Heparin-associated thrombocytopenia. In vitro effects of different molecular weight heparin fractions

Mg, Huisse; Mc, Guillin; Bezeaud, Annie; Toulemonde, F; Kitzis, M; Andréassian, B

doi:10.1016/0049-3848(82)90066-4

Cited by 42 publications

(18 citation statements)

References 11 publications

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“…However, heparin is a highly heterogeneous substance with many biological effects (32). Low molecular weight fractions of heparin show a reduced tendency to cause hemorrhage and thrombopoenia (34), but there is clearly a need for more specific, versatile, and less toxic anticoagulant drugs.…”

Section: Resultsmentioning

confidence: 99%

“…Hirudin clones were identified by screening with a long synthetic oligonucleotide (16), the design of which was based upon the published amino acid sequence ofhirudin (8,9) and on codon usage data from insects, the closest evolutionary relatives of segmented worms for which extensive sequence data were available. A 48-mer (5' CTGAGGCTTAGGAGTACCCTGGCCGGTGACGCACTG-GTTCTTCTCGCC 3') was synthesized, corresponding to amino acids [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] of the hirudin sequence (4).…”

Section: Resultsmentioning

confidence: 99%

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Cloning and expression of a cDNA coding for the anticoagulant hirudin from the bloodsucking leech, Hirudo medicinalis.

Harvey¹,

Degryse²,

Stefani³

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

191

102

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Cloned cDNAs have been isolated that encode a variant of hirudin, a potent thrombin inhibitor that is secreted by the salivary glands of the medicinal leech, Hirudo medicinals. This variant probably corresponds to a form that has been purified from leech heads but differs in amino acid sequence from the hirudin purified from whole leeches. There are at least three hirudin transcripts detectable in leech RNAs that are different in size, site of synthesis, inducibility by starvation, and relationship to hirudin activity. The new hirudin variant predicted by the cDNA and the heterodisperse transcription products suggest a hirudin protein family. The hirudin cDNA was expressed in Esckerichia coli under the control of the bacteriophage X PL promoter. The recombinant product is biologically active, inhibiting the cleavage by thrombin of fibrinogen and a synthetic tripeptide substrate.Leech hirudin is the most potent natural inhibitor of coagulation known (1-4). A very stable noncovalent 1:1 complex is rapidly and specifically formed with a-thrombin, thereby abolishing its ability to cleave fibrinogen (4). To date there is no evidence that it can interact with other components of the human coagulation cascade (5, 6).Hirudin is a polypeptide of 65 amino acids that is stable to extremes of pH and heat (4). It contains six cysteine residues grouped in the NH2-terminal half of the protein, an acidic COOH-terminal half, and one sulfated tyrosine (7). A hirudin form with isoleucine at the NH2 terminus was first purified from leech heads (H. medicinalis) (4, 8) in which activity was found to be concentrated in the salivary glands. Subsequently, Bagdy et al. (9) adopted new purification schemes using whole leeches instead of heads, yielding a form with Val-Val as the first two NH2-terminal amino acids. The amino acid sequence of the "whole body form" has been determined by independent groups (8, 10), and valine residues at positions 1 and 2 have been confirmed. Both forms had a specific activity of around 8000-10,000 antithrombin units/mg. However, more recently, Baskova et al. (11) Hirudin Activity. Antithrombin activity in leech or bacterial extracts was measured in a clotting assay (4) using citrated human platelet-poor plasma as a fibrinogen source or in a colorimetric assay using the thrombin chromogenic substrate Tos-Gly-Pro-Arg-p-nitroanilide (Chromozym TH, Boehringer Mannheim; Tos = tosyl) (7). Standard curves Abbreviation: kb, kilobases. tPresent address:

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Cloning and expression of a cDNA coding for the anticoagulant hirudin from the bloodsucking leech, Hirudo medicinalis.

Harvey¹,

Degryse²,

Stefani³

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

191

102

View full text Add to dashboard Cite

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“…In all cases, the presence of a heparin-dependent platelet aggregating factor was demonstrated in pa tients' platelet-poor plasma. In the 2 cases in which plasma fractionation was performed, the platelet-aggregating activity was shown to be carried by IgG as it is most frequently observed [9,18,19]. Two types of heparininduced thrombocytopenia have been re ported [20].…”

Section: Discussionmentioning

confidence: 99%

“…Huisse et al [9] have shown that only high molecular weight heparin fractions promoted platelet aggregation in the pres ence of plasma from 5 patients with HIT, whereas LMWH fractions (< 5,000 daltons) failed to induce aggregation in the presence of the same patient's plasma. Bell and Royall [4] have shown that the incidence of throm bocytopenia is related to the source of hepa rin with a much higher incidence with bo vine lung heparin than with intestinal mu cosa heparin.…”

Section: Discussionmentioning

confidence: 99%

“…Oral antico agulation with or without antiaggregating agents has been used [8], but the time taken to achieve full anticoagulation by use of vita min K antagonists is long and the effective ness of antiaggregating agents in these pa tients is questionable. Recently, Huisse et al [9] have shown that the platelet-aggregating factor present in the plasma from patients with HIT pro moted in vitro platelet aggregation only in the presence of high molecular weight heparin fractions whereas heparin fractions with mo lecular weight less than 5,000 daltons failed to induce the phenomenon. Successful treat ment of some patients with low molecular weight heparin (LMWH) fractions has been reported [10][11][12][13][14] whereas Horellou et al [15] pointed out the risk of persistence of throm bocytopenia with such treatment [15].…”

Section: Introductionmentioning

confidence: 99%

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Low Molecular Weight Heparin Fractions as an Alternative Therapy in Heparin-induced Thrombocytopenia

Gouault-Heilmann¹,

Huet

Adnot

et al. 1987

Pathophysiol Haemos Thromb

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Eight patients with a delayed-onset heparin-induced thrombocytopenia, with thrombotic complications requiring immediate anticoagulation in 7 of them, were given low molecular weight heparin (LMWH) fractions as alternative therapy. This treatment led to normalization of platelet count within 3–5 days in 6 patients with clinical recovery in 5. In 2 patients, thrombocytopenia persisted despite LMWH therapy. In vitro platelet aggregation tests performed in all patients gave evidence of a relationship between the presence (or absence) of a LMWH-dependent platelet-aggregating factor in the patients’ plasma and the persistence (or correction) of the thrombocytopenia with LMWH therapy. Although positive in vitro tests may not necessarily be associated with thrombocytopenia, in vitro testing may prove to be a useful guide before giving LMWH fractions as an alternative therapy in patients with heparin-induced thrombocytopenia requiring immediate anticoagulation.

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Anwendung von niedermolekularem Heparin bei Hämodialysepatienten

et al. 1985

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Low-molecular-weight (LMW) heparin has been compared to standard unfractionated (UF) heparin in a total of 49 patients on hemodialysis and hemofiltration in order to determine the necessary therapeutic dose and its effect on the coagulation system. A LMW heparin dose corresponding to 50% of the normal UF heparin dose was found to produce similar plasma heparin levels (anti-FXa-U/ml) in particular on minimal heparinization. At higher doses, UF heparin produced a more marked increase in plasma-heparin than did LMW heparin. Highly significant differences were found between UF and LMW heparin in their effects on PTT and thrombin time. Partial thromboplastin time (PTT) increased under UF heparin by an average of 120 s whereas LMW heparin only produced an increase of 5-7 s. Thrombin time was increased by 250-280 s under UF heparin and by 5-8 s under LMW heparin. With this LMW heparin dose of 50% of the UF heparin dose, no thrombosis of the extracorporal system occurred and no macroscopic detectable thrombotic material was found in the dialyzers or filters. No significant differences were observed between the effects of UF and LMW heparin on Factor VIII activity and fibrin monomers, so that a difference in coagulation activation between the two heparins can be excluded. Furthermore, there were no changes in thromboplastin time according to Quick, fibrinogen, antithrombin III, plasminogen, and a2-antiplasmin.(ABSTRACT TRUNCATED AT 250 WORDS)

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Heparin-associated thrombocytopenia. In vitro effects of different molecular weight heparin fractions

Cited by 42 publications

References 11 publications

Cloning and expression of a cDNA coding for the anticoagulant hirudin from the bloodsucking leech, Hirudo medicinalis.

Cloning and expression of a cDNA coding for the anticoagulant hirudin from the bloodsucking leech, Hirudo medicinalis.

Low Molecular Weight Heparin Fractions as an Alternative Therapy in Heparin-induced Thrombocytopenia

Anwendung von niedermolekularem Heparin bei Hämodialysepatienten

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