[The absence of infection with the human immunodeficiency viruses type 1 and 2 in an African Masai population].
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Biomedical subjects
Publications and source records attributed to J V Beneit.
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The hepatic metallothionein was isolated and partially purified from rats treated previously with stable Cl2Cd and Cl2Cd109. The livers were subjected to the extraction of proteins of low relative molecular weight by heat, ammonium sulphate, Sephadex G-25 and Sephadex G-75. The partially purified extracts were subjected to the pharmacological activity test on isolated mouse vas deferens. A specific effect on the norepinephrine synapsis was obtained through an increment of the answer to the electric stimulus. The mechanism of action could be explained by the increase of the calcium permeability through the membrane or by the increment of the norepinephrine presynaptic release.
The results obtained with a standard patch test series in a group of agricultural workers is compared with a control group. Statistically significant differences in the frequency of several allergens were found. The possible causes of these differences are discussed.
The effect of castration and treatment with testosterone propionate (PT), estradiol benzoate (E2) and ciproterone acetate (CPA) on the responses of the vas deferens in rat has been studied. Castration produces a time-dependent decrease of the response amplitude. PT augments the response amplitude in normal rats and reverses the effect of castration. E2 augments the response amplitude in normal rats without modifying the castration effect. CPA does not change the response of the vas deferens. The results suggest that PT and E2 through possible different mechanisms, facilitate the transmission in rate vas deferens, whereas castration obstructs it.
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1 The effect of oxytocin was studied on the isolated vas deferens of the rat. 2 Oxytocin (25 to 200 mu/ml) reversibly reduced the contractile response induced by noradrenaline, dopamine and acetylcholine. 3 Oxytocin (400 mu/ml) abolished the response to potassium. 4 The contractions evoked in the vas deferens by field stimulation were also reduced by oxytocin (50 to 200 mg/ml). The inhibitory effect of the drug was related to the external calcium concentration. 5 It is suggested that oxytocin depresses the contractile responses in the vas deferens at least partly by reducing the availability of calcium from an extracellular source.
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Morphine pellet implantation in mice was demonstrated to diminish resistance to encephalomyocarditis virus infections. The variations in the response to three different interferon (IFN) inducers--Newcastle disease virus, Escherichia coli lipopolysaccharide and a tilorone analogue--were evaluated. A close relationship between morphine dependence and IFN response was detected. A clear inhibition in IFN induction appeared as a concomitant phenomenon with the syndrome of morphine dependence. In the response intensity, the mice strain tested was more important than the total drug dose in the pellet. This effect of morphine on IFN responses presented a characteristic age-related pattern and, perhaps, may also be influenced by the H-2 murine phenotype.