Testostérone circulante et cancer de la prostate. Revue de données récentes

In vitro andin vivo studies show that androgens stimulate prostate cancer. However, evidence from epidemiological studies of an association between circulating levels of androgens and prostate cancer risk has been inconsistent, but most studies have likely been undersized given that the association may be relatively weak. We review prospective studies on the association of serum levels of free and total testosterone, the principal androgen in circulation with risk of prostate cancer. No significant association between total or free testosterone and risk of prostate cancer was found in studies that together included 1,525 cases of prostate cancer and 4,349 controls. No support was found for the hypothesis that high levels of circulating testosterone within a physiological range stimulate development and growth of prostate cancer. Intraprostatic androgen metabolism may still be of importance for prostate cancer development.     

Potentialités autotoxiques et allélopathiques de Cistus albidus L.

This study focuses on how allelopathic mechanisms may be involved in the floristic composition and dynamics of Cistus albidus shrubbery. Allelopathic potential of essential oils was measured for Lactuca sativa (toxicity for other species) and Cistus albidus (self-toxicity). These oils have little effect on germination but significantly increase, even in low quantities, the number of unviable seedlings and inhibit normal seedling growth. These results explain, at least partially, the existence of monospecific stands over several years and the lack of natural regeneration of the Cistus albidus populations. Bioassays performed using natural aerial leachates of Cistus albidus revealed no significant effects on the above-mentioned parameters. Leaching does not seem to be an important means of allelochemicals release. Nevertheless, essential oils have been quantified in litter and soil, indicating a possible occurrence of allelopathy in such ecosystems.     

Arthrite rhumato?de juvénile et HLA-B27.

Forty children with juvenile rheumatoid arthritis were studied to determine the frequency of the histocompatibility antigen HLA [human leukocyte antigen)-B27 in this disease and to characterize the arthropathy associated with this antigen. HLA-B27 was detected in four patients (10%). Its presence was associated in a statistically significant manner with sacroiliitis demonstrated radiologically and with a greater age at the time symptoms in the joints first appeared; this age was, on average, 10 years, compared with 6.29 years for the children without HLA-B27.     

Les résidents et l'enseignement: revue de la littérature.

We reviewed the available data on residents'' teaching role in the clinical setting to develop programs to improve their teaching skills. Articles published from 1966 to 1989 were identified through a computerized search of MEDLINE, and the bibliographies of identified papers were reviewed. Articles directly related to the topic were included and analysed. Taking into account their quality, we extracted data relevant to specific issues. Approximately 15% to 25% of an average work week was spent by residents in different teaching activities. Students acknowledged the importance of their contribution to clinical teaching. Residents benefitted from teaching by increasing their medical knowledge and promoting the development of important attitudes. Insufficient preparation for this task and the numerous practical problems faced by residents may explain their modest performance as teachers. Nevertheless, programs directed to residents might improve the quality of their teaching. We suggest some guidelines for the development of programs to improve their teaching skills and for future research.     

La glomérulonéphrite de shunt: manifestations cliniques et histopathologiques.

In patients with cerebrospinal fluid internal shunts, immune complex glomerulonephritis sometimes develops. Of two new cases the first was classic, while the second was in an adult who had had a ventriculoatril shunt for 8 years; furthermore, the patient had acute renal failure and is the first to have been reported to have Peptococcus septicemia. Shunt glomerulonephritis is characterized by the following: (a) its occurrence following, most often, Staphylococcus albus infection in a patient who usually has a ventriculoatrial shunt; (b) transitory improvement of the symptoms by antibiotherapy only; and (c) full recovery if the prosthesis is removed. Laboratory studies show a low serum concentration of the C3 component of complement, the presence of cryoglobulins and a positive rheumatoid factor test. These abnormalities are reversible with removal of the prosthesis. Optical microscopy of a renal biopsy specimen in the two cases showed cellular proliferation of the glomerular tuft, electron microscopy demonstrated subepithelial deposits and immunofluorescent studies revealed intramembranous and intramesangial immune complexes. These features are similar to those observed in experimental nephritis induced in animals by foreign protein.     

Comparaison de l'état de conservation des phases minérales et organiques d'os fossiles. Implications pour les reconstitutions paléoenvironnementales et phylétiques

Bones have been collected from different geological sites, the sediment and the age of which being different. Comparizon between the mineral and organic phases shows the very fast alteration of the organic matrix in recent bones. Fossil bones show a loss in the organic matrices. Moreover, insoluble and soluble organic matrix alterations differ in a single bone. Implications of the diagenesis in palaeoenvironmental reconstruction and phylogeny are evoked.     

Obtention de lignées permanentes d'hémocytes de blatte. Caractéristiques physiologiques et ultrastructurales

Two new cell lines were established from larval and adult cockroach haemolymph. The cells show typical characteristics of plasmatocytes, but under different conditions of cultivation, they modulate from small dividing cells (prohaemocytes) to large storing cells (granulocytes, adipohaemocytes etc.). Consequently, the very confusing haemocyte nomenclature must be reconsidered taking into account the cell physiology. Biochemical analysis of the metabolized culture medium established bacteriolytic activity and chitinase secretion (two enzymes). Moreover, in the same medium we found a macromolecular factor inducing spermatogenesis in cultured germinal cysts of the Cynthia silkworm. All these characteristics of in vitro haemocytes are discussed to explain the involvement of blood cells in insect physiology and especially in immunity, gametogenesis, and ecdysis.     

Espaces de représentation et psychopathologie

A subjective world can be conceptualized as a “representational space” — that is, as a universe displayed from memory, in which the subject “is sailing”. Recent cognitive theory provides some conceptual tools for describing such a space in a relevant way for clinical purposes. The construction of a representational space is based on mental representations: (a) analogical representations, which display a content in working memory; (b) symbolic representations, which code and link up analogical representations to form a represented world. The dynamics of representations and affects is ruled by a principle of unification of representational space. The topology of a representational space depends on objective and subjective constraints which cause some “folds” and limit the display of such a space. The interaction between an event and a subjective memory can be analyzed within this framework, so that the concepts of trauma and defence processes can be defined. Clinical syndromes are defensive configurations that tend to close the representational space.     

Préhistoire et art rupestre dans le nord de l’Uruguay. De nouveaux programmes d’étude,de conservation et de valorisation

Since a few years, the study of prehistoric Uruguay and of its symbolical expression, rockart, has become a new subject of interest. Important programs of prospection, researches, protection and valorization of sites have been conducted, especially in the north of the country and contribute to the knowledge of an archeological heritage of an exceptional quality and a great density, that was until now unknown. Thanks to the international scientific cooperation and exchange program “ECOS-Sud”, the Department of Prehistory of the natural history national Museum of France (Paris) and the department of archeology of the Faculty of Human Sciences and Education of the Republic University in Uruguay (Montevideo), an important scientific and technical partnership have been set up. It reinforces and diversifies the existent links between our institutions and more generally between France and numerous countries of South America.     

Malladaites nov. gen. et Spinammatoceras (Hammatoceratidae,Ammonitina) de l'Aalénien de la zone subbétique,Sud de l'Espagne

The aim of this paper is to remark some morphologicaldifferences among the type-species of the genus ZurcheriaDouvillé and those species attributed to this genuf by Buckman & Brasil: the group of H. pugnaxVacek for which Schindewolf (1964) defined the genus Spinammatoceras, and the group of H. pertinaxVacek for which we propose Malladaites gen. nov.; new species of both genera are described. The stratigraphical range of these species is established in the Betic Cordillera.     

Ultrastructure des disques de patte de drosophile cultivésin vitro. Evagination,sécrétion de la cuticule nymphale et apolysis

Summary Ultrastructural observations were made on imaginal leg discs ofDrosophila cultured in vitro in Mandaron's medium M in the presence of - or -ecdysone.During evagination of discs in vitro the tight epidermal folds of the disc flatten out progressively and the cells change their shape.As the discs evaginate, the pupal cuticle is secreted at the apex of the cells: it comprises a three-layered cuticulin, an epicuticle and a thick endocuticle. Secretion of pupal cuticle always starts by the appearance of dense deposits at the apex of microvilli. Only the latter apparently participate in the construction of the three successive layers of the pupal cuticle.During disc development an abundant rough endoplasmic reticulum is formed. Nuclei and nucleoli become progressively enlarged. At the same time, the nucleus, initially located near the base of the cell, moves closer to the apical cell surface. Microtubules become fragmented as soon as evagination begins and are reorientated parallel to the cell surface (i.e. parallel to the new long axis of the cell) at the end of evagination.

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Ce travail a été réalisé avec l'aide du CNRS (Action thématique programmée) «Différenciation cellulaire», contrat n^o A 6554324.

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Ce mémoire représente une partie de la thèse qui sera soutenue par l'auteur devant l'Université Scientifique et Médicale de Grenoble.     

Syndrome de klinefelter et conseil génétique

Klinefelter’s syndrome is a common sex chromosomal aberration generally characterized by hypergonadotrophic hypogonadism and azoospermia. However, spermatogenesis impairment is variable and severe oligozoospermia can be found in some men, particularly those exhibiting a mosaic karyotype 47,XXY/ 46,XY. New reproductive technologies, such as intracytoplasmic sperm injection (ICSI), allow Klinefelter patients to have a progeny, even those who are azoospermic after testicular sperm recovery. The question therefore arises of whether or not there is a genetic risk for pregnancies from affected fathers. Sperm karyotyping, by in vitro penetration of zona-free hamster eggs or by fluorescence in-situ hybridization (FISH), is a method of choice for measuring aneuploidy rate in spermatozoa of patients carrying gonosomal abnormalities. A theoretical model would predict a high level of 24,XX and/or 24,XY disomic sperm cells in Klinefelter patients if 47,XXY spermatogonia were able to complete meiosis and achieve spermatogenesis. Interestingly, current observations show that the rate of abnormal spermatozoa in these patients is low, around 1–2%, which indicates that only 46,XY spermatogonia can produce mature sperm cells and that oligozoospermic Klinefelter patients probably carry a 47,XXY / 46,XY mosaicism, at least at the testicular level. However, this low but statistically significant level of disomic spermatozoa emphasizes the fact that their spermatogenesis occurs in a compromised environment which could increase the risk of meiotic errors. Therefore, the possible occurrence of autosomal aneuploidies in children born from Klinefelter fathers leads to the following recommendations: a) individual analysis by FISH of the sperm aneuploidy rate in each Klinefelter patient candidate for ICSI; b) proposal of fetal karyotyping after amniocentesis in pregnancies obtained by this technique.     

Le Genisteto-Carlinetum macrocephalae ass. nov. de l'étage montagnard et le Ligusticetum corsici ass. nov. de l'étage subalpin des Massifs du Cinto et du Campotile orientale

Sans résuméJe tiens à remercier M. le Dr.J. Braun-Blanquet de la généreuse hospitalité qu'il m'a offerte à la S.I.G.M.A. et des précieux conseils qu'il m'a dispensés pour la définition de ces associations. C'est la raison pour laquelle il m'a paru nécessaire de l'associer à l'une des Associations originales que j'ai décrites.Je suis également reconnaissant à mes amisM. et G. Roux d'avoir permis le traitement de mes données floristiques par l'analyse factorielle des correspondances.     

Variations des activités peroxydasique et phénoloxydasique au cours de la croissance de Coleus blumei Benth. var. Automne

Summary The specific peroxidase (1.11.1.7) and phenoloxidase (1.10.3.1) activities are quantitatively measured during the life of Coleus, from germination until flowering. In most organs investigated, the peroxidase activity increases rapidly with growth while the phenoloxidase activity remains low. The latter activity is higher in root apices than in more differentiated regions of roots. From the results obtained it may be concluded that the phenoloxidase activity accompanies cellular proliferation. It is suggested that the peroxidase activity plays an indirect role in root initiation through its role in cellular differentiation.

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Extrait d'une thèse de doctorat soutenue à la Faculté des Sciences de l'Université de Liège.