Blood
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Spur cell anemia is a hemolytic anemia seen in severe alcoholic cirrhosis that is characterized by unusual morphology and a decreased ratio of phospholipids to cholesterol in the erythrocyte membrane. We hypothesized that defective phospholipid repair may contribute to the red blood cell (RBC) phospholipid abnormalities of spur cell anemia. Therefore, we compared RBCs from normal control subjects with RBCs from spur cell anemia patients. ⋯ However, more arachidonate was incorporated into the acyl-Cn of spur cells (spur cell acyl-Cn [24.5% +/- 2.9%] v normal control acyl-Cn [10.1% +/- 1.9%]; P = .0018). We conclude that phospholipid biosynthesis is inhibited and that acyl-Cn formation is spared in spur cell anemia RBCs. These metabolic changes may help account for the lipid abnormalities seen in spur cell anemia RBCs and contribute to the hemolytic process.
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The acute chest syndrome (ACS), a pneumonia-like illness in sickle cell patients, is one of the most frequent causes of their morbidity and hospitalizations. Repeated ACS events may predict the development of chronic lung disease. ACS is reported as a frequent cause of death in these patients. ⋯ In multivariate analysis, other factors affecting incidence in SS patients were degree of anemia (lower ACS rates in patients with lower steady-state Hb levels) and fetal Hb (lower rates in patients with high fetal Hb). There was also a positive association between ACS rate and steady-state leukocyte count. The relationship of ACS rate to higher steady-state Hb levels in SS patients is unexplained but might be caused by increased blood viscosity.
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The effects of neutrophil cathepsin G on the glycoprotein (GP) Ib-IX complex of washed platelets were examined. Cathepsin G resulted in a concentration- and time-dependent decrease in the platelet surface GPIb-IX complex, as determined by flow cytometry, binding of exogenous von Willebrand factor (vWF) in the presence of ristocetin, and ristocetin-induced platelet agglutination. Cathepsin G resulted in proteolysis of the vWF binding site on GPIb alpha (defined by monoclonal antibody [MoAb] 6D1), as determined by increased supernatant glycocalicin fragment (a proteolytic product of GPIb alpha); decreased total platelet content of GPIb; and lack of effect of either cytochalasin B (an inhibitor of actin polymerization), prostaglandin I2 (an inhibitor of platelet activation), or prior fixation of the platelets. ⋯ Experiments with Serratia protease-treated and Bernard-Soulier platelets showed that neither platelet surface GPIb nor cathepsin G-induced proteolysis of GPIb were required for the cathepsin G-induced redistribution of the remnant of the GPIb-IX complex or the cathepsin G-induced increase in platelet surface P-selectin. In summary, neutrophil cathepsin G modulates the platelet surface expression of the GPIb-IX complex both by proteolysis of the vWF binding site on GPIb alpha and by a cytoskeletal-mediated redistribution of the remainder of the complex. Prior studies show that, although thrombospondin 1, antiserine proteases, and plasma are all inhibitors of cathepsin G, the effects of cathepsin G on platelets, including an increase in surface GPIIb-IIIa, occur during close contact between neutrophils and platelets in a protective microenvironment (eg, thrombosis and local inflammation).(ABSTRACT TRUNCATED AT 400 WORDS)
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We had reported previously (Blood 81:1880, 1993) that allogeneic blood transfusions (ABT) administered before the infusion of tumor cells in both inbred and outbred experimental animals promote tumor growth and that this effect can be ameliorated by leukodepletion. To better reproduce the human situation, we evaluated, in this present study, the effect of ABT in animals with established tumors using enumeration of pulmonary metastatic nodules as the end point. The role of allogeneic blood component transfusions in promoting tumor growth and the relative efficacy of prestorage versus poststorage leukodepletion of the ABT in preventing tumor growth enhancement were also evaluated. ⋯ Significantly lower numbers of pulmonary nodules were observed in rabbits that received prestorage LD-ABT compared to animals transfused with poststorage LD-ABT, but no significant difference was seen in rabbits that received poststorage LD-ABT compared with animals transfused with nonleukodepleted ABT. These studies show that ABT promote tumor growth of established animal tumors, that the ABT-induced tumor growth effect is related to the presence of donor allogeneic leukocytes, and that this effect can be ameliorated by prestorage leukodepletion. The present results also provide evidence for the lack of efficacy of poststorage leukodepletion in preventing ABT tumor growth promotion.(ABSTRACT TRUNCATED AT 400 WORDS)