OBJECTIVE To examine whether the results of assisted reproduction with the use of elongated spermatids from a man with incomplete arrest of spermiogenesis and a high frequency of apoptosis among postmeiotic germ cells can be improved by germ cell in vitro culture. DESIGN Case report. SETTING Private assisted reproduction centers and a university department. PATIENT(S) Man with incomplete ...

Expression of the DMP1 transcription factor, a cyclin D-binding Myb-like protein, induces growth arrest in mouse embryo fibroblast strains but is devoid of antiproliferative activity in primary diploid fibroblasts that lack the ARF tumor suppressor gene. DMP1 binds to a single canonical recognition site in the ARF promoter to activate gene expression, and in turn, p19(ARF) synthesis causes p53-...

In last few hours of maturation, the mouse oocyte takes up over twenty billion zinc atoms and arrests after the first meiotic division, until fertilization or pharmacological intervention stimulates cell cycle progression toward a new embryo. Using chemical and physical probes, we show that fertilization of the mature, zinc-enriched egg triggers the ejection of zinc into the extracellular milie...

Preimplantation human embryos are characterized by various degrees of cytoplasmic fragmentation, and a high incidence of developmental arrest before the blastocyst stage. This review examines the current morphological and biochemical evidence that apoptosis plays a role in early human development and embryonic loss. Embryos examined 24 h or more after arrest often show characteristic features o...

We describe the effects of mutations in the fizzy gene of Drosophila melanogaster and show that fizzy mutations cause cells in mitosis to arrest at metaphase. We show that maternally supplied fizzy activity is required for normal nuclear division in the preblastoderm embryo and, during later embryogenesis, that zygotic fizzy activity is required for the development of the ventrally derived epid...

background: it has been demonstrated that performing a mock embryo transfer (et) significantly improves the pregnancy rate in ivf cycles. the mock et could be performed prior to the stimulation cycle or immediately before real et. the problem of the first procedure is the possibility of variation in the uterine position and or cervico�uterine angle. objective: the purpose of this study was to d...

background: natural endometrium in frozen-thawed embryo transfer (fet) may have some benefits upon implantation in patients with repeated implantation failure (rif). it might be due to possible differences between natural and stimulated endometrial growth factors and cytokins secretions. objective: the objective of this study was to compare the pregnancy rate of fet on modified natural cycle ve...

n meiosis II, vertebrate oocytes undergo a cell cycle arrest that is maintained until fertilization, but it has been difficult to identify the factors responsible for this process. By screening a novel cDNA library, Lefebvre et al., page 603, have discovered and characterized a protein that specifically regulates meiosis II spindle integrity during arrest. The work helps to explain how the cell...

n meiosis II, vertebrate oocytes undergo a cell cycle arrest that is maintained until fertilization, but it has been difficult to identify the factors responsible for this process. By screening a novel cDNA library, Lefebvre et al., page 603, have discovered and characterized a protein that specifically regulates meiosis II spindle integrity during arrest. The work helps to explain how the cell...

We identified a new gene that is interrupted by T-DNA in an Arabidopsis embryo mutant called raspberry3. raspberry3 has "raspberry-like" cellular protuberances with an enlarged suspensor characteristic of other raspberry embryo mutants, and is arrested morphologically at the globular stage of embryo development. The predicted RASPBERRY3 protein has domains found in proteins present in prokaryot...