Effects of anaesthesia and chronic catheterization on circulating levels of prostaglandins (PGE2 and PGF2a in dogs

Summary Chronic catheterization of aorta and inferior vena cava in dogs did not significantly affect circulating levels of prostaglandins (PGE₂ and PGF_2a ). Pentobarbital (30 mg/kg i.v.) anaesthesia produced a significant decrease in PGF_2a .This work was supported by INSERM (grant No. 76.5.183.5).We wish to thank Miss Laure Eloy and Mrs Annick Soubrier for their technical assistance.     

The effects of intraventricular injection of 6-hydroxydopamine on the sleep of kittens during development]

Intraventricular injection of 6-hydroxydopamine does not modify the states of alertness in the Kitten, if it is performed in the first week of postnatal life. At three weeks of age, it induces the same sleep impairments as those observed in the adult Cat. Therefore, in the immediate postnatal period, sleep control is not achieved through the monoaminergic systems.     

Degradation of type I collagen fibrils synthesized by human dental pulp cells in explant culture exposed toActinomyces viscosus. Electron microscope immunotyping

Summary Actinomyces viscosus Be 66, added to pulpal cells in culture, does not cause apparent cellular damage. The extracellular matrix consists of altered collagen fibrils and thin filaments, immunochemically identified as type I collagen. They probably represent the first steps of collagen degradation.This work was supported by INSERM (ATP: 77-85) and CNRS (RCP: 533).     

Bacillus thuringiensis delta-endotoxin: evidence that toxin acts at the surface of susceptible cells

Enzymically activated delta-endotoxin of Bacillus thuringiensis covalently bound to Sephadex beads, has the same effect on insect cells in tissue culture as free toxin. The effect is prevented by antitoxin antibody and heat denaturation and is not due to a nonspecific protein effect, the beads, or toxin released from the beads. The toxin, therefore, probably acts at the cell surface.     

delta-9-Tetrahydrocannabinol (THC) inhibition of the membrane transport system for thymidine]

THC decreases 3H-thymidine uptake within 15 sec. after addition of the drug to the culture (L1210 murine lymphoma cells and human lymphocytes). Experiments performed at 0 degrees C indicate that THC has no action on thymidine binding to the carrier. THC in micromolar concentration inhibits DNA synthesis through a alteration of membrane configuration.     

Inclusion of Gross virus cell surface associated antigen in liposomes]

The Gross virus associated cell surface antigen GCSAa was extracted from (C58NT)D cells by solubilization of membranes with detergent and partially purified. This antigen was entraped in liposomes. Absorption experiments of the cytotoxic activity towards EmaleG2 cells of a W/Fu anti (C58NT)D serum showed the presence of the antigen at the surface of sensibilized liposomes.