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...

In many animals, oocytes enter meiosis early in their development but arrest in meiotic prophase I. Oocyte growth, which occurs during this arrest period, enables the acquisition of meiotic competence and the capacity to produce healthy progeny. Meiotic resumption, or meiotic maturation, involves the transition to metaphase I (M phase) and is regulated by intercellular signaling and cyclin-depe...

We evaluated the involvement of cyclic adenosine monophosphate-response element (CRE)-dependent transcriptions in all-trans retinoic acid (ATRA)-induced myeloid differentiation using human monoblastic U937 cells. ATRA treatment caused an increment in the CRE-dependent transcription activity and induced a wide variety of differentiation phenotypes including functional and morphological maturatio...

OBJECTIVE To investigate the effect of a phosphodiesterase type 3 inhibitor in oocyte maturation medium on subsequent embryo development. DESIGN Animal study. SETTING University laboratory. ANIMAL(S) CD-1 mice. INTERVENTION(S) Immature oocytes were arrested meiotically in medium containing a specific phosphodiesterase type 3 inhibitor, cilostamide (1 micromol/L, 5 micromol/L, and 10 mic...

In an attempt to determine whether co-culture could promote sperm maturation, three patients with non-obstructive azoospermia, two with maturation arrest at the level of primary spermatocytes and one patient with <1% tubules showing complete spermatogenesis, and one patient with total globozoospermia, gave consent to experimentally co-culture round spermatids retrieved from the testicle on Vero...

Microinjection is established as the method of choice in the treatment of severe male factor infertility as well as in azoospermic patients. Recent studies have shown that fertilization and cleavage can be achieved by injection of ejaculated as well as testicular elongated spermatids into oocytes. Here we report on the two first pregnancies worldwide resulting from elongated spermatid injection...

To evaluate the diagnostic efficacy of needle aspiration biopsy of seminiferous tubules (NABST) and to represent the redistributed diagnostic results corresponding to testicular volumes and follicle-stimulating hormone (FSH) levels. In this retrospective study, we investigated 65 infertile men with either azoospermia or oligoasthenoteratozoospermia. Following NABST, specimens were stained with ...

The arrest of meiotic prophase in mammalian oocytes within fully grown follicles is dependent on cyclic adenosine monophosphate (cAMP) regulation. A large part of cAMP is produced by the Gs-linked G-protein-coupled receptor (GPR) pathway. In the present study, we examined whether GPR3 is involved in the maintenance of meiotic arrest in porcine oocytes. Expression and distribution of GPR3 were e...