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Biomedical subjects

C Hahn

Publications and source records attributed to C Hahn.

At least 91 records · Page 5Linked to original sources
PubMed1985

Cerulein-induced pancreatitis in rats: increased lysosomal enzyme activity and autophagocytosis.

The involvement of lysosomes in the normal secretory process of the exocrine pancreas and in the onset of acute, hormone-induced pancreatitis was studied. The enzymatic activities of cathepsin B and beta-galactosidase were determined in the pancreas of rats that had been stimulated by either maximal (0.25 microgram X kg-1 h-1) or supramaximal (5 micrograms X kg-1 h-1) concentrations of cerulein. Maximal stimulation led to a moderate increase in cathepsin B activity and the ultrastructural appearance of multivesicular bodies. Supramaximal stimulation resulted in formation of large cytoplasmic vacuoles and progressive destruction of acinar cells which was paralleled by a marked increase of lysosomal enzyme activity.

Amylases↗
PubMed1985

Sulfonylureas in insulin-dependent (type I) diabetes: evidence for an extrapancreatic effect in vivo.

The effect of glibenclamide treatment on insulin-mediated glucose disposal was studied in eight C-peptide-negative type I diabetic patients. The patients were studied twice by the euglycemic insulin clamp technique. One of the two experiments was preceded by glibenclamide treatment at the dose of 5 mg, three times daily for 15 days; half of the patients had the first test before and the second test after sulfonylurea treatment, and vice versa. Insulin was infused for four periods of 2 h each sequentially at 0.5, 1.0, 2.0, and 5.0 mU kg-1 min-1; for each insulin infusion period, the steady state plasma free insulin levels were comparable with or without glibenclamide. The mean +/- SEM plasma glucose concentration was 88 +/- 2 mg/dl in both experiments. The insulin-mediated glucose disposal rate was greater with glibenclamide during the first insulin infusion period (which generated plasma free insulin levels within the physiological range) 2.68 +/- 0.32 mg kg-1 min-1 with glibenclamide vs. 1.97 +/- 0.20 mg kg-1 min-1 without glibenclamide (P less than 0.005). However, glucose disposal rates did not differ in the diabetic patients with or without glibenclamide treatment during the second, third, and fourth insulin infusion periods, which generated plasma free insulin levels in the supraphysiological range. These results provide evidence for an extrapancreatic effect of glibenclamide at low insulin concentrations during euglycemic clamping in patients with insulin-dependent diabetes mellitus. However, this effect was not reflected clinically in either an increased rate of hypoglycemic reactions or decreased insulin needs during the short term period of treatment.

Adult↗
PubMed1985

Alterations of insulin and glucose metabolism during cardiopulmonary bypass under normothermia.

Anesthesia, surgical trauma, heparinization, priming volume composition, and temperature control of the heart-lung machine individually affect carbohydrate, protein, or lipid metabolism during cardiac operations. The impact of some of these factors on glucose and insulin regulation was assessed before, during, and after normothermic cardiopulmonary bypass in nondiabetic patients with use of a servo-controlled insulin delivery system. With a glucose-free prime, cardiopulmonary bypass induced a slight hyperglycemia but no endogenous insulin response, suggesting a partial inhibition of insulin secretion. Nonetheless, insulin release could be stimulated by exogenous glucagon. A glucose load in the priming fluid led to marked and persistent hyperglycemia without commensurate insulin release. Elevated stress hormone levels, a concomitant reduction of insulin release and insulin action, and a depression of peripheral glucose utilization, as demonstrated by glucose clamp experiments, contributed to these perturbations of glucose and insulin metabolism. Although the metabolic alterations observed are not critical in routine cardiac operations, they may become clinically significant in postoperative states with unusual persistence of stress conditions.

Blood Glucose↗
PubMed1984

Insulin resistance in Type 1 (insulin-dependent) diabetes: dependence on plasma insulin concentration.

Sensitivity to insulin in vivo was studied in six Type 1 diabetic patients without residual insulin secretion and without clinical insulin resistance, and in eight non-diabetic subjects, using the euglycaemic insulin clamp technique. Insulin was infused for four periods of 2 h sequentially at 0.5, 1.0, 2.0 and 5.0 mU X kg-1 X min-1; for each insulin infusion period the steady-state plasma free insulin levels were comparable in the diabetic and non-diabetic subjects. The mean +/- SEM plasma glucose concentration was 4.9 +/- 0.03 mmol/l in the diabetic subjects (coefficient of variation of plasma glucose values: 5.7 +/- 0.7%) and 4.6 +/- 0.01 mmol/l in the control subjects (coefficient of variation: 5.1 +/- 0.6%). Insulin-mediated glucose disposal was lower in the diabetic than in the non-diabetic subjects at the two lower insulin infusion rates (mean +/- SEM = 2.03 +/- 0.27 versus 4.8 +/- 0.64 mg X kg-1 X min-1 at the first insulin infusion rate, p less than 0.01, and 5.59 +/- 0.59 versus 8.36 +/- 0.61 mg X kg-1 X min-1 at the second insulin infusion rate, p less than 0.01). However, insulin-induced glucose uptake did not differ significantly between the two groups at the third and fourth rates of insulin infusion. These results show that impaired insulin sensitivity in Type 1 diabetes is dependent on insulin concentration.

Adult↗
PubMed1984

[Isolated or combined myocardial revascularization in patients over 65 years of age].

Of a total of 4 952 patients undergoing surgery between 1975 and 1982 for coronary artery disease, 430 (8.7%) were over 65. Single or multiple coronary by-pass was carried out in all patients, either alone or in combination with other procedures (aortic valve replacement: 16 cases; mitral: 10 cases; mitral aortic: 3 cases; mitral-tricuspid: 1 case; vascular surgery: 8 cases; aneurysm resection + mitral stenosis: 15 cases). Hospital mortality was 6.9%. Clinical improvement (NYHA), despite the short follow-up, was most considerable: only 6% of the patients failed to show improvement. The risks of surgery are therefore acceptable and, given the high improvement rate, operation is to be encouraged in this age group.

Aged↗
PubMed1983

[Sensitivity to insulin in type I diabetes. Preliminary report].

In vivo sensitivity to insulin was assessed by the euglycaemic insulin clamp technique in 5 type I diabetic subjects without residual insulin secretion and in 5 non-diabetic control subjects. Insulin was infused at increasing rates of 0.5, 1.0, 2.0 and 5.0 mU/kg/min in 4 periods of 2 hours. The diabetic subjects were resistant to insulin during the 1st and 2nd insulin infusion periods corresponding to the rates of 0.5 and 1.0 mU/kg/min, when compared to the non-diabetic subjects. However, glucose disposal rates were similar in the diabetic and control subjects at the 2 higher insulin infusion rates (2.0 and 5.0 mU/kg/min). Thus insulin resistance in type I diabetes is dependent on insulin concentration.

Adult↗
PubMed1983

[Long-term evolution of children operated on for tetralogy of Fallot].

While open heart surgery has much improved the prognosis of tetralogy of Fallot, surgical repair does not usually restore completely normal anatomy. Residual defects include some degree of pulmonary stenosis, pulmonary regurgitation (unavoidable if the pulmonic valve and valve ring need to be widened by patch), and, sometimes, residual ventricular septal defect. In addition, left and right ventricular dysfunction of mild to moderate degree, unrelated to residual lesions, may be observed. Other late complications may arise from conduction disturbances and ventricular arrhythmias. The occurrence of late sudden death is related to such rhythm disturbances, it occurs particularly in patients with ventricular premature beats on routine ECGs and is probably due to ventricular fibrillation. Patients with such premature beats must therefore be treated with antiarrhythmic drugs. In spite of these late complications, the majority of patients lead a normal life and professional integration is usually excellent. Many patients practise sports. Exercise tests late after surgery show mild or moderate decrease in maximal exercise performance if there are residual lesions of significance, and especially when there is more than one such residua (e.g. pulmonic stenosis and regurgitation). Life expectancy should be normal, at least for postoperative patients with minimal residual lesions.

Age Factors↗
PubMed1983

Instant shift from continuous flow assistance to paracorporeal diaphragm type pulsatile assistance.

Experiments were conducted implementing a special technique for shifting instantaneously from continuous flow to pulsatile flow assistance by using the assistant heart and obtaining the following results: Within only a few minutes, the shift could easily be made from one type of flow assistance to another on calves with normal hearts. In the 10 calves in which ventricular failure was produced, this instantaneous shift from continuous to pulsatile flow assistance brought about remarkable improvements in their hemodynamics. At the occurrence ventricular fibrillation in 6 of the calves, the return to sinus rhythm was possible with aid of this shift mechanism.

Acute Disease↗