Effects of short-term xylene exposure on psychophysiological functions in Man

Summary Six male students were exposed to m-xylene at concentrations of 4.1–8.2 mol/1 (100–200 ppm) in an exposure chamber for several successive days, 6 h a day during two subsequent weeks to assess the effects of xylene on psychophysiological functions such as equilibrium, reaction time and critical flicker fusion. The influence on these functions by different exposure patterns constituting stable (4.1-8.2 mol/1) and periodically varying m-xylene concentrations (4.1–16.4 mol/l; 100–400 ppm) in inhaled air was also studied. During the study the subjects acted as their own controls. An inhalation exposure to m-xylene already at a concentration of 4.1 mo1/1 was observed to have a deleterious acute effect on the equilibrium and the reaction time performance of nonadapted human subjects. Adaptation to the test situation or tolerance seemed to develop against these effects over five subsequent exposure days, but the effects were again discernible in the following week, and were most pronounced when the exposure constituted peak concentrations which exceeded twofold any previous ones. In this study the effect of xylene seemed to be related to the level of xylene in the blood.     

Effects of occupational exposure to mercury vapour on the central nervous system.

Possible effects of mercury on the central nervous system (CNS) were examined in a group of chloralkali workers exposed to mercury (n = 89) and compared with a control group (n = 75), by registration of subjective symptoms, personality changes, forearm tremor, and performance on six computerised psychometric tests in the two groups. The groups were similar in age, education, verbal comprehension, and work tasks. In the chloralkali group, median blood mercury concentration (B-Hg) was 55 nmol/l, serum mercury concentration (S-Hg) 45 nmol/l, and urine mercury concentration (U-Hg) 14.3 nmol/mmol creatinine (25.4 micrograms/g creatinine). Corresponding concentrations in the control group were 15 nmol/l, 4 nmol/l, and 1.1 nmol/mmol creatinine (1.9 micrograms/g creatinine) respectively. The number of self reported symptoms, the scores for tiredness and confusion in the profile of mood states (POMS), and the degree of neuroticism in the Eysenck personality inventory (EPI), were significantly higher in the mercury exposed group compared with the controls. Performance on the psychometric tests and tremor frequency spectra did not differ significantly between the two groups. Dose-response calculations showed weak but statistically significant relations between symptom prevalence and current mercury concentrations in both blood and urine. The performance on three of the psychometric tests was negatively correlated with earlier peak exposures. The findings indicate a slight mercury induced effect on the CNS among the chloralkali workers.     

Effects of occupational exposure to mercury vapour on the central nervous system.

Possible effects of mercury on the central nervous system (CNS) were examined in a group of chloralkali workers exposed to mercury (n = 89) and compared with a control group (n = 75), by registration of subjective symptoms, personality changes, forearm tremor, and performance on six computerised psychometric tests in the two groups. The groups were similar in age, education, verbal comprehension, and work tasks. In the chloralkali group, median blood mercury concentration (B-Hg) was 55 nmol/l, serum mercury concentration (S-Hg) 45 nmol/l, and urine mercury concentration (U-Hg) 14.3 nmol/mmol creatinine (25.4 micrograms/g creatinine). Corresponding concentrations in the control group were 15 nmol/l, 4 nmol/l, and 1.1 nmol/mmol creatinine (1.9 micrograms/g creatinine) respectively. The number of self reported symptoms, the scores for tiredness and confusion in the profile of mood states (POMS), and the degree of neuroticism in the Eysenck personality inventory (EPI), were significantly higher in the mercury exposed group compared with the controls. Performance on the psychometric tests and tremor frequency spectra did not differ significantly between the two groups. Dose-response calculations showed weak but statistically significant relations between symptom prevalence and current mercury concentrations in both blood and urine. The performance on three of the psychometric tests was negatively correlated with earlier peak exposures. The findings indicate a slight mercury induced effect on the CNS among the chloralkali workers.     

围产期铅暴露对胎儿神经系统的影响

铅是一种广泛存在的具有神经毒性的重金属元素,发育期的神经系统对铅尤为敏感,围产期即使低浓度铅暴露,也可以对胎儿的神经系统造成损伤,该文从多方面就铅对胎儿神经损伤的可能机制及其防治进展进行综述。     

体育锻炼对学生身体自我影响的元分析

目的定量研究体育锻炼对学生身体自我的作用效应,为学校体育活动的科学安排提供参考。方法采用元分析方法(m e-ta-analysis),搜集38篇符合本文分析要求的研究论文,总样本量为3 380人。结果体育锻炼对学生身体自我影响的效应量在0.29~0.51之间,属于中等效应。不同量表测量的身体自我存在差异。体育锻炼对身体自我不同方面影响的效应量有所不同,其中运动技能成分影响最大,身体吸引力影响最小。体育锻炼与身体自我存在一定的"剂量-效应"关系,效应量还受性别、锻炼项目以及锻炼行为习惯等因素的影响。结论体育锻炼对学生身体自我有积极影响,应加强对非经常锻炼群体的研究。     

Acute effects of 1,1,1-trichloroethane inhalation on the human central nervous system

 The object of this study was to examine the immediate nervous effects of variable 1,1,1-trichloroethane (TCE) exposure combined with physical exercise. The effects on the quantitative electroencephalography (EEG), visual evoked potentials (VEP) and body sway were analyzed. Nine male volunteers were exposed to either a stable or a fluctuating exposure pattern with the same time-weighted average concentration of 200 ppm (8.1 μmol/l). In both cases, the subjects engaged in physical exercise during the exposures. Exercise alone induced an increase in the dominant alpha frequency in the EEG and, after an initial drop, an increase in the alpha percentage with a concomitant decrease in theta, whereas delta and beta bands remained unaffected. By contrast, exposure to TCE and exercise did not affect the alpha, theta or delta activities but induced changes in beta during the morning recordings at peak exposure to TCE. The body sway tended to decrease slightly during the fluctuating TCE exposure, and the later peaks in VEPs showed slight prolongations. Overall, no deleterious effects of exposure were noted. Received: 27 July 1995/Accepted: 8 March 1996     

Effects of exercise on the physical fitness and functionality of people with amputations: Systematic review and meta-analysis

Study designsystematic review and meta-analysis.BackgroundDespite existing scientific evidence alluding to the positive effects of physical exercise on people with amputations, there is a lack of consistency between the results of past studies.ObjectiveTo identify if people with amputations taking part in an exercise training programme can benefit from improvements in their health status as measured by changes in their physiological fitness and functionality levels.MethodsA systematic review and meta-analysis of randomized controlled trials (RCTs) were performed after searching within several databases up to October 2019.ResultsTen RCTs with satisfactory methodological quality were found. Five RCTs were pooled in the meta-analysis. Exercise programmes with a combination of activities were most commonly delivered. Exercise had positive effects on aerobic and muscular fitness parameters. Findings from the meta-analysis indicated that exercise improved distance walked but did not have a significant impact on functional mobility or self-reported functional capacity.ConclusionCombined exercise of muscular endurance and functional physical exercise appear to have greater positive effects on cardiorespiratory fitness, muscular fitness and functionality levels in adult prosthesis users with unilateral lower limb amputation. Future studies should include different profiles of patients with amputations that are poorly represented in the current scientific literature.     

体育运动对青春期少女骨密度的影响

目的：比较有规律和无规律的体育活动对青春期少女骨密度的影响。方法：采用双能X线骨密度测量仪,于观察前后分别测量年龄在10－12岁的少女运动员（60名）和普通学生（90名）身体多部位的骨密度,比较 两组少女骨密度在1年中的变化情况。结果：观察前,2组学生骨密度基线检查表明,运动员组除头部以外,上肢、下肢、骨盆及全身的骨密度值明显于高对照组（0．060－0．124g/cm^2）;观察1年后,以上5个部位的骨密度值均为运动员组明显高于对照组（0．087－0．187g/cm^2）,而且,骨密度变化值（增长值）仍为运动员组明显高于对照组（0．027－0119g/cm^2）,此外,两组调查对象在食物摄入频度和性特发育方面差异无显性。结论：运动组青春期少女骨密度增长有显的促进作用。     

Risk of chronic effects on the central nervous system at low toluene exposure

This study evaluates the chronic effects on the central nervous system of exposure to low concentrations of toluene (TWA < 20 ppm) on workers in a rotogravure plant. Ninety-eight male workers from a selection pool of 107 (92%) were examined neuropsychologically using a Cognitive Function Scanner, and neurologically by computerized methods measuring co-ordination ability, tremor and position stability. In addition measures of symptoms and former exposure were obtained by questionnaire. The workers were divided into three groups: Group 0 with no exposure to organic solvents (n = 19); Group 1 with exposure to TWA < 20 ppm of toluene for less than 13 years (n = 30) and Group 2 with exposure for more than 12 years (n = 49). Within Group 2, 37 (75%) had been exposed at levels exceeding 100 ppm for 10+ years before 1983. No significant differences were found between Group 0 and Group 1 regarding symptoms and results of the applied tests. Group 2 differed significantly from the two other groups in scoring higher on a symptom index (p = 0.04), particularly regarding concentration ability, reduced memory and fatigue. Group 2 scored significantly poorer on tests for visuospatial function, number learning and word recognition, while no differences regarding neurological functions were observed. The study showed no differences regarding neuropsychological and neurological functions between a non-exposed group of male workers and workers exposed to toluene less than 13 years at TWA < 20 ppm. However, long-term exposure to TWA (time weighted average) of toluene exceeding 100 ppm was associated with impaired neuropsychological function.     

Occupational exposure and defects of the central nervous system in offspring: review

A study of published work was carried out in a search for evidence of a causal role for parental occupational exposure in the origin of structural and functional defects of the central nervous system (CNS) in children. Studies that consider this topic are scarce and mostly refer to broad categories of exposures and effects. Non-occupational studies referring to environmental exposure of humans and studies on experimental animals were also reviewed. The studies on animals provided straightforward evidence about morphological and behavioural abnormalities resulting from some agents used occupationally. The studies on humans yielded a scala of defects that could be ascribed to exposure to high doses of various agents in the environment. Evidence for a causal role of occupational exposure has not been found, but a highly probable influence on the developing CNS is hypothesised for lead, methyl mercury, and ionising radiation. Parental occupational exposure to cadmium, organic solvents, anaesthetics, and pesticides may also play a part in causing defects of the CNS. Well designed future research is needed to test the above hypotheses.     

Occupational exposure and defects of the central nervous system in offspring: review.

A study of published work was carried out in a search for evidence of a causal role for parental occupational exposure in the origin of structural and functional defects of the central nervous system (CNS) in children. Studies that consider this topic are scarce and mostly refer to broad categories of exposures and effects. Non-occupational studies referring to environmental exposure of humans and studies on experimental animals were also reviewed. The studies on animals provided straightforward evidence about morphological and behavioural abnormalities resulting from some agents used occupationally. The studies on humans yielded a scala of defects that could be ascribed to exposure to high doses of various agents in the environment. Evidence for a causal role of occupational exposure has not been found, but a highly probable influence on the developing CNS is hypothesised for lead, methyl mercury, and ionising radiation. Parental occupational exposure to cadmium, organic solvents, anaesthetics, and pesticides may also play a part in causing defects of the CNS. Well designed future research is needed to test the above hypotheses.     

体育锻炼对孕期抑郁治疗效果的Meta分析

目的 抑郁已经成为威胁心理健康的重要疾病,孕期抑郁会对孕妇、胎儿及新生儿产生不良影响,适宜的锻炼干预是改善孕期抑郁的重要手段,而明确更加合理的锻炼干预方案,对治疗孕期抑郁具有重要作用。采用Meta分析法,探讨锻炼干预对孕期抑郁的影响,并进一步分析可能产生较大干预效应的锻炼方案,以期为今后该领域的锻炼干预研究及临床护理提供参考。方法 通过 PubMed、EMBase、The Cochrane Library、Web of Science、中国知网（CNKI）、中国生物医学文献数据库（CBM）等数据库,检索有关孕期锻炼对抑郁影响的相关文献,采用Cochrane偏倚风险评估工具对纳入的研究进行方法学质量评估并采用改良Jadad进行评分,采用Review Manager 5.4软件对文献数据进行统计学分析。结果 共纳入13篇文献,总样本量为1256例。Meta分析结果显示:锻炼对孕期抑郁呈大效应量干预效果〔SMD=-0.37,95%CI（-0.49,-0.26）,P＜0.00001〕,具有统计学意义。亚组分析结果显示,孕期锻炼开始节点13~27周的干预效果优于孕期28~40、＜12周;≥3次/周的干预效果优于＜3次/周;30~60min/次的干预效果优于＞60min、30min/次;中等强度锻炼的干预效果优于低强度锻炼;8~12周锻炼周期的干预效果优于＞12周、＜8周;锻炼内容对孕期抑郁治疗的干预效果为有氧结合抗阻、瑜伽等。结论 孕期体育锻炼对孕期抑郁治疗有效,不同锻炼内容、强度、频率、周期、开始干预时间节点、单次锻炼时长的锻炼方案干预均有效,且孕期第13~27周开始进行≥3次/周、30~60min/次、8~12周中等强度的体育锻炼方案对孕期抑郁治疗效果更好。     

运动对慢性病干预效果的研究进展

目的 总结运动干预常见慢性病的治疗效果,分析各种运动治疗方案适用范围及存在的问题,以期指导临床实践,并为后续研究提供参考.方法 在WHO官网、Web of Science及相关网站和PubMed、Embase、CNKI、维普、知网、万方等数据库中,以慢性病、运动治疗、干预效果、心脑血管疾病、高血压、...     

头顶一颗珠水煎液对中枢神经系统的影响

目的 观察头顶一颗珠水煎液对小鼠中枢神经系统功能的影响.方法 将50只小鼠随机分为5组,模型组接1g/kg体重腹腔注射氟哌啶醇注射液,头顶一颗株水煎液高、中、低剂量组分别在注射氟哌啶醇的同时,按60、30、10ml/kg剂量腹腔注射头顶一颗株水煎液,对照组注射生理盐水(30 ml/kg),连续用药7d,观察头顶一颗珠水煎液对小鼠学习记忆功能的影响;将40只小鼠随机分为2组,分别腹腔注射头顶一颗珠水煎液(30 ml/kg)和生理盐水(30 ml/kg),连续用药7d后,观察皮下注射5％尼可刹米0.1 ml/10 g后小鼠惊厥发生次数和惊厥发生率;取160只小鼠,进行4项实验,每项实验取40只小鼠随机分为4组,分别腹腔注射头顶一颗珠水煎液(60、30、10 ml/kg)和生理盐水(30ml/kg),连续用药7d后:实验一测定小鼠15 min内的活动次数、实验二观察腹腔注射戊巴比妥钠(40 mg/kg)后小鼠入睡潜伏期和睡眠持续时间的变化、实验三观察腹腔注射0.7％醋酸溶液0.2 ml/10g后,10 min内小鼠扭体反应次数、实验四观察尾悬挂小鼠6 min内累积不动的时间.结果 用头顶一颗珠水煎液处理后的小鼠,自主活动明显受到抑制,能缩短戊巴比妥钠处理后的小鼠入睡潜伏期,延长入睡时间;可减少醋酸致小鼠扭体反应次数;能抑制尼可刹米致惊厥作用;能减少6 min内尾悬挂小鼠活动次数.结论 头顶一颗珠水煎液对中枢神经系统具有明显的抑制作用.     

安徽省大学生体育锻炼与情绪和睡眠状况的相关性研究

研究体育锻炼与大学生的情绪和睡眠状态的相关,为改善大学生心理健康状况提供参考.方法 随机抽取安徽省3所高校556名在校本科生,采用自编体育锻炼调查问卷调查体育锻炼情况,采用匹茨堡睡眠质量指数量表、青少年亚健康多维评定问卷、抑郁自评量表、焦虑自评量表分别调查被试睡眠状况、心身健康和情绪状况.结果 在平时学习的时间花费上,锻炼组与非锻炼组分别为(4.16±2.70),(3.66±2.56)h,差异有统计学意义(P=0.02).锻炼组抑郁自评量表得分明显低于非锻炼组,主观睡眠质量和睡眠潜伏期分量表明显低于非锻炼组,差异均有统计学意义(P值均<0.05).睡眠在体育锻炼对情绪状态的预测中起到部分中介作用.结论 体育锻炼越积极的大学生情绪和睡眠状况越好.体育锻炼干预可通过影响睡眠对情绪产生积极的影响.