Influence of the visual cortex upon collicular evoked responses in the rabbit.

In rabbit, the depression of the visual cortex by KCl showed an enhancement of the collicular evoked potentials. This enhancement revealed that the visual cortex had exerted a tonic type influence upon the superior colliculus.     

Experimental allergic encephalomyelitis in T-lymphocyte deficient rats.

Thymectomized, lethally irradiated rats reconstituted with syngeneic bone marrow were injected with rat brain in complete Freund adjuvant mixture. Both, they and sham-thymectomized, irradiated and bone marrow protected rats displayed a higher incidence of leg paralysis than normal non-irradiated animals. Thymectomy lowered the incidence of the disease.     

Gastric mucus effusion elicited by oral copper compounds: potential anti-ulcer activity.

In rats, both Cu(I) and Cu(II) show an irritancy profile not shared with Cu degrees or Zn(II) or Ni(II). The gastric response to Cu(II), i.e. copius fluid and mucus secretion, can protect the stomach from the acute ulcerative effects of aspirin or physical stress administered subsequently.     

Influence of castration and testosterone replacement on hypothalamic tyrosine hydroxylase activity in the rat.

Hypothalamic tyrosine hydroxylase (TH) activity of castrate rats is modulated by testosterone propionate (TP) in vivo. Kinetic studies revealed that both Vmax and Km were virtually unaltered for substrate tyrosine in the presence of an excess of DMPH4 cofactor. TP replacement to castrate rats increased the Km for added DMPH4 cofactor, while Vmax decreased. These results suggest that TP decreases TH activity of castrate rats by inhibiting the enzyme-reduced pteridine cofactor complex.     

Biochemical markers in the taxonomy of the Actinomycetales.

Useful biochemical markers for the classification of Actinomycetales are: 1. DL- or LL-diaminopimelic acid in the peptidoglycan, 2. sugar composition of polysaccharides, 3. fatty acid spectrum of cell lipids. The occurrence of various kinds of branched fatty acids and of unsaturated fatty acids is of special value.     

Direct fluorination of carcinogenic polycylic aromatic hydrocarbons. 6-Fluorobenzo(a)pyrene.

Xenon difluoride reacts with benzo[a]pyrene(BaP) in dichloromethane solution in an open system to give 6-fluorobenzo[a]pyrene. This method constitutes a direct route to fluorine substituted carcinogenic polycyclic aromatic hydrocarbons.     

Carotid chemoreceptor influence on the cardiac sympathetic nerve discharge.

Pure stimulation of carotid chemoreceptors induces, as a primary effect, the general spontaneous activation of both the cardioexcitatory and the cardioinhibitory medullary centres. These effects have been shown by keeping constant those parameters which, when modified, produced secondary effects hiding the investigated primary ones.