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: 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*

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

BACKGROUND: It has been suggested that mast cells are involved in the tumor growth and progression by production of a variety of enzymes and growth factors. They were studied in the 10-dimethyl-1,2 benzanthracene (DMBA)-induced rat mammary tumors, and evaluated in relation with the production of tryptase, chymase, and matrix metalloproteinase (MMP)-2 and MMP-9. METHODS: Preneoplastic and neoplastic breast tissues of Sprague-Dawley female rats were obtained every week after DMBA treatment for 12 weeks. Toluidine blue stain was used for the identification of mast cells. Mast cell tryptase was studied by immunohistochemistry, and chymase by esterase stain. MMP-2 and MMP-9 were measured by Western blotting. RESULTS: The numbers of mast cells in breast cancers were higher than in preneoplastic tissues, and there was a positive correlation between the numbers of tryptase-positive cells and the tumor size. MMP-9 quantity was correlated with the numbers of toluidine blue and chymase positive cells, but not with tryptase-positive cells and tumor size. Both active and inactive forms of MMP-2 and MMP-9 were identified in zymogram. CONCLUSIONS: The mast cells are increased in the DMBA-induced breast cancers, and their tryptase and chymase may play a role in tumor progression with or without participation of MMP-2 and MMP-9.
9,10-Dimethyl-1,2-benzanthracene ; Animals ; Blotting, Western ; Breast ; Chymases ; Female ; Humans ; Immunohistochemistry ; Intercellular Signaling Peptides and Proteins ; Mast Cells* ; Rats* ; Rats, Sprague-Dawley ; Tolonium Chloride ; Tryptases

OBJECTIVES: The aim of this study was to verify the promoting effect of carbamide peroxide on dimethylbenzanthracene (DMBA)-induced carcinogenesis in the hamster buccal pouch, in order to reduce the period of latency for tumor formation. METHODS: Sixteen hamsters were randomized into two groups of eight animals each. The hamsters of the group I had their right buccal pouches treated with 0.5% DMBA and 10% carbamide peroxide teeth bleaching gel for 55 days. The animals of the group II had their right pouches treated only with DMBA. After, six animals of each group had their pouches prepared for light microscopy. Histomorphometry was performed to assess the presence of keratinization, nuclear polymorphism, pattern of invasion, number of blood vessels, and inflammatory infiltrate in the tumor front. Furthermore, the newly formed lesions were graded according the Bryne's grading system. The remaining animals had the vascular system of the pouches casted by Mercox and qualitatively analyzed by scanning electron microscopy. RESULTS: Histopathological analysis of the buccal pouches treated with DMBA and carbamide peroxide exhibited formation of squamous cell carcinoma well-differentiated with a high degree of malignancy in all pouches. The development of this neoplasm was associated with a significant increase in the number of blood vessels, presence of keratin pearls, and inflammatory infiltrate. The pouches of the group II showed inflammation, epithelial hyperplasia, dysplasia, and squamous cell carcinoma in only three right pouches. The analysis of the electron micrographs of the pouches chemically inducted with DBMA and carbamide peroxide reveled formation of a new vascular network characteristic of squamous cell carcinoma. CONCLUSION: The protocol presented here, using DMBA associated with carbamide peroxide, shortens the period of latency to produce squamous cell carcinoma in the hamster buccal pouch, decreasing the time and costs of the experiments.
9,10-Dimethyl-1,2-benzanthracene ; Animals ; Blood Vessels ; Carcinogenesis ; Carcinogens ; Carcinoma, Squamous Cell ; Cricetinae* ; Head and Neck Neoplasms* ; Hyperplasia ; Inflammation ; Microscopy ; Microscopy, Electron, Scanning ; Tooth Bleaching* ; Urea*

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

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