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Biomedical subjects

C Bouchard

Publications and source records attributed to C Bouchard.

At least 379 records · Page 21Linked to original sources
PubMed1994

The response to exercise with constant energy intake in identical twins.

Seven pairs of young adult male identical twins completed a negative energy balance protocol during which they exercised on cycle ergometers twice a day, 9 out of 10 days, over a period of 93 days while being kept on a constant daily energy and nutrient intake. The total energy deficit caused by exercise above the estimated energy cost of body weight maintenance reached 244 +/- 9.8 MJ (Mean +/- SEM). Baseline energy intake was estimated over a period of 17 days preceding the negative energy balance protocol. Mean body weight loss was 5.0 kg (SEM = 0.6) (p < 0.001) and it was entirely accounted for by the loss of fat mass (p < 0.001). Fat-free mass was unchanged. Body energy losses reached 191 MJ (SEM = 24) (p < 0.001) which represented about 78% of the estimated energy deficit. Subcutaneous fat loss was slightly more pronounced on the trunk than on the limbs as estimated from skinfolds, circumferences, and computed tomograply (CT). The reduction in CT-assessed abdominal visceral fat was quite striking, from 81 cm2 (SEM = 5) to 52 cm2 (SEM = 6) (p < 0.001). At the same submaximal power output level, subjects oxidized more lipids than carbohydrates after the program as indicated by the changes in the respiratory exchange ratio (p < or = 0.05). Intrapair resemblance was observed for the changes in body weight (p < 0.05), fat mass (P < 0.01), percent fat (p < 0.01), body energy content (p < 0.01), sum of 10 skinfolds (p < 0.01), abdominal visceral fat (p < 0.01), fasting plasma triglycerides (p < 0.05) and cholesterol (p < 0.05), maximal oxygen uptake (p < 0.05), and respiratory exchange ratio during submaximal work (p < 0.01). We conclude that even though there were large individual differences in response to the negative energy balance and exercise protocol, subjects with the same genotype were more alike in responses than subjects with different genotypes particularly for body fat, body energy, and abdominal visceral fat changes. High lipid oxidizers and low lipid oxidizers during submaximal exercise were also seen despite the fact that all subjects had experienced the same exercise and nutritional conditions for about three months.

Adipose Tissue↗
PubMed1994

Relation between BglII polymorphism in 3beta-hydroxysteroid dehydrogenase gene and adipose tissue distribution in humans.

The aim of this study was to investigate the association between a restriction fragment length polymorphism (RFLP) at the 3beta-hydroxysteroid dehydrogenase locus and adipose tissue distribution phenotypes. A total of 132 unrelated individuals from the Quebec Family Study were followed prospectively for an average period of 11.3 years. The BglII polymorphism in exon 4 of the 3beta-HSD gene was detected by PCR. Body mass, body fat, and regional fat distribution indicators were adjusted for age and age2 within each gender. Associations were assessed in unrelated adults with ANOVA across three genotypes. No association was found for the indicators of body mass, body fat, and regional distribution of adipose tissue measured in 1992. In women, the changes (difference between data collected in 1992 and at entry) in the sum of six skinfolds (p=0.04), abdominal skinfold (p=0.01), and abdominal skinfold adjusted (p=0.03) for the sum of six skinfolds at entry were related to the BglII polymorphism at the 3beta-HSD locus. These relations were not found in men, but they gained less body mass and body fat over the 11.3-year period. This suggests that sequence variation at the 3beta-HSD locus or in neighboring genes on chromosome 1 may contribute to individual differences in body fat content and adipose tissue distribution in adult women, particularly in abdominal adipose tissue deposition as they grow older and gain body fat.

3-Hydroxysteroid Dehydrogenases↗
PubMed1994

Natural and recombinant soluble low-affinity Fc gamma R: detection, purification, and functional activities.

Studies on the identification, cloning, and biochemical characterization of natural and recombinant human and mouse low-affinity soluble Fc gamma R (sFc gamma R) have been developed using various methods. RT-PCR and/or biochemical analyses have demonstrated that low-affinity sFc gamma R (i) are generated by enzymatic cleavage of membrane-associated receptors or by an alternative splicing of the transmembrane region encoding exon and (ii) comprise only the extracellular domains or these domains plus the intracellular region of the membrane-associated molecules, respectively. Functional studies indicated that recombinant sFc gamma R bind mouse and human IgG subclasses with a binding profile identical to that of their membrane counterparts and inhibit Fc gamma R-mediated functions such as immune complex binding or ADCC. In addition, it has been demonstrated that a mouse recombinant truncated sFc gamma RII inhibits antibody responses to T-dependent antigens as well as B-cell proliferation and that a human recombinant truncated sFc gamma RIIIB blocks the Ig production by activated human peripheral blood mononuclear cells. Finally, different immunoassays devised to detect and quantitate circulating sFc gamma R showed that sFc gamma R serum levels vary in circumstances such as injections of protein antigens, in parasitic infections, in tumor-bearing mice, in patients with multiple myeloma (MM), or upon infusions of IgG or Fc gamma fragments in MM or immune thrombocytopenic purpura patients. The use of recombinant sFc gamma R, as well as the availability of monoclonal and polyclonal antibodies directed against different regions of these molecules, makes it possible to characterize further the biological effects of sFc gamma R and their biochemical and immunochemical characteristics, as well as to define their putative ligands on cell membranes.

Amino Acid Sequence↗
PubMed1994

Are gender differences in cardiovascular disease risk factors explained by the level of visceral adipose tissue?

It has been suggested that the lower prevalence of cardiovascular disease in women before menopause in comparison with men may be explained by differences in body fat distribution, plasma lipoprotein levels and indices of plasma glucose-insulin homeostasis. Thus, gender differences in visceral adipose tissue accumulation measured by computed tomography and metabolic variables were studied in 80 men and 69 pre-menopausal women, aged 23-50 years. Despite the fact that women had higher levels of total body fat (p < 0.0001), they displayed lower areas of abdominal visceral adipose tissue (p < 0.06) and a lower ratio of abdominal visceral to mid-thigh adipose tissue areas than men (p < 0.0001). After adjustment for body fat mass, women generally displayed a more favourable risk profile than men which included higher plasma HDL2-cholesterol and lower plasma insulin, apolipoprotein B and triglyceride levels (p < 0.01). Metabolic variables adjusted for body fat mass were then compared between genders after control for differences in abdominal visceral adipose tissue area. After such controls, variables related to plasma glucose-insulin homeostasis were no longer significantly different between men and women. Gender differences for plasma concentrations of triglyceride, apolipoprotein B and the ratio of HDL2-cholesterol/HDL3-cholesterol also disappeared, whereas plasma concentrations of HDL-cholesterol, HDL2-cholesterol as well as the ratio of HDL-cholesterol/total cholesterol remained significantly higher in women than in men (p < 0.01). These results suggest that abdominal visceral adipose tissue is an important correlate of gender differences in cardiovascular disease risk. However, additional factors are likely to be involved in gender differences in plasma HDL-cholesterol levels.

Adipose Tissue↗
PubMed1994

Systolic blood pressure during submaximal exercise: an important correlate of cardiovascular disease risk factors in normotensive obese women.

Body fatness, plasma lipids, lipoproteins, indicators of glucose metabolism, and resting as well as submaximal treadmill exercise systolic blood pressures (BPs) were measured in a sample of 25 normotensive obese premenopausal women. No association was observed between body fatness, risk factors for cardiovascular disease, and resting BP. However, body fatness and plasma cholesterol, low-density lipoprotein cholesterol (LDL-CHOL), LDL apolipoprotein B (apo B), and apo B concentrations, as well as the high-density lipoprotein cholesterol to cholesterol (HDL-CHOL/CHOL) ratio, showed significant correlations with systolic BP measured during submaximal exercise. In addition, fasting plasma insulin concentrations and the glucose and insulin areas under the oral glucose tolerance test (OGTT) curve were both significantly associated with systolic BP during submaximal exercise. Partial correlation analyses revealed that the associations between submaximal exercise systolic BP and plasma apo B and LDL apo B levels were in part independent from the level of obesity. These results indicate that plasma concentrations of lipoproteins and insulin are important correlates of the systolic BP during submaximal exercise in obese premenopausal women. Further analyses performed on two subgroups indicated that women with high exercise systolic BP values exhibited significant differences in their metabolic profile in comparison to women with low BP during exercise. These results suggest that the absolute systolic BP recorded during submaximal exercise may be useful in the early detection of individuals at risk for the development of cardiovascular disease in resting normotensive obese women.

Adult↗
PubMed1994

Impact of exercise intensity on body fatness and skeletal muscle metabolism.

The impact of two different modes of training on body fatness and skeletal muscle metabolism was investigated in young adults who were subjected to either a 20-week endurance-training (ET) program (eight men and nine women) or a 15-week high-intensity intermittent-training (HIIT) program (five men and five women). The mean estimated total energy cost of the ET program was 120.4 MJ, whereas the corresponding value for the HIIT program was 57.9 MJ. Despite its lower energy cost, the HIIT program induced a more pronounced reduction in subcutaneous adiposity compared with the ET program. When corrected for the energy cost of training, the decrease in the sum of six subcutaneous skinfolds induced by the HIIT program was ninefold greater than by the ET program. Muscle biopsies obtained in the vastus lateralis before and after training showed that both training programs increased similarly the level of the citric acid cycle enzymatic marker. On the other hand, the activity of muscle glycolytic enzymes was increased by the HIIT program, whereas a decrease was observed following the ET program. The enhancing effect of training on muscle 3-hydroxyacyl coenzyme A dehydrogenase (HADH) enzyme activity, a marker of the activity of beta-oxidation, was significantly greater after the HIIT program. In conclusion, these results reinforce the notion that for a given level of energy expenditure, vigorous exercise favors negative energy and lipid balance to a greater extent than exercise of low to moderate intensity. Moreover, the metabolic adaptations taking place in the skeletal muscle in response to the HIIT program appear to favor the process of lipid oxidation.

Adipose Tissue↗
PubMed1994

[Incidence and characteristics in identification of abused children: cross-cultural comparison].

This study compared the incidence and characteristics of reported child abuse cases in two different ethnic groups. Incidence was calculated based on the total number of cases (N = 2,854) reported to child protection authorities between July 17, 1988 and March 31, 1989. In a sample of 953 reports, the following were examined: the source of the reporting, type of abuse, substantiation and age of the child. The incidence was found to be slightly higher among Haitian group compared to French-Canadian group. In the former case, reporting tended to originate with public authorities such as the police or school personnel. Cases tended to consist mainly of physical abuse, with very few cases of sexual abuse. Most involved adolescents. These results suggest that child-rearing practices of Haitian families are in conflict with the values of the host community, and that there exist similar value-based conflicts between Haitian parents and their children.

Adolescent↗
PubMed1994

Mechanism of inhibition of lipopolysaccharide-stimulated mouse B-cell responses by transforming growth factor-beta 1.

Transforming growth factor-beta 1 (TGF beta 1) is a pleiotropic cytokine which inhibits growth of many cell types and positively or negatively regulates the production of Ig isotypes. By using mouse resting B cells stimulated by lipopolysaccharide (LPS), we investigated whether the effect of TGF beta 1 on Ig production is related to its effect on cell growth. We show that low doses of TGF beta 1 stimulate IgG3 and IgG2b production whereas higher doses inhibit IgM, IgG3, IgG1 and IgG2b secretion and cell proliferation. TGF beta 1 titration curves and kinetics experiments suggested that the inhibitory effect on Ig secretion and B-cell growth are closely related. We defined the phase at which TGF beta 1 exerts its anti-proliferative effect on mouse B cells. TGF beta 1 does not modify the increase in expression of class II antigens which occurs before transition from G0 to G1. However, it partially inhibits the induction of expression of low-affinity Fc gamma RII and cell enlargement which both begin during the early G1 phase, and it totally blocks induction of the expression of transferrin receptors, a marker of the late G1 phase. Thus, TGF beta 1 blocks LPS-stimulated mouse B cells in the early G1 phase, and this results in inhibition of Ig production.

Animals↗
PubMed1994

Prognostic significance of early cardiac index measurements in severely burned patients.

Invasive monitoring during early resuscitation was performed. To compare the heamodynamic results of severely burned patients, the results of 38 patients hospitalized between 1988 and 1991 in the burn centre of Lyon were retrospectively reviewed. Survivors and non-Survivors' data were compared. No difference existed between the two groups in age, unit burn score, fluid requirement and dose of dobutamine. Survivors had a significantly higher cardiac index, O2 delivery and systolic blood pressure index than non-survivors. It is suggested that the ability to sustain a high cardiac index in response to the burn injury plays a role in the outcome of the patients. There is an indication that dobutamine could have a beneficial effect in this way. Further studies are needed to confirm the benefit of the maintenance of high cardiac index levels by the pressors.

Adult↗
PubMed1994

Modulation of 5-HT release in the guinea-pig brain following long-term administration of antidepressant drugs.

1. The aims of the present study were to determine whether long-term 5-hydroxytryptamine (5-HT) reuptake blockade and inhibition of type-A monoamine oxidase (MAO-A) lead to an enhancement of the electrically evoked release of tritum from guinea-pig brain slices preloaded with [3H]-5-HT, and to assess the sensitivity of the terminal 5-HT1D autoreceptor, the alpha 2-adrenoceptor also located on 5-HT terminals, and the 5-HT3 receptor that modulates 5-HT release following these two types of antidepressant treatments. 2. The electrically evoked release of tritium was significantly enhanced following a 21-day treatment with the 5-HT reuptake blocker, paroxetine and the reversible MAO-A inhibitor, befloxatone, in preloaded slices of the hypothalamus, hippocampus and frontal cortex 48 h after removal of the osmotic minipumps used to deliver the drugs. 3. The inhibitory effect of the terminal 5-HT autoreceptor agonist, 5-methoxytryptamine, on the evoked release of tritium was attenuated in slices of the hypothalamus, hippocampus, but not frontal cortex, following the paroxetine treatment. In the befloxatone group, the effectiveness of 5-methoxytryptamine was unaltered in the same brain structures. 4. The sensitivity of the alpha 2-adrenoceptor on 5-HT terminals, assessed using UK 14.304, was attenuated in hypothalamus, hippocampus, but not frontal cortex slices prepared from befloxatone-treated guinea-pigs and preloaded with [3H]-5-HT. The paroxetine treatment did not alter the sensitivity of this alpha 2-adrenoceptor in the hypothalamus. 5. The sensitivity of the alpha 2-adrenoceptor on noradrenaline terminals, also assessed using UK 14.304, was not altered in hippocampus and hypothalamus slices preloaded with [3H]-noradrenaline following the long-term befloxatone treatment. 6. In frontal cortex slices, [3H]-5-HT uptake was no longer significantly attenuated after a 21-day treatment with paroxetine, whereas it was still markedly inhibited in hypothalamus slices. The enhancing effect of paroxetine on the evoked release of [3H]-5-HT in the superfusion medium was no longer evident in frontal cortex slices of the paroxetine group. These data indicate that long-term 5-HT reuptake blockade desensitized the 5-HT transporter in the frontal cortex. 7. The capacity of the 5-HT3 receptor agonist, 2 methyl-5-HT, to enhance the electrically evoked release of tritium was not altered in hypothalamus, hippocampus, and frontal cortex slices prepared from befloxatone-treated guinea-pigs, but was significantly attenuated in the paroxetine group also treated for 21 days. Following a 2-day paroxetine treatment, the enhancing effect of 2-methyl-5-HT on tritium release was unaltered in frontal cortex slices.

Animals↗
PubMed1994

Population evaluations of health related fitness from perceptions of physical activity and fitness.

The possibility of predicting health related fitness using questions on occupational and leisure activity was explored in 172 men and 178 women. ANOVA and multiple regression equations related questionnaire responses to objective fitness measures including body mass index, circumferences, skinfolds, body fat, blood glucose, uric acid, total cholesterol, HDL-cholesterol and triglycerides, PWC150, blood pressures, and resting heart rate. Reported occupational activities bore little relationship to health related fitness. Self-perceptions of moderately frequent and moderately intense leisure activity, plus at least average perceived fitness relative to age-matched peers, were associated with a favorable body fat content and lipid profile, whereas indicators of cardiovascular health (a low resting heart rate and a high PWC150) were linked with perceptions of frequent and intense activity, plus a perceived fitness level higher than that of a peer reference group. Based on these findings, a simple scoring of reported activity for use in fitness counseling is suggested.

Adult↗
PubMed1994

Principal components of fitness: relationship to physical activity and lifestyle.

Interrelationships between metabolic and cardiorespiratory health were examined in 350 healthy adults. Four principal components accounted for 66.7% of the variance in 172 males (M) and for 62.4% in 178 females (F). Factor 1, "obesity," related to body mass index, abdominal circumference, total skinfold thickness, and (M only) abdominal/hip circumference ratio. Factor 2, "cardiovascular fitness," had loadings from resting heart rate and PWC150/kg. Factors 3 and 4 were related to total cholesterol and HDL-cholesterol, respectively (plus blood pressures, particularly in F). Factor 1 was linked to caffeine consumption and to exercise frequency (F) or perceived intensity (M). Factor 2 was linked to perceptions of activity relative to others (M and F) and to the intensity of activity (M only). Factors 3 and 4 were associated with perceived fitness and physical activity relative to others. Because perceptions of physical activity and fitness lack consistency, it is suggested that health be judged more directly from simple measures of health related fitness that require little subject cooperation.

Adult↗
PubMed1994

ApoB-100 gene EcoRI polymorphism. Relations to plasma lipoprotein changes associated with abdominal visceral obesity.

The aim of this study was to investigate whether the EcoRI restriction fragment length polymorphism (RFLP) of the apolipoprotein (apo) B-100 gene influences the associations described among obesity, regional adipose tissue distribution, and plasma lipoprotein levels. For this purpose, blood samples were collected from 56 healthy men for whom we had extensive measurements of regional adipose tissue distribution (both anthropometric and computed tomography-derived measurements) and data on the plasma lipoprotein-lipid profile. DNA was extracted from white blood cells, and RFLP analysis was performed. Subjects were classified into two groups on the basis of their apoB-100 EcoRI genotype: subjects homozygous for the major 11-kb allele, the 11/11 group (n = 40), and subjects carrying the minor 13-kb allele, the 13/11 group (n = 16). Subjects carrying the 13-kb allele had lower percent body fat and abdominal adipose tissue accumulation than subjects homozygous for the 11-kb allele (P < .05). Although leaner, the 13/11 group did not show a more favorable plasma lipoprotein-lipid profile than the group homozygous for the 11-kb allele. In fact, after statistical control for the difference in percent body fat between the two genotype groups, the 13/11 group showed significantly higher plasma cholesterol levels (P < .05) and nearly significantly higher apoB levels than the 11/11 group (P = .06). The association patterns between indices of regional adiposity and plasma cholesterol and apoB levels were also different between the two EcoRI genotype groups. Only in the 13/11 group was the abdominal visceral adipose tissue area significantly associated with these plasma variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

DNA variation in the genes of the Na,K-adenosine triphosphatase and its relation with resting metabolic rate, respiratory quotient, and body fat.

The aim of this study was to investigate in 261 subjects from 58 families the association between DNA variation at the genes coding for the Na,K-ATPase peptides and resting metabolic rate (RMR), respiratory quotient (RQ), and percent body fat (%FAT). Five restriction fragment length polymorphisms (RFLP) at three Na,K-ATPase genes were determined: one at the alpha 1 locus (BglII), and two at the beta locus (beta MspI and beta PvuII). Haplotypes were determined from the two variable sites of the alpha 2 gene (alpha 2 haplotypes) and the beta gene (beta haplotypes). There was a strong trend for %FAT to be related to the RFLP generated by BglII at the alpha 2 exons 21-22 in males (P = 0.06) and females (P = 0.05). RQ was (a) associated with the BglII RFLP at the alpha 2 exon 1 (P = 0.02) and with the alpha 2 8.0 kb/4.3 kb haplotype (P = 0.04) and (b) linked with the beta gene MspI marker (P = 0.04) and with the beta 5.3 kb/5.1 kb haplotype (P = 0.008) based on sib-pair analysis. The present study suggests that the genes encoding Na,K-ATPase may be associated or linked with RQ and perhaps with %FAT but not with RMR.

Adipose Tissue↗
PubMed1994

Thyroid hormones and thyrotropin variations during long term overfeeding in identical twins.

The aim of this study was to evaluate variations in plasma thyroid hormones and TSH during a standardized long term overfeeding protocol (4.2 megajoules/day [corrected] during a 100-day period) in 24 lean adults (12 pairs of monozygotic twins) and to assess their relationships with body composition and resting metabolic rate (RMR) changes. Compared to preoverfeeding values, basal plasma T3 concentrations were increased on day 25, but not later; basal plasma T4 and free T4 (FT4) concentrations were unchanged; basal plasma rT3 concentrations were persistently decreased throughout the entire protocol; and the TSH response to TRH stimulation was persistently enhanced. The TSH response to TRH before overfeeding was positively correlated with the changes in RMR with overfeeding (r = -0.53; P < 0.01). No association was found between changes in basal plasma T3 concentrations and changes in RMR. However, changes in basal T3 were positively related to changes in body weight (r = 0.46; P < 0.05). A significant within-pair similarity was found for changes in T4 and FT4 with overfeeding (P < 0.05). We conclude that 1) during overfeeding, the early increase in T3 concentrations is a transitory phenomenon, whereas the decrease in rT3 concentrations and the increased TSH response to TRH are more sustained; 2) the TSH responsiveness to TRH stimulation could be a predictor of the changes in RMR during times of increased energy intake; 3) there is no evidence for a direct role of T3 in the adaptation of resting energy expenditure during a long term overfeeding protocol; and 4) the genotype could be involved in the changes in T4 and FT4 during a prolonged positive energy balance period.

Adult↗