早期听力损害后脑电功率的变化

目的 探索早期听力受损后脑电功率的变化.方法 对42例早期听力受损的儿童及33例听力正常儿童对比研究其脑电图和脑电绝对功率值.结果 早期听力受损儿童的左侧额部、颞部、枕部等多个脑区的脑电绝对功率值在δ,θ,α,δ θ/α β等频段、以及左侧总功率均低于同龄正常儿(t=2.21～3.74,P＜0.01).结论 听觉中枢发育早期缺乏有效的声音信号刺激而不能成熟,使相应功能区的脑细胞活动水平低下,脑电绝对功率值低于正常儿童.     

基于多变量相空间重构的癫痫脑电分析

目的：应用多变量相空间重构对分析脑电信号,获取癫痫脑电的非线性特征.方法：鉴于脑电（EEG）的高维混沌特性,通过多变量相空间重构分析方法,将大脑分为左右2个半区,分别以8个EEG导联作为重构样本进行非线性分析,可以得到线性区域,从而得到相关维数的估计值.结果：5例确诊癫痫患者的脑电分析结果基本一致,癫痫发作前、中、后期相关维数有明显变化,与对照组的结果差异显著.结论：多变量相空间重构法适用于对短时含噪声的时间序列进行分析,能够避免延迟时间和嵌入维数等参数的选择,得到更可靠的结果.     

大鼠脑铅和血铅含量对学习记忆的影响与硒锌的保护作用

目的　探讨食物铅进入机体后对记忆功能的影响以及补充锌和硒对铅致损伤的保护作用。方法　将Wistar大鼠按体重随机分为 10组 ,在基础饲料里分别添加不同剂量的亚硒酸钠、乳酸锌及醋酸铅 ,实验期为 12周。结果　染铅各组大鼠的脑和全血中铅含量均显著高于对照组。在染铅各组中 ,从低硒缺锌到高硒高锌组大鼠的脑铅含量呈下降趋势 ,对照组大鼠的脑铅含量未检出。染铅各组大鼠血铅含量也不同程度地受饲料中硒和锌水平的影响 ,硒和锌对降低脑铅含量有协同作用 (P <0 0 0 1)。各组大鼠发生错误次数和到达终点所需时间明显不同 ,缺锌低硒染铅组发生的错误次数和所需时间显著高于其他染铅各组和对照组(P <0 0 5 ) ;补硒可显著改善染铅大鼠水迷宫实验所需时间和降低错误次数 (P =0 0 0 2和P =0 0 0 7)。大鼠水迷宫试验中随着脑铅和血铅含量的增加 ,到达终点所需时间延长和发生的错误次数增加。结论　良好的锌和硒营养状况有助于降低组织中铅的水平 ,提示可能具有拮抗铅毒性的作用     

铅作业工人脑电图及脑电地形图的改变

目的探讨铅作业工人脑电图和脑电地形图的改变.方法本文通过铅排版作业工人(35名)与正常健康人群(35名)的比较,采用神经电生理的方法分别从定性和定量两方面评价低水平铅接触工人的脑电图和脑电地形图的异常改变.结果铅作业工人的脑电图特征瘟主波率明显减少, β主波率增加,低波幅(占45.71%),广泛性异常(17.14%)和弥散性异常(28.57%)增多 .脑电地形图特点为高功率值,θ频带异常分布,以弥散性损害为著,δ功率值在F7-A1(左前颞)区较正常组升高,β功率值在FP2-A2(右额极)区较正常组升高,β功率值在C4-A2(右中央)区较正常组人群升高.结论发现低水平铅接触影响作业工人的脑电活动,出现异常脑电波.     

脑电信号相关维数的计算参数研究

为研究在计算临床脑电的相关维数时有关计算参数对结果的影响,及参数的最佳选择,为研究和诊断提供参考的标准,我们选取不同的参数:分析点数(N=1000～9000)、嵌入维数(m=1～30)、延迟时间(τ=1～30),对脑电信号的相关维数指标进行分析比较。结果发现:(1)脑电信号的相关维数,在不同的参数条件下得到不同的相关维数值;(2)参数在比较小的时候对计算结果的影响比较大;(3)相关维数在相应参数大于一定值的时候趋于稳定,在下列条件下表现出稳定性:分析点数N>2000(即数据时间>20s),嵌入维数m>15,延迟时间τ>6。因此,在计算时可以选取尽可能小的参数值以便减少计算时间,而且不影响分析结果的精度。     

基于多变量相空间重构法的癫痫脑电研究

鉴于脑电(EEG)的高维混沌特性,通过多变量相空间重构分析方法,将大脑分为左右两个半区,分别以8个EEG导联作为重构样本进行非线性分析,可以得到线性区域,进而更好地得到相关维数的估算值.为了检验算法的可行性,我们先用低维的Lorenz系统从数据量的要求进行试算,然后从时间的遍历性上进一步验证,并将其应用于正常人和癫痫患者脑电的分析,得到高维数值.与其他研究者的结果进行比较,结果表明:多变量相空间重构法适用于短时含噪声的时间序列,能够避免延迟时间和嵌入维数等参数的选择,得到更可靠的结果.     

牛磺酸对低水平染铅大鼠生长发育的影响

目的：探讨牛磺酸对低水平染铅大鼠生长发育的影响。方法：用0．14％醋酸铅蒸馏水建立大鼠低水平染铅模型，从行为毒理学角度观察补充不同浓度牛磺酸是否能保护其子代正常生长发育，并测定幼鼠血铅、脑铅含量。结果：（1）各牛磺酸补充组的幼鼠脑铅含量均低于铅对照组，但高于对照组（P＜0．01）。（2）负向趋地、听觉惊愕、触须定位达标时间（天）各铅加牛磺酸组均短于铅对照组（P＜0．01）。结论：补充牛磺酸可以减少铅在幼大鼠脑内蓄积，防止铅毒性所致幼大鼠的行为发育迟缓。     

消除趋势波动分析方法用于大鼠脑电分析

用消除趋势波动分析方法(detrendedfluctuationanalysis,DFA)对大鼠正常脑电和癫痫脑电时间序列进行分析,计算得到的标度指数表明,大鼠癫痫脑电具有长程相关性,其未来变化趋势与过去变化趋势一致,大鼠正常脑电则具有颤动噪声动力学性质(flicker -noisedynamics) ,表明生物系统处于自组织评判状态。     

染铅大鼠子代脑铅含量及对神经行为功能的影响

为探讨染铅大鼠子代脑铅含量及对神经行为功能的影响, 将Ｗｉｓｔａｒ 大鼠６０ 只随机分成高、中、低剂量和对照组, 进行醋酸铅饮水染毒实验。结果显示： 染毒各组大鼠子代脑铅含量均高于对照组, 呈随染毒剂量增加而增高的趋势。悬崖回避试验阳性率较对照组低且有显著差异（ Ｐ＜ ０－０１） ; 学习、记忆功能染毒各组均比对照组时间明显延长（ Ｐ＜ ０－０１） 。提示： 铅通过母体对子代造成脑铅的蓄积, 导致早期行为发育和学习记忆功能的损害。     

运用功率谱的方法分析大鼠癫痫模型的脑电信息

癫痫是严重危害人类健康的脑部常见病,以脑部神经元过度放电引起突然反复和短暂的中枢神经系统功能失常为特征.脑电活动具有混沌特征,且具有较强的非平稳性,癫痫的发作期或在两次发作的间期有异常放电,统称为痫性放电.功率谱测量的是信号在单位时间内所具有的能量,它反映了信号的频率特性,可以作为区别确定性混沌与随机信号的指标.研究表明大鼠癫痫模型癫痫放电过程的脑电信息具有确定性混沌运动特性,说明可以运用混沌运动理论去研究癫痫脑电的放电过程.     

The human drama of genetics: 'hard' and 'soft' media representations of inherited breast cancer

This paper examines media coverage of 'breast cancer genetics', and explores its implications for public understanding. We present a content analysis of coverage in British newspapers and look at a variety of popular forms, including women's magazines, television soap opera and radio drama. Genetic/inherited risk receives a great deal of coverage across a wide range of media formats and outlets. Much of this attention has focused on individuals from 'high risk families' and dilemmas around prophylactic mastectomies. Through examining media coverage, combined with interviews with media personnel and their sources, we show why this story proved so attractive to the media and highlight the different production values which influence coverage. Finally, we introduce preliminary findings from focus group discussions to demonstrate how such 'human interest' framing has engaged audience attention and influenced public understandings. The paper concludes by highlighting the implications for analysing, predicting, and engaging with, media representations of science.     

Worker education in the primary prevention of occupational dermatoses

This paper reports the evaluation of a skin care education programmeconducted on a fine chemicals manufacturing site where over1,000 employees are located. Approximately 60% are involvedin chemical manufacture. Over a 12 month period production staffreceived training in prevention of occupational dermatoses linkedto a site-wide poster initiative. The incidence of new casesof occupational dermatoses fell from 0.055 (70 cases in 1,277employees) to 0.021 (27 cases in 1,277 employees) before andafter the intervention respectively (p<0.0001). After otherfactors such as chemicals handled, observer bias and changesin reporting related to socioeconomic climate were taken intoaccount it is concluded that this study demonstrates the importanceof worker education as a tool for primary prevention of disease.Training materials such as video and poster presentations maybe effectively used in the chemical manufacturing industry asan adjunct to prevention and control of exposure to substanceshazardous to the skin. Such methods may also be used in otherindustries where there are significant risks of dermatoses.     

Regional Variation in Travel-related Illness acquired in Africa,March 1997–May 2011

To understand geographic variation in travel-related illness acquired in distinct African regions, we used the GeoSentinel Surveillance Network database to analyze records for 16,893 ill travelers returning from Africa over a 14-year period. Travelers to northern Africa most commonly reported gastrointestinal illnesses and dog bites. Febrile illnesses were more common in travelers returning from sub-Saharan countries. Eleven travelers died, 9 of malaria; these deaths occurred mainly among male business travelers to sub-Saharan Africa. The profile of illness varied substantially by region: malaria predominated in travelers returning from Central and Western Africa; schistosomiasis, strongyloidiasis, and dengue from Eastern and Western Africa; and loaisis from Central Africa. There were few reports of vaccine-preventable infections, HIV infection, and tuberculosis. Geographic profiling of illness acquired during travel to Africa guides targeted pretravel advice, expedites diagnosis in ill returning travelers, and may influence destination choices in tourism.     

The design of hazard risk assessment matrices for ranking occupational health risks and their application in mining and minerals processing

Two hazard risk assessment matrices for the ranking of occupational health risks are described. The qualitative matrix uses qualitative measures of probability and consequence to determine risk assessment codes for hazard-disease combinations. A walk-through survey of an underground metalliferous mine and concentrator is used to demonstrate how the qualitative matrix can be applied to determine priorities for the control of occupational health hazards. The semi-quantitative matrix uses attributable risk as a quantitative measure of probability and uses qualitative measures of consequence. A practical application of this matrix is the determination of occupational health priorities using existing epidemiological studies. Calculated attributable risks from epidemiological studies of hazard-disease combinations in mining and minerals processing are used as examples. These historic response data do not reflect the risks associated with current exposures. A method using current exposure data, known exposure-response relationships and the semi-quantitative matrix is proposed for more accurate and current risk rankings.     

Psychopathological features of a patient population of targets of workplace bullying

BACKGROUND: A strong association between workplace bullying and subsequent anxiety and depression, indicated by empirical research, suggests that bullying is an aetiological factor for mental health problems. AIMS: To evaluate levels of stress and anxiety-depression disorder developed by targets of workplace bullying together with outcome at 12 months and to characterize this population in terms of psychopathology and sociodemographic features. METHODS: Forty-eight patients (36 women and 12 men) meeting Leymann Inventory of Psychological Terror criteria for bullying were included in a prospective study. Evaluations were performed at first consultation and at 12 months using a standard clinical interview, a visual analogue scale of stress, the Hospital Anxiety and Depression (HAD) scale, the Beech scale of stress in the workplace and a projective test (Picture-Frustration Study). RESULTS: At first consultation, 81% of patients showed high levels of perceived stress at work and 83 and 52% presented with anxiety or depression, respectively. At 12 months, only 19% of working patients expressed a feeling of stress at work. There was a significant change in symptoms of anxiety while there was no change in symptoms of depression. Stress at work and depression influenced significatively capacity to go back to work. At 12-month assessments, workers showed a significantly better score on the HAD scale than non-workers. Over half the targets presented a neuroticism-related predominant personality trait. CONCLUSION: Workplace bullying can have severe mental health repercussions, triggering serious and persistent underlying disorders.     

The rise and fall in incidence of malignant mesothelioma from a British Naval Dockyard, 1979-1999

BACKGROUND: The incidence of malignant mesothelioma in Britain is predicted to rise over the next 15-25 years because of past failure to protect the workforce against inhalation of asbestos. In British Naval dockyards, alternative insulation materials and respiratory protection were introduced from the mid-1960s. Aims This study was carried out to investigate the effects of these control measures on mesothelioma deaths in dockyard workers. METHODS: Cases of mesothelioma of the pleura and peritoneum between 1979 and 1999 in workers from the Devonport Naval Dockyard, south-west England, were sought from coroners' and medico-legal records. RESULTS: Three hundred and one cases were identified, 7% peritoneal. The peak incidence occurred in 1991 with 25 cases per annum (quadratic model fit R(2) = 74.2%, P < 0.001) and we predict that by 2003 the incidence will fall to fewer than five cases per annum. The mean time between first exposure and presentation was 48.5 years [95% confidence interval (CI) = 47.3-49.8], but this was significantly shorter in the more heavily exposed trades, when compared with the less heavily exposed (42 years, 95% CI = 39.0-45.0, versus 49.5 years, 95% CI = 48.2-50.9). Those with higher exposure were also at significantly greater risk of peritoneal disease (P < 0.023, Fisher's exact test). CONCLUSION: The reduction in incidence of mesothelioma is greater than can be accounted for by reduction in numbers of dockyard workers over the last 50 years. Changes in insulation materials and improved industrial hygiene measures introduced into the Devonport Dockyard from the mid-1960s have resulted in an earlier decline in the incidence of malignant mesothelioma than that predicted for the British workforce as a whole.     

Organophosphate toxicity and occupational exposure

The ubiquitous organophosphates present a continuing health hazard in agriculture, public health eradication programmes and as chemical warfare agents. Despite significant progress in understanding the potential mechanisms of toxicity far beyond the commonly accepted mechanism of cholinesterase inhibition in intentional exposures, the precise health effects following occupational exposures are yet to be completely defined. A much greater understanding exists of the clinical features of organophosphate poisoning. These are characterized by a triphasic response involving an initial acute cholinergic phase, an intermediate syndrome (both associated with high mortality) and a disabling but non-lethal delayed polyneuropathy. The delayed polyneuropathy may occur in the absence of the cholinergic or intermediate phases. However, progress is still required in order to improve the quantification and assessment of occupational exposures and the implementation of appropriate preventive measures. Finally, evidence-based guidelines for appropriate or optimal therapeutic interventions following poisoning are required urgently and collaborative work with colleagues in developing countries, where the occurrence of organophosphate exposures is more frequent, may provide the answers.     

Miliaria rubra of the lower limbs in underground miners

This report documents a case series of miliaria rubra of the lower limbs in miners at a deep underground metalliferous mine in tropical arid Australia. During the summer months of February and March 1999, all cases of miliaria rubra of the lower limbs in underground miners seen at the mine's medical centre were clinically examined and administered a questionnaire. Twenty-five patients were seen, an incidence of 56.4 cases per million man-hours. Miliaria rubra was most often located between the ankle and knee (88% of cases). Twenty-four percent had concurrent folliculitis and 20% had concurrent tinea. Thirty-two percent had a personal history of asthma. Walking through ground-water and splashing of the legs was common. Three to 4 weeks of sedentary duties in air conditioning was generally required to achieve resolution of miliaria rubra. The incidence of miliaria rubra of the lower limbs is 38% of the incidence of heat exhaustion at the same mine. The length of disablement is greater, however. Atopics may be at increased risk of miliaria rubra. Control measures are discussed.     

Planning research

The starting point for any research project should be a question.Once this has been defined and the relevant scientific literaturereviewed, a protocol should be drawn up. This will be used notonly as a guide to the conduct of the study and in the preparationof the final report, but also in seeking any financial supportand approvals that are required for the investigation. A protocolis normally arranged in sections covering the background tothe study, the question(s) that it will address, the methodsthat will be used for the collection and analysis of data, thestatistical power of the investigation (where relevant), anyethical considerations, and the financial input that will beneeded. A pilot study is often helpful where aspects of thestudy method are untried or of uncertainvalidity.     

Stress in the Norwegian police service

BACKGROUND: High levels of stress have been attributed to the conditions of police work, but there is little empirical evidence for this. AIMS: To develop a new instrument to measure job stress in the police; to assess the most severe and frequent police stressors; to compare levels of stress according to the demographic and organizational factors; and to study stress in relation to personality traits, work locus of control and coping strategies. METHODS: A comprehensive nationwide questionnaire survey of 3272 Norwegian police at all hierarchical levels, including the Norwegian Police Stress Survey (NPSS), the Job Stress Survey, the Basic Character Inventory, the Work Locus of Control Scale, and the Coping Strategies Scale. RESULTS: Work injuries were appraised as the most stressful but least frequent stressor and job pressure was reported the least severe but most frequent stressor. Females experienced job stressors less frequently, but appraised them as more severe than men did. Older police officers reported more job pressure severity and fewer work injuries. The police in districts where peer support was planned but not implemented, and who worked in districts with more than 50,000 inhabitants, perceived the lack of support more severely than others. The correlations between stress and personality traits, work locus of control, and coping were moderate. CONCLUSIONS: The NPSS captures police-specific stressors that are not adequately measured by global stress instruments. The study of stress in police work should preferably involve a nationwide use of police-specific stress instruments.