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Biomedical subjects

G Leclerc

Publications and source records attributed to G Leclerc.

At least 91 records · Page 5Linked to original sources
PubMed1980

Synthesis and structure-activity relationships among alpha-adrenergic receptor agonists of the phenylethanolamine type.

Nineteen arylethanolamine derivatives related to norepinephrine were prepared and tested for alpha-adrenergic stimulant activity. In one series the analogues possess a p-hydroxy function, while the meta position is substituted by methyl, ethyl, isopropyl, chlohexyl, fluoro, chloro, iodo, carboxy, carbomethoxy, and methylsulfamido groups. The other series is meta hydroxylated with the para position substituted by the same groups. The influence of these groups upon the alpha-adrenergic activity is discussed, and the compounds are compared to octopamine, normetanephrine, norepinephrine, and norphenylephrine. It has been found that the introduction of an isopropyl, cyclohexyl, and fluoro group in the meta position of octopamine improves its affinity by three, five, and six times, respectively, whereas when these groups are introduced in the para position of norphenylephrine their effects are always detrimental. The most active compound, alpha-(aminomethyl)(4-fluoro-3-hydroxyphenyl)methanol (44), has about one-hundredth the affinity and the same intrinsic activity as norepinephrine.

Adrenergic alpha-Agonists↗
PubMed1980

Studies on some para-substituted clonidine derivatives that exhibit an alpha-adrenoceptor stimulant activity.

1 alpha-Adrenoceptor stimulant activity was determined for noradrenaline (NA), clonidine and a series of para-substituted derivatives of clonidine on rat aortic strips, a rat brain synaptosome preparation, and anaesthetized pithed rats. The effects on the blood pressure of intraventricular (i.c.v.) injections of para-aminoclonidine were also determined in anaesthetized rats. 2 Para-substituted derivatives of clonidine (amino-, diethylamino-, ethylamino-, acetamido-, bromoacetamido-, N-chloroethyl-N-methyl-amino and N-beta-chloroethyl-N-methylaminomethyl-) retain alpha-adrenoceptor stimulant activity. 3 pD2 values determined on rat aortic strips were 11.2, 7.67 and 9.05 respectively for para-aminoclonidine, clonidine and noradrenaline. The Ki values of these agents, determined on a rat brain synaptosomal preparation with a radioreceptor assay using [3H]-clonidine as ligand, were 1.3, 8.0 and 23 nM respectively for para-aminoclonidine, clonidine and NA. When given by i.c.v. injection in rats, para-aminoclonidine lowered the blood pressure. 4 N-beta-chloroethyl-N-methylaminomethylclonidine is an alkylating agent with an unusual agonist activity. It elicits contractions of the rat aorta that persist despite repeated washing. 5 alpha-Adrenoceptor affinities are discussed in relation to their structural features.

Adrenergic alpha-Agonists↗
PubMed1978

[Pharmacological study of para-aminoclonidine, an alpha sympathomimetic].

Para-aminoclonidine is a more potent alpha-adrenergic agent than clonidine; in vitro on Rat aorta it is 150 times more active than NE, in vivo on pithed Rat it is still twice as active. The hypotensive action of paraaminoclondine is only manifested when given intraventricularly. In the conscious Rat, it has a diuretic action when given per os. Following IV injection in the anaesthetized Dog, the para-aminoclonidine induces an essentially hydric diuresis which is independet of its hypertensive action.

Adrenergic alpha-Agonists↗
PubMed1978

Study of fluorescent treponemal antibody test on cerebrospinal fluid using monospecific anti-immunoglobulin conjugates IgG, IgM, and IgA.

The fluorescent treponemal antibody test for cerebrospinal fluid (FTA-CSF) using monospecific conjugates anti-IgG, IgM, and IgA was used to determine the presence of anti-treponemal antibodies in the spinal fluid of 335 patients with primary, secondary, and latent syphilis and symptomatic and asymptomatic neurosyphilis and of patients with certain neurological disorders. Of these, 230 (68·65%) patients had non-reactive results to this test. Of the remaining 105 patients, 78, 63, and 10 had reactive results with anti-IgG, IgM, and IgA conjugates respectively. Of the 129 cases of known syphilis, 11 were diagnosed as primary, 32 as secondary, and 50 as latent, and 36 patients had neurosyphilis. None of the specimens from the patients with primary syphilis gave reactive results to the test. Specimens from 21 (65·62%) of the 32 patients with secondary syphilis, 30 (60%) of the 50 patients with latent syphilis, and all (97·22%), except one, of the 36 patients with neurosyphilis gave reactive results to one at least of the IgG, IgM, or IgA FTA-CSF tests. Among the specimens from patients with secondary syphilis twice as many gave reactive results with anti-IgG conjugate than with anti-IgM conjugate. However, with specimens from patients with latent syphilis and neurosyphilis this ratio was diminished to 1·5:1. The Kolmer complement-fixation test, although superior in sensitivity and specificity to the Venereal Disease Research Laboratory (VDRL) test, in patients with secondary and latent syphilis and neurosyphilis, was greatly inferior to the FTA-CSF test. Data indicate that anti-treponemal antibodies can be detected in the spinal fluid even in patients with no neurological symptoms in cases of secondary syphilis and that the FTA-CSF test can be a valuable tool in the early detection of an immunological response to treponemal infection in the spinal fluid.

Cerebrospinal Fluid↗
PubMed1977

Synthesis and beta-adrenergic blocking activity of a novel class of aromatic oxime ethers.

A new series of beta-adrenergic blocking amines containing an oximino-propanolic chain linked to an aromatic nucleus was synthesized. Most of the derivatives are characterized by beta2-selectivity. The structure-activity relationship are discussed. One of the compounds, selected for further studies, was more active on the trachea than on the atria of guinea pig, 155 times in vitro and 26 times in vivo. In comparison, butoxamine's beta2-selectivity is 13 in vitro and only 2 in vivo. With a series of 30 acetophenone oxime derivatives, no quantitative structure-activity relationships could be detected.

Adrenergic beta-Antagonists↗
PubMed1977

A potent new beta2-adrenoceptor blocking agent.

1 (t-Butyl-amino-3-ol-2-propyl) oximino-9 fluorene is a new beta2-adrenoceptor blocking agent with a pA2 of 9.23+/-0.25 on isolated trachea. 2 It provokes hypertension in normotensive rats and does not prevent arterial hypertension in SHR rats, although it does prevent the renin secretion normally induced by isoprenaline infusion.

Adrenergic beta-Antagonists↗
PubMed1976

Clonidine and related analogues. Quantitative correlations.

Twenty-two structural derivatives of clonidine [2-(2,6-dichlorophenylimino)imidazolidine] have been synthesized and their main physicochemical parameters (log P, deltaRM, pKa) determined. Quantitative correlations between the peripheral alpha-mimetic action (pithed rats) and physicochemical parameters pointed out the critical role of the steric effect in the ortho positions. On the other hand, attempted quantitative correlations between physicochemical parameters and central hypotensive activity were unsuccessful. These results are discussed in the light of the postulated mechanism of action of clonidine.

Adrenergic alpha-Agonists↗
PubMedDate not supplied

The impact of a support group programme for care-givers on the institutionalisation of demented patients.

Support group programmes have been proposed to alleviate the care-givers' burden and postpone institutionalisation of demented patients. Experimental studies on these programmes failed to detect any impact on care-givers' burden, but none have examined the effect on institutionalisation. The objective of this paper is to assess the impact of a support group programme for care-givers on the institutionalisation of demented patients. Forty-five care-givers of community-dwelling demented patients were allocated randomly to the study group (n = 24) and the control group (n = 21). Subjects in the study group attended a structured programme of 8 weekly sessions of 3 h each. Subjects assigned to the control group were referred to the informal monthly meetings of the Alzheimer's Society. Using survival analysis, the median length of time until institutionalisation was 30 months from the time of the entry into the study. At 24 months, the probability of being institutionalised was 0.33 in the study group and 0.45 in the control group. This difference was not statistically significant (log-rank test: chi2 = 1.02; P = 0.31). These results emphasize the lack of scientific evidence about efficacy of such programmes and the need for a large multi-centre study on this topic.

Journal Article↗
PubMedDate not supplied

The influence of family and social relationships on the consumption of psychotropic drugs by the elderly.

Psychotropic drugs are the second most commonly used medication by Quebec's elderly. The objective of this study is to test a theoretical model of psychotropic drug use in the elderly. The principal hypothesis is that the quality of relationships the elderly person has with others, particularly with his or her children, has a direct influence on his or her psychological well-being, which, in turn, directly affects the consumption of psychotropic agents. A survey was conducted on a sample of 500 elderly people, aged 65-84 years, living at home. Of the respondents, 31.8% used psychotropic drugs during the 3-month period preceding the interview. Path analysis led to the elaboration of a modified model for the consumption of psychotropic drugs by the elderly which indicates that the best predictors of consumption are both the psychological well-being and the state of health of the individual. The more the psychological well-being is elevated, the lower the consumption of psychotropic drugs is, whereas a poor health condition increases it. The quality of an individual's social relationships has a direct influence on his or her psychological well-being, whereas family relationships are of lesser importance. Our model accounts for 13% of the predictors of psychotropic consumption by the elderly. Further studies will consider the personality of the user, the doctor-patient relationship, the prescribing habits of physicians and the influence of advertising by pharmacological industry.

Journal Article↗
PubMedDate not supplied

Efficacy of a support group programme for care-givers of demented patients in the community: a randomized controlled trial.

Dementia induces morbidity not only in the patients but also in the families taking care of them. Many studies described the impact of care-giving on physical and psychological health. Support groups were designed to alleviate the burden of care-givers. The objective of this study was to measure the efficacy of a support group programme for care-givers of demented patients in the community. Forty-one primary care-givers were randomly assigned to a study (n=23) or a control group (n=18). Subjects of the study group attended a structured programme of eight 2-h sessions. These weekly sessions consisted of information on the disease, role-playing on management of behavior problems, discussion on emotional impact of care-giving, and learning of stress management techniques. Subjects of the control group were referred to informal monthly meetings of the Alzheimer's Society. Subjects of both groups were evaluated at the entry (T1), after 8 weeks (T2) and after 8 months (T3). The outcome variables were the Burden Interview, the Revised Memory and Behavior Problems Checklist, the Brief Symptoms Inventory, the Alzheimer's Disease Knowledge Test and a questionnaire on health care utilization. Compared with the control group, subjects of the study group yielded only a significant increase in knowledge about the disease (p<0.0001) but no significant difference on the other outcome variables. It is concluded that this type of support group programme seems to have only a minimal impact on morbidity and on the burden of care-givers. These results are similar with two other studies examining the same issue.

Clinical Trial↗
PubMedDate not supplied

[Synthesis, biological activity and encapsulation of new adrenergic beta-amino alcohols in phospholipid liposomes].

New beta-amino-alcohols were synthesized and showed beta-blocking biological activity. These potential drugs, as well as natrium salicylate, have been entrapped in phospholipid liposomes. Drug-containing liposomes were prepared from egg lecithin and DPPC (Dipalmitoylphosphatidylcholine) by the injection method. Turbidity measurements and dynamic light scattering were used to characterise the liposome and to study their stability during storage. The entrapment efficiency of the drugs in liposomes was correlated to the partition coefficient of the drugs.

Adrenergic beta-Antagonists↗