Stenosis of pulmonary veins with ventricular septal defect. A cause of premature pulmonary hypertension in infancy

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Congenital heart disease in the neonate: results of surgical treatment

All 212 neonates undergoing cardiac surgery at this hospital during the 5-year period from 1976 to 1980 inclusive were reviewed. Forty required open heart surgery with 23 (57%) deaths. One hundred and seventy-four neonates underwent non-bypass procedures and could be divided into three groups: group 1 (82 patients) had inadequate pulmonary blood flow, group 2 (33 patients) had increased pulmonary blood flow or inadequate mixing, and group 3 (59 patients) had coarctation of the aorta, alone or with associated lesions. Forty-four (25%) of the neonates undergoing non-bypass procedures died. Two required bypass surgery later in the first month of life. Metabolic acidosis and the need for preoperative respiratory support were appreciably greater in non-surviving patients. The spectrum of diagnoses encountered and types of operative procedures performed are analysed.

Use of a subpulmonary ventricular chamber in the Fontan circulation

In order to study the usefulness of incorporating a subpulmonary ventricular chamber (SPVC) in the Fontan circulation, we compared the hemodynamics of 18 patients who underwent an atriopulmonary connection with those of 17 patients with an atrioventricular connection. Early postoperatively, regardless of whether an SPVC was incorporated or not, the mean pulmonary artery pressure was not higher than the mean right atrial pressure in any of our patients. The stroke work of the right heart was at best zero, and pressure tracings showed an a wave in the pulmonary artery (right atrium-dependent circulation). If an additional gradient was interposed between the right atrium and pulmonary artery, the effective stroke work of the right heart might be negative and the work curve have a negative slope. This can occur irrespective of the use of an SPVC. In the long term, if it grows sufficiently, an SPVC can sometimes provide a right ventricle-dependent pulmonary circulation with a more normal hemodynamic pattern (mean right atrial pressure less than mean pulmonary artery pressure). We concluded that an SPVC should be used in Fontan's circulation, provided that an obstruction-free atrioventricular connection can be established.

Cellular chemical indices of right ventricular protection in children

Myocardial preservation during open heart surgery in children was studied using biopsies of the right ventricle taken at the beginning and end of a bypass with a Tru-Cut biopsy needle. Three assessments were used: (1) semi-quantitative cytochemical grading of Baker's acid haematein reaction, and the distribution of succinate dehydrogenase and myosin ATPase; (2) microdensitometry of the succinate dehydrogenase activity; and (3) quantitative birefringence measurements to assess the response of the myocardial fibres to ATP and calcium. For each assessment, the values at the beginning and end of the bypass were compared. In a series of 42 children, two died in low cardiac output and three others required substantial inotropic support. No patient showed deterioration in the overall cytochemical assessment. Two patients showed deterioration in birefringence, one died and one had low cardiac output. The remaining three patients who had post-operative problems had low birefringence values at the beginning of bypass. Thirty-two patients were used for the microdensitometric assays, one died and three required substantial inotropic support. Succinate dehydrogenase activity decreased significantly during bypass in only two patients. One of these died and the other required substantial inotropic support.

Pulmonary atresia and intact ventricular septum: surgical management based on a revised classification

Sixty patients with pulmonary atresia and intact ventricular septum (PA:IVS) presenting from 1970 to 1980 are reviewed. Three groups of patient are discussed: those with tripartite right ventricles, those with no trabecular portion to the cavity, and those with neither trabecular nor infundibular portions. The decrease in early mortality for neonates with PA:IVS since 1977 (one death in 15 patients) supports our current management policy of preoperative prostaglandin E1 infusion with transpulmonary valvotomy (for patients with an infundibular cavity) combined with a left modified Blalock-Taussig shunt using a Gore-Tex prosthesis. Tricuspid valve growth, estimated by serial angiograms in 12 patients, was greater if right ventricle-to-pulmonary artery continuity was established. Later definitive repair was attempted in nine patients, with two early deaths; five underwent right ventricular outflow tract reconstruction and four had modified Fontan procedures. Neonates with critical pulmonary stenosis are also discussed. Their neonatal mortality (nine deaths in 20 patients) was similar to that of comparable patients with PA:IVS, but their actuarial survival at 5 years (55%) was superior (36% at 5 years).

Pulmonary atresia and intact ventricular septum: a revised classification

The dismal outlook for patients with pulmonary atresia with intact ventricular septum may be related to associated right ventricular hypoplasia. Study of 32 autopsy specimens and 46 angiocardiograms of neonates with this lesion suggested that the cavitary hypoplasia was related to massive hypertrophy of the right ventricular wall. This hypertrophy was sufficient to obliterate the trabecular and/or infundibular portion of the ventricular cavity entirely in one-third of the cases; this observation forms the basis for a revised classification of these hearts. Three autopsies and 14 angiograms of neonates with critical pulmonary stenosis were examined. Hearts with obliterated infundibular and trabecular cavities had thicker walls and smaller tricuspid valves, as estimated angiographically or at autopsy, than those in which the normal three portions of the ventricular cavity were represented.

Purification and properties of protocatechuate 3,4-dioxygenase from Pseudomonas putida. A new iron to subunit stoichiometry

Protocatechuate dioxygenase has been isolated from Pseudomonas putida. This new species of protocatechuate dioxygenase has been characterized and compared with the enzyme from Pseudomonas aeruginosa. The enzyme reported here has visible absorption, circular dichroism, electron paramagnetic resonance, and Raman spectroscopic properties virtually identical to those for protocatechuate dioxygenase from P. aeruginosa. However, the molecular weight and iron:subunit stoichiometry differ. Protocatechuate dioxygenase from P. putida has a molecular weight of 200,000 and contains 4 alpha subunits of 23,000 daltons, 4 beta subunits of 26,500 daltons, and 4 ferric irons suggesting that the enzyme is a tetramer of (alpha beta Fe+3) catalytic units. Protocatechuate dioxygenase from P. aeruginosa has been reported to have a Mr = 700,000, consisting of 16 alpha subunits of 22,500 daltons, 16 beta subunits of 25,000 daltons, and 8 ferric irons (Yoshida, R., Hori, K., Fujiwara, M., Saeki, Y., Kagamiyama, H., and Nozaki, W. (1976) Biochemistry 15, 4048-4053). This enzyme is thought to be an octamer of (alpha 2 beta 2 Fe+3) catalytic units, although reconstitution with extra iron will somewhat increase its activity. Using stopped flow techniques, we have shown that essentially all of the iron in the P. putida enzyme is catalytically active. This suggests that the minimal catalytic unit of all non-heme iron intradiol dioxygenases is an (alpha beta Fe+3) structure.

The reaction of oxygen with protocatechuate 3,4-dioxygenase from Pseudomonas putida. Characterization of a new oxygenated intermediate

The reactions of protocatechuate dioxygenase (protocatechuate:oxygen 3,4-oxidoreductase, EC 1.13.11.3) with substrates and oxygen have been studied at 4 degrees C using rapid kinetic techniques. In this study, two oxygenated intermediates were kinetically and spectrally characterized. The rate of oxygen addition to the enzyme-substrate complex was determined to be 5 X 10(5) M-1 s-1. This oxygenated complex rapidly converts (450 s-1) to another spectrally identifiable compound which then breaks down into free enzyme and the product, beta-carboxy-cis,cis-muconic acid. To carry out these experiments properly, it was necessary to use hyperbaric oxygen, thus obtaining approximately 6 mM final concentration of oxygen. The procedure is described in this work. It was also shown that the normally slow substrate, dihydroxyphenyl propionate, when reacted with the enzyme and oxygen, rapidly forms two sequential intermediates. However, the second intermediate was not spectrally the same as that observed with protocatechuate, but was more like that of enzyme-product complexes. Similar, although less extensive, studies using the protocatechuate dioxygenase from Pseudomonas aeruginosa showed that very analogous behavior occurred with both substrates as did with the Pseudomonas putida enzyme.

Correction of isolated secundum atrial septal defect in infancy

Although it is a common congenital cardiac lesion, secundum atrial septal defect (ASD) rarely presents in infancy. Its natural history in the first two decades of life is generally benign. Reports of symptomatic ASD in early childhood stress the place of conservative management, and recommend that the operation should be deferred until school age. Few accounts of the indications for surgery in infancy exist. We present our experience of 6 patients who failed to respond adequately to conservative treatment and required operation for intractable heart failure due to isolated secundum ASD in the first year of life. As their presentation and physical signs were not typical of ASD seen in later childhood, they presented problems both of diagnosis and management.

Leg function after radiotherapy for Ewing's sarcoma

Twenty-nine patients with Ewing's sarcoma of the lower extremity who survived for two or more years following therapy (5000 rad locally and systemic chemotherapy) were studied to assess functional status of the affected leg. Twenty-two of twenty-nine were alive and were reexamined; the deceased patients were evaluated by record review. Twenty-two of the twenty-nine had serial radiographs, which were reviewed to assess growth change induced by radiation. The living patients were divided on the basis of clinical examination into four functional groups with Group I comprising patients with minor functional limitations and leg length discrepancy 1.5 cm or less. Group II patients had moderate functional limitations with 2.5-cm leg-length discrepancy or less. Group III patients had severe functional limitations with up to 4-cm leg length discrepancy. Group IV patients had severe complications, sufficient enough to warrant amputation. Thirteen of twenty-two patients were classified as functional Group I, five as Group II, three as Group III, and one as Group IV. Radiographic changes in growing bone did not correlate with functional results. Although a femoral fracture and an age less than 16 years at diagnosis were found to be less favorable prognostic factors for the functional treatment result, these results show that neither femoral location nor young age justify primary amputation for Ewing's sarcoma of the lower leg extremity.

Clinical and laboratory evaluation of the Shiley S-100-A oxygenator-heat exchanger

A new oxygenator the Shiley S-100-A has been evaluated. It incorporates a heat exchanger based on an anodised aluminium tube which replaces the polyurethane coated tube of the previous S-100 model. Data from 46 patients perfused with the Shiley S-100-A were reviewed and compared with figures derived from a previous group of 225 patients in whom the S-100 model was used. The gas transfer capacity of the S-100-A model is very good and comparable to that of the S-100 oxygenator at a low gas flow/blood flow ratio. However both "in vitro" and "in vivo" studies confirmed the superiority of the heat exchange capacity of the S-100-A model. The times required for cooling (from 36.5 to 29.6 degrees C) and rewarming (from 29.6 to 37 degrees C) for an adult patient of average build were 9.1 and 26 minutes for the S-100 model and 6.7 and 15 minutes for the S-100-A model respectively. In a separate group of patients cooled to and rewarmed from 26 degrees C the cooling and rewarming times were 12.4 and 23 minutes respectively.

Source of residual Bohr effect in hemoglobin oxidation

The hemoglobin oxidation Bohr effect is larger than the ligation Bohr effect, even when the former is corrected for any ionization of the water molecule bound to the ferric iron of methemoglobin. This residual oxidation Bohr effect is here shown to be solely caused by the influence of the positively charged ferriheme, and is abolished when the oxidized heme binds an anion. This result frees the formal equivalence of hemoglobin ligation and oxidation from the last apparent experimental discrepancy.

Linearity of the hemoglobin oxidation bohr effect

The hemoglobin oxidation Bohr effect below pH 7 is essentially proportional to the fraction of hemes oxidized, just as the ligation Bohr effect is proportional to fractional heme ligation. The reported nonlinear proton release during oxidation [(1965) J. Biol. Chem. 240, 3317-3324] is shown to be an artifact resulting from the use of ferricyanide as oxidant. Published forms of the two-state allosteric transition model for hemoglobin function have used several proton linkage schemes, and none are compatible with a linear proton release upon oxidation.

Redox equilibria of liganded forms of methemoglobin

We have examined the redox equilibria of azidomethemoglobin (low-spin) and fluoromethemoglobin (high-spin). We have derived a modified Hill equation which includes the tetramer--dimer equilibrium of the oxidized form, and also generalized the two-state model to incorporate ligand binding to the ferriheme. The pH dependence of the redox Hill's constant for fluoromethemoglobin is the same as that for methemoglobin, demonstrating that this dependence and the marked cooperativity achieved (n = 2.2) are not coupled to changes of the ferriheme spin state. The redox Hill's constant for azidomethemoglobin, however, is as large as the oxygenation Hill's constant (n approximately 2.7) and is also roughly pH independent.

Coboglobins: heterotropic linkage and the existence of a quaternary structure change upon oxygenation of cobaltohemoglobin

Cobaltohemoglobin prepared from horse hemoglobin retains the full heterotropic linkage properties of the normal iron hemoglobin, including both the Bohr and phosphate effects. From this result, and the known connection between heterotropic linkage properties and hemoglobin conformational change, it is concluded that cobaltohemoglobin undergoes a quaternary structure transition upon oxygenation. Thus, the stereochemical changes that occur upon oxygen binding to cobalt, as well as to iron, must be compatible with the mechanism triggering such a transition.

Thymoma

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