Biomedical subjects
Publications and source records attributed to L Gustavsson.
An abnormal acidic phospholipid was found in high concentration in kidney and brain, and also in other organs of rats exposed to ethanol by i.p. injection or by a liquid diet. The compound could be identified as phosphatidylethanol. Phosphatidylethanol is probably formed in cell membranes by a phospholipase D-catalyzed transphosphatidylation reaction.
Low-degree haemolysis, seen in alcoholics after debauche, may originate from abnormal lipid and fatty acid composition of the erythrocyte membranes. This hypothesis was tested on 13 chronic alcoholics without signs of severe liver disease after an abuse period of more than 7 days. Erythrocytes were analysed at admittance and during withdrawal after 1 and 2 weeks. In order to evaluate the usefulness of whole erythrocytes instead of purified plasma membranes for these analyses a comparison was made. No differences were found with regard to the fatty acid patterns. Reference values of the fatty acid composition of phosphatidylcholine and phosphatidylethanolamine from erythrocytes were also established in control persons. The fatty acid composition of both phosphatidylcholine and phosphatidylethanolamine in the erythrocytes was significantly different from controls at admission. Polyunsaturated fatty acids were decreased and saturated and monounsaturated fatty acids were increased. In phosphatidylcholine, the proportions of the fatty acids of the linoleic acid series were 24% decreased at admittance and 2 weeks later still 19% lower than in controls. The abnormal fatty acid patterns of erythrocytes correlated with similar aberrations in blood plasma phospholipids at admittance. The pathological levels of fatty acids in erythrocytes normalized slower in erythrocytes than in plasma. We conclude that the abnormal fatty acid composition is induced during erythropoiesis.
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A retrospective study on reproductive hazards was performed among 542 employees at Swedish power plants. Questionnaires were answered by 89% of the employees. Data on pregnancies were checked by studying hospital case records. There was a statistically significant, decreased frequency of "normal" pregnancy outcome, almost exclusively due to an increased frequency of congenital malformations, when the father was a high-voltage switchyard worker. The differences in pregnancy outcome could not be explained by any of the confounding factors analyzed. The total number of children with malformations (26) and the total number of pregnancies in this study, however, were very small.
Fibers from the m. vastus lateralis of 10 middle-aged men were classified at ultrastructural level according to the appearance of the sarcomeric M-band. The Z-band widths had a two-peak distribution. One peak was due to type 1 fibers (mean 125 +/- 11 nm), the other to type 2 fibers. This latter could be separated into type 2A (101 +/- 9 nm) and type 2B (86 +/- 8 nm). About 83% of the fibers would have been correctly classified on the basis of the Z-band width alone. Mitochondrial volumes differed (type 1 5.6 +/- 0.8, 2A 4.0 +/- 0.8, and 2B 2.8 +/- 0.8%). However, only one third (37%) of the fibers would have been correctly classified if sorted according to this parameter. Mitochondrial volumes in the different fibers were correlated to mitochondrial enzymes, while fiber sizes and numbers were correlated to cytoplasmic variables. The correlations appeared mainly after a training program, suggesting that the relationships between structural and functional parameters are more obvious after adaptation to higher functional demands.
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The lipid composition was analysed in forebrain subcellular fractions from rats treated with ethanol for three weeks and control rats. Increased proportions of oleic acid and a decrease in palmitic acid were consistently found in total glycerophospholipid fractions after ethanol exposure. The fatty acid compositions of individual phospholipids were also significantly changed. The proportion of docosahexaenoic acid was decreased in brain phosphatidylserine. In contrast to the decrease in the degree of unsaturation in phosphatidylserine, there was an opposite change in phosphatidylcholine wherein the degree of unsaturation was increased. No changes were produced in total cholesterol or phospholipid concentrations. These results point to a high degree of complexity of the mechanisms behind ethanol-induced changes in membrane lipid composition. The decrease in unsaturation in phosphatidylserine is probably an adaptive effect in order to counteract the fluidizing effect of ethanol. There are two possible explanations for the increase in unsaturation in brain phosphatidylcholine. The change may be due to adaptation to other biophysical effects, e.g., expansion of the membrane surface or be secondary to a change in liver lipid metabolism.