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Biomedical subjects

Y Kamio

Publications and source records attributed to Y Kamio.

At least 37 records · Page 2Linked to original sources
PubMed2000

Coronary artery bypass grafting in dialysis patients.

OBJECTIVE: In dialysis patients, there are two issues to consider, water-electrolyte control and a bypass technique for a calcified aorta. We used continuous hemofiltration for water-electrolyte control and an off-pump bypass with arterial grafting for a calcified aorta. METHODS: We performed coronary artery bypass grafting with extracorporeal circulation in 9 cases and without extracorporeal circulation (off-pump bypass) in 3 cases. In 6 cases, the operation was urgent, and in 6 cases the operation was elective. RESULTS: An average of 3.2 grafts/pt, (the arterial graft: 1.3 grafts/pt) was performed in the pump cases. In the off-pump bypass cases we used arterial grafting only (1.7 grafts/pt). We had 1 early death (sudden death) and 1 hospital death (SLE encephalopathy). One late death due to cerebral bleeding occurred at 2 years later. We used continuous hemofiltration for 2 to 11 days (average 3.9 days) in the pump cases. The off-pump cases could be controlled by conventional hemodialysis. CONCLUSION: Continuous hemofiltration was very easily set up with less interference to the hemodynamics. Using an arterial graft with off-pump bypass, an aortic no-touch technique and water control with conventional hemodialysis were possible.

Adult↗
PubMed2000

Sleeve lobectomy of the middle lobe for hilar lung cancer with accompanying cardiomyopathy and actinomycosis.

The indication for sleeve lobectomy of the middle lobe is limited, because the frequency of cancer occupying both the middle lobe and its bifurcation is low and the more commonly used middle and lower lobectomy is an alternate procedure. However, if a patient has accompanying cardiopulmonary restriction, lung preservation is paramount. We present a patient with hilar lung cancer (TisN0M0) associated with progressive cardiomyopathy, who underwent sleeve lobectomy of the middle lobe; the cancer took a favorable course.

Actinomycosis↗
PubMed2000

Role of the dpr product in oxygen tolerance in Streptococcus mutans.

We have previously identified and characterized the alkyl hydroperoxide reductase of Streptococcus mutans, which consists of two components, Nox-1 and AhpC. Deletion of both nox-1 and ahpC had no effect on the sensitivity of S. mutans to cumene hydroperoxide or H(2)O(2), implying that the existence of another antioxidant system(s) independent of the Nox-1-AhpC system compensates for the deficiency. Here, a new antioxidant gene (dpr for Dps-like peroxide resistance gene) was isolated from the S. mutans chromosome by its ability to complement an ahpCF deletion mutant of Escherichia coli with a tert-butyl hydroperoxide-hypersensitive phenotype. The dpr gene complemented the defect in peroxidase activity caused by the deletion of nox-1 and ahpC in S. mutans. Under aerobic conditions, the dpr disruption mutant carrying a spectinomycin resistance gene (dpr::Spc(r) mutant) grew as well as wild-type S. mutans in liquid medium. However, the dpr::Spc(r) mutant could not form colonies on an agar plate under air. In addition, neither the dpr::Spc(r) ahpC::Em(r)::nox-1 triple mutant nor the dpr::Spc(r) sod::Em(r) double mutant was able to grow aerobically in liquid medium. The 20-kDa dpr gene product Dpr is an iron-binding protein. Synthesis of Dpr was induced by exposure of S. mutans cells to air. We propose a mechanism by which Dpr confers aerotolerance on S. mutans.

Aerobiosis↗
PubMed2000

Gene cloning and molecular characterization of lysine decarboxylase from Selenomonas ruminantium delineate its evolutionary relationship to ornithine decarboxylases from eukaryotes.

Lysine decarboxylase (LDC; EC 4.1.1.18) from Selenomonas ruminantium comprises two identical monomeric subunits of 43 kDa and has decarboxylating activities toward both L-lysine and L-ornithine with similar K(m) and V(max) values (Y. Takatsuka, M. Onoda, T. Sugiyama, K. Muramoto, T. Tomita, and Y. Kamio, Biosci. Biotechnol. Biochem. 62:1063-1069, 1999). Here, the LDC-encoding gene (ldc) of this bacterium was cloned and characterized. DNA sequencing analysis revealed that the amino acid sequence of S. ruminantium LDC is 35% identical to those of eukaryotic ornithine decarboxylases (ODCs; EC 4.1.1.17), including the mouse, Saccharomyces cerevisiae, Neurospora crassa, Trypanosoma brucei, and Caenorhabditis elegans enzymes. In addition, 26 amino acid residues, K69, D88, E94, D134, R154, K169, H197, D233, G235, G236, G237, F238, E274, G276, R277, Y278, K294, Y323, Y331, D332, C360, D361, D364, G387, Y389, and F397 (mouse ODC numbering), all of which are implicated in the formation of the pyridoxal phosphate-binding domain and the substrate-binding domain and in dimer stabilization with the eukaryotic ODCs, were also conserved in S. ruminantium LDC. Computer analysis of the putative secondary structure of S. ruminantium LDC showed that it is approximately 70% identical to that of mouse ODC. We identified five amino acid residues, A44, G45, V46, P54, and S322, within the LDC catalytic domain that confer decarboxylase activities toward both L-lysine and L-ornithine with a substrate specificity ratio of 0.83 (defined as the k(cat)/K(m) ratio obtained with L-ornithine relative to that obtained with L-lysine). We have succeeded in converting S. ruminantium LDC to form with a substrate specificity ratio of 58 (70 times that of wild-type LDC) by constructing a mutant protein, A44V/G45T/V46P/P54D/S322A. In this study, we also showed that G350 is a crucial residue for stabilization of the dimer in S. ruminantium LDC.

Amino Acid Sequence↗
PubMed2000

Covalent linkage of polyamines to peptidoglycan in Anaerovibrio lipolytica.

Spermidine and cadaverine were found to be constituents of the cell wall peptidoglycan of Anaerovibrio lipolytica, a strictly anaerobic bacterium. The peptidoglycan was degraded with the N-acetylmuramyl-L-alanine amidase and endopeptidase into two peptide fragments, peptide I and peptide II, at a molar ratio of 4:1. Peptides I and II were identified as L-alanine-D-glutamic acid(alphacadaverine)gammameso-diaminopimelic acid (DAP)-D-alanine and L-alanine-D-glutamic acid(alphaspermidine)gammameso-DAP-D-alanine, respectively. The N(1)-amino group of spermidine was linked to the alpha-carboxyl group of the D-glutamic acid residue of peptide II.

Cadaverine↗
PubMed2000

Effect of oral mexiletine on the cough response to capsaicin and tartaric acid.

BACKGROUND: The effect of the orally active local anaesthetic mexiletine on the cough response to two different tussive agents, a C-fibre ending stimulator capsaicin and a chemostimulant tartaric acid, was examined in normal subjects. METHODS: The cough threshold, defined as the lowest concentration of capsaicin (C(5)-CP) or tartaric acid (C(5)-TA) causing five or more coughs, and histamine induced bronchoconstriction were measured three hours after a single oral dose of 300 mg mexiletine or placebo in 14 normal subjects. RESULTS: Mexiletene in a mean (SE) serum concentration of 0.99 (0. 04) microg/ml significantly increased C(5)-TA from a geometric mean (SE) of 32.0 (1.27) mg/ml with placebo to 49.9 (1.34) mg/ml, but C(5)-CP did not differ significantly between treatment with mexiletine (12.2 (1.33) microM) and placebo (14.9 (1.23) microM). CONCLUSIONS: These results suggest that the cough response to capsaicin and tartaric acid may be mediated in part via different neural pathways.

Administration, Oral↗
PubMed2000

Effect of losartan, a type 1 angiotensin II receptor antagonist, on bronchial hyperresponsiveness to methacholine in patients with bronchial asthma.

It is unclear whether angiotensin II receptors are involved in bronchial hyperresponsiveness in asthmatic patients. We examined the effect of losartan, a specific angiotensin II type 1 (AT1) receptor antagonist, on bronchial responsiveness to inhaled methacholine in eight patients with stable asthma. Bronchial responsiveness to methacholine, assessed as the concentration of methacholine producing a 20% fall in FEV(1) (PC(20)-FEV(1)) and a 35% fall in standardized partial expiratory flow at 40% of FVC (PC(35)-PEF(40)), was measured on two occasions 2 wk apart. Losartan (50 mg once a day) or a placebo was orally administered for 1 wk before methacholine provocation test in a double-blind, randomized, crossover fashion. Although the PC(20)-FEV(1) values after placebo (2.037 [geometric standard error of the mean, GSEM = 0.210] mg/ml) and losartan (2.098 [GSEM, 0.239] mg/ml) were identical (p = 0.840), the geometric mean PC(35)-PEF(40) values significantly (p = 0.034) increased from 0.258 (GSEM, 0.156) mg/ml with placebo to 0.456 (GSEM, 0.186) mg/ml with losartan. We conclude that AT1 receptors are involved in bronchial hyperresponsiveness in asthmatic patients. This is the first report demonstrating the involvement of AT1 receptors in bronchial asthma.

Adult↗
PubMed2000

Identification of a new gene responsible for the oxygen tolerance in aerobic life of Streptococcus mutans.

Alkyl hydroperoxide reductase in Streptococcus mutans consists of two components, Nox-1 and AhpC. Deletion of nox-1 and ahpC in a double mutant as well as the wild-type of Streptococcus mutans can form colonies in the presence of air to the same extent. The evidence suggested the presence of some other antioxidant system(s) independent of the Nox-1/AhpC system in the bacterium. Here we identified a new antioxidant gene (dpr) and the gene product (Dpr) which complements the defect of peroxidase activity caused by the deletion of nox-1 and ahpC in S. mutans. The dpr-disruption mutant of S. mutans could form colonies anaerobically but not aerobically.

Aerobiosis↗
PubMed2000

High expression of the second lysine decarboxylase gene, ldc, in Escherichia coli WC196 due to the recognition of the stop codon (TAG), at a position which corresponds to the 33th amino acid residue of sigma38, as a serine residue by the amber suppressor, supD.

Escherichia coli WC196, which was obtained from the strain W3110 by nitrosoguanidine mutagenesis as an overproducer of lysine, produced approximately twenty times more cadaverine than did W3110, and had a twenty fold higher level of rpoS gene product, sigma38, than in W3110. Both WC196 and W3110 had a stop codon (TAG) in rpoS at position which corresponds to the 33th residue of sigma38 protein. In addition, WC196 but not W3110 had a mutation in the gene encoding Ser-tRNA (SerU), called, supD. Analysis of the amino acid sequence of a sigma38 preparation from WC196 showed that the 33th residue of sigma38 is a serine residue. The deltarpoS deltacadA mutant of E. coli W3110 harboring the plasmid containing rpoS, in which the TAG codon was converted to a TCG codon for serine-33 residue of sigma38, expressed a significant amount of Ldc and accumulated a large amount of sigma38. However, the deltarpoS deltacadA mutant of W3110 with the plasmid containing the intact rpoS from W3110 could synthesize neither sigma38 nor Ldc significantly.

Amino Acid Sequence↗
PubMed2000

Prophage, phiPV83-pro, carrying panton-valentine leukocidin genes, on the Staphylococcus aureus P83 chromosome: comparative analysis of the genome structures of phiPV83-pro, phiPVL, phi11, and other phages.

Staphylococcus aureus P83 has Panton-Valentine leukocidin (PVL)-like genes, lukM and lukF-PV. Here, lukM and lukF-PV genes were found on the genome of a prophage, which was designated as phiPV83-pro. The precise genome size was 45,636 bp with att core sequences of 10 base pairs. Sixty-four ORFs were identified on the phiPV83-pro genome, including two extra operons, lukM-lukF-PV and orfs63-64. The lukM-lukF-PV cluster was located 2.1 kb upstream of the attL site. The most striking feature of the phiPV83-pro genome was a constituent of at least 4 regions from phi11, phiPVL, and other phages, i.e., (i) att sites identical with those of phi11, (ii) a cos sequence and the genes encoding packaging and head proteins of phiPVL (occupied half region of phiPV83-pro), and (iii) the other two regions which showed no significant similarity with known phages (occupied about 40% of phiPV83-pro). Furthermore, two insertion sequences, ISSA1 and ISSA2 were integrated into attL site and orf44, respectively. PhiPV83-pro was not induced as phage particles from S. aureus P83 regardless of its treatment with mitomycin C. The insertion of ISSA1 into the attL site was one of the reasons of the failure of the induction of the phage particles by mitomycin C treatment of the strain P83.

Amino Acid Sequence↗
PubMed2000

Tyrosine72 residue at the bottom of rim domain in LukF crucial for the sequential binding of the staphylococcal gamma-hemolysin to human erythrocytes.

Staphylococcal bi-component cytotoxins, leukocidin (Luk), Panton-Valentine leukocidin (PVL), and gamma-hemolysin (Hlg) consist of LukF and LukS, LukF-PV and LukS-PV, and LukF and Hlg2, respectively, and Luk and Hlg share LukF. LukF-PV can not substitute for LukF for Hlg, despite 73% identity in amino acid sequence and close similarity in the 3-dimensional structure between them. Here, we demonstrated that the absence of hemolytic activity of LukF-PV in cooperation with Hlg2 is due to the failure of the binding of LukF-PV to human erythrocytes. We identified Y72 residue at the bottom of rim domain in LukF as the crucial residue for its binding, which is a prerequisite to the subsequent binding of Hlg2 to human erythrocytes. The data obtained showed that a mutant of LukF-PV in which T71 residue was replaced by the corresponding residue of LukF, Y72, endowed LukF-PV with the binding capability to human erythrocytes which was accompanied by its hemolytic activity in the presence of Hlg2.

Amino Acid Substitution↗
PubMed2000

Purification and some properties of high-molecular-weight xylanases, the xylanases 4 and 5 of Aeromonas caviae W-61.

Aeromonas caviae W-61 produces multiple extracellular xylanases, the xylanases 1, 2, 3, 4, and 5 [Nguyen, V. D. et al., Biosci. Biotechnol. Biochem., 56, 1708-1712 (1993)]. Here we purified and characterized high-molecular-weight xylanases, the xylanases 4 and 5 from the culture fluids of the bacterium. The purified xylanases 4 and 5, which had molecular masses of 120 and 140 kDa, respectively, were endo-beta-1,4-xylanases with similar enzymatic properties except for trans-xylosidase activity. The xylanase 4 showed a prominent transxylosidase activity when xylotriose and xylotetraose were used as the substrates, while the xylanase 5 had little transxylosidase activity under the same conditions. Protein sequencing indicated that the xylanase 4 was a C-terminally-truncated xylanase 5, suggesting that the C-terminal truncation of the xylanase 5 may endow the enzyme with transxylosidase activity.

Aeromonas↗
PubMed2000

[Thymic carcinoma successfully treated by a combination of intra-arterial infusion chemotherapy and surgery].

A 47-year-old man with thymic carcinoma that had invaded the inner pericardium and adhered to the superior vena cava and right atrium at first operation was treated with intra-arterial infusion chemotherapy (nedaplatin and adriamycin) through the internal thoracic artery. After 2 courses of modified ADOC therapy (nedaplatin, adriamycin, vincristine, and cyclophosphamide), chest computed tomographic (CT) scans revealed a 47% reduction in tumor size. No adverse effects due to the anticancer drugs were observed. Resection of the tumor included part of the upper lobe of the right lung and pericardium. Examination of resected tumor tissue specimens revealed viable cancer cells and extensive fibrosis. The diagnosis was thymic anaplastic carcinoma. We concluded that intra-arterial selective infusion chemotherapy utilizing an ADOC regimen can be of value as a treatment for thymic carcinoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Dual access to semantics in autism: is pictorial access superior to verbal access?

The main aim of the present study was to compare pictures and words with respect to access to semantic systems in autism using a semantic priming paradigm. A word completion task was conducted using both within-modality (word word, WW) and cross-modality (picture word, PW) conditions on a group of high-functioning adolescents and adults with autism (N = 20) and a control group (N = 20) matched on chronological age, mental age, Verbal IQ and Performance IQ. Both groups showed semantic priming effects in both modality conditions. generating significantly more responses for related prime-target pairs than for unrelated pairs. Although the control group performed similarly on both priming tasks, the autistic group performed significantly better on a PW task than on a WW task. These findings suggest the possible advantage of pictures over words in access to semantics in autism. The theoretical implications are discussed in terms of functional asymmetry between verbal and pictorial semantic operations that may be specific to autism.

Adolescent↗
PubMed2000

Comparison between tidal breathing and dosimeter methods in assessing cough receptor sensitivity to capsaicin.

OBJECTIVE: Dosimeter method and tidal breathing method have been used to assess cough sensitivity to inhaled capsaicin, a C-fibre ending stimulator. The aim of the present study was to evaluate the repeatability of and the agreement between the two methods. METHODOLOGY: Cough threshold, the lowest concentration of capsaicin causing five or more coughs, was measured twice 1-3 weeks apart by each method in 26 normal subjects. Increasing concentrations of capsaicin were inhaled by a single breath in the dosimeter method or by 15 s tidal breathing in the tidal breathing method in 1 min intervals. RESULTS: Coefficients of repeatability of the cough threshold measurement were 1.89 and 2.71 doubling concentration in the tidal breathing method and the dosimeter method, respectively, suggesting good repeatability in the cough threshold measurement by both methods. The cough threshold was significantly (P < 0.0001) greater by 1.75 doubling concentration on the dosimeter method than the tidal breathing method. The coefficient of agreement between the two methods was 2.53 doubling concentration. Five subjects complained of burning sensation in the throat in the dosimeter method but no patient complained about the tidal breathing method (P < 0.05). CONCLUSIONS: Although the agreement between the two methods was considered to be good, higher concentrations of capsaicin solution were required to determine the cough threshold in the dosimeter method, resulting in an unpleasant sensation in the throat.

Administration, Inhalation↗
PubMed2000

Molecular biology of oxygen tolerance in lactic acid bacteria: Functions of NADH oxidases and Dpr in oxidative stress.

Lactic acid bacteria including Streptococcus mutans lack cytochromes and heme-containing proteins. Most lactic acid bacteria also lack catalase. However, they can grow in the presence of air. In view of the defense against oxygen toxicity, the lack of catalase in lactic acid bacteria is not always consistent with its aerotolerance. Mechanisms, by which lactic acid bacteria establish their growth in air, are therefore an active area of investigation. We identified two kinds of NADH oxidase genes, nox-1 and nox-2 for H2O2-forming NADH oxidase (Nox-1) and H2O-forming NADH oxidase (Nox-2), respectively, in S. mutans and found that Nox-1 is homologous with flavoprotein component, AhpF, of Salmonella typhimurium alkyl hydroperoxide reductase (AhpR), consisting of AhpF and AhpC. We also identified ahpC which is homologous with ahpC of S. typhimurium, upstream of nox-1 in S. mutans. In the first and second parts of this article, we will refer to the role of Nox-1 which acts together with AhpC as bi-component peroxidase system in S. mutans, catalyzing the NADH-dependent reduction of organic hydroperoxides or H2O2 to their respective alcohol and/or H2O. We will also refer to the role of Nox-2 in carbohydrate metabolism of S. mutans in its aerobic life. Nox-2 was found to be involved in regenerating NAD+, which is required for glycolysis in S. mutans. While studying nox-1 and ahpC double deletion mutant of S. mutans, we found that the mutant still showed the same level peroxide tolerance as did the wild-type strain. The finding suggested the existence of another antioxidant system in addition of Nox-1 and AhpC in S. mutans. We identified a new gene, dpr (for Dps-like Peroxide Resistance gene) and its product, Dpr, as an iron-binding protein which is responsible for oxygen tolerance in S. mutans. In the third part of this article, we will refer to the current status of knowledge of molecular cloning of dpr, the characteristics of dpr-disruption mutants, and a mechanism by which Dpr confers aerotolerance to S. mutans.

Journal Article↗
PubMed1999

Isolation and characterization of a mannan-binding lectin from the freshwater cyanobacterium (blue-green algae) Microcystis viridis.

Microcystis viridis NIES-102 strain, a unicellular freshwater bloom-forming cyanobacterium, showed transient hemagglutinating activity in laboratory culture during stationary phase under nonaeration conditions. However, the hemagglutinating activity which was inhibited with yeast mannan could not be observed during culture with aeration. A mannan-binding lectin named MVL was isolated with the assay of the hemagglutinating activity against rabbit erythrocytes from the cyanobacterium by successive hydrophobic and gel filtration chromatography. MVL was composed of a single polypeptide of 13 kDa. The gene (mvl) for MVL was cloned from a genomic DNA of NIES-102 strain as a template, and its sequence was determined. The deduced amino acid sequence showed that MVL consisted of 113 amino acid residues and was composed of two tandemly repeated homologous domains of 54 amino acid residues. MVL showed no sequence homology to any other lectins or proteins.

Amino Acid Sequence↗