Blood
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The development of methods for storing platelet concentrates (PCs) at 22 degrees C for transfusion has been predominantly empiric, with minimal knowledge of metabolic events occurring during storage. It is known that a decrease in pH due to accelerated production of lactic acid in hypoxic conditions is a major cause for loss of platelet viability. In the current studies, we have measured metabolic parameters such as O2 and glucose consumption rates and CO2 and lactic acid production rates. ⋯ A further increase in lactate concentration from 25 mmol/L to 40 mmol/L correlated with a further fall in pH to 5.8. Thus, the ultimate storage life of a PC is determined by continuous lactate production and the fixed buffering capacity of plasma and by the glucose concentration of the PC. With knowledge of these parameters, methods for predicting pH as a function of time, platelet count, and O2 and CO2 transport capability of the container have been developed as guidelines for future work.
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We have used a single intensive chemotherapy regimen in the treatment of young patients with diffuse, aggressive, malignant lymphomas. There were two major histologic types of lymphoma in our series: lymphoblastic lymphomas, which presented most often with mediastinal tumor (64%), and undifferentiated lymphomas (mostly Burkitt's lymphomas), which occurred predominantly in the abdomen (86%). Our objective was to examine the determinants of prognosis in a uniformly treated patient group that included 31 children (2-16 yr) and 34 young adults 17-35 yr). ⋯ In the undifferentiated lymphoma subgroup, histology (i.e., Burkitt's lymphoma versus non-Burkitt's lymphoma) was not of prognostic significance. Total white count was below 1,000/cu mm in 39% of cycles, and fever associated with granulocytopenia occurred in 17% of cycles. Stomatitis of moderate to severe extent occurred in 50% of cycles.(ABSTRACT TRUNCATED AT 400 WORDS)
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Thrombin Metz and normal thrombin, resulting from activation of the respective prothrombins by factor Xa in the presence of calcium, phospholipid, and factor Va, were purified by chromatography on sulfopropyl Sephadex. By physicochemical criteria, thrombin Metz is identical to normal thrombin. Its functional properties were investigated in some reactions in which thrombin is classically involved. ⋯ This abnormality is not observed in the presence of heparin. However, thrombin Metz binds less tightly to a heparin-Sepharose column, and the direct inhibition of heparin on its activity on S2238 is weaker. From these results, we can predict that the defect in thrombin Metz affects the catalytic site or its vicinity and, jointly or consequently, the region of interaction of thrombin with antithrombin III and heparin.
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Previous studies performed in vitro have indicated that platelets from patients with platelet-type von Willebrand's disease (vWD) have receptors for von Willebrand factor (vWF) already exposed on their surfaces and that the addition of purified vWF or cryoprecipitate to patient platelet-rich plasma under stirring conditions is capable of inducing platelet aggregation and secretion. The present work reports the results of the transfusion of cryoprecipitate in a patient with platelet-type vWD. ⋯ Shortening of the bleeding time occurs only very transiently. The results of this study provide direct evidence that, in patients with platelet-type vWD, an abnormal interaction of their platelets with plasma vWF occurs in vivo, resulting in the absence of high molecular weight vWF multimers, low platelet counts, and impaired hemostasis that are characteristic of this disease.