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S Ota

Publications and source records attributed to S Ota.

At least 127 records · Page 7Linked to original sources
PubMed1995

Relationships between metal ions and oxygen free radicals in ethanol-induced damage to cultured rat gastric mucosal cells.

The current study investigated whether metal ions were cytoprotective against ethanol-induced injury to cultured rat gastric mucosal cells in vitro. Secondly, the relationships between oxygen free radicals and cytoprotection by metal ions were examined. Cultured cells exposed to ethanol produced superoxide anion, as assessed by reduction of cytochrome c, in a time-related fashion, and the production of superoxide anion increased dose-dependently as the concentration of ethanol increased. Cellular damage increased proportionately to the production of superoxide anion. ZnCl2, AlCl3, CoCl2, CuCl2, and CdCl2 significantly diminished ethanol-induced injury dose-dependently. All of the agents studied decreased the reduction of cytochrome c in ethanol-induced damage dose-dependently. These results led to the conclusions that: (1) cultured rat gastric mucosal cells exposed to ethanol generate oxygen free radicals; (2) the production of oxygen free radicals is closely linked with ethanol-induced damage to the cells; and (3) metal ions decrease ethanol-induced gastric mucosal cell damage in vitro. Metal ions protect cultured rat gastric mucosal cells from ethanol-induced damage in which oxygen free radicals participate.

Aluminum Chloride↗
PubMed1995

Clinical efficacy of lansoprazole-amoxicillin treatment in eradicating Helicobacter pylori: evaluation by the polymerase chain reaction method.

The clinical efficacy of lansoprazole plus amoxicillin treatment in eradicating Helicobacter pylori was examined in peptic ulcer patients. H. pylori eradication was assessed by the polymerase chain reaction (PCR) method in addition to conventional methods. Fifteen H. pylori-positive patients with active peptic ulcers (10 duodenal ulcer patients and 5 gastric ulcer patients) were given lansoprazole 30 mg/day from day 1 to day 56 and amoxicillin 1,500 mg/day from day 15 to day 28. Four weeks after the end of treatment, no H. pylori organisms were detected in 9 of 15 patients (60%) as assessed by the rapid urease test and in 10 of 15 patients (67%) as assessed by bacterial culture. However, only three patients were negative for H. pylori when evaluated by the PCR method. Therefore, although lansoprazole plus amoxicillin treatment appears to be promising, a very small number of H. pylori organisms are apparently able to survive such treatment, which may result in the recurrence of H. pylori colonization in some patients.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

Hepatocyte growth factor is the most potent endogenous stimulant of rabbit gastric epithelial cell proliferation and migration in primary culture.

Various growth factors are suggested to be involved in gastric mucosal repair. Our previous studies have shown that exogenous hepatocyte growth factor (HGF) has a proliferative effect on gastric epithelial cells. In the present study, comparison of the maximum proliferative effects and the optimum concentrations of several growth factors revealed that HGF was the most potent mitogen for gastric epithelial cells, as is the case for hepatocytes. Restitution of gastric epithelial cell monolayers was assessed using a round wound restitution model. HGF was the most effective agent for facilitating gastric epithelial restitution among those tested. A binding assay revealed specific binding of HGF to its receptor on gastric epithelial cells. Northern blot analysis confirmed the expression of specific HGF receptor mRNA (c-met) by gastric epithelial cells but not by gastric fibroblasts. To investigate endogenous HGF production, we determined the effect of gastric fibroblast-conditioned medium on epithelial proliferation and restitution. The conditioned medium produced similar effects to HGF and its activity was neutralized by an anti-HGF antibody. In addition, expression of HGF mRNA was detected in gastric fibroblasts but not in gastric epithelial cells. Our immunohistochemical study confirmed these in vitro data by means of demonstrating the existence and localization of HGF at human native gastric mucosa. HGF was localized at fibroblasts under the epithelial cell layer around gastric ulcers. These results suggest that HGF may be a potent endogenous promotor of gastric epithelial cell proliferation and migration, and may contribute to gastric mucosal repair through a paracrine mechanism.

Animals↗
PubMed1995

Expression of multidrug resistant gene (mdr-1/P-glycoprotein) in a megakaryoblastic cell line, CMK, and its enhancement during megakaryocytic differentiation.

Multidrug resistance is a severe clinical problem in the chemotherapy of malignant disease. Acute megakaryoblastic leukemia (AMKL) is a rare form of childhood leukemia, and is often resistant to many anti-cancer chemotherapeutic drugs. Here we report the expression of the mdr-1/P-glycoprotein in a cell line, CMK, established from a patient with AMKL. Expression of mdr-1 mRNA in CMK11-5 cells, a well differentiated subline, was higher than in CMK6 cells, a poorly differentiated subline. The level of P-glycoprotein was also higher in CMK11-5 cells. The cytokines interferon-gamma (IFN-gamma), GM-CSF and IL-3, which were shown to induce megakaryocytic differentiation of CMK cells, enhanced the expression of the mdr-1 mRNA and levels of P-glycoprotein. These results imply that differentiated megakaryocytic cells may have higher levels of the P-glycoprotein expression, suggesting a possible normal physiological function of P-glycoprotein in mature megakaryocytes.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Expression of MDR-1/P-glycoprotein in childhood acute megakaryoblastic leukemia cells.

Multidrug resistance is a major clinical problem in chemotherapy of malignant disease. Acute megakaryoblastic leukemia (AMKL) is a rare form of childhood leukemia, and is often more resistant to many anticancer chemotherapeutic drugs compared to other types of childhood leukemia. There have been reports of the increased expression in hematologic malignancy of multidrug resistant (mdr-1) gene, which encodes for a transmembrane glycoprotein P-glycoprotein that acts as an efflux pump for structurally unrelated chemotherapeutic drugs. We investigated the malignant cells of 15 newly diagnosed childhood AMKL patients by immunocytochemical analysis and found P-glycoprotein expression in all samples from these patients. RNA prepared from five patients at the time of presentation confirmed the expression of mdr-1 specific message in all cases by Northern blot analysis. These results imply that malignant cells from all childhood AMKL might express the mdr-1/P-glycoprotein.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

[Multicentric Castleman's disease with lymphoid interstitial pneumonia died of aggressive course with adult respiratory distress syndrome].

A 49-year-old man was admitted to our hospital with anemia and hypergammaglobulinemia. Physical examination revealed superficial lymph node swelling and no hepatosplenomegaly. Laboratory findings showed WBC 5,300/microliters with normal hemogram, microcytic and hypochromic anemia. Total protein was 11.5 g/dl and immunoglobulinemia (IgG 10,100 mg/dl, IgA 295 mg/dl, IgM 160 mg/dl) was observed without M-component in serum and urine. The CD4/CD8 ratio of lymphocyte subsets was 0.58 and the tuberuculin skin test was negative. Urinary protein was positive and renal biopsy disclosed plasma cell infiltration. Lymph node biopsy revealed multiple lymphoid follicles and infiltration of plasma cells in the interfollicular areas. A diagnosis of multicentric Castleman's disease (MCD) was made baredon clinical findings and lymph node biopsy. After therapy with plasmapheresis and the CHOP regimen, he was given etoposide. Although discharged with clinical improvement and a decrease of serum IgG, he was readmitted because of pyrexia after 4 days and died of pneumonia with adult respiratory distress syndrome. The autopsy revealed lymphoid interstitial pneumonia. It seems important to notice that some of MCD have poor prognoses because of accompanying immunodeficiency.

Castleman Disease↗
PubMed1995

[A case of necrotizing sarcoid granulomatosis].

A 60-year-old woman was admitted to our hospital because of progressive cough and chest pain for 2 months. She also complained of exertional dyspnea. Bilateral diffuse infiltlative shadows were found on the chest roentogenogram. Ground-glass opacity in the middle lobe and lingula, and subpleural patchy consolidation were seen on the computed tomogram of the chest. Arterial oxygenation and diffusing capacity were low. The level of angiotensin-converting enzyme in serum was normal, but that of lysozyme was high. In the BAL (broncho-alveolar lavage) fluid, total cell count and the number of lymphocytes were high, and the CD 4/8 ratio of the lymphocytes was high. Open lung biopsy revealed numerous confluent sarcoid granulomas with necrosis, which strongly correlated with severe vasculitis. After necrotizing sarcoid granulomatosis was diagnosed, prednisolone was administered, which resulted in improvement of symptoms and disappearance of chest-radiograph shadows. Necrotizing sarcoid granulomatosis may be seen as a variant type of sarcoidosis. However, clinical findings including the chest-radiograph shadows and clinical course of this case differ from those of ordinary sarcoidosis. These clinical findings can be attributed to severe vasculitis, as revealed by histological examination.

Female↗
PubMed1994

Growth regulation of rabbit gastric epithelial cells and protooncogene expression.

We recently developed a primary culture system for gastric epithelial cells from adult rabbits that allows the investigation of growth regulation at the cellular level. In this study, we demonstrated that epidermal growth factor (EGF), insulin, and dibutyryl adenosine 3',5'-cyclic monophosphate (dBcAMP) all stimulated cell proliferation. Insulin and dBcAMP potentiated the stimulation of cell proliferation by EGF, while transforming growth factor-beta 1 (TGF-beta 1) inhibited it. Expression of c-fos and c-myc was induced in response to the stimulation by these growth regulators, but the degree of expression did not necessarily correlate with the effects of these agents on cell proliferation. In conclusion, EGF, insulin, and dBcAMP were positive growth regulators, while TGF-beta 1 was a negative regulator in gastric epithelial cells. These growth modulators may exert their effects by distinct pathways from a standpoint of the expression of c-fos and c-myc.

Animals↗
PubMed1994

Pseudomyxoma peritonei due to adenocarcinoma of the lung: case report.

A rare case of pseudomyxoma peritonei whose primary site was presumed to be the lung is reported. A 76-year-old woman was admitted to Hospital presenting with progressive abdominal distention. She had been admitted twice, 2 and 1 year previously for the evaluation of high plasma carcinoembryonic antigen (CEA) level, of 11.6 ng/ml. Chest computed tomography (CT) scan and chest X-ray film on the third admission revealed a nodular lesion in the left lower lung field, and transbronchial lung biopsy (TBLB) revealed mucus-producing tall columnar epithelial carcinoma. Paracentesis revealed gelatinous ascitic fluid. At laparotomy, appendix and ovary were normal, and there were many small cystic tumors on the peritoneal surface and omentum. The patient died 2 years later, after repeated episodes of dynamic ileus. The lung and abdominal tumors gradually increased in size during the 2-year period, but she developed no respiratory symptoms. Based on both the clinical and pathophysiological findings, the final diagnosis made was pseudomyxoma peritonei whose origin was a lung adenocarcinoma.

Adenocarcinoma↗
PubMed1994

Churg-Strauss syndrome (allergic granulomatous angiitis) with multiple perforating ulcers of the small intestine, multiple ulcers of the colon, and mononeuritis multiplex.

A case of Churg-Strauss syndrome with multiple perforations of the small intestine is described. A 31-year-old woman was admitted with a complaint of epigastric pain. She had a history of bronchial asthma. One week before admission, white blood cell count was 20,800/mm3 with 59% eosinophils. Neurological examination on admission disclosed mononeuritis multiplex with paresthesia in both the lower and upper extremities. At colonoscopy, there were scattered aphthous ulcers in the colon. Ophthalmological examination revealed allergic conjunctivitis. After admission, hypereosinophilia increased to as high as 36,000/mm3. Oral administration of prednisolone (60 mg/day) was begun. On the 3rd day of the treatment, the eosinophil count decreased dramatically, to 400/mm3, while severe abdominal pain developed. Since abdominal X-ray film revealed free air in the abdominal cavity, emergency laparotomy was performed and multiple intestinal ulcers with perforations were found. Partial ileectomy was performed. Pathological findings of the resected specimen were interpreted as a necrotizing angiitis with extravascular granuloma. Since the operation, the patient has been asymptomatic, except for neurological symptoms. Hypereosinophilia has decreased without treatment to counts averaging 270/mm3, within 3 months. On the basis of the clinical features and histopathological findings, a diagnosis of Churg-Strauss syndrome was established.

Adult↗
PubMed1994

Protection of cultured rat gastric cells against oxidant-induced damage by exogenous glutathione.

BACKGROUND/AIMS: Reduced glutathione (GSH) is an intracellular protectant against oxidants. The present study determined whether extracellular GSH protects against oxidant damage or whether an uptake system of GSH is present in cultured gastric cells. METHODS: Hydrogen peroxide was generated by glucose oxidase and glucose. Cytotoxicity was assessed by 51Cr release. Intracellular GSH was assayed by the method of Tietze. RESULTS: Pretreatment with extracellular GSH decreased H2O2-induced 51Cr release. Treatment with GSH enhanced cellular GSH content. Protection by pretreatment with GSH was prevented by buthionine sulfoximine (an inhibitor of gamma-glutamylcysteine synthetase). Enhancement of intracellular GSH was also prevented by buthionine sulfoximine. Acivicin (an inhibitor of gamma-glutamyl transpeptidase) prevented intracellular accumulation of GSH from extracellular GSH. Cysteine was effective in preventing damage and enhancing intracellular GSH content, whereas both glutamine and glycine were not. CONCLUSIONS: Extracellular GSH protects cultured gastric cells from H2O2 damage by accelerating intracellular GSH synthesis; this is mediated by membrane-bound gamma-glutamyl transpeptidase acting on extracellular GSH (which supplies these cells with cysteine) and then by intracellular gamma-glutamylcysteine synthetase.

Animals↗
PubMed1994

P2 purinergic receptor regulation of mucus glycoprotein secretion by rabbit gastric mucous cells in a primary culture.

BACKGROUND/AIMS: Physiological regulation of gastric mucus secretion has not been well studied. The present study investigated the effects of adenosine 5'-triphosphate (ATP), a P2 purinergic receptor agonist, and its analogues on gastric mucus secretion using gastric mucous cells in a primary culture. METHODS: A monolayer culture of gastric mucous cells from adult rabbits were prepared after enzyme digestion. Mucus secretion was estimated from the release of [3H]glucosamine from prelabeled cells. Intracellular calcium concentration ([Ca2+]i) was monitored by a Ca(2+)-sensitive probe, indo-1. Prostaglandin E2 (PGE2) in the media was measured by an enzyme-linked immunoassay. RESULTS: ATP significantly stimulated mucus secretion by these cells at nontoxic doses in a dose-dependent fashion. The order of potency of ATP analogues stimulating mucus secretion was alpha beta-methylene ATP > ATP > 2-methylthio ATP, whereas adenosine, a P1 purinergic receptor agonist, had no effect. ATP also induced an elevation of [Ca2+]i in a dose-dependent fashion. The efficacy of ATP analogues to increase [Ca2+]i showed a similar potency to their actions on mucus secretion. ATP increased PGE2 at relatively higher concentrations, whereas indomethacin did not block ATP-induced increase of mucus secretion. CONCLUSIONS: These results suggest that ATP stimulates mucus secretion by gastric mucous cells through P2 purinergic receptors; this appears to be mediated by intracellular calcium not by endogenous PGE2.

Adenosine↗
PubMed1994

Stimulation of prostaglandin E2 release from cultured rabbit gastric cells by sodium deoxycholate.

Although bile salts are irritants in the gastric mucosa, their effects on prostaglandin (PG) release have not been well studied. We investigated the effects of bile salts on PGE2 release and the possible mechanisms involved. Cultured rabbit gastric mucous epithelial cells were studied. PGE2 was measured by radioimmunoassay. Intracellular free Ca2+ concentration was measured with Ca2+ fluorescent dye indo-1 AM. Dihydroxy bile salts, such as chenodeoxycholate and deoxycholate (DC), dose-dependently increased PGE2 release, while non-dihydroxy bile salts did not. Since agents involved in the cellular signal transduction system have been reported to play important roles in PG release, the possible involvement of Ca2+, calmodulin, and protein kinase C (PKC) in DC-induced PGE2 release was studied. Deprivation of Ca2+ from the medium blocked DC-induced PGE2 release. Lanthanum (La3+), which displaced surface-bound Ca2+, suppressed DC-induced PGE2. However, BAPTA (a chelator of intracellular Ca2+) did not decrease it. Neither calmodulin inhibitors nor PKC inhibitors altered DC-induced PGE2 release. DC increased intracellular free Ca2+ concentrations. This effect was blocked by deprivation of Ca2+ from the medium. Quinacrine (a phospholipase A2 inhibitor) blocked DC-induced PGE2 release. These results suggest that in cultured rabbit gastric cells, deoxycholate stimulates PGE2 release mainly through the influx of extracellular Ca2+.

Animals↗
PubMed1994

Sertoli-stromal cell tumor containing metastatic lung cancer tissue.

A patient with a Sertoli-stromal cell tumor (SSCT) that contained metastatic lung cancer tissue is described, the first such report. The left ovarian tumor, which developed in a patient known to have lung cancer, mainly exhibited the histology of SSCT with a retiform pattern, and included a component of well-differentiated adenocarcinoma. Immunohistochemical specific stain for surfactant distinguished the adenocarcinoma from the primary ovarian tumor.

Aged↗
PubMed1994

A carcinoma in situ arising in an endocervical polyp--a case report.

A rare case of a carcinoma in situ arising from an endocervical polyp is described. The covering epithelium of the polyp transformed gradually into a carcinoma in situ via squamous metaplasia and dysplasia, spreading horizontally with glandular involvement, and colliding with the surface columnar cells. The lack of tumor tissue in the pedicle and adjacent cervical region confirms the case was a carcinoma in situ originating from the surface epithelium of the endocervical polyp.

Adenomatous Polyps↗
PubMed1994

[Eosinophilic meningo-encephalo-myelitis due to Toxocara canis].

A 21-year-old woman was admitted to our hospital because of frontal headache, low-grade fever and convulsion. The patient had long been in a close contact with a dog. Neurologic examination revealed meningeal irritation signs and cerebellar ataxia. Slight leukocytosis with an increased rate of eosinophils (23.2%) was present. A lumbar puncture yielded 330 leukocytes/microliters with 30% of eosinophils; protein, 55 mg/dl; and increased IgG synthesis, 43.6 mg/day. The antibody titer against Toxocara canis was positive both in serum and in CSF by the use of immunoblotting assay, Ouchterlony, indirect immunofluorescence and ELISA. Cranial MRI showed a number of lesions located mainly cortically or subcortically, which had a hyperintense appearance on T2-weighted images and were clearly enhanced with Gd-DTPA. A diagnosis of eosinophilic meningoencephalo-myelitis due to Toxocara canis was made. In spite of the treatment with diethylcarbamazine and prednisolone, other lesions including cervical cord and optic nerves developed. Although CSF antibodies against Toxocara canis were reduced in titer, neurologic symptoms relapsed, raising the possibility that some allergic mechanisms may, at least in part, be responsible for this neurologic complication.

Adult↗