Biomedical subjects

Y Kamio

Publications and source records attributed to Y Kamio.

At least 55 records · Page 3Linked to original sources

PubMed1999

Vitronectin and its fragments purified as serum inhibitors of Staphylococcus aureus gamma-hemolysin and leukocidin, and their specific binding to the hlg2 and the LukS components of the toxins.

Staphylococcal gamma-hemolysin and leukocidin are bi-component cytolysins, consisting of LukF (or Hlg1)/Hlg2 and LukF/LukS, respectively. Here, we purified serum inhibitors of gamma-hemolysin and leukocidin from human plasma. Protein sequencing showed that the purified inhibitors of 62, 57, 50 and 38 kDa were the vitronectin fragments with truncation(s) of the C-terminal or both N- and C-terminal regions. The purified vitronectin fragments specifically bound to the Hlg2 component of gamma-hemolysin and the LukS component of leukocidin to form high-molecular-weight complexes with them, leading to inhibition of the toxin-induced lysis of human erythrocytes and human polymorphonuclear leukocytes, respectively. Intact vitronectin also showed inhibitory activity to the toxins. The ability of gamma-hemolysin and leukocidin to bind vitronectin and its fragments is a novel function of the pore-forming cytolysins.

Amino Acid Sequence↗

PubMed1999

The influence of psychotic states on the autonomic nervous system in schizophrenia.

Abnormal autonomic activity in patients with schizophrenia has been reported, but how psychotic states influence the autonomic nervous system (ANS) has remained unclear due to methodological limitations. The influence of psychotic states on ANS activity in patients with schizophrenia was investigated using a recently developed method of analysis based on heart rate variability which assesses cardiac sympathetic and parasympathetic function separately. Cardiac autonomic function (CAF), together with psychotic states, was assessed at the beginning and the end of an 8-week study period in 53 patients with chronic schizophrenia. The CAF in age- and sex-matched control subjects was also examined. There were no significant differences between the patients and the control subjects in the mean R-R interval (RRI) or in the indices of the sympathetic and the parasympathetic function. In the patients who changed in psychotic states, the parasympathetic index was significantly decreased without significant changes in the sympathetic index when their psychotic states were more pronounced, suggesting psychotic states suppressed the parasympathetic function without affecting the sympathetic function. In these patients, the mean RRI was smaller when their psychotic states were more pronounced. Our results demonstrate that psychotic states affect the ANS, suggesting a relationship between cerebral cognitive and peripheral ANS activities, and that this is presumably mediated through the parasympathetic nervous system. These findings are discussed in comparison with previous reports on the CAF in schizophrenia.

Adult↗

PubMed1999

Increased airway responsiveness to acetaldehyde in asthmatic subjects with alcohol-induced bronchoconstriction.

Bronchial responsiveness to acetaldehyde, a main factor in alcohol-induced bronchoconstriction, and methacholine were compared between 10 subjects with alcohol-induced bronchoconstriction and 16 asthmatic subjects without alcohol sensitivity. In the alcohol-sensitive group, the geometric mean (geometric SEM (GSEM)) of the provocative concentration of methacholine (PC20,meth) and acetaldehyde (PC20,acet) causing a 20% fall in forced expiratory volume in one second were 0.947 mg x mL(-1) (GSEM 0.139) and 21.0 mg x mL(-1) (GSEM 0.112), respectively, which were not significantly different from those in the nonalcohol-sensitive group, which were 0.634 mg x mL(-1) (GSEM 0.115) and 31.7 mg x mL(-1) (GSEM 0.077), respectively. The ratio of airway responsiveness to acetaldehyde relative to methacholine (log PC20,acet/PC20,meth) was 1.345+/-0.093 (mean+/-SEM) in the alcohol-sensitive group, which was significantly different from the value of 1.699+/-0.059 in the nonalcohol-sensitive group (p=0.0025). A significant correlation was observed between PC20,meth and PC20,acet in both the alcohol-sensitive group (r=-0.742, p=0.0115) and nonsensitive group (r=0.882, p<0.0001). In conclusion, the airways of asthmatic subjects with alcohol-induced bronchoconstriction have a selective hyperresponsiveness to acetaldehyde.

Acetaldehyde↗

PubMed1999

Crystal structure of staphylococcal LukF delineates conformational changes accompanying formation of a transmembrane channel.

Staphylococcal LukF, LukS, HgammaII, and alpha-hemolysin are self-assembling, channel-forming proteins related in sequence and function. In the alpha-hemolysin heptamer, the channel-forming beta-strands and the amino latch make long excursions from the protomer core. Here we report the crystal structure of the water soluble form of LukF. In the LukF structure the channel-forming region folds into an amphipathic, three-strand beta-sheet and the amino latch forms a beta-strand extending a central beta-sheet. The LukF structure illustrates how a channel-forming toxin masks protein-protein and protein-membrane interfaces prior to cell binding and assembly, and together with the alpha-hemolysin heptamer structure, they define the end points on the pathway of toxin assembly.

Amino Acid Sequence↗

PubMed1999

Duration of tachyphylaxis in response to methacholine in healthy non-asthmatic subjects.

It is well recognized that bronchial responsiveness to methacholine is reduced after methacholine-induced bronchoconstriction in non-asthmatic subjects, but not in asthmatic subjects. However, it is unknown how long the methacholine tachyphylaxis lasts. The present study was conducted to elucidate duration of the methacholine tachyphylaxis in healthy non-asthmatic subjects. Measurements of methacholine responsiveness were repeated six times at intervals of 1 h and 1, 2, 3 and 7 days in eight healthy non-asthmatic young female subjects in whom methacholine concentrations causing a 20% fall in forced expiratory volume in 1 sec (FEV1; PC20-Meth) were 40 mg/mL or less. Geometric mean value (GSEM) of PC20-Meth was 10.6 (1.44) mg/mL at the first challenge, 63.4 (1.85) at the 1-h interval, 50.2 (1.67) at the 1-day interval, 49.7 (1.68) at the 2-day interval, 17.3 (1.51) at the 3-day interval and 13.1 (1.44) mg/mL at the 7-day interval. The values at intervals of 1 h to 3 days were significantly greater than the initial value. These results indicate that measurements of methacholine responsiveness should be separated by at least 7 days to avoid the tachyphylaxis when the tests are repeated in non-asthmatic subjects.

Adult↗

PubMed1999

Functions of two types of NADH oxidases in energy metabolism and oxidative stress of Streptococcus mutans.

We have previously identified two distinct NADH oxidases corresponding to H(2)O(2)-forming oxidase (Nox-1) and H(2)O-forming oxidase (Nox-2) induced in Streptococcus mutans. Sequence analyses indicated a strong similarity between Nox-1 and AhpF, the flavoprotein component of Salmonella typhimurium alkyl hydroperoxide reductase; an open reading frame upstream of nox-1 also showed homology to AhpC, the direct peroxide-reducing component of S. typhimurium alkyl hydroperoxide reductase. To determine their physiological functions in S. mutans, we constructed knockout mutants of Nox-1, Nox-2, and/or the AhpC homologue; we verified that Nox-2 plays an important role in energy metabolism through the regeneration of NAD(+) but Nox-1 contributes negligibly. The Nox-2 mutant exhibited greatly reduced aerobic growth on mannitol, whereas there was no significant effect of aerobiosis on the growth on mannitol of the other strains or growth on glucose of any of the strains. Although the Nox-2 mutants grew well on glucose aerobically, the end products of glucose fermentation by the Nox-2 mutant were substantially shifted to higher ratios of lactic acid to acetic acid compared with wild-type cells. The resistance to cumene hydroperoxide of Escherichia coli TA4315 (ahpCF-defective mutant) transformed with pAN119 containing both nox-1 and ahpC genes was not only restored but enhanced relative to that of E. coli K-12 (parent strain), indicating a clear function for Nox-1 as part of an alkyl hydroperoxide reductase system in vivo in combination with AhpC. Surprisingly, the Nox-1 and/or AhpC deficiency had no effect on the sensitivity of S. mutans to cumene hydroperoxide and H(2)O(2), implying that the existence of some other antioxidant system(s) independent of Nox-1 in S. mutans compensates for the deficiency.

Adaptation, Biological↗

PubMed1999

Bronchodilator effect of inhaled olprinone, a phosphodiesterase 3 inhibitor, in asthmatic patients.

The effect of topical administration of phosphodiesterase (PDE) 3 inhibitors on the airway is not clear. In order to examine the usefulness of inhaled PDE3 inhibitors in the treatment of asthma, we investigated the bronchodilator effect of inhaled olprinone, a newly developed PDE3 inhibitor, in nine asthmatic patients. On three separate study days, olprinone, salbutamol, or vehicle was administered in a double-blind and randomized fashion, and pulmonary functions were assessed over 60 min. Significant increases in FEV(1) were observed until 45 min after inhalation of olprinone without adverse cardiovascular effects. Mean maximal increases in FEV(1) were 16.0 +/- 4.0 and 20.5 +/- 4.2% with olprinone and salbutamol, respectively. The bronchodilator effect of olprinone was greater than that of salbutamol in four of the nine patients. These results suggest that the inhaled PDE3 inhibitor has a bronchodilator effect in asthmatic patients.

Administration, Inhalation↗

PubMed1999

Effect of leukotriene and thromboxane antagonist on propranolol-induced bronchoconstriction.

beta-adrenoreceptor blockers such as propranolol provoke bronchoconstriction only in asthmatic patients. Although cysteinyl leukotrienes (cLTs) and thromboxane A2 (TXA2) have been proposed to be involved in the pathophysiology of asthma, the role of these lipid mediators in propranolol-induced bronchoconstriction (PIB) has not been evaluated in asthmatics. This study was conducted to elucidate it. Nine patients with stable asthma, in whom a 20% or more decrease in FEV(1) occurred by inhalation of 20 mg/ml or less propranolol, participated in this study. A cLT antagonist, pranlukast (225 mg twice a day), a TXA2 antagonist, seratrodast (80 mg once a day), and placebo were orally given for 2 wk in a randomized and double-blinded manner. The provocative concentration of propranolol causing a 20% fall in FEV(1) (PC(20)) was determined on the last day of each 2-wk treatment. Pranlukast, but not seratrodast, tented to increase FEV(1) compared with placebo (2.14 +/- 0.29 versus 1.99 +/- 0.34 L, p = 0.0543). Pranlukast or seratrodast did not affect the PC(20) in comparison with placebo. We conclude that cLTs or TXA2 are not involved in PIB of asthmatics.

Adrenergic beta-Antagonists↗

PubMed1999

Cloning, nucleotide sequence, and disruption of Streptococcus mutans glutathione reductase gene (gor).

We cloned and sequenced the glutathione reductase gene (gor) of an oxygen-tolerant Streptococcus mutans, and constructed a gor-disruption mutant by homologous recombination. The gor gene consisted of 1,350 bp, coding for a protein of 450 amino acid residues. The deduced amino acid sequence of the S. mutans gor gene product showed extensive similarity with those of glutathione reductases from prokaryotes and eukaryotes. Although the mutant could grow aerobically, it showed no growth in the presence of 2 mM diamide, a thiol-specific oxidant. In contrast, growth of the wild-type strain was not significantly inhibited by 2 mM diamide, and glutathione reductase activity was increased 2.2-fold under these conditions. In addition, the level of glutathione reductase activity in the wild-type strain was increased 3.6-fold upon exposure to air, and the elevated level of the enzyme was retained throughout the aerobic growth. Thus, glutathione reductase may be important in protection of S. mutans against oxidative stress.

Amino Acid Sequence↗

PubMed1999

Novel characteristics of Selenomonas ruminantium lysine decarboxylase capable of decarboxylating both L-lysine and L-ornithine.

Lysine decarboxylase (LDC; EC 4.1.1.18) of Selenomonas ruminantium is a constitutive enzyme and is involved in the synthesis of cadaverine, which is an essential constituent of the peptidoglycan for normal cell growth. We purified the S. ruminantium LDC by an improved method including hydrophobic chromatography and studied the fine characteristics of the enzyme. Kinetic study of LDC showed that S. ruminantium LDC decarboxylated both L-lysine and L-ornithine with similar Km and the decarboxylase activities towards both substrates were competitively and irreversibly inhibited by DL-alpha-difluoromethylornithine, which is a specific inhibitor of ornithine decarboxylase (EC 4.1.1.17). We also showed a drastic descent of LDC activity owing to the degradation of LDC at entry into the stationary phase of cell growth.

Amino Acid Sequence↗

PubMed1999

A simple purification method and morphology and component analyses for carotovoricin Er, a phage-tail-like bacteriocin from the plant pathogen Erwinia carotovora Er.

Carotovoricin Er has been isolated as a phage-tail-like bacteriocin from the plant pathogen Erwinia carotovora Er [Kamimiya, S. et al., (1977), Agric. Biol. Chem. 41, 911-912]. However, the fine morphology and structural composition of carotovoricin Er remained to be studied because a large amount of contracted carotovoricin Er were present in the bacteriocin preparations so far obtained. To obtain intact carotovoricin Er and its major parts, we developed simple and efficient purification methods including the use of sucrose density gradient centrifugation in the presence of 10-20% (v/v) ethanol. Electron microscopy for the purified carotovoricin Er showed the presence of a novel antenna-like structure at the proximal end of the phage-tail-like particle, which consisted of a sheath-and-core part, a baseplate, and tail fibers. Contracted sheath and inner core were purified as hollow cylindrical structures with longitudinal lengths of 69 and 174 nm, respectively, and tail fibers were purified as a fibrous structure with length of 63 nm. SDS-polyacrylamide gel electrophoresis showed the presence of single major proteins of 50, 20, and 68 kDa in the isolated sheath, core, and tail fiber, respectively. Three other minor proteins of 46, 44, and 35 kDa were also identified as the structural proteins of carotovoricin Er, which may be the candidate proteins for the antenna-like and the base plate structures. Thus carotovoricin Er consists of at least 6 protein components.

Amino Acid Sequence↗

PubMed1999

Construction of a LukS-PV mutant of a staphylococcal Panton-Valentine leukocidin component having a high LukS-like function.

A 2-residue (D12I13) segment of LukS of a staphylococcal leukocidin component is an essential region for the hemolytic function of LukS towards rabbit erythrocytes in the presence of LukF. Here, we report that insertion of D, I, or AA residue(s) between A11 and E12 residues of LukS-PV, in which the 2-residue D12I13 segment in LukS was absent, confers the full LukS function on LukS-PV, which has only 4% hemolytic activity of that of LukS towards rabbit erythrocytes.

Amino Acid Sequence↗

PubMed1999

Identification of the amino acid residues conferring substrate specificity upon Selenomonas ruminantium lysine decarboxylase.

Lysine decarboxylase (LDC, EC 4.1.1.18) from Selenomonas ruminantium has decarboxylating activities towards both L-lysine and L-ornithine with similar K(m) and Vmax. Here, we identified four amino acid residues that confer substrate specificity upon S. ruminantium LDC and that are located in its catalytic domain. We have succeeded in converting S. ruminantium LDC to an enzyme with a preference in decarboxylating activity for L-ornithine when the four-residue of LDC were replaced by the corresponding residues of mouse ornithine decarboxylase (EC 4.1.1.17).

Amino Acid Sequence↗

PubMed1999

Assembly of Staphylococcus aureus leukocidin into a pore-forming ring-shaped oligomer on human polymorphonuclear leukocytes and rabbit erythrocytes.

Staphylococcal leukocidin consists of two separate proteins, LukS and LukF, which cooperatively lyse human and rabbit polymorphonuclear leukocytes and rabbit erythrocytes. Here we studied the pore-forming properties of leukocidin and the molecular architecture of the leukocidin pore. (1) Leukocidin caused an efflux of potassium ions from rabbit erythrocytes and swelling of the cells before hemolysis. However, ultimate lysis of the toxin-treated swollen erythrocytes did not occur when polyethylene glycols with hydrodynamic diameters of > or = 2.1 nm were present in the extracellular space. (2) Electron microscopy showed the presence of a ring-shaped structure with outer and inner diameters of 9 and 3 nm, respectively, on leukocidin-treated human polymorphonuclear leukocytes and rabbit erythrocytes. (3) Ring-shaped structures of the same dimensions were isolated from the target cells, and they contained LukS and LukF in a molar ratio of 1:1. (4) A single ring-shaped toxin complex had a molecular size of 205 kDa. These results indicated that LukS and LukF assemble into a ring-shaped oligomer of approximately 200 kDa on the target cells, forming a membrane pore with a functional diameter of approximately 2 nm.

Animals↗

PubMed1999

[A case of typical carcinoid accompanied with left atrium myxoma].

A 78-year-old female was admitted to Shizuoka red cross hospital because of an abnormal shadow at the right upper lung field on chest X-ray film. A left atrium myxoma was detected at chest CT scan after admission. Though the lung tumor was well defined and hilar and mediastinal lymph nodes were not swollen at CT scan, the tumor was suspected a small cell carcinoma at the result of trans-bronchoscopic biopsy. Firstly we performed removal of the left atrium myxoma, and two months later, we performed thoracotomy and partial resection of the right upper lobe. The lung tumor was finally diagnosed as a typical carcinoid. We have followed the patient for about 32 months after the operation and there is no evidence of tumor recurrence.

Aged↗

PubMed1999

[Emergency coronary artery bypass grafting in dialysis patients].

Emergency coronary artery bypass surgery was performed in nineteen patients including five chronic hemodialysis patients. In fourteen patients (non-dialysis patients), ten patients required preoperative IABP and four required PCPS for cardiogenic shock. Four patients died (29%); three from LOS and one from sudden death. Most of them (3/4) were preoperative cardiogenic shock. In other five patients (dialysis patients), four patients had conventional CABG, while one received off-pump bypass surgery for calcified aorta and brain complication. All five patients received arterial in situ conduit and continuous hemofiltration in the early postoperative period for controlling water and electrolyte. Two patients died (40%); one from arrhythmia and one from deterioration of original disease (SLE encephalopathy) but no one died from LOS. These methods of surgical modification and perioperative management for chronic hemodialysis patients are considered very useful.

Aged↗

PubMed1998

Complete nucleotide sequence and molecular characterization of the temperate staphylococcal bacteriophage phiPVL carrying Panton-Valentine leukocidin genes.

The staphylococcal Panton-Valentine leukocidin (PVL) genes, [lukS-PV-lukF-PV], exist on the genome of a temperate bacteriophage phiPVL isolated from mitomycin C-induced Staphylococcus aureus V8 (ATCC 49775) (Kaneko, J., Kimura, T., Kawakami, Y., Tomita, T., Kamio, Y., 1997b. Panton-Valentine leukocidin genes in phage-like particle isolated from mitomycin C-treated Staphylococcus aureus V8 (ATCC 49775). Biosci. Biotechnol. Biochem. 61, 1960-1962). In this study, the complete nucleotide sequence of the phiPVL genome was analyzed, and the att sites (attL, attR, and attB) required for site-specific integration of phiPVL into the host chromosome were also determined. The linear double-stranded phiPVL genome comprised 41401bp with 3' staggered cohesive ends (cos) of nine bases and contained 63 ORFs, among which the regulatory proteins involved in DNA replication, structural proteins, a holin, a lysin, an integrase, and dUTPase, were tentatively identified by the comparison of the deduced amino acid sequences and by the analysis of the proteins isolated from phiPVL particles. The [lukS-PV-lukF-PV], attP, and int (integrase gene) of phiPVL were all located very close to one another within a 4.0-kb segment on the genome in the order given, and this segment was located at the center from the left and the right cos sites. In addition, the attP region contained five direct repeat sequences that showed a high degree of homology with the recombinase-binding sites of some other S. aureus bacteriophages. The phiPVL genome was found to integrate into an ORF encoding an unknown protein comprising 725 amino acid residues with two leucine zipper-like motifs.

Amino Acid Sequence↗

PubMed1998

Cough receptor sensitivity to capsaicin and tartaric acid in patients with Mycoplasma pneumonia.

There has been no detailed study of cough sensitivity during acute lower respiratory infection. The aim of this study was to clarify cough sensitivity in Mycoplasma pneumonia, which is a well known acute lower respiratory infection with persistent nonproductive cough. We examined cough sensitivity to inhaled capsaicin and tartaric acid in both the acute and the convalescent phases of Mycoplasma pneumonia, cell differentials in bronchoalveolar lavage fluid, and pathologic findings of transbronchoscopic bronchial biopsy specimens. Although dry cough was observed in all patients during Mycoplasma pneumonia, cough sensitivity in the acute phase [capsaicin: 19.8 (GSEM, 0.214) microM, tartaric acid: 0.26 (GSEM, 0.356) M] were not enhanced compared with those in both control subjects [capsaicin: 27.9 (GSEM, 1.24) microM, tartaric acid: 0.316 (GSEM, 0.079) M] and patients in the convalescent phase [capsaicin: 15.7 (GSEM, 0.219) microM, tartaric acid: 0.50 (GSEM, 0.326) M] when all symptoms including cough had disappeared. The percentage of lymphocytes and neutrophils in bronchoalveolar lavage fluid BALF was significantly greater than in the control subjects, and lymphocyte-dominant bronchitis was observed in biopsied specimens. We conclude that cough threshold to inhaled capsaicin or tartaric acid was not enhanced during acute Mycoplasma pneumonia with lymphocyte-predominant bronchitis. This is the first report examining cough sensitivity in patients with acute lower respiratory infection with pneumonia.

Adult↗