PubMed Health⌕ Search

Biomedical subjects

M von Depka

Publications and source records attributed to M von Depka.

13 recordsLinked to original sources
PubMed2006

Current European practice in immune tolerance induction therapy in patients with haemophilia and inhibitors.

The management of patients with inhibitors is an important challenge in haemophilia care. The lack of randomized controlled trials means that clinical decisions are generally based on subjective opinions, and purchasers' attention is likely to focus on the costs of treatment. In order to assess the current management of inhibitor patients and use of immune tolerance induction therapy (ITI) in Europe, we performed a survey within a European network of 21 comprehensive care centres from 14 countries (the European Haemophilia Therapy Standardisation Board). The survey identified a total of 381 patients with inhibitors attending the centres, 211 (55.4%) of whom had never been exposed to ITI. Between 1998 and 2003, the centres performed 233 procedures and 114 (48.9%) were successful. The survey demonstrated that dosing, which is the time to start and stop the ITI, the type of concentrate to use and the definition of success varied among the centres. Well-designed trials are warranted to guide decision-making, but in the absence of these studies we have developed consensus guidance for the management of inhibitor patients based on current clinical practice, as identified by the survey, and review of the literature.

Adult↗
PubMed2006

[Possibilities and limitations of thrombelastometry/-graphy].

Thrombelastometry/-graphy provides information about clot strength and stability. Modified thrombelastometry/-graphy improved standardisation and diagnostic information using this system. Heparinase modified thrombelastometry/-graphy allows estimation of heparin. The introduction of FIBTEM on the ROTEM first allows a clear estimation of the plasmatic and the platelet component of clot strength, which may be of interest in managing haemostasis in perioperative setting. In this context the meaning of fibrinogen should be evaluated. As our clinical data show there is no predictive value of elevated D-dimers to hyperfibrinolysis in perioperative setting. However, thrombelastometry/-graphy do not deteckt disturbances in primary haemostasis such as von Willebrand Syndrom. The effect of acetylsalicylacid and clopidogrel do not have any influence on thrombelastometry/-graphy, as well. GPIIb/IIIa-Antagonists such as ReoPro may reduce clot strength at high dosis. A similar effect may be expected in severe M. Glanzmann. The correlation between coagulation time in thrombelastometry/-graphy (CT/r-value) to conventional coagulation may be low because of different activators used. The introduction of rotationthrombelastometry (ROTEM) provides a stable system suitable for bedside-monitoring.

Blood Coagulation↗
PubMed2005

Managing acute bleeds in the patient with haemophilia and inhibitors: options, efficacy and safety.

The options available for treating the patient with haemophilia and inhibitors undergoing surgery or with other acute bleeds include high-dose factor VIII (FVIII) (human or porcine), prothrombin complex concentrates (PCCs), activated PCCs (aPCCs), recombinant activated factor VII (rFVIIa), and factor replacement combined with immunoadsorption or immunosuppression. Human FVIII is effective in patients with low-titre inhibitors. Porcine FVIII is currently not available, and PCCs and aPCCs, although effective, have been associated with a high incidence of adverse events. Immunoadsorption and immunosuppression offer excellent long-term solutions, but the duration of these techniques makes them less attractive for use in acute settings. Recombinant FVIIa has demonstrated excellent efficacy and safety, even in patients refractory to other therapies.

Acute Disease↗
PubMed2005

Inhibitor development in patients with hemophilia A after continuous infusion of FVIII concentrates.

Continuous infusion (CI) of coagulation factor concentrates has been used since the early 1990s. Recent reports of the occurrence of an inhibitor after CI have raised concerns about this method of treatment. We conducted a retrospective study to investigate the development of inhibitors after CI of Factor VIII concentrates in Germany. So far, 13 hemophilia centers have been contacted, and data have been collected by a questionnaire. Of the 13 centers, CI had never been performed in three, no inhibitors had been detected in five, and inhibitor development after CI was recorded in 10 patients in the remaining five centers. Of these 10 patients (ages 7 months to 57 years), five were suffering from severe, one from moderate, and four from mild hemophilia. Indications for treatment were major bleeds and surgical procedures. Plasma-derived (6 cases) and recombinant (4 cases) factor concentrates were given in various infusion sets. Data concerning amount infused (4300 to > 100,000 IU), number of days of exposure to factor concentrates (1 to > 100), and inhibitor characteristics (alloantibodies, 3 LR, 7 HR) were collected. Regarding hemophilia genotype, we found missense mutations in four patients, intron-22 inversions in two, and one small deletion in one; the genotype in three was unknown. In conclusion, only 3 out of 10 patients who developed an inhibitor after CI showed the typical risk profile for inhibitor formation, which is severe hemophilia A with a severe gene defect and less than 50 days of exposure to coagulation factor concentrates. Especially striking was the finding that 50% of the patients who developed inhibitors had mild to moderate hemophilia A. Our data point to the existence of a so-far unknown factor, related to CI, that might lead to inhibitor formation.

Adult↗
PubMed2003

Recombinant factor VIII expression in hematopoietic cells following lentiviral transduction.

Autologous transplantation of gene-modified hematopoietic stem cells may provide a therapeutic strategy for several monogeneic disorders. In previous studies, retroviral gene transfer of coagulation factor VIII (FVIII) into FVIII(-/-) mouse bone marrow (BM) cells did not result in detectable plasma FVIII levels. However, specific immune tolerance was achieved against neo-antigenic FVIII. Here, we used lentiviral vectors to study the ability of various hematopoietic cell types to synthesize and secrete recombinant FVIII. Several myeloid, monocytic and megakaryocytic cell lines (K-562, TF-1, Monomac-1, Mutz-3, Meg-01) expressed FVIII at 2-12 mU/10(4) cells. In contrast, two lymphatic cell lines, BV-173 and Molt-4, were less-efficiently transduced and did not express detectable FVIII. Similarly, peripheral blood-derived primary monocytes were transduced efficiently and expressed up to 20 mU/10(4) cells, whereas primary lymphocytes did not express FVIII. Although human and canine CD34(+) cells were transduced efficiently, the cells expressed very low levels of FVIII (up to 0.8 mU/10(4) cells). Following xenotransplantation of transduced CD34(+) into NOD/SCID mice, ELISA failed to detect FVIII in the plasma of engrafted mice. However, NOD/SCID repopulating cell (SRC)-derived human monocytes isolated from BM of these mice secreted functional recombinant FVIII after culture ex vivo. Again, SRC-derived human lymphocytes did not secrete FVIII. Therefore, certain hematopoietic cell types are able to synthesize and secrete functional recombinant FVIII. Our results show for the first time that transplantation of transduced CD34(+) progenitors may give rise to differentiated hematopoietic cells secreting a nonhematopoietic recombinant protein.

Animals↗
PubMed2003

The ex-vivo-shunt-model: novel approach for assessing the thrombogenicity of vascular implants.

OBJECTIVE: Disadvantages associated with commercially available vascular implants necessitate alternative strategies to develop new vascular prostheses. Although many tissue characterizing strategies have been defined, no valid test for thrombogenicity exists. Here we introduce a novel concept for thrombogenicity testing of vascular implants METHODS: Silastic tubes were implanted into the carotid arteries of 12 sheep. After placing these shunts, tc99m-labeled platelets were administered and test-vessels were put in between the shunts. Native autologous (n=6), as well as native/acellularized allogeneic (n=6/n=6), and xenogeneic (n=6/n=6) carotid arteries and allogeneic (n=6/n=6) and xenogeneic (n=6/n=6) carotid arteries reseeded with allogeneic endothelial-cells, fibroblasts and myocytes were evaluated. Number and time course of intra-operatively deposited platelets were evaluated with a Geiger-counter; certain areas of platelet deposition located, envisioned and characterized by a gamma-camera and scanning electron-microscopy afterwards. RESULTS: Counter results revealed no significant different platelet depositions when comparing silastic tubes with either autologous or allogeneic native carotid arteries. However, starting 5 minutes after placement, acellularized/reseeded allogeneic (p=0.001/p=0.00004), and xenogeneic (p=0.0001/p=0.01) carotid arteries showed significantly more platelet depositions than native autologous carotides. Moreover, it was possible to show that almost no platelets adhere to native vessels or silastic tubes, thus proving the test method itself. CONCLUSION: The Ex-Vivo-Shunt-Model is a valid method to measure and envision the intrinsic thrombogenicity of vascular implants.

Anastomosis, Surgical↗
PubMed2001

Use of recombinant factor VIIa (NovoSeven) in patients with Glanzmann thrombasthenia.

Recombinant factor VIIa (rFVIIa; NovoSeven, Novo Nordisk, Bagsvaerd, Denmark) appears effective and relatively safe for the treatment of bleeding and for surgical prophylaxis in patients with Glanzmann thrombasthenia as reported to the International Registry on rFVIIa and Congenital Platelet Disorders. One of the shortcomings of the Registry data is the heterogeneity of treatment protocol, including dosage, number of doses used, duration of treatment before declaration of failure, and mode of rFVIIa administration (bolus v continuous infusion). The data are not yet sufficient to define optimal regimens for various indications such as the type of bleeding or the type of procedures. The place of this drug compared to platelet transfusion in the overall management of patients with Glanzmann thrombasthenia will need to be determined in relationship to a number of challenges and unresolved issues in the clinical care of these patients. These issues include: how to improve local measures for patients with mucosal bleeds, optimal management of young women during menarche, optimal platelet transfusion regimens for various indications, the relationship between antiplatelet antibodies detected by monoclonal antibody-specific immobilization of platelet antigens (MAIPA) and effectiveness of platelet transfusion, whether there are other biological tests that may correlate with effectiveness of platelet transfusion, and management of pregnancy and delivery regarding antiplatelet immunization.

Coagulants↗
PubMed2001

Autoimmune hepatitis associated with coagulation disorders and immunethyreopathy.

We present the case of a 42-year-old female patient with the diagnoses of autoimmune hepatitis type I and autoimmune thyroiditis. Furthermore this patient had an unusual combination of coagulation disorders with homozygous Factor V Leiden mutation (APC resistance) and presence of antiphospholipid antibodies, leading to deep vein thromboses and miscarriages. Only few cases with the combination of autoimmune hepatitis and antiphospholipid antibodies have been described and almost all of them had become symptomatic with the antiphospholipid syndrome. As both autoimmune phenomenons furthermore share similar HLA-patterns, their coincidence is probably not as uncommon as the limited number of case reports suggests. Therefore attention in patients with autoimmune hepatitis should be focused on thrombophilia.

Activated Protein C Resistance↗
PubMed2001

Tissue factor and thrombomodulin levels are correlated with stage of cirrhosis in patients with liver disease.

Liver cirrhosis is associated with alterations of the coagulation system commonly causing bleeding as well as thromboembolic complications. The potential pathophysiological roles of tissue factor (TF) (the initiator of the extrinsic coagulation pathway) and thrombomodulin (TM) (an initiator of the anticoagulatory protein C pathway) are unknown. We therefore measured plasma concentrations of TF and TM in 111 patients with liver diseases who were evaluated for liver transplantation. We could demonstrate that the levels of both molecules increased with the Child's class of liver cirrhosis, independently of aetiology. TM was significantly elevated in Child A, B and C patients compared with patients without cirrhosis; TF only in Child C patients. The plasma TM and TF concentrations correlated with prothrombin time, activated partial thromboplastin time, and inversely with factor VII activity, cholinesterase serum activity, and serum albumin concentration. TM was elevated in patients with a bleeding tendency, but TM and TF did not differ between patients with or without prior thrombotic events. Further studies are warranted to clarify the underlying mechanisms that raise TM and TF plasma levels in liver disease with possible clinical consequences.

Adolescent↗
PubMed2001

Prevalence of a 23bp insertion in exon 3 of the endothelial cell protein C receptor gene in venous thrombophilia.

BACKGROUND: The endothelial cell protein C receptor (EPCR) enhances protein C activation by the thrombin-thrombomodulin complex. As evidence is accumulating that EPCR is an important component of the protein C anticoagulant pathway, polymorphisms in the EPCR gene might be candidate risk factors predisposing to venous thromboembolism (VTE). Recently, a 23bp insertion in exon 3 of the EPCR gene has been identified, which duplicates the preceding 23 bases and results in a STOP codon downstream from the insertion point. However, the clinical significance of this mutation in VTE remains to be clarified. METHODS AND RESULTS: In this study we evaluated the EPCR 23bp insertion in 889 patients with documented VTE and in 500 healthy controls. The prevalence of the EPCR insertion among patients was 0.1%, which was not significantly different compared to controls (0.6%, p = 0.1). CONCLUSIONS: Our findings showed that the EPCR 23bp insertion is very rare in both patients with VTE and the general population and failed to support an association between the EPCR 23bp insertion and an increased risk of VTE.

Adult↗
PubMed2000

Increased lipoprotein (a) levels as an independent risk factor for venous thromboembolism.

Elevation of serum lipoprotein (a) (Lp[a]) is a known risk factor predisposing to cardiovascular and cerebrovascular disease. However, little is known about the role of increased Lp(a) in venous thromboembolism (VTE). This study evaluated the role of Lp(a) among a panel of established hereditary thrombogenic defects in patients with VTE. A total of 685 consecutive patients with at least one episode of VTE and 266 sex- and age-matched healthy controls were screened with regard to activated protein C resistance, protein C, protein S, and antithrombin deficiency, elevated serum levels of Lp(a), and the factor V G1691A, MTHFR C677T, and prothrombin G20210A mutations. Elevated Lp(a) levels above 30 mg/dL were found in 20% of all patients, as compared to 7% among healthy controls (P <.001, odds ratio [OR] 3.2, 95% confidence interval [CI], 1.9-5.3). The coexistence of FV G1691A and elevated Lp(a) was significantly more prevalent among patients with VTE than in the control group (7% versus 0.8%; P <.001, OR 9.8, 95% CI, 2.4-40.7). No other established prothrombotic risk factor was found to be significantly combined with increased Lp(a). These data suggest that Lp(a) concentrations greater than 30 mg/dL are a frequent and independent risk factor for VTE. Furthermore, elevated Lp(a) levels might contribute to the penetrance of thromboembolic disease in subjects being affected by other prothrombotic defects, such as FV G1691A mutation.

Adolescent↗