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Biomedical subjects

N Asada

Publications and source records attributed to N Asada.

13 recordsLinked to original sources
PubMed1990

Potential usefulness of an artificial neural network for differential diagnosis of interstitial lung diseases: pilot study.

An artificial neural network approach was applied to the differential diagnosis of interstitial lung diseases. The neural network was designed to distinguish between nine types of interstitial lung diseases on the basis of 20 items of clinical and radiographic information. A data base for training and testing the neural network was created with 10 hypothetical cases for each of the nine diseases. The performance of the neural network was evaluated by means of receiver operating characteristic analysis. The decision performance of the neural network was high; it was comparable to that of chest radiologists and superior to that of senior radiology residents. The preliminary results strongly suggest that the neural network approach has potential utility in the computer-aided differential diagnosis of interstitial lung diseases.

Computer Simulation↗
PubMed1990

[Pathophysiological analysis of cardiac function by computer processing of echocardiograms].

Automatic image processing system has been developed for analysis of cardiac function with echocardiograms. Echograms of apical long axis view were transferred to microcomputer system and processed to display three dimensional images of left ventricular myocardium. With this technology, analysis of left ventricular wall thickness in three dimensional manner revealed pathophysiological changes in ischemic heart disease.

Coronary Disease↗
PubMed1988

A new method of three dimensional analysis of left ventricular wall motion.

The three dimensional (3D) shape of left ventricles (LV) was reconstructed from gated blood pool emission computed tomography (GECT) to assess regional LV wall motion. The 3D LV shape was created using LV boundaries detected by a threshold method. Based on the length from each LV boundary to the end diastolic LV center of mass, regional percent shortening and phase of the first harmonic by Fourier analysis were calculated to create 3D functional images. These images clearly demonstrated the 3D extent of wall motion abnormality. In addition, the same 3D analysis was applied to biplane X-ray left ventriculography (LVG) by assuming that LV short axis sections were elliptic. Results of planar imaging, 3D analysis of GECT, 3D analysis of LVG and conventional LVG findings correlated well with each other. The 3D analysis of GECT is useful for non invasive quantitative analysis of LV wall motion.

Adult↗
PubMed1988

Formation and the inhibition of reaction plug in mated Drosophila--study of a primitive defense reaction.

Formation and inhibition of a reaction plug in the course of insemination reaction in Drosophila (Diptera) were investigated. When the reaction plug was formed in the vagina, fecundity was significantly reduced in interspecific crosses although the reaction plug did not affect the oviposition in intraspecific crosses. Some phenoloxidase blockers were found to be the effective inhibitors. The formation of the reaction plug was likely to be the consequence of polymerization and/or conformational change(s) of phenol-containing substance(s) involving nearly the same course of the melanization cascade reaction studied as a self-defense system in other insects.

Animals↗
PubMed1988

Left ventricular image processing of 2-D echocardiograms and 3-D reconstruction of the left ventricle.

Image processing systems of echocardiograms are discussed. The left ventricular boundary on every 2-D echocardiogram on consecutive frames digitized with an ECG (electrocardiogram) signal is traced automatically after initial manual drawing of the boundary on an end diastolic image. Various cardiac parameters are derived from these left ventricular boundaries over a cardiac cycle: volume change, regional wall motion, percentage shortening of regional wall and so on. 3-D shapes of the left ventricle and myocardium are reconstructed from several sequences of cross-sectional echo data. Cardiac parameters are also derived from these 3-D shapes and are shown on 3-D shapes as functional images of 3-D left ventricle.

Echocardiography↗
PubMed1987

New modified activated partial thromboplastin time and prothrombin time methods using a synthetic chromogenic substrate in combination with diazotization.

A chromogenic substrate, H-D-Phe-Pip-Arg-pNA (S-2238) is a highly specific substrate to thrombin and releases p-nitroaniline (pNA) by the action of thrombin. We describe new modified APTT and PT methods using S-2238 in combination with the diazotization of pNA. In the modified APTT method, 100 microliter citrated plasma (diluted to 10-fold), 90 microliter 1 mM S-2238, 100 microliter 20 mM CaCl2 and 100 microliter Actin were mixed in an ice-bath, then incubated for 8 min at 37 degrees C. The reaction was stopped, and the generated pNA was diazotized by adding the following solutions sequentially: 975 microliter 0.04% sodium nitrite, 975 microliter 0.3% ammonium sulfamate and 975 microliter 0.07% N-(l-naphthyl)-ethylenediamine dihydrochloride. Diazotization changed pNA from yellow to pink. Then, absorbance at 545 nm was read, and values were expressed as thrombin units/ml plasma. In the modified PT method, 100 microliter citrated plasma (diluted to 20-fold), 90 microliter 1 mM S-2238 and 200 microliter tissue thromboplastin-C solution were mixed and processed as above. Correlations of the present modified APTT and APTT methods, and of modified PT and PT methods were significant (r = 0.426, p less than 0.01 and r = 0.561, p less than 0.01, respectively).

Aniline Compounds↗
PubMed1987

Left ventricular image processing.

Left ventricular image processing methods of x-ray cineangiocardiograms and ultrasound echocardiograms are discussed. 3-D reconstruction methods of the left ventricle from ultrasound echocardiograms and magnetic resonance images are also discussed. Boundary detection of the left ventricle and the quantitative analysis of the left ventricular function and wall motion are discussed. To reconstruct 3-D shapes, we need several cross sectional shapes or silhouettes of the left ventricle. Several cross sectional echo images of apical long axis view are taken by changing the angles of rotation of the probe of echo transducer around its axis. Gated multi-phase MRI method is used to obtain each 2 cross sectional images in transverse, coronal and sagittal directions. Some results of 3-D shapes of the left ventricle and myocardium reconstructed are shown and 3-D functional images which give us regional functions of the left ventricular wall on three dimensional shape are shown.

Cineangiography↗
PubMed1985

Influence of pH change on redox state and CCK-induced secretion in isolated perfused rat pancreas.

The isolated perfused rat pancreas was used to examine the influence of the acid-base status of the perfusing solution on the redox states of cytochromes and secretory responses. Lowering the pH in a perfusing solution (pHe) from 7.3 to 6.8 induced simultaneous oxidation of cytochromes aa3, b, and c + c1, and further lowering to 6.0 induced larger oxidation of the cytochromes. Raising the pHe from 7.3 to 8.0 induced reduction of the cytochromes. Continuous stimulation with synthetic C-terminal octapeptide of cholecystokinin (CCK-8) at 100 pM induced the maximum secretory responses (pancreatic juice flow, protein output, and amylase output) during perfusion with the standard solution. The responses were not inhibited at pHe 6.8 but were inhibited significantly at pHe 6.0 or 8.0. The responses induced by stimulation with 20 pM CCK-8 were completely inhibited when pHe was lowered to 6.0 and CaCl2 was removed from the perfusing solution.

Adenosine Triphosphate↗
PubMed1985

Production of the modified form of human plasminogen by alpha 2-macroglobulin-plasmin complexes.

It has been speculated that the modified form of plasminogen, a precursor of proteolytic enzyme plasmin in plasma, plays an important role in fibrinolysis in the blood. The present study was undertaken to examine the production by alpha 2-macroglobulin-plasmin complexes. alpha 2-Macroglobulin-plasmin complexes were purified from urokinase-activated plasma by affinity chromatography on lysine-Sepharose and gel filtration on Ultrogel AcA 22. The plasmin complex converted native plasminogen into the modified form more easily in the presence of epsilon-aminocaproic acid. The modification of native plasminogen by alpha 2-macroglobulin-bound plasmin was completely inhibited by aprotinin, and partly by soybean trypsin inhibitor. alpha 2-macroglobulin-bound plasmin produced modified plasminogen in human plasma where potent plasmin inhibitors exist, though the degree of production was small. The present results support the speculation of the important role of the modified form in vivo.

Animals↗