[Enzyme immunoassay for the determination of albumin in urine]. / Enzymimmunoassay zur Bestimmung von Albumin im Urin.

Two modifications of a double antibody enzyme immunoassay for the determination of urinary albumin content are described. The method is simple, rapid and precise and can be carried out in test tubes and on microtiter plates as well. In 1:10 diluted urine samples albumin concentrations of 1.25 to 20 mg/l (corresponding to the normal range) can be determined. For a control sample with 0.3 mg/l albumin the intra- and interassay coefficients of variation were 4.9% (n = 11) and 10.4% (n = 21), respectively, on microtiter plates.

Age-dependent relationship of fasting C-peptide concentration and insulin secretion in non-obese subjects with normal glucose tolerance.

The age-dependent relationship of fasting immunomeasurable C-peptide to fasting immunomeasurable insulin (IRI) and IRI response to glucose was studied in 113 non-obese healthy subjects with normal glucose tolerance (oGTT according to the new WHO recommendations), ranging in age from 6 to 44 years. Fasting C-peptide concentration increased significantly in adolescents and adults when compared with children. The higher fasting C-peptide concentration in the adult group might be explained by the concomitant higher fasting blood glucose concentration whereas such relationship was lacking in adolescents. In contrast to this we failed to demonstrate such relationship with regard to fasting IRI levels. There was, however, a relationship between advancing age and early (IRI area 0-30 min), late (IRI area 30-120 min) and total (IRI area 0-120 min) insulin response to glucose. There was a significant correlation between fasting C-peptide concentration and estimates of IRI response in children and adolescents, whereas such relationship was lacking in adults. Based on these results, the present study demonstrates an age-related increase of the pancreatic beta-cell function which might be partly explained by the concomitant higher blood glucose concentration.

Effect of acetylsalicylic acid on insulin sensitivity in subjects with impaired glucose tolerance.

The effect of acetylsalicylic acid (ASA) on tissue sensitivity to insulin was studied in 14 non-obese subjects with impaired glucose tolerance. For the determination of insulin sensitivity a 1 h priming dose-constant insulin infusion technique was used. The percent decrease of plasma glucose and non-esterified fatty acid (NEFA) concentration at comparable steady-state insulin levels was taken as a measure of body sensitivity to insulin. Patients were restudied after daily treatment with 3.0 g ASA over 3 days. The decrease in plasma glucose and NEFA concentration was in the same range prior to and after ASA treatment (20.1 +/- 3.4 vs 20.8 +/- 4.9% and 54.2 +/- 4.8 vs 54.2 +/- 5.4%), indicating no change of insulin sensitivity by ASA treatment. The mean C-peptide concentration during the insulin infusion test did not differ between the two studies. The metabolic clearance rate of insulin was slightly reduced and the disappearance time of insulin was increased after treatment with ASA. In conclusion ASA did not exert any effect on tissue sensitivity to insulin in subjects with impaired glucose tolerance.

[Effect of glibenclamide therapy on carbohydrate and lipid metabolism and insulin secretion in patients with glucose tolerance disorders : a 5-year study]. / Einfluss einer Glibenklamid-Therapie auf Kohlenhydrat- und Fettstoffwechsel sowie Insulinsekretion bei Personen mit gestörter Glukosetorleranz: Verlaufsbeobachtungen bis zu 5 Jahren.

In normal weight persons with impaired glucose tolerance (IGT; normal fasting glycaemia and pathological glucose tolerance) and still normal or already decreased insulin secretion the influence of glibenclamide (maninil) on the carbohydrate and lipid metabolism as well as the insulin secretion was studied after one year (n = 18), after 2 years (n =13), after 3 years (n = 10) and after 5 years (n = 6). Glucose tolerance and insulin secretion were characterized by means of a 2 hours' glucose infusion test (0.33 g/kg as bolus and 12 mg/kg/min over 120 min). In no case the diabetes became manifest during the 5-year duration of the observation. An improvement of the glucose tolerance could be observed up to 3 years, whereas after a 5-year glibenclamide therapy no certain influence on the glucose tolerance and insulin secretion could be proved. In general the improvement of the glucose tolerance was not associated with an increased secretion of insulin, so that an extrapancreatic effect of glibenclamide (improvement of the peripheral insulin sensitivity?) seems to be possible. A complete normalization of the glucose tolerance could be observed only in some individual cases. The body-weight remained constant in all groups, whereas the concentration of triglyceride and cholesterol decreased in their tendency. From clinical and practical point of view the findings would support the opinion that normal weight persons with IGT, particularly in already decreased insulin secretion, have an indication for a glibenclamide therapy.

[Circadian variations in insulin concentrations and blood glucose in non-diabetics as well as insulin requirements in insulin-dependent diabetics]. / Uber tagesrhythmische Veränderungen der Insulinkonzentrationen und der Plasmaglukose bei Nichtdiabetikern sowie des Insulinbedarfs bei insulinpflichtigen Diabetikern.

On the basis of the estimation of the plasma glucose and the insulin concentrations in 10-minute intervals during 24 hours by the mathematical analysis (multiple regression) over relations between the behaviour of plasma glucose and insulin concentration insulin secretion rates independent of plasma glucose can be calculated. In non-diabetics a circadian rhythm of the disposal of insulin - independent of food - is established. Thus the secretion rate increases in the early morning hours still before before the first meal and is maintained in different size up to nearly 18 o'clock. Then it established itself to the level of the nocturnal basal rate. Adequate changes of the insulin need during night are proved in diabetics without endogenic residual insulin secretion by means of the artificial B-cell Biostator. The circadian rhythm of the disposal of insulin take place parallel with adequate changes of other biological parameters and is of importance for the practice of the conventional insulin therapy as well as in the future use of non-measuring value-regulated insulin infusions (open-loop system).

Investigation of insulin sensitivity in early diabetes. I. Procedure for the determination of insulin responsiveness in vivo.

Twenty-three normal weight subjects without any heredity of diabetes were characterized by a 2-hour glucose infusion test. All persons showed a normal carbohydrate tolerance and normal biphasic insulin secretion pattern. For the determination of insulin sensitivity a 1-hour priming dose--constant infusion technique was used. Two 30-minute-periods of insulin infusion (8 and 16 mU/kg, primed by a start injection of 1 and 2 mU/kg, respectively) provoked a decrease of plasma glucose and FFA concentrations by 35 +/- 12.5% and 55 +/- 30.2%, respectively. Values lower than 22.5% (glycemia) or 25% (FFA) indicate a diminished insulin responsiveness. The metabolic clearance rate of insulin did not change at several concentrations of IRI. Thus, the proposed procedure is suitable to study the insulin sensitivity in vivo.

[Determination of 1,2- and 3,4-benzpyrene besides other polycyclic aromatic hydrocarbons in smoked meat products by mass fragmentography (author's transl)]. / Bestimmung von 1,2- und 3,4-Benzpyren neben anderen polycyclischen aromatischen Kohlenwasserstoffen in geräucherten Fleischwaren durch Massenfragmentographie

In comparison with conventional gas chromatographic methods the combined gas chromatography--mass spectrometry with monitoring of two characteristic ions (mass fragmentography) allows a considerable shortening of analysis length and an increase in sensitivity in the determination of the polycyclic aromatic hydrocarbons benzfluoranthene, 1,2- and 3,4-benzpyrene. Analytical experiences in testing of smoked meat products are reported.

Enhancement of glucose-stimulated insulin secretion from isolated rat pancreatic islets by human insulin antibodies.

Isolated pancreatic rat islets incubated in vitro were used as a bioassay system for investigating the influence of human insulin antibodies on insulin secretion. Serum samples with different titres of insulin antibodies were obtained from juvenile diabetics after various periods of insulin therapy. The insulin secretion of isolated islets is enhanced by insulin antibodies and positively correlated to the measured antibody titres in serum.