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Y Shiratori

Publications and source records attributed to Y Shiratori.

At least 37 records · Page 2Linked to original sources
PubMed2001

Distinct mechanism of Helicobacter pylori-mediated NF-kappa B activation between gastric cancer cells and monocytic cells.

NF-kappaB is a critical regulator of genes involved in inflammation. Gastric epithelial cells and macrophages are considered the main sources of pro-inflammatory cytokines. We investigated NF-kappaB activation by Helicobacter pylori in MKN45 gastric epithelial cells and THP-1 monocytic cells. Although, cag pathogenicity island (PAI)-positive H. pylori (wild type) activated NF-kappaB in both cells, isogenic mutant of cagE (DeltacagE) activated it only in THP-1 cells. Supernatant from the wild type culture could activate NF-kappaB in THP-1 cells but not in MKN45 cells. High density cDNA array analysis revealed that mRNA expression of NF-kappaB-regulated genes such as interleukin (IL)-8, tumor necrosis factor-alpha (TNFalpha), and IL-1beta was significantly up-regulated by the wild type in both cells, whereas it was up-regulated by DeltacagE only in THP-1 cells. Experiments using CD14-neutralizing antibody and IL-1 receptor-associated kinase (IRAK) assay showed that both wild type and DeltacagE H. pylori activated NF-kappaB through CD14 and IRAK in THP-1 cells but not in MKN45 cells. Macrophages from C3H/HeJ mice carrying point mutation in the Toll-like receptor 4 (TLR4) gene showed decreased NF-kappaB activation and TNFalpha secretion compared with C3H/HeN mouse macrophage when treated with H. pylori. In conclusion, H. pylori-induced NF-kappaB activation in epithelial cells is dependent on cag PAI and contact but does not involve CD14 and IRAK, whereas in macrophage/monocytic cells it is independent of cag PAI or contact but involves CD14 and TLR4.

Animals↗
PubMed2001

Design and synthesis of novel benzofurans as a new class of antifungal agents targeting fungal N-myristoyltransferase. Part 1.

Potent and selective Candida albicans N-myristoyltransferase (CaNmt) inhibitors have been identified through optimization of a lead compound 1 discovered by random screening. The inhibitor design is based on the crystal structure of the CaNmt complex with compound (S)-3 and structure-activity relationships (SARs) have been clarified. Modification of the C-4 side chain of 1 has led to the discovery of a potent and selective CaNmt inhibitor 11 (RO-09-4609), which exhibits antifungal activity against C. albicans in vitro.

Acyltransferases↗
PubMed2001

Reduced C-terminal Src kinase activity is correlated inversely with pp60(c-src) activity in colorectal carcinoma.

BACKGROUND: Specific kinase activity of the proto-oncogene product pp60(c-src) is reported to be elevated in patients with carcinoma of the colon, and a novel cytoplasmic protein-tyrosine kinase, C-terminal Src kinase (Csk), has been found to inactivate the members of the Src family protein-tyrosine kinase. In this study, Csk activity and pp60(c-src) activity were examined in colorectal tumors as well as in colon carcinoma cell lines. METHODS: Colorectal carcinoma tissue and adjacent nonneoplastic tissue from 24 patients, from 8 colon carcinoma cell lines, and from 1 normal colon cell line were used. The levels of pp60(c-src) and Csk in colorectal tissue and cell lines were analyzed by Western and/or Northern blot analysis, and their kinase activity levels were measured by in-gel kinase assay. RESULTS: In the samples from 24 patients with colorectal carcinoma, pp60(c-src) kinase activity and protein levels were increased by 7.8 +/- 0.55 and 2.6 +/- 0.13 times the control levels, respectively. Conversely, the Csk protein level and its kinase activity were reduced by 0.53 +/- 0.08 and 0.53 +/- 0.09 times the control levels, respectively. pp60(c-src) kinase activity was correlated inversely with Csk activity (correlation coefficient = -0.71; P < 0.0001). Of the cell lines, pp60(c-src) kinase activity and protein levels, respectively, were 7.4 +/- 1.22 and 1.86 +/- 0.28 times greater than normal control levels. Csk protein level and kinase activity, respectively, were 0.54 +/- 0.13 and 0.52 +/- 0.11 times less normal control levels and were correlated with mRNA amount. CONCLUSIONS: Csk mRNA, protein, and its kinase activity were reduced in colorectal carcinoma and were correlated with pp60(c-src) kinase activity level. The reduced activity of Csk may be involved in the transformation of a subset of colorectal carcinoma.

Aged↗
PubMed2001

cDNA microarray analysis of Helicobacter pylori-mediated alteration of gene expression in gastric cancer cells.

Helicobacter pylori infection stimulates several intracellular signaling pathways and is accompanied by increased gene expression in gastric epithelial cells. High-density cDNA microarray was used to characterize the mRNA expression profile of genes in human gastric cancer cells (MKN45, AGS) cocultured with H. pylori. Coculture with cag pathogenicity island (PAI)-positive H. pylori (wild-type) significantly up-regulated mRNA expression in 8 of 2304 genes tested. In 6 (interleukin-8, I(kappaB)alpha, A20, ERF-1, keratin K7, glutathione peroxidase) of the 8 genes, up-regulation was confirmed by RT-PCR. In coculture with isogenic cagE-negative mutant ((Delta)cagE), which encodes a type IV secretion system with other genes in the cag PAI, no significant up-regulation was found. We further analyzed the role of A20. Transfection of expression vector encoding A20 resulted in an inhibition of H. pylori-mediated NF-kappaB activation, indicating that H. pylori-mediated A20 expression could be a negative regulator of NF-kappaB activation. Taken together, these results indicate the importance of microarray technology as a tool for analyzing the complex interplay between H. pylori and the host.

Adenocarcinoma↗
PubMed2001

Simple quantitative assay of alpha-fetoprotein mRNA in liver tissue using the real-time detection polymerase chain reaction assay - its application for clinical use.

Alpha-feto protein (AFP) mRNA levels increase in hepatocellular carcinoma (HCC) cells as compared with non-neoplastic tissue. Therefore, detection of AFP mRNA in blood nuclear cells is useful for the evaluation of treatment efficacy and prognosis of HCC. In this study, simple and reproducible methods were developed to quantify AFP mRNA using the real-time RT-PCR assay (Taq Man assay). By using in vitro synthesized AFP and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) RNA, the sensitivity and dynamic range of the RT-PCR assay were established. AFP mRNA in both HCC and non-neoplastic tissue, as well as in cell lines, were measured using this assay system. The expression of the AFP mRNA level was normalized using the GAPDH house keeping gene product as an endogenous reference. AFP and GAPDH mRNA can be quantified in the range of 10-10(8) copies when using this quantitative assay. Among HCC cell lines, Huh 7 and HepG2 cells, respectively, represented 1.5x10(6) and 6.0x10(5) AFP mRNA/10(6) GAPDH mRNA, in contrast to 6, 23 and 230 AFP mRNA/10(6) GAPDH mRNA for HLE, HLF and PLC/PRF/5 cells, respectively. Other cell lines derived from stomach, pancreas, and colon cancers have 10 AFP mRNA copies/10(6) GAPDH mRNA. In liver tissue from patients with chronic hepatitis, and the non-neoplastic portion of the liver from HCC patients, AFP mRNA distributes from 2.5x10(3) to 5.8x10(4)/10(6) GAPDH transcripts. In contrast, AFP mRNA in tumor cells were more than 100-fold higher than that found in corresponding non-neoplastic portions in two patients who had a high level of AFP in serum. The establishment of the TaqMan quantifying system for AFP mRNA may have important clinical implications.

Journal Article↗
PubMed2001

Target gene therapy for alpha-fetoprotein-producing hepatocellular carcinoma by E1B55k-attenuated adenovirus.

Gene therapy using replication-competent adenovirus that selectively propagates in tumor cells may be an effective treatment for cancer. We developed an adenovirus that would be replication specific for hepatocellular carcinoma (HCC). Based on our finding that the E1B55k-deficient adenovirus was able to replicate in human primary hepatocytes, we therefore designed an adenovirus carrying E1A and attenuated E1B gene driven by the alpha-fetoprotein promoter (Adv-AFP-E1AdB), thus restricting the replication specificity in AFP-producing HCC. Replication of Adv-AFP-E1AdB in primary hepatocytes was practically negligible 4 days after infection. Although Adv-AFP-E1AdB replicated slowly in AFP-producing HCC, it efficiently destroyed HCC cells independent of their p53 status. Experiments were conducted in vivo using systemic administration of Adv-AFP-E1AdB and we observed tumor size reduction in nude mice having liver cancer. The use of replication-competent adenovirus deficient of the E1B gene coupled to an AFP-targeting strategy may be a safe and efficacious treatment for HCC.

Adenoviridae↗
PubMed2001

Hepatitis C virus core protein activates nuclear factor kappa B-dependent signaling through tumor necrosis factor receptor-associated factor.

Hepatitis C virus (HCV) core protein, a viral nucleocapsid, has been shown to affect various intracellular events including the nuclear factor kappaB (NF-kappaB) signaling supposedly associated with inflammatory response, cell proliferation, and apoptosis. In order to elucidate the effect of HCV core protein on the NF-kappaB signaling in HeLa and HepG2 cells, a reporter assay was utilized. HCV core protein significantly activated NF-kappaB signaling in a dose-dependent manner not only in HeLa and HepG2 cells transiently transfected with core protein expression plasmid, but also in HeLa cells induced to express core protein under the control of doxycycline. HCV core protein increased the DNA binding affinity of NF-kappaB in the electrophoretic mobility shift assay. Acetyl salicylic acid, an IKKbeta-specific inhibitor, and dominant negative form of IKKbeta significantly blocked NF-kappaB activation by HCV core protein, suggesting HCV core protein activates the NF-kappaB pathway mainly through IKKbeta. Moreover, the dominant negative forms of TRAF2/6 significantly blocked activation of the pathway by HCV core protein, suggesting HCV core protein mimics proinflammatory cytokine activation of the NF-kappaB pathway through TRAF2/6. In fact, HCV core protein activated interleukin-1beta promoter mainly through NF-kappaB pathway. Therefore, this function of HCV core protein may play an important role in the inflammatory reaction induced by this hepatotropic virus.

Cell Line↗
PubMed2001

Des-gamma-carboxy prothrombin as a useful predisposing factor for the development of portal venous invasion in patients with hepatocellular carcinoma: a prospective analysis of 227 patients.

BACKGROUND: Portal venous invasion (PVI) in patients with hepatocellular carcinoma (HCC) is an important factor affecting prognosis. The objective of this study was to elucidate predisposing factors for the development of PVI. METHODS: Two hundred twenty-seven patients with HCC who did not show PVI and who received percutaneous ethanol injection therapy and/or microwave coagulation therapy at the time of their first hospital admission were enrolled between 1994 and 1996. After their HCC was treated, the patients were followed for a mean of 19 months. For the detection of HCC recurrence and/or development of PVI, ultrasonography was performed every 3 months, a computed tomography (CT) scan was performed every 6 months, and the biochemical parameters of the patients were measured every month. PVI was defined as protrusion of the tumor into the first and/or second branch or into the main trunk of the portal vein. RESULTS: Of the 227 patients, 24 (11%) later developed PVI. Tabular analysis was performed on these 24 patients and indicated that tumor size, albumin, total bilirubin, prothrombin time, alpha-fetoprotein (AFP) level, and des-gamma-carboxy prothrombin (DCP) level differed significantly between the time of initial admission and the time of PVI development. A univariate analysis performed on the 227 patients indicated that an increase in the numbers of tumors, the histologic tumor grade (differentiation), the AFP level, and the DCP level at the time of initial diagnosis of HCC had a significant correlation with the later development of PVI; and a stepwise, multivariate Cox regression analysis revealed that the DCP level was the strongest predisposing factor (P < 0.0010; risk ratio = 5.65) followed by the histologic grade of tumor differentiation. CONCLUSIONS: The results suggest that the serum DCP level is the most useful predisposing clinical parameter for the development of PVI.

Adult↗
PubMed2001

Usefulness of MR imaging in the postsurgical monitoring of gallbladder cancer in a patient with bile duct cancer that developed 7 years after resection of mucinous adenocarcinoma of the gallbladder.

We encountered a case of left hepatic duct cancer that developed 7 years after surgical resection of early-stage adenocarcinoma of the gallbladder. A 65-year-old woman was hospitalized with high fever and general fatigue. She also had elevated serum levels of alkaline phosphatase, gamma-glutamyltranspeptidase, and carbohydrate antigen 19-9. Seven years earlier, she had undergone extended cholecystectomy and resection of the extrahepatic bile duct for early-stage mucinous adenocarcinoma of the gallbladder. Conventional examinations did not reveal any responsible lesions. Magnetic resonance (MR) cholangiography, however, showed a tumor obstructing the left hepatic duct, and dynamic MR images revealed multiple foci of bacterial abscess in the liver. Surgically resected tissue again revealed mucinous adenocarcinoma. The present case is rare in that metachronous mucinous adenocarcinoma of the biliary system occurred after a long interval. This case suggests the usefulness of MR imaging in the postsurgical monitoring of patients with gallbladder carcinoma.

Adenocarcinoma, Mucinous↗
PubMed2001

Hepatocellular carcinoma depicted as hypoattenuation on CT hepatic arteriography (CTA) and hyperattenuation on CT during arterial portography (CTAP).

We report a 68-year-old man with three nodules of hepatocellular carcinoma (HCC) in a cirrhotic liver; the largest nodule was 3.0cm in diameter. The nodules showed hypoattenuation on computed tomography (CT) hepatic arteriography (CTA) and hyperattenuation on CT during arterial portography (CTAP), indicating that the dominant vascularity of the HCC nodules may have been the portal vein. A biopsy specimen obtained from the nodules showed well differentiated HCC (Edmondson-Steiner grade I). The imaging findings of the nodules on both CTA and CTAP are unusual, in spite of the rather large size, so this seemed suggestive of the hemodynamic properties of relatively large nodules of well differentiated HCC.

Aged↗
PubMed2001

Power Doppler signals after percutaneous ethanol injection therapy for hepatocellular carcinoma predict local recurrence of tumors: a prospective study using 199 consecutive patients.

BACKGROUND/AIMS: This study was prospectively conducted to elucidate the relationship between pre-/post-treatment power Doppler signals of hepatocellular carcinoma (HCC) and local recurrence. METHODS: One hundred ninety-nine consecutive patients with 359 HCC lesions receiving percutaneous ethanol injection therapy (PEIT) as a first-line option were enrolled. Arterial power Doppler signals in the tumor were found in 130 nodules, but not detected in 229. After confirmation of complete tumor necrosis on dynamic CT, Doppler signals in nodules were re-evaluated. Patients received periodical examinations to detect HCC recurrence. RESULTS: Local HCC recurrence was observed in 36 lesions; 22%(28/130) of the pretreatment signal positive lesions, in contrast to 3.5% (8/229) of the pretreatment signal negative lesions (P < 0.01). Out of 130 signal positive nodules, signals disappeared in 120 (92%) after PEIT, but were present in ten (8%). During the 25-month follow up, local recurrence was detected in 19 (16%) from the former, in contrast to nine (90%) from the latter (P < 0.001). Uni- and multivariate Cox analysis revealed that the presence of pre-/post-treatment power Doppler signals, histological differentiation and tumor number were independent factors for local recurrence. However, 3-year recurrence rate of new lesions was 51%, but no predictors were identified. CONCLUSIONS: Residual Doppler signals in tumor after PEIT were related to the local HCC recurrence.

Adult↗
PubMed2001

Extensive mesenteric vein and portal vein thrombosis successfully treated by thrombolysis and anticoagulation.

Mesenteric vein thrombosis is generally difficult to diagnose and can be fatal. A case of extensive thrombosis of the mesenteric and portal veins was diagnosed early and successfully treated in a 26-year-old man with Down syndrome who was admitted to hospital because of abdominal pain, severe nausea and high fever. Ultrasonography revealed moderate ascites, and there was minimal flow in the portal vein (PV) on the Doppler examination. Computed tomography (CT) showed remarkable thickening of the walls of the small intestine and extensive thrombosis of the mesenteric, portal and splenic veins. Because neither intestinal infarction nor peritonitis was seen, combined thrombolysis and anticoagulation therapy without surgical treatment was chosen. Urokinase was administered intravenously and later through a catheter in the superior mesenteric artery. Heparin and antibiotics were given concomitantly. The patient's symptoms and clinical data improved gradually. After 10 days, CT revealed that collateral veins had developed and the thrombi in the distal portions of the mesenteric veins had dissolved, although the main trunk of the PV had not recanalized. The only risk factor of thrombosis that was detected was decreased protein S activity.

Adult↗
PubMed2001

Thoracoscopic thermal ablation therapy for hepatocellular carcinoma located beneath the diaphragm.

BACKGROUND AND STUDY AIMS: Percutaneous interstitial thermal ablation therapy effectively treats hepatocellular carcinoma (HCC) that can be visualized on percutaneous ultrasonography. However, when the tumor is located just under the top of the diaphragm, visualization can be difficult with conventional ultrasonographic examination. There are also problems concerning complete tumor ablation. We performed thoracoscopic thermal ablation therapy for HCC located just beneath the diaphragm in nine patients with advanced liver cirrhosis. PATIENTS AND METHODS: Eight patients underwent thoracoscopic microwave coagulation therapy, and one patient underwent thoracoscopic radiofrequency ablation therapy. RESULTS: Despite the poor hepatic reserve, postoperative recovery after thoracoscopic thermal ablation therapy was rapid in all patients, without deterioration of hepatic function. CONCLUSIONS: This preliminary study suggests that the new technique of thoracoscopic thermal ablation therapy is a less invasive optional therapy for HCC located in segments VII or VIII in cirrhotic patients.

Aged↗
PubMed2001

Clarithromycin-based triple therapy for non-resistant Helicobacter pylori infection. How long should it be given?

BACKGROUND: We have previously reported mixed infection with wild-type (sensitive) and mutant (resistant) Helicobacter pylori strains using a PCR-based preferential homo-duplex formation assay (PCR-PHFA) to detect gene mutations associated with clarithromycin resistance. Half of the cases with mixed infection were determined as sensitive by conventional MIC assessment and yet failed to respond to clarithromycin-based therapy. The aim of this study is to assess the efficacy of clarithromycin-based triple therapy in patients infected exclusively with wild-type strains as determined by PCR-PHFA. METHODS: Ninety patients who had pure wild-type H. pylori infection were randomly assigned to receive clarithromycin (200 mg b.i.d.), amoxicillin (500 mg q.i.d.) and lansoprazole (30 mg b.i.d.) for either 5 days or 7 days (n = 48 and n = 42, respectively). The outcome of eradication was assessed by [13C] urea breath test. RESULTS: Eradication was achieved in 36/48 (75%) versus 39/42 (93%) by intention-to-treat analysis (P = 0.02), and in 36/45 (80%) versus 39/40 (98%) by per protocol analysis (P = 0.01), for the 5-day and 7-day protocols, respectively. Compliance and the incidence of untoward effects were similar in both groups. CONCLUSIONS: Seven-day administration is necessary and sufficient for the triple therapy with clarithromycin, amoxicillin and lansoprazole in patients with pure wild-type H. pylori infection.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2001

Frameshift mutations at mononucleotide repeats in RAD50 recombinational DNA repair gene in colorectal cancers with microsatellite instability.

To identify additional genes targeted for microsatellite instability (MSI), we search for human genes which contain mononucleotide repeats in their coding region, selected 7 genes (RAD50, DNA-PKcs, FLASH, Apaf-1, XPG, CtIP, and MLSN1), and analyzed frameshift mutations in them. Here we report that 60% (3 out of 5) of human colorectal cancer cell lines exhibiting a high frequency of MSI (MSI-H) and 46% (6 out of 13) of MSI-H primary colorectal tumors had mutations in the (A)9 repeat of RAD50 recombinational repair gene. In contrast, no frameshift mutations were found in any of the 5 MSI-negative colorectal cancer cell lines, 8 colorectal tumors exhibiting a low frequency of MSI (MSI-L), or 28 MSI-negative colorectal tumors. No mutations were found in the mononucleotide repeats of 6 other genes, even in MSI-H cancers. These results suggest that RAD50 frameshift mutations may play a role in the tumorigenesis of MSI-H colorectal cancers.

Colorectal Neoplasms↗
PubMed2001

Determination of Helicobacter pylori virulence by simple gene analysis of the cag pathogenicity island.

Nucleic acid amplification was performed for five loci in the cag pathogenicity island (PAI) of Helicobacter pylori (comprising cagA, the cagA promoter region, cagE, cagT, and the left end of cagII [LEC]), and gastric inflammation in patients was evaluated. Of 204 H. pylori isolates from Japanese patients (53 with peptic ulcer, 55 with gastric cancer, and 96 with chronic gastritis), 197 (96.6%) were positive for all five loci. Two isolates (1%) were negative for all five loci, and five isolates (2.4%) were positive for only cagA and LEC. These latter seven isolates were all from patients with mild chronic gastritis. Neutrophil infiltration in gastric mucosa was significantly milder in patients infected with partially or totally deleted-PAI strains than in those with intact-PAI strains. The cagE gene was a more accurate marker of an intact cag PAI than the cagA gene, and cagE seemed to be more useful in discriminating between H. pylori strains causing different rates of disease progression.

Adult↗