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Biomedical subjects

M Chagnon

Publications and source records attributed to M Chagnon.

At least 55 records · Page 3Linked to original sources
PubMed1994

DNA polymorphism in the uncoupling protein (UCP) gene and human body fat.

The objective of this study was to identify DNA sequence variation in the UCP gene and to investigate its relationship with some obesity phenotypes. Two studies were carried out: (1) association study in unrelated subjects, and (2) sib-pair linkage analysis study in brothers and sisters. The subjects were 261 individuals from the Québec Family Study (123 parents and 138 offsprings from 64 families). The following were measured: Body mass index, percent body fat (measured by hydrostatic weighing), and subcutaneous fat (estimated by the sum of 6 skinfolds) were measured in 1978-81 and again 12 years later. Resting metabolic rate (RMR) was measured only in 1989-93. Genetic analyses were performed using Southern blotting technique and a human UCP genomic probe. (1) A BcII restriction fragment length polymorphism was identified with two alleles of 8.3 and 4.5 kb in length, and respective frequencies of 0.28 and 0.72. (2) In unrelated adults from the parental generation, a cross-sectional analysis of the 1989-93 data showed no difference in body fat and RMR between the UCP genotypes. No significant difference for the absolute changes in body fat over the 12-year period among the UCP genotypes was observed. However, a higher frequency (P < 0.05) of the 8.3-kb allele was found in high gainers compared to low gainers (i.e., above and below the median value) for percent body fat over the 12-year period. (3) No evidence of linkage between any of the obesity phenotypes and the UCP BcII marker was found. For the first time, the presence of DNA polymorphism in the human UCP gene is reported. Although, no significant association and linkage were found between the UCP BcII gene marker and body fat in the cohort of the Quebec Family Study, a higher frequency of the 8.3-kb allele was found in individuals who gained more body fat over time.

Adipose Tissue↗
PubMed1992

Continuous improvement of nursing practice: experience in Québec.

Health care professionals must be accountable for the quality of their practice and self-regulating professional organizations have the responsibility to ensure that the public receives the best possible care to which it is entitled. Québec's legislation mandates professional corporations to supervise the practice of their members. The nursing profession comes under that legislation and, at l'Ordre des infirmières et infirmiers du Québec, a program of professional inspection has existed since 1976. The philosophy of this program is based on individual and collective responsibility of nurses towards the continuous improvement of their practice and the enhancement of the quality of care they provide. Standards and criteria of competence were elaborated with the participation of groups of nurses, validated by large samples of the population and distributed to all nurses. Evaluation tools were devised and have progressed over the years. The concepts of self-evaluation (Bandura, Am Psychol 33: 344, 1978; Bandura, Prentice Hall, 1986; Knox and MacKay, Nurs Papers/Perspect Nurs 4: 17, 1982) and of self-managed collective development (Payette, Rev québécoise Psychol 5: 104, 1984) have inspired the program, allowing nurses to identify their needs, set priorities and determine their plan of action. A study to evaluate the impact of the program is now in progress. This article will describe the conceptual framework, the method of evaluation, its application, the reactions of nurses as well as some of the results observed concerning the improvement of practice and of quality of care.

Canada↗
PubMed1991

A prospective study of sow mortality in breeding herds.

This investigation was conducted to study the incidence and the causes of sow mortality in breeding herds. Data were obtained from 24 swine breeding herds with an average inventory of 3755 sows and served gilts for the total sample. Producers were involved for 12 consecutive months and agreed to submit to the diagnostic laboratory every dead or moribund sow and served gilt. The average herd death rate was 3.3% +/- 0.5 (SEM), but varied considerably among herds, ranging from 0% to 9.2%. A total of 137 sows and mated gilts died during the year, and these females had produced an average of 4.2 litters +/- 0.2 (SEM). The number of deaths was significantly higher during the months of July, August and October. The peripartum period appeared to be when sows were most at risk, with 42% of all deaths occurring during this short period of the reproductive cycle. The three major causes of death were heart failure (31.4%), torsions and accidents of abdominal organs (15.3%) and cystitis-pyelonephritis (8.0%). Other causes included endometritis (6.6%), uterine prolapses (6.6%), pneumonia (3.6%), gastric ulcers (3.6%), downer sow syndrome (2.2%), miscellaneous (8.0%) and unknown (14.6%).

Animals↗
PubMed1990

The evaluation of postmortem ocular fluid analysis as a diagnostic aid in sows.

This study was undertaken to evaluate the diagnostic usefulness of postmortem ocular fluid analysis in estimating the antemortem status of various serochemical constituents. Chemical values of serum and aqueous and vitreous humors were compared following different procedures. A blood sample and the 2 eyes were collected from each of 100 sows at a nearby abattoir. The results obtained from immediate centrifugation of ocular fluids after sampling were compared with those samples in which centrifugation was delayed by 2 hours. Two different postmortem intervals were used for sampling ocular fluids, 2 and 24 hours. Concentrations of urea, calcium, phosphorus, potassium, sodium, and chloride were determined from serum and humors. Delayed centrifugation did not affect chemical values of ocular fluids nor the relationships between serum and humors. Phosphorus and potassium values increased significantly with the postmortem interval in both aqueous and vitreous humors. The relationships between chemical values of ocular fluids and serum were determined using simple linear regression. There was a poor correlation between ocular fluid and serum values for all electrolytes; a significant correlation was found only for urea concentrations in both humors.

Abattoirs↗
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 liposomes in the presentation of HIV envelope glycoprotein and the immune response in mice].

The role of antigen presentation in the induction of humoral as well as cell-mediated immune responses has been investigated by anchoring HIV-1 envelope glycoprotein (gp 160/120) into the phospholipidic bilayer of preformed liposomes to produce HIV-Immunosomes. HIV-Immunosomes induced high titres of HIV-specific antibodies when tested by ELISA, IFA and neutralization, whereas equal amounts of purified glycoprotein alone produced lower antibody response. Similarly, HIV-Immunosomes induced antigen-specific Interleukin-2 production and blastogenic response upon restimulation with the same antigen, in animals vaccinated with HIV-Immunosomes, whereas no secondary response was observed in animals vaccinated with equal amounts of purified gp 160/120. Taken together, these results underline the importance of antigen presentation in the establishment of an adequate immune status and show the potential of HIV-Immunosomes as vaccine against AIDS.

Animals↗
PubMed1987

Adenosine deaminase, adenylate kinase and acid phosphatase polymorphism in a French-Canadian population.

Adenosine deaminase (ADA), adenylate kinase (AK1), and acid phosphatase (ACP1) red blood cell enzymes were studied for allelic variation in a French-Canadian population from Quebec City, Canada. Allele frequencies in 887 unrelated individuals were for ACP1, ACP1*A: 0.305; ACP1*B: 0.635 and ACP1*C: 0.060, for ADA, ADA*1: 0.969, ADA*2: 0.031, and for AK1, AK1*1: 0.976, AK1*2: 0.024. The allele frequencies for each enzyme were identical to those previously reported in other Caucasian populations.

Acid Phosphatase↗
PubMed1986

Esterase D polymorphism in a French-Canadian population.

Red blood cell esterase D (ESD) polymorphism was studied in a French-Canadian population from Quebec city, Canada, by means of high voltage electrophoresis on agarose gel followed, in heterozygotes for ESD 1, by IEF to reveal the possible allele ESD*5. Frequencies of the ESD alleles in 904 unrelated individuals were ESD*1: 0.888, EDS*2: 0.095 and ESD*5: 0.017. The segregation pattern observed in 275 families confirmed a Mendelian inheritance of three autosomal alleles.

Alleles↗
PubMed1986

More on red blood cell genetic variation in Olympic athletes.

As a follow-up to De Garay et al. (1976) and Chagnon et al. (1984) studies, we are reporting on the genetic variation of four red blood cell enzymes in 49 athletes with isoelectric-focusing and electrophoresis techniques. The athletes were Caucasians participating in the 1976 Montreal Olympic Games. They were performing in 5 different sports and the sample included 18 women and 31 men. No uncommon allele was found and all known alleles were detected for each enzyme. Phenotypes and gene frequencies were computed and compared with appropriate populations of reference. No significant differences were observed for any of the enzymes. Moreover, no association was found between variation in these proteins and participation in rowing (N = 25) or track (N = 13) event.

Acid Phosphatase↗
PubMed1985

Role of cyclooxygenase products in the lung action of leukotrienes A4, B4, C4, D4 and E4.

Leukotrienes (LT) LTA4, LTB4, LTC4, LTD4 and LTE4 induced marked contractions of guinea pig lung parenchymal strips mounted in organ baths. These contractions were inhibited differentially (40-50% for LTA4, LTC4, LTD4 and LTE4, and 90% for LTB4) by indomethacin (20 micrograms.ml-1; 55.9 microM). Two novel inhibitors of thromboxane synthetase (OKY-1581 and OKY-046) reduced the myotropic activity of the lung strips and the release of prostaglandins and thromboxanes from the perfused guinea pig lungs stimulated by LTB4 and LTD4. The release of cyclooxygenase products prostaglandin F2 alpha, thromboxane B2 and 12-hydroxyheptadecatrienoic acid by guinea pig lungs following stimulation with LTB4 and LTD4 was also measured by gas chromatography-mass spectrometry. The role of prostaglandins and thromboxanes in the lung actions of leukotrienes was confirmed using a cascade superfusion system and classical organ baths. Although prostaglandins and thromboxanes contribute to the contractile effect of LTB4 on the guinea pig lung whereas they may play a lesser role in the action of the peptidoleukotrienes (approx. 40-50%), stimulation of their release by the peptidoleukotrienes is many times more effective than by LTB4.

Animals↗
PubMed1985

Metabolism of leukotrienes by adult and fetal human lungs.

The metabolism of leukotriene (LT) A4, B4, C4, D4, and E4 was studied using both bioassay and reversed phase high performance liquid chromatography (RP-HPLC) methods. The incubation of 20,000 g supernatants of homogenates of human adult lung with LTA4 and LTC4 for various periods of time produced substances of higher biologic activity than the controls (without incubation) when measured on strips of guinea pig lung parenchyma and ileum. RP-HPLC analyses of the incubation media revealed the formation of LTB4, LTC4, LTD4, and LTE4 from LTA4 and the formation of LTD4 and LTE4 from LTC4. LTD4 was converted to LTE4 whereas LTB4 and LTE4 were not catabolized to an appreciable extent during a 2-h incubation period. Supernatants (20,000 g) of human fetal lung homogenates also contain the enzymatic activities to transform LTC4 into LTD4 and LTE4; however, LTA4 was mainly converted to LTB4 and to products of the nonenzymatic hydrolysis of LTA4 such as the delta 6-trans-LTB4, delta 6 -trans-12-epi-LTB4 and the 5,6-dihyroxyeicosatetraenoic acids; much smaller quantities of the peptidoleukotrienes were formed than in adult lung homogenates.

Adult↗
PubMed1984

[General pharmacologic inventory of Rwandese medicinal plants].

A pharmacological screening was conducted on 101 methanolic extracts from 31 medicinal plants chosen among the more widely used plants in Rwandese traditional medicine. Twenty four extracts from 13 plants have shown spasmolytic properties, while 35 extracts from 15 plants contain spasmodic active principles. Ten extracts from 8 plants have shown considerable toxicity and 3 extracts from 2 plants have revealed curarizing properties.

Animals↗