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M Kato

Publications and source records attributed to M Kato.

At least 955 records · Page 53Linked to original sources
PubMed1996

Acid xylanase from yeast Cryptococcus sp. S-2: purification, characterization, cloning, and sequencing.

A xylan-degrading enzyme produced by yeast Cryptococcus sp. S-2 was isolated and purified, and characterized as an endoxylanase (1,4-beta-D-xylan xylanohydrolase [EC 3.2.1.8]). We estimated the molecular weight and isoelectric point of purified xylanase (xyn-CS2) to be 22,000 and 7.4, respectively. This low-molecular-weight xylanase had an unusual pH optimum of 2.0, and showed 75% of maximal activity even at pH 1.0. An open reading frame of the cDNA specified 209 amino acids, including a putative signal peptide of 25 amino acids. The deduced amino acid sequence of xyn-CS2 shared significant similarities with the family-G xylanases of B. pumilus, C. acetobutylicum, T. reesei, and A. kawachii. Xyn-CS2 included two unique cysteine residues in a putative catalytic region, raising the possibility that these residues are at least partially responsible for its acidophilic nature.

Amino Acid Sequence↗
PubMed1996

Gene analysis of trehalose-producing enzymes from hyperthermophilic archaea in Sulfolobales.

The genes encoding new trehalose-producing enzymes from S. acidocaldarius ATCC33909 were cloned to analyze the distribution of these genes in Sulfolobales. Comparison of the amino acid sequences with S. solfataricus KM1 showed approximately 50% similarity. Southern analysis suggest that homologues of the trehalose-producing enzyme genes exist widely in sulfolobales and strains in Sulfolobales were classified into three kinds of genotypes.

Amino Acid Sequence↗
PubMed1996

Sequence-specific binding sites in the Taka-amylase A G2 promoter for the CreA repressor mediating carbon catabolite repression.

The N-terminal part of the CreA protein encompassing two zinc fingers was expressed in Escherichia coli as a fusion protein with the maltose binding protein (MalE) of E. coli. Our results show that CreA binds to the promoter of the Taa-G2 gene encoding Taka-amylase A of Aspergillus oryzae. DNase I footprinting experiments showed that CreA bound to three sites with high affinity and to one site with low affinity within the first 401-bp region upstream of the transcription initiation site. All of the sites contained sequences related to the CreA consensus binding site (5'-SYGGRG-3'), and are suggested to participate in repression of the Taa-G2 gene in response to glucose.

Amino Acid Sequence↗
PubMed1996

Gene cloning and expression of new trehalose-producing enzymes from the hyperthermophilic archaeum Sulfolobus solfataricus KM1.

The genes encoding for trehalose-producing enzymes, a glycosyl-trehalose-producing enzyme (glycosyltransferase) and a gylcosyl-trehalose-hydrolyzing enzyme (alpha-amylase), from Sulfolobus solfataricus KM1 were cloned and expressed in E. coli. The nucleotide sequence of the glycosyltransferase gene and the alpha-amylase gene indicated proteins with lengths of 728 and 558 amino acids and molecular masses of 86-kDa and 65-kDa, respectively. Regions highly conserved in the alpha-amylase family exist in the amino acid sequences of these enzymes.

Amino Acid Sequence↗
PubMed1996

Purification and characterization of new trehalose-producing enzymes isolated from the hyperthermophilic archae, Sulfolobus solfataricus KM1.

Amylolytic activity that converts soluble starch to alpha, alpha-trehalose (trehalose), was found in the cell homogenate of the hyperthermophilic acidophilic archae, Sulfolobus solfataricus KM1. DEAE chromatography of the homogenate as well as other new reliable assay methods showed two enzymes to be essential for this activity. These enzymes, a glycosyltransferase and an amylase, were purified to homogeneity and characterized. Their molecular masses were 76 kDa and 61 kDa and activities were maximal at 70-80 degrees C and 70-85 degrees C, respectively. High thermostability was noted for each. The reaction products by the two enzymes on maltooligosaccharides were identified by 1H- and 13C-NMR spectra and HPLC analysis. The cooperative mechanism of the two enzymes was used in a new enzymatic pathway for trehalose synthesis from starch.

Amylases↗
PubMed1996

[Reproductive and developmental toxicity study of a new antineoplastic agent, S-1 (IV)--Perinatal and postnatal study in rats by oral administration].

S-1 is a newly developed antineoplastic agent consisting in a molar ratio of 1:0.4:1 mixture of tegafur (FT), 5-chloro-2, 4, dihydroxypyridine (CDHP) and potassium oxonate (Oxo) was administered orally to SD rats at doses of 0, 1, 4 and 7 mg/kg/day (as a dose of FT) during the perinatal and postnatal periods to examine its effect on dams and postnatal growth of the offspring. A group as the control was treated only with medium (0.5% hydroxypropyl methylcellulose) solution. The administration of 7 mg/kg/day to dams caused suppression in body weight gains and in food consumption during the treatment period. No adverse effects of S-1 on the length of gestation, gestation index, delivery and nursing ability were found. The administration of 4 and 7 mg/kg/day caused suppression in body weight gains in offspring of both sexes. Significant decrease in kidney weights were observed in females of the 4 mg/kg/day group and in both sexes of the 7 mg/kg/day group. No adverse effects of S-1 were found in number of live offspring at birth, sex ratio of live offspring, number of dead offspring at birth, birth index, viability index, weaning index, incidence of external anomalies, general conditions, postnatal development, reflex responses, motor coordination, emotional behavior, learning ability, skeletons, necropsy findings or reproductive functions. No adverse effects of S-1 on F2 offspring were found in any treatment groups. Under the conditions of the present study, the non-observed effect dose levels of S-1 was 4 mg/kg/day for general toxicology of dams, 7 mg/kg/day for reproductive ability of dams, 1 mg/kg/day for postnatal growth in F1 offspring and 7 mg/kg/day for postnatal growth in F2 offspring.

Administration, Oral↗
PubMed1996

Improvement of hemolysis in muscle phosphofructokinase deficiency by restriction of exercise.

A 29-year-old woman with muscle phosphofructokinase (PFK) deficiency had exercise intolerance, painful cramps, elevation of muscle enzyme levels in the serum and compensated hemolysis. After the restriction of exercise, the creatine kinase level and indirect bilirubin level decreased, and the reticulocyte count and haptoglobin level were normalized. It is suggested that the hemolysis which was accelerated by exercise was improved by restriction of exercise.

Adult↗
PubMed1996

Cardiac angiosarcoma.

Angiosarcoma is one of the most common cardiac tumors, but early detection of this tumor is often difficult, as exemplified by our patient, a 55-year-old woman whose cardiac tumor was first detected by echocardiography. Surgical removal of the tumor was impossible due to its extensive pericardial invasion. Pathological diagnosis was not complete before autopsy because of the wide occupied necrotized area of the tumor. There is no diagnostic imaging technique available to detect such a necrotized area. An imaging technique more powerful than echocardiography and able to diagnose angiosarcoma earlier is needed.

Biopsy↗
PubMed1996

Impaired endothelium-dependent vasodilation of coronary resistance vessels in hypercholesterolemic patients.

To determine the relationship between hypercholesterolemia and the endothelial function of coronary resistance vessels, we studied the changes in coronary blood flow (CBF) in response to acetylcholine, an endothelium-dependent vasodilator, and adenosine, an endothelium-independent vasodilator, in patients with hypercholesterolemia (n = 17) and in control patients (n = 17). All patients had normal epicardial coronary arteries. Serial 2-min infusions of acetylcholine, at 3 micrograms/min and 30 micrograms/min, caused a dose-dependent increase in CBF in each group. The acetylcholine-induced maximal increases in CBF were inversely correlated with the serum cholesterol level (r = -0.55, p < 0.01), and were significantly smaller in the hypercholesterolemic patients than in control patients. However, the adenosine-induced increases in CBF were similar in the two groups. These results suggest that the endothelium-dependent vasodilation of resistance vessels is lessened in patients with hypercholesterolemia even before the formation of atherosclerotic stenotic lesions in epicardial coronary arteries, and that hypercholesterolemia impairs endothelium-dependent vasodilation of coronary resistance vessels.

Acetylcholine↗
PubMed1996

Value of three-dimensional spiral CT hepatic angiography.

OBJECTIVE: The aim of this study was to compare with conventional angiography images the diagnostic utility of three-dimensional CT hepatic angiography (CTHA) images reconstructed from spiral CT images obtained during direct injection of contrast material into hepatic arteries. MATERIALS AND METHODS: Three-dimensional CTHA images were reconstructed from spiral CTHA images obtained during direct hepatic arterial contrast material injection in 22 patients. We used maximum-intensity-projection (MIP) and shaded-surface-display (SSD) techniques. We compared matched pairs of MIP CTHA images and SSD CTHA images with conventional angiograms for depiction of peripheral (segmental to subsegmental order branches) and proximal (common to proper) hepatic arteries as well as for conspicuity of the entire hepatic arterial tree in 22 patients and for conspicuity of tumors, recognition of tumor sites, and depiction of tumor-feeding arteries in 21 patients with malignant liver tumors. Our evaluations were performed in a blinded fashion by two experienced radiologists, who reached a consensus. (These radiologists also counted the number of tumors depicted by each method in the 21 patients with malignant liver tumors.) RESULTS: Depiction of peripheral and proximal hepatic arteries and conspicuity of the entire hepatic arterial tree were significantly better on conventional angiograms than on MIP CTHA images and SSD CTHA images. Conspicuity of tumors and recognition of tumor sites were significantly better on MIP CTHA images and SSD CTHA images than on conventional angiograms. Depiction of tumor-feeding arteries was significantly better on MIP CTHA images than on SSD CTHA images and conventional angiograms. For 47 malignant liver tumors, MIP CTHA images showed 40 (85%), SSD CTHA images showed 34 (72%), and conventional angiograms showed 20 (43%). CONCLUSION: MIP CTHA images showed liver tumors, tumor sites, and tumor-feeding arteries better than conventional angiograms. MIP was the preferred method for three-dimensional CTHA analysis.

Aged↗
PubMed1996

Treatment with recombinant interferon-alpha 2a for patients with chronic hepatitis C: predictive factors for biochemical and virologic response. Osaka Liver Disease Study Group.

BACKGROUND: The heterogeneity of the hepatitis C virus (HCV) genome has been reported to be associated with the effectiveness of interferon therapy. We investigated the correlation of the viral and host factors, including the degree of sequence complexity of the HCV genome for responses to interferon-alpha in patients with chronic hepatitis C. METHODS: Ninety-seven patients received a 26-week course of recombinant interferon-alpha 2a therapy. The sequence complexity of the envelope 1-2 region was evaluated by polymerase chain reaction-mediated single-strand conformation polymorphism (PCR-SSCP) analysis. RESULTS: Of the 85 patients who completed the treatment, 31 (36%) achieved a sustained response, and 28 (33%) showed a sustained loss of HCV RNA. A low HCV RNA level, determined by the branched DNA probe assay, and serotype group 2 HCV correlated with a sustained response. In patients with serotype group 1 HCV of more than the threshold of the branched DNA probe assay, a band number on PCR-SSCP analysis of more than 2 could be associated with inefficacy of interferon therapy. Multivariate analysis in the 50 patients whose sera were available for all the virologic tests showed that only the HCV RNA level is independently predictive of a sustained response. CONCLUSIONS: Determination of the HCV RNA level is most important for predicting the response before interferon therapy. PCR-SSCP analysis may be useful as an additional test for patients with a high HCV RNA level of serotype group 1 HCV.

Adult↗
PubMed1996

Expression of TGF-beta type I and type II receptors in rat eyes.

Transforming growth factor beta (TGF-beta) transduces signals through mediation of type I and type II serine/threonine kinase receptors. The expression of TGF-beta type I (T beta R-I) and II (T beta R-II) receptors in rat eyes was investigated immunohistochemically. T beta R-I and T beta R-II immunoreactivity was detected in corneal and conjunctival epithelial cells, corneal endothelial cells, ciliary epithelial cells, lens epithelial cells, retinal pigment epithelial cells, and choroidal vessels. This co-expression of T beta R-I and T beta R-II indicates that the above cells respond to TGF-beta and, because TGF-beta is reported to be produced in ocular tissues, that it may have important autocrine and/or paracrine roles in the growth and metabolism of ocular tissues in situ.

Activin Receptors, Type I↗
PubMed1996

Coronary segmental responses to acetylcholine in patients with hypercholesterolemia.

We investigated coronary segmental response to intracoronary acetylcholine (ACh) in 19 patients with hypercholesterolemia and 18 patients with normal cholesterol levels. All patients had atypical and chest pain and angiographically normal coronary arteries. After baseline angiography, ACh (3 and 30 micrograms/min) was infused into the left coronary artery, followed by infusion of nitroglycerin. Percent changes in diameter of the proximal, middle, and distal segments of the left coronary arteries were measured by quantitative angiography. In the normocholesterolemic group, 3 micrograms/min of ACh produced significant coronary vasodilation in the distal segments (+8.2 +/- 2.6%, p < 0.005), while 30 micrograms/min did not cause any changes. In the hypercholesterolemic group, 30 micrograms/min of ACh caused significant coronary vasoconstriction in the middle and distal segments (-7.2 +/- 1.9% and -6.2 +/- 1.9%, p < 0.001 and p < 0.01, respectively), while 3 micrograms/min caused no changes. In each group, vasodilator responses to nitroglycerin in the middle and distal segments were significantly greater than those in the proximal segments (p < 0.001). Our results suggest that impaired endothelial function may be evaluated more effectively in the distal coronary segments in patients in the early stage of epicardial coronary atherosclerosis attributable to hypercholesterolemia.

Acetylcholine↗
PubMed1996

[A case of superior vena cava syndrome treated with combination radiation and CRE (CBDCA and VP-16) therapy].

Carboplatin and etoposide were reported to be excellent radiation sensitizers. We encountered a patient with SVC syndrome due to lung cancer who was successfully treated by combination carboplatin, etoposide and hyperfractionation radiotherapy. A 72-year-old man was admitted to our hospital because of remarkable face edema. Computed tomography revealed a huge lung tumor and compressed SVC due to tumor growth. Acute tumor regression was essential for this case. We performed combination chemotherapy and radiation. The regime consisted of CBDCA 300 mg (day 1 1 hr drip infusion) and etoposide 50 mg/day for 21 days by oral administration. Two daily fractionations of 1.4 Gy were delivered 5 days-a-week, with a 4 h interval between fractions (total dose 49.8 Gy). Complete response of huge tumor was attained in this case. The major side effect associated with the therapy was myelosuppression. The patient's quality of life has been remarkably improved with this therapy.

Aged↗