Biomedical subjects

S Ogata

Publications and source records attributed to S Ogata.

At least 73 records · Page 4Linked to original sources

PubMed1998

Enzymatic basis for sialyl-Tn expression in human colon cancer cells.

Sialyl-Tn antigen (SAalpha2-6 GalNAc alpha-Ser/Thr) is expressed as a cancer-associated antigen on the surface of cancer cells and its expression correlates with a poor prognosis in patients with colorectal and other adenocarcinomas. To understand the enzymatic basis of sialyl-Tn (STn) antigen expression, we used two clonal cell lines, LSB and LSC, derived from LS174T human colonic cancer cells. LSC cells express only the truncated carbohydrate antigen Tn (GalNAc alpha-Ser/Thr) and sialyl-Tn on their mucin molecules, whereas LSB cells express elongated oligosaccharide chains. Both cell lines demonstrated similar activities of glycosyltransferases involved in the biosynthesis of elongated and terminal structures of complex O-glycans. However, LSC cells were unable to synthesize core 1 (Gal beta1-3GalNAc-) because the ubiquitous enzyme activity of UDP-Gal:GalNAc-R beta3-Gal-transferase (core 1 beta3-Gal-transferase) was lacking. Core 1 beta3-Gal-transferase could not be reactivated in LSC cells by treatment with sodium butyrate or by in vivo growth of LSC cells in nude mice. In contrast, LSB cells were able to synthesize and process core 1 and core 2 (GlcNAc beta1-6 (Gal beta1-3) GalNAc-). LSC cells represent the first example of a non-hematopoietic cell line which lacks core 1 beta3-Gal-transferase activity. The lack of core 1 beta3-Gal-transferase in LSC cells explains why they are incapable of forming the common mucin O-glycan core structures and are committed to synthesizing the short Tn and STn oligosaccharides. These findings suggest that the activity of core 1 beta3-Gal-transferase is an important determinant of the STn phenotype of colon cancer cells.

Amino Acid Sequence↗

PubMed1998

Histologic findings in polyacrylamide-coated polytetrafluoroethylene (PTFE) arterial grafts in the rat abdominal aorta.

To improve cell attachment without inducing thrombogenesis, the authors coated the inner surface of polytetrafluoroethylene (PTFE) prostheses (I.D.: 1 mm; length: 10 mm; wall thickness: 0.5 mm; fibril length: 30 microm) with polyacrylamide (PAA), known to have a strong antithrombotic effect (PAA-PTFE). They implanted the prostheses into the abdominal aorta of rats, and retrieved them at intervals of up to 9 months. Graft healing was observed under light and scanning electron microscopy. All the inner surfaces of the grafts examined were barely covered with fibrin or platelets. The PAA-coated fibers had many projections, in contrast to the original PTFE prostheses. Neo-endothelium was observed to be directly attached to these structural fibers of the PAA-PTFE grafts. Restoration of the neointima was also observed in these vascular prostheses.

Acrylic Resins↗

PubMed1998

Mucin secretion in inflammatory bowel disease: comparison of a macrophage-derived mucin secretagogue (MMS-68) to conventional secretagogues.

We have described a novel macrophage-derived mucin secretagogue (MMS-68) that mediates mucin secretion in colon cancer cell lines and explants of normal and inflammatory bowel disease (IBD) mucosa. We compared MMS-68 induced mucin release with other known intestinal mucin secretagogues in normal colon explants and in the HT-29 colon cancer cell line, and to study the effects of MMS-68 on mucin release from inflamed and uninflamed ulcerative colitis (UC) and Crohn's disease (CD) mucosa. In normal colonic explants and HT-29 cells, each of the secretagogues including, MMS-68-induced mucin release two- to fivefold more than culture medium alone. In HT-29 cells, MMS-68 plus leukotriene C4 (LTC4) induced a 50% increase in mucin release over either secretagogue alone, and MMS-68 plus platelet-activating factor (PAF) markedly enhanced mucin release by eightfold over either secretagogue. In colonic explants from patients with UC and CD, the mucin release in response to MMS-68 was similar to that of normal colonic explants. Likewise, in isolated epithelial cells from CD and UC (whether involved or uninvolved), MMS-68-induced release was similar to that of epithelial cells isolated from normal colonic mucosa. The number of MMS-68-producing macrophages was lower in uninflamed UC mucosa compared with inflamed UC mucosa and CD mucosa. The mucin secretagogue activity of MMS-68 is comparable to that of other known secretagogues, and PAF can have a synergistic effect on this activity. Whole tissue explants and isolated colonic epithelial cells from patients with IBD respond at least as well as their normal counterparts to MMS-68. MMS-68 may play a role in mucin secretion in normal and inflamed colonic tissue.

Carbachol↗

PubMed1998

Cerebral blood volume in the sleep measured by near-infrared spectroscopy.

We investigated the relationship between hemodynamic changes in the cortex measured by near-infrared spectroscopy (NIRS) and the polysomnographic changes during sleep. Four healthy male volunteers participated in the study. Near-infrared spectroscopy measuring and polysomnographic recordings were done simultaneously during sleep. In many case, oxy-hemoglobin (oxy-Hb) decreased and deoxy-hemoglobin (deoxy-Hb) increased during the transition from wakefulness to sleep, and oxy-Hb increased toward deep sleep. Oxy-Hb and deoxy-Hb had larger fluctuations during REM sleep than those during non-REM sleep. During REM sleep, oxy-Hb often showed a lower level and deoxy-Hb showed a higher level than those during the preceding and following non-REM sleep.

Adult↗

PubMed1998

Whole sequence of spoIIIE-like, sporulation-inhibitory, and transfer gene (spi) in a conjugative plasmid, pSA1.1, of Streptomyces azureus and detection of spi-like gene in the actinomycete chromosome.

The nucleotide sequence of spoIIIE-like and the sporulation-inhibitory and transfer gene (spi) in a conjugative plasmid, pSA1.1, of Streptomyces azureus were examined to detect the promoter region. Using Southern blotting and a spi fragment as probe, spi-like genes were detected in chromosomes of the host and other actinomycetes. These results suggest that there is a spi- and spoIIIE-like gene in chromosomes of some actinomycetes.

Actinomycetales↗

PubMed1998

Apoptosis induced by niacin-related compounds in HL-60 cells.

We have investigated whether niacin-related compounds act as inducers of apoptosis in HL-60 cells. In this study, we found that picolinic acid, dipicolinic acid, and isonicotinamide strongly induce apoptosis. After treatments with these compounds, apoptosis started within 4 h and was induced in about 50% of the cells within 8 h. These compounds induced apoptosis at 5-10 mM, but did not at 1 mM. An ICE-like protease inhibitor (Z-Asp-CH2-DCB) completely blocked the apoptosis, but a caspase-1 inhibitor (Ac-YVAD-CHO) and a caspase-3 inhibitor (Ac-DEVD-CHO) did not block the apoptosis, suggesting that other caspases have the critical roles in the execution process of apoptosis induced by niacin-related compounds.

Apoptosis↗

PubMed1998

[Characteristics and progress of treatment for gastric cancers detected by mass screening].

We devised an X-ray examination to detect early gastric cancer, especially small gastric cancer, during the period between 1996 and 1997. As a result, the rate of gastric cancer detection by mass screening was 0.50%; and the rate of early gastric cancer detection was 79%. 1. Characteristics of gastric cancer detected by mass screening: Characteristics of gastric cancer were depressive-type undifferentiated cancer less than 4.0 cm diameter in work-place screening and depressive-type differentiated cancer less than 4.0 cm in area screening; 2. gastric cancer less than 2.0 cm in diameter was 75 (68%) of the 110 cases (total detected gastric cancer). 2) We have to consider that gastric cancer differs by sex and age. 3) EMR accounted for 39 (35%) of the 110 cases in treatment. This method resulted in a higher gastric cancer detection rate and served to maintain QOL.

Endoscopy↗

PubMed1997

Cloning and sequencing of the hup gene encoding the histone-like protein HSl of Streptomyces lividans.

The hup gene encoding the histone-like HU-type protein HSl of Streptomyces lividans TK24 was cloned and sequenced. The deduced N-terminal amino acid sequence, molecular mass (9851 Da) and pI (9.95) are in good agreement with characteristics of the HSI protein. The hup transcript of about 500 nucleotides was detected. The 2.3-kb HincII fragment containing the hup gene hybridized with the AseI fragment C in the 9-10 o'clock region of the chromosome of S. lividans ZX7.

Amino Acid Sequence↗

PubMed1997

Purification, characterization and partial primary structure of morphine 6-dehydrogenase from rabbit liver cytosol.

Morphinone, a toxic metabolite, was formed from morphine by NAD(P)-dependent morphine 6-dehydrogenase(s) in both the cytosol and microsomal fractions of the rabbit liver at pH 7.4. The enzyme activity in the cytosol fraction was about twice that in the microsomal fraction and NAD served as the preferred cofactor in both fractions. The enzyme in the cytosol fraction was purified to a homogeneous protein by the use of various chromatographic techniques. The enzyme is a monomeric protein with a molecular weight of 36,000 and an isoelectric point of 6.4. The enzyme had a dual cofactor specificity but NAD was more efficiently utilized than NADP. With NAD, the enzyme showed an optimal pH of 9.4, and the Km and Vmax values toward morphine were 0.72 mM and 0.59 unit/mg protein, respectively. The enzyme also exhibited a significant activity for morphine analogs having an unsaturated bond at C-7,8 (codeine, ethylmorphine, and normorphine), alicyclic alcohols (3-hydroxyhexobarbital, 1-indanol, and cyclohexene-2-ol) and benzenedihydrodiol. In the reverse reaction, the enzyme exhibited highly restricted specificity for o-quinones. Sulfhydryl re-agents and quercetin inhibited the enzyme but pyrazole, barbital, and indomethacin had little effect on the enzyme activity. Androstanes, lithocholic acid, and estradiol potently inhibited the enzyme in a competitive manner toward morphine binding. The partial amino acid sequence of the random peptides obtained by the proteolytic digestion of the enzyme, which comprised about 40% of the whole protein, revealed a significant homology to the corresponding regions in the members of the aldo-keto reductase family. These results therefore indicate that the present enzyme is a new and unique member of the aldo-keto reductase family.

Alcohol Oxidoreductases↗

PubMed1997

Absence of measles virus receptor (CD46) in lesions of subacute sclerosing panencephalitis brains.

In this study we investigated pathological changes of the expression of the measles virus (MV) receptor, CD46, in subacute sclerosing panencephalitis (SSPE) brains. We analyzed CD46 expression in lesions of brain specimens from five SSPE patients in comparison to uninfected regions of the same brains and to normal human brains. The correlation between CD46 and MV infection, in individual cells in SSPE brains, was analyzed by double-staining procedures using monoclonal antibodies (mAbs) and in situ hybridization to detect MV-specific mRNAs. We found that CD46 was expressed at relatively low levels by neurons and astrocytes in normal brains in comparison to neuroblastoma and astrocytoma cell lines. Within heavily infected (MV-positive) brain lesions of all five SSPE cases, CD46 was either not detected or was expressed to a lesser degree by neural cells, irrespective of whether MV antigens were detectable or not. In contrast, normal levels of CD46 were found in SSPE brain tissue distant from the lesion. Using in situ hybridization, mRNAs of both MV nucleocapsid and MV hemagglutinin (MV-H) were detected in all SSPE lesions, while no or only small amounts of MV-H protein were detected. MV-infected neurons were never found to express CD46. Although a strict correlation between levels of the MV-H protein and the absence CD46 could not be seen, these findings suggest that the CD46 expression is reduced by the MV infection in lesions of SSPE brains.

Adolescent↗

PubMed1997

Flow cytometric analysis for adhesion of Vibrio cholerae to human intestinal epithelial cell.

The adhesion of Vibrio cholerae O1 strains to human intestinal epithelial cell, Intestine 407, was analyzed by flow cytometer. According to positive percentages of Intestine 407 cells adhered by V. cholerae, two groups of V. cholerae strains were classified as follows: more adhesive (more than 50%), less adhesive (less than 50%) strains. In addition, the fluorescence intensity after attachment of V. cholerae was directly correlated to the number of the microorganisms. It was concluded that flow cytometry is a useful and objective method for analyzing adhesion of V. cholerae to cultured cells.

Bacterial Adhesion↗

PubMed1997

Metastatic cancer involving pancreatic duct epithelium and its mimicry of primary pancreatic cancer.

We investigated 47 autopsy cases of metastatic cancer involving the pancreas. Metastatic disease in nine cases involved the pancreatic duct epithelium. In two cases, metastatic cancer cells showed Pagetoid features. In three cases, pancreatic metastatic disease showed solitary proliferation with focal in situ carcinoma-like lesions mimicking primary pancreatic cancers. Each of these three cases had primary lung adenocarcinomas. Serial sections revealed abrupt borders between the in situ carcinoma-like lesions and the non-cancerous epithelium. Primary pancreatic cancers did not show Pagetoid features or abrupt borders between the cancerous and non-cancerous epithelium. We conclude that the possible diagnosis of pancreatic metastasis should be carefully ruled out in the histological detection of latent primary pancreatic cancer.

Aged↗

PubMed1997

Modification of spontaneous renal lesion of APA hamsters by streptozotocin-induced diabetes.

Syrian hamsters of the APA strain (APA hamsters) develop spontaneous mesangial thickening in the renal glomeruli from an early age. They also develop focal and segmental glomerulosclerosis (FSG) at and after 6 months of age. In this study, histopathological, immunohistochemical and lectin histochemical examinations were conducted to clarify the modification of the spontaneous renal lesions of APA hamsters by streptozotocin(SZ)-induced diabetes. Histopathological analysis revealed that the expansion of the mesangial region was more prominent and the thickening of the glomerular basement membrane (GBM) was weaker in SZ-treated animals than in non-treated ones. Immunohistochemical analysis suggested that type IV collagen and laminin were involved in the expansion of the mesangial region and thickening of the GBM. In lectin histochemical analysis, podocytes, capillary endothelial cells, GBM and a part of mesangial region of SZ-treated animals were positive for RCA120 and GSL-I with neuraminidase-pretreatment although they were negative for these lectins in non-treated animals. These results suggest that the spontaneous glomerular lesion of APA hamsters is modified qualitatively and quantitatively by SZ-induced diabetes.

Animals↗

PubMed1997

Purification and characterization of a kinin- and angiotensin II-forming enzyme in the dog heart.

OBJECTIVE: To purify and characterize a kinin-forming enzyme in the dog heart and to examine the ability of this enzyme to generate angiotensin (Ang) II from Ang I. METHODS: The enzyme was isolated from heart homogenate using a diethylaminoethyl-Sepharose column, an aprotinin affinity column and a wheat germ lectin-Sepharose 6MB column. Kininogenase activity was assessed with a kinin radioimmunoassay after samples had been incubated with bovine low-molecular-mass kininogen at 37 degrees C for 1 h. Ang I-converting activity was assessed by the quantitation of Ang II formed by incubation of the sample with Ang I at 37 degrees C for 3 h, using high performance liquid chromatography. The enzyme was subjected to 12.5% sodium dodecyl sulphate-polyacrylamide gel electrophoresis, stained by Coomassie brilliant blue and transferred electrically to a membrane with glycoprotein staining. RESULTS: The purified enzyme is a glycoprotein with an apparent relative molecular mass of 65 kDa by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Its kininogenase activity was approximately 20 micrograms bradykinin/h per mg protein at an optimal pH of 8.0. The enzyme also converted Ang I to Ang II at an optimal pH of 6.5. Its specific activity was approximately 2 micrograms Ang II/h per mg protein. Both activities were inhibited by aprotinin, a tissue kallikrein inhibitor. Western blot analysis using polyclonal antibody against this enzyme demonstrated that this enzyme exists both in the myocardium and in the coronary artery. CONCLUSIONS: The present study showed that the kinin-forming enzyme in the dog heart is a kallikrein-like enzyme that is different from cathepsin D, cathepsin G and chymase. It is also able to Ang I to Ang II. This enzyme might play a role in regulating myocardial perfusion, mainly by generating kinins and in part by forming Ang II.

Angiotensin II↗

PubMed1997

Studies on the relationship between adhesive activity and haemagglutination by Helicobacter pylori.

The adhesion of Helicobacter pylori to gastric carcinoma cells (MKN45, KatoIII and MKN28) and Intestine-407 cells was tested by flow cytometric analysis. The mean adhesion rates of H. pylori strains to MKN45, KatoIII and Intestine-407 cells were 90.5, 42.7 and 15.1%, respectively. There was no statistical correlation between the adhesion rates to MKN45 cells and haemagglutination (HA) activity of H. pylori strains, although H. pylori strains with high HA activity with human type O erythrocytes tended to adhere effectively to MKN45 cells. No correlation between adhesion and production of vacuolating toxin was observed.

Animals↗

PubMed1997

Gastric stump carcinosarcoma with rhabdomyosarcomatous differentiation.

Gastric carcinosarcoma is an unusual tumor and its occurrence in the gastric stump is extremely rare. A report is presented here of a unique case of gastric stump carcinosarcoma with rhabdomyosarcomatous differentiation in a 74-year-old man. The patient had undergone partial gastrectomy with gastrojejunostomy (Billroth II method) 30 years previously. The tumor had both adenocarcinoma and sarcoma components, and an immunohistochemical study suggested a focal transition between these components. The main sarcomatous components showed fibrosarcomatous features with a scattered distribution of rounded tumor cells, whose rhabdomyosarcomatous differentiation was immunohistochemically determined. Ultrastructural examination supported the rhabdomyosarcomatous natures. Experience with the present tumor indicates that carcinosarcoma with rhabdomyosarcomatous differentiation can occur in the gastric stump and that this disease is capable of aggressive behavior.

Aged↗

PubMed1997

The Yersinia enterocolitica GsrA stress protein, involved in intracellular survival, is induced by macrophage phagocytosis.

The Yersinia enterocolitica gsrA gene is a stress protein gene which was originally identified as essential for protecting cells under both extracellular environmental stress and intracellular stress in macrophages due to phagocytosis. The gsrA gene was shown to be a member of the htrA class of genes and to possess a sequence homologous to that of the promoter recognized by a stress-induced sigma factor, sigmaE. In order to study the induction of the potentially sigmaE-controlled gsrA gene in Y. enterocolitica after phagocytosis by macrophages, we identified GsrA by overproducing the protein using a T7 promoter-gsrA fusion. We found that it is translated as an unstable 49,500-Da protein which is processed by removal of an amino acid fragment consisting of 27 residues, resulting in a stable 46,800-Da protein. By radiolabeling proteins specific to bacteria in the J774-1 macrophage-like cell line, we found that the production of GsrA protein is indeed enhanced in bacterial cells growing within macrophage phagosomes. Transcriptional activation of the gsrA gene was determined by using the gsrA promoter-lacZ fusion system. This work provides the first piece of evidence that the sigmaE regulon responds to the stressful environment found in macrophages.

Animals↗

PubMed1997

Precise ultrastructural localization of endothelial leukocyte adhesion molecule-1, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1 in patients with IgA nephropathy.

Using light and electron microscopy, we performed an immunohistochemical study of endothelial leukocyte adhesion molecule-1 (ELAM-1), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) in 15 patients with IgA nephropathy to clarify the localization of these adhesion molecules. The normal portions of 2 kidneys removed due to localized carcinoma and 3 biopsies from patients without glomerular disease were used as a control. By light microscopy, ELAM-1, VCAM-1, and ICAM-1 all showed positive staining in IgA nephropathy, with the intensity of staining following the sequence ICAM-1 > VCAM-1 > ELAM-1. ELAM-1 and VCAM-1 showed a patchy distribution of moderate staining in the tissues, including the mesangium, crescents, adhesions, and tubules. In contrast, there was marked linear ICAM-1 staining throughout the vascular walls. ELAM-1 and VCAM-1 were positive on the basolateral surfaces of a few proximal tubular epithelial cells in association with inflammatory cell infiltration, while ICAM-1 was found on the brush border. ICAM-1 was positive in the glomerular capillary walls and interstitial vessels of the control kidney tissue, while ELAM-1 and VCAM-1 were virtually absent. By electron microscopy, ELAM-1 positivity on the urinary surface of the parietal/visceral epithelial cells was often associated with adherent mononuclear cells in the urinary space. VCAM-1 positivity was increased in the perinuclear space and/or cytoplasm of mesangial cells as well as at the mesangial cell-endothelial cell interface. These findings suggest that ELAM-1 and VCAM-1 may be more closely related than ICAM-1 to the major histopathological changes occurring in IgA nephropathy, including mesangial expansion, formation of crescents and adhesions, and tubulointerstitial injury.

Adolescent↗