Biomedical subjects

Yoshihiro Hirose

Publications and source records attributed to Yoshihiro Hirose.

4 recordsLinked to original sources

PubMed2005

Buffalo rat liver cells produce factors that support preimplantation development of mouse embryos cultured in vitro.

To examine the effects of buffalo rat liver (BRL) cells on the preimplantation development of mouse embryos in vitro, we first cultured two-cell mouse embryos alone in serum-free Dulbecco modified Eagle medium. As expected, the embryos did not develop to subsequent stages. However, when cocultured with BRL cells, the embryos developed to the blastocyst stage efficiently. Direct contact of embryos with BRL cells was not necessary for development: the medium conditioned by BRL cells contained soluble factors that supported the preimplantation development of mouse embryos. Embryos cultured with BRL-conditioned medium that was replaced at various intervals had a further increased rate of development to the blastocyst stage. This finding indicated that the activities of the factors were maintained only briefly. Seven proteins between 35 and 44 kDa that were detected in the medium were highly beneficial to the development of the embryos. Follistatin-related protein and pigment epithelium-derived factor are believed to be the factors supporting embryo development. The other five proteins also may improve the environment for the development of mouse embryos cultured in vitro.

Amino Acid Sequence↗

PubMed2004

Zona-float method for separating mouse eggs from other cells.

We have developed a new method for separating mouse eggs from other cells, such as cumulus cells, using centrifugation with Percoll. Solutions of 45, 22.5, 11.3, and 5.6% Percoll were tested. With the 22.5% solution, 99% of whole eggs obtained by in vitro fertilization were collected from the upper part of the Percoll solution, and 98% of 2-cell embryos collected from these eggs developed to the blastocyst stage. Offspring were obtained after transfer of collected embryos to female mice. The greatest advantage of this method is that undamaged eggs are separated from other cells in one simple operation, regardless of the number of eggs.

Animals↗

PubMed2003

Pregnancy by the tubal transfer of embryos developed after injection of round spermatids into oocyte cytoplasm of the cynomolgus monkey (Macaca fascicularis).

BACKGROUND: Round spermatids have been used as substitute gametes in basic reproductive research and in infertility clinics. In humans, however, the efficiency of fertilization and pregnancy is generally much lower after round spermatid injection (ROSI) than after injection with mature sperm. We examined the ability of round spermatids to support embryonic development using a non-human primate as a model. We chose cynomolgus monkeys because, as in humans, their round spermatids have the oocyte-activating capacity of mature sperm. METHODS: We examined fertilization and subsequent development of embryos after ROSI and then transferred the embryos into the oviducts of female monkeys. RESULTS: Seventy-seven per cent of survived oocytes were activated and had formed pronuclei or the second polar body; 79% of the oocytes cultured developed to the 2-cell stage, and 23% developed to the blastocyst stage. Ultrasonography showed a normal-sized fetus in the uterus of a recipient, but the fetus spontaneously aborted at day 103. CONCLUSIONS: The round spermatids of cynomolgus monkeys can be used as substitute gametes to support embryonic development at least to mid-gestation. This non-human primate is a suitable animal model for round spermatid conception in mammals, especially humans, and for biological and genetic characterization of events following ROSI.

Animals↗

PubMed2003

Aspiration method to collect epithelial cells from mouse, rat, and monkey oviducts.

When oviduct epithelial cells are collected by using enzymatic methods that involve protease such as trypsin, other cells unintentionally are collected as well, especially from small laboratory animals such as mice and rats, thus contaminating the collected sample. We therefore developed a simple nonenzymatic method that involves using a glass micropipette to aspirate the oviduct epithelial cells from the oviduct. This aspiration method easily removed oviduct epithelial cells from mice, rats, and cynomolgus monkeys. Culture of the collected oviduct epithelial cells confirmed that the cells could adhere and grow on a petri dish. Although this aspiration technique was developed for use in small animals, our results show that it can be applied to cynomolgus monkeys. The advantages of this technique are its simplicity and its success in collecting oviduct epithelial cells from oviducts.

Animals↗