医疗照射剂量水平及其防护

本文讨论了医疗照射的频度、剂量水平和防护问题。诊断X线检查频度在发达国家为每年每千人300—900人次,在发展中国家为100—200人次/千人·年,我国为124.5人次/千人·年;平均有效剂量当量在发达国家为1mSv/年·人,全世界平均值为0.4mSv/年·人,我国为 0.5mSv/年·人;医疗照射所致超额死亡率在发达国家估计为10—15/百万人,我国为4.27/百万人。 我国的诊断X线检查频度和剂量水平将进一步增长,为减少医疗照射,我们必须采取预防措施。     

Occupational chronic exposure to metals

Summary Stainless steel welders (n = 103) were examined. To estimate external exposure, personal air sampling was used. Internal exposure was quantified by the determination of nickel levels in erythrocytes, plasma and urine. Men and women (n = 123) were examined for control purposes. In the plasma and erythrocytes of the controls the nickel concentration was below the level of detection (< 1.81 μg/l). The element concentrations in urine were between < 0.1 and 13.3 μg/l. Of the controls 95% showed nickel levels in urine below 2.2 μg/l (reference value). The average concentration of nickel in the air was 93 ± 81 μg/m³. The average concentration of nickel in the plasma samples was 4.9 ± 4.0 μg/l (95th percentile 12.8 μg/L). In erythrocytes nickel could not be detected. The nickel concentrations in the urine of the welders were 18.5 ± 28.5 μg/l on average (95th percentile 52.5 μg/l). Only a weak correlation between the nickel levels of plasma and urine could be detected (C_urine = 2.07 + 8.45 C_plasma; r = 0.294; p < 0.01). Based on our results and on the reported literature a future limit value for the nickel concentration in urine should lay between 30 and 50 μg/l. This value corresponds to an external exposure of 500 μg nickel per cubic metre.     

Cardiovascular malformations and organic solvent exposure during pregnancy in Finland

In order to investigate the possible association between cardiovascular malformations and maternal exposure to organic solvents during the first trimester of pregnancy, 569 cases and 1,052 controls were retrospectively studied. The cases represented all infants with diagnosed cardiovascular malformations born in Finland in 1982-1984, and the controls were randomly selected from all normal births in the country during the same period. All mothers were interviewed approximately 3 months after delivery by a midwife using a structured questionnaire. Exposures to organic solvents at work during the first trimester of pregnancy were slightly more prevalent among the mothers of affected infants (10.4%) than among those of controls (7.8%). Logistic regression analysis of exposure to organic solvents showed an adjusted relative odds ratio of 1.3 (95% confidence interval, 0.8-2.2). In the analysis of ventricular septal defect, exposure to organic solvents showed an adjusted relative odds ratio of 1.5 (95% confidence interval, 1.0-3.7).     

噪声对耳蜗外淋巴中某些离子含量的影响

将１８只豚鼠分为１个对照组和２个暴露组，分别暴露于１１５ｄＢ（ＳＰＬ）、１２５ｄＢ（ＳＰＬ），１．５ｋＨｚ纯音０．５ｈ，以皮层听区诱发电位为检查指标，观察暴露前后动物听力的改变，并测定了耳蜗外淋巴中Ｎａ＋、Ｋ＋、Ｃａ２＋、Ｍｇ２＋离子含量的变化。结果表明，声暴露后各组动物听阈明显提高，且１２５ｄＢ组听力损失明显高于１１５ｄＢ组。１２５ｄＢ声暴露后，耳蜗外淋巴中Ｃａ２＋明显降低，而１１５ｄＢ组与正常对照组相比差异无显著性。声暴露对其它离子的含量没有影响。结果提示Ｃａ２＋可能与声损伤，特别是与永久性听力损失有关。     

Parenchymal and pleural fibrosis in construction workers.

Exposure to mineral dust was studied among construction workers (N = 437) with the aid of a questionnaire and a chest X-ray examination of the lungs. The results of the questionnaire showed that 81% of the construction workers had been exposed to asbestos. Exposure had occurred in all of the occupational groups studied. Pleural plaques and/or lung fibrosis (ILO greater than or equal to 1/1) were found in 26% of the examined workers; the prevalence varied from 18 to 40% among the various occupational groups. Comparison with a representative sample of the Finnish male population from another investigation indicates that the frequency of lung fibrosis (ILO greater than or equal to 1/1) is at least two times higher among the examined construction workers than among the general population. It seems likely that exposure to asbestos dust can be considered an etiological factor for an appreciable number of the X-ray findings.     

Usefulness of erythrocyte protoporphyrin as a primary screening test for lead exposure in children

Erythrocyte protoporphyrin and blood lead concentrations were measured in samples from 583 Saudi children attending the outpatient clinics. Erythrocyte protoporphyrin concentrations showed poor correlation with blood lead concentrations of 25 ug dl^?1 and below. Measurement of erythrocyte protoporphyrin as a primary test for lead exposure is not recommended.     

Subclinical neurotoxicity of mercury vapor revealed by a multimodality evoked potential study of chloralkali workers

Pattern visual, brainstem auditory, and somatosensory evoked potential (EP) studies were performed on 26 chloralkali workers. The intensity of mercury vapor exposure in these workers was estimated from the individual working history. Mercury levels in blood, urine, and hair were determined with atomic absorption spectrometry. The EP findings were compared with those from individually matched normal subjects. In brainstem auditory and somatosensory EP studies, prolonged neural conduction times in the central nervous system (CNS) were found in workers exposed to mercury vapor. In the pattern visual EP study, mercury workers had higher interpeak amplitudes. Findings of this study suggested that chronic exposure to mercury vapor would affect the CNS functions. A multimodality EP study is a useful adjunct in evaluation of chronic mercury neurotoxicity, especially in an epidemiological study.     

Rounded atelectasis: diagnosis by fine-needle aspiration cytology.

Rounded atelectasis, a rare, benign mass lesion, is most often seen in association with asbestos-related pleural changes. Often a presumptive diagnosis can be made on the basis of characteristic CT and chest radiographic findings. However, not infrequently radiographic imaging fails to differentiate rounded atelectasis from primary bronchogenic carcinoma, a disease which is seen with increased frequency in patients with asbestos exposure. We describe two cases where the diagnosis of rounded atelectasis was made by fine-needle aspiration (FNA) cytology. The cytologic features included abundant pulmonary parenchymal material with thickened alveolar walls containing pulmonary macrophages and connective tissue. It is important to realize that this is a useful positive finding indicating rounded atelectasis, rather than a negative finding suggesting the absence of neoplasm. Needles with a cutting action may be necessary to obtain sufficient material to make the diagnosis of rounded atelectasis.