Biomedical subjects

Y Kamio

Publications and source records attributed to Y Kamio.

At least 73 records · Page 4Linked to original sources

PubMed1998

Airway cough sensitivity to inhaled capsaicin and bronchial responsiveness to methacholine in asthmatic and bronchitic subjects.

The objective of this study was to evaluate the effect of chronic airway inflammation on airway cough sensitivity and non-specific bronchial responsiveness, and the relationship between them. The capsaicin cough threshold, defined as the lowest concentration of capsaicin causing five or more coughs, and non-specific bronchial responsiveness, defined as the methacholine concentration causing a 20% fall in forced expiratory volume in 1 s (FEV1) (PC20-FEV1), were measured in 18 asthmatic, 13 bronchitic (sinobronchial syndrome) and 28 healthy non-atopic subjects. All subjects were non-smoking men. The geometric mean values (mumol) of the cough threshold were 18.9 (GSEM 1.29), 8.69 (GSEM 1.29) and 27.6 (GSEM 1.31) in asthmatic, bronchitic and normal subjects, respectively. The value in bronchitic subjects was significantly lower (P << 0.02) than that in normal subjects. The geometric mean value of PC20-FEV1 in asthmatic subjects (0.48 mg/ml (GSEM 1.38)) was significantly lower than that in bronchitic subjects (18.5 mg/ml (GSEM 1.75)) (P << 0.001). There was no correlation between cough threshold and PC20-FEV1 values (correlation coefficient (r) = 0.155). These results indicate that cough sensitivity is potentiated by chronic airway inflammation in bronchitis but not in asthma, and suggest that cough sensitivity and bronchial responsiveness may be independently potentiated by different mechanisms resulting from chronic airway inflammation.

Administration, Inhalation↗

PubMed1998

Atopy in cough sensitivity to capsaicin and bronchial responsiveness in young females.

We have shown previously that female sex is a determinant of cough sensitivity to inhaled capsaicin, but the relationship between atopy and the cough sensitivity has not been examined. The capsaicin cough threshold, defined as the lowest concentration of capsaicin causing five or more coughs, nonspecific bronchial responsiveness, defined as the provocative concentration of methacholine causing a 20% fall in the forced expiratory volume in one second (PC20), total immunoglobulin E (IgE) and specific IgEs to eight common aeroallergens (house dust 1, 2 and 6, Dermatophagoides pteronyssinus and D. farinae, Japanese cedar, ragweed and orchard grass) in the serum were measured in 71 nonsmoking, healthy young women aged 20.6+/-0.1 yrs (mean+/-EM). A structured interviewer-led questionnaire on allergic diseases revealed that one and six subjects had mild current and past asthma, respectively. These seven subjects were excluded from the data analysis. PC20 was significantly lower in 42 subjects showing a positive specific IgE than in 22 subjects showing a negative specific IgE to any of the eight allergens (p<0.05), while the capsaicin cough threshold was not significantly different between the subgroups. PC20 was significantly lower in subjects with positive specific IgE to Dermatophagoides and house dust, but not to the three kinds of pollen examined. It was confirmed that atopy indicated by specific immunoglobulin E to mite-related antigens, but not to pollen antigens, is associated with nonspecific bronchial responsiveness, and it is suggested that atopy is not a determinant of airway cough sensitivity in healthy, nonasthmatic subjects.

Adult↗

PubMed1998

RpoS-dependent expression of the second lysine decarboxylase gene in Escherichia coli.

The second lysine decarboxylase gene (ldc) is at 4.7 min on the Escherichia coli chromosome [Kikuchi et al., J. Baceriol. 179, 4486-4492 (1997)]. This report showes that the expression of ldc as well as cadA was induced at stationary phase in the wild type of E. coli. The ldc was not expressed in a rpoS deletion mutant of E. coli at any growing stage. In contrast, cadA was expressed in the rpoS mutant. Thus, we conclude that the expression of ldc but not cadA at stationary phase is regulated by a RpoS-dependent mechanism (s) in E. coli.

Adenosine Triphosphatases↗

PubMed1998

An N-terminal region of LukF of staphylococcal leukocidin/gamma-hemolysin crucial for the biological activity of the toxin.

The two staphylococcal bi-component toxins, leukocidin and gamma-hemolysin share LukF [Kamio et al, FEBS Lett., 321, 15-18 (1993)]. This report identifies the pivotal amino acid residues in the N-terminal region of LukF for the leukocytolytic and hemolytic activities in the presence of LukS and HIg2, respectively, measuring the toxin activity of a series of LukF mutants with truncated N-terminals. The data obtained showed that the LukF mutant TF21, lacking 20 amino acid residues at the N-terminus of LukF, failed to have any hemolytic activity and had less 10% leukocytolytic activity than that of the intact LukF, while 16-residue truncations retained both toxin activities without loss. The LukF mutants lacking 18- through 19-residue segments from the N-terminus showed low toxin activity on both target cells. All mutants having no toxin activity were also not capable of binding to the human erythrocytes. It can thus be concluded that the 3-residue segment, L18Y19K20 of LukF is crucial for the biological activity of the toxin.

Amino Acid Sequence↗

PubMed1998

Molecular properties and activity of a carboxyl-terminal truncated form of xylanase 3 from Aeromonas caviae W-61.

Aeromonas caviae W-61 produces five species of xylanases, xylanases 1, 2, 3, 4, and 5 [Nguyen, V.D. et al., Biosci. Biotechnol. Biochem., 56, 1708-1712 (1993) and Appl. Environ. Microbiol., 57, 445-449 (1991)]. While preserving a purified xylanase 3 preparation from A. caviae in solution at 4 degrees C, the xylanase 3 was found to be proteolyzed to give a truncated form with a smaller molecular mass than that of the intact one. It appears likely that the truncated form of xylanase 3 was produced in this particular purification experiment by the action of a contaminating protease. We isolated the truncated form of xylanase 3 (Xyn3tr), of which the C-terminal 102-residue segment is missing. By the chemical analysis of the N- and C-terminal amino acid residues of Xyn3tr and the DNA sequencing analysis of the xylanase 3 gene (xyn3), the N-terminal 398th proline residue of xylanase 3 was found to be the C-terminus of Xyn3tr. Xyn3tr had the activity to form xylotriose (X3), xylotetraose (X4), xylopentaose (X5), and xylohexaose (X6) as main final products from oat spelt xylan. In contrast, intact xylanase 3 released X6 and higher xylo-oligosaccharides as main products. Xylanase 3 hydrolysed X4 through X6. However, Xyn3tr had no activity towards X4 and X5. The recombinant Xyn3tr and recombinant xylanase 3 (XYN3) were purified homogeneously from the periplasmic space of E. coli harboring the plasmids pXYN3 and pXYN3tr, which include xyn3 and xyn3tr genes, respectively, and their enzymatic activities were measured. The cleavage patterns of oat spelt and xylo-oligosaccharides by XYN3tr were identical with that by intact Xyn3tr. Thus, we conclude that the C-terminal region comprising a 102-residue segment in xylanase 3 is involved in governing the molecular size of xylo-oligosaccharides cleaved from beta-1,4-xylan by the enzyme and in the hydrolytic activity towards X4 and X5.

Aeromonas↗

PubMed1998

Further study on the two pivotal parts of Hlg2 for the full hemolytic activity of staphylococcal gamma-hemolysin.

Staphylococcal gamma-hemolysin consists of LukF of 34 kDa and Hlg2 (or H gamma II) of 32 kDa, which cooperatively lyse human and rabbit erythrocytes. Our previous data showed that the 5-residue segment K23R24L25A26I27 of Hlg2 is pivotal for the hemolytic activity [Nariya, H. and Kamio, Y., Biosci. Biotechnol. Biochem., 59, 1603-1604 (1997)]. Here, we identify an additional amino acid residue in Hlg2 necessary for the full gamma-hemolysin activity by measuring the toxin activity of Hlg2 mutants in the presence of LukF. The data obtained showed that Arg217 of Hlg2 is an additional pivotal amino acid residue besides the KRLAI segment for the full Hlg2-specific function in gamma-hemolysin. We also report evidence that the Hlg2 mutants showing a low or null hemolytic activity in the presence of LukF towards human erythrocytes had low or no binding activity to the cells, resulting in failure of formation of the ring-shaped pore-forming complex on the erythrocytes.

Animals↗

PubMed1998

Phosphorylation of LukS by protein kinase A is crucial for the LukS-specific function of the staphylococcal leukocidin on human polymorphonuclear leukocytes.

Staphylococcal leukocidin (Luk) consists of two protein components, LukF and LukS, which cooperatively lyse human and rabbit polymorphonuclear leukocytes. Here, we demonstrate that the phosphorylation of LukS by protein kinase A is crucial for the LukS-specific leukocytolytic function of Luk on HPMNLs by using N-[2(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H-89), which is a potent and selective inhibitor of protein kinase A. At 0.5 microM H-89 completely prevented the Luk-induced cell lysis accompanied by blocking of the incorporation of exogenous 32P-H3PO4 into LukS on HPMNLs. However, with LukS and LukF together, 0.5 microM H-89 did not inhibit the cell swelling which takes place before the cell lysis. HPMNLs also became swollen upon treating with both LukF and LukS mutants which could not be phosphorylated.

Bacterial Proteins↗

PubMed1998

Molecular cloning and sequencing of two phospho-beta-galactosidase I and II genes of Lactobacillus gasseri JCM1031 isolated from human intestine.

Lactobacillus (Lb.) gasseri JCM1031, which is classified into the B1 subgroup of the Lb. acidophilus group of lactic acid bacteria, characteristically produces two different phospho-beta-galactosidases (P-beta-gal) I and II in the same cytosol as reported in our previous papers [Biosci. Biotech. Biochem., 60, 139-141, 708-710 (1996)]. To clarify the functional and genetic properties of the two enzymes, the structural genes of P-beta-gal I and II were cloned and sequenced. The structural gene of P-beta-gal I had 1,446 bp, encoding a polypeptide of 482 amino acid residues. The structural gene of P-beta-gal II had 1,473 bp, encoding a polypeptide of 491 amino acid residues. The deduced relative molecular masses of 55,188 and 56,243 agreed well with the previous value obtained from the purified P-beta-gal I and II protein, respectively. Multiple alignment of the protein sequence of P-beta-gal I and II with those of P-beta-gals from 5 microorganisms had 30-35% identity on the amino acid level, but those with phospho-beta-glucosidases from 5 microorganisms had the relatively high identity of about 50%. Considering that this strain grows on lactose medium and shows no beta-galactosidase activity, and that purified P-beta-gal I and II can obviously hydrolyze o-nitrophenyl-beta-D-galactopyranoside 6-phosphate (substrate), and also the conservation of a cysteine residue in the molecule, the P-beta-gal I and II were each confirmed as a novel P-beta-gal enzyme.

Amino Acid Sequence↗

PubMed1998

[Therapeutic thoracoscopy for empyema thoracis].

In empyema thoracis, it is important to reduce the duration of treatment and to expand the collapsed lung as fully as possible while managing intrathoracic infection. We used thoracoscopy to treat 10 cases of empyema that were not completely cured by antibiotics or thoracic drainage. The 8 men and 2 women were 43-73 years of age. Thoracoscopy was done under general anesthesia except for 2 pneumonia patients. After inserting two trocars into the thoracic cavity, we removed pus, the purulent coat, and fibrinous membrane. Into one unilocular cavity, two intrathoracic tubes were inserted via trocarholes. Postoperative irrigation of the thoracic cavity was conducted daily through the two tubes. We subclassified the fibropurulent stage into three phases, namely, the purulent, fibrous, and purulent-capsular. One case required redrainage, but no cases were accompanied by severe complications or postoperative death. Patients were discharged on post-operative day 33, on average. We found no recurrence or cases of recollapsed lung during the study, from 8 months to 4 years and 11 months postoperatively.

Acute Disease↗

PubMed1997

Identification of the minimum segment in which the threonine246 residue is a potential phosphorylated site by protein kinase A for the LukS-specific function of staphylococcal leukocidin.

Staphylococcal leukocidin and gamma-hemolysin consist of LukF and LukS for leukocidin and LukF and Hlg2 for gamma-hemolysin. In this report, we identify the minimum segment responsible for the LukS-specific function of leukocidin. After chemical analysis and homology study of the amino acid sequence of the C-terminal region between LukS and Hlg2, we found a unique 5-residue sequence I242K243R244S245T246 in LukS in which the 4-residue KRST is identical with that of the phosphorylated segment of a protein phosphorylated by protein kinase A. To elucidate whether the 5-residue segment is essential for the LukS function, we created plasmids containing a series of mutant genes corresponding to the 5-residue sequence and expressed them in Escherichia coli. The mutant proteins were purified and assayed for their leukocytolytic activity with LukF. The mutant MLS-TS, in which the T246 in the 5-residue sequence was replaced by S, showed leukocidin activity 10 times higher than that of the intact LukS. However, neither mutant MLS-TY nor MLS-TA, in which T246 was replaced by Y or A, respectively, showed leukocidin activity. The 5-residue segment was found to be deleted in Hlg2. The mutant of Hlg2, in which the 5-residue segment was inserted at the position that the segment is deleted, showed leukocidin activity. The boiled LukS, MLS-TS, and MHS-Z were strongly phosphorylated with [gamma-32P]ATP in the presence of protein kinase A in a cell-free system. Thus, we conclude that the 5-residue segment 1242K243R244S245T246 is the pivotal segment of LukS responsible for the LukS function of staphylococcal leukocidin.

Adenosine Triphosphate↗

PubMed1997

Assembly of Staphylococcus aureus gamma-hemolysin into a pore-forming ring-shaped complex on the surface of human erythrocytes.

Staphylococcal gamma-hemolysin consists of Hlg1 (or Luk F) of 34 kDa and Hlg2 of 32 kDa, which cooperatively lyse human erythrocytes. Since gamma-hemolysin caused swelling of human erythrocytes prior to lysis, we studied pore-forming nature of the toxin by use of polyethylene glycols as osmotic protectants and determined the functional diameter of the pore. To elucidate the molecular architecture of the membrane pore formed by gamma-hemolysin, we solubilized the pore complex with 2% sodium dodecyl sulfate, separated it from erythrocyte membrane proteins by sucrose gradient ultracentrifugation, and observed the isolated complex under an electron microscope. Our data showed that Hlg1 and Hlg2 of gamma-hemolysin assemble into a ring-shaped 195 kDa complex in a molar ratio of 1 : 1, which may form a membrane pore with a functional diameter of 2.1-2.4 nm.

Bacterial Proteins↗

PubMed1997

Inhibitory effect of indomethacin on tachyphylaxis in response to acetaldehyde-induced bronchoconstriction in patients with asthma.

BACKGROUND: Acetaldehyde, a main factor in alcohol-induced asthma, causes bronchoconstriction indirectly through histamine release; and tachyphylaxis in response to repeated inhalation of acetaldehyde is observed in patients with asthma. OBJECTIVE: The study was designed to clarify the mechanism of tachyphylaxis in response to acetaldehyde-induced bronchoconstriction. METHODS: We investigated the bronchial response to inhaled acetaldehyde in 10 patients with asthma who were treated with indomethacin in a double-blind, randomized, placebo-controlled, crossover fashion. RESULTS: The mean acetaldehyde concentration causing a 20% fall in FEV1 with placebo increased significantly from 13.0 mg/ml (geometric SEM = 0.115) to 31.1 mg/ml (geometric SEM = 0.069) over a period of 1 hour (p < 0.01), whereas there was a slight but not significant tachyphylaxis during indomethacin treatment. The tachyphylactic effect, expressed as logarithmic value of the second PC20 minus logarithmic value of the first PC20, was significantly (p < 0.05) reduced from 0.380 (0.066) with placebo treatment to 0.148 (0.094) with indomethacin treatment. CONCLUSION: These results suggest an important role of cyclooxygenase pathway products in decreased response to repeated inhalation of acetaldehyde in patients with asthma.

Acetaldehyde↗

PubMed1997

Mediastinal tuberculous lymphadenitis diagnosed and treated by thoracoscopy.

Mediastinal tuberculous lymphadenitis is a relatively rare disorder and it is sometimes hard to identify the acid-fast bacilli involved or its specific pathological findings. We employed thoracoscopy to obtain diagnostic material from a 25-year-old woman with a newly-appearing mediastinal mass despite antituberculous therapy for cervical tuberculous lymphadenitis. Thoracoscopy also proved effective in the curative surgical procedure, i.e. resection of the abscess wall as far as possible, debridement of the remaining wall, irrigation, and instillation of streptomycin into the abscess and thoracic cavity. Postoperatively the patient has followed a favorable course for one year.

Abscess↗

PubMed1997

Bactericidal activity of a fermented hot-water extract from Stevia rebaudiana Bertoni towards enterohemorrhagic Escherichia coli O157:H7 and other food-borne pathogenic bacteria.

A fermented aqueous extract from Stevia rebaudiana Bertoni showed strong bactericidal activity towards a wide range of food-borne pathogenic bacteria including enterohemorrhagic Escherichia coli O157:H7. The colony-forming ability of the food-borne pathogenic bacteria tested so far was reduced to < 10(-7) when exposed to > or = 40% (v/v) solutions of the fermented extract at 37 C for 2 hr. Secretion of verocytotoxin 1 and 2 by enterohemorrhagic E. coli was also diminished by fermented extract at a concentration of > or = 10% (v/v). In contrast, the fermented extract did not significantly kill Bifidobacteria or Lactobacilli. The active principle(s) of the fermented Stevia extract were bactericidal under acidic conditions.

Bacterial Toxins↗

PubMed1997

Characterization of a second lysine decarboxylase isolated from Escherichia coli.

We report here on the existence of a new gene for lysine decarboxylase in Escherichia coli K-12. The hybridization experiments with a cadA probe at low stringency showed that the homologous region of cadA was located in lambda Kohara phage clone 6F5 at 4.7 min on the E. coli chromosome. We cloned the 5.0-kb HindIII fragment of this phage clone and sequenced the homologous region of cadA. This region contained a 2,139-nucleotide open reading frame encoding a 713-amino-acid protein with a calculated molecular weight of 80,589. Overexpression of the protein and determination of its N-terminal amino acid sequence defined the translational start site of this gene. The deduced amino acid sequence showed 69.4% identity to that of lysine decarboxylase encoded by cadA at 93.7 min on the E. coli chromosome. In addition, the level of lysine decarboxylase activity increased in strains carrying multiple copies of the gene. Therefore, the gene encoding this lysine decarboxylase was designated Idc. Analysis of the lysine decarboxylase activity of strains containing cadA, ldc, or cadA ldc mutations indicated that ldc was weakly expressed under various conditions but is a functional gene in E. coli.

Amino Acid Sequence↗

PubMed1997

Effect of a phosphodiesterase 3 inhibitor, cilostazol, on bronchial hyperresponsiveness in elderly patients with asthma.

BACKGROUND: Over the last few years, evidence has accumulated that cyclic nucleotide phosphodiesterase (PDE) 3 and/or PDE4 inhibitors may be useful for the treatment of asthma. The present study was designed to examine the effect of a selective orally active PDE3 inhibitor, cilostazol, on bronchial hyperresponsiveness (BHR) of asthma. METHODS: The effect of a single oral dose of cilostazol on BHR was studied in 10 elderly patients with clinically stable asthma, with a mean age of 59.5+/-4.8 years, in a double-blind, crossover, placebo-controlled study. Each subject received 100 mg of cilostazol, 200 mg of theophylline as a positive control or a placebo in a random order. The subjects underwent a methacholine challenge test 3 h after each drug administration on three occasions separated by 2 weeks. RESULTS: The geometric mean value of the provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 s (PC20-FEV1) with cilostazol was 0.48 mg/ml [geometric standard error of the mean (GSEM), 1.40] which was significantly (p<0.01) greater than that with the placebo [0.25 mg/ml (GSEM, 1.36)]. The value with theophylline [0.32 mg/ml (GSEM, 1.54)] did not differ significantly from that with cilostazol or the placebo. Baseline forced vital capacity (FVC) and FEV1 values significantly (p<0.05 and p<0.001, respectively) increased with cilostazol from 2.73+/-0.25 and 1.52+/-0.17 to 2.86+/-0.23 and 1.65+/-0.17 liters, respectively. Theophylline did not significantly increase the FVC or FEV1 value. CONCLUSION: It is suggested that the PDE3 inhibitor, cilostazol, has bronchodilator and bronchoprotective effects in elderly asthmatics.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1997

Identification of the minimum segment essential for the H gamma II-specific function of staphylococcal gamma-hemolysin.

Staphylococcal gamma-hemolysin consists of H gamma I (or LukF) of 34 kDa and H gamma II of 32 kDa, which cooperatively lyse human erythrocytes. Our previous data showed that the N-terminal 57-residue segment of H gamma II is the essential region for the H gamma II function [H. Nariya and Y. Kamio, Biosci. Biotech. Biochem., 59, 1603-1604 (1995)]. To identify the minimum amino acid residues in the 57-residue segment responsible for the specific hemolytic activity, a series of mutant genes were constructed and expressed in Escherichia coli. The mutant proteins were purified and assayed for their hemolytic activity. The results indicate that the 5-residue segment (K23R24L25A26I27) of H gamma II is the minimum region essential for the H gamma II function.

Amino Acid Sequence↗

PubMed1997

Panton-valentine leukocidin genes in a phage-like particle isolated from mitomycin C-treated Staphylococcus aureus V8 (ATCC 49775).

The staphylococcal Panton-Valentine leukocidin (PVL) genes [lukS-PV-lukF-PV] existed in a hexagonal phage-like particle (phi PVL) isolated from mitomycin C-induced Staphylococcus aureus V8 (ATCC 49775). The genome packed in phi PVL was a linear double-stranded 40-kb DNA with single-stranded cohesive ends (cos). The [lukS-PV-lukS-PV], attP, and int (integrase gene) of phi PVL were all located very close to one another within a 4.0 kb-segment on the genome in the order given, and the segment is located at the center from the left and the right cos sites. In addition, the [lukS-PV-lukF-PV]-attP-int region contains 5 direct repeat sequences that show high similarity with the recombinase-binding sites of bacteriophages of S. aureus.

Amino Acid Sequence↗