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Biomedical subjects

Junji Kato

Publications and source records attributed to Junji Kato.

At least 37 records · Page 2Linked to original sources
PubMed2005

Iron accumulation in alcoholic liver diseases.

Increased hepatic iron is one of the important key factors which contribute alcohol toxicity of liver due to the production of reactive oxygen species. In patients with alcoholic liver diseases (ALD), liver iron is increased and the resulted lipid metabolite 4-hydroxynonenal-protein adduct was also increased. In general, iron is deposited in both parenchymal cells and and Kupffer cells in ALD. However, in patients with mild ALD, the parenchymal iron deposition is dominant rather than reticuloendothelial iron deposition, while the latter iron deposition is domimant in severe ALD, possibly due to endotoxemia and overproduction of inflammatory cytokines. We speculated that a parenchymal iron deposition in mild ALD is an important factor to trigger hepatocytes injury by ethanol, and the possible cause of parencynal iron deposition may be an increase of cellular iron uptake via serum transferrin in hepatocytes after ethanol exposure. By immuno-histochemical study of biopsied liver samples, the expression of transferrin receptor 1 (TfR1), which mediates cellular iron uptake by serum transferrin was increased. This increase of TfR1 by ethanol is confirmed by in vitro experiment using HepG2 cells and primary rat hepatocytes culture. Fe-labeled transferrin incorporation (but not transferrin non-bound iron (NTBI)) into the cells is also increased, suggesting that the increased TfR1 is functional. The increase of TfR1 expression is partially due to the increased activity of iron regulatory protein (IRP) by oxidative stress of ethanol metabolism. Thus, the post-transcriptional regulation of iron uptake by ethanol is involved in the hepatocyte iron accumulation. Another possibility is an increase of intestinal iron absorption. Our recent finding regarding the increase of pro-hepcidin serum in alcoholic patients with high serum ferritin support this assumption.

Aldehydes↗
PubMed2005

Expansion of CD34+ cells on telomerized human stromal cells without losing erythroid-differentiation potential in a serum-free condition.

Erythropoiesis progresses from stem cell expansion on stromal cells through the formation of an erythroblastic island. Our aim was to assess the feasibility of using human stromal cells for erythroid production and differentiation. When cord blood CD34+ cells were cocultured with telomerized human stromal cells (hTERT-stromal cells) for 2 weeks, the CD34+ cells and burst-forming units-erythroid (BFU-E) significantly expanded, and a few hematopoietic cells transmigrated below the stromal layer. When nonadherent hematopoietic progenitor cells that had expanded above the hTERT-stromal cells (group B) were collected and subjected to our erythroid-differentiation protocol, they differentiated into erythroblasts with a slight hemoglobin synthesis. When the few hematopoietic cells that had transmigrated below the stromal layer were expanded for an additional 2 to 6 weeks, they exhibited a cobblestone-like appearance, and a large amount of BFU-E clambered weekly from the underside of the stromal layer to above the stromal layer (group C). When the hematopoietic progenitor cells in group C were subjected to the erythroid-differentiation protocol, large numbers of mature erythroblasts (more than 300,000 times the initial CD34+ cell number) were produced. Our hTERT-stromal expansion protocol may contribute to the construction of a system for large-scale, long-term production of erythroid cells.

Antigens, CD34↗
PubMed2005

A patient with TP53 germline mutation developed Bowen's disease and myelodysplastic syndrome with myelofibrosis after chemotherapy against ovarian cancer.

Here we report a case of myelodysplastic syndrome (MDS) with myelofibrosis associated with Bowen's disease. A female patient had undergone an operation and chemotherapy for ovarian cancer when she was 65 years old, and she developed MDS at the age of 70 years old. PCR-single strand conformation polymorphism (SSCP) analysis of peripheral blood mononuclear cells, a Bowen's disease lesion, and normal skin showed an abnormal peak in TP53 exon5. Direct sequencing revealed that they all had missense mutation in codon 175 (G to A) of arginine switched to histidine, suggesting a germline mutation of TP53. It was speculated that p53 function was lost by TP53 germline mutation with the loss of a wild type allele induced by the chemotherapy against ovarian cancer, leading to the development of MDS. No therapeutic effects of low dose melphalan or cyclosporine A on MDS were observed, however one month of 30 mg/day prednisolone administration induced a hematological response.

Aged↗
PubMed2005

[Essential thrombocythemia associated with incomplete type intestinal Behçet disease during hydroxyurea treatment].

A 77-year-old man was diagnosed as having essential thrombocythemia in 1992. Treatment with hydroxyurea was started in 1997, which stabilized the platelet count. The patient then suffered from pharyngalgia and rhinitis with a high fever, immediately after which he developed tarry stools and anemia and was admitted to our hospital. The physical examination revealed splenomegaly, oral aphthous ulcers, genital ulcers and skin lesions on the lower limbs. His hematological and biochemical tests revealed anemia and increased level of C-reactive protein. He also had an HLA-B51 phenotype. The findings of gastro-intestinal and colon fiberoscopy showed a duodenal ulcer and multiple ulcers on ascending colon. He was thus diagnosed as having intestinal tract-type Behçet disease. After withdrawal of the hydroxyurea administration, the intestinal ulcers, oral aphthous ulcers and genital ulcers improved.

Aged↗
PubMed2004

Plasma glutathione S-Transferase P1-1 as a prognostic factor in patients with advanced non-Hodgkin's lymphoma (stages III and IV).

PURPOSE: This study aims to investigate whether the plasma level of glutathione S-transferase P1-1 (GSTP1-1), which is a phase II detoxifying enzyme known to be a resistance factor for anticancer drugs, could be a prognostic factor of de novo non-Hodgkin lymphoma (NHL) in clinical stages (CSs) III and IV. EXPERIMENTAL DESIGN: Study population consisted of 80 NHL patients with no prior treatment: 12 patients were at CS I, 14 at CS II, 25 at CS III, and 29 at CS IV. All 54 patients at CS III or CS IV were treated with cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP). Plasma GSTP1-1 concentration was measured by ELISA. We stained lymph node tissues for GSTP1-1 using anti-GSTP1-1 monoclonal antibody 5F and quantitatively assessed the intensity of immunostaining by using the KS-400 image analyzing system. RESULTS: There was a significant stepwise increment of plasma GSTP1-1 concentration from CS I to CS IV (P < 0.05). Of the 54 patients with CS III or IV treated with CHOP, 28 (52%) had elevated plasma GSTP1-1 levels. Plasma GSTP1-1 concentration tended to correlate with the intensity of GSTP1-1 expression in lymphoma tissues as assessed by immunostaining (P = 0.07). The CR rates in patients at CS III and CS IV treated by CHOP, 55.2% (14 of 26) and 16.0% (5 of 28) for the low and high plasma GSTP1-1 groups, respectively, were significantly different (P < 0.01). For these two groups, the median survival times were 64 and 25 months, respectively (P < 0.01), and the median times to progression were 58 and 12 months, respectively (P < 0.01). There was no significant correlation between plasma GSTP1-1 concentrations and other NHL prognostic indicators in these patients as determined by univariate and multivariate analyses. CONCLUSION: These results showed that plasma GSTP1-1 is a useful prognostic factor for CS III and IV advanced NHL. Thus, it may be a promising strategy to treat NHL concomitantly with anticancer drugs and GSTP1-1-specific inhibitors.

Adult↗
PubMed2004

Fas-mediated apoptosome formation is dependent on reactive oxygen species derived from mitochondrial permeability transition in Jurkat cells.

Generation of reactive oxygen species (ROS) and activation of caspase cascade are both indispensable in Fas-mediated apoptotic signaling. Although ROS was presumed to affect the activity of the caspase cascade on the basis of findings that antioxidants inhibited the activation of caspases and that the stimulation of ROS by itself activated caspases, the mechanism by which these cellular events are integrated in Fas signaling is presently unclear. In this study, using human T cell leukemia Jurkat cells as well as an in vitro reconstitution system, we demonstrate that ROS are required for the formation of apoptosome. We first showed that ROS derived from mitochondrial permeability transition positively regulated the apoptotic events downstream of mitochondrial permeability transition. Then, we revealed that apoptosome formation in Fas-stimulated Jurkat cells was clearly inhibited by N-acetyl-L-cysteine and manganese superoxide dismutase by using both the immunoprecipitation and size-exclusion chromatography methods. To confirm these in vivo findings, we next used an in vitro reconstitution system in which in vitro-translated apoptotic protease-activating factor 1 (Apaf-1), procaspase-9, and cytochrome c purified from human placenta were activated by dATP to form apoptosome; the formation of apoptosome was markedly inhibited by reducing reagents such as DTT or reduced glutathione (GSH), whereas hydrogen peroxide prevented this inhibition. We also found that apoptosome formation was substantially impaired by GSH-pretreated Apaf-1, but not GSH-pretreated procaspase-9 or GSH-pretreated cytochrome c. Collectively, these results suggest that ROS plays an essential role in apoptosome formation by oxidizing Apaf-1 and the subsequent activation of caspase-9 and -3.

Apoptosis↗
PubMed2004

Indian hedgehog gene transfer augments hematopoietic support of human stromal cells including NOD/SCID-beta2m-/- repopulating cells.

Hematopoietic stem cells (HSCs) are a subset of bone marrow cells that are capable of self-renewal and of giving rise to all types of blood cells. However, the mechanisms involved in controlling the number and abilities of HSCs remain largely unknown. The Indian hedgehog (Ihh) signal has an essential role in inducing hematopoietic tissue during embryogenesis. We investigated the roles of the Ihh in coculture with CD34+ cells and human stromal cells. Ihh mRNA was expressed in primary and telomerized human (hTERT) stromal cells, and its receptor molecules were detected in CD34+ cells. Ihh gene transfer into hTERT stromal cells enhanced their hematopoietic supporting potential, which was elevated compared with control stromal cells, as indicated by the colony-forming units in culture (CFU-Cs) (26-fold +/- 2-fold versus 59-fold +/- 3-fold of the initial cell number; mixed colony-forming units [CFU-Mix's], 63-fold +/- 37-fold versus 349-fold +/- 116-fold). Engraftments of nonobese diabetic/severe combined immunodeficiency-beta2m-/- (NOD/SCID-beta2-/-) repopulating cells (RCs) expanded on Ihh stromal cells were significantly higher compared with control coculture results, and engraftment was neutralized by addition of an antihedgehog antibody. Limiting dilution analysis indicated that NOD/SCID-beta2m-/- RCs proliferated efficiently on Ihh stromal cells, compared with control stromal cells. These results indicate that Ihh gene transfer could enhance the primitive hematopoietic support ability of human stromal cells.

Animals↗
PubMed2004

Interleukin-11 as an osteoprotegerin-inducing factor in culture medium of blastic cells from a patient with acute megakaryocytic leukemia complicated with osteosclerosis.

We came across a rare case of acute megakaryocytic leukemia, the clinical course of which was relatively chronic and nonaggressive. This case was complicated with generalized severe osteosclerosis (OS). The medium in which blastic cells from the patient were cultured showed a strong activity to enhance the expression of an osteosclerotic cytokine, osteoprotegerin (OPG), as revealed by real-time quantitative RT-PCR and Western blot analysis. The OPG-inducing activity of the culture medium was neutralized by the anti-interleukin-11 (IL-11) antibody. These results indicate that IL-11 produced by the blasts was a causative factor of the OS observed in this patient.

Adult↗
PubMed2004

Chemoprevention of colorectal cancer.

Colorectal cancer is a disease with a high mortality rate and it has been increasing in prevalence worldwide. Chemoprevention, as well as primary and secondary prevention, for colorectal cancer have attracted much attention. Many chemopreventive trials have been performed, and several agents, including nonsteroidal antiinflammatory drugs, such as aspirin and sulindac, cyclooxygenase-2 selective inhibitors, such as celecoxib, vitamin D, folate, and calcium, have been shown to have some effect. In these chemopreventive trials, the targeted lesions used for evaluation were mainly polyps. However, the chemopreventive effects of some agents on polyps may require several years to evaluate. Further, larger polyps may not be susceptible to chemopreventive agents. Aberrant crypt foci (ACF) are tiny lesions at the earliest stage of colorectal carcinogenesis, which consist of large, thick crypts identified by dense, methylene blue staining. We succeeded in identifying human ACF in situ using magnifying endoscopy and found that the number of ACF, particularly dysplastic ACF, increased significantly from normal subjects to adenoma patients and then to cancer patients. We also found that the number, size, and dysplastic features of ACF are significantly correlated with the number of adenomas in adenoma patients. Thus, it was surmised that ACF are precursor lesions of the adenoma-carcinoma sequence in humans and that ACF may be the most appropriate lesions as targets for chemoprevention. We have shown that the number of ACF was significantly reduced in patients treated with sulindac. We are currently proceeding with a randomized, double-blind, chemopreventive trial targeting ACF.

Animals↗
PubMed2004

A significant reduction in serum alanine aminotransferase levels after 3-month iron reduction therapy for chronic hepatitis C: a multicenter, prospective, randomized, controlled trial in Japan.

BACKGROUND: Increasing evidence indicates that iron cytotoxicity plays an important role in the pathogenesis of chronic hepatitis C (CHC). However, the biochemical effects of iron reduction therapy on CHC remain to be confirmed in a controlled study. This study aimed to test whether iron removal by repeated phlebotomy improves serum alanine aminotransferase (ALT) levels in patients with CHC. METHODS: Patients were randomly assigned to an iron reduction therapy or control group. The patients in the treatment group received 3-month iron reduction therapy by biweekly phlebotomy, while the patients in the control group were followed up for 3 months with regular blood tests alone. RESULTS: Thirty-three patients completed the 3-month treatment, while 29 patients received the complete follow-up. The serum ALT levels were reduced from 118 +/- 79 to 73 +/- 39 IU/L in the treatment group, but did not change in the control group (106 +/- 45 versus 107 +/- 48 IU/L). Posttreatment enzyme activity was decreased significantly from the baseline. Furthermore, it was significantly lower than the 3-month control level. Although 5 patients withdrew from the study, none was affected by any side effects of repeated phlebotomy that required them to discontinue the treatment. CONCLUSIONS: This short-term controlled trial demonstrated the biochemical efficacy and safety of iron reduction therapy for patients with CHC.

Adult↗
PubMed2004

Wnt3 modulates the characteristics and cobblestone area-supporting activity of human stromal cells.

OBJECTIVE: Our objective was to investigate the expression and significance of Wnt proteins in adult human hematopoietic-supporting stromal cells. METHODS: Degenerate reverse transcription-polymerase chain reaction was performed to screen telomerized human stromal cells (hTERT-stromal cells) and multipotent mesenchymal cells (hTERT-MSCs) for expression of Wnt genes. We studied the actions of Wnt proteins by overexpressing them in stromal cells and MSCs by retrovirus-mediated gene transfer. RESULTS: The hTERT-stromal and primary stromal cells expressed Wnt5A, while hTERT-MSCs and primary MSCs expressed Wnt3 and Wnt5A. Gene transfer of Wnt5A slightly reduced the growth rate of hTERT-stromal cells, but did not affect their morphology. In contrast, gene transfer of Wnt3 into both hTERT-stromal cells and hTERT-MSCs enhanced Wnt-betacatenin signaling, and caused remarkable morphological changes and growth retardation. Upon 2-week co-culture, expansion of clonogenic cells on Wnt5A-stromal cells was superior to that on control stromal cells. However, expansion of CD34+ cells on Wnt3-stromal cells did not differ from that on control stromal cells. Moreover, there was a drastic reduction in the formation of cobblestone area (CA) underneath Wnt3-stromal cells compared with that underneath control stromal cells. CONCLUSION: These results suggest that Wnt3 plays an important role in regulating characteristics and CA support activity of stromal cells.

Antigens, CD34↗
PubMed2004

Prolonged survival of mice with multiple liver metastases of human colon cancer by intravenous administration of replicable E1B-55K-deleted adenovirus with E1A expressed by CEA promoter.

Liver is the most preferential site for metastasis of colon cancer. We, in the present study, constructed a self-replicable adenovirus in which E1A is driven by a CEA promoter and E1B-55K is deleted from the E1B region (AdCEAp/Rep) and examined its effects on multiple metastases of a human colon cancer cell in a mouse xenograft model. We first showed effective replication of the virus in various CEA-producing human colon cancer cells (M7609, HT-29) and subsequent lysis of the infected cells in vitro. We then demonstrated that a single intratumoral injection of the virus (1 x 10(8) PFU/100 microl) induced a complete regression of subcutaneous tumors (M7609) inoculated into nude mice. Further, we demonstrated that systemic administration of the virus (1 x 10(8) PFU/100 microl) through the tail vein to nude mice, which 1 week prior had been inoculated with tumor cells (colon carcinoma cell line HT-29) via the spleen and showed apparent multiple metastases in the liver, effectively suppressed the metastasis formation. The mean survival time of the treated mice was significantly longer than that of the controls. Thus, the systemic administration of AdCEAp/Rep was considered to be effective on multiple liver metastases of CEA-positive colon cancer in a xenograft model.

Adenoviridae↗
PubMed2004

Decrease of Smad4 gene expression in patients with essential thrombocythaemia may cause an escape from suppression of megakaryopoiesis by transforming growth factor-beta1.

Essential thrombocythaemia (ET) is characterized by the abnormal and sustained proliferation of megakaryocytes. The mechanism for this lineage-specific expansion in ET, remains unclear. We have previously reported that transforming growth factor-beta1 (TGF-beta1) is involved in negative feedback regulation of megakaryopoiesis in both healthy volunteers (HV) and patients with idiopathic thrombocytopenic purpura (ITP). The present study found that megakaryocyte colony-forming units (CFU-MK) of ET patients were less sensitive to TGF-beta1 than those of HV. The expression of Smad4 (Sma- and Mad-related protein-4) in CFU-MK of ET patients was reduced in comparison with that of HV. Finally, to confirm that the impaired TGF-beta1 sensitivity was caused by reduced expression of Smad4, we examined Smad4-transfected CFU-MK from ET patients in the presence of TGF-beta1, and verified that the transfectants were indeed as susceptible as CFU-MK from HV to TGF-beta1. Thus it was surmised that one of the mechanisms for impaired sensitivity of CFU-MK to TGF-beta1 is the reduced expression of Smad4.

Adult↗
PubMed2004

Glutathione-S-transferase P1-1 protects aberrant crypt foci from apoptosis induced by deoxycholic acid.

BACKGROUND & AIMS: Aberrant crypt foci, precursors of colonic adenoma, are frequently positive for glutathione-S-transferase P1-1. Because deoxycholic acid is an apoptosis-inducing xenobiotic in the colon, we examined the possibility that aberrant crypt foci, through the cytoprotecting function of glutathione-S-transferase P1-1, resist deoxycholic acid-induced apoptosis, thereby surviving to become adenomas and subsequently cancer. METHODS: Glutathione-S-transferase P1-1 or cyclooxygenase-2 expression and the percentage of apoptotic cells in aberrant crypt foci were examined by immunohistochemistry and by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling, respectively. Glutathione-S-transferase P1-1 was transfected into colon cancer cells (M7609) and human lung fibroblasts, and deoxycholic acid-induced apoptosis was evaluated by a dye-uptake assay and flow cytometry. Binding of deoxycholic acid to glutathione-S-transferase P1-1 was analyzed by circular dichroism and immunoprecipitation. Caspase activities were determined by colorimetric protease assay, and sulindac binding to glutathione-S-transferase P1-1 was determined by inhibition assay of glutathione-S-transferase P1-1 activity. RESULTS: Aberrant crypt foci showed positive immunostaining for glutathione-S-transferase P1-1 but negative staining for cyclooxygenase-2. The percentage of apoptotic cells in aberrant crypt foci was significantly lower than in healthy epithelium, and the difference became more apparent with deoxycholic acid treatment. The impaired sensitivity of aberrant crypt foci to deoxycholic acid was restored by the glutathione-S-transferase P1-1-specific inhibitor gamma-glutamyl-S-(benzyl)cysteinyl-R-phenylglycine diethylester. By transfection of glutathione-S-transferase P1-1, M7609 cells became more resistant to deoxycholic acid-induced apoptosis than mock transfectants. Direct binding of glutathione-S-transferase P1-1 to deoxycholic acid was proven by circular dichroism and by immunoprecipitation. The aberrant crypt foci in adenoma patients treated with sulindac, which was shown to bind to glutathione-S-transferase P1-1, underwent apoptosis in 4 days and mostly regressed in 2-3 months. CONCLUSIONS: Glutathione-S-transferase P1-1 protects aberrant crypt foci from deoxycholic acid-induced apoptosis and may play a pivotal role in early colon carcinogenesis.

Adenoma↗
PubMed2004

A case of Gardner syndrome with a mutation at codon 1556 of APC: a suggested case of genotype-phenotype correlation in dental abnormality.

A 25-year-old man with suspected Gardner syndrome was introduced to our hospital by a dentist who, during examination of the patient, had found dental dysplasias and multiple osteomas of the jaw. Radiographs, endoscopy and biopsies revealed adenomatous polyposis of the colon. Genetic analysis of peripheral lymphocytes revealed a one-base deletion at codon 1556 in exon 15 of APC, which caused a frame shift and a premature stop at codon 1564. The pedigree analysis demonstrated five patients in his family who presented with dental abnormality and osteomas in addition to adenomatous polyposis of the colon. Although the relationship between the location of APC mutations and dental abnormalities remains controversial, this case supports the hypothesis that a mutation at around codon 1556 of APC is closely associated with dental abnormality and osteomas.

Adult↗