[Insulitis--new findings on the role of genetic and external factors]

The autoimmune process focused on B-cells of the islets of Langerhans and leading gradually to their destruction and the development of type I diabetes takes place under the morphological picture of insulitis. The disease affects genetically predisposed individuals. At the end of the eighties knowledge was greatly expanded due to methods of molecular genetics. The majority of authors assumes that in the pathogenesis of insulitis also environmental factors participate. More detailed information is provided on chemical compounds, nutritive substances and viruses.

[Changes in magnesium and ionized calcium serum levels in disorders of glucose tolerance]

In a group of 58 subjects with a strictly defined glucose tolerance (38 normal--nGT, 10 impaired glucose tolerance--pGT, 10 type II diabetics treated by diet) the authors investigated the mutual relationship between changes in the blood sugar level and insulin serum level in relation changes of calcium, ionized calcium, magnesium and total proteins. In addition to expected differences in the native blood sugar level and insulinaemia, the authors found in pGT group in reduction of ionized calcium and magnesium on fasting. In the course of the oGTT in pGT group there is a rise of ionized calcium and magnesium and thus the changes, as compared with the initial value, differ significantly from changes in subjects with a normal glucose tolerance and in type II diabetics. The differences in the pattern total calcium are less marked, the changes of total protein did not differ. Evaluation of correlations revealed a only significant relationship between the change of ionized calcium and blood sugar level after 120 mins, in DM II. The findings suggest a different calcium and magnesium metabolism after a glucose load in subjects with an impaired glucose tolerance. It is not clear whether a cause of the disorder is involved or a possible compensatory mechanism. The clinical impact will have to be examined.

Effect of sleep deprivation on cholesterol metabolism and triglyceridaemia in male volunteers

The effect of 5-day sleep deprivation (SD) on cholesterol metabolism, together with triglyceridaemia, was studied in seven healthy male volunteers. A 3-day control period was followed by 5 days (120 h) complete SD and 4 days recovery. Blood was collected at 9 a.m. and at 9 p.m. Vastus lateralis muscle biopsy was performed during the control period, on the 5th day of SD, and on day 3 of recovery. The value of muscle cholesterol was related to the non-collagen protein content. The plasma triglycerides (TG) varied in a circadian biorhythm, the amplitude of which declined gradually during SD. The morning triglyceridaemia was significantly decreased on days 3-5 of SD (35%-79% of initial values). On days 4 and 5 of SD, plasma cholesterol fell significantly to 78% and 88% of control values, respectively. The ratio of its esterified to unesterified fractions remained unchanged throughout SD. Basal activity of lecithin cholesterol acyltransferase (LCAT) showed no diurnal biorhythm; on the last 2 days of SD, LCAT activity fell significantly to 71%-80%. In contrast, the decrease in fractional esterification rate (FER) was insignificant. In the vastus lateralis muscle, total cholesterol (TC) was decreased by 40% at the end of SD, the reduction being greater for cholesterol esters (CE) (by 63%) than for free cholesterol (FC) (by 36%). The relative proportion of CE significantly decreased from an initial 14.7% to 9.2% on the last day of SD. During recovery after SD, plasma cholesterol and TG slowly returned to normal. LCAT activity and FER recovered quickly, within 48 h.(ABSTRACT TRUNCATED AT 250 WORDS)

The relationship between anaerobic performance and muscle metabolic capacity and fibre distribution

Relationships between functional anaerobic indicators and the character of cellular muscle energy metabolism were studied. Twelve untrained male students were tested by a specific anaerobic test on the treadmill. The mean values of the anaerobic test were as follows: blood lactate 10.69 mmol . 1(-1), running speed 16.08 km . h-1 and duration 92.67 s. The average distribution of muscle fibres (m. vastus lateralis) was: type I 52.2%, type II A 29.0% and type II B 18.8%. The mean enzyme activity values were: triosephosphate dehydrogenase (TPDH) 4.67 mu kat . g-1 w.w., lactate dehydrogenase (LDH) 5.76 mu kat . g-1 w.w, citrate synthase (CS) 0.21 mu kat . g-1 w.w. and hydroxyacyl-CoA dehydrogenase (HAD) 0.12 mu kat . g-1 w.w. Significant negative correlations were found between delta LA and CS (r = 0.64) and % of fibre type II B and CS (r = 0.78) and positive correlations between % of fibre type I and CS and/or HAD (r = 0.60 and r = 0.62, respectively).

Serum linoleic acid and cardiovascular death in postinfarction middle-aged men

Linoleic acid in serum total lipids was the first variable in the stepwise regression analysis of metabolic, nutritional and cardiovascular factors in a secondary preventive study of postinfarction middle-aged men. It was followed in the regression analysis where the dependent variable was cardiovascular death by previous myocardial infarction, heart volume index and hyperlipoproteinaemia. Linoleic acid was the only fatty acid entering the regression. Unlike other fatty acids, it exhibited by its low percentage an accumulation of deaths. The decreased percentage of linoleic acid was also evident in the comparison of fatty acid patterns of cardiovascular deaths to age- and triglyceride-matched men free from ischaemic heart disease. This study confirms prospective associations found in previously healthy men. Conclusions are drawn about the relevance of low serum linoleic acid to long term prognosis after MI.