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Biomedical subjects

S Ota

Publications and source records attributed to S Ota.

At least 181 records · Page 10Linked to original sources
PubMed1991

A case of malignant lymphoma in the liver treated by percutaneous ethanol injection therapy under peritoneoscopic observation.

A 41-year-old woman with non-Hodgkin's lymphoma in the liver was treated with percutaneous ethanol injection therapy. Ethanol injection was performed twice under ultrasonographic guidance for a lesion inside the liver and once under peritoneoscopic observation for lesions on the surface of the liver. CT performed after treatment showed that sizes of the lesions decreased and that the lesions were not enhanced by contrast medium, indicating lack of blood supply and necrosis of the lesion. Ultrasonography performed after treatment did not show any lesions in the liver. There was no sign of recurrence or metastasis.

Adult↗
PubMed1991

Endothelin-1 secretion from cultured rabbit gastric epithelial cells.

It has been shown that endothelin-1 (ET-1) is synthesized in various extraendothelial tissues. Although ET-1 has been reported to have potent ulcerogenic action in the stomach, the synthesis and physiological roles of ET-1 in the gastric mucosa are poorly understood. The aim of the present study was to investigate whether or not cultured gastric epithelial cells secrete ET-1 and possess autocrine functions. Gastric epithelial cells from rabbits were cultured in medium supplemented with 10% FBS after isolation. ET-1 was extracted by C18 columns from serum-free culture media and measured by radioimmunoassay (RIA). Effects of ET-1 on the intracellular concentration of calcium of the cultured cells were examined with Indo-1. Prostaglandin E2 (PGE2) was measured by RIA. Primary cultures of gastric epithelial cells were mainly composed of mucous cells. ET-1 was detected in the culture medium by RIA, and 70 pg/10(6) cells/24 h of ET-1 was secreted by cultured cells. Tumor growth factor-beta (4 ng/ml) and thrombin (8 U/ml) significantly increased ET-1 secretion. Exogenously administered ET-1 up to 10(-6) M neither modulated the intracellular calcium concentration nor affected PGE2 release by these cells. These results suggest that gastric mucous cells in culture secrete ET-1. Further studies are needed to explore the possible involvement of such paracrine function in the reported ulcerogenic action of ET-1.

Animals↗
PubMed1991

SAT, a 'new' low frequency blood group antigen, which may be associated with two different MNS variants.

A new private blood group antigen, SAT, was identified in an NFLD-Japanese woman as a result of testing 10,480 blood donors with a serum containing anti-NFLD and anti-SAT. Three other sera were subsequently also shown to contain anti-SAT. The donor's family showed that SAT is inherited as a dominant character and may be associated with a weak M antigen. Serological and immunochemical analysis revealed no other aberrations in the MNS system. Study of a second SAT+Japanese blood donor and his family suggested that SAT is associated with an unusual MNS variant resulting from a hybrid glycophorin comprising the N-terminus of glycophorin A and the C-terminus of glycophorin B. The propositus appears to be homozygous for the gene that produces the putative hybrid, which differs from previously described glycophorin (A-B) hybrids by expressing no S, s or U antigen. SAT antigen, therefore, may be associated with two different MNS variants in the only two families in which it has been identified.

Animals↗
PubMed1991

[A clinical experience of rokitamycin on Campylobacter enteritis. Research Group of Rokitamycin on Infectious Enteritis].

Rokitamycin, a newly developed macrolide, was administered to a total of 107 cases, 16 years old or more, in order to evaluate its clinical efficacy, safety and usefulness on Campylobacter enteritis. Daily dosage of 600 mg of rokitamycin was administered orally in three divided doses for 5 days. Bacteriological and clinical efficacies were judged by the attending doctors from the evaluation criteria made by the committee and from the days required for improvement of diarrhea, defervescence and so on, respectively. Antibacterial activities against the isolates were tested of rokitamycin (RKM), erythromycin (EM), josamycin (JM) and ofloxacin (OFLX). The results were as follows; 41 symptomatic patients and 5 carriers were evaluated. Clinical efficacy (n = 41) was 100% (excellent; 34.1%, good; 65.9%). Bacteriological efficacy (n = 41) was 97.6%. Eight of the 9 cases with consecutive stool cultures were free of the bacteria on and after one day of the drug administration. Clinical usefulness (n = 46) was 97.8%. Slight epigastric pain was seen in only one as a side effect. The items of abnormal laboratory findings were 4 elevated GPT and/or GOT and one increased number of WBC in 4 cases. MIC90 of RKM, EM, JM and OFLX against 41 clinical isolates of C. jejuni were 1.56, 3.13, 3.13 and 0.78 micrograms/ml, respectively. Rokitamycin was considered clinically useful to treat Campylobacter enteritis.

Adolescent↗
PubMed1991

[Comparison of clinical efficacy of rokitamycin (RKM) and ofloxacin (OFLX) for the treatment of Campylobacter enteritis by a double-blind method. The Research Committee for the Effect of Rokitamycin, Research Group for Infectious Enteritis].

The clinical efficacy, safety and usefulness of Rokitamycin (RKM), a new macrolide antibiotic, were compared with those of Ofloxacin (OFLX) for the treatment of Campylobacter enteritis by a double blind method. The daily dose level of RKM or OFLX was 600 mg. They were orally administered in three divided doses for 5 days. Of 223 cases studied, 106 cases were diagnosed as Campylobacter enteritis. Ninety cases (RKM group: 50, OFLX group: 40) except for 16 excluded or drop-out cases were analysed. There was no significant difference between the two groups in any background factors. The effectiveness and usefulness was evaluated in 88 cases (RKM group: 48, OFLX group: 40). The results obtained were as follows: 1. In a total of 82 strains of Campylobacter jejuni/coli (RKM group: 42, OFLX group: 40), the bacteriological efficacy rate of RKM (95.2%) was superior to that of OFLX (70.0%) with a significant difference (p = 0.006). 2. In 76 symptomatic patients (RKM group: 42, OFLX group: 34) on the day of the beginning of drug administration, the clinical efficacy rate was 97.6% in the RKM group and 85.3% in the OFLX group with no significant difference between the two groups. 3. In 88 evaluable patients, the global clinical efficacy rate of RKM (95.8%) was superior to that of OFLX (67.5%) with a significant difference (p = 0.001). 4. Side effect was observed in 1 (1.9%) of the 54 patients in the RKM group and none of the 44 patients in the OFLX group. Slightly abnormal laboratory findings were seen in 4 (10.8%) of the 37 patients treated with RKM and 3 (9.7%) of the 31 patients treated with OFLX, but there was no significant difference between the two groups. 5. In 88 evaluable patients, the clinical usefulness of RKM (91.7%) was superior to that of OFLX (67.5%) with a significant difference (p = 0.01). From these results, RKM is considered to be a very useful agent for the treatment of Campylobacter enteritis.

Adolescent↗
PubMed1991

Role for iron in reactive oxygen species-mediated cytotoxicity to cultured rat gastric mucosal cells.

The gastric epithelium is exposed to oxygen species that are generated within the lumen. Reactive oxygen species, enzymatically generated, cause injury to cultured rat gastric mucosal cells. Much interest has been focused on the role of iron in producing oxidant-mediated injury to the gastric mucosa, because iron is a catalyst that promotes the production of .OH possibly from O2-. and H2O2 (Haber-Weiss reaction) or from H2O2 alone (Fenton reaction). With the use of an iron chelator and an iron binding protein, we examined the role of iron in producing oxidant-mediated injury to cultured gastric mucosal cells. Reactive oxygen species and H2O2 were generated by hypoxanthine-xanthine oxidase and glucose-glucose oxidase, respectively, in buffer without iron. Pretreatment with deferoxamine diminished hypoxanthine-xanthine oxidase-induced 51Cr release from prelabeled cells, dose dependently. Furthermore, addition of deferoxamine to the reactive oxygen species-generating system also protected against the injury. However, apotransferrin (which binds extracellular iron) failed to protect cells. Pretreatment with .OH scavengers was partially protective. Depletion of glutathione with diethyl maleate enhanced reactive oxygen species-mediated cytolysis; such cytolysis was inhibited by deferoxamine. Deferoxamine also decreased 51Cr release induced by glucose-glucose oxidase. We conclude that intracellular iron plays a crucial role in mediating oxygen radical damage to gastric mucosal cells. The .OH, produced from H2O2 by the iron-catalyzed Fenton reaction, seems to be the main mediator of oxidant-induced cytotoxicity to gastric mucosal cells in vitro.

Animals↗
PubMed1991

Reduced glutathione protects cultured gastric mucosal cells from suckling rats against acid.

We examined the role of reduced glutathione as a defense mechanism against acid-induced gastric mucosal cell damage in vitro. Cellular stores of reduced glutathione were depleted by reaction with diethyl maleate (DEM) or 1-chloro-2,4-dinitrobenzene (CDNB) and increased by reaction with L-cysteine. Depletion of cellular glutathione by reaction with DEM or CDNB potentiated gastric mucosal cell lysis by acid. Increase of cellular glutathione by L-cysteine decreased cell lysis by acid. Altering the cellular reduced-to-oxidized glutathione ratio by tert-butyl hydroperoxide or diamide increased cellular susceptibility to acid. Reduced glutathione is essential for glutathione peroxidase to catalyze hydrogen peroxide. We further studied whether oxygen free radicals were involved in the pathogenesis of acid-induced gastric mucosal injury in vitro. Neither superoxide dismutase, catalase, nor dimethyl sulfoxide decreased acid-induced gastric mucosal cell damage. We conclude that reduced glutathione plays an important role as a defense mechanism against acid-induced injury in cultured rat gastric mucosal cells. Production of oxygen radical in response to acid exposure may occur intracellularly, since exogenous oxygen radical scavengers, which do not gain access to the interior of cells, had no protective effect. Reduced glutathione might protect gastric mucosal cells by mechanisms other than the elimination of oxygen free radicals.

Acids↗
PubMed1991

Oxygen metabolites stimulate mucous glycoprotein secretion from cultured rat gastric mucous cells.

The aims of this study were to investigate the interaction between oxygen radicals and mucus secretion from cultured rat gastric mucous cells, and to assess the role of prostaglandin production in the modulation of mucus secretion in vitro. Xanthine oxidase in the presence of hypoxanthine caused a dose-dependent increase in the presence of hypoxanthine caused a dose-dependent increase of mucus secretion, as assessed by release of [3H]glucosamine from prelabeled cells, whereas xanthine oxidase or hypoxanthine alone did not. Xanthine oxidase (10 mU/ml) increased release of [3H]glucosamine by 57 +/- 6% compared with control values (P less than 0.001). Catalase (3,000 U/ml) inhibited xanthine oxidase-induced mucus secretion by 69 +/- 9% (P less than 0.01), whereas superoxide dismutase did not. Pretreatment with deferoxamine, an inhibitor of hydroxyl radical generation through chelating ferric ion, diminished oxygen radical-induced mucus release to control values. Xanthine oxidase dose dependently stimulated prostaglandin E2 (PGE2) production, which was blocked by catalase but not by superoxide dismutase. However, oxygen radical stimulation of mucus secretion was not inhibited by the addition of indomethacin. Moreover, PGE2, exogenously administered, did not significantly accelerate mucus secretion. Stimulation of mucus secretion by oxygen radicals was not accompanied by increased 51Cr release or by leakage of intracellular lactate dehydrogenase. These results suggest that oxygen species, particularly hydroxyl radical, stimulate mucous glycoprotein secretion from cultured rat gastric mucous cells. However, it seems unlikely that prostaglandin production mediates the oxygen species-induced stimulation of mucus secretion.

Animals↗
PubMed1991

Antioxidant defenses of cultured gastric cells against oxygen metabolites: role of GSH redox cycle and endogenous catalase.

Gastric mucous epithelial cells may represent a first line of defense against reactive oxygen species that are generated within the gastric lumen. However, little is known about their defenses against oxidant species. This study examined the importance of the glutathione (GSH) redox cycle and of endogenous catalase as antioxidant defenses in cultured gastric mucous cells. Cultured rat gastric mucous cells were exposed to H2O2 generated by glucose oxidase acting on glucose or to nascent H2O2 for 5 h. Cytotoxicity was quantified by measuring 51Cr release from prelabeled cells. The effects of inhibition of the GSH redox cycle and of endogenous catalase were examined. Glucose oxidase caused a dose-dependent increase of 51Cr release. Similarly, nascent H2O2 damaged the cells dose dependently. Pretreatment with 1,3-bis(chloroethyl)-1-nitrourea (inhibitor of GSH reductase) dose dependently increased glucose oxidase-induced 51Cr release. Preincubation with buthionine sulfoximine (inhibitor of gamma-glutamyl-cysteine synthetase), which lowered intracellular GSH content, enhanced glucose oxidase-induced damage in a dose-dependent manner. Pretreatment with diethyl maleate, which covalently binds GSH as catalyzed by GSH transferase, also enhanced the sensitivity to lysis by glucose oxidase. However, inhibition of endogenous catalase activity by 3-amino-1,2,4-triazole did not significantly alter glucose oxidase- or nascent H2O2-induced 51Cr release. These results suggest that the GSH redox cycle rather than endogenous catalase plays a critical role in intracellular antioxidant defense in cultured gastric mucous cells.

Animals↗
PubMed1991

Tetraprenylacetone promotes healing process of ethanol-induced gastric damage in the rat.

Tetraprenylacetone (TPA: teprenon, geranylgeranylacetone) is a novel anti-ulcer agent developed in Japan. The aim of this study was to test whether TPA has the ability to promote the healing process of rat gastric mucosal injury induced by absolute ethanol (ET). Fasted rats received orally 5 ml/kg of absolute ET. Sixty minutes later, TPA (200 mg/kg) or saline (control) was administered intragastrically. Thereafter, the same dose of TPA or saline was given orally every 8 hours. To investigate the role of endogenous prostaglandins, indomethacin was given intraperitoneally every 8 hours. Twenty four or 48 hours after the first administration of TPA or saline, rats were sacrificed and the stomachs were removed. Administration of TPA significantly reduced lesion indices from 100 +/- 12.9% (control) to 57.0 +/- 12.8% (24 hours, P less than 0.05) and from 100 +/- 15.3% (control) to 17.6 +/- 3.4% (48 hours, P less than 0.01). Addition of indomethacin did not significantly affect this effect of TPA. Ultrastructural studies revealed that TPA stimulated regeneration of gastric mucosa damaged by ET after 24 and 48 hours. These results indicate that TPA has the ability to promote the healing process of gastric mucosal damage induced by absolute ET. It is, however, unlikely that endogenous prostaglandins are involved in this promotive effect of TPA on the healing process of gastric injury.

Animals↗
PubMed1991

The effect of cimetidine on adaptive cytoprotection by mild irritant dose of HCl in the rat gastric mucosa.

While cimetidine (CIM) is strikingly effective in inhibiting gastric acid secretion, its effect on the defensive mechanisms of the gastric mucosa has been controversial. The aims of the present study were to test if administration of CIM at an antisecretory dose is protective against acid-induced injury and to assess its effect on adaptive cytoprotection induced by non-necrotizing concentrations of HCl in rats. A dose of 100 mg/kg of CIM was administered once, or twice a day for 5 days intraperitoneally. To study the effect of CIM on HCl-induced damage, 0.6 N HCl was given orally one hour after the last administration of CIM. To study the effect of CIM on adaptive cytoprotection, 0.35 N HCl was given orally one hour after the last administration of CIM. Fifteen minutes later, 0.6 N HCl was given orally. Thirty minutes after the administration of 0.6 N HCl, the stomach was removed and ulcer indices were calculated. Pretreatment with CIM did not prevent 0.6 N HCl induced gastric damage. Prior administration of 0.35 N HCl significantly reduced ulcer indices caused by 0.6 N HCl. Short or long term treatment with CIM did not have significant effects on the reduction of ulcer indices. These results suggest that CIM at an antisecretory dose neither acts as a protective agent nor modulates the protective process of the gastric mucosa.

Adaptation, Physiological↗
PubMed1991

[The effect of pyeloplasty on renal function in children with unilateral ureteropelvic junction obstruction. Investigation of the split renal function using DMSA renal uptake rate].

Pre- and post-operative changes of renal function in twenty children (10 were younger than 2 years old) with unilateral hydronephrosis due to ureteropelvic junction obstruction were studied on the basis of DMSA renal uptake rate. A marked increase in DMSA renal uptake rate was observed in thirteen cases (65%) after pyeloplasty on the obstructed side. Among them eight children were younger than 2 years old. In 6 children younger than 2 years old, a remarkable increase of DMSA renal uptake rate after reconstructive operation was recognized not only on the obstructed side but also on the contralateral normal side. These tendency could not be observed in those older than 2 years old. These results suggest that, in the young children, the obstructed kidney inhibits the contralateral normal and compensatory renal growth, and that the relief of obstruction eliminates this inhibition and causes the renal growth spur in a normal kidney. We conclude that it is essential to correct unilateral ureteropelvic junction obstruction before two years of age if an improvement of renal function not only on the obstructed side but also on the normal side is to be expected.

Adolescent↗
PubMed1991

[T4 advanced lung cancer: results of surgical treatment and indications of surgical resection].

A total of 1,289 patients with primary lung cancer were surgically treated at our hospital from January 1953 to December 1985. Surgical treatment for T4 lung cancer was studied in 93 patients who had pulmonary resections. The relationships between histologic type, stage, method of resection, curability, nodal involvement, pleural involvement, site of invasion, pleural metastasis, pleural effusion, combination therapy, and the survival rate were analyzed. The survival rate of 93 patients with T4 lung cancer was 17% at 3 years and 7% at 5 years. Three-year survival rate of 39 patients with adenocarcinoma, 34 patients with squamous cell carcinoma, and 9 patients with large cell carcinoma was 7%, 23%, and 14%, respectively. Two-year survival rate of 6 patients with small cell carcinoma was 17%. Four-year survival rate of 14 patients who had complete resection was 33%. On the other hand, four-year survival rate of 77 patients who had incomplete resection was 7%. Three-year survival rate of 6 patients with N0 disease, and 19 patients with N1 disease, 46 patients with N2 disease, and 22 patients with NX disease was 40%, 39%, 0%, and 15%, respectively. Two patients, who had partial resection of the left atrium because carcinoma made an invasion upon it, had survived more than 5 years. All patients with esophageal invasion or tracheal invasion had died within a year. Indications of surgical resection for patients with T4 lung cancer should be limited to patients with N0 and N1 disease. Radical pulmonary resection can be performed in patients who are expected to have complete resection.

Adult↗
PubMed1990

Clinical and prognostic assessment of patients with resected small peripheral lung cancer lesions.

One hundred fifteen patients with small (less than or equal to 2 cm in diameter) peripheral lung cancer lesions underwent surgical treatment in the Department of Surgery, The Research Institute for Chest Diseases and Cancer, Tohoku University, Miyagi Prefecture, Japan. The authors investigated several prognostic factors of these cases. The 5-year survival rate of these 115 patients was 70%. Various factors such as histologic type, nodal involvement, pleural involvement, pathologic stage, and curativity of the operation were revealed to affect survival significantly. In patients with and without nodal involvement, there was no significant difference between the survival rate of patients with lung cancer lesions smaller than 2 cm and those with lesions 2.1 to 3 cm. However, the rate of lymph node metastasis was significantly different in the group with lesions smaller than 2 cm compared with those with lesions 2.1 to 3 cm (21% versus 43%, respectively).

Adenocarcinoma↗
PubMed1990

A monolayer culture of gastric mucous cells from adult rabbits.

A new method for the primary monolayer cultures of adult rabbit gastric mucous cells has been developed. Rabbit gastric mucosal cells were isolated with etylenediaminetetraacetic acid and collagenase. Cells were cultured in Coon's modified Ham's F-12 medium supplemented with 10% fetal bovine serum, 15mM HEPES buffer, antibiotics, and antimycotic. The cells reached confluency on days 3-4. Histochemically 92% of the cells contained PAS positive gramules (mucous cells), 3% of cells showed a strong reaction for succinic dehydrogenase activity (parietal cells), 2% of the cells showed positive granules by Bowie staining (chief cells), and G6PDH staining was positive in 5% of the cells (surface mucous cells). Fibroblasts were rarely seen until day 7 (less than 1%). Thus rabbit cultured gastric cells were considered to be mainly comosed of mucous neck cells. These cells produced prostaglandin (PG) E2 and PGI2. Quantitatively cultured cells synthesized 1.475 +/- 0.039 ng/mg protein/hour of PGE2 and 0.244 +/- 0.042 pg/mg protein/hour of PGI2. This relatively simple and convenient technique provides a useful model for the study of cellular functions of gastric mucosa.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

Protective role of intracellular glutathione against ethanol-induced damage in cultured rat gastric mucosal cells.

This study investigated whether intracellular glutathione is cytoprotective against ethanol-induced injury to cultured rat gastric mucosal cells in vitro. Secondly, it investigated whether reduced glutathione or oxidized glutathione is responsible for this cytoprotection. Cytolysis was quantified by measuring 51Cr release from prelabeled cells. Concentrations of ethanol greater than 12% caused cell damage and increased 51Cr release in a dose-dependent and time-related fashion. When a substrate for glutathione synthesis, N-acetyl-L-cysteine, was provided to cultured cells for 4 h before challenge with ethanol, cytolysis was significantly decreased corresponding with an increase in cellular glutathione content. Pretreatment with diethyl maleate, which depletes reduced glutathione without forming oxidized glutathione, potentiated ethanol-induced cell damage in a dose-dependent manner with the decrease of cellular glutathione content. The administration of tert-butyl hydroperoxide (which is specifically reduced by glutathione peroxidase to generate oxidized glutathione from reduced glutathione) or diamide (which nonenzymatically oxidizes reduced glutathione to oxidized glutathione) enhanced ethanol injury. We conclude that in cultured gastric mucosal cells, (a) intracellular glutathione maintains integrity of gastric mucosal cells against ethanol in vitro; and (b) reduced glutathione rather than oxidized glutathione is responsible for this cytoprotection. We postulate that the presence of reduced glutathione is essential to allow glutathione peroxidase to catalyze the ethanol-generated toxic oxygen radical, hydrogen peroxide.

Acetylcysteine↗
PubMed1990

Role of oxygen radicals in ethanol-induced damage to cultured gastric mucosal cells.

We have examined the role of oxygen radicals in ethanol-induced damage to cultured rat gastric mucosal cells. Cultured cells exposed to ethanol produced superoxide anion, as assessed by the reduction of cytochrome c, in a time-related fashion. The production of superoxide anion increased dose dependently as the concentration of ethanol increased. Cellular damage increased in a similar fashion to the production of superoxide anion. Both superoxide dismutase (SOD) and catalase diminished ethanol-induced injury dose dependently. SOD and catalase were able to maintain their enzymatic activities in the presence of 15% ethanol, respectively. Pretreatment with deferoxamine, an iron-chelating agent, decreased ethanol-induced injury dose dependently. Furthermore, dimethyl sulfoxide decreased ethanol-induced damage dose dependently. We conclude that cultured gastric mucosal cells exposed to ethanol generate oxygen radicals and that the production of oxygen radicals is closely linked with ethanol-induced damage to the cells. Hydroxyl radical, produced by the iron-catalyzed Haber-Weiss reaction, seems to be the main mediator of ethanol-induced damage to gastric mucosal cells in vitro.

Animals↗