Biomedical subjects

Norio Hayashi

Publications and source records attributed to Norio Hayashi.

At least 37 records · Page 2Linked to original sources

PubMed2005

Endothelin-1, an ulcer inducer, promotes gastric ulcer healing via mobilizing gastric myofibroblasts and stimulates production of stroma-derived factors.

Endothelin (ET)-1 is a potent inducer of peptic ulcers. The roles of ET-1 in ulcer healing, however, have remained unclear, and these were investigated in mice. Gastric ulcers were induced in mice by serosal application of acetic acid. Three days later, mice were given a neutralizing ET-1 antibody or nonimmunized serum. The ulcer size, amount of fibrosis and myofibroblasts, and localization of ET-1 and ET(A/B) receptors were analyzed. To elucidate the mechanisms underlying the effects of ET-1, we examined the proliferation, migration, and release of growth and angiogenic factors in gastric myofibroblasts with or without ET-1. The expression of prepro-ET-1 (an ET-1 precursor) and ET-converting enzyme-1 was examined in gastric myofibroblasts using RT-PCR. Immunoneutralization of ET-1 delayed gastric ulcer healing. The areas of fibrosis and myofibroblasts were smaller in the anti-ET-1 antibody group than in the control. ET-1 was expressed in the gastric epithelium, myofibroblasts, and other cell types. ET(A) receptors, but not ET(B) receptors, were present in myofibroblasts. ET-1 increased proliferation and migration of gastric myofibroblasts. ET-1 stimulated the release of hepatocyte growth factor, VEGF, PGE(2), and IL-6 from gastric myofibroblasts. mRNA for prepro-ET-1 and ET-converting enzyme-1 was also expressed. ET-1 promotes the accumulation of gastric myofibroblasts and collagen fibrils at gastric ulcers. ET-1 also stimulates migration and proliferation of gastric myofibroblasts and enhances the release of growth factors, angiogenic factors, and PGE(2). Thus ET-1 has important roles not only in ulcer formation but also in ulcer healing via mobilizing myofibroblasts and inducing production of stroma-derived factors.

Angiogenesis Inducing Agents↗

PubMed2005

Pamidronate induced anti-proliferative, apoptotic, and anti-migratory effects in hepatocellular carcinoma.

BACKGROUND/AIMS: The small GTPase of Ras and Rho families are widely involved in human tumorgenesis and metastasis. It has recently been reported that pamidronate inhibits the mevalonate pathway, which is required for the prenylation of the small GTPase. We demonstrated a possible beneficial use of pamidronate in the treatment of hepatocellular carcinoma (HCC). METHODS: The effect of pamidronate on cell proliferation was analyzed with five hepatoma cell lines using MTT assay. Apoptosis was evaluated by staining with DAPI and a histon ELISA assay. A cell migration assay was performed using the Modified Boyden Chamber. To analyze anti-proliferation effect of pamidronate in vivo, tumor volumes were monitored with the intraperitoneal injection of pamidronate after subcutaneous inoculation of PLC/PRF/5 cells into nude mice. RESULTS: Pamidronate inhibited cell growth for all hepatoma cell lines. The amount of membrane associated Ras and phosphorylated extracellular signal-regulated kinase 2 (ERK 2) were reduced after pamidronate treatment. Pamidronate increased apoptosis and cleavage of Caspase-3, and -9. Pamidronate suppressed membrane associated RhoA and cell motility. In vivo, tumor volumes were significantly suppressed by pamidronate at three weeks (P<0.03). CONCLUSIONS: We conclude that pamidronate has therapeutic potential in inducing anti-proliferative, apoptotic, and anti-migratory effects in HCC.

Animals↗

PubMed2005

Viral covalently closed circular DNA in a non-transgenic mouse model for chronic hepatitis B virus replication.

BACKGROUND/AIMS: The lack of small animal models supporting chronic hepatitis B virus (HBV) infection impedes the assessment of anti-viral drugs in the whole animal. Although transgenic mice have been used for this purpose, these models are clearly different from natural infection, because HBV is produced from the integrated HBV sequence harbored in all hepatocytes. METHODS: Balb/cA nude mice were hydrodynamically injected with a plasmid having 1.5-fold over-length of HBV DNA and analyzed for HBV replication. RESULTS: Hydrodynamically injected mice showed substantial levels of antigenemia and viremia for more than 1 year. Covalently closed circular DNA (cccDNA), the template of viral replication in natural infection, was produced in the livers and was critically involved in the long-term HBV production, because disruption of the pol gene of the inoculated DNA resulted in transient expression of HBV genes for less than 2 months. Administration of the IFNalpha gene transiently suppressed HBV DNA replication, but was not capable of eliminating HBV in this model. CONCLUSIONS: In vivo gene transfer of a plasmid encoding HBV DNA can establish chronic viral replication in mice, which involves, at least in part, new synthesis of the HBV cccDNA episome, thus recapitulating a part of human HBV infection.

Animals↗

PubMed2005

Efficacy of lamivudine for preventing hepatocellular carcinoma in chronic hepatitis B: A multicenter retrospective study of 2795 patients.

A retrospective survey of Japanese patients histologically diagnosed with chronic hepatitis B was conducted to determine the effectiveness of lamivudine in preventing hepatocellular carcinoma (HCC). Of the 2795 patients who satisfied criteria for analysis after treatment from any of 30 medical institutions, 657 had received lamivudine and the remaining 2138 had not. A Cox regression model with liver biopsy as the starting point revealed seven factors related to HCC: lamivudine therapy, gender, family clustering of hepatitis B, age at liver biopsy, hepatic fibrosis stage, serum albumin level, and platelet count. In a matched case-controlled study, 377 patients in a lamivudine-treated group and 377 matched patients in a non-treated group were selected based on their propensity scores. The mean follow-up period was 2.7 years in the lamivudine group and 5.3 years in the control group. In the lamivudine group, HCC occurred in four patients (1.1%) with an annual incidence rate of 0.4%/(patient/year), whereas in the control group HCC occurred in 50 patients (13.3%) for a rate of 2.5%/(patient/year). A comparison of the cumulative HCC incidence between the two groups by the Kaplan-Meier method showed a significantly lower incidence of HCC in the lamivudine group (p<0.001). These findings suggest that lamivudine effectively reduces the incidence of HCC in patients with chronic hepatitis B.

Journal Article↗

PubMed2005

Impairment of natural killer cell and dendritic cell functions by the soluble form of MHC class I-related chain A in advanced human hepatocellular carcinomas.

BACKGROUND/AIMS: MHC class I-related chain A (MICA), a human ligand of natural killer (NK) cell stimulatory receptor NKG2D, is expressed in human hepatocellular carcinomas (HCC). Earlier research demonstrated that the soluble form of MICA (sMICA) is released from some types of tumors, but its presence and role in HCC was not determined. METHODS: Serum sMICA was studied in 26 patients with HCC. In vitro experiments were performed to examine the impact of sMICA on NK cell expression of NKG2D and subsequent dendritic cell (DC) activation. RESULTS: The levels of sMICA were frequently elevated in patients with advanced HCC. The elevation of sMICA was associated with down-regulated NKG2D expression and impaired activation of NK cells. In vitro experiments revealed that sMICA derived from advanced HCC was responsible for down-modulation of NKG2D expression and NK cell functions. NK cells upon stimulation of human hepatoma cells induced maturation of DC and enhanced the allostimulatory capacity of DC; maturation and activation of DC were completely abolished when NK cells were pre-treated with sMICA-containing serum. CONCLUSIONS: sMICA is present in sera of patients with advanced HCC and may serve as a tumor evasion mechanism by negatively modulating both innate and adaptive immunity.

Adult↗

PubMed2005

[Study of automated segmentation of the cerebellum and brainstem on brain MR images].

MR imaging is an important method for diagnosing abnormalities of the brain. This paper presents an automated method to segment the cerebellum and brainstem for brain MR images. MR images were obtained from 10 normal subjects (male 4, female 6; 22-75 years old, average 31.0 years) and 15 patients with brain atrophy (male 3, female 12; 62-85 years of age, average 76.0 years). The automated method consisted of the following four steps: (1) segmentation of the brain on original images, (2) detection of an upper plane of the cerebellum using the Hough transform, (3) correction of the plane using three-dimensional (3D) information, and (4) segmentation of the cerebellum and brainstem using the plane. The results indicated that the regions obtained by the automated method were visually similar to those obtained by a manual method. The average rates of coincidence between the automated method and manual method were 83.0+/-9.0% in normal subjects and 86.4+/-3.6% in patients.

Adult↗

PubMed2005

Juvenile hepatocellular carcinoma with congestive liver cirrhosis.

A case of juvenile hepatocellular carcinoma (HCC) with congestive liver cirrhosis is reported. The patient was a 21-year-old woman. She had been diagnosed as having transposition of the great arteries, type 2, in 1978. She underwent the Mustard operation, but suffered from chronic heart failure. In 1995, she experienced abdominal pain and underwent examination. The laboratory data were normal, except for elevated total bilirubin (5.2 mg/dl). Blood examinations were performed at frequent intervals, and the total bilirubin level fluctuated between 0.9 and 8.1 mg/dl over the next 4 years, but the transaminase level remained normal. In 1999, she experienced abdominal pain again and was admitted to our hospital. Computed tomography showed four space-occupying lesions in the liver; 45 mm, 20 mm, 12 mm, and 10 mm in size. She was diagnosed as having HCC, and transcatheter arterial chemoembolization and percutaneous ethanol injection therapy were performed. Histology of the cancerous and the noncancerous liver tissue revealed HCC, moderately differentiated type, in cirrhotic liver with congestion. This patient had no background factors of liver disease, except for liver congestion, associated with the chronic heart failure. Because most patients with cardiac cirrhosis die of cardiac disease, only a small number of these patients develop liver failure. However, the incidence of HCC in patients with congestive liver disease is likely to increase in the future, as survival time is prolonged with the advances in treatment for chronic heart failure. Therefore, patients with congestive liver disease should be followed, taking into account the possibility of HCC.

Adult↗

PubMed2005

Gastro-protective agent rebamipide induces cyclooxygenease-2 (COX-2) in gastric epithelial cells.

Cyclooxyngease-2 (COX-2) is a key enzyme in prostaglandin (PG) synthesis, and COX-2 induction plays an important role in the healing of gastric ulceration. Rebamipide is a gastro-protective agent and attenuates the activity of neutrophils. A number of reports have shown that rebamipide treatment increases PG production in the gastric mucosa {in vivo}. Although its clinical significance in ulcer healing has been demonstrated, {in vitro} evidence remains to be accumulated. Non-transformed rat gastric mucosal cells (RGM1 cells) were stimulated with rebamipide. RT-PCR and Western blot analysis revealed time and dose-dependent transcriptional and translational stimulation of COX-2. PGE(2) was also produced dose-dependently. However, marked COX-2 induction by rebamipide was transient and lasted less than 24 hr. COX-1 expression was unaltered by rebamipide. Reporter assay results confirmed the stimulation of Cox-2 promoter activity by rebamipide. In conclusion, this study provides {in vitro} evidence that rebamipide transcriptionally induces COX-2 and supports the rationale for its clinical use.

Alanine↗

PubMed2005

Impact of daily high-dose IFNalpha-2b plus ribavirin combination therapy on reduction of ALT levels in patients with chronic hepatitis C with genotype 1 and high HCV RNA levels.

The possibility of delaying progression to hepatocellular carcinoma in chronic hepatitis C patients with genotype 1 and high viral titers with baseline ALT levels of >/=50IU/L was examined by administration of IFN plus ribavirin combination therapy using ALT normalization as index and IFN monotherapy as control. The rate of sustained ALT normalization (ALT normal at 24 weeks after the end of treatment) was 28.1% with combination therapy and 10.5% with IFN monotherapy (P=0.001). Furthermore, the number of patients with sustained viral response (SVR) and with sustained ALT normalization in non-SVR patients was also significantly higher in the combination therapy versus monotherapy group. Mean ALT values during treatment and for 6 months after the end of treatment were significantly lower with combination therapy versus monotherapy even in virological nonresponders, as well as significantly lower during the post-treatment observation period in patients who relapsed after the end of treatment. Since increase in the rate of sustained ALT normalization and SVR were successfully achieved, inhibition of progression to hepatocellular carcinoma should be studied with long-term IFN and ribavirin combination therapy.

Journal Article↗

PubMed2005

Natural killer cells in hepatitis C virus infection: from innate immunity to adaptive immunity.

Natural killer (NK) cells are specialized lymphocytes that provide a first line of defense through their ability to kill pathogen-infected cells and transformed cells. The function of NK cells is regulated by a fine balance of inhibitory and activating signals, which are mediated by a diverse array of cell-surface receptors. We recently found that expression of the inhibitory receptor CD94/NKG2A is up-regulated on NK cells in patients with chronic hepatitis C. HLA-E, a ligand for NKG2A, was expressed in all human hepatoma cell lines tested as well as in nontransformed hepatocytes, but not in K562 cells, a classic NK-sensitive target. NK cells isolated from patients with chronic hepatitis C (HCV-NK) were less capable of killing hepatoma cells and of producing interferon-gamma in response to hepatoma cells than those from healthy donors, whereas there was no significant difference in NK responsiveness toward K562 cells. Of note is the finding that maturation and activation of monocyte-derived dendritic cells were negatively modulated in the presence of HCV-NK and hepatoma cells, which were restored by the addition of anti-NKG2A antibody during the coculture of HCV-NK and hepatoma cells. Research revealed that dendritic cells recognize danger signals from microorganisms by monitoring pathogen-associated molecular patterns via Toll-like receptors. Our findings have shed light on NK receptors as an important interface that transmits danger signals from abnormal cells to immune systems. Aberrant expression of CD94/NKG2A should have negative impact on innate resistance and subsequent adaptive immunity toward HCV-infected or transformed cells in chronic hepatitis C.

Cell Communication↗

PubMed2005

Enhanced perfusion defect clarity and inhomogeneity in smokers' lungs with deep-inspiratory breath-hold perfusion SPECT images.

PURPOSE: Deep-inspiratory breath-hold (DIBrH) Tc-99m-macroaggregated albumin (MAA) SPECT images were developed to accurately evaluate perfusion impairment in smokers' lungs. METHODS: DIBrH SPECT was performed in 28 smokers with or without low attenuation areas (LAA) on CT images, using a triple-headed SPECT system and a laser light respiratory tracking device. DIBrH SPECT images were reconstructed from every 4 degrees projection of five adequate 360 degrees projection data sets with almost the same respiratory dimension at 20 sec DIBrH. Perfusion defect clarity was assessed by the lesion (defect)-to-contralateral normal lung count ratios (L/N ratios). Perfusion inhomogeneity was assessed by the coefficient of variation (CV) values of pixel counts and correlated with the diffusing capacity of the lungs for carbon monoxide/alveolar volume (DLCO/VA) ratios. The results were compared with those on conventional images. RESULTS: Five DIBrH projection data sets with minimal dimension differences of 2.9+/-0.6 mm were obtained in all subjects. DIBrH images enhanced perfusion defects compared with conventional images, with significantly higher L/N ratios (P<0.0001), and detected a total of 109 (26.9%) additional detects (513 vs. 404), with excellent inter-observer agreement (kappa value of 0.816). CV values in the smokers' lungs on DIBrH images were also significantly higher compared with those on conventional images (0.31+/-0.10 vs. 0.19+/-0.06, P<0.0001). CV values in smokers on DIBrH images showed a significantly closer correlation with DLCO/VA ratios compared with conventional images (R = 0.872, P<0.0001 vs. R=0.499, P<0.01). CONCLUSION: By reducing adverse effect of respiratory motion, DIBrH SPECT images enhance perfusion defect clarity and inhomogeneity, and provide more accurate assessment of impaired perfusion in smokers' lungs compared with conventional images.

Artifacts↗

PubMed2005

Alteration in gene expression profile by full-length hepatitis B virus genome.

Persistent expression of hepatitis B virus (HBV) proteins is thought to be involved in virus-related hepatocarcinogenesis. Here, we compared the gene expression profile of cells persistently expressing the full-length HBV with that of negative control cells to comprehensively investigate virus-mediated changes in the gene expression of the host cells. RNA samples from both virus-expressing and negative control cells were used for the DNA array assay. DNA array assay and subsequent corroboration assays revealed that expression of 14 of 1,176 genes (1.2%) was altered in response to virus expression. The upregulated genes included CD44, high mobility group protein-I, thymosin beta-10 and 27-kD heat shock protein, while the downregulated genes included NM23-H1, all of which are thought to be associated with the development or progression of carcinoma in the liver or other organs. Furthermore, virus expression resulted in the decrease of two apoptosis-inducing molecules, caspase-3 and BAX, which may also contribute to carcinogenesis through prolonged survival of the host cell. Thus, expression of the virus genome caused carcinogenesis-related changes in host cell gene expression. HBV expression may change the host cell to a malignant phenotype through alterations in the expression levels of a set of genes.

Blotting, Western↗

PubMed2005

[Carcinoma of the urachus: a case report].

A 34-year-old married woman complaining of macrohematuria was admitted to our institute. Cystoscopy revealed a broad-stalk, nonpapillary tumor at the urinary bladder dome, and cold-punch biopsy proved it to be a mucus-producing adenocarcinoma. Abdominal managnetic resonance imaging demonstrated a tumor extending from the umbilicus to the bladder dome, and chest computed tomography (CT) demonstrated a small lung tumor with calcification. Examination of the upper gostroinstestinal tract, barium enema, and colon fiberscopy did not reveal abnormalities. We therefore diagnosed an urachal carcinoma with lung metastases. Total cystectomy, umbilical-urachal resection, hysterectomy, ileal neobladder, and partial resection of lung were performed, followed by partial resection of the left lung using thoracoscopy. About 6 months later, chest CT demonstrated multiple metastases in the right lung. After treatment with three courses of chemotherapy (paclitaxel and carboplatin), the right lung was partially resected. Serum CEA and CA19-9 levels were used to follow her disease, since both were elevated before the surgery and at the recurrence. Both indicators returned to their normal ranges after treatment. Such cases require careful observation using imaging modalities and tumor markers.

Adenocarcinoma, Mucinous↗

PubMed2005

[A young patient with invasive small cell carcinoma of the urinary bladder: a case report].

A 29-year-old woman with gross hematuria was referred to our hospital. Cystoscopy revealed a nonpapillary broad-based tumor on the right lateral wall of the urinary bladder, which a transurethral biopsy identified as transitional cell carcinoma (G2). CT and MRI suggested that the carcinoma invaded beyond the bladder wall. We performed a radical cystectomy with hysterectomy and the construction of an ileal neobladder. Pathological examination of the specimen indicated that it was small-cell undifferentiated carcinoma at the stage of pT2bpN0. For adjuvant chemotherapy, four cycles of CPT-11 and CDDP chemotherapy were performed, which is currently the usual chemotherapy for small-cell lung carcinoma in Japan. The patient is alive without any evidence of tumor recurrence at 12 months after surgery.

Adult↗

PubMed2005

[Salvage radiotherapy for pT3 prostate cancer with PSA failure after radical prostatectomy].

We assessed the effectiveness of salvage radiotherapy in 13 patients at pathologic stage T3 (pT3) with prostate specific antigen (PSA) failure after radical prostatectomy: 9 patients at pT3a and 4 patients at pT3b. Three-dimensional dynamic conformal radiotherapy was used for all patients in this study, and the median radiation dose was 57.7 Gy (range, 44-70 Gy) in daily amounts of 2 Gy. The median follow-up after salvage radiotherapy was 643 days (range, 193-1562 days). In 12 of the 13 patients, PSA levels decreased after salvage radiotherapy, but in 1 patient, the PSA level increased and hence the treatment was discontinued at 44 Gy. However, 10 patients exhibited a lasting PSA response. The 3-year biochemical progression-free rate was 74%, and no serious acute or late toxicity was observed during the follow-up. Salvage radiotherapy is likely to become one of the effective treatments for the patients at pT3 with PSA failure following radical prostatectomy.

Aged↗

PubMed2005

[Clinical analysis of bladder cancer patients undergoing radical cystectomy].

A retrospective clinicopathological study was performed on 96 bladder cancer patients who underwent radical cystectomy and pelvic lymphadenectomy at Aichi Cancer Center between April 1994 and July 2004. The follow-up period ranged from 4 to 109 months, with a mean of 39.1 months. The overall cancer-specific survival rates at 3, 5 and 7 years were 81.7%, 71.2% and 71.2%, respectively. The 5-year survival rate according to pathological stage was 97.3% for pT1 or lower, 66.4% for pT2, 47.6% for pT3, and 25.4% for pT4. Univariate analysis demonstrated the prognostic significance of pathological stage (p < 0.001), lymph node metastasis (p = 0.001), venous invasion (p < 0.001), lymphatic invasion (p = 0.010), preoperative creatinine clearance (p = 0.001) and preoperative hydronephrosis (p < 0.001). Multivariate analysis revealed strong independent correlations of venous invasion (p = 0.040) and preoperative hydronephrosis (p = 0.016) with prognosis.

Adult↗

PubMed2004

Negative regulation of NK cell activities by inhibitory receptor CD94/NKG2A leads to altered NK cell-induced modulation of dendritic cell functions in chronic hepatitis C virus infection.

NK cells are potent activators of dendritic cells (DCs), but it remains obscure how third-party cells affect the ability of NK cells to modulate DC functions. We show here that NK cells derived from healthy donors (N-NK), when cocultured with human liver epithelial cells, induced maturation as well as activation of DCs, such as increased migratory capacity as well as T cell stimulatory activity. In contrast, NK cells from chronic hepatitis C virus-infected donors (HCV-NK) were not capable of activating DCs under the same conditions. In comparison to N-NK, HCV-NK showed higher expression of CD94/NKG2A and produced IL-10 and TGFbeta when cultured with hepatic cells, most of which express HLA-E, a ligand for CD94/NKG2A. Blockade of NKG2A restored the ability of HCV-NK to activate DCs, which appeared to result from the reduced NK cell production of IL-10 and TGFbeta. The blockade also endowed HCV-NK with an ability to drive DCs to generate Th1-polarized CD4+ T cells. These findings show that NK cell modulation of DCs is regulated by third-party cells through NK receptor and its ligand interaction. Aberrant expression of NK receptors may have an impact on the magnitude and direction of DC activation of T cells under pathological conditions, such as chronic viral infection.

Antigens, CD↗

PubMed2004

Reduced numbers and impaired ability of myeloid and plasmacytoid dendritic cells to polarize T helper cells in chronic hepatitis C virus infection.

Hepatitis C virus (HCV) infection induces a wide range of chronic liver injuries. The mechanism by which HCV evades the immune surveillance system remains obscure. Blood dendritic cells (DCs) consist of myeloid and plasmacytoid subsets that play distinct roles in the regulation of antivirus immune responses; however, their roles in the pathogenesis of HCV infection are yet to be determined. We compared the numbers and functions of myeloid and plasmacytoid DCs between 43 patients with chronic hepatitis and 26 age-matched healthy volunteers. Absolute numbers of myeloid DCs, plasmacytoid DCs, and DC progenitors in the periphery were significantly lower in patients with chronic hepatitis than in healthy volunteers. Myeloid and plasmacytoid DCs from the patients had impaired abilities to stimulate allogeneic CD4 T cells and to produce interleukin (IL)-12 p70 and interferon- alpha , compared with those from healthy volunteers. After exposure to naive CD4 T cells, myeloid DCs from the patients were less able to drive the T helper type 1 response, whereas myeloid and plasmacytoid DCs from the patients primed more IL-10-producing cells than did those from healthy volunteers. In conclusion, in chronic HCV infection, both types of blood DCs are reduced and have an impaired ability to polarize T helper cells.

Cells, Cultured↗