Publications by authors named "Wei-Tang Chang"

29 Publications

  • Page 1 of 1

Rutin and Gallic Acid Regulates Mitochondrial Functions via the SIRT1 Pathway in C2C12 Myotubes.

Antioxidants (Basel) 2021 Feb 13;10(2). Epub 2021 Feb 13.

Department of Nutrition, Chung Shan Medical University, Taichung 40201, Taiwan.

Mitochondria are highly dynamic organelles, balancing synthesis and degradation in response to increases in mitochondrial turnover (i.e., biogenesis, fusion, fission, and mitophagy) and function. The aim of this study was to investigate the role of polyphenols in the regulation of mitochondrial functions and dynamics in C2C12 myotubes and their molecular mechanisms. Our results indicate that gallic acid and rutin are the most potential polyphenol compounds in response to 15 phenolic acids and 5 flavonoids. Gallic acid and rutin were associated with a significantly greater mitochondrial DNA ( and ), mitochondrial enzymatic activities (including citrate synthase and cytochrome oxidase), and intracellular ATP levels in C2C12 myotubes. Moreover, gallic acid and rutin significantly increased the gene expressions of mitochondrial turnover in C2C12 myotubes. Our findings indicated that gallic acid and rutin may have a beneficial effect on mitochondrial dynamics via regulation of the SIRT1-associated pathway in C2C12 myotubes.
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http://dx.doi.org/10.3390/antiox10020286DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7918168PMC
February 2021

Dysfunction in nonsense-mediated decay, protein homeostasis, mitochondrial function, and brain connectivity in ALS-FUS mice with cognitive deficits.

Acta Neuropathol Commun 2021 01 6;9(1). Epub 2021 Jan 6.

Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117549, Singapore.

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) represent two ends of the same disease spectrum of adult-onset neurodegenerative diseases that affect the motor and cognitive functions, respectively. Multiple common genetic loci such as fused in sarcoma (FUS) have been identified to play a role in ALS and FTD etiology. Current studies indicate that FUS mutations incur gain-of-toxic functions to drive ALS pathogenesis. However, how the disease-linked mutations of FUS affect cognition remains elusive. Using a mouse model expressing an ALS-linked human FUS mutation (R514G-FUS) that mimics endogenous expression patterns, we found that FUS proteins showed an age-dependent accumulation of FUS proteins despite the downregulation of mouse FUS mRNA by the R514G-FUS protein during aging. Furthermore, these mice developed cognitive deficits accompanied by a reduction in spine density and long-term potentiation (LTP) within the hippocampus. At the physiological expression level, mutant FUS is distributed in the nucleus and cytosol without apparent FUS aggregates or nuclear envelope defects. Unbiased transcriptomic analysis revealed a deregulation of genes that cluster in pathways involved in nonsense-mediated decay, protein homeostasis, and mitochondrial functions. Furthermore, the use of in vivo functional imaging demonstrated widespread reduction in cortical volumes but enhanced functional connectivity between hippocampus, basal ganglia and neocortex in R514G-FUS mice. Hence, our findings suggest that disease-linked mutation in FUS may lead to changes in proteostasis and mitochondrial dysfunction that in turn affect brain structure and connectivity resulting in cognitive deficits.
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http://dx.doi.org/10.1186/s40478-020-01111-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7789430PMC
January 2021

Effect of Astaxanthin on the Inhibition of Lipid Accumulation in 3T3-L1 Adipocytes via Modulation of Lipogenesis and Fatty Acid Transport Pathways.

Molecules 2020 Aug 7;25(16). Epub 2020 Aug 7.

Department of Nutrition, Chung Shan Medical University, Taichung 40201, Taiwan.

Obesity is defined as a condition of excessive fat tissue accumulation. It was the major factor most closely associated with lifestyle-related diseases. In the present study, we investigated the effect of astaxanthin on the inhibition of lipid accumulation in 3T3-L1 adipocytes. 3T3-L1 adipocytes were treated with 0-25 µg/mL of astaxanthin for 0-48 h. The result indicated that astaxanthin significantly decreased the oil Red O stained material (OROSM), intracellular triglyceride accumulation, and glycerol 3-phosphate dehydrogenase (GPDH) activity in 3T3-L1 adipocytes ( < 0.05). At the molecular level, astaxanthin significantly down-regulated the mRNA expression of () in 3T3-L1 adipocytes ( < 0.05). Moreover, target genes of on the inhibition of lipogenesis, such as (), (), (), (), and () in 3T3-L1 adipocytes were significantly down-regulated at a time-dependent manner ( < 0.05). These results suggested that astaxanthin efficiently suppressed lipid accumulation in 3T3-L1 adipocytes and its action is associated with the down-regulation of lipogenesis-related genes and the triglyceride accumulation in 3T3-L1 adipocytes. Therefore, astaxanthin can be developed as a potential nutraceutical ingredient for the prevention of obesity in a niche market.
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http://dx.doi.org/10.3390/molecules25163598DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7466122PMC
August 2020

High-resolution 3D MR Fingerprinting using parallel imaging and deep learning.

Neuroimage 2020 02 2;206:116329. Epub 2019 Nov 2.

Departments of Radiology, University of North Carolina, Chapel Hill, NC, USA; Biomedical Research Imaging Center (BRIC), University of North Carolina at Chapel Hill, North Carolina, USA. Electronic address:

MR Fingerprinting (MRF) is a relatively new imaging framework capable of providing accurate and simultaneous quantification of multiple tissue properties for improved tissue characterization and disease diagnosis. While 2D MRF has been widely available, extending the method to 3D MRF has been an actively pursued area of research as a 3D approach can provide a higher spatial resolution and better tissue characterization with an inherently higher signal-to-noise ratio. However, 3D MRF with a high spatial resolution requires lengthy acquisition times, especially for a large volume, making it impractical for most clinical applications. In this study, a high-resolution 3D MR Fingerprinting technique, combining parallel imaging and deep learning, was developed for rapid and simultaneous quantification of T and T relaxation times. Parallel imaging was first applied along the partition-encoding direction to reduce the amount of acquired data. An advanced convolutional neural network was then integrated with the MRF framework to extract features from the MRF signal evolution for improved tissue characterization and accelerated mapping. A modified 3D-MRF sequence was also developed in the study to acquire data to train the deep learning model that can be directly applied to prospectively accelerate 3D MRF scans. Our results of quantitative T and T maps demonstrate that improved tissue characterization can be achieved using the proposed method as compared to prior methods. With the integration of parallel imaging and deep learning techniques, whole-brain (26 × 26 × 18 cm) quantitative T and T mapping with 1-mm isotropic resolution were achieved in ~7 min. In addition, a ~7-fold improvement in processing time to extract tissue properties was also accomplished with the deep learning approach as compared to the standard template matching method. All of these improvements make high-resolution whole-brain quantitative MR imaging feasible for clinical applications.
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http://dx.doi.org/10.1016/j.neuroimage.2019.116329DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7136033PMC
February 2020

Common functional networks in the mouse brain revealed by multi-centre resting-state fMRI analysis.

Neuroimage 2020 01 12;205:116278. Epub 2019 Oct 12.

Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada; Department of Psychiatry, McGill University, Montreal, Quebec, Canada; Department of Biological and Biomedical Engineering, McGill University, Montreal, Quebec, Canada.

Preclinical applications of resting-state functional magnetic resonance imaging (rsfMRI) offer the possibility to non-invasively probe whole-brain network dynamics and to investigate the determinants of altered network signatures observed in human studies. Mouse rsfMRI has been increasingly adopted by numerous laboratories worldwide. Here we describe a multi-centre comparison of 17 mouse rsfMRI datasets via a common image processing and analysis pipeline. Despite prominent cross-laboratory differences in equipment and imaging procedures, we report the reproducible identification of several large-scale resting-state networks (RSN), including a mouse default-mode network, in the majority of datasets. A combination of factors was associated with enhanced reproducibility in functional connectivity parameter estimation, including animal handling procedures and equipment performance. RSN spatial specificity was enhanced in datasets acquired at higher field strength, with cryoprobes, in ventilated animals, and under medetomidine-isoflurane combination sedation. Our work describes a set of representative RSNs in the mouse brain and highlights key experimental parameters that can critically guide the design and analysis of future rodent rsfMRI investigations.
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http://dx.doi.org/10.1016/j.neuroimage.2019.116278DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7116112PMC
January 2020

Differential inhibitory effects of resveratrol on excitotoxicity and synaptic plasticity: involvement of NMDA receptor subtypes.

Nutr Neurosci 2021 Jun 22;24(6):443-458. Epub 2019 Jul 22.

Institute of Neuroscience, National Chengchi University, Taipei, Taiwan.

The neuroprotective effects of resveratrol against excitatory neurotoxicity have been associated with N-methyl-D-aspartate receptor (NMDAR) inhibition. This study examined the differential inhibitory effects of resveratrol on NMDAR-mediated responses in neuronal cells with different NMDAR subtype composition. The effects of resveratrol on NMDA-induced cell death and calcium influx in immature and mature rat primary cortical neurons were determined and compared. Moreover, the potencies and efficacies of resveratrol to inhibit NR1/NR2A, NR1/NR2B, NR1/NR2C, and NR1/NR2D NMDAR expressed in HEK 293 cells were evaluated. Resveratrol significantly attenuated NMDA-induced cell death in mature neurons, but not in immature neurons. Resveratrol also concentration-dependently reduced NMDA-induced calcium influx among all NMDAR subtypes, but displayed NR2 subunit selectivity, with a potency rank order of NR2B = NR2D > NR2A = NR2C and an efficacy rank order of NR2B = NR2C > NR2A = NR2D. Data show the stronger inhibitory effects of resveratrol on NR1/NR2B than other subtypes. Moreover, resveratrol did not affect hippocampal long-term potentiation (LTP), but impaired long-term depression (LTD). These findings reveal the specific NMDAR modulating profile of resveratrol, providing further insight into potential mechanisms underlying the protective effects of resveratrol on neurological disorders.
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http://dx.doi.org/10.1080/1028415X.2019.1641995DOI Listing
June 2021

Evaluation of nuisance removal for functional MRI of rodent brain.

Neuroimage 2019 03 26;188:694-709. Epub 2018 Dec 26.

Singapore Bioimaging Consortium, Agency for Science Technology and Research, Singapore.

Functional MRI (fMRI) has become an important translational tool for studying brain activity and connectivity in animal models and humans. For accurate and reliable measurement of functional connectivity, nuisance removal strategies developed for human brain, such as regressing motion parameters, cerebrospinal fluid (CSF)/white matter-derived signals and the global signal, have been applied to rodent. However, due to the very different anatomy, with the majority of the rodent brain being gray matter, and experimental conditions, in which animals are anesthetized and head-fixed, these methods may not be suitable for rodent fMRI. In this study, we assessed various nuisance regression methods and the effects of motion correction on a large dataset of both task and resting fMRI of anesthetized rat brain. Sensitivity and specificity were assessed in the somatosensory pathway under forepaw stimulation and resting state. Reproducibility at various sample sizes was simulated by randomly subsampling the dataset. To overcome the difficulty in extracting nuisance from the brain, a method using principal components estimated from tissues outside the brain was evaluated. Our results showed that neither detrend, motion correction, motion regression nor CSF signal regression could improve specificity despite increasing temporal signal-to-noise ratios. Although global signal regression increased the specificity of task activation and functional connectivity, the sensitivity and connectivity strength was drastically reduced, likely due to its strong correlation with the cortical signal. Motion parameters also correlated with task activation and the global signal, indicating that motion correction detected intensity variations in the brain. The nuisance estimated from tissues outside the brain produced a moderate improvement in specificity. In conclusion, nuisance removal suitable for human fMRI may not be optimal for rodents. While further development is needed, estimating nuisance from tissues outside the brain may be an alternative.
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http://dx.doi.org/10.1016/j.neuroimage.2018.12.048DOI Listing
March 2019

Connectomic imaging reveals Huntington-related pathological and pharmaceutical effects in a mouse model.

NMR Biomed 2018 12 27;31(12):e4007. Epub 2018 Sep 27.

Singapore BioImaging Consortium, Agency for Science, Technology and Research, Singapore, Singapore.

Recent studies suggest that neurodegenerative diseases could affect brain structure and function in disease-specific network patterns; however, how spontaneous activity affects structural covariance network (SC) is not clear. We hypothesized that hyper-excitability in Huntington disease (HD) disrupts the coordinated structural and functional connectivity, and treatment with memantine helps to reduce excitotoxicity and normalize the connectivity. MRI was conducted to measure somatosensory activation, resting-state functional-connectivity (rsFC), SC, amplitude of low frequency fluctuation (ALFF) and ALFF covariance (ALFFC) in the YAC128 mouse model of HD. We found somatosensory activation was unchanged but the subcortical ALFF was increased in HD mice, indicating subcortical but not cortical hyperactivity. The reduced sensorimotor rsFC but spared hippocampal and default mode networks in the HD mice was consistent with the more pronounced impairment in motor function compared with cognitive performance. The disease suppressed SC globally and reduced ALFFC in the basal ganglia network as well as its anti-correlation with the default mode network. By comparing these connectivity measures, we found that the originally coupled rsFC-SC relationship was impaired whereas SC-ALFFC correlation was increased by HD, suggesting disease facilitated covariation of brain volume and activity amplitude but not neural synchrony. The comparison with mono-synaptic axonal projection supports the hypothesis that rsFC, but not SC or ALFFC, is highly dependent on structural connectivity under healthy conditions. Treatment with memantine had a strong effect on normalizing the SC and reducing ALFF while slightly increasing other connectivity measures and restoring the rsFC-SC coupling, which is consistent with its effect on alleviating hyper-excitability and improving the coordinated neural growth. These results indicate that HD affects the cerebral structure-function relationship which could be partially reverted by NMDA antagonism. These connectivity measures provide unique insights into pathological and pharmaceutical effects in brain circuitry, and could be translatable biomarkers for evaluating drug effect and refining its efficacy.
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http://dx.doi.org/10.1002/nbm.4007DOI Listing
December 2018

Antioxidant activity and anticancer effect of ethanolic and aqueous extracts of the roots of Ficus beecheyana and their phenolic components.

J Food Drug Anal 2018 01 16;26(1):182-192. Epub 2017 Mar 16.

School of Nutrition, Chung Shan Medical University, Taichung, Taiwan; Department of Nutrition, Chung Shan Medical University Hospital, Taichung, Taiwan. Electronic address:

This study aimed to investigate the antioxidant and anticancer effects of ethanolic and aqueous extracts of the roots of Ficus beecheyana (EERFB and AERFB) and their phenolic components. In this study, total phenolic content and antioxidant activity of EERFB were higher than those of AERFB. Major phenolic compounds in the extracts were gallic acid, p-hydroxybenzoic acid, caffeic acid, chlorogenic acid, p-coumaric acid, and rutin; which were identified by high-performance liquid chromatography. Flow cytometric analysis of HL-60 cells exposed to EERFB showed that the percentage of apoptotic cells increased in a dose-dependent manner. EERFB treatment resulted in the loss of mitochondrial membrane potential and induced the apoptosis of HL-60 cells through a Fas- and mitochondrial-mediated pathway. Finally, pretreatment with general caspase-9/-3 inhibitors prevented EERFB from inhibiting cell viability in HL-60 cells. Our finding suggests that EERFB is an agent that may have antioxidant activity and inhibit the growth of cancer cells.
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http://dx.doi.org/10.1016/j.jfda.2017.02.002DOI Listing
January 2018

Antiobesity Efficacy of Quercetin-Rich Supplement on Diet-Induced Obese Rats: Effects on Body Composition, Serum Lipid Profile, and Gene Expression.

J Agric Food Chem 2018 Jan 26;66(1):70-80. Epub 2017 Dec 26.

Department of Nutrition, Chung Shan Medical University , Taichung, Taiwan.

The antiobesity effects of quercetin-rich supplement (QRS), which contain quercetin, lycopene, taurine, and litchi flower extract, on a high-fat diet (HFD)-induced obese rats were investigated. The rats that consume HFD with QRS (185 mg/kg rat) have significantly modulated the final body weights [490 ± 11 (HFD) → 441 ± 11 (HFD+QRS) g], total body fat [112.9 ± 4.5 (HFD) → 86.6 ± 5.7 (HFD+QRS) g], liver weights [14.8 ± 0.4 (HFD) → 12.6 ± 0.4 (HFD+QRS) g/rat], and the serum TG [102.5 ± 7.3 (HFD) → 90.7 ± 6.5 (HFD+QRS) mg/dL] to a level that resembled the regular diet-consumed rats (p < 0.05). The excretion of lipid in the faeces augmented in QRS groups as compared with the nonsupplemented HFD group [faecal total lipid: 62.43 ± 2.80 (HFD) → 73.15 ± 0.88 (HFD+QRS) mg/g dried faeces, p < 0.05]. In the histological analysis, quercetin-rich formulation supplemented groups presented a much less lipid accumulation and smaller size of adipocytes. Moreover, a decreased serum thiobarbituric acid reactive substances [1.55 ± 0.17 (HFD) → 0.78 ± 0.04 (HFD+QRS) nmol MDA eq/mL serum] increased levels of serum Trolox equivalent antioxidant capacity [3.89 ± 0.08 (HFD) → 6.46 ± 0.20 (HFD+QRS) μmol/mL serum], and more active hepatic antioxidant enzymes were observed in the supplemented groups (p < 0.05). The result of this work is a good demonstration of how a combination of bioactive compounds could work synergistically and become very effective in disease prevention.
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http://dx.doi.org/10.1021/acs.jafc.7b03551DOI Listing
January 2018

Deep Sea Water Improves Abnormalities in Lipid Metabolism through Lipolysis and Fatty Acid Oxidation in High-Fat Diet-Induced Obese Rats.

Mar Drugs 2017 Dec 11;15(12). Epub 2017 Dec 11.

School of Nutrition, Chung Shan Medical University, Taichung 404, Taiwan.

Deep sea water (DSW) is a natural marine resource that has been utilized for food, agriculture, cosmetics, and medicine. The aim of this study was to investigate whether DSW has beneficial lipid metabolic effects in an animal model. Our previous in vitro study indicated that DSW significantly decreased the intracellular triglyceride and glycerol-3-phosphate dehydrogenase activity in 3T3-L1 adipocytes. DSW also inhibited the gene levels of adipocyte differentiation, lipogenesis, and adipocytokines, and up-regulated gene levels of lipolysis and fatty acid oxidation. In the present study, the results showed that body weight, liver, adipose tissue, hepatic triglycerides and cholesterol, and serum parameters in the high-fat diet (HFD) + DSW groups were significantly lower compared to the HFD group. Moreover, the fecal output of total lipids, triglycerides, and cholesterol in the HFD + DSW groups was significantly higher than that of the HFD group. Regarding gene expression, DSW significantly increased the gene levels of lipolysis and fatty acid oxidation, and decreased the gene levels of adipocytokine in the adipose tissue of rats with HFD-induced obesity. These results indicate a potential molecular mechanism by which DSW can suppress obesity in rats with HFD-induced obesity through lipolysis and fatty acid oxidation.
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http://dx.doi.org/10.3390/md15120386DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5742846PMC
December 2017

Suppression of irrelevant sounds during auditory working memory.

Neuroimage 2017 11 14;161:1-8. Epub 2017 Aug 14.

Harvard Medical School - Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA.

Auditory working memory (WM) processing in everyday acoustic environments depends on our ability to maintain relevant information online in our minds, and to suppress interference caused by competing incoming stimuli. A challenge in communication settings is that the relevant content and irrelevant inputs may emanate from a common source, such as a talkative conversationalist. An open question is how the WM system deals with such interference. Will the distracters become inadvertently filtered before processing for meaning because the primary WM operations deplete all available processing resources? Or are they suppressed post perceptually, through an active control process? We tested these alternative hypotheses by measuring magnetoencephalography (MEG), EEG, and functional MRI (fMRI) during a phonetic auditory continuous performance task. Contextual WM maintenance load was manipulated by adjusting the number of "filler" letter sounds in-between cue and target letter sounds. Trial-to-trial variability of pre- and post-stimulus activations in fMRI-informed cortical MEG/EEG estimates was analyzed within and across 14 subjects using generalized linear mixed effect (GLME) models. High contextual WM maintenance load suppressed left auditory cortex (AC) activations around 250-300 ms after the onset of irrelevant phonetic sounds. This effect coincided with increased 10-14 Hz alpha-range oscillatory functional connectivity between the left dorsolateral prefrontal cortex (DLPFC) and left AC. Suppression of AC responses to irrelevant sounds during active maintenance of the task context also correlated with increased pre-stimulus 7-15 Hz alpha power. Our results suggest that under high auditory WM load, irrelevant sounds are suppressed through a "late" active suppression mechanism, which prevents short-term consolidation of irrelevant information without affecting the initial screening of potentially meaningful stimuli. The results also suggest that AC alpha oscillations play an inhibitory role during auditory WM processing.
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http://dx.doi.org/10.1016/j.neuroimage.2017.08.040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5696107PMC
November 2017

Intracortical depth analyses of frequency-sensitive regions of human auditory cortex using 7TfMRI.

Neuroimage 2016 Dec 5;143:116-127. Epub 2016 Sep 5.

Harvard Medical School - Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA.

Despite recent advances in auditory neuroscience, the exact functional organization of human auditory cortex (AC) has been difficult to investigate. Here, using reversals of tonotopic gradients as the test case, we examined whether human ACs can be more precisely mapped by avoiding signals caused by large draining vessels near the pial surface, which bias blood-oxygen level dependent (BOLD) signals away from the actual sites of neuronal activity. Using ultra-high field (7T) fMRI and cortical depth analysis techniques previously applied in visual cortices, we sampled 1mm isotropic voxels from different depths of AC during narrow-band sound stimulation with biologically relevant temporal patterns. At the group level, analyses that considered voxels from all cortical depths, but excluded those intersecting the pial surface, showed (a) the greatest statistical sensitivity in contrasts between activations to high vs. low frequency sounds and (b) the highest inter-subject consistency of phase-encoded continuous tonotopy mapping. Analyses based solely on voxels intersecting the pial surface produced the least consistent group results, even when compared to analyses based solely on voxels intersecting the white-matter surface where both signal strength and within-subject statistical power are weakest. However, no evidence was found for reduced within-subject reliability in analyses considering the pial voxels only. Our group results could, thus, reflect improved inter-subject correspondence of high and low frequency gradients after the signals from voxels near the pial surface are excluded. Using tonotopy analyses as the test case, our results demonstrate that when the major physiological and anatomical biases imparted by the vasculature are controlled, functional mapping of human ACs becomes more consistent from subject to subject than previously thought.
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http://dx.doi.org/10.1016/j.neuroimage.2016.09.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5124525PMC
December 2016

Combined MEG and EEG show reliable patterns of electromagnetic brain activity during natural viewing.

Neuroimage 2015 Jul 2;114:49-56. Epub 2015 Apr 2.

Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.

Naturalistic stimuli such as movies are increasingly used to engage cognitive and emotional processes during fMRI of brain hemodynamic activity. However, movies have been little utilized during magnetoencephalography (MEG) and EEG that directly measure population-level neuronal activity at a millisecond resolution. Here, subjects watched a 17-min segment from the movie Crash (Lionsgate Films, 2004) twice during simultaneous MEG/EEG recordings. Physiological noise components, including ocular and cardiac artifacts, were removed using the DRIFTER algorithm. Dynamic estimates of cortical activity were calculated using MRI-informed minimum-norm estimation. To improve the signal-to-noise ratio (SNR), principal component analyses (PCA) were employed to extract the prevailing temporal characteristics within each anatomical parcel of the Freesurfer Desikan-Killiany cortical atlas. A variety of alternative inter-subject correlation (ISC) approaches were then utilized to investigate the reliability of inter-subject synchronization during natural viewing. In the first analysis, the ISCs of the time series of each anatomical region over the full time period across all subject pairs were calculated and averaged. In the second analysis, dynamic ISC (dISC) analysis, the correlation was calculated over a sliding window of 200 ms with 3.3 ms steps. Finally, in a between-run ISC analysis, the between-run correlation was calculated over the dynamic ISCs of the two different runs after the Fisher z-transformation. Overall, the most reliable activations occurred in occipital/inferior temporal visual and superior temporal auditory cortices as well as in the posterior cingulate, precuneus, pre- and post-central gyri, and right inferior and middle frontal gyri. Significant between-run ISCs were observed in superior temporal auditory cortices and inferior temporal visual cortices. Taken together, our results show that movies can be utilized as naturalistic stimuli in MEG/EEG similarly as in fMRI studies.
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http://dx.doi.org/10.1016/j.neuroimage.2015.03.066DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4446182PMC
July 2015

Cytotoxic and apoptotic effects of caffeate derivatives on A549 human lung carcinoma cells.

J Chin Med Assoc 2014 Oct 19;77(10):535-43. Epub 2014 Aug 19.

School of Nutrition, Chung Shan Medical University, Taichung, Taiwan, ROC; Department of Nutrition, Chung Shan Medical University Hospital, Taichung, Taiwan, ROC. Electronic address:

Background: Caffeate derivatives have been reported to exhibit antioxidant, anti-inflammatory, and anticancer activities. To reveal the cytotoxic and apoptotic effects of caffeate derivatives, we studied the effects of octyl, phenylpropyl, and decyl caffeates on cell growth and apoptosis in A549 human lung carcinoma cells.

Methods: A549 human lung carcinoma cells were treated with 0-100 μM of caffeate derivatives for 0-48 hours. The cytotoxic and apoptotic effects were evaluated by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay for cell viability, propidium iodide staining method for cell morphology, mitochondrial membrane potential analysis, and Western blot for protein expression.

Results: Octyl, phenylpropyl, and decyl caffeates all significantly decreased the cell viability of A549 cells with 50% inhibitory concentration values of 54.2 ± 10.1 μM, 80.2 ± 1.3 μM, and 74.9 ± 2.1 μM, respectively. Propidium iodide staining revealed that apoptotic bodies appeared when cells were treated with octyl and decyl caffeates. Treatment of A549 cells with octyl and decyl caffeates caused the loss of mitochondria membrane potential. Western blots revealed that octyl and decyl caffeates stimulate an increase in the protein levels of Fas, FasL, and Apaf-1. Moreover, these compounds changed the levels of pro- and antiapoptotic Bcl-2 family members and induced the activation of caspase-12, -9, and -3, which was followed by cleavage of poly (ADP-ribose) polymerase.

Conclusion: These results demonstrate that octyl and decyl caffeates induce cell apoptosis in A549 human lung carcinoma cells.
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http://dx.doi.org/10.1016/j.jcma.2014.05.011DOI Listing
October 2014

Improving the spatial resolution of magnetic resonance inverse imaging via the blipped-CAIPI acquisition scheme.

Neuroimage 2014 May 27;91:401-11. Epub 2013 Dec 27.

Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan. Electronic address:

Using simultaneous acquisition from multiple channels of a radio-frequency (RF) coil array, magnetic resonance inverse imaging (InI) achieves functional MRI acquisitions at a rate of 100ms per whole-brain volume. InI accelerates the scan by leaving out partition encoding steps and reconstructs images by solving under-determined inverse problems using RF coil sensitivity information. Hence, the correlated spatial information available in the coil array causes spatial blurring in the InI reconstruction. Here, we propose a method that employs gradient blips in the partition encoding direction during the acquisition to provide extra spatial encoding in order to better differentiate signals from different partitions. According to our simulations, this blipped-InI (bInI) method can increase the average spatial resolution by 15.1% (1.3mm) across the whole brain and from 32.6% (4.2mm) in subcortical regions, as compared to the InI method. In a visual fMRI experiment, we demonstrate that, compared to InI, the spatial distribution of bInI BOLD response is more consistent with that of a conventional echo-planar imaging (EPI) at the level of individual subjects. With the improved spatial resolution, especially in subcortical regions, bInI can be a useful fMRI tool for obtaining high spatiotemporal information for clinical and cognitive neuroscience studies.
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http://dx.doi.org/10.1016/j.neuroimage.2013.12.037DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4086630PMC
May 2014

Lateralized parietotemporal oscillatory phase synchronization during auditory selective attention.

Neuroimage 2014 Feb 31;86:461-9. Epub 2013 Oct 31.

Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA. Electronic address:

Based on the infamous left-lateralized neglect syndrome, one might hypothesize that the dominating right parietal cortex has a bilateral representation of space, whereas the left parietal cortex represents only the contralateral right hemispace. Whether this principle applies to human auditory attention is not yet fully clear. Here, we explicitly tested the differences in cross-hemispheric functional coupling between the intraparietal sulcus (IPS) and auditory cortex (AC) using combined magnetoencephalography (MEG), EEG, and functional MRI (fMRI). Inter-regional pairwise phase consistency (PPC) was analyzed from data obtained during dichotic auditory selective attention task, where subjects were in 10-s trials cued to attend to sounds presented to one ear and to ignore sounds presented in the opposite ear. Using MEG/EEG/fMRI source modeling, parietotemporal PPC patterns were (a) mapped between all AC locations vs. IPS seeds and (b) analyzed between four anatomically defined AC regions-of-interest (ROI) vs. IPS seeds. Consistent with our hypothesis, stronger cross-hemispheric PPC was observed between the right IPS and left AC for attended right-ear sounds, as compared to PPC between the left IPS and right AC for attended left-ear sounds. In the mapping analyses, these differences emerged at 7-13Hz, i.e., at the theta to alpha frequency bands, and peaked in Heschl's gyrus and lateral posterior non-primary ACs. The ROI analysis revealed similarly lateralized differences also in the beta and lower theta bands. Taken together, our results support the view that the right parietal cortex dominates auditory spatial attention.
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http://dx.doi.org/10.1016/j.neuroimage.2013.10.043DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3908553PMC
February 2014

Basic amino acid residues of human eosinophil derived neurotoxin essential for glycosaminoglycan binding.

Int J Mol Sci 2013 Sep 16;14(9):19067-85. Epub 2013 Sep 16.

Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu 300, Taiwan.

Human eosinophil derived neurotoxin (EDN), a granule protein secreted by activated eosinophils, is a biomarker for asthma in children. EDN belongs to the human RNase A superfamily possessing both ribonucleolytic and antiviral activities. EDN interacts with heparin oligosaccharides and heparin sulfate proteoglycans on bronchial epithelial Beas-2B cells. In this study, we demonstrate that the binding of EDN to cells requires cell surface glycosaminoglycans (GAGs), and the binding strength between EDN and GAGs depends on the sulfation levels of GAGs. Furthermore, in silico computer modeling and in vitro binding assays suggest critical roles for the following basic amino acids located within heparin binding regions (HBRs) of EDN 34QRRCKN39 (HBR1), 65NKTRKN70 (HBR2), and 113NRDQRRD119 (HBR3) and in particular Arg35, Arg36, and Arg38 within HBR1, and Arg114 and Arg117 within HBR3. Our data suggest that sulfated GAGs play a major role in EDN binding, which in turn may be related to the cellular effects of EDN.
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http://dx.doi.org/10.3390/ijms140919067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3794821PMC
September 2013

Dynamic oscillatory processes governing cued orienting and allocation of auditory attention.

J Cogn Neurosci 2013 Nov 5;25(11):1926-43. Epub 2013 Aug 5.

Harvard Medical School-Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA.

In everyday listening situations, we need to constantly switch between alternative sound sources and engage attention according to cues that match our goals and expectations. The exact neuronal bases of these processes are poorly understood. We investigated oscillatory brain networks controlling auditory attention using cortically constrained fMRI-weighted magnetoencephalography/EEG source estimates. During consecutive trials, participants were instructed to shift attention based on a cue, presented in the ear where a target was likely to follow. To promote audiospatial attention effects, the targets were embedded in streams of dichotically presented standard tones. Occasionally, an unexpected novel sound occurred opposite to the cued ear to trigger involuntary orienting. According to our cortical power correlation analyses, increased frontoparietal/temporal 30-100 Hz gamma activity at 200-1400 msec after cued orienting predicted fast and accurate discrimination of subsequent targets. This sustained correlation effect, possibly reflecting voluntary engagement of attention after the initial cue-driven orienting, spread from the TPJ, anterior insula, and inferior frontal cortices to the right FEFs. Engagement of attention to one ear resulted in a significantly stronger increase of 7.5-15 Hz alpha in the ipsilateral than contralateral parieto-occipital cortices 200-600 msec after the cue onset, possibly reflecting cross-modal modulation of the dorsal visual pathway during audiospatial attention. Comparisons of cortical power patterns also revealed significant increases of sustained right medial frontal cortex theta power, right dorsolateral pFC and anterior insula/inferior frontal cortex beta power, and medial parietal cortex and posterior cingulate cortex gamma activity after cued versus novelty-triggered orienting (600-1400 msec). Our results reveal sustained oscillatory patterns associated with voluntary engagement of auditory spatial attention, with the frontoparietal and temporal gamma increases being best predictors of subsequent behavioral performance.
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http://dx.doi.org/10.1162/jocn_a_00452DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3788846PMC
November 2013

fMRI hemodynamics accurately reflects neuronal timing in the human brain measured by MEG.

Neuroimage 2013 Sep 13;78:372-84. Epub 2013 Apr 13.

Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.

Neuronal activation sequence information is essential for understanding brain functions. Extracting such timing information from blood oxygenation level dependent (BOLD) fMRI is confounded by interregional neurovascular differences and poorly understood relations between BOLD and electrophysiological response delays. Here, we recorded whole-head BOLD fMRI at 100 ms resolution and magnetoencephalography (MEG) during a visuomotor reaction-time task. Both methods detected the same activation sequence across five regions, from visual towards motor cortices, with linearly correlated interregional BOLD and MEG response delays. The smallest significant interregional BOLD delay was 100 ms; all delays ≥400 ms were significant. Switching the order of external events reversed the sequence of BOLD activations, indicating that interregional neurovascular differences did not confound the results. This may open new avenues for using fMRI to follow rapid activation sequences in the brain.
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http://dx.doi.org/10.1016/j.neuroimage.2013.04.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3682657PMC
September 2013

Whole-head rapid fMRI acquisition using echo-shifted magnetic resonance inverse imaging.

Neuroimage 2013 Sep 4;78:325-38. Epub 2013 Apr 4.

Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.

The acquisition time of BOLD contrast functional MRI (fMRI) data with whole-brain coverage typically requires a sampling rate of one volume in 1-3s. Although the volumetric sampling time of a few seconds is adequate for measuring the sluggish hemodynamic response (HDR) to neuronal activation, faster sampling of fMRI might allow for monitoring of rapid physiological fluctuations and detection of subtle neuronal activation timing information embedded in BOLD signals. Previous studies utilizing a highly accelerated volumetric MR inverse imaging (InI) technique have provided a sampling rate of one volume per 100 ms with 5mm spatial resolution. Here, we propose a novel modification of this technique, the echo-shifted InI, which allows TE to be longer than TR, to measure BOLD fMRI at an even faster sampling rate of one volume per 25 ms with whole-brain coverage. Compared with conventional EPI, echo-shifted InI provided an 80-fold speedup with similar spatial resolution and less than 2-fold temporal SNR loss. The capability of echo-shifted InI to detect HDR timing differences was tested empirically. At the group level (n=6), echo-spaced InI was able to detect statistically significant HDR timing differences of as low as 50 ms in visual stimulus presentation. At the level of individual subjects, significant differences in HDR timing were detected for 400 ms stimulus-onset differences. Our results also show that the temporal resolution of 25 ms is necessary for maintaining the temporal detecting capability at this level. With the capabilities of being able to distinguish the timing differences in the millisecond scale, echo-shifted InI could be a useful fMRI tool for obtaining temporal information at a time scale closer to that of neuronal dynamics.
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http://dx.doi.org/10.1016/j.neuroimage.2013.03.040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3672248PMC
September 2013

Sparse current source estimation for MEG using loose orientation constraints.

Hum Brain Mapp 2013 Sep 22;34(9):2190-201. Epub 2012 Mar 22.

Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.

Spatially focal source estimates for magnetoencephalography (MEG) and electroencephalography (EEG) data can be obtained by imposing a minimum ℓ(1) -norm constraint on the distribution of the source currents. Anatomical information about the expected locations and orientations of the sources can be included in the source models. In particular, the sources can be assumed to be oriented perpendicular to the cortical surface. We introduce a minimum ℓ(1) -norm estimation source modeling approach with loose orientation constraints (ℓ(1) LOC), which integrates the estimation of the orientation, location, and strength of the source currents into a cost function to jointly model the residual error and the ℓ(1) -norm of the source estimates. Evaluation with simulated MEG data indicated that the ℓ(1) LOC method can provide low spatial dispersion, high localization accuracy, and high source detection rates. Application to somatosensory and auditory MEG data resulted in physiologically reasonable source distributions. The proposed ℓ(1) LOC method appears useful for incorporating anatomical information about the source orientations into sparse source estimation of MEG data.
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http://dx.doi.org/10.1002/hbm.22057DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4086627PMC
September 2013

Multi-projection magnetic resonance inverse imaging of the human visuomotor system.

Neuroimage 2012 May 4;61(1):304-13. Epub 2012 Feb 4.

Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.

Using highly parallel radiofrequency (RF) detection, magnetic resonance inverse imaging (InI) can achieve 100 ms temporal resolution with whole brain coverage. This is achieved by trading off partition encoding steps and thus spatial resolution for a higher acquisition rate. The reduced spatial information is estimated by solving under-determined inverse problems using RF coil sensitivity information. Here we propose multi projection inverse imaging (mInI) to combine different projection images to improve the spatial resolution of InI. Specifically, coronal, sagittal, and transverse projection images were acquired from different runs of the fMRI acquisitions using a 32-channel head coil array. Simulations show that mInI improves the quality of the instantaneous image reconstruction significantly. Going from one projection to three projections, the spatial resolution quantified by the full width at half maximum of the point-spread function (PSF) is improved from 2.6 pixels to 1.4 pixels (4 mm nominal resolution per pixel). Considering the shape of the PSF, the effective spatial resolution is improved from 16.9 pixels to 4.7 pixels. In vivo fMRI experiments using a two-choice reaction time tasks show visual and sensorimotor cortical activities spatially consistent with typical EPI data, yet mInI offers 100 ms temporal resolution with the whole brain coverage. The mInI data with three projections revealed that the sensorimotor cortex was activated 700 ms after the visual cortex. mInI can be applied to BOLD-contrast fMRI experiments to characterize the dynamics of the activated brain areas with a high spatiotemporal resolution.
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http://dx.doi.org/10.1016/j.neuroimage.2012.01.115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3342431PMC
May 2012

Effects of polyphenolic compounds on tumor necrosis factor-α (TNF-α)-induced changes of adipokines and oxidative stress in 3T3-L1 adipocytes.

J Agric Food Chem 2011 Jan 27;59(2):546-51. Epub 2010 Dec 27.

Department of Food Science and Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan.

Over the last few decades, obesity has become a global epidemic in both developed and developing countries. Recent studies have indicated that obesity is closely associated with chronic inflammation characterized by abnormal levels of adipocytokines and inflammatory cytokines in adipocytes. The aim of this work was to study the effects of 21 polyphenolic compounds on tumor necrosis factor-α (TNF-α)-induced changes of adipokines and oxidative stress in 3T3-L1 adipocytes. The results showed that p-coumaric acid, quercetin, and resveratrol have greater inhibition (p < 0.05) of a TNF-α-induced increase in the production of interleukin-6 (IL-6) among 21 tested polyphenolic compounds. p-Coumaric acid, quercetin, and resveratrol demonstrated inhibitions of TNF-α-induced changes in levels of monocyte chemoattractant protein-1 (MCP-1), plasminogen activator inhibitor-1 (PAI-1), and intracellular reactive oxygen species (ROS) in 3T3-L1 adipocytes. Furthermore, p-coumaric acid, quercetin, and resveratrol increased levels (p < 0.05) of secreted adiponectin, superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GPx), and glutathione S-transferase (GST) in TNF-α-treated 3T3-L1 adipocytes. These results indicate that the inhibition of TNF-α-induced changes of adipokines and oxidative stress by some polyphenolic compounds might have further implications in preventing obesity-related pathologies.
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http://dx.doi.org/10.1021/jf1036992DOI Listing
January 2011

Functional magnetic resonance inverse imaging of human visuomotor systems using eigenspace linearly constrained minimum amplitude (eLCMA) beamformer.

Neuroimage 2011 Mar 4;55(1):87-100. Epub 2010 Dec 4.

Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.

Recently proposed dynamic magnetic resonance (MR) inverse imaging (InI) is a novel parallel imaging reconstruction technique capable of improving the temporal resolution of blood-oxygen level-dependent (BOLD) contrast functional MRI (fMRI) to the order of milliseconds at the cost of moderate spatial resolution. Volumetric InI reconstructs spatial information from projection data by solving ill-posed inverse problems using simultaneous acquisitions from a RF coil array. Previously a spatial filtering technique based on linearly constrained minimum variance (LCMV) beamformer was suggested to localize the hemodynamic changes of dynamic InI data with improved spatial resolution and sensitivity. Here we report an advancement of the spatial filtering method, which combines the eigenspace projection of the measured data and the L1-norm minimization of the spatial filters' output noise amplitude, to further improve the detection power of BOLD contrast fMRI data. Using numerical simulation and in vivo data, we demonstrate that this eigenspace linearly constrained minimum amplitude (eLCMA) beamformer can reconstruct spatiotemporal hemodynamic signals with high statistical significance values and high spatial resolution in event-related two-choice reaction time visuomotor experiments.
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http://dx.doi.org/10.1016/j.neuroimage.2010.11.072DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3031661PMC
March 2011

Spatially sparse source cluster modeling by compressive neuromagnetic tomography.

Neuroimage 2010 Oct 19;53(1):146-60. Epub 2010 May 19.

Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.

Magnetoencephalography enables non-invasive detection of weak cerebral magnetic fields by utilizing super-conducting quantum interference devices (SQUIDs). Solving the MEG inverse problem requires reconstructing the locations and orientations of the underlying neuronal current sources based on the extracranial measurements. Most inverse problem solvers explicitly favor either spatially more focal or diffuse current source patterns. Naturally, in a situation where both focal and spatially extended sources are present, such reconstruction methods may yield inaccurate estimates. To address this problem, we propose a novel ComprEssive Neuromagnetic Tomography (CENT) method based on the assumption that the current sources are compressible. The compressibility is quantified by the joint sparsity of the source representation in the standard source space and in a transformed domain. The purpose of the transformation sparsity constraint is to incorporate local spatial structure adaptively by exploiting the natural redundancy of the source configurations in the transform domain. By combining these complementary constraints of standard and transformed domain sparsity we obtain source estimates, which are not only locally smooth and regular but also form globally separable clusters. In this work, we use the l(1)-norm as a measure of sparsity and convex optimization to yield compressive estimates in a computationally tractable manner. We study the Laplacian matrix (CENT(L)) and spherical wavelets (CENT(W)) as alternatives for the transformation in the compression constraint. In addition to the two prior constraints on the sources, we control the discrepancy between the modeled and measured data by restricting the power of residual error below a specified value. The results show that both CENT(L) and CENT(W) are capable of producing robust spatially regular source estimates with high computational efficiency. For simulated sources of focal, diffuse, or combined types, the CENT method shows better accuracy on estimating the source locations and spatial extents than the minimum l(1)-norm or minimum l(2)-norm constrained inverse solutions. Different transformations yield different benefits: By utilizing CENT with the Laplacian matrix it is possible to suppress physiologically atypical activations extending across two opposite banks of a deep sulcus. With the spherical wavelet transform CENT can improve the detection of two nearby yet not directly connected sources. As demonstrated by simulations, CENT is capable of reflecting the spatial extent for both focal and spatially extended current sources. The analysis of in vivo MEG data by CENT produces less physiologically inconsistent "clutter" current sources in somatosensory and auditory MEG measurements. Overall, the CENT method is demonstrated to be a promising tool for adaptive modeling of distributed neuronal currents associated with cognitive tasks.
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http://dx.doi.org/10.1016/j.neuroimage.2010.05.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2914202PMC
October 2010

Characterization of genomic structures and expression profiles of three tandem repeats of a mouse double homeobox gene: Duxbl.

Dev Dyn 2010 Mar;239(3):927-40

Department of Neurology, Chang-Hua Christian Hospital, and Department of Bioindustry Technology, Da-Yeh University, Dacun, Changhua, Taiwan.

We identified and cloned a mouse double homeobox gene (Duxbl), which encodes two homeodomains. Duxbl gene, a tandem triplicate produces two major transcripts, Duxbl and Duxbl-s. The amino acid sequences of Duxbl homeodomains are most similar to those of human DUX4 protein, associated with facioscapulohumeral muscular dystrophy. In adult tissues, Duxbl is predominantly expressed in female reproductive organs and eyes, and slightly expressed in brain and testes. During gonad development, Duxbl is expressed from embryonic to adult stages and specifically expressed in oocytes and spermatogonia. During embryonic development, Duxbl is transcribed in limbs and tail. However, Duxbl proteins were only detected in trunk and limb muscles and in elongated myocytes and myotubes. In C2C12 muscle cell line, Duxbl expression pattern is similar to differentiated marker gene, Myogenin, increased in expression from 2 days onward in differentiating medium. We suggest that Duxbl proteins play regulatory roles during myogenesis and reproductive developments.
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http://dx.doi.org/10.1002/dvdy.22210DOI Listing
March 2010

K-space reconstruction of magnetic resonance inverse imaging (K-InI) of human visuomotor systems.

Neuroimage 2010 Feb 13;49(4):3086-98. Epub 2009 Nov 13.

Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.

Using simultaneous measurements from multiple channels of a radio-frequency coil array, magnetic resonance inverse imaging (InI) can achieve ultra-fast dynamic functional imaging of the human with whole-brain coverage and a good spatial resolution. Mathematically, the InI reconstruction is a generalization of parallel MRI (pMRI), which includes image space and k-space reconstructions. Because of the auto-calibration technique, the pMRI k-space reconstruction offers more robust and adaptive reconstructions compared to the image space algorithm. Here we present the k-space InI (K-InI) reconstructions to reconstruct the highly accelerated BOLD-contrast fMRI data of the human brain to achieve 100 ms temporal resolution. Simulations show that K-InI reconstructions can offer 3D image reconstructions at each time frame with reasonable spatial resolution, which cannot be obtained using the previously proposed image space minimum-norm estimates (MNE) or linear constraint minimum variance (LCMV) spatial filtering reconstructions. The InI reconstructions of in vivo BOLD-contrast fMRI data during a visuomotor task show that K-InI offer 3 to 5 fold more sensitive detection of the brain activation than MNE and a comparable detection sensitivity to the LCMV reconstructions. The group average of the high temporal resolution K-InI reconstructions of the hemodynamic response also shows a relative onset timing difference between the visual (first) and somatomotor (second) cortices by 400 ms (600 ms time-to-peak timing difference). This robust and sensitive K-InI reconstruction can be applied to dynamic MRI acquisitions using a large-n coil array to improve the spatiotemporal resolution.
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http://dx.doi.org/10.1016/j.neuroimage.2009.11.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3745282PMC
February 2010