Search PubMed⌕ Search

Biomedical subjects

M Le Roch

Publications and source records attributed to M Le Roch.

6 recordsLinked to original sources
PubMed2001

Ofloxacin/beta-cyclodextrin complexation.

Ofloxacin (OFX) is a fluorquinolone characterized by photochemical instability. With the goal to improve its photostability in aqueous solutions, the complexation of ofloxacin with beta-cyclodextrin was investigated. The complexes showed a water solubility enhancement of approximately 2.6 times; nevertheless, the photodegradation of ofloxacin was not reduced. The complexes obtained were characterized by thermal and 1H nuclear magnetic resonance (NMR) analysis, which revealed an interaction between ofloxacin and beta-cyclodextrin. The last analysis indicated that only partial inclusion of the N-methylpiperazinyl moiety occurred, which can explain the fact that photostabilization was not improved. This partial inclusion phenomenon could be explained also by computer-aided molecular modeling.

Anti-Infective Agents↗
PubMed2001

Solid phase synthesis of sulphonamides: novel ligands of 5-HT6 receptors.

Using solid phase synthesis techniques, we have rapidly obtained a series of eight aryl sulphonamides derived from putrescine. These conjugates with various aryl groups were evaluated for their affinity towards 5-HT6 receptors in man. This evaluation revealed the interest of two compounds which present the same activity level, in the submicromolar range, as two reference derivatives. The most potent will be considered as a new lead for further investigations.

Humans↗
PubMed1999

Toxicity and osmoprotective activities of analogues of glycine betaine obtained by solid phase organic synthesis towards Sinorhizobium meliloti.

Seven analogues of the bacterial osmoprotectant glycine betaine (GB, trimethylammonioacetate), in which the methyl groups of the Me3N+ moiety are replaced by various substituents, were obtained by SPOS using Wang resin. Their biological activities (osmoprotection vs toxicity), appeared closely related to their uptake efficiency and their catabolism in the betaine-demethylating model bacterium Sinorhizobium meliloti.

Betaine↗
PubMed1999

Molecular analysis of the combining site of a monoclonal antibody against spermine.

The structural basis of the binding of the polyamine spermine to the monoclonal antibody SPM8-2 was studied using computer modelling, ELISA methods and chemical modifications of the binding site residues. Paratope modelling showed that the antibody combining site forms a highly negatively charged cavity mainly shaped by aspartic acid and tyrosine residues which contact the tetra-positively charged spermine molecule by electrostatic interactions and hydrogen bondings. The importance of the electrostatic environment for spermine binding to SPM8-2 is emphasised by the strong dependency on pH and ionic strength. Specific chemical modifications of carboxylate groups and tyrosine residues of the antibody adsorbed to microtiter plates resulted in decreased binding of the N1-biotin-spermine conjugate used to monitor the activity of the antibody. These observations are consistent with a key role of aspartate and tyrosine residues in complex formation with spermine. These studies, important to our understanding of antibody-hapten specificity, may also shed light on important motifs responsible for protein-polyamine interactions.

Amino Acid Sequence↗