In their studies, the scientists tested the responses of the circulatory systems of human subject in specialized chambers where the scientists could control atmospheric pressure and gas concentrations. The scientists raised or lowered oxygen levels in the chambers and analyzed the response of the subjects' blood cells. From such analyses, the scientists demonstrated that nitric oxide in the blood cells is an active regulatory molecule that causes the oxygen-carrying hemoglobin molecules in red blood cells to undergo subtle shape changes in response to varying concentrations of oxygen in tissues. Nitric oxide works by relaxing or contracting blood vessels.
The researchers are publishing their findings in the July 2002 edition of Nature Medicine, which posted the study as an advance online publication today (June 3, 2002) at http://www.nature.com/cgi-taf/dynapage.taf?file=/nm/journal/vaop/ncurrent/index.html.
The scientists said that their discoveries help explain why some treatments -- such as blood transfusions or drugs like erythropoietin that boost red blood cell production -- either don't work, or even lead to death. The findings could also explain why there is a direct relationship between high red blood cell counts and stroke, heart attack and hypertension, said the scientists. Additionally, the findings could offer new avenues of research in treatin
Contact: Richard Merritt
Duke University Medical Center