Browsing by Author "BUSTOSOBREGON, E"

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    45 XO/49 XYYYY MOSAICISM IN A MALE WITH STIGMATA OF TURNERS SYNDROME
    (1983) PINCHEIRA, JV; BUSTOSOBREGON, E; PUMARINO, H; SANTOS, MA
    A male subject with Turner-like stigmata and chromosomic constitution 45,XO (97.5%) and 49,XYYYY (1.1%) is reported. The finding of a low percentage line bearing Y chromosome in a patient with clinical features similar to those described for XO males, would support the hypothesis that masculinization in certain individuals with 45,XO karyotype may be due to an undetected mosaicism.
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    ALKYLATING-AGENTS AND MOUSE SPERMATOGENESIS - EFFECTS OF A SINGLE DOSE OF CYCLOPHOSPHAMIDE
    (1985) VIGIL, P; BUSTOSOBREGON, E
    Cyclophosphamide (CFA) is one of the alkylating agents which has now been used with some success in the treatment of human neoplasias and renal disease. To evaluate how this drug could affect the seminiferous epithelium, a single dose of CFA (200 mg/kg per wt) was given to 20 adult mice (strain A/Sw). The effect of the drug was compared with a control group to which physiological saline solution was injected. Mice were sacrificed by cervical dislocation at 4 different time intervals after the drug administration to evaluate the action of the drug in different stages of spermatogenesis. The effect of the drug was appreciated as soon as 4 days after its administration. The initial damage to the epithelium was characterized by vacuolization of the Sertoli cells. Of all germ cells, primary spermatocytes showed the highest sensitivity to the drug. A high percent of teratozoospermia in the experimental group, when compared to the control group, was observed at all time intervals. The way CFA affects the morphology of mammalian spermatozoa and the usefulness of the animal model presented are discussed.
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    INHIBITION OF GROWTH AND DIFFERENTIATION OF FETAL HAMSTER GONADS GRAFTED INTO THE ADULT TESTIS
    (1988) ARRAU, J; BUSTOSOBREGON, E; CABELLO, R
    A cytomorphological analysis of the effect of adult testes on growth and differentiation of grafted fetal testis or ovaries was performed in hamsters. Fetal gonads, taken at 14 days post-coital age, were grafted for 30 days either under the renal capsule or testicular capsule of scrotal or cryptorchid tests of adult hamsters (weight 15 .+-. 23 g). Renal grafts were also performed in males castrated 30 days prior to receiving the fetal gonads. Growth and differentiation of the fetal gonads (testis or ovary) was totally inhibited by the scrotal testis. When the cryptorchid testis was the recipient of fetal gonads, inhibition was correlated inversely with the degree of spermatogenic damage elicited in the cryptorchid testis. No inhibition was observed in fetal gonads grafted under the kidney capsule, nor in castrated, normal or cryptorchid animals. As normal growth and differentiation of both testis and ovary occurred when grafted under the kidney capsule, the inhibitory effect of adult gonads seems to be unrelated to plasma testosterone levels in the host, as levels were undetectable in castrated hamsters and reduced drastically in cryptorchid animals. At the same time, the testicular-inhibiting substance in normal animals did not act at a distance, since it effect was restricted to fetal gonads grafted under the testicular capsule. This inhibitory subtance may correspond to the spermatogonial chalone, known to be produced by differentiating spermatogenic cells (mainly spermatocytes and round spermatids in the rat and mouse); these chalones prevent spermatogonial proliferation and, consequently, the critical number of spermatogonia needed to enter meiosis is not attained. It is doubtful if the same substance has the ability to differentiate the fetal ovary or if this effect can be ascribed to a more complex situation involving other testicular peptides of paracrine action and/or locally levels of androgens.
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    ROUND-HEADED SPERMATOZOA - A MODEL TO STUDY THE ROLE OF THE ACROSOME IN EARLY EVENTS OF GAMETE INTERACTION
    (WILEY, 1990) VONBERNHARDI, R; DEIOANNES, AE; BLANCO, LP; HERRERA, E; BUSTOSOBREGON, E; VIGIL, P