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Biomedical subjects

M Mishima

Publications and source records attributed to M Mishima.

At least 181 records · Page 10Linked to original sources
PubMed1988

Effect of OPC-8212 (2(1H)-quinolinone), a new inotropic agent, on myocardial energy metabolism in patients with coronary heart disease.

We examined the effects of a new inotrope, OPC-8212 (OPC: 2(1H)-quinolinone), on coronary sinus flow (CSF), myocardial oxygen consumption, myocardial lactate extraction ratio (LER), cardiac index (CI) and pulmonary arterial diastolic pressure (PADP) in eleven patients with prior myocardial infarction. Measurements were taken before (control) and 8 hours after administration of OPC (480 mg, p.o.). A cardiac function curve was obtained in each stage with rapid intravenous administration of 500 ml of saline (loaded state) after baseline measurements. There was a significant increase in the cardiac index and decrease in the pulmonary arterial diastolic pressure in the loaded state after OPC. Thus the ventricular function curve was shifted to the left and showed a steep incline, indicating an increased inotropic state. On the other hand, myocardial oxygen consumption and myocardial lactate extraction ratio were unchanged. Thus we concluded that OPC improved cardiac performance without increasing myocardial oxygen consumption.

Adult↗
PubMed1988

[Regional myocardial perfusion in ischemic heart disease assessed by myocardial contrast echocardiography].

Myocardial contrast echocardiography is a new cardiovascular imaging technique that can be used to evaluate regional myocardial perfusion. Regional myocardial perfusion was studied in 12 patients with normal coronary arteries, 14 patients with old myocardial infarction, four patients with acute myocardial infarction, and 15 patients with effort angina. Conventional two-dimensional echo imaging was obtained during intracoronary injections of relatively small volumes (2 ml) of agitated Urografin-76. The echo intensities were measured before and after injecting contrast agents and the subtraction images were composed by a high-speed image processor (NEXUS 6400). Clear myocardial images were obtained in 10 of 12 the patients with normal coronary arteries, and they reflected well the epicardial arterial architecture by coronary angiography. In cases of old myocardial infarction, the infarcted areas appeared as contrast defects in seven and as slightly enhanced areas in three of the 10 patients. In cases of acute myocardial infarction, contrast defect areas in the myocardial images were less in two cases of successful early coronary thrombolysis or percutaneous transluminal coronary angioplasty (PTCA). However, contrast defects remained unchanged despite good recanalization in one case of delayed PTCA. In cases of effort angina, anginal attacks were successfully induced by rapid atrial pacing in six of the 15 patients. In four of the six patients, contrast enhancement in myocardial imaging during anginal attack decreased more in the endocardial than in the epicardial myocardium, possibly reflecting subendocardial ischemia. It is concluded that this technique can identify regional myocardial perfusion, which is not revealed by coronary angiography, and it is therefore useful for the clinical analysis of ischemic heart disease.

Angina Pectoris↗
PubMed1987

Evaluation of orally administered activated charcoal on intestinal dialysis of intravenously administered M79175, an aldose reductase inhibitor, in rats.

The effect of oral administration of activated charcoal on serum elimination of 14C-M79175 injected intravenously in rats was studied. In situ single-pass perfusion studies showed that M79175 and/or its metabolites was transported into the small intestinal lumen. Total radioactivity expressed as equivalents of M79175 exsorbed in the perfusate and excreted in the bile juice was 3.2% and 2.0%, respectively, of dose. Oral administration of multiple doses of activated charcoal significantly decreased the serum concentration and serum half-life of 14C-M79175. The fecal excretion of 14C-M79175 after treatment with activated charcoal was increased when compared to that in the control. On the other hand, urinary excretion of 14C-M79175 after treatment with activated charcoal was decreased. However, there was no significant difference in the cumulative amounts of total excretion (fecal plus urinary excretion) between rats with activated charcoal treatment and rats without charcoal treatment. These results suggest that intestinal dialysis by oral activated charcoal is a reasonable method to enhance the elimination of M79175 from the serum in case of overdose of the drug.

Administration, Oral↗
PubMed1987

Studies on the promoting effects of medium chain fatty acid salts on the nasal absorption of insulin in rats.

We investigated the promoting effect of medium chain fatty acid salts such as sodium caprylate, sodium caprate (Na C10) and sodium laurate on rat nasal absorption of insulin. Further, we studied the possible mechanism of the absorption promoting effect by fatty acid salts in terms of hemolytic activity, osmotic pressure, chelating effect and inhibition of leucine aminopeptidase activity. Na C10 exhibited the strongest absorption promoting effect on insulin among these fatty acid salts. The promoting effect of Na C10 was very rapid reaching the maximum immunoreactive insulin level within 5 min and its optimum concentration was about 1%. The amount of insulin absorbed after a nasal administration with Na C10 was about 98% of one half subcutaneous dose. The absorption promoting effect of fatty acid salts on insulin was at least in part associated with the chelating ability for calcium ions and the inhibitory action on leucine aminopeptidase activity.

Absorption↗
PubMed1986

Clinical assessment of elastic properties of large coronary arteries: pressure-diameter relationship and dynamic incremental elastic modulus.

Vascular elastic properties in vivo (dynamic incremental elastic modulus [Ep(dyn)]) of large coronary arteries were assessed from the pressure-diameter relationships of the large coronary arteries in 46 patients with suspected ischemic heart disease. Ep(dyn) represents the vascular stiffness primarily determined by the organic sclerotic changes of the vascular wall and the vascular smooth muscle tone. Coronary arterial diameter was obtained from the magnified cine coronary arteriograms by using a computerized caliber measurement technique. The mean Ep(dyn) of the left main coronary artery and the proximal portions of the left anterior descending and circumflex coronary arteries with apparently normal angiograms were significantly (P less than 0.01) increased as the number of involved coronary vessels was increased. Mean Ep(dyn) values in multi-vessel disease were comparable with those of dilated segment by the percutaneous transluminal coronary angioplasty, indicating that the vascular sclerotic changes are not localized to the narrowed segments but diffusely distributed to the angiographically normal vascular wall. In 4 patients who had successful percutaneous transluminal coronary angioplasty, Ep(dyn) of the dilated coronary segment showed markedly higher values (0.21-0.30 X 10(6) Nm-2) than the normal values (0.16 +/- 0.06 X 10(6) Nm-2 in left anterior descending coronary artery). In contrast, there was no significant difference in Ep(dyn) values of the angiographically normal left main coronary trunk, proximal portions of left anterior descending and circumflex arteries between patients with and without vasospastic angina. During myocardial ischemia induced by ergonovine maleate, vasospastic response of the non-diseased segment was comparable with that in patients who did not have an anginal attack during the ergonovine test. Thus, in contrast to the sclerotic change, abnormal vasoconstrictive property of the coronary artery may be localized to the diseased segment.

Adult↗
PubMed1986

Changes in frontal lobe size with age. A CT study in children.

A series of linear measurements on computed tomography of the brain was performed in 481 children (from newborns up to 5 years of age). Each measurement increased with age in infancy and early childhood. In addition to the commonly used linear measurements, a new index has been devised. This index equals the ratio between the sagittal diameter of the brain and the sagittal midline distance from the anterior border of the brain to a line tangential to the anterior horns. All measurements were made on the scan at the level of the foramen of Monro. This index was called the frontal force index (FFI), because it seemed to reflect the morphologic change in the frontal lobes. The functions related to the frontal lobes, i.e. cognitive functions, develop rapidly during infancy and early childhood. In normally or subnormally developed children the FFI increased during early infancy and decreased in severely retarded children. The FFI is obviously useful in the evaluation of the development of the frontal lobes.

Child, Preschool↗
PubMed1986

The bifrontal fluid collection area and other cerebrospinal fluid spaces at computed tomography in children. Its variations with increasing age and pathologic conditions.

A total of 592 computed tomography examinations of the brain in children were studied from the aspect of age and development. The series was divided into 3 groups with respect to neurologic development: 1) normal without neurologic symptoms, 2) normal or subnormal with neurologic symptoms, and 3) moderately to severely retarded. For evaluation, a method of visual grading was applied for each cerebrospinal fluid space. Concerning the ventricular system, the most significant changes in size with increasing age were noted in the lateral ventricles. There were no significant changes in the third and fourth ventricles. Among the three groups, the enlargement was most prominent in group 3 and less prominent in groups 1 and 2. Concerning the extraventricular spaces, the enlarged bifrontal fluid collection area, the sylvian fissure, the interhemispheric fissure, and the cerebral sulci vanished with increasing age. Similarly to the ventricular system, the enlargement was most prominent in group 3, and less prominent in groups 1 and 2, above the age of 1 year. The relation of these results to age and developmental factors are discussed.

Adolescent↗
PubMed1986

[Collateral circulation during exercise-induced angina: evaluation by coronary angiography].

The pathophysiological significance of coronary collateral vessels remains controversial, despite previous intensive studies. We performed the multistage supine ergometer stress test for 26 patients with effort angina and collaterals. The changes in the collaterals were observed during each anginal attack by coronary angiography before and after intravenous nitroglycerin. The collaterals of 21 patients disappeared or diminished during exercise-induced angina before nitroglycerin administration, and were unchanged in the remaining five cases. However, the collaterals of all patients after nitroglycerin administration were unchanged or increased during exercise-induced angina. Considering there were no significant changes in pulmonary arterial end-diastolic pressures during angina before and after nitroglycerin administration, a pressure gradient between the donor and recipient coronary arteries was suggested as being related to the patency of the collaterals. These results suggested the following: 1. It is not appropriate to postulate that the collaterals visualized at rest may remain unchanged during exercise-induced angina. 2. It is not reasonable to conclude that exercise accelerates the development of collateral circulation. 3. One favorable effect of nitroglycerin administration is the prevention of exercise-induced ischemia via collateral circulation.

Adult↗
PubMed1985

Effects of three proteins on absorption of cadmium in rats.

The effects of 3 proteins on the gastrointestinal absorption of cadmium were studied. Glycinin and ovalbumin significantly decreased cadmium in liver and the total cadmium in the tissues of rats following a single oral administration of cadmium. In addition, in rats fed continuously with the experimental diets containing cadmium together with proteins, glycinin and ovalbumin significantly decreased the contents of cadmium in the tissues. These results show that the proteins depressed the gastrointestinal absorption of cadmium. Moreover, the effects of cadmium on various digestive enzymes for proteins and the pepsin or pepsin-pancreatin digestion of the proteins were examined. As a result it is likely that the inhibitory effect of cadmium on the intestinal digestion of these proteins is one of the causes of the inhibitory effects of the proteins on the intestinal absorption of cadmium in rats. The undigested oligopeptides may decrease the amount of free cadmium available to be absorbed from the intestine by binding cadmium itself, resulting in decreased intestinal absorption of cadmium.

Animals↗
PubMed1985

[Intracardiac flow dynamic alterations with a prosthetic mitral valve studied by pulsed Doppler technique].

Intracardiac flow dynamic alterations in patients (pts) with prosthetic mitral valve (PMV) were studied to assess prosthetic valve functions using pulsed Doppler technique and two-dimensional echocardiography. The study population consisted of 23 pts who underwent mitral valve replacement (11 with the Starr-Edwards disc valve, nine with the Björk-Shiley tilting disc valve, two with the Hancock porcine valve, and one with the homograft valve), 20 pts with mitral stenosis, and 17 control subjects (15 healthy persons and two with lone atrial fibrillation). All pts had a normal functioning PMV by clinical evaluation except for one patient with a dysfunctioning homograft valve, which was angiographically documented. Flow velocity patterns were obtained at various sites in the left ventricle (LV) and the left atrium (LA). Flow dynamic alterations in pts with PMV were evaluated from the half time of transmitral flow velocity descent in diastole, as an index of the atrioventricular pressure gradient, the extent of dispersion of Doppler frequency spectrum of intraventricular flow as an index of the degree of flow disturbances and the Doppler signals with broadening spectra indicating transvalvular regurgitant flow into the LA. The results were as follows: In pts with PMV, the velocity of transmitral flow decreased slowly and linearly throughout diastole. The half time was significantly prolonged for pts with PMV as compared with that for control subjects (272 + 94 ms [mean + SD] vs 79 + 15 ms, p less than .001), though it was shorter than that in pts with mitral stenosis (457 + 145 ms, p less than .001). In pts with PMV, the half time for pts with the Björk-Shiley valve was relatively short as compared with that for pts with other valve. Marked prolongation of the half time (483 ms) was observed in a patient with a dysfunctioning homograft valve. These findings indicate that any PMV is obstructive, even with normal valve function, as compared with healthy mitral valves and that the Björk-Shiley valve is superior to the other PMVs studied in regard to the pressure gradient across PMV. Diastolic flow velocity patterns in the LV were highly dependent on the type of PMV. Apparently, the flow characteristics in the LV were disturbed in every patient with PMV regardless of the type of PMV. The high pressure gradient across the PMV suggested by the prolonged half time in pts with PMV, may be partially caused by flow disturbances produced by PMV.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1984

[Non-invasive estimation of transmitral pressure gradient and mitral valve area in mitral stenosis by an ultrasonic pulsed Doppler technique].

We attempted to estimate transmitral pressure gradient and mitral valve area (MVA) noninvasively in mitral stenosis (MS) by a bi-directional pulsed Doppler flowmeter combined with an electronic two-dimensional echocardiograph. Eleven patients with MS in sinus rhythm were studied by cardiac catheterization. Fifteen healthy subjects (H) served as normal control. The pulsed Doppler flowmeter operated with a carrier frequency of 2.5 MHz, a pulse repetition rate of either 5 KHz or 10 KHz and a sample volume of 1 X 3 X 3 mm. The velocity of transmitral central flow was measured by this system, monitoring audible Doppler sounds and cardiac images which depict the anatomic location of the sampling site. The Doppler signal was analyzed by a sound spectrograph. In estimating the transmitral pressure gradient and MVA, we employed a Doppler parameter (half time) defined as the time for instantaneous maximal blood flow velocity to reduce to one-half from its rapid inflow peak, which is independent of the angle between the ultrasonic beam and blood flow. Transmitral pressure gradient (delta P100) was measured as the pressure gradient between either left atrial or pulmonary capillary pressure and left ventricular pressure at the point after 100 msec from the nadir of left ventricular early diastolic pressure [( LA or PC--LVDP]100). MVA was obtained using a Gorlin's formula. The transmitral blood flow velocity in both MS and healthy groups revealed a narrow frequency band pattern with two peaks, R and A, in diastole. The former peak occurred during rapid inflow phase and the latter following atrial contraction. In the healthy group, the descent rate of R wave was increased than that in the MS group. The square root of the pressure gradient also reduced linearly with transmitral flow velocity in the MS group. Thus in the MS group, the transmitral velocity was directly proportional to the square root of the pressure gradient as described by a Bernoulli theorem, and the half time was proportional to the transmitral velocity. The square of the half time (delta t2) was highly correlated with delta P100 (r = 0.97), and the inverse of the half time (delta t-1) was correlated with MVA (r = 0.76). There was no significant correlation between delta P100 and diastolic descent rate of anterior mitral leaflet (DDR). The present study indicates that the half time is useful in estimating transmitral pressure gradient and MVA in mitral stenosis.

Adult↗