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Biomedical subjects

S Funakoshi

Publications and source records attributed to S Funakoshi.

At least 109 records · Page 6Linked to original sources
PubMed1975

Characterization of two glycoasparagines isolated from the urine of patients with aspartylglycosylaminuria (AGU).

Two major glycoasparagines (2-acetamido-N-(4'-L-aspartyl)-2-deoxy-beta-D-glycosylamines) were isolated from the urine of patients with aspartylglycosylaminuria (AGU). They were composed of equimolar amounts of sialic acid, galactose, glucosamine, and aspartic acid. They were isomeric with respect to the position of sialic acid attachment, since they produced the same glycoasparagine on incubation with the neuraminidase from Clostridium perfringens. The structure of the resulting sialic acid-free glycoasparagine was determined as beta-Gal-(1 leads to 4)-beta-GlcNAc-Asn based on the following findings. It produced galactose on incubation with beta-galactosidase, and N-acetyllactosamine and aspartic acid on incubation with 4-L-aspartylglycosylamine amindo hydrolase.

Amidohydrolases↗
PubMed1974

[Studies on the properties of the component of plasmin-treated IgG and the relation between IgG aggregates and complement-fixing ability (author's transl)].

No distinct differences were noted in the components of plasmin-treated IgG from the known components of papain-treated IgG (Fab and Fc fragments and untreated IgG) on the physicochemical and the immunological properties and the biological activities. Incubation of IgG with 30 cu/g of plasmin for 96 hours at 20 degrees C was found to be optimum. The plasmin-treated IgG by this condition, which gives complement-fixing ability (C'H50) below 23, did not show blood pressure depression, i.e. below 10% for dogs. Three components (Pl-Fab, Pl-Fc and Pl-IgG) were isolated from the plasmin-treated IgG by gel filtration on Sephadex G200 and CM-cellulose column chromatography. The Pl-Fc and the Fc isolated from the papain-treated IgG were obtained in crystalline forms. The extinction coefficients at 280 nm were 14.0 (IgG), 14.2 (Pl-Fab) and 14.1 (Pl-Fc). The molecular weights were 163,000, 58,000 and 54,000 and the S20,w values were 6.82, 3.82 and 3.77 for Pl-IgG, Pl-Fab and Pl-Fc, respectively. These three components were identical with IgG, Fab and Fc, respectively, on the electrophoretic and the immunological demonstrations. The titer of complement-fixation of IgG was decreased from 49 to 19 by plasmin treatment, however, it was retained at low level even in each isolated component. Whe 7S IgG was incubated at 37 degrees C, reaggregation was observed, as generally understood accompanying by elevated complement-fixing ability. Whereas it was noticed after long-term incubation of plasmin-treated IgG that the changes of complement-fixing ability could occur independently from the amount of aggregates. This fact was clearly revealed on the experiments in which IgG was treated at pH 3 in glycine buffer solution.

Animals↗
PubMedDate not supplied

Possible mechanisms of positive inotropic action of synthetic human calcitonin gene-related peptide in isolated rat atrium.

The effect of synthetic human calcitonin gene-related peptide (hCGRP) on the isolated and electrically driven left atria of rats were investigated. The peptide at concentrations of 3 X 10(-9)-3 X 10(-7) M produced positive inotropic effects on the left atria in a dose-dependent manner. Verapamil (10(-5) M) and adenosine (10(-4) M) reduced the positive inotropic effect of hCGRP at concentrations of 3 X 10(-9) and 3 X 10(-8) M, but not at that of 3 X 10(-7) M. Ouabain (5 X 10(-5) M) inhibited the effect of hCGRP in concentrations of 3 X 10(-7) and 3 X 10(-8) M, but not in that of 3 X 10(-9) M. Simultaneous pretreatment with verapamil (10(-5) M) and ouabain (5 X 10(-5) M) suppressed the positive inotropy by hCGRP at all concentrations tested. On the other hand, tetrodotoxin (10(-6) M) potentiated only the positive inotropic effect of 3 X 10(-7) M hCGRP. Metoprolol (10(-7) M) and theophilline (10(-3) M) did not affect the inotropic effect of hCGRP. These results suggest that the positive inotropic effect of hCGRP is not mediated by beta-adrenoceptors but by two distinct mechanisms of action, which was inhibited by verapamil but not by ouabain (facilitation of Ca++ influx in lower concentrations of hCGRP) and which was blocked by ouabain but not by verapamil and potentiated by tetrodotoxin (inhibition of Na+/Ca++ exchange mechanism at higher concentrations of hCGRP).

Adenosine↗
PubMedDate not supplied

Effects of synthetic human pancreastatin on pancreatic secretion and blood flow in rats and dogs.

Effects of synthetic human pancreastatin-52 and human pancreastatin-29 on pancreatic secretion and blood flow were examined in rats and dogs. Synthetic human pancreastatin-52 and human pancreastatin-29 were equally potent in suppressing the release of amylase stimulated by cholecystokinin in rats in vivo. However, neither human pancreastatin-52 nor human pancreastatin-29 altered basal and cholecystokinin-stimulated amylase release from isolated dispersed rat pancreatic acini. In studies in dogs, human pancreastatin-29 suppressed releases of amylase and protein stimulated by cholecystokinin, but did not alter pancreatic blood flow. These results suggest that the inhibitory effects of pancreastatin on pancreatic secretion do not involve a direct action on pancreatic acinar cells nor alteration of pancreatic blood flow. Pancreastatin probably is important in regulating exocrine pancreatic secretions as well as endocrine pancreatic secretions.

Amylases↗
PubMedDate not supplied

Conventional and high-yield synthesis of DTPA-conjugated peptides: application of a monoreactive DTPA to DTPA-D-Phe1-octreotide synthesis.

Successful imaging of somatostatin receptor-positive tumors with 111In-DTPA-D-Phe1-octreotide has stimulated development of peptide radiopharmaceuticals using DTPA as the chelating agent. However, use of cyclic DTPA dianhydride (cDTPA) resulted in low synthetic yields of DTPA-peptide by either solution or solid-phase syntheses. This paper reports a novel high-yield synthetic procedure for DTPA-D-Phe1-octreotide that is applicable to other peptides of interest using a monoreactive DTPA derivative. A monoreactive DTPA that possesses one free terminal carboxylic acid along with four carboxylates protected with tert-butyl ester (mDTPA) was synthesized. Fmoc-Thr(tBu)-ol, prepared from Fmoc-Thr(tBu)-OH, was loaded onto 2-chlorotrityl chloride resin. After construction of the peptide chains by Fmoc chemistry, mDTPA was coupled to the alpha amine group of the peptide on the resin in the presence of 1,3-diisopropylcarbodiimide and 1-hydroxybenzotriazole. Treatment of the mDTPA-peptide-resin with trifluoroacetic acid-thioanisole removed the protecting groups and liberated [Cys(Acm)2,7]-octreotide-D-Phe1-DTPA from the resin. Iodine oxidation of the DTPA-peptide, followed by the reversed-phase HPLC purification, produced DTPA-D-Phe1-octreotide in overall 31.8% yield based on the starting Fmoc-Thr(tBu)-ol-resin. The final product gave a single peak on analytical HPLC, and amino acid analysis and mass spectrometry confirmed the integrity of the product. 111In radiolabeling of the product provided 111In-DTPA-D-Phe1-octreotide with > 95% radiochemical yield, as confirmed by analytical reversed-phase HPLC, TLC, and CAE. These finding indicated that use of mDTPA during solid-phase peptide synthesis greatly increased the synthetic yield of DTPA-D-Phe1-octreotide, due to the absence of nonselective reactions that are unavoidable when cDTPA is used. These results also suggested that mDTPA would be a versatile reagent to introduce DTPA with high yield into peptides of interest.

Octreotide↗