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Biomedical subjects

A K Reddy

Publications and source records attributed to A K Reddy.

28 records · Page 2Linked to original sources
PubMed1987

Percutaneous absorption, metabolism, and hemolytic activity of n-butoxyethanol.

A series of studies was conducted to examine the percutaneous absorption, distribution, excretion, and hemolytic activity of n-butoxyethanol (BE). Rats receiving a subcutaneous dose of 14C-labeled BE excreted the radioactivity in the urine (79%), expired air (10%), and feces (0.5%) within 72 hr. Of the organs analyzed, thymus and spleen showed elevated specific radioactivities as compared with blood. A percutaneous application of BE on rats, under nonocclusive conditions, showed 25-29% absorption within 48 hr. Peak blood levels of BE occurred at 2 hr after application; butoxyacetic acid (BAA) was found to be the major metabolite. Comparison of in vitro skin penetration data showed the following absorption pattern of BE: hairless rat much greater than pig greater than human skin. Hemolysis and associated hematological changes were noted in the rats which received single dermal applications of 260-500 mg/kg of BE. In vitro, BAA showed markedly greater hemolytic ability on rat erythrocytes than did BE. Human erythrocytes showed no hemolysis when incubated with BE or BAA at concentrations that are hemolytic to rat erythrocytes. An intravenous dose of 62.5 mg/kg of BE does not result in hemolysis or hemoglobinuria in the rat. The rat may be an animal model with increased susceptibility to the effects of BE compared with humans because of its rapid percutaneous absorptive ability and its greater hemolytic sensitivity.

Administration, Topical↗
PubMed1986

Selected pulmonary biochemical and hematological changes produced by prolonged hypoxia in the rat.

Rats were exposed to 12% O2 (1 atm) for 48 hr, then 10% O2 for the duration of the exposures. Significant elevations in enzymes of the glutathione peroxidase system were found in the lungs of rats killed 3.5, 7.5, and 12.5 days of exposure compared to air-breathing controls. Superoxide dismutase was also elevated after hypoxia but nonsignificantly. Animals killed 12.5 days after exposures exhibited 75% (P less than 0.05) more thiobarbituric acid reactive products in their lungs compared to controls. These results along with significant increases of lung lipid peroxidation and in an augmentation of protective antiperoxidative lung defense capabilities. Hypoxia also resulted in enzyme elevations of lung phosphofructokinase and pyruvate kinase, which may indicate an adaptive increase in lung glycolytic capabilities which would be helpful in maintaining lung tissue energy requirements during hypoxia. In addition, it was confirmed that red blood cell count, hemoglobin and hematocrit values increased after prolonged hypoxia. The results of this study might also reflect enzyme elevation/induction due to cellular reparative-proliferative processes following hypoxia.

Animals↗
PubMed1986

Malignant fibrous histiocytoma arising from the meninges of the posterior fossa.

A case of malignant fibrous histiocytoma presenting as a cerebellar mass in a young man is described. The tumor was found to be arising from the dura mater and infiltrating the cerebellum. The ultrastructural and immunocytochemical studies confirmed the mesenchymal origin of the neoplasm. Focal reactive astrocytomalike areas were observed in the midst of this tumor.

Adult↗
PubMed1984

Intraspinal arachnoid cysts.

Arachnoid cysts are rare lesions responsible for spinal cord compression. Five cases of congenital intraspinal arachnoid cysts are reported. Three cases of thoracic and two cases of thoracolumbar region were encountered. The clinical presentation was one of progressive spastic paraparesis. The characteristic radiological features are described. Surgery was successful in all cases.

Adolescent↗
PubMedDate not supplied

Application of phonocardiography for detecting hypoxia-induced cardiovascular adaptation in the chicken.

Phonocardiography was evaluated as a noninvasive technique for diagnosis of cardiovascular adaptation and disease in broiler chickens. Heart sounds (HSs) were compared in a fast-growing (FG) commercial broiler line that is highly susceptible to chronic right heart failure resulting from pulmonary hypertension syndrome (PHS) and in a non-selected slow-growing (SG) broiler line that is resistant to PHS. HSs were analyzed in broilers reared in hypobaric hypoxia (HYP) and normobaric (CON) conditions. PHS was induced by a combination of embryonic hypoxia and HYP exposure. HSs were recorded with a microphone placed at the thoracic inlet of each chicken. Electrocardiograms were used to mark the sampling interval for the first, second, and total HS. Digitized HS signals were analyzed for peak frequency, mean peak frequency, and band width. Birds were examined for PHS lesions when 6 wk of age, at the end of each experiment. HSs were compared by line and treatment (Experiment 1) or by treatment and week (Experiment 2). In addition, HS frequencies were analyzed within the HYP treatment group for differences between birds with severe or no gross PHS lesions. HS frequencies generally decreased with age and were also lower in the FG than the SG line. Hypobaric exposure decreased all HS frequencies in the SG line and components of the first HSs in the FG line. The SG line did not develop gross lesions of PHS. In the FG line, significant differences in HS frequencies were observed between HYP and CON groups but not between PHS- and PHS+ broilers. Frequency changes described in humans with PHS were not observed. Further development to maximize the resolution of the HS waveforms and improved matching of the sampling interval to the electrical or hemodynamic output of the chicken heart may allow its use as a diagnostic tool for differentiating broilers with normal cardiac function or physiologic adaptation from those with cardiovascular disease.

Acclimatization↗