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Biomedical subjects

T Tanimoto

Publications and source records attributed to T Tanimoto.

At least 181 records · Page 10Linked to original sources
PubMed1993

Preparation, isolation, and characterization of novel heterogeneous branched cyclomalto-oligosaccharides having beta-D-galactosyl residue(s) on the side chain.

Transgalactosylated products of branched cyclodextrins (glucosyl-alpha CD, -beta CD, -gamma CD, and maltosyl-alpha CD, -beta CD, -gamma CD) were synthesized by beta-D-galactosidases from Bacillus circulans and Penicillium multicolor using lactose as a donor substrate and branched CDs as acceptors. Eighteen beta-D-galactosylated branched CDs were isolated and purified by HPLC. Their structures were elucidated by FABMS and 13C NMR spectroscopies, and methylation analysis. The chromatographic behavior of these novel heterogeneous branched CDs on three HPLC columns of different separation modes was compared.

Bacillus↗
PubMed1993

Conversion of a NADPH-dependent aldehyde reducing enzyme into aldose reductase.

1. Aldose reductase, aldehyde reductase and high-Km aldose reductase were purified from the inner medulla of dog kidney. 2. Compared with aldose reductase, high-Km aldose reductase had a lower isoelectric point, a lower activity for aldo-sugars and a lower sensitivity for aldose reductase inhibitors, and it was not activated by sulfate ions. Both reductases had the same molecular weight (38,500) and immunochemical properties. 3. High-Km aldose reductase was easily converted into an aldose reductase-like enzyme, namely a generated reductase upon incubation in neutral buffer solution. 4. The generated reductase was identical with aldose reductase with respect to the isoelectric point, substrate specificity, activation by sulfate ions and IC50 values for aldose reductase inhibitors. The generated reductase revealed immunochemical identity with aldose reductase as well as high-Km aldose reductase.

Aldehyde Reductase↗
PubMed1993

Cutaneous plexiform schwannoma in a pig.

A plexiform schwannoma (PFS) observed as a solitary mass in the dermis of a 6-month-old pig consisted of schwannoma cells of Antoni A type and B type. Neoplastic cells in Antoni A type areas sometimes showed cord-like outgrowths or a neurofibromatous pattern. Neoplastic cells in Antoni B type areas showed erythrophagocytosis, some encircling the microvasculature. Immunohistochemically, neoplastic cells were strongly positive for S-100 protein and vimentin. Peripheral parts of the nodules were cytokeratin (clone AE1/AE3)-positive, as in normal swine perineurial cells. Double immunostaining clearly demonstrated neoplastic cells doubly positive for both S-100 protein and cytokeratin, suggesting that S-100-positive Schwann cells and cytokeratin-positive perineurial cells are functional variants of the same cell type. Ultrastructurally, neoplastic cells in Antoni A type areas possessed characteristics of Schwann cells, such as cytoplasmic interdigitation, external laminae and intercellular junctions. At the periphery of the nodules, features of perineurial cells were detected. Neoplastic cells in Antoni B type areas seemed to be undergoing degenerative processes similar to those in Antoni A type regions and they contained many lysosomes. The neoplasm was generally similar in both location and histology to that seen in man, but there were some histological, immunohistochemical and ultrastructural differences. This is the first reported case of PFS in domestic animals.

Animals↗
PubMed1993

Preparation of di-O-triphenylmethyl-(trityl-)cyclomalto-octaoses, and isolation and characterization by "hex-5-enose degradation" of four positional isomers.

Four regioisomeric ditritylated derivatives of cyclomalto-octaose (1, cG8), namely, 6(I),6(n)-di-O-trityl-cG8S have been prepared by the reaction of 1 with chlorotriphenylmethane in pyridine and isolated by high-performance liquid chromatography. The regiochemical determination of the four ditrityl-substituted derivatives has been achieved by means of the "hex-5-enose degradation," followed by examination of the products by fast-atom bombardment-mass spectrometry.

Carbohydrate Sequence↗
PubMed1993

Heterotopic splenic tissue in the liver of a swine.

A heterotopic splenic tissue (HST) was observed in the diaphragmatic face of the right hepatic lobe of a 6-month-old, female mixed bred swine. Macroscopically, HST was a solitary, well-demarcated intrahepatic nodule, 1 x 0.5 x 0.5 cm in size. Other organs including original spleen showed no macropathological abnormalities. Histological findings of HST were essentially similar to those of the original spleen, receiving feeding blood vessels from hepatic portal vein. To our knowledge, the present case is the first report of HST in the liver not only of domestic animals but also of man.

Animals↗
PubMed1993

[High Molecular Weight Urokinase Reference Standard (Control 901) of National Institute of Health Sciences].

A candidate for "High Molecular Weight Urokinase Reference Standard (HMW-UK RS, Control 901)" of the National Institute of Health Sciences (NIHS) was examined for evaluating the fibrinolytic activity. The urokinase activity of the candidate HMW-UK RS was determined by "two-stage method" as 800 Unit/Amp. against the present Urokinase Reference Standard (Control 881), through the collaborative study involving five laboratories. According to the gel-permeation chromatography of the candidate for the molecular determination, it was confirmed that more than 97% of the total urokinase activity was attributed to the higher molecular fraction, named HMW-UK. Thus it was authorized as the High Molecular Weight Urokinase Reference Standard of the NIHS.

Government Agencies↗
PubMed1993

[Studies on the quality of enzyme preparations (XII)--lysozyme preparations].

This paper was described the results of the weight variation test and the assay for the potency of the commercially available lysozyme preparations (samples: 13 kinds of granules, in which 10 kinds are granules (folded)) collected for the legal sampling inspection in 1992. The potencies of 10 samples were found to be within the range of permissible content, when the all samples extracted with phosphate buffer were determined by the method described in Japanese Standards of Pharmaceutical Ingredients. However, the potencies of 3 samples were not more than 65% of the labeled potencies. These low potency samples showed the potencies of 98-106%, when 0.4M sodium chloride solution or 0.1N hydrochloric acid was used instead of phosphate buffer for enzyme extraction. The weight variation test showed all preparations to be within the permissible JP XII deviation range (10%) for "granules (folded)".

Dosage Forms↗
PubMed1993

[Prefeeding of aldose reductase inhibitor inhibits galactose cataract].

To examine the effect of prefeeding the aldose reductase inhibitor (ARI) on the cataract induced by the subsequent feeding of galactose diet, rats were first fed rat chow with or without ARI for 2 weeks. The animals were then transferred to a 25% galactose diet for different periods of time. Lenses were enucleated and examined by light microscopy. The amount of galactitol in the lenses was examined biochemically. The cataract was less severe and there was less galactitol in the lenses in the rats first fed with ARI than in those without ARI. These results indicate that the feeding the ARI prior to galactose feeding partly inhibits galactose cataract.

Aldehyde Reductase↗
PubMed1992

Site-directed mutagenesis of His-42, His-188 and Lys-263 of human aldose reductase.

The role of His42, His188, and Lys263 residues in the catalytic action of human aldose reductase was investigated in association with various inhibitors of this enzyme by site-directed mutagenesis. While mutations at His42- greater than Gln, His42- greater than Tyr, His188- greater than Gln, and His188- greater than Tyr brought small change in the kinetic parameters, Lys263- greater than Glu mutation markedly increased the Km value for the substrate DL-glyceraldehyde by a factor of 60. Lys263- greater than Met substitution resulted in approximately 14 fold elevation of Km for the substrate. By contrast, mutation of Lys263- greater than Arg significantly decreased the Km for the substrate with concomitant reduction in kcat. Moderate increase in Km values for the cofactor NADPH was demonstrated for mutated enzymes. These results are indicative of the possible role of Lys263 in the substrate binding through electrostatic interaction. The inhibitor constants (Ki) for structurally diverse aldose reductase inhibitors against mutated enzymes demonstrated different degree of alteration, indicating binding sites of aldose reductase inhibitors on the enzyme molecule vary from one another, and some of the sites are more closely correlated with the physicochemical property of Lys263.

Aldehyde Reductase↗
PubMed1992

Preparation of di-O-triphenylmethyl-(trityl-) cyclomaltohexaoses and -cyclomaltoheptaoses and characterization of three positional isomers of each by the "hex-5-enose degradation".

Regioisomeric 6(1),6n-di-O-trityl-cyclomaltohexaoses (cG6s) or -cyclomaltoheptaoses (cG7s) were prepared by the reaction of cyclomaltohexaose (1, cG6) or cylomaltoheptaose (5, cG7) with chlorotriphenyl-methane in pyridine and isolation by h.p.l.c. The regiochemical determination of each three ditrityl-substituted derivatives has been accomplished by the "hex-5-enose degradation", followed by measurement of their f.a.b.-mass spectra.

Carbohydrate Conformation↗
PubMed1992

Preparation of three positional isomers of diglucosyl-cyclomaltohexaose.

Three positional isomers of diglucosyl-cyclomaltohexaose (diglucosyl-cG6) were chemically synthesized via 6(1),6(2)-, 6(1),6(3)-, and 6(1),6(4)-di-O-(TERT-butyldimethylsilyl)-cG6S (1, 2, and 3) prepared regiospecifically. Glucosylation of bis(2,3-di-O-acetyl)tetrakis(2,3,6-tri-O-acetyl)-CG6S obtained from the three regioisomeric compounds 1, 2, and 3 with 2,3,4,6-tetra-O-benzyl-1-O-trichloroacetimidoyl-alpha-D-glucopyran ose, followed by debenzylation and then deacetylation, afforded 6(1),6(2)-, 6(1),6(3)-, and 6(1),6(4)-di-O-(alpha-D-glucopyranosyl)-cG6S (10, 11, and 12) together with configurational isomers. The desired compounds 10, 11, and 12 containing two (1----6)-alpha-linkages were isolated from the mixtures of their configurational isomers by high performance liquid chromatography. The three diglucosyl-cG6S synthesized chemically were used as authentic samples to identify the components in a mixture of diglucosyl-cG6S produced by an enzymatic process.

Carbohydrate Sequence↗
PubMed1992

Synthesis and aldose reductase inhibitory activities of benzyl 2-oxazolecarbamate analogues.

Various analogues of benzyl 5-phenyl-2-oxazolecarbamate (1a) were synthesized, and the structure-activity relationship of these analogues as aldose reductase inhibitor was studied. The carbamate group was necessary for the inhibitory activity. The introduction of an alkyl group at the C-4 position of 1a enhanced the inhibitory activity, however, the N-carboxymethyl group on the carbamate moiety counteracted to a hydrophobic interaction between the alkyl group at the C-4 position and the enzyme molecule.

Aldehyde Reductase↗
PubMed1992

Galactosylation at side chains of branched cyclodextrins by various beta-galactosidases.

The galactosyl transfer reaction to branched cyclodextrins (CDs) was investigated using lactose as a donor substrate and branched CDs as acceptors by various beta-galactosidases. Bacillus circulans beta-galactosidase synthesized galactosyl transfer products to branched CDs, of which the galactose residues were linked at side chains of branched CDs, not directly at CD rings. Aspergillus oryzae and Penicillium multicolor beta-galactosidases also produced derivatives galactosylated at side chains of branched CDs. The structures of main transgalactosylation products of branched CDs by these beta-galactosidases seem to be different from those by B. circulans beta-galactosidase, judging from the retention times on high performance liquid chromatography.

Bacillus↗
PubMed1992

Isolation and characterization of new peptide antibiotics, plusbacins A1-A4 and B1-B4.

New antibiotics, plusbacins A1-A4 and B1-B4, were isolated from the culture broth of a strain of Pseudomonas sp. These antibiotics were isolated as a complex by column chromatographies on Diaion HP-20 and silica gel, and then separated by HPLC. They are amphoteric in nature. The hydrochlorides are obtained as colorless powders, soluble in methanol and alkaline water. From their physico-chemical properties, these antibiotics are presumed to be acyloctapeptides containing a lactone linkage, and their differences occur in amino acid and fatty acid residues. The antibiotics are active against Gram-positive bacteria in vitro and in vivo.

Amino Acids↗
PubMed1992

[Formation of congenital cataract in the offspring of galactosemic rats].

It has been established that lenses of offspring of galactosemic rats form sugar cataracts. In the present study, in order to clarify the critical period in pregnancy for the cataract formation, lenses of offspring of pregnant rats which were fed galactose diets at each of three terms of pregnancy, were examined histologically and biochemically. Severe cataract and a large amount of galactitol in the lenses were found in the offspring of rats fed a galactose diet in the last term of pregnancy. Moreover, focal cataract was found in the offspring of rats fed a galactose diet in the middle term. These results indicate that the critical period in pregnancy for cataract formation of the offspring is the last term of pregnancy and that cataract formation begins in the middle term in offspring of galactosemic rats.

Administration, Oral↗
PubMed1991

Characterization of five isomers of branched cyclomaltoheptaose (beta CD) having degree of polymerization (d.p.) = 9: Reinvestigation of three positional isomers of diglucosyl-beta CD.

It has been confirmed by methylation analyses and chemical syntheses that three isomers of branched cyclomaltoheptaose (beta CD) isolated from the mother liquors of a large-scale preparation of beta CD with Bacillus ohbensis cyclomaltodextrin glucanotransferase are 6(1),6(4)-di-O-(alpha-D-glucopyranosyl)-cyclomaltoheptaose (1), 6(1),6(3)-di-O-(alpha-D-glucopyranosyl)-cyclomaltoheptaose (2), and 6-O-(alpha-isomaltosyl)-cyclomaltoheptaose (4) instead of 6(1),6(2)-di-O-(alpha-D-glucopyranosyl)-cyclomaltoheptaose (3), which was erroneously characterized in an earlier paper. Compound 3 has been newly isolated from a glucosyl-beta CD mixture prepared by hydrolysis with glucoamylase of a maltosyl-beta CD mixture, synthesized from maltose and beta CD through the reverse action of pullulanase. Chromatographic behavior and spectral data (13C-n.m.r. and f.a.b.-m.s.) of these isomers of branched beta CD (1-4), as well as those of another isomer prepared by the reverse action of hydrolytic enzymes, 6-O-(alpha-maltosyl)-cyclomaltoheptaose (5), were compared.

Carbohydrate Sequence↗