Superconducting fluctuation in the Hall conductivity: An estimation of skew-scattering lifetime in YBa2Cu3O7- delta.
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Journal Article↗
Biomedical subjects
Y Matsuda
Publications and source records attributed to Y Matsuda.
Inhibition of IgE-mediated histamine release by myosin light chain kinase inhibitors.
Wortmannin, a specific inhibitor of myosin light chain kinase (MLCK) blocked IgE mediated histamine release from rat basophilic leukemia cell (RBL-2H3) and human basophils dose-dependently. Its IC50 was 20 nM for RBL-2H3 cells and 30 nM for human basophils. There was complete inhibition at the concentration of 1 microM. Wortmannin inhibited partially the A23187 induced histamine release from RBL-2H3 cells (40% inhibition at 1 microM). This inhibition was not accompanied by any significant effect on cytosolic free calcium concentration [( Ca2+]i). KT5926, another MLCK inhibitor, inhibited histamine release comparably with wortmannin and blocked to some degree the increase of [Ca2+]i in RBL-2H3 cells. Thus, the phosphorylation of myosin seems to be involved in signal transduction through Fc epsilon RI.
Alkaloids↗
Wortmannin, a microbial product inhibitor of myosin light chain kinase.
We have found that a fungal strain, Talaromyces wortmannin KY12420, produces a potent inhibitor of smooth muscle myosin light chain kinase (MLCK). This active product, designated as MS-54, was isolated and purified from the culture broth of the fungus and identified as wortmannin. The inhibition of MLCK by wortmannin was prevented by a high concentration of ATP. The activity of the catalytic domain, which was disclosed by partial tryptic digestion, was also inhibited by wortmannin. These results suggest that wortmannin acts at or near to the catalytic site of the enzyme. It was shown clearly by kinetic analyses, preincubation studies, and dialysis experiments that the inhibitory action of wortmannin on MLCK was irreversible. Under the condition of preincubation for 3 min, 0.3 microM wortmannin inhibited the activity of MLCK, while 10 microM wortmannin had no effect on the activities of cAMP-dependent protein kinase, cGMP-dependent protein kinase, and calmodulin-dependent protein kinase II, and had little effect on protein kinase C activity. These data expressed clearly the marked selectivity of the compound for MLCK. Furthermore, wortmannin also inhibited both the phosphorylation of myosin light chain and the contraction in rat thoracic aorta stimulated with KCl, which indicates the effectiveness of the compound in the cellular level as an MLCK inhibitor.
Adenosine Triphosphate↗
Block of synapse formation between cerebral cortical neurons by a protein kinase inhibitor.
Synchronized Ca2+ transients in cultured hippocampal neurons reflect the pattern of underlying electrical activity. Here we demonstrate a similar synchronization of cerebral cortical neurons in culture, and show that this functional coupling is correlated to the appearance of morphologically identified synapses using electron microscopy. During screening of a series of drugs for inhibition of in vitro synaptogenesis, the continuous presence of a protein kinase inhibitor (K-252b) in the culture medium was found to block the synchronous firing and to decrease significantly the number of morphologically identifiable synapses. Since K-252b does not permeate the cell membrane, the results strongly suggest that phosphorylation of cell surface protein(s) by a K-252b sensitive-protein kinase is an essential process in synapse formation.
Animals↗
Effects of HS-142-1, a novel non-peptide ANP antagonist, on diuresis and natriuresis induced by acute volume expansion in anesthetized rats.
In this study we used HS-142-1, a novel non-peptide antagonist for the atrial natriuretic peptide (ANP) receptor, to clarify the possible physiological significance of ANP in acute hypervolemia. Substantial volume expansion in anesthetized rats induced a strong diuresis and natriuresis. These renal responses were significantly blocked by HS-142-1 at a dose of 3.0 mgkg-1 i.v. This observation suggests that ANP and its guanylyl cyclase-coupled receptor are, under the present conditions, physiologically involved that appears to be responsible for the renal responses in the volume homeostasis.
Animals↗
HS-142-1, a novel non-peptide ANP antagonist, blocks the cyclic GMP production elicited by natriuretic peptides in PC12 and NG108-15 cells.
HS-142-1 is a novel non-peptide antagonist for atrial natriuretic peptide (ANP) receptor. The effect of HS-142-1 on the cyclic GMP production elicited by natriuretic peptides in neuronal cell lines, PC12 and NG108-15 was examined. Natriuretic peptides such as ANP, brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP) enhanced cyclic GMP production in a dose-dependent manner. HS-142-1 inhibited cyclic GMP accumulation elicited by natriuretic peptides in a dose-dependent fashion in both cells. The results suggest that HS-142-1 will be an important tool for identification and understanding of the mechanisms by which natriuretic peptides act in nervous systems.
Animals↗
Self-setting hydroxyapatite cement: a novel skeletal drug-delivery system for antibiotics.
A novel approach using a self-setting hydroxyapatite (HAP) cement as a skeletal drug-delivery system has been proposed to solve the problem of delivering drugs to skeletal tissue at sufficiently high local concentrations for desirable therapeutic effects. HAP cements loaded with antibiotics can be formed in situ and can be used as bonding materials between bone and prostheses, as well as drug-release devices. The cement also possesses sufficient mechanical strength to be a potential bone grafting material. Using cephalexin and norfloxacin as model drugs, we observed continuous in vitro release profiles of these compounds from cement pellets loaded 0.9-4.8% by weight with one of the drugs. This drug-release pattern correlated well with the Higuchi model. This hydroxyapatite cement drug-delivery system can be applied in the treatment of osteomyelitis and infected compound fractures.
Anti-Bacterial Agents↗
Effect of geometric factors on hydration kinetics of theophylline anhydrate tablets.
The effect of tablet thickness on the hydration kinetics of types I and II theophylline anhydrate tablets at 95% relative humidity and 35 degrees C was studied with various kinetic equations. Samples of 1- and 2-cm-diameter tablets (1 g) were compressed at 1000 kg/cm2. Types I and II tablets expanded by 11-17% in volume during hydration to the monohydrate. The thickness expansion of all tablets exceeded the diameter expansion. After the hygroscopicity test, the final expansion ratio of type I tablets was more than that of type II tablets. The hydration kinetics analysis suggested that the hydration of theophylline anhydrate tablets proceeds as follows: Hydration of the 1-cm-diameter type I tablet followed the two-dimensional phase boundary equation, and that of the 1-cm-diameter type II tablet followed the three-dimensional phase boundary equation, but those of the 2-cm-diameter types I and II tablets followed the equation for two-dimensional growth of nuclei. The hydration kinetics of tablets does not depend on the nature of bulk powder but on geometrical factors (tablet thickness and porosity).
Chemical Phenomena↗
Detection and separation of some arginine amidases including tissue kallikrein from human seminal plasma.
A plasminogen/plasmin like substance (AHSAA-1), with affinity to lysine column was separated from DEAE-cellulose adsorbed human seminal plasma. Two forms of acidic arginine amidase with different affinities to LBTI (AHSAA-2) and aprotinin columns (AHSAA-3) were separated from the DEAE-cellulose adsorbed preparation and AHSAA-3 was identified as tissue kallikrein. Two basic arginine amidase preparations having affinity to LBTI (BHSAA-1) and aprotinin column were also separated from the CM-cellulose adsorbed human seminal plasma. Three basic arginine amidases with different molecular mass (BHSAA-2 to 4) were separated by Cellulofine GCL-2000 gel filtration from aprotinin adsorbed material and some of their properties were examined.
Amino Acid Sequence↗
An experience of cell sorting using samples isolated from paraffin-embedded tissue of neuroblastoma.
Flow cytometric DNA content analyses were performed on samples from 72 patients with neuroblastoma. Nuclear suspensions obtained from paraffin-embedded samples were prepared using the method described by Schutte et al. Determination of DNA ploidy was possible in 62 out of 72 patients. DNA diploidy was detected in 23 (37.1%) and DNA aneuploidy was found in 39 (62.9%) of these 62 patients. Cell sorting was performed on two peak areas of the DNA histogram of samples with aneuploidy. The sorted cells of the first peak area were composed of small round cells and were considered to be normal lymphocytes. The sorted cells of the second peak area were composed of relatively large cells with obvious nucleoli and were considered to be neuroblastoma cells. Thus, two cell components could be distinguished by cell sorting. It is concluded that cell sorting may be of benefit in giving detailed information about DNA histograms, even in samples obtained from paraffin-embedded tissue.
Cell Separation↗
Deficiency of X and Y chromosomal pairing at meiotic prophase in spermatocytes of sterile interspecific hybrids between laboratory mice (Mus domesticus) and Mus spretus.
The normal association between the X and Y chromosomes at metaphase I of meiosis, as seen in air-dried light microscope preparations of mouse spermatocytes, is frequently lacking in the spermatocytes of the sterile interspecific hybrid between the laboratory mouse strains C57BL/6 and Mus spretus. The purpose of this work is to determine whether the separate X and Y chromosomes in the hybrid are asynaptic, caused by failure to pair, or desynaptic, caused by precocious dissociation. Unpaired X-Y chromosomes were observed in air-dried preparations at diakinesis, just prior to metaphase I. Furthermore, immunocytology and electron microscopy studies of surface-spread pachytene spermatocytes indicate that the X and Y chromosomes frequently fail to initiate synapsis as judged by the failure to form a synaptonemal complex between the pairing regions of the X and Y chromosomes. Several additional chromosomal abnormalities were observed in the hybrid. These include fold-backs of the unpaired X or Y cores, associations between the autosome and sex chromosome cores, and autosomal univalents. The occurrence of abnormal autosomal and XY-autosomal associations was also correlated with cell degeneration during meiotic prophase. The primary breakdown in hybrid spermatogenesis occurs at metaphase I (MI), with the appearance of degenerated cells at late MI. In those cells, the X and Y are decondensed rather than condensed as they are in normal mouse MI spermatocytes. These results, in combination with the previous genetic analysis of spermatogenesis in hybrids and backcrosses with fertile female hybrids, suggest that the spermatogenic breakdown in the interspecific hybrid is primarily correlated with the failure of XY pairing at meiotic prophase, asynapsis, followed by the degeneration of spermatocytes at metaphase I. Secondarily, the failure of XY pairing can be accompanied by failure of autosomal pairing, which appears to involve an abnormal sex vesicle and degeneration at pachytene or diplotene.
Animals↗
Genetic mapping of two DNA markers, D16Ros1 and D16Ros2, flanking the mutation site in the chakragati mouse, a transgenic insertional mutant.
We present here the genetic mapping of two novel loci, D16Ros1 and D16Ros2, to mouse Chromosome (Chr) 16. The probes for these loci were genomic fragments isolated from the chakragati mouse, a behavioral mutant resulting from insertional mutagenesis during the course of making transgenic mice. D16Ros1 and D16Ros2 were first mapped by recombinant inbred (RI) strain analysis and subsequently by the analysis of 145 progeny of two interspecific backcrosses between Mus domesticus and Mus spretus. These progeny had been typed for the centromere and this allowed mapping of D16Ros1 and D16Ros2 relative to the centromere. The other markers included in this study were Prm-1, Gap43 and Sod-1. The genetic map generated spanned 47.5 cM from the centromere to Sod-1, the most distal marker mapped here. The linkage data presented here should prove useful in mapping other loci relative to the centromere of Chr 16.
Animals↗
Increase in nucleoside diphosphatase in rat brain striatum lesioned with kainic acid.
The activity of ammoniagenesis from guanine nucleotides was found to increase significantly in rat brain after infusion of kainic acid into the striatum. Among the enzymes involved in degrading guanine nucleotides, nucleoside diphosphatase was markedly increased in the lesioned striatum. The enzyme activity began to increase 2 days after the infusion, and reached the maximum on the 13th day, the level being 4 times as high as that of the intact contralateral region. The increased activity was due to Type L enzyme, judging from its substrate specificity. Puromycin and cycloheximide inhibited this increase, indicating that the increased activity resulted from an increase in the net synthesis of the enzyme. These findings suggest that Type L NDPase might play some important roles in gliosis after neuronal lesion.
Acid Anhydride Hydrolases↗
HS-142-1, a novel polysaccharide of microbial origin, specifically recognizes guanylyl cyclase-linked ANP receptor in rat glomeruli.
HS-142-1, a novel polysaccharide, of microbial origin had been characterized as a specific antagonist of guanylyl cyclase-linked atrial natriuretic peptide (ANP) receptors (ANP-GC receptor) in bovine adrenal cortex. The effect of HS-142-1 on ANP receptors of rat glomeruli were examined. HS-142-1 blocked rat ANP (r-ANP)-stimulated cGMP production in a concentration-dependent manner, although it caused only slight inhibition in the specific binding of [125I]-rANP to the glomeruli where only a small portion of the binding sites are coupled to guanylyl cyclase. HS-142-1 recognized the 135K ANP receptor which is thought to be ANP-GC receptors but did not recognized 60K receptor, guanylyl cyclase-free type from affinity cross-linking studies with glomerular membranes. These results indicate that HS-142-1 is a specific antagonist for the ANP-GC receptor in rat glomeruli, and that it will be a powerful tool for understanding the physiological roles of ANP in renal responses.
Affinity Labels↗
Location and character of the cellular enzyme that cleaves the hemagglutinin of a virulent avian influenza virus.
H.-D. Klenk, W. Garten, and R. Rott (1984, EMBO J. 3, 2911-2915) have reported that hemagglutinin (HA) cleavage of virulent avian influenza viruses occurs in later steps of its intracellular transport and that the cleavage enzyme is calcium dependent and has a neutral pH optimum. The precise intracellular location of the HA cleavage, however, has never been established. Furthermore, because Klenk et al. used the whole cell lysate to examine the cleavage activity and the amino acid sequencing of the cleaved product was not done, the identity of the cleavage enzyme remains to be established. We therefore attempted to systematically characterize the HA cleavage of the virulent avian virus A/tern/South Africa/61 (H5N3). Using an inhibitor of glycoprotein transport (Brefeldin A) and temporal markers of glycoprotein processing, we found that the endoprotease responsible for the HA cleavage acts after the acquisition of endo-N-acetylglucosaminidase H resistance but before the addition of galactose to the molecule, and thus is located in the medial and/or trans Golgi. This observation was directly confirmed by in vitro experiments using rat liver subcellular membrane fractions containing Golgi complex. A fraction rich in galactosyltransferase (a trans Golgi marker) demonstrated the highest HA cleavage activity. The endoprotease in this fraction cleaved only the HA of the virulent avian influenza virus but not that of an avirulent virus. Through amino-terminal sequencing of the HA2 produced by digestion with the endoprotease in the rat Golgi fraction, we established that HA cleavage by the protease occurs at the authentic site. Further studies using the rat Golgi fraction showed that the HA cleavage enzyme is calcium dependent and has a low pH (6.0) optimum. Thus, the pH optimum of the enzyme in the Golgi fraction differs from that in whole cell lysate reported previously.
Animals↗
A novel glycosignaling system: GQ1b-dependent neuritogenesis of human neuroblastoma cell line, GOTO, is closely associated with GQ1b-dependent ecto-type protein phosphorylation.
Previously, we reported that ganglioside GQ1b specifically promoted neuritogenesis of human neuroblastoma cells (GOTO), and also that is specifically stimulated the phosphorylation of several cell surface proteins on the same cells. To disclose the relationship between the two events, we examined them using a novel protein kinase inhibitor, K-252b, which is a derivative of K-252a and cannot pass through cell membrane. K-252b inhibited the GQ1b-dependent neuritogenesis as well as the GQ1b-stimulated phosphorylation. This suggests the direct coupling between the two cell events and the occurrence of a new biosignal transduction system.
Carbazoles↗
Action of habenular efferents on ventral tegmental area neurons studied in vitro.
Action of habenular efferents on neurons of the ventral tegmental area (VTA) was studied with a slice preparation that preserved the habenula (Hb) and the VTA together with the interconnecting fiber bundle, the fasciculus retroflexus (FR). In the VTA, two types of neurons, presumably corresponding to the dopaminergic and nondopaminergic neurons, were discerned on the basis of the electrophysiological properties. Of 52 VTA neurons sampled, 42 [with the mean resting membrane potential of 56 +/- 7 mV (mean +/- SD)] responded with excitatory postsynaptic potentials (EPSPs) to FR stimulation. The EPSPs were monosynaptic in nature and rather weak in effect in the sense that they rarely triggered spikes. No significant differences in latency, duration, and time to peak were noted between the EPSPs generated in different types of neurons. FR stimulation evoked inhibitory postsynaptic potentials (IPSPs) in only six neurons, their resting membrane potential being 51 +/- 4 mV. The IPSPs frequently showed a fluctuation in latency. FR stimulation also produced antidromic responses in a few VTA neurons, but their long latencies precluded the possibility that the VTA-Hb projections contributed to the FR-evoked orthodromic responses in the VTA. EPSPs evoked by FR stimulation could be suppressed by kynurenic acid (1 mM). The findings indicate that the efferents of the Hb primarily have an excitatory effect on VTA neurons of any type and that the excitation may be mediated by amino acid receptors.
Animals↗
An interspecific linkage map of mouse chromosome 15 positioned with respect to the centromere.
We have used an interspecific backcross between C57BL/6J and Mus spretus to derive a molecular genetic linkage map of chromosome 15 that includes 25 molecular markers and spans 93% of the estimated length of chromosome 15. Using a second interspecific backcross that was analyzed with a centromere-specific marker, we were also able to position our map with respect to the chromosome 15 centromere. This map provides molecular access to many discrete regions on chromosome 15, thus providing a framework for establishing relationships between cloned DNA markers and known mouse mutations and for identifying homologous genes in mice and humans that may be involved in disease.
Animals↗