Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of activation of plasminogen by streptokinase and tissue-type-plasminogen activator on platelet activation and the membrane glycoproteins (GPs) that mediate platelet adhesion and aggregation are not yet fully defined. To clarify effects on platelets during activation of plasminogen in vitro, we used monoclonal antibodies (MoAbs), flow cytometry, and platelets surface-labeled with 125I to characterize changes in receptors for fibrinogen (GPIIb-IIIa), von Willebrand factor (GPIb), and collagen (GPIa-IIa). Activation of plasminogen in plasma with pharmacologic concentrations of plasminogen activators did not degrade GPIIb-IIIa or GPIb, and caused only a modest decrease in GPIa. In washed platelets GPIIb-IIIa was extensively degraded by plasmin at 37 degrees C in the absence of exogenous Ca2+, conditions that destabilize the IIb-IIIa complex. Degradation of GPIb in washed platelets displayed a similar although less-marked dependence on temperature and the absence of Ca2+. The binding of activation-specific MoAbs did not increase during activation of plasminogen in plasma. We conclude that during pharmacologic fibrinolysis, reported inhibition of platelet function in plasma is not due to degradation of platelet-adhesive receptors. In addition, platelet activation observed during thrombolytic therapy does not appear to be a direct consequence of plasminogen activation.
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PMID:Dependence of plasmin-mediated degradation of platelet adhesive receptors on temperature and Ca2+. 216 24

Platelet transfusion therapy became to be largely used in the last 20 years. This development was related to the progress of plastic bags and of blood cell separators. In parallel the platelet immunology has moved from serological techniques to molecular biology. The biochemical characterization of platelet antigen and the genetic basis of the polymorphism was discovered in the last years. The platelet RNA PCR amplification and specific oligonucleotide typing are now accessible to several laboratories. Five major human platelet antigen (HPA) systems are completely characterized. HPA-1 (PLA, Zw) localized on platelet glycoprotein GPIIIa correspond to a single amino acid substitution (leu<==> Pro 33). HPA-2 (Ko, Sib) present on GPIb is due to a Thre<==>Met substitution in 145. HPA-3 formerly Bak, Lek correspond to a polymorphism in 843 (Ile<==>ser) on GPIIb. HPA-4 (Pen, Yuk) as HPA1 is on GPIIIa but in a different location (Arg<==>Gln 143). HPA-5 (Br, He, Zav) and HPA-6 (Ca, Tu) are on GPIa and GPIIIa respectively. The major progress made in the field of platelet immunology has not yet been largely applied to the clinical situation of platelet transfusion. We can hope that it could help in the future to a better platelet-transfusion compatibility and consequently an improved clinical efficacy of platelet transfusion.
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PMID:Platelet alloantigens and transfusion. 833 18

To determine the relevance of inherited prothrombotic risk factors in sudden hearing loss, we investigated 85 patients with sudden hearing loss of >/= 60 dB for the presence of inherited prothrombotic risk factors. The FV G1691A, FII G20210A, GPIa C807T, GPIIIa PIA1/A2, PAI-1 4G/5G, t-PA Alu repeat ID, MTHFR C677T and CBS 844ins68 genotypes were investigated. Allele frequencies found in patients were compared to those of 85 healthy control subjects of the same ethnic background using Chi-squared and odds-ratio analysis. The frequency of the GPIa807T allele was significantly elevated in patients compared to controls. In addition, allele frequency and genotype distribution of GPIa was significantly elevated in the patient group without recovery after 3 months of sudden hearing loss onset. Allele frequencies of all other prothrombotic risk factors investigated here did not differ from those of the control subjects. The single-nucleotide polymorphism of GPIa C807T seems to play a role as a prognostic factor in recovery from sudden hearing loss.
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PMID:Platelet GPIaC807T polymorphism is associated with negative outcome of sudden hearing loss. 1510 3

A novel fish protein having anticoagulant and antiplatelet properties was enzymatically extracted from the marine fish, yellowfin sole (Limanda aspera) and purified to homogeneity producing an overall purification fold of 206.6. MALDI-TOF mass spectroscopic and SDS-PAGE analysis identified the purified protein as 12.01 kDa single-chain monomeric protein. It inhibited the activated coagulation factor XII (FXIIa) by forming an inactive complex regardless of Zn2+ mediation, and was named, yellowfin sole anticoagulant protein (YAP). In addition, YAP act to antagonize platelet membrane glycoprotein integrin, to arrest platelet aggregation. However, YAP was not able to block the adhesion of platelets to collagen, which mediate via major collagen receptors, GPIa/IIa on platelet membrane. Furthermore, YAP did not possess plasminogen activator-like activity to activate fibrinolysis. In fact, our findings indicate that YAP binds with FXIIa and platelet membrane integrins to inhibit thrombosis in vitro.
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PMID:A novel anticoagulant purified from fish protein hydrolysate inhibits factor XIIa and platelet aggregation. 1576 84