纳米氧化铈对小鼠辐射损伤防护作用的研究

目的 探讨纳米氧化铈(CeO₂)对小鼠辐射损伤的防护作用。方法 140只BALB/c小鼠随机分为正常对照组,照射对照组,阳性药物对照(氨磷汀)、纳米氧化铈低剂量组(100 mg/kg)、纳米氧化铈中剂量组(300 mg/kg)和纳米氧化铈高剂量(900 mg/kg)组。小鼠经3.5 Gy ⁶⁰Co γ射线一次性全身照射(剂量率1 Gy/min)。于照射后3天、8天处死小鼠,检测脾脏和胸腺系数和骨髓嗜多染红细胞微核率,并对照后8天小鼠血浆SOD和小鼠胸腺淋巴细胞肌动蛋白微丝骨架进行观测。结果 照后3天,与照射对照组相比,纳米氧化铈中、高剂量组的胸腺系数明显增加(P<0.05或P< 0.01),优于阳性药物组;纳米氧化铈用药组脾脏系数有升高的趋势,但差异无统计学意义;纳米氧化铈药物组骨髓嗜多染红细胞微核细胞率均降低,特别是低剂量组微核细胞率与照射对照组相比差异有统计学意义(P < 0.05),作用优于阳性药物组。照后8天,与照射对照组相比,纳米氧化铈药物组骨髓嗜多染红细胞微核细胞率持续降低;纳米氧化铈中剂量组小鼠血清总SOD活力有升高趋势,差异无统计学意义,胸腺淋巴细胞微丝骨架形态较完整。结论 纳米氧化铈具有一定的辐射防护作用,其机制可能与提高机体免疫能力、保护造血组织免于辐射诱发的损伤有关。     

基于冲击伤诊治思考

和平时期,由于爆破作业、恐怖袭击以及易爆危险品失控性爆炸,可造成严重的爆炸伤亡事故。回顾近十年来,严重爆炸事故在国内呈逐渐增多趋势,而爆炸冲击伤作为现场人员致死、致残的主要致伤原因,虽已引起国内医学界关注,但针对爆炸冲击伤的关注更多集中在诊治水平的渐进提升方面,对于爆炸冲击伤的防护研究虽已进行了积极探索,并在实验研究方面积累了许多数据,但在防护材料、防护装备以及防护策略的理论跟进和深度挖掘上亟待加强。笔者从冲击伤诊治角度反思了对冲击伤防护措施的现实需求,并结合冲击伤防护材料与装备研发现状,探讨了非战争性爆炸防护策略的精准性和适配性。这对于相当长的时期内,在尚无法杜绝爆炸事故发生条件下,无疑具有重大理论价值和现实指导意义。     

2,4-二氯-5-甲基嘧啶致刺激性接触性皮炎64例研究

目的 了解2,4-二氯-5-甲基嘧啶(DCP)致接触性皮炎的临床特征,探讨治疗方法及防护措施.方法 对2,4-二氯-5-甲基嘧啶致接触性皮炎的64例患者进行分析.参与企业防护措施的持续改进.结果 64例患者均在接触DCP后1～ 12 min,平均7 min发病.皮损发生于DCP接触部位,表现为边界清楚的水肿性红斑,10例出现水疱,皮损面积58～5 600 cm2.48例自觉灼痛,16例自觉瘙痒.4例头痛,3例恶心、呕吐,1例晕厥.10例在避免接触DCP 1 ～4 d后,于DCP非接触部位出现皮疹,自觉瘙痒.8例皮损组织病理均为表皮细胞内及细胞间水肿,海绵形成,5例表皮内水疱,7例真皮乳头水肿,有炎症细胞浸润.糖皮质激素治疗有效.正压式充气防护服能将作业工人与外界完全隔离,可避免DCP所致接触性皮炎的发生.结论 2,4-二氯-5-甲基嘧啶所致接触性皮炎为刺激性接触性皮炎,少数患者在接触DCP后会发生迟发型过敏反应.正压式充气防护服可起到有效防护.     

252Cf中子后装治疗室辐射防护的测量与分析

目的 通过现场测量,对某²⁵²Cf中子后装治疗室的实体防护效果和迷路内中子、γ辐射水平分布与变化规律进行分析,积累辐射防护屏蔽实验数据与经验,为职业照射的控制提供科学依据。方法 在²⁵²Cf中子后装治疗机运行时,分别采用中子周围剂量当量仪和X-γ剂量率仪测量治疗机房实体屏蔽墙外、迷路内各关注点的中子、γ辐射水平,并利用非线性模型对迷路内各关注点的中子、γ辐射水平与所处位置进行回归分析,分析治疗室的实体防护效果和迷路内各关注点的中子、γ辐射水平的变化规律。结果 结果表明,²⁵²Cf中子后装治疗室实体屏蔽外侧的中子、γ辐射水平处于本底水平。同时,治疗室迷路内中子、γ辐射水平随着与内入口的距离增加呈指数衰减趋势。结论 ²⁵²Cf中子后装治疗室的实体防护效果符合相关辐射防护要求。较长的迷路设置是降低治疗室防护门处剂量负担的一个行之有效方法。     

CRMP2在大鼠海马神经元中的表达分布及对神经元突起生长的影响

目的探讨脑衰反应调节蛋白2(CRMP2)在大鼠海马神经元中的表达分布及对神经元突起生长的影响。方法CRMP2及其模拟磷酸化质粒CRMP2-S522D、CRMP2-T555D,转入体外培养的SD大鼠海马神经元,转染72 h后,采用免疫印迹法和免疫荧光染色分析CRMP2、CRMP2-S522D、CRMP2-T555D在神经元中的分布差异以及对神经元突起分枝和突起长度的影响。结果 CRMP2及CRMP2-T555D在神经元胞体和突起均有分布,CRMP2-S522D则主要分布于胞体。CRMP2-T555D对神经元的突起长度和分枝数均没有明显影响;CRMP2-S522D对突起数目没有明显影响,但可以显著降低突起长度。结论 CRMP2的不同磷酸化形式在大鼠海马神经元中存在分布差异,并对神经元的突起长度产生影响。     

The alcohol clamp: applications, challenges, and new directions--an RSA 2004 symposium summary

This article summarizes the proceedings of a symposium organized and cochaired by Vijay Ramchandani and Sean O'Connor and presented at the 2004 Research Society on Alcoholism meeting in Vancouver, BC, Canada. The objectives of this symposium were: (1) to provide a rationale for the development and use of the alcohol clamp and the requirements for its use in alcohol challenge studies; (2) to highlight recent studies conducted using the alcohol clamp to identify sources of variation in the pharmacokinetics and pharmacodynamics of alcohol, as well as to address important research questions related to the relationship between the response to alcohol and the risk for alcoholism; and (3) to provide a perspective on progress, address limitations of the clamp, and identify new directions for alcohol challenge research. The symposium began with an introduction and overview of the alcohol clamp, by Vijay Ramchandani. This was followed by 4 presentations that highlighted recent studies conducted using the clamp including: (1) determination of the influence of alcohol dehydrogenase polymorphisms on alcohol elimination rates in a male Jewish population, by Yehuda Neumark; (2) examination of family history of alcoholism, recent drinking history, and levels and rates of administration as determinants of the response to alcohol and risk for alcoholism, by Sean O'Connor; (3) evaluation of the time course of ethanol intoxication on neuroendocrine function in humans, by Ulrich Zimmermann; and (4) a study of the effects of steady-state blood alcohol levels on auditory event-related potentials in rats, by Sandra Morzorati. Harriet de Wit summarized and discussed the research presented at the symposium and provided her perspective on future directions for research using the alcohol clamp.     

Genetic and other contributions to alcohol intake in rhesus macaques (Macaca mulatta)

BACKGROUND: The etiology of alcoholism and alcohol abuse, like many other complex diseases, is heterogeneous and multifactorial. Numerous studies demonstrate a genetic contribution to variation in the expression of alcohol-related disorders in humans. Over the past decade, nonhuman primates have emerged as a valuable model for some aspects of human alcohol abuse because of their phylogenetic proximity to humans. Long-term, longitudinal studies of rhesus macaques (Macaca mulatta) have provided much insight into environmental influences, especially early life experiences, on alcohol consumption and behavior patterns that characterize alcohol intake later in life. It is not known, however, whether there is a genetic component as well to the variation seen in alcohol consumption in rhesus macaques. A significant genetic component to variation in alcohol consumption in rhesus macaques would show for the first time that like humans, for nonhuman primates additive genetic influences are important. Moreover, their use as a model for alcohol-related disorders in humans would have even greater relevance and utility for designing experiments incorporating the expanding molecular genetics field, and allow researchers to investigate the interaction among the known environmental influences and various genotypes. METHODS: In this study, we investigate factors contributing to variation in alcohol consumption of 156 rhesus macaques collected over 10 years when subjects were adolescent in age, belonging to a single extended pedigree, with each cohort receiving identical early rearing backgrounds and subsequent treatments. To measure alcohol consumption each animal was provided unfettered simultaneous access both to an aspartame-sweetened 8.4% (v/v) alcohol-water solution, the aspartame-sweetened vehicle, and to water for 1 hour each day during the early afternoon between 13:00 and 15:00 in their home cages for a period of 5 to 7 weeks. We use multiple regression to identify factors that significantly affect alcohol consumption among these animals and a maximum likelihood program (ASReml) that, controlling for the significant factors, estimates the genetic contribution to the variance in alcohol consumption. RESULTS: Multiple regression analysis identified test cohort and rearing environment as contributing to 57 and 2%, respectively, of the total variance in alcohol consumption. Of the remaining 41% of the variance about half (19.8%) was attributable to additive genetic effects using a maximum likelihood program. CONCLUSION: This study demonstrates that, as in humans, there are additive genetic factors that contribute to variation in alcohol consumption in rhesus macaques, with other nongenetic factors accounting for substantial portions of the variance in alcohol consumption, Our findings show the presence of an additive genetic component and suggest the potential utility of the nonhuman primate as a molecular genetics tool for understanding alcohol abuse and alcoholism.     

Individual contributions of the human metapneumovirus F, G, and SH surface glycoproteins to the induction of neutralizing antibodies and protective immunity

We evaluated the individual contributions of the three surface glycoproteins of human metapneumovirus (HMPV), namely the fusion F, attachment G, and small hydrophobic SH proteins, to the induction of serum HMPV-binding antibodies, serum HMPV-neutralizing antibodies, and protective immunity. Using reverse genetics, each HMPV protein was expressed individually from an added gene in recombinant human parainfluenza virus type 1 (rHPIV1) and used to infect hamsters once or twice by the intranasal route. The F protein was highly immunogenic and protective, whereas G and SH were only weakly or negligibly immunogenic and protective, respectively. Thus, in contrast to other paramyxoviruses, the HMPV attachment G protein is not a major neutralization or protective antigen. Also, although the SH protein of HMPV is a virion protein that is much larger than its counterparts in previously studied paramyxoviruses, it does not appear to be a significant neutralization or protective antigen.     

What protects older Romanians in Switzerland from loneliness? A life-course perspective

The topic of loneliness among older migrants has recently gained scholarly interest. There is a particular focus on why older migrants are generally lonelier than their non-migrant peers from the destination. These studies neglect variations both within and between older migrant groups. Our qualitative study is innovative for three reasons. First, it focuses on Romanian migrants aged 65+ who fled communism and aged in place in Switzerland—an understudied population of former political refugees that experiences little or no loneliness in later years. Second, it takes a life-course approach to explore experiences of loneliness during communist Romania, in the context of migration and later in life. Third, it focuses on protective and coping factors rather than risk factors. Having been through hard times in communist Romania—marked by fear and distrust among people and estrangement from society—older Romanian migrants built strength to withstand difficult times, learned to embrace solitude, and/or to relativise current hardships, if any. Upon arrival many founded or joined an association or church, which offers the opportunity to establish a sustainable social network consisting of a large pool of Romanian non-kin with a shared past and experience of migration and integration, to counteract social losses in later life. When moments of loneliness cannot be prevented (e.g. due to death of a spouse), they try to be active to distract from loneliness or ‘simply’ accept the situation. These aspects need to be taken into account in future research and when developing loneliness interventions.