Europium adsorption on multiwall carbon nanotube/iron oxide magnetic composite in the presence of polyacrylic acid.

This paper examines the interaction between Eu(III) and a multiwall carbon nanotube (MWCNT)/iron oxide magnetic composite in the absence and presence of poly(acrylic acid) (PAA). PAA was used as a surrogate for natural organic matter. The effects of pH, initial Eu(III) concentration, and PAA on Eu(III) adsorption on the magnetic composite were investigated using a batch technique. Percentage adsorption of Eu(III) on the magnetic composite increased with increasing pH and decreased with initial Eu(III) concentration. PAA adsorption on the magnetic composite decreased with increasing pH and was not obviously affected bythe presence of Eu(III). The presence of PAA resulted in strong enhancement of Eu(III) adsorption below pH 4.5. However, above pH 5, an increase in soluble Eu-PAA complexes resulted in a decrease in Eu(III) adsorption on the magnetic composite. With increasing PAA concentrations, maximum adsorption of Eu(III) decreased and the adsorption "edge" shifted toward a lower pH range. Obvious difference of Eu(III)/PAA addition sequences on Eu(III) adsorption was observed above pH 4. The Freundlich model fitted Eu(III) adsorption isotherms very well in the absence and presence of PAA. These results are important for estimating and optimizing the removal of organic and inorganic pollutants by the magnetic composite.

[Successful staged repair of a symptomatic neonate of tetralogy of Fallot with severe absent pulmonary valve syndrome].

Tetralogy of Fallot with absent pulmonary valve has been classified to a few groups. The most severe one is characterized by symptomatic onset immediately after birth. The others are no or slightly symptomatic at least during their neonatal period. In a severely symptomatic 12-day-old neonate of tetralogy of Fallot with absent pulmonary valve who had required intubation immediately after birth, tight pulmonary banding and left side modified Blalock-Taussig shunt were performed on emergency basis. Consequently, prior massive pulmonary regurgitation was decreased significantly. Forty-five days after this first stage operation, he weaned from respiratory management. At 1-year-old, radical repair based on conotruncal repair, which consisted of patch closure of ventricular septal defect preserving the tricuspid septal leaflet function, resection of anterior wall of enlarged left pulmonary artery, and right ventricular outflow tract reconstruction using autologous tissue and a pericardial patch was performed. Bicuspid pulmonary valve, posterior one of procured autologous pulmonary wall and anterior one of polytetrafluoroethylene (PTFE) respectively, was created to minimize deterioration of the pulmonary insufficiency. Although postoperative cardiac function was kept feasible showing his central venous pressure of 7 mmHg in the main, postoperative general course was eventful especially regarding the respiratory function. The patient was weaned from the prolonged ventilator management 5 months after this radical repair eventually. Generally, to diminish the massive pulmonary regurgitation in early lifetime period could reduce a progressive airway obstruction and minimize pulmonary tissue damage. However, even after the total correction in this case, considerable peripheral segmental pulmonary obstructive lesions were persistent according to the perfusion lung scanning with 99mTc macroaggregated albumin and 99mTechnegas ventilation lung scanning studies. This persistent, supposed to be innate, pulmonary obstructive lesions might prevent ordinal recovery after cardiac radical repair for this most severe subtype of absent pulmonary valve syndrome.

Common iliac artery aneurysm due to fibromuscular dysplasia in infants.

A seven-month old female with a huge aneurysm of the right common iliac artery and multiple stenoses of her bilateral renal arteries is described. At surgery, a Gore-Tex graft was interposed between the proximal common iliac artery and the external iliac artery. A histological examination of the aneurysmal wall was compatible with medial fibromuscular dysplasia (FMD). After surgery, her blood pressure was controlled in the normal range on medical treatment. This case would be the first case of a huge common iliac artery aneurysm due to FMD in infants.

Changes in 99mTechnegas ventilation lung scan in a newborn with absent pulmonary valve syndrome.

A newborn infant with tetralogy of Fallot and absent pulmonary valve was successfully corrected in two stages. Absent pulmonary valve syndrome presenting in early infancy manifests severe respiratory symptoms that still make challenging both management and surgical treatment. This is ascribed to tracheobronchial compression by the extremely dilated pulmonary arteries, and to the resultant pulmonary obstructive lesions. We report herein the first findings of 99mTechnegas ventilation lung scanning in an infant with the syndrome to assess the pulmonary obstructive lesions.

Bradycardia and the role of beta-blockade in the amelioration of left ventricular dysfunction.

BACKGROUND: It is clear that beta-blockers are effective for treatment of congestive heart failure, but their mechanism of action remains controversial. Hypothesized mechanisms include normalization of beta-receptor function and myocardial protection from the effects of catecholamines, possibly by the institution of bradycardia. We hypothesized that beta-blockade-induced bradycardia was an important mechanism by which these agents were effective for correction of LV dysfunction. METHODS AND RESULTS: In 2 groups of dogs with mitral regurgitation and LV dysfunction, beta-blockers were instituted. In 1 group that received beta-blockers and pacing (group beta+P), a pacemaker prevented the natural bradycardia that beta-blockers cause. In both groups, substantial LV dysfunction developed. Before beta-blockade, the end-systolic stiffness constant decreased from 3. 5+/-0.1 to 2.7+/-0.2 (P<0.01) at 3 months in group beta+P. A similar reduction occurred in the group that eventually received only beta-blockers (group betaB). In group betaB, end-systolic stiffness improved after 3 months of beta-blockade from 2.9+/-0.2 to 3.5+/-0.4 and was not different from baseline. However, in group beta+P, end-systolic stiffness failed to improve (2.7+/-0.2) after 3 months of mitral regurgitation, and was 2.9+/-0.2 at the end of the studies. The contractile function of cardiocytes isolated from the ventricles at the end of the studies confirmed these in vivo estimates of contractility. CONCLUSIONS: We conclude that institution of bradycardia is a major mechanism by which beta-blockers are effective for restoration of contractile function in a model of LV dysfunction.

Interruption of the aortic arch at the isthmus with DiGeorge syndrome and 22q11.2 deletion.

A 6-day-old male with interruption of the aortic arch at the isthmus (type A) had the typical phenotype of DiGeorge syndrome. There was also a doubly committed juxta-arterial ventricular septal defect and an unobstructed left ventricular outflow tract. Hypoplasia of the thymus was confirmed during a modified Blalock-Park operation. He had persistent hypocalcemia, and was susceptible to infection. He was subsequently revealed by the use of fluorescence in situ hybridization analysis to have 22q11.2 deletion. Interruption of the aortic arch at the isthmus is presumed to reflect abnormal fetal hemodynamics, and is considered a distinct pathogenetic entity from interruption between the left common carotid and subclavian arteries, the latter being the variant more frequently associated with DiGeorge syndrome. In our case, the 22q11.2 deletion likely played a major role in the etiology of the interrupted aortic arch.

[Emergency CABG for patients with LMT lesion treated by mechanical cardiac support].

We retrospectively analysed the perioperative course of 22 patients who underwent emergency CABG for severe left main trunk lesion. The causes of LMT lesion were spontaneous acute myocardial infarction in 14 patients and failed coronary intervention and coronary angiography in 8 patients. IABP was used preoperatively in all patients and additional coronary perfusion catheter were induced for two patients and PCPS was for one patient. Overall incidence in-hospital operative mortality was 22.7% (5/22), four of them were due to cardiac related causes and one of them was due to acute renal failure. Postoperative level of max CPK enzyme was significantly higher in death cases compared to survivors, 6,330 +/- 3,649 versus 1,299 +/- 1,417 IU/dl. We considered that the most important factors in surgical strategy for acute coronary syndrome with LMT lesion were as follows: improvement of hemodynamics with mechanical cardiac support by IABP or/and PCPS, protection of broad myocardial ischemia using coronary perfusion catheter and urgent surgical revascularization by emergency CABG.

[A survey of opioid use in preanesthetic medication].

A mailing survey was carried out to assess the current practice of sedative premedication in anesthesia. Questionnaires were sent by mail to 77 university hospitals. We especially evaluated use of opioids for premedication. Sixty-one percent (n = 47) of the hospitals answered these questionnaires and 31 percent (n = 15) of them were using opioids for the preanesthetic medication. Pethidine was used most frequently for premedication of all opioids, and morphine was often used for the premedication before cardiac surgery. All opioids were administrated intramusculary both in adults and children.

[Surgical relief of airway obstruction from a double aortic arch associated with corrected transposition of the great arteries, pulmonary atresia and bilateral patent ductus arteriosus in a neonate].

A rare 20-day-old male with double aortic arch, corrected transposition of the great arteries (cTGA), pulmonary atresia and bilateral patent ductus arteriosus (PDA) was transported to our institute because of severe respiratory dysfunction and cyanosis. The patient had been already intubated and ventilated on respirator. A echocardiography and cine-angiography demonstrated that the both sides aortic arch had almost identical sizes, originating common carotid arteries and subclavian arteries and PDAs respectively, and the descending aorta located on the left side of the mid-line. At the first surgery, the distal of the right aortic arch was divided just proximal to the descending aorta after complete tissue dissection around the arch. The divided right sided aortic arch was mobilized from posterior to anterior aspect of the bronchus. Then the right subclavian artery was divided and an original Blalock-Taussig shunt was employed. The right sided PDA was ligated. After the first surgery, respiratory dysfunction lasted for weeks mainly because of the PGE1 dependent left sided PDA. At the second surgery, left sided modified Blalock-Taussig shunt was constructed and the left sided PDA was divided. These procedures resulted in stable respiratory status and oxygen saturation. The patient was extubated three days later and now in satisfactory clinical condition.

Premorbid determinants of left ventricular dysfunction in a novel model of gradually induced pressure overload in the adult canine.

BACKGROUND: When a pressure overload is placed on the left ventricle, some patients develop relatively modest hypertrophy whereas others develop extensive hypertrophy. Likewise, the occurrence of contractile dysfunction also is variable. The cause of this heterogeneity is not well understood. METHODS AND RESULTS: We recently developed a model of gradual proximal aortic constriction in the adult canine that mimicked the heterogeneity of the hypertrophic response seen in humans. We hypothesized that differences in outcome were related to differences present before banding. Fifteen animals were studied initially. Ten developed left ventricular dysfunction (dys group). Five dogs maintained normal function (nl group). At baseline, the nl group had a lower mean systolic wall stress (96 +/- 9 kdyne/cm2; dys group, 156 +/- 7 kdyne/cm2; P < .0002) and greater relative left ventricular mass (left ventricular weight [g]/body wt [kg], 5.1 +/- 0.36; dys group, 3.9 +/- 0.26; P < .02). On the basis of differences in mean systolic wall stress at baseline, we predicted outcome in the next 28 dogs by using a cutoff of 115 kdyne/cm2. Eighteen of 20 dogs with baseline mean systolic stress > 115 kdyne/cm2 developed dysfunction whereas 6 of 8 dogs with resting stress < or = 115 kdyne/cm2 maintained normal function. CONCLUSIONS: We conclude that this canine model mimicked the heterogeneous hypertrophic response seen in humans. In the group that eventually developed dysfunction there was less cardiac mass despite 60% higher wall stress at baseline, suggesting a different set point for regulating myocardial growth in the two groups.

[A case of modified Fontan operation with reconstruction of the nonconfluent pulmonary artery].

A three-year-old girl with complex cardiac anomalies and right isomerism successfully underwent a modified Fontan procedure and reconstruction of the nonconfluent pulmonary artery using autologous tissues. These cardiac anomalies included single right ventricle, atresia of the pulmonary trunk with nonconfluent pulmonary artery, atrial septal defect, common atrioventricular valve, bilateral PDAs, and bilateral SVCs. Preoperative cardiac catheterization showed elevated pulmonary artery pressure (mean pressure of 24 mmHg) and a small orifice of common pulmonary vein chamber. Pulmonary arteriographies showed balanced development of the branches. Indication for Fontan procedure was finally determined by measurement of the pulmonary artery and vein pressures and pulmonary vascular resistance before the cardiopulmonary bypass in the operation. Nonconfluent pulmonary artery was reconstructed by direct anastomosis of the right and left branches in the posterior aspect and enlarged with autologous pericardium patch. Intracardiac anomalies were repaired by enlargement of common pulmonary vein orifice (from 5 mm to 15 mm in diameter) and right atrial oblique partition. Furthermore, Fontan circulation was established by pulmonary artery angioplasty, direct anastomosis of left SVC to left pulmonary artery and direct anastomosis of right atrial appendage to pulmonary artery. Postoperative clinical course was uneventful, and cardiac catheterization showed mean right atrial pressure of 14 mmHg, cardiac index of 3.5 l/min/m2, and no pressure gradient at the site of reconstruction of the pulmonary artery.

Origin of the left coronary artery from the right pulmonary artery.

We report the successful surgical treatment of a 12-year-old boy with a rare type of Bland-White-Garland syndrome with mitral regurgitation, in which an anomalous left coronary artery arose from the middle portion of the right pulmonary artery, employing the direct translocation of the left coronary artery and mitral valvuloplasty.

[A case of one stage-repair of interrupted aortic arch and ventricular septal defect in neonate using a separated cardiopulmonary bypass].

We report a case of one stage-repair of interrupted aortic arch and ventricular septal defect in neonate. The operation was performed at the age of 14 days. After a median sternotomy incision, a separated cardiopulmonary bypass was commenced through the ductus and a 4 mm EPTFE graft which was anastomoted to the right subclavian artery. Cerebral circulation was maintained through the graft during reconstruction of the aortic arch. Our method is useful regarding that brain damage can be avoided which may be induced by total circulatory arrest.

[Anomalous origin of the right pulmonary artery from the ascending aorta: a case report].

We report a successful case of anomalous origin of the right pulmonary artery from the ascending aorta. A 34 days old infant, who had suffered from cardiogenic shock, underwent a direct anastomosis of the right pulmonary artery to the main pulmonary artery behind the ascending aorta under cardiopulmonary bypass. Postoperative catheterization showed no significant stenosis over the anastomosis and normalized pulmonary artery pressure. We conclude that early surgical correction is necessary in the treatment of this life threatening disease.

Can concordant criss-cross heart be ameliorated by hemodynamic changes?

A 2-year-old female child with "ameliorated" concordant criss-cross heart, complicated superior-inferior ventricles, complete transposition of great arteries, hypoplastic right ventricle, ventricular septal defect, and aortic coarctation is described. The patient underwent subclavian flap, pulmonary artery banding, and balloon atrioseptostomy at age 1 month. The ameliorated concordant criss-cross anatomy was obtained after 2 years of follow-up. This dynamic morphologic change allowed us to perform a subsequent anatomic correction.

[Initial ultrafiltration to the priming solution with preserved blood for cardiopulmonary bypass in infants].

In case of open heart surgery in infants, the initial priming solutions (IPS) of the cardiopulmonary bypasses (CPB) include considerable amount of preserved blood to assure us of the proper hematocrit during the CPB. Aiming at elimination of unfavorable effects of preserved blood on hearts and vessels, the ultrafiltrations (UF) to the IPS before the beginnings of CPB had been carried out in 42 pediatric cases. The IPS amounted to 915 +/- 25 (mean +/- SE) ml. in which 581 +/- 31 ml of preserved blood were included. The 1.5-fold amount infusions over the IPS, consisted of 5% glucose, normal saline and fresh frozen plasma, were added to the IPS, and just the same amount fluid were removed out by the UF. The concentrations of potassium, NH3, lactic acid and pyruvic acid in the IPS decreased significantly after UF (p = 0.001). The potassium concentrations were compared among the blood of patients (PB), the IPS before UF (IPS1), the IPS after UF (IPS2), and the mixed blood drawn 5-10 minutes after the beginnings of CPB (MB) in the cases under the age of 1 year (group-I, n = 26, 4.7 +/- 0.3 kg) and in the elders (group-E, n = 16, 15 +/- 2 kg). The results showed all significant differences but "IPS2 and MB" in group-I, and but "PB and MB" in group-E (ANOVA p = 0.001, p < 0.01 by Newman-Keuls). The 98% of cases kept their innate heart beatings until the aortic clamps at 22 +/- 1 degrees C (sending blood temp.).(ABSTRACT TRUNCATED AT 250 WORDS)

[Two cases of gross E-type tracheo-esophageal fistulae associated with interruption of the aortic arch and coarctation of the aorta in early infancy].

Two cases of Gross E-type tracheoesophageal fistulae associated with interruption of the aortic arch in one and coarctation of the aorta in the other in early infancy were treated radically at Nagano Children's Hospital during the preceding 4 months until January 1994. The tracheoesophageal fistulae were noticed after the first stage surgery for the aortic arch anomalies, because of the remarkable abdominal distension under the intubated and ventilated condition of general anesthesia. Both the bronchial and esophageal optical fiber examinations were performed which proved useful to detect the fistulae. In each case, the transcervical division of the fistula was performed on an emergency basis. The external diameter of the fistula was 4 and 5 mm respectively. The fistulae dilated synchronously with ventilation. The early detection and surgical correction of the tracheoesophageal fistula can prevent serious complications such as DIC as seen in the first case probably caused by respiratory infection associated with the prolonged mechanical ventilation. Successful intracardiac repair were performed in both cases on the 25th and 7th day following the correction of the fistulae respectively.

Acute changes in myosin heavy chain synthesis rate in pressure versus volume overload.

The left ventricular hypertrophy that develops with the volume overload of mitral regurgitation is relatively less than that which develops with the pressure overload of aortic stenosis even when both lesions are severe. The hypertrophy that develops must be the sum of changes in the rate of myocardial protein synthesis and degradation. In the present canine study, we explored early changes in the synthesis rate of myosin heavy chain in response to severe acute pressure overload versus that of the severe acute volume overload of mitral regurgitation. We tested the hypothesis that in acute overload, the rate of protein synthesis would increase less in the volume-overload model than in the pressure-overload model, a potential partial mechanism for the discrepancy in the eventual total amount of hypertrophy that develops in these two lesions. Acute pressure overload was produced by inflating a balloon in the descending aorta, and acute volume overload was produced by using our closed-chest mitral chordal rupture technique. In both models, the hemodynamic lesion that was created was severe. In eight dogs with pressure overload, the average gradient across the balloon was 119.8 +/- 6.1 mm Hg. In six dogs with volume overload, the average regurgitant fraction was 0.67 +/- 0.06. Six other dogs served as controls. The average rate of myosin heavy chain synthesis in control dogs was 2.7 +/- 0.2% per day, virtually identical to the rate we found in the severe volume-overload model. In contrast, the rate was increased in the pressure-overload model by 30% to 3.5 +/- 0.3% per day (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Role of microtubules in contractile dysfunction of hypertrophied cardiocytes.

Cardiac hypertrophy in response to systolic pressure overloading frequently results in contractile dysfunction, the cause for which has been unknown. Since, in contrast, the same degree and duration of hypertrophy in response to systolic volume overloading does not result in contractile dysfunction, we postulated that the contractile dysfunction of pressure hypertrophied myocardium might result from a direct effect of stress as opposed to strain loading on an intracellular structure of the hypertrophied cardiocyte. The specific hypothesis tested here is that the microtubule component of the cytoskeleton is such an intracellular structure, which, forming in excess, impedes sarcomere motion. The feline right ventricle was either pressure overloaded by pulmonary artery banding or volume overloaded by atrial septotomy. The quantity of microtubules was estimated from immunoblots and immunofluorescent micrographs, and their mechanical effects were assessed by measuring sarcomere motion during microtubule depolymerization. We show here that stress loading increases the microtubule component of the cardiac muscle cell cytoskeleton; this apparently is responsible for the entirety of the cellular contractile dysfunction seen in our model of pressure-hypertrophied myocardium. No such effects were seen in right ventricular cardiocytes from normal or volume-overloaded cats or in left ventricular cardiocytes from any group of cats. Importantly, the linked microtubule and contractile abnormalities are persistent and thus may be found to have significance for the deterioration of initially compensatory cardiac hypertrophy into the congestive heart failure state.