• Korean Journal of Veterinary Pathology
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• v.2 no.2
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• pp.95-106
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• 1998

The prevalence of primary liver carcinoma (PLC) is relatively high in Clonorchis sinensis (CS) endemic areas in Korea. PLC is a malignant tumor which can be subclassified into hepatocellular carcinoma and cholangiocarcinoma(CC). CC has been associated with clonorchiasis, but it is unclear whether clonorchiasis is associated with hepatocarcinogenesis. This experiment was designed to investigate relationships between clonorchiasis and early changes of hepatocarcinogenesis. Sixteen Sprague-Dawley rats weighing 150g were divided into two groups of 8 rats in each. All rats were fed choline-devoid(CD) diet for 4 weeks. Group 1 was given 0.015-0.020% diethylnitrosamine(DEN) as drinking water for 1 week. After one week, the rats were treated orally with 1% N-acetylaminofluorene(AAF) (5 times per week for 2 weeks). Group 2 was treated equally to group 1 except for CS infection during AAF treatment. Two rats in each group were sacrificed at 4th, 5th, 6th and 7th week of the experiment. Livers were stained with OV -6, proliferating cell nuclear antigen(PCNA) and GST-p. Results were as follows: Group 2 livers showed more oval cell proliferation in parenchyma and portal areas at the 4th, 5th, 6th and 7th weeks than did livers of group 1 (p＜0.01). PCNA was mostly localized in oval cell populations, rather than hepatocytes and biliary cells. The ratio of oval cells to hepatocytes was much higher in group 2 than in group l(p＜0.01 The ratio of hepatocytes to biliary cells is higher in group 2 than in group 1 (p＜0.05), More group 2 acidophilic foci reacted to GST-p monoclonal antibody than in the noninfected group. It appeared that CS infection promoted potentially precancerous acidophilic foci and oval cell proliferation.

• Korean Journal of Veterinary Research
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• v.40 no.1
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• pp.117-129
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• 2000

This study was carried out to examine proliferative activity and expression of c-myc oncoprotein and p2lras in normal and preneoplastic rat livers induced by an in vivo mid-term chemical carcinogenesis assay. Sixty, six-week-old male specific pathogen free Sprague-Dawley male rats were randomly divided into five groups. Group I was received a single intraperitoneal(IP) dose(200mg/kg) of diethylnitrosamine(DEN). Group 2(10 rats) was operated partial hepatectomy(PH) and Group 3 was received IP(200mg/kg) DEN, fed two weeks later with 500ppm of phenobarbital(PB). Group 4 was received IP(200mg/kg) DEN, fed two weeks later 500ppm(PB) and PH at week 3 after the onset of experiment. While group 5(20 rats) was not treated and used as a control group. All the rats were sacrificed at age 14 weeks except 10 rats from group 5 were sacrificed at the onset of experiment. Livers of all rats were examined for 5-bromo-2'-deoxyuridine(BrdU) incoporation, proliferating cell nuclear antigen(PCNA), silver-binding nucleolar organizer regions(AgNORs) counts per nucleus and expression of c-myc oncoprotein and p21ras. Both the number and area of the preneoplastic lesions were significantly(p<0.01) compared to other groups. A significant(p<0.01) increase in immunoreactive cells were detected in preneoplastic hepatocytes in Groups 3 and 4 by PCNA and BrdU immunohistochemical stain. The number of the positive cells were significantly(p<0.05) lower in normal 14-week-old rats than those of 6-week-old rats. The results showed that proliferative activity of the hepatocytes was increased by treatment with DEN, PH and PB. Meanwhile, AgNORs counts per nucleus were significantly(p<0.05) increased in the preneoplastic hepatocytes of rats in both groups 3 and 4. The expression of c-myc oncoprotein and p21ras were more readily localized within the hepatic preneoplastic lesions such as hyperplastic nodules. Especially, group 4 showed significantly (p<0.05) overexpressed levels compared to groups 1 and 3. These findings suggest that PCNA, BrdU and AgNORs are significantly increased and c-myc oncoprotein and p21ras are significantly overexpressed in hepatic preneoplastic lesions induced by mid-term carcinogenesis. So these parameters can be an effective markers for hepatic prencoplastic lesions.

• Molecular & Cellular Toxicology
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• v.4 no.4
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• pp.278-284
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• 2008

The X-linked inhibitor of apoptosis (XIAP) is a member of a novel family of inhibitors of apoptosis and has several BIR domains (BIR1, BIR2, and BIR3) and a carboxy-terminal RING zinc-finger. Since suppressionof apoptosis is fundamentally important for carcinogenesis and tumor growth, we investigated the expression and function of XIAP in DEN-induced carcinogenesis using rat model. Wistar rats were injected intraperitoneally with DEN at a dose of 50 mg/kg in twice a week for 12 weeks (Group II) and 16 weeks (Group III) followed by the recovery periods, respectively. The evaluation of DEN-induced carcinogenesis carried out the blood, RT-PCR, histopathological and western blot analysis. The level of blood chemistry including GOT/GPT, albumin, and total bilirubin were significantly exchanged comparing to control and Group I/Group II. The expression of albumin and collagen mRNA were significantly exchanged (P<0.05) in both groups. In addition, AFP mRNA expression decreased more after recovery periods than Group II. XIAP was expressed constitutively in normal rat liver as well as DEN-induced Groups I and Group II. In addition, XIAP expression increased more in Group I with 4 weeks recovery periods than Group I. However, XIAP expression shown to increase in Group lI, otherwise, it was decreased in Group II with 10 weeks repair periods. Taken together, these results suggest the alteration of XIAP expression could be involved in hepatocellular carcinogenesis.

• Korean Journal of Community Nutrition
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• v.2 no.5
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• pp.735-744
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• 1997

The effect of green tea drinking on the hepatocellular chemical cacinogenesis have been studied. Placental glutathione S-transferase(GST-P) positive foci area in a liver tissue, contents of thiobarbituric acid reactive substances(TBARS), total cytochrome P450 and glucose 6-phospphatase(G6P) activity in hepatic microsomes were investigated. Weaning Sprague-Dawley male rats were fed AIN-76A diet with deionized water or green tea infusion, Rats of CTR and CTR+ groups were provided deionized water while GTI and GTI+ groups were provided green tea instead of deionized water for the entire experimental period of 13weeks. Rats of GTP and GTP + groups had deionized water for the first 6 weeks and switched to green tea for the last 7weeks of the experimental period. CTR+, GTI +, and GTP + groups were carcinogen treated groups, Diethylnitrosamine(DEN) was injected as a single dose of 200mg/kg body weight intraperitoneally after 4 weeks of feeding. 2-Acetyla-minofluorene(AAF) was used as a carcinogen proliferater and suppled in the diets of carcinogen treated rats as 0.02% content for the last 6weeks starting from 2weeks after DEN injection. Rats were sacrificed after 13week weeks of feeding. The area and number of GST-P positive foci detected in carcinogen treated rats were decreased by green tea ingestion but when timing and duration of green tea ingestion was delayed after promotion period as in GTP + group, GST-P positive foci were not decreased as much as in GTI+ group. TBARS contents of carcinogen treated rats decreased by 13weeks of green tea ingestion but GTP groups did not show statiscally significant differences. G6P activities tended to decrease by carcinogen treatment but changes were not statiscally significant by green tea ingestion. Total cytochrome P450 contents were increased by carcinogen treatment. Thirteen weeks of green tea ingestion (GTI) also increased to total cytochrome P450 contents while 7weeks of green tea ingestion(GTP) did show any effects. These results suggest that green tea has suppressive effects on hepatocellular chemical carcinogenesis probably through the activities of antioxidant compounds. (Korean J Community utrition 2(5) : 735∼744, 1997)

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.5
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• pp.782-787
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• 2002

This study was done to investigate the effects of Korean mistletoe water extract and lectin on the apoptosis and preneoplastic lesion in chemically induced rat hepatocarcinogenesis. To attain the above objectives, weanling Sprague-Dawley male rats were fed modified AIN-76 diets containing 10% corn oil for 9 weeks. One week after feeding starts, rats were intraperitoneally injected twice with a dose of diethylnitrosamine (DEN, 50 mg/kg body weight (BW). Rats were provided with 0.05% phenobarbital (PB) in drinking water from one week after DEN treatment until the end of experiment. During the period of PB treatment, rats were injected with mistletoe extract (100 $\mu\textrm{g}$/kg BW) and lectin (10 $\mu\textrm{g}$/kg BW) twice a week. At the end of 9th week, rats were sacrificed and the formation of hepatic glutathione S-transferase placental form positive (GST-P$^{+}$) foci, apoptosis, DNA fragmentation and apoptosis related proteins were determined respectively. The formation of GST-P$^{+}$foci was significantly decreased by mistletoe extract or lectin treatment. Although there was no effect on apoptosis and DNA fragmentation in hepatic tissue by mistletoe extract or lectin treatment, caspase-9 and fas-L were increased. These results suggest that Korean mistletoe extract and lectin have a potential to inhibit hepatocarcinogenesis by increasing apoptosis.sis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.697-702
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• 2001

This study was done to investigate effects of Korean mistletoe extract and lectin on serum GOT, GPT and $\alpha$-L-fucosidase activities and the preneoplastic lesion in chemically induced rat hepatocarcinogenesis. To attain the above objectives weanling Sprangue-Dawley male rats were fed modified AIN-76 diets containing 10% corn oil for 9 weeks. One week after feeding rats were intraperitonealy injected twice with a dose of diethylnitrosamine (DEN, 50 mg/kg body weight(BW)) and were provided 0.05% phenobarbita (PB) with drinking water from one week after DEN treatment until the end of experiment. For the same period as PB treatment, rats were injected mistletoe extract (10 $\mu\textrm{g}$/kg BW European mistletoe, 10 $\mu\textrm{g}$/kg BW and 100 $\mu\textrm{g}$/kg BW Korean mistletoe) and lectin(1 ng/kg BW, 10 ng/kg BW) twice a week. At the end of 9th week rats were sacrificed and the formation of hepatic glutthione S-transferase placental form positive (GST-P+) foci serum GOT, GPT and $\alpha$-L-fucosidase activities were determined. By treatment of mistletoe extract or lectin there were no significant effects on serum GOP, GPT and $\alpha$-L-fucosidase activities whereas those activities showed a tendency to increase by DEN treatment. The formation of GST-P+ foci was significantly decreased by mistletoe extract or lectin treatment especially in group of 100$\mu\textrm{g}$/kg BW Korean mistletoe. These results suggest that Korean mistletoe extract and lectin have a possibility to inhibit hepatocarcinogenesis of animals.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1328-1336
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• 2003

This study was done to investigate the effects of n-3, n-6 fatty acid and d-limonene on the hepatic membrane lipid composition, protein kinase C (PKC) and glutathione S-transferase (GST) activities in experimental rat hepatocarcinogenesis. Sprague-Dawley female rats were fed with two different types of dietary oil for 20 weeks. Corn oil (CO) and sardine oil (SO) were used at 15% by weight as a source of n-6 and n-3 fatty acid, respectively. One week after feeding, rats were intraperitoneally injected twice with a dose of diethylnitrosamine (DEN, 50 mg/kg body weight) and after 1 week 0.05% phenobarbital (PB) was provided with drinking water. Membrane fractional lipid composition showed that the content of cholesterol was higher in 50 group than CO group and also significantly decreased by d-limonene. The content of phospholipid was increased by carcinogen treatment but not affected by dietary oils or d-limonene. Membrane C/PL molar ratio was significantly decreased by d-limonene or carcinogen treatment in 50 groups but not in CO groups. Fatty acid composition was changed by dietary oils but not by carcinogen treatment or d-limonene. Cytosolic PKC activity was not significantly different by dietary oils, d-limonene or carcinogen treatment. However, membrane PKC activity was significantly increased by carcinogen treatment and decreased by d-limonene. Cytosolic GST activity was affected by d-limonene or carcinogen treatment in all dietary groups. These data indicate that dietary oils, d-limonene and carcinogen treatment can not change much membrane phospholipid composition. But membrane C/PL molar ratio was changed by carcinogen treatment and d -limonene although the effect was different between dietary oils. Therefore, it is suggested that different dietary oils and d-limonene can somewhat modulate the changes of membrane fluidity and activities of membrane bound enzymes like membrane associated PKC during carcinogenesis.