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Biomedical subjects

M Ezaki

Publications and source records attributed to M Ezaki.

At least 37 records · Page 2Linked to original sources
PubMed1992

WS009 A and B, new endothelin receptor antagonists isolated from Streptomyces sp. no. 89009. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activities.

WS009 A and B novel endothelin receptor antagonists, have been isolated from the fermentation broth of Streptomyces sp. No. 89009. These antagonists were purified from the culture filtrate followed by Diaion SP-207, DEAE Toyopearl column chromatography and HPLC. WS009 A and B showed selective activity in an endothelin receptor binding assay with IC50 of 5.8 x 10(-6) M and 6.7 x 10(-7) M, respectively. On the basis of spectroscopic and chemical evidence, the structures of WS009 A and B have been established as 1 and 3, and are highly hydroxylated benz[a]anthraquinone chromophores.

Anthraquinones↗
PubMed1992

WS9326A, a novel tachykinin antagonist isolated from Streptomyces violaceusniger no. 9326. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activities.

Data from several studies suggest that tachykinins may play an important role in the pathophysiology of airway diseases, especially asthma. Our aim is to discover tachykinin antagonists which exhibit therapeutically useful anti-asthmatic activity. In our search for activities inhibiting the binding of [3H]substance P to guinea-pig lung membrane preparations, we have found that the fermentation product, WS9326A, isolated from Streptomyces violaceusniger, is a potent tachykinin receptor antagonist.

Animals↗
PubMed1992

WS-7338, new endothelin receptor antagonists isolated from Streptomyces sp. No. 7338. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activities.

WS-7338 A, B, C and D, novel endothelin receptor antagonists, have been isolated from fermentation broth of Streptomyces sp. No. 7338. These antagonists were purified from the culture mycelium by extraction with acetone, followed by carbon column chromatography and HPLC. Among them, WS-7338 B showed good activity in an endothelin receptor binding assay with an IC50 of 2.7 x 10(-7) M.

Amino Acid Sequence↗
PubMed1991

Locomotor system assessment by muscle magnetic resonance imaging.

Clinical evaluation of the locomotor system has long been hampered by difficulty in assessing the morphologic and functional integrity of skeletal muscles. Diagnostic imaging represents a major advance in the diagnosis and management of patients with locomotor dysfunction through the possibility of probing beyond overlying soft tissues to identify muscle lesions, determine their extent, characterize their composition, direct invasive procedures, and monitor therapies. Magnetic resonance imaging (MRI) appears to be the most promising of available imaging methods, because of its great sensitivity to changes in muscle water distribution and fat content. Also, it can distinguish between individual deep and superficial muscles. Serial evaluations of many muscles are practical because of the safety of MRI. While the cost effectiveness in the workup of locomotor dysfunction remains to be determined, the scientific and practical clinical information now available merits further investigation by clinicians and radiologists alike. The purpose of this review is to describe the potential role of skeletal muscle MRI in evaluating the locomotor system.

Humans↗
PubMed1990

Establishment and characterization of human pancreatic cancer cell lines in tissue culture and in nude mice.

Three human pancreatic cancer cell lines, designated as KP-1N, KP-2 and KP-3 have been established in both tissue cultures and in nude mice. The KP-1N and KP-3 tumors were obtained from liver metastases of pancreatic tumors and the KP-2 tumors was of primary pancreatic origin. The patients' tumors from which KP-1N and KP-2 were derived showed characteristics of adenocarcinoma, and the KP-3 tumor had adenosquamous carcinoma characteristics. Inoculations of samples from surgical specimens into athymic nude mice resulted in tumor formation, with the tumors histologically closely resembling the original neoplasms. Subcutaneous injections of the established cell lines also induced tumor formation and the tumors histologically resembled the original lesion in the cases of KP-2 and KP-3 tumors, but the KP-1N tumors in the mice were histologically different from the surgical specimen. The KP-1N, KP-2 and KP-3 cell lines have been cultured continuously in a medium supplemented with 10% fetal calf serum for more than 20, 21 and 17 months, respectively. The KP-2 and KP-3 cell lines produced and released carbohydrate antigen 19-9 into the spent medium but the KP-1N cell line did not. KP-1N and KP-3, produced liver metastases after intrasplenic injection into nude mice, whereas KP-2 produced few liver colonies. Cell lines highly metastatic to the liver, KP-1NLs and KP-3Ls, were isolated from the liver colonies of KP-1N and KP-3, respectively.

Aged↗
PubMed1990

Rapid and reversible inhibition by low density lipoprotein of the endothelium-dependent relaxation to hemostatic substances in porcine coronary arteries. Heat and acid labile factors in low density lipoprotein mediate the inhibition.

The effects of hemostatic substances on the vascular tone in porcine coronary arteries and the influence of low density lipoprotein on tension were investigated. Thrombin induced a marked concentration-dependent relaxation in prostaglandin F2 alpha-precontracted strips with intact endothelium, whereas it produced a modest constriction in endothelium-denuded arteries. Methylene blue abolished the relaxation, but indomethacin did not affect it significantly. An exposure of the intact strips to low density lipoprotein resulted in a marked inhibition of the relaxation to thrombin but did not interfere with vasodilation by sodium nitroprusside. The inhibition by low density lipoprotein was reversed completely by washing. In contrast, high density lipoprotein lacked such inhibitory effects. Adenosine diphosphate, calcium ionophore A23187, and platelet-activating factor also produced relaxation in the intact strips. An exposure of the strips to low density lipoprotein almost abolished relaxation to these substances. The inhibition was also reversible. Heat treatment or acid treatment of low density lipoprotein resulted in a complete loss of the inhibitory effects, but diisopropyl fluorophosphate treatment did not alter the effect. It is concluded that low density lipoprotein may play a new pathological role in promotion of coronary vasospasm through rapid and reversible inhibition in endothelium-dependent relaxation to hemostatic substances.

Acids↗
PubMed1990

FR112123, a new oligopeptide antibiotic from Streptomyces viridochromogenes. Taxonomy, fermentation, isolation, physico-chemical properties, structure and biological activity.

FR112123 is a new oligopeptide antibiotic produced by Streptomyces viridochromogenes No. 7587. The structure of FR112123 is elucidated as N-(N6-(N2-glycyl-L-glutaminyl)-D-lysyl)-D-alanine (1) by spectroscopic and chemical evidence. It resembles a partial structure of peptidoglycan in bacteria. The compound has a superior activity against an Escherichia coli mutant sensitive to inhibitors of cell wall synthesis, although it has a weak activity against the parent strain. These suggest that FR112123 might act on the biosynthesis of bacterial cell wall.

Animals↗
PubMed1990

A novel antifungal antibiotic, FR-900848. I. Production, isolation, physico-chemical and biological properties.

Streptoverticillium fervens produced a new antibiotic, FR-900848, which has a high specific activity against filamentous fungi. Purified by solvent extraction and column chromatography, the compound appears as colorless crystals. Its structure is C32H43N3O6, which consists of 5'-amino-5'-deoxy-5,6-dihydrouridine with an unsaturated fatty acid having unprecedented four serial and one isolated cyclopropane rings.

Animals↗
PubMed1990

Radial polydactyly.

Excessive longitudinal segmentation of the radial portion of the limb bud results in the clinical presentation of duplicated and triphalangeal thumbs. These are common congenital problems with various possible associated anomalies and variable inheritance patterns. Reconstruction of a thumb with stable joints, muscle balance, and good alignment requires attention to each tissue component at the time of the initial surgery.

Fingers↗