Pathogen resistance genes represent some of the most abundant and diverse gene families found within plant genomes. However, evolutionary mechanisms generating resistance gene diversity at the genome level are not well understood. We used the complete Arabidopsis thaliana genome sequence to show that most duplication of individual NBS-LRR sequences occurs at close physical proximity to the parent sequence and generates clusters of closely related NBS-LRR sequences. Deploying the statistical strength of phylogeographic approaches and using chromosomal location as a proxy for spatial location, we show that apparent duplication of NBS-LRR genes to ectopic chromosomal locations is largely the consequence of segmental chromosome duplication and rearrangement, rather than the independent duplication of individual sequences. Although accounting for a smaller fraction of NBS-LRR gene duplications, segmental chromosome duplication and rearrangement events have a large impact on the evolution of this multigene family. Intergenic exchange is dramatically lower between NBS-LRR sequences located in different chromosome regions as compared to exchange between sequences within the same chromosome region. Consequently, once translocated to new chromosome locations, NBS-LRR gene copies have a greater likelihood of escaping intergenic exchange and adopting new functions than do gene copies located within the same chromosomal region. We propose an evolutionary model that relates processes of genome evolution to mechanisms of evolution for the large, diverse, NBS-LRR gene family.

https://www.genetics.org/content/genetics/165/1/309.full.pdf

Genome-level evolution of resistance genes in Arabidopsis thaliana

2013 is a remarkable year in cardiovascular medicine from a historical point of view. It can be considered a crown year for non-invasive clinical cardiovascular imaging as we can look back on 60 years of echocardiography, 40 years of nuclear cardiology, 30 years of cardiovascular magnetic resonance imaging, and 30 years of cardiac computed tomography. In previous Editor’s Comments, 60 years of echocardiography, 40 years of nuclear cardiology, and 30 years of cardiovascular magnetic resonance have been described (Parts I, II, and II) [1–3]. In this Editor’s Comment (Part IV) we will briefly look back to the roots of cardiac computed tomography and its main achievements over the past 30 years.

/pdf/crown-years-for-non-invasive-cardiovascular-imaging-part-iv-9rg4lf2o12.pdf

Crown years for non-invasive cardiovascular imaging (Part IV): 30 years of cardiac computed tomography.

/pdf/coronary-artery-fistulas-in-adults-clinical-and-coronary-1k6ayyzths.pdf

Coronary Artery Fistulas in Adults Clinical and Coronary Angiographic Aspects.

Central venous catheter (CVC) is one of the most commonly placed invasive devices in critical care setup. Its placement can be associated with many technical complications like bleeding, pneumothorax, arterial puncture and infection. Furthermore technical and anatomical variations, unfavorable body habitus can lead to malpositioning of CVC within venous system even when they are placed under radiological guidance. If not addressed timely, malpositioning can be associated with poor catheter functioning and serious complications like vessel erosion, bleeding, thrombosis. Presence of congenital venous anomalies can be a rare cause of CVC malpositioning. We report a case of young female in whom CVC placed through left internal jugular venous (IJV) route accidentally entered into a left upper pulmonary vein through partial anomalous pulmonary venous connection (PAPVC) with the left brachiocephalic vein. Post insertion chest radiograph showed unusual curvilinear course of the left IJV access towards left pulmonary hilum. The diagnosis was clinched after contrast enhanced computed tomography delineated the previously undiagnosed venous anomaly in the patient. There is no report of CVC malposition into the pulmonary vein in medical literature making it unique and first of its kind. Malpositioned CVC can thus lead to revelation of asymptomatic congenital vascular anomalies in a completely unrelated clinical setting.

/pdf/accidental-catheterization-of-left-partial-anomalous-3vem41wy75.pdf

Accidental Catheterization of Left Partial Anomalous Pulmonary Venous Connection (PAPVC): A Rare Instance of Central Venous Access Malpositioning

Partial anomalous pulmonary venous return (PAPVR) is a rare congenital abnormality in which 1 to 3 of the pulmonary veins connect to the right atrium rather than the left atrium. In this synthesis of the literature on PAPVR of the left upper lobe, we attempt to illustrate this clinical entity using a case detected incidentally on chest computed tomography, explain the anatomical aspects of this anomaly, and summarize the reported incidence and etiology of left-sided PAPVR. Lastly, differential diagnoses, clinical relevance, and management of left-sided PAPVR are presented. The identification of this variant is important, as it may have serious consequences.

/pdf/incidental-finding-of-anomalous-pulmonary-venous-return-of-13kp9eemzk.pdf

Incidental Finding of Anomalous Pulmonary Venous Return of the Left Upper Lobe, a Rare Anatomical Variation.

A 40-year-old woman presented with dyspnoea, chest pain and fatigue. Her medical history was unremarkable. An early systolic ejection murmur was heard in the 3D left inter-costal space. Chest X-ray revealed normal cardiothoracic ratio with an anomalous vessel adjacent to the left pulmonary hilum. Echocardiography and exercise tolerance test were normal. Right heart catheterisation revealed normal pulmonary pressures with normal cardiac output. CT scan and MRI of the thorax were diagnostic for an aberrant pulmonary venous connection between the left lower lobe pulmonary vein and the left brachiocephalic vein without atrial septal defect. She was treated conservatively and remained well.

/pdf/clinical-and-diagnostic-features-of-partially-anomalous-26n9y4jjy7.pdf

Clinical and diagnostic features of partially anomalous pulmonary venous connection in an adult female patient: a case report and review of the literature.

A female patient, 36 years of age, with a metastasised left breast cancer received several courses of chemotherapy for aggressive local tumour growth and multiple metastatic activity. In the current patient, surgical ablation of the left breast was carried out. Also loco-regional radio-therapy was conducted. To facilitate the administration of chemotherapy courses and prevent thrombophlebitis a vascular access port (port-a-cath) was surgically inserted via the right subclavian vein. After a few successful administrations of chemotherapeutic drugs the vascular port stopped functioning. It was demonstrated that a detached catheter fragment had dislodged into the right ventricle. Successful percutaneous, transvenous removal of the entrapped catheter fragment by the Gooseneck retrieval loop snare from the right ventricle was performed via the right femoral vein access. The procedure was uncomplicated and the patient tolerated the procedure well.

C. M. Stassen

Papers

Clinical and diagnostic features of partially anomalous pulmonary venous connection in an adult female patient: a case report and review of the literature.

Percutaneous transvenous retrieval of intracardiac port-a-cath catheter fragment: a case report.