Biomedical subjects

Shoji Fukushima

Publications and source records attributed to Shoji Fukushima.

At least 19 recordsLinked to original sources

PubMed2006

Evaluation of the toxicity of mastic gum with 13 weeks dietary administration to F344 rats.

Dietary toxicity of mastic gum, a natural food additive, was studied in male and female F344 rats fed 0%, 0.22%, 0.67% and 2% levels mixed into powdered basal diet for 13 weeks. No mortality or obvious clinical signs were observed in any of the animals throughout the experimental period. Body weights were significantly reduced in the high dose-treated group from week 2 to the end of the experiment in males, and at weeks 8 and 13 in females. There were increased absolute and relative liver weights in a dose-related manner or limited to the high dose group males or females, along with changes in hematological parameters, including increased WBC and platelet in high dose males. Altered serum biochemistry parameters included increases of total proteins, albumin, and total cholesterol in both sexes, and gamma-GTP in females only. However, macroscopic examination at necropsy revealed no gross lesions, and microscopic examination also revealed no treatment-related findings in any organs examined. As dietary treatment of mastic gum for 13 weeks in the present study caused decreased body weights at the high dose, especially in males, and increased liver weights in a dose-related manner in both genders without any morphological findings, it is concluded that the administration of it has a no observed adverse effect level (NOAEL) of 0.67% in the diet.

Administration, Oral↗

PubMed2006

Upregulation of fibroblast growth factor receptor 3 and epidermal growth factor receptors, in association with Raf-1, in urothelial dysplasia and carcinoma in situ after the Chernobyl accident.

The present study was carried out in order to examine the molecular status of selected growth factor receptors (GFR) in urinary bladder lesions, recently described by our group as representing 'Chernobyl cystitis'. Fibroblast growth factor receptor 3 (FGFR3), epidermal growth factor receptor 1 (EGFR1), EGFR2neu (a member of the same family), p53 and Raf-1 serine/threonine kinase expression were evaluated immunohistochemically in urinary bladder biopsies from 22 men with benign prostate hyperplasia (group 1). For comparison, 16 men with benign prostate hyperplasia and five women with chronic cystitis living in non-radio-contaminated areas of the country were also investigated as controls (group 2). Additionally, 14 patients with dysplasia, carcinoma in situ (CIS) and primary urothelial carcinoma (UC) operated before the Chernobyl accident as well as 23 patients with UC living in the radio-contaminated areas were included as pre- and post-Chernobyl UC groups 1 and 2, respectively. Chronic proliferative atypical cystitis ('Chernobyl cystitis') was observed in group 1 patients. Foci of dysplasia and CIS were found in 22 (100%) and 19 (86%) of the 22 cases, respectively; moreover, two small UC were also detected. Elevated levels of FGFR3, EGFR2/neu, p53 and to a lesser extent EGFR1 and Raf-1 expression in the urothelial dysplasia and CIS were evident for patients of group 1. Statistically significant differences in immunohistochemical scores for FGFR3, EGFR1, p53 and Raf-1 were observed between groups 1 and 2 and between group 1 and the post-Chernobyl UC group 2, where a change in expression of EGFR2/neu was also noted. A significant decrease in FGFR3 expression in additional pre-Chernobyl UC group 1 with dysplasia, CIS and UC compared with group 1 Chernobyl cystitis cases was detected. Our findings suggest that FGFR and EGFR signaling pathways, associated with p53 and Raf-1 activation, may contribute to multistage urothelial carcinogenesis caused by irradiation, through autocrine or paracrine growth stimulation.

Adult↗

PubMed2006

High sensitivity of fatty liver Shionogi (FLS) mice to diethylnitrosamine hepatocarcinogenesis: comparison to C3H and C57 mice.

The fatty liver Shionogi (FLS) mouse is a new inbred strain that spontaneously develops fatty liver with infiltration of mononuclear cells. Moreover, this mouse is known to frequently develop spontaneous hepatic cancers. Recently, human non-alcholic steatohepatitis (NASH) has been focused of attention regarding hepatocellular carcinoma. Therefore, this mouse has potential as a model for human hepatic cancer due to steatosis. It is of interest therefore, whether it exhibits elevated susceptibility not only regarding spontaneous tumor development but also to chemical hepatocarcinogens. To examine this concern, we examined diethylnitrosamine (DEN) hepatocarcinogenesis in FLS mice with 30ppm in drinking water for 26 weeks in comparison to two other strains of mice, C3H and C57. The induction of spontaneous and DEN-induced hepatic tumors was clearly increased in the FLS case, along with levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, as compared to the other strains, with or without DEN treatment. These results indicate that the oxidative DNA stress is intimately involved in hepatocarcinogenesis in FLS mice and provide further support for use of this mouse as a useful model for investigating hepatocarcinogenesis due to human hepatic steatosis.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2006

Existence of no-observed effect levels for 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline on hepatic preneoplastic lesion development in BN rats.

There is increasing evidence that dose-response curve of genotoxic carcinogen is nonlinear and a practical threshold dose exists. However, little is known about differences in the dose-response relationship of genotoxic carcinogen among different strain rats. Herein, we showed that low doses of genotoxic carcinogen 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (MeIQx) had no effects on induction of liver glutathione S-transferase placental form (GST-P)-positive foci in both BN and F344 rats, and therefore demonstrated the existence of no-observed effect level for hepatocarcinogenicity of this genotoxic carcinogen irrespective of strains. These findings further support our notion that a practical threshold dose for MeIQx hepatocarcinogenicity exists in rats.

Animals↗

PubMed2006

Involvement of ubiquitination and sumoylation in bladder lesions induced by persistent long-term low dose ionizing radiation in humans.

PURPOSE: We determined whether ubiquitination and sumoylation processes are up-regulated in bladder urothelium by chronic, long-term, persistent low doses of ionizing radiation in male patients with benign prostate hyperplasia and females with chronic cystitis living more than 19 years in 137Cs contaminated areas after the Chernobyl accident in Ukraine. MATERIALS AND METHODS: Bladder urothelial biopsies from 45 patients were subjected to histopathological and immunohistochemical study of Ub, SUMO1, SUMO E2 conjugating enzyme Ubc9, and the cell cycle inhibitors p53 and p27(Kip1). RESULTS: Of 25 group 1 patients from radio contaminated areas chronic proliferative atypical cystitis (Chernobyl cystitis), featuring multiple foci of dysplasia, and carcinoma in situ were observed in 23 (92%) and 19 (76%), respectively, in addition to 1 small pTa grade 1 urothelial carcinoma. Chronic cystitis with areas of dysplasia and urothelial hyperplasia were detected in 2 (10%) and 3 (15%), respectively of the 20 patients in control group 2 from clean (without radio contamination) areas of Ukraine. Greatly increased levels of Ub, SUMO1, Ubc9 and p53 as well as decreased levels of p27(Kip1) were evident in patients in group 1 compared to those in group 2 (all p <0.001). CONCLUSIONS: These findings support the hypothesis that up-regulated ubiquitination and sumoylation processes might be an adaptive response to unscheduled proteolysis of aberrant p53 and p27(Kip1) cell cycle regulators occurring with long-term low dose rate ionizing radiation exposure with a possible contribution to urothelial carcinogenesis.

Aged↗

PubMed2006

Absence of beta-catenin alteration in hepatic tumors induced by p-nitroanisole in Crj:BDF1 mice.

In the present study, beta-catenin localization in hepatocellular neoplasms and hepatoblastomas, induced by oral administration of p-Nitroanisole (pNA) in Crj:BDF1 for 2 years, was evaluated by immunohistochemistry along with genetic alterations in exon 2 of beta-catenin by the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) approach. Genomic DNA was isolated from paraffin sections of a total of 53 liver tumors. Immunohistochemical analysis revealed no abnormal accumulation of the beta-catenin protein in any of the cases. No mutations (0/13), 20% silent mutations (3/15) and 8% silent plus 12% functional mutations (2 + 3/25), not in the multiple phosphorylation sites of beta-catenin, were observed in hepatocellular adenomas, carcinomas and hepatoblastomas, respectively. The results indicate that beta-catenin does not play an important role in development of hepatic tumors induced by pNA in Crj:BDF1 mice.

Animals↗

PubMed2006

Existence of no hepatocarcinogenic effect levels of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline with or without coadministration with ethanol.

There is increasing evidence of the existence of no effect levels for genotoxic carcinogens. However, only limited information is available regarding dose-response curves for combination effects of multiple carcinogens at low dose. In the present study, 280 male F344 rats were divided into 14 groups to determine the effects of co-administration of various doses of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 10% ethanol on the development of glutathione S-transferase placental form (GST-P)-positive foci in the liver. The results provided concrete evidence for the existence of no effect levels for hepatocarcinogenicity of MeIQx either in presence or absence of ethanol and, therefore, for a practical threshold for this genotoxic carcinogen.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2006

Aged garlic extract inhibits development of putative preneoplastic lesions in rat hepatocarcinogenesis.

A unique garlic preparation, aged garlic extract (AGE), was examined for its modifying effect on diethylnitrosamine (DEN)-induced neoplasia of the liver in male F344 rats, using the medium-term bioassay system based on the 2-step model of hepatocarcinogenesis. Carcinogenic potential was scored by comparing the numbers and areas of induced glutathione S-transferase placental form (GST-P)-positive hepatocellular foci. GST-P-positive foci were significantly decreased in rats treated with AGE at doses of 2, 5, and 10 mL/kg, i.g., 5 times per week during the promotion phase. In addition, to clarify the mechanism underlying the inhibitory effect of AGE, the effect of AGE on hepatocellular proliferation was evaluated using partially hepatectomized rats as a liver-regeneration model. The bromodeoxyuridine-labeling indices in the livers of the AGE group were significantly lower than those in the control group at 24 h, the maximum proliferation period after partial hepatectomy. These findings indicate that AGE inhibited the development of putative preneoplastic lesions in rat hepatocarcinogenesis, involving a slowing in the proliferation rate of liver cells after partial hepatectomy.

Animals↗

PubMed2006

Aberrant expression of E-cadherin and beta-catenin in association with transforming growth factor-beta1 in urinary bladder lesions in humans after the Chernobyl accident.

This study examines the molecular pathways of cell-cell communication in chronic inflammatory processes associated with long-term low-dose urinary bladder exposure to ionizing radiation in people without major disease living more than 19 years in radio-contaminated areas of Ukraine after the Chernobyl accident. Patterns of components of the E-cadherin/beta-catenin complex, and transforming growth factor-beta1 (TGF-beta1) and inducible nitric oxide synthase (iNOS) expression were immunohistochemically evaluated in urinary bladder biopsies from 52 males with benign prostate hyperplasia and 8 females with chronic cystitis (group 1). For comparison, 25 males and 6 females living in non-contaminated areas of Ukraine were also investigated (group 2). Fourteen patients with primary urothelial carcinomas, which were operated on before the Chernobyl accident, were included as a carcinoma group. Chronic proliferative atypical cystitis ('Chernobyl cystitis') was observed in group 1 patients. Foci of dysplasia and carcinoma in situ were found in 51 (85%) and 34 (57%) of the 60 cases, respectively. Chronic cystitis with areas of dysplasia was detected in only 4 (13%) cases of 31 group 2 patients. Statistically significant differences in immunohistochemical scores for TGF-beta1 in the urothelium and lamina propria, iNOS in the urothelium and both beta-catenin and E-cadherin in the cytoplasm were observed between groups 1 and 2 with marked expression in group 1. Furthermore, TGF-beta1 overexpression and alteration in E-cadherin/beta-catenin complexes in bladder urothelium might play a crucial role in urinary bladder carcinogenesis in humans exposed to long-term low-dose ionizing radiation.

Adult↗

PubMed2006

Existence of a no effect level for MeIQx hepatocarcinogenicity on a background of thioacetamide-induced liver damage in rats.

As exposure to heterocyclic amines might increase the risk of liver cancer, we investigated the carcinogenic potential of MeIQx under conditions of liver damage caused by TAA. Male, 6-week-old F344 rats (n = 280) were divided into 14 groups; groups 1-7 received TAA (0.03% in drinking water) and groups 8-14 received water for the first 12 weeks. Thereafter, the animals received MeIQx at doses from 0, 0.001, 0.01, 0.1, 1, 10 to 100 p.p.m. (groups 1-7 and 8-14, respectively) in pellet basal diet for 16 weeks. All survivors were killed at week 28 for assessment of numbers and areas of GST-P positive foci, considered to be pre-neoplastic lesions of the liver. Values were increased significantly in all the groups receiving TAA-->MeIQx compared to MeIQx alone (P < 0.01). Numbers of GST-P positive foci were significantly increased in groups 7 and 14 (treated with 100 p.p.m. MeIQx) as compared to 0 p.p.m.-MeIQx (groups 1 and 8) (P < 0.01), along with areas in group 14 compared to group 8 (P < 0.01). However, with the maximum likelihood method, the data for numbers of GST-P positive foci (groups 1-7 and groups 8-14) fitted the hockey stick regression model, representing no differences from groups 1-5 and from groups 8-13, despite a linear dose-dependent increase of MeIQx-DNA adducts from 0.1 to 100 p.p.m. We conclude that there is a no effect level for MeIQx hepatocarcinogenicity, even on a background of TAA-induced liver damage.

5-Methylcytosine↗

PubMed2006

Possible tumor development from double positive foci for TGF-alpha and GST-P observed in early stages on rat hepatocarcinogenesis.

Expression of TGF-alpha during promotion of neoplastic development from GST-P-positive foci in rat chemical hepatocarcinogenesis was investigated. One-hundred male F344 rats were given a single intraperitoneal injection of DEN (200 mg/kg bodyweight) and subjected to two-thirds partial hepatectomy at week 3. Commencing 2 weeks from the start, PB at doses of 0 or 500 p.p.m. was fed to the rats for 46 weeks. Groups of 10 rats were killed at weeks 4, 8, 16, 32, 48 and their livers were immunohistochemically examined for expression of GST-P and TGF-alpha. TGF-alpha-positive foci and single positive cells were observed from week 4, partially overlapping with GST-P-positive foci but being much fewer. Numbers of TGF-alpha-positive lesions did not increase from weeks 4-48, but their areas showed increment at weeks 32 and 48, especially with PB administration. Almost all of the tumors observed at weeks 16, 32 and 48 were positive for TGF-alpha (98%). In addition, epidermal growth factor receptor overexpression was observed in most TGF-alpha-positive lesions (foci and tumors). The proliferating cell nuclear antigen labeling index in double positive foci for GST-P and TGF-alpha was significantly higher than that in TGF-alpha-negative foci. In conclusion, TGF-alpha may be closely related with promotion from altered foci to neoplasms in rat hepatocarcinogenesis. Our data suggest that double positive foci for GST-P and TGF-alpha in the early stages of rat hepatocarcinogenesis may develop into tumors with promotion.

Animals↗

PubMed2006

[Development of invasive urinary bladder carcinomas].

In this paper, we report on invasive urinary bladder carcinomas as follows, (1) p53 mutations have an important role in promotion and progression stages of carcinogenesis, (2) invasive bladder carcinomas occur multi-centrically in the bladder, (3) an organic arsenic, dimethylarsinic acid exerts carcinogenicity in the bladder of rats, (4) p53 mutations in carcinomas are caused by different carcinogens, and (5) bladder urothelium of people living in 137Cs-contaminated areas of Ukraine showed chronic proliferative atypical cystitis (so-called Chernobyl cystitis).

Animals↗

PubMed2005

N-acetylcysteine and S-methylcysteine inhibit MeIQx rat hepatocarcinogenesis in the post-initiation stage.

N-acetylcysteine (NAC) and S-methylcysteine (SMC), water soluble organosulfur compounds contained in garlic, were evaluated for chemoprevention of hepatocarcinogenesis after 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) initiation in rats. Intergastric treatment with NAC or SMC five times a week resulted in decreased numbers and areas of preneoplastic, glutathione S-transferase placental form (GST-P) positive foci of the liver in a dose-dependent manner. Moreover, cell proliferation was reduced in GST-P positive foci by NAC and SMC. Insulin-like growth factor I (IGF-I) and inducible nitric oxide synthase (iNOS) mRNA expressions were found downregulated in the liver by NAC. The studies indicate that NAC can serve as a chemopreventive agent for rat hepatocarcinogenesis induced by MeIQx by reducing cell proliferation, which may involve IGF-I and iNOS downregulation.

Acetylcysteine↗

PubMed2005

Concordance of thresholds for carcinogenicity of N-nitrosodiethylamine.

Three publications on the carcinogenicity of N-nitrosodiethylamine (NDEA) in the livers of F-344 or Wistar rats were examined for concordance of the data. Two reports recorded the appearance of tumors after treatment with NDEA, although one used a different dosing schedule that included phenobarbital promotion. Two studied glutathione S-transferase-placental positive (GST-p+) foci in liver at several doses. One also analyzed DNA for adducts from NDEA. This analysis revealed that when the dose was calculated in molecules/kg/day, the thresholds for the incidence of liver tumors were different by about 1.5 orders of magnitude. But when the dose was calculated as the total cumulative dose, the thresholds for tumor appearance (about 10(20.3) molecules/kg) were in agreement within the error of calculation. Combining the data for GST-p+ foci revealed remarkable agreement between the two reports and a threshold for the appearance of these foci at about 10(19.5) molecules/kg of total cumulative dose of NDEA. DNA adducts fit an exponential curve better than a linear. GST-p+ foci and adducts from NDEA were observed at doses below the threshold dose for the appearance of tumors. These results suggest that: cumulative dose is a better metric than daily dose and that adducts and GST-p+ foci appear at doses below those at which tumors appear. These results further support the observations of the authors that thresholds for carcinogenicity of this genotoxic carcinogen exist and that adducts and altered foci appear at lower doses than the threshold for carcinogenicity.

Animals↗

PubMed2005

Testicular toxicity of DEHP, but not DEHA, is elevated under conditions of thioacetamide-induced liver damage.

As part of an investigation of possible enhancement by liver disease of testicular toxicity caused by phthalates, we tested the effects of di(2-ethylhexyl)phthalate (DEHP) and di(2-ethylhexyl)adipate (DEHA) in a thioacetamide (TAA)-induced rat liver damage model. Male, 6-week-old, F344 rats (n=60) were divided into ten groups. Animals of groups 1-5 received TAA (200 mg/kg, intraperitoneal, three times per week) for 4 weeks, and groups 6-10 served as controls without TAA. After a 1 week interval, at week 5, powder diet containing DEHP or DEHA was provided to the animals of groups 1 and 6 (DEHP 25000 ppm), groups 2 and 7 (DEHP 6000 ppm), groups 3 and 8 (DEHA 25000 ppm) and groups 4 and 9 (DEHA 6000 ppm), while groups 5 and 10 received basal diet. All animals were sacrificed at week 9. Significant decrease in sperm numbers and motility and increase in morphology abnormalities were evident in group 1 as compared to groups 5 and 6 (p<0.01). However, DEHA treatment was not associated with any apparent testicular toxicity in either TAA- or vehicle-treated animals. Histopathological examination of the testes revealed severe atrophy and degeneration of testicular tubules in all animals given TAA and DEHP at high dose, only mild to moderate lesions being found with DEHP alone. We conclude that liver toxicity induced by TAA is associated with the enhancement of testicular toxicity of DEHP, but not DEHA, in rats.

Adipates↗

PubMed2005

Role of Na+, K+-ATPase alpha1 subunit in the intracellular accumulation of cisplatin.

The present study was undertaken to identify what regulates intracellular cisplatin (CDDP) accumulation and what changes in membrane fraction of CDDDP-resistant cell line. The CDDP-resistant rat hepatoma cell line, H4-II-E/CDDP, shows a significant decrease in intracellular platinum accumulation compared with parental H4-II-E cells, although there was no difference in the efflux of CDDP between these two cell lines. In this study, we examined the contribution of functional change in active transport to the CDDP resistance of H4-II-E/CDDP cells. Compared with the resistant cells, platinum accumulation in the parental cells was clearly decreased by low temperature or ATP depletion. In addition, the Na+, K+-ATPase inhibitor ouabain and the K+ channel inhibitor tetraethylammonium decreased platinum accumulation in parental cells but did not change the accumulation in resistant cells. Amphotericin B, an antifungal agent, increased the intracellular platinum accumulation in resistant cells to the same level as in parent cells. Western blot analysis demonstrated that the Na+, K+-ATPase alpha1 subunit was reduced in resistant cells compared with the parental cells, although there was no difference in the expression of the beta1 subunit between the two cell lines. Furthermore, the Na+, K+-ATPase alpha1 subunit of H4-II-E was decreased following a 24-h exposure to CDDP. These results suggest that Na+, K+-ATPase-dependent active transport of CDDP does not occur in resistant cells, and, furthermore, our findings provide the first evidence that the Na+, K+-ATPase alpha1 subunit plays an important role in the transport of CDDP.

Animals↗

PubMed2005

Low dose DDT inhibition of hepatocarcinogenesis initiated by diethylnitrosamine in male rats: possible mechanisms.

Previously we reported a tendency for reduction of the development of glutathione-S-transferase placental form (GST-P) positive foci, recognized as preneoplastic changes in rat liver, by a low dose of 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane (DDT), which belongs to the same group of hepatic cytochrome P-450 inducers as phenobarbital and is itself a non-genotoxic hepatocarcinogen. In order to clarify the biological significance of this phenomenon, we investigated the reproducibility and changes in other parameters using an initiation-promotion model in which male F344 rats were treated with DDT at doses of 0, 0.005, 0.5, 500 ppm in the diet for 11 or 43 weeks after initiation of hepatocarcinogenesis with N-diethylnitrosamine (DEN). When 500 ppm DDT was applied, the formation of GST-P positive foci and tumor were markedly elevated. In contrast, induction of GST-P positive foci and liver tumors tended to be inhibited at a dose of 0.005 ppm, correlating with protein levels of cytochrome P450 2B1 and 3A2 (CYP2B1 and 3A2) and generation of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage. mRNA levels for 8-oxoguanine glycosylase 1 (OGG1), an 8-OHdG repair enzyme, connexin 32 (Cx32), a major component of Gap junctions, and hepatic nuclear factor 1alpha (HNF-1alpha), a Cx32 regulator, were inversely correlated with GST-P positive foci and tumor formation. These results indicate that low dose DDT may indeed exhibit inhibitory effects on chemically initiated-rat hepatocarcinogenicity, in contrast to the promotion observed with high doses, and that this is related to changes in metabolizing enzymes, cell communication, and DNA damage and its repair.

Administration, Oral↗

PubMed2005

Alpha-benzene hexachloride exerts hormesis in preneoplastic lesion formation of rat hepatocarcinogenesis with the possible role for hepatic detoxifying enzymes.

Recently there has been a shift in the prevailing paradigm regarding the dose dependence of carcinogen action with increasing acceptance of hormesis phenomenon, although underlying mechanisms remain to be established. To ascertain whether alpha-benzene hexachloride (alpha-BHC) might act by hormesis, rats were initiated with diethylnitrosamine and then alpha-BHC ranging from 0.01 to 500 ppm was administered in the diet for 10 weeks. The highest concentration of alpha-BHC significantly increased the number and area of glutathione S-transferase placental form (GST-P) positive foci, preneoplastic lesions in the liver, but its low dose, 0.05 ppm, caused significant reduction, showing a J-shape dose-response curve. The proliferating cell nuclear antigen positive index for GST-P positive foci in the low dose-treated group was significantly reduced. The dose response curves of CYP450 content, NADPH-P450 reductase activity and 8-hydroxydeoxyguanosine formation revealed the same pattern as GST-P positive foci data. The response curves of CYP2B1 and 3A2 in their activities, protein and mRNA expression showed a threshold but CYP2C11 activity exhibited an inverted J-shape. These results might suggest the possibility of hormesis of alpha-BHC at early stages of rat hepatocarcinogenesis. The possible mechanism involves induction of detoxifying enzymes at low dose, influencing free radical production and oxidative stress, and consequently pathological change in the liver.

8-Hydroxy-2'-Deoxyguanosine↗