Coldness and numbness of the lower limbs in patients with vibration syndrome were studied in correlation with the frequency of attacks of vibration-induced white finger (VWF), coldness and numbness of the upper limbs, and awakening at night due to numbness of the arm. Subjects were 229 patients aged 50-69 years without disease other than vibration syndrome who had mainly operated chain saws. The present study showed that patients with more frequent VWF attacks had a higher prevalence and frequency of coldness in the fingers, awakening at night due to numbness of the arm, and coldness and numbness in the legs. Particularly patients having almost daily attacks of VWF had a high prevalence of these symptoms. Positive correlation was observed in prevalence and frequency between coldness of the fingers and that of the legs, and between coldness and numbness in the legs. The prevalence of VWF, numbness and coldness of the fingers, and coldness of the legs was higher the longer the total chain saw operating period. The present findings suggest that patients with severe circulatory disturbances in the upper limbs have severe circulatoy disturbance in the lower limbs. Further studies on circulatory disturbances in the lower limbs are indicated, and their mechanism involved should be also pursued from the pathogenetic point of view.

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During the past decade, burnout syndrome has been widely discussed not only in the USA but also in Japan. To evaluate the state of “burnout, ” two major scales are available: the first is the Maslach Burnout Inventory (MBI) developed by C. Maslach and the other is the burnout scale by A. Pines.
MBI is suggested to be independent of and incompatible with Pines' burnout scale, but, Pines' burnout scale is predominantly used in Japan, while both are used in the USA.
Since hardly any studies of burnout using MBI have been made in Japan, we measured and analyzed MBI to evaluate the burnout state of doctors, nurses, caregivers, teachers and clerks who are engaged in “human services professions.”
The available data were subjected to factor analysis, reliability analysis and multiple regression analysis using Zung's Self-rating Depression Scale (SDS).
The following results were obtained.
1) The factor analysis showed that the factor loading pattern was similar to that of Maslach's, but two different factors were emerged in addition to the standard factors in the intensity subscale.
2) In the relationship with the state of depression, burnout is closely related to depression but simultaneously has its own factors. This suggests that burnout is not a subtype of the depressive state.

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A method based on interday fluctuation of contaminant concentrations for evaluating employee's exposure averages (8-h TWAs) was proposed in our previous report. The method was established on the assumption that daily exposure averages of the workers are lognormally distributed in actual workplaces.
The study was conducted to elucidate whether the distribution of daily exposure averages is statistically lognormal or not and to examine the relationship between sample geometric standard deviation (s_g) of worker's daily exposure averages and its estimate (s_g2) calculated by measurements for two consecutive days. These are critical for our proposed method. The data on daily exposure concentrations over five to six weeks were collected from workers exposed to cobalt, acetone, n-hexane, toluene, xylene, ethylbenzene and ethylacetate. The data on organic lead, inorganic lead and mercury exposures reported by Cope et al. and Lindstedt et al. were also used for the study.
The result can be summarized as follows:
1. Lognormal distribution of daily exposure averages was confirmed by plotting on normal probability paper and X²-test.
2. Median of s_g2 on daily exposure averages obtained from individual worker was smaller than s_g.
3. s_g calculated by a set of measurements for two consecutive days in every worker can be corrected by the equation: (s_g2) 1.48 in obtaining a better estimate of σ_g.
4. Statistical analysis on daily exposure averages of all workers showed that median of s_g2 was smaller than that of s_g, and 88% upper limit of s_g2 was equal to that of s_g.
5. Therefore, in evaluating TWA obtained by only single day's measurement using the proposed method, median of s_g representative of industrial hazardous substance exposure workplaces could be also corrected by the equation described above. However, correction of 90% upper limit of s_g2 is not necessary.

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Occupational exposures to potentially hazardous substances may vary considerably because of interday environmental behavioral fluctuations in the contaminant concentration. Such occupational exposures including those of non-monitored days can be theoretically evaluated by the following three ways: 1) assessment of geometric mean and geometric standard deviation, 2) assessment of arithmetic mean, and 3) assessment of upper limits of daily exposure distribution. In our previous report, an evaluation method on 95% upper limit or arithmetic mean of exposures was proposed. The method is useful, particularly, in case where only one or two days are being monitored, but may provide an approximate estimate because of statistical assumption. A sampling and decision scheme using one-sided tolerance limits (OTL) proposed by Tuggle (1982) can precisely evaluate the upper limits of exposures. However, many cases would be evaluated as “no decision, ” unless the sample size is extremely large in number.
We developed a revised method based on OTL for assessment of occupational exposures. The characteristic features of this method can be summarized as follows:
1. Upper limits of lognormally distributed 8-h exposure concentrations can be evaluated in comparison with an established standard.
2. A third OTL factor was introduced into Tuggle's scheme in which two OTL factors were used. A comparison between the upper limits of exposures and the standard can be made at 50% confidence level with the factor. The factor was calculated using non-central t-distribution.
3. The usefulness of the third OTL factor in the assessment of occupational exposures was confirmed by examining the performance characteristics of the method.
4. Finally, a classification scheme of the employee's exposure situation was presented on the basis of measurements for n days (n≥3).
The general application procedure of the method and an example of employee's exposure to n-hexane are also presented. In conclusion, the method can provide a precise estimate for exposure assessment and is very useful for practical purposes.

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毛髪と爪について,水銀の化学形による分別定量を行なった. 23歳から56歳までの男女それぞれ18人, 5人について,手の爪は3回,頭髪および足の爪はそれぞれ1回採取し,マゴス法の変法を用いて総水銀と無機水銀を測定した.
毛髪と爪の総水銀・無機水銀とも性差は見られなかった. 3つの形成時期の異なる手の爪の総水銀と無機水銀の値はいずれも同じ水準にあった.最も総水銀濃度の高かったのは頭髪で,次いで手の爪・足の爪の順であったが,無機水銀の場合には,頭髪と手の爪の水準がほぼ同じで,足の爪はそれより低い値を示した.また,総水銀に対する無機水銀の割合については手の爪が最も高い値を示し,これは手の爪が形成後の外部からの汚染が多いことを反映している可能性が考えられる.毛髪は爪よりも高い総水銀濃度であったが,これは毛髪と爪との間でその構成成分が異なることや,形成時の血液の供給の程度の差などが寄与していると考えられる.

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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.

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