Post-glacial habitat release and incipient speciation in the genus Delphinus.

The role of ecological and changing environmental factors in the radiation of species diversity is a fundamental question in evolutionary biology. Of particular interest is the potential for these factors to determine the boundary between what we would consider differentiation among populations and incipient speciation. Dolphins in the genus Delphinus provide a useful test case, exhibiting morphological variation in beak length, coloration and body size across their wide geographic distribution, and in particular among coastal and more pelagic habitats. Two species have been proposed, D. delphis and D. capensis, but morphologically similar allopatric populations are not monophyletic, indicating that the mostly coastal 'long-beaked' D. capensis form is not a single globally distributed species. However, the sympatric populations in the Eastern North Pacific currently designated as these two species are both morphologically and genetically differentiated. Here we use microsatellite DNA and mitochondrial DNA markers to investigate the evolutionary mechanisms that led to this incipient speciation event. We used coalescent and assignment methods to investigate the timing and extent of reproductive isolation. Our data indicate that although there is some level of on-going gene flow, the putative species found in the Eastern North Pacific are reciprocally monophyletic. The timing of isolation appears to be associated with regional changes in paleoceanographic conditions within the Holocene timeframe.

Taquiarritmias supraventrículares fetales refractarias al tratamiento inicial / Fetal supraventricular tachyarrhythmias refractory to initial therapy

Las arritmias fetales representan un motivo infrecuente de ingreso ala unidad de cuidados intensivos. Se presenta tres casos de gestantes entre 27 y 32 semanas, con el diagnóestico de taquiarritmias supraventriculares fetales sostenidas, que exhibían fracaso en el intento inicial de reversión con digoxina. Dos casos con taquicardia sapraventricular respondieron favorablemente cuando se asoció flecainida. Un feto hidrópico con aleteo auricular y bloqueo 2:1 no revirtió con la associón de flecainida ni amiodarona a la digoxina y requirió la interrupsión de la gestación en la 30 ¬ semana. El neonato presentó disfunción tiroidea transitória atribuída a la administración de amiodarona. (AU)

Taquiarritmias supraventrículares fetales refractarias al tratamiento inicial / Fetal supraventricular tachyarrhythmias refractory to initial therapy

Las arritmias fetales representan un motivo infrecuente de ingreso ala unidad de cuidados intensivos. Se presenta tres casos de gestantes entre 27 y 32 semanas, con el diagnóestico de taquiarritmias supraventriculares fetales sostenidas, que exhibían fracaso en el intento inicial de reversión con digoxina. Dos casos con taquicardia sapraventricular respondieron favorablemente cuando se asoció flecainida. Un feto hidrópico con aleteo auricular y bloqueo 2:1 no revirtió con la associón de flecainida ni amiodarona a la digoxina y requirió la interrupsión de la gestación en la 30 ª semana. El neonato presentó disfunción tiroidea transitória atribuída a la administración de amiodarona.

Bidirectional cavopulmonary shunt in patients with multiple risk factors.

BACKGROUND: Twenty-five patients in whom a modified Fontan operation was deferred because of multiple risk factors underwent a bidirectional cavopulmonary shunt. Two or more of the following risk factors were present in all: age less than 1 year, severe pulmonary artery distortion, impaired left ventricular function, subaortic obstruction, anomalous systemic-pulmonary venous connection, atrioventricular valve incompetence, and increased mean pulmonary artery pressure. METHODS: Additional procedures included take-down of systemic-pulmonary artery shunt, atrial septectomy, pulmonary artery reconstruction, bulboventricular foramen enlargement, and atrioventricular valve repair. RESULTS: There were three hospital deaths (12%). Mean follow-up is 21 months. There was no late mortality. Mean oxygen saturation increased from 71% to 83%. Results obtained from pulmonary artery reconstruction, enlargement of bulboventricular foramen, and atrioventricular valve repair were satisfactory for the patients in whom these risk factors were present preoperatively. Ventricular function also improved in the survivors in whom it was previously deteriorated, this being related to the suppression of the sources of ventricular volume overload. CONCLUSIONS: In this risk group of patients for a modified Fontan operation, a bidirectional cavopulmonary shunt provided adequate palliation at reasonable low risk. Early bidirectional cavopulmonary shunt would minimize complications originating from systemic-pulmonary shunts such as pulmonary artery distortion and the potential harm of chronic ventricular volume overload.

Infective endocarditis in children: clinical analyses and evaluation of two diagnostic criteria.

A new diagnostic schema for infective endocarditis (IE), the Duke criteria, has been compared with the previously published criteria of von Reyn in adult patients. This study was designed to analyze the clinical characteristics of a group of pediatric patients with IE and to compare the diagnostic efficiency of both sets of criteria. We reviewed retrospectively the clinical records of 38 patients, 22 with predisposing heart disease (Subgroup A) and 16 with no known cardiologic abnormality (Subgroup B). Ventricular septal defect was the most frequent preexisting heart disease (31.8%) and central venous catheters were the most frequent predisposing factor (68.7%). Comparison of the clinical features between subgroups (A vs. B) showed differences only for the presence of a new regurgitant murmur (9% vs. 44%, P < 0.05) and a hemoglobin value < or = 10 g/dl (50% vs. 94%, P < 0.05). The most frequent microorganisms isolated were viridans streptococci (36%) in Subgroup A and Staphylococcus aureus (50%) in Subgroup B. Of the 6 pathologically confirmed cases all would have been classified as clinically definite by the Duke criteria, as compared with 2 of 6 being defined as probable and one being rejected by von Reyn criteria. Of the 32 cases clinically defined 19 (59%) were classified as definite by the Duke criteria, and 11 (34%) were probable by the von Reyn criteria (difference 25%, P < 0.01). Although no case of IE was rejected by Duke criteria, 8 (25%) were rejected by von Reyn criteria (difference 25%, P < 0.01), with all 8 classified as possible by Duke criteria. We conclude that the Duke criteria were superior to the von Reyn criteria for the diagnosis of pediatric IE, including more cases as definite and significantly fewer cases as rejected.