Since functional differences were found among three major haptoglobin phenotypes, haptoglobin pol... more Since functional differences were found among three major haptoglobin phenotypes, haptoglobin polymorphism was reported to be associated with the risk and clinical course of different inflammatory diseases. The aim of the study was to investigate the Hp polymorphism distribution in Hungarian Crohn's disease patients. 511 Hungarian IBD patients were investigated (Crohn's disease patients: 468, m/f ratio: 233/235, duration 8.2 +/- 6.7 ys, and ulcerative colitis patients: 43, m/f: 22/21, duration: 9.5 +/- 10.6 ys) and 384 healthy subjects served as controls. Hp phenotypes were determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis of sera followed by immunoblotting. Clinical data were come by the questionnaires prepared by the physicians. The frequency of haptoglobin-1 allele was significantly higher in Crohn's disease (0.395) compared to the controls (0.345; OR: 1.24, 95%CI: 1.02-1.52, p = 0.03), but the phenotype distribution showed no such differences. ...
Background. Systemic sclerosis is an autoimmune disease, characterized by widespread small vessel... more Background. Systemic sclerosis is an autoimmune disease, characterized by widespread small vessel vasculopathy, immune dysregulation with production of autoantibodies, and progressive fibrosis. Changes in levels of proangiogenic cytokines had already been determined largely in serum. Our aim was to assess the levels of VEGF in human tears of patients with SSC. Patients and methods. Forty-three patients (40 female and 3 men, mean (SD) age 61 (48-74) years) with SSc and 27 healthy controls were enrolled in this study. Basal tear sample collection and tear velocity investigations were carried out followed by an ophthalmological examination. Total protein concentrations and VEGF levels were determined in tear samples. Results. The average collected tear fluid volume developed 10.4 μL (1.6-31.2) in patients and 15.63 μL (3.68-34.5) in control subjects. The average total protein level was 6.9 μg/μL (1.8-12.3) in tears of patients and control tears contained an average of 4.132 μg/μL (0.1-14.1) protein. In patients with SSc the average concentration of VEGF was 4.9 pg/μL (3.5-8.1) and 6.15 pg/μL (3.84-12.3) in healthy samples. Conclusions. Total protein production was increased because of the smaller tear volume. Decreased VEGF in tear of SSc patients can be explained also by the decreased tear secretion of patients.
A repeated selection of phages from a cyclic heptapeptide phage display library resulted in the e... more A repeated selection of phages from a cyclic heptapeptide phage display library resulted in the enrichment of phages that bind to human alpha-thrombin. One clone of the binding phages that competed with PPACK for binding to thrombin and that had the best binding characteristics was chosen. The amino acid sequence of the peptide displayed on this phage was determined and a peptide with the sequence, Cys-Asn-Arg-Pro-Phe-Ile-Pro-Thr-Cys was synthesised. This peptide, thrombin-inhibiting peptide (TIP), is a full competitive inhibitor of thrombin with an inhibition constant (K(i)) of 0.4974 mM. It lengthened the thrombin time and inhibited thrombin-induced platelet activation and the platelet release reaction, both in a dose-dependent manner. It also reduced platelet adhesion onto a human microvascular endothelial matrix in the parallel plate flow chamber under both arterial and venous shear conditions. Thus, we have selected and synthesised a cyclic heptapeptide that competes with PPACK to bind to thrombin and that can be developed as a direct antithrombin.
Many polymorphisms in vonWillebrand factor (VWF) have been reported and their association with VW... more Many polymorphisms in vonWillebrand factor (VWF) have been reported and their association with VWF plasma levels or cardiovascular diseases has been investigated. The aim of this study was to examine whether the amino acid polymorphism A/T1381 in the VWF A1-domain would affect VWF binding to platelet GPIbalpha. Sixty-one normal individuals were genotyped at the A/T1381 locus. Twenty-one A/A1381 homozygotes, 30 A/T1381 heterozygotes and 10 T/T1381 homozygotes were identified. Remarkably, when compared to VWF of A/T1381 and A/A1381 individuals, VWF of individuals carrying the T/T1381 variant showed an increased affinity for its platelet receptor GPIbalpha under static conditions, as reflected by an increased sensitivity to low concentrations of ristocetin or botrocetin. In addition, also the rVWF-T1381 demonstrated a higher affinity for GPIbalpha than rVWF-A1381. Interestingly, this enhanced affinity of the T/T variant over the A/T and A/A variant was, however, too subtle to affect platelet adhesion under physiological flow conditions, which fully corroborates the normal haemostatic phenotype of all individuals. We demonstrate that the VWF A/T1381 polymorphism plays an important role in inter-individual variability of the affinity of VWF for GPIbalpha, with T/T variants having a higher affinity than A/A and A/T variants, at least under static conditions in vitro. Further genetic linkage and association studies are necessary to establish whether the A/T1381 polymorphism could correlate with an increased risk of thrombotic events.
The fibrinolytic resistance of platelet-rich arterial thrombi received much attention. Clot lysis... more The fibrinolytic resistance of platelet-rich arterial thrombi received much attention. Clot lysis method was used to assess the in vitro fibrinolytic properties in diabetes mellitus. Platelet rich (PRP) clots were formed by addition of thrombin, and lysis was induced by tissue-plasminogen-activator. The coagulation and lysis was followed by the light scattering properties. A special pattern of good initial lysis followed by a second clotting phase was observed in more than half of insulin dependent diabetic patients, while a similar pattern of clot-lysis was only occasionally found in non-insulin dependent diabetes mellitus or in the healthy control group. Following the thrombin activation of washed, gel-filtered platelets, the supernatants possessed an inhibitory action on in vitro lysis of PPP-clots. This suppression was remarkably stronger in IDDM, along with the highest PAI-1 activity concentration ratio of the platelet lysates, compared to plasmatic levels. The relation of this special type of PRP clot-lysis resistance to diabetic vascular complications needs further clarifying and investigations.
ABSTRACT Willebrand-factor antigen level and structure analysis, ristomycin-cofactor assay, beta-... more ABSTRACT Willebrand-factor antigen level and structure analysis, ristomycin-cofactor assay, beta-thromboglobulin and thromboxane metabolite estimations were performed in 22 patients with mixed connective tissue disease to evaluate the incidence and the possible role of haemostatic alterations in the complications occurring during the course of the disease. High levels of Willebrand-factor antigen and ristomycin-cofactor activity were detected in patients with thrombocytopenia, previous thrombotic event, pulmonary vascular lesions and usually in the presence of circulating anti-endothelial antibodies. Increased platelet activation could have been found in antibody positive cases and in patients with thrombocytopenia as well. The documented alterations of endothelial and platelet functions may play important role in the vascular complications of mixed connective tissue disease.
Pathophysiology of Haemostasis and Thrombosis, 1999
... A Case with Necrotizing Vasculitis and Thrombosis Istvan Tornai a , Zoltan Boda a , Agota Sch... more ... A Case with Necrotizing Vasculitis and Thrombosis Istvan Tornai a , Zoltan Boda a , Agota Schlammadinger a , Attila Juhasz b , Nancy Cauwenberghs d ... 2. Ruggeri ZM, De Marco L, Gatti L, Bader R, Montgomery RR: Platelets have more than one binding site for von Willebrand ...
To determine the levels of interleukin 6 (IL-6) and interleukin 8 (IL-8/CXCL-8) in tears collecte... more To determine the levels of interleukin 6 (IL-6) and interleukin 8 (IL-8/CXCL-8) in tears collected from the eyes of normal individuals and of patients with different irritative eye diseases, in order to acquire information on the immunological changes occurring during the early postoperative period following various forms of eye surgery, including penetrating keratoplasty (PKP). IL-6 and IL-8 levels were measured with the aid of human ultrasensitive ELISA kits in the non-stimulated tears of patients in the early postoperative period following PKP or cataract operation, and of patients with acute bacterial conjunctivitis or with a corneal foreign body. The IL-6 and IL-8 concentrations, the total amounts released in a given time and the rates of their release were calculated. A significant increase in IL-6 release was observed in all patient groups compared with the normal controls (p < or = 0.003). The IL-8 release levels were significantly higher in the tears of all patient groups (p < or = 0.03), except for the cataract operation group, where the IL-8 release was not significantly higher (p = 0.053) than in the control samples. No significant differences in IL-6 or IL-8 release were observed when the various patient groups were compared with each other. The release of IL-6 and IL-8 into the tears is enhanced in various anterior segment eye diseases, and this may be used as an indicator of various inflammatory reactions in the early postoperative period.
Immune thrombocytopenic purpura (ITP) patients have characteristic anti-platelet antibodies in th... more Immune thrombocytopenic purpura (ITP) patients have characteristic anti-platelet antibodies in their circulation. To assess the interaction between such antibodies adhering on to a non-physiological surface and human platelets, normal anticoagulated blood was perfused over ITP patient plasma-coated surfaces in a parallel plate flow chamber. At 300 s-1, platelet adhesion to patient plasma-coated glass coverslips (24.0 +/- 10%) was significantly higher than the adhesion to normal plasma-coated surfaces (9.8 +/- 7%). When perfused at 1300 s-1, the adhesion to patient plasma-(5.1 +/- 1.3%) and to normal plasma-(2.5 +/- 1.2%) coated coverslips were significantly weaker. Furthermore, patient platelet binding depended on simultaneous contributions by antibodies and fibrinogen present on the plasma-coated surface, since adherence was antagonized both by normal immunoglobulins added to the perfusate, as well as by the anti-GPIIb/IIIa monoclonal antibody 16N7C2, which competes with fibrinogen for binding to its receptor on the platelet. Accordingly, platelet adhesion was only observed to coverslips coated with the plasma but not the serum of ITP patients. Hence, perfusion of normal platelets over surfaces coated with ITP patient plasma enables a functional assessment of the presence in this plasma of anti-platelet antibodies.
Pentamidine, a highly toxic drug, possesses RGD-peptide (Arg-Gly-Asp)-like antiplatelet actions. ... more Pentamidine, a highly toxic drug, possesses RGD-peptide (Arg-Gly-Asp)-like antiplatelet actions. The objective of this investigation was to study the anticipated profibrinolytic and antiplatelet actions of pentamidine and of pentamidine (bearing guanidino-like groups)-related synthetic peptidomimetic compounds. Platelet aggregation inhibition was assessed using ADP, thrombin, collagen, arachidonic acid and epinephrine as inducers, by aggregometry. In vitro chromogenic plasmin generation tests and clot lysis assays were also performed. Two (assigned as D-2 and D-3) of the synthetic pentamidine-guanidino related molecules were able to inhibit platelet aggregation and simultaneously accelerate in vitro plasmin generation and clot-lysis in the nM range. These dual action antithrombotic agents now need to be tested further to assess their antithrombotic actions in vivo.
Since functional differences were found among three major haptoglobin phenotypes, haptoglobin pol... more Since functional differences were found among three major haptoglobin phenotypes, haptoglobin polymorphism was reported to be associated with the risk and clinical course of different inflammatory diseases. The aim of the study was to investigate the Hp polymorphism distribution in Hungarian Crohn's disease patients. 511 Hungarian IBD patients were investigated (Crohn's disease patients: 468, m/f ratio: 233/235, duration 8.2 +/- 6.7 ys, and ulcerative colitis patients: 43, m/f: 22/21, duration: 9.5 +/- 10.6 ys) and 384 healthy subjects served as controls. Hp phenotypes were determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis of sera followed by immunoblotting. Clinical data were come by the questionnaires prepared by the physicians. The frequency of haptoglobin-1 allele was significantly higher in Crohn's disease (0.395) compared to the controls (0.345; OR: 1.24, 95%CI: 1.02-1.52, p = 0.03), but the phenotype distribution showed no such differences. ...
Background. Systemic sclerosis is an autoimmune disease, characterized by widespread small vessel... more Background. Systemic sclerosis is an autoimmune disease, characterized by widespread small vessel vasculopathy, immune dysregulation with production of autoantibodies, and progressive fibrosis. Changes in levels of proangiogenic cytokines had already been determined largely in serum. Our aim was to assess the levels of VEGF in human tears of patients with SSC. Patients and methods. Forty-three patients (40 female and 3 men, mean (SD) age 61 (48-74) years) with SSc and 27 healthy controls were enrolled in this study. Basal tear sample collection and tear velocity investigations were carried out followed by an ophthalmological examination. Total protein concentrations and VEGF levels were determined in tear samples. Results. The average collected tear fluid volume developed 10.4 μL (1.6-31.2) in patients and 15.63 μL (3.68-34.5) in control subjects. The average total protein level was 6.9 μg/μL (1.8-12.3) in tears of patients and control tears contained an average of 4.132 μg/μL (0.1-14.1) protein. In patients with SSc the average concentration of VEGF was 4.9 pg/μL (3.5-8.1) and 6.15 pg/μL (3.84-12.3) in healthy samples. Conclusions. Total protein production was increased because of the smaller tear volume. Decreased VEGF in tear of SSc patients can be explained also by the decreased tear secretion of patients.
A repeated selection of phages from a cyclic heptapeptide phage display library resulted in the e... more A repeated selection of phages from a cyclic heptapeptide phage display library resulted in the enrichment of phages that bind to human alpha-thrombin. One clone of the binding phages that competed with PPACK for binding to thrombin and that had the best binding characteristics was chosen. The amino acid sequence of the peptide displayed on this phage was determined and a peptide with the sequence, Cys-Asn-Arg-Pro-Phe-Ile-Pro-Thr-Cys was synthesised. This peptide, thrombin-inhibiting peptide (TIP), is a full competitive inhibitor of thrombin with an inhibition constant (K(i)) of 0.4974 mM. It lengthened the thrombin time and inhibited thrombin-induced platelet activation and the platelet release reaction, both in a dose-dependent manner. It also reduced platelet adhesion onto a human microvascular endothelial matrix in the parallel plate flow chamber under both arterial and venous shear conditions. Thus, we have selected and synthesised a cyclic heptapeptide that competes with PPACK to bind to thrombin and that can be developed as a direct antithrombin.
Many polymorphisms in vonWillebrand factor (VWF) have been reported and their association with VW... more Many polymorphisms in vonWillebrand factor (VWF) have been reported and their association with VWF plasma levels or cardiovascular diseases has been investigated. The aim of this study was to examine whether the amino acid polymorphism A/T1381 in the VWF A1-domain would affect VWF binding to platelet GPIbalpha. Sixty-one normal individuals were genotyped at the A/T1381 locus. Twenty-one A/A1381 homozygotes, 30 A/T1381 heterozygotes and 10 T/T1381 homozygotes were identified. Remarkably, when compared to VWF of A/T1381 and A/A1381 individuals, VWF of individuals carrying the T/T1381 variant showed an increased affinity for its platelet receptor GPIbalpha under static conditions, as reflected by an increased sensitivity to low concentrations of ristocetin or botrocetin. In addition, also the rVWF-T1381 demonstrated a higher affinity for GPIbalpha than rVWF-A1381. Interestingly, this enhanced affinity of the T/T variant over the A/T and A/A variant was, however, too subtle to affect platelet adhesion under physiological flow conditions, which fully corroborates the normal haemostatic phenotype of all individuals. We demonstrate that the VWF A/T1381 polymorphism plays an important role in inter-individual variability of the affinity of VWF for GPIbalpha, with T/T variants having a higher affinity than A/A and A/T variants, at least under static conditions in vitro. Further genetic linkage and association studies are necessary to establish whether the A/T1381 polymorphism could correlate with an increased risk of thrombotic events.
The fibrinolytic resistance of platelet-rich arterial thrombi received much attention. Clot lysis... more The fibrinolytic resistance of platelet-rich arterial thrombi received much attention. Clot lysis method was used to assess the in vitro fibrinolytic properties in diabetes mellitus. Platelet rich (PRP) clots were formed by addition of thrombin, and lysis was induced by tissue-plasminogen-activator. The coagulation and lysis was followed by the light scattering properties. A special pattern of good initial lysis followed by a second clotting phase was observed in more than half of insulin dependent diabetic patients, while a similar pattern of clot-lysis was only occasionally found in non-insulin dependent diabetes mellitus or in the healthy control group. Following the thrombin activation of washed, gel-filtered platelets, the supernatants possessed an inhibitory action on in vitro lysis of PPP-clots. This suppression was remarkably stronger in IDDM, along with the highest PAI-1 activity concentration ratio of the platelet lysates, compared to plasmatic levels. The relation of this special type of PRP clot-lysis resistance to diabetic vascular complications needs further clarifying and investigations.
ABSTRACT Willebrand-factor antigen level and structure analysis, ristomycin-cofactor assay, beta-... more ABSTRACT Willebrand-factor antigen level and structure analysis, ristomycin-cofactor assay, beta-thromboglobulin and thromboxane metabolite estimations were performed in 22 patients with mixed connective tissue disease to evaluate the incidence and the possible role of haemostatic alterations in the complications occurring during the course of the disease. High levels of Willebrand-factor antigen and ristomycin-cofactor activity were detected in patients with thrombocytopenia, previous thrombotic event, pulmonary vascular lesions and usually in the presence of circulating anti-endothelial antibodies. Increased platelet activation could have been found in antibody positive cases and in patients with thrombocytopenia as well. The documented alterations of endothelial and platelet functions may play important role in the vascular complications of mixed connective tissue disease.
Pathophysiology of Haemostasis and Thrombosis, 1999
... A Case with Necrotizing Vasculitis and Thrombosis Istvan Tornai a , Zoltan Boda a , Agota Sch... more ... A Case with Necrotizing Vasculitis and Thrombosis Istvan Tornai a , Zoltan Boda a , Agota Schlammadinger a , Attila Juhasz b , Nancy Cauwenberghs d ... 2. Ruggeri ZM, De Marco L, Gatti L, Bader R, Montgomery RR: Platelets have more than one binding site for von Willebrand ...
To determine the levels of interleukin 6 (IL-6) and interleukin 8 (IL-8/CXCL-8) in tears collecte... more To determine the levels of interleukin 6 (IL-6) and interleukin 8 (IL-8/CXCL-8) in tears collected from the eyes of normal individuals and of patients with different irritative eye diseases, in order to acquire information on the immunological changes occurring during the early postoperative period following various forms of eye surgery, including penetrating keratoplasty (PKP). IL-6 and IL-8 levels were measured with the aid of human ultrasensitive ELISA kits in the non-stimulated tears of patients in the early postoperative period following PKP or cataract operation, and of patients with acute bacterial conjunctivitis or with a corneal foreign body. The IL-6 and IL-8 concentrations, the total amounts released in a given time and the rates of their release were calculated. A significant increase in IL-6 release was observed in all patient groups compared with the normal controls (p < or = 0.003). The IL-8 release levels were significantly higher in the tears of all patient groups (p < or = 0.03), except for the cataract operation group, where the IL-8 release was not significantly higher (p = 0.053) than in the control samples. No significant differences in IL-6 or IL-8 release were observed when the various patient groups were compared with each other. The release of IL-6 and IL-8 into the tears is enhanced in various anterior segment eye diseases, and this may be used as an indicator of various inflammatory reactions in the early postoperative period.
Immune thrombocytopenic purpura (ITP) patients have characteristic anti-platelet antibodies in th... more Immune thrombocytopenic purpura (ITP) patients have characteristic anti-platelet antibodies in their circulation. To assess the interaction between such antibodies adhering on to a non-physiological surface and human platelets, normal anticoagulated blood was perfused over ITP patient plasma-coated surfaces in a parallel plate flow chamber. At 300 s-1, platelet adhesion to patient plasma-coated glass coverslips (24.0 +/- 10%) was significantly higher than the adhesion to normal plasma-coated surfaces (9.8 +/- 7%). When perfused at 1300 s-1, the adhesion to patient plasma-(5.1 +/- 1.3%) and to normal plasma-(2.5 +/- 1.2%) coated coverslips were significantly weaker. Furthermore, patient platelet binding depended on simultaneous contributions by antibodies and fibrinogen present on the plasma-coated surface, since adherence was antagonized both by normal immunoglobulins added to the perfusate, as well as by the anti-GPIIb/IIIa monoclonal antibody 16N7C2, which competes with fibrinogen for binding to its receptor on the platelet. Accordingly, platelet adhesion was only observed to coverslips coated with the plasma but not the serum of ITP patients. Hence, perfusion of normal platelets over surfaces coated with ITP patient plasma enables a functional assessment of the presence in this plasma of anti-platelet antibodies.
Pentamidine, a highly toxic drug, possesses RGD-peptide (Arg-Gly-Asp)-like antiplatelet actions. ... more Pentamidine, a highly toxic drug, possesses RGD-peptide (Arg-Gly-Asp)-like antiplatelet actions. The objective of this investigation was to study the anticipated profibrinolytic and antiplatelet actions of pentamidine and of pentamidine (bearing guanidino-like groups)-related synthetic peptidomimetic compounds. Platelet aggregation inhibition was assessed using ADP, thrombin, collagen, arachidonic acid and epinephrine as inducers, by aggregometry. In vitro chromogenic plasmin generation tests and clot lysis assays were also performed. Two (assigned as D-2 and D-3) of the synthetic pentamidine-guanidino related molecules were able to inhibit platelet aggregation and simultaneously accelerate in vitro plasmin generation and clot-lysis in the nM range. These dual action antithrombotic agents now need to be tested further to assess their antithrombotic actions in vivo.
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