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.

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