X-Message-Number: 12571 Date: Fri, 15 Oct 1999 11:00:52 -0700 (PDT) From: Doug Skrecky <> Subject: best survival for embryos with ethylene glycol Authors Mukaida T. Wada S. Takahashi K. Pedro PB. An TZ. Kasai M. Institution Hiroshima HART Clinic, Japan. Title Vitrification of human embryos based on the assessment of suitable conditions for 8-cell mouse embryos. Source Human Reproduction. 13(1O):2874-9, 1998 Oct. Abstract Experiments were conducted to find a suitable cryoprotectant and suitable procedure for vitrification of 8-cell mouse embryos. The method was then applied clinically to the cryopreservation of human embryos in our assisted reproduction programme. Mouse embryos were vitrified with 30 or 40% 1,2-propanediol (PROH), dimethylsulphoxide (DMSO), ethylene glycol, glycerol, or acetamide, each diluted with a solution containing 30% Ficoll plus 0.5 M sucrose. Embryos were exposed to the solutions for 0.5 or 2 min at 20 or 25 degrees C, cooled in liquid nitrogen and warmed rapidly. Embryo survival was assessed by in-vitro development. In PROH-, DMSO- and acetamide-based solutions, higher survival rates (29-82%) were obtained with less permeating conditions, suggesting that these cryoprotectants are considerably toxic. In glycerol- and ethylene glycol-based solutions, however, higher survival rates (74 and 92% respectively) were obtained with more permeating conditions, suggesting that these cryoprotectants are less toxic. Human embryos on days 2-3 were vitrified in an ethylene glycol-based solution (EFS40). Survival, assessed by the morphology, was higher in 4-cell embryos on day 2 and 8-cell embryos on day 3 than in 2-3-cell embryos on day 2 or 2-7-cell embryos on day 3. From 18 transfers, one ended with the delivery of healthy twin babies. Additional note by poster: Osmotic toxicity with glycerol is very hard to avoid, due to the slow permeation of this sugar alcohol through cell membranes. This disadvantage does not apply to ethylene glycol. The goal of cryonics is the revival of frozen humans. Here this is acheived, albet only with human embryos. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=12571