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Biomedical subjects

K Nishimura

Publications and source records attributed to K Nishimura.

At least 163 records · Page 9Linked to original sources

Physical model-based indirect measurements of blood pressure and flow using a centrifugal pump.

This article describes a technique offering indirect measurements of pump pressure differential and flow with certain accuracy independent of changes in blood viscosity. This technique is based on noninvasive measurements of the motor current and rotation speed using the physical model equations of the centrifugal pump system. Blood viscosity included in the coefficients of the dynamic equations is first estimated, and then substitution of the estimated viscosity into the steady equations of the model provides pump flow and pressure differential. In vitro tests using a Capiox pump showed a sufficient linear correlation between actual values and their estimates for pressure differential and pump flow. An in vivo test using a 45 kg sheep showed that the proposed algorithm needs robustness for the convergence of estimates of viscosity. An overall evaluation, however, of the developed algorithm/model showed indications of success in terms of efficient computation and modeling.

Algorithms↗

Stages of disease severity and factors that affect the health status of patients with chronic obstructive pulmonary disease.

BACKGROUND: We hypothesized that the factors which may influence health status would differ in patients at different disease stages of chronic obstructive pulmonary disease (COPD). The present study investigated how impairments in health status were distributed in male patients at each disease stage according to the British Thoracic Society (BTS) guidelines, and analysed the contribution of the clinical indices, the dyspnoea rating and the psychological status to the health status of patients at the three disease stages of COPD. METHODS: A total of 218 consecutive male patients with stable COPD were recruited from our outpatient clinic. All eligible patients completed pulmonary function testing, progressive cycle ergometry, a dyspnoea rating [Medical Research Council (MRC) dyspnoea scale], an assessment of their anxiety and depression [Hospital Anxiety and Depression Scale (HADS)], and an assessment of their health status [the St. George's Respiratory Questionnaire (SGRQ)]. The patients were categorized into three groups: mild COPD with a FEV1 at 60-79% of the predicted value, moderate COPD at 40-59% of the predicted value, and severe COPD at below 40% of the predicted value. RESULTS: Twenty-five patients (11%) had mild COPD, 72 patients (33%) had moderate COPD, and 121 patients (56%) had severe COPD. Significant differences were observed for the total score and for three components on the SGRQ among patients at the three stages (one-way ANOVA, P<0.05). The scores for the total SGRQ and for the activity component were significantly higher for patients with severe COPD than for patients with moderate COPD [Fisher's least-significant-difference (LSD) method, P<0.05], and also significantly higher for moderate COPD patients than for mild COPD patients. The maximal oxygen uptake (VO2 max) correlated significantly with the total SGRQ score in the mild patients [Pearson's correlation coefficient (r) = -0.67], but not in the moderate or severe patients. The MRC dyspnoea scale had strong correlations with the SGRQ in all patient groups (r = 0.53 to approximately 0.70). Anxiety and depression on the HADS showed moderate correlations with the SGRQ score in the mild and severe patients (r = 0.51 to approximately 0.57). Multiple regression analysis showed that in patients with mild COPD, the MRC and VO2 max accounted for the total score on the SGRQ. Anxiety on the HADS plus the MRC scale accounted for the total score on the SGRQ in patients with moderate COPD, and anxiety on the HADS, the MRC scale and the FEV1 significantly influenced the SGRQ severe COPD patients. CONCLUSIONS: The disease staging proposed by the BTS guidelines can separate patients with COPD according to impairments in their health status. Furthermore, the factors that influence health status differed in patients at the three disease stages. Our findings support the boundaries used in disease staging and some recommendations from the BTS guidelines.

Aged↗

The effectiveness of the visual analogue scale 8 in measuring health-related quality of life for COPD patients.

The Visual Analogue Scale 8 (VAS8), consisting of eight linear scales, has been developed to measure health-related quality of life (HRQoL) in chronic obstructive pulmonary disease (COPD) patients. The purpose of this study was to examine the validity and responsiveness of the VAS8. First, HRQoL was assessed in a cross-sectional study with the VAS8 and the St George's Respiratory Questionnaire (SGRQ) in 46 COPD patients. Relationships between the VAS8 and various physiological parameters were examined. Second, in a longitudinal study, changes in HRQoL scores after pulmonary rehabilitation were evaluated in 29 COPD patients. The total VAS8 scores showed a weak correlation with vital capacity and maximal inspiratory pressure and a moderately strong correlation with 6-min walking distance and dyspnoea rating. The total VAS8 score showed a significant correlation with each SGRQ score. Furthermore, almost every VAS8 and SGRQ score improved significantly after pulmonary rehabilitation. The change in the total VAS8 value showed a strong correlation with that of the SGRQ. The VAS8 is well-suited to assess HRQoL in COPD patients. Visual analogue scales are generally useful in measuring HRQoL in COPD patients, and the VAS8 is particularly beneficial because of its ease of use.

Aged↗

Effect of inhaled indomethacin in asthmatic patients taking high doses of inhaled corticosteroids.

BACKGROUND: Cyclooxygenase products of arachidonic acid may play a part in bronchoconstriction and airway inflammation in asthma. OBJECTIVE: We sought to determine the effect of inhaled indomethacin on asthma control and asthma exacerbations during reduction of inhaled corticosteroids in patients with moderate-to-severe steroid-dependent asthma. METHODS: We conducted a double-blind, randomized, parallel-group, multicenter study in 38 patients with asthma taking high doses (> or =1500 microg/d) of beclomethasone dipropionate (BDP). After a run-in period, patients were assigned inhaled indomethacin (50 mg/d) or placebo for 6 weeks, during which the daily doses of BDP were reduced to half at week 2 and then to one third of the baseline dose at week 4. RESULTS: Data were available from 34 patients. After the reduction of BDP doses, FEV(1), peak expiratory flow, asthma symptoms, and exhaled nitric oxide concentrations deteriorated in both treatment groups, but these effects were less pronounced in the indomethacin group compared with the placebo group. During the 6-week treatment period, 89% of the patients receiving placebo had relapse of asthma, whereas only 38% of those receiving inhaled indomethacin did so (P =.003). CONCLUSION: Inhalation of indomethacin can reduce asthma exacerbations induced by reduction of high-dose inhaled corticosteroid in steroid-dependent asthma.

Administration, Inhalation↗

Percutaneous balloon fenestration in a case of traumatic abdominal aortic dissection with lower extremity ischemia.

A 38-year-old man was involved in a traffic accident and experienced a heavy blow to the abdomen. He had traumatic abdominal aortic dissection with right lower extremity ischemia. He underwent percutaneous balloon fenestration, which is safe and minimally invasive, for relief of right lower extremity ischemia. He has been working for 2 years without any signs of vascular compromise. Percutaneous balloon fenestration is one of the few treatments for traumatic abdominal aortic dissection.

Abdominal Injuries↗

A new PCR primer for the identification of Paracoccidioides brasiliensis based on rRNA sequences coding the internal transcribed spacers (ITS) and 5 x 8S regions.

Internal transcribed spacer (ITS) genes including the 5.8S ribosomal (r)RNA of Paracoccidioides brasiliensis were amplified and the DNA sequences were determined. Based on a comparison of the sequence information, a new polymerase chain reaction (PCR) primer pair was designed for specific amplification of DNA for P. brasiliensis. This primer pair amplified a 418-bp DNA sequence and was 100% successful in identifying 29 strains of P. brasiliensis (including the reference strains) isolated from the regions of Brazil, Costa Rica, Japan, Argentina or from different sources. The results of specificity tests of these primers to compare the fungus with those of Aspergillus fumigatus, Blastomyces dermatitidis, Candida albicans, Cryptococcus neoformans, Histoplasma capsulatum and Penicillium marneffei are also reported.

DNA Primers↗

Effect of pH, carbon source and K+ on the Na+-inhibited germ tube formation of Candida albicans.

The effect of pH, carbon source and K+ on the Na+ -inhibited germ tube formation of the pathogenic fungus Candida albicans was examined in the arginine-phosphate modified (APM) medium. All C. albicans cells formed germ tubes in APM medium at pH 5.0-9.0. Na+ inhibited germ tube formation in a concentration dependent manner ranging from 0.2 to 1.0 M, and was further influenced by the pH of the medium. The inhibitory effect of Na+ was lowest at pH 8.0, and germ tube formation ceased at 1.0 M Na+ for any pH (4.0-9.0). At pH > or = 6.0, non-germ tube-forming cells did not show yeast growth; whereas at pH < or = 5.0, Na+ inhibited only germ tube formation but did not inhibit yeast growth. The inhibitory effect of Na+ was stronger in glucose medium than in galactose medium as carbon source. K+, at 0-0.8 M, had almost no effect on germ tube formation. However, in the presence of Na+, a very low concentration of K+ (0.5 mM) was able to release the cells from Na+ arrest and produced an increase in the rate as well as the percentage of germ tube formation. Intracellular Na+/K+ ratios increased with the increase in extracellular Na+ concentration, whereas the ratios decreased and remained within nontoxic levels when the extracellular K+ concentration was increased.

Candida albicans↗

The skin permeation mechanism of ketotifen: evaluation of permeation pathways and barrier components in the stratum corneum.

To evaluate the pathways and barrier components in the stratum corneum (SC) for the permeation of ketotifen, the effect of delipidization on the permeation and partition was examined under several donor pHs. Assuming that ionized ketotifen (KTH+) and un-ionized ketotifen (KT) contribute independently in both permeation and partition, the intrinsic permeability coefficients and SC/water partition coefficients of both species were estimated. Delipidization enlarged the permeability of KTH+ 100 times. This suggested that the lipid phase functions as the barrier against KTH+. KT has an intrinsic permeability 100 times larger than that of KTH+. Delipidization did not result in a significant change in permeability of KT. This suggested that the permeability of KT through the lipid phase is comparable to that through the aqueous phase in delipidized SC; that is, the lipid phase functions as a highly permeable pathway for KT. On the other hand, the permeability coefficient of KT through delipidized SC was 1/34 of that through the pure aqueous layer, which had a thickness equivalent to SC. Since this suggests that the permeability of KT through the proteinaceous phase is much lower than that through the aqueous phase, the proteinaceous phase can be assumed to function as a barrier against the permeation of KT. From these results, it is concluded that the predominant permeation pathway for KT is through the lipid phase. The SC/water partition coefficient of KT was cut in half by delipidization, but the value was still more than 100. These results show that the proteinaceous phase functions not only as the barrier, but also as the depot for KT. The knowledge obtained here will be useful for formulation design and for the selection of enhancers in a transdermal therapeutic system of ketotifen.

Algorithms↗

Impairment of airway mucociliary transport in patients with sinobronchial syndrome: role of nitric oxide.

Nitric oxide (NO) produced within the respiratory tract can stimulate ciliary motility of airway epithelial cells and hence mucociliary transport. In this study, to determine the role of NO in mucociliary dysfunction in sinobronchial syndrome (SBS), we measured NO concentrations in the exhaled air by chemiluminescence analyzer and nasal clearance time (NCT) by saccharin test. Exhaled NO concentrations in patients with SBS were 39% of those in healthy nonsmokers and 55% of those in healthy smokers. The patients also showed prolonged NCT compared with healthy subjects, and there was a significant negative correlation between exhaled NO concentrations and NCT. Furthermore, concentrations of chloride (Cl) in the sputum supernatant were higher in SBS patients than in healthy subjects, and there was a significant negative correlation between sputum Cl concentrations and exhaled NO concentrations. These results suggest that airway mucociliary clearance is impaired in patients with SBS and that this impairment might result from the reduced production of NO and the impaired availability of the molecule in the mucociliary apparatus.

Adult↗

Clinical course and prognosis of patients with chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a basically benign disease, but the prognosis is so poor that the mortality rate is similar to some malignant diseases. Depending on the disease severity, the 5-year mortality rate of patients with COPD varies from 40 to 70%. The three major causes of death have been identified as COPD itself, lung cancer, and cardiovascular disease. The following factors have been reported to be related to survival: FEV1 (especially the maximal attainable lung function), age, gender, PaO2, PaCO2, body weight, and comorbidity. There have been several large-scale randomized clinical trials to examine the prophylactic effects of inhaled anti-cholinergics and inhaled corticosteroids on the annual decline in FEV1. However, unfortunately, in all of the published studies, these drugs had no effect on the annual decline in FEV1.

Cause of Death↗

Crystallization and preliminary X-ray analysis of endopolygalacturonase SE1 from Trichosporon penicillatum.

Endopolygalacturonase SE1 from Trichosporon penicillatum has been crystallized by the hanging-drop method of vapour diffusion using ammonium sulfate as a precipitant. The crystals belong to the hexagonal space group P6(1) or P6(5), with unit-cell parameters a = b = 135.0, c = 70.7 A, gamma = 120 degrees. The calculated V(M) based on one molecule per asymmetric unit is 3.09 A(3) Da(-1). A native data set from a crystal has been collected to 2.0 A resolution on a Cu Kalpha rotating-anode X-ray source.

Crystallography, X-Ray↗

Preferential activity of wild-type and mutant tumor necrosis factor-alpha against tumor-derived endothelial-like cells.

Tumor-derived endothelial-like cells (tEC) were prepared by culturing human umbilical vein endothelial cells (HUVEC) in the presence of HT1080 human fibrosarcoma-conditioned medium. tEC showed higher permeability and less cell-adhesion activity than normal HUVEC (nEC). Tumor necrosis factor-alpha (TNF) is known to have tumor-vasculature disrupting activity. tEC showed higher cytotoxicity to recombinant human TNF (rhTNF) than nEC, and was not observed using HUVEC cultured with WI38 human diploid cell-conditioned medium as a medium-control. These results demonstrate that tEC acquire physiological properties of tumor-associated vasculature, and may be a useful model system for the study of the mechanisms of TNF antitumor action. The TNF-mutant RGD-V29 (code No. F4614), which has an inserted 4Arg-Gly-Asp sequence and an 29Arg-->Val replacement, was found to induce greater preferential destruction of tEC compared to rhTNF. When the preferential activities were evaluated in terms of 30% cytotoxicity (IC30) ratio (nEC/tEC), the ratio was 460 for RGD-V29 compared to 4.2 for rhTNF. RGD-V29 also exhibited cell-adhesive function and bound preferentially to the p55 TNF-receptor. Both these properties of RGD-V29 contributed to the tEC selective cytotoxicity, indicating that the RGD ligands and selective p55 receptor binding on the cells, although uncharacterized, are involved in tEC targeting. Therefore, the TNF mutant RGD-V29 may show greater selectivity toward tumor vasculature than wild-type TNF.

Binding, Competitive↗

Effect of hepatocyte growth factor on sperm motility.

PROBLEM: Hepatocyte growth factor (HGF) exists abundantly in seminal plasma and its receptor, c-met, is expressed on spermatozoa. Considering its motogenic activity, we speculated that HGF might affect the movement ability of spermatozoa. METHODS: Recombinant HGF was added to washed spermatozoa and their movements were analyzed using a computer-assisted sperm analyzer. The concentration of HGF in the seminal plasma of infertile patients (n = 83) was measured by ELISA, and the data were compared with their hormonal profile and semen parameters. RESULTS: The HGF physiological concentration (1 ng/mL) maintained the motility of sperm after a long incubation, though the difference was not statistically significant. Recombinant HGF did not affect the linearity or frequency of movement, which suggested that it does not evoke the hyperactivation of spermatozoa. The concentration of HGF in seminal plasma did not correlate with any clinical parameter of the patients. CONCLUSIONS: These findings contradict the theory that HGF controls the movement of sperm. The main role of this axis in the male reproductive system might be maturation in the epididymis.

Hepatocyte Growth Factor↗

Identification and phylogenetic relationship of the most common pathogenic Candida species inferred from mitochondrial cytochrome b gene sequences.

We sequenced a 396-bp region of the mitochondrial cytochrome b gene of the most common clinically important Candida species: Candida albicans, C. glabrata, C. parapsilosis, C. tropicalis, C. krusei, and C. lusitaniae. The recently described species of Candida, C. dubliniensis, associated with mucosal candidiasis in human immunodeficiency virus-infected individuals, was also included. Two to five strains of each species were examined. Some species represented intraspecies variation, which was not more than 1.8% (DNA). However, interspecies variations were more than 10 and 7%, respectively, for DNA and amino acid sequences. Multiple alignments of nucleotide and deduced amino acid sequences revealed species-specific nucleotides and amino acids. Nucleotide- and amino acid-based phylogenetic trees were constructed and are discussed. Using the database, it is possible to identify presumptive Candida species within a working day.

Amino Acid Sequence↗

Mitochondrial cytochrome b gene analysis of Aspergillus fumigatus and related species.

Nucleotide sequences of 426 bp from the mitochondrial (mt) cytochrome b genes of six anamorph species and two species of Neosartorya teleomophs of Aspergillus section Fumigati were determined. These sequences were used to build nucleotide- and amino acid-based trees for phylogenetic analysis. Thirteen strains of A. fumigatus including 10 clinical isolates of A. fumigatus, 1 type culture of A. fumigatus var. fumigatus, 1 type culture of A. fumigatus var. ellipticus, and 1 strain of A. fumigatus var. albus, had the same nucleotide sequences. One strain of A. fumisynnematus, two strains labeled A. neoellipticus, two strains of A. viridinutans, and one strain of A. duricaulis had distinct nucleotide and amino acid sequences. Two strains of A. brevipes were divided into two types. One produced a 1,500-bp fragment that included an intron. The nucleotide sequences of its two exons were similar to those of the A. fumigatus, and the derived amino acid sequence was the same as that for A. fumigatus. The other produced a 426-bp fragment and had the same nucleotide and amino acid sequences as A. unilateralis. Neosartorya fischeri var. fischeri and N. stramenia had nucleotide sequences that differed from that of A. fumigatus. These species possessed their own characteristic nucleotide sequences that differed from each other. In comparisons of homologous sequences from four other pathogenic species of Aspergillus, regions specific to section Fumigati were found. The mt cytochrome b gene analysis was valuable for the identification, classification, and phylogenetic analysis of isolates of section Fumigati.

Amino Acid Sequence↗