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Biomedical subjects

B Schulz

Publications and source records attributed to B Schulz.

178 records · Page 10Linked to original sources
PubMedDate not supplied

Relationship between carbohydrate tolerance, insulin secretion, and insulin sensitivity of isolated fat cells from obese protodiabetics.

Six normal weight subjects without any heredity of diabetes (group 1), 3 obese subjects with normal (group 2) and 9 with pathological carbohydrate tolerance (group 3) were characterized by a 2-h glucose infusion test. Adipose tissue fragments were obtained from the abdominal wall by surgical biopsy under intracutaneous anesthesia. Adipocytes were isolated by collagenase digestion and incubated in buffer containing [1-14C] glucose and different concentrations of insulin. The metabolic effect of insulin was expressed as percent increase above control 14CO2 production. Maximal CO2 raised to 207 +/- 25% and 154 +/- 9% in groups 1 and 2, respectively. These values were significantly higher than in obese subjects displaying a pathological carbohydrate tolerance (group 3; 119 +/- 6%). A negative correlation was found between blood glucose levels and biological activity of insulin on adipocytes. The results suggest that insulin sensitivity of target tissue seems to play an important role in development of carbohydrate intolerance.

Adipose Tissue↗
PubMedDate not supplied

Relationship between body fat mass, carbohydrate tolerance and IRI response during glucose infusion in subjects with early diabetes.

We have studied the interrelationship of total body fat mass, carbohydrate tolerance and IRI response in 17 non-obese and obese subjects, who were suspected of having early diabetes. We carried out an i.v. glucose infusion test consisting of a priming injection of 0.33 g/kg followed by constant glucose infusion of 12 mg/kg/min in all persons. Total body fat mass was estimated by the tritium dilution method. There was a positive correlation of body fat mass, fasting glucose concentration and blood glucose concentration at 150 min as well as a strong correlation between body fat mass and BG area 60--120 min as parameters of carbohydrate tolerance in all subjects, i.e. the degree of carbohyrate intolerance was directly related to the quantity of total body fat mass. A similar correlation was found when the non-obese and obese groups were analyzed separately. In neither group did total body fat mass correlate with parameters of IRI response. In obese subjects with pathological carbohydrate tolerance, however, a positive correlation of basal IRI concentration and total body fat mass was found. Furthermore, a close relation between basal IRI level and parameters of carbohydrate tolerance could be demonstrated in obese subjects. The present study failed to demonstrate any correlation of parameters of carbohydrate tolerance and glucose-induced IRI response in either group. Thus, the significant relationship between body fat mass and degree of carbohydrate intolerance indicates that body fat mass plays an important role in the disturbance of blood glucose homeostasis in early diabetes with and without obesity.

Adipose Tissue↗
PubMedDate not supplied

Insulin responsiveness of adipose tissue from normal weight subjects with early diabetes.

In normal weight subjects, classified by a 2-h glucose infusion test as having normal (11), borderline (3) or pathological (9) carbohydrate tolerance (CHT), subcutaneous adipose tissue was removed under intracutaneous anesthesia by surgical biopsy. The biological responsiveness of isolated adipocytes as well as adipose tissue fragments measured as incorportion of (1-14C) glucose into CO2 or triglycerides was studied in the absence or presence of different insulin concentrations. In persons with normal CHT the insulin-stimulated (62.5 microU/ml) glucose conversion to CO2 by adipocytes as well as fat pads increased significantly up to 156 +/- 14% and 285 +/- 30%, respectively. Insulin enhanced the glucose incorporation into triglycerides up to 154 +/- 20% (fat cells) and 258 +/- 30% (fat pads) in adipose tissue from subjects displaying a normal CHT. Rates of glucose oxidation and triglyceride synthesis was markedly reduced in adipose tissue obtained from patients with borderline or pathological CHT. A significant positive relationship was found between glucose oxiation to CO2 and triglyceride production of fat cells and fat pads (r = 0.964 and 0.783, respectively). There was no correlation with responsiveness of adipose tissue to insulin and insulin secretion during glucose infusion test. The results indicate that sensitivity to insulin of target cells might be important for the development of carbohydrate intolerance also in normal weight subjects.

Adipose Tissue↗
PubMedDate not supplied

Frequency and therapy of end-stage renal disease due to diabetic nephropathy in the German Democratic Republic.

The prevalence of diabetic nephropathy among the German Democratic Republic (GDR) population is substantial, as is true of many other countries. An epidemiologic survey performed in the county of Neubrandenburg revealed increased creatinine values in 44.9% of diabetics with diabetes duration greater than 15 years, and in 24.9% of those with the disease less than 15 years. Given these data, the prevalence of renal insufficiency due to diabetic nephropathy is estimated as 27/100,000 in diabetics with greater than 15 years, and 9/100,000 in diabetics with less than 15 years of diabetes, including only patients up to the age of 49 years; this must be substantially greater when considering all age groups. Only 13% of all patients on chronic hemodialysis are diabetics. Although we offer each of our nephropathic diabetics such kidney replacement therapies as dialysis and transplantation, a substantial number of diabetics are not treated, presumably due to advanced macrovascular complications.

Age Factors↗
PubMedDate not supplied

The progression of diabetic nephropathy in type I diabetics: relationship to metabolic control and blood pressure.

This study was designed to investigate the importance of risk factors such as hyperglycemia and elevated systolic and diastolic blood pressures on the progression of renal insufficiency in diabetics suffering from diabetic nephropathy. Seventeen patients with Type I, insulin-dependent diabetes mellitus (IDDM) (8 women and 9 men) undergoing chronic hemodialysis were investigated by retrospective follow-up and compared with 17 age and sex matched IDDM patients without diabetic nephropathy (controls). According to the time interval of creatinine increase from 200 to 600 mumol/l, the patients were divided arbitrarily into two groups with rapidly (group I less than 20 months) or slowly progressive (group II greater than or equal to 20 months) renal insufficiency. This period was 13.4 +/- 2.05 months in group I (age 36.67 +/- 2.47 years, diabetes duration 23.55 +/- 2.37 years) and 32.75 +/- 4.34 months in group II (age 40.62 +/- 2.63 years, diabetes duration 26.62 +/- 2.63 years, P.n.s.), respectively. The IDDM patients studied exhibited individually differing progressions of renal insufficiency at different times after manifestation of diabetes. After 15 years of diabetes duration, both risk factors, that is blood pressure and blood glucose concentrations, were elevated in nephropathic diabetics when compared with controls (p less than 0.01). During the phase of declining kidney function, mean blood pressures were found to be higher in IDDM patients with rapid progression of renal insufficiency when compared with slowly progressing diabetics. Although both risk factors were related to diabetic nephropathy, during the phase of renal insufficiency hypertension appeared to be more closely related to the further deterioration of kidney function.

Antihypertensive Agents↗
PubMedDate not supplied

Simultaneous genotyping of human platelet antigens (HPA) 1 through 6 using new sequence-specific primers for HPA-5.

BACKGROUND: Polymerase chain reaction using sequence-specific primers is widely used for genotyping human platelet antigens (HPA). However, the results of HPA-5 genotyping are still problematic. STUDY DESIGN AND METHODS: New sequence-specific primers were designed for HPA-5 that, together with already published primers, allow simultaneous genotyping of HPA-1, -2, -3, -4, -5, and -6. The reliability of the described protocol was determined by using reference DNA samples as well as samples from healthy blood donors. RESULTS: All primers produced specific amplification products. The genotype and the previously ascertained phenotype of the tested specimens were in concordance in all cases. CONCLUSION: The described polymerase chain reaction protocol allows rapid, reliable, simultaneous genotyping of HPA-1, -2, -3, -4, -5, and -6.

Alleles↗
PubMedDate not supplied

Use of the artificial B-cell (Biostator) in improving insulin therapy in unstable insulin-dependent diabetes.

The present study was designed to improve the conventional subcutaneous insulin treatment of labile insulin-dependent diabetic patients by means of the artificial B-cell (Biostator) during a combination of conventional treatment and a glucose-controlled insulin infusion. Eleven patients with no residual B-cell function and poor metabolic control were studied. All patients were treated as effectively as possible by conventional methods using a combination of regular and intermediate insulin under clinical conditions. In order to determine the inadequacy of previous insulin treatment, all patients were connected to the Biostator, and the profile of daily physical activity was simulated using a bicycle ergometer. Metabolic control was compared during a 6-day period before and after a 30-50-h connection to the artificial B-cell. Using a preselected blood glucose level of 80 mg/dl (4.44 mmol/L), the additional insulin requirement amounted to 45.5 +/- 11.1 U/24 h (N = 6). The day after connection to the artificial B-cell, the patients received a new insulin regimen according to the additional insulin delivery determined by the Biostator. No better metabolic control was achieved and frequent hypoglycemic episodes occurred in this group. Another group (N = 5) was therefore studied at a preselected blood glucose level of 130 mg/dl (7.22 mmol/L). The mean additional insulin delivery by the Biostator was lower (17.2 +/- 2.1 U/24 h; P less than 0.05) and all patients were significantly better equilibrated after the new insulin regimen derived from data given by the Biostator. The ratio of short-acting to intermediate-acting insulin was 3:1; 40% of the total dosage was given in the morning. This study demonstrates that using the Biostator in addition to subcutaneous insulin allows determination of the amount of additional regular insulin that should be administered to improve glycemic control in labile diabetes.

Adult↗
PubMedDate not supplied

Reproducibility of insulin dosage on consecutive days of blood glucose control by an artificial beta-cell in brittle diabetic patients.

The profiles of blood glucose and of insulin dosage were compared between the first and second of 2 consecutive days of Biostator administration under constant conditions in 12 brittle type I diabetic inpatients. All blood glucose criteria and the daily insulin doses were reproducible between these 2 days for the entire group of patients. In nearly all patients, however, there were distinct but unsystematic differences between the 2 days in the diurnal patterns of insulin dose distribution. These differences could be ascribed to some stress reaction or inherent metabolic lability. It is concluded that, in these extremely labile diabetic patients, due to the insufficient short-term reproducibility of the outcome of an extracorporal artificial beta-cell, caution must be used when constant profiles are to be predicted from these doses for open-loop insulin delivery systems or for conventional subcutaneous injection therapy.

Adolescent↗
PubMedDate not supplied

The effect of long-term glibenclamide treatment on glucose tolerance, insulin secretion and serum lipids in subjects with impaired glucose tolerance.

The effects of glibenclamide plus diet (n = 27) or diet alone (n = 18) on glucose tolerance, insulin secretion and serum lipids in non-obese subjects with normal or low insulin responses and impaired glucose tolerance (IGT) has been followed up for two years. Glucose tolerance and insulin secretion were characterized by means of a glucose infusion test consisting of an initial injection of 0.33 g glucose/kg body weight followed by 12 mg/kg body weight/min for 2 h. Dietary treatment did not improve glucose tolerance in normal and low insulin-responders. Glibenclamide plus diet succeeded in improving glucose tolerance only in low insulin responders whereas glucose tolerance remained unchanged in normal insulin responders. There was a significant decrease in fasting and glucose-stimulated insulin levels after two years of glibenclamide treatment in both the normal and low insulin-responders. The body weight was not altered. Triglyceride and cholesterol levels both decreased. In summary, the present study failed to demonstrate an increase in insulin secretion under chronic administration of glibenclamide in subjects with IGT independent of the type of insulin response. From the practical point of view, glibenclamide is of benefit in the treatment of non-obese subjects with IGT and relative insulin deficiency.

Adult↗