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Biomedical subjects

H Allain

Publications and source records attributed to H Allain.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

[Modification of aminergic neurotransmitters and neurobehavioral correlates in acute cerebral ischemia in the rat].

Aminergic neurotransmitters and their main metabolites concentrations are measured in four areas (posterior cortex, striatum, hippocampus, hypothalamus) of the rat brain, 24 hours after an acute ischemic injury (created by the occlusion of the four cephalic vessels). Simultaneously, spontaneous motility and neurological status are evaluated. The main results are the increase of 5 HIAA in striatum, hippocampus and cortex, associated with an increase of HVA in striatum. Motility as well as neurological scores are significantly decreased in ischemic animals when compared with controls. The conclusion is that this model of cerebral ischemia is may be useful for pharmacological assessment of drugs liable to antagonize cerebrovascular disorders.

Animals↗
PubMedDate not supplied

[Anti-cerebral edema properties of PEG 300 in triethyltin poisoning].

The polyethylene glycols (PEG) frequently used as solvents of non hydrosoluble molecules present toxic and pharmacodynamic properties. The effect of PEG 300 (10 ml/kg) on the modifications of the central nervous system (CNS) previously induced by a subchronic intoxication with triethyltin salt (TEE) (2 mg/kg p.o. for 5 days) has been studied in rat. The following parameters are recorded: measure of brain edema, concentration of the aminergic neurotransmitters in four different brain areas, neurological status, behaviour, mortality. The PEG 300 antagonizes or reduces some of the effects of the TEE: edema, behavioral disturbances, mortality. On the opposite, no change in the amines and their metabolites induced modifications is observed. This selective antagonism towards some of the components of TEE brain toxicity brings more information on pharmacological properties of this solvent and opens a discussion on the role of neurotransmitters on brain edema.

Animals↗
PubMedDate not supplied

[Comparative effects of seven beta adrenolytic agents on blood pressure after injection into the posterior hypothalamus of rats. The frequency heart and the plasma renin activity (author's transl)].

The author's studied the central action of seven beta-blocking agents: alprenolol, atenolol, bupranolol, oxprenolol, pindolol, practolol, propranolol. The drugs were stereotactically injected into the posterior hypothalamus of non anaesthesized rats. Three dosages were used. Blood pressure, heart rate and plasma renin activity (PRA) were recorded. 2. The seven beta-blocking drugs used decreased heart frequency for at least one dosages PRA always decreased but blood pressure was lowered only after administration of alprenolol, oxprenolol, pindolol. 3. The discussion deals with: --the specificity of the target, --the involvement of the central beta receptors into the PRA regulation, --the correlations between the cardiovascular responses and the pharmacological properties of the different molecules; the hypothetic role of the intrinsic activity is postulated --the dissociation between heart rate and blood pressure responses, suggesting the existence of two different receptors for the specific control of those two parameters.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

[Proton nuclear magnetic resonance in the pharmacologic study of cerebral edema].

Wistar male rats have been orally administered 2 mg X kg-1j-1 of triethyltin (TET) chloride for 5 consecutive days. The result was a cerebral edema which constituted a reproducible and useful experimental model for pharmacological screening of drugs used in ageing. Water content modifications and clinical behaviour for 11 days from the beginning of experiment have been linked to T1 and T2 proton relaxation times measured by nuclear magnetic resonance (1H-NMR). The observation of 3 central nervous system structures, which differ in white matter content, has lead to the conclusion that NMR is a more sensitive technique to follow up the edema evolution than the water content measurement alone; it has also allowed to discriminate intra from extra-cellular edema (osmotic and TET edema), and has proved the action of two drugs which are used in aging process treatment on the TET edema (dihydroergotoxine 2 X 10 mg X kg-1j-1 and (--) eburnamonine 2 X 50 mg X kg-1j-1). In the future the mastery of this technology will be used to study other nuclei (Na, K, P) which will bring more physiopathological informations and to pharmacological investigations of the brain by NMR tomography or focalised NMR.

Animals↗
PubMedDate not supplied

[Viewpoint on the methodology of drug trials affecting cognition of elderly patients].

Clinical trials for cognitive disorders in the elderly require specific methodological guidelines. They must take into account the psychosocial dimension of the patient and his family and must be based on serious neurobiologic knowledge. In degenerative dementias the progress of research concern genetics, molecular intercellular recognition and astrocytic cells. Biology of cognition like hippocampal long term potentiation provides good pharmacologic basis for trials. In normal brain aging several ways must be developed: aminergic systems, free radicals, excitotoxic amino-acid, nerves growth factors. Clinical trials bring informations for pharmacology and epidemiology. Cholinergic neurons are the main pharmacologic target but there are many other ones: GABA-ergic system, Tau protein, amyloid. A rigourous selection of patients allows to precise the nosology of illness responsible of cognitive disorders and to point-out early clinical signs that represent a more sensitive target. Diagnostic criteria are useful in Alzheimer's disease, memory impairment, vascular dementias and other dementias. Evaluation of stage and evolution of dementia, comorbidity, limits of age and caregiver are practical problems. The effects of drugs used to treat cognitive functions are subtle so it is necessary to detect them to choose the best tests in function of each trial. Laboratory investigations can be used to evaluate the response to drug administration. Ethical point of view is represented by the fact that old people with cognitive impairment must not be away from therapeutic progress. In this field we must consider carefully the consequences of cognitive impairment on patient judgment and consent to clinical trial. Legal problems are regulated by supranational rules and French directives of Huriet law.

Aged↗
PubMedDate not supplied

[Calcium antagonists and the central nervous system].

The calcium antagonists (CA) which are at our disposal are a pharmacological class potentially active on the calcium homeostasis at the central nervous system level. Instead of reviewing the whole possibility of therapeutical potential targets, the authors review the 3 main possible and up-to-date impacts of these compounds: cerebral vasoactivity, neurotransmission, cell death. The actual lack of good clinical trials in those fields is stressed as well as the consequent necessity to stimulate the undertaking of such trials in humans in order to avoid to limit the use of CA in the only cardio-vascular spectrum.

Animals↗
PubMedDate not supplied

[The elderly healthy volunteer: a necessity].

Phase I and II clinical studies performed in healthy elderly volunteers appear as a necessity in the design of any drug development. This is particularly true for drugs which will be indicated in age-related disorders. The essential aim is to obtain a maximum of results on kinetics, dosage and tolerance in this target population. Difficulties and specificities of these studies will be developed. This issue will contribute to improve the quality of Phase III studies and appears as a money-saving strategy.

Age Factors↗
PubMedDate not supplied

[A single-day survey in pharmacies on the consumption of analgesics and antipyretics].

A one day long survey of antalgics and antipyretics consumption was carried out in 6 pharmacies of a middle-size city. It first shows the majority of medical prescription (62.2%) over self medication (29.4%) and over pharmaceutic advice (8.4%) at the drug delivery. Women are the main consumers, especially in the youngest ones (20-40 years old). Paracetamol is the most used drug; in this indication, the search for the less expensive drug seems usual. Drug abuse cannot be demonstrated in this survey; the consumption of this category of drugs appears as important although for a short duration; and most of the time for pain considered as moderate and trivial. The possibility to carry out such surveys and possibly clinical trials in private pharmacies appears as an opportunity.

Adolescent↗
PubMedDate not supplied

[Zopiclone. Data of experimental pharmacology and clinical use].

Zopiclone is the first of the cyclopyrrolones, a new class of psychotropic agents which is chemically different from the benzodiazepines (BZD). From an experimental point of view it has qualitatively the pharmacological profile of the tranquilizer-hyponotics, and activity quantitatively differs from hypnotic BZD by its lower myorelaxant. The electroencephalographic studies also demonstrated that its power spectrum is characteristic of a product having a tranquilizing hypnotic potential. The cyclopyrrolones interact with GABA ergic neurotransmission, and have a high affinity for GABA receptor complex. They act on sites close to BZD sites, but physically different. The sleep polygraphic studies have shown that zopiclone has a specific profile. It respects the sleep architecture, specially the delta sleep which is even increased, in some studies. Its residual effects are absent or minimal, and its acceptability is good in the usual conditions of hypnotic prescription.

Animals↗