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Biomedical subjects

K Sankaran

Publications and source records attributed to K Sankaran.

At least 109 records · Page 6Linked to original sources
PubMed1978

Heat-stable low molecular weight form of phosphodiesterases from bovine pineal gland.

The 105,000 X g supernatant fraction of bovine pineal gland contains a phosphodiesterase activity that hydrolyzes both cyclic AMP and cyclic GMP. The rate of hydrolysis is 4-5 times greater with cyclic GMP as substrate than with cyclic AMP. Chromatography of supernatant fraction on Sephadex G-150 resolves phosphodiesterase activity into two fractions designated PDE I and PDE II. These are distinguishable on the basis of their molecular size, substrate specificity, and kinetic parameters. PDE I hydrolyzes cyclic GMP at a faster rate than cyclic AMP and has a molecular weight of 163,000. PDE II appears to be a smaller protein with a molecular weight of 24,400 and is specific for cyclic AMP. PDE I has apparent Km values of 83 and 53 micron for cyclic AMP and cyclic GMP, respectively, whereas PDE II exhibits an apparent Km value of 330 micron for cyclic AMP. With subsaturating concentrations of cyclic AMP as substrate, the phosphodiesterase activity of PDE I is inhibited by the addition of cyclic GMP. However, PDE II activity remains unaffected by cyclic GMP even at concentrations up to 125 micron. PDE II appears to be thermostable, losing only 20% of its activity on heating at 80 degrees for 2 min. Similar treatment completely abolishes the enzyme activity of PDE I.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1977

Maternal and neonatal effects of methoxyflurane, nitrous oxide and lumbar epidural anaesthesia for Caesarean section.

General anaesthetic techniques continue to be used for Caesarean section despite the possible increased incidence of foetal acidosis and neonatal depression. Two techniques of general anaesthesia (methoxyflurane-oxygen and nitrous oxide-oxygen) and lumbar epidural anaesthesia were compared in 37 patients under-going elective Caesarean section. Apgar scores at birth were similar in all three groups. Neurophysiological testing of the neonates at six hours and twenty-four hours of age revealed a superiority for the methoxyflurane-oxygen and lumbar epidural techniques, although the babies in the epidural group tended to be hypotonic. Cord blood gas analysis showed the babies in the methoxyflurane group to have a higher PaO2 with less metabolic acidosis than the babies from the other two groups. The maternal effects of the three anaesthetic techniques were similar, with only a small rise in serum fluroide levels noted in the methoxyflurane group.

Anesthesia, Epidural↗
PubMed1977

Lenticonus in Alport's syndrome. A family study.

A South Indian family with three well documented cases of Alport's syndrome with anterior lenticonus are reported. Clinical features of the syndrome including ocular and laboratory findings have been presented and discussed. Macular pigmentation, 5 cases, subcapsular opacity and nephrotic syndrome, one case each, observed in the present series are of great interest and are quite rare in patients with Alport's syndrome. Critical analysis of the family pedigree revealed autosomal dominance with incomplete penetrance as the possible mode of genetic transmission of the disease.

Adolescent↗
PubMed1976

Protein kinases from liver mitochondria of tumour-bearing rats.

The mitochondria of liver of Yoshida ascites tumour-bearing rats contained two forms of protein kinase distinguishable on the basis of their kinetic properties, substrate specificity and responses to cyclic adenosine 3',5'-monophosphate (cAMP). One of these (kinase I) was activated 2-3 fold by cAMP while the other form (kinase II) was insensitive to the action of cAMP. Kinase I which was selective towards histone F1 as substrate was obtained as a homogeneous preparation and was observed to have a molecular weight of 170 000 by Sephadex G-150 gel filtration. Protein kinase II appeared to be a smaller protein with molecular weight of 54 000 and was specific towards acidic proteins namely casein and phosvitin. Protein kinases isolated from liver mitochondria of normal rats showed variations in respect to elution profile of DEAE-cellulose and electrophoretic mobility. The preparation corresponding to kinase I did not show stimulatory responses to cAMP.

Animals↗