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

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

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

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

BACKGROUNDBreast cancer has become one of the most common malignant tumors among females over the past several years. Breast carcinogenesis is a continuous process, which is featured by the normal epithelium progressing to premalignant lesions and then to invasive breast cancer (IBC). Targeting premalignant lesions is an effective strategy to prevent breast cancer. The establishment of animal models is critical to study the mechanisms of breast carcinogenesis, which will facilitate research on breast cancer prevention and drug behaviors. In this study, we established a feasible chemically-induced rat model of premalignant breast cancer.

METHODSFollowing the administration of the drugs (carcinogen, estrogen, and progestogen) to Sprague-Dawley (SD) rats, tumors or suspicious tumors were identified by palpation or ultrasound imaging, and were surgically excised for pathological evaluation. A series of four consecutive steps were carried out in order to determine the carcinogen: 7,12-dimethylbenzaanthracene (DMBA) or 1-methyl-1-nitrosourea, the route of carcinogen administration, the administration period of estrogen and progestogen, and the DMBA dosage.

RESULTSStable premalignant lesions can be induced in SD rats on administration of DMBA (15 mg/kg, administered three times) followed by administration of female hormones 5-day cycle.

RESULTSwere confirmed by ultrasound and palpation.

CONCLUSIONUnder the premise of drug dose and cycle, DMBA combined with estrogen and progestogen can be used as a SD rat model for breast premalignant lesions.

9,10-Dimethyl-1,2-benzanthracene ; Animals ; Breast Diseases ; chemically induced ; Disease Models, Animal ; Female ; Mammary Neoplasms, Experimental ; chemically induced ; Rats ; Rats, Sprague-Dawley

Cancer chemoprevention can be defined as prevention or intervantion of cancer by the administration of one or chemical entities, either, either as individual drugs or as naturally occurring constituents of the diet. The name capsaicin(trans-8-methyl-N-vanillyl-6-nonenamide) was given by Thresh in 1848, and capsaicin is a primary pungent and irritating princple present in red peppers which are windely used as spices in korean food. The inhibitory effect of capsacin on stomach or skin cancers had been reported in lots of animal studies, but there were few reports In offal cancer carclnogenesls. This study is aimed to see the effect of capsalcln upon DMBA induced cancer of the buccal pouch in hamsters. In thls study, 87 Golden Syrian hamsters, weighing about 80-90g, were used and divided into 5 group : normal group (n=2)-untreated : control group(n=15)-DMBA painted : experimental group I(n=23)-capsaicin(10 micromol/2ml) and DMBA painted ; experimental groupII(n=23)-capsaicin administered and DMBA painted ; experimental group III(n=24)-administered and patinted. DMBA painted. According to groups, the animals were sacrificed at 5, 8, 11, 14, 17 week. Microscopic examination was done and BrdUrd labeling Index was calculated. The results are as follows : 1. According to gross examination, the leukoplakia at 5 week and the papilloma at 8 week were shown in the experimental group I, III. Those feature were appeased rapider than those of the control and expefimental group II. 2. According to gross examination, the exophytic tumorous lesions were shown in the control and all of the experimental groups from 14week, but the features of the control group were severer than those of the experimental groups. 3. According to histopathologic features, the papilloma was shown in all of the experimental group except the control group at 8 week 4. Histologically, the features of the control group were severer than those of the experimental groups from 14 week and there were similar features among the experimental group I, II, III at 17 week 5. At 8 week, BrdUrd labeling index of experimental group I, III were than that of control group and it was statistically significant (p<0.05) 6. The BrdUrd labeling index of experimental group III from 11week, experimental group I from 14week, experimental group II from 17 week were lowed than that of the control group respectively and It was statistically significant(p<0.05) 7. In the distribution of the BrdUrd labeled cells, BrdUrd was more significant in the basal and parabasal cell in dysplatic changes, but in carcinoma in situ, BrdUrd showed a irregular arrangement throughout the whole thickness of the tumor epithelium According to the abone results, the irritating property of the capsaicin accelerated the carcinogenesis in early phase, but the inhibitory effect was shown from carcinoma in situ phase. So the chemopreventive effect of the capaicin which is a major ingredient of red pepper can be expected. However, the further studies including the amount and method of capsaicin administration for preventive effect of oral cancer, should be followed.
9,10-Dimethyl-1,2-benzanthracene* ; Animals ; Capsaicin* ; Capsicum ; Carcinogenesis ; Carcinoma in Situ ; Chemoprevention ; Cricetinae* ; Diet ; Epithelium ; Leukoplakia ; Mesocricetus ; Mouth Neoplasms ; Paint ; Papilloma ; Skin Neoplasms ; Spices ; Stomach ; Wind

OBJECTIVETo study the immunotoxicity induced by 9,10-dimethyl-1,2-benzathrancene (DMBA) in metallothionein gene-knocked-out mice [MT(-/-)] as compared with that in wild-type mice [(MT(+/+)].

METHODSFemale mice were treated with 25 mg/kg and 50 mg/kg of DMBA i.p., respectively and immunized with sheep red blood cells (SRBC) i.v. on the following day and rechallenged by injection of SRBC via footpad s.c. on the fourth day post-immunization. Humoral and cell-mediated immune function was assessed by the number of spleen IgM antibody plaque formation cells (PFC) to SRBC and cell-mediated delayed-type hypersensitivity (DTH) measured by footpad swelling thickness.

RESULTSAfter treatment with 25 mg/kg DMBA, a decrease in weight of their spleen and thymus and PFC/spleen were observed in MT(-/-) mice, while only decrease in thymus weight of MT(+/+) mice. The humoral function was suppressed by 72% in MT(-/-) mice. No obvious change in cell-mediated immune function was observed both in MT(-/-) and MT(+/+) mice. Both humoral and cell-mediated immune function were suppressed more severe (91%) in MT(-/-) mice treated with 50 mg/kg DMBA than those treated with 25 mg/kg DMBA (72%). DTH was not altered by DMBA in MT(+/+) mice. The weight of their spleen and thymus decreased and humoral immune function suppressed in MT(+/+) mice, but these changes were significantly less severe. No obvious suppression of cell-mediated immune function was observed in MT(+/+) mice.

CONCLUSIONTheir humoral and cell-mediated immune function was more susceptible to being suppressed by DMBA in MT(-/-) mice, indicating that MT could protect their immune function from damage caused by DMBA.

9,10-Dimethyl-1,2-benzanthracene ; toxicity ; Animals ; Immunity ; drug effects ; Metallothionein ; physiology ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Organ Size ; drug effects