Blood Platelet Concentration Research Articles

Description of a closed plastic bag system for the collection and cryopreservation of leukapheresis-derived blood mononuclear leukocytes and CFUc from human donors.

Hemopoietic stem cells were collected from blood by means of continuous-flow centrifugation. The therapeutic use of large quantities of autologous blood stem cells requires a suitable, reliable and easily practicable cryopreservation technique which prevents loss of cell number and viability. This paper describes a closed plastic bag system consisting of one part for the collection and freezing of blood-derived mononuclear cells (MNC), among them granulocyte/macrophage progenitor cells (CFUc), and of a second part for thawing the cryopreserved cells and washing them free of DMSO before transfusion to a patient. In a series of 20 leukaphereses, the average number of collected MNC and CFUc was about 11 x 10(9) and 8 x 10(5) respectively. The recovery rate of the leukapheresis derived MNC and CFUc after cryopreservation, thawing, and washing was demonstrated to be 90 per cent of better. Sequential leukaphereses in the same donor showed little effect on red and white blood cell concentration. However, there was a significant decrease in the donor's blood platelet concentration prior to the third leukapheresis.

Increased in vivo and in vitro platelet function in type II- and type IV-hyperlipoproteinemia

<h2>Abstract</h2> Platelet function in vivo and in vitro was examined in 10 patients with type IIa-, 8 patients with type IIb-, and 16 patients with type IV-hyperlipidemia (HLP) and 24 control subjects closely matched for age and sex. Patients with type IIb- and IV-HLP showed significantly shorter template bleeding times in the presence of similar blood platelet concentrations. Increased platelet factor 3-availability in intact platelet-rich plasma (PRP) and PRP exposed to collagen was observed in all patient groups. Plasma antiheparin activity was increased in patients with type IIa- and type IV-HLP. Platelet adhesiveness, platelet aggregation and ¹⁴C-serotonin release in response to ADP, epinephrine and collagen, as well as plasma von Willebrand factor activity, were generally not increased in either patient group. Increased platelet function in endogenous HLP may be related to both increased platelet turnover secondary to premature atherosclerotic disease and abnormalities of platelet lipid composition induced by HLP-plasma.

Fibrin-blood platelet interaction in a contracting clot.

The interaction of fibrin and blood platelets was studied by measuring tension development in clots containing different ratios of these two components. Isometric tension attained a saturation value (MT) when plotted as a function of the concentration of either component at a constant concentration of the other. The value of MT increases linearly with the minimal platelet concentration (Ps) required in order to reach saturation at various different fibrin concentrations. A linear relationship also holds in a plot of Ps versus the logarithm of the corresponding fibrin concentration. When the cylindrical clots contracted isotonically, the velocity, normalized with respect to the momentary length, was found to be constant. This velocity decreased in an hyperbolic manner with increasing fibrin concentration at a constant concentration of blood platelets. The results are interpreted in terms of a three-dimensional network in which the blood platelets serve as contractile cross-bridges connecting fibrin fibres. Tension development is assumed to be accompanied by the reduction of the angle between fibrin fibres. An attempt was made to calculate the isometric tension developed by a platelet.

Abnormalities of Megakaryocytes in W/Wv Mice

Abstract Megakaryocytopoiesis was evaluated in genetically anemic mice of the W/Wv genotype and was found to be abnormal. Concentration and size of blood platelets were normal. Megakaryocytes were decreased in number in tibial marrow and spleen, and the size of mature megakaryocytes was increased.

Abnormalities of Megakaryocytes in Sl/Sld Mice

Abstract Megakaryocytopoiesis was evaluated in Sl/Sld mice and their heterozygous and homozygous normal (+/+) littermates. Sl/Sld mice had a normal concentration of blood platelets which were of normal size. Numbers of megakaryocytes in bone marrow and spleen were reduced, but individual megakaryocytes were larger than normal.

Annotation: pure red cell aplasia.

Pure red cell aplasia (PRCA) was first described by Kaznelson (1922) as an anemia due to an almost complete cessation of erythropoiesis, but without leukopenia or thrombocytopenia. This condition usually can be clearly distinguished from aplastic anemia in which low blood white cell and platelet concentrations accompany the anemia (Van Der Weyden and Firkin, 1972). In PRCA the bone marrow has an isolated absence of erythroblasts with normal granulocytopoiesis and megakaryocytopoiesis (DiGiacomo et al., 1966; Jacobs et al., 1959), whereas in aplastic anemia all three hematopoietic lineages are markedly reduced (Van Der Weyden and Firkin, 1972). In children PRCA has been called “chronic (congenital) hypoplastic anemia,” the Diamond-Blackfan anemia, or erythrogenesis imperfecta (Diamond and Blackfan, 1938; Gasser, 1957; Tsai and Levin, 1957). In adults it has been termed isolated aplastic anemia, aplastic crisis, erythroblastopenia, erythrophthisis, chronic erythrocytic hypoplasia, red cell aplastic anemia, or red cell agenesis (Gasser, 1957; Tsai and Levin, 1957). Although these cases could represent a variety of pathogenetic mechanisms they all have in common an isolated absence of marrow erythroblasts and are now considered together as cases of PRCA.

Resin hemoperfusion: a new treatment for acute drug intoxication.

A resin-column hemoperfusion system was used to treat four patients with profound, life-threatening drug intoxication. The column contained 650 g of pyrogen-free resin, Amberlite XAD-2. The resin is uncharged and has a cross-linked, polystyrene macroreticular structure with particular surface attraction for high-molecular-weight, lipid-soluble molecules. Blood was pumped through the column at a flow rate of 300 ml per minute for three hours. Two patients had secobarbital, one a mixture of glutethimide-butabarbital-ethchlorvynol, and one amobarbital intoxication. In all patients the column clearances of these drugs were markedly superior to known clearances with hemodialysis. A transient, modest fall in blood platelet concentration followed hemoperfusion. No serious clinical toxic effects were noted. The resin-column hemoperfusion system was technically simpler, consistently more effective and clinically superior to hemodialysis.

Effect of Endotoxin on the Kinetics of Hemopoietic Colony-Forming Cells in Irradiated Mice

Hemopoietic recovery in irradiated animals is hastened by the action of bacterial endotoxin given as a single injection either before or shortly after irradiation (1). Bone marrow cellularity, peripheral blood granulocyte, erythrocyte, platelet, and lymphocyte concentrations, and survival are favorably affected and, in the mouse, the number of endogenous spleen colonies is increased (2-4). The fact that endotoxin is effective when given after irradiation rules out several modes of action. These include chemical protection, hypoxia, increased numbers of stem cells at the time of irradiation, and decreased sensitivity of the stem cells to the immediate killing action of radiation. Among the possibilities remaining are recovery of cells that otherwise would die on the resumption of mitosis, early resumption of mitosis, and shortening of the cell cycle. Means of exploring such possibilities are provided by the technique for enumerating colony-forming units (CFU) developed by Till and McCulloch (5-7). Suspensions containing hemopoietic cells are injected into recipient mice whose endogenous spleen colony formation has been suppressed by lethal irradiation and the resulting spleen colonies are counted 10 days later. The transplanted colonyforming units have many of the characteristics of stem cells (8), and in the present experiments we assume that their enumeration provides an assay of stem cells. The experiments presented here concern population changes in colony-forming units in spleen and femoral marrow resulting from an injection of Salmonella typhosa endotoxin 24 hours before or a few minutes after irradiation with 400 rads.

Blood clotting defect in hibernating ground squirrels (Citellus tridecemlineatus).

In investigating the hypocoagulability of the blood during hibernation, multiple plasma-clotting factors, numbers of platelets, and hematocrits were determined in 17 hibernating 13-lined ground squirrels and compared with levels in 23 nonhibernating ground squirrels. Human plasma was used as the standard in procoagulant assays. At the time of withdrawal of the blood from the aortas of hibernating animals, their rectal temperatures ranged from 6.9 to 8.6 C. Significant differences between active and hibernating animals were found in the whole-blood clotting times (210 and 315 sec), partial thromboplastin times (45.5 and 109.3 sec), plasma prothrombin (443 and 698 U/ml), 1-hr serum residual prothrombin (27 and 449 U/ml), factor VIII (165 and 35%), factor IX (359 and 188%), and blood platelet concentration (445,150 and 47,940/mm3). No decisive changes were demonstrated in the prothrombin times or levels of factors V, VII, X, XI, XII, or fibrinogen. Inhibitors were not detected. Both thrombocytopenia and plasma defects seemed to contribute to the impairment of the blood-clotting mechanism during hibernation.

Susceptibility to Thrombosis in Normal Young, Aging, Cortisone-treated, Heparinized and X-irradiated Hamsters as Tested by Topical Application of Thrombin

Abstract 1. Thrombin applied topically to the everted cheek pouch of the hamster produced platelet and not red thrombi in exposed, uninjured blood vessels with circulating blood. Red thrombi were produced in stagnant blood. Thrombus formation occurred in the venules for the most part and seldom in arterioles or capillaries. 2. An in vivo test for platelet thrombus susceptibility, based on the thrombin reaction and the resistance of the hamster to thrombosis, has been described. 3. Thrombus susceptibility, measured by the thrombin test, increased with age and during cortisone treatment, and decreased after heparin injection and following large doses of whole body x-irradiation. 4. The thrombin susceptibility test could be correlated with the platelet count in x-irradiated hamsters, showing a relatively critical minimum concentration of blood platelets (100,000/cu.mm.) required for platelet thrombosis. 5. The relationship of platelet concentration to platelet thrombus formation and predisposition to hemorrhage has been discussed.

Blood Platelets in Heterophil Anaphylaxis

SummarySerum of rabbits immune to sheep erythrocytes injected intravenously in appropriate doses in guinea pigs and dogs produced a drastic reduction of the concentration of blood platelets even though these quantities of serum provoked only moderate shock or no shock.