Biomedical subjects

J C Lormeau

Publications and source records attributed to J C Lormeau.

At least 37 records · Page 2Linked to original sources

PubMed1995

Molecular profiling and weight determination of heparins and depolymerized heparins.

The recently proposed calibrant LHN-1 (lot F537; henceforth designated F537), for the molecular weight (MW) determination by high-performance size-exclusion chromatography of heparins, is shown here to have a range too narrow to allow for the accurate MW determination of all low molecular weight heparins (LMWHs). We have recently demonstrated, by this same methodology, that a chemically degraded benzyl ester of unfractionated heparin, heparin mass calibrator (HMC), is a better calibrant. Weight-average MW, number-average MW, peak MW, and dispersity values were calculated with F537, HMC, and by a reference narrow-range-calibration method for various LMWHs and unfractionated heparins. Values for these parameters determined with HMC were not significantly different from those determined by the reference method until the MW of the substance exceeded 15.0 kDa. In contrast, the MW profile obtained with F537 was appreciably different from that obtained by the reference method for samples with MWs > 7.5 kDa. The range exhibited by HMC should allow this calibrant to be used for both LMWHs and unfractionated heparins.

Heparin↗

PubMed1995

Antithrombin III affinity dependence on the anticoagulant, antiprotease, and tissue factor pathway inhibitor actions of heparins.

To investigate AT-III affinity dependence on heparin's actions, heparin (UH) was fractionated on an AT-III-Sepharose column into a high (HAH) and a low affinity (LAH) fraction. Molecular profiling revealed a molecular weight of 11.8 kDa for (UH), 12.6 kDa for HAH, and 10.6 kDa for LAH. The USP anticoagulant potencies were found to be: UH = 160 U/mg, HAH = 198 U/mg, and LAH = 42 U/mg. The anticoagulant effects of each of these fractions were proportionate to the USP potencies. However, protease generation inhibitory activities did not follow the same order. All fractions were also tested for their interactions with tissue factor pathway inhibitor (TFPI). No significant differences were noted on the anti-Xa effects of TFPI with these fractions. Administration of each fraction to primates resulted in equivalent release of TFPI. In a model of jugular vein clamping induced venous occlusion, all agents produced a dose-dependent antithrombotic action. HAH produced a 60 to 70% stronger antithrombotic effect than LAH or UH. Simultaneous administration of TFPI markedly augmented the antithrombotic actions of both UFH and LAH. The effect of TFPI on the antithrombotic activity of HAH was weaker than that on LAH. These observations suggest that AT-III affinity is not the sole determinant of the antithrombotic actions of heparin. The endogenous release of TFPI may contribute to the antithrombotic actions of heparin and related glycosaminoglycans. Furthermore, TFPI is capable of AT-III independent amplification of the antithrombotic actions of both UH and LAH, suggesting a crucial role of this polyvalent inhibitor in the control of thrombogenesis.

Animals↗

PubMed1995

Comparison of a low-molecular-weight heparin (nadroparin calcium) and unfractionated heparin as adjunct to coronary thrombolysis with alteplase and aspirin in dogs.

BACKGROUND: Low-molecular-weight heparins may have a higher benefit to risk ratio than unfractionated heparin in preventing perioperative thrombosis. The antithrombotic effects of low-molecular-weight heparins, given as adjunctive therapy to alteplase and aspirin, have not previously been compared with those of unfractionated heparin in experimental models of coronary artery thrombosis. METHODS: Occlusive coronary thrombosis was induced in 5 groups of 10 dogs by placing a copper coil into the left anterior descending coronary artery. After 1 h of occlusion, intravenous alteplase (0.1 mg/kg bolus followed by 0.01 mg/kg/min for 30 min), and aspirin (bolus of 5 mg/kg) were administered in combination with one of the following study treatments given intravenously for 2 h: placebo (group 1); unfractionated heparin (200 IU/kg bolus followed by 100 IU/kg/h, group II); the low-molecular weight heparin, nadroparin calcium, in three different doses (100 IU/kg bolus followed by 50 IU/kg/h, group III; 200 IU/kg bolus followed by 100 IU/kg/h, group IV; and 300 IU/kg followed by 150 IU/kg/h, group V). Coronary patency was assessed with angiography at 10 min intervals and hemostasis parameters were measured at baseline, after 1 h of occlusion, and 30 and 120 min after commencing drug administration. RESULTS: Optimal reperfusion [Thrombolysis in Myocardial Infarction (TIMI) flow grade 3 without reocclusion] was more frequently observed in groups II (6/10), IV (8/10) and V (9/10) than in groups I (1/10) and III (3/10) (P < 0.05). Groups II and IV had similar patency rates (P = NS) and were therefore assumed to represent equivalent antithrombotic doses. Both nadroparin calcium and unfractionated heparin effectively prevented new thrombin generation as shown by repeated measurements of thrombin-antithrombin III complex levels in plasma. At equivalent antithrombotic doses, nadroparin calcium (group IV) was associated with significantly lower steady state values than standard heparin (group II) for activated partial thromboplastin time (41.3 +/- 48.9 versus 134.7 +/- 61.6 s), anti-Xa levels (2.4 +/- 0.5 vs 3.4 +/- 0.9 U/ml) and anti-IIa levels (0.8 +/- 0.1 versus 2.1 +/- 0.7 U/ml). CONCLUSION: Both nadroparin calcium and unfractionated heparin significantly enhance alteplase-induced thrombolysis in aspirin-treated dogs. At equivalent antithrombotic doses, nadroparin calcium was associated with less prolongation of the activated partial thromboplastin time and lower steady-state anti-Xa and anti-IIa activities.

Animals↗

PubMed1995

The effect of the synthetic pentasaccharide SR 90107/ORG 31540 on thrombin generation ex vivo is uniquely due to ATIII-mediated neutralization of factor Xa.

The inhibition of thrombin generation (TG) was studied in plasma from human volunteers after single subcutaneous administrations of 4000, 8000 or 12,000 anti-Xa units (i.e., 6, 12 or 18 mg) of the synthetic pentasaccharide (SR 90107/ORG 31540) (SP). SP impaired TG in plasma for up to 18 h after injection, and the time-courses of TG and factor Xa inhibitions were similar. In untreated plasma supplemented in vitro with SP to obtain the same anti-Xa activity as in ex vivo samples, equivalent TG inhibitions were observed thus showing that no transformed SP molecules were involved in the TG inhibition ex vivo. Functional as well as immunological assay of TFPI indicated that subcutaneous injection of 12,000 anti-Xa units of SP did not induce any TFPI release, whereas under the same conditions, 13,000 IU of Fraxiparine produced a significant rise of TFPI in plasma. The plotting of TG inhibition versus SP concentration could be fitted with a good correlation (r = 0.94) to the graphical representation linking [ATIII-SP] to [SP]. These results demonstrate that following subcutaneous administration to man, SP inhibits TG ex vivo and likely in vivo exclusively through the same selective ATIII-mediated inhibition of factor Xa as the one elicited in vitro.

Antithrombin III↗

PubMed1994

Pharmacokinetic and antithrombotic properties of two pentasaccharides with high affinity to antithrombin III in the rabbit: comparison with CY216.

This study compares the pharmacokinetic and the antithrombotic properties of two pentasaccharides with high affinity to antithrombin III with those of a conventional low molecular weight heparin, CY216, in the rabbit. On a weight basis, SR 90107A/ORG 31540 (natural pentasaccharide [NPS]) and SR 80027A/ORG 31550 (sulfated pentasaccharide [SPS]) were, respectively, 4.7 and 26 times more potent antifactor Xa inhibitory agents than CY216. They were devoid of antithrombin activity, whereas the antifactor Xa/antithrombin ratio of CY216 was 3.8. After bolus intravenous administration, the clearance (mL/kg/h) of CY216 decreased from 91 +/- 27 for the dose of 12.5 U/kg to 49 +/- 14 for the dose of 50 U/kg and then remained constant up to the highest dose tested (500 U/kg). The clearance of NPS was unrelated to the dose and comparable to that of CY216 over 50 U/kg, whereas that of SPS was 10 times lower. Consistent results were observed after continuous intravenous infusions for 9 hours and subcutaneous administration. The duration of the antithrombotic effect was compared after a single subcutaneous injection of 250 U/kg of either compound in the stasis-Wessler model using human serum as thrombogenic stimulus. Two hours after the injection, the three compounds provided a thrombus prevention of greater than 95% and mean plasma activities of 0.8, 0.9, and 1.9 U/mL for CY216, NPS, and SPS, respectively. Twelve hours after injection, the antithrombotic effects of CY216 and NPS had totally vanished, whereas that of SPS was 68%. At that time, the plasma anti-Xa activities were less than 0.06 U/mL for CY216 and NPS, but 1.1 U/mL for SPS. For the latter compound, significant antithrombotic effects and detectable anti-Xa activities were still recorded 48 hours after the injection. The antithrombotic potency of the three compounds was also compared as their ability to inhibit the growth of a standardized venous thrombosis during 4 hours. The lowest total doses providing the maximum inhibitory effect were 3,125, 1,428, and 62 micrograms/kg for CY216, NPS, and SPS, respectively. These doses generated mean steady state antifactor Xa activities of 1.06, 1.5, and 1.2 anti-Xa U/mL, respectively. These observations indicate that the amplification mechanisms triggered by thrombin bound to fibrin and leading to the generation of new thrombin are essential to ensure venous thrombosis growth and that these mechanisms may be efficiently inhibited by pure antifactor Xa targeting agents.

Animals↗

PubMed1994

Fraxiparin, a low-molecular-weight heparin, stimulates megakaryocytopoiesis in vitro and in vivo in mice.

The effect of a low-molecular-weight heparin, faxiparin (Nadroparin), on murine megakaryocytopoiesis in vitro and in vivo was studied in comparison with unfractionated heparin. The addition of fraxiparin at 1-20 IU/ml into plasma clot cultures but not serum-free agar culture significantly enhanced MK colony growth. Furthermore, fraxiparin was found to potentiate the stimulating activity of aplastic anaemia serum (AAS) but not stem cell factor (SCF), interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF) and erythropoietin (Epo), on MK colony growth in vitro, and to neutralize the inhibitory effect of platelet factor 4 (PF4) in vitro and in vivo. Fraxiparin also acted synergistically with heparin cofactor II and antithrombin III to promote megakaryocyte colony formation. Intraperitoneal administration of fraxiparin twice daily for 4 d at 0.1-25 IU/injection increased in mice the level of blood platelet counts and the number of single MKs and CFU-MK in bone marrow. These data demonstrate that fraxiparin is able to positively regulate megakaryocytopoiesis.

Animals↗

PubMed1994

Heparin and low molecular weight heparins inhibit prothrombinase formation but not its activity in plasma.

Factor V activation is a critical step preceding prothrombinase formation. This study determined the contributions of factor Xa and thrombin, which activate purified factor V with similar catalytic efficiency, to plasma factor V activation during coagulation. Prothrombin activation began without a lag phase after a suspension of coagulant phospholipids, CaCl2, and factor Xa was added to factor X-depleted plasma. Hirudin, a potent thrombin inhibitor, abrogated prothrombin activation initiated with 0.5 and 1.0 nM factor Xa, but not with 5 nM factor Xa. In contrast, hirudin did not abrogate prothrombin activation in plasmas pre-incubated with 0.5, 1.0 or 5 nM alpha-thrombin for 10 s followed by the coagulant suspension containing 0.5 nM factor Xa. Thus, thrombin activates plasma factor V more efficiently than factor Xa. At concentrations which doubled the clotting time of contact-activated normal plasma, heparin and three low Mr heparins also abrogated prothrombin activation initiated with 0.5 nM factor Xa, but not with 5 nM factor Xa. If factor V in the factor X-depleted plasma was activated (by pre-incubation with 10 nM alpha-thrombin for 60 s) before adding 0.5, 1.0, or 5 nM factor Xa, neither hirudin nor the heparins altered the rates of prothrombin activation. Thus, none of the five anticoagulants inactivates prothrombinase. When 5 or 10 pM relipidated r-human tissue factor and CaCl2 were added to normal plasma, heparin and the three low Mr heparins delayed the onset of prothrombin activation until the concentration of factor Xa generated exceeded 1 nM, and they subsequently inhibited prothrombin activation to the same extent.(ABSTRACT TRUNCATED AT 250 WORDS)

Factor V↗

PubMed1994

Pharmacological properties of CY 216 and of its ACLM and BCLM components in the rabbit.

This study compares some in vivo pharmacological properties of CY 216 and of its ACLM and BCLM components having a molecular weight above and below 5.4 kDa respectively. The anti-factor Xa/antithrombin ratio of these compounds determined in a rabbit plasma system were 2.5 and 1.2 for CY 216 and ACLM respectively while BCLM was devoid of anti-thrombin effect. After bolus intravenous injection, continous infusion and subcutaneous administration, the clearances of anti-factor Xa activity generated by ACLM were, on the average, 2 and 1.5 times higher than those generated by BCLM and CY 216 respectively. The clearances of the anti-thrombin activity were comparable for CY216 and ACLM, and higher than those of the antifactor Xa activity. The duration of the antithrombotic effect was investigated in the Wessler model after a single subcutaneous injection of 1000 anti-factor Xa units of one of the compounds. Using thromboplastin as thrombogenic stimulus, the most efficient agent was ACLM and the antithrombotic activity was essentially correlated to the circulating anti-thrombin activity. Using human serum as thrombogenic stimulus, ACLM and BCLM were more efficient than CY 216 and the antithrombotic activity was mainly correlated to the anti-factor Xa activity. The ability of the 3 compounds to inhibit venous thrombosis growth was compared: they were found equipotent and the antithrombotic effect was independent of the anti-thrombin activity. The prohaemorrhagic properties were compared in the rabbit ear model. The activity of the 3 compounds were comparable and significantly less prohaemorrhagic than unfractionated heparin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Binding of heparin fractions to von Willebrand factor: effect of molecular weight and affinity for antithrombin III.

To investigate the influence of the structure of heparin on its binding to vWF, we compared heparin fractions of different molecular weight (MW) or affinity for antithrombin III (ATIII). We studied the interaction of purified 125I-vWF or plasma vWF, labeled with a pool of 125I-monoclonal antibodies to vWF, with unfractionated heparin immobilized on agarose beads. Fractions were compared as competitors of these interactions and their effect was quantitated by their half-maximal inhibition (IC50). When the MW of the fractions decreased, especially below 7500, their IC50 increased, indicating that the affinity of the fractions for vWF decreased with their MW. Using heparin-derived oligosaccharides, we also demonstrated that a minimal chain length of 18 monosaccharides was required for heparin binding to vWF. In addition, different fractions with low affinity for ATIII were compared as competitors of 125I-vWF binding to heparin-agarose. Despite a very low content of ATIII binding sites, some fractions retained a low IC50. Thus, heparin interaction with vWF is independent of the presence of the ATIII binding site and is mostly dependent on the length of the heparin chain. These data suggest that unfractionated heparin is a more potent inhibitor of vWF-dependent functions than low MW heparin fractions.

Antibodies, Monoclonal↗

PubMed1994

Low affinity heparin is an antithrombotic agent.

We have investigated the antithrombotic activities and haemorrhagic side effects of a low affinity heparin (LAH). In the rabbit thrombosis model using activated human serum as the thrombogenic challenge, the effect of LAH on 10' and 20' stasis was studied. At 10' stasis, 150 micrograms/kg of LAH reduced thrombus formation by 67% and total prevention was achieved at 500 micrograms/kg. At 20' stasis, 150 micrograms/kg was totally ineffective, 500 micrograms/kg was partially effective and 1000 micrograms/kg was required to achieve complete prevention of thrombosis. Mean peak circulatory level following infusion of 500 micrograms/kg of LAH was found to be 1.6 micrograms/ml by heparin cofactor II based assay and 0.13 iu/ml by anti-factor Xa assay. Thrombin generation tests of the same post injection samples showed an 80% reduction in thrombin production when compared with pre-injection samples. At 2.5 mg/kg, the mean bleeding time ratio (challenge:control) measured in the rabbit ear template model was 1.25 (cf saline control 0.88). Compared with results from previous studies on unfractionated heparin and dermatan sulphate, LAH is approximately 6 times less effective than UFH but 5 times more potent than dermatan sulphate. Since the mean bleeding time for UFH at 2.5 mg/kg was previously found to increase nearly two fold over the control value, LAH may present a lesser haemorrhagic risk than UFH. These data suggest that LAH is more effective in directly preventing venous thrombosis than dermatan sulphate. Although LAH is not as effective as UFH on a weight basis in the impairment of thrombogenesis, it may carry significantly lower bleeding risk.

Animals↗

PubMed1993

Preparation and anti-HIV activity of O-acylated heparin and dermatan sulfate derivatives with low anticoagulant effect.

In order to increase the ratio of anti-HIV activity to anticoagulant activity, glycosaminoglycan derivatives selectively substituted at OH and/or COOH groups were prepared. Standard heparin, heparin fragments, or dermatan sulfate were converted to their tributylammonium or tetrabutylammonium salts. Their selective O-acylation to various (controlled) degrees was carried out in a homogeneous way in N,N-dimethylformamide using carboxylic acid anhydrides and 4-(dimethylamino)pyridine as catalyst. Esterification of the COOH groups was performed by the addition of alkyl halide to an N,N-dimethylformamide solution of glycosaminoglycan tetrabutylammonium salts. The in vitro anticoagulant activity, the activity against HIV-1 and HIV-2 cytopathicity, the cytotoxicity, and the activity on the induction of giant cell formation were determined. O-acylation (O-butyrylation or O-hexanoylation) of the heparin fragments obtained by periodate depolymerization (compounds 2d and 2e), and their esters (compounds 7i and 7j), yielded products with very low anticoagulant effects in vitro, yet potent activity against both HIV-1 and HIV-2 induced cytopathicity, and low, if any, cytotoxicity. As compared to other anionic polysaccharides, these acylated derivatives are more active as inhibitors of HIV-induced giant-cell formation. Their anti-HIV activity is related to the degree of O-acylation and is mainly due to the inhibition of virus adsorption to the target cells.

Acylation↗

PubMed1993

Comparative inhibition of extrinsic and intrinsic thrombin generation by standard heparin, a low molecular weight heparin and the synthetic ATIII-binding pentasaccharide.

The inhibiting effect of standard heparin, CY216 and the ATIII-binding synthetic pentasaccharide on extrinsic and intrinsic thrombin generation were quantified by evaluating the decrease of the total amount of active thrombin appearing in plasma after triggering coagulation. Heparin as well as CY216 produced the same quantitative inhibition of extrinsic and intrinsic TGs whereas pentasaccharide inhibited more efficiently extrinsic TG. This pattern of inhibition was further confirmed on pure extrinsic or intrinsic coagulation respectively in factor IX- and factor VII-depleted plasmas. Furthermore, selective suppression of the anti-thrombin activity of CY216 by limited amounts of PF4 affected the intrinsic TG inhibition more markedly than the extrinsic one. It was concluded that anticoagulant activity produced mainly through thrombin scavenging leads to similar quantitative impairment of extrinsic and intrinsic coagulation, while selective ATIII-mediated factor Xa inhibition results in a more marked effect against the extrinsic system.

Amino Acid Sequence↗

PubMed1992

O-acylated heparin derivatives with low anticoagulant activity decrease proliferation and increase alpha-smooth muscle actin expression in cultured arterial smooth muscle cells.

Selectively O-acylated derivatives of various glycosaminoglycans were prepared and tested in vitro for their anticoagulant activity and their antiproliferative effect on rat and rabbit smooth muscle cells. When O-acylation (butyrylation or hexanoylation) had been performed on periodate-depolymerized heparin fragments having very low anticoagulant activity, the antiproliferative potency was markedly increased (IC50 = 2 and 1 micrograms/ml respectively, versus 31 micrograms/ml for starting compound) without an increase in anticoagulant activity. The antiproliferative activity was related to the degree of acylation. The O-acylated derivatives of heparin fragments were also very active in reversing the de-differentiation of smooth muscle cell in culture, as estimated by the increase in the expression of alpha-smooth muscle actin and alpha-smooth muscle actin mRNA.

Actins↗

PubMed1992

Influence of molecular weight upon the anticoagulant and pharmacokinetic properties of dermatan sulfate in the rabbit.

In order to improve the pharmacokinetic properties of unfractionated dermatan sulfate (UDS, mean MW: 25kD), the disposition of 4 low molecular weight dermatan sulfates (LMWDS) with a mean MW ranging from 15 to 4 kD was investigated in the rabbit. In comparison with UDS, it was established that after intravenous administration, the half-life of disappearance, the distribution volume and the clearance of the biological activity increased as the mean molecular weight decreased. After subcutaneous administration, the bioavailability of the 4 LMWDS was improved in comparison with that of UDS, but large inter-animal variations were recorded for LMWDS having a mean MW over 9 kD. Therefore the best compromise between biological activity, clearance, half-life of disappearance, bioavailability and reproducibility after subcutaneous administration should be a compound having a MW ranging from 4 to 9 kD.

Animals↗

PubMed1992

Pharmacodynamic properties of long lasting butyryl heparin derivatives in the rabbit.

This paper reports on the pharmacodynamic properties of butyryl derivatives of unfractionated heparin (C4-UH) and of low molecular weight heparin (C4-CY 216) after bolus intravenous injection, constant infusion and subcutaneous administration to rabbits. The pharmacodynamic properties of the two butyryl derivatives were compared to those of the parent compounds, unfractionated heparin (UH) and low molecular weight heparin (CY 216). After bolus intravenous injection of increasing doses, the disposition of the butyryl derivatives were comparable to that of their parent compounds up to 3 mg kg-1. Over this dose, their clearances became 2 to 3 times lower. These long lasting properties were confirmed by constant intravenous infusion experiments. After subcutaneous administration, the bioavailability of C4-UH remained low (10%) at any dose while that of C4-CY 216 ranged from 42 to 120%. If these findings are confirmed in man, these new derivatives open the possibility of treating established deep vein thrombosis with only one daily injection of a butyryl derivative of low molecular weight heparin.

Animals↗

PubMed1992

Pharmacological properties of a low molecular weight butyryl heparin derivative (C4-CY 216) with long lasting effects.

We have investigated the pharmacological properties of an O-acetylated butyryl derivative of the low molecular weight heparin CY 216 (C4-CY 216). In a purified system the ability of C4-CY 216 to catalyze thrombin and factor Xa inhibition was comparable to that of CY 216. The antithrombin and antifactor Xa catalytic efficiencies of C4-CY 216 were reduced 217 and 12 times respectively when albumin (10 mg ml-1) was added to the reagents, while those of CY 216 were essentially unchanged. In plasma, the antifactor Xa specific activity of C4-CY 216 was close to that of CY 216 but the antithrombin specific activity was 2 times lower. After bolus and continuous intravenous injection to rabbits, the clearances of the two activities of C4-CY 216 were on average half the corresponding values of CY 216. After subcutaneous injection, the bioavailability of C4-CY 216 was comparable to that of CY 216. C4-CY 216 was as potent as CY 216 in preventing venous thrombosis in the thromboplastin-Wessler model and the duration of the antithrombotic effect was longer than that of the parent compound. The chemical alteration of CY 216 did not enhance the prohaemorrhagic effect in the rat tail transection model. Therefore, the new concept of heparin derivative having a low clearance and long lasting effects that we have recently reported for unfractionated heparin may also be applied to a low molecular weight heparin.

Animals↗

PubMed1992

The mode of action of CY216 and CY222 in plasma.

Three fractions of the low molecular weight heparin CY216 (fraxiparin, mean molecular weight [MMW] 5,090), with MMWs of respectively, 3,090, 4,400 and 7,910 were prepared by gel permeation chromatography. From CY222 (MMW 3,770) as well as from CY216 and its three fractions the material with high affinity to antithrombin III (AT III) was obtained by chromatography on immobilised AT III. The molecular weight distribution of each of the ten preparations thus obtained was determined by high performance liquid chromatography, while the content of AT III binding material was determined by stoichiometric titration of AT III, monitored by intrinsic fluorescence enhancement. We measured the effect of all heparins on the decay of endogenous thrombin in plasma and on the overall generation of thrombin in plasma, triggered via the extrinsic or via the intrinsic pathway. From these data we calculated the time course of prothrombin conversion, i.e. the course of factor Xa activity as expressed by prothrombinase activity. It was found that in platelet-poor plasma the anticoagulant properties of the heparins are largely dependent on their antithrombin action, which is determined by their content of high affinity material with a MW of 5,400 or higher. The specific antithrombin activity of all heparins, when expressed in terms of material with high affinity to antithrombin III (HAM) with a MW greater than 5,400 is 13.0 min-1/(microgram/ml) (range 10.5-15.9).(ABSTRACT TRUNCATED AT 250 WORDS)

Antithrombin III↗

PubMed1992

Antithrombotic activity, bleeding effect and pharmacodynamics of a succinyl derivative of dermatan sulphate in rabbits.

This paper compares the pharmacological properties of a new succinyl dermatan sulphate derivative (Suc-DS) to those of the natural dermatan sulphate (DS). Suc-DS was on average 2-3 times more potent than DS in catalysing the inhibition of thrombin by heparin cofactor II and in prolonging the activated partial thromboplastin time and the thrombin clotting time. After bolus injection, Suc-DS was also 2-3 times more potent than DS to prevent experimental venous thrombosis in a Wessler model. Thromboplastin or human serum were used as the thrombogenic stimulus. In contrast, the bleeding effect assessed by rat tail transection technique was comparable. After bolus intravenous injection, the pharmacodynamics of Suc-DS indicated a lower volume of distribution, which was close to the plasma volume, and a slightly lower clearance of elimination. Therefore this chemical alteration of natural DS yields a new compound with an improved antithrombotic benefit/haemorrhagic risk ratio.

Animals↗