1) 製薬工場従業員にみられた職業性薬剤アレルギーの追跡調査の結果から,抗原暴露レベルと発症率の間に量-反応関係が存在するか否かを検証し,あわせて素因のかかわりについても検討した.
2) 抗原は粉末状の消炎酵素剤(Bromelain, Trypsin)と抗生剤(Cephalexin, Ampicillin, Amoxycillin)であり,対象者41名のうち24名が消炎酵素剤を,全員が抗生剤の暴露を受けている.観察期間は消炎酵素剤では1970年から,抗生剤では1975年から1984年4月までとした.アレルギー発症は特殊健康診断と健康管理資料とから確認した.アレルギー素因の有無はアトピー性疾患の既往・家族歴(素因(I))と,判別分析で発症に寄与すると判別された既往・家族歴(素因(II))の二つの方法で推定した.発症率は人年法で求めた.暴露レベルは作業内容から推定した.量-反応関係は, (1)同種抗原に対する同程度の暴露濃度レべルの時の,暴露頻度レベルと発症率の関係, (2)同種抗原に対する同程度の暴露頻度レベルの時の,暴露濃度レベルと発症率の関係をみることで検討した.
3) その結果, (1)対象者全体では暴露頻度レベル,暴露濃度レベルの高い群が有意に高い発症率を示すこと, (2)この関係は素因(I)を有する集団の間で特に著明にみられること, (3)素因(II)を有する集団の間では暴露頻度レベルの多い群で有意に高い発症率を示すこと, (4)素因(I)または素因(II)を有しない集団の一部で暴露頻度レベルの高い群が有意に高い発症率を示すことなどが知られた.
これらの結果は抗原暴露レベルと発症率の間に量-反応関係が存在することを示唆するものと考えられた.

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A questionnaire survey was conducted on 271 workers of microelectronics company. The questionnaire included such items as age, years of service, working conditions and subjective symptoms related to visual, musculoskeletal and general status.
The following results were obtained:
a) Of these workers, approximately 80% operated visual display terminals (VDT). The years of service for most were less than 4 to 5 years with the average being about 2 years (Fig. 1). The working hours per day on the VDT for most of them was less than 90 min, although some workers operated VDT for 3 or more hours per day (Fig. 2).
b) A high incidence of complaints of visual function, i.e. eye strain and blurring of distant objects, was observed. Some also complained of musculoskeletal and general symptoms (Table 1).
c) The rates of these subjective symptoms increased with years of service (Figs. 4 and 5), while the complaint rates decreased with age (Fig. 3). Significant positive correlations were found between most of these complaint rates and length of service (Table 2), although correlations between the complaint rates and age were generally non-significant but negative.
d) The complaints tended to increase with working hours per day, although the operators who worked for longer period per day did not seem to complain as much as those who did not work so long (Fig. 6).
In conclusion, the results of this questionnaire suggest that the effects of visual display terminals (VDT) work accumulate gradually over months and years.

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Studies were made with male Wistar rats on the effects of 50% food restriction on the metabolism of eight organic solvents (chloroform, carbon tetrachloride, 1, 2-dichloroethane, 1, 1-dichloroethylene, trichloroethylene, benzene, toluene and styrene) and on the hepatotoxicity induced by carbon tetrachloride inhalation at 400 ppm for 4 h. The activities of liver drug-metabolizing enzymes for these solvents were enhanced almost equally without exception by one-day food restriction, although the restriction produced no significant increase in the microsomal protein and cytochrome P-450 contents. Carbon tetrachloride hepatotoxicity was enhanced by the food restriction, as evidenced by a marked increase of serum glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) activities in the food-restricted rats. Histological findings of the liver also supported this finding. Thus, food restriction enhances metabolism of organic solvents in the liver, and can modify toxicity of some chemicals such as carbon tetrachloride, which need metabolic activation to become cytotoxic.

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有機溶剤トルエンの中枢神経系への急性影響を「濃度・暴露時間積と生体のパフォマンス変化」の面から明らかにすることを目的として行動中毒学的手法を用いて検討した. Wistar系ラットを光警告つき条件回避反応で訓練し,一定の回避成績を示すようになった時点でトルエンに125～4,000 ppmの6段階の濃度におのおの4時間単回暴露し,暴露前後7時間のレバー押し数,回避数,有効回避率,光刺激に対する反応潜時を測定した.
得られた結果は以下のとおりである.
1) トルエン125, 250, 500 ppm暴露では,暴露開始後20分間は有効回避率の有意の減少が見られた. 125 ppm暴露では暴露240分目の有効回避率が対応コントロールに比べて低かった.
2) トルエン1,000 ppmと2,000 ppmでは濃度と暴露時間に比例してレバー押し反応数の顕著な増加と有効回避率の低下が認められた. 2,000 ppm 4時間目には反応数は暴露前の150%を越え,有効回避率は暴露前のパフォマンスの70%に低下していた. 1,000 ppmおよび2,000 ppmトルエン暴露時には,いずれも暴露後2時間目以降は光刺激に対する反応潜時の有意の短縮も認められた.
3) 4,000 ppm暴露の場合は,最初の40分間は反応数の著しい増加を示すが,その後次第に麻酔性の行動抑制を示し, 8匹中6匹のラットは痙攣および運動失調を呈した. 4,000 ppm暴露終了後は全ラットの反応数は増加し興奮状態を示した.有効回避率は暴露打ち切り2時間後も回復しなかった.
低濃度および高濃度トルエン暴露の行動影響について,考察を加えるとともに,方法についての検討を行って,有機溶剤の中枢神経系への影響を明らかにするうえでラットの弁別条件回避行動の有用性を示した.

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An improved method for the determination of urinary δ-aminolevulinic acid (ALA) as an indicator of lead absorption is described. It is a modification of the analytical procedure described by Tomokuni and Ogata in 1972.
In the present method, the spot urine from lead-exposed workers which was diluted 3-fold with distilled water beforehand was used as the sample to eliminate as much as possible the urinary matrix interference. In addition, methyl acetoacetate was used as the condensation reagent for ALA-pyrrole, because the color intensity of ALA-pyrrole was higher with the use of methyl acetoacetate than that with ethyl acetoacetate which was used in the original method.
The urinary ALA value determined by the present method was similar to that measured using an internal-standard addition method. This method is suitable as a rapid and inexpensive screening procedure for the routine quantitative analysis of urinary ALA.

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