Biomedical subjects

N Kanazawa

Publications and source records attributed to N Kanazawa.

At least 19 recordsLinked to original sources

PubMed2006

Expression of prostate-specific antigen and androgen receptor in extramammary Paget's disease and carcinoma.

Prostate-specific antigen (PSA) is a kallikrein-like serine proteinase (human kallikrein 3) produced by epithelial cells of both benign and malignant prostate tissue. In this study, PSA expression was histologically examined in tissue specimens from 34 patients with extramammary Paget's disease (EPD; 31 cases) and extramammary Paget's carcinoma (EPC; three cases), but no associated prostate carcinoma. Tumour cells positive for PSA were found in 17 of the 34 cases. Based on this finding, we examined serum PSA level in the three EPC cases. A high level of serum PSA was observed in one case of EPC, which was correlated with disease progression. Because some reports suggest that 50-80% cases of EPD/EPC express androgen receptor (AR), we also examined expression of AR. Immunohistological staining showed correlation of PSA and AR in expression. These results suggest that PSA and the androgen signalling pathway may be involved in the pathogenesis of EPD.

Aged↗

PubMed2006

Expressional screening of interferon-stimulated genes for antiviral activity against hepatitis C virus replication.

Type-I interferons (IFNs) and the interferon-stimulated genes (ISGs) play a major role in antivirus responses against hepatitis C virus (HCV) infection. In this study, we studied expression profiles of ISGs in cells supporting subgenomic HCV replication (Huh7/Rep), and screened their activities to suppress HCV replication. Real-time PCR analyses showed that the expression levels of 23 ISGs were significantly lower in Huh7/Rep than naive Huh7 cells due to transcriptional suppression of the interferon-stimulated response element (ISRE). Furthermore, the expression level of ISGs was also decreased in the cured Huh7 cells in which replicon had been eliminated (cHuh7), indicating adaptation of the cells to support HCV replication by downregulating ISGs. On the other hand, expression of HCV replicon was significantly suppressed by overexpression of several ISGs including PKR, MxA, IRF-9, GBP-1, IFI-6-16, IFI-27, 25OAS and IRF-1. Knock down of GBP-1, IFI-6-16 and IFI-27 by short hairpin RNA resulted in increase of HCV replication. Thus, we conclude that downregulation of ISG expression is required in the host cells supporting HCV replication and that several ISGs directly suppress HCV replication. The search for ISGs that regulate HCV replication may help to elucidate the cellular antiviral defence mechanisms against HCV infection.

Cell Line↗

PubMed2006

Site-specific mutation of the interferon sensitivity-determining region (ISDR) modulates hepatitis C virus replication.

The number of amino acid substitutions in the interferon sensitivity-determining region (ISDR) in the nonstructural 5A (NS5A) gene of hepatitis C virus (HCV) is closely associated with the interferon (IFN) response and viral load. Several HCV replicon-based studies have reported that ISDR sequences had an influence on viral replication in vitro. However, it is unclear as to how different ISDR sequences affect HCV replication. Various clinically observed ISDR sequences were introduced into HCV replicons and their contribution to viral replication was investigated using a colony formation assay and/or a transient replication assay. A mapping study of the ISDR was performed to identify the amino acid positions that critically affect replication. While no colonies were formed in the colony formation assay using HCV replicons with few mutations (0, 1 and 3) in the ISDR, numerous colonies (>200) appeared when using constructs with six mutations. Introduction of various distinct ISDR sequences with multiple mutations resulted in replication enhancement in transient assays. A mapping study identified several specific sites in the ISDR that critically affected replication, including codon 2209 which, in patients, was closely associated with a strong response to IFN. ISDR sequences associated with a clinical IFN response and viral load modulated the replication of HCV replicons, suggesting the importance of the ISDR sequence in HCV infection.

Amino Acid Sequence↗

PubMed2004

Differential gene-expression profiles associated with gastric adenoma.

Gastric adenomas may eventually progress to adenocarcinomas at varying rates. The purpose of the present study was to identify gene-expression profiles linked to the heterogeneous nature of gastric adenoma as compared to adenocarcinoma. Suppression subtractive hybridisation analysis was performed to extract relevant genes from two cases of low- and high-grade gastric adenomas. The identified genes were quantified by RT-PCR in 14 low-grade adenoma, nine high-grade adenoma and nine adenocarcinoma samples, followed by hierarchical clustering analysis to separate tumours into groups according to their gene-expression profiles. Nine genes previously implicated in carcinogenesis in a variety of organs, including three genes related to gastric adenocarcinoma, were identified. The overexpression of these genes in gastric adenoma has not been reported previously. The clustering analysis of these nine genes across 32 cases identified three groups, one of which consisted primarily of adenocarcinomas, whereas the other two groups consisted of adenomas. One group of adenomas, characterised by larger tumour size, exhibited gene-expression profiles of an intestinal cell lineage implicated in the pathogenesis of an intestinal-type gastric adenocarcinoma. Another adenoma group consisting of low-grade adenomas with smaller tumour size exhibited a unique expression profile. In conclusion, clustering analysis of expression profiles using a limited number of genes may serve as molecular markers for gastric adenoma with different biological properties. Although the prognostic values of these gene-expression profiles need to be evaluated in further follow-up study of adenoma cases, these findings add new insights to (a) our understanding of the pathogenesis of gastric tumours, (b) the development of specific tumour markers for clinical practice, and (c) the design of novel therapeutic targets.

Adenocarcinoma↗

PubMed2004

Introduction of NS5A mutations enables subgenomic HCV replicon derived from chimpanzee-infectious HC-J4 isolate to replicate efficiently in Huh-7 cells.

Hepatitis C virus (HCV) subgenomic replicon has been reported to replicate efficiently and continuously in human hepatoma Huh-7 cells. To extend the previous results to other isolated HCV clones, we constructed another HCV replicon from HC-J4, one of chimpanzee-infectious HCV clones. An HCV replicon derived from HC-J4 (RpJ4) consists of HCV-5' untranslated region, neomycin phosphotransferase gene, the encephalomyocarditis virus internal ribosomal entry site, HCV nonstructural region, NS3 to NS5B, and HCV-3' untranslated region. The adaptive mutations known to be required for HCV-Con1 replicon were introduced in RpJ4 replicon, aa.(amino acids number according to HC-J4) 2197 serine to proline, deletion of serine at aa.2201, and aa.2204 serine to isoleucine (RpJ4-S2197P, RpJ4-S22001del, and RpJ4-S2204I). RpJ4/ISDR mutant and RpJ4-S2201del/ISDR mutant were also constructed by introducing six amino acid mutations into the interferon sensitivity determining region (ISDR). After transfection into Huh-7 cells and G418 selection, RpJ4 and RpJ4/ISDR mutants did not produce any colony. In contrast, G418-resistant cells were transduced efficiently by RpJ4-S2197P, RpJ4-S2204I, RpJ4-S2201del and RpJ4-S2201del/ISDR mutant, with the RpJ4-S2201del/ISDR mutant being most efficient. Hence the HCV replicon derived from HC-J4 can replicate efficiently following the introduction of adaptive mutations into the upstream region of ISDR. Moreover, additional introduction of mutations into ISDR further enhanced its replication. These findings demonstrate that the genetic structure of the NS5A domain is critical in HCV replications.

Amino Acid Sequence↗

PubMed2001

Risk factors for distant recurrence of hepatocellular carcinoma in the liver after complete coagulation by microwave or radiofrequency ablation.

BACKGROUND: In patients with hepatocellular carcinoma (HCC), recurrences in the distant liver often are observed after curative treatment. Microwave coagulation therapy (MCT) and radiofrequency ablation (RFA) have been developed as less invasive alternatives than surgical resection for small HCCs. In the current study, risk factors for distant recurrence of HCC were analyzed in patients in whom complete coagulation was achieved. METHODS: Ninety-two patients with HCCs < 3 cm in greatest dimension were treated by MCT or RFA percutaneously or laparoscopically. Eighty-four patients in whom complete coagulation was achieved without recurrence in the same subsegment as the primary nodule were included in this study. Distant recurrences were observed in 22 patients. Fifteen possible risk factors for a distant recurrence were analyzed. RESULTS: When comparing the patients with a recurrence of HCC nodules in the remnant liver to those without recurrence, the authors observed a statistically significant difference only in serum alpha-fetoprotein. The distant recurrence-free survival was analyzed by the Kaplan-Meier method. A statistically significant difference was observed in hepatitis C virus (HCV) infection as an etiopathic agent of underlying liver diseases (P < 0.005) and in the number of the primary HCC nodules (P < 0.05, log-rank test). A multivariate stepwise Cox hazard model revealed that HCV infection and the number of primary HCC nodules were statistically independent risk factors. CONCLUSIONS: Patients who had more than two HCC nodules accompanied by HCV infection had a high incidence of recurrence of HCC in the remnant liver, even when coagulation by microwave or ablation by radiofrequency was complete.

Aged↗

PubMed2001

Unusual liver carcinomas with sarcomatous features: analysis of four cases.

We recently examined the clinicopathological and immunohistochemical features of four cases of primary hepatic carcinoma with sarcomatoid elements. Three of the four patients had associated ordinary hepatocellular carcinoma (HCC) and one had a sarcomatoid carcinoma with no apparent elements of HCC. The presenting symptoms were high fever and hypochondralgia in three patients, and right hypochondralgia without a high fever in one. The preoperative diagnoses were liver abscess in two patients, HCC in one, and cholangioma in one. Preoperative imaging showed necrotic change or abscess formation in the tumors. The sarcomatous elements showed a positive reaction to vimentin in three patients, but the ordinary HCC cells did not. Macroscopically, the tumors appeared as a single nodule with pericapsular growth. The prognoses of these patients were poor due to the early development of intrahepatic or distal metastases. We conclude that symptoms such as a high fever or hypochondralgia are characteristics of these tumors and that they may be histogenetically derived from a dedifferentiation of HCC, although no elements of HCC were found in one of our cases.

Aged↗

PubMed2001

Carcinoma arising in the pancreas 17 years after primary excision of a choledochal cysts: report of a case.

We report herein the case of a 42-year-old woman in whom a pancreatic carcinoma was found 17 years after excision of a choledochal cyst with Roux-en-Y hepaticojejunostomy. Although the incidence of biliary carcinoma associated with choledochal cyst is high, reports of cancer developing in the remaining intrapancreatic biliary tract or pancreas in patients who have previously undergone primary excision of a choledochal cyst are extremely rare. Long-term follow-up is recommended even for patients who have undergone excisional surgery for a choledochal cyst, in consideration of the possibility that cancer associated with the intrapancreatic biliary tract or pancreas may develop.

Adult↗

PubMed2001

Malignant sarcomatoid tumor of the liver: report of a case.

A 65-year-old man was referred to our hospital for treatment of a liver tumor. Abdominal ultrasonography (US) demonstrated a low echoic mass in the S2-S4 region of the liver, which was confirmed by abdominal computed tomography (CT). In the delayed phase of angio-CT, the inside of the mass was not enhanced. Abdominal angiography showed a hypovascular area in the liver. An extended left lobectomy was performed. Macroscopically, the tumor was 9.5 x 9.5 cm in size, and on cross section, it was white and clearly demarcated from the surrounding tissue. Microscopic observation of hematoxylin-eosin-stained specimens did not show any glandular or trabecular formation. Histologically, there was diffuse proliferation of atypical spindle cells that had hyperchromatic, short, spindle-shaped nuclei, and pale cytoplasm with poor intercellular adhesion. The nontumorous tissue was almost normal with no sign of cirrhosis. Immunohistochemical examination showed that the spindle cells were positive for vimentin and cytokeratins (AE1/AE3, CAM 5.2), but negative for all other markers. The final diagnosis was a sarcomatoid carcinoma, the origin of which was not able to be confirmed immunohistochemically. This case of a primary hepatic tumor composed of malignant cells with sarcomatous features is described, and the immunohistochemical findings are discussed.

Aged↗

PubMed2001

Diagnosis of Alexander disease in a Japanese patient by molecular genetic analysis.

Alexander disease is a leukodystrophy that is neuropathologically characterized by the presence of numerous Rosenthal fibers in astrocytes. Recently, mutations in the gene encoding glial fibrillary acidic protein (GFAP) were identified in patients with Alexander disease. We sequenced the GFAP gene of a Japanese girl who presented with typical symptoms of Alexander disease but in whom the diagnosis was not proven by histopathology. We identified a missense mutation, R239C, which is identical to the mutation previously reported to be most frequent. As was the case in previously described patients, our patient was also heterozygous for the de novo mutation. Interestingly, despite the fact that this is a de novo mutation, R239C was found to be common in different ethnic groups, implying that the site is a "hot spot" for mutagenesis. Molecular genetic analysis now makes the antemortem diagnosis of Alexander disease possible.

Brain↗

PubMed2001

Diagnosis of Japanese patients with HHH syndrome by molecular genetic analysis: a common mutation, R179X.

Patients with mitochondrial ornithine transporter deficiency (or HHH syndrome) present with various neurological symptoms, including mental retardation, spastic paraparesis with pyramidal signs, cerebellar ataxia, and episodic disturbance of consciousness or coma due to hyperammonemia. We previously described three novel mutations in the ORNT1 gene in Japanese patients with HHH syndrome. In this article, we report a new patient with HHH syndrome, a 52-year-old woman, who had the typical clinical features, except for an absence of mental retardation. When we screened this patient, as well as a previously described Japanese patient, for mutations in the ORNT1 gene, we found that both were homozygous for a nonsense mutation (R179X). Furthermore, reverse transcription (RT)-polymerase chain reaction (PCR) of fibroblast RNA from one patient showed exon 4 skipping, as had been observed in a previously reported patient with R179X. These results, together with the findings in our previous report, show that, in three of our five reported Japanese HHH patients (six of ten alleles), R179X is present, suggesting that this is a common mutation in Japanese patients with HHH syndrome.

Amino Acid Metabolism, Inborn Errors↗

PubMed2001

Extramedullary T lymphoid blast crisis representing an additional translocation, t(6;8)(q25;q22) in a patient with Philadelphia-positive chronic myelogenous leukemia after allogeneic bone marrow transplantation.

A patient with extramedullary crisis from chronic myelogenous leukemia after allogeneic bone marrow transplantation is reported. A pathological neck lymph node observed after transplantation revealed pre-T lymphoblastic phenotype, and the fluorescence in situ hybridization (FISH) analysis showed recipient type sex chromosomes and bcr/abl fusion gene. The cells represented an additional translocation, t(6;8)(q25;q22). No rearrangements of the T-cell receptor (TCR) beta, gamma or delta chain genes were observed. The absence of TCR rearrangement indicated the clonogenic involvement of pluripotent hematopoietic stem cells by Philadelphia chromosome. Bone marrow specimens at that time showed donor type sex chromosomes and no bcr/abl-positive cells by FISH.

Blast Crisis↗

PubMed2001

A potent antiviral effect on hepatitis C viral dynamics in serum and peripheral blood mononuclear cells during combination therapy with high-dose daily interferon alfa plus ribavirin and intravenous twice-daily treatment with interferon beta.

Hepatitis C virus (HCV) is known to infect and replicate within peripheral blood mononuclear cells (PBMC), thereby enabling the direct evaluation of antiviral mechanisms by analyzing HCV dynamics in PBMC. To address potential molecular differences associated with distinct antiviral regimens, we studied HCV dynamics in both serum and PBMC in 44 patients with HCV genotype 1b and high viral load who were randomly assigned to the following 4 different treatment groups: 1) combination therapy with 6 MU daily of interferon alfa 2b (IFN-alpha2b) plus 800 mg of ribavirin; 2) monotherapy with 6 MU daily of IFN-alpha2b; 3) monotherapy with twice-daily intravenous administration with 3MU of IFN-beta; and 4) monotherapy with daily intravenous administration with 6 MU of IFN-beta. HCV-RNA levels were measured serially using highly sensitive real-time detection polymerase chain reaction (PCR). HCV dynamics in both the serum and PBMC showed a "biphasic" pattern. The exponential decay slopes of the second phase were significantly higher in the combination or twice-daily dosing regimen groups compared with groups 2 or 4 (0.10 +/- 0.08 vs. 0.02 +/- 0.09 or 0.16 +/- 0.09 vs. 0.02 +/- 0.04 day(-1); P <.05 or P <.0005, respectively). Moreover, the viral half-lives in the second phase were significantly shorter in these groups (73.2 +/- 42.5 vs. 240.1 +/- 120.7 or 56.0 +/- 44.6 vs. 361.6 +/- 293.5 hours; P <.05 or P <.05, respectively). Additionally, the slope of HCV decline in PBMC tended to be higher in the combination regimens, as compared with monotherapy. Taken together, our data on HCV dynamics provide molecular insight into utilization of combination or twice-daily dosing regimens to increase rates of sustained viral eradication of HCV.

Adult↗

PubMed2001

p53 deficiency alters the yield and spectrum of radiation-induced lacZ mutants in the brain of transgenic mice.

Exposure to heavy particle radiation in the galacto-cosmic environment poses a significant risk in space exploration and the evaluation of radiation-induced genetic damage in tissues, especially in the central nervous system, is an important consideration in long-term manned space missions. We used a plasmid-based transgenic mouse model system, with the pUR288 lacZ transgene integrated in the genome of every cell of C57Bl/6(lacZ) mice, to evaluate the genetic damage induced by iron particle radiation. In order to examine the importance of genetic background on the radiation sensitivity of individuals, we cross-bred p53 wild-type lacZ transgenic mice with p53 nullizygous mice, producing lacZ transgenic mice that were either hemizygous or nullizygous for the p53 tumor suppressor gene. Animals were exposed to an acute dose of 1 Gy of iron particles and the lacZ mutation frequency (MF) in the brain was measured at time intervals from 1 to 16 weeks post-irradiation. Our results suggest that iron particles induced an increase in lacZ MF (2.4-fold increase in p53+/+ mice, 1.3-fold increase in p53+/- mice and 2.1-fold increase in p53-/- mice) and that this induction is both temporally regulated and p53 genotype dependent. Characterization of mutants based on their restriction patterns showed that the majority of the mutants arising spontaneously are derived from point mutations or small deletions in all three genotypes. Radiation induced alterations in the spectrum of deletion mutants and reorganization of the genome, as evidenced by the selection of mutants containing mouse genomic DNA. These observations are unique in that mutations in brain tissue after particle radiation exposure have never before been reported owing to technical limitations in most other mutation assays.

Animals↗

PubMed2001

Treatments of non-parasitic giant hepatic cysts.

This retrospective study presents the results of surgical treatments for large cyst of the liver over 10 cm in diameter in 9 patients diagnosed and treated at Kurume University Hospital. There were 8 women and 1 man, with an average age of 71.6 years. Although the chief complaints were abdominal pain or fullness, 1 had obstructive jaundice due to biliary compression by a large cyst. Cyst size ranged from 10 cm to 27 cm. There are several treatment modalities for giant hepatic cyst, such as cyst resection, unroofing, and sclerotherapy after cyst drainage. Operative procedures in the patients reported here were surgical resection of the liver cyst in 3 patients, unroofing with ethanol sclerotherapy in 1 patient and laparoscopic treatment in 2 patients. Sclerotherapy after percutaneous transhepatic cyst drainage was performed in 3 patients because their general condition was poor. There were no postoperative complications among these patients. Costs varied among the patients and depended mainly on the method of treatment and period of hospital stay. We discuss operative procedures and costs of treatment of each patient and review the literature.

Aged↗

PubMed2001

Xanthogranulomatous cholecystitis.

Seven cases of xanthogranulomatous cholecystitis are presented, and their clinicopathological appearance is described. Three men and 4 women with xanthogranulomatous cholecystitis, aged 53-72 years old, were reviewed. Five patients had had previous attacks of acute cholecystitis lasting from 3 weeks to 6 months. Abdominal ultrasonography was performed in all patients, and computed tomography in 5 patients. Cholelithiasis and sludge were present in all patients. The gallbladder wall was thickened in all patients. On computed tomography, one patient showed no abnormal finding, and 4 patients had abnormal findings such as increased wall thickness and irregularity, and pericholecystic abnormalities. A diagnosis of gallbladder carcinoma was made preoperatively in 1 patient. During laparotomy, the gallbladders in all patients showed signs of chronic cholecystitis, and cholecystectomies were performed. Histological findings showed xanthogranulomatous cholecystitis, and 4 patients had stones in the gallbladder wall. Despite the characteristic histologic appearance of xanthogranulomatous cholecystitis, radiologic findings are nonspecific, varying from signs observed in other forms of cholecystitis to the appearance of a gallbladder neoplasm. We report here 7 cases of xanthogranulomatous cholecystitis and review the literature.

Aged↗

PubMed2001

[Molecular genetic studies of mitochondrial ornithine transporter deficiency (HHH syndrome)].

Mitochondrial ornithine transporter deficiency has been called HHH syndrome, because this disorder is characterized by three biochemical abnormalities; hyperornithinemia, hyperammonemia, and homocitrullinuria, and presents with various neurological symptoms; mental retardation, spastic paraparesis with pyramidal signs, cerebellar ataxia and episodic disturbance of consciousness or coma due to hyperammonemia. We identified four mutations in the mitochondrial ornithine transporter gene (ORNT1) of Japanese patients with HHH syndrome. These include a nonsense mutation (R179X), associated with exon skipping, missense mutations (G27E, P126R), and an insertion of AAC between codons 228 and 229, leading to an insertion of amino acid Asn. Especially, R179X was detected 4 of 7 Japanese patients (8 of 14 alleles), implying that this is a common mutation in Japanese population.

Amino Acid Transport Systems, Basic↗

PubMed2001

HZE particle radiation induces tissue-specific and p53-dependent mutagenesis in transgenic animals.

Transgenic animals, with the integrated target gene, provide a unique approach for measuring and characterizing mutations in any tissue of the animal. We are using the plasmid-based lacZ transgenic mice with different p53 genetic background to examine radiation-induced genetic damage resulting from exposure to heavy particle radiation. We measured lacZ mutation frequencies (MF) in the brain and spleen tissues at various times after exposing animals to an acute dose of 1 Gy of 1GeV/amu iron particles. MF in the spleen of p53+/+ animals increased up to 2.6-fold above spontaneous levels at 8 weeks post irradiation. In contrast, brain MF from the same animals increased 1.7-fold above controls in the same period. In the p53-/- animals, brain MF increased to 2.2-fold above spontaneous levels at 1 week after treatment, but returned to control levels thereafter. Radiation also induced alterations in the spectrum of mutants in both tissues, accompanied by changes in the frequency of mutants with deletions extending past the transgene into mouse genomic DNA. Our results indicate that the accumulation of transgene MF after radiation exposure is dependant on the tissue examined as well as the p53 genetic background of the animals.

Animals↗