• Journal of Environmental Health Sciences
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• v.32 no.1 s.88
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• pp.60-66
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• 2006

Bisphenol A(BPA) was known as an endocrine disrupting chemical. This study was conducted to assess the effect of BPA, weaker estrogen, on the preneoplastic and neoplastic lesions induced by diethylnitrosamine (DEN). One hundred male F344 rats were divided into four groups which were treated with DEN followed by BPA. To make liver tumor early, we conducted that DEN containing osmotic pump implanted into rat abdominal cavity. Then diet containing BPA were fed to the rats. All animals were sacrificed at 10 and 18 weeks. Body weights were significantly decreased in 4000ppm at 18 weeks. Relative Liver weights of 4000 ppm BPA treated group were significantly increased compared to that of DEN alone group at 18 weeks. There were no significant differences of liver tumor incidences. Sum area of GST-P positive foci and BrdU labeling indices of BPA treated group were not significantly different compared to those of control group. These results suggest that BPA have no effects in preneoplastic and neoplastic lesions on DEN-induced hepatocarcinogenesis.

• 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.

• Toxicological Research
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• v.5 no.2
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• pp.135-149
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• 1989

The effect of Ganoderma lucidum (Polyporaceae) extract on initiation and promotion of liver preneoplastic lesions in chemical carcinogenesis were examined in male rats. Male Fisher 344 rats, 8 weeks old, were injected i.p. with diethylnitro-samine(DENA` 200 mg/kg) as an initiator and were fed on diet containing 0.02%-acetaminofluorene (2-AAF) as a promoter for 2 weeks (group 1, 2` 2-4 week) and were fed on basal diet (group 3 and 4). The rats in test groups(group 1 and 3) were fed on diet containing 0.1% of Ganoderma lucidum extract for 6 weeks (2-8 week).

• Toxicological Research
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• v.27 no.4
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• pp.247-251
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• 2011

To clarify whether inhibitory effect of estrogen on liver tumor is associated with cell proliferation, we investigated its role in diethylnitrosamine (DEN)-induced rat preneoplastic lesions, with time sequenced manners. F344 male rats (n = 90) were divided into three groups at 5 weeks of age. The mini-osmotic pumps providing a continuous infusion of DEN was implanted into the abdominal cavity of each animal in group 1, 2 and 3 at 6 weeks of age. To see the effect of estrogen, pellet containing 1 or 10 ${\mu}g$ of estradiol-3-benzoate (EB) was implanted subcutaneously in the animals of groups 2 or 3, respectively, one week prior to DEN treatment. Ten animals of each group were euthanized at 10, 14 and 18 weeks after DEN treatment. Liver tissues at each time point were fixed in 10% phosphate-buffered formalin and were processed and embedded in paraffin and 5 ${\mu}g$ sections mounted on a silanized slide. Glutathione S-transferase placental form (GST-P) positive foci and 5-bromo-2-deoxyuridine (BrdU) labeling cells were detected at each time point. Area of GST-P positive foci in DEN+EB 1 or 10 ${\mu}g$ group was significantly decreased compared to DEN alone at 14 weeks (p < 0.01 or p < 0.05, respectively) an at 18 weeks (p < 0.05 or p < 0.01, respectively). BrdU index in DEN+EB 1 or 10 ${\mu}g$ groups was significantly decreased compared to DEN alone at 14 weeks and at 18 weeks (p < 0.01). Taken together, we conclude that EB treatment decrease the DEN-induced liver preneoplastic lesions and this may be associated with decrease of cellular proliferation.

• Korean Journal of Veterinary Pathology
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• v.1 no.2
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• pp.107-118
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• 1997

The anticarcinogenic effects of allyl methyl trisulfide(AMT) and methyl propyl disulfide(MPD) were studied in a 28 weeks rat multi-organ carcinogenesis model. Tumor incidence rate was decreased by AMT or MPD treatment comparing with the positive control. AMT treatment significantly decreased the incidence of neoplastic and preneoplastic lesions in the kidney thyroid gland urinary bladder alimentary tract lung and Zymbal's gland. MPD also inhibited incidence of noplastic and preneoplastic lesions in the liver kidney urinary bladder alimentary tract lung and Zymbal's gland but increased that in the thyroid gland. GST-p positive foci in the liver were slightly decreased by AMT or MPD. There was no significant histopathological lesions in AMT or MPD treated group without pretreatment of carcinogens.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.98-112
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• 2020

There is a strong connection between the diet rich in antioxidants and the decreased incidence of inflammatory bowel disease and cancerous diseases. Diets that are rich in anti-oxidants particularly include fruits and vegetables containing the high amounts of vitamin A-E, carotenoids, and minerals. The supercritical heat-treated radish extracts of the research result had an inhibitory effect on the development of aberrant crypt foci (ACF), namely, preneoplastic lesions having a potential to become cancer cells and reduced the number of the aberrant crypt foci (ACF) consisting of four or more aberrant crypts (AC) having high risk to become tumors by about half. The supercritical heat-treated radish extracts can reduce the incidence of preneoplastic lesions having a high risk of developing cancer by about 28 %. DSS-treated mice developed symptoms similar to those of human UC, such as severe bloody diarrhea and weight loss. Supercritical heat-treated radish extracts, as well as sulfasalazine, suppressed colonic length and mucosal inflammatory infiltration. In addition, supercritical heat-treated radish extracts treatment significantly reduced the expression of pro-inflammatory signaling molecules through suppression both mitogen-activated protein kinases (MAPK) and nuclear factor-kappa B (NF-kB) signaling pathways, and prevented the apoptosis of colon. Moreover, supercritical heat-treated radish extracts administration significantly led to the up-regulation of anti-oxidant enzyme including SOD and Catalase.

• Korean Journal of Bronchoesophagology
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• v.15 no.2
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• pp.30-35
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• 2009

Lung cancer could be developed through a series of morphological changes from dysplasia to carcinoma in situ and then invasive cancer. However, precancerous lesions are generally a few cell layers thick and are detected only by chance. Autofluorescence bronchoscopy(AFB) is one of the newly developed diagnostic tools to detect the pre-cancerous lesions m the bronchial tissue. Several studies have shown that AFB improved the rate of detection of cancer and dysplastic lesions of the airway, especially those in intraepithelial stage. However, there were high rates of false positive with AFB, and it is also important to develop non-biopsy methods because of lack of accurate information of variable course of preneoplastic lesions regarding progression. So, many other technologies were developed, such as narrow band imaging(NBI), endobronchoscopic ultrasound, optical coherence tomography, and confocal fluorescence microendoscopy. Among the new machines, NBI is a new optical technology that can clearly visualize the microvascular structure m the mucosal layer. NBI seems to increase specificity without compromising sensitivity. In the future such techniques would make it possible to precisely study in detail the natural history of the premalignant epithelium.

• Korean Journal of Veterinary Research
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• v.36 no.2
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• pp.417-428
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• 1996

In order to know the toxic effect and carcinogenic activity in rats and mice fed with juice of Korean native Petasites japonicus Maxim of its pellet(4% or 8%) which were dried, milled and mixed with basal diet, the investigations were carried out by macroscopy and histopathology. Macroscopically, although remarkable changes were not observed in the liver of mice, there were slight to moderate swelling of rat livers in the whole groups at 12 to 14 weeks after feeding and milky spots in rats fed with its juice and 8% pelleted Petasites japonicus Maxim diet and a normal diet for 1 week alternatively for 14 weeks. Moreover, moderate to severe swelling and milk spots were recognized in livers of all rats fed with its juice and 8% pellet or 8% pelleted Petasites japonicus Maxim for 16 weeks. But, in cases of rats fed with its juice and 4% pellet or 4% pelleted Petasites japonicus Maxim, only swelling of livers was recognized moderately or severely. Histopathologically, major lesions were found in livers of both rats and mice. There were congestion, hemorrhage, fatty change, focal necrosis, megalocytosis and hyperplasia of endothelial cell in livers of mice and rats, the additional lesions such as proliferation of bile duct and nodular regeneration with diffuse regenerating cells were seen in livers of rats. In addition, preneoplastic lesions, the areas of milky spots macroscopically, were observed in livers of rats fed with Petasites japonicus Maxim for 14 to 16 weeks. In a few cases, haemangioendothelial sarcoma in livers was detected in rats fed with Petasites japonicus Maxim for 16 weeks. Petasites japonicus maxim growing naturally in Korea seem to exhibit toxic effect especially in liver and it contained a causative agent of primary liver tumors.

• YAKHAK HOEJI
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• v.36 no.2
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• pp.180-187
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• 1992

This study investigated the hypothesis that carcinogen-induced elevation of oxyradical during the hepatocarcinogenesis in rat. The hepatic preneoplastic lesions in the Spraque-Dawley rats were induced by the carcinogen treatment such as diethylnitrosamine(DEN) and acetylaminofluorene(AAF) in combination with partial hepatectomy(PH). The liver sample was taken at 2, 6, 10 and 16 months after carcinogen treatments followed by PH. Carcinogen treatments initially increased the indices of oxidative damage(activities of xanthine oxidase and production rates of superoxide anion, microsomal hydrogen peroxide, hydroxyl radical) in the liver compared to PH groups. However, cytosolic hydrogen peroxide did not change significantly throughout the full time period. Of hydrogen peroxide scavenger, the catalase was remained lower than PH groups, whereas the peroxidase was increased after carcinogen treatments. Morphologically, the immunohistochemical analysis with glutathione-S-transferase of a placenta form(GSTP) antibody was used to detect the induction of preneoplastic nodules. During the hepatocarcinogenesis, both production rate of hydroxyl radical and activity of glutathione-S-transferase(GST) markedly increased with the appearance of the preneoplastic nodule. These results indicated that the hydroxyl radical of reactive oxygen species seemed to have a major influence on the hepatocarcinogenesis and the effect of time after removal of the carcinogen also appeared to be highly critical in the hepatocarcinogenesis.

• Journal of Microbiology
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• v.38 no.3
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• pp.169-175
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• 2000

Epidemiological and experimental studies provide evidences that diet and intestinal microflora play an important role in colon carcinogenesis. In recent years, it has been suggested that lactic acid bacteria (LAB) used to ferment dairy products have an inhibitory effect on the colon cancer. This study was designed to determine the effect of Bifidobacterium longum HY8001 (Bif) and Lactobacillus acidophilus HY2104(Lac) of Korean origin on azoxymethane (AOM)-induced colonic preneoplastic lesions such as aberrant crypt foci(ACF) formation and cecal pH. At five weeks of age, Spraque-Dawley rats were divided at random into four (AOM alone, Bif, ,Lac, and Bif+Lac) groups. Animals were weighed weekly and oral administration of LAB cultures were performed daily until the termination of the study. Two weeks later, all animals were given a subcutaneous injection of AOM dissolved in normal saline at a dose of 15 mg/kg of body weight once per week for 2 weeks. All rats were necropsied 7 weeks after the last AOM injection , and the ACF were visualize under light microscopy in the formalin-fixed, unsectioned methylene blue-stained colons. The total number of aberrant crypt in Bif, Lac, and Bif+Lac groups were significantly lower than that of the AOM alone group and the percentage of inhibitions weas 35.0, 45.6%, respectively. Significant inhibition (p<0.001) in the total number of ACF was also observed in LAB treated groups (Bif , Lac, and Bif+Lac group by 3003, 38.6, and 41.2%, respectively). Furthermore, cecal pH appeared to significantly decrease by LAB administration. The results of present study provide some evidences for potential colon tumor-inhibitory properties of lactic cultures and fermented dairy products.