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Biomedical subjects

A K Saxena

Publications and source records attributed to A K Saxena.

14 recordsLinked to original sources
PubMed1979

Neuroleptic receptors: stereoselectivity for neuroleptic enantiomers.

In order to identify a pair of neuroleptic enantiomers with the highest stereoselective interaction with neuroleptic/dopamine receptors, the effects of eight pairs of neuroleptic enantiomers were tested on the specific binding of 3H-spiperone to crude homogenates of calf caudate nucleus. The ratios of the Ki values were: (+)-butaclamol/(-)-butaclamol = 3000; dexclamol/(-)-analogue = 151; (+)-isobutaclamol/(-)-isobutaclamol = 146; (-)-CTC/(+)-CTC= 109; (-)-centbutindole/(+)-centbutindole = 20; S(+)-octoclothepin/R(-)-octoclothepin = 11. Thus, the neuroleptic receptor is highly stereoselective for the rigid butaclamol derivatives, but much less so for the flexible neuroleptics. The 3H-apomorphine binding site, however, had a stereoselectivity ratio of only 7 for isobutaclamol, further suggesting that the high affinity sites (i.e. nM) for 3H-neuroleptic binding and for 3H-apomorphine binding are different.

Animals↗
PubMed1979

Evaluation of carcinogenic effect of mineral oil used in the processing of jute fibres.

To evaluate the carcinogenic activity of jute-batching oil (JBO), this substance was painted on the skin of ITRC mice up to 300 days. Initially hyper- and parakeratosis of the stratum corneum, acanthosis and spongiosis of the stratum Malpighii, hyperactivity of fibroblasts, and laying down of collagen fibres in the dermis were encountered at 100 days. This was followed by poor hair growth, acne formation and ulceration. As time passed, these animals partially adapted themselves to the oil-painting so that by 200 days hyperkeratosis and parakeratosis of the stratum corneum, as well as acanthosis and spongiosis of the stratum Malpighii, had almost disappeared. The ulcers healed and no more acne was visible; however, the baldness and loss of hair appendages persisted to 300 days. No carcinogenic changes in the skin or in the viscera of these mice were observed. On UV and IR spectroscopy no traces of any polycyclic aromatic hydrocarbons were found in the JBO sample. Mice, on the other hand, when painted with the known carcinogen 3,4 benzpyrene (BP), developed skin tumours, showing that the mice used in this study were not cancer-resistant. Also, when JBO was applied with BP, the time taken for tumour development in mice was shortened by about 4 weeks as compared to another group painted with the same dose of BP alone. This suggests a cancer-promoting activity which needs to be investigated further.

Acne Vulgaris↗
PubMed1978

Histopathological changes induced by quinalphos in the testes and liver of Indian dessert gerbils, Meriones hurrianae (Jerdon).

Single intraperitoneal injection of quinalphos (15 mg/kg body weight) produced several pathological changes in the testes and liver of the Indian desert gerbil, Meriones hurriane (Jerdon). The degenerative changes included testicular atrophy, reduction in tubular size and enlarged interstitium. In the spermatogenic cells, necrosis and karyopycnosis were observed. Hepatic cells revealed cytoplasmolysis, vacuolation and necrosis. The nuclei of the hepatocytes showed karyorrhexis and karyolysis.

Animals↗
PubMed1978

Relationship of plasma lipids to renal function and length of time on maintenance hemodialysis.

Significant hypertriglyceridemia, the most common lipid abnormality in renal failure, first occurs when the creatinine clearance falls to 50 ml/min. The prevalence of hypertriglyceridemia continues to rise as creatinine clearance falls further with the highest rate developing at a creatinine clearance less than 10 ml/min. Hypertriglyceridemia is correlated with plasma glucagon levels but not growth hormone or insulin. Plasma cholesterol values remain normal in the face of deteriorating renal function and show no correlation with any of the hormones measured. Although all three hormones became elevated as renal function diminished, none were directly correlated with glomerular filtration rate. There was a distinct decrease in the prevalence of hyperlipidemia after 5 years of maintenance hemodialysis therapy. Plasma growth hormone and glucagon through an effect on plasma triglyceride and plasma insulin by effecting plasma cholesterol may play a role in this decline of hyperlipidemia with duration of hemodialysis.

Adult↗
PubMed1978

Central adrenoceptors and cholinoceptors in cardiovascular control.

1. In cats anaesthetized with chloralose, adrenoceptor and cholinoceptor agonists and antagonists were localized to the posterior hypothalamus (PH), lateral medullary pressor area (LMPA) and spinal autonomic loci to delineate the role of central cholinoceptors and adrenoceptors in cardiovascular control. 2 All along the neuroaxis, the alpha-adrenoceptors seem to subserve an inhibitory and the beta-adrenoceptors a facilitatory role in cardiovascular control. There appear to be a predominance of alpha-adrenoceptors at the medullary level and beta-adrenoceptors at the hypothalamic level. 3 The nicotinic cholinoceptors at the hypothalamic, medullary and spinal levels were facilitatory, whereas muscarinic cholinoceptors were inhibitory for cardiovascular control. However, muscarinic receptors were undetectable at the posterior hypothalamus. 4 The central cardiovascular effects of nicotine are attributed to nicotinic receptor activation and release of central catecholamines. 5 There appears to be a relationship between central cholinergic and adrenergic mechanisms in cardiovascular control.

Animals↗
PubMed1977

Electrical stimulation in delayed union of long bones.

The role of electricity in the promotion of fracture union of long bones in human beings requires further investigation. An electric stimulator was devised through which 15 microamperemeter current was applied to the fractured long bones of 20 patients with delayed union. The best results were obtained in cases where the negative electrode was introduced at the fracture site and the positive electrode was placed proximal to the fracture area. In 90 per cent of cases treated by different methods in this series, union occurred within an average period of 9 1/4 weeks. The rate of infection following introduction of electrodes for electrical stimulation was 20 per cent.

Electric Conductivity↗