915 resultados para testicular germ cell tumors


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Este estudo se reporta às funções de células natural killer (NK), como adesão, lise e citotoxicidade e de subpopulações de células T em uma família com alta prevalência de pacientes com câncer e que apresentaram: glioblastoma, leucemia mielóide crônica, osteoblastoma, melanoma e carcinomas gástrico, pancreático e cólon retal. Quinze membros dessa família foram estudados, sendo 13 sadios, acompanhados por 5 anos e dois com câncer: glioblastoma e leucemia mielóide crônica. Duas pessoas sadias, no momento da avaliação, desenvolveram posteriormente osteoblastoma mandibular ou melanoma maligno. Como controle, foram avaliados 19 indivíduos saudáveis de faixa etária equivalente. A determinação de linfócitos T CD3+ e de suas subpopulações CD4+ e CD8+ foi realizada empregando-se anticorpos monoclonais e a atividade citotóxica de células NK, avaliada pelo teste de single-cell contra células alvo da linhagem eritroleucêmica K562. Os resultados mostraram que as percentagens de células T totais (CD3+), da subpopulação CD4+ e da relação CD4/CD8 foram significativamente menores nos indivíduos da família estudada em comparação aos valores observados no grupo controle. em todos os membros dessa família a percentagem de formação de conjugados entre células NK-células alvo foi inferior ao valor mínimo observado nos controles. Essa alteração poderia estar relacionada a defeito na expressão de moléculas de adesão, presentes na membrana de células NK, como provável causa das alterações funcionais dessas células. A herança dos mecanismos determinantes desta deficiência pode ser um fator de risco, com valor prognóstico para o desenvolvimento de cancer.

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The morphologic appearance and clinical behavior of the human urinary bladder papillary transitional cell carcinoma (TCC) probably result from a complex interaction between carcinogenic insults and host resistance during the patient's life. While the main recognized risk factors are of environmental origin (e.g. smoking), relatively little information exists about the susceptibility to TCC development. The human leukocyte antigen G (HLA-G) molecule plays an important role in immune response regulation and has been implicated in the inhibition of the cytolytic function of natural killer and cytotoxic T cells. Several lines of evidence indicate that HLA-G polymorphisms influence the expression level and production of different HLA-G isoforms. The aim of this study was to explore a possible influence of the HLA-G polymorphism on the susceptibility to urinary bladder TCC development and progression in smokers and nonsmokers Brazilian subjects. The HLA-G locus was found to be associated with susceptibility to TCC development and progression. The G*0104 allelic group (specially the G*010404 allele) and the G*0103 allele were associated with a tobacco-dependent influence on TCC development. The G*0104 group was associated with progression to high-grade tumors, irrespective of smoking habit, while the G*0103 allele was associated to high-grade tumor only in smoking patients. Our results are an evidence that the HLA-G locus itself, or as part of an extended haplotype encompassing this chromosome region (particularly the HLA-A given the high linkage disequilibrium observed between them in this data series), may be associated with TCC susceptibility and tumor progression, suggesting a tobacco-dependent influence of these polymorphisms.

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Approximately 10% of patients with gastrointestinal stromal tumors (GIST) develop other neoplasms, either synchronously or metachronously. In this report we describe coexistence of a gastrointestinal stromal tumor and a hepatic perivascular epithelioid cell tumor (PEComa) in a 51-year-old woman with no evidence of tuberous sclerosis. A subcapsular hepatic nodule (0.8 cm in diameter) was found during surgery for symptomatic gastric neoplasm (15 cm in diameter) arising from the lesser curvature. Both tumors revealed histomorphological and immunohistochemical features confirming a diagnosis of a small incidental hepatic PEComa and a high risky extramural gastric GIST, respectively. The patient remained disease-free 25 mo after surgery with no evidence of tumor recurrence or new neoplasms. To our knowledge, this is the first report of PEComa in a patient with GIST. Hepatic lesions detected synchronously or metachronously in patients with GISTs may represent histogenetically distinct lesions and should be sampled to confirm or exclude metastatic GISTs. (C) 2008 WJG. All rights reserved.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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In the bullfrog Rana catesbeiana, testicular weight is constant throughout the year, but the volume densities of germinative and interstitial compartments undergo inverse changes from winter (non-breeding) to summer (breeding). The occurrence of apoptosis in the seminiferous lobules of bullfrogs was investigated in these two periods using sections stained with haematoxylin and eosin (H&E), the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling) method and transmission electron microscopy. TUNEL-positive cells were observed in the seminiferous lobules, and ultrastructural morphological details confirmed the occurrence of cell death by apoptosis. In summer, the occurrence of several spermatogenic processes (in addition to spermiogenesis and spermiation), and then the overconsumption of Sertoli cell-derived pro-survival factors, could be responsible for the increased density of apoptotic cells. Alternatively, the low apoptotic frequency in winter could be related to the constant homeostasis in the germinative compartment given that most lobules are filled with primary spermatocytes. As volume densities of interstitial and germinative compartments undergo inverse seasonal variations through the year, the incidence of apoptosis (in summer) could play a part in controlling the spermatogenic process, maintaining the lobular size when interstitial tissue is maximally developed. In winter, the low apoptotic cell density leads to spermatogenic recrudescence and, thereby, the production of an adequate quantity of spermatozoa for the next breeding period. Thus, apoptosis may participate not only in the maintenance of spermatogenic homeostasis, but also in the cyclical control of the different spermatogenic processes according to seasonal changes of the testicular compartments as a whole.

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The RT of domestic quail from Italian variety showed mainly an albuginic pattern being represented by tortuous channels lined predominately by a simple cubic epithelium. RT channels extended along the testicular albuginea and penetrates into the epididymal region (ER) through its myoconnective matrix. Passageways were continuous to proximal efferent ducts of the ER. Epithelium lining ultrastructure of RT passageways showed some differences between the spring and the inactive phase at middle fall, concerning the quail testicular reproductive cycle. The features observed in RT epitheliocytes in fall were the low cytoplasmic electrodensity, paucity of supranuclear vesicles, which were abundant and variable in form and shape in spring, and some degenerative aspects of cell organelles mainly in ER lamellae. Moreover, presence of apical cytoplasmic extrusions were verified in the fall. No marked features were seen in the RT ultrastructure during the winter and summer comparatively to the active phase of spring.

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The swamp eel, Synbranchus marmoratus, is a freshwater protogynic diandric species. Primary males develop directly as males while secondary males arise from the sex reversal of females. Fishes from Argentine and Brazil inland waters were collected, examined and compared for this study. In order to characterize the interstitial testicular compartment, light and electron microscopy techniques and an enzyme histochemical examination for steroidogenic cells detection were used. The interstitial compartment of S. marmoratus is composed of Leydig and myoid cells, collagen fibers, blood cells, macrophages,and amyelinic nerves. At the ultrastructural level, no differences were observed in the interstitial tissue, either between specimens from the different sampling sites or between primary and secondary males. Leydig cells are present in all testes examined throughout the year. A cytoplasmatic reaction of 3beta-HSD was detected only in Leydig cells during sex reversal and in both type of males, mainly during the regressed and early maturation classes (autumn and winter). Leydig cells possess the typical fine structural characteristics associated with steroidogenesis. Furthermore, in both type of males, during sex reversal and after the spawning period, the number of granulocytes and macrophages present in the testes increased, suggesting that they could be involved in phagocytosis and resorption of damaged cells. (C) 2004 Elsevier Ltd. All rights reserved.