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1.
J Neurol Sci ; 405: 116438, 2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31484082

RESUMO

OBJECTIVES: To assess microstructural alterations in white matter (WM) in amyotrophic lateral sclerosis (ALS) using diffusion tensor imaging (DTI). METHODS: DTI data were collected from 34 subjects (18 patients with ALS and 16 healthy controls). The atlas-based region of interest (ROI) analysis was conducted to assess WM microstructure in ALS by combining intra-voxel metrics, which included fractional anisotropy (FA) and mean diffusivity (MD), and an inter-voxel metric, i.e., local diffusion homogeneity (LDH). Correlation analysis of diffusion values and clinical factors was also performed. RESULTS: ALS group showed a significant FA reduction in bilateral corticospinal tract (CST) as well as right uncinate fasciculus (RUF). The areas with higher MD were situated in right corticospinal tract (RCST), left cingulum hippocampus (LCH), RUF, and right superior longitudinal fasciculus (RSLF). Additionally, ALS patients showed decreased LDH in bilateral anterior thalamic radiation (ATR), bilateral CST and left inferior frontal-occipital fasciculus (LIFOF). Significant correlations were observed between ALSFRS-R (revised ALS Functional Rating Scale) scores or progression rate and FA in bilateral CST, as well as between disease duration and LDH in right CST. Receiver operating characteristic (ROC) analysis revealed the feasibility of employing diffusion metrics along the CST to distinguish two groups (AUC = 0.792-0.868, p < .005 for all). CONCLUSIONS: WM microstructural alteration is a common pathology in ALS, which can be detected by both intra- and inter-voxel diffusion metrics. The extent of abnormalities in several WM tracts such as ATR and LIFOF may be better assessed through the inter-voxel diffusion measurement.

2.
Metab Brain Dis ; 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31363985

RESUMO

The hippocampus is a crucial pathological node for minimal hepatic encephalopathy (MHE) and it is associated with various cognitive impairments. Investigations on alterations involving hippocampal morphology and functional connectivity (FC) in MHE are limited. This study aimed to simultaneously evaluate hippocampal volume and FC alterations and their association with cognitive decline in MHE. Twenty-two cirrhotic patients with MHE, 31 cirrhotic patients without MHE (NHE), and 43 healthy controls underwent high-resolution T1-weighted imaging, resting-state functional magnetic resonance imaging, and cognition assessment based on Psychometric Hepatic Encephalopathy Score (PHES). The structural images were preprocessed using a voxel-based morphometry method, during which hippocampal volume was measured. The hippocampal connectivity network was identified using seed-based correlation analysis. Hippocampal volume and FC strength were compared across the three groups and correlated against the PHES results of the cirrhotic patients. Compared to the controls, MHE patients exhibited a significantly lower bilateral hippocampal volume. A slight decrease in hippocampal volume was obtained from NHE to MHE, but it did not reach statistically significance. In addition, the average FC strength of the bilateral hippocampal connectivity network was significantly lower in the MHE patients. In particular, the MHE patients showed a decrease in FC involving the left hippocampus to bilateral posterior cingulate gyrus and left angular gyrus. The MHE patients also showed FC reduction between the right hippocampus and bilateral medial frontal cortex. A progressive reduction in hippocampal FC from NHE to MHE was also observed. The bilateral hippocampal FC strength (but not hippocampal volume) was positively correlated with the PHES results of the cirrhotic patients. Our assessment of MHE patients revealed decreased hippocampal volume, which suggests regional atrophy, and reduced hippocampal connectivity with regions that are primarily involved in the default-mode network, thereby suggesting a functional disconnection syndrome. These alterations reveal the mechanisms underlying cognitive deterioration with disease progression.

3.
J Magn Reson Imaging ; 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31206873

RESUMO

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease in which cerebral structural impairment is a consistent feature. PURPOSE: To investigate cerebral microstructural changes in ALS using diffusion kurtosis imaging (DKI) for the first time. STUDY TYPE: Prospective. SUBJECTS: Eighteen ALS patients and 20 healthy controls. FIELD STRENGTH/SEQUENCE: DKI images were obtained by a spin-echo echo-planar imaging sequence on a 3T MRI scanner, with three b-values (0, 1000, and 2000 s/mm2 ) and 64 diffusion encoding directions. ASSESSMENT: The revised ALS Functional Rating Scale (ALSFRS-R) was administered to assess disease severity, and the symptom duration and disease progression rate were also recorded. Voxel-based analysis was applied to examine the alteration of DKI metrics (ie, mean kurtosis metrics [MK], axial kurtosis [AK], and radial kurtosis [RK]) and the conventional diffusion metrics (ie, fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity). STATISTICAL TESTS: Student's t-test, chi-square test, and Pearson correlation analysis. RESULTS: ALS patients showed MK reductions in gray matter areas, including the bilateral precentral gyrus, bilateral paracentral lobule, and left anterior cingulate gyrus; they also showed decreased MK values in white matter (WM) in the bilateral precentral gyrus, bilateral corona radiata, bilateral middle corpus callosum, left occipital lobe, and right superior parietal lobule. The spatial distribution of the regions with reduced RK was similar to those with decreased MK. No significant AK difference was found between groups. The correlation analysis revealed significant associations between DKI metrics and clinical assessments such as ALSFRS-R score and disease duration. Additionally, several WM regions showed between-group differences in conventional diffusion metrics; but the spatial extent was smaller than that with reduced DKI metrics. DATA CONCLUSION: The reduction in DKI metrics indicates decreased microstructural complexity in ALS, involving both motor-related areas and extramotor regions. DKI metrics can serve as potential biomarkers for assessing disease severity. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019.

4.
Appl Opt ; 58(10): 2463-2470, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31045038

RESUMO

We theoretically investigate the optical bistability in a composite photonic molecule cavity optomechanical system consisting of two whispering gallery mode microcavities, where one of the optical cavities is optomechanical with a high quality factor, and the other optical cavity is an auxiliary cavity with high cavity dissipation. By controlling the coupling strength J between the two cavities determined by their distance, the decay rate ratio δ of the two cavities, and the pump power P, the optical bistability can be controlled. Further, the transmission spectrum of the signal field can be efficiently attenuated or amplified, depending on the power of a second "gating" (pump) field P, and other parameters. Our study for photonic-molecule optomechanics systems may be a promising candidate for single-photon transistors and pave the way for potential applications in quantum information technologies.

5.
Lung Cancer ; 131: 134-138, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31027690

RESUMO

OBJECTIVES: Leptomeningeal metastases (LM) had increased in advanced non-small-cell lung cancer (NSCLC) over the last 10 years. The survival outcome remained overall poor, heterogeneous and was reported in association with genotypes in lung cancer patients with LM. Graded prognostic assessment model integrated with molecular alterations (molGPA) might be accurate for outcome prediction of LM patients, but needs to be established. MATERIALS AND METHODS: We retrospectively screened 8921 consecutive lung cancer patients from January 2011 to March 2018. A total of 301 patients diagnosed as LM were enrolled, and randomly divided into training and validation sets after stratified by gender and age. A molGPA score for each patient was calculated based on the weighted significant parameters including gene mutations. RESULT: The median OS for the 301 patients was 9.2 months (95%CI: 7.9-10.5). In the training set, EGFR/ALK positivity, Karnofsky performance score (KPS) score≥60 and absence of extracranial metastasis (ECM) independently predicted better OS. We developed a molGPA model based on above significant prognostic factors. This molGPA model classified LM patients into three prognosis groups of high, intermediate and low risk (molGPA score of 0, 0.5-1.0 and 1.5-2.0, respectively. The median OS of high, intermediate and low risk LM patients in the training set was 0.3, 3.5 and 15.9 months, respectively (p < 0.001). In the validation set, the median OS was 0.9, 5.8 and 17.7 months in the three molGPA subgroups, accordingly (p < 0.001). The C-index of this model in training and validation sets was 0.70 (95%CI: 0.66-0.73) and 0.64 (95%CI: 0.58-0.70) respectively. CONCLUSION: The LM molGPA model with integration of gene status, KPS and ECM can accurately classify lung cancer patients with LM into diverse prognosis.

6.
Eur J Cancer ; 109: 183-191, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30739019

RESUMO

BACKGROUND: Nab-paclitaxel/carboplatin (nab-PC) and gemcitabine/carboplatin (GC) are the standard first-line chemotherapy in non-small cell lung carcinoma. Up to now, there is no head to head trial to compare nab-PC with GC in advanced squamous cell lung carcinoma. PATIENTS AND METHODS: A multicentre randomised phase II trial was performed to compare the efficacy and safety for nab-PC with GC in previously untreated patients with advanced squamous cell lung carcinoma. The primary end-point was objective response rate (ORR). Progression-free survival (PFS), overall survival (OS), treatment-related adverse events and quality of life (QoL) were also analysed. RESULTS: Totally 127 participants were eligible for this study (62/65 nab-PC/GC). Nab-PC has higher ORR than GC without statistical significance (42% versus 27%, P > 0.05). After a median follow-up of 14.5 months, both PFS and OS had no difference between the two arms (6.7 versus 5.8 months, hazard ratio [HR] 0.75, P = 0.143; 11.6 versus 14.4 months, HR 0.92, P = 0.846). Both regimens were well tolerated; however, more dose reduction occurred after cycle 2 in GC (27%) than in nab-PC (12%) (P < 0.05). Significant QoL improvement measured by trial outcome index was seen in nab-PC than in GC (P < 0.05). CONCLUSIONS: The first-line nab-PC and GC had the same response, PFS, and OS in patients with advanced squamous cell lung carcinoma. Nab-PCM has advantage over GC in QoL improvement. TRIAL REGISTRATION NUMBER: NCT01236716.

7.
J Thorac Oncol ; 14(5): 924-932, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30659989

RESUMO

INTRODUCTION: Leptomeningeal metastases (LMs) indicated a poor prognosis in NSCLC. LMs were more frequent in driver gene-mutated patients, and cerebrospinal fluid (CSF) cell-free DNA has shown unique genetic profiles of LM in EGFR-mutated LM. However, studies in patients with ALK receptor tyrosine kinase gene (ALK)-rearranged NSCLC with LMs are scarce. METHODS: Patients with lung cancer with ALK rearrangement were screened from September 2011 to February 2018 at our institute. CSF and paired plasma were tested by next-generation sequencing. RESULTS: LMs were diagnosed in 30 (10.3%) of 291 patients with ALK-rearranged lung cancer. A total of 11 paired CSF and plasma samples tested by next-generation sequencing were analyzed. Driver genes were detected in 81.8% of the CSF samples (9 of 11) and 45.5% of the plasma samples (5 of 11) (p = 0.183). The maximum allelic fractions were all higher in CSF than in plasma (p = 0.009). ALK and tumor protein p53 gene (TP53) were the two most frequently mutated genes in CSF. Gatekeeper gene ALK G1202R and C1156F mutations were identified in CSF after resistance to alectinib. Multiple copy number variants were mainly found in CSF, including in EGFR, cyclin D1 gene (CCND1), fibroblast growth factor 3 gene (FGF3), and fibroblast growth factor 4 gene (FGF4). Also found were v-myc avian myelocytomatosis viral oncogene homolog gene (MYC) copy number gains and TP53 and cyclin dependent kinase inhibitor 2A gene (CDKN2A) copy number deletions. Brigatinib seemed to be effective in controlling LM. One case showed that CSF could be used to monitor disease development of LM and longitudinally monitor tumor response. CONCLUSION: Liquid biopsy of CSF is more sensitive than liquid biopsy of plasma to detect targetable alterations, characterizing resistance mechanisms on progression and monitoring tumor response in patients with ALK-rearranged NSCLC with LM. Thus, CSF might be promising as a medium of liquid biopsy in LM.

8.
Sci Rep ; 8(1): 17677, 2018 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-30518767

RESUMO

Majorana fermions (MFs), due to their significance in fundamental physics and potential applications in topological quantum computation based on solid-state devices, have drawn widespread attention. Here, we design a hybrid semiconductor/superconductor ring (S/SR) device and put forward an optical method for detecting a pair of MFs in the S/SR device with a quantum dot (QD) with the popular optical pump-probe scheme, which is very different from the present electrical method only considering one nearby MF coupled to the QD. The symmetric and unsymmetric Rabi splitting and optical Kerr nonlinear effect of QD mediated by MFs are investigated under uncoupled and coupled majorana modes, respectively. The coherent optical spectra indicate that a pair of MFs coupled to the QD induced remarkable splitting under different parameters regime and the physical origin of these phenomena are elaborated detailedly. Due to QD-MFs coupling, the probe absorption spectra present the phenomenon of Majorana modes induced transparency (MMIT) which will induce remarkable phenomena of slow light. The coherent optical spectra afford a potential supplement for probing MFs and support Majorana fermions-based topological quantum computation.

9.
BMC Cancer ; 18(1): 1171, 2018 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-30477470

RESUMO

OBJECTIVE: Crizotinib can target against mesenchymal-epithelial transition (MET) and anaplastic lymphoma kinase (ALK), which has been considered as a multi-targeted tyrosine kinase inhibitor (TKI). The objective of this study was to explore the efficacy of crizotinib in advanced non-small-cell lung cancer (NSCLC) with concomitant ALK rearrangement and c-Met overexpression. METHODS: Totally, 4622 advanced NSCLC patients from two institutes (3762 patients at the Guangdong Lung Cancer Institute from January 2011 to December 2016 and 860 cases at the Perking Cancer Hospital from January 2015 to December 2016) were screened for ALK rearrangement with any method of IHC, RACE-coupled PCR or FISH. C-Met expression was performed by IHC in ALK-rearranged patients, and more than 50% of cells with high staining were defined as c-Met overexpression. The efficacy of crizotinib was explored in the ALK-rearranged patients with or without c-Met overexpression. RESULTS: Sixteen patients were identified with c-Met overexpression in 160 ALK-rearranged cases, with the incidence of 10.0% (16/160). A total of 116 ALK-rearranged patients received the treatment of crizotinib. Objective response rate (ORR) was 86.7% (13/15) in ALK-rearranged patients with c-Met overexpression and 59.4% (60/101)in those without c-Met overexpression, P = 0.041. Median PFS showed a trend of superiority in c-Met overexpression group (15.2 versus 11.0 months, P = 0.263). Median overall survival (OS) showed a significant difference for ALK-rearranged patients with c-Met overexpression group of 33.5 months with the hazard ratio (HR) of 3.2. CONCLUSIONS: C-Met overexpression co-exists with ALK rearrangement in a small population of advanced NSCLC. There may be a trend of favorable efficacy of crizotinib in such co-altered patients.

10.
J Cancer ; 9(17): 2987-2993, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30210620

RESUMO

Clinical studies have confirmed epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) used in lung cancer patients with EGFR mutations can obtain a better result, but still part of the patients with poor efficacy. EGFR mutation is highly related to female, nonsmoking and adenocarcinoma. Thus, we hypothesize that estrogen and circulating HER-2/neu protein might influence the efficacy of EGFR-TKIs in EGFR mutant patients with non-small cell lung cancer. HER-2/neu expression level of 357 eligible patients in its peripheral serum was determined using ELISA. The median progression-free survival (PFS) in five groups (premenopausal group, perimenopause group, peri to postmenopausal group, postmenopausal group and control group) was statistically difference (P = 0.025). Premenopausal group could predict the efficacy of EGFR-TKI (HR = 2.45, 95% CI = 1.42-4.23, P = 0.001). No statistical significance was found in median overall survival (OS) among five groups. Optimal diagnostic cut off value of HER-2/neu was set at 47.5 ng/ml, with P = 0.0607. As the cutoff value to 47.5 ng/ml division, concentrations and menopausal status was of no significant difference (P = 0.874). PFS of the group below 47.5 ng/ml was significantly longer than that of the group over 47.5 ng/ml (P = 0.000). HER-2/neu concentration was positively correlated with optimal efficacy (P = 0.042). HER-2/neu concentration over than 47.5 ng/ml was a risk factor of EGFR-TKI prognosis. Premenopausal status is an independent predictor of EGFR-TKI curative effect and circulating HER-2/neu protein is an independent prognostic factor in patients with advanced NSCLC.

11.
Opt Express ; 26(16): 20076-20088, 2018 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-30119323

RESUMO

In this paper, we introduce a new kind of partially coherent vector beam with special correlation function and vortex phase named radially polarized Laguerre-Gaussian-correlated Schell-model (LGCSM) vortex beam as a natural extension of scalar LGCSM vortex beam. The realizability conditions for such beam are derived. The tight focusing properties of a radially polarized LGCSM vortex beam passing through a high numerical aperture (NA) objective lens are investigated numerically based on the vectorial diffraction theory. We find that not only the transverse component but also the longitudinal component of the focal field distributions can be shaped by regulating the structures of the correlation functions, which is quite different from that of the conventional radially polarized partially coherent beam. Moreover, a series of wildly used focal field with novel structure, e.g., focal spot, flat-topped or doughnut beam profiles, needle-like focal field and controllable three-dimensional (3D) optical cage, were obtained. These results indicate that the focus shaping can be achieved by combining the regulation of the structures of the correlation functions with the regulation of beam parameters effectively. Our results may be useful for potential applications in optical trapping, optical high-resolution microscopy and optical data storage.

12.
Front Neuroanat ; 12: 53, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29997482

RESUMO

Purpose: The aim of this study was to evaluate microstructural changes of major white matter (WM) tracts in patients with vascular cognitive impairment (VCI). Method: Diffusion tensor imaging (DTI) data were obtained from 24 subjects with subcortical ischemic vascular disease (SIVD), including 13 subjects with VCI-no dementia (VCIND) and 11 subjects with normal cognition (as a control group). A tract-based spatial statistics approach was performed to investigate WM microstructure in VCIND by integrating multiple indices including fractional anisotropy (FA) and mean diffusivity (MD), which are intra-voxel metrics, and local diffusion homogeneity (LDH), which is an inter-voxel metric. Results: The VCIND group had decreased FA and increased MD values throughout widespread WM areas predominately in the corpus callosum, bilateral internal capsule/corona radiata/posterior thalamic radiation/inferior fronto-occipital fasciculus and right inferior/superior longitudinal fasciculus. There was a slight discrepancy between the distribution of areas with decreased FA and LDH. The FA, MD and LDH values were significantly correlated with cognitive test results. According to a WM tract atlas, 10 major tracts were identified as tracts of interest in which three diffusion metrics simultaneously differed between groups, including bilateral anterior thalamic radiation, forceps minor, right corticospinal tract, bilateral inferior fronto-occipital fasciculus, left inferior and superior longitudinal fasciculus, and bilateral uncinate fasciculus. Receiver operating characteristic (ROC) analysis demonstrated the feasibility of using diffusion metrics along the forceps minor and left anterior thalamic radiation for separating two groups. Conclusion: The results suggest WM microstructural abnormalities contribute to cognitive impairments in SIVD patients. DTI parameters may be potential biomarkers for detecting VCIND from SIVD.

13.
Thorac Cancer ; 9(9): 1093-1103, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29978950

RESUMO

BACKGROUND: ALK-tyrosine kinase inhibitors (TKIs) have been proven effective for treating ALK-positive non-small cell lung cancer (NSCLC), although patients present with variable responses and disease progression courses. The detailed underlying molecular mechanisms require further investigation to yield a better prognosis. METHODS: Targeted next-generation sequencing (NGS) mutation profiling was performed on samples from 42 NSCLC patients confirmed positive for ALK rearrangements by fluorescence in situ hybridization or immunohistochemistry who experienced disease progression after crizotinib treatment. RESULTS: ALK rearrangements were not confirmed in six patients (14%) with other potential oncogenic drivers identified by NGS, who therefore did not respond to crizotinib and had significantly shorter overall survival (OS) compared to NGS ALK -positive patients. Fifteen ALK activating mutations were detected in 8 out of 26 post-treatment samples (31%), among which ALK L1196M and G1269A were the most common acquired mutations detected in half of the patients with ALK activating mutations. Dynamic monitoring of the genetic evolution in one patient revealed both spatial and temporal heterogeneity of resistant mechanisms during different ALK-TKI treatment courses. Activation of ALK downstream or bypass pathways was detected in patients without ALK activating mutations, such as genetic alterations in PIK3CA, MET, and KRAS. Interestingly, we identified two patients with acquired mutations in the DNA mismatch repair gene POLE, which resulted in a dramatically increased tumor mutation burden, and might contribute to the poor response to crizotinib. CONCLUSIONS: Heterogeneous resistant mechanisms have been identified and correlate to diverse responses to crizotinib. Comprehensive and dynamic mutation profiling is required to better predict clinical outcomes.

14.
Sci Rep ; 8(1): 8817, 2018 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-29892049

RESUMO

We demonstrate that directional electromagnetic scattering can be realized in an artificial Mie resonant structure that supports electric and magnetic dipole modes simultaneously. The directivity of the far-field radiation pattern can be switched by changing wavelength of the incident light as well as tailoring the geometric parameters of the structure. In addition, we further design a quasiperiodic spoof Mie resonant structure by alternately inserting two materials into the slits. The results show that multi-band directional light scattering is realized by exciting multiple electric and magnetic dipole modes with different frequencies in the quasiperiodic structure. The presented design concept is suitable for microwave to terahertz region and can be applied to various advanced optical devices, such as antenna, metamaterial and metasurface.

15.
Brain Imaging Behav ; 2018 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-29846883

RESUMO

A higher risk of cognitive impairments has been found after an overt hepatic encephalopathy (OHE) episode in cirrhotic patients. We investigated the effect of prior OHE episodes on the topological organization of the functional brain network and its association with the relevant cognitive impairments. Resting-state functional MRI data were acquired from 41 cirrhotic patients (19 with prior OHE (Prior-OHE) and 22 without (Non-Prior-OHE)) and 21 healthy controls (HC). A Psychometric Hepatic Encephalopathy Score (PHES) assessed cognition. The whole-brain functional network was constructed by thresholding functional correlation matrices of 90 brain regions (derived from the Automated Anatomic Labeling atlas). The topological properties of the brain network, including small-worldness, network efficiency, and nodal efficiency, were examined using graph theory-based analysis. Globally, the Prior-OHE group had a significantly decreased clustering coefficient and local efficiency, compared with the controls. Locally, the nodal efficiency in the bilateral medial superior frontal gyrus and the right postcentral gyrus decreased in the Prior-OHE group, while the nodal efficiency in the bilateral anterior cingulate/paracingulate gyri and right superior parietal gyrus increased in the Prior-OHE group. The alterations of global and regional network parameters progressed from Non-Prior-OHE to Prior-OHE and the clustering coefficient and local efficiency values were significantly correlated with PHES results. In conclusion, cirrhosis leads to the reduction of brain functional network efficiency, which could be aggravated by a prior OHE episode. Aberrant topological organization of the functional brain network may contribute to a higher risk of cognitive impairments in Prior-OHE patients.

16.
Front Neurol ; 9: 14, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29422882

RESUMO

Objective: Patients with cirrhosis often exhibit cognitive deficits, particularly executive dysfunction, which is considered a predictor of overt hepatic encephalopathy (OHE). We examined brain intrinsic networks associated with executive function to investigate the neural basis of this cognitive deficiency in cirrhosis. Methods: Resting-state functional MRI data were acquired from 20 cirrhotic patients and 18 healthy controls. Seed-based correlation analysis was used to identify the three well-known networks associated with executive function, including executive control (ECN), default mode (DMN), and salience (SN) networks. Functional connectivity (FC) within each network was compared between groups and correlated with patient executive performance (assessed by the Stroop task). Results: Patients showed decreased FC between the ECN seed (right dorsolateral prefrontal cortex) and several regions (including right middle/inferior frontal gyrus, left inferior frontal gyrus, bilateral inferior/superior parietal lobules, bilateral middle/inferior temporal gyrus, and right medial frontal gyrus), between the DMN seed [posterior cingulate cortex (PCC)] and several regions (including bilateral medial frontal gyrus, bilateral anterior cingulate cortex, bilateral superior frontal gyrus, bilateral precuneus/PCC, left supramarginal gyrus, and left middle temporal gyrus), and between the SN seed (right anterior insula) and right supramarginal gyrus. FC strength in the ECN and SN was negatively correlated with patient performance during the Stroop task. Conclusion: Disrupted functional integration in the core brain cognitive networks, which is reflected by reductions in FC, occurs before OHE bouts and may play an important role in the neural mechanism of executive dysfunction associated with cirrhosis.

18.
Eur Radiol ; 28(1): 85-95, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28667481

RESUMO

OBJECTIVES: To investigate structural brain connectome alterations in cirrhotic patients with prior overt hepatic encephalopathy (OHE). METHODS: Seventeen cirrhotic patients with prior OHE (prior-OHE), 18 cirrhotic patients without prior OHE (non-prior-OHE) and 18 healthy controls (HC) underwent diffusion tensor imaging. Neurocognitive functioning was assessed with Psychometric Hepatic Encephalopathy Score (PHES). Using a probabilistic fibre tracking approach, we depicted the whole-brain structural network as a connectivity matrix of 90 regions (derived from the Automated Anatomic Labeling atlas). Graph theory-based analyses were performed to analyse topological properties of the brain network. RESULTS: The analysis of variance showed significant group effects on several topological properties, including network strength, global efficiency and local efficiency. A progressive decrease trend for these metrics was found from non-prior-OHE to prior-OHE, compared with HC. Among the three groups, the regions with altered nodal efficiency were mainly distributed in the frontal and occipital cortices, paralimbic system and subcortical regions. The topological metrics, such as network strength and global efficiency, were correlated with PHES among cirrhotic patients. CONCLUSIONS: The cirrhotic patients developed structural brain connectome alterations; this is aggravated by prior OHE episode. Disrupted topological organization of the brain structural network may account for cognitive impairments related to prior OHE. KEY POINTS: • Altered structural brain connectome is found in cirrhotic patients. • Structural brain connectome alterations could be aggravated by prior-OHE episode. • Altered structural brain connectome may account for cognitive impairments associated with prior OHE.


Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Encefalopatia Hepática/complicações , Cirrose Hepática/complicações , Imagem por Ressonância Magnética/métodos , Mapeamento Encefálico/métodos , Feminino , Encefalopatia Hepática/fisiopatologia , Humanos , Cirrose Hepática/fisiopatologia , Masculino , Pessoa de Meia-Idade
19.
Opt Lett ; 42(21): 4521-4524, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-29088203

RESUMO

It has been recently shown that a solid-textured metal cylinder can support electric and magnetic dipolar resonances simultaneously [Phys. Rev. X4, 021003 (2014)PRXHAE2160-330810.1103/PhysRevX.4.021003] which are almost degenerate in a two-dimensional (2-D) structure and non-degenerate in a three-dimensional (3-D) structure, and with the magnetic dipole appearing at higher frequency. They are described as spoof localized plasmonic modes analogous to localized plasmonic resonances in optical frequencies. Here, we consider a hollow metal cylinder corrugated by periodic cut-through slits. Our results indicate that the magnetic dipole can be separated from the electric dipole in a 2-D structure, and magnetic dipolar resonance appears at lower frequency, rather than electric resonance in both 2-D and 3-D structures. In order to clarify the physical mechanism behind the abnormal phenomenon, we study the influence of the core material on the electric- and magnetic-dipole modes based on theoretical analysis and numerical simulation. It is discovered that there is a threshold of an imaginary part of permittivity for switching the order between electric and magnetic dipoles. These results may provide fundamental understanding and physical insight for spoof plasmonic modes supported in designer structures.

20.
Oncotarget ; 8(46): 81369-81376, 2017 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-29113396

RESUMO

Background: Bone metastasis and skeletal related events (SREs) are common in non-small cell lung cancer (NSCLC). Patients with mutant epidermal growth factor receptor (EGFR) could benefit from tyrosine kinase inhibitors (TKIs). However, it is unclear whether SRE is influenced by EGFR status. We aimed to evaluate the correlation of EGFR status and TKIs with the incidence of SREs. Methods: We conducted a retrospective study of stage IV NSCLC patients with bone metastasis. Incidence rate of SREs was collected and was compared using chi-square test. Logistic-regression analysis was used to identify the risk factors predicting the incidence of SREs. Results: 410 eligible patients were enrolled in the study. 49.0% were detected with EGFR mutation. 49.8% of patients received EGFR-TKIs therapy prior to the onset of SREs. 42.7% experienced at least one SRE. Patients who were treated with TKIs held lower incidence of SREs than patients who were not treated with TKIs (23.5% vs 61.7%, p<0.001). Multivariate analysis showed that poor performance status (OR 5.550, 95%CI 2.290-13.450; p<0.001) and mutant EGFR (OR 3.050, 95%CI 1.608-5.787, p=0.001) were independent risk factors predicting the onset of SREs, while the usage of TKIs (OR 0.102, 95%CI 0.054-0.193, p<0.001) was a protective factor of SREs in NSCLC patients with bone metastasis. Conclusions: This study indicates that the incidence of SREs is common in both patients with and without EGFR mutation. Poor performance ability and mutant EGFR imply higher risks of SREs, while the usage of TKIs may be a protective factor of SREs.

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