Two Consecutive Invasive Surgeries Utilizing Zymogen Protein C (ZPC) That Enhanced Patient Safety and Reduced Costs.

This case report describes a major surgical procedure for a protein C-deficient, hypercoagulable patient who underwent two back-to-back invasive surgeries, hip replacement, and spinal stenosis correction. The patient, an 84-year-old male with a history of deep vein thromboses (DVT) and pulmonary emboli (PE), was treated pre-, peri-, and postoperatively with zymogen protein C (ZPC-Baxter, International) and recovered without clotting or increased bleeding. During the procedure, the patient was not administered any other anticoagulants. There have now been several case reports on different patients with unrelated teams in various locations worldwide using zymogen protein C during surgical procedures. Thus, this procedure is becoming a viable choice for patients with a high probability of clotting during and after invasive surgery. This case focuses on accomplishing safer surgery and reducing costs, by using less ZPC while accomplishing two surgeries in one procedure. As a result, this procedure might be useful for many medical situations where acquired protein C deficiency could be a problem (e.g., sepsis, pregnancy, etc.). This approach may have greater application to medical conditions other than protein C deficiency, where clotting and inflammation can become issues.

A novel diagnostic algorithm for heparin-induced thrombocytopenia.

INTRODUCTION: While diagnostic algorithm using PF4-heparin enzyme-linked immunosorbent assay (ELISA) optical density (OD), and heparin neutralization assay (HNA), or 4T score have been proposed to replace serotonin-release assay (SRA) for heparin-induced thrombocytopenia (HIT), their performance against SRA is unclear. In this study, we proposed and validated the performance of a new algorithm combining PF4-heparin ELISA optical density (OD), HNA and 4T score against SRA for HIT diagnosis. METHODS: Heparin neutralization assays were performed on specimens submitted for HIT testing with positive PF4-heparin ELISA from December 2015 to September 2017, which were separated into a "training" and a "validation" data set. 4T scores were calculated for ELISA positive cases. RESULTS: A total of 123 consecutive unique patient samples had positive PF4-heparin ELISA with also HNA data, SRA data, and 4T scores available. Compared to SRA, a "laboratory criteria" (ELISA OD ≥ 1.4 and HNA ≥ 70%) had a sensitivity of 88% (14/16) and specificity of 91% (42/46), and a "combined criteria" (4T score = 8, or 4T score = 6 or 7 and ELISA OD ≥ 1.0, or 4T score = 4 or 5 and ELISA OD ≥ 2.0) had a sensitivity of 75% (12/16) and specificity of 98% (45/46) in the training data set. Laboratory and combined criteria had 90% (56/62) concordance rate. Importantly, for these concordant cases, the diagnostic specificity is 100% (46/46). Based on the data, a novel diagnostic algorithm combining these 2 criteria was proposed and validated prospectively. CONCLUSION: A novel algorithm has high diagnostic accuracy and potentially could eliminate the need for SRA testing in at least 90% patients with suspected HIT.

A Compelling Case for the Use of Perioperative Zymogen Protein C for Increased Patient Safety.

It is imperative to maintain normal blood flow to provide adequate oxygen supply to specific organs and cells, as well as for the removal of metabolic byproducts. Therefore, any situation that results in blood clotting can injure or kill living tissues. In this paper, we describe a case where a protein C deficient subject who would, by all medical indicators, be at 100 % risk of experiencing thrombophlebitis, deep vein thrombosis, and or lung emboli, is able to escape all pathologies by using perioperative zymogen protein C (ZPC). This protein C deficient patient has a long history of blood clotting, particularly from surgical procedures. The patient is 81 years old and first experienced clotting due to hernia surgery in 1964, when he was hospitalized for 16 days post-surgery with life threatening complications. It was later determined in 1980, after many episodes, that the patient had hereditary protein C deficiency at the 38 % level. In his hernia surgery, perioperative ZPC was used along with accepted anticoagulation procedures with no blood clots or other related side effects occurring. This procedure can greatly benefit protein C deficient patients, and could potentially find use for non-PC deficient patients in surgeries and a variety of other medical treatments. This particular case helps to validate the importance of ZPC in effecting safer surgery in high-risk patients. It also supports the mechanism of ZPC acting as an anticoagulant without causing bleeding. Most importantly, each clinical case study represents a unique combination of surgeon, hematologist, medical staff, and patient functioning as a coordinated team. In this case, smaller amounts of very expensive ZPC achieved safe and efficacious results, which is hugely important for future clinical applications when considering the production cost of ZPC. More studies must be done to establish minimum dosing while achieving safe and efficacious outcomes.

Retrospective cohort study comparing activated partial thromboplastin time versus anti-factor Xa activity nomograms for therapeutic unfractionated heparin monitoring in pediatrics.

BACKGROUND: Unfractionated heparin (UFH) is widely used to treat thromboembolic disease, but monitoring in children is challenging. Both activated partial thromboplastin time (aPTT) and anti-factor Xa activity (anti-Xa) are utilized, but a comparison of dosing nomograms has not been reported in pediatrics. OBJECTIVE: To compare the performance of aPTT and anti-Xa for UFH monitoring in pediatric patients. DESIGN/METHODS: A retrospective cohort study was conducted in patients ≤ 21 years old treated with UFH at Johns Hopkins Hospital from January 2009 to May 2011. For monitoring, an aPTT nomogram was used for the initial 15 months, and an anti-Xa nomogram was used for the subsequent 12 months. Clinical characteristics, laboratory data and outcomes were analyzed. RESULTS: Thirty-four patients were monitored with aPTT and 26 patients with anti-Xa. There was no significant difference in median time to therapeutic range (11.6 h aPTT, 95%CI = 6.0-17.0; 9.9 h anti-Xa, 95%CI = 7.3-20.7) or per cent of patients achieving therapeutic measurements at 24 (79% aPTT, 95%CI = 62-91; 73% anti-Xa, 95%CI = 52-88) and 48 h (88% aPTT, 95%CI = 73-97; 96% anti-Xa, 95%CI = 80-100). However, anti-Xa measurements were more frequently therapeutic than aPTT (74% [95%CI = 69-78] vs. 54% [95%CI = 50-59]). Variance between anti-Xa and aPTT measurements was high (R(2)  = 0.236). No significant difference was seen in bleeding incidence (9% aPTT, 95%CI = 2-24; 15% anti-Xa, 95%CI = 4-35). CONCLUSION: The time to achieve therapeutic measures and bleeding outcomes were not significantly different between anti-Xa and aPTT nomograms. However, a small study size limits the power to detect clinically relevant differences. The results warrant larger prospective studies of UFH monitoring in children with thromboembolic disease.

Unfractionated heparin dosing for therapeutic anticoagulation in critically ill obese adults.

PURPOSE: Research evaluating unfractionated heparin (UFH) dosing in obese critically ill populations is limited. This study aimed to determine optimal weight-based and total therapeutic infusion rates of UFH in this population. METHODS: This retrospective cohort study compared adults on UFH infusions in intensive care units from May 2011 through October 2013 across 3 weight strata: 95 to 104 kg (control), 105 to 129 kg (high weight), and greater than or equal to 130 kg (higher weight). Primary outcomes included total and weight-based infusion rates for therapeutic anticoagulation. RESULTS: To achieve therapeutic activated partial thromboplastin times, higher weight patients had higher mean infusion rates compared with control (2017 vs 1582 U/h; P = .002). Mean weight-based therapeutic infusion rate was lower in the higher weight group compared with control (13.1 vs 15.8 U kg(-1) h(-1); P = .008). Post hoc analyses indicated mean weight-based infusion rate to achieve therapeutic anticoagulation was 15 U kg(-1) h(-1) in patients less than 165 kg and 13 U kg(-1) h(-1) in patients greater than 165 kg. CONCLUSIONS: Patients greater than or equal to 130 kg have lower weight-based heparin requirements compared with patients 95 to 104 kg. This difference appears to be driven by patients greater than 165 kg. Patients greater than 165 kg have lower weight-based heparin requirements, whereas patients from 105 to 164 kg have weight-based requirements similar to a normal-weight patient population. Initiating heparin at appropriate weight-based doses for obese patients may optimize anticoagulation.

Venous thromboembolism incidence in the Cooperative Study of Sickle Cell Disease.

BACKGROUND: Venous thromboembolism (VTE) has been recently recognized as a complication of sickle cell disease (SCD); however, the incidence of VTE in SCD is unknown. OBJECTIVES: The primary objective of this study was to determine the incidence of first VTE, including pulmonary embolism (PE) and deep vein thrombosis (DVT), among SCD patients age ≥ 15 years. We also evaluated genotypic differences in VTE risk and determined the relationship between VTE and mortality. PATIENTS/METHODS: In this retrospective cohort study, we used data from the Cooperative Study of Sickle Cell Disease (CSSCD) to calculate incidence rates for first VTE. We used Cox proportional hazard models to estimate hazard ratios (HRs) for time to VTE by genotype and time to death by VTE status. RESULTS: We included 1523 SCD patients aged ≥ 15 years with 8862 years of follow-up in this analysis. The incidence rate for first VTE was 5.2 events/1000 person-years (95% confidence interval [CI] 3.8-6.9) with a cumulative incidence of 11.3% (95% CI 8.3-15.3) by age 40 years. Individuals with the SS/Sß(0) -thalassemia genotype had the highest rate of VTE (7.6 events/1000 person-years [95% CI 5.3-10.6]). The incidence of PE exceeded that of isolated DVT (3.6 [95% CI 2.5-5.1] events/1000 person-years vs. 1.6 [95% CI 0.9-2.7] events/1000 person-years), although this difference was not statistically significant. SCD patients with VTE had a higher mortality rate (adjusted HR 2.32 [95% CI 1.20-4.46]) than those without VTE. CONCLUSIONS: Patients with SCD are at substantial risk for VTE, and individuals with VTE are at higher risk of death than those without VTE.

Eculizumab prevents recurrent antiphospholipid antibody syndrome and enables successful renal transplantation.

Renal transplantation in patients with antiphospholipid antibodies has historically proven challenging due to increased risk for thrombosis and allograft failure. This is especially true for patients with antiphospholipid antibody syndrome (APS) and its rare subtype, the catastrophic antiphospholipid antibody syndrome (CAPS). Since a critical mechanism of thrombosis in APS/CAPS is one mediated by complement activation, we hypothesized that preemptive treatment with the terminal complement inhibitor, eculizumab, would reduce the extent of vascular injury and thrombosis, enabling renal transplantation for patients in whom it would otherwise be contraindicated. Three patients with APS, two with a history of CAPS, were treated with continuous systemic anticoagulation together with eculizumab prior to and following live donor renal transplantation. Two patients were also sensitized to human leukocyte antigens (HLA) and required plasmapheresis for reduction of donor-specific antibodies. After follow-up ranging from 4 months to 4 years, all patients have functioning renal allografts. No systemic thrombotic events or early graft losses were observed. While the appropriate duration of treatment remains to be determined, this case series suggests that complement inhibitors such as eculizumab may prove to be effective in preventing the recurrence of APS after renal transplantation.

International clinical practice guidelines for the treatment and prophylaxis of venous thromboembolism in patients with cancer.

BACKGROUND: Guidelines addressing the management of venous thromboembolism (VTE) in cancer patients are heterogeneous and their implementation has been suboptimal worldwide. OBJECTIVES: To establish a common international consensus addressing practical, clinically relevant questions in this setting. METHODS: An international consensus working group of experts was set up to develop guidelines according to an evidence-based medicine approach, using the GRADE system. RESULTS: For the initial treatment of established VTE: low-molecular-weight heparin (LMWH) is recommended [1B]; fondaparinux and unfractionated heparin (UFH) can be also used [2D]; thrombolysis may only be considered on a case-by-case basis [Best clinical practice (Guidance)]; vena cava filters (VCF) may be considered if contraindication to anticoagulation or pulmonary embolism recurrence under optimal anticoagulation; periodic reassessment of contraindications to anticoagulation is recommended and anticoagulation should be resumed when safe; VCF are not recommended for primary VTE prophylaxis in cancer patients [Guidance]. For the early maintenance (10 days to 3 months) and long-term (beyond 3 months) treatment of established VTE, LMWH for a minimum of 3 months is preferred over vitamin K antagonists (VKA) [1A]; idraparinux is not recommended [2C]; after 3-6 months, LMWH or VKA continuation should be based on individual evaluation of the benefit-risk ratio, tolerability, patient preference and cancer activity [Guidance]. For the treatment of VTE recurrence in cancer patients under anticoagulation, three options can be considered: (i) switch from VKA to LMWH when treated with VKA; (ii) increase in LMWH dose when treated with LMWH, and (iii) VCF insertion [Guidance]. For the prophylaxis of postoperative VTE in surgical cancer patients, use of LMWH o.d. or low dose of UFH t.i.d. is recommended; pharmacological prophylaxis should be started 12-2 h preoperatively and continued for at least 7-10 days; there are no data allowing conclusion that one type of LMWH is superior to another [1A]; there is no evidence to support fondaparinux as an alternative to LMWH [2C]; use of the highest prophylactic dose of LMWH is recommended [1A]; extended prophylaxis (4 weeks) after major laparotomy may be indicated in cancer patients with a high risk of VTE and low risk of bleeding [2B]; the use of LMWH for VTE prevention in cancer patients undergoing laparoscopic surgery may be recommended as for laparotomy [Guidance]; mechanical methods are not recommended as monotherapy except when pharmacological methods are contraindicated [2C]. For the prophylaxis of VTE in hospitalized medical patients with cancer and reduced mobility, we recommend prophylaxis with LMWH, UFH or fondaparinux [1B]; for children and adults with acute lymphocytic leukemia treated with l-asparaginase, depending on local policy and patient characteristics, prophylaxis may be considered in some patients [Guidance]; in patients receiving chemotherapy, prophylaxis is not recommended routinely [1B]; primary pharmacological prophylaxis of VTE may be indicated in patients with locally advanced or metastatic pancreatic [1B] or lung [2B] cancer treated with chemotherapy and having a low risk of bleeding; in patients treated with thalidomide or lenalidomide combined with steroids and/or chemotherapy, VTE prophylaxis is recommended; in this setting, VKA at low or therapeutic doses, LMWH at prophylactic doses and low-dose aspirin have shown similar effects; however, the efficacy of these regimens remains unclear [2C]. Special situations include brain tumors, severe renal failure (CrCl<30 mL min(-1) ), thrombocytopenia and pregnancy. Guidances are provided in these contexts. CONCLUSIONS: Dissemination and implementation of good clinical practice for the management of VTE, the second cause of death in cancer patients, is a major public health priority.

International clinical practice guidelines for the treatment and prophylaxis of thrombosis associated with central venous catheters in patients with cancer.

BACKGROUND: Although long-term indwelling central venous catheters (CVCs) may lead to pulmonary embolism (PE) and loss of the CVC, there is lack of consensus on management of CVC-related thrombosis (CRT) in cancer patients and heterogeneity in clinical practices worldwide. OBJECTIVES: To establish common international Good Clinical Practices Guidelines (GCPG) for the management of CRT in cancer patients. METHODS: An international working group of experts was set up to develop GCPG according to an evidence-based medicine approach, using the GRADE system. RESULTS: For the treatment of established CRT in cancer patients, we found no prospective randomized studies, two non-randomized prospective studies and one retrospective study examining the efficacy and safety of low-molecular-weight heparin (LMWH) plus vitamin K antagonists (VKAs). One retrospective study evaluated the benefit of CVC removal and two small retrospective studies were on thrombolytic drugs. For the treatment of symptomatic CRT, anticoagulant treatment (AC) is recommended for a minimum of 3 months; in this setting, LMWHs are suggested. VKAs can also be used, in the absence of direct comparisons of these two types of anticoagulants in this setting [Guidance]. The CVC can be kept in place if it is functional, well-positioned and non-infected and there is good resolution under close surveillance; whether the CVC is kept or removed, no standard approach in terms of AC duration has been established [Guidance]. For the prophylaxis of CRT in cancer patients, we found six randomized studies investigating the efficacy and safety of VKA vs. placebo or no treatment, one on the efficacy and safety of unfractionnated heparin, six on the value of LMWH, one double-blind randomized and one non randomized study on thrombolytic drugs and six meta-analyses of AC and CVC thromboprophylaxis. Type of catheter (open-ended like the Hickman(®) catheter vs. closed-ended catheter with a valve like the Groshong(®) catheter), its position (above, below or at the junction of the superior vena cava and the right atrium) and method of placement may influence the onset of CRT on the basis of six retrospective trials, four prospective non-randomized trials, three randomized trials and one meta-analysis. In light of these data: use of AC for routine prophylaxis of CRT is not recommended [1A]; a CVC should be inserted on the right side, in the jugular vein, and distal extremity of the CVC should be located at the junction of the superior vena cava and the right atrium [1A]. CONCLUSION: Dissemination and implementation of these international GCPG for the prevention and treatment of CRT in cancer patients at each national level is a major public health priority, needing worldwide collaboration.

Novel analysis of clinically relevant diagnostic errors in point-of-care devices.

BACKGROUND: To ensure proper clinical decision-making and avoid preventable harm, the quality of point-of-care (POC) device measures is routinely assessed. Traditional analyses may not reveal clinically important diagnostic errors. OBJECTIVES: To compare results between a novel analytic framework and traditional analyses. METHODS: Patients in four anticoagulation clinics provided two measures of the International Normalized Ratio (INR) at the same visit as part of routine quality assurance: one via a venous sample and one fingerstick. These were assessed with Hemochron POC devices. Traditional, quarterly, quality assurance assessments emphasized correlation analysis. The novel analysis used enhanced graphics and a validated assessment of clinical decision-making. RESULTS: 1518 paired INRs were analyzed. The correlation between the POC and laboratory assessments ranged between 0.84 and 0.91. Traditional quality assurance showed that the Hemochron devices were acceptable for continued use in each quarterly analysis. Enhanced graphical analysis demonstrated that the Hemochron devices never reported seven common INR values. The Hemochron devices systematically inflated values < 3 and deflated values > 4, biasing results towards the target INR range. Consequently, the Hemochron devices lead to a different clinical decision than the clinical laboratory measure in 31% of cases (458/1466; 95% confidence interval [CI] 29-34). When the reference INR was low, the Hemochron devices would not result in appropriate dose increases in 52% of cases (95% CI 48-56), placing these patients at risk for a significant adverse drug event. CONCLUSIONS: Our novel, clinically relevant analysis revealed previously undetected deficiencies in our POC INR devices, and our approach should be adopted by industry, regulators, and institutions.

Clinical decision-making as the basis for assessing agreement between measures of the International Normalized Ratio.

BACKGROUND: The now classic approach of Bland and Altman is often used to assess the level of agreement between International Normalized Ratio (INR) measures. However, we are concerned that this method does not define agreement in a clinically meaningful way. Agreement between measures should be characterized explicitly in terms of clinical decisions that result from INR measures. OBJECTIVES: To develop and validate an extension of the Bland-Altman method to assess agreement between INR measures, based explicitly on the way clinicians make decisions. METHODS AND RESULTS: We developed a clinically based graphical method to estimate the level of agreement between measures of INR. We identified clinically relevant INR ranges using epidemiologic and clinical evidence regarding risk and expected outcome at different INR ranges. Clinical decisions were expected to agree within these INR ranges and, therefore, the ranges became the basis for establishing agreement between measures. We used paired INR measures and resultant clinical decisions measured during a previous prospective study to validate and compare the accuracy of our model to those of Bland and Altman's and other published models. Our method more accurately predicts when warfarin dosing decisions differ than the Bland-Altman method (P < 0.02). Our method is also superior to other published methods, particularly at the important task of identifying when measures lead to discrepant clinical decisions. CONCLUSIONS: We introduced and validated an improvement of the Bland-Altman method to assess agreement between INR measures. Our model is superior because it is based explicitly on factors that influence clinical decision-making.

The chemokine receptor Cxcr3 is not essential for acute cardiac allograft rejection in mice and rats.

Chemokine receptors have gained attention as potential targets for novel therapeutic strategies. We investigated the mechanisms of allograft rejection in chemokine receptor Cxcr3-deficient mice using a model of acute heart allograft rejection in the strain combination BALB/c to C57BL/6. Allograft survival was minimally prolonged in Cxcr3-deficient mice compared to wild-type (wt) animals (8 vs. 7 days) and treatment with a subtherapeutic dose of cyclosporine A (CsA) led to similar survival in Cxcr3-deficient and wt recipients (13 vs. 12 days). At rejection grafts were histologically indistinguishable. Microarray analysis revealed that besides Cxcr3 only few genes were differentially expressed in grafts or in spleens from transplanted or untransplanted animals. Transcript analysis by quantitative RT-PCR of selected cytokines, chemokines, or chemokine receptors or serum levels of selected cytokines and chemokines showed similar levels between the two groups. Furthermore, in a rat heart allograft transplantation model treatment with a small molecule CXCR3 antagonist did not prolong survival despite full blockade of Cxcr3 in vivo. In summary, Cxcr3 deficiency or pharmacologic blockade does not diminish graft infiltration, tempo and severity of rejection. Thus, Cxcr3 does not appear to play a pivotal role in the allograft rejection models described here.

Treatment of venous thromboembolism with low-molecular-weight heparin: a synthesis of the evidence published in systematic literature reviews.

OBJECTIVE: To evaluate the methodology and cumulative evidence presented in systematic reviews of clinical trials comparing low-molecular-weight heparin (LMWH) with unfractionated heparin (UFH) for the treatment of venous thromboembolism. METHODS: We reviewed all systematic reviews of clinical trials published until March 2002. Fourteen systematic literature reviews were published between 1994 and 2000. Deficiencies in methodological quality were common, particularly in the description of search strategies, assessment of clinical trial quality, and methods used to combine results. RESULTS: Results of reviews indicate that LMWH is superior to UFH for the treatment of venous thromboembolism, particularly in reducing mortality. Patients with isolated deep venous thrombosis or deep venous thrombosis with concomitant pulmonary embolism seemed to have similar benefit. However, the benefits of LMWH over UFH were smaller in magnitude in reviews that included more recent clinical trials.

A mail survey of United States hematologists and oncologists: a comparison of business reply versus stamped return envelopes.

Mailed surveys are a popular means of obtaining data on large populations. In July 1999 a mail survey was conducted among 3000 randomly selected members of the American Society of Hematology to assess their approach to diagnosis and treatment of polycythemia vera. Because the researchers and the study population are members of the same professional organization with a vested interest in the results, we anticipated that the advantages of return stamped postage seen in previous studies would be less significant. The response rate for stamped return envelopes was 38% versus 32% for business reply envelopes. This statistically significant difference (P =.0005) of six percentage points is comparable to previous research. Excluding labor, the total cost per returned survey was $2.62 for business reply envelopes versus $1.82 for stamped return envelopes. We conclude that stamped return envelopes are a more effective and cost-efficient means of procuring data from physician specialists.

Von Willebrand factor-cleaving protease activity and proteolysis of von Willebrand factor in bone marrow transplant-associated thrombotic microangiopathy.

INTRODUCTION: Thrombotic microangiopathy (TM) of the fulminant type occurring in patients following bone marrow transplant (BMT) has clinical manifestations that are similar to thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome, but the outcome is generally fatal despite conventional therapy. Idiopathic acquired TTP has been associated with IgG inhibitors to the cleaving protease of von Willebrand factor (vWF) in plasma. In this study, we investigated the role of the vWF protease and vWF proteolysis in the pathogenesis of BMT-associated TM of the fulminant type. METHODS: vWF antigen level, vWF multimeric pattern, and vWF metalloprotease activity were investigated in the plasma samples of six consecutive patients with acute BMT-associated TM. Histologic and immunohistochemical studies were also performed on autopsy kidney specimens from four of the patients. All six patients had the fulminant type of the disorder with a fatal outcome and none of the patients responded to plasma infusion. RESULTS: The vWF-cleaving protease activity in plasma was normal in all patients. However, analysis of the vWF multimeric pattern showed a decrease of high molecular weight multimers. The decrease of large multimers may be caused by vWF-platelet binding as well as shear enhanced proteolysis of vWF. In the four patients who had an autopsy, a pattern of arteriolar thrombosis, distinct from that of TTP, was detected in the kidneys. CONCLUSION: These findings suggest that BMT-associated TM of the fulminant type is a heterogeneous process and distinct from TTP in pathogenesis. Analysis of vWF protease and vWF multimeric distribution are valuable tools in making the distinction between BMT-associated TM and TTP.

Vena caval filters: a comprehensive review.

Hematologists are often asked to treat patients with venous thromboembolic disease. Although anticoagulation remains the primary therapy for venous thromboembolism, vena caval filters are an important alternative when anticoagulants are contraindicated. To assess the evidence supporting the utility of these devices, a comprehensive review of the English language literature was performed. Except for one randomized trial, the vena caval filter literature consists of case series or consecutive case series. The mean duration of follow-up for each of the 5 filter types varies from 6 to 18 months. All are about equally effective in the prevention of pulmonary embolism (2.6%-3.8%). Deep venous thrombosis (6%-32%) and inferior vena cava thrombosis (3.6%-11.2%) after filter placement vary widely among different filter types primarily because of differences in outcome assessment. Thrombosis at the insertion site is a common complication of filter placement (23%-36%). In view of the absence of randomized comparisons, no filter can be designated as superior in safety or efficacy. Vena caval filters represent a potentially important but poorly evaluated therapeutic modality in the prevention of pulmonary emboli. Randomized trials are necessary to establish the appropriate place for vena caval filters in the treatment of venous thromboembolic disease. (Blood. 2000;95:3669-3677)

Immunocytochemical localization of alpha2,3(N)-sialyltransferase (ST3Gal III) in cell lines and rat kidney tissue sections: evidence for golgi and post-golgi localization.

Sialylation is a biosynthetic process occurring in the trans compartments of the Golgi apparatus. Corresponding evidence is based on localization and biochemical studies of alpha2, 6(N)-sialyltransferase (ST6Gal I) as previously reported. Here we describe generation and characterization of polyclonal antibodies to recombinant rat alpha2,3(N)-sialyltransferase (ST3Gal III) expressed as a soluble enzyme in Sf9 cells or as a beta-galactosidase-human-ST3Gal III fusion-protein from E.coli , respectively. These antibodies were used to localize ST3Gal III by immunofluorescence in various cell lines and rat kidney tissue sections. In transiently transfected COS cells the antibodies directed to soluble sialyltransferase or the sialyltransferase portion of the fusion-protein only recognized the recombinant antigen retained in the endoplasmic reticulum. However, an antibody fraction crossreactive with beta-galactosidase recognized natively expressed ST3Gal III which was found to be colocalized with beta1, 4-galactosyltransferase in the Golgi apparatus of several cultured cell lines. Antibodies affinity purified on the beta-galactosidase-ST3Gal III fusion-protein column derived from both antisera have then been used to localize the enzyme in perfusion-fixed rat kidney sections. We found strong staining of the Golgi apparatus of tubular epithelia and a brush-border-associated staining which colocalized with cytochemical staining of the H+ATPase. This subcellular localization was not observed for ST6Gal I which localized to the Golgi apparatus. These data show colocalization in the Golgi apparatus and different post-Golgi distributions of the two sialyltransferases.

Cloning of a human UDP-galactose:2-acetamido-2-deoxy-D-glucose 3beta-galactosyltransferase catalyzing the formation of type 1 chains.

Biochemical evidence suggests that the galactosyltransferase activity synthesizing type 1 carbohydrate chains is separate from the well characterized enzyme that is responsible for the synthesis of type 2 chains. This was recently confirmed by the cloning, from melanoma cells, of an enzyme capable of synthesizing type 1 chains, which was shown to have no homology to other galactosyltransferases. We report here the molecular cloning and functional expression of a second human beta3-galactosyltransferase distinct from the melanoma enzyme. The new beta3-galactosyltransferase has homology to the melanoma enzyme in the putative catalytic domain, but has longer cytoplasmic and stem regions and a carboxyl-terminal extension. Northern blots showed that the new gene is present primarily in brain and heart. When transfected into mammalian cells, this gene directs the synthesis of type 1 chains as determined by a monoclonal antibody specific for sialyl Lewisa. A soluble version of the cloned enzyme was expressed in insect cells and purified. The soluble enzyme readily catalyzes the transfer of galactose to GlcNAc to form Gal(beta1-3)GlcNAc. It also has a minor but distinct transfer activity toward Gal, LacNAc, and lactose, but is inactive toward GalNAc.