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Biomedical subjects

Y Inada

Publications and source records attributed to Y Inada.

At least 199 records · Page 11Linked to original sources

Plasma albumin is essential for collagen-induced platelet aggregation.

We found that platelets must have albumin on the surface to respond to collagen and aggregate. Albumin, however, was not absolutely necessary for ADP-, platelet activating factor-, serotonin- or thrombin-induced aggregation, while fibrinogen was required for ADP- or serotonin-induced aggregation. Immunofluorescent microscopy revealed that albumin was retained on gel-filtrated platelets but not on washed platelets. Albumin was not required for platelet adhesion to immobilized collagen. Without albumin thromboxane formation upon collagen-stimulation was diminished. These data suggest that albumin is essential in some step(s) that results in production of thromboxane A2.

Animals↗

Magnetic urokinase: targeting of urokinase to fibrin clot.

A plasminogen activator of human origin, urokinase, was endowed with magnetic property. The magnetic urokinase was composed of magnetite, polyethylene glycol derivative and urokinase, and dispersed in saline. Its particle size of magnetite was approximately 30-60 nm. It was selectively delivered to fibrin clot by magnetic force in continuously circulating plasma and exerted fibrinolytic activity without degrading fibrinogen.

Blood Coagulation Tests↗

"A" subunit of factor XIII is present on bovine platelet membrane and mediates collagen-induced platelet activation.

The Fab fragment of a polyclonal antibody against platelet factor XIII inhibited the collagen-induced platelet aggregation in a dose-dependent manner. This inhibitory effect was specific for collagen, and it had no effect on arachidonic acid-, ADP-, and serotonin-induced aggregations. This finding strengthens our notion that platelet factor XIII is involved in collagen-induced platelet aggregation. (Saito, Y., Imada, T., Takagi, J., Kikuchi, T. and Inada, Y. J. Biol. Chem. 261, 1355-1358, 1986). We have investigated membrane localization of bovine platelet factor XIII using immunological techniques. Immunofluorescent visualization revealed that the factor XIII was expressed on the surface of non-permeabilized bovine platelets, where we detected neither lactate dehydrogenase, a cytoplasmic enzyme marker, nor B subunit of factor XIII, which is present in plasma. Cell surface iodination and immunoprecipitation also confirmed that it existed on the surface of platelets.

Animals↗

Venom from southern copperhead snake (Agkistrodon contortrix contortrix). II. A unique phospholipase A2 that induces platelet aggregation.

A platelet aggregation factor was purified from the venom of southern copperhead snake (Agkistrodon contortrix contortrix) by DEAE-cellulose ion-exchange chromatography, precipitation with ammonium sulfate, affinity chromatography using bovine serum albumin as ligand, and gel filtration on Cellulofine GCL-2000. It had molecular weights of 11,000 and 14,000, as determined by gel filtration chromatography and sodium dodecyl sulfate--polyacrylamide gel electrophoresis (SDS-PAGE), respectively. It consists of a single polypeptide, and was identified as a phospholipase A2. It was quite resistant to heat and various denaturing reagents including urea and SDS. It lost both phospholipase A2 activity and platelet aggregating activity upon modification of histidine residue(s) with p-bromophenacyl bromide. Its specificity towards the beta-position of phospholipid in esterolytic reaction was confirmed by gas-liquid chromatography using a pure synthetic phosphatidylcholine. Platelet aggregation by this phospholipase A2 was completely inhibited by prostacyclin, but was little inhibited by aspirin which indicates almost no direct participation of released arachidonic acid in the aggregation mechanism.

Animals↗

Skin graft including subcutaneous vein: experimental study and clinical applications.

Skin grafting, using full and split thickness techniques, may yield poor results when satisfactory circulation is not restored in the recipient bed. Using a rabbit ear model with a vein located in the center of the graft, donor skin and subcutaneous vein were raised simultaneously, and the vein was preserved, resulting in a viable passage for inflow and outflow. Grafts were shown to survive in this experimental group when circulation was satisfactory after venous preservation. In the control group with no vein preservation, all grafts became necrotic. These results were clinically applied for cases in which skin defects, caused by finger trauma, resulted in poor circulation in the recipient bed. Skin and subcutaneous vein were simultaneously taken from the forearm and grafted successfully, resulting in excellent prognoses.

Adult↗

(R)-3-[(S)-1-carboxy-5-(4-piperidyl)pentyl]amino-4-oxo-2,3,4,5- tetrahydro-1,5-benzothiazepine-5-acetic acid (CV-5975): a new potent and long-lasting inhibitor of angiotensin converting enzyme.

The synthetic design and the biological activities of structurally new angiotensin converting enzyme (ACE) inhibitors, (R)-3-amino-4-oxo-2,3,4,5-tetrahydro-1,5-benzothiazepine-5-acetic acid derivatives, are described. A number of compounds in this series showed potent ACE inhibitory activity in vitro and in vivo. Structure-activity studies indicated that a piperidyl moiety on the amino group at the 3-position in this series conferred long-lasting ACE inhibitory activity and that the duration of activity depended on the length of the carbon chain in the 1-carboxy-omega-(4-piperidyl)alkyl group. (R)-3-[(S)-1-carboxy-5-(4-piperidyl)-pentyl]amino-4-oxo-2,3,4,5-tetrahydro- 1,5-benzothiazepine-5-acetic acid (CV-5975) was selected as the most promising ACE inhibitor for further studies because of its marked inhibitory activity.

Angiotensin-Converting Enzyme Inhibitors↗

Antihypertensive action of a new angiotensin converting enzyme inhibitor, (R)-3-[(S)-1-carboxy-5-(4-piperidyl)pentyl]amino-4-oxo-2,3,4,5-tetr ahy dro-1,5-benzothiazepine-5-acetic acid (CV-5975), in various hypertensive models.

The antihypertensive activity of a new angiotensin converting enzyme (ACE) inhibitor, CV-5975, (R)-3-[(S)-1-carboxy-5-(4-piperidyl)pentyl] amino-4-oxo-2,3,4,5-tetrahydro-1,5-benzothiazepine-5-acetic acid, was examined in normotensive rats and various hypertensive animal models. In spontaneously hypertensive rats, CV-5975 (1 to 10 mg/kg, p.o.) had a dose-related, sustained antihypertensive action, which was more potent and longer than that of enalapril. The potency and duration of action of CV-5975 was intensified when it was administered repeatedly or combined with hydrochlorothiazide. CV-5975 (1 mg/kg, p.o.) inhibited the ACE activity of plasma and tissues; inhibition on the ACE activity of the aorta, kidney, and brain was marked when CV-5975 was administered repeatedly. In 2-kidney, 1 clip hypertensive rats (1 to 10 mg/kg, p.o.) and dogs (0.3 and 1 mg/kg, p.o.), CV-5975 had a marked, sustained antihypertensive action, which was more marked than that of enalapril. In normotensive rats (10 mg/kg), 1-kidney, 1 clip hypertensive rats (3 and 10 mg/kg), and hyporeninemic DOCA/salt hypertensive rats (1 to 10 mg/kg/day), CV-5975 administered orally once or repeatedly reduced blood pressure, whereas enalapril did not. These results indicate that CV-5975 is a potent and long-lasting antihypertensive agent, the action of which is mediated primarily by inhibiting ACE activity and partly by some unknown mechanisms.

Angiotensin-Converting Enzyme Inhibitors↗

Inhibition of angiotensin converting enzyme by (R)-3-[(S)-1-carboxy-5-(4-piperidyl)pentyl]amino-4-oxo-2,3,4,5-tetra- hydro-1,5-benzothiazepine-6-acetic acid (CV-5975), a non-sulfhydryl compound.

CV-5975, (R)-3-[(S)-1-carboxy-5-(4-piperidyl)pentyl]amino-4-oxo- 2,3,4,5-tetrahydro-1,5-benzothiazepine-5-acetic acid, was found to inhibit rabbit lung angiotensin converting enzyme (ACE) activity with an IC50 of 3.1 x 10(-9) M and a Ki of 2.6 x 10(-9) M, inhibit the angiotensin I (A-I)-induced contraction of the guinea pig ileum with an IC50 of 1.3 x 10(-8) M, and augment the bradykinin (BK)-induced contraction of the ileum with an AC50 of 9.2 x 10(-10) M. The activity of CV-5975 was comparable to or slightly more potent than that of enalaprilat. The overall inhibition constant (Ki*), calculated from a steady-state analysis of enzyme reactions, was 4.4 x 10(-12) M for CV-5975; this indicates that the inhibition was about 5 times more potent than that of enalaprilat (2.0 x 10(-11) M). In rats, CV-5975 (0.03 and 0.3 mg/kg, i.v. and 3 and 10 mg/kg, p.o.) inhibited the A-I-induced pressor action more potently and for a longer period than did the corresponding doses of enalaprilat and enalapril. CV-5975 and enalapril (3 mg/kg, p.o.) augmented the BK-induced depressor action to a similar extent. In dogs, CV-5975 (0.3 and 1 mg/kg, p.o.) markedly inhibited the A-I-induced pressor action in a dose related manner, and the duration of this inhibitory activity was longer than with the corresponding doses of enalapril. These data provide evidence for the proposal that CV-5975 is a highly potent and long lasting ACE inhibitor.

Angiotensin I↗

[A study of ultrasonic scaler. The effect of the different frequencies of the ultrasonics in the experimental calculus removal and roughness of the metallic plate after scaling].

In an attempt to determine how the degree of the experimental calculus removal on the metallic plate and its roughness after scaling would be affected by ultrasonics under high or low frequency, quantitative measurement and morphological observation were made. The results obtained were as follows: 1. On the calculus removal, larger effect was obtained by high frequency unit than low frequency. 2. On the roughness of the metallic plate after scaling, larger defect was observed by high frequency unit than low frequency. 3. Scanning electron microscopically, strip like defects were observed under low frequency unit, while exfoliation of the metallic plate in addition to the strip like defects were observed under high frequency.

Dental Calculus↗

Polyethylene glycol derivative-modified cholesterol oxidase soluble and active in benzene.

Cholesterol oxidase from Nocardia sp. was modified with a synthetic copolymer of polyoxyethylene allylmethyldiether (PEG) and maleic acid anhydride (MA anhydride), poly(PEG-MA anhydride). The modified cholesterol oxidase, in which 64% of the amino groups in the protein molecule were coupled to poly(PEG-MA), was soluble in organic solvents and catalyzed the oxidation reaction of cholesterol in benzene to form 4-cholesten-3-one with the enzymic activity of 0.6 mumol/min/mg protein. Using the modified cholesterol oxidase together with polyethylene glycol-modified peroxidase, coupled reactions shown below took place in Cholesterol + O2----4-Cholesten-3-one + H2O2 H2O2 + o-Phenylenediamine----H2O + Oxidized o-Phenylenediamine transparent benzene solution, not in an emulsified system. The oxidation of cholesterol was directly determined in benzene by measuring the absorbance of oxidized o-phenylenediamine at 490 nm.

3-Hydroxysteroid Dehydrogenases↗

Fibrinolysis by urokinase endowed with magnetic property.

The activated magnetic modifier was synthesized from magnetite, alpha, omega-dicarboxymethylpoly(oxyethylene) and N-hydroxysuccinimide (Biochem. Biophys. Res. Commun., 145, 908-914, 1987). Urokinase was directly coupled with the activated magnetic modifier to obtain magnetic urokinase. The magnetic urokinase dispersed in saline and exerted high fibrinolytic activity (13.8 X 10(4) IU/mg protein), and was readily recovered from saline by magnetic force of 250 Oe. By applying magnetic force, the urokinase was attracted at our will and local fibrinolysis was achieved on fibrin gel in a petri dish.

Fibrinolysis↗

Chemical modification of enzymes with activated magnetic modifier.

An activated magnetic modifier, which could render biological materials magnetic property, was synthesized in following two steps: oxidation of ferrous ions (Fe2+) with hydrogen peroxide in the presence of alpha, omega-dicarboxymethylpoly(oxyethylene) (DCPEG) to obtain DCPEG-magnetite (Fe3O4); free carboxyl groups in the DCPEG-magnetite were activated with N-hydroxysuccinimide. By coupling the activated magnetic modifier to amino groups of lipase or L-asparaginase, magnetic enzymes were prepared. They dispersed stably not only in aqueous solution but also in organic solvents with high enzymic activities. Magnetic enzymes were readily recovered from reaction mixture in a magnetic field of 6000 Oe without loss of enzymic activity.

Asparaginase↗