Search PubMed⌕ Search

Biomedical subjects

T Kitayama

Publications and source records attributed to T Kitayama.

At least 19 recordsLinked to original sources
PubMed2003

Analysis of long-chain polyprenols using supercritical fluid chromatography and matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

The separation of long-chain polyprenols was successfully achieved using supercritical fluid chromatography (SFC). Each 100-mer greater component was separated using tetrahydrofuran as a mobile phase modifier. The molecular mass distributions derived from SFC analyses agreed with the results of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analyses. The number-average molecular mass calculated by MALDI-TOF-MS data were also in accord with the results of quantitative 1H-NMR analysis of terminal groups. A combination of SFC and MALDI-TOF-MS analyses is a powerful tool for the elucidation of the complicated structures of natural polyprenols.

Chromatography, Supercritical Fluid↗
PubMed2003

Non-pathogenic bacteria modulate colonic epithelial gene expression in germ-free mice.

BACKGROUND: We established a bacterial reconstitution model to investigate epithelial cell-luminal bacteria interaction. The aim of the study was to identify the known genes directly or indirectly modulated by non-pathologic bacterial flora in the colonic epithelia of germ-free mice. METHODS: Germ-free mice were orally given a bacterial suspension prepared from specific pathogen-free counterparts (bacterial reconstitution). Colonic epithelial cells were isolated, then total and poly (A) RNA were extracted. We investigated differential gene expression in colonic epithelial cells among germ-free, bacteria-reconstituted, and specific pathogen-free mice by DNA microarray. Finally, differential expression was confirmed by Northern blot or quantitative RT-PCR. RESULTS: Thirty genes were initially selected as differentially expressed genes in DNA microarray analysis. We confirmed that genes associated with growth (Reg IIIbeta, Reg IIIgamma, guanylate nucleotide binding protein 2), apoptosis (Bcl-associated death promotor), cytoskeleton (tubulin alpha4, erythrocyte protein band 7.2), and immune response (lymphocyte antigen complex 6) were induced by bacterial reconstitution. In contrast, genes possibly participating in extracellular oxidant defence (selenoprotein P, metallothionein 1) and cellular metabolism (cytochrome P450, HMGCoA synthase 2, alcohol dehydrogenase 1 complex, aldehyde dehydrogenase family 1, carbonic anhydrase 1, glycoprotein galactosyltransferase alpha1,3) were down-regulated by bacterial challenge. CONCLUSION: Non-pathogenic bacteria modulated colonic gene expression in germ-free mice, suggesting that non-pathogenic bacteria possibly initiate epithelial change in genetically normal and/or abnormal hosts. The present study provides a basis for the functional study of each molecule in symbiosis with luminal bacteria in healthy and diseased colon.

Animals↗
PubMed2001

Unprecedented sugar-dependent in vivo antitumor activity of carbohydrate-pendant cis-diamminedichloroplatinum(II) complexes.

Eight carbohydrate-pendant platinum(II) complexes have been synthesized from carbohydrate-diamine conjugates. D-Glucose, D-mannose, D-galactose, D-xylose, and L-glucose are attached to the dichloroplatinum(II) moiety by 1,3- or 1,2-diaminopropane chelates through with an O-glycoside bond. All the carbohydrate moieties reduced the toxicity inherent with platinum(II) complexes.

Animals↗
PubMed2001

Sugar-pendant diamines.

A set of 1,3-propanediamine derivatives connected to carbohydrates (5) has been prepared in four steps from peracetylated sugar and 1,3-dibromo-2-propanol in 60-73% yields. D-Glucose, D-mannose, D-galactose, D-xylose, D-ribose, and maltose are utilized as sugar molecules in this work. The diamine moiety was connected to the C1 carbon of the glycopyranose ring via an O-glycoside bond. All of the anomeric configurations and sugar puckering conformations, except in the D-maltose derivative, were determined by X-ray crystallography of the diazido or dibromo precursors. While glycosidation of peracetylated galactopyranose with 1,3-dibromo-2-propanol in the presence of boron trifluoride afforded both anomers, the neighboring group participation of the 2-acetoxy group yielded a single anomer for the other substrates. This method has been used to synthesize a library of sugar-pendant diamines including an OH-protected derivative (6), and an N,N'-diisopropyl-substituted derivative (7). A similar series of reactions using 2,3-dibromo-1-propanol gave ethylenediamine-type derivatives (11), and bis(bromomethyl)bis(hydroxymethyl)methane (12) gave bisglucose-pendant derivatives (16).

Carbohydrate Sequence↗
PubMed2001

High-resolution analysis of polyprenols by supercritical fluid chromatography.

A high-resolution analysis of polyprenol mixtures was achieved by supercritical fluid chromatography (SFC). The separation of polyprenols was examined on an octadecylsilane-packed column with liquid carbon dioxide as the mobile phase and ethanol as modifier. Using this chromatography system, the resolution of separation (Rs) between octadecaprenol (prenol 18) and nonadecaprenol (prenol 19) was two times higher than that using conventional reversed-phase high-performance liquid chromatography. Our SFC technique allows the advantage of baseline separation of polyprenol samples containing hydrophobic components such as terpenes or fatty acids that are unfavorable for good separation. This method is very useful for the analysis of structurally close polyprenol analogues of rubber plant metabolites.

Chromatography, Liquid↗
PubMed2001

Laparascope-assisted versus conventional restorative proctocolectomy with rectal mucosectomy.

To assess the advantages of a laparoscope-assisted proctocolectomy with ileal J-pouch anal anastomosis compared with conventional procedures, we retrospectively analyzed the results of the two procedures as follows: Eleven patients including five patients with familial adenomatous polyposis (FAP) and six with ulcerative colitis (UC) underwent a laparoscope-assisted proctocolectomy and hand-sewn ileal J-pouch anal anastomosis at our department from June 1997 to November 1999. This laparoscope-assisted colectomy (LAC) group was then compared with a group of 13 patients who had undergone conventional ileal pouch anal anastomosis using a standard laparotomy from 1986 to 1997. The median operative time of the LAC group was 8h 23min, which was 81 min longer than that of the standard colectomy (SC) group. The number of days during which eating was prohibited were similar in the two groups but the median postoperative hospital stay was significantly shorter in the LAC group (24.1 days). In the LAC group, the small incisions showed better cosmetic results and there was also a remarkable reduction in the degree of postoperative pain. In conclusion, a laparoscope-assisted proctocolectomy with ileal J-pouch anal anastomosis can be employed widely in patients with FAP and also in selected patients with UC.

Adenomatous Polyposis Coli↗
PubMed2001

The occurrence of geometric polyprenol isomers in the rubber-producing plant, Eucommia ulmoides Oliver.

The chain length and geometric isomerism of polyprenols from Eucommia ulmoides Oliver were analyzed using supercritical fluid chromatography. After intensive effort to establish separation conditions for geometric isomers, a phenyl-bonded silica gel-packed column was found that cleanly separated poly-trans and -cis prenols. The presence of long-chain poly-trans prenols (>9 mers) was confirmed for the first time in plants. Trans isomers were found in the leaf, seed coat, and root, but not in the bark and seed. Poly-trans prenols in this plant may act as intermediates for trans-polyisoprene biosynthesis.

Chromatography, High Pressure Liquid↗
PubMed2001

Consolidation of transient ionotropic glutamate signals through nuclear transcription factors in the brain.

Long-lasting alterations of neuronal functions could involve mechanisms associated with consolidation of transient extracellular signals through modulation of de novo synthesis of particular functional proteins in the brain. In eukaryotes, protein de novo synthesis is mainly under the control at the level of gene transcription by transcription factors in the cell nucleus. Transcription factors are nuclear proteins with an ability to recognize particular core nucleotides at the upstream and/or downstream of target genes, and thereby to modulate the activity of RNA polymerase II that is responsible for the formation of mRNA from double stranded DNA. Gel retardation electrophoresis is widely employed for conventional detection of DNA binding activities of a variety of transcription factors with different protein motifs. Extracellular ionotropic glutamate (Glu) signals lead to rapid and selective potentiation of DNA binding of the nuclear transcription factor activator protein-1 (AP1) that is a homo- and heterodimeric complex between Jun and Fos family members, in addition to inducing expression of the corresponding proteins, in a manner unique to each Glu signal in murine hippocampus. Therefore, extracellular Glu signals may be differentially transduced into the nucleus to express AP1 with different assemblies between Jun and Fos family members, and thereby to modulate de novo synthesis of the individual target proteins at the level of gene transcription in the hippocampus. Such mechanisms may be operative on synaptic plasticity as well as delayed neuronal death through consolidation of alterations of a variety of cellular functions induced by transient extracellular signals in the brain.

Animals↗
PubMed2001

Effects of glutathione depletion by 2-cyclohexen-1-one on excitatory amino acids-induced enhancement of activator protein-1 DNA binding in murine hippocampus.

We have investigated the role of glutathione in mechanisms associated with excitatory amino acid signaling to the nuclear transcription factor activator protein-1 (AP1) in the brain using mice depleted of endogenous glutathione by prior treatment with 2-cyclohexen-1-one (CHX). In the hippocampus of animals treated with CHX 2 h before, a significant increase was seen in enhancement of AP1 DNA binding when determined 2 h after the injection of kainic acid (KA) at low doses. The sensitization to KA was not seen in animals injected with CHX 24 h before, in coincidence with the recovery of glutathione contents to the normal levels. By contrast, CHX did not significantly affect the potentiation by NMDA of AP1 binding under any experimental conditions. Prior treatment with CHX resulted in facilitation of behavioral changes induced by KA without affecting those induced by NMDA. These results suggest that endogenous glutathione may be at least in part involved in molecular mechanisms underlying transcriptional control by KA, but not by NMDA, signals of cellular functions.

Animals↗
PubMed2001

Chemistry of zerumbone. 2. Regulation of ring bond cleavage and unique antibacterial activities of zerumbone derivatives.

Further investigation of the chemistry of the eleven-membered cyclic sesquiterpene, zerumbone, the major component of the wild ginger, Zingiber zerumbet Smith, has revealed a new selective epoxidation process, a further example of a novel Favorskii-initiated double ring contraction, and a regiospecific fragmentation of zerumbone dibromide derivatives. Several zerumbone derivatives were found to be selective inhibitors of the growth of gram-positive bacteria.

Anti-Bacterial Agents↗
PubMed2001

Antibacterial agents that inhibit histidine protein kinase YycG of Bacillus subtilis.

We demonstrated in vitro that YycG-YycF of Bacillus subtilis constitutes a two-component system and shows a specificity of the sensor protein for the cognate phosphorylation partner. Based on inhibition of such an autophosphorylation of YycG, we searched imidazole and zerumbone derivatives to identify the antibacterial agents such as NH125, NH126, NH127, and NH0891.

Anti-Bacterial Agents↗
PubMed2000

Analysis of poly(ethyl methacrylate)s by on-line hyphenation of liquid chromatography at the critical adsorption point and nuclear magnetic resonance spectroscopy

Liquid chromatography at the critical adsorption point (LC CAP) with on-line NMR detection (on-line LC CAP NMR) was utilized for analysis of tacticity distribution of stereo-regular poly(ethyl methacrylate)s (PEMAs). The separation of a model PEMA sample composed of four constituents with similar molar masses (Mw = (14-16) x 10(3) g mol-1) differing in their tacticity (rr triad content = 0, 33, 68, and 89%) was achieved by LC CAP with a mixed eluent composed of acetone, acetone-d6, and cyclohexane. The tacticity composition within each peak eluted from the LC CAP column was directly determined by a 750-MHz 1H NMR spectrometer that was used as a real-time detector in the continuous-flow mode. Tacticity distribution in a particular PEMA sample with mm/mr/rr = 2/45/53 and narrow molar mass distribution of Mw/Mn = 1.05 has been revealed by the LC CAP NMR technique.

Journal Article↗
PubMed2000

Differential expression and phosphorylation of particular fos family members by kainate in nuclear and cytosolic fractions of murine hippocampus.

An i.p. injection of kainate resulted in severe losses of neuronal cells stained by Cresyl Violet in the CA1 and CA3 pyramidal layers of the murine hippocampus within two weeks, without affecting those in the dentate granule layer up to six weeks. Immunohistochemical analysis revealed marked and predominant expression of Fos family members, including c-Fos, Fos-B and Fra-2 proteins, in the dentate granule layer of the hippocampus, but not in the pyramidal layers, 2-18h after administration. Immunoblotting experiments showed that kainate induced more potent expression of c-Fos protein in nuclear fractions obtained 2h after injection than those obtained 18h later, with similar expression between cytosolic fractions obtained 2 and 18h after administration. Both Fos-B and Fra-2 proteins were more potently expressed in nuclear and cytosolic fractions 18h after administration than 2h when determined on immunoblotting analysis. Two-dimensional electrophoresis revealed expression of several proteins immunoreactive to the anti-c-Fos antibody with different isoelectric points in response to kainate in nuclear and cytosolic fractions of the hippocampus for 2-18h after a single injection. Immunoprecipitation analysis using the anti-c-Fos antibody showed phosphorylation of c-Fos protein on serine residues in hippocampal nuclear fractions 2h after administration, with additional phosphorylation on tyrosine residues 18h later. Prior treatment of the protein synthesis inhibitor cycloheximide prevented the expression of immunoreactivities to the anti-c-Fos antibody detected on two-dimensional electrophoresis in hippocampal nuclear fractions obtained 2h after administration.These results suggest that in vivo kainate signals may lead to persistent expression of the transcription factor activator protein-1 that consists of different Fos family members, as well as of c-Fos protein phosphorylated on serine and/or tyrosine residues, at an early stage after administration. Such signal consolidation processes could play a role in mechanisms associated with neuronal survival after kainate in the dentate granular layer of murine hippocampus.

Animals↗
PubMed2000

Identification and characterization of a potent antibacterial agent, NH125 against drug-resistant bacteria.

New imidazole compounds were synthesized to develop a novel and effective antibacterial agent (1-benzyl-3-cetyl-2-methylimidazolium iodide, NH125). In vitro experiments demonstrated that NH125 effectively inhibited a number of different histidine protein kinases. Furthermore, oxacillin-resistant Staphylococcus aureus (ORSA), vancomycin-resistant Enterococcus faecalis (VRE), penicillin-resistant Streptococcus pneumoniae (PRS), and other Gram-positive and Gram-negative bacteria were found to be very sensitive to NH125.

Anti-Bacterial Agents↗