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Biomedical subjects

A Takeuchi

Publications and source records attributed to A Takeuchi.

At least 307 records · Page 17Linked to original sources
PubMed1988

Augmentation of coronary bypass graft flow induced by dipyridamole and its relation to bypass graft patency.

To evaluate the effect of dipyridamole on coronary bypass graft flow, 10 mg of dipyridamole was injected intravenously, during the measurement of graft flow, at the time of surgery. Its concentration in serum was measured and compared with that after oral administration. In 50 individual vein grafts performed on 35 patients, graft flow increased from 65 +/- 37 to 96 +/- 55 ml/min (p less than 0.001) after the dipyridamole injection and the arterial pressure decreased slightly. In 40 grafts whose graft flow was increased by more than 10 ml/min by dipyridamole, the patency rate (at 5 weeks) was 98 per cent, whereas that of the 10 other grafts, which responded poorly, was only 50 per cent (p less than 0.01). The serum concentration of dipyridamole, 3 minutes after intravenous injection, was 1.46 +/- 0.68 micrograms/ml, while the level of orally administered dipyridamole, in 3 groups of patients who were given 50 mg, 75 mg and 100 mg, three times a day, respectively, was steady, being 0.68 +/- 0.20 micrograms/ml, 1.43 +/- 0.41 micrograms/ml and 1.73 +/- 0.50 micrograms/ml, 2 hours following ingestion. We concluded that intravenous dipyridamole increases the graft flow and that a better patency is obtained in those grafts in which the graft flow is increased by more than 10 ml/min. It is also expected that routine doses of oral dipyridamole possibly increase the graft flow after coronary bypass surgery.

Administration, Oral↗
PubMed1988

A personal computer-based arrhythmia generator based on mathematical models of cardiac arrhythmia.

A personal computer-based arrhythmia generator has been developed based upon mathematical models of modulated parasystole and the related equations. A system of nonlinear difference equations is used to generate the time series of RR intervals of ECG that contain normal as well as ectopic QRS waves. The ECG waveform is synthesized according to the computed RR interval and the type of QRS wave and output via DA converter in a real-time base. Various types of ECGs with ventricular ectopic beats and those with very long periods were generated by selecting values for a small number of model parameters. This method requires neither large RAM nor external memory for storing a library of arrhythmic ECGs. The theory, hardware design, software implementation on a personal computer, and experimental reconstruction of clinical ECGs based on the model are discussed.

Arrhythmias, Cardiac↗
PubMed1988

Inhibition of neutrophil and monocyte functions by the monoclonal antibody TM2.

The ability of the monoclonal antibody termed TM2 to inhibit chemiluminescence generation by granulocytes and monocytes was examined. TM2 could inhibit the chemiluminescence generation of these cells when they were stimulated by all the stimuli presented. It seems that TM2 binds to the surface antigen of phagocytic cells which is important in the generation of free radicals.

Animals↗
PubMed1988

The P wave in the magnetocardiogram.

The P wave of the magnetocardiogram (MCG) was investigated in normal subjects and in patients with right and left atrial overloading. In normal subjects, the MCG P wave was positive at right lower sternal sites and negative in the other portions. The current source deduced from the MCG and the isomagnetic map was directed inferiorly and to the left throughout the entire phase of atrial activation. In patients with right atrial overloading, the direction of the current source deduced from the MCG was similar to that of normal subjects, but its amplitude was significantly greater. In left atrial overloadings, a negative-positive biphasic P wave was seen more frequently than in normal subjects at left parasternal sites. In the late phase of atrial activation, the MCG could detect the two dipoles, i.e. one directed inferiorly and other directed to the left. These dipoles might correspond to right and left atrial activities, respectively. These results show that the MCG might add useful information on current source to the conventional electrocardiogram.

Adult↗
PubMed1988

Isomagnetic maps in right ventricular overloading.

Isomagnetic maps were recorded in normal subjects and in patients with systolic overloading of the right ventricle. The isomagnetic maps examined in this study indicated the instantaneous current source of the heart by applying the "corkscrew rule." The magnetic field recorded by a second derivative gradiometer detected clearly the cardiac current source from the right ventricle, which is located close to the anterior chest wall, and improved diagnostic sensitivity. Moreover, the isomagnetic map showed multiple dipoles, which are difficult to detect in the electrocardiogram or isopotential map. These results suggest that the magnetocardiogram provides useful information on current sources to supplement information obtained by the conventional electrocardiogram.

Adult↗
PubMed1988

Analysis of the T wave of the magnetocardiogram in patients with essential hypertension by means of isomagnetic and vector arrow maps.

Magnetocardiograms (MCGs) of 50 normal subjects and 40 patients with essential hypertension were recorded to determine the value of the MCG for detecting abnormal repolarization. Among the patients with essential hypertension, there were nine cases (22.5%) in whom isopotential maps did not show rightward repolarization vectors but isomagnetic and vector arrow maps showed a rightward repolarization vector in some areas in addition to the normal repolarization vector. Departure maps of the ECG showed an increased repolarization vector directed anteriorly in some of these cases. The repolarization abnormality was recognized in only the MCG departure map in four cases, while no case showed abnormality in only the ECG departure map. With the progress of hypertension, the repolarization abnormality was seen more frequently and its detection using the MCG was higher than that using the ECG. Furthermore, multiple dipoles were detected more frequently from the MCG than from the ECG. Thus the MCG seems more useful than the ECG in the analysis of repolarization abnormalities in essential hypertension.

Adult↗
PubMed1988

Inhibition of neutrophil chemotaxis by a monoclonal antibody (TM316).

A monoclonal antibody, TM316, IgM kappa, was raised against the human monocytoid leukaemia cell line THP-1, and was shown to inhibit polymorphonuclear leucocyte (PMN) chemotaxis. The molecular weight (MW) of the protein on the PMN membrane with which TM316 bound was about 78,000. TM316 inhibited the chemotactic response of human PMN induced by at least three kinds of chemotactic factors (activated serum, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP), and a lymphocyte-derived chemotactic factor (LDCF)) to the same extent. The extent of inhibition of chemotaxis by TM316 was strongly correlated with the quantity of cellular surface antigen recognized by TM316, when a cell sorter was used for analysis. TM316 did not alter the number of Fc or complement receptors of PMN, nor did it affect luminol-enhanced chemiluminescence (CL), lysosomal enzyme release, adherence, or superoxide anion generation by PMN. TM316 seemed to recognize a common surface antigen which was necessary only for the process of chemotaxis.

Animals↗
PubMed1988

Coronary artery bypass grafting by utilizing the internal mammary artery graft in 100 Japanese patients.

The internal mammary artery (IMA) grafting for myocardial revascularization was performed in 100 Japanese patients during a three-year period. There were 86 males and 14 females with the mean age of 58 +/- 9 (37 approximately 75 year-old). Unilateral IMA was used in 88 patients and bilateral IMA was used in 12 patients. Sequential IMA grafting was performed in 5 patients. The sites of IMA grafting were 91 left anterior descending arteries (LAD), 16 diagonal branches, 8 circumflex arteries and 2 right coronary arteries. Saphenous vein or gastroepiploic artery was concomitantly used to bypass the other coronary arteries in 90 patients. The number of distal anastomosis ranged from 1 to 6 and the mean was 2.8 per patient. Two patients died within 30 days and one patient died at 3 months after surgery. Perioperative myocardial infarction was noted in 3 patients. Symptomatic relief was obtained in 94 (97%) of 97 survivors. The patency of the IMA graft at mean 2.2 postoperative months was 97% (58/60) in LAD, 100% (14/14) in the diagonal branch, 100% (5/5) in the circumflex artery, 100% (1/1) in the right coronary artery, and 98% (78/80) in over-all grafted coronary arteries. Pre- and postoperative exercise thallium scintigraphy in 13 patients, who received the IMA graft to severely stenosed LAD, showed significant improvement of the washout ratio (from 33.1 +/- 16.9% to 47.4 +/- 14.8%) which was nearly equivalent to that of the saphenous vein graft to LAD (from 24.8 +/- 6.2% to 48.1 +/- 6.6%, n = 7).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Angiographic comparison of the internal mammary artery graft and the saphenous vein graft within 2 months and 6 to 12 months after coronary artery bypass surgery.

Angiographic status of the saphenous vein graft (SVG) and the internal mammary artery graft (IMAG) anastomosed to the left anterior descending artery were compared at two different postoperative periods; - within 2 months and at 6 to 12 months after the operation. In 50 SVGs and 35 IMAGs which were studied at the early postoperative period, the rate of intact, stenosed and occluded grafts were almost the same in these two kinds of grafts. However, in 35 SVGs and 25 IMAGs which were studied at the later period, the stenosis of SVG increased significantly while IMAG remained intact. The rate of intact, stenosed and occluded grafts at postoperative 6 to 12 months were 71%, 23% and 6% in SVG, and 88%, 8% and 4% in IMAG, respectively. Considering the better angiographic quality of IMAG, use of IMAG to bypass the most important coronary artery should be considered especially when the patients are younger.

Constriction, Pathologic↗
PubMed1988

[Evaluation of the system performance and clinical images of the single photon emission computed tomography for head using ring arranged detector].

To evaluate the system performance, several preoperational fundamental tests of single photon emission computed tomography (SPECT) were carried out. Spatial resolutions (FWHM) measured with the point-spread functions of a 99mTc line source were 12.5 mm with a high resolution (HR) collimator and 17.2 mm with a high sensitivity (HS) collimator respectively. Slice thicknesses (FWHM) obtained from the profile curves of slice images were 17.5 mm (HR) and 29.0 mm (HS) at the center of rotation. System sensitivities were 5.4 kcps/slice (HR) and 27.8 kcps/slice (HS). Uniformities calculated from the SPECT images of a pool phantom were 4.7% (HR) and 2.7% (HS) at the condition of 3,000 kcounts to be acquired. SPECT images of the HEADTOME SET-031 were considered very useful to diagnose the cerebrovascular disease.

Brain↗
PubMed1988

[Arterial grafts for myocardial revascularization; experience of 65 internal mammary artery and gastroepiploic artery graftings].

From November, 1984, to February 1987, internal mammary artery (IMA) and gastroepiploic artery (GEA) graftings to coronary arteries were performed in 65 patients. Of these patients, 58 unilateral IMAs, 6 bilateral IMAs, 2 GEAs were utilized. The hospital mortality was 3.2% but no cardiogenic death occurred. Fifty-eight (89%) patients became asymptomatic after surgery. Postoperative angiography performed from 1 to 3 months after operation showed excellent patency in 57 (96%) IMAs and 2 (100%) GEAs. On the other hand, the patency of saphenous vein graft done at the same period were 88%. GEAs were used for 2 reoperated cases and revealed good patency and relief of symptoms without surgical complication. Cavitron ultrasonic surgical aspirator (CUSA) was used to dissect IMA from the chest wall, which was useful to shorten the operative time. In conclusion, arterial grafts, such as IMA and GEA were thought to be excellent coronary bypass conduits even for the small Japanese patient.

Adult↗