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Biomedical subjects

S Daikoku

Publications and source records attributed to S Daikoku.

At least 55 records · Page 3Linked to original sources

Successful retrieval of unexpanded Palmaz-Schatz stent from left main coronary artery.

A 64-year-old patient with silent myocardial ischemia after anterior myocardial infarction was treated with directional coronary atherectomy, balloon angioplasty, and placement of Palmaz-Schatz stent. An unexpanded Palmaz-Schatz stent was retained in the left main coronary artery and was treated successfully with a nitinol goose-neck snare. After this procedure, another Palmaz-Schatz stent was successfully implanted without any complications.

Angioplasty, Balloon, Coronary↗

Antiischemic effect of intracoronary diltiazem on myocardial ischemia during PTCA.

To evaluate the effect of intracoronary diltiazem on myocardial ischemia during percutaneous transluminal coronary angioplasty (PTCA), 38 patients were randomly assigned to receive inactive placebo (n = 19; group C) or a low dose (1 mg, n = 10; group D1), or a high dose (2 or 3 mg, n = 9; group D2) of diltiazem in a double-blind manner. The agent was administered directly into the coronary artery via a balloon catheter following a control balloon inflation. Chest pain score (maximum, 10) and the magnitude of ischemic ST elevation on standard and intracoronary electrocardiograms (ECGs) during a balloon inflation were assessed in the control and posttreatment periods. After the administration of diltiazem, the chest pain score was significantly decreased in group D1 (control: 5.1 +/- 3.6, posttreatment: 3.8 +/- 3.1, P < 0.01) and group D2 (3.4 +/- 2.5 vs 2.5 +/- 2.0, P < 0.01), but not in group C (4.1 +/- 3.1 vs 3.7 +/- 3.3, difference not significant). The magnitude of ST elevation relative to the control on standard and intracoronary ECGs was significantly smaller in groups D1 and D2 than in group C (standard ECG; D1: 51.8 +/- 10.6% of control, D2: 41.6 +/- 28.7% vs C: 93.3 +/- 15.6% and intracoronary ECG; D1: 47.1 +/- 11.7% of control, D2: 27.5 +/- 26.9% vs C: 94.6 +/- 29.3%, all P < 0.01). Although systolic blood pressure decreased slightly in groups D1 and D2, there was no significant correlation between the change in ST elevation and the change in the rate-pressure product. Pretreatment with a small dose of intracoronary diltiazem attenuated myocardial ischemia during PTCA and this pretreatment may enable us to perform balloon inflation for a longer period.

Angina Pectoris↗

Enhancement of coronary reactive hyperemia in patients with ischemic myocardial tolerance during angioplasty.

The purpose of this study was to elucidate the effect of repeated brief coronary occlusions on reactive hyperemia during percutaneous transluminal coronary angioplasty (PTCA) in patients with or without ischemic tolerance. Seventeen patients undergoing PTCA for chronic stable angina were studied. Patients with well developed collateral vessels were excluded. After successful predilatation, coronary flow velocity was recorded with the use of a Doppler flow guide wire, and reactive hyperemia was assessed immediately after each of two 2-min coronary occlusions followed by 2 mins of reperfusion. The intracoronary electrocardiogram (icECG) was recorded via the flow guide wire placed in the center of the ischemic zone. Patients were divided into two groups: those who showed a reduction of ST elevation in the icECG recorded at the time of the second coronary occlusion (group I), and those who showed no difference in ST elevation between the two occlusions (group II). There were no significant differences in blood pressure, heart rate, or baseline coronary flow velocity between the two groups before the first occlusion, but the ST elevation at the time of the first coronary occlusion was greater in group I than in group II (8.9 +/- 6.2 versus 1.1 +/- 2.0 mm, P < 0.01). Reactive hyperemia was significantly greater after the second coronary occlusion than after the first in group I (22.1 +/- 15.8 versus 30.4 +/- 21.0 cm/s, P < 0.05), but it did not change in group II (25.6 +/- 13.0 versus 23.5 +/- 11.2 cm/s NS). Reactive hyperemia was enhanced in patients with ischemic tolerance who showed a reduction in St elevation in the icECG. These results suggest that observed reactive hyperemia does not necessarily reflect the severity of ischemia.

Aged↗

[Acute myocardial infarction in young Japanese women].

Women appear to be protected, until the menopause, from the development of coronary artery disease. The incidence of acute myocardial infarction in young women is very low, so there is little information on the etiology, clinical features, and prognosis for such patients. We studied 24 young female patients with acute myocardial infarction (< 50 years) among 2,457 consecutive patients with acute myocardial infarction admitted to the coronary care unit of the National Cardiovascular Center from December 1977 through August 1994. Their clinical features and in-hospital mortality were compared with 100 consecutive young male patients (< 50 years) with acute myocardial infarction. The fraction of patients of age younger than 50 years among all age groups was lower in female than in male acute myocardial infarction patients (5% vs 13%, p < 0.01). The increase of the coronary risk factors, hypercholesterolemia (25% vs 55%, p < 0.05) and cigarette smoking (17% vs 96%, p < 0.05) were less common in women. In female patients, the serum total cholesterol level was lower (195 +/- 50 vs 216 +/- 48 mg/dl, p = 0.06), and the serum high-density lipoprotein cholesterol level was higher (50 +/- 12 vs 39 +/- 12 mg/dl, p < 0.05) than in male patients. Other risk factors did not differ significantly between the two groups. Angiography 1 month after myocardial infarction showed fewer diseased coronary arteries (> 75% stenosis) in female than male patients (0.8 +/- 0.9 vs 1.8 +/- 1.0, p < 0.01), and normal coronary arteries were seen in 35% of female patients (male 6%, p < 0.05). Ten female patients (42%) had obviously non-atherosclerotic causes of acute myocardial infarction: Takayasu aortitis in three patients, coronary embolism in two, acute dissection of the aorta in two, and idiopathic coronary artery dissection, Kawasaki disease, and systemic lupus erythematosus in one each. In contrast, among male patients, only one had coronary embolism (1%). In-hospital mortality was higher in women (17%) than in men (2%, p < 0.05). Young female patients (< 50 years) with acute myocardial infarction have a low incidence of hyperlipidemia and normal coronary arteries or involvement of the left main trunk are more common compared with male patients (< 50 years). Although 42% of female patients had obvious non-atherosclerotic etiology of acute myocardial infarction, the causes varied widely.

Adult↗

Gadolinium-enhanced magnetic resonance imaging in acute myocardial infarction.

To investigate the clinical application of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA)-enhanced magnetic resonance imaging (MRI) in the management of acute myocardial infarction (AMI), we examined 44 patients with AMI within 1 month after onset. Enhanced images were classified into 4 types: nontransmural (type 1), transmural and homogeneous (type 2), transmural and marginal (type 3), and no enhancement (type 4). Each enhancement pattern was correlated with angiographic and thallium-201 imaging results. The redistribution images of thallium were graded on a 4-point scale from 0 (normal) to 3 (markedly reduced or absent activity). The percentage of the perimeter affected by asynergy was obtained from the left ventriculogram. Peak creatine kinase and the percentage of asynergic perimeter were significantly higher in type 3 than in other type patients. End-diastolic volume index was significantly higher in type 3 than in type 2 patients. Left ventricular ejection fraction was lowest, and end-systolic volume index, thallium-201 score, and incidence of wall thinning on MRI were highest in type 3 patients. Therefore, the transmural and marginal enhancement pattern (type 3) was compatible with extensive myocardial infarction with infarct expansion and less viable myocardium. In the other types, the infarction was small to moderate in size and left ventricular function was well preserved. Thus, Gd-DTPA-enhanced MRI may be useful in the evaluation of left ventricular function and myocardial viability of the infarct region after AMI.

Aged↗

Angioscopic prediction of successful dilatation and of restenosis in percutaneous transluminal coronary angioplasty. Significance of yellow plaque.

BACKGROUND: Coronary angiography has been used to assess the anatomy of coronary artery and intraluminal pathological changes. However, it has several limitations in its diagnostic quality and sensitivity in the detection of intraluminal details. Angioscopy has enabled coronary artery lumens to be visualized directly and fine intraluminal morphological changes to be detected. The information obtained by angioscopy is expected to provide new insights into the mechanisms and pathophysiology of transluminal coronary angioplasty. METHODS AND RESULTS: Forty-seven patients (39 men and 8 women) with stable angina were enrolled in the present study. Angioscopy was performed before and after angioplasty with a 0.68-mm angioscope with a double-guiding catheter system. The patients who were successfully evaluated by angioscopy were divided into two groups according to the color of the lesion: group 1, mainly yellow; and group 2, white. Angiographic, angioscopic, and clinical parameters in the two groups were compared. Detailed angioscopic findings were obtained in 36 of the 47 patients (77%) before percutaneous transluminal coronary angioplasty (PTCA) and in 24 of the 47 (51%) after PTCA. Yellow plaque were found in 13 of 36 (36%). Age, sex, presence of coronary risk factors, serum cholesterol level, and duration of angina showed no correlation with plaque color. The incidence rates of dissection and thrombi after angioplasty also were not different. Successful dilatation was achieved in 13 of 13 patients (100%) in group 1 and in 21 of 23 (91%) in group 2. The restenosis rate of group 1 was significantly lower than that in group 2 (16.7% versus 57.9%, P < .05). Cox proportional hazards model revealed that plaque color was the independent variable associated with restenosis after PTCA (P = .03). CONCLUSIONS: The restenosis rate after successful balloon angioplasty differs, with the color of the target lesion being significantly higher in patients with solely white plaque. Therefore, angioscopic findings are highly predictive of restenosis.

Angina Pectoris↗

Comparison of vessel wall morphologic appearance at sites of focal and diffuse coronary vasospasm by intravascular ultrasound.

Coronary vasospasm is manifested by either focal or diffuse pattern in clinical settings. To examine the differences in vessel wall morphologic appearance between the sites of focal and diffuse vasospasm, we studied 29 patients with chest pain at rest, during exertion, or both by intravascular ultrasound. By angiography, focal vasospasm with diameter reduction of 90% +/- 3% (mean +/- SD) was provoked by intracoronary ergonovine (0.01 to 0.04 mg) in 15 patients. Diffuse vasospasm with diameter reduction of 79% +/- 5% (NS) was provoked in seven patients, and the remaining seven patients served as the control group. By ultrasonography, a significantly thickened intimal leading edge with sonolucent zone was observed in 55 sites from 22 coronary arteries with either focal or diffuse vasospasms (0.61 +/- 0.32 mm), although these sites were normal or minimally narrowed by angiography. Seven segments from the control group exhibited a thin intimal leading edge with sonolucent zone (0.23 +/- 0.08 mm, p < 0.01). When the thickness of the intimal leading edge with sonolucent zone was compared between the abnormal sites with focal and diffuse vasospasm, this was significantly greater at focal spasm, 1.01 +/- 0.35 mm (n = 15), than that at diffuse spasm, 0.46 +/- 0.13 mm (n = 40, p < 0.01). At the sites with diffuse spasm, some of the lesions lay scattered along the coronary vessels, although the lesions were localized at the sites of focal vasospasm. These results indicate that atherosclerosis is present at sites with both focal and diffuse vasospasm even in the absence of angiographically significant coronary artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Serum cardiac troponin T in patients with acute myocardial infarction. Detection of coronary reperfusion and prediction of cardiac function.

Serum troponin T, a myocardial contractile protein, has been reported to be a sensitive marker for the diagnosis of acute myocardial infarction. However, there have been few reports on its ability to detect coronary reperfusion and to predict left ventricular function in the chronic stage. Twenty two patients (20 males and 2 females, 61 +/- 10 y.o.) with acute myocardial infarction were enrolled in this study. They were divided into 2 groups, one with successful reperfusion (group A: n = 13) and one without reperfusion (Group B: n = 9) and the serial changes of their serum troponin T levels were evaluated. Serum myosin light chain was measured in another group of patients with acute myocardial infarction without history of old myocardial infarction (group C: n = 8). The slope of the logarithm of serum troponin T on a time-value curve was calculated from the time of admission to the first peak within 24 hours of the onset of acute myocardial infarction. The correlation coefficient between the late peak of serum troponin T and the left ventricular ejection fraction in 11 patients with first Q wave acute myocardial infarction was compared with that between the serum myosin light chain peak and the left ventricular ejection fraction in group C. 1) The slope of the logarithm of serum troponin T on the time-value curve in group A was greater than that in group B (0.57 +/- 0.45 vs. 0.22 +/- 0.16) (p < 0.05). 2) There was a good correlation between the late peak level of serum troponin T (78 +/- 10 hours after the onset) and the left ventricular ejection fraction in 11 patients with first Q wave acute myocardial infarction (r = -0.84, p < 0.01), which was similar to that of the serum myosin light chain peak and the left ventricular ejection fraction (r = -0.72, p < 0.05). On the other hand, there was no correlation between the peak level of serum creatine phosphokinase and the left ventricular ejection fraction (r = -0.55, NS). The serum troponin T levels 24, 36, 48 and 60 hours after the onset also correlated well with the left ventricular ejection fraction (r = -0.65, -0.7, -0.65 and -0.89, respectively). We conclude that the serial measurement of serum troponin T in patients with acute myocardial infarction is useful in the evaluation of left ventricular function in the chronic stage and that it is a potential non-invasive predictor of coronary reperfusion.

Aged↗

In vitro analysis of the centripetal migration mechanisms of developing LHRH neurons.

This study was designed to gain insight into the underlying mechanisms of the centripetal migration of developing LHRH neurons. The medial wall of the nasal pit (NAP) of 12.5-day-old rat embryos (E12.5) was cultured singly or together with the E12.5 medial-basal wall of the forebrain vesicles (mFV) or with the E14.5 median eminence-arcuate complex (ME-Arc). Further, the NAP was cultured with the mFV and ME-Arc or with the mFV and nasal mesenchyme (NM), which lay between the mFV and the NAP, of E12.5 embryos (triple culture). The NAP gave rise first to fibers labeled with anti-neural cell adhesion molecules (NCAM) and then to LHRH neurons. In co-cultures, NAP- and brain-derived NCAM fibers connected the NAP and brain cultures, and frequently linked with each other to form knots at the periphery. LHRH neurons migrating along the NAP-derived fibers directly or indirectly entered brain cultures. In the latter case, the cells strayed along the way from the NAP-derived fibers to the brain-derived fibers at the knots and migrated retrogradely along the latter fibers to enter into the brain tissues; this occurred most frequently into the E14.5 ME-Arc. In triple cultures, abundant NCAM fibers emerging from the NAP were only found when the NM lay between the NAP and mFV; the fibers converged further to the mFV. These findings help elucidate the mechanisms underlying the centripetal LHRH cell migration from the NAP to the hypothalamus.

Animals↗

How the developing septo-preoptic medical basal hypothalamus stimulates the development of placode-derived LHRH neurons.

We examined the effects of the developing cerebral cortex (CC) and septo-preoptic medial basal hypothalamus (S-MBH) on the development of LHRH neurons in vitro. The serum-free basal culture medium (BCM) was supplemented with CC or S-MBH extracts prepared from 18.5-day-old embryos or from 2-day-old newborns, and the olfactory placode (NAP) of 12-day-old embryos was cultured. The migration of LHRH neurons was found on Day 3 in the cultures supplemented with the embryonic S-MBH extract (Group 3), where the cell development proceeded showing a numerical increase of the cells and the elongation of neurites. In cultures supplemented with the newborn S-MBH extract (Group 5), the cell development was less intensive in comparison with that of Group 3, while in cultures which had no brain extracts (Group 1), the neurons failed to survive a long term culture. The effects of the CC were less than of S-MBH extracts. Analysis of the protein composition of the extracts by electrophoretic and immunoblotting examinations demonstrated a protein spot of 70-kD in the embryonic S-MBH extract. Because the protein spot was identified to be alpha-fetoprotein (AFP), we further examined the effects of AFP. When the anti-AFP immunoglobulin was added to the Group 3 culture, the stimulative effects of the embryonal extract were inhibited, and the addition of AFP to Group 1 cultures did not show stimulative effects. We conclude that the developing S-MBH, the migrating target of LHRH neurons, contains some essential factors for the development of LHRH neurons, but further analysis is needed to determine the chemical natures of these factors.

Animals↗

[Prognostic significance of signal averaged electrocardiogram in survivors after myocardial infarction].

We evaluated the relationships between the prognosis and the presence of late potentials (LP) on signal averaged electrocardiogram (SAE) in 165 patients surviving an acute myocardial infarction (MI). SAE was performed four weeks after the onset of MI. Arrhythmic events was defined as nonsustained ventricular tachycardia (VT), sustained VT and ventricular fibrillation. LP was detected in 41 (25%) of 165 patients. Patients with LP had dilated left ventricle and lower ejection fraction. At a mean follow-up of 4.4 years, 6 of 124 patients (5%) without LP and 20 of 41 patients (49%) with LP had a late arrhythmic event. Arrhythmic death and sudden death were observed in 2 patients (2%) without LP and in 9 patients (22%) with LP.

Aged↗

[Clinical significance of late potential in patients with dilated cardiomyopathy].

Signal-averaged electrocardiography is used to demonstrate low amplitude, high frequency late potential (LP) that represents areas of slow conduction and substrate for reentrant ventricular arrhythmias. Usefulness of LP has been established in patients with chronic ischemic heart disease. However, clinical significance of LP in patients with dilated cardiomyopathy remains to be clarified. We studied the relationships between LP and clinical characteristics in 34 patients with dilated cardiomyopathy. In 20 patients we evaluated the inducibility of sustained ventricular tachycardia (S-VT) using programmed electrical stimulation (PES). LP was detected in 20 of 34 patients. No statistical differences were observed between patients with LP and patients without LP in the incidence of congestive heart failure, hemodynamic parameters and mortality. But, patients with LP had higher incidence of spontaneous S-VT. S-VT was induced in 10 of 15 patients with LP and in none of 5 patients without LP. LP was an excellent indicator of the spontaneous incidence and inducibility of S-VT in patients with dilated cardiomyopathy.

Body Surface Potential Mapping↗

Chromaffin cells express Alzheimer amyloid precursor protein in the same manner as brain cells.

Amyloid precursor protein (APP) 695 is remarkably expressed in the brain as compared with APP751 and APP770 which are dominant in other tissues. This study showed that human and bovine adrenal medullae dominantly expressed mRNA of APP695 as do brain nerve cells, while the adrenal cortexes expressed mRNAs of APP751 and APP770 as in other non-neural tissues. In immunohistochemistry, chromaffin cells of young rat adrenal medullae and primary cultured bovine chromaffin cells were significantly stained with a monoclonal antibody (mAb) against the common domain of the amino-terminal side of human APPs. At higher magnification, the immunostained cells revealed that APP was granularly distributed not only in the perikaryon but also in the cell processes. These results suggest that primary cultured chromaffin cells representing the state of adrenal medulla in vivo are a useful model for studying the pathophysiological functions of APPs and the mechanism of processing of APPs as a model of neuronal systems.

Adrenal Cortex↗

In vitro development of placode-derived LHRH neurons: possible involvement of alpha-fetoprotein.

Using the olfactory placode (NAP) of 12.5-day-old and vomeronasal organ (VNO) of 14.5-day-old (E12.5, E14.5) rat embryos, we examined in vitro the roles of brain tissues in the development of LHRH neurons. The culture was performed singly or in combination with various brain tissues of E12.5 and E14.5 embryos. Furthermore, a serum-free basal culture medium was supplemented with a water extract of cerebral cortex or septopreoptic-medial basal hypothalamus (S-MBH) of E18.5 embryos and 2-day-old (N2) newborns. In cocultures, many LHRH cells derived from the NAP or VNO migrated into the collocated tissues of the forebrain vesicles and medial basal hypothalamus, especially into the latter, along neural cell adhesion molecule (NCAM)-positive fibers projecting from the NAP and/or the brain tissues, especially in the case of the medial basal hypothalamus. The effects of the brain extracts were evaluated by differentiation, migration, neurite extension, and survival of LHRH neurons. E18.5 S-MBH extract was most effective. In the analysis of the protein composition of the extracts, alpha-fetoprotein (AFP) was determined only in the E18.5 S-MBH extract. When anti-AFP IgG was added to the cultures containing E18.5 S-MBH extract, the stimulative effects of the extract were reduced to the level of the N2 S-MBH extract. When we cultured the NAP by adding AFP in the basal culture medium, the development of LHRH cells was somewhat promoted. The actual roles of AFP thus remain to be further elucidated.

Animals↗

Immunohistochemical studies on sympathetic and non-sympathetic nerve fibers and neuronal cell bodies in the pineal gland of cotton rats, Sigmodon hispidus.

Immunohistochemistry revealed the presence of tyrosine hydroxylase (TH)-, neuropeptide Y (NPY)-, calcitonin gene-related peptide (CGRP)- and substance P (SP)-immunoreactive nerve fibers and SP-immunoreactive neuronal cell bodies in the pineal gland of the cotton rat (Sigmodon hispidus). Abundant TH- and NPY-immunoreactive fibers were distributed evenly throughout the gland; less numerous CGRP- and SP-immunoreactive fibers were distributed in the superficial pineal and the stalk, but were scarce in the deep pineal. All the immunoreactive fibers were usually found around blood vessels. Since TH- and NPY-immunoreactive fibers in various pineal regions disappeared completely with superior cervical ganglionectomy, these fibers are all considered postganglionic sympathetic fibers. Intrapineal CGRP- or SP-immunoreactive fibers decreased considerably in number following superior cervical ganglionectomy, suggesting that some sympathetic fibers contain CGRP or SP. Bilateral bundles of nerve fibers under the transverse sinuses, corresponding to the nervi conarii, contained TH-, NPY-, CGRP- and SP-immunoreactive fibers, which continued into those distributed in the pineal capsule. In the nervi conarii, fibers immunoreactive for TH and NPY disappeared after superior cervical ganglionectomy, but those immunoreactive for CGRP and SP persisted. Thus, non-sympathetic, CGRP- and SP-immunoreactive fibers, together with sympathetic fibers, are presumed to enter the gland by way of the nervi conarii. Neuronal cell bodies, containing SP-like immunoreactivity and being possibly parasympathetic in nature, occurred occasionally in the superficial pineal.

Animals↗

Mutual synaptic associations between neurons containing neuropeptide Y and neurons containing enkephalin in the arcuate nucleus of the rat hypothalamus.

We determined reciprocal synaptic associations between neurons containing neuropeptide Y (NPY) and neurons containing enkephalin-8 peptide (Enk-8) in the arcuate nucleus (ARC) of the rat hypothalamus by using a double-staining immunocytochemical method. Animals treated with an intraventricular administration of colchicine and animals treated with a hemicomplete cut of the medial basal hypothalamus were used. We principally labeled NPY with silver-gold particles and Enk-8 with diaminobenzidine (DAB) chromogen but in part labeled reversely the two antigens to obtain better visualization of Enk-8 cell bodies. Neurons immunoreactive for NPY were found in the mediobasal area, while those for Enk-8 were located somewhat laterally. Their fibers, however, were densely distributed throughout the ARC in a similar fashion. Electron microscopically, we found synaptic junctions between axonal terminals of Enk-8 neurons and perikarya of NPY neurons and between axonal terminals of NPY neurons and perikarya of Enk-8 neurons. In addition, we found synaptic junctions between immunoreactive Enk-8 cell bodies and processes and also between immunoreactive NPY cell bodies and processes. These interneuronal associations may contribute to the interaction of information coming in or going out from this nucleus.

Animals↗

Migration of LHRH neurons derived from the olfactory placode in rats.

Using the olfactory placode of 12.5- and 14.5-day-old (E12.5, E14.5) rat embryos, we examined the migration of LHRH neurons by in vivo intraventricular transplantation and in vitro organotypic culture systems. In the transplantation, the olfactory placode of E12.5 embryos was co-transplanted with the cerebral cortex and also with medial basal hypothalamus (MBH). LHRH neurons that had migrated into the co-transplanted brain tissues were fusiform, but those that had moved into the neuro-mesenchymal tissue were polyhedral. The migration occurred most conspicuously in the MBH. In our in vitro studies, we used E14.5 embryos; their vomeronasal organ was cultured with MBH, the olfactory cortex, and the septum of the telencephalon in two systems (piled-culture with an intervening transferrable membrane and co-culture). Among these brain tissues, the MBH was the most effective in inducing the development and migration of LHRH neurons. We further found synaptic junctions of immunonegative nerve fibers on immunoreactive LHRH neurons located in the septum of E16.5 and 17.5 embryos. These findings suggest that the MBH may lead the intraseptal migration of LHRH neurons by yielding certain substances after introducing the neurons into the medial aspect of forebrain vesicles. The early development of the neuronal connection may further promote the migration of LHRH neurons.

Animals↗