Biomedical subjects

T Masuda

Publications and source records attributed to T Masuda.

At least 253 records · Page 14Linked to original sources

PubMed1996

Cloning and detection of the hemolysin gene of Vibrio anguillarum.

A 5 kb DNA fragment encoding a hemolysin was cloned from the fish pathogenic bacterium Vibrio anguillarum using the cosmid vector charomid9-36. An open reading frame of the hemolysin gene (VAH1) was 2253 bp and corresponded to a protein of 751 amino acid residues. The deduced amino acid sequence of the VAH1 gene and the previously reported Vibrio cholerae EI Tor hemolysin, V. vulnificus cytolysin-hemolysin, Aeromonas hydrophila AHH1 hemolysin, and A. salmonicida ASH4 hemolysin showed a significant degree of sequence homology, and the overall amino acid identities were 57.3%, 25.8%, 46.2%, and 43.7%, respectively. DNA hybridization analysis under high-stringent conditions using VAH1 as a probe, demonstrated that VAH1 hybridized with 25 out of 28 strains of V. anguillarum including serotypes A to I, but did not hybridize with other species of Vibrio, A. hydrophila or A. salmonicida. The targeted DNA fragment of VAH1 was successfully amplified from V. anguillarum-infected fish tissues by PCR.

Amino Acid Sequence↗

PubMed1996

Long-term follow-up of coronary artery dissection due to blunt chest trauma with spontaneous healing in a young woman.

We report a previously healthy 17-year-old woman who experienced coronary artery dissection with an acute transmural anterior myocardial infarction and myocardial contusion following blunt chest trauma in a motorcycle accident. A chest roentgenogram on admission was normal, and an electrocardiogram showed an acute transmural anterior myocardial infarction with complete right-bundle-branch block. A 2D echocardiogram revealed an akinesis of the anterior wall and a hypokinesis of the posterior wall in the left ventricle. Initial coronary angiography demonstrated severe stenosis with delayed antegrade filling in the proximal left anterior descending artery. Technetium-99m pyrophosphate myocardia scintigraphy demonstrated diffuse tracer uptake in the left ventricular wall. Follow-up coronary angiography performed 1 year after the accident showed a minor stenosis without any filling defects. We describe long-term follow-up of the coronary artery dissection following blunt chest trauma with spontaneous healing.

Adolescent↗

PubMed1996

Effect of ethanol on mouse hepatitis virus-induced cytotoxicity.

The effect of ethanol on cells infected with mouse hepatitis virus (MHV) was investigated. After MHV infection of competent cells, NCTC1469, ethanol was added to the culture at various concentrations, and the viability of cells was measured using 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide. To examine the possible involvement of the ethanol metabolite, acetaldehyde, alcohol dehydrogenase activity was measured in NCTC1469 cells. Ethanol alone did not show cytotoxicity against NCTC1469 cells at concentrations from 0.125% to 2%. After infection with MHV, the viability of cells decreased, and this decrease was further enhanced, dose-dependently, by the addition of ethanol. The activity of alcohol dehydrogenase in the cells was below the detectable level. The same phenomena were also demonstrated in cells infected with influenza virus and Herpes simplex virus. These results demonstrate that ethanol enhances MHV-mediated cytotoxicity; this exacerbation of cytotoxicity by ethanol is suggested to be an effect common to cytopathic virus-infected cells.

Analysis of Variance↗

PubMed1996

Improvement of glucose tolerance with immunomodulators on type 2 diabetic animals.

Cytokine-inducers prevent insulin-dependent diabetes mellitus (IDDM) in animal models. We extend this therapy to non-insulin-dependent diabetes mellitus (NIDDM), because it was reported that diabetes of KK-Ay mice, a model for NIDDM, was recovered by allogenic bone-marrow transplantation that also prevented IDDM in animal models. An i.p. or i.v. injection of streptococcal preparation (OK-432) lowered fasting blood glucose (FBG) levels and markedly improved glucose tolerance test (GTT) in KK-Ay mice for more than 32 h regardless of the glucose loading routes (oral, i.v. or i.p.), while an i.v. injection of BCG improved FBG and GTT for more than 4 wks without body weight loss. The improvement of FBG and GTT with OK-432 was brought about in other NIDDM animals, GK rats and Wistar fatty rats. Among various cytokines possibly induced by OK-432 and BCG, IL-1 alpha, TNF alpha and lymphotoxin significantly improved FBG and GTT in KK-Ay mice, whereas IL-2 and IFN gamma did not. There were no differences between the OK-432-treated KK-Ay mice and control in histology of the pancreas, degree of insulin-induced decrease in blood glucose levels, and muscle glycogen synthase activities. As to insulin secretion, there is a tendency that the OK-432-treatment less that 1 week did not affect insulin levels during GTT, whereas the treatment more than 2 weeks increased the insulin levels. Thus, cytokine-inducers improved FBG and glucose tolerance of NIDDM animals probably via cytokines. The results imply a role of the cytokines in glucose tolerance of NIDDM, although precise immune and metabolic mechanisms remain to be elucidated.

Adjuvants, Immunologic↗

PubMed1996

A possible involvement of Fas-Fas ligand signaling in the pathogenesis of murine autoimmune gastritis.

BACKGROUND & AIMS: A Th1 clone, II-6, established from an autoimmune gastritis BALB/c mouse that underwent thymectomy 3 days after birth, recognized a 15 mer peptide constructing the alpha subunit of H+, K(+)-adenosine triphosphatase as antigen and induced gastritis in nu/nu mice by adoptive transfer. The aim of this study was to examine the molecular mechanism of target (parietal cells) destruction in either thymectomized or II-6 cell-transferred nu/nu mice. METHODS: Expression of Fas, major histocompatibility complex class II, and intercellular adhesion molecule 1 molecules on the gastric mucosa of these mice were immunohistochemically examined. In situ DNA fragmentation in these thymectomized or nu/nu mice was tested by the terminal deoxynucleotidyl transferase-mediated digoxigenin-deoxyuridine triphosphate nick end label (TUNEL) method. Moreover, activity of II-6 cells to induce apoptosis was tested by using the 15 mer peptide-pulsed B lymphoma cells, A20.2J, as the target. RESULTS: A portion of parietal cells in gastritis-bearing thymectomized or nu/nu mice at an early stage expressed Fas, major histocompatibility complex class II, and intercellular adhesion molecule 1 molecules and was TUNEL positive. Fas-ligand message was induced on activated II-6 cells and caused DNA fragmentation of the antigen-pulsed A20.2J cells. CONCLUSIONS: Cognate interaction between Fas antigen on the target and Fas ligand on the effector seems to be one possible mechanism for the target cell destruction in organ-specific autoimmune gastritis.

Animals↗

PubMed1996

Two regulation points for differentiation in the cell cycle of human megakaryocytes.

To examine the relationship between cell cycle progression and differentiation in megakaryocytes, variances in the cell cycle during PMA (phorbol 12-myristate-13-acetate)-induced differentiation were analysed in synchronized growing CMK cells. The cells stimulated with PMA in early S phase showed cell cycle arrest in G2 phase. In addition, the cells stimulated with PMA in early G1 phase showed cell cycle arrest in late G1. The expression of gpIIb/IIIa, megakaryocytic differentiation marker, was markedly induced in G2 phase when the cells were stimulated in early S phase, and was also induced in late G1 phase when cells were stimulated in early G1 phase. Therefore, the induction of gpIIb/IIIa expression seems to be associated with cell cycle blockage in both G2 and late G1. Expression of the transcription factor GATA-1 in cells stimulated in early S phase was much higher than that in controls at G2 phase. Furthermore, GATA-1 expression in cells stimulated in early G1 tended to be higher than that in controls at late G1. These periods corresponded to the time that the cell cycle arrest and gpIIb/IIIa expression were induced by PMA. These results suggest that the cell cycle in human megakaryocytic lineage cells may have two regulation points for differentiation.

Base Sequence↗

PubMed1996

Cloning of variable regions of an antibody that reacts with the soluble fraction of human liver cells and its possible value in chronic liver disease.

A gene encoding the variable regions of the heavy and light chains of a mouse monoclonal antibody designated H2, which specifically reacts with human liver cells, was cloned into a phagemid vector. The clone of the variable region was designed to be expressed as a separate protein, the structure of which is the same as that of the mouse antibody. The cloned phage protein specifically reacted with anti-idiotypic antibodies produced in rabbits against the original mouse antibody, and this reaction was specifically blocked by the original antibody. The soluble protein, expressed as a fusion protein, was detected as a single 30-kd band on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and specifically bound to an anti-H2 idiotypic antibody as determined by Western blot analysis. Sera of patients with various diseases were assayed for antibodies to anti-H2 by sandwich enzyme-linked immunosorbent assay (ELISA). Only sera from patients with chronic liver disease reacted strongly. This binding was specifically blocked by the cloned soluble protein. The nucleotide sequences of the variable regions were determined by the dideoxy chain-termination method, and the sequences were approximately 95% identical to those of other mouse immunoglobulins. These findings suggest that a human antibody with the same idiotype as a mouse monoclonal antibody that reacts with human liver cells, can be detected in patients with chronic liver disease, suggesting that autoimmunity may be partly responsible for these diseases.

Adult↗

PubMed1996

Kupffer cell-mediated cytotoxicity against hepatoma cells occurs through production of nitric oxide and adhesion via ICAM-1/CD18.

Rat Kupffer cell (KC)-mediated cytotoxicity against both the syngeneic hepatoma cell line AH70 and hepatocytes was evaluated by changes in mitochondrial function, and the possible role of ICAM-1/CD18 in the interaction between the cells was studied. Rhodamine 123 fluorescence, a marker of the mitochondrial membrane potential, decreased in AH70 cells after co-culture with CK, while that in hepatocytes was unchanged by co-culture. This decrease was blocked by anti-ICAM-1 anti-CD18 and the inhibition of nitric oxide synthesis. Cytometric studies demonstrated that ICAM-1 expression on AH70 cells increased after addition of IFN-gamma, IL-1beta, tumor necrosis factor (TNF)-alpha or KC, while in hepatocytes ICAM-1 was not increased. Anti-ICAM-1 pretreatment inhibited the increase in ICAM-1 expression and the decrease in rhodamine 123 fluorescence on AH70 cells after co-culture with KC. CD18 on KC was increased only after co-culture with AH70. TNF-alpha but not IFN-gamma was detected in the supernatant of co-culture between KC and AH70 cells, and this production was partially inhibited by anti-ICAM-1 and anti-CD18. The activity of inducible nitric oxide synthase in Kupffer cells and the levels of nitrites and nitrates in the co-culture supernatant increased over time, and this increase was attenuated either by addition of NO synthesis inhibitors, anti-ICAM-1 or anti-CD18. These results indicate that the rat KC causes mitochondrial dysfunction in cancer cells via the production of NO and cell-to-cell adhesion via ICAM-1/CD18 has an important role in this cytotoxic process.

Animals↗

PubMed1996

Expression of the puf operon in an aerobic photosynthetic bacterium, Roseobacter denitrificans.

The effects of oxygen and light on the expression of the puf operon were investigated in Roseobacter denitrificans in a comparison with those in Rhodobacter sphaeroides. In darkness, the levels of the total puf mRNA in Ros. denitrificans were about 1.3 times those in Rb. sphaeroides at low concentrations of oxygen, reflecting the accumulation of bacteriochlorophyll and carotenoids. The oxygen tension, up to 94% saturation of dissolved oxygen, did not affect the levels of the total puf transcripts in Ros. denitrificans, whereas those in Rb. sphaeroides were reduced to 55% of the maximum level even at 50% saturation. Four puf-specific transcripts were detected: a 0.5-kb transcript was the most abundant; 1.2-kb and 1.9-kb transcripts accumulated at low levels; and a 3.5-kb transcript accumulated at very low levels under all conditions tested. The levels of the individual transcripts were barely affected by molecular oxygen. An S-1 nuclease protection assay revealed that the 0.5-kb transcript encoded the LHI-alpha and LHI-beta subunits (pufBA), the 1.2-kb transcript encoded puf-BA and part of pufL, and the 1.9-kb transcript encoded pufBAL and part of pufM. It was not clear whether the 3.5-kb transcript encoded the entire pufBALM and the gene for the polypeptide moiety of cytochrome c. The difference in levels between the 0.5-kb transcript and the other transcripts (1.2 kb, 1.9 kb, and 3.5 kb) was presumed to be due to the presence of several stem-loop structures at the 3' terminus of the 0.5-kb transcript which acted as terminators of transcription and, possibly, as protection against nucleolytic digestion. Light inhibited the expression of the puf operon in Ros. denitrificans more effectively than that in Rb. sphaeroides. The insensitivity to oxygen, as well as the sensitivity to light, of the expression of the puf operon in Ros. denitrificans, which was different from that in Rb. sphaeroides, seemed to represent a mode of adaptation that allowed the former cells to avoid photodynamic damage by light under highly aerobic conditions.

Bacteria↗

PubMed1996

A transcription factor with a leucine-zipper motif involved in light-dependent inhibition of expression of the puf operon in the photosynthetic bacterium Rhodobacter sphaeroides.

In the purple nonsulfur photosynthetic bacterium Rhodobacter sphaeroides the synthesis of components of the photosystem is regulated in response to oxygen tension and light intensity. We have purified and cloned a trans-acting protein (SPB) that binds to the promoter region of the puf operon, which encodes the apoproteins of light-harvesting complex I and the reaction center. The SPB was composed of a single polypeptide with an apparent molecular mass of 15.0 kDa. The nucleotide sequence of the spb gene was determined. The gene encoded 104 amino acid residues, which correspond to a molecular mass of 11.5 kDa. SPB exhibited 53% homology to HvrA in Rhodobacter capsulatus. The deduced amino acid sequence indicated that SPB contained a region with homology to the leucine-zipper motif of c-JUN, a transcription factor in eukaryotes, and SPB also had a DNA-binding domain on the amino-terminal side of the leucine-zipper motif. The leucine-zipper motif of SPB might contribute to the formation of a dimer. Northern analysis indicated that spb was constitutively and monocistronically transcribed in R. sphaeroides, irrespective of growth conditions. Structural and functional differences between SPB and HvrA are discussed.

Amino Acid Sequence↗

PubMed1996

Phosphorylation of a protein (pp56) is related to the regeneration of rice cultured suspension cells.

Short-term cultured suspension cells of rice (Oryza sativa L.) are capable of regeneration, but not in long-term culture. For clarification of the mechanism of regeneration, protein phosphorylation in short-term and long-term cultured suspension cells was compared by two dimensional-polyacrylamide gel electrophoresis. A 56 kDa protein having an isoelectric point of 4.5 was phosphorylated in vitro in short-term cultured suspension cells, but was not phosphorylated after regeneration. This protein in long-term cultured suspension cells remained phosphorylated after transfer to the regeneration medium. However, using an antibody raised against this protein from short-term cultured suspension cells, it was always detected in long-term and short-term cultured suspension cells after transfer to the regeneration medium. The partial amino acid sequence of the HPLC-purified protein showed homology to a calcium-binding protein from maize. The phosphorylation of the 56 kDa protein (pp56) appears to be associated with the regeneration of cultured rice cells.

Amino Acid Sequence↗

PubMed1996

Differential expression of two hemA mRNAs encoding glutamyl-tRNA reductase proteins in greening cucumber seedlings.

The first committed step of porphyrin synthesis in higher plants is the reduction of glutamyl-tRNA to glutamate 1-semialdehyde. This reaction is catalyzed by glutamyl-tRNA reductase, which is encoded by hemA genes. Two hemA cDNA clones (hemA1 and hemA2) were obtained from cucumber (Cucumis sativus) cotyledons by the PCR and cDNA library screening. They showed significant homology with published hemA sequences. Southern blot analysis of cucumber genomic DNA revealed that these genes are located at different loci and that there is another gene similar to the hemA genes. Accumulation of hemA1 mRNA was detected primarily in cotyledons and hypocotyls of greening cucumber seedlings, whereas that of hemA2 mRNA was detected in all tissues examined. Illumination of cucumber seedlings increased markedly the accumulation of hemA1 mRNA, but it did not induce remarkable changes in that of hemA2 mRNA. These findings suggest that hemA1 mRNA was accumulated in response to the demand of Chl synthesis in photosynthesizing tissues, whereas hemA2 mRNA was expressed in response to the demand of the synthesis of porphyrins other than chlorophylls.

Aldehyde Oxidoreductases↗

PubMed1996

[Invasive amebiasis at an institution for the mentally retarded in Shizuoka Prefecture].

Amebiasis caused by Entamoeba histolytica at an institution for mentally retarded in Shizuoka Prefecture is reported. Five of the 50 patients showed E. histolytica cysts in their stools and 4 were positive serologically. The polymerase chain reaction and restriction fragment length polymorphism revealed that the isolates were pathogenic-type E. histolytica. Epidemiological analysis revealed that the amebic infection was caused by the abnormal behavior of mentally retarded patients. Administration of diloxanide furoate and metronidazole for cyst-carriers eliminated cysts from the stool and lowered the antibody titer.

Adult↗

PubMed1996

[A case of infective endocarditis with purpura and macroscopic hematuria as initial manifestations].

A 44-year-old female admitted to our hospital because of fever, purpura and macroscopic hematuria. She had been diagnosed as having ventricular septal defect (VSD). She noticed purpura with pain on bilateral legs and macroscopic hematuria since September 18, 1994. Three weeks later she also manifested a fever. Physical examination of admission revealed numerous purpura and leg edema. Laboratory data showed macroscopic hematuria, marked anemia (Hb 3.3 g/dl), leukocytosis, azotemia (Cr 2.7 mg/dl) and positive acute phase reactants. Increased serum immune complex level and hypocomplementemia were also found. The diagnosis of allergic purpura was made initially, but positive blood culture of Streptococcus mitis and the detection of vegetation attached to the right ventricular wall near the ostium of the VSD made the definite diagnosis of infective endocarditis (IE). Chemotherapy with PCG was started for two weeks but with no effect. The chemotherapy was altered to panipenem/betamipron with a daily dose of 3 g, Then, her fever fell and purpura, macroscopic hematuria and renal failure gradually disappeared. In this case, the cause of renal manifestations was considered to be immune complex glomerulonephritis. This is the first report of IE with macroscopic hematuria due to immune complex glomerulonephritis.

Acute Kidney Injury↗

PubMed1996

Eosinophil adhesion to cultured airway epithelial cells from guinea pig lungs.

We examined the effects of histamine, tumor necrosis factor-alpha (TNF alpha), interferon-gamma (IFN gamma), indomethacin and dexamethasone on the adherence of eosinophils to airway epithelial cells. Epithelial cells were isolated from guinea pig trachea through enzymatic digestion, and cultured until they showed confluence. Eosinophils were taken by peritoneal lavage from guinea pigs sensitized with horse serum and purified. The adhesion of eosinophils to cultured epithelial cells was examined using 51Cr. The percentage adhesion was obtained by dividing counts per minute of lysed eosinophils adhered to epithelial cells by suspended eosinophils. Histamine significantly increased the adhesion of eosinophils to epithelial cells, while TNF alpha or IFN gamma did not significantly alter the adhesion. Indomethacin significantly inhibited the adhesion of eosinophils to epithelial cells in both nontreated and histamine-induced conditions. Dexamethasone also reduced adhesion, although it did not reach statistical significance. These findings indicate that histamine induced eosinophil adherence to airway epithelial cells, suggesting a role of endogenous prostaglandins in adherence.

Animals↗

PubMed1996

Surfactant apoprotein-A concentration in airway secretions for the detection of pulmonary oedema.

Patients with cardiogenic pulmonary oedema expectorate foamy sputum containing surfactant, which might be expected to include surfactant apoprotein A (SP-A). SP-A is specific for lung surfactant. We have measured the SP-A concentration in airway secretions to determine whether it is useful in distinguishing pulmonary oedema from other disorders. Samples of sputum and of aspirated airway secretion were obtained from 11 patients with cardiogenic pulmonary oedema, seven patients with clinically stable congestive heart failure, five patients with adult respiratory distress syndrome (ARDS) and 20 control patients (10 intubated) with other respiratory diseases. The samples were used for the measurement of SP-A concentration by a two-site simultaneous immunoassay with monoclonal antibodies against SP-A. SP-A concentrations, measured in samples of sputum and aspirated secretions, depended on the diagnosis of the patients from which they had come. In descending order these samples came from patients with: cardiogenic pulmonary oedema (1324 +/- 197 micrograms.mL-1; n = 33); ARDS (311 +/- 47 micrograms.mL-1; n = 23); clinically stable congestive heart failure (78 +/- 10 micrograms.mL-1; n = 21); and control conditions (3.0 +/- 0.6 micrograms.mL-1; n = 30). Concentrations from disease samples did not overlap with controls. In samples from patients with cardiogenic pulmonary oedema, the SP-A concentration correlated with mean pulmonary capillary wedge pressure (PCWP) (p < 0.001; n = 39). These findings indicate that the measurement of the surfactant apoprotein A concentration in airway secretions may be useful for the detection of pulmonary oedema.

Aged↗

PubMed1996

Studies on agents with vasodilator and beta-blocking activities. IV.

A series of novel pyridazinone derivatives (II) having a phenoxypropanolamine moiety was synthesized. Their hypotensive and beta-blocking activities were evaluated after intravenous administration of the compounds to anesthetized rats. Among them, the 5-chloro-2-cyanophenoxy derivative (29) showed the promising dual activities and was selected for further studies.

Adrenergic beta-Antagonists↗

PubMed1996

Simple method for quantifying disorientation of myofiber in endomyocardial biopsy specimens using an image analyzer.

The disarray of cardiac myofibers was morphometrically evaluated in biopsy specimens, obtained from patients with hypertrophic cardiomyopathy (HCM), hypertensive heart disease (HHD), chronic phase myocarditis and controls. Microphotographs of myocardium were taken at a final magnification of x 250. For each segment of myofibers, the longitudinal direction was traced on a transparent sheet, and the angle of the traced direction to the baseline was measured by an image analyzer. The standard deviation of the angles was used as an indicator of myofiber disarray. The histograms showed a narrow variation in the control group, but a wide variation in the patients with HCM, HHD and chronic phase myocarditis. The mean value of standard deviations of myofiber angles in HCM was significantly larger than that in the other groups. In HCM, the standard deviation of the myofiber angle proved to correlate positively with IVST/LVPWT (the thickness ratio of interventricular septum to the left ventricular posterior wall) (r = 0.70, p < 0.05), and also with LVEDP (left ventricular end-diastolic pressure) (r = 0.66, p < 0.05). In conclusion, the image analyzer serves as a simple and useful tool in quantifying the disorientation of myofibers and estimating the correlation between the histological and clinical findings.

Adult↗