Serum selenium concentration related to myocardial infarction and fatty acid content of serum lipids.

A longitudinal case-control study of 33 patients with one or more risk factors for coronary heart disease and 64 controls showed that the serum selenium concentration (range 0.63-1.33 mumol/l (50-105 micrograms/l] was not associated with development of clinical manifestations of coronary heart disease during a follow up of five to seven years. The content of polyunsaturated fatty acids, especially eicosapentaenoic acid, in serum cholesterol esters and phospholipids was positively correlated with selenium concentration. As a low content of polyunsaturated fatty acids in serum lipids was an independent risk factor for coronary heart disease in these subjects it may be hypothesised that the high coronary risk in subjects with a very low serum selenium concentration (less than 0.57 mumol/l (less than 45 micrograms/l] might be due not to selenium deficiency but to the coexisting low concentrations of polyunsaturated fatty acids in serum.     

Fatty-acid desaturation and microsomal lipid fatty-acid composition in experimental hyperthyroidism.

We have studied the influence of experimental hyperthyroidism in the rat on the synthesis of unsaturated fatty acids and on liver microsomal lipid fatty-acid composition. Tri-iodothyronine treatment (25 micrograms/100 g body weight) daily for 3 weeks caused no significant changes in delta 9 (stearate) desaturation but a 24% decrease in delta 6 (linoleate) desaturation. Much larger doses of tri-iodothyronine increased delta 9 desaturation. Liver microsomal fatty-acid composition in hyperthyroidism is altered with significantly increased proportions of stearate and arachidonate and decreased proportions of palmitate, palmitoleate, linoleate (C18:2) and eicosa-8,11,14-trienoate (C20:3). These changes, other than the decreases proportion of C20:3 fatty acid, which may be due to the diminished delta 6 desaturase activity, cannot be attributed to changes in fatty-acid desaturation. Most of these changes were also found to be due not simply to the decreased weight gain or the increased food intake of the hyperthyroid animals. Only the decreased C18:2 fatty-acid proportions could be mimicked by restricting food intake of control animals and none of the changes were prevented by restricting food intake of hyperthyroid animals. Thus most of the changes in microsomal lipid fatty-acid composition are likely to be due to a thyroid hormone effect on peripheral lipid mobilization or lipid degradation.     

Radioimmunoassay of serum myoglobin in screening for acute myocardial infarction.

Over an 8-month period 289 patients consecutively admitted to a coronary care unit were studied to assess the value of serum myoglobin determinations by radioimmunoassay in screening for acute myocardial infarction. Of the 289 patients 127 (44%) had an infarction. It was found that when blood sampling was done within 5 to 15 hours after the onset of chest pain this assay had a sensitivity, specificity, and positive and negative predictive values of more than 97%. In this study healthy young adults had a mean serum myoglobin level of 37 +/- 11 (standard deviation) ng/ml, and values above 80 ng/ml were considered positive for acute myocardial infarction. False-positive results can be due to stock, vigorous exercise, skeletal muscle damage and several renal failure, but, except for the last one, these conditions also caused an increase in the serum level of the creatine kinase isoenzyme CK-MB.     

Blood serum concentration of lipids and lipoproteins and body composition

The purpose of this study is the analysis of the relationship of blood serum apolipoprotein E (apoE), total cholesterol (TC), triglycerides (TG) and high-density and low-density lipoproteins (HDL, LDL), with body mass index (BMI), relative body surface area (RBSA) and body muscle (BM) and body fat (BF). The subjects are males and females aged 14-16 (adolescent age group 1: n1M = 141, n1F = 151) and 18-25 (young adult group 2, n2M = 16, n2F = 46). Significant correlations of serum TG and HDL with somatometric indicators were not observed. In the female samples, TC content directly correlates (p < 0.05) with BF (r1 = 0.164; r2 = 0.418) and negatively correlates with BM (r1 = -0.165; r2 = -0.352). The blood serum concentration of apoE is significantly correlated with body composition in adolescent females (for BF r1 = -0.168; for BM r1 = 0.266; p < 0.05); in males 14-16 years old, the both correlations have a significance level p < 0.06. In young adult females TC and LDL content negatively correlates with RBSA (r2 = -0.386 and -0.377 respectively; p < 0.05) and positively correlates with BMI (r2 = 0.413 and 0.415 respectively; p < 0.05). Adolescent females and young adult females have opposite relationships between FC and apoE concentration. In females 14-15 years old apoE concentration decreases as FC increases. In females 16-17 the correlation disappears, and in older females apoE concentration and FC increase together.     

EPR study of serum ceruloplasmin and iron transferrin in myocardial infarction.

Electron paramagnetic resonance (EPR) analysis of frozen serum from myocardial infarction patients has been conducted. Signal at g=4.3 was found definitively attributable to iron(III)-transferrin complex. Imcrease of serum ceruloplasmin as compared to normal was confirmed, with a concomitant decrease of iron-transferrin content. A mechanism for such correlated variation is hypothesized.     

Fatty acid composition of serum lipids in bilharzial hepatic fibrosis and chronic active hepatitis.

The fatty acid pattern of blood serum lipids was examined by gas liquid-chromatography in 30 cases with bilharzial hepatic fibrosis, 11 cases with chronic active hepatitis accompanied by jaundice, and 28 healthy individuals as a comparison group of the same socioeconomic class of patients. In addition, the fatty acid patterns of the three major serum lipid classes, namely: cholesterol ester, phospholipids and triglycerides, were also investigated in seven cases of each group by gas liquid chromatography. The most remarkable differences were: a depression of the essential fatty acid level (linoleic and arachidonic) in both groups of patients together with a concomitant elevation of oleic acid in the bilharzial group and an elevation of oleic, palmitic, palmitoleic acids in the chronic active hepatitis group. The depression of linoleic and arachidonic acids was explained by the low fat diet intake, malnutrition, and the malabsorption factors which were frequent in all the patients studied. The elevation of monoethenoid acids was attributed to the decrease in the ability of the liver to desaturate the endogenous saturated and monounsaturated acids to polyunsaturated ones.     

Changes in fatty acid compositions of myocardial lipids in rats with heart failure following myocardial infarction

Changes in fatty acid composition of myocardial lipids were examined in rats with heart failure following myocardial infarction. Left ventricular systolic pressure (LVSP) was decreased and left ventricular end-diastolic pressure (LVEDP) was elevated 24 h, 1 and 12 weeks after left coronary artery ligation (CAL), suggesting the development of heart failure at these periods in this model. Hearts were isolated 24 h, 1 week and 12 weeks after the operation. Myocardial lipids in the infarcted scar tissue, non-infarcted remaining left ventricle including interseptum and right ventricle were separated into phospholipid (PL), triacylglycerol (TG), diacylglycerol (DAG) and free fatty acid (FFA) fractions. In the scar tissue PL content markedly decreased whereas TG, DAG and FFA contents increased 24 h after CAL. Despite a marked decrease in constituted fatty acids of PL fraction in the scar tissue the percentage of arachidonic acid in PL was elevated 12 weeks after CAL, suggesting that release of arachidonic acid during PL degradation was suppressed. In the non-infarcted viable left ventricle PL content remained unchanged throughout the experiment whereas TG, DAG and FFA contents were elevated 24 h after CAL. Despite no changes in PL and other lipid contents in the non-infarcted tissue the percentage of linoleic acid in PL was reduced and that of docosahexaenoic acid in PL was elevated 12 weeks after CAL. Our findings showed that myocardial lipid composition of the non-infarcted left ventricle was altered only in an early stage of the development of heart failure and fatty acid compositions of PL was exchanged in a late stage of the development of heart failure. The exchange may be related to cardiac dysfunction or myocardial remodelling in the rat with heart failure.