Biomedical subjects

K Kitajima

Publications and source records attributed to K Kitajima.

At least 73 records · Page 4Linked to original sources

PubMed1999

Successful cytokine treatment of aplastic anemia following living-related orthotopic liver transplantation for non-A, non-B, non-C hepatitis.

The relationship between aplastic anemia and viral hepatitis is well recognized, and such patients usually have a high mortality. We successfully treated a case of aplastic anemia following living-related orthotopic liver transplantation (LROLT) for non-A, non-B, non-C hepatitis. A 2-yr-old boy with fulminant hepatic failure from non-A, non-B, non-C hepatitis received LROLT. Before transplantation, he had pancytopenia which was probably hepatitis associated, and viral suppression was suspected after bone marrow (BM) biopsy. After the transplantation, he developed progressive pancytopenia and a diagnosis of aplastic anemia was made via BM biopsy. With immunosuppressant agents (cyclosporine, methylprednisolone), cytokine therapy (granulocyte-colony stimulating factor (G-CSF), macrophage-colony stimulating factor (M-CSF), recombinant human erythropoietin (rhEPO)) was effectual and the patient recovered from pancytopenia. He was discharged from the hospital 57 d after the liver transplantation and remains well 1 yr after LROLT. Combined cytokine therapy with high doses of G-CSF, M-CSF and rhEPO appeared to be effective in the treatment of aplastic anemia following liver transplantation for non-A, non-B, non-C hepatitis. Since M-CSF activates macrophages, it may have contributed to the graft rejection. Careful consideration should be given to the use of high-dose M-CSF in liver transplant patients.

Anemia, Aplastic↗

PubMed1999

A 42-kDa glycoprotein from chicken egg-envelope, an avian homolog of the ZPC family glycoproteins in mammalian Zona pellucida. Its first identification, cDNA cloning and granulosa cell-specific expression.

A glycoprotein with molecular mass of 42 kDa was identified as the major component of the chicken egg-envelope, the filamentous, extracellular matrix known as the perivitelline layer. By using a DNA probe amplified with degenerative primers derived from the protein's partial amino acid sequences, a cDNA clone encoding the egg-envelope 42-kDa glycoprotein (gp42) was isolated from a hen's ovary cDNA library. The gp42 open reading frame encoded 435 amino acid residues, including a putative signal peptide of 20 amino acids. The deduced amino acid sequence of gp42 showed significant similarity to egg-envelope glycoproteins of the ZPC family of several other vertebrate species, including human ZP3, mouse ZP3, Xenopus laevis gp43 and medaka (Oryzias latipes) ZI3 (LS-F), which play important roles for sperm-egg interaction. A single N-glycosylation site present in chicken gp42 is conserved among all five of these proteins: carbohydrate analysis of gp42 revealed the presence of a complex type glycan chain at this site. N-terminal sequence analysis of the mature polypeptide suggests that C-terminal processing of the pro-protein occurs during synthesis and secretion. The 1.4-kb gp42 transcript was detected only in follicles, and was found to be accumulated in granulosa cells in a manner dependent on ovarian follicular development. Furthermore, a metabolically radio-labeled gp42 was immunopreciptated from both cell lysate and culture supernatant of the granulosa cells with specific anti-gp42 antibody, suggesting granulosa cell-specific synthesis and secretion of the glycoprotein.

Amino Acid Sequence↗

PubMed1999

Expression of inducible nitric oxide synthase in human thyroid papillary carcinomas.

To evaluate the relationship between nitric oxide (NO) and carcinogenesis, we assayed 4 human thyroid papillary carcinomas (TPC) and 3 normal thyroid glands for the presence of inducible nitric oxide synthase (iNOS). Using an antibody against iNOS, we observed immunohistochemical staining if iNOS in the TPC samples, but not in normal thyroid. When we incubated TPC samples with antibodies against both iNOS and human leukocyte antigen (LCA), a macrophage marker, we found that while most TPC cells were stained with anti-iNOS antibody, only a few were stained with both. Reverse transcription polymerase chain reaction (RT-PCR) showed that iNOS mRNA was expressed in the samples of TPC, but not in normal thyroid. The sequence of iNOS message in the TPC samples was identical to that previously detected in a human colon cancer cell line. These results suggest that iNOS in human TPC is mostly derived from tumor cells, rather than macrophages, and that it may play a direct role in carcinogenesis.

Base Sequence↗

PubMed1999

Identification of two discrete peptide: N-glycanases in Oryzias latipes during embryogenesis.

Two different types of peptide:N-glycanase (PNGase) were identified in developing embryos of medaka fish ( Oryzias latipes ). Because the optimum pH values for their activities were acidic and neutral, they were designated as acid PNGase M and neutral PNGase M, respectively. The acid PNGase M corresponded to the enzyme that had been partially purified from medaka embryos (Seko,A., Kitajima,K., Inoue,Y. and Inoue,S. (1991) J. Biol. Chem., 266, 22110-22114). The apparent molecular weight of this enzyme was 150 K, and the optimal pH was 3.5-4.0, and the K m for L-hyosophorin was 44 microM. L-Hyosophorin is a cortical alveolus-derived glycononapeptide with a large N-linked glycan chain present in the perivitelline space of the developing embryo. Acid PNGase M was competitively inhibited by a free de-N-glycosylated nonapeptide derived from L-hyosophorin. This enzyme was expressed in ovaries and embryos at all developmental stages after gastrulation, but activity was not detected in embryos at developmental stages between fertilization and gastrula. Several independent lines of evidence suggested that acid PNGase M may be responsible for the unusual accumulation of free N-glycans derived from yolk glycoproteins (Iwasaki,M., Seko,A., Kitajima,K., Inoue,Y. and Inoue,S. (1992) J. Biol. Chem., 267, 24287-24296). In contrast, the neutral PNGase M was expressed in blastoderms from the 4-8 cell stage and in cells up to early gastrula. The general significance of these findings is that they show a developmental stage-dependent expression of the two PNGase activities, and that expression of the neutral PNGase M activity occurs concomitantly with the de-N-glycosylation of L-hyosophorin. These data thus support our conclusion that the neutral PNGase M is responsible for the developmental-stage-related de-N-glycosylation of the L-hyosophorin.

Amidohydrolases↗

PubMed1999

Comparative study of vocal function after near-total laryngectomy.

OBJECTIVES: To assess vocal function after near-total laryngectomy (NTL) and to compare that with after vertical hemilaryngectomy (VHL), both of which use the laryngeal mucosa as the vibratory tissue. STUDY DESIGN: We retrospectively evaluated 29 patients, 11 of whom underwent NTL and 18 of whom underwent VHL. However, 2 patients failed to speak and 1 patient's voice sample was lost following NTL, so we analyzed the voices of 8 patients who underwent NTL and 18 patients who underwent VHL. METHODS: Vocal function was examined by acoustic and aerodynamic analysis. Acoustic analysis involved the evaluation of pitch, intensity, pitch perturbation quotient, amplitude perturbation quotient, and normalized noise energy. In aerodynamic analysis, we studied the mean airflow rate, vocal efficiency index (alternating current/direct current [AC/DC]), and maximum phonation time. RESULTS: Vocal function except pitch after either NTL or VHL had much variability, but the results following each procedure did not differ significantly. CONCLUSIONS: There are no significant differences between vocal function following NTL and VHL. Fiberscopic examination of the mucosa of the arytenoid was observed to vibrate in patients who underwent NTL, so that the phonatory mechanism after NTL resembled that after VHL.

Adult↗

PubMed1998

Peptides glycosylated in the endoplasmic reticulum of yeast are subsequently deglycosylated by a soluble peptide: N-glycanase activity.

Several lines of evidence suggest that soluble peptide:N-glycanase (PNGase) is involved in the quality control system for newly synthesized glycoproteins in mammalian cells. Here we report the occurrence of a soluble PNGase activity in Saccharomyces cerevisiae. The enzyme, which was recovered in the cytosolic fraction, has a neutral pH optimum, and dithiothreitol is required for activity. All of these properties were similar to those of earlier described for mammalian PNGases. Interestingly, the yeast enzyme activity was found to be present almost exclusively in cells in stationary phase; little activity was detected in logarithmic growth phase cells. Upon incubation of a glycosylatable peptide R-Asn-X-Thr-R' with permeabilized yeast spheroplasts, we detected formation of both glycosylated peptide and the peptide product expected from PNGase-mediated deglycosylation of this glycopeptide, namely, R-Asp-X-Thr-R'. Recent findings that yeast have an active system for the retrograde transport of unfolded (glyco)proteins and glycopeptides out of the endoplasmic reticulum (ER) into the cytosol raise the possibility that this PNGase may participate in an early step in degradation of these molecules following their export from the ER.

Amidohydrolases↗

PubMed1998

Development of a highly sensitive chemical method for detecting alpha2-->8-linked oligo/polysialic acid residues in glycoproteins blotted on the membrane.

A highly sensitive chemical method for detecting alpha2-->8-linked oligo/polysialic acid (oligo/polySia) chains was developed, including (i) periodate oxidation, reduction with sodium borohydride, and subsequent acid hydrolysis, giving rise to C7 analogues and intact C9 compounds from nonreducing terminal and internal sialic acid residues, respectively; (ii) fluorescent labeling of these C7 and C9 compounds with 1,2-diamino-4,5-methylenedioxybenzene (DMB); and (iii) quantitation of theseDMB derivatives on fluorometric high-performance liquid chromatography. As little as 1 ng of internal sialic acid residues of oligo/polySia chains, the existence of which indicates the presence of oligo/polySia structure, was detectable by this method. This fluorometric C7/C9 analysis was successfully applied to glycoproteins blotted onto a slit of polyvinylidene fluoride membranes and suggested the presence of some novel oligoSia-containing glycoproteins in pig embryonic brains.

Animals↗

PubMed1998

Induction of KDNase Sm, a deaminoneuraminic acid (KDN) residue-specific sialidase from Sphingobacterium multivorum, using synthetic KDN-glycosides.

Various aryl and alkyl alpha-glycosides of KDN were synthesized and tested as substrates for their susceptibility to a deaminoneuraminic acid (KDN)-specific sialidase from Sphingobacterium multivorum, designated KDNase Sm. The synthetic KDN-glycosides were all hydrolyzed by the action of KDNase Sm. A hydroxyl group at C-5 position of KDN was required for the recognition by the enzyme, and was shown not to be replaced by an amino- or an acylamino group for the enzymatic recognition. These synthetic KDN-glycosides were also examined for their inducing activity of KDNase in S. multivorum and were shown to induce the KDNase activity effectively when the bacterium was cultured minimum salt medium containing both 0.1% glucose and 0.1% various KDN-glycosides. No KDNase activity was induced by the KDN-glycosides without 0.1% glucose. This is the first case of using synthetic KDN-glycosides as inducers of KDNase Sm.

Carbohydrate Conformation↗

PubMed1998

RT-PCR analysis of mRNA expression of natriuretic peptide family and their receptors in rat inner ear.

To assess the possible physiological role of the atrial natriuretic peptide (ANP) family, we investigated the expression of mRNA of ANP, brain natriuretic peptide (BNP), C-type natriuretic peptide (CNP), and their receptors in rat inner ear using the reverse transcription-polymerase chain reaction method. ANP and CNP message bands were detected in the inner ear, but the BNP message band was not. Amplification products of the expected sizes of ANP-A, ANP-B and ANP-C receptors were detected in the inner ear. These results suggest that natriuretic peptide family may influence the function of the inner ear through the ANP-A, ANP-B, and ANP-C receptors.

Animals↗

PubMed1998

Development of an enzyme-linked immunosorbent assay-based method for measuring galactosyltransferase activity using a synthetic glycopolymer acceptor substrate.

A lectin-assisted enzyme-linked immunosorbent assay (ELISA)-based method using a synthetic glycopolymer as an acceptor substrate was developed for measuring beta 1,4-galactosyltransferase (GalT) activity. A polyacrylamide derivative having a beta-linked N-acetylglucosamine (GlcNAc beta) moiety on each monomeric unit was synthesized chemically and immobilized on a polystyrene microtiter plate as an acceptor substrate for GalT. After the plate was incubated with bovine GalT, the enzyme reaction product, beta-linked Gal residue on the polyacrylamide-bound GlcNAc residue, was detected by using Ricinus communis agglutinin 1 (RCA1), rabbit anti-RCA1 antibody, and a peroxidase-labeled anti-rabbit IgG. The lowest GalT concentration detectable by this method was about 0.5 mU/ml, which is comparable to those by the previously reported ELISA-based assays. The unique property of the glycopolymer, PAP(GlcNAc beta), of binding noncovalently but tightly to the polystyrene microtiter plate allowed the use of this acceptor substrate for the GalT activity measurement even in the presence of 1% Triton CF-54 and X-100. Our system was successfully applied to assess GalT activity in milk of various mammals.

Acetylglucosamine↗

PubMed1998

Identification of oligo-N-glycolylneuraminic acid residues in mammal-derived glycoproteins by a newly developed immunochemical reagent and biochemical methods.

The occurrence of the alpha2-->8-linked oligomeric form of N-glycolylneuraminic acid (oligo-Neu5Gc) residues in mammalian glycoproteins was unequivocally demonstrated using a newly developed anti-oligo/poly-Neu5Gc monoclonal antibody as well as by chemical and biochemical methods. First, the antibody, designated mAb.2-4B, which specifically recognized oligo/poly-Neu5Gc with a degree of polymerization of >2, was developed by establishing a hybridoma cell line from P3U1 myeloma cells fused with splenocytes from an MRL autoimmune mouse immunized with dipalmitoylphosphatidylethanolamine-conjugated oligo/poly-Neu5Gc. Second, oligo-Neu5Gc was shown to occur in glycoproteins derived from pig spleen by Western blot analysis using mAb.2-4B, which was also confirmed by fluorometric high performance liquid chromatographic analysis of the product of periodate oxidation/reduction/acid hydrolysis of the purified glycopeptide fractions and by TLC and 600-MHz 1H NMR spectroscopic analysis of their mild acid hydrolysates. Finally, the ubiquitous occurrence of oligo-Neu5Gc chains as glycoproteinaceous components in Wistar rat tissue was immunochemically indicated. This is the first example demonstrating the diversity in oligo/poly-Sia structure in mammalian glycoproteins, where only poly-N-acetylneuraminic acid is known to occur. Such diversity in oligo/poly-Sia structure also implicates a diverged array of biological functions of this glycan unit in glycoproteins.

Animals↗

PubMed1998