1. Takahashi, S., Ogawa, K., Ohshima, H., Esumi, H., Ito, N., Sugimura, T.: Induction of aberrant crypt foci in the large intestine of F344 rats by oral administration of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine. Jpn J Cancer Res, 82: 135-137, 1991.

2. Tatematsu, M., Ogawa, K., Mutai, M., Aoki, T., Hoshiya, T., Ito, N.: Rapid regression of squamous cell hyperplasia and slow regression of basal cell hyperplasia in the forestomach of F344 rats treated with N-methyl-N’-nitro-N-nitrosoguanidine and/or butylated
hydroxyanisole. Cancer Res, 51: 318-323, 1991.

3. Okumura, M., Shirai, T., Tamano, S., Ito, M., Yamada, S., Fukushima, S.: Uracil-induced calculi and carcinogenesis in the urinary bladder of rats treated simultaneously with N-butyl-N-(4-hydroxybutyl)nitrosamine. Carcinogenesis, 12: 35-41, 1991.

4. Shibata, MA., Asakawa, E., Hagiwara, A., Kurata, Y., Fukushima, S.: DNA synthesis and scanning electron microscopic lesions in renal pelvic epithelium of rats treated with bladder cancer promoters. Toxicol Lett, 55: 263-272, 1991.

5. Hasegawa, R., Takahashi, S., Imaida, K., Yamaguchi, S., Shirai, T., Ito, N.: Age-dependent induction of preneoplastic liver cell foci by 2-acetylaminofluorene, phenobarbital and acetaminophen in F344 rats initially treated with diethylnitrosamine. Jpn J Cancer Res, 82: 293-297, 1991.

6. Hirose, M., Mutai, M., Takahashi, S., Yamada, M., Fukushima, S., Ito, N.: Effects of phenolic antioxidants in low dose combination on forestomach carcinogenesis in rats pretreated with N-methyl-N’-nitro-N-nitrosoguanidine. Cancer Res, 51: 824-827,1991.

7. Shirai, T., Tamano, S., Kato, T., Iwasaki, S., Takahashi, S., Ito, N.: Induction of invasive carcinomas in the accessory sex organs other than the ventral prostate of rats given 3,2-dimethyl-4-aminobiphenyl and testosterone propionate. Cancer Res, 51:1264-1269, 1991.

8. Ochiai, M., Ogawa, K., Wakabayashi, K., Sugimura, T., Nagase, S., Esumi, H., Nagao, M.: Induction of intestinal adenocarcinomas by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine in Nagase analbuminemic rats. Jpn J Cancer Res, 82:363-366, 1991.

9. Ito, N., Hasegawa, R., Shirai, T., Fukushima, S., Hakoi, K., Takaba, K., Iwasaki, S., Wakabayashi, K., Nagao, M., Sugimura, T.: Enhancement of GST-P positive liver cell foci development by combined treatment of rats with five heterocyclic amines at low doses. Carcinogenesis, 12: 767-772, 1991.

10. Tiwawech, D., Hasegawa, R., Kurata, Y., Tatematsu, M., Shibata, MA., Thamavit, W., Ito, N.: Does-dependent effects of 2-acetylaminofluorene on hepatic foci development and cell proliferation in rats. Carcinogenesis, 12: 985-990, 1991.

11. Fukushima, S., Hagiwara, A., Hirose, M., Yamaguchi, S., Tiwawech, D., Ito, N.: Modifying effects of various chemicals on preneoplastic and neoplastic lesion development in a wide-spectrum organ carcinogenesis model using F344 rats. Jpn J Cancer Res, 82: 642-649, 1991.

12. Tamano, S., Hagiwara, A., Suzuki, E., Okada, M., Shirai, T., Fukushima, S.: Time- and dose-dependent induction of invasive urinary bladder cancers by N-ethyl-N-(4-hydroxybutyl)nitrosamine in B6C3F1 mice. Jpn J Cancer Res, 82: 650-656, 1991.

13. Hasegawa, R., Fukuoka, M., Takahashi, T., Yamamoto, A., Yamaguchi, S., Shibata, MA., Tanaka, A., Fukushima, S.: Sex differences in o-phenylphenol and sodium o-phenylphenate rat urinary bladder carcinogenesis: Urinary metabolites and electrolytes under conditions of aciduria and alkalinuria. Jpn J Cancer Res, 82: 657-664, 1991.

14. Okumura, M., Shirai, T., Asamoto, M., Ogiso, T., Fukushima, S.: Lack of synergism in rat urinary tract carcinogenesis between prior uracil treatment and N-butyl-N-(4-hydroxybutyl)nitrosamine administration. Cancer Lett, 58: 81-85, 1991.

15. Fukushima, S., Kurata, Y., Hasegawa, R., Asamoto, M., Shibata, MA., Tamano, S.: L-Ascorbic acid amplification of bladder carcinogenesis promotion by K2CO3. Cancer Res, 51: 2548-2551, 1991.

16. Fukushima, S., Shibata, MA., Hirose, M., Kato, T., Tatematsu, M., Ito, N.: Organ-specific modification of tumor development by low-dose combinations of agents in a rat wide-spectrum carcinogenesis model. Jpn J Cancer Res, 82: 784-792, 1991.

17. Shirai, T., Fukushima, S., Kawabe, M., Shibata, MA., Iwasaki, S., Tada, M., Ito, N.: Selective induction of rat urinary bladder tumors by simultaneous administration of 3,2′-dimethyl-4-aminobiphenyl (DMAB) and butylated hydroxyanisole or butylated hydroxytoluene is associated with increased DMAB-DNA adduct formation. Carcinogenesis, 12: 1335-1339, 1991.

18. Nakamura, A., Shirai, T., Takahashi, S., Ogawa, K., Hirose, M., Ito, N.: Lack of modification by naturally occurring antioxidants of 3,2′-dimethyl-4-aminobiphenyl-initiated rat prostate carcinogenesis. Cancer Lett, 58: 241-246, 1991.

19. Tamano, S., Kurata, Y., Shibata, MA., Tanaka, H., Ogiso, T., Ito, N.: 13-week oral toxicity study of captafol in F344/DuCrj rats. Fundam Appl Toxicol, 17: 390-398, 1991.

20. Ito, N., Hasegawa, R., Sano, M., Tamano, S., Esumi, H., Takayama, S., Sugimura, T.: A new colon and mammary carcinogen in cooked food, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Carcinogenesis, 12: 1503-1506, 1991.

21. Hasegawa, R., Shirai, T., Hakoi, K., Wada, S., Yamaguchi, K., Takayama, S.: Synergistic enhancement of thyroid tumor induction by 2,4-diaminoanisole sulfate, N,N’-diethylthiourea and 4,4′-thiodianiline in male F344 rats. Carcinogenesis, 12:1515-1518, 1991.

22. Shibata, MA., Hasegawa, R., Sano, M., Shirai, T., Fukushima, S.: Timing effects of uracil-induced urolithiasis on amplification of second-stage promotion in rat bladder carcinogenesis. Jpn J Cancer Res, 82: 1077-1084, 1991.

23. Shirai, T., Joong, KD., Hakoi, K., Thamavit, W., Pairojkul, C., Hoshiya, T., Hasegawa, R., Ito, N.: Promotion of rat hepatocarcinogenesis by praziquantel. Jpn J Cancer Res, 82: 1085-1088, 1991.

24. Hirose, M., Uwagawa, S., Ozaki, K., Takaba, K., Ito, N.: Effects of butylated hydroxyanisole pretreatment on low dose N-methyl-N’-nitro-N-nitrosoguanidine- or N,N-dibutylnitrosamine-induced rat forestomach or esophageal carcinogenesis. Carcinogenesis, 12: 1773-1776, 1991.

25. Hirose, M., Ozaki, K., Takaba, K., Fukushima, S., Shirai, T., Ito, N.: Modifying effects of the naturally occurring antioxidants γ-oryzanol, phytic acid, tannic acid and n-tritriacontane-16,18-dione in a rat wide-spectrum organ carcinogenesis model. Carcinogenesis, 12: 1917-1921, 1991.

26. Mori, S., Murai, T., Takeuchi, Y., Hosono, M., Ohhara, T., Makino, S., Hayashi, Y., Shibata, MA., Kurata, Y., Hagiwara, A., Fukushima, S.: No promotion of urinary bladder carcinogenesis by sodium L-ascorbate in male ODS/Shi-od/od rats lacking L-ascorbic acid-synthesizing ability. Carcinogenesis, 12: 1869-1873, 1991.

27. Shibata, MA., Hirose, M., Tanaka, H., Asakawa, E., Shirai, T., Ito, N.: Induction of renal cell tumors in rats and mice, and enhancement of hepatocellular tumor development in mice after long-term hydroquinone treatment. Jpn J Cancer Res, 82:1211-1219, 1991.

28. Shirai, T., Yamamoto, A., Iwasaki, S., Tamano, S., Masui, T.: Induction of invasive carcinomas of the seminal vesicles and coagulating glands of F344 rats by administration of N-methyl-nitrosourea or N-nitrosobis(2-oxopropyl)amine and followed by testosterone propionate with or without high-fat diet. Carcinogenesis, 12:2169-2173, 1991.

29. Hagiwara, A., Tanaka, H., Tiwawech, D., Shirai, T., Ito, N.: Oral toxicity study of tragacanth gum in B6C3F1 mice: Development of squamous-cell hyperplasia in the forestomach and its reversibility. J Toxicol Environ Health, 34: 207-218, 1991.

30. de Camargo, JLV., Shirai, T., Kato, T., Asamoto, M., Fukushima, S.: Summation effects of uracil and other promoters on epithelial lesion development in the F344 rat urinary bladder initiated by N-butyl-N-(4-hydroxybutyl)nitrosamine. Jpn J Cancer Res, 82: 1220-1225, 1991.

31. Fukushima, S., Mutai, M., Hasegawa, R., Takahashi, S., de Camargo, JLV., Shirai, T.: Enhancing effects of carcinogens or promoters on bladder carcinogenesis in rats. J Toxicol Pathol, 4: 159-164, 1991.

32. Hagiwara, A., Hirose, M., Takahashi, S., Ogawa, K., Shirai, T., Ito, N.: Forestomach and kidney carcinogenicity of caffeic acid in F344 rats and C57BL/6NxC3H/HeN F1 mice. Cancer Res, 51: 5655-5660, 1991.

33. Murai, T., Mori, S., Hosono, M., Takeuchi, Y., Ohara, T., Makino, S., Takeda, R., Hayashi, Y., Fukushima, S.: Renal pelvic carcinoma which shows metastatic potential to distant organs, induced by N-butyl-N-(4-hydroxybutyl)nitrosamine in NON/Shi mice. Jpn J Cancer Res, 82: 1371-1377, 1991.

34. Imaida, K., Furihata, C., Tatematsu, M., Yoon, CH., Furukawa, F., Uneyama, C., Takahashi, M., Ito, N., Hayashi, Y.: Immunohistochemical and biochemical identification of pepsinogen isozymes in the hamster lungs: Induction by polychlorinated biphenyls. Toxicol Pathol, 19: 230-236, 1991.

35. Hasegawa, R., Shirai, T., Hakoi, K., Takaba, K., Iwasaki, S., Hoshiya, T., Ito, N., Nagao, M., Sugimara, T.: Synergistic enhancement of glutathione S-transferase placental form-positive hepatic foci development in diethylnitrosamine-treated rats by combined administration of five heterocyclic amines at low doses. Jpn J Cancer Res, 82: 1378-1384, 1991.

36. Uwagawa, S., Tsuda, H., Inoue, T., Tagawa, Y., Aoki, T., Kagawa, M., Ogiso, T., Ito, N.: Enhancing potential of 6 different carcinogens on multi-organ tumorigenesis after initial treatment with N-methyl-N-nitrosourea in rats. Jpn J Cancer Res, 82:1397-1405, 1991.

37. Thamavit, W., Moore, MA., Ruchirawat, S., Ito, N.: Lack of modulation effects of praziquantel on DMN-induced lesion development in the Syrian hamster liver. Cancer Lett, 61:229-232, 1991.

38. Cabral, R., Hoshiya, T., Hakoi, K., Hasegawa, R., Fukushima, S., Ito, N.: A rapid in vivo bioassay for the carcinogenicity of pesticides. Tumori, 77: 185-188, 1991.

39. Shibata, MA., Kagawa, M., Kawabe, M., Hagiwara, A., Fukushima, S.: Comparative promoting activities of phosphate salts on rat two-stage bladder carcinogenesis under conditions of equivalent urinary Na+ or K+ levels. Teratog Carcinog Mutagen, 11: 305-316, 1991.

40. Ito, N., Shirai, T., Fukushima, S.: Medium-term bioassay for carcinogens using multiorgan models. In: Ito, N. & Sugano, H. (eds.) Modification of Tumor Development in Rodents, Vol. 33, pp.41-57. S. Karger, Basel, 1991.

41. Fukushima, S. Modification of tumors development in the urinary bladder. In: Ito, N. & Sugano, H. (eds.) Modification of Tumor Development in Rodents, Vol. 33, pp.154-174. S. Karger, Basel, 1991.

42. Ito, N., Shirai, T.: Tumors of the accessory male sex organs. In: Turusov, V. & Mohr, U. (eds.) Pathology of Tumours in Laboratory Animals, Vol.1, pp421-443. International Agency for Research on Cancer, Lyon, 1991.

43. Tsuda, H., Ozaki, K., Uwagawa, S., Takahashi, S., Hakoi, K., Kato, T., Fukushima, S., Sato, K., Ito, N.: Analysis of the effects of modifying agents on proliferation and enzyme phenotype in focal preneoplastic and neoplastic liver lesions in rats. In: Columbano, A. et al. (eds.) Chemical Carcinogenesis 2, pp219-229. Plenum Press, New York, 1991.

44. Moore, MA., Thamavit, W., Tiwawech, D., Ito, N.: Cell death and proliferation in Opisthorchis viverrini-DHPN induced carcinogenesis in the Syrian hamster hepato-pancreatic axis. In: Columbano, A. et al. (eds.) Chemical Carcinogenesis 2, pp502-510. Plenum Press, New York, 1991.

45. Fukushima, S., de Camargo, JLV, Asamoto, M., Hasegawa, R., Tsuda, H.: Amplifying effects of uracil on multi-stage bladder carcinogenesis in rats. In: Columbano, A. et al. (eds.) Chemical Carcinogenesis 2, pp611-618. Plenum Press, New York, 1991.

46. Ito, N., Hirose, M., Takahashi, S.: Cellular proliferation and stomach carcinogenesis induced by antioxidants. In: Butterworth, BE. et al. (eds.) Chemically Induced Cell Proliferation: Implications for Risk Assessment, pp43-52. Wiley-Liss, Inc., New York, 1991.

47. Fukushima, S., Shibata, MA., Kurata, Y., Hasegawa, R.: The roles of L-ascorbic acid, urinary pH, and Na or K ion concentration in rat bladder epithelial cell proliferation with special reference to tumor promotion. In: Butterworth, BE. et al. (eds.) Chemically Induced Cell Proliferation: Implications for Risk Assessment, pp195-208. Wiley-Liss, Inc., New York, 1991.

48. Tatematsu, M., Shirai, T., Ogawa, K., Asamoto, M., Ito, N.: Proliferation kinetics and development of pepsinogen-altered pyloric gland cells in the glandular stomach of rats treated with chemicals. In: Butterworth, BE. et al. (eds.) Chemically Induced Cell Proliferation: Implications for Risk Assessment, pp445-455. Wiley-Liss, Inc., New York, 1991.