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M Beaudry

Publications and source records attributed to M Beaudry.

At least 19 recordsLinked to original sources
PubMed2000

Relations between the stage of cell maturation and lactate transporter activities in rat neonatal muscle cells in culture.

Lactate transport was investigated in newborn rat muscle cells in culture. The aim was to study the lactate transport function at two stages of cell differentiation in culture: (i) during the proliferative phase characterized by myoblasts and myotubes (MyB/MyT2) obtained after 2-3 seedings, (ii) when myotubes (MyT1) grow old in culture after 8-9 seedings. In both developmental stages MyB/MyT2, lactate was carried following a saturable and sigmoidal velocity curve: the Hill and the Scatchard plot analyses confirmed an allosteric or multisite mechanism of lactate transport with two classes of carriers: one of low and one of high affinity i.e., 8.6 and 0.95 mm, respectively, which are associated with high and low transport capacities (V(m)) i.e., 9.1 and 0.67 nm/min/mg, respectively. With MyT1, the velocity curve of lactate transport presented a hyperbolic profile, and the Hill plot analysis gave a Hill number near one suggesting that for cell aging in culture the decrease in cooperativity shows that lactate transport essentially occurs through the low affinity transport system. Inhibitor effects also contributed to evidence for at least two systems of transport. Results obtained from primary cells give evidence for the early activity of lactate transport system at the Myb/MyT2 stage and its evolution during cell aging in culture (MyT1). Sarcolemmal lactate transport in primary cultures of myocytes is accomplished by multiple carriers, neither of which are MCT1 or MCT2 as confirmed by immunoblots.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1999

Food insecurity: consequences for the household and broader social implications.

A conceptual framework showing the household and social implications of food insecurity was elicited from a qualitative and quantitative study of 98 households from a heterogeneous low income population of Quebec city and rural surroundings; the study was designed to increase understanding of the experience of food insecurity in order to contribute to its prevention. According to the respondents' description, the experience of food insecurity is characterized by two categories of manifestations, i.e., the core characteristics of the phenomenon and a related set of actions and reactions by the household. This second category of manifestations is considered here as a first level of consequences of food insecurity. These consequences at the household level often interact with the larger environment to which the household belongs. On a chronic basis, the resulting interactions have certain implications that are tentatively labeled "social implications" in this paper. Their examination suggests that important aspects of human development depend on food security. It also raises questions concerning the nature of socially acceptable practices of food acquisition and food management, and how such acceptability can be assessed. Guidelines to that effect are proposed. Findings underline the relevance and urgency of working toward the realization of the right to food.

Family↗
PubMed1998

Lactate transport in L6 skeletal muscle cells and vesicles: allosteric or multisite mechanism and functional membrane marker of differentiation.

Membrane lactate transport was studied in skeletal muscle cells and membrane vesicles from the L6 line in relation to in vitro myogenesis. In myoblasts, lactate was transported by simple diffusion and insensitive to classical inhibitors: a positive correlation between onset of creatine kinase activity and lactate transport in differentiated myotubes was observed and could be considered to be a functional marker of cell differentiation. In myotubes, complete analysis of the velocity curves (direct coordinates, Eadie-Scatchard plots, Hill plots) gave parameters showing that lactate was carried by an allosteric or multisite system. This was confirmed by using sarcolemmal vesicles and specific inhibitors. In whole cells, alpha-cyano-4-hydroxycinnamic acid (CIN) and parachloromercuribenzylsulphonic acid (pCMBS) inhibited the maximal velocity without modifying the global cooperativity of the system. The weak effect of 4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (DIDS), which has a low affinity constant (Ki = 22.5 microM), implicated the monocarboxylate system rather than the anionic exchanger as a carrier system in muscle cells. CIN and DIDS exhibited one type of interaction with lactate carriers, and the curvilinear shape of the lactate Hill plot with or without inhibitors suggested that inhibitors were active at the same family of interaction sites and had a common range of affinities. The apparent competitive inhibition of pyruvate (Ki = 3.2 mM) did not modify the transport pathway of lactate in L6 myotubes. In conclusion, kinetic analysis of lactate transport in the presence or absence of inhibitors gave evidence for a multisite lactate carrier activity in myotubes composed of two systems at least, related to two or three isoforms of lactate carriers.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1996

Lipids and stroke: a paradox resolved.

BACKGROUND: Although dyslipidemia is a well established risk factor for coronary artery disease, its relationship to ischemic cerebrovascular disease has remained unclear, perhaps because of the heterogeneous nature of strokes. METHODS: In a case-control study, we measured the serum concentrations of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, serum triglycerides, and lipoprotein(a) levels and determined the apolipoprotein E phenotype and serum ferritin level in 90 consecutive systematically investigated patients with stroke or transient ischemic attack of atherothrombotic origin. Ninety age-, sex-, and community-matched subjects served as controls. RESULTS: Plasma total cholesterol (5.99 vs 5.45 mmol/L [232 vs 211 mg/dL], P=.003), low-density lipoprotein cholesterol (3.96 vs 3.45 mmol/L [153 vs 133 mg/dL], P=.004), and serum triglyceride (2.09 vs 1.82 mmol/L [8] vs 70 mg/dL], P=.03) levels were significantly higher among the patients with atherothrombotic strokes and transient ischemic attacks than among the control subjects. The inverse was true for high-density lipoprotein cholesterol (1.07 vs 1.18 mmol/L [41 vs 46 mg/dL], P=.02) levels. No significant differences were found in lipoprotein(a) levels or in the distribution of apolipoprotein E phenotypes or allele frequency. Serum ferritin levels did not differ significantly between patients and control subjects. CONCLUSIONS: Elevated low-density lipoprotein cholesterol and triglyceride levels are significant independent risk factors in patients with proven atherothrombotic cerebrovascular disease manifesting as stroke or transient ischemic attack. The level of stored serum iron, as reflected by serum ferritin levels, does not correlate with the presence of atherothrombotic cerebrovascular or coronary disease.

Aged↗
PubMed1996

Alzheimer's disease: preliminary study of spatial distribution at birth place.

Alzheimer's disease (AD) is a neurodegenerative disorder which is characterized by a progressive loss of memory and the alteration of cognitive functions. At least three chromosomal segments have been associated with early-onset AD in genetic linkage studies. These results argue for a certain degree of heterogeneity in the genetic origin of some forms of AD, although environmental risk factors cannot be ruled out in late-onset AD. In this preliminary study, we analyzed the geographical distribution of the birth places of a sample of 235 AD cases born in a defined region of Quebec (Canada), between 1895 and 1935. We wished to test the hypothesis that risk factors acting at, or around birth place and time play a role in the etiology of AD. The field of study was divided into rural and urban areas. A reference population of live births was used to compute a measure of odds ratio (OR). The OR results showed a statistically significant excess of AD cases in the rural area as compared to the reference population. When stratified for sex, the OR results showed a global excess of female AD cases in both the rural and the urban areas. For men, only the urban area presented a statistically significant deficit. We also analyzed the structures of the genealogical kinships of the rural and urban sub-groups. Although AD cases from the rural sub-group were more closely related to each other than those from the urban one, removal of the kin pairs from the OR analysis seemed to have little effect on the rural/urban distribution of cases. Therefore, the OR results would not appear to be due primarily to a difference in the kinship structures of the two sub-groups. This could mean that some risk factors for AD afflict women more strongly than men, the effect being different depending on the urban or rural origin. However, potential biases such as a higher rate of report for women, differential migration between birth places or a differential mortality ratio between sexes could produce spurious results in the direction of what we have observed in this preliminary study.

Aged↗
PubMed1996

Season of birth and Alzheimer's disease: a population-based study in Saguenay-Lac-St-Jean/Québec (IMAGE Project).

The birth distribution of 399 cases of Alzheimer's disease (AD) identified in the region of Saguenay-Lac-St-Jean (Québec) was compared with that of: (a) the population currently living in the area; and (b) the population born during the same period in the same area. AD cases have been recruited since 1986 by the IMAGE Project. Cases and controls were grouped according to the month of birth and according to the day of birth using density estimation. Analyses showed a significant deficit of births in the month of May. We believe these preliminary results deserve further attention and we suggest two possible explanations that could lead to a deficit of AD births at specific periods during the year.

Aged↗
PubMed1996

Research utilization: once-a-day temperatures for afebrile patients.

CNSs AND OTHER Master's-prepared nurses are usually expected to lead research utilization (RU) efforts in organizations, but they often feel unprepared to do so. In this article, the need for clinical RU is discussed and ideas for implementation, using an adaptation of the Conduct and Utilization of Research in Nursing model, are described. The RU process is applied to research about once-a-day temperatures in afebrile patients. To assist nurses who are implementing research-based practice, we list studies that were used for the practice change, summarize the research base on the topic, and offer an example of clinical use of practice guidelines.

Body Temperature↗
PubMed1996

Genotypic and phenotypic characterization of Escherichia coli isolates from dogs manifesting attaching and effacing lesions.

Thirteen Escherichia coli isolates from dogs manifesting attaching and effacing lesions were characterized genetically with respect to the presence of the following virulence determinants associated with human enteropathogenic E. coli (EPEC): eaeA, encoding the outer membrane protein intimin; eaeB, which is necessary for inducing signal transduction; bfpA, encoding the bundle-forming pilus; and the EAF (stands for EPEC adherence factor) plasmid. These isolates were also analyzed phenotypically with respect to adherence to mammalian cells in vivo and in vitro. Nine of these 13 isolates were found to be eaeA positive by PCR: four of these nine were eaeB positive. The 5' end, but not the 3' end, of the eaeA gene was amplified by PCR when primers derived from the eaeA gene of EPEC were used. Six and eight of these 13 isolates were found to be bfpA positive and EAF positive, respectively. The bfpA gene and EAF locus were found on high-molecular-weight plasmids, whereas the eaeA and eaeB genes were chromosomally located when present. Only one canine E. coli isolate, 4221, which was positive for eaeA, eaeB, bfpA, and EAF, adhered to HEp-2 cells in a localized manner and was positive in the fluorescence actin staining test. The nine eaeA-positive isolates adhered to the mucosal surface of piglet ileal explants and induced some microvillus effacement. However, when tested in experimentally inoculated gnotobiotic piglets, isolate 4221 did not induce attaching and effacing lesions at any level of the intestinal tract. Our results indicate that canine E. coli isolates associated with attaching and effacing lesions share some properties with human EPEC but form a heterogeneous group.

Animals↗
PubMed1995

Relation between infant feeding and infections during the first six months of life.

We assessed the effect of the method of feeding on respiratory and gastrointestinal illnesses during the first 6 months of life among 776 infants born in New Brunswick, Canada. During a 1-year period, these infants were drawn from the offspring of a population of primiparous women in the province who, after at least 36 weeks of pregnancy, gave birth to one normal infant weighing 2500 gm or more. Data were collected by means of a self-administered standardized questionnaire mailed to every mother a week before her infant reached 6 months of age. The crude incidence density ratio (IDR) revealed a protective effect of breast-feeding on respiratory illnesses (IDR = 0.66; 95% confidence interval (CI), 0.52 to 0.83), on gastrointestinal illnesses (IDR = 0.53; 95% CI, 0.27 to 1.04) and on all illnesses (IDR = 0.67; 95% CI, 0.54 to 0.82). The protective effect of breast-feeding on respiratory illnesses persisted even after adjustment for age of the infant, socioeconomic class, maternal age, and cigarette consumption (adjusted IDR = 0.78; 95% CI, 0.61 to 1.00). Moreover, if we distinguished ear infection from other respiratory illnesses, we observed a separate protective effect for these two types of events. The results of this retrospective cohort study suggest a protective effect of breast-feeding in our population during the first 6 months of life.

Bottle Feeding↗
PubMed1994

Virulence properties and attaching-effacing activity of Escherichia coli O45 from swine postweaning diarrhea.

Escherichia coli O45 isolates associated with swine postweaning diarrhea in Québec were characterized with respect to virulence determinants genetically and investigated for their attaching and effacing (A/E) activities by experimental inoculation of gnotobiotic piglets and by the HEp-2 cell adherence assay. All of 32 isolates tested were negative for enterotoxigenic and verotoxigenic E. coli virulence determinants, heat-labile enterotoxin (LT), heat-stable enterotoxins (STap, STb), verotoxins (VT1, VT2), and F4 (K88), F5 (K99), F6 (987P), and F41, except one STb-positive and two F4-positive isolates. A total of 25 isolates hybridized with an EaeA probe, and 11 hybridized with an enteropathogenic E. coli adherence factor (EAF) probe. None of 32 isolates hybridized with a bundle-forming pilus (BFP) probe. The EAF, EaeA, and BFP factors have been associated with human enteropathogenic E. coli strains. A total of 10 of 12 eaeA-positive porcine O45 isolates induced A/E lesions characterized by intimate adherence of bacteria to the intestinal epithelial cell membrane with effacement of the microvilli, similar to those of human attaching-effacing E. coli. However, A/E lesions were not observed in the piglets inoculated with any one of three eaeA-negative O45 isolates. All E. coli O45 isolates were non-adherent to HEp-2 cells. Thus, we have demonstrated the production of typical A/E lesions by nonenterotoxigenic E. coli O45 isolates from swine postweaning diarrhea. The results indicate the significance of the eaeA gene in A/E activities of these isolates and suggest that EAF and BFP are not involved in O45 E. coli infection of weaning piglets.

Adhesins, Bacterial↗
PubMed1993

Protection of islets of Langerhans from antibodies by microencapsulation with alginate-poly-L-lysine membranes.

Microencapsulation of islets has been proposed to prevent their immune destruction following transplantation. An indirect immunofluorescence technique has been developed and used to study the permeability of the alginate-poly-L-lysine microcapsules to antibodies. Wistar rat islets were incubated with the R2D6 monoclonal mouse IgM antibody against rat islets, microencapsulated, and incubated with fluorescein-labeled goat IgG antibodies against mouse IgG and IgM. For the negative controls, the first antibody was omitted or both antibodies were omitted. The positive controls included islets incubated with both antibodies before they were encapsulated. Our study demonstrated that the alginate-poly-L-lysine membranes are not permeable to IgG when poly-L-lysine of molecular weights ranging from 21,000 to 390,000 are used. This simple immunofluorescence technique demonstrated the nonpermeability of the microcapsules to IgG, and could be useful for the initial evaluation of new types of membranes.

Alginates↗
PubMed1993

From the Canadian Dietetic Association. Concept of dietetic practice and framework for undergraduate education for the 21st century.

Rapid change and marked diversity are expected to characterize the 21st century. If dietitians are to serve as change facilitators in this environment they will have to demonstrate greater flexibility and creativity, practise critical analysis and problem solving and employ creative thinking. Although provision of quality nutrition care will remain the unique contribution of dietitians, practitioners in the future will require a greater understanding of the impact of social, economic and political systems on food availability and food consumption and, in turn, health and well-being. Critical to the future practice of dietetics will be a greater understanding of research methodology, computer technology, quality improvement processes and risk management, principles governing learning and behaviour, personnel management and organizational behaviour, family and group dynamics, interpersonal communication and their application to dietetic practice. The Canadian Dietetic Association recently adopted a framework for the development of baccalaureate programs in dietetics designed to enable the dietetic practitioner to continue to make a unique contribution in the 21st century. The framework allows individual institutions the freedom and flexibility to plan programs that are compatible with their philosophy and organizational structure. In addition, it is predicted on the principle that a career in dietetics entails a lifetime commitment to education, of which the baccalaureate program is only the beginning.

Canada↗
PubMed1992

Lactate transport during differentiation of skeletal muscle cells: evidence for a specific carrier in L6 myotubes.

Cellular uptake of lactate involves a carrier in numerous types of mammalian cells. In cultured rat L6 myoblasts, lactate diffuses freely. We show that during myogenesis a carrier appears at the myotube stage. The degree of cellular differentiation was determined by microscopic observation and by measurement of a marker of biochemical differentiation: the increase in specific activity of creatine kinases.

Animals↗
PubMed1991

Lactate transport in skeletal muscle cells: uptake in L6 myoblasts.

During exercise, lactate is produced by degradation of glucose-6-phosphate during glycolysis in the contracting muscles. This lactate is metabolized during and after exercise in the muscle itself and also in the liver and other muscles, which can use it as an energy metabolite or can resynthetize glycogen. Lactate is transported in the blood, and the rate of muscular utilization may be limited by two factors: the rate of metabolic utilization by the muscle cell; and the rate of transport across the membrane regulating lactate transfer from the blood to the cell. We have studied lactate uptake in L6 muscle cells by incorporation of 14C-lactate. The uptake rates were linear for 20 seconds with 5 mM lactate and 10 seconds with 20 mM. The uptake during 10 seconds for physiological lactate concentrations (1-20 mM) gave a straight line passing through the origin. Lactate uptake was not altered by specific inhibitors of lactate transport (2.5 mM alpha cyano-4-hydroxycinnamic acid. 5 microM 4,4'-diisothiocyanostilbene-2,2'disulphonic acid) or by the stereospecific D-lactate inhibitor. The results suggest that L-lactate uptake in L6 cells occurs by passive diffusion.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1991

A conceptual framework for dietetics.

The model for the practice of dietetics recently adopted by the CDA board of directors clarifies how the different facets of dietetics are interrelated and part of a common definition of dietetics. It is our hope that this discussion will help us to move beyond the question of identity we often feel in our profession and will stimulate debate and the development and testing of alternate models; this should further clarify the essence of dietetic practice and enable us to continue to improve our unique and common contribution towards the provision of quality nutritional care to the population.

Canada↗
PubMed1991

[The marriage therapist is a Trojan horse: reflections inspired by the results of research on interventions with couples].

Communication training and positive exchange training are the two methods for improving marital relations that research has established as being the most effective. However, even after conducting therapy involving both partners based on these methods, too few couples (35%) succeed in reaching the same level of satisfaction as couples who are already satisfied with their relationship. The efforts that have been undertaken to increase this rate have focused mainly on developing new therapeutic techniques that include cognitive, emotional and systemic approaches. However, the results of experimental studies to date do not prove the superiority of these new approaches. Given this situation, it is time to pay more attention to particular characteristics of the therapeutic relation in marital therapy and to the means of obtaining the collaboration of the two spouses. As is the opinion of certain authors, the most difficult clinical task does not consist of finding what the clients must do to solve their problems, but rather to determine how to motivate them and help them achieve their goal. An analysis of this task, based on clinical observations and results of recent research in this area, has allowed the authors to present a number of hypotheses about ways to reinforce the therapeutic alliance and eventually reduce the failure rate of marital therapy.

Humans↗