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C Hashimoto

Publications and source records attributed to C Hashimoto.

At least 73 records · Page 4Linked to original sources
PubMed1982

Structure and function of small ribonucleoproteins from eukaryotic cells.

Autoantibodies from patients with systemic lupus erythematosus and other related diseases have been used to identify and study small RNA-protein complexes from mammalian cells. Properties of three previously described and several new classes of small ribonucleoproteins (RNPs) are reviewed. The sequence of Drosophila U1 RNA reveals that the region proposed to pair with 5' splice junctions is conserved, while that proposed to interact with 3' junctions diverges; this forces some revision of the model for U1 small nuclear (sn)RNP participation in hnRNA splicing. Further characterization of the Ro and La small RNPs has shown that the Ro small cytoplasmic (sc)RNPs are a subclass of La RNPs. Both tRNA and 5S rRNA precursors are at least transiently associated with the La protein. This raises the possibility that the La protein may be an RNA polymerase III transcription factor.

Antigen-Antibody Complex↗
PubMed1981

Carbohydrate chains on yeast carboxypeptidase Y are phosphorylated.

Carboxypeptidase Y, a vacuolar enzyme from Saccharomyces cerevisiae, was digested with endo-beta-N-acetyl-D-glucosaminidase H to release the four oligosaccharide chains that are linked to asparagine in the glycoprotein. The oligosaccharides were fractionated into a neutral and acidic component, and the latter proved to phosphorylated. From its gel filtration pattern, the neutral fraction was shown to be a mixture of at least four homologs, the smallest of which had a proton NMR spectrum almost identical to that given by an IgM oligosaccharide with eight mannoses and one N-acetylglucosamine [Cohen, R. E. & Ballou, C. E. (1980) Biochemistry 19, 4345--4358]. The yeast oligosaccharide has one additional mannose unit in an alpha 1 leads to 3 or alpha 1 leads to 6 linkage, whereas the larger homologs appear to have two, three, and four more mannose units. One phosphorylated oligosaccharides with a mannose/phosphate ratio of 12.5 was reduced with NaB3H4 and then subjected to mild acid hydrolysis. This released mannose and mannobiose that were glycosidically linked to the phosphate group, whereas complete acid hydrolysis yielded D-mannose 6-phosphate. The recovered oligosaccharide phosphomonoester, which contained 11 or 12 mannose units, was digested exhaustively with alpha-mannosidase, and the product of this reaction was treated with alkaline phosphatase, which yielded radioactive Man3GlcNAcH2. These results suggest that the mannosidase-resistant phosphorylated oligosaccharide has the structure Man leads to P leads to 6 alpha Man leads to alpha Man leads to 6 beta Man leads to 4GlcNAcH2, in which some of the phosphate groups are substituted with mannobiose instead of mannose. A second phosphorylated oligosaccharide with a mannose/phosphate ratio of 6.5 probably contains two phosphodiester groups, but its structure has not been investigated in detail.

Carboxypeptidases↗
PubMed1980

Characterization of phosphorylated oligomannosides from Hansenula wingei mannoprotein.

Yeast cell wall mannoproteins often contain phosphate esterified to the oligosaccharide side chains, and partial acetolysis yields both neutral and phosphorylated fragments [Thieme, T. R., & Ballou, C. E. (1971) Biochemistry 10, 4121--4129]. We have isolated the acidic acetolysis fragments from Hansenula wingei mannoprotein [Yen, P. H., & Ballou, C. E. (1974) Biochemistry 13, 2420--2427] and have separated them into a mannopentaose monophosphate (Man5P) and a mannotriose monophosphate (Man3P). On the basis of selective enzymatic and partial acid hydrolysis and 1H and 31P NMR studies, Man5P was shown to have the structure P leads to 6 alpha Man1 leads to 3 alpha Man1 leads to 2 alpha Man1 leads to 2 alpha Man1 leads to 2Man (where Man = D-mannopyranose). The 31P NMR spectrum of the Man3P showed it to be a mixture of a phosphate monoester and a phosphate diester, which was separated by ion-exchange chromatography. The monoester had the structure P leads to 6 alpha Man1 leads to 3 alpha Man1 leads to 3Man whereas the diester had the properties of a cyclic phosphate. Although native H. wingei mannoprotein contains phosphodiester linkages, the starting mannoprotein preparation was isolated under alkaline conditions that hydrolyze such bonds, and it did not show a phosphodiester signal in the 31P NMR spectrum. We conclude that the cyclic phosphate was an artifact formed during the acetolysis reaction. Because acetolysis of H. wingei mannoprotein yields only phosphorylated mannotriose and mannopentaose whereas the mannoprotein contains mannotetraose side chains as well, the phosphorylation process must be a very specific event in the biosynthesis of the glycoprotein.

Ascomycota↗
PubMed1979

Circular dichroism spectra of purified cytochromes P-450 from rabbit liver microsomes.

Circular dichroism (CD) spectra were measured for cytochromes P-450 (P-450) purified from phenobarbital- and 3-methylcholanthrene-induced rabbit liver microsomes. No striking difference in alpha-helix content was seen between phenobarbital-induced P-450 (PB P-450) (50%), phenobarbital-induced P-448 (PB P-448) (40%) and 3-methylcholanthrene-induced P-448 (MC P-448) (45--50%) in terms of ultraviolet CD spectra. Strong negative CD spectra associated with 3-methylcholanthrene transitions for MC P-448 in the near-ultraviolet region (250--310 nm) and weaker negative CD spectra associated with Soret transitions for PBP-448 ([theta] = 50 000) and MCP-448 ([theta] = 160 000), indicated that structures of these preparations are strikingly different from each other. Reduction of P-450 and P-448 led to a remarkable decrease of the Soret CD trough, suggesting that reduction was accompanied by a striking conformational change in the vicinity of the heme. Since CO complexes of reduced P-450 and P-448 showed a CD trough and an S-shaped CD, respectively, associated with the absorption peak at 450 nm, the heme vicinities are remarkably different from each other. The CD spectra in the visible region are also discussed. It was noticed that P-420, the denatured form of P-450, exhibited no CD spectra in the Soret and visible regions.

Animals↗
PubMed1978

Use of the stomach as an esophageal substitute.

Esophagoplasty with isoperistaltic stomach is a useful and satisfactory means of reconstruction of the esophagus. It is simpler and there is no necessity for using a reversed gastric tube. The most essential points of technique for the modelling of the stomach, is taking advantage of the ample intramural vascular network and adequate selection of the highest point of the stomach for the site of the esophago-or pharyngogastrostomy. To utilize the intramural vascular network, sufficient width of the stomach is necessary. This also allows stretching of the stomach. Esophageal resection and reconstruction using the isoperistaltic stomach above the level of the neck was performed on 130 cases. Among them 40 cases were pharyngogastromies and 90 cases were cervical esophagogastromies. There was one operative death due to alcoholic liver cirrhosis (operative mortality rate 0.8%). If the stomach is properly handled, esophageal replacement by the isoperistaltic stomach gives constant success.

Esophageal Diseases↗
PubMed1976

Resection and reconstruction for carcinoma of the thoracic oesophagus.

The technique and results of oesophageal resection through a right thoracotomy and laparotomy with reconstruction utilizing the stomach via a retrosternal route are reported. Forty patients underwent this procedure, with no mortality. The average blood loss during operation was 424 ml, and 72% of this series underwent the operation without blood transfusion. It is believed that this type of one-stage operation for carcinoma of the oesophagus is reasonable from the viewpoint of adequate resection of malignancies, and it can be performed with minimal surgical risk. With experience, perhaps it will become a standard method such as the Billroth I method in gastric surgery.

Esophageal Neoplasms↗
PubMed1976

The inactivator of the first component of human complement (C1INA): the complex formation with plasmin.

The reaction of C1INA with plasmin was followed by the stoichiometric inactivation of both activities. On acrylamide gel electrophoresis, the reaction mixture revealed 3 new substances. One formed a precipitin band against anti-C1INA and its molecular weight was 103,000 daltons, 14,000 less than that of C1INA, indicating that a portion of C1INA was partially cleaved by the proteolytic activity of plasmin. Each of the other two substances formed precipitin bands against anti-C1INA as well as against anti-plasminogen. Molecular weights of these two substances were 200,000 and 179,000 daltons, whereas the molecular weights of C1INA and plasmin are 117,000 and 82,000 daltons, respectively. From these results, it was concluded that a portion of C1INA in the reaction mixture was partially cleaved by plasmin, and the partially cleaved C1INA as well as the native C1INA form 1:1 molecular complexes with plasmin, leading to inactivation of these activities.

Animals↗