Glycaemic fall after a glucose load. A population-based study.

BACKGROUND AND AIMS: A blood glucose (BG) fall after an oral glucose load has never been described previously at a population level. This study was aimed at looking for a plasma glucose trend after an oral glucose load for possible blood glucose fall if any, and for its impact on coronary mortality at a population level. METHODS AND RESULTS: In subjects from an unselected general population, BG and insulin were detected before and 1 and 2h after a 75-g oral glucose load for insulin sensitivity and ß-cell function determination. Blood pressure, blood examinations and left ventricular mass were measured, and mortality was monitored for 18.8±7.7 years. According to discriminant analysis, the population was stratified into cluster 0 (1-h BG < fasting BG; n=497) and cluster 1 (1-h BG ≥ fasting BG; n=1733). To avoid any interference of age and sex, statistical analysis was limited to two age-gender-matched cohorts of 490 subjects from each cluster (n=940). Subjects in cluster 0 showed significantly higher insulin sensitivity and ß-cell function, lower visceral adiposity and lower blood pressure values. Adjusted coronary mortality was 8 times lower in cluster 0 than 1 (p<0.001). The relative risk of belonging to cluster 1 was 5.40 (95% CI 2.22-13.1). CONCLUSION: It seems that two clusters exist in the general population with respect to their response to an oral glucose load, independent of age and gender. Subjects who respond with a BG decrease could represent a privileged sub-population, where insulin sensitivity and ß-cell function are better, some risk factors are less prevalent, and coronary mortality is lower.

Selenium status, fatty acids, vitamins A and E, and aging: the Nove Study.

To investigate the relationships between aging and selenium status, vitamins A and E, and plasma and erythrocyte fatty acids, we studied 105 healthy subjects (53 women, 52 men) living in Nove, a village near Vicenza (Veneto Region, northern Italy). The subjects were distributed equally for age and sex into four groups: group 1, 20-39 y; group 2, 40-59 y; group 3, 60-75 y; and group 4, > 75 y. A careful selection of subjects to exclude those with chronic or acute diseases was obtained with the collaboration of the three general practitioners operating in Nove. Aging was associated with a progressive decrease in selenium status and in the ratio of plasma and erythrocyte polyunsaturated to saturated fatty acids (P:S). Stepwise multiple linear analysis revealed age, vitamin A, and n-6 polyunsaturated fatty acids (PUFAs) as useful predictors of a substantial proportion of the selenium variability (R = 0.618, R2 = 0.382; P < 0.001) and age and erythrocyte oleic acid as predictors of erythrocyte glutathione peroxidase variability (R = 0.413, R2 = 0.17; P < 0.001).

Membrane fatty acids, glutathione-peroxidase activity, and cation transport systems of erythrocytes and malondialdehyde production by platelets in Laurence Moon Barter Biedl syndrome.

The fatty acid composition of erythrocyte membrane, the glutathione-peroxidase activity of erythrocytes and platelets, the production of malondialdehyde by platelets and the activity of the main systems of transmembrane cation transport have been studied in 5 members of a family, 2 of whom affected by Laurence-Moon-Barter-Biedl Syndrome. A remarkable increase of polyunsaturated fatty acids (particularly arachidonic acid) and of cholesterol/phospholipid molar ratio has been noted. This pattern of membrane lipids was associated to an increment of malondialdehyde production and an increase activity of glutathione-peroxidase. Serum retinol and a-tocopherol were in the normal range, whereas serum selenium was low in 3 out of 5 members. Moreover, the alteration of membrane lipids was associated to a decrease of the maximal velocity of Li-Na countertransport. We speculate that the enrichment of polyunsaturated fatty acids on the cell membranes may represent a condition favoring the lipoperoxidation and therefore the development of the retinitis pigmentosa characteristic feature of Laurence-Moon-Barter-Biedl Syndrome.

Activation of complement by stroma from normal and paroxysmal nocturnal haemoglobinuria red cells.

Stroma from normal, AET-treated and PNH red cells and their KC1-extracts (partially purified on Sephadex G-200) are able to trigger the activation of the alternative complement pathway. This fact has been demonstrated by: 1 - the lysis of PNH cells incubated in serum treated with stroma from normal or PHN-RBC or with their extracts; the addition of Mg2+ or Ca2+ or of their chelators (EDTA, EGTA) to the extract-treated serum enhances or abolishes the lysis 2 - the reduction of complement acitvity in fresh serum incubated for 60' with PNH-extract 3 - the appearance of C3 breakdown products in serum incubated with PNH-extract, demonstrated by crossed immunoelectrophoresis. In contrast, the same stroma (or extract) inhibits the sucrose lysis test, in which the lysis takes place through the classical complement pathway. No differences on the complement activation were observed between PNH and normal RBC stroma and between their chromatographic extracts. These findings may suggest the possible role of diurnal variation of Mg2+ and Ca2+ concentration in precipitating haemolytic attacks and the possibility that small amount of circulating red cell stroma might maintain the haemolysis on PNH RBC.