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Biomedical subjects

L A Ehrhart

Publications and source records attributed to L A Ehrhart.

9 recordsLinked to original sources
PubMed1977

Studies on a beta-migrating high density lipoprotein.

An unusual serum lipoprotein (Lp) profile was detected in a Japanese family. A double beta-Lp was observed when serum was subjected to polyacrylamide gel electrophoresis. The slower migrating beta-Lp was identified as a subfraction of high density lipoprotein (HDL). It was present in the d 1.063--1.21 fraction, migrated to the position designated as the midband L.1 (sinking pre-beta-lipoprotein) by Mead, M.G. and Dangerfield, W.G. (1974) (Clin. Chim. Acta 51, 173--182) [1], and reacted against human anti-beta-Lp antiserum. This lipoprotein contained greater amounts of triglyceride than the usual beta-lipoprotein and could not be clearly detected by paper electrophoresis. Individuals exhibiting this high density midband lipoprotein appeared to be heterozygous for an autosomal dominant gene. Although other reports have indicated the possibility of a positive association between the occurrence of serum lipoproteins with unusual eletrophoretic mobility and premature ischemic heart disease, no such correlation was demonstrable in these subjects.

Adolescent↗
PubMed1977

Enhanced synthesis and accumulation of collagen in cholesterol-aggravated pigeon atherosclerosis.

Atherosclerotic segments of pigeon aorta synthesized collagen at four times the rate found in normal aorta (Athero = 2071 +/- 1339 ng/g/h; Control = 497 +/- 192 ng/g/h; P less than 0.025). Similar results were obtained when synthesis was expressed per mg DNA. Elevation in collagen synthesis was relatively specific, collagen accounting for 4% of total protein synthesis in lesion-free aorta and 11.5% in atherosclerotic aorta. Substantial increases in total collagen were observed in atherosclerotic aortas (Athero = 9.9 +/- 3.1 mg/aorta; Control = 6.0 +/- 1.3 mg/aorta; P less than 0.05). Ultrastructural studies revealed the accumulation of large amounts of dense fibrillar collagen in the sub-endothelial region of the plaque. Plaque cells contained multiple vacuoles, an extensive rought endoplasmic reticulum and many mitochondria, suggesting active protein synthesis. It is concluded that increased collagen biosynthesis and deposition is an important metabolic derangement in lipid-rich atherosclerotic lesions whihc promotes their gradual conversion to fibrous plaques.

Animals↗
PubMed1977

Stimulation of aortic protein synthesis in experimental rabbit atherosclerosis.

Collagen, elastin and non-fibrous protein synthesis were measured in the aortas of male New Zealand white rabbits fed a diet containing 2% cholesterol for 140 or 180 days. At these time periods increases in aortic cholesterol and cholesteryl esters were evident. The atherosclerotic lesions induced were predominantly of the foam cell type although some areas of early fibrous lesion formation were noted. These changes in lipid concentration and arterial morphology were accompanied by a significant increase in collagen synthesis as determined by the formation of [14C]hydroxyproline. This increase, however, was not confined specifically to collagen since both elastin and non-collagenous proteins were also being synthesized at a higher rate. The two-fold increase in the rates of both fibrous and non-fibrous protein synthesis may in part be a consequence of marked intimal hyperplasia necessitating a general increase in protein synthesis.

Animals↗
PubMed1975

Metabolic interactions among polyunsaturated fatty acids in response to an atherogenic diet.

The distribution of fatty acids in hepatic lipids of dogs fed a diet containing hydrogenated coconut oil as the only source of lipid, changed in the manner characteristic of essential fatty acid deficiency. Cholesterol supplementation of this diet accentuated these changes resulting in further increases in oleic and eicosatrienoic acids and decreases in the distribution of linoleic and arachidonic acids. Two eicosatrienoic acid isomers, 20:3 omega9, derived from oleic acid and 20:3 omega6, an intermediate in the biosynthesis of arachidonic acid from linoleic acid, were identified. The increase of the 20:3 omega6 isomer was found, somewhat unexpectedly, to be greater than that of 20:3 omega9, the isomer normally associated with EFA defiency. The increase in 20:3 omega6 was probably due in part, but not completely, to competitive inhibition by the increased concentration of 20:3 omega9 on the desaturation reaction whereby 20:3 omega6 is converted to arachidonic acid.

Animals↗
PubMed1975

Effects of hyperlipoproteinemic serum and exogenous proline concentration on collagen synthesis by isolated rabbit aortas.

Collagen synthesis was measured in segments of normal rabbit aorta, incubated in vitro, by monitoring the formation of peptidyl-14C-hydroxyproline from [U-14C]-L-proline added to the incubation medium. The effect of hyperlipoproteinemic rabbit serum on the rate of collagen synthesis was compared with the effect of normal rabbit serum. No differences in the rates of synthesis were detected between the two batches of serum, despite a 60-fold difference in serum cholesterol concentration. Increases in free proline concentration in the incubation medium resulted in changes in proline flux between medium and tissue pools of free proline, but medium proline concentration had no effect on the rate of collagen synthesis.

Animals↗