Search PubMed⌕ Search

Biomedical subjects

H Komai

Publications and source records attributed to H Komai.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Lower mid-line skin incision and minimal sternotomy in pediatric open heart surgery--an alternative cosmetic approach].

Full median sternotomy has been the standard approach for open heart surgery. However, it leaves an unsightly surgical scar. We therefore designed a lower mid-line skin incision and minimal sternotomy approach as a cosmetic alternative. Since February 1993, 78 pediatric patients with congenital heart disease have undergone this open heart surgery procedure. Their ages ranged from 1 month to 13 years (median: 2 years and 7 months) and body weights ranged from 2.4 to 43 kg (median: 11.5 kg). Thirty-one patients had atrial septal defect, 34 perimembranous ventricular septal defect, 9 subpulmonary ventricular septal defect, and 4 other cardiac anomalies. All cannulations for cardiopulmonary bypass could be performed through this approach. No patients required conversion to standard median sternotomy and no peri- or postoperative complications related to this approach, such as injury to the great artery and vein, air embolism, or sternal deherence, were noted. This approach is technically easy and an excellent cosmetic approach in pediatric open heart surgery.

Adolescent↗
PubMed1998

[The long-term result of an adult case of transposition of the great arteries corrected with Rastelli operation at the age of thirty-two years].

A 32-year-old woman with transposition of the great arteries was referred to us for corrective surgery. She had severe cyanosis, dyspnea, and hemoptysis. The cardiac catheter study and echocardiography revealed that she had transposition of the great arteries, associated with atrial septal defect, ventricular septal defect, patent ductus arteriosus, and pulmonary stenosis. Rastelli operation was performed using equine pericardial roll with three valves made from autologous pericardium. After the operation she gave birth to two children without any symptom. Ventricular tachycardia occurred several times but was controlled by the drug. Eight years after the operation she underwent catheter study. Although the right ventricular pressure was 80 mmHg and the pressure gradient through the conduit was 38 mmHg, her general clinical condition was fairly good. We think the late postoperative result of this patient is satisfactory as an adult case of transposition of the great arteries.

Adult↗
PubMed1998

[Combined coronary artery bypass with right nephrectomy in a patient with left main lesion, calcified ascending aorta, pelvic carcinoma and liver cirrhosis].

A 66-year-old female had ischemic heart disease due to left main lesion complicated with calcified ascending aorta, right pelvic carcinoma and liver cirrhosis. The combined operations with coronary artery bypass by left internal thoracic artery under the hypothermic ventricular fibrillation with cardiopulmonary bypass and right nephrectomy were performed successfully. Postoperatively Treadmill exercise test and scintigram revealed no ischemihc change. She is doing well. The aortocoronary bypass to left anterior descending artery using a left internal thoracic artery under hypothermic ventricular fibrillation with cardiopulmonary bypass might be one of surgical options for high risk patient.

Aged↗
PubMed1997

Surgical strategy for doubly committed subarterial ventricular septal defect with aortic cusp prolapse.

BACKGROUND: Many surgeons recommend early repair of doubly committed subarterial ventricular septal defect regardless of the clinical symptoms. We reviewed our patients of this anomaly with aortic cusp prolapse to justify this strategy. METHODS: We reviewed the preoperative and postoperative records of 27 patients with doubly committed subarterial ventricular septal defect and aortic cusp prolapse. The patients' ages ranged from 2 months to 11 years (median, 4.6 years). RESULTS: During the preoperative observation period, aortic regurgitation (AR) developed in 65% of the patients. In the 8 patients without AR before the operation, AR did not develop after the operation, whereas AR persisted in 12 (63%) of the 19 patients with preoperative AR. To identify the risk factors for persistent AR after the operation we analyzed the data for the patients with preoperative AR in the persistent AR group (n = 12) and eliminated AR group (n = 7) and found a longer period from the onset of AR to the operation in the persistent AR group (32.1 +/- 10.1 versus 5.6 +/- 1.9 months; p = 0.014). During the follow-up period 10 of the 17 patients with mild AR before the operation showed persistent AR in the postoperative period, but it did not progress. CONCLUSIONS: We conclude that early surgical repair with a minimum observation period is essential for prevention of residual AR. Even if a tiny AR is detected preoperatively, the patient should be surgically treated immediately.

Age Factors↗
PubMed1996

An unusual variation of left ventricular-right atrial communication.

We herein present a 5-month-old boy with an infravalvular-type left ventricular-right atrial communication without an abnormal tricuspid valve leaflet. The thick chorda of the anterior tricuspid leaflet was inserted into the upper edge of the ventricular septal defect which was placed just under the commissure. The jet from the septal defect pushed this thick chorda and opened the commissure, which thus caused the abnormal pathway from the left ventricle to the right atrium. This mechanism of left ventricular-right atrial communication has not yet been reported elsewhere.

Heart Atria↗
PubMed1996

Operative technique for persistent left superior vena cava draining into the left atrium.

We applied a surgical method with an inverted flap of the left atrial appendage to construct an internal conduit in a 4-year-old girl with a persistent left superior vena cava draining into the left atrium associated with an atrial septal defect. The remaining defect of the septum was closed with autologous pericardium. The short-term result is satisfactory, although the long-term result remains to be ascertained.

Cardiac Surgical Procedures↗
PubMed1996

Lack of inhibition by inhalational anesthetics of myocardial contraction dependent on intracellular sodium activity.

BACKGROUND: When cardiac muscle is stimulated at a high frequency after rest, the peak force increases rapidly at first and then slowly. The slow phase reflects Ca2+ accumulation dependent on an increase in intracellular Na+ activity. The positive inotropic effect of high concentrations of cardiac glycosides also involves Ca2+ accumulation dependent on an increase in intracellular Na+ activity. The effect of isoflurane on the component of myocardial contraction dependent on an increase in intracellular Na+ activity is not well understood. METHODS: The isometric force of rabbit papillary muscle contractions was measured. The authors studied the effects of isoflurane on the force increase that occurs when the muscles are stimulated after a rest and on the force increase induced by ouabain. RESULTS: Isoflurane (1.5%, 2.4%) had no statistically significant effect on the magnitude of the slow phase of force increase when the muscles were stimulated at 2 Hz after a rest. Isoflurane (1.5%) did not decrease the magnitude of force increase induced by ouabain (1 microM). CONCLUSIONS: Isoflurane has little effect on myocardial contractions that depend on Ca2+ accumulation after an increase in intracellular Na+ activity. This may partly account for the smaller cardiac depressant effect of isoflurane observed at high frequencies rather than at low frequencies. The results of the present study and an earlier study with halothane suggest that the lack of inhibition of contractions dependent on Ca2+ accumulation after an increase in intracellular Na+ activity may be a common property of inhalational anesthetics.

Anesthetics, Inhalation↗
PubMed1996

Thrombomodulin and angiotensin-converting enzyme activity during pediatric open heart operations.

BACKGROUND: Thrombomodulin and angiotensin-converting enzyme are endothelial glycoproteins. The metabolism of these substances is altered when endothelial cells are damaged. METHODS: Serum thrombomodulin level was assayed in 56 children and angiotensin-converting enzyme activity determined in 27 children with congenital heart disease before, during, and after open heart operations. RESULTS: The thrombomodulin level was significantly higher in children with a high pulmonary blood flow who had pulmonary hypertension than in those with a normal pressure (p < 0.01), and although all patients showed an increase in serum thrombomodulin after coming off cardiopulmonary bypass, the increase was greater in those with preoperative pulmonary hypertension (p < 0.05). Serum angiotensin-converting enzyme activity was normal preoperatively in all children, irrespective of pulmonary arterial pressure, and decreased in all after coming off cardiopulmonary bypass but decreased to a significantly greater extent in those who had pulmonary hypertension preoperatively (p < 0.05). CONCLUSIONS: These findings are compatible with the presence of pulmonary endothelial cell injury and dysfunction before intracardiac repair, which is exacerbated by cardiopulmonary bypass.

Adolescent↗
PubMed1996

[Pulmonary artery banding using expanded polytetrafluoroethylene suture].

Pulmonary artery banding (PAB) is essential for infants of complicated cardiac anomaly without pulmonary stenosis, especially those who require future Fontan type correction. In order to avoid pulmonary artery branch stenosis or uneven growth we utilize expanded polytetrafluoroethylene (E-PTFE) suture (Gore-Tex suture, CV-0) as a banding material. We performed three PABs (two newborns and one infant) with this suture. All children were doing well after the banding and no one revealed residual pulmonary hypertension or pulmonary artery distortion in the postoperative catheter study. One patient successfully underwent total cavopulmonary connection eight months after PAB. We believe E-PTFE suture is an advantageous material of PAB for newborns and young infants.

Female↗
PubMed1995

Procaine enhancement of the rapid cooling contracture and inhibition of the decay of potentiated state in rabbit papillary muscle.

We tested the possibility that inhibition of Ca2+ release from the sarcoplasmic reticulum decreases the transsarcolemmal Ca2+ efflux and results in an increased sarcoplasmic reticulum Ca2+ content. We used procaine to inhibit sarcoplasmic reticulum Ca2+ release in rabbit papillary muscles. Rapid cooling-induced contractures were used as an index of sarcoplasmic reticulum Ca2+ content. Decay of potentiated state was measured to study whether the transsarcolemmal Ca2+ efflux is decreased in the presence of procaine. Procaine (0.5, 1.0 mM) inhibited contractions elicited by electrical stimulation and enhanced the rapid cooling-induced contracture. The initial decay of potentiated state that occurs when the muscle was stimulated at a low frequency was slowed in the presence of procaine. These results suggest that procaine inhibition of Ca(2+)-induced release of sarcoplasmic reticulum Ca2+ decreases the transsarcolemmal Ca2+ efflux relative to the influx, resulting in an increased sarcoplasmic reticulum Ca2+ content.

Animals↗
PubMed1995

Maturation of the contractile response and its endothelial modulation in newborn porcine intrapulmonary arteries.

Pulmonary vascular reactivity is thought to be greater in the newborn than adult lung. To determine the influence of the endothelium on smooth muscle cell contractility, responses of rings of isolated intrapulmonary arteries were studied from pigs at birth aged < 2 h, 2 d, 3 d, and 10 d (n = 4 per age group) and from eight adult animals. At birth, the response to KCl (25 mM) and prostaglandin F2 alpha (PGF2 alpha) (3 microM) but not histamine (0.1 mM) was greater in rings with endothelium (E+) than without (E-). The response to PGF2 alpha decreased between birth and 3 d by which time the contraction was less in E+ rings than E-, but L-nitro monomethyl arginine augmented contraction at all ages. In the immature piglets, the response to phenylephrine was less in E+ rings than E-, an effect which was reversed by L-N omega-nitro-L-arginine methyl ester. The response to all contractile agonists increased between 10 d and adulthood. The concentration of plasma endothelin-1 was determined in all animals by RIA and was higher at birth than at 3 d or later. In summary, 1) at birth, endothelium enhanced contractility, when plasma endothelin was greatest, but released NO in the presence of phenylephrine and PGF2 alpha; 2) contractile response to all agonists was small at birth; and 3) a complex interaction existed between the contractile agonist and the effect of endothelial maturation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Prevention of lung injury during open heart operations for congenital heart defects.

To elucidate free radical-induced lung injury associated with open heart operations for congenital heart defects, we studied 23 such patients. Maximum plasma chemiluminescence level (a marker of peroxylipids) in patients with pulmonary hypertension (n = 8) was higher than in patients with cyanotic disease (n = 8) (1,115.4 +/- 189.9 versus 728.8 +/- 48.3 counts; p < 0.05). There was a significant correlation between the maximum chemiluminescence level and preoperative pulmonary to systemic arterial pressure ratio (r = 0.929; p < 0.05). To investigate the effect of allogeneic leukocytes, we compared pulmonary hypertensive patients without allogeneic leukocyte transfusion during operation (n = 7) with the group with pulmonary hypertension. Both maximum chemiluminescence level during bypass (712.4 +/- 24.9 versus 1,115.4 +/- 189.9 counts; p < 0.05) and percent decrease in pulmonary arterial pressure after bypass (44.7% +/- 6.2% versus 28.2% +/- 4.5%; p < 0.05) were significantly improved, suggesting that depletion of leukocytes decreased the lung injury induced by free radical reaction.

Adolescent↗
PubMed1994

Effect of cardiopulmonary bypass on the circulating level of soluble GMP-140.

Soluble GMP-140 can prevent the adhesion of activated neutrophils to endothelium in vitro. Because cardiopulmonary bypass causes neutrophil-endothelial interaction, the plasma level of soluble GMP-140 was measured using an enzyme immunoassay system in 32 children undergoing intracardiac repair of congenital heart disease. They had either a high, low, or normal pulmonary blood flow (n = 13, 12, and 7 respectively). Because activated platelets are a source of GMP-140, the plasma beta-thromboglobulin level was also measured. Blood was sampled before, during, and for 24 hours after cardiopulmonary bypass. Plasma levels of both soluble GMP-140 and beta-thromboglobulin increased after the onset of cardiopulmonary bypass in all patients but for both substances the increase was greater in those with a low pulmonary blood flow (p < 0.05 for all comparisons). The sum total of soluble GMP-140 values during and after operation was correlated negatively with the preoperative mean pulmonary arterial pressure (p < 0.05 for all time intervals). GMP-140 level correlated with the plasma beta-thromboglobulin level (r = 0.5, p < 0.05). This work supports the contention that soluble GMP-140 is released from activated platelets during cardiopulmonary bypass, the level being particularly high in those who had intrinsically abnormal platelets preoperatively in association with a low pulmonary blood flow. Patients with a high pulmonary blood flow, who are more susceptible to endothelial cell injury, may be less well protected by soluble GMP-140.

Adolescent↗
PubMed1994

Effect of thiopental on Ca2+ release from sarcoplasmic reticulum in intact myocardium.

BACKGROUND: While thiopental is known to inhibit the myocardial transsarcolemmal influx of Ca2+, the effect of thiopental on sarcoplasmic reticular Ca2+ release has not been characterized. METHODS: Isolated papillary muscles of rabbits were used. We measured postrest contractions to assess the Ca2+ release by sarcoplasmic reticulum in response to electrical stimulation. Contractures induced by rapid cooling were used as an index of Ca2+ content of sarcoplasmic reticulum. The effect of thiopental on the availability of extracellularly derived Ca2+ was evaluated from measurements of contractions at 0.1 Hz in the presence of 1 microM ryanodine. RESULTS: Thiopental sodium (10, 20, and 30 mg/l; 38, 76, and 113 microM) inhibited the postrest contraction but not the contracture induced by rapid cooling. In the presence ryanodine, thiopental inhibited the postrest contraction elicited after 10 s of rest after 2-Hz stimulation much less than the steady-state contraction at 0.1 Hz (beat interval 10 s). Thiopental inhibited the postrest contraction (no ryanodine present) more strongly than did Ni2+ (an inhibitor of the transsarcolemmal Ca2+ influx) when the contraction at 0.1 Hz in the presence of ryanodine was inhibited to the same extent. CONCLUSIONS: These results suggest that thiopental decreases sarcoplasmic reticulum Ca2+ release induced by electrical stimulation and inhibits the ryanodine-induced efflux of sarcoplasmic reticulum Ca2+.

Animals↗
PubMed1994

Donor lung preservation: effect of cold preservation fluids on cultured pulmonary endothelial cells.

Pulmonary arterial (PA) endothelial cell morphology changes during cold preservation. In the present study, the efficacy of University of Wisconsin solution (UW), UW solution without colloid (modified UW), Euro-Collins (EC), Marshall's solution (MS), and medium 199 + 10% fetal calf serum [culture medium (CM)] in maintaining and regaining the cytoskeleton of cultured porcine PA endothelial cells kept at 4 degrees C and then rewarmed was compared. Features studied were actin, microtubules, vinculin, and talin, using immunofluorescence, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and immunoblotting; permeability of the cell sheet; wound healing; and phagocytic capacity. When cooled, microtubules depolymerized in all fluids but EC and MS reduced depolymerization of actin. Permeability decreased at 4 degrees C (P < 0.05), and wound healing and phagocytosis ceased. When rewarmed after EC, UW, and CM preservation, wound healing and phagocytosis started within 15 min and proceeded normally. Permeability returned to normal but was excessive following UW preservation. Microtubule repolymerization was fastest following UW preservation, and actin filament repolymerization was fastest after EC preservation. Thus the type of preservation fluid used influenced the rate of loss and recovery of specific cytoskeletal components, with EC giving the fastest structural and functional recovery.

Adenosine↗
PubMed1994

[Sarcoplasmic reticular calcium release and myocardial protection--effect of ryanodine on myocardial ischemia and reperfusion-induced injury].

Calcium release from sarcoplasmic reticulum (SR) may contribute to the intracellular calcium overload observed during myocardial ischemia and reperfusion. We have therefore investigated the ability of ryanodine to enhance myocardial protection when given before ischemia or during reperfusion in the isolated working rat heart. Hearts (n = 6-9/group) from male Wistar rats were aerobically (37 degrees C) perfused (20 min) with bicarbonate buffer (Ca2+ = 2.4 mM). In the first series of studies, this was followed by a 3 min infusion of St Thomas' Hospital cardioplegic solution containing various concentrations of ryanodine. Hearts were then subjected to 38 min of normothermic (37 degrees C) global ischemia and 35 min of reperfusion (15 min Langendorff, 20 min working). The recoveries of aortic flow (%AF) were 50.3 +/- 2.5% in the ryanodine free controls versus 55.2 +/- 5.8, 72.0 +/- 1.3 (p < 0.05), 61.0 +/- 4.3, 51.8 +/- 5.1 and 32.1 +/- 5.0 (p < 0.05)% in the 0.88, 1.75, 2.13, 2.50 and 10.00 nM ryanodine groups, respectively. Creatine kinase (CK) leakage during Langendorff reperfusion was reduced in the 1.75 nM group but was similar to control in all other groups. In the second series of studies, 3 min of cardioplegia without ryanodine and 38 min of ischemia (37 degrees C) were followed by 15 min of Langendorff reperfusion with 0, 0.09, 0.18, 0.88 or 1.75 nM ryanodine, %AF was 59.3 +/- 3.3%, 54.7 +/- 3.3, 53.8 +/- 3.5, 38.4 +/- 8.9 (p < 0.05) and 33.3 +/- 5.8 (p < 0.05)% in the 0, 0.09, 0.18, 0.88 and 1.75 nM ryanodine groups, respectively. CK leakage tended to increase dose-dependently.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

A surgical procedure for the prevention of complete right bundle branch block following total correction of tetralogy of Fallot.

Complete right bundle branch block (CRBBB) has been reported as the most common sequelae following total correction of tetralogy of Fallot. A review of previous reports and our own experience have led us to believe that it may be related to the fatal ventricular dysrhythmias which often occur during the postoperative follow-up period. Therefore, we have been trying to reduce the incidence of CRBBB, and we describe herein our surgical procedure for the prevention of CRBBB and its results. Of a total 28 consecutive patients who underwent intracardiac repair by this procedure, only 4 (14%) developed surgically induced CRBBB, none of whom developed a left anterior hemiblock. At the time of this report, no severe ventricular arrhythmias have been found in this series during the postoperative follow-up period. These results suggest that our operative procedure is feasible for the prevention of CRBBB. With regard to the relationship between ventricular dysrhythmia and CRBBB, careful observation is necessary throughout the patients' lifetime.

Adolescent↗