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year groups). In order to assess the geo- graphical variability in mortality from

this disease, mortality figures for car- cinoma of the trachea, bronchus, and lung were collected from the publications of Statistics Canada for the period 1976-1980 for each of the ten Canadian provinces. All rates were standardized to the 1971 Canadi- an population for age and sex using the di- rect method. Rates for males vary by a fac- tor of nearly two between various geogra- phical regions of the country. They are lowest in the Prairie provinces of Saskat- chewan and Alberta, traditionally farming and, recently, oil producing provinces, at 33-44 deaths per year per i00,000 popula- tion. Similar rates were observed for the two Atlantic provinces of Newfoundland and Prince Edward Island, where fishing in the primary industry and source of income, at 33-48 deaths per year per i00,000 population. Rates are highest for the central provinces of Canada, namely Quebec, Ontario and Manotoba, and the Pa- cific coast province or British Columbia, where rates range 50-65 deaths per year per i00,000 population. These areas re- present, for the most part, the industri- alized and urban portion of the country with a number of major industries and where the bulk of the national GNP is pro- duced. Two notable exceptions are the two East coast provinces of Nova Scotia and New Brunswick which have rates between 46 and 60 deaths per year per i00,000 population. It appears that differences in urbanization and other economic factors may account for the higher mortality.

Co-Carcinogenic Action of Beta-Adrenergic Stimulator on 4-NQQ Pulmonary Carcinoge- nesis to Mice. Kimula, Y. Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki- 305, Japan.

The Clara cell of the terminal airway has been studied in many papers because of the following disputing target; i. the site of the syntesis of the pulmonary surfactant, 2. a role of metabolic acti- vation, and 3. the relation with pulmona- ry carcinogenesis. In this paper, the co- carcinogenic action of beta-stimulator on 4-NQQ (4-nitroquinoline-N-oxide) carci- nogenesis was examined and the role of the Clara cell on the pulmonary carcinogene- sis was discussed.

4-week old ddy male mice were divided into following 6 groups; A: peroral admi- nistration of beta-adrenergic stimulator (0.5% water solution of metaproterenol) from 4th to 31st week and a pericutanous injection of 4-nitrosoquinoline-N-oxide in oil at llth week. B: beta-stimulator;

from 4th to 7th week and 4-NQQ at llth C: beta-stimulator; 21st to 31st week and

4-~IQQ at llth week. D: no beta-stimulator; 4-NQQ at llth week. E: oil solvent only at llth week. F: beta-stimulator only; from 4th to 31st week.

At 31st week, the incidence of pulmonary tumor of each group was A: 74. B: 60. C: 53. D: 15. F: 16% and number of the tumor per a mouse was 2.7, i.i, 1.6, i.i, 0.2, 0.2 respectively.

This result suggests that beta-stimulator enhan- ces the 4-NQQ tumorigenesis, since the beta-sti- mulator increases smooth-surfaced endoplasmic re- ticuli of the Clara cells, it is suggested that the beta-stimulator enhances the metabolic acti- vation in the Clara cell and alters 4-NQQ to 4HAQO which has stronger mutagenetic activity than 4- NQO. Furthermore, histological appearances of the tumor cell are similar to the Clara cell. To cla- rify the pulmonary carcinogenesis, it is important to consider the stimuli brought via blood stream.

Clara Cell Adenomatous Proliferation in Dogs Ad- ministrated by Monocrotaline Pyrrole. ogata, T., Kimula, Y., Doi, M., Takizawa, H., Kuriyama, T., Watanabe, S. Department of Pathology, Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki 305, and Institute of Pulmo- nary Cancer Research, Chiba University, Chiba 208, Japan.

Toxic pyrrolizidine alkaloid monocrotaline has been believed to be not only cytotoxic but also carcinogenic by alkylating property of its highly reactive pyrrolic metabolites. Chronic administra- tion of purrolizidine alkaloid produces regene- rating nodules and hepatic cell carcinoma in the liver. Although the lung is a targent organ for toxic damage of the alkaloid, there has been no report on the development of carcinoma in lung.

The present study was designed for direct mono- crotaline pyrrole effects to the lung. A single injection of monocrotaline pyrrole into the pul- monary circulation of dogs produced multiple adeno- matous lesions with alveolar damage in the lungs after 8 weeks. The lesions were composed of cuboi- dal cells which spread extensively from the respi- ratory bronchioles to the alveoli. The prolifera- ting cells showed atypical features, but basically resembled the Clara cells of the normal terminal bronchioles in their ultrastructural basis.

This experiment supplies one evidence of Boyd's metabolic activation theory on the mechanism of carcinogenesis in the lung. The results reported here also suggested that the Clara cells as pro- genitor cells play an important role in the de- velopment of carcinoma by internal exposure of the lung to activated carcinogen.

Characteristics of Chromate Lung Cancer. Tsuchiya, E., Nakagawa, K., Kinoshita, I., Kita- gawa, T., Sugano, H. Cancer Institute, Tokyo, Japan.

We have been following 86 exchromate workers from a single factory for 8 years and so far found 8 lung cancer patients, 5 having double lesions. Five patients underwent surgery and/or autopsy and 3 biopsies. In addition, 2 patients without lung cancer were autopsied.

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The observed incidence of lung cancer in the chromate workers was 16 times hi-

gher than expected. The average duration

of exposure was 22 years in the lung can- cer cases and 14 years in all chromate workers. The latent period averaged 37 years and that was shorter the higher the chromium content in the lung, which was 60-468 ug/g in 5 lung cancer cases, 15- 16 ug/g in two non lung cancer cases and 4-10 ug/g in 3 non chromate control cases. The average number and duration of smoking of the 8 cancer patients were 18 cigs/day and 39 years, respectively. Histologically, 9 lesions from 6 patients were squamous cell carcinomas and 4 from 3 patients small cell carcinomas. No adenocarcinoma was found. Six lesions of atypical squamous

metaplasia were found in 3 cases with squamous cell carcinoma, whereas 4 lesions of atypical basal cell proliferation were detected in one small cell carcinoma case.

These data clearly indicate that chro- mate acts as a carcinogen and induces squamous and small cell carcinoma of the lung and that the epithelial atypia - cancer sequence is a main carcinogenic process.

Lung Cancer in the People's Republic of China. Tao-Ping, L. Guangzhou Medical College, Guangzhou, P.R.C.

The incidence of lung cancer markedly rose in recent 15 years, as the first to third cancer deaths in the four big cities on the Eastern coast. They are Shenyang, Beijing, Shanghai and Guangzhou. In common, they are industrial cities and on the del-

ta of big rivers. The incidence of these cities is around 20-30 per 100,000 popu- lation. Air and water pollution may be the primary cause. In certain mines, for example in Kuochew tin mine, the inciden- ce reached to 447 per i00,000 population. There is increasing tendency of adenocar- cinoma in males.

The treatment was chiefly surgical. Lobectomy was done in about 90% of cases. Sleeve lobectomy was first reported 5 years ago with good results. Preoperative radi- ation was used in certain hospitals to raise the rate of resection. Most authors in China prefered chemotherapy routinely after operation.

Chinese traditional medicine was very popularly used as a supportive measure. It worked well also to prevent leukopenia while chemotherapy.

The chest surgeons in many tumor centers have started to operate on patients above 70, or with respiratory cripple, or in the

third stage. Cases with chest wall extension or pleural metastasis have been also opera-

ted. The impression is: to operate is better than to abandon the patients.

In China, 5 years survival rate after opera- tion was about 25% to 55%; for small cells about 5% to 7%. 10-years survival was about 10%.

The Etiology and Epidemiology of Farmer's Lung Cancer in Xianwei County. Zhao, H.W., Shen, H.J. First Provincial People's Hospital of Yunnan. Kunming, People's Republic of China.

Among total population of 91,187, 39108 above 30 yrs. old, we examined 35,456 (90.66%) with clinical, x-ray, sputum cytological, somebody with fibrobronchoscopic examinations, diagnosed 262 lung cancer patients. 113 male and 149 fema- le. The peak age group is 50-59 yrs. in male, 40-49 in female. The incidence rate of farmer is 339.07/100,000, the office worker 118.11/ i00,000 and the coalmine & factory worker 15.41/ I00,000.

115 cases sputum positive, with 62.2% squa- mous cell, 24.53% adeno cell, 1.89% undifferen- tial cell 11.38% various cell carcinomas.

In Xianwei County the climate is cold, rich in coalmine resources. The people burns the coal with ground stove which has not chimney to warm themselves. The coal fume filled the room day and night ~ith a BaP concentration average 81.21 ug/100 m , highest reaches 559.24 ug/100 m 3.

The first cause of death in Xianwei County is the respiratory diseases, which reaches the rate of 205.26/100,000 per year.

There is no evident relation between tobacco smoke and lung cancer, because the women of Xianwei County never smoke. The incidence rate of female is higher than male.

In conclusion, we suggest that the ground stove with coal fume, environmental smut and respiratory diseases are the major causes of lung cancer in Xianwei County.

Epidemiology of Lung Cancer in Guangzhou, China. Yingxiu, D., Xiaowei, C., Zhuoqing, L., Jianwei, F. Department of Hygiene, Guangzhou Medical College.

Since 1971 the lung cancer death rate has in- creased rapidly in Guangzhou. A variety of data related to lung cancer has been collected for analysis such as population density, cigarette sales, coal consumption in households and in industries, petrol sales and concentration of air pollutants. These collected data have been analyzed for correlation or introduced into e-

quations of linear, multiple and step regression. A preliminary analysis suggests that coal con- sumption in households is the main factor.

To further identify the lung cancer inducing factor the indoors air quality, case-control study and analysis of lung cancer cell type have been investigated. The results showed that in- doors air pollution was at a higher level, the relative risk (RR) of exposure to coal fumes was higher than smoking in females, and a higher

percentage of epidermoidcardncmas incidence