Étude de la cytodifférenciation du rein de l'Epinoche femelle après traitement par la méthyltestostérone

Résumé Au microscope électronique, l'action de la méthyltestostérone sur les cellules rénales de l'Epinoche femelle se traduit par une cytodifférenciation conduisant à la formation de cellules glandulaires muqueuses. Elle a lieu simultanément à deux niveaux distincts:Au niveau du tubule proximal, le premier signe visible de cytodifférenciation est une activation du nucléole, accompagnée par une augmentation de taille des cellules. Puis on assiste à un développement de l'ergastoplasme et de l'appareil de Golgi et à l'élaboration de deux types de sécrétions: d'abord des granules de 2000–2500 Å, ensuite des grains de mucigène typiques, qui subissent rapidement une transformation muqueuse.Une cytodifférenciation régressive intervient en même temps. Elle concerne la pinocytose apicale qui disparaît.Au niveau des tubules collecteurs, la cytodifférenciation se traduit par la formation d'un mucus hyalin d'origine golgienne. Elle s'accompagne également d'une disparition de la pinocytose.La méthyltestostérone est capable de provoquer, chez la femelle, une cytodifférenciation rénale identique à celle que l'on observe chez le mâle pendant la période de reproduction. La transformation muqueuse des cellules rénales est donc sous le contrôle de la seule testostérone, qui déclenche au niveau cellulaire un ensemble de processus conduisant à la formation de mucus.Au microscope électronique, on constate que l'élaboration de mucus prêt à l'excrétion est achevée au bout de trois jours dans les tubules proximaux alors que dans les tubules collecteurs elle ne demande que 24 heures.

---

Action of methyl testosterone on the cytodifferentiation of the kidney of the female three-spined Stickleback

Summary At the microscopic level, the action of methyl testosterone on the cells of the kidney of the female three-spined Stickleback gives raise to a cytodifferentiation which leads to the formation of mucous glandular cells. This action is evident at two different levels:At the level of the proximal tubule, the first visible sign of cytodifferentiation is an activation of the nucleolus, accompanied by a growth of the cell size. Then a rapid development of the ergastoplasm and the Golgi apparatus takes place, which leads to the elaboration of two types of secretory particles: granules of 2000–2500 Å in diameter appear first, then typical mucigen granules become visible. These latter undergo a rapid mucous transformation.A regressive cytodifferentiation occurs at the same time. It concerns the apical pinocytosis which disappears in the cells undergoing the glandular differentiation.At the level of the collecting tubules, the cytodifferentiation is characterized by the elaboration of a clear mucus which originates in the Golgi apparatus and migrates to the apex of the cells. A disappearance of the pinocytosis is also noticeable.In the kidney of the female, methyl testosterone induces a cytodifferentiation which is identical to that occuring in the male during the breeding period. So the mucous transformation of renal cells is under the control of a single hormone: the testosterone, which is able to give raise to a succession of phenomena leading to the formation of a mucous secretion.With the electron microscope, it is possible to demonstrate that three days are necessary for the elaboration of the mucus ready to be discharged in the lumen of the renal proximal tubules. In the collecting tubules, the reaction occurs more quickly, after only two days of treatment.

L'auteur tient à remercier Monsieur le Professeur E. Follénius pour ses conseils et son aide précieuse au cours de la réalisation de ce travail.     

Étude de la cohorte nord-finlandaise de 1966: facteurs prédictifs et conséquences de la schizophrénie

Subtle motor, emotional, cognitive and behavioural abnormalities are often present in apparently healthy children and adolescents who later develop schizophrenia. This suggests that some aspects of causation are established long before psychosis becomes manifest. We aim to assess the factors contributing to the development of schizophrenia focusing mainly on genetic factors, pregnancy and delivery complications, early development and scholastic performance, as well as later educational, social and health consequences. This is done by reviewing the Northern Finland 1966 Birth Cohort, its scientific activities, publications and work in progress.     

Synthèse et étude R.M.N. de disaccharides et trisaccharides dans la série du l-rhamnose

Various di- and tri-saccharides containing l-rhamnose were synthesized by condensation of 2,3,4-tri-O-acetyl- or 2,3,4-tri-O-benzoyl-α-l-rhamnopyranosyl bromide with an unblocked glycopyranoside. The determination of the anomeric configuration of l-rhamnose saccharides by n.m.r. is difficult because structure has a greater effect on the spectra than does configuration. The α and β configurations and the position of the substitution may be assigned from the chemical shifts of H-5 and CH₃. In all the compounds having a β configuration, a shielding of the methyl group and a deshielding of the H-5 proton have been observed as compared to the compounds having an α configuration. The H-5 proton and the methyl group of peracetylated, (1→3)-linked α-l derivatives always resonate at higher fields than the corresponding protons of (1→6)-linked α-l derivatives.     

Étude palynologique du pliocène de la côte d'azur (France) et du littoral ligure (Italie)

Pollen analysis of Pliocene marine clays in coastal Alps paleogulfs is supported by biostratigraphic records according to foraminifers and accessorily to nannoplankton. From the seashore up to elevated areas, the region was occupied by forests mostly constituted by Gymnosperms (Taxodiaceae particularly). The Lower Pliocene vegetation was also characterized by local differences related to the substratum. Pollen assemblages changed in the Earliest Piacenzian; this event is probably to be related to a climatic fluctuation already evidenced in the Northwestern Mediterranean region.     

Étude en microscopie électronique et par cytophotométrie à balayage de la structure et de la distribution de la chromatine dans les noyaux des cellules cartilagineuses deTriturus cristatus âgés au cours de la régénération

Résumé Les cellules cartilagineuses des membres postérieurs deTriturus cristatus en régénération après amputation, ont été étudiées en microscopie électronique et par cytophotométrie à balayage. Nous nous sommes intéressés à la structure et à la distribution de la chromatine mais aussi à différents organites cytoplasmiques. Dans l'étude de cytophotométrie à balayage, la chromatine a été considérée à travers son constituant majeur, l'ADN, coloré par la réaction de Feulgen. Au cours de la régénération du membre, l'hétérochromatine initialement condensée, essentiellement accolée à la membrane nucléaire se décondense. Les vacuoles du cytoplasme, caractéristiques des animaux âgés par rapport aux animaux jeunes, disparaissent, les mitochondries et le reticulum endoplasmique rugueux deviennent plus abondants. Les caractéristiques nucléaires de l'activation cellulaire apparaissent précocement, précédent les modifications cytoplasmiques et conduisent à des cellules en tous points identiques aux cellules d'animaux jeunes en dehors de tout processus régénératif. Cette phase d'euchromatisation et de restructuration cytoplasmique est peut-être nécessaire à l'accroissement d'activité métabolique et à la division cellulaire qui suivent. Son déroulement peut expliquer tout au moins le ralentissement de la régénération observé chez les animaux âgés par rapport aux animaux jeunes.

---

Electron microscopic and scanning cytophotometric study of chromatin structure and distribution in nuclei of cartilaginous cells of agedTriturus cristatus during regeneration

Summary Cartilaginous cells of aged newts (Triturus cristatus) were studied during hind limb regeneration. The electron microscope was used to study the structure and distribution of chromatin in the cell nuclei, while the DNA content of the chromatin was measured by means of a scanning cytophotometer.Changes in the ultrastructure of the cytoplasm during regeneration were also studied.It was observed that the structure and distribution of chromatin in the activated cell is greatly modified. In the non-activated cell of the aged newt, the chromatin is found highly condensed and distributed peripherally close to the nuclear membrane. In contrast, in the activated cells, the chromatin is much less condensed and is distributed throughout the nucleus. Moreover, cytoplasmic vacuoles, found only in the non-activated aged cells, disappear and an increase in the mitochondria and rough endoplasmic reticulum is also observed.Changes in the nuclear structure are observed prior to the cytoplasmic modifications.It is interesting to note that the process of activation induces structural changes in the aged cells which make these cells appear to be structurally identical to the young cells. This process of rejuvenation takes 3–5 days in the newt.We suggest that these structural changes of the chromatin and cytoplasm in the aged cells are necessary to increase the metabolic activity which precedes cell division. It may also explain why regeneration takes a longer time in the aged animals than in the young ones.

     

Les primates hominoides du Vallésien de Macédoine (Grèce). Étude de la machoire inférieure

The locality of the Ravine of the Rain is located in Lower Macedonia (Greece); it has yielded an important mammalian fauna of Vallesian age (Upper Miocene). An hominoid Primate is present with a lot of well preserved jaws. It is one of the better set of specimens never found in the same locality. His features and caracters are described and compared with those of the others tertiary Hominoids. This is a species which is near of Sivapithecus, Bodvapithecus and Ramapithecus and also it is very near of the ancestry of Gigantopithecus. All these Primates have had a particular ecology and this is probably the set in which we shall find the root of the plio-pleistocen Hominids.     

Les bases cytologiques de la théorie du ≪crossing-over≫: Étude sur la spermatogénèse et l'ovogénèse des calliphorinae

Sans résumé     

Apports de la géologie et de la géomorphologie à l’étude du mégalithisme : identifier,interpréter,dater

The contribution of geology and geomorphology to architectural and technological study of the Atlantic coast of France megaliths is important and can be grouped into three main axes: to identify, interpret and dating. Identification refers to the sourcing of the megalithic materiel from 0 to 7 km, sometimes around 10 km, or even exceptionally around 30 km. It is never the entire supply that is affected by such long distances but only a few blocks, some of them are remarkably well staged in the megalithic architecture. Another contribution lies in a fresh look at the management of stone recognized through the modes of acquisition, transformation and use of the raw material. More particularly, the geomorphology associated with technological reading offers tools for recognizing ancient standing stones. In the context of the interpretation of funerary chambers, the two sciences open a large window on the modalities of the internal structuring of monuments. From the entrance to the end of the chamber, the organization and use of the space is documented, sometimes a symbolic coding emerges from the mineral walls. This symbolic coding is based on particular petrography, on surface conditions operating a subdivision of space, on granulometries and homogeneities of differentiated surfaces. The internal organization can also be marked with natural “patterns”, which refer to a completely new aspect of Neolithic thought. Finally, the last axis concerns relative dating, by recognizing forms of postmegalithic fossil erosion, geomorphology makes it possible to identify reused stelae. A very important tool in a current research context where an important episode of reuse of standing stones at the end of the middle Neolithic is anticipated in the construction of dolmens in the south of France.     

Étude des activités osidasiques du tube digestif des adultes et des larves de la bruche du haricot,Acanthoscelides obtectus

Les larves et les adultes de la bruche du haricot se nourrissent de deux types d'aliments différents, mais proches en ce qui concerne la composition en hydrates de carbone: les larves consomment des graines de Phaseolus vulgaris et P. coccineus, les adultes s'alimentent principalement avec le pollen de diverses plantes.L'activité des larves et des adultes a été étudiée sur 22 substrats, en vue de préciser les caractéristiques de leur équipement osidasique. Les recherches ont montré que les larves et les adultes possèdent un équipement très important en - et -glucosidases, en - et -galactosidases, ainsi que des activités très importantes sur certains polysaccharides, notamment l'amidon et la pectine, mais l'activité est faible sur les hémicelluloses étudiées, notamment la xylane, l'arabinogalactane et la glucomannane. Les activités sur la carboxyméthylcellulose et la cellulose, ainsi que l'inuline, sont nulles.La corrélation étroite entre la composition en hydrates de carbone de la nourriture et les activités glycosidasiques du canal alimentaire chez les larves et les adultes permet une utilisation optimale des ressources trophiques en hydrates de carbone. Le parallélisme frappant entre le système glycosidasique des larves et celui des adultes a pour explication la ressemblance entre la composition en carbohydrates du pollen et celle de l'endosperme de haricot.

---

Summary Adults and larvae of Acanthoscelides obtectus eat two different types of food, similar in carbohydrate composition: larvae eat seeds of Phaseolus vulgaris and P. coccineus, adults eat principally pollen of various plants. The authors have studied the digestive activity of larvae and adults on 22 different sugars, in order to investigate activity of their glycosidase enzymes. Larvae and adults have a very important complement of - and -glucosidases, - and -galactosidases, and very high activity against certain polysaccharides, notably starch and pectin. The activity is weak on the hemicelluloses tested, notably on xylan, arabinogalactan and glucomannan. No activity is found on carboxymethylcellulose, cellulose and inuline.The close correlation between the carbohydrate composition of the food and the glycosidase activity of the alimentary canal in both larvae and adults enables optimal utilization of carbohydrate resources. The striking parallel between the glycosidase systems of adults and larvae is explained by the similar carbohydrate composition of pollen and bean endosperm.