Biomedical subjects

Keisuke Matsumoto

Publications and source records attributed to Keisuke Matsumoto.

8 recordsLinked to original sources

PubMed2005

Identification, cloning, and characterization of a Sporobolomyces singularis beta-galactosidase-like enzyme involved in galacto-oligosaccharide production.

Sporobolomyces singularis can be used as a biocatalyst in galacto-oligosaccharide production. We isolated 2-deoxy-D-glucose-resistant mutants of S. singularis ATCC 24193 and recovered a mutant that showed 10-fold higher beta-galactosidase-like activity than the parent strain and which was insensitive to catabolite repression. Thereafter, the beta-galactosidase-like enzyme was purified from the mutant and revealed to be a glycoprotein with both beta-glucosidase- and beta-galactosidase-like activity, the Michaelis-Menten constants of which for o-nitrophenyl-beta-D-galactopyranoside and p-nitrophenyl-beta-D-glucopyranoside were 5.40 and 1.96 mM, respectively, and the maximum velocities were 3.07 and 2.30 micromol/min per mg of protein, respectively. Its molecular mass was estimated to be 73.9 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis and 146 kDa by gel filtration, suggesting that it has a homodimeric structure. We sequenced the N-terminus and internal peptides of this protein and isolated both a cDNA and a gene with degenerate primers. The gene, named bg l A, has 18 introns and 19 exons and encodes a polypeptide of 594 amino acids. The Bg l A protein was approximately 35% identical and 50% similar to plant beta-glucosidases belonging to family 1 glycosyl hydrolases, but with a unique 110-amino-acid sequence at the N-terminus. The beta-galactosidase-like enzyme (i.e., Bg l A protein) in S. singularis is a beta-glucosidase with high transgalactosidase activity.

Amino Acid Sequence↗

PubMed2004

Improved separation method for highly purified lutein from Chlorella powder using jet mill and flash column chromatography on silica gel.

We investigated an improved method for the separation of high-purified lutein from a commercially available spray-dried Chlorella powder (CP) using fine grinding by jet mill and flash column chromatography on a silica gel. Saponification and extraction of lutein were enhanced 2.3-2.9-fold in jet mill-treated CP (mean particle size, 20 microm) as compared to untreated CP (mean particle size, 67 microm). The carotenoid extract was dissolved in ether-hexane (1:1 v/v) and subjected to flash column chromatography on silica gel. A mixture of alpha- and beta-carotene was eluted with hexane, followed by elution with hexane-acetone-chloroform (7:2:1 v/v). Lutein (dark-orange band) was collected after the elution of an unknown colorless compound (detected based on UV absorbance). The purity of lutein in this fraction was over 99%, and the yield was 60%. The present study provides key information for obtaining highly purified lutein using flash column chromatography on a silica gel.

Chlorella↗

PubMed2004

Effect of a gamma-aminobutyric acid-enriched dairy product on the blood pressure of spontaneously hypertensive and normotensive Wistar-Kyoto rats.

We investigated the blood-pressure-lowering effects of gamma-aminobutyric acid (GABA) and a GABA-enriched fermented milk product (FMG) by low-dose oral administration to spontaneously hypertensive (SHR/Izm) and normotensive Wistar-Kyoto (WKY/Izm) rats. FMG was a non-fat fermented milk product produced by lactic acid bacteria, and the GABA contained in FMG was made from the protein of the milk during fermentation. A single oral dose of GABA or FMG (5 ml/kg; 0.5 mg GABA/kg) significantly (P<0.05) decreased the blood pressure of SHR/Izm from 4 to 8 h after administration, but did not increase that of WKY/Izm rats. The hypotensive activity of GABA was dose-dependent from 0.05 to 5.00 mg/kg in SHR/Izm. During the chronic administration of experimental diets to SHR/Izm, a significantly slower increase in blood pressure with respect to the control group was observed at 1 or 2 weeks after the start of feeding with the GABA or FMG diet respectively (P<0.05) and this difference was maintained throughout the period of feeding. The time profile of blood-pressure change due to administration of FMG was similar to that of GABA. FMG did not inhibit angiotensin 1-converting enzyme. Furthermore, an FMG peptide-containing fraction from reverse-phase chromatography lacked a hypotensive effect in SHR/Izm rats. The present results suggest that low-dose oral GABA has a hypotensive effect in SHR/Izm and that the hypotensive effect of FMG is due to GABA.

Administration, Oral↗

PubMed2004

Magnetic sense in the Japanese eel, Anguilla japonica, as determined by conditioning and electrocardiography.

Magnetosensitivity of the Japanese eel, Anguilla japonica, was examined by conditioning and electrocardiography. Marine eels, river eels and farmed eels were conditioned to an imposed magnetic field ranging from 12,663 nT to 192,473 nT parallel to the fish body, which was placed along the earth's west-east axis. Electrocardiograms were recorded with electrodes placed close to the fish body inside a PVC pipe shelter. After 10-40 conditioning runs, all the eels exhibited a significant conditioned response (i.e. slowing of the heart beat) to a 192,473 nT magnetic field and even to a 12,663 nT magnetic field, respectively equivalent to 5.92x and 0.38x the horizontal geomagnetic field (32,524 nT) at our laboratory. The west-east vector of the imposed magnetic field (12,663 nT) combined with that of the geomagnetic field and produced a horizontal resultant magnetic field of 21 degrees easterly. Therefore, Japanese eel are magnetosensitive whether they are at sea, in the river or in the farm. Results of the present study were compared with those of past studies that showed no magnetic sense in the American eel, Anguilla rostrata, and the European eel, Anguilla anguilla.

Anguilla↗

PubMed2004

[Application of the JJ1017 code to master-table of RIS database].

We are developing an open-type Radiology Information System (RIS) under the project name KPECK. Part of the RIS has already been employed in Kouri Hospital of Kansai Medical University. The RIS is based on a database of the history of clinical study and exposure. We tried using the JJ1017 (ver1.0) code for the master-table of the database. The JJ1017 code, which is standardized by JIRA and JAHIS, is used in communicating information between the RIS and medical modalities. Through construction of the database, we found a technique by which the JJ1017 code could be applied to its master-table. In coordinating the JJ1017 code with the master-table of the database, we extended various study codes and systematically coordinated them with the architecture of the database.

Database Management Systems↗

PubMed2003

Microsatellite instability and loss of heterozygosity in the nondysplastic colonic epithelium of ulcerative colitis.

Background. A major longterm risk for patients with ulcerative colitis (UC) is the development of colorectal dysplasia and cancer. Microsatellite instability (MI) has now been reported not only in colitic cancers but also in dysplasias, and even in nondysplastic inflamed mucosa. With the conventional microdissection technique, however, contamination by nonepithelial cells cannot be prevented and this could produce less reliable results than other methods. Therefore, we examined the condition of MI and loss of heterozygosity (LOH) of UC epithelium using a crypt isolation technique. Methods. One hundred and twenty-nine biopsy samples from 21 patients with UC were investigated for histology and microsatellite status, using nine microsatellite markers. A total of 1031 polymenase chain reaction (PCR) products were evaluated. Results. We found that no microsatellite markers displayed instability, but LOH at the 3p locus was detected in the nondysplastic epithelium of one patient with longstanding UC. Conclusions. Our study strongly suggests that MI does not contribute to the progression of the colitis-dysplasia sequence.

Adolescent↗

PubMed2003

Hla-B genotype in Japanese patients with Crohn's disease.

PURPOSE: The HLA-B gene is one of the susceptibility genes for inflammatory bowel disease. Previous association studies of HLA-B showed several associated alleles and haplotypes of HLA-B in patients with ulcerative colitis, and among the associated alleles HLA-B*52 is well known to be strongly associated with ulcerative colitis in Japanese patients. However, there are no convincing reports about HLA-B including the B*52 allele in patients with Crohn's disease. The purpose of this study was to determine if HLA-B, especially the B*52 allele, confers susceptibility to Crohn's disease or determines the disease phenotype of Crohn's disease. METHODS: A total of 195 patients with Crohn's disease (49 ileitis, 106 ileocolitis, 34 colitis, 6 uncertain) and 185 healthy controls were studied in this case-controlled study. All patients and healthy controls were Japanese. Genotyping of the HLA-B gene was performed by a polymerase chain reaction, sequence-specific primer that can classify the gene into 23 allele groups. Allele frequencies were compared between patients with Crohn's disease and healthy controls with chi-squared test using a 2 x 2 contingency table. P value was corrected by the number of allele groups (n = 23) observed in the Japanese population or the number of clinical subgroups. Corrected P values of <0.05 were considered to be statistically significant. RESULTS: Before the correction for multiple testing, B*4001 and B*44 were associated with patients with Crohn's disease, positively and negatively, respectively. However, after the correction there were no significant differences in any HLA-B alleles between patients with Crohn's disease and healthy controls. In the subgroup analysis according to clinical phenotypes (disease location, anal lesion, age at diagnosis, need for surgery), none of the HLA-B alleles except B*52 showed any disease phenotype-genotype associations. The allele frequency of B*52 in the colitis type (16.2 percent; corrected P = 0.011) was significantly higher than that in the combined group of the ileitis (7.1 percent) and ileocolitis (5.2 percent) types. CONCLUSIONS: These results demonstrated that HLA-B did not confer overall susceptibility to Crohn's disease in Japan, but the B*52 allele may affect the location of the disease.

Adult↗

PubMed2003

Antioxidant and anti-cataract effects of Chlorella on rats with streptozotocin-induced diabetes.

The antioxidant activities of Chlorella in vitro and in vivo were investigated. Chlorella showed a strong antioxidant effect compared to various vegetables in a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. To evaluate the antioxidant and anti-cataract effects in vivo, a 7.3% Chlorella powder was fed to rats with streptozotocin-induced diabetes for 11 wk. At the end of the experiment, Chlorella had decreased the blood glycated hemoglobin (hemoglobin A1c) and serum cholesterol levels significantly, however, it had not affected the serum glucose concentration. The serum lipid peroxide value (TBARS value) in the rats fed Chlorella was lower than that of the control rats. In the liver and kidney, Chlorella also reduced chemiluminescent intensities. In addition, it delayed the development of lens opacities. The lens lipid peroxide content of the rats fed Chlorella was lower than that of the control rats, however the differences were not significant. These results indicate that Chlorella has antioxidant activity and may be beneficial for the prevention of diabetic complications such as cataracts.

Animals↗