Biochemical studies of two patients with the gray platelet syndrome. Selective deficiency of platelet alpha granules.

Gerrard, Jon M.; Phillips, David R.; Rao, G. H. R.; Plow, EF; Walz, Daniel A.; Ross, Russell; Harker, Laurence A.; White, James G.

doi:10.1172/jci109823

Cited by 277 publications

(83 citation statements)

References 37 publications

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“…An anti-thrombospondin polyclonal antibody was also reported to inhibit aggregation of platelets at low but not high concentrations of (0.1 U/ml) thrombin [13]. Gray platelets, which lack a-granule constituents, such as thrombospondin, fibrinogen, fibronectin and FVIII : vWf, show an extensive decrease in aggregation in response to low concentrations of thrombin and collagen [62,63]. However at higher concentrations of thrombin and collagen, Gray platelets aggregated to a similar extent to normal platelets [63].…”

Section: Discussionmentioning

confidence: 99%

Characterization of an anti‐thrombospondin monoclonal antibody (P8) that inhibits human blood platelet functions

Boukerche

McGregor

1988

European Journal of Biochemistry

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Stimulated human blood platelets release thrombospondin, an α‐granule glycoprotein of 450 kDa. The aim of this work was to characterize an anti‐thrombospondin monoclonal antibody (P8) in order to study the role of thrombospondin in platelet functions. The presence of thrombospondin receptor sites on resting and thrombin‐stimulated platelets of three Glanzmann's thrombasthenia patients and normal donors was investigated using the P8 monoclonal antibody. Monoclonal antibody P8 was extensively characterized using ELISA, immunoprecipitation, immunoadsorbent affinity chromatography combined with tryptic peptide map analysis and crossed immunoelectrophoretic techniques. Labelled P8 bound strongly to thrombin‐stimulated normal platelets (n= 14917 ± 420, mean ± SD) (Kd= 9.2 ± 3.0 nM) and poorly to resting platelets (n= 2697 ± 1278) (Kd= 24.8 ± 18.6 nM). Moreover, the number of binding sites for P8 on thrombin‐stimulated platelets from three Glanzmann's thrombasthenia patients, lacking the IIb‐IIIa glycoprotein complex, were found similar to normal samples. F(ab')2 fragments of P8 inhibited aggregation of, and reduced secretion from, washed platelets stimulated by low concentrations of thrombin (0.05–0.06 U/ml) and collagen (0.5–0.6 μg/ml). F(ab')2 fragments of P8 inhibited thrombin‐induced platelet aggregation, but did not reduce fibrinogen binding (n) nor affect its dissociation constant (Kd). Inhibition of platelet aggregation by P8 suggests that thrombospondin plays an active role in promoting platelet aggregation, at low concentrations of thrombin and collagen. Normal binding of P8 to thrombin‐stimulated Glanzmann thrombasthenic platelets indicates the presence of a thrombospondin receptor on the platelet surface distinct from the GPIIb‐IIIa complex.

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Section: Discussionmentioning

confidence: 99%

Characterization of an anti‐thrombospondin monoclonal antibody (P8) that inhibits human blood platelet functions

Boukerche

McGregor

1988

European Journal of Biochemistry

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“…Platelets from platelet-rich plasma were washed twice with an equal volume of CCD (93 mmol/L sodium citrate, 70 mmol/L citric acid, and 140 mmol/L dextrose, pH 6.5) containing 5 mmol/L adenosine and 3 mmol/L theophylline. 17 The final pellet was resuspended in Hank's balanced salt solution without calcium and adjusted to 50 000 platelets per microliter. Human platelet-poor plasma was prepared from platelet-rich plasma by centrifugation at lOOOg for 10 minutes.…”

Section: Methodsmentioning

confidence: 99%

Organization of von Willebrand factor on surface-activated platelets.

Escolar¹,

White²

1993

Arterioscler Thromb

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The distribution and organization of von Willebrand factor (vWF) multimers on platelets after surface activation have not been fully characterized. In the present study, washed human platelets were allowed to interact with Formvar-coated, electron microscope grids for 20 minutes at 37°C and then fixed. After fixation, cells were washed and then incubated with buffer alone, human plasma, human plasma preincubated with ristocetin (1.2 mg/niL), purified human vWF plus ristocetin, or bovine plasma.

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“…Он был охарактеризован как патологическое состояние, сопро-вождающееся тромбоцитопенией, достаточно мягкими проявлениями кровоточивости и наличием агрануляр-ных тромбоцитов в периферической крови. Биохими-ческими и электронно-микроскопическими методами было показано, что все органеллы, кроме α-гранул, не изменены и присутствуют в нормальных количест-вах [21][22][23]. Предполагается, что причиной возникно-вения этого синдрома является неспособность мегака-риоцитов к образованию специфических везикул и наполнению их α-гранулярными компонентами [24].…”

Section: а наследственные формы тромбоцитопатийunclassified