X-Message-Number: 18744 Subject: SF Gate: Big hurdles overcome in stem cell research From: "Peter Christiansen" <> Date: Sun, 10 Mar 2002 08:24 -0800 ---------------------------------------------------------------------- This article was sent to you by someone who found it on SF Gate. The original article can be found on SFGate.com here: http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2002/03/10/MN9865.DTL ---------------------------------------------------------------------- Sunday, March 10, 2002 (SF Chronicle) Big hurdles overcome in stem cell research Nicholas Wade, New York Times Scientists say they have jumped a double hurdle in the race to cure disease with embryonic stem cells, the all-purpose clay from which the body is sculptured. Working with mice, one team at the Whitehead Institute at the Massachusetts Institute of Technology has mastered making embryonic stem cells metamorphose into the cells that generate the blood and immune systems. Another team converted skin cells from the tip of a mouse's tail back into the embryonic state and then, with the first team's technique, used them to cure a mouse whose blood and immune system had been destroyed. The experiments were published electronically on Friday in the journal Cell. The second experiment is among the first claimed instances of therapeutic cloning, a technique strongly opposed by those who fear it may be used instead to clone a person. By providing proof of its possible benefits, the experiment "hopefully should influence the debate," said Dr. Rudolf Jaenisch of the institute in Cambridge, Mass. Therapeutic cloning is based on the idea of taking a mature cell, like a skin cell, from a patient, walking it back in biological time to its embryonic state, then growing new mature cells of the type necessary to repair a diseased organ. The controversy arises because the nucleus of the skin cell, containing the patient's genome or genetic information, would be injected into an unfertilized human egg whose own nucleus had been removed. The injected human egg would be kept in laboratory glassware and allowed to divide a few times into an early embryo, from which embryonic stem cells can be harvested. If the embryo were placed into a woman's uterus, it might successfully develop, creating a clone or almost identical twin of the patient who provided the skin cell nucleus. Jaenisch and his colleagues have created mouse embryos by this method and converted them into blood-forming stem cells, first correcting an inborn genetic defect of the donor mouse by a standard genetic method. The blood-forming cells were then injected back into the mice that donated the nuclei. These mice had been irradiated to destroy their bone marrow cells and would have died without the new cells. Jaenisch's team had to inject 202 unfertilized mouse egg cells with skin cell nuclei to get a single working embryo. Acquiring such a number of human egg cells would be difficult and expensive. ---------------------------------------------------------------------- Copyright 2002 SF Chronicle Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=18744