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Biomedical subjects

B Wachowicz

Publications and source records attributed to B Wachowicz.

At least 19 recordsLinked to original sources
PubMed2006

The effect of lipopolysaccharide from Proteus mirabilis on the level of the stable end metabolic products of nitric oxide in blood platelets.

Nitric oxide ((*)NO) plays an important role in a number of physiologic processes. Evidence exists that (*)NO, which stimulates soluble guanylate cyclase and enhances cyclic guanosine monophosphate (cGMP) levels, may inhibit platelet activation. In contrast, during platelet activation induced by different agonists, synthesis of (*)NO in platelets occurs. In these studies, production of the stable end-products of (*)NO-nitrite and nitrate (NO(x)) in human platelets, stimulated by different doses of lipopolysaccharide from Proteus mirabilis (LPS; endotoxin), has been evaluated. LPS is a weak platelet agonist that may activate various steps of platelet activation with the generation of reactive oxygen species. The mechanism of platelet activation induced by the endotoxin is not known. The aim of the present study was to measure the level of nitrite and NO(x) in blood platelets treated with LPS and to examine the level of nitrotyrosine in platelet proteins caused by LPS. Our results show that LPS at a low concentration (6.8 ng/ml) caused a decrease (approximately 80%) in the NO(x) level, whereas at higher concentrations (13.6 and 25 ng/ml) it induced an increase in the NO(x) level (approximately 210% and 260%, respectively). Our results indicate that LPS, like other agonists (thrombin, platelet-activating factor), can stimulate (*)NO production in platelets. After incubating platelets with LPS, we also observed a distinct increase in platelet protein nitration (3-nitrotyrosine).

Blood Platelets↗
PubMed2006

Novel selenoorganic compounds as modulators of oxidative stress in blood platelets.

Many selenoorganic compounds play an important role in biochemical processes and act as antioxidants, enzyme inhibitors, or drugs. The effects of five new synthesized selenoorganic compounds (2-(5-chloro-2-pyridyl)-7-azabenzisoselenazol-3(2H)-one; 2-phenyl-7-azabenzisoselenazol-3(2H)-one; 2-(pyridyl)-7-azabenzisoselenazol-3(2H)-one; 7-azabenzisoselenazol-3(2H)-one; bis(2-aminophenyl) diselenide) on oxidative changes in human blood platelets and in plasma were studied in vitro and compared with those of ebselen, a well known antioxidant. Our studies demonstrated that bis(2-aminophenyl) diselenide has distinctly protective effects against oxidative stress in blood platelets and in plasma. It might have greater biological relevance and stronger pharmacological effects than ebselen.

Blood Platelets↗
PubMed2006

Resveratrol, a natural phenolic compound may reduce carbonylation proteins induced by peroxynitrite in blood platelets.

Resveratrol (3,4',5-trihydroxystilbene) has a very broad range of biological properties, including antiplatelet and antioxidative activity. We investigated in vitro the effect of resveratrol on carbonylation of proteins (indicators of oxidative stress) in blood platelets treated with peroxynitrite (ONOO(-)), a strong biological oxidant and inflammatory mediator. We observed that carbonylation of proteins induced by ONOO(-) (0.1 mmol/l), in the presence of resveratrol (0.25-0.1 mmol/l) is reduced. Resveratrol may scavenge ONOO(-), and may be useful in the prevention of ONOO(-)-related diseases, such as inflammatory and cardiovascular diseases.

Antioxidants↗
PubMed2004

The protective effects of resveratrol against changes in blood platelet thiols induced by platinum compounds.

Cisplatin (cis-diamminedichloroplatinum II, cisPt) is especially useful in the treatment of epithelial malignancies, however, the use of cisplatin is accompanied by several toxicities including haematological toxicity. Contrary to cisplatin, selenium-cisplatin conjugate ((NH(3))(2)Pt(SeO(3)); Se-Pt) has only a slight toxicity effect on blood platelet function. In the mechanism of platinum compounds action on platelets thiols are involved. The aim of the present studies was to examine in vitro how trans-resveratrol (trans-3,4',5-trihydroxystilbene) acts on the levels of platelet glutathione (GSH) and other thiol-containing compounds and how, as an antioxidant, protecs blood platelets against the oxidative stress caused by platinum compounds (cisPt and Se-Pt). To analyse the level of thiols in human blood platelets treated with platinum compounds and with resveratrol the classical technique HPLC has been used. Blood platelets isolated by differential centrifugation of human blood were incubated (30 min, 37 degrees C) with cisPt or Se-Pt at dose of 10 microg/ml that inhibits platelet function and with resveratrol (25 microg/ml). The obtained results indicate that platinum compounds caused in platelets a decrease of both, reduced glutathione (GSH) and free thiols of cysteine (CSH) and cysteinylglycine (CGSH). The pool of these compounds in unreduced form was increased. Platinum compounds caused the reduction of platelet protein thiols. Resveratrol (after 30 min action) at the concentration of 25 microg/ml partly reduced the platinum compounds induced decrease of platelet thiols, particularly thiols in acid-soluble fraction.

Antioxidants↗
PubMed2004

Resveratrol reduces oxidative stress induced by platinum compounds in blood platelets.

The effects of resveratrol (trans-3,4',5-trihydroxystilbene) on the oxidative stress in blood platelets induced by platinum compounds [cisplatin and selenium-cisplatin conjugate] were studied in vitro. The production of thiobarbituric acid reactive substances (TBARS), the level of conjugate diene, the generation of superoxide anion radicals (O2-*) and other reactive oxygen species (O2-*, H2O2, singlet oxygen and organic radicals) were measured by chemiluminescence in blood platelets treated with platinum compounds. Cisplatin at the concentration of 10 microg/ml, as well as selenium-cisplatin conjugate (10 microg/ml) induced oxidative stress in blood platelets: an increase in TBARS, conjugate diene, chemiluminescence and generation of O2-*. In the presence of resveratrol (a natural compound with antioxidant activity) at the concentrations of 1-25 microg/ml, the chemiluminescence, the levels of O2-*, conjugate diene and TBARS were reduced (p < 0.05). We showed that resveratrol at different concentrations (1-25 microg/ml) had a protective effect against oxidative stress in platelets caused by platinum compounds (10 microg/ml) and it diminished platelet lipid peroxidation and reactive oxygen species generation induced by platinum compounds.

Animals↗
PubMed2002

Generation of reactive oxygen species in blood platelets.

The generation of superoxide anion radicals (O2*-) and the other reactive oxygen species (ROS) was estimated by means of cytochrome c reduction and chemiluminescence, as well in resting blood platelets and in platelets stimulated by thrombin in the presence or absence of some inhibitors of pathways involved in platelet activation. We used allopurinol (xanthine oxidase inhibitor), wortmannin (PI 3-kinase inhibitor) and staurosporine (protein kinase C inhibitor). To determine the involvement of the glutathione in ROS generation, we used L-buthionine sulfoximine (BSO) which blocks GSH synthesis. Our results confirmed that thrombin stimulates the production of ROS concomitant with metabolism of arachidonate and production of malonyldialdehyde (MDA) in blood platelets (P < 0.05) and showed that, in the presence of inhibitors, the generation of ROS in platelets (resting and stimulated) was reduced. This indicates that xanthine oxidase, PI 3-kinase or protein kinase C take part in the formation of ROS in blood platelets. Moreover, adhesion of platelets to fibrinogen and secretion of adenine nucleotides from platelets after wortmannin and staurosporine action was also inhibited. BSO not only decreased GSH level, but also reduced the amount of ROS; a correlation between the depletion of GSH and the decrease of ROS was observed (R = -0.987; P < 0.02). It is concluded that in blood platelets, ROS are produced in the receptor-mediated signaling pathways and platelet activation (arachidonic acid metabolism, the glutathione cycle, metabolism of phosphoinositoides and due to xanthine oxidase). Our results support the importance of ROS in platelet function.

Animals↗
PubMed2001

Cancer procoagulant and blood platelet activation.

The effects of cancer procoagulant (CP), cysteine protease (EC 3.4.22.26), on the pig blood platelet secretory process and platelet aggregation have been studied. The response of platelets to CP was compared with the response of these cells to thrombin. The obtained results show that blood platelets treated with CP (0.5, 1, 2.5, and 5 microg/ml, 2-30 min, 37 degrees C) released adenine nucleotides (P < 0.05) and proteins (P < 0.05). The secretion of compounds from blood platelets after incubation with CP does not correlate with the release of platelet lactic dehydrogenase activity (marker of cell lysis) into the extracellular medium. In comparison with thrombin action, CP stimulates secretory process to a smaller extent than thrombin alone. In the presence of CP, the thrombin action is suppressed (P < 0.05). We noticed that CP does not induce platelet aggregation.

Adenine↗
PubMed2001

The generation of superoxide anion in blood platelets in response to different forms of Proteus mirabilis lipopolysaccharide: effects of staurosporin, wortmannin, and indomethacin.

Lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria may activate blood platelets. The aim of our study was to evaluate the effects of different forms of Proteus mirabilis LPS and isolated lipid A and polysaccharide part on the production of superoxide radicals in blood platelets and to estimate the role staurosporin, wortmannin and indomethacin on this process. We compared the generation of superoxide radicals in platelets treated with LPS after preincubation with inhibitors of the signal transduction pathways, namely staurosporin (inhibitor of protein kinase C), wortmannin (inhibitor of phosphoinositide 3-kinase), and indomethacin (inhibitor of cycloxygenase). Our results demonstrate that all LPS molecules and their fragments caused a stimulation of O2- generation in platelets (P<.5). LPSS1959 had the strongest stimulatory effect. Straurosporin and wortmannin, but not indomethacin inhibited O2- production in LPS-stimulated platelets. Staurosporin (8 nM) and wortmannin (50 nM) caused about 50% inhibition of thrombin-induced O2- generation in platelets, while indomethacin (10 microM) had only a slight inhibitory effect on this process. Our results provide support that in LPS- and thrombin-activated platelets, at least part of O2- generation in platelets, while indomethacin (10 microM) had only a slight inhibitory effect on this process. Our results provide support that in LPS- and thrombin-activated platelets, at least part of O2- is generated due to the activation of the enzymes (protein kinase C and phosphoinositide 3-kinase) involved in signal transduction pathway. Cycloxygenase seems to be not involved in this process.

Androstadienes↗
PubMed2001

Antioxidant activity of resveratrol in endotoxin-stimulated blood platelets.

Resveratrol (3,4',5-trihydroxystilbene) is a natural molecule with antioxidant action. It is also considered to be a molecule with antiplatelet, anticancer and anti-inflammatory action. The effects of trans-resveratrol on the reactive oxygen species (ROS) generation and thiobarbituric acid-reactive substances (TBARS) in blood platelets induced by endotoxin (lipopolysaccharide, LPS) or thrombin were studied in vitro. The production of superoxide radicals (O2.-) and other reactive oxygen species (H2O2, singlet oxygen, and organic radicals) in the presence of resveratrol was measured by a chemiluminescence method in resting blood platelets and platelets stimulated by LPS (0.3 microg/ 10(8) platelets) or thrombin (2.5 U/10(8) platelets). We have shown that resveratrol (6.25-100 microg/ml) inhibits chemiluminescence and generation of O2.- in blood platelets. It has an inhibitory effect on the production of ROS and TBARS in platelets caused by LPS or thrombin.

Animals↗
PubMed2001

Studies on pig blood platelet responses to peroxynitrite action.

The action of peroxynitrite (ONOO(-)) on pig blood platelet function was studied. Incubation of washed blood platelets with ONOO(-) (0.062-2 mM) caused strong, dose- and time-dependent inhibitory effects on adhesion of resting and thrombin-stimulated platelets to collagen and on platelet aggregation induced by thrombin. The platelet responses were measured 10 s after addition of peroxynitrite to platelets ('zero time') and after 60 min incubation of platelets with ONOO(-). Exposure of blood platelets to peroxynitrite (60 min) brought about platelet lipid peroxidation assessed by the thiobarbituric acid method but did not cause any changes in blood platelet proteins as determined by SDS-polyacrylamide gel electrophoresis.

Animals↗
PubMed2001

Adhesion of thrombin-stimulated and unstimulated blood platelets to collagen in the presence of Proteus mirabilis lipopolysaccharides.

Adhesion of blood platelets to collagen may be involved in pathogenesis of septic shock after damage of endothelial cells by LPS or inflammatory cytokines. Therefore, analysis of platelet adhesion in the presence of endotoxin seems to be of great importance. We studied in vitro the effects of LPSs (S1959, R110, R45) from Proteus mirabilis (smooth and rough types differing significantly in their composition) on the adhesion of unstimulated and thrombin-stimulated platelets to collagen. The adhesion was measured by a static method as absorbance of cell attached proteins. In this work we report that adhesion of resting platelets to collagen was stimulated by all tested LPSs. The effects were dependent on the doses of LPSs. In the presence of LPSs the inhibition of adhesion of thrombin-treated platelets to collagen was observed. The results presented in this paper indicate that LPSs from Proteus mirabilis may act directly on blood platelets and stimulate adhesion of resting platelets to collagen. On the other hand, LPSs can have an inhibitory effect on adhesion of thrombin-stimulated platelets to collagen.

Animals↗
PubMed2001

Role of phosphoinositide 3-kinase in adhesion of platelets to fibrinogen stimulated by cancer procoagulant.

Cancer procoagulant, cysteine proteinase (CP; EC 3.4.22.26) activates factor X and functions in the absence of factor VII. CP may also change the platelet function. It induces an increase of platelet adhesion to collagen and fibrinogen. Using wortmannin--the inhibitor of phosphoinositide 3-kinase (PI 3-K)--we studied the role of this enzyme in the action of cancer procoagulant on blood platelet adhesion in vitro. Wortmannin (25, 50 and 100 nM, 30 min, 37 degrees C) caused a reduction of platelet adhesion to fibrinogen (P<0.01) when blood platelets were stimulated by both 0.2 U/ml thrombin (IC(50)approximately 75 nM) and by 1 microM ADP (IC(50)approximately 60 nM). We observed that after CP treatment the adhesion of thrombin-activated and ADP-stimulated platelets to fibrinogen was augmented. The potentiated by CP adhesion of activated platelets to fibrinogen was reduced after preincubation of platelets with wortmannin (50 nM, 30 min, 37 degrees C). We conclude that in adhesion of platelets to fibrinogen stimulated by CP PI 3-K take place.

Adenosine Diphosphate↗
PubMed2001

[Biological activity of resveratrol].

Resveratrol is a phytoalexin found in many plants, mainly in grapes. It has been shown to prevent coronary heart diseases and to exert a variety of anti-cancer and anti-inflammatory effects.

Animals↗
PubMed2001

The effect of resveratrol on the platelet secretory process induced by endotoxin and thrombin.

The effect of resveratrol (trans-3,4',5-trihydroxystilbene) on the release of adenine nucleotides and proteins from blood platelets activated by lipopolysaccharide (LPS), from Proteus mirabilis and by thrombin, were studied. Thrombin stimulated the release of adenine nucleotides from dense granules and proteins from alpha-granules. The LPS (0.3 microg/10(8) platelets, 5 min, 37 degrees C), like thrombin (2.5 U/10(8) platelets, 5 min, 37 degrees C) was found to cause a release of adenine nucleotides and proteins (p <0.05). Resveratrol (6.25-100 microg/ml, 30 min, 37 degrees C) had a different effect on the platelet release reaction caused by either LPS or thrombin. The results indicated that resveratrol inhibited, in dose-dependent manner, the secretory process (release of adenine nucleotides and proteins) induced by thrombin (p <0.05), but it significantly stimulated the liberation of proteins from blood platelets activated by LPS (p <0.05).

Adenine Nucleotides↗
PubMed2001

The effects of peroxynitrite on pig platelet lipid peroxidation and the secretory process induced by thrombin.

The effects of peroxynitrite on the blood platelet secretory process and lipid peroxidation, were investigated. Peroxynitrite (ONOO-) is a reactive oxidant produced by the reaction of NO with the superoxide radical, which can diffuse into the cell and change the cell function. This study showed that treatment of blood platelets with ONOO- (0.03-2 mM) caused a dose-dependent inhibition of adenine nucleotides release but had no effect on the thrombin-induced protein exocytosis. Incubation of platelets with ONOO- (60 min, 0.25-2 mM) induced platelet lipid peroxidation. In thrombin-activated platelets pretreated with ONOO- for approximately 10 s (zero time), the level of thiobarbituric acid reactive substances, such as malonyldialdehyde (MDA) was reduced. It is suggested that the reduced amount of MDA in thrombin-stimulated platelets caused by ONOO- was due to inhibition of cyclo-oxygenase via nitration of tyrosine residues.

Adenine Nucleotides↗
PubMed2000

The effects of granulocyte colony stimulating factor on chemiluminescence and lipid peroxidation of blood platelets treated with cisplatin.

The effects of granulocyte colony stimulation factor (G-CSF) at concentrations of 0.08, 0.8 and 8 microg/ml on reactive oxygen species (ROS) generation and lipid peroxidation induced by cisplatin in pig blood platelets were investigated. The level of reactive oxygen species (O2, H2O2, singlet oxygen and organic radicals) generated in platelets was measured by the chemiluminescence method. Lipid peroxidation was determined by the thiobarbituric acid technique and was expressed as thiobarbituric acid reactive substances. G-CSF at the concentration of 0.08 microg/ml had a strong inhibitory effect (about 60% inhibition) on the production of ROS in the isolated pig platelets. This cytokine also significantly reduced lipid peroxidation in control platelets and platelets treated with cisplatin (p<0.05). In the presence of G-CSF in the incubation medium (0.8 microg/ml) cisplatin-induced generation of ROS was also reduced (p<0.05). This study demonstrates that G-CSF has a protective effect against the oxidative stress in blood platelets caused by cisplatin.

Animals↗
PubMed2000

Vitamin C suppresses the cisplatin toxicity on blood platelets.

The effects of vitamin C on the oxidative stress in blood platelets induced by cisplatin were studied. In the presence of vitamin C we measured in blood platelets the production of thiobarbituric acid reactive substances (TBARS), the generation of superoxide radicals (O2*-), other reactive oxygen species (H2O2, singlet oxygen and organic radicals) and catalase activity. Vitamin C at a low concentration (0.1 mM), like cisplatin (20 microM), induced blood platelet oxidative stress: an increase of TBARS, chemiluminescence and generation of superoxide radicals. After treatment of blood platelets with vitamin C at a high concentration (3 mM), chemiluminescence (p>0.05), the levels of O2*- (p<0.01) and TBARS (p<0.002) were reduced. We have shown that vitamin C at a high concentration (3 mM) had a protective effect against oxidative stress in platelets caused by cisplatin (20 microM). It diminished platelet lipid peroxidation and reactive oxygen species generation induced by cisplatin. In the presence of vitamin C, the catalase activity was suppressed.

Animals↗