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Biomedical subjects

L Heinemann

Publications and source records attributed to L Heinemann.

At least 91 records · Page 5Linked to original sources
PubMed1994

Glucose clamps with the Biostator: a critical reappraisal.

The Biostator makes it possible to perform glucose clamp experiments almost automatically. Thus, blood glucose concentrations can be maintained at (or close to) a target level with substantially less effort than with the manual clamp technique. The automatisation also avoids a potential bias on the part of the investigator. However, as with the non-automated manual clamp technique, blood glucose concentrations do not remain exactly at the target value, as they show a considerable scatter around the target value. This scatter is generated by the time constants of the Biostator, i.e. the whole closed-loop system, and the autoregressive properties of the glucose clamp algorithm used. In order to describe the quality of glucose clamps over time more precisely, "cumulative sums" as an alternative to the usual coefficient of variation can be used. Practical work with the Biostator is burdened with technical difficulties and considerable costs in comparison to the manual clamp technique. Deficits concerning data storage and presentation capability of the Biostator have been overcome by an appropriate programme for an external computer. The use of the Biostator for the glucose clamp technique is not mandatory, but, the use of this machine makes it possible to perform glucose clamp studies under standardised and reproducible conditions.

Algorithms↗
PubMed1994

Trends of acute myocardial infarction morbidity and case fatality in East Germany since 1970.

Because of the high risk factor levels and the high morbidity and mortality of cardiovascular diseases, a Myocardial Infarction Control Programme was implemented in East Germany in the 1970s. To measure its effect, many myocardial infarction registers have operated in the country ever since, and despite some methodological problems the results of these registers now make trend estimations possible. In recent years, we observed no decline in the acute myocardial infarction attack rates in the population aged 25-64 years, and in men there was even a slight increase towards the late 1980s. These somewhat different sex-specific trends run parallel to the trends of the risk factor levels, as well as the cardiovascular mortality rates in men and women. There was no decline in the case fatality rate either during that period. We have to conclude, therefore, that the aims of the Myocardial Infarction Control Programme have not been reached, and both primary and secondary myocardial infarction prevention must be intensified. Cardiovascular morbidity and mortality, under the new conditions existing in East Germany after unification, must be reduced at least to the level observed in West Germany.

Adult↗
PubMed1994

Smoking is associated with progression of diabetic nephropathy.

OBJECTIVE: To investigate the association between cigarette smoking and the progression of diabetic nephropathy. RESEARCH DESIGN AND METHODS: A prospective, follow-up study over one year was conducted in a sequential sample of 34 smokers, 35 nonsmokers, and 24 ex-smokers with type I diabetes, hypertension, and diabetic nephropathy. Progression of renal disease was defined according to the stage of nephropathy as an increase in proteinuria or serum creatinine or a decrease in the glomerular filtration rate. RESULTS: Progression of nephropathy was less common in nonsmokers (11%) than in smokers (53%) and patients who had quit smoking (33%), P < 0.001. In a stepwise logistic regression analysis, cigarette pack years, 24-h sodium excretion, and GHb were independent predictive factors for the progression of diabetic nephropathy. Because blood pressure (BP) was well controlled in these patients and most values were within a normotensive range, neither standing, sitting, nor supine BP values were associated with progression of nephropathy. CONCLUSIONS: Cigarette smoking represents an important factor associated with progression of nephropathy in treated hypertensive type I diabetic patients.

Adult↗
PubMed1994

[Risk factors in hyperlipidemic patients with coronary heart disease one year after PTCA].

The reduction of modifiable risk factors in hyperlipidemic patients with coronary heart disease (CHD) receiving standard medical care in Germany has not been evaluated before. We identified all patients < 65 yrs of age with marked hyperlipidemia (Cholesterol (Chol) > 250 mg/dl, HDL < 20% Chol) among all patients who underwent PTCA during defined periods 1991/92 in the Cardiology department of the Heinrich-Heine-University. The study patients (n = 93, age 54 +/- 8 yrs, 75 men, 18 women) were evaluated 13 +/- 2 months after PTCA for modification of their risk factors, treatments, knowledge, medications and dietary habits with a structured questionnaire and a 5-day dietary protocol. At follow-up Chol and LDL were significantly reduced from 299 +/- 47 to 253 +/- 43, and from 228 +/- 47 to 189 +/- 42 mg/dl, respectively (p < 0.001). 10% of patients had an LDL < 135 mg/dl. In contrast, HDL (43 +/- 9 mg/dl) and triglycerides (242 +/- 138 mg/dl), the percentage of smokers (40%), of overweight patients (38%) and of patients with elevated blood pressure (43%) remained unchanged. During the observation period the number of contacts with physicians was high (12 (1-40)). 32% of patients participated in dietary counselling by a dietician and 42% in an in-patient rehabilitation programme. In 2/3 of patients the knowledge related to hyperlipidemia and a lipid-lowering diet was good. However, according to the dietary protocols the fat intake was high (37 +/- 7% of total calories). Lipid lowering drugs had been prescribed in 68% of patients, predominantly as monotherapy and in low dosage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Incidence and prognosis of stroke episodes in the East German population. Results from a stroke register 1985-1988].

OBJECTIVES: To determine the incidence rate of stroke, case-fatality within 28 days and diagnostic accuracy in stroke cases in the study population. METHODS: Prospective stroke register, including all cases of complete stroke which occurred during 1985-1988 in the population aged 25-64 and 25-74, of 14 districts in East Germany. Case-respectively finding, validation and uniform data collection were carried out by physicians trained to use the WHO-MONICA protocol. RESULTS: Annual age-standardized event rates were 113 per 100,000 for men and 68/100,000 for women aged 25-64, rates for first-ever stroke were 88/100,000 for men and 52/100,000 for women. For both sexes, incidence and event rates rose exponentially with increasing age. Before age 45 more women than men were affected. 34% of patients aged 25-64 had died by 28 days. Case-fatality in men and women aged 65-74 was higher than in those ten years younger (p < 0.01) and tended to be higher in women. 10% of patients aged 25-64 and 26% of those in the age of 65-74 were treated outside hospital. Before age 65, CT examination and angiography were done in only 18 and 20%, respectively; in elderly patients even less frequently. CONCLUSIONS: The findings suggest that since the 1970s there may have been an increase of stroke incidence in the population of Eastern Germany. The high case-fatality following stroke is confirmed. Evidently there are deficiencies in the medical care of elderly stroke patients.

Adult↗
PubMed1993

Action profile of the rapid acting insulin analogue: human insulin B28Asp.

The time-action profile of the human insulin analogue B28Asp, which displays faster absorption rates from subcutaneous tissue compared to soluble human insulin, was studied under euglycaemic glucose clamp conditions (blood glucose 5.0 mmol l-1) in 14 healthy male volunteers. Subcutaneous injection of 0.15 U kg-1 body weight (range 9.5-14.3 U) of the insulin analogue or soluble human insulin resulted in half-maximal glucose infusion rates (after subtraction of mean baseline glucose infusion rates) that were reached significantly earlier after injection of B28Asp (45 +/- 11 (SD) min) as compared to human insulin (58 +/- 25 min, p < 0.05). Forty-five and 60 min after injection of human insulin, glucose infusion rates had increased by 3.4 +/- 1.8 and 4.8 +/- 2.3 mg min-1 kg-1 above baseline glucose infusion rates, reflecting 30 +/- 15 and 42 +/- 17% of maximal action of 10.6 +/- 2.7 mg min-1 kg-1. Following the injection of B28Asp, glucose infusion rates increased by 6.3 +/- 2.7 after 45 min and by 7.9 +/- 2.8 mg min-1 kg-1 after 60 min above baseline glucose infusion rates, reflecting 64 +/- 28% and 81 +/- 26% of maximal action of human soluble insulin (p < 0.001). Peak glucose infusion rates after injection of B28Asp were significantly higher and were reached earlier than after subcutaneous injection of soluble human insulin (p < 0.05 and p < 0.001). The human insulin analogue B28Asp showed a significantly faster onset of action as compared to soluble human insulin.

Adult↗
PubMed1993

Clinical pharmacology of human insulin.

Nowadays, human insulin is used daily by millions of diabetic patients. The biological effect of human insulin is comparable to that of porcine insulin. However, after subcutaneous injection, pharmacological and clinical studies showed pharmacokinetic and pharmacodynamic differences between human and animal insulins. Human insulin tends to have faster absorption and shorter duration of action compared with animal insulin. These differences are more pronounced and can be of clinical relevance with intermediate- and long-acting insulin preparations. Optimal metabolic control can be achieved with either human or highly purified animal insulin preparations, provided appropriate insulin replacement strategies are used.

Animals↗
PubMed1993

Biotrans: description of a data transfer program for the biostator.

Glucose clamp experiments are often performed by means of a Biostator. Due to the fact that this device does not provide data storage, data analysis has to be done manually or data must be fed into the computer. In order to enhance the efficacy of data analysis and to avoid time consuming work, a data acquisition program (Biotrans) has been developed which allows data transfer from the Biostator into an IBM compatible computer. After a complex analysis of incoming data, Biotrans provides on-line data storage and display features (blood glucose concentrations and glucose infusion rate). Off-line analysis of the stored data is accomplished by conventional spread sheet programs, thus permitting complex data calculations and graphic presentation. In more than 300 glucose clamp experiments performed within the last three years Biotrans was an important tool providing data storage capabilities, better control of ongoing events during an experiment and rapid and reliable data analysis immediately after completion of individual experiments.

Glucose Clamp Technique↗
PubMed1992

Hyperinsulinaemia is not linked with blood pressure elevation in patients with insulinoma.

We have investigated the hypothesis that insulin is a causal and independent risk factor for blood pressure elevation in humans by comparing pre- and post-operative blood pressure values of 34 consecutive patients with histologically-confirmed diagnosis of insulinoma and 34 age- and sex-matched control patients. In patients with insulinoma hypoglycaemic symptoms were present for 18 (9-36) months. (Values are given as median and 95% confidence interval or mean and SD). After removal of insulinoma fasting plasma insulin levels decreased from 22 (16-28) mU/l to 11 (6-20) mU/l (p less than 0.003) and minimal fasting plasma glucose concentrations increased from 2.5 (2.0-3.0) to 4.4 (4.2-5.7) mmol/l (p less than 0.002) while blood pressure values remained unchanged. Body mass index before operation was comparable between the groups: 25.5 (5.4) kg/m2 in insulinoma patients and 24.8 (4.7) kg/m2 in control subjects. Pre-operative and post-operative blood pressure values did not differ between the groups, being (systolic/diastolic) 133 (18)/82 (9) mm Hg in insulinoma patients and 128 (15)/78 (10) mm Hg in control subjects before and 129 (19)/80 (10) mm Hg and 125 (11)/76 (7) after surgery. Chronic hyperinsulinaemia in patients with insulinoma is not associated with a detectable elevation of blood pressure values. Correction of hyperinsulinaemia after surgery for insulinoma does not result in blood pressure changes. These results argue against the hypothesis that insulin is an independent causal factor in the development of essential hypertension in humans.

Blood Glucose↗
PubMed1992

Severe hypoglycemia incidence and predisposing factors in 85 pregnancies of type I diabetic women.

OBJECTIVE: To evaluate the incidence and predisposing factors of severe hypoglycemia (SH) in pregnant women with insulin-dependent (type I) diabetes mellitus. RESEARCH DESIGN AND METHODS: SH (impairment of consciousness due to hypoglycemia subsequently treated with glucagon or i.v. glucose) was recorded in all pregnant type I diabetic women (n = 77) who attended our pregnancy clinic during 85 pregnancies from 1986 to 1990. RESULTS: Ninety-four SHs were reported during 35 pregnancies. Of 94 SHs, 84% occurred before the 20th gestational wk (median 12th wk) and 77% during sleep. In the group with SH, there was no permanent maternal sequelae, and there was a favorable fetal outcome (no perinatal death and no congenital malformation). Mean HbA1c values were not different between the group with and without SH for the first half (6.4 +/- 1.1 vs. 6.3 +/- 0.9%) and 2nd half (5.4 +/- 0.6 vs. 5.5 +/- 0.7%) of pregnancy. The percentage of women with SH before pregnancy (51 vs. 28%, P less than 0.05) and the incidence of SH patients before pregnancy (0.49 vs. 0.08 SH/patient/yr) was different between the group with and without SH. CONCLUSIONS: SH is frequent during pregnancies of type I diabetic women with near normoglycemia. The risk for SH is particularly pronounced during the first half of pregnancy and in women with a history of SH.

Adult↗
PubMed1992

Timing between the subcutaneous administration of insulin and consumption of a carbohydrate rich meal.

There is considerable uncertainty as to the appropriate timing of preprandial injections of short acting insulin before consumption of a meal. 8 healthy male volunteers were subjected to a glucose clamp (glucose 4.2 mmol/l) by means of a continuous insulin infusion on two occasions. On each occasion the subjects ingested a standardized meal. Twelve units of short acting insulin were injected subcutaneously either immediately before (A) or 30 min prior to the meal (B). In a control study (C) only the meal was consumed. The maximal increment of insulin concentrations after sc injection was 53.1 (6.9) mU/l in A and 58.6 (5.1) mU/l in B and thus comparable to C (52.8 (4.7) mU/l), however it was reached 30 to 60 min later as compared to endogenous stimulation. Injection 30 min prior to meal resulted in higher insulin concentrations early after the meal, but the glucose infusion rate doubled to 5.3 (0.3) mg/kg/min before the meal in order to prevent hypoglycaemia. Omission of this time interval is less hazardous, but bears the risk of late postprandial hyperinsulinaemia.

Adult↗
PubMed1991

Prevalence of renal artery stenosis in diabetes mellitus--an autopsy study.

The prevalence of renal artery stenosis in diabetic patients is unknown, since no noninvasive and valid screening procedures are available. We have therefore evaluated 5194 consecutive autopsy protocols from patients who died between 1980 and 1988. In addition, all available clinical records for patients with renal artery stenosis (RAS) and a random sample were evaluated. It was found that 73% of patients with RAS were hypertensive, and 53% had diabetes, all but one being Type 2 (non-insulin-dependent). Renal artery stenosis was present in 225 (4.3%) of all patients [95% confidence interval (95% CI), 3.8-4.9], and was not reported in the patients' clinical records in 93% of cases. RAS was present in 8.3% of all diabetic patients (95% CI, 6.8-9.8%), the odds ratio being 3.5 (95% CI, 2.6-4.6). The frequency of renal artery stenosis in diabetic patients with hypertension was 10.1%. Bilateral renal artery stenosis was found in 43% of patients with RAS and diabetes, and in 30% of non-diabetic patients with RAS (P = 0.059). Our results indicate that renal artery stenosis often goes undetected before autopsy. The presence of non-insulin-dependent diabetes mellitus increases the risk of renal artery stenosis. The risk of bilateral renal artery stenosis is greater in diabetic patients. These results may be of significance with regard to the diagnostic evaluation and choice of antihypertensive treatment in hypertensive non-insulin-dependent diabetic patients.

Aged↗
PubMed1991

Hypoglycemic symptoms and frequency of severe hypoglycemia in patients treated with human and animal insulin preparations.

OBJECTIVES: To compare hypoglycemic warning symptoms (main objective) and incidence of severe hypoglycemia (secondary objective) between patients treated with animal and human insulin preparations. RESEARCH DESIGN AND METHODS: Two hundred forty-seven patients on treatment with animal insulin preparations and 276 patients on human insulins, matched for duration of diabetes (16 +/- 11 vs. 15 +/- 10 yr), were recruited for the study. Patients were interviewed with a standardized questionnaire. RESULTS: When asked which symptom usually occurs first during hypoglycemia, 19% of the animal insulin group and 22% of the human insulin group answered "sweating," 19 and 17%, respectively, answered "trembling," and 15 and 11%, respectively, answered "unrest." According to the patients' perception, in both groups, their most reliable hypoglycemic warning symptoms were "trembling" (26 and 22%) and "sweating" (15 and 18%). Six and eight percent of patients, respectively, reported hypoglycemia unawareness and 17 and 18%, respectively, impaired awareness of hypoglycemia. The incidence of severe hypoglycemia was 0.45 cases/patient-yr in patients treated with animal insulins and 0.46 cases/patient-yr in patients treated with human insulin preparations. The differences were not statistically significant. CONCLUSIONS: This study shows that hypoglycemic warning symptoms and the incidence of severe hypoglycemia are comparable between patients on treatment with human and animal insulin preparations.

Adult↗
PubMed1991

The dimensions of health promotion applied to physical activity.

Health promotion is a complementary array of educational and environmental strategies applied in various settings and targeted at selected populations. The few successful and well-described physical activity projects have applied multiple strategies in multiple settings to specific target groups. There is clear and persuasive evidence that regular physical activity improves health. Over the past 20-25 years participation in leisure-time physical activity has increased in Canada, Finland, the USA, and the German Democratic Republic. Unfortunately, more than half the population in each of these four countries remains inactive during leisure time, and total physical activity probably has decreased because of declining activity on the job and for transportation. National physical activity promotion programs need to include both educational and environmental strategies. Regular surveys of physical activity patterns and continued research into the most effective methods to promote regular physical activity are needed.

Exercise↗
PubMed1990

Action profiles of fast onset insulin analogues.

Recombinant DNA technology allows the production of insulin analogues with faster absorption rates from subcutaneous tissue as compared to conventional human regular insulin. We report the time-action profiles of 12 U subcutaneously injected insulin analogues (B9Asp + B27Glu or B10Asp) as evaluated against human regular insulin by means of the euglycaemic clamp technique (blood glucose 5.0 mmol/l) in healthy men. After injection of 12 U of either insulin preparation identical values were found for maximal insulin action (maximal glucose infusion rate, time to peak action), total amount of glucose infused as well as area under the curve of glucose infusion rate. Half-maximal glucose infusion rate was reached significantly earlier after injection of modified insulins (mean +/- SD 38 +/- 7 and 43 +/- 5 min) as compared to regular insulin (56 +/- 14 min, p less than 0.01). Forty-five min after injection of both insulin analogues glucose infusion rate had increased by 7.4 +/- 1.8 or 6.1 +/- 1.8 mg.kg-1.min-1, reflecting 83 +/- 27 or 67 +/- 15% of maximal regular insulin action. In conclusion, the two tested insulin analogues showed similar action profiles, but a significantly faster onset of action as compared to regular insulin.

Adult↗
PubMed1990

Variation in coronary risk factor levels of men and women between the German-speaking MONICA centres.

The aim of this analysis was to compare levels of risk factors for coronary heart disease (CHD) in men and women aged 25-64 years between German-speaking MONICA collaborating centres, the German Democratic Republic (GDR), Augsburg - the Federal Republic of Germany (FRG)(Au), Bremen - FRG (Br), Heidelberg - FRG (He), and Vaud/Fribourg - Switzerland (CH, with a German-speaking minority). Prevalence of cigarette smoking in men showed little variation in four centres (34 to 40%) and was higher in BR men (49%), while it varied from 17% (GDR) to 33% (BR) in women. Mean total serum cholesterol values (mmol/L) were highest in GDR and CH men (both 6.2) and GDR women (6.1), and lowest in both He men (5.7) and He women (5.6). The proportion with cholesterol values greater than or equal to 6.7 mmol/L was largest in CH men (34%) and smallest in FRG (He) women (17%), while lowering the cut-off point from 6.7 to 6.5 mmol/L raised the prevalence of hypercholesterolaemia in all centres by 5 to 10%. Mean values (mmHg) of blood pressure (BP) were highest in both GDR men (140/88) and women (138/86), as was the prevalence of hypertensive BP values. In all centres, women aged 25-34 had BP values approximately 12/5 mmHg lower than age-matched men, but BP values similar to men at age 55-64, which indicates that age-parallel increase in BP was steeper in women than men.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗