Yutaka Ohsaki

Chromate lung cancer with special reference to its cell type and relation to the manufacturing process

The manufacturing process of the chromate industry can be classified into five steps. The main hazardous pollutants of the first step are trivalent chromate compounds, and those of the second and third steps are hexavalent chromate compounds. Analysis of the detailed working history of chromate workers with bronchogenic carcinoma, yielded the following results: the work history of chromate lung cancer patients in the first step, which produced mainly trivalent chromate dust, was rather short. Patients with small cell carcinoma were engaged mainly in the second step (98.1% of the total working months), where they were heavily exposed to hexavalent chromate dusts. Patients with squamous cell carcinoma were engaged rather evenly in the second and fourth steps, and somewhat longer in the third step. Comparisons of the exposure periods revealed that the working history of small cell carcinoma patients was significantly shorter than that of squamous cell carcinoma patients. There were many more heavy smokers among the squamous cell carcinoma group as compared to the small cell carcinoma patients. Based on these results, it is concluded that the cell type of occupational lung cancer was mainly small cell carcinoma when the exposure to carcinogenic agents was heavy, and that the carcinogenicity of chromate was derived mainly from hexavalent chromate rather than trivalent compounds.

p53 and Bcl-2 expression in pneumoconiosis-related pre-cancerous lesions and lung cancers : Frequent and preferential p53 expression in pneumoconiotic bronchiolar dysplasias

To explore the mechanism by which lung cancers excessively arise from pneumoconiosis, we determined the altered expression of p53 and Bcl‐2 by immunohistochemistry (IHC) in lung cancers, dysplasias and non‐cancerous pulmonary epithelia in pneumoconiotics in comparison with those from non‐pneumoconiotic patients. We examined p53 expression in squamous cell carcinomas (SCCs) and dysplasias separately in the central and peripheral zones of bronchial trees, based on observations that SCCs from pneumoconiotic patients occurr more frequently in peripheral epithelia than those from non‐pneumoconiotic patients (55 of 72 SCCs with pneumoconiosis vs. 33 of 72 SCCs without pneumoconiosis). Forty‐one of 72 patients with pneumoconiosis‐related lung cancers had altered p53 expression, which was comparable to the positivity of p53 expression in lung cancers without pneumoconiosis. p53 expression was observed significantly more frequently in bronchiolar dysplasias with pneumoconiosis than in those from non‐pneumoconiotic patients (13 of 23 vs. 4 of 22), while p53 expression was found in bronchial dysplasias with pneumoconiosis as frequently as those without pneumoconiosis. Moreover, in patients with pneumoconiosis, bronchiolar dysplasias exhibited p53 expression more frequently than bronchial dysplasias (13 of 23 vs. 4 of 19). When comparison was restricted to bronchiolar dysplasias from patients without lung cancer, p53 expression had a strikingly higher frequency in the dysplasias with pneumoconiosis than in those from non‐pneumoconiotic patients (8 of 15 vs. 0 of 14). Bcl‐2 occasionally was expressed in squamous metaplasias and basal cell hyperplasias, in contrast to p53, for which immunostaining was negative in these lesions. Altogether, our results show that pre‐cancerous and/or cancerous targets in pneumoconiosis may be distributed over a more peripheral zone than those in patients without pneumoconiosis. Int. J. Cancer 75:504–511, 1998.© 1998 Wiley‐Liss, Inc.

Micro-Spectrophotometric Nuclear DNA Analysis of Aspirated Cells from Thyroid Tumor

甲状腺腫穿刺細胞診の診断率は他の臓器に比して必ずしも高率とは言い難く, 良性・悪性の鑑別の困難なことが多い. 悪性細胞の特性をより客観的な指標でとらえるために, 甲状腺腫穿刺吸引細胞の核内Feulgen DNA量を測定し, そのヒストグラムパターンより, 良性甲状腺腫と悪性甲状腺腫の差異について比較検討した. 良性甲状腺腫の穿刺吸収細胞の核内Feulgen DNA量のヒストグラムは2c域に主分布がみられるパターンで4c域を越える細胞の出現頻度は12%を示した良性濾胞腺腫の1例を除いて全例4%以下であった. 悪性甲状腺癌の穿刺吸引細胞の核内Feulgen DNA量のヒストグラムは3c域に主分布がみられ, 広範囲に分布するパターンを示した. 4c域を越える細胞の出現頻度も39～60%と多く, 良性疾患とはまったく異なるヒストグラムパターンを示した. 核内Feulgen DNA量の測定により, 細胞診で比較的判定困難な場合でも, ヒストグラムパターンを分析することにより良性・悪性の区別が可能であることが示された.

Multiple Bronchogenic Carcinoma in Chromate Workers

クロムエ場従業員よりの3例の多発性肺癌-両側性-を経験した.内, 2例は両肺に生じた扁平上皮癌例であり, 1例は左肺に小細胞癌, 右肺に扁平上皮癌の同時発生例であった.扁平上皮癌両側発生例の内1例は手術を行った.1例は生前に診断を得たが病期が進行していたため死亡し、最後の例と共に剖検により子細に検索し得た.昭和56年春までにクロム工場従事者303名中, 21例の肺癌を見出し, この内, 剖検, 手術の可能な例8例であった.肺癌発生率の高頻度, また症例のような多発性肺癌を生ずることよりクロム塩類の強力な発癌性が示唆された.

A study on lung cancer among chromate workers Relationship between cell type and chromium compounds

クロム肺癌に発癌の関与する物質を検討するため, クロム酸塩製造工程別の従事期間を肺癌例と非癌例で検討した.肺癌例は6価クロムを取り扱う従事者に多かった.特に, 小細胞癌例では全従事期間のほとんど全てを水溶性の6価クロムを取り扱う工程に従事していた.クロム肺癌の発癌物質として, 水溶性の6価クロムが関与している可能性が示された.

AN ADULT CASE OF THE PARALYTIC POLIOMYELITIS SYNDROME INDUCED BY COXSACKIE VIRUS TYPE A-2

麻痺性ポリオ症候群paralytic poliomyelitis syndromeは,その原因としてポリオウイルスが広く知られているが,他の腸管系ウイルスや,ムンプスウイルス,ヘルペスウイルスなどのウイルスによつても発症する.コクサッキーA群ウイルスによつて麻痺を呈する例は,比較的少なく,とくにA2型によると確定診断されたものは,本邦では報告がない.われわれは, 27才男性で,感冒様症状をもつて発症し,四肢の弛緩性麻痺および顔面神経,舌咽神経,迷走神経麻痺を呈し, 2カ月後には,ほぼ正常にまで回復した症例を経験した.原因にかんしては,血清学的にコクサッキーウイルスA2型に対する中和抗体価の有意の上昇を認め,さらに便,髄液中から同型ウイルスを同定し,コクサッキーウイルスA型によつて発症したものと診断した.