New Technique Devised For Human Stem Cells
Scientists in Massachusetts reported yesterday that they have developed a new means of growing human embryonic stem cells, the versatile cells that show promise as treatments for various diseases.
In a research report appearing in the online version of the medical journal the Lancet, Irina Klimanskaya and Robert Lanza of Advanced Cell Technology in Worcester said they had grown the cells without their ever coming in contact with animal cells. Until now, researchers have relied on mouse cells to provide key nutrients for cultured human embryonic stem cells. That has led to concerns that the human cells might become infected with mouse viruses and be unusable medically.
Other scientists noted that the new technique still relies on proteins and other ingredients derived from animal cells. So although the new culture system probably minimizes the chances of the stem cells' becoming infected with animal viruses, it does not eliminate the possibility of those cells picking up animal proteins, which may still be problematic.
Other scientists, including some at Geron Corp. in Menlo Park, Calif., have reported they are developing a system for growing embryonic stem cells with no animal products.
Milk's Benefit to Kids' Bones Questioned
Children who drink more milk do not necessarily develop healthier bones, researchers said yesterday in a report that stresses exercise and consumption of calcium-rich foods such as tofu and broccoli.
The report in the journal Pediatrics drew its conclusions from previously published studies and was written by researchers from the Physicians Committee for Responsible Medicine, which advocates a strict vegetarian diet.
"This analysis of 58 published studies shows that the evidence on which U.S. dairy intake recommendations are based is scant," study author Amy Lanou said in a statement.
The government has gradually increased guidelines for daily calcium intake, largely from dairy products, to between 800 and 1,300 milligrams to promote healthy bones and prevent osteoporosis.
Data was scarce on the effect of calcium intake for children younger than 7, the report said.
Doctors Urged to Heed Mini-Strokes' Warning
People often suffer mini-strokes days before a major stroke and should seek help within hours to get the most effective treatment, British researchers said.
The study, published in the journal Neurology, suggests doctors should act more quickly in investigating symptoms of a mini-stroke, which can be vague. Known as transient ischemic attacks (TIAs), mini-strokes, like major strokes, have symptoms such as nausea, a sudden loss of balance or consciousness, and vision disturbances. But the symptoms last just a few minutes.
"This study indicates that the timing of a TIA is critical, and the most effective treatments should be initiated within hours of a TIA in order to prevent a major attack," said Peter Rothwell, a neurologist at Radcliffe Infirmary in Oxford, England.
-- From News Services
and Staff Reports