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Quantitative susceptibility mapping

J M G van Bergen, X Li, J Hua, S J Schreiner, S C Steininger, F C Quevenco, M Wyss, A F Gietl, V Treyer, S E Leh, F Buck, R M Nitsch, K P Pruessmann, P C M van Zijl, C Hock, P G Unschuld
Quantitative Susceptibility Mapping (QSM) MRI at 7 Tesla and 11-Carbon Pittsburgh-Compound-B PET were used for investigating the relationship between brain iron and Amyloid beta (Aβ) plaque-load in a context of increased risk for Alzheimer's disease (AD), as reflected by the Apolipoprotein E ε4 (APOE-e4) allele and mild cognitive impairment (MCI) in elderly subjects. Carriers of APOE-e4 with normal cognition had higher cortical Aβ-plaque-load than non-carriers. In MCI an association between APOE-e4 and higher Aβ-plaque-load was observable both for cortical and subcortical brain-regions...
October 17, 2016: Scientific Reports
Angelica Giancaspro, Stefania L Giove, Daniela Zito, A Blanco, Agata Gadaleta
Fusarium head blight (scab) is one of the most widespread and damaging diseases of wheat, causing grain yield and quality losses and production of harmful mycotoxins. Development of resistant varieties is hampered by lack of effective resistance sources in the tetraploid wheat primary gene pool. Here we dissected the genetic basis of resistance in a new durum wheat (Triticum turgidum ssp. durum) Recombinant inbred lines (RILs) population obtained by crossing an hexaploid resistant line and a durum susceptible cultivar...
2016: Frontiers in Plant Science
Wanqing Liu, Quentin M Anstee, Xiaoliang Wang, Samer Gawrieh, Eric R Gamazon, Shaminie Athinarayanan, Yang-Lin Liu, Rebecca Darlay, Heather J Cordell, Ann K Daly, Chris P Day, Naga Chalasani
The increased expression of PNPLA3(148M) leads to hepatosteatosis in mice. This study aims to investigate the genetic control of hepatic PNPLA3 transcription and to explore its impact on NAFLD risk in humans. Through a locus-wide expression quantitative trait loci (eQTL) mapping in two human liver sample sets, a PNPLA3 intronic SNP, rs139051 A>G was identified as a significant eQTL (p = 6.6×10(-8)) influencing PNPLA3 transcription, with the A allele significantly associated with increased PNPLA3 mRNA. An electrophoresis mobility shift assay further demonstrated that the A allele has enhanced affinity to nuclear proteins than the G allele...
October 13, 2016: Aging
Congbo Cai, Xi Chen, Weijun Liu, Shuhui Cai, Delu Zeng, Xinghao Ding
Quantitative susceptibility mapping (QSM) reconstruction is a well-known ill-posed problem. Various regularization techniques have been proposed for solving this problem. In this paper, a rapid method is proposed that uses ℓ0 norm minimization in a gradient domain. Because ℓ0 minimization is an NP-hard problem, a special alternating optimization strategy is employed to simplify the reconstruction algorithm. The proposed algorithm uses only simple point-wise multiplications and thresholding operations, and significantly speeds up the calculation...
October 4, 2016: Computers in Biology and Medicine
Dinh Minh Tran, André Clément-Demange, Marine Déon, Dominique Garcia, Vincent Le Guen, Anne Clément-Vidal, Mouman Soumahoro, Aurélien Masson, Philippe Label, Mau Tuy Le, Valérie Pujade-Renaud
An indirect phenotyping method was developed in order to estimate the susceptibility of rubber tree clonal varieties to Corynespora Leaf Fall (CLF) disease caused by the ascomycete Corynespora cassiicola. This method consists in quantifying the impact of fungal exudates on detached leaves by measuring the induced electrolyte leakage (EL%). The tested exudates were either crude culture filtrates from diverse C. cassiicola isolates or the purified cassiicolin (Cas1), a small secreted effector protein produced by the aggressive isolate CCP...
2016: PloS One
Ferdinand Schweser, Simon Daniel Robinson, Ludovic de Rochefort, Wei Li, Kristian Bredies
The elimination of so-called background fields is an essential step in phase MRI and quantitative susceptibility mapping (QSM). Background fields, which are caused by sources outside the region of interest (ROI), are often one to two orders of magnitude stronger than tissue-related field variations from within the ROI, hampering quantitative interpretation of field maps. This paper reviews the current literature on background elimination algorithms for QSM and provides insights into similarities and differences between the many algorithms proposed...
October 7, 2016: NMR in Biomedicine
Pedro Correa Brauner, Albrecht E Melchinger, Tobias A Schrag, H Friedrich Utz, Wolfgang Schipprack, Bettina Kessel, Milena Ouzunova, Thomas Miedaner
Six quantitative trait loci (QTL) for Gibberella ear rot resistance in maize were tested in two different genetic backgrounds; three QTL displayed an effect in few near isogenic line pairs. Few quantitative trait loci (QTL) mapping studies for Gibberella ear rot (GER) have been conducted, but no QTL have been verified so far. QTL validation is prudent before their implementation into marker-assisted selection (MAS) programs. Our objectives were to (1) validate six QTL for GER resistance, (2) evaluate the QTL across two genetic backgrounds, (3) investigate the genetic background outside the targeted introgressions...
October 5, 2016: TAG. Theoretical and Applied Genetics. Theoretische und Angewandte Genetik
Yuki Shinohara, Ayumi Kato, Eijiro Yamashita, Toshihide Ogawa
BACKGROUND: To evaluate the detectability of arterial acute thrombus on R2* map by iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) IQ compared with T2*-weighted imaging (T2*WI). METHODS: Twenty-six patients with acute cerebral infarction who underwent R2* map and T2*WI were reviewed. We performed visual assessment of each sequence regarding the visibility of susceptibility effect reflecting acute thrombus and quantitative evaluation of the thrombus on R2* map...
September 2016: Yonago Acta Medica
Dong Zhou, Junghun Cho, Jingwei Zhang, Pascal Spincemaille, Yi Wang
PURPOSE: We assessed the accuracy of quantitative susceptibility mapping in a gadolinium balloon phantom with a large range of susceptibility values and imaging resolutions at 1.5 and 3 Tesla (T). THEORY AND METHODS: The phantom contained sources with susceptibility values of 0.4, 0.8, 1.6, and 3.2 ppm and was imaged at isotropic resolutions of 0.7, 0.8, 1.2, and 1.8 mm. Numerical simulations were performed to match the experimental findings. Voxel sensitivity effects were used to explain the susceptibility underestimations...
October 3, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
H Sun, P Seres, A H Wilman
Standard functional MRI (fMRI), which includes resting-state or paradigm-driven designs, is widely used in studies of brain function, aging, and disease. These fMRI studies typically use two-dimensional gradient echo-planar imaging, which inherently contains phase data that enables quantitative susceptibility mapping (QSM). This work focuses on the dual value of QSM within fMRI studies, by providing both a localized analysis of functional changes in activated tissue, and iron-sensitive structural maps in deep grey matter (DGM)...
September 30, 2016: NMR in Biomedicine
Jin Cai, Shan Wang, Tao Li, Guorong Zhang, Guihua Bai
Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe, is a devastating disease in wheat (Triticum aestivum L.). Use of host resistance is one of the most effective strategies to minimize the disease damage. Haiyanzhong (HYZ) is a Chinese wheat landrace that shows a high level of resistance to FHB spread within a spike (type II resistance). To map the quantitative trait loci (QTLs) in HYZ and identify markers tightly linked to the QTLs for FHB resistance, a population of 172 recombinant inbred lines (RILs) from a cross between HYZ and Wheaton (FHB susceptible) was genotyped using simple sequence repeats (SSRs) and single-nucleotide polymorphisms (SNPs) derived from genotyping-by-sequencing (GBS), and evaluated for percentage of symptomatic spikelets (PSSs) per spike in three greenhouse experiments...
2016: PloS One
Mumta Chhetri, Harbans Bariana, Pakeerathan Kandiah, Urmil Bansal
The quantitative trait loci QYr.sun-3BS and QYr.sun-4DL were identified in the W195/BTSS recombinant inbred line (RIL) population in a previous study. QYr.sun-3BS explained 34 to 59% phenotypic variation in stripe rust response. We evaluated parental genotypes at different growth stages and temperature regimes to detect the critical stage for expression of QYr.sun-3BS. W195 expressed low infection type (IT) ;1C at the fourth leaf stage, when incubated at 21 ± 2°C and the alternate parent BTSS was susceptible (IT 3(+))...
September 26, 2016: Phytopathology
Takuya Hinoda, Yasutaka Fushimi, Tomohisa Okada, Yoshiki Arakawa, Chunlei Liu, Akira Yamamoto, Tsutomu Okada, Kazumichi Yoshida, Susumu Miyamoto, Kaori Togashi
PURPOSE: Gadolinium deposition in dentate nucleus (DN) has been reported after serial administration of gadolinium-based contrast agents (GBCAs). Gadolinium complexes have paramagnetic properties; therefore, we evaluated susceptibility changes of gadolinium deposition in DN using quantitative susceptibility mapping (QSM) for patients after serial administration of GBCAs. MATERIALS AND METHODS: In all, 48 patients with brain tumors, who had had serial GBCA administrations (GBCA group), and 48 healthy volunteers without any history of GBCA administrations (non-GBCA group) were enrolled in this study...
September 24, 2016: Journal of Magnetic Resonance Imaging: JMRI
Noemie Prat, Camille Guilbert, Ursa Prah, Elisabeth Wachter, Barbara Steiner, Thierry Langin, Olivier Robert, Hermann Buerstmayr
The QTL Fhb1 was successfully introgressed and validated in three durum wheat populations. The novel germplasm and the QTL detected will support improvement of Fusarium resistance in durum wheat. Durum wheat (Triticum durum Desf.) is particularly susceptible to Fusarium head blight (FHB) and breeding for resistance is hampered by limited genetic variation within this species. To date, resistant sources are mainly available in a few wild relative tetraploid wheat accessions. In this study, the effect of the well-known hexaploid wheat (Triticum aestivum L...
September 23, 2016: TAG. Theoretical and Applied Genetics. Theoretische und Angewandte Genetik
Guangjun Guo, Shubin Wang, Jinbing Liu, Baogui Pan, Weiping Diao, Wei Ge, Changzhou Gao, John C Snyder
Next-generation sequencing enabled a fast discovery of QTLs controlling CMV resistant in pepper. The gene CA02g19570 as a possible candidate gene of qCmr2.1 was identified for resistance to CMV in pepper. Cucumber mosaic virus (CMV) is one of the most important viruses infecting pepper, but the genetic basis of CMV resistance in pepper is elusive. In this study, we identified a candidate gene for CMV resistance QTL, qCmr2.1 through SLAF-seq. Segregation analysis in F2, BC1 and F2:3 populations derived from a cross between two inbred lines 'PBC688' (CMV-resistant) and 'G29' (CMV-susceptible) suggested quantitative inheritance of resistance to CMV in pepper...
September 20, 2016: TAG. Theoretical and Applied Genetics. Theoretische und Angewandte Genetik
R Abdul Fiyaz, Ashutosh K Yadav, S Gopala Krishnan, Ranjith K Ellur, Bishnu M Bashyal, Nitasha Grover, Prolay K Bhowmick, M Nagarajan, K K Vinod, Nagendra K Singh, Kumble V Prabhu, Ashok K Singh
BACKGROUND: Bakanae or foot rot disease caused by Fusarium fujikuroi [teleomorph: Gibberella fujikuroi (Sawada) Ito] is emerging as a serious disease in rice. The disease causes both quantitative and qualitative losses to the grains under the field conditions. Breeding for resistance to Bakanae disease is a promising strategy to manage this emerging disease. In this study, we used a population of 168 F14 recombinant inbred lines (RILs) derived from two indica rice parents Pusa 1342, a highly resistant variety and Pusa Basmati 1121, a highly susceptible variety to map quantitative trait loci (QTLs) governing resistance against Bakanae disease...
December 2016: Rice
Christian Langkammer, Lukas Pirpamer, Stephan Seiler, Andreas Deistung, Ferdinand Schweser, Sebastian Franthal, Nina Homayoon, Petra Katschnig-Winter, Mariella Koegl-Wallner, Tamara Pendl, Eva Maria Stoegerer, Karoline Wenzel, Franz Fazekas, Stefan Ropele, Jürgen Rainer Reichenbach, Reinhold Schmidt, Petra Schwingenschuh
BACKGROUND: Quantitative susceptibility mapping (QSM) and R2* relaxation rate mapping have demonstrated increased iron deposition in the substantia nigra of patients with idiopathic Parkinson's disease (PD). However, the findings in other subcortical deep gray matter nuclei are converse and the sensitivity of QSM and R2* for morphological changes and their relation to clinical measures of disease severity has so far been investigated only sparsely. METHODS: The local ethics committee approved this study and all subjects gave written informed consent...
2016: PloS One
Sarah Eskreis-Winkler, Dong Zhou, Tian Liu, Ajay Gupta, Susan A Gauthier, Yi Wang, Pascal Spincemaille
PURPOSE: Zero padding is a well-studied interpolation technique that improves image visualization without increasing image resolution. This interpolation is often performed as a last step before images are displayed on clinical workstations. Here, we seek to demonstrate the importance of zero padding before rather than after performing non-linear post-processing algorithms, such as Quantitative Susceptibility Mapping (QSM). To do so, we evaluate apparent spatial resolution, relative error and depiction of multiple sclerosis (MS) lesions on images that were zero padded prior to, in the middle of, and after the application of the QSM algorithm...
August 29, 2016: Magnetic Resonance Imaging
Claire Palles, John M Findlay, Ian Tomlinson
Eight loci have been identified by the two genome-wide association studies of Barrett's esophagus that have been conducted to date. Esophageal adenocarcinoma cases were included in the second study following evidence that predisposing genetic variants for this cancer overlap with those for Barrett's esophagus. Genes with roles in embryonic development of the foregut are adjacent to 6 of the loci identified (FOXF1, BARX1, FOXP1, GDF7, TBX5, and ALDH1A2). An additional locus maps to a gene with known oncogenic potential (CREB-regulated transcription coactivator 1), but expression quantitative trait data implicates yet another gene involved in esophageal development (PBX4)...
2016: Advances in Experimental Medicine and Biology
Virender Singh, Gyanendra Singh, A Chaudhury, Ashish Ojha, B S Tyagi, A K Chowdhary, Sonia Sheoran
Spot blotch is a major foliar disease of wheat caused by Bipolaris sorokiniana in warm and humid environments of the world including South Asian countries. In India, it has a larger impact in Indo-Gangetic plains of the country. Therefore, the present study was undertaken to phenotype a mapping population at different hot spots of India and to detect quantitative trait loci (QTL) for resistance to spot blotch in wheat. For this study, 209 single seed descent (SSD) derived F8, F9, F10 recombinant inbred lines (RILs) of the cross 'Sonalika' (an Indian susceptible cultivar)/'BH 1146' (a Brazilian resistant cultivar) were assessed for spot blotch resistance at two hot spot locations (Coochbehar and Kalyani) for three years and for two years under controlled conditions in the polyhouse (Karnal)...
November 2016: Molecular Biology Reports
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