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Satoshi Kaneko

Publications and source records attributed to Satoshi Kaneko.

65 records · Page 4Linked to original sources
PubMed2002

Crystallization and preliminary X-ray crystallographic studies of rice alpha-galactosidase.

alpha-Galactosidases catalyze the hydrolysis of galactooligosaccharides and galactopolysaccharides to alpha-galactose residues and are widely distributed in microorganisms, plants and animals. alpha-Galactosidase from rice (Oryza sativa L. ssp. japonica) was crystallized by the hanging-drop vapour-diffusion method. The crystals belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 63.1, b = 71.3, c = 85.6 A, and diffract beyond 1.9 A resolution.

Crystallization↗
PubMed2002

Positive feedback regulation between Akt2 and MyoD during muscle differentiation. Cloning of Akt2 promoter.

Akt2 is a member of the Akt/PKB family, which is involved in a variety of cellular events including cell survival, proliferation, and differentiation. During skeletal muscle differentiation, the Akt2 but not Akt1 expression was significantly increased. Microinjection of anti-Akt2 but not anti-Akt1 antibody efficiently abrogated myogenesis, indicating that Akt2 plays a specific role in muscle differentiation. It has been well documented that ectopic expression of MyoD is sufficient to induce muscle differentiation in myoblasts. However, the mechanism of induction of Akt2 during muscle differentiation and the significance of Akt2 protein in MyoD-induced myogenesis are largely unknown. In this study, we provide direct evidence that Akt2 is transcriptionally regulated by MyoD and activates MyoD-myocyte enhancer binding factor-2 (MEF2) transactivation activity. The Akt2 promoter was isolated and found to contain nine putative E-boxes (CANNTG), which are putative MyoD binding sites. Electrophoretic mobility shift analyses revealed that MyoD bound to eight of the sites. The expression of MyoD significantly enhanced Akt2 promoter activity and up-regulated Akt2 mRNA and protein levels. Moreover, Akt2 but not Akt1 was activated during differentiation. The expression of Akt2 activated MyoD-MEF2 transcriptional activity and induced myogenin expression. These data indicate that there is a positive feedback regulation loop between Akt2 and MyoD-MEF2 during muscle differentiation, which is essential for MyoD-induced myogenesis.

Base Sequence↗
PubMed2002

Crystal structures of the sugar complexes of Streptomyces olivaceoviridis E-86 xylanase: sugar binding structure of the family 13 carbohydrate binding module.

The family 10 xylanase from Streptomyces olivaceoviridis E-86 contains a (beta/alpha)(8)-barrel as a catalytic domain, a family 13 carbohydrate binding module (CBM) as a xylan binding domain (XBD) and a Gly/Pro-rich linker between them. The crystal structure of this enzyme showed that XBD has three similar subdomains, as indicated by the presence of a triple-repeated sequence, forming a galactose binding lectin fold similar to that found in the ricin toxin B-chain. Comparison with the structure of ricin/lactose complex suggests three potential sugar binding sites in XBD. In order to understand how XBD binds to the xylan chain, we analyzed the sugar-complex structure by the soaking experiment method using the xylooligosaccharides and other sugars. In the catalytic cleft, bound sugars were observed in the xylobiose and xylotriose complex structures. In the XBD, bound sugars were identified in subdomains alpha and gamma in all of the complexes with xylose, xylobiose, xylotriose, glucose, galactose and lactose. XBD binds xylose or xylooligosaccharides at the same sugar binding sites as in the case of the ricin/lactose complex but its binding manner for xylose and xylooligosaccharides is different from the galactose binding mode in ricin, even though XBD binds galactose in the same manner as in the ricin/galactose complex. These different binding modes are utilized efficiently and differently to bind the long substrate to xylanase and ricin-type lectin. XBD can bind any xylose in the xylan backbone, whereas ricin-type lectin recognizes the terminal galactose to sandwich the large sugar chain, even though the two domains have the same family 13 CBM structure. Family 13 CBM has rather loose and broad sugar specificities and is used by some kinds of proteins to bind their target sugars. In such enzyme, XBD binds xylan, and the catalytic domain may assume a flexible position with respect to the XBD/xylan complex, inasmuch as the linker region is unstructured.

Binding Sites↗
PubMed2002

Primary neck management among patients with cancer of the oral cavity without clinical nodal metastases: A decision and sensitivity analysis.

BACKGROUND: A standardized neck management strategy for oral cancer patients without clinical nodal metastases remains to be established. Consequently, a decision and sensitivity analysis of two neck management protocols, involving either prophylactic neck dissection or careful observation, was conducted using the Oral Cancer Registry of Kyushu, Japan. METHODS: We calculated probabilities of subclinical nodal metastases and 5-year survival using the registry data. A two-way sensitive analysis was conducted using the probabilities and parameters of the complete nodal metastasis resection rate (x) and a utility rating that describes the health state induced by dissection (y) compared with the neck condition in a careful-observation group. RESULTS: We solved the threshold curve for y and x for the expected utility between the two groups. The results showed that prophylactic neck dissection must guarantee a complete resection of subclinical nodal metastases with no disadvantage to health state to be evaluated as equally satisfactory as careful observation. CONCLUSIONS: Careful observation involving standardized systematic preoperative and postoperative screening of the neck seems preferable to prophylactic neck dissection for oral cancer patients without subclinical nodal metastases.

Carcinoma, Squamous Cell↗
PubMed2002

alpha-Galactosidase from cultured rice (Oryza sativa L. var. Nipponbare) cells.

The alpha-galactosidase from rice cell suspension cultures was purified to homogeneity by different techniques including affinity chromatography using N-epsilon-aminocaproyl-alpha-D-galactopyranosylamine as the ligand. From 11 l of culture filtrate, 28.7 mg of purified enzyme was obtained with an overall yield of 51.9%. The cDNA coding for the alpha-galactosidase was cloned and sequenced. The enzyme was found to contain 417 amino acid residues composed of a 55 amino acid signal sequence and 362 amino acid mature alpha-galactosidase; the molecular weight of the mature enzyme was thus calculated to be 39,950. Seven cysteine residues were also found but no putative N-glycosylation sites were present. The observed homology between the deduced amino acid sequences of the mature enzyme and alpha-galactosidases from coffee (Coffea arabica), guar (Cyamopsis tetragonolooba), and Mortierella vinacea alpha-galactosidase II were over 73, 72, and 45%, respectively. The enzyme displayed maximum activity at 45 degrees C when p-nitrophenyl-alpha-D-galactopyranoside was used as substrate. The rice alpha-galactosidase and Mortierella vinacea alpha-galactosidase II acted on both the terminal alpha-galactosyl residue and the side-chain alpha-galactosyl residue of the galactomanno-oligosaccharides.

Amino Acid Sequence↗
PubMed2002

Trend of brain tumor incidence by histological subtypes in Japan: estimation from the Brain Tumor Registry of Japan, 1973-1993.

In order to estimate the risk of primary brain tumor (PBT), we attempted to estimate the national incidence rates of PBT by histological subtypes using the Brain Tumor Registry of Japan (BTR). The number of deaths due to PBT in a certain year is the sum of the deaths among patients diagnosed in different years. Registered cases in the BTR represent incident cases of PBT in the whole country multiplied by a cover rate. The cover rate is defined as the proportions of PBT cases that the Registry counts in relation to all the cases in the country in a given year. If the survival experience among the registered cases represents the survival experience of all cases, then the rate of registered deaths represents all deaths due to PBT in Japan. By this logic, we estimated the cover rates and incidence rates from 1973 to 1993 using the BTR and National Vital Statistics data. Our estimates showed three patterns of time trends: (1) a gradual linear increasing trend before the 1980s followed by a plateau (total PBT, gliomas, meningioma, and hemangioblastoma), (2) a trend with a step-up increase in the 1980s followed by a plateau (germ cell tumor and pituitary tumor), and (3) a linear increasing trend throughout the observation period with no plateau (malignant lymphoma and neurinoma). Furthermore, obvious sex differences in time trends were observed in rates of meningioma, germ cell tumor, and pituitary tumor. The results of this study demonstrated several distinctive patterns in time trends, which give us insight into the possible etiologies of brain tumors. Further epidemiological study is needed to elucidate these findings.

Age Factors↗
PubMedDate not supplied

5-year survival rates for primary cancer sites at cancer-treatment-oriented hospitals in Japan.

In Japan, The Japanese Association of Clinical Cancer Centers (JACCCs) was established in 1965 by systematizing cancer-treatment-oriented hospitals. The core center of JACCCs is the National Cancer Center in Tokyo. In 1984, JACCCs created The "Improvement for Clinical Cancer Centers in Japan" Study Group (The Study Group) which has subsequently routinely evaluated the effectiveness of the therapy that is provided. In general, the 5-year (relative) survival rate is employed as an indicator of the treatment efficacy. The present survey used the PC software program KAP developed by Chiba Cancer Center in Japan, to calculate 5-year observed survival rates and the 5-year relative survival rates using Ederer II methods. The overall 5-year relative survival rates in patients with stomach (15,353 patients), colon (5,054), rectum (3,695), lung (10,153), breast (11,302) and cervix of the uterus (6,336) were 68.7%, 72.2%, 69.4%, 28.1%, 86.1% and 81.1%, respectively. The survival rates discussed so far are principally observed survival rates. The 5-year relative survival rate for those institutions that specialize in cancer treatment should become an index for Japanese cancer treatment.

Breast Neoplasms↗