Sur la résistance deRickettsiella melolonthae Krieg aux antibiotiques

Zusammenfassung Rickettsiella melolonthae Krieg unterscheidet sich deutlich von den andern Rickettsien durch seine Verh?ltnis mit Beziehung zu Antibiotika und zwar durch seine Resistenz gegen Tetracycline.

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Je remercie vivement le professeurP. Giroud de l'Institut Pasteur pour ses conseils et l'intérêt qu'il a manifesté à ces rechereches.     

La teneur en proline et la résistance des plantes aux sels

Application of sodium chloride to crop plants in the culture medium leads to an increase in their endogenous content of free proline. There is a certain concentration of sodium chloride above which the proline content of the plants strongly rises (critical point). A relationship between endogenous sodium and proline contents could be found. In salt-sensitive plants (wheat) the critical point lies below that of salt-tolerant plants (barley). The critical concentration is not changed by certain alterations of the culture medium. The determination of the critical point by means of measurement of the proline concentration served as a basis for the analysis of the salt tolerance of crop plants.      

Scintigraphie de perfusion cérébrale positionnelle : résultats physiologiques et applications cliniques

To assess the impact of standing on brain perfusion, 125 brain perfusion scans in the upright and supine position were performed, including 108 patients. Perfusion values were compared using a relative quantitative approach and a segmentation of vascular territories with the help of an atlas of brain perfusion. We found a change in the distribution of the perfusion in favor of the vertebro-basilar system in the upright position. We discuss the case of a patient whose symptoms could be explained with the help of the comparison of brain perfusion scans in the upright and supine position. Atheromatous and post-dissection stenosis and their influence on perfusion are also discussed.     

Étude de la pyrroline déshydrogénase et de la régulation du catabolisme de l'arginine et de la proline chez Bacillus subtilis

Two different enzymes which catalyze the same reaction may be induced in Bacillus subtilis. This reaction is the oxidation of Δ¹-pyrroline-5-carboxylic acid in glumatic acid. The difference between the two enzymes is shown by the study: (1) of their thermostability, (2) of their chromatographic behaviour on columns of DEAE-cellulose, (3) of their kinetic characteristics.The results obtained from mutants and the induction phenomenon are interpreted according to the ideas of Jacob and Monod on enzymic regulation.The present paper also completes the results concerning the characteristics of the two inductible enzymes.     

Quelques considérations sur l'enseignement de la médecine physique et de la réhabilitation

Particularly since World War II physical medicine and rehabilitation have assumed a growing importance. The efforts of the Canadian Association of Physical Medicine and Rehabilitation, following a survey of Canadian universities, to increase the theoretical and practical teaching of physiatrics are emphasized. It is considered important that the teaching of physical medicine and rehabilitation should be carried out concurrently with other medical and surgical teaching programs. Paramedical and auxiliary rehabilitation personnel should participate in the teaching program. The number of hours devoted to physiatrics should be increased, and the medical student should be permitted to choose physical medicine and rehabilitation as a part of his internship program.     

Observations sur la spécificité de la coloration aux acides phosphotungstique et phosphomolybdique

Résumé Les Auteurs ont démontré que, en conditions histochimiques sur du matériel fixé au formol, les acides phosphotungstique et phosphomolybdique ont une double action: 1. une action oxydative à la charge des radicaux PAS-positifs (vic-glycols et éthyleniques) en milieu aqueux, et à la charge des radicaux aminiques en milieu anhydre; cette action entraine la transformation de ces radicaux en aldéhydes; 2. la formation d'une liaison chimique entre les aldéhydes et les molécules des acides phosphomolybdique et phosphotungstique. — La coloration du collagène, au contraire, n'est pas due ni aux radicaux aminiques ni vic-glycols et implique un mécanisme encore inconnu.

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Observations about the specificity of staining of phosphotungstic and phosphomolybdic acid

Summary The authors demonstrated that phosphotungstic and phosphomolybdic acid applied to formol-fixed tissues explete two following actions: 1. An oxidative action on the PAS-positive radicals (double bonds, vic-glycols groups) if in water solution and on aminogroups if in anhydrous solution. This oxidation results in a production of aldehydic radicals 2. The formation of chemical bonds between the aldehydic new-formed groups and the molecules of phosphotungstic or phosphomolybdicacid.— However, the above mentioned mechanism of action is not applicable to the collagen staining for which a different explanation has to be supposed.

     

Prédiction de la réponse aux anticancéreux par analyse du transcriptome

Predicting drug response is a challenging problem in oncology. Between 1975–1985, important efforts were devoted to the generation of cellular assays able to predict, on an individual basis, thein vitro response of tumour cells to chemotherapeutic agents, but such methods could not be adopted in routine. New molecular biology techniques have been developed in order to identify the genes involved in drug sensitivity and resistance. The availability of techniques of gene expression profiling has allowed to establish correlations between gene expression and drug sensitivity of tumour cells or human cancers. This type of approach has been initiated onin vitro systems by the National Cancer Institute (NCI) in the USA and is pursued by a growing number of public and private laboratories around the world. In the clinical setting, gene expression profiles are currently developed for the diagnosis and overall prognosis of human cancers, but should rapidly allow the prediction of drug response, so that clinicians would be able to prescribe individual treatments on a rational basis.