Biomedical subjects
R Kumar
Publications and source records attributed to R Kumar.
Mast cell and Mycobacterium leprae in experimental leprosy.
The association of mast cells and lepra bacilli was studied in the foot pad skin of immunosuppressed mice inoculated with 10(5) lepra bacilli. The mice were killed at intervals varying from 2 1/2-14 months postinoculation. M. leprae are found in large numbers in nerves, blood vessels, muscle fibres, hair follicles, sweat and sebaceous glands. Mastocytosis and extensive degranulation are seen at similar sites. Since these are the structures most affected in leprosy where the lepra bacilli and degranulating mast cells accumulate, there appears a close relationship between the two. This could be due to the composite role of mast cells in host tissue response and mastocytosis and degranulation may be related to this.
Renal failure as the presenting feature of light chain myeloma of kappa type.
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Immunological studies in typhoid fever. II. Cell-mediated immune responses and lymphocyte subpopulations in patients with typhoid fever.
The development of the cell-mediated immune response (CMIR) to antigens prepared from Salmonella typhi was investigated in patients suffering from typhoid fever and in normal healthy subjects. The leucocyte migration inhibition test, blast transformation of lymphocytes and active rosette-forming cells were used for detecting CMIR. Peripheral blood lymphocytes were analysed for the numbers and proportions of B lymphocytes, T lymphocytes and their subpopulations with receptors for IgM (T micro) or IgG (T gamma) and cells with Fc receptors for IgG. These parameters were correlated with the duration and the severity of illness. The uncomplicated cases of typhoid fever were found to have an intact CMIR as compared to the complicated cases. The ratio of T lymphocyte subpopulations was grossly imbalanced in typhoid patients, the numbers of T lymphocytes and their subpopulations were further altered in he complicated cases as compared to uncomplicated cases. The present study demonstrates a depressed state of CMIR in complicated patients with typhoid fever. CMIR may thus emerge as the cardinal point for recovery in typhoid fever rather than the specific antibodies. The study further demonstrates that imbalance within the subsets of T lymphocytes may be responsible for the depressed state of CMIR in complicated cases of typhoid fever.
A study of humoral and cell-mediated immune response following typhoid vaccination in human volunteers.
The specific antibody response to O, H and Vi antigens, levels of IgG, IgM, IgA, and C3 presence of soluble immune complexes, in vitro tests of cellular immunity and subsets of lymphocytes in the peripheral blood were investigated in human volunteers after a single dose of 0.1 ml intradermal typhoid vaccination. The results indicated that typhoid vaccination induced antibody formation, slightly increased IgA levels and led to a decrease in C3 which was probably due to immune complex formation. There was also a relative increase in circulating Fc-IgG receptor-bearing lymphocytes and T-gamma cells after vaccination. In those subjects who showed specific cellular immunity before vaccination, a transient depression in lymphocyte transformation and a negative leucocyte migration inhibition test with typhoid baccilli occurred post-vaccination. These findings raised doubts over the advantages of giving typhoid vaccine during an epidemic.
Altered vitamin-D metabolism due to anticonvulsant drugs in epileptic children.
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On a new Bifurcohaptor species (Monogenea) from Bagarius bagarius (Pisces) in India.
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Peak expiratory flow rate in relation to anthropometric measurements in normal Indian subjects.
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Peak expiratory flow rate in relation to body surface area in north Indian adults.
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Adverse reaction after measles immunization in a rural population.
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Diaphragmatic herniorrhaphy in a cow.
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The isolation and identification of 5,6-trans-25-hydroxyvitamin D3 from the plasma of rats dosed with vitamin D3. Evidence for a novel mechanism in the metabolism of vitamin D3.
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Synthesis and biological activity of vitamin D3 3 beta-sulfate. Role of vitamin D3 sulfates in calcium homeostasis.
To determine the biological activity of vitamin D sulfates, we synthesized vitamin D3 3 beta-sulfate and tested its biological activity in vitamin D-deficient hypocalcemic rats. When vitamin D3 sulfate was administered as a single oral dose of 208,000 or 416,000 pmol (100 micrograms or 200 micrograms), it increased active calcium transport in the duodenum and was also able to mobilize calcium from bone and soft tissue. Dose levels below this failed to elicit a response. Vitamin D3 itself was active at doses as low as 260 pmol when administered in this manner. In order to test the biological activity of vitamin D3 sulfate in various doses when administered chronically, we tested the biological activity of vitamin D3 sulfate after 5 days or oral dosing: vitamin D3 sulfate was active at doses of 52,000 pmol/day (25 microgram), whereas vitamin D3 was active at doses of 65 to 260 pmol/day over a period of 5 days. When administered as a single intravenous dose, vitamin D3 sulfate exhibited no biological activity in doses as high as 52,000 pmol. Vitamin D3, however, was active at a dose of as low as 65 pmol. We conclude that vitamin D3 sulfate, a metabolite of vitamin D3 of heretofore unknown biological activity, is considerably less active than vitamin d3 itself.
Metabolism of sitosterol by a Pseudomonas species.
Fermentation of sitosterol by a Pseudomonas species (SK-25) resulted in the formation of 5-stigmastene-3 beta, 7 alpha-diol; 5,6 alpha-epoxy-5 alpha-stigmastan-3 beta-ol; 5,6 beta-epoxy-5 beta-stigmastan-3 beta-ol and 5 alpha-stigmastan-3 beta, 5,6 beta-triol. The metabolites were characterized by a variety of conventional chemical and spectrometric techniques.
Production of a polar metabolite of 1,25-dihydroxyvitamin D3 in a rat liver perfusion system.
When radiolabeled 1,25-dihydroxyvitamin D3 is added to the perfusion medium of a rat liver perfusion system, a polar metabolite of 1,25-dihydroxyvitamin D3 is formed in the liver and excreted in the bile. Addition of radiolabeled 1,25-dihydroxyvitamin D3 to the perfusion medium without a liver in the circuit results in no formation of the polar metabolite. These data suggest that a polar metabolite of 1,25-dihydroxyvitamin D3 is formed in the liver prior to being excreted in bile. Moreover, it is likely that polar metabolites of 1,25-dihydroxyvitamin D3 present in the bile of rats in vivo are formed in the liver.
Small renal carcinoma with large retroperitoneal hemorrhage: diagnostic considerations.
Two cases of small peripheral papillary renal carcinoma causing large spontaneous perirenal hemorrhages are presented. The value and limitations of computerized tomography, ultrasonography, arteriography, and percutaneous aspiration biopsy in these cases are discussed. The need for careful explorative surgery and dissection of the specimen is emphasized. Excretory urography should be the first examination in all patients with renal pain and signs of internal bleeding. Arteriography should be done when the diagnosis is not evident.