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Biomedical subjects

H Kawata

Publications and source records attributed to H Kawata.

At least 91 records · Page 5Linked to original sources

[Reoperation for obstructed extracardiac conduit after Rastelli operation--an autogenous tissue reconstruction (Danielson) method].

Eight patients with a mean age of 13.0 years underwent reoperation for obstructed extracardiac dacron conduit with xenograft valve at a mean of 7 years after Rastelli operation. In two patients, infective endocarditis of the stenotic conduit was the main indication for the reoperation. Diagnoses included 3 tetralogy of Fallot with pulmonary atresia, 3 d-TGA (III), 1 truncus arteriosus, and 1 corrected TGA. The conduit was completely excised leaving the posterior half of the autogenous external peel of conduit as the new outflow bed and a monocusped patch was then placed. Operations were mostly carried out allowing the heart to continue to beat. One patient with c-TGA who underwent concomitant replacement of aortic and left A-V values died in the hospital 4 months postoperatively. In other 7 patients, systolic pressure gradient across the right ventricular outflow decreased from a mean of 80.3 mmHg to 16.0 mmHg. Postoperative pulmonary regurgitation by UCG were trivial in 3 and grade III in 3 patients. One patient required re-reoperation late postoperatively for re-stenosis due to contracture of Golaski outflow patch. Three patients did not require any homologous blood during either the operation or the rest of the hospital stay. The results suggests that this method is a simple and effective option for reoperation of obstructed extracardiac dacron conduits late after Rastelli operation.

Adolescent↗

[Necrotizing tracheobronchitis following radical repair in tetralogy of Fallot with absent pulmonary valve--a case report].

A 3-month-old infant with tetralogy of Fallot and absent pulmonary valve developed necrotizing tracheobronchitis following a radical repair. Right ventricular reconstruction using an equine pericardial valved conduit and plication of the main pulmonary arteries relieved compression of the left main bronchus by the dilated pulmonary artery. However, respiratory distress increased when bronchitis developed. Eventually, both main stem bronchi became stenotic secondary to inflammation, and the patient died 154 days following surgery. Necrotizing tracheobronchitis is a potentially lethal complication in patients with tetralogy of Fallot and absent pulmonary valve.

Bronchitis↗

Nitroglycerin improves functional recovery of neonatal lamb hearts after 2 hours of cold ischemia.

BACKGROUND: Vascular events during initial reperfusion after a period of hypothermic cardioplegic ischemia may play an important role in the recovery of mechanical function. Prior studies have shown (1) that dysfunction of the postischemic myocardium after normothermic ischemia can be ameliorated by vasodilation and (2) that endothelial dysfunction in the coronary bed and mechanical dysfunction were correlated after hypothermic ischemia. The present study was undertaken to further explore the relation between vascular events during reperfusion and the recovery of mechanical function after hypothermic ischemia by the infusion of the endothelium-independent vasodilator nitroglycerin during reperfusion. METHODS AND RESULTS: We assessed the effect of an infusion of nitroglycerin on the recovery of isolated blood-perfused neonatal lamb hearts arrested for 2 hours with 15 degrees C K+ cardioplegic solution, comparing 8 hearts receiving a nitroglycerin infusion with 9 control hearts. After 30 minutes of reperfusion, nitroglycerin-infused hearts compared with control hearts had better percent recovery of maximum left ventricular developed pressure (83.5 +/- 8.1% vs 73.6 +/- 8.9%, mean +/- SD), left ventricular dP/dt (77.2 +/- 7.7% vs 67.4 +/- 10.3%), coronary blood flow (141.2 +/- 30.6% vs 84.4 +/- 10.4%), and myocardial oxygen consumption (100.7 +/- 51.3% vs 71.2 +/- 18.6%), (all except myocardial oxygen consumption with P < .05). In each heart, we also tested the coronary vascular resistance response to 10(-6) mol/L acetylcholine infusion to assess endothelial function. The recovery of the coronary vascular resistance response to acetylcholine was reduced after reperfusion in both groups compared with the preischemic response to acetylcholine (nitroglycerin, 14.9 +/- 53.8%; control, 13.4 +/- 38.3%). CONCLUSIONS: These results suggest that the effects of hypothermia and reperfusion on recovery of mechanical function after hypothermic ischemia can be offset by an infusion of nitroglycerin. Vasospasm secondary to endothelial dysfunction may play an important role in cardiac recovery after hypothermic ischemia.

Animals↗

[Reconstruction of the pulmonary outflow tract without prosthetic conduit for correction of tetralogy of Fallot with pulmonary atresia].

We reconstructed right ventricular outflow tract without prosthetic conduit for 2 year 11 month and 59 day old Tetralogy of Fallot with pulmonary atresia patients. Left appendage anastomosed between pulmonary trunk and right ventricle was utilized as the posterior wall of the tract. Pericardial patch covered the tract the beneficial methods for patients with Tetralogy of Fallot with pulmonary atresia to avoid late postoperative deleterious complications of prosthetic conduit.

Cardiac Surgical Procedures↗

Non-radioisotope labelling of DNA with multifunctional labelling agent.

A novel bi-functional fluorescent labelling agent derived from 5-hydroxy-1-naphthalene sulfonic acid and tris(2-amino-ethyl)amine was prepared and incorporated to 5'-monophosphate function of DNA through phosphoramidate bond. The labelling agent was designed to bear fluorescent moiety as well as primary and tertiary amines which are expected to have positive charge at neutral pH range. A 15-mer DNA labelled with this reagent exhibited enhanced duplex forming ability with its complement compared to the corresponding un-labelled DNA.

Chromatography, High Pressure Liquid↗

Recovery of cerebral blood flow and energy state in piglets after hypothermic circulatory arrest versus recovery after low-flow bypass.

A miniature piglet model that replicates clinical hypothermic (14 degrees C nasopharyngeal) circulatory arrest and low-flow (50 ml/kg per minute) bypass was used to study carotid blood flow with electromagnetic flow probe, cerebral blood flow by microsphere injection, cerebral metabolic rate by arteriovenous oxygen and glucose extractions, lactate production by cerebral arteriovenous difference, and cerebral edema. Data from five animals that underwent circulatory arrest and five animals that underwent low-flow bypass (aged 28.8 +/- 0.4 [mean +/- standard error of the mean] days) were analyzed. The duration of circulatory arrest and low-flow bypass was 1 hour. In a parallel study with the same animal model, phosphorus 31 magnetic resonance spectroscopy was used to assess cerebral phosphocreatine, nucleoside triphosphate (adenosine triphosphate), and intracellular pH. Five animals (aged 31.8 +/- 1.1 days) underwent circulatory arrest, and five underwent low-flow bypass. A brief phase of hyperemic carotid blood flow was seen immediately after the onset of reperfusion in the circulatory arrest group but not in the low-flow group. In the circulatory arrest and low-flow bypass groups, cerebral blood flow (percentage of baseline 71.2% +/- 8.3% and 69.1% +/- 5.8%, respectively), cerebral oxygen consumption (45.6% +/- 10.0%, 44.5% +/- 7.6%), and cerebral glucose consumption (31.5% +/- 30.7%, 83.5% +/- 24.2%) remained depressed after 45 minutes of reperfusion and rewarming to normothermia. However, after 3 more hours of pulsatile normothermic reperfusion, cerebral oxygen consumption and cerebral glucose consumption had returned to baseline. Phosphocreatine, adenosine triphosphate, and pH were maintained at or above baseline levels throughout low-flow bypass and throughout 3 hours of normothermic reperfusion. In contrast, both phosphocreatine and adenosine triphosphate became undetectable 32 +/- 3.7 minutes after onset of circulatory arrest. During and early after circulatory arrest, pH decreased to a minimum of 6.506 +/- 0.129 at 40 minutes after reperfusion. After 3 hours of normothermic reperfusion, phosphocreatine and adenosine triphosphate recovered to 98.6% +/- 9.0% and 90.1% +/- 13.5% of baseline, respectively, and pH was 7.087 +/- 0.051, similar to baseline (7.1755 +/- 0.041). In the low-flow bypass group, the disparity between the depressed level of cerebral oxygen consumption and normal high-energy phosphate levels may reflect incomplete cerebral rewarming or decreased energy consumption. In the circulatory arrest group, the parallel recovery of oxygen consumption and high-energy phosphates eventually achieving baseline levels suggests that the degree of hypothermia used provides adequate protection for acute cerebral recovery after 1 hour of circulatory arrest.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Triphosphate↗

Effect of calcium and preischemic hypothermia on recovery of myocardial function after cardioplegic ischemia in neonatal lambs.

Hypothermia has been reported to increase intracellular ionized calcium, which may aggravate injury resulting from ischemia and reperfusion. The effects of plasma ionized calcium concentration ([Ca2+]) during hypothermic perfusion on recovery after 2 hours of cold cardioplegic ischemia were evaluated in 32 isolated, blood-perfused neonatal lamb hearts. Three groups of hearts (B, C, and D) were perfusion-cooled for 10 minutes to a myocardial temperature of 17 degrees C and then arrested with St. Thomas' Hospital cardioplegic solution. Group A had 10 minutes of normothermic perfusion before cardioplegia. Group B had cooling with normal [Ca2+]. Group C had citrate added as cooling was started to lower [Ca2+] (0.26 mmol/L), and it was not normalized until 15 minutes into reperfusion. Group D received citrate plus Ca2+ to give normal [Ca2+] during cooling. Groups B and D showed a significantly reduced recovery (p < 0.05) in left ventricular systolic function (developed pressure and the rate of pressure rise) and diastolic function (stiffness constant) than groups A and C. During preischemic cooling, oxygen consumption per beat and coronary vascular resistance increased significantly in groups B and D, but both oxygen consumption and coronary vascular resistance were significantly lower in group C than in groups B and D so long as [Ca2+] was low. The data show that preischemic hypothermia results in reduced postischemic recovery of function compared with simultaneous induction of cardioplegia and hypothermia. Low [Ca2+] during preischemic hypothermia and early reperfusion offsets this deleterious effect of hypothermia.

Animals↗

Tetanus responses under rapid bath solution change: electrotonic depolarization of transverse tubules may release Ca2+ from sarcoplasmic reticulum of Rana japonica skeletal muscle.

1. Single skeletal muscle fibers were transferred from a normal Ringer solution to Na+ ion free solution, and vice versa, and tetanus responses were recorded immediately after the transfer. 2. Fractional tetanus tension recorded immediately after the displacement from the Na+ ion free solution to normal Ringer solution was dependent on fiber diameter. 3. Diffusion of Na+ ions along the transverse tubules was simulated [apparent diffusion constant was 3.11 x 10(-6) (cm2/s)]. 4. Our results suggest that the electronic spreading of membrane potential, caused by an action potential in the transverse tubules, could release Ca2+ ions from sarcoplasmic reticulum.

Action Potentials↗

An analysis of post-contracture potentiation in frog twitch skeletal muscle.

Post-tetanic potentiation (PTP) was mimicked by post-contracture potentiation (PCP) in the twitch muscle of frog. A marked PCP was observed in small bundles of semitendinosus muscle in tetrodotoxin (TTX)-containing solution under current clamp condition. Contractures were induced by a constant depolarizing current pulse of 1 s every 5 min. Each contracture (C) was preceded and followed by a twitch-corresponding short contracture, T1 and T2, with an interval of 2 s. The ratio of twitch height, T2/T1, was measured and compared under various conditions. In TTX-containing Ringer solution, T2/T1 depended on magnitude of both T and C. When T2/T1 was plotted against C/T1 a quasi-linear relationship was found. The slope of the curve was 0.076 and was found to decrease when the duration of T was increased to 1 s. In TTX-containing solution, addition of 2 mM Ba2+ or 1 mM caffeine potentiated T as well as C but decreased T2/T1 markedly. Similar effects were observed when Na+ was replaced with TEA+ or when bath temperature was lowered from 20 to 8 degrees C. In all cases T2/T1 vs. C/T1 curve was shifted to the left and downwards. It was considered that these results could be attributable to an elevation of the resting Ca2+ concentration in the sarcoplasm. Thus the phenomenon of PCP probably reflects the time course of Ca2+ transients in the conditioning contracture C.

Action Potentials↗

Effect of antibody to leukocyte adhesion molecule CD18 on recovery of neonatal lamb hearts after 2 hours of cold ischemia.

BACKGROUND: Prior studies have shown that leukocytes are important in reperfusion injury after normothermic ischemia, and recently discovered leukocyte adhesion molecules that bind to endothelial ligands may be involved in this process. No studies on the role of leukocyte adhesion molecules in hypothermic ischemia are available. METHODS AND RESULTS: We assessed the effect of preischemic administration of monoclonal antibody to the leukocyte adhesion molecule CD18 on recovery of isolated blood-perfused neonatal lamb hearts arrested for 2 hours with 15 degrees C K+ cardioplegic solution by comparing nine antibody-treated and nine control hearts. At 30 minutes after reperfusion, antibody-treated hearts compared with control hearts had better percent recovery of maximum left ventricular (LV) developed pressure (83.9 +/- 2.2% versus 73.6 +/- 3.0%, mean +/- SEM), LV dP/dt (78.4 +/- 3.3% versus 67.4 +/- 3.4%), coronary blood flow (159.5 +/- 12.2% versus 84.4 +/- 3.5%), and myocardial oxygen consumption (129.8 +/- 16.5% versus 71.2 +/- 6.2%) (all p < 0.05). In each heart, we also tested coronary vascular resistance (CVR) response to 10(-6) mol/l acetylcholine (ACh) infusion to assess endothelial function. Percent recovery of CVR response to ACh was higher in antibody-treated hearts (38.4 +/- 4.3%) than control hearts (13.4 +/- 12.8%) (p = 0.08). CONCLUSIONS: These results suggest that leukocyte adherence to endothelium mediated by CD18 plays an important role in reperfusion after hypothermic ischemia. Antibody to CD18 may be useful in myocardial and endothelial protection during surgically induced ischemia.

Animals↗

Coronary endothelial injury by cold crystalloid cardioplegic solution in neonatal lambs.

BACKGROUND: Hypothermic cardioplegia generally improves the recovery of the mechanical function of the heart after ischemia, but some components of cold cardioplegia may produce endothelial injury that can offset the protective effects of cardioplegia. This study was undertaken to evaluate the effect of extremely hypothermic cardioplegia on the recovery of coronary endothelial and cardiac mechanical function after ischemia in the immature heart. METHODS AND RESULTS: Three groups of eight isolated, blood-perfused, neonatal lamb hearts each had myocardial temperature maintained at 10 degrees C during 2 hours of global ischemia but received hourly doses of crystalloid cardioplegic solution at temperatures of 10 degrees C (group A), 4 degrees C (group B), and 2 degrees C (group C). The percent recovery of isovolumic left ventricular maximum developed pressure in groups A (86.6 +/- 7.7) and B (90.5 +/- 7.5) was higher than in group C (78.6 +/- 6.3), and maximum dP/dt in groups A (89.6 +/- 8.6) and B (89.5 +/- 5.7) was higher than in group C (79.4 +/- 9.0) at 30 minutes of reperfusion (p < 0.05). Groups A (136.8 +/- 20.9) and B (142.8 +/- 27.7) achieved higher recovery of coronary blood flow (as percentage of baseline) at 15-minute reperfusion than group C (108.5 +/- 26.2), and myocardial oxygen consumption was higher in groups A (68.3 +/- 14.6, 92.1 +/- 21.1) and B (68.8 +/- 19.9, 85.3 +/- 25.5) than in group C (46.3 +/- 14.7, 57.2 +/- 14.2) at 15 and 30 minutes of reperfusion, respectively (p < 0.05). Percent recovery of the coronary vascular resistance responses to 10(-7) M concentration of an endothelium-dependent vasodilator (acetylcholine) in groups A (71.9 +/- 9.0) and B (66.2 +/- 23.1) was higher than in group C (24.2 +/- 14.3) (p < 0.05), whereas responses to 3 x 10(-5) M concentration of endothelium-independent vasodilator (nitroglycerin) were the same. CONCLUSIONS: Excessively cold cardioplegic solution may cause endothelial dysfunction (reduced acetylcholine response) and reduced recovery of mechanical function in the neonatal heart.

Acetylcholine↗

A spigelian hernia in an infant.

The case of a two-month old Japanese girl with a left side Spigelian hernia that developed during the course of recovery from the surgical treatment of a meningomyelocele and ventriculo-peritoneal shunting (V-P shunting) is reported on. At this time, to our knowledge, 20 cases involving infants and children have been reported on in world-wide medical literature. Of these cases, 4 cases were caused by trauma, 1 by abdominal surgery, and the others had no evident causes. Our patient had a meningomyelocele, and underwent a V-P shunting. However, a cause and effect relationship between the Spigelian hernia and the treatment of the meningomyelocele followed by V-P shunting is inconceivable. We doubt any relationship between the preceding neurosurgery and the development of the hernia. This is the first case of infantile Spigelian hernia reported on in Japan.

Female↗

Evidence for the role of neutrophils in reperfusion injury after cold cardioplegic ischemia in neonatal lambs.

The role of neutrophils in reperfusion injury after hypothermic, cardioplegia-protected ischemia is incompletely understood but may involve neutrophil-endothelial interactions. We examined 33 isolated blood-perfused neonatal lamb hearts arrested for 2 hours with 15 degrees C potassium cardioplegic solution and reperfused with unmodified blood (group C, n = 9), with neutrophil-depleted (Sepacell filter) blood (group ND, n = 9), with the addition of CV-3988, a platelet-activating factor antagonist, to the perfusate (group NA, n = 9), and with neutrophil-depleted blood plus CV-3988 (group ND/NA, n = 6). The percent recovery of isovolumic left ventricular developed pressure at a fixed balloon volume at 30 minutes after reperfusion in groups ND (84.8% +/- 11.8%, mean +/- standard deviation), NA (89.9% +/- 11.5%), and ND/NA (87.8% +/- 6.4%) were higher than in group C (73.1% +/- 7.9%) (p less than 0.05). Groups NA (105.5% +/- 13.7%) and ND/NA (108.0% +/- 11.2%) achieved higher percent recovery of coronary blood flow than group C (84.4% +/- 10.4%) (p less than 0.05). In each heart, we also tested coronary vascular resistance response to infusion of acetylcholine 10(-6) mol/L to assess endothelial function. Percent recovery of coronary vascular resistance response to acetylcholine was higher in groups ND (56.8% +/- 31.4%), NA (56.3% +/- 17.3%), and ND/NA (58.7% +/- 24.8%) than in group C (13.3% +/- 38.3%) (p less than 0.05). These results show that, after ischemia/reperfusion, groups ND, NA, and ND/NA had better recovery of both mechanical and endothelial function than group C. The parallel changes in recovery of mechanical and endothelial function suggest that neutrophil-endothelial interactions may be a significant factor in reperfusion injury.

Acetylcholine↗

Growth of composite conduits utilizing longitudinal arterial autograft in growing lambs.

We examined the growth potential of a longitudinal strip of autologous aortic wall incorporated in an autologous pericardial conduit in 10 lambs (mean age 26 days, mean weight 10.1 kg). A 15 mm length of descending thoracic aorta (diameter 11.5 +/- 7 mm) was excised and replaced with a composite autograft conduit of autologous pericardium with a longitudinally inserted aortic strip 5 mm in width taken from the excised aortic tissue. Radiopaque markers along all suture lines allowed determination of growth of the aortic strip relative to growth of the composite conduit and descending aorta, in addition to growth assessment by pathologic analysis. Plain x-ray films and aortograms were performed at 7 days (baseline) and at 3, 6, 9, and 12 months. No graft became stenotic or aneurysmal. The diameter of the descending aorta distal to the conduit increased from 11.7 +/- 1.3 mm to 18.7 +/- 2.1 mm. Appropriate growth of the autograft conduit was demonstrated by a minimal change in the diameter ratio of conduit to distal aorta from 1.00 to 1.02 during a period of 12 months. The aortic strip increased to 172% +/- 19%, 148% +/- 15%, and 256% +/- 31% of baseline width, length, and area, respectively (p less than 0.05). Histologic study confirmed the maintenance of normal architecture in the aortic strip and colonization of the pericardial tissue by aortic intimal and medial elements. A clinical implant with an autologous aortic strip in an aortic homograft in a 4-year-old child with tetralogy and pulmonary atresia has also grown, according to angiography, from 15 to 21 mm in diameter at 1 year's follow-up. This study confirms that the incorporation of a free autologous arterial patch graft as part of cardiovascular reconstructive procedures permits growth.

Animals↗

Analysis of clinical factors for survival after left and biventricular bypass using centrifugal pump following open heart surgery in infants and adults.

A total of eight patients, including three infants, received left or biventricular assist using centrifugal pump (CFP) following open heart surgery. Three infants, aged 9-11 months and with complex cardiac lesions, were supported by left heart bypass (LHB) using pediatric type CFP for 63 h, 64 h, and 13 days. All were weaned from LHB, but long-term survival was not obtained, mainly due to complications. In five adult patients, LHB alone was used in three, and biventricular support in two for 33-240 h with three survivals. The factors related to unsuccessful recovery were delayed start of support and multiorgan failure.

Adult↗

Hand-made valved conduit with high-porosity knitted graft and glutaraldehyde-treated autologous pericardial trileaflet valve.

In 10 patients with various congenital heart defects requiring reconstruction of right ventricle to pulmonary artery continuity, a new hand-made valved conduit was introduced. To avoid late stenosis with peel formation of the graft, high-porosity Golaski knitted graft was chosen. The graft was sealed by fibrin glue, and autologous pericardium was treated with glutaraldehyde and used to construct a trileaflet valve inside the graft. This hand-made graft was pliable with good conformability. The valve function was found good in the intermediate follow-up in 8 patients. This composite valved conduit may be a good alternative to the xenograft valved conduit when allograft conduit is not available.

Bioprosthesis↗