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At least 181 records · Page 10Linked to original sources
PubMed1982

[Nosographic and diagnostic classification of congenital thrombocytopathies. Clinical interpretative notes].

Substantial progress has been made in recent years in the understanding of platelets and their functions. This has permitted a more reasonable classification of congenital platelet diseases, primarily thanks to the standardization of haemostasis and platelet function tests. A comparison is made between the pictures best defined in 17 cases studied at the S. Matteo Polyclinic in recent years. This brought out certain contradictions and suggested that further study in greater depth is required.

Blood Platelet Disorders↗
PubMed1981

Constitutional thrombocytopathy with subnormal response to thromboxane A2.

A new type of congenital platelet dysfunction was found in a young woman presenting a life-long bleeding disorder. The known types of thrombopathia and von Willebrand's disease were excluded by appropriate investigations. The platelets were morphologically normal, underwent normal shape change and contraction and synthesized thromboxane A2 (TXA2) normally. The release reaction was abnormal and the aggregation response to ADP, adrenalin, collagen, thrombin, sodium arachidonate and vasopressin was depressed due to decreased sensitivity of the platelets to prostaglandin endoperoxides and TXA2. Platelet cAMP content was increased.

Adolescent↗
PubMed1993

Failure to mobilize intracellular calcium in response to thrombin in a patient with familial thrombocytopathy characterized by macrothrombocytopenia and abnormal platelet membrane complexes.

We report a mother and son who were found to have macrothrombocytopenia, prolonged bleeding time, and abnormal platelet responses to thrombin. Transmission electron microscopy performed on the son's platelets demonstrated an unusual arrangement of membrane complexes formed by association of the open canalicular and dense tubular systems. Number and appearance of platelet alpha-granules, dense bodies, and mitochondria were normal. These platelets demonstrated normal agonist-induced Ca2+ flux in response to collagen and supranormal responses to arachidonic acid but displayed no increase in intracellular free Ca2+ in response to thrombin. Platelet surface glycoproteins IIb-IIIa, Ib, and granular membrane protein-140 measured by fluorescence-activated flow cytometry, along with platelet content of von Willebrand factor and fibrinogen, were normal. The von Willebrand factor binding function of GP-Ib on these platelets was also normal. We believe that this family demonstrates a unique macrothrombocytopenia syndrome characterized by deficient Ca2+ mobilization in response to thrombin that is not related to a defect in GP-Ib.

Adolescent↗
PubMedDate not supplied

[Utility of desmopressin in 4 cases of thrombocytopathies associated with giant platelets].

Shear-induced aggregation requires the platelet glycoprotein complexes (Gp), the von Willebrand factor (vWf) and ADP. The Bernard Soulier syndrome (BS) and the gray platelet syndrome (GPS) are platelet function defects characterized by absence of GP Ib/IX and alpha granules, respectively, with mucocutaneous hemorrhages, prolonged bleeding time (BT) and moderate thrombocytopenia in both syndromes. There are reports that desmopressin (DDAVP) shortens the BT in some patients with platelet dysfunction. The purpose of this study was to evaluate the response t(DDAVP) in four female patients (2 with GPS plus Marfan's disease and 2 BS). All had bleeding episodes, BTs > 10 minutes, platelet counts (PC) between 40-88 x 10(9)/L and defects in platelet aggregation. The DDAVP was administered at a dose of 0.3 microgram/kg in 15 to 30 mL of isotonic saline given by slow intravenous drip in 30 to 45 min. All patients were studied before and after DDAVP administration (BT, PC, platelet factor, mean platelet volume, factors F.VIII:C, FvW:Ag, FvW:RiC of, and platelet aggregation). After DDAVP infusion the patients had a BT < 6 min, and increased levels of F. VIII:C, FvW:Ag and FvW:RiC of (> 100 Ul/dL), and the bleeding disappeared. We conclude that there was a good response to DDAVP probably associated with improved platelet adhesion, and increases in the multimers of the von Willebrand factor.

Adolescent↗
PubMed1997

Megakaryocytes and inherited thrombocytopenias.

Inherited thrombocytopenias may be divided into two groups. In the first group, there is no marked thrombocytopathy. Although numerous in the bone marrow, megakaryocytes often are abnormal cytologically. A dysmegakaryocytopoiesis with defective platelet production is suggested but remains to be evidenced. In the second group, thrombocytopenias are accompanied with variable thrombocytopathy. The functional and biochemical platelet abnormalities responsible for these different thrombocytopathies often are well elucidated. The study of the relations with the occurrence of thrombocytopenia constitutes an interesting field of investigation.

Bernard-Soulier Syndrome↗
PubMed1988

[The thrombocytic beta-thromboglobulin level of patients with blastic leukemia and chronic myeloleukemia].

The thrombocytic beta-thromboglobulin (beta-TG) level--a specific globulin secreted by the alpha-granules--is an important criterion in the contemporary diagnosis of acquired thrombocytopathies. The beta-TG was determined by the radioimmunologic test of the firm "Amersham" in thrombocytic lysates and thrombocyte-poor plasma of 54 persons: 24 patients with acute leukemia, 14 patients with chronic myeloid leukemia and 15 healthy controls. The leukemic patients were with a preliminary proved thrombocytopathy type "empty thrombocytic pool disease" which had been proved via aggregation measurement by the ATP and ADP levels in the thrombocytes and by the thrombocytic factor 4 level. While the intraplatelet beta-TG concentration in acute leukemia and chronic myeloid leukemia was found unchanged, in the patients with acute leukemia its secretion in the plasma was decreased (154.71 + 16.77 ng/10(5) platelets). The data interpretation shows that in these malignant hemopathies the alpha-granules do not take part in the "empty pool disease". In acute leukemia the pathogenesis of the thrombocytopathy is determined by the so-called "thrombocytic secretion paresis" which is confirmed by the thrombocytic factor 4 low level.

Blood Platelets↗
PubMedDate not supplied

Comparison of platelet glass bead retention techniques in patients with clinical bleeding disorders.

Platelet glass bead retention by the Salzman and infusion pump techniques were compared in 36 control individuals, 10 patients with von Willebrand's syndrome and four patients with thrombocytopathies. No significant differences between the results of the two assays were observed. Eleven percent or less of the control individuals had diminished platelet glass bead retention. The mean percentage platelet retention of the von Willebrand's group and the thrombocytopathy group was less than the mean platelet retention of the control group. However, at least 50 percent of the patients with von Willebrand's syndrome had normal platelet retention by both methods. In the thrombocytopathy group, glass bead retention was more consistently diminished. Although an inverse correlation existed between the duration of bleeding time and the platelet retention assays, consistently diminished platelet retention results were observed only when the bleeding time was 18 minutes or longer. It has been concluded by us that while the glass bead retention assays may be helpful in characterizing certain types of platelet disorders, they are not useful screening assays in the diagnosis of von Willebrand's syndrome.

Blood Coagulation Disorders↗