Search PubMed⌕ Search

Biomedical subjects

H Suda

Publications and source records attributed to H Suda.

At least 217 records · Page 12Linked to original sources
PubMed1991

An endothelin receptor (ETA) antagonist isolated from Streptomyces misakiensis.

A competitive endothelin (ET) antagonist, BE-18257B, was isolated from the fermentation products of Streptomyces misakiensis. It is a novel cyclic pentapeptide, cyclo(-D-Glu-L-Ala-allo-D-Ile-L-Leu-D-Trp-), and binds to ETA receptors (ET-1 selective) in cardiovascular tissues, but not to ETB receptors (equally sensitive to isopeptides of ET family) in kidney, adrenal gland and cerebellum tissues. BE-18257B also antagonizes ET-1-induced vasoconstriction in rabbit iliac artery and pressor action in rats. Thus it is a selective ETA antagonist and should provide a valuable tool for elucidation of the pharmacological and pathophysiological roles of ET-1.

Animals↗
PubMed1991

[Intraarterial infusion of hypoxic radiosensitizer RK28 in rabbit VX2 tumor system].

The effect of regional intra-arterial infusion of a hypoxic cell radiosensitizer RK28 (2-nitro-imidazole nucleoside analogue) on rabbit VX2 tumor was evaluated. Rabbits each weighing 2.5-3 kg were implanted with VX2 tumor in the left hind legs. Solid tumors grown up to 3 cm in diameter were treated with X-ray irradiation. Tumor volumes were assayed weekly by computed tomography (CT). Six rabbits were treated with 15 Gy of X-ray irradiation alone, and the other six rabbits were treated with intra-arterial infusion of RK28 (80 mg/kg) two minutes before 15 Gy of irradiation. The latter tumors regressed more rapidly than the former (p less than 0.01), and the latter rabbits seemed to survive longer than the former. The pharmacokinetics of RK28 and its metabolites in tumor tissue and serum were measured by high performance liquid chromatography (HPLC) using six rabbits. During irradiation, a high concentration of the agent was achieved in tumor tissue. It is suggested that a successful radiosensitizing effect will be obtained when regional intra-arterial infusion of RK28 is clinically combined with intraoperative radiation therapy and brachytherapy.

Animals↗
PubMed1991

Establishment of a new perchloric acid treatment method to allow determination of the total endotoxin content in human plasma by the limulus test and clinical application.

We established a new method of plasma treatment for the removal of interfering factors in the plasma to allow detection of endotoxin by limulus test. The limulus test used was an endotoxin-specific chromogenic test, the Endospecy test. Perchloric acid (PCA) treatment and centrifugation (PCA method) is usually used to remove interfering factors from plasma, with the precipitate being discarded and the supernatant used to detect endotoxin. As the solubilized precipitates of endotoxin-spiked plasma and some patient plasma were found to contain the Endospecy activity, we have devised a new method assaying endotoxin in both the supernatant and precipitate. This study confirmed that the solubilized precipitate of endotoxin-spiked plasma had Endospecy activity and found that the precipitate had other endotoxin activities, such as lethality in galactosamine-sensitized mice and pyrogenicity in rabbits. We also confirmed that interfering factors were completely removed from plasma samples by this new method. The endotoxin level after the new PCA method was found to be about 8 times higher than that determined after PCA treatment and the new PCA method surpasses the conventional PCA method with regard to the positive rate of endotoxin contents in clinical samples. These results indicate that the new PCA method is superior to the PCA method as a plasma pretreatment method for limulus test.

Amidohydrolases↗
PubMed1991

Effect of tranilast on endothelin-induced bronchoconstriction in guinea pigs.

Tranilast, an anti-asthmatic drug with anti-allergic properties, inhibited endothelin (ET)-induced asthmatic like respiratory obstruction in guinea pigs when administered orally at 200 mg/kg 1 h prior to the intravenous injection of ET. ET also caused a bronchoconstriction detected as an increase in inflation pressure in Konzett-Rössler apparatus. Tranilast (200 mg/kg, p.o. 1 h before ET) inhibited ET-induced increased inflation pressure. ET-induced bronchoconstriction detected as an increase in inflation pressure was clearly inhibited by the administration of indomethacin (used as a reference drug) at doses of 1 and 5 mg/kg 30 min prior to onset of the reaction. In addition to the above in vivo experiments, tranilast at concentrations between 10(-5) and 10(-4) g/ml inhibited ET-induced contraction of isolated guinea pig tracheal muscle, whereas indomethacin did not affect this in vitro response. In order to elucidate the inhibitory mechanism of tranilast on ET-induced bronchoconstriction, the effects in Ca(2+)-free medium and on ET-induced histamine and prostaglandin F2 alpha release from tracheal muscle were investigated. Consequently, tranilast did not affect ET-induced contraction of guinea pig tracheal muscle in Ca(2+)-free Tyrode's solution and ET induced neither histamine nor PGF2 alpha release. These results suggest that tranilast inhibits ET-induced bronchoconstriction by inhibiting the ET-induced calcium influx into tracheal muscle.

Animals↗
PubMed1991

Evaluation of left ventricular early diastolic function after coronary artery bypass grafting relating to myocardial damage.

This clinical study was undertaken to evaluate resting left ventricular early diastolic function relating to perioperative myocardial damage after coronary artery bypass graft (CABG) with radionuclide ventriculography. Forty-eight cases undergoing CABG were divided into two groups--Group I: not complicated with perioperative myocardial infarction (PMI), and Group II: complicated with PMI. In group I (42 cases), early diastolic parameters such as peak filling rate (1/3 PFR) and mean filling rate (1/3 FR(m)) during first third diastole were not impaired in the postoperative and follow up periods. In contrast, in Group II (6 cases), early diastolic parameters were significantly decreased to 157 +/- 74% EDV/sec of 1/3 PFR(pre op: 234 +/- 74, p less than 0.05) and 153 +/- 80% EVD/sec of 1/3 FR(m) (pre op: 231 +/- 86, p less than 0.05) in the postoperative period, and these parameters were still decreased in follow up period. The time to peak filling rate, normalized to diastolic time (TPFR/DT) of Group II cases, was severely prolonged in both periods. From these results, the complication of perioperative myocardial infarction was suggested by the decrease of early diastolic function and the prolongation of the time to peak filling rate. Early diastolic function was a more sensitive parameter than systolic function in the detection of impaired cardiac function in those cases with perioperative myocardial damage after CABG.

Adult↗
PubMed1991

Effect of three novel K+ channel openers, cromakalim, pinacidil and nicorandil on allergic reaction and experimental asthma.

The anti-allergic and anti-asthmatic activities of three potassium (K+) channel openers, cromakalim, pinacidil, and nicorandil, were investigated. 1) Forty-eight-hour homologous passive cutaneous anaphylaxis (PCA) in mice was not affected by cromakalim, pinacidil, or nicorandil. Ketotifen significantly inhibited the reaction. 2) Antigen-induced histamine release from sensitized guinea pig lung tissue was not affected by cromakalim, pinacidil or nicorandil (except for 10(-4) M nicorandil). Salbutamol inhibited the release of histamine. 3) Histamine, serotonin and LTC4-induced vasculitis in rat back skin was not affected by any of these three K+ channel openers. 4) Antigen-induced constriction of isolated sensitized guinea pig tracheal muscle was relaxed by each of the K+ channel openers. 5) Constrictions of isolated guinea pig tracheal muscle caused by high potassium, histamine, LTC4, or U-46619 were clearly relaxed by each of the three K+ channel openers. 6) Increases of airway resistance caused by histamine, LTD4, or U-46619 in guinea pigs in vivo were inhibited by administration of each of the three K+ channel openers. 7) Experimental asthma caused by the IgE antibody and antigen system in guinea pigs was inhibited by each of the three K+ channel openers.

Airway Resistance↗
PubMed1991

[Statistical study of endodontically treated teeth by undergraduate students from 1979 to 1989].

In clinical education in dentistry, it is very important and significant that the undergraduate students themselves treat the patients. According to the rapid progress of dental science, the complexity and the high degree of the quality of education increase more and more, so that it is a requisite to make our efforts to enrich the quality of the practice at all times. In this paper, we investigated and statistically analyzed the result of 3,359 cases (test cases: 304, general cases: 3,055) which were treated endodontically by the undergraduate students of Tokyo Medical and Dental University in the four classes of 1979, 1982, 1986 and 1989. Both the number of the treated cases and the patients decreased year by year. Only the patients above sixty years old showed a tendency to increase in number. The result of the test cases was not always representative of the result of the general cases. If the clinical instructors for the undergraduate students grasp the detailed results of this study, we can expect that they can guide and train the undergraduate students more effectively.

Adult↗
PubMed1991

[Response properties of pulpal nerve fibers with different conduction velocities].

Tapering and branching of the nerve fibers cause the conduction velocity (CV) along the axon to be unequal. The purpose of this study was to investigate the response properties of the myelinated and unmyelinated nerve fibers in the cat tooth pulp. Electrophysiological recordings were made from the functional single fibers innervating the lower canine tooth pulp in 25 adult cats anesthetized with pentobarbital sodium after the application of four types of stimuli to the canine tooth. A total of 272 single pulpal nerve fibers was identified. A-fibers (n = 215) were divided into two groups: One (Ac, n = 55) consisting of the fibers whose intrapulpal CVs were less than 2 m/s and the extra-pulpal CVs of more than 2 m/s, and the other (At, n = 160) consisting of the fibers whose CVs were more than 2m/s both inside and outside the tooth pulp. Fifty-seven C-fibers (C) were also found. None of C, 47% of At and 46% of Ac responded to the rapid elevation of the temperature. None of At, 38% of Ac and 53% of C responded to the continuous heat. None of C, 20% of At and 20% of Ac responded to the hydrostatic pressure. None of At, 86% of Ac and all of C responded to bradykinin. These results suggest that the functional difference between the pulpal A-and C-fibers is not clear and that the Ac-fibers may complicate the dental and pulpal pain.

Animals↗
PubMed1991

New antitumor substances, BE-12406A and BE-12406B, produced by a streptomycete. I. Taxonomy, fermentation, isolation, physico-chemical and biological properties.

New antitumor substances, designated BE-12406A and BE-12406B, were isolated from the culture broth of a streptomycete, strain BA 12406. The active principles were extracted from mycelium by methanol and successively purified by silica gel column chromatography and preparative TLC. BE-12406A and BE-12406B inhibited the growth of vincristine-resistant or doxorubicin-resistant P388 murine leukemia cell lines as well as their parent sensitive cell line. In in vivo experiments, BE-12406A inhibited the growth of S-180 murine ascites tumor.

Aminoglycosides↗
PubMed1991

New antitumor substances, BE-12406A and BE-12406B, produced by a streptomycete. II. Structure determination.

The structure of BE-12406A and BE-12406B, which were isolated from the culture broth of a streptomycete as antitumor substances, were determined by means of spectral analyses and chemical studies. The structure of BE-12406A is 1-hydroxy-10-methoxy-8-methyl-12-alpha- L-rhamnopyranosyloxy-6H-benzo[d]naphtho[1,2-b]pyran-6-one, and that of BE-12406B is 1,10-dihydroxy-8-methyl-12-alpha-L-rhamnopyranosyloxy-6H- benzo[d]naphtho[1,2-b]pyran-6-one.

Aminoglycosides↗
PubMed1991

Endothelin-binding inhibitors, BE-18257A and BE-18257B II. Structure determination.

The structures of novel endothelin-binding inhibitors, BE-18257A and BE-18257B, were elucidated by spectral analyses and chemical studies. Both inhibitors were found to have a cyclic pentapeptide structure containing three D-form amino acid residues, namely, the structures of BE-18257A and BE-18257B were elucidated to be cyclo(-D-Glu-L-Ala-D-Val-L-Leu-D-Trp-) and cyclo(-D-Glu-L-Ala-allo-D-Ile-L-Leu-D-Trp-), respectively.

Endothelins↗
PubMed1991

A new topoisomerase-II inhibitor, BE-10988, produced by a streptomycete. I. Taxonomy, fermentation, isolation and characterization.

A new topoisomerase inhibitor, BE-10988, was isolated from the culture broth of a strain of actinomycetes. The producing strain had a close resemblance to Streptomyces fimicarius and Streptomyces xanthocidicus. The active principle was extracted from the whole broth of strain BA10988 with ethyl acetate and purified by silica gel chromatography and by HPLC. BE-10988 increased DNA-topoisomerase complex formation and inhibited the growth of both doxorubicin-resistant and vincristine-resistant P388 murine leukemia cell lines, as well as sensitive P388 cell lines.

Animals↗
PubMed1991

A new antitumor substance BE-13793C, produced by a streptomycete. Taxonomy, fermentation, isolation, structure determination and biological activity.

A new antitumor substance, BE-13793C, which has topoisomerase inhibitory activity was isolated from the culture broth of a strain of actinomycetes. The producing strain, BA13793, isolated from a soil sample collected in Seto, Aichi Prefecture, Japan, has a resemblance to Streptoverticillium mobaraense. The active principle was extracted from the mycelium of strain BA13793 with methanol and purified by Sephadex LH-20 column chromatography. BE-13793C showed strong inhibitory activity against topoisomerases I and II and inhibited the growth of doxorubicin-resistant or vincristine-resistant P388 murine leukemia cell lines, as well as their parent P388 cell line.

Animals↗
PubMed1991

[Marfan's syndrome with annulo-aortic ectasia and ruptured mitral chorda--a case report of combined composite valve graft replacement of the aortic root and mitral valve replacement].

We report a case of Marfan's syndrome with acute heart failure caused by a ruptured mitral chorda that was successfully treated by one operation of combined composite valve graft replacement of aortic root and mitral valve replacement (MVR). A 23-year-old man was admitted to our hospital presenting severe dyspnea and chest pain. Echocardiography and cardiac catheterization studies demonstrated marked annulo-aortic ectasia, aortic regurgitation and significant mitral regurgitation due to a ruptured chorda. In operation, it was found that a chorda of the mitral posterior leaflet had been torn, with the leaflet completely prolapsed to the left atrium, and that the aortic root was dilated to 90 mm in diameter. The ascending aorta was extensively resected leaving those areas of aortic tissue involving the coronary ostia. Then the mobilized coronary arteries were reattached to the composite graft. MVR was performed with preservation of the whole anterior and posterior mitral valve apparatus except for that small part with the torn chorda. Histopathological findings of the aortic wall and mitral valve were compatible with those of Marfan's syndrome.

Adult↗
PubMed1991

[A case of surgical treatment of Budd-Chiari syndrome].

A 37-year-old man was admitted to our hospital for evaluation and surgical treatment of Budd-Chiari syndrome. He underwent a radical operation (endovenectomy and patch dilatation) with femoro-femoral assist bypass. The inferior vena cava (IVC) showed narrowing just below the diaphragm, and its lumen was completely obliterated with fibrous tissue. The fibrous strand was partially resected, and the IVC was closed by Xeno-medica pericardial patch. The patient has been doing well after the operation.

Adult↗
PubMed1991

[Clinical evaluation of bronchial artery infusion (BAI) in lung cancer].

Clinical evaluation of 32 cases of primary lung cancer treated with Bronchial Artery Infusion (BAI) were reported. As to the relationship between Bronchial Arteriogram (BAG) and therapeutic effect of BAI, the therapeutic effect of BAI was closely correlated with the degree of neovascularity. And as no correlation was shown between therapeutic effect and histology of lung cancer, the degree of neovascularity on BAG seemed to be more important factor. From the aspect of survival, neovascularity and B-P shunt on BAG showed no correlation with the survival time. On the relationship between survival and histology of lung cancer, squamous cell carcinoma and adenocarcinoma showed almost an equivalent survival. According to the stage of our cases, 25 out of 32 cases were stage III and IV, and they showed relatively better survival, especially stage III, of which MST was 16.6 months, and of which a two year survival rate was 33.5% considering MST and a two year survival rate of stage III A (N2) of non-resected non-small cell lung cancer in other reports are about 12 months and 20%, respectively. BAI is considered to be an effective method among several treatments against lung cancer.

Antineoplastic Combined Chemotherapy Protocols↗