电磁场的生物效应的研究现状与展望

随着科学技术的进步,人们越来越多的暴露于各种电磁场中,电磁场的生物效应研究也随之成为热点。但由于这些研究手法、对象以及研究条件各不相同,有很多的研究结果并不完全一致,有较多的不确定因素在里面。本文为了分析电磁场的生物效应．综述了近几年来电磁生物效应的研究进展,列举了不同类型电磁波对细胞昕产生的生物效应,并对其进行了分析和总结,最后结合这些进展以及细胞信息学等相关知识,提出了电磁生物效应的一些假设和前景展望,并提出了将膜片钳技术应用于电磁场生物效应研究的可行性以及中高频电磁效应研究的必要性？     

Derivation of numerical values for the World Health Organization guidelines for recreational waters

In April 2001, draft ‘Guidelines’ for safe recreational water environments were developed at a World Health Organization (WHO) expert consultation. Later the same month, these were presented and discussed at the ‘Green Week’ in Brussels alongside the on-going revision of the European Union Bathing Water Directive 76/160/EEC. The WHO Guidelines cover general aspects of recreational water management as well as define water quality criteria for various hazards. For faecal pollution, these include faecal indicator organism concentrations and an assessment of vulnerability to faecal contamination. Central to the approach set out in the WHO Guidelines are: (i) the concept of beach profiling to produce a ‘sanitary inspection category’ which implies a priori hazard assessment as a core management tool and (ii) the prediction of poor water quality to assist in real time risk assessment and public health protection. These management approaches reflect a harmonized approach towards the assessment and management of risk for water-related infectious disease being applied by WHO. Numerical microbiological criteria for intestinal enterococci are proposed in the new Guidelines. These were developed using a novel approach to disease burden assessment, which has been applied to both recreational waters and urban air quality. This paper explains the scientific rationale and mathematical basis of the new approach, which is not presented in the WHO Guidelines for recreational waters.     

Modelling air pollution for epidemiologic research — Part I: A novel approach combining land use regression and air dispersion

A common limitation of epidemiological studies on health effects of air pollution is the quality of exposure data available for study participants. Exposure data derived from urban monitoring networks is usually not adequately representative of the spatial variation of pollutants, while personal monitoring campaigns are often not feasible, due to time and cost restrictions. Therefore, many studies now rely on empirical modelling techniques, such as land use regression (LUR), to estimate pollution exposure. However, LUR still requires a quantity of specifically measured data to develop a model, which is usually derived from a dedicated monitoring campaign. A dedicated air dispersion modelling exercise is also possible but is similarly resource and data intensive.This study adopted a novel approach to LUR, which utilised existing data from an air dispersion model rather than monitored data. There are several advantages to such an approach such as a larger number of sites to develop the LUR model compared to monitored data. Furthermore, through this approach the LUR model can be adapted to predict temporal variation as well as spatial variation. The aim of this study was to develop two LUR models for an epidemiologic study based in Greater Manchester by using modelled NO₂ and PM₁₀ concentrations as dependent variables, and traffic intensity, emissions, land use and physical geography as potential predictor variables. The LUR models were validated through a set aside “validation” dataset and data from monitoring stations.The final models for PM₁₀ and NO₂ comprised nine and eight predictor variables respectively and had determination coefficients (R²) of 0.71 (PM₁₀: Adj. R² = 0.70, F = 54.89, p < 0.001, NO₂: Adj. R² = 0.70, F = 62.04, p < 0.001). Validation of the models using the validation data and measured data showed that the R² decreases compared to the final models, except for NO₂ validation in the measured data (validation data: PM₁₀: R² = 0.33, NO₂: R² = 0.62; measured data: PM₁₀: R² = 0.56, NO₂: R² = 0.86). The validation further showed low mean prediction errors and root mean squared errors for both models.     

Effect of maternal manganese blood levels on erythrocyte calcium-pump activity in newborns

Manganese (Mn) is widely distributed in the biosphere but occurs in only trace amounts in animal tissues. Although Mn deficiency and toxicity both have pathological consequences, the underlying biochemical lesions have not been well defined. In vitro studies suggest that transport proteins are affected by Mn, lead (Pb), and selenium (Se). Among these transport proteins, the calmodulin-regulated calcium pump (Ca(2+)Mg(2+)ATPase) could be inhibited by Mn. In order to understand Mn biochemical pathways, we examined the relationships between Mn blood levels and red blood cell Ca-pump activity among 248 mothers and newborns, environmentally exposed to Mn, Pb, and Se. POPULATION AND METHODS: 248 mother-newborn pairs were recruited at Robert Debré University Hospital (Paris). Blood Mn and Pb concentrations were measured by absorption spectrophotometry. Se was measured by fluorometric method. Red blood cell membrane suspensions were obtained for Ca-pump activity measurements. Linear and quadratic regression models and Pearson correlation were performed. RESULTS: A non-linear parabolic relationship between maternal Mn blood levels and newborn Ca-pump activity was discovered from the analysis of the observed data. The peak level of maternal Mn that corresponded to a maximal activity of the newborn Ca-pump was estimated at 23.9 microg/l with a 95% confidence interval of 17.6 to 32.4 microg/l. An inhibition of this enzyme was observed at low and high levels of maternal Mn. The relationships between the newborn Ca-pump activity and maternal Se and Pb levels became non-significant after adjustment on all the co-factors included in the final model. CONCLUSION: Maternal environmental exposure to Mn, as reflected by maternal blood levels of this metal, is associated with a reduced activity of newborn erythrocyte Ca-pump in a non-linear pattern. Mn levels between 17.6 and 32.4 microg/l in maternal blood probably correspond to the optimal physiological concentration for the metabolism of this enzyme in newborns.     

ENERGY REQUIREMENTS OE PRACTICAL JOBS FROM PULSE INCREASE AND ERGOMETER TEST

Abstract

The purpose of this study was to determine whether the angle of the knee joint has an effect on the Fitness Index Scores of the HST. Thirty-three young Caucasoid male subjects were used in this study. The HST was administered in four different knee-joint angles. A repeated measures one-way classification analysis of variance, a one-way classification analysis of variance and an analysis of covariance were used to analyse the data obtained during nine weeks. All tests yielded significant F ratios at the 0·01 level of confidence. Based on these findings, persons who perform the HST in different knee-joint angles have indices which are not measuring cardiopulmonary stress on the same scale. The HST based on standardization of the knee-joint angle promises to increase the evaluating or discriminating power of the test.     

Size distribution of airborne particles controls outcome of epidemiological studies

Epidemiological studies typically using wide size range mass metrics (e.g. PM₁₀) have demonstrated associations between airborne particulate matter and several adverse health outcomes. This approach ignores the fact that mass concentration may not correlate with regional lung dose, unlike the case of trace gases. When using measured particle size distributions as the basis for calculating regional lung dose, PM₁₀ mass concentration is found to be a good predictor of the mass dose in all regions of the lung, but is far less predictive of the surface area and particle number dose. On the other hand, measurements of particle number do not well predict mass dose, indicating that the chosen particle metric is likely to determine the health outcomes detectable by an epidemiological study. Consequently, epidemiological studies using mass metrics (PM_2.5 and PM₁₀) may fail to recognise important health consequences of particulate matter exposure, leading to an underestimate of the public health consequences of particle exposure.     

A two-step medically based injury surveillance system--experiences from the Oslo injury register

This paper presents a two-step injury surveillance system. In the first step, limited data (a minimum data set) on all (or a representative sample of all) injuries to residents and non-residents within a defined geographical area were obtained using routine collection procedures within the medical care system. The second step involved periodically sampling of specific injuries, injured persons, or places for in-depth investigations from the database established by the first step, or selecting relevant injured persons seeking treatment in the medical care system, to collect many data (an expanded data set) on a limited number of injuries. This system was implemented in Oslo. Data from about 48,000 injuries were collected annually. Two in-depth investigations of serious occupational injuries were carried out. The first involved 223 cases and the second, 50 cases. Some in-site studies were included. Experiences from the implementation in Oslo suggest that this system can function in the medical care system and provide data required for making estimates of injury incidence rates, establishing trends, and on contributing factors to injuries. A crucial factor in the success of the first part of such a system is to have enough resources for continuous quality control and feedback to personnel involved in the registration of data. Combining the registered data from general practitioners, accident and emergency departments, hospitals and notifications of fatalities in Oslo, and on assessments of the number of injuries treated by private clinics and occupational health centres in Oslo, and in the health care system outside of Oslo, leads to the conclusion that 11.9% of the residents of Oslo will annually be treated for an injury.     

Factors influencing worker use of personal protective eyewear

Objective

To identify and describe the array of factors that influence a workers’ decision to wear personal protective eyewear (PPE) and the barriers that exist in preventing their use.

Design, setting and participants

A series of focus groups enrolled workers and supervisors primarily from manufacturing, construction, or service/retail industries that had potential exposure to eye injury hazards in their job tasks. Focus group sessions were facilitated to collect qualitative and quantitative data in two categories, “sought information” and “emergent themes”, related to the factors influencing use of PPE.

Results

We conducted a series of 7 groups with 51 participants, 36 (71%) males and 15 (29%) females ranging in age from 19 to 64 years old, from a variety of occupations including construction (24%), production (22%), installation, repair and maintenance (14%), and healthcare (10%). Most were highly experienced in their occupation (>10 years); males (86%) and females (53%), and had received some safety training in the past (82%). The majority of workers in this study were required to wear PPE on their worksite (78%), however only 55% had a dedicated safety officer. A conceptual model that summarizes the “sought information” and “emergent themes” is presented that depicts the decision making process for the factors influencing use of PPE and consists of three primary branches; perceptions of hazards and risks, “barriers” to PPE usage, and enforcement and reinforcement. Lack of comfort/fit, and fogging and scratching of the eyewear were suggested as the most important barriers to PPE usage. Younger age and lack of safety training were other important factors affecting use of PPE.

Conclusions

Several potentially modifiable factors identified would lead to an increase in workers’ PPE use and encourage supervisors to provide ongoing positive feedback on the continuous use of PPE by workers at risk for an eye injury.     

The Hispanic Americans Baseline Alcohol Survey (HABLAS): Rates and predictors of DUI across Hispanic national groups

This paper examines rates of self-reported driving under the influence (DUI) of alcohol and 12-month and lifetime DUI arrest rates among Mexican Americans, Puerto Ricans, Cuban Americans and South/Central Americans in the U.S. population. Using a multistage cluster sample design, a total of 5224 individuals 18 years of age and older were selected from the household population in five metropolitan areas of the U.S.: Miami, New York, Philadelphia, Houston and Los Angeles. The survey weighted response rate was 76%. Among men, 21% of Mexican Americans, 19.9% of South/Central Americans, 11.6% of Puerto Ricans and 6.9% of Cuban Americans reported DUI. Rates were lower among women, ranging from 9.7% for Mexican Americans to 1.3% for Cuban Americans. Mexican American men had the highest 12-month arrest rate (1.6%) and the highest lifetime arrest rate (11.2%). Drinkers who reported DUI were heavier drinkers than those not reporting DUI according to a variety of indicators. However, most DUI incidents involved non-alcohol-dependent drivers. Mexican Americans and South Central/Americans, men, younger drivers, those with less than high school education, those with higher income and higher alcohol consumption were more likely to report DUI and DUI arrests. These findings show that Hispanic national groups in the U.S. are diverse regarding drinking and DUI-related experiences.