Gallium Phosphide photoanode coated with TiO2 and CoOx for stable photoelectrochemical water oxidation.

Gallium Phosphide (GaP) has a band gap of 2.26 eV and a valance band edge that is more negative than the water oxidation level. Hence, it may be a promising material for photoelectrochemical water splitting. However, one thing GaP has in common with other III-V semiconductors is that it corrodes in photoelectrochemical reactions. Cobalt oxide (CoOx) is a chemically stable and highly active oxygen evolution reaction co-catalyst. In this study, we protected a GaP photoanode by using a 20 nm TiO2 as a protection layer and a 2 nm cobalt oxide co-catalyst layer, which were both deposited via atomic layer deposition (ALD). A GaP photoanode that was modified by CoOx exhibited much higher photocurrent, potential, and photon-to-current efficiency than a bare GaP photoanode under AM1.5G illumination. A photoanode that was coated with both TiO2 and CoOx layers was stable for over 24 h during constant reaction in 1 M NaOH (pH 13.7) solution under one sun illumination.

Intraventricular repair of double-outlet right ventricle with noncommitted ventricular septal defect: advantages of multiple patches.

OBJECTIVE: The objective of this paper is to report our experience with biventricular repair of double-outlet right ventricle with noncommitted ventricular septal defect by means of multiple patches that simplify and render feasible the intraventricular correction of this complex anomaly. METHODS: From April 1987 to April 1999, in 18 patients with double-outlet right ventricle and noncommitted ventricular septal defect, a technical modification that used multiple patches of bovine pericardium was used to construct an intraventricular tunnel connecting the left ventricle to the aorta. Ages ranged from 2 months to 13 years (mean age 4.73 +/- 3.41 years). RESULTS: The early mortality was of 11.1% (2 patients). Surviving patients were followed up for a mean of 2.65 years. Three late deaths (16.6%) occurred: 5 months, 7 months, and 7 months after the operation. All but 1 patient are in New York Heart Association class I. CONCLUSION: The use of multiple patches for biventricular correction of this anomaly simplifies and renders feasible the intraventricular repair in cases in which the 1-patch technique was deemed impossible.

Surgical treatment of Ebstein's anomaly. Early and late results in twenty patients subjected to valve replacement.

Twenty patients with Ebstein's anomaly underwent corrective operations between 1965 and 1978. Sixteen were in Functional Class III or IV (N.Y.H.A.) and four were in Class II but were having episodes of anoxia, syncope, or a rapid increase in cardiac size. In the first 10 cases (1965 to 1972) the tricuspid valve was replaced with a Starr-Edwards prosthesis, and in the second group (1972 to 1978) a dura mater valve was used. Five patients also underwent plication of a very large atrialized right ventricular segment. The atrial septal defect was closed totally in four cases, partially in eleven cases, and left open in five cases; one patient also underwent closure of the ventricular septal defect. Four patients died in the immediate postoperative period, three of whom were in the first group. There were three late postoperative deaths in the remaining 16 patients, all of them in the first group. All 13 of the surviving patients are in Functional Class I, except for one patient who is in Class II.

Effect of intentional hemodilution on platelet survival in secondary pulmonary hypertension.

Platelet regeneration time was assessed in 13 young adults with pulmonary hypertension and polycythemia secondary to congenital heart defects who underwent isovolemic hemodilution to improve clinical status and coagulation defects. The estimated platelet half-life in patients with Eisenmenger's complex was significantly shortened in comparison with normal subjects (3.8 +/- 1.9 vs 4.8 +/- 1.0 days, p less than 0.05). Hemodilution was carried out with no adverse effects, using low molecular weight dextran solutions. Lowering hematocrit from 61 to 50 percent resulted in a significant increase in platelet half-life from 3.8 +/- 1.9 to 5.7 +/- 1.8 days (p less than 0.02), which was followed by a marked rise in platelet count from 149 +/- 31 to 209 +/- 47 x 10(9) platelets/L (p less than 0.003). Arterial oxygen tension did not change significantly. These observations indicate that high hematocrit levels may have accounted for the shortened platelet survival and thrombocytopenia in these patients. Significant hemodilution may lead to a marked improvement in platelet abnormalities in patients with Eisenmenger's complex.

Congenital tricuspid stenosis treated by a palliative open operation. Report of a case.

The case is presented of a patient with congenital tricuspid stenosis who was treated successfully by a palliative open operation. The preoperative diagnosis was tricuspid atresia. At operation, however, congenital tricuspid stenosis was detected and managed by commissurotomy.. The postoperative course was very good. Later, the associated ventricular septal defect (VSD), pulmonary annular stenosis, and probably the atrial septal defect (ASD) will be corrected. We emphasize the importance of diagnosing congenital tricuspid stenosis correctly, because of the possibility of operating upon the valve itself.

Abnormal multimeric and oligomeric composition is associated with enhanced endothelial expression of von Willebrand factor in pulmonary hypertension.

Abnormalities in endothelial von Willebrand factor (vWF) structure have been reported in pulmonary hypertension. These include loss of high molecular weight plasma multimers, resulting in decreased biologic activity. If endothelial processing of vWF is altered in this disorder, abnormalities in oligomeric composition may also be expected. We examined this possibility in ten adult patients with primary pulmonary hypertension. Enhanced endothelial vWF expression in these patients was indicated by increased plasma levels of vWF antigen (vWF:Ag) (214 +/- 91 vs 99 +/- 51 percent activity in controls, p < 0.001) and intense immunoperoxidase stain of pulmonary arterial endothelium for vWF (autopsy, 1 patient). Plasma from these patients also had a decreased capacity of inducing platelet aggregation in the presence of ristocetin, relative to vWF:Ag levels (57 +/- 20 percent activity). In addition to mild loss of the largest multimers, changes in oligomeric composition of plasma vWF were observed in most patients using both agarose and polyacrylamide gel electrophoresis. These included decreased concentration of dimeric (470 kDa) vWF in most patients, variable concentration of the 860-kDa fraction, and a relative decrease in subunit (223 kDa) density in subjects with elevated vWF:Ag. These findings provide additional information on the mechanisms responsible for endothelial production of dysfunctional vWF in patients with pulmonary hypertension.

Lung beta-adrenoceptors in pulmonary hypertension. A study of biopsy specimens in children with congenital heart disease.

Characteristics of beta-adrenoceptors were analyzed using radioligand-binding techniques with 3H-dihydroalprenolol in lung specimens from 11 children with pulmonary hypertension (median age, three years) undergoing surgical repair of congenital heart defects and four pediatric control subjects (median age, five years) undergoing thoracotomy for removal of neoplasms or cysts. Scatchard analysis of 3H-DHA binding to lung membranes showed similar values of the dissociation constant in both groups (Kd = 0.72 +/- 0.22 nM in patients vs 1.22 +/- 0.22 nM in controls; p = NS). The receptor density was significantly increased in patients in comparison with controls, with respective values of 164 +/- 19 and 95 +/- 13 fmol/mg of protein (p less than 0.025), and correlated directly with mean pulmonary arterial pressure (r = 0.82; p less than 0.0005). No significant relationship was observed between receptor number and pulmonary arterial medial thickness. Thus, the increase in receptor density in these patients may be related to adaptative changes in cells other than vascular smooth muscle.

Epidemiologic investigation of an outbreak of coagulase-negative Staphylococcus primary bacteremia in a newborn intensive care unit.

Infections due to coagulase-negative Staphylococcus (CNS) are an ever-increasing nosocomial problem, particularly in the pediatric population. The authors describe a cluster of three primary bloodstream infections due to CNS in a newborn intensive care unit that occurred between November 23 and December 2, 1992. Two children died as a direct consequence of the bacteremia; at autopsy, one had a large bacteria-containing thrombus extending from the insertion site of a central catheter to the superior vena cava. The children were placed in isolation, and the nursing and medical staff were given topical nasal mupirocin. Plasmid analysis performed later disclosed three different blood isolates that also were different from any of the staff's nasal isolates. The authors concluded that molecular methods such as plasmid analysis are important tools in identifying true outbreaks and can prevent needless interventions, such as those during this cluster.

Adventitial layer enlargement correlates with the percentage of medial thickness in peripheral pulmonary arteries from patients with congenital heart defects.

Arterial walls undergo modifications during the course of pulmonary hypertension, particularly in the medial and intimal layers, leading to progressive occlusion of the lumen. Adventitial layer enlargement has been described as being present in the experimental hypoxic model and in the persistent pulmonary hypertension of the newborn. It was suggested that this enlargement may be related to stimulating factors derived from the medial smooth muscle cells. This study was designed to verify if different degrees of medial hypertrophy are correlated to the volume density of the adventitial layer in pulmonary hypertension secondary to congenital heart defects. Reviewing 21 lung biopsies from patients with congenital heart defects, we concluded that there is a statistically significant positive linear correlation between the mean percentage of medial arterial thickness and the volume density of the adventitial layer in the biopsies showing isolated medial hypertrophy. On the other hand, in biopsies showing frequent intimal proliferative lesions and irregular medial layer hypertrophy the correlation coefficient was lower. These findings suggest that the adventitial layer participates in the arterial remodeling process in secondary pulmonary hypertension, and that its enlargement depends on the qualitative degree of pulmonary vaso-occlusive disease.

Ebstein's malformation of the tricuspid and mitral valves associated with hypoplasia of the ascending aorta.

The clinical and morphological features of Ebstein's malformation were well defined many years ago. This report analyses the clinical and morphological aspects of an unusual case which presented Ebstein's malformation of both the tricuspid and mitral valves in association with hypoplasia of the ascending aorta.

Coexistence of divided left atrium (cor triatriatum) and tetralogy of Fallot.

The association of a partitioned left atrium (cor triatriatum) and tetralogy of Fallot has been reported a few times in the literature. In all of these cases, there was no clinical evidence of an obstructive lesion in the left heart, raising difficulties in establishing the proper diagnosis. We call attention to this rare combination of anomalies and to the particular morphological presentation of the dividing atrial shelf, which was partially formed by the wall of the left superior caval vein.

Aggregation of platelets in whole blood from children with pulmonary hypertension.

The response of aggregation of platelets to adenosine diphosphate (7.5-120 microM) and collagen (1.25 micrograms/ml) was assessed in whole blood (impedance method) in 10 children with pulmonary hypertension (hematocrit range, 42 to 71%). The response to collagen was normal (9.08 +/- 3.47 vs. 10.36 +/- 1.86 ohms in controls, P = NS) while there was a decreased response to adenosine diphosphate (6.98 +/- 3.83 vs. 11.21 +/- 2.02 ohms, P less than 0.01), in spite of high concentrations of the inducer. Lowering the hematocrit in vitro to 40% with autologous platelet-rich plasma resulted in a rise in the platelet count from 171 +/- 63 to 225 +/- 84 x 10(9) platelets/1 (P less than 0.001) and a significant increase in the response to adenosine diphosphate from 6.98 +/- 3.83 to 9.89 +/- 3.66 ohms (P less than 0.02). As in the baseline condition, high concentrations of adenosine diphosphate were required. The response to collagen did not change significantly. The results indicate that aggregatory response of platelets is relatively preserved in these children. The decreased response to adenosine diphosphate may be a result of a low count and interference of red cells on the accretion of platelets on the electrodes. Because high concentrations of adenosine diphosphate were still required after hemodilution to achieve an aggregatory response close to normal, we speculate that leakage of endogenous adenosine diphosphate from red cells may have accounted for partial activation of the platelets, resulting in a relative refractory state to in vitro stimulation.

Aortic origin of right pulmonary artery: early detection by cross-sectional and color-Doppler-echocardiography in two infants submitted to successful surgical repair.

The aortic origin of the right pulmonary artery was recognized in two infants by cross-sectional echocardiography. The sub-costal short axis view was sufficient to make the diagnosis. The Doppler and color-Doppler techniques were useful in adding the hemodynamic information to the anatomical diagnosis. Early surgical correction was performed in the infants with success without needing to resort to cardiac catheterization.

Cross-sectional echocardiographic features of "absent" pulmonary valve. Report of two cases.

"Absence" of the pulmonary valve was recognized by cross-sectional echocardiography in two infants having relatively atypical clinical manifestations for this cardiac malformation. Both had associated lesions: tetralogy of Fallot and ventricular septal defect, respectively, which were also detected by this non-invasive technique. The findings which strongly suggested the diagnosis were the presence of a ridge of rudimentary pulmonary valvular tissue at the level of the pulmonary annulus and the aneurysmal dilation of the pulmonary arteries. The short axis view at the level of the great arteries was the best approach for visualization of these anatomical abnormalities. The parasternal long axis and sub-costal four-chamber views were also helpful in detecting the associated lesions. In both cases the diagnoses were confirmed at autopsy.

Correlation between gallium-67 imaging and endomyocardial biopsy in children with severe dilated cardiomyopathy.

Fourty-four patients (aged 10 months to 15 years) were assessed in a double-blind study to observe the correlation between myocardial uptake of 67-gallium and endomyocardial biopsy in the detection of moderate to severe myocardial inflammation. The sensitivity and specificity of gallium-67 imaging were 87 and 81%, respectively. Based on these findings, immunosuppressive therapy can be assigned to children with dilated cardiomyopathy and positive myocardial uptake, since moderate and severe myocardial inflammation may be detected by this non-invasive method.

Atresia of the left atrioventricular valve with patency of the aorta: anatomico-functional analysis of 23 patients.

We analyzed the findings in 23 patients with atresia of the left atrioventricular valve and a patent aorta seen in the period from January 1980 to July 1989. Having divided the cases according to the anatomical findings, we made a subsequent analysis of the clinical and surgical results with the aim of establishing the management most likely to diminish risks, still high, in treatment of this complex anomaly. From the anatomical viewpoint, three variants were observed. In the first, made up of 15 cases, there was absence of the left atrioventricular connexion. The characteristic finding in the second group, with five cases, was an imperforate left atrioventricular valve in the setting of concordant atrioventricular connexions. The third group, of these cases, was dominated by the presence of isomerism of the atrial appendages, both appendages being of left morphology in one case, and of right morphology in the other two. Further anatomical variation was then found in each group. Nine of the 15 with absence of the left atrioventricular connexion had the right atrium connected to a dominant left ventricle in presence of a rudimentary and incomplete right ventricle associated with discordant ventriculo-arterial connexions, all of them being in usual atrial arrangement and three with pulmonary stenosis. The remaining six in this first variant had the right atrium connected to a dominant right ventricle. In the five patients with imperforate left atrioventricular valves, two had discordant and three had concordant ventriculo-arterial connexions. In the three cases with isomerism, two had absence of the left atrioventricular connexion, with a dominant right ventricle. The last patient had an imperforate left atrioventricular valve and a discordant ventriculo-arterial connexion. From the functional viewpoint, there were 14 patients (10 with absence of an atrioventricular connexion, four with imperforate atrioventricular valve) with congestive heart failure and nine patients (five from the first, one from second, and three from the third variant) with hypoxia. Long-term follow-up (median 16.4 months--varying from 1 to 41 months--in the group with congestion and 27.7 months--varying from 12 to 57 months--in those with hypoxia) showed favorable clinical evolution in 11 (91%). We conclude that an anatomico-functional division can point towards the most appropriate management in this complex anomaly.

Choreoathetosis after cardiac surgery with hypothermia and extracorporeal circulation.

Eleven children, 4-48 months old, with congenital cyanotic heart defects developed choreoathetoid movements 2-12 days after cardiac surgery with hypothermia and extracorporeal circulation (ECC). The abnormal movements mainly involved the limbs, facial musculature, and tongue, leading to a severe dysphagia. The symptoms had an acute onset, after a period of apparent neurologic normality, and had a variable outcome. Of the nine children that survive, three had abnormal movements when last seen (41 days to 12 months of follow-up). The other six children had a complete regression of the choreoathetoid movements 1-4 weeks after onset. No specific finding was observed in the CT scans, cerebrospinal fluid examination, or EEG that could be related to the abnormal movements. Symptomatic therapy with haloperidol with or without benzodiazepines led to symptomatic improvement in six children, although there was no evidence that this treatment modified the evolution of the disease. The authors conclude that the choreoathetoid syndrome after cardiac surgery with deep hypothermia and ECC is an ill-defined entity requiring additional study to better understand its pathogenesis so that preventive measures can be taken to avoid a condition that can lead to permanent and incapacitating neurologic sequelae.

Circulating platelet aggregates indicative of in vivo platelet activation in pulmonary hypertension.

The authors investigated the existence of circulating cellular aggregates in 12 patients with moderate to severe pulmonary hypertension, using scanning electron microscopy. Peripheral venous blood was collected in the presence of 11.5 mM buffered ethylenediaminetetraacetic acid, in order to disperse freshly formed disaggregable aggregates. Irreversible aggregates represented by platelet clusters and/or platelet attachment to either leukocytes or red cells were identified in 7 patients with pulmonary hypertension. Endogenous platelet activation was further confirmed by a significant increase in plasma levels of beta-thromboglobulin in comparison with controls (33.8 +/- 14.1 vs 22.7 +/- 11.5 ng/mL respectively, p < 0.025). The presence of irreversible aggregates in the blood stream strongly suggests that cell-cell interactions actually occur in vivo in these patients. If so, therapeutic measures aimed at preventing in situ thrombosis and its consequences may be beneficial in this disorder.

Surgical treatment of the congenital fistulae of coronary arteries.

Six cases of coronary artery fistulae surgically treated are presented. All patient but one was male; the ages varied from 4 to 44 years. The fistulae originated from the left coronary artery in three cases from the right in two cases and from both arteries in one case. The draining heart chambers were the right atrium in three, the right ventricle in two and the pulmonary artery in one case. Associated lesions were present in three cases. One patient died on the early postoperative period and the evolution was satisfactory in five cases.

[Absence of right atrioventricular connection. Morphological and clinical presentation when the dominant ventricle is morphologically right]. / Ausência de conexão atrioventricular à direita. Apresentação morfológica e clínica quando o ventrículo principal é morfologicamente direito.

Absent right atrioventricular connection, with the left atrium connected to a dominant left-sided morphologically right ventricle is a rare situation. We report five cases with these anatomical features, with emphasis on the morphological and clinical aspects. Although this combination of lesions is very uncommon, the sequential segmental analysis can easily provide an accurate description of the anomaly.