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Biomedical subjects

R Brasseur

Publications and source records attributed to R Brasseur.

208 records · Page 12Linked to original sources
PubMedDate not supplied

Pharmacology of the hypoglycaemic sulphonylurea gliquidone. III. Conformational analysis.

The hypoglycaemic sulphonylurea gliquidone was found, by conformation analysis, to display a U-shaped configuration, with hydrophobic cycles placed at the extremity of each branch and a peptidic bond placed at the bottom of the U. This configuration is similar to that recently observed with the hypoglycaemic sulphonylureas glimepiride and glibenclamide and non-sulphonylurea hypoglycaemic agents of the meglitinide family, such as S3075, repaglinide, A-4166 and KAD-1229. The identification of a conformation common to these various hypoglycaemic drugs may provide an imprint of their binding site at the level of the B-cell sulphonylurea receptor.

Hypoglycemic Agents↗
PubMedDate not supplied

Translocation properties of novel cell penetrating transportan and penetratin analogues.

Novel analogues of the cell-penetrating peptides penetratin and transportan were synthesized. The distribution of the biotin-labeled peptides in Bowes melanoma cell line has been investigated by indirect fluorescence with fluorescein-streptavidin detection. The time course of uptake of (125)I-labeled transportan analogues has been characterized in the same cell line. Molecular modeling was used to analyze the penetration and the orientation of molecules in a simulated biological membrane. The results, both from molecular modeling and fluorescence studies, imply that penetratin and transportan do not enter the cells by related mechanisms and that they do not belong to the same family of translocating peptides.

Amino Acid Sequence↗
PubMedDate not supplied

Tilted peptides: a motif for membrane destabilization (hypothesis).

Cell life depends on the dynamics of molecular processes: molecule folding, organelle building and transformations involving membrane fusion, protein activation and degradation. To carry out these processes, the hydrophilic/hydrophobic interfaces of amphipathic systems such as membranes and native proteins must be disrupted. In the past decade, protein fragments acting in the disruption of interfaces have been evidenced: they are named the tilted or oblique peptides. Due to a peculiar distribution of hydrophobicity, they can disrupt hydrophobicity interfaces. Tilted peptides should be present in many proteins involved in various stages of cell life. This hypothesis overviews their discovery, describes how they are detected and discusses how they could be involved in dynamic biological processes.

Alzheimer Disease↗
PubMedDate not supplied

Contribution of the hydrophobicity gradient to the secondary structure and activity of fusogenic peptides.

Fusogenic peptides belong to a class of helical amphipathic peptides characterized by a hydrophobicity gradient along the long helical axis. According to the prevailing theory regarding the mechanism of action of fusogenic peptides, this hydrophobicity gradient causes the tilted insertion of the peptides in membranes, thus destabilizing the lipid core and, thereby, enhancing membrane fusion. To assess the role of the hydrophobicity gradient upon the fusogenic activity, two of these fusogenic peptides and several variants were synthesized. The LCAT-(57-70) peptide, which is part of the sequence of the lipolytic enzyme lecithin cholesterol acyltransferase, forms stable beta-sheets in lipids, while the apolipoprotein A-II (53-70) peptide remains predominantly helical in membranes. The variant peptides were designed through amino acid permutations, to be either parallel, perpendicular, or to retain an oblique orientation relative to the lipid-water interface. Peptide-induced vesicle fusion was monitored by lipid-mixing experiments, using fluorescent probes, the extent of peptide-lipid association, the conformation of lipid-associated peptides and their orientation in lipids, were studied by Fourier Transformed Infrared Spectroscopy. A comparison of the properties of the wild-type and variant peptides shows that the hydrophobicity gradient, which determines the orientation of helical peptides in lipids and their fusogenic activity, further influences the secondary structure and lipid binding capacity of these peptides.

Amino Acid Sequence↗
PubMedDate not supplied

[Burkitt's lymphoma of the appendix].

We report the case of a 12-year-old European boy presenting with an appendicular Burkitt's lymphoma. He complained of right lower abdominal pain mimicking acute appendicitis. Ultrasonography and abdominal CT showed an appendicular mass which features were strongly suspicious for malignancy. This case emphasizes the importance of medical imaging to characterize appendicular lesions and to select the surgical technique. Accurate diagnosis was obtained histologically on resected specimen.

Appendectomy↗
PubMedDate not supplied

An open multicentre study to evaluate the efficacy and tolerance of fluoxetine 20 mg in depressed ambulatory patients.

In this study, 544 out-patients suffering from depressive disorders were enrolled in 6 weeks open study with fluoxetine 20 mg. A statistically significant decrease of the Hamilton Rating Scale for Depression (HRS-D) score is observed during treatment. All individual item HRS-D scores and in particular suicidal ideation, sleep disturbances and anxiety showed the same improvement. Side-effects were carefully recorded and presented a lower incidence rate than in other studies. New issues in methodology management concerning ambulatory studies are discussed.

Adult↗
PubMedDate not supplied

A Belgian multicentre study of fluvoxamine in depressive outpatients.

Fluvoxamine, a new antidepressant that specifically inhibits serotonin reuptake, was studied in 272 outpatients in a six-week multicentre trial in Belgium. On the Hamilton Depression Scale, the mean score dropped from 25.2 to 8 after six weeks (p less than 0.00001). The Clinical Global Impression scores showed similar evolution. Fluvoxamine is a real antidepressant with a marked effect on mood. Its effective dosage is 100 mg to 200 mg/day. Its tolerance, notably at the cardiovascular level, is excellent.

Adult↗
PubMedDate not supplied

[Study of intravenous amitriptyline in acute depressions (author's transl)].

The author has performed an open study of 27 patients with an acute depressive state, hospitalized and treated with slow intravenous perfusions of amitriptyline. Similar perfusions of chlorimipramine act certainly more rapidly on depression, but conversion to oral dose raises some problems regarding active dosis. Intravenous amitriptyline reduces latency, is more sedative and without major intolerance, such as hemodynamic. Conversion to oral diffused forms (Redomex diffucaps) consolidates the results obtained by parenteral administration, and the antianxiety component permits the use of this drug in monotherapy.

Acute Disease↗
PubMedDate not supplied

Clinical trial with bromperidol in psychotic states.

The author has given bromperidol to a first group of fifteen patients with a clear psychotic condition, mostly of the schizophrenic type. The results of this study show that this neuroleptic drug possesses potent antipsychotic properties, being thus very interesting in the treatment of productive psychosis. Its antimanic activity is, however, not pronounced. Therefore, it is not indicated in agitation states requiring heavy and immediate sedation. The general tolerability of the product is excellent. Its side-effects are mostly of the extrapyramidal type, generally mild and easily controlled by antiparkinson medications. Bromperidol, given in one single daily dose, is well accepted by the patients. It is therefore a valuable addition in the neuroleptic therapy as concerns prevention of relapses in psychotic conditions. Its stimulating properties on activity, concentration and socioprofessional adaptation make it particularly adequate for readaptation programs.

Adult↗