高知県下の山林労働者など,振動病と診断された患者107名および対照群として,同地域の山林で働くが振動の影響をほとんど無視できると思われる26名について,レオエンツェファログラフィーにより脳循環の状態を調べた. 患者はガラニナの症度分類により4型に分け,また,年齢別にも区分し,それぞれの成績を対照群と比較した. 脳循環の測定部位は,前頭部,後頭部および脳底部である.測定は安静時およびニトログリセリン(NG)0.3mg経口投与後の2回行った. 結果は次のとおりである.まず,各指標の年齢との回帰をみると,UTとURに,幾つかの部位,とくに脳底部において正の回帰があった.しかし,NG投与後は回帰は消失した.各指標の平均値について患者群を対照群と比較すると,40歳台以上,とくに50歳台ではUTとURはより大きく,MVは小さかった.全年齢を通してみると,どの測定部位でもUTとURは大きかった.また,MVは前頭部と後頭部でより小さく,DIはより大きかった.著しい変化は後頭部における各指標にみられた.しかし,NG投与後,有意な変化は脳底部のMVにしばしば認められた. 各症度別に対照群と比較すると,どの部位においてもUTとURはより大きく,MVは小さく,DIは大きい場合があった.NG投与後,とくに症度IVのDI,UTおよびMVに有意な変化を認めた.また,症度回帰がみられたのはURのみであった. NG投与後のMVの増加率をみると,患者群でも対照群でも,どの年齢でみても,脳底部が前頭部より大きかった.脳底部のMV増加率の比較では,全年齢を通してみると,患者群は159.5%,対照群192.3%でその差は有意であった.MV増加率の症度別の比較では,どの測定部位でも,有意な変化はなかった.しかし,症度IIとIVでは対照群より小さかった. レオグラム波形の解析では,異常波と認められたのは,患者群の前頭部91.1%,後頭部84.4%,脳底部80.6%であった.また,対照群では,それぞれ73.3%,53.9%,53.9%で,有意差があった.異常波が最高頻度に認められたのは症度IVの後頭部であった.NG投与後,対照の脳底部では異常波はO%であったが,患者群では6.8%に残存した. 患者は頭部症状として,頭痛,頭重感,しびれ感,めまいおよび耳鳴などを訴えるが,頭痛,頭重,しびれ感などは,大半の者(50.5%)は後頭部にあった. 以上の結果より,次の結論が得られた.すなわち,振動病患者の脳血管は,機能的収縮状態にあり,このためNGには比較的良好に反応し,拡張波を示す.しかし,とくに脳底部においては,異常波のままで残る率も対照に比して高かった. 振動病が最も重い症度IVでは,脳底部血管の器質的変化が推察された.

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An energy dispersive X-ray fluorescence spectrometer (EDX) has been applied to determine multielements in the workplace air. The standards for X-ray fluorescence analysis were prepared by the chelate precipitation method on polyvinyl chloride (PVC) membrane filter. And, the specimens were prepared to deposite various metal compounds of different chemical forms by the suspension method on PVC membrane filter, and they were determined with EDX and atomic absorption spectrometer (AAS). The results obtained were as follows. 1) Though there is a difference by each element, an amount less than 3 μg/cm² per unit area makes it possible to undergo multielement analysis, that is, it has no influence on fine particle effect (particle size; under 5μm). Then, effects of the X-ray intensity by different chemical forms are negligible. 2) At the presence the neighboring element and other elements this technique showed greater precision by carrying out on corrective treatment, etc. 3) The coefficient of variation of this technique was in the range of 2.5-6.5% at DDTC-Cu of 0.5-5.0 μg/cm², with the limit of detection for As: 0.002 μg/cm², Zn: 0.003 μg/cm², Pb: 0.003 μg/cm², Cu: 0.004 μg/cm², Ni: 0.003 μg/cm², Fe: 0.005 μg/cm², Mn: 0.008 μg/cm², Cr: 0.013 μg/cm², respectively. 4) Aerosols collected at the workplace were analyzed with EDX and AAS, and the obtained results showed good agreement with such regression line as y=1.04_x+0.04, the coefficient of correlation being r=0.995. From these results, this technique was found to be a very excellent method for monitoring of multielements in the workplace air.

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Tunnel work, digging a tunnel at the face, is a highly specialized job today. Many tunnel workers migrate from one place to another away from home throughout the year. They are exposed to hazardous factors such as dust, vibration, noise and so on, working under the two 12-hour shift system. Recently it has been reported that many workers who had suffered from pneumoconiosis and/or vibration disease returned to their home areas. The southern part of Oita Prefecture is well known as being one of the areas which supply many tunnel workers. In order to study the long-term effects of tunnel work on the health of the tunnel workers, the authors compared the mortality rate in the district supplying many tunnel workers with that of the district supplying few workers. Nine causes of death were chosen among many as indices indicating the characteristics of the structure of mortality in the district supplying many tunnel workers. The authors estimated these causes of death in relation to sex and age, analyzing simple correlations between the 9 causes of death and 33 socioeconomic factors. A principal component analysis of these indices was also carried out. The results were as follows. 1) A close relationship was found between tunnel work and three causes of death such as silicotuberculosis (010), tuberculosis (010-019, A6), and infective and parasitic diseases (000-136). 2) The other 5 causes of death such as diseases of the digestive system (520-577), neoplasms (014-259), all causes (000-999), stomach cancer (151, A47) and pneumoconiosis (515) were related not only to tunnel work but also to other regional characteristics such as fishery workers rate. 3) No relationship was found between tunnel work and death by cerebrovascular disease (430-438, A85). These results show that the tunnel work has an influence on the structure of mortality in the area supplying these workers. Note: ICD numbers are presented in parentheses.

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Experiments were conducted with a view to studying how the factors on the side of the mouse would affect the toxicity of cadmium (Cd) in the acute exposure to it. The factors studied were strain, sex, age in days and the interaction among these. So far these factors have been studied independently. But it is suspected that they are affecting each other, so a simultaneous exploration was attempted in the present study as to the effects of these factors on the Cd accumulation in various organs. The results obtained were as follows: 1. LD_{50&g; in acute Cd poisoning tended to be higher in C57BL/6 than in CF#1. Between the sexes it was higher in males than in females. As for the age of the mouse, the LDlt;50} was higher in those aged 40 days and 80 days than in those 20-day- and 160-day-old. 2. Changes in the body weight in acute Cd poisoning were analyzed by obtaining the variance for each factor. As a result a significant difference in the body weight change was revealed between the sexes, strains and ages of the animals and it was indicated that these factors modified the body weight changes in Cd poisoning. 3. Cd concentration in the liver significantly differed among the strains and age groups. In the kidney the Cd concentration had a significant difference among the strains, sexes, ages in days, and interaction between the strain and age, suggesting that these factors might affect the Cd accumulation in the organs. 4. The rate of Cd accumulated against the amount administered (accumulation rate) was studied in each of the organs. In the liver the accumulation rate was significantly affected by the age in days, and the interactions between strain and sex, strain and age, and sex and age, indicating that the modification occurred chiefly through the interactions among the factors. In the kidney the difference in the accumulation rate was attributed to strain, sex, and age in days, indicating that these factors affected the accumulation independently. From these results it was suggested that such factors as strain, sex and age in days affected directly or indirectly the manifestation of toxicity and accumulation of cadmium in the various organs to different degrees.

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