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Biomedical subjects

Y Asai

Publications and source records attributed to Y Asai.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Persistent left-sided superior vena cava diagnosed after flow-directed pulmonary artery catheterization; report of a case].

We describe a case of persistent left-sided superior vena cava discovered after insertion of a pulmonary artery (PA) catheter. The diagnosis was suggested by chest X-ray after PA catheter placement and was subsequently confirmed by an echocardiograph. A 68-year-old man was admitted to our ICU because of septic shock induced by MRSA enterocolitis. In order to monitor the hemodynamic state of the patient, a PA catheter was inserted through the left subclavian vein after placement of a central venous and flexible double lumen catheters through the right internal jugular and subclavian veins, respectively. A chest X-ray showed the PA catheter passing along the left border of the heart. An echocardiograph showed the PA catheter passing through the coronary sinus into the pulmonary artery. Anesthesiologists and intensivists should be aware of the occurrence of left-sided superior vena cava in order not to mistake catheters placed in it as being in the arterial circulation or malpositioned outside of the venous circulation.

Catheterization, Swan-Ganz↗
PubMed2001

[Effects of lumbar sympathetic ganglion block in a patient with acquired lymphangioma].

A 70-year-old woman developed lymphangioma following surgery for cervical cancer and subsequent radiotherapy. The operation was performed 12 years ago, and a swelling of lower extremities was recognized 8 years ago. Her lower extremities became greatly edematous, and leakage of lymph to the groin was observed. We performed bilateral lumbar sympathetic ganglion block. After the block, lymphedema was relieved dramatically, and the leakage of the lymph to the groin was gradually reduced. We conclude that lumbar sympathetic ganglion block may be very effective in some patients with acquired lymphangioma.

Aged↗
PubMed2001

[Prevalence, awareness, treatment, and control of hypertension in Japanese rural communities].

BACKGROUND: In Japan, a national survey indicated that only 7% of hypertensive patients had a blood pressure less than 140/90 mmHg. There have been no reports of studies investigating all of the prevalence of hypertension, the percentage of subjects who are aware of hypertension, the percentage being treated, and the percentage that are well-controlled (awareness, treatment and control, respectively) among hypertensives in the Japanese general population. OBJECTIVE: To investigate the prevalence of hypertension, and awareness, treatment and control of hypertension among hypertensives in a Japanese rural population. DESIGN: A cross-sectional analysis of base-line data of the Jichi Medical School Cohort Study. SETTING: Twelve rural communities is 8 prefectures in Japan. PARTICIPANTS: Community-dwelling people who participated in the health examination program in 1992-1995. MAIN OUTCOME MEASURES: Blood pressure (BP) measured once in the sitting position after a 5-minute rest using oscillometric automatic BP monitors (BP203RV-II; Nippon Colin, Japan), and history of hypertension assessed using a self-administered questionnaire. RESULTS: We analyzed data from 11,302 subjects (4,415 men and 6,887 women). The mean (standard deviation) age was 55(12) years for men and 55(11) years for women. Mean systolic BP and diastolic BP levels were, respectively, 131(21) mmHg and 79(12) mmHg for men and 128(21) mmHg and 76(12) mmHg for women. Prevalence of hypertension (systolic BP > or = 140 mmHg or diastolic BP > or = 90 mmHg or on antihypertensive medication) was 37% for men and 33% for women. Percentages for awareness (on medication or present past history), treatment and control (both systolic BP < 140 mmHg and diastolic BP < 90 mmHg) were, respectively, 39%, 27% and 10% for men and 46%, 38% and 13% for women. CONCLUSIONS: About one third of the study popUlation were hypertensive, and awareness, treatment and control of hypertension among the hypertensives were 43%, 34% and 12%, respectively. Less than half of the hypertensives were well-controlled even when measurement bias was considered. In the rural Japanese population, improvements are required with regard to awareness, treatment and control of hypertension.

Adolescent↗
PubMed2000

Intermolecular cross-linking between the periplasmic Loop3-4 regions of PomA, a component of the Na+-driven flagellar motor of Vibrio alginolyticus.

PomA and PomB form a complex that conducts sodium ions and generates the torque for the Na(+)-driven polar flagellar motor of Vibrio alginolyticus. PomA has four transmembrane segments. One periplasmic loop (loop(1-2)) connects segments 1 and 2, and another (loop(3-4)), in which cysteine-scanning mutagenesis had been carried out, connects segments 3 and 4. When PomA with an introduced Cys residue (Cys-PomA) in the C-terminal periplasmic loop (loop(3-4)) was examined without exposure to a reducing reagent, a 43-kDa band was observed, whereas only a 25-kDa band, which corresponds to monomeric PomA, was observed under reducing conditions. The intensity of the 43-kDa band was enhanced in most mutants by the oxidizing reagent CuCl(2). The 43-kDa band was strongest in the P172C mutant. The motility of the P172C mutant was severely reduced, and P172C showed a dominant-negative effect, whereas substitution of Pro with Ala, Ile, or Ser at this position did not affect motility. In the presence of DTT, the ability to swim was partially restored, and the amount of 43-kDa protein was reduced. These results suggest that the disulfide cross-link disturbs the function of PomA. When the mutated Cys residue was modified with N-ethylmaleimide, only the 25-kDa PomA band was labeled, demonstrating that the 43-kDa form is a cross-linked homodimer and suggesting that the loops(3-4) of adjacent subunits of PomA are close to each other in the assembled motor. We propose that this loop region is important for dimer formation and motor function.

Anti-Bacterial Agents↗
PubMed2000

Coupling ion specificity of chimeras between H(+)- and Na(+)-driven motor proteins, MotB and PomB, in Vibrio polar flagella.

We have shown that a hybrid motor consisting of proton-type Rhodobacter sphaeroides MotA and sodium-type VIBRIO: alginolyticus PomB, MotX and MotY, can work as a sodium-driven motor in VIBRIO: cells. In this study, we tried to substitute the B subunits, which contain a putative ion-binding site in the transmembrane region. Rhodobacter sphaeroides MotB did not work with either MotA or PomA in Vibrio cells. Therefore, we constructed chimeric proteins (MomB), which had N-terminal MotB and C-terminal PomB. MomB proteins, with the entire transmembrane region derived from the H(+)-type MotB, gave rise to an Na(+) motor with MotA. The other two MomB proteins, in which the junction sites were within the transmembrane region, also formed Na(+) motors with PomA, but were changed for Na(+) or Li(+) specificity. These results show that the channel part consisting of the transmembrane regions from the A and B subunits can interchange Na(+)- and H(+)-type subunits and this can affect the ion specificity. This is the first report to have changed the specificity of the coupling ions in a bacterial flagellar motor.

Amino Acid Sequence↗
PubMed2000

In vivo imaging of adenovirus-mediated over-expression of dopamine D2 receptors in rat striatum by positron emission tomography.

PET was used to provide in vivo imaging of the over-expression of dopamine D2 receptor (D2R) induced by adenovirus vector-mediated gene transfer in rat striatum. The uptake of three kinds of D2R-specific ligands, [11C]raclopride, [11C]nemonapride and [11C]N-methylspiperone, measured by PET was higher in the striatum injected with the vectors for D2R than the contralateral striatum injected with a control vector 2-3 days after injection. However, the uptake of [11C]SCH 23390, a dopamine D1 receptor specific ligand, or [11C]beta-CIT-FP, a dopamine transporter specific tracer, was not different between bilateral striata. Co-injection of excess unlabeled raclopride inhibited the uptake of [11C]raclopride. At day 16 the increased uptake of [11C]raclopride declined to basal level, consistent with past in vitro assessment of this vector. In vivo imaging of D2R will permit longitudinal assessment of the efficiency of this and similar vectors in rat brain that can be related to functional changes being observed.

Adenoviridae↗
PubMed2000

Lympholeukemia in madai Pagrus major in Japan.

Lympholeukemia has been occurring to an epizootic extent with mass mortality in 1 and 2 yr old madai (= Japanese red sea bream) Pagrus major in the winter season (October-May) in the western regions of Japan since 1975. Diseased fish displayed severe anemia and markedly increased numbers of neoplastic lymphocytoid and lymphoblastoid cells in the blood. Neoplastic cells originated in the splenic lymphatic cells and systemically caused severe metastatic lesions in the heart, liver, kidney, digestive tracts, gills and the lateral musculature. Electron microscopy revealed adeno-like viral particles (78 to 83 nm in diameter) in the nucleus of lymphoblastoid cells which appeared in the early prevalent stage but no viral particles in the lymphocytoid cells or plasmacytoid cells, which subsequently increased in number. In this paper, we describe light and electron microscopic features of neoplasms and neoplastic cells.

Animals↗
PubMed2000

Formation and stability of the dispersed particles composed of retinoic acid, sesame oil and phosphatidylcholine.

All trans-retinoic acid (RA) was dispersed by sonication with soybean phosphatidylcholine (PC). The particle size in the dispersion was increased to 240 nm up to the RA mol fraction range (X(RA)) of 0.4. At X(RA)=0.5, the RA/PC mixture was difficult to disperse and the macroscopic oil/water phase separation was observed. On the other hand, by the addition of sesame oil (SO) to RA (molar ratio of RA:SO=1:1), stable aqueous dispersions (diameter: 40-80 nm) were obtained in the mol fraction range RA and SO mixture (X(M)) of 0.1-0.8. In order to clarify these dispersal mechanism, the dispersed particles were characterized and the interaction among RA, SO and PC was investigated using several physicochemical techniques. The trapped aqueous volume inside the RA/PC particles was determined using the aqueous space marker, calcein and it was increased with the addition of RA into small unilamellar vesicles of PC. On the other hand, that of RA/SO/PC particles was decreased remarkably with increase in X(M) and the decline in the fraction of vesicular particles was also confirmed by fluorescence quenching of N-dansylhexadecylamine in the PC membrane by the addition of the quencher CuSO(4). These results indicate that the interaction of RA with PC bilayers and the structure of RA/PC mixture will be changed by the addition of SO.

Algorithms↗
PubMed2000

Expression of inducible nitric oxide synthase and Fas/Fas ligand correlates with the incidence of apoptotic cell death in atheromatous plaques of human coronary arteries.

It was recently reported that inducible nitric oxide synthase was expressed in advanced atheromatous plaques. So we investigated the effect of NO or peroxynitrite reactive product of NO or O(2)(-) released by iNOS induced in macrophages or T lymphocytes on inflammatory cells in atheromatous plaques of human coronary arteries by immunohistochemistry. We found that iNOS was expressed in T lymphocytes and macrophages in T lymphocytes and macrophages coexisted advanced atheromatous areas. Most of the smooth muscle cells are not coexisted with T lymphocytes. We could not find iNOS in those smooth muscle cells. Only a small number of iNOS-positive smooth muscle cells were found close to T lymphocytes and macrophages. Markers for apoptotic cells induced in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) showed that many apoptotic T lymphocytes and macrophages existed near iNOS induced cells. Fas and Fas ligand were expressed in almost same areas that iNOS was expressed. By double-label immunostaining, Fas was expressed in T lymphocytes but Fas ligand was expressed in macrophages and in some T lymphocytes. These results suggest that NO from iNOS induces Fas and Fas ligand-mediated apoptosis and associates with regression of atherosclerosis. On the other hand, nitrotyrosine was detected wider areas than iNOS. So peroxynitrite from iNOS damages cells and tissues widely and may associate with progression of atherosclerosis. These results suggest an important role of iNOS in mediating both regressive changes and progressive change in atheromatous plaques.

Aged↗
PubMed2000

Grepafloxacin inhibits tumor necrosis factor-alpha-induced interleukin-8 expression in human airway epithelial cells.

We examined the effect of grepafloxacin (GPFX), a new fluoroquinolone antimicrobial agent, on interleukin-8 (IL-8) expression in tumor necrosis factor-alpha (TNF-alpha)-stimulated human airway epithelial cells (AEC). GPFX inhibited IL-8 protein production as well as mRNA expression in a concentration-dependent manner (2.5 - 25 micro g/ml), but the inhibition of IL-8 expression by corresponding concentrations of GPFX to serum and airway lining fluids was not complete. We discuss the modulatory effect of GPFX on IL-8 production in the context of its efficacy on controlling chronic airway inflammatory diseases.

Anti-Infective Agents↗
PubMed2000

Characterization of the physicochemical properties of the micelles by the novel platelet activating factor receptor antagonist E5880.

E5880, a novel platelet activating factor receptor antagonist, was dispersed in the buffer solution (4.8 mM citric acid, 10% lactose, pH 2.8) for the preparation of an injectable formulation and the physicochemical properties of the micelles were characterized. The critical micelle concentration of E5880 was 0.12 mM. Using the area per molecule results, the critical packing parameter was calculated and showed that the structure was spherical and the number of molecules in the aggregates was 46. The diameter of the micelle was 5.6 nm. The micropolarity around the hydrocarbon region of the micelle was similar to that of isobutanol.

Algorithms↗
PubMed2000

Regulation by intracellular glutathione of TNF-alpha-induced p38 MAP kinase activation and RANTES production by human pulmonary vascular endothelial cells.

BACKGROUND: We have previously shown that p38 mitogen-activated protein (MAP) kinase regulates tumor necrosis factor-alpha (TNF-alpha)-induced RANTES production by human pulmonary vascular endothelial cells, and that sensitivity to TNF-alpha is inversely correlated with cellular reduction and oxidation (redox) state. However, a regulatory role of intracellular glutathione (GSH) in TNF-alpha-induced p38 MAP kinase activation and p38 MAP kinase-mediated RANTES production has not been determined. In the present study, therefore, we extended our previous studies and focused on redox regulation on p38 MAP kinase activation. METHODS: Human pulmonary vascular endothelial cells were exposed to N-acetylcysteine (NAC) or buthionine sulfoximine (BSO), and then TNF-alpha-induced p38 MAP kinase activation and p38 MAP kinase-mediated RANTES production were determined. RESULTS: The results showed that 1) NAC attenuated TNF-alpha-induced p38MAP kinase activation and RANTES production 2) SB 203580 as the specific inhibitor of p38 MAP kinase activity attenuated TNF-alpha-induced RANTES production 3) BSO facilitated TNF-alpha-induced p38 MAP kinase activation and RANTES production 4) SB 203580 attenuated BSO-mediated facilitation of TNF-alpha-induced RANTES production. CONCLUSIONS: These results indicated that TNF-alpha-induced p38 MAP kinase activation and p38 MAP kinase-mediated RANTES production by human pulmonary vascular endothelial cells are inversely regulated by intracellular GSH levels.

Acetylcysteine↗
PubMed2000

Interaction of ubiquinone-10 with dipalmitoylphosphatidylcholine and their formation of small dispersed particles.

Stable aqueous dispersions of ubiquinone-10 (UQ) were obtained by cosonication with dipalmitoylphosphatidylcholine (DPPC) in the UQ mole fraction range 0.1-0.7. To clarify the dispersal mechanism, the dispersed particles were characterized, and the interaction between UQ and DPPC was investigated using several physicochemical techniques. Dynamic light scattering (DLS) measurements showed that the diameter of the dispersed particles was 50-70 nm. A limited amount of UQ was incorporated into DPPC bilayer membranes (approximately 5 mol%). The trapped aqueous volume inside the particles was determined fluorometrically using the aqueous space marker calcein, and the volume in the UQ/DPPC particles decreased remarkably with the addition of UQ into small unilamellar vesicles of DPPC. The decline in the fraction of vesicular particles was also confirmed by fluorescence quenching of N-dansylhexadecylamine in the DPPC membrane by the addition of the quencher CuSO4. These results indicate that the excess UQ separated from the DPPC bilayers is stabilized as emulsion particles by the DPPC surface monolayer.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed2000

Comparison of the effect of lipid A analog E5531 and the lipid A from Escherichia coli on phospholipid membrane properties.

The effect of the lipid A analog E5531 on the phospholipid membrane was compared with that of the lipid A from Escherichia coli (EC). E5531 decreased the phase transition temperature of dipalmitoylphosphatidylcholine (DPPC) membrane and increased the fluidity and micropolarity. On the other hand, the effect of EC on the membrane was contradictory. These results suggested that the reason for the difference of biological effects of these two lipid A would be caused by the differences from the effect on the cell membranes.

Cell Membrane↗
PubMed2000

The effect of the membrane fluidity on pharmacokinetics for lipid A analog E5531.

The effect of the dispersing procedure on the aggregate size, membrane fluidity and the pharmacokinetics were evaluated for the lipid A analog E5531. The size of the aggregates prepared by the pH-jump method (pH 11.0-->7.3) was decreased, reaching 20 nm with increasing dispersing time in 0.003 N NaOH (pH 11.0). The membrane fluidity of the aggregates increased with increasing dispersing time. When prepared by the normal dilution method (pH 7.3-->7.3), the size of the aggregates remained constant at 150 nm and the membrane fluidity was smaller compared to samples prepared by the pH-jump method. Using samples with different degrees of hydration and different membrane fluidities prepared by the pH-jump method, the pharmacokinetics after intravenous administration into rats were evaluated, and the data obtained confirmed that the membrane fluidity was correlated with the pharmacokinetics in rat. In addition, E5531 vials were stable for 24 months at room temperature when used within 24 hr after reconstitution.

Animals↗
PubMed2000

A temperature study on critical micellization concentration of the novel platelet-activating factor receptor antagonist E5880 in water by electric conductivity measurements.

To clarify the behavior of the novel platelet-activating factor (PAF) receptor antagonist E5880 in aqueous solution, electric conductivity was measured at different temperatures (every 5 degrees C), ranging from 15 degrees C to 50 degrees C. Critical micellization concentration (CMC) of E5880 was dependent on the temperature; at 30 degrees C, the CMC value was smallest (0.143 mM). Below that temperature, the enthalpy for formation of the micelle (delta Hm0) was positive, and the formation of micelles was endothermic; above that temperature, delta Hm0 was negative, and the formation of micelles was exothermic.

Drug Administration Routes↗
PubMed2000

Characterization of the physicochemical properties of the micelles of platelet-activating factor (C18:0).

The purpose of this study was to clarify the physicochemical properties of the micelles of platelet-activating factor (PAF; C18:0). The critical micelle concentration (CMC) of PAF (C18:0) was determined (0.20 microM) using fluorescence techniques. The fluidity and the micropolarity of the PAF (C18:0) micelle were similar to those of the micelle of stearoyl lysophosphatidylcholine.

Anilino Naphthalenesulfonates↗