Cancer procoagulant stimulates platelet adhesion.
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Adenosine Diphosphate↗
Biomedical subjects
T Krajewski
Publications and source records attributed to T Krajewski.
Response of blood platelets to resveratrol.
The phytochemical resveratrol (3,4',5-trihydroxystilbene), which is found in grapes and wine, has been reported to have a variety of anti-inflammatory, anti-platelet and anti-carcinogenic effects. The aim of the present study was to evaluate the effects of trans-resveratrol on adhesion of blood platelets to collagen, as well as on thrombininduced platelet aggregation and malonyldialdehyde (MDA) production in vitro. Pretreatment of platelets with resveratrol (50 microg/ml) inhibited their adhesion to collagen (by 32% in resting platelets and by 57% in thrombin-activated platelets after 1 h of preincubation) and thrombin-induced platelet aggregation (by 59% after 30 min preincubation). Resveratrol also had an inhibitory effect on the generation of malonyldialdehyde (a marker of thromboxane A(2) synthesis) measured as thiobarbituric reactive substance in thrombin-activated platelets.
Journal Article↗
Selenium compounds inhibit the biological activity of blood platelets.
The action of inorganic forms of selenium (Se) on blood platelet aggregation, secretion and the arachidonate pathway in vitro was studied. It was shown that sodium selenite, after 30 min preincubation, inhibited platelet aggregation induced by 0.1 U/ml of thrombin and by 10 microM ADP (about 30% inhibition of aggregation after pretreatment of platelets with 10(-4) M of Se). Contrary to sodium selenite, sodium selenate did not affect the platelet aggregation induced by either agonist. Pretreatment of blood platelets with sodium selenite resulted in a statistically significant decrease in adenine nucleotide secretion ( P < 0.01) and release of malonyldialdehyde (MDA), produced in equal amounts to TXA(2) , in thrombin-stimulated platelets ( P <0.001). However, selenite did not change the level of MDA/TXA(2) in sodium arachidonate-stimulated platelets. We conclude that the inhibitory effects of sodium selenite on platelet activation could be the result of decreased synthesis and release of secondary agonists (TXA(2), ADP) in stimulated platelets. It is also possible that sodium selenite blocks the release of arachidonic acid from platelet membranes via phospholipases.
Journal Article↗
The effect of cis-diamminedichloroplatinum, selenite and a conjugate of cisplatin with selenite [(NH3)2Pt(SeO3)] on oxidative stress in blood platelets measured by chemiluminescence method.
The effects of cisplatin, sodium selenite and a conjugate of these compounds [(NH3)2Pt(SeO3)] on the generation of free radicals in blood platelets measured by chemiluminescence method were investigated in vitro. In platelets incubated with cisplatin (20 microM, 5 min) a dose-dependent increase of chemiluminescence was observed (p < 0.05). Contrary to the stimulatory action of cisplatin (20 microM) on the production of free radicals, selenite (1 microM) and its conjugate with cisplatin (20 microM) had only slight effects on the oxidative stress in platelets (p < 0.05). The observed increase of chemiluminescence after cisplatin action correlated with a decrease of platelet free thiols present in reduced glutathione. Pre-treatment of blood platelets with buthionine sulfoximine (50 microM, 1 h, 37 degrees C) leading to a decrease of glutathione reduced the cisplatin-induced generation of free radicals in these cells (p < 0.05).
Animals↗
Response of human blood platelet membrane to sodium selenite.
It was demonstrated that incubation of blood platelets with sodium selenite (1-100 microM) resulted in a dose- and time-dependent loss of platelet thiols (both glutathione and protein -SH groups). The effects of sodium selenite on platelet membrane lipid fluidity by the EPR spin-labelling method was also investigated. We showed there were no alterations in membrane fluidity at the deeper regions (12-DOXYL-Ste) in lipid bilayer, a slight increase (approx. 7%, p < 0.03) of h +1/h0 for spin probe 5-DOXYL-Ste was monitored. The amount of Triton-insoluble protein fraction isolated from platelets after incubation (60 min) with selenite was significantly elevated (p < 0.006). It has been suggested that limited increase in lipid fluidity at the surface regions in the lipid bilayer of the platelet membrane in selenite-treated platelets may be the result of alteration in lipid-protein interactions caused by protein conformational changes.
Animals↗
Inhibitory effect of resveratrol on free radical generation in blood platelets.
Resveratrol (3,4',5-trihydroxystilbene), a compound found in many plants, has been shown to prevent coronary heart diseases and to exert a variety of antiinflammatory and anticancerogenic effects. It is effective in lowering the level of serum lipids and in inhibiting platelet aggregation. We evaluated the effect of trans-resveratrol on the production of free radicals in pig blood platelets and showed that resveratrol inhibited the production of different reactive oxygen species (O2*-, H2O2, singlet oxygen and organic radicals) measured by the luminol-dependent chemiluminescence in resting platelets (P < 0.05). Resveratrol inhibited also the generation of radicals in platelets activated by thrombin (P < 0.05). Treatment of platelets with resveratrol at concentrations of 6.25 and 12.5 microg/ml caused a statistically insignificant increase in the production of O2*- in these cells, as measured by reduction of cytochrome c; however, at higher doses (25, 50 and 100 microg/ml) resveratrol distinctly reduced the generation of O2*- in platelets (P < 0.05). We suggest that free radicals play an important role in the reduced reactivity of blood platelets induced by resveratrol.
Animals↗
Comparative effects of selenite and selenite on the glutathione-related enzymes activity in pig blood platelets.
The effects of inorganic selenium (Se) compounds (sodium selenite and selenate) on the activities of glutathione-related enzymes (glutathione peroxidase, glutathione-S-transferase [GST] and glutathione reductase [GR]) in pig blood platelets were investigated in vitro. GST activity in blood platelets treated with 10(-4)M of selenite was reduced to 50%, whereas no decrease GST activity was observed after the treatment of platelets with the same dose of selenate. In platelets incubated with physiological doses (10(-7) and 10(-6)M) of Se compounds, the activity of glutathione peroxidase (GSH-Px) was enhanced (about 20%). GR activity after the exposure of platelets to tested Se compounds was unaffected.
Animals↗
Effects of cisplatin and selenite on the level of thiols in pig blood platelets.
The level of free sulfhydryl groups of glutathione and proteins in pig blood platelets after short lasting incubation (30 min.) of these cells with cisplatin (cis-diamminedichloroplatinum II) and sodium selenite was investigated in vitro. The concentration of the platelet thiols after sodium selenite or cisplatin treatment distinctly decreased (p < 0.001). Pretreatment of blood platelets with sodium selenite at the low concentration (0.1 microM) protected platelet glutathione against the reaction with cisplatin (p < 0.001). The present study shows that in blood platelets after the incubation with cisplatin the GS-platinum complex was formed. The results of our experiments demonstrated also that the extracellular GSH (1 mM) had the protective effect against cisplatin-induced peroxidation of platelet lipids.
Animals↗
Binding of copper to porcine apoceruloplasmin.
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Animals↗
Green Spring criteria for medical necessity of outpatient treatment and its use in a mental health utilization review program.
The authors have developed a two-tiered method for utilization review of outpatient mental health services. The methodology looks at initial and continued treatment evaluation and uses diagnosis, symptoms, plan of treatment, and the Global Assessment Scale (GAS) among other indicators to determine appropriateness of treatment. Preliminary program experience has been positive and is included.
Ambulatory Care↗
Interaction of heterologous fibrinogens with human platelet receptors.
The interaction of ADP-stimulated human platelets with human 125I-fibrinogen as well as with pig and bovine fibrinogens was analysed. It was found that the fibrinogens studied were bound to the same platelet receptors but the affinity of animal preparations was about half the value observed for human fibrinogen (in a homologous system).
Adenosine Diphosphate↗
Protective effect of ceruloplasmin against lipid peroxidation in blood platelets.
The effect of ceruloplasmin on the peroxidation of blood platelet lipids was tested. Using thiobarbituric acid reactivity for measuring lipid peroxidation it was shown that ceruloplasmin inhibited peroxidation of pig platelet lipids induced by UV-irradiation, and much less when enzymatic peroxidation was stimulated by thrombin.
Animals↗
[A micromethod of analysis of adenine nucleotides in human blood platelets].
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Adenine Nucleotides↗
Avian thrombocyte thrombospondin.
A high molecular weight glycoprotein (450,000) was obtained from thrombin-treated duck thrombocytes by barium citrate adsorption technique followed by heparin-agarose affinity chromatography. Amino acid composition (high number of acidic amino acids and cystine) as well as carbohydrate contents (1.3 per cent hexosamine, 0.9 per cent sialic acid and 1.5 per cent hexose) showed similarity to mammalian platelet thrombospondin.
Amino Acids↗
Purification and partial characterization of goose ceruloplasmin.
The preparation and properties of ceruloplasmin from goose blood plasma are described. Ammonium sulfate was used to precipitate the crude protein followed by adsorption and elution from DEAE-Sephadex A-50. Further treatment with an ethanol-chloroform mixture and Sephadex G-200 yielded an intensely blue protein possessing a high degree of chemical purity and biological activity. Goose ceruloplasmin, existing in two forms, appears to be a single polypeptide, apparent Mr121,300, with an A610/A280 ratio of 0.07. Copper represented 0.32%, which corresponded to six atoms of copper per protein molecule. Although the amount of EPR-detectable copper was the same as in mammalian ceruloplasmins there were some differences in EPR parameters, mainly in A parallel. Goose ceruloplasmin's amino acid composition, although similar in many residues to human ceruloplasmin, was lower in tyrosine, cystine/cysteine, and acidic amino acids. Valine was found as the N-terminal amino acid. Hexose, hexosamine, sialic acid, and fucose accounted for 6.65% of the weight. Goose protein contained only half the sialic acid of human ceruloplasmin. Two values for Km using either p-phenylenediamine (0.64 and 0.053 mM) or o-dianisidine (0.76 and 0.15 mM) were evaluated from Lineweaver-Burk plots. EPR studies on reactions with water radiolysis products at cryogenic temperatures allowed us to discover that goose ceruloplasmin, like human and bovine ceruloplasmins, possesses superoxide dismutase activity.
Amino Acids↗
Activation of duck prothrombin by factor Xa and thrombin.
Prothrombin isolated from duck sodium citrate plasma was activated in a system containing duck factor Xa and calcium ions. Polyacrylamide gel electrophoresis showed that intermediates and the final product, thrombin, of Mr in the range 21 500-52 000 were present in the incubation mixture Serine and isoleucine were found to be the N-terminal amino acids of the intermediate form 1 and thrombin, respectively.
Animals↗
Terminal plasmin degradation products D and E of duck fibrinogen and their effect on polymerization of fibrin.
Duck fibrinogen (Mr 320 000) treated with streptokinase-activated human plasminogen in the presence of calcium ions was hydrolysed to terminal core fragments D and E. They were isolated from the digest by: (1) ion-exchange chromatography on DEAE-cellulose, (2) gel filtration on Sephadex G-100, and (3) affinity chromatography with the use of fibrin monomers coupled to CNBr-activated Sepharose. When the native D fragment, D1 was additionally digested by plasmin in the presence of EDTA, more degraded forms D2 and D3 appeared. Molecular weight of D1, D2, D3 and E estimated on SDS-polyacrylamide gel electrophoresis is 100 000, 89 000, 80 000 and 50 000, respectively. It was found that after reduction with 2-mercaptoethanol the fragments D1 and D3 consisted each of three polypeptide chains: alpha, beta, gamma: the gamma-chain of D3 remnant was more degraded (Mr 24 000) as compared with the gamma-chain of D1 remnant (Mr 42 000). Polymerization of both duck and pig fibrin monomers was inhibited by fragments D1 but not by D3.
Animals↗
UV light-induced changes in washed pig platelets.
The effect of ultraviolet radiation (UV-A, 360 nm) on the thrombin-induced aggregation of washed pig platelets as well as on the release of adenine nucleotides and proteins was studied. The level in platelets of adenine nucleotides, mainly ADP and ATP, decreased rapidly following the exposure of platelets to a high dose of UV-A (0.5 W/cm2, 30 min). Through thrombin-induced aggregation of irradiated platelets was inhibited, the release reaction occurred. The amount of the released adenine nucleotides and proteins was, however, dependent on the dose of UV light. These findings suggest that UV-A light can stimulate the platelet release reaction.
Adenine Nucleotides↗