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Biomedical subjects

H Iwase

Publications and source records attributed to H Iwase.

At least 199 records · Page 11Linked to original sources
PubMed1992

Partial purification and characterization of an endo-alpha-N-acetylgalactosaminidase from the culture medium of Streptomyces sp. OH-11242.

For the purification of a new type of endo-alpha-N-acetylgalactosaminidase from the culture medium of Streptomyces sp. OH-11242 (endo-GalNAc-ase-S) [Iwase, Ishii, Ishihara, Tanaka, Omura & Hotta (1988) Biochem. Biophys. Res. Commun. 151, 422-428], a method for assaying enzyme activity was established. Using purified pig gastric mucus glycoprotein (PGM) as the substrate, oligosaccharides liberated from PGM were pyridylaminated, and the reducing terminal sugars of oligosaccharides larger than Gal beta 1-3GalNAc were analysed by h.p.1.c. The crude enzyme of endo-GalNAc-ase-S was prepared as an 80% (w/v) ammonium sulphate precipitate from the concentrated culture medium. The enzyme was partially purified by gel chromatofocusing and subsequent DEAE-Toyopearl chromatography. Endo-enzyme activity eluted around pI 4.8 on a gel chromatofocusing column and eluted with 0.19-0.25 M-NaCl on a DEAE-Toyopearl column. In the enzyme fraction obtained, no exo-glycosidases or proteases could be detected. The molecular mass of the enzyme was estimated as 105 kDa by gel filtration, and the optimum pH was 5.5. Endo-GalNAc-ase-S hydrolysed the O-glycosidic linkage between GalNAc and Ser (Thr) in 3H-labelled and unlabelled asialofetuin, liberating both the disaccharide (Gal beta 1-3GalNAc) and the tetrasaccharide [Gal beta 1-3 (Gal beta 1-4GlcNAc beta 1-6)GalNAc]. When endo-alpha-N-acetylgalactosaminidase from Alcaligenes sp. (endo-GalNac-ase-A) was incubated with 3H-labelled and unlabelled asialofetuin, only the disaccharide (Gal beta 1-3GalNAc) was liberated.

Asialoglycoproteins↗
PubMed1992

Determination of nicotinamide and pyridoxine in an elemental diet by column-switching high-performance liquid chromatography with UV detection.

The determination of nicotinamide and pyridoxine in an elemental diet containing 46 compounds was performed by column-switching high-performance liquid chromatography with UV detection at 260 and 290 nm, respectively. The method is simple, rapid, sensitive and reproducible. The calibration graphs for the two vitamins were linear in the ranges 0-0.2 and 0-0.015 micrograms, respectively. The recoveries of both vitamins by the standard addition method were over 95%. There was good agreement between the concentrations indicated and found for both vitamins.

Chromatography, High Pressure Liquid↗
PubMed1992

Determination of ascorbic acid in elemental diet by high-performance liquid chromatography with electrochemical detection.

Determination of ascorbic acid in a multi-component elemental diet was performed by high-performance liquid chromatography with electrochemical detection. This method is suitable for the routine determination of ascorbic acid in elemental diet because it is simple, rapid, sensitive, highly selective and reproducible. The calibration graph of ascorbic acid was linear in the range 0-1.0 micrograms. The recovery of ascorbic acid was over 95% by the standard addition method. There was good agreement between the concentrations of ascorbic acid stated and found.

Ascorbic Acid↗
PubMed1992

Ultramicrodetermination of cyanocobalamin in elemental diet by solid-phase extraction and high-performance liquid chromatography with visible detection.

The ultramicrodetermination of cyanocobalamin (9 ng/g) in elemental diet containing 46 kinds of compounds, with concentrations at least 50-10(6) times higher than that of cyanocobalamin, was performed by Sep-Pak C(18) purification and concentration of cyanocobalamin followed by HPLC with detection at 550 nm. The method is simple, rapid, sensitive and reproducible. The calibration graph was linear in the range of 0-0.2 micrograms. The recovery of cyanocobalamin was over 95% by the standard addition method. There was good agreement between the cyanocobalamin concentrations indicated and found.

Chromatography, High Pressure Liquid↗
PubMed1992

Isolation and partial characterization of serine- and threonine-rich porcine gastric mucus glycopeptides.

1. Two subfractions from purified porcine gastric mucus glycopeptide were found to separate from each other by cesium chloride equilibrium centrifugation. The highest density fraction and two lower density fractions separated were designated VHD, HD and LD, respectively. A comparative study of these components was made. 2. The high and low density fractions, HD and LD, appeared almost the same or identical, while VHD differed completely from either of them in the following respects: (1) VHD exhibited strong alcian blue binding activity. (2) 57% of VHD bound to the DEAE-Toyopearl column equilibrated with 0.2 M NaCl. (3) VHD eluted from the Sephacryl S-400 column as a lower molecular subunit. (4) One third of the sialic acid as a minor component in VHD was constituted by N-glycolylneuraminic acid. (5) Carbohydrate composition showed typical mucus glycoprotein with slightly higher fucose content. (6) Amino acid compositions of the anionic components prepared from VHD showed the highest Ser/Thr ratio, 1.92 compared to 0.46 for LD and 0.62 for HD. (7) Oligosaccharide released from VHD by alkaline-sodium borohydride treatment was larger than that from HD or LD. 3. The above results indicate the minor component, VHD, separated from the major components, to be a quite similar but not identical component to the so-called sulfated mucus glycoprotein reported previously [Slomiany et al. (1972) J. biol. Chem. 247, 5062-5070].

Alcian Blue↗
PubMed1992

Analysis of porcine gastric mucus glycoprotein added to a culture medium of Streptomyces sp. OH-11242 as the only source of carbon.

1. In the process of obtaining the degradation enzymes of mucus glycoprotein, porcine gastric mucus glycoprotein (PGM), added as the only source of carbon, was removed from the culture medium of Streptomyces sp. OH-11242 [Iwase et al. (1988) Biochem. biophys. Res. Commun. 151, 422-428] and analysed. 2. The amino acid and carbohydrate compositions of porcine gastric mucus glycoprotein (PGM-m) recovered from a culture medium were similar to those of original PGM. 3. However, the elution profile of PGM-m on Sephacryl S-400 differed from that of PGM and closely resembled that of performic acid-treated PGM or protease-treated PGM. 4. Either of these corresponded to the so-called subunit of approximately 550,000 in mol. wt, as reported by Scawen and Allen [(1977) Biochem. J. 163, 363-368]. 5. Performic acid treatment of PGM-m led to the production of a smaller unit (unit m) having a mol. wt of about 72,000. Separate treatment of different sized components prepared from PGM-m showed the above unit m to be produced from each molecule. 6. Thus, PGM-m is a molecule partly modified by various glycosidases including endo-alpha-N-acetylgalactosaminidase and exposure of the modified part to performic acid results in oxidation. 7. Production of unit m from both larger and smaller molecules indicates the part susceptible to performic acid to exist at regular intervals on the mucus glycoprotein molecule.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1992

Analysis of glycoform of O-glycan from human myeloma immunoglobulin A1 by gas-phase hydrazinolysis following pyridylamination of oligosaccharides.

A comparative study was made on the glycoform of O-glycan from human myeloma immunoglobulin A1. By gas-phase hydrazinolysis, O-glycan was released from its hinge portion. The released oligosaccharide was pyridylaminated and separated by a two-dimensional analytical method of gel filtration and reverse-phase HPLC. Four major pyridylamino derivatives (P1-P4) were obtained. The neutral component (P4) among them was identified as Gal beta 1,3GalNAc-PA by cochromatography with an authentic standard pyridylamino sugar. The desialylation of the other components indicated the largest P1 and middle size P2 components possibly corresponded to a disialylated structure, NeuAc alpha 2,3Gal beta 1,3(NeuAc alpha 2,6)GalNAc-PA, and a monosialylated component, NeuAc alpha 2,3Gal beta 1,3GalNAc-PA, respectively. The structural assignment of P3 is still incomplete. Four similar components were also detected in bovine fetuin whose relative content (P1:P2: P3:P:4) was 16:43:19:22. The relative content (%) of P1-P4 (glycoform) in IgA1 from the healthy control was 10.1 +/- 3.3, 48.2 +/- 4.6, 7.0 +/- 2.6, and 34.7 +/- 4.5. The glycoform of O-glycan on IgA1 thus appears the same for any individual. Analysis of IgA1 myeloma protein indicated glycoforms distinct from those of the healthy controls. The relative content of these component could be classed as 2:8:0:90 (Type I, only one case designated as Kita), 5:24:3:68 (Type II, seven cases), and 9:41:5:45 (Type III, four cases). Thus, the results for IgA1 myeloma protein indicate that at least three glycoforms of O-glycan are possible for the IgA1 hinge structure. However, only one glycoform was found in the healthy controls.

Amination↗
PubMed1992

Estrogen receptor, c-erbB-2 and nm23/NDP kinase expression in the intraductal and invasive components of human breast cancers.

Expression of the c-erbB-2 oncoprotein (ErbB-2) and the nm23 anti-metastatic gene product (nucleoside diphosphate [NDP] kinase) was examined in the intraductal and invasive components of 63 fresh human breast cancer tissues. The expression of estrogen receptor (ER) as a marker of hormone dependency and the Ki-67 protein as a proliferative cell marker was also examined. ErbB-2 and ER were positive in 77.8% (28/36) and 64.7% (22/34) of the intraductal components, and in 43.6% (27/62) and 57.1% (36/63) of the invasive components, respectively. NDP kinase was positive in 58% (18/31) of intraductal, and in 30.9% (17/55) of invasive areas. The average Ki-67-positive cell rates were 5.9% in the intraductal, and 10.7% in the invasive components. Thus, the cells within the intraductal component of breast cancer appear to have different characteristics from the invasive component, not only in markers of proliferative ability, but also in the expression of oncogenes and hormone receptors.

Biomarkers, Tumor↗
PubMed1991

Primary adrenocortical tumors in autopsy records--a survey of "Cumulative Reports in Japan" from 1973 to 1984.

All cases of primary adrenocortical tumors, including those found incidentally, recorded in the Pathological Autopsy Case Annuals of Japan during a 12 year period from 1973 to 1984 were surveyed. Age- and sex-specific incidences of lesions were estimated from the population, mortality and autopsy statistics for the same period. There were 101 adenomas, 77 of which were presumed to be non-functional, and 222 carcinomas. The age-specific distribution profiles of both the benign and malignant tumors showed single peaks in the sixties and could not be distinguished from one another. The estimated age-specific distribution of morbidity of the non-functional adenomas showed a peak at about 10 years younger than that found in the autopsy records, although it was again similar to that of carcinoma derived from various clinical reports. The morbidity of the non-functional adenomas per 100,000 population was almost equal to that of breast cancer in Japan, being highest in the fifties age group with more than 4,000 people a year being suggested to have adenoma in this age bracket.

Adenoma↗
PubMed1990

Extraction method for preparing pyridylamino sugar derivatives and application to porcine gastric mucus glycoprotein analysis.

For the sensitive detection of free sugars and oligosaccharides, the use of their pyridylamino derivatives has now found general acceptance. To remove excess 2-aminopyridine from this derivative in a reaction mixture, gel filtration and ion-exchange chromatography were conducted. It was found in the present study that contaminated 2-aminopyridine could be selectively removed from the reaction mixture by adjusting the pH with saturated sodium bicarbonate at above 8.5 followed by extraction with benzene. By using this method, fewer purification steps and less time are required, with minimum loss of pyridylamino sugar derivatives.

Amino Sugars↗
PubMed1990

Gradual increases in marginal leakage of resin composite restorations with thermal stress.

The effects of thermal stress on the marginal leakage of resin composite restorations in bovine teeth were investigated by a method that preserved the specimens. The changes in marginal leakage of specimens with increasing numbers of thermal cycles were measured by an electrical conductivity method. Four brands of posterior resin composites were used to fill cylindrical cavities (2.0 mm in diameter and 1.5 mm in depth) on the labial surfaces of bovine incisors, according to the manufacturer's instructions. Thermal cycling stress was applied to the specimens for up to about seven weeks (9000 cycles). During this time, the electrical conductance between the pulp and a drop of physiological saline solution covering the resin restoration was measured periodically by application of an electrical potential (60 Hz, 10 Vp-p). Thermal stress increased the marginal leakage gradually, rather than step-wise. Even before application of any thermal stress, wide variations of marginal leakage were found among different specimens restored with the same brand of resin. Specimens with less initial leakage showed less increase in leakage, and vice versa, throughout the experimental period.

Animals↗
PubMed1989

The clinical value of serum CA15-3 assay postoperatively in breast cancer patients.

Serum carbohydrate antigen (CA15-3) values were examined in 300 normal subjects in order to determine the standard value of this antigen. The clinical relevance of repeatedly assaying this marker in patients with or without recurrent breast cancer postoperatively was compared with assaying the serum carcinoembryonic antigen (CEA) values. The upper limit of CA15-3 was calculated as being 25.3 U/ml in the normal subjects and the distributions of CA15-3 values were not markedly different among the normal subjects, even if they had been selected according to sex or age. Moreover, no differences were observed among normal women who had been randomly selected according to the age distribution of the breast cancer patients. Thirty samples taken from the breast cancer patients postoperatively revealed values of higher than 25 U/ml and 73 samples showed lower levels. The serum CEA values were positive in 16 samples and negative in 85 samples. Although the accuracy of the CEA assay was about 10 per cent higher than that of the CA15-3 assay, its low positive rate was unsatisfactory for effective use in the breast clinic. The results of this study suggest that serum CA15-3 is not detectable unless there is a relatively large number of tumor cells. The higher false positive rate of the CA15-3 assay should therefore be considered as suggesting recurrence.

Adult↗
PubMed1989

[Imaging diagnosis of ruptured site in hepatocellular carcinoma].

Rupture causes frequently the patients with HCC to death. Then it is important to investigate ruptured site of HCC in order to stop bleeding effectively and safely by emergent TAE without causing liver failure. We evaluate the usefulness of 3 major imaging method, such as US, CT and angiography in our 18 cases of HCC. In ultrasonography, ruptured site was shown as the high echoic area localized around the tumor in 4/15 cases (26.7%). In computed tomography of rapid scanning, it was shown as the intraperitoneal high density area around the tumor in 3/18 cases (16.7%). And lipiodol CT showed the characteristic leakage in the abdominal cavity. In angiography, it was shown as the extravasation of contrast material only in 2/13 cases (15.4%). In the results, it was possible to diagnose the ruptured site in 8/18 cases (44.4%) by using these procedures. Diagnosis of ruptured site will make it possible to reduce the frequency of hepatic failure caused by emergent TAE.

Adult↗
PubMed1988

Release of oligosaccharides possessing reducing-end N-acetylgalactosamine from mucus glycoprotein in Streptomyces sp. OH-11242 culture medium through action of endo-type glycosidase.

A crude enzyme preparation from a culture medium of Streptomyces sp. OH-11242 contained endo-alpha-N-acetylgalactosaminidase activity. The activity could be induced by the addition of purified porcine gastric mucin to the culture medium. Oligosaccharides corresponding to approximately 2-14 glucose units were detected in the culture medium and also in an incubated reaction mixture of crude enzyme preparation and mucus glycoprotein. The resulting product with N-acetylgalactosamine at the reducing terminal implied the presence of a new type of endo-glycosidase liberating not only Gal beta 1-3GalNAc but also other larger oligosaccharides by hydrolysis of the O-glycosidic linkage between GalNAc and Ser (Thr).

Animals↗