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。     

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.     

空气细颗粒物暴露水平与健康成人大脑灰质体积和认知功能的关联研究

目的:应用磁共振成像(MRI)技术探究空气细颗粒物PM2.5暴露水平对健康成年人大脑灰质体积(GMV)和认知功能的影响。方法:选取487例健康成人,采集一般人口学信息及详细居住信息,并根据居住信息获取各受试近6个月和8岁～15岁期间的PM2.5暴露水平,对所有研究对象完成高分辨率结构MRI扫描,使用中文版精神分裂症认知功能成套测验-共识版(MCCB)进行认知测查,使用相关和回归分析探索空气PM2.5暴露水平与GMV和认知功能的关联。结果:近6个月PM2.5暴露水平与大脑右侧额下回三角部(brodmann分区[BA] 45)和右侧颞中回(BA 22)GMV存在负性关联(FWE校正,P<0.05,团块>10体素);与MCCB认知评估的信息处理速度-连线测试(r=-0.17,P<0.01)和推理和问题解决-迷宫测验评分(r=-0.22,P<0.01)负相关。8～15岁时的累积空气PM2.5暴露量与左侧梭状回(BA 18)和右侧舌回(BA 17)GMV负相关(FWE校正,P<0.05,团块>10体素),且与信息处理速度-连线测试、推理和问题解决-迷宫测验评分...     

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.     

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).

The need for new control strategies for particulate matter in parenterals

An undesirable characteristic in lyophilized parenteral products is the potential presence of particulate matter in the final product, which may affect patient safety. In this study, quality risk management tools described in the International Conference on Harmonization Guideline Q9 were used to estimate the risks for a pharmaceutical manufacturing line, based on three critical quality attributes: (1) visible particulate matter; (2) lyo-cake collapse traces; and (3) lyo-cake melt-back traces. Together with a Process Failure Mode Effect Analysis (PFMEA), an input-output analysis of the individual unit operations identified seven major material classes of extrinsic particulate matter. In addition to the process assessment, an experimental investigation of the location of impurities in lyophilized products was performed. To that end, intentionally contaminated vials were examined to locate the particulate matter and its possible migration. The results emphasize the importance of a full transmission mode release testing since the particles may enter the interior of the lyo-cake. A theoretical explanation of the observed impurity locations is provided.     

不同药用辅料流化床制粒的物性质量分析研究

目的研究5种药用辅料制粒后颗粒的物性指标,分析探讨颗粒物性指标的相关性及颗粒物性质量。方法采用Pearson相关性分析法分析颗粒的7项评价指标相关性,采用主成分分析法对颗粒物性指标进行主成分分析和综合评价。结果粒径分布宽度与松密度及振实密度呈极显著正相关,松密度与振实密度呈极显著正相关,振实密度与压缩度呈显著正相关。对第一主成分产生正向影响较大的物性指标是粒径分布宽度和振实密度。乳糖+水制成的颗粒及甘露醇+水制成的颗粒综合评价得分较高,可溶性淀粉+HPMC制成的颗粒综合评价得分最低。结论不同药用辅料制成的颗粒物性质量存在差异,乳糖和甘露醇分别以水为粘合剂制成的颗粒物性质量较好,可溶性淀粉以HPMC为粘合剂制成的颗粒物性质量较差。     

Demyelinating processes in aging and stroke in the central nervous system and the prospect of treatment strategy

Demyelination occurs in response to brain injury and is observed in many neurodegenerative diseases. Myelin is synthesized from oligodendrocytes in the central nervous system, and oligodendrocyte death‐induced demyelination is one of the mechanisms involved in white matter damage after stroke and neurodegeneration. Oligodendrocyte precursor cells (OPCs) exist in the brain of normal adults, and their differentiation into mature oligodendrocytes play a central role in remyelination. Although the differentiation and maturity of OPCs drive endogenous efforts for remyelination, the failure of axons to remyelinate is still the biggest obstacle to brain repair after injury or diseases. In recent years, studies have made attempts to promote remyelination after brain injury and disease, but its cellular or molecular mechanism is not yet fully understood. In this review, we discuss recent studies examining the demyelination process and potential therapeutic strategies for remyelination in aging and stroke. Based on our current understanding of the cellular and molecular mechanisms underlying remyelination, we hypothesize that myelin and oligodendrocytes are viable therapeutic targets to mitigate brain injury and to treat demyelinating‐related neurodegeneration diseases.     

Partial‐volume modeling reveals reduced gray matter in specific thalamic nuclei early in the time course of psychosis and chronic schizophrenia

The structural complexity of the thalamus, due to its mixed composition of gray and white matter, make it challenging to disjoint and quantify each tissue contribution to the thalamic anatomy. This work promotes the use of partial‐volume‐based over probabilistic‐based tissue segmentation approaches to better capture thalamic gray matter differences between patients at different stages of psychosis (early and chronic) and healthy controls. The study was performed on a cohort of 23 patients with schizophrenia, 41 with early psychosis and 69 age and sex‐matched healthy subjects. Six tissue segmentation approaches were employed to obtain the gray matter concentration/probability images. The statistical tests were applied at three different anatomical scales: whole thalamus, thalamic subregions and voxel‐wise. The results suggest that the partial volume model estimation of gray matter is more sensitive to detect atrophies within the thalamus of patients with psychosis. However all the methods detected gray matter deficit in the pulvinar, particularly in early stages of psychosis. This study demonstrates also that the gray matter decrease varies nonlinearly with age and between nuclei. While a gray matter loss was found in the pulvinar of patients in both stages of psychosis, reduced gray matter in the mediodorsal was only observed in early psychosis subjects. Finally, our analyses point to alterations in a sub‐region comprising the lateral posterior and ventral posterior nuclei. The obtained results reinforce the hypothesis that thalamic gray matter assessment is more reliable when the tissues segmentation method takes into account the partial volume effect.     

Medical masks’ and respirators’ pattern of use,adverse effects and errors among Portuguese health care professionals during the COVID-19 pandemic: A cross-sectional study

BackgroundDuring COVID-19 pandemic, a shortage of surgical masks (Mask) and respirators (Resp) was experienced worldwide. We aimed to assess its pattern of use, adverse effects and user errors by Portuguese health care professionals (HCP).MethodsA cross-sectional study was conducted through snowball convenience sample, collected by email/ social media to health care organizations. Participants answered an online anonymous survey in March 2021.ResultsMean age of 3052 respondents was 42.1 years old, 83.6% were female and 77.8% provided direct health care to COVID-19 patients. Mean time of use per shift was 6-8 hours in 40.8% of the participants. 28.0% reported never changing it during their shift. Resp use (vs Mask) was more associated with discomfort (58.2% vs 26.8%), affecting task performance (41.5 vs 18.9%) and communication (55.0 vs 40.9%), dyspnea (36.0 vs 14.4%), skin rash (37.5 vs 19.4%) and headache (37.5 vs 19.4%). Frequent user errors included touching the front while in use (70.1% Mask vs 66.3% Resp) and omitting hand hygiene before (61.8% Mask vs 55.0% Resp) or after use (61.3% Mask vs 57.0% Resp). Average number of errors was higher for Mask (4.3), than for Resp (3.2) (all: P < .001).ConclusionsMost HCP admitted an extended use of Mask/ Resp. Resp were more prone to adverse effects and Mask more prone to errors. Strategies to reinforce good practices should be considered.