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Biomedical subjects

A Shannon

Publications and source records attributed to A Shannon.

28 records · Page 2Linked to original sources
PubMed1966

Effect of sex and gonadal hormones on rat plasma lipids during the development of an essential fatty acid deficiency.

1. Male, female and castrated rats treated with oestradiol (30mug./week) or testosterone (2mg./week) were given an essential fatty acid-deficient diet containing 10% of hydrogenated coconut oil for 9 weeks. The concentrations and fatty acid composition of plasma phospholipids, cholesteryl esters and triglycerides were determined. 2. Between the second and third weeks of the deficiency, concentrations of plasma cholesteryl esters, phospholipids and triglycerides decreased, then remained relatively constant. There were no significant differences between males and females, but oestradiol caused a significant rise in plasma phospholipids and triglycerides as compared with testosterone-treated animals. 3. During the first 2 weeks of the deficiency, linoleic acid in the plasma lipids of all groups decreased to low concentrations and changed very little thereafter. 4. Female rats maintained higher percentages and concentrations of arachidonic acid and stearic acid in plasma phospholipids and arachidonic acid in cholesteryl esters than did males. Males had higher proportions of eicosatrienoic acid and oleic acid. There was no sex difference in the fatty acid composition of plasma triglycerides. 5. Oestradiol-treated rats had concentrations of cholesteryl and phospholipid arachidonate comparable with those of female rats and higher than the testosterone-treated group. Eicosatrienoic acid in the oestradiol-treated rats was high and resembled that of the male rats, apparently because of the higher concentration of plasma phospho lipids in this group. 6. Supplementation of the essential fatty acid-deficient rats with linoleate restored plasma cholesteryl and phospholipid linoleate and arachidonate nearly to normal concentrations in a single day. The increase in arachidonic acid in these fractions was accompanied by a similar quantitative decrease in eicosatrienoic acid. 7. These sex differences appear to be related to the smaller size of the female rat and to a more direct influence of oestradiol on the formation or maintenance of phospholipids rich in arachidonic acid.

Animals↗
PubMedDate not supplied

Growth of coagulase negative staphylococci in peritoneal dialysate fluid. Effect of calcium concentration.

The growth of coagulase negative staphylococci (CNS) in spent and unspent peritoneal dialysate of physiologic (1.25 mmol/l) and standard (1.62 mmol/l) [Ca2++] was studied. Dialysate was prepared by filter sterilization and pH and iCa were measured. Three isolates of CNS grown in unsupplemented Mueller Hinton broth for 18 to 20 hr at 37 degrees C were adjusted to a density of 1.5 x 10(8) CFU/ml. The dialysate (5.4 ml) was inoculated with 0.6 ml of a 10(-4) dilution and then incubated aerobically at 35 degrees C. Plates were made at 0, 6, and 24 hr, and CFU/100 microliters were counted after 24 hr. In a larger study, 10 isolates of CNS were examined. Coagulase negative staphylococcal growth was inhibited by unspent dialysate (P = 0.000; unpaired t-test). Growth was greater in spent physiologic [Ca++] dialysate (iCa -0.76 mmol/l) at 6 hr (P = 0.007) and at 24 hr (P = 0.000) than in standard dialysate (iCa = 0.86 mmol/l) for two of three strains in the pilot study. Similar findings were noted for 4 of 8 strains in the larger study. There was an overall trend for greater growth in physiologic [Ca++] dialysate (P = 0.09). Some strains of CNS grow better in lower [Ca++] dialysate, perhaps representing clinically relevant trophism.

Calcium↗