bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human Thrombin Production from Single Donor Plasma Using Thrombin Processing Device -TPD™ .
Authors: Kumar Vijay , Zhu Haihong , Chapman John R. 
Published: April 2020

Abstract
Introduction: Thrombin is routinely combined in surgical practice with a fibrinogen source to prepare fibrin sealant to promote hemostasis or with platelet concentrates to prepare gels to enhance wound healing. Currently, thrombin is derived primarily from bovine tissue. The purpose of this study was to evaluate the robustness and reproducibility of the TPD, a new handheld sterile disposable designed to generate active human thrombin in less than 30 minutes from autologous or single donor allogeneic plasma. Thrombin is generated in the device from plasma via the activation of the alternative pathway of the coagulation cascade and thrombin inhibitors (e.g., antithrombin III) are concurrently depleted by a modified Cohn fractionation process. By eliminating the risk of the potential for allergic reactions and blood borne pathogen transmission, autologous human thrombin can be considered the safest thrombin for the preparation of fibrin sealant and platelet gels.
Materials and Methods: Active thrombin was prepared by combining 4 ml of thrombin reagent (a mixture of calcium chloride, ethanol and water) and 11 ml of plasma in a reaction chamber containing negatively charged particles (TPD). The mixture was incubated for 25 minutes and then the active thrombin serum harvested. The thrombin was prepared at ambient room temperatures of 18°C or 25°C (n=100/group) to assess robustness.
Results: The thrombin activity (mean ± S.D.) produced at 18°C and 25°C ambient temperature was 101 ± 22 IU/ml (n=100) and 90 ± 26 IU/ml (n=100), respectively. The average volume of thrombin serum harvested from the TPD was 9.2 ml in both groups. The thrombin concentration generated was demonstrated to rapidly (&lt;5 seconds) coagulate fibrinogen concentrates at a 1:1 ratio (volume to volume). The thrombin maintained clotting activity for ≥4 hours storage at room temperature using a tilt clot test with cryoprecipitate as the source of fibrinogen (less than 5 second clot time).
Conclusions: The results demonstrate that the TPD is able to consistently generate high thrombin activity that is stable for ≥ 4 hours. There was no significant difference in thrombin production at the two extremes of the normal ambient temperature (18° C and 25° C) demonstrating the robustness of the device. The device offers a simple and rapid method for preparing active thrombin from autologous or single donor allogeneic human plasma so as to avoid the safety issues associated with bovine thrombin.
Acquired Hemophilia: Single Center Experience with a Standardized Approach.
Authors: Sucker Christoph , Zotz Rainer B. , Scharf Rudiger E. , Gerhardt Andrea 
Published: April 2020

Abstract
Background: Acquired hemophilia is a rare, often life-threatening, bleeding diathesis caused by autoantibodies, most commonly directed against factor VIII:C. Several clinical studies have reported mortality rates of 16–22 % for affected patients depending on age, inhibitor titre levels, and individual response to treatment. Patients in whom the inhibitor could not be eliminated had a mortality rate of 42 %, providing a strong argument for the necessity of rapid and long-term inhibitor elimination as part of the therapeutic concept. To date, no general consensus exists on the best therapeutic approach.
Patients and Methods: The history and clinical course of ten consecutive patients (4 females, 6 males, mean age [± SD] 61 ± 7 years) diagnosed for acquired hemophilia A in our department are reviewed with special regard to efficacy and side-effects of treatment. Initial treatment consisted of corticosteroids (1 mg/kg) in combination with either azathioprin (1.5 mg/kg, n=7) or cyclophosphamide (1.5 mg/kg, n=3). Severe bleeding complications were treated by recombinant factor VIIa (NovoSeven).
Results: On admission, mean inhibitor titres [± SD] were 83 ± 116 Bethesda units (BU) per milliliter with a range from 10–333 BU. Six of the 10 patients had concomitant disease (chronic obstructive lung disease [n=3], rheumatoid arthritis [n=2], sarcoidosis [n=1]). Immunosuppressive therapy had to be switched from azathioprin to cyclophosphamide in 4 of 7 patients during the clinical course because of treatment-associated hepatitis. Seven of the 10 patients achieved complete remission defined as return to normal factor VIII:C activity and undetectable factor VIII inhibitor titres. Remarkably, the period until complete remission in 2 patients with inhibitor titres above 200 BU was longer (mean 4 months vs. 6 to 8 weeks). Two patients are on immunosuppressive treatment since two months only and experienced a decrease in inhibitor titres, but no increase in factor VIII:C yet. Immunosuppressive therapy was complicated by infection (n=2), development of insulin-dependent diabetes mellitus (n=2), and vertebral fractures (n=1).
Conclusion: Our experience in this limited number of patients demonstrates that immunosuppressive treatment with corticosteroids and cytotoxic agents yields high response rates in acquired hemophiliacs. However, the high frequency of side-effects has to be carefully considered, particularly in elderly patients. In addition, elimination of inhibitors may be delayed specifically in patients with high inhibitor titres, increasing the cumulative risk of bleeding and treatment-associated toxicity.
Association of Acquired Von Willebrand Syndrome with Primary (AL) Amyloidosis.
Authors: Kos Cynthia A. , Ward Jennifer E. , Malek Karim , Sanchorawala Vaishali , Wright Daniel G. , O’Hara Carl , Connors Lawreen , Skinner Martha , Seldin David C. 
Published: April 2020

Abstract
Easy bruising is a common clinical symptom in primary (AL) amyloidosis, and can occur through multiple mechanisms. Infiltration of amyloid fibrils into thin-walled capillaries leads to mechanical fragility predisposing to petechiae and purpura, with periorbital “raccoon-eye” purpura being pathognomonic of AL amyloidosis. Another mechanism predisposing to bleeding in AL amyloidosis is adsorption of coagulation factors to amyloid fibrils. In 1977, Furie et al. reported (New England Journal of Medicine) that elevation of the clotting times is most commonly due to deficiency of factor X, and other investigators have since reported deficiencies of factors II, V, IX, or XIII. We have demonstrated that remission of the underlying plasma cell dyscrasia after high dose melphalan chemotherapy and autologous stem cell transplantation can lead to remission of the acquired factor X deficiency (Choufani et al., Blood 2001). From 2000–2004, four amyloidosis patients presented to Boston University Medical Center with bleeding and a prolonged activated partial thromboplastin time (aPTT), but with no such factor deficiency. Instead, they were found to have abnormal von Willebrand ristocetin cofactor (vWF:RCo) and/or factor VIII (FVIII:C) activities, with normal vWF antigen (vWF:Ag), consistent with a functional defect in von Willebrand factor (vWF). None of the patients had a prior history or family history consistent with congenital von Willebrand’s disease, thus they were diagnosed with acquired von Willebrand syndrome (AvWS). AvWS has most often been reported in association with other lymphoproliferative or myeloproliferative disorders. The aPTT was prolonged in three out of the four cases. Loss of high molecular weight multimers (HMWM) was observed in two of the four cases. Two of the patients were treated with high-dose intravenous melphalan followed by autologous stem cell transplantation and achieved remission of their underlying plasma cell disease; in addition, the bleeding diathesis ceased and the coagulation parameters normalized, indicating reversal of the AvWS with effective treatment of AL amyloidosis.
Improved Coagulation in Bleeding Disorders by NASP Treatment.
Authors: Johnson Kirk W. , Broze George J. , Liu Tongyao 
Published: April 2020

Abstract
Additional therapeutic options are needed for patients with bleeding disorders such as hemophilia A, hemophilia B, and severe von Willebrand disease. A novel treatment approach which may benefit such clotting disorders has been identified that, parodoxically, involves heparin-like sulfated polysaccharides. Select molecules of this broad class are largely devoid of anticoagulant activity and are here denoted Non-Anticoagulant Sulfated Polysaccharides (NASPs). Candidate NASPs were shown in clotting assays to demonstrate at least ten-fold lower anticoagulant activity as compared to heparin. Moreover, a subset of NASPs, including pentosan polysulfate (PPS) and fucoidan, improved (i.e. accelerated) the clotting time of human hemophilia A and hemophilia B plasmas or plasma with reduced FVII levels when tested at concentrations ranging from 4–500 nM in dilute prothrombin time (dPT) assays. A broad window of efficacy was evident with both PPS and fucoidan. A mechanism involving potent blockade of the extrinsic pathway downregulator, Tissue Factor Pathway Inhibitor (TFPI), was implicated from modified dPT clotting tests. Improved hemostasis in vivo was observed in mice with hemophilias A or B following low dose subcutaneous administration of PPS or fucoidan, or a combination of NASP plus factor supplement. Studies in hemophilic dogs are in progress. Accordingly, administration of select NASPs may represent a unique approach for treating multiple bleeding disorders.
Therapy of Hereditary TTP with ADAMTS13 Deficiency - A Case Report and Review of the Literature.
Authors: Huang Jian , Jin Jie , Meng Haitao , Zhou Yuhong , Yu Rongxi , Liu Fang , Ruan Changgen 
Published: April 2020

Abstract
Deficiency of von Willebrand factor (VWF) cleaving protease ADAMTS13 is associated with the development of thrombotic thrombocytopenic purpura (TTP). ADAMTS13 gene mutations cause the hereditary TTP. We describe a patient with relapsing TTP, who failed to achieve sustained remission despite therapies with plasma exchange, steroids, vincristine and ATG. There was lower ADAMTS13 inhibitor titre and lower activity of ADAMTS13 enzyma in the patient’s plasma. Sequence analysis of DNA amplified by polymerase chain reaction showed that the patient was homozygous for two novel missense mutations in TSP1 repeated motif domain of ADAMTS13. In both mutations cytisine were subtituded by thymine. One was a Serine to Leucine substitution in NT 3152, exon21(codon S903L); the other is a Arginine to a Tryptophan substitution in NT3727, exon 25(codon R1094W), while both parents were heterozygous for the same mutation. The patient was dialogue as hereditary TTP. The patient receives 600 to 800 ml plasma transfusion every 3 weeks and now she is very well and works again.
Hereditary TTP with ADAMTS13 deficiency could be treated with the infusion of only a few units of plasma, without plasma exchange. Gene therapy may eventually cure hereditary TTP.
Management of Refractory Hemorrhage in a Kala-Azar Patient with Thrombocytopenia and Coagulopathy by Using Recombinant Factor VIIa (rFVIIa).
Authors: Leblebisatan Goksel , Sasmaz Ilgen , Antmen Bulent , Kilinc Yurdanur , Celik Umit Sizmaz , Mert3 Kurthan , Aksaray Necmi 
Published: April 2020

Abstract
Objective: Platelet transfusion is used for the treatment of acute hemorrhages in diseases other than immunological events, which lead to severe thrombocytopenia. Besides the diseases in which production of platelets is completely terminated in the bone marrow and the platelet requirement is increased, immune thrombocytopenia and alloimmunization may also result in not being able to achieve the desired platelet levels with platelet transfusion, and life threatening hemorrhages. rFVIIa which is used for the management of life threatening hemorrhages in hemophiliac patients with inhibitors and in cases of acquired coagulopathies has also been used successfully in patients with thrombocytopenia. Here we present a case with a diagnosis of kala-azar, where nasal hemorrhage couldn’t be managed with conventional methods and required continuous replacement, and finally treated successfully by using rFVIIa.
Case: At admittance to hospital, hepatosplenomegaly and pancytopenia were detected in the fifteen year old male patient. He was diagnosed with kala-azar upon the detection of Leishmania donovani amastigote form in the examination for bone marrow aspiration. Treatment with sodium stibogluconate was initiated (60 mg/kg). Replacements were performed in the patient due to thrombocytopenia and anemia, who developed nasal hemorrhage during follow-up and had anterior nasal cushion placed. The patient was supplemented with fresh frozen plasma, vitamin K and fibrinogen for his acquired coagulopathy. Since coagulopathy wasn’t corrected and nasal hemorrhage continued actively, 5-minute infusions of rFVIIa were administered to the patient at a dose of 4.8 mg (120 microgram/dl) three times every two hours. His hemorrhage was stopped by rFVIIa treatment.
Conclusion: Our case demonstrated that use of rFVIIa for the management of hemorrhage in thrombocytopenic patients is also feasible in cases other than coagulopathy and that it may be an option for patients with hemorrhages that can not be managed with intensive platelet and plasma transfusions. This result shows that rFVIIa can be used effectively in other diseases other than hematological disorders that cause hemorrhage due to coagulopathy and thrombocytopenia.
Interferon-α-Associated Acquired Factor VIII Inhibitor.
Authors: Hayek Fadi N. , Wagner Stephanie , Laber Damian A. , Sharma Vivek R. 
Published: April 2020

Abstract
Introduction: Development of an acquired inhibitor to factor VIII (acquired hemophilia) is a rare autoimmune phenomenon that has been associated with a variety of medical conditions such as autoimmune diseases, malignancies, drugs like penicillin and postpartum state. It often presents with acute, life-threatening hemorrhage. Interferon alpha (IFN) is an immune system modulator that is widely used for the treatment of hepatitis C and various malignancies. It is known to stimulate or exacerbate autoimmune diseases and has been described in four separate reports to be associated with the development of inhibitors to factor VIII. All but one of these four cases represented patients with underlying malignancy or congenital hemophilia A.
Case Report: Our patient is a 55-year old non-hemophiliac with no prior diagnosis of cancer who developed new-onset bruising while on IFN therapy for hepatitis C. This was not evaluated or treated further at that time. Six months after completing IFN therapy, he presented to the emergency room with respiratory distress. On examination, he was found to have a large supraglottic hematoma and underwent an urgent tracheostomy for impending respiratory failure. This was followed by severe postoperative bleeding which the otolaryngologists were unable to control surgically. Laboratory testing showed a prolonged activated prothrombin time and infusion of fresh frozen plasma failed to achieve hemostasis. A hematology consultation was obtained and the patient was treated with activated recombinant factor VII (rVIIa) which resulted in prompt cessation of bleeding. Existence of factor VIII inhibitor was confirmed by abnormal mixing studies (no correction), low factor VIII activity (2.1%) and high inhibitor titer (42 Bethesda Units/ml [BU]). Following hospital discharge, inhibitor titers slowly declined to less than 1 BU after immunosuppressive therapy with steroids, alkylating agents and rituximab given sequentially over a period of nine months. The factor VIII activity has also increased to 15%. The patient has since had occasional mild to moderate soft tissue bleeding which responded well to rVIIa.
Conclusion: One previous report has described a patient without a history of hemophilia or cancer who developed factor VIII inhibitor while being treated with pegylated IFN for hepatitis C. Our patient represents only the second such report and adds to the slowly growing body of literature pointing to this association. Although this data is anecdotal, we believe that the potential for such inhibitors to produce serious and even life threatening hemorrhage warrants awareness of and attention to this possibility by clinicians treating patients with IFN. Simple clinical vigilance along these lines may help identify and address this condition in a timely fashion before it has a chance to produce catastrophic bleeding.
Technozym® ADAMTS-13 ANTIGEN ELISA - A New Assay for Specific Quantification of the vWF Cleaving Protease ADAMTS-13.
Authors: Vetr Helga , Geiter Sabine , Scheiflinger Fritz , Dockal Michael , Binder Bernd R. 
Published: April 2020

Abstract
Defects in activity and/or antigen levels of ADAMTS-13, the von Willebrand Factor (vWF) cleaving protease, are viewed as the main cause inducing the microvascular thrombotic disorder TTP (thrombotic thrombocytopenic purpura) that is in more than 90% of cases fatal if not treated early and appropriately. Malfunction of ADAMTS-13 with respect to cleave multimeric vWF can be caused by auto-antibodies directed against ADAMTS-13, by decreased presence of ADAMTS-13 in the circulation or by defective activity of ADAMTS-13. Therefore rapid and reliable diagnosis of ADAMTS-13 parameters is a clinical need. We present here an assay for quantification of ADAMTS-13 antigen levels. The assay is a regular double sandwich ELISA employing a monoclonal antibody for capturing ADAMTS-13 from the sample by binding to the CUB domains. The bound ADAMTS-13 is detected by a polyclonal antibody conjugate. The sensitivity of the assay is below 10% of the normal antigen level. In normal samples a wide range (50% to 200%) of the mean level was observed. In idiopathic TTP plasmas also a wide range of antigen levels was observed but with a slighltly lower mean value than in normal samples. Samples from hereditary TTP mostly showed lower antigen levels than normal samples. Thus we could show that this assay provides a useful tool for measuring ADAMTS-13 antigen levels. In combination with our activity assay, which is being developed in parallel, it will be possible to establish ratios of activity and antigen which could provide more insight into the mechanisms of ADAMTS-13 deficiencies than the individual values for antigen and activity.
The C-Terminal α-Helix of von Willebrand Factor Domain A2 Interacts with ADAMTS13 C-Terminal Domains To Regulate Substrate Cleavage.
Authors: Gao Weiqiang , Anderson Patricia J. , Majerus Elaine M. , Tuley Elodee A. , Sadler J. Evan 
Published: April 2020

Abstract
ADAMTS13 is a member of the A Disintergrin And Metalloprotease with ThromboSpondin type I repeat family, and it cleaves the Tyr1605-Met1606 bond in the von Willebrand factor (VWF) central A2 domain, thereby decreasing platelet adhesion mediated by VWF. Recently a minimal substrate for ADAMTS13 was characterized that consists of GST linked to Asp1596-Arg1668 with a C-terminal 6×His tag (VWF73). Further removal of 9 amino acids that comprise a predicted C-terminal α-helix (VWF64) appeared to eliminate cleavage by plasma ADAMTS13, suggesting a critical role for this helix in substrate recognition. We obtained similar results, but VWF64 was cleaved significantly at long reaction times. For example, plasma ADAMTS13 (0.3 nM, one-tenth of normal plasma) cleaved 50% of 65 nM VWF73 in 2 hours and 50% of 62 nM VWF64 in 24 hours. Similar results were obtained in either 50 mM HEPES, pH 7.4, 150 mM NaCl, 5 mM CaCl2, 0.1 μM ZnCl2, or 5 mM Tris-HCl, pH 8.0, 10 mM BaCl2. By amino acid sequencing, ADAMTS13 was shown to cleave the Tyr1605-Met1606 bond of VWF64. Truncation of ADAMTS13 after certain structural domains had different effects on substrate cleavage. Using 3 nM enzyme for 30 min, VWF73 was cleaved ~2-fold faster by ADAMTS13 truncated after the spacer domain (MDTCS) than by ADAMTS13 truncated after the cysteine-rich domain (MDTC). Conversely, VWF64 was cleaved ~3-fold faster by MDTC than by MDTCS. Also, in 30 min MDTCS cleaved 70% of VWF73 and &lt;10% of VWF64, whereas MDTC cleaved 40% of VWF73 and 30% of VWF64. ADAMTS13 truncated after the first TSP1 repeat (MDT) or the disintegrin domain (MD) had markedly reduced activity, but with prolonged incubation (24 h) at increased concentration (30 nM) both enzymes cleaved most of VWF64 and VWF73 at the expected site. No aberrant cleavage products were detected by Western blotting. The metalloproteinase domain alone (M) was inactive. The selective effects of deleting the cysteine-rich or spacer domain suggest that the C-terminal α-helix of the VWF A2 domain is not essential but facilitates substrate recognition by interacting with specific C-terminal domains of ADAMTS13, particularly the cysteine-rich and spacer domains.
A Case of Prekallikrein Deficiency in a Pediatric Patient.
Authors: Carpenter Shannon L. , Britton Howard A. 
Published: April 2020

Abstract
Prekallikrein (also known as Fletcher factor) is described as one of the contact factors, and when converted to its active form, kallikrein, is responsible for the activation of factor XII and initiation of the intrinsic pathway of the coagulation cascade. Kallikrein also converts high-molecular-weight kininogen to bradykinin, which acts as a potent vasodilator. Deficiency of prekallikrein was first described in 1965 as an autosomal recessive disorder. Hereditary deficiency of prekallikrein is not associated with a clinical bleeding disorder, but does result in a prolonged activated partial thromboplastin time (aPTT). Most cases of prekallikrein deficiency are identified through routine screening. We present a young man who was referred to our Hemophilia and Thrombophilia Treatment Center for a significantly prolonged aPTT and subsequently found to have prekallikrein deficiency. NP is a 7 year-old boy who was found to have an aPTT of 209.6 seconds on pre-operative evaluation for PE tubes and adenoidectomy. Prothrombin time (PT) was normal at 14.7 seconds, with an INR of 1.2. There was no personal or family history of bleeding. Past medical history did include bipolar disorder and attention deficit disorder, for which the patient was taking olanzapine and depakote. A 1:1 mixing study with normal plasma led to complete correction of the aPTT to 28.9 sesconds. Levels of factors VIII, IX, XI, and XII were normal at 98%, 92%, 99% and 129%, respectively. High molecular weight kininogen level was also normal. Thrombin time was normal at 17.1 sec. An incubated aPTT was performed over 3 hours with decrease in the aPTT from 179 seconds to 72 seconds, a phenomenon that has been reported previously, and is thought to be due to auto-activation of factor XII. Prekallikrein was measured at less that 15% (normal reference 55–207%). The patient subsequently underwent adeno-tonsillectomy without any excessive bleeding. This case serves as another example of the benign causes for a prolonged aPTT in the pre-operative setting in addition to those such as lupus anticoagulant or factor XII deficiency. Deficiency of prekallikrein should be included in the differential diagnosis of a prolonged aPTT, particularly in the absence of bleeding symptoms.