Biomedical subjects

Akio Kobayashi

Publications and source records attributed to Akio Kobayashi.

At least 55 records · Page 3Linked to original sources

PubMed2004

Guidelines for treatment of ulcerative colitis in children.

This paper introduces the guidelines for treatment of ulcerative colitis in children, created by the working group of the Japanese Society for Pediatric Gastroenterology, Hepatology and Nutrition (Chair: Yuichiro Yamashiro) and the Japanese Society for Pediatric Inflammatory Bowel Disease (IBD) (Chair: Akio Kobayashi). The ideas of the working group, with regard to the fundamental differences in medical treatment between children and adults, included: (1) for children, intensive medical treatment including appropriate systemic management is important during the acute phase of illness. (2) Treatment with steroids, which can cause growth disturbances, should not be continued for long periods of time. (3) Pulsed steroid therapy, selective removal of blood cells, and intravenous infusion of cyclosporin should be included in the therapeutic option for severe and fluminant cases.

Child↗

PubMed2004

Biosynthetic pathway for the C45 polyprenol, solanesol, in tobacco.

Feeding experiments were independently performed with [1-13C]deoxy-D-xylulose triacetate and (RS)-[2-13C]mevalonolactone in the tobacco plant. The labeling pattern for solanesol was elucidated to reveal that the isoprene moiety of solanesol would be derived from deoxy-xylulose. The result strongly suggests that tobacco solanesol is biosynthesized via the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway.

Butadienes↗

PubMed2004

Cloning and characterization of farnesyl diphosphate synthase from the rubber-producing mushroom Lactarius chrysorrheus.

Farnesyl diphosphate is involved in rubber biosynthesis as an initiating substrate for both polyprenol and mushroom rubber. So far, we have isolated the cDNA of a farnesyl diphosphate synthase (FPS) for the first time from a rare rubber-producing mushroom, Lactarius chrysorrheus, by the degenerate RT-PCR technique based on sequence information of FPS genes from fungi and yeasts. The open reading frame was clarified to encode a protein of 381 amino acid residues with a calculated molecular weight of 42.9 kDa. The deduced amino acid sequence of L. chrysorrheus FPS showed about 50% identity with those of other fungi and yeasts as well as plants. We expressed the cDNA of L. chrysorrheus FPS in Escherichia coli as a glutathione-S-transferase (GST)-fusion protein. The purified obtained protein showed FPS activity in which geranyl diphosphate (GPP) served as primary substrate, with a 2.4-fold higher k(cat)/K(m) value for GPP than for dimethylallyl diphosphate (DMAPP).

Agaricales↗

PubMed2003

Requirement of Lim1 for female reproductive tract development.

Lim1 encodes a LIM-class homeodomain transcription factor that is essential for head and kidney development. In the developing urogenital system, Lim1 expression has been documented in the Wolffian (mesonephric) duct, the mesonephros, metanephros and fetal gonads. Using, a Lim1 lacZ knock-in allele in mice, we identified a previously unreported urogenital tissue for Lim1 expression, the epithelium of the developing Müllerian duct that gives rise to the oviduct, uterus and upper region of the vagina of the female reproductive tract. Lim1 expression in the Müllerian duct is dynamic, corresponding to its formation and differentiation in females and regression in males. Although female Lim1-null neonates had ovaries they lacked a uterus and oviducts. A novel female mouse chimera assay was developed and revealed that Lim1 is required cell autonomously for Müllerian duct epithelium formation. These studies demonstrate an essential role for Lim1 in female reproductive tract development.

Animals↗

PubMed2003

Methanol production is enhanced by expression of an Aspergillus niger pectin methylesterase in tobacco cells.

Tobacco suspension culture cell (Nicotiana tabacum, BY2) was transformed with an Aspergillus niger pectin methylesterase (PME; EC 3.1.1.11) cDNA under the control of cauliflower mosaic virus (CaMV) 35S promoter. The transformant indicated a significant rise of PME and the level of methanol in the transformant increased by 28.7% compared to the vector control transformant. This is the first report of methanol overproduction in plant cells by means of genetic engineering.

Aspergillus niger↗

PubMed2003

Cloning and kinetic characterization of Arabidopsis thaliana solanesyl diphosphate synthase.

trans -Long-chain prenyl diphosphate synthases catalyse the sequential condensation of isopentenyl diphosphate (C(5)) units with allylic diphosphate to produce the C(30)-C(50) prenyl diphosphates, which are precursors of the side chains of prenylquinones. Based on the relationship between product specificity and the region around the first aspartate-rich motif in trans -prenyl diphosphate synthases characterized so far, we have isolated the cDNA for a member of trans -long-chain prenyl diphosphate synthases from Arabidopsis thaliana. The cDNA was heterologously expressed in Escherichia coli, and the recombinant His(6)-tagged protein was purified and characterized. Product analysis revealed that the cDNA encodes solanesyl diphosphate (C(45)) synthase (At-SPS). At-SPS utilized farnesyl diphosphate (FPP; C(15)) and geranylgeranyl diphosphate (GGPP; C(20)), but did not accept either the C(5) or the C(10) allylic diphosphate as a primer substrate. The Michaelis constants for FPP and GGPP were 5.73 microM and 1.61 microM respectively. We also performed an analysis of the side chains of prenylquinones extracted from the A. thaliana plant, and showed that its major prenylquinones, i.e. plastoquinone and ubiquinone, contain the C(45) prenyl moiety. This suggests that At-SPS might be devoted to the biosynthesis of either or both of the prenylquinone side chains. This is the first established trans -long-chain prenyl diphosphate synthase from a multicellular organism.

Alkyl and Aryl Transferases↗

PubMed2003

Quantitation of formate by solid-phase microextraction and gas chromatography--mass spectrometry utilizing a [13C]formate internal standard.

A new method for the analysis of formic acid was developed using gas chromatography-electron impact ionization mass spectrometry in the selected ion monitoring mode and solid-phase microextraction. Using this method with [13C]formic acid as an internal standard, the peak area ratio of [12C]formic acid/[13C]formic acid was not affected by differing methanol or sulfuric acid concentrations during the esterification and fiber adsorbing step. In comparison, the peak area ratio of formic acid/acetonitrile as detected by conventional GC with flame ionization detection was greatly affected by methanol or sulfuric acid concentrations. The formic acid calibration curve of our method showed excellent linearity over the range 5 to 200 microM. The within- and between-run assay relative standard deviations for the formic acid concentration were all less than 1.70%.

Calibration↗

PubMed2003

Phytotoxicity of the tetramic acid metabolite trichosetin.

Trichosetin, a tetramic acid-containing metabolite produced in the dual culture of Trichoderma harzianum and Catharanthus roseus (L.) G. Don callus, was subjected to phytotoxicity assays. In seedling growth assays, trichosetin inhibited root and shoot growth of all five plant species tested by damaging the cell membrane, as evidenced by the dose-dependent increase in electrolyte leakage and lipid peroxidation. Vital staining of trichosetin-treated Nicotiana tabacum BY-2 cells, with rhodamine 123, showed a weaker green fluorescence compared to controls indicating damaging effects on mitochondria. FDA-PI staining, to determine cell viability, indicated that cells of the trichosetin-treated roots were mostly dead.

Cell Survival↗

PubMed2003

Biochemical change in joint fluid after isometric quadriceps exercise for patients with osteoarthritis of the knee.

OBJECTIVE: The purpose of this study was to analyze the biochemical changes in the joint fluid, and pain relief resulting from isometric quadriceps exercise in patients with osteoarthritis of the knee. DESIGN: Nineteen osteoarthritic knees in 17 patients with joint effusion were included. The patients performed isometric quadriceps exercise for 3 months. Isometric muscle torque at 30 and 60 degrees flexion, pain as measured using the visual analog scale and biochemical markers in joint fluid were evaluated before and after the exercise. RESULTS: Pain score decreased from 3.9 to 2.3 after 12 weeks of exercise (P<0.001). Extension torque at 30 and 60 degrees knee flexion significantly increased from 4.7 to 6.9 kgm (47% increase, P<0.001) and from 10.8 to 12.6 kgm (17% increase, P<0.005) after 12 weeks of exercise. The molecular weight of hyaluronan increased from 2.11 to 2.40x10(6)(P<0.05) and the viscosity of joint fluid increased from 45.8 to 59.8 mPas after 12 weeks of exercise (P<0.05). Chondroitin 4-, 6-sulfate concentration in joint fluid decreased from 81.9 to 75.5 nmol/ml (P<0.05). CONCLUSIONS: Isometric quadriceps exercise resulted in significant changes in joint fluid biochemical parameters, and these changes, at least in part, may explain the ameliorative effect of muscle exercise for osteoarthritis of the knee.

Aged↗

PubMed2003

A facile transformation of Arabidopsis thaliana using ceramic supported propagation system.

Arabidopsis thaliana can be a useful model plant in the field of plant molecular biology because it is a sole dicotyledonous plant whose genome sequence has been completely determined at the present time. To develop functional genomics of A. thaliana, a large number of transgenic plants must be produced. However, transformation of the plants requires wide space and long time. For these reasons, a highly efficient method has been desired to be developed. In order to save space, the transformation system was improved, based on a new technology for plant propagation using ceramic tubes. The new method using ceramic tubes facilitated to prepare plants with a uniform growth level. In addition, the colander procedure after infiltration, which is one of tedious procedures, could be omitted. The new system without soil usage could cut down the cleaning up after experiment.

Journal Article↗

PubMed2003

Introduction of the archaebacterial geranylgeranyl pyrophosphate synthase gene into Chlamydomonas reinhardtii chloroplast.

Geranylgeranyl pyrophosphate (GGPP) synthase gene (gds) derived from a thermophilic Archae Sulfolobus acidocaldarius, was introduced into a unicellular green alga Chlamydomonas reinhardtii chloroplast. Heat treatment abolished the prenyltransferase activity of the wild strain, but the activity of the transforment remained. The transformant accumulated gds gene mRNA and translation product.

Journal Article↗

PubMed2003

Repeated chromosome splitting targeted to delta sequences in Saccharomyces cerevisiae.

We have previously developed a chromosome-splitting technique based on homologous recombination in Saccharomyces cerevisiae. To facilitate chromosome splitting at multiple sites, we focused on the delta sequences that are distributed in more than 200 copies throughout the yeast genome. We constructed a new chromosome-splitting vector harboring the YFLWdelta4 sequence and the hisG-URA3-hisG cassette, and transformed yeast cells with this vector. The karyotype analysis of transformants showed that chromosomes XIV, III, and IV, or other chromosomes are split. After the excision of the URA3 gene, the transformant with split chromosome IV was subsequently transformed with the same vector. Karyotype analysis revealed that further splitting occurred at chromosome X, the split chromosome IV, or other chromosomes. These results indicate that delta sequences are efficient target sites for repeated chromosome splitting at multiple sites with a single vector.

Journal Article↗

PubMed2003

Granulocyte adsorptive apheresis for pediatric patients with ulcerative colitis.

Granulocytapheresis (GCAP) has produced efficacy in adult patients with ulcerative colitis (UC) by adsorbing activated granulocytes and monocytes/macrophages. We retrospectively investigated efficacy and safety of GCAP in pediatric patients with active UC. Twelve steroid-refractory children (12.2 +/- 3.1 years old) were treated with GCAP, one session/week for 5-10 consecutive weeks. In 8 patients, clinical symptoms improved after two GCAP sessions. Normal body temperature, stool frequency, and disappearance of blood in stool were seen after 24.3 +/- 11.5 days. The endoscopic grade improved from 2.6 +/- 0.3 to 0.4 +/- 0.2. One patient who initially responded, developed bloody diarrhea later and 2 cases remained unchanged. The dose of steroid was tapered during GCAP therapy by 50%. No serious adverse effects were noted. Four of 8 cases relapsed 3.5 +/- 2.2 months after the last GCAP while on maintenance therapy, the other 4 were in remission up to 22.8 +/- 18.1 months. In conclusion, GCAP appears to be effective and well tolerated in children with steroid-refractory UC.

Adolescent↗

PubMed2003

Developmental genetics of the female reproductive tract in mammals.

The female reproductive tract receives the oocytes for fertilization, supports the development of the fetus and provides the passage for birth. Although abnormalities of this organ system can result in infertility and even death, until recently relatively little was known about the genetic processes that underlie its development. By drawing primarily on mouse mutagenesis studies and the analysis of human mutations we review the emerging genetic pathways that regulate female reproductive-tract formation in mammals and that are implicated in congenital abnormalities of this organ system. We also show that these pathways might be conserved between invertebrates and mammals.

Animals↗

PubMed2003

Polyethylene wear particles in synovial fluid after total knee arthroplasty.

The aims of the current study were to examine polyethylene particles in synovial fluid at an early stage, and to compare a newly introduced medial pivot total knee prosthesis with an established posterior-stabilized total knee prosthesis. Synovial fluid was obtained 1 year after knee arthroplasty from 17 patients with well-functioning prostheses (22 knees, 11 posterior-stabilized prostheses and 11 medial pivot prostheses) under complete sterile conditions. Polyethylene particles were isolated and analyzed by scanning electron microscopy. Particle size (equivalent circle diameter) was 0.78 +/- 0.08 microm (mean +/- standard error) in posterior-stabilized prostheses and 0.67 +/- 0.06 microm in medial pivot prostheses. Particle shape (aspect ratio) was 2.30 +/- 0.22 in posterior-stabilized prostheses and 1.90 +/- 0.16 in medial pivot prostheses. The total numbers of particles were 1.16 +/- 0.57 x 10(8) in posterior-stabilized prostheses and 9.01 +/- 2.95 x 10(6) in medial pivot prostheses. Particles were smaller and rounder in medial pivot prostheses than in posterior-stabilized prostheses, but the differences were not significant. The difference in the common logarithm of particle number was significant. The medial pivot prosthesis generated less wear particles than the posteriorstabilized prosthesis, and these findings may have an impact on the incidence of osteolysis and aseptic loosening.

Arthroplasty, Replacement, Knee↗

PubMed2003

A transient RNA interference assay system using Arabidopsis protoplasts.

Double-stranded RNA (dsRNA) induces sequence-specific gene silencing in eukaryotes through a process known as RNA interference (RNAi). RNAi is now used as a powerful tool for functional genomics in many eukaryotes, including plants. We herein report a dsRNA-mediated transient RNAi assay system using protoplasts from Arabidopsis mesophyll cells and suspension-cultured cells (cell line T87). Introduction of dsRNA into protoplasts led to marked silencing of target transgenes. Our assay system would provide a convenient and efficient way to induce RNAi in protoplasts of the model plant Arabidopsis thaliana.

Arabidopsis↗

PubMed2003

Urinary excretion of oxidative metabolites of bilirubin in fenofibrate-treated rats.

Bilirubin oxidative metabolites (BOM) were shown to be excreted into the urine in rats in which exaggerated oxidative stress was induced. We measured bilirubin (BR) and biopyrrins in the urine of rats treated with fenofibrate, a peroxisome proliferator, which is known to cause oxidative stress. Male Crj:CD(SD)IGS rats aged 6 weeks were treated orally with fenofibrate at 10, 400 and 800 mg/kg for 2 weeks. Urinary excretion of BR and BOM, and the plasma BOM levels were determined after the first dose and after 1-week and 2-week treatment. Urinary excretion of BOM was significantly and dose-dependently increased by fenofibrate treatment at 400 and 800 mg/kg. This became more prominent as the dosing period progressed and reached an 8-fold increase in the 400 mg/kg group and 11-fold increase in the 800 mg/kg group compared with the data before dosing on Day 14. Plasma BOM levels were increased 1.8-fold and 2.7-fold, respectively, at 400 and 800 mg/kg in fenofibrate-treated rats. At 800 mg/kg, there was also increased urinary excretion of BR (2-fold) on Day 14. These changes of BOM in the urine and plasma indicated that BR was oxidized by reactive oxygen species (ROSs), which were produced by treatment with fenofibrate. In conclusion, urinary excretion of BOM, which is a marker for oxidative stress, urinary excretion of BR and the plasma BOM levels were increased in rats treated with fenofibrate. Increased urinary excretions of BR and BOM, and increased plasma BOM levels are likely to be the consequence of physiological protection against the oxidative stress produced by fenofibrate. These findings suggest a possibility that analysis of BOM in the urine and plasma could be helpful in evaluating the degree of oxidative stress in vivo.

Animals↗

PubMed2003

Transformation of yeast using calcium alginate microbeads with surface-immobilized chromosomal DNA.

Yeast artificial chromosomes (YACs) are useful cloning vectors that have the capacity to carry large DNA inserts. The largest barrier to using such large DNA molecules in transformation experiments has been their physical instability in solution. We developed a new method of transforming yeast using chromosome-sized DNA. The method uses calcium alginate microbeads to immobilize high-density yeast chromosomal DNA. Chromosomal DNA immobilized on microbeads is physically stabilized compared with naked chromosomal DNA. The microbead-mediated transformation performed well, not only with respect to the transformation frequency with large DNA molecules (> 100 kb) but also in successful transformation using split chromosome DNA that exceeded 450 kb.

Adsorption↗