Long-term depressor effects of noradrenaline and dopamine neurons transplanted into the third ventricle of the brain of salt-loaded hypertensive rats

Neural tissues including A 6 group noradrenaline neurons in the locus ceruleus or A 10 group dopamine neurons in the substantia nigra were transplanted into the third ventricle at the preoptic-anterior hypothalamic level of rats made hypertensive by salt loading. Either transplant exerted a long-lasting depressor effect.     

External strontium and contractility in single giant muscle fibers of the barnacle

Summary Isometric tension and membrane potential in response to electrical stimulation have been studied on single giant muscle fibers of the barnacle upon replacement of external calcium with strontium. Under these conditions, the membrane response showed after the normal peak depolarization, a plateau phase lasting 3–7 sec before repolarization took place, while the force of contraction showed a linear relation with external strontium concentration. A direct action of strontium ions on contractile proteins (namely troponin) can be ruled out in favor of a triggering action on the sarcoplasmic reticulum, which, in turn, leads to calcium release and development of tension.Acknowledgment. I wish to thank Dr C. C. ashley in whose laboratory the research reported in this paper was performed, and Mrs L. M. Castell for invaluable technical assistance. This work was supported by grant No. 106140/048104235 from Consiglio Nazionale delle Ricerche, Italy.     

Interaction between sugars and amino acids in intestinal absorption by rat,in vivo

Summary The inhibitory action ofl-leucine on the intestinal absorption ofd-glucose andd-galactose, as well as the inhibitory action ofd-galactose on the absorption ofl-leucine at various concentrations by rat small intestine has been studied. The further effect was more clearly evidenced when the medium was perfunded through the intestine in a closed circuit system using a peristaltic pump.     

Inhibition of phorbol myristate acetate and phytohemagglutinin stimulation of human lymphocytes by 13-cis-retinoic acid and ethyl etrinoate

Summary The retinol analogues 13-cis-retinoic acid and ethyl etrinoate inhibit the mitogenic activity of phorbol myristate acetate and phytohemagglutinin on human lymphocytes. This inhibitory effect is greater against the stimulation with phorbol myristate acetate than with phytohemagglutinin.This work was supported by a grant from the National Cancer Institute of Canada. We would like to thank Hoffmann-La Roche, Canada, for providing the 13-cis-retinoic acid and the ethyl etrinoate.     

Optic microscope observations on changes in enamel and dentin induced by laser beams

By a laser beam, enamel and dentin are changed into an identical crystalline structure observed in reflected light and described as recrystallisation after fusion. The Vickers pyramidal numbers of these areas are the same as the mature enamel surface (590 VPN). The theoretical calculation proved that after irradiation in enamel there is an elevation of temperature about 2,5 degrees C through 3 mm. These observations suggest that new operative techniques might be possible.