• Korean Journal of Veterinary Research
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• v.43 no.4
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• pp.683-688
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• 2003

Caffeine (1,3,7-trimethylxanthine), a central nervous system stimulant, is contained in various foods, beverages and over-the-counter medications. Sulfadimethoxine (SDM) is one of the anti-thyroid agents and induces proliferation of thyroid capsule in two stage thyroid carcinogenesis model using N-bis(2-hydroxypropyl)nitrosamine (DHPN). In this study, we examined the effect of caffeine on fibrous proliferation of thyroid capsule in DHPN and SDM-treated rats. Five-week-old male F344 rats were given a single subcutaneous injection of DHPN (2,800 mg/kg, body weight). Starting one week thereafter, SDM (1,000 ppm in drinking water) with or without caffeine (1,500 ppm in diet) was administered for 12 weeks. All animals were autopsied and histopathological examination of the thyroid glands was performed. Thyroid follicular proliferative changes were induced in all rats treated with DHPN+SDM. In addition, the proliferation of perithyroidal fibrous tissue and pleomorphic thyroid follicular cells within the capsule were observed in DHPN+SDM treated group. Caffeine would not be related to these lesions in this experimental condition. although pentoxifylline, a methyl xanthine derivative, has an anti fibrotic effects.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.118-118
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• 2003

The influence of dietary supplementation with dehydroepiandrosterone-sulphate (DHEA-S) at 0.6% was investigated in male Syrian golden hamsters initiated by treatments with azoxymethane(AOM), and dihydroxy-di-n-propyl nitrosamine (DHPN), timed after transfer from a choline-deficient to a normal diet.(omitted)

• Environmental Mutagens and Carcinogens
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• v.11 no.2
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• pp.118-133
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• 1991

신생랫드를 이용한 다장기 발암모델의 전암단계 병변에서 간장의 GST-P 활성도와 발암 과정에 영향을 미치는 phenobarbital (PB)의 발암촉진효과 및 병리조직학적 소견을 관찰하였다. 신생랫드를 150마리 3군으로 나누어 diethylnitrosamine (DEN : 100mg/kg,i,p.), N-me-thyl-N-nitrosourea (MNU : 20mg/kg,i,p.), N-bis(2-hydroxypropyl)nirtosamine(DHPN : 0.1% D. W)을 각각 0, 3, 6 주에 투여하였다. 또한 PB (0.5% in basal diet)를 7주부터 계속 투여하여 8, 12, 20주에 경시적인 부검을 실시하였다.

• Korean Journal of Veterinary Pathology
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• v.5 no.1
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• pp.23-28
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• 2001

This study was conducted to assess the chemopreventive effects of sodium selenite in the rat medium-term multi-organ bioassay using a DMBDD model (DEN+MNU+BBN+DMH+DHPN). Seventy five,6-week-old, male SD rats were divided into 3 groups. The animals in group 1 received DEN(diethylnitrosamine,100 mg/kg bw, single i.p., in saline), MNU (N-methyl-nitrosourea,20 mg/kg bw, i.p.,4 times for 2 weeks), BBN (N-butyl-N-(4-hydroxybutyl) nitrosamine, 0.2% in drinking water for 2 weeks), DMH (1,2-dimethylhydrazine, 40 mg/kg bw, s.c., in saline.4 times (or 2 weeds), and DHPN (N-bis(2-hydroxy-pro-pal)nitrosamine,0.1% in drinking water for 2 weeks), then were placed on sodium selenite (4 ppm in drinking water) for 22 weeks from weeks 4 to 26. The animals in group 2 were given DMBDD alone. The animals in group 3 were given sodium selenite alone. Animals were sacrificed at week 12 for ACF quantitative analysis and at week 26 for tumor induction. The body weights in the group 1 were significantly decreased compared with those of group 2. The tumor multiplicities of large intestine in the group 1 were significantly decreased compared with those of group 2 (P<0.05). These results indicate that sodium selenite may have a potential as chemopreventive agents of colon carcinogenesis.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2003.10a
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• pp.118-118
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• 2003

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.339-339
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• 1994

It has been reported that Indole-3-carbinol (I3C), a naturally occurring compound In cruclferous vegetables, exerts anticarcinogenic activity In several organs In rodents. The modifying effects of I3C were therefore assessed uging a rat multi-organ carcinogenesis model. A total of 100 male Sprague-Dawley rats were divided Into 3 groups. Animals of groups 1 and 2 were sequentially treated with diethylnitrosamine (DEN; 100 mg/kg b.w., i.p.), N-methylnitrosourea (NNU; 20 mg/kg b.w., 4 times for 2 weeks, i.p), and dihydroxy-di-N-propylnitrosauine (DHPN; 0.1% In d.w. for 2 weeks) for 4 weeks (DMD treatment). Animals of groups 1 and 3 were given the diet of 0.25% I3C for 20 weeks after DMD initiation and then were given basal diet for 28 weeks. All animals were sacrificed at week 24 and 52, respectively. I3C has been clearly demonstrated promoting effects on the development of glutathione S-transferase placental form (GST-P) positive hepatic foci at 24 weeks of the experiment. And I3C also exerted promoting potential In the hepatocellular adenoma (4/14; 29%) and the adenoma (7/14; 50%) of the thyroid gland at 52 weeks of the experiment. Therefore, I3C may promote hepatocarcinogenesis and thyroid tumorigenesis in the rat multi-organ carcinogenesis model.