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Biomedical subjects

M Dufour

Publications and source records attributed to M Dufour.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Alcohol and calories: a matter of balance.

Many epidemiological studies show that alcohol-derived calories added to food intake of men and women in amounts of 0-25% of total energy do not appreciably alter the average daily intake of other macronutrients (carbohydrate, fat, and protein). With such lack of evidence for caloric compensation, alcohol and its calories seem to make little contribution to metabolic energy, body weight, or body composition (as indicated by the body mass index, BMI). In fact, a major study by Colditz et al. (Am. J. Clin. Nutr. 54:49-55; 1991) reported a clear inverse relationship between alcohol intake and BMI for women! Research on alcohol metabolism has left unresolved some apparent contradictions regarding the effect of alcohol on caloric control, appetite and satiation, and body mass and composition. To resolve those apparent contradictions, the National Institute on Alcohol Abuse and Alcoholism cosponsored with the National Institute of Diabetes and Digestive and Kidney Diseases and the Beltsville Human Nutrition Research Center of the U.S. Department of Agriculture an all-day workshop titled "Alcohol and Calories: A Matter of Balance" on January 27, 1993. The workshop included sessions on calorimetry and body mass maintenance, alcohol metabolism, thermoregulation, and an overview of energy balance. This report provides summaries of the four discussion sessions at the workshop.

Alcohol Drinking↗
PubMedDate not supplied

A glucagon fragment is responsible for the inhibition of the liver Ca2+ pump by glucagon.

Glucagon specifically inhibits the Ca2+ pump in liver plasma membranes independently of adenylate cyclase activation. However, this inhibition is only observed at high concentrations of glucagon (Ki = 0.7 microM). Moreover, in the presence of bacitracin, an inhibitor of glucagon degradation, the Ca2+ pump is no longer sensitive to glucagon. These findings suggest that a fragment of glucagon might be the true effector of the liver Ca2+ pump. Pairs of basic amino acids are recognized as potential cleavage sites in post-translational processing of peptide hormones. The glucagon molecule includes a dibasic doublet (Arg 17-Arg 18). Therefore, we have examined the action of glucagon(19-29) on the liver Ca2+ pump. This peptide was obtained from glucagon by tryptic cleavage and separated by reverse-phase high-performance liquid chromatography. We found that glucagon(19-29), which is totally ineffective in activating adenylate cyclase, inhibited both the Ca2+-activated and Mg2+-dependent ATPase activity [Ca2+-Mg2+) ATPase) and Ca2+ transport in liver plasma membranes with an efficiency 1,000-fold higher than that of glucagon. Glucagon(1-21) was completely inactive; glucagon(18-29) and glucagon(22-29) acted only as partial agonists of glucagon(19-29). These results indicate that glucagon(19-29), obtained by proteolytic cleavage of glucagon, is likely to be the active peptide involved in the inhibition of the liver Ca2+ pump. We suggest that glucagon may be a precursor of at least one biologically active peptide.

Ca(2+) Mg(2+)-ATPase↗
PubMedDate not supplied

Sperm calcium levels and chlortetracycline fluorescence patterns are related to the in vivo fertility of cryopreserved bovine semen.

Cryopreserved bovine semen is less fertile than fresh semen for reasons that have not been fully elucidated. Cryopreservation is known to disrupt the sperm plasma membrane and it induces premature capacitation of a sperm subpopulation, which may be a result of the increased internal calcium levels after thawing. To test the hypothesis that sperm intracellular calcium level is correlated with in vivo fertility, we used the fluorescent calcium indicator, indo-1, and flow cytometry to assess intracellular calcium levels in frozen-thawed sperm from bulls of varying degrees of fertility. We also tested a second hypothesis that the physiological status of sperm, as assessed by the chlortetracycline (CTC) fluorescent assay, is correlated with fertility. As detected by indo-1 fluorescence, the intracellular calcium level is negatively correlated with bull fertility immediately after thawing (P = .0362; n = 3 ejaculates from each of 10 animals). Moreover, there was a significant difference between the 3 most and least fertile bulls over 4 hours of incubation (P < .05; n = 3 ejaculates per bull). Finally, there was a positive correlation between sperm displaying the CTC acrosome reaction pattern and fertility (P = .0014; n = 3 ejaculates from each of 10 bulls).

Acrosome Reaction↗
PubMedDate not supplied

[Hemopigmented villonodular synovitis].

Pigmented Villonodular Synovitis (PVNS) in an infrequent tumoral like disease and there are only a few MRI studies published. Concerning our series of five cases compared with the literature, the readers attention is drawn to the etiologies still under debate and to the respective contribution of the different imaging methods. MRI known for its high sensibility, but also for its low specificity in tumoral pathology, has turned out to be, in the case of PVNS, quite remarkable in both regards. The RMI aspect is quite well correlated to the histological structure of this synovial hyperplasia and to its evolution: highly vascular mass at the beginning and then low cellular density stroma, fibrous, with deposition of hemosiderin. In our five cases, as in almost all those previously reported in the literature, MR imaging shows heterogeneous areas of decreased signal intensity on T2 weighted sequences and on two of our cases after administration of gadolinium. Still the same MR aspects can be found in rheumatoid, hemophilic arthritis, as well as synovial chondromatosis, and therefore the clinical background and findings as well as plain films become essential. MR imaging should be the first examination to be undertaken after plain films, leading in most cases to a precise local preoperative assessment.

Female↗
PubMedDate not supplied

Drinking levels, knowledge, and associated characteristics, 1985 NHIS findings.

Several questions in the 1985 Health Promotion and Disease Prevention Questionnaire, which was part of the 1985 National Health Interview Survey, addressed respondents' consumption of alcohol. Sociodemographic characteristics, knowledge of health risks related to heavy drinking, health practices, and the prevalence of certain health conditions were examined in relation to drinking levels. Although cause-effect relationships should not be inferred from the associations, the findings suggest some provocative areas for prevention and research. Heavier drinkers were more commonly found among men than women. Level of drinking was associated positively with years of education and family income, but was inversely related to age. Compared with light drinkers, heavier drinkers were much more likely to drive after they had had too much to drink. While more than 90 percent of the population knew that heavier drinking increases the risk of 'liver cirrhosis, less than half knew about the increased risk of throat cancer and cancer of the mouth. Most respondents aged 18-44 years (80 percent or more) knew that heavy drinking increases the chance of adverse pregnancy outcomes, and more women than men (62 versus 49 percent) had heard of fetal alcohol syndrome (FAS). However, 70 percent or more of those who had heard of FAS described the syndrome as a newborn addicted to alcohol rather than a child born with certain birth defects. Heavier drinkers of both sexes were less likely than others to be nonsmokers, and moderate drinkers were more likely than others to exercise or play sports regularly. Moderate drinkers also tended to have lower lifetime prevalence rates than others for hypertension and heart trouble.

Adolescent↗
PubMedDate not supplied

Assessment of the potential for surveillance of alcohol-related casualties using National Hospital Discharge Survey data.

It is well known that alcohol abuse is significantly involved in the incidence of casualties (that is, accidents and injuries as they are defined for the purpose of coding diagnoses in the International Classification of Diseases). Thus, a study was conducted of the feasibility of using data from the National Hospital Discharge Survey (NHDS) for the surveillance of alcohol-related casualties. Trends were analyzed over 7 years (1979-85), and results were discussed from three aspects: number and rates for comorbidity of injuries and accidents with alcohol-related diagnoses, percent of alcohol involvement for injuries and accidents, and proportionate morbidity for alcohol-related and nonalcohol-related injuries and accidents. The incidence of comorbidity and percent of alcohol involvement were found to be relatively low for both accidents and injuries--underreporting being a likely cause. Comorbidity rates over the 7-year period showed no major trends in the rates for injuries that were associated with alcohol use, but the rates for accidents that were associated with alcohol use increased in all but one of the years. Proportionate morbidity as reflected in hospital discharge records with alcohol-related diagnoses showed only small differences by sex and age group (except the 14 to 25 years group) for either injuries or accidents. Only the 25- to 44-year-old group showed a time-trend increase, and that is only for the accident category. For these reasons, we have concluded that data from the NHDS are not currently adequate for use in the surveillance of alcohol-related injuries and accidents.

Accidents↗