Biomedical subjects

K Wada

Publications and source records attributed to K Wada.

At least 379 records · Page 21Linked to original sources

PubMed1996

[Clinical studies on vancomycin in the treatment of MRSA infection].

We evaluated the effectiveness and safety of vancomycin (VCM) alone and in combination with beta-lactam antibiotics in the treatment of MRSA infections, and obtained the following results: 1. Effectiveness. (1) In cases of MRSA infections alone, the improvement rate was 71.4% (5/7 patients) with VCM alone and 77.8% (35/45) with VCM in combination with beta-lactam antibiotics. (2) In cases of polymicrobial infections, few cases were treated with VCM alone, but the improvement rate in combination use with beta-lactam antibiotics was 71.8% (28/39). 2. Bacteriological effect. (1) In cases of single infection with MRSA, the rate of bacterial eradication was 71.4% (5/7) with VCM alone and 68.2% (30/44) with VCM in combination with beta-lactam antibiotics. (2) In cases of polymicrobial infections, few cases were treated with VCM alone, but the rate of bacterial eradication in combination use with be ta-lactam antibiotics was 63.2% (24/38) against MRSA and 31.6% (12/38) against polymicrobial agents including MRSA. 3. Safety. Occurrences of adverse reactions and abnormal laboratory test values when VCM was used alone or when it is used in combination with another drug were about the same in these uses. As a whole, advance reactions were observed in 16 patients (9.5%). Main adverse reactions were whole body redness, drug eruption, and rash etc. Abnormal laboratory test values were observed mainly in hepatic functions, and renal functions. 4. VCM concentrations in blood was determined in 38 patients. Doses of 0.5 g and 1.0 g of VCM was administered by intravenous drip infusion over a period of 1 to 2 hours, and mean blood concentrations 1 to 2 hours after the completion of drip infusion were 25.4 micrograms/ml and 14.4 micrograms/ml, respectively. 5. Synergic effects between VCM and other antibiotics tested were observed in FIC index against all of the six MRSA strains isolated from six patients, and the clinical effects of improvement or better were obtained against five of them.

Adolescent↗

PubMed1995

Protective effect of cystathionine on acute gastric mucosal injury induced by ischemia-reperfusion in rats.

We studied the protective effect of cystathionine on acute gastric mucosal injury induced by ischemia-reperfusion in rats. Under pentobarbital anesthesia, the celiac artery was clamped for 30 min and reperfused. Sixty minutes after the reperfusion, the total area of erosions and thiobarbituric acid-reactive substances in the stomach, as an index of lipid peroxidation, were measured and compared between control and cystathionine-treated groups. Intraperitoneal administration of cystathionine (1-20 mg/kg) 10 min before the ischemia significantly reduced both the total area of erosions and the level of thiobarbituric acid-reactive substances. When cystathionine (10 mg/kg) was administered orally, the significant reductions in the total area of erosions and level of thiobarbituric acid-reactive substances were also observed. There was a good correlation between the total area of erosions and the level of thiobarbituric acid-reactive substances. Cystathionine did not affect blood flow during ischemia-reperfusion. These results indicate that the protective effect of cystathionine on acute gastric mucosal injury induced by ischemia-reperfusion may be due to the scavenging action against superoxide radicals in vivo.

Animals↗

PubMed1995

Cloning of boar SPMI gene which is expressed specifically in seminal vesicle and codes for a sperm motility inhibitor protein.

Boar semen contains a seminal plasma motility inhibitor (SPMI) that blocks the motility of demembranated-reactivated spermatozoa as well as of intact spermatozoa. In this paper, we describe the primary structure of SPMI, the coding of boar SPMI cDNA gene and its expression in various porcine tissues. Nucleotide sequence analysis of the 645-bp SPMI cDNA predicts a coded polypeptide of 137 amino acid residues which includes a 21-residue signal peptide and a 116-residue secreted protein. The amino acid sequence of SPMI was found to be highly homologous to AQN-3, a member of spermadhesin family proteins of boar that bind to spermatozoa. Expression of the boar SPMI gene detected by Northern blot analysis revealed that its expression is very abundant in seminal vesicles and specific to this tissue.

Amino Acid Sequence↗

PubMed1995

Nitric oxide inhibition of the depolarization-evoked glutamate release from synaptosomes of rat cerebellum.

Effects of nitric oxide (NO) on release of amino acid transmitter were investigated by superfusion of synaptosomes prepared from rat cerebellum. After constant basal levels of amino acid release were obtained, exposure to a depolarizing concentration of KCl (30 mM) evoked 4.05-, 2.18- and 3.00-fold increases in release of glutamic acid (Glu), aspartic acid (Asp) and gamma-aminobutyric acid (GABA) from synaptosomes. The perfusion with NO-donors inhibited the evoked increases in release of Glu and Asp in a concentration-dependent manner, but not that in GABA release. A membrane-permeable analog of cyclic GMP, but not that of cyclic AMP, caused a similar reduction in the evoked release. The concentration of nitroprusside to increase cyclic GMP levels corresponded to that of nitroprusside to reduce the evoked release. These data suggest that NO may directly act upon the nerve terminals to inhibit release of excitatory amino acid transmitters.

Animals↗

PubMed1995

Mapping of the gracile axonal dystrophy (gad) gene to a region between D5Mit197 and D5Mit113 on proximal mouse chromosome 5.

The gracile axonal dystrophy (gad) mouse, which shows hereditary sensory ataxia and motor paresis, has been morphologically characterized by the dying back type of axonal degeneration in the nerve terminals of dorsal root ganglion cells and motor neurons. In the present study, using an intraspecific backcross between gad and C57BL/6J mice, the gracile axonal dystrophy (gad) gene was mapped to a region between D5Mit197 and D5Mit113. Estimated distances between gad and D5Mit197 and between gad and D5Mit113 are 0.4 +/- 0.3 and 5.0 +/- 1.0 cM, respectively. The gene order was defined: centromere-D5Mit81-D5Mit233-D5Mit184/D5Mit254- D5Mit256-D5Mit197-gad-D5Mit113-D5Mit7. The mouse map location of the gad locus appears to be in a region homologous to human 4p15-p16. Our present data suggest that the nearest flanking marker D5Mit197 provides a useful anchor for the isolation of the gad gene in a yeast artificial chromosome contig.

Alleles↗

PubMed1995

Purification, cloning, and expression of murine uridine phosphorylase.

Uridine phosphorylase was purified 10,300-fold from tumors of the murine colorectal adenocarcinoma cell line, Colon-26. Degenerate DNA probes were synthesized corresponding to partial amino acid sequences and used to screen a Colon-26 cDNA library. A cDNA clone of 1327 base pairs that contains a 5' untranslated region, a coding region of 933 base pairs, and a 3' nontranslated region with a polyadenylated tail was identified. The cDNA was confirmed to be uridine phosphorylase by 1) sequence comparison to uridine phosphorylase of Escherichia coli, 2) substrate specificity studies with recombinant protein expressed in COS-7 cells that demonstrated relatively high enzyme activity with uridine as substrate compared low levels when thymidine was used, and 3) inhibition of enzyme activity by the competitive inhibitor 2,2'-anhydro-5-ethyluridine. Northern blot analysis using the cDNA as a probe, demonstrated high levels of mRNA expression in Colon-26. Expression was low in NIH3T3 cells, but high in DMBA-3 and PH-1 cells, which are NIH3T3-derived cells that have been transformed with mutated murine Ha-ras and viral Ha-ras, respectively. Expression of uridine phosphorylase mRNA in these cell lines was further enhanced by treating the cells with the inflammatory cytokines, tumor necrosis factor-alpha, interleukin 1 alpha, and interferon gamma.

Adenocarcinoma↗

PubMed1995

Molecular cloning of two glutamate transporter subtypes from mouse brain.

The physiological action of glutamate is terminated by diffusional processes with its subsequent removal by high-affinity transport systems localized to glial and/or neuronal elements. Several cDNAs encoding glutamate transporters have been isolated from mammalian tissues. Here, we screened a cDNA library derived from mouse cerebellum and isolated the two glutamate transporters, termed MGLT1 and MEAAC1. The MGLT1 and MEAAC1 cDNAs encode proteins of 572 and 523 amino acids, respectively. MGLT1 has 93.9% amino acid sequence identity with the rat GLT1 and MEAAC1 has 89.3% identity with the rabbit EAAC1. MEAAC1 mRNA was expressed in brain, lung, kidney and skeletal muscle, whereas expression of MGLT1 was restricted to brain.

ATP-Binding Cassette Transporters↗

PubMed1995

Sustained activation of blood coagulation in patients with cerebral thrombosis.

Recent progress in the measurements of the hemostatic markers enables us to assess the detailed profiles of hemostatic activation in various diseases. To evaluate the degree of hemostatic system activation in patients with cerebral thrombosis, detailed coagulation studies were performed in 28 patients with acute-phase cerebral thrombosis and in 36 with chronic-phase cerebral thrombosis, together with 6 with chronic-phase cerebral hemorrhage and 37 age-matched healthy volunteers. In both acute-phase and chronic-phase cerebral thrombosis, plasma levels of thrombin-antithrombin III complex, plasmin-alpha 2-plasmin inhibitor complex and D-dimer were significantly higher, and antithrombin III and protein C were significantly lower than those in the normal group. Plasma fibrinogen concentration was significantly higher in chronic-phase cerebral thrombosis than that in chronic-phase cerebral hemorrhage. No significant difference was found in these variables between acute-phase and chronic-phase cerebral thrombosis. In addition, there was no difference in these parameters between chronic phase cerebral hemorrhage and normal subjects. These findings indicate that a sustained activation of coagulation and fibrinolysis is present in cerebral thrombosis, and it might contribute to the pathogenesis of cerebral thrombosis.

Acute Disease↗

PubMed1995

Ligand binding domain of the human endothelin-B subtype receptor.

We have employed both protein chemical and molecular biological approaches to determine the ligand binding domain of the endothelin-B subtype (ETB) receptor. The human ETB receptor purified from human placenta by using affinity chromatography was cross-linked with 125I-labeled endothelin-1 (ET-1) and then incubated in the presence of trypsin or thermolysin under nondenaturing conditions. The N-terminal amino acid sequence of the radiolabeled polypeptide encompassed approximately 115 amino acid residues starting from Ile85 of the human ETB receptor. This was confirmed by experiments in which the binding activity of endothelin-1 to various chimeric endothelin receptors was monitored in the presence and absence of competitive endothelin receptor antagonists such as BQ-123 and bosentan. The region from Ile138 to Ile197 (60 amino acid residues) of the ETB receptor was found to interact with both antagonists. Therefore, this sequence was determined to be the ligand binding domain. In addition, we found that part of the N-terminal domain in close proximity to the first transmembrane region was required for the ligand binding activity of the ETB receptor, and the 12 amino acid residues from Ser390 to Leu401 at the proximal cytoplasmic tail are perhaps necessary to maintain the ligand binding site in active form. The cysteine rich region from residue 400 to residue 403 in the C-terminus of the ETB receptor is involved in coupling of the guanine nucleotide-binding regulatory protein for ET-1-induced signal transduction.

Amino Acid Sequence↗

PubMed1995

Induction of cyclooxygenase protein and stimulation of prostaglandin E2 release by epidermal growth factor in cultured guinea pig gastric mucous cells.

The present study was undertaken to investigate whether epidermal growth factor (EGF) could stimulate prostaglandin E2 release, and if so, by what mechanism EGF would exert such an effect in gastric mucosal cells. In cultured guinea pig gastric mucous cells, EGF dose-dependently stimulated prostaglandin E2 release, with maximal stimulation observed at 10 ng/ml. EGF stimulated an increase in cyclooxygenase activity, which was reduced by protein synthesis inhibitor, actinomycin D, and cycloheximide. EGF also stimulated the enzyme protein synthesis estimated by Western blot analysis, whereas EGF did not stimulate phospholipase A2 activity. These results suggest that such an effect of EGF of de novo synthesis of cyclooxygenase protein and prostaglandin E2 release may be involved at least in part in the mechanism of EGF-induced local regulation of gastric mucosal integrity.

Animals↗

PubMed1995

Differential mechanism of retention of Cu-pyruvaldehyde-bis(N4-methylthiosemicarbazone) (Cu-PTSM) by brain and tumor: a novel radiopharmaceutical for positron emission tomography imaging.

The reductive retention of 62Cu-PTSM was comparatively studied in the brain and Ehrlich ascites tumor cells by electron spin resonance spectrometry and nonradioactive Cu-PTSM. In the brain, only the mitochondrial fraction showed the ability to reduce Cu-PTSM, and the other subcellular fractions did not. In contrast, the cytosolic fraction of Ehrlich ascites tumor cells was the specific site of Cu-PTSM reduction. It was therefore considered that the retention of Cu-PTSM in the brain is closely related to mitochondrial reduction, most probably involving the mitochondrial electron transport system.

Animals↗

PubMed1995

Direct measurement of superoxide-dependent chemiluminescence from rat skin following UV-dependent fluoroquinolone-induced dermatitis.

Fluoroquinolones are widely used for the treatment of bacterial infection. However, some members of the group cause UV-dependent dermatitis. Therefore, animal models are required to screen and predict if a derivative is likely to cause photodermatitis. Under anaesthesia, the hair on the dorsal side of rats was shaved, then a fluoroquinolone derivative, Y-26611 or ofloxacin was administered subcutaneously (SC) followed by irradiation of a 3 cm diameter circular area of the skin with UV-B(ultraviolet-B) for 45 min. Peak photodermatitis was observed 24 h after irradiation in Y-2611-treated skin. Leucocyte infiltration into the skin, mostly polymorphonuclear leucocytes, was verified by histological techniques. O2.- radical generated by activated leucocytes was detected directly from the skin by SC application of a sensitive O2.- -dependent luminescence reagent, MCLA. O2.- -dependent photon emission (chemiluminescence) from the skin was amplified by phorbol myristate acetate and was markedly suppressed by superoxide dismutase. This is the first report of direct detection of chemiluminescence from the skin of a living animal.

4-Quinolones↗

PubMed1995

Relationship between morphological classification of the degree of maturation and the ploidy of micromegakaryocytes in myelodysplastic syndrome patients.

To clarify the biological behavior of micromegakaryocytes in myelodysplastic syndrome (MDS), the relationship between the morphological classification and the ploidy of megakaryocytes was studied in bone marrow aspirates obtained from patients with MDS and from normal controls. The morphology was determined according to Feinendegen's classification, which is considered to reflect megakaryocytic maturation, and the ploidy was determined by microcytofluorometry, using 4',6-diamidino-2-phenylindole (DAPI) staining after the removal of Wright-Giemsa stain. Most micromegakaryocytes (i.e., megakaryocytes < 20 microns in diameter) in MDS were morphologically mature, as were those in the normal controls. The peak micromegakaryocytic ploidy was 4N or 8N, whereas that of the megakaryocytes in normal controls was 16N. These findings indicated that the micromegakaryocytes in MDS were morphologically mature but had impaired polyploidization.

Adult↗

PubMed1995

Correlation between the induction of a gene for delta 1-pyrroline-5-carboxylate synthetase and the accumulation of proline in Arabidopsis thaliana under osmotic stress.

The isolation and characterization is reported of a cDNA for delta 1-pyrroline-5-carboxylate (P5C) synthetase (cAtP5CS), an enzyme involved in the biosynthesis of proline, from a cDNA library prepared from a dehydrated rosette plant of Arabidopsis thaliana. Southern blot analysis suggested that only one copy of the corresponding gene (AtP5CS) is present in A. thaliana. The deduced amino acid sequence of the P5CS protein (AtP5CS) from A. thaliana exhibited 74% homology to that of the P5CS from Vigna aconitifolia. Northern blot analysis revealed that the gene for P5CS was induced by dehydration, high salt and treatment with ABA, while it was not induced by heat or cold treatment. Moreover, the simultaneous accumulation of proline was observed as a result of the former treatments in A. thaliana. A cDNA for P5C reductase (cAtP5CR) was also isolated from A. thaliana and Northern blot analysis was performed. The AtP5CR gene was not induced to a significant extent by dehydration or high-salt stress. These observations suggest that the AtP5CS gene plays a principal role in the biosynthesis of proline in A. thaliana under osmotic stress.

1-Pyrroline-5-Carboxylate Dehydrogenase↗

PubMed1995

Functional comparison of D-serine and glycine in rodents: the effect on cloned NMDA receptors and the extracellular concentration.

We compared the activity of free D-Ser on the potentiation of cloned NMDA receptors with that of Gly by using a Xenopus oocyte expression system. The extracellular concentration of free D-Ser and Gly was further studied by means of microdialysis. The ED50 values of D-Ser were three to four times lower than those of Gly in any combination of epsilon 1, epsilon 2, epsilon 3, or epsilon 4 and zeta 1. Site-directed mutagenesis of zeta 1 subunits revealed that some aromatic residues necessary for the action of Gly affected the ED50 value of D-Ser. This result showed that the residues play crucial roles in the action of D-Ser. In vivo microdialysis of rodent brain revealed that the extracellular concentration of free D-Ser in the frontal cortex (6.5 microM) was high enough to saturate the Gly site on the NMDA receptor, but that in the cerebellum was not. These findings suggest that D-Ser is a candidate of the endogenous potentiator of the NMDA receptor in the rodent frontal cortex.

Animals↗

PubMed1995

Nitric oxide regulates substance P release from rat spinal cord synaptosomes.

In order to determine whether nitric oxide (NO) acts directly upon nerve terminals to regulate the synaptic transmission at the level of spinal cord, effects of NO-donors on release of substance P (SP) and glutamic acid (Glu) were investigated by superfusion of synaptosomes prepared from the rat spinal cord. Basal levels of endogenous SP and Glu release were 5.99 +/- 2.50 fmol/min/mg of protein and 26.2 +/- 4.8 pmol/min/mg of protein, respectively. Exposure to a depolarizing concentration of KCI evoked 2.7- and 3.8-fold increases in SP and Glu release in a calcium-dependent manner, respectively. Sodium nitroprusside (NP) caused a reduction in the depolarization-evoked overflow of SP in a concentration-dependent manner without affecting its basal release, although it failed to affect either basal or evoked release of Glu. The reduction in SP overflow was also observed by the perfusion with S-nitroso-N-acetyl-penicillamine or membrane-permeable cyclic GMP, but not with cyclic AMP. NP caused the concentration-dependent increases in cyclic GMP levels in synaptosomes. Together with reports that excitatory amino acids stimulate NO synthase and release NO in the spinal cord, these data suggest that there may be an interaction between nerve terminals containing Glu and SP, and that NO may directly participate in the regulation of synaptic transmission in SP-containing nerve terminals, which may be mediated through the activation of guanylate cyclase and the increase in cyclic GMP levels.

Amino Acids↗

PubMed1995

Glycosylated human recombinant interleukin-1 alpha, neo interleukin-1 alpha, with D-mannose dimer exhibits selective activities in vivo.

To investigate the effect of carbohydrate-introduction on IL-1 activity, especially in vivo, and to develop IL-1 with less deleterious effects, recombinant human IL-1 alpha was coupled with mannose dimer, alpha-D-Man-1-6-D-Man [Man2 alpha(1-6)] by an acyl azide method. Previous studies demonstrated that the glycosylated IL-1 exhibited reduced activities compared with original IL-1 in all the experiments performed in vitro. In this study, we investigated the in vivo activities of Man2 alpha(1-6)-conjugated IL-1 alpha. The glycosylated IL-1 alpha exhibited very low pyrogenic activity and alpha 1-acid glycoprotein induction compared with untreated IL-1 alpha. Untreated IL-1 alpha increased the serum level of IL-6, but the glycosylated IL-1 alpha did not. However, the glycosylated IL-1 alpha possessed the same potency as untreated IL-1 alpha in reduction of serum levels of glucose and triglyceride and in recovery of peripheral white blood cells in 5-fluorouracil-treated mice. Therefore, glycosylation of IL-1 appeared to be useful for the development of neoIL-1 with selective activity in vivo.

Animals↗

PubMed1995

Stabilization of lysozyme against irreversible inactivation by suppression of chemical reactions.

The effects of additives on the nonenzymatic deamidation of an Asn residue in a peptide and racemization of Asp and/or Asn in lysozyme were investigated at pH 6 and 100 degrees C. These chemical reactions were accelerated by the addition of phosphate ions. Several salts suppressed the deamidation in the presence of phosphate ions, while the salts did not affect the deamidation in the absence of phosphate ion at pH 6 and 100 degrees C. The results indicated that the effect of the salts was due to the suppression of phosphate catalysis. On the other hand, trifluoroethanol (TFE), which induces the conversion of random coiled polypeptides to secondary structured ones, dramatically suppressed the deamidation of an Asn residue in a peptide. The rate of deamidation in the presence of TFE was comparable to that of asparagine (free amino acid), which was very slowly deamidated. Because TFE could not suppress the deamidation of free asparagine, the suppression of the deamidation of an Asn residue in a peptide was attributed to suppression of the catalysis by the peptide bond in the carboxyl terminus. Since the inactivation of lysozyme was caused by multiple chemical reactions such as the deamidation and racemization, it was expected that the inactivation of lysozyme could be prevented by the addition of salts or TFE. Thus, it was confirmed that salts and TFE suppressed the lysozyme inactivation at pH 6 and 100 degrees C.

Amides↗