Signification Clinique Du Test De Coombs Direct Dans Les Affections Neoplasiques: Etude De 265 Cas

Direct Coombs tests were performed in 265 patients with solid tumors, leu-kemias and malignant lymphomas. The frequency of highly positive Coombs tests varied from 5.52 in the solid tumors (13 % for the carcinomas) to 52 % in chronic lymphotic leukemia. A secondary autoimmune hemolytic anemia, without antibody, was present in 2 cases of solid tumors and in one case of Hodgkin's disease. A dubious or slightly positive Coombs test was frequently observed without signs of increased hemolysis. On the other hand, a strongly positive Coombs test was associated with an acute hemolysis in most cases but in patients with macroglobulinemia. Biological tests usually considered as characteristic for secondary hemolytic anemia (reticulocytosis, unconjugated bilirubin, urinary excretion of urobilinogen, serum iron, granulopoiesis/erythropoiesis ratio) have not an unequivocal significance : they may be normal in cases with true hemolytic anemia or abnormal in patients with a normal survival time of the red cells. The presence of more than 2 abnormal tests is however indicative for the diagnosis of hemolytic anemia, especially if there is no liver deficiency.

Use of Hydrogen Bubbles for Quantitative Determination of Time-Dependent Velocity Fields in Low-Speed Water Flows

Improved flow-visualization methods based on the hydrogen-bubble technique are described. Use of “combined-time-streak markers” allows quantitative measurement of the instantaneous velocity field in a plane as a function of time in low-speed water flows. Adaptation to a great variety of situations using different probe techniques is possible. Disturbance to the flow is very small. Adequate accuracy is obtainable. The method offers the advantage of simultaneous visual observation of the flow structure and quantitative measurement of velocity over a finite region. It also allows some types of measurement not previously possible. Limitations of the method include its restriction to low-speed water flows and the observation of fluctuations only at low frequencies. Practical difficulties occur due to probe frangibility and problems of obtaining uniform bubble production. Part 1 describes the underlying concepts, summarizes the history of the method and describes operating experience to date at Educational Services, Incorporated, and Stanford University. Part 2 is a detailed analysis of the uncertainties in velocity measurements using combined-time-streak markers formed by hydrogen bubbles.