基于弥散张量成像的脑白质微结构分析方法在视路损伤中的应用进展

视觉通路包括视神经、视交叉、视束、视放射及视皮质。常规磁共振检查技术难以发现视路损伤后白质纤维微结构改变,眼科学检查也存在一定的局限性及主观性,且不能探测后视路的变化。弥散张量成像(diffusion tensor imaging,DTI)作为一种新兴的磁共振成像技术,通过各种后处理分析方法结合不同的参数进行分析,可提供组织的微结构信息,并能够直观显示活体白质纤维束,在无创地探索疾病的神经病理机制、评估预后方面起着重要的作用。近年来随着DTI后处理方法的不断创新,其在视路损伤中的研究越来越多。本文在介绍DTI的主要参数及常见脑白质微结构分析方法的同时,阐述了其在视路损伤研究中的应用,并进一步对各种分析方法的优缺点进行总结。     

Fine particulate matter and incidence of metabolic syndrome in non-CVD patients: A nationwide population-based cohort study

Background

It has been reported that particulate matter (PM) is associated with cardiovascular diseases (CVD) while metabolic syndrome is also an important risk factor for CVD. However, few studies have investigated the epidemiological association between PM and metabolic syndrome.

The Relationship Between Air Pollution and Lung Cancer in Nonsmokers in Taiwan

Introduction

For never-smokers (smoked <100 lifetime cigarettes), lung cancer (LC) has emerged as an important issue. We aimed to investigate the effects of prevalence changes in tobacco smoking and particulate matter (PM) 2.5 (PM_2.5) levels on LC in Taiwan, in relation to contrasting PM_2.5 levels, between Northern Taiwan (NT) and Southern Taiwan (ST).

利用Tox21通路数据库评估石家庄市大气细颗粒物中多环芳烃激活毒性通路的风险

目的： 采用Tox21毒性检测数据库中通路数据对2017年石家庄市供暖期大气细颗粒物（PM_2.5）中多环芳烃（PAHs）的检测数据进行分析计算，评估PM_2.5引起毒性通路激活的风险。方法： 在石家庄市河北医科大学远离工业污染源设置1个采样点收集大气PM_2.5，通过气相色谱-串联质谱法（GC-MS）检测美国环境保护署优先控制的16种PAHs的浓度。利用MPPD软件计算各PAHs单体在成人肺泡中的沉积量；检索Tox21毒性检测数据库中芳烃受体（AhR）、核因子E2相关因子（Nrf2）、p53和核因子κB（NF-κB）各通路的剂量反应关系数据，计算各PAHs单体激活各通路的单位强度；结合PAHs在肺泡的沉积量和PAHs激活通路的强度，评估PM_2.5激活各个通路的风险。结果： 石家庄市供暖期PM_2.5中PAHs检测结果显示，苯并[a]芘的日均浓度为9.13 ng/m³，日均浓度排名前3的苯并[b]荧蒽、荧蒽和芘的浓度分别为22.88、17.86及14.31 ng/m³。这16种PAHs以苯并[a]芘为参照的毒性当量浓度为17.74 ng/m³。毒性通路激活风险预测结果提示激活强度最大的是NF-κB通路，其次是AhR、Nrf2，p53被激活的可能性最弱，其中相对应的活性暴露比（AER）值分别为1.97、1.71、0.58和0.28。结论： 石家庄市大气细颗粒物中PAHs的暴露，可能通过激活NF-κB和AhR信号通路增加致癌风险。     

Effects of ambient particulate matter on vascular tissue: a review

ABSTRACT

Fine and ultra-fine particulate matter (PM) are major constituents of urban air pollution and recognized risk factors for cardiovascular diseases. This review examined the effects of PM exposure on vascular tissue. Specific mechanisms by which PM affects the vasculature include inflammation, oxidative stress, actions on vascular tone and vasomotor responses, as well as atherosclerotic plaque formation. Further, there appears to be a greater PM exposure effect on susceptible individuals with pre-existing cardiovascular conditions.     

Parenchymal calcification is associated with the neurological prognosis in patients with congenital rubella syndrome

Congenital rubella syndrome (CRS) results from maternal rubella virus infection in early pregnancy. Abnormal neuroimaging findings have been analyzed in a small number of CRS patients in the past; however, their clinical significance has been poorly addressed. Therefore, we have investigated the neuroimaging findings of 31 patients with CRS from previous studies. The most common finding was parenchymal calcification, which was observed in 18 of 31 patients (58.1%). A multivariable logistic regression model showed that it was associated with psychomotor or mental retardation (p = 0.018), suggesting that parenchymal calcification in CRS could be a prognostic factor.     

White matter alterations in Parkinson's disease with levodopa-induced dyskinesia

IntroductionLevodopa-induced dyskinesia is a complication of levodopa therapy and negatively impacts the quality of life of patients. We aimed to elucidate white matter alterations in Parkinson's disease with levodopa-induced dyskinesia using advanced diffusion magnetic resonance imaging techniques.MethodsThe enrolled subjects included 26 clinically confirmed Parkinson's disease patients without levodopa-induced dyskinesia, 25 Parkinson's disease patients with levodopa-induced dyskinesia, and 23 healthy controls. Subjects were imaged using a 3-T magnetic resonance scanner. Diffusion tensor imaging, diffusion kurtosis imaging, and neurite orientation dispersion and density imaging findings were compared between groups with a group-wise whole brain approach and a region-of-interest analysis for each white matter tract. Additionally, logistic regression analysis was used to calculate odds ratios for levodopa-induced dyskinesia.ResultsGroup-wise tract-based spatial statistical analysis revealed significant white matter differences in isotropic diffusion, complexity, or heterogeneity, and neurite density between healthy controls and Parkinson's disease patients without levodopa-induced dyskinesia and between patients with and without levodopa-induced dyskinesia. Region-of-interest analysis revealed similar alterations using a group-wise whole-brain approach in the external capsule, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, and uncinate fasciculus. These tracts had an odds ratio of approximately 2.3 for the presence of levodopa-induced dyskinesia.ConclusionsOur findings suggest that Parkinson's disease with levodopa-induced dyskinesia produces less white matter microstructural disruption, especially in temporal lobe fibers, than Parkinson's disease without levodopa-induced dyskinesia. These fibers has a more than 2-fold odds ratio for the presence of levodopa-induced dyskinesia and might be associated with the pathogenesis of the sequela.     

White matter hyperintensities affect transcranial electrical stimulation in the aging brain

BackgroundWhite matter hyperintensities (WMH) are estimated to occur in greater than 63% of older adults over the age of 60 years. WMH identified in the T2-weighted FLAIR images can be combined with T1-weighted images to enhance individualized current flow models of older adults by accounting for the presence of WMH and its effects on delivered tES current in the aging brain.MethodsIndividualized head models were derived from T1-weighted images of 130 healthy older adults (mean = 71 years). Lesions segmented from FLAIR acquisition were added to individualized models. Current densities were computed in the brain and compared between models with and without lesions.Main resultsIntegrating WMH into the models resulted in an overall decrease (up to 7%) in median current densities in the brain outside lesion regions. Changes in current density and total lesion volume was positively correlated (R² = 0.31, p < 0.0001).ConclusionsIncorporating WMH into individualized models may increase the accuracy of predicted tES current flow in the aging brain.     

Development of white matter microstructure and executive functions during childhood and adolescence: a review of diffusion MRI studies

Diffusion magnetic resonance imaging (dMRI) provides indirect measures of white matter microstructure that can be used to make inferences about structural connectivity within the brain. Over the last decade, a growing literature of cross-sectional and longitudinal studies have documented relationships between dMRI indices and cognitive development. In this review, we provide a brief overview of dMRI methods and how they can be used to study white matter and connectivity and review the extant literature examining the links between dMRI indices and executive functions during development. We explore the links between white matter microstructure and specific executive functions: inhibition, working memory and cognitive shifting, as well as performance on complex executive function tasks. Concordance in findings across studies are highlighted, and potential explanations for discrepancies between results, together with challenges with using dMRI in child and adolescent populations, are discussed. Finally, we explore future directions that are necessary to better understand the links between child and adolescent development of structural connectivity of the brain and executive functions.