The hierarchical factor model of ADHD: invariant across age and national groupings?

Objective: To examine the factor structure of attention‐deficit/hyperactivity disorder (ADHD) in a clinical sample of 1,373 children and adolescents with ADHD and their 1,772 unselected siblings recruited from different countries across a large age range. Hierarchical and correlated factor analytic models were compared separately in the ADHD and sibling samples, across three different instruments and across parent and teacher informants. Specific consideration was given to factorial invariance analyses across different ages and different countries in the ADHD sample. Method: A sample of children and adolescents between 5 and 17 years of age with ADHD and their unselected siblings was assessed. Participants were recruited from seven European countries and Israel. ADHD symptom data came from a clinical interview with parents Parental Account of Childhood Symptoms and questionnaires from parents and teachers (Conners Parent and Teacher). Results: A hierarchical general factor model with two specific factors best represented the structure of ADHD in both the ADHD and unselected sibling groups, and across informants and instruments. The model was robust and invariant with regard to age differences in the ADHD sample. The model was not strongly invariant across different national groups in the ADHD sample, likely reflecting severity differences across the different centers and not any substantial difference in the clinical presentation of ADHD. Conclusions: The results replicate previous studies of a model with a unitary ADHD component and separable specific traits of inattention and hyperactivity/impulsivity. The unique contribution of this study was finding support for this model across a large developmental and multinational/multicultural sample and its invariance across ages.     

Experimental and theoretical analysis of cytokine release for the study of radiation-induced bystander effect

Purpose: To clarify the experimental conditions that might influence the release of cytokines in the culture medium and give some basic input for building a model for cytokine (e.g., Interleukin-6, IL-6) regulation in the case of ‘sham irradiation’ and after ionising radiation exposure.

Materials and methods: The influence of cell type, cell density, medium volume, medium storage temperature and other methodological aspects on IL-6 and Interleukin-8 (IL-8) release were investigated. In addition, the effects over the time of different doses of gamma irradiation on the clonogenic survival of bystander cells and on the secretion of these cytokines were studied.

Results: We observed significant decreases of clonogenic survival in AG01522 and T98G cells after the transfer of medium collected 5 and 20 h after low doses of gamma irradiation. Concerning the Interleukins' measurements, our experiments showed that the aggregate removal modalities tested, and up to 10 freeze-thaw cycles, do not have significant influence on the measurements of IL-6 concentration in the medium. We also observed that the IL-6 accumulated in the medium of human fibroblasts is not degraded when maintained at 37°C. Sets of experiments demonstrated that cell density or medium volume do not influence the release of IL-6. On the contrary, our results showed that IL-8 released by glioblastoma cells strongly depends on the amount of medium. Finally, the exposure of fibroblasts to gamma irradiation has influence on the release kinetics of both IL-6 and IL-8 with peculiar features.

Conclusions: This study solved some of the methodological doubts concerning the study of bystander effects by means of the medium transfer technique; moreover it also highlighted some experimental aspects that need to be considered when approaching this sort of experiments.     

Sourcing and using stem cell lines for radiation research: Potential,challenges and good stem cell culture practice

Abstract

Purpose: Exposition of best practice in management and experimental use of human stem cell lines in radiobiological research. This paper outlines the key challenges to be addressed by radiobiologists wishing to use human pluripotent stem cell (hPSC) lines in their research including human embryonic stem cell (hESC) lines and human induced pluirpotency stem (hiPSC) lines. It emphasises the importance of guidance already established for cell culture in general and outlines some further considerations specific to the culture of human pluripotent stem cell lines which may impact on the interpretation of data from radiobiological studies using these cells. Fundamental standards include obtaining cells from bona fide suppliers with suitable quality controls, screening cell lines to ensure absence of mycoplasma and authentication of cell lines by DNA profiling. For hESC and hiPSC lines, it is particularly important to recognise the significance of phenotypic and genetic stability and this paper will address approaches to reduce their impact. Quality assured banking of these two types of stem cell lines will facilitate reliable supply of quality controlled cells that can provide standardisation between laboratories and in the same laboratory over time.

Conclusions: hPSC lines could play an important role in future radiobiological research providing certain fundamental principles of good stem cell culture practice are adopted at the outset of such work.     

兔颅脑棍棒打击伤模型的建立及实验条件探讨

目的建立用于模拟法医棍棒打击致颅脑损伤的动物模型。方法在BIM-II型生物撞击机的基础上自行设计铁质棍棒,将24只新西兰大白兔分为对照组、轻伤组与重伤组,致伤后6h进行解剖,观察损伤形态,并取材做常规病理,行CT及脑组织含水量检查。结果致伤组均出现不同程度的神经系统阳性体征,6h内轻伤组死亡率1／10,重伤组6／10,形态学及CT改变主要表现为不同程度的头皮血肿、颅骨骨折、硬膜外血肿、硬膜下血肿、蛛网膜下腔出血及脑损伤。各组之间脑含水量差异有统计学意义。结论在严格控制实验参数的情况下,该动物模型重复性好,实验结果稳定,能够较好地模拟法医检案中铁棒损伤形态,可用于法医学中颅脑钝性损伤机制的实验研究。     

清醒与麻醉状态经典型热射病大鼠模型比较

目的 构建清醒状态经典型热射病(CHS)大鼠模型,与传统麻醉状态CHS大鼠模型进行比较,为研究自然状态下CHS的发病机制奠定基础.方法 雄性SPF级SD大鼠32只,随机分为高温清醒状态组(C-CHS)、高温麻醉状态左股动脉插管组(N-CHS)和相应的正常对照组(C-NC和N-NC组),每组8只.CHS组大鼠予39℃热打击,监测核心体温(Tr)和动脉收缩压(SBP)变化,比较Tr、SBP调节反应和生存时间的差异.结果 C-CHS和N-CHS组大鼠表现为不同的Tr和SBP调节特征.尽管最大Tr无显著差异,但是与C-CHS组大鼠比较,N-CHS组大鼠核心体温上升速率显著加快(P＜0.05),成模时间显著缩短(P＜0.05),总热负荷和重度热负荷均显著减少(P＜0.05),预后也更差(p＜0.05).结论 清醒状态CHS大鼠模型接近大鼠生理状态,更适合于实验性大鼠CHS的研究.对于清醒状态CHS大鼠模型的进一步研究,可以促进对CHS发病机制的理解.     

黑火药烟雾致吸入性肺损伤大鼠模型的建立与评价

目的 构建黑火药烟雾所致吸入性肺损伤大鼠模型并对其进行评价.方法 分析黑火药烟雾成分,建立吸入性肺损伤大鼠模型.42只健康雄性Wistar大鼠随机分为对照组和建模后1、2、6、24、48、96h组(n=6),检测各组大鼠动脉血气的变化,测定肺湿/干比(W/D)、支气管肺泡灌洗液(BALF)中白细胞数及蛋白含量,并取肺组织行大体及镜下病理组织学观察.结果 黑火药烟雾成分主要为CO2和CO,且12min内浓度稳定.大鼠吸入烟雾后表现为低氧血症,COHb于吸入后1h达峰值(P＜0.05),W/D于2h达峰值(P＜0.05),吸入后24h内BALF白细胞数呈进行性增加(P＜0.05),蛋白含量显著增高(P＜0.05).病理观察可见肺组织出血、水肿及炎性细胞浸润,呈急性肺损伤表现,至吸入后96h仍未恢复.结论 通过黑火药烟雾暴露可成功建立大鼠吸入性肺损伤模型,且具有易复制、稳定、可靠的优点,可用于战场环境下吸入性肺损伤的实验研究.     

辣椒和乙醇对肉桂醛引起的兔耳刺激性接触性皮炎的影响

目的 探讨辣椒和乙醇对肉桂醛引起的皮肤刺激性接触性皮炎的影响.方法 日本大耳白兔32只,随机分成对照组、乙醇组、辣椒组、混合组,每组8只.对照组:生理氯化钠溶液日2次灌胃;乙醇组:50％乙醇、生理氯化钠溶液分别灌胃;辣椒组:10％辣椒液、生理氯化钠溶液分别灌胃;混合组:50％乙醇、10％辣椒液分别灌胃.剂量均为每次8 ml/kg,各组连续灌注7d.出现饮水量增加、大便干结、耳廓血管充血等辛辣刺激体征后,再将各组实验动物分成完整皮肤组和破损皮肤组,每组4只,按化妆品卫生规范进行皮肤刺激性实验,分别记录1、24、48和72 h刺激部位的情况,对皮肤刺激反应进行评分,组间差异比较采用方差分析.结果 辣椒与乙醇连续7d灌胃后,对照组症状体征评分为0.25±0.46,辣椒组为5.38±0.74,乙醇组为7.25±0.71,混合组为12.75±0.70,辣椒组、乙醇组及混合组的症状体征评分明显高于对照组,差异有统计学意义(P＜0.01).在家兔完整皮肤刺激状态评分中,混合组皮肤刺激反应强度在24、48 h显著高于灌注辣椒组(F=28.44、30.33,P＜0.05);在家兔破损皮肤刺激状态评分中,乙醇组、混合组皮肤刺激反应强度在24、48、72 h评分显著高于辣椒组(F=197.12、94.54、87.63,P＜ 0.01).结论 按照实验所用的剂量,辣椒、乙醇和混合物都能够在家兔诱导出辛辣刺激体征,辣椒和乙醇能明显增加皮肤对肉桂醛刺激的敏感性.     

三维数字化模型测量牙齿和牙弓的精确性研究

目的 通过与手工测量法比较,评估三维数字化法模型测量牙齿和牙弓的可靠性和精确性。方法 选择喀什地区维吾尔族成年人石膏模型150副,采用结构光扫描仪对石膏模型扫描获得三维图像后,运用Geomagic Studio 13.0分析软件进行分析和测量,分别测量牙冠高度、宽度、牙弓长度和宽度,与手工测量方法进行比较和分析。结果 虽然三维数字化法与手工法测得的牙冠宽度、高度和牙弓长度的部分数值具有统计学差异,但不具有临床意义,组内相关系数均>0.75。结论 结构光数字化模型的准确性好,在临床的诊断和治疗过程中可替代石膏模型。     

食管癌小鼠模型研究进展

食管癌小鼠模型有三大类：化学致癌模型、异种移植瘤模型和遗传工程模型。化学致癌模型很好地模拟了人食管癌发生发展的病理过程,制备方法简单;异种移植瘤模型是目前最常用的食管癌动物模型,具有成瘤快、成瘤率高、成本低的优点;遗传工程模型涉及的基因主要有p53、Cyclin D1、Brcal和p120ctn,有助于了解肿瘤的生物学特征,但其价格昂贵且制备时间长。