Comptes rendus des seances de l'Academie des sciences. Serie D, Sciences naturelles最新文献

A single injection of naloxone (1 mg/kg s. c.) increased plasma baseline levels by 6 times for ACTH, 17 times for corticosterone, 3 times for LH and 2 times for testosterone. A concomitant ether-stress induced a further 6 fold increment in ACTH and an additional 2 fold increment in corticosterone, both hormones attaining their similar levels to those after ether-stress alone. On the other hand no further increment was observed for LH and testosterone, which actually were more stimulated by naloxone than by stress alone. The tonic inhibition exerted by endogenous opiates on ACTH and LH appears, therefore, to interfere with stress in a different way for the two neuroendocrine systems considered.

Burst forming units (BFU-E) from the blood of eight normal adults were grown in methylcellulose culture. Follow up of i and I antigens detected by an indirect immunofluorescence technique from the 9th to the 14th day of culture revealed that i antigen expression diminished while maturation proceeded. On the contrary 1 antigen expression increased meanwhile. Nevertheless, in addition to this maturation process, expression of i antigen must be determined by a regulatory mechanism operating during erythroid stem cell differentiation since a large proportion of immature erythroblasts at the 10th day of culture do not express i antigen.

Administered to eggs of Reptilia (Lacerta viridis and Anguis fragilis), cytosine-arabinoside induced numerous embryonic malformations, among which microphthalmia and limb deformities. On the other hand this drug delayed the retrogression of the apical ridge of the limb buds in Anguis fragilis.

In the badger a seasonal sexual rhythm of the plasma testosterone is observed. There is also a nycthemeral rhythm of the testosterone secretion; during the regressed period of the testis this rhythm is bimodal with testosterone peaks during the light phase of the day; during the active period and "activity rhythm" with many transitorys peaks during the dark phase is added.

HLA-A and B phenotypes of 105 patients suffering from malignant melanomas were determined, with special regard for metastatic form or relapse. A highly significant increase of the HLA-A9 antigen is seen (X2 = 17.47); such data had already been shown by van Wijek [2], but other authors did not find this abnormality when studying melanomas whose histologic form was not specified.

The proliferative capacity of Chick embryo fibroblasts was modified by Con A treatment. Con A decreased the growth of fibroblasts from young embryos (8 days), whereas the lectin stimulated the growth of fibroblasts from older embryos (16 days). This differential effect of Con A did not result from changes in cellular permeability to thymidine, but rather from Con A induced modifications of hexose transport. Changes in hexose transport would cause, as a response, parallel modifications in glycolysis and hence energy charge, which would alter proliferative capacity.

The dissociation of human adult liver parenchyma by collagenase followed by cell separation with centrifugal elutriation allows the Kupffer cells to be isolated. These cells, which may be maintained in culture, retain their main morphological and functional features.

The local cerebral glucose utilization was measured by the 14C deoxyglucose method during spontaneous periods of waking or sleeping in the free-moving Cat. During slow wave sleep there was a 49% increased glucose utilization in choroïd plexuses.

Intracellular recordings of postsynaptic potentials evoked in cerebellar Purkinje cells (PCs) by activation of the climbing fibers (CFs) have been obtained from 3 to 15 day-old Rats. The data presented confirm the multiple innervation of PCs by CFs on postnatal days 8-9, and demonstrate its existence at earlier stage (from day 3). The evolution of the precentage of multinnervated PCs and of the mean number of CFs collaterals per PC was followed until the monoinnervation was established on day 15.

In contact with a collagen gel, thyroid follicular cells form a basal pole. A monolayer, with the apical side facing the culture medium is formed when cells are seeded on a collagen layer. In contrast cells reorganize into follicle-like structures when they are embedded in the collagen gel. If vesicles which have their apical pole in contact with the culture medium are embedded in the gel, collagen-cell interaction induced the inversion of cell polarity giving follicular structures. In addition after being overlaid with a collagen layer, cells forming a monolayer reorgnaize into follicles. The apical pole is formed on the free surface of the monolayer or on the internal side of structures embedded in collagen which differentiate into follicles.