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Biomedical subjects

M Haslbeck

Publications and source records attributed to M Haslbeck.

At least 73 records · Page 4Linked to original sources

Reduced insulin binding to hepatic plasma membranes in D-galactosamine-treated rats.

Six to 12 hr after IP injection of 400 mg/kg of D-galactosamine in rats a 5-fold increase in plasma insulin was observed. In addition, impaired glucose assimilation was present after an IV Load in spite of unchanged fasting glucose levels. In streptozotocin-diabetic rats (100 mg/kg IV) plasma insulin remained diminished 12 h after induction of D-galactosamine hepatitis. Under identical conditions of preparation and incubation, the liver plasma membranes of D-galactosamine-treated rats, in both normal and diabetic states, bound only 40--60% as much insulin per mg of membrane protein as those of the control rats. Scatchard analysis suggested that this was due to a decrease in the number of receptor sites in the membranes of the D-galactosamine-injected rats. No difference in the insulin degrading capacity and in insulin-receptor dissociation of the plasma membranes between control and D-galactosamine-treated groups was found. These data suggest that a reduction in the number of hepatic insulin receptors in galactosamine hepatitis can lead to insulin resistance and hyperinsulinaemia.

Animals↗

Extrapancreatic action of sulphonylureas: effect of gliquidone on insulin and glucagon binding to rat liver plasma membranes.

Gliquidone (a second generation sulphonylurea) was administered orally to normal rats 1 h before killing. Gliquidone treatment led to a decrease in plasma glucose, an increase in insulin and a diminution in glucagon concentration. Insulin binding to liver plasma membranes was enhanced by 40% in comparison with controls, whereas glucagon binding was slightly diminished. These findings indicate a greater sensitivity of liver cells to insulin during sulphonylurea treatment and support the view that sulphonylureas potentiate insulin action on the liver.

Animals↗

[The effect of combined therapy with buformin and dichloracetate on blood lactate concentrations in diabetics].

In animals, dichloroacetate (DCA) which activates pyruvate dehydrogenase has been shown to diminish increased blood lactate concentrations due to biguanide treatment. In 10 maturity onset diabetics, therefore, the effect of a combined therapy with buformin and DCA (200 mg b.i.d.) was studied on blood lactate concentrations and compared with an analogous pre- and postinvestigation period of 6 days with buformin treatment alone (100 mg b.i.d.). Mean blood glucose concentrations remained the same during all 3 investigation periods. Also, neither fasting nor postprandially significant differences were found in blood lactate and ketones. In association with a standardized ergometer test, however, the rise in blood lactate was significantly smaller (p less than 0.05) while the patients were on buformin plus DCA, compared to the periods when only buformin was given. Furthermore, less ketone bodies appeared to be utilized by the exercising muscle under the influence of the combined treatment (p less than 0.05). These results are in good agreement with animal studies and suggest that DCA might be as effective in decreasing enhanced blood lactate concentrations in biguanide treated man as in animals.

Acetates↗

[Lactic acidosis in diabetics on biguanides (author's transl)].

A systematic search for cases of lactic acidosis among diabetics on biguanides revealed ten during an eight-month period, while in the preceding ten years not a single case had been definitely diagnosed. This represents a prevelance of 1 in 2000 patients admitted to hospital. All ten were over 60 years old and had previously been treated for heart failure. Most of them had suffered from renal insufficiency for some time. There was no case of biguanide overdosage. Criteria for the diagnosis of lactic acidosis are lactic concentration in blood averaging 18.4 mmol/l and a low pH, averaging 6.9. Serum-biguanide concentration (measured by radioimmuno-assay) was markedly increased. Most of the patients were in circulatory shock on admission or soon after and all of them had a history of gastro-intestinal complaints. Despite intensive treatment with insulin and glucose and careful correction of the acidosis with bicarbonate four of the ten patients died.

Biguanides↗

Investigation of conjunctival vessels in diabetics with and without retinopathy by means of a microcirculation-index.

We were unable to trace an unmistakable correlation between changes on the fundus of the eye and changes on the conjunctiva neither by taking the sum of single findings at the bulbar conjunctiva nor by using a respective index. I.e. the findings of the bulbar conjunctiva are not correlative neither to the stages of diabetic retinopathy nor the duration of diabetes. Clinical experiences make us suppose that the vessels of the fundus of the eye are closely connected to the circulation of the cerebral flow whereas the changes of the conjunctival vascular bed may possibly correlate in a better way with the peripheral vessels. The present results show that the majority of the patients with a high index at the bulbar conjunctiva suffer from peripheral occlusive disease.

Adolescent↗

[Parenteral application of maltose in diabetic patients and controls].

Maltose (10% solution) was infused continuously over 2 h (0,25 g/kg BW/h) in maturity onset diabetics (n=9) and in non-diabetic patients (n=9) serving as controls. During and after infusion changes of parameters measured (blood glucose, IRI, FFA, lactate, pyruvate, uric acid, acid-base status, ketone bodies) were minimal. A significant rise in blood-glucose was observed only in non-diabetics. Serum maltose concentrations increased continuously up to 150 mg/100 ml during infusion and were nearly identical in both groups. Post infusion serum maltose decreased slowing during 7h and urinary maltose excretion was found for 18 h. During the first 3 h controls excreted 4% of infused maltose (1.3% as maltose and 2.7% as glucose). In diabetics excretion of carbohydrates was higher and more variable: 14(1.1-35.9) %. The slight metabolic changes, especially in diabetics and the possibility of supplying more calories are favorable effects of parenteral maltose. However slow elimination and increasing urinary losses depending on dosage and conditions of i.v. maltose application account for the limited utilization of the disaccharide in men. Unless further investigations will have been done maltose cannot be recommended as a sole substitute for carbohydrate in parenteral nutrition.

Blood Glucose↗