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Biomedical subjects

A K Sharma

Publications and source records attributed to A K Sharma.

At least 379 records · Page 21Linked to original sources
PubMed1987

Effects of continuous subcutaneous insulin infusion on renal morphology in experimental diabetes. I. Blood glucose levels, body size, kidney weight and glomerulotubular morphometry.

Observations have been made over a period of 16 weeks on three groups of rats: controls, untreated streptozotocin-diabetics and diabetics treated with continuous subcutaneous insulin infusion. Good control of circadian and diurnal blood glucose levels was achieved in the insulin-treated diabetics. Body weights and tibial lengths were reduced in untreated diabetics and improved, but not normalized, by insulin therapy. Kidney weights were similar in all groups. Glomerular size and number, tubule volume, glomerular basement membrane volume and surface area were essentially the same in all groups. However, the untreated diabetics possessed tubules of larger diameter and shorter length than those in controls. Both variables were preserved at normal values by insulin infusion therapy. These results illustrate the value of early blood glucose control for preventing at least some of the structural alterations associated with experimental diabetic nephropathy.

Animals↗
PubMed1987

Effects of continuous subcutaneous insulin infusion on renal morphology in experimental diabetes. II. Glomerular basement membrane thickness.

Stereological studies were performed on renal glomeruli from control rats, untreated streptozotocin-diabetic rats and diabetics treated by subcutaneous infusion of insulin for 16 weeks. Estimates of glomerular basement membrane thickness were obtained by dividing membrane volume by membrane surface area. In addition, arithmetic and harmonic mean thicknesses were calculated from orthogonal intercept lengths, and used to provide information on the variability of basement membrane thickness. In untreated diabetics, both arithmetic and harmonic mean thicknesses were significantly greater than values found in control animals. The thickening of the basement membrane appeared to be generalized rather than markedly focal. All thickness variables were normalized by insulin infusion therapy. These findings underline the importance of good glycaemic control and early intervention in experimental diabetes and one of its main complications.

Animals↗
PubMed1987

Histopathologic and electron microscopic studies on the acute toxicity of ochratoxin A in rats.

Ochratoxin A was given by gavage to male rats. Moribund and dead animals were necropsied, and the surviving rats, including the controls, were killed 48 hours after dosing. Many of the principal rats were moribund, or began dying, within 12 to 24 hours after dosing. Lesions suggestive of disseminated intravascular coagulation were seen by light microscopy as early as 12 hours after dosing; fibrin deposits were in the spleen, brain choroid plexus, glomerular capillaries, liver, and heart. Renal tubular nephrosis, hepatic and lymphoid necrosis, and necrotic enteritis with villous atrophy were also seen. Electron microscopy demonstrated fibrin strands mixed with degranulated platelets, necrotic leukocytes, and swollen endothelial cells in glomerular capillaries. Myocardial changes included focal supercontracted sarcomeres adjacent to intercalated disks. Swollen sarcolemma, lysed myofibrils and fragmented Z-bands with interstitial edema, vascular thrombosis, and endothelial damage were also seen. The acute pathologic changes induced by ochratoxin A in the intestine, liver, and lymphoid tissues were more obvious than the tubular nephrosis, and the development of a disseminated intravascular coagulation-like syndrome with myocardial changes was a complicating factor.

Animals↗
PubMed1987

Inhibition of somatomedin-like activity by serum from streptozotocin-diabetic rats: prevention by insulin treatment and correlation with skeletal growth.

Diabetes mellitus was induced in rats by streptozotocin. This gave rise to a loss of somatomedin activity in serum. The loss of somatomedin activity was due to the presence of inhibitors associated with serum proteins having mol wts of less than 1, 1-10, 30-50, and 300 K. Whereas less than 1, 1-10, and 30-50 kilodalton fractions were not inhibitory in control and insulin-treated animals, greater than 300 kilodalton fraction was inhibitory in control and insulin-treated animals; the inhibitory activity of this fraction in diabetic animals was significantly greater than that in controls and insulin-treated animals. The appearance of these inhibitors in diabetic animals was accompanied by reduced skeletal growth. Treatment of diabetic animals with insulin abolished the somatomedin-inhibitory activity of serum and corrected the skeletal growth deficit. Serum inhibitors of somatomedin may, therefore, be involved in the causation of some of the complications of diabetes, including impaired skeletal growth.

Animals↗
PubMed1987

Effects of high dietary sulphur on enzyme activities, selenium concentrations and body weights of cattle.

This study was designed to assess the effects of a moderate increase in dietary sulphur (S) in cattle. Twelve animals were initially fed a basal concentrate (S = 0.2%) and then divided into two groups; one fed basal and the other high S (S = 0.75%) concentrates. Health, body weight gains, and activities of erythrocyte enzymes-glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), glucose-6-phosphate dehydrogenase (G6PD), acetylcholinesterase (AChE), plasma- asparate aminotransferase (AST), and whole blood concentrations of selenium (Se) were monitored at various stages of the study. Marked increases in the activities of GSH-Px, SOD and G6PD from the pretrial values were observed upon initial feeding of basal concentrate diet. Sex related differences were not evident in enzyme activities and Se concentrations of the blood. A high linear correlation (r = 0.92) between averages of GSH-Px activity and Se concentration of blood was observed in both sexes. Increasing the amount of S in the concentrate diet (from 0.2 to 0.75%) did not produce any statistically significant change in enzyme activities and Se concentrations, body weight gains, and health of the cattle during the 85 days feeding period. The results indicate that a moderate increase in the dietary S would not impair Se and copper status or cause related disorders in cattle.

Acetylcholinesterase↗
PubMed1987

Specific skin ulcers in Hodgkin's disease.

A young man with Hodgkin's disease who experienced specific cutaneous ulcers over the scalp during treatment is described. The relation of such ulcers to the disease's progress is discussed.

Adult↗
PubMed1986

Evolution of cell and chromosome structure in eukaryote.

The analysis of the data so far available indicates that eukaryotic chromosome with splicing characteristics appeared quite early in evolution possibly parallel and not sequential to the prokaryotic system. The endosymbiotic origin of the eukaryotic cell involved a primitive undifferentiated unicellular eukaryote and a photosynthetic or non-photosynthetic microbe. Certain regulatory genes of extra-cellular organelles were transferred later through molecular hybridization to the nucleus. The evolution of multicellularity and sexual reproduction led to the origin of innumerable eukaryotic forms in the late precambrian period. This new concept of the author can account for the evolution of complex eukaryotic chromosome and harmonious functioning of extra-cellular organelles with the nucleus. The concept also explains the sudden spurt of innumerable eukaryotic fossils at the early palaeozoic era.

Animals↗
PubMed1986

Palatal mucosa under dentures: a qualitative histologic and histochemical analysis.

These histologic observations of the epithelium and connective tissue are in close agreement with a host of earlier workers. The striking feature is an increase in thickness of epithelium due to an increase in constituent cell layers, but a decrease in keratinization, with keratin mainly of the parakeratinized variety. There is a definite reduction of collagen fiber network in regions of stress where the fibers present an irregular arrangement in contrast to the normal wavy pattern. Marked chronic inflammatory exudate is also seen. Histochemical investigation of the connective tissue under dentures revealed the presence of a highly elastic and resistant oxytalan fiber network, especially in regions that showed a reduction in collagen fibers. Thus the connective tissue response under dentures is in sharp contrast to what is expected. This abnormal behavior of the connective tissue is probably a reaction to the changes in epithelium. As a result of reduction in keratinization, a highly resistant and protective layer, the connective tissue exhibits altered metabolism and function. We hypothesize that connective tissue takes up a more dominant role of protection and absorption of stress, a role hitherto fulfilled by the epithelium. Thus stresses exerted by dentures on connective tissues are prevented from reaching the bone where they could cause resorption. We therefore feel that denture wear not only results in change within the epithelium, but in an equally significant reaction of the connective tissue. This reaction results in the appearance of a highly resistant and elastic oxytalan fiber system, which assists the connective tissue to react successfully to the stresses exerted on it.

Adult↗
PubMed1986

The effect of continuous subcutaneous insulin infusion therapy on morphological and biochemical abnormalities of peripheral nerves in experimental diabetes.

Diabetes mellitus was induced in rats by the administration of streptozotocin and observations have been made over a period of 2 months in 3 groups of animals: controls, untreated diabetics and diabetics treated with continuous subcutaneous insulin infusion (CSII) therapy, using a 14-day Alzet osmotic minipump. Optimal control of day-to-day and 24-h blood glucose levels was achieved in diabetic animals treated with CSII. Body weight and skeletal growth, assessed by measurements of tibial length, were decreased in untreated diabetic rats and were normalized by insulin treatment. The concentrations of glucose, sorbitol and fructose in the nerves of diabetic animals were significantly increased and that of myoinositol significantly decreased; CSII therapy normalized these levels to those of age-matched controls. External myelinated fibre diameter in the tibial nerve was significantly less in untreated diabetic rats as compared with age-matched controls. In the insulin-treated group, fibre diameter significantly increased as compared with untreated diabetics and there was no significant difference between insulin-treated and control animals. Teased fibre preparations from the tibial nerve revealed very few abnormal fibres in all the three groups and no significant difference was detected between any of the groups. Continuous subcutaneous insulin infusion therapy, therefore, corrected biochemical abnormalities and also normalized myelinated fibre diameter in the peripheral nerves of experimental diabetic animals. The paradoxical excess of axonal degeneration that has been reported with conventional insulin treatment was not observed.

Animals↗
PubMed1986

Oral cysticercosis.

A 35-year-old Indian male with nodules in the tongue, lower lip and subcutaneous tissues and convulsions of recent onset is presented. Surgical excision of the nodules confirmed the clinical diagnosis of cysticercosis and relieved the lingual discomfort. This is the 26th case of oral cysticercosis being reported.

Adult↗