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Biomedical subjects

Yukihiko Adachi

Publications and source records attributed to Yukihiko Adachi.

At least 19 recordsLinked to original sources
PubMed2006

Expression of large tenascin-C splice variants by hepatic stellate cells/myofibroblasts in chronic hepatitis C.

BACKGROUND/AIMS: Earlier studies have suggested involvement of tenascin-C (TN-C) in liver fibrosis. Here, we examined expression of TN-C variants and types of alternatively spliced fibronectin-type III (FNIII) repeats in chronic hepatitis. METHODS: Using three monoclonal antibodies against TN-C variants, immunohistochemical staining was performed and the correlation with histological parameters of chronic hepatitis C was examined. The cellular source was also determined and variant expression and their types were tested using isolated rat hepatic stellate cells (HSCs), liver myofibroblasts, and/or LI90 cells. RESULTS: Large variants were not expressed in normal liver, but were up-regulated in chronic hepatitis, especially at sites of interface hepatitis and confluent necrosis, showing stronger correlations between staining intensity and these than with other parameters or fibrosis. TN-C deposition was closely correlated with increase in the number of alpha-smooth muscle actin-positive cells, i.e. activated HSCs/myofibroblasts, and in situ hybridization showed TN-C mRNA signals in the cells. Activated HSCs and myofibroblasts in culture highly expressed large variants of TN-C. In LI90 cells, sequencing of large variants revealed that the FNIII repeats D and A1/A4, followed by B, were preferentially included. CONCLUSIONS: TN-C and its variants are produced by HSCs/myofibroblasts, suggesting important roles in liver fibrogenesis.

Actins↗
PubMed2006

Hepatic oxidative DNA damage correlates with iron overload in chronic hepatitis C patients.

Hepatic oxidative stress occurs in chronic hepatitis C (CH-C), but little is known about its producing mechanisms and precise role in the pathogenesis of the disease. To determine the relevance of hepatic oxidatively generated DNA damage in CH-C, 8-hydroxy-2'-deoxyguanosine (8-OHdG) adducts were quantified in liver biopsy specimens by immunohistochemical staining, and its relationship with clinical, biochemical, and histological parameters, and treatment response was assessed in 40 CH-C patients. Hepatic 8-OHdG counts were significantly correlated with serum transaminase levels (r=0.560, p=0.0005) and histological grading activity (p=0.0013). Remarkably, 8-OHdG levels were also significantly related to body and hepatic iron storage markers (vs serum ferritin, r=0.565, p=0.0004; vs hepatic total iron score, r=0.403, p=0.0119; vs hepatic hepcidin messenger RNA, r=0.516, p=0.0013). Baseline hepatic oxidative stress was more prominent in nonsustained virological responder (non-SVR) than in SVR to interferon (IFN)/ribavirin treatment (50.8 vs 32.7 cells/10(5) microm2, p=0.0086). After phlebotomy, hepatic 8-OHdG levels were significantly reduced from 53.4 to 21.1 cells/10(5) microm2 (p=0.0125) with concomitant reductions of serum transaminase and iron-related markers in CH-C patients. In conclusion, this study showed that hepatic oxidatively generated DNA damage frequently occurs and is strongly associated with increased iron deposition and hepatic inflammation in CH-C patients, suggesting that iron overload is an important mediator of hepatic oxidative stress and disease progression in chronic HCV infection.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2006

Lactoferrin inhibits lipid peroxidation in patients with chronic hepatitis C.

Lactoferrin is a milk protein with inhibitory effect on lipid peroxidation induced by oxidative stress. Oxidative stress plays an important role in the pathogenesis of chronic hepatitis C (CHC). The aim of this study was to evaluate the effect of bovine lactoferrin (bLF) monotherapy on lipid peroxidation, hepatic inflammation and iron metabolism in patients with CHC. Ninety Japanese patients with CHC were randomly assigned to two groups: bLF group (n=47) treated with bLF at a dose of 3.6g/day and a control group (n=43) that remained untreated. Plasma 8-isoprostane levels and clinical laboratory data including iron metabolism parameters were measured. Plasma 8-isoprostatne level was significantly decreased from 8.6+/-3.7 to 6.9+/-2.1pg/ml in the bLF group (P<0.05). Plasma levels of 8-isoprostane did not significantly change in the control group. The decline in plasma 8-isoprostane levels was positively correlated with improvement in the level of ALT in the bLF group. No significant change in serum HCV RNA levels or iron metabolism markers was found after bLF treatment. Therapy with bLF was associated with improvement in lipid peroxidation and ALT levels in CHC. Administration of bLF is a promising therapeutic approach for suppressing oxidative stress in non-responders to antiviral therapy.

Journal Article↗
PubMed2006

Increased oxidative stress is associated with decreased circulating levels of adiponectin in Japanese metabolically obese, normal-weight men with normal glucose tolerance.

To investigate the relationship between oxidative stress and circulating levels of adiponectin in Japanese metabolically obese, normal-weight [MONW; BMI<25 and visceral fat area; VFA > or =100 cm2 by abdominal computed tomography (CT) scanning] men with normal glucose tolerance (NGT), we measured the plasma levels of free 8-epi-prostaglandin F2alpha (8-epi-PGF2alpha) and adiponectin in 28 MONW and 23 normal men. The plasma levels of free 8-epi-PGF2alpha were measured using a commercially available enzyme immunoassay (EIA) kit (Cayman Chemical, Ann Arbor, MI). The plasma levels of adiponectin were measured using a radioimmunoassay kit (LINCO Research, St. Charles, MO). Plasma levels of 8-epi-PGF2alpha in MONW subjects (30.4+/-4.0 pg/ml; P<0.01) were significantly increased compared to controls (8.1+/-1.3 pg/ml). The plasma levels of adiponectin were significantly decreased in MONW subjects (8.6+/-0.9 microg/ml; P<0.01) as compared to normal subjects (11.6+/-0.6 microg/ml). The plasma levels of 8-epi-PGF2alpha and adiponectin were significantly correlated in MONW (r=-0.617, P<0.01) and in all (MONW+normal) (r=-0.620, P<0.01) subjects. The plasma levels of 8-epi-PGF2alpha and adiponectin were significantly correlated after adjustment for VFA in MONW subjects (F=11.042, P<0.01). The present study showed that systemic increase in oxidative stress correlates with decreased circulating levels of adiponectin in Japanese MONW men with NGT. Although correlation does not prove causation, this observation suggests that increased oxidative stress may decrease the production of adiponectin in Japanese MONW men with NGT.

Adiponectin↗
PubMed2006

Different metabolic correlations of thrombin-activatable fibrinolysis inhibitor and plasminogen activator inhibitor-1 in non-obese type 2 diabetic patients.

We investigated the plasma levels of thrombin-activatable fibrinolysis inhibitor (TAFI), plasminogen activator inhibitor-1 (PAI-1) and their relation with clinical and metabolic parameters in non-obese type 2 diabetic patients. The plasma levels of TAFI and PAI-1 were evaluated in 47 non-obese type 2 diabetic patients and 31 normal subjects. The intra-abdominal visceral and subcutaneous fat areas were measured by computed tomography (CT). The degree of insulin resistance was evaluated by the euglycemic-hyperinsulinemic clamp technique using artificial pancreas. The plasma levels of TAFI (169.0+/-108.8% versus 103.7+/-52.3%; p<0.001, mean+/-S.D.) and PAI-1 (82.7+/-54.5ng/ml versus 52.9+/-51.7ng/ml; p<0.05) were significantly higher in non-obese type 2 diabetic patients than in normal subjects. Univariate analysis showed that the plasma TAFI levels are significantly and inversely correlated with the glucose infusion rate (GIR) (r=-0.42, p<0.005) in all diabetic patients. Moreover, the plasma levels of TAFI were significantly correlated with fasting plasma glucose levels (r=0.47, p<0.001) and HbA(1c) (r=0.38, p<0.005) in all subjects. The plasma levels of PAI-1 were significantly and proportionally correlated with the visceral fat area (r=0.42, p<0.005) and body mass index (r=0.33, p<0.05). There was no significant correlation between plasma levels of TAFI and PAI-1 (r=0.04). These results show that the plasma levels of TAFI and PAI-1 differently correlate with insulin resistance and visceral fat accumulation, suggesting that different factors are implicated in the plasma elevation of TAFI and PAI-1 in non-obese type 2 diabetes mellitus.

Body Mass Index↗
PubMed2006

Deficiency of tenascin C attenuates allergen-induced bronchial asthma in the mouse.

Tenascin C (TN-C) is an extracellular matrix glycoprotein whose expression is increased in several inflammatory diseases of the lung, including bronchial asthma. However, the exact function of TN-C in the pathogenesis of lung inflammation remains unclear. In the present study, we compared the degree of bronchial asthma in wild-type and TN-C-deficient (-/-) BALB/c mice. Bronchial asthma was induced by sensitization and challenge with ovalbumin. Littermates treated with saline were used as controls. Cytokines in bronchoalveolar lavage fluid and plasma were measured by enzyme immunoassays. The number of eosinophils in the lung was significantly increased in wild-type mice compared with TN-C-knockout mice. Airway hyperreactivity, NF-kappaB activation and concentrations of monocyte chemoattractant protein-1, IL-5, IL-13, metalloproteinase-9 and immunoglobulin-E in the bronchoalveolar lavage fluid were significantly decreased in ovalbumin-sensitized/challenged TN-C-knockout mice compared with their wild-type counterparts. In vitro experiments disclosed that TN-C significantly stimulates the secretion of IL-5, IL-13, IFN-gamma and immunoglobulin-E from spleen lymphocytes. These observations suggest that TN-C is involved in the pathogenesis of bronchial asthma.

Allergens↗
PubMed2006

Features of early gastric cancer and gastric adenoma by enhanced-magnification endoscopy.

BACKGROUND: Changes to the mucosal surface of early gastric carcinomas and gastric adenomas as viewed by enhanced-magnification endoscopy with acetic acid have not been investigated thoroughly. Using this technology, we investigated the appearance of the gastric surface patterns of neoplastic and surrounding nonneoplastic mucosa. METHODS: Forty-seven consecutive patients with early gastric carcinomas or gastric adenomas underwent enhanced-magnification endoscopy following 1.5% acetic acid instillation. All biopsy specimens were taken from the area at which the enhanced-magnified endoscopic image was obtained. RESULTS: Surface patterns of gastric tumors and the surrounding mucosa were classified into five types: type I, small round pits of uniform size and shape; type II, slit-like pits; type III, gyrus and villous patterns; type IV, irregular arrangements and sizes of pattern types I, II and III; type V, destructive patterns of types I, II and III. The predominant pattern of the surrounding mucosa was type III, and most type III mucosa had characteristics of intestinal metaplasia. Although all elevated adenomas showed type II or type III surface patterns, both depressed adenomas showed type IV. Elevated carcinomas showed type III (42.9%) or type IV (57.1%) surface patterns, while depressed carcinomas showed type IV (70%) or type V (30%). Although differentiated tubular adenocarcinomas showed type III (10.3%), type IV (86.2%), or type V (3.5%) surface patterns, all of the signet-ring cell carcinomas and poorly differentiated tubular adenocarcinomas showed type V. CONCLUSIONS: Enhanced-magnification endoscopy may be useful for identifying gastric tumors and determining the extent of horizontal spread, especially in tumors of the depressed type.

Adenoma↗
PubMed2006

Morphology of hepatitis C and hepatitis B virus particles as detected by immunogold electron microscopy.

We performed indirect immunogold electron microscopy (EM) for immunological identification and characterization of hepatitis C virus (HCV). To clarify the morphology of HCV, an indirect immunogold EM of two plasma samples from patients with high HCV RNA titers was carried out using antibodies specific for the putative HCV envelope protein (E) 1. Spherical virus particles 55-65 nm in diameter with delicate spike projections were detected in the 1.14-1.16 g/ml fractions after sucrose density gradient centrifugation. Polyclonal and monoclonal antibodies to the putative HCV E1 specifically recognized these particles. In addition, immunogold EM of the samples was also performed to uncover the morphology of HCV core particles. Spherical particles 33-40 nm in diameter (average, 37 nm) were detected in the 1.22- to 1.25-g/ml fractions by conventional EM after sucrose density gradient centrifugation. Immunogold EM using rabbit polyclonal antibody (RR8) specific for the putative HCV core protein and colloidal gold-labeled goat antirabbit IgG showed binding of the gold particles with RR8. Some of the HCV core particles showed icosahedric morphology. Optical rotation technique showed that the HCV core particles exhibit sixfold symmetry and that the length of the regular hexagon side is approximately 20 nm, suggesting that they have an icosahedric structure. Further, the detection limit of the indirect immunogold EM was evaluated in 11 plasma samples from chronic hepatitis B patients with different degrees of hepatitis B virus (HBV) DNA titers using antihepatitis B surface antigen antibody. The study showed that the detection limit of virus using this method is 10(7) virions/ml.

DNA, Viral↗
PubMed2006

The ultrastructural morphology of native hepatitis B virus.

Cell lines (2.2.15 cells) capable of supporting the replication of hepatitis B virus (HBV) DNA and intact viral particles have been established by HBV DNA transfection into HepG2 cells. The purpose of this study was to determine the ultrastructural morphology of native HBV particles without purification in the culture supernatants and in sera from patients. Electron microscopy (EM) and immunogold EM of the samples were carried out using polyclonal and monoclonal anti-hepatitis B surface antigen antibodies. HBV particles in the purified samples from the culture supernatants by density-gradient centrifugation were examined to compare the morphology with that of unpurified samples. EM and immunogold EM studies demonstrated the presence of Dane particles (41.8 nm in diameter), cobra-shaped (head diameter, 42.4 nm), and horn-shaped (head diameter, 43.5 nm) particles in the culture supernatants and in the sera from two patients. The tail of the cobra-like particles had a diameter of 21.0 nm and a length of 214 nm. The hornlike particles had a long branch 20.1 nm in diameter with a length of 189 nm, and a short branch 21.4 nm in diameter with a length of 112 nm. The ratio of Dane particles and cobra- and horn-shaped particles in the supernatants was 5 : 4 : 1. After ultracentrifugation, the cobra- and horn-shaped particles completely disappeared; there were only Dane particles together with spheres of 22 nm and filaments. In conclusion, this study showed for the first time that the native replicative form of HBV is cobra- and horn-shaped.

Cell Line↗
PubMed2006

Decreased protein C activation in patients with fulminant hepatic failure.

OBJECTIVE: Abnormalities of the blood coagulation system have an influence on outcome in patients with fulminant hepatic failure (FHF). The protein C (PC) pathway is one of the main modulators of the blood coagulation system. The role of the PC pathway in FHF is not clear. In the present study, we evaluated endothelial cell injury and the grade of activated protein C (APC) generation in FHF patients. MATERIAL AND METHODS: The effect of APC on the expression of tumor necrosis factor (TNF)-alpha and monocyte chemoattractant protein (MCP)-1 from LI90 stellate cells was also evaluated. This study comprised 5 patients with FHF, 6 with acute hepatitis (AH), 12 with chronic hepatitis (CH) and 20 healthy subjects. RESULTS: The plasma concentrations of thrombin-antithrombin complex and thrombomodulin were significantly increased in FHF patients compared with those in AH patients and healthy subjects. The circulating levels of activated protein C-protein C inhibitor (APC-PCI) complex and the APC-PCI/PC ratio were significantly decreased in patients with FHF compared to healthy controls. APC significantly inhibited in vitro the expression of TNFalpha and MCP-1 from LI90 stellate cells. CONCLUSIONS: This study demonstrated enhanced endothelial cell injury in association with decreased PC activation and hypercoagulability in FHF.

Antithrombin III↗
PubMed2006

siRNA-resistance in treated HCV replicon cells is correlated with the development of specific HCV mutations.

RNA interference (RNAi) has been extremely effective against hepatitis C viral (HCV) gene expression in short-term cell culture. Our aim was to determine whether long-term RNAi might result in HCV-resistant mutants. Huh7 HCV subgenomic replicon cells were transfected with short interfering RNAs (siRNAs). HCV-RNA was quantified by real-time RT-PCR, and HCV NS5A levels were assayed by Western blots using specific antibody. Treatment with HCV-siRNA resulted in a 50% inhibition of HCV-RNA levels compared with pretreatment levels after 4 weeks (P < 0.05). HCV-RNA returned to 85% of pretreatment levels after cessation of HCV-siRNA treatment. Sequencing of the HCV-siRNA target and upstream region was performed on 10 colonies from subcloning using PCR products, each before, during and after siRNA treatment. All colonies except one from HCV-siRNA-treated cells during and after treatment had mutations. There were no mutations in the HCV-siRNA target region following control HBV-siRNA treatment. Subcloned replicon cells containing the point mutations in the target region were found to be resistant to HCV-siRNA inhibitory effects. In conclusion, even after 4 weeks of treatment of replicon cells with HCV-siRNA, HCV-RNA and HCV-NS5A protein expression could not be completely eliminated. HCV replicons isolated during or after treatment were associated with mutations in the siRNA target region, while controls were not.

Base Sequence↗
PubMed2006

Role of transferrin receptor 2 in hepatic accumulation of iron in patients with chronic hepatitis C.

BACKGROUND AND AIM: Iron deposition in the liver is a common finding in patients with chronic hepatitis C (CH-C). The mechanism of this hepatic accumulation of iron is not completely understood. This study assessed if the protein expression of transferrin receptor 2 (TfR2) is upregulated in the liver of patients with CH-C and if TfR2 protein mediates iron accumulation during hepatitis C virus (HCV) infection. METHOD: Liver specimens from patients with CH-C that underwent interferon (IFN) therapy (n=23) and from patients with CH-B (n=18) were evaluated. Hepatic expression of TfR2 protein was analyzed by immunohistochemistry. Total hepatic iron score (THIS) was evaluated by Prussian blue staining. RESULTS: TfR2 protein was expressed in the cell membrane and cytosol of hepatocytes. Cytosol TfR2 protein was found to co-localize with Tf. THIS (P=0.0198) and hepatic TfR2 (P=0.0047) expression were significantly higher in CH-C than in CH-B. The change in THIS values (rho=0.580, P=0.0079) and the grade of histological activity (rho=0.444, P=0.0373) were significantly correlated with changes in TfR2 expression after IFN therapy. CONCLUSIONS: The protein expression of TfR2 is significantly associated with iron deposition in the liver in patients with CH-C. HCV infection may affect the hepatic expression of TfR2, leading to iron accumulation in the liver.

Adult↗
PubMed2006

Increased lipid peroxidation in patients with non-alcoholic fatty liver disease and chronic hepatitis C as measured by the plasma level of 8-isoprostane.

BACKGROUND: Oxidative stress plays an important role in the pathogenesis of chronic liver diseases. The plasma level of 8-isoprostane, a product of lipid peroxidation, is a marker of oxidative stress in vivo. The aim of the present study was to clarify whether the degree of lipid peroxidation, as measured by the plasma level of 8-isoprostane, influences the progression of chronic liver diseases and hepatocarcinogenesis. METHODS: Plasma 8-isoprostane levels were investigated in 14 patients with non-alcoholic fatty liver disease (NAFLD), 75 with chronic hepatitis C (CH-C), 14 with cured CH-C, 14 with HCV-positive hepatocellular carcinoma (HCC-C) and 38 healthy volunteers. 8-Isoprostane was measured by enzyme immunoassay after affinity column purification. RESULTS: Plasma 8-isoprostane was significantly elevated in NAFLD (11.9 [3.8-56.8] pg/mL), CH-C (10.1 [4.2-134.5] pg/mL) as compared to controls (6.3 [3.6-11.1] pg/mL). Plasma 8-isoprostane values were positively correlated with body mass index in NAFLD (P < 0.05) and with total cholesterol in cured CH-C (P < 0.01). 8-Isoprostane levels were not significantly related to sex, age, biochemical data or iron metabolism markers in all liver diseases. In addition, after the administration of peg-interferon, the values of 8-isoprostane improved in almost all patients, reaching values of healthy subjects. CONCLUSIONS: 8-Isoprostane values are elevated in patients with NAFLD and CH-C as compared to healthy controls. Oxidative stress caused by increased lipid peroxidation is involved in the pathogenesis of NAFLD and CH-C.

Adolescent↗