Surgical approach with minimally invasive intervention in lusoria dysphagia.

The lusoria artery has a prevalence of 0.5-2% in the general population. The abnormal development of the aortic arch forms vascular rings around the trachea and esophagus, causing pressure on them and leading to characteristic symptoms such as chest pain, difficulty breathing, and/or swallowing. Conventionally, only the subclavian artery was severed to release the esophagus, as done in neonates. However, this can lead to long-term hypotrophy of the thoracic limb. The surgical intervention remains controversial, with limitations, and it is only to be performed when the patient presents with symptoms. In the following two cases, a two-stage minimally invasive approach is described: first, a left lateral minithoracotomy for lusoria artery sectioning, and second, a supraclavicular approach for reimplantation into the right carotid artery.

La arteria lusoria tiene una prevalencia del 0.5% al 2% en la población general. Se trata de un arco aórtico izquierdo con arteria subclavia derecha aberrante, resulta de la regresión del cuarto arco derecho y la aorta dorsal derecha proximal. La anormalidad del desarrollo del arco aórtico forma anillos vasculares alrededor de la tráquea y el esófago ocasionando una presión hacia ellos y dar clínica característica de dolor torácico, dificultad para la respiración y/o deglución. Tradicionalmente solo seccionábamos la subclavia para liberar el esófago como se realiza en la edad neonatal, sin embargo, esto puede condicionar hipotrofia del miembro torácico a largo plazo. La intervención quirúrgica sigue siendo controvertida, con limitaciones y se decide realizarse cuando el paciente presenta sintomatología. En este reporte de dos casos se describe un abordaje por incisiones mínimamente invasiva en dos tiempos: primero por mini toracotomía lateral izquierda para sección de la arteria lusoria; segundo abordaje supraclavicular para reimplantación en la carótida derecha.

The nucleosomal barrier to promoter escape by RNA polymerase II is overcome by the chromatin remodeler Chd1.

RNA polymerase II (PolII) transcribes RNA within a chromatin context, with nucleosomes acting as barriers to transcription. Despite these barriers, transcription through chromatin in vivo is highly efficient, suggesting the existence of factors that overcome this obstacle. To increase the resolution obtained by standard chromatin immunoprecipitation, we developed a novel strategy using micrococcal nuclease digestion of cross-linked chromatin. We find that the chromatin remodeler Chd1 is recruited to promoter proximal nucleosomes of genes undergoing active transcription, where Chd1 is responsible for the vast majority of PolII-directed nucleosome turnover. The expression of a dominant negative form of Chd1 results in increased stalling of PolII past the entry site of the promoter proximal nucleosomes. We find that Chd1 evicts nucleosomes downstream of the promoter in order to overcome the nucleosomal barrier and enable PolII promoter escape, thus providing mechanistic insight into the role of Chd1 in transcription and pluripotency. DOI: http://dx.doi.org/10.7554/eLife.02042.001.