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Biomedical subjects

T Sudo

Publications and source records attributed to T Sudo.

At least 235 records · Page 13Linked to original sources
PubMed1983

Study of passed stones by means of X-rays, infrared and thermal analyses.

X-ray powder diffraction, infrared spectroscopy and thermal analysis were used to study 108 stones that had been passed spontaneously from the upper urinary tract. The presence of apatite in pure calcium oxalate stones classified by x-ray diffraction was confirmed by infrared analysis of the ignited product. Consequently, 102 of 108 stones were found to be composed of weddellite and/or whewellite, and apatite. Besides the contents of weddellite, whewellite and apatite, the content of organic matrix also was estimated by thermal analysis in 102 stones, ranging from 1.1 to 17.2 per cent. The stones then were divided into 3 groups according to the principal constituent: 1) weddellite, 2) whewellite and 3) apatite. Weddellite stones were significantly heavier and significantly higher in apatite content than whewellite stones. It is suggested that weddellite calculi tend to become larger than whewellite stones. The apatite content was correlated with the ratio of weddellite to weddellite plus whewellite ( r equals 0.528), and the content of organic matrix was correlated with the whewellite content (r equals 0.708). Thus, it is considered that the weddellite-apatite and whewellite-organic matrix associations have important roles in the development and growth of weddellite and whewellite calculi, respectively.

Apatites↗
PubMed1983

Translation of human interleukin 2 mRNA in Xenopus laevis oocytes.

Poly(A)-positive mRNA extracted from tonsillar mononuclear cells stimulated with phytohemagglutinin-M and 12-o-tetradecanoyl phorbol 13-acetate was successfully translated into biologically active interleukin 2 (IL-2) in Xenopus laevis oocytes, and secreted into the incubation medium. In control experiments, the extract of oocytes injected with either poly(A)-negative RNA or buffer did not show any IL-2 activity. By sucrose density gradient centrifugation analysis, IL-2 mRNA was found as a single peak corresponding to a sedimentation coefficient of 10-11S.

Animals↗
PubMed1983

Lipid droplets containing DNA-histones released in the culture medium of transformed rat fibroblasts (HY1).

Lipid droplets appeared during the growing phase in the culture medium of incompletely transformed rat fibroblasts (HY1) induced by AccI-H fragments of adenovirus 12 DNA. These droplets consisted of neutral lipids, DNA, histones and RNA. Electron microscopic observations showed that the droplets had no lipid-bilayers on their surfaces which accounted for the tendency of the droplets to readily fuse together and become larger, and that the inner structures of the droplets looked like networks of fibrous matter. Experiments with DNA hybridization showed that the droplet DNA was composed of both cellular and adenoviral DNA, and that the cellular DNA in the droplets seemed to be derived from various cell DNA sequences. These results suggest that the droplets were derived from parts of the nuclear components of HY1 cells. The mechanisms for droplet release are discussed.

Adenoviridae↗
PubMed1983

Expression of heterophil Forssman antigen on cultured malignant cell lines.

By means of indirect immunofluorescence (IIF) tests with rabbit antiserum against Forssman (F) antigen, F-antigen was demonstrated on 5 of 7 cultured cell lines originating from various cancer tissues. Results of cytotoxicity tests with normal human sera with F-antibodies confirmed the presence of F-antigen on these "IIF-positive" cell lines. In contrast, F-antigen could not be detected under the same experimental conditions on B-cell lines established from lymphoma or leukemia patients or on lymphoblastoid cell lines established from normal individuals. The expression of F-antigen was also studied on transformed rat cell lines derived from an F-negative normal cell line, 3y1. Transformation of the 3y1 line by whole DNA or by the EcoRI-C fragment (0-16 map unit) but not by the Accl-H fragment (0-4.7 map unit) of adenovirus type 12 resulted in expression of F-antigen on the cell surface. The transformed cells with F-antigen showed an in vitro growth pattern characteristic of that seen in malignant cells; this observation indicates that F-antigen expression is closely associated with malignant transformation of the cells.

Adenoviridae↗
PubMed1983

Multidrug-resistance phenotype in Chinese hamster ovary cells.

Multidrug resistance is a complex pleiotropic phenotype of cross-resistance and collateral sensitivity to unrelated compounds observed in many mammalian cell mutants selected for resistance to single agents. In Chinese hamster ovary cells, colchicine-resistant mutants expressing this phenotype have been characterized extensively. Such mutants arise apparently from a single genetic event, and the basis of this phenotype appears to be localized at the membrane level, resulting in altered drug permeability. Expression of a 170,000-dalton surface glycoprotein (P-glycoprotein) has been identified to correlate with the multidrug-resistance phenotype. Selection of a second mutation in colchicine-resistant mutants, for resistance to phytohemagglutinin, results in an alteration of the carbohydrate moiety in P-glycoprotein and other surface components. This mutation does not noticeably affect the multi-drug-resistance phenotype. The altered permeability of mutant cells to drugs, however, can be modulated by nonionic detergents or metabolic inhibitors. These findings are consistent with a molecular mechanism of multidrug resistance whereby the pleiotropic response of the cell is mediated by an overexpression of a cell-surface protein, the P-glycoprotein.

Animals↗
PubMed1982

Pancreatic endocrine function after total gastrectomy and truncal vagotomy.

Oral and intravenous glucose tolerance tests were performed in four groups: (1) preoperative patients, (2) patients with interposition reconstruction after total gastrectomy, (3) patients with Roux-Y reconstruction after total gastrectomy, and (4) patients with intrathoracic replacement after esophagectomy. We obtained the following results: (1) Hyperglucagonemia in response to orally administered glucose occurred after truncal vagotomy and occurred in the presence and absence of gastric tissue. (2) compared wtih the preoperative study, all postoperative groups demonstrated glucose intolerance. (3) The glucose intolerance was due to increased glucagon, insulinopenia, and possibly nutritional factors. (4) The insulin response to intravenous glucose suggests an impairment in the first phase of insulin secretion in the surgically treated group, demonstrating a role for the vagus in insulin secretion. (5) The glucose tolerance curve shows that the interposition operation is superior the the Roux-Y operation.

Adult↗
PubMed1982

In vitro replication of recombinant plasmids carrying chromosomal segments of Xenopus laevis.

Recombinant plasmids carrying a segment of Xenopus laevis chromosomal DNA were constructed with plasmid pBR322 as the vector. A recombinant plasmid pXY65 carrying a 3.2-kilobase BamHI segment of the chromosome of X. laevis has been found to contain a repetitive sequence dispersed throughout the X. laevis chromosomes. This plasmid initiated replication in vitro when the supercoiled circular molecules were incubated in a replication system. The other recombinant plasmids tested and the pBR322 vector were not replicated. Electron microscopic analysis of the replicative intermediates showed that the replication was initiated at a specific site in the 3.2-kilobase BamHI segment of pXY65 and that the replication usually proceeded bidirectionally. Analysis of the reaction products by centrifugation in alkaline sucrose gradients indicated that short pieces were synthesized in the in vitro replication system. DNA synthesis was inhibited in vitro by the addition of aphidicolin and by omission of dNTPs. These results indicate that the X. laevis segment cloned in pXY65 contains a site capable of initiating replication in vitro.

Animals↗
PubMed1981

Microheterogeneity among carbohydrate structures at the cell surface may be important in recognition phenomena.

Independently derived mutants of Chinese hamster ovary cells have been isolated and shown to exhibit a subtle glycosylation defect resulting in the premature termination of certain asparagine-linked carbohydrate moieties. This carbohydrate alteration is akin to the types of structural variation termed microheterogeneity and is thought not to affect the biological activities of glycoproteins that manifest the phenomenon. However, the carbohydrate change expressed by the mutants is stable and heritable, and 125I-lectin-binding studies suggest that it profoundly alters their surface recognition properties. The mutation appears to affect a specific subpopulation of galactose residues in asparagine-linked carbohydrate of the type found associated with the G glycoprotein of vesicular stomatitis virus. The mutant cells also exhibit morphological changes in substratum culture.

Animals↗
PubMed1981

Effect of CaCl2 on production of interferon and synthesis of its mRNA in human MG-63 cells.

The effect of excess CaCl2 addition on the production of interferon and synthesis of its mRNA in a human cell line was investigated. Human MG-63 cells which were treated with 7 mM CaCl2 after poly(rI).poly(rC) induction produced 3 to 10 times as much interferon as control cells. Increased interferon mRNA activity was obtained from CaCl2 treated cells, suggesting that there was an increased interferon mRNA production in these cells.

Animals↗