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...

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...

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. ...

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...

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...

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: in vitro maturation (ivm) of oocytes is a promising technique to reduce the costs and avert the side-effects of gonadotropin stimulation for in vitro fertilization (ivf). the pregnancy rates from oocytes matured in vitro are much lower than those of in vivo stimulation cycles, indicating that optimization of ivm remains a challenge. objective: in this study, we investigated the effe...

The present paper shows through conventional light microscopy, silver nitrate impregnation and Transmission Electron Microscopy, the changes in nuclear activity that occurs in the ovary cells during vitellogenesis of Apis mellifera (Linnaeus, 1758). The material impregnated by silver nitrate was detected in nurse cells, oocyte germinal vesicle and follicular cells, whose amounts are greater in ...