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Biomedical subjects

Yutaka Ito

Publications and source records attributed to Yutaka Ito.

At least 19 recordsLinked to original sources
PubMed2006

Velocity-dependent EMG activity of masseter and sternocleidomastoideus muscles during a ballistic arm thrusting movement.

Two experiments were conducted to investigate the functional relationship between the general somatic motor function and the oral motor function. In Experiment 1, we analyzed the relationship between the amount of masseter muscle (MSS) activity and the velocity of a ballistic, 'karate-do' arm thrusting movement (ThrMov). ThrMov velocity was measured from video images taken with a high-speed CCD camera at a frequency of 500Hz. EMGs of MSS and sternocleidomastoideus (SCM) muscles as well as other related muscles were recorded simultaneously with video images in 6 varsity 'karate-do' athletes. Pearson's correlation coefficients were calculated between EMG amplitude and movement velocity. EMG activity of MSS as well as the other muscles increased as a function of ThrMov velocity in all participants, as evidenced by highly significant (p<.01) correlation coefficients, ranging from .64 to .87 (mean: .75). MSS EMG activity attained during ThrMovs performed at maximum velocity ranged between 14.6% and 113.8% of this muscle's MVC (45.7+/-39.3% MVC, mean+/-SD). SCM was also strongly active and closely associated with MSS. Besides changes in amount of EMG activity, it was further found that R-MSS EMG onset progressively shifted to the earlier phase of the ThrMov as ThrMov velocity increased. EMG onset time of R-MSS as well as R- and L-SCMs was negatively correlated with ThrMov velocity; when performed at maximum velocity MSS activation preceded the start of ThrMov by more than 100ms, whereas MSS was recruited last at approximately 150ms after the start of ThrMov when performed at moderate speed ( approximately 50% of maximum). In Experiment 2, the effects of head movement relative to the trunk on R-MSS and SCMs EMG activity were tested in both gazing and sidelong glancing conditions. A much smaller head rotation relative to the trunk was necessary during the ThrMov in the sidelong glancing condition compared to the gazing condition. R-MSS EMG activity was affected significantly by the difference between these conditions and decreased by 5.2% MVC in the sidelong glancing condition compared to the gazing condition. In association with the change in requirement for head movement between those conditions, EMG balance between the bilateral SCMs changed substantially. Finally, marked muscle activity during ThrMov was found in the MSS that was not directly involved in performing this movement, indicating a form of 'remote facilitation'.

Adult↗
PubMed2006

Retrospective study of 30 cases of Legionella pneumonia in the Kansai region.

Thirty Legionella pneumonia cases were clinically investigated retrospectively from 1999 to 2005 at the Respiratory Medicine Department of Kyoto University and affiliated hospitals. Twenty-eight cases were sporadic and two cases were part of an outbreak. The patients consisted of 28 men and 2 women, with a mean age of 58.8 years (range 25-87). Nineteen cases were smokers and 19 had some underlying disease. The mean period from the disease occurrence to presenting at a hospital was 4.8 days (range 1-15). The mean period from presenting at hospital to Legionella pneumonia diagnosis was 4.6 days (range 0-22). Urinary antigen detection tests for Legionella pneumophilla were performed for 25 cases, and resulted in the diagnosis of 22 cases. Other diagnostic tests with positive findings were culture (buffered charcoal-yeast extract agar, BCYE), the polymerase chain reaction (PCR) test, and serological diagnosis (enzyme immunoassay and microagglutination test). Legionella species diagnosis was obtained by culture and serology for 13 cases: 10 cases had Legionella pneumophila serogroup 1, 2 cases had Legionella pneumophila serogroup 6, and 1 case had Legionella longbeachea. Fluoloquinolones (Fq) are most often used for therapy, especially in recent cases, and were predominantly the chosen treatment (70%). Death due to Legionella pneumonia occurred in 4 cases: 3 cases had severe underlying diseases, and 1 case took 18 days to diagnose (doctors' delay). To detect the majority of Legionella pneumonia cases, a combination of diagnostic examinations is still needed. Regarding the management of community-acquired pneumonia, both the cost and the indication of diagnostic examinations for Legionella infection should be considered simultaneously.

Adult↗
PubMed2006

In-cell NMR spectroscopy of proteins inside Xenopus laevis oocytes.

In-cell NMR is an application of solution NMR that enables the investigation of protein conformations inside living cells. We have measured in-cell NMR spectra in oocytes from the African clawed frog Xenopus laevis. (15)N-labeled ubiquitin, its derivatives and calmodulin were injected into Xenopus oocytes and two-dimensional (1)H-(15)N correlation spectra of the proteins were obtained. While the spectrum of wild-type ubiquitin in oocytes had rather fewer cross-peaks compared to its in vitro spectrum, ubiquitin derivatives that are presumably unable to bind to ubiquitin-interacting proteins gave a markedly larger number of cross-peaks. This observation suggests that protein-protein interactions between ubiquitin and ubiquitin-interacting proteins may cause NMR signal broadening, and hence spoil the quality of the in-cell HSQC spectra. In addition, we observed the maturation of ubiquitin precursor derivative in living oocytes using the in-cell NMR technique. This process was partly inhibited by pre-addition of ubiquitin aldehyde, a specific inhibitor for ubiquitin C-terminal hydrolase (UCH). Our work demonstrates the potential usefulness of in-cell NMR with Xenopus oocytes for the investigation of protein conformations and functions under intracellular environmental conditions.

Animals↗
PubMed2006

Improved clinical outcome of patients with Candida bloodstream infections through direct consultation by infectious diseases physicians in a Japanese university hospital.

OBJECTIVE: To examine whether intervention by infectious diseases physicians (IDPs) in the treatment decisions that emphasize adequate antifungal treatment and early removal of central venous catheter for patients with Candida bloodstream infection (BSI) improves prognosis. DESIGN: Retrospective cohort study of patients with Candida BSI, comparing the prognosis of patients before and after the start of the intervention. SETTING: A 1,240-bed, tertiary care university hospital. PATIENTS: Forty patients with Candida BSI during a 2-year period, from January 2001 to December 2002, were included in the study. Twenty-three patients in the first year after the start of intervention by IDPs (intervention group) were compared with 17 patients in the first year before the start of the IDP intervention (baseline group). INTERVENTIONS: In January 2002, a total of 5 IDPs at Kyoto University Hospital gave unsolicited recommendations on antifungal treatment and advised all physicians treating inpatients who had Candida BSI to remove the central venous catheter. RESULTS: No significant difference was seen between the 2 groups in patients' clinical background, species, and fluconazole susceptibility of the causative organisms. The 30-day survival rate was significantly better in the intervention group (18 [78%] of 23 patients) than in the baseline group (7 [44%] of 16 patients; P=.04 by Fisher's exact test). More patients in the intervention group than in the baseline group received appropriate antifungal therapy (81% vs 50%) and had their central venous catheter removed at an appropriate time (95% vs 81%). CONCLUSION: The introduction of an active system of IDP consultation for every case of Candida BSI in our hospital substantially improved patient outcomes.

Adult↗
PubMed2006

Heteronuclear multidimensional NMR and homology modelling studies of the C-terminal nucleotide-binding domain of the human mitochondrial ABC transporter ABCB6.

Human ATP-binding cassette, sub-family B, member 6 (ABCB6) is a mitochondrial ABC transporter, and presumably contributes to iron homeostasis. Aimed at understanding the structural basis for the conformational changes accompanying the substrate-transportation cycle, we have studied the C-terminal nucleotide-binding domain of ABCB6 (ABCB6-C) in both the nucleotide-free and ADP-bound states by heteronuclear multidimensional NMR and homology modelling. A non-linear sampling scheme was utilised for indirectly acquired 13C and 15N dimensions of all 3D triple-resonance NMR experiments, in order to overcome the instability and the low solubility of ABCB6-C. The backbone resonances for approximately 25% of non-proline residues, which are mostly distributed around the functionally important loops and in the Helical domain, were not observed for nucleotide-free form of ABCB6-C. From the pH, temperature and magnetic field strength dependencies of the resonance intensities, we concluded that this incompleteness in the assignments is mainly due to the exchange between multiple conformations at an intermediate rate on the NMR timescale. These localised conformational dynamics remained in ADP-bound ABCB6-C except for the loops responsible for adenine base and alpha/beta-phosphate binding. These results revealed that the localised dynamic cooperativity, which was recently proposed for a prokaryotic ABC MJ1267, also exists in a higher eukaryotic ABC, and is presumably shared by all members of the ABC family. Since the Helical domain is the putative interface to the transmembrane domain, this cooperativity may explain the coupled functions between domains in the substrate-transportation cycle.

ATP-Binding Cassette Transporters↗
PubMed2006

Identification of the RecR Toprim domain as the binding site for both RecF and RecO. A role of RecR in RecFOR assembly at double-stranded DNA-single-stranded DNA junctions.

The RecR protein forms complexes with RecF or RecO that direct the specific loading of RecA onto gapped DNA. However, the binding sites of RecF and RecO on RecR have yet to be identified. In this study, a Thermus thermophilus RecR dimer model was constructed by NMR analysis and homology modeling. NMR titration analysis suggested that the hairpin region of the helix-hairpin-helix motif in the cavity of the RecR dimer is a binding site for double-stranded DNA (dsDNA) and that the acidic cluster region of the Toprim domain is a RecO binding site. Mutations of Glu-84, Asp-88, and Glu-144 residues comprising that acidic cluster were generated. The E144A and E84A mutations decreased the binding affinity for RecO, but the D88A did not. Interestingly, the binding ability to RecF was abolished by E144A, suggesting that the region surrounding the RecR Glu-144 residue could be a binding site not only for RecO but also for RecF. Furthermore, RecR and RecF formed a 4:2 heterohexamer in solution that was unaffected by adding RecO, indicating a preference by RecR for RecF over RecO. The RecFR complex is considered to be involved in the recognition of the dsDNA-ssDNA junction, whereas RecO binds single-stranded DNA (ssDNA) and ssDNA-binding protein. Thus, the RecR Toprim domain may contribute to the RecO interaction with RecFR complexes at the dsDNA-ssDNA junction site during recombinational DNA repair mediated by the RecFOR.

Bacterial Proteins↗
PubMed2006

Prognosis of cough variant asthma: a retrospective analysis.

Patients with cough variant asthma, a common cause of chronic cough, may develop wheezing. We examined the determinants of this phenomenon and achievement of remission in 42 patients. During 4 years after diagnosis, wheezing developed in 13 of the patients. Early inhaled corticosteroid treatment was inhibitory against the development of wheezing by univariate analysis and by multivariate analysis with an odds ratio of 0.12 (95% confidence interval, 0.02 to 0.87, p = 0.037). Remission was achieved in 7 patients, who were younger than those without remission by univariate analysis (p = 0.048). Early treatment with inhaled corticosteroid may prevent the progression of cough variant asthma to classic asthma.

Adult↗
PubMed2005

Solution structure of the C-terminal transcriptional activator domain of FixJ from Sinorhizobium meliloti and its recognition of the fixK promoter.

FixJ is a response regulator of the two-component signal transduction pathway involved in the transcriptional activation of nitrogen fixation genes of Sinorhizobium meliloti. Upon phosphorylation, FixJ transcriptionally activates the fixK and nifA promoters. We identified a FixJ recognition sequence of 16 bp in the high affinity binding site of the fixK promoter by means of a gel shift assay. In addition, the solution structure of the truncated C-terminal DNA binding domain of FixJ (FixJC) was solved by NMR spectroscopy. FixJC contains five alpha-helices that encode a typical helix-turn-helix motif as a potential DNA binding core with the highest structural similarity toward the C-terminal DNA binding domain of NarL. The addition of the DNA fragment containing the recognition sequence of the high affinity FixJ binding site resulted in intermediate to slow exchange interactions on the NMR time scale in the spectrum of FixJC, while the exchange was rapid in the case of control DNA. These spectral data suggest that more than one molecule of FixJC binds to the recognition sequence, although FixJC alone is present in monomeric form in solution. This result is consistent with a scenario in which a transcriptionally active species of FixJ is a homodimer of the phosphorylated form.

Amino Acid Sequence↗
PubMed2005

Seeligeriolysin O, a protein toxin of Listeria seeligeri, stimulates macrophage cytokine production via Toll-like receptors in a profile different from that induced by other bacterial ligands.

Seeligeriolysin O (LSO), a member of cholesterol-dependent cytolysins of Listeria seeligeri, exhibits cytokine-inducing activity. In this study, we examined the profile of cytokines expressed in macrophages of mice after stimulation with full-length form of recombinant LSO (rLSO530), C-terminal-truncated protein (rLSO483) and two authentic cytokine-inducing Toll-like receptor (TLR) ligands from bacteria, peptidoglycan (PGN) and LPS. Both rLSO530 and rLSO483 were able to induce IL-12 p40 and IL-12 p70 more strongly in macrophages than PGN or LPS. In contrast, IFN-beta and nitric oxide were induced by LPS but not by rLSO530, rLSO483 or PGN. In the presence of exogenously added IFN-beta, IL-12 p40 and IL-12 p70 production was inhibited after LSO stimulation, but IL-12 p70 production was enhanced after PGN stimulation. Although LSO signaling appeared to be associated with both TLR2 and TLR4, the profile of cytokine production by LSO stimulation was distinct from those by stimulation with PGN or LPS. Thus, it was shown that LSO is a unique bacterial ligand that induces macrophage cytokine production in a manner different from PGN or LPS.

Animals↗
PubMed2005

Design of lambda Cro fold: solution structure of a monomeric variant of the de novo protein.

One of the classical DNA-binding proteins, bacteriophage lambda Cro, forms a homodimer with a unique fold of alpha-helices and beta-sheets. We have computationally designed an artificial sequence of 60 amino acid residues to stabilize the backbone tertiary structure of the lambda Cro dimer by simulated annealing using knowledge-based structure-sequence compatibility functions. The designed amino acid sequence has 25% identity with that of natural lambda Cro and preserves Phe58, which is important for formation of the stably folded structure of lambda Cro. The designed dimer protein and its monomeric variant, which was redesigned by the insertion of a beta-hairpin sequence at the C-terminal region to prevent dimerization, were synthesized and biochemically characterized to be well folded. The designed protein was monomeric under a wide range of protein concentrations and its solution structure was determined by NMR spectroscopy. The solved structure is similar to that of a monomeric variant of natural lambda Cro with a root-mean-square deviation of the polypeptide backbones at 2.1A and has a well-packed protein core. Thus, our knowledge-based functions provide approximate but essential relationships between amino acid sequences and protein structures, and are useful for finding novel sequences that are foldable into a given target structure.

Amino Acid Sequence↗
PubMed2005

[Aortic dissection induced by symmetry aortic connector system].

A 74-year-old male with severe triple vessel disease underwent off-pump coronary artery bypass grafting (OPCAB). Preoperative computed tomography (CT) showed severely calcified ascending aorta. We revasculize the left coronary arteries with in situ internal thoracic artery (ITA) graft and the right coronary artery with a saphenous vein graft, which was attached to the disease-free portion of the aortic root, using Symmetry aortic connector system (ACS). Although the operation was uncomplicated, and postoperative course was uneventful until the 5th postoperative day when acute type A aortic dissection occurred. The patient died of aortic rupture on the 7th postoperative day. Necropsy disclosed that the entry located just on the proximal anastomotic site of the vein graft. It is possible placement of ACS device would trigger the dissecting process. With regard to the use of these one-shot devices for diseased aorta, its safety needs further investigation, even though it might be placed on an apparently intact portion.

Aged↗
PubMed2004

Childhood neglect is associated with reduced corpus callosum area.

BACKGROUND: Childhood abuse has been associated with abnormalities in brain development, particularly corpus callosum (CC) morphology. The impact of neglect has not been assessed, though it is the most prevalent form of childhood maltreatment. METHODS: Regional CC area was measured from magnetic resonance imaging scans in 26 boys and 25 girls admitted for psychiatric evaluation (28 with abuse or neglect) and compared with CC area in 115 healthy control subjects. Data were analyzed by multivariate analysis of covariance, with age and midsagittal area as covariates. RESULTS: Total CC area of the abused/neglected patients was 17% smaller than in control subjects (p =.0001) and 11% smaller than in psychiatric patients who had not been abused or neglected (contrast group; p =.01). Control subjects and the contrast group did not differ in total CC area. Neglect was the strongest experiential factor and was associated with a 15%-18% reduction in CC regions 3, 4, 5, and 7 (all p <.02). In contrast, sexual abuse seemed to be the strongest factor associated with reduced CC size in girls. CONCLUSIONS: These data are consistent with animal research that demonstrated reduced CC size in nursery-reared compared with semi-naturally reared primates. Early experience might also affect the development of the human CC.

Adolescent↗
PubMed2004

Myristoylation-regulated direct interaction between calcium-bound calmodulin and N-terminal region of pp60v-src.

pp60v-src tyrosine protein kinase was suggested to interact with Ca2+-bound calmodulin (Ca2+/CaM) through the N-terminal region based on its structural similarities to CAP-23/NAP-22, a myristoylated neuron-specific protein, whose myristoyl group is essential for interaction with Ca2+/CaM; (1) the N terminus of pp60v-src is myristoylated like CAP-23/NAP-22; (2) both lysine residues are required for the myristoylation-dependent interaction and serine residues that are thought to regulate the interaction through the phosphorylations located in the N-terminal region of pp60v-src. To verify this possibility, we investigated the direct interaction between pp60v-src and Ca2+/CaM using a myristoylated peptide corresponding to the N-terminal region of pp60v-src. The binding assay indicated that only the myristoylated peptide binds to Ca2+/CaM, and the non-myristoylated peptide is not able to bind to Ca2+/CaM. Analyses of the binding kinetics revealed two independent reactions with the dissociation constants (KD) of 2.07 x 10(-9)M (KD1) and 3.93 x 10(-6)M (KD2), respectively. Two serine residues near the myristoyl moiety of the peptide (Ser2, Ser11) were phosphorylated by protein kinase C in vitro, and the phosphorylation drastically reduced the interaction. NMR experiments indicated that two molecules of the myristoylated peptide were bound around the hydrophobic clefts of a Ca2+/CaM molecule. The small-angle X-ray scattering analyses showed that the size of the peptide-Ca2+/CaM complex is 2-3A smaller than that of the known Ca2+/CaM-target molecule complexes. These results demonstrate clearly the direct interaction between pp60v-src and Ca2+/CaM in a novel manner different from that of known Ca2+/CaM, the target molecules, interactions.

Binding Sites↗
PubMed2004

Masticatory performance in 80-year-old individuals.

OBJECTIVE: To evaluate the masticatory performance of elderly people at the age of 80 years. SUBJECTS: A total of 283 individuals of 80 years of age took part in a general and dental health survey. MAIN OUTCOME MEASURES: A dental examination including the number of remaining teeth, occlusion, prostheses, bite force recording, and a questionnaire regarding masticatory performance were recorded. SETTING: Five municipalities (Okazaki city, Tokoname city, Tahara town, Atsumi town and Minami-chita town) in Aichi prefecture, Japan. RESULTS: There were 20 or more teeth in 7.4% subjects, and 44.5% were edentulous. Subjects with no occlusion accounted for 77.4% of the total. Subjects with prostheses accounted for 90.8%. Maximum bite force and masticatory ability score for patients with 20 or more teeth or not wearing prostheses were higher than other groups. The non-wearing prostheses group had a low masticatory ability score. CONCLUSION: Most of the 80-year-old individuals recovered their masticatory ability with the assistance of prostheses. Several individuals with 20 or more remaining teeth or without removable dentures present in both jaws had a high score for bite forces and masticatory abilities.

Aged↗