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Biomedical subjects

C Villeneuve

Publications and source records attributed to C Villeneuve.

At least 19 recordsLinked to original sources
PubMed2006

Nicotine and smoker status moderate brain electric and mood activation induced by ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist.

As the increased smoking prevalence in schizophrenics may be interpreted as an adaptive response to an underlying biological defect, investigations into nicotine's actions within N-methyl-d-aspartate (NMDA) antagonist drug models of schizophrenia may improve our understanding of the role of glutamatergic neurotransmission in initiating and maintaining nicotine dependence in this disorder. In this double-blind, placebo-controlled, randomized study, the electroencephalographic (EEG) and subjective response to a sub-psychotomimetic intravenous dose of the NMDA antagonist ketamine was examined in 20 regular smokers and 20 non-smokers pretreated with placebo or nicotine gum. Although nicotine increased EEG arousal, ketamine produced electrocerebral signs of brain activation (decreased slow wave power) and sedation (decreased fast wave power and frequency), which were not affected by nicotine pretreatment and were evident only in non-smokers. Ketamine increased a number of self-report indices of subjective arousal, some of which were attenuated and potentiated by nicotine in smokers and non-smokers, respectively. These findings suggest that long-term (evidenced by smoker vs. non-smoker comparisons) and short-term (acute) nicotine exposure may alter NMDA receptor-mediated arousal and mood systems in a way that promotes nicotine dependence in smokers, and addresses neurobiological deficiencies in smokers with schizophrenia.

Adult↗
PubMed2003

Evaluation of the contribution of cyclooxygenase 1 and cyclooxygenase 2 to the production of PGE2 and PGF2 alpha in epithelial cells from bovine endometrium.

In ruminants, the production of prostaglandins by the endometrium is critical for recognition of pregnancy. In the absence of an embryonic signal, luteolytic pulses of PGF(2 alpha) are released by the uterus. In contrast, the presence of a viable conceptus reduces the production of PGF(2 alpha) relative to PGE(2) and prevents luteolysis through the release of trophoblastic interferon (IFN-tau). Initially, it was thought that epithelial and stromal endometrial cells were specialized in the production of a single type of prostaglandin. However, purified cell populations of both types of cell can produce PGF(2 alpha) and PGE(2); therefore, selective production of PGF(2 alpha) and PGE(2) must be regulated within each type of cell. Two distinct prostaglandin synthases, cyclooxygenase 1 and cyclooxygenase 2, are involved in prostaglandin production and each may catalyse the production of a different prostaglandin. This possibility was investigated in cultured epithelial cells from bovine endometrium. Cells were treated with oxytocin or arachidonic acid, and expression of cyclooxygenase 1 and cyclooxygenase 2 proteins was monitored over time and correlated with prostaglandin accumulation. Cells were also treated with increasing doses of inhibitors of cyclooxygenase 1 or cyclooxygenase 2 (non-steroidal anti-inflammatory drugs; NSAIDs) with or without arachidonic acid or oxytocin: flurbiprofen (0-50 micromol l(-1)) was used as a non-selective inhibitor; valeryl salicylate (0-500 micromol l(-1)) was used as a cyclooxygenase 1 inhibitor and NS-398 (0-1 micromol l(-1)) was used as a cyclooxygenase 2 inhibitor. After stimulation with arachidonic acid or oxytocin, prostaglandin production and expression of cyclooxygenase 2 protein were increased. All inhibitors were able to block basal and stimulated prostaglandin production. These results indicate that in endometrium most, if not all, prostaglandin production is probably processed through cyclooxygenase 2.

Animals↗
PubMed1998

Weight loss, dysphagia, and outcome in advanced dementia.

There has been much debate on the value and risks of long-term enteral feeding in patients with advanced dementia. A retrospective study was carried out on 47 patients with a primary diagnosis of dementia who died over a two-year period. All were inpatients in a nursing home or skilled nursing facility. Marked weight loss and dysphagia occurring in a specific pattern were found to be associated with death from pneumonia. These clinical features probably imply failure of basic homeostatic mechanisms. Patients showing this clinical pattern may be less likely to show benefits from long-term enteral feeding.

Aged↗
PubMed1996

Prevention concerning mental health: the adolescent's perspective.

OBJECTIVE: To examine several subjective components of adolescents' behaviour concerning mental illness prevention. METHOD: Adolescents' knowledge, their attitudes and subjective norms, as well as their thoughts about how they would concretely handle a psychological problem were measured. A self-administered questionnaire was completed by 438 male and female adolescents in grades 8 and 11. RESULTS: Gender and age differences were revealed: girls and older adolescents were more attuned to prevention. Further, the influence on young people of peers and parents was also apparent. CONCLUSION: Adolescents perceive prevention concerning mental health as important.

Adolescent↗
PubMed1995

Trapping gel electrophoresis of end-labeled DNA: an analytical model for mobility and diffusion.

As shown by Ulanovsky, Drouin and Gilbert (Nature 1990, 343, 190-192), the gel electrophoretic migration of DNA is severely reduced by steric trapping when streptavidin is attached to one end of the polyelectrolyte. We present a model that allows us to calculate both the mobility and the diffusion coefficient, hence the resolution factor of the resulting separation. We compare our results to those of Défontaines and Viovy (Electrophoresis 1993, 14, 8-17) and we show that the averages over the molecular conformations must be done carefully. We also show that trapping increases diffusion substantially and that this makes constant-field trapping electrophoresis incapable of increasing the number of bases read per sequencing run. Finally, we conclude that severe trapping may lead to highly anomalous transport behavior where one cannot define a velocity or a diffusion constant.

Bacterial Proteins↗
PubMed1995

Family therapy and some personality disorders in adolescence.

To prevent an endless debate between those supporting an intrinsic deficit versus an environmental deficit, the adolescent's problem has been seen here as both an individual problem and the metaphorical expression of a family problem. The intricacy of this two-faceted problem appears vividly with borderline and immature adolescents. Both the adolescent and family have, among other problems, difficulty separating. The approach described here focuses on that particular aspect; each therapeutic step is geared toward the adolescent's separation-individuation. Concerning the course of therapy, restructuring is perceived as the first therapeutic step and a prerequisite to work on such issues as delineating personal and family problems and improving communications. The approach is not, though, a panacea for the treatment of all personality disorders in adolescence and should not preempt the use of other approaches. As reported by Esman (1989) in regard to borderline adolescents, there is enough variation in the syndrome to allow the use of a variety of treatment approaches. Involving the family may not be feasible, and the adolescent sometimes must be removed from a detrimental family situation. The family of the immature or borderline adolescent is often seen as untreatable but what the therapist wants to accomplish and is ready to share often paves the way to effective intervention (Offer and Vanderstoep, 1974). The therapist must be ready to struggle with the family and with himself. The therapist has to be courageous, patient, and optimistic. The intervention is usually done on a middle-term basis with encouragement to the family to consult again if needed. The approach may thus appear obsolete at a time of a "quick-fix" culture. Family therapy can be a powerful tool with very disturbed, personality-disordered adolescents. The family approach must be flexible and based on a psychodynamic understanding of the problems. As so many of these cases fail to respond to the usual treatment and make therapists and institutions feel powerless, looking at the intervention from another angle can be refreshing. The experience can be rewarding for the adolescent, as she is becoming emancipated from the family, and for the parents, who facilitate the process. Working with these families is difficult but can also be rewarding for the clinician. Hours spent with them gives access to the subjective experiential reality that makes the substance of behavior and may allow the exploration of shadowy areas of the human condition. Family therapy becomes, then, a journey full of pain, uncertainties, and wonder for both the family and the clinician.

Acting Out↗
PubMed1990

[Family therapy: what is at stake in its evolution and its present application].

Applying family therapy remains marginal in several child psychiatric clinics in spite of a favorable theoretical context. The author describes certain difficulties that the family therapist faces and places them into the context of the development of family therapy. Secondly, he shows the basic mechanisms that support this kind of intervention and the constant that is revealed in present practice. At the same time, the author offers a practical model allowing both the use of a psychoanalytical perspective and the systemic approach.

Child↗
PubMed1988

Psychological aspects of ultrasound imaging during pregnancy.

The psychological impact of ultrasound examination on expectant parents is assessed through direct observation, interviews and the administration of a questionnaire to a large group of parents. The examination was a positive and reassuring experience for most parents. Among a wide array of variables that could account for the effects of the exam, the results were the most important. Women viewing their first ultrasound, specially primiparae were more moved. The results did not confirm that there is a traumatic effect when viewing precedes quickening. Contrary to previous reports, fathers were as emotionally involved as the mothers. The presence of the father seemed also to have a beneficial effect on the mother. One-half of parents wanted to know the sex of the fetus before birth. These findings are discussed, along with implications for problems arising from introduction of new technologies during pregnancy.

Adult↗
PubMed1983

[Evaluation of the family.].

The author discusses the clinical family evaluation. He discusses its advantages, and difficulties, as well its dangers, and presents a model of family evaluation. Although developped with a view to a child psychiatry practice, this model could also be applied to other mental health intervention contexts. The model in question is based on family interactions and considers the developmental level of the children. In the course of the evaluation, the family is invited to accomplish some activities in which the children can participate. Clinical cases serve to illustrate the model. The family evaluation should facilitate a better understanding of the child's psychological problems.

English Abstract↗
PubMed1978

Deanol, lithium and placebo in the treatment of tardive dyskinesia. A double-blind crossover study.

A double-blind crossover study on the effects of deanol and lithium carbonate was conducted on a sample of 29 chronic schizophrenic patients with tardive dyskinesia. In addition to his usual treatment with different neuroleptics, each patient received during an 8-week period either deanol, lithium carbonate or placebo. A 4-week wash-out period was inserted between each of the 8-week periods of experimental treatment of the tardive dyskinesia. The administration of either deanol, lithium carbonate or placebo added to the neuroleptic treatment did not produce a statistically significant improvement of tardive dyskinesia in our patient population as a whole. Favorable and unfavorable responses are discussed.

Adult↗