The presence of activated oncogenes in several rat hepatocellular carcinomas induced by 2-amino-3-methylimidazo [4, 5-f]quinoline (IQ) was examined by NIH 3T3 cell transfection assay and Southern blot analysis. In one tumor, IQ4, rat H-ras-1 and another oncogene that did not belong to the ras family were found to be activated.

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Newborn SD rats were inoculated intracranially with JC virus (Tokyo-1), a human polyomavirus, isolated from the autopsied brain of a patient with progressive multifocal leukoencephalopathy. Twenty-one to 61 weeks later, 20 of 27 rats developed tumors in the cerebrum, but not in the cerebellum. The undifferentiated neuroectodermal nature of the tumors was histologically, immunohistochemically and ultrastructurally confirmed.

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Quantitation of acquired immune deficiency syndrome (AIDS)-related virus-bearing cells was analyzed by a newly developed plaque-forming assay. A chemically adherent HTLV-I-positive MT-4 cell monolayer was used as the cytolytic responder cells to the AIDS-virus infection. When AIDS-virus-infected cells (Molt-4/HTLV-III, H9/HTLV-III, and CEM/LAV) were seeded with MT-4 cells, plaques were observed corresponding to the number of HTLV-III-positive cells plated. Plaque formation was inhibited by the addition of anti-HTLV-III-positive serum (neutralizing antibody) to the agarose medium. These data suggest that this plaque-forming assay technique should be useful for the quantitative analysis of AIDS-virus-bearing cells.

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By transfecting cloned DNA fragments of canine adenovirus type 1, a novel transforming region of mammalian adenovirus was demonstrated inside the viral genome. Besides the left-end SmaI-D fragment (left 17.2%), an internally located SmaI-E fragment (17.2-28.7%) of canine adenovirus type 1 was found to transform primary rat kidney cells.

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An interspecific cell hybrid was constructed between a temperature-sensitive mutant cell line of mouse FM3A cells (FT20-M6, a 6-thioguanine-resistant derivative of tsFT20) that has heat-labile DNA polymerase α and a human diploid fibroblast derived from a patient with the fragile X syndrome. After extensive segregation of the human chromosomes, a hybrid clone, named M6-39-11, was obtained that contained an X chromosome as the only human chromosome, was able to grow at the nonperis sissive temperature and contained human DNA polymerase α. These data strongly suggest that the functional human gene for DNA polymerase α is located on the X chromosome.

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On ingestion of fried ground beef by humans, the urinary mutagenicity, as examined by the Ames test, increased rapidly and then decreased during a period of 12hr to resume the original low level. The excreted mutagens were shown to differ from 2-amino-3, 8-dimethylimidazo [4, 5-f]quinoxaline, the major mutagen in the cooked beef.

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The present study was undertaken to assess the mammary carcinogenic effect of low doses of fission and thermal neutrons in female W/Fu rats. Only 2 of 62 (3.2%) rats exposed to various doses of fission radiation alone developed mammary tumors (MT) in a 12-month observation period, whereas 21 of 63 (33.3%) similarly irradiated rats developed MT if further treated with prolactin; the lowest effective dose was 4.1 rad, which contained only 1.7 rad of fission spectrum neutrons with an average energy of 2.0MeV. The long survival of radiation-initiated potentially malignant cells was suggested by the observation that excess numbers of MT developed in irradiated rats in whom prolactin treatment was started as late as 12 months after irradiation. The negligible contribution of gamma-rays, one component of the reactor radiations, to the rat mammary carcinogenesis was proven by a simulation experiment with ⁵⁰Co gamma-rays. Thermal neutrons with an average energy of 0.025eV were less effective than fission neutrons. The rat mammary carcinogenic effects of 180 kVp X-rays, 14.1MeV fast neutrons, 0.025eV thermal neutrons and 2.0MeV fission neutrons were estimated in such a way as to compare the dose of each radiation that gave an MT incidence of 40% of that in irradiated, prolactin-treated rats. The efficiency of fission spectrum neutrons is much higher than those of other radiations; the relative biological effectiveness (RBE) of fission spectrum neutrons was 17.8 against X-rays. Based on these findings, the relevance of animal data to tumor induction in atomic bomb survivors is discussed.

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The carcinogenicity of a potent mutagen, 1, 6-dinitropyrene (1, 6-DNP), was examined by intratracheal instillation into non-inbred Syrian golden hamsters of both sexes. Animals were treated with 0.5mg of 1, 6-DNP suspended in 0.2ml of saline intratra-cheally once a week for 26 weeks. Lung carcinomas developed in experimental weeks 20-48 in 100 and 90%, respectively, of the male and female hamsters treated with 1, 6-DNP. Besides lung carcinomas, myeloid leukemias developed in 60% of both males and females treated with 1, 6-DNP. No tumors were found in control hamsters.

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The effect of dietary p-methoxybenzeneselenol, a new organoselenium compound, on azoxymethane(AOM)-induced hepatocarcinogenesis was examined in female F344 rats. Semipurified diets containing 0 and 5ppm p-methoxybenzeneselenol were fed to the rats, starting at 5 weeks of age until one week after the carcinogen treatment. At 7 weeks of age, all animals except the vehicle-treated controls were given weekly sc injections of AOM (15mg/kg body weight, 3 times). At 34 weeks after the last AOM treatment, the liver neoplasm incidence and liver tumor multiplicity as well as the incidence of altered liver cell foci were significantly lower in AOM-treated rats fed the diet containing 50ppm p-methoxybenzeneselenol (tumor incidence 19%, tumor multiplicity 0.45/rat, foci incidence 3.47/cm²) than in AOM-treated animals fed the diet without p-methoxybenzeneselenol (tumor incidence 66%, tumor multiplicity 2.24/rat, foci incidence 12.08/cm²). These results indicate that dietary p-methoxybenzeneselenol at a dose of 50ppm inhibits AOM-induced hepatic tumorigenesis.

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The Drosophila wing spot test is fast and sensitive for detecting somatic mutation and recombination. Nine heterocyclic amines, which had been identified as mutagenic constituents of cooked food by using the Salmonella/mammalian-microsome test system, were orally fed to larvae of the tester strain. All the compounds (Trp-P-1, Trp-P-2, Glu-P-1, Glu-P-2, IQ, MeIQ, MeIQx, AaC, MeAaC) showed mutagenicity in this system. The reported values of carcinogenic potency in the mouse assay for seven of the nine compounds showed an excellent correlation with mutagenic potency values obtained in the Drosophila assay, but not with those obtained in the Salmonella assay, indicating that the Drosophila short-term test is promising for quantitative pre-screening of potential carcinogens.

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By screening sera obtained from 5015 pregnant women under the care of 9 gynecology/obstetrics departments of hospitals or clinics in Nagasaki City and its surrounding areas, 187 were found to be positive for antibody against adult T-cell leukemia-associated antigen (ATLA). The prevalence of seropositive pregnant women was consistent with that of blood donors in the age group of 16 to 29 years, taken as controls. Essentially all cord blood samples (113/115) of babies born from these seropositive mothers were positive for anti-ATLA of IgG class. These IgG antibodies in the babies diminished rapidly after delivery, and were detectable only in 3 cases at 2, 3, and 5 months of ages out of 38 babies up to 21 months. None of 115 cord bloods so far tested was positive either for anti-ATLA of IgM class or for ATLA-bearing lymphocytes after short-term cultures of the rosette-forming T-lymphocytes. Two of the babies born from 38 seropositive mothers were found seroconverted between the ages of 12 and 19 months. Three out of 20 elder siblings were found seropositive at ages of 3 to 6 years. The seropositive rate in these siblings was significantly higher than that of controls. Moreover, 12 out of 13 mothers traced back from seropositive students were found seropositive. These data indicate strongly that HTLV-I is transmitted from seropositive mothers to their children as a major pathway.

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To obtain experimental support for possible milk-borne infection of human T-cell leukemia virus type-I (HTLV-I), short-term-cultured viral antigen-positive lymphocytes obtained from peripheral blood of adult T-cell leukemia lymphoma complex (ATLL) patients were inoculated into the oral cavity of two adult common marmosets (Callithrix jacchus) in amounts comparable to those of HTLV-I-carrying cells fed to a baby in the milk of seropositive mothers. One of the animals seroconverted 2.5 months after the first inoculation. Cultures of peripheral blood mononuclear leukocytes of the marmoset revealed HTLV-I antigen expression in cells, indicating the establishment of oral infection of HTLV-I in an adult marmoset. The cell number deduced to be responsible for the infection was 5.6×10⁷ cells (used in the first 2 inoculations). The results suggest that the concept of milk-borne infection of HTLV-I from a seropositive mother to her child is plausible.

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The effect of the helical conformation of DNA on the binding of antibodies to DNA-carcinogen adducts was evaluated. The efficiency of antibody binding to adducts produced in DNA by treatment with (+)-trans-7β, 8α-dihydroxy-9α, 10α-epoxy-7, 8, 9, 10-tetrahydrobenzo[a]pyrene (BPDE) was modulated by varying the winding angle of the DNA helix using heat denaturation, organic solvents, and cations. Unwinding and complete denaturation of the DNA helix increased the binding efficiency of antibodies to DNA-BPDE adducts 4- to 8-fold over that to BPDE adducts in the unperturbed double helical DNA. The antibody binding efficiency increased in proportion to the degree of unwinding of the double helix induced by dimethylsulfoxide, ethylene glycol, or glycerol. Conversely, winding of the double helix with monovalent cations (Na⁺, K⁺, Rb⁺, Li⁺, Cs⁺ and NH₄⁺) and more effectively with divalent cations (Mg²⁺, Ca²⁺, Mn²⁺, Sn²⁺ and Ba²⁺) decreased antibody binding to DNA-BPDE adducts. We suggest that the molecular orientation of BPDE adducts within helical grooves modulates adduct accessibility for binding with antibody molecules. By the opening and/or unwinding of the helix, BPDE adducts (or their immunogenic sites) partially “buried” within the grooves may be exposed to varying degrees for antibody binding. Conversely, winding of the helix shielded the BPDE adducts from antibody recognition and binding.

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DNA polymerase activity which sedimented at about 7s in the presence of 0.5M KCl increased in cultured kidney cells after infection with a chicken embryo lethal orphan virus, an avian adenovirus. Elevated levels of antigenic material to a monoclonal antibody specific for the large subunit of chicken DNA polymerase α were also detected in nuclei of virus-infected cells by an immunofluorescence method. Since the elevations of DNA polymerase activity and of nuclear immunofluorescence was not inhibited with 1-β-D-arabinofuranosylcytosine, the early viral gene(s) seems to be responsible for the induction of the synthesis and nuclear acc umulation of DNA polymerase α.

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For the purpose of characterizing the nature of the phorbol ester receptor on intact cells, the effects of acylglycerols and phospholipids, which are known as activators of protein kinase C, on the binding of ³H-phorbol dibutyrate to Friend erythroid leukemia cells (FLC) were examined. Even when intact cells were used, diolein inhibited the binding of phorbol ester, and the degrees of inhibition by several kinds of acylglycerols paralleled their abilities to activate protein kinase C. On the other hand, phosphatidylserine enhanced the binding. Among phospholipids tested, the order of activities for increasing the binding was almost the same as that for activating protein kinase C. These results provide support for the hypothesis that the phorbol ester receptor in intact cells is protein kinase C, and that the ability of intact cells to bind phorbol ester is affected by endogenous lipids.

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In order to clarify the relationship between human papillomavirus (HPV) and a variety of surface epithelial lesions, the presence of papillomavirus genus-specific common structural antigen (pgs-antigen) was immunohistochemically investigated in 256 cases of various tumors and tumorous lesions. The pgs-antigen was demonstrated in cases of verruca vulgaris (11/23 cases), condyloma acuminatum (13/26), adult laryngeal papilloma (3/12) and bowenoid papulosis (2/2). No pgs-antigen was observed in ordinary Bowen's disease and other hyperkeratotic skin lesions, such as keratoacanthoma and seborrheic keratosis. In uterine cervical lesions, about 15% of cervical dysplasia, most of which later developed into carcinoma in situ, contained pgs-antigen-positive koilocytotic cells. These results suggest that HPV infection is frequently present in human hyperplastic and atypical surface epithelial lesions of Japanese patients and might indicate possible association with neoplastic transformation, especially in the cervix and skin.

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Hormone receptors for estrogen (ER), progesterone (PGR) and prolactin (PRL-R) were measured in primary breast cancer tissues obtained from 214 patients at radical mastectomy. The patients were followed up at intervals of one to three months to examine the relationship between hormone receptor status and prognosis. ER status was related to PGR status but not to PRL-R status. PRL-R was more frequently detectable in pathologic stage 3 than in stage 1 & 2 (22% vs. 10%, P<0.05) whereas ER and PGR were not different between stage 1 & 2 and stage 3 groups. The influence of receptor status on prognosis was analyzed in 164 patients of stage 1 & 2 by means of the actuarial life table technique. The recurrence-free interval was not related to ER, PGR or PRL-R status. The ER-positive group was associated with significantly prolonged survival compared with that of ER-negative patients at 42 to 51 months after surgery. PRL-R positive patients had a significantly worse survival than the PRL-R negative group (P<0.05). These findings indicate that receptor status may provide useful prognostic information in patients with early breast cancer and that the lactogenic hormone may play an unfavorable role in relation to the prognosis of human breast cancer.

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A clone of murine monoclonal antibody HH 10 (IgM) was raised by fusing NS-1 myeloma cells and spleen cells of a mouse hyperimmunized with acute promyelocytic leukemia cells. Serological analysis by means of immune adherence assays showed that HH 10 reacts with immature hematopoietic cells including thymocytes and myeloid precursor cells (defined as colony-forming units in culture assays). The antibodies were not reactive to either peripheral blood cells or bone marrow cells obtained from normal individuals. Lymphoid blasts induced with phytohemagglutinin, pokeweed mitogen, or concanavalin A were also non-reactive, and all non-hematopoietic cultured cells examined were also negative. The antibodies were, however, reactive to leukemia cells in 67 cases out of 91 cases (74%) of acute leukemia. In patients with acute lymphoblastic leukemia, 43 out of 52 cases (83%) were positive and, in particular, all of 12 T-cell-type acute leukemias were reactive to HH 10. Comparison of percent HH 10 positive cells in the bone marrow of patients with acute leukemia with the results of cytological studies showed a good correlation. Analysis of sequentially collected bone marrow cells of acute leukemia patients using HH 10 revealed its usefulness for monitoring leukemia cells.

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The effect of teleocidin, a new tumor promoter, on immune responses was studied in vitro using murine lymphocytes. Teleocidin had a mitogenic and a comitogenic activity on murine lymphocytes at doses of 1-1000ng/ml. The responder cells to teleocidin stimulation were T cells. However, for the stimulation of T cells with teleocidin, Ia-positive macrophages were required as accessory cells. On the other hand, teleocidin had a suppressive activity at the same doses on the induction of hapten-reactive cytotoxic T cell response in vitro. All these results on mitogenic and immunosuppressive activity are similar to those obtained in a previous study on 12-O-tetradecanoyl phorbol-13-acetate. Thus, it is suggested that the role of tumor promoters during carcinogenesis is a potentiation of the growth of transformed cells and a suppression of the immune-surveillance mechanism.

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A serum protein was purified from normal human sera by several steps of purification, and tentatively designated as cancer-associated serum protein (CAP-135), since the content of the protein was remarkably decreased in cancer patients. The purified CAP-135 has an approximate molecular weight of 135, 000 daltons, and is composed of three subunits of 78, 000, 34, 500 and 24, 800 daltons. CAP-135 showed an isoelectric point of pH 5.5-5.8 and contained a small amount (1.38%) of neutral sugar. CAP-135 is assumed to be a modified complement C₃ on the basis that it reacted only with anticomplement C₃ in immunodiffusion assay, and one of its subunits had a molecular weight similar to that of the β-chain of human complement C₃. The ip injection of CAP-135 apparently inhibited the growth of sarcoma-180 implanted into the groin of Jcl:ICR female mice. The present results indicate that CAP-135 may be of diagnostic value.

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