Biomedical subjects

T Tsujiuchi

Publications and source records attributed to T Tsujiuchi.

At least 73 records · Page 4Linked to original sources

PubMed1996

Frequent mutations of Ki-ras but no mutations of Ha-ras and p53 in lung lesions induced by N-nitrosobis(2-hydroxypropyl)amine in rats.

Point mutations of the Ki-ras and p53 genes in rat lung lesions induced by N-nitrosobis(2-hydroxypropyl)amine (BHP) were investigated by polymerase chain reaction-single strand conformation polymorphism analysis followed by direct sequencing using paraffin-embedded tissues. Male Wistar rats 6 wk old were given 2000 ppm BHP in drinking water for 15 wk. Another group was given drinking water without BHP. The rats were killed 20-27 wk after the beginning of the experiment. Lung adenomatous and squamous lesions, including carcinomas, were induced. The frequencies of Ki-ras mutations were 40% (six of 15) in alveolar hyperplasias, 36% (five of 14) in adenomas, 72% (18 of 25) in adenocarcinomas, 20% (three of 15) in squamous metaplasias, 50% (three of six) in squamous cell carcinomas, and 50% (five of 10) in adenosquamous carcinomas. The mutations were all G-->A transitions at the second position of codon 12; no other mutations were detected. However, Ha-ras mutations in exons 1 and 2 and p53 mutations in exons 5, 6, and 7 were not detected in adenocarcinomas and squamous cell carcinomas. These results indicate that Ki-ras mutation is an early genetic event in some adenomatous and squamous lung carcinogeneses and that Ki-ras mutations can cause benign lesions to convert to malignant lesions. The results also show that Ha-ras and p53 mutations are not involved in rat lung carcinogenesis induced by BHP.

Adenocarcinoma↗

PubMed1996

Inhibitory effects of N,N'-diphenyl-p-phenylenediamine on the early stage of the enhanced hepatocarcinogenesis caused by coadministration of ethionine and a choline-deficient L-amino acid-defined diet in rats.

Effects of N,N'-diphenyl-p-phenylenediamine (DPPD), an antioxidant, on liver carcinogenesis caused by a choline-deficient L-amino acid-defined (CDAA) diet containing ethionine were studied in Fischer 344 rats. Male animals, 6 weeks old, were fed a CDAA diet, a choline-supplemented L-amino acid-defined (CSAA) diet or a CDAA diet containing 0.05% ethionine with or without 0.2% DPPD. Histological changes and lesions positive for gamma-glutamyltransferase (GGT) were analyzed 12 weeks after the beginning of the experiment. The levels of 8-hydroxyguanine (8-OHGua) in DNA and 2-thiobarbituric acid-reacting substances (TBARS) were measured as the parameters for cellular oxidative damage after 4 and 11 days of treatment. Expression of c-myc and c-Ha-ras was also investigated in relation to cell proliferation after 2, 4, 8 and 11 days. Histologically, development of diffuse fatty liver observed in rats fed a CDAA diet was inhibited, while massive oval cell proliferation and cholangiofibrosis resulted from the addition of ethionine with/without DPPD. The sizes but not numbers of GGT-positive lesions seen in the liver of rats fed a CDAA diet were increased and the levels of 8-OHGua formation and TBARS generation were also increased by the ethionine supplement. Both numbers and sizes of GGT-positive lesions were decreased and the level of TBARS, but not 8-OHGua, was decreased by adding DPPD. The increased expression of c-myc and c-Ha-ras detected in the liver of rats fed a CDAA diet was further increased by addition of ethionine and again reduced by DPPD. These results indicate that an antioxidant DPPD can inhibit the early stage of enhanced hepatocarcinogenesis caused by coadministration of ethionine and a CDAA diet, by blocking cellular oxidative damage as well as c-myc and c-Ha-ras expression.

Amino Acids↗

PubMed1996

Inhibition by acetylsalicylic acid, a cyclo-oxygenase inhibitor, and p-bromophenacylbromide, a phospholipase A2 inhibitor, of both cirrhosis and enzyme-altered nodules caused by a choline-deficient, L-amino acid-defined diet in rats.

Effects of inhibitors of arachidonic acid (AA) metabolism on the development of fatty liver, cirrhosis, glutathione-S-transferase placental form (GST-P)-positive nodules and the generation of 8-hydroxydeoxyguanosine (8-OHdG) and thiobarbituric acid-reactive substances (TBARS), caused by a choline-deficient, L-amino acid-defined (CDAA) diet, were examined in male Fischer 344 rats by feeding CDAA diets supplemented with the inhibitors for 12 and 30 weeks. Acetylsalicylic acid (ASA) (at doses of 0.1 and 0.2%) and p-bromophenacylbromide (BPB) (0.1 and 0.2%) were used as inhibitors of, respectively, cyclo-oxygenase and phospholipase A2, and quercetin (QU) (0.75 and 1.5%) and nordihydroguaiaretic acid (NDGA) (0.1 and 0.2%) as inhibitors of lipoxygenase. None of the inhibitors affected the development of fatty liver caused by the CDAA diet. ASA at a doe of 0.2% almost completely prevented the appearance of cirrhosis, GST-P-positive nodules, 8-OHdG and TBARS in seven out of 11 (63.7%) rats. BPB at a dose of 0.2% also exerted inhibitory effects on all of these lesions but to a lesser extent than ASA. QU and NDGA exerted inhibitory effects limited to the GST-P-positive nodule case. The results indicate that a perturbed AA metabolism, particularly of the cyclo-oxygenase pathway, derived secondarily from depletion of labile methyl groups or phosphatidylcholine, might play key roles in the cirrhosis, hepatocarcinogenesis and oxidative stress caused by a CDAA diet. The results also indicated a possible involvement of the lipoxygenase pathway in hepatocarcinogenic processes.

Acetophenones↗

PubMed1996

Disturbance of the cell cycle with colchicine enhances the growth advantage of diethylnitrosamine-initiated hepatocytes in rats.

The effect of cell cycle disturbance due to colchicine on the induction of enzyme-altered foci during liver regeneration in rats was studied. For initiation, diethylnitrosamine (DEN) at a dose of 10 mg/kg was injected intraperitoneally and partial hepatectomy (PH) was performed 4 h thereafter. Colchicine at doses of 0, 0.1, 0.25 and 0.5 mg/kg was injected intraperitoneally 1 and 3 days after the initiation, followed by application of selection pressure consisting of 2-acetylaminofluorene (AAF) and carbon tetrachloride (CCl4) administration. As end point lesions, gamma-glutamyltransferase (GGT)-positive enzyme-altered foci were assayed at week 5. There was no significant effect of colchicine on numbers of foci. However, a significant, dose-dependent increase in the area of GGT-positive lesions in the groups treated with colchicine was observed. Bromodeoxyuridine labeling indices were higher in foci induced in colchicine-treated rats than in the untreated rats. In a separate experiment, serum glutamic pyruvic transaminase was not increased significantly after DEN and colchicine treatment, and the mitotic index at 6 days after PH was increased in the liver of colchicine-treated rats. These results suggest that the cell cycle disturbance induced by colchicine causes more pronounced selective growth of cells initiated by DEN and colchicine, and this experimental model may be useful for analyzing the mechanisms underlying that growth advantage and the effects of cell cycle abnormalities in liver carcinogenesis.

Animals↗

PubMed1996

Shortened telomere length in hepatocellular carcinomas and corresponding background liver tissues of patients infected with hepatitis virus.

The telomere length in 20 surgically resected human hepatocellular carcinomas (HCCs) and adjacent non-cancerous livers with hepatitis virus infection were investigated. All the HCC samples examined demonstrated shorter telomere length than the corresponding non-cancerous liver tissues, the respective average values being 5.4 kbp and 8.8 kbp (P < 0.001). The shortening of telomere length was most prominent in HCCs larger than 30 mm in diameter, and in both tumors and non-cancerous livers it was more marked with hepatitis B virus as compared with hepatitis C virus infection. These results indicate that telomere shortening is associated with not only progression, but also development of HCC, and there is a possible difference in the nature of the association in patients with hepatitis viruses of B and C types.

Adult↗

PubMed1996

Increased telomerase activity in hyperplastic nodules and hepatocellular carcinomas induced by a choline-deficient L-amino acid-defined diet in rats.

Activation of telomerase has been reported in several human cancers, including hepatocellular carcinomas (HCCs). We investigated telomerase activity during hepatocarcinogenesis induced by a choline-deficient L-amino acid-defined (CDAA) diet in rats. Male F344 rats were given a CDAA diet or a choline-supplemented L-amino acid-defined (CSAA) diet from 6 weeks of age for 75 weeks, and subgroups were killed 10 weeks, 50 weeks and 75 weeks after the beginning of the experiment. Hyperplastic nodules and HCCs were noted in rats fed a CDAA diet for 50 weeks and 75 weeks, respectively. Normal control liver specimens were obtained from 6-week-old rats. Telomerase activity was assessed by using a telomeric repeat amplification protocol (TRAP). Normal liver and background parenchyma of rats fed either of the diets for 10 weeks or 50 weeks showed weak telomerase activity. In contrast, markedly increased levels were demonstrated in hyperplastic nodules and HCCs. These results suggest that increased telomerase activity may be a biological feature of preneoplastic lesions that evolve to HCCs in rat liver.

Amino Acids↗

PubMed1995

Inhibitory effects of sulfation inhibitors on initiation of pancreatic ductal carcinogenesis by N-nitrosobis(2-oxopropyl)amine in hamsters.

The effects of dehydroepiandrosterone sulfate (DHAS), a typical hydroxysteroid sulfotransferase (HSTase) inhibitor, and of 3'-phosphoadenosine 5'-phosphate (PAP), a nonspecific sulfation inhibitor on N-nitrosobis(2-oxopropyl)-amine (BOP)-induced initiation were examined in a rapid production model for pancreatic carcinomas in hamsters in order to elucidate the involvement of sulfotransferase in the metabolic activation of beta-oxypropylnitrosamines. While neither low nor high doses of DHAS and PAP exerted any significant influence on the incidence of ductal lesions including carcinomas, the high dose of DHAS (350 mg/kg body wt) and a both low (90 mg/kg) and high (180 mg/kg) doses of PAP reduced the mean numbers of pancreatic ductal adenocarcinomas. The high dose of PAP also reduced the number of all ductal lesions combined. The results thus suggest that metabolic activation with STase is involved in BOP-induced pancreatic ductal carcinogenesis in hamsters, and support the hypothesis that BOP is metabolized to beta-hydroxyalkylnitrosamines followed by activation to proximate sulfuric acid esters by HSTase.

Animals↗

PubMed1995

Prevention by methionine of enhancement of hepatocarcinogenesis by coadministration of a choline-deficient L-amino acid-defined diet and ethionine in rats.

The effects of methionine on hepatocarcinogenesis induced by coadministration of a choline-deficient L-amino acid-defined (CDAA) diet and ethionine were examined. F344 male rats were divided into 4 experimental groups. Groups 1 and 2 received the CDAA diet and a choline-supplemented L-amino acid-defined (CSAA)++ diet, respectively. Group 3 received the CDAA diet containing 0.05% ethionine, and group 4 the CDAA diet containing 0.05% ethionine and 0.47% methionine. Animals were killed after 12 weeks of treatment. Histologically, the CDAA diet induced intracellular fat accumulation and foci. In contrast, ethionine caused not only foci, but also hyperplastic nodules, cholangiofibrosis and the proliferation of oval cells without such fat accumulation. Methionine abolished the development of all of the liver lesions induced by coadministration of the CDAA diet and ethionine. To investigate the effects of methionine on induction of c-myc and c-Ha-ras expression, as well as generation of 8-hydroxyguanine (8-OHGua) and 2-thiobarbituric acid-reacting substances (TBARS), by coadministration of the CDAA diet and ethionine, subgroups of 3 to 5 animals were killed at 2, 4, 8, or 11 days after the beginning of the experiment. Coadministration of the CDAA diet and ethionine markedly enhanced the level of expression of c-myc and c-Ha-ras, 8-OHGua formation and TBARS generation as compared with the CDAA or CSAA diet within 11 days, and methionine blocks these actions. These results indicate that addition of methionine prevents the induction of c-myc and c-Ha-ras expression, 8-OHGua formation and TBARS generation, as well as hepatocellular lesions, by coadministration of the CDAA diet and ethionine in rats, and suggest a possible involvement of oxidative stress and gene expression in hepatocarcinogenesis by these agents.

Amino Acids↗

PubMed1995

ABO blood group genotype and plasma von Willebrand factor in normal individuals.

von Willebrand factor (vWF) is a multimeric plasma protein with ABO (H) blood group sugar chains. We investigated a total of 330 plasmas from normal individuals having various ABO genotypes, with special reference to vWF antigen and its platelet glycoprotein-Ib-related biological activities, termed ristocetin cofactor (RCof) and botrocetin cofactor (BCof). RCof reflects the biological activity of higher vWF multimers, while BCof reflects that of vWF of multimers of all sizes. Plasmas from normal individuals carrying one O gene (genotypes AO and BO) had slightly, but proportionally lower levels of vWF antigen, RCof, and BCof than those carrying no O gene (genotypes AA, AB, and BB). Normal plasmas from individuals carrying two O genes (genotype OO) showed much lower values for these parameters than the other plasmas, as previously reported. However, multimeric analysis of plasma vWF antigen revealed no differences among the different genotypes.

ABO Blood-Group System↗

PubMed1994

Effects of novobiocin on the induction of gamma-glutamyltranspeptidase positive foci in the liver of rats treated with diethylnitrosamine.

Effects of novobiocin on the induction of gamma-glutamyltranspeptidase(GGT)-positive foci, an early lesion occurring during hepatocarcinogenesis, after diethylnitrosamine(DEN) initiation were investigated in Fischer 344 rats. Animals were given DEN at a dose of 20 mg/kg b. w. followed by novobiocin at doses of 50, 100 and 200 mg/kg b. w. The latter two doses, but not 50 mg/kg b. w., significantly inhibited the development of GGT-positive foci, providing evidence of the possible involvement of mono(ADP-ribosyl)ation in the initiation phase of hepatocarcinogenesis in rats.

ADP Ribose Transferases↗

PubMed1994

Inhibitory effects of 2-O-octadecylascorbic acid and other vitamin C and E derivatives on the induction of enzyme-altered putative preneoplastic lesions in the livers of rats fed a choline-deficient, L-amino acid-defined diet.

Effects of a lipophilic derivative of vitamin C, 2-O-octadecylascorbic acid (CV-3611), as well as its parent L-ascorbic acid (AscA), DL-alpha-tocopherol (alpha-T) and its hydrophilic derivative, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), on the number and size of gamma-glutamyltransferase (GGT)-positive putative preneoplastic lesions were examined and compared with their influences on 8-hydroxyguanine formation in DNA and 2-thiobarbituric acid-reacting substance generation in the livers of rats fed a choline-deficient, L-amino acid-defined (CDAA) diet for 12 weeks. A total of 90 male Fischer 344 rats, 6 weeks old, were divided into 18 groups each consisting of five rats. Group 1 received the CDAA diet alone; Groups 2, 3 and 4 received the CDAA diet containing respectively 0.01, 0.05 and 0.10% CV-3611; Groups 5-7, 8-10 and 11-13 similarly received the CDAA diet containing AscA, alpha-T and Trolox, respectively, at these same low, middle and high concentrations; Group 14 received a choline-supplemented, L-amino acid-defined (CSAA) diet alone; Groups 15-18 were given the CSAA diet containing CV-3611, AscA, alpha-T and Trolox, respectively, all at the 0.10% level. While all four vitamin derivatives exerted inhibitory effects on all four parameters, in each case dose-dependently, CV-3611 demonstrated the most pronounced effects. The present results indicated that lipophilic vitamin C derivatives may be particularly effective chemopreventive agents against CDAA diet-associated, oxidative stress-related hepatocarcinogenesis via its superior antioxidative properties.

Amino Acids↗

PubMed1994

Inhibition by catechol and di(2-ethylhexyl)phthalate of pancreatic carcinogenesis after initiation with N-nitrosobis(2-hydroxypropyl)amine in Syrian hamsters.

The effects of dietary administration of catechol (CC), paramethylcatechol (PMC) and di(2-ethylhexyl)phthalate (DEHP) were compared with that of butylated hydroxyanisole (BHA) in Syrian hamsters initiated with N-nitrosobis(2-hydroxypropyl)amine (BHP). Development of pancreatic atypical hyperplasias and adenocarcinomas in terms of combined multiplicity was significantly reduced by CC and DEHP. A similar slight but non-significant tendency was observed for BHA, while PMC was without effect. No statistically significant reduction of liver or gall bladder lesions was observed. The results thus suggest that both antioxidant and peroxisome proliferator categories of agents can inhibit pancreatic carcinogenesis in hamsters.

Animals↗

PubMed1994

Prevention by acetylsalicylic acid of liver cirrhosis and carcinogenesis as well as generations of 8-hydroxydeoxyguanosine and thiobarbituric acid-reactive substances caused by a choline-deficient, L-amino acid-defined diet in rats.

Effects of acetylsalicylic acid (ASA) (aspirin) on the pathogenesis of fatty liver, cirrhosis and hepatocarcinogenesis caused by a choline-deficient L-amino acid-defined (CDAA) diet were examined in male Fischer 344 rats fed a CDAA diet supplemented with 0, 0.1, 0.2, 0.4 or 0.8% ASA for 30 weeks. ASA at concentrations of > 0.2% prevented the development of both cirrhosis and preneoplastic and neoplastic nodules, but without any directly associated prevention of fatty changes. ASA also prevented hepatocyte proliferation and the generation of thiobarbituric acid-reactive substances and 8-hydroxydeoxyguanosine caused by feeding the CDAA diet, analyzed, respectively, after 1, 12 and 12 weeks. The results clearly indicate that the anti-inflammatory drug ASA, which is not a lipotropic factor, can prevent the pathogenesis of cirrhosis and hepatocarcinogenesis caused by a CDAA diet, which is possibly partly associated with the prevention of reactive oxygen species production.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed1994

Expression of cripto in human pancreatic tumors.

The expression of cripto gene product was examined immunohistochemically in 45 surgically resected pancreatic tumors, including 32 invasive ductal carcinomas, 4 intraductal papillary adenocarcinomas, 4 intraductal papillary adenomas, 2 mucinous cystadenomas, 2 islet cell tumors, and one solid and cystic tumor, and compared with that in 32 areas of accompanying chronic pancreatitis present in the cases of invasive ductal carcinomas and 5 non-tumorous areas of pancreas without pancreatitis. All pancreatic ductal tumors including adenomas and carcinomas showed positive staining with no difference in terms of staining intensity among intraductal tumors and invasive carcinomas with or without mucin hypersecretion. Islet cell tumors were positively stained but the solid and cystic tumor was negative. Duct epithelial cells and acinar cells were negative but islet cells were positive in the pancreas tissues without pancreatitis. Cells arranged in duct-like structures in areas of accompanying chronic pancreatitis were positively stained. The results suggest that cripto expression might be associated with a growth advantage of tumor cells and also with differentiation to form duct-like structures.

Biomarkers, Tumor↗

PubMed1994

High rates of Ki-ras point mutation in both intra- and extra-hepatic cholangiocarcinomas.

The presence of the Ki-ras gene mutations in 14 cases of intrahepatic cholangiocarcinoma (IHC) and nine cases of extrahepatic cholangiocarcinoma (EHC) were investigated by polymerase chain reaction-single strand conformation polymorphism analysis. To obtain enriched tumor cell DNA, the microdissection method was used on formalin-fixed paraffin-embedded tissue sections. Point mutations at codon 12 of the Ki-ras gene were detected in seven (50%) of the 14 cases of IHC and six (67%) of the nine EHC cases. In all but one of the ras gene mutation cases, G to A transitions in the second position of codon 12 were detected, the exception being a G to T transition in the same position in one IHC. No point mutations were detected at codon 13 or 61 in either IHC or EHC. Furthermore, there was no demonstrable correlation between Ki-ras mutation and patient age, tumor Stage, histological findings or prognosis. The present results demonstrated a higher participation of Ki-ras gene mutations in EHC than found in previous studies, and provided a confirmation and extension of the results earlier reported by Tada et al. and Tsuda et al. for IHC.

Adult↗

PubMed1993

Increased expression of nucleoside diphosphate kinase/nm23 and c-Ha-ras mRNA is associated with spontaneous lung metastasis in rat-transplantable osteosarcomas.

The relationship between expression of nucleoside diphosphate kinase (NDP kinase)/nm23, c-Ha-ras, and c-myc genes and metastatic potential was assessed in rat-transplantable osteosarcoma lines, derived from spontaneous and chemical carcinogen (4-hydroxyamino quinoline 1-oxide)-induced osteosarcomas in Fischer 344/NS1c rats. These osteosarcomas possess metastatic potential and highly metastatic lines spontaneous osteosarcoma-selected lung metastatic lesions and 4-hydroxyamino-quinoline 1-oxide-induced osteosarcoma-selected lung metastatic lesions were respectively established by selectively transplanting lung metastatic lesions. Northern blot analysis revealed that the levels of NDP kinase/nm23 and c-Ha-ras gene expression were increased in line with metastatic ability; thus transcript levels were remarkably greater in both spontaneous osteosarcoma-selected lung metastatic lesions and 4-hydroxyamino-quinoline 1-oxide-induced osteosarcoma-selected lung metastatic lesions highly metastatic lines than in their respective low metastatic spontaneous and chemical carcinogen (4-hydroxyamino quinoline 1-oxide)-induced osteosarcoma counterparts. c-myc mRNA expression was observed in all tumor lines, without any correlation with metastatic ability. Southern blot analysis did not show evidence of gross rearrangement or amplification of NDP kinase/nm23, c-Ha-ras, or c-myc genes suggesting regulation of their gene expression at the transcriptional and/or posttranscriptional level. These results indicate that NDP kinase/nm23 and c-Ha-ras might be cooperatively involved in a positive manner in signal transduction processes, especially involving G-protein reactions, responsible for metastasis of rat-transplantable osteosarcomas.

Animals↗

PubMed1993

Correlation between lack of bone Gla protein mRNA expression in rat transplantable osteosarcomas and expression of both c-fos and c-jun proto-oncogenes.

Alkaline phosphatase (AP) activity and expression of bone Gla protein (BGP), c-fos, and c-jun were compared in two transplantable osteosarcomas with high potentials for metastasis to the lung. The original spontaneous osteosarcoma (SOS) gradually became histologically undifferentiated, losing its osteogenic activity during serial transfer, whereas the chemical (4-hydroxyaminoquinoline 1-oxide)-induced osteosarcoma (COS) retained osteogenesis. The two osteosarcomas showed similar doubling times and levels of lung metastasis, and strong AP activity was detected on the cell membranes of both. Northern blot analysis revealed that lack of BGP mRNA expression was associated with expression of both c-fos and c-jun proto-oncogenes in SOS. In contrast, neither c-fos nor c-jun mRNAs were detected but BGP mRNA was expressed in the case of COS. These results suggest that the c-fos and c-jun genes may suppress the expression of BGP mRNA relevant to differentiation and osteoid formation in rat osteosarcomas. However, this does not appear to be directly related to proliferative or metastatic biological behavior.

Alkaline Phosphatase↗

PubMed1993

Effects of oxidative stress induced by redox-enzyme modulation on the progression stage of rat hepatocarcinogenesis.

Effects of oxidative stress induced by redox-enzyme modulation on the progression stage of hepatocarcinogenesis were examined by monitoring both hepatocyte injury and hepatocellular carcinoma development in F344 rats bearing preneoplastic liver nodules induced by the Cayama-Farber procedure. Redox-enzyme modulation, which included increased cytochrome P450 reductase activity induced by phenobarbital-Na (100 mg/kg, i.p. for 3 days), inhibition of DT-diaphorase by dicumarol (25 mg/kg, i.p.), depletion of glutathione by phorone (200 mg/kg, i.p.), supplementation with the Fe(III) sodium salt of EDTA (50 mg/kg, i.p.) and redox-cycling activation by menadione (50 mg/kg, i.g.), exerted no prominent hepatocyte injury within nodules but did cause slight injury in the surrounding hepatocytes in nodule-bearing rats. The same treatments induced severe hepatocyte injury in non-treated normal rats. Redox-enzyme modulation performed every other week for 33 weeks significantly reduced the number of hepatocellular carcinomas developing in nodule-bearing rats. These results indicate that preneoplastic nodules are resistant to the oxidative stress induction caused by redox-enzyme modulation treatment and that, despite toxic effects in surrounding hepatocytes, no progression pressure is exerted. Indeed, the treatment rather demonstrates an inhibitory effect of the evolution of the nodules into hepatocellular carcinomas.

Alanine Transaminase↗