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Watanabe H, Masaki H, Asoh N, Watanabe K, Oishi K, Kobayashi S, Sato A, Nagatake T. Molecular analysis of methicillin-resistant Staphylococcus aureus as a causative agent of bronchopulmonary infection: relation to colonization in the upper respiratory tract. J Clin Microbiol 2000; 38:3867-9. [PMID: 11015423 PMCID: PMC87496 DOI: 10.1128/jcm.38.10.3867-3869.2000] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2000] [Accepted: 08/01/2000] [Indexed: 11/20/2022] Open
Abstract
Using five diagnostic markers, we compared the types of 72 strains of methicillin-resistant Staphylococcus aureus (MRSA) isolated simultaneously from the nasal cavity, pharynx, and sputum from 24 patients. Almost identical MRSA types had colonized the nasal cavity and sputum from the same patient for 21 (88%) of the patients. We speculate that most MRSA organisms isolated in sputum are derived from the nasal cavity, while a few are derived from the pharynx.
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Matsubara H, Moriguchi Y, Mori Y, Masaki H, Tsutsumi Y, Shibasaki Y, Uchiyama-Tanaka Y, Fujiyama S, Koyama Y, Nose-Fujiyama A, Iba S, Tateishi E, Iwasaka T. Transactivation of EGF receptor induced by angiotensin II regulates fibronectin and TGF-beta gene expression via transcriptional and post-transcriptional mechanisms. Mol Cell Biochem 2000; 212:187-201. [PMID: 11108151 DOI: 10.1023/a:1007189828584] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The signaling cascade elicited by angiotensin II (Ang II) resembles that characteristic of growth factor, and recent evidence indicates transactivation of epidermal growth factor receptor (EGF-R) by G protein-coupled receptors. Here, we report the involvement of EGF-R in Ang II-induced synthesis of fibronectin and TGF-beta in cardiac fibroblasts. Ang II stimulated fibronectin mRNA levels dose-dependently with a maximal increase (approximately 5-fold) observed after 12 h of incubation. Ang II-, or calcium ionophore-induced fibronectin synthesis was completely abolished by tyrosine kinase inhibitors and intracellular Ca2+ chelating agents. Ang II-induced fibronectin mRNA was not affected by PKC inhibitors or PKC depletion, whereas specific inhibition of EGF-R function by a dominant negative EGF-R mutant and tyrphostin AG1478 abolished induction of fibronectin mRNA. We isolated the rat fibronectin gene including the 5'-flanking region and found that the AP-1 binding site present in the promoter region was responsible for the Ang II responsiveness of this gene. Gel retardation assay revealed the binding of nuclear protein to the AP-1 site, which was supershifted with anti-c-fos and anti-c-jun but not anti-ATF-2 antibodies. Conditioned medium from Ang II-treated cells contained TGF-beta bioactivity and addition of neutralizing TGF-beta antibody modestly (46%) inhibited induction of fibronectin. Ang II-induced synthesis of TGF-beta was also abolished by inhibition of EGF-R function. The effect of TGF-beta was exerted by stabilizing fibronectin mRNA without affecting the promoter activity and required de novo protein synthesis. We concluded that Ang II-induced expression of fibronectin and TGF-beta is mediated by downstream signaling of EGF-R transactivated by Ca2+-dependent tyrosine kinase, and that Ang II-induced fibronectin mRNA expression is regulated by two different mechanisms; transcriptional control by binding of c-fos/c-jun complex to the AP-1 site, and post-transcriptional control by mRNA stabilization due to autocrine and/or paracrine effects of TGF-beta. Thus, this study suggested that the action of Ang II on extracellular matrix formation should be interpreted in association with the EGF-R signaling cascade.
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Komiyama Y, Nishimura N, Dong XH, Hirose S, Kosaka C, Masaki H, Masuda M, Takahashi H. Liquid chromatography mass spectrometric analysis of ouabainlike factor in biological fluid. Hypertens Res 2000; 23 Suppl:S21-7. [PMID: 11016815 DOI: 10.1291/hypres.23.supplement_s21] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Ouabainlike factor (OLF), assayed as ouabainlike immunoreactivity (OLI), is a probable endogenous digitalislike factor (EDLF). Liquid chromatography/mass spectrometry (LC/MS) is one of the most highly sensitive tools for obtaining structural information regarding low-molecular weight materials in a target compound, and to measure the concentrations of these materials. We have previously reported that OLI can be isolated from the culture supernatant of the rat pheochromocytoma cell line, PC12, by several reverse-phase chromatography and LC/MS techniques. The present study was performed to characterize OLF from biological fluids such as plasma and culture supernatant of PC12 cells by LC/MS. The previous applications of LC/MS to OLI in plasma have been limited to structural identification at the final stages of isolation, in which the starting volume of plasma has been over 10 I. In the present study, we tried to minimize the volume of plasma, and to develop a new preclearing step to gain adequate LC/MS characterization using MS/MS analysis. The plasma was acidified, and OLI was purified by ODS column chromatography. OLI in chromatographic fractions from plasma was assayed by a sensitive enzyme-linked immunosorbent assay for ouabain. After Sep-Pak treatment and two rounds of ODS column chromatography, OLI was identified from 80 ml of plasma. The structure of the purified OLI was identical to authentic ouabain and digoxin, as assessed by LC/MS. In conclusion, we identified the chemically or structurally clarified ouabain and digoxin as the circulating form in plasma by LC/MS.
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Murasawa S, Matsubara H, Mori Y, Masaki H, Tsutsumi Y, Shibasaki Y, Kitabayashi I, Tanaka Y, Fujiyama S, Koyama Y, Fujiyama A, Iba S, Iwasaka T. Angiotensin II initiates tyrosine kinase Pyk2-dependent signalings leading to activation of Rac1-mediated c-Jun NH2-terminal kinase. J Biol Chem 2000; 275:26856-63. [PMID: 10856308 DOI: 10.1074/jbc.m909999199] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ca(2+)-sensitive tyrosine kinase Pyk2 was shown to be involved in angiotensin (Ang) II-mediated activation of extracellular signal-regulated kinase (ERK) via transactivation of epidermal growth factor receptor (EGF-R). In this study, we tested the involvement of Pyk2 and EGF-R in Ang II-induced activation of JNK and c-Jun in cardiac fibroblasts. Ang II markedly stimulated JNK activities, which were abolished by genistein and intracellular Ca(2+) chelators but partially by protein kinase C depletion. Inhibition of EGF-R did not affect Pyk2 and JNK activation by Ang II. Stable transfection with a dominant negative (DN) mutant for Pyk2 (PKM) completely blocked JNK activation by Ang II. DN mutants of Rac1 (DN-Rac1) and MEK kinase (DN-MEKK1) also abolished it, whereas those of Cdc42, RhoA, and Ha-Ras had no effect. Induction of c-Jun gene transcription by Ang II was abolished in PKM, DN-Rac1, and DN-MEKK1, in which Ang II-induced binding of ATF2/c-Jun heterodimer to the activator protein-1 sequence at -190 played a key role. These results suggest that 1) in cardiac fibroblasts activation of JNK and c-Jun by Ang II is initiated by Pyk2-dependent signalings but not by downstream signals of EGF-R or Ras, 2) Rac1 but not Cdc42 is required for JNK activation by Ang II upstream of MEKK1, and 3) ATF-2/c-Jun binding to the activator protein-1 sequence at -190 plays a key role for induction of c-Jun gene by Ang II.
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Matsumoto K, Urano M, Hirai M, Masaki H, Tenjin H, Mineura K. Haemodynamic evaluation of cerebral arteriovenous malformations by quantification of transit time using high speed digital subtraction angiography: basic considerations. J Clin Neurosci 2000; 7 Suppl 1:39-41. [PMID: 11013096 DOI: 10.1054/jocn.2000.0709] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
It is important to evaluate the haemodynamics of cerebral arteriovenous malformations (AVMs) in order to predict and avoid complications following surgical intervention. This study measured the transit time of each component of AVMs by high-speed digital subtraction angiography (DSA) to understand the haemodynamics and to evaluate which parameter is an appropriate indicator for the monitoring. Eleven cases of cerebral AVMs were studied. Haemodynamics were evaluated by analysis of tracer transit using DSA. Tracer transit parameters including transit time and peak time were calculated by application of gamma fitting to time density curve, and measured in the following compartments; feeding artery, nidus and draining vein. Significant correlations of tracer transit parameters were present among compartments. Although there was no significant correlation of nidus volume and tracer transit parameters, the peak time was shorter in haemorrhage cases than in non-haemorrhage cases. Measurements of tracer transit parameters by high-speed DSA may be a useful tool for characterising and monitoring the haemodynamics of AVMs following surgical intervention.
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Tomita K, Ogawa T, Uozumi T, Watanabe K, Masaki H. A cytotoxic ribonuclease which specifically cleaves four isoaccepting arginine tRNAs at their anticodon loops. Proc Natl Acad Sci U S A 2000; 97:8278-83. [PMID: 10880568 PMCID: PMC26938 DOI: 10.1073/pnas.140213797] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Colicin D has long been thought to stop protein synthesis in infected Escherichia coli cells by inactivating ribosomes, just like colicin E3. Here, we show that colicin D specifically cleaves tRNAs(Arg) including four isoaccepting molecules both in vivo and in vitro. The cleavage occurs in vitro between positions 38 and 39 in an anticodon loop with a 2',3'-cyclic phosphate end, and is inhibited by a specific immunity protein. Consistent with the cleavage of tRNAs(Arg), the RNA fraction of colicin-treated cells significantly reduced the amino acid-accepting activity only for arginine. Furthermore, we generated a single mutation of histidine in the C-terminal possible catalytic domain, which caused the loss of the killing activity in vivo together with the tRNA(Arg)-cleaving activity both in vivo and in vitro. These findings show that colicin D directly cleaves cytoplasmic tRNAs(Arg), which leads to impairment of protein synthesis and cell death. Recently, we found that colicin E5 stops protein synthesis by cleaving the anticodons of specific tRNAs for Tyr, His, Asn, and Asp. Despite these apparently similar actions on tRNAs and cells, colicins D and E5 not only exhibit no sequence homology but also have different molecular mechanisms as to both substrate recognition and catalytic reaction.
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Mori Y, Kishimoto N, Imai Y, Tanaka Y, Fujiyama A, Shibasaki Y, Nagata T, Masaki H, Umeda Y, Matsubara H, Iwasaka T. Cryofiltration and oral corticosteroids provide successful treatment for an elderly patient with cryoglobulinemic glomerulonephritis associated with hepatitis C virus infection. Intern Med 2000; 39:564-9. [PMID: 10888213 DOI: 10.2169/internalmedicine.39.564] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A 75-year-old man was admitted due to nephrotic syndrome, purpura on the legs, which was associated with hepatitis C virus (HCV), and type II mixed cryoglobulinemia. Renal biopsy revealed features of cryoglobulinemic glomerulonephritis. Since the patient was elderly and the HCV genotype was Ib, interferon-alpha for reducing HCV was not indicated. Four sessions of cryofiltration and the administration of corticosteroids improved the proteinuria and renal function strikingly without adverse effects. This case demonstrates that an elderly patient who has nephrotic syndrome caused by cryoglobulinemic glomerulonephritis associated with HCV can be treated safely by cryofiltration with low doses of oral corticosteroids.
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58
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Masaki H, Takasawa N, Yamazaki K. An electrophysiological study of the locus of the interference effect in a stimulus-response compatibility paradigm. Psychophysiology 2000; 37:464-72. [PMID: 10934905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
This study investigated the locus of the interference effect in a stimulus-response compatibility task using event-related potentials (ERPs). Ten participants were instructed to respond to stimulus color with the left or right middle finger. Red or blue arrows pointed in the same direction as the response hand on congruent trials and pointed in the opposite direction on incongruent trials. Neutral trials were red or blue horizontal bars. Reaction times (RTs) to incongruent stimuli were significantly longer than RTs to congruent stimuli. The peak latency of the P300 for incongruent stimuli was significantly longer than that for congruent stimuli. In addition, onset of stimulus-locked lateralized readiness potential (LRPs) was significantly later for incongruent stimuli than for congruent stimuli. However, electromyogram (EMG)-locked LRPs for incongruent stimuli showed incorrect preparation. These results suggest that the interference effect might occur at the stage in which stimulus evaluation processes and response-related processes overlap.
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Masaki H, Tamura M, Kurane I. Induction of cytotoxic T lymphocytes of heterogeneous specificities by immunization with a single peptide derived from influenza A virus. Viral Immunol 2000; 13:73-81. [PMID: 10733170 DOI: 10.1089/vim.2000.13.73] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
We examined whether immunization with a single peptide induces cytotoxic T lymphocytes (CTLs) of heterogeneous specificities in vivo. Immunization of BALB/c mice with the peptide H2:529-537, which corresponded to amino acid residues 529-537 on the HA2 subunit transmembrane region of influenza A/Jap virus (H2N2) and possessed an H-2Kd-binding motif, induced CD8+CD4- CTLs. These CTLs lysed influenza A/Jap virus-infected target cells as well as those pulsed with the H2:529-537 peptide. H2:529-537 peptide-induced CTLs also lysed to lower but significant levels the target cells pulsed with the H1:533-541 peptide, which corresponded to amino acid residues 533-541 on the HA2 subunit transmembrane region of influenza A/PR/8 virus (H1N1) and were compatible to H2:529-537. Immunization with the H1:533-541 peptide, which also possessed an H-2Kd-binding motif, induced CTLs in vivo. H1:533-541-induced CTLs lysed influenza A/PR/8 virus-infected target cells and those pulsed with the peptide H1:533-541. Subtype cross-reactive CTLs to the H2:529-537 peptide were not induced by immunization with the H1:533-541 peptide. Two peptides, H2:3S and H2:7S, which had one amino acid substitution, serine at the third and seventh positions, respectively, induced CTLs that lysed target cells pulsed with the respective peptides to the highest levels. These results indicate that immunization with a single peptide induces CTLs of heterogeneous specificities in vivo.
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Takada K, Masaki H, Konishi E, Takahashi M, Kurane I. Definition of an epitope on Japanese encephalitis virus (JEV) envelope protein recognized by JEV-specific murine CD8+ cytotoxic T lymphocytes. Arch Virol 2000; 145:523-34. [PMID: 10795519 DOI: 10.1007/s007050050043] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We defined an epitope on the Japanese encephalitis virus (JEV) envelope (E) protein recognized by CD8+ cytotoxic T lymphocytes (CTLs). CTLs induced in JEV-infected BALB/c (H-2d) mice recognized E and/or premembrane (PrM) proteins, while CTLs in C57BL/6J (H-2b) and C3H/HeJ (H-2k) mice did not. JEV-specific CTLs had a phenotype of CD3+ CD4- CD8+. Twenty-four 9-amino acid (a.a.) peptides, which had binding motifs for H-2Kd, H-2Ld or H-2Dd, were synthesized according to the amino acid sequences of PrM and E proteins. CTLs induced by JEV infection recognized only the peptide K-3. Immunization of BALB/c mice with only a group of peptides including K-3 induced CTLs which recognized the homologous K-3 peptide, while immunization with other peptides did not. The peptide K-3 had a binding motif for H-2Kd. This is consistent with the finding that JEV-specific CTLs in BALB/c mice was H-2Kd-restricted. These results indicate that the epitope recognized by CTLs in BALB/c mice is located between a.a. 60 and 68 on the E protein, corresponding to an a.a. sequence of CYHASVTDI.
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Motomura K, Takasugi M, Furumoto A, Akahori H, Masaki H, Watanabe H, Oishi K, Nagatake T. [Clinical features and etiology of community-acquired pneumonia at a general hospital between 1994 and 1997]. NIHON KOKYUKI GAKKAI ZASSHI = THE JOURNAL OF THE JAPANESE RESPIRATORY SOCIETY 2000; 38:267-72. [PMID: 10879028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
To characterize the clinical features and etiology of recently encountered cases of community-acquired pneumonia (CAP), we carried out a hospital-based retrospective study of 120 episodes of CAP (115 patients) at Tagami Hospital, Nagasaki City between 1994 and 1997. We identified the causative pathogens in 55 episodes (50 patients) by sputum Gram stain and quantitative culture, for a determination rate of 45.8%. Streptococcus pneumoniae (17 episodes) and Haemophilus influenzae (15 episodes) were the primary causative organisms. It is noteworthy that two major nosocomial pathogens, Pseudomonas aeruginosa (P. aeruginosa; 5 episodes) and Methicillin-resistant Staphylococcus aureus (MRSA; 2 episodes), were also identified as causative agents of CAP. These two pathogens were isolated from patients with severe underlying diseases and patients who had been repeatedly hospitalized. The incidence of CAP due to P. aeruginosa and MRSA is increasing because patients with respiratory colonization by these nosocomial pathogens are often followed up on an outpatient basis.
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Masaki H, Takasawa N, Yamazaki K. Human movement-related brain potentials preceding voluntary movements in different arousal states monitored with skin potential level. Percept Mot Skills 2000; 90:299-306. [PMID: 10769914 DOI: 10.2466/pms.2000.90.1.299] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The present study investigated the readiness potential (RP) preceding a brisk extension of the right middle finger during different arousal states as monitored by skin potential level (SPL). The late component of the readiness potential in the medium arousal state was significantly larger than those in the low and high arousal states. This finding indicates that the RP waveform may vary as a function of arousal states, suggesting the inverse U-shaped relationship proposed in studies of the contingent negative variation.
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Ishii K, Kubo A, Kusakabe K, Murata H, Masaki H, Horiike S, Hayashi A, Hara Y. [Evaluation of clinical utility of 123I-MIBG scintigraphy in localization of tumors of sympathetic and adrenomedullary origin--a report of multicenter phase III clinical trials]. KAKU IGAKU. THE JAPANESE JOURNAL OF NUCLEAR MEDICINE 2000; 37:43-59. [PMID: 10714067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Phase III clinical study was performed to evaluate clinical utility of 123I-MIBG in the localization of tumors in 48 patients with tumors of sympathetic and adrenomedullary origin, diagnosed or strongly suspected. Sixteen patients had pheochromocytoma, 23 had neuroblastoma, 7 had medullary carcinoma of the thyroid, and 2 had Sipple syndrome. In 3 out of 48 patients, 123I-MIBG scintigraphy was performed twice. The clinical utility of 123I-MIBG was evaluated in 50 cases. Out of 140 lesions, 123I-MIBG scintigraphy demonstrated 51 true positive, 79 true negative, 1 false positive, and 2 false negative. Seven lesions were not evaluable. Sensitivity was 96.2%, Specificity was 98.8%, and Accuracy was 97.7%. An acquisition between 4 hrs and a day after injection was adequate for tumor detection. Neither adverse reactions nor abnormal laboratory findings were noted in relation to 123I-MIBG injections. Our study indicates that 123I-MIBG is a safe and useful radiotracer for visualization and localization of tumors of sympathetic and adrenomedullary origin.
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Masaki H. [Recent trends in radiation therapy for pediatric cancer]. NIHON IGAKU HOSHASEN GAKKAI ZASSHI. NIPPON ACTA RADIOLOGICA 1999; 59:844-52. [PMID: 10655709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
A recent strategy in the treatment of pediatric cancer is the "total cell kill", in which the main part of therapy depends on intensive, aggressive chemotherapy with or without bone marrow transplantation. Radiotherapy, like surgery, plays a role in local treatment. Recent progress in therapy has permitted cures even of patients with advanced cancer. Disease-free patients should have the same quality of life as that of healthy children of the same sex and age. Therefore, both saving the patient's life and providing him or her with a good quality of life are important in treatment policy. To obtain these goals, radiation therapy has been included in combined multi-modality therapy for the management of pediatric cancer. Other important concerns are to reduce the radiation dose and determine the timing of radiation therapy.
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Nishida T, Nakamura A, Masaki H, Uozumi T. Transcriptional regulation of the Bacillus ohbensis cyclodextrin glucanotransferase gene in B. subtilis. Biosci Biotechnol Biochem 1999; 63:1902-9. [PMID: 10635555 DOI: 10.1271/bbb.63.1902] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The expression of the cyclodextrin glucanotransferase (CGTase) gene (cgt) of Bacillus ohbensis, when introduced into an alpha-amylase-defective strain of B. subtilis on a multicopy plasmid, pHY300PLK, was induced in the presence of starch and was subject to catabolite repression by glucose as well as in the original strain, B. ohbensis. We constructed a cgt'::'lacZ translational fusion to study the expression in B. subtilis, and this construct was confirmed to be subject to both starch induction and catabolite repression. In order to define the region involved in the regulation of the cgt gene, a series of cgt'::'lacZ gene with various lengths of deletion in the promoter region was constructed on pHY300PLK. DNA regions responsible for starch induction and catabolite repression by glucose could be separated in the deletion experiment. Primer extension analysis showed that the catabolite repression was controlled at the initiation of transcription, while the starch induction is likely to be controlled by a transcriptional termination-antitermination mechanism.
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Tsutsumi Y, Matsubara H, Masaki H, Kurihara H, Murasawa S, Takai S, Miyazaki M, Nozawa Y, Ozono R, Nakagawa K, Miwa T, Kawada N, Mori Y, Shibasaki Y, Tanaka Y, Fujiyama S, Koyama Y, Fujiyama A, Takahashi H, Iwasaka T. Angiotensin II type 2 receptor overexpression activates the vascular kinin system and causes vasodilation. J Clin Invest 1999; 104:925-35. [PMID: 10510333 PMCID: PMC408562 DOI: 10.1172/jci7886] [Citation(s) in RCA: 446] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/1999] [Accepted: 08/25/1999] [Indexed: 11/17/2022] Open
Abstract
Angiotensin II (Ang II) is a potent vasopressor peptide that interacts with 2 major receptor isoforms - AT1 and AT2. Although blood pressure is increased in AT2 knockout mice, the underlying mechanisms remain undefined because of the low levels of expression of AT2 in the vasculature. Here we overexpressed AT2 in vascular smooth muscle (VSM) cells in transgenic (TG) mice. Aortic AT1 was not affected by overexpression of AT2. Chronic infusion of Ang II into AT2-TG mice completely abolished the AT1-mediated pressor effect, which was blocked by inhibitors of bradykinin type 2 receptor (icatibant) and nitric oxide (NO) synthase (L-NAME). Aortic explants from TG mice showed greatly increased cGMP production and diminished Ang II-induced vascular constriction. Removal of endothelium or treatment with icatibant and L-NAME abolished these AT2-mediated effects. AT2 blocked the amiloride-sensitive Na(+)/H(+) exchanger, promoting intracellular acidosis in VSM cells and activating kininogenases. The resulting enhancement of aortic kinin formation in TG mice was not affected by removal of endothelium. Our results suggest that AT2 in aortic VSM cells stimulates the production of bradykinin, which stimulates the NO/cGMP system in a paracrine manner to promote vasodilation. Selective stimulation of AT2 in the presence of AT1 antagonists is predicted to have a beneficial clinical effect in controlling blood pressure.
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MESH Headings
- Actins/genetics
- Amiloride/pharmacology
- Angiotensin II/pharmacology
- Animals
- Aorta/physiology
- Blood Pressure/physiology
- Bradykinin/analogs & derivatives
- Bradykinin/pharmacology
- Bradykinin/physiology
- Bradykinin Receptor Antagonists
- Cell Membrane/physiology
- Cyclic GMP/metabolism
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiology
- Imidazoles/pharmacology
- Kinins/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- NG-Nitroarginine Methyl Ester
- Promoter Regions, Genetic
- Pyridines/pharmacology
- Receptor, Angiotensin, Type 1
- Receptor, Angiotensin, Type 2
- Receptors, Angiotensin/deficiency
- Receptors, Angiotensin/genetics
- Receptors, Angiotensin/physiology
- Recombinant Fusion Proteins/metabolism
- Tunica Media/physiology
- Vasoconstriction
- Vasodilation/drug effects
- Vasodilation/physiology
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Gori AH, Ahmed K, Martinez G, Masaki H, Watanabe K, Nagatake T. Mediation of attachment of Burkholderia pseudomallei to human pharyngeal epithelial cells by the asialoganglioside GM1-GM2 receptor complex. Am J Trop Med Hyg 1999; 61:473-5. [PMID: 10497993 DOI: 10.4269/ajtmh.1999.61.473] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Melioidosis is the term given to any infection caused by Burkholderia pseudomallei. This bacteria is one of the important causative agents of life-threatening pulmonary infections in the tropical and subtropical areas. The initiation of respiratory infections is attachment of this bacteria to pharyngeal cells. The precise mechanism of attachment of B. pseudomallei is not known. In this study, we found that asialoganglioside GM1 at concentrations of 25, 12.5, and 5 microg/ml significantly decreased the attachment of B. pseudomallei strain Sp-186 in a dose-dependent manner. On the other hand, asialoganglioside GM2 decreased the attachment of B. pseudomallei, but only at a concentration of 25 microg/ml. At a concentration of 1 mg/ml, glucose, N-acetyl-galactosamine, and galactose caused a significant decrease in attachment. However, at concentrations of 250 microg/ml, no decrease in attachment was observed in B. pseudomallei treated with these carbohydrates. Mannose and fucose at concentrations of 1 mg/ml had no effects on the inhibition of attachment of B. pseudomallei. Four other isolates of B. pseudomallei showed a significant decrease in attachment after treatment with asialoganglioside GM1. We conclude that asialogangliosides GM1 and GM2 are part of the receptor complex for B. pseudomallei on human pharyngeal epithelial cells.
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Fujiyama A, Mori Y, Yamamoto S, Iba O, Kurihara H, Masaki H, Yonemoto T, Nagata T, Umeda Y, Yasumizu R, Ikehara S, Inada M, Matsubara H, Iwasaka T. Multiple spontaneous small bowel perforations due to systemic cholesterol atheromatous embolism. Intern Med 1999; 38:580-4. [PMID: 10435365 DOI: 10.2169/internalmedicine.38.580] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A-65-year-old man was admitted for coronary and peripheral angiography to evaluate angina pectoris and peripheral vascular disease. Following angiography, he suffered from blue toes, livedo reticularis and progressive renal failure. The patient's condition continued to deteriorate, including the development of malnutrition. Four months later he suddenly developed panperitonitis, went into shock and died. The autopsy verified multiple perforations of the small bowel with disseminated cholesterol atheromatous embolism. The other organs including kidney were also invaded by atheroembolism. This was a rare case of multiple spontaneous perforations of small bowel due to systemic cholesterol atheromatous embolism.
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Masaki H, Okano Y, Sakurai H. Generation of active oxygen species from advanced glycation end-products (AGEs) during ultraviolet light A (UVA) irradiation and a possible mechanism for cell damaging. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1428:45-56. [PMID: 10366759 DOI: 10.1016/s0304-4165(99)00056-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Advanced glycation end-products (AGEs) have been reported to be accumulated in dermal skin. However, the role of AGEs in the photoaging of human skin remains unknown, and for this reason, we have examined the interaction between AGEs and ultraviolet A light (UVA) from both the chemical and biological aspects. Previously, we reported that exposing human dermal fibroblasts to UVA in the presence of AGEs that were prepared with bovine serum albumin (BSA) decreased the cell viability due to superoxide anion radical s (.O2(-)) and hydroxyl radicals (.OH) generated by AGEs under UVA irradiation, and active oxygen species are detected with ESR spin-trapping. To identify the active oxygen species in detail and to clarify the cell damaging mechanism, we performed several experiments and the following results were obtained. (1) In ESR spin-trapping, by addition of dimethyl sulfoxide and superoxide dismutase, ESR signals due to .O2(-) -derived DMPO-OOH and .OH-derived DMPO-OH adducts, respectively, were detectable. (2) UVA-irradiated AGEs elevated the lipid peroxide levels in both fibroblasts and liposomes. But the peroxidation in liposomes was inhibited by addition of deferoxamine. (3) Survival of fibroblasts exposed to UVA in the presence of AGEs was elevated by addition of deferoxamine. And finally, (4) survival of fibroblasts was found to be regulated by the level of H2O2. On the basis of these results, we propose a possible mechanism in which AGEs under UVA irradiation generate active oxygen species involving .O2(-), H2O2, and .OH, and the .OH species plays a harmful role in promoting cell damage.
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70
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Takashima S, Nakamura A, Hidaka M, Masaki H, Uozumi T. Isolation and characterization of the actin gene from the cellulolytic fungus Humicola grisea and analysis of transcription levels of actin and cellulase genes. Biosci Biotechnol Biochem 1999; 63:1091-5. [PMID: 10427696 DOI: 10.1271/bbb.63.1091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An actin gene was isolated from the cellulolytic fungus Humicola grisea. The gene structure, which has 5 introns in the coding region, is similar to those of the so far cloned fungal actin genes. But there are some differences in intron sizes and codon usage. Transcription levels of actin and cellulase genes were also investigated.
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71
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Moriguchi Y, Matsubara H, Mori Y, Murasawa S, Masaki H, Maruyama K, Tsutsumi Y, Shibasaki Y, Tanaka Y, Nakajima T, Oda K, Iwasaka T. Angiotensin II-induced transactivation of epidermal growth factor receptor regulates fibronectin and transforming growth factor-beta synthesis via transcriptional and posttranscriptional mechanisms. Circ Res 1999; 84:1073-84. [PMID: 10325245 DOI: 10.1161/01.res.84.9.1073] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The signaling cascade elicited by angiotensin II (Ang II) resembles that characteristic of a growth factor, and recent evidence indicates transactivation of epidermal growth factor receptor (EGF-R) by G protein-coupled receptors. Here, we report the involvement of EGF-R in Ang II-induced synthesis of fibronectin and transforming growth factor-beta (TGF-beta) in cardiac fibroblasts. Ang II stimulated fibronectin mRNA levels dose dependently, with a maximal increase (approximately 5-fold) observed after 12 hours of incubation. Fibronectin synthesis induced by Ang II or calcium ionophore was completely abolished by tyrosine kinase inhibitors and intracellular Ca2+ chelating agents. Ang II-induced fibronectin mRNA was not affected by protein kinase C inhibitors or protein kinase C depletion, whereas specific inhibition of EGF-R function by a dominant negative EGF-R mutant and tyrphostin AG1478 abolished induction of fibronectin mRNA. We isolated the rat fibronectin gene, including the 5'-flanking region, and found that the activator protein-1 (AP-1) binding site present in the promoter region was responsible for the Ang II responsiveness of this gene. A gel retardation assay revealed the binding of nuclear protein to the AP-1 site, which was supershifted with anti-c-fos and anti-c-jun but not anti-activating transcription factor (ATF)-2 antibodies. Conditioned medium from Ang II-treated cells contained TGF-beta bioactivity, and addition of neutralizing TGF-beta antibody modestly (46%) inhibited induction of fibronectin. Ang II-induced synthesis of TGF-beta was also abolished by inhibition of EGF-R function. The effect of TGF-beta was exerted by stabilizing fibronectin mRNA without affecting the promoter activity and required de novo protein synthesis. We concluded that Ang II-induced expression of fibronectin and TGF-beta is mediated by downstream signaling of EGF-R transactivated by Ca2+-dependent tyrosine kinase and that Ang II-induced fibronectin mRNA expression is regulated by 2 different mechanisms, which are transcriptional control by binding of the c-fos/c-jun complex to the AP-1 site and posttranscriptional control by mRNA stabilization due to autocrine or paracrine effects of TGF-beta. Thus, this study suggests that the action of Ang II on extracellular matrix formation should be interpreted in association with the EGF-R signaling cascade.
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72
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Kohda E, Saeki M, Nakano M, Masaki H, Ogawa K, Nirasawa M, Hiramatsu K. Congenital absence of the portal vein in a boy. Pediatr Radiol 1999; 29:235-7. [PMID: 10199899 DOI: 10.1007/s002470050580] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Congenital absence of the portal vein (CAPV) is a malformation that is generally thought to be limited to females. We encountered an 11-year-old boy with this malformation. In 17 previously reported cases of CAPV, 2 were male. Three male patients, including our case, were Abernethy type Ib malformation. They had no associated liver tumour and two had no additional congenital abnormality. Conversely, 13 of the 15 female patients had congenital abnormalities and 6 had liver mass lesions.
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73
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Takashima S, Nakamura A, Hidaka M, Masaki H, Uozumi T. Molecular cloning and expression of the novel fungal beta-glucosidase genes from Humicola grisea and Trichoderma reesei. J Biochem 1999; 125:728-36. [PMID: 10101286 DOI: 10.1093/oxfordjournals.jbchem.a022343] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A novel fungal beta-glucosidase gene (bgl4) and its homologue (bgl2) were cloned from the cellulolytic fungi Humicola grisea and Trichoderma reesei, respectively. The deduced amino acid sequences of H. grisea BGL4 and T. reesei BGL2 comprise 476 and 466 amino acids, respectively, and share 73.1% identity. These beta-glucosidases show significant homology to plant beta-glucosidases belonging to the beta-glucosidase A (BGA) family. Both genes were expressed in Aspergillus oryzae, and the recombinant beta-glucosidases were purified. Recombinant H. grisea BGL4 is a thermostable enzyme compared with recombinant T. reesei BGL2. In addition to beta-glucosidase activity, recombinant H. grisea BGL4 showed a significant level of beta-galactosidase activity, while recombinant T. reesei BGL2 showed weak beta-galactosidase activity. Cellulose saccharification by Trichoderma cellulases was improved by the addition of recombinant H. grisea BGL4.
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74
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Takahashi H, Oishi K, Masaki H, Aso N, Minematsu T, Minamishima Y, Nagatake T. [An autopsy case of AIDS complicated with cytomegalovirus infection and multiple Kaposi's sarcoma]. KANSENSHOGAKU ZASSHI. THE JOURNAL OF THE JAPANESE ASSOCIATION FOR INFECTIOUS DISEASES 1999; 73:351-5. [PMID: 10356894 DOI: 10.11150/kansenshogakuzasshi1970.73.351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cutaneous Kaposi's sarcoma (KS) is a well-known complication of the acquired immunodeficiency syndrome. KS in the internal organs, however, is rare in Japan. We present here a 33-years-old Japanese homosexual man who had AIDS complicated with cytomegalovirus (CMV) infection and KS. He was found to be HIV-seropositive, when he was 31-years-old. He visited our hospital in June 1996 because of high fever. The peripheral blood CD4+ lymphocyte counts were 2 per cubic millimeter, and CMV antigenemia was noted (p65 antigen positive cells; 240/50,000 white blood cells). Thereafter he was successfully treated with parental ganciclovir. On admission, some brown-colored flat nodules were found on the skin, and the diagnosis of KS was made by skin biopsy. We administrated human chorionic gonadotropin (hCG) for the treatment of KS, but had no clinical response. In September 1996, he complained of severe cough, shortness of breath, and vomiting. A chest radiogram showed nodular lesions and pleural effusion in bilateral lungs. A computed tomography of his chest also revealed nodular and linear densities distributed along the bronchovascular bundles. The ultrasonic examination of his abdomen revealed a duodenal nodule. Both nodules in the lungs and duodenum were proved to be KS based on the autopsy findings. Intranuclear inclusionbodies pathognomonic for CMV infections were detected in the stomach and the colon.
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75
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Ogawa T, Tomita K, Ueda T, Watanabe K, Uozumi T, Masaki H. A cytotoxic ribonuclease targeting specific transfer RNA anticodons. Science 1999; 283:2097-100. [PMID: 10092236 DOI: 10.1126/science.283.5410.2097] [Citation(s) in RCA: 145] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The carboxyl-terminal domain of colicin E5 was shown to inhibit protein synthesis of Escherichia coli. Its target, as revealed through in vivo and in vitro experiments, was not ribosomes as in the case of E3, but the transfer RNAs (tRNAs) for Tyr, His, Asn, and Asp, which contain a modified base, queuine, at the wobble position of each anticodon. The E5 carboxyl-terminal domain hydrolyzed these tRNAs just on the 3' side of this nucleotide. Tight correlation was observed between the toxicity of E5 and the cleavage of intracellular tRNAs of this group, implying that these tRNAs are the primary targets of colicin E5.
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MESH Headings
- Anticodon/metabolism
- Bacterial Proteins/biosynthesis
- Bacterial Proteins/genetics
- Bacterial Proteins/pharmacology
- Base Sequence
- Cloning, Molecular
- Colicins/genetics
- Colicins/metabolism
- Colicins/pharmacology
- Escherichia coli/drug effects
- Escherichia coli/metabolism
- Escherichia coli Proteins
- Guanine/analogs & derivatives
- Guanine/analysis
- Molecular Sequence Data
- RNA, Bacterial/chemistry
- RNA, Bacterial/metabolism
- RNA, Ribosomal, 16S/metabolism
- RNA, Transfer, Amino Acid-Specific/chemistry
- RNA, Transfer, Amino Acid-Specific/metabolism
- RNA, Transfer, Asn/chemistry
- RNA, Transfer, Asn/metabolism
- RNA, Transfer, Asp/chemistry
- RNA, Transfer, Asp/metabolism
- RNA, Transfer, His/chemistry
- RNA, Transfer, His/metabolism
- RNA, Transfer, Tyr/chemistry
- RNA, Transfer, Tyr/metabolism
- Ribonucleases/genetics
- Ribonucleases/metabolism
- Ribonucleases/pharmacology
- Ribosomes/metabolism
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