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1005 Publications visible to you, out of a total of 1005
Comparison of estimators for measures of linkage disequilibrium
Genetical Statistics and Systems Biology

Abstract (Expand)

The measurement of biallelic pair-wise association called linkage disequilibrium (LD) is an important issue in order to understand the genomic architecture. A plethora of measures of association in two … by two tables have been proposed in the literature. Beside the problem of choosing an appropriate measure, the problem of their estimation has been neglected in the literature. It needs to be emphasized that the definition of a measure and the choice of an estimator function for it are conceptually unrelated tasks. In this paper, we compare the performance of various estimators for the three popular LD measures D’, r and Y in a simulation study for small to moderate samples sizes (N\textless=500). The usual frequency-plug-in estimators can lead to unreliable or undefined estimates. Estimators based on the computationally expensive volume measures have been proposed recently as a remedy to this well-known problem. We confirm that volume estimators have better expected mean square error than the naive plug-in estimators. But they are outperformed by estimators plugging-in easy to calculate non-informative Bayesian probability estimates into the theoretical formulae for the measures. Fully Bayesian estimators with non-informative Dirichlet priors have comparable accuracy but are computationally more expensive. We recommend the use of non-informative Bayesian plug-in estimators based on Jeffreys’ prior, in particular when dealing with SNP array data where the occurrence of small table entries and table margins is likely.

Authors: Markus Scholz, Dirk Hasenclever

Date Published: 2010

Publication Type: Journal article

Designing a Concept for an IT-Infrastructure for an Integrated Research and Treatment Center
Management of health information systems

Abstract (Expand)

Healthcare and medical research in Germany are heading to more interconnected systems. New initiatives are funded by the German government to encourage the development of Integrated Research and Treatment … Centers (IFB). Within an IFB new organizational structures and infrastructures for interdisciplinary, translational and trans-sectoral working relationship between existing rigid separated sectors are intended and needed. This paper describes how an IT-infrastructure of an IFB could look like, what major challenges have to be solved and what methods can be used to plan such a complex IT-infrastructure in the field of healthcare. By means of project management, system analyses, process models, 3LGM\textlesssup\textgreater2\textless/sup\textgreater-models and resource plans an appropriate concept with different views is created. This concept supports the information management in its enterprise architecture planning activities and implies a first step of implementing a connected healthcare and medical research platform.

Authors: Sebastian Stäubert, Alfred Winter, R. Speer, M. Loffler

Date Published: 2010

Publication Type: InCollection

Das IHE XDS Integration Profile besser verstehen und umsetzen durch Darstellung als 3LGM^2-Modell
Management of health information systems

Abstract

Not specified

Authors: F. Stephan, R. Hussein, Alfred Winter, Franziska Jahn, Sebastian Stäubert, Alexander Strübing

Date Published: 2010

Publication Type: InCollection

3LGM^2 V3 – Das überarbeitete und erweiterte Drei-Ebenen-Metamodell
Management of health information systems

Abstract

Not specified

Authors: Franziska Jahn, Alfred Winter, A. Strübing, L. Ißler, T. Wendt

Date Published: 2010

Publication Type: InCollection

Das Drei-Ebenen-Metamodell für die Modellierung und Beschreibung von Informationssystemen (3LGM^2 V3)
Management of health information systems

Abstract

Not specified

Authors: Alfred Winter, L. Ißler, Franziska Jahn, A. Strübing, T. Wendt

Date Published: 2010

Publication Type: Misc

Contralateral breast cancer risk in BRCA1 and BRCA2 mutation carriers
GC-HBOC - German Consortium for Hereditary Breast and Ovarian Cancer

Abstract (Expand)

PURPOSE To estimate the risk for contralateral breast cancer in members of BRCA1- and BRCA2-positive families and to determine predictive risk factors. PATIENTS AND METHODS A retrospective, multicenter, …er, cohort study was performed from 1996 until 2008 and comprised 2,020 women with unilateral breast cancer (index patients, n = 978; relatives, n = 1.42) from 978 families who had a BRCA1 or BRCA2 mutation. Cox regression analysis was applied to assess the association of age at first breast cancer with time from first to contralateral breast cancer, stratified by the affected BRCA gene. RESULTS The cumulative risk for contralateral breast cancer 25 years after first breast cancer was 47.4% (95% CI, 38.8% to 56.0%) for patients from families with BRCA1 or BRCA2 mutations. Members of families with BRCA1 mutations had a 1.6-fold (95% CI, 1.2-fold to 2.3-fold) higher risk of contralateral breast cancer than members of families with BRCA2 mutations. Younger age at first breast cancer was associated with a significantly higher risk of contralateral breast cancer in patients with BRCA1 mutation, and a trend was observed in patients with BRCA2 mutation. After 25 years, 62.9% (95% CI, 50.4% to 75.4%) of patients with BRCA1 mutation who were younger than 40 years of age at first breast cancer developed contralateral breast cancer, compared with only 19.6% (95% CI, 5.3% to 33.9%) of those who were older than 50 years of age at first breast cancer. CONCLUSION Contralateral breast cancer risk depends on age at first breast cancer and on the affected BRCA gene, and this risk should be considered in treatment planning.

Authors: Monika K. Graeser, Christoph Engel, Kerstin Rhiem, Dorothea Gadzicki, Ulrich Bick, Karin Kast, Ursula G. Froster, Bettina Schlehe, Astrid Bechtold, Norbert Arnold, Sabine Preisler-Adams, Carolin Nestle-Kraemling, Mohammad Zaino, Markus Loeffler, Marion Kiechle, Alfons Meindl, Dominic Varga, Rita K. Schmutzler

Date Published: 10th Dec 2009

Publication Type: Journal article

Human Diseases: hereditary breast ovarian cancer syndrome

Molecular predictors of progression-free and overall survival in patients with newly diagnosed glioblastoma: a prospective translational study of the German Glioma Network.
GGN - German Glioma Network

Abstract (Expand)

PURPOSE: The prognostic value of genetic alterations characteristic of glioblastoma in patients treated according to present standards of care is unclear. PATIENTS AND METHODS: Three hundred one patients … with glioblastoma were prospectively recruited between October 2004 and December 2006 at the clinical centers of the German Glioma Network. Two hundred fifty-eight patients had radiotherapy, 199 patients had temozolomide, 189 had both, and seven had another chemotherapy as the initial treatment. The tumors were investigated for TP53 mutation, p53 immunoreactivity, epidermal growth factor receptor, cyclin-dependent kinase CDK 4 or murine double minute 2 amplification, CDKN2A homozygous deletion, allelic losses on chromosome arms 1p, 9p, 10q, and 19q, O(6)-methylguanine methyltransferase (MGMT) promoter methylation, and isocitrate dehydrogenase 1 (IDH1) mutations. RESULTS: Median progression-free (PFS) and overall survival (OS) were 6.8 and 12.5 months. Multivariate analysis revealed younger age, higher performance score, MGMT promoter methylation, and temozolomide radiochemotherapy as independent factors associated with longer OS. MGMT promoter methylation was associated with longer PFS (relative risk [RR], 0.5; 95% CI, 0.38 to 0.68; P < .001) and OS (RR, 0.39; 95% CI, 0.28 to 0.54; P < .001) in patients receiving temozolomide. IDH1 mutations were associated with prolonged PFS (RR, 0.42; 95% CI, 0.19 to 0.91; P = .028) and a trend for prolonged OS (RR, 0.43; 95% CI, 0.15 to 1.19; P = .10). No other molecular factor was associated with outcome. CONCLUSION: Molecular changes associated with gliomagenesis do not predict response to therapy in glioblastoma patients managed according to current standards of care. MGMT promoter methylation and IDH1 mutational status allow for stratification into prognostically distinct subgroups.

Authors: M. Weller, J. Felsberg, C. Hartmann, H. Berger, J. P. Steinbach, J. Schramm, M. Westphal, G. Schackert, M. Simon, J. C. Tonn, O. Heese, D. Krex, G. Nikkhah, T. Pietsch, O. Wiestler, G. Reifenberger, A. von Deimling, M. Loeffler

Date Published: 1st Dec 2009

Publication Type: Not specified

Human Diseases: brain glioma, glioblastoma multiforme

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