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Biomedical subjects

M F Poirier

Publications and source records attributed to M F Poirier.

At least 55 records · Page 3Linked to original sources
PubMed1995

[Initiating thymoregulator treatment].

It is currently agreed that starting a lithium therapy is justified, as soon as the evolution of recurrent affective disorder is evident, by: the occurrence of an acute depressive episode during the four years preceding the current acute episode, that is to say 2 obvious acute episodes within 5 years which is enough to make highly probable a new acute short or medium dated episode; an acute manic episode caused by the high level of recurrence in bipolar patients and the frequent severe congruencies of an acute manic episode. The prophylactic efficacy of the lithium salts has been proved by several placebo-controlled studies: the result of these trials states that with placebo the recurrence level varies between 38% and 93%, whereas with lithium it is between 0% and 44%. The controlled trials in the sixties and seventies have made evident that about 1/3 of bipolar patients do not respond to lithium, the results varying according to the selection tests, the duration of the observation, the definition of the failure. We'll address three up to date questions. 1) Whereas the level of the lithium therapy is rather well established (0.6 to 1 mEq/l) and is of a great preventive efficacy with patients that are maintained in the high zone of the therapy scale, the present question is to know if it is necessary to split up the dose of lithium or to administer the daily dose in a single dose in the evening.(ABSTRACT TRUNCATED AT 250 WORDS)

Antidepressive Agents↗
PubMed1993

[40 years of neuroleptic drugs].

Since the Delay, Deniker and Harl's initial report, the story of neuroleptics comprises three distinct periods. Firstly the discovery of several drugs and of their clinical effects occurred and was followed only a posteriori by definition. In 1963, Carlsson supported a hyper-dopaminergic theory of psychoses. A second period began with many biochemical hypotheses concerning schizophrenia (serotoninergic, noradrenergic, glutamatergic hypothesis...). These hypothesis should be considered as "not proven" but their presence means that schizophrenia is most probably a multi-neurotransmitter-system disease and that several critical issues remain to be clarified concerning the dopamine hypothesis of schizophrenia. During these years (1960-1980) almost all "available compounds" have been marketed. In the eighties a third period seems to begin. The notions of refractory schizophrenia and of atypical neuroleptics have been described. An "atypical" neuroleptic is an effective antipsychotic drug without inducing concomitant extrapyramidal side effects. The concept of atypicity has become a new vista for research of new antipsychotic drugs. The notions of partial dopaminergic agonism, antagonism of D4 receptor, selective 5HT2 antagonism must be viewed as a source of future research and therapeutic improvement.

Antipsychotic Agents↗
PubMed1993

[Recovery from depression. Psychobiologic criteria of recovery].

Many biological studies of mood disorders attempted to identify markers linked with neurobiological effects of antidepressant treatments. One has to acknowledge that presently there are no useful markers of depression, as for instance markers of cancer. However, abnormalities have been noted in clinically heterogeneous subgroups of patients. Compared to the great number of investigations dealing with biological criteria in the diagnosis of depression, only a few studies addressed the issue of the course of biological parameters prior to, during and after treatments. But if these abnormalities are closely related to the depressive condition, it is important to establish whether they disappear when patients recover. Only longitudinal studies can answer these questions. Moreover, the few available studies concern the therapeutic response, rarely recovery. To declare that a patient recovered from depression means he recovered from the depressive episode, not from the illness itself. The sometimes discordant results reported by different groups on the course of biological parameters measured during depression may be partly due to differences in the exact time when one decides a patient recovered: early recovery when investigations take place between 3 weeks and 4 months after the beginning of the episode--a period of frequent relapse--and when persisting biological abnormalities will unmask the vulnerability of apparent clinical recovery. In some studies, only the investigations performed after 4 months of evolution demonstrated a normalization of initially disturbed biological indices, concomitantly with a genuine recovery, protecting against relapse. Thus, the biological normalization may be prognostically interesting, revealing that a period of remission has consolidated or not. Moreover, some biological abnormalities are said to be constitutional.(ABSTRACT TRUNCATED AT 250 WORDS)

Antidepressive Agents↗
PubMed1992

[Effect of psychotropic drugs on vigilance and motor performances].

This review paper deals with the impact of psychotropic drugs on vigilance, awakening and motricity. Antidepressants can be divided into 3 categories, depending on the subject's awakening: sedatives with a strong anticholinergic component, compounds devoid of positive or negative impact on cognition and stimulating antidepressants. The principal effect of lithium is to lengthen the reaction time. Taken acutely, neuroleptics produce alterations of fine motor gestures, but when taken chronically they spare the functioning of cognition. Benzodiazepines act on vigilance in various ways, depending on their half-life and on their plasma peak time after oral administration. The effect of anticonvulsants on cognition is more pronounced with phenytoin and barbiturates than with carbamazepine or valproate sodium. The problems of comparative analysis in this field and the trends in current studies are underlined.

Anti-Anxiety Agents↗
PubMed1992

Characterization of the 5-hydroxytryptamine receptor modulating the release of 5-[3H]hydroxytryptamine in slices of the human neocortex.

In the rat brain, the presynaptic 5-hydroxytryptamine (5-HT) autoreceptors located on 5-HT terminals correspond to the 5-HT1B subtype. The presence of a 5-HT receptor probably located on 5-HT nerve endings and modulating transmitter release in the human neocortex has been reported, but its detailed pharmacological characterization is not yet available. On the other hand, receptor binding and autoradiographic results indicate that the 5-HT1B receptor subtype is not present in the human brain. We, therefore, studied the modulation of the electrically evoked release of [3H]5-HT by various 5-HT receptor agonists and antagonists in preloaded slices of human neocortex obtained from 18 patients undergoing neurosurgery. The nonselective 5-HT1A/1B/1D receptor agonist 5-carboxamidotryptamine produced a potent inhibition (70% at 0.03 microM) of the electrically evoked release of [3H]5-HT which was blocked by 5-HT receptor antagonists with the following relative order of potency: methiothepin greater than metergoline = methysergide greater than propranolol. The selective 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin at 0.1 microM did not modify the electrically evoked release of [3H]5-HT. The 5-HT1A/1B receptor agonist RU 24969 was 10 times more potent at inhibiting [3H]5-HT overflow in the rat frontal cortex than in the human neocortex. The potent 5-HT1B receptor antagonist cyanopinodolol did not modify the 5-carboxamidotryptamine-induced inhibition of the electrically evoked release of [3H]5-HT in slices of the human neocortex, but produced by itself a small inhibition of [3H]5-HT overflow.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Natural autoantibodies in schizophrenia.

Autoantibodies reacting with cell constituents other than antinuclear antibodies have seldom been reported in the literature on schizophrenia. Serum of 41 DSM-III-R schizophrenic patients was examined for the presence of various autoantibodies and compared with that of healthy volunteers (n = 10) and hospitalized controls. Titers of IgG, IgA and IgM autoantibodies directed against actin, tubulin, myosin, DNA, thyroglobulin, elastin, albumin, DNA and trinitrophenyl groups were determined using enzyme immunoassay. IgG and IgA titers were significantly decreased in schizophrenic patients. These results contrast with those obtained with various other autoimmune and nonautoimmune diseases in which titers are either unchanged or increased. A significant increase of various autoantibody levels was observed in the paranoid subgroup of schizophrenics compared with the disorganized subgroup. These autoantibodies possess characteristics similar to those of natural autoantibodies, which seem to play several biological roles.

Adolescent↗
PubMed1991

[Topographical analysis of endogenous evoked potentials in depressed old people and in patients with Alzheimer's type dementia].

Latencies, amplitudes and localization of the maximum of the peaks of late onset evoked responses have been studied in 3 groups of elderly people: normal, depressed and demented (probable dementia of Alzheimer type DAT) at the early stage of the disease. Evoked responses with an auditory oddball paradigm have been recorded with 16 electrodes in 2 situations: counting the target sounds, and motor response with measurement of the reaction time. No difference in amplitude was observed between the 3 groups. Only a significant difference for P3 latency was observed between the DAT and the depressed groups and only in the counting situation. The maximum P3 response was most often found on the anterior areas in the DAT group and in the posterior areas in the normal and depressed groups. The topographic localization of the P3 peak could therefore be of some help in the characterize of subjects with probable DAT at the early stage of the disease.

Aged↗
PubMed1991

Comparison of acetorphan with clonidine for opiate withdrawal symptoms.

OBJECTIVE AND METHOD: The authors compared the effects of acetorphan, an enkephalinase inhibitor, with those of clonidine for the treatment of the opioid withdrawal syndrome. Nineteen patients addicted to heroin or synthetic opiates who were undergoing drug withdrawal and displayed a withdrawal syndrome according to DSM-III criteria were studied for 5 days in a hospital setting. In a double-blind trial, 10 subjects were given acetorphan intravenously and nine were given clonidine; objective signs and subjective symptoms of withdrawal were recorded. RESULTS: On several objective signs, the effect of acetorphan was more marked than that of clonidine, whereas the two drugs exhibited similar efficacy with respect to the subjective components of withdrawal. No side effect was noted in the subjects who received acetorphan. CONCLUSIONS: Enkephalinase inhibition may constitute a novel and safe therapeutic approach to the opioid withdrawal syndrome.

Adolescent↗
PubMed1991

The estimated density of D2 striatal receptors in schizophrenia. A study with positron emission tomography and 76Br-bromolisuride.

The striatal D2 receptors of 19 untreated schizophrenics and 14 normal control subjects were investigated with PET and 76Br-bromolisuride. The ratio of radioactivity in the striatum to that in the cerebellum was taken as an index of the striatal D2 receptor density. There was no significant difference between the control and the schizophrenic groups, nor any difference between subgroups of patients defined by clinical type or course of illness, and no relationship between the striatum:cerebellum activity ratio and SANS or SAPS ratings of symptoms. Unlike in the controls, this ratio was not correlated with age in schizophrenics. This study suggests that there is no quantitative abnormality of striatal D2 dopamine receptors in schizophrenia.

Adolescent↗
PubMed1991

[Biological risk factors in depression].

Various biological abnormalities have been reported in depressed patients. They concerned: Monoamines, assessed by measuring neurotransmitters precursors, catabolites, activity of synthesis and catabolism enzymes, uptake and release velocity. Membrane structure and physiology via receptors and transmembrane. Ionic changes. Neuroendocrine systems. Biological rhythms. Abnormalities are inconsistent and varied. No coherent theory of depression can account for these abnormalities: no biological measure can be considered as a specific marker. It is important to look for non specific factors of variation of these indices. Overall it is difficult to determine whether a reported biological abnormality can be considered as a cause or a consequence of the clinical feature. A vista for future research may be the availability of new investigation techniques as brain imaging and molecular genetics.

Biogenic Monoamines↗
PubMed1990

Diagnostic and therapeutic value of testing stimulation of thyroid-stimulating hormone by thyrotropin-releasing hormone in 100 depressed patients.

The thyrotropin-releasing hormone (TRH) test was performed in 100 depressed patients, including 73 patients with a major depressive episode (MDE) according to DSM-III. Thirty-one patients subsequently received an antidepressant with a predominant serotoninergic action (indalpine or citalopram), and 27 patients received a noradrenergic antidepressant (maprotiline). The diagnostic value of the TRH test was not conclusive for any of the subgroups of depressed patients: MDE, MDE with melancholia or MDE in bipolar patients. Similarly, the value of the TRH test in the choice of antidepressant treatment according to the monoaminergic action was not convincing. These results are discussed in the light of the data of the international literature.

Adult↗