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Biomedical subjects

J M Oppert

Publications and source records attributed to J M Oppert.

At least 19 recordsLinked to original sources
PubMed2006

High plasma leptin predicts an increase in subcutaneous adiposity in children and adults.

OBJECTIVE: To investigate the hypothesis that plasma leptin may predict adiposity changes. DESIGN: A population-based cohort study. SETTING: Fleurbaix and Laventie, in the north of France. SUBJECTS: In all, 1175 subjects participated, of whom 946 completed measurements at baseline (1999) and follow-up (2001). After excluding 64 subjects obese at baseline, 882 subjects (478 adults, 404 children 8 years and over) were included in the analysis. INTERVENTIONS: We measured plasma leptin concentrations at baseline and various adiposity parameters at baseline and follow-up. Partial correlation coefficients (r(p)) between baseline plasma leptin and each adiposity indicator at follow-up were calculated with adjustment for baseline age, pubertal stage, adiposity and familial correlations between siblings. RESULTS: Changes in body mass index and percentage body fat were not related to baseline plasma leptin. High baseline plasma leptin predicted an increase (r(p) (P-value)) in the sum of the four skinfolds (0.18 (<0.0001)), the waist circumference (0.16 (0.0003)) and the waist-to-hip ratio (0.29 (<0.0001)) in adults only, and in the hip circumference in adults (0.20 (<0.0001)) and children (0.22 (<0.0001)). After adjustment for a set of four adiposity variables at baseline (percentage body fat, skinfolds, waist and hip circumferences), baseline plasma leptin predicted only changes in the sum of the four skinfolds in adults (0.15 (0.001)), with similar tendency although not significant in children (0.08 (0.13)). CONCLUSIONS: A high leptin relative to baseline fat mass predicts fat mass gain over time, mainly in the subcutaneous location.

Adult↗
PubMed2005

Changes in physical activity explain paradoxical relationship between baseline physical activity and adiposity changes in adolescent girls: the FLVS II study.

OBJECTIVE: To investigate in adolescents relationships between habitual physical activity (PA) and changes in several indicators of adiposity. DESIGN: Longitudinal population-based study. The Fleurbaix-Laventie Ville Sante II (FLVS II) study in Northern France. SUBJECTS: A total of 222 boys and 214 girls aged 8-18 y, not obese at inclusion. MEASUREMENTS: PA (Modifiable Activity Questionnaire) and adiposity (body mass index (kg/m2), percent body fat by bioimpedance analysis, sum of four skinfolds, waist circumference) were assessed in 1999 and 2001. Adiposity indicators adjusted for age and pubertal stage were compared between groups of baseline PA and between groups of PA changes, separately by sex. RESULTS: At baseline, PA was not associated with adiposity indicators in both sexes. In girls only, being in the group with the highest age-relative level of moderate PA at baseline predicted the highest adiposity gain from baseline to follow-up, for all indicators. After adjustment for baseline values, all adiposity indicators were higher at follow-up in girls who had decreased their relative level of moderate PA during follow-up. In boys, changes in adiposity during follow-up were not significantly different across groups of PA changes. However, the sum of skinfolds at follow-up, adjusted for baseline value, tended to be higher in those who decreased their vigorous PA level and lower in those who increased it. CONCLUSION: In adolescent girls, a decrease in PA rather than inactivity per se may result in increased adiposity over time.

Adipose Tissue↗
PubMed2004

[Physical activity as a therapeutic tool in type 2 diabetes: practical aspects].

Physical activity is an integral part of the therapeutic management of type 2 diabetic patients. Its beneficial effects on patients' metabolic control and quality of life are well recognized. The clinical intervention is based on two complementary approaches: to promote physical activity and/or to decrease sedentary behavior, with the aim of long term maintainance. Careful examination of the patient, and assessment of his/her physical capacity and potential risks associated with activity represent the first steps. Assessment of the patient's motivation and stage of change regarding physical activity appears to be a key element for the success of the physical activity project. Main objectives should be clearly defined, as well as the means to reach them (changes in every day-life activities, progressive structured physical exercise), and should be reevaluated and adapted on a regular basis, together with the patient, and whenever possible, with his/her familial/social environment.

Diabetes Mellitus, Type 2↗
PubMed2004

Indicators of abdominal adiposity in middle-aged participants of the SU.VI.MAX study: relationships with educational level, smoking status and physical inactivity.

OBJECTIVES: Abdominal fat accumulation is a risk factor for type 2 diabetes and cardiovascular disease. Identifying the demographic and lifestyle correlates of abdominal adiposity is an important step to target at-risk populations in prevention programs. There are few data of this kind in France. METHODS: Anthropometric indicators of overall (body mass index, BMI) and abdominal (waist hip ratio, WHR; waist circumference, WC) adiposity, educational level, smoking status, and physical activity were assessed in 6,705 middle-aged men and women participating in the SU.VI.MAX study. RESULTS: The likelihood of being obese was increased more than twice in physically inactive subjects of both genders after adjustment for age, smoking status and educational level (OR=2.22, CI95%: 1.74-2.83 in men; OR=2.38, CI95%: 1.84-3.09 in women). Having a high WHR (>=0.95 in men, >=0.80 in women) was more likely in subjects >=50 y, in current smokers, and less likely in men with higher education. The likelihood of having a high WHR was also increased in physically inactive subjects of both genders after adjustment for age, BMI, smoking status and educational level (OR=1.33, CI95%: 1.10-1.60 in men; OR=1.46, CI95%: 1.22-1.74 in women). Having a high WC (>=102 cm in men, >=88 cm in women) was positively associated with age and also with physical inactivity (OR=1.63, CI95%: 1.20-2.22 in women). CONCLUSIONS: These cross-sectional data suggest significant positive associations of physical inactivity with both the WHR and WC, independently of overall adiposity as assessed by the BMI.

Abdomen↗
PubMed2002

[Obesity: epidemiology, pathophysiology and extra-respiratory complications].

Obesity is the most common nutritional disease in industrialized countries and constitutes an important public health issue. Strictly speaking, obesity is an excess of adipose tissue. In practice, body mass index (BMI)=weight (kg)/height (m)(2) is used to determine the degree of excess body weight in a patient. A BMI >=30 kg/m(2), which is associated with significantly higher morbidity and mortality, is generally used as a threshold value for obesity. Despite this measurement, obesity includes a very wide range of variable symptoms. Development of obesity is a multifactorial phenomenon implicating biological, genetic, behavioral, and environmental factors whose interaction and inter-association vary from individual to individual. There are many extra-respiratory complications of obesity which may be somatic (cardiovascular, mechanic, metabolic.), psychological, or social. Abdominal adipose tissue plays an important role in metabolic and vascular complications of obesity independently of the degree of corpulence. As an introduction, we discuss here the definitions concerned as well as the epidemiology, basic pathophysiological mechanisms, and extra-respiratory complications of adult obesity.

Diet↗
PubMed2001

[Physical activity and management of obese patients].

Physical activity is recognized as an integral part of obesity treatment, in association with other therapeutic means. A major benefit of physical activity is the association with better long-term maintenance of weight loss. Physical activity has also positive psychological effects and increases quality of life. An evaluation of the usual level of physical activity and inactivity is needed for each patient. Physical activity counselling should be individualized and graded, in a perspective of individual progression. In subjects with massive obesity, remobilization based on physiotherapy techniques is the first step. All patients should be given simple advice to decrease sedentary behavior: use the stairs instead of the escalators, limit the time spent seated, etc. In general, current physical activity recommendations for the general population fit well with a majority of obese patients, i.e. a minimum of 30 minutes/day of moderate intensity physical activity (brisk walking or equivalent) on most, and preferably all, days of the week. Physical activities of higher intensities (endurance training programme) can be proposed on an individual basis. The type of physical activity required for long-term weight maintenance, and the question of adherence to physical activity recommendations in obese patients should be further investigated.

Exercise↗
PubMed2000

Sweet taste of aspartame and sucrose: effects on diet-induced thermogenesis.

UNLABELLED: Among factors that affect diet-induced thermogenesis (DIT) are the sensory characteristics of food. The aim of this study was to test whether the sweet flavour obtained with a low-energy sweetener (aspartame) or with sucrose have a different effect on DIT. Following a standardized breakfast, 24 healthy male subjects were served three test lunches in a randomized fashion. Lunch contained soft white cheese added with maltodextrins and aspartame, or sucrose, or maltodextrins only (non-sweetened control) (each 900 kcal). Energy expenditure (indirect calorimetry) was monitored during the five postprandial hours. For the first two periods of measurement (30-60 and 90-120 min after meal ingestion), postprandial energy expenditure was significantly increased with sucrose compared to maltodextrins and maltodextrins plus aspartame, whereas no significant difference was found between maltodextrins and maltodextrins plus aspartame. No significant difference between lunches was observed for DIT expressed as incremental area above premeal baseline energy expenditure. Plasma glucose area under the curve was significantly lower for sucrose compared to maltodextrins plus aspartame. Plasma insulin area under the curve was significantly lower for sucrose compared to the other tests foods. IN CONCLUSION: (1) variation in sweet-taste induced by aspartame or by sucrose does not seem to have a major effect on DIT in healthy humans; (2) differences in energy expenditure observed in the early postprandial period suggest a substrate effect.

Adult↗
PubMed2000

High concentration of leptin stimulates myeloid differentiation from human bone marrow CD34+ progenitors: potential involvement in leukocytosis of obese subjects.

OBJECTIVE AND DESIGN: As well as its involvement in control of adipose mass and body energy balance, several reports suggest a link between leptin and hemopoiesis. To test its putative role in human hemopoiesis, we developed a homologous system, ie recombinant human leptin treatment of purified CD34+ progenitors from adult human bone marrow. RESULTS: Leptin (50-100 ng/ml) significantly stimulated the appearance of granulocyte-macrophage colonies in the presence or absence of erythropoietin. The concentration of leptin required for this effect was rather high but within the range of plasma leptin levels observed in obesity. Two results further support the hypothesis that leptin may be involved in the leukocytosis associated with obesity: (i) leptin concentrations in bone marrow and plasma of subjects studied were highly correlated; (ii) leptin and leukocyte count were correlated only in obese subjects. Paracrine effects of locally released leptin from bone marrow adipocytes could also be involved in the regulation of hemopoiesis, a hypothesis supported by marrow immunocytochemistry revealing the close association of CD34+ cells with adipocytes and by previous demonstration that leptin is secreted at a high level by these cells. CONCLUSION: These results indicate that leptin acts on human multilineage CD34+ cells and that high plasma leptin levels associated with obesity could participate in the differentiation of granulocytes from hemopoietic progenitors.

Adult↗
PubMed2000

Self-administered questionnaire compared with interview to assess past-year physical activity.

PURPOSE: The Modifiable Activity Questionnaire (MAQ) is a physical activity questionnaire shown to be both valid and reliable and was initially designed to be interviewer-administered. After translation and adaptation into French, the objective of the study was to compare past-year physical activity data obtained by self-administration of this questionnaire and by interviewer-administration. METHODS: 84 subjects (22 men, 62 women, age 36-63 yr) enrolled in an ongoing prospective study in France (the SUpplementation en VItamines et Minéraux AntioXydants or SU.VI.MAX study) completed both versions of the questionnaire in a randomized order with a mean (SD) delay of 7.9 (5.8) d between the two modes. Past-year leisure and occupational physical activity were expressed as both h x wk(-1) and MET-h x wk(-1) of activity, and television watching was expressed as h x d(-1). Analysis of variance on ranks was used to compare activity variables obtained by self-administration and interview. Agreement was assessed by nonparametric intraclass correlation coefficients. RESULTS: A significant effect of the mode of administration was found only for past-year leisure physical activity with lower values reported in self-administered conditions compared with interview. However, a high level of concordance between the two modes of administration was observed for all variables as shown by the intraclass correlation coefficients: 0.90 for leisure physical activity (h x wk(-1)), 0.82 for occupational activity (h x wk(-1)), 0.83 for total (leisure and occupational combined) physical activity (h x wk(-1)), and 0.97 for television viewing (h x d(-1)). CONCLUSIONS: The agreement between the two modes of administration of the questionnaire suggests that the self-administered version of the MAQ is a valuable tool to assess past-year physical activity and inactivity in self-administered conditions. This instrument could be used in large-scale population studies investigating the relationships between physical activity and health outcomes.

Adult↗
PubMed2000

A polymorphism in the alpha2a-adrenoceptor gene and endurance athlete status.

PURPOSE: In a case control study, we examined the allelic frequencies and genotype distributions of two restricted fragment length polymorphisms (RFLP) in the alpha-2A-adrenoceptor gene (ADRA2A) and beta-2-adrenoceptor gene (ADRB2) among elite endurance athletes (EEA) and sedentary controls (SC). METHODS: The EEA group included 148 Caucasian male subjects recruited on the basis that they had a VO2max > 74 mL O2 x kg(-1) x min(-1). The SC group comprised 149 unrelated sedentary male subjects, all Caucasians, from the Quebec Family Study. After digestion with the restriction enzymes Dra I (ADRA2A) and Ban I (ADRB2), Southern blotting and hybridization techniques were used to detect the mutations in the two ADR genes, which are encoded on chromosomes 10 (q24-26) and 5 (q31-32), respectively. RESULTS: For the Dra I ADRA2A RFLP, we observed a significant difference in genotype distributions between the two groups (P = 0.037). A higher frequency of the 6.7-kb allele was observed in the EEA group compared with the SC group (P = 0.013). No statistically significant difference was found between groups for the Ban I ADRB2 polymorphic site. Genotype frequencies for both genes in both groups were in Hardy-Weinberg equilibrium. CONCLUSIONS: In summary, we found evidence that ADRA2A gene variability detected with Dra I is weakly associated with elite endurance athlete status, and we conclude that genetic variation in the ADRA2A gene or a locus in close proximity may play a role in being able to sustain the endurance training regimen necessary to attain a high level of maximal aerobic power.

Alleles↗
PubMed1998

Plasma leptin and hunger ratings in healthy humans.

Leptin, the ob gene product, is considered as a signal involved in the regulation of energy stores through centrally mediated effects on ingestive behavior and metabolism. To investigate the relationships between appetite-related sensations and circulating leptin in humans, 12 healthy male volunteers were served two test lunches (1200 kcal, 38% carbohydrate, 50% fat, 12% protein) with comparable palatability but resulting in different postprandial hunger ratings, and plasma leptin concentrations were monitored during 8 h after meal ingestion. Whereas postprandial hunger ratings (assessed by visual analog scales) and plasma insulin patterns differed significantly between meals, no significant difference in postprandial plasma leptin concentrations was observed between the two meals. A moderate but significant increase in mean plasma leptin was found over time. We conclude that postprandial plasma leptin concentrations do not significantly differ between two meals inducing different effects on hunger subjective feelings. These data are in agreement with a role for leptin in the regulation of energy balance as a long-term adiposity-related signal rather than a short-term meal-related factor.

Adult↗
PubMed1998

Satiating effect of proteins in healthy subjects: a comparison of egg albumin, casein, gelatin, soy protein, pea protein, and wheat gluten.

The influence of six dietary protein types (egg albumin, casein, gelatin, soy protein, pea protein, and wheat gluten) on satiety and food intake was investigated. Twelve healthy subjects ingested six protein-manipulated lunches (approximately 5.2 MJ, 22% of energy as protein) according to a within-subjects design. Test meals were controlled for energy, macronutrients, fiber, and palatability. Nearly 65% of total protein varied between sessions. After lunch, satiety was assessed for 8 h and energy and macronutrients intakes were measured for 24 h. Blood was collected for determination of postprandial plasma glucose and insulin responses. Results showed no effect of the type of protein on satiety, on 24-h energy or macronutrient intakes, or on postprandial plasma glucose and insulin concentrations. These findings differ in part from those obtained previously in humans, which suggested that proteins may be differentiated in terms of their satiating capacities. We conclude that varying the protein source in a mixed meal does not affect food behavior in healthy humans, probably because coingestion of carbohydrate and fat with protein buffers the kinetics of the physiologic mechanisms implicated in postprandial satiety after a protein load.

Adult↗
PubMed1998

Cardiorespiratory consequences of sleep apnoea syndrome in patients with massive obesity.

Assessment of cardiorespiratory consequences of sleep apnoea syndrome (SAS) is difficult owing to confounding factors, especially obesity, that are strongly associated with SAS. This study was designed to assess the cardiorespiratory consequences of SAS by comparing the results of a comprehensive cardiorespiratory evaluation in apnoeic and nonapnoeic patients with massive obesity. In a retrospective chart-review study, we studied 60 patients with massive obesity defined by a body mass index (BMI) >40 kg.m(-2), presenting no chronic respiratory disease, who underwent an extensive assessment of cardiorespiratory consequences of obesity, including overnight polysomnography, lung function tests, arterial blood gas analysis, evaluation of vascular risk factors, myocardial scintigraphy with dipyridamole stress-test, isotopic ventriculography, Doppler echocardiography and Holter electrocardiogram recording. SAS defined by an apnoea + hypopnoea index (AHI) > or = 10 was diagnosed in 42% of patients (25 out of 60). Mean+/-SD AHI of SAS-positive (SAS+) patients was 38+/-24. Age, BMI, ventilatory function parameters, prevalence of smoking history and diabetes mellitus did not differ significantly in SAS+ versus SAS-negative (SAS-) groups. The following complications were observed more frequently in SAS+ than in SAS- patients: daytime hypoxaemia (35 vs 9%, p<0.02), pulmonary arterial hypertension (36 vs 7%, p<0.05) and increased interventricular septal thickness (50 vs 15%, p<0.03). No association was found between SAS on the one hand and systemic arterial hypertension, coronary artery disease, left ventricular dysfunction and nocturnal cardiac arrhythmias on the other. Nocturnal apnoeas in massive obesity may thus be associated with moderate daytime hypoxaemia, mild pulmonary arterial hypertension and moderate left ventricular hypertrophy, but not with severe cardiorespiratory complications.

Adult↗
PubMed1998

Moderate intake of n-3 fatty acids for 2 months has no detrimental effect on glucose metabolism and could ameliorate the lipid profile in type 2 diabetic men. Results of a controlled study.

OBJECTIVE: To evaluate the effect of a moderate dose of fish oil on glycemic control and in vivo insulin action in type 2 diabetic men with elevated plasma triacylglycerols and to determine the effect of the same treatment on gene expression of GLUT4, lipoprotein lipase (LPL), and hormone-sensitive lipase (HSL) in the abdominal adipose tissue. RESEARCH DESIGN AND METHODS: A total of 12 type 2 diabetic men were randomly allocated to 2 months of 6 g daily of either fish oil or sunflower oil, separated by a 2-month washout interval, in a double-blind crossover design. RESULTS: For glucose metabolism, 2 months of fish oil supplementation compared with sunflower oil led to similar fasting plasma insulin, glucose, and HbA1c. Basal hepatic glucose production did not increase after fish oil. There was no difference in insulin suppression of hepatic glucose production nor in insulin stimulation of whole-body glucose disposal measured by the euglycemic-hyperinsulinemic clamp. Fish oil did not ameliorate the low mRNA level of GLUT4 in adipose tissue of these patients. For lipid profile, fish oil lowered plasma triacylglycerol more than sunflower oil (P < 0.05) and tended to increase the amount of mRNA of both LPL and HSL in adipose tissue. CONCLUSIONS: A moderate dose of fish oil did not lead to deleterious effects on glycemic control or whole-body insulin sensitivity in type 2 diabetic men, with preserved triacylglycerol-lowering capacities.

Basal Metabolism↗
PubMed1997

Plasma leptin and acute serotoninergic stimulation of the corticotropic axis in women who are normal weight or obese.

In some recent studies, glucocorticoid treatment was associated with rapid induction of obese (ob) gene expression in adipose tissue of normal rats and in isolated adipocytes. We studied the effect of acute stimulation of the corticotropic axis on plasma leptin, the ob gene product, in 7 women of normal weight and 12 women with obesity. Under double-blind, placebo-controlled conditions, a single 12.5-mg dose of clomipramine, a serotonin uptake inhibitor, was administered intravenously in 15 minutes. Mean basal plasma leptin was increased more than 3-fold in subjects with obesity compared with subjects of normal weight (35.1 +/- 4.9 ng/mL vs. 8.9 +/- 1.4 ng/mL, p = 0.001). Whereas corticotropin (ACTH) and cortisol responses were increased in women who were obese compared with women who were lean, no significant effect of clomipramine infusion was found on plasma leptin concentrations measured during the following 150 minutes in both groups. There was a strong positive correlation between basal plasma leptin concentrations and body mass index (r = 0.92, p < 0.0001). In six subjects with obesity studied after a moderate weight loss, mean basal plasma leptin was significantly decreased (43.7 +/- 6.4 ng/mL before vs. 28.0 +/- 8.1 ng/mL after, p = 0.04), but the hormonal response pattern to clomipramine administration was unchanged. We conclude that, at least in the short term, an acute stimulation of the corticotropic axis does not seem to increase leptin secretion in humans, as shown by the response to the serotoninergic agent clomipramine.

Adolescent↗