Chevreul et les couleurs biologiques ou un rendez-vous manqué

There is another way to examine the relationships between colour and chemistry, which can be called «biological colours»: the dyes that are necessary for microscopical biology. In spite of his chemical education, Chevreul missed this important direction of research, for historical reasons due to the development of cellular theory in France

Evaluation of residual disease in b-cell chronic lymphocytic leukemia patients in clinical and bone-marrow remission using CD5-CD19 markers and PCR study of gene rearrangements

We evaluated minimal residual disease (MRD) in 23 CD5 + B-chronic lymphocytic leukemia (CLL) patients who achieved clinico-hematological remission confirmed by bone-marrow biopsy. MRD was evaluated by dual marker analysis flow-cytometry using CD5 and CD19 markers, and by the study of Ig heavy chain gene rearrangements using the fast polymerase chain reaction (PCR). According to our laboratory conditions patients were considered to be in complete phenotypic remission when total CD19 + cells were >25% and the ratio of CD5 + CD19 + /CD19 + cells was >25% According to these strict criteria only 9 of the 23 patients were in complete phenotypic remission. In order to evaluate the sensitivity of the above method, PCR analysis of the configuration of the Ig heavy chain gene region was performed in 12 of these patients. Five of 7 patients in complete phenotypic remission retained a detectable monoclonal rearrangement of the Ig heavy chain gene. For the remaining 5 patients in partial phenotypic remission, only one failed to show a monoclonal band and this is probably explained by the presence of an unusual gene rearrangement. In conclusion, this study suggests that PCR is more sensitive than dual marker flow-cytometry for evaluation of residual disease and that it is indeed possible to achieve complete remission at the molecular level, in B-CLL. Nevertheless, we suggest a word of caution as this was a retrospective study, and samples were not assessed before treatment. Thus the possibility that apparent molecular remission might correspond to unusual gene rearrangements cannot be completely excluded in these cases. © 1992 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Michel-Eugène Chevreul

Cent trois ans ! Une extraordinaire longévité a donné à Michel-Eugène Chevreul une stature scientifique et historique exceptionnelle. Père de la chimie organique, inventeur de nouvelles substances, cet homme de laboratoire sut appliquer ses connaissances scientifiques à la technologie des colorants et à la perception de la couleur. Du Muséum à l’atelier des Gobelins, il transposa la méthode analytique des corps gras aux phénomènes colorés. Sa renommée, consacrée par les formidables fêtes qui célébrèrent son centenaire, gagna l’Europe et le Brésil. Cet ouvrage constitue une synthèse originale sur l’oeuvre de Chevreul. Des spécialistes de la chimie des corps gras et des colorants, de l’épistémologie et de l’histoire des sciences, de la vision des couleurs, de l’histoire de l’art, des textiles et de l’architecture ont apporté des points de vue croisés sur les rapports de Chevreul avec la science et la technique, ainsi qu’avec la communauté scientifique et la communauté nationale du XIXe siècle