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H Oyamada

Publications and source records attributed to H Oyamada.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Chemoembolization with degradable starch microspheres for liver metastases of colorectal cancer].

Transcatheter chemoembolization using degradable starch microspheres (DSM) was performed in 17 patients with liver metastases of colorectal cancer. DSM, 45 microns in diameter, which are easily degraded by serum amylase, and therefore obstruct arterial blood flow temporarily at the arteriolar capillary bed. DSM mixed with mitomycin C were administered through the catheter introduced by Seldinger's method in 13 cases, and through subcutaneously implanted drug delivery system (Port-A-Cath) in 4 cases. The treatment was repeated 5 times on the average at intervals of 2 to 4 weeks. The therapeutic effect of this chemoembolization was evaluated by the change in tumor size measured by angiography or computed tomography. Tumor regression of over 50% was observed in 9 of 17 cases (53%). Elevated serum CEA levels (greater than 10 ng/ml) decreased in 10 of 15 cases (67%). One-year survival rate was 48% in 17 cases, and among them it was 100% in 7 cases with the extent of several liver metastases (H2). Extrahepatic metastasis was observed in 3 of 17 cases (18%) before the treatment, and in 8 cases (47%) after the treatment. Abdominal pain occurred in 36% of the cases by the administration of DSM, but the pain disappeared within 2 hours. No major side effects such as bone marrow suppression or hepatotoxicity were observed. Our results suggest that chemoembolization using DSM is effective and safe in the treatment of liver metastases from colorectal cancer.

Carcinoembryonic Antigen↗
PubMed1990

Mammary tumor immunoscintigraphy in rats: the use of 131I-anti-estriol 3-sulfate antibody.

The scintigraphic imaging of mammary tumors with anti-estriol 3-sulfate (E3 3-S) antibody was studied in rats. A chemical carcinogen, 7,12-dimethylbenz(a)anthracine (DMBA), induced mammary tumors in Sprague-Dawley female rats. Highly specific anti-E3 3-S antibody was prepared and radioiodinated by [131I]NaI using the chloramine-T method. At 24 h after administration of 131I-anti-E3 3-S antibody, goat anti-guinea pig immunogloblin G (IgG) was injected as the second antibody (SA) and nuclear scintigraphy was performed. Mammary tumors were clearly visualized following SA injection.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1990

Role of oxygen-derived free radicals in the pathogenesis of gastric mucosal lesions in rats.

The role of oxygen-derived free radicals and lipid peroxidation in the pathogenesis of acute gastric mucosal erosion was investigated in rat models produced by burn shock stress, by treatment with regional hyperthermia, platelet activating factor, and compound 48/80, and by ischemia-reperfusion. In all experimental models, the increase in the gastric erosions and in TBA reactants in the gastric mucosa were significantly inhibited by the treatment with superoxide dismutase (SOD) and/or catalase. Pretreatment with allopurinol, a competitive inhibitor of xanthine oxidase, prevented considerably the gastric injury (a) induced by burn shock, (b) produced by treatment with compound 48/80, and (c) caused by ischemia-reperfusion. By the treatment with anti-rat neutrophil antibody, the gastric mucosal injuries induced by regional hyperthermia, platelet activating factor, and compound 48/80 were significantly inhibited; however, burn shock and ischemia-reperfusion injuries were not inhibited. These results suggest that oxygen-free radical and lipid peroxidation contribute to the formation of gastric mucosal lesions, and that the sources of oxygen radicals seem to be different among these experimental models.

Allopurinol↗
PubMed1990

[Role of active oxygen species and lipid peroxidation in liver injury induced by ischemia-reperfusion].

The role of superoxide and lipid peroxidation in liver injury induced by ischemia-reperfusion was investigated in rats. Ischemic condition of the liver was created by applying small clamps to the right branch of portal vein and the right hepatic artery for 15 min. Clamping of hepatic artery and portal vein could decrease the hepatic blood flow to about 30% of that measured before the clamping. Levels of serum GPT and thiobarbituric acid (TBA) reactive substances in the liver tissue were significantly increased 30 min after the reperfusion following 15 min of ischemia. The increase in serum GPT and TBA reactants in the liver tissue was significantly inhibited by the treatment with superoxide dismutase combined with catalase. The treatment with allopurinol significantly inhibited the elevation of serum GPT levels and showed a tendency to inhibit the increase in TBA reactants in liver tissue. These results suggest that active oxygen species and lipid peroxidation may play an important role in the pathogenesis of ischemia-reperfusion injury in the liver, and hypoxanthine-xanthine oxidase system may be one of the main sources of active oxygen species.

Animals↗
PubMed1990

[Role of free radicals and lipid peroxidation in gastric mucosal injury induced by ischemia-reperfusion in rats].

Ischemia and reperfusion is of the greatest importance in the pathology of various diseases. This study was designed to investigate the role of oxygen-derived free radicals and lipid peroxidation in gastric mucosal injury induced by ischemia-reperfusion in rats. Clamping of the celiac artery in rats reduced the gastric mucosal blood flow to 10% of that measured before the clamping. Gastric mucosal injury, such as spotty and linear hemorrhagic erosions, was seen in rats 60 min of the reperfusion following 30 min of ischemia. Thiobarbituric acid (TBA) reactants in the gastric mucosa were increased after the reperfusion. The increase in gastric mucosal lesions and TBA reactants were significantly inhibited by the treatment with SOD+ catalase and allopurinol. These results suggest that oxygen-derived free radicals and lipid peroxidation may play an important role in the pathogenesis of acute gastric mucosal lesions induced by ischemia-reperfusion.

Animals↗
PubMed1989

[Antitumor effect and indication of chemoembolization using degradable starch microspheres and regional hyperthermia in patients with hepatocellular carcinoma].

Antitumor effects and indications of chemoembolization using degradable starch microspheres (DSM) and regional hyperthermia were investigated in patients with unresectable hepatocellular carcinoma. Chemoembolization using DSM was performed in 40 cases and fourteen cases were treated with the combination of hyperthermia. Tumor regression rate over 50% was 48% (chemoembolization alone: 42%, combined hyperthermia: 57%). Though one and two year survival rates were 62% and 54% respectively in the treatment with chemoembolization alone, one year survival rate was 91% in the treatment with combined hyperthermia. From the viewpoint of antitumor effect, it was thought that effectual indications of chemoembolization using DSM alone were the cases whose tumor size were below 7 cm and portal invasion were negative. These indications however were spread by the combination of hyperthermia. The DSM, temporary embolus, is suitable for combination of hyperthermia because chemoembolization using DSM can be performed many times. The cases with clinical stage III and obstruction of the first branch of portal veins did not become severe hepatic failure because DSM was temporary embolus. Therefore, from the viewpoint of safety, chemoembolization using DSM has almost the same indications as intra-arterial infusion therapy. These results suggested that chemoembolization using DSM will be a beneficial methods as combination therapy for unresectable hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1989

Molecular identification of a novel human rotavirus in relation to subgroup and electropherotype of genomic RNA.

A total of 41 stool rotavirus specimens collected from children with acute diarrhea at four different locations in Akita Prefecture, Japan, during the peak of the winter diarrhea epidemic in 1988 were analyzed by polyacrylamide gel electrophoresis of viral RNA in conjunction with subgrouping assay. We found that a single strain predominated, with cocirculating strains with less common electropherotypes at a given location, and that two different strains could predominate at geographically close but different locations even during a very limited time of the epidemic season. Furthermore, we isolated a human rotavirus strain (AU125) that was similar to the AU-1 strain in that it possessed a long RNA pattern yet belonged to subgroup I. Genetic analysis by RNA-RNA hybridization assay indicated that the AU125 strain was distinct from two previously identified human rotavirus gene groups (genogroups) represented by the Wa strain (subgroup II with long RNA electropherotype) and the DS-1 strain (subgroup I with short RNA electropherotype), but was very closely related to the AU-1 strain. These data suggest that the genetic diversity of human rotaviruses may be more extensive than was previously thought.

Child↗
PubMed1989

Loading of fura-2/AM with an aid of DFP on single smooth muscle cells prepared from guinea pig taenia coli.

Procedures for loading fura 2 acetoxymethyl ester (fura 2/AM) into smooth muscle cells isolated from guinea pig taenia coli have been investigated. It was difficult to load these cells with fura 2 in the absence of diisopropylfluorophosphate (DFP). The presence of DFP, a potent cholinesterase (ChE) inhibitor during the loading, significantly enhanced the incorporation of the fura 2 into the cells. More than 80% of the single cells treated with DFP and fura 2/AM were viable. DFP did not affect the ability of the cell to shorten in response to either Ca2+ or carbachol (CCh). The single cells contracted transiently with caffeine and the intracellular Ca2+ concentration increased simultaneously. The results indicate that the amount of fura 2/AM incorporated into the single smooth muscle cells depends on the activity of ChE or various serine proteases located outside the cells and suppression of these enzymes induces more efficient incorporation, which permits shorter incorporation periods. Since the presence of DFP may shorten the incubation time significantly, the viability of these cells is improved. The procedure might be applicable for measuring simultaneously the contraction of cells and the behavior of intracellular Ca2+ in the same cells.

Animals↗
PubMed1989

Use of alkaline northern blot hybridization for the identification of genetic relatedness of the fourth gene of rotaviruses.

A recently developed alkaline northern blot hybridization assay (Li, J. K. K., Parker, B. & Kowalik, T., Analytical Biochemistry 163, 210-18, 1987) was used to assess the genetic relatedness of the fourth gene of human rotavirus strains recovered from children with diarrhea and from asymptomatic neonates. Genomic double stranded (ds) RNAs of the rotavirus strains were separated by polyacrylamide gel electrophoresis and were blotted to nylon membranes (Gene Screen Plus or Zeta Probe membranes). The blotted RNAs were then probed with 32P-labelled single-stranded (ss) RNA probes prepared by in vitro transcription from single-shelled particles of the different strains. When analysed under a condition of high stringency (52 degrees C, 2.5 x SSC, 50% formamide) that allowed up to 21% of nucleotide mismatch, a high degree of the fourth gene homology was observed among strains recovered from asymptomatic neonates (asymptomatic rotaviruses) or among strains recovered from infants and children with diarrhea (symptomatic rotaviruses), while the homology of the fourth gene between the asymptomatic and symptomatic strains was considerably lower. It is of particular interest that the fourth gene of the AU-1 and AU228 strains recovered from children with diarrhea failed to hybridize to the corresponding gene of either asymptomatic or symptomatic rotavirus strains but showed a high degree of homology with the fourth gene of a feline rotavirus recovered from an apparently healthy cat. These data indicate that a new group of the fourth gene is present among symptomatic rotaviruses and that the fourth gene of this group is genetically related to the corresponding gene of a feline rotavirus.

Animals↗
PubMed1989

Identification of rotaviruses by dot-blot hybridization using an alkaline phosphatase-conjugated synthetic oligonucleotide probe.

We have evaluated a recently-developed dot-blot hybridization assay for the detection of human rotaviruses using an alkaline-phosphatase conjugated oligonucleotide probe. The lower detection limit of this assay was 1 ng (approximately 5 x 10(7) copies) of the double-stranded (ds) RNA, when a purified preparation from serotype 1 human rotavirus was used but appeared to be much higher when applied on clinical specimens. This assay could detect dsRNA from rotavirus strains belonging to serotypes 1 through 6, 8 and 9. A total of 235 stool specimens were used to evaluate the oligonucleotide probe assay in comparison with polyacrylamide gel electrophoresis and latex agglutination assay (Rotalex). When polyacrylamide gel electrophoresis was used as a gold standard, sensitivity, specificity and positive and negative predictive values of the probe assay were 84, 100, 100 and 89%, respectively. These values were slightly better than those of Rotalex assay which is commonly used in clinical laboratories in Japan. Although the probe assay requires more hands-on time than the immunoassays, the high specificity of this probe assay recommends it as a confirmatory test in the clinical laboratory setting.

Alkaline Phosphatase↗
PubMed1989

Role of free radicals and lipid peroxidation in gastric mucosal injury induced by ischemia-reperfusion in rats.

Ischemia and reperfusion are of the greatest importance in the pathology of many diseases. We investigated the roles of oxygen-derived free radicals and lipid peroxidation in gastric mucosal injury, such as spotty and linear hemorrhagic erosions, induced in rats by ischemia-reperfusion. The gastric mucosal injury and the increase in thiobarbituric acid (TBA) reactants in the gastric mucosa induced by ischemia-reperfusion were significantly inhibited by treatment with SOD and catalase. These results suggest that oxygen-derived free radicals and lipid peroxidation play important roles in the pathogenesis of acute gastric mucosal lesions induced by ischemia-reperfusion.

Animals↗
PubMed1989

Pathogenesis of platelet-activating factor-induced gastric mucosal damage in rats.

Platelet-activating factor (PAF), given intravenously, induced erosions and hyperemia to the rats stomachs. Gastric mucosal blood flow was decreased and thiobarbituric acid (TBA) reactants (an index of lipid peroxidation) in the gastric mucosa were increased 10 min after PAF injection. Superoxide dismutase plus catalase reduced the gastric mucosal lesions and TBA reactants, but had no influence on gastric mucosal blood flow. A reduction in the number of circulating polymorphonuclear leukocytes (PMN) reduced the gastric mucosal damage and TBA reactants, and inhibited the decrease in gastric mucosal blood flow, as observed 30 and 60 min after PAF injection. PAF induced superoxide production by rat PMN and enhanced that stimulated by opsonized zymosan or phorbol myristate acetate. These results suggest that microcirculatory disturbance and oxygen-derived free radicals generated by PMN play important roles in gastric mucosal lesions induced by PAF.

Animals↗
PubMed1989

Role of oxygen-derived free radicals in gastric mucosal injury induced by ischemia or ischemia-reperfusion in rats.

Oxygen-derived free radicals have been implicated as possible mediators in the development of tissue injury induced by ischemia and reperfusion. Clamping of the celiac artery in rats reduced the gastric mucosal blood flow to 10% of that measured before the clamping. The area of gastric erosions and thiobarbituric acid (TBA) reactants in gastric mucosa were significantly increased 60 and 90 min after clamping. These changes were inhibited by treatment with SOD and catalase. Thirty and 60 min after reoxygenation. produced by removal of the clamps following 30 min of ischemia, gastric mucosal injury and the increase in TBA reactants were markedly aggravated compared with those induced by ischemia alone. SOD and catalase significantly inhibited these changes. The serum alpha-tocopherol/cholesterol ratio, an index of in vivo lipid peroxidation, was significantly decreased after long periods of ischemia (60 and 90 min), or after 30 and 60 min of reperfusion following 30 min of ischemia. These results indicated that active oxygen species and lipid peroxidation may play a role in the pathogenesis of gastric mucosal injury induced by both ischemia alone and ischemia-reperfusion. Although, allopurinol inhibited the formation of gastric mucosal injury and the increase in TBA reactants in gastric mucosa, the depletion of polymorphonuclear leukocytes (PMN) counts induced by an injection of anti-rat PMN antibody did not inhibit these changes. As compared with the hypoxanthine-xanthine oxidase system. PMN seem to play a relatively small part in the formation of gastric mucosal injury induced by ischemia-reperfusion.

Allopurinol↗