 infection. However, these studies have been carried out in the West where the infecting clade is clade B. HIV-1 infection is rapidly spreading in various parts of South East Asia, including India, where the HIV-1 infecting clade is largely clade C. An investigation of HPA axis activity in this type of infection is warranted since there are many structural differences between clades B and C. This study was carried out to investigate whether HIV-1 infection clade C interferes with the functions of the hippocampus and thereby affects the HPA axis. We tested the hypothesis that when hippocampus activity is disturbed, it leads to the development of neuropathogenesis in HIV-1 C-clade infected individuals. This study included asymptomatic HIV-1 seropositive individuals (n=117) and, age-matched, HIV-1 seronegative controls (n=29). Neuroendocrine function of the HPA axis was evaluated using plasma levels of cortisol, ACTH, and DHEA-S, both in the morning (0800-1000 hr) and evening (2000-2200 hr). A significant elevation of cortisol levels during A.M. and P.M. hours was observed in HIV-1 infected individuals when compared to the controls. Interestingly, no significant change in ACTH level was observed in HIV-1 seropositive subjects, either during A.M or P.M. Elevated levels of cortisol in HIV-1 seropositive subjects appear to be independent of ACTH and may be the result of a defective negative feedback mechanism. On the other hand, a significant decrease in the plasma levels of DHEA-S was observed during A.M. and P.M. hours in HIV-1 infected individuals, leading to an increased cortisol to DHEA-S ratio. Since increased levels of cortisol and decreased levels of DHEA-S are related to the development of neuropathogenesis, it is hypothesized that a study of the development of neurocognitive deficits among HIV-1 seropositive individuals in India is warranted.

Adolescent↗
PubMed2007

Prevalence of HIV, Hepatitis B, syphilis, and chlamydia among adults seeking treatment for a mental disorder in southern India.

This study estimated the prevalence, and identified the correlates, of HIV, chlamydia, syphilis, and Hepatitis B among patients seeking treatment for a mental disorder in India. Patients (n = 948) submitted a blood sample for serologic testing and participated in a brief interview. Lifetime prevalence rates were nearly 2% for HIV, 10% for chlamydia, 3% for Hepatitis B, and 3% for syphilis; 15% of patients had evidence of at least one infection. Bivariate associations between infection status and patient characteristics, including age, gender, psychiatric diagnosis, did not reveal any consistent risk profile. Instead, behavioral characteristics (i.e., multiple partners, exchanging sex for money, and engagement in anal sex) were associated with infection status. Recommendations for the sexual health care of psychiatric patients in India are provided.

Adolescent↗
PubMed2006

Plasma adenosine deaminase activity among HIV1 Clade C seropositives: relation to CD4 T cell population and antiretroviral therapy.

BACKGROUND: Plasma adenosine deaminase and its isoenzymes(s) activities have been used as diagnostic marker for intracellular parasitism, including HIV infection, and malignancy of immune cells. HIV infection being primarily targeted against CD4 cells, it would be of interest to relate the activity of total plasma ADA and isoenzymes fractions to immune status and antiretroviral therapy. METHODS: In the present study, plasma total ADA activity (ADAT) including ADA1 and ADA2 isoenzyme(s) were assayed among HIV seropositive Clade C (n=90) comprising both asymptomatic (n=71) and symptomatic (n=19) and compared with that of HIV seronegatives (n=35). RESULTS: A significant increase in the activity of ADAT (16.30+/-0.80 v/s 6.18+/-0.30) as well as ADA1 (6.50+/-0.42 v/s 2.34+/-0.16) and ADA2 (9.79+/-0.53 v/s 3.85+/-0.23) isoenzyme(s) among the asymptomatic as well as the symptomatic subjects as compared to respective controls was noted. Increase in plasma ADAT activity, including ADA1 and ADA2 isoenzyme(s), were found to have negative correlation with CD4 counts (r, -0.273; p<0.05). The increased plasma ADAT activity among the asymptomatic HIV seropositive with CD4 counts>500 (13.2+/-1.65; p<0.01) as well as those who were on antiretroviral therapy (19.31+/-1.36; p<0.001) was evident. CONCLUSIONS: These findings suggest that plasma ADA can be a sensitive marker of an ongoing biological insult to host tissues either because of infection and/or side effects of medication. Measurement of plasma ADA activity, along with serological evidence for HIV infection may provide an alternate laboratory tool to monitor intracellular parasitism including secondary infection vis a vis the after effects of therapeutic outcome.

Adenosine Deaminase↗
PubMed2006

Quality of life in HIV subtype C infection among asymptomatic subjects and its association with CD4 counts and viral loads--a study from South India.

OBJECTIVE: To study the association between quality of life (QOL) domains and biological markers of disease progression of HIV infection, i.e. viral load (VL) and CD4 counts among asymptomatic subjects with HIV subtype C infection in South India. DESIGN: Quality of life was measured using the locally validated version of the WHOQOL HIV-BREF. The subjects were neurologically asymptomatic, non psychiatrically ill HIV infected men and women participating in a cohort study. RESULTS: The results indicated mixed findings, with some QOL dimensions being associated with high VLs and low CD4 counts while several others did not show any associations. Significant associations were seen between low CD4 counts and the psychological and social relationships domain, with lower mean scores in these domains being reported by subjects having CD4 counts <200/mm. However, there were no significant differences between the CD4 subgroups for the domains related to physical health, level of independence, environment, and spirituality domains. Significant lower mean QOL scores were found in the highest VL subgroup compared to other groups for the following WHOQOL HIV-BREF domains: physical, psychological, level of independence, and environmental. CONCLUSIONS: In this sample of HAART naïve asymptomatic HIV infected subjects, some QOL dimensions were associated with the biological markers of disease progression i.e. VL and CD4 counts, while several were not. The associations were significant only in the high VL and low CD4 groups.

Adult↗
PubMed2006

Presence of rabies specific immune complexes in cerebro-spinal fluid can help in ante-mortem diagnosis of human paralytic rabies.

BACKGROUND: Human rabies presents in two clinical forms, viz. furious or encephalitic and paralytic. Clinical diagnosis of paralytic form is difficult and requires laboratory confirmation. Presently available diagnostic techniques are not very sensitive for ante-mortem confirmation of rabies. OBJECTIVE: In the present study, we investigated whether presence of rabies specific immune complexes in cerebro-spinal fluid (CSF) of paralytic rabies patients could help in ante-mortem diagnosis of rabies. STUDY DESIGN: A capture ELISA based on monoclonal antibodies to rabies nucleoprotein (N) and glycoprotein (G) was developed to detect immune complexes to rabies N and G proteins. We studied CSF samples collected ante-mortem from 30 suspected paralytic rabies patients in whom diagnosis was later confirmed by autopsy. We included 30 CSF samples from people undergoing spinal anesthesia as negative controls and 30 CSF samples from other viral encephalitis as disease controls. RESULTS: Twenty-three out of 30 CSF samples (76.6%) showed presence of immune complexes to both rabies N and G proteins. None of the negative controls and CSFs from other confirmed viral infections were positive. Thus, the results were 100% specific and the sensitivity of this test was 76.6%. CONCLUSIONS: Detection of immune complexes to rabies antigens may be used as one of the techniques for rapid ante-mortem diagnosis of human rabies.

Adult↗
PubMed2006

Long term survival in subacute sclerosing panencephalitis: an enigma.

BACKGROUND: Subacute sclerosing panencephalitis (SSPE) usually has a progressive stereotypic downhill course and results in premature death. Long-term stabilization or remission is exceptional. OBJECTIVE: To analyze the profile of patients with a relatively 'benign' course who survive beyond 3 years. DESIGN: Descriptive analysis of 19 (16 male, 3 females)/307 (6.2%) patients with benign course who were evaluated at NIMHANS between January 1995 and December 2004. Their diagnosis was based on characteristic myoclonic jerks, elevated antibody titers against measles virus in CSF and periodic complexes in EEG. RESULTS: The mean age at onset of symptoms was 11.7+/-3.9 years and mean duration of follow-up from first symptom was 5.9+/-3.1 years (3-13.8 years). Their initial symptoms were seizures (7), myoclonus (6), visual disturbances (4), behavioral changes (1) and cognitive impairment (1). These patients had varied clinical course: stabilization in different stages for 6 months to 5 years (13), remissions for 6 months to 9 years and reversal of staging with functional recovery from being bed bound to ambulant (8). Their diagnosis was often delayed. Small sample size did not permit to analyze the influence of possible disease modifying agents used in 10 patients (isoprenosine-3, amantidine-4, oral steroids-4, methylprednisolone-1, intravenous immunoglobulin-1). CONCLUSIONS: Our observations suggest that SSPE may have a highly variable clinical course and warrants cautious approach for counseling at initial evaluation and while interpreting beneficial effect of disease modifying agent(s). There is a need to explore prognostic marker(s).

Adolescent↗
PubMed2006

Ante mortem diagnosis of human rabies using saliva samples: comparison of real time and conventional RT-PCR techniques.

BACKGROUND: Rabies is an enzootic and fatal disease and is still a major problem in developing countries. Ante mortem diagnosis in human cases is necessary for medical management of the patient and to ensure appropriate post-exposure treatment of contacts. Both conventional RT-PCR and Real time PCR (TaqMan) have been described for the detection of rabies virus RNA from saliva and tissue respectively, however to date, there have been no studies comparing conventional and real time PCR assays for detection of rabies virus nucleic acid using saliva samples for ante mortem diagnosis. OBJECTIVES: In this study, we evaluated the utility of conventional RT-PCR and SYBR Green I Real time PCR in the ante mortem diagnosis of rabies using saliva samples. STUDY DESIGN: Saliva samples collected from twenty-four patients presenting with typical clinical manifestations of rabies were tested in the two assays. RESULTS: Amongst the 24 samples tested, 21 samples (87.5%) were positive by either of the two molecular methods. Of these 21, rabies virus RNA was detected in 6/21 in the conventional RT-PCR assay while SYBR Green I Real time PCR could detect RNA in 18/21 samples. CONCLUSION: Real time PCR assay was more sensitive than conventional RT-PCR assay (sensitivity 75% versus 37%, p=0.0189). This study highlights the utility of molecular diagnostic tests in establishing ante mortem diagnosis of rabies using saliva samples within a few hours.

Adolescent↗
PubMed2006

Adult onset subacute sclerosing panencephalitis: clinical profile of 39 patients from a tertiary care centre.

Clinical and laboratory characteristics of 39 patients with adult onset subacute sclerosing panencephalitis (SSPE) are described and compared to those of juvenile onset patients regarding preceding measles, age at onset, gender, interval between onset and diagnosis, clinical profile, and course during follow up. Diagnosis was based on clinical and electroencephalographic findings and raised anti-measles antibody titres in cerebrospinal fluid. Mean age at SSPE symptom onset was 20.9+/-4.9 years and mean interval from onset to diagnosis was 6.3+/-9.6 months. Referral diagnosis was accurate in only 12 patients. Presenting symptoms included myoclonus, behavioural changes, seizures, and cognitive, visual, and extrapyramidal disturbance. All patients received symptomatic therapy; 19 also received disease modifying agents. Five of seven pregnant women had successful deliveries. The follow-up period varied widely (maximum 60 months, median 9 months). The profile of adult onset SSPE did not differ from the rest of the cohort, except for a longer interval between measles infection and symptom onset (p<0.0001). SSPE in adults poses diagnostic challenges for clinicians. A high index of suspicion and appropriate investigations are necessary for early diagnosis and counselling.

Adolescent↗
PubMed2006

Development and evaluation of a rapid IgM capture ELISA (JEV-Chex) for the diagnosis of Japanese encephalitis.

BACKGROUND: The IgM capture ELISA has been the most widely used diagnostic method for Japanese encephalitis. However, the lack of availability of validated commercial kits as well as the short shelf life of the kit reagents has limited the use of this technique to very few centres in Asia. OBJECTIVES: Development and evaluation of a rapid IgM capture ELISA (JEV Chex) in comparison to the conventional IgM capture ELISA. Produce key reagents such as cell culture derived JEV antigen and biotinylated monoclonal antibody which are stable at room temperature. STUDY DESIGN: The conventional IgM capture ELISA was modified to reduce the total assay time and two key reagents used in the assay JEV antigen and biotinylated anti-JEV monoclonal antibodies were rendered stable at room temperature using a special procedure. A multi-centric evaluation of this rapid ELISA was carried out using well characterized stored CSF and serum samples. Long term stability of the key reagents was also assessed over a period of 6 months. RESULTS: The rapid IgM capture ELISA developed by us showed complete concordance with the results obtained using the conventional ELISA at all the three centres where it was evaluated. In addition, the stability studies carried out with the inactivated cell culture antigen and the biotinylated monoclonal antibodies stored at room temperature for a period of 180 days revealed that both these reagents yielded consistent optical density values in the ELISA. CONCLUSIONS: The rapid ELISA format of the IgM capture ELISA (JEV-Chex) developed by us as well as the stability of reagents achieved by us in this study is what renders this rapid IgM capture ELISA very robust and user friendly since reagents can be stored at 4 degrees C by peripheral labs.

Aedes↗
PubMed2005

Screening for sexually transmitted infections at a DeAddictions service in south India.

OBJECTIVES: To estimate the lifetime prevalence of four sexually transmitted infections (STIs) and to identify correlates of these infections among patients seeking care for a substance use disorder at a specialized DeAddictions Unit in southern India. METHODS: Consecutive inpatients (n=361; 98% male; M age=36.7 years) admitted to DeAddictions Unit of the National Institute of Mental Health and Neuro Sciences in Bangalore, India, participated in a structured interview to obtain demographic, psychiatric, sexual behavior, and substance use data; each patient also provided a blood sample for serologic testing for HIV, chlamydia, syphilis, and hepatitis B. RESULTS: One-quarter of all patients tested positive for at least one STI. Lifetime seroprevalence rates were 12.9% for syphilis, 10.3% for chlamydia, 3.1% for hepatitis B, and 1.1% for HIV. Analyses did not reveal any consistent pattern of associations between STI status and sociodemographic, psychiatric, and sexual behavioral characteristics. CONCLUSIONS: All patients should receive a comprehensive sexual assessment during standard care; for those patients who report risky sexual practices, we recommend voluntary counseling and testing for STIs. Although we do not recommend universal testing for STIs at this time, this should be revisited based upon national surveillance data.

Adult↗
PubMed2005

Post harvest spoilage of sweetpotato in tropics and control measures.

Sweetpotato storage roots are subjected to several forms of post harvest spoilage in the tropical climate during transportation from farmers' field to market and in storage. These are due to mechanical injury, weight loss, sprouting, and pests and diseases. Sweetpotato weevil is the single most important storage pest in tropical regions for which no control measures or resistant variety are yet available. Several microorganisms (mostly fungi) have been found to induce spoilage in stored sweetpotatoes. The most important among them are Botryodiplodia theobromae, Ceratocystis fimbriata, Fusarium spp., and Rhizopus oryzae. The other less frequently occurring spoilage microorganisms include Cochliobolus lunatus (Curvularia lunata), Macrophomina phaseolina, Sclerotium rolfsii, Rhizoctonia solani, Plenodomus destruens. Microbial spoilage of sweetpotato is found associated with decrease in starch, total sugar, organic acid (ascorbic acid and oxalic acid) contents with concomitant increase in polyphenols, ethylene, and in some instances phytoalexins. Several methods are used to control microbial spoilage. Curing to promote wound healing is found as the most suitable method to control microbial spoilage. Curing naturally occurs in tropical climates where mean day temperature during sweetpotato harvesting season (February-April) invariably remains at 32-35 degrees C and relative humidity at 80-95%. Sweetpotato varieties varied in their root dry matter content, and low root dry matter content attributed for their high curing efficiency. Curing efficiency of varieties also differed in response to curing periods. Fungicide treatment, bio-control, gamma irradiation, hydro warming, and storage in sand and saw dust were found to have intermediate impacts in controlling spoilage and enhancing shelf life of sweetpotato roots. Breeding program has to be chalked out to develop new varieties suitable to curing under tropical conditions in addition to developing varieties having multi-spectrum resistance to major post harvest rot pathogens and sweetpotato weevils.

Food Contamination↗
PubMed2005

Neuropathology of HIV/AIDS with an overview of the Indian scene.

Neurological manifestations of HIV infection and AIDS are being recognized with a frequency that parallels the increasing number of AIDS cases. Next to sub-Saharan Africa, India has the second largest burden of HIV related pathology, essentially caused by HIV-1 clade C in both the geographic locales, in contrast to USA and Europe. But the true prevalence of HIV related neuroinfections and pathology is not available due to inadequate medical facilities, social stigma and ignorance that lead to underdiagnosis. Neurotuberculosis, followed by cryptococcosis and toxoplasmosis in various combinations are the major neuropathologies reflecting the endemicity and manifesting clinically by reactivation of latent infection. Discordance in the clinical prevalence of various infections, when compared to pathological studies highlight similarities in clinical, radiological modalities of diagnosis and inherent problems in establishing definitive diagnosis. Viral infections appear to be relatively rare. Inspite of heavy burden of HIV/AIDS, HIV associated neoplasia is infrequent, including primary CNS lymphomas. HIV encephalitis and HIV associated dementia are considered infrequent, though systematic studies have just been initiated in various centres. Peripheral neuropathy characteristically manifests with vasculitic neuropathy while diffuse infiltrative lymphocytosis syndrome (DILS) involving nerves has not been reported from India. Spinal cord pathology including vacuolar myelopathy is rare, even in asymptomatic cases. Till now the AIDS cases in India were drug naive but a new cohort of cases following initiation of HAART therapy as a national policy is soon emerging, altering the biology and evolution of HIV/AIDS in India. Lacunae in the epidemiology, diagnosis and study of biology of HIV/AIDS are outlined for future research.

Antiretroviral Therapy, Highly Active↗
PubMed2004

HIV-1 clade-C-associated "ALS"-like disorder: first report from India.

A patient of ALS-like disorder in an HIV-1 clade-C-infected heterosexual male is being reported. A 37-year-old gentleman presented with subacute, progressive asymmetrical onset of weakness and wasting of upper limbs associated with brisk muscle stretch reflexes and without any sensory or sphincter involvement. While nerve conduction tests were normal, the EMG of proximal and distal limb muscles on both sides revealed evidence of denervation and reinnervation. Routine blood and urine tests and investigations for underlying causes of motor neuron disease were noncontributory. He was HIV-1, subtype clade C seropositive. A diagnosis of HIV-related anterior horn cell disease was considered and zidovudine, lamivudine and nevirapine were started. After 1 month, there was a subjective improvement of 10% and objective improvement in strength of muscles of proximal upper limb on both sides by one grade power on MRC scale. Reports of amyotrophic lateral sclerosis (ALS)-like illness in HIV are sparse. The reversibility of "ALS"-like features in this subgroup of patients might offer an insight into the pathogenesis of amyotrophic lateral sclerosis. This is a first report of ALS-like illness caused by subtype C of HIV-1 strain.

Adult↗
PubMed2004

Structural and functional analysis of rice genome.

Rice is an excellent system for plant genomics as it represents a modest size genome of 430 Mb. It feeds more than half the population of the world. Draft sequences of the rice genome, derived by whole-genome shotgun approach at relatively low coverage (4-6 X), were published and the International Rice Genome Sequencing Project (IRGSP) declared high quality (>10 X), genetically anchored, phase 2 level sequence in 2002. In addition, phase 3 level finished sequence of chromosomes 1, 4 and 10 (out of 12 chromosomes of rice) has already been reported by scientists from IRGSP consortium. Various estimates of genes in rice place the number at >50,000. Already, over 28,000 full-length cDNAs have been sequenced, most of which map to genetically anchored genome sequence. Such information is very useful in revealing novel features of macro- and micro-level synteny of rice genome with other cereals. Microarray analysis is unraveling the identity of rice genes expressing in temporal and spatial manner and should help target candidate genes useful for improving traits of agronomic importance. Simultaneously, functional analysis of rice genome has been initiated by marker-based characterization of useful genes and employing functional knock-outs created by mutation or gene tagging. Integration of this enormous information is expected to catalyze tremendous activity on basic and applied aspects of rice genomics.

Chromosomes, Plant↗
PubMed2003

T helper responses to Japanese encephalitis virus infection are dependent on the route of inoculation and the strain of mouse used.

T helper cytokine and IgG subtype responses were studied in three strains of mice (C57BL/6J, Swiss albino, BALB/c; n=90 per strain) immunized with live Japanese encephalitis virus (JEV) by intraperitoneal (IP), subcutaneous (SC) and peroral (PO) routes. Lymphocytes obtained from the spleens of immunized and control mice were stimulated in vitro with JEV for 48 h and the supernatants were assayed for the presence of the cytokines IL-4 and IFN-gamma. JEV-specific IgG isotypes were also measured in the sera of immunized mice. T helper cytokine responses in mice immunized with JEV were found to be strain- and route-specific in the three species tested. Moreover, they were also dependent on the type of immunogen used (live vs killed virus), as well as the number of doses administered. C57BL/6J and BALB/c mice were more uniform in their T helper responses compared with the outbred Swiss albino mice and induced a good Th1 response (P<0.001). Among the three routes evaluated, the IP and SC routes consistently elicited a Th1 response compared with the PO route (P<0.001), where an initial Th2-type response reverted to a Th1 response after repeated immunization. Live JEV induced a Th1 response while the commercial killed vaccine induced a predominant Th2 profile.

Administration, Oral↗