Biomedical subjects

A Tanaka

Publications and source records attributed to A Tanaka.

At least 109 records · Page 6Linked to original sources

PubMed2001

Efficacy and safety of PTCA using brachial approach and low-dose heparin.

Percutaneous transluminal coronary angioplasty (PTCA) is routinely performed using the femoral approach. However, recent reports suggest the usefulness of the brachial approaches for patients for whom the femoral approach is impossible due to peripheral vessel disease or to shortened postoperative rest times. However, some reports have revealed that the incidence of vascular complications undergoing brachial-approach PTCA may be higher than those with the femoral approach, possibly due to relatively higher dose of heparin. Accordingly, in this study we evaluated the efficacy and safety of PTCA using the brachial approach and low-dose heparin, hypothesizing that lowering the heparin dose might result in reduced vascular complications. The study population of patients admitted for angina pectoris consisted of 217 subjects (221 lesions) who underwent brachial-approach PTCA and 102 subjects (115 lesions) who underwent PTCA via the femoral approach. Both groups were monitored for complications. There were no significant differences in patient or lesion characteristics between the groups. Incidence of vascular complications tended to be lower in the brachial group than in the femoral group (1.8% vs. 3.5%), although the difference did not reach statistical significance. Use of anodynes was also significantly lower in the brachial group (3.6% vs. 33%). PTCA from the brachial approach with low-dose heparin is as safe and effective a strategy as compared with the femoral approach with standard dose of heparin.

Aged↗

PubMed2001

Purification of activins from androgen-independent Shionogi carcinoma cells demonstrates enhanced expression of activin betaB-subunit under androgen-depleted cell conditions in vitro and in vivo.

Here, we report characterization of growth factors secreted from androgen-independent mouse mammary Shionogi carcinoma cells. Previous isolation of fibroblast growth factor 8 (FGF8) from androgen-dependent Shionogi carcinoma SC-3 cells prompted us to characterize growth factors secreted from the androgen-independent cells. After several purification procedures, mitogens for NIH3T3 cells from the androgen-independent cells were identified as activins on the grounds that activin betaA- and betaB-subunits are detected in the active fractions by Western blotting and that the growth-promoting effects by the active fractions are specifically inhibited in the presence of follistatin. In addition, exogenous activins, but not inhibin, stimulated the growth of NIH3T3 cells in a dose-dependent manner. Interestingly, transcripts of activin betaB-subunit were predominantly found in the androgen-independent cells while its betaA-subunit was universally expressed in both androgen-dependent and -independent Shionogi carcinoma cells. In concordant with this in vitro finding, transcripts of activin betaB-subunit were enhanced in murine prostates after castration. Therefore, expression of activin betaB-subunit, but not its betaA-subunit, is likely to be related with androgen-depleted cell conditions in prostates, and possibly in androgen-related cancers.

3T3 Cells↗

PubMed2001

Observations on the effects of caged carp culture on water and sediment metal concentrations in lake Kasumigaura, Japan.

The concentrations of 24 elements in the sediment and associated water column were monitored at two sites, one an area of intensive cage culture of carp, the other a wild site far from known cage culture areas, in Lake Kasumigaura, Japan, between September 1994 and September 1995. The concentrations of most elements in Lake Kasumigaura are mostly sub-parts per billion, except those for Ca, Fe, K, Mg, Na, P, and Si. The concentrations of Cd, Co, Cu, Mn, Ni, Pb, V, and Fe in Lake Kasumigaura are higher than the values in Lake Mashu, Lake Shikotsu, and Lake Biwa, and comparable to the levels in open ocean. Statistically significant differences in metal concentrations were observed between the culture and wild sites, with metal concentrations consistently higher at the culture site. Although cage culture of carp in the Lake Kasumigaura system may be causing localized increase in metal concentrations in the sediments, we must treat the results with caution, since the concentrations of metals observed in the sediments in 1995 were lower than those observed in 1979 for all metals at both sampling sites. In conclusion, further study of the concentrations of metals in the lake as a whole must be undertaken before the differences between the culture and wild sites can be proved, or disproved, to be the result of carp culture.

Animals↗

PubMed2001

Genomic analysis of differentially expressed genes in liver and biliary epithelial cells of patients with primary biliary cirrhosis.

The characterization of differentially expressed genes provides a powerful tool for identifying molecules that may be involved in the pathogenesis of disease. We have used two independent techniques to identify overexpressed transcripts in bile duct cells and in liver from patients with primary biliary cirrhosis (PBC). In the first method, we used suppressive subtractive hybridization to compare mRNA from isolated PBC bile duct epithelial cells (BECs) to normal BECs and identified 71 clones as transcribed at higher levels in PBC-BECs. Amongst these clones, 62/71 had matches in a non-redundant nucleotide database and 9/71 had matches in an EST database. Of the 62 clones, 51/62 include a complexity of genes involved in cell proliferation, signal transduction, transcription regulation, RNA processing, carbohydrate metabolism and hypothetical/unknown proteins; 4/62 were identified as interstitial collagenase and collagenase precursors, 4/62 as ribosomal proteins, 3/62 as mitochondrial DNA. The mitochondrial cDNA sequences included cytochrome c oxidase, Wnt-13, and the pHL gene, a c-myc oncogene containing coxIII sequence. In the second method, we constructed cDNA libraries from three different PBC livers and sequenced a total of 12,324 independent clones. These 12,324 clones underwent virtual subtraction with 2,814,148 independent clones from Incyte LifeSeq libraries. Twenty one sequences were identified as unique to PBC liver. Collectively, these approaches identified a number of genes involved in signalling, RNA processing, mitochondrial function, inflammation, and fibrosis. Interestingly, both Wnt-13 and Notch transcripts are overexpressed in PBC liver. Further studies are needed to focus on the significance of these genes during the natural history of disease.

Bile Ducts↗

PubMed2001

Single nucleotide polymorphisms of the mannose-binding lectin are associated with susceptibility to primary biliary cirrhosis.

Although the immunopathogenesis of primary biliary cirrhosis (PBC) remains unknown, familial clustering of patients with PBC suggests an important role for genetic factors. In addition, recent data support the thesis that the mucosal immune response against intraluminal pathogens may be involved with the onset of PBC. Mannose-binding lectin (MBL) is a key factor in innate mucosal defenses and has several key single nucleotide polymorphisms (SNPs). To study whether MBL gene SNPs are associated with susceptibility to PBC, we studied 65 patients with PBC and 218 controls by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequence specific priming-polymerase chain reaction (SSP-PCR) to examine four polymorphic loci: two (H/L and X/Y) within the promoter region and the other two (P/Q and A/B) within exon-1. We also analyzed serum MBL concentrations. Interestingly, the prevalence of haplotype HYPA, leading to hyper-production of MBL, as well as HYPA/HYPA genotype were significantly increased in PBC compared to controls (0.53 vs. 0.44, P=0.031; 33.9%vs. 17.0%, P=0.003, respectively). Furthermore, individuals homozygous for HYPA had a significantly increased risk for PBC (odds ratio (OR)=2.51, 95% confidence interval (CI)=1.34-4.66). Our results demonstrate that the MBL genotype can be significantly associated with increased risk for PBC, and further, that increased production of MBL plays a critical role in immunopathogenesis.

Carrier Proteins↗

PubMed2001

The difference in E-cadherin expression between nonvascularized and vascularized nerve grafts: study in the rat sciatic nerve model.

BACKGROUND: We investigated the expression of E-cadherin during nerve regeneration after nonvascularized and vascularized nerve grafts. MATERIALS AND METHODS: We used the rat sciatic nerve model. E-cadherin expression was detected by Western blot analysis and immunofluorescent staining with anti E-cadherin monoclonal antibody. The level of E-cadherin expression was calculated as the amount relative to that of E-cadherin expression of normal control nerve. Furthermore, repair of the neural tissue structure was examined by toluidine blue staining. RESULTS: In both cases, the level of E-cadherin expression decreased at first, and then gradually increased. The maximum level was 1.61 +/- 0.066-fold in the nonvascularized nerve graft and 2.254 +/- 0.071-fold in the vascularized nerve graft. From the 1st to the 16th postoperative weeks, the level of E-cadherin expression in the vascularized nerve graft was significantly higher than that in the nonvascularized nerve graft. In the immunofluorescent staining, E-cadherin expression was almost negative or decreased immediately after the operation, but the degree of expression was gradually increased in Schwann cells. The degree of E-cadherin expression in the vascularized nerve graft was greater than that in the nonvascularized nerve graft. In toluidine blue staining, the velocity of tissue repair was more rapid in the vascularized nerve graft than in the nonvascularized graft. CONCLUSION: These results demonstrate that the E-cadherin expression of grafted nerve was increased during the nerve regeneration, and the expression was mainly observed in Schwann cells. Because the level of E-cadherin expression was significantly higher in the vascularized nerve graft than in the nonvascularized nerve graft, the level of E-cadherin expression may affect the rapidity of nerve regeneration.

Animals↗

PubMed2001

Performance assessment of O-18 water purifier.

In the synthesis of 18F-FDG by the nucleophilic substitution method, 18O-H2O is usually used as target water. The target water should be recovered after synthesis and reused, because it is expensive, but recovered water contains impurities such as organic substances, and it must be purified before reuse. For this reason Sumitomo Heavy Industries, Ltd. developed an O-18 water purifier for elimination of organic substances in recovered water. This instrument consists of a UV irradiation unit and low-temperature distillation unit. Our institution had an opportunity to test use this instrument and evaluated its performance. The concentrations of organic substances after UV irradiation was greatly reduced, and recovery efficiency after distillation by the low-temperature distillation unit was very satisfactory at 99.3 +/- 0.5%. Furthermore, the yield of 18F-FDG from 18O-H20 purified with this instrument was sufficient for the clinical use.

Fluorodeoxyglucose F18↗

PubMed2001

Effect of acute elevation of IGF-I on circulating GH, TSH, insulin, IGF-II and IGFBP-3 levels in non-endocrine short stature (NESS).

It is not clear whether acute and slight elevation of serum IGF-I, which does not affect blood glucose levels, modulates circulating GH levels. To clarify this, small doses of recombinant human IGF-I (rhIGF-I, 5 microg/kg, i.v.) were administered as a bolus to 10 children with non-endocrine short stature (NESS) (5 males and 5 females, 11.2+/-0.7 yr old) after an overnight fast. Physiological saline was administered intravenously to sex- and age-matched NESS controls (5 males and 5 females, 10.9+/-0.7 yr old). The changes of serum GH, TSH, PRL, IGF-I, IGF-II, IGFBP-3, T4, T3 and plasma glucose levels after the administration were compared to those of the control subjects. Serum IGF-I levels increased significantly from 15 to 150 min after injection compared to those in the control group. The peak value was observed at 15 min (delta increment, 74.6+/-11.8 microg/l). At 15 min after the injection, serum insulin was suppressed significantly (p<0.05), although plasma glucose levels were not modified significantly. Serum TSH showed a significant decrease by rhIGF-I at 15 min and 60 min, whereas serum T4 and T3 levels were not modified. Serum GH was also significantly suppressed at 60 min (p<0.02) and showed a rebound increase at 120 min (p<0.05). Serum IGFBP-3 levels after rhIGF-I were higher than controls at 90 min and 150 min. No significant changes of serum PRL, IGF-II, (IGF-I plus IGF-II)/IGFBP-3 ratios were observed after the IGF-I injection compared to controls. These results indicate that circulating IGF-I is a physiological regulator of GH secretion in normal children, since the changes of IGF-I after the small doses of rhlGF-I administration were within physiological ranges and did not affect plasma glucose levels.

Adolescent↗

PubMed2001

Novel and convenient methods for Candida tropicalis gene disruption using a mutated hygromycin B resistance gene.

We established a novel and convenient method to construct a ura3 strain (ura3/ura3) of the asporogenous and diploid yeast, Candida tropicalis, that produces dicarboxylic acid. One copy of the URA3 gene was disrupted using a mutated hygromycin B resistance gene (HYG#). The obtained hygromycin-resistant strain was further transformed with a URA3 disruption cassette and selected on a plate containing 5-fluoroorotic acid. The obtained strains were analyzed and the disruption of the gene was confirmed by PCR and Southern blot analysis. The results showed that the strains were obtained in which allelic URA3 genes were simultaneously disrupted. Furthermore, we established a cotransformation method for this gene disruption, using HYG# in C. tropicalis. In order to disrupt the allelic POX4 genes (encoding acyl-CoA oxidase) of dicarboxylic acid-producing strains, the ARS plasmid (which contained HYG#) and a POX4 disruption cassette (which carried the LAC4 gene encoding beta-galactosidase of Kluyveromyces lactis) were simultaneously introduced by transformation. As a result, the allelic POX4 gene was successfully disrupted.

Anti-Bacterial Agents↗

PubMed2001

Role of electronegativity in the qualitative inference of the TOF-SIMS fragment pattern of inorganic compounds.

The role of the electronegativity of atoms in inorganic compounds in TOF-SIMS fragmentation is discussed. From a study of approximately 30 inorganic compounds--chlorides, oxides, nitrates, and sulfates--a simple rule has been proposed for the dependence of fragment pattern appearance on the electronegativity (electron affinity), which can be easily obtained from handbooks, and the valence of positive and negative ions in these compounds. TOF-SIMS measurements of metal and alloy surfaces, should be corrected for the ionization potentials and/or electronegativities of atoms present in surface contaminants.

Journal Article↗

PubMed2001

Intelligent yeast strains with the ability to self-monitor the concentrations of intra- and extracellular phosphate or ammonium ion by emission of fluorescence from the cell surface.

Saccharomyces cerevisiae strains that respond to environmental changes and transmit the information by emission of fluorescence from the cell surface were constructed. The technique of cell surface engineering enabled the yeast cells to display enhanced cyan blue fluorescent protein (ECFP) or enhanced yellow fluorescent protein (EYFP) on the surface under the control of promoters that sense environmental changes. Two model promoters were examined in this study. For monitoring the intra- and extracellular concentrations of phosphate ion, the PHO5 promoter was chosen to display ECFP. The MEP2 promoter was used to display EYFP to sense the concentrations of ammonium ion. Fluorescence was observed by fluorescence microscopy and immunofluorescence microscopy, and the intensity was measured by a flow cytometer. The relationship between ion concentration inside and outside the cells was evaluated by the change in the rate of fluorescence. This S. cerevisiae system enables environmental changes to be transmitted as intra- and extracellular information using a suitable promoter functioning at real time and in a non-invasive manner.

Bacterial Proteins↗

PubMed2001

Long-term repeated biodesulfurization by immobilized Rhodococcus erythropolis KA2-5-1 cells.

In this study, biodesulfurization (BDS) was carried out using immobilized Rhodococcus erythropolis KA2-5-1 in n-tetradecane containing dibenzothiophene (DBT) as a model oil (n-tetradecane/immobilized cell biphasic system). The cells were immobilized by entrapping them with calcium alginate, agar, photo-crosslinkable resin prepolymers (ENT-4000 and ENTP-4000), and urethane prepolymers (PU-3 and PU-6); and it was found that ENT-4000-immobilized cells had the highest DBT desulfurization activity in the model oil system without leakage of cells from the support. Furthermore, ENT4000-immobilized cells could catalyze BDS repeatedly in this system for more than 900 h with reactivation; and recovery of both the biocatalyst and the desulfurized model oil was easy. This study would give a solution to the problems in BDS, such as the troublesome process of recovering desulfurized oil and the short life of BDS biocatalysts.

Agar↗

PubMed2001

Preparation of an organic solvent-tolerant strain from baker's yeast.

By using immobilized baker's yeast repeatedly in isooctane with occasional reactivation by cultivation, we succeeded in the preparation of an organic solvent-tolerant strain, named KK21, which could grow in the presence of isooctane. This is the first report on an organic solvent-tolerant strain from baker's yeast. Strain KK21 showed high tolerance to organic solvents and maintained a high and stable activity on continuous reduction of n-butyl 3-oxobutanoate in an isooctane-medium two-phase system. Although the morphology of strain KK21 was the same as that of baker's yeast, the saturated fatty acid occupancy (SFA occupancy), which is defined as the percentage of saturated fatty acids in the total fatty acids of phospholipids, of strain KK21 was significantly higher than that of parental baker's yeast when strain KK21 was grown in the presence of isooctane, suggesting that a decrease in fluidity of the cell membrane might play an important role in the tolerance to organic solvents.

Adaptation, Physiological↗

PubMed2001

Function of the prosequence for in vivo folding and secretion of active Rhizopus oryzae lipase in Saccharomyces cerevisiae.

The role of the prosequence of Rhizopus oryzae lipase (ROL) with a preprosequence was analyzed by an expression system using Saccharomyces cerevisiae. When the mature portion of ROL (mROL) fused to the pre-alpha-factor leader sequence was expressed, secretion of active mROL was not observed. However, when mROL was synthesized together with the prosequence in trans (individually and coincidentally), secretion of active mROL was observed. The results indicate that the prosequence of ROL helped correct folding of mROL and its subsequent secretion from the yeast cells, and that physical linkage (cis) of the prosequence to the mature region was not prerequisite. From the expression of the ROL mutants with deletions at the N-terminal end of the prosequence together with mROL in trans, the residues from 20 to 37 in the prosequence were essential for the secretion, and those from 38 to 57 were essential for the formation of the active ROL and might play a role as an intramolecular chaperone. The results using the fragment of the prosequence confirmed that these residues (20-57) were significant for in vivo folding and secretion of active mROL.

Amino Acid Sequence↗

PubMed2001

Quantitative evaluation of the enhanced green fluorescent protein displayed on the cell surface of Saccharomyces cerevisiae by fluorometric and confocal laser scanning microscopic analyses.

The number of foreign protein molecules expressed on the cell surface of the budding yeast Saccharomyces cerevisiae by cell surface engineering was quantitatively evaluated using enhanced green fluorescent protein (EGFP). The emission from EGFP on the cell surface was affected by changes in pH. The amount of EGFP on the cell surface, displayed as alpha-agglutinin-fusion protein under control of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) promoter, was determined at the optimum pH of 7.0. The fluorometric analysis and the image analysis by confocal laser scanning microscopy (CLSM) showed a similar number of molecules displayed on the cell surface, demonstrating that 10(4)-10(5) molecules of alpha-agglutinin-fused molecules per cell were expressed. Furthermore, the amount of fluorescent protein expressed on cells harboring a multicopy plasmid was three to four times higher than that on cells harboring the gene integrated into the genome.

Arabidopsis↗

PubMed2001

Repression of fatty-acyl-CoA oxidase-encoding gene expression is not necessarily a determinant of high-level production of dicarboxylic acids in industrial dicarboxylic-acid-producing Candida tropicalis.

The synthesis of dicarboxylic acids (DCAs) in Candida tropicalis is thought to be induced by a decrease in fatty acyl-CoA-oxidase activity. However, in the present study we demonstrate that repression of the POX4 gene, encoding fatty acyl-CoA oxidase, does not directly lead to high-level production of DCAs. No fatty acyl-CoA-oxidase activity was detected if the POX4 gene of C. tropicalis strain 1098 (wild-type strain) was disrupted. Furthermore, introduction of the POX4 gene from C. tropicalis strain M1210A3, which is a mutant derived from strain 1098 and is used as an industrial DCA-producing strain, still exhibited low-level fatty acyl-CoA-oxidase activity. Nevertheless, production of DCA was not observed in either case. Furthermore, the increase in acyl-CoA-oxidase activity by expression of the POX4 gene in strain M1210A3 did not reduce high-level production of DCA. These results suggest that alterations in acyl-CoA-oxidase activity are not necessarily related to production of DCA in industrial DCA-producing C. tropicalis M1210A3.

Acyl-CoA Oxidase↗

PubMed2001

Spacer-mediated display of active lipase on the yeast cell surface.

We have constructed a Saccharomyces cerevisiae strain displaying an active lipase on the cell surface by cell surface engineering. The gene encoding Rhizopus oryzae lipase (ROL) was fused with the genes encoding the pre-alpha-factor leader sequence and the C-terminal half of alpha-agglutinin including the glycosylphosphatidylinositol-anchor attachment signal. The constructed gene was overexpressed under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter. Linker peptides (spacers) consisting of the Gly/Ser repeat sequence were inserted at the C-terminal portion of ROL to enhance lipase activity by preserving the conformation of the active site near the C-terminal portion. Localization of the expressed ROL on the cell surface was confirmed by immunofluorescence microscopy. The ROL displayed on the yeast cell wall exhibited activity toward soluble 2,3-dimercaptopropan-1-ol tributyl ester (BALB) and insoluble triolein. The insertion of linker peptides effected the activity towards BALB, thereby demonstrating that the optimal length of linker peptides was present. The activity towards triolein was higher in lipases with longer linker peptides. ROL displayed on the cell wall exhibited a comparable and/or higher activity towards triolein than the secreted form of the enzyme. This is the first report of an active lipase displayed on the cell surface. Furthermore, insertion of a linker peptide of the appropriate length as a spacer may be an improved method to effectively display enzymes, especially those having the active region at the C-terminal portion, on the cell surface.

Agglutinins↗

PubMed2001

Yeast whole-cell biocatalyst constructed by intracellular overproduction of Rhizopus oryzae lipase is applicable to biodiesel fuel production.

Yeast whole-cell biocatalysts for lipase-catalyzed reactions were constructed by intracellularly overproducing Rhizopus oryzae lipase (ROL) in Saccharomvces cerevisiae MT8-1. The gene encoding lipase from R. orvzae IFO4697 was cloned, and intracellular overproduction systems of a recombinant ROL with a pro-sequence (rProROL) were constructed. When rProROL from R. oryzae IFO4697 was produced under the control of the 5'-upstream region of the isocitrate lyase gene of Candida tropicalis (UPR-ICL) at 30 degrees C for 98 h by two-stage cultivation using SDC medium (SD medium with 2% casamino acids) containing 2.0% and 0.5% glucose, intracellular lipase activity reached levels up to 474.5 IU/l. These whole-cell biocatalysts were permeabilized by air-drying and used for the synthesis of methyl esters (MEs), a potential biodiesel fuel, from plant oil and methanol in a solvent-free and water-containing system. The ME content in the reaction mixture was 71 wt% after a 165-h reaction at 37 degrres C with stepwise addition of methanol. These results indicate that an efficient whole-cell biocatalyst can be prepared by intracellular overproduction of lipase in yeast cells and their permeabilization.

Amino Acid Sequence↗