Human immunodeficiency virus (HIV) was isolated from a Japanese hemophilia B patient with AIDS. This isolate, HIV[GUN-1], was infectious to several mature T-cell lines. Proteins with apparent molecular weights of 160, 55 and 25 kilodaltons were detected. Restriction enzyme cleavage patterns of the proviral genome indicated that HIV-[GUN-1] is related to but clearly different from HTLV-III or ARV-2.

View full abstract

Using the human c-erbB-2 cDNA as a probe, we applied in situ hybridization techniques to acute promyelocytic leukemia cells with a 15;17 chromosome translocation, t(15;17)(q;22;q21), and were able to localize the c-erbB-2 gene on chromosome 17 to band q12 or q21 and on the proximal side of the breakpoint in the translocation. From this finding and previous observations by others, we presume that the gene and the breakpoint are both in band q21.1 of chromosome 17. We suggest possible involvement of the c-erbB-2 gene in the development of the t(15;17)-associated acute promyelocytic leukemia.

View full abstract

The activation of proto-oncogenes in colorectal cancers in Japanese patients was studied using a mouse NIH3T3 cell transfection assay system. Of thirty-five colorectal cancers examined, one rectal cancer showed an unusually high transformation efficiency and, in this rectal cancer, the N-ras oncogene was found to be activated. Nucleotide sequence analysis of the activated N-ras showed a single G→C point mutation at the first letter of codon 13, resulting in the coding of arginine instead of glycine. This amino-acid substitution at codon 13 may be responsible for the efficient induction of transformants of NIH3T3 cells in vitro.

View full abstract

The induction of gastric tumor and intestinal metaplasia was examined in 8-week-old male JCL/SD rats exposed to localized X-irradiation of the gastric region. The animals were each given two 20Gy fractions of X-rays, with a one-week interval between fractions (total, 40Gy). Nine atypical hyperplasias (20%) and 13 adenocarcinomas (28%) in the pyloric mucosa of the glandular stomach were found in 46 animals with X-irradiation. The incidence of intestinal metaplasia was 93% in the pyloric mucosa, 50% in the fundic mucosa and 96% in both the pyloric and fundic mucosa. Type B metaplasia (intestinal metaplasia without Paneth cells) was most common and type C (intestinal metaplasia with Paneth cells) was less frequent. No gastric tumor or intestinal metaplasia appeared in non-irradiated control rats. This study shows that local X-irradiation of the gastric region induced both gastric tumor and intestinal metaplasia independently.

View full abstract

The potential tumor-promoting and -initiating activities of bile acids in the glandular stomach mucosa of F344 rats after administration by gastric intubation were studied. Taurocholic acid sodium salt at doses of 300 to 1200mg/kg body weight and glycocholic acid sodium salt at doses of 400 to 1200mg/kg body weight induced up to 100-fold increases in ornithine decarboxylase activity with maxima after 4hr and up to 10-fold increases in replicative DNA synthesis with maxima after 16-17hr in the pyloric mucosa of the stomach. Taurodeoxycholic acid sodium salt, taurochenodeoxycholic acid sodium salt and glycocholic acid also induced high ornithine decarboxylase activity, and glycodeoxycholic acid sodium salt and glycochenodeoxycholic acid sodium salt caused slight induction of ornithine decarboxylase activity, but taurolithocholic acid sodium salt did not induce ornithine decarboxylase activity at all in the pyloric mucosa of the stomach. Glycocholic acid sodium salt did not induce unscheduled DNA synthesis in the pyloric mucosa of the stomach. The present results suggest that six bile acids, but not taurolithocholic acid sodium salt, have potential tumor-promoting activities in the pyloric mucosa of rat stomach and that glycocholic acid sodium salt has no potential tumor-initiating activity in the pyloric mucosa of rat stomach.

View full abstract

Single dosage effects of the rat nude gene (rnu) on spontaneous development of epithelial thymoma, muscle atrophy and nephrotic syndrome were studied by comparing littermates of rnu/+and+/+rats on a high thymoma strain, BUF/Mna, background. Heterozygous rnu/+rats had a significantly smaller thymus than the+/+littermates at 6 weeks of age. The incidence of thymoma at 12 months of age was extremely low in the female rnu/+rats (3%) as compared with that of the +/+ rats (94%). Development of the nephrotic syndrome but not of the muscle atrophy was also suppressed in the heterozygotes. The results suggest that a recessive mutant gene, rnu, in a single dosage, interfered with critical steps of the disease processes of the thymoma and nephrotic syndrome in BUF/Mna-background rats.

View full abstract

Arylhydrocarbon hydroxylase (AHH) activity was determined in cultured human epidermal and dermal cells with and without induction by benz[a]anthracene (BA). Large inter-individual variations were found in the basal and induced AHH activities and the induction ratio. The average basal AHH activity of 29 epidermal cultures in primary culture was 3.9 units (SD, 4.2; range, 0-16.3) (one unit was defined as 1 pmol of 3-hydroxybenzo[a]pyrene formed/mg protein/hr). AHH activity was induced time- and dose-dependently by BA. The average AHH activity induced by treatment with 13μM BA for 24hr was 97.4 units (SD, 69.4; range, 2.7-216.9). The induction ratio ranged from 0.6 to 262.0, but in the majority of cultures (15 of 27 cultures, 55%) it was less than 30. The mean induction ratio and SD was 51.1±63.0. The frequency distributions of basal AHH activity and the induction ratio were asymmetrical with a right tail. No correlation was found between the AHH activity or induction ratio and the age or sex of the donors or their residential district. The basal and induced AHH activities of dermal fibroblasts were both lower than those of epidermal cells; the average basal AHH level of 14 cultures was 1.5 units (SD, 1.4; range, 0-5.2), while the average induced AHH activity was 9.6 units (SD, 6.3; range 0-23.5). The induction ratio of dermal fibroblasts was lower than that of epidermal cells, the mean and SD being 7.5±7.4 (range, 1.9-27.0). There was no correlation between the AHH activities or induction ratios in epidermal and dermal cells isolated from the same donors.

View full abstract

A new tumor cell line (SUIT-2) derived from a metastatic liver tumor of human pancreatic carcinoma has been established in tissue culture and in nude mice, and maintained for over five years. In tissue culture, the cells grew in a monolayered sheet with a population doubling time of about 38.2hr, and floated or piled up to form small buds above the monolayered surface in relatively confluent cultures. Chromosome counts ranged from 34 to 176 with a modal number of 45. Subcutaneous injection of cultured cells into nude mice resulted in tumor formation, histopathologically closely resembling the original neoplasm which had been classified as moderately differentiated tubular adenocarcinoma. Electron microscopic observation of the neoplastic cells revealed a characteristic pancreatic ductal epithelium. SUIT-2 cell line produces and releases at least two tumor markers, carcinoembryonic antigen and carbohydrate antigen 19-9, propagates even in serum-free medium, and metastasizes to the regional lymph nodes in nude mice xenografts.

View full abstract

Radiosensitizing effects of step-up heating (SUH) and step-down heating (SDH) on the tumor and skin were studied by using mammary adenocarcinoma transplanted to the foot of the C3H/He mouse. The tumor and skin responses were assessed by the tumor growth delay method and the skin reaction scoring method, respectively. Neither SDH (44°, 10min→42°, 30min) nor SUH (42°, 30min→44°, 10min) alone caused a substantial tumor or skin response. When the heat treatment was given immediately after irradiation, the thermal enhancement ratio (TER) was higher in SDH than in SUH for tumors as well as the skin. A therapeutic gain factor (TGF) of 1.2 was obtained in SUH, while no therapeutic benefit was found in SDH. SDH was applied at various times (0 to 3hr) before or after irradiation. When SDH was given before irradiation, the TER was consistently high to almost the same degree for tumors and the skin regardless of the time interval, resulting in minimal or no therapeutic gain. With SDH after irradiation, the TER for the skin decreased with increase in the time interval, while the TER for the tumor was moderately enhanced. Therefore, the TGF increased with increase in the time interval and reached 2.2 when SDH was given 3hr after radiation. SUH is slightly advantageous over SDH in terms of the TGF, and SDH should be given 3hr after irradiation when selective tumor heating is not possible.

View full abstract

The mechanism of activation of human natural killer cell activity by medullasin was studied with special reference to interferons and interleukin-2. Supernatant of lymphocytes treated with medullasin failed to stimulate natural killer cell activity when added to the lymphocyte suspension. Medullasin has been shown to enhance the natural cytotoxicity of lymphocytes stimulated with interferon-α or -β. In the present study, medullasin increased the natural killer cell activity of lymphocytes stimulated with interferon-γ. Treatment of lymphocytes with medullasin in the presence of antibodies to interferons (α, β and γ) did not alter the effect of medullasin. Medullasin also increased the natural cytotoxicity of lymphocytes stimulated with interleukin-2. The antibody to interleukin-2 failed to affect the increase of natural killer cell activity by medullasin. These results indicate that the mechanism of activation of human natural killer cell activity by medullasin is not mediated by the induction of interferons or interleukin-2.

View full abstract

Medullasin, a serine protease in bone marrow cells, has been shown to enhance human natural killer cell activity by acting directly on large granular lymphocytes. In the present report the mechanism of activation of natural killer cells by medullasin was studied by employing a single cell assay method in agar. Medullasin enhanced the target-binding capacity of lymphocytes, but the percentage of target-binding cells with dead target remained essentially unchanged. The maximum recycling capacity of natural killer cells was also increased by the treatment with medullasin. These results indicate that medullasin in granulocytes stimulates the maturation of natural killer cells with elevated recycling capacity from human large granular lymphocytes.

View full abstract

Macrophage (MA) activation by recombinant murine interferon-gamma (rMuIFN-γ) and a synthetic muramyl dipeptide derivative, N^α-(N-acetylmuramyl-L-alanyl-D-isoglutaminyl)-N^ε-stearoyl-L-lysine [MDP-Lys(L18)], was examined. The cytostatic activity of MA that had been primed with rMuIFN-γ against Lewis lung adenocarcinoma cells was augmented extensively by exposure to MDP-Lys(L18) for a minimum of 15min, though such treatment in the reverse sequence interfered with the effects of rMuIFN-γ on MA. The binding assays revealed that rMuIFN-γ bound to MA with an apparent dissociation constant (Kd) of 0.93×10^-9M (16, 000 binding molecules/cell), while MDP-Lys(L18) bound nonspecifically and was endocytosed by MA at 37°. The amount of MDP-Lys(L18) bound to the rMuIFN-γ-primed MA was significantly greater than that bound to the MA without rMuIFN-γ priming. A small increase in the amount of MDP-Lys(L18) associated with MA was also observed at 4°, but the amount was one order of magnitude less than that at 37°. The binding of rMuIFN-γ to MA was significantly suppressed by priming with MDP-Lys(L18). These results indicate that the binding of rMuIFN-γ in preference to MDP-Lys(L18) to MA is of great importance in the mechanisms of MA activation.

View full abstract

Tumor necrosis factor and interferons are multifunctional cytokines. The present studies were undertaken to investigate the biologic interactions of highly purified natural human tumor necrosis factor and highly purified natural human interferon-α, which were derived from a B cell acute lymphatic leukemia line (BALL-1 cells) sensitized with hemagglutinating virus of Japan (HVJ). Combined treatment with natural human tumor necrosis factor and natural human interferon-α synergistically inhibited the in vitro proliferation of P4788 cells derived from a human colon cancer. Flow cytometric analysis of the cell cycle of asynchronous cells indicated that target cells treated with natural human tumor necrosis factor alone accumulate in the S phase. This accumulation in the S phase of the cell cycle was augmented by combined treatment with natural human tumor necrosis factor and natural human interferon-α. The growth inhibitions appeared to be a result of arrest in the S phase of the cell cycle. Combined treatment with these cytokines had potent cytostatic and cytotoxic effects on most of the tested malignant cell lines of human epithelial origin.

View full abstract