Search PubMed⌕ Search

Biomedical subjects

M Terasawa

Publications and source records attributed to M Terasawa.

At least 55 records · Page 3Linked to original sources
PubMed1991

Identification and characterization of protein kinase C-related enzymes in frog retina.

We isolated two types of protein kinase C-related enzymes (fPKC) in frog (Rana catesbeiana) retina. Three sequential steps of column chromatography of DEAE-cellulose, butyl-Toyopearl, and hydroxylapatite were carried out and resulted in the separation of two types of distinct Ca2+/phospholipid-dependent protein kinase activities. These proteins reacted with antibodies raised against synthetic peptides based on the predicted amino acid sequences of rat protein kinase C delta or zeta subspecies, and showed molecular masses of 90 and 75 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, respectively. Immunocytochemical analysis of 90 and 75K fPKC in frog retina revealed that the 75K fPKC was localized in the outer segment of cone cells and in the microvillar projections of Müller cells. These results suggested that fPKCs play differential roles on the photosignal transduction in frog retina.

Amino Acid Sequence↗
PubMed1991

Differential localization of protein kinase C isozymes in retinal neurons.

We report the immunohistochemical localization of protein kinase C isozymes (types I, II, and III) in the rabbit retina using the monospecific monoclonal antibodies MC-1a, MC-2a, and MC-3a. Using immunoblot analysis of partially purified protein kinase C preparations of rabbit retina, types II and III isozymes alone were detected. The activity of type III was the stronger. By light microscopic immunohistochemical analysis, retinal neurons were negative for type I and positive for type II and type III isozymes. Type II was more diffusely distributed through the retinal layers, but was distinctive in ganglion cells, bipolar cells, and outer segments. The immunoreactivity was stronger for type III isozyme, and it was observed in mop (rod) bipolar cells and amacrine cells. By using immunoelectron microscopy, the cytoplasm of the cell body, the axon, and dendrites of the mop bipolar cells were strongly immunoreactive for type III. The so-called rod bipolar cells were for the first time seen to form synapses with rod photoreceptor cells. These differential localizations of respective isozymes in retinal neurons suggest that each isozyme has a different site of function in each neuron.

Animals↗
PubMed1991

Ca2+/calmodulin-dependent protein phosphorylation associated with the cytoskeleton of quiescent rat fibroblast (3Y1) cells.

Endogenous phosphorylation of the crude membrane fraction of cultured 3Y1 fibroblast cells was enhanced by the addition of Ca2+/calmodulin. Both Ca2+/calmodulin-dependent protein kinase activity and its substrate were present in a cytoskeletal fraction, obtained as a pellet after washing of the membrane fraction with 2 mM EGTA, 0.6 M NaCl, and 1% Triton X-100. The phosphorylatable protein in the Triton X-insoluble fraction was identified by immunoblotting as vimentin. This endogenous phosphorylation induced by calmodulin was inhibited by the addition of KN-62, a specific Ca2+/calmodulin-dependent protein kinase II inhibitor, in a dose-dependent manner. However, phosphorylation of the 59 kDa protein (vimentin) in this fraction was not stimulated by adding both phosphatidyl serine and cAMP, thereby suggesting the absence of protein kinase C or of cAMP-dependent protein kinase in this fraction. The protein kinase associated with the Triton X-insoluble fraction phosphorylated the Ca2+/calmodulin-dependent protein kinase II-specific site of synapsin I from the bovine cortex. Two-dimensional phosphopeptide maps of vimentin indicated that a major phosphopeptide phosphorylated by the endogenous calmodulin-dependent kinase also appears to be the same as a major phosphopeptide phosphorylated by the exogenous Ca2+/calmodulin-dependent protein kinase II. Our results suggest that cytoskeleton-associated Ca2+/calmodulin-dependent protein kinase II regulates dynamic cellular functions through the phosphorylation of cytoskeletal elements in non-neural cells.

Animals↗
PubMed1991

Identification of plasmid partition function in coryneform bacteria.

We have identified and characterized a partition function that is required for stable maintenance of plasmids in the coryneform bacteria Brevibacterium flavum MJ233 and Corynebacterium glutamicum ATCC 31831. This function is localized to a HindIII-NspV fragment (673 bp) adjacent to the replication region of the plasmid, named pBY503, from Brevibacterium stationis IFO 12144. The function was independent of copy number control and was not associated directly with plasmid replication functions. This fragment was able to stabilize the unstable plasmids in cis but not in trans.

Base Sequence↗
PubMed1991

Effect of Y-20811, a long-lasting thromboxane A2 synthetase inhibitor, on antigen-induced airway hyperresponsiveness in guinea pigs.

Effect of Y-20811 on airway hyperresponsiveness was studied in sensitized guinea pigs. Airway hyperresponsiveness to acetylcholine (ACh) reached maximum 7 h after antigen challenge in guinea pigs sensitized actively. Y-20811 (0.3-3 mg/kg) administered orally 3 h prior to challenge inhibited this airway hyperresponsiveness in a dose-dependent manner. Y-20811 (3 mg/kg) administered orally 4 h after antigen challenge also decreased the airway hyperresponsiveness. On the other hand, Y-20811 did not affect the bronchoconstriction induced by ACh, serotonin and histamine in nonsensitized guinea pigs. The number of eosinophils in bronchoalveolar lavage fluid in the guinea pig reached the peak 7 h after antigen challenge. Y-20811 had a tendency to decrease the number of total cells, macrophages and eosinophils in a dose-dependent manner. These results suggest that Y-20811 suppress the asthmatic mechanism which causes antigen-induced airway hyperresponsiveness.

Acetylcholine↗
PubMed1991

[Effects of Y-20811, a specific thromboxane A2 synthetase inhibitor, on chemical mediator-induced bronchoconstriction in guinea pigs].

We investigated the effects of Y-20811 on chemical mediator-induced bronchoconstriction and the release of chemical mediators into lung perfusion fluid during arachidonic acid (AA)-induced bronchoconstriction in guinea pigs. Y-20811 (0.01-1 mg/kg, i.v.), like acetylsalicylic acid or indomethacin, dose-dependently suppressed arachidonic acid- and LTD4-induced bronchoconstriction, and it (1 mg/kg, i.v.) also inhibited PAF-induced bronchoconstriction in guinea pigs. However, at a dose of 1 mg/kg, i.v., it was inactive against the bronchoconstriction induced by histamine, serotonin and acetylcholine in guinea pigs. Y-20811 (0.3-10 mg/kg) administered orally also prevented the LTD4-induced bronchoconstriction in a dose-dependent manner. This protective effect of Y-20811 (10 mg/kg, p.o.) persisted for at least 24 hr. Y-20811 (10 mg/kg, p.o.) also inhibited antigen-induced bronchoconstriction in guinea pigs passively sensitized with anti-ovalbumin guinea pig serum and pretreated with mepyramine. In the perfused and ventilated guinea pig lungs, Y-20811 inhibited AA-induced bronchoconstriction, decreased the release of TXA2 (estimated as TXB2) and increased the release of PGE2 into the perfused lung fluid, significantly (TXB2 and PGE2 were measured by HPLC). Therefore, Y-20811 suppressed various stimulant-induced bronchoconstrictions through the decrease of TXA2 production and the increase of PGE2 production. Thus, Y-20811 should prove useful as an anti-asthmatic drug.

Animals↗
PubMed1990

KN-62, 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazi ne, a specific inhibitor of Ca2+/calmodulin-dependent protein kinase II.

1-[N,O-Bis(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpipera zine (KN-62), a selective inhibitor of rat brain Ca2+/calmodulin-dependent protein kinase II (Ca2+/CaM kinase II) was synthesized and its inhibitory properties in vitro and in vivo were investigated. KN-62 inhibited phosphorylation of exogenous substrate (chicken gizzard myosin 20-kDa light chain) by Ca2+/CaM kinase II with Ki value of 0.9 microM, but no significant effect up to 100 microM on activities of chicken gizzard myosin light chain kinase, rabbit brain protein kinase C, and bovine heart cAMP-dependent protein kinase type II. KN-62 also inhibited the Ca2+/calmodulin-dependent autophosphorylation of both alpha (50 kDa) and beta (60 kDa) subunits of Ca2+/CaM kinase II dose dependently in the presence or absence of exogenous substrate. Kinetic analysis indicated that this inhibitory effect of KN-62 was competitive with respect to calmodulin. However, KN-62 did not inhibit the activity of autophosphorylated Ca2+/CaM kinase II. Moreover, Ca2+/CaM kinase II bound to a KN-62-coupled Sepharose 4B column, but calmodulin did not. These results suggest that KN-62 affects the interaction between calmodulin and Ca2+/CaM kinase II following inhibition of this kinase activity by directly binding to the calmodulin binding site of the enzyme but does not affect the calmodulin-independent activity of already autophosphorylated (activated) enzyme. We examined the effect of KN-62 on cultured PC12 D pheochromocytoma cells. KN-62 suppressed the A23187 (0.5 microM)-induced autophosphorylation of the 53-kDa subunit of Ca2+/CaM kinase in PC12 D cells, which was immunoprecipitated with anti-rat forebrain Ca2+/CaM kinase II polypeptides antibodies coupled to Sepharose 4B, thereby suggesting that KN-62 could inhibit the Ca2+/CaM kinase II activity in vivo.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

Pharmacological actions of Y-24180: I. A potent and specific antagonist of platelet-activating factor.

The ability of Y-24180, 4-(2-chlorophenyl)-2-[2-(4-isobutylphenyl)ethyl]- 6,9-dimethyl-6H-thieno[3,2-f][1,2,4]triazolo[4,3-a] [1,4]diazepine to inhibit platelet-activating factor (PAF)-induced reactions was investigated. Y-24180 (0.0003-0.003 mg/kg, i.v.) dose-dependently inhibited PAF-induced bronchoconstriction in guinea pigs, but even at a high dose of 10 mg/kg, i.v., it was either inactive or weakly active against the bronchoconstriction induced by histamine, serotonin, acetylcholine, arachidonic acid, bradykinin, or leukotriene D4. Oral doses (0.003-0.1 mg/kg) of Y-24180 also prevented hemoconcentration due to PAF in a dose dependent manner and produced a parallel shift of the PAF dose-response curve. Y-24180 (0.0003-0.1 mg/kg, i.v.) and WEB 2086 (0.03-1 mg/kg, i.v.) dose-dependently reversed PAF-induced hypotension in anesthetized rats. In mice, PAF-induced lethality was inhibited by Y-24180 and WEB 2086 with ED50 values of 0.022 and 1.42 mg/kg, p.o., and 0.023 and 0.12 mg/kg, i.v., respectively. This protective effect of Y-24180 given p.o. persisted for at least 6 hr. In actively sensitized mice lethal anaphylactic shock was prevented by oral doses of Y-24180 and WEB 2086 with ED50 values of 0.095 and 0.69 mg/kg, respectively. These results suggested that Y-24180 is an extremely potent and specific PAF antagonist with a good duration of action.

Anaphylaxis↗
PubMed1990

Pharmacological actions of Y-24180, a new specific antagonist of platelet activating factor (PAF): II. Interactions with PAF and benzodiazepine receptors.

The inhibitory effect of Y-24180, 4-(2-chlorophenyl)-2-[2-(4-isobutylphenyl)ethyl]-6,9-dimethyl-6H-t hieno [3,2-f][1,2,4]triazolo [4,3-a][1,4]diazepine, on platelet activating factor (PAF)-induced platelet aggregation and the specific binding of 3H-PAF to platelets was compared with other thienodiazepine derivatives, WEB 2086 and etizolam. Y-24180 inhibited PAF-induced rabbit platelet aggregation in vitro (IC50 3.84 nM), but had little effect on adenosine diphosphate- or arachidonic acid-induced aggregation. WEB 2086 and etizolam also showed an inhibitory effect of PAF-induced aggregation (IC50 values are 456 and 6730 nM, respectively). In PAF-induced human platelet aggregation, Y-24180 (IC50 0.84 nM) was more potent than WEB 2086 (IC50 4.21 nM) and etizolam (IC50 998 nM). Y-24180, WEB 2086 and etizolam displaced 3H-PAF binding from the washed-platelets of rabbits with an IC50 value of 3.50, 9.35 and 29.5 nM, respectively. In rabbits, pretreatment with Y-24180 and WEB 2086 antagonized PAF-induced platelet aggregation dose-dependently. The significant inhibitory effect of Y-24180 (1 mg/kg, p.o.) lasted 72 hr after a single dose oral administration. WEB 2086 (10 mg/kg, p.o.) also antagonized the ex vivo response induced by PAF 1 hr after administration, but no significant effect was observed 3 hr after administration. Y-24180 displaced 3H-diazepam binding from the synaptosomal membranes of rat cerebral cortex with a Ki value of 3.68 microM. The affinity of Y-24180 for benzodiazepine(BZP) receptors was lower than those of WEB 2086 and etizolam and was about 1000 times lower than that for PAF receptors in platelets.

Animals↗
PubMed1990

Effect of cysteine ethylester hydrochloride (Cystanin) on host defense mechanisms (V): Potentiation of nitroblue tetrazolium reduction and chemiluminescence in macrophages or leukocytes of mice or rats.

L-Cysteine ethylester hydrochloride (Cystanin, ethylcysteine) at doses of 3-30 mg/kg, p.o., potentiated the reduction of nitroblue tetrazolium (NBT) by mouse peritoneal macrophages ex vivo. In in vitro experiments, this drug (30 microM) augmented NBT reduction of mouse peritoneal macrophages induced by opsonized zymosan (OZ). At the same concentration, this drug accelerated the enhancement of the OZ-induced NBT reduction by the addition of concanavalin A, N-formyl-L-methionyl-L-leucyl-L-phenylalanine or phorbol myristate acetate. This enhancing effect of ethylcysteine was completely diminished by the addition of SOD, sodium azide and catalase. In ex vivo experiments, the OZ-induced chemiluminescence of rat peritoneal macrophages and white blood cells was enhanced by the administration of ethylcysteine at doses of 3-10 mg/kg (i.p.) and 3-30 mg/kg (p.o.). In addition, this drug significantly enhanced the lumisphere-induced chemiluminescence of rat peritoneal leukocytes at 30 mg/kg (i.p.), but not the OZ-induced chemiluminescence. In in vitro experiments, this drug (30 microM) did not enhance the OZ-induced chemiluminescence response of rat peritoneal macrophages. These results suggest that ethylcysteine may enhance the intracellular generation of antimicrobial oxidants in macrophages and leukocytes.

Animals↗
PubMed1989

Phosphorylation of caldesmon.

The phosphorylation of caldesmon was studied to determine if kinase activity reflected either an endogenous kinase or caldesmon itself. Titration of kinase activity with calmodulin yielded maximum activity at substoichiometric ratios of calmodulin/caldesmon. The sites of phosphorylation on caldesmon for calcium/calmodulin-dependent protein kinase II and endogenous kinase were the same, but distinct from protein kinase C sites. Phosphorylation in the presence of Ca2+ and calmodulin resulted in a subsequent increase of endogenous kinase activity in the absence of Ca2+. These results suggest that caldesmon is not a protein kinase and that kinase activity in caldesmon preparations is due to calcium/calmodulin-dependent protein kinase II.

Animals↗
PubMed1989

Temporal pattern discrimination within the receptive field of cat retinal ganglion cells.

ON-center and OFF-center receptive fields of cat retinal ganglion cells can be divided into two categories: sensitive (type N) and insensitive (type L) to three statistical temporal visual stimuli with different second order statistics but identical first order statistics (Tsukada et al. 1982). The temporal pattern sensitivity of type N response is closely related to the nonlinear stage of Y cells depending on the interaction between center and surround mechanism. The temporal pattern sensitivity of type N responses has a spatial profile within the receptive field; it is highly sensitive in the center region of the receptive field and less sensitive toward the field periphery. The temporal pattern sensitivity in the center region of the receptive field to statistical properties (irregular or regular) of a surrounding flash annulus shows modulation like a switching element: when the surrounding area is stimulated by a more regular flash stimulus with normal distribution of inter-stimulus intervals the system is sensitive (switching on) to the temporal pattern, while a change to an irregular one with an exponential distribution makes it insensitive (switching off) to the temporal pattern.

Animals↗
PubMed1989

[Synthesis, pharmacological activity and biopharmaceutical characteristics of alpha,2-dimethyl-5H-[1]benzopyrano[2,3-b]pyridine-7-acetates].

The pro-drugs of alpha,2-dimethyl-5H-[1]benzopyrano[2,3-b]pyridine-7-acetic acid(I) with a potent anti-inflammatory activity were synthesized in order to reduce its gastrointestinal side effects. Various esters synthesized were evaluated for their anti-inflammatory activity and ulcerogenicity. Among the compounds maintaining a potent activity of I, N,N-dimethylcarbamoylmethyl alpha,2-dimethyl-5H-[1]benzopyrano[2,3-b]pyridine-7-acetate (II-18) showed excellent biopharmaceutical characteristics. The ulcerogenic effect of II-18 on the rat gastric mucosa was about 3 times less than that of I. It was suggested that II-18 may be an useful biolabile pro-drug for I among the compounds tested.

Animals↗
PubMed1989

Stimulation of phagocytic activity of leukocytes and macrophages by traxanox sodium in mice and rats.

Phagocytosis of yeast particles by mouse peritoneal macrophages or rat peritoneal polymorphonuclear leukocytes was enhanced by traxanox sodium in vitro. Traxanox sodium (30 and 100 mg/kg, p.o.) enhanced phagocytosis of yeast particles by leukocytes and macrophages in vivo or ex vivo. On the other hand, prednisolone, isoproterenol and theophylline inhibited phagocytosis by leukocytes and macrophages under the same conditions. Traxanox sodium (30 mg/kg, p.o.) prevented the suppression of phagocytosis by the above drugs. Combined with theophylline, isoproterenol synergistically inhibited phagocytosis by leukocytes in vivo. Traxanox sodium (100 mg/kg, p.o.) administered alone had no influence on carbon clearance in normal mice. However, traxanox sodium (1-30 mg/kg, p.o.) prevented the suppression of carbon clearance by the treatment with carrageenan, but not by the treatment with ethyl palmitate. These results suggest that traxanox sodium stimulates the phagocytic activity of leukocytes or macrophages and prevents the drug-induced suppression of the phagocytic activity of these cells.

Animals↗
PubMed1988

Increased serum immunoreactive prolyl hydroxylase in rats with carrageenan-induced granuloma and adjuvant arthritis.

The authors developed a competitive enzyme immunoassay for serum immunoreactive prolyl hydroxylase (SIRPH) as a marker of fibrogenesis, and examined the changes in SIRPH concentrations in rats with carrageenan-induced granuloma and adjuvant arthritis. The effects of such anti-inflammatory agents as prednisolone, pranoprofen, indomethacin, and hydrocortisone were also investigated. Prolyl hydroxylase activity in rats with carrageenan-induced granuloma and adjuvant arthritis increased inflammatory granulation tissue, and the concentrations of SIRPH also increased time dependently. The nontreated controls showed a constant low level of SIRPH. After treatment with anti-inflammatory agents or removal of the granuloma, SIRPH levels decreased coincident with the improvement of clinical symptoms. It was assumed that immunoreactive prolyl hydroxylase was released into the blood stream as a result of increased turnover of the enzyme protein owing to fibrotic disorders. SIRPH could be a useful biochemical marker for assessing therapeutic effects through the actual activity of fibrogenesis.

Animals↗
PubMed1988

[Effects of traxanox sodium on experimental nasal allergy].

The anti-allergic actions of traxanox sodium pentahydrate (traxanox) were examined using experimental allergic rhinitis models. Traxanox (10 and 30 mg/kg, p.o.), tranilast (30 and 100 mg/kg, p.o.) and disodium cromoglycate (DSCG, 3 and 10 mg/kg, i.v.) dose-dependently inhibited the increase of dye leakage in rats actively sensitized with dinitrophenol-coupled ascaris extract. Traxanox was about 4 times more potent than tranilast. In this test, the inhibitory activity of traxanox (30 mg/kg, p.o.) was not affected by predosing with the same dose for 7 days. In addition, traxanox (1-10 mg/kg, i.v.) inhibited the allergically induced increase in nasal resistance of guinea pigs actively sensitized with egg albumin, while tranilast (10 mg/kg, i.v.), DSCG (100 mg/kg, i.v.) and mepyramine (1 mg/kg, i.v.) had little effect. These results suggest that traxanox may be clinically effective in treating patients with nasal allergies.

Airway Resistance↗
PubMed1988

[Anti-rheumatic action of cysteine ethylester hydrochloride].

Ethylcysteine showed a prophylactic effect on collagen-induced arthritis in rats at 100 mg/kg, p.o., and the effect continued even after stopping the administration. However, it was not dose-dependent. D-penicillamine showed no effect under the same condition. Ethylcysteine tended to inhibit collagen-induced arthritis when it was administered therapeutically at 300 mg/kg, p.o. Moreover, it had little effect on the acute inflammatory and type I allergy models such as carrageenin induced edema, 48 hr homologous PCA, and 6 hr and 24 hr Evans blue-carrageenin pleurisy in rats. In the in vitro assay, ethylcysteine had the following effects: inactivation of the rheumatoid factor, the acceleration of the denaturation of human gamma-globulin and the inhibition of bone alkaline phosphatase. The effect were as potent as those of D-penicillamine. As to the results, the mode of action of ethylcysteine is the same as that of D-penicillamine in terms of the biochemical properties. However, ethylcysteine showed an inhibitory effect on collagen-induced arthritis which was not demonstrated with D-penicillamine, so this drug may have a clinically anti-rheumatic action.

Administration, Oral↗