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958 Publications visible to you, out of a total of 958
WHO grade-specific comparative genomic hybridization pattern of astrocytoma - a meta-analysis
Genetical Statistics and Systems Biology

Abstract (Expand)

To detect novel genetic alterations, many astrocytomas have been investigated by comparative genomic hybridization (CGH). To identify aberration profiles characteristic of World Health Organization … (WHO) grade I, II, III, and IV astrocytoma, we performed a meta-analysis of detailed genome wide CGH data of all 467 cases published so far. After expansion of all given aberrations to the maximum of 850 GTG-band resolution, the frequencies of genetic imbalances were calculated for each chromosomal band, separately for all four WHO grades. Low-grade astrocytoma has already demonstrated one characteristic of glioblastoma multiforme, gain of chromosome 7 with a hot spot at 7q32, but without loss of chromosome 10. In anaplastic astrocytoma, a more complex aberration pattern emerges from diffuse genetic imbalances. Gains of 7q32-q36 and 7p12 become the most frequent aberrations at chromosome 7. In glioblastoma multiforme, coarse aberrations like +7, -9p, -10, and -13 represent the most frequent aberrations as a characteristic pattern. In contrast to lower tumor grades, glioblastoma multiforme demonstrates +7p12 as the most frequently affected band on chromosome 7. To quantify the gradual transition from WHO grade II-IV astrocytoma, we calculated the relative increase and decrease in frequency for each detected aberration of the tumor genome. The most pronounced and diverse changes of genetic material occur at the virtual transition from low-grade to anaplastic astrocytoma. Further transition to glioblastoma multiforme is characterized by gain of 1p, chromosome 7, and loss of chromosome 10. Summing up, the expansion of the CGH results to the 850 GTG-band resolution enabled a meta-analysis to visualize WHO grade-specific aberration profiles in astrocytoma.

Authors: Heidrun Holland, Thomas Koschny, Peter Ahnert, Jürgen Meixensberger, Ronald Koschny

Date Published: 1st Oct 2010

Publication Type: Journal article

Genetic regulation of serum phytosterol levels and risk of coronary artery disease
Genetical Statistics and Systems Biology

Abstract (Expand)

BACKGROUND\backslashr\backslashnPhytosterols are plant-derived sterols that are taken up from food and can serve as biomarkers of cholesterol uptake. Serum levels are under tight genetic control. We … used a genomic approach to study the molecular regulation of serum phytosterol levels and potential links to coronary artery disease (CAD).\backslashr\backslashnMETHODS AND RESULTS\backslashr\backslashnA genome-wide association study for serum phytosterols (campesterol, sitosterol, brassicasterol) was conducted in a population-based sample from KORA (Cooperative Research in the Region of Augsburg) (n=1495) with subsequent replication in 2 additional samples (n=1157 and n=1760). Replicated single-nucleotide polymorphisms (SNPs) were tested for association with premature CAD in a metaanalysis of 11 different samples comprising 13 764 CAD cases and 13 630 healthy controls. Genetic variants in the ATP-binding hemitransporter ABCG8 and at the blood group ABO locus were significantly associated with serum phytosterols. Effects in ABCG8 were independently related to SNPs rs4245791 and rs41360247 (combined P=1.6 x 10(-50) and 6.2 x 10(-25), respectively; n=4412). Serum campesterol was elevated 12% for each rs4245791 T-allele. The same allele was associated with 40% decreased hepatic ABCG8 mRNA expression (P=0.009). Effects at the ABO locus were related to SNP rs657152 (combined P=9.4x10(-13)). Alleles of ABCG8 and ABO associated with elevated phytosterol levels displayed significant associations with increased CAD risk (rs4245791 odds ratio, 1.10; 95% CI, 1.06 to 1.14; P=2.2 x 10(-6); rs657152 odds ratio, 1.13; 95% CI, 1.07 to 1.19; P=9.4 x 10(-6)), whereas alleles at ABCG8 associated with reduced phytosterol levels were associated with reduced CAD risk (rs41360247 odds ratio, 0.84; 95% CI, 0.78 to 0.91; P=1.3 x 10(-5)).\backslashr\backslashnCONCLUSION\backslashr\backslashnCommon variants in ABCG8 and ABO are strongly associated with serum phytosterol levels and show concordant and previously unknown associations with CAD.

Authors: Daniel Teupser, Ronny Baber, Uta Ceglarek, Markus Scholz, Thomas Illig, Christian Gieger, Lesca Miriam Holdt, Alexander Leichtle, Karin H. Greiser, Dominik Huster, Patrick Linsel-Nitschke, Arne Schäfer, Peter S. Braund, Laurence Tiret, Klaus Stark, Dorette Raaz-Schrauder, Georg M. Fiedler, Wolfgang Wilfert, Frank Beutner, Stephan Gielen, Anika Grosshennig, Inke R. König, Peter Lichtner, Iris M. Heid, Alexander Kluttig, Nour E El Mokhtari, Diana Rubin, Arif B. Ekici, André Reis, Christoph D. Garlichs, Alistair S. Hall, Gert Matthes, Christian Wittekind, Christian Hengstenberg, Francois Cambien, Stefan Schreiber, Karl Werdan, Thomas Meitinger, Markus Loeffler, Nilesh J. Samani, Jeanette Erdmann, Heinz-Erich Wichmann, Heribert Schunkert, Joachim Thiery

Date Published: 1st Aug 2010

Publication Type: Journal article

Common variants associated with breast cancer in genome-wide association studies are modifiers of breast cancer risk in BRCA1 and BRCA2 mutation carriers
GC-HBOC - German Consortium for Hereditary Breast and Ovarian Cancer

Abstract (Expand)

Recent studies have identified single nucleotide polymorphisms (SNPs) that significantly modify breast cancer risk in BRCA1 and BRCA2 mutation carriers. Since these risk modifiers were originally … identified as genetic risk factors for breast cancer in genome-wide association studies (GWASs), additional risk modifiers for BRCA1 and BRCA2 may be identified from promising signals discovered in breast cancer GWAS. A total of 350 SNPs identified as candidate breast cancer risk factors (P \textless 1 x 10(-3)) in two breast cancer GWAS studies were genotyped in 3451 BRCA1 and 2006 BRCA2 mutation carriers from nine centers. Associations with breast cancer risk were assessed using Cox models weighted for penetrance. Eight SNPs in BRCA1 carriers and 12 SNPs in BRCA2 carriers, representing an enrichment over the number expected, were significantly associated with breast cancer risk (P(trend) \textless 0.01). The minor alleles of rs6138178 in SNRPB and rs6602595 in CAMK1D displayed the strongest associations in BRCA1 carriers (HR = 0.78, 95% CI: 0.69-0.90, P(trend) = 3.6 x 10(-4) and HR = 1.25, 95% CI: 1.10-1.41, P(trend) = 4.2 x 10(-4)), whereas rs9393597 in LOC134997 and rs12652447 in FBXL7 showed the strongest associations in BRCA2 carriers (HR = 1.55, 95% CI: 1.25-1.92, P(trend) = 6 x 10(-5) and HR = 1.37, 95% CI: 1.16-1.62, P(trend) = 1.7 x 10(-4)). The magnitude and direction of the associations were consistent with the original GWAS. In subsequent risk assessment studies, the loci appeared to interact multiplicatively for breast cancer risk in BRCA1 and BRCA2 carriers. Promising candidate SNPs from GWAS were identified as modifiers of breast cancer risk in BRCA1 and BRCA2 carriers. Upon further validation, these SNPs together with other genetic and environmental factors may improve breast cancer risk assessment in these populations.

Authors: Xianshu Wang, V. Shane Pankratz, Zachary Fredericksen, Robert Tarrell, Mary Karaus, Lesley McGuffog, Paul D. P. Pharaoh, Bruce A. J. Ponder, Alison M. Dunning, Susan Peock, Margaret Cook, Clare Oliver, Debra Frost, Olga M. Sinilnikova, Dominique Stoppa-Lyonnet, Sylvie Mazoyer, Claude Houdayer, Frans B. L. Hogervorst, Maartje J. Hooning, Marjolijn J. Ligtenberg, Amanda Spurdle, Georgia Chenevix-Trench, Rita K. Schmutzler, Barbara Wappenschmidt, Christoph Engel, Alfons Meindl, Susan M. Domchek, Katherine L. Nathanson, Timothy R. Rebbeck, Christian F. Singer, Daphne Gschwantler-Kaulich, Catherina Dressler, Anneliese Fink, Csilla I. Szabo, Michal Zikan, Lenka Foretova, Kathleen Claes, Gilles Thomas, Robert N. Hoover, David J. Hunter, Stephen J. Chanock, Douglas F. Easton, Antonis C. Antoniou, Fergus J. Couch

Date Published: 15th Jul 2010

Publication Type: Journal article

Human Diseases: hereditary breast ovarian cancer syndrome

Image-processing chain for a three-dimensional reconstruction of basal cell carcinomas.
ProstataCA

Abstract (Expand)

Basal cell carcinoma (BCC) is the most common malignant skin cancer. For a deeper insight into the specific growth patterns of the tumorous tissue in BCC, we have focused on the development of a novel … automated image-processing chain for 3D reconstruction of BCC using histopathological serial sections. For fully automatic delineation of the tumor within the tissue, we apply a fuzzy c-means segmentation method. We used a novel multi-grid form of the non-linear registration introduced by Braumann and Kuska in 2005 effectively suppressing registration runs into local minima (possibly caused by diffuse nature of the tumor). Our method was successfully applied in a proof-of-principle study for automated reconstruction.

Authors: P. Scheibe, U. D. Braumann, J. P. Kuska, M. Loffler, J. C. Simon, U. Paasch, T. Wetzig

Date Published: 1st Jul 2010

Publication Type: Not specified

Human Diseases: basal cell carcinoma

Transapical aortic valve implantation in 100 consecutive patients: comparison to propensity-matched conventional aortic valve replacement
Genetical Statistics and Systems Biology

Abstract (Expand)

AIMS\backslashr\backslashnTo evaluate the outcome of transapical aortic valve implantation (TA-AVI) in comparison to conventional surgery.\backslashr\backslashnMETHODS AND RESULTS\backslashr\backslashnOne … hundred consecutive high-risk patients with symptomatic aortic valve stenosis received TA-AVI using the Edwards SAPIEN pericardial xenograft between February 2006 and January 2008. Patient age was 82.7 +/- 5 years, 77 were females, logistic EuroSCORE predicted risk of mortality was 29.4 +/- 13% and Society Thoracic Surgeons score risk for mortality was 15.2 +/- 8.3%. Propensity score analysis was used to identify a control group of patients that underwent conventional aortic valve replacement (C-AVR). Transapical aortic valve implantation was performed successfully in 97 patients, whereas three patients required early conversion. There were no new onset neurological events in the TA-AVI group and early extubation was performed in 82 patients. Echocardiography revealed good valve function with low transvalvular gradients in all patients. Thirty-day survival was 90 +/- 3 vs. 85 +/- 4% for TA-AVI vs. C-AVR, and 1-year survival was 73 +/- 4 vs. 69 +/- 5% (P = 0.55).\backslashr\backslashnCONCLUSION\backslashr\backslashnTransapical aortic valve implantation is a safe, minimally invasive, and off-pump technique to treat high-risk patients with aortic stenosis. Results of the initial 100 patients are good and compare favourably to conventional surgery.

Authors: Thomas Walther, Gerhard Schuler, Michael Andrew Borger, Joerg Kempfert, Jörg Seeburger, Yvonne Rückert, Joerg Ender, Axel Linke, Markus Scholz, Volkmar Falk, Friedrich Wilhelm Mohr

Date Published: 1st Jun 2010

Publication Type: Journal article

A biomathematical model of human thrombopoiesis under chemotherapy.
HaematoOpt - Individualized model-based managing of the next-cycle thrombopenia of CHOEP/CHOP treated patients based on platelets dynamics during the previous cycles

Abstract (Expand)

Intensification of cytotoxic chemotherapy enhances the outcome of several malignancies but is limited by haematotoxicity. While neutropenia and anaemia can be treated with supportive growth factor … applications, thrombocytopenia remains a dose-limiting side effect due to the lack of clinically approved pharmaceutical growth factors. Hence, it is necessary to assess the degree of thrombocytopenia of newly designed intensified regimens in the planning phase of a clinical trial. We present a simple ordinary differential equations model of thrombopoiesis under chemotherapy which maps the dynamics of stem cells, CFU-Mk, megakaryocytes and platelets in spleen and circulation. Major regulatory cytokine of thrombopoiesis is thrombopoietin (TPO) whose production and consumption is explicitly modelled. TPO acts by increasing the number of mitoses of CFU-Mk and increasing the mass and maturation of megakaryocytes. Chemotherapy is modelled by a drug-dose and cell-stage specific acute cell loss. Most of the cell kinetic parameters of the model were taken from literature. Parameters regarding TPO regulation and chemotherapy toxicity were estimated by fitting the predictions of the model to time series data of platelets received from large clinical data sets of patients under seven different chemotherapies. We obtained a good agreement between model and data for all scenarios. Parameter estimates were biologically plausible throughout. For validation, the model also explains data of TPO and platelet dynamics after thrombopheresis taken from literature. We used the model to make clinically relevant predictions. Regarding thrombocytopenia we estimated that the CHOP regimen for the treatment of high-grade non-Hodgkin's lymphoma can be time-intensified to a cycle duration of 12 days while the time-intensified CHOEP regimen would result in severe cumulative toxicity. We conclude that our proposed model proved validity for both, different chemotherapeutic regimens and thrombopheresis as well. It is useful to assess the thrombocytopenic risk in the planning phase of a clinical trial.

Authors: M. Scholz, A. Gross, M. Loeffler

Date Published: 21st May 2010

Publication Type: Not specified

Standard International prognostic index remains a valid predictor of outcome for patients with aggressive CD20+ B-cell lymphoma in the rituximab era.
GLA - German Lymphoma Alliance

Abstract (Expand)

PURPOSE: The International Prognostic Index (IPI) is widely used for risk stratification of patients with aggressive B-cell lymphoma. The introduction of rituximab has markedly improved outcome, and … R-CHOP (rituximab + cyclophosphamide, doxorubicin, vincristine, prednisone) has become the standard treatment for CD20(+) diffuse large B-cell lymphoma. To investigate whether the IPI has maintained its power for risk stratification when rituximab is combined with CHOP, we analyzed the prognostic relevance of IPI in three prospective clinical trials. PATIENTS AND METHODS: In total, 1,062 patients treated with rituximab were included (MabThera International Trial [MInT], 380 patients; dose-escalated regimen of cyclophosphamide, doxorubicin, vincristine, etoposide, and prednisone (MegaCHOEP) trial, 72 patients; CHOP + rituximab for patients older than age 60 years [RICOVER-60] trial, 610 patients). A multivariate proportional hazards modeling was performed for single IPI factors under rituximab on event-free, progression-free, and overall survival. RESULTS: IPI score was significant for all three end points. Rituximab significantly improved treatment outcome within each IPI group resulting in a quenching of the Kaplan-Meier estimators. However, IPI was a significant prognostic factor in all three end points and the ordering of the IPI groups remained valid. The relative risk estimates of single IPI factors and their order in patients treated with R-CHOP were similar to those found with CHOP. CONCLUSION: The effects of rituximab were superimposed on the effects of CHOP with no interactions between chemotherapy and antibody therapy. These results demonstrate that the IPI is still valid in the R-CHOP era.

Authors: M. Ziepert, D. Hasenclever, E. Kuhnt, B. Glass, N. Schmitz, M. Pfreundschuh, M. Loeffler

Date Published: 10th May 2010

Publication Type: Not specified

Human Diseases: B-cell lymphoma

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