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Biomedical subjects

S Sano

Publications and source records attributed to S Sano.

At least 73 records · Page 4Linked to original sources
PubMed1998

Ventricular pressure-volume area (PVA) accounts for cardiac energy consumption of work production and absorption.

We briefly review that ventricular systolic pressure-volume area (PVA) can predict changes in myocardial O2 consumption (VO2) associated with cardiac work production (positive work) and absorption (negative work). PVA represents the total mechanical energy of cardiac contraction as it is an integral of mechanical energy generated during systole in the cardiac chamber. We have shown that PVA linearly correlates with VO2 under varied pre- and afterload conditions in the left ventricle of the excised cross-circulated canine heart preparation as well as other heart preparations of different species. PVA is the sum of external mechanical work (EW) and mechanical potential energy (PE) which is almost fully convertible to mechanical work without affecting VO2. To compare the energetic effects of cardiac work production and absorption, we varied the timing of the servo pump motion relative to left ventricular (LV) contraction. When the pump fills the LV during diastole and sucks (allows ejection) during systole, cardiac work is produced by the heart, and hence EW > 0. When the pump fills the LV during systole and sucks during diastole, work is absorbed by the heart, and hence EW < 0. The pressure-volume loop rotates counterclockwise when EW > 0. It rotates clockwise when EW < 0. As the result, PVA (= PE + EW) > PE when EW > 0; PVA < PE when EW < 0. We found that VO2 always linearly correlated with PVA regardless of the polarity of EW. Therefore, PVA is the unique determinant of VO2 in a cardiac chamber in a stable contractility.

Animals↗
PubMed1998

Intrapulmonary cystic lymphangioma: report of a case.

We describe herein the case of a 52-year-old man found to have a solitary pulmonary lymphangioma. Computed tomography (CT) scan demonstrated a nodule with homogeneous density and a well-defined border in the lower lobe of the right lung. T2-Weighted magnetic resonance imaging (MRI) revealed a nodule with homogeneously high signal intensity. The tumor was removed by partial resection, and pathologic examination confirmed a diagnosis of primary lymphangioma of the lung.

Humans↗
PubMed1998

[Successful repair of critical aortic stenosis with coarctation on the first day of life].

Successful open aortic valvotomy and end-to-end anastomosis were performed to the patient with critical aortic stenosis and CoA on the first day of life. A fetus was diagnosed as aortic stenosis and coarctation by fetal echocardiography at 29 weeks of gestation. The mother was transferred to our hospital at the onset of labor and delivered vaginally at 40 weeks of gestation. Soon after the birth, the newborn, birth weight 2630 gram, female, underwent echocardiography by pediatric cardiologists which demonstrated the aortic orifice of 5.1 mm in diameter and thickened cusps with poor mobility. Transaortic pressure gradient measured by Doppler echocardiography was 111 mmHg and the left ventricular wall motion was hyperdynamic without any signs of endocardial fibroelastosis. Prostaglandin E1 administration was started to maintain systemic circulation and the hemodynamic status has been stable before surgery. On her first day of life, the operation was performed using cardiopulmonary bypass with moderate hypothermia. Isolated cerebral and myocardial perfusion technique was applied during the repair of coarctation of the aorta. The open aortic valvotomy with resection of myoxomatous nodules on leaflet edges effectively released pressure gradient across the aortic valve without regurgitation. Post-operative course was uneventful and she discharged at 28th day after surgery. We conclude early diagnosis including fetal echocardiography and early repair would lead the better surgical outcome to the neonates with critical aortic stenosis.

Alprostadil↗
PubMed1998

[Surgical repair of coronary sinus type partial anomalous pulmonary venous drainage with intact atrial septum].

We experienced a rare form of PAPVD without atrial septal defect. The patient was a 33-year-old male and he was referred to our institute because of mild right pulmonary congestion detected by a routine chest X-P. Enlarged coronary sinus, right atrium and right ventricle were documented by UCG. The Qp/Qs was 1.9 and pulmonary artery pressure was 38/7 mmHg (mean: 17 mmHg) by cardiac catheterization. Selective pulmonary angiogram showed that all right pulmonary veins drained into the coronary sinus without evidence of an atrial septal defect. Enhanced chest CT clearly demonstrated the connection between the right pulmonary vein and the coronary sinus. Intracardiac repair without atrial baffle was carried out under hypothermic cardiopulmonary bypass. Under cardiac arrest with cardioplegia, the common wall between the right pulmonary vein and the left atrium was incised and the connection between the right pulmonary vein and the left atrium was established. The flap made by this incision was brought posterior to close the right pulmonary vein opening to the coronary sinus. The postoperative course was uneventful and the minimum diameter of the right pulmonary vein was found to be 15.5 mm by a postoperative pulmonary artery angiogram. This operative method without an atrial baffle could be an alternative procedure for coronary sinus type PAPVD.

Adult↗
PubMed1998

[Norwood procedure to hypoplastic left heart syndrome].

Since March 1992, 25 neonates and small infants with HLHS have undergone a modified Norwood procedure. The mean age and weight at operation were 17 days (2 days-2 months) and 2.7 kg (1.6-3.3 kg). Isolated cerebral and/or myocardial perfusion (ICMP) with direct anastomosis of aorta and pulmonary artery was utilized since January 1995 to 16 patients. Under median sternotomy, PTFE graft (usually 3.0-3.5 mm) was anastomosed to the brachiocephalic artery and the arterial cannula was inserted to this PTFE graft. The left carotid and the left subclavian arteries were snared and a clamp was placed on the aortic arch just distal to the brachiocephalic artery. This allowed blood to enter the brain and the coronary arteries, keeping the brain perfused and the heart-beating. After reconstruction of distal aortic arch, a single dose of crystalloid cardioplesia was infused and the rest of the arch was reconstructed. There were 14 early deaths (56%) and 4 late deaths (16%). Bidirectional Glenn procedure was performed to 5 patients with 1 death. Three patients underwent modified Fontan procedure without mortality. Mean aortic cross clamp time was 24 min. and mean ICMP time was 32 min. There was no neurologic complications. In conclusion, isolated cerebral and/or myocardial perfusion may offer an advantage of protecting the brain and myocardium during arch in Norwood procedure.

Aorta↗
PubMed1998

Beneficial effects of prostaglandin E1 on ischemic colitis following surgery on the abdominal aorta.

To determine the effects of prostaglandin E1 (PGE1) on the intestinal circulation, an experimental dog model of ischemic colitis following abdominal aortic reconstruction was made by ligating the inferior mesenteric artery (IMA) and the internal iliac artery, with the creation of a 50% stenosis in the superior mesenteric artery (SMA). The parameters of enteric ischemia included the blood flow of the SMA, the tissue blood flow in the small intestine and left colon, the mean stump pressure of the IMA (IMAP), and the IMAP/mean systemic blood pressure ratio. With the continuous infusion of 10 ng/kg per minute of PGE1 into the descending thoracic aorta, these values increased significantly on the seventh postoperative day compared with those on the day of operation. These results thus suggest that the continuous intraarterial infusion of PGE1 may reduce ischemic changes in the colon following abdominal aortic reconstruction.

Alprostadil↗
PubMed1998

QT dispersion in dipper- and nondipper-type hypertension.

The aim of this study was to identify the relationship of QT dispersion on 12-lead electrocardiograms and left ventricular mass index on echocardiograms associated with the circadian rhythm of blood pressure (BP). Heart rate and BP were monitored every 30 min for 48 h in 62 patients with essential hypertension using an ambulatory BP monitoring device. The patients were divided into four groups according to gender and circadian BP pattern (nocturnal BP dipper or nondipper). The patients were classified as dippers if their daytime BP decreased by at least 10% during the night and all the other subjects were classified as nondippers. Age, body mass index, and 48-h mean BP were similar among the four groups. During the night-rest period, the systolic and diastolic BP were significantly decreased in dipper-type hypertensives. The maximum QTc interval and QTc dispersion were longer in nondippers than in dippers. Left ventricular mass index (LVMI) had a tendency to increase in nondippers. The nocturnal reduction of BP significantly correlated with QTc dispersion and LVMI. The QTc dispersion significantly correlated with LVMI and interventricular septum thickness.

Adult↗
PubMed1998

Candida is not involved in the development of of periungual psoriatic lesion.

Infection can be a trigger or an aggravating factor in psoriasis, and in particular, bacterial focal infection is well documented to exacerbate psoriasis presumably through its superantigen. Since fungi could produce superantigen as well, and periungual involvement is often seen in psoriatic patients, we examined if local Candida infection plays some pathogenetic role or not in periungual lesions. In 15 psoriatic patients with periungual involvement, Candida infection was examined by microscopic study, culture, and antifungal treatment. We found no evidence suggestive of the relationship between Candida and psoriatic changes in periungual area.

Adult↗
PubMed1998

Immunological study on CD3 defective cutaneous T cell lymphoma cells from a patient with Sézary syndrome.

Here we investigated the nature of cutaneous T cell lymphoma (CTCL) cells lacking surface CD3. A large number of CD3- CD4 T cells were found in the peripheral blood and lesional skin of a patient with Sézary syndrome, which is a variant of CTCL. Southern blot analysis revealed that a clonal rearrangement of T cell receptor (TCR) genes was detected in the separated CD3- CD4 cells, whereas CD3+ CD4 cells showed no clonal rearrangement, indicating that the CD3- CD4 cells represented CTCL cells. However, the CTCL cells expressed TCR with a particular Vbeta apart from CD3. The CTCL cells showed significant responses to staphylococcal enterotoxins (SEs) in vitro, although they hardly responded to phytohaemagglutinin, Mycobacterium tuberculosis antigen, and alloantigen. They required antigen-presenting cells (APC) to respond to SEB. Blocking analyses with MoAbs revealed that they recognized SEB through TCR depending on HLA-DR and intercellular adhesion molecule-1 (ICAM-1). Taken collectively, these results indicate that the CTCL cells lacking surface CD3 could proliferate in response to bacterial superantigens, whereas the responses to conventional antigens were generally suppressed. These results also implied that CTCL could be exacerbated by bacterial infection.

Antigen-Presenting Cells↗
PubMed1998

Prevalence of ventricular preexcitation in Japanese schoolchildren.

BACKGROUND: Wolff-Parkinson-White syndrome is thought to be a congenital disease, however, its exact prevalence is not known. This may be because of the intermittent activity of accessory pathways in some cases and fluctuations in autonomic tone. AIMS: To investigate the prevalence of ventricular preexcitation by electrocardiography and reported symptoms in each school age child in Yamanashi prefecture. METHODS: From 1994 to 1996, answers to a questionnaire, results of physical examination, and electrocardiography were obtained from all schoolchildren in Yamanashi prefecture (n = 92,161; total population 880,000) on admission to elementary school (age 6 to 7 years, n = 28,395), junior high school (age 12 to 13 years, n = 31,206), and high school (age 14 to 15 years, n = 32,837). RESULTS: Elementary and junior high school students had a significantly lower prevalence of preexcitation than high school students (0.073% and 0.070% v 0.174%, p < 0.001). The prevalence of left free wall pathway was highest in high school students (n = 27) compared with elementary (n = 6) and junior high school students (n = 5) (p < 0.005). The only symptom noted in the answers to the questionnaire was palpitations. The symptomatic cases were more frequent in high school (n = 13) than in elementary (n = 1) and junior high school (n = 2) children, but not significantly. No student with preexcitation had associated heart disease or family history of Wolff-Parkinson-White syndrome or sudden death. CONCLUSIONS: The prevalence of preexcitation in younger schoolchildren was less frequent than previously reported. The prevalence of preexcitation and left free wall pathways increased with age. The symptoms were few and there was no significant morbidity.

Adolescent↗
PubMed1998

Ventricular contractility in atrial fibrillation is predictable by mechanical restitution and potentiation.

We recently found that contractility (Emax) of an individual irregularly arrhythmic beat in electrically induced atrial fibrillation (AF) is reasonably predictable from the ratio of the preceding beat interval (RR1) to the beat interval immediately preceding RR1 (RR2) in the canine left ventricle. Moreover, the monotonically increasing relation between Emax and the RR1-to-RR2 ratio (RR1/RR2) passed through or by the mean arrhythmic beat Emax as well as the regular beat Emax at RR1/RR2 = 1. We hypothesized that this Emax-RR1/RR2 relation during irregular arrhythmia could be attributed to the basic characteristics of the mechanical restitution and potentiation. To test this, we adopted a known comprehensive equation describing the force restitution and potentiation as a function of two preceding beat intervals and simulated contractilities of irregular arrhythmic beats with randomized beat intervals on a computer. The simulated Emax-RR1/RR2 relation reasonably resembled the one that we recently observed experimentally, supporting our hypothesis. We therefore conclude that the primary mechanism underlying the varying contractilities of irregular beats in AF is mechanical restitution and potentiation.

Animals↗
PubMed1998

Dipyridamole thallium-201 single-photon emission computed tomography for prediction of perioperative cardiac events in patients with arteriosclerosis obliterans undergoing vascular surgery.

The aim of the study was to determine whether or not dipyridamole thallium-201 single-photon emission computed tomography (201Tl-SPECT) has significant additive value for predicting perioperative cardiac events in patients with arteriosclerosis obliterans (ASO) undergoing vascular surgery. Routine preoperative 201Tl-SPECT was performed in 106 consecutive patients with ASO (age 68+/-8.9 years; 91 men and 15 women). The frequency of reversible defects in a clinical high-risk group (n=44) was significantly higher than in a low-risk group (n=62; 55% vs 24%, p<0.01). Perioperative cardiac events occurred in 9 patients, including 4 cardiac deaths, 1 non-fatal myocardial infarction, and 4 cases of unstable angina. Although clinical risk stratification was useful in predicting cardiac events (19% in the high-risk group vs 2% in the low-risk group, p<0.01), the positive predictive value was low. When considering a combination of 2 or more than 2 risk factors and a large reversible defect as a predictor, the positive predictive value and specificity increased from 19% to 47% and from 64% to 91%, respectively, whereas the sensitivity remained unchanged (89%). These results suggest that the addition of 201Tl-SPECT data to clinical risk-stratified patients with ASO allows better prediction of perioperative cardiac events.

Adult↗
PubMed1998

Exercise-induced monomorphic ventricular tachycardia from the left ventricle outflow tract.

A case of exercise-induced idiopathic ventricular tachycardia (VT) arose from the left ventricular outflow tract. The QRS morphology of the VT was Rs pattern in V1 and R pattern in the lateral leads with inferior axis. The pacing at the superior interventricular septum near the mitral anulus produced the best pace mapping. Radiofrequency application to this site suppressed the VT.

Exercise↗
PubMed1998

Neonatal intrathymic splenocyte injection yields prolonged cardiac xenograft survival.

Intrathymic (i.t.) injection of allogenic cells without administration of anti-lymphocyte serum (ALS) in neonatal recipients has induced donor-specific tolerance to subsequent cardiac allografts in rats. This study examines whether similar tactics can be successfully applied to a hamster-to-rat cardiac xenotransplantation model. Lewis neonates on their first day of life underwent i.t., subcutaneous (s.c.), intraperitoneal (i.p.), or intravenous (i.v.) injections of 5 x 10(7) Golden Syrian hamster splenocytes. After six weeks, the rats underwent heterotopic cardiac transplantation of hamster hearts. Cyclophosphamide (CyP) was administered on the day before surgery and postoperatively to suppress antibody-mediated graft rejection. Rats given splenocytes with 80 mg/kg of CyP had the following graft survival times: 8 to 12 days for i.t. injection (mean, 9.4 days); 5 to 7 days for s.c. injection (mean, 6.6 days); 4 to 11 days for i.p. injection (mean, 7.4 days); and 4 to 13 days for i.v. injection (mean, 7.9 days). Only the extension of graft survival produced by i.t. injection was statistically significant in comparison with the rats given only CyP treatment (mean, 7.5 days; P < 0.05). Thus, it appears that i.t. injection of xenogenic splenocytes in neonatal recipients with administration of CyP, but without ALS, can prolong xenograft survival. This biological intervention may be most useful in pediatric xenotransplantation when combined with other immunomodulation techniques.

Animals↗
PubMed1998

Effects of endoluminal stent-grafts on acute aortic dissection in dogs.

Acute aortic dissection is a life-threatening condition, and may be treated with aggressive hypotensive drug therapy, but emergency surgery is often necessary. We evaluated the effectiveness of stent-grafts for the treatment of acute aortic dissection. Aortic dissection was surgically created in the descending thoracic aorta in 20 adult mongrel dogs. A stent-graft was inserted in the entry position. The tested animals were divided into 4 groups based on re-entry type and blood pressure alteration rate (AR) after acute aortic dissection. After insertion of the stent, the following results were observed: a) AR improved; b) proximal descending aorta and superior mesenteric arterial flows increased; c) cardiac function improved; and d) the dissecting aortic diameter decreased in the presence of pressure gradient group. From these results, insertion of a stent-graft to treat acute aortic dissection was judged to be effective.

Acute Disease↗
PubMed1998

Circadian blood pressure and heart rate profiles in normotensive patients with mild hyperthyroidism.

We investigated the influence of thyroid hormones on the circadian blood pressure (BP) and heart rate (HR) variations in 12 normotensive subjects and 12 normotensive patients with mild hyperthyroidism. BP and HR were monitored every 30 minutes for 48 h, and electrocardiograms (ECGs) were recorded to measure the RR interval of the ECGs. We analyzed the circadian BP and HR variations, HR variability, and the morning rise in BP and HR. There was no significant difference in the average 24 h BP between groups. HR and pulse pressure were higher in the hyperthyroid group than in the control group. Though the circadian BP pattern was similar in both groups, HR decreased at night in the control group, but not in the hyperthyroid group. Spectrum analysis of the RR interval showed no increase in the high-frequency (HF) component at night in patients with hyperthyroidism. The HR did not show a morning rise in the hyperthyroid group. These findings indicate that the circadian rhythm of HR was not preserved in patients with mild hyperthyroidism. The circadian BP rhythm was similar in normotensive subjects and normotensive patients with mild hyperthyroidism, suggesting that it resulted from factors other than thyroid hormone.

Adult↗
PubMed1997

BIT, an immune antigen receptor-like molecule in the brain.

We previously found a brain-specific glycoprotein in the rat brain. It postnatally increases and is rich in the mature brain. We cloned cDNA of this protein. It is composed of a signal peptide, a V-type immunoglobulin domain, two C1-type immunoglobulin domains, a transmembrane segment and a cytoplasmic region containing two tyrosine-based activation motifs (TAM) that are variants of the antigen receptor signaling motifs. The overall structure is similar to those of immune antigen receptors. This molecule, BIT (brain immunoglobulin-like molecule with TAMs), is a major endogenous substrates of brain tyrosine kinases in vitro. Cerebral cortical neurons could extend their neurites on BIT-coated substrate and anti-BIT monoclonal antibody specifically inhibited the effect. These findings and our recent study concerning BIT signal transduction mechanism suggest that BIT, an immune antigen receptor-like molecule of the brain, functions as a membrane signaling molecule that may participate in cell-cell interaction.

Amino Acid Sequence↗