Open Sequence Initiative: a part submission standard to complement modern DNA assembly techniques

The discipline of synthetic biology emphasizes the application of engineering principles such as standardization, abstraction, modularity, and rational design to complex biological systems. The archetypical example of such standardization is BioBrick RFC[10], introduced in 2003 by Tom Knight at MIT. BioBricks are stored on a standard plasmid, pSB1C3, which contains prefix and suffix sequences flanking the DNA sequence specifying a biological part. The prefix and suffix sequences contain two pairs of 6 base-pair (bp) restriction enzyme sites (EcoRI+XbaI and SpeI+PstI), which can be used for both part assembly and quality control. BioBricks are intended to be well- characterized biological parts, such as genes or promoters, that function in a predictable fashion and can be readily combined to make complex systems. The rules of the RFC[10] BioBrick assembly method require that none of the restriction sites used in the prefix and suffix be present in the parts themselves. This requirement can be an onerous imposition for iGEM teams developing large, novel parts, such as genes or entire operons that are obtained by amplifying DNA sequences from environmental samples or microorganisms. While iGEM teams may use methods such as site-directed mutagenesis to remove illegal restriction sites from a part's sequence, it is certainly possible that this mutation will alter the functionality of the part – a very undesirable outcome. In addition, the mutagenesis of illegal restriction sites is an unnecessary burden on teams, given the limited time and resources available to teams during each year’s iGEM competition. Efforts spent mutagenizing sites would be better spent characterizing and improving parts. This RFC proposes an alternative submission standard to eliminate these problems

Acute Myopericarditis Due to Human Granulocytic Anaplasmosis

We present a case of a 54-year-old gentleman with a history of hypertension and chronic HIV who presented with fever and epigastric pain, found to have elevated troponin-I levels and diffuse ST-segement elevations on ECG without clinical evidence of ischemia concerning for myopericarditis. Initial laboratory findings also included thrombocytopenia and elevated aminotransferases as well as computed tomography imaging revealing splenic infarcts. Given plausible exposure to ticks, this led to the eventual diagnosis of anaplasmosis confirmed on PCR assay. Cardiac MRI images confirmed myocardial involvement, which resolved with antibiotic treatment. While rare, cardiac involvement is possible sequelae of anaplasmosis infection as illustrated by this case

High-Risk Pulmonary Hypertension Does Not Worsen Outcomes in Heart Transplantation

Pulmonary hypertension (PH) is a relative contraindication to heart transplantation (HT). Multiple studies showed increased mortality in patients with PH. Advances in care may have led to improved outcomes in the modern era. We analyzed patients who underwent HT at our institution between 2014 and 2018. We divided patients into 2 groups based on the presence of high-risk PH defined as either pulmonary vascular resistance \u3e3 Wood units or transpulmonary gradient \u3e15 mm Hg. The primary outcome was survival. Secondary outcomes were post-HT morbidity and changes in hemodynamics. Subsequently, we analyzed national trends of single organ HT recipients with a high-risk PH between 1994 and 2018 from the United Network for Organ Sharing registry. Of 98 patients who underwent HT at our center, 32% had PH. In patients without and with PH, the survival was 100% at 30 days, 87%, and 81% at 3 years (p = 0.96). In both groups, pulmonary vascular resistance and trans-pulmonary gradient decreased after HT. Nationwide data revealed 30-day survival without and with PH at 97% and 98% (p = 0.47) and 3-year survival at 86% and 87% (p = 0.84), respectively, in 2018. The proportion of recipients with PH decreased from 25% in 1994 to 19% in 2018. Recipients of HT with and without high-risk PH had similar early and late mortality in a single-center and nationwide analysis. PH improved immediately after transplant. The United Network for Organ Sharing registry analysis demonstrates continued improvement in survival in patients with PH in the modern era, whereas the relative percentage of recipients with PH decreased over time