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M Konno

Publications and source records attributed to M Konno.

At least 19 recordsLinked to original sources
PubMed1992

The crystal structure of muscle phosphoglucomutase refined at 2.7-angstrom resolution.

A model of rabbit muscle phosphoglucomutase was refined at 2.7-A resolution by using two heavy atom derivatives for initial phasing and standard refinement procedures, including molecular replacement averaging about a 2-fold axis and dynamic simulation: final R-factor, 0.223 (no solvent modeling); RMS deviation from standard bond lengths and angles, 0.020 A and 3.6 degrees, respectively (all 8658 nonhydrogen atoms plus 36,953 reflections (F/sigma greater than or equal to 3) between 8- and 2.7-A resolutions); average of individually refined atomic B-factors, 40 A2 (all atoms) and 30 A2 (all atoms in domains I-III). An H-bonding scheme with 538 main chain H-bonds for the two monomers in the asymmetric unit and probable ligands for six uranyl ions in one heavy atom derivative is given. The monomer contains 42 strands/helices arranged into four alpha/beta-domains. Each of the first three domains contains an alpha 3 beta 4 alpha 1 motif, where the topology of beta 4 is 2,1,3,4:[arrows: see text] which is a topology not encountered in an extensive search among known protein structures. A spatial similarity is observed between corresponding residues in the three repetitions of this motif per monomer, but the minimal mutational distance between spatially corresponding residues is not statistically significant. The loop between the antiparallel strands in each of these domains is an important feature of the active site. In domain IV, beta-sheet topology is 2,1,3,4,5,6:[arrows:see text]. Noncovalent domain/domain interactions within the monomer are greatest between adjacent domains along the polypeptide chain, which are not substantially interdigitated and can be cleanly disengaged by altering the phi/psi torsional angles of three uniquely positioned residues in the model. The observed hierarchy of noncovalent interactions between structural units within the crystal, based on a semi-empirical paradigm, suggests that monomer-monomer contacts within the asymmetric unit are formed during growth of the lattice and provides a rationale for some of the diffraction characteristics of phosphoglucomutase crystals. An unusually deep crevice involving 58 residues is formed by the head-to-tail, twisted semicircular arrangement of the four domains of the monomer that places no atom more than 12 A from the water-accessible surface. The active site of the enzyme is extensively buried at the bottom of this crevice, at the approximate confluence of the four domains. Other features of the active site, including the surrounding helical dipoles, and the metal-ion binding pocket are described, together with structure/function comparisons with a number of other enzymes.

Amino Acid Sequence↗
PubMed1992

In vitro validation of a thermodilution right ventricular ejection fraction method.

A thermodilution catheter and computer system has been developed to measure right ventricular ejection fraction and volumes. To evaluate the performance of this method, the thermodilution system was evaluated in an in vitro pulsatile flow model. Thermodilution measurements of ejection fraction (EF), cardiac output (CO), stroke volume (SV), end-diastolic volume (EDV), and end-systolic volume (ESV) were compared with known values in a pulsatile flow bench. Thermodilution EF measurements correlated very well with the pulsatile flow model (r2 = 0.95, m [slope] = 0.85, SEE = 4.0 EFU). Thermodilution CO and SV were highly predictive of actual pulsatile flow (r2 = 0.99, m = 0.99, SEE = 187 ml/min and r2 = 0.98, m = 0.96, SEE = 2.5 ml, respectively). Thermodilution end-diastolic and end-systolic volume measurements resulted in low mean eror, -1.8% and 0.6%, respectively. The standard deviations of the error for EDV and ESV were 11.0% and 16.4%. The thermodilution measurements were repeatable, with CO, SV, and EF coefficients of variation of 3.2%, 3.3%, and 4.7%, respectively. EDV and ESV were slightly more variable, with coefficients of variation of 5.5% and 7.2%, respectively.

Cardiac Catheterization↗
PubMed1992

Rapid detection of the mecA gene in methicillin-resistant staphylococci by enzymatic detection of polymerase chain reaction products.

In order to identify methicillin-resistant staphylococci from clinical sources with ease and reliability, enzymatic detection of polymerase chain reaction (ED-PCR) was applied. ED-PCR is based on the capture of amplified products via biotin-streptavidin affinity and the detection of an incorporated hapten in amplified products with an enzyme-linked antibody. In order to identify methicillin-resistant staphylococci of all species, a 150-bp fragment of the mecA gene was targeted for ED-PCR. After PCR was performed with a pair of biotin and dinitrophenol 5'-labeled primers, the reaction mixture was applied to a microtiter well precoated with streptavidin. Thereafter, bound PCR products were detected colorimetrically with alkaline phosphatase-conjugated anti-dinitrophenol antibody. The extraction of DNA from staphylococcal cells for PCR was simplified so that it could be performed within one tube. The total assay, including PCR, took less than 3 h. The sensitivity of mecA gene detection ranged from greater than 5 x 10(2) CFU per tube for Staphylococcus aureus to greater than 5 x 10(3) CFU per tube for Staphylococcus epidermidis. Genotyping results obtained by ED-PCR of 161 tested strains from the colonies (97 strains of S. aureus and 64 strains of coagulase-negative staphylococci) were compared with the phenotypic susceptibilities of the strains to oxacillin. The results of ED-PCR showed excellent agreement with the MICs of oxacillin with very few exceptions; only one strain of S. aureus and two strains of coagulase-negative staphylococci were found to possess the mecA gene, which was discrepant with their phenotypes. Fifty-five blood culture samples were also tested by ED-PCR. For staphylococcal isolates in 33 of the cultures, oxacillin MICs were >4 microgram/ml; 31 of the 33 staphylococcal isolates were determined by ED-PCR to be mecA gene positive. These results suggest that ED-PCR can be used with reasonable confidence in the clinical microbiological laboratory.

Alkaline Phosphatase↗
PubMed1992

Detection of Epstein-Barr virus sequences in patients with Kawasaki disease by means of the polymerase chain reaction.

We used a selective DNA amplification technique to detect Epstein-Barr virus (EBV) DNA in peripheral blood mononuclear cells from patients with Kawasaki disease (KD). By means of the polymerase chain reaction EBV sequences were indentified directly in 21 (60%) of 35 KD patients within 2 weeks after the onset of KD. Furthermore, EBV sequences were detected in all of 6 repeatedly tested patients with KD within 3 months after disease onset. In contrast, only 2 (12%) of 17 control DNA samples were polymerase chain reaction positive. These results indicate that an unusual EBV-cell interaction may exist in KD.

Child, Preschool↗
PubMed1992

[Two cases of congenital cardiac anomaly associated with esophageal atresia].

Two cases of congenital cardiac anomaly associated with esophageal atresia and tracheo-esophageal fistula were presented. One case was HLHS, and the other was TAPVR. Esophageal procedures were performed earlier than cardiac procedures in both cases. Primary anastomosis for esophageal atresia just after birth in the latter case. Corrective procedures for cardiac anomalies were performed at 36 days and 35 days after birth, respectively. The HLHS case died perioperatively and the TAPVR case survived the operation and is alive one year postoperatively.

Esophageal Atresia↗
PubMed1992

[A case of straddling tricuspid valve associated with VSD].

A case of straddling tricuspid valve associated with VSD was presented, who was diagnosed as VSD with pulmonary hypertension but not diagnosed as straddling in preoperative state. Two-dimensional echocardiography did not demonstrate a small right ventricle and overriding of tricuspid valve to the ventricular septum. Operative findings were as follows; the VSD was common A-V canal type and anomalous chordae of septal leaflet of tricuspid valve crossed through the VSD and attached to the contralateral side of the ventricular septum. We tried to preserve the anomalous chordae to prevent tricuspid regurgitation, so that we carried out patch closure of VSD. To avoid injury conduction system stitches were placed from upper margin of the VSD, and to keep away tricuspid regurgitation we plicated a depression of septal leaflet which caused by anomalous chordae in VSD patch closure. In postoperative state, A-V block did not arise and tricuspid regurgitation was shown a little as well as preoperative state.

Heart Septal Defects, Ventricular↗
PubMed1991

Enhancement of the grafting efficiency of transplanted marrow cells by preincubation with interleukin-3 and granulocyte-macrophage colony-stimulating factor.

To improve the grafting efficiency of transplanted murine hematopoietic progenitors, we briefly preincubated mouse bone marrow cells with interleukin-3 (IL-3) or granulocyte-macrophage colony-stimulating factor (GM-CSF) ex vivo before their transplantation into irradiated recipients. This treatment was translated into an increase in the seeding efficiency of colony-forming unit-spleen (CFU-S) and CFU-GM after transplantation. Not only was the concentration of CFU-S in the tibia increased 2 and 24 hours after transplantation, but the total cell number and CFU-S and CFU-GM concentrations were persistently higher in IL-3- and GM-CSF-treated groups 1 to 3 weeks after transplantation. In addition, the survival of animals as a function of transplanted cell number was persistently higher in IL-3- and GM-CSF-treated groups compared with controls. The data indicate that the pretreatment of marrow cells with IL-3 and GM-CSF before transplantation increases the seeding efficiency of hematopoietic stem cells and probably other progenitor cells after transplantation. This increased efficiency may be mediated by upward modulation of homing receptors. Therefore, ex vivo preincubation of donor marrow cells with IL-3 and GM-CSF may be a useful tactic in bone marrow transplantation.

Animals↗
PubMed1991

[Cytogenetic studies on 53 childhood acute nonlymphocytic leukemia].

Cytogenetic study in 53 children (aged less than 15 years) with acute non-lymphocytic leukemia (ANLL) were studied. The cytogenetic findings were compared with those of ANLL patients (136 aged less than 19 years and 747 aged over 20 years) in the Fourth International Workshop on Chromosomes in Leukemia (IV IWCL) and also with those of childhood acute lymphoblastic leukemia (ALL) cases (previously reported as our 124 ALL case). Of the ANLL patients, 77.4% had acquired chromosomal clonal abnormalities. As abnormalities, t(15;17), all cases which were seen in M3 or M3V cases, t(8;21), which was seen in M1 or M2, and rearrangements of 11q23, which were seen in M5, were more frequently seen than was reported at the IV IWCL (20.8%, 17.0% and 7.5% vs 6.3%, 6.3% and 3.2% respectively). 5q-, monosomy 7, t(6;9) and t(9;22), which have been noted previously in this disease, were not seen. Besides structural abnormalities, some cytogenetic differences in numerical abnormality between ALL and ANLL were observed as follows: 1) Hyperdiploidy of greater than 51 chromosomes noted in ALL was not found in ANLL. 2) Isolated trisomy 8 was frequently found in ANLL, but not in ALL. 3) Loss of a sex chromosome was frequently found in ANLL, but not in ALL. Our study revealed a different frequency of non-random chromosome abnormality in children with ANLL as compared with that of adults, and clarified the differences in numerical abnormalities, as well as structural abnormalities, between ALL and ANLL.

Adolescent↗
PubMed1991

[Significance of the 14q32 translocations in childhood acute lymphoblastic leukemia].

To assess the frequency and significance of 14q32 translocation abnormalities in childhood acute lymphoblastic leukemia (ALL) and the differences between the clinical and cytogenetic features of patients with the 8; 14 translocation and those of patients with other 14q32 translocations, we analyzed our experience with 124 consecutive cases with completely banded karyotype. Eight cases (6.5%) with 14q32 translocation were identified :5 with the 8; 14 translocation and 3 with other 14q32 translocations. As compared with ALL children lacking 14q32 translocations, these 8 cases had a higher serum lactic dehydrogenase (LDH) level, more L3 (FAB classification), and a poorer outcome. On the other hand, in comparison with ALL patients with other 14q32 translocations, patients with the 8:14 translocation were likely to be younger (median age 4.5 years vs 10.4 years), to have a higher serum LDH level (median 5832 IU/l vs 504 IU/l), to have more L3 (3/5 vs 0/3), to have a higher induction failure rate (4/5 vs 1/3), and to have more partial duplication of the long arm of chromosome 1 (4/5 vs 0/3). These results helped clarify the characteristic features of ALL children with 14q32 translocations and showed that ALL children with the 8 ; 14 translocation have different clinical and cytogenetic findings from those of ALL children with other 14q32 translocations.

Adolescent↗
PubMed1991

[Inhibition of hemopoiesis by nitrous oxide].

Inhibition of hemopoiesis by nitrous oxide was studied in mice and the following results were obtained. 1) During exposure to N2O, the numbers of pluripotent hemopoietic stem cells (CFU-S) and granulocyte-macrophage progenitor cells (GM-CFC) decreased significantly in the murine spleen and bone marrow, but the former more than the latter. 2) The recovery of CFU-S and GM-CFC was delayed in mice that were given low-dose irradiation followed by continuous exposure to N2O. The delay of recovery was significantly more in the spleen than in the bone marrow. 3) The levels of serum granulocyte-macrophage colony stimulating factor (CSF) in N2O exposed mice, induced by endotoxin, decreased significantly compared with those of control mice. Prolonged N2O administration to mice appears to impair the hemopoietic inductive microenvironment as well as hemopoietic stem cells and hence results in hemopoietic death and delay of hemopoietic recovery after irradiation.

Animals↗
PubMed1990

Homology of mecA gene in methicillin-resistant Staphylococcus haemolyticus and Staphylococcus simulans to that of Staphylococcus aureus.

A penicillin-binding protein of molecular weight 76,000 inducible by beta-lactams was detected in methicillin-resistant Staphylococcus haemolyticus and Staphylococcus simulans. DNA from these strains hybridized to the mecA gene from Staphylococcus aureus; however, the chromosomal HindIII fragments containing the mecA genes were 3.4 kilobases in S. haemolyticus and 4.3 kilobases in S. simulans.

Bacterial Proteins↗
PubMed1990

In vitro activity of LJC10,627, a new carbapenem antibiotic with high stability to dehydropeptidase I.

The in vitro activity of LJC10,627, a new carbapenem, was compared with those of imipenem and ceftazidime. LJC10,627 had broad-spectrum activity against gram-positive and gram-negative clinical isolates. The MICs of this compound for 90% of members of the family Enterobacteriaceae tested (MIC90s), including strains resistant to ceftazidime, ranged from 0.1 to 25 micrograms/ml. LJC10,627 inhibited Pseudomonas aeruginosa at an MIC90 of 3.13 micrograms/ml; it thus was twofold more active than imipenem. This compound inhibited Haemophilus, Neisseria, and Branhamella species at MIC90s of 3.13, 0.1, and 0.1 micrograms/ml, respectively. LJC10,627 was two- to fourfold less active than imipenem against methicillin-susceptible Staphylococcus aureus and Staphylococcus epidermidis at MIC90s of 0.1 and 0.39 microgram/ml. However, the compound was found to be twofold more active than imipenem against Bacteroides fragilis at an MIC90 of 1.56 microgram/ml. LJC10,627 was very stable to various beta-lactamases except for Xanthomonas maltophilia oxyiminocephalosporinase type II. LJC10,627 was minimally hydrolyzed by swine renal dehydropeptidase I; its residual activity was 93.0% after 2 h. Killing kinetics of this compound for Escherichia coli and Pseudomonas aeruginosa showed that bactericidal action occurred at concentrations above the MIC (0.05 and 0.39 microgram/ml, respectively). LJC10,627 had a high affinity for penicillin-binding proteins 2, 4, and 1B(s) of Escherichia coli and Pseudomonas aeruginosa and penicillin-binding proteins 1 and 4 of Staphylococcus aureus.

Animals↗
PubMed1990

Nucleotide sequence and characterization of the Staphylococcus aureus norA gene, which confers resistance to quinolones.

The norA gene cloned from chromosomal DNA of quinolone-resistant Staphylococcus aureus TK2566 conferred relatively high resistance to hydrophilic quinolones such as norfloxacin, enoxacin, ofloxacin, and ciprofloxacin, but only low or no resistance at all to hydrophobic ones such as nalidixic acid, oxolinic acid, and sparfloxacin in S. aureus and Escherichia coli. The 2.7-kb DNA fragment containing the norA gene had a long open reading frame coding for 388 amino acid residues with a molecular weight of 42,265, which was consistent with the experimental value of about 49,000 obtained on DNA-directed translation. The deduced NorA polypeptide has 12 hydrophobic membrane-spanning regions and is partly homologous to tetracycline resistance protein and sugar transport proteins. The uptake of a hydrophilic quinolone, enoxacin, by S. aureus harboring a plasmid carrying the norA gene was about 50% that by the parent strain lacking the plasmid, but it increased to almost the same level as that by the latter strain with carbonyl cyanide m-chlorophenyl hydrazone. On the other hand, the uptake of a hydrophobic quinolone, sparfloxacin, was similar in the two strains. These results suggest that the NorA polypeptide may constitute a membrane-associated active efflux pump of hydrophilic quinolones.

Amino Acid Sequence↗
PubMed1990

Effects of prolonged nitrous oxide exposure on hemopoietic stem cells in splenectomized mice.

We have demonstrated in previous papers that prolonged nitrous oxide exposure suppresses murine hemopoiesis more in the spleen than in the bone marrow and that this is caused by the suppression of the hemopoietic supportive activity of the microenvironment. In the present study, we used splenectomized mice as an experimental model to investigate the direct effect on bone marrow function of prolonged nitrous oxide inhalation. All of the experimental mice were splenectomized at the age of 4 wk. Half of the experimental mice were continuously exposed to 50% nitrous oxide, and the remainder were continuously exposed to air as controls, starting 3 wk after splenectomy and lasting 14 days, and the numbers of pluripotent hemopoietic stem cells (CFU-S) and granulocyte-macrophage progenitor cells (GM-CFC) in bone marrow were counted. The numbers of pluripotent hemopoietic stem cells and granulocyte-macrophage progenitor cells in the bone marrow of mice exposed to air showed no significant change. The numbers of these two types of cells found in nitrous oxide-exposed mice were approximately 60% of control levels. These data are almost the same as our previously reported bone marrow data obtained in nonsplenectomized mice exposed to nitrous oxide for 14 days. The present results suggest that the marked decrease in the number of splenic hemopoietic stem cells in our previous data is not a result of migration of the cells to bone marrow, and that nitrous oxide directly affects murine bone marrow hemopoiesis.

Animals↗
PubMed1990

[Clinical and cytogenetic features in childhood acute lymphoblastic leukemia with 1; 19 translocation].

We studied the clinical and cytogenetic features of 14 acute lymphoblastic leukemia (ALL) patients with 1; 19 translocation. Ten patients had poor prognostic factors such as age over 10 years, hyperleukocytosis over 5 X 10(4)/microliters or high serum lactic dehydrogenase levels over 5,000 IU/l. Two patients had relapsed within 12 months after the onset, but their 5-year survival rate was 84.6%. Cytogenetically, 6 of 14 patients had multiple subclones. Two had the clones with hyperdiploidy greater than 50 chromosomes, which was known to be one of the favorable prognostic factors in childhood ALL. These findings show ALL children with 1; 19 translocation have a more favorable outcome in spite of some high-risk features than hitherto been thought.

Adolescent↗
PubMed1990

Murine spleen culture: homing of hemopoietic progenitor cells to spleen is not mediated by a similar mechanism to that in marrow.

We have previously shown that in long-term bone marrow cultures (LTMC) the specific recognition and binding of hemopoietic stem cells to stroma, which we call "homing," is mediated by a recognition mechanism involving a surface membrane lectin with galactosyl and mannosyl specificities. Subsequent in vivo studies in lethally irradiated mice confirmed that homing to the marrow similarly involves a galactosyl- and mannosyl-specific recognition mechanism. However, these in vivo studies suggested that homing of hemopoietic progenitor cells to spleen was based upon a different molecular recognition mechanism. In the present study splenic homing was investigated in a cell culture system composed of an adherent layer of splenic stromal cells inoculated with stroma-free stem cells from the supernate of LTMC. In this system, splenic stroma supported proliferation and differentiation of hemopoietic precursors for a few weeks. When stem cells were added to the cultures in the presence or absence of inhibitory concentrations of neoglycoprotein reagents specific for galactosyl, mannosyl, or fucosyl lectins, the pattern of production of total cells, pluripotential stem cells (CFU-S), and granulocyte-macrophage committed progenitors (CFU-GM) remained the same. These data support our in vivo observations that homing of stem cells to splenic stroma is not mediated by a surface lectin with galactosyl and mannosyl specificities as it is in bone marrow, but rather by a different molecular mechanism.

Animals↗