Biomedical subjects

Hideyuki Suzuki

Publications and source records attributed to Hideyuki Suzuki.

At least 37 records · Page 2Linked to original sources

PubMed2006

Neuroendocrine cell differentiation of poorly differentiated colorectal adenocarcinoma correlates with liver metastasis.

Poorly differentiated (PD) adenocarcinoma often retains the capacity for neuroendocrine (NE) cell differ-entiation; however, it is difficult to distinguish the NE cell differentiation by routine hematoxylin and eosin staining. It is important to detect the presence of NE cell differentiation in advanced colorectal carcinomas because these carcinomas have been shown to produce distant metastasis at the time of diagnosis and to have a particularly poor prognosis. In this study, the characteristics of PD adenocarcinoma with NE cell differentiation and its biological metastatic mechanisms were investigated. Forty-eight of 2204 colorectal cancer patients, diagnosed as having PD adenocarcinoma (2.2%) were enrolled in this study. Immunohistochemical analysis was performed with anti-chromogranin A anti-synaptophysin, anti-CD34, anti-D2-40, and anti-VEGF antibodies. The clinicopathological factors for PD adenocarcinoma with NE cell differentiation were compared with those for PD adenocarcinoma without NE cell differentiation. Microvessel density (MVD) was assessed using immunostained slides with anti-CD34 antibody and vascular endothelial growth factor (VEGF) expression in PD adenocarcinoma with NE cell differentiation was confirmed by in situ hybridization. By immunohistochemical staining for chromogranin A and synaptophysin, NE cell differentiation was detected in eight of 48 patients (16.7%) with PD adenocarcinoma. The frequency of liver metastasis at the time of diagnosis was significantly higher in patients having PD adenocarcinoma with NE cell differentiation (p=0.03). Moreover, MVD and VEGF expression level tended to be higher in patients having PD adenocarcinoma with NE cell differentiation (p=0.13 and 0.068, respectively). NE cell differentiation in PD adenocarcinoma may produce liver metastasis through microvessel formation in the tumor induced by VEGF. In PD colorectal adenocarcinoma, immunohistochemical analysis of NE markers is important for establishing the presence of NE cell differentiation and further study is necessary to evaluate the effectiveness of anti-angiogenic drugs to PD adenocarcinoma with NE cell differentiation.

Adenocarcinoma↗

PubMed2005

12-oxo-phytodienoic acid triggers expression of a distinct set of genes and plays a role in wound-induced gene expression in Arabidopsis.

Jasmonic acid (JA) and methyl jasmonate (MeJA), collectively known as JAs, regulate diverse physiological processes in plants, including the response to wounding. Recent reports suggest that a cyclopentenone precursor of JA, 12-oxo-phytodienoic acid (OPDA), can also induce gene expression. However, little is known about the physiological significance of OPDA-dependent gene expression. We used microarray analysis of approximately 21,500 Arabidopsis (Arabidopsis thaliana) genes to compare responses to JA, MeJA, and OPDA treatment. Although many genes responded identically to both OPDA and JAs, we identified a set of genes (OPDA-specific response genes [ORGs]) that specifically responded to OPDA but not to JAs. ORGs primarily encoded signaling components, transcription factors, and stress response-related genes. One-half of the ORGs were induced by wounding. Analysis using mutants deficient in the biosynthesis of JAs revealed that OPDA functions as a signaling molecule in the wounding response. Unlike signaling via JAs, OPDA signaling was CORONATINE INSENSITIVE 1 independent. These results indicate that an OPDA signaling pathway functions independently of JA/MeJA signaling and is required for the wounding response in Arabidopsis.

Acrolein↗

PubMed2005

Elucidation of gene-to-gene and metabolite-to-gene networks in arabidopsis by integration of metabolomics and transcriptomics.

Since the completion of genome sequences of model organisms, functional identification of unknown genes has become a principal challenge in biology. Post-genomics sciences such as transcriptomics, proteomics, and metabolomics are expected to discover gene functions. This report outlines the elucidation of gene-to-gene and metabolite-to-gene networks via integration of metabolomics with transcriptomics and presents a strategy for the identification of novel gene functions. Metabolomics and transcriptomics data of Arabidopsis grown under sulfur deficiency were combined and analyzed by batch-learning self-organizing mapping. A group of metabolites/genes regulated by the same mechanism clustered together. The metabolism of glucosinolates was shown to be coordinately regulated. Three uncharacterized putative sulfotransferase genes clustering together with known glucosinolate biosynthesis genes were candidates for involvement in biosynthesis. In vitro enzymatic assays of the recombinant gene products confirmed their functions as desulfoglucosinolate sulfotransferases. Several genes involved in sulfur assimilation clustered with O-acetylserine, which is considered a positive regulator of these genes. The genes involved in anthocyanin biosynthesis clustered with the gene encoding a transcriptional factor that up-regulates specifically anthocyanin biosynthesis genes. These results suggested that regulatory metabolites and transcriptional factor genes can be identified by this approach, based on the assumption that they cluster with the downstream genes they regulate. This strategy is applicable not only to plant but also to other organisms for functional elucidation of unknown genes.

Arabidopsis↗

PubMed2005

Effective production of 3,4-dihydroxyphenyl-L-alanine (L-DOPA) with Erwinia herbicola cells carrying a mutant transcriptional regulator TyrR.

The enzymatic production of 3,4-dihydroxyphenyl-L-alanine (L-DOPA) using Erwinia herbicola cells involves the action of tyrosine phenol-lyase (Tpl, EC 4.1.99.2). Since Tpl is only synthesized under L-tyrosine-induced conditions, the addition of L-tyrosine to the medium is unavoidable when preparing cells (the enzyme source), but severely impedes the pure preparation of the final product L-DOPA. We circumvented this problem by using recombinant E. herbicola cells carrying a mutant transcriptional regulator TyrR, which is capable of activating the tpl promoter in the absence of L-tyrosine.

Erwinia↗

PubMed2005

Molecular characterization of a novel quinolizidine alkaloid O-tigloyltransferase: cDNA cloning, catalytic activity of recombinant protein and expression analysis in Lupinus plants.

A novel acyltransferase committed to the final step of quinolizidine alkaloid biosynthesis, tigloyl-CoA:(-)-13alpha-hydroxymultiflorine/(+)-13alpha-hydroxylupanine O-tigloyltransferase, has been purified from Lupinus albus. The internal amino acid sequences were determined with protease-digested fragments of 25 and 30 kDa bands, allowing design of primers for amplification of cDNA fragments by polymerase chain reaction. Using an amplified fragment as the probe, a full-length cDNA clone was isolated. Sequence analysis revealed that the cDNA encodes a protein of 453 amino acids with a molecular mass of 51.2 kDa. Phylogenetic analysis of the deduced amino acid sequences indicated that this alkaloid acyltransferase belongs to a unique subfamily of a plant acyl-CoA-dependent acyltransferase gene family. The cDNA was expressed in bacterial cells as a recombinant protein fused to glutathione S-transferase. The fusion protein was affinity purified and cleaved to yield the recombinant enzyme for the study of catalytic properties. The recombinant enzyme catalyzed the acyltransfer reaction from tigloyl-CoA to (-)-13alpha-hydroxymultiflorine and (+)-13alpha-hydroxylupanine. Benzoyl-CoA could also serve efficiently as an acyl donor for these hydroxylated alkaloids. RNA blot analysis suggested that the gene was expressed in roots and hypocotyls but not in cotyledons and leaves. These results indicated that this specialized acyltransferase, isolated for the first time as tigloyltransferase from nature, is committed to control the quinolizidine alkaloid patterns in a tissue-specific manner.

Acyltransferases↗

PubMed2005

Construction of an effective protein expression system using the tpl promoter in Escherichia coli.

An effective protein expression system was constructed in Escherichia coli using the promoter of the tyrosine phenol-lyase (tpl) gene of Erwinia herbicola. This system involves a mutant form of the TyrR protein with an enhanced ability to activate tpl and the TutB protein with an ability to transport L-tyrosine (an inducer of Tpl). The highest expression level obtained for this system was more than twice that obtained for the tac system, although it was lower than the level obtained for the T7 system, as revealed with the lac-reporter assay and SDS-polyacrylamide gel electrophoresis.

Amino Acid Transport Systems, Neutral↗

PubMed2005

Dehydroepiandrosterone modulates toll-like receptor expression on splenic macrophages of mice after severe polymicrobial sepsis.

Toll-like receptors (TLRs) play a pivotal role in the induction of innate immunity after the transactivation of proinflammatory cytokine genes. However, the responses of TLRs during severe polymicrobial sepsis have not been thoroughly examined. Although dehydroepiandrosterone (DHEA), a steroid hormone, is reported to have an immunomodulatory effect after sepsis, the mechanism responsible for its salutary is not known. To investigate this, male ICR/Jcl mice (5-8 weeks old) were subjected to sepsis by cecal ligation and puncture (CLP) or sham operation. The mice received vehicle or DHEA (40 mg/kg body weight) subcutaneously immediately after the surgery. Plasma IL-10 levels and splenic macrophage TNF-alpha production, as well as the expression levels of CD14, TLR2, and TLR4 mRNAs on splenic macrophages, were assessed 6 h after the surgery. The results indicate that mice with sepsis show a marked increase in the plasma IL-10 levels and a decrease in TNF-alpha production by splenic macrophages. TLR2 and TLR4 mRNA expression levels after CLP were significantly lower compared with those after the sham operation. TNF-alpha production and TLR2 and TLR4 mRNA expression on splenic macrophages are restored with DHEA administration. Furthermore, administration of DHEA after CLP delayed the mortality of animals. These results indicate that the anti-inflammatory phase of sepsis induces a marked down-regulation of TLR expression on splenic macrophages; however, administration of DHEA resulted in the restoration of TLR2 and TLR4 mRNA expression.

Adjuvants, Immunologic↗

PubMed2005

KaPPA-view: a web-based analysis tool for integration of transcript and metabolite data on plant metabolic pathway maps.

The application of DNA array technology and chromatographic separation techniques coupled with mass spectrometry to transcriptomic and metabolomic analyses in plants has resulted in the generation of considerable quantitative data related to transcription and metabolism. The integration of "omic" data is one of the major concerns associated with research into identifying gene function. Thus, we developed a Web-based tool, KaPPA-View, for representing quantitative data for individual transcripts and/or metabolites on plant metabolic pathway maps. We prepared a set of comprehensive metabolic pathway maps for Arabidopsis (Arabidopsis thaliana) and depicted these graphically in Scalable Vector Graphics format. Individual transcripts assigned to a reaction are represented symbolically together with the symbols of the reaction and metabolites on metabolic pathway maps. Using quantitative values for transcripts and/or metabolites submitted by the user as Comma Separated Value-formatted text through the Internet, the KaPPA-View server inserts colored symbols corresponding to a defined metabolic process at that site on the maps and returns them to the user's browser. The server also provides information on transcripts and metabolites in pop-up windows. To demonstrate the process, we describe the dataset obtained for transgenic plants that overexpress the PAP1 gene encoding a MYB transcription factor on metabolic pathway maps. The presentation of data in this manner is useful for viewing metabolic data in a way that facilitates the discussion of gene function.

Computational Biology↗

PubMed2005

Coordinated activation of metabolic pathways for antioxidants and defence compounds by jasmonates and their roles in stress tolerance in Arabidopsis.

Jasmonic acid (JA) and methyl jasmonate (MeJA), collectively termed jasmonates, are ubiquitous plant signalling compounds. Several types of stress conditions, such as wounding and pathogen infection, cause endogenous JA accumulation and the expression of jasmonate-responsive genes. Although jasmonates are important signalling components for the stress response in plants, the mechanism by which jasmonate signalling contributes to stress tolerance has not been clearly defined. A comprehensive analysis of jasmonate-regulated metabolic pathways in Arabidopsis was performed using cDNA macroarrays containing 13516 expressed sequence tags (ESTs) covering 8384 loci. The results showed that jasmonates activate the coordinated gene expression of factors involved in nine metabolic pathways belonging to two functionally related groups: (i) ascorbate and glutathione metabolic pathways, which are important in defence responses to oxidative stress, and (ii) biosynthesis of indole glucosinolate, which is a defence compound occurring in the Brassicaceae family. We confirmed that JA induces the accumulation of ascorbate, glutathione and cysteine and increases the activity of dehydroascorbate reductase, an enzyme in the ascorbate recycling pathway. These antioxidant metabolic pathways are known to be activated under oxidative stress conditions. Ozone (O3) exposure, a representative oxidative stress, is known to cause activation of antioxidant metabolism. We showed that O3 exposure caused the induction of several genes involved in antioxidant metabolism in the wild type. However, in jasmonate-deficient Arabidopsis 12-oxophytodienoate reductase 3 (opr3) mutants, the induction of antioxidant genes was abolished. Compared with the wild type, opr3 mutants were more sensitive to O3 exposure. These results suggest that the coordinated activation of the metabolic pathways mediated by jasmonates provides resistance to environmental stresses.

Acetates↗

PubMed2005

The yliA, -B, -C, and -D genes of Escherichia coli K-12 encode a novel glutathione importer with an ATP-binding cassette.

Glutathione protects cells and organisms from oxygen species and peroxides and is indispensable for aerobically living organisms. Moreover, it acts against xenobiotics and drugs by the formation and excretion of glutathione S conjugates. In this study, we show that the yliA, -B, -C, and -D genes of Escherichia coli K-12 encode a glutathione transporter with the ATP-binding cassette. The transporter imports extracellular glutathione into the cytoplasm in an ATP-dependent manner. This transporter, along with gamma-glutamyltranspeptidase, has an important role in E. coli growth with glutathione as a sole sulfur source.

ATP-Binding Cassette Transporters↗

PubMed2005

Are sterile water and brushes necessary for hand washing before surgery in Japan?

PURPOSE: To examine whether sterile water and brushes are necessary for hand washing before surgery. METHOD: Twenty-two operating room nurses were randomly divided into two groups as follows: 11 nurses who used 7.5% povidone iodine (PVI group) and another 11 nurses who used 4% chlorhexidine gluconate (CHG group) to wash their hands using the rubbing method. All the nurses were examined for bacterial contamination of their hands before and after surgical hand rubbing. We used tap water to wash the hands at the sink used for washing surgical instruments in the operating room and non sterilized plastic brushes. RESULTS: No bacteria were detected in the tap water. Before washing the hands, the number of bacteria detected was 5.0 x 10(3) cfu/H in the PVI group and 4.0 x 10(3) cfu/H in the CHG group, which were similar in both groups. After washing the hands, the median value of the bacteria decreased to 8.7 x 10(2) cfu/H in the PVI group and 0 cfu/H in the CHG group. CONCLUSIONS: Sterile water and brushes are not necessary for preoperative scrubbing up. When using tap water for surgical hand washing, 1) the hand-rubbing method should be used; 2) a quick-alcohol-based disinfectant scrub should be used; 3) the concentration of free chloride in the water should be maintained at over 0.1 PPM; 4) the bacterial contamination of the water should be checked; and 5) the faucet should be routinely cleaned and sterilized.

Anti-Infective Agents, Local↗

PubMed2005

Abdominal incisional hernia repair using the Composix Kugel Patch: two case reports.

We describe two patients with abdominal incisional hernias, which occurred after appendectomy and replacement of an artificial blood vessel. Both were treated by operative hernial repair with the Composix Kugel Patch (C.R. Bard Inc.), a composite mesh that combines polypropylene mesh and expanded polytetrafluoroethylene (Gore-Tex). The mesh has various beneficial characteristics. It is a reinforcing material for the abdominal wall; even when in direct contact with the intestinal tract it is minimally adherent to the intestinal tract. The mesh expands readily and is easily fixed to the abdominal wall because it has a shape-memory ring. The long-term results of operative repair with this mesh have not yet been reported, but it is hoped that the aforementioned characteristics will yield favorable outcomes.

Aged↗

PubMed2005

The role of transanal endoscopic microsurgery for rectal tumors.

PURPOSE: The management of rectal tumors is complex, because of the balance between preserving rectoanal function and curing the patient. Transanal endoscopic microsurgery (TEM) is both an effective treatment for benign rectal tumors and early cancers, and a diagnostic tool for determining tumor depth, or for residual tumors of post endoscopic mucosal resection. In the present study, we evaluated the role of TEM in the management of rectal tumors. METHODS: Twenty-six patients with rectal tumors underwent TEM from December 2000 through March 2005 in our department. The operations were performed by a single surgeon, and the indications were mainly limited to a) benign tumors for which endoscopic resection was difficult, b) early cancers that had invaded the submucosa within 500 microm of the muscularis mucosae, c) submucosal tumors, i.e., gastrointestinal stromal tumor, carcinoid tumors, d) local excision for diagnosis, and e) palliative resection for high-risk cases. Anesthesia, operation time, sizes of the tumor and of resected specimens, postoperative complications, length of hospitalization, pathological results, and postoperative recurrence rate were reviewed. RESULTS: The mean age of patients was 61.9 years, and the cases included 14 rectal cancers, 7 adenomas, 1 gastrointestinal stromal tumor, and 3 rectal carcinoid tumors. The mean operation time was 96 min (range, 40 approximately 235 min.). The average postoperative hospital stay was 4.8 days. All tumors were resected with horizontal and vertical safety margin. The mean size of the resected specimens was 9.0 cm(2). In one case, the tumor had infiltrated the proper muscle layer, as shown by intraoperative frozen sectioning, which necessitated abdominoperineal resection. In 3 cases, pathological examination revealed massive infiltration into the submucosal layer. 2 patients underwent low anterior resection, and the remaining patient refused additional surgery despite our recommendation. No deaths occurred. No major postoperative complications were noted. The mean follow-up period was 27.2 months. Only one case of lymph node metastasis was observed, in the left iliac lymph node 3 years after TEM. CONCLUSIONS: TEM is a minimally invasive surgical procedure for rectal tumors, which allows the whole depth of the rectal wall to be resected with a safety surgical margin. Although TEM requires technical skill and accurate preoperative diagnosis, the procedure is safe, facilitates accurate diagnosis of tumor depth, and limits the need for additional surgery.

Adult↗

PubMed2004

Methyl jasmonate and yeast elicitor induce differential transcriptional and metabolic re-programming in cell suspension cultures of the model legume Medicago truncatula.

Exposure of cell suspension cultures of Medicago truncatula Gaerth. to methyl jasmonate (MeJA) resulted in up to 50-fold induction of transcripts encoding the key triterpene biosynthetic enzyme beta-amyrin synthase (betaAS; EC 5.4.99.-). Transcripts reached maximum levels at 24 h post-elicitation with 0.5 mM MeJA. The entry point enzymes into the phenylpropanoid and flavonoid pathways, L: -phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) and chalcone synthase (CHS; EC 2.3.1.74), respectively, were not induced by MeJA. In contrast, exposure of cells to yeast elicitor (YE) resulted in up to 45- and 14-fold induction of PAL and CHS transcripts, respectively, at only 2 h post-elicitation. betaAS transcripts were weakly induced at 12 h after exposure to YE. Over 30 different triterpene saponins were identified in the cultures, many of which were strongly induced by MeJA, but not by YE. In contrast, cinnamic acids, benzoic acids and isoflavone-derived compounds accumulated following exposure of cultures to YE, but few changes in phenylpropanoid levels were observed in response to MeJA. DNA microarray analysis confirmed the strong differential transcriptional re-programming of the cell cultures for multiple genes in the phenylpropanoid and triterpene pathways in response to MeJA and YE, and indicated different responses of individual members of gene families. This work establishes Medicago cell cultures as an excellent model for future genomics approaches to understand the regulation of legume secondary metabolism.

Abscisic Acid↗

PubMed2004

A novel putrescine utilization pathway involves gamma-glutamylated intermediates of Escherichia coli K-12.

A novel bacterial putrescine utilization pathway was discovered. Seven genes, the functions of whose products were not known, are involved in this novel pathway. Five of them encode enzymes that catabolize putrescine; one encodes a putrescine importer, and the other encodes a transcriptional regulator. This novel pathway involves six sequential steps as follows: 1) import of putrescine; 2) ATP-dependent gamma-glutamylation of putrescine; 3) oxidization of gamma-glutamylputrescine; 4) dehydrogenation of gamma-glutamyl-gamma-aminobutyraldehyde; 5) hydrolysis of the gamma-glutamyl linkage of gamma-glutamyl-gamma-aminobutyrate; and 6) transamination of gamma-aminobutyrate to form the final product of this pathway, succinate semialdehyde, which is the precursor of succinate.

Adenosine Triphosphate↗

PubMed2004

Development of an efficient enzymatic production of gamma-D-glutamyl-L-tryptophan (SCV-07), a prospective medicine for tuberculosis, with bacterial gamma-glutamyltranspeptidase.

Gamma-D-Glutamyl-L-tryptophan (SCV-07) is a prospective medicine for the treatment of tuberculosis, according to the phase two clinical trial. Because gamma-D-glutamyl-L-tryptophan has several reactive groups in its molecule, consists of D- and L-amino acids, and is connected by gamma-glutamyl linkage, its chemical synthesis is complicated. An efficient enzymatic method to synthesize gamma-D-glutamyl-L-tryptophan from D-glutamine and L-tryptophan employing bacterial gamma-glutamyltranspeptidase was developed. The optimum reaction conditions were 50 mM D-glutamine, 50 mM L-tryptophan, and 0.2 U ml(-1) gamma-glutamyltranspeptidase, pH 9-9.5, and incubation at 37 degrees C for 5 h. After a 5 h incubation, 33 mM gamma-D-glutamyl-L-tryptophan was obtained, the conversion rate being 66%. The product was purified by Dowex 1 x 8 column and was considered to be gamma-D-glutamyl-L-tryptophan.

Dipeptides↗

PubMed2004

The LIV-I/LS system as a determinant of azaserine sensitivity of Escherichia coli K-12.

The growth of Escherichia coli is inhibited by an antibiotic compound, azaserine (O-diazoacetyl-L-serine). Previous studies revealed the biochemical properties of azaserine, which involves inhibition of various enzymatic reactions as well as introduction of DNA breakage. However, genetically, nothing has been elucidated except that all the azaserine-resistant strains isolated so far carry lesions in the aroP gene as a primary determinant. Here, we demonstrate that, in addition to AroP, the LIV-I/LS system, an ATP-binding cassette type transporter, is involved in azaserine sensitivity of E. coli, by genetic analysis and transport studies, in which Ki value for azaserine was determined to be approximately 10(-3) M.

Amino Acid Transport Systems↗

PubMed2004

Enzymatic synthesis of gamma-glutamylvaline to improve the bitter taste of valine.

The taste of several bitter amino acids is reduced, sourness produced, and preference increased by gamma-glutamylization. An enzymatic method for synthesizing gamma-Glu-Val involving bacterial gamma-glutamyltranspeptidase (GGT) was developed. The optimum reaction conditions for the synthesis of gamma-Glu-Val were 20 mM Gln, 300 mM Val, and 0.04 U/ml GGT, pH 10. After 3-hr incubation at 37 degrees C, 17.6 mM gamma-Glu-Val was obtained, with the yield being 88%. gamma-Glu-Val was purified on a Dowex 1 x 8 column and then identified by NMR.

Dipeptides↗