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Biomedical subjects

B Schulz

Publications and source records attributed to B Schulz.

At least 127 records · Page 7Linked to original sources
PubMed1983

Muscular exercise in type I-diabetics. I. Different metabolic reactions during heavy muscular work in dependence on actual insulin availability.

The present study focussed on the impact of heavy muscular work upon metabolic homeostasis in insulin dependent (type I) diabetics in situations involving a certain degree of hyper- and hypoinsulinemia. 20 juvenile type I-diabetics were compared with 6 nondiabetic healthy subjects. The diabetics were studied in states of hypo-(trial A) and hyperinsulinemia (trial B) at the start of the exercise. Differences in insulin availability resulted from the different times that had elapsed from the last insulin injection (3 hours in trial A and 1 hour in trial B) before the ergometer test started at 7 a.m. Six diabetics out of 20 patients were studied in both trials A and B to establish the reproducibility of metabolic reactions to the exercise. Bicycle ergometer tests were carried out in the upright position at 5 graded steps of 50 W, 75 W, 100 W, 125 W and a load near to exhaustion. Rest periods of five minutes were allowed between these work periods for taking blood samples before and after each work load. Plasma glucose, FFA, glycerol, lactate, alanine, IRI and HCP concentrations were investigated. The blood pressure at rest and during exercise was measured, and the physical working capacity (PWC170) was calculated according to Wahlund on the basis of the heart rate response to exercise. The results of the exercise tests reflect clearly the different metabolic reactions to heavy muscular work despite the relatively slight differences in insulin availability at the start: --Exhausting muscular work during the hypoinsulinemic state resulted in hyperglycemia and exaggerated lipolysis. --Heavy muscular work in a hyperinsulinemic state resulted in a reduced blood glucose level and antilipolytic reactions in comparison to nondiabetics. These findings suggest the great necessity of an adequate insulin availability during heavy muscular work in juvenile type I-diabetics.

Aerobiosis↗
PubMed1983

A stimulatory effect of tolbutamide on the insulin-mediated glucose uptake in subjects with impaired glucose tolerance (IGT).

Several studies have indicated that the long-term effectiveness of sulfonylurea therapy in the treatment of type-II diabetics is due to a potentiation of insulin action. The present investigation was undertaken in order to elucidate whether or not there is also an acute effect of sulfonylureas on insulin-mediated glucose uptake. Nine non-obese subjects classified as having impaired glucose tolerance formed the study group. In vivo insulin sensitivity was assessed by using the glucose controlled insulin infusion system (Biostator) without or with a contemporary 3-hour tolbutamide infusion. Studies were performed on subsequent days, and each subject served as its own control. Glucose was given at a fixed rate of 0.011 mmol/kg b.w./min. The computer program was set to maintain plasma glucose concentration at 3.89 mmol/l. The amount of exogenous insulin necessary to keep glycemia at this steady-state level has been accepted as an estimate of insulin sensitivity. Mean plasma glucose and insulin concentrations were constant and comparable in control and sulfonylurea treated groups. Under our experimental conditions tolbutamide did not provoke any increase of C-peptide secretion. There was no significant alteration of insulin counterregulatory hormones (glucagon and growth hormone) either. On the other hand, for the disposal of identical quantities of glucose the necessary amount of insulin has been found to be reduced by one third due to tolbutamide treatment indicating a higher insulin sensitivity. The mechanism by which tolbutamide intensifies the insulin effect is unknown. It seems to be that a successful short-term sulfonylurea therapy on glucose utilization is associated with some alterations on the receptor and/or post-receptor level.

Blood Glucose↗
PubMed1983

Ergometric heart rate, blood pressure and work capacity (PWC170) in type I diabetics with diabetes-specific microangiopathy.

118 male and 68 female type I diabetics and 25 male and 23 female nondiabetic healthy controls were compared during submaximal bicycle ergometer tests using four work stages (duration: 6 min each) of 50 W, 75 W, 100 W and a submaximal stage producing a heart rate of 170 min-1. We found that male type I diabetics with and without retinopathy who had significantly higher than normal heart rates both at the start and during the ergometer test also had above normal ergometric blood pressures. Female type I diabetics, in contrast, did not differ significantly from the controls in terms of heart rate before and during the ergometer tests. The PWC170 of all male type I diabetics was, in contrast to that of the female patients, lower than that of the controls. In diabetics with diabetic nephropathy there was no correlation between exercised acceleration of the heart rate and the degree of nephropathy despite their higher heart rates at the beginning and during the ergometer test, but a correlation was found between the ergometrically increased blood pressure and the severity of the diabetic nephropathy. In male type I diabetics cardiocirculatory adaptation to muscular work was reduced, and this reduction became more marked as the degree of diabetic microangiopathy increased. Compared with the controls, the increase in systolic blood pressure evoked by activity on the ergometer in male and female type I diabetics was disproportionate to the actual load and correlated with the degree of diabetic microangiopathy.

Adult↗
PubMed1983

Further support for heterogeneity of insulin response and insulin sensitivity in non-obese subjects with glucose intolerance.

The relationship of insulin secretion and insulin sensitivity was studied in 67 age- and body weight-matched non-obese subjects, classified as having a normal glucose tolerance or glucose intolerance (50 g oral glucose load). Insulin response was studied by means of a 2 h glucose infusion. For the determination of insulin sensitivity a 1 h priming dose-constant insulin infusion technique was used. The per cent decrease of plasma glucose level at comparable steady-state insulin levels served as a measure of body sensitivity to exogenous insulin. In patients with glucose intolerance the early (delta IRI area 0-5 min) and late (delta IRI area 30-120 min) insulin responses to iv glucose were significantly reduced in comparison to controls. Controls and subjects with glucose intolerance showed considerable heterogeneity of insulin responses. Patients with glucose intolerance and relative insulin deficiency were not less responsive to insulin than subjects with normal glucose tolerance. There was, however, a wide variation of insulin sensitivity within the two groups. There was a weak significant inverse correlation between insulin response to glucose and insulin sensitivity for the two groups combined and for controls and subjects with glucose intolerance separately. The results demonstrate that the majority of non-obese patients with glucose intolerance and relative insulin deficiency does not exhibit a reduced responsiveness to insulin and therefore hypoinsulinaemia but not insulin resistance is the primary defect for an abnormal glucose tolerance in these group of subjects.

Adult↗
PubMed1983

[Methodologic aspects and results of a complex long term analysis of a perinatal/peripartal care system. 3. Dynamic aspects].

One important premise for estimation of the development of the results of defined care systems is the observation of movements in time. Besides the knowledge of internal systemic changes also the influence of external factors has to be considered, especially volume and structure of the clientel. Simple methodic statements are sufficient analysing the development complexly.--The secular dynamic of the care system has been objected by uniform use of a defined trend-ratio. The influences after the second world war and some actual trends are reported besides the longtime trend explicitly. Finally a workinghypothesis is formulated in regard to the reasons of preterm labour and fetal retardation.

Adult↗
PubMed1983

[Methodologic aspects and results of a complex long term analysis of a perinatal/peripartal care system. 4. Systemic aspects].

Important signs of our present development are high dynamics, increasing complexity and active-preventive orientation. Additional progresses of methods are inevitable for further progress in practice and knowledge. Functional purposeful methods in organisation are necessary. The central problem is the step by step crossing from structural institutional to functional-regional care systems and way of thinking. Methodological-heuristic resources are the concept of a functional system and the theory of hierarchic control systems in a limited scale.

Adult↗
PubMed1982

[Effect of a combined diet-training program on the insulin sensitivity of obese persons with normal or disordered glucose tolerance].

The majority of the obese persons is characterized by a disturbed glucose tolerance and an increased insulin secretion. The cause of this apparent contradiction lies in the existence of an insulin resistance. In 23 obese persons (relative weight greater than 120% according to Möhr and Johnson) with normal or disturbed glucose tolerance the effect of a diet restriction lasting 4 weeks (700 kcal/die) or of a combined diet training programme on the body weight, serum lipids, state of conditioning (PWC170) and insulin sensitivity in vivo was investigated. The insulin sensitivity was characterized by means of 1 h insulin infusion test. At comparable peripheral steady state insulin levels the relative decrease of the plasma glucose and free fatty acid concentration is a measure of the insulin sensitivity in vivo. In 9 obese persons with disturbed glucose tolerance observations of the course over 1 year are existing. The finding demonstrate that only a combined diet training programme leads to a significant improvement of the insulin sensitivity and prevails a unique dietary treatment. The measure of the improved insulin effectivity directly correlates with the effect of conditioning. The reduction of the body weight obtained is about double as large in a combined diet conditioning treatment as after a unique restriction of the diet (18% or 10% of the relative weight). Triglyceride and cholesterol levels significantly decrease, the HDL-cholesterol increases in tendency. On the other hand, the results are unsatisfactory after one year. The therapy regime is a promising strategy for the reduction of the insulin resistance in adiposity as a preventive medical measure, provided a good cooperation and motivation on the side of the patient is present.

Blood Glucose↗
PubMed1982

Discrepant effect of the prostaglandin synthesis inhibitor acetylsalicylic acid on insulin and C-peptide response to glucose in man.

The prostaglandin synthesis inhibitor acetylsalicylic acid (ASA) increases acute insulin response to glucose and improves glucose tolerance in man. In an effort to provide further information on the mechanism whereby ASA improves glucose tolerance, we studied the effect of ASA on C-peptide, insulin, pancreatic glucagon (IRG), growth hormone (HGH), nonesterified fatty acids (NEFA) and glycerol responses to glucose in 11 non-obese subjects with impaired glucose tolerance. The glucose tolerance was evaluated by means of a 2 h-glucose infusion test. A daily treatment with 3.0 g ASA over 3 days caused a significant increase of acute (delta IRI area 0-5 min) and late (delta IRI area 30-120 min) insulin response and an improvement of glucose tolerance. By contrast, C-peptide response was in the same range prior to and after ASA treatment. Thus, the C-peptide/insulin ratio was decreased by about 50% due to ASA treatment. IRG, HGH, NEFA and glycerol responses to glucose were not altered by ASA treatment. In summary, the discrepant effect of ASA on C-peptide and insulin responses suggest that changes of insulin metabolism may be involved in the mechanism of ASA induced increase in peripheral insulin levels. The improvement of glucose tolerance after ASA application seems to be related to the biologic effect of higher circulating insulin levels but not to alteration of insulin antagonists, such as IRG, HGH and NEFA.

Adult↗
PubMed1982

Effect of sulfonylurea treatment on in vivo insulin secretion and action in patients with non-insulin-dependent diabetes mellitus.

The effect of glipizide treatment on diabetic control and on in vivo insulin secretion and action was studied in 20 patients with non-insulin-dependent diabetes mellitus (NIDDM). Patients were examined before and after a minimum of 3 mo treatment. Mean (+/- SEM) fasting plasma glucose level fell from 264 +/- 12 mg/dl to 172 +/- 10 mg/dl (P < 0.001) after glipizide treatment, and this was associated with a fall in total plasma glucose response to a test meal of approximately 35%. Mean (+/- SEM) fasting plasma insulin levels increased slightly from 15 +/- 2 micronU/ml following sulfonylurea treatment, and the total plasma insulin response to the test meal increased by 63%. However, there was no correlation (r = - 0.20) between the increase in plasma insulin response and the fall in plasma glucose levels that occurred as the result of sulfonylurea therapy. Glipizide treatment also led to enhanced in vivo insulin action, whether measured by the insulin clamp technique (P < 0.001) or the insulin suppression test (P< 0.02). Furthermore, in this instance there was a significant correlation (r - 0.69, P < 0.001) between the enhanced insulin action and the improvement on diabetes control. Thus, chronic therapy with glipizide, a new sulfonylurea agent, led to increased in vivo insulin secretion and insulin action. These results lend direct support to the assumption that sulfonylurea compounds have a substantial extrapancreatic effect on glucose homeostasis, and suggest that this effect contributes to the therapeutic efficacy of these drugs.

Aged↗
PubMed1982

Evaluation of insulin resistance in non-obese subjects with impaired glucose tolerance.

Insulin resistance was estimated in nine subjects with impaired glucose tolerance (IGT) and eleven healthy, age and body-weight matched controls. Glucose tolerance and insulin response were evaluated by means of a 2h-glucose infusion test. Insulin resistance was determined by measuring the steady state plasma glucose response (SSPG) to a continuous infusion of glucose (6 mg . kg-1 . min-1 or 12 mg . kg-1 . min-1), insulin, epinephrine and propranolol for 150 minutes as described previously by other authors. The endogenous insulin secretion (C-peptide) was inhibited by epinephrine and propranolol in controls and subjects with IGT irrespective of a low (6 mg . kg-1 . min-1) or high (12 mg . kg-1 . min-1) glucose infusion. Steady-state plasma levels of exogenous insulin were virtually identical in all groups studied. There were no significant differences in the pancreatic glucagon, growth hormone, FFA and glycerol response during the SSPG period between controls and subjects with IGT. In comparison to controls the mean SSPG was significantly higher in subjects with IGT (during low and high glucose infusion) suggesting the existence of insulin resistance in these subjects. A higher glucose dose as described earlier by other investigators does not provide a better discrimination of controls and subjects with IGT concerning their degree of insulin resistance. Finally, there was a direct correlation between the SSPG and glucose tolerance in the total group. In conclusion, our results have confirmed the validity of an infusion technique of glucose, insulin, epinephrine and propranolol for evaluation of insulin sensitivity in vivo. In addition, our findings have added further support for insulin resistance in subjects with IGT which is directly proportional to the degree of glucose intolerance.

Blood Glucose↗
PubMed1982

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.

Adult↗
PubMed1982

[Transplantation of the kidneys from newborn donors, using the Mini-Lewe minipig as a model].

The importance of kidneys from newborn donors in transplantation has not been clearly defined. The purpose of this study was to investigate the degree of morphological and functional adaptation of the newborn kidney in an adult recipient. 7 MLS-matched kidneys from Lewe minipig puppies (age: 3-4 weeks) had been transplanted en bloc to their mothers with immediately bilateral nephrectomy. Preliminary results suggested that arterial vasculature and blood supply are the limiting factors in adaptation of newborn donor kidneys in adult recipients.

Animals↗
PubMed1982

[Methodological aspects and results of complex long-term analysis of a perinatal/peripartum monitoring system. 1. Practical starting point].

Active area-covering action to prevent possible complications by early selection of potentially endangered women from among the entire female population of the area concerned, which should, desirably, be under fullest possible medical observation, this has come to be a major characteristic of modern obstetric medicine in the "most developed countries". Appropriate methods have to be devised for high-continuity optimisation of all organisational facilities herefore required. In this paper, methodical approaches are submitted for discussion, as a result of a comprehensive long-term analysis of patients in a big hospital. "Criteria of optimum" are covered in this first communication. Regional weight class rates, weight-class-standardised mortality and early morbidity (5' Apgar score) are proposed as criteria of universal applicability.

Birth Weight↗
PubMed1982

[Methodological aspects and results of complex long-term analysis of a perinatal/peripartum monitoring system. 2. Structural aspects].

In medical attention to patients, achievement and risk are in close correlation. Coherent definition of the term of "risk", therefore, is a primary demand which must be met for systematic optimisation of systems for perinatal care. The definition introduced in this paper will enable critical appraisal of undifferentiated risk control, calculation of an upper limit value of theoretical effectiveness, and assessment of effectiveness in terms of health policy. It is also an uninvolved approach to reduction of characteristics. The suggestions made are backed up by a large bulk of results.

Female↗
PubMed1981

[Effect of glibenclamide therapy on carbohydrate and lipid metabolism and insulin secretion in patients with glucose tolerance disorders : a 5-year study].

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.

Blood Glucose↗
PubMed1981

Evaluation of insulin resistance during inhibition of endogenous insulin and glucagon secretion by somatostatin in non-obese subjects with impaired glucose tolerance.

Insulin resistance was studied in seven non-obese male subjects with impaired glucose tolerance and four healthy, age and body-weight matched male control subjects by means of a continuous intravenous infusion of somatostatin, glucose and insulin over 150 min. Glucose tolerance was evaluated by means of a 2-h glucose infusion test. Endogenous insulin (C-peptide), growth hormone, and glucagon secretion were suppressed by somatostatin in both groups. Steady-state plasma insulin and glucose levels were achieved between 90-135 min. Since similar steady-state levels of exogenous insulin were achieved, the resulting steady-state plasma glucose level provided a direct estimate of the ability of insulin to dispose of the infused glucose. The glucose levels were higher in subjects with impaired glucose tolerance with values of 14.6 +/- 1.8 mmol/l compared with 5.1 +/- 1.2 mmol/l in control subjects (p less than 0.01), thus indicating insulin resistance. There was a direct correlation between the steady-state plasma glucose level and glucose tolerance suggesting that the degree of glucose intolerance is proportional to the degree of insulin resistance. These results revealed that decreased insulin sensitivity is found in non-obese subjects with impaired glucose tolerance.

Adult↗