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Biomedical subjects

C Bouchard

Publications and source records attributed to C Bouchard.

At least 505 records · Page 28Linked to original sources
PubMed1989

Impact of dietary fat content and fat oxidation on energy intake in humans.

Three studies were performed to assess the effects of a high-fat diet and exercise-induced changes in fat oxidation on energy intake in humans. In the first study the short-term effect of a high-fat diet on spontaneous energy intake was investigated. The second study evaluated the long-term effect of a high-fat diet on adiposity and the third study evaluated the effect of exercise-induced changes in fat oxidation on short-term regulation of energy intake when subjects were consuming a high-fat diet. The results of these studies indicate that a high-fat diet induces a short-term hyperphagia, a high percentage of lipids in the usual diet is associated with a higher adiposity, and exercise may attenuate or amplify the high-fat, diet-induced hyperphagia, depending on the magnitude of the exercise-induced increase in fat oxidation.

Adaptation, Physiological↗
PubMed1989

Genetic and environmental influences on level of habitual physical activity and exercise participation.

In order to quantify genetic and environmental determinants of physical activity level, 1,610 subjects from 375 families who lived in the greater Québec city area completed a three-day activity record in 1978-1981. Level of habitual physical activity, which includes all the usual activities of life, and exercise participation, which includes activities requiring at least five times the resting oxygen consumption and more, were derived from this record. Familial correlations were computed in several pairs of biologic relatives and relatives by adoption after adjustment for the effects of age, sex, physical fitness, body mass index, and socioeconomic status, and analyzed with a model of path analysis that allows the separation of the transmissible effect between generations (t2) into genetic (h2) and cultural (b2) components of inheritance. The transmission was found to be statistically significant, but was accounted for by genetic factors for level of habitual physical activity (t2 = h2 = 29%), and by cultural factors for exercise participation (t2 = b2 = 12%). Although non-transmissible environmental factors remain the major determinants of these two physical activity indicators in this population, the results suggest that children can acquire from their parents certain customs regarding exercise behavior and that the propensity toward being spontaneously active could be partly influenced by the genotype.

Activities of Daily Living↗
PubMed1989

Mitochondrial DNA polymorphism detected with the restriction enzymes BstNI and BclI in a French Canadian population.

The enzymes BstNI and BclI were used to detect various human mitochondrial DNA RFLPs in a sample of 104 unrelated French Canadians. These sequence variations were found in total white blood cell DNA probed with whole human mitochondrial DNA. With BstNI, 6 mitochondrial DNA restriction patterns (morphs) were identified. BstNI morphs 2-6 each differ from morph 1 by one single distinct restriction site gain or loss on the mitochondrial DNA molecule. Although BstNI morph 1 was found in most of the subjects (80%), each other morph was observed at a frequency of at least 3%. With the enzyme BclI, 4 different morphs were detected. Morphs 2-4 also result from different single restriction site alteration as compared with BclI morph 1. The morph 1 was clearly the most frequent (95%) while morphs 3 and 4 were present in only 1% of the subjects. These data indicate that the enzyme BstNI and, to a much lesser extent, the enzyme BclI detect mitochondrial DNA polymorphism in Caucasians. They are therefore of interest for population genetics studies.

Canada↗
PubMed1989

The effect of prior exercise and caffeine ingestion on metabolic rate and hormones in young adult males.

The purposes of this study were to examine (a) the effects of acute exercise on metabolic rate 24 and 48 h postexercise and (b) the interaction of acute exercise and the thermic effect of caffeine on metabolic rate and hormonal changes during the late postexercise recovery period. In six young males, who were regular consumers of caffeine, resting energy expenditure was measured before and after caffeine (5 mg.kg-1) and placebo ingestion under the following conditions: (i) control (e.g., no prior exercise), (ii) 24 h postexercise, and (iii) 48 h postexercise. Blood samples were drawn for plasma glucose, insulin, glycerol, free fatty acids, catecholamines, and thyroid hormones (triiodothyronine, thyroxine, and free thyroxine). Results showed that acute exercise did not exert a detectable effect on resting metabolic rate in the late postexercise recovery period, that is, resting metabolic rate was similar among the conditions of control (1.17 +/- 0.12 kcal.min-1), 24 h postexercise (1.16 +/- 0.12), and 48 h postexercise (1.16 +/- 0.11). Caffeine ingestion increased metabolic rate (approximately 7%), but the thermic effect was not different among the experimental conditions. Plasma insulin and norepinephrine were lower after caffeine ingestion, whereas an increase in plasma free fatty acids was noted. Other hormones and substrates did not change significantly in response to caffeine ingestion. Furthermore, the hormonal and substrate milieu was not significantly different 24 and 48 h postexercise when compared with the control condition. Our results support the view that acute exercise does not alter the resting metabolic rate in the late postexercise recovery period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Human variation in skeletal muscle fiber-type proportion and enzyme activities.

The purpose of the present study was to describe the extent of the variation in some of the common characteristics of human skeletal muscle. A total of 418 biopsies was obtained from the vastus lateralis muscle of 270 healthy sedentary and 148 physically active individuals of both sexes. The lowest and highest proportion of type I muscle fiber observed were 15 and 85%, respectively. Coefficients of variation (CV) reached approximately 30% for the proportion of types I and IIA fibers and were two times higher for the proportion of type IIB fiber. The smallest and largest mean muscle fiber cross-sectional areas (CSA) were approximately 1,100 microns 2 and 9,500 microns 2, respectively. Mean CSA of the various fiber types exhibited CV of approximately 23%. CV reached 30% for the activity of creatine kinase, ranged between 28 and 41% for the glycolytic enzyme markers, and between 34 and 44% for the aerobic-oxidative enzyme markers. The mean proportion of type I fiber was lower in male than in female muscles, whereas the mean CSA of all fiber types was smaller in female than in male muscles. Levels of glycolytic enzyme markers were higher in male than in female skeletal muscles. However, activities of aerobic-oxidative enzyme markers were similar in males and females. These results reveal the existence of large interindividual variability and gender differences in the most common characteristics of the human skeletal muscle.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1989

Muscle genetic variants and relationship with performance and trainability.

Samples were obtained in a maximum of 295 males and females from the vastus lateralis muscle and proteins fractionated by thin-layer isoelectric focusing. Muscle creatine kinase (CKM) and adenylate kinase (myokinase) (AK1M) were studied for the presence of variants. Six individuals exhibited a CKM variant described here for the first time, for a frequency of the variant gene of 1%. For AK1M, 21 individuals were heterozygotes for an inherited variant protein, an allele frequency of 3.5%. CKM (N = 5) and AK1M (N = 18) variant individuals were paired with control subjects who had the common CKM or AK1M muscle phenotype and compared for several performance indicators. There was no significant difference between the CKM and AK1M common and variant phenotypes for any of the performance measurements. However, the CKM variant subjects tended to be more effective than controls in a 90-min performance test (by about 22%) and had less percent decline over 60 s in force generation (by about 26%). In a subsequent experiment, a few variant subjects could be compared to controls in terms of response to exercise training. Although trends were observed, the CKM and AK1M variant subjects had a response to training generally comparable to that of the nonvariant individuals. While human variation in performance and trainability cannot be accounted for by the genetic polymorphism of the two kinase enzymes, the trends in the data suggest that allelic variation at these two gene loci may be of some functional significance.

Adenylate Kinase↗
PubMed1989

Role of deep abdominal fat in the association between regional adipose tissue distribution and glucose tolerance in obese women.

Computed tomography (CT) was used to study the association between adipose tissue localization and glucose tolerance in a sample of 52 premenopausal obese women aged 35.7 +/- 5.5 yr (mean +/- SD) and with a body fat of 45.9 +/- 5.5%. Body-fat mass and the body mass index (BMI) were significantly correlated with plasma glucose, insulin, and connecting peptide (C-peptide) areas after glucose (75 g) ingestion (.40 less than or equal to r less than or equal to .51, P less than .01). Trunk-fat accumulation and the size of fat cells in the abdomen displayed highly significant correlations with postglucose insulin levels. The C-peptide area was also positively correlated with abdominal fat cell size (r = .76, P less than .01) and was more closely associated with the sum of trunk skin folds (r = .59, P less than .001) than with the extremity skin folds (r = .29, P less than .05). Subcutaneous and deep-abdominal-fat areas measured by CT displayed comparable associations with the plasma insulin area (r = .44 and .49, respectively; P less than .001) but marked differences in the associations with glucose tolerance. Indeed, subcutaneous abdominal fat was not significantly correlated with the glucose area, whereas deep abdominal fat showed a significant correlation (r = .57, P less than .001) with the glucose area. Midthigh fat deposition measured by CT was not, however, correlated with plasma glucose, insulin, or C-peptide areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1989

[Struggling against poverty or its effects ? Early intervention programs.].

This article looks at poverty from the point of view that it does not necessarily correspond to the widespread image of chronic despair and resignation, acquired and transmitted from one generation to the next. The author argues such an image is produced by the fact that social and mental health services deal mainly with families at grips with multiple, long-standing problems. However, for most of these poor families, their condition is temporary. In fact, insufficient revenue is what distinguishes them from families that are not poor. While preventive programs show that early intervention is a proven approach towards considerably improving the psycho-social development of underpriveledged children and parents, little can be said about the effect of these programs on lowering, even less on eliminating, poverty itself. For the most part, these programs emerged from a clinical approach that encouraged poverty-stricken individuals to acquire new abilities and skills. The author concludes by promoting the need for more collaboration between those people offering the programs and those people who work towards changing the conditions at the root of poverty.

English Abstract↗
PubMed1989

Relation of high plasma triglyceride levels associated with obesity and regional adipose tissue distribution to plasma lipoprotein-lipid composition in premenopausal women.

Abdominal obesity is associated with high plasma triglyceride (TG) and with low plasma high density lipoprotein (HDL)-cholesterol (CHOL) levels. As plasma TG and HDL-CHOL are negatively correlated, the associations between obesity, the regional distribution of body fat, plasma TG levels, and plasma lipoprotein concentration and composition were studied in a sample of 76 premenopausal women (52 obese and 24 non-obese). Obese women had significantly higher plasma levels of VLDL-TG, low density lipoprotein (LDL)-CHOL, LDL-TG, LDL-apolipoprotein (apo) B and reduced HDL-CHOL levels compared to non-obese controls (p less than 0.01). However, plasma concentrations of HDL-apo A-I and HDL-TG were not different between obese and non-obese women. Partial correlation analyses revealed that both fat mass and abdominal fat accumulation significantly contributed to VLDL-TG and HDL-CHOL variances. After control for body fat mass, the waist-to-hip circumference ratio (WHR) remained significantly correlated with plasma LDL-apo B levels and with the LDL-apo B/LDL-CHOL ratio (0.01 greater than p less than 0.05). Body fat mass was, however, associated with TG enrichment of LDL (p less than 0.01). After control for WHR, body fat mass showed no significant association with plasma HDL-TG levels, whereas the WHR was positively correlated with HDL-TG levels (p less than 0.05). Partial correlation analyses indicated that adjustment for fat mass or for the WHR failed to eliminate the associations between plasma VLDL-TG levels and lipoprotein lipid composition. This study emphasizes the importance of plasma VLDL-TG level as a correlate of plasma LDL and HDL lipid composition in abdominal obesity.

Adipose Tissue↗
PubMed1989

Metabolic characteristics of postobese individuals.

The metabolic characteristics of nine postobese and six lean control male individuals were investigated to identify factors potentially associated with the predisposition to become obese. The postobese subjects had been maintaining their body weight stable for at least six months following a 24.8 kg mean weight loss. Body weight, fat mass and fat-free mass were comparable to values of the control subjects. Data obtained in postobese and control subjects were also compared to those of seven obese male individuals whose mean body weight was comparable to the body weight of postobese subjects before they initiated their weight-reducing program. Resting metabolic rate (RMR) was significantly higher (P less than 0.05) in the obese than in the two other groups. Thermic effect of food and participation in physical activities were similar in the three groups of subjects. Daily energy intake tended to be higher in control subjects but not to a statistically significant extent. However, energy intake above RMR was statistically higher in control subjects than in the two other groups. As expected, fasting and postprandial plasma glucose and insulin were substantially higher in obese than in postobese and control subjects. Moreover, fasting and postprandial hyperglucagonemia was observed in both obese and postobese subjects, suggesting that weight loss did not normalize plasma glucagon levels as was the case for glucose and insulin. From an energetic standpoint, results of the present study suggest that people predisposed to obesity may be characterized by reduced energy needs over resting metabolic rate, a phenomenon that would not be explained by a reduced physical activity level.

Blood Glucose↗
PubMed1989

Evidence for the existence of small eaters and large eaters of similar fat-free mass and activity level.

The objective of this study was to identify individuals of the same age, sex, activity level and fat-free mass who differed in their level of energy intake (EI). Estimates of energy intake and physical activity level were derived from three-day food and activity records from 430 individuals 17-54 years of age. Body composition was measured by underwater weighing and body fat and fat-free mass were obtained. Subjects were grouped into four categories based on age and sex (females aged 17-34 and 35-54 years and males aged 17-34 and 35-54 years). Subjects were identified as small eaters (SE) or large eaters (LE) according to kJ of EI per kg body weight, SE being from the lower quartile and LE from the upper quartile of their distributions. The results showed that, on average, LE consumed almost twice as many kJ per kg body weight as SE (about 200 versus 100). In addition middle-aged male and female SE were significantly (P less than 0.001) heavier than middle-aged male and female LE respectively. The mean body weight for the male SE was 82 +/- 12 kg (mean +/- s.d.) against 69 +/- 9 kg for the LE, while it was 66 +/- 10 kg against 52 +/- 5 kg for the female SE and LE. The male and female SE also had a significantly higher percentage body fat in both age groups. In general, there was no difference in fat-free mass and activity level between the SE and LE. It is concluded that there exist groups of individuals who have a considerable difference in their EI and adiposity even though they have similar levels of activity and fat-free mass.

Activities of Daily Living↗
PubMed1989

Validity of anthropometry in classifying youths as obese.

Using densitometrically-determined percentage body fat as the criterion of true obesity, 316 youths aged 8.4-18.99 years were classified as obese or not obese using conventional referent values for five anthropometric indicators of obesity (weight, BMI, triceps skinfold, subscapular skinfold and percent body fat estimated from the sum of four skinfolds). Estimates of sensitivity, specificity, predictive value and efficiency were used to describe the relative validity of the anthropometric indicators, and the nature of misclassification resulting when the indicators were applied. The indicators were characterized generally by low levels of sensitivity and corresponding high rates of false negatives, i.e. truly obese youths who were considered not obese by the indicators. Although indicators had high specificities, there were significant differences among indicators. The general pattern of high specificity is desirable, given the nature of obesity in youths. Using the validity criteria and conventional referent values, triceps skinfold thickness in boys and BMI in girls are the preferred single anthropometric indicators of obesity in youths.

Adolescent↗
PubMed1989

Cardiovascular risk factors in a French-Canadian population: resolution of genetic and familial environmental effects on blood pressure by using extensive information on environmental correlates.

Genetic and environmental influences on systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial blood pressure (MBP) were examined in 371 French-Canadian families by using path analysis. Familial environment was estimated with environmental indices constructed from as many as 14 (of a pool of more than 100) correlates of blood pressure (BP). Approximately 20% of the variance in BP can be accounted for by the composite index, and the types of variables and the direction of their effects vary as a function of age and of the multivariate context. Path analysis of the family data suggests that genetic heritability is relatively high in children (from 0.49 for SBP to 0.56 for MBP) but much smaller in adults (from 0.08 for DBP to 0.18 for SBP). The proportion of variability explained by familial environment is estimated to be the same in children and adults and is much higher than reported to date (from 0.30 for SBP to 0.42 for DBP). In addition, sibships share significant nontransmitted environmental effects, and there is no evidence to suggest specific maternal effects in the aggregation of BP. Two unique findings emerge from this study. First, unlike in most earlier studies, we were able to arrive at the same parsimonious model for each of the BP variables. Second, the familial environment accounts for a substantial proportion of the variability in BP, which has been considerably underestimated in earlier studies.

Blood Pressure↗
PubMed1989

Anaerobic performances of sedentary and trained subjects.

The objective of this report was to compare the performance of sedentary individuals, physical education students, and athletes of various disciplines in 10 s and 90 s maximal cycle ergometer tests. The 10 s power was the highest power output in one second from the 10 s test, while capacities were defined as the total work output during the best 10 s trial and the 90 s test. ANOVA and Duncan multiple range test indicated that the mean values of the 10 S power and capacity and the 90 S capacity tests were significantly higher in sprinter than in sedentary groups. Sprinters performed significantly better than marathon runners only in the 10 s capacity and power. Bodybuilders and sedentary subjects had similar results in the 90 s capacity test. Mean performance values per kilogram of body weight in sedentary females reached about 60% of sedentary males while marathon runners, physical education students and sprinter females reached about 80% of the male performances for the three indicators. When expressed per kilogram of fat-free mass, females reached a higher proportion of the male values for all performances. These results indicate that: a) there are differences for the power and capacity measured in predominantly anaerobic tests between athletes from different disciplines and sedentary individuals, and b) gender differences exist for these anaerobic performance indicators, but they appear attenuated in trained subjects.

Adipose Tissue↗
PubMed1988

A colposcopical lesion of the uterine cervix frequently associated with papillomavirus type 16 as detected by in situ and Southern blot hybridization: a cytohistological correlation study.

A convoluted aceto-white lesion was observed by colposcopy on the uterine cervix of 19 patients. A search for specific types of papillomavirus was undertaken in these lesions which proved histologically to be a vertical association of CIN in the lower strata of the squamous epithelium and typical condyloma in the uppermost layers. Previous cell samples correlated with histology in only 11 out of the 19 cases, and were not therefore an accurate predictor of histologic findings. However 16 out of our 19 cases had sufficient cellular changes to warrant colposcopy and biopsy. Papillomavirus capsid antigen was detected by peroxidase-antiperoxidase staining technique in 12 out of the 19 cases (63.1%). In situ hybridization using biotinylated HPV-16 DNA probes was positive in 13 out of 18 cases (72.2%). Southern blot hybridization gave the typical PstI pattern of HPV-DNA in 8 out of 9 cases examined. The detection of HPV-DNA and HPV capsid antigen was particularly high in this "convoluted" cervical lesion, suggesting that the virus remains biologically active. It may therefore be assumed that this lesion represents a particular phase of the disease process in which early gene function and late gene expression of the viral genome are markedly manifested. Furthermore, this lesion may well represent a link between the early manifestation of HPV infection (condyloma) and CIN, which constitute a morphologic continuum initiated by papillomaviruses.

Adolescent↗