101
|
Isola AA, Ziegler A, Koehler T, Niessen WJ, Grass M. Motion-compensated iterative cone-beam CT image reconstruction with adapted blobs as basis functions. Phys Med Biol 2008; 53:6777-97. [PMID: 18997267 DOI: 10.1088/0031-9155/53/23/009] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This paper presents a three-dimensional method to reconstruct moving objects from cone-beam X-ray projections using an iterative reconstruction algorithm and a given motion vector field. For the image representation, adapted blobs are used, which can be implemented efficiently as basis functions. Iterative reconstruction requires the calculation of line integrals (forward projections) through the image volume, which are compared with the actual measurements to update the image volume. In the existence of a divergent motion vector field, a change in the volumes of the blobs has to be taken into account in the forward and backprojections. An efficient method to calculate the line integral through the adapted blobs is proposed. It solves the problem, how to compensate for the divergence in the motion vector field on a grid of basis functions. The method is evaluated on two phantoms, which are subject to three different known motions. Moreover, a motion-compensated filtered back-projection reconstruction method is used, and the reconstructed images are compared. Using the correct motion vector field with the iterative motion-compensated reconstruction, sharp images are obtained, with a quality that is significantly better than gated reconstructions.
Collapse
|
102
|
Noack B, Görgens H, Hempel U, Fanghänel J, Hoffmann T, Ziegler A, Schackert H. Cathepsin C Gene Variants in Aggressive Periodontitis. J Dent Res 2008; 87:958-63. [DOI: 10.1177/154405910808701017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Cathepsin C ( CTSC) mutations are known to cause Papillon-Lefèvre syndrome. The aim of this study was to examine the association of CTSC genotype with susceptibility to non-syndromic aggressive periodontitis. The CTSC gene was analyzed in 110 persons with generalized aggressive periodontitis in comparison with 78 control individuals, after identifying different variants in a cohort of 100 persons. Five out of 19 discovered variants were included in this association study, representing 5 single-nucleotide polymorphism groups in tight linkage disequilibrium. The relevance of genotypes on enzyme function was examined. The carrier frequency of the missense variant p.I453V was significantly increased in persons with disease compared with healthy control individuals (17.3% vs. 6.4%, p < 0.05). CTSC activity in leukocytes from individuals harboring this variant was significantly reduced (119.8 ΔOD/min*105 cells, 95% confidence interval 17.4–174.9, p = 0.018). No influence of promoter variants was found on mRNA expression. The results support the hypothesis that CTSC gene variants contribute to increased susceptibility in generalized aggressive periodontitis.
Collapse
|
103
|
Hilgendorff A, Heidinger K, Pfeiffer A, Bohnert A, König IR, Ziegler A, Merz C, Frey G, Chakraborty T, Gortner L, Bein G. Erratum: Association of polymorphisms in the mannose-binding lectin gene and pulmonary morbidity in preterm infants. Genes Immun 2008. [DOI: 10.1038/gene.2008.46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
104
|
Ziegler A, Baltzer J. Wehenhemmende Medikamente. Geburtshilfe Frauenheilkd 2008. [DOI: 10.1055/s-2007-1023154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
|
105
|
König I, Malley J, Pajevic S, Weimar C, Diener HC, Ziegler A. Patient-centered yes/no prognosis using learning machines. INT J DATA MIN BIOIN 2008; 2:289-341. [PMID: 19216340 PMCID: PMC2754835 DOI: 10.1504/ijdmb.2008.022149] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the last 15 years several machine learning approaches have been developed for classification and regression. In an intuitive manner we introduce the main ideas of classification and regression trees, support vector machines, bagging, boosting and random forests. We discuss differences in the use of machine learning in the biomedical community and the computer sciences. We propose methods for comparing machines on a sound statistical basis. Data from the German Stroke Study Collaboration is used for illustration. We compare the results from learning machines to those obtained by a published logistic regression and discuss similarities and differences.
Collapse
|
106
|
Roth R, Schiretz V, Hummel M, Ziegler A. Psychologische Aspekte in der BABYDIAB Studie: 11 Jahresuntersuchung. DIABETOL STOFFWECHS 2008. [DOI: 10.1055/s-2008-1076173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
107
|
Lohmann-Hedrich K, Neumann A, Kleensang A, Lohnau T, Muhle H, Djarmati A, Konig IR, Pramstaller PP, Schwinger E, Kramer PL, Ziegler A, Stephani U, Klein C. Evidence for linkage of restless legs syndrome to chromosome 9p: Are there two distinct loci? Neurology 2007; 70:686-94. [DOI: 10.1212/01.wnl.0000282760.07650.ba] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
108
|
Hilgendorff A, Heidinger K, Pfeiffer A, Bohnert A, König IR, Ziegler A, Merz C, Frey G, Chakraborty T, Gortner L, Bein G. Association of polymorphisms in the mannose-binding lectin gene and pulmonary morbidity in preterm infants. Genes Immun 2007; 8:671-7. [PMID: 17898783 DOI: 10.1038/sj.gene.6364432] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Deficiency in the collectin mannose-binding lectin (MBL) increases the risk for pulmonary and systemic infections and its complications in children and adults. The aim of this prospective cohort study was to determine the genetic association of sequence variations within the MBL gene with systemic infections and pulmonary short- and long-term complications in preterm infants below 32 weeks gestational age (GA). Three single-nucleotide polymorphisms (SNPs) in the coding region and one SNP in the promotor region of MBL2 were genotyped by direct sequencing and with sequence-specific probes in 284 newborn infants <32 weeks GA. Clinical variables were comprehensively monitored. An association was found between two SNPs and the development of bronchopulmonary dysplasia (BPD), defined as persistent oxygen requirement at 36 weeks postmenstrual age, adjusting for covariates GA, grade of respiratory distress syndrome and days on mechanical ventilation (rs1800450 (exon 1 at codon 54, B variant): odds ratio dominant model (OR)=3.59, 95% confidence interval (CI)=1.62-7.98; rs7096206 (-221, X variant): OR=2.40, 95% CI=1.16-4.96). Haplotype analyses confirmed the association to BPD, and a single haplotype (frequency 56%) including all SNPs in their wild-type form showed a negative association with the development of BPD. We detected no association between the MBL gene variations and the development of early-onset infections or further pulmonary complications. Frequent variants of the MBL gene, leading to low MBL concentrations, are associated with the diagnosis of BPD in preterm infants. This provides a basis for potential therapeutic options and further genetic and proteomic analysis of the function of MBL in the resistance against pulmonary long-term complications in preterm infants.
Collapse
|
109
|
Grouven U, Bender R, Ziegler A, Lange S. [Comparing methods of measurement]. Dtsch Med Wochenschr 2007; 132 Suppl 1:e69-73. [PMID: 17530604 DOI: 10.1055/s-2007-959047] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
110
|
|
111
|
|
112
|
|
113
|
Ziegler A, Lange S, Bender R. [Survival analysis: Cox regression]. Dtsch Med Wochenschr 2007; 132 Suppl 1:e42-4. [PMID: 17530596 DOI: 10.1055/s-2007-959039] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
114
|
|
115
|
Ziegler A, Lange S, Bender R. [Systematic reviews and meta-analyses]. Dtsch Med Wochenschr 2007; 132 Suppl 1:e48-52. [PMID: 17530598 DOI: 10.1055/s-2007-959042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
116
|
Füchtenbusch M, Hummel M, Knopff A, Wentzel A, Bonifacio E, Ziegler A. APGAR scores are lower in offspring from mothers with type 1 diabetes – results from the BABY DIAB study. DIABETOL STOFFWECHS 2007. [DOI: 10.1055/s-2007-984748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
117
|
|
118
|
Gautschi O, Huegli B, Ziegler A, Gugger M, Heighway J, Ratschiller D, Mack PC, Gumerlock PH, Kung HJ, Stahel RA, Gandara DR, Betticher DC. Origin and prognostic value of circulating KRAS mutations in lung cancer patients. Cancer Lett 2007; 254:265-73. [PMID: 17449174 DOI: 10.1016/j.canlet.2007.03.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2007] [Revised: 03/09/2007] [Accepted: 03/12/2007] [Indexed: 10/23/2022]
Abstract
Because of the current controversy on the origin and clinical value of circulating KRAS codon 12 mutations in lung cancer, we screened 180 patients using a combined restriction fragment-length polymorphism and polymerase chain reaction (RFLP-PCR) assay. We detected KRAS mutations in 9% plasma samples and 0% matched lymphocytes. Plasma KRAS mutations correlated significantly with poor prognosis. We validated the positive results in a second laboratory by DNA sequencing and found matching codon 12 sequences in blood and tumor in 78% evaluable cases. These results support the notion that circulating KRAS mutations originate from tumors and are prognostically relevant in lung cancer.
Collapse
|
119
|
Berriel Diaz M, Krones-Herzig A, Ziegler A, Metzger D, Herzig S. Control of hepatic and systemic lipid metabolism through the nuclear receptor co-factor RIP140. Exp Clin Endocrinol Diabetes 2007. [DOI: 10.1055/s-2007-972233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
120
|
Chichelnitskiy E, Vegiopoulos A, Ziegler A, Hardeland U, Lemke U, Herzig S. Cross talk between hormonal and pro-inflammatory pathways in the control of hepatic glucose metabolism. Exp Clin Endocrinol Diabetes 2007. [DOI: 10.1055/s-2007-972223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
121
|
Schulte-Körne G, Ziegler A, Deimel W, Schumacher J, Plume E, Bachmann C, Kleensang A, Propping P, Nöthen MM, Warnke A, Remschmidt H, König IR. Interrelationship and Familiality of Dyslexia Related Quantitative Measures. Ann Hum Genet 2007; 71:160-75. [PMID: 17038000 DOI: 10.1111/j.1469-1809.2006.00312.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dyslexia is a complex gene-environment disorder with poorly understood etiology that affects about 5% of school-age children. Dyslexia occurs in all languages and is associated with a high level of social and psychological morbidity for the individual and their family; approximately 40-50% have persistent disability into adulthood. The core symptoms are word reading and spelling deficits, but several other cognitive components influence the core phenotype. A broad spectrum of dyslexia related phenotypes, including phonological decoding, phoneme awareness, orthographic processing, short-term memory, rapid naming and basic mathematical abilities, were investigated in large sample of 287 German dyslexia families. We explored the interrelationship between the component phenotypes using correlation and principal component analyses (PCA). In addition, we estimated familiality for phenotypes as well as for the factors suggested by PCA. The correlation between the component phenotypes varied between -0.1 and 0.7. The PCA resulted in three factors: a general dyslexia factor, a speed of processing factor and a mathematical abilities factor. The familiality estimates of single components and factors ranged between 0.25 and 0.63. Instead of analyzing single dyslexia-related components, multivariate analyses including factor analytic approaches may help in the identification of susceptibility genes.
Collapse
|
122
|
Ziegler A, Köhler T, Proksa R. Noise and resolution in images reconstructed with FBP and OSC algorithms for CT. Med Phys 2007; 34:585-98. [PMID: 17388176 DOI: 10.1118/1.2409481] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
This paper presents a comparison between an analytical and a statistical iterative reconstruction algorithm for computed transmission tomography concerning their noise and resolution performance. The reconstruction of two-dimensional images from simulated fan-beam transmission data is performed with a filtered back-projection (FBP) type reconstruction and an iterative ordered subsets convex (OSC) maximum-likelihood method. A special software phantom, which allows measuring the resolution and noise in a nonambiguous way, is used to simulate transmission tomography scans with different signal-to-noise ratios (SNR). The noise and modulation transfer function is calculated for FBP and OSC reconstruction at several positions, distributed over the field-of-view (FOV). The reconstruction with OSC using different numbers of subsets shows an inverse linear relation to the number of iterations that are necessary to reach a certain resolution and SNR, i.e., increasing the number of subsets by a factor x reduces the number of required iterations by the same factor. The OSC algorithm is able to achieve a nearly homogeneous high resolution over the whole FOV, which is not achieved with FBP. The OSC method achieves a lower level of noise compared with FBP at the same resolution. The reconstruction with OSC can save a factor of up to nine of x-ray dose compared with FBP in the investigated range of noise levels.
Collapse
|
123
|
|
124
|
Ziegler A, Lange S, Bender R. Überlebenszeitanalyse: Eigenschaften und Kaplan-Meier Methode. Dtsch Med Wochenschr 2007; 132 Suppl 1:e36-8. [PMID: 17530594 DOI: 10.1055/s-2007-959038] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
125
|
Lohmann K, Ziegler A, Muhle H, Neumann A, Kleensang A, Lohnau T, König IR, Stephani U, Klein C. Ein zweiter Genort für das Restless-Legs-Syndrom auf Chromosom 9p? AKTUELLE NEUROLOGIE 2007. [DOI: 10.1055/s-2007-987784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|