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Biomedical subjects

J Bergeron

Publications and source records attributed to J Bergeron.

At least 19 recordsLinked to original sources
PubMed2006

Disinhibition, as assessed by the Three-Factor Eating Questionnaire, is inversely related to psychological well-being in postmenopausal women.

UNLABELLED: Psychological correlates of obesity remain under controversy. As eating behaviors and dieting history have been previously related to obesity status, these dietary variables may contribute to identify overweight and obese individuals who are at higher risk of having an impaired psychological well-being. OBJECTIVE: The main purpose of this cross-sectional study was to verify the hypothesis of a relationship between weight status and psychological well-being, and to examine whether cognitive dietary restraint, disinhibition, susceptibility to hunger and dieting history could be related to psychological well-being. DESIGN AND SUBJECTS: In a sample of 101 postmenopausal women, we performed anthropometric measurements (weight, height and body mass index (BMI)), and measured psychological well-being (PER Questionnaire). The Three-Factor Eating Questionnaire (TFEQ) and a questionnaire about dieting history (dieters: had already been on a diet; non-dieters: had never been on a diet) were also administrated. RESULTS: A trend for a significant relationship was observed between BMI and psychological well-being (r=-0.17; P=0.08). Significant negative relationships were observed for disinhibition, susceptibility to hunger and all their subscales with psychological well-being (-0.28</=r</=-0.48), whereas no significant differences in psychological well-being were observed between dieters and non-dieters. Finally, women displaying a higher score for habitual susceptibility to disinhibition (which is the subscale of TFEQ that was the most closely related to psychological well-being) had a lower level of psychological well-being, regardless of their weight status. CONCLUSION: These results show that, as well as being related to weight status, TFEQ-factors are also related to psychological well-being. More specifically, individuals who display higher levels of disinhibition may be at higher risk of having an impaired psychological well-being.

Aged↗
PubMed2004

Effect of type 2 diabetes on various electrophoretic characteristics of low-density lipoprotein particles in women.

AIMS/HYPOTHESIS: Coronary heart disease represents the leading cause of death in type 2 diabetic patients. As the small, dense LDL phenotype is a typical feature of the dyslipidaemic state found in type 2 diabetes, this characteristic could be an important mediator of the elevated coronary heart disease risk in this condition. We have therefore studied the effect of type 2 diabetes on various electrophoretic characteristics of LDL particles. METHODS: Potential differences in LDL peak particle size and in concentration of LDL cholesterol in small (<255 A) and large (>260 A) LDL particles were assessed by polyacrylamide gradient gel electrophoresis among 183 non-diabetic and 56 type 2 diabetic women. RESULTS: LDL peak particle size was significantly smaller in type 2 diabetic women than in non-diabetic women (p<0.0001). In addition, the proportion of small LDL particles (<255 A) was higher in type 2 diabetic women, whereas the proportion of large LDL particles (>260 A) was lower than in non-diabetic women (p<0.0002). Type 2 diabetic women also had the highest waist circumference and triglyceride levels (p<0.03). When subgroups of non-diabetic and type 2 diabetic women were individually matched (n=41) for similar waist circumference and triglyceride levels, the differences initially found in LDL peak particle size and in the proportion of small and large LDL particles remained significantly different between the two groups (p<0.01). CONCLUSIONS/INTERPRETATION: These results provide evidence that type 2 diabetes may have an independent effect on LDL peak particle size and on the proportion of small and large LDL particles.

Blood Glucose↗
PubMed2004

Impaired fasting glucose vs. glucose intolerance in pre-menopausal women: distinct metabolic entities and cardiovascular disease risk?

BACKGROUND: Impaired glucose tolerance (IGT) is associated with an increased cardiovascular disease risk. Less is known about cardiovascular disease risk among subjects with impaired fasting glucose (IFG) or with combined IFG and IGT. AIMS: To compare body composition, body fat distribution, plasma glucose-insulin homeostasis and plasma lipid-lipoprotein profile between pre-menopausal women having either a normal glucose tolerance (NGT), isolated IFG, isolated IGT or combined IFG and IGT. METHODS: Three hundred and thirty-four women with NGT, 11 women with IFG, 35 women with IGT and 10 women with both IFG and IGT were studied. RESULTS: Women with IFG were characterized by a higher visceral adipose tissue (AT) accumulation than women with NGT (P < 0.05). Also, they were characterized by a higher subcutaneous AT area and by higher body fat mass than NGT and IGT women (P < 0.05). However, their lipid-lipoprotein profile was comparable with that of NGT women, except for reduced HDL-cholesterol concentrations (P < 0.05). After adjustment for visceral AT, women with IFG had lower total cholesterol, LDL-cholesterol and apolipoprotein B (apoB) levels than the three other groups. They also had lower HDL(2)-cholesterol than NGT women and lower total cholesterol/HDL-cholesterol ratio than IGT women. Women with IGT showed higher triglyceride and apoB concentrations and a higher total cholesterol/HDL-cholesterol ratio than women with NGT (P < 0.05). Overall, women with combined IFG and IGT showed body fatness characteristics and alterations in their metabolic risk profile which were essentially similar to women with isolated IGT. CONCLUSIONS: These results indicate that there are significant differences in anthropometric and metabolic variables between pre-menopausal women with IFG vs. IGT and that the association between body fatness-body fat distribution indices and the metabolic profile may differ between IFG and IGT women.

Adolescent↗
PubMed2004

Occurrence and significance of filamentous bacteria in pulp and paper activated sludge systems.

A microbial survey of 27 activated sludge (AS) systems included 16 conventional activated sludge (CAS) systems, five sequential batch reactors (SBR) and six oxygen-activated sludge (OAS) systems, all treating pulp and paper effluents. The most prevalent filaments observed were Thiothrix (26%) and Type 021N (22%). The designs of the activated sludge systems seemed to have an effect on the filament types. We found Thiothrix to be the most common filament associated with bulking. For CAS systems, a completely mixed mode of operation promoted Thiothrix and Type 021N growth. Type 021N was favoured in CAS systems with food to microorganism (F/M) ratios higher than 0.2, and with dissolved oxygen (DO) residuals higher than 2 ppm, while Thiothrix generally proliferated at lower F/M ratio and DO residuals. Nutrient deficiencies as well as nutrient dosage variations were suspected in most of the systems having Thiothrix and Type 021N as the most prevalent filaments. Thiothrix appeared to prefer polyphosphate and/or ammonia rather than urea/phosphoric acid as N and P sources. Systems with aerobic selectors showed the lowest filament counts, while systems with no selectors showed the highest filament counts.

Environmental Monitoring↗
PubMed2003

Post-heparin lipolytic enzyme activities, sex hormones and sex hormone-binding globulin (SHBG) in men and women: The HERITAGE Family Study.

We tested the hypothesis that androgen, estrogen, and sex hormone-binding globulin (SHBG) levels would be significantly related to post-heparin hepatic lipase (HL) and lipoprotein lipase (LPL) activities in a sample of Caucasian men (n = 233) and women (n = 235) aged 17-64 years from the HERITAGE Family Study. Body composition (hydrostatic weighing), abdominal adipose tissue distribution (computed tomography), plasma lipid-lipoprotein and hormone levels, and post-heparin lipases activities were measured. HL activity was significantly higher in males, whereas LPL activity was higher in women (P < 0.005). In women only, HL activity was positively associated with body fat mass (r = 0.17, P < 0.05) and intra-abdominal adipose tissue area (r = 0.18, P < 0.05). Significant associations were also found between fasting insulin and LPL activity (r = -0.16, P < 0.05 and r = -0.18, P < 0.005) as well as HL activity (r = 0.22, P < 0.005, and r = 0.27, P < 0.0001) in men and women, respectively. A positive association between total testosterone and HL activity was noted in men (r = 0.13, P = 0.05). In women, plasma SHBG levels were negatively associated with HL activity (r = -0.48, P < 0.0001), and statistical adjustment for body fat mass, visceral adipose tissue area, and fasting insulin did not attenuate this correlation. In multivariate analyses with models including adiposity variables and measurements of the hormonal profile, insulin, and testosterone levels were both independent positive predictors of HL activity in men. In women, hormone use was a significant positive predictor, and SHBG level a strong negative predictor of HL activity, independent of plasma estradiol and testosterone concentrations. Fasting insulin was the only significant predictor of LPL activity in men (negative association), whereas menstrual status, fasting insulin (negative associations), and plasma SHBG levels (positive association) were all independent predictors of LPL activity in women. These results suggest that the postulated sensitivity of lipolytic enzymes to androgens and estrogens is reflected by a strong negative association between SHBG levels and HL, and a lower magnitude positive association of this hormonal parameter to LPL activity in women. These associations appear to be independent from concomitant variation in total adiposity or body fat distribution.

Adipose Tissue↗
PubMed2003

Effect of obesity on HDL and LDL particle sizes in carriers of the null P207L or defective D9N mutation in the lipoprotein lipase gene: the Québec LipD Study.

BACKGROUND: We have recently demonstrated that French Canadians bearing a mutation in the lipoprotein lipase (LPL) gene present an impaired lipoprotein-lipid profile characterized by small low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particles compared with healthy subjects. It has also been documented that obesity has a significant impact on HDL and LDL particle sizes. OBJECTIVE: To examine the extent to which obesity modulates HDL and LDL particle sizes among carriers of mutations in the LPL gene. SUBJECTS: Analyses were carried out in 206 heterozygous carriers of the D9N mutation (N=118) or the P207L mutation (N=88). MEASUREMENTS: Lipoprotein particle sizes were measured on whole plasma by nondenaturing polyacrylamide gradient gel electrophoresis. RESULTS: In general, body mass index (BMI) and waist circumference were significant correlates of LDL and HDL particle sizes among heterozygous carriers of the P207L or D9N mutation in the LPL gene, with relatively similar associations among men and women. Multivariate analyses indicated that variations in waist circumference but not BMI were an independent predictor of variations in both HDL particle size (5.2%, P=0.0005) and LDL particle size (5.9%, P=0.01) in the entire group of heterozygotes for LPL mutation in a model that included the nature of the LPL mutation (D9N vs P207L), gender, age, cholesterol and plasma TG levels. Interestingly, there was a significant interaction between plasma TG levels and waist circumference or BMI in modulating HDL particle size. Indeed, an increased waist circumference or BMI was associated with a significant reduction in HDL particle size among subjects with plasma TG levels 3.5 mmol/l). CONCLUSION: These results suggest that abdominal obesity, more so that overall obesity, is an important determinant of variations in LDL and HDL particle size among heterozygous carriers of mutations in the LPL gene, perhaps further contributing to modulate the risk of CHD in these individuals.

Body Mass Index↗
PubMed2002

Influence of the angiotensin-converting enzyme gene insertion/deletion polymorphism on lipoprotein/lipid response to gemfibrozil.

Evidence suggests that fibrate therapy reduces the risk of recurrent coronary heart disease among men with low levels of high density lipoprotein cholesterol (HDL-C). Indirect observations and new possible biological pathways suggest that the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism might modulate the lipoprotein/lipid profile and its response to fibrate therapy. To assess the possible interaction between fibrate therapy and such variants on plasma lipid and lipoprotein levels, 65 dyslipidemic abdominally obese men were treated for 6 months with or without gemfibrozil (600 mg twice daily). No differences in baseline plasma lipid and lipoprotein levels were found between genotype groups except for the HDL(3)-C subfraction, which was higher in the DD group (p = 0.02). A two-way factorial ANOVA was used to evaluate the effect of the genotype (DD homozygotes vs I allele carriers), the treatment (placebo vs gemfibrozil), and the interaction between these two independent variables on changes observed in lipid and lipoprotein concentrations. A significant genotype-by-treatment interaction (p = 0.02) was found for the plasma HDL-C response to the intervention program. In fact, having the DD genotype and being treated with gemfibrozil had a synergical effect on HDL-C levels. The results of this study suggest that the ACE I/D polymorphism influences the effect of gemfibrozil on plasma HDL-C levels.

Administration, Oral↗
PubMed2002

Is the gender difference in LDL size explained by the metabolic complications of visceral obesity?

BACKGROUND: Several studies have reported a significant gender difference in low-density lipoprotein (LDL) size, with men being characterized by smaller, denser LDL particles than women, and it has been suggested that the contribution of the greater accumulation of visceral adipose tissue in men compared with women may be a factor potentially contributing to the gender difference in LDL heterogeneity. MATERIALS AND METHODS: We measured LDL particle size by 2-16% nondenaturing polyacrylamide gradient gel electrophoresis in 299 men and 231 women in whom visceral adipose tissue accumulation was measured by computed tomography. A fasting plasma lipoprotein-lipid profile was also obtained in all subjects. RESULTS: Overall, the men were characterized by a more deteriorated metabolic risk factor profile, which included higher plasma insulin and triglyceride levels, a greater visceral adipose tissue accumulation (P < 0.001) and smaller LDL particles (251.7 +/- 5.2 vs. 254.4 +/- 4.2 A, P < 0.0001). This gender difference in LDL peak particle diameter remained significant (252.4 +/- 4.3 vs. 253.5 +/- 4.3 A, P < 0.01) after adjustment for sex-specific differences in plasma triglyceride levels by covariance analysis. Significant negative correlations were noted between the LDL particle diameter and the triglyceride concentrations in both genders (r = -0.52 and r = -0.36, P < 0.0001 for the men and women, respectively), with no gender difference in this relationship being found. However, viscerally obese women (visceral adipose tissue levels > 100 cm2) with increased plasma triglyceride concentrations (> 2.0 mmol L-1) still had larger LDL particles than viscerally obese men with a similar elevation in their triglyceride levels (251.6 +/- 4.9 vs. 248.7 +/- 4.5 A, P < 0.01). CONCLUSIONS: Results of the present study suggest that the reduced LDL particle size observed in men compared with women cannot be entirely explained by their higher visceral adipose tissue accumulation and increased plasma triglyceride levels. Moreover, the gender difference in LDL size could be influenced, at least in part, by the severity of the hypertriglyceridaemic state.

Adipose Tissue↗
PubMed2002

Variability in the response of HDL cholesterol to exercise training in the HERITAGE Family Study.

In the HERITAGE Family Study, 675 sedentary, healthy, white and black men and women, aged 17 to 65 years, performed 20 weeks of supervised cycle ergometer exercise at the same relative intensity and weekly volume. As a group, subjects had normal mean baseline lipid levels for North Americans with the exception of below average high density lipoprotein cholesterol (HDL-C) levels. A significant mean increase in plasma HDL-C of 3.6 % was observed; however, there was marked variability in responsiveness to training, ranging from a mean 9.3 % decrease in Quartile 1 of HDL-C response to a mean 18 % increase in Quartile 4 (P < 0.0001 by ANOVA). Parallel changes in HDL(2)-C and HDL(3)-C, apolipoprotein A-I levels, and lipoprotein lipase activity were noted across quartiles. The change in HDL-C across quartiles was inversely related to baseline HDL-C (p < 0.0001) and to changes with training in plasma triglycerides (p = 0.0007). No significant differences in HDL-C response were observed across quartiles by sex, race, age, or increase in VO(2)max with training; however, weak positive associations were observed with age-adjusted education level and with reduction in abdominal fat and increase in VO(2)max at the ventilatory threshold following training. Multivariate regression analysis including baseline variables and training responses only accounted for 15.5 % of the variability in the HDL-C response to training. Thus, marked variability was found in the HDL-C response to the same endurance exercise training stimulus with only a modest amount of the response predictable by identified nongenetic factors.

Adaptation, Physiological↗
PubMed2002

Fully automated radioligand binding filtration assay for membrane-bound receptors.

Here we describe a fully automated, hands-free radioligand filtration binding assay for dopamine D3 receptors. Three separate instruments were linked in tandem to perform the following operations: The Genmate and Genesis were linked to perform liquid handling, incubation, and the scheduling operations, while an automated harvester was used to perform rapid filtration. To minimize carryover of compounds, disposable tips were used for diluting and dispensing the compounds. A custom-designed tip holder was used to handle loading and pipetting by the Genmate 96-well pipettor. The assay for 84 compounds with six concentrations that spans six logs can be completed within 4 h. The reproducibility of the individual data point (cv < 10% between duplicates) and Ki (cv < 20%) is superior to that determined by manual procedures. Ki values of various dopamine ligands determined by the hands-free procedure are similar to published values. This technology reduces hands-on time (at least 70%), minimizes exposure to radioligands (up to 95%), and improves the reproducibility of results. The technology is applicablefor high-throughput screening and rapid determination of structure-activity relationship of compounds for many other membrane-bound receptors.

Animals↗
PubMed2001

Age and duration of follow-up as modulators of the risk for ischemic heart disease associated with high plasma C-reactive protein levels in men.

BACKGROUND: Plasma C-reactive protein (CRP) levels recently have been identified as an emerging risk factor for ischemic heart disease (IHD). However, whether plasma CRP levels predict an increased risk for future IHD beyond traditional risk factors has yet to be evaluated in a large prospective, population-based study. METHODS: The association between elevated plasma CRP levels and the risk for future IHD was investigated in the prospective, population-based cohort of 2037 IHD-free middle-aged men from the Quebec Cardiovascular Study. During a 5-year follow-up, 105 first IHD events were recorded. Baseline plasma CRP levels were measured using a highly sensitive assay. RESULTS: High plasma CRP concentrations (equal to or above vs below the median level of 1.77 mg/L) were associated with a significant 1.8-fold increase in IHD risk (95% confidence interval [CI], 1.2-2.7). This association remained significant after adjustment for lipid risk factors but not when the simultaneous contribution of nonlipid traditional risk factors was taken into account. Multivariate analyses indicated that CRP level predicted short-term risk for IHD (events that occurred < or =2 years after the baseline evaluation), but not long-term risk (>2 years). Moreover, high plasma CRP levels predicted an increased risk for IHD, independent of any other confounder, in younger (< or =55 years) but not in older (>55 years) individuals. CONCLUSION: Plasma CRP levels may provide independent information on IHD risk only in younger middle-aged men and in the case of IHD events that may occur relatively soon after the baseline evaluation.

Adult↗
PubMed2001

The human MIP-1beta chemokine is encoded by two paralogous genes, ACT-2 and LAG-1.

Human macrophage inflammatory protein-1 beta (MIP-1beta) is an Mr 8,000 acidic protein that is upregulated upon stimulation in monocytes, T cells, and other lymphocytes. This protein belongs to the CC chemokine subfamily and directs the migration of specific subsets of leukocytes. The first molecular clone was isolated in 1988, and ever since there has been confusion regarding the exact number of genes encoding this and closely related proteins. PCR primers were designed from two genomic GenBank entries to conduct single-strand conformational polymorphism analysis, sequence analysis, and PCR-RFLP, and we conclude that previously isolated clones referred to as MIP-1beta are derived from two genes, originally called ACT-2 and LAG-1. The two proteins share a common length and are identical at 89 of 92 amino acids. The first two amino acid differences, V12M and L20P, occur in the signal peptide, while the third, G70S, is in the mature protein. Within the transcribed region, the genes differ at 25 of 662 nucleotides. A survey of the NCBI expressed sequence tag database reveals that both genes are expressed in a variety of tissues, and five clones representing LAG-1 transcripts are alternatively spliced, with the 115-bp exon 2 omitted. Database searches for putative orthologues in other species revealed that the rabbit protein is about 80% similar to the two human proteins, while those of rat and mouse are 70-75% similar. Comparative sequence analysis of the human and animal proteins indicates substantially higher rates of protein evolution in the two rodents compared to human and rabbit.

Alternative Splicing↗
PubMed2001

Genetic variation at the lipoprotein lipase locus and plasma lipoprotein and insulin levels in the Québec Family Study.

The associations between the S447X, BamHI, HindIII and PvuII DNA variants of the lipoprotein lipase (LPL) gene and indicators of body fat, fat distribution and plasma lipids and insulin were studied in the Québec Family Study cohort. Strong linkage disequilibrium among all the markers was observed. For the S447X polymorphism, plasma very low density lipoprotein (VLDL)-cholesterol (chol) (P<0.001), total triglyceride (TG) (P=0.033) and VLDL-TG (P<0.001) levels were lower and high density lipoprotein (HDL)-chol level higher (P<0.001) in the subjects homozygous or heterozygous for X447 (X447+, n=160) compared to the homozygotes for the S447 allele (X447-, n=576). The BamHI, PvuII and HindIII polymorphisms were not associated with the plasma lipid values when all X447 allele carriers were removed. In addition, the HindIII polymorphism as well as the HindIII and S447X markers combination influenced the insulin area under the curve during an oral glucose tolerance test. We conclude that DNA sequence variation in the LPL gene contributes significantly to the variability in the levels of VLDL-chol, total- and VLDL-TG as well as HDL-chol. The effects of the other polymorphisms considered here are most likely mediated by their linkage disequilibrium with the S447X mutation. In addition, genetic variation at the LPL locus may, by an unknown mechanism, influence insulin metabolism but not body fat variability.

Adult↗
PubMed2001

Race differences in the response of postheparin plasma lipoprotein lipase and hepatic lipase activities to endurance exercise training in men: results from the HERITAGE Family Study.

Endurance exercise training is known to produce favorable changes in the metabolic profile including reduced plasma triglyceride (TG) and increased high-density lipoprotein (HDL) cholesterol concentrations. These metabolic improvements are likely to contribute to the reduced coronary heart disease (CHD) risk often observed in physically active individuals. However, the physiological mechanisms responsible for such improvements in TG and HDL cholesterol concentrations with endurance exercise are not fully understood. The effect of a 20-week endurance exercise training program on plasma lipoproteins as well as on post-heparin plasma lipoprotein lipase (PH-LPL) and hepatic lipase (PH-HL) activities were therefore examined in a sample of 200 White and 69 Black men who were part of the HERITAGE Family Study. As expected, there were decreases in adiposity and in abdominal fat accumulation following training in both White and Black men. We also found that exercise training was associated with decreases in plasma cholesterol, TG and apolipoprotein B levels, as well as with an increase in HDL cholesterol concentrations in White men. In contrast, Black men showed an increase only in HDL(2) cholesterol over the 20-week period. Higher PH-LPL and lower PH-HL activities were noted in both ethnic groups at follow-up. Whereas in White men improvement of the lipoprotein-lipid profile was related to increased PH-LPL activity, no association between PH-LPL (or PH-HL) and lipoprotein-lipid variables was observed in Black men. Results of the present study suggest that in Whites, the increase in PH-LPL activity in response to endurance exercise training is associated with a better lipoprotein-lipid profile, therefore reducing CHD risk. However, the generally better metabolic profile of Black individuals may minimize further improvement of lipoprotein-lipid concentrations by exercise training.

Adipose Tissue↗
PubMed2001

Stability of indicators of the metabolic syndrome from childhood and adolescence to young adulthood: the Québec Family Study.

The stability of indicators of the metabolic syndrome from childhood and adolescence to young adulthood was examined. The sample included 76 males and 71 females measured between the ages of 8 and 18 years and again as young adults (12 year follow-up). Indicators included the sum of three trunk skinfolds (SF3), mean blood pressure (MBP), and fasting blood glucose (GLY), high-density lipoprotein cholesterol (HDL-C), ratio of total cholesterol to HDL-C (CHOL/HDL), and triglycerides (TG). The indicators were subjected to principal components analysis to obtain a composite risk factor index (RFI). Partial interage correlations, controlling for initial age and length of follow-up, were 0.70 and 0.50 for SF3, 0.40 and 0.54 for MBP, 0.58 and 0.56 for HDL-C, 0.51 and 0.57 for CHOL/HDL, 0.37 and 0.20 (NS) for TG, 0.30 and 0.14 (NS) for GLY, and 0.51 and 0.46 for the RFI, in males and females, respectively. The results indicate that indicators of the metabolic syndrome are moderately stable from childhood and adolescence into young adulthood.

Adolescent↗