10 Clinical Trials for Various Conditions
The high percentage of failure using available non-surgical options to treat menorrhagia in women with bleeding disorders shows a continuing need for innovative treatments. This has led to development of this protocol in order to make available tranexamic acid as a potentially effective menorrhagia therapy option in women with an underlying bleeding disorder. We anticipate that Tranexamic Acid may be a beneficial choice for controlling menorrhagia in bleeding disorder patients.
Congenital bleeding disorders characterized by abnormal platelet granules include Gray Platelet syndrome (GPS; defective alpha-granules), Hermansky-Pudlak syndrome (HPS; defective delta-granules), and combined alpha delta-storage pool deficiency (alpha delta-SPD). Other diseases associated with variable defects in platelet gamma-granules include Chediak-Higashi, Griscelli, Wiskott-Aldrich, and Thrombocytopenia Absent Radius syndromes. These disorders are models for the study of organelle formation in megakaryocytes and platelets. Characteristics of megakaryocytopoiesis in these disorders have not been investigated because megakaryocytes could not be cultured from patients in sufficient quantities for experimental purposes. Recent advances have made it possible to culture megakaryocytes using serum-free media supplemented with recombinant human thrombopoietin (TPO). Such cultured human megakaryocytes, amplified from bone marrow-derived CD34+ stem cells, synthesize and store organellar proteins and produce functional platelets. In this protocol, we plan to obtain bone marrow aspirates from 40 children and adults (ages 2 to 80 years) with GPS, HPS, and related disorders. Patients admitted to the NIH Clinical Center on specific disease-related protocols will be enrolled in this protocol during their routine 3-5 day visits. We will culture megakaryocytes from CD34+ stem cells isolated from bone marrow aspirates. Studies of cultured megakaryocytes will include evaluation of granule membrane and soluble proteins using fluorescent antibodies and immunoelectron microscopy and comparison of RNA and protein expression patterns between normal and patient cells. Precautions will be taken to prevent the primary risk of the bone marrow aspiration, i.e., prolonged bleeding at the aspiration site. Standard diagnostic studies on the bone marrow sample may reveal information that may directly benefit patients. However, the broader benefit of this study is the acquisition of a better understanding of the characteristics of functional platelet disorders and the process of intracellular vesicle formation.
This is an open-label, multicenter study to evaluate the safety, tolerability, and efficacy of HMPL-523 in adult subjects with ITP.
The purpose of this study is to test the safety and effectiveness of Humate-P® to prevent bleeding in patients with von Willebrand Disease who are undergoing surgery.
The purpose of the study is to determine whether oral contraceptives, desmopressin acetate, and/or tranexamic acid are effective in the treatment of women with menorrhagia who are diagnosed with a bleeding disorder.
This open-label study is to determine the safety and efficacy of momelotinib in participants with either polycythemia vera (PV) or essential thrombocythemia (ET) who have not yet received treatment with a Janus kinase (JAK) inhibitor.
The purpose of this study is to understand physician treatment decisions in selecting specific second line treatments in pediatric ITP and to determine the effectiveness of different second line ITP treatments. Eligible patients are those ages 1-18 years who are starting on a new second line treatment for ITP, defined as any treatment other than IVIG, steroids, anti-D globulin, or aminocaproic acid. Enrolled patients remain on the study for approximately one year.
Advances in antiretroviral therapy (ART) have resulted in increased survival of the HIV-infected population; however, this gain in longevity is associated with an increased risk of cardiovascular disease (CVD). Although ART and traditional risk factors contribute to CVD in this population, heightened markers of immune activation, inflammation, and coagulation independently predict morbidity and mortality, suggesting that dysregulation of these systems plays a significant role in the increased risk of CVD. The investigators believe that platelet activation is an important driver in HIV-associated immune activation, inflammation, and coagulation, leading to an increased CVD pathophysiology and risk. Platelets initiate thrombus formation and also play a key role in vascular inflammation by releasing pro-inflammatory mediators and cross-talking with other relevant cell types including leukocytes. Researchers have described platelet hyperreactivity in chronic HIV infection. Importantly, the investigators demonstrated that one week of anti-platelet therapy (aspirin) decreased platelet activation and immune activation, with an improved trend in inflammation and immune parameters. The overall hypothesis is that platelet activation is a major driver of immune activation, inflammation, and thrombosis in ART-treated HIV infected patients. The purpose of the proposed proof-of-concept study is to understand the mechanism(s) by which anti-platelet therapy improves immune and inflammatory parameters in chronic HIV infection. To test this, the immune modulating and anti-inflammatory effects of 24 weeks of the anti-platelet drug aspirin as compared to the anti-platelet drug clopidogrel will be evaluated. Given their different mechanisms of action and inhibitory potency, the investigators can differentiate whether the potential benefits are mediated via inhibition of arachidonic acid (aspirin) or inhibition of ADP (clopidogrel) or by the antithrombotic activity. A secondary goal is to perform multidimensional assays of platelet activity and thrombogenicity alongside immune activation assays and careful assessments of traditional risk factors and medication regimens, to understand which parameters are highly associated with thrombogenicity.
Sickle cell disease (SCD) is often referred to as a hypercoagulable state. However, the contribution of coagulation activation to the pathogenesis of SCD remains uncertain. Pulmonary hypertension (PHT) is a common complication associated with significant morbidity and mortality. Autopsy studies of SCD patients with PHT show evidence of in situ thrombosis involving pulmonary vessels, similar to findings in non-sickle cell patients with PHT. Anticoagulation has been reported to be of benefit in non-sickle cell patients with PHT. With the evidence of increased coagulation activation in SCD, PHT represents a clinical endpoint that may be used to evaluate the contribution of coagulation activation to the pathophysiology of SCD. The investigators hypothesize that increased thrombin generation, as well as platelet activation are central to the pathophysiology of SCD and contribute to the occurrence of several SCD-related complications, including PHT. As a consequence, treatment modalities that down-regulate thrombin generation would be expected to delay the progression of PHT and result in improved survival in patients with SCD.
Blood contains red blood cells, white blood cells, and platelets, as well as a fluid portion termed plasma. We primarily study blood platelets, but sometimes we also analyze the blood of patients with red blood cell disorders (such as sickle cell disease), white blood cell disorders, and disorders of the blood clotting factors found in plasma. Blood platelets are small cell fragments that help people stop bleeding after blood vessels are damaged. Some individuals have abnormalities in their blood platelets that result in them not functioning properly. One such disorder is Glanzmann thrombasthenia. Most such patients have a bleeding disorder characterized by nosebleeds, gum bleeding, easy bruising (black and blue marks), heavy menstrual periods in women, and excessive bleeding after surgery or trauma. Our laboratory performs advanced tests of platelet function and platelet biochemistry. If we find evidence that a genetic disorder may be responsible, we analyze the genetic material (DNA and RNA) from the volunteer, and when possible, close family members to identify the precise defect.