平时罕见,特殊情况下发生的几种伤病

一些损伤和疾病平时罕见，特殊情况下可以发生，造成严重危害。特殊情况主要包括严重事故、灾害、战争、恐怖主义活动以及特殊环境与特殊作业的危害等。本阐述了现代战争中发生的贫铀武器伤害、燃料空气炸弹伤害、微波武器伤害和战时精神疾病；可能源于恐怖主义活动的炭疽、天花；严重事故性伤害中的核事故、化学事故和煤矿事故伤害；严重灾害中的地震、海难(海战)落海伤害。中介绍了这些伤病的发生情况、伤害特点与医学救治。     

富氧气体防护下暴发性缺氧大鼠大脑超微病理变化

目的 从亚细胞水平观察大鼠在12 000m高度暴发性缺氧及富氧气体防护时大脑顶叶皮质组织超微结构变化，为高空暴发性缺氧的防护和治疗提供理论依据。方法 将24只雄性Wistar大鼠随机分为地面对照组、3000m对照组、12000m暴发性缺氧组、12000m吸90％富氧气体防护组、12000m吸100％氧气防护组、12000m吸50％富氧气体防护组，每组4只。于低压舱内暴露于12000m高度30min，然后将动物即刻处死，取大脑顶叶皮质层组织，制成切片，透射电镜下观察。结果与地面对照组相比，随着吸氧浓度的降低，实验组缺氧程度加重，主要表现为脑组织神经细胞、神经胶质细胞结构模糊不清，核及胞质内线粒体、内质网扩张，突触小泡减少等，以12000m暴发性缺氧组及吸50％氧气防护组明显。结论 吸100％和吸90％富氧气体防护效果是理想的，与地面对照组和3000m对照组的结果无明显差别。     

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目的探讨丰富环境对大鼠惊厥性脑损伤是否具有保护作用。方法2004-08西安交通大学医学院对30只21日龄雄性SD大鼠经水浴法诱导反复惊厥10次后随机均分为长程丰富环境暴露组(LG)、短程丰富环境暴露组(SG)和对照组(CG)。LG、SG组分别暴露于丰富环境中10d和5d,CG组不给予干预措施。观察各组大鼠在避暗试验(passiveavoidancetest,PAT)、Morris水迷宫(Morriswatermaze,MWM)及旷场试验(openfieldtest,OFT)中学习记忆和情感行为的变化。结果丰富环境暴露可使反复惊厥大鼠在PAT中的记忆潜伏期延长[LG组为(323·42±98·38)s,SG组为(276·52±92·64)s,CG组为(197·13±95·11)s,P<0·01],错误反应次数减少(LG组为1·75±1·01,SG组为2·14±1·13,CG组为5·37±1·26,P<0·01);在OFT中,丰富环境暴露可增强反复惊厥大鼠的兴奋性(LG组得分为62·35±7·81,SG组为53·67±7·66,CG组为45·48±7·34,P<0·01),提高大鼠对陌生环境的适应能力(LG组后肢性站立的次数为33·37±4·74,SG组为26·18±4·23,CG组为17·19±4·31,P<0·01),改善大鼠的紧张情绪(LG组粪便粒数为3·85±2·01,SG组为6·14±1·98,CG组为11·62±2·12,P<0·01);在MWM中,丰富环境暴露可使反复惊厥大鼠逃逸潜伏期缩短,搜寻策略改善(LG、SG及CG组直线式搜寻策略所占百分比依次为37·8%、33·6%及27·2%,χ2=41·02,P<0·005)。结论丰富环境暴露可以改善反复惊厥大鼠的学习记忆和情感行为,对惊厥性脑功能损伤具有保护作用。     

Chronic exposure by ingestion of environmentally relevant doses of 226Ra leads to transient growth perturbations in fathead minnow (Pimephales promelas,Rafinesque, 1820)

Abstract

Purpose: To assess the impact of environmentally relevant levels of ingested ²²⁶Ra on a common freshwater fish species.

Methods: Fathead minnow (Pimephales promelas, Rafinesque) were obtained at the first feeding stage and established on a commercial fish food diet containing ²²⁶Ra in the activity range 10 mBq/g^?1, –10,000 mBq/g^?1. They remained on this diet for 24 months and were sampled invasively at 1,6,18 and 24 months to assess growth, biochemical indices and accumulated dose and non-invasively also at 12 and 15 months to assess growth.

Results: Fish fed 10 and 100 mBq/g^?1 diet showed a small transitory deregulation of growth at 6 and 12 months. Fish fed higher activities showed less significant or insignificant effects. There was a trend at 18 months which was stronger at 24 months for the population distribution to change in all of the ²²⁶Ra fed groups so that smaller fish were smaller and bigger fish were bigger than the controls. There were also significant differences in the ratios of protein:DNA at 24 months which were seen as a trend but were not significant at earlier time points.

Conclusions: Fish fed a radium diet for 2 years show a small and transitory growth dysregulation at 6 and 12 months. The effects predominate at the lower activities suggesting hormetic or homeostatic adjustments. There was no effect on growth of exposure to the high activities ²²⁶Ra. This suggests that radium does not have a serious impact on the ecology of the system and the level of radium that would be transferred to humans is very low. The results may be important in the assessment of long-term environmental impacts of ²²⁶Ra exposure.     

Transient enriched housing before amyloidosis onset sustains cognitive improvement in Tg2576 mice

Levels of educational and occupational attainment, as components of cognitive reserve, may modify the relationship between the pathological hallmarks and cognition in Alzheimer's disease (AD). We examined whether exposure of a Tg2576 transgenic mouse model of AD to environmental enrichment (EE) at a specific period during the amyloidogenic process favored the establishment of a cognitive reserve. We found that exposure to EE during early adulthood of Tg2576 mice—before amyloidogenesis has started—reduced the severity of AD-related cognitive deficits more efficiently than exposure later in life, when the pathology is already present. Interestingly, early-life exposure to EE, while slightly reducing forebrain surface covered by amyloid plaques, did not significantly impact aberrant inhibitory remodeling in the hippocampus of Tg2576 mice. Thus, transient early-life exposure to EE exerts long-lasting protection against cognitive impairment during AD pathology. In addition, these data define the existence of a specific life time frame during which stimulatory activity most efficiently builds a cognitive reserve, limiting AD progression and favoring successful aging.     

对工作场所F类铀化合物空气浓度限值的推导探讨

目的 从辐射和化学危害角度分别推算F类铀化合物导出空气浓度,为工作场所职业危害因素的管理与评价提供参考.方法 用模拟计算的方法,分别推算F类铀化合物达到个人年剂量限值、急慢性机体损害效应阈值时工作场所的空气浓度.结果 正常运行情况下,将工作场所空气中F类铀化合物浓度控制在5 μg/m³以内,可以满足辐射危害和化学危害控制的要求;短时间开放性接触时,控制在1.1 mg/m³是可以接受的.结论 制定F类铀化合物空气浓度限值是可行的.     

Neuroplasticity-related correlates of environmental enrichment combined with physical activity differ between the sexes

Environmental enrichment (EE), comprising positive physical (exercise) and cognitive stimuli, influences neuronal structure and usually improves brain function. The promise of EE as a preventative strategy against neuropsychiatric disease is especially high during early postnatal development when the brain is still amenable to reorganization. Despite the fact that male and female brains differ in terms of connectivity and function that may reflect early life experiences, knowledge of the neural substrates and mechanisms by which such changes arise remains limited. This study compared the impact of EE combined with physical activity on neuroplasticity and its functional consequences in adult male and female rats; EE was provided during the first 3 months of life and our analysis focused on the hippocampus, an area implicated in cognitive behavior as well as the neuroendocrine response to stress. Both male and female rats reared in EE displayed better object recognition memory than their control counterparts. Interestingly, sex differences were revealed in the effects of EE on time spent exploring the objects during this test. Independently of sex, EE increased hippocampal turnover rates of dopamine and serotonin and reduced expression of 5-HT_1A receptors; in addition, EE upregulated expression of synaptophysin, a presynaptic protein, in the hippocampus. As compared to their respective controls, EE-exposed males exhibited parallel increases in phosphorylated Tau and the GluN2B receptor, whereas females responded to EE with reduced hippocampal levels of glutamate and GluN2B. Together, these observations provide further evidence on the differential effects of EE on markers of hippocampal neuroplasticity in males and females.     

高浓缩钚材料贯穿辐射场计算方法研究

目的 为满足高浓缩钚材料操作人员辐射安全评价和核安全审评的要求,需要对高浓缩钚材料周围形成的贯穿辐射场进行计算分析,解决高浓缩钚材料发射的γ射线和中子射线贯穿机理和强度的计算问题。方法 本文在对高浓缩钚材料的组成及所含放射性核素的辐射特性进行深入分析的基础上,基于γ射线宽束减弱规律和中子分出截面理论,研究提出了适用于高浓缩钚材料γ剂量率和中子剂量率计算模式。结果 贴近高浓缩钚材料表面γ剂量率和中子通量理论计算值与实际测量值同一量级,表明计算模型是正确的。距离钚材料表面0、30、100 cm处γ剂量率实际测量值均大于计算值,并且距离越远相对误差越大;中子模拟计算值与实际测量值相对误差随距离的增加而减小。结论 通过原理分析和实测验证,证明本文提出的高浓缩钚材料辐射场计算方法是合理可行的,能够满足科学性和准确性要求。     

Impulse oscillometry measurement of distal airways obstruction in depleted uranium‐exposed Gulf War veterans

Introduction

A cohort of Gulf War I veterans who sustained exposure to depleted uranium undergoes biennial surveillance for potential uranium‐related health effects. We performed impulse oscillometry and hypothesized that veterans with higher uranium body burdens would have more obstructive abnormalities than those with lower burdens.

Methods

We compared pulmonary function of veterans in high versus low urine uranium groups by evaluating spirometry and oscillometry values.

Results

Overall mean spirometry and oscillometry resistance values fell within the normal ranges. There were no significant differences between the high and low uranium groups for any parameters. However, more veterans were classified as having obstruction by oscillometry (42%) than spirometry (8%).

Conclusions

While oscillometry identified more veterans as obstructed, obstruction was not uranium‐related. However, the added sensitivity of this method implies a benefit in wider surveillance of exposed cohorts and holds promise in identifying abnormalities in areas of the lung historically described as silent.