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Beta-thromboglobulin plasma levels in the first week after myocardial infarction: Influence of thrombolytic therapy
HIRUDIN - A NEW ANTICOAGULANT IN HAEMODIALYSIS (HD) G. Nowak, E. Bucha, R. Czerwinski*, H. Thieler* Max-planck-Gesellschaft, Research Unit for Pharmacological Haemostaseology, Jena, and Kuratorium ftir Dialyse (KfH)*, Erfurt/Germany
The elimination half life of hirudin is prolonged in patients with impaired renal function. Himdin, which behaves like the endogenic substance creatinine, is not metabolized in the body, but is exclusively filtered glomerularlyin an active form. Hirudin and creatinine clearance (CCL) correlate well with each other (r=0.995). In regular HD the use of blrudin as anticoagulant involves problems because 1) patients undergoing HD in part still have residual renal functions providing CCL values of between 0.1 and 15 ml/rnin/1.73 m2 body surface (NBS) and 2) hirudin does not pass through conventional low flux capillary dialyzers. Using an exact drug monitoring method to measure blood levels of hirudin (Eearin-Clotting-Time, ECT), the residual blood level can be determined following repeated administration of himdin during regular HI). In a pilot study with ten patients, the individual hirudin dose required for efficientItD was determined in five HDs (effective blood level of himdin: 0.7 lag/ml at the end of HD). The patients can be subdivided into three dosage groups. As the first dose, each patient received a bolus of 0.1 mg/kg b. w. himdiu. Group A - Patients with a CCL ranging from 0 to 0.5 ml/min/NBS: 0.06 mg/kg b. w. hirudin. Group B - CCL between 0.5 and 5 ml/min/NBS. Himdin dose in gg/kg b. w. = 0.015 x CCL + 0.05. Group C - CCL ranging from 5 to 15 ml/rnin/NBS:0.12 mg/kg b. w. himdin. Because himdin was found to show a different retention behaviour in the individual HI) patients, frequent controls of the blood level in regular HD are necessary and useful. The ECT method, which is also insensitive to heparin, is well suited for bed-side determination and is essential to HD when using the new, direct-acting thrombin inhibitor and, thus, anticoagulant, hirudin.
PYRAZINE CH/NH-ACIDS: A NEW PHARMACOPHORE OF ANTIPLATELET ACTIVITY J.Petrusewicz, M.Turowski,~H.Foks, B.Pilarski and R.Kaliszan Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdafisk and Faculty of Biotechnology, University of Gdafisk, Gen. J. Hallera 107, 80-416 Gdafisk, Poland
Nine known nonsteroidal antiinflammatory drugs (NSAID) and three new pyrazine derivatives possessing an active methylene moiety (pyrazine CH/NH-acids) were tested with regards to their in vitro and in vivo antiplatelet activity. Concentrations of the agents were determined which caused 25% and 50% inhibition of aggregation of human blood platelets induced by fixed concentrations of ADP, collagen and epinephrine. The in vivo test consisted in determination of percent protection ol mice from pulmonary microembolism caused by injection of a mixture of collagen and epinephrine. The in vitro antiaggregatory activity of the agents studied was rather tow, excepting the inhibition of the collageninduced aggregation by ketoprofen. Several NSAID and two new pyrazine CH/NH-acids appeared highly potent antithrombotic agents in vivo. Activity of NSAID expressed as percent protection against lung thromboembolism in the mouse was demonstrated to depend quantitatively on acid properties of the agents. The new chemical class 0I pharmacologically active agents, pyrazine CH/NH-acids, offers an original pharmacophore which is distinctive from the carboxylic or enolic functionality typical for the established NSAID, and as such, may be devoid of some disadvantages of known antiplatelet drugs. R.Kaliszan, B.Pilarski, K.O~mialowski, H.Strzalkowska-Grad, E.Had, P h a r m . Weekb l. (Sci.Ed.) 7:14l(1985); J.Petmsewicz, R.Gami-Yilinkou, B.Pilarski, R.Kaliszan, P h a r m a c o L Toxic. 70:448(1992); J.Petrusewicz, R.Gami-Yilinkou, R.Kaliszan, B.Pilarski, H.Foks,. Gen. Pharmac.
24:17(1993).
P l a t e l e t a c t i v a t i o n by c a t h e p s i n G ( C G ) : m e c h a n i s m s r e g u l a t i n g a r a c h i d o n i c acid ( A A ) r e l e a s e and s e r o t o n i n (SHT) secretion. S. Rotondo, V. Evangelista, C. Cerletti. Laboratory of Platelet and Leukocyte Pharmacology, Consorzio Mario Negri Sud, &Maria Imbaro, Italy.
Platelet activation by CG, a neutrophil-derived serine protease, culminates in granule secretion and TxB2 production. PLA2 is activated by CG, which induces a concentration (200-800 nM)dependent release of AA in supernatant from 3HAA-lab~led platelets (11 3+0.1% of total, 3 min after CG 800 nM, means__.SEM). The PLA2 inhibitor manoalide (10 ~tM) reduced AA release to 40.3+3.3% of control. It has been previously shown that CG induces a rapid cytoplasmic Ca 2+ ([Ca2+]i! increase mainly, due to extracellular mtlux, suggesting Ca 2÷ channels opening as the first anti main event triggered by CG. We therefore investigated the role of Ca2+ influx in ~G-induced PLA2 activation and 5t{T secretion. The Ca2÷ chelator BAPTA 4 mM and the Ca2÷ channel blocker Ni 2+ 4 raM, reduced AA release to 28.4_+0.5 and 52.8+8.8% of control, respectively. Similarly, 5HT secretion was reduced to 16.1+3.4 and: 20 % of control by BAPTA and Ni2+, respectively. In platelets Ca2+depleted and -permeable by treatment with A23187, in the presence of EGTA 3 mM, the addition of controlled free Ca2÷ quantities determines a concentration=dependent release of AA from 5.5+ 1.6 to 17.1-+3.7% of total radioactivity, at Ca2+ virtually 0 and 800 nM, respectively. Addition of CG to A23187-permeabilized platelets does not modify CaZ+-induced AA release, suggesting that extracellular Ca2÷ influx is the main biochemical event coupled to PLA2 activation in platelets challenged by CG In A23187-permeabilized platelets the increase of controlled free Ca 2÷ also determines a concentrationdependent release of 5-HT from 14.9+2.7 to 65.3+6. I% at Ca 2÷ 0 and 800 nM, respectively. In contrast to PLA2 activation, Ca 2÷induced 51-IT release is strongly potentiated by CG (57.0-2-_1.8 and 68.5_+6.1% of total, at Ca 2+ 13 and 800 nM, respectively). This indicates that although Ca 2÷ influx is required, other mechanisms, such as protein kinase C activation, may participate in triggering 5HT secretion in CG-stimulated platelets.
--335--
B E T A - T H R O M B O G L O B U L I N PLASMA LEVELS IN THE FIRST W E E K A F T E R M Y O C A R D I A L INFARCTION: INFLUENCE OF T H R O M B O L Y T I C THERAPY, A. Salvioni~ GB. Perego, G C Marenzi, S Galli, M.D. Guazzi. Istituto di Cardiologia delrUniversitfi degli Studi, CNR, Fondazione "Monzino", IRCCS, Milano, Italy.
In vitro and in vivo studies have shown both an inhibition and an activation of platelets after thrombolysis in acute myocardial infarction (AMI). Plasma beta-thromboglobulin (BTG), a marker of platelet activity, was evaluated daily during the first week after myocardial infarction in 24 patients who received intravenous streptokinase (group 1) and 26 who did not (group 2). On admission, levels of BTG, as compared to those in healthy subjects (35+9 IU/ml), were similarly augmented in group 1 (105+27 IU/ml) and in group 2 (115:k30 IU/ml); 3 hours later, values averaged 191+58 1U/ml in group 1 (p<0.001 vs baseline) and 95+28 IU/ml in group 2 (not significant vs baseline; p<0.001 between the two groups). From the second to the seventh day, BTG augmented in those patients in both groups with postinfarction angina. From day 5 to 7, patients of group 1 without angina had lower BTG levels than patients of group 2 who had no symptoms. The lowest levels of platelet activity were observed in group 1 reperfused patients. These data indicate that in myocardial infarction an early platelet activation takes place that is enhanced by thrombolytic treatment; recurrence of angina is associated with persistent activation; in the absence of recurrent angina, thrombolysis can limit late platelet activation.
The elimination half life of hirudin is prolonged in patients with impaired renal function. Himdin, which behaves like the endogenic substance creatinine, is not metabolized in the body, but is exclusively filtered glomerularlyin an active form. Hirudin and creatinine clearance (CCL) correlate well with each other (r=0.995). In regular HD the use of blrudin as anticoagulant involves problems because 1) patients undergoing HD in part still have residual renal functions providing CCL values of between 0.1 and 15 ml/rnin/1.73 m2 body surface (NBS) and 2) hirudin does not pass through conventional low flux capillary dialyzers. Using an exact drug monitoring method to measure blood levels of hirudin (Eearin-Clotting-Time, ECT), the residual blood level can be determined following repeated administration of himdin during regular HI). In a pilot study with ten patients, the individual hirudin dose required for efficientItD was determined in five HDs (effective blood level of himdin: 0.7 lag/ml at the end of HD). The patients can be subdivided into three dosage groups. As the first dose, each patient received a bolus of 0.1 mg/kg b. w. himdiu. Group A - Patients with a CCL ranging from 0 to 0.5 ml/min/NBS: 0.06 mg/kg b. w. hirudin. Group B - CCL between 0.5 and 5 ml/min/NBS. Himdin dose in gg/kg b. w. = 0.015 x CCL + 0.05. Group C - CCL ranging from 5 to 15 ml/rnin/NBS:0.12 mg/kg b. w. himdin. Because himdin was found to show a different retention behaviour in the individual HI) patients, frequent controls of the blood level in regular HD are necessary and useful. The ECT method, which is also insensitive to heparin, is well suited for bed-side determination and is essential to HD when using the new, direct-acting thrombin inhibitor and, thus, anticoagulant, hirudin.
PYRAZINE CH/NH-ACIDS: A NEW PHARMACOPHORE OF ANTIPLATELET ACTIVITY J.Petrusewicz, M.Turowski,~H.Foks, B.Pilarski and R.Kaliszan Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdafisk and Faculty of Biotechnology, University of Gdafisk, Gen. J. Hallera 107, 80-416 Gdafisk, Poland
Nine known nonsteroidal antiinflammatory drugs (NSAID) and three new pyrazine derivatives possessing an active methylene moiety (pyrazine CH/NH-acids) were tested with regards to their in vitro and in vivo antiplatelet activity. Concentrations of the agents were determined which caused 25% and 50% inhibition of aggregation of human blood platelets induced by fixed concentrations of ADP, collagen and epinephrine. The in vivo test consisted in determination of percent protection ol mice from pulmonary microembolism caused by injection of a mixture of collagen and epinephrine. The in vitro antiaggregatory activity of the agents studied was rather tow, excepting the inhibition of the collageninduced aggregation by ketoprofen. Several NSAID and two new pyrazine CH/NH-acids appeared highly potent antithrombotic agents in vivo. Activity of NSAID expressed as percent protection against lung thromboembolism in the mouse was demonstrated to depend quantitatively on acid properties of the agents. The new chemical class 0I pharmacologically active agents, pyrazine CH/NH-acids, offers an original pharmacophore which is distinctive from the carboxylic or enolic functionality typical for the established NSAID, and as such, may be devoid of some disadvantages of known antiplatelet drugs. R.Kaliszan, B.Pilarski, K.O~mialowski, H.Strzalkowska-Grad, E.Had, P h a r m . Weekb l. (Sci.Ed.) 7:14l(1985); J.Petmsewicz, R.Gami-Yilinkou, B.Pilarski, R.Kaliszan, P h a r m a c o L Toxic. 70:448(1992); J.Petrusewicz, R.Gami-Yilinkou, R.Kaliszan, B.Pilarski, H.Foks,. Gen. Pharmac.
24:17(1993).
P l a t e l e t a c t i v a t i o n by c a t h e p s i n G ( C G ) : m e c h a n i s m s r e g u l a t i n g a r a c h i d o n i c acid ( A A ) r e l e a s e and s e r o t o n i n (SHT) secretion. S. Rotondo, V. Evangelista, C. Cerletti. Laboratory of Platelet and Leukocyte Pharmacology, Consorzio Mario Negri Sud, &Maria Imbaro, Italy.
Platelet activation by CG, a neutrophil-derived serine protease, culminates in granule secretion and TxB2 production. PLA2 is activated by CG, which induces a concentration (200-800 nM)dependent release of AA in supernatant from 3HAA-lab~led platelets (11 3+0.1% of total, 3 min after CG 800 nM, means__.SEM). The PLA2 inhibitor manoalide (10 ~tM) reduced AA release to 40.3+3.3% of control. It has been previously shown that CG induces a rapid cytoplasmic Ca 2+ ([Ca2+]i! increase mainly, due to extracellular mtlux, suggesting Ca 2÷ channels opening as the first anti main event triggered by CG. We therefore investigated the role of Ca2+ influx in ~G-induced PLA2 activation and 5t{T secretion. The Ca2÷ chelator BAPTA 4 mM and the Ca2÷ channel blocker Ni 2+ 4 raM, reduced AA release to 28.4_+0.5 and 52.8+8.8% of control, respectively. Similarly, 5HT secretion was reduced to 16.1+3.4 and: 20 % of control by BAPTA and Ni2+, respectively. In platelets Ca2+depleted and -permeable by treatment with A23187, in the presence of EGTA 3 mM, the addition of controlled free Ca2÷ quantities determines a concentration=dependent release of AA from 5.5+ 1.6 to 17.1-+3.7% of total radioactivity, at Ca2+ virtually 0 and 800 nM, respectively. Addition of CG to A23187-permeabilized platelets does not modify CaZ+-induced AA release, suggesting that extracellular Ca2÷ influx is the main biochemical event coupled to PLA2 activation in platelets challenged by CG In A23187-permeabilized platelets the increase of controlled free Ca 2÷ also determines a concentrationdependent release of 5-HT from 14.9+2.7 to 65.3+6. I% at Ca 2÷ 0 and 800 nM, respectively. In contrast to PLA2 activation, Ca 2÷induced 51-IT release is strongly potentiated by CG (57.0-2-_1.8 and 68.5_+6.1% of total, at Ca 2+ 13 and 800 nM, respectively). This indicates that although Ca 2÷ influx is required, other mechanisms, such as protein kinase C activation, may participate in triggering 5HT secretion in CG-stimulated platelets.
--335--
B E T A - T H R O M B O G L O B U L I N PLASMA LEVELS IN THE FIRST W E E K A F T E R M Y O C A R D I A L INFARCTION: INFLUENCE OF T H R O M B O L Y T I C THERAPY, A. Salvioni~ GB. Perego, G C Marenzi, S Galli, M.D. Guazzi. Istituto di Cardiologia delrUniversitfi degli Studi, CNR, Fondazione "Monzino", IRCCS, Milano, Italy.
In vitro and in vivo studies have shown both an inhibition and an activation of platelets after thrombolysis in acute myocardial infarction (AMI). Plasma beta-thromboglobulin (BTG), a marker of platelet activity, was evaluated daily during the first week after myocardial infarction in 24 patients who received intravenous streptokinase (group 1) and 26 who did not (group 2). On admission, levels of BTG, as compared to those in healthy subjects (35+9 IU/ml), were similarly augmented in group 1 (105+27 IU/ml) and in group 2 (115:k30 IU/ml); 3 hours later, values averaged 191+58 1U/ml in group 1 (p<0.001 vs baseline) and 95+28 IU/ml in group 2 (not significant vs baseline; p<0.001 between the two groups). From the second to the seventh day, BTG augmented in those patients in both groups with postinfarction angina. From day 5 to 7, patients of group 1 without angina had lower BTG levels than patients of group 2 who had no symptoms. The lowest levels of platelet activity were observed in group 1 reperfused patients. These data indicate that in myocardial infarction an early platelet activation takes place that is enhanced by thrombolytic treatment; recurrence of angina is associated with persistent activation; in the absence of recurrent angina, thrombolysis can limit late platelet activation.