Transfusion
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The cardiovascular response to acute isovolemic anemia in humans is thought to differ from that of other species. Studies of anesthetized humans have found either no change or a decreased heart rate. A previous study showed that in 32 healthy unmedicated humans, heart rate increased during acute isovolemic anemia. The hypothesis that heart rate in humans increases in response to acute isovolemic anemia and that the increase is affected by gender was tested. ⋯ In 95 unmedicated, healthy humans, heart rate was a linear function of Hb during acute isovolemic anemia. Females had a significantly greater slope of increase in heart rate with decreasing Hb concentration than did males. The relationship is consistent among individuals, is similar to that reported for conscious dogs, and differs from that found previously in anesthetized humans.
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TRALI is thought to be triggered by recipient-specific anti-HLA class I or antibodies against neutrophils in donor plasma. Recently, anti-HLA class II have also been implicated. The prevalence of anti-HLA class II was investigated in normal volunteer platelet donors and in two nonfatal TRALI cases utilizing a flow-based assay. Potential target antigens also were investigated. ⋯ FlowPRA assays often detect anti-HLA class I not detected by conventional lymphocytotoxicity assays. These assays reveal anti-HLA class II in normal female donor plasma and in sera implicated in TRALI. Immunohistochemical studies failed to reveal endothelial or intravascular-WBC HLA class II antigen expression in lung tissue derived from TRALI cases or controls, but demonstrated HLA class II expression on pulmonary macrophages.