Search PubMed⌕ Search

Biomedical subjects

K Taira

Publications and source records attributed to K Taira.

At least 235 records · Page 13Linked to original sources
PubMed1990

In vivo RNA transcript-releasing plasmid possessing a universal pseudo-terminator by means of artificial ribozymes.

RNA transcript-releasing plasmid has been constructed by means of artificial hammerhead ribozymes. In this specific construct of pGENE8459v3 the ribozyme targeted for SFL1 gene (a yeast suppressor gene for flocculation) was fused between two other ribozymes called 5'-processing and 3'-processing ribozymes. Since the "Ribozyme for SFL1" portion (cassette) can be replaced by other RNA sequences, it is now possible to produce any RNAs with defined 5'- and 3'- ends.

Base Sequence↗
PubMed1990

[Ristocetin induced platelet aggregation in children with nephrotic syndrome].

In 22 children with steroid responsive nephrotic syndrome (SRNS), we examined platelets aggregability to ristocetin, and the data obtained wre compared with negative charge on platelet membrane based on the binding of cationic dye alcian blue 8GX (AB) or plasma levels of von Willebrand factor antigen (vWF:Ag) and ristocetin cofactor (Rcof) activity. At the initial or relapse stage of SRNS, the enhanced platelet aggregation to ristocetin was observed, and correlated with the decreased alcian blue binding to platelets. Ristocetin-induced vWF:Ag binding to platelets by using 125I-vWF was significantly increased. In addition, ristocetin-induced platelets aggregation (RIPA) using washed nephrotic platelets still enhanced as found in the patient's platelets rich plasma (PRP), even when it was resuspended into normal plasma. These results suggest that the decrease of platelet surface negative charge play an important role of heighten RIPA found in children with SRNS.

Adolescent↗
PubMed1989

Cyclic oxyphosphoranes as model intermediates during splicing and cleavage of RNA: ab initio molecular orbital calculations on the conformational analysis.

Ab initio molecular orbital calculations have been carried out on hydrated adducts of methyl ethylene phosphate as a model intermediate during cleavage of RNA. Upon rotating the apical methoxyl group two kinds of stable conformers and two kinds of rotational transition states are located, the most stable conformation being gs-G where the dihedral angle between the apical methyl group and the basal ring oxygen is calculated to be 76 degrees. In this gs-G conformation one of the lone pairs on the apical oxygen is oriented antiperiplanar to the basal ring ester bond. The torsional energy required to rotate the methyl group about the phosphorus-apical oxygen bond leading to ts-C conformation, where the methyl group is eclipsed with the ring oxygen, is calculated to be 5.2 kcal/mol. Judging from the published substrate's coordinates in the RNase environment, the expected pentacoordinate-intermediate/transition state during the cleavage of RNA appears to be, in fact, the most stable gs-G conformation.

Indicators and Reagents↗
PubMed1989

Fragments of urinary fibrin/fibrinogen degradation products and cross-linked fibrin degradation products in various renal diseases.

In children with several kinds of glomerular disease, fragments of fibrin/fibrinogen degradation products (FDP) and cross-linked fibrin degradation products (XLFDP) in the urine were investigated by autoradiography using western blotting method. Results were compared with selectivity of proteins observed in cases of proteinuria, or with histological findings. Patients with nephrotic syndrome exhibited slightly increased amount of urinary FDP, consisted mainly of X and Y fragments. On the other hand, in cases of proliferative glomerulonephritis, such as acute glomerulonephritis, purpura nephritis, Ig A nephropathy, systemic lupus erythematosus, or hemolytic uremic syndrome, increased FDP, including XLFDP, was detected in the urine. In these cases, FDP was consisted mainly of fragments X, Y, and D-dimer, and could not be correlated with the degree of mesangial proliferation or with urinary protein selectivity. It was concluded that the increased urinary FDP and XLFDP were derived not only from filtration of plasma fibrinogen or FDP, but also from fibrinolysis of intraglomerular fibrin deposits.

Acute Disease↗
PubMed1989

Antithrombin III in children with various renal diseases.

Levels of antithrombin III (AT-III) activity and antigen in plasma and urine in children with renal diseases, and their correlation with the light microscopic findings of kidney tissue and the fluorescence of glomeruli, were investigated. AT-III activity in plasma was reduced slightly during the acute stage of acute glomerulonephritis and moderately in the relapse stage of nephrotic syndrome, whereas a small increase of AT-III antigen level in urine was noted in the acute stage of glomerulonephritis and considerably more was observed during the relapse stage of nephrotic syndrome. During the acute stage of glomerulonephritis or in some primary persistent glomerulonephritis (IgA nephritis, non-IgA nephritis), Henoch-Schönlein purpura nephritis and nephrotic syndrome, localization of small amounts of AT-III was noted on the capillary walls of glomeruli. These findings were in parallel with the proliferative changes of glomeruli. However, the AT-III localization did not change in parallel with the light microscopic findings or degree of the fluorescence of the fibrinogen/fibrin-related antigen. It was thought that the existence of AT-III antigen on the capillary walls of the glomeruli might be associated with the inhibition of excessive fibrin formation by AT-III.

Acute Disease↗
PubMed1989

Molecular relationship of chromosomal genes encoding biphenyl/polychlorinated biphenyl catabolism: some soil bacteria possess a highly conserved bph operon.

All the genes we examined that encoded biphenyl/polychlorinated biphenyl (PCB) degradation were chromosomal, unlike many other degradation-encoding genes, which are plasmid borne. The molecular relationship of genes coding for biphenyl/PCB catabolism in various biphenyl/PCB-degrading Pseudomonas, Achromobacter, Alcaligenes, Moraxella, and Arthrobacter strains was investigated. Among 15 strains tested, 5 Pseudomonas strains and one Alcaligenes strain possessed the bphABC gene cluster on the XhoI 7.2-kilobase fragment corresponding to that of Pseudomonas pseudoalcaligenes KF707. More importantly, the restriction profiles of these XhoI 7.2-kilobase fragments containing bphABC genes were very similar, if not identical, despite the dissimilarity of the flanking chromosomal regions. Three other strains also possessed bphABC genes homologous with those of KF707, and five other strains showed weak or no significant genetic homology with bphABC of KF707. The immunological cross-reactivity of 2,3-dihydroxybiphenyl dioxygenases from various strains corresponded well to the DNA homology. On the other hand, the bphC gene of another PCB-degrading strain, Pseudomonas paucimobilis Q1, lacked genetic as well as immunological homology with any of the other 15 biphenyl/PCB degraders tested. The existence of the nearly identical chromosomal genes among various strains may suggest that a segment containing the bphABC genes has a mechanism for transferring the gene from one strain to another.

Bacteria↗
PubMed1989

[Immunoelectron microscopic observation of membranous nephropathy in children using protein A-gold complex method].

The ultrastructural localization of immunoglobulins (IgG, IgA, IgM), complement component (C3c), or fibrinogen-related antigen (FRA) was investigated on 5 biopsy samples from 5 children with idiopathic MN or lupus nephritis using protein A-gold (PAG) complex method. The immunoreactivity of IgG was essentially confined to the mesangial and subepithelial electron-dense deposit (EDD) in all of 5 children, and more intense staining of IgG was observed in 3 children with stage II of MN than those with stage I and stage III of MN. Double immunocytochemical staining showed the same distribution of both IgG and IgM or both IgG and FRA in subepithelial EDD in 2 of 5 children. These findings suggest that IgG deposits are associated with the formation of subepithelial EDD in MN, and raise the possibility that IgM and FRA deposits may result from entrapment and/or immunological reaction.

Adolescent↗
PubMed1988

Cloning and nucleotide sequence of the 2,3-dihydroxybiphenyl dioxygenase gene from the PCB-degrading strain of Pseudomonas paucimobilis Q1.

The bphC gene encoding 2,3-dihydroxybiphenyl dioxygenase was cloned from biphenyl-degrading and chlorinated biphenyl-degrading Pseudomonas paucimobilis Q1, and its complete nucleotide sequence was determined. The DNA-derived protein sequence provides the primary structure of 298 amino acids. Polyclonal antibodies raised against this protein from P. paucimobilis Q1 failed to cross-react with the previously isolated 2,3-dihydroxybiphenyl dioxygenase from Pseudomonas pseudoalcaligenes KF707 [Furukawa, K., & Arimura, N. (1987) J. Bacteriol. 169, 924-927. Furukawa, K., Arimura, N., & Miyazaki, T. (1987) J. Bacteriol. 169, 427-429], despite the close similarities of these proteins in terms of their native as well as subunit molecular weights, cofactor, and enzymatic activities. The sequence homology of the 2,3-dihydroxybiphenyl dioxygenase from the two different sources is examined.

Amino Acid Sequence↗
PubMed1988

A vector stimulator for neurophysiological studies of periodontal mechanosensitive units.

This paper describes a newly designed vector stimulator which can independently stimulate both sides of an animal's canine or incisor teeth to analyse the functional properties of periodontal mechanosensitive (PM) units. The stimulator was designed so as to control and stimulus direction (0 degree-360 degrees) and intensity (0-0.98 N) within the horizontal plane (vector), the rate of application (0.049-490 N/s), and the duration (0-10 s). The stimulator is composed of electromagnetic drivers, a trapezoid-wave generator, and a stimulus monitor. The former is adopted from conventional pen drivers, and the latter two are composed of operational amplifier circuits. The vector stimulator was utilized to apply a stimulus force to the canine teeth of a cat, and the responses of the PM units were recorded in the somatosensory cerebral cortex.

Animals↗
PubMed1988

Evaluation of the importance of hydrophobic interactions in drug binding to dihydrofolate reductase.

The interaction of dihydrofolate reductase (DHFR) from Escherichia coli with drugs such as methotrexate (MTX) and 2,4-diamino-6,7-dimethylpteridine (DAM) has been studied by means of site-directed mutagenesis, fluorescence spectroscopy, and steady-state as well as transient kinetics. A strictly conserved residue at the dihydrofolate binding site of DHFR, phenylalanine-31, has been replaced with tyrosine or valine to ascertain the importance for binding of this hydrophobic amino acid, which interacts with both the pteridine ring and the p-aminobenzoyl moiety. The first mutation (Phe-31----Tyr) has a minimal effect on the binding of the classical inhibitor, DAM. On the other hand, the second mutation (Phe-31----Val) has increased the dissociation constant of DAM from the DHFR.NADPH.DAM ternary complex over 150-fold (greater than 3 kcal/mol). The dissociation constant of DAM from the (Val31-DHFR).DAM binary complex was too large to be measured fluorometrically. More importantly, these mutations have decreased the overall tight binding of MTX, from 100- to 140-fold (corresponding to a loss of binding energy of 2.2-2.4 kcal/mol) for the Tyr-31 and Val-31 mutants, respectively. These results indicate that hydrophobic interactions between MTX and DHFR are at least as important as formation of the MTX.DHFR salt bridge in the tight binding of MTX.

Binding Sites↗
PubMed1988

Intraglomerular deposition of fibrin/fibrinogen-related antigen in children with various renal diseases.

The localization of intraglomerular deposits of fibrin (Fb)/fibrinogen (Fg)-related antigen (FRA) in children with various glomerular diseases was determined by an immunohistopathologic method using an anti-Fg antibody capable of detecting FRA, an anti-D-dimer antibody capable of detecting crosslinked Fb (XLFb) and its derivatives (XLFbDP), and by a method using the effect of monochloroacetic acid (MCA) treatment on kidney sections. In proliferative glomerulonephritis (PGN), XLFbs were detected within the capillaries and extension beyond the mesangium was seen in severe PGN. The FRA within the mesangium of minimal or mild PGN was composed of the non-XLFb substance. The FRA within Bowman's space of most PGN had disappeared after MCA treatment, suggesting a non-XLFb substance. The presence of FRA within electron-dense deposits (EDD) suggested that FRA deposits are associated with immune-complex deposits in the glomeruli.

Acetates↗
PubMed1988

[In vitro susceptibilities of clinical isolates of Staphylococcus aureus].

In vitro susceptibilities of 350 strains of Staphylococcus aureus to ampicillin (ABPC), methicillin (DMPPC), cloxacillin (MCIPC), cefazolin (CEZ), cefmetazole (CMZ), cefmenoxime (CMX), latamoxef (LMOX) and 5 non-beta-lactam antimicrobial agents were determined according to the standard method of Japan Society of Chemotherapy. Frequencies of the appearance of resistant organisms (MIC greater than or equal to 12.5 micrograms/ml) to beta-lactam antibiotics were 45% for ABPC, 27% for DMPPC, 11% for MCIPC, 24% for CEZ, 15% for CMZ, 36% for CMX and 51% for LMOX. To non-beta-lactam antimicrobial agents, resistant strains appeared at 31% to gentamicin, 15% to amikacin, 0.6% to minocycline (MINO), 1% to norfloxacin (NFLX) and 65% to fosfomycin (FOM). More than 80% of DMPPC-resistant strains were also resistant to LMOX, CMX, ABPC, FOM, and CEZ, but most of those were susceptible to MINO and NFLX. Incidence of DMPPC-CEZ resistant S. aureus was 23% of the 350 strains tested. As stated above, multiply resistant strains of S. aureus are present throughout different hospitals in Okinawa.

Ampicillin↗