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Biomedical subjects

Y Matsuda

Publications and source records attributed to Y Matsuda.

At least 19 recordsLinked to original sources
PubMed1992

Stable expression of natriuretic peptide receptors: effects of HS-142-1, a non-peptide ANP antagonist.

We established clonal cell lines stably expressing each of two subtypes of membrane bound guanylate cyclases (GC-A and GC-B), which are known as natriuretic peptide receptors. Using these cell lines, we showed that GC-A is an ANP/BNP receptor, whereas GC-B is a specific receptor for CNP. Effects of HS-142-1, a novel non-peptide ANP antagonist, on GC-A and GC-B were examined by using these cells. In cells expressing either GC-A or GC-B, HS-142-1 inhibited cGMP production elicited by ANP or CNP with IC50 values of 1.8 micrograms/ml and 1.5 micrograms/ml, respectively, and also competitively blocked specific binding of the natriuretic peptides with IC50 values of 2.2 micrograms/ml and 3.3 micrograms/ml, respectively. These results indicate that HS-142-1 is a potent antagonist of CNP as well as ANP. We also showed that CNP suppressed the growth of cells expressing GC-B by 22% and that HS-142-1 blocked the antiproliferative action of CNP.

Animals↗
PubMed1992

Enhancing effect of wortmannin on muscarinic stimulation of phospholipase D in rat pheochromocytoma PC12 cells.

Wortmannin, a specific inhibitor of myosin light chain kinase (MLCK), enhanced carbachol-induced formation of [3H]phosphatidylethanol ([3H]PEt), a marker of phospholipase D (PLD) activity, in [3H]palmitic acid-labeled PC12 cells. The apparent EC50 value was 1.5 microM, and the effect was maximal at 3 microM and slightly attenuated at higher concentration. Wortmannin alone had no significant effect on [3H]PEt formation. The enhancing effect of wortmannin was observed at the initial increasing phase of [3H]PEt formation but not at the subsequent plateau phase. Wortmannin enhanced also phorbol ester-induced PLD activation. Although the precise mechanism remains to be clarified, these results suggest that MLCK may be involved in PLD regulation in PC12 cells.

Androstadienes↗
PubMed1992

Prevention of autoimmune insulitis in nonobese diabetic mice by expression of major histocompatibility complex class I Ld molecules.

Nonobese diabetic (NOD) mice spontaneously develop a T-cell-mediated autoimmune disease that is similar in many respects to insulin-dependent diabetes mellitus in humans. NOD mice were shown to express major histocompatibility complex class I Kd and Db antigens. To examine the possible involvement of major histocompatibility complex class I molecules in the development of autoimmune insulitis, we attempted to express a different type of class I molecule in NOD mice by crossing C57BL/6 mice transgenic for the class I Ld gene with NOD mice. The backcross progeny expressed the Ld antigen on the peripheral blood lymphocytes at a level comparable with that of the BALB/c mice. The cell surface expression of endogenous class I and class II antigens on the peripheral blood lymphocytes was not affected. Analysis of these mice revealed that the expression of the class I Ld antigen significantly reduced the incidence of insulitis at 20 weeks of age. In situ hybridization of a biotinylated probe on mouse chromosomes showed that the Ld transgene was located in the E area of chromosome 6 with which no genetic linkage to insulin-dependent diabetes mellitus was demonstrated. These results suggest that the NOD-type class I molecules are involved in the development of insulitis in NOD mice.

Animals↗
PubMed1992

Two thrombin-activated Ca2+ channels in human platelets.

The regulation of extracellular Ca2+ entry into fura-2-loaded human platelets was examined following stimulation with thrombin. In the presence of external Ca2+, stimulation of platelets with thrombin resulted in a rapid increase, followed by a plateau, in intracellular Ca2+ concentration ([Ca2+]i). Pretreatment with wortmannin, a specific inhibitor of myosin light chain kinase, suppressed only the plateau phase and had no effect on the initial rapid increase in [Ca2+]i. In Ca(2+)-free EGTA buffer, thrombin induced a transient and relatively small increase in [Ca2+]i caused by Ca2+ release from internal stores. When Ca2+ was added subsequently to the Ca(2+)-free medium within 10 min after thrombin activation, a marked increase in [Ca2+]i was seen, reflecting thrombin-stimulated external Ca2+ entry. With the Ca(2+)-free medium, wortmannin did not affect either the Ca2+ mobilization from the internal stores or the rapid external Ca2+ entry at early time points (within 5 s) after thrombin stimulation, whereas it significantly inhibited Ca2+ entry when Ca2+ was added later (at 3 min). Wortmannin inhibition of this late Ca2+ entry and that of 20-kDa myosin light chain phosphorylation after thrombin stimulation were dose- and preincubation time-dependent and correlated well with each other. These results suggest that two different channels are responsible for Ca2+ entry in human platelets at the early and late phases of thrombin stimulation and that the channel responsible for the late phase of Ca2+ entry may be activated by a mechanism involving myosin light chain kinase.

Androstadienes↗
PubMed1992

The ES-242s, novel N-methyl-D-aspartate antagonists of microbial origin, interact with both the neurotransmitter recognition site and the ion channel domain.

ES-242-1 approximately 5 are novel microbial bioxanthracenes which do not contain nitrogen. The ES-242s inhibited the binding of [3H]TCP and [3H]CGS19755 to the N-methyl-D-aspartate (NMDA) receptor complex. They had no effect on the binding of the specific ligands for the non-NMDA receptor. The biochemical and pharmacological properties of ES-242-1 were fully examined since it is the most potent of the five compounds. ES-242-1 is highly specific for the NMDA receptor; it has no effect on other receptors. Kinetic analyses indicated that ES-242-1 inhibited the binding of [3H]TCP and [3H]CGS19755 in a competitive manner, respectively, suggesting that ES-242-1 interacts with both the transmitter recognition site and the channel domain. ES-242-1 selectively inhibited NMDA-induced Ca2+ influx in primary cultures of mouse hippocampal neurons. ES-242-1 also specifically blocked the increase in cyclic GMP accumulation induced by NMDA or L-glutamate in rat cerebellar slices. In a concentration range of 0.1-1.0 microM, ES-242-1 was as potent as MK-801 in preventing glutamate-induced neurotoxicity in primary cultures of mouse hippocampal neurons. These results show that ES-242-1 is a potent and specific antagonist for the NMDA receptor. The antagonistic properties of the ES-242s appear to be due to a novel mechanism of action at the NMDA receptor.

Animals↗
PubMed1992

Inhibition of Ca(2+)-dependent catecholamine release by myosin light chain kinase inhibitor, wortmannin, in adrenal chromaffin cells.

To elucidate the possible involvement of myosin light chain kinase (MLCK) in the mechanism of exocytosis, we studied effects of MLCK inhibitor, wortmannin, on the secretory function of bovine adrenal chromaffin cells. Preincubation of chromaffin cells with wortmannin inhibited both acetylcholine- and high K(+)-evoked catecholamine (CA) release. The IC50 for high K(+)-evoked CA release was 1 microM. When the cells were permeabilized with digitonin after wortmannin preincubation, Ca(2+)-dependent exocytosis was inhibited in a dose-dependent manner (IC50, 1 microM). These findings suggest the implication of MLCK in the Ca(2+)-triggered process in the machinery of exocytosis.

Acetylcholine↗
PubMed1992

Primary structure and expression of a gamete lytic enzyme in Chlamydomonas reinhardtii: similarity of functional domains to matrix metalloproteases.

A gamete lytic enzyme (GLE) of Chlamydomonas reinhardtii is a zinc metalloprotease and mediates digestion of the cell walls of the two mating-type gametes during mating as a necessary prelude to cell fusion. The nucleotide sequence analysis of a cDNA revealed that GLE is synthesized in a preproenzyme form, a 638-amino acid polypeptide (Mr, 69,824) with a 28-amino acid signal peptide, a 155-amino acid propolypeptide, and a 455-amino acid mature polypeptide (Mr, 49,633). A potential site for autocatalytic activation was contained within the propolypeptide and a zinc binding site found within the mature polypeptide; both sites were highly homologous to those in mammalian collagenase. A putative calcium binding site was present in the near C-terminal region of the mature GLE. Both propolypeptide and mature polypeptide had potential sites for asparagine-linked glycosylation, and the Arg-(Pro)3 and Arg-(Pro)2 motifs, which are known to exist in hydroxyproline-rich glycoproteins of the Chlamydomonas cell wall. Northern blot analysis revealed that steady-state levels of the 2.4-kilobase GLE mRNA increased during growth and mitotic cell division in the vegetative cell cycle and also increased markedly during gametogenesis under nitrogen-starved conditions.

Amino Acid Sequence↗
PubMed1992

HS-142-1, a novel nonpeptide atrial natriuretic peptide (ANP) antagonist, blocks ANP-induced renal responses through a specific interaction with guanylyl cyclase-linked receptors.

HS-142-1, a novel microbial product, blocked 125I-labeled rat atrial natriuretic peptide (rANP) (= ANF(99-126)) binding to bovine adrenocortical membranes, where guanylyl cyclase-containing receptors are predominantly expressed. However, HS-142-1 only slightly inhibited [125I]rANP binding to bovine lung membranes where only a small portion of binding sites are coupled to guanylyl cyclase. Further, HS-142-1 only recognized the 135 kDa ANP receptor, which is considered to be the guanylyl cyclase-containing receptor based on the results obtained in affinity cross-linking studies with bovine adrenocortical and lung membranes. Under identical conditions, Atriopeptin I selectively recognized guanylyl cyclase-free receptors both in binding and affinity cross-linking experiments. When injected intravenously (1 mg/kg) to anesthetized rats, HS-142-1 abolished ANP-induced diuresis and natriuresis. These results suggest that HS-142-1 works in vivo through a specific interaction with the ANP functional receptor, and that HS-142-1 will be a powerful tool for understanding the physiological roles of ANP in distinction from its pharmacological effects.

Adrenal Glands↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗