Search results for "Seminiferous Tubules"
showing 5 items of 5 documents
Human endogenous retrovirus rec interferes with germ cell development in mice and may cause carcinoma in situ, the predecessor lesion of germ cell tu…
2005
Germ cell tumors (GCTs) are among the most common malignancies in young men. We have previously documented that patients with GCT frequently produce serum antibodies directed against proteins encoded by human endogenous retrovirus (HERV) type K sequences. Transcripts originating from the env gene of HERV-K, including the rec-relative of human immunodeficiency virus rev, are highly expressed in GCTs. We report here that mice that inducibly express HERV-K rec show a disturbed germ cell development and may exhibit, by 19 months of age, changes reminiscent of carcinoma in situ, the predecessor lesion of classic seminoma in humans. This provides the first direct evidence that the expression of a…
Effects of different kinds of essentiality on sequence evolution of human testis proteins
2016
We asked if essentiality for either fertility or viability differentially affects sequence evolution of human testis proteins. Based on murine knockout data, we classified a set of 965 proteins expressed in human seminiferous tubules into three categories: proteins essential for prepubertal survival (“lethality proteins”), associated with male sub- or infertility (“male sub-/infertility proteins”), and nonessential proteins. In our testis protein dataset, lethality genes evolved significantly slower than nonessential and male sub-/infertility genes, which is in line with other authors’ findings. Using tissue specificity, connectivity in the protein-protein interaction (PPI) network, and mul…
Angiogenesis and vascular network of teratocarcinoma from embryonic stem cell transplant into seminiferous tubules
2009
Background: Carcinoma in situ (CIS) of the testis is considered to be a precancerous germinal cell lesion, but the precise cellular and molecular mechanisms underlying transformation of CIS into invasive pluripotent cancer cells remain to be elucidated. Moreover, a satisfactory animal model for the experimental study of germinal tumours has not been developed to date. METHODS: We have developed a tumour model that involves the microinjection of green fluorescent protein-labelled embryonic stem (ES) cells (which are functionally equivalent to CIS cells) into syngenic mouse seminiferous tubules, a unique cell microenvironment in which germinal cells mature and CIS arise. To characterise the v…
Ultrastructural changes of the intercellular relationship in impaired human spermatogenesis
1980
In seven hypo- or aspermic patients, electron microscopic investigations of the intercellular connections of the seminiferous tubule were performed. The analysis of cell junctions of Sertoli cells and germ cells revealed irregularities of the Sertoli-cell junctions, hypoplasias of occluding junctions, hypo- and hyperplasias of the Sertoli-spermatid cell junctions and abnormal formation of Sertoli cell junctions with early spermatids, spermatocytes, and spermatogonia. Gap junction-like cell membrane specializations were very rare. Intercellular cytoplasmic bridges of germ cells were always present together with these cells. One hypoplastic bridge connecting two spermatogonia was found. The r…
A comparison of the effects of bilateral efferent duct ligation and of partial epididymectomy on the testes of rats.
1990
Testis weight as a percentage of body weight did not change following bilateral ligation of the efferent ducts (EDL) close to the epididymis, whereas following removal of part of the epididymis between the site of ligation and a point close to the junction between the caput and corpus (PCE), testis weight first rose linearly until Day 4 and then showed an exponential decrease between Days 4 and 28. After EDL, the perimeter of the seminiferous tubules rose for the first 7 days and then remained elevated, whereas after PCE, there was a linear decrease between Days 4 and 28. Following EDL, the percentage of altered and degenerated tubular cross-sections rose to about 30% and 10%, respectively,…