Search PubMed⌕ Search

Biomedical subjects

K Matsuda

Publications and source records attributed to K Matsuda.

At least 667 records · Page 37Linked to original sources
PubMed1985

Isolation of enzymes from polyacrylamide disk gels by a centrifugal homogenization method.

A sliced segment of polyacrylamide gel was quickly homogenized without any loss of gel pieces. The gel segment was placed on a disposable pipet tip, which was packed with a small amount of lumped copper wires and held in a microfuge tube. The gel was homogenized by centrifugation for 15 s at 15,000 g at 0 to 4 degrees C. Almost 70% of endodextranase activity could be recovered from homogenized gel within 30 min at 4 degrees C, whereas only 20% of activity was eluted from gel slices. If necessary, copper wire could be replaced by fine stainless-steel wire or by the nylon string used in fishing lines. Proteins could also be recovered from the homogenized gel by charging electric current for 1 h at 4 degrees C.

Centrifugation↗
PubMed1985

Inhibition of phospholipases by Met-Leu-Phe-Ile-Leu-Ile-Lys-Arg-Ser-Arg-His-Phe, C terminus of middle-sized tumor antigen.

The N and C terminals and tyrosine-phosphorylating site of the middle-sized tumor antigen of polyoma virus were chemically synthesized. The sequences of these peptides were Met-Asp-Arg-Val-Leu-Ser-Arg-Ala-Asp-Lys (N-MT), Met-Leu-Phe-Ile-Leu-Ile-Lys-Arg-Ser-Arg-His-Phe (C-MT), and Glu-Glu-Glu-Glu-Tyr-Met-Pro-Met-Glu (MT-Tyr), respectively. Among these peptides, the C-MT peptide inhibited phospholipase A2 (EC 3.1.1.4), phospholipase C (EC 3.1.4.3), and phospholipase D (EC 3.1.4.4). In addition, phosphatidylinositol-specific phospholipase C (EC 3.1.4.10) was also inhibited by this peptide. To study the mechanism of the inhibition, kinetic analysis was performed using phospholipase A2 from porcine pancreas. The degree of inhibition of phospholipase was dose dependent, and maximal inhibition was observed at pH 8.8. This peptide inhibited phospholipase A2 in a competitive manner for low-affinity sites of Ca2+, and in a noncompetitive manner for phospholipid substrates. When a fatty acid in the 2 position of the glycerol moiety of phosphatidylcholine was replaced by palmitic acid (C16:0), oleic acid (C18:1), linoleic acid (C18:2), eicosatrienoic acid (C20:3), or arachidonic acid (C20:4), the degree of inhibition of phosphatidylcholine hydrolysis by the C-MT peptide decreased. Inhibition of phospholipase A2 by the C-MT peptide was reversed by low concentrations of sodium deoxycholate but not by Triton X-100 or Nonidet P40, nonionic detergents. These detergents and the modification of acyl groups altered the micellar state of phospholipids. These results, taken together, suggest that the binding of the C-MT peptide near the low-affinity Ca2+ binding sites modifies the interaction of phospholipid substrates with the active center of phospholipase A2.

Animals↗
PubMed1985

In-vitro antibacterial activity of AMA-1080.

The in-vitro antibacterial activity of AMA-1080 against both Gram-positive and Gram-negative clinical isolates was studied in comparison with that of aztreonam, cefotaxime, ceftazidime and cefoperazone. AMA-1080 showed a potent antibacterial activity against Gram-negative bacteria, particularly, the strains of Enterobacteriaceae. In addition, AMA-1080 inhibited the strains of genus Pseudomonas at the low concentrations. However, AMA-1080 showed less active against Gram-positive bacteria. It was found that AMA-1080 was highly resistant to hydrolysis by both chromosomal and plasmid-mediated beta-lactamases.

Anti-Bacterial Agents↗
PubMed1985

A novel enzyme producing isoprimeverose from oligoxyloglucans of Aspergillus oryzae.

An enzyme producing isoprimeverose from xyloglucan fragment oligosaccharides has been purified to the electrophoretically pure state from a commercial enzyme preparation of Aspergillus oryzae (Sanzyme 1000). The purified enzyme showed approximately 1,280-fold increase of the specific activity over the original preparation. The purified enzyme was shown to be an oligomeric protein consisting of two subunits, each of which had a molecular weight of 115,000. The enzyme showed the highest activity at pH 5.0 and 60 degrees C, and was stable in the pH range from 5 to 7 and at up to 50 degrees C. The isoelectric point of this enzyme was pH 3.9. The purified enzyme was highly specific for xyloglucan fragment oligosaccharides and split off isoprimeverose units from the non-reducing end of the backbone of the substrate.

Amino Acids↗
PubMed1985

Purification and properties of an alpha-D-xylosidase from Aspergillus niger.

Two components of alpha-D-xylosidase (alpha-D-xylosidase I and II) were detected in the culture filtrate of Aspergillus nigher grown in a medium containing Sanzyme 1000-treated Glyloid 2A. The major component (alpha-D-xylosidase I) was purified to an electrophoretically pure state. The purified enzyme showed approximately 540-fold increase in specific activity over the original culture filtrate. The purified enzyme was shown to be an oligomeric protein consisting of four subunits, each of which had a molecular weight of 123,000. The enzyme showed the highest activity at pH 2.5-3.0 and 45 degrees C, and was stable in the pH range from 3.0 to 7.0 and at the temperatures up to 60 degrees C. The isoelectric point of this enzyme was pH 5.6. The purified enzyme was highly specific for p-nitrophenyl alpha-D-xylopyranoside and isoprimeverose (6-O-alpha-D-xylopyranosyl-D-glucopyranose). The apparent Km and Vmax values of the enzyme for p-nitrophenyl alpha-D-xylopyranoside and isoprimeverose were 10.5 mM and 40.8 mumol/min/mg protein, and 2.2 mM and 30 mumol/min/mg protein, respectively. The purified enzyme could also split off the alpha-D-xylopyranosyl residue on the non-reducing terminal of the backbone of oligoxyloglucans such as alpha-D-xylopyranosyl-(1----6)-beta-D-glucopyranosyl- (1----4)-[(alpha-D-xylopyranosyl-(1----6)-]-beta-D-glucopyranosyl- (1----4)-] 2-D-glucopyranose.

Amino Acids↗
PubMed1985

Comparison of beta-glucan structures in a cell wall mutant of Saccharomyces cerevisiae and the wild type.

A mutant of Saccharomyces cerevisiae defective in the cell wall beta-glucan structure was obtained. The mutant cells are extremely sensitive to (beta 1-3)-glucanase digestion and mild alkali treatment. Structural analysis revealed that the alkali-insoluble, skeletal glucan from wild type cells contains two components, a (beta 1-3) linked glucan with a laminated structure, and a highly branched glucan containing predominantly (beta 1-6) linkages. The mutant cells lack the latter component.

Cell Wall↗
PubMed1985

Effect of oxygen on the corrosion of dental amalgam.

The anodic and cathodic polarization of five dental amalgams were determined as a function of oxygen concentration in Ringer's solution and artificial saliva. The results indicate an anodic polarization behaviour dependent on Cl ion concentration and a corrosion potential determined primarily by oxygen concentration. At high oxygen concentrations the corrosion rates of traditional and copper enriched amalgams were equivalent.

Copper↗
PubMed1985

In vitro antibacterial activity of Sch 34343 and its stability to beta-lactamases and renal dehydropeptidase 1.

The in vitro antibacterial activity of Sch 34343 against 1,328 strains of clinical isolates was compared with those of imipenem and ceftazidime. Sch 34343 had a broad spectrum of antibacterial activity against both gram-positive and gram-negative bacteria but was inactive against Pseudomonas aeruginosa and Pseudomonas maltophilia. Sch 34343 was quite stable to hydrolysis by beta-lactamases, including both penicillinases and cephalosporinases. However, Sch 34343 was slightly hydrolyzed by a new type of beta-lactamase (oxyiminocephalosporin beta-lactamase), as was imipenem. Sch 34343 was slightly hydrolyzed by renal dehydropeptidase 1 but was somewhat more stable than other carbapenems.

Animals↗
PubMed1985

Purification and some properties of a low molecular weight trypsin inhibitor from acute pancreatitis urine.

Urinary trypsin inhibitors (UTIs) from the urine of a patient with acute pancreatitis consisted of three forms with different molecular weights. These were highly purified by ammonium sulfate precipitation, Sephadex G-75, SP-Sephadex C-25 and trypsin-Sepharose 4B column chromatography. The lowest molecular weight of UTIs was estimated to be 6,200 daltons. Moreover, five residues of N-terminal amino acids and a C-terminal amino acid were the same as those of pancreatic secretory trypsin inhibitor.

Acute Disease↗
PubMed1985

Ventricular arrhythmias late after aortic and/or mitral valve replacement.

Since it is not yet known whether ventricular arrhythmias in patients with valve replacement are associated with an increased risk of sudden death, as in patients with coronary artery disease, a total of 46 patients who were long-term survivors of aortic and/or mitral valve replacement were examined with 24-hour ambulatory electrocardiographic monitoring, and the factors influencing the occurrence of ventricular arrhythmias were analyzed. The significance of ventricular arrhythmias in the prognosis of valve replacement is discussed. The occurrence of ventricular arrhythmias was significantly higher: 1) in patients with aortic stenosis than in those with aortic regurgitation, 2) in patients with multiple valve surgery than in those with single valve replacement and 3) in patients with larger heart size. Pre- and postoperative hemodynamics, including left ventricular function, were not significantly related to the incidence of ventricular arrhythmias. A review of the patients who died suddenly, late after valve replacement suggests that frequent ventricular arrhythmias and thromboembolism are the most important factors in the late mortality of these patients. The prognostic significance of postoperative ventricular arrhythmias in patients with valve replacement requires additional study.

Adolescent↗
PubMed1985

Evaluation of the induction of hepatic drug-metabolizing enzymes in the rat and mouse treated with temazepam using trimethadione as the indicator.

In the present paper we report the effect of high doses of temazepam on drug-metabolism induction in rat and mouse. Temazepam induced a dose-dependent and reversible increase of hepatic microsomal drug-metabolizing enzymes in the rat, dose-correlated increase of dimethadione/trimethadione ratios in plasma of the rat, and dose-related shortening of hexobarbital-induced sleeping time in the mouse. In this study trimethadione is considered a good indicator for estimating the state of hepatic enzyme induction.

Aminopyrine N-Demethylase↗
PubMed1985

Studies on antiviral agents. II. Synthesis and in vitro antiviral activity on new kanamycin A derivatives having higher acyl group at N-1 position.

The synthesis and antiviral activity of 3''-N-trifluoroacetylkanamycin A derivatives (6) having higher acyl group at the N-1 position are described. On the basis of the structure-activity relationships between antiviral activity and alkyl chain length in an acyl group at the N-1 position, analogs (6f approximately I) having higher alkylcarbonyl group exhibited antiviral activity against not only HSV-I but also influenza virus. Analogs (6q approximately v) having higher alkyloxycarbonyl group showed antiviral activity against HSV-I. In addition, kanamycin A derivatives (6n, o, y, z) possessing higher alkylcarbonyl group with a functional group, higher alkylaminocarbonyl group, and higher alkylthiocarbonyl group had antiviral activity against HSV-I. The analog (6h) showed a broad antiviral spectrum against both DNA (HSV-I, HSV-II, VZV) and RNA (influenza) viruses.

Antiviral Agents↗
PubMed1985

Total synthesis of 3-O-demethylsporaricin A.

The novel, semisynthetic pseudodisaccharide antibiotic, 3-O-demethylsporaricin A, was synthesized via 3-O-demethylsporaricin B obtained by glycosidation of its aminocyclitol part. The aminocyclitol part was synthesized as D,L-form from D,L-(1,2,3/4,5,6)-1,4-bis(benzyloxy-carbonylamino)-5,6-O-isopropyl idene-2,3,5,6-cyclohexanetetraol via three key steps, namely, deoxygenation, inversion of a hydroxyl group, and N-methylation. The physical and biological properties of synthetic 3-O-demethylsporaricin A and an authentic sample derived from sporaricin B were identical.

Aminoglycosides↗
PubMed1985

Studies on antiviral agents. III. Synthesis and in vitro antiviral activity of 1-N-higher-acyl-3"-N-functionalized acylkanamycin A derivatives.

The synthesis and antiviral activity of 1-N-palmitoyl- or 1-N-(3-hydroxytetradecanoyl)-kanamycin A derivatives (7,8) having various type of acyl substituents at the N-3" position were investigated. The structure-activity relationships between the antiviral activity and the substituent at the N-3" position is described. In this series, 3"-N-acetyl-1-N-palmitoyl-kanamycin A (7c) showed the excellent antiviral activity against HSV-I and influenza virus. Further, we examined the synthesis and the antiviral activity of 3"-N-glycylkanamycin A derivatives (9) having a higher-acyl group at the N-1 position. The 3"-N-glycyl-1-N-pentadecanoylkanamycin A (9a) also exhibited excellent antiviral activity.

Amikacin↗