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Biomedical subjects

A Inoue

Publications and source records attributed to A Inoue.

At least 73 records · Page 4Linked to original sources
PubMed1990

Serotypes and antimicrobial susceptibility of Pseudomonas aeruginosa strains isolated from diseased dogs.

Strains of Pseudomonas aeruginosa isolated from diseased dogs in Tokyo area during 1983 through 1986 were serotyped and assayed for antimicrobial susceptibility to obtain an epizootiological aspect of canine P. aeruginosa infection. Major sources of specimens were ear and nasal discharges and urine. The results of O-antigen typing using a monoclonal antibody kit showed that the most predominant serotype was type M. Types G and B were also major serotypes. In a yearly distribution of serotypes, type I was almost limited in 1986, and was isolated mainly from surgical wounds, which showed an episode of nosocomial infection, whereas that of type M or B was dispersed during 4 years from 1983 to 1986. As a result of antimicrobial susceptibility test, most canine strains were considered to be susceptible to 4 drugs, which were commonly used in both human and veterinary clinics, in contrast to human isolates.

Animals↗
PubMed1990

Characterization of cells cultured from human giant-cell tumors of bone. Phenotypic relationship to the monocyte-macrophage and osteoclast.

Cell culture techniques were used to clarify the histogenesis of giant-cell tumor of bone. Even after passage, nearly all of the mononuclear cells possessed tartrate-resistant acid phosphatase and receptors for eel calcitonin, which are both phenotypic markers for osteoclasts. Eel calcitonin produced an increase in the cyclic adenosine monophosphate (cAMP) content of the mononuclear cells. More than 90% of mononuclear tumor cells expressed monocyte markers; flow cytometric C3b receptor, a macrophage marker, was also detected in a few cells. These findings demonstrate that the mononuclear cells expressed phenotypes of both the osteoclast and monocyte-macrophage and that they originate in a monocyte-macrophage-osteoclast lineage. Giant-cell tumor of bone may thus provide a good model for investigating the mechanism of bone resorption in which cells of osteoclast lineage play a central role.

Biomarkers↗
PubMed1990

[A case of malignant fibrous histiocytoma of the cecum].

A case of primary malignant fibrous histiocytoma (MFH) of the cecum was reported. Patient was a 52-year-old female, and complained of right lower abdominal pain. The barium enema and abdominal computed tomography demonstrated a localized mass involving the entire circumference of the cecum. Right hemicolectomy was performed and the resected specimen revealed a tumor of 8 X 6 X 5 cm in size extending to the entire circumference of the cecum. The histopathological examination revealed a storiform pattern, which was diagnostic of MHF. The tumor proliferated chiefly in the subserous tissue and partially infiltrated the tunica muscularis propria. The postoperative course was uneventful and she showed no sign of recurrence at 15 months after operation. This is the ninth reported case of primary MFH in digestive organs.

Cecal Neoplasms↗
PubMed1990

Reverse triiodothyronine nuclear binding in rat brain.

Reverse triiodothyronine (rT3) had been believed biologically inactive, but recently we demonstrated nuclear binding sites for rT3 in human placenta. In this study we examined rT3 binding sites in rat brain. Male Wistar normal rats aged 2, 4 and 9 weeks were killed and the brain was removed for rT3 binding assay. In another series, male Wistar rats weighing about 40g were divided into two groups: group 1 (rickets group), kept on our original rachitogenic diet and group 2, kept on standard diet. After 28 days on either diet they were killed and the brain was removed for assay. Cerebral nuclear protein was extracted with 0.4M KCl buffer. In normal 2 week-old rats specific binding sites for rT3 were detected in all parts of the brain, but at 7 weeks of age the density of the binding sites was decreased and at 9 weeks it is almost 0. Scatchard analysis performed in rachitic rats showed a curvilinear pattern, suggesting two sets of receptors existing in brain tissue; in cerebral cortex one with a association constant (Ka) of 1.07 X 10(8)M-1 and a limited capacity (Bmax) of 0.75 X 10(-15) moles/mg tissue and the other with Ka = 4.93 X 10(6), Bmax = 12.1 X 10(-15), and in thalamus including hypothalamus, one with Ka = 1.00 X 10(8), Bmax = 1.00 X 10(-15) and the other with Ka = 4.57 X 10(6) and Bmax = 18.6 X 10(-15).

Animals↗
PubMed1989

Two distinct nonmuscle myosin-heavy-chain mRNAs are differentially expressed in various chicken tissues. Identification of a novel gene family of vertebrate non-sarcomeric myosin heavy chains.

Two distinct cDNA clones for nonmuscle myosin heavy chain (MHC) were isolated from a chicken fibroblast cDNA library by cross-hydridization under a moderate stringency with chicken gizzard smooth muscle MHC cDNA. These two fibroblast MHC and the gizzard MHC are each encoded in different genes in the chicken genome. Northern blot analysis showed that both of the nonmuscle MHC mRNAs were expressed not only in fibroblasts but also in a variety of tissues including brain, lung, kidney, spleen, and skeletal, cardiac and smooth muscles. However, the relative contents of the two nonmuscle MHC mRNAs varied greatly among tissues. The encoded amino acid sequences of the nonmuscle MHCs were highly similar to each other (81% identity) and to the smooth muscle MHC (81-84%), but much less similar to vertebrate skeletal muscle MHCs (38-41%) or to protista nonmuscle MHCs (35-36%). A phylogenic tree of MHC isoforms was constructed by calculating the similarity scores between these MHC sequences. An examination of the tree showed that the vertebrate sarcomeric (skeletal and cardiac) MHC isoforms are encoded in a very closely related multigene family, and that the vertebrate non-sarcomeric (smooth muscle and nonmuscle) MHC isoforms define a distinct, less conserved MHC gene family.

Amino Acid Sequence↗
PubMed1989

The human preproendothelin-1 gene. Complete nucleotide sequence and regulation of expression.

Endothelin-1 is a 21-amino acid potent vasoconstrictor peptide produced by vascular endothelial cells. We have cloned the whole length of the human preproendothelin-1 (PPET-1) gene and the corresponding cDNA and determined the complete nucleotide sequences. The 2026-nucleotide human mRNA for PPET-1 (excluding the polY(A) tail) is encoded in five exons distributed over 6836 base pairs of the genome. The 5'-flanking region of the gene contains (i) octanucleotide sequences for the phorbol ester-responsive elements, also known as the binding elements for FOS.JUN complex; (ii) consensus motifs for the binding site of nuclear factor 1, which may mediate the induction described previously of PPET-1 mRNA by transforming growth factor-beta; (iii) hexanucleotide sequences for the acute phase reactant regulatory elements that may be involved in the induction of endothelin-1 under acute physical stress in vivo. Further, the 3'-nontranslated sequence of human PPET-1 mRNA contains three AUUUA motifs, which may mediate selective translation-dependent destabilization of the mRNA. Northern blot analysis in cultured endothelial cells from human umbilical veins shows that PPET-1 mRNA is in fact rapidly induced by the active phorbol ester 12-O-tetradecanoylphorbol 13-acetate within 10 min. Analysis of mRNA life span by using actinomycin D demonstrates that PPET-1 mRNA has a short intracellular half-life of about 15 min and is superinduced by cycloheximide. This superinduction is found to be due to the stabilization of the mRNA by cycloheximide, as in the case of other known AUUUA-containing mRNAs. These findings suggest that the regulation of expression of PPET-1 mRNA may be mediated in part by these sequence elements.

Amino Acid Sequence↗
PubMed1989

Unesterified long-chain fatty acids inhibit thyroid hormone binding to the nuclear receptor. Solubilized receptor and the receptor in cultured cells.

Unesterified long-chain fatty acids strongly inhibited thyroid hormone (T3) binding to nuclear receptors extracted from rat liver, kidney, spleen, brain, testis and heart. Oleic acid was the most potent inhibitor, attaining 50% inhibition at 2.8 microM. Oleic acid similarly inhibited the partially purified receptor and enhanced dissociation of the preformed T3-receptor complex. The fatty acid acted in a soluble form and in a competitive manner for the T3-binding sites, thereby reducing the affinity of the receptor for T3. The affinity of the receptor for oleic acid (Ki) was 1.0 microM. In HTC rat hepatoma cells in culture, fatty acids added to the medium reached the nucleus and inhibited nuclear T3 binding; oleic acid being the most potent. T3 binding of the cells was reversibly restored in fresh medium free of added fatty acids. Oleic acid did not affect all the T3-binding sites in the HTC cells: one form (80%) was inhibited and the other was not and these two forms were commonly present in all rat tissues examined. Thus, fatty acids inhibited the solubilized nuclear receptor as well as a class of nuclear T3-binding sites in cells in culture.

Animals↗
PubMed1989

Two isoforms of smooth muscle myosin regulatory light chain in chicken gizzard.

We isolated a cDNA clone for a new isoform of chicken smooth muscle myosin regulatory light chain (MRLC) from a cDNA library of embryonic chicken gizzard. The deduced amino acid sequence was different in 10 amino acid residues from the previously reported polypeptide sequences of chicken gizzard MRLC. The in vitro transcription/translation product from the cDNA comigrated with a minor isoform of chicken gizzard MRLC (L20-B) in a two-dimensional gel electrophoresis. This isoform was detected only in the embryonic gizzard and was slightly more acidic than the predominant isoform (L20-A). The partial polypeptide sequence of L20-A was confirmed to be identical to the previously reported MRLC sequence. Nevertheless, Northern blot analysis showed that L20-B-related mRNAs were present in both the embryonic and adult gizzard. Non-denaturing pyrophosphate polyacrylamide gel electrophoresis showed that the in vitro transcription/translation product could be associated with native myosin when mixed and coprecipitated in a low-ionic-strength buffer with adult chicken gizzard myosin. Moreover, the coprecipitated translation product was phosphorylated in vitro by chicken gizzard myosin light chain kinase apparently more rapidly than L20-A on the native myosin heavy chain. From these findings, we concluded that at least two isoforms of smooth muscle MRLC exist in chicken gizzard and that their expression may be regulated translationally depending on the developmental stage.

Amino Acid Sequence↗
PubMed1989

DNA binding property of vitamin D3 receptors associated with 26,26,26,27,27,27-hexafluoro-1,25-dihydroxyvitamin D3.

Using [3H]-26,26,26,27,27,27-hexafluoro-1,25-dihydroxyvitamin D3 (F6-1,25-(OH)2D3), we have examined its ability to bind to the 1,25-(OH)2D3 receptor, and the ability of the resulting complex to bind DNA. The binding sites for [3H]F6-1,25-(OH)2D3 in the chick intestinal receptor represented a limited number of saturable sites for which 1,25-(OH)2D3 competes. 1,25-Dihydroxyvitamin D3 is three times more active than F6-1,25-(OH)2D3 in displacing [3H]F6-1,25-(OH)2D3. By affinity chromatography using DNA-Sephadex, the [3H]F6-1,25-(OH)2D3 receptor complex eluted from the column in a single peak at 0.14 M KCl, while [3H]-1,25-(OH)2D3 receptor complex eluted at 0.13 M KCl. These results indicate that F6-1,25-(OH)2D3 and 1,25-(OH)2D3 recognize the same binding site of the receptor and that the F6-1,25-(OH)2D3 receptor complex binds DNA more tightly than the 1,25-(OH)2D3 receptor complex. We suggest that the higher binding affinity for DNA may contribute to the greater biological activity of F6-1,25-(OH)2D3.

Animals↗
PubMed1989

The human endothelin family: three structurally and pharmacologically distinct isopeptides predicted by three separate genes.

Three distinct human endothelin-related genes were cloned by screening a genomic DNA library under a low hybridization stringency with a synthetic oligonucleotide probe encoding a portion of the endothelin sequence. Genomic Southern blot analysis with the same oligonucleotide probe showed three corresponding chromosomal loci not only in the human genome but also in porcine and rat genomes. The nucleotide sequences of the three human genes were highly conserved within the regions encoding the 21-residue (mature) endothelins, in spite of the fact that the immediately upstream exon sequences, which encode a part of the propeptides, retained little similarity. Moreover, each of the human genes predicted a putative 21-residue peptide, similar to but distinct from each other: (i) the "classical" endothelin (ET-1), (ii) [Trp6,Leu7]endothelin (ET-2), and (iii) [Thr2,Phe4,Thr5,Tyr6, Lys7,Tyr14]endothelin (ET-3). Synthetic ET-1, ET-2, and ET-3 were prepared according to the deduced amino acid sequences, and the biological activities were assayed by contraction of isolated porcine coronary artery strips and by intravenous injection to anesthetized rats. All these synthetic peptides produced strong vasoconstrictor and pressor responses. However, the quantitative profiles of the pharmacological activities were considerably different among the three isopeptides, suggesting the possible existence of endothelin receptor subtypes.

Animals↗
PubMed1989

Interaction of two heads of myosin with F-actin: binding of H-meromyosin with F-actin in the absence of nucleotide.

The bindings of S-1 and the two heads of HMM with pyrene-labeled F-actin were studied using the change in light-scattering intensity or that in the fluorescence intensity of the pyrenyl group. At low ionic strength (50 mM KCl), both S-1 and HMM became bound tightly with F-actin (Kd less than 0.1 microM) and both heads of HMM became bound to F-actin. The affinities of S-1 and HMM for F-actin decreased with increasing KCl concentration. In 1 M KCl, the Kd values of S-1 and HMM for F-actin were 11 and 0.58 microM, respectively. Thus, HMM was bound to F-actin 19 times more tightly than S-1. We compared the extent of binding of HMM to F-actin measured by a centrifugation method with that measured by the fluorescence change of pyrenyl-group, and found that even in 1 M KCl, HMM became bound to F-actin with a two-headed attachment. We measured the kinetics of binding and dissociation of acto-S-1 and acto-HMM from the time course of the change in light-scattering intensity after mixing S-1 or HMM with F-actin at 1 M KCl and that after mixing 1 M KCl with acto-S-1 or acto-HMM formed at low ionic strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1989

Reaction intermediates formed by myofibrils during the ATPase reaction under relaxed conditions.

The species and amounts of intermediates formed by myosin in myofibrils during the ATPase reaction under relaxed conditions were examined. The amount of total nucleotides (ADP + ATP) bound to myofibrils, determined by a centrifugation method or a rapid filtration method, was 0.86 mol/mol myosin head. The amount of bound ADP, determined as the ADP remaining in the mixture after free ADP had been rapidly converted into ATP by an ATP-regenerating system, was found to be 0.67 mol/mol myosin head. We examined the time courses of free-Pi and total-Pi (TCA-Pi) formation after adding ATP to the myofibrils. The amount of Pi bound to myofibrils, calculated by subtracting the burst size of free Pi (0.23 mol/mol myosin head) from that of TCA-Pi (0.60 mol/mol myosin head), was found to be 0.37 mol/mol myosin head. The amount of tightly bound ATP determined by an ATP-quenching method was very low (0.03 mol/mol myosin head). If there is no myosin-phosphate complex, then the amounts of the myosin-phosphate-ADP complex, MADPP, and the tightly bound myosin-ATP complex, M*ATP, are 0.37 and 0.03 mol/mol myosin head, respectively, whereas the amounts of myosin-ADP and loosely bound myosin-ATP complexes are 0.30 and 0.16 mol/mol myosin head, respectively. Thus, half of the myosin heads forms MADPP or M*ATP, and the equilibrium between MADPP and M*ATP shifts to the MADPP side. These results agree with those obtained for myosin in solution (Inoue, A., Takenaka, H., Arata, T., & Tonomura, Y. (1979) Adv. Biophys. 13, 1-194). Therefore, in relaxed myofibrils the active site of myosin does not interact with actin.

Adenosine Diphosphate↗
PubMed1989

Oxygen exchange reaction during ATP hydrolysis by glycerinated muscle fibers, myofibrils, and synthetic actomyosin filaments.

The oxygen exchange during ATP hydrolysis by glycerinated muscle fibers, myofibrils, and synthetic actomyosin filaments was studied from the distribution of the [18O]Pi species produced by the hydrolysis of [gamma-18O]ATP. The products were mixtures of two species, one with a low extent of oxygen exchange and the other with a high extent. The low and high extents of oxygen exchange in these two Pi species were the same as those of the acto-S-1 ATPase reaction through the routes with and without the dissociation of actomyosin, respectively (Yasui, M., Ohe, M., Kajita, A., Arata, T., & Inoue, A. [1988] J. Biochem. 104, 550-559). During isometric contraction of glycerinated muscle fibers at 20 degrees C, the fraction of ATP hydrolysis with low extent of oxygen exchange was 0.83 and 0.70, respectively, in 0 and 120 mM KCl. In myofibrils, the fraction of ATP hydrolysis with a low extent of oxygen exchange was 0.72-0.88 in 0-120 mM KCl at 20 degrees C. Therefore, in glycerinated muscle fibers and myofibrils ATP seems to be mainly hydrolyzed through a route without the dissociation of actomyosin, especially at low ionic strength and at room temperature when the tension development is high. ATP hydrolysis through this route may be coupled with muscle contraction.

Adenosine Diphosphate↗
PubMed1989

Sympathetic inhibition and vasopressin mediation during centrally induced responses to serotonin in rats.

To study mechanisms underlying the cardiovascular effects of centrally administered serotonin, we recorded responses to intracerebroventricular (i.c.v.) injections of serotonin in urethane-anesthetized rats. Dose-related increases in blood pressure accompanied by reductions in heart rate and sympathetic nerve firing were elicited consistently. The diminution in sympathetic nerve activity implies that while sympathetic inhibition could contribute to the bradycardia, sympathetic activation alone cannot account for the pressor response. Pressor and bradycardic responses must have been caused by activation of specific serotonergic receptors in the brain because both responses were inhibited following serotonin blockade produced by i.c.v. injection of methysergide. By contrast, intravenous injection of a vasopressin antagonist inhibited the pressor response selectively, thereby suggesting that peripheral mediation of the pressor (but not the bradycardic) response involves release of endogenous vasopressin. Collectively, our results are compatible with the interpretation that i.c.v.-injected serotonin acts on serotonergic brain receptors to elevate blood pressure by releasing endogenous vasopressin, and slow the heart through sympathetic inhibition.

Animals↗