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Biomedical subjects

R Perez

Publications and source records attributed to R Perez.

At least 181 records · Page 10Linked to original sources
PubMed1979

Cultivation of Ureaplasma urealyticum in continuous culture.

Continuous culture of Ureaplasma urealyticum is reported with a steady-state cell biomass of greater than 10(6) cells per ml. Thus, large cell numbers can be easily obtained; in addition, the system provides a powerful means for exploring what nutrients(s) limits the growth yield of this organism. Urea is shown not to be the growth-limiting nutrient in conventional media, although when provided in excess it appears to be completely hydrolyzed.

Bacteriological Techniques↗
PubMed1979

A semiautomated procedure for rapid intrarectal instillation of fluids in the guinea pig.

A penumatic operated semiautomatic system was developed for the intrarectal instillation of solutions in the guinea pig. The apparatus permitted one person to inject large numbers of animals at considerable savings in time compared to manually operated syringe techniques. The procedure was shown to be both rapid and safe for administering solutions intrarectally in the guinea pig.

Animals↗
PubMed1976

Ultrastructural study of binucleation in cells of the rat adrenal glomerular zone after a prolonged low-sodium diet.

Binucleate cells have been found in the glomerular zone of the adrenal cortex in rats subjected to low-sodium diets. By considering the various possibilities for their production, both the findings of nuclei in process of constriction and nuclei identical in form, confronted and smaller in size than those of neighbour cells, are in agreement with an amitotic nuclear division as the possible mechanism for the formation of these cells.

Adrenal Cortex↗
PubMed1975

[Scintigraphy of the choroid plexus (choroid plexography)].

An increase concentration of pertechnate in the choroid plexus was demonstrated in 21 patients pretreated with tin pyrophosphate injected intravenously 24 hours before the examination. Using this technique, the choroid plexus are seen quite clearly, giving indirectly a picture of the intracerebral ventricles. A dynamic study was carried out in 12 patients, 3 of whom had abnormalities of the cerebrospinal fluid circulation demonstrated by isotope cisternography. The results obtained were characterised by a typical diphasic curve with variations in the pathological cases.

Brain Neoplasms↗
PubMed1975

[Value of calcium gluconate labelled with 99mTc in the detection of intracranial tumors].

In a preliminary communication, the authors compare the success coefficients of pertechnate 99m-Tc and of a new labelled molecule: calcium gluconate 99m-Tc, in a group of 32 patients. The results obtained showed the undoubted superiority of the gluconate in comparison with the pertechnate in the detection of intracranial metestases, and in particular those of the posterior fossa. It proved equally effective as bleomycin labeled with 57-Co. Amongst the other types of tumour studies, the use of the gluconate seems to be particularly indicated for neoplasms of the posterior fossa and in those close to the base of the skull and venous sinuses, given the marked reduction in "background noise" obtained when this method is used.

Bleomycin↗
PubMed1975

Hormonal steroids: effects on the vascular system.

An increase in the incidence of thromboembolic disorders has been associated with oral contraceptive use, though the causative mechanisms remain unclear. Our studies indicate that the contraceptive steroids, irrespective of the intermediary metabolic processes involved, cause changes in the surface charge characteristics of the blood vessel wall and blood cells in the following cases: (i) in experiments using dogs, the hormonal steroids result in a greater reduction in the pore surface charge of veins than in arteries; (ii) in rats, the current induced mesenteric occlusion times are significantly lowered following administration of combined contraceptives steroids; (iii) in humans, the electrophoretic mobilities of erythrocytes and platelets from women taking Ovral and Demulen are lower than in controls, and (iv) there is no significant alteration of plasma coagulation times of women who are on injectable progestin therapy. Demulen and Ovral appear to result in a slight decrease in activated partial thromboplastin times compared to controls.

Animals↗
PubMed1975

Effect of a long-acting estrogen on the pituitary response to LH-releasing hormone (38582).

The effect of Quinestrol, an estrogenic substance of long-lasting activity, on the pituitary responsiveness to LH-RH was studied in ovariectomized rats. Quinestrol administered as a single 200 pg-dose significantly augmented the pituitary response to LH-RH 36 hr, 9 days, and although not significantly, also at 24 days after its oral administration. No effect could be detected 36 days after its administration. At a 20 pg-dose Quinestrol significantly augmented the pituitary response to LH-RH only at the 36 hr-period studied, this effect not being apparent in later time periods.

Animals↗