Enoxaparin can be used safely in patients with severe thrombocytopenia due to intensive chemotherapy regimens.

Treatment with intensive chemotherapy regimens is frequently complicated by severe thrombocytopenia. During the period of severe thrombocytopenia, anticoagulant treatment is not uncommonly indicated for thromboembolic events or thromboprophylaxis in these patients. We report 10 hematological patients treated with intensive chemotherapy protocols that were anticoagulated with enoxaparin for catheter related central venous thrombosis and thromboprophylaxis.

Efficacy and safety of a prothrombin complex concentrate (Octaplex) for rapid reversal of oral anticoagulation.

Bleeding is the most serious adverse event of oral anticoagulants and is a major cause of morbidity and mortality in such patients. Rapid reversal of anticoagulation in bleeding patients or prior to urgent surgery is mandatory. The therapeutic options in these situations include administration of fresh frozen plasma (FFP), and recently of prothrombin complex concentrates (PCCs).

Risk factors for venous thromboembolism in hospitalized patients with acute medical illness: analysis of the MEDENOX Study.

Background: There is limited information about risk factors for venous thromboembolism (VTE) in acutely ill hospitalized general medical patients.

Methods: An international, randomized, double-masked, placebo-controlled trial (MEDENOX) has previously been conducted in 1102 acutely ill, immobilized general medical patients and has shown the efficacy of using a low-molecular-weight heparin, enoxaparin sodium, in preventing thrombosis. We performed logistic regression analysis to evaluate the independent nature of different types of acute medical illness (heart failure, respiratory failure, infection, rheumatic disorder, and inflammatory bowel disease) and predefined factors (chronic heart and respiratory failure, age, previous VTE, and cancer) as risk factors for VTE.

Warfarin therapy is feasible in CYP2C9*3 homozygous patients.

Background: Patients carrying variant CYP2C9 alleles are prone to bleeding complications under standard warfarin treatment. Our aim was to test the feasibility of warfarin therapy in patients with severe, inherited CYP2C9 deficiency. Methods: CYP2C9 genotypes and clinical characteristics were compared retrospectively in patients who maintain stable anticoagulation on low or regular doses of warfarin.

IGIV-C, a novel intravenous immunoglobulin: evaluation of safety, efficacy, mechanisms of action, and impact on quality of life.

The general safety and efficacy of intravenous immunoglobulin (IGIV) as treatment for idiopathic thrombocytopenic purpura (ITP) has been well-studied. The current study compares the safety and efficacy of a novel IGIV (IGIV-C; Gamunex, 10%) with a licensed solvent/detergent-treated product (IGIV-S/D; GamimuneN, 10%) in treatment of ITP. Ninety-seven pediatric and adult patients with acute and chronic ITP were treated in a multi-center, prospective, randomized, double-blind parallel group, non-inferiority trial at 26 international sites.

Prevention of venous thromboembolism in medical patients with enoxaparin: a subgroup analysis of the MEDENOX study.

The Medical Patients with Enoxaparin (MEDENOX) trial was a randomized, placebo-controlled study that defined the risk of venous thromboembolism (VTE) in acutely ill, immobilized, general medical patients and the efficacy of the low-molecular-weight heparin, enoxaparin, in preventing thrombosis. We performed a post-hoc analysis to evaluate the effect of 40 mg enoxaparin once daily on MEDENOX patient outcome in different types of acute medical illness (heart failure, respiratory failure, infection, rheumatic disorder and inflammatory bowel disease) and pre-defined risk factors (chronic heart and chronic respiratory failure, age, immobility, previous VTE and cancer). The primary outcome was the occurrence of documented VTE between days 1 and 14.

Heparin-induced thrombocytopenia with thrombotic sequelae: a review.

Heparin-induced thrombocytopenia (HIT) occurs in 1-5% of patients treated with heparin. The pathogenesis involves the formation of antibodies to heparin-platelet factor 4 complexes, and the major clinical sequelae are thrombotic. Diagnosis is based on a combination of clinical and laboratory data.

Inherited thrombophilia and gestational vascular complications.

Severe obstetric complications, including preeclampsia, intrauterine growth retardation, abruptio placentae, and stillbirth, constitute a major cause of maternal and perinatal morbidity and death. The etiology of these severe obstetric complications is still unknown. However, the frequent finding of structural and thrombotic changes in placental capillaries, which lead to inadequate fetomaternal circulation and decreased placental perfusion, and the high prevalence of heritable or acquired risk factors for thrombosis found in women with these complications strongly suggest a cause-and-effect relationship.

Long term follow-up after splenectomy performed for immune thrombocytopenic purpura (ITP).

Splenectomy is the only treatment of ITP known to have "curative" effects in a substantial fraction of patients. However, the true long-term outcome is uncertain and controversial because published series have not adjusted for the duration of follow-up. This IRB-approved retrospective study included all patients with ITP who underwent splenectomy between 1988-1993 at three major medical centers and required a minimum postoperative 5-year follow-up.

Complex regulation of acetylcholinesterase gene expression in human brain tumors.

To study the regulation of acetylcholinesterase (AChE) gene expression in human brain tumors, 3' splice variants of AChE mRNA and potentially relevant transcription factor mRNAs were labeled in primary astrocytomas and melanomas. AChE-S and AChE-R mRNA, as well as Runx1/AML1 mRNA accumulated in astrocytomas in correlation with tumor aggressiveness, but neither HNF3beta nor c-fos mRNA was observed in melanoma and astrocytomas. Immunohistochemistry demonstrated nuclear Runx1/AML1 and cellular AChE-S and AChE-R in melanomas, however, only AChE-S, and not the secreted AChE-R variant, was retained in astrocyte tumor cells.

Pregnancy-induced hypertension is associated with elevation of aggregability of red blood cells.

In order to differentiate between the contributions of cellular and plasmatic factors to the elevated aggregation in pregnancy-induced hypertension (PIH), we determined RBC aggregation in autologous plasma and in plasma-free medium. The aggregation was determined as a function of shear stress, to evaluate the strength of the intercellular interaction. These procedures were applied to RBC from PIH women (n=20), normotensive pregnant (NTP) women (n=15), and non-pregnant (control) women (n=15).

The stress-associated acetylcholinesterase variant AChE-R is expressed in human CD34(+) hematopoietic progenitors and its C-terminal peptide ARP promotes their proliferation.

Objective: Hematopoietic stress responses involve increases in leukocyte and platelet counts, implying the existence of stress responsive factors that modulate hematopoiesis. Acetylcholinesterase (AChE) is expressed in mammalian neurons and hematopoietic cells. In brain, it responds to stress by mRNA overexpression and alternative splicing, yielding the rare stress-associated "readthrough" AChE-R variant protein.

Self-management of oral anticoagulants with a whole blood prothrombin-time monitor in elderly patients with atrial fibrillation.

The efficacy of oral anticoagulants (OAC) in reducing the incidence of stroke in elderly patients with atrial fibrillation (AF) has been well documented. The intensity of OAC therapy and deviations in the prothrombin time (PT) are the strongest risk factor for bleeding complications in elderly patients. The aim of this study was to evaluate a more rigorous regulation of OAC by the use of a portable whole blood PT-monitor (CoaguChek) in elderly patients with AF (age 65-80 years).

Ex vivo expansion of megakaryocyte progenitors from cryopreserved umbilical cord blood. A potential source of megakaryocytes for transplantation.

Objective: Umbilical cord blood (CB) provides an alternative source of hematopoietic progenitor cells for transplantation; however, prolonged thrombocytopenia remains a major obstacle due to the low numbers of megakaryocyte progenitor (Mk-prog) cells and their subsequent delayed engraftment. In this study, we improved techniques for enrichment, cryopreservation, and ex vivo expansion of Mk-prog cells from CB.

Materials And Methods: CB mononuclear cells (MNC) were isolated and Mk-prog enriched by sedimentation on gelatin followed by centrifugation with Ficoll-Hypaque and cryopreserved.

Viral mediated gene transfer to sprouting blood vessels during angiogenesis.

Several experimental systems have been applied to investigate the development of new blood vessels. Angiogenesis can be followed ex-vivo by culturing explants of rat aorta 'rings' in biomatrix gels. This angiogenesis system was modified for the study of viral vector mediated gene transfer, using adenovirus, vaccinia- and retroviral vectors.

Detection of a thrombolysis-related reduction in red blood cell adhesiveness/aggregation using a simple slide test.

Increased red cell aggregability might have unfavorable rheological effects in the microcirculation. It has been suggested that thrombolysis-related hypofibrinogenemia might be associated with a reduced erythrocyte adhesiveness/aggregation. We followed the reduction in erythrocyte adhesiveness/aggregation using a simple slide test and image analysis that measures the spaces that are formed between the aggregated erythrocytes.

The use of low-molecular-weight heparin for the management of venous thromboembolism in pregnancy.

Thromboembolic disease is a rare, but important, complication of pregnancy that remains a leading non-obstetric cause of maternal death. The prevention and management of venous thromboembolism (VTE) in pregnant women is a complex area of medicine: a balance must be found between protecting the health of the mother and minimizing the risk to the unborn fetus. Until now, unfractionated heparin has been regarded as the drug of choice for the prevention and treatment of VTE during pregnancy.

Third-trimester unexplained intrauterine fetal death is associated with inherited thrombophilia.

Objective: To determine the risk of thrombophilias in women with unexplained intrauterine fetal deaths (IUFD).

Methods: All women with IUFD at 27 weeks' gestation or greater were initially assessed during a period of 26 months. Subjects with multiple pregnancies, congenital anomalies, intrauterine infection, chorioamnionitis, immune hydrops, diabetes mellitus, previous thromboembolism, and severe hypertensive disease were excluded.

Activation, processing and trafficking of extracellular heparanase by primary human fibroblasts.

Heparanase is a heparan-sulfate-degrading endoglycosidase that has important roles in various biological processes, including angiogenesis, wound healing and metastatsis. Human heparanase is synthesized as a 65 kDa latent precursor, which is proteolytically processed into a highly active 50 kDa form. Extracellular heparanase is found in various tissues and is utilized by both normal cells and metastatic cancer cells to degrade heparan sulfate moieties in basement membranes and extracellular matrices.

Duration of prophylaxis against venous thromboembolism with enoxaparin after surgery for cancer.

Background: Abdominal surgery for cancer carries a high risk of venous thromboembolism, but the optimal duration of postoperative thromboprophylaxis is unknown.

Methods: We conducted a double-blind, multicenter trial in which patients undergoing planned curative open surgery for abdominal or pelvic cancer received enoxaparin (40 mg subcutaneously) daily for 6 to 10 days and were then randomly assigned to receive either enoxaparin or placebo for another 21 days. Bilateral venography was performed between days 25 and 31, or sooner if symptoms of venous thromboembolism occurred.

[Signal transduction inhibitor--STI571--a new treatment for chronic myeloid leukemia (CML), which opens a new targeted approach to cancer therapy].

Chronic myeloid leukemia (CML), in most of the cases, is the molecular consequence of the t(9,22) translocation, resulting in the Philadelphia (Ph) chromosome and the creation of the fusion gene BCR-ABL. The fusion gene is translated to the protooncogen BCR-ABL, a constitutively activated tyrosine kinase that is linked to the malignant transformation. Thus, this tyrosine kinase became an attractive target for drug design.

Heparanase expression in human leukemias is restricted to acute myeloid leukemias.

Objective: Matrix metalloproteinases and an endo-beta-D-glucuronidase (heparanase) are enzymes that degrade the protein and carbohydrate constituents of basement membranes, thereby facilitating transendothelial migration of blood-borne cells. Heparanase activity was found to correlate with the metastatic potential of solid tumors. We evaluated heparanase expression, at the levels of gene and protein expression and activity in a variety of leukemias, and compared it with normal hematopoietic cells.

Anti-platelet factor 4/heparin antibodies from patients with heparin-induced thrombocytopenia provoke direct activation of microvascular endothelial cells.

Heparin-induced thrombocytopenia (HIT) is a serious complication that occurs in approximately 1-5% of patients treated with heparin and may be associated with severe thrombotic events. HIT is mediated by antibodies directed mostly to epitope(s) formed by complexes between heparin or other anionic mucopolysaccharides and platelet factor 4 (PF4). Anti-PF4/heparin IgG antibodies from six patients with HIT were affinity purified and assessed for interaction with human microvascular and macrovascular endothelial cells (EC).

Runx1/AML1 in leukemia: disrupted association with diverse protein partners.

Runx1/AML1, a chromosome 21q22 hematopoietic regulator, is frequently translocated in leukemia. Its protein product, a relatively weak transcriptional activator, becomes an effective transcriptional enhancer or repressor, when co-operating with transcriptional co-activators or co-repressors. Runx1/AML1 association with its partners is disrupted in leukemia.

The hypercoagulable state in thalassemia.

Thalassemia is a congenital hemolytic disorder caused by a partial or complete deficiency of alpha- or beta-globin chain synthesis. Homozygous carriers of beta-globin gene defects suffer from severe anemia and other serious complications from early childhood. The disease is treated by chronic blood transfusion.