117 research outputs found
Étude de la sélection de l'habitat préférentiel du rat musqué (Ondatra zibethicus) dans des étangs aménagés au lac Saint-Pierre, Québec
Expression and activity of 20α-hydroxysteroid dehydrogenase (AKR1C1) in abdominal subcutaneous and omental adipose tissue in women
We have examined the expression and activity of 20a-hydroxysteroid dehydrogenase (20a-HSD)
in abdominal adipose tissue in women. This recently-characterized enzyme from the
aldoketoreductase 1C family (AKR1C1) is responsible for the conversion of progesterone into
20a-hydroxyprogesterone. Abdominal subcutaneous (SC) and omental (OM) adipose tissue
biopsies were obtained from a sample of 32 women aged 47.7+-5.9 years (BMI: 27.6+-5.0 kg/m2
)
undergoing abdominal hysterectomies. Body composition and body fat distribution
measurements were performed before the surgery by dual energy x-ray absorptiometry and
computed tomography respectively. The expression of 20a-HSD was determined by real-time
RT-PCR, and its activity was measured in whole tissue homogenates. Messenger RNA and
activity of the enzyme were detected in both the SC and OM fat depots, the two measures being
significantly higher in the SC compartment. Women characterized by a visceral adipose tissue
area greater than or equal to 100 cm2
had an increased 20a-HSD conversion rate in their omental
adipose tissue compared to women without visceral obesity (13.99+-2.07 vs. 7.92+-0.83 fmol/ug
protein/24h, p<0.05). Accordingly, a positive correlation was found between omental adipose
tissue 20a-HSD activity and computed tomography-measured visceral adipose tissue area
(r=0.36, p<0.05). Significant positive correlations were also found between omental 20a-HSD
activity and omental adipocyte diameter (r=0.49, p<0.05) and omental adipose tissue LPL
activity (r=0.36, p=0.06). In conclusion, 20a-HSD activity and mRNA were detected in SC and
OM adipose tissue in women, and omental 20a-hydroxylation of progesterone was highest in
women with visceral obesity. Further studies are required to establish whether local conversion of
progesterone may impact on the metabolism and function of adipocytes located within the
abdominal cavity
Modélisation de la structure temporelle et spatiale d'images infrarouges: Étude des modèles d'ajustement des PSD représentatifs des arrières-plans dans l'infrarouge.
Developpement d'un nouvel outil simple et adaptable pour l'evaluation de la vulnerabilite des eaux souterraines a la contamination par les pesticides.
Perfluoroalkyl acids in pregnant women from Nunavik (Quebec, Canada) : trends in exposure and associations with country foods consumption
Objectives
From 2004 to 2017, 279 pregnant Inuit women were recruited as part of biomonitoring projects in Nunavik. Our goal was to evaluate: (i) time-trends in plasma/serum PFAAs levels in pregnant Nunavimmiut women between 2004 and 2017; (ii) compare plasma/serum PFAAs levels in Nunavimmiut women in 2016–2017 to those measured in women of childbearing age in the Canadian Health Measure Survey (CHMS); and (iii) evaluate the associations of PFAAs levels with the consumption of country foods and pregnancy and maternal characteristics during pregnancy in the 97 participants recruited in 2016–2017.
Methods
Individual blood sample were collected for serum or plasma PFAAs (PFOS, PFOA, pentafluorobenzoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorobutanesulfonic acid (PFBS), perfluorohexane-1-sulfonic acid (PFHxS), PFNA, PFDA, PFUdA) analyses. Socio-demographic data, pregnancy and maternal characteristics and country foods consumption were documented using a questionnaire. Omega-3 and −6 polyunsaturated fatty acids (PUFA) were measured in red blood cell membranes and their ratio used as a biomarker of marine country foods consumption. Time-trends in PFAAs levels were evaluated using ANCOVA models adjusted for relevant co-variables. Serum/plasma levels of PFAAs in the 97 pregnant women aged 16 to 40 years old and recruited in 2016–2017 were compared to those measured in women aged 18 to 40 years old from the CHMS cycle 5 (2016–2017) using the geometric means (GM) and 95% confidence intervals (95% CI). Multivariate regression analyses were performed to examine associations between concentrations of PFAAs and country foods consumption data.
Results
Statistically-significant downward time trends were noted for concentrations of PFOS, PFOA and PFHxS in pregnant Nunavik women between 2004 and 2017. Conversely, between 2011 and 2016–2017, PFNA, PFDA and PFUdA maternal serum levels increased by 19, 13 and 21% respectively. Among participants in 2016–2017, mean concentrations for PFNA (GM: 2.4 μg/L), PFDA (0.53 μg/L) and PFUdA (0.61 μg/L) were higher than those measured in women aged 18–40 years old in the Cycle 5 (2016–2017) of the CHMS. PFOA (0.53 μg/L) and PFHxS (0.26 μg/L) were lower than in CHMS, whereas PFBA, PFHxA and PFBS were not detected in 2016–2017. Ratios of serum/plasma levels of PFNA/PFOA, PFNA/PFOS, PFNA/PFHxS and PFUdA/PFDA were significantly higher in the 97 pregnant women from Nunavik recruited in 2016–2017 compared to CHMS, highlighting their distinct exposure profile. In multivariate models, PFHxS, PFOS, PFNA, PFDA and PFUdA levels in 2016–2017 were strongly associated with the omega-3/omega-6 PUFA ratio, indicating a positive association between marine country foods consumption and higher exposure to PFAAs.
Conclusions
The exposure of pregnant women to long-chain PFAAs (PFNA, PFDA and PFUdA) increased from 2004 to 2017 in Nunavik. Associations noted between PFAAs levels and the omega-3/omega-6 ratio highlights the importance of implementing additional strict regulations on PFAAs and their precursors to protect the high nutritional quality and cultural importance of country foods in Nunavik
Perfluoroalkyl acid and bisphenol-A exposure via food sources in four First Nation communities in Quebec, Canada
Objective: To document perfluoroalkyl acids (PFAA) and bisphenol-A (BPA) exposure in four First Nation communities in northern Quebec compared with the Canadian Health Measures Survey (CHMS Cycle 5 2016–2017) and examine the associations between dietary consumption and chemical exposure. Design: We used cross-sectional data from the JES-YEH! project conducted in collaboration with four First Nation communities in 2015. A FFQ collected information on diet, and PFAA and BPA were measured in biological samples. We used generalised linear models to test the associations between food intake and chemical biomarkers. Setting: Northern Quebec. Participants: Youth aged 3–19 years (n 198). Results: Mean perfluorononanoic acid (PFNA) levels were significantly higher in JES-YEH! than CHMS, and BPA levels were higher among those aged 12–19 years compared with CHMS. Dairy products were associated with PFNA among Anishinabe and Innu participants (geometric mean ratio 95 % CI: 1·53 (95 % CI 1·03, 2·29) and 1·52 (95 % CI 1·05, 2·20), respectively). PFNA was also associated with ultra-processed foods (1·57 (95 % CI 1·07, 2·31)) among Anishinabe, and with wild fish and berries (1·44 (95 % CI 1·07, 1·94); 1·75 (95 % CI 1·30, 2·36)) among Innu. BPA was associated with cheese (1·72 (95 % CI 1·19, 2·50)) and milk (1·53 (95 % CI 1·02, 2·29)) among Anishinabe, and with desserts (1·71 (95 % CI 1·07, 2·74)), processed meats (1·55 (95 % CI 1·00, 2·38)), wild fish (1·64 (95 % CI 1·07, 2·49)) and wild berries (2·06 (95 % CI 1·37, 3·10)) among Innu. Conclusions: These results highlight the importance of better documenting food-processing and packaging methods, particularly for dairy products, and their contribution to endocrine disruptors exposures as well as to promote minimally processed and unpackaged foods to provide healthier food environments for youth in Indigenous communities and beyond
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