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1005 Publications visible to you, out of a total of 1005
Promoter methylation and expression of MGMT and the DNA mismatch repair genes MLH1, MSH2, MSH6 and PMS2 in paired primary and recurrent glioblastomas.
GGN - German Glioma Network

Abstract (Expand)

Epigenetic silencing of the O(6) -methylguanine-DNA methyltransferase (MGMT) gene promoter is associated with prolonged survival in glioblastoma patients treated with temozolomide (TMZ). We investigated … whether glioblastoma recurrence is associated with changes in the promoter methylation status and the expression of MGMT and the DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6 and PMS2 in pairs of primary and recurrent glioblastomas of 80 patients, including 64 patients treated with radiotherapy and TMZ after the first operation. Among the primary tumors, the MGMT promoter was methylated in 31 patients and unmethylated in 49 patients. In 71 patients (89%), the MGMT promoter methylation status of the primary tumor was retained at recurrence. MGMT promoter methylation, but not MGMT protein expression, was associated with longer progression-free survival, overall survival and postrecurrence survival (PRS). Moreover, PRS was increased under salvage chemotherapy. Investigation of primary and recurrent glioblastomas of 43 patients did not identify promoter methylation in any of the four MMR genes. However, recurrent glioblastomas demonstrated significantly lower MSH2, MSH6 and PMS2 protein expression as detected by immunohistochemistry. In conclusion, reduced expression of MMR proteins, but not changes in MGMT promoter methylation, is characteristic of glioblastomas recurring after the current standards of care.

Authors: J. Felsberg, N. Thon, S. Eigenbrod, B. Hentschel, M. C. Sabel, M. Westphal, G. Schackert, F. W. Kreth, T. Pietsch, M. Loffler, M. Weller, G. Reifenberger, J. C. Tonn

Date Published: 1st Aug 2011

Publication Type: Not specified

Human Diseases: glioblastoma multiforme

Circulating Nampt and RBP4 levels in patients with carotid stenosis undergoing carotid endarterectomy (CEA)
Genetical Statistics and Systems Biology

Abstract (Expand)

BACKGROUND\backslashr\backslashnObesity is a risk factor for atherosclerotic vascular disease. Altered adipokine secretion, including increased production of nicotinamide phosphoribosyltransferase … (Nampt) and retinol binding protein 4 (RBP4) may link adipose tissue dysfunction to cardiovascular complications.\backslashr\backslashnMETHODS\backslashr\backslashnWe determined Nampt and RBP4 serum concentrations in 193 consecutive patients with carotid stenosis prior to carotid endarterectomy (CEA) in relation to recently experienced ischemic events, markers of atherosclerosis and obesity, as well as anthropometric and clinical characteristics.\backslashr\backslashnRESULTS\backslashr\backslashnNampt but not RBP4 was significantly higher in symptomatic patients who experienced an ischemic event within 6 months before surgery compared to asymptomatic patients (p=0.001). In multivariate regression analysis Nampt was the only independent predictor of symptomatic carotid stenosis. Nampt correlated with peripheral leukocyte blood count (p\textless0.0001) and with the number of macrophages/foam cells within carotid plaques (p=0.042). However, Nampt and RBP4 serum concentrations did not correlate with the maximum percentage of carotid stenosis.\backslashr\backslashnCONCLUSION\backslashr\backslashnOur data suggest circulating Nampt as an independent predictor of recently experienced ischemic events in patients with carotid stenosis despite the lack of an association between Nampt and carotid atherosclerosis severity. BACKGROUND Obesity is a risk factor for atherosclerotic vascular disease. Altered adipokine secretion, including increased production of nicotinamide phosphoribosyltransferase (Nampt) and retinol binding protein 4 (RBP4) may link adipose tissue dysfunction to cardiovascular complications. METHODS We determined Nampt and RBP4 serum concentrations in 193 consecutive patients with carotid stenosis prior to carotid endarterectomy (CEA) in relation to recently experienced ischemic events, markers of atherosclerosis and obesity, as well as anthropometric and clinical characteristics. RESULTS Nampt but not RBP4 was significantly higher in symptomatic patients who experienced an ischemic event within 6 months before surgery compared to asymptomatic patients (p=0.001). In multivariate regression analysis Nampt was the only independent predictor of symptomatic carotid stenosis. Nampt correlated with peripheral leukocyte blood count (p\textless0.0001) and with the number of macrophages/foam cells within carotid plaques (p=0.042). However, Nampt and RBP4 serum concentrations did not correlate with the maximum percentage of carotid stenosis. CONCLUSION Our data suggest circulating Nampt as an independent predictor of recently experienced ischemic events in patients with carotid stenosis despite the lack of an association between Nampt and carotid atherosclerosis severity.

Authors: Gabriela Aust, Migle Uptaite-Patapoviene, Markus Scholz, Olaf Richter, Silvio Rohm, Matthias Blüher

Date Published: 1st Jun 2011

Publication Type: Journal article

Increased CD64 expression on polymorphonuclear neutrophils indicates infectious complications following solid organ transplantation
Genetical Statistics and Systems Biology

Abstract (Expand)

The aim of this study was to evaluate the diagnostic value of monitoring CD64 antigen upregulation on polymorphonuclear neutrophils (PMN) for the identification of infectious complications in the … postoperative course of solid organ transplanted patients. Twenty-five kidney, 13 liver, and four pancreas-kidney transplanted patients were included. Beginning with preoperative values up to postoperative values after 3 months for each patient, the PMN CD64 Index, HLA-DR on monocytes, NKp44+ NK and NK/T cells, CXCR3+ NK cells, CXCR3+ T helper cells, CXCR3+ NK/T cells, and CD4/CD8 ratio were measured by flow cytometry. Subsequently they were correlated with confirmed postoperative complications. Measuring the PMN CD64 Index reached a sensitivity of 89% and a specificity of 65% in the detection of infectious complications. Concerning this matter, it was a significantly better marker than all other included parameters except CXCR3+ NK/T cells. In contrast, according to our results the PMN CD64 Index has no diagnostic relevance in detection of rejections. The combination of included parameters showed no improved diagnostic value. Due to its high sensitivity and specificity for infectious complications CD64 on PMN could be proven a very good indicator in evaluating suspected infectious complications in the postoperative course of transplanted patients. The aim of this study was to evaluate the diagnostic value of monitoring CD64 antigen upregulation on polymorphonuclear neutrophils (PMN) for the identification of infectious complications in the postoperative course of solid organ transplanted patients. Twenty-five kidney, 13 liver, and four pancreas-kidney transplanted patients were included. Beginning with preoperative values up to postoperative values after 3 months for each patient, the PMN CD64 Index, HLA-DR on monocytes, NKp44+ NK and NK/T cells, CXCR3+ NK cells, CXCR3+ T helper cells, CXCR3+ NK/T cells, and CD4/CD8 ratio were measured by flow cytometry. Subsequently they were correlated with confirmed postoperative complications. Measuring the PMN CD64 Index reached a sensitivity of 89% and a specificity of 65% in the detection of infectious complications. Concerning this matter, it was a significantly better marker than all other included parameters except CXCR3+ NK/T cells. In contrast, according to our results the PMN CD64 Index has no diagnostic relevance in detection of rejections. The combination of included parameters showed no improved diagnostic value. Due to its high sensitivity and specificity for infectious complications CD64 on PMN could be proven a very good indicator in evaluating suspected infectious complications in the postoperative course of transplanted patients.

Authors: Daniel Grey, Ulrich Sack, Markus Scholz, Heike Knaack, Stephan Fricke, Christoph Oppel, Daniel Luderer, Josef Fangmann, Frank Emmrich, Manja Kamprad

Date Published: 1st Jun 2011

Publication Type: Journal article

Determination of pore size distribution at the cell-hydrogel interface.
ProstataCA

Abstract (Expand)

BACKGROUND: Analyses of the pore size distribution in 3D matrices such as the cell-hydrogel interface are very useful when studying changes and modifications produced as a result of cellular growth and … proliferation within the matrix, as pore size distribution plays an important role in the signaling and microenvironment stimuli imparted to the cells. However, the majority of the methods for the assessment of the porosity in biomaterials are not suitable to give quantitative information about the textural properties of these nano-interfaces. FINDINGS: Here, we report a methodology for determining pore size distribution at the cell-hydrogel interface, and the depth of the matrix modified by cell growth by entrapped HepG(2) cells in microcapsules made of 0.8% and 1.4% w/v alginate. The method is based on the estimation of the shortest distance between two points of the fibril-like network hydrogel structures using image analysis of TEM pictures. Values of pore size distribution determined using the presented method and those obtained by nitrogen physisorption measurements were compared, showing good agreement. A combination of these methodologies and a study of the cell-hydrogel interface at various cell culture times showed that after three days of culture, HepG(2) cells growing in hydrogels composed of 0.8% w/v alginate had more coarse of pores at depths up to 40 nm inwards (a phenomenon most notable in the first 20 nm from the interface). This coarsening phenomenon was weakly observed in the case of cells cultured in hydrogels composed of 1.4% w/v alginate. CONCLUSIONS: The method purposed in this paper allows us to obtain information about the radial deformation of the hydrogel matrix due to cell growth, and the consequent modification of the pore size distribution pattern surrounding the cells, which are extremely important for a wide spectrum of biotechnological, pharmaceutical and biomedical applications.

Authors: A. Leal-Egana, U. D. Braumann, A. Diaz-Cuenca, M. Nowicki, A. Bader

Date Published: 27th May 2011

Publication Type: Not specified

Intracranial hemangiopericytoma: Case study with cytogenetics and genome wide SNP-A analysis
Genetical Statistics and Systems Biology

Abstract (Expand)

The tumor entity of hemangiopericytoma is not universally recognized as a nosological entity by pathologists, and there is a trend toward reassigning it to other categories gradually. However, … hemangiopericytomas occurring in the nervous system are included in the new WHO classification of brain tumors, and are distinguished from both meningioma and fibrous tumors. Since there are few genetic studies, we performed a comprehensive cytogenetic analysis of an infratentorial hemangiopericytoma in a 55-year-old female. It was originally classified as a grade II tumor but recurred as a grade III tumor with a proliferation index of 20%. Using trypsin-Giemsa staining (GTG-banding) and multicolor fluorescence in situ hybridization (M-FISH), we could confirm the loss of chromosomal material 10q, which has been previously described in hemangiopericytoma, and we identified de novo chromosomal aberrations on chromosome 8. Applying genome-wide high-density single nucleotide polymorphism array (SNP-A) analysis, we detected segments with loss or gain, as well as clonal deletions or regions suggestive of segmental uniparental disomy. These findings, together with the results of conventional histological and immunohistochemical characterization, provide additional evidence for the nosological separation of hemangiopericytoma in the central nervous system as a biologically different entity.

Authors: Heidrun Holland, Michela Livrea, Peter Ahnert, Ronald Koschny, Holger Kirsten, Jürgen Meixensberger, Manfred Bauer, Ralf Schober, Dominik Fritzsch, Wolfgang Krupp

Date Published: 1st May 2011

Publication Type: Journal article

Influence of low dose irradiation on differentiation, maturation and T-cell activation of human dendritic cells
Genetical Statistics and Systems Biology

Abstract (Expand)

Ionizing irradiation could act directly on immune cells and may induce bystander effects mediated by soluble factors that are released by the irradiated cells. This is the first study analyzing both … the direct effect of low dose ionizing radiation (LDIR) on the maturation and cytokine release of human dendritic cells (DCs) and the functional consequences for co-cultured T-cells. We showed that irradiation of DC-precursors in vitro does not influence surface marker expression or cytokine profile of immature DCs nor of mature DCs after LPS treatment. There was no difference of single dose irradiation versus fractionated irradiation protocols on the behavior of the mature DCs. Further, the low dose irradiation did not change the capacity of the DCs to stimulate T-cell proliferation. But the irradiation of the co-culture of DCs and T-cells revealed significantly lower proliferation of T-cells with higher doses. Summarizing the data from approx. 50 DC preparations there is no significant effect of low dose ionizing irradiation on the cytokine profile, surface marker expression and maturation of DCs in vitro although functional consequences cannot be excluded. Ionizing irradiation could act directly on immune cells and may induce bystander effects mediated by soluble factors that are released by the irradiated cells. This is the first study analyzing both the direct effect of low dose ionizing radiation (LDIR) on the maturation and cytokine release of human dendritic cells (DCs) and the functional consequences for co-cultured T-cells. We showed that irradiation of DC-precursors in vitro does not influence surface marker expression or cytokine profile of immature DCs nor of mature DCs after LPS treatment. There was no difference of single dose irradiation versus fractionated irradiation protocols on the behavior of the mature DCs. Further, the low dose irradiation did not change the capacity of the DCs to stimulate T-cell proliferation. But the irradiation of the co-culture of DCs and T-cells revealed significantly lower proliferation of T-cells with higher doses. Summarizing the data from approx. 50 DC preparations there is no significant effect of low dose ionizing irradiation on the cytokine profile, surface marker expression and maturation of DCs in vitro although functional consequences cannot be excluded.

Authors: Jutta Jahns, Ulf Anderegg, Anja Saalbach, Britt Rosin, Ina Patties, Annegret Glasow, Manja Kamprad, Markus Scholz, Guido Hildebrandt

Date Published: 1st May 2011

Publication Type: Journal article

Monitoring of WT1 expression in PB and CD34(+) donor chimerism of BM predicts early relapse in AML and MDS patients after hematopoietic cell transplantation with reduced-intensity conditioning
Genetical Statistics and Systems Biology

Abstract (Expand)

Relapse of malignant disease remains the major complication in patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) after hematopoietic cell transplantation (HCT) with … reduced-intensity conditioning (RIC). In this study, we investigated the predictive value of disease-specific markers (DSMs), donor chimerism (DC) analysis of unsorted (UDC) or CD34(+) sorted cells and Wilms’ tumor gene 1 (WT1) expression. Eighty-eight patients with AML or MDS were monitored after allogenic HCT following 2 Gy total-body irradiation with (n=84) or without (n=4) fludarabine 3 \times 30 mg/m(2), followed by cyclosporin A and mycophenolate mofetil. DSMs were determined by fluorescence in situ hybridization (FISH) and WT1 expression by real-time polymerase chain reaction. Chimerism analysis was performed on unsorted or CD34(+) sorted cells, by FISH or short tandem repeat polymerase chain reaction. Twenty-one (24%) patients relapsed within 4 months after HCT. UDC, CD34(+) DC and WT1 expression were each significant predictors of relapse with sensitivities ranging from 53 to 79% and specificities of 82-91%. Relapse within 28 days was excluded almost entirely on the basis of WT1 expression combined with CD34(+) DC kinetics. Monitoring of WT1 expression and CD34(+) DC predict relapse of AML and MDS after RIC-HCT.

Authors: T. Lange, M. Hubmann, Ralph Burkhardt, G-N Franke, M. Cross, Markus Scholz, S. Leiblein, H. K. Al-Ali, J. Edelmann, Joachim Thiery, D. Niederwieser

Date Published: 1st Mar 2011

Publication Type: Journal article

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