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Biomedical subjects

C Viel

Publications and source records attributed to C Viel.

At least 73 records · Page 4Linked to original sources
PubMed1978

Methionyl-tRNA synthetase from sheep mammary gland. Purification of a fully active monomeric enzyme derived from high-molecular-weight complexes by controlled proteolysis.

Methionyl-tRNA synthetase from sheep lactating mammary gland is found predominantly in the form of high-molecular-weight complexes. Controlled proteolysis of these aggregates generates a low-molecular-weight species of the enzyme with full maintenance of activity as assessed by the rate of aminoacylation of tRNA. The product of proteolysis, which has been purified to homogeneity with a yield of 23%, is a monomeric enzyme of molecular weight 78 000. It has a specific activity of 405 units/mg at 25 degrees C. These findings clearly demonstrate that the aggregated state of methionyl-tRNA synthetase is not a prerequisite for full expression of catalytic activity. Furthermore, the results emphasize the need to provide effective protection against proteolytic damage in studies dealing with the characterization of high-molecular-weight complexes of aminoacyl-tRNA synthetases.

Amino Acyl-tRNA Synthetases↗
PubMed1978

[Azotized emetine analogues: synthesis and evaluation of the anti-amebic and anti-tumoral action of aza-3 emetine and attempted synthesis of aza-2 emetine].

The synthesis of the N,N-bis-(acetylhomoveratrylamido)-1-hydroxymethyl and 1-carboxypropylamines (III a) and (III b) is described. Until now, these molecules could not been cyclized to the corresponding isoquinoline compounds. An attempted synthesis of 3-azaemetine by condensing homoveratrylamine with acetonedicarboxylic acid or its esters did not yield the expected diamide (XIV). However, by subjecting 1,3-bis-(1,2,3,4-tetrahydro-6,7-dimethoxy-1-isoquinolyl)acetone (XV) to a reducing aminoalkylation, one obtained the corresponding ethylamino derivative (XVI) which could be cyclized through Mannich reaction to give 3-azaemetine. The pharmacological screening showed 3-azaemetine to be less toxic than emetine in the mouse and without antiamebic and antitumor activity against P 388 Leukaemia in the mouse (25).

Amebicides↗
PubMed1977

[New analogs of papaverine: synthesis, pharmacological and conformational study of benzyl-4-isoquinolines substituted in the 1 or 3 position].

The synthesis of p-chlorobenzyl-4-isoquinolines variously substituted in the 1 and 3 positions by condensation in an acid medium of the diethyl acetal of a substituted N-veratrylaminoacetaldehyde with p-chlorobenzaldehyde is described. Pharmacological and conformational tests have been carried in comparison with papaverine and p-chlorobenzyl-4-isoquinoline. The basicities of these derivatives have been measured and compared.

Animals↗
PubMed1975

[Research in antitumoral chemotherapy. X. Cytotoxic and antitumoral activity of beta-nitrostyrenes and of composed nitrovinyl derivatives].

In previous work the antitumoral cytotoxicity of beta-nitrostyrenes obtained by simplification of the aristolochic acid molecule was demonstrated. The effect of modifying the three characteristic parts of the beta-nitrostyrene molecule has now been investigated. The results obtained in vitro and in vivo allow hypothesis of a mechanism of action for the various beta-nitrostyrene and nitrovinyl compounds studied and definition of the maximum simplification compatible with retention of biological activity.

Animals↗
PubMedDate not supplied

Comparison of planar chromatographic methods (TLC, OPLC, AMD) applied to essential oils of wild thyme and seven chemotypes of thyme.

Essential oils analysis is more often realized by gas chromatography. However, thin-layer chromatography (TLC) remains the reference for Pharmacopoeia. Nevertheless classical TLC has its own limitations but it is always a good technique because it is simple, rapid and less expensive. Actually the reproducibility, the separation quality and the possibility to obtain good and reproducible quantitative determinations have been improved significantly with automated sample applicator, scanner densitometers and two new chromatographic planar methods: the optimum performance laminar chromatography (OPLC) and automated multiple development (AMD). In this work, we show and compare the performance of these methods and TLC through a study of seven thyme chemotypes and wild thyme essential oil.

Autoanalysis↗
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Awards and Prizes↗
PubMedDate not supplied

[The manipulation of information of developed formulas for the study of structure-activity relationships. Application to antiparasitic agents].

Beside traditional univariate methods of pharmacochemical (pharmacomodulation...), and of molecular pharmacology ("binding"...) most global approach (multivariate) of structure-activity and structure-toxicity relationships may been in action with processing implement. Developed formula may been treated by different algorithmic methods as molecular connectivity matrix which use atoms, bindings, chemical functions, fragments, of any molecule. This technique allows to research and to automatically count structural fragments of molecule, different in their chemical aspect but having the same port of activity. So, with this profile of fragments it is possible to build a spanning tree (PRIM'S arborescent skeleton) and to place a priori on it, new structures with other properties to value their activity level in the designed field. We applied these techniques to 50 most prescribed antiparasitic active principles.

Information Systems↗
PubMedDate not supplied

[Multivariate analysis as a means of access to optimal pharmacochemical specificity and to molecular archetypes].

For complex works as studies relationships structure-activity, in heterogeneous therapeutic families we have selected mathematical methods founded upon systemic approach rather analytic one, appealing to bibliographical data, taking into consideration a plurality of biological targets and envisaging structural extrapolations rather than interpolations. Compared with classical QSAR, multivariate analysis (factorial analysis and multidimentional data reduction) intend from structuration of whole complex items to definite spheres of correlations between structural parameters and biological ones to issue then on a symetric typology of this two groups of parameters. These approaches have not only a descriptive character but lead to operational conclusions through an interactive dialogue with data bank; for example: --to explore acting potentiality of others molecular families or/and particular sub-structures --to find chemical sequences of molecules synthesized for other aims but not again experimented for this property. The case of antiparasitic agents is here developed.

Analysis of Variance↗