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FILE NAME Talc TALC DATE 1971 Sept DOC TALC120 DOCUMENT DESCRIPTION Medical Journal Article - Treated Rice and Japanese Stomach Cancer tract appears to be a macromolecule with a mass of approximately 30,000 to 50,000 daltons it is thermolabile and destroyed by trypsin It is apparently not stable on term storage even in the cold JOHN C. HOUCK HILTJE IRAUSQUIN SANFORD LEIKIN Research Foundation of the Children's Hospital of the District of Columbia Washington D.C. 20009 and George Washington University School of Medicine Washington D.C. 20005 References and Notes 1. W. Bullough and E. Laurence Proc Roy Soc London Ser B 151 517 1960 Exp Cell Res 33 176 1964 Nature 220 134 1958 3.3. J. Eur J. Cancer 4 607 1968 " Rytomaa and K. Kiviniemi Cell Tissue Kinet 1 329 1968 4. 4. J. Simnett and D. Chopra Nature 222 1189 1969 5. M. Voaden Exp Eye Rse 7 326 1968 5.6. J. Moorhead E. Tchernozemska A. Pirrie S. Hayes Nature 224 1207 1959 7. 7. E. Zipilivan B. Hudson W. Blatt Anal Bio- chem 30 91 1969 8. Supported in part by Medicine and Dentistry a contract Division of from the the Office of Naval Research 24 May 1971 ti] no firm mercial mineral mineralogic definition of comtalc and in most areas the talc forms much less than half of commercial talc The composition of commercial talc varies with the de- posit Vermont mines produce a platy or granular type of mineral relatively free of asbestos minerals 6 New York and California talcs contain more fibrous silicates including anthophyllite and tremolite 2 5 Respired asbestos and talc dust cause similar disorders in workmen Older talc workers show more than four times the expected incidence of lung and pleural cancer 7 Talc or talcose Treated Rice and Japanese Stomach Cancer minerals including contaminating asbestos are apparently the responsible Abstract The Japanese prefer dusted rice in their diet The incidence of stomach cancer in Japan is unusually high Most talc has some asbestos contaminants Epidemiologic evidence is presented that the contaminated talc on rice in the diet is the carcinogen or cocarcinogen responsible for the high incidence of Japanese stomach cancer carcinogens since where confirmatory evidence could be obtained all those talc workers with pleural and lung cancer also had talc pneumoconiosis Autopsies on six talc workers with talc pneumoconiosis showed the presence The high incidence of stomach cancer in Japanese men represents a challenging problem in cancer epidemiol- ogy Study of adjusted rates of mortality from stomach cancer in 24 countries showed that from 1962 to 1963 Japanese men had the highest rate for all nations the rate 67.96 per 100,000 in the male population was seven times that for men in the United States 1 Since talc frequently con- tains asbestos 2 and since workmen exposed to asbestos show a marked increase in gastrointestinal cancer es- pecially stomach cancer 3 pothesis that the increased the hy- rate of cancer of the stomach in Japan is due to ingestion of rice contaminated with asbestos seems attractive and has been recently suggested in a brief note 4 This report presents evidence for this relationship at somewhat greater length Rice grown in California and meant for the American consumer is milled mechanically Rice is prepared differently for the Japanese consumer It is milled and treated with glucose and then talc is added The talc is held to the surface of the grain and is said to preserve its flavor better Japanese con- sider this rice more tasty both here and in Japan Two percent of all talc produced in California from 1959 to 1963 was used as a rice additive primarily for export to Japan 5 Rice containers in Los Angeles markets intended for the Japanese customer usually bear the legend Coated with glucose and talc Optical microscopy of the ash of such bought rice showed 3.7 ^ 10 asbestos fibers per gram Fig ) Talc the mineral is a hydrous sili- cate of magnesium So are some forms of asbestos The difference between these two minerals is not in their chem- ical compositions but rather in their structure asbestos being fibrous and mineral talc being flaky or granular However commercial talc is composed not only of the pure mineral talc but also of fibrous silicates which are in part classifiable as asbestos There is oe a Fig 1. Photomicrograph of the ash of a specimen of rice intended for Japanese consumption and purchased in a Los Angeles market Arrows indicate asbestosform fibers The specimen contained 3.7 ^ 10 such fibers per gram of the characteristic asbestos body in the lungs of every one 8 When talc is examined by phase contrast microscopy from 8 to 30 percent of the particles are fibrous _ silicates Identifiable tremolite anthophyllite and chrysotile are also seen 9 The large talc deposits of New York and California regularly contain the amphibole asbestos minerals tremolite and antho- phyllite These are normal ingredients of commercial talcs from these areas Chrysotile asbestos occurs in talcose mineral deposits and then mined with the talc and veins in may be create a contaminant 9 Asbestos is an established carcinogen Not only does it cause lung cancer but it is associated with a substantial in- crease of morbidity from stomach cancer 3 Although chrysotile is the most important commercial fiber of asbestos there is no reason to regard the amphi- bole asbestos minerals as safe To the contrary in one study an amphibole asbestos mineral predominated in as- bodies in the sputum of a group of men exposed to asbestos and having a high incidence of mesotheliomata 10 The fact that talc workers exposed to fibrous talc which contains amphi- bole asbestos develop more pulmonary injury than do workers exposed only to talcs relatively free of fibrous silicates or amphiboles 11 indicates the pathogenicity of amphibole asbestos The Japanese preference for talc- coated rice means that rice eaters of that nation are exposed to the hazard of ingestion of amphibole asbestos as 17 SEPTEMBER 1971 1141 well as the unpredictable ingestion of chrysotile in areas where talc contains these carcinogenic materials Examination of the known epidemiologic characteristics of stomach cancer in Japanese strongly suggests that the causative agent is an additive to rice Not only is the incidence of stomach cancer high in eating Japanese but inside Japan stomach cancer is most prevalent in those prefectures where rice is the main staple it is less so in prefectures where rice is supplemented with cereal 12 and where the population eats heavily of the soybean preparations shoyo and miso 13 The morbidity from stomach tumors is greater among Japanese who eat rice with every meal than it is among Japanese who eat it less often among Japanese men who like milk and vegetables there is a lesser morbidity from stomach neoplasms 14 Experimental consumption of polished rice will cause ulceropapillomata of the forestomach of rats 15 These observations suggest a relation- ship between rice consumption and stomach cancer However the agent is not the rice itself since in other oriental countries where coated rice is not popular the incidence of stomach cancer is not unduly high A final indication of the environ- mental causes of stomach cancer in Japanese is provided by statistics concerning its prevalence in Japanese immigrants to western countries The incidence in Japanese males in Japan in 1962 to 1964 was 77.9 per 100,000 16 Japanese men in Hawaii had an incidence of only 45 per 100,000 Even this lowered rate was high compared to that for Chinese and Caucasian men of Hawaii who had incidences of 9.2 and 8.3 respectively Nativeborn Japanese have a higher incidence of stomach cancer than Japanese born in Hawaii or continental North Amer- ica 17 Dietetic studies on immigrant Japanese show that from 50 to 70 percent of their diet is Japanesetype food 18 The longer the immi- grant has been in the West the more western his diet becomes this increase in western food in the diet coincides with a decrease in the incidence of stomach cancer The hypothesis that the carcinogenic agent causing the high incidence of Japanese stomach cancer is asbestos- containing talc on rice appears therefore to satisfy the characteristics of the known epidemiology of that form of cancer in Japan However standardized mortality rates are also high for Chile Finland and Iceland where rice is not a major dietary staple 12 19 In view of the evidence for the Japanese the presence of contaminated talc as an additive to some nationally popular food should be suspected in these countries Further studies of the total contamination of the common diet by talc and asbestos in these nations with high incidences of stomach cancer are needed R. R. MERLISS 8820 Wilshire Boulevard Beverly Hills California 90211 References and Notes 1. T. Hirohata and M. Kuratsume Br J. Cancer 23 465 1969 2. L. A. Wright Talc and Soapstone California Division of Mines Publications Bulletin 176 San Francisco 1957 3. I. Selikoff J. Churg E. Hammond J. Am Med Assoc 188 22 1964 4. R. Merliss ibid 216 2144 1971 5. J. R. Wells in Mineral Facts and Problems U.S. Bureau of Mines Washington D.C. 1965 6. B. Weiss and E. Bochner Health 14 304 1967 Arch Environ M. Kleinfeld J. Messite O. Kooyman M. Zaki ibid p 663 8. M. Kleinfeld C. Giel J. Majeranowski J. Messite ibid 7 101 1963 9. L. Cralley M. Key D. Groth W. Lainhart R. Ligo Am Ind Hyg Assoc J. 29 350 1968 10. J. Stumphuis and P. Meyer Ann Occup Hyg 11 283 1968 11. J. Messite G. Reddin M. Kleinfeld Am Med Assoc Arch Ind Health 20 408 1959 12. M. Segi and M. Kurihara Tohuku J. Exp 72 1960 Med 169 Fujisaku 13. M. Segi L. Fukushima S. Fujisaku M. Kurihara S. Saito K. Asano M. Kamoi Gann 48 Suppl 1063 1957 14. I. Hirayama in Proceedings of the Interna- tional Conference on Gastric Cancer Maru- zen Tokyo 1968 15. A. Braunschwig and R. A. Rasmussen Can- cer Res 1 371 1941 16. R. Doll P. Payne J. Waterhouse Cancer Incidence in Five Continents Springer lag New York 1966 17. W. B. Quisenberry Acta Unio Int Contra Cancrum 17 858 1961 18. W. MacDonald Canadian Cancer Confer- ence 6th 1966 pp 451-459 19. N. Dungal and J. Sigurjonsson Br J. Can- cer 21 270 1967 7 June 1971 s Cyclic Adenosine Monophosphate in Brain Areas Microwave Irradiation as a Means of Tissue Fixation Abstract Amounts of cyclic adenosine monophosphate in discrete regions of the brain were estimated after exposure of rats to microwave irradiation Amounts were highest in the cerebellum and brainstem intermediate in the hypothalamus and midbrain and lowest in the hippocampus and cortex Decapitation increased the concentration of cyclic adenosine monophosphate in all brain areas although the increase in the cerebellum was three to four times greater than that in other areas Microwave irradiation may provide a means of rapidly fixing brain tissue in situ while permitting easy dissection of the brain In this way artifacts produced by decapitation can be eliminated and concentrations of stable compounds in the brain can be estimated under conditions which more closely approximate those in vivo Rapid fixation of cerebral tissue in situ is required to obtain valid estimates of many brain components Decapitation and delayed fixation lead to significant changes in brain glycogen 1 and in glucose lactic acid 2 and other sub- strates and cofactors of the Embden- Meyerhof pathway 3 At present fix- ation of the brain in situ is carried out by freezing whole animals in liquid nitrogen or cooled isopentane Even under such conditions deep brain structures Table 1. Amounts of cyclic AMP in brain areas after microwave irradiation Values represent the mean and standard error of the mean from six separate determinations Area Cerebellum Brainstem Hypothalamus Midbrain Hippocampus Cortex Cyclic AMP nmole 1.86 -0.06 1.87 -0.06 1.60 -0.04 1.43 -0.11 0.84 -0.09 0.74 -0.06 can require up to 75 seconds to reach C 4 These freezing techniques also require restraint of the animal and pro- duce considerable stress before it dies Dissection of the frozen brain is almost impossible and therefore experiments must be done on whole brains These problems have prevented the measurement of cyclic adenosine monophosphate AMP in discrete brain regions induced changes in concentrations of cyclic AMP in specific brain areas might easily be masked by massive amounts of unresponding tissue when nucleotide concentrations are measured in the frozen whole brain Furthermore the concentration of cyclic AMP in the whole brain increases severalfold within seconds after decapitation thereby prohibiting rapid dissection after death 5 Stavinoha 6 reported that amounts of acetylcholine in the brains of rats that had been killed by being exposed to microwave irradiation were significantly higher than previously reported 1142 SCIENCE VOL 173 1971