[Method of dissecting of ovarian bursal membranes using a bipolar coagulator in mice and rats].

Ovarian bursal membranes were dissected using a bipolar coagulator during embryo transfer to the oviducts of pseudopregnant female mice and rats. The bipolar coagulator allowed accurate, fine coagulation of small vessels and wide dissection of ovarian bursal membranes without damage to the oviducts or ovaries.

Cryopreservation of unfertilized mouse oocytes from inbred strains by ultrarapid freezing.

Unfertilized mouse oocytes from inbred strains (BALB/c, C3H/He and C57BL/6) were frozen ultrarapidly by direct plunging into liquid nitrogen, immediately after exposure to a highly-concentrated solution (DAP 213: 2 M dimethyl sulphoxide, 1 M acetamide, and 3 M propylene glycol in PB 1), and were later thawed in a 37 degrees C waterbath. After thawing, 76.8-90.

[Cryopreservation of mouse strains by ultrarapid freezing].

Two-cell mouse embryos from four different inbred strains (BALB/c, C3H/He, C57BL/6 and DBA/2) and one closed colony (Slc:ICR) were frozen by direct placement into liquid nitrogen after a 10-15 sec exposure to a highly concentrated solution (DAP 213: 2 M dimethyl sulphoxide, 1 M acetamide, 3 M propylene glycol in PB 1), and later thawed in a 37 degrees C waterbath. The percentages of morphologically normal embryos were 80.7-92.

High survival rate of unfertilized mouse oocytes after vitrification.

Unfertilized mouse oocytes were cooled rapidly by directly plunging them into liquid nitrogen, immediately after exposure to a highly concentrated solution (modified VS1: 2.53 M-dimethyl sulphoxide, 2.36 M-acetamide, 1.

The morphogenesis of hindbrain crowding associated with lumbosacral myeloschisis.

The teratogenicity of ethylenethiourea (ETU) was investigated in Sprague-Dawley rats and Landrace pigs. Pregnant rats each received a single intragastric dose of ETU on a given day from day 8 to day 19 of gestation, and pregnant pigs were given a single dose of ETU from day 15 to day 19. Control animals received an ETU-free vehicle.

[Survival of 4-cell mouse embryos derived from in vitro fertilization after ultrarapid freezing and thawing].

Four-cell mouse embryos obtained by fertilization in vitro were frozen ultrarapidly, immediately after one-step exposure to a highly concentrated solution (modified VS1) at room temperature, and later thawed in a 37 degrees C waterbath. The proportion of morphologically normal embryos on thawing was 95.7% (198/207), and 83.

[Development of gamete intrafallopian transfer with preincubated preovulatory oocytes (new GIFT) and analysis of clinical data].

We developed a new treatment, Gamete Intrafallopian Transfer with the preincubated oocyte (New GIFT) and applied this method to all kinds of infertility where the patient had at least one tube. We performed 114 New GIFTs and dealt with the factors which influenced the establishment of pregnancy. 1.

[Experimental production of myeloschisis associated with hindbrain crowding in the central nervous system of rat fetuses by a single intragastric administration of ethylenethiourea].

66 pregnant rats were divided into 9 groups according to gestation day 11 to 19. These pregnant rats were subjected to a single intragastric administration of ethylenethiourea (ETU) and cesarian sectioned on day 20. No dam died following the ETU treatment, but the rate of fetal death was as high as 21.

Transplacental induction of myeloschisis associated with hindbrain crowding and other malformations in the central nervous system in Long-Evans rats.

Nine groups of 66 pregnant rats, grouped by gestation days 11 to 19, were subjected to a single, intragastric administration of ethylenethiourea (ETU). Cesarean section was performed on gestation day 20. No dam died following the ETU treatment, although a mortality as high as 21.