Motivational factors for blood donation in first-time donors and repeat donors: a cross-sectional study in West Pomerania.

Objectives: This study aimed to analyse motivational factors for blood donation in different donor groups.

Background: As the demographic change will result in a decrease of the population in age groups of blood donors, the risk of blood product shortage increases.

Methods: During a 12-month period, every sixth blood donor presenting at the blood donation centre of the University Hospital was asked to complete a self-administered questionnaire assessing motivational factors for blood donation.

PDK1 Determines Collagen-Dependent Platelet Ca2+ Signaling and Is Critical to Development of Ischemic Stroke In Vivo.

Objective: Activation of platelets by subendothelial collagen results in an increase of cytosolic Ca(2+) concentration ([Ca(2+)]i) and is followed by platelet activation and thrombus formation that may lead to vascular occlusion. The present study determined the role of phosphoinositide-dependent protein kinase 1 (PDK1) in collagen-dependent platelet Ca(2+) signaling and ischemic stroke in vivo.

Approach And Results: Platelet activation with collagen receptor glycoprotein VI agonists collagen-related peptide or convulxin resulted in a significant increase in PDK1 activity independent of second-wave signaling.

Thrombin generation, ProC(®)Global, prothrombin time and activated partial thromboplastin time in thawed plasma stored for seven days and after methylene blue/light pathogen inactivation.

Background: Methylene blue pathogen inactivation and storage of thawed plasma both lead to changes in the activity of several clotting factors. We investigated how this translates into a global loss of thrombin generation potential and alterations in the protein C pathway.

Materials And Methods: Fifty apheresis plasma samples were thawed and each divided into three subunits.

The impact of noninvasive, capillary, and venous hemoglobin screening on donor deferrals and the hemoglobin content of red blood cells concentrates: a prospective study.

Background: Hemoglobin (Hb) is screened before whole blood donation to protect donors from anemia. Recently, noninvasive methods have become available for Hb screening in blood donors. We compared a noninvasive, a capillary, and a venous method for Hb screening of blood donors.

Prevalence and clinical implications of anti-PF4/heparin antibodies in intensive care patients: a prospective observational study.

Data on the frequency of anti-platelet factor 4/heparin (PF4/H) antibodies and their association with outcomes in intensive care unit (ICU) patients are sparse. In this prospective, observational study we screened 320 consecutive surgical/medical ICU patients for anti-PF4/H antibodies by enzyme-immunoassay (EIA) for immunoglobulin (Ig)G/A/M separately and heparin-induced platelet activation assay (HIPA) at ICU admission (=baseline), day 6, and day 10. HIPA-positive patients were additionally tested by serotonin-release assay (SRA).

Anti-platelet factor 4/heparin antibodies in patients with impaired graft function after liver transplantation.

Background: Heparin, the standard perioperative anticoagulant for the prevention of graft vessel thrombosis in patients undergoing liver transplantation (LT), binds to the chemokine platelet factor 4 (PF4). Antibodies that are formed against the resulting PF4/heparin complexes can induce heparin-induced thrombocytopenia. LT is a clinical situation that allows the study of T-cell dependency of immune responses because T-cell function is largely suppressed pharmacologically in these patients to prevent graft rejection.

Alternative diagnosis to heparin-induced thrombocytopenia in two critically ill patients despite a positive PF4/heparin-antibody test.

Thrombocytopenia can cause diagnostic challenges in patients who have received heparin. Heparin-induced thrombocytopenia (HIT) is often considered in the differential diagnosis, and a positive screening can be mistaken as confirmation of the disorder. We present two patients who both received low-molecular-weight heparin for several days.

Evaluation of automated immunoassays in the diagnosis of heparin induced thrombocytopenia.

Background: Heparin-induced thrombocytopenia (HIT) is caused by platelet-activating antibodies that recognize platelet factor 4/heparin (PF4/hep) complexes. The in vitro demonstration of PF4/hep antibodies using functional and immunological methods is essential for optimal management of patients suspected to have HIT. Since functional assays are technically challenging and limited to specialized laboratories, antigen-binding assays are commonly used in routine laboratories.

Tissue factor exposing microparticles in inflammatory bowel disease.

Background: Circulating procoagulant microparticles (MPs) are thought to be involved in the pathogenesis of venous thromboembolism in patients with inflammatory bowel disease (IBD). However, the exposure of tissue factor, the primary initiator of coagulation activation, on microparticles (TF(+)MPs) and its association with hemostasis activation has not yet been studied in IBD patients.

Methods: In this case-control study 49 IBD patients (28 Crohn's disease, 21 ulcerative colitis) and 49 sex- and age-matched, healthy controls were included.

Storage of thawed plasma for a liquid plasma bank: impact of temperature and methylene blue pathogen inactivation.

Background: Rapid transfusion of fresh-frozen plasma (FFP) is desired for treating coagulopathies, but thawing and issuing of FFP takes more than 40 minutes. Liquid storage of plasma is a potential solution but uncertainties exist regarding clotting factor stability. We assessed different storage conditions of thawed FFP and plasma treated by methylene blue plus light (MB/light) for pathogen inactivation.

ProCGlobal and endogenous thrombin potential during pregnancy.

Objective: Pregnancy is a hypercoagulable state. We evaluated global markers of coagulation activation, ProCGlobal (Siemens Healthcare Diagnostics, Eschborn, Germany) and endogenous thrombin potential (ETP), in pregnant women with and without low-molecular-weight (LMW) heparin prophylaxis.

Study Design: We prospectively followed 113 healthy women and 61 women receiving LMW heparin prophylaxis throughout pregnancy.

Low dose acetylsalicylic acid and shedding of microparticles in vivo in humans.

Background: Microparticles (MPs) have procoagulant properties as shown in vitro and in animal models. Their role in haemostatic system activation at the site of a vascular injury in vivo in humans has not been studied.

Material And Methods: In a prospective randomized crossover study, 13 healthy volunteers were given 100 mg acetylsalicylic acid or placebo daily for 7 days.

Prediction of recurrent venous thromboembolism by endogenous thrombin potential and D-dimer.

Background: Increased thrombin generation is associated with an increased risk of recurrent venous thromboembolism. We investigated the relation between endogenous thrombin potential (ETP) and risk of recurrent venous thromboembolism and evaluated whether prediction of recurrence can be improved by a combined analysis of ETP and D-dimer.

Methods: We followed 861 patients with first spontaneous venous thromboembolism and determined ETP and D-dimer after discontinuation of anticoagulation.

Overweight, obesity, and the risk of recurrent venous thromboembolism.

Background: Excess body weight is a risk factor for a first venous thromboembolism. The impact of excess body weight on risk of recurrent venous thrombosis is uncertain.

Methods: We studied 1107 patients for an average of 46 months after a first unprovoked venous thromboembolism and withdrawal of anticoagulant therapy.

Prognostic value of T-cell receptor gamma rearrangement in peripheral blood or bone marrow of patients with peripheral T-cell lymphomas.

Peripheral T-cell lymphomas (PTCL) have a variable outcome. We have investigated the prognostic value of molecular staging in non-anaplastic PTCL. T-cell receptor gamma rearrangements were routinely determined in peripheral blood (n = 40) and bone marrow (n = 38) of patients with PTCL (75% unspecified) by conventional PCR at diagnosis.

Prediction of recurrent venous thromboembolism by measuring ProC Global.

In patients with venous thromboembolism (VTE) a laboratory assay that globally measures the overall thrombophilic tendency is not available. We hypothesized that determination of ProC((R)) Global, a plasma assay which tests the global function of the protein C pathway, could be used to stratify patients according to their risk of recurrent VTE. We prospectively followed 774 patients with first spontaneousVTE for a mean time of 52 months.

Low vitamin B6 levels and the risk of recurrent venous thromboembolism.

Low plasma vitamin B6, measured as pyridoxal-5'-phosphate (PLP), is associated with an increased risk of first venous thromboembolism (VTE). In a prospective cohort of 757 patients with first VTE we investigated the association of PLP levels with risk of recurrent VTE. After 4 years, the likelihood of VTE recurrence among patients with PLP < or =23.

Circulating P-selectin and the risk of recurrent venous thromboembolism.

The clinical relevance of high P-selectin levels in venous thrombosis is unknown. We prospectively followed 544 patients with first unprovoked venous thromboembolism (VTE) after cessation of anticoagulation and evaluated P-selectin as a risk factor of recurrent VTE. VTE recurred in 63 (12%) patients.

High-density lipoprotein and the risk of recurrent venous thromboembolism.

Background: High-density lipoprotein (HDL) protects against arterial atherothrombosis, but it is unknown whether it protects against recurrent venous thromboembolism.

Methods And Results: We studied 772 patients after a first spontaneous venous thromboembolism (average follow-up 48 months) and recorded the end point of symptomatic recurrent venous thromboembolism, which developed in 100 of the 772 patients. The relationship between plasma lipoprotein parameters and recurrence was evaluated.

Tissue factor-positive microparticles: cellular origin and association with coagulation activation in patients with colorectal cancer.

The pathogenesis of hypercoagulability in cancer is not entirely understood. We hypothesized that in cancer patients circulating tissue factor-positive microparticles (TF (+) MPs) are increased and associated with hemostatic system activation. In 20 patients with advanced colorectal cancer and in 20 age- and sex-matched controls, number and cellular origin of TF (+) MPs were determined in plasma by flow cytometry.

Homozygosity in the single nucleotide polymorphism Ser128Arg in the E-selectin gene associated with recurrent venous thromboembolism.

Background: The single nucleotide polymorphism (SNP) Ser128Arg in the E-selectin gene is overrepresented in certain patient populations with atherosclerosis or restenosis. As this SNP enhances tissue factor-triggered coagulation in humans during systemic inflammation, we hypothesized that it may also predispose for the development of recurrent venous thromboembolism (VTE).

Methods: A total of 585 patients were prospectively observed after first VTE for recurrent, objectively documented, symptomatic VTE.

The cardiovascular risk marker asymmetrical dimethylarginine is not affected by venous thromboembolism.

Asymmetrical dimethylarginine (ADMA) is an endogenous inhibitor of endothelial nitric oxide synthase, causes vasoconstriction, impairs cardiac function, and may predict cardiovascular risk. The prognostic value of plasma ADMA concentrations in acute vascular situations may be confounded by concomitant factors such as clot formation. In an effort to address the effect of hemostatic system activation, the authors have measured plasma concentrations of ADMA, its stereoisomer symmetrical dimethylarginine (SDMA), and L-arginine in 74 patients with suspected deep vein thrombosis (DVT).

Identification of patients at low risk for recurrent venous thromboembolism by measuring thrombin generation.

Context: Screening of patients with venous thromboembolism (VTE) for thrombophilic risk factors is common clinical practice. Because of the large number of risk factors, assessing the risk of recurrence in an individual patient is complex. A method covering multicausal thrombophilia is therefore required.