Structure of Si(001) surfaces. I. The origin of the buckling in the dimer formation on reconstructed surfaces.
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Journal Article↗
Biomedical subjects
S Oikawa
Publications and source records attributed to S Oikawa.
Structure of Si(001) surfaces. II. The electronic structure of the symmetric dimer in the ground state.
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Journal Article↗
Regional chromosomal assignment of carcinoembryonic antigen gene (CEA) to chromosome 19 at band q13.2.
Carcinoembryonic antigen (CEA), a glycoprotein, is one of the most widely used human tumor markers. It is a member of a gene family comprising about 10 closely related genes and might be found throughout mammalians. Recently, two parts of a genomic DNA for CEA were isolated and sequenced. Using these genomic DNA fragments as probes we assigned the human CEA gene to chromosome 19 at the band q13.2 by in situ hybridization.
Carcinoembryonic Antigen↗
Molecular cloning of nonspecific cross-reacting antigens in human granulocytes.
To clarify the molecular structures of nonspecific cross-reacting antigens (NCAs), a family of glycoproteins antigenically related to carcinoembryonic antigen (CEA), in human granulocytes, we have screened a cDNA library of human leukocytes using a cDNA probe for the N-terminal domain (domain-N) of NCA-50, an NCA species in tumor cells. In 95 positive clones randomly selected, we identified six NCA or NCA-related cDNA clones including NCA-50, biliary glycoprotein protein a, and W272 (CGM6) which have previously been reported, and three new clones, W236, W264, and W282, encoding three novel NCA species. W236 and W264 consist of a domain-N, a putative transmembrane domain, and a possible cytoplasmic domain. The domain-N of W264 is 89% similar to that of NCA-50 at amino acid level, whereas the domain-N of W236 is only 49 and 43% similar to those of NCA-50 and pregnancy-specific beta 1-glycoprotein-11 (PSG11), respectively, indicating that W236 belongs to a new subfamily within the CEA family. The third clone W282 encodes a protein consisting of a domain-N virtually identical to that of W264 and a short hydrophilic C-terminal domain. W264 and W282 seem to be derived from a single gene by alternative splicing of RNA. These three new species are particularly unique in respect that they lack the repetitive immunoglobulin-related domains that have been universally found in the human CEA gene family members. The biochemical and immunochemical properties of the recombinant proteins of these cDNA clones, however, did not coincide with those of six NCA species previously identified in granulocytes at protein level, suggesting that, in granulocytes, there exist at least 12 NCA or NCA-related species whose expression is under complex control.
Amino Acid Sequence↗
A specific heterotypic cell adhesion activity between members of carcinoembryonic antigen family, W272 and NCA, is mediated by N-domains.
The Ca(2+)-independent homotypic and heterotypic cell adhesion activities of a carcinoembryonic antigen (CEA) family member, W272 (CGM6), whose cDNA has recently been isolated from libraries of human peripheral leukocytes of apparently normal subjects (Arakawa, F., Kuroki, Mo., Misumi, Y., Oikawa, S., Nakazato, H., and Matsuoka, Y. (1990) Biochem. Biophys. Res. Commun. 166, 1063-1071) and spleen of chronic myelogenous leukemia patients (Berling, B., Kolbinger, F., Grunert, F., Thompson, J. A., Brombacher, F., Buchegger, F., von Kleist, S., and Zimmermann, W. (1990) Cancer Res. 50, 6534-6539) has been examined. Chinese hamster ovary cells transfected with the cDNA for W272, CEA, nonspecific cross-reacting antigen (NCA), and various antigens containing chimeric N-domain have been used. The W272 producers did not show homotypic binding at all but bound only to the cells expressing NCA and a chimeric CEA whose N-domain is substituted by that of NCA, indicating the major contribution of N-domain of NCA in the specific binding. The importance of the N-terminal region of NCA N-domain for the W272-NCA binding has been shown by detailed analysis using COS-1 cells producing various NCA whose N-domain are chimera of that of NCA and CEA. The strict heterotypic nature of the W272-NCA adhesion strongly suggests that the cell adhesion activities exhibited by CEA family members are not the fortuitous activity but the specific one which have some important physiological roles.
Amino Acid Sequence↗
Three novel molecular forms of biliary glycoprotein deduced from cDNA clones from a human leukocyte library.
Three cDNA clones that encode three novel variants of biliary glycoprotein a (BGPa), a glycoprotein belonging to the CEA gene family, were identified in a human leukocyte cDNA library. The domain structures of the predicted proteins of the three clones W211, W233 and W239 are N-A1-B1-A2, N-A1-B1 and N-A1-B1-C, respectively; they lack the transmembrane and cytoplasmic domains that exist in the four BGP species (BGPa, BGPb, BGPc and BGPd) previously reported. Their sequences from N to B1 or to A2 are virtually identical to those of BGPa-d. Comparison with the genomic sequence for BGPa-d suggested that these three new BGP variants as well as BGPa-d are generated from the same single gene by alternative splicing of RNA.
Antigens, CD↗
Preparation and characterization of monoclonal antibodies specific to synthetic peptide of carcinoembryonic antigen.
Monoclonal antibodies (MAbs) were prepared to a synthetic peptide (PI: 119-140 amino acids) in domain 1 of the carcino-embryonic antigen (CEA) molecule. The majority of the amino acids in peptide PI show a hydrophilic character, and similar sequences are repeated in domains I, II and III of this molecule. These MAbs appear to recognize new epitopes of CEA, since representative conventional MAbs to CEA do not show reactivity to synthetic peptide PI. The resulting MAbs were divided into 2 groups; group 1 (MAb PI-706) reacted with peptide PI, but not with purified CEA preparation, while group 2 (MAb PI-234 and PI-255) reacted with either type of antigen, in the immunoblotting assay using purified CEA and in immunostaining of colonic carcinoma tissues. Furthermore, group-1 MAb PI-706 was reactive to purified CEA after treatment with periodate.
Amino Acid Sequence↗
Abnormal lipoprotein and apolipoprotein pattern in lipoprotein glomerulopathy.
Recently, two cases of renal disease were observed in which there was an abnormal accumulation of lipids, "lipoprotein thrombi," in the glomerular capillary lumen. This disease has been designated as lipoprotein glomerulopathy. Four other cases have been diagnosed independently by renal histology in other clinical laboratories. All six patients showed proteinuria (1.6 to 10 g/d), normal lecithin-cholesterol acyltransferase (LCAT) activity, type III hyperlipoproteinemia-like lipoprotein profiles, and significantly (P less than 0.01) higher levels of plasma apolipoprotein (apo) E (greater than 10 mg/dL) compared with the control patients with hyperlipidemic nephrotic syndrome without lipoprotein thrombi and type IIb hyperlipoproteinemia without renal disease. Lipoprotein glomerulopathy is not familial type III hyperlipoproteinemia (dysbetalipoproteinemia), because apolipoprotein E3 is present. Apo E isoforms were all rare: five cases of E2/3 and one case of E4/4. These results suggest that excessive apo E is associated with apo E isoform and lipoprotein metabolic derangement in such a renal disease. Further studies are needed on the relationship between the apo E hyperlipoproteinemia and the formation of lipoprotein thrombi.
Adult↗
Establishment and characterisation of human carcinoembryonic antigen transgenic mice.
We have produced human CEA transgenic mice which were found to express CEA mRNA in all tissues. By immunoblot analysis using anti-CEA polyclonal antibody, we also detected CEA protein in all tissues. However, the molecular size of CEA in the brain was different from that in other tissues, although the mRNA size was same and no deletion nor rearrangement was detected at the DNA level. Immunohistochemical analysis of the lung and the colon showed that the expression sites were the bronchial epithelial cells of the lung and the columnar epithelial cells of the colon. Interestingly, the expression of CEA protein in the transgenic mice was polarised to the luminal side of epithelial cells similar to the normal CEA expression in human tissues. We also detected cell surface expression of human CEA on thymocytes and spleen cells and CEA expression was greatly reduced by the phosphatidylinositol-specific phospholipase C (PI-PLC) treatment.
Animals↗
Oxidative degradation of an antitumor (1-3)-beta-D-glucan, grifolan.
A (1-3)-beta-D-glucan, grifolan (GRN), recovered from the peritoneal cavity after 1 d from i.p. injection contained a significant amount of anionic metabolite(s) having lower Mr than the parent GRN. In parallel with this observation, GRN induced peritoneal exudate cells exhibiting a higher level of oxidative burst than the non-stimulated, resident peritoneal cells. Chemical oxidation of GRN by active oxygen species such as (a) ascorbic acid-CuSO4, (b) hydrogen peroxide, (c) hydrogen peroxide-CuSO4, or (d) hypochlorous acid also produced anionic as well as lower Mr degradation products. Under these experimental conditions the structural changes were remarkable and in the order of a less than b less than c less than d. The products formed under the conditions (a) and (b) retained significant antitumor activity but those of (c) and (d) lost the activity. However, oxidation product(s) of curdlan, an antitumor inactive (1-3)-beta-D-glucan having no branch, by condition (d) induced significant antitumor activity. These results suggested that oxidative degradation of (1-3)-beta-D-glucans produced some temporary active metabolites and then gradually changed to the inactive form. However, these active metabolites contribute less than the parent glucan on the whole activation mechanisms of the host by (1-3)-beta-D-glucans.
Animals↗
Inhibition of experimental pulmonary metastasis of Lewis lung carcinoma by orally administered beta-glucan in mice.
The inhibitory effect on experimental pulmonary metastasis of Lewis lung carcinoma (3LL) of SSG, a (1----3)-beta-D-glucan obtained from the fungus Sclerotinia sclerotiorum IFO 9395, administered orally was examined in mice. Oral administration of SSG for 10 consecutive days just after the intravenous implantation of tumor cells significantly inhibited the experimental pulmonary metastasis of 3LL at a dose of 2000 micrograms. However, SSG administered orally involving other timings was less effective. In comparison with oral administration, SSG was effective when administered intraperitoneally for 10 consecutive days at a dose of 200 micrograms. These results suggest that SSG given by both parenteral and nonparenteral routes is effective in the inhibition of experimental pulmonary metastasis of tumors.
Animals↗
Effect of intraperitoneally administered beta-1,3-glucan, SSG, obtained from Sclerotinia sclerotiorum IFO 9395 on the functions of murine alveolar macrophages.
The effect of intraperitoneally (i.p.) administered SSG, a beta-1,3-glucan obtained from the culture filtrate of the fungus Sclerotinia sclerotiorum IFO 9395, on the functions of alveolar macrophages (AM) in CDF1 mice was examined. SSG administered i.p. increased the number of AM and enhanced several functions of murine AM (lysosomal enzyme activity, phagocytic activity, candidacidal activity, H2O2 production and interleukin 1 (IL-1) production) at a dose of 250 micrograms/mouse on days 1 and 8, especially on day 8. Furthermore, SSG (250 micrograms/mouse) administered i.p. for 10 consecutive days significantly inhibited the experimental pulmonary metastasis of Lewis Lung Carcinoma (3LL) on BDF1 mice.
Animals↗
[Obesity and chronic complications of diabetes mellitus].
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Arteriosclerosis↗
Reactivity of Limulus amoebocyte lysate towards (1----3)-beta-D-glucans.
The structure activity relationship for beta-D-glucans for the gelation of the amoebocyte lysates of the horseshoe crab (Limulus) has been investigated. beta-D-Glucans that had no (1----3) linkages induced little or no gelation. The (1----3)-beta-D-glucans curdlan (unbranched), grifolan (approximately 33% branched), schizophyllan (approximately 33% branched), lentinan (approximately 40% branched). SSG (approximately 50% branched), and OL-2 (approximately 66% branched) induced significant gelation. The optimum concentration for gelation was correlated with the content of branching. Single chain (rather than a triple helix) conformation and higher molecular weight were associated with higher reactivity.
Animals↗
Identification of membrane anchoring site of human renal dipeptidase and construction and expression of a cDNA for its secretory form.
The chemical properties of human renal dipeptidase (hrDP) purified from the membrane fraction of kidney have been characterized. When treated with phosphatidylinositol-specific phospholipase C, hrDP was released from renal membrane fractions. After digestion with trypsin, carboxyl-terminal peptide was isolated employing anhydrotrypsin-agarose column chromatography and reversed-phase high performance liquid chromatography. The amino acid sequence of the peptide was identified at positions 363-369 in the primary structure deduced from the cDNA sequence (Adachi, H., Tawaragi, Y., Inuzuka, C., Kubota, I., Tsujimoto, M., Nishihara, T., And Nakazato, H. (1990) J. Biol. Chem. 265, 3992-3995). Further examination of the chemical composion of the peptide showed that it contained, respectively, 2, 1, 5, 1, and 1 mol of ethanolamine, glucosamine, mannose, inositol, and phosphate in addition to amino acids. These results suggest that the mature hrDP molecule lacks the carboxyl-terminal hydrophobic peptide extension predicted from the cDNA sequence and is anchored at Ser369 via glycosylphosphatidylinositol to the membrane. To characterize further the action of the enzyme, we have established expression systems for both secretory and membrane anchored forms of hrDP using COS-1 cells and found that both recombinant forms were as active as natural enzyme. Our expression system made it possible to prepare large amounts of soluble enzyme, and will contribute toward elucidation of the physiological roles of the enzyme.
Amino Acid Sequence↗
Expression of complementary DNA and genomic clones for carcinoembryonic antigen and nonspecific cross-reacting antigen in Chinese hamster ovary and mouse fibroblast cells and characterization of the membrane-expressed products.
Complementary DNA clones coding for both carcinoembryonic antigen (CEA), a well characterized colonic tumor marker, and nonspecific cross-reacting antigen (NCA), a related antigen, were expressed in Chinese hamster ovary (CHO) cells and L-cells (mouse fibroblasts). A genomic clone coding for CEA was also expressed in CHO cells. Positive clones were identified by fluorescence flow cytometry and enzyme-linked immunosorbent assay. Membrane location of the recombinant CEA and NCA was confirmed by indirect immunofluorescence labeling of the transfectants, followed by visualization under a fluorescence microscope. The apparent molecular weight of the expressed CEA and NCA were 180,000 and 96,000, respectively, for both cell lines, as determined by immunoblot analysis. The CEA and NCA expressed on CHO cells were sensitive to treatment with phosphatidylinositol-specific phospholipase C (PI-PLC), whereas the CEA and NCA proteins on L-cells were resistant to removal by PI-PLC. Unlike NCA, which contains three methionine residues, the only methionine in CEA is in the C-terminal hydrophobic domain. This domain in CEA was shown to be removed and replaced by a phosphatidylinositol glycan (PI-G) anchor (Hefta et al., Proc. Natl. Acad. Sci. USA, 85: 4648-4652, 1988). The recombinant CEA from both CHO cells and L-cells could be labeled with [3H]-ethanolamine (a component of the PI-G anchor) but not with [35S] methionine, whereas the recombinant NCA could be labeled with both [3H]ethanolamine and [35S]methionine. The labeling studies and PI-PLC treatment results are consistent with the CEA and NCA expressed on CHO cells possessing a PI-G anchor. The CEA expressed on the L-cell transfectants may contain a PI-G anchor which is resistant to cleavage by PI-PLC. In addition, the membrane-bound and secreted levels of CEA from the CHO and L-cell transfectants were determined.
Animals↗
Characterization of a cDNA clone encoding a new species of the nonspecific cross-reacting antigen (NCA), a member of the CEA gene family.
To clarify the molecular structures of the nonspecific cross-reacting antigens (NCAs) produced by human granulocytes, we cloned cDNAs from libraries of normal white blood cells. A clone, NCA-W272, was found to code a protein similar to NCA of tumor cells. The protein consisted of a signal peptide (34 aa), domain-N (108 aa), -A1 (92 aa), -B1 (86 aa) and -M (29 aa). Similarity of the amino acid sequence of each domain to that of the tumor NCA was 72, 92, 76 and 79%, respectively. COS-1 cells transfected with an expression vector carrying the cDNA synthesized a 70 kDa glycoprotein, which was reactive with anti-NCA antibody and released from cell surface by phosphatidylinositol-specific phospholipase C. Thus the clone NCA-W272 was indicated to encode a new species of NCA distinct from the tumor NCA.
Amino Acid Sequence↗
Determination of lipid hydroperoxides in low density lipoprotein from human plasma using high performance liquid chromatography with chemiluminescence detection.
A high performance liquid chromatographic system with chemiluminescence detection (HPLC-CL) was used for determining phospholipid hydroperoxides in human plasma low density lipoprotein (LDL). This system involved separation of phospholipids from LDL-total lipids with normal phase silica gel HPLC and post-column detection of hydroperoxide-dependent chemiluminescence produced by luminol oxidation during the reaction of hydroperoxide with cytochrome c-haeme. By using HPLC-CL, we could detect phosphatidylcholine hydroperoxide (PCOOH) in human plasma LDL, and the LDL-PCOOH concentration was significantly higher in patients with atherosclerosis and hyperlipidemia than that of healthy volunteers. The LDL-PCOOH level was proportional to the plasma total cholesterol concentration.
Adolescent↗