实习生职业接触噪声与听力损伤研究

整群抽样调查广州空调行业技校、职业中等中专技术学校男性实习生1年实习期噪声性听力损伤情况。调查的作业环境噪声强度超标率平均为44．3％,实习生的高频听力损伤检出率平均为31．3％,且随接触噪声强度的增加而升高。脱离噪声作业环境1个月后复查,仍为高频听损者占复查者的47．4％。提示实习试用期的噪声接触可致实习生听力损伤,实习期的职业危害防治不容忽视。     

铸造工肺通气功能动态观察

为探讨长期铸造作业对工人肺通气功能的影响 ,选择 1993～ 1999年间从事铸造作业的工人 2 18人为观察组 ,以不接触职业危害因素的生产工人 10 4名为对照组 ,每 3年进行 1次职业健康检查 ,共查 3次 ,对两组工人肺通气功能进行动态观察、比较。结果观察组肺通气功能在各年间明显低于对照组 (P <0 . 0 1) ;随接尘时间的延长 ,观察组肺通气功能 (除FEV1%外 )逐年显著下降 (P <0 . 0 5 )。提示长期从事铸造作业可对工人的肺通气功能造成明显损害。     

γ射线诱发培养淋巴细胞TCR基因突变的剂量-效应关系

目的　探讨γ射线诱发培养淋巴细胞T细胞受体 (TCR)基因突变的剂量 效应关系。方法　以不同剂量 (0～ 4 0Gy)的γ射线照射新鲜分离的健康成人外周血淋巴细胞 ,植物血凝素脉冲式刺激 2h后 ,用白细胞介素- 2培养 7d ,用单克隆抗体直接免疫荧光标记流式细胞术检测TCR基因突变频率 (TCRMF)。应用SAS统计软件包编写的程序进行辐射剂量 效应曲线的拟合和筛选。结果　培养 7d后 ,TCRMF (10 -4)随照射剂量D (Gy)的增加而增高 ,最佳拟合曲线为二次多项式模型 ,其方程式可描述为 :TCRMF =2 . 74+ 6. 0 5D + 7 60D2 (F =3 62. 3 7 16,P <0 . 0 1,经校正的R2 =0 . 9999)。结论　TCR基因突变作为一种有潜力的生物剂量计可能用于近期辐射照射生物剂量的估算。     

Self-Report Measure of Low Back-Related Biomechanical Exposures: Clinical Validation

Low back pain and symptoms are major contributors to ambulatory visits, economic burden, and reduced readiness among military personnel and employers in the civilian workplace as well. While a link between low back pain and biomechanical exposures has been established, efficient surveillance methods of such exposures are still needed. Furthermore, the utility of self-report measures for biomechanical exposures has not been examined extensively. The present cross-sectional study analyzed questionnaire data from US Army soldiers (n = 279) working in previously identified occupational specialties that were associated with high risk for low back pain and/or low back pain disability. Demographic characteristics, physical workload, health behaviors, and psychosocial factors were assessed in addition to self-reported workplace biomechanical exposures using the Job Related Physical Demands (JRPDs). Outcomes included self-reported low back pain severity, low back symptoms, functional limitations, and general physical health. The results indicated that the self-report measure of biomechanical exposure had a high degree of internal consistency (Cronbach alpha, 0.95). The JRPD index correlated with low back symptoms, pain intensity, function, and perceived work load using the Borg scale. Regression analyses indicated statistically significant associations between the JRPD and back pain specific pain severity and physical function, but not for general physical health (SF-12) after controlling for age, gender, educational level, job type, and reported exercise and work stress. Specifically, higher JRPD scores (representing greater biomechanical exposure) were associated with higher levels of pain intensity and functional limitations. Higher JRPD scores were found to place an individual at a greater likelihood for being a case with low back pain within the past 12 months (OR = 1.01 per point increase in scale-95%; range 38–152; CI = 1.00–1.02, p 0.05). While future longitudinal studies of the JRPD determining the predictive validity of the measure are needed, the present study provides evidence of the utility of the JRPD for assessing biomechanical exposures associated with low back pain within high-risk jobs. The findings suggest that the JRPD may assist with surveillance efforts and be useful as a process and/or outcome measure in research related to occupational rehabilitation.     

Laboratory exposures to brucellae and implications for bioterrorism

Brucellae are class 3 organisms and potential agents of bioterrorism. Because of effective public health measures, brucellosis has become a rare disease in industrialized countries, and clinical microbiology laboratories are frequently unfamiliar with the genus. A low index of suspicion by physicians or failure to notify the laboratory, equivocal Gram-stain results, misidentification of the organism by commercial systems, unsafe laboratory practices, and laboratory accidents have been responsible for numerous cases of exposure to the organism and laboratory-acquired disease in recent years. Discovery of a laboratory exposure to brucellae should prompt an exhaustive investigation of the event and its circumstances, definition of the population at risk, enforcement of safe laboratory practices, and antimicrobial drug prophylaxis for exposed persons. Inadvertent exposures to brucellae in the clinical laboratory indicate a widespread lack of preparedness to cope with eventual biologic threats involving use of the organism.     

Operating room nitrous oxide trace concentrations: a clinical study in ambulatory surgery

Purpose:

This blinded study evaluates the N₂O concentration variations in an ambulatory surgery centre using a small, simple on-line trace gas concentration monitor (GasFinder™ [Medair AB, Delsbo, Sweden]).

Scope:

Thirty-seven day surgical sessions using standardised anaesthesia with propofol/fentanyl induction and sevoflurane/N₂O with larynx mask. Five of 37 time-weighted averages (TWA) were greater than 25 ppm but less than 100. Peak registered concentrations reached 2000 ppm. Eleven sessions showed peak values higher than 100 ppm (range 13-1693).

Conclusions:

This simple, on-line N₂O monitor is a useful tool for detecting deviations from strict gas hygiene.     

Risk of silicosis in cohorts of Chinese tin and tungsten miners, and pottery workers (I): an epidemiological study

BACKGROUND: Epidemiological evaluations of the risk of silicosis in relation to exposure to crystalline silica have raised the question of whether different types of silica dust exposures vary with respect to their ability to cause silicosis. The aim of this study is to compare the risk of silicosis among cohorts of silica dust-exposed Chinese tin miners, tungsten miners, and pottery workers and to assess whether gravimetric measurements of respirable silica dust sufficiently determine the risk of silicosis or whether other factors of exposure may play a significant role. METHODS: Cohorts were selected from 20 Chinese mines and potteries. Inclusion criteria were starting employment after January 1, 1950 and being employed for at least 1 year during 1960-1974 in one of the selected workplaces. Radiological follow-up for silicosis onset was from January 1, 1950 through December 31, 1994. Silicosis was assessed according to the Chinese radiological criteria for diagnosis of pneumoconiosis (as suspect, Stage I, II, or III). Exposure-response relationships were estimated for silicosis of Stage I or higher. Silica dust exposure was estimated in terms of cumulative total dust exposure, calculated from a workplace, job title, and calendar year exposure matrix, and individual occupational histories. Cumulative total dust exposure was converted in two steps into cumulative respirable dust exposure and cumulative respirable silica dust exposure using conversion factors estimated from side-by-side measurements conducted in 1988-89. RESULTS: The male cohorts included 4,028 tin miners, 14,427 tungsten miners, and 4,547 pottery workers who had similar onset of employment and duration of follow-up. For a given exposure level, the risk of silicosis was higher for the tin and tungsten than the pottery workers. CONCLUSION: The observed differences in the risk of silicosis among the three cohorts suggest that silica dust characteristics, in addition to cumulative respirable silica dust exposure, may affect the risk of silicosis.     

Radiation exposure from work-related medical X-rays at the Portsmouth Naval Shipyard

BACKGROUND: Previous analyses suggest that worker radiation dose may be significantly increased by routine occupational X-ray examinations. Medical exposures are investigated for 570 civilian workers employed at the Portsmouth Naval Shipyard (PNS) at Kittery, Maine. The research objective was to determine the radiation exposure contribution of work-related chest X-rays (WRX) relative to conventional workplace radiation sources. METHODS: Methods were developed to estimate absorbed doses to the active (hematopoietic) bone marrow from X-ray examinations and workplace exposures using data extracted from worker dosimetry records (8,468) and health records (2,453). Dose distributions were examined for radiation and non-radiation workers. RESULTS: Photofluorographic chest examinations resulted in 82% of the dose from medical sources. Radiation workers received 26% of their collective dose from WRX and received 66% more WRX exposure than non-radiation workers. CONCLUSIONS: WRX can result in a significant fraction of the total dose, especially for radiation workers who were more likely to be subjected to routine medical monitoring. Omission of WRX from the total dose is a likely source of bias that can lead to dose category misclassification and may skew the epidemiologic dose-response assessment for cancers induced by the workplace.     

Porcine skin ED50 damage thresholds for 2,000 nm laser irradiation

BACKGROUND AND OBJECTIVES: To gain refinement in safe-exposure limits, indicated by the maximum permissible exposure (MPE) limits, the minimum visible lesion thresholds for three spot sizes (5-15 mm) and four exposure durations (0.25-2.5 seconds) were determined for the skin at 2,000 nm continuous wave laser irradiation. STUDY DESIGN/MATERIALS AND METHODS: A series of experiments were conducted in vivo on female Yucatan mini-pigs to determine the ED50 damage thresholds for 2,000 nm continuous wave laser irradiation. The study employed Gaussian laser beam exposures with spot diameters (1/e2) of 4.83, 9.65, and 14.65 mm and exposure durations of 0.25, 0.5, 1.0, and 2.5 seconds as a function of laser power. The effect of each irradiation was evaluated within 1 minute after irradiation and the final determination was made at 48 hours post-exposure. Probit analysis was conducted to estimate the dose for 50% probability of laser-induced damage (ED50), defined as persistent redness at the site of irradiation for the mini-pig skin after 48 hours. RESULTS: The MPE spot size and exposure duration trends for 2,000 nm laser exposure is consistent for exposure diameters less than 3.5 mm. However, for larger exposure diameters of 4.83, 9.65, and 14.65 mm and exposure duration longer than 0.25 second, the current MPEs are bigger than one tenth of our damage thresholds. For Gaussian laser profile, which is common for many laser output irradiance distributions, lower energy is required to generate a lesion on skin for smaller spot sizes and shorter exposure duration. On the other hand, for spot sizes greater than 4.83 mm and exposure duration over 0.25 second, the average radiant exposure at threshold is inversely proportional to spot size. The irradiance-time and temperature-time power law at the threshold were investigated as well and showed that the irradiance-time power law was a close approximation to estimate laser irradiance at ED50 damage threshold. CONCLUSIONS: The thresholds study shows that consideration for lowering the MPE standards should be explored as the laser beam diameter becomes larger than 3.5 mm. Based on the limited experimental data, the duration and size dependences of the ED50 damage thresholds could be described by an empirical equation: Irradiance at the threshold = (5.669-1.81xspot diameter)xexposure duration -0.794.     

Factor structure of the pain disability index in workers compensation claimants with low back injuries

OBJECTIVE: To examine the factor structure of a telephone-administered Pain Disability Index (PDI) and the effects of race and sex on the PDI. DESIGN: Computer-assisted telephone interviews of a cohort with occupational low back injuries. SETTING: General community. PARTICIPANTS: Missouri workers compensation claimants (N=1329) with low back injuries. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: PDI, levels of pain severity, Social Security Disability Insurance status, and the Fear-Avoidance Behavior Questionnaire. RESULTS: Results for the total sample and by race/sex group indicated support for a 2-factor model of the PDI corresponding to voluntary activities (eg, social, occupational, recreational) and obligatory activities (eg, activities of daily living, eating, sleeping). Additional psychometric analyses of the voluntary and obligatory subscales indicated adequate reliability and construct validity overall and in each of the race/sex groups. African Americans reported more pain-related disability on both subscales than whites. Women reported more disability on the voluntary subscale than men. CONCLUSIONS: The results support use of the PDI as a bidimensional measure of pain-related disability, with strong psychometric properties. They also support its administration by telephone.