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Biomedical subjects

D Dumas

Publications and source records attributed to D Dumas.

50 records · Page 3Linked to original sources
PubMed1982

Modulation by catecholamines and thyrotrophin of cyclic AMP response to beta-adrenergic stimulation by cultured porcine thyroid cells.

Thyroid cell cyclic AMP synthesis is stimulated by beta-adrenergic agonists. We have characterized this sensitivity on cultured porcine thyroid cells and have studied its modulation by chronic treatment with thyrotrophin. The synthesis of cyclic AMP in intact porcine thyroid cells in primary culture was stimulated by the beta-adrenergic agonist, isoproterenol. This stimulation was dose-dependent and was inhibited by the beta-adrenergic antagonists propranolol and alprenolol. The cell responsiveness (i.e. the response elicited by 5 microM-isoproterenol after 5-min stimulation) was increased when the cells were cultured in the absence of thyrotrophin. Thyrotrophin, when present in the culture medium at the onset of culturing, inhibited this increase. A concentration of 100 microunits. thyrotrophin/ml was sufficient to reduce the cyclic AMP response to 15% of its control value. Prostaglandin E2 or dibutyryl cyclic AMP did not mimic the effect of thyrotrophin. The low sensitivity of thyrotrophin-treated cells to beta-adrenergic agonists could be explained by a decreased number of beta-adrenergic receptors. [125I]Iodohydroxybenzyl pindolol specific binding was ten times greater in membrane preparations of control cells than in membranes derived from thyrotrophin-treated cells. The beta-adrenergic sensitivity of cultured thyroid cells was also decreased after long-term treatment by terbutaline. A time- and dose-dependent desensitization was observed.

Alprenolol↗
PubMedDate not supplied

A study of self-perception in hyperactive children.

PURPOSE: This research aimed to describe self-perception among hyperactive children in comparison with a general population of children of the same age. DESIGN: A descriptive study with 116 children (between 6 and 11 years of age) distributed as follows: 57 hyperactive (20 girls and 37 boys) and 59 control group (25 girls and 34 boys). The hyperactive children were being treated at the outpatient clinic of a child psychiatry hospital. The children in the control group were recruited from a Quebec City elementary school. METHODS: Children in both groups participated in an interview during which they answered the Self-Perception Profile for Children (r = 0.90) consisting of six well-defined subscales. DATA ANALYSIS: Univariate analyses were used to describe the sociodemographic characteristics of both hyperactive and control group children. Groups were compared using t and chi-square tests. Univariate statistics were used to describe the characteristics of self-perception for each group overall and for each of the dimensions. Multivariate analysis was used to compare self-perception in hyperactive and control group children. RESULTS: All dimensions of self-perception were lower among hyperactive children than among children in the control group, except athletic competence, which was higher. Multivariate analysis indicated that the dimensions of scholastic competence, social acceptance, and behavioral conduct were problem areas for hyperactive children. CLINICAL IMPLICATIONS: Nursing care interventions for children with attention deficit hyperactivity disorder (ADHD) should be developed which assist children in increasing self-perception. This is a first step in developing a comprehensive plan of care.

Attention Deficit Disorder with Hyperactivity↗
PubMedDate not supplied

[Use of standard for quantitation of adhesion of polynuclear neutrophils by flow cytometry].

Adherence receptors are essential for heterotypic (endothelial cell, platelet) polymorphonuclear neutrophil (PMN) interaction. Determination of their expression level give information about activation state and functionality of PMN. Use of flow cytometry associated with an immunolabeling standard, represented by beads coated by a determined amount of immunoglobulins (Qifikit, Dako), allows analysis of specific antibody binding capacity and gives information about antigen density. Using this methodology, the exploration of surface adherence receptors, L-selectin (CD62L) and b2-integrins (CD11a-c/CD18) from PMN unstimulated and incubated with pro-inflammatory stimuli, formyl-methionyl-leucyl-phenylalanine (fMLP) and tumor necrosis factor a (TNFa), allows, on the one hand, the establishment of basal expression values on resting PNN and on the other hand, the study of PNN reactivity. This method of quantification can be applied to clinical studies as adherence receptor deficiency syndromes or inflammatory, infectious and vascular diseases.

Adult↗
PubMedDate not supplied

[Self perception: the key stone of nursing interventions with hyperactive children].

Denise Dumas, a nurse at the Hôtel-Dieu du Sacré-Coeur de Jésus hospital, in Quebec City, and Louise Pelletier, an associate professor at the Ecole des sciences infirmières of Université Laval, are interested in promoting understanding of problems linked to hyperactivity in school-age children. They suggest appropriate nursing interventions for child psychiatry units in hospitals and outpatient clinics. The authors give a definition of attention-deficit hyperactivity disorder, specifying its prevalence, etiology and treatment, and describe the behaviour of the hyperactive child. They go on to look at the concept of self-perception and deal with its development and its importance in children's lives. Most importantly, the authors suggest nursing interventions suited to the needs of hyperactive children.

Attention Deficit Disorder with Hyperactivity↗
PubMedDate not supplied

Effect of glutaraldehyde on hemoglobin-dependent quenching of pyrene fluorescence. Application to oxygen diffusion in erythrocyte.

In the present study, we investigate the effect of glutaraldehyde incorporation on the erythrocyte deformability, membrane fluidity and process of molecular oxygen diffusion. The erythrocyte deformability variations were inversely related with the glutaraldehyde concentration incorporated. The membrane fluidity, as assessed by a method based on the kinetics of pyrene dodecanoic acid excimers formation, decreased as the glutaraldehyde concentration increased. So, we verified that glutaraldehyde incorporation was accompanied by membrane rigidification. In the presence of glutaraldehyde, decreased absorption of hemoglobin heme group (420 nm) and decreased hemoglobin-dependent quenching of pyrene butyric acid (PBA) fluorescence would result from hemoglobin polymerization. Using a technique of fluorescence intensity quenching by molecular oxygen (accessibility to oxygen), we showed that oxygen diffusion was decreased in the presence of glutaraldehyde. To conclude, membrane rigidification induced by glutaraldehyde incorporation would affect oxygen molecular process.

Butyrates↗