Browsing by Author "S. Sundar"

Now showing 1 - 4 of 4
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    Correlation between clinical features and degree of immunosuppression in HIV infected children
    (2008) D. Agarwal; J. Chakravarty; S. Sundar; V. Gupta; B.D. Bhatia
    We conducted this study to find out correlation of CD4% with clinical status in 102 HIV infected antiretroviral naïve children. Mean age of presentation was 4.8 years. Perinatal transmission was the commonest mode of transmission (94%). Fever (53%), chronic diarrhea (36%), and cough (29%) were the commonest presenting symptoms. Protein energy malnutrition was seen in 56.7% of children. 33.3% children were asymptomatic, whereas 45.1% were in WHO clinical stages III and IV at the time of presentation. The most common opportunistic infection was tuberculosis. CD4% correlated significantly with the deterioration of the WHO clinical stages (P<0.01) and increasing grades of protein energy malnutrition (P<0.05).
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    Diagnostic tests for kala-azar: a multi-centre study of the freeze-dried DAT, rK39 strip test and KAtex in East Africa and the Indian subcontinent
    (2008) M. Boelaert; S. El-Safi; A. Hailu; M. Mukhtar; S. Rijal; S. Sundar; M. Wasunna; A. Aseffa; J. Mbui; J. Menten; P. Desjeux; R.W. Peeling
    Three diagnostic tests for visceral leishmaniasis (VL), the freeze-dried direct agglutination test (FD-DAT), the rK39 dipstick and a urine latex antigen test (KAtex), were evaluated for use in primary care in East Africa and the Indian subcontinent. Clinical suspects were prospectively recruited and tissue, blood and urine samples were taken. Direct microscopic examination of tissue smear, and FD-DAT, rK39 and KAtex were performed. Sensitivity and specificity with 95% credible intervals were estimated using Bayesian latent class analysis. On the Indian subcontinent both the FD-DAT and the rK39 strip test exceeded the 95% sensitivity and 90% specificity target, but not so in East Africa. Sensitivity of the FD-DAT was high in Ethiopia and Kenya but lower in Sudan, while its specificity was below 90% in Kenya. Sensitivity of the rK39 was below 80% in the three countries, and its specificity was only 70% in Ethiopia. KAtex showed moderate to very low sensitivity in all countries. FD-DAT and rK39 can be recommended for clinical practice on the Indian subcontinent. In East Africa, their clinical use should be carefully monitored. More work is needed to improve existing formats, and to develop better VL diagnostics. © 2007 Royal Society of Tropical Medicine and Hygiene.
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    Human placental extract offers protection against experimental visceral leishmaniasis: A pilot study for a phase-I clinical trial
    (2008) D. Chakraborty; J.M. Basu; P. Sen; S. Sundar; S. Roy
    An aqueous extract of human placenta (HPE) was found to offer protection against established experimental visceral leishmaniasis in BALB/c mice and hamsters, whether the Leishmania donovani strain involved was one that was sensitive or resistant to pentavalent antimony. Intraperitoneal administration of the extract, into mice or hamsters that had been infected 2 months previously, led to antileishmanial T-cell proliferation among splenic mononuclear cells, the generation of host-protective cytokines (interferon-γ, tumour necrosis factor and interleukin-12) and the upregulation of the expression of inducible nitric oxide synthase (and subsequent NO generation) in splenocytes. Furthermore, splenic macrophages from the HPE-treated mice showed increased generation of reactive oxygen species and enhanced surface expression of antigens of major histocompatibility complex class II (MHCII), and the extract restored the otherwise-defective antigen-presenting ability of the macrophages. Thus, in mice and hamsters infected with L. donovani, HPE therapy can stimulate both arms of the host's immune system and favour the complete resolution of the leishmanial infection. Among five human cases of visceral leishmaniasis, 30 daily intramuscular injections of HPE, at doses much lower than those used in the experimental infections, also gave very promising results. Based on the results of this pilot study, a further evaluation of the efficacy of HPE therapy, which may offer a cost-effective way of improving the treatment of antimony-resistant cases of visceral leishmaniasis, is being undertaken. © 2008 The Liverpool School of Tropical Medicine.
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    Prophylactic efficacy of high-molecular-weight antigenic fractions of a recent clinical isolate of Leishmania donovani against visceral leishmaniasis
    (2008) P. Tripathi; S.K. Gupta; S. Sinha; S. Sundar; A. Dube; S. Naik
    T-cell mediated immune responses are key determinants to the natural course of infection caused by intracellular parasites such as Leishmania. Thus, T-cell activating proteins of these microbes continue to generate active interest particularly in view of their possible role in the design and development of newer and more effective vaccines. We have recently reported the presence of T-cell immunostimulatory antigens with the high-molecular-weight (MW) fractions (134-64.2 kDa) of whole Leishmania donovani antigen (strain 2001), which stimulated variable amounts of IFN-γ, IL-12 and IL-10 in exposed immune individuals. The present study was undertaken to further evaluate these high-MW antigenic fractions (MW range >100-60 kDa) for potential protective efficacy. The high-MW region of the parasite was resolved into five antigenic fractions (Prep A-E) using continuous elution gel electrophoresis. Prior to in vivo protection studies in hamsters, these fractions were used to evaluate in vitro cellular responses in eight Leishmania-exposed individuals and treated cured hamsters. The protective efficacy of prep (A + B), C, D and E in combination with BCG was evaluated in inbred hamsters using standard immunization protocol. Proliferative responses were seen in all eight of eight exposed individuals to prep D [median stimulation index (SI): 5.2 (range 3.9-7.1)] and E [median SI: 5.6 (range 4.4-8.2)], five of eight individuals to prep B and prep C and three of eight to prep A [median SI: 0.2 (range 0.1-7.2)]. The median proliferative responses to prep D and prep E were significantly higher than to fraction prep A; (P < 0.05) but not to prep B and prep C. However, prep A-E induced equivalent levels of IFN-γ, IL-10 and IL-12 cytokines. Fractions D and E also exhibited marked parasite inhibition in spleen (52.5% and 73.7%) and liver (65% and 80.2%) as compared with prep (A + B) (23% in spleen and 24% in liver) and prep C (38% in spleen and 24% in liver). Prep D and prep E vaccinated animals showed higher in vitro stimulatory responses (mean SI: 6.6 and 8.8) and nitric oxide (NO) induction (mean NO levels: 6.4 and 10.7 μg/ml) against whole cell extract as compared with other groups. The protection also correlated with presence of suppressed Leishmania-specific IgG levels in prep D and prep E immunized hamsters. These studies indicate the presence of immunostimulatory and protective molecules in 60-80 kDa region of L. donovani, which may be further exploited for developing a subunit vaccine. © 2008 The Authors.