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N Sato

Publications and source records attributed to N Sato.

At least 271 records · Page 15Linked to original sources
PubMed2000

Stromal cell-dependent ex vivo expansion of human cord blood progenitors and augmentation of transplantable stem cell activity.

In vitro maintenance and expansion of human hematopoietic stem cells is crucial for many clinical applications. Thrombopoietin (TPO) and flt3/flk2 ligand (FL) have been suggested to support the proliferation of primitive hematopoietic progenitors and the expansion of transplantable stem cells in culture. In this study, we examined the synergistic effects of the murine stromal cell line MS-5 and a combination of the two cytokines, TPO and FL, on the ex vivo expansion of human cord blood primitive progenitors and transplantable stem cells. A monolayer of MS-5 cells with TPO/FL synergistically supported a more than 600-fold expansion of human cord blood CD34+ cells and CD34+CD38- cells in 2 weeks of culture. Colony-forming unit in culture (CFU-C) and 5-week and 8-week cobblestone area-forming cells (CAFC) were also expanded approximately 300-, 4- and 13-fold, respectively. When MS-5 cells were physically separated from progenitors by a Transwell filter, the synergy was reduced to a quarter of the control, suggesting that direct cell-cell contact between MS-5 cells and progenitors is required for maximum expansion. The severe-combined immunodeficient (scid) mouse-reconstituting cell (SRC) assay demonstrated the slight augmentation of transplantable stem cell activity in culture. These results indicated that MS-5 cells provide a milieu that stimulates the proliferation of primitive progenitors including transplantable stem cells.

Animals↗
PubMed2000

Selective localization of Bcl-2 to the inner mitochondrial and smooth endoplasmic reticulum membranes in mammalian cells.

Bcl-2, an anti-apoptotic protein, is believed to be localized in the outer mitochondrial membrane, endoplasmic reticulum, and nuclear envelope. However, Bcl-2 has also been suggested as playing a role in the maintenance of mitochondrial membrane potential, indicating its possible association with the inner mitochondrial membrane. We therefore further examined the exact localization of Bcl-2 in mitochondria purified from wild-type and bcl-2-transfected PC12 cells and pre- and postnatal rat brains. Double immunostaining demonstrated that Bcl-2 was co-localized with subunit beta of F1F0ATPase in the inner mitochondrial membrane. Biochemical analysis of isolated mitochondria using digitonin and trypsin suggests an association of Bcl-2 with the inner mitochondrial membrane. More interestingly, the majority of Bcl-2 disappeared from the inner membrane of mitochondria when cultured under serum deprivation. These results suggest that Bcl-2 acts as an anti-apoptotic regulator by localizing mainly to the inner mitochondrial and smooth ER membranes.

Animals↗
PubMed2000

Stromal cell-independent differentiation of human cord blood CD34+CD38- lymphohematopoietic progenitors toward B cell lineage.

To study the cytokine regulation of early stages of human B-lymphopoiesis, we developed a stroma-free two-step culture system. Single human cord blood CD34+CD38- cells were individually cultured by micromanipulation with interleukin (IL)-3, stem cell factor (SCF), fIt3 ligand (FL), IL-6 and granulocyte colony-stimulating factor (G-CSF). About 10% of the cells formed primary colonies, which were individually tested for myeloid and B-lymphoid potentials by reculturing aliquots of the primary colony cells into secondary myeloid and B-lymphoid cultures. One third of the primary colonies proved capable of differentiation into CD19+IgM+ cells, as well as into myeloid lineage cells. RT-PCR analyses revealed that some cells in the primary culture had already matured to express B cell-specific transcripts. Thus, the combination of IL-3, SCF, FL, IL-6 and G-CSF supported the differentiation of CD34+CD38- lymphohematopoietic progenitors toward B cell lineage in addition to myeloid lineages. Screening of cytokines to identify the minimum requirement of cytokines in the primary culture revealed that IL-3 and SCF were essential and that the addition of FL, and to a lesser extent IL-6 or G-CSF, to the combination of IL3 and SCF remarkably enhanced the primary colony formation and the generation of CD19+ cells in the secondary B-lymphoid culture.

Antigens, CD34↗
PubMed2000

Do mucosal defensive agents improve the cure rate when used with dual or triple therapy regimens for eradicating Helicobacter pylori infection?

BACKGROUND: Some of mucosal defensive agents have anti-Helicobacter pylori activities. However, their effectiveness in eradicating H. pylori infection has not been evaluated. AIM: To assess the additive effect of mucosal defensive agents in eradication regimens using statistical analysis. METHODS: Pertinent studies were retrieved using the Medline and the Igaku-chuo-zasshi databases in Japan, reference and congress abstract lists. Studies in which regimens consisted of dual or triple therapy with mucosal defensive agents and without them, were selected from the retrieved studies. Eradication rates were extracted from studies according to intention-to-treat analysis. We evaluated the efficacies of mucosal defensive agents by pooled relative risk of eradication rates and its 95% confidence intervals (95% CI), which were calculated by Mantel-Haenszel method. Heterogeneity among the studies in treatment effect was evaluated by a chi2-test. RESULTS: In dual therapy regimens, mucosal defensive agents demonstrated significant additive effects (pooled relative risk 1.41; 95% CI: 1.24-1.61). In triple therapy regimens, these agents did not provide significant additive effect. The clinical usefulness of specific agents could not be established, when each agent was analysed independently. CONCLUSIONS: Mucosal defensive agents improve the cure rate when used with existing dual therapy regimens for eradicating H. pylori infection.

Anti-Ulcer Agents↗
PubMed2000

Cure of Helicobacter pylori infection does not improve symptoms in non-ulcer dyspepsia patients-a double-blind placebo-controlled study.

BACKGROUND: It remains controversial whether the cure of H. pylori infection improves NUD symptoms. AIM: To conduct a double-blind placebo-controlled single centre study with concealed allocation to investigate this question. PATIENTS AND METHODS: Ninety NUD patients with H. pylori infection were randomly assigned to either the treatment group (50 patients) or placebo group (40 patients). The treatment group received omeprazole, amoxycillin, clarithromycin and the placebo group received omeprazole and placebos for 7 days. Symptoms were assessed every week for up to 12 weeks after completion of medication by a symptom questionnaire. Alteration of histological parameters for gastritis was also evaluated. RESULTS: The infection was cured in 41 out of 48 patients in the treatment group and none in the placebo group. There was no significant difference in the mean symptom scores at any assessment point up to 12 weeks between the treatment and placebo groups. Regarding histological parameters, activity and inflammation, not atrophy or intestinal metaplasia, were significantly improved in the treatment group. CONCLUSION: Although histological parameters were significantly improved in the treatment group, there was no significant improvement in symptoms of NUD in the treatment group compared to placebo.

Adult↗
PubMed2000

The incidence of reflux oesophagitis after cure of Helicobacter pylori in a Japanese population.

AIM: To investigate the incidence of reflux oesophagitis after antibacterial therapy for Helicobacter pylori infection in our patient population. METHODS: Subjects were 451 H. pylori-infected patients (primary symptom: peptic ulcer disease in 347, nonulcer dyspepsia in 100, and reflux oesophagitis in four): 11 of these patients had reflux oesophagitis on study entry. H. pylori infection was treated by a proton pump inhibitor/amoxycillin-clarithromycin regimen for either 7 or 14 days. Each patient was examined by endoscopy before treatment and more than 6 months after treatment to compare oesophageal findings. In addition, 227 patients were interviewed regarding reflux symptoms, using symptom questionnaires, before and more than 6 months after treatment. RESULTS: Among 440 patients who did not have reflux oesophagitis prior to antibacterial treatment (340 peptic ulcer patients and 100 nonulcer dyspepsia patients), 23 patients whose infection was eradicated developed reflux oesophagitis (5.4%). The 11 patients who had reflux oesophagitis prior to treatment were all successfully cured of infection. Six of these patients showed no change in their oesophagitis, while the condition improved in three and worsened in two. Symptom scores improved in 34 of the 36 patients who reported reflux symptoms. Among 19 patients who showed persistent infection, only one developed reflux oesophagitis (5.2%), while none complained of newly developed symptoms following treatment. CONCLUSIONS: Development of reflux oesophagitis after treatment of H. pylori infection was observed in a Japanese population. However, the incidence of this condition was comparable between those with persistent H. pylori infection and those in whom the infection was eradicated.

Adult↗
PubMed2000

Effects of growth factors on aspirin-induced inhibition of wound repair in a rabbit gastric epithelial cell model.

BACKGROUND: Aspirin is known to cause adverse effects, including gastric mucosal injury, and to retard gastric wound healing. Growth factors including hepatocyte growth factor (HGF), epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) have been shown to play an important role in the repair of gastric mucosal injury. AIM: To employ the cultured gastric epithelial cell model to elucidate the effects of aspirin, as well as several growth factors (HGF, EGF and IGF-I), on gastric wound repair. METHODS: Isolated rabbit gastric epithelial cells (92% mucous cells) were cultured in F-12 medium and formed a complete monolayer cell sheet in 48 h. A wound with a cell-free area of constant size (2 mm2) was then created and the wound repair process was monitored by measuring wound size every 12 h. Proliferating cells were detected by BrdU staining. Effects of aspirin (8 mM), HGF (10 ng/mL), EGF (10 ng/mL) and IGF-I (30 ng/mL) were assessed. RESULTS: Aspirin significantly retarded wound healing, but simultaneous addition of growth factors significantly accelerated wound repair compared with aspirin alone. Growth factors reversed the aspirin-induced inhibition of cell proliferation. CONCLUSION: Growth factors, including HGF, EGF and IGF-I, reversed the aspirin-induced inhibition of wound repair through their cytoprotective effects on gastric epithelial cells.

Animals↗
PubMed2000

Bifonazole (Mycospor cream) in the treatment of moccasin-type tinea pedis. Comparison between combination therapy of bifonazole cream + 10% urea ointment (Urepearl) and occlusive dressing therapy with the same agents.

Moccasin-type tinea pedis(MTTP) is a hardly curable superficial dermatomycosis primarily characterized by hyperkeratosis of the sole. In this study, we compared the usefulness of combination therapy of bifonazole (Mycospor cream) + 10% urea ointment (Urepearl) (overlapping application group = group I) with occlusive dressing therapy with the same agents (group II) in the treatment of MTTP, and obtained the following results. (1) The clinical improvement rate (percentage of "marked improvement" and "moderate improvement") was 60.4% in group I and 83.3% in group II. (2) The mycological eradication rate was 48.7% in group I and 82.1% in group II after 4 weeks of treatment and 90.9 and 96.9%, after 12 weeks of treatment, respectively. (3) The clinical utility rate (percentage of "very beneficial" and "beneficial") was 83.3% in group I and 93.8% in group II. These results indicate the superiority of both combination therapy of bifonazole + 10% urea ointment (overlapping application group) and occlusive dressing therapy with the same agents in terms of efficacy and safety for the treatment of MTTP, and suggest that they can be recommended for treatment of patients for whom it is difficult to use oral antimycotic agents or for patients who fail to respond to oral medications alone.

Administration, Topical↗
PubMed2000

Functional dyspepsia and Helicobacter pylori infection: a recent consensus up to 1999.

With accumulated evidence for a close relationship between Helicobacter pylori infection and many gastric disorders, the idea that this infection may invoke dyspeptic symptoms appears realistic. If curative therapy for H. pylori can bring about relief of symptoms in these patients, we would possess a new therapeutic tool for functional dyspepsia. Although there have been many clinical trials on this issue, the benefits of H. pylori treatment have been controversial. However, several large-scale clinical studies have been very recently published, and suggest a specific direction on this clinical question. From these results, the current consensus is that H. pylori infection does not directly affect symptoms in patients with functional dyspepsia. However, most clinical trials have been performed on Western populations, and there are few reports from Asian countries. Our recent study on the Japanese population also supported the consensus, that is, a negative relationship between H. pylori infection and symptoms in functional dyspepsia patients.

Asia↗
PubMed2000

Role of Kupffer cells and gut-derived endotoxins in alcoholic liver injury.

The hepatotoxic effects of alcohol have been described in detail, but factors responsible for its hepatotoxicity have only partially been characterized. For example, it is known that chronic ethanol ingestion increases hepatotoxicity and produces fatty liver, hepatitis and cirrhosis. However, acute ethanol consumption reduces endotoxin hepatotoxicity. It now appears that Kupffer cells participate in several aspects of these phenomena. Previously, most studies on the effects of alcohol on liver function have focused chiefly on the hepatocyte. Recently, attention has been directed towards the effect of ethanol ingestion on Kupffer cell function, which is stimulated by gut-derived endotoxins (lipopolysaccharides) via mechanisms dependent on increased gut permeability and the possible relationship between Kupffer cells and alcohol-induced liver injury. Here we will review new evidence for the proposal that Kupffer cells and endotoxins play a pivotal role in hepatotoxicity following alcohol exposure, based on studies using the continuous intragastric enteral feeding model developed by Tsukamoto and French and an acute model developed by us.

Ethanol↗
PubMed2000

p73: structure and function.

Alteration of the p53 tumor suppressor gene is a common, if not general, observation in human malignant tumors. p73 Is a novel member of the p53 family at chromosome 1p36.3, at which locus frequent defects are seen in many tumors including neuroblastoma. Besides structural similarities, the fact that p73 functions in the regulation of the cell cycle and apoptosis promotes the expansion of the research field concerning p53-associated tumor progression. In this paper, we review the structure and function of p73 as well as the mutational status in various human tumors. In addition, possibilities for new therapeutic applications with p73 for cancer cell control are discussed.

Apoptosis↗
PubMed2000

The expression of a novel natural killer inhibitory molecule, Cho-1, on the chorionic cytotrophoblast cells of successful pregnancy, but not of spontaneous abortion.

The regulatory mechanism of the recognition and cytotoxicity by natural killer (NK) cells in placental tissue remains unclarified. Previous reports indicated that monoclonal antibody Cho-1-defined molecule (Cho-1 molecule) may act as the negative regulator in the cytotoxicity by human NK cells. The Cho-1 molecule is composed of non-covalently associated cell surface molecules of approximately 200 kDa and 40 kDa. In the present study we analyzed the expression of this novel molecule in extravillous cytotrophoblast cells, which are presumed to be exposed to the cytotoxic action by maternal NK cells, from clinical cases of successful pregnancy and spontaneous abortion. By using monoclonal antibody Cho-1, our immunohistochemical data indicated that the Cho-1 molecule is clearly expressed in the cytotrophoblast cells of the early phase of successful pregnancy, but only weakly expressed in those from spontaneous abortion. The cytotrophoblast cells in the late phase (9-10 months) of pregnancy also expressed this molecule. Fluorescence-activated cell sorter analysis also showed that it is expressed on the cytotrophoblast cell surface of successful pregnancy but not on that of spontaneous abortion, suggesting that Cho-1 antigen may act as a negative regulator of the cytotoxicity by NK cells in successful pregnancy of the fetus.

Abortion, Spontaneous↗
PubMed2000

Addition of metronidazole to rabeprazole-amoxicillin-clarithromycin regimen for Helicobacter pylori infection provides an excellent cure rate with five-day therapy.

BACKGROUND: New triple therapy for eradication of Helicobacter pylori based on a proton pump inhibitor (PPI) provides a cure rate of approximately 90% with few adverse effects. Recently, a PPI-based quadruple therapy, which consists of a PPI plus bismuth-based triple therapy for 7 days, has been studied, and a sufficient eradication rate has been achieved. However, a shorter duration results in improved compliance. In this study, newly developed short-term, simple twice-daily quadruple therapy consisting of rabeprazole, amoxicillin, clarithromycin, and metronidazole (RACM) was compared with a PPI-based triple-therapy regimen for eradication of H. pylori. PATIENTS AND METHODS: This study was designed as a randomized open, prospective single-center study. Of a total of 105 H. pylori-positive patients, 55 received the RACM regimen for 5 days (rabeprazole, 10 mg bid; amoxicillin, 750 mg bid; clarithromycin, 200 mg bid; and metronidazole, 250 mg bid), and 50 received the RAC regimen for 5 days (rabeprazole, 10 mg bid; amoxicillin, 750 mg bid; and clarithromycin, 200 mg bid). Cure of the infection was assessed by HpSA (H. pylori stool antigen immunoassay) 1 month after completion of therapy. RESULTS: The rates of eradication of H. pylori by RACM versus RAC were 94.5% (95% CI, 85-99) versus 80.0% (95% CI, 66-90) by intention-to-treat analysis; 98.1% (95% CI, 90-100) versus 87.0% (95% CI, 74-95) by all-patients-treated analysis; and 98.1% (95% CI, 90-100) versus 86.7% (95% CI, 73-95) by per-protocol analysis. No major adverse effects were reported, and 98.0% of patients reported complete compliance. CONCLUSIONS: The simple twice-daily and short-term quadruple regimen for only 5 days provided an excellent eradication rate. Compliance with the regimen was high, and serious adverse effects were few. Therefore, the RACM regimen can be considered as safe and effective.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2000

Glycine prevents apoptosis of rat sinusoidal endothelial cells caused by deprivation of vascular endothelial growth factor.

Apoptosis of sinusoidal endothelial cells (SECs) is one of the initial events in the development of ischemia-reperfusion injury of the liver. Glycine has been shown to diminish ischemia-reperfusion injury in the liver and improve graft survival in the rat liver transplantation model. Here, we investigated the effect of glycine on apoptosis of primary cultured rat SECs induced by vascular endothelial growth factor (VEGF) deprivation. Isolated rat SECs were cultured in EBM-2 medium supplemented with 10% fetal bovine serum (FBS) and growth factors including 20 ng/mL VEGF for 3 days. SECs at 3 days of culture showed spindle-like shapes; however, cells started shrinking and detaching from dishes by VEGF deprivation. Apoptosis was detected by terminal deoxynucleotidyl transferase (TdT)-mediated d-uridine triphosphate (dUTP)-biotin nick end labeling (TUNEL) staining in these conditions. Control SECs contained only a few percent of TUNEL-positive cells; however, they started increasing 4 hours after VEGF deprivation, and the percentage of TUNEL-positive cells reached about 50% at 8 hours and almost 100% at 16 hours after VEGF deprivation. Interestingly, this increase in TUNEL-positive cells after VEGF deprivation was prevented significantly when glycine (1-10 mmol/L) was added to the medium, the levels being around 60% of VEGF deprivation without glycine. Furthermore, strychnine (1 micromol/L), a glycine receptor antagonist, inhibited this effect of glycine, suggesting the possible involvement of the glycine receptor/chloride channel in the mechanism. Moreover, Bcl-2 protein levels in SECs were decreased 8 hours after VEGF deprivation, which was prevented almost completely by glycine. It is concluded that glycine prevents apoptosis of primary cultured SECs under VEGF deprivation.

Animals↗
PubMed2000

Up-regulation of telomerase activity in human pancreatic cancer cells after exposure to etoposide.

Telomerase plays a critical role in the development of cellular immortality and oncogenesis. Activation of telomerase occurs in a majority of human malignant tumours, and the relation between telomerase and vulnerability to drug-mediated apoptosis remains unclear. In this study, we demonstrate, for the first time, up-regulation of telomerase activity in human pancreatic cancer cells treated with etoposide, a topoisomerase II inhibitor. Exposure of MIA PaCa-2 cells to etoposide at various concentrations (1-30 microM) resulted in two- to threefold increases in telomerase activity. Up-regulation was detectable 24 h after drug exposure and was accompanied by enhanced expression of mRNA of the human telomerase reverse transcriptase. Telomerase activation was also observed in AsPC-1 and PANC-1 cells but not in KP-3 and KP-1N cells. Furthermore, we found a negative correlation between increased telomerase activity and the percentage of dead cells after etoposide treatment. These findings suggest the existence of an anti-apoptotic pathway through which telomerase is up-regulated in response to DNA damage. This telomerase activation pathway may be one of the mechanisms responsible for the development of etoposide resistance in certain pancreatic cancer cells.

Antineoplastic Agents, Phytogenic↗
PubMed2000

Effect of serial extraction alone on crowding: spontaneous changes in dentition after serial extraction.

We examined changes in dentition after serial extraction in subjects who wore no appliances to determine the relationships between changes in dentition and improvement in dental crowding. Mandibular dental casts and lateral cephalograms from 31 subjects who had undergone serial extraction without orthodontic treatment were analyzed at 3 stages: before extraction of the deciduous canines (T1), after extraction of first premolars (T2), and at the end of the observation period (T3). Although movements of the first molar cusp and apex from T2 to T3 were significantly greater than from T1 to T2, movements of the incisor cusp and apex from T1 to T2 were significantly greater than from T2 to T3. The first molar tipped mesially from T1 to T2 but tipped distally from T2 to T3. The distal tipping of the incisor from T1 to T2 was significantly greater than from T2 to T3. These results suggest that the main changes in dentition from T1 to T2 are different from those from T2 to T3. The correlations between the annual change in the canine movement or tipping from T2 to T3 and the annual change in the irregularity index at the same time were significant. These results suggest that the canine movement or tipping contributed to the correction of the anterior crowding from T2 to T3.

Analysis of Variance↗