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Biomedical subjects

K Saha

Publications and source records attributed to K Saha.

At least 145 records · Page 8Linked to original sources

Effects of antibacterial agents on the complement system.

The alteration of serum complement profile following therapy with various antibiotics was studied in 23 hospitalized patients and in 10 human volunteers. Tetracycline, chloromycetin, ampicillin, and streptomycin reduced serum CH50 and C3 levels in the inpatients. Tetracycline administration for three consecutive days in four normal subjects decreased serum CH50, C1q, C3, and C4 levels on day 4. However, these parameters returned to near-normal levels on day 7 following the withdrawal of the drugs. On the other hand, septran administered in six normal individuals for three consecutive days had no significant effect on the complement system. In vitro studies as well as in vitro studies in guinea pigs treated with various antibiotics showed almost parallel results.

Animals↗

Profile of complement components in patients with severe burns.

Twelve adults hospitalized with extensive burns formed the basis of the present study. On admission, blisterfluid and serum were collected from each patient and subsequently serum only obtained on 3rd, 7th, 14th, 21st, and 28th day of hospital stay. Complement components C1q, C3, C4, and C5 were measured in these samples by single radial immunodiffusion technique. It was observed that immediately after the thermal trauma there was a sudden and profound fall in serum levels of the early and late complement components vis-à-vis their appearance in blisterfluid. However, their levels in the latter were significantly lower than in the former. The mean serum levels of these components gradually increased up to the 14th day after burns and thenceforth leveled off, although normal serum levels for C1q and C3 were never achieved. Three patients died between 6 and 24 days after trauma. Individual variations in the complement profile were observed and no correlation between the serum levels of complement components and prognosis of burned patients was seen.

Adolescent↗

Decreased gut-associated IgA levels in patients with typhoid fever.

Gut and serum immune responses were studied in twenty-two patients with bacteriologically proved typhoid fever at different stages of the illness and six volunteers after parenteral immunizations with heat-killed typhoid vaccine. Whereas the former group had some specific antibodies in their intestinal aspirates and significant specific antibody responses in their sera, the latter could only mount a serum antibody response. Moreover, the intestinal IgA levels in the patients remained significantly decreased throughout the whole course of the illness, but a rise of IgG and IgM was observed in their jejunal secretions. In contrast, the levels of all the three major classes of serum immunoglobulins IgG, IgM and IgA were raised in the patients, as opposed to the volunteers, in whom only IgG and IgM levels were increased. It was inferred that the subjects with deficit of intestinal IgA, and thus lacking protective mucosal barrier, are more prone to develop typhoid fever.

Antibody Specificity↗

Impairment of Jones-Mote hypersensitivity and specific antibody response against depolymerized flagellin in lepromatous leprosy.

Cutaneous hypersensitivity and antibody-producing capacity were assessed in patients with lepromatous leprosy with defective immunity, by immunizing them with monomeric flagellin from Salmonella adelaide. Results were compared with those of controls, matched for age and sex, derived from similar socioeconomic stratum, but without any defect of the immunological system. In contrast to the normal individuals, who showed Jones-Mote type of hypersensitivity, no lepromatous patient could mount any 'delayed-in-time' cutaneous hypersensivivity reaction against an intradermal challenge of monomeric flagellin. However, when immunized through the subcutaneous route, both groups could produce adequate amounts of specific serum antibody. In addition to this unique split tolerance found in all lepromatous patients, some patients showed low levels of 'natural' IgM antibody, reduced formation of specific antibody when immunized through the subcutaneous route, and incomplete maturation of IgG class of anti-flagellin antibody. When immunized by the intradermal route, however, production of both anti-flagellin antibody and maturation of IgG antibody was significantly inhibited in normal adults but not in lepromatous patients. Thus, contrary to the earlier concept of hyperactivity of the humoral immune apparatus in lepromatous leprosy, the present study detected B-cell hypofunction in some patients.

Adult↗