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Biomedical subjects

M Tada

Publications and source records attributed to M Tada.

At least 253 records · Page 14Linked to original sources
PubMed1995

Methylmercury-injury effect on tube formation by cultured human vascular endothelial cells.

The effect of methylmercury chloride (MeHg) on growth and tube formation by cultured human umbilical vein endothelial cells (HUVECs) was investigated. HUVECs were collected by enzymatic digestion with collagenase. Precultivation of HUVECs with MeHg at concentrations of 1.0-50.0 mumol/L exerted negligible effects on the viable cell number, while the viable cell number was slightly reduced at 100 mumol/L and fell to zero at concentrations exceeding 500.0 mumol/L MeHg. The viable cell number was depressed in a concentration-dependent manner. Tube formation was studied by culturing the cells on gelled basement membrane matrix (Matrigel). Treatment of HUVECs with 0.1-5.0 mumol/L MeHg for 24 h inhibited tube formation dose-dependently. Fetal bovine serum (FBS) increased tube formation in a dose-dependent manner, with half-maximum stimulation of tube formation at approximately 3.4% FBS. The length of tube formation decreased time-dependently at concentrations of 0.1 and 1.0 mumol/L MeHg. Pretreatment of Matrigel with 1 mumol/L MeHg before the cell seeding reduced the tube formation by HUVECs. These results suggest that the growth and tube formation by HUVECs is susceptible to MeHg cytotoxicity, and that MeHg could be injurious to endothelial cell function.

Cell Count↗
PubMed1995

The effect of methylmercury (CH3HgCl) on the production of endothelium-derived relaxing factor (EDRF) by cultured human umbilical vascular endothelial cells based on its anti-aggregatory effect on human platelets.

The effect of methylmercury (CH3HgCl) on the production of endothelium-derived relaxing factor (EDRF) by cultured human umbilical vascular endothelial cells (HUVECs) based on its anti-aggregatory effect on human platelets was examined. HUVECs were harvested from umbilical veins by collagenase treatment. The platelet aggregation test was performed with cuvettes lined with HUVECs. Platelet aggregation induced by 0.05 units thrombin/ml was inhibited in the presence of HUVECs. This HUVEC-dependent anti-platelet aggregatory effect was enhanced by the addition of bradykinin (10 nmol/L), which stimulates the production of EDRF. Indomethacin (IND, 1 mumol/L) reduced the HUVEC-dependent anti-platelet aggregatory effect. The effect of NG-monomethyl-L-arginine L-NMMA, 100 mumol/L), an inhibitor of nitric oxide synthase (NOS) in endothelial cells, on HUVECs pretreated with IND showed almost complete platelet aggregation similar to results without HUVECs. The anti-platelet aggregatory effect of HUVECs pretreated with IND seemed to depend mainly on EDRF. Methylmercury (MeHg) (20-50 mumol/L) induced dose-dependent platelet aggregation in cuvettes, without HUVECs. Methylmercury (30 mumol/L) induced less platelet aggregation in the presence of HUVECs than in their absence. The degree of inhibitory effect by HUVECs on MeHg-induced platelet aggregation was reduced dose-dependently (30-50 mumol/L MeHg). Methylmercury-induced platelet aggregation at 50 mumol/L MeHg with or without HUVECs was similar. These findings suggest that this simple new experimental system is useful for assessing the production of EDRF by HUVECs, and show that MeHg inhibits the production of EDRF by HUVECs, which may be involved in the etiology of cardiovascular diseases such as hypertension and arteriosclerosis.

Arginine↗
PubMed1995

Antibacterial properties of lansoprazole alone and in combination with antimicrobial agents against Helicobacter pylori.

The activities of various types of antiulcer agents against Helicobacter pylori strains were determined by an agar dilution method. Among the compounds tested, benzimidazole proton pump inhibitors were found to have significant activity against this organism. The activity of lansoprazole was fourfold more potent than that of omeprazole and bismuth subsalicylate, with MICs ranging from 1.56 to 25 micrograms/ml. Exposure of Helicobacter pylori to lansoprazole led to an extensive loss of viability as well as suppression of virulence factors such as motility, adhesiveness to epithelial cells and urease activity. The combination of lansoprazole with antimicrobial agents such as penicillins, cephalosporins, macrolides, tetracyclines, aminoglycosides, quinolones, metronidazole and bismuth subsalicylate generally had an additive effect on inhibition of Helicobacter pylori growth.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

Ultrasonographic examination for lateral lymphatic spread and local recurrence of rectal cancer. Preoperative detection and evaluation.

PURPOSE: A preoperative evaluation of the lateral lymphatic spread is essential to decide the indication of autonomic nerve preserving operation for rectal cancer. For this evaluation, we used common ultrasonographic examination of the lower abdomen. We also performed this examination on postoperative patients in whom local recurrence had been suspected. Results and effectiveness of examination were evaluated. METHOD: First, we identified arteries in the pelvic cavity (common, external, and internal iliac arteries), and then we sought lymph nodes in the spaces between these arteries, urinary bladder, and rectum. RESULTS: We performed this examination on 40 preoperative patients with rectal cancer and could detect lymph nodes in 12 patients. By the size and features of these lymph nodes, five patients were considered lateral lymphatic spread-positive. After the operation, resected specimens revealed three patients were pathologically positive, and the two others were false-positive. Only one patient was false-negative. Total accuracy of the examination was 92.5 percent; however, the positive lymph node around middle rectal artery and obturator artery had been overlooked. We also performed this examination on postoperative patients in whom local recurrence had been suspected. In one postoperative patient, a recurrent lesion of 3.0 x 3.5 cm in size was detected along the right external iliac artery and could be resected by the retroperitoneal surgical approach. CONCLUSION: We consider this examination very effective for detecting lymph node metastasis preoperatively and recurrent lesions in the pelvic cavity.

Humans↗
PubMed1995

Inhibitory effect of methylmercury on migration and tube formation by cultured human vascular endothelial cells.

The effect of methylmercury chloride (MeHg) on migration and tube formation by cultured human umbilical vein endothelial cells (HUVECs) was quantitatively analyzed. The distance of endothelial cell outgrowth from the scraped edge of a monolayer was measured. HUVEC outgrowth was inhibited by MeHg (1.0-5.0 microM) treatment in a dose-dependent manner. Tube formation was studied by culturing the cells on gelled basement membrane matrix (Matrigel). Treatment of HUVECs with 0.1-5.0 microM MeHg for 24 h inhibited tube formation dose-dependently. These results suggest that migration and tube formation by HUVECs are susceptible to MeHg cytotoxicity, and that MeHg could be injurious to endothelial cell function, which may be involved in the pathogenesis of arteriosclerosis.

Arteriosclerosis↗
PubMed1995

Effect of lead on tube formation by cultured human vascular endothelial cells.

The effect of lead acetate (Pb) on the growth of and tube formation by cultured human umbilical vascular endothelial cells (HUVEC) was examined. HUVEC were collected by enzymatic digestion with collagenase. The number of viable cells of HUVEC was negligibly affected by cultivation with Pb at concentrations of 1-100 microM, but was slightly reduced by cultivation at 500 microM. Tube formation was studied by culturing the cells on a gelled basement membrane matrix (Matrigel). Treatment of HUVEC with 0.1-50.0 microM Pb for 24 h inhibited tube formation dose-dependently. The length of tube formation decreased time-dependently with 1.0 microM Pb. These findings suggest that Pb inhibits the formation of a capillary network by HUVEC, and that Pb could be injurious to endothelial cell function.

Cell Count↗
PubMed1995

Effects of radiotherapy on the cellular uptake of carbon-14 labeled L-methionine in tumor tissue.

In order to examine in vivo effects of irradiation on tumor uptake of L-[methyl-11C]methionine at a cellular level, the distribution of L-[methyl-14C]methionine (Met) in a rat AH109A tumor model was investigated using microautoradiography. Silver grain density of tumor cell layer decreased rapidly within the first day after 20 Gy of irradiation, and continued to fall during day 2. Grain density of granulation tissue was 25% of tumor cells and was unchanged after irradiation. Macrophages and necrotic tissue showed low grain density and a small post-irradiation decrease. One day after irradiation, tumor cell showed giant cell formation and decreased cell density per unit area. The number of grains was greater in giant tumor cells than in non-irradiated tumor cell. Rapid response of Met uptake by tumor cells without a significant uptake by granulation tissue and macrophages suggest that 11C-Met is a suitable tracer for monitoring tumor radiotherapy with positron emission tomography.

Animals↗
PubMed1995

Early gastric cancer: its surveillance and natural course.

The present status of screening for gastric cancer, and the natural course of the disease, are the concerns of this paper. The development of new diagnostic modalities has led to an increase in the percentage of early gastric cancers detected. Improvements in technology, and alterations in nutrient intake, are linked to the reduction in the mortality from gastric cancer that has taken place. Observation of the natural course of gastric cancer development shows that "early gastric cancer" is genuinely the early stage of gastric cancer, and not a term for a different disease phenomenon. A "malignant cycle" was shown to be implicated in the process of cancer development.

Endoscopy, Gastrointestinal↗
PubMed1995

p55 and p75 tumor necrosis factor receptor expression on human glioblastoma cells.

Expression of the two types of tumor necrosis factor (TNF) receptor, p55 and p75, in 12 human glioblastoma cell lines was studied. Reverse-transcription polymerase chain reaction detected messenger ribonucleic acid (mRNA) transcripts of p55 TNF receptor in all 12 cell lines tested, but p75 TNF receptor mRNA in only four cell lines. Flow cytometric analysis with anti-p55 and anti-p75 TNF receptor monoclonal antibodies demonstrated both p55 and p75 proteins in these four cell lines, but the level of expression of p75 molecule was very low. Correlation of p55 and p75 TNF receptor expression with TNF-induced growth suppression and production of bioactive molecules (interleukin-6, interleukin-8, manganase-superoxide dismutase, prostaglandin E2) showed that p55 TNF receptor mediates these TNF actions, but none of the responses were influenced by the presence of the p75 TNF receptor, which apparently has no specific role.

Base Sequence↗
PubMed1995

Nitric oxide synthase protects the heart against ischemia-reperfusion injury in rabbits.

The role of nitric oxide (NO) in myocardial ischemia-reperfusion injury is still controversial. To determine the role of NO in the propagation of myocardial injury in a coronary artery occlusion-reperfusion model, we examined the effect of a competitive NO synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), with and without L-arginine, on the size of the infarct resulting from coronary artery occlusion (30 min) followed by reperfusion (48 hr) in rabbits. L-NAME (300 micrograms/kg, as a bolus, and 100 micrograms/kg/min, i.v.) with and without L-arginine (30 mg/kg, as a bolus, and 10 mg/kg/min, i.v.) was administered immediately before coronary occlusion to 60 min after reperfusion. The infarct size in the L-NAME-treated rabbits (75.1% +/- 5.0%, n = 7), assessed as a percentage of infarcted region/ischemic region, was significantly larger than that of control rabbits (51.2% +/- 7.4%, n = 7; P < .05). The increase in infarct size was significantly attenuated by the treatment with L-NAME and L-arginine (62.0% +/- 4.0%, n = 7). However, the infarct size for the treatment with L-NAME and D-arginine (76.7% +/- 5.7%, n = 6) did not differ from that in the L-NAME-treated rabbits. There was no significant difference in the infarct size between L-arginine-treated (60.1% +/- 7.3%, n = 6) and control rabbits. Rate-pressure products, as an index of myocardial oxygen consumption, were comparable in all the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Oxidoreductases↗
PubMed1995

[A case of histological complete remission by preoperative intraarterial infusion chemotherapy].

We experienced a case of histological complete remission by preoperative intraarterial infusion chemotherapy in the treatment of histologically diagnosed endometrial cancer of well differentiated type. MRI demonstrated invasion of the myometrium to a depth of more than 1/2 and left partial parametrium. This patient was given intra-uterine arterial infusion chemotherapy twice (CDDP & ADM ia, CPA iv). Radical hysterectomy was done 3 weeks after intraarterial infusion chemotherapy. The extirpated uterus was histologically complete remission. Thus, in this case shows that intraarterial infusion chemotherapy is effective for neo-adjuvant chemotherapy of endometrial cancer.

Adenocarcinoma↗
PubMed1995

Assessment of production of endothelium-derived relaxing factor by cultured porcine cerebral microvessel endothelial cells.

To establish an experimental system to assess the production of endothelium-derived relaxing factor (EDRF) by cultured porcine cerebral microvessel endothelial cells (PCMEC), the effect of PCMEC on thrombin-induced platelet aggregation was studied. For the platelet aggregation cuvettes lined with PCMEC were used. The cuvettes were prepared by seeding PCMEC in gelatin-coated cuvettes at a cell density of 2 x 10(5) cells/ml and culturing for 48 hours. Thrombin-induced platelet aggregation was markedly inhibited in the presence of PCMEC. Indomethacin reduced the PCMEC-dependent anti-platelet aggregatory effect. This PCMEC-dependent anti-platelet aggregatory effect was increased by the addition of bradykinin which stimulates the production of EDRF. These findings suggest that this simple experimental system is useful in assessing the production of EDRF by PCMEC and in examining the effects of various chemicals (or agents) on EDRF production.

Animals↗
PubMed1995

Methionine uptake by tumor tissue: a microautoradiographic comparison with FDG.

UNLABELLED: L-methyl-11C-methionine (11C-Met) and 2-deoxy-2-18F-fluoro-D-glucose (18F-FDG) are used for tumor diagnosis and treatment evaluation by PET. In order to examine the role of these tracers in cancer imaging, intratumoral properties of 14C-Met were studied and compared to those of 18F-FDG. METHODS: The distribution of 14C-Met in various cellular elements of two different mouse malignant tumor tissues, MH134 and FM3A, was analyzed serially using microautoradiography within a period of 120 min after injection of the tracer. RESULTS: Carbon-14-Met and 18F-FDG showed different distributions in tumor tissue. Carbon-14-Met uptake by the tumor was mostly by viable cancer cells. The uptake by macrophages and other cellular components was low. The uptake was higher in the highly proliferative tumor but did not reflect protein synthesis. The rapid and slow growing tumors demonstrated that 14C-Met uptake ratio was lower than that of 18F-FDG, reflecting de novo DNA synthesis ratio. CONCLUSION: Carbon-14-Met uptake represents the presence of viable cancer cells. Carbon-11-Met may be suitable for treatment evaluation of individual tumors but not growth rates of different tumors. Fluorine-18-FDG reflects tumor-host immune system reaction and is an excellent tool for pretreatment evaluation of tumors and determination of tumor proliferative activity.

Animals↗
PubMed1995

Endoscopic ultrasonography in inflammatory bowel diseases.

Endoscopic ultrasound (EUS) was designed for the evaluation of malignancies; however, its utility has been extended to the assessment of benign disorders, which include inflammatory bowel diseases. Topics discussed in this article include instruments and methods, EUS images in various inflammatory diseases, clinical severity and EUS typing, endoscopic grading of inflammation and EUS typing, extent of disease involvement and EUS typing, response to therapy and EUS typing, changes in EUS findings by treatment, Crohn's disease, radiation proctitis, ischemic colitis, tuberculosis, and mucosal prolapse syndrome.

Colitis, Ischemic↗
PubMed1994

Cloning of an isoform of mouse TGF-beta type II receptor gene.

A variant of transforming growth factor-beta type II receptor (TGF-beta RII) cDNA was isolated from a mouse brain cDNA library. The predicted receptor is identical to previously reported mouse TGF-beta RII except that the isoform has an insertion sequence of 25 amino acids in the predicted ligand-binding domain. By the use of reverse transcription-polymerase chain reaction (RT-PCR), transcripts for both isoforms were detected in all tissues and developing embryos examined. The isoform transiently expressed in COS cells showed a similar ligand-binding specificity to authentic TGF-beta RII. These results suggest that the mouse TGF-beta RII gene generates multiple isoforms, possibly by alternative splicing, as reported for activin type IIB receptor; and an isoform which has the extra sequence in the ligand-binding domain is also involved in the TGF-beta signal transduction.

Alternative Splicing↗