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Biomedical subjects

Y Morikawa

Publications and source records attributed to Y Morikawa.

At least 253 records · Page 14Linked to original sources
PubMed1988

[Transmitral blood flow velocity patterns evaluated by pulsed Doppler echocardiography in diagnosing transient myocardial ischemia].

To evaluate the influences of transient myocardial ischemia on transmitral blood flow velocity patterns, pulsed Doppler echocardiography was performed during coronary artery occlusion in 10 anesthetized open-chest dogs, and also during esophageal pacing or the administration of dipyridamole in 79 patients with coronary artery disease (CAD), and in 19 control subjects. During occlusion of the coronary artery, an abrupt decrease in the peak velocity of the rapid filling wave (R) was noted within one min simultaneously with rapid decrease of % wall thickening in the ischemic regions. The peak velocity of atrial filling was augmented compensatorily. Although the transmitral blood flow velocity pattern did not change in the controls with esophageal pacing, changes similar to those which were obtained during experimental studies were demonstrated in CAD patients. There were no significant differences between transmitral blood flow velocity patterns of patients with multivessel disease and those with single vessel disease. Ischemic changes in transmitral blood flow velocity patterns were not demonstrated in patients with mitral regurgitation. Sublingual nitroglycerin normalized post-pacing abnormal blood flow velocity patterns. In contrast, after the intravenous administration of 0.56 mg/kg of dipyridamole, R and A were increased and the A/R ratio was unchanged both in CAD patients and the control groups. Deceleration time, or the half time, was prolonged during both provocation tests in CAD patients, and these changes were transient and were restored within several min. Furthermore, they were noted more frequently than was the development of ST depression on ECG, or chest pain. These findings indicate that the transmitral blood flow velocity patterns obtained by pulsed Doppler echocardiography are useful for detecting transient myocardial ischemia, though they have limitations in diagnosing the extent of coronary artery disease.

Animals↗
PubMed1988

[Value of exercise echocardiography in evaluating left ventricular systolic function in mitral stenosis].

Exercise echocardiography was performed for 34 patients with mitral stenosis (MS) to evaluate left ventricular (LV) systolic function. The patients were categorized in three groups according to the work loads attained: Group I, 14 patients who attained 25 watts; Group II, 10 patients, 50 watts; and Group III, 10 patients, 75 watts. Among these groups, there were no statistical differences between the resting echocardiographic LV systolic function and their cardiac catheterization data. Resting LV end-diastolic and end-systolic dimensions (EDD and ESD) did not differ by group. During exercise, EDD and ESD decreased significantly in all groups, but ESD at the maximum exercise in Group I was greater than those of the other groups. The percent fractional shortening of the left ventricle (%FS) decreased significantly with exercise in Group I, while it increased significantly in the other groups. The mean velocity of circumferential fiber shortening (mean Vcf) increased significantly in all groups, but the extent was least in Group I. The exercise-induced changes in %FS (delta %FS) and mean Vcf (delta mean Vcf) correlated closely with exercise duration (r = 0.80, r = 0.73), but this was not the case in the mitral valve area. Postoperatively, exercise echocardiography was also performed for 14 patients with mitral stenosis; two of seven patients in Group I, four of five in Group II, and two in Group III showed significant improvement in exercise tolerance after surgery. However, the other six patients showed no change in their exercise tolerance. The former patients had positive values in delta %FS and more than 0.5 circ/sec in delta mean Vcf during pre-operative evaluations, while except one patient, those who did not improve had negative delta %FS values and less than 0.5 circ/sec in delta mean Vcf. It was concluded that the change in LV systolic function during exercise echocardiography reflects LV functional reserve in patients with MS, and provides valuable information for evaluating the severity of, indications for and benefits from surgery for MS.

Blood Pressure↗
PubMed1987

Developmental changes in the effects of lidocaine and quinidine on the canine heart.

We studied the developmental changes that occur in the use-dependent effects of lidocaine and quinidine on the intact canine heart. At comparable intravenous dosages, adults showed higher total and free plasma lidocaine concentrations than young dogs, whereas for quinidine, the total and free levels were comparable. Lidocaine demonstrated a use-dependent depressant effect on intraventricular conduction in adults that was significantly greater than that in the young, and it significantly accelerated repolarization (QT interval) in the adult. In contrast, comparable effects of quinidine were seen on conduction in adult and young dogs, while repolarization was prolonged more in the young. These effects on conduction and repolarization in the adult and young hearts were explained by our earlier cellular electrophysiologic studies. Our findings indicate the following: (a) developmental changes in the cellular electrophysiologic effects of specific antiarrhythmic drugs are predictive of the effects in the in situ heart; (b) these effects are further modified by developmental differences in drug metabolism and protein binding; (c) developmental changes in the effects of one antiarrhythmic local anesthetic are not necessarily predictive of those for another; and (d) the effects of drugs on the adult heart may be, but are not necessarily, predictive of those in the young.

Aging↗
PubMed1987

Developmental changes in the response of cardiac Purkinje fibers to SC-72-14.

We used standard microelectrode techniques to study the effects of SC-72-14, a monoclonal antibody to eel electroplax, and tetrodotoxin (TTX) on the electrophysiological properties of neonatal and adult canine Purkinje fibers. SC-72-14, 7 ng/ml, depressed maximum upstroke potential (Vmax) and membrane responsiveness of adult but not neonatal fibers. In contrast, we previously had shown TTX to have a greater effect on neonatal than adult fibers (29). Even in the presence of SC-72-14, TTX continued to have a greater effect on the neonatal fibers. The effects of TTX and SC-72-14 were cumulative over the concentration range studied, and our results are consistent with their acting at different sites.

Action Potentials↗
PubMed1987

[Effects of magnesium deficiency on dermal mast cells in rats].

The effects of dietary magnesium (Mg) deficiency on dermal mast cells were studied in young Wistar rats weighing about 50 g. The rats fed with a Mg-deficient diet (0.001% Mg) showed hyperemia on the 3rd or the 4th day after they were fed the diet. The dermal mast cells of the control rats were filled with granules, while the cells of rats fed the Mg-deficient diet for 4 days contained less granules than the controls, but contained extensively dilated rough surfaced endoplasmic reticulum, well-developed Golgi complexes, many mitochondria and ribosomes. These data suggest that hypomagnesemia could induce a release of histamine from dermal mast cells. So, the effect of a low Mg medium on the release of histamine was studied using peritoneal mast cells in vitro. A low Mg medium (0.2 mM Mg) induced much more histamine release than control medium (1 mM Mg) from the peritoneal mast cells obtained from both control and Mg-deficient rats fed with the Mg-deficient diet for 2 days. The peritoneal mast cells obtained on the 8th day of Mg-deficiency released much more histamine than controls in 1 mM Mg medium. These results suggest that hyperemia observed in Mg-deficient rats depends partly on histamine released from dermal mast cells.

Animals↗
PubMed1987

[Studies on histamine containing cells in the spleen of the magnesium-deficient rats].

When young Wistar rats (body wt. 50 g) were maintained on a magnesium-deficient diet (0.001% Mg) for eight days, the splenic weight and histamine content increased about 2-fold and 30-fold, respectively, compared with those of the control rats. There was no significant difference in the number of splenic mast cells between the magnesium-deficient and control rats. More neutrophilic, eosinophilic and basophilic granular cells were found in the spleen cells isolated from the magnesium-deficient rats than in those from the control rats. Of the isolated cells from magnesium-deficient rats, 7.6% were basophilic granular cells; however, no basophilic granular cells were observed in the spleen cells isolated from the control rats. In the cytochemical study, the yellowish fluorochrome formed by the interaction of o-phthalaldehyde and histamine was found in basophilic granular cells. These results suggest that the increase in the histamine content of the spleen of magnesium-deficient rats is related to the increased number of basophilic granular cells.

Animals↗
PubMed1987

[Transmitral flow patterns during acute coronary artery occlusion: experimental and clinical evaluations by pulsed Doppler echocardiography].

To evaluate left ventricular diastolic properties during acute myocardial ischemia, transmitral flow patterns were analyzed by two-dimensional pulsed Doppler echocardiography. In a preliminary study of transient coronary artery occlusion in anesthetized open-chest dogs, the following results were obtained: decreased peak velocity of rapid filling, prolonged rapid filling period, and compensatory increase in the peak velocity of atrial filling. These changes occurred nearly concomitantly with decreased cardiac output, elevated left atrial and left ventricular end-diastolic pressures, and decreased left ventricular systolic pressures. With reperfusion of the coronary artery, these parameters rapidly returned to the base line values. In acute and transient myocardial ischemia induced by intracoronary balloon inflation during therapeutic percutaneous transluminal coronary angioplasty (PTCA) in man, similar changes in these parameters were observed, and the changes were more marked in PTCA for the left anterior descending artery as compared with that of the right coronary artery. In conclusion, noninvasive two-dimensional pulsed Doppler echocardiography is of practical use in evaluating deterioration of the diastolic function of the left ventricle during acute and transient myocardial ischemia.

Angioplasty, Balloon↗
PubMed1987

[Clinical utility of spatial color mapping vectorcardiography in diagnosing myocardial infarction: comparison with 201Tl scintigraphy].

The feasibility of spatial color mapping vectorcardiography in diagnosing the site and extent of the old myocardial infarct was evaluated in comparison with 201T1 scintigraphy. Vectorcardiographic data made by Frank's technique were entered in the personal computer and the QRS complexes were plotted over 112 points crossing the latitude of each 20 (from 20N to 80S) degrees and longitude of each 20 degrees from 20W to 20E on the spherical body. Eight colors were assigned according to the direction of the QRS vector. To construct a territorial map, the apical, then, the septal, anterior, lateral, inferior and posterior portions were determined from the normal 201Tl scintigrams. Myocardial images obtained in the anterior, left anterior oblique and lateral projections were analyzed by the circumferential profile curve. Diagnostic specificity for infarction was greater than 60%, and especially high (90%) in the anterior, apical and lateral regions, but relatively low (50%) in the septal, inferior and posterior regions. Accuracies exceeded 64%. The infarcted areas assessed by spatial color vectorcardiography agreed with those assessed by 201T1 myocardial scintigraphy. Thus, spatial color vectorcardiography was simple and useful for diagnosing the site and extent of myocardial infarction.

Adult↗
PubMed1987

Induction of lymphokine-activated killer activities in peripheral blood lymphocytes and regional lymph node lymphocytes against PC-9 cultured adenocarcinoma and autologous pulmonary adenocarcinoma cells.

The cytotoxic activities, of the peripheral blood lymphocytes (PBL) and regional lymph node lymphocytes (LNL) generated by incubation with recombinant IL-2 (rIL-2) in vitro, have been studied to assess their effects on autologous pulmonary adenocarcinoma cells from 21 patients with lung cancer. The lymphokine-activated killer (LAK) activities of PBL were 22.9 +/- 14.8% for autologous pulmonary adenocarcinoma cells and 44.9 +/- 20% for PC-9 cells. A previous coculture of autologous tumor cells with PBL (ATS-LAK) showed no increase in induction of cytotoxicity to autologous tumor cells. The LAK activities of LNL were significantly lower than those of PBL. The cytotoxicities of rIL-2 activated lymphocytes seemed lower in well differentiated pulmonary adenocarcinoma than in moderately and poorly differentiated adenocarcinoma, and higher in patients with lymph node metastasis than in those without; they appeared, however, not to be related to clinical stage or degree of infiltration of T-zone histiocytes into the cancer stroma. The cytotoxicity to autologous tumor cells was not significantly different in the presence of the Ia antigen expressed on tumor cells, but the cytotoxicity to Ia positive PC-9 cells was significantly higher for rIL-2 activated lymphocytes from patients with lung cancer cells which were Ia positive than from those where they were Ia negative. The presence of Ia antigen on tumor cells seemed important for antitumor activity.

Adenocarcinoma↗
PubMed1987

[Study on effectiveness of carmofur (Mifurol) in urogenital carcinoma, especially bladder cancer, as a post-operative adjuvant chemotherapeutic agent].

This study was carried out to evaluate the effects of carmofur (Mifurol), a masked compound of 5-fluorouracil (5-FU), in preventing postoperative recurrence of urogenital carcinoma (especially in bladder cancer). Carmofur was given orally at the dose of 300 approximately 600 mg/day to 134 patients (90 males and 44 females) after the resection. Out of 134 patients, 121 patients were evaluable and the rate of their recurrence was 10.7%. The rate of cumulative nonrecurrence for 65 patients it was 96.0, 73.0 and 60.8% in 1, 2 and 3 years, respectively. The group of curative resection demonstrated a higher cumulative nonrecurrence rate than that of noncurative or palliative resection group. In considering the resection methods, transurethral resection of bladder tumor group demonstrated a higher rate than partial or total cystectomy. The average concentration of 5-FU in serum was 0.65 microgram/ml at 120 minutes after oral administration of 200 mg of carmofur. Moreover, the concentration of 5-FU (15 approximately 35 micrograms/ml) in urine was higher than that of carmofur. The rate of side effects that appeared was 19.6%. The side effects were hot feeling (12.2%), pollakisuria (4.3%), anorexia (4.3%), an antabuse-like reaction by drinking (3.8%) and so on. These results were similar to those already reported.

Administration, Oral↗