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Biomedical subjects

M Wauters

Publications and source records attributed to M Wauters.

At least 19 recordsLinked to original sources
PubMed2003

Leptin levels in type 2 diabetes: associations with measures of insulin resistance and insulin secretion.

Interactions between leptin and insulin have been shown previously, in vitro and in vivo. In this study, we evaluate the associations of leptin levels with insulin secretion and insulin sensitivity in type 2 diabetes. Fasting leptin levels, HbA 1c, glucose, insulin, C-peptide, intact and des-31,32-proinsulin were measured in 100 non-insulin-treated type 2 diabetic patients. Glucose, insulin and C-peptide were measured 2 hours after an oral glucose load. Insulin resistance and beta-cell function were calculated using HOMA. Leptin levels were found to be associated with all measures of beta-cell secretion: with fasting and 2 hours insulin and C-peptide, with intact and des-31,32-proinsulin concentrations, and with beta-cell secretion estimated with HOMA. This association was independent of age and body fat in women, but in men, associations with insulin and C-peptide weakened after controlling for fat mass, whereas those with intact and des-31,32-proinsulin disappeared. Fasting insulin and C-peptide levels were also significant in multiple regression analyses, besides gender and fat mass. Insulin resistance, as assessed by HOMA, was strongly correlated with leptin, also after correction for age and fat mass in both genders. We conclude that, besides fat mass and gender - the main determinants for leptin levels in type 2 diabetic subjects as in healthy subjects - insulin secretion and the degree of insulin resistance also seem to contribute significantly to leptin levels.

Adipose Tissue↗
PubMed2001

Polymorphisms in the leptin receptor gene, body composition and fat distribution in overweight and obese women.

OBJECTIVE: Leptin is an adipocyte-secreted hormone involved in body weight regulation, acting through the leptin receptor, localised centrally in the hypothalamus as well as peripherally, amongst others on adipose tissue. The aim of this study was to evaluate whether polymorphisms in the leptin receptor (LEPR) gene were related to obesity and body fat distribution phenotypes, such as waist and hip circumferences and the amount of visceral and subcutaneous fat. METHODS: Three known LEPR polymorphisms, Lys109Arg, Gln223Arg and Lys656Asn, were typed on genomic DNA of 280 overweight and obese women (body mass index (BMI)>25), aged 18-60 y. General linear model (GLM) analyses were performed in 198 pre- and 82 postmenopausal women, adjusting the data for age and menopausal state, plus fat mass for the fat distribution phenotypes. RESULTS: No associations were found between the LEPR polymorphisms and BMI or fat mass. In postmenopausal women, carriers of the Asn656 allele had increased hip circumference (P=0.03), total abdominal fat (P=0.03) and subcutaneous fat (P=0.04) measured by CT scan. Total abdominal fat was also higher in Gln223Gln homozygotes (P=0.04). Also in postmenopausal women, leptin levels were higher in Lys109Lys homozygotes (P=0.02). CONCLUSION: In conclusion, polymorphisms in the leptin receptor gene are associated with levels of abdominal fat in postmenopausal overweight women. Since body fat distribution variables were adjusted for fat mass, these results suggest that DNA sequence variations in the leptin receptor gene play a role in fat topography and may be involved in the predisposition to abdominal obesity.

Adipose Tissue↗
PubMed2001

Visceral fat is a determinant of PAI-1 activity in diabetic and non-diabetic overweight and obese women.

Plasminogen activator inhibitor type 1 (PAI-1), an inhibitor of fibrinolysis and an important and independent cardiovascular risk factor, has been shown to be elevated in obesity and type 2 diabetes. Recent study results have suggested that adipose tissue--visceral fat in particular--could play an important role in the fibrinolytic process.In order to assess the specific role of this fat distribution, we measured PAI-1 activity (AU/ml) and visceral fat (CT-scan at level L4-L5) in 2 groups of 30 overweight and obese diabetic and overweight and obese non-diabetic women. Subjects were matched for age, weight, body mass index, fat mass and total abdominal fat. Visceral adipose tissue and PAI-1 were significantly higher in diabetic women (p = 0.022 and p = 0.004 respectively) than in non-diabetic patients. Visceral fat correlated significantly with PAI-1 activity, even after correction for insulin and triglycerides (r = 0.28, p = 0.034). Stepwise regression analysis showed visceral fat as the most important determinant factor for PAI-1 in the whole group and in the non-diabetic group. In the diabetic group, fasting insulin was the most important determinant. These results show that visceral fat is more important than BMI or total body fat in the determination of PAI-1 levels. Furthermore, the increased amount of visceral fat in type 2 diabetics may contribute to the increase of PAI-1 activity levels and the subsequent increased risk for thrombovascular disease, regardless of BMI and total fatness.

Abdomen↗
PubMed2001

Leptin receptor gene polymorphisms are associated with insulin in obese women with impaired glucose tolerance.

Leptin receptors are present on beta-cells as well as on muscle and fat cells, thus enabling leptin to modulate both insulin secretion and insulin action. Leptin inhibits especially the glucose-stimulated insulin secretion from pancreatic cells. The leptin receptor (LEPR) gene could thus play a role in the regulation of glucose and insulin after an oral glucose load. Therefore, the relationship between LEPR polymorphisms and glucose and insulin response to an oral glucose tolerance test (OGTT) was investigated. Three LEPR polymorphisms (Lys(109)Arg, Gln(223)Arg, and Lys(656)Asn) were typed on genomic DNA of 358 overweight and obese women, aged 18-60 yr. Based on an OGTT, 269 subjects were defined with normal glucose tolerance, and 89 with impaired glucose tolerance (IGT). Associations between genotypes and glucose metabolism were analyzed with a general linear models procedure in pre- and postmenopausal women separately, after adjusting the data for age and fat mass. In postmenopausal women with IGT (n = 24), associations were found with Lys(109)Arg and Lys(656)Asn for fasting insulin (P = 0.05) and with Lys(109)Arg and Gln(223)Arg for the insulin response to an OGTT (P < 0.02). In the same group, trends were found with Lys(656)Asn for fasting glucose as well as in response to the OGTT. In premenopausal women with IGT (n = 65), associations were found with Lys(109)Arg and Lys(656)Asn for overall glucose response to the glucose load. In contrast, no associations with insulin or glucose were found in women with normal glucose tolerance. In conclusion, these data indicate that LEPR polymorphisms are associated with insulin and glucose metabolism in women with impaired glucose homeostasis.

Adolescent↗
PubMed2000

Associations of leptin with body fat distribution and metabolic parameters in non-insulin-dependent diabetic patients: no effect of apolipoprotein E polymorphism.

Leptin levels have been shown previously to be associated with anthropometric parameters such as the body mass index (BMI), total body fat, and subcutaneous fat. Since apolipoprotein E (apoE) polymorphism is known to be a genetic marker affecting the relationship between certain anthropometric and metabolic parameters, we evaluated whether the leptin level and/or associations between the leptin level and body composition in non-insulin-dependent diabetic patients could be determined by apoE polymorphism. In 171 type 2 diabetic patients (105 male and 66 female), body composition (BMI, waist to hip ratio [WHR], fat mass, and visceral fat) was measured and fasting blood samples were obtained to determine the apoE genotype, leptin, glucose, and insulin levels, and the lipid profile. The mean leptin level for the whole group was 11.7 +/- 9.3 ng/mL, with a significant difference (P < .001) between men (7.1 +/- 4.9 ng/mL) and women (19.0 +/- 10.1 ng/mL). No difference was found for leptin levels or anthropometric variables between the 3 different apoE genotypes (E3/E3 homozygotes, E2 carriers, and E4 carriers). Only low-density lipoprotein (LDL) cholesterol was significantly different between the 3 apoE subgroups. The correlations of leptin with anthropometric variables, especially visceral fat, tended to be different between the 3 apoE groups, but this was not independent and no effect was found after controlling for the other parameters in the model. A multiple regression model containing gender, subcutaneous fat, fasting glucose, triglycerides, and high-density lipoprotein (HDL) cholesterol explained 81% of the variance in leptin levels. We conclude that apoE polymorphism has no effect on the leptin level or its associations with other anthropometric and metabolic parameters.

Apolipoproteins E↗
PubMed2000

Human leptin: from an adipocyte hormone to an endocrine mediator.

Leptin is a mainly adipocyte-secreted protein that was discovered 5 years ago. Most of the research following this discovery focused on the role of leptin in body weight regulation, aiming to illuminate the pathophysiology of human obesity. However, more and more data are emerging that leptin is not only important in the regulation of food intake and energy balance, but that it also has a function as a metabolic and neuroendocrine hormone. It is now clear that it is especially involved in glucose metabolism, as well as in normal sexual maturation and reproduction. Besides this, interactions with the hypothalamic-pituitary-adrenal, thyroid and GH axes and even with haematopoiesis and the immune system have also been described. It has been shown that leptin secretion by the adipocyte is partly regulated by other hormones, such as insulin, cortisol, and sex steroids, mainly testosterone. Also, other hormones like thyroid hormone and GH are possibly involved in leptin synthesis. Leptin itself exerts effects on different endocrine axes, mainly on the hypothalamic-pituitary-gonadal axis and on insulin metabolism, but also on the hypothalamic-pituitary-adrenal, thyroid and GH axes. Leptin may thus be considered a new endocrine mediator, besides its obvious role in body weight regulation.

Adipocytes↗
PubMed1998

Are leptin levels dependent on body fat distribution in obese men and women?

Leptin levels are strongly related to total body fat. It is however not yet clear if leptin is also related to visceral fat accumulation or not. In this study, we investigated whether leptin is also associated with body fat distribution and if this association is different in men and women. Leptin was measured in 143 obese subjects (118 women and 25 men) with a body mass index (BMI) greater than 28. Also weight, skinfolds, waist-to-hip ratio (WHR), fat mass by bioimpedance analysis (BIA) were measured, and abdominal visceral and subcutaneous fat were determined by CT scan. Leptin levels were significantly related with BMI, with fat mass (in kg and percentage body fat) as measured by BIA and skinfolds, and with total abdominal fat mass and subcutaneous fat measured by CT scan. No association was found with visceral fat, waist circumference or WHR. In men and women separately, however, a correlation with visceral fat existed. After correction for total body fat, the correlation remained significant only with subcutaneous fat in women. Multiple regression analyses pointed out that percentage body fat was the most important determinant of leptin for all subjects, while for women subcutaneous fat was the most important parameter, and for men alone total abdominal fat. These results suggest that subcutaneous fat seems to be an important factor related to leptin levels.

Adipose Tissue↗
PubMed1991

Left ventricular function changes during pharmacological and physiological interventions and routine activities monitored in healthy volunteers by a portable radionuclide probe (VEST).

A miniaturized radionuclide cardiac probe incorporated in a semi-rigid plastic chest garment has made ambulatory left ventricular (LV) function evaluation possible, with gated nuclear data being stored on tape together with electrocardiographic data, for subsequent off-line processing. After red blood cell labelling with 555 MBq (15 mCi) 99mTc and standard gated blood pool imaging in 45 degrees LAO, we performed a continuous monitoring of LV function in 20 healthy male volunteers (age range: 22-25 years), in resting control conditions as well as during activities (standing, walking, climbing stairs) and after interventions (isosorbide dinitrate intake, Trendelenburg position, inflation of cuffs around the thighs). VEST-monitoring proved to be a reliable method that gave reproducible results: changes of ejection (EF) in basal conditions were lower than 5% in 95% of the patients. Changes in LV function caused by daily activities were easily demonstrated. While standing effected no significant EF changes, walking and climbing increased EF by 6.9% (p less than 0.05) and 21.2% (p less than 0.05) respectively. Changes in LV volumes caused by alterations in venous return were also demonstrated. Compared with baseline, Trendelenburg increased end-diastolic volume (EDV) by 2.9% while isosorbide dinitrate and inflation of cuffs decreased it by 5.7% and 2.2% respectively.

Adult↗
PubMed1991

[Severe hypertriglyceridemia and acute pancreatitis in pregnancy. A case report].

We report the case of a 32-year old woman who developed major hypertriglyceridaemia complicated by acute pancreatitis at 35 weeks of pregnancy. Caesarean section was performed within 24 hours of admission. After delivery, hypocaloric parenteral feeding without lipid emulsion was initiated. The outcome was favourable, and the patient could resume oral feeding after 5 weeks. The incidence of pancreatitis during pregnancy is 1 in 1,000 to 3,000 pregnancies. In the identification of the metabolic abnormality in our patient the differential diagnosis was between type III and type IV hyperlipaemia, according to Fredrickson's classification.

Acute Disease↗
PubMed1989

Predictability of surgery on non-accommodative esotropia.

The aim of the present retrospective study is to determine those clinical parameters which could be helpful on the predictability of postoperative outcome on non-accommodative esotropia. We could conclude that our results are similar to those previously described in the literature, although we could not find any new guidelines, which could predict the postoperative alignment.

Age Factors↗
PubMed1989

[Goal related observation of motor behavior in psychiatry].

The goals to be attained by the patients frequently are determined by the various professions in psychiatry solely before the background of their various specialities. The new observation tool--LOVIPT--is aimed at enabling an integrative approach to be taken, leading from purposive observation of problem behaviour to the formulation of therapy goals. The potential range of objectives is worded in such a way that they can be taken over by other disciplines as well. Development and scientific validation are described in some detail.

Arousal↗
PubMed1981

Luteal function after tubal sterilization.

The luteal function in women after tubal sterilization was evaluated and compared with a control group of women of a similar average age. Progesterone measurements and endometrial biopsies were obtained in the midluteal phase (5 to 10 days before the next menstrual period). The group of women who had been sterilized by tubal ligation or electrocoagulation had a significantly lower (P less than or equal to .001) mean midluteal progesterone level (8.5 +/- 6.0 ng/ml) than the group of women who had been sterilized by Hulka-Clemens clips (15.4 +/0 6.3 ng/ml) and the control group (17.2 +/- 4.8 ng/ml). The comparison between these 3 groups on days 19 and 20 and on days 21 and 22 gave the same statistical results. Progesterone levels were lower than 10 ng/ml in 54% of women after tubal ligation or electrocoagulation, whereas such low values were found in only 20% of women after sterilization by Hulka-Clemens clips and in 12% of the women in the control group. A retarded endometrium was observed more frequently in the women who underwent tubal ligation or electrocoagulation than in those who were sterilized by Hulka-Clemens clips. The most likely hypothesis to explain these differences is that sterilization using Hulda-Clemens clips preserves the continuity of the uteroovarian artery.

Body Temperature↗