Word: fetal
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Dates: during 1980-1989
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...Stanford scientists announced their findings, which involved transplanting human fetal tissue into the mice, just as a special advisory committee of the National Institutes of Health was meeting in Bethesda, Md., to consider the scientific and ethical issues surrounding the use of human fetal tissue in experimental research. The reason: to develop recommendations that may influence the Reagan Administration's proposed ban on such federally funded research...
...work with fetal tissue was by far the more elaborate of the two research efforts. Led by Stanford's Dr. Mike McCune and Irving Weissman, the scientific team actually reconstituted a human immune system in mice that lacked their own immune systems. Because of a genetic abnormality known as SCID (for severe combined immunodeficiency), these mice usually die at an early age, often of pneumocystis pneumonia, the disease that kills many AIDS patients. The researchers implanted some 300 of the defective mice with tissue taken from human fetal thymus, where certain immune and blood cells develop, and with blood-forming...
After more than a year, the Stanford mice are still thriving. Their new immune systems, however, must be sustained by injections of fetal liver cells every eight to twelve weeks. In addition, researchers are not sure whether all the parts of the human system are functioning in the mice. "We'll find that out," says Weissman, "but we'll have to do every known test for human immune cells. These mice open ways of studying human systems, normal or diseased, under experimental circumstances that were impossible before...
Because SCID mice lack immune systems, the scientists did not expect them to reject the transplanted human cells. Researchers also suspected that the human fetal cells, since they are too immature to distinguish themselves from foreign cells, would not reject the mice in a graft-vs.-host response. But, surprisingly, the adult human cells used in the La Jolla research did not reject the mice either. "That these human cells recirculate around in the mice without caring is astounding," said Dr. Donald Mosier, head of the La Jolla research team...
...premature -- a clearer picture of the effects of the drug on the fetus is emerging. It is not a pretty one. Because a mother's crack binge triggers spasms in the baby's blood vessels, the vital flow of oxygen and nutrients can be severely restricted for long periods. Fetal growth, including head and brain size, may be impaired, strokes and seizures may occur, and malformations of the kidneys, genitals, intestines and spinal cord may develop. If the cocaine dose is large enough, the blood supply can be cut so sharply that the placenta may tear loose from the uterus...