Biomedical subjects

D Sgoutas

Publications and source records attributed to D Sgoutas.

28 records · Page 2Linked to original sources

PubMed1979

Mechanisms of interference of nonesterified fatty acids in radioimmunoassays of steroids.

Addition of nonesterified fatty acids caused an apparent increase in unbound steroid present in supernatants in radioimmunoassays for steroids utilizing dextran-coated charcoal. Nonesterified fatty acid interference occurred at the initial binding interaction between steroid and its antiserum, and also at the step separating bound from unbound steroid. It was determined that nonesterified fatty acids, which had been added to radioimmunoassays, formed micelles and trapped steroids. The extent of the entrapment was inversely related to the number of polar groups in the steroid molecule, that is, hydrophobic steroids more easily interacted with the nonesterified fatty acid micelles. However, if the charcoal concentration were increased, the nonesterified fatty acid effect was eliminated for assays of polar steroids and greatly reduced for non-polar steroid assays.

Binding Sites↗

PubMed1976

In vitro incorporation of isomeric cis-octadecenoic acids by rat liver mitochondria.

The metabolic fate of positional isomers of cis-octadecenoic acids was compared to that of oleic acid, elaidic acid and stearic acid in rat liver mitochondria. The positional isomers as well as elaidic acid and stearic acid were labelled with 3H and they were incubated in pairs with [1-14C]oleic acid. 3H/14C ratios were determined for the administered mixtures and for the isolated lipid classes. The results suggested that all isomers were readily incorporated into the membraneous structure of mitochondria. Those with the double bond in the middle of the acyl chain resembled oleic acid and they were preferentially incorporated in cholesterol esters, triacylglycerols and in the 2-position of triacylglycerols and of phosphatidylcholines. Those with the double bond away from the middle of the chain were metabolically distinct from oleic acid and behaved like trans fatty acids. They were rapidly taken up by mitochondria. They were preferentially incorporated in phospholipids and they occupied the 1-position in phosphatidylcholines and the 1- and 3-positions in triacylglycerols.

Animals↗

PubMed1975

Essential fatty acid deficiency in four adult patients during total parenteral nutrition.

Four undernourished adults (15%-37% below idealll body weight) received fat-free total parenteral nutrition for a period of 6 to 8 weeks. Chemical evidence of essential fatty acid deficiency (triene:tetraene ratio greater than 0.4) appeared in all patients during the first 3 weeks of treatment. Deficiency developed more rapidly in the two patients who were younger (ages 16 and 36) and more severely undernourished (26% and 37% below ideal body weight) than in the two older patients (62 and 76) who were less undernourished (15% and 16% below idea body weight). All patients continued to gain weight and maintain positive nitrogen balance throughout the course of total parenteral nutrition and developing essential fatty acid deficiency. Hepatomegaly and increased serum liver enzyme activities occurred in the two patients with evidence of the most severe essential fatty acid deficiency. Liver biopsy, in the cases with hepatomegaly, showed hepatocytes containing fat and what appeared to be enlarged, spherical mitochondria. There was no cellular infiltrate or significant degree of necrosis. Supplementation with oral linoleic acid (as safflower oil) reversed the essential fatty acid deficiency and the elevation of serum liver enzymes.

Adolescent↗

PubMed1975

Improved radioimmunoassay of plasm cortisol.

We report a simplified radioimmunoassay procedure for determination of plasma cortisol. The method offers the advantage that tracer, antibody, and assay buffer are added in a single step with the use of semi-automated equipment. Thus, critical pipetting procedures are minimized, and assay time is reduced to 4 h. No prior extraction or chromatographic purification of cortisol is required. The procedure is simple, reliable, and accurate. For either between-assay or within-assay determinations, the coefficients of variation are about 6%. Our results compare well with those obtained from a procedure that included extraction and chromatographic purification of cortisol in several plasma samples. Conditions for optimizing the assay are also discussed.

Autoanalysis↗

PubMed1974