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Biomedical subjects

S Ogata

Publications and source records attributed to S Ogata.

At least 127 records · Page 7Linked to original sources
PubMed1995

Clinical abnormalities in adults with pancreaticobiliary maljunction with and without bile-duct dilatation.

OBJECTIVE: To study clinical diseases associated with pancreaticobiliary maljunction with or without bile-duct dilatation. DESIGN: A retrospective study over 16 years. SETTING: A single university surgical service in Japan. PATIENTS: Thirty-three patients with pancreaticobiliary maljunction. MAIN OUTCOME MEASURES: Gallstones and cancer in patients with and without bile-duct dilatation. RESULTS: Twenty-five patients had dilatation of the bile duct, 8 did not. Seven (28%) of the 25 patients with bile-duct dilatation had gallstones compared with 1 (12%) of the 8 patients with no dilatation. Seven (88%) of the 8 patients with no dilatation had carcinoma (all of the gallbladder), but only 3 (12%) of the 25 patients with bile-duct dilatation had carcinoma (1 of the gallbladder, 2 of the bile duct). CONCLUSION: Prophylactic cholecystectomy is recommended for patients with pancreaticobiliary maljunction and no dilatation of the bile duct because of the high incidence of gallbladder cancer.

Adolescent↗
PubMed1995

Adherence of Helicobacter pylori to cultured human gastric carcinoma cells.

AIM: To examine the binding activity of Helicobacter pylori to cultured gastric epithelial cells using flow cytometry. MATERIALS AND METHODS: We evaluated the adherence of 15 H. pylori strains to cultured gastric cancer (MKN45) cells by flow cytometric analysis. Other bacterial strains were also analysed for their adherence to MKN45 cells. In addition, we examined the effect of fetuin on the adherence of H. pylori to MKN45 cells. RESULTS: H. pylori strains adhered to MKN45 cells at rates of between 49 and 93.7%, with a mean of 75.3%. In contrast, the rates of Escherichia coli, Shigella flexneri, Vibrio cholerae and Yersinia enterocolitica adherence to MKN45 cells were 69.1, 5.9, 11.7 and 33.1%, respectively. Fetuin had no inhibitory effect on the adherence of H. pylori to MKN45 cells in the flow cytometric analysis. CONCLUSIONS: A flow cytometric analysis using MKN45 cells proved to be an objective and sensitive method for evaluating the adherence of H. pylori, showing close adherence between this organism and gastric epithelial cells.

Bacterial Adhesion↗
PubMed1995

Computer graphics of center of masticatory forces in complete dentures.

1. INTRODUCTION. In dental education, it is valuable to show visually the differences between a good-fitting and an ill-fitting complete denture. A vector of masticatory forces across all the teeth of the denture is available to estimate the capability of the denture. The vector is simple while the forces exerted on a denture are very complex. A vector has only two factors, the point of application (center of force) and the magnitude. Because a complete denture acts as a unit, we can obtain the vector from electrical signals detected by transducers installed in the denture base. The aim of this study was to develop software which is able to show visually to dental students, the differences between the vectors of the dentures of three representative complete denture wearers. 2. METHODS. Three subjects, each with either a good, a moderate or an ill-fitting complete denture, were selected. Subject 1 could use the denture very comfortably during experiment. Subject 2 was uncomfortable at the insertion of the new denture, but after adaptations to the denture he could use it very well. Subject 3 had been uncomfortable during the experiment. A bottom complete denture was divided into upper and lower parts. These were connected by the four force-detecting units which were embedded in approximately the first premolar and second molar regions on both sides of the denture. The electric signals from these units during the chewing of peanuts and raisins (sampling time period: 30 msec) were recorded as digital signals and processed using the computer (Macintosh IIcx, Apple Computer) with the A/D converter (Lab-NB), National Instruments). Center and magnitudes of masticatory force were calculated from all sampling points using our newly developed software scripted by ¿C¿ (MPW C, Apple Computer). On the other hand, a tracing of the external shape of the dentition of the denture was made using the project (V-12, NIKON). The tracing of the dentition, with center and magnitude of masticatory forces was displayed successively on the screen like a movie. 3. RESULTS AND DISCUSSION. The typical scenes in each cases during one stroke of chewing were illustrated in Figure 1. The center of each circle is the point of application of the vector and the diameter of the circle is its magnitude. As time proceeded, the diameter of the circle became larger. As the period of denture insertion proceeded, the center of masticatory force was localized on the first molar region in subject 1, was shifted from the middle of the dental arch to the molar in subject 2, and was irregularly moved on the middle of the dental arch in subject 3. This software could visualize the center of masticatory force as an indicator of the type of fitting of the complete denture on display.

Bite Force↗
PubMed1994

Structure of the glycosylphosphatidylinositol membrane anchor of human placental alkaline phosphatase.

The glycosylphosphatidylinositol membrane anchor of human placental alkaline phosphatase was isolated by exhaustive proteolysis followed by hydrophobic interaction chromatography. The resulting glycosylphosphatidylinositol-peptide was subjected to compositional analysis and chemical and enzymic modifications. The neutral-glycan fraction, prepared by dephosphorylation followed by HNO2 deamination and reduction, was sequenced using exoglycosidases and acetolysis. The phosphatidylinositol moiety was analysed by fast-atom bombardment mass spectrometry and gas chromatography-mass spectrometry. Taken together the data suggest the structure, Thr-Asp-ethanolamine-PO4-Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcN-(sn-1-O- alkyl-2-O-acylglycerol-3-PO4-1-myo-D-inositol), which contains an additional ethanolamine phosphate group at an unknown position.

Alkaline Phosphatase↗
PubMed1994

Lysosomal targeting of Limp II membrane glycoprotein requires a novel Leu-Ile motif at a particular position in its cytoplasmic tail.

A class of integral membrane glycoproteins specific to lysosomes has been identified, and they are classified into two separate groups depending on whether or not their cytoplasmic sequence contains a tyrosine residue. Lamp-1 and lamp-2 have a tyrosine-containing motif in their cytoplasmic segments, and this motif was found to direct the glycoproteins to lysosomes. Limp II glycoprotein, on the other hand, lacks a tyrosine in its cytoplasmic segment and it must be directed to lysosomes by a different signal (Fukuda, M. (1991) J. Biol. Chem. 266, 21327-21330). In order to elucidate the targeting signal of Limp II, a cDNA encoding its cytoplasmic segment was fused with a reporter molecule, a chimeric protein of human gonadotropin alpha chain-vesicular stomatitis G-protein transmembrane. After various mutations its expression was examined by immunofluorescence. First it was shown that a chimeric protein with a Limp II wild-type tail is transported to lysosomes. Deletion of the three amino acids of the cytoplasmic tail at the carboxyl terminus abolished this sorting to lysosomes. Substitution of individual amino acids revealed that the Leu-Ile motif in the Leu-Ile-Arg-Thr sequence at the carboxyl terminus is crucial to the sorting signal. When this motif was brought closer to the transmembrane domain by deletion of nine amino acids next to the transmembrane domain, this sorting function was abolished. In addition, substitution of alanine for the serine, which is at 5 residues from the transmembrane also abolished the sorting capacity, although there was no evidence that the phosphorylation of serine is involved in sorting. Altered proteins that were not transported to lysosomes were found to accumulate at the cell surface and, unlike proteins with a wild-type cytoplasmic tail, were unable to undergo endocytosis. These results indicate that the carboxyl-terminal amino acid sequence, including the Leu-Ile motif and the sequence that connects the motif to the transmembrane domain, is critical for the sorting of Limp II to lysosomes.

Amino Acid Sequence↗
PubMed1994

Isolation of thermosensitive mutants of Yersinia enterocolitica by transposon insertion.

During bacterial infection, pathogens are exposed to a variety of stimuli, e.g., sudden temperature increase on entering mammalian host or oxidative stress associated with exposure to phagocytes. Yersinia enterocolitica, which is a facultative intracellular bacteria, responds to macrophage phagocytosis by the production of a set of stress proteins; which are also induced by heat shock (Yamamoto et al., 1994, Microbiol. Immunol. 38, 295-300). To examine the role of bacterial stress proteins in the adaptation to environmental changes encountered during infectious processes, we have isolated stress-sensitive mutants from Y. enterocolitica in which mini-Tn10 transposon insertions allow bacterial growth at 28 degrees C but prevent growth at an elevated temperature, 39 degrees C. Eight independent insertions were obtained and preliminarily characterized by Southern blot hybridization and morphological analysis.

Bacterial Proteins↗
PubMed1994

Impalement injury of the thorax: report of a case.

We report herein the case of a 33-year-old man who survived an impalement injury of the thorax involving the heart, esophagus, and spinal cord. The patient was transported to our hospital with the impalement object left in situ and it was extracted under cardiopulmonary bypass in an operating room. The important principles of surgical management contributing to the successful outcome of such patients are discussed following the presentation of this case.

Adult↗
PubMed1994

Extended central bisegmentectomy--an en bloc resection of hepatic segments 4, 5, 8 and 7: report of a case.

We herein present an example of an extended central bisegmentectomy in a patient with a large hepatocellular carcinoma. According to a magnetic resonance imaging study, the right hepatic vein was displaced and narrowed at its origin and a large inferior right hepatic vein was revealed. In this case, owing to the only slightly functional remaining hepatic reserve, an extended central bisegmentectomy was selected as the optimum treatment. The postoperative course was uneventful except for some bile leakage. Twelve months after operation, the patient is still alive and no sign of recurrence has been detected. The extended central bisegmentectomy is an en bloc resection of hepatic segments 4, 5, 7, and 8. When the large inferior right hepatic vein is present, segment 6 can be preserved even when the right hepatic vein is sacrificed at its origin.

Carcinoma, Hepatocellular↗
PubMed1994

Induction of Yersinia enterocolitica stress proteins by phagocytosis with macrophage.

Yersinia enterocolitica is a facultative intracellular pathogen which invades to epithelial cells and survives in phagocytes. Since the internal environment of phagocytes should be stressful conditions for the phagocytosed Yersinia, the bacteria should respond to protect themselves from otherwise lethal results. We analyzed the stress-induced proteins which possibly contribute to survival of Yersinia within the phagocytes. Y. enterocolitica was radiolabeled during the growth in macrophage-like J774-1 cells, and the bacterial proteins were analyzed by two-dimensional gel electrophoresis. At least 16 proteins were selectively induced in response to phagocytosis, and several out of 16 proteins were also induced by heat shock at 42 C or oxidative stresses in vitro. Of those, two major stress proteins were identified to be homologues of DnaK and CRPA by immunoblotting analysis. These results have indicated that Y. enterocolitica exhibits a global stress response to the hostile environment in the phagocytosed macrophage.

Animals↗
PubMed1994

Detection and characterization of antibodies to bacterial heat-shock protein 60 in sera of patients with primary biliary cirrhosis.

The enzyme-linked immunosorbent assay (ELISA) with bacterial heat-shock protein 60 (HSP60) purified from Yersinia enterocolitica (Ye) revealed that the antibodies directed against YeHSP60 existed in sera of patients with primary biliary cirrhosis (PBC). To characterize the epitope specificity of the antibodies in patients, the epitope mapping of HSP60 by means of the antibodies was performed. The results have suggested that the epitope recognized with anti-HSP60 antibodies in PBC relates to the amino acid sequence of YeHSP60 molecule as follows: DLGQAKRVVINKDTTIIIDGVGDEAAIQGRLAQIRQQIEEATSDYDKEK.

Amino Acid Sequence↗
PubMed1993

Cytochrome P-450 in liver microsomes of streptozotocin-induced diabetic rats: purification and characterization.

Two diabetes-inducible forms of cytochrome P-450, named P-450ST-1 and -ST-2, were purified from the liver microsomes of streptozotocin-diabetic male rats by sodium cholate solubilization, octylamino-Sepharose 4B chromatography and high-performance liquid chromatography with DEAE-5PW and hydroxyapatite columns. The purified P-450 forms gave a single band each on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with an apparent molecular weight of 48,500 for P-450ST-1 or 48,000 for P-450ST-2. The CO-reduced spectral maxima of P-450ST-1 and -ST-2 were at 451 nm. The two cytochromes had the low-spin state of heme in the oxidized form. Both P-450ST-1 and -ST-2 catalyzed the metabolism of aniline, benzphetamine, p-nitroanisole, testosterone and aminopyrine. However, the catalytic activity of P-450ST-2 for these substrates was apparently higher than that of ST-1. Analyses of the NH2-terminal amino-acid sequence and Western immunoblot showed that P-450ST-1 and -ST-2 differed structurally from each other. The catalytic activities, molecular weights, NH2-terminal sequences and/or immunochemical properties of P-450ST-1 and -ST-2 did not agree with those of the other cytochrome P-450 forms purified from diabetic rats previously.

Amino Acid Sequence↗
PubMed1993

A novel human macrophage-derived intestinal mucin secretagogue: implications for the pathogenesis of inflammatory bowel disease.

BACKGROUND: A novel 68-kilodalton macrophage-derived protein (MMS-68) stimulating mucin release from respiratory epithelial cells has previously been described. In this study, the effect of MMS-68 on mucin release from intestinal epithelial cells was determined. METHODS: Colonic epithelial cells isolated from normal colon, ulcerative colitis, Crohn's colitis, and cells from three colon cancer cell lines were labeled with [3H]-glucosamine and stimulated with MMS-68. High molecular weight glycoproteins were precipitated and counted. RESULTS: In all of the cells tested, MMS-68 enhanced mucin secretion by 1.46-2.0-fold above control values, comparable to the level achieved with carbachol (10(-5) mol/L). Coincubation with anti-MMS-68 monoclonal antibody 1D-10 blocked this bioactivity. Freshly isolated intestinal macrophages reacted with monoclonal antibody 1D-10. Immunofluorescent staining of frozen sections revealed the presence of MMS-68-producing cells (macrophages) in the lamina propria of normal colon and Crohn's colitis, with weaker expression in ulcerative colitis mucosa. CONCLUSIONS: Intestinal macrophages produce a novel mucin secretagogue, which is as potent as carbachol for stimulating mucin secretion from colonic epithelial cells. This factor may explain, in part, the alterations in mucin secretion often seen in inflammatory bowel disease.

Antibodies, Monoclonal↗