background: over recent decades a possible decrease in sperm quality and an increase in the incidence of testicular cancer have been reported in many populations. some recent findings, as cohort studies, showed an increased risk of testicular cancer in men with abnormal semen analysis. case: a 30 years old man referred to our clinic with chief compliant of infertility for 3 years. spermogram re...

a key factor in spermatogenesis and disorders associated with this protein have been recognized to be related to male infertility. although it was suggested that this protein could have different functions during germ cell development, no studies have been conducted to uncover the mechanism of this potential function yet. here, we analyzed the expression pattern of rbmy protein isoforms in test...

Embryos of many animal models express germ line determinants that suppress transcription and mediate early germ line commitment, which occurs before the somatic cell lineages are established. However, not all animals segregate their germ line in this manner. The ‘last cell standing’ model describes primordial germ cell (PGC) development in axolotls, in which PGCs are maintained by an extracellu...

Nanos (Nos) is one of the evolutionarily conserved proteins known to direct germ-line development. In Drosophila, maternal Nos protein maintains transcriptional quiescence in the germ-line progenitors or pole cells to repress ectopic expression of somatic genes. Here we show that maternal Nos is required to establish and maintain germ-line identity by preventing apoptosis and somatic cell fate....

background: creation of artificial gametes may provide a universal solution for these patients of lacking gametes. stem cell technology may provide a way to obtain fully functional gametes. retinoic acid (ra) can initiate meiosis. several studies have demonstrated that ra can promote sperm cells differentiation from mouse embryonic stem cells (mescs) and other cells from human embryonic stem ce...

background and objective: germ cell tumor (gct) accounts for approximately 2-3% of all malignancies in children. in this respect, about 20% of patients with gct are still resistant to therapy. materials and methods: the cross-sectional strategy of this survey was undertaken on 57 patients with germ cell tumor who admitted to ali asghar children hospital during the years 1990- 2003. in this stud...

Formation of motile sperm in Drosophila melanogaster requires the coordination of processes such as stem cell division, mitotic and meiotic control and structural reorganization of a cell. Proper execution of spermatogenesis entails the differentiation of cells derived from two distinct embryonic lineages, the germ line and the somatic mesoderm. Through an analysis of homozygous viable and fert...

objective(s):mesenchymal stem cells (mscs) derived from wharton’s jelly (wj-mscs) are now much more appealing for cell-based infertility therapy. hence, wj-mscs differentiation toward germ layer cells for cell therapy purposes is currently under intensive study. materials and methods: mscs were isolated from human wharton’s jelly and treated with bmp4, retinoic acid (ra) or co-cultured on human...

Gap junctions coordinate processes ranging from muscle contraction to ovarian follicle development. Here we show that the gap junction protein Zero population growth (Zpg) is required for germ cell differentiation in the Drosophila ovary. In the absence of Zpg the stem cell daughter destined to differentiate dies. The zpg phenotype is novel, and we used this phenotype to genetically dissect the...