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Biomedical subjects

S Eguchi

Publications and source records attributed to S Eguchi.

At least 217 records · Page 12Linked to original sources

Mechanical circulatory assist using heparin-coated tube and roller pump system.

We have invented a mechanical circulatory assist system that uses a heparin-coated tube and a roller pump. Experimental left heart bypass was performed on 13 mongrel dogs for 24 hours without systemic heparinization. There were no significant changes in coagulation variables during the experiment, and pathological examination of internal organs after bypass revealed no evidence of thromboembolism. We applied this assist system to 13 patients who could not be weaned from cardiopulmonary bypass after an open heart operation. Left heart bypass was performed on 7 patients, right heart bypass on 1 patient, combined left and right heart bypass on 2, and venoarterial bypass without oxygenation on 3. Duration of support ranged from 5 hours to 21 days, and the pump flow rate ranged from 0.8 to 3.2 L/min. Eight patients were successfully weaned from this support, and 6 were discharged from the hospital. Examination of the tubes in the assist system revealed excellent antithrombogenicity for at least 3 days without systemic heparinization. There was no evidence of thromboembolism in brain, kidneys, lungs, or other organs. Because of its simplicity and antithrombogenicity, this mechanical assist system is beneficial for patients who cannot be weaned from cardiopulmonary bypass after open heart operations.

Adult↗

Limited vertical skin incision for median sternotomy.

The cosmetic deformity of the vertical skin incision for median sternotomy was decreased by using a mechanical traction system to increase exposure at the superior margin of a shorter wound. The limited vertical skin incision did not impede technical surgical maneuvers and produced a scar that was more acceptable than submammary incision or right anterior thoracotomy. The limited skin incision is especially useful in young women with congenital heart disease.

Adolescent↗

Myocardial protection of neonatal heart by cardioplegic solution with recombinant human superoxide dismutase.

The effectiveness of high-potassium cardioplegic solution in the neonatal heart remains controversial. Our previous study indicated that the protection afforded by a cardioplegic solution was inadequate in the neonatal heart. On the hypothesis that oxyradicals were responsible for the ineffectiveness of cardioplegic solution in neonatal heart, the effects of a cardioplegic solution (a modified St. Thomas' Hospital cardioplegic solution) with recombinant human superoxide dismutase on the isolated perfused neonatal guinea pig hearts (within 2 days after delivery, body weight of 60 to 120 g) were studied in comparison with those on the adult hearts (6 to 8 weeks after delivery, body weight of 300 to 500 g). After arrest induced by modified St. Thomas' Hospital cardioplegic solution, hearts were subjected to 120 min of ischemia at 20 degrees C, during which time the cardioplegic solution was injected every 30 minutes. Then the heart was reperfused for 60 minutes at 37 degrees C. Under this condition, the left ventricular developed pressure recovered to 84.4% +/- 4.0% of the preischemic value in the adult heart, whereas the recovery was only 68.1% +/- 3.1% in the neonatal heart. Thiobarbituric acid-reactive substance level, a parameter of lipid peroxidation by oxyradicals, significantly increased during ischemic arrest both in the adult and neonatal heart. However, the increase was much greater in the neonatal heart than in the adult. Cardioplegia with recombinant human superoxide dismutase (300 and 1,000 U/mL) significantly inhibited this accumulation of thiobarbituric acid-reactive substance in the neonatal heart; at 1,000 U/mL, the myocardial function of the reperfused neonatal heart recovered to the level of the adult heart.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗

L-arginine infusion induces hypotension and diuresis/natriuresis with concomitant increased urinary excretion of nitrite/nitrate and cyclic GMP in humans.

1. The vascular endothelium produces endothelium-derived relaxing factor (EDRF) or nitric oxide (NO), which exerts vasodilation through cyclic guanosine monophosphate (cGMP) as a second messenger. To determine whether EDRF has any vasodilating and natriuretic action in man, the present study examined the effects of L-arginine (L-Arg), a substrate for NO, on the responses of mean blood pressure (MBP) and heart rate (HR); plasma concentrations of cGMP, atrial natriuretic factor (ANF) and nitrite/nitrate (NOx); urinary excretion of sodium, cGMP and NOx; and urinary flow in eight normal male subjects. These parameters were compared with those following saline infusion in the same subjects. Clearance of para-aminohippuric acid (PAH) and inulin was studied in five normal subjects. 2. Infusion of L-Arg (30 g) caused a significant fall in MBP (-8 mmHg) with a concomitant rise in HR (10 beats/min), while saline infusion had no effects on these parameters. 3. Neither L-Arg nor saline infusion caused appreciable changes in plasma concentrations of ANF or NOx. Plasma cGMP concentrations increased significantly during (1.7-fold) and after (1.9-fold) L-Arg infusion, but only slightly (1.3-fold) during saline infusion. 4. Urine flow increased more remarkably following L-Arg infusion than that following saline infusion. Remarkable increases in urinary excretion of sodium and fractional excretion of sodium were observed after L-Arg infusion compared with those after saline infusion. Natriuresis was associated with enhanced urinary excretion of cGMP and Nox. Urinary Nox excretion showed positive correlations with urinary flow (r = 0.69, P less than 0.001) and with urinary cGMP excretion (r = 0.60, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Mechanical circulatory assist by a roller pump system using hydrophilic heparinized polymer coated tubing.

We developed a circulatory assist system driven by a roller pump using hydrophilic heparinized polymer coated tubing. This system is easy to handle and does not require systemic heparinization. We applied it to 11 patients who failed to be weaned from cardiopulmonary bypass after open heart surgery. Left heart bypass was employed in 5 patients, right heart bypass in 1, combined left and right heart bypass in 2, and venoarterial bypass without oxygenation was done in 3 patients. The assisting flow rate ranged from 0.8 to 3.2 L/min, and the duration of the assist ranged from 5 h to 21 days. Six patients were weaned from this support, and 5 were discharged from the hospital. This system is beneficial for patients who failed to wean from cardiopulmonary bypass after cardiac surgery because of its simplicity and antithrombogenicity.

Aged↗

Synthesis and release of endothelin-1 by human decidual cells.

We have studied whether a novel vasoconstrictor, endothelin-1 (ET-1), is synthesized by and released from human decidual cells in early pregnancy, and whether ET-1 acts directly on their own cells. It was observed that ET-1-like immunoreactivity (ET-1-LI) was released from cultured decidual, but not villous, cells, as a function of time. Reverse-phase high-pressure liquid chromatography of the conditioned media from the decidual cells revealed a major peak of ET-1-LI coeluting with standard ET-1. Phorbol myristate acetate, a protein kinase C activator, dose-dependently increased the release of ET-1-LI from the decidual cells, while a protein kinase C inhibitor, H7, significantly attenuated the stimulatory effect of phorbol myristate acetate on ET-1-LI release. Northern blot analysis demonstrated the expression of messenger RNA for prepro-ET-1 in the decidual tissue, but no such messenger RNA was observed in the villous tissue. The human decidual tissue contained a noninteracting, single class of binding sites demonstrating higher affinity for ET-1 and ET-2 than ET-3. This would be most consistent with the ETA receptor subtype. An ET-1-induced, dose-dependent accumulation of total inositol phosphates was also observed in human decidual cells prelabeled with myo-[3H]inositol. The present results demonstrate for the first time that human decidual cells in early pregnancy can synthesize and release ET-1. These cells also possess specific functional receptors for ET-1 which are coupled to phosphoinositide hydrolysis. Thus our data suggest a possible role for ET-1 in autocrine and/or paracrine function in human decidual cells.

Binding, Competitive↗

Direct effect of endothelin-1 on the granuloma cells of the porcine ovary.

Specific binding sites for endothelin-1 (ET-1), a novel potent vasoconstrictor peptide, as well as the effects of ET-1 on cytosolic free Ca2+ concentration ([Ca2+]i), intracellular total inositol phosphate (IP) generation and steroidogenesis were studied in cultured porcine granulosa cells. Scatchard analysis of a binding study using 125I-labelled ET-1 indicated the presence of a single class of high-affinity binding sites with almost equal affinity for ET-1 and ET-3: the apparent dissociation constant was 0.59 nmol/l and the maximal binding capacity was 1.84 pmol/mg protein. Affinity-labelling of 125I-labelled ET-1 to the membranes using disuccinimidyl tartarate as a cross-linker revealed one major and one minor band with the apparent molecular weights of 32 kDa and 49 kDa respectively. ET-1 dose-dependently (1-100 nmol/l) induced rapid and transient increases in [Ca2+]i in fura-2-labelled cells. ET-1 also dose-dependently stimulated total IPs in cells prelabelled with myo-[3H]inositol. ET-1 had a slight stimulatory effect on the secretion of progesterone but not of oestradiol from porcine granulosa cells. The present data clearly demonstrate the presence of a non-selective ET receptor (ETB) in porcine granulosa cells coupled with phosphoinositide hydrolysis and [Ca2+]i mobilization, and suggest that ET-1 may play some role in the production of progesterone by porcine granulosa cells.

Animals↗

Effects of manidipine on DNA and protein syntheses in cultured vascular smooth muscle and endothelial cells and on proto-oncogene expression.

To elucidate the importance of Ca2+ influx via voltage-dependent Ca2+ channels in the mechanism of vascular remodeling, we investigated effects of a new Ca2+ channel blocker manidipine on DNA and protein syntheses stimulated by several mitogens in cultured rat vascular smooth muscle cells (VSMC) and bovine endothelial cells (EC), and growth-related immediate early proto-oncogenes expression in VSMC. Endothelin-1 (ET-1) induced receptor-mediated phosphoinositide breakdown and increased cytosolic free Ca2+ levels in rat VSMC, with concomitant increases in proto-oncogenes (c-fos c-myc) mRNA levels as well as DNA and protein syntheses. Manidipine dose-dependently (10(-9) M to 10(-6) M) inhibited DNA, and protein syntheses stimulated by 10(-7) M ET-1 in rat VSMC; manidipine was a more potent inhibitor for protein synthesis (IC50: 10(-8) M) than for DNA synthesis (IC50: 10(-7) M). Manidipine also inhibited DNA synthesis stimulated by 10 ng/mL bFGF and 2.5% FCS in rat VSMC and bovine EC; manidipine was more potent in inhibiting DNA synthesis stimulated by bFGF than that by FCS in both cells. The expression of ET-1-induced c-fos and c-myc mRNAs levels was unaffected by manidipine. These results suggest that manidipine has potent inhibitory effects on the ET-1-induced hyperplasia and/or hypertrophy of VSMC, as well as on the bFGF-induced hyperplasias of VSMC and EC, thus implicating its potential usefulness for preventing abnormal VSMC proliferation and angiogenesis associated with hypertension and atherosclerosis.

Animals↗

Effect of human recombinant erythropoietin on reduction of homologous blood transfusion in open-heart surgery. A Japanese Multicenter study.

BACKGROUND: Recombinant human erythropoietin (EPOCH) has been shown to increase erythropoiesis; therefore, EPOCH has been used in conjunction with autologous blood predonation (ABP) before surgery. However, the administration methods of EPOCH to obtain an adequate volume of ABP before open-heart surgery have not been determined. METHODS AND RESULTS: The effects of EPOCH on harvesting ABP and decreasing homologous blood transfusion (HBT) in open-heart surgery were examined prospectively in 205 patients treated in a 29-institute multicenter study. Single dose of 3,000, 6,000, or 9,000 IU of EPOCH were administered for 2 weeks (two or three times per week) without ABP (group 1, n = 69) or for 3 weeks (two or three times per week) with ABP (group 2, n = 97) and compared with control subjects (n = 39). Preoperative blood hemoglobin increase (delta Hb[g/dl]) was < 1.0 g/dl in group 1. When EPOCH was given three times a week, the delta Hb in each subgroup of group 2 was 0.6 +/- 1.1 (control), 2.1 +/- 1.3 (3,000 IU), 2.4 +/- 1.4 (6,000 IU), and 2.8 +/- 1.5 (9,000 IU), which was significantly higher than the control (p < 0.05) and was dose dependent. The HBT rates in patients with a moderate perioperative blood loss of between 15 and 50 ml/kg were 75.0% (control), 35.7% (3,000 IU), 52.9% (6,000 IU), and 66.7% (9,000 IU) in group 1, and respective volumes in group 2 were 40.0% (control), 20.0% (3,000 IU), 26.9% (6,000 IU), and 12.5% (9,000 IU). The overall HBT rate of EPOCH-treated patients with a moderate blood loss was 50% (20 of 40) in group 1 and 21% (13 of 62) in group 2. The HBT rate was significantly reduced by combination of preoperative EPOCH treatment (three times per week) and ABP (p < 0.0001). CONCLUSIONS: Dose-dependent increase of blood hemoglobin level was observed by EPOCH treatment with ABP; combination of EPOCH treatment and ABP can reduce HBT during open-heart surgery.

Blood Transfusion↗

[Late postoperative outcome of plastic operation versus valve replacement for mitral regurgitation].

Between January 1980 and August 1991, 99 patients underwent operation for mitral valve regurgitation (MR). The ages of the patients ranged from 12 to 67 years, (49.4 +/- 11.9 years), and there were 39 males and 60 females. Pathological cause of regurgitation, which was determined by intraoperative inspection and histological findings of excised leaflets, was rheumatic in 46, degenerative in 38, infective endocarditis in 9, ischemic in 4 and unknown in 2 patients. Cardiac rhythm was atrial fibrillation in 73, normal sinus rhythm in 24 and junctional rhythm in 2 patients. Our principles for valve repair were (1) excision of responsible segment and repair for prolapsed leaflet due to torn chordae, (2) shortening of elongated chordae, (3) annuloplasty, and (4) repair of perforated leaflet. Finally, 19 patients endured plastic operation, and 80 patients underwent prosthetic valve replacement. The rate of plastic procedure was 62.5% (10/16) in degenerative MR with mural chordal lesions, 42.9% (3/7) in rheumatic MR without stenosis, 22.2% (2/9) in infective endocarditis and 100% (2/2) in MR with unknown etiology. Mitral valve repair was failed both in rheumatic MR associated with stenosis (39 patients) and in ischemic MR (4 patients). A ten-year survival rate after operation was 92.2 +/- 3.1% in patients with valve replacement and 83.6 +/- 10.0% with valve repair (N.S.), and a proportion of event-free survival in patients with valve replacement was similar to valve. Late postoperative cardiac catheterization revealed decreased left ventricular volume indices and increased left ventricular end-systolic stress/volume ratio in both groups compared to preoperative values, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

[Anticoagulant and fibrinolytic therapies for anterior chamber fibrin following cataract surgery in the rabbit eye].

Effects of anticoagulant or fibrinolytic therapy on anterior chamber fibrin following cataract surgery was evaluated. In one series of experiment, various amounts of antithrombin III (ATIII), an anticoagulant, were injected into the anterior chamber of the rabbit eye immediately after phacoemulsification of the lens. In another series, various amounts of tissue plasminogen activator (TPA), a fibrinolytic agent, were injected into the anterior chamber 24 hours after phacoemulsification when it was filled with fibrin. The extent of the fibrin clot was graded using a slit lamp microscope, and the aqueous flare intensity was determined with a laser cell-flare meter for 2 weeks after operation. The eyes treated with TPA was also examined with light and electron microscopy. ATIII showed an inhibitory effect on fibrin formation, but complete inhibition was not obtained even with the highest concentration used. In contrast, the fibrin clot was completely resolved even with the lowest dose of TPA used, while no side effect such as inflammation or bleeding was seen. Histological examinations revealed no pathological changes in eyes treated with TPA. TPA may be a promising agent for fibrin resolution after cataract surgery.

Animals↗

[Surgical management of desmoid tumors of the chest wall: a case report and review of literature].

A 45-year-old man without special predispositions showed a chest wall tumor with tenderness. A needle biopsy revealed a desmoid tumor which had invaded the muscles. A wide resection from the second to fifth rib was carried out and 4 years have passed without recurrence. A resection, at least 3 cm away from the lesion, is necessary for desmoid tumors which seem to have clear margins.

Fibroma↗

[A surgical repair of complete endocardial cushion defect associated with single atrium, persistent left superior vena cava draining into the left atrium, hemiazygos connection and double orifice mitral valve].

Successful surgical repair of a 1-year-old girl of complete endocardial cushion defect associated with single atrium, persistent left superior vena cava draining into the left atrium, hemiazygos connection and double orifice mitral valve was reported. We repaired the endocardial cushion defect by using an endocardial cushion prosthesis and a new atrial septum was created to allow the left superior vena cava draining into the right atrium. We made no treatment for the accessory mitral valve orifice because of no regurgitation.

Azygos Vein↗

[Surgery of vascular rings associated with complex intracardiac anomaly].

Two rare cases with surgically treated vascular ring associated with complex congenital cardiac anomaly are reported. Each case showed vascular ring due to right aortic arch, right descending aorta, aberrant left subclavian artery and left ductus arteriosus. Case 1 was a 2-year-old boy associated with ligamentum arteriosum and total anomalous pulmonary venous connection (TAPVC), and presented dyspnea and dysphagia. Case 2 was a 3-year-old girl associated with patent ductus arteriosus (PDA) and tetralogy of Fallot (TOF). In case 1, the two-staged operation was performed because of the necessity of mechanical ventilation and of recurrent respiratory infection. Division of the ligamentum, dissection of bronchus and esophagus was performed at the first operation through left thoracotomy, and the intracardiac repair of TAPVC was done three months later. In case 2, PDA division and the intracardiac repair of TOF was done simultaneously through median sternotomy because of the mild symptom of vascular ring and technical feasibility. Each case was successfully treated and became completely asymptomatic.

Abnormalities, Multiple↗