The present study was conducted to clarify the direct effects of active listening (AL) training given to middle managers in a local government. Altogether, 345 middle managers participated in 13 AL training sessions over two years. We developed the Inventive Experiential Learning (IEL) method, and used it as the central training method in this study. To investigate how well the participants learned AL, we asked the middle managers to answer a shorter version of the Active Listening Attitude Scale (ALAS) consisting of two subscales-i.e. "Listening Attitude" and "Listening Skill"-before training, one month after and three months after training. Altogether, 284 middle managers answered the questionnaire three times. The scores of each subscale were analyzed by repeated measurement analysis of variance. The participants were divided into three groups using the percentile values of the original sample of ALAS, i.e. low-score group (-24%), medium-score group (25-75%) and high-score group (76%-), and the proportionate changes were examined. The results showed both the "Listening Attitude" and "Listening Skill" subscales increased significantly after training. Analysis of the percentiles showed that the proportion of the low-score group decreased and that of the high-score group increased in both subscales, from one to three months after training. These changes are considered to indicate that the participants have learned AL although they attended AL training for only one day.
ここに述べる,有害物質の許容濃度,および騒音,衝撃騒音,高温,全身振動などの各許容基準は,これらの環境要因による労働者の健康障害を予防するための手引きに用いられることを目的として,日本産業衛生学会が勧告するものである.
We investigated the background levels of total mercury in blood and urine samples from Japanese subjects without occupational exposure to mercury vapor. Blood and urine specimens were decomposed in sealed Teflon containers, and total mercury concentration was measured by reductive vaporization-gold amalgam capture-atomic absorption spectrophotometry. The mean total mercury concentration in the blood of 56 women aged 34-65 was 18.2 +/- 9.9 ng/ml (range 3.9-56.8 ng/ml). The mean total mercury concentration in the urine of 130 men aged 22-39 was 2.33 +/- 1.50 micrograms/l (range 0.27-10.26 micrograms/l). The mean total mercury concentration in urine adjusted by specific gravity was 2.19 +/- 1.15 micrograms/l (range 0.68-7.68 micrograms/l), and that adjusted by creatinine was 1.51 +/- 0.68 micrograms/g creatinine (range 0.39-4.21 micrograms/g creatinine). These concentrations did not differ greatly from those reported from Europe and Japan. In expressing the total mercury concentration in urine, the creatinine-adjusted range between the minimum and maximum values was smaller than the range adjusted by specific gravity.
Two male workers were acutely intoxicated with gas produced by heating tar epoxy resin paint, and developed peripheral neuropathy. To assess the work atmosphere, we analyzed the degradation products by GC-MS. The major toxic products emitted by heating tar epoxy resin were hydrogen cyanide, phenol, and benzene, as well as naphthalene. From 1 m2 of the surface of steel plates painted with tar epoxy resin, 2.4 g of hydrogen cyanide, 9.6 g of benzene, and 1.2 g of nephthalene were produced by heating at 1000 degrees C, At 700 degrees C, the amounts of phenol and p-isopropylphenol produced were 3.7 g and 0.57 g, respectively. Based on these results and the area of steel surface burned, the concentration of hydrogen cyanide, benzene, and phenol in the atmosphere of work environment was estimated to be 16, 64 and 24 mg/m3, respectively. Some of the symptoms of the workers including peripheral neuropathy might be related to the sole or cooperative action of the foregoing toxic chemicals mentioned above.
To survey methods for assessing stress and to examine the relationship of stress to health and the factors of lifestyle, we reviewed the literature on stressors and stress reactions. Firstly, we reviewed the representative methods for assessing stressors. Secondly, self-report questionnaires based on a theoretical model of occupational stressors were surveyed and factors in work stress were listed. Then, we reviewed stress reactions including physiological, psychological and behavioral reactions. Finally, we examined the relationship of perceived stress measured by a single question to mental health status determined by the General Health Questionnaire (GHQ-28), lifestyles and personality based on the Egogram in Transactional Analysis. It is suggested that we need to assess subjective aspects as well as using objective indices such as data from physical examinations, to evaluate the level of stress and to promote mental health.
Acute oral toxicity (LD50-value) of organic chemicals to rats was analyzed by using solubility parameter (delta c), a thermodynamic parameter, of the chemicals. Certain parabolic correlations were established between logarithm of LD50-value (mmol/kg body weight, rats) and delta c of all the collected chemicals (n = 144, R = 0.578), alcohols (n = 29, R = 0.587), ketones (n = 7, R = 0.962), aldehydes (n = 9, R = 0.621), ethers (n = 5, R = 0.890), acetates (n = 7, R = 0.670) and aromatics (n = 84, R = 0.736). Introducing molar volume (Vc) to the above equations could not improve the correlation. In the study, we assumed that as for acute toxicity, chemicals taken into the mammals through biological membrane first disturb the homeostasis, which causes certain biological reactions (i.e. death) and that amounts of the chemicals intaken are regulated by their solubility in the membrane. Based on the assumption, we drew a theoretical equation, which describes LD50 by a parabolic function of delta c. A regression analysis using the equation gave significant correlations as stated above, which incarnates the assumption. A solubility parameter of 2.30 x 10(4) (J/m3)1/2 was also determined for the biological membrane (absorption site) of rats. For comparison, log P was used to describe LD50 of all the chemicals, but no correlation was established (R = 0.164-0.443).
Acute dermal toxicity (LD50-value) of organic chemicals to rabbits was analyzed by using solubility parameter (delta c), a thermodynamic parameter, of the chemicals. As it was observed in the previous studies with rats and mice, parabolic correlations were also established between logarithm of LD50-value (mmol/kg body weight, rabbits) and delta c of all the collected chemicals (n = 56, R = 0.498), alcohols (n = 19, R = 0.857), ketones (n = 7, R = 0.711), aldehydes (n = 7, R = 0.633) and aromatics (n = 20, R = 0.613). Introduction of molar volume (Vc) to the above equations did not improve the correlations. In the study, we assumed that chemicals absorbed dermally by the mammals similarly disturb the homeostasis, as in acute oral toxicities of organic chemicals to rats and mice. We successfully confirmed the theoretical equation regardless of species and routes of administration by establishing statistically significant correlations with all the collected chemicals, alcohols and aromatics. By analysis, we could determine the solubility parameter of 2.24 x 10(4) (J/m3)1/2 for the biological membrane (absorption site) of rabbits. As the dermal delta c-values which dip the LD50-values for rabbits are approximately the same as in acute oral toxicities with rats and mice, common deleterious effects and mechanism may be working at the common target sites. The regression curves of LD50-values of rabbits, however, are slightly higher than those of rats and mice, which may reflect the difference in amounts of the chemicals absorbed by the body.(ABSTRACT TRUNCATED AT 250 WORDS)
An assessment of mental stress and fatigue was undertaken in 12 male students who did their best to perform a calculating task (addition and subtraction of 2-digit numbers) for 11 hours on a workday and rested without any task for 11 hours on a restday. During the work period, occipital midline beta-2 (Oz beta 2) amplitude, urinary adrenaline (A) and noradrenaline (NA) excretion, heart rate (HR), blood pressure (BP), subjective rating of tiredness (SRT), and subjective symptoms of fatigue (SSF) were higher than those during the rest period. Oz beta 2 amplitude, diastolic pressure (DP), critical flicker fusion value (CFF), and performance level (number answered, percent correct) remained unchanged over the rest/work period. Moreover, A and NA excretion, HR, and systolic pressure (SP) changed parallel with their resting level. With the lapse of working hours, SRT and SSF elevated. These results suggest that performance of calculating task causes mental stress which remains constant throughout the work period and that subjective fatigue increases with extension of working hours.
Acute oral toxicity (LD50-value) of organic chemicals to mice was analyzed by using solubility parameter (delta c), a thermodynamic parameter, of the chemicals. As it was observed in the previous study with rats, parabolic correlations were established between logarithm of LD50-value (mmol/kg body weight, mice) and delta c of all the collected chemicals (n = 85, R = 0.626), alcohols (n = 10, R = 0.683), ketones (n = 7, R = 0.631) and aromatics (n = 62, R = 0.645). Introducing molar volume (Vc) to the above equations did not improve the correlations. Although statistically significant correlations were not found in alcohols and ketones with mice, we successfully assured the theoretical equation regardless of species difference by establishing significant correlations with all the collected chemicals and aromatics. By analysis, we could determine the solubility parameter of 2.27 x 10(4) (J/m3)1/2 for the biological membrane (absorption site) of mice. As the delta c-values which dip the LD50-values are approximately the same for mice and rats, common deleterious effects and mechanism may be working at common target sites. In addition, no species difference in sensitivity (toxicity) was found for the aromatics. For comparison, log P was used to describe LD50 of all the collected chemicals, but no correlation was established (R = 0.004-0.418).
The effects of Breslow's seven health practices on health were examined. The Today Health Index (THI), a questionnaire for self-evaluation of physical and mental health, was applied to male workers of a private company as well as their wives. The subjects resided in the suburbs of Tokyo and the average ages of the males and females were 41.5 and 38.4 years, respectively. Statistical results were obtained using Mann-Whitney U-test, analysis of covariance, and Hayashi's quantification theory I. A statistically significant decrease in the THI scale scores among subjects observing six or more health practices when compared with those observing three or less was demonstrated in vague complaints and irritability in males, and in respiration in females. In males, the THI scale scores of vague complaints, respiration, and the mouth and anus significantly decreased by sleeping well. Those of irritability and irregularity of life decreased by not smoking and those of vague complaints and irritability decreased by not eating between meals. In females, the THI scale scores of vague complaints, eye and skin, and the mouth and anus significantly decreased by exercising regularly. Those of irregularity of life decreased by not smoking. Those of respiration decreased by good weight control. Those of respiration and the mouth and anus decreased by not eating between meals. Exercising regularly in females was a good predictor of vague complaints using multi-variate analysis adjusted for age. Subjective evaluation of health improved by Breslow's recommended health practices.
アセトンは産業現場で広く使用されている有機溶剤である.生体内に吸収されたアセトンの一部は,代謝を受けずにそのまま尿中に排泄されることが知られている.アセトンの生物学的暴露指標として,尿中アセトン濃度の測定が広く行われている.尿中アセトンの測定法はこれまで吸光光度分析法,ガスクロマトグラフ分析法,ヘッドスペースガスクロマトグラス分析法が報告されているが,これらの分析法には特異性に欠ける点,種々の技術的問題点や高価な機器を必要とするなど,必ずしもルーチン分析に適しているとは言い難い.そこで著者らは2,4-ジニトロフェニルヒドラジン(DNPH)を用いたアセトンの誇導体化,有機溶媒抽出,逆相高速液体クロマトグラフィー(HPLC)から成る尿中アセトンの分析法を検討した.標準液または尿0.5 mlを共栓試験管にとり, 0.25% DNPH溶液0.4 mlを加えて5秒間撹拌した. 5分経過後, n-ヘキサン3.0 mlを加えてアセトン-DNPH誇導体を抽出した. n-ヘキサン層2.0 mlをとり,濃縮乾固し,アセトニトリルに溶解しHPLCに注入した. HPLCの条件は次のとおりである.分析カラムにはTSK gel ODS80TM (4.6 mm i. d.×150 mm),移動相にはアセトニトリル-水(80:20, v/v)を用い,流速は1.0 ml/minとした. DNPH誘導体の検出には365 nmを用いた.本測定法は尿中に存在し, DNPHと反応するヒドロキシアセトンやアルデヒド及び他のケトン類(メチルエチルケトン,メチルイソブチルケトン)とも完全に分離できることが分かった.検量線は少なくとも2.70 mmol/lまでは直線性を示し,検出下限は1 μmol/lであった.アセトン-DNPH誘導体の安定性を検討した結果, 4℃保存では少なくとも2日間は誘導体の濃度に変化は認められなかった.また,回収率,再現性とも良好な結果が得られた.したがって,プレラベル法を用いた本HPLC法は簡易,迅速で多量の検体を処理するルーチン分析に有用であると思われる.
The number of chemicals used in industry is increasing, and as a consequence workers in chemical industries are thought to have many opportunities for being exposed to chemicals. For organic solvents, although a number of studies have shown the toxicity of individual chemicals, there are a relatively small number of studies that have described their toxicity in terms of a quantitative structure-activity relationship (QSAR). In the present article I first introduced an outline of the method of QSAR (Hansch's method), and then reviewed the literature on QSAR of industrial chemicals, principally organic solvents and related chemicals as follows:1) A review was made of the studies of general toxicity of chlorophenols, alcohols, amines, anilines, phenols, ethers, alkanes, ketones, acrylates, methacrylates and nitriles. In almost all cases, the general toxicity is related to log P, in which P is n-octanol/water partition coefficient, indicating the importance of the hydrophobicity of chemicals for their toxicities.2) The QSARs of anesthetic organic solvents were reviewed. The chemicals analysed were ethers, alkanes, ketones, miscellaneous chemicals and anesthetic gases. It is shown that the relative anesthetic potency of anesthetic gases depends not only on the hydrophobicity expressed by log P but on a polar factor, while the potency of other chemicals depends largely on log P.3) The relationship of the structure of organic solvents to skin penetration or absorption was reviewed. QSARs reveal that the potency of skin penetration or absorption of solvents is a function of water solubility, log P or hydrogen bond number, each relating to hydrophobicity.4) Some organic solvents have an effect on the upper respiratory tract. The established QSAR models considerably resemble corresponding equations for gas/liquid partition coefficients into organic bases such as tricresylphosphate.5) The ecotoxicity of chemicals including solvents was reviewed. Overall, the relative toxic potency of chemicals is related linearly to log P, indicating the importance of hydrophobicity in determining the toxicity of chemicals.6) Although no QSAR has modeled the mutagenic activity of organic solvents, a few studies show the relationship between the structure and mutagenicity of haloalkenes. Finally, if QSAR could model the toxicity of a series of chemicals, it would serve our purpose of understanding the mechanism of toxicity and of predicting the toxic potency of chemicals in the same series tested.
The medical examination of workers exposed to lead was conducted as part of the activity of the Occupational Safety and Health Center (OSHC) Project in the Philippines (JICA Project). The subjects of the medical examination were 21 male and 193 female workers of a semi-conductor plant (abbreviated A company), 59 male and 6 female workers of a refrigerator manufacture (B company); 199 male workers of a storage battery manufacturer (C company); and 107 male and 6 female workers of a lead smelter (D company). Among the examination items were questions regarding occupational history, subjective complaints and objective signs, determination of blood lead levels, urine delta aminolevulinic acid levels, and examination for anemia. The survey was conducted from June to September in 1990. The following results were obtained: 1) The mean age of the workers ranged from 21.8 to 33.8 years. Those of companies A and B were younger than those of companies C and D. The mean employment duration of males at C company was 10.7 yr, and the longest among the four companies. That in both sexes for A company was 1.8 yr and the shortest among the above mentioned companies. 2) The blood lead geometric mean levels of companies C and D showed the highest concentration. The level in males of C company was 64.5 micrograms/dl and that of D company was 80.8 micrograms/dl. The level in females of A company was 9.9 micrograms/dl and the lowest in concentration. The urine delta aminolevulinic acid geometric mean levels were less than 6.0 mg/l in the four companies. There was no company having hemoglobin mean values less than 14.0 g/dl in males or less than 12.0 g/dl in females. 3) The proportion of blood lead levels of 60 micrograms/dl or more was 67.3% in males of C company, and 89.7% in males and 16.7% in females of D company. The proportion of urine delta aminolevulinic acid levels of 6 mg/l or more was 1.0% in females of A company, 20.1% in males of C company, and 43.0% in males of D company. The proportion of hemoglobin values less than 14.0 g/dl in males or less than 12.0 g/dl in females was 4.7% in females of A company, 1.7% in males of B company, 3.5% in males of C company, and 12.1% in males of D company.(ABSTRACT TRUNCATED AT 400 WORDS)
Exercise stress test is useful for the early detection of coronary artery disease and is recommended as a medical clearance test before the initiation of exercise training. However, when applied to apparently healthy people, there are many false positive results. It is therefore necessary to determine indications for stress testing, but few data are available in Japan. In this study, we performed exercise stress test in apparently healthy men to investigate the incidence of exercise-induced ST segment changes and their relationship to coronary risk factors. The subjects were 2,187 men who underwent symptom-limited exercise stress test at a health-promotion center in Tokyo. Those with a history of cardiovascular disease were excluded. They underwent symptom-limited exercise stress test on a treadmill with a modified Bruce protocol or on a cycle ergometer with a ramp protocol (20 watts per minute). Twelve-lead electrocardiogram was recorded every 3 min. Cardiologists evaluated the exercise ECG responses, and advised those with abnormal ST segment changes (Group A) to undergo further examinations at a cardiovascular hospital. The results of further examination such as exercise scintigraphy and/or coronary angiography were obtained. Twice the number of subjects with normal exercise responses were selected as age-matched controls (Group N) to compare the coronary risk factors between the two groups. Twenty-nine subjects had abnormal ST segment changes (1.33% of the total subjects) (Group A). Their mean age was 57 years (38 to 76). Among these, 27 had ST segment depression and 2 had ST elevation.(ABSTRACT TRUNCATED AT 250 WORDS)
