No abstract available.
9,10-Dimethyl-1,2-benzanthracene* ; Tocopherols*

No abstract available.
9,10-Dimethyl-1,2-benzanthracene* ; Carcinogenesis* ; Hyperbaric Oxygenation* ; Submandibular Gland*

No abstract available.
9,10-Dimethyl-1,2-benzanthracene* ; Animals ; Breast Neoplasms* ; Breast* ; Estrogens* ; Rats*

No abstract available.
9,10-Dimethyl-1,2-benzanthracene ; Animals ; Rats ; Submandibular Gland

PURPOSE: This study was carried out to investigate the effect of irradiation on the expression of proliferating cell nuclear antigen (PCNA) and apoptosis induction during the carcinogenesis in hamster buccal pouch. MATERIALS AND METHODS: Three months old Syrian golden hamsters were divided into control and 2 experimental groups. Hamsters in control group were left untreated on buccal pouchs. Twenty four hamsters were treated with 0.5% DMBA tri-weekly on the right buccal pouch. Forty eight hamsters were treated with 0.5% DMBA tri-weekly and irradiated with the dose of 5 Gy and 10 Gy at 6, 9, 12, 15 weeks after DMBA application. Resected buccal pouches were sectioned and examined for potential expression pattern of PCNA and apoptosis. RESULTS: The PCNA index was increased with the stages of buccal pouch epithelium carcinogenesis except the hyperplasia stage in control group (p<0.05). The irradiation did not effect on the PCNA index in the dysplasia and the carcinoma in situ stage, but in the hyperplasia stage, the PCNA index was increased with 10 Gy radiation and decreased in the carcinoma stage (p<0.05). The apoptotic index was significantly decreased from the carcinoma in situ stage and the lowest in the carcinoma stage. The apoptotic index was significantly decreased in the hyperplasia and dysplasia stage with the 5 Gy irradiation and significantly increased only in the carcinoma stage with the 10 Gy irradiation (p<0.05). CONCLUSION: The PCNA and apoptotic index were varied according to the irradiation period and dosage in each carcinogenesis stage.
9,10-Dimethyl-1,2-benzanthracene* ; Animals ; Apoptosis* ; Carcinogenesis* ; Carcinoma in Situ ; Cricetinae* ; Epithelium ; Hyperplasia ; Mesocricetus ; Proliferating Cell Nuclear Antigen* ; Radiation Dosage

PURPOSE: To understand the morphologic and molecular changes in carcinogen-induced breast tissues, DMBA (10-dimethy1-1,2 benzanthracene) was administrated in Sprague- Dawley female rats. MATERIALS AND METHODS: At 50 days of age, all experimental rats were given 20 mg DMBA by gastric intubation. Until the seventh week after DMBA administration, six rats were sacrificed every week, thereafter all tumors found during 20 weeks were removed every week. The morphologic changes were evaluated in routinely processed sections stained with H-E and with anti-smooth muscle actin antibody. Mutation of Ha-ras codons 12 and 61 was examined by ARMS (amplification refractory mutation system) method in frozen tissues. RESULTS: The epithelial cell proliferation of terminal end buds began 2 weeks after DMBA treatment and progressed to the 6th week, resulting in microscopic malignant tumor in one of the 7th weeks rats. The tumors were developed in 43 of 62 rats (69.4%); 8 benign lesions in 4 rats and 72 malignant tumors in 39 rats. Mutations in the 12th and 61th codon of Ha-ras gene were respectively found in 29.7% and 2.7% of preneoplastic breasts, 25% in benign lesions, 2.6% and 31.6% of malignant tumors. CONCLUSION: DMBA treatment in rats induced epithelial proliferation, then benign and malignant tumors through Ha-ras gene mutation, especially in codon 61 leading to cancer.
9,10-Dimethyl-1,2-benzanthracene* ; Actins ; Animals ; Arm ; Breast ; Codon ; Epithelial Cells ; Female ; Genes, ras ; Humans ; Intubation ; Rats*

Glioma derived from the neural ectoderm is the most common brain tumor and is of great damage to human health among all lethal tumors. Scientists have been trying their best to find new methods and develop new drugs to treat glioma in recent years. The animal glioma model is of great importance to the research. Researchers have developed many animal glioma models, like the rat and mouse model. Now we are trying to develop a new zebrafish glioma model, which has much more advantages and fewer disadvantages than the traditional models in regard to gene mutation, chemical induction, and xenografts. Establishing a glioma model in zebrafish is feasible and would be of great use to patients with this common brain tumor.
9,10-Dimethyl-1,2-benzanthracene ; Animals ; Brain Neoplasms ; chemically induced ; genetics ; pathology ; Carcinogens ; Disease Models, Animal ; Genome ; Glioma ; chemically induced ; genetics ; pathology ; Mutagenesis, Insertional ; Mutation ; Neoplasm Transplantation ; Zebrafish ; genetics

PURPOSE: The incidence of salivary gland tumor is approximately 2% among all head and neck tumors, of which malignant cases account for only about 5%. Much research has been performed in order to clarify the mechanism of oncogene activation, however salivary gland tumors remain understudied. We performed this study in order to characterize the ras gene in these tumors. MATERIALS AND METHODS: We treated white rats with 7, 12-dimethylbenz[a]anthracene (DMBA) and confirmed the occurrence of salivary gland tumors after ten to thirty weeks. Isolated genomic DNAs from tumor tissues were added to NIH 3T3 cells. In order to detect Ha-ras mutations, we performed a two-step PCR-RFLP and 7analyzed the mutated sequences. RESULTS: We induced salivary gland tumors by DMBA treatment in white rats. Isolated DNAs from the tumor tissues transformed the NIH 3T3 cells. Point mutations were observed in codons 12 and 61 of the Ha-ras oncogene. The total frequency of point mutations was 13.9% in DMBA-induced salivary gland tumors in rats. CONCLUSION: Our results demonstrate that a variety of cancers ras oncogene mutations were also found in salivary gland tumors. We confirmed that a point mutation of the Ha-ras oncogene in a DMBA-induced salivary gland tumor occurs at a frequency of 13.9%.
9,10-Dimethyl-1,2-benzanthracene* ; Animals ; Codon ; DNA ; Genes, ras* ; Head ; Incidence ; Neck ; NIH 3T3 Cells ; Oncogenes ; Point Mutation ; Rats* ; Salivary Glands*

The inhibitory effect of selenium, vitamin E, and BHA on DMBA-induced mammary tumorigenesis in rats was investigated. Dietary vitamin E (200 IU/Kg diet) alone could not reduce the tumor incidence at 25 weeks after DMBA administration (10mg DMBA/rat) when selenium was deficient. Selenium supplementation (2ppm in drinking water) to rats fed a practical diet (0.17 ppm Se) reduced the tumor incidence to 14.3% from 75% at 27 weeks after DMBA administration. Dietary supplementation of BHA (0.75%) also reduced the incidence of DMBA-induced mammary tumor to 42.9% at 27 weeks after DMBA-treatment. Rats fed a diet deficient in both selenium and vitamin E contained significantly lower glutathione peroxidase activity and higher malondialdehyde in muscle. However, supplementation of selenium or BHA to the rats fed a practical diet did not alter the malondialdehyde content and glutathione peroxidase activities in muscle, skin and mammary gland. Dietary selenium increased the tissue selenium level. DMBA-induced mammary tumorigenesis was reduced by antioxidants tested but the anticarcinogenic effect of selenium or BHA seems to be independent of glutathione peroxi-dase activity.
9,10-Dimethyl-1,2-benzanthracene ; Animal ; Antioxidants/pharmacology* ; Butylated Hydroxyanisole/pharmacology ; Female ; Mammary Neoplasms, Experimental/pathology* ; Rats ; Selenium/pharmacology ; Vitamin E/pharmacology

The purpose of this study is to evaluate the prognostic significance of argyrophilic nucleoalr organizer regions (AgNORs) and proliferating cell nuclear antigen (PCNA) by using DMBA hamster buccal pouch carcinogenesis which provides a good experimental model in reproducing steps from precancerous lesions to invasive squamous cell carcinomas. The buccal pouches of 50 Syrian hamsters were applied with 0.5% DMBA in mineral oil three times a week to reproduce various lesions from precancerous ones such as hyperkeratosis or epithelial dysplasia to invasive squamous cell carcinomas. Their sections were stained with H & E, and silver colloid, and processed immunohistochemically by being applied with monoclonal antibody to PCNA. The histopathologic examainations were done and the counts of AgNORs were evaluated. The PCNA labelling indices on each lesions were evaluated. The correlation between histopathological grades and counts of AgNORs or PCNA labelling indices were evaluated. The number of AgNORs was 2.22+/-0.22 in control group, 3.46+/-0.72 in carcinoma in situ (CIS), 3.78+/-0.63 in squamous cell carcinoma (SCC), respectively. AgNORs significantly increased in severe epithelial dysplasia, CIS, and SCC compared with normal tissue (P<0.05). The PCNA Labeling Index (LI) was 39.47+/-6.68% in control group, 79.61+/-4.14% in CIS, and 85.43+/-6.25% in SCC, respectively. PCNA LI also significantly increased in epithelial dysplasia, CIS, and SCC compared with normal tissue (P<0.05). The number of AgNORs, AgNOR area, and PCNA LI slightly increased in the advancing front than in the center of SCC, but, it was not statistically significant. It appeared that there were a good correlation between the number of AgNORs and PCNA LI (Pierson correlation coefficient : 0.649, P<0.001). These results suggested that the number of AgNORs and the PCNA LI could be useful markers for evaluating the risk of malignant transformation and prognosis of SCC. It was thought that the clinical usefulness of these markers should be verified by using human tissue specimens.
9,10-Dimethyl-1,2-benzanthracene ; Animals ; Carcinogenesis* ; Carcinoma in Situ ; Carcinoma, Squamous Cell ; Colloids ; Cricetinae* ; Humans ; Mesocricetus ; Mineral Oil ; Models, Theoretical ; Prognosis ; Proliferating Cell Nuclear Antigen* ; Silver