Biomedical subjects

A Villeneuve

Publications and source records attributed to A Villeneuve.

119 records · Page 7Linked to original sources

PubMedDate not supplied

Glucocorticoids increase preproendothelin-1 expression in rat aorta.

Glucocorticoids play an important role in circulatory homeostasis. They modulate peripheral resistance by their direct action on blood vessels. We have previously shown that glucocorticoids increase preproendothelin-1 gene transcription rate in vascular smooth muscle cells (Morin C et al. 1998, BBRC 244:583). Endothelin-1 is a potent vasoactive peptide involved in the maintenance of vascular tone as well as in pathophysiological states. In this report we show that glucocorticoids increase preproendothelin-1 expression in rat aorta. The rise in preproendothelin-1 steady state mRNA level is dose-dependent with a maximal 2.3-fold stimulation 8 hours following a 0.35 and a 2.5 mg/kg dexamethasone injection. A lower dose of dexamethasone (0.13 mg/kg) also increased preproendothelin-1 expression in rat aorta. Since endothelin-1 levels are regulated at the transcriptional step, the increase in mRNA is likely to be paralleled by increased protein synthesis and vasoconstrictor action. Moreover, systolic blood pressure was significantly elevated in rats who received the 0.35 and 2.5 mg/kg doses of dexamethasone. Together, our results strongly suggest that the increase in preproendothelin-1 expression by glucocorticoids contributes to the regulatory action of these corticosteroids on blood pressure in health and disease.

Animals↗

PubMedDate not supplied

[Side-effects of neuroleptics].

Due to their pharmacological activity on various receptors, particularly dopaminergic, cholinergic and adrenergic ones, neuroleptics induce various side effects, central as well as peripheric. These side effects are of various nature: psychic and cognitive, neurologic affecting mostly the extrapyramidal system, neuroendocrinian and metabolic, as well as neurovegetative. Toxic manifestations, hepatic, hematologic and others, have been associated with their use, as well as a malignant syndrome that can be lethal. They also have a potential teratogenic action. Their main side effects are therefore described and discussed as to their physiopathology and treatment. Nevertheless, in spite of their various side effects, neuroleptics represent a valuable and effective tool in the treatment of various psychotic disorders, namely schizophrenia. Their main pharmacological property is their ability to induce extrapyramidal side effects. In this respect, the prophylactic administration of an antiparkinsonian agent remains a controversial issue. Finally, the occurrence of tardive dyskinesia has given rise to civil litigation and ethical considerations should be borne in mind in their use.

Abnormalities, Drug-Induced↗

PubMedDate not supplied

[Ethics and clinical drug trials].

During the last decade, biomedical ethics has known a rapid development. Research in man, including clinical drug trials, must now take into account ethical and legal requirements. The concept of the inviolability of the human person constitutes the basic tenet of biomedical ethics. Four main principles ensue: the principles of autonomy, of nonmaleficience, of beneficience and of justice. Some rules derive from them, for instance veracity, confidentiality, fidelity and respect of intimacy with regard to the subject of an experiment. From a practical standpoint, the design of a clinical trial must be scientifically sound, otherwise it cannot be ethical. An informed consent must be obtained, in written form, from the subject in a clinical trial and he must be aware of his right to withdraw from it at any moment. Moreover, the clinical trial must be monitored throughout its duration with respect to ethics. An ethics of the methodology of clinical trials must therefore exist. Ethics in research should be a way of thinking and behaving, inherent to the research training. The researcher should be keenly conscious of the ethical requirements involved in his work, if he wishes to avoid eventual external interventions.

Clinical Trials as Topic↗

PubMedDate not supplied

[Tardive dyskinesia. After more than 2 decades].

The clinical aspects of tardive dyskinesia are describe, outlining the difficulties and the limits encountered by the clinician. The tools for its evaluation are reviewed, as well the epidemiology data and the current neuropathological hypothesis.

Animals↗

PubMedDate not supplied

[Lithium, pregnancy and breast feeding].

Due to its teratogenic potential and its passage in the maternal milk, the administration of lithium during pregnancy and post-partum, if breast-feeding is contemplated, raises specific issues. The kinetics of lithium during pregnancy is reviewed, as well as its influence on the foetus during this period and during breast-feeding. Its teratogenicity affects particularly the cardiovascular system, the Ebstein's anomaly being the most typical and frequent malformation. As a general rule, the administration of lithium should be avoided during pregnancy, at least during the first trimester. However, pregnancy and breast-feeding do not represent an absolute contraindication for the continuation of lithium therapy if it is deemed necessary, in spite of the risks that can be incurred and of which the patient should be informed.

Abnormalities, Drug-Induced↗

PubMedDate not supplied

[Neuropsychology of a psycho-organic syndrome caused by idiopathic hypoparathyroidism. Apropos of a case].

A case of organic psychosis secondary to an idiopathic hypoparathyroidism with intracranial calcifications affecting the basal ganglia and the cortico-medullary junction is described. The results of the skull X-ray, cerebral TACO and nuclear magnetic resonance imaging analyses are presented, as well as a battery of neuropsychological tests. In spite of the extensive calcifications found, deficits on the neuropsychological tests were minimal or non-existent; possible explanations of this discrepancy are discussed.

Adult↗

PubMedDate not supplied

Effect of clomipramine treatment on dog platelet alpha 2-adrenergic receptivity.

The effects of clomipramine treatment (5 mg/kg s.c. a day during 21 days) on dog platelet alpha 2-adrenoreceptivity were investigated. The radioligand binding studies on platelet membrane preparations showed that the antidepressant treatment promotes a decrease in the number of [3H]-yohimbine binding sites. The measurement of the inhibition of PGE1-induced cyclic AMP accumulation in the whole platelet indicated that the biological event immediately associated with alpha 2-adrenergic stimulation was not modified. The aggregatory response to ADP or ADP plus adrenaline was totally abolished in clomipramine-treated platelets. The diastolic pressor responses to noradrenaline or adrenaline injections (after propranolol and prazosin administration) in chloralose anaesthetized dogs were not affected by clomipramine treatment. This work shows that variations in the binding capacities of alpha 2-adrenergic sites are not always linked to modifications of related physiological events.

Adenosine Diphosphate↗

PubMedDate not supplied