Search PubMed⌕ Search

Biomedical subjects

A Ito

Publications and source records attributed to A Ito.

At least 793 records · Page 44Linked to original sources
PubMed1986

X-ray-sensitive mutants of mouse mammary carcinoma cells are hypersensitive to bleomycin and hydrogen peroxide.

Radiation-sensitive mutants, SX9 and SX10, were isolated from mouse mammary carcinoma FM3A cells. The mutant SX9 complemented another radiation-sensitive strain M10 of mouse leukemia L5178Y cells, but SX10 did not. SX9 and SX10 cells were more sensitive than the wild-type cells to the lethal effects of bleomycin. The frequency of X-ray-induced mutations to 6-thioguanine resistance was much higher in SX9 cells than in the wild-type cells in the dose range up to 1 Gy, although the induced mutant frequencies were not very different between these two cell strains when compared at equivalent survival. SX9, SX10 and M10 cells were found to be far more sensitive than the respective wild-type cells to hydrogen peroxide inactivation, but the levels of catalase activity were similar among these cell strains. These mutants should be useful for cloning and identifying the human genes responsible for radiation sensitivity.

Animals↗
PubMed1986

Carcinogenicity of o-ethoxybenzamide in (C57BL/6N X C3H/HeN)F1 mice.

The carcinogenicity of o-ethoxybenzamide (CAS: 938-73-8), which is also called ethenzamide and which is widely used as an antipyretic anodyne in Japan, was examined in 298 (C57BL/6N X C3H/HeN)F1 mice. Groups of males and females were fed a diet containing 0 (control), 0.4, or 1.2% o-ethoxybenzamide for 96 weeks and sacrificed at the 100th week. Among the male mice fed the higher dose of the drug, the total incidence of liver cell tumors was 68%, with 18% of the mice developing hepatocellular carcinomas; both yields were significantly higher than those in the controls. In o-ethoxybenzamide-treated male mice the multiplicities of the hepatic cell tumors were also significantly higher than the multiplicity of the hepatic tumor in male control mice. A dose-response relationship with regard to both incidence and multiplicities of hepatic cell tumors in male mice was observed. In female mice fed o-ethoxybenzamide the incidence and multiplicities of the liver cell tumors were increased compared to those of the controls, but statistical significance was observed only in the multiplicity of tumors in mice given the lower dose. In both sexes hepatic cell tumors developed earlier than in the controls. These results show that o-ethoxybenzamide enhances the development of hepatic cell tumors in male (C57BL/6N X C3H/HeN)F1 mice.

Animals↗
PubMed1986

Relationship between gastric tumorigenesis and intestinal metaplasia in rats given x-radiation and/or N-methyl-N'-nitro-N-nitrosoguanidine.

The influence of x-radiation and N-methyl-N'-nitro-N-nitrosoguanidine [(MNNG) CAS: 70-25-7] on intestinal metaplasia and gastric tumorigenesis was examined in 5-week-old male Crj:CD(SD) rats. The animals were treated either with two 10-Gy fractions of x-rays separated by 3 days for a total of 20 Gy to the gastric region and/or with MNNG orally for 4 months. Simultaneous treatment with x-rays and MNNG (group II) and MNNG only (group IV) induced gastric tumors in the majority of the animals. Sequential treatment with x-radiation and MNNG, either x-ray 2 months prior to MNNG (group I) or MNNG 2 months prior to x-ray (group III), resulted in a lower incidence of gastric tumors as compared with the incidence after treatment with MNNG alone. The frequencies of intestinal metaplasia in the x-irradiated groups (groups I and V) were significantly higher than those in group II, III, or IV. The incidence of intestinal metaplasia and of gastric tumor was inversely proportional. These results indicate that intestinal metaplasia does not play a role in the induction of gastric tumors by MNNG.

Animals↗
PubMed1986

Induction of thyroid tumors in (C57BL/6N x C3H/N)F1 mice by oral administration of 9-3',4',5',6'-tetrachloro-o-carboxy phenyl-6-hydroxy-2,4,5,7-tetraiodo-3-isoxanthone sodium (Food Red 105, rose bengal B).

The tumorigenicity of 9-3',4',5',6'-tetrachloro-o-carboxy phenyl-6-hydroxy-2,4,5,7-tetraiodo-3-isoxanthone sodium (CAS: 632-68-8) [also called Food Red 105 (FR 105) or Rose Bengal B], which is widely used for food or cosmetic coloring in Japan, was examined in (C57BL/6N X C3H/N)F1 mice. Animals were divided into 6 groups with 50 mice in each group, and they were given solutions of 0, 0.125, and 0.5% FR 105 in the drinking water starting at 6 weeks of age and ending at 101 weeks. The mean relative thyroid weights in both sexes of mice given 0.125 and 0.5% FR 105 were significantly increased compared to those of controls. Enlarged thyroid glands were composed exclusively of colloid goiters characterized by distended follicles lined with flattened follicular cells. The male mice given 0.5% FR 105 had follicular adenomas in the thyroid gland at an incidence of 22.9%, which was significantly higher than the incidence in controls (P less than .005). Radioactive 131I uptake in colloid goiters was markedly decreased compared to that in intact thyroid glands. The results indicate that FR 105 can induce colloid goiters and thyroid adenomas in a dose-dependent manner.

Adenoma↗
PubMed1986

[Antibacterial activity of cephem antibiotics against isolates from clinical specimens at the Yokohama City University Hospital].

Minimum inhibitory concentrations (MICs) of cephem antibiotics against 405 strains belonging to 17 species of clinical isolates were investigated using the standard method of the Japanese Congress of Chemotherapy. The results obtained are summarized below. Cephem antibiotics showed weak antibacterial activities against Enterococcus sp., B. fragilis and S. marcescens. S. pneumoniae, S. agalactiae, E. coli, K. pneumoniae and P. mirabilis were susceptible to cephem antibiotics. Cephem antibiotics of the 1st and the 2nd generations showed weak antibacterial activity against Citrobacter sp. and E. cloacae, while cephem antibiotics of 3rd generation had a good antibacterial activity against these species. Cephem antibiotics of the 2nd and the 3rd generations showed high antibacterial activity against H. influenzae and indole positive Proteus group. Cefoperazone showed high antibacterial activity against P. aeruginosa. Resistance to latamoxef, ceftizoxime and cefoxitin was observed among Staphylococcus sp., while the MICs of other antibiotics against Staphylococcus sp. were fairly low. Number of strains resistant to the 3rd cephem antibiotics seems to be increasing because the 3rd generation of cephem antibiotics have been used frequently. Further investigation will be required on resistant organism to these antibiotics including beta-lactamase producing strains.

Cephalosporins↗