title: Some problems on fertilization and embryonic development in vitro in mammals.
abstract: Recently, progress of studies and technique developments on human and mammalian fertilization and early embryonic development in vitro are markedly. At the present time, however, some problems are remaining. In mammalian embryo culture, the major obstacles to progress in analysing epigenic regulation of development in other than the mouse and rabbit are the infamous blocks to development in vitro. At the present time, further studies are needed to dissolve the precise mechanism of these blocks. Factors which affect on embryo development are a great number and analysis of them is considered to be important for clinical application of the embryo culture system. Intracytoplasmic sperm injection(ICSI), at the present time, is employed widely for basic research and the treatment of male infertility. Using ICSI, recent studies are showing that mouse round spermatids can fertilize mature oocyte and the fertilized oocytes(embryos) develop into normal offspring after embryo transfer to foster mothers. Also, a recent report indicates development of normal mice from oocytes injected with secondary spermacyte nuclei. However, since some unsolved problems on spermatogenic cells such as round spermatids and secondary spermacytes remain, further studies are needed.
authors.affiliation: Department of Animal Cell Biology, Nihon University College of Bioresource Sciences, Fujisawa, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sato
mesh_terms: D000818:Animals; D005314:Embryonic and Fetal Development; D005307:Fertilization in Vitro; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D011817:Rabbits