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Biomedical subjects

Y Kamio

Publications and source records attributed to Y Kamio.

At least 91 records · Page 5Linked to original sources
PubMed1997

Identification of the essential amino acid residues in lukS for the hemolytic activity of staphylococcal leukocidin towards rabbit erythrocytes.

Staphylococcus aureus V8 (ATCC 49775) produces Panton-Valentine leukocidin (PVL) and leukocidin (Luk). PVL and Luk consist of LukF-PV and LukS-PV, and LukF and LukS, respectively. LukF and LukS cooperatively and strongly lyse rabbit erythrocytes besides human and rabbit polymorphonuclear leukocytes. LukF and LukS-PV also cooperatively lysed rabbit erythrocytes, but its activity was only 4% of that in combination [LukF-LukS] after 15 min of incubation. To identify the pivotal region responsible for the hemolytic function of LukS towards rabbit erythrocytes, we created a series of chimeric genes (lukS-PV/lukS) and mutant genes of lukS-PV and had them expressed in Escherichia coli. The chimeric and mutant proteins purified from the sonicated extract from the cells of E. coli were assayed for their hemolytic activities towards rabbit erythrocytes in combination with LukF or LukF-PV. The results indicate that a 2-residue segment (D12I13) of lukS is the minimum region essential for the hemolytic function of LukS towards rabbit erythrocytes.

Amino Acid Sequence↗
PubMed1997

Gene of LukF-PV-like component of Panton-Valentine leukocidin in Staphylococcus aureus P83 is linked with lukM.

Staphylococcus aureus P83 (ATCC 31890) produces five components, I to V for synergistic toxins, leukocidin and gamma-hemolysin [Sudo et al., Biosci. Biotech. Biochem., 56, 1786-1789 (1995)]. We report here the identification of component II, which is designated LukF-PV(P83) and its gene (lukF-PV(P83)). The lukF-PV(P83) gene was found to be one base downstream of the stop codon of the lukM gene. The deduced amino acid sequence of LukF-PV(P83) showed 78.4% identity with that of LukF-PV. The lukM and lukF-PV(P83) genes were encoded as one operon like that of Panton-Valentine leukocidin.

Amino Acid Sequence↗
PubMed1997

Molecular biology of the pore-forming cytolysins from Staphylococcus aureus, alpha- and gamma-hemolysins and leukocidin.

Staphylococcus aureus is an important opportunistic pathogen. It produces a variety of extracellular proteins, which may play important roles in infections by this bacterium. Staphylococcal alpha-toxin is a pore-forming 33-kDa polypeptide. In the first part of this article, we will refer to the roles of cell membranes in the pore formation by alpha-toxin as well as the molecular dissection of alpha-toxin for understanding its pore-forming nature. Staphylococcal gamma-hemolysin and leukocidin are bi-component cytolysins, which have different cell specificities towards erythrocytes and leukocytes, respectively. We have found that these bi-component cytolysins share a common component. In the second part of this article, we will refer to the current status of knowledge of molecular cloning of the genes coding for gamma-hemolysin and leukocidin, molecular domains of the toxins which decide the cell specificities, and mode of action of these bi-component toxins.

Amino Acid Sequence↗
PubMed1997

Sequential binding of Staphylococcal gamma-hemolysin to human erythrocytes and complex formation of the hemolysin on the cell surface.

Staphylococcal gamma-hemolysin consists of two protein components, F (or H gamma I) and H gamma II. To elucidate the mode of action of gamma-hemolysin, we studied the binding order of F and H gamma II to human erythrocytes and the cell-bound state of the two components. The binding of F to human erythrocytes preceded the binding of H gamma II to the cells, and thereafter hemolysis occurred. Western immunoblot analysis of the cell-bound gamma-hemolysin indicated that F and H gamma II components form high-molecular-mass (150-250 kDa) complexes on the erythrocytes. The toxin complexes were recovered in a Triton X-100-insoluble fraction of the erythrocytes, which contains cytoskeleton proteins. Neither the formation of the toxin complex(es) nor hemolysis occurred when the erythrocytes were treated with proteinase K. Abortion of the complex formation on the proteinase K-treated erythrocytes may be due to the failure of the binding of H gamma II to the cells, because F bound to the proteinase K-treated erythrocytes to the same extent as to the non-treated erythrocytes.

Amino Acid Sequence↗
PubMed1997

Detection of eosinophils in hypertonic saline-induced sputum in patients with chronic nonproductive cough.

This study was conducted to examine (1) whether an appropriate sputum can be obtained by inducing with inhalation of hypertonic saline in patients with chronic nonproductive cough and (2) whether eosinophils can be detected in the induced sputum. Appropriate samples were obtained by the induction in 25 of 31 patients with bronchial asthma (BA), 12 of 17 patients with cough-variant asthma (CVA), 17 of 20 patients with bronchodilator-resistant cough associated with atopy (atopic cough, AC), and 23 of 25 healthy subjects. Eosinophils were detected in the successfully induced sputum in 100%, 66.6%, and 88.2% of the patients with BA, CVA, and AC, respectively. Detection of eosinophils in induced sputum may be the initial diagnostic procedure for nonproductive cough of allergic nature.

Adolescent↗
PubMed1996

Effect of capsaicin inhalation on methacholine responsiveness in normal subjects.

It has been reported that capsaicin stimulates bronchial C-fibers to release neuropeptides and enhances bronchial responsiveness in animal studies. This study was conducted to examine the effect of inhaled capsaicin on bronchial responsiveness in humans. A provocative concentration of methacholine producing a 20% fall in forced expiratory volume in one second (PC20-FEV1) was measured before and one hour after, one minute inhalation of 15.6 microM capsaicin solution (capsaicin day) or saline (saline day) in seven normal subjects whose PC20-FEV1 values were 40 mg/ml or less. Geometric mean value of PC20-FEV1 measured one hour after saline inhalation following pretreatment methacholine challenge was 89.3 (GSEM, 1.69) mg/ml which was significantly (p = 0.018) greater than that of the pre-treatment methacholine challenge [19.1 (GSEM, 1.37) mg/ml] on a saline day. However, PC20-FEV1 was not different before and one hour after inhalation of capsaicin [18.1 (GSEM, 1.40) and 23.1 (GSEM, 1.80) mg/ml] on a capsaicin day. The PC20-FEV1 value of the post-treatment methacholine test was significantly (p = 0.0277) lower after capsaicin inhalation than after saline inhalation while the value of pre-treatment methacholine provocation was not different between capsaicin and saline days. Change of the post-treatment PC20-FEV1 from the pre-treatment value shown as doubling concentrations was 0.35 +/- 0.60 on a capsaicin day which was significantly lower than that (2.23 +/- 0.47) on a saline day. These results confirm the decreased responses to repeated inhalation of methacholine (methacholine tachyphylaxis) in normal subjects and indicate that capsaicin inhalation reduces the methacholine tachyphylaxis.

Administration, Inhalation↗
PubMed1996

Angiosarcoma of the chest wall.

Angiosarcoma is a rare but highly malignant disease. This report presents a 22-year-old male who has survived a primary angiosarcoma arising from the chest wall. The patient had been complaining of anterior chest pain for 3 years. CT and MRI revealed a tumor protruding into the right thoracic cavity from the anterior chest wall but no further findings. First, the tumor was resected using video-assisted thoracoscopy. The pathological diagnosis established from a frozen section was of a benign mesothelioma, but this was changed to angiosarcoma based on findings from a paraffin-embedded specimen. As a consequence, the third rib and intercostal muscles were resected in a second operation. Three years following surgery there was no evidence of tumor recurrence or metastasis. This case supports a suggestion that not all patients with angiosarcomas experience the same level of malignancy.

Adult↗
PubMed1996

A case of malignant Triton tumor of the lung.

The present paper reports a 28-year-old male with an asymptomaticmalignant Triton tumor of the lung. Chest radiographs revealed a mass in the left hilum. The left lower lobe including the tumor and the mediastinal lymph node was resected. There was no metastasis or tumor recurrence during the one-year period following the surgical procedure. To our knowledge, this is the first case report of a primary pulmonary malignant Triton tumor.

Adult↗
PubMed1996

Female gender as a determinant of cough threshold to inhaled capsaicin.

Chronic, nonproductive cough and cough associated with the use of angiotensin converting enzyme inhibitors, are more frequently observed in females as compared to males. To examine the influence of sex, age, height, weight and pulmonary function on airway cough sensitivity, cough threshold to inhaled capsaicin, an index of the airway cough sensitivity, was measured in 160 nonsmoking, nonatopic healthy subjects. Forty young males (aged 24 +/- 2 yrs) 40 young females (aged 22 +/- 2 yrs) 40 middle-aged males (aged 48 +/- 5 yrs) and 40 middle-aged females (aged 50 +/- 7 yrs) were studied. The cough threshold was defined as the lowest concentration of inhaled capsaicin causing five or more coughs. The cough threshold was 3-5 fold lower in females than in males both in young (p<0.001) and middle-aged (p<0.005) subjects. Cough threshold was weakly but significantly correlated to height, weight, forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) when all subjects were considered together but not when each group was considered separately. Multiple regression analysis revealed that sex difference was the significant predictive factor for the cough threshold in either age group. These results confirm that cough sensitivity is heightened in females and suggest that influence of height and pulmonary function on the cough threshold may have resulted from sex difference.

Adult↗
PubMed1996

Molecular cloning and sequence analysis of the gene encoding the H2O-forming NADH oxidase from Streptococcus mutans.

To discover the molecular properties of two distinct NADH oxidases, corresponding to H2O2-forming oxidase (NOX-1) and H2O-forming oxidase (NOX-2) induced in Streptococcus mutans, for the first step we had cloned and sequenced the nox-1 gene encoding NOX-1. In this paper, a nox-2 gene encoding NOX-2 from S. mutans was cloned, and the nucleotides sequenced. The nox-2 gene comprises 1371 base-pairs, encoding a polypeptide of 457 amino acid residues. The deduced relative molecular mass (M(r) = 49919) agreed with the previous value obtained from the purified NOX-2 protein. The nox-2 gene was expressed in Escherichia coli using its own promoter. Alignment of the NOX-2 protein sequence with that of the NOX-1 showed that the proteins do not significantly resemble each other. Comparisons with the NADH oxidase from Streptococcus faecalis 10C1 yield identities of 41%. The redox-active cysteine in the enzyme from S. faecalis was found to correspond to Cys 44 in the NOX-2.

Amino Acid Sequence↗
PubMed1996

Intrathoracic malignant peripheral nerve-sheath tumour associated with lipoma.

A 76-year-old woman presented with an intrathoracic malignant peripheral nerve-sheath tumour accompanied by mediastinal lipomas. The tumours were resected, but the schwannoma recurred 4 months later. The patient died of pneumonia after a second operation. To our knowledge, this is the first published case of malignant intrathoracic tumour of nerve-sheath origin associated with lipomas.

Aged↗
PubMed1996

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

Somatosensory evoked potentials (SEP) to median nerve stimulation were studied in a group of 61 healthy volunteers (36 men, 25 women) between 15 and 79 years of age. The absolute peak latencies of peripheral N9, Erb, cervical N11 and N13, cortical N20, N32 and N60 were analyzed as a function of height and age. Three interpeak latencies, Erb-N13, Erb-N20 and N13-N20, were equally studied. There was no gender difference in the latencies and interpeak latencies of SEP in multiple correlation analysis involving height and age. Multiple regression analysis showed that except for N60 peak latency, the subject's height and age provided better prediction of other SEP latencies, and Erb-N13 and Erb-N20 interpeak latencies than simple and polynomial [correction of polynominal] linear regression. Multiple regression analysis was found to provide better optimal clinical upper limits for individual SEP latencies and interpeak latencies, and may increase the diagnostic sensitivity. The t-value of the multiple regression coefficient for standardized height and standardized age showed that the effects of age on N32 and N60 peak latencies, and on Erb-N13 and Erb-N20 interpeak latencies were a more important factor than those of height. A negative correlation was found between height and age in our subjects. Although this may be a characteristic of modern Japanese, it suggests the necessity of renewing regression models at intervals of 5 or 10 years.

Adolescent↗
PubMed1995

Existence of a new protein component with the same function as the LukF component of leukocidin or gamma-hemolysin and its gene in Staphylococcus aureus P83.

Staphylococcal toxins, leukocidin and gamma-hemolysin, consist of two protein components, i.e. LukF and LukS for leukocodin and H gamma I and H gamma II for gamma-hemolysin. From a culture fluid of Staphylococcus aureus strain P83, a new protein component of leukocidin or gamma-hemolysin which was designated as LukM was isolated. This component showed the same biological activity as that of LukF component for leukocidin or H gamma I component of gamma-hemolysin in combination with LukS or H gamma II. However, the LukM component cross-reacted with the anti-LukS antibodies but not with the anti-LukF antibodies. On the basis of chemical analysis of the LukM component and the cloning and nucleotide sequencing of the lukM gene of S. aureus P83, we have demonstrated that LukM is an entirely new protein component of leukocidin or gamma-hemolysin. The deduced amino acid sequence of LukM from the lukM gene showed 66.7% and 67% identity to that of LukS and H gamma II, respectively. However, the amino acid sequence of LukM and LukF showed only 29% homology.

Amino Acid Sequence↗
PubMed1995

Effect of a 5-lipoxygenase inhibitor, AL-3264, on propranolol-induced bronchoconstriction in guinea-pigs.

The administration of propranolol can provoke bronchoconstriction in asthmatic patients. We hypothesized that such bronchoconstriction may result from the inflammatory mediators released by an allergic reaction. We investigated the effect of AL-3264, a 5-lipoxygenase inhibitor, on propranolol-induced bronchoconstriction (PIB) after antigen inhalation in passively sensitized and artificially ventilated guinea-pigs. Our goal was to determine whether products of arachidonate 5-lipoxygenase are involved in such PIB. Bronchoconstriction occurred when 10 mg/ml of propranolol was inhaled 20 min after antigen challenge. Pretreatment with AL-3264 given in intravenous doses of 0.01 and 0.1 mg/kg 15 min after the antigen challenge significantly reduced PIB in a dose-dependent manner. Pretreatment with 0.1 mg/kg of AL-3264 10 min before antigen challenge significantly inhibited both the immediate allergic bronchoconstriction and PIB, although the effect was minimal. Results suggest that arachidonate 5-lipoxygenase products (such as leukotriene B4, C4, D4 or E4) are involved in the pathophysiology of PIB but their contribution may be small. Further studies using selective antagonists for each of these leukotrienes are needed to clarify their role.

Acrylamides↗
PubMed1995

Bronchodilator and bronchoprotective effects of cilostazol in humans in vivo.

Cilostazol is a selective orally active phosphodiesterase (PDE) III inhibitor. This study was conducted to evaluate whether inhibition of PDE subtype III can reduce bronchial responsiveness. We examined the effects of cilostazol on bronchial responsiveness to methacholine in eight normal subjects by a single-blinded, crossover study. Each subject received 200 mg of cilostazol or placebo in random order. The subjects underwent methacholine challenge test 3 h after administration of each drug on two occasions separated by 5 d or more. The geometric mean value of provocative concentration of methacholine causing a 20% fall in FEV1 (PC20-FEV1) and the mean value (+/- SEM) of maximum expiratory flow on partial flow-volume curve at isovolume of 40% FVC above residual volume (PEF40) after administration of cilostazol were 25.3 (geometric standard error of the mean [GSEM], 1.35) mg/ml and 3.78 +/- 0.31 L/s, which were significantly (p < 0.02 and p < 0.05) greater than those after the placebo administration (6.81 [GSEM, 1.42] mg/ml and 2.71 +/- 0.39 L/s). All subjects complained of mild to severe headache when cilostazol was given. These findings suggest that PDE III inhibitors such as cilostazol have bronchodilator and bronchoprotective effects in humans. Further studies regarding smaller oral dosing of or aerosol administration of cilostazol or the other PDE III inhibitors are needed to determine clinical usefulness.

3',5'-Cyclic-AMP Phosphodiesterases↗