| On Aug. 9, 2001, President Bush said the federal government would not fund any research that used batches of embryonic stem cells created after that date, saying the government should not be encouraging the destruction of human embryos. The experiments announced yesterday were aimed at finding a way around this restriction, which scientists say has been holding back stem cell research in this country. |
| The scientists at Advanced Cell Technology, led by Dr. Robert Lanza, sought to show they could create embryonic stem cells without harming the embryo. They built on a technique that is commonly used to test embryos for genetic abnormalities at fertility clinics. In this technique, called pre- implantation genetic diagnosis, or PGD, a technician delicately removes a single cell from an eight-celled embryo. If the cell is genetically normal, then the embryo is placed in the mother. The procedure does not appear to harm the embryo, according to the paper in Nature. |
| Lanza's team, working with mice embryos, showed that this single cell can be used to make embryonic stem cells. In an interview, Lanza suggested that a fertility clinic doing PGD could remove a single cell, as it normally does, but then allow it to divide once in a dish. One cell could be used for the genetic testing, and the other could be used to make stem cells. |
| But scientists and ethicists identified several potential problems with the approach. Pacholczyk said Catholic teaching does not approve of PGD, because it is a violation of the embryo and is not aimed at helping the embryo. It is also possible that the removed cell has the potential to become an embryo, meaning that its destruction would also be viewed as taking a human life. |
| There are also practical problems, according to Douglas Powers, chief scientific officer of Boston IVF, a fertility clinic. For example, he said, there is the chance that the removed cell could die in its dish -- meaning it could not be tested for genetic abnormalities -- while scientists were waiting for it to divide. This could interfere with the patient's care, and perhaps mean that she would have to delay her attempt to become pregnant. |
| ''When you start mixing the obtaining of research material with a clinical test, you get into a very tricky area," Powers said. |
| The other research, conducted by Rudolf Jaenisch, a Whitehead scientist, and his graduate student Alexander Meissner, is a test of a concept proposed last year by Dr. William Hurlbut, a member of the President's Council on Bioethics who teaches ethics at Stanford University. The idea is to create a genetically modified egg cell that is able to create embryonic stem cells, but is not able to develop into an embryo. |
| The technique gets its name, ''altered nuclear transfer," from the fact that it is a variation on nuclear transfer, also known as cloning. In nuclear transfer, the nucleus of an adult cell, which contains its DNA, is placed into an egg cell that has had its own nucleus removed, and the new cell is prompted to grow. |
| This can grow into an embryo genetically similar to the adult who donated the original cell. With altered nuclear transfer, the aim is to alter the genes of the nucleus before they are placed into the egg cell, to ensure that it is unable to become an embryo. |
| In the experiment, which was done using mice, the team showed that when they prevent a particular gene from functioning, the egg cell can create embryonic stem cells but is unable to become a viable embryo. In the experiment, the cells appear to divide and develop normally for several days, but it is then unable to develop a crucial outer layer of cells that eventually becomes the placenta. |
| But Pacholczyk said he has reservations about the particular gene used because it seems that the procedure creates a ''crippled embryo" -- which he considers to be a life that is quickly extinguished -- instead of avoiding the creation of an embryo. |
| He said that he and others were more hopeful about a variant on the idea that targets different genes. This idea was proposed by Dr. Markus Grompe, who is director of the Oregon Stem Cell Center and a professor at the Oregon Health and Science University in Portland. |
| Grompe said that he plans on doing experiments to test the ideas using monkey embryos, but that he does not yet have funding for the work." |
| Gareth Cook can be reached at cook@globe.com. |
| Women's Thyroid Stem Cells eyed as alternative resource |
| by Michael Lasalandra (BOSTON HERALD - Dec. 14, 2001) |
| Boston - Researchers at New England Medical Center say they have found evidence of fetal stem cells |
| in the thyroids of adult women and say the findings could offer another source of the cells that may be able to be used as sources of replacement parts or new tissues. |
| "We want people to consider that in the stem cell debate there may be another interpretation," said |
| Dr. Diana Bianchi, chief of the NEMC/Floating Hospital department of genetics. |
| In 1996, researchers found fetal stem cells floating around in the blood of women who previously |
| had been pregnant. The cells were left over from their babies. |
| In a new paper, to be published tomorrow in the LANCET, Bianchi reported finding evidence of fetal stem cells in the thyroids of adult women who had once been pregnant. In 16 of the 29 women studied, fetal cells were found in the thyroid containing the Y chromosome, indicating they were from their |
| babies. In one of the women, researchers found fully differentiated male thyroid cells attached to the |
| rest of the thyroid. |
| In essence, "one part of her thyroid was male and one part was female," Bianchi said. |
| The finding could indicate that the stem cells made a new thyroid. |