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E Tamiya

Publications and source records attributed to E Tamiya.

53 records · Page 3Linked to original sources
PubMed1991

Development of acetylcholine sensor using carbon fiber (amperometric determination).

An enzyme sensor is developed using carbon fiber to measure acetylcholine concentration. The mechanism is based on the detection of H2O2 which is a product of the sequential enzyme reactions of acetylcholinesterase and choline oxidase. The fabrication of the electrode is described. The sensor is polarized at 1.2 V. Enzymes are co-immobilized in polyvinyl alcohol containing styryl pyrydinium (photo-crosslinkable polymer). A fast response time of 0.8 min is obtained. A linear correlation is observed between 0.2 and 1.0 mM. Other optimal operational conditions with respect to pH, temperature and stability are discussed. The use of carbon fiber containing co-immobilized enzymes could offer several novel advantages especially in neuroscience research. In conclusion, the aims of the present work are centered on carbon fiber electrode fabrication, immobilization and electrochemical measurements.

Acetylcholine↗
PubMed1991

[Prediction of coronary artery bypass graft flow--analysis of time density curve obtained from digital subtraction angiography].

UNLABELLED: To predict the coronary artery bypass graft(CABG) flow based on the time density curve(TDC) obtained from the digital subtraction aortograms(DSA), we developed a pulsatile CABG model (perfusion pressure 60, 130 mmHg, pulse rate 53, 126/min, cardiac output 3-7 l/min, diameter of the graft 2.1-6.0 mm). After positioning the regions of interest (ROI), we injected contrast medium (5-40 ml/sec, 5-40 ml) into the outlet conduit. Concerning the TDCs, we calculated appearance time(Ta), peak densities(Dp), peak time(Tp), disappearance time(Td), integral of TDC, delta Tp (difference of Tp between two ROI) and delta Ta (difference of Ta between two ROI). RESULTS: Perfusion pressure, graft flow and output curve were similar to those of patients with CABG. Ta, Tp, Td and delta Tp were affected by both the injection rate and the volume of the contrast medium; while Dp and the TDC integral were only affected by the latter parameter. Under the same conditions of contrast medium injection, the TDC depended strongly on graft flow, diameter of the graft, output and pulse rate. 21.6 + 0.92 pi.d2/4.delta 1/delta Tp.60 provided the most accurate estimation of CABG flow (r = 0.865, p less than 0.01). We conclude that densitometric analysis of DSA may be useful in the prediction of CABG flow.

Absorptiometry, Photon↗
PubMed1990

Microbiosensors.

Explore the source record for details and available documents.

Biosensing Techniques↗
PubMed1989

[Detection and significance of calcified coronary arteries by computed tomography].

To investigate whether coronary artery disease is detected noninvasively, we correlated calcification on computed tomography (CT) with coronary angiographic (CAG) findings in 90 consecutive patients including 48 with angina pectoris or myocardial infarction. The mean age was 52.2 years and 83% were men. CT scans without contrast enhancement (3 sec scan time) were obtained at 1 cm thickness from the ascending aorta to cardiac apex to identify calcification in coronary arteries. Results; CAG revealed of 50 patients, and stenosis was present more often at calcified vessels on CT. (table; see text) Calcification occurred more often in 2 or 3 vessel disease. However, stenotic segments were not always calcified. We conclude that CT is sensitive for the detection of calcification and an important method for the diagnosis of coronary artery disease.

Calcinosis↗
PubMed1988

DNA cleavage based on high voltage electric pulse.

A high voltage electric pulse was applied to DNA cleavage. The DNA cleavage reaction was dependent on the voltage amplitude, pulse number and pulse width. Radical scavengers and ESR data indicated the possibility that active species such as OH radical were strongly related to DNA cleavage.

DNA↗
PubMed1987

Tumor cell detection method using complement-mediated cytolytic reaction and imaging sensor system.

A novel tumor-detection system consisting of complement-mediated cytolytic reaction and an image processing system was developed for the simple and rapid determination of tumor cells. The present system consists of a CCD image sensor, image memory board, personal computer, and microscope. When monoclonal antibody 3C4, which is specific to the guinea pig hepatoma L-10, was added to cell suspension, only L-10 cytolysis occurred. Cytolysis caused a decrease in brightness of the cells observed by phase-contrast microscopy. The phase contrast image of the cells before cytolysis was converted to a digitalized signal and stored in computer memory. After cytolysis, a brightness threshold above that of lysed cells was subtracted from the digitalized signal and compared to the signal stored before reaction. L-10 cells in mixed cell suspension were determined specifically by the system. Measurement time was only 2 sec and overall time, including reaction time, was approximately 30 min. Since this method does not require a cell washing process, automation of the whole system is possible.

Animals↗
PubMed1987

Rapid detection of leukemia cells by use of a complement-mediated cytolytic reaction and an imaging sensor system.

We describe a system for detection of leukemia cells involving complement-mediated cytotoxic reaction and an image processing system, consisting of a charge-coupled-device image sensor, an image memory board, a personal computer, and a phase-contrast microscope. Then added to a cell suspension, monoclonal antibody specific to the fetal thymus antigen-1 of the mouse leukemia GRSL cell produced cytolysis of only GRSL cells. This cytolysis decreased the brightness of the cells observed by phase-contrast microscopy. The remaining brightness was subtracted from that of the phase-contrast image of the cells before cytolysis, which had been converted to a digital signal and stored in computer memory. Measurement time is 2 s. The time course for complete GRSL cytolysis, as measured with this system, is 12 min; overall measurement time, including reaction time, is approximately 15 min. GRSL cells in a suspension of mixed cells were determined specifically by the system.

Cell Count↗
PubMed1986

Electrical stimulation of hybridoma cells producing monoclonal antibody to cAMP.

Electrical stimulation was applied to hybridoma cells in order to activate metabolic activities and increase the monoclonal antibody production. Hybridoma cells that produce monoclonal antibody to adenosine 3':5'-cyclic monophosphate were placed on a transparent glass electrode immersed in medium and subjected to electric pulses (pulse shape, alternating rectangular; field strength, 4 X 10(3) V X m-1; frequency, 5 kHz; pulse mode, 0.5 min application and 4.5 min pause). After 48 h of incubation, the concentration of lactic acid in the medium reached 8.4 mM, approx. 30% higher than that obtained without electric stimulation. Similarly, cell growth rate was promoted by the electric stimulation, reaching a maximum stimulation after 40 h. When the hybridoma was cultured for 48 h with electrical stimulation, the antibody concentration in the medium reached 22.3 microgram X ml-1, approx. 10% higher than the control, with a concomitant 16% increase in cell concentration. Longer periods of electric pulse application, however, caused an inhibitory effect on the hybridoma growth. The most probable cause of the inhibition are reactive oxygen species such as superoxide and hydrogen peroxide, which are inevitably generated by electrolysis. The presence of superoxide dismutase (EC 1.15.1.1) reduced the inhibitory effects. In conclusion, metabolic activities including monoclonal antibody production were activated by the electrical stimulation.

Animals↗
PubMed1984

New cell fusion method using polymer membrane.

A porous polymer membrane of nitrocellulose or tetrafluoroethylene (TFE) was employed for fusion of Saccharomyces cerevisiae (AH22 and D13-1A) protoplasts. Protoplasts were adsorbed on the membrane with slight suction. Some part of the protoplasts was trapped in pores of the membrane as observed by electron microscopy. The membrane retaining protoplasts was placed on a selective medium. Several colonies appeared on the medium after 5-7 days incubation at 30 degrees C. The fusion of the two strains was ascertained by DNA content and genetic markers. Fusion frequency was 1.2 X 10(-6) in the case of the TFE membrane.

Cell Fusion↗
PubMedDate not supplied

Pulse immunoassay for human immunoglobulin G using antibody bound latex beads.

Pulse immunoassay was applied in the immunoassay of human immunoglobulin G (H-IgG). Antibodies to H-IgG were covalently immobilized on the surface of latex beads (1 microM). Immunoreaction of the antibody bound latex beads (Ab-L) and H-IgG was performed using electric pulses. Agglutination rate (AR), defined by the following equation, was used to estimate the immunoreaction rate (formula; see text) where Nn is the total number of beads forming n bead agglutinations. Each Nn was determined by analyzing photographs of the samples. When 140 microliter of Ab-L suspension (0.7%) containing H-IgG (6.7 X 10(-6) g ml-1) was reacted using electric pulses (peak height 2 kV cm-1, pulse width 20 microseconds, pulse frequency 8 kHz), AR increased sharply and reached 50% after 10 min. In contrast, when the same sample was reacted without electric pulses, AR increased very slowly and only reached 20% after 20 min. Therefore, the immunoreaction of H-IgG and Ab-L can be carried out more rapidly by applying electric pulses.

Agglutination↗