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Biomedical subjects

V K Sharma

Publications and source records attributed to V K Sharma.

At least 343 records · Page 19Linked to original sources

Enzyme immunoassay of serum beta-2-microglobulin levels in various histological forms of leprosy with special reference to its elevation in type I and type II lepra reactions.

The mean beta-2-microglobulin level in serum (3,362 +/- 2,494 micrograms/liter) for 76 leprosy patients, including 9 borderline-tuberculoid, 8 borderline-borderline, 9 borderline-lepromatous, and 16 lepromatous-lepromatous patients and 34 patients with type I or type II lepra reactions, was significantly higher (P less than 0.001) than that (2,122 +/- 1,844 micrograms/liter) for 35 normal subjects. It decreased significantly (P less than 0.001) as the disease glided down from borderline tuberculoid (3,173 +/- 899 micrograms/liter) to the lepromatous end (1,813 +/- 1,391 micrograms/liter). At the onset of type I or type II reaction, the mean beta-2-microglobulin level in serum increased (4,447 +/- 2,863 micrograms/liter), and it remained unchanged (4,433 +/- 2,623 micrograms/liter) after clinical remission. The beta-2-microglobulin level in serum decreased in 55.5% of the patients tested after subsidence of reaction. The level was significantly higher in patients with type II reactions (5,433 +/- 3,299 micrograms/liter) than in patients with type I reactions (3,558 +/- 2,171 micrograms/liter).

Adolescent↗

Pentamidine-induced diabetes mellitus.

Twelve cases of diabetes mellitus following pentamidine isethionate ( Lomidine ) treatment for antimonial -resistant cases of kala-azar are reported. 11 were found to be insulin-dependent and one insulin-independent. One patient died at home two months later and the rest still had diabetes mellitus at follow-up after two to five years.

Amidines↗

Measurement of cytosolic free calcium concentration in isolated rat ventricular myocytes with quin 2.

Cytosolic free calcium concentration was determined in isolated ventricular myocytes from adult rats with the calcium-sensitive indicator, quin 2. The fluorescence signal from resting cells indicated that cytosolic free calcium concentration was 181 +/- 18 nM (mean +/- SEM, n = 18). Inhibition of the sodium-potassium pump with strophanthidin (0.1 mM) resulted in an increase of cytosolic free calcium concentration from 186 +/- 17 to 736 +/- 129 nM (n = 6). The results indicate that it is possible to measure cytosolic free calcium concentration in cardiac muscle cells that have been isolated enzymatically. Moreover, they confirm the observation that inhibition of the sodium-potassium pump increases cytosolic free calcium concentration, presumably via the sodium-calcium exchange mechanism.

Aminoquinolines↗

Decreased beta-adrenergic receptors in rat heart in streptozotocin-induced diabetes: role of thyroid hormones.

The effect of streptozotocin-induced diabetes on the beta-adrenergic receptor-coupled adenylate cyclase was studied in rat heart particulate fractions. Streptozotocin treatment decreased the number of myocardial beta-adrenergic receptors by 34% with no change in the apparent affinity of these receptors for [3H]dihydroalprenolol. The maximal isoproterenol-activated accumulation of cAMP in streptozotocin-treated rat hearts was decreased by only 10%. Insulin administration to streptozotocin-treated rats increased the number of myocardial beta-adrenergic receptors to near or above control levels. Administration of L-T4 to streptozotocin-treated rats had the same effect. Total T4, free T4, and total T3 levels were all significantly decreased in the diabetic animals. Administration of insulin to streptozotocin-treated rats increased the serum thyroid hormone levels toward or above the levels found in control animals. Streptozotocin-induced diabetes had no significant effect on cardiac beta-adrenergic receptor number in thyroidectomized rats. Insulin did not elevate cardiac beta-adrenergic receptor number in thyroidectomized diabetic rats. The decrease in the number of myocardial beta-adrenergic receptors occurring in diabetes mellitus is probably mediated through thyroid hormones.

Adenylyl Cyclases↗

Polyethylene glycol precipitates in serum during and after erythema nodosum leprosum--study of their composition and anticomplementary activity.

Polyethylene glycol (PEG) precipitates obtained from sera were characterized and quantitated in 20 borderline lepromatous (BL) and polar lepromatous (LL) patients with moderate to severe erythema nodosum leprosum (ENL) before and four weeks after treatment with anti-ENL drugs, e.g., cortisone, clofazimine, chloroquine, or aspirin. Although the clinical severity of ENL subsided, there was no significant clearance of material that precipitates with PEG from the circulation. These precipitates had variable anticomplementary properties.

Antigen-Antibody Complex↗

Left atrial myxoma. An ultrastructural study.

Electron microscopic observations of 4 excised cardiac myxomas were made. All were present in the left atrium and all but one had a stalk. The hearts were otherwise normal. Several types of mesenchymal cells in varying stages of differentiation were identified. Cells having some features of smooth muscle, fibroblasts, and endothelium were observed. Some cells having features of both smooth muscle and fibroblasts namely, myofibroblasts were also encountered. Macrophages, lymphocytes and plasma cells were also seen in small numbers. Hematopoietic foci and calcification were not seen in any of our cases. Ultrastructurally, fine electron dense granules and only stray collagen fibres were noted in the matrix. Myxomas possibly represent either hyperplasia or a true neoplasm of the subendocardial multipotential cells that are capable of differentiating into various types of mesenchymal elements.

Adolescent↗

Production, partial purification and characterization of Salmonella heat-labile enterotoxin.

A heat-labile enterotoxin possessing both diarrheogenic and skin permeability reactions has been isolated from Salmonella weltevreden. The enterotoxin was mainly located intracellularly in the cell wall fraction. By chemical and physical techniques such as EDTA treatment of cell walls, fractional ammonium sulphate precipitation and continuous sucrose gradient centrifugation of cell sap (cell free extract) and gel filtration chromatography of culture supernatant, the enterotoxin has been partially purified. The enterotoxin resembled the heat labile enterotoxin of E. coli and the cholera toxin with respect to its thermal stability; however, it was different in its sensitivity to acidic and alkaline pH. Its activity was lost completely on treatment with Pronase and trypsin. The toxin appears to be of a high molecular weight and its enterotoxic activity is associated with a protein moiety.

Bacterial Toxins↗

Enterotoxigenicity and invasiveness of Salmonella species.

A large number of enterotoxigenic strain was encountered in a group 56 Salmonella cultures belonging to 8 species viz., S. alachua, S. anatum, S. dublin, S. Enteritidis, S. hindmarsh, S. newport, S. typhimurium, S. weltevreden, and 5 serotypes of S. arizona (16:z4:--; 48:1,v:z56; 53:z52:z53; 60:r:z; 60:i:z53). These cultures were isolated mainly from humans and animals suffering from gasteroenteritis. The enterotoxigenic (diarrhoeagenic) Salmonella cultures possess capacities for both skin permeation and epithelial penetration (invasiveness). Preliminary characterization revealed that Salmonella enterotoxin is a heat-labile protein of high molecular weight. It is suggested that enterotoxigenic and invasive properties play a vital role in the pathogenesis of Salmonella diarrhoea.

Animals↗

Inhibitory effect of indomethacin on skin permeability reactions mediated by heat-labile enterotoxins of Salmonella weltevreden, Escherichia coli and Vibrio cholerae.

Indomethacin, a rapid and intense inhibitor of prostaglandin synthesis, was used with a view to find out similarity in secretory mechanism of heat-labile enterotoxins of three diarrhoea producing enteric bacteria viz., Salmonella weltevreden, Escherichia coli and Vibrio cholerae in rabbits. A significant inhibition (90% to 94%) of biological activity of indomethacin pretreated Salmonella enterotoxin was evident in indomethacin treated rabbits, whereas the biological activity was found comparatively low (28% to 76%) in the untreated enterotoxin preparations. In contrast, the skin permeability reaction to cholera toxin remained unaltered in the absence of pretreatment of cholera toxin with indomethacin and it dropped to 55% in pre-treated toxin preparations. There was complete inhibition of biological activity of E. coli enterotoxin which did not receive indomethacin pretreatment. Based on these observations it may be inferred that indomethacin inhibits skin permeability response of heat labile enterotoxin of S. weltevreden both by blocking the effect of prostaglandins (Blocking mechanism) as well as by prostaglandin-adenyl cyclase pathway. The reduction in the biological activity of cholera toxin seems to be occurring through blocking of prostaglandins by indomethacin. In case of E. coli enterotoxin the inhibition mechanism seems operating through prostaglandin-adenyl cyclase system. These observations indicate that the Salmonella enterotoxin shares some similarity with enterotoxins of E. coli and Vibrio cholerae in respect of mechanism of action.

Animals↗

Serum immunoglobulins an autoantibodies during and after erythema nodosum leprosum (ENL).

Sera from 20 patients with lepromatous leprosy complicated by erythema nodosum leprosum (ENL) were collected at the time of acute reaction and then after clinical cure four weeks later. Anti-ENL drugs used were: prednisolone (11 patients), chloroquin (6 patients), and clofazimine (3 patients). Immunoglobulins M, G, and A and autoantibodies, namely, antithyroglobulin antibody (ATA), antinuclear antibody (ANA), and rheumatoid factor (RF), were measured in these 20 paired serum samples. The mean serum concentration of IgG showed a significant elevation after clinical subsidence of the reaction, mainly in the prednisolone treated group; while those of IgM and IgA varied only marginally. Autoantibodies were detected in nine patients. Of these, three patients developed these antibodies only after remission of the reaction. Treatment with prednisolone and chloroquin, although causing subsidence of ENL, resulted in an increased incidence of ATA and/or ANA. Furthermore, it was observed that longer duration of illness, higher age group, and history of repeated attacks of ENL predisposed these patients to enhanced autoantibody formation.

Adult↗