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.     

低剂量甲基汞在小鼠体内分布及其对细胞周期进程的影响

连续９０天饮用含甲基汞浓度为１／１０００ＬＤ５０、１／１００ＬＤ５０、１／５０ＬＤ５０和１／１０ＬＤ５０的自来水的雄性昆明小鼠，各脏器中总汞含量均高于对照组（Ｐ＜０．０５～０．００５），并且随着染毒剂量增加，脏器中总汞含量也随之增高。同时采用ＦＡＣＳｃａｎ流式细胞仪和“ＣｅｌｌＦＩＴ”软件分析脾细胞周期进程，发现除１／１０００ＬＤ５０剂量组外，其余各剂量组从Ｇｏ／Ｇ１时相进入Ｓ时相的脾细胞百分数均明显高于对照组（Ｐ＜０．０５），与染毒剂量呈明显正相关。表明连续经口摄入低剂量甲基汞小鼠脾细胞周期进程加快，细胞ＤＮＡ复制增强。     

Cardiovascular malformations, work attendance, and occupational exposures during pregnancy in Finland

To explore for associations between occupational factors and cardiovascular malformations, information on the parents of 160 infants with cardiovascular malformations and 160 control parents was studied. The case infants had been reported consecutively to the Finnish Register of Congenital Malformations. All mothers were interviewed identically after delivery, using both open and pro forma questions about detailed work tasks, exposures, and leisure activities during pregnancy. The interview information was evaluated blindly. Neither parental occupational titles nor maternal working per se gave new clues to the teratogenic risk; nor did shift working, wearing of personal protective equipment, or the mother's own opinion on exposures during pregnancy. Identified occupational exposures, as categorized by an industrial hygienist, showed no remarkable associations to cardiovascular malformations. Few mothers were exposed substantially to specific occupational hazards. Comparing mothers who used medications in the first trimester with those who did not showed an odds ratio of 2.2 (95% confidence interval 1.3-3.9) when adjusted for potential confounding by multivariate logistic methods.     

A prospective study of allergy development in 158 children and 128 adults with new extensive exposure to furred animals

BACKGROUND: There is still controversy over whether exposure to furred animals increases or decreases the risk of developing sensitization and allergic symptoms to such animals, and there is a need for further knowledge on this subject. OBJECTIVE: The aim of this study was to follow allergy development in relation to new extensive exposure to furred animals in adults and children. METHODS: A total of 286 individuals, 128 parents and 158 children, were recruited from 68 families who intended to buy a dog or a cat, or where one child of the family intended to start riding a horse. Subjects were examined before the new allergen exposure and once a year thereafter for 5 years, in all at six occasions, and they also completed questionnaires covering allergy symptoms. Serum IgE antibodies to cat, dog and horse were determined each year, and fur allergens from beds and living rooms were analysed. RESULTS: Two-hundred and fifty-six study subjects remained for evaluation, 37 of whom showed signs of allergic sensitization at the start of the study. Four children (11%) in this pre-sensitized group developed IgE antibodies to their new animal and six (16%) to another animal. Among the 219 participants who were not sensitized when entering the study, one male adult (0.4%) developed a sensitization to his new animal, and nobody developed sensitization to other animals. Pre-sensitized individuals had significantly more allergic symptoms at the study start, but the symptom scores did not change over time. CONCLUSIONS: When the first year of a human's life has passed, we have no strong evidence to recommend avoidance of a domestic animal in order to prevent new allergy development, even if there are known allergies in the family or if the individual is sensitized and has allergic symptoms to another allergen. Five years exposure to new fur allergens does not seem to influence sensitization to these animals in either sensitized or non-sensitized children and adults.     

外伤性视神经病变的临床治疗分析

目的　探讨大剂量甲基强的松龙冲击疗法治疗外伤性视神经病变的疗效。方法　 2 0例 (2 0只眼 )外伤性视神经病变患者为治疗组 ,应用大剂量甲基强的松龙冲击治疗 ,另 2 0例 (2 0只眼 )外伤性视神经病变患者为对照组 ,使用常规剂量的地塞米松治疗。两组均同时使用高渗剂、血管扩张剂、神经营养剂及 B族维生素治疗 ,对两组病例药物治疗的结果进行总结分析。结果　治疗组经治疗后视力开始恢复的时间早于对照组 ,治疗组的总有效率为 80 % ,对照组的总有效率为 6 0 % ,治疗组的疗效优于对照组 ,且治疗越早疗效越好。两组比较具有显著的统计学差异 (P <0 .0 5 )。结论　大剂量甲基强的松龙冲击疗法治疗外伤性视神经病变疗效显著 ,治疗方便 ,是较理想的治疗方法     

Assessment of hand-arm vibration exposure among traffic police motorcyclists

 The aims of this study were (1) to evaluate subjective symptoms in the hand-arm system of all traffic police motorcyclists of a city located in the central part of Japan and (2) to assess their hand-arm vibration exposure associated with traffic police motorcycle riding. The study population consisted of 119 motorcycling traffic policemen and 49 male controls. By means of a questionnaire, information on the occupational history and the presence of subjective symptoms in the hand-arm system of all subjects was obtained. Vibration was measured on the handlebars of the representative motorcycles and on the hands of the riders. The 4- and 8-h energy-equivalent frequency-weighted acceleration as well as the lifetime vibration dose were calculated for all police motorcyclists. The prevalence of finger blanching in the traffic police motorcyclists was 4.2%, but none of the controls had this symptom. The rates of finger numbness (19.3%), finger stiffness (16.0%), shoulder pain (13.4%), and shoulder stiffness (45.4%) were significantly higher among police motorcyclists as compared with controls. The root-mean-square (rms) frequency-weighted acceleration on the handlebars of police motorcycles was in the range of 2.2–4.9 m/s² rms. The computed 4- and 8-h energy-equivalent frequency-weighted acceleration values were 2.8– 4.5 and 2.0 –3.2 m/s² rms, respectively. A pattern of increasing percentage prevalence with increasing cumulative vibration dose was noticed. The subjects with a lifetime vibration dose of more than 20.1 m² h ³ s^-4 (ln scale) showed significantly higher prevalence rates for symptoms in the fingers and shoulders as compared with the control group. As occupational vibration exposure of traffic police motorcyclists might be considered a risk factor for the development of symptoms in the hand-arm system of the riders, its evaluation and control is needed for prevention methodology evolution. Received: 15 April 1996/Accepted: 8 November 1996     

Cocaine tolerance: Interactions among random-ratio and random-interval reinforcement-schedule parameters and repeated exposure to cocaine

Food-deprived pigeons were trained to peck a key under either a three-component multiple random-ratio 5, random-ratio 25, random-ratio 125 schedule or a three-component multiple random-interval 10-sec, random-interval 30-sec, random-interval 125-sec schedule of food presentation. Following determination of acute effects of cocaine (1.0-13.0 mg/kg), are-sponse-rate-reducing dose was given before each daily session. Once performance under conditions of daily administration had become stable, other doses occasionally were substituted for the usual daily dose so that dose effects could be assessed. Tolerance, i.e., a rightward shift in the dose-effect curve was observed in all subjects. For subjects studied under the random-ratio schedules, however, the robustness of the tolerance usually was related to the schedule-parameter value; tolerance was great at lower random values. By contrast, subjects whose responding was maintained by random-interval schedules were less likely to show tolerance that was schedule-parameter dependent. The results also provide suggestive evidence that dose may be an important factor in determining effects of repeated cocaine exposure; repeated administration of larger doses may be less likely to result in tolerance than similar exposure to smaller doses.     

Adenovirus-mediated human β-nerve growth factor gene transfer has a protective effect on cochlear spiral ganglion after blast exposure

Objective：To study whether adenovirus-mediated human β-nerve growth factor （Ad-hNGFβ） gene has any protective effect on blast hearing impairment. Methods：Deafness was induced by blast exposure （172.0 dB） in 30 healthy guinea pigs. On day 7 of blast exposure, Ad-hNGFβ was infused into the perilymphatic space of 20 animals as the study group （hNGFβ group）, and artificial perilymph fluid （APF） was infused into the perilymphatic space of the other 10 animals as the control group. At weeks 1, 4 and 8 after blast exposure, the animals were sacrificed and the cochleae were removed for immunohistochemical and HE stainings. Results： Expression of Ad-hNGFβ protein was detected in each turn of the cochlea at the 1st week, with almost equal intensity in all turns. At the 4th week, the reactive intensity of the expression of Ad-hNGFβ protein decreased. At the 8th week, no expression was detectable. The results of HE staining showed that the amount of spiral ganglions in hNGFβ group was significantly greater than that of the control group at week 4 （P〈0.01）. Conclusion： Ad-hNGFβ can be expressed at a high level and for a relatively long period in the blast impaired cochlea, suggesting that Ad-hNGFβ has a protective effect on cochlear spiral ganglion cells after blast exposure and the efficient gene transfer into cochlea had been achieved without toxicity.     

Effects of occupational exposure and smoking on respiratory symptomatology and PFT in healthy panelists and COPD patients

A panel of 377 healthy adults and 920 COPD patients aged 30–65 years, is annually interviewed (ATS-NHLI health questionnaire) and performs pulmonary function test (PFT), which includes: FVC, FEVI, FEVl/FVC, PEF, FEF50 and FEF75. Baseline data analysis showed a more significant excess in respiratory symptmos (8.8% to 21.4%) and lower PFT (2.4% to 8.0%) among patients occupationally exposed to dust, than among healthy exposed panelists (-0.7% to 7.7% excess symptomatology and -0.3 to 5.8% lower PFT). Among patients a significant correlation between PFT and degree of occupational dust exposure was found. Significantly lower FEVl/FVC and excess in respiratory symptoms (with relative risks of 2.47–16.38) was present in healty smokers vs. non smokers as compared with COPD patients.Corresponding author.