615 resultados para TESTIS


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Selective chemical sympathectomy of the internal sex organs of adult male rats was undertaken by long term administration of low doses of guanethidine. The spermatogenic activity of the testis was unaffected by treatment. Examination of the vas deferens using morphometric methods revealed a marked increase in luminal area in contrast to a decrease in muscle layer area and in epithelial height. This is morphological evidence of sperm accumulation caused by a disorder in ductal contractile activity. No structural changes were observed in the epididymis. However, the concentration of spermatozoa in the sperm suspension stored in the cauda epididymidis was significantly increased in denervated rats. This result is discussed in terms of a sympathetic control of resorption mechanisms in the epididymis.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fifteen live adult male botos, or Amazon river dolphins (Inia geoffrensis), were examined using ultrasonography during the yearly capture expedition, between October and November 2005, at the Mamiraua Sustainable Development Reserve, within the Brazilian Amazon (3 degrees S, 65 degrees W). All examinations were performed with a Sonosite 180 plus ultrasound unit in conjunction with a 2- to 5-MHz multifrequency transducer convex array 180 Plus/Elite-C60. Age and maturity estimates were determined considering the body length, weight, and external characteristics. In all examinations, the testes were discerned by the presence of a hyperechoic central line, called the mediastinum testis, a landmark for their identification during ultrasonography. No significant differences in echogenicity were detected on the ultrasonographic appearance of the testes among the studied animals. On adult male botos, apparent parenchymal nodulation of the testis was observed on scanning in most of the animals and probably constituted evidence of reproductive maturity. Using the color Doppler technique, blood flow was detected along the mediastinum testis that progressively decreased toward the periphery of this organ. Little blood flow could be identified by color Doppler. Power Doppler allowed better accuracy to identify testicular vessels, their topography, and their differentiation from adjacent structures. Ultrasonographic examination provides useful data for morphologic characterization of the boto's testes. Examination using Doppler techniques was considered a valuable tool to evidence blood flow through the testicular parenchyma.

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Background Tumor markers are genes or their products expressed exclusively or preferentially in tumor cells and cancer-testis antigens (CTAs) form a group of genes with a typical expression pattern expressed in a variety of malignant neoplasms. CTAs are considered potential targets for cancer vaccines. It is possible that the CTA MAGE-A4 (melanoma antigen) and MAGE-C1 are expressed in carcinoma of the oral cavity and are related with survival. Methods This study involved immunohistochemical analysis of 23 patients with oral squamous cell carcinoma (SCC) and was carried out using antibodies for MAGE-A4 and MAGE-C1. Fisher's exact test and log-rank test were used to evaluate the results. Results The expression of the MAGE-A4 and MAGE-C1 were 56.5% and 47.8% without statistical difference in studied variables and survival. Conclusion The expression of at least 1 CTA was present in 78.3% of the patients, however, without correlation with clinicopathologic variables and survival. (c) 2011 Wiley Periodicals, Inc. Head Neck, 2012

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The factors that influence Leydig cell activity currently include peptides such as neuropeptide Y (NPY). In this work we investigated the ability of this compound, injected directly into the testes of adult male rats, to alter testosterone (T) release into the general circulation. At a 5μg/kg dose administered 1h prior to challenge with human chorionic gonadotropin (hCG, 1.0 U/kg, iv), NPY significantly (P<0.01) blunted the T response to this gonadotropin. The inhibitory effect of NPY was observed in animals pretreated with an antagonist to gonadotropin-releasing hormone or not, indicating that the decrease in plasma T found was most likely independent of pituitary luteinizing hormone. However, testicular levels of steroidogenic acute regulatory (STAR) protein or translocator protein (TSPO) in the Leydig cells did not exhibit consistent changes, which suggested that other mechanisms mediated the blunted T response to hCG. We therefore used autoradiography and immunohistochemistry methodologies to identify NPY receptors in the testes, and found them primarily located on blood vessels. Competition studies further identified these receptors as being Y(1), a subtype previously reported to modulate the vasoconstrictor effect of NPY. The absence of significant changes in STAR and TSPO levels, as well as the absence of Y(1) receptors on Leydig cells, suggest that NPY-induced decreases in T release is unlikely to represent a direct effect of NPY on these cells. Rather, the very high expression levels of Y(1) found in testicular vessels supports the concept that NPY may alter gonadal activity, at least in part, through local vascular impairment of gonadotropin delivery to, and/or blunted T secretion from, Leydig cells.

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NPY receptors represent novel molecular therapeutic targets in cancer and obesity. However, the extent of NPY receptor expression in normal human tissues is poorly investigated. Based on the role of NPY in reproductive functions, the NPY receptor expression was studied in 25 normal human testes and, additionally, 24 testicular tumors using NPY receptor autoradiography. In the normal testis, Leydig cells strongly expressed NPY receptor subtype Y2, and small arterial blood vessels Y1. Y2 receptors were found to be functional with agonist-stimulated [(35)S]GTPγS binding autoradiography. Full functional integrity of the NPY system was further suggested by the immunohistochemical detection of NPY peptide in nerve fibers directly adjacent to Leydig cells and arteries. Germ cell tumors expressed Y1 and Y2 on tumor cells in 33% and Y1 on intratumoral blood vessels in 50%. Based on its strong NPY receptor expression in Leydig cells and blood vessels, the normal human testis represents a potentially important physiological and pharmalogical NPY target.

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Cystic lesions in the testis of children are rare and in most cases benign tumors. However, a preoperative diagnostic work-up could contribute to planning the surgical procedure: orchiectomy in the case of potential malignancy or otherwise a testis-sparing approach. In this study we reviewed our recent cases of benign cystic testicular tumors and the corresponding literature. The different entities are presented with details of the diagnostic work-up, pathology and treatment of these lesions. In all presented cases, organ-preserving treatment was performed. This practice is to be recommended in the case of all prepubertal cystic testicular lesions.

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PURPOSE: We evaluated the long-term outcome after 1 cycle of adjuvant modified bleomycin, etoposide and cisplatin chemotherapy in patients who underwent orchiectomy for high risk clinical stage I nonseminomatous germ cell tumor of the testis. MATERIALS AND METHODS: Between 1995 and 1999 a consecutive series of 44 patients underwent orchiectomy for clinical stage I nonseminomatous germ cell tumor of the testis, followed by a single postoperative cycle of adjuvant modified bleomycin, etoposide and cisplatin for vascular or lymphatic tumor invasion, and/or a predominance (50% or greater) of embryonal carcinoma. RESULTS: Four of the 44 patients were excluded from analysis. Of the patients 35 had no evidence of disease at a median followup of 99 months (range 60 to 134). One patient with progression after 13 months showed complete remission after 3 cycles of salvage bleomycin, etoposide and cisplatin chemotherapy but he died of pneumonia 4 weeks after the third course. Two patients underwent orchiectomy for contralateral testis cancer at 18 and 42 months, respectively, followed by an additional 3 cycles of adjuvant chemotherapy. They remained relapse-free for 4 and 92 months, respectively. The former patient was lost to followup after 4 months. Two other patients were disease-free at 10 and 31 months, respectively, and were lost to followup thereafter. Late side effects were tinnitus in 3 patients and involuntary childlessness in 3, of whom 2 had cryptorchidism of the contralateral testis. Nine patients fathered children. CONCLUSIONS: One cycle of bleomycin, etoposide and cisplatin effectively decreases the risk of relapse in patients with high risk stage I nonseminomatous germ cell tumor of the testis. It has minimal side effects and can be a valuable alternative to retroperitoneal lymph node dissection.

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Cytochrome P450c17 catalyzes both 17alpha-hydroxylation and 17,20-lyase conversion of 21-carbon steroids to 19-carbon precursors of sex steroids. P450c17 can mediate testosterone biosynthesis via the conversion of pregnenolone to dehydroepiandrosterone (the delta(5) pathway) or via conversion of progesterone to androstenedione (the delta(4) pathway). In many species, the 17, 20-lyase activity of P450c17 for one pathway dominates, reflecting the preferred steroidogenic pathway of that species. All studies of recombinant human P450c17 and of human adrenal microsomes have found high 17, 20-lyase activity only in the delta(5) pathway. Because the 17, 20-lyase activities in both the delta(4) and delta(5) pathways for testicular P450c17 have not been directly compared, however, it is not known if the delta(5) pathway dominates in the human testis. To resolve this issue, we assayed the conversion of 17alpha-hydroxypregnenolone to dehydroepiandrosterone (delta(5) 17, 20-lyase activity) and of 17alpha-hydroxyprogesterone to androstenedione (delta(4) 17, 20-lyase activity) by human fetal testicular microsomes. We obtained apparent Michaelis constant (K(m)) and maximum velocity (V(max)) values of 1.0 microM and 0.73 pmol.min(-1). microg(-1) for delta(5) 17, 20-lyase activity and of 3.5 microM and 0.23 pmol.min(-1). microg(-1) for delta(4) 17, 20-lyase activity. Catalytic efficiencies, expressed as the ratio V(max)/K(m), were 0.73 and 0.066 for the delta(5) and delta(4) reactions, respectively, indicating 11-fold higher preference for the delta(5) pathway. We conclude that the majority of testosterone biosynthesis in the human testis proceeds through the conversion of pregnenolone to dehydroepiandrosterone via the delta(5) pathway.