Gas therapy for sickle-cell anemia.Inhalation of nitric oxide nitric oxide or nitrogen monoxide, a colorless gas formed by the combustion of nitrogen and oxygen as given by the reaction: energy + N2 + O2 → 2NO; m.p. −163.6°C;; b.p. −151.8°C;. gas may reverse the defect behind sickle-cell anemia sickle-cell anemia Blood disorder (see hemoglobinopathy) seen mainly in persons of Sub-Saharan African ancestry and their descendants and in those from the Middle East, the Mediterranean area, and India. , according to a preliminary report. If nitric oxide's promise is confirmed, it would represent the first treatment to address the underlying flaw in this disorder, says C. Alvin Head of Harvard Medical School Harvard Medical School (HMS) is one of the graduate schools of Harvard University. It is a prestigious American medical school located in the Longwood Medical Area of the Mission Hill neighborhood of Boston, Massachusetts. in Boston. Sickle-cell anemia is caused by an abnormal form of hemoglobin, an oxygen-carrying molecule in the blood. The defective hemoglobin molecules stick together after releasing oxygen and form sickle shapes that clog the body's tiny blood vessels Blood vessels Tubular channels for blood transport, of which there are three principal types: arteries, capillaries, and veins. Only the larger arteries and veins in the body bear distinct names. . Such jams cause a painful, potentially life-threatening sickle-cell crisis. A 1977 report had suggested that nitric oxide alters the shape of hemoglobin. Head, Ricardo Martinez-Ruiz, and their colleagues wondered if this gas might help people afflicted af·flict tr.v. af·flict·ed, af·flict·ing, af·flicts To inflict grievous physical or mental suffering on. [Middle English afflighten, from afflight, with sickle-cell anemia. The researchers recruited nine people with the disease who were not having a sickle-cell crisis. They had the volunteers inhale a low dose of nitric oxide for 45 minutes. In eight of the volunteers, the experimental treatment increased hemoglobin's affinity for oxygen and thus prevented the molecule from assuming the abnormal shape. Other studies have suggested that such an effect would decrease the likelihood of a sickle-cell crisis. The inhalation of nitric oxide had no effect on hemoglobin in the blood of volunteers without sickle-cell disease. The researchers report their findings in the September Journal of Clinical Investigation The Journal of Clinical Investigation (JCI or J Clin Invest) is a leading biomedical journal, which is radically different from many of its peers in having a high impact factor (in 2006, 15.754) and offering all its contents entirely free. . Head and his colleagues are now beginning to examine whether the gas may help reverse a sickle-cell crisis. They are recruiting 60 volunteers for a study expected to yield results in a year. "Right now, there is no therapy for [sickle-cell] crisis," Head says, noting that patients generally receive only pain killers and other palliative treatments when they suffer an attack. Head suspects that nitric oxide, used on a regular basis, would ward off such episodes. He imagines patients someday using a gas inhaler inhaler /in·hal·er/ (in-hal´er) 1. an apparatus for administering vapor or volatilized medications by inhalation. 2. ventilator (2). in·hal·er n. much like an asthma inhaler to prevent their hemoglobin from getting into a traffic jam. |
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