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Biomedical subjects

M Hanefeld

Publications and source records attributed to M Hanefeld.

At least 73 records · Page 4Linked to original sources
PubMed1997

The postprandial state and the risk of atherosclerosis.

The results of the Diabetes Intervention Study indicate that postprandial hyperglycaemia, but not fasting hyperglycaemia, is an independent risk factor for myocardial infarction and total mortality in newly detected non-insulin-dependent diabetes mellitus (NIDDM). Blood pressure and triglyceride levels were also found to be risk factors. Data from patients in the Study to Prevent NIDDM show that patients with impaired glucose tolerance (IGT) have higher fasting levels of triglycerides, and higher fasting and postprandial levels of pro-insulin, insulin, and C-peptide levels, compared with those who have normal glucose tolerance (NGT). Postprandial data at 2 h showed that hyperinsulinaemia was prolonged in subjects with IGT compared with their NGT counterparts. Postprandial pro-insulin levels at 2 h were also increased in subjects with IGT, and were found to have the best discriminating power between subjects with IGT and NGT. Those with IGT also secreted markedly higher levels of insulin, indicated by C-peptide levels, than those with NGT. These data support the possibility that subjects with IGT are at an increased risk of conditions such as atherosclerotic disease, even though they have not developed manifest NIDDM. Intervention with agents that can affect risk factors, such as triglyceride levels and postprandial hyperglycaemia, are expected to reduce the risk of atherosclerosis. One promising agent is acarbose, an antihyperglycaemic drug that significantly reduces postprandial insulin and triglyceride levels and has no effect on leptin levels. The ability of acarbose to improve glycaemic control without the potential for inducing hyperinsulinaemia and weight gain appears to give it an advantage over oral antidiabetic agents such as the sulphonylureas.

Adult↗
PubMed1997

Stable isotope ratio analysis of amino acids: the use of N(O,S)-ethoxycarbonyl trifluoroethyl ester derivatives and gas chromatography/mass spectrometry.

N(O,S)-Ethoxycarbonyl trifluoroethyl amino acid esters are formed by the reaction of amino acids with ethylchloroformate plus trifluoroethanol plus pyridine. The use of these derivatives for a rapid and sensitive determination of specific enrichment of stable isotopically labeled tracer amino acids in blood plasma and protein hydrolysates, by using gas chromatography/electron impact mass spectrometry, is discussed.

Amino Acids↗
PubMed1997

Effects of fluvastatin therapy on lipids, antioxidants, oxidation of low density lipoproteins and trace metals.

OBJECTIVE: Oxidation of low density lipoproteins (LDL) is thought to be an important step in the development of atherosclerosis. Trace metals are involved in oxidative processes. It was of interest to determine whether lipid-lowering therapy with fluvastatin, a potent HMGCoA reductase inhibitor, affected LDL oxidation and trace metal levels. METHODS: Twenty hypercholesterolemic patients were treated with fluvastatin (40 mg twice daily) or placebo for 8 weeks in a double-blind, randomized study. LDL composition, antioxidants and oxidizability as well as plasma zinc, copper, selenium and manganese concentrations were investigated. RESULTS: After fluvastatin treatment, total cholesterol was reduced by 24%, triglycerides fell by 26% and plasma Zn fell by 8%. Cu, Se and Mn changed insignificantly. LDL were separated by ultracentrifugation. LDL were reduced by 18%, LDL-C by 29% and LDL-TG by 19%. The concentrations of alpha-tocopherol and retinol in LDL changed insignificantly. LDL preparations were incubated with copper ions (204 mumol.1(-1) LDL-C/3.2 mumol.1(-1) Cu) and formation of conjugated dienes was monitored at 234 nm for 5 h. Treatment with fluvastatin caused a reduction of diene production by 16% and of diene production rate by 14%, effects being significantly different from placebo (P = 0.02). The change of the lagtime did not reach significance; however, it was positively correlated with the change in LDL alpha-tocopherol. In the placebo group, no significant effects were observed. CONCLUSION: Fluvastatin therapy had lipid-lowering and antioxidative effects.

Anticholesteremic Agents↗
PubMed1997

Anomalies of lipoprotein pattern and fibrinolysis in acromegalic patients: relation to growth hormone levels and insulin-like growth factor I.

The influence of hGH and IGF-I levels on lipid-, lipoprotein metabolism and fibrinolysis were studied in 23 patients with active acromegaly (14 women and 9 men, mean age 49.8 +/- 2.1 years) compared to a sex, BMI and age-matched control group. Mean Lp(a) levels were significantly higher in acromegalics than in controls (469.8 +/- 140.1; n = 23 vs. 162.7 +/- 64.9 mg/l; n = 111; p < 0.01). We found elevated apolipoprotein A-I and Apo E-concentrations in acromegalic patients compared to controls (apo A-I: 1.79 +/- 0.06 vs. 1.46 +/- 0.04 g/l; p < 0.01; apo E: 98.35 +/- 6.4 vs. 72.53 +/- 3.38 mg/l; p < 0.05). 30% of the acromegalics showed increased plasminogen activator inhibitor activity (PAI) while 66% had increased tissue-type plasminogen activator (t-PA) concentrations. There was a correlation between hGH and Lp(a) (r = 0.414; p = 0.05), between hGH and PAI (r = -0.59; p < 0.005) and IGF-I and t-PA activity (r = -0.44; p < 0.05). In a subgroup of nine acromegalics Lp(a) was reduced by 32.2 +/- 6.7% (p < 0.05) after a six-month octreotide therapy and HDL2-cholesterol-concentration increased from 0.17 +/- 0.04 to 0.24 +/- 0.04 mmol/l (p < 0.05). In conclusion, our results demonstrate that elevated Lp(a)-concentrations and changes in fibrinolysis contribute to the cardiovascular complications and should therefore be controlled in acromegalic patients.

Acromegaly↗
PubMed1997

Glibenclamide, but not acarbose, increases leptin concentrations parallel to changes in insulin in subjects with NIDDM.

OBJECTIVE: To hypothesize if glibenclamide, which increases insulin levels, also increases leptin concentrations. RESEARCH DESIGN AND METHODS: Leptin is a hormone that regulates weight in mice. In obese humans, leptin concentrations are increased, suggesting resistance to the effects of this hormone. Although short-term infusion of insulin during the hyperinsulinemiceuglycemic clamp does not increase leptin concentration, the effect of oral antidiabetic agents on leptin concentration is unknown. Differing effects can be expected, since glibenclamide acts via stimulation of insulin secretion, whereas acarbose inhibits alpha-glucosidases of the small intestine and has no direct effect on insulin levels. We examined the effect of acarbose (n = 4), glibenclamide (n = 6), and placebo (n = 6) on insulin and leptin levels during 24-h periods before and after 16 weeks of therapy. RESULTS: We observed a significant diurnal variation in leptin concentrations. This was inversely related to insulin levels during the 24-h follow-up with usual diet. Neither the placebo nor acarbose altered leptin concentrations. However, glibenclamide increased leptin concentrations parallel to insulin levels. There were only minor changes in body weight during the l6-week follow-up: decrease in the placebo group (change -0.5 kg/m2, P = 0.07) and acarbose (change -0.7 kg/m2, P = 0.046) and increase in the glibenclamide group (change 0.8 kg/m2, P = 0.27). However, individual subjects who gained weight had increases in their leptin concentrations. The diurnal variation in leptin concentrations was preserved after glibenclamide. CONCLUSIONS: Glibenclamide increases circadian leptin and insulin concentrations, whereas acarbose does not. This observation may help to explain weight gain in subjects treated with glibenclamide and stable weight in those treated with acarbose in the long run.

Acarbose↗
PubMed1997

[Postmenopausal hormone substitution and its effects on the climacteric syndrome, body weight and blood pressure].

The effect of 0.6 mg conjugated equine estrogens in combination with sequential medrogestone (5 mg from day 11 to 21) on climacteric symptoms, blood pressure and weight were investigated in 46 postmenopausal women. The climacteric symptoms were quantified by a modified Kuppermann-Index. After a 3 months' treatment the index decreased from 20.58 to 8.47 (p < 0.001). 28 patients (65%) showed a 50% and more reduction of climacteric symptoms. 40 patients (93%) reported an improvement of their complaints. The body weight remained stable. One patient had to interrupt the treatment due to a cerebral ischemic disease (PRIND). The systolic blood pressure was decreased by 7% and the diastolic by 16% under treatment (p < 0.001). 11 patients with borderline or not treated hypertension returned to normal ranges. 3 of the 4 patients treated with antihypertensiva came off the medicines.

Blood Pressure↗
PubMed1996

Impact of concentrations of glycated hemoglobin, alpha-tocopherol, copper, and manganese on oxidation of low-density lipoproteins in patients with type I diabetes, type II diabetes and control subjects.

The late organ complications in diabetic patients are associated with enhanced oxidation of low-density lipoproteins (LDL). The role of vitamin and trace metal concentrations in this process is not clear. Therefore, we compared the oxidative susceptibility and alpha-tocopherol concentration of LDL with the levels of glycated hemoglobin (HbA1c), copper and manganese. Sixty-three diabetic patients (23 female and 40 male; 53 of type II, 10 of type I) and 35 control subjects (17 female and 18 male) were investigated. The in vitro-formation of conjugated dienes in purified LDL preparations in the presence of copper was followed as absorbance at 234 nm. LDL exhibited a shorter lagtime (44.5 +/- 10.1 vs. 67.8 +/- 16.0 and 50.1 +/- 14.3 vs. 68.8 +/- 14.6 min) for type I and type II diabetic patients vs. sex and age-matched controls, P < 0.001. For all subjects together the lagtime was inversely correlated to HbA1c (r = -0.230, P = 0.023) and positively correlated to LDL alpha-tocopherol/LDL (mol/mol). This ratio was lower in diabetic patients (P < 0.01 for type II) than in control subjects. The copper and manganese plasma levels were not different between diabetic and nondiabetic groups. However, parameters of LDL oxidizability (amount and rate of oxidation) were positively correlated with both copper and manganese concentrations. We conclude that in diabetes the resistance of LDL against oxidation is diminished in relation to the quality of glucose control.

Adult↗
PubMed1996

Risk factors for myocardial infarction and death in newly detected NIDDM: the Diabetes Intervention Study, 11-year follow-up.

The Diabetes Intervention Study (DIS) is a prospective population-based multicentre trial of newly detected cases of non-insulin-dependent diabetes mellitus (NIDDM). This report analyses the risk factors for subsequent coronary heart disease and all-cause death during the 11-year follow-up. The prognostic significance of the categories of the NIDDM Policy Group was validated with respect to the incidence of coronary heart disease and mortality. At baseline 1139 subjects, aged 30-55 years at the time of diabetes detection and classified as diet controlled after a 6-week screening phase, were included. Of the patients 112 (15.2%) suffered from myocardial infarction, 197 (19.82%) of 994 had died. The odds ratio for all-cause mortality compared to the general population for males at the age of 36-45 years was 5.1 and for females 7.0. In multivariate analysis age, blood pressure and smoking were independent risk factors for myocardial infarction and male sex, age, blood pressure, triglycerides, postprandial blood glucose and smoking for death, respectively. The categories of the NIDDM Policy Group target parameters for blood glucose, triglycerides and blood pressure were significant predictors of both CHD and death. Thus, it appears that in NIDDM good control of blood glucose, blood pressure and triglycerides is associated with a lower incidence of coronary heart disease and death rate respectively.

Adult↗
PubMed1996

Determinants for coronary heart disease in non-insulin-dependent diabetes mellitus: lessons from the diabetes intervention study.

In NIDDM a clustering of established coronary risk factors, e.g. the metabolic syndrome is responsible for excessive incidence of myocardial infarction. The harmful effects of these risk factors are aggravated by poor glucose control. Hyperinsulinaemia is associated with a higher level of risk factors for coronary heart disease. Individuals with subsequent myocardial infarction exhibit higher levels of serum insulin at entry. However, insulin in multivariate analysis was no independent risk factor. Perfect control of blood glucose, triglycerides and blood pressure was associated with a lower incidence of coronary heart disease. By extrapolation an integrated approach to correct the anomalies of the metabolic syndrome seems to be necessary to prevent macroangiopathy and improve life expectancy.

Clinical Trials as Topic↗
PubMed1996

[Metabolic syndrome].

Explore the source record for details and available documents.

Diabetes Mellitus, Type 2↗
PubMed1996

Increased clearance of low density lipoprotein precursors in patients with heterozygous familial defective apolipoprotein B-100: a stable isotope approach.

In familial defective apolipoprotein B-100 (FDB) the presence of a mutant apolipoprotein (apo) B-100 (FDB3500Q/W) in LDL markedly reduces their affinity for the LDL receptor, leading to elevated LDL cholesterol levels. However, the hypercholesterolemia in most FDB patients is relatively mild when compared with, e.g., familial hypercholesterolemia (FH). In order to study mechanisms that may partly alleviate the clinical consequences of FDB, we investigated the in vivo kinetics of apoB-100-containing lipoproteins in five FDB heterozygotes (total cholesterol: 7.84 +/- 1.37 mmol/I; total apoB: 1.68 +/- 0.37 g/l; mean +/- SD) and six normolipidemic controls (4.61 +/- 0.62 mmol/l; 0.98 +/- 0.12 g/l) using a stable isotope approach. During and after a 10-12 h primed, constant infusion of either [13C6]phenylalanine or [2H3]leucine, tracer enrichment was determined in apoB-100 from ultracentrifugally isolated VLDL1 (Sf 60-400), VLDL2 (Sf 20-60), IDL (Sf 12-20), LDL1 (Sf 7-12), and LDL2 (Sf 0-7). The rates of apoB-100 production, catabolism, and transfer were estimated by model-based compartmental analysis. The overall fractional catabolic rate (FCR) of IDL apoB-100 in FDB was substantially increased (2.99 +/- 0.68 pools/day vs. 1.70 +/- 0.23 pools/day in controls, P < 0.01). The fractional rate of apoB-100 transfer from IDL to LDL in FDB was decreased (0.97 +/- 0.13 pools/day vs. 1.24 +/- 0.10 pools/day, P < 0.05). The FCR of LDL apoB-100 in FDB was decreased (0.18 +/- 0.07 pools/day vs. 0.56 +/- 0.05 pools/, P < 0.01). Finally, the input rate of LDL apoB-100 in FDB was markedly decreased (9.45 +/- 2.96 mg/kg day1 vs. 15.54 +/- 1.70 mg/kg day1, P < 0.05). Our data suggest that the relatively small increase of LDL concentrations in FDB is due to an increased clearance of LDL precursor particles via the LDL-receptor and apoE-receptors as well as a decreased conversion of IDL to LDL - two mechanisms that distinguish FDB from FH.

Adult↗