Patchwork. a minor change could allow chilled platelets to keep the coagulation once transfused.
the fight against a problem that hematologists and blood banks it has long abandoned it, a team of scientists has determined how to store platelets in the refrigerator instead of the temperature ambient. If maintained in other experiments, the technique could stabilize supply of platelets and reduce the risk of bacterial infections transfusions.
Platelets are disk-shaped cells that help blood clot. Every year millions of units transfused in people around the world to stem the bleeding. But because platelets must be stored at warm temperatures, they last only five days after donation. (In contrast, the red cells can be refrigerated for more than a month, and plasma may be frozen for a year). They can also host bacteria that are a major cause of the original infection through transfusion. In January, scientists at Harvard Thomas Stossel, Karin Hoffmeister, and their colleagues found that when platelets are cooled, some protein receptors on their surfaces stick together, revealing a sugar molecule. This triggers a response in the liver. When platelets are infused, liver cells yank them out of circulation
Now, the team of Hoffmeister found a potential cure, as reported in this week's issue of science . Other experiments in test tubes showed any part of the liver cells sugar molecule were noticed. Scientists reasoned that if they threw a coat over sugar - in the form of another type of sugar molecule with a different chemistry, which covers the first - the liver does not recognize the pads, and they circulate freely.
Hoffmeister and his colleagues extracted the mouse blood platelets mixed with a solution containing the second and sugar concoction refrigerated for 2 hours. They then injected platelets modified into mice, and the cells appeared not the worse for wear. The group also studied human platelets with a similar sweet disguise. After cooling platelets up to 12 days and examine them in a petri dish and then, the team Stossel found that function seemed intact.
The technique "seems to offer real promise" not only to reduce pathogens, but also to extend the storage time, said Roger Dodd, executive director of biomedical safety for the American Red Cross in Rockville ., Maryland After more expansive tests, modified cold rooms can allow blood banks - and beneficiaries - to start counting their savings
Related Sites
of Thomas Stossel laboratory
the American Association. of blood banks
__gVirt_NP_NN_NNPS <__ Backgrounder on the blood, PBS
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