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Biomedical subjects

V Koivisto

Publications and source records attributed to V Koivisto.

At least 37 records · Page 2Linked to original sources
PubMed1993

Contribution of muscle and liver to glucose-fatty acid cycle in humans.

To examine the influence of elevated free fatty acid (FFA) levels on hepatic glucose production (HGP) and oxidative and nonoxidative pathways of glucose metabolism, 12 healthy subjects participated in two euglycemic insulin-clamp studies performed with and without infusion of Intralipid plus heparin. To elucidate the role of skeletal muscle in this putative interaction, we performed muscle biopsies for the measurement of activities of glycogen synthase (GS), pyruvate dehydrogenase (PDH), and carnitine palmitoyltransferase (CPT). Infusion of Intralipid plus heparin caused an increase in plasma FFA concentrations and rate of lipid oxidation (measured by indirect calorimetry) that was not inhibited by insulin. Suppression of HGP by insulin was impaired by elevated plasma FFA levels. Furthermore, the increase in plasma FFA was associated with a 20% reduction in total glucose metabolism (P < 0.01), which was completely accounted for by a reduction in the rate of glucose oxidation. Although the fractional activity of GS was increased by insulin, elevation of plasma FFA had no influence on this key enzyme of glycogen synthesis. In addition, the activities of PDH and CPT were uninfluenced by the elevation of FFA, suggesting that oxidative processes in skeletal muscle were not a major target for the operative glucose-fatty acid cycle under the current conditions. Taken together, the data indicate that the interaction between FFA and glucose metabolism also involves impaired suppression of HGP by insulin.

Adult↗
PubMed1992

Metabolism of HDL apolipoprotein A-I and A-II in type 1 (insulin-dependent) diabetes mellitus.

Concentrations of HDL cholesterol and apolipoprotein A-I are commonly increased in Type 1 (insulin-dependent) diabetes mellitus but the mechanisms whereby diabetes influences HDL metabolism have not been studied. We investigated the metabolism of HDL apoproteins A-I and II in normolipidaemic Type 1 diabetic men (n = 17, HbA1 6.4-11.9%) without microalbuminuria but with a wide range of HDL cholesterol (0.85-2.10 mmol/l) and in nondiabetic men (n = 18) matched for body mass index and the range of HDL cholesterol. Input rates and fractional catabolic rates for apolipoproteins A-I and II were determined following injection of 125I-apolipoprotein A-I and 131I-apolipoprotein A-II tracers. Additional multicompartmental analysis was performed using a model to describe the kinetics of HDL particles containing only apolipoprotein A-I (Lp A-I) and apolipoprotein A-I and apolipoprotein A-II (Lp A-I/A-II). No gross differences from normal subjects were observed in the mean levels of lipids, lipoproteins, apoproteins and the lipolytic enzymes in the diabetic men as a result of the selection process. Furthermore, the relationship between apolipoprotein A kinetics and plasma HDL cholesterol levels appeared to be preserved in the diabetic group. However, some normal interrelationships were disrupted in the diabetic men. Firstly, the rate of apolipoprotein A-II synthesis was 22% lower than in control subjects (p less than 0.05). Modelling indicated that this was due to decreased input of Lp A-I/A-II particles whereas the input of Lp A-I particles was similar in the two groups. Secondly, there was no correlation between VLDL triglyceride and HDL cholesterol or VLDL triglyceride and the fractional catabolic rate of apolipoproteins A-I and A-II in diabetic men in contrast to that seen in control subjects. We conclude that there is a disruption in the normal association between VLDL and HDL metabolism in Type 1 diabetic men and postulate that the observed differences may be due to the therapeutic use of exogenous insulin.

Adult↗
PubMed1989

Immunoblotting analysis of class-specific antibody response in patients with primary HSV infection.

Class-specific immune response in acute herpes simplex virus (HSV) infections to individual virus specified polypeptide antigens was analysed by immunoblotting. The HSV specified glycoproteins B (gB), C (gC), and D (gD) were detected. IgG-antibody response was shown to develop to various other virus specific polypeptides as well. The IgM- and IgA-antibody responses remained restricted to only a few HSV specific proteins, namely VP 13 (80 kD), VP 20 (52 kD), and VP 23 (40 kD) and to the low molecular weight polypeptides.

Adult↗
PubMed1989

Correlation of HbA1C, glycated serum proteins and albumin, and fructosamine with the 24-h glucose profile of insulin-dependent pregnant diabetics.

To assess the value of various methods for long-term follow-up of diabetic patients, we compared the concentrations of fructosamine in serum with those of various glycated proteins: hemoglobin (HbA1C), total serum proteins (G-prot), and albumin (G-alb), assayed in 30 pregnant insulin-dependent diabetics every two weeks after initial determination of a 24-h blood glucose profile. HbA1C correlated best with the 24-h glucose profile during the succeeding 10-35 days (r = 0.65-0.68, P less than 0.001). G-prot and G-alb correlated nearly as well as HbA1C 10-20 days after the glucose profile (r = 0.54-0.64, P less than 0.01-0.001), but only weakly after 25-35 days. Values for fructosamine did not correlate significantly with the glucose profile 10-35 days after it (r = 0.23-0.36). Evidently the fructosamine assay is not an adequate alternative to HbA1C, G-alb, or G-prot as an index to long-term control of blood glucose in such patients.

Blood Glucose↗
PubMed1988

Phospholipase A2 activity is copurified together with herpes simplex virus-specified Fc receptor proteins.

We purified Fc-binding proteins from herpes simplex virus (HSV)-infected Vero cells by using an inverse immunoaffinity column chromatography. Polyacrylamide gel electrophoresis analysis revealed a single, virus-specific 65-kd polypeptide both in HSV type 1- and HSV type 2-infected cell-derived preparations. A Ca2+-dependent phospholipase A2 activity was demonstrated to be associated with the viral Fc-binding proteins.

Animals↗
PubMed1987

A controlled study of the influence of continuous subcutaneous insulin infusion treatment on diabetic retinopathy during pregnancy.

Forty consecutive pregnant patients with insulin-dependent (Type I) diabetes mellitus were randomized at the end of the first trimester for treatment with conventional insulin therapy (CIT) or continuous subcutaneous insulin infusion therapy (CSII). Nine patients randomized into the CSII group declined the pump treatment. The mean glycosylated haemoglobin (Hb AIc) decreased (p less than 0.001) both in the CIT and the CSII groups with no difference between the groups. Some deterioration in retinopathy was found in 2/18 patients in the CIT group, in 5/13 in the CSII group, and in 3/9 of those who declined the pump treatment. The proportion of patients whose retinopathy progressed did not differ significantly between the groups, and in the majority the deterioration was mild. However, two patients in the CSII group developed acute ischaemic retinopathy, which progressed to proliferative stage in spite of laser treatment. In these two cases the decrease in the Hb AIc level was among the greatest and fastest in the study. These data suggest that a rapid near normalization of glycaemic control by CSII during pregnancy can accelerate the progress of retinopathy in poorly controlled diabetic patients.

Adult↗