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. During the period of severe thrombocytopenia the dosages of enoxaparin were reduced and no major bleeding occurred. Based on our experience we suggest that reduced dosages of low molecular weight heparins may be used relatively safely during transient severe thrombocytopenia.

Efforts to improve myocardial preservation during aortocoronary bypass procedures have led to the perfusion of saphenous vein segments with potassium cardioplegic (KCP) solutions after completion of the distal anastomosis. Recent reports show that the procurement of veins leads to varying degrees of damage, particularly to the endothelial surface, as a result of the dissection itself, the hydrostatic pressure required to distend the veins in obtaining hemostasis and the composition of the solutions used to irrigate the harvested segments. The biologic activity of arterialized vein segments is largely unknown. We tested the hypothesis that the degree of venous injury inherent in vein harvesting may be compounded by perfusion with a potassium-rich solution, a known vascular irritant. The external jugular vein was removed from 18 dogs. Half of the vein was perfused with 300 ml of a KCP solution at 4°C (40 mEq/l KCI, 10 ml sodium bicarbonate, pH 7.6, osmolarity 340 niosmol) and the other half with lactated Ringer's solution (LR). The treated vein was reversed and interposed into the excluded internal carotid circulation. A sham dissection was done on the opposite jugular vein. The veins were harvested after 6 weeks and assayed for spontaneous and arachidonate-stimulated (AS) prostacyclin activity as well as light microscopic analysis of morphologic changes. Spontaneous and AS production of prostacyclin did not differ significantly in the sham, LR and KCP groups: 1539' ± 709 and 4166 1802, 1569 ± 763 and 3767 ± 2706, 1860 ± 1233 and 3947 ± 3347 pg/mI). Light microscopic analysis revealed an intense adventitial fibrotic reaction in the KCP group and the appearance of fibroblast-like cells in the outer layer of the vein wall. The intima was intact in all three groups. We conclude that intimal damage sustained during harvesting is repaired within 6 weeks, and there is no impairment to surface production of prostacyclin. The intense adventitial fibrotic reaction observed in the KCPtreated group has not been previously reported, and its significance remains unexplained.

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). However, viral safety and thrombogenicity of PCCs remain issues of concern. In the present study, we administered Octaplex, a new solvent/detergent (S/D) treated and nanofiltered PCC, to excessively anticoagulated bleeding patients or to anticoagulated patients facing urgent surgery. Ten excessively anticoagulated patients with major bleeding and 10 anticoagulated patients awaiting surgery (median age 72.5 (43-83) years, 9 females) received a median dose of 26.1 IU/kg body weight (BW) of Octaplex for reversal of anticoagulation. Response to Octaplex was rapid with decline of INR within 10 min after Octaplex administration (from 6.1+/-2. to 1.5+/-0.3). Clinical response was graded as good in most patients (85%) and as moderate in the rest. Octaplex administration was uneventful in all patients. Following Octaplex administration, a small increase in F1+2 levels was observed in bleeding patients, whereas D-dimer level did not change significantly. We conclude that Octaplex is effective and safe in situations where rapid reversal of anticoagulation is needed.

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.RESULTS:The primary univariate analysis showed that the presence of an acute infectious disease, age older than 75 years, cancer, and a history of VTE were statistically significantly associated with an increased VTE risk. Multiple logistic regression analysis indicated that these factors were independently associated with VTE.CONCLUSIONS:Several independent risk factors for VTE were identified. These findings allow recognition of individuals at increased risk of VTE and will contribute to the formulation of an evidence-based risk assessment model for thromboprophylaxis in hospitalized general medical patients.

Summary 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; Gamimune®N, 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. Baseline data (age, duration of ITP, platelet counts, previous treatment) were comparable between groups. Patients were treated with 1 g/kg/day of IGIV-C or IGIV-S/D for 2 days. The primary endpoint, proportion of patients whose platelet counts increased from ≤20 × 109/L to ≥50 × 109/L within 7 days after dosing, was achieved by 35/39 (90%) and 35/42 (83%) of patients treated with IGIV-C and IGIV-S/D, respectively. A secondary endpoint, maintaining platelet counts ≥50 × 109/L for ≥7 days, was achieved by 29/39 (74%) of IGIV-C and 25/42 (60%) IGIV-S/D treated patients. Compared with IGIV-S/D, fewer patients treated with IGIV-C received corticosteroids beyond day 7 (p = 0.02). Efficacy was independent of the presence of isoantibodies or blood type, supporting mechanisms of effect different from anti-D treatments. Adverse events were generally mild and occurred with similar frequency in each group. Viral safety monitoring for HIV, HCV, HBV and Parvovirus B19 showed no seroconversions on study. In conclusion, IGIV-C is as safe and efficacious as IGIV-S/D in treatment of ITP.

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. This review describes the recent findings on the association between these obstetric complications and the various thrombophilias, and recent therapeutic approaches. Aspirin, which was regarded as the drug of choice for the prevention of such obstetric complications, has proved to be ineffective in a large clinical trial. The encouraging observations on the efficacy of low-molecular-weight heparins, which are also included in the recently published guidelines of The American College of Chest Physicians, are summarized in this review. However, controlled clinical trials are still necessary to allow the development of better clinical standards.

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. Complete response (CR) was defined as all postsplenectomy platelet counts >150 × 10 9 /L without treatment; partial response (PR) as platelet counts ≥50 × 10 9 /L without treatment; and failure as platelet counts <50 × 10 9 /L or receiving therapy after splenectomy. Seventy‐five patients identified with ITP underwent splenectomy from 1988 to 1993. Three patients died prior to 5‐year follow‐up, and 56 of the 72 patients (78%) were evaluable with follow‐up for five years or longer, median 7.5 years. The immediate postoperative complete remission rate was 77%; 57% of patients have remained in prolonged CR. Thirty‐seven patients (66%) have not required any therapy after splenectomy. Eight patients had platelet counts >150 × 10 9 /L for 4–8.5 years before relapsing; no clear plateau was attained in the remission curve. There was no operative mortality. Ten patients (18%) reported minor postoperative bleeding episodes. No life‐threatening infections, significant heart disease, or pulmonary hypertension developed after splenectomy in the 434 patient‐years of follow‐up. This study helps to define the long‐term results of splenectomy for ITP. Am. J. Hematol. 72:94–98, 2003. © 2003 Wiley‐Liss, Inc.

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. The development of the novel investigational drug STI 571 is based on its potent and selective ability to inhibit this fusion tyrosine kinase. In preclinical studies, STI 571 selectively inhibited the growth of CML cells that carry the Ph chromosome. In this review we discuss the drug development and design, its mechanism of action, the preclinical studies and the results of phase I and II clinical trials.

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.Materials and Methods. Heparanase expression was evaluated in leukocytes isolated from peripheral blood of 71 patients with myeloid and lymphoid leukemias, or non-Hodgkin's lymphoma. Analysis was performed at two levels: heparanase RNA was determined by reverse transcriptase polymerase chain reaction, and heparanase protein was evaluated by immunocytochemistry and flow cytometry.Results. In eight peripheral blood samples from normal donors, heparanase RNA was detected, and protein was found within the cytoplasm of granulocytes. In mononuclear cells derived from various leukemias, heparanase RNA was expressed in 14 of 15 acute myeloid leukemia (AML) samples. In contrast, cells derived from all 33 chronic lymphoblastic leukemia, all 7 non-Hodgkin's lymphoma, 7 of 8 chronic myeloid leukemia, and 6 of 8 acute lymphoblastic leukemia patients showed no detectable expression of the heparanase RNA. Heparanase protein was detected primarily within the cytoplasm of AML cells, indicating that the enzyme is produced and stored within the cytoplasm of myeloid cells, with limited expression on the cell surface.Conclusion. We propose that heparanase expression is associated with the myeloid lineage and may serve as an independent marker to support the identification of AMLs. (C) 2002 International Society for Experimental Hematology. Published by Elsevier Science Inc.

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. This led us to explore the hematopoietic involvement of AChE-R and its cleavable C-terminal peptide ARP. MATERIALS AND METHODS:AChE mRNA variants were labeled in CD34(+) hematopoietic progenitor cells by in situ hybridization. ARP expression was detected by multicolor flow cytometry. Bromo-deoxyuracil incorporation and viable cell counts served to evaluate the proliferative effects of ARP and suppressive effects of the AChE antisense oligonucleotide AS1 on CD34(+) cells. RESULTS:The distal enhancer, proximal promoter, and first intron of the human AChE gene include consensus binding sites for hematopoietically active and stress-induced transcription factors. CD34(+) cells from human cord blood were found to express all three variant AChE mRNAs, having different intracellular distributions. ARP was found in 5 to 15% of adult peripheral blood, bone marrow, and fetal CD34(+) cells (both committed CD38(+) and uncommitted CD38(-)) and in acute myeloid leukemia blasts. Externally supplied ARP by itself facilitated the proliferation of CD34(+) cells in an antisense suppressible manner. When combined with early-acting cytokines, ARP enhanced survival and expansion of CD34(+) cells up to 28 days in culture. CONCLUSIONS:Our findings support ARP, the C-terminal peptide of AChE-R, as a new hematopoietic growth factor that may promote the myelopoietic expansion and thrombopoiesis characteristic of stress and may be used to enhance the efficiency of ex vivo expansion for bone marrow transplantation.

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. The primary end point with respect to efficacy was the incidence of venous thromboembolism between days 25 and 31. The primary safety end point was bleeding during the three-week period after randomization. The patients were followed for three months.Results: The intention-to-treat analysis of efficacy included 332 patients. The rates of venous thromboembolism at the end of the double-blind phase were 12.0 percent in the placebo group and 4.8 percent in the enoxaparin group (P=0.02). This difference persisted at three months (13.8 percent vs. 5.5 percent, P=0.01). Three patients in the enoxaparin group and six in the placebo group died within three months after surgery. There were no significant differences in the rates of bleeding or other complications during the double-blind or follow-up periods.Conclusions: Enoxaparin prophylaxis for four weeks after surgery for abdominal or pelvic cancer is safe and significantly reduces the incidence of venographically demonstrated thrombosis, as compared with enoxaparin prophylaxis for one week. (N Engl J Med 2002;346:975-80.) Copyright (C) 2002 Massachusetts Medical Society.

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. The capacity of MNC to produce Mk-prog cells, assessment of CD34(+) and Mk-prog expansion in liquid culture, and analysis of the cell populations by flow cytometry were studied in cryopreserved separated CB and compared to whole CB and freshly separated samples.RESULTS:Excellent viability of greater than 85% was maintained after cryopreservation of separated CB. The number of colony-forming Mk-prog, myeloid, and erythroid progenitor cells did not decrease with cryopreservation. Flow cytometric analysis of cryopreserved cells revealed significant removal of the residual red blood cells while maintaining complete recovery of CD34(+), CD41(+) (Mk), myeloid, and T and B cells compared to noncryopreserved CB cells. There was no difference in the ability of separated cryopreserved MNC CB cells to be expanded in short-term liquid cultures.CONCLUSIONS:The conditions defined here for cryopreservation of gelatin/Ficoll-Hypaque separated CB, followed by ex vivo expansion of MNC, allowed complete recovery of proliferating CD41(+), CD34(+), Mk-prog cells, and other hematopoietic progenitors. Mk-prog cell expansion just before the scheduled transplantation is easily applicable by this technically simple and economical procedure that requires only an aliquot of red cell cell-depleted MNC to be separated from the CB unit before cryopreservation.

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. This study characterizes the processing and trafficking events associated with cellular activation of extracellular heparanase. We show that primary human fibroblasts are capable of binding and converting the 65 kDa heparanase precursor into its highly active 50 kDa form, concomitantly with its cytoplasmic accumulation. Heparanase uptake depends on the actin cytoskeleton integrity, resulting in a prolonged storage of the enzyme, mainly in endosomal structures. Heparanase endocytosis and its proteolytic activation are independent processes, indicating that heparanase cleavage is a cell surface event. Heparin completely inhibits heparanase endocytosis but only partially inhibits its association with the cells, suggesting that cell surface heparan sulfate moieties play a specific role in its endocytosis. Cellular binding and uptake of extracellular heparanase control its activation, clearance rate and storage within the cells.

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. However, because of its significant side effects (osteoporosis and heparin-induced thrombocytopenia), the inconvenient mode of administration and need for monitoring, unfractionated heparin is now being replaced by low-molecular-weight heparin (LMWH). There is a convincing body of clinical evidence from well-designed studies and prospective case series that supports the efficacy and safety of LMWH in pregnant women. There are also encouraging observations on the efficacy of LMWH in the prevention of severe obstetric complications, which are frequently associated with inherited or acquired thrombophilias. The recently-published guidelines of The American College of Chest Physicians (ACCP), summarized in this review, allows the development of higher clinical standards. However, there is concern over the greater cost of LMWH compared with unfractionated heparin and oral anticoagulants, and cost-effectiveness studies are needed.

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. Runx1/AML1 revealed weak linkage with ACHE promoter sequences, yet enhanced ACHE gene expression in co-transfected COS1 cells. The p300 co-activator and the ACHE promoter's distal enhancer facilitated this effect, which was independent of much of the Runx1/AML1 trans-activation domain. Surprisingly, GASP, a fusion product of green fluorescence protein (GFP) and ASP(67), a peptide composed of the 67 C-terminal amino acid residues of AChE-S, localized to COS1 cell nuclei. However, GARP, the corresponding fusion product of GFP with a peptide having the 51 C-terminal residues of AChE-E or GFP alone, remained cytoplasmic. Runx1/AML1 exhibited improved nuclear retention in GASP-expressing COS1 cells, suggesting modulated nuclear localization processes. Together, these findings reveal brain tumor-specific regulation of both expression and cellular retention of variant ACHE gene products.

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 average aggregate size (AAS) in plasma for PIH, NTP and control RBC was 38.7 +/- 3.2, 28.4 +/- 3.0, and 11.5 +/- 2.2 (P<0.05, between the three groups), respectively. For the same groups, the aggregation in plasma-free standard medium was 17.3 +/- 2.0, 12.0 +/- 1.2 and 10.0 +/- 1.6 (P < 0.05 between PIH and the other two groups), respectively. The contribution of plasma to the elevated aggregation was 75% and 88% for PIH and NTP respectively. tau(S50), the shear stress required to singly disperse 50% of the RBC population, in plasma and in standard medium, was about the same for PIH and NTP, and both were markedly higher than that for control RBC. These findings suggest that the increased aggregation of RBC from women with PIH, over those at of NTP women, may be due largely to changes in cellular factors and the increased aggregability has the potential to affect blood flow mainly in low-flow states such as in the placental intervillous space.

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. Treatment consists of stopping heparin, but, insofar as the risk of thrombosis remains high, treatment by alternative antithrombotic agents is indicated. Most clinical experience has been with danaparoid sodium and hirudin. The use of low-molecular-weight heparins (LMWH) in subsequent HIT episodes has been described, but is not recommended, especially with the introduction of new agents, such as oral thrombin inhibitors and pentasaccharides, which are hoped to reduce the use of heparins and the occurrence of HIT.