Biomedical subjects

K C Hayes

Publications and source records attributed to K C Hayes.

At least 199 records · Page 11Linked to original sources

PubMed1975

Depression of lecithin-cholesterol acyltransferase esterification in vitamin E-deficient monkeys.

Vitamin E deficiency in two species of monkeys (capuchins and cynamolgus) reduced the in vitro cholesterol esterification by plasma lecithin-cholesterol acyltransferase. The reduction was greates in the most deficient species and in animals fed a diet rich in polyunsaturated fat (safflower oil) stripped of vitamin E. The best correlate of total esterification was the plasma concentration of free cholesterol which reflected the degree of hyperlipidemia, found to be greatest in capuchins fed coconut oil. A logical explanation for the decreased LCAT activity in vitamin E deficiency would be peroxidative damage of substrate (the PUFA of lecithin) or of sulfhydryl sited on lecithin-cholesterol acyltransferase itself. However, neither case was fully supported by the data suggesting that additional information concerning the nature of the reaction and the role of vitamin E is required.

Acyltransferases↗

PubMed1975

Cirrhosis of choline deficiency in the Rhesus Monkey. Possible role of dietary cholesterol (38541).

One of five rhesus monkeys fed a diet deficient in choline and protein for 31 mo developed signs of cirrhosis at 26 mo. Five other monkeys were fed the same diet for 14 mo, at which time cholesterol comprising 2% of the diet was added. Three followed a sharp rise in hepatic lipids. One monkey developed marked hypercholesterolemia and showed signs of cirrhosis 2 mo after cholesterol supplementation. The findings indicate that the rhesus monkey is susceptible to choline-deficiency cirrhosis. They suggest that cholestrol supplementation accelerates this process.

Animals↗

PubMed1975

Validation of the dual-isotope plasma ratio technique as a measure of cholesterol absoption in Old and New World monkeys.

Due to the experimental importance of being able to assess cholesterol absorption during the study of atherogenesis in primates, the plasma isotope ratio technique developed for rats by Zilversmit (7) was tested in New and Old World monkeys and compared with a more cumbersome procedure involving fecal collection and analysis. Although fecal analysis demonstrated an unaccountable loss of the intubated isotope, the comparability of the plasma ratios to absorption calculated by other methods suggest that this techique is probably as reliable as any presently available. The loss of isotope may reflect the absence of dietary cholesterol.

Animals↗

PubMed1975

An ultrastructural study of nutritionally induced and reversed retinal degeneration in cats.

Kittens and adult cats fed a semipurified diet containing casein developed a retinal degeneration that initially involved photoreceptor outer segments in the area centralis. By electron microscopy, cone and rod outer segment lamellar discs could be seen to become vesiculated, frayed, disoriented and twisted. Shortening and subsequent disappearance of outer segments was followed by loss of photoreceptor nuclei, primarily in the area centralis but also in the midperipheral retina. The electroretinogram (ERG) indicated progressive reduction in cone and rod amplitudes and a delay in the temporal aspects of the cone response. When dietary casein was replaced by egg albumin in the diets of cats with minimal to moderately advanced degeneration, the degeneration was reversed; rod ERG function and structure returned essentially to normal, whereas some abnormalities of cone outer segment structure and a delay in the temporal aspects of the cone ERG persisted. The data provide strong evidence that dietary casein is a factor in this retinopathy and suggest that an alteration in protein metabolism of the photoreceptor may result from the dietary protein inadequacy.

Animals↗

PubMed1974