Hematology

Von Willebrand Disease in the Netherlands (Doctoral Thesis)

Wee, E.M. de — 2011-10-26T00:00:00Z

Based on previous epidemiologic studies it is estimated that in the Netherlands the referral based prevalence of moderate to severe von Willebrand disease (VWD) is approximately 1 in 10,000 (1650 patients). This does not include patients with mild type 1 disease (VWF levels 30-50 U/dL), or individuals with borderline VWF levels with a mild bleeding phenotype, of which the prevalence is higher and may even reach 1:100 individuals. Despite the frequency of the disease only a limited number of studies have been performed on clinical presentation, determinants of bleeding phenotype and Quality of Life (QoL). Therefore we have initiated a nationwide study on moderate and severe VWD in the Netherlands, the Willebrand in the Netherlands study, the WiN study.

Prognostic value of FLT3 mutations in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and anthracycline monochemotherapy (Article)

Montesinos, P. — 2011-10-01T00:00:00Z

Background Fms-like tyrosine kinase-3 (FLT3) gene mutations are frequent in acute promyelocytic leukemia but their prognostic value is not well established. Design and Methods We evaluated FLT3-internal tandem duplication and FLT3-D835 mutations in patients treated with all-trans retinoic acid and anthracycline-based chemotherapy enrolled in two subsequent trials of the Programa de Estudio y Tratamiento de las Hemopatías Malignas (PETHEMA) and Hemato-Oncologie voor Volwassenen Nederland (HOVON) groups between 1996 and 2005. Results FLT3-internal tandem duplication and FLT3-D835 mutation status was available for 306 (41%) and 213 (29%) patients, respectively. Sixty-eight (22%) and 20 (9%) patients had internal tandem duplication and D835 mutations, respectively. Internal tandem duplication was correlated with higher white blood cell and blast counts, lactate dehydrogenase, relapse-risk score, fever, hemorrhage, coagulopathy, BCR3 isoform, M3 variant subtype, and expression of CD2, CD34, human leukocyte antigen-DR, and CD11b surface antigens. The FLT3-D835 mutation was not significantly associated with any clinical or biological characteristic. Univariate analysis showed higher relapse and lower survival rates in patients with a FLT3-internal tandem duplication, while no impact was observed in relation to FLT3-D835. The prognostic value of the FLT3-internal tandem duplication was not retained in the multivariate analysis. Conclusions FLT3-internal tandem duplication mutations are associated with several hematologic features in acute promyelocytic leukemia, in particular with high white blood cell counts, but we were unable to demonstrate an independent prognostic value in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and anthracycline-based regimens.

Intensified alemtuzumab-CHOP therapy for peripheral T-cell lymphoma (Article)

Kluin-Nelemans, H.C. — 2011-07-04T00:00:00Z

Background: The prognosis of T-cell lymphoma is poor. To explore the addition of the monoclonal antibody alemtuzumab, we studied the efficacy and tolerability of an intensified alemtuzumab-chemotherapy combination for aggressive T-cell lymphoma in a phase II study by Dutch-Belgian Hemato-Oncology Group (HOVON). Patients and methods: Patients (≤65 years) with newly diagnosed T-cell lymphoma received eight CHOP cycles (cyclophosphamide, doxorubicin, vincristine, prednisone) 2-weekly, each cycle with three doses of 30 mg alemtuzumab. Prophylaxis consisted of cotrimoxazole, fluconazole and valaciclovir. Cytomegalovirus (CMV) monitoring took place at least every fortnight. Results: Twenty patients from 10 centers, median age 50 years, were included. Eighty-five percent received six or more cycles. The overall response was 90% [12 complete remissions (CRs), 1 CR unconfirmed, 5 partial remissions]. Median duration of follow-up of patients still alive was 29 months (range 19-41 months). Median overall survival (OS) and event-free survival (EFS) were 27 and 10 months, with 55%/27% OS/EFS at 2 years. Adverse events consisted of neutropenic fever (n = 8) and CMV reactivation (n = 7), with one CMV disease. Three patients developed secondary Epstein-Barr virus (EBV)-related lymphoma, all after end of treatment. Conclusions: Although intensified alemtuzumab-CHOP induces high responses, many patients relapse, and the scheme is associated with serious infection-related adverse events. EBV monitoring after end of treatment is required.

Relationship between thrombospondin gene variations, von Willebrand factor levels and the risk of coronary heart disease in an older population (Article)

Loon, J.E. van — 2011-07-01T00:00:00Z

Myelin ingestion alters macrophage antigen-presenting function in vitro and in vivo (Article)

Zwam, M. van — 2011-07-01T00:00:00Z

During MS, phagocytosing myelin-containing macrophages arise and lie in close proximity to T cells. To date, it has not been addressed whether these myelinladen macrophages have the capacity to present antigens to T cells and whether this contributes to inflammation in disease. We demonstrate that in vitro-generated human and mouse myelin-laden macrophages expressed MHC class I and II and costimulatory molecules and are thus well equipped for antigen presentation.uman myelin-laden macrophages exhibited normal endocytosis of particulate and soluble antigens. In addition, human myelin-laden macrophages elicited active T cell proliferation of nai{dotless}̈ve as well as memory T cells. Furthermore, mouse myelin-laden macrophages induced primary antigen-specific CD4+T cell proliferation in vivo but transiently diminished IFN-γ release. Functionally, MOG peptide-loaded myelin-laden mouse macrophages modestly but significantly reduced the severity of MOG peptide-induced EAE. These data show that myelin uptake results in the induction of a population of macrophages that retains antigen-presenting capacity and limits autoimmune-mediated disease.

Studies on Genetic Aberrations in Acute Myeloid Leukemia (Doctoral Thesis)

Abbas, S. — 2011-06-29T00:00:00Z

Hematopoiesis is the formation of blood cellular components. In mammalian embryonic development, the yolk sac and its vasculature are the source of the first blood cells called hematopoietic stem cells (HSCs) from which all blood cells originate. HSCs are produced by the aorta-gonad-mesonephros region, yolk sac and placenta from where they migrate to the fetal liver, where they expand. Hereafter, HSCs transfer to the bone marrow from where they establish the definitive adult hematopoiesis and reside throughout adulthood. HSCs are responsible for foundation of the adult blood differentiation hierarchy and provide continuous hematopoietic cell production. The major characteristic of HSCs is their self-renewal capacity, i.e., they proliferate to give rise to all different types of blood cells, but the pool of stem cells does not become depleted . HSCs are pluripotent. They generate more committed progenitor cells or other stem cells, i.e., common myeloid and lymphoid progenitor cells (CMPs and CLPs respectively) which differentiate and give rise to the progeny belonging to these two lineages of blood cells. While the lymphoid progenitor cells generate B- and T cells as well as natural killer cells, the myeloid progenitor cells produce the other leukocytes, i.e. granulocytes and monocytes/macrophages, as well as red blood cells (erythrocytes) and platelets (Figure 1). The life span of mature blood cells is relatively short and cell production process is continuous, therefore it demands tight regulation by hematopoietic growth factors. The hematopoietic growth factors are a family of cytokines that interact with specific receptors on hematopoietic cells. These molecules like stem cell factor (SCF) or KIT ligand (KIT-L), granulocyte-macrophage CSF (GM-CSF), granulocyte CSF (G-CSF), and macrophage CSF (M-CSF), regulate the functional activation of the specific cells with which they interact. Hematopoietic growth factors are required for the survival, proliferation, and differentiation of hematopoietic progenitors.

Intensified chemotherapy inspired by a pediatric regimen combined with allogeneic transplantation in adult patients with acute lymphoblastic leukemia up to the age of 40 (Article)

Rijneveld, A.W. — 2011-06-07T00:00:00Z

Event-free survival (EFS) at 5 years in pediatric acute lymphoblastic leukemia (ALL) is >80%. Outcome in adult ALL is still unsatisfactory, which is due to less cumulative dosing of chemotherapy and less strict adherence to timing of successive cycles. In the present phase II trial, we evaluated a pediatric regimen in adult patients with ALL under the age of 40. Treatment was according to the pediatric FRALLE approach for high-risk ALL patients and characterized by increased dosages of asparaginase, steroids, methotrexate and vincristin. However, allogeneic stem cell transplantation was offered to standard risk patients with a sibling donor and to all high-risk patients in contrast to the pediatric protocol. Feasibility was defined by achieving complete remission (CR) and completion of treatment within a strict timeframe in at least 60% of patients. In all, 54 patients were included with a median age of 26. CR was achieved in 49 patients (91%), of whom 33 completed treatment as scheduled (61%). Side effects primarily consisted of infections and occurred in 40% of patients. With a median follow-up of 32 months, EFS estimated 66% at 24 months and overall survival 72%. These data show that a dose-intensive pediatric regimen is feasible in adult ALL patients up to the age of 40.Leukemia advance online publication, 7 June 2011; doi:10.1038/leu.2011.141.

Functional crosstalk between Bmi1 and MLL/Hoxa9 axis in establishment of normal hematopoietic and leukemic stem cells (Article)

Smith, L.L. — 2011-06-03T00:00:00Z

Bmi1 is required for efficient self-renewal of hematopoietic stem cells (HSCs) and leukemic stem cells (LSCs). In this study, we investigated whether leukemia-associated fusion proteins, which differ in their ability to activate Hox expression, could initiate leukemia in the absence of Bmi1. AML1-ETO and PLZF-RARα, which do not activate Hox, triggered senescence in Bmi1-/-cells. In contrast, MLL-AF9, which drives expression of Hoxa7 and Hoxa9, readily transformed Bmi1-/-cells. MLL-AF9 could not initiate leukemia in Bmi1-/-Hoxa9-/-mice, which have further compromised HSC functions. But either gene could restore the ability of MLL-AF9 to establish LSCs in the double null background. As reported for Bmi1, Hoxa9 regulates expression of p16Ink4a/p19ARFlocus and could overcome senescence induced by AML1-ETO. Together, these results reveal an important functional interplay between MLL/Hox and Bmi1 in regulating cellular senescence for LSC development, suggesting that a synergistic targeting of both molecules is required to eradicate a broader spectrum of LSCs.

Activation and effector functions of human RORC+ innate lymphoid cells (Article)

Cornelissen, F.H.J. — 2011-06-01T00:00:00Z

Innate lymphoid cells expressing the nuclear hormone receptor RORC have emerged as important players in human mucosal immunity. These cells combine innate modes of activation such as Toll-like receptor signaling with secretion of adaptive effector molecules including IL-2, BAFF and the Th17 cytokines IL-17 and IL-22. This endows these cells with the ability to rapidly respond to changes in cytokine milieu as well as changes in microbial composition and to affect both intestinal homeostasis and activation of adaptive immune cells.

Human plasmacytoid dendritic cells induce CD8+LAG-3+Foxp3+CTLA-4+ regulatory T cells that suppress allo-reactive memory T cells (Article)

Boor, P.P.C. — 2011-06-01T00:00:00Z

Allo-reactive memory T cells are a major barrier for induction of immunological tolerance to allografts in humans. Here, we report that stimulation of unfractionated human T cells with TLR-stimulated allogeneic plasmacytoid dendritic cells (pDCs) induces CD8+regulatory T cells (Tregs) that inhibit T-cell allo-responses, including those of memory T cells. CD3+T cells were primed for 7 days with allogeneic pDCs that had been pre-stimulated with TLR-7 or TLR-9 ligands. While the T cells proliferated and produced cytokines during the priming culture, they were profoundly hypo-responsive to re-stimulation with the same allo-antigen in a second culture. Moreover, T cells primed by pDCs exerted donor-specific suppression on allo-responses of both unfractionated and memory CD3+T cells. The regulatory capacity of pDC-primed T cells was confined to CD8+LAG-3+Foxp3+CTLA-4+T cells, which suppressed allogeneic T-cell responses through a CTLA-4-dependent mechanism. Induction of CD8+Tregs by pDCs could be partially prevented by 1-methyl tryptophan, an inhibitor of indoleamine 2,3-dioxygenase. In conclusion, stimulation of human T cells by TLR-stimulated allogeneic pDCs induces CD8+Tregs that inhibit allogeneic T-cell responses, including memory T cells. Donor-derived pDCs may be considered as an immunotherapeutic tool to prevent activation of the recipient allo-reactive (memory) T-cell repertoire after allogeneic transplantation.

A prospective study on elective umbilical hernia repair in patients with liver cirrhosis and ascites (Article)

Eker, H.H. — 2011-06-01T00:00:00Z

Background: Patients with both cirrhosis and ascites have a 20% risk of developing umbilical hernia. A retrospective study from our center comparing conservative management of umbilical hernia with elective repair in these patients showed a significant risk of mortality as a result of hernia incarceration in conservatively treated patients. The goal of this study was to assess the safety and efficacy of elective umbilical hernia repair in these patients prospectively. Methods: Patients with liver cirrhosis and ascites presenting with an umbilical hernia were included in this study. For all patients, the expected time to liver transplantation was more than 3 months, and they did not have a patent umbilical vein in the hernia sac. The following data were collected prospectively for all patients: Child-Pugh-Turcotte (CPT) classification, model for end-stage liver disease (MELD) score, kidney failure, cardiovascular comorbidity, operation-related complications, and duration of hospital stay. Mortality rates were registered in hospital records and verified in government records during follow-up. Mortality rates were registered in hospital records and verified in government records during follow-up. On completion of the study, a retrospective survey was performed to search for any patients who met the study inclusion criteria but were left out of the study cohort. Results: In total, 30 patients (25 males) underwent operation at a mean age of 58 years (standard deviation [SD] ± 9 years). Of these 30 patients, 6 were classified as CPT grade A (20%), 19 (63%) as grade B, and 5 (17%) as grade C. The patients' median MELD score was 12 (interquartile range [IQR], 8-16). In 10 (33%) of the 30 patients hernia repair was performed with mesh. The median duration of hospital stay was 3 days (IQR, 2-4). None of the patients were admitted to the intensive care unit. Postoperative complications included pneumonia and decompensation of cirrhosis (1 case each,) resulting in prolonged hospital stay for those 2 patients. After a median follow-up period of 25 months (IQR, 14-34), 2 (7%) of the 30 patients died; neither of the deaths were attributable to the umbilical hernia repair. A total of 2 patients suffered recurrence. Conclusion: Elective umbilical hernia repair is safe and the preferred approach in cirrhotic patients with ascites.

Predictive impact of allele-matching and EBMT risk score for outcome after T-cell depleted unrelated donor transplantation in poor-risk acute leukemia and myelodysplasia (Article)

Lodewyck, T. — 2011-06-01T00:00:00Z

Many parameters predict for outcome after unrelated donor (URD) allogeneic hematopoietic stem cell transplantation (alloSCT). High-resolution HLA-matching significantly impacts outcome and also the European Group of Blood and Marrow Transplantation (EBMT) risk score, based on patient age, disease stage, donor type, time from diagnosis to SCT and gender combination, may predict for non-relapse mortality and overall survival (OS). We evaluated the individual and combined effects of allele-matching and the EBMT risk score in 327 patients with poor-risk acute leukemia or myelodysplasia, who received a T-cell depleted URD alloSCT. Matching for HLA-A, -B, -C and -DRB1 alleles (8/8 match) was associated with a 5-year OS of 40% compared with 30% for mismatched (≤7/8) pairs (P=0.02). Patients with EBMT risk scores of 1-2, 3, 4 and 5-7 had 5-year OS estimates of 53, 43, 30 and 20%, respectively (P<0.001). The favorable prognostic impact of an 8/8 donor was most pronounced if the EBMT risk score was low (1-2). Five-year OS was 74±8% vs 39±11% for fully matched patients with a low-risk EBMT score as compared with EBMT low-risk patients with ≤7/8 donors. These data underscore the importance of incorporating both the EBMT risk score and the degree of high-resolution HLA-matching in the risk assessment prior to URD alloSCT.Leukemia advance online publication, 24 May 2011; doi:10.1038/leu.2011.123.

Integrative prognostic risk score in acute myeloid leukemia with normal karyotype (Article)

Damm, F. — 2011-06-01T00:00:00Z

To integrate available clinical and molecular information for cytogenetically normal acute myeloid leukemia (CN-AML) patients into one risk score, 275 CN-AML patients from multicenter treatment trials AML SHG Hannover 0199 and 0295 and 131 patients from HOVON/SAKK protocols as external controls were evaluated for mutations/polymorphisms in NPM1, FLT3, CEBPA, MLL, NRAS, IDH1/2, and WT1. Transcript levels were quantified for BAALC, ERG, EVI1, ID1, MN1, PRAME, and WT1. Integrative prognostic risk score (IPRS) was modeled in 181 patients based on age, white blood cell count, mutation status of NPM1, FLT3-ITD, CEBPA, single nucleotide polymorphism rs16754, and expression levels of BAALC, ERG, MN1, and WT1 to represent low, intermediate, and high risk of death. Complete remission (P = .005), relapse-free survival (RFS, P < .001), and overall survival (OS, P < .001) were significantly different for the 3 risk groups. In 2 independent validation cohorts of 94 and 131 patients, the IPRS predicted different OS (P < .001) and RFS (P < .001). High-risk patients with related donors had longer OS (P = .016) and RFS (P = .026) compared with patients without related donors. In contrast, intermediate-risk group patients with related donors had shorter OS (P=.003) and RFS(P=.05). Donor availability had no impact on outcome of patients in the low-risk group. Thus, the IPRS may improve consolidation treatment stratification in CN-AML patients. Study registered at www.clinicaltrials.gov as #NCT00209833.

Pharmacogenetic studies in multiple myeloma (Doctoral Thesis)

Corthals, S.L. — 2011-05-11T00:00:00Z

Multiple myeloma (MM) is a malignant plasma cell disorder that accounts for approximately 10% of all hematologic cancers.1-2 MM is characterized by clonal proliferation of malignant plasma cells in the bone marrow, which secrete a homogeneous immunoglobulin product known as monoclonal (M) protein or paraprotein. Typical features of MM include osteolytic bone lesions, renal disease, anemia, hypercalcemia and immunodeficiency.3 The pathological development of MM is a multistep process and starts with the emergence of an asymptomatic premalignant stage of clonal plasma cell proliferation known as “monoclonal gammopathy of undetermined significance” (MGUS), occurring in about 3% of individuals above the age of 50. MGUS cells secrete monoclonal immunoglobulin (Ig) which may progress to smouldering MM and ultimately to symptomatic intramedullary and extramedullary multiple myeloma, or plasma cell leukemia; expressing the same Ig. Smouldering MM has a stable intramedullary tumor cell content of >10%, but no osteolytic lesions or other complications of malignant MM. Patients with MGUS have a risk to progress to myeloma or a related malignancy at a rate of 1% a year.4-5 The prevalence of both MGUS and MM increases markedly with age, and is slightly more common in men than in women. The incidence is about two-fold higher in African Americans than in Caucasians. The median length of survival after diagnosis is approximately 3-5 years.

Genetic determinants of von Willebrand factor levels and activity in relation to the risk of cardiovascular disease: A review (Article)

Schie, M.C. van — 2011-05-01T00:00:00Z

It is well established that high plasma von Willebrand factor (VWF) levels are associated with an increased risk of arterial thrombosis, including myocardial infarction and ischemic stroke. As plasma VWF levels are, to a large extent, genetically determined, numerous association studies have been performed to assess the effect of genetic variability in the VWF gene (VWF) on VWF antigen and activity levels, and on the risk of arterial thrombosis. Genetic variations in other regulators of VWF, including the ABO blood group, ADAMTS-13, thrombospondin-1 and the recently identified SNARE protein genes, have also been investigated. In this article, we review the current literature as exploring the associations between genetic variations and the risk of arterial thrombosis may help elucidate the role of VWF in the pathogenesis of arterial thrombosis. However, as studies frequently differ in design, population and endpoint, and are often underpowered, it remains unclear whether VWF is causally related to the occurrence of arterial thrombosis or primarily mirrors endothelial dysfunction, which predisposes to atherosclerosis and subsequent arterial thrombosis. Nevertheless, current studies provide interesting results that do not exclude the possibility of VWF as causal mediator and justify further research into the relationship between VWF and arterial thrombosis. Large prospective studies are required to further establish the role of VWF in the occurrence of arterial thrombosis.

Proteomic analysis reveals that apolipoprotein A1 levels are decreased in patients with Budd-Chiari syndrome (Article)

Talens, S. — 2011-05-01T00:00:00Z

Background & Aims: Budd-Chiari syndrome (BCS) is a rare vascular liver disorder caused by thrombosis of the hepatic veins. In some patients, no known thrombophilic factor can be identified. This study aimed to identify novel factors that might play a role in thrombosis in BCS-patients by using a proteomic approach. Methods: The abundance of plasma clot-bound proteins was compared between nine BCS-patients and nine controls by using two-dimensional difference gel electrophoresis. The protein with the most significant decrease in patients was identified by mass spectrometry. Plasma levels of this protein were measured and the results were validated in a large cohort of BCS-patients. Results: A total of 26 protein spots significantly differed (p <0.001). The spot that decreased with the highest statistical significance in patients was identified by mass spectrometry as apolipoprotein A1 (apo A1). The mean level of apo A1 in the plasma of these BCS-patients (0.74 g/L) was also significantly lower than in controls (1.45 g/L, p = 0.002). This finding was validated in a large cohort of 101 BCS-patients and 101 controls (0.97 g/L vs. 1.32 g/L, p <0.0001). There was no major correlation between plasma levels of apo A1 and various liver function tests. Conclusions: BCS-patients show decreased clot-bound protein abundance and plasma levels of apo A1. Decreased levels of apo A1 may play a role in the etiology of thrombosis in BCS-patients and possibly in other patients with venous thrombosis.

Mobilization of hepatic mesenchymal stem cells from human liver grafts (Article)

Pan, Q. — 2011-05-01T00:00:00Z

Extensive studies have demonstrated the potential applications of bone marrow-derived mesenchymal stem cells (BM-MSCs) as regenerative or immunosuppressive treatments in the setting of organ transplantation. The aims of the present study were to explore the presence and mobilization of mesenchymal stem cells (MSCs) in adult human liver grafts and to compare their functional capacities to those of BM-MSCs. The culturing of liver graft preservation fluids (perfusates) or end-stage liver disease tissues resulted in the expansion of MSCs. Liver-derived mesenchymal stem cells (L-MSCs) were equivalent to BM-MSCs in adipogenic and osteogenic differentiation and in wingless-type-stimulated proliferative responses. Moreover, the genome-wide gene expression was very similar, with a 2-fold or greater difference found in only 82 of the 32,321 genes (0.25%). L-MSC differentiation into a hepatocyte lineage was demonstrated in immunodeficient mice and in vitro by the ability to support a hepatitis C virus infection. Furthermore, a subset of engrafted MSCs survived over the long term in vivo and maintained stem cell characteristics. Like BM-MSCs, L-MSCs were found to be immunosuppressive; this was shown by significant inhibition of T cell proliferation. In conclusion, the adult human liver contains an MSC population with a regenerative and immunoregulatory capacity that can potentially contribute to tissue repair and immunomodulation after liver transplantation.

The JAK2 46/1 haplotype in Budd-Chiari syndrome and portal vein thrombosis (Article)

Smalberg, J.H. — 2011-04-14T00:00:00Z

The germline JAK2 46/1 haplotype has been associated with the development of JAK2V617F-positive as well as JAK2V617F-negative myeloproliferative neoplasms (MPNs). In this study we examined the role of the 46/1 haplotype in the etiology and clinical presentation of patients with splanchnic vein thrombosis (SVT), in which MPNs are the most prominent underlying etiological factor. The singlenucleotide polymorphism rs12343867, which tags 46/1, was genotyped in 199 SVT patients. The 46/1 haplotype was overrepresented in JAK2V617F-positive SVT patients compared with controls (P<.01). Prevalence of the 46/1 haplotype in JAK2V617F-negative SVT patients did not differ from prevalence in the controls. However, JAK2V617F-negative SVT patients with a proven MPN also exhibited an increased frequency of the 46/1 haplotype (P =.06). Interestingly, 46/1 was associated with increased erythropoiesis in JAK2V617F-negative SVT patients. We conclude that the 46/1 haplotype is associated with the development of JAK2V617F-positive SVT. In addition, our findings in JAK2V617F-negative SVT patients indicate an important role for the 46/1 haplotype in the etiology and diagnosis of SVT-related MPNs, independent of JAK2V617F, that requires further exploration.

Truncating the i-leader open reading frame enhances release of human adenovirus type 5 in glioma cells (Article)

Hengel, S.K. — 2011-04-13T00:00:00Z

Background: The survival of glioma patients with the current treatments is poor. Early clinical trails with replicating adenoviruses demonstrated the feasibility and safety of the use of adenoviruses as oncolytic agents. Antitumor efficacy has been moderate due to inefficient virus replication and spread. Previous studies have shown that truncation of the adenovirus i-leader open reading frame enhanced cytopathic activity of HAdV-5 in several tumor cell lines. Here we report the effect of an i-leader mutation on the cytopathic activity in glioma cell lines and in primary high-grade glioma cell cultures. Results: A mutation truncating the i-leader open reading frame was created in a molecular clone of replication-competent wild-type HAdV-5 by site-directed mutagenesis. We analyzed the cytopathic activity of this RL-07 mutant virus. A cell-viability assay showed increased cytopathic activity of the RL-07 mutant virus on U251 and SNB19 glioma cell lines. The plaque sizes of RL-07 on U251 monolayers were seven times larger than those of isogenic control viruses. Similarly, the cytopathic activity of the RL-07 viruses was strongly increased in six primary high-grade glioma cell cultures. In glioma cell lines the RL-07 virus was found to be released earlier into the culture medium. This was not due to enhanced viral protein synthesis, as was evident from equivalent E1A, Fiber and Adenovirus Death Protein amounts, nor to higher virus yields. Conclusion: The cytopathic activity of replicating adenovirus in glioblastoma cells is increased by truncating the i-leader open reading frame. Such mutations may help enhancing the antitumor cytopathic efficacy of oncolytic adenoviruses in the treatment of glioblastoma.

19. Carpal Tunnel Syndrome (Article)

Patijn, J. — 2011-04-06T00:00:00Z

Carpal tunnel syndrome (CTS) is a common disorder. In the majority of cases, patients with CTS can be diagnosed by means of appropriate history taking. Nerve conduction examination of the nervus medianus is the most important additional diagnostic test and is the best predictor of symptom severity and functional status in idiopathic CTS. Treatment option depends on the severity of the symptoms and the degree of functional daily limitations. If few limitations are present, splinting or corticosteroid injections are preferred. Surgical interventions are reserved for the more severe conditions resulting in significant disability. Interventional pain treatment such as pulsed radiofrequency could be an addition to the future treatment options for CTS.Pain Practice