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Biomedical subjects

K Nishimura

Publications and source records attributed to K Nishimura.

At least 433 records · Page 24Linked to original sources
PubMed1996

Effects of endothelin-1 on optic nerve head blood flow in cats.

We determined the effects of endothelin-1 on optic nerve head (ONH) blood flow in anesthetized cats. Endothelin-1 (50-2500 pmol) injected into the vitreous produced a dose-related and sustained decrease (22 +/- 6% by 500 pmol and 36 +/- 11% by 2500 pmol) in the ONH blood flow. Blood pressure (BP) and heart rate (HR) remained, however, unchanged. In contrast, intravenous (i.v.) injected endothelin-1 (0.004-0.4 nmol kg-1) produced a dose-related and short-lasting increase in the ONH blood flow; its maximum increase by 0.4 nmol kg-1 was 135 +/- 34%. Endothelin-1, at 0.4 nmol kg-1, i.v., produced a transient decrease followed by a more sustained increase in BP, but had no remarkable effect on HR. The increase in ONH blood flow by i.v. injection of endothelin-1 was abolished by N(G)-nitro-L-arginine methyl ester (L-NAME, 5 mg kg-1 min-1, i.v.). The suppression of blood flow by L-NAME was reversed by the addition of L-arginine (50 mg kg-1 min-1). Pressor responses to endothelin-1 (0.4 nmol kg-1, i.v.) were augmented in the presence of L-NAME, but reversed in combination with L-arginine. These findings suggest that i.v. injection of endothelin-1 causes NO release from endothelial cells which increases ONH blood flow, whereas intravitreal injection of endothelin-1 decreases ONH blood flow by its vasoconstrictive effect. Different populations of ET receptors on vascular smooth muscles or endothelial cells would reflect the opposing effects of endothelin-1.

Animals↗
PubMed1996

Bronchial mucoid impaction due to the monokaryotic mycelium of Schizophyllum commune.

We report, to our knowledge, the first case of mucoid impaction of the bronchi due to a hypersensitivity reaction to the monokaryotic mycelium of Schizophyllum commune. The patient was hospitalized because of mild asthma attacks, persistent cough, peripheral eosinophilia, and "gloved finger" shadows on a chest roentgenogram. Bronchoscopic examination disclosed mucoid impactions that consisted of accumulations of eosinophils, Charcot-Leyden crystals, and nondichotomously branched hyphae in B3, B9, and B10 of the left lung. Cultures of the mucous plugs and sputum samples yielded white, felt-like mycelial colonies that were later identified as the monokaryotic mycelium of S. commune by use of mating tests with established monokaryotic and dikaryotic strains of S. commune. The results of tests for serum antibody to S. commune cytosol antigen were positive. Repeated bronchoscopies for performing bronchial toilet were effective in removing the mucous plugs and relieving the patient's symptoms. We suggest that the monokaryotic mycelium of S. commune should be considered as one of the fungi that can cause hypersensitivity-related lung diseases.

Aged↗
PubMed1996

Expression of the puf operon in an aerobic photosynthetic bacterium, Roseobacter denitrificans.

The effects of oxygen and light on the expression of the puf operon were investigated in Roseobacter denitrificans in a comparison with those in Rhodobacter sphaeroides. In darkness, the levels of the total puf mRNA in Ros. denitrificans were about 1.3 times those in Rb. sphaeroides at low concentrations of oxygen, reflecting the accumulation of bacteriochlorophyll and carotenoids. The oxygen tension, up to 94% saturation of dissolved oxygen, did not affect the levels of the total puf transcripts in Ros. denitrificans, whereas those in Rb. sphaeroides were reduced to 55% of the maximum level even at 50% saturation. Four puf-specific transcripts were detected: a 0.5-kb transcript was the most abundant; 1.2-kb and 1.9-kb transcripts accumulated at low levels; and a 3.5-kb transcript accumulated at very low levels under all conditions tested. The levels of the individual transcripts were barely affected by molecular oxygen. An S-1 nuclease protection assay revealed that the 0.5-kb transcript encoded the LHI-alpha and LHI-beta subunits (pufBA), the 1.2-kb transcript encoded puf-BA and part of pufL, and the 1.9-kb transcript encoded pufBAL and part of pufM. It was not clear whether the 3.5-kb transcript encoded the entire pufBALM and the gene for the polypeptide moiety of cytochrome c. The difference in levels between the 0.5-kb transcript and the other transcripts (1.2 kb, 1.9 kb, and 3.5 kb) was presumed to be due to the presence of several stem-loop structures at the 3' terminus of the 0.5-kb transcript which acted as terminators of transcription and, possibly, as protection against nucleolytic digestion. Light inhibited the expression of the puf operon in Ros. denitrificans more effectively than that in Rb. sphaeroides. The insensitivity to oxygen, as well as the sensitivity to light, of the expression of the puf operon in Ros. denitrificans, which was different from that in Rb. sphaeroides, seemed to represent a mode of adaptation that allowed the former cells to avoid photodynamic damage by light under highly aerobic conditions.

Bacteria↗
PubMed1996

A transcription factor with a leucine-zipper motif involved in light-dependent inhibition of expression of the puf operon in the photosynthetic bacterium Rhodobacter sphaeroides.

In the purple nonsulfur photosynthetic bacterium Rhodobacter sphaeroides the synthesis of components of the photosystem is regulated in response to oxygen tension and light intensity. We have purified and cloned a trans-acting protein (SPB) that binds to the promoter region of the puf operon, which encodes the apoproteins of light-harvesting complex I and the reaction center. The SPB was composed of a single polypeptide with an apparent molecular mass of 15.0 kDa. The nucleotide sequence of the spb gene was determined. The gene encoded 104 amino acid residues, which correspond to a molecular mass of 11.5 kDa. SPB exhibited 53% homology to HvrA in Rhodobacter capsulatus. The deduced amino acid sequence indicated that SPB contained a region with homology to the leucine-zipper motif of c-JUN, a transcription factor in eukaryotes, and SPB also had a DNA-binding domain on the amino-terminal side of the leucine-zipper motif. The leucine-zipper motif of SPB might contribute to the formation of a dimer. Northern analysis indicated that spb was constitutively and monocistronically transcribed in R. sphaeroides, irrespective of growth conditions. Structural and functional differences between SPB and HvrA are discussed.

Amino Acid Sequence↗
PubMed1996

Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max.

This study consists of two training experiments using a mechanically braked cycle ergometer. First, the effect of 6 wk of moderate-intensity endurance training (intensity: 70% of maximal oxygen uptake (VO2max), 60 min.d-1, 5 d.wk-1) on the anaerobic capacity (the maximal accumulated oxygen deficit) and VO2max was evaluated. After the training, the anaerobic capacity did not increase significantly (P > 0.10), while VO2max increased from 53 +/- 5 ml.kg-1 min-1 to 58 +/- 3 ml.kg-1.min-1 (P < 0.01) (mean +/- SD). Second, to quantify the effect of high-intensity intermittent training on energy release, seven subjects performed an intermittent training exercise 5 d.wk-1 for 6 wk. The exhaustive intermittent training consisted of seven to eight sets of 20-s exercise at an intensity of about 170% of VO2max with a 10-s rest between each bout. After the training period, VO2max increased by 7 ml.kg-1.min-1, while the anaerobic capacity increased by 28%. In conclusion, this study showed that moderate-intensity aerobic training that improves the maximal aerobic power does not change anaerobic capacity and that adequate high-intensity intermittent training may improve both anaerobic and aerobic energy supplying systems significantly, probably through imposing intensive stimuli on both systems.

Adult↗
PubMed1996

Th2 suppressor cells are more susceptible to sphingosine than Th1 cells in murine contact photosensitivity.

Murine contact photosensitivity (CPS) to 3,3',4',5-tetrachlorosalicylanilide (TCSA) is a cutaneous delayed-type hypersensitivity reaction in which both positive and negative regulatory pathways exist. The latter pathway is mediated by antigen-specific, CD4+ suppressor T cells (CPS-Ts) that are Th2 cells. We examined the effects of sphingosine and synthetic cell-permeable analogs of ceramide on the cellular kinetics of CPS-Ts and immune lymph node cells from TCSA-photosensitized mice (CPS-LNC), along with other murine T-cell populations. The addition of sphingosine at 10 or 3 microM to in vitro cultures suppressed DNA synthesis of CPS-Ts and Th2 clones, including D10 cells and 24-2 cells, but not that of CPS-LNC or Thl clones, including 23-1-8 and 28-4 cells. This suggested that sphingosine exerts its inhibitory effects preferentially on the proliferation of Th2 cells. Although suppressing DNA synthesis, sphingosine augmented the production and mRNA expression of interleukin-4 (IL-4) and enhanced the expression of the IL-4 receptor in CPS-Ts. In addition, the ability of sphingosine to induce signal transduction of CPS-Ts was confirmed by elevation of the intracellular free Ca++ concentration. Because CPS-Ts exposed to sphingosine exhibited a lower G2M/G1 ratio than control, these seemingly ambivalent phenomena may be caused by retardation of the G1 to S phase progression, a cell-cycle dysregulation known to augment cytokine production. In contrast to sphingosine, cell-permeable ceramide did not affect the proliferation of these cells when stimulated with mitogen/antigen and did not augment IL-4 production by CPS-Ts. Our study suggests that sphingosine modifies the Th1/Th2 balance by preferentially affecting the cellular kinetics of Th2.

Allergens↗
PubMed1996

Inhibitors of sphingolipid synthesis modulate interferon (IFN)-gamma-induced intercellular adhesion molecule (ICAM)-1 and human leukocyte antigen (HLA)-DR expression on cultured normal human keratinocytes: possible involvement of ceramide in biologic action of IFN-gamma.

To elucidate the participation of sphingosine and ceramide in the biologic action of cytokines on epidermal keratinocytes, we studied whether inhibitors of sphingolipid synthesis modulate interferon (IFN)-gamma-induced intercellular adhesion molecule (ICAM)-1 and human leukocyte antigen (HLA)-DR expression on cultured normal human keratinocytes. Pretreatment of keratinocytes with L-cycloserine or fumonisin B1, but not 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP), significantly suppressed both ICAM-1 and HLA-DR expression induced by IFN-gamma. Because the synthesis of all kinds of sphingolipids is blocked by L-cycloserine and all except that of sphinganine by fumonisin B1, whereas PDMP inhibits the synthesis of glucosylceramide and glycosphingolipids, the result suggests the participation of ceramide and/or sphingosine in IFN-gamma-induced ICAM-1 and HLA-DR expression. Exogenous C2-ceramide reversed the effects of L-cycloserine and fumonisin B1. On the other hand, sphingosine reversed the effect of L-cycloserine, but not of fumonisin B1. These results indicate that ceramide participates in this pathway, as fumonisin B1, but not L-cycloserine, inhibits the synthesis of ceramide from sphingosine. In addition, reverse transcriptase polymerase chain reaction showed that L-cycloserine reduced the mRNA for ICAM-1, HLA-DR alpha, and HLA-DR beta induced by IFN-gamma, and C2-ceramide and sphingosine antagonized the effect of L-cycloserine. Furthermore, the degradation rate of fluorescent sphingomyelin into ceramide in keratinocytes was increased by IFN-gamma, suggesting that IFN-gamma activates sphingomyelin hydrolysis in keratinocytes. These observations suggest the possible role of ceramide in IFN-gamma-induced ICAM-1 and HLA-DR expression on keratinocytes. Ceramide may function as an endogenous modulator mediating the cytokine signals in keratinocytes.

Base Sequence↗
PubMed1996

Bladder cancer producing granulocyte colony-stimulating factor: a case report.

A rare case of bladder cancer producing granulocyte colony-stimulating factor (G-CSF) is reported. A 63-year-old man with a progressive, grade 3 transitional cell bladder carcinoma, showed marked leukocytosis (maximum 181,800/mm3) and an elevated serum G-CSF to 131.7 pg/mL. After radical cystectomy and neoadjuvant chemotherapy, the tumor recurred locally. Immunohistochemical examination with monoclonal antibody specific for G-CSF revealed positive staining in the local recurrent tumor. To our knowledge, there have been only seven cases reported of bladder cancer producing G-CSF.

Carcinoma, Transitional Cell↗
PubMed1996

A new magnetically suspended centrifugal pump: in vitro and preliminary in vivo assessment.

To overcome problems derived from the shaft within the conventional centrifugal pump, we have been developing a new centrifugal pump, namely a magnetically suspended centrifugal pump (MSCP), which has no shaft and operates as a noncontacting and bearingless pump. The impeller is suspended magnetically between the magnetic bearing and the driving motor. Hemolysis tests were performed in comparison with the Biopump (BP80, BioMedicus). The index of hemolysis (IH) was significantly lower in the MSCP than in the Biopump. In addition, a smaller gap in the MSCP induced lower hemolysis. In preliminary studies using mongrel dogs, the layer of thrombus adherent to the impeller was observed in a few hours, which impaired the pumping efficiency. However, by using an impeller coated with silicone, no aggregations of platelets or fibrin on the impeller were observed in 24 h of continuous pumping. In conclusion, the MSCP had a gentler influence on blood cells than the Biopump, and the impeller coated with silicone may contribute to the long-term pumping of the MSCP.

Animals↗
PubMed1996

Ubiquinone systems of the genus Cladosporium and morphologically similar taxa.

The ubiquinone (coenzyme Q) systems of 14 species of Cladosporium were determined. The genus was divided into two groups based on the distribution of the major ubiquinones, Q-10 and Q-10(H2). The group containing Q-10 consisted of six species, four of which were human pathogens, whereas the group containing Q-10(H2) consisted of eight plant pathogenic and/or saprophytic species. The results presented here agree with phylogenetic and physiological studies which have shown that the human-pathogenic species of Cladosporium represent a homogeneous, cohesive group.

Cladosporium↗
PubMed1996

Identification of the bud emergence gene BEM4 and its interactions with rho-type GTPases in Saccharomyces cerevisiae.

The Rho-type GTPase Cdc42p is required for cell polarization and bud emergence in Saccharomyces cerevisiae. To identify genes whose functions are linked to CDC42, we screened for (i) multicopy suppressors of a Ts- cdc42 mutant, (ii) mutants that require multiple copies of CDC42 for survival, and (iii) mutations that display synthetic lethality with a partial-loss-of-function allele of CDC24, which encodes a guanine nucleotide exchange factor for Cdc42p. In all three screens, we identified a new gene, BEM4. Cells from which BEM4 was deleted were inviable at 37 degrees C. These cells became unbudded, large, and round, consistent with a model in which Bem4p acts together with Cdc42p in polarity establishment and bud emergence. In some strains, the ability of CDC42 to serve as a multicopy suppressor of the Ts- growth defect of deltabem4 cells required co-overexpression of Rho1p, which is an essential Rho-type GTPase necessary for cell wall integrity. This finding suggests that Bem4p also affects Rho1p function. Bem4p displayed two-hybrid interactions with Cdc42p, Rho1p, and two of the three other known yeast Rho-type GTPases, suggesting that Bem4p can interact with multiple Rho-type GTPases. Models for the role of Bem4p include that it serves as a chaperone or modulates the interaction of these GTPases with one or more of their targets or regulators.

Amino Acid Sequence↗
PubMed1996

Dose response study of ipratropium bromide aerosol on maximum exercise performance in stable patients with chronic obstructive pulmonary disease.

BACKGROUND: Although the bronchodilating effect of inhaled anticholinergics has been established in patients with chronic obstructive pulmonary disease (COPD), their effects on exercise capacity are still controversial. Previous studies have suggested that the standard dosage hardly affects exercise tolerance, whereas higher doses might elicit an improvement. The aim of the present study was to determine the dose of ipratropium bromide aerosol that improves exercise performance using progressive cycle ergometry in patients with stable COPD. METHODS: Twenty men with stable COPD of mean (SD) age 69.2 (4.6) years and forced expiratory volume in one second (FEV1) 1.00 (0.37) 1 were studied in a randomised double blind manner. Each patient received ipratropium bromide in doses of 240 micrograms, 160 micrograms, 80 micrograms, 40 micrograms, and placebo from a metered dose inhaler (MDI) with an InspirEase spacer on five separate days. Spirometric parameters were assessed before and at 30, 60, 90, and 120 minutes after each inhalation, and pulse rate and blood pressure were also measured immediately before each spirometric measurement. Symptom limited progressive (20 watts/min) cycle ergometer exercise tests were performed 90 minutes after each inhalation. RESULTS: Ipratropium bromide in doses of 160 micrograms and 240 micrograms produced a greater increase in FEV1 than 40 micrograms or 80 micrograms ipratropium bromide at all time points. Doses of 160 micrograms and 240 micrograms ipratropium bromide also produced greater increases in maximal work load and maximal oxygen consumption than placebo, whereas 40 micrograms and 80 micrograms ipratropium bromide did not. There was a weak correlation between the change in FEV1 and the change in maximal work load (r = 0.45). No differences were found in pulse rate or blood pressure between the treatment and placebo groups, and no side effects were noted throughout the study. CONCLUSIONS: A dose of at least four times the standard dose of ipratropium bromide from an MDI with a spacer device was necessary to improve maximal cycle exercise capacity in patients with stable COPD. Although the data from cycle ergometry cannot be directly applied to exercise performed during day to day activities, it is conceivable that the recommended doses of ipratropium bromide do not elicit the optimal clinical benefits.

Aerosols↗
PubMed1996

Erythropoietin-producing adrenocortical carcinoma.

A 62-year-old Japanese male with an erythropoietin-producing adrenocortical carcinoma is presented. The elevated erythropoietin level and erythrocytosis returned to normal after surgical removal of a huge left adrenal tumor weighing 1,580 g. A histopathological diagnosis of adrenocortical carcinoma was made. Despite adjuvant combined chemotherapy, the patient died of lung and liver metastases 3.5 months after operation. Although the possibility that the elevated plasma erythropoietin level and erythrocytosis resulted from local kidney hypoxia, caused by pressure from the huge adrenal tumor, cannot be completely neglected, the positive cytoplasmatic evidence of immunoreactive erythropoietin in the carcinoma cells and the detection of a high erythropoietin level in the tumor extract on radioimmunoassay confirmed that this is a very rare case of erythropoietin-producing adrenocortical carcinoma.

Adrenal Cortex Neoplasms↗
PubMed1996

Mucinous adenocarcinoma of the male urethra.

We report a case of primary mucinous adenocarcinoma arising in the bulbomembranous urethra. The patient underwent radical cystectomy and total penectomy, followed by systemic chemotherapy. Metastases in lungs, skin, and lymph nodes (inguinal, iliac, para-aortic, and tracheobronchial) were found within 2 months after operation. We reviewed 37 cases of primary adenocarcinomas of the male urethra.

Adenocarcinoma, Mucinous↗
PubMed1996

Physiologic factors that determine the health-related quality of life in patients with COPD.

STUDY OBJECTIVE: To determine the physiologic factors that influence the health-related quality of life (HRQL) in patients with stable COPD and to identify the factors that most influence HRQL. METHODS: The Nottingham Health Profile (NHP) was used as a general HRQL measure and the Chronic Respiratory Disease Questionnaire (CRQ) was used as a disease-specific HRQL measure to investigate 132 patients with stable COPD, and measurements of HRQL were compared with physiologic measures. RESULTS: Vital capacity, FEV1, the ratio of the FEV1 to the FVC, diffusion capacity for carbon monoxide, diffusion capacity corrected for alveolar volume, lifetime cigarette consumption expressed as pack-years, and age were weakly correlated with several dimensions of both the NHP and the CRQ. Factor analysis reduced these variables to three factors. Two factors mainly referring to airflow limitation and diffusing capacity were weakly correlated with several dimensions of both the NHP and the CRQ. Logistic regression analysis identified 4 independent predictors of HRQL: airflow limitation (odds ratio [OR] = 0.59 to 0.69), diffusing capacity (OR = 0.75 to 0.82), pack-years (OR = 1.20 to 1.23), and age (OR = 2.13). The CRQ was more sensitive to impairment of HRQL than the NHP. CONCLUSIONS: The HRQL of patients with stable COPD is partly determined by airflow limitation, diffusing capacity, pack-years, and age. However, these factors could not predict the whole spectrum of HRQL, and the contribution of these factors to HRQL was limited. Therefore, HRQL should be measured directly in addition to physiologic measures.

Aged↗
PubMed1996

Captopril, an angiotensin-converting enzyme inhibitor, induced pulmonary infiltration with eosinophilia.

In this study, we investigated the association between the drug-induced pulmonary infiltration with eosinophilia (PIE) syndrome in a patient with hypertension and the angiotensin-converting enzyme inhibitor (ACE-I) captopril. Although the patient developed diffuse lung field infiltrates accompanied by productive cough and striking peripheral eosinophilia, these symptoms disappeared after termination of the administration of captopril, pronase and cephalexine. Furthermore, the results of the peripheral lymphocyte stimulation test, skin patch test and provocation test under informed consent showed a positive reaction only for captopril. Therefore, this patient was diagnosed as captopril-induced PIE syndrome.

Angiotensin-Converting Enzyme Inhibitors↗