PubMed Health⌕ Search

Biomedical subjects

H Emoto

Publications and source records attributed to H Emoto.

At least 37 records · Page 2Linked to original sources
PubMed1993

Effects of stent design and serum cholesterol level on the restenosis rate in atherosclerotic rabbits.

We investigated the effect of serum cholesterol level and stent design on the restenosis rate within the stent after balloon angioplasty and stent implantation using atherosclerotic rabbits. Two types of nickel/titanium stents with gaps (open stent) and without gaps (closed stent) between the wire coils were implanted into the aorta of the rabbits 10 weeks after atherosclerosis had been induced using a standard high cholesterol diet and balloon abrasion. Each rabbit had an open stent and a closed stent implanted into the infrarenal abdominal aorta. Between these two stents a control segment of the aorta was treated with angioplasty alone. The animals were divided into two groups according to the diet protocol as follows: in group I (n = 9) a high cholesterol diet was stopped after stent implantation; in group II (n = 10) a high cholesterol diet was maintained after stent implantation. Digital subtraction angiograms were obtained every 4 weeks for up to 24 weeks and the narrowest diameter of the arterial segments within each stent and in the segment between stents was measured. The diameter narrowing within the closed stent was greater in the high cholesterol group compared with the low cholesterol group: 12 weeks (2.57 +/- 0.09 mm in group I vs 2.14 +/- 0.15 mm in group II, mean +/- S.E., p < 0.05); 16 weeks (2.55 +/- 0.09 mm vs 2.14 +/- 0.12 mm, p < 0.05); 20 weeks (2.59 +/- 0.06 mm vs 1.98 +/- 0.12 mm, p < 0.01); and 24 weeks (2.45 +/- 0.11 mm vs 2.01 +/- 0.11 mm, p < 0.05). No significant differences in the narrowest diameter of the arterial segments were observed between high and low cholesterol groups in the angioplasty alone areas or within the open stents. There was a significant difference in the narrowest diameter between stents with versus those without gaps (at 12, 16, and 20 weeks poststenting in group I and at 4, 8, 12, 16, 20, and 24 weeks in group II). Thus the stent with the least metal is correlated with less stenosis and intimal hyperplasia. From these data we conclude that both stent design and serum cholesterol are important factors for restenosis after stent implantation.

Angioplasty, Balloon, Coronary↗
PubMed1993

Corticotropin-releasing factor activates the noradrenergic neuron system in the rat brain.

The effect of corticotropin-releasing factor (CRF) on central noradrenaline (NA) metabolism was examined by measuring levels of the major metabolite of NA, 3-methoxy-4-hydroxy-phenylethyleneglycol sulfate (MHPG-SO4) in several rat brain regions. Various doses of CRF ranging from 0.5-10 micrograms injected ICV significantly increased MHPG-SO4 levels in several brain regions including the hypothalamus, amygdala, midbrain, locus coeruleus (LC) region, and pons + medulla oblongata excluding the LC region. Plasma corticosterone levels were also significantly increased after ICV CRF administration up to 0.5 micrograms. The present results that CRF not only elevates plasma corticosterone levels but also increases NA metabolism in many brain regions suggest its neurotransmitter and/or neuromodulator role exerting the excitatory action on central NA neurons.

Animals↗
PubMed1993

[The effect of CRF antagonist on immobilization stress-induced increases in noradrenaline release in rat brain regions].

We investigated the effects of intracerebroventricular (i.c.v.) administration of corticotropin-releasing factor (CRF) antagonist, alpha-helical CRF9-41 (ahCRF) on stress-induced increases in noradrenaline (NA) release in rat brain regions. Pretreatment with ahCRF (50 or 100 micrograms) attenuated significantly the stress-induced increases in levels of 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO4), the major metabolite of NA in rat brain, in the locus coeruleus region, cerebral cortex, hippocampus, amygdala and hypothalamus. Plasma corticosterone levels were not decreased significantly by administration of ahCRF. From these results, it is suggested that stress-induced increases in NA release in the rat brain regions are attenuated by ahCRF and thus that CRF, released during the stress, cause increases in NA release in these regions.

Animals↗
PubMed1993

[Report of a case of the anomalous origin of the right coronary artery from the pulmonary artery with atrial fibrillation and bradycardia].

A 62-year-old man who was referred to implantation of pacemaker on account of severe bradycardia revealed anomalous origin of the right coronary artery from the pulmonary artery on aortography. The aortic root cineangiogram demonstrated single left coronary artery arising from the aorta with retrograde filling of the right coronary artery (RCA) which drained into the main pulmonary artery. Chest X-ray revealed marked cardiomegaly and treadmill exercise test shows positive at stage 2 of the Bruce protocol. Operation was performed under cardiopulmonary bypass. Although we tried to transplant the RCA to the aorta, the arterial wall was very fragile and could't bear arterial pressure. Therefore the RCA was ligated at its origin and disconnected from the pulmonary artery. Post operative course was uncomplicated and the patient was discharged without any symptoms.

Atrial Fibrillation↗
PubMed1992

Effects of design geometry of intravascular endoprostheses on stenosis rate in normal rabbits.

To investigate the effects of gaps between the individual wire coils of a shape memory Nitinol alloy intravascular endoprosthesis, 20 stents with and without gaps were implanted transluminally into the infrarenal abdominal aortas of 10 normal rabbits after balloon angioplasty. Digital subtraction angiography (DSA) was done at 4, 12, 16, 20, and 24 weeks after stent implantation to examine the stenosis rate and major side branch patency. Stenosis rate within stents with gaps were significantly lower than those without gaps: 8.1 +/- 5.0% versus 15.0 +/- 6.8% at 12 weeks, 13.6 +/- 6.0% versus 26.0 +/- 9.4% at 24 weeks by DSA, p greater than 0.005 and p less than 0.01 respectively. The maximum and mean neointimal thickness measured histologically at the time of animal death correlated significantly to the narrowest diameter obtained from the DSA studies, (r = 0.84 and r = 0.79, respectively, p less than 0.01). Greater hyperplasia of the neointima was evident in the stented arterial segments with stents without gaps compared with those with gaps (83 +/- 22 versus 187 +/- 46 microns mean thickness, p less than 0.001). The patency rate of the side branches in the stented arterial segment was significantly (p less than 0.05) higher in stents having gaps. These results suggest that the placement of gaps between wire pitches reduced the neointimal thickness within stents and prevented the obstruction of arterial side branches.

Angioplasty, Balloon↗
PubMed1992

Effects of angiotensin II on behavioral responses of defensive burying paradigm in rats.

The effects of angiotensin II (ATII) administered intracerebroventricularly in male Wistar rats in doses of 0.1, 0.5, and 1.0 micrograms, as well as of ATII (1.0 micrograms) + saralasin (SAR, an analog ATII) (5.0 micrograms), on behavioral responses of the defensive burying paradigm were studied. ATII-treated animals displayed significantly less defensive burying behavior (less time spent in defensive burying and less frequent burying than in vehicle-treated rats) in a dose-dependent manner. SAR at a dose of 5 micrograms did not affect burying behavior significantly; it also did not modify the inhibition effects of ATII on behavioral responses of the defensive burying test. These results provide evidence that ATII can exert anxiolytic actions on central transmitter systems mediating conditioned fear-related behaviors (i.e., defensive burying). The present study suggests that the defensive burying animal model is a rather sensitive test fulfilling the pharmacological criteria of dose-dependent sensitivity for studying the central effects of neuropeptides (e.g., ATII).

Agonistic Behavior↗
PubMed1992

[Successful surgical treatment of coronary aneurysm following PTCA].

A case of 50-year-old man who developed coronary aneurysm at the initial PTCA site following dilatation was reported. The patient was suffered severe effort angina pectoris and admitted to our hospital. Coronary angiography revealed 99% stenosis in the right coronary artery (RCA), and the underwent balloon dilatation of the RCA lesion with 3.0 mm balloon catheter at 3 atm of pressure. PTCA provided sufficient coronary dilatation, however a small dissection remained. He was discharged from the hospital without any symptom. Two months after PTCA he was suffered from recurrent angina, and electrocardiographic exercise stress test was positive for ST segment depression in inferior wall. The repeat coronary angiography showed severe stenosis of the original lesion and aneurysm formation at the area of dissection which occurred during initial angioplasty. Coronary artery bypass surgery with a saphenous vein graft performed successfully.

Angioplasty, Balloon, Coronary↗
PubMed1991

Characterization of rehydrated gelatin gels.

Five percent glutaraldehyde cross-linked gels have shown excellent blood compatibility as coatings for cardiac prostheses. A method was developed for producing thin dehydrated coatings using a proprietary dehydration procedure and ethylene oxide (EO) sterilization. The swollen surfaces of rehydrates versus wet (original) gels were compared. Within 30 min of saline rehydration, dry 30-50-microns films on textured surfaces became smooth, uniform, and comparable to original gelatin gels. Mechanical test results after rehydration showed values for strain remain unchanged (39.3 + 10.0 to 40.0 + 7.8%), but stress increased (2.79 + 1.21 to 4.22 + 1.60 dyne/cm2; p less than 0.01). The contact angle data reported gamma C values of 26.1 and 30.4 dyne/cm for original and rehydrated gels. Using a coulometric titrimeter, the measured water content of original gels was reduced from 85 to 3.4% after drying. Dried and saline rehydrated gels had a 73.2% moisture content. Gels shrank 8.8% of their original length after rehydration; however, the thickness of all pump coatings remained stable. Two-hour incubations with bovine platelet rich plasma showed no differences in platelet reactivity or morphology when compared to original gels. Light microscopy and scanning electron microscopy (SEM) showed no evidence of gel cracking or surface defects after pump endurance testing for 3 and 5 weeks. The process of dehydration eliminates the wet storage and sterility problems of such hydrogels and provides a stable film coating for a variety of blood-contacting substrates.

Biocompatible Materials↗
PubMed1991

Effects of single-dose infusion of pyridoxalated-hemoglobin-polyoxyethylene conjugate solution on canine renal function.

Pyridoxalated-hemoglobin-polyoxyethylene conjugate (PHP) is an acellular oxygen-carrying red blood cell substitute made from outdated human red blood cells. This study assessed the effect of PHP on renal function when PHP was infused with a clinically relevant dosage. A single dose of PHP that contains 8% wt/vol each of hemoglobin and maltose or an 8% maltose control solution was infused into the intact circulation of eight dogs (five dogs for PHP and three for the control; 20 ml/kg each, at the rate of 2.5 ml/h/kg for 8 h) in the awake state. Serial measurements of glomerular filtration rate (GFR) and renal plasma flow (RPF) were carried out before and after infusion for up to 2 weeks, along with determinations of urine volume flow rate, fractional excretion of sodium (FES), and free water clearance (CH2O). The results showed an elevation of plasma colloid osmotic pressure by an average of 4.4 mm Hg immediately postinfusion with PHP solution. An average 23% decrease in GFR, without notable changes in RPF immediately postinfusion, was observed in the PHP group; the value returned to the preinfusion level by 1 week postinfusion. Increases in parameters such as urine output, FES, and CH2O, which were more pronounced in the PHP group, were observed for 24 h after the infusion in both groups. Light microscopic examination of kidney specimens taken at 2 weeks postinfusion revealed a slight degree of vacuole formation in approximately 80% of the proximal tubules in the PHP group. The tubules were devoid of typical pathologic features of acute renal failure, and the vacuoles did not cause any observable changes in the assessed tubular functions.

Animals↗
PubMed1990

Vascular stenting in normal and atherosclerotic rabbits. Studies of the intravascular endoprosthesis of titanium-nickel-alloy.

Percutaneous transluminal balloon angioplasty would be more effective if the rate of recurrent stenosis were reduced. To evaluate the prevention of restenosis after percutaneous transluminal angioplasty, intravascular endoprosthetic stents of titanium-nickel-alloy were implanted transluminally in seven normal and 21 atherosclerotic rabbits. In normal rabbits, a 3.5-mm diameter stent was implanted in the aorta and a 2.5-mm diameter stent in the right iliac artery, which were followed with serial angiograms from 6 weeks (n = 7) to 8 months (n = 4). There was a mean stenosis of 13.1% in the 2.5-mm and 13.6% in the 3.5-mm stent. There was no significant narrowing compared with the adjacent control segments of artery; histopathology showed a thin, fibrous neointima with smooth muscle cells. Each atherosclerotic rabbit was balloon dilated at two separate stenotic sites; each site was 2.0 cm in length. The aortic site (with 28.8 +/- 13.8% mean stenosis [+/- SD]) was dilated with a 3.5-mm balloon, and the iliac site (with 36.5 +/- 14.2% stenosis) was dilated with a 2.5-mm balloon. In each site, an intravascular stent of corresponding diameter and 7-mm length was implanted in one half of the dilated segment, assigned randomly, and the other half served as the angioplasty control. Angiographically observed restenosis rates and the corresponding histopathology were similar in the atherosclerotic segments that had angioplasty alone versus the atherosclerotic segments that had angioplasty plus stenting. The mean neointimal thickness in the aortas and iliac arteries, respectively, measured 247 +/- 181 microns (+/- SD) and 218 +/- 77 microns after 6 weeks (n = 8) versus 321 +/- 168 and 308 +/- 189 microns after 20 weeks (n = 5, p = NS). At 20 weeks follow-up, there was 29.1 +/- 29.8% (median, 16.4%) stenosis in the aortic stent versus 38.9 +/- 24.1% (median, 34.0%) stenosis in the percutaneous transluminal angioplasty control segment of aorta (n = 5, p = NS) and 81.4 +/- 25.5% stenosis in the iliac artery stent versus 89.3 +/- 15.3% stenosis in the PTA control segment of the right iliac artery (n = 5, p = NS). Comparing stenotic arterial segments treated with angioplasty alone with angioplasty plus intravascular stenting in the atherosclerotic rabbits showed that there was no significant difference in either the histopathologic changes or the restenosis rates.

Alloys↗
PubMed1990

Benign exertional headaches induced by swimming.

A 57 year-old woman with benign exertional headaches induced by swimming is described. The headaches were bilateral, throbbing and occurred while swimming. She had a history of occasional similar headaches while straining during bowel movements. The neurological examination and computed tomographic (CT) scanning were normal. The electroencephalogram (EEG) had diffuse alpha activity, and no symptoms or significant changes of the EEG were triggered by the Valsalva maneuver, which causes a transient increase in cranial blood pressure and alters the normal vascular balance. She has stopped swimming and since then has never had a headache. No medications were needed. This case demonstrates that not all headaches are triggered by intracranial lesions. Benign exertional headaches should also be considered in the differential diagnosis of this type of headache in the elderly.

Female↗
PubMed1986

[Pressure gradient across the mitral valve in mitral stenosis estimated by high pulse repetition frequency Doppler method].

High pulse repetition frequency (HPRF) Doppler and continuous wave (CW) Doppler methods were used to estimate the pressure gradient across the mitral valve. Twenty-two cases of mitral stenosis and five cases of ischemic heart disease were studied. Both the HPRF and CW Doppler studies were conducted during catheterization in all cases. In the Doppler study, pressure gradient was calculated using the simplified Bernoulli's formula. The HPRF device used was a type SSD-730 produced by Aloka Co. It had a reference frequency of 2 MHz. Its minimum pulse repetition frequency was 4.2 KHz; its maximum, 19.2 KHz. Among the 27 cases, the maximum flow velocity measured by the HPRF method at the level of the mitral valve orifice was compared with that by the CW method. As the velocity increased, the discrepancy of measured values between the two methods increased, but it was within 0.1 m/sec. Therefore, there was a good correlation between the HPRF and CW methods (r = 0.98). The pressure gradient between time delay-corrected pulmonary artery wedge pressure and left ventricular pressure was compared with that obtained by the HPRF method. Contrary to our expectations, the correlation coefficient between the two was not so high, and the pressure gradients calculated by the HPRF method tended to be underestimated. For eight patients in whom the left atrial pressure could be recorded, the pressure gradient between the left atrium and left ventricle was compared with that obtained by the HPRF method. There was underestimation, and a good correlation coefficient was obtained. When using pulmonary artery wedge pressure as a substitute for left atrial pressure, one must realize that the time delay varies in every case and that the pressure pulse itself is not the same. When the pressure gradient between the left atrium and left ventricle is used, a good correlation coefficient can be obtained. Therefore, the flow velocity obtained by the HPRF method will reflect the true pressure gradient across the mitral valve. The HPRF method proved to have a potential equal to that of the CW method for estimating mitral valve flow velocity in mitral stenosis, and it may be used as a helpful diagnostic tool.

Adult↗
PubMed1984

Dynamic patch artificial myocardium; effects on the residual myocardial function.

Dynamic patch artificial myocardium (D-PATCH) has been developed to replace the damaged left ventricular (LV) wall in severe cardiogenic shock patients with a massive myocardial infarction. This study was undertaken to demonstrate the effects of (1) single D-PATCH support on the global cardiac function (group 1, 12 dogs, whole heart model), (2) single D-PATCH support on the LV function and myocardial metabolism (group 2, 6 dogs, right heart bypass model), and (3) the concomitant support of D-PATCH and aortic counterpulsation (CP) on the regional myocardial function of the residual LV wall (group 3, 6 dogs, right heart bypass model with ultrasonic piezoelectric crystals). In group 1, mean aortic pressure and cardiac output were increased 20-36% (p less than 0.01) and 17-50% (p less than 0.01) respectively, and mean left atrial pressure was decreased 16% (p less than 0.01) by D-PATCH assist. In group 2, under constant preload volume, afterload pressure and heart rate, tension time index (TTI) was decreased 21-26% (p less than 0.01) and myocardial oxygen consumption was also decreased 24-29% (p less than 0.001) by D-PATCH assist. In group 3, although peak LVP was increased by single D-PATCH assist, when heart was assisted concomitantly by D-PATCH and CP peak LVP was significantly decreased (18%, p less than 0.01). Percent LV segmental shortening was not increased by CP assist, but increased 143% (p less than 0.02) by D-PATCH assist. In conclusion, D-PATCH can improve the global LV function and myocardial metabolism of the ischemic failing heart, also improve the regional myocardial function of the residual LV wall. Thus, D-PATCH is effective for the salvage of ischemic myocardium while maintaining the global cardiac function.

Animals↗
PubMed1984

[Real-time two-dimensional Doppler echocardiography in congenital heart disease: its clinical significance].

This study demonstrated the diagnostic usefulness of the newly-developed real-time two-dimensional Doppler echocardiography (2-D Doppler) in congenital heart disease. Among fifty-four patients with congenital heart disease, 18 had ASD; 16, VSD; 6, T/F; 3, PDA; 3, d-TGA; 3, ECD; and 1 each, DORV, PA, PS, Ebstein's anomaly, and ruptured aneurysm of the sinus of Valsalva. Each diagnosis was confirmed by cardiac catheterization and/or surgery. Forty normal cases were subjected as the control. The study cases included 26 adults and 28 children under 15 years old, 13 infants and seven newborns. In 52 cases (96.3%) 2-D Doppler provided diagnostic abnormal intracardiac blood flow images which were compatible with the data of cardiac catheterization and cardiac angiography and/or patients' cardiac anatomy observed during surgery. The blood flow data obtained by 2-D Doppler facilitated determining the appropriate timing of palliative surgery such as the Blalock-Taussig shunt procedure. 2-D Doppler was effective in evaluating medical (pharmaco-echocardiography) and surgical therapy including radical and palliative procedures for congenital heart disease. Thus, 2-D Doppler proved a non-invasive and useful diagnostic method for congenital heart heart disease. Our data suggest that with this technique cardiac surgery can be performed without cardiac catheterization or cardiac angiography in some cases of congenital heart disease.

Adult↗