objective: mitochondria is a critical organelle within the cell and has important role in the oocyte development, thus the aim of this study was the comparison of mitochondrial distribution within the mouse oocyte at germinal vesicle (gv), germinal vesicle breakdown (gvbd) and metaphase ii (mii) stages using laser confocal microscopy (lscm). materials and methods: after superovulation of adult...

the changes of total calcium content of persian sturgeon, acipenser persicus follicles were investigated during different stages of germinal vesicle migration. total calcium content increased during maturation and ripening of the oocytes i.e. migration of nucleus toward the animal pole. according to data, the total calcium of follicles with polarization index (pi: the ratio of the distance of t...

background: cryopreservation and in vitro maturation (ivm) of oocyte is becoming an important technique in infertility treatment and fertility preservation. also it has been proposed to establish a genetic resource bank for endangered or commercially important animal species. objective: the aim of this study was to evaluate viability, maturation and fertilization rate of mouse immature oocytes ...

background: routine oocytes cryopreservation remained an elusive technique in the wide ranges of available assisted reproductive technologies. the microtubules of oocytes are vulnerable to cryoprotectants and thermal change during cryopreservation. objective: the effects of a vitrification protocol were investigated on the spindle and chromosome configurations of mice oocytes cryopreserved at t...

objectives: it was aimed to investigate the effects of different doses of follicle stimulating hormone (fsh) and activin a on the growth and maturation of preantral mouse follicles during the in vitro culture. methods: preantral follicles (90-100 µm in diameter) were harvested from 6-8 week-old syrian mice and cultured in tcm199 culture medium for 6 days to see the effect of fsh and activin a. ...

Background: Cryopreservation of oocytes, which is an interesting procedure to conserve female gametes, is an essential part of reproductive biotechnology. The objective of the present study was to investigate the effects of cumulus cells on survival,in vitro maturation,fertilization and subsequent developmental capacity of mouse germinal vesicle stage oocytes during vitrification. Materials and...

Cytoplasmic extracts of meiotically mature mouse oocytes were injected into immature Xenopus laevis oocytes, which underwent germinal vesicle breakdown within 2 h. Germinal vesicle breakdown was not inhibited by incubation of the Xenopus oocytes in cycloheximide (20 micrograms/ml). Identically prepared extracts of meiotically immature mouse oocytes, arrested at the germinal vesicle stage by dib...

developing a culture system for preantral follicles has important biotechnological implications due to the potential to produce a large number of oocytes for embryo production and transfer. to accomplish this goal, the present study was aimed to culture preantral follicles in the presence of different media, sera and fsh concentrations. six-week-old preantral follicles (95 ± 5 µm) were cultured...

Various stages of immature human oocytes were imaged for microtubule, microfilament and chromatin organization. After germinal vesicle breakdown, a small microtubule aster was observed near the condensed chromatin. The asters appeared to elongate and encompass the condensed chromatin. At metaphase I stage, microtubules were detected in the meiotic spindle. The meiotic spindle in metaphase II wa...

Meiotic reinitiation of the mouse oocyte is characterized by a slow entry into metaphase I, beginning with germinal vesicle breakdown and ending with spindle formation. It is accompanied by a cascade of protein kinases and phosphatases increasing protein phosphorylation. The activation of histone H1 kinase and that of the mitogen-activated protein kinase p42 have been compared during spontaneou...