Excerpt The mechanisms responsible for the low platelet count in idiopathic thrombocytopenic purpura are not well understood despite the careful studies by many competent investigators The thrombo

Immunologic mechanisms in idiopathic and neonatal thrombocytopenic purpura

THE hemorrhagic tendency of thrombocytopenic animals can be controlled temporarily by transfusions of fresh platelet concentrates.1 , 2 The clinical value of platelet transfusions has previously been noted.3 4 5 6 Studies in animals have shown that maximal hemostatic effects can be expected when the transfusion of platelets is followed by a sustained elevation of their level in the blood.7 Clinical studies comparable to those in animals have not been possible, however, because of the variations in bleeding manifestations of untreated thrombocytopenic patients and the difficulties encountered in carrying out well controlled studies during medical or surgical emergencies. In view of the widening use of . . .

Transfusions of fresh platelet concentrates to patients with secondary thrombocytopenia.

RECENT developments in the therapy of certain types of cancer with growth-suppressing agents, which are usually myelotoxic, as well as the threat of mass exposure to ionizing radiation, have focused increasing attention on the problem of collection, preservation and transfusion of platelets. Thus, bleeding due to thrombocytopenia is one of the most significantly limiting factors in the chemotherapy of leukemia and lymphoma. It is theoretically possible that, if a drastic but temporary depression of abnormal cell production could be obtained by various chemotherapeutic agents even at the expense of severe bone-marrow injury, lengthy remissions would occur in certain types of . . .

Collection, preservation and transfusion of platelets; with special reference to the factors affecting the survival rate and the clinical effectiveness of transfused platelets.

IT has been found that suspensions of blood platelets in normal saline are agglutinated by A- B- and O-sera, just as these sera agglutinate red blood cells of the corresponding blood group. It is thus possible to establish four blood groups for the blood platelets, similar to the blood groups in erythrocytes.

ABO groups in blood platelets

Publisher Summary This chapter discusses the isolation of subcellular components. In many cases, isolated cell structures can be tested for their retention of function, that is, for their capacity to mediate or carry out complex synthetic reactions in vitro. This is often the reason for their isolation; however, a test for function can also serve as a test of the isolation method itself. An important application of cell fractionation is its use in the isolation of substances that have a characteristic intracellular localization. The ideal isolation procedure is easy to define; it is the method that yields the desired intracellular components as they exist in the cell, unchanged and uncontaminated, and in quantitative yield. Methods that give quantitative yields often involve serious alterations in form, structure, or composition; procedures that preserve the morphology often destroy activity and function. Purity and homogeneity of the product are rarely achieved. The first problem to arise in any cell fractionation concerns the selection of source material. The choice is often fixed by the nature of the experiment, and existing isolation procedures can need modification to fit the material under investigation.

Allen H. Minor

Papers

A method for separating and concentrating platelets from normal human blood.