Biomedical subjects

R Mazo

Publications and source records attributed to R Mazo.

7 recordsLinked to original sources

PubMed1999

[Effects of experimental vasectomy on testicular structure: ultrastructural study].

We have performed experimental vasectomies in dogs in order to study effects of vas deferens ligature with close technique, on the testicular ultrastructure. We point out the existence of alterations: structural changes of the seminiferous epithelium, great extracellular spaces which are generated for the premature exfoliation of germinal cells, degeneration of the germinal shock cells, the appearance of immature germinal cells and multinucleate spermatids in every stages of the spermatogenesis, the fall of mature spermatozoid number, thickening of basal membrane, relative increase in the Sertoli's cells size as well as their phagocytic function, and existence of spermaphagos unfasted into tubular lumen. The Leydig's interstitial islets show an absolutely normal cellular and vascular configuration.

Animals↗

PubMed1999

[Experimental vasectomy: comparison of epididymal structure with various surgical techniques].

OBJECTIVE: To analyze the effects of different surgical techniques of vasectomy on the epididymal structure. METHODS: Experimental vasectomies were performed in dogs using the conventional and open-ended techniques. The animals were orchidectomized 1 to 12 months after vasectomy and the epididymal structure was analyzed. RESULTS: The epididymal structure of dogs submitted to the conventional technique showed marked ectasia, reinforced basement membrane, loss of stereocilia in the principal cells, and formation of spermatic granulomas in interstitial tissue. At 12 months the principal cells showed signs of degenerative changes. In the different time periods analyzed in the study, no changes were observed in the epididymal structure of dogs submitted to the open-ended technique. CONCLUSIONS: The changes observed in the principal cells are ascribable to the increased intraluminal pressure produced by ligation of both ends of the vas deferens (conventional technique), since no changes were found in the epididymal structure of dogs submitted to the open-ended technique, at least in the different time periods analyzed in the study.

Animals↗

PubMed1998

[Experimental vasectomy: comparison of the testicular structure with various surgical techniques].

We have performed experimental vasectomies in dog in order to study different repercussions of various surgical techniques on the testicular structure. The closed technique, with ligature of both cut ends of the sectioned vas deferens caused a severe tubular atrophy, which finally destroyed the architecture of the testis with compensating hypertrophy of the intertubular connective tissue. The technique of the "open cut end", leaving the proximal end free and allowing the normal drainage of the vas deferens into the interstitial space of the spermatic cord, had not any influence on the testicular-structure, at least in the studied period of time, now one year. We can't reject any long-term immunological phenomena. The conclusion of this study is that the peculiarities of the surgical techniques of vasectomy have a decisive influence on the preservation of the testicular structure.

Animals↗

PubMed1998

[A morphological and morphometric study of the testicle in the rat vasectomized by electrocautery technics].

OBJECTIVE: To evaluate the influence of vasectomy by different fulguration methods on the rat testicular structure. METHODS: Experimental vasectomy was performed in Wistar rats by means of the Shapiro and Silber, and the Schmidt cauterization techniques. The animals were orchidectomized between 7 days and 9 months following vasectomy. A morphological and morphometric study of the rat testes was performed. RESULTS: We have observed that both cauterization techniques do not produce sequelae in the rat testicular structure and its morphology is compatible with the normal. The morphometric study showed that both techniques produced a significant decrease (p > 0.05) of the area occupied by seminiferous epithelium within one month post-vasectomy; however, these values returned to normal three months thereafter. CONCLUSIONS: Vasectomy by different fulguration methods does not change the rat testicular structure.

Animals↗

PubMed1997

[Effects of vasectomy on the testicular structure of the dog].

Study of the effect on testis structure in the dog caused by a vasectomy. Emphasis is made on how in animals undergoing ligature of both ends of the ductus deferens, existence of structural changes, which are consistently present, are proportional to the time elapsed from performance of vasectomy. Such changes are revealed by: degeneration of germinal epithelium, thickening of basal membrane and hypertrophy of interstitial tissue at the expense of unspecific connective tissue. Changes were first seen as from the fourth month, but a full year has to elapse prior to noting a marked germinal hypoplasia. These experimental results cast doubts on the safety of such sterilization approach, although they cannot be entirely extrapolated to humans.

Animals↗

PubMed1990

The role of yohimbine for the treatment of erectile impotence.

A double-blind crossover study of yohimbine vs. placebo was carried out in 40 patients. Eleven of 33 patients (33%) who completed the study had subjective improvement of erection while taking yohimbine alone, five of 33 (15%) responded while taking both yohimbine and placebo, five of 33 (15%) responded to placebo alone, and 12 of 33 (36%) responded to neither. Of 215 impotent patients subsequently treated with yohimbine, 38% reported some subjective improvement, but only 5% were completely satisfied. The physiologic response of yohimbine appears to occur in the central nervous system. Recent experience suggests that the typical dose has little side effect and higher doses achieves better results, but this conclusion requires more evaluation.

Administration, Oral↗

PubMedDate not supplied

The vasectomized testis.

We have performed a qualitative study on effects of vasectomy on the testicular structure. Vasectomy performed with the traditional technique changes testicular structure. At first, the injuries are slight and restricted, but gradually, and in a time-dependent manner, become more severe and extensive. Ultrastructure studies indicate that the spermatogonia and Sertoli's cells are the most resistant to vasectomy, and are even observed in some regenerating testes lacking a complete germinal epithelium. Morphometric studies revealed a decrease in epithelial depth, an increase in the thickness of the basement membrane and in surface of the interstitial space, all significant (P < 0.01) with respect to the control. However, the percentage of the interstitial tissue occupied by cells, did not show any significant difference. We propose that the increase of intraluminal pressure is the essential factor that provokes testicular atrophy.

Animals↗