Biomedical subjects

M Shigeta

Publications and source records attributed to M Shigeta.

132 records · Page 8Linked to original sources

PubMedDate not supplied

Global dimensional complexity of multichannel EEG in mild Alzheimer's disease and age-matched cohorts.

Multichannel EEG as sequence of momentary brain field maps constitutes a trajectory through K-dimensional state space (K = number of channels); the complexity of this trajectory is assessed by the nonlinear measure of global correlation dimension (Global Dimensional Complexity, GDC) with the number of electrodes as embedding dimension. We analyzed eyes-closed EEG of three age-matched subject groups: mild Alzheimer's disease (AD; n = 21), mild cognitive impairment (29) and subjective memory complaint (29). Kruskal-Wallis statistics showed an overall effect between groups. AD patients differed significantly (GDC = 4.56) from mild cognitive impairments (GDC = 4.98) and from subjective memory complaints (GDC = 4.93). GDC also had significant positive correlations with mental condition and performance (MMSE and WAIS-R scores). Thus, the dynamics of brain state development over time in mild AD differs from that in mild cognitive impairment and in subjective memory complaint cases.

Aged↗

PubMedDate not supplied

Quantitative electroencephalography power and coherence in Alzheimer's disease and mild cognitive impairment.

In this study the best combination of quantitative electroencephalographic variables (qEEG) for the discrimination of groups with mild to moderate Alzheimer's disease (AD), mild cognitive impairment and healthy subjects was defined and related to neuropsychological performance. The study population included 18 patients with mild to moderate probable AD, 19 subjects with objective memory disturbance, 17 subjects with subjective memory complaints who did not have clinical evidence of memory disturbance, and 16 healthy controls. AD patients had significantly increased theta and decreased alpha relative power, mean frequency, and temporoparietal coherence. There was no significant difference in the mean frequency in the left temporal region between AD patients and subjects with objective memory disturbances. Temporoparietal coherence appeared as a discriminant variable together with alpha and theta relative power only between AD patients and controls giving 77.8% sensitivity and 100% specificity. Significant correlations between regional changes in qEEG variables and cognitive functions were found.

Aged↗

PubMedDate not supplied

Effect of the growth rate of Pseudomonas aeruginosa biofilms on the susceptibility to antimicrobial agents.

The growth rate of biofilm cells of a leucine-requiring mutant Pseudomonas aeruginosa HU1 was regulated by the leucine concentration in the chemically defined medium, and the effect of the growth rate of biofilm cells on the antimicrobial activities of the antimicrobial agents piperacillin (PIPC), imipenem (IPM) and ofloxacin (OFLX) were evaluated. PIPC showed little effect on the biofilm bacteria regardless of the leucine concentration in the medium. IPM showed weak bactericidal activity to biofilm cells; activity was greater in younger biofilm cells growing in high concentrations of leucine. On the other hand, OFLX revealed strong bactericidal activity to biofilm bacteria regardless of the growth rate. Our data suggest that the bactericidal action of antimicrobial agents to biofilm bacteria is different from that to planktonic bacteria. The bioassay using mutants with regulated growth is useful for the evaluation of the efficacy of antimicrobial agents against biofilm bacteria.

Anti-Bacterial Agents↗

PubMedDate not supplied

Permeation of antimicrobial agents through Pseudomonas aeruginosa biofilms: a simple method.

In this study, we evaluated the permeation of piperacillin (PIPC), imipenem (IPM), amikacin (AKM), gentamicin (GM), ofloxacin (OFLX), levofloxacin (LVFX), ciprofloxacin (CPFX) and sparfloxacin (SPFX) through Pseudomonas aeruginosa biofilm with a simple new method. Bacteria used were a leucine-requiring mucoid mutant. Bacteria were grown on the membrane of a cell culture insert in chemically defined medium and incubated at 37 degrees C for 5 days. At days 0, 1, 3 and 5, the penetration rates through the biofilms were measured. PIPC and IPM demonstrated relatively high permeation both with penetration rates at day 5 of 50%, whereas AMK and GM, which are aminoglycosides, showed low permeation both with penetration rates after day 1 of less than 25%. Among the 4 fluoroquinolones, LVFX and SPFX demonstrated excellent permeation with penetration rates that reached 100% from day 0 to 5, while OFLX and CPFX showed almost the same permeation as IPM. This method of measuring penetration rates of antimicrobial agents through biofilm is very simple and useful for the evaluation of antibiotics against biofilm-forming bacteria.

Anti-Bacterial Agents↗

PubMedDate not supplied

Application of the quantitative sperm immobilization test for follow-up study of sperm-immobilizing antibody in the sera of sterile women.

For quantitative estimation of sperm immobilizing antibody, a new assay method was developed and applied to a follow-up study of antibody titers in the sera of sterile women. The 50% sperm immobilization units (SI50) estimated by the quantitative method ranged from 1.2 to 97.3 in the sera from 16 sterile women who showed relatively high antibody activities in the previous semiquantitative sperm immobilization test. When the quantitative antibody titers, SI50, were followed over 3 years in sterile women with the sperm immobilizing antibody, the antibody titers were found to be unstable, and undulated over a period of several months. Therapy consisting of use of a condom seemed to be ineffective in decreasing the antibody titers.

Adult↗

PubMedDate not supplied

Ultrafast CT scoring system for assessing bronchopulmonary dysplasia: reproducibility and clinical correlation.

PURPOSE: To evaluate the reproducibility of the Ultrafast CT (UFCT) scoring system and assess its usefulness in monitoring clinical severity in infants with bronchopulmonary dysplasia (BPD). MATERIALS AND METHODS: UFCT scoring was done in 22 infants (15 boys and 7 girls aged 1 to 37 months) with BPD. A total of 258 lung fields were evaluated for the presence of hyperaeration, linear opacities, triangular subpleural opacities, and bronchovascular bundle distortion or thickening, and UFCT scores were given. Intraobserver and interobserver agreement and reproducibility of UFCT scores were statistically analyzed. In 12 patients, UFCT scores were linearly correlated with clinical severity scores based on respiratory dysfunction and complexity of care. RESULTS: "Hyperaeration," which was the most frequent (18 of 22, 81.8%) finding, showed high concordance (kappa = 0.73, p < 0.001, kappa = 0.59, p < 0.001), and its UFCT scores significantly correlated with intraobserver and interobserver analyses (r = 0.94, p < 0.001, r = 0.82, p < 0.001, respectively). UFCT scores for hyperaeration significantly correlated with clinical scores (r = 0.75, p < 0.01), whereas those for the others did not. CONCLUSION: UFCT is useful for assessing BPD. Hyperaeration was the most common and reproducible finding, and its extent significantly correlated with clinical severity.

Bronchopulmonary Dysplasia↗