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Biomedical subjects

A K Sharma

Publications and source records attributed to A K Sharma.

At least 433 records · Page 24Linked to original sources
PubMed1979

Estimation of daily sperm production rate (DSPR) by quantitative testicular histology in Buffalo-bulls (Bubalus bubalis).

Testes and epididymides from six sexually rested buffalo-bulls were removed during breeding season. The average weight of the testicular parenchyma was 138.62 g, of which the tunica albuginea accounted for 8.45 g. Relative distribution of spermatozoa in caput, corpus, and cauda epididymides averaged 5.42, 0.75, and 11.45 billion, respectively. Total epididymal sperm reserve per bull was 36.2 billion. The efficiency of sperm production was quite uniform and averaged 14.5 x 10(6) sperm per gram of testicular parenchyma per day with a mean of 2.02 x 10(9) sperm per testis. Thus a typical buffalo-bull produces about 4 x 10(9) sperm daily during breeding season.

Animals↗
PubMed1979

Trypsin-orcein banding in plant chromosomes.

A convenient and quick method using trypsin-orcein for banding plant chromosomes (O-banding) is suggested. The technique is directly applicable to meristematic tissues (e.g. root tips) and involves the treatment of root tips with 1-2% solution of trypsin either in buffer or in 0.5 N HCl for 5-10 minutes at 37 C or for 30-60 minutes near 0 C followed by staining with 1.5% acetic orcein: 1 N HCl (19:1). Dark staining bands are reproducible and species specific. These bands possibly represent specific DNA-protein-dye interaction.

Chromosome Banding↗
PubMed1979

Concanavalin A induced suppressor activity in human leprosy.

Peripheral blood lymphocytes from nine normal subjects and 40 patients with leprosy were pretreated in vitro with Concanavalin A (Con A). Cells from normal subjects pretreated for 24 hours showed consistent and effective generation of suppressive activity which inhibited mitogen induced transformation of autologous lymphocytes. Prolongation of Con A pretreatment to 40 hours resulted in maximal suppressive activity. Tuberculoid leprosy patients had lymphocytes in their blood which on 24 hour pretreatment with Con A exerted suppressive effects markedly greater than the maximal suppression noted with 40 hour pretreated normal lymphocytes. In contrast, untreated patients with polar lepromatous leprosy showed a decrease in suppressive activity which could not be altered by prolongation of Con A pretreatment: the loss of suppressive activity noted in this form of leprosy was restored during erythema nodosum leprosum.

Concanavalin A↗
PubMed1978

Influence of dietary myoinositol on nerve conduction and inositol phospholipids in normal and diabetic rats.

Observations have been made on motor conduction velocity in the tibial nerve of rats given 35% myoinositol in the diet. Comparison between the values before and with up to nine weeks of dosing revealed no alteration in conduction velocity. In such animals, the free myoinositol content in the sciatic nerve was increased; there was no detectable alteration in the lipid inositol concentration. In a second series of experiments, tibial motor nerve conduction velocity in rats with streptozotocin-induced diabetes was compared with conduction velocity in diabetic animals given 1% supplementary dietary myoinositol, and with a control group of nondiabetic rats. Conduction velocity was reduced in the diabetic animals, but no influence from the added dietary myoinositol was detected. No statistically significantly difference in sciatic nerve myoinositol was demonstrated, but the sorbitol and fructose concentrations were increased. Those animals fed the myoinositol supplement had a significantly lower lipid inositol content. The significance of these findings is discussed.

Animals↗
PubMed1977

Peripheral nerve fiber size in experimental diabetes.

Serial morphometric observations were made on the tibial nerves of mature rats before and five weeks after the induction of diabetes by streptozotocin. Maximum and average myelinated fiber diameter did alter, neither did the relationship between myelin sheath thickness and axon circumference. This confirms previous observations suggesting that the reduced nerve conduction velocity that is known to occur in experimental diabetes is likely to depend on metabolic alterations rather than on structural changes.

Animals↗
PubMed1977

Circulating T-cell numbers and their mitogenic potential in leprosy--correlation with mycobacterial load.

The effect of treatment and mycobacterial load on circulating T-cell numbers and their functional ability was investigated in forty-one patients with leprosy. Both early binding T cells and their responses to phytohaemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM) were profoundly and uniformly depressed in untreated, and partially treated, bacilleferous lepromatous leprosy (LL) patients as compared with normal subjects and tuberculoid patients. On elimination of mycobacteria, subsequent to chemotherapy, LL patients regain normality in T-cell numbers and their functions. On the other hand, the specific response of lymphocytes to M. leprae did not alter with decrease in mycobacterial load. It appears that the decrease in T-cell numbers and the deficit in their mitogenic potential is a secondary consequence of disease and is related to the antigenic load in patients with lepromatous leprosy.

Antigens, Bacterial↗
PubMed1976

Peripheral nerve abnormalities related to galactose administration in rats.

Electrophysiological, biochemical, and morphometric observations were made on the peripheral nerves of rats after galactose feeding. Motor nerve conduction velocity was found to be reduced. This was associated with an accumulation of galactitol in the peripheral nerves and a diminution in their myoinositol content. An increased water content and fascicular area, taken in conjunction with a probable increase in the area of the endoneurial spaces, indicated overhydration of the peripheral nerves. Morphometric observations on the myelinated fibre population in the tibial nerve showed no loss of fibres and although both the maximal and the average diameter of the myelinated fibres was slightly less than in age-matched controls, this was insufficient to explain the reduction in conduction velocity. Segmental demyelination was not detected and the relationship between myelin thickness and axon circumference was not altered. Electron microscope observations revealed no ultrastructural changes in the myelinated fibres and, in particular, no abnormalities at the nodes of Ranvier or indication of abnormal hydration of the Schwann cells. The relevance of these findings to the peripheral nerve changes in human and experimental diabetes is discussed.

Animals↗
PubMed1975

Peripheral nerve regeneration in experimental diabetes.

Observations have been made on the regeneration of myelinated fibres in the sural nerve of streptozotocin-induced diabetic rats and age-matched non-diabetic control animals at 3, 6 and 18 weeks after a localized crush lesion. Morphometric studies on the regenerated fibres revealed no differences in the total fibre count, size-frequency distribution or average diameter at 18 weeks after injury. The degree of myelination was assessed by relating the number of myelin lamellae to axon circumference. The relationship was found to be approximately linear. There was a possible slight lag in myelination at 3 weeks after injury in the diabetic animal, but no difference was detectable at 6 and 18 weeks after injury.

Animals↗