Biomedical subjects

Y Kamio

Publications and source records attributed to Y Kamio.

At least 109 records · Page 6Linked to original sources

PubMed1995

Repeated inhalation challenge with exogenous and endogenous histamine released by acetaldehyde inhalation in asthmatic patients.

We previously reported that inhaled acetaldehyde, a metabolite of ethanol and a main factor in alcohol-induced asthma, causes bronchoconstriction indirectly through endogenously released histamine in asthmatic subjects. No study has examined the difference between tachyphylaxis in response to endogenous as opposed to exogenous histamine. Therefore, we examined tachyphylaxis occurring in response to repeated inhalation of histamine or acetaldehyde in nine asthmatic subjects. The mean acetaldehyde concentration causing a 20% decrease in FEV1 increased significantly from 18.4 (geometric standard error of the mean (GSEM = 0.14) to 45.2 (GSEM = 0.14) mg/ml over a period of 1 h (p < 0.002), whereas the mean histamine concentrations causing a 20% decrease in FEV1 were identical. No correlations were observed between the change in bronchial responsiveness to each solution and the change in baseline FEV1. These results suggest that tachyphylaxis in response to histamine is observed only when the latter is released endogenously. We believe that this is the first report suggesting tachyphylaxis caused by endogenous histamine.

Acetaldehyde↗

PubMed1995

Essential binding of LukF of staphylococcal gamma-hemolysin followed by the binding of H gamma II for the hemolysis of human erythrocytes.

Staphylococcal gamma-hemolysin consists of two protein components, LukF and H gamma II. This report clarifies the order of binding of the two components to human erythrocytes for the hemolytic activity of the toxin. The initial binding of LukF to the human erythrocytes is essential for the subsequent binding of H gamma II to the same cells, with the formation of a heat-undissociable protein of about 100 kDa containing LukF and H gamma II.

Bacterial Proteins↗

PubMed1995

Identification of the essential regions for LukS- and H gamma II-specific functions of staphylococcal leukocidin and gamma-hemolysin.

Staphylococcal leukocidin and gamma-hemolysin consist of LukF and LukS for leudocidin and LukF and H gamma II for gamma-hemolysin. To identify the pivotal domain(s) of LukS and H gamma II responsible for their specific cytolytic activities, a series of chimeric genes (lukS/hlg2) were constructed and expressed in Escherichia coli. The results indicate that the C-terminal 24-residue and the N-terminal 57-residue segments of LukS and H gamma II, respectively, are the essential regions for the LukS and H gamma II functions.

Amino Acid Sequence↗

PubMed1995

Substitution of lysine for arginine in the N-terminal 217th amino acid residue of the H gamma II of Staphylococcal gamma-hemolysin lowers the activity of the toxin.

The staphylococcal toxin gamma-hemolysin consists of two protein components, LukF and H gamma II. Staphylococcus aureus P83 was found to have five components, LukF, LukF-PV, LukM, LukS, and H gamma II for leukocidin or gamma-hemolysin. H gamma II of S. aureus P83 was demonstrated to be a naturally-occurring analogous molecule of H gamma II [H gamma II(P83)], in which the 217th arginine residue was replaced by lysine. The H gamma II(P83) showed about 50% of the hemolytic activity of normal H gamma II in the presence of LukF.

Amino Acid Sequence↗

PubMed1995

Molecular cloning and sequence analysis of the gene encoding the collagenase from Cytophaga sp. L43-1 strain.

Cytophaga sp. strain L43-1 secretes a collagenase [Y. Sasagawa et al., Biosci. Biotech. Biochem., 57, 1894-1898 (1993)]. A cog gene encoding the collagenase from this strain was cloned, and the nucleotides were sequenced. The structural gene of cog consisted of 3846 base pairs, which encoded a polypeptide consisting of 1282 amino acid residues with a predicted molecular mass of 130 kDa which was synthesized as a pre-matured enzyme. The deduced N-terminal 14 amino acids sequence, molecular mass of 120 kDa, and pI of 4.96 of the predicted matured enzyme were consistent with those previously found for the collagenase purified from the strain. The cog gene was expressed in Escherichia coli using the lac promoter and ribosomal binding sequence in plasmid vector pUC119 or pKK223-3, but not its own putative promoter and Shine-Dalgarno sequence. The consensus amino acid sequence (His-Glu-Xaa-Xaa-His) of an active site of the metal proteases including the collagenase from Vibrio arginolyticus and a series of human MMPs was found in the Cog protein of the strain.

Amino Acid Sequence↗

PubMed1995

[Tibial nerve somatosensory evoked potentials: studies on latency variability as a function of subject height and age].

Scalp-recorded somatosensory evoked potentials (SEP) to posterior tibial nerve stimulation were studied in healthy volunteers (27 males and 25 females) aged 15-67 years. Age alone was not correlated with SEP latencies, except for P 60 latency, but multiple regression analysis with two independent variables (height and age) showed that not only height but also age is a significant parameter in determining the optimal clinical limits for individual SEP latencies, and may increase the diagnostic sensitivity of absolute SEP latencies. There was no gender difference in the latencies of SEP in multiple correlation analysis involving height and age. A negative correlation tended to be found between height and age in adult subjects, although this is thought to be a characteristic of Japanese, it may show the necessity of renewing regression models at intervals of 5 or 10 years.

Adolescent↗

PubMed1995

Prostanoids and cough response to capsaicin in asthma and chronic bronchitis.

Cyclooxygenase products are released by chronic airway inflammation. Our working hypothesis for the present study was that prostanoids augment airway cough sensitivity. The effects of a cyclooxygenase inhibitor, indomethacin (100 mg.day-1 for 4 days), and a thromboxane synthesis inhibitor, OKY-046 (400 mg.day-1 for 4 days), on cough response to inhaled capsaicin were examined in eight patients with asthma, 10 patients with chronic bronchitis, and 10 normal subjects. Capsaicin cough threshold, the lowest concentration of capsaicin eliciting five or more coughs, was measured as an index of airway cough sensitivity. In asthmatics, the cough thresholds with indomethacin treatment (15.7 (GSEM 1.38) microM) and OKY-046 (10.2 (GSEM 1.20) microM) were significantly greater than the value with placebo (6.05 (GSEM 1.25) microM). In patients with chronic bronchitis, the cough threshold was significantly greater with indomethacin (5.94 (GSEM 1.50) microM) than with placebo (3.41 (GSEM 1.33) microM and OKY-046 2.97 (GSEM 1.43) microM). In normal subjects, the capsaicin cough threshold was not altered by indomethacin or OKY-046 treatment. These results support our hypothesis and suggest that thromboxane A2 may be one of the cyclooxygenase products augmenting airway cough sensitivity in asthma, but not in chronic bronchitis.

Adult↗

PubMed1994

Molecular cloning and sequence analysis of the gene encoding the H2O2-forming NADH oxidase from Streptococcus mutans.

Streptococcus mutans induces both H2O2-forming and H2O-forming NADH oxidases in the presence of O2 [M. Higuchi, J. Gen. Microbiol., 130, 1819-1826 (1984)]. In this paper, a nox-1 gene encoding H2O2-forming NADH oxidase (NOX-1) from Streptococcus mutans was cloned, and the nucleotides sequenced. The structural gene of nox-1 consisted of 1530 base pairs, which encode a polypeptide consisting of 510 amino acids with a predicted molecular mass of 55,196 Da. The deduced N-terminal amino acid sequence was consistent with that previously found for the purified NOX-1 protein. The nox-1 gene was expressed in Escherichia coli using its own promoter. Alignment of the amino acid sequence of NOX-1 with those of NADH oxidases from other microorganisms showed identities of 55.6%, 20.8%, 20.3%, and 7.3% for those of Amphibacillus xylanus Ep01, Streptococcus faecalis 10C1, Thermoanaerobium brockii Rt8.G4, and Thermus thermophilus HB8, respectively.

Amino Acid Sequence↗

PubMed1994

Expression of a pectin lyase gene in Escherichia coli from Pseudomonas marginalis N6301.

We constructed deletion mutant clones of a pectin lyase gene, and measured their pectin lyase activities in Escherichia coli. Pectin lyase activities were detected only in a recA+ strain but not in a recA- strain of E. coli. We also cloned and sequenced recA from Pseudomonas marginalis N6301. The recA from P. marginalis N6301 can complement recA- to form recA+ in the phenotype of E. coli. Highly conserved sequences of recA are observed among E. coli, P. fluorescens, and P. marginalis. From these results, we presume that recA is required for the expression of the pectin lyase gene in P. marginalis N6301.

Amino Acid Sequence↗

PubMed1994

Analysis of promoter region of the pectin lyase gene from Erwinia carotovora Er.

A pectin lyase defective mutant was constructed from Erwinia carotovora Er by transposon Tn5 insertion mutagenesis to analyze the promoter region of the pnl gene, which had been cloned. The promoter of pnl is between -140 and -74 upstream of the structural gene of pnl and appears not to be regulated by Lex A.

Amino Acid Sequence↗

PubMed1994

Inactivation of gamma-hemolysin H gamma II component by addition of monosialoganglioside GM1 to human erythrocyte.

The Staphylococcal toxins leukocidin and gamma-hemolysin consist of two protein components: F and S in leukocidin and H gamma I and H gamma II in gamma-hemolysin. The two toxins share one component (F = H gamma I). We found that the H gamma II component was completely inactivated by the addition of monosialoganglioside GM1 at the molar ratio of 1:1. Disialogangliosides GD1a and GD1b had little effect on the inactivation of H gamma II. The molar ratios of GD1a and GD1b to H gamma II needed for maximum inactivation were 30:1 and 100:1, respectively. Related glycolipids caused little if any inactivation. H gamma II bound to GM1 to form H gamma II-GM1 complexes. Analysis of the intrinsic aromatic amino acid fluorescence in H gamma II and H gamma II-GM1 with 280 nm as the excitation wavelength showed that GM1 in the complex reduced the fluorescence intensity of H gamma II by 12% without changing the wavelength of maximum emission (325 nm). We concluded that GM1 is a receptor of the H gamma II component on human erythrocytes and that H gamma II takes on a different conformation when it binds to GM1.

Amino Acid Sequence↗

PubMed1994

Cough receptor sensitivity and bronchial responsiveness in patients with only chronic nonproductive cough: in view of effect of bronchodilator therapy.

Twenty-two patients with only chronic nonproductive cough lasting for more than 2 months were prospectively examined to determine whether airway cough receptor sensitivity and bronchial responsiveness relate to the efficacy of bronchodilator therapy on the cough. Clenbuterol (10 micrograms, 4 times a day for 1 week) was effective on the cough in 10 patients (group 2) but not in the other 12 patients (group 1). Cough threshold to inhaled capsaicin was significantly less in group 1 than in group 2 at the first visit but not after the therapy when the cough stopped. Bronchial responsiveness to methacholine (PC20-FEV1) was not heightened in group 1, while that in group 2 was hyperreactive. These findings suggest that nonproductive cough is elicited based on two different mechanisms: (1) heightened airway cough receptor sensitivity in bronchodilator-resistant cough and (2) bronchoconstriction in bronchodilator-responsive cough such as cough-variant asthma.

Adult↗

PubMed1993

The C-terminal region of the S component of staphylococcal leukocidin is essential for the biological activity of the toxin.

The Staphylococcal toxin leukocidin consists of two protein components, F and S. From a culture medium of Staphylococcus aureus RIMD 310925, we isolated a truncated form of S (LS2), of which the C-terminal 17-residue segment is missing. Unlike intact S, LS2, showed neither leukocytolytic activity in the presence of F nor affinity for monosialoganglioside GM1 (GM1). When excited at 280 nm, both S and LS2 exhibited intrinsic tryptophan fluorescence with an emission maximum at 318 nm. Upon binding to GM1, the emission maximum of S underwent a blue shift to 310 nm, whereas no change in fluorescence took place on mixing GM1 with LS2. We conclude that the C-terminal region of S is essential for its biological activity as well as for its binding to GM1 and that this binding is accompanied by a conformational change of the S protein.

Amino Acid Sequence↗

PubMed1993

The two Staphylococcal bi-component toxins, leukocidin and gamma-hemolysin, share one component in common.

Staphylococcal bi-component toxins, leukocidin and gamma-hemolysin, consist of two protein components, i.e. F and S for leukocidin and H gamma I and H gamma II for gamma-hemolysin. In this study we purified H gamma I and H gamma II to homogeneity from the culture medium of Staphylococcus aureus RIMD 310925 and compared their properties with those of F and S purified from the same source. The N-terminal 59- and C-terminal 2-residue amino acid sequences, apparent molecular mass, and isoelectric point of purified H gamma I were the same as those of F. In an Ouchterlony double diffusion test a fused line without spur was formed between F and H gamma I using either anti-F or anti-H gamma I antibodies. A synergistic action of F and H gamma II caused hemolysis of human red blood cells, and H gamma I acted synergistically with S to exhibit leukocidin activity. We conclude that the two toxins share one protein component (F = H gamma I) in common and leukocidin- and gamma-hemolysin-specific activities are determined by S and H gamma II, respectively. It is also reported that the N-terminal 58-residue sequence of H gamma II is 72% similar to the corresponding sequence of S.

Amino Acid Sequence↗

PubMed1993

Bronchodilator effects of oxitropium bromide, fenoterol, and their combination in normal subjects.

Oxitropium bromide is a quaternary anticholinergic compound based on the scopolamine molecule instead of atropine. The purpose of this study was to compare the bronchodilator effects of oxitropium, a beta 2-agonist fenoterol, and their combination, on basal bronchomotor tone in normal subjects. Partial flow-volume curve (PEF25), was measured as an index representing bronchomotor tone. The cumulative dose-response curve of oxitropium bromide inhaled from a metered-dose inhaler was determined in eleven normal subjects. Measurement of PEF25 was repeated every 1 h for 8 h after inhalation of oxitropium (200 micrograms), fenoterol (200 micrograms), their combination or placebo in six normal subjects in a randomized, single-blinded, placebo-controlled, cross-over manner. As the percentage increase in PEF25 by 200 micrograms of oxitropium (45 +/- 6%) was equivalent to nearly 80% of that by dose of 1,600 micrograms (58 +/- 8%), the dose of 200 micrograms is thought to be appropriate. The group mean percentage increase in the PEF25-time course curve was significantly greater after treatment with the combination than with placebo (p < 0.001) and fenoterol (p < 0.001) but not with oxitropium bromide, while the increase in PEF25 following the combination was significantly greater than that following oxitropium bromide after 2 and 3 h. These findings indicate that in normal subjects oxitropium has a powerful bronchodilator effect and that the addition of oxitropium to fenoterol caused greater bronchodilation in normal subjects.

Adult↗

PubMed1993

Effect of a leukotriene antagonist, ONO-1078, on bronchial hyperresponsiveness in patients with asthma.

To evaluate the involvement of sulphidopeptide leukotrienes on bronchial hyperresponsiveness in asthma, we examined the effects of a specific orally active leukotriene antagonist (ONO-1078) on bronchial responsiveness to methacholine in stable asthmatic subjects by a double-blinded, randomized, two-phase crossover study. Eleven asthmatic subjects received ONO-1078 (225 mg twice a day) or placebo. After 1 week administration of ONO-1078 or placebo, the subjects underwent methacholine challenge test. Test drug administrations were then discontinued for 1 week, and the subjects were then crossed over to the alternative treatment regimen. After 1 week of the alternate regimen, the subjects underwent a second methacholine challenge. Mean baseline values of forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) and geometric mean value of provocative concentration of methacholine causing a 20% fall in FEV1 (PC20-FEV1) were equal between the first and the second methacholine test. The geometric mean value of PC20-FEV1 after the administration of ONO-1078 was 0.48 (geometric SEM, 1.48) mg ml-1, which was significantly (P < 0.01) greater than the value after the placebo administration (0.30 geometric SEM, 1.41 mg ml-1), but the baseline values of FVC and FEV1 were not altered by ONO-1078. We conclude that sulphidopeptide leukotrienes are significantly involved in the development of bronchial hyperresponsiveness in asthma but the degree of the involvement may be small.

Adult↗

PubMed1993

Identification of two distinct NADH oxidases corresponding to H2O2-forming oxidase and H2O-forming oxidase induced in Streptococcus mutans.

Two distinct NADH oxidases, corresponding to H2O2-forming and H2O-forming enzymes were purified to homogeneity from Streptococcus mutans and their basic properties determined. The H2O2-forming enzyme was a tetramer with a subunit molecular mass of about 56 kDa and required flavin adenine dinucleotide (FAD) for full activity. The enzyme had an isoelectric point of 6.6 and exhibited optimal activity at pH 6.0. The H2O-forming enzyme was a monomer with a molecular mass of 50 kDa and activity independent of exogenously added flavin. The enzyme had an isoelectric point of 4.8 and exhibited optimal activity between pH 7.0 and 7.5. Both enzymes oxidized NADH (Km 0.05 and 0.025 mM for the H2O2- and H2O-forming enzyme, respectively) but not NADPH and contained 1 mol of FAD per monomer. Spectra of the oxidized enzymes exhibited maxima at 271, 383 and 449 nm for the H2O2-forming enzyme and 271, 375 and 447 nm for the H2O-forming enzyme. Antibodies raised against the H2O2-forming enzyme or the H2O-forming enzyme reacted with their corresponding antigen, but did not cross-react. The amino-terminal regions of the two enzymes had completely different amino acid sequences.

Amino Acid Sequence↗

PubMed1993

Effect of inhaled procaterol on cough receptor sensitivity to capsaicin in patients with asthma or chronic bronchitis and in normal subjects.

BACKGROUND: To evaluate the effect of inhaled beta 2 adrenergic agonists on the sensitivity of airway cough receptors, the effect of inhaled procaterol on cough induced by aerosolised capsaicin, a stimulant of C fibres, was studied in patients with asthma or chronic bronchitis and in normal subjects. METHOD: Eleven patients with asthma and 10 with chronic bronchitis and 14 normal subjects participated. Increasing concentrations of capsaicin solution were inhaled for 15 seconds by tidal breathing through the mouth at one minute intervals until five or more coughs were elicited, before and 30 minutes after inhalation of 20 micrograms procaterol or placebo (freon gas alone) through a metered dose inhaler. Cough threshold was defined as the lowest concentration of capsaicin that elicited five or more coughs. To evaluate the bronchodilator effect of procaterol and the bronchoconstrictor effect of inhaled capsaicin, forced expiratory volume in one second (FEV1) was measured before and one minute after a capsaicin provocation test. This test was carried out both before and 30 minutes after treatment with procaterol or placebo. RESULTS: The geometric mean value of cough threshold to capsaicin was significantly increased by procaterol and placebo in both groups of patients but not in the control subjects. The increment in the cough threshold was not significantly different between the treatments with procaterol and placebo in each group. FEV1 was significantly increased by procaterol but not by placebo in all three groups. CONCLUSIONS: Inhaled procaterol has no effect on airway cough receptor sensitivity to capsaicin. The attenuation of the cough sensitivity seen after inhalation of procaterol in patients with asthma and bronchitis may result from tachyphylaxis to capsaicin.

Administration, Inhalation↗