Search PubMed⌕ Search

Biomedical subjects

C Bouchard

Publications and source records attributed to C Bouchard.

At least 325 records · Page 18Linked to original sources
PubMed1996

[Severe burnt patients: hemodynamic state, oxygen transport and consumption, plasma cytokines].

OBJECTIVE: To assess the haemodynamic and oxymetric variations measured by a pulmonary artery catheter and to correlate them with the variations of the circulating cytokines during the initial intensive care phase of severely burned patients. STUDY DESIGN: Prospective study covering an 18-month period. PATIENTS: Thirteen successive patients, aged over 12 years, without significant medical history, with a thermal burn affecting more than 50 percent of their total body surface area and admitted to our centre during the first six postburn hours. METHODS: The haemodynamic and oxymetric profile was investigated by inserting a blood flow-directed balloon-tipped pulmonary artery fiberoptical catheter. All patients were treated according to the protocol previously used in our centre. Blood samples were drawn on admission, every 12 hours post-injury until the 2nd day, then on the 3rd and 5th days. Cytokines were analyzed by Elisa method. Haemodynamic and oxymetric measurements were achieved simultaneously with the biological samples during the first 5 postburn days. The analysis of variance (ANOVA) with the Duncan test was utilized for multiple comparisons between continuous variables. RESULTS: (mean +/- SEM): The patients were 32 +/- 3 years-old and had a burn surface of 72 +/- 4%. After a short hypovolemic shock period lasting a 12 hours, a hyperdynamic shock occured which increased until the 5th day, with an increased cardiac index (6.9 +/- 0.4 at h120 vs 2.9 +/- 0.3 L.min-1.m-2 at h6, P < 0.05), increased oxygen transport and consumption (respectively 880 +/- 77 at h72 vs 543 +/- 58 mL.min-1 at h12, P < 0.05 and, 203 +/- 15 at h72 vs 129 +/- 25 mL.min-1 at h6, P < 0.05) and markedly decreased systemic vascular resistances (1,002 +/- 118 at h36 vs 2,330 +/- 328 dyn.s.cm-5.m2 at h6, P < 0.05). Circulating cytokines were not clearly modified except for interleukine-6 which reached early striking peaks (16,858 +/- 10,330 at h24 and 15,406 +/- 6,509 pg.mL-1 at h36) simultaneously with the decrease in systemic vascular resistances. CONCLUSIONS: During the first post-injury week, critically burned patients develop a specific hyperdynamic circulatory status during which interleukine-6 could be a mainfactor decreasing systemic arterial resistances.

Adult↗
PubMed1996

Plasma high-density lipoprotein cholesterol but not apolipoprotein A-I is a good correlate of the visceral obesity-insulin resistance dyslipidemic syndrome.

Apolipoprotein (apo) A-I is a major component of high-density lipoproteins (HDLs), and it has been suggested that measurement of apo A-I may provide additional information in the assessment of coronary heart disease (CHD) risk. In the present study in a sample of 111 men (age [mean +/- SD], 35.3 +/- 6.6 years), we determined whether a low apo A-I concentration is associated with the cluster of metabolic abnormalities that characterize the visceral obesity-insulin resistance dyslipidemic syndrome. For this purpose, the first and fourth quartiles of apo A-I and HDL cholesterol (HDL-C) concentrations were compared in relation to body fat distribution, glucose tolerance, and plasma insulin and lipoprotein levels. Men in the first quartile (< the 25th percentile) of HDL-C, as compared with men in the fourth quartile (> the 75th percentile), were characterized by an elevated visceral adipose tissue (AT) accumulation (P < .05), as well as by increased plasma levels of triglycerides ([TGs] P < .0001), apo B (P < .0005), and insulin (P < .01). These differences were not found when the first and fourth quartiles of plasma apo A-I concentrations were compared. These results suggest that plasma levels of HDL-C are more closely associated with the various features of the visceral obesity-insulin resistance syndrome than plasma apo A-I.

Adipose Tissue↗
PubMed1996

Overfeeding in identical twins: 5-year postoverfeeding results.

From a total of 12 pairs of young male identical twins who were overfed by an estimated 84,000 kcal over a period of 100 days, several pairs (eight to 11, depending on variables) were remeasured for body weight, body composition with the underwater weighing technique, regional fat distribution from skinfolds, girths, computed tomography (CT) fat areas in the abdominal region, and fasting plasma glucose, insulin, total cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides 4 months and 5 years after completion of the overfeeding protocol. At 4 months, the twins had lost approximately 7 of 8 kg that they had gained with overfeeding. However, 5 years later, body weight had increased by 5 kg over the preoverfeeding level. Fluctuations in fat mass were greater than those in fat-free mass. The younger twins gained approximately twice as much as the older twins in the late recovery period, a difference attributed to the late phase of growth in body mass in the former. Upper-body fat was reduced at 4 months of follow-up study, but was increased in the late recovery phase. All blood values were normalized in the postoverfeeding periods. A within-pair resemblance was generally observed for the changes noted in the recovery periods, but it was more striking when variations between preoverfeeding and 4-month or 5-year values were considered. We conclude from these observations that there were no persistent effects of exposure to the overfeeding protocol over the expected age-associated increases in body mass, body fat, upper-body fat, abdominal visceral fat (AVF), and metabolic variables predictive of risk for common diseases in individuals of normal body weight and with no family history of obesity. The intrapair resemblance suggests that the genotype contributes to the alterations observed in the recovery from overfeeding and in the age-associated changes.

Adipose Tissue↗
PubMed1996

Familial aggregation of abdominal visceral fat level: results from the Quebec family study.

The purpose of this study was to investigate the importance of familial aggregation in abdominal visceral fat (AVF) level as assessed by computed tomography (CT). Four measures of abdominal adipose tissue, obtained from an abdominal scan between the fourth and fifth Lumbar vertebrae (L4-L5) taken in 366 adult subjects from 100 French-Canadian nuclear families, were considered in this study. Total abdominal fat, AVF, subcutaneous abdominal fat, obtained by computing the difference between total and AVF tissue areas, and the visceral to total abdominal fat ratio were measured. Spouses, parent-offspring, and sibling correlations were computed by maximum likelihood methods after adjustment of the four phenotypes for age and for age and total fat mass (FM) derived from underwater weighing. Significant familial aggregation was found for all phenotypes, whether adjusted or not for body FM. However, after adjustment of data for body FM, in addition to age, all spouse correlations became nonsignificant, suggesting that the familial aggregation of abdominal fat is primarily genetic. Heritability estimates reached 42% and 56% for subcutaneous fat and AVF, respectively. These results suggest that genetic factors are major determinants of the familial aggregation observed in the amount of abdominal fat, irrespective of total body fat content, and that AVF seems more influenced by genetic factors than abdominal subcutaneous adipose tissue. These findings imply that some individuals are more at risk than others to exhibit the various metabolic complications associated with upper-body obesity because of their inherited tendency to store abdominal fat in the visceral depot rather than in the subcutaneous depot.

Abdomen↗
PubMed1996

The HERITAGE Family Study: quality assurance and quality control.

The HERITAGE (HEalth, RIsk factors, exercise Training And GEnetics) Family Study is the first multicenter family clinical trial of its kind. Conducted by a consortium of five universities in the United States and Canada, the study has as its primary goal to document the role of the genotype in the cardiovascular, metabolic, and hormonal responses to aerobic exercise training. A comprehensive protocol was implemented at four Clinical Centers (CC) for the generation of data on sedentary subjects. This group included 450 caucasians from 90 nuclear families (father, mother, three children) and 200 black subjects from 40 to 100 family units over a 5-year period. The entire family was tested before and after a 20-week exercise training program. The fifth participating center, the Data Coordinating Center (DCC), is responsible for data management and data analysis. A Consortium Coordinating Center (CCC) responsible for the overall coordination and direction of the study was established at the Quebec CC. Quality assurance and quality control are jointly coordinated by the CCC and the DCC. A multicenter study of this magnitude requires careful standardization of all procedures and constant monitoring of quality control at all levels of operation. This report describes the quality assurance and quality control measures implemented in the HERITAGE Family Study, including some examples with real data.

Adolescent↗
PubMed1996

A single threshold value of waist girth identifies normal-weight and overweight subjects with excess visceral adipose tissue.

Our objective was to determine threshold values of waist girth, waist-to-hip ratio (WHR), and sagittal diameter corresponding to an accumulation of visceral adipose tissue of 130 cm2 and to verify whether these threshold values could be influenced by sex, age, menopausal status, and the degree of obesity. From the regression equations computed in the total sample of 213 men [aged (mean+/- SD) 37.8 +/- 12.2 y] and 190 women (aged 37.3 +/- 12.1 y), a waist girth of approximately 95 cm in both sexes, WHR values of 0.94 in men and of 0.88 in women, and sagittal diameters of 22.8 cm in men and 25.2 cm in women corresponded to a visceral adipose tissue area of 130 cm2. In both sexes, threshold values of waist girth corresponding to critical amounts of visceral adipose tissue were generally lower in subjects who were > or = 40 y old (approximately 90 cm) than in younger individuals (approximately 100 cm). Similar differences were found for WHR and sagittal diameter threshold values. Finally, threshold values of waist girth corresponding to critical amounts of visceral adipose tissue were essentially similar in normal-weight and overweight men and women, whereas threshold values of WHR were in general higher in normal-weight than in overweight subjects. In conclusion, our results suggest that the relations of anthropometric variables to visceral adipose tissue accumulation are age-specific. However, waist girth is likely to be a more convenient anthropometric correlate of visceral adipose tissue than the WHR because threshold values of waist girth corresponding to critical amounts of visceral adipose tissue do not appear to be influenced by sex or by the degree of obesity.

Adipose Tissue↗
PubMed1996

Determinants of persistent detection of human papillomavirus DNA in the uterine cervix.

To identify factors associated with persistence of human papillomavirus (HPV) DNA in the uterine cervix, 179 women who were 18-49 years old and who had normal cytologies and positive cervical HPV DNA test at a routine periodic examination were analyzed. Among them, 91 (50.8%) remained HPV-positive a few months (mean, 11 weeks) later. Persistence was higher in women who had used oral contraceptives for > or = 2 years (odds ratio, 3.9; 95% confidence interval, 1.5-10.3) compared with those who never used oral contraceptives or used them for <2 years. HPV types 16, 18, and 31/33/35 appeared more persistent (odds ratio, 2.5; 95% confidence interval, 1.0-6.2) than other types. Persistence seemed to increase with virus load and decrease with increasing interval between examinations.

Chronic Disease↗
PubMed1996

Endurance exercise training has a minimal effect on resting heart rate: the HERITAGE Study.

This study determined the effects of a 20-wk endurance training program (The HERITAGE Family Study) on resting heart rate (HRrest). HRrest was obtained on a sample of 26 men and 21 women during sleep; during resting metabolic rate and resting blood pressure measurement periods in the early morning following a 12-h fast and 24-h post-exercise; and at rest prior to a maximal bout of exercise. Following training, the subjects exhibited a 16.0 +/- 9.4% (mean +/- SD) increase in VO2max (P < 0.05), but the HRrest for each of the resting conditions was decreased by only 1.9 to 3.4 bpm (P < 0.05), or an average across the three conditions of 2.7 bpm. In a larger sample of 253 HERITAGE subjects, HRrest obtained only at the time of the resting blood pressure measurement decreased by only 2.6 bpm, while VO2max increased 17.7 +/- 10.0%. It is concluded that there is a significant, but small, decrease in resting heart rate as a result of 20 wk of moderate- to high-intensity endurance training; which suggests a minimal alteration in either, or both, intrinsic heart rate and autonomic control of HRrest.

Adolescent↗
PubMed1996

Associations between health behaviours and health related fitness.

OBJECTIVE: To examine relations between health behaviours and health related fitness. METHODS: Subjects were a convenience sample of 350 healthy adults (172 men, 178 women). Covariance analysis adjusted data for significant influences of age and socioeconomic status. Obesity was assessed by anthropometry and body density. Cardiovascular fitness was assessed and various metabolic measurements were made. Questionnaires on physical activity and health related behaviours were completed. RESULTS: Cigarette abstinence was associated with a small abdominal circumference (men) and a low trunk/extremity skinfold ratio (women). Obesity indices (body mass index, total skinfolds, percent fat, and abdominal circumference) were negatively associated with perceived fitness. Leisure activity and exercise frequency were also negatively linked to some obesity indices. Blood glucose, cholesterol, HDL-cholesterol, and triglycerides were favourably influenced by perceived activity, exercise frequency, and perceived fitness, but not by exercise intensity. Abstinence from coffee was associated with a low cholesterol/HDL ratio (men only). Principal component, discriminant, and multiple logistic regression analyses showed only weak clustering of habitual physical activity with other positive health behaviours. CONCLUSIONS: Although multiphasic health promotion programmes are economical, favourable interactions between individual programme elements seem likely to be quite limited.

Adolescent↗
PubMed1996

Reproducibility of 24-h energy expenditure and macronutrient oxidation rates in an indirect calorimeter.

The maintenance of weight and adipose tissue mass in humans appears to be related to a balance between the rates of oxidation and consumption of macronutrients; yet, little evidence is available on the reproducibility of 24-h macronutrient oxidation rates and how this relates to diet in the days preceding a chamber session. This study examined the reproducibility of 24-h macronutrient oxidation rates, 24-h energy expenditure (EE), and respiratory quotient (RQ) in 30 adults who ate their habitual diets before two 24-h whole body indirect calorimeter sessions. Results showed that the within-subject coefficients of variation (CVws) for 24-h EE and RQ were 2.8 and 2.6%, respectively. CVws for macronutrient oxidations ranged from approximately 15 to 25%. Means comparisons of 24-h EE, RQ, and macronutrient oxidation rates between sessions showed no significant differences, and all variables had significant positive intraclass correlation coefficients (P < 0.05). In conclusion, macronutrient oxidations all showed significant reproducibility for the group and a significant but lower reproducibility for individuals when habitual diet and activity preceded the experimental sessions.

Adipose Tissue↗
PubMed1996

The apoB-100 gene EcoRI polymorphism influences the relationship between features of the insulin resistance syndrome and the hyper-apoB and dense LDL phenotype in men.

The aim of this study was to investigate whether the EcoRI polymorphism of the apolipoprotein B (apoB) gene influences the relationships between features of the insulin resistance syndrome and the dense LDL phenotype and apoB concentrations. A sample of 65 men was divided into two groups on the basis of the EcoRI genotype. Forty-four subjects were (+/+) homozygotes for the presence of the EcoRI restriction site that is associated with a glutamic acid at codon 4154. Twenty-one men were (+/-) heterozygotes for the absence of the restriction site resulting from a glutamic acid to a lysine substitution at codon 4154. In the (+/-) group, fasting plasma FFA levels were positively correlated with plasma apoB, LDL-apoB, and the LDL particle score that was calculated from the migration distances of LDL subspecies and their relative band intensities, reflecting the proportion of small dense LDL particles. However, these associations were not found among (+/+) subjects. The two genotypic groups were further divided into two subgroups on the basis of fasting FFA concentrations, and the LDL particle score and the LDL-apoB levels were compared. High FFA levels were associated with a higher proportion of small dense LDL particles, as reflected by a higher mean LDL particle score, irrespective of the genotype. However, the apoB-EcoRI polymorphism appeared to influence the association between high FFA levels and LDL-apoB concentrations because (+/-) heterozygotes with high FFA levels had higher LDL-apoB concentrations than (+/-) heterozygotes with low FFA levels. In addition, the integrated area under the curve of plasma insulin concentrations, measured in response to a 75-g oral glucose challenge, and the amount of visceral adipose tissue, measured by computed tomography, were positively associated with the LDL particle score only in (+/-) heterozygotes. When subjects were divided on the basis of insulin area (low vs. high) or visceral adipose tissue (low vs. high), (+/-) heterozygotes with high insulin area or with high levels of visceral adipose tissue had a higher mean LDL particle score than (+/-) heterozygotes with low insulin area or low visceral adipose tissue. However, among (+/+) homozygotes, low or high levels of insulin or visceral adipose tissue could not discriminate between men with large or small LDL particles. Therefore, (+/-) heterozygotes may be more susceptible to develop the dense LDL phenotype in presence of hyperinsulinemia and visceral obesity. Results of the present study suggest that the apoB-EcoRI polymorphism may exacerbate the alterations in the LDL particle (size and concentration) found among visceral obese-hyperinsulinemic men.

Adipose Tissue↗
PubMed1996

Seven-year changes in body fat and visceral adipose tissue in women. Association with indexes of plasma glucose-insulin homeostasis.

OBJECTIVE: To study the associations between changes in body fatness, visceral adipose tissue (AT), and indexes of plasma glucose-insulin homeostasis over a 7-year follow-up period. RESEARCH DESIGN AND METHODS: A sample of 30 nondiabetic women aged 35.2 +/- 5.6 (SD) years at baseline was studied. RESULTS: Changes in visceral AT and in subcutaneous AT (measured by computed tomography) as well as changes in body fat mass (obtained by hydrostatic weighting) were significantly related to changes in fasting plasma insulin levels and in plasma insulin area measured after a 75-g oral glucose load (0.47 < or = r < or = 0.62; P < 0.01). Changes in visceral AT but not in body fat mass or in subcutaneous AT area were significantly associated with changes in plasma glucose area (r = 0.37; P < 0.05). When two subgroups of women with similar mean increases in body fat mass but with either small or large increases in visceral AT were compared, the subgroup with the largest gain in visceral AT showed the greatest deterioration in indexes of plasma glucose-insulin homeostasis. On the other hand, when two subgroups with similar mean increases in visceral AT but with different changes in body fat mass were compared, both subgroups showed similar changes in plasma glucose and insulin concentrations. CONCLUSIONS: Results of this 7-year follow-up study in women suggest that changes in indexes of plasma glucose-insulin homeostasis are significantly associated with changes in visceral AT, even after control for changes in body fat mass.

Adipose Tissue↗
PubMed1996

The Bcl I polymorphism of the human uncoupling protein (ucp) gene is due to a point mutation in the 5'-flanking region.

The polymorphic Bcl I site in the human ucp gene associated to percentage fat gain over time in the Québec Family Study cohort (Oppert et al. Int J Obesity 1994; 18: 526-531) has been positioned to the 5'-flanking region. This polymorphism results from a unique A/G mutation. Oligonucleotides used to amplify the polymorphic region, and allowing future studies of any cohort of patients, are described.

Base Sequence↗
PubMed1996

Major gene for abdominal visceral fat area in the Québec Family Study.

OBJECTIVES: The abdominal visceral fat depot is considered to be the most atherogenic, diabetogenic and hypertensiogenic fat depot of the human body. Although the amount of abdominal visceral fat is correlated with total body fat, there remain considerable inter-individual differences in visceral fat at any level of body fat content. No study has been reported to date on the contribution of genetic factors to the variability in abdominal visceral fat level. DESIGN: Abdominal visceral fat area was assessed by computerized tomography in 382 adult men and women from 100 families of the Québec Family Study. After adjustment for the effects of age and age plus total fat mass (assessed by underwater weighing), a major gene hypothesis for abdominal visceral fat area was investigated using segregation (POINTER) analyses. RESULTS: Segregation analysis of the age-adjusted variable indicated that variability in visceral fat area was accounted for by a major gene transmitted according to Mendelian expectations. Data support an autosomal recessive locus, associated with high levels of abdominal visceral fat, accounting for 51% of the phenotypic variance and affecting 10% of the sample. An additional 21% of the variance was due to multifactorial (polygenic and/or familial environment) sources. However, after adjusting for total fat mass, support for a major gene for abdominal visceral fat was less strong. CONCLUSIONS: These results suggest that the familial etiology of abdominal visceral fat level involves a major autosomal recessive locus. Given the critical role of abdominal visceral fat in the metabolic complications of obesity, it will now be important to identify the gene responsible for the high levels of abdominal visceral fat observed in some adults and to investigate whether this gene is the same as that which influences total body fat content.

Abdomen↗
PubMed1996

Anthropometric correlates to changes in visceral adipose tissue over 7 years in women.

OBJECTIVE: To investigate the association between either increases or decreases in visceral adipose tissue and changes in anthropometric indices in a group of 32 women studied over a 7-y period. SUBJECTS: 32 women aged 35.1 +/- 5.4 (SD) years at baseline. MEASUREMENTS: Waist and hip circumferences, body fat mass (hydrostatic weighing) and viscera adipose tissue (computed tomography) were measured at baseline and at follow-up. RESULTS: Waist girth, waist-to-hip ratio, sagittal diameter and visceral adipose tissue area were all significantly higher at follow-up than at baseline (p < 0.05). Changes in visceral adipose tissue area were strongly correlated to changes in waist girth, hip girth, sagittal diameter and body fat mass (0.80 < or = r < or = 0.91 p < 0.0001). However, the association between changes in waist-to-hip ratio and those in visceral adipose tissue area was of low magnitude (r = 0.35; p = 0.05). Partial correlation analyses showed that the association between changes in visceral adipose tissue area and changes in either waist girth (p < 0.01) or sagittal diameter (p < 0.0001) remained significant even after control for 7-y variation in total body fatness. CONCLUSION: Results of the present study suggest that changes in visceral adipose tissue accumulation that occur with age in women are better predicted by changes in waist girth or sagittal diameter than by changes in waist-to-hip ratio.

Adipose Tissue↗