Search PubMed⌕ Search

Biomedical subjects

A Toyoda

Publications and source records attributed to A Toyoda.

At least 37 records · Page 2Linked to original sources
PubMed1998

A novel multiple PDZ domain-containing molecule interacting with N-methyl-D-aspartate receptors and neuronal cell adhesion proteins.

At synaptic junctions, pre- and postsynaptic membranes are connected by cell adhesion and have distinct structures for specialized functions. The presynaptic membranes have a machinery for fast neurotransmitter release, and the postsynaptic membranes have clusters of neurotransmitter receptors. The molecular mechanism of the assembly of synaptic junctions is not yet clear. Pioneering studies identified postsynaptic density (PSD)-95/SAP90 as a prototypic synaptic scaffolding protein to maintain the structure of synaptic junctions. PSD-95/SAP90 belongs to a family of membrane-associated guanylate kinases and binds N-methyl-D-aspartate receptors, potassium channels, and neuroligins through the PDZ domains and GKAP/SAPAP/DAP through the guanylate kinase (GK) domain. We performed here a yeast two-hybrid screening for SAPAP-interacting molecules and identified a novel protein that has an inverse structure of membrane-associated guanylate kinases with an NH2-terminal GK-like domain followed by two WW and five PDZ domains. It binds SAPAP through the GK-like domain and NMDA receptors and neuroligins through the PDZ domains. We named this protein S-SCAM (synaptic scaffolding molecule) because S-SCAM may assemble receptors and cell adhesion proteins at synaptic junctions.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Cloning and chromosomal localization of a paralog and a mouse homolog of the human transaldolase gene.

A sequence homologous to the transaldolase gene (TALDO) was identified in a polymorphic cosmid DNA mapped on human chromosome 11p15 by exon trapping with pSPL3. Analysis of lambda clones contiguous to the cosmid clone showed that the related gene (TALDOR) consists of 8 exons spanning approximately 19kb from the translation start site to the polyadenylation signal. The exon sequence of TALDOR was almost identical with that of TALDO localized on 1p33-34. 1, but its exons corresponding to exons 4 and 5 of TALDO were found to be split by 4 introns in TALDOR. To examine the evolutionary conservation of two genes for transaldolase, we have isolated the cDNA for its mouse homolog and determined the nucleotide sequence covering the complete coding region. Fluorescence in situ hybridization using the cDNA as a probe showed that the mouse transaldolase gene (Taldo) is localized on chromosome 7 F3-F4 as a single copy gene. This chromosomal region is known to be syntenic to human chromosome 11p15 rather than to 1p33-p34.1, suggesting that TALDOR is the ancestral form. The existence of TALDOR implies a duplication of the mammalian transaldolase gene after divergence of rodent and primate.

Amino Acid Sequence↗
PubMed1998

Molecular cloning and characterization of rat lin-10.

In Caenorhabditis elegans, the vulval induction is mediated by tyrosine kinase receptor/Ras signal transduction pathway composed of the lin-3, let-23, and let-60 products. In addition to these gene products, the lin-2, lin-7, and lin-10 products are also implicated in this pathway. Lin-2 encodes a MAGUK and lin-7 encodes a small protein with one PDZ domain. The lin-10 product has no homology to known proteins. Here, we have cloned a rat homologue of the lin-10 product and characterized it. Rat lin-10 is ubiquitously expressed in various rat tissues and distributed in both the cytosol and membrane fractions. In brain, however, rat lin-10 is distributed only in the membrane fraction and enriched in the synaptic plasma membrane and postsynaptic density fractions. These results suggest that rat lin-10 is involved at least in synaptic functions in brain.

Animals↗
PubMed1997

Binding of neuroligins to PSD-95.

PSD-95 is a component of postsynaptic densities in central synapses. It contains three PDZ domains that localize N-methyl-D-aspartate receptor subunit 2 (NMDA2 receptor) and K+ channels to synapses. In mouse forebrain, PSD-95 bound to the cytoplasmic COOH-termini of neuroligins, which are neuronal cell adhesion molecules that interact with beta-neurexins and form intercellular junctions. Neuroligins bind to the third PDZ domain of PSD-95, whereas NMDA2 receptors and K+ channels interact with the first and second PDZ domains. Thus different PDZ domains of PSD-95 are specialized for distinct functions. PSD-95 may recruit ion channels and neurotransmitter receptors to intercellular junctions formed between neurons by neuroligins and beta-neurexins.

Amino Acid Sequence↗
PubMed1997

SAPAPs. A family of PSD-95/SAP90-associated proteins localized at postsynaptic density.

PSD-95/SAP90 is a member of membrane-associated guanylate kinases localized at postsynaptic density (PSD) in neuronal cells. Membrane-associated guanylate kinases are a family of signaling molecules expressed at various submembrane domains which have the PDZ (DHR) domains, the SH3 domain, and the guanylate kinase domain. PSD-95/SAP90 interacts with N-methyl-D-aspartate receptors 2A/B, Shaker-type potassium channels, and brain nitric oxide synthase through the PDZ (DHR) domains and clusters these molecules at synaptic junctions. However, neither the function of the SH3 domain or the guanylate kinase domain of PSD-95/SAP90, nor the protein interacting with these domains has been identified. We have isolated here a novel protein family consisting of at least four members which specifically interact with PSD-95/SAP90 and its related proteins through the guanylate kinase domain, and named these proteins SAPAPs (SAP90/PSD-95-Associated Proteins). SAPAPs are specifically expressed in neuronal cells and enriched in the PSD fraction. SAPAPs induce the enrichment of PSD-95/SAP90 to the plasma membrane in transfected cells. Thus, SAPAPs may have a potential activity to maintain the structure of PSD by concentrating its components to the membrane area.

Amino Acid Sequence↗
PubMed1997

Possible nicotinic receptor-mediated modulation of synaptic transmission in nucleus of the solitary tract.

Signal transmission from afferent nerves to neurons in the nucleus of the solitary tract (NTS) may be mediated partially by nicotinic acetylcholine receptors (nAChRs). Here, we investigated nAChR-mediated signal transmission using rat NTS slices. First, we characterized nAChRs by obtaining patch-clamp recordings from NTS neuronal cell bodies. Under whole cell voltage-clamp conditions at -60 mV, application of nicotine induced an inward current, and this effect was blocked by hexamethonium. In outside-out patch recordings, nicotine was seen to induce a hexamethonium-sensitive single-channel current. Second, we investigated nAChR-mediated signal transmission. Fast synaptic transmission mediated by nAChRs was not detected. The action of diffusible acetylcholine (ACh) on nAChRs was then tested using the outside-out patches excised from NTS neurons as probes for ACh. When the patch was placed at a distance of 20-30 microm from the cell body, single-channel currents were recorded, and these were inhibited by hexamethonium. The frequency of channel opening was increased by high-extracellular potassium concentration solution suggesting the voltage-dependent release ofACh that acts on nAChRs. These results suggested that nAChR-mediated signal transmission from sensory afferents to NTS neurons is in part mediated by diffusible ACh.

Acetylcholine↗
PubMed1997

[Clinical study on azithromycin in 10% fine granules and 100mg capsules in the field of pediatrics].

Azithromycin (AZM), a new oral macrolide antibiotic, in 10% fine granules or 100 mg capsules was given to pediatric patients to treat various infections. The following results were obtained in our studies of AZM for its antibacterial activities against clinical isolates, its pharmacokinetics, its efficacy, and its safety. 1. MICs of AZM, erythromycin (EM) and clarithromycin (CAM) were determined against a total of 57 strains all at 10(6) cfu/ml. Among Gram-positive cocci, MICs of AZM ranged from 0.78 to > 100 micrograms/ml against Staphylococcus aureus (20 strains), from 0.05 to 0.1 microgram/ml against Streptococcus pyogenes (11 strains), and from 0.0125 to 3.13 micrograms/ml against Streptococcus pneumoniae (10 strains). These MICs were similar to those of the other macrolides. Among Gram-negative bacilli, MICs of AZM were 0.05 micrograms/ml against Moraxella subgenus Branhamella catarrhalis (1 strain), from 0.78 to 3.13 micrograms/ml against Haemophilus influenzae (9 strains), 0.78 micrograms/ml against Haemophilus parainfluenzae (1 strain) and 6.25 micrograms/ml against salmonella sp. (1 strain). These values were similar to or lower than those of the other macrolides. Against Mycoplasma pneumoniae, MICs of AZM were < or = 0.0008 micrograms/ml in three strains. One strain of M. pneumoniae showed tolerance to AZM at MIC 25 micrograms/ml. The other agents exhibited higher MIC than AZM against this organism. 2. Plasma samples were collected from five patients receiving fine granules and four patients receiving capsules for drug level determination. The patients received AZM at 10.0 approximately 16.3 mg/kg body weight once daily for 3 days. Drug concentrations in plasma at two hours after Day 3 dosing were in a range between 0.02 and 0.19 micrograms/ml for fine granules and were in a range between 0.11 and 0.42 micrograms/ml for capsules. 3. Urine samples were collected from four patients receiving fine granules and four patients receiving capsules. Drug levels were determined to be 3 micrograms/ml at post-treatment 48 hours for fine granules and post-treatment 72 hours for capsules. Urinary excretion rates of AZM in three patients on capsules lied in a range between 4.69 and 10.17%. 4. Effectiveness of AZM in fine granules was evaluated in 128 patients having a total of 19 different infections. AZM was rated "excellent" in 51 patients, "good" in 63, "fair" in 8, "poor" in 6, resulting in an efficacy rate of 89.1%. Effectiveness of AZM in capsular form was evaluated in 23 patients with five different infections. AZM was found "excellent" in 13 patients and "good" in 10, resulting in an efficacy rate of 100%. 5. AZM in fine granules eradicated 45 strains of 54 in 8 different bacteria. AZM in capsules eradicated 9 strains of 10 strains in 6 different bacteria. 6. As for adverse reactions, one patient complained of eruption, one vomiting, one loose stool, five diarrhea, when administered with fine granular form of AZM. One patient on AZM capsules experienced urticaria and vomiting. 7. As for abnormal laboratory changes, three patients were found with decreased WBC, seven with increased eosinophil, two with increased GOT and GPT, one with increased GPT. They were all on fine granular form of AZM. As far as abnormalities found in patients administered with AZM in capsular form, two showed decreased WBC, one decreased WBC along with increased eosinophil, and three increased eosinophil.

Adolescent↗
PubMed1996

Isolation and analysis of a novel gene, HXC-26, adjacent to the rab GDP dissociation inhibitor gene located at human chromosome Xq28 region.

We screened potential promoter regions from NotI-linking cosmid clones mapped on human chromosome Xq28 region with our constructed trapping vector and isolated six fragments containing transcription activity. Using one of the obtained fragments as a probe, a novel gene was isolated by screening a human skeletal muscle cDNA library. The isolated cDNA, termed HXC-26, contained an open reading frame of 975 nucleotides encoding 325 amino acids (38,848 Da). The HXC-26 gene was composed of 13 exons that span approximately 8 kb. Several potential GC boxes were found in the putative promoter region, but no typical TATA box. The HXC-26 gene associated with a CpG island was located adjacent to the rab GDP dissociation inhibitor (GDI) gene.

Amino Acid Sequence↗
PubMed1995

Mode of activation of the GC box/Sp1-dependent promoter of the human NADH-cytochrome b5 reductase-encoding gene.

Many eukaryote promoters, particularly those for so-called housekeeping genes, have multiple GC boxes which are the binding sites of the transcription factor, Sp1. It has been proposed that Sp1 binds to the multiple GC boxes, and then the GC box-bound Sp1 interact with each other to synergistically stimulate transcription. Here, we describe a Sp1-dependent promoter which does not necessarily fit the synergistic activation mechanism. The promoter of the human NADH-cytochrome b5 reductase-encoding gene (CYTB5R) possesses five potential GC box sequences. Deletion and mutagenesis studies coupled with CAT assays revealed that three out of five GC box-like sequences were functionally active and activated transcription additively (rather than synergistically). Our results suggested that Sp1-mediated activation of transcription occurs in a promoter context-dependent manner.

Animals↗
PubMed1995

Assignment of a human autoimmune antigen, p80-coilin gene to chromosome 17q21-q23 and of its possible pseudogene to chromosome 14.

In order to determine the chromosomal locations of an autoimmune antigen, the coilin gene and its pseudogene, we amplified the segments of the two genes by the polymerase chain reaction (PCR) and screened a panel of somatic cell hybrids for the presence of the gene products. The results indicate that the human coilin gene and its pseudogene can be assigned to chromosome 17 and chromosome 14, respectively. Further analysis of cell hybrids bearing chromosome 17 with various deletions localized the coilin gene to the region q21-q23.

Animals↗
PubMed1995

Incidence and characteristics of clonal hematopoiesis in remission of acute myeloid leukemia in relation to morphological dysplasia.

We studied 34 patients in remission of acute myeloid leukemia (AML) by performing clonal analysis of peripheral blood polymorphonuclear (PMN) cells and mononuclear (MN) cells, using X-linked DNA polymorphisms, in conjunction with the assessment of morphological myelodysplastic changes, performed by a scoring method. Nine patients demonstrated a non-random or skewed X-chromosome inactivation pattern in PMN cells. Three of these nine patients had an apparently random pattern in MN cells (group A), whereas the remaining six patients demonstrated no difference between the inactivation patterns of PMN and MN cells (group B). The PMN cells of the other 25 patients showed a random X-chromosome inactivation pattern, and the patterns of the PMN cells did not differ from those of the MN cells (group C). The scores for myelodysplasia were high (> or = 4) in all three patients in group A, intermediate (2-3) in two patients and low (score < 2) in four patients in group B, and intermediate in five patients and low in 20 patients in group C. The duration of remission in patients with a myelodysplasia score of > or = 2 was significantly shorter than that of patients with a score of < 2 (P < 0.01). We conclude that clonal remission actually occurs with myelodysplastic features in some patients with AML (around 10%, group A). It is possible that this clonal analysis may not be sensitive enough to detect the preleukemic clone with myelodysplastic features when this clone constitutes only a minor population of remission hematopoiesis. To further elucidate the biology of such preleukemic clones it is essential to develop more sensitive molecular methods for the detection of genetic abnormalities specific to preleukemic hematopoiesis.

Adolescent↗
PubMed1994

Cloning and characterization of a pair of genes that stimulate the production and secretion of Zymomonas mobilis extracellular levansucrase and invertase.

A 1.7-kb DNA fragment cloned from Zymomonas mobilis genomic DNA complemented the inability to grow on sucrose of a Suc- mutant of Z. mobilis that was deficient in the production of both extracellular levansucrase and invertase. Analysis of the nucleotide sequence of the fragment found two open reading frames (ORFs), both of which did not correspond to the structural gene for the levansucrase or the invertase. By subcloning each ORF into two different Suc- mutants of Z. mobilis, it has been found that the first ORF (gene zliE) activates the production of the extracellular levansucrase and invertase, and the second ORF (gene zliS) stimulates the secretion of the two enzymes. Gene zliS might contribute to the secretion of proteins having no signal peptide. The expression of zliE and zliS seemed to be under the control of the same promoter.

Amino Acid Sequence↗
PubMed1993

Sequence-tagged NotI sites of human chromosome 21: sequence analysis and mapping.

We isolated and analyzed 19 NotI site-containing clones specific for human chromosome 21. The overall process consisted of selective isolation of NotI site-containing clones from flow-sorted chromosome 21 libraries, selection of independent clones by their restriction patterns and nucleotide sequences, and assignment of the clones to chromosome 21. Sequence analysis showed that the regions around the NotI sites had features typical of CpG islands, such as extremely high GC content, high-frequency appearance of CpG dinucleotide sequences, and lack of methylation of these CpGs. PCR conditions for these extremely G + C-rich templates were optimized to establish these NotI sites as sequence-tagged sites.

Base Sequence↗
PubMed1993

Simple purification method for a Vibrio vulnificus hemolysin by a hydrophobic column chromatography in the presence of a detergent.

A Vibrio vulnificus hemolysin (VVH) was purified by two steps of hydrophobic column chromatography on Phenyl-Sepharose HP. The first chromatography was carried out at pH 6.0. In this pH condition, VVH efficiently bound to the column, but the hemolysin fraction eluted was accompanied with colored substance(s). To eliminate this colored substance, the second chromatography was carried out at pH 9.8 in the presence of 1% 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS), a zwitterionic detergent. Homogeneity of the hemolysin thus obtained was shown by polyacrylamide gel electrophoresis. The specific activity increased 33,600 times and the yield was 35%. The method is simple and useful to supply enough VVH for study of the role of the hemolysin in the infection by V. vulnificus or on the mechanism of action of the hemolysin.

Chromatography↗
PubMed1993

A clonal study of hematopoiesis using the M27 beta probe: aberrant band patterns caused by incomplete digestion of a methyl-sensitive enzyme in the the inactive X-chromosome.

The M27 beta probe has been used to determine the clonality of human tumors, based upon X-chromosome inactivation. However, it occasionally gives rise to aberrant results. In this study, the M27 beta probe was used for clonal analysis in Japanese women with clonal stem cell disorders and in those with normal hematopoiesis. Restriction digestion with PstI indicated heterozygosity for the DXS255 locus in 41 out of 50 individuals (82%). Further digestion with HpaII in heterozygous women led to four distinct band patterns: I, both fragments were partially digested; II, either one of the two fragments was completely digested; III, a three-band pattern; and IV, neither fragment was digested. Of 21 hematologically normal females, 17 (81%) and four (19%) had patterns I and III, respectively. In some subjects with pattern I, imbalanced HpaII digestion in the two alleles was seen. Fifteen (65%) of the 23 patients with clonal stem cell disorders had pattern II, while the remainder (35%) had pattern IV. The normal tissues of three acute myeloid leukemia patients with pattern IV all revealed pattern I. It is possible that the aberrant band patterns could be caused by incomplete HpaII digestion in inactive X-chromosomes. In this study, we propose a hypothesis whereby, in normal tissues, aberrant cells, the DXS255 locus of which is not digested with HpaII despite their inactive status, would be mixed with cells demonstrating the usual methylation pattern. In normal tissues, complex of proportion of aberrant cells and skewed Lyonization could produce a variety of band patterns. If a cell with the usual methylation pattern proliferated monoclonally, pattern II would be seen: whereas if an aberrant cell proliferated, pattern IV would be demonstrated.

Blotting, Southern↗