Accommodating space, time and randomness in network simulation

Interest in the possibility of dynamically simulating complex cellular processes has escalated markedly in recent years. This interest has been fuelled by three factors: the generally accepted value in understanding living processes as integrated systems; the dramatic increase in computational capability; and the availability of new or improved technology for making the quantitative measurements that are needed to drive and validate cellular simulations. Between the extremes of atom-scale and organism-scale simulation is a vast middle-ground requiring simulation strategies that are capable of dealing with a range of spatial, temporal and molecular abundance scales that are crucial for a comprehensive understanding of integrative cell biology. Although at an early stage, methodological improvements and the development of computational platforms provide some hope that simulations will emerge that can bridge the gap between network models and the true operation of the cell as a complex machine

The United Kingdom and Ireland experience of the Haemodialysis Reliable Outflow graft for vascular access

Objectives: To describe the UK and Ireland experience of the Haemodialysis Reliable Outflow graft in complex vascular access. Design: Observational, multi-centre case series. Methods: Data from any patient undergoing Haemodialysis Reliable Outflow graft were collected from eight UK and one Irish centre. Any Haemodialysis Reliable Outflow procedure between July 2013 and May 2016 was included. Demographics, primary and secondary patency rates, and complications were analysed. Results: A total of 52 patients underwent Haemodialysis Reliable Outflow graft insertion. Median age was 55 (20–86) years, 24 (46%) were male and 66% were Caucasian. Median follow-up was 290 (10–966) days and patient survival was 41/52 (79%). In total, 48 procedures were in the upper limb with 39 using the brachial artery as inflow (75%). The internal jugular vein and subclavian vein were most frequently used as access for outflow insertion. Primary patency rates at 6, 12, and 24 months were 51.2% (95% confidence interval, 38.8%–67.4%), 40.9% (95% confidence interval, 28.7%–58.2%), and 33.4% (95% confidence interval, 21.3%–52.5%), respectively. Secondary patency rates at 6, 12, and 24 months were 84.8% (95% confidence interval, 75%–95.9%), 76.5% (95% confidence interval, 64.5%–90.6%), and 70.6% (95% confidence interval, 56%–88.9%), respectively. There were 65 surgical and 49 radiological interventions resulting in 2.30 interventions per year to retain patency. Complications included four infections and two episodes of steal syndrome. Conclusion: The Haemodialysis Reliable Outflow graft provides acceptable 12-month secondary patency rates and acceptable complication rates in a UK and Ireland multi-centre series of complex access patients. Haemodialysis Reliable Outflow should be considered in patients with central pathology as a potential alternative to lower limb grafts and long-term central venous catheters.</p