Biomedical subjects

A Marttinen

Publications and source records attributed to A Marttinen.

6 recordsLinked to original sources

PubMed1992

Postoperative hyperglycaemia--are the patients diabetic?

The aim of this study was to investigate the occurrence and causes of postoperative hyperglycaemia. Blood sugar was measured after operation in 262 patients who had undergone minor emergency operations, when the patients were receiving 5% glucose infusion at the rate of 170 ml/h. In 32 patients (12%) blood glucose was over 8.0 mmol/l. Serum insulin concentration in these patients was significantly higher than in reference patients, who had blood glucose below 5.5 mmol/l. The number of insulin receptors in red cells and the affinity of insulin to receptors were similar in both groups. Serum cortisol was higher, but free fatty acid concentration lower, in the hyperglycaemic group than in the reference group. The tests done postoperatively were repeated two weeks later without surgical stress. The values recorded, indicating the patients' normal metabolism, did not differ between the two groups, except that serum cortisol was somewhat higher in the reference patients. The oral glucose tolerance test was normal in all patients except one. The results suggest that patients prone to postoperative hyperglycaemia are not diabetic, but that their production of glucose is increased during surgical stress.

Adult↗

PubMed1992

Early dietary antigens delay the development of gut mucosal barrier in preweaning rats.

To determine the effects of early antigen exposure on the maturation of the gastrointestinal mucosal barrier, rat pups were divided into three groups at the age of 14 d. In addition to normal maternal milk, group CM (n = 24) received daily a gavage feed of cow's milk and group PH (n = 20) a whey protein hydrolysate during the experimental feeding period (14-20 d). Controls (n = 15) remained on maternal milk only. At 21 d, when "gut closure" normally occurs, intestinal absorption of horseradish peroxidase (HRP), was examined in vitro in Ussing chambers. The absorption of intact HRP [geometric mean (95% confidence interval)] was significantly higher in group CM [35.3 (16.7, 74.7) ng.h-1.cm-2] than in group PH [5.2 (1.4, 19.5) ng.h-1.cm-2] and in controls [3.4 (0.8, 15.1) ng.h-1.cm-2; F = 5.54, p = 0.006]. The absorption of degraded HRP was comparable in all groups. There were no modifications in electrical parameters in association with increased mucosal permeability to HRP. Furthermore, in group CM electron-microscopic studies disclosed accumulation of HRP in the cytoplasm of the epithelial cells and in the intercellular spaces where cell junctions remained unaltered. These results indicate that early administration of antigens delays the process of gut closure. They further suggest that continuously enhanced endocytosis of macro-molecules is induced by an insult to the mucosa as part of the host response to these antigens, irrespective of the protection afforded by maternal milk.

Animals↗

PubMed1991

Reaction of human non-collagenous polypeptides with coeliac disease autoantibodies.

We identified and purified six human noncollagenous protein molecules that specifically bind to serum IgA from patients with coeliac disease, and which as a combination can act as true antigen to reticulin antibodies. In affinity chromatography, the purified human protein molecules removed antibodies against reticulin and endomysium from serum samples of coeliac disease patients. We postulate that an autoimmune mechanism operates in generating the jejunal damage in gluten-sensitive enteropathy and that the human protein molecules described here act as self-antigens in the disease.

Autoantibodies↗

PubMed1987

Characterization of uraemia-induced decrease in insulin binding on erythrocytes.

In the present study it was found that uraemic plasma contains inhibitors which affect insulin binding on erythrocyte insulin receptors. Insulin radioreceptor assays performed in the absence of uraemic plasma revealed no defects in the receptors of the uraemic erythrocytes. Uraemic plasma caused a 48% decrease in insulin binding on healthy erythrocytes at a high (10.1 ng/ml) insulin concentration, but only a 17% decrease at a low (70 pg/ml) insulin concentration. The inhibition of insulin binding by uraemic plasma decreased during a haemodialysis treatment from 18% to 13% at the low insulin concentration, and from 30% to 23% at the high insulin concentration. Insulin insensitivity in uraemia appears to be due to inhibition of the insulin receptors.

Erythrocytes↗

PubMed1986

Dependence of insulin degradation by intact erythrocytes on receptor binding in diabetic patients.

Degradation of insulin during incubation of erythrocytes at 37 degrees C was studied in relation to insulin binding to membrane receptors. A method was developed for measuring separately the degradation caused by insulinase released from leaky cells into the incubation medium, and the degradation generated by intact cells. In the 23 samples studied, intact erythrocytes generated 16-41%, and cell-free insulinase the rest, 59-84%, of the amount of insulin degradation products formed during 40 min of incubation. The number and affinities of insulin receptors, and the degradation of insulin by intact erythrocytes, were measured in samples from 23 patients with glucose intolerance. Degradation rate correlated well with the receptor number and to a lesser degree with the affinities. The results suggest that insulin binding is a regulatory step for the formation of insulin degradation products.

Cell Membrane Permeability↗

PubMedDate not supplied

Insulin degradation by intact erythrocytes is associated with low-affinity insulin binding sites.

The effect of Con A and glucose on insulin binding and receptor-mediated degradation by intact erythrocytes was studied. Con A blocked totally high-affinity insulin binding but did not change low-affinity binding. Glucose at the concentration of 25 mM produced a bidirectional effect; it increased high-affinity insulin binding but decreased low-affinity binding. Con A did not affect receptor-mediated insulin degradation rate. Glucose caused a clear decrement in insulin degradation rate. These results show that insulin degradation by intact erythrocytes is closely associated with the low-affinity insulin receptor. The two-site model for the insulin receptor is favored by the present findings.

Concanavalin A↗