Evaluation of simulation training in cardiothoracic surgery: The Senior Tour perspective

OBJECTIVE: The study objective was to introduce senior surgeons, referred to as members of the "Senior Tour," to simulation-based learning and evaluate ongoing simulation efforts in cardiothoracic surgery. METHODS: Thirteen senior cardiothoracic surgeons participated in a 2½-day Senior Tour Meeting. Of 12 simulators, each participant focused on 6 cardiac (small vessel anastomosis, aortic cannulation, cardiopulmonary bypass, aortic valve replacement, mitral valve repair, and aortic root replacement) or 6 thoracic surgical simulators (hilar dissection, esophageal anastomosis, rigid bronchoscopy, video-assisted thoracoscopic surgery lobectomy, tracheal resection, and sleeve resection). The participants provided critical feedback regarding the realism and utility of the simulators, which served as the basis for a composite assessment of the simulators. RESULTS: All participants acknowledged that simulation may not provide a wholly immersive experience. For small vessel anastomosis, the portable chest model is less realistic compared with the porcine model, but is valuable in teaching anastomosis mechanics. The aortic cannulation model allows multiple cannulations and can serve as a thoracic aortic surgery model. The cardiopulmonary bypass simulator provides crisis management experience. The porcine aortic valve replacement, mitral valve annuloplasty, and aortic root models are realistic and permit standardized training. The hilar dissection model is subject to variability of porcine anatomy and fragility of the vascular structures. The realistic esophageal anastomosis simulator presents various approaches to esophageal anastomosis. The exercise associated with the rigid bronchoscopy model is brief, and adding additional procedures should be considered. The tracheal resection, sleeve resection, and video-assisted thoracoscopic surgery lobectomy models are highly realistic and simulate advanced maneuvers. CONCLUSIONS: By providing the necessary tools, such as task trainers and assessment instruments, the Senior Tour may be one means to enhance simulation-based learning in cardiothoracic surgery. The Senior Tour members can provide regular programmatic evaluation and critical analyses to ensure that proposed simulators are of educational value

Complete genome sequence of Polynucleobacter necessarius subsp. asymbioticus type strain (QLW-P1DMWA-1T)

Polynucleobacter necessarius subsp. asymbioticus strain QLW-P1DMWA-1T is a planktonic freshwater bacterium affiliated with the family Burkholderiaceae (class Betaproteobacteria). This strain is of interest because it represents a subspecies with cosmopolitan and ubiquitous distribution in standing freshwater systems. The 16S-23S ITS genotype represented by the sequenced strain comprised on average more than 10% of bacterioplankton in its home habitat. While all strains of the subspecies P. necessarius asymbioticus are free-living freshwater bacteria, strains belonging to the only other subspecies, P. necessarius subsp. necessarius are obligate endosymbionts of the ciliate Euplotes aediculatus. The two subspecies of P. necessarius are the instances of two closely related subspecies that differ in their lifestyle (free-living vs. obligate endosymbiont), and they are the only members of the genus Polynucleobacter with completely sequenced genomes. Here we describe the features of P. necessarius subsp. asymbioticus, together with the complete genome sequence and annotation. The 2,159,490 bp long chromosome with a total of 2,088 protein-coding and 48 RNA genes is the first completed genome sequence of the genus Polynucleobacter to be published and was sequenced as part of the DOE Joint Genome Institute Community Sequencing Program 2006

Combinatorial Polymer Electrospun Matrices Promote Physiologically-Relevant Cardiomyogenic Stem Cell Differentiation

Myocardial infarction results in extensive cardiomyocyte death which can lead to fatal arrhythmias or congestive heart failure. Delivery of stem cells to repopulate damaged cardiac tissue may be an attractive and innovative solution for repairing the damaged heart. Instructive polymer scaffolds with a wide range of properties have been used extensively to direct the differentiation of stem cells. In this study, we have optimized the chemical and mechanical properties of an electrospun polymer mesh for directed differentiation of embryonic stem cells (ESCs) towards a cardiomyogenic lineage. A combinatorial polymer library was prepared by copolymerizing three distinct subunits at varying molar ratios to tune the physicochemical properties of the resulting polymer: hydrophilic polyethylene glycol (PEG), hydrophobic poly(ε-caprolactone) (PCL), and negatively-charged, carboxylated PCL (CPCL). Murine ESCs were cultured on electrospun polymeric scaffolds and their differentiation to cardiomyocytes was assessed through measurements of viability, intracellular reactive oxygen species (ROS), α-myosin heavy chain expression (α-MHC), and intracellular Ca2+ signaling dynamics. Interestingly, ESCs on the most compliant substrate, 4%PEG-86%PCL-10%CPCL, exhibited the highest α-MHC expression as well as the most mature Ca2+ signaling dynamics. To investigate the role of scaffold modulus in ESC differentiation, the scaffold fiber density was reduced by altering the electrospinning parameters. The reduced modulus was found to enhance α-MHC gene expression, and promote maturation of myocyte Ca2+ handling. These data indicate that ESC-derived cardiomyocyte differentiation and maturation can be promoted by tuning the mechanical and chemical properties of polymer scaffold via copolymerization and electrospinning techniques

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Use of Biomarkers in the Evaluation and Treatment of Hypertensive Patients

The current definition of hypertension is based on blood pressure values, and blood pressure also drives treatment decisions, is the most important treatment monitoring tool and helps estimating risk of hypertension related organ damage. In an era of precision medicine additional biomarkers are needed in the diagnosis and management of patients with hypertension. In this review we outline the areas in which functional, imaging and circulating biomarkers could help in a more individualised definition of hypertension and associated risk. We will cover biomarkers for diagnosis; of pathophysiology and prediction of hypertension; response to treatment, organ damage; and to monitor treatment. A clear focus is on the vasculature, the heart and the kidneys, whereas we see a need to further develop biomarkers of cerebral function in order to diagnose cognition deficits and monitor changes in cognition in the future to support addressing the growing burden of hypertension associated vascular dementia

Brain Protection during Cardiac Surgery: Circa 2012

Brain injury during cardiac surgery can cause a potentially disabling syndrome consisting mainly of cognitive dysfunction but can manifest itself as symptoms and signs indistinguishable from frank stroke. The cause of the damage is mainly the result of emboli consisting of solid material such as clots or atherosclerotic plaque, fat, and/or gas. These emboli enter the cerebral circulation from the cardiopulmonary bypass machine, break off the aorta during manipulation, and enter the circulation from cardiac chambers. This damage can be prevented or at least minimized by avoiding aortic manipulation, filtering aortic inflow from the pump, preventing air from entering the pump plus careful deairing of the heart. Shed blood from the cardiotomy suction should be processed by a cell saver whenever possible. By doing these maneuvers, inflammation of the brain can be avoided. Long-term neurocognitive damage has been largely prevented in large series of patients having high-risk surgery, which makes these preventive measures worthwhile