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At least 703 records · Page 39Linked to original sources
PubMed1999

[Leydig cell tumor: report of 2 cases].

Tumors from the gonadal stroma represent 4% among testicular tumors. Leydig cell tumors are the most common neoplasms among them and account for 1-3% of all testicular tumors. Two cases of testicular Leydig cell tumors in adult patients are presented. Presentation, diagnosis and therapeutic aspects are discussed. Both were treated with radical orchiectomy through an inguinal approach. Cas 1 was diagnosed in a cryptorchid testis and developed hepatic metastasis that were successfully treated with chemotherapy. Cas 2 was incidentally diagnosed on ultrasound. Both of them remain alive and free of disease.

Humans↗
PubMed1999

The role of Wilms' tumor genes.

The constitutional chromosomal deletion within the short arm of one copy of chromosome 11, at band p13, which often correlated with WAGR syndrome consisting of Wilms' tumor with aniridia, genitourinary malformation, and mental retardation, provided the first clue to the genetic events in the development of Wilms' tumor. WT1 gene is encoded by 10 exons, resulting in messenger RNA subject to a complex pattern of alternative splicing. WT1 gene encodes a zinc finger transcription factor, which binds to GC-rich sequences and functions as a transcriptional activator or repressor for many growth factor genes. WT 1 protein is mainly expressed in developing kidney, testis, and ovary, indicating that it is involved in the differentiation of genitourinary tissues, all thought to be the sites of origin of Wilms' tumor. The point mutation of WT1 results in Denys-Drash syndrome. The other Wilms' tumor gene, WT2 at 11p15.5, is linked to Beckwith-Wiedemann syndrome. The possibility that WT1 is involved in the etiology of rhabdoid tumor of the kidney was discussed. WT1 is expressed in immortalized hematologic cells such as EBV-LCL and hematologic malignancies, but not in PBL or IL-2L. High level WT1 expression in leukemia cells and a poor prognosis are linked in patients with leukemia, making the gene a novel marker for leukemia cells. A correlated expression between WT1 and mdr-1 in vincristine resistant cells indicates a close relation with multi-drug resistance and is a promising diagnostic marker for chemoresistance in hematologic malignancies.

Animals↗
PubMedDate not supplied

Neonatally administered diethylstilbestrol retards the development of the blood-testis barrier in the rat.

Newborn rats were treated with 10 microg of diethylstilbestrol (DES) on alternate days from the 2nd to the 12th postnatal day, and the testes were sequentially examined up to 105 days of age by light, electron, and confocal laser microscopy. In control rats, spermatozoa and step 19 spermatids were observed in stage VIII seminiferous tubules at 56 days of age. Spermatogenic cells in DES-treated rats differentiated normally from birth until 21 days of age, after which differentiation continued only to the pachytene-spermatocyte stage. From this age onward, spermatogenic cells older than pachytene spermatocytes were not found until 56 days of age. After this point, the cells resumed differentiation and finally became spermatozoa by 91 days of age; that is, 35 days later than control rats. Electron and confocal laser microscopy showed that in the normal rat, the formation of the ectoplasmic specialization between adjoining Sertoli cells was observed as early as 20 days of age. In contrast, the specialization was not formed until 56 days of age in DES-treated rats. Furthermore, the delay in functional maturation of this structure as the blood-testis barrier was confirmed by intercellular tracer experiments. It is clear that neonatal administration of DES delayed the establishment of the blood-testis barrier for 4 weeks. Consequently, during this period, pachytene spermatocytes were exfoliated from the seminiferous epithelium without completion of meiosis.

Aging↗
PubMed1987

Spermatocytic seminoma: a case report.

An 81-year-old man with a painless enlargement of the right testis which developed 11 years ago was treated with right orchiectomy without any combined therapy in 1981. This tumor pathologically proved to be spermatocytic seminoma. The patient has been well and has shown no evidence of recurrence for the past 5 years.

Aged↗
PubMedDate not supplied

[Destruction and regeneration of the seminiferous tubules after local x-ray irradiation of the testes of sexually mature rats].

It was established that the local X-irradiation (1000 R) of testes of the adult rats results a total destruction of seminiferous tubules. The restitution of the organ structure proceeds via formation of new seminiferous tubules in which spermatogenic epithelium later develops. Rete testis and germ cells preserved in its epithelium from embryogenesis are a source of regeneration material. The results obtained favour the suggestion about the dynamic structure of mammalian testis.

Animals↗
PubMed1986

[Induction of papilloma and carcinoma in the forestomach of mice by in vivo formation of N-3-methylbutyl-N-1-methylacetonylnitrosamine (MAMBNA)].

Forestomach papilloma and carcinoma, as well as liver lesion, were induced in mice by gavaging precursors of the new nitrosamine, MAMBNA (N-3-methylbutyl-N-1-methylacetonylnitrosamine) and NaNO2. The results were-similar to those in mice and rats fed on preformed MAMBNA compound. However, the induction of such tumors by in vivo formation of MAMBNA required longer time and much larger doses. Moreover, the lesions of epithelial hyperplasia in the urinary bladder, lymphoid tumor, intestinal carcinoma and interstitial-cell tumor of the testis also developed in some of the experimental animals. This may indicate that the intragastric synthesis of MAMBNA is less effective in the production of forestomach tumors in mice.

Animals↗
PubMed1985

The mammalian rete ovarii: a literature review.

The rete ovarii is the homologue of the rete testis. It develops from cells of mesonephric origin which immigrate into the developing gonad of the embryo. The mature form of the rete ovarii is generally found to be groups of anastomosing tubules lined by cuboidal or columnar epithelium. These tubules are usually located in the hilus of the ovary, but may extend through the medulla or be isolated in the mesovarium adjacent to the hilus. The rete is often continuous with the transverse ductules through which it contacts the longitudinal duct of the epoophoron. The rete ovarii is important in the control of meiosis in the maturing ovary. Cells of the rete ovarii differentiate to form granulosa cells as well. The rete is also credited with secretory capability, a hypothesis supported by the observation of secretory material in the lumina of the rete tubules in several species. Cysts have been observed in the rete ovarii of several species. The rete ovarii of the adult does not appear to be a functionless vestige as has been previously reported.

Aging↗
PubMed1984

[Relation between glutathione and cytoplasmic protein sulfhydryl groups in the rat: a rapid procedure for analytical determination].

A simple rapid determination of glutathione (GSH) and cytoplasmic protein bound SH groups (PBSH), appropriate to study their relationship in tissues, in rat liver, kidney and testis was developed. Hepatic GSH and PBSH were measured after treatment with methyl iodide (400, 800 mg/kg, after 0.5 h), diethyl maleate (2 ml/kg, after 1h), carbon tetrachloride (1.2 ml/kg, after 3 h), phenobarbital (80 mg/kg for 3 days). Methyl iodide and diethyl maleate showed a decrease of GSH and PBSH; after treatment with phenobarbital an increase of GSH and PBSH was observed; no decrease of GSH and PBSH was found after carbon tetrachloride intoxication.

Animals↗
PubMed2002

The hormonal control of sexual development.

The formation of the testis or ovary is a critical step in development. The pioneering studies of Professor Alfred Jost showed that the hormones produced by the embryonic rabbit testis are essential for development of the male phenotype. Sexually dimorphic hormones play a key role in the transition from an undifferentiated gonad into the mature testis and ovary. Marsupials, with their altricial young, provide an accessible model for the study of sexual differentiation because most of these events occur postnatally, while the young are attached to teats within their mothers' pouches. The relatively long time-course for the marsupial sexual differentiation has provided an excellent opportunity to correlate morphological changes with the genes and hormones that control them. Using this model species we have demonstrated that not all sexual dimorphisms are controlled by hormones. Virilization of the prostate and phallus is androgen dependent but appears to rely on circulating 5alpha-androstane-3alpha, 17beta-diol which is converted to dihydrotestosterone in these target tissues. Collectively these studies have led to the development of new paradigms to explain the hormonal mechanisms mediating sexual differentiation.

Animals↗
PubMed2000

Evidence for the presence of 5'-deiodinase in mammalian seminal plasma and for the increase in enzyme activity in the prepubertal testis.

Thyroid hormones are critical for structural and functional development of the testis and Sertoli cells are considered true target cells for triiodothyronine (T3). However, the role of thyroid hormones in the adult testis seems to be minimal and the mechanism by which they affect testicular function is not known. Due to the existing blood-testis barrier the concentration of thyroid hormones in seminal plasma is kept lower than in blood plasma. We have found that T3 may reach the testis not only from the circulation but also from local enzymic conversion of thyroxine to T3. The presence of the enzymic activity responsible for thyroxine 5'deiodination and for generating T3 locally was also found in boar's seminal plasma. The seminal plasma 5'-deiodinase (5'-D) appeared to be predominantly the propylthiouracil (PTU)-insensitive type II isoenzyme found, so far, in tissues where it plays a role in paracrine signalling. It contains selenocysteine in its molecule (inhibition by aurothioglucose), and has an apparent Km for reverse-T3 as substrate of 0.36 nM and a Vmax 23.8 fmol I-/mg protein/min. Because the seminal plasma 5'-D is partially, but uncompetitively, inhibited by PTU, the presence in seminal plasma of two 5'-D isoenzymes (type I and II) cannot be excluded. The 5'-D activity in testes increased significantly between week 3 and 4, and this increase was concomitant with increase in testicular size. The relationship between testicular weight gain and age showed a similar characteristic change and corresponded to the change in 5'-D activity. Unlike in rodents, the testis of the prepubertal pig has thyroid hormone receptors in Sertoli cells, and suggests that in growing piglets, testicular 5'-D is a key factor regulating local supply of biologically active T3, and is an essential factor in testicular paracrine function. The present results are the first demonstration and characterization of the 5'-deiodinase in seminal plasma.

Animals↗