SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Kittner Steven J.) "

Sökning: WFRF:(Kittner Steven J.)

  • Resultat 1-10 av 23
  • [1]23Nästa
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Winkler, Thomas W., et al. (författare)
  • The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape A Large-Scale Genome-Wide Interaction Study
  • 2015
  • Ingår i: PLoS Genetics. - 1553-7390 .- 1553-7404. ; 11:10
  • Tidskriftsartikel (refereegranskat)abstract
    • Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially between men and women. To systematically screen for age-and/or sex-specific effects of genetic variants on BMI and WHRadjBMI, we performed meta-analyses of 114 studies (up to 320,485 individuals of European descent) with genome-wide chip and/or Metabochip data by the Genetic Investigation of Anthropometric Traits (GIANT) Consortium. Each study tested the association of up to similar to 2.8M SNPs with BMI and WHRadjBMI in four strata (men <= 50y, men > 50y, women <= 50y, women > 50y) and summary statistics were combined in stratum-specific meta-analyses. We then screened for variants that showed age-specific effects (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed significant (FDR< 5%) age-specific effects, of which 11 had larger effects in younger (< 50y) than in older adults (>= 50y). No sex-dependent effects were identified for BMI. For WHRadjBMI, we identified 44 loci (27 previously established for main effects, 17 novel) with sex-specific effects, of which 28 showed larger effects in women than in men, five showed larger effects in men than in women, and 11 showed opposite effects between sexes. No age-dependent effects were identified for WHRadjBMI. This is the first genome-wide interaction meta-analysis to report convincing evidence of age-dependent genetic effects on BMI. In addition, we confirm the sex-specificity of genetic effects on WHRadjBMI. These results may providefurther insights into the biology that underlies weight change with age or the sexually dimorphism of body shape.
2.
  •  
3.
  •  
4.
  •  
5.
  • Wu, Ona, et al. (författare)
  • Big Data Approaches to Phenotyping Acute Ischemic Stroke Using Automated Lesion Segmentation of Multi-Center Magnetic Resonance Imaging Data
  • 2019
  • Ingår i: Stroke. - American Heart Association. - 1524-4628. ; 50:7, s. 1734-1741
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and Purpose- We evaluated deep learning algorithms' segmentation of acute ischemic lesions on heterogeneous multi-center clinical diffusion-weighted magnetic resonance imaging (MRI) data sets and explored the potential role of this tool for phenotyping acute ischemic stroke. Methods- Ischemic stroke data sets from the MRI-GENIE (MRI-Genetics Interface Exploration) repository consisting of 12 international genetic research centers were retrospectively analyzed using an automated deep learning segmentation algorithm consisting of an ensemble of 3-dimensional convolutional neural networks. Three ensembles were trained using data from the following: (1) 267 patients from an independent single-center cohort, (2) 267 patients from MRI-GENIE, and (3) mixture of (1) and (2). The algorithms' performances were compared against manual outlines from a separate 383 patient subset from MRI-GENIE. Univariable and multivariable logistic regression with respect to demographics, stroke subtypes, and vascular risk factors were performed to identify phenotypes associated with large acute diffusion-weighted MRI volumes and greater stroke severity in 2770 MRI-GENIE patients. Stroke topography was investigated. Results- The ensemble consisting of a mixture of MRI-GENIE and single-center convolutional neural networks performed best. Subset analysis comparing automated and manual lesion volumes in 383 patients found excellent correlation (ρ=0.92; P<0.0001). Median (interquartile range) diffusion-weighted MRI lesion volumes from 2770 patients were 3.7 cm3 (0.9-16.6 cm3). Patients with small artery occlusion stroke subtype had smaller lesion volumes ( P<0.0001) and different topography compared with other stroke subtypes. Conclusions- Automated accurate clinical diffusion-weighted MRI lesion segmentation using deep learning algorithms trained with multi-center and diverse data is feasible. Both lesion volume and topography can provide insight into stroke subtypes with sufficient sample size from big heterogeneous multi-center clinical imaging phenotype data sets.
  •  
6.
  • Pfeiffer, Dorothea, et al. (författare)
  • Genetic Imbalance Is Associated With Functional Outcome After Ischemic Stroke
  • 2019
  • Ingår i: Stroke. - American Heart Association. - 1524-4628. ; 50:2, s. 298-304
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and Purpose- We sought to explore the effect of genetic imbalance on functional outcome after ischemic stroke (IS). Methods- Copy number variation was identified in high-density single-nucleotide polymorphism microarray data of IS patients from the CADISP (Cervical Artery Dissection and Ischemic Stroke Patients) and SiGN (Stroke Genetics Network)/GISCOME (Genetics of Ischaemic Stroke Functional Outcome) networks. Genetic imbalance, defined as total number of protein-coding genes affected by copy number variations in an individual, was compared between patients with favorable (modified Rankin Scale score of 0-2) and unfavorable (modified Rankin Scale score of ≥3) outcome after 3 months. Subgroup analyses were confined to patients with imbalance affecting ohnologs-a class of dose-sensitive genes, or to those with imbalance not affecting ohnologs. The association of imbalance with outcome was analyzed by logistic regression analysis, adjusted for age, sex, stroke subtype, stroke severity, and ancestry. Results- The study sample comprised 816 CADISP patients (age 44.2±10.3 years) and 2498 SiGN/GISCOME patients (age 67.7±14.2 years). Outcome was unfavorable in 122 CADISP and 889 SiGN/GISCOME patients. Multivariate logistic regression analysis revealed that increased genetic imbalance was associated with less favorable outcome in both samples (CADISP: P=0.0007; odds ratio=0.89; 95% CI, 0.82-0.95 and SiGN/GISCOME: P=0.0036; odds ratio=0.94; 95% CI, 0.91-0.98). The association was independent of age, sex, stroke severity on admission, stroke subtype, and ancestry. On subgroup analysis, imbalance affecting ohnologs was associated with outcome (CADISP: odds ratio=0.88; 95% CI, 0.80-0.95 and SiGN/GISCOME: odds ratio=0.93; 95% CI, 0.89-0.98) whereas imbalance without ohnologs lacked such an association. Conclusions- Increased genetic imbalance was associated with poorer functional outcome after IS in both study populations. Subgroup analysis revealed that this association was driven by presence of ohnologs in the respective copy number variations, suggesting a causal role of the deleterious effects of genetic imbalance.
  •  
7.
  • Rannikmaee, Kristiina, et al. (författare)
  • Common variation in COL4A1/COL4A2 is associated with sporadic cerebral small vessel disease
  • 2015
  • Ingår i: Neurology. - American Academy of Neurology. - 1526-632X. ; 84:9, s. 918-926
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives:We hypothesized that common variants in the collagen genes COL4A1/COL4A2 are associated with sporadic forms of cerebral small vessel disease.Methods:We conducted meta-analyses of existing genotype data among individuals of European ancestry to determine associations of 1,070 common single nucleotide polymorphisms (SNPs) in the COL4A1/COL4A2 genomic region with the following: intracerebral hemorrhage and its subtypes (deep, lobar) (1,545 cases, 1,485 controls); ischemic stroke and its subtypes (cardioembolic, large vessel disease, lacunar) (12,389 cases, 62,004 controls); and white matter hyperintensities (2,733 individuals with ischemic stroke and 9,361 from population-based cohorts with brain MRI data). We calculated a statistical significance threshold that accounted for multiple testing and linkage disequilibrium between SNPs (p < 0.000084).Results:Three intronic SNPs in COL4A2 were significantly associated with deep intracerebral hemorrhage (lead SNP odds ratio [OR] 1.29, 95% confidence interval [CI] 1.14-1.46, p = 0.00003; r(2) > 0.9 between SNPs). Although SNPs associated with deep intracerebral hemorrhage did not reach our significance threshold for association with lacunar ischemic stroke (lead SNP OR 1.10, 95% CI 1.03-1.18, p = 0.0073), and with white matter hyperintensity volume in symptomatic ischemic stroke patients (lead SNP OR 1.07, 95% CI 1.01-1.13, p = 0.016), the direction of association was the same. There was no convincing evidence of association with white matter hyperintensities in population-based studies or with non-small vessel disease cerebrovascular phenotypes.Conclusions:Our results indicate an association between common variation in the COL4A2 gene and symptomatic small vessel disease, particularly deep intracerebral hemorrhage. These findings merit replication studies, including in ethnic groups of non-European ancestry.
  •  
8.
  • Schirmer, Markus D., et al. (författare)
  • Brain Volume : An Important Determinant of Functional Outcome After Acute Ischemic Stroke
  • 2020
  • Ingår i: Mayo Clinic Proceedings. - Mayo Clinic Proceedings. - 0025-6196. ; 95:5, s. 955-965
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: To determine whether brain volume is associated with functional outcome after acute ischemic stroke (AIS). Patients and Methods: This study was conducted between July 1, 2014, and March 16, 2019. We analyzed cross-sectional data of the multisite, international hospital-based MRI-Genetics Interface Exploration study with clinical brain magnetic resonance imaging obtained on admission for index stroke and functional outcome assessment. Poststroke outcome was determined using the modified Rankin Scale score (0-6; 0 = asymptomatic; 6 = death) recorded between 60 and 190 days after stroke. Demographic characteristics and other clinical variables including acute stroke severity (measured as National Institutes of Health Stroke Scale score), vascular risk factors, and etiologic stroke subtypes (Causative Classification of Stroke system) were recorded during index admission. Results: Utilizing the data from 912 patients with AIS (mean ± SD age, 65.3±14.5 years; male, 532 [58.3%]; history of smoking, 519 [56.9%]; hypertension, 595 [65.2%]) in a generalized linear model, brain volume (per 155.1 cm3) was associated with age (β −0.3 [per 14.4 years]), male sex (β 1.0), and prior stroke (β −0.2). In the multivariable outcome model, brain volume was an independent predictor of modified Rankin Scale score (β −0.233), with reduced odds of worse long-term functional outcomes (odds ratio, 0.8; 95% CI, 0.7-0.9) in those with larger brain volumes. Conclusion: Larger brain volume quantified on clinical magnetic resonance imaging of patients with AIS at the time of stroke purports a protective mechanism. The role of brain volume as a prognostic, protective biomarker has the potential to forge new areas of research and advance current knowledge of the mechanisms of poststroke recovery.
  •  
9.
  • Schirmer, Markus D., et al. (författare)
  • White matter hyperintensity quantification in large-scale clinical acute ischemic stroke cohorts – The MRI-GENIE study
  • 2019
  • Ingår i: NeuroImage: Clinical. - Elsevier. - 2213-1582. ; 23
  • Tidskriftsartikel (refereegranskat)abstract
    • White matter hyperintensity (WMH) burden is a critically important cerebrovascular phenotype linked to prediction of diagnosis and prognosis of diseases, such as acute ischemic stroke (AIS). However, current approaches to its quantification on clinical MRI often rely on time intensive manual delineation of the disease on T2 fluid attenuated inverse recovery (FLAIR), which hinders high-throughput analyses such as genetic discovery. In this work, we present a fully automated pipeline for quantification of WMH in clinical large-scale studies of AIS. The pipeline incorporates automated brain extraction, intensity normalization and WMH segmentation using spatial priors. We first propose a brain extraction algorithm based on a fully convolutional deep learning architecture, specifically designed for clinical FLAIR images. We demonstrate that our method for brain extraction outperforms two commonly used and publicly available methods on clinical quality images in a set of 144 subject scans across 12 acquisition centers, based on dice coefficient (median 0.95; inter-quartile range 0.94–0.95; p < 0.01) and Pearson correlation of total brain volume (r = 0.90). Subsequently, we apply it to the large-scale clinical multi-site MRI-GENIE study (N = 2783) and identify a decrease in total brain volume of −2.4 cc/year. Additionally, we show that the resulting total brain volumes can successfully be used for quality control of image preprocessing. Finally, we obtain WMH volumes by building on an existing automatic WMH segmentation algorithm that delineates and distinguishes between different cerebrovascular pathologies. The learning method mimics expert knowledge of the spatial distribution of the WMH burden using a convolutional auto-encoder. This enables successful computation of WMH volumes of 2533 clinical AIS patients. We utilize these results to demonstrate the increase of WMH burden with age (0.950 cc/year) and show that single site estimates can be biased by the number of subjects recruited.
  •  
10.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 23
  • [1]23Nästa
Åtkomst
fritt online (5)
Typ av publikation
tidskriftsartikel (22)
konferensbidrag (1)
Typ av innehåll
refereegranskat (22)
övrigt vetenskapligt (3)
Författare/redaktör
Kittner, Steven J. (20)
Rosand, Jonathan (17)
Lindgren, Arne, (16)
Sharma, Pankaj, (15)
Slowik, Agnieszka (14)
Mitchell, Braxton D. (14)
visa fler...
Worrall, Bradford B. (13)
Meschia, James F. (13)
Dichgans, Martin (13)
Thijs, Vincent (13)
Woo, Daniel (12)
Lemmens, Robin (12)
Markus, Hugh S (12)
Rothwell, Peter M. (11)
Jimenez-Conde, Jordi (11)
Schmidt, Reinhold, (10)
Cole, John W (10)
Rundek, Tatjana, (9)
Jern, Christina (9)
Malik, Rainer (9)
Sacco, Ralph L., (8)
Sudlow, Cathie (8)
McArdle, Patrick F (8)
Bevan, Steve (8)
Traylor, Matthew (8)
Tatlisumak, Turgut, (7)
Seshadri, Sudha, (7)
Bis, Joshua C., (7)
Fornage, Myriam, (7)
Rost, Natalia S. (7)
de Bakker, Paul I W (7)
Holliday, Elizabeth ... (7)
Debette, Stephanie, (6)
Norrving, Bo, (6)
Roquer, Jaume (6)
Saleheen, Danish, (5)
Thorleifsson, Gudmar (5)
Jood, Katarina, (5)
Anderson, Christophe ... (5)
Ay, Hakan (5)
Grewal, Raji P (5)
Lee, Jin-Moo (5)
Cheng, Yu-Ching (5)
Ikram, M. Arfan, (4)
Langefeld, Carl D. (4)
Montaner, Joan (4)
Falcone, Guido J., (4)
Hopewell, Jemma C. (4)
Maguire, Jane (4)
Gretarsdottir, Solve ... (4)
visa färre...
Lärosäte
Lunds universitet (19)
Göteborgs universitet (12)
Uppsala universitet (5)
Karolinska Institutet (2)
Umeå universitet (1)
Språk
Engelska (23)
Forskningsämne (UKÄ/SCB)
Medicin och hälsovetenskap (23)
Teknik (1)

År

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy