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Between July 3, 1985, and February 24, 1994, a total of 55 infants underwent arterial switch procedures for the repair of transposition of the great vessels. Thirty-five infants had an intact ventricular septum and 20 had ventricular septal defects. To date, there have been three late deaths, one in the group with an intact ventricular septum and two in the group with a ventricular septal defect. Early postoperative complications included atrial dysrhythmias, prolonged ventilation, inability to close the sternum, and tension on the coronary arteries. Follow-up echocardiographic data for 44 patients indicate that pulmonary artery gradients are a worrisome postoperative problem, especially in infants who have ventricular septal defects.

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A six-week course in scientific writing and publishing was developed for pediatrics fellows at the University of Florida College of Medicine in 1984. It covered three areas: (1) grammar, syntax, and prose style; (2) construction of scientific papers; and (3) the submissions and review process. Increasing enrollment and the requests of course graduates led to the development of a second course, Advanced Scientific Writing; both courses are now offered annually. Class materials consist of texts in scientific writing, comprehensive syllabi, and handouts; the focus is on workshop activities, exercises, collaboration with peers, and individual consultations with the instructor. At the end of each course, participants complete detailed evaluation instruments, and the data obtained are used to modify the course's structure and content the following year.

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Cells from the cardiac neural crest are essential for the normal development of both the heart and the great vessels. If cardiac neural crest is ablated surgically from Hamburger-Hamilton stage 9 chicken embryos, they will develop anomalies of both the heart and great vessels that are similar to anomalies that occur in humans. In the absence of cardiac neural crest, another area of neural ectoderm (nodose placode) provides replacement cells that are less competent than those of the neural crest. In this study, both the cardiac neural crest and the nodose placodes have been surgically ablated. A syndrome of unusual prevalence (47%) and severity was found among the survivors of this surgery, which was characterized by a large undivided aorta that arched dorsally without right or left deviation to become the dorsal aorta. There was no other tributary to the formation of the dorsal aorta. There were no ducti arteriosi, and the pulmonary arteries were both ectopic and hypoplastic. The brachiocephalic arteries were asymmetric and hypoplastic. The association of the aorta with the anlagen of the thyroid and thymus glands, as well as with the inferior ganglion of the vagus nerve, indicated that the solitary surviving aortic arch artery is that of arch III in this syndrome. These results establish a biological limit of the plasticity of the neural ectoderm and give a probable cellular basis for a lethal congenital septal defect.

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The origin of the embryonic common pulmonary vein in terrestrial vertebrates is still uncertain. Most earlier studies in nonhuman embryos describe the vein as entering the sinus venosus. The currently prevailing view, however, based largely on the study of human material, is that the embryonic common pulmonary vein is associated with the left atrium from its inception. We recently observed the pulmonary vein entering the sinus venous part of the right atrium in several normal dog embryos of a stage comparable to horizon XIV in man (Streeter: Contrib. Embryol. Carnegie Inst. Wash., 31:53, 1945). In slightly older specimens the vein entered the left atrium just to the left of septum primum. This observation, and the fact that some atrial septal and pulmonary venous anomalies in man still await a plausible pathogenetic explanation, stimulated a restudy of the origin of the vein. The alligator was used because we already had prepared a large number of closely graded serially sectioned embryos for other purposes. Wax plate reconstructions clearly showed that the common pulmonary vein entered the left side of the sinus venosus. With the formation of the atrial septum, this part of the sinus venosus is "pinched off" and becomes incorporated into the left atrium, thus transferring the pulmonary venous ostium to that atrium.

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The pathologic anatomic features and associated cardiovascular anomalies of 9 patients with anomalous origin of 1 pulmonary artery (PA) from the ascending aorta seen at the University of Florida and 99 previously reported cases were analyzed. Anomalous origin of the right PA was much more common than anomalous origin of the left PA. The anomalous right PA usually arose from the posterior aspect of the ascending aorta close to the aortic valve. Less commonly, it originated from the lateral ascending aorta just proximal to the innominate artery. Patent ductus arteriosus and aorticopulmonary septal defect were commonly associated with anomalous origin of the right PA; other cardiovascular anomalies were rare. In contrast, tetralogy of Fallot and aortic arch anomalies, e.g., right aortic arch and anomalous origin of the subclavian artery, were common in anomalous origin of the left PA. An association with DiGeorge syndrome, frequently noted with persistent truncus arteriosus, was not seen with anomalous origin of a PA from the ascending aorta. The observations indicate that anomalous origin of the right PA and anomalous origin of the left PA are pathogenetically unrelated to each other and both are unrelated to persistent truncus arteriosus. Moreover, anomalous origin of the right PA arising close to the innominate artery is thought to be pathogenetically distinct from the type that arises close to the aortic valve. These pathogenetic relations should be considered in epidemiologic studies of congenital heart disease.

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We gathered data on 39 victims of Eastern coral snake bite over a 12-year period. The most common situation resulting in snakebite was erroneous identification of the snake as the nonpoisonous scarlet king snake. While no patient died, several experienced severe envenomation, including bulbospinal respiratory paralysis. We found that neurologic symptoms may be delayed for 12 hours, and then may be precipitous. Envenomation occurs in 75% of the persons bitten by a coral snake. Antivenin is effective and should be intravenously administered early to patients who have been bitten by a positively identified coral snake, depending on the clinical presentation.

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The pathologic anatomic features and associated cardiac anomalies of 13 patients with aorticopulmonary septal defect (APSD) and of 236 previously reported cases were analyzed. Morphologically, 3 types of APSD were distinguished: a defect with a more or less circular border located about halfway between the arterial valves and the bifurcation of the pulmonary trunk; a similarly located defect in which the border represents a helix; and a usually large defect in which there is no posterior (distal) border. The appearance of these 3 types of defects suggests a different developmental mechanism for each. Approximately half of the cases of APSD are not associated with other cardiovascular anomalies. Of the anomalies that do occur, anomalous origin of a coronary artery from the pulmonary trunk and interruption of the aortic arch (IAA) type A or severe preductal coarctation are seen far more often than expected. An association with DiGeorge syndrome, frequently noted with persistent truncus arteriosus (TA) and IAA type B, was not seen. Certain cardiac anomalies often seen with TA are rarely seen with APSD, and defects often seen with APSD are rarely seen with TA. These observations indicate that APSD and TA are pathogenetically unrelated even though located in the same region of the heart and, unlike TA and IAA type B, APSD is probably not due to a developmental error involving the neural crest.

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Severe myonecrosis was found at autopsy in a fatal case of envenomation by Crotalus horridus atricaudatus. The degree and extent of rhabdomyolysis were independent of the site of muscle sampling, being no more advanced at the site of envenomation. We conclude that myonecrosis was not enhanced by increased interstitial pressure.

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To investigate the contribution of cranial neural crest cells to the developing cardiovascular system in the chick embryo, cauterization of various regions of cranial neural crest was performed. Five regions may be distinguished, each of which contributes mesenchyme to pharyngeal (branchial) arches 1 through 4 and 6. Ablation of arch 3, 4, and 6 regions resulted in a high incidence of persistent truncus arteriosus (PTA) associated with anomalies of the aortic arch. Dextroposed aorta (DPA) or anomalies of the inflow tract were found in all ablation groups. Although anomalies of the aortic arch arteries were induced in all ablation groups and were usually associated with intracardiac anomalies, those of the third and right fourth aortic arch were most frequent in the arch 4 and arch 4 + 6 groups. Anomalies of the sixth aortic arch were most frequent after extensive ablations that included the arch 6 region. We speculate that PTA is a direct result of the decreased population of mesenchymal cells derived from the arch 3 through 6 neural crest regions. DPA or anomalies of the inflow tract may be related to altered hemodynamics due to anomalies induced by neural crest ablation. Anomalies of the aortic arch arteries may be caused by either the direct or indirect process.

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One hundred sixty-one cases of DiGeorge syndrome (111 previously reported in which details concerning individual patients were given and 50 observed) were analyzed for occurrence and type of cardiovascular anomalies. Only 5 patients had a normal heart. Interrupted aortic arch type B was the major anomaly in 48 patients and persistent truncus arteriosus in 37. Therefore, in about half of the patients with DiGeorge syndrome the major anomaly was one that is rare. Conversely, of those patients with interrupted aortic arch, 68% had DiGeorge syndrome, as did 33% of all patients with truncus arteriosus. Although tetralogy of Fallot was also seen often in DiGeorge syndrome (10 patients), these cases represented less than 2% of the total number of cases of tetralogy of Fallot. Similarly, less than 1% of children with isolated ventricular septal defect or transposition of the great arteries had DiGeorge syndrome. The primary cardiovascular anomaly always involved the aortic arch system or the arterial pole of the heart. Recent studies show that neural crest cells play a crucial role in development of pharyngeal (bronchial) pouch derivatives, e.g., thymus and parathyroid glands, as well as the aortic arches and the truncoconal part of the heart. These studies and present observations support the view that DiGeorge syndrome and the associated cardiovascular anomalies are due to an abnormal developmental process involving the neural crest. Curiously, no instances of aortopulmonary septal defect or anomalous origin of a pulmonary artery from the ascending aorta (hemitruncus) have been associated with DiGeorge syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

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Removal of premigratory neural crest over somites 1 through 3 in chick embryos has been shown previously to result in a significant incidence of persistent truncus arteriosus. In the present study, single somite-length pieces of premigratory neural crest were removed unilaterally at slightly different embryonic ages. These lesions resulted in a number of different heart defects. Two defects, ventricular septal defect and double outlet right ventricle, were significantly correlated with the location of neural crest removed. The stage at which the ablation was performed was important in determining the incidence but not the type of defects.

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Anatomic variation of the infundibular septum was studied in transposition of the great arteries with ventricular septal defect in 23 hearts and double-outlet right ventricle with anterior position of the aorta in two hearts. Anterior displacement of the infundibular septum (i.e., "false" Taussig-Bing heart) was associated with coarctation or interruption of the aortic arch in 88% of the cases, whereas posterior displacement resulted in subpulmonary narrowing in 100% of the cases. Anterior displacement makes intraventricular rerouting from the left ventricle to the aorta difficult because of a long oblique route. In addition, the right ventricular cavity becomes smaller after closure of the ventricular septal defect. Therefore, arterial switch accompanied with transatrial or transpulmonary closure of the defect without ventriculotomy is recommended. In hearts with posterior displacement of the infundibular septum, the anterosuperior rim of the defect is difficult to approach through the tricuspid valve, and the route from the left ventricle to the aorta is rather straight. Hence, the Rastelli procedure is preferable. In hearts without displacement of the infundibular septum, either arterial or atrial switch with transatrial closure of the ventricular septal defect is applicable.

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The pathologic anatomic features and associated cardiac anomalies of 63 cases of interruption of the aortic arch (IAA) type A (54 reported and 9 observed) and 145 cases of type B (124 reported and 21 observed) were analyzed and compared with those seen in 57 autopsy cases of infant coarctation of the aorta (CA). There was no significant sex predominance within the 3 groups and the prognosis without surgery was uniformly poor. Ventricular septal defect was much more common in IAA type B than in type A or CA. Anomalous origin of the subclavian artery and DiGeorge syndrome were commonly associated with IAA type B but were rare in type A and CA. Transposition of the great arteries and double-inlet left ventricle are less common in IAA type B than in types A and CA. On the basis of these findings and the observation by Le Lièvre and Le Douarin that neural crest cells contribute significantly to the formation of the visceral arch system and associated organs, we postulate that IAA type B may be a manifestation of a developmental error involving the neural crest, as is the DiGeorge syndrome. We believe IAA type A and CA to be closely related anomalies that may be prenatally acquired and pathogenetically distinct from IAA type B.

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In 14 of 21 infant hearts (66%) with aortic arch interruption between the left common carotid and left subclavian arteries (type B of Celoria and Patton), the right subclavian artery (SA) arose anomalously. In 9 (43%) it arose from the descending aorta and in 1 heart from the right pulmonary artery (5%). In 4 hearts (19%), it arose high in the neck from the right common carotid artery as a trifurcation with the internal and external carotid arteries, an anomaly not previously reported. In these latter cases, the SA descended down the neck to enter the right arm, with the right recurrent laryngeal nerve coursing around its take-off. Anomalous origin of the right SA is common in type B aortic arch interruption, and we believe this to be the result of a strong tendency for both fourth aortic arches to disappear early in development. If involution occurs in embryos of less than 14 mm crown-rump length, before the right ductus caroticus and dorsal segment of the right sixth arch have become attenuated, 3 alternate routes are available to the embryo to form a right SA.

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