A newly synthesized fluorescent TPA derivative, O-(N-dansylamino-3-tetradecanoyl)-12, O-acetyl-13-phorbol (Dansyl-TPA), inhibited metabolic cooperation of Chinese hamster V79 cells in culture and also the specific binding of [³H] phorbol dibutyrate to V79 cells. Dansyl-TPA should be a valuable tool for studying the cellular targets of TPA.

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Plasmids containing v-ras^H and Ecogpt were constructed, and used to transfect two established cell lines of mouse origin, NIH3T3 cells and m5S cells. After transfection, most NIH3T3 cells, which are resistant to mycophenolic acid, showed phenotypes characteristic of neoplastic transformation, whereas no mycophenolic acid-resistant m5S cells showed these phenotypes; integration of functionally intact v-ras^H in immortalized murine cells is not sufficient for neoplastic transformation in m5S cells. The resistance to the transformation was probably due to a lower level of the v-ras^H gene transcripts in m5S cells.

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Amplified c-myc oncogene was found in the DNAs of 2 of 11 human stomach cancers transplanted into nude mice; the amplification was 8- to 10-fold in one tumor and 13-to 15-fold in the other. Both tumors in which the c-myc oncogene was amplified were poorly differentiated adenocarcinomas, but there was no clear-cut correlation between the histological types or growth rates of the tumors and amplification of the c-myc oncogene. No amplification of the c-myc gene was detected in DNAs from 4 cultured stomach cancer cell lines, 19 primary stomach cancers or 11 metastases to lymph nodes from human stomach cancers.

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The intracellular structure and expression of integrated hepatitis B virus (HBV) DNA in the hepatoma tissue #1707 obtained from an 11-year-old boy were studied. It was found that most of the HBV genome was present in the #1707 DNA. Virus-specific 21S mRNA was also demonstrated by blot hybridization. This is the first direct evidence for the expression of the integrated viral genome in human hepatoma tissue.

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A protein p40^x was identified as a product encoded by frame IV in the pX region of human T-cell leukemia virus type I. Sera from patients with adult T-cell leukemia contained antibodies against p40^x, indicating its expression in vivo. The occurrence of splicing to form pX mRNA is proposed and the possible significance of p40^x is discussed.

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A 41-kilodalton protein was detected in four human T-cell leukemia virus type I (HTLV-I)-infected cell lines, a 68-kilodalton glycoprotein in MT-2 cells, and a 38-kilodalton protein in an HTLV-II-infected cell line by using antibody against a synthetic dodecapeptide, a portion of the polypeptide deduced from the nucleotide sequence of the X regions of HTLVs.

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12-O-Tetradecanoylphorbol-13-acetate (TPA), a potent promoter of mouseskin carcinogenesis, was tested for possible tumor-enhancing effects on urinary bladder carcinogenesis using the heterotopically transplanted bladder (HTB) model. Weekly administration of TPA at 1.0μg/week to N-methyl-N-nitrosourea-initiated HTBs did not increase tumor incidence, but instead, resulted in a significantly high incidence of nodulopapillary hyperplasia, an early neoplastic lesion, suggesting possible tumor enhancement by TPA. In addition, administration of a high dose of TPA with or without a carcinogen treatment led to the development of numerous finger-like epithelial projections on the luminal surface of the HTBs. Evidence indicates that epithelial projections are formed as a result of proliferation of intermediate cells. Whether these structures evolve into true neoplastic lesions is at present unknown.

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The effects of three sweeteners, sodium saccharin, aspartame and stevioside, on urinary bladder carcinogenesis in rats initiated by N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) were evaluated. Male F344 rats were given 0.01% BBN in their drinking water for 4 weeks and then the test sweeteners in their diet for 32 weeks. All surviving rats were sacrificed after 36 weeks, and examined histologically. Treatment with sodium saccharin significantly increased the incidence and extent of preneoplastic lesions, papillary or nodular (PN) hyperplasia, in rats treated with BBN for 4 weeks. Administration of 5% aspartame or 5% stevioside in the diet did not, however, affect the incidence or extent of PN hyperplasia in BBN-treated rats. No preneoplastic or neoplastic lesions of the urinary bladder were observed in rats treated with the test sweeteners only. The results with sodium saccharin were consistent with those in our previous experiments. The data also suggest that aspartame and stevioside do not promote bladder carcinogenesis.

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The promoting effects of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and sodium L-ascorbate on two-stage carcinogenesis initiated with methylnitrosourea (MNU) in F344 male rats were investigated. Animals were given injections of MNU (20mg/kg ip) twice a week for 4 weeks, and then basal diet containing 2% BHA, 1% BHT or 5% sodium L-ascorbate for the next 32 weeks. Administration of BHA, BHT or sodium L-ascorbate in the diet significantly increased the incidences per group and numbers per rat of papilloma and papillary or nodular hyperplasia of the urinary bladder, and BHA and BHT also increased the number of cancers per rat. Furthermore BHA significantly increased the incidences of cancer and papilloma in the forestomach of rats initiated with MNU, whereas treatment with BHA alone was associated with papilloma but no carcinoma development in the rat forestomach. The incidence of adenoma, but not adenocarcinoma, of the thyroid was significantly increased by treatment with MNU plus BHT. These results show that BHA, BHT and sodium L-ascorbate have promoting activities on urinary bladder carcinogenesis in rats initiated with MNU, and that BHA also has a promoting effect on forestomach carcinogenesis after initiation with MNU.

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Massive abdominal enlargement was observed at relatively high incidence in two species of fish kept in two public aquariums for several years. Three seminomas, one dysgerminoma and two fibromas were found in 14 largemouth bass, Micropteras salmoides, kept in a public aquarium for over 80 months. Four seminomas and one nephroblastoma were found in 24 Japanese dace (ugui), Tribolodon hakonensis, kept for more than 57 months in two different aquariums. The seminomas in M. salmoides showed rapid growth, and the affected fish died within a few months. At necropsy, a single large tumor, measuring 10.5-12.0cm, was found in the abdominal cavity. The seminomas in T. hakonensis were single or multiple tumors, measuring 2.0-4.5cm in diameter. Histologically, these seminomas were composed mainly of a typical germ cells similar to those in human seminomas or embryonal carcinomas. A nephroblastoma in one T. hakonensis showed extensive metastases to various organs. The cause of these tumors is unknown, but the prolonged longevity of fish kept under artificial conditions may have enhanced their development.

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Spontaneous tumors of the nervous system and associated organs and/or tissues in 346 male and 346 female F344/DuCrj rats and 200 male and 177 female Slc: Wistar rats were examined. The main neurogenic tumors observed were gliomas and neurinomas, which were detected in both strains of rats. Out of 7 gliomas, 6 were found in the brain and 1 in the spinal cord, and out of 4 neurinomas, 2 were in the trigeminal nerves and the other 2 were in the spinal nerves. In addition, other types of tumors (2 granular cell tumors in the brain, 1 pinealoma, 3 ganglioneuromas in the adrenal gland, 1 undifferentiated carcinoma in the nasal cavity and 1 chordoma in the posterior neck region) were observed.

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The clonal origin of spontaneous multiple mammary tumors in mice was examined. For this purpose, hybrid female mice (Pgk-1^b/Pgk-1^a), F₁[SHN(Pgk-1^b)×C3H/He (Pgk-1^a)], with X-chromosome inactivation mosaicism with regard to the phosphoglycerate kinase (PGK)-1 isozyme together with a high incidence of spontaneous mammary tumors were constructed. Thirty-seven of 45 mammary tumors (82%) in mosaic mice had a single phenotype of PGK, indicating monoclonal origin. The multiple mammary tumors formed in these mice varied in PGK type, indicating independent cellular origins.

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The mode of interaction of deoxycholate (DOC) or lithocholate (LC) with F344 rat colon was examined by measurements of uptake, ³¹P nuclear magnetic resonance (NMR) spectroscopy and observation of morphological changes. DOC as well as LC was taken up by the colon in a nonsaturable manner with respect to concentration and time, up to 30 min. None of several metabolic inhibitors reduced the uptake of the bile acids, nor did pretreatment of colon segments with chloroform-methanol (2:1, (v/v), heat or trypsin. Further, the bile acids were not transported by the colon against concentration gradients, and they were bound to both the mucosa and serosa equally. From these findings, it is concluded that the bile acids are transported in a passive manner, and no specific receptor for them is contained in colonic mucosa. The uptake of the bile acids by the colon varied with temperature and was related to the fluidity of the colonic membranes. The extent of uptake of dehydrocholate and taurocholate, which do not induce ornithine decarboxylase (ODC) activity, was almost the same as that of LC. The ³¹P NMR spectra of the colonic mucosal cells indicated that the proportion of the bilayer structure is increased by 0.5mM DOC. Among a variety of bile acids examined, the extent of membrane alteration was in parallel with the extent of ODC induction. Treatment of the colonic mucosa with 0.5mM DOC caused marked degeneration of the surface but not the deeper layers of the mucosa. Thus, physiological concentrations of bile acids influence the membrane organization of the colonic mucosa in a nonspecific manner that is possibly related to the tumor-promoting activity.

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The reactivity of α-fetoprotein (AFP) with concanavalin A (Con A) and Lens culinaris agglutinin (LCA) was studied by crossed immuno-affinoelectrophoresis of the serum samples of 146 patients from three groups (groups I, II and III). Fifty-one patients with benign liver diseases were included in group I, 83 patients with hepatocellular carcinoma in group II, and 12 patients with carcinoma metastatic to the liver from digestive organs in group III. In group I, the percentage of Con A-reactive species of AFP was high (97±5%, mean±SD), but that of LCA-reactive species was very low (3±5%). The percentage of LCA-reactive species of AFP in group II (45±33%) was higher than that in group I (P<0.001), while the Con A binding pattern of AFP in this group, as demonstrated by immuno-affinoelectrophoresis, was similar to that of group I. The percentage of Con A-reactive species of AFP in group III (55±24%) was much lower than that in group II (97±5%) (P<0.001). The above results indicate that measurement of the reactivity of AFP in serum samples with Con A and LCA is useful for the differentiation of AFP species which are found in association with benign liver diseases, hepatocellular carcinoma and carcinoma metastatic to the liver.

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The activities of ribonucleotide reductase and thymidine kinase, and the thymidine incorporation rate were measured in 16 cultured human hematologic malignant cell lines with different cell proliferation rates. Thymidine kinase activity was significantly higher in myeloid and monocytoid cell lines than in other cell lines, but ribonucleotide reductase activity presented as CDP reductase activity was similar in the different cell lines. The ratio of thymidine kinase to CDP reductase activity was high in monocytoid cell lines. A close correlation was found between the cell proliferation rate and CDP reductase activity, but not thymidine kinase activity or the thymidine incorporation rate. The ratio of thymidine kinase to CDP reductase activity was high in slowly growing cell lines and low in rapidly growing cell lines. These results indicate that in cultured human malignant cells a high potential for proliferation may depend mainly on the de novo pyrimidine pathway of DNA biosynthesis.

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Spleen cells from C57BL/6 beige mouse showed significantly lower cytotoxic T lymphocyte (CTL) generation in vitro against allogeneic target cells as compared with spleen cells from the wild type, whereas the heterozygous littermate showed a response similar to that of the wild type. In contrast, the responsiveness of beige spleen cells in the mixed lymphocyte reaction against allogeneic stimulator cells was in the normal range, suggesting that beige spleen cells recognize allogeneic stimulator cells to the same extent as spleen cells from normal mouse, resulting in a significant proliferation. The addition of interleukin 1 (IL-1)-containing supernatant from lipopolysaccharide-stimulated J774.1 cells to the culture of spleen cells from beige mouse stimulated with allogeneic cells restored the impaired CTL generation in a dose-dependent manner. The molecules responsible for restoration of the impaired CTL response co-migrated with IL-1 on gel filtration. The addition of purified interleukin 2(IL-2) also augmented the induction of CTL from beige spleen cells. However, the magnitude of augmentation by IL-2 was appreciably lower than that of augmentation by IL-1. These results suggest that the role of IL-1 in the induction of CTL is not only to provide a signal for activated amplifier T cells to release IL-2, but also to magnify otherwise low responsiveness of CTL-precursors and/or CTL-helpers. Moreover, intraperitoneal injection of IL-1 without allo-antigenic stimulation was able to restore the in vitro CTL responsivity to allo-antigen but not the natural killer cell activity, indicating that IL-1 has a therapeutic potential in vivo for preferentially correcting impaired CTL generation associated with beige mutation.

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