Biomedical subjects

S Tada

Publications and source records attributed to S Tada.

At least 19 recordsLinked to original sources

PubMed1992

[MR imaging of degenerative lumbar disc disease emphasizing on signal intensity changes in vertebral body].

Magnetic resonance imaging was performed in 400 patients with degenerative disc disease. Signal changes and their sites in the vertebral body were classified and referred to narrowing of the intervertebral disc space. MR findings were compared with those of plain roentgenograms of the lumbar spine. Signal changes in the vertebral body were noted in 83 cases (102 vertebral bodies). Low-intensity abnormality on both T1- and T2-weighted images (WI) was the most common finding, and was most frequently seen at the end plate and/or the angle. These changes were correlated with narrowing of the disc space and osteosclerosis on the plain roentgenogram of the lumbar spine. Signal changes occasionally occurred in the inner region of the vertebral body, and these lesions tended to show a high-intensity abnormality on T1-WI. We conclude that signal changes in degenerative disc disease are not specific, but are sometimes difficult to distinguish from the signal changes in other conditions such as spinal tumor or bone marrow disorder.

Humans↗

PubMed1992

P2 purinoceptor-mediated cyclic AMP accumulation in bovine vascular smooth muscle cells.

Extracellular ATP has been shown to induce intracellular Ca2+ mobilization and adenylate cyclase inhibition via P2 purinoceptors in several species of cells. Now we found that in calf vascular smooth muscle cells the addition of ATP to the medium did not induce inhibition but stimulation of cyclic AMP accumulation, in addition to stimulation of inositol phosphate production. Adenosine and AMP also induced cyclic AMP accumulation but their efficacy was much less than that of ATP. The ATP action was not influenced by the presence of either adenosine deaminase or of an ATP regenerating system, whereas the AMP action was increased by the regenerating system. The results indicate that the cyclic AMP accumulation by ATP is due to ATP itself but neither to adenosine nor to AMP, both of which are produced from ATP. ATP receptor coupled to the cyclic AMP generation was shown to be different from that coupled to phospholipase C based on the difference in the potency order of the receptor agonists and in the sensitivity of P2 receptor agonists to 8-cyclopentyl-1,3-dipropylxanthine (CPX)- and suramin-induced antagonism. We conclude that in the aortic smooth muscle cells a novel P2-type receptor directly coupled to adenylate cyclase activation exists in addition to the previously known P2 receptor linked to phospholipase C activation.

Adenosine Triphosphate↗

PubMed1992

Phosphorylation of the inhibitory guanine-nucleotide-binding protein as a possible mechanism of inhibition by protein kinase C of agonist-induced Ca2+ mobilization in human platelet.

Increases in the intracellular Ca2+ concentration of human platelets caused by receptor agonists, such as thrombin, 9,11-epithio-11,12-methanothromboxane A2 (STA2), platelet-activating factor (PAF) and arginine-vasopressin, were inhibited by prior addition of 12-O-tetradecanoylphorbol 13-acetate (TPA) in time-dependent and concentration-dependent manners. The inhibitions were mostly reversed by staurosporine, and inhibitor of protein kinase C, added 1 min before TPA. Prior treatment of platelets with thrombin or STA2, the efficacious Ca2+ mobilizer, suppressed the increase in the intracellular Ca2+ concentration of the cells to other agonists, but treatment with less efficacious PAF or vasopressin did not. The heterologous receptor desensitizations were also reversed by staurosporine. The antibody, directed against the carboxy-terminal region of the alpha subunits 1 and 2 of the inhibitory guanine-nucleotide-binding proteins (Gi1 alpha and Gi2 alpha), was raised in rabbit and was used to immunoprecipitate Gi alpha in 32P-labeled platelets. The radioactivity was detected in Gi alpha after incubation of 32P-labeled platelets with TPA, thrombin or STA2, but not in the cells incubated with PAF or vasopressin. The time-dependency or concentration-dependency of TPA-induced phosphorylation of Gi alpha was similar to the dependency of its inhibitory action on agonist-induced Ca2+ mobilization. Thus, strong activation of Ca2+/phospholipid-dependent protein kinase C by phorbol ester or agonists of certain Ca(2+)-mobilizing receptors leads to phosphorylation of the alpha subunit of guanine-nucleotide-binding protein, thereby impairing the coupling of the G protein to receptors as a feedback regulatory component of the receptor-triggered intracellular Ca(2+)-mobilizing system.

Alkaloids↗

PubMed1992

Visualization of oxidative processes at the cellular level during neutrophil-mediated cytotoxicity against a human hepatoma cell line, HCC-M.

Human neutrophil-mediated oxidative processes against a human hepatoma cell line, HCC-M, was visualized at the cellular level by using a silicon-intensified target camera and subsequently processing with a computer-assisted digital-imaging processor. Neutrophils were activated by a streptococcal preparation, OK-432. A hydroperoxide-sensitive tracer, dichlorofluorescein diacetate, was loaded in HCC-M and temporal and spatial changes of lipid peroxides in this cell after addition of stimulated neutrophils were analyzed. The luminol-dependent chemiluminescence activity of neutrophils was significantly enhanced and continued for at least 2 hr by stimulation with OK-432, and its activity was shown to be accumulated at the site where a neutrophil attached with HCC-M. The intensity of dichlorofluorescein fluorescence in HCC-M rapidly increased after adding stimulated neutrophils, and their reaction was significantly attenuated by superoxide dismutase. The number of non-viable cells was increased as the dichlorofluorescein fluorescence increase. It is suggested that oxidative stress may play an important role in neutrophil-mediated tumor-cell damage.

Carcinoma, Hepatocellular↗

PubMed1992

Probable occurrence of toxin-susceptible G proteins in the nematode Caenorhabditis elegans.

Pertussis toxin, islet-activating protein (IAP), and cholera toxin ADP-ribosylated 40 kDa and 45 kDa proteins in membrane preparations from Caenorhabditis elegans. Proteins with the same molecular weights were recognized in the same membranes by an antibody that had been raised against a peptide common to alpha-subunits of mammalian alpha beta gamma-heterotrimeric G proteins. The antibody produced immunoprecipitation with the 40 kDa protein 32P-labeled by IAP. A 35 kDa protein immunochemically indistinguishable from the beta-component of mammalian G proteins was also found in C. elegans membranes. The membranes displayed adenylate cyclase activity which was highly sensitive to forskolin and GTP analogues, whose action was antagonized by GDP beta S. Receptor-coupled regulation of adenylate cyclase thus appears to be mediated by mammalian-type G proteins in C. elegans as well.

Adenosine Diphosphate Ribose↗

PubMed1992

High level expression of the synthetic human lysozyme gene in Aspergillus oryzae.

Aspergillus oryzae was transformed with a synthetic gene consisting of a chicken lysozyme signal sequence and a mature human lysozyme (HLY) sequence. The transformants secreted active HLY (about 1.2 mg/l) when the HLY gene was expressed under the control of the Taka-amylase A gene (amyB) promoter. Western blot analysis suggested that the secreted protein was immunoreactive with anti-human lysozyme antibody and the signal peptide was correctly cleavaged off in the A. oryzae transformants. The transcriptional level of the HLY gene was investigated by Northern blot analysis using a probe that was equivalently specific to both the HLY gene and the amyB gene. The HLY gene was expressed at a higher level compared with the amyB gene because of its multi-copy integration. The efficient transcription of the HLY gene suggested that A. oryzae is a promising host for production of heterologous proteins from higher eukaryotes.

Amylases↗

PubMed1992

The anticoagulant effects of ionic and nonionic low-osmolar contrast media in dogs.

RATIONALE AND OBJECTIVES: The anticoagulant effects of ionic and nonionic low-osmolar contrast media were evaluated in vivo. METHODS: The amount of clot deposited on guide wires placed in the femoral vessels of dogs was weighed 30 minutes after the injection of 2 mL/kg of different contrast media. Six dogs were examined after injection of ioxaglate (ioxaglate group), six after injection of iopamidol (iopamidol group), and five after injection of saline (saline group). RESULTS: The mean weights of clot deposited on the guide wires in dogs in the ioxaglate group, the iopamidol group, and saline group were 30.5, 63.1, and 74.2 mg, respectively. The mean weight of clot deposition on the guide wires in the ioxaglate group was significantly less than in the iopamidol and saline groups, whereas there was no statistical difference in the mean weight of clot deposition on the guide wires in the iopamidol and saline groups. CONCLUSIONS: Ioxaglate, a low-osmolar, ionic contrast medium, has a greater anticoagulant effect than a low-osmolar, nonionic contrast agent, such as iopamidol.

Animals↗

PubMed1992

Deletion analysis of the Taka-amylase A gene promoter using a homologous transformation system in Aspergillus oryzae.

The Taka-amylase A gene (amyB) of Aspergillus oryzae is induced by starch or maltose. The molecular mechanism of the induction was investigated using a fusion of the amyB promoter and the Escherichia coli uidA gene encoding beta-glucuronidase (GUS). To identify the region responsible for high-level expression and regulation within the amyB promoter, a series of deletion promoters was constructed and introduced into the A. oryzae met locus by homologous recombination. Deletion of the region between -377 to -290 (the number indicates the distance in base pairs from the translation initiation point (+1) to the deletion end point) significantly reduced of the GUS activity, but slight reduction of the GUS activity was observed in deletions up to -377. Northern blot analysis showed that reduction of the GUS activity depended upon the expression level of the GUS gene. The region between -377 to -290 is suggested to include the sequence required directly for high-level expression and regulation of the amyB gene.

Aspergillus oryzae↗

PubMed1992

Site-directed mutagenesis of catalytic active-site residues of Taka-amylase A.

The cDNA encoding Taka-amylase A (EC.3.2.1.1, TAA) was isolated to identify functional amino acid residues of TAA by protein engineering. The putative catalytic active-site residues and the substrate binding residue of TAA were altered by site-directed mutagenesis: aspartic acid-206, glutamic acid-230, aspartic acid-297, and lysine-209 were replaced with asparagine or glutamic acid, glutamine or aspartic acid, asparagine or glutamic acid, and phenylalanine or arginine, respectively. Saccharomyces cerevisiae strain YPH 250 was transformed with the expression plasmids containing the altered cDNA of the TAA gene. All the transformants with an expression vector containing the altered cDNA produced mutant TAAs that cross-reacted with the TAA antibody. The mutant TAA with alteration of Asp206, Glu230, or Asp297 in the putative catalytic site had no alpha-amylase activity, while that with alteration of Lys209 in the putative binding site to Arg or Phe had reduced activity.

Amylases↗

PubMed1992

Effect of dexamethasone, dimethylsulfoxide and sodium butyrate on a human hepatoma cell line PLC/PRF/5.

The effects of agents which are known to be differentiation inducers on a human hepatoma cell line PLC/PRF/5 were investigated. Dexamethasone (DEX), sodium butyrate (SB) or dimethylsulfoxide (DMSO) were examined. They all reduced cell proliferation but differ from each other in effect on the secretion of alphafetoprotein (AFP) and hepatitis B surface antigen (HBsAg), changes in morphology and RNA transcription. SB changed the cell from polygonal into a fibroblast-like type and decreased AFP secretion. DMSO decreased the cell size and changed AFP secretion in the same manner as SB. DEX changed the cell into a larger size, as well as increased AFP secretion. HBsAg secretion and also HB virus DNA transcription was enhanced by 3 agents. AFP and myc gene transcriptions were reduced by SB but DMSO reduced only AFP. Albumin gene transcription was enhanced by SB and DEX. These results indicate that the decrease of PLC/PRF/5 proliferation is induced through different mechanisms by these 3 agents.

Butyrates↗

PubMed1992

[Studies on IFN-gamma production by peripheral blood mononuclear cells cultured with Candida antigen in asthmatics].

T-cell-derived lymphokine, IFN-gamma, has potent effects on B-cell differentiation and leukotriene C4 production in leukocytes, and inhibits the effect of IL-4 on IgE production. To investigate the role of IFN-gamma in the pathogenesis of bronchial asthma, we examined IFN-gamma production by peripheral blood mononuclear cells cultured with Candida antigen and serum Candida specific IgG1 antibody from 20 asthmatics. The results were as follows: 1) IFN-gamma production in non-atopic severe asthmatics was significantly higher than in healthy subjects, atopic mild and moderate asthmatics, and atopic severe asthmatics (p < 0.05). 2) There was a significant correlation between IFN-gamma production induced by Candida antigen and serum Candida specific IgG1 antibody (r = 0.72, p < 0.01). These results suggest that IFN-gamma may play an important role in the pathogenesis of non-atopic severe bronchial asthma.

Adult↗

PubMed1992

[A case of pulmonary infiltration with eosinophilia (PIE) syndrome induced by Saiboku-To (TJ96). Detection of ECF activity in lymphocytes stimulated with TJ96].

A case of PIE syndrome induced by Saiboku-To (TJ96) is reported. A 56-year-old woman had been treated for intractable bronchial asthma since the age of 42 years. She had a history of PIE syndrome induced by disodium cromoglycate 4 years previously (Jpn. J. Thoracic Disease, 27.1.1989). To reduce the dose of prednisolone for her asthma, administration of TJ96 was started in Dec. 1989. After 5 months of TJ96 treatment, she developed dry cough, fever, and chest pain. Physical findings and laboratory examinations revealed pulmonary infiltrations in the right lung field and severe eosinophilia. Because of suspected drug-induced PIE, TJ96 was stopped and 30 mg/day prednisolone was administered. Her symptoms and laboratory abnormalities subsequently resolved. To confirm the diagnosis of drug-induced PIE syndrome, drug-induced lymphocyte stimulation tests with TJ96 and other drugs were performed. TJ96 significantly induced lymphocyte blastogenesis with a stimulation index of 6.1. Moreover, the supernatant of the incubation mixture of TJ96 and peripheral lymphocytes from the patient showed marked eosinophil chemotactic activity. To our knowledge, there has been no previous report of PIE syndrome induced by TJ96. In addition, this is the first report of the detection of ECF activity in lymphocytes induced by an offending drug in vitro.

Asthma↗

PubMed1992

[Studies of lymphocyte activation on late asthmatic response in adult asthma].

Late asthmatic response (LAR) as well as delayed asthmatic response (DeAR) is an important clinical characteristic in adult severe asthma. These responses might be based on cell to cell interaction following lymphocyte activation. Therefore, to clarify the pathogenesis of LAR, we studied the lymphocyte functions of adult asthmatics with LAR provoked by inhalation of house dust and Candida antigen. The results revealed that mite antigen-specific lymphocyte blastogenesis, IL-2 and ECF production were significantly higher in asthmatics with LAR provoked by house dust antigen than in normal subjects and asthmatics with IAR by house dust and LAR by Candida, though there was no significant difference in NCF. Candida antigen-specific lymphocyte blastogenesis, IL-2, ECF and NCF production were significantly higher in asthmatics with LAR provoked by Candida antigen than in normal subjects and asthmatics with IAR or LAR provoked by house dust. There was a positive correlation between Candida antigen-specific IL-2 and NCF production in asthmatics with LAR provoked by Candida antigen. These results suggest that antigen-specific lymphocyte activation may play an important role in the pathogenesis of LAR, especially in asthmatics with LAR provoked by Candida antigen, and that LAR and DeAR should be considered inclusively as cell-mediated allergy.

Adolescent↗

PubMed1992

[Studies on the T-cell subset in lung tissue and BALF from patients with interstitial pneumonia].

The cellular components in bronchoalveolar lavage fluids (BALF) have been analyzed to obtain information on cellular kinetics in lung tissues of patients with diffuse pulmonary diseases. While various cells, alveolar macrophages, lymphocytes, and granulocytes appear in BALF, an increase in the percentage of lymphocytes has been noted in a variety of interstitial pneumonia. The T-cell subset of lymphocytes in BALF and biopsied lung tissues was, therefore, examined in patients with hypersensitivity pneumonitis (HP), sarcoidosis (Sar), idiopathic interstitial pneumonia (IIP) and rheumatoid arthritis with interstitial pneumonia (RA+IP) to compare the ratios of CD4/CD8 in BALF and lung tissues. The T-cell subset in BALF was analyzed by flow cytometry and the T-cell subset in lung tissues was detected with fresh frozen and thin-sliced specimens using an avidine-biotin complex (ABC) kit (Vecta Co. Ltd). The mean CD4/CD8 ratio in BALF was 0.36 in HP, 3.1 in Sar, 1.07 in IIP and 2.59 in RA+IP, while the mean CD4/CD8 ratio in lung tissues was 0.52 in HP, 2.59 in Sar, 1.11 in IIP and 2.25 in RA+IP, respectively. The ratios of CD4/CD8 in BALF and lung tissues from patients with these various interstitial pneumonia showed a positive correlation indicating that the changes of cellular components in BALF would reflect the changes in the lung tissues. Furthermore, CD4/CD8 ratios of lymphocytes infiltrating the alveolar portion and granuloma in lung tissues of HP were analyzed separately, because the CD4/CD8 ratios varied considerably from part to part of the lung tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolitis, Extrinsic Allergic↗

PubMed1992

[The cellular kinetics in BAL fluid of hypersensitivity pneumonitis and pulmonary function].

The cellular components of bronchoalveolar lavage (BAL) fluid of patients with hypersensitivity pneumonitis were analyzed in regard to the inhalation period of antigen in the environment before BAL procedure. BAL fluid in early phase of antigen inhalation contained increased percent of neutrophils as well as lymphocytes while low percent of neutrophils and prominent increase of lymphocytes in chronic antigen inhalation. Furthermore, the increased neutrophils in BAL fluid decreased rapidly after admission as cessation of antigen inhalation while the lymphocyte percent decreased gradually. In relation to respiratory function the lymphocyte percent showed statistically significant negative correlation with %TLC, %VC and %DLco. On the other hand the percent of neutrophils showed some relationship with the airway damage and inflammatory changes in early phase of this disease.

Alveolitis, Extrinsic Allergic↗

PubMed1992

[A case report of pulmonary infiltration with eosinophilia syndrome induced by Candida albicans].

A sixty six-year-old female who had been treated for bronchial asthma for about 25 years was admitted to the hospital with complaints of episodes of dyspnea, eosinophilia and infiltrative shadows in the chest X-ray film. An infiltrative shadow appeared to move from the left to the right lung field and finally formed a shadow of atelectasis in the middle field of the right lung. A sputum culture showed only Candida albicans. Allergic and immunologic examination revealed high IgE serum levels with specific IgE against Candida albicans in high titer, and Aspergillus fumigatus in low titer. The precipitating antibody was shown only against Candida antigen. Additionally, the blastogenic response to Candida antigen was high in comparison with other fungal antigens including Aspergillus fumigatus. The clinical features and laboratory findings of this patient were found to satisfy Rosenberg's criteria for allergic bronchopulmonary aspergillosis (ABPA), except for the existence of Candida albicans in place of Aspergillus species as the causative antigen. The pathogenesis of PIE syndrome has been studied and various allergic mechanisms against many antigens reported. In this patient Candida albicans could be playing the crucial role in the formation of PIE syndrome, which might be best described as allergic bronchopulmonary candidiasis (ABPC).

Aged↗

PubMed1992

[The significance of soluble IL-2 receptors in rheumatoid arthritis with interstitial pneumonia].

Interstitial pneumonia is well known as one of the complications of rheumatoid arthritis (RA). While interleukin-2 (IL-2) regulates the immune response through IL-2 receptor (IL-2R), the exact role of the soluble form of IL-2R (sIL-2R), recognized as a part of the alpha chain or IL-2R, is still obscure. So, the immunological significance of sIL-2R in serum and in bronchoalveolar lavage fluid (BALF) of those of RA patients with or without interstitial pneumonia was studied. The sIL-2R was measured with an ELISA kit (T-Cell Science Ltd). The levels of sIL-2R in the sera of RA patients without interstitial pneumonia were significantly higher than those of normal controls. Furthermore, the levels of sIL-2R showed a statistically significant correlation with ESR and Lansbary's index. The levels of sIL-2R of RA patients with interstitial pneumonia were higher than in those without interstitial pneumonia although the evaluation of class and stage of arthritis in those RA patients with or without interstitial pneumonia revealed no significant difference. A high sIL-2R/albumin ratio in BALF of RA patients with interstitial pneumonia was shown in comparison with those of normal control. These data indicate that the estimation of sIL-2R in RA patients could be useful in estimating the disease activity and that high levels of sIL-2R reflect the active immune response in the lungs of RA patients with interstitial pneumonia.

Arthritis, Rheumatoid↗

PubMed1992

[Asthma classification by score calculated from clinical findings and examinations. Comparison between clinical diagnosis and score diagnosis].

Asthma classification by clinical symptoms and signs (clinical diagnosis) was compared with the classification by score calculated from clinical findings and examinations (score diagnosis) in 25 patients with bronchial asthma. 1. Ten subjects classified as Ia (simple bronchoconstriction type) by clinical diagnosis were divided into 6 cases with expectoration of less than 49 ml a day and 4 cases with expectoration of between 50 and 99 ml. The level of serum IgE and number of eosinophils in BALF were significantly higher in the latter cases than in the former cases. The cases whose expectoration was from 50 to 99 ml a day were classified as Ib (bronchoconstriction with hypersecretion type) by score diagnosis. 2. The six subjects who were classified as type Ib by clinical diagnosis were also evaluated as type Ib by score diagnosis. 3. Nine of the 10 subjects classified as type II by clinical diagnosis were evaluated as type II by score diagnosis. One case, whose score was under 12 points, was evaluated as questionable type II by score diagnosis.

Adult↗