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Biomedical subjects

H Tatsukawa

Publications and source records attributed to H Tatsukawa.

At least 37 records · Page 2Linked to original sources
PubMed1992

[Regional myocardial coronary blood flow reserve in hypertrophic cardiomyopathy assessed by digital subtraction coronary angiography].

Using digital subtraction coronary angiography (DSA), we evaluated the regional myocardial coronary blood flow reserve (rMFR) in 18 patients with hypertrophic cardiomyopathy (HCM). There were 13 patients with asymmetrical septal hypertrophy (ASH), and 5 with asymmetrical apical hypertrophy (AAH). Eight subjects without apparent cardiac abnormality served as controls. Relations between the rMFR and regional wall thickness as determined by echocardiography were also investigated. Peak contrast density (Cm) and time to Cm (Tm) were measured from digital angiograms at the middle and distal ventricular septum (VS) and at the apical and left ventricular posterior wall (PW). The rMFR of each region of interest was expressed as the ratio of Cm/Tm at the baseline and at peak hyperemic response induced by intracoronary administration of papaverine. The rMFR was significantly lower at the VS and apex in HCM than in controls: middle VS, 1.9 +/- 0.5 vs 3.9 +/- 0.5, p < 0.001; distal VS, 2.0 +/- 0.5 vs 4.4 +/- 0.9, p < 0.001; and the apex, 2.0 +/- 0.7 vs 4.5 +/- 1.6, p < 0.01. However, it did not differ at the PW; 2.6 +/- 0.9 vs 3.0 +/- 0.9 between the 3 groups. The middle VS and apex, where the wall was the thickest, had the lowest rMFR in ASH and AAH. Furthermore, at the VS and apex, a curvilinear relationship was observed between the rMFR and wall thickness (rMFR = -0.88 in WT + 2.39, r = -0.57, p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Effect of cardiac sympathetic nerve stimulation on acutely ischemic myocardium--a comparison with the response to exogenous noradrenaline.

To assess the integrity of an adrenergic nervous function in acute myocardial ischemia, the contractile response of the ischemic region to cardiac sympathetic nervous stimulation (CSNS) was measured in comparison that with to exogenous noradrenaline (NA) infusion. In 13 anesthetized open chest mongrel dogs, haemodynamic changes, segmental wall motion, and the concentration of NA in the efferent coronary vein were measured. CSNS was performed by electrically stimulating the left ansa subclavia. Data concerning baseline values, values during CSNS, and those obtained during NA infusion both before and up to 5 h after coronary occlusion were compared. Regional myocardial blood flow of the ischemic region was also measured using the H+ clearance method. Systolic expansion with coronary occlusion was not changed or augmented by CSNS. However, improvement was observed in all experiments when NA infusion was used. The percent change of systolic shortening, indicating the response of segmental wall motion to CSNS, decreased soon after occlusion, recovered temporarily within 30 min after occlusion, but did not improve throughout the period after 60 min. The decrease of NA overflow into the efferent vein by CSNS showed a biphasic pattern; reduction occurring immediately after occlusion and again 3-5h after occlusion. Throughout these experimental studies it was considered that the preserved responses to the exogenous injected NA represented the contribution of presynaptic factor.

Animals↗
PubMed1991

Quantitative measurements of balloon-to-artery ratios in coronary angioplasty.

To determine the optimal balloon-to-artery ratio in percutaneous transluminal coronary angioplasty (PTCA), the effects of balloon size on the extent of residual stenosis, the incidence of coronary dissection, and the percentage of cases requiring repeat PTCA for restenosis were examined retrospectively. Fifty consecutive patients who underwent elective PTCA for simple and discrete lesion localized in the left anterior descending coronary artery were selected for this study. To measure the absolute cross-sectional area of the adjacent control segment of the artery, we developed a new method of quantitative coronary angiography, a hybrid of cinevideodensitometry and the edge detection method. The balloon-to-artery ratio was calculated as the cross-sectional area ratio between the control segment adjacent to the stenosis and the balloon which was visually selected by the operator during PTCA. Residual stenosis was determined as the percent area of stenosis by our hybrid method using cinevideodensitometry. The balloon-to-artery ratio ranged from 0.4 to 2.4, and a weak but significant inverse correlation (r = -0.51) was observed between the balloon-to-artery ratio and the extent of residual stenosis. In 23 patients whose balloon-to-artery ratios were less than 1.0, residual stenosis was greater (59.9 +/- 11.9% vs 46.0 +/- 19.6%, p < 0.05), and the percentage of repeat PTCA was higher (26% vs 4%, p < 0.05) than in the group of 27 patients whose balloon-to-artery ratios were higher than 1.0. The incidence of coronary dissection was similar in the 2 groups (9% vs 15%, ns). The percent area of stenosis before PTCA, the number of inflations, the inflation pressures, and the inflation times were also similar between these 2 groups. We concluded that the optimal balloon size is slightly more than the control segment dimensions of simple and discrete isolated stenoses of the left anterior descending artery treated at lower inflation pressures, and that an accurate measurement method of the coronary arterial dimensions is necessary to determine this optimal balloon size.

Angioplasty, Balloon, Coronary↗
PubMed1991

[A prominent retrograde flow in coronary artery in patients with hypertrophic cardiomyopathy].

Pathophysiology and clinical significance of a systolic backward flow in the epicardial coronary artery have not been elucidated. Using a 20 MHz Doppler catheter, we assessed coronary flow velocity waveforms in the left anterior descending coronary artery in 19 patients with hypertrophic cardiomyopathy (HCM) and 11 patients without apparent cardiac abnormalities as control subjects. Systolic flow fraction was smaller in HCM than in controls. Only 4 patients with HCM showed a prominent retrograde flow persisting during almost the entire systole. All the 4 had marked cavity obliteration and two of them had systolic intraventricular pressure gradients of 80 and 110 mmHg respectively. Exercise thallium-201 ECT revealed that myocardial hypoperfusion was more frequent in those 4 patients. Through these observations, it is concluded that a high intramyocardial systolic pressure combined with a relatively low coronary perfusing pressure may result in a large systolic retrograde flow in the left epicardial coronary artery, and that it may be related to myocardial ischemia in patients with HCM.

Adult↗
PubMed1991

[Evaluation of coronary arterial stenosis before and after PTCA: visual estimation versus computer-assisted analysis].

Coronary arteriogram of 34 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) were evaluated visually and by computer-assisted analysis, that employed an edge detection method and cine-videodensitometry. The results of visual estimation were in general agreement with those of computer-assisted analysis for determination of percent area of stenosis in severe stenosis, and percent diameter of stenosis in slightly stenotic lesions. Before PTCA, the findings obtained by densitometry agreed with those using the edge detection method. However, after PTCA, the results were significantly different. This discrepancy may have been due to asymmetric morphologic changes in the luminal cross sectional area immediately after PTCA, which could not be assessed by the edge detection method in a single-plane view. Through these studies it was concluded that the densitometry is most useful for evaluating the effects of PTCA.

Absorptiometry, Photon↗
PubMed1990

[Regional myocardial coronary blood flow reserve in hypertrophic cardiomyopathy assessed by digital subtraction coronary angiography].

Previous observations suggest the presence of ischemia in the disproportionately thickened interventricular septum (IVS) of patients with hypertrophic cardiomyopathy (HCM), although the details remain obscure. Utilizing digital subtraction coronary angiography (DSA) with LAO projection before and after intracoronary papaverine (P) injection, we evaluated regional myocardial coronary blood flow reserve (rMFR) consecutively 18 patients with HCM, and compared it with that of 8 patients without apparent cardiac abnormality (C). Time-density curves were obtained from digital angiograms of the myocardial region of interest. We measured peak contrast density (Cm) and time to peak contrast (Tm). An index of rMFR was calculated as the quotient of Cm/Tm before and after P. In HCM, rMFR in IVS and apex was significantly lower than that of C (Mid-IVS: 1.9 +/- 0.5 vs 3.9 +/- 0.5, p less than 0.001; Low-IVS: 2.0 +/- 0.5 vs 4.4 +/- 0.9, p less than 0.001; Apex: 2.0 +/- 0.7 vs 4.5 +/- 1.6, p less than 0.01). There was correlation between the impairment of rMFR and the extent of hypertrophy in HCM. In conclusion, we could state that, in HCM, the region of impaired myocardial coronary blood flow reserve is localized. In HCM, DSA is useful in evaluating myocardial coronary blood flow reserve.

Adult↗
PubMed1990

[Different sensitivity of sinus node and atrioventricular node to adenosine triphosphate].

We showed that higher concentration of adenosine 5'-triphosphate (ATP) was required to prolong the spontaneous cycle length of the sinus node (SN) than that required to prolong the spontaneous cycle length of the atrioventricular node (AVN). Spontaneously beating preparations of SN and AVN of rabbit (n = 8) were superfused with Tyrode solution containing 10(-8)-10(-3)M ATP, and action potential was recorded. The negative chronotropic action of ATP was dependent on the concentration. The required concentration of ATP to prolong spontaneous cycle length significantly (p less than 0.01) was 10(-5)M in SN and 10(-6)M in AVN, respectively. At concentrations higher than 10(-6)M, the degree of prolongation was greater in AVN than in SN (p less than 0.01). 10(-7)M dipyridamole enhanced this effect of ATP, while 10(-4)M theophylline reduced it. Action potential duration of 50% repolarization was not changed significantly in either SN or AVN at concentrations up to 10(-3)M. Maximum diastolic potential (MDP) was hyperpolarized from 10(-8)M to 10(-4) M. Hyperpolarization of MDP induced by ATP was greater in AVN than in SN but it was not statistically significant. MDP was depolarized by 10(-3) M ATP in both SN and AVN. The maximum velocity of depolarization was slightly larger in both SN and AVN as the concentration of ATP was increased in the perfusate. However, it was not statistically significant. 10(-3) M ATP decreased the maximum velocity of depolarization.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1989

Giant right atrial thrombus in Noonan syndrome combined with Eisenmenger's complex.

A 54-year-old woman with the Noonan syndrome was admitted with congestive heart failure and a giant right atrial thrombus with atrial septal defect detected by two-dimensional echocardiography. The thrombus vanished on oral anticoagulant therapy with warfarin. The thrombus is considered to result from hemostasis in the right atrium due to congestive heart failure and to her specific skeletal characteristics. This report describes the first case of Noonan syndrome with right atrial thrombus.

Echocardiography↗
PubMed1989

Cinevideodensitometric quantification of relative coronary arterial stenosis: application to evaluating candidates for percutaneous transluminal coronary angioplasty.

As an alternative to visual interpretations of subjects' angiograms, coronary arteries dilated by percutaneous transluminal coronary angioplasty (PTCA) were evaluated using cinevideodensitometry, and the results were compared with those obtained by the edge detection method. Coronary arteriograms were obtained in various projections and suitable frames were selected for analysis. The frames were transformed to digitized images (512 X 512 X 8 bits) with an image analyzer (MIPRON 1), and cinevideodensitometric and edge detection analyses were performed. Phantom models of various shapes were opacified with contrast medium and were used to test our system. The cineangiograms of 58 patients with ischemic heart disease, 28 of whom had underwent PTCA, were analyzed. A highly linear correlation was observed between the cross-sectional areas of the phantoms and the summed gray levels measured using cinevideodensitometry. Percent area stenosis evaluated by the two methods was accurate and reproducible in measuring the symmetrical stenosis models. However, for the model of asymmetrical stenosis, the measurement by the edge detection method differed according to various projections. Similar results were obtained measuring asymmetrical stenosis in the right coronary artery in vivo in various projections. Based on these experimental results, coronary stenoses dilated by PTCA were evaluated. Prior to PTCA, coronary arterial stenosis measured using the two methods closely approximated each other. However, following PTCA, there were discrepancies between the measurements by the two methods in six cases. This can be accounted for by asymmetrical changes in a luminal cross-section, which cannot be accurately assessed using the edge detection method in single plane projection. In conclusion, cinevideodensitometric measurements of relative coronary arterial stenosis were objective, accurate, and reproducible. According to cinevideodensitometric analysis, eccentric lesions can be measured using a single projection, and tracing arterial borders is unnecessary. It is a useful means in measuring quantitatively the degree of dilatation of coronary arterial stenosis accomplished by PTCA.

Angiography↗
PubMed1989

[Ultrasonic tissue characterization by spectral analysis of myocardial textural pattern].

Based on the fact that ultrasonic myocardial textural patterns are more irregular in the pathological myocardium than in the normal, evaluation of the myocardial tissue character was attempted in vivo using spectral analysis. Parasternal left ventricular long-axis echocardiograms were obtained from five patients with old myocardial infarction diagnosed by history, electrocardiography and coronary angiography. These echocardiograms were transferred to an image analyzer and digitized (256 x 256 x 8). The waveforms of the gray-scale-changes from the normal myocardium showed periodicity in each 8-pixel cycle, but those from the infarcted myocardium did not. To quantify pattern changes in gray-scale values in the ultrasound beam direction, spectral analysis was performed by the maximum entropy method (MEM). There were four peaks in the MEM spectra both in the normal and infarcted myocardia, but there was a great significance in these patterns: with high, steep peaks in normal MEM spectra, and low, blunt peaks in infarcted ones. By discriminatory analysis of these four peak values, normalized by the whole spatial frequencies as multivariate, the misclassification rate was 4.8-22.7% in anteroseptal infarctions and 5.0-20.0% in posterior infarctions. Thus, spectral analysis of the myocardial textural pattern has advantages for analyzing routine echocardiograms without corrections by any absolute ultrasonic references. Furthermore, the misclassification rate is so low that we are able to characterize myocardial tissue.

Echocardiography↗
PubMed1989

[Evaluation of right ventricular systolic and diastolic properties using 81mKr scintigraphy with continuous infusion].

To evaluate right ventricular (RV) systolic and diastolic properties in patients with various heart diseases, RV volume curves obtained from 81mKr scintigraphy with continuous infusion were analyzed. The data were acquired in right anterior oblique position for five minutes, and from RV time activity curve and its first derivative curve, ejection fraction and peak ejection rate as systolic indices, and peak filling rate, time to peak filling and 1/3 mean normalized diastolic filling rate as diastolic indices were calculated. Ejection fraction in patients with dilated cardiomyopathy was lower than that in controls, but there was no difference in systolic indices among controls and patients with the other heart diseases. However, diastolic indices in patients with hypertrophic cardiomyopathy, patients with hypertensive heart disease, patients with dilated cardiomyopathy, patients with inferior myocardial infarction, and some patients with anteroseptal myocardial infarction were lower than those in controls. In conclusion, analysis of RV time activity curve by 81mKr scintigraphy with continuous infusion provides RV systolic and diastolic indices, which may permit evaluation of RV systolic and diastolic properties in various heart diseases.

Female↗
PubMed1981

In vitro growth of Mycobacterium lepraemurium under the influence of macrophage cultures.

Elongation and limited multiplication of Mycobacterium lepraemurium was observed extracellularly when the bacilli spotted on a coverslip were placed face to face with cultures of mouse peritoneal macrophages adhering to the inside of a test tube held at an angle of 15 degree. There was no doubt that certain growth-promoting but unstable factors were released from the macrophages.

Culture Media↗