| 31. |
- Karpman, D, et al.
(författare)
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Platelet activation in hemolytic uremic syndrome
- 2006
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Ingår i: Seminars in Thrombosis and Hemostasis. - : Georg Thieme Verlag. - 0094-6176 .- 1098-9064. ; 32:2, s. 128-145
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Tidskriftsartikel (refereegranskat)abstract
- Platelet consumption in platelet-fibrin aggregates leading to thrombocytopenia and small vessel obstruction are major features of the hemolytic uremic syndrome (HUS). Although thrombocytopenia has been correlated to poor prognosis, the mechanisms by which thrombocytopenia develops in HUS have not been completely elucidated. However, plausible explanations have been platelet contact with thrombogenic surfaces and/or direct contact with an aggregating agent. This article summarizes several mechanisms of platelet activation, interactions with leukocytes, chemokine release, complement activation, and antimicrobial defense. Specific mechanisms are outlined by which platelets may be activated, leading to thrombocytopenia during HUS. In diarrhea-associated HUS Shiga toxin has been shown to injure the endothelium, thus exposing the subendothelium, releasing tissue factor, and rendering the vessel wall prothrombotic. Shiga toxin also binds to and activates platelets. The toxin may activate endothelial cells and platelets simultaneously. In atypical HUS the alternative complement pathway is activated because of mutations in complement regulatory proteins. Mutated factor H does not bind to endothelium and platelets efficiently, enabling complement activation on these cells. In thrombotic thrombocytopenic purpura, intravascular platelet clotting Occurs due to dysfunction of the von Willebrand factor (VWF)-cleaving protease ADAMTS13. Thrombi are formed by binding of platelets to ultralarge VWF multimers.
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| 32. |
- Karpman, Diana, et al.
(författare)
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Platelet activation in hemolytic uremic syndrome.
- 2006
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Ingår i: Seminars in Thrombosis and Hemostasis. - : Georg Thieme Verlag. - 1098-9064 .- 0094-6176. ; 32:2, s. 128-145
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Forskningsöversikt (refereegranskat)
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| 33. |
- Lassila, Riitta, et al.
(författare)
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Nordic Haemophilia Council's Practical Guidelines on Diagnosis and Management of von Willebrand Disease
- 2011
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Ingår i: Seminars in Thrombosis and Hemostasis. - : Georg Thieme Verlag. - 1098-9064 .- 0094-6176. ; 37:5, s. 495-502
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Tidskriftsartikel (refereegranskat)abstract
- von Willebrand disease (VWD) is the most common inherited bleeding disorder characterized by spontaneous or tissue injury related, mostly mucocutaneous, bleeding events. VWD affects both males and females and is caused by quantitative or qualitative deficiency of von Willebrand factor. The diagnostic procedure is complicated because VWD is highly heterogeneous, and differential diagnosis from platelet disorders may be challenging. Moreover, these defects may even coexist, impacting the bleeding phenotype. Mild and moderate VWD can be difficult to distinguish from the normal population, and VWD subtyping may also be problematic. This article summarizes the guidelines of the Nordic Haemophilia Council (NHC), which are intended to serve as a practical tool and provide the standards for diagnosing and treating VWD patients. The complete Nordic Guidelines on VWD are available at the NHC Web site (http://nordhemophilia.org).
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| 34. |
- Lassila, Riitta, et al.
(författare)
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Practical Viewpoints on the Diagnosis and Management of Heparin-Induced Thrombocytopenia
- 2011
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Ingår i: Seminars in Thrombosis and Hemostasis. - : Georg Thieme Verlag. - 1098-9064 .- 0094-6176. ; 37:3, s. 328-335
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Tidskriftsartikel (refereegranskat)abstract
- Heparin-induced thrombocytopenia (HIT, type II) is an immune-mediated disorder due to antibodies formed against heparin platelet factor 4 complexes, usually appearing at days 5 to 14 after initiation of heparin. It is important to recognize HIT because heparin prophylaxis or treatment paradoxically associates with new venous and/or arterial thrombosis. Early clinical suspicion and diagnosis together with proper pharmacotherapy and close laboratory monitoring are the cornerstones for successful management. This includes monitoring of Thrombocytopenia, its Timing to heparin administration, appearance of new Thrombosis or resistance to treatment, and differential diagnosis by exclusion of oTher causes (the 4T's). Specific attention should be paid to the absence or presence of thrombosis and to tailoring thromboprophylaxis or anticoagulant therapy with a nonheparin alternative. Even in the absence of HIT-associated thrombosis, an active policy for prolonged thromboprophylaxis is demanded. Rapid and reliable assays should be developed for diagnosis and anticoagulation monitoring to secure safe management with nonheparins. Semiquantitative testing for on-call hours should be available and later confirmed as clinically needed. Alternative therapeutic options are available, but because their use is infrequent, experienced coagulation treatment centers should provide guidance in the treatment and in laboratory monitoring. Most of the evidence in HIT is grade IC, and thus the best evidence is provided by clinical experience. New anticoagulants and platelet inhibitors may offer future alternatives in the management of HIT, but the current treatment options provide the best experience and benefit. The joint clinical and laboratory guidelines provided in this article along with two practical case scenarios were prepared by a Nordic expert panel. They will be valuable for hematologists and colleagues who do not routinely encounter HIT.
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| 35. |
- Lee, Christine A., et al.
(författare)
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Inhibitor development in hemophiliacs: The roles of genetic versus environmental factors
- 2006
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Ingår i: Seminars in Thrombosis and Hemostasis. - : Georg Thieme Verlag. - 1098-9064 .- 0094-6176. ; 32, s. 41561-41561
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Tidskriftsartikel (refereegranskat)abstract
- Approximately 5 to 7% of patients with hemophilia A have inhibitory antibodies to factor (F) VIII, which increases to similar to 13% in patients with severe disease. The strongest determinant of the risk of inhibitor development identified is the type of mutation in the FVIII gene that gives rise to the disease. However, accumulating evidence clearly indicates that other genetic factors (e.g., major histocompatibility complex alleles and other immune-modulatory genes) and factors associated with treatment (e.g., type of FVIII concentrate, route of administration, and age of first exposure) may also influence the risk of inhibitor development. There is much interest in identifying such genetic and treatment-related factors to help minimize the risk of inhibitor development and improve treatment outcomes.
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| 36. |
- Lethagen, Stefan
(författare)
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Desmopressin in mild hemophilia A: indications, limitations, efficacy, and safety.
- 2003
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Ingår i: Seminars in Thrombosis and Hemostasis. - : Georg Thieme Verlag. - 1098-9064 .- 0094-6176. ; 29:1, s. 101-105
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Tidskriftsartikel (refereegranskat)abstract
- Replacement therapy with blood products has long been the only available therapeutic option for patients with bleeding disorders. Plasma-derived cryoprecipitate and factor (F) VIII concentrates, which have been used for hemophilia A patients, involve the risk of transmitting blood-borne diseases. Both plasma-derived and recombinant FVIII concentrates are expensive, and there is a global shortage. The synthetic vasopressin analogue desmopressin acetate (1-deamino-[8-D-arginine]-vasopressin, DDAVP) increases plasma concentrations of coagulation FVIII and von Willebrand factor (vWF) two fold to six fold through endogenous release. The drug is an attractive therapeutic alternative because it carries no risk of transmission of infectious diseases. Desmopressin is today a widely used hemostatic agent not only in patients with mild hemophilia A or von Willebrand disease (vWD) but also in those with congenital or acquired platelet dysfunction. There is a long clinical experience with the drug because it has been used for prevention of bleedings in connection with invasive procedures and for treatment of bleedings since the mid-1970s. Not all hemophilia A patients can be treated. The clinical usefulness depends on the postdesmopressin plasma concentration of FVIII, which in turn depends on the patient's basal FVIII level. Therefore, a test dose is recommended in candidate patients. In general, only the mildest hemophilia A patients respond sufficiently. Optimal hemostatic effect is achieved with a dosage of 0.3 μg/kg given intravenously. An intranasal desmopressin spray is suitable for the home treatment.
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| 37. |
- Ljung, Rolf, et al.
(författare)
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Genetic counselling of haemophilia carriers
- 2003
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Ingår i: Seminars in Thrombosis and Hemostasis. - : Georg Thieme Verlag. - 1098-9064 .- 0094-6176. ; 29:1, s. 31-36
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Tidskriftsartikel (refereegranskat)abstract
- Basic analysis of a potential carrier includes calculation of the probability, or odds, for carriership based on pedigree and clotting factor analysis. Genotype assessment constitutes a more accurate method of carrier detection. Where circumstances permit, the genetic diagnosis of hemophilia should be based on the direct identification of the pathogenic mutation in the factor (F) VIII gene. Neutral mutations in the FVIII gene and the risk of mosaicism (a mixture of normal and mutation carrying cells) in sporadic families may cause misclassification. If it is not possible to use the mutation for diagnostic purposes, it may be possible to use linked polymorphic markers (restriction fragment length polymorphisms [RFLP]) to trace the inheritance of the hemophilia gene within a pedigree. Linkage analysis is limited because of uninformative patterns of polymorphic markers, ethnic variation, linkage disequilibrium, and the need for participation of family members, and it is not useful in sporadic families, which constitute more than half of the hemophilia families. Potential carriers of hemophilia should be offered qualified assistance in genetic information, testing, and counseling to help them to cope with the psychological and ethical problems related to carriership of a genetic disorder.
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| 38. |
- Lubenow, Norbert, et al.
(författare)
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Hirudin in heparin-induced thrombocytopenia.
- 2002
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Ingår i: Seminars in Thrombosis and Hemostasis. - : Georg Thieme Verlag KG. - 0094-6176 .- 1098-9064. ; 28:5, s. 431-8
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Tidskriftsartikel (refereegranskat)abstract
- Heparin-induced thrombocytopenia (HIT), a serious side effect of heparin treatment, requires alternative anticoagulation in most affected patients. The recombinant hirudin (r-hirudin) lepirudin has been approved for this purpose after two prospective trials in laboratory-confirmed HIT patients. Other drugs available for this purpose are danaparoid sodium (a heparinoid) and argatroban, a synthetic direct thrombin inhibitor. In this article, recommendations for optimal use of r-hirudin in HIT are given, covering therapy in uncomplicated patients as well as in special situations such as heparin reexposure of HIT patients. Because lepirudin's half-life depends on renal function, it may vary between 1 and 200 hours, which requires individual dose adjustments. Lepirudin compares favorably with danaparoid, based on retrospective data. No direct comparisons of lepirudin with argatroban are available, but argatroban might offer advantages in patients with renal failure, because it is mainly eliminated hepatically. Major hemorrhage, the main risk of lepirudin treatment, occurring in about 15% of patients, makes close monitoring important. New monitoring tools, such as the ecarin clotting time (ECT), might further reduce bleeding risks. Antihirudin antibodies, which can alter the pharmacokinetics as well as the pharmacodynamics of hirudin, can also be countered by close monitoring and appropriate dose adjustments. Whereas hirudins have not yet managed to gain importance in non-HIT indications such as unstable coronary syndromes, they have a major role to play in the treatment of HIT. The choice between the available drugs for HIT, namely lepirudin, danaparoid, and argatroban, has to be made according to the clinical presentation of the patient.
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| 39. |
- Maas, C, et al.
(författare)
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The plasma contact system 2.0
- 2011
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Ingår i: Seminars in thrombosis and hemostasis. - : Georg Thieme Verlag KG. - 1098-9064 .- 0094-6176. ; 37:4, s. 375-381
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Tidskriftsartikel (refereegranskat)
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| 40. |
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