Indian J Med Res
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Association of HLA-DR2 genes/gene products has been shown with pulmonary tuberculosis (PTB) patients in India. In the present study, the influence of HLA-DR2 and non-DR2 genes/gene products on immunity to tuberculosis has been studied. Plasma samples of -DR2 positive patients (active and inactive TB) showed a higher antibody titre to Mycobacterium tuberculosis culture filtrate antigens than non-DR2 (-DR2 negative) patients. ⋯ Further, an inversional correlation between antibody titre and spontaneous as well as antigen induced lymphocyte response (measured by 3H thymidine uptake and expressed as counts per minute) was seen in HLA-DR2 positive active PTB patients than non-DR2 patients. The present study suggests that HLA-DR2 genes/gene products may be associated with a regulatory role in the mechanism of disease susceptibility to tuberculosis. The genes while augmenting the humoral immune response, they suppress the spontaneous and antigen induced lymphocyte response in -DR2 positive patients with active disease.
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The efficacy of pentoxifylline--a haemorrheologic agent along with aspirin--an analgesic agent was evaluated in the amelioration of the tissue damage due to experimentally induced frostbite in 5 groups (20 each) of rats with body weights ranging between 175 and 200 g. Frostbite was produced experimentally in the hind limbs by exposing the animals to -15 +/- 1 degrees C for 1 h using the harness technique, with simultaneous recording of rectal and environmental temperatures. ⋯ The findings of this preliminary study have brought to light the potential usefulness of these drugs in the treatment of frostbite. The combined pharmacological properties of these two drugs might have altered the haemorrheologic status of blood and produced the curative beneficial effect in improving tissue survival following experimentally induced frostbite in rats.
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Vibrio cholerae produce a variety of extracellular products that have deleterious effects on eukaryotic cells. The massive diarrhoea produced by V. cholerae is caused by cholera toxin (CT). CT is composed of 1A and 5B units. ⋯ Besides CT, other bacterial toxins like Escherichia coli LT, Salmonella toxin, Shigella toxin and Campylobacter toxin also possess A-B structure. The structure and function of E. coli LT resembles closely that of CT. Most of the bacterial toxins exert their effect through involvement of ADP-ribosylating proteins whereas other toxins involve guanylate cyclase system, calcium and protein kinases for their ultimate action.
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A simple particle immunoassay based on the coagglutination (CoA) of Staphylococcus aureus strain Cowan 1 coated with heat labile enterotoxin (LT) specific antibodies was evaluated to detect LT in the cell lysates of blood agar grown Esch. coli. Among strains of Esch. coli isolated from 2661 patients with acute diarrhoea, isolates from 609 patients demonstrated LT production by CoA test. ⋯ A comparison of CoA with classical rabbit ileal loop and skin permeability factor assay for 100 strains showed 86, 69 and 83 LT positive strains respectively. CoA proved a more specific, simple, rapid and sensitive assay which may be useful for screening of large number of Esch. coli isolates in epidemiological investigations.
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Thirty enterotoxigenic Esch. coli (ETEC) strains of predominant serogroups, isolated from patients with diarrhoea in Ludhiana, Punjab were investigated for expression of heat labile (LT) enterotoxin and colonization factor antigens (CFAs) on repeated subculture. These belonged to serogroup 078 (10), 080 (2), 0114 (6), 020 (3), 0128 (3), 0153 (2) and 08 (4) respectively. ⋯ Three strains of serogroup 0114 and one of 080 failed to express CFA while one strain each of serogroups 080, 0114, 020 and 08 failed to elaborate LT in the 8th subculture. Only 25 and 19 isolates were detected as stable producer of LT and CFAs up to 10th subculture.