Surgical simulation is an exciting area of surgical education. The future is bright as advancements in computing and graphical capabilities offer new innovations in simulator technology. Simulators must continue to undergo rigorous validation studies to ensure that time spent by trainees on bench trainers and virtual reality simulators will translate into improved surgical skills in the operating room.

Purpose: A previous study showed decreased uropathogen adherence using a novel anti-fouling coating consisting of mussel adhesive protein mimics conjugated to poly(ethylene glycol). We assessed the ability of methoxy polyethylene glycol-dihydroxyphenylalanine (Nerites Corp. Ltd., Madison, Wisconsin) coated ureteral stents to resist bacterial adherence, infection development and encrustation in a rabbit model of uropathogenic Escherichia coli cystitis. Materials and Methods:Sof-Flex® stent curls that were uncoated and coated with 3 coatings, including Surphys™ 002, 008 and 009, respectively, and uncoated Percuflex Plus® stents were inserted transurethrally into the bladder of 50 male New Zealand White rabbits (Charles River Laboratories, Montreal, Quebec, Canada), followed by instillation of uropathogenic E. coli strain GR12 (10 7 cfu). Urine was examined for bacteria on days 0, 1, 3 and 7, and for cytokine levels on day 7. On day 7 the animals were sacrificed. Stent curls and bladders were harvested for analysis. In a parallel experiment stents were challenged in vitro for 7 days with GR12 in human urine.Results: Surphys 009 coated devices showed decreased urine and stent bacterial counts compared to those in controls. Eight of 10 rabbits in the Surphys 009 group had sterile urine by day 3 vs 1 in each control group (p = 0.013), while stent adherent organisms were decreased by more than 75%. While no statistical differences were found in encrustation and bladder inflammation across the groups, immune scoring was lowest in the uncoated Sof-Flex control and Surphys 009 groups (p = 0.030). Conclusions:Surphys 009 strongly resisted bacterial attachment, resulting in improved infection clearance over that of uncoated devices. However, this did not translate to decreased encrustation, which appeared to be independent of infection in this model. Keywordsureter; stents; rabbits; Escherichia coli; dihydroxyphenylalanine BACTERIAL attachment and biofilm formation are serious problems associated with urinary stents and catheters since they lead to chronic infections that cannot be resolved without device Copyright © 2009 Despite numerous strategies to prevent these events, including anti-fouling and antimicrobial coatings, dietary and urinary modification, and oral antibiotics, nothing has yet proved efficacious. [3][4][5][6] The urinary tract has multiple strategies for dealing with invading microorganisms but the presence of a foreign device provides a novel nonhost surface to which they can attach and form a biofilm. This is supported by studies highlighting the ability of normally nonuropathogenic microorganisms to readily cause device associated UTIs. [7][8][9] Recently we performed an in vitro study using surfaces coated with PEG conjugated to a synthetic mimic of MAPs. 10 MAP mimics consisted of tripeptides of DOPA, the key adhesive component in MAPs. These peptides served as anchors and were coupled to the terminus of a 5,000 Da mPEG-DOPA 3 . Coated surfaces inhibited attachment by greater than 94% for 7 ...

Proteins that inhibit the growth and aggregation of calcium oxalate crystals play important roles in the prevention of kidney stone disease. One such protein is osteopontin (OPN), which inhibits the formation of calcium oxalate monohydrate (COM) in a phosphorylation-dependent manner. To determine the role of phosphate groups in the inhibition of COM growth by OPN, we used scanning confocal interference microscopy to compare the effects of highly phosphorylated OPN from cow milk, less phosphorylated OPN from rat bone, and nonphosphorylated recombinant OPN. COM growth was measured in the principal crystallographic directions <001>, <010>, and <100>, representing lattice-ion addition to {121}, {010}, and {100} faces, respectively. While the shapes of growth curves were very consistent from crystal to crystal, absolute growth rates varied widely. To control for this, results were expressed as changes in the aspect ratios <010>/<001> and <100>/<001>. Compared to control, bone OPN increased <010>/<001> and had no effect on <100>/<001>; milk OPN had no effect on <010>/<001>and decreased <100>/<001>; recombinant OPN had no significant effect on either aspect ratio. These findings indicate that milk OPN interacts with COM crystal faces in order of preference {100} > {121} approximately {010}, whereas bone OPN interacts in order of preference {100} approximately {121} > {010}. As {100} is the most Ca(2+)-rich face of COM, while {010} is the least Ca(2+)-rich, it appears that the OPN-mediated inhibition of COM growth occurs through a nonspecific electrostatic interaction between Ca(2+) ions of the crystal and phosphate groups of the protein.

Antibiotic use with control stents resulted in bacterial antibiotic resistance, which was not the case with the triclosan-eluting stents. Although triclosan-eluting stents did not show a clinical benefit in terms of urine and stent cultures or overall subject symptoms compared with controls, their use did result in decreased antibiotic usage and significantly fewer symptomatic infections. The triclosan-eluting stent alone is not sufficient to reduce device-associated infections in this difficult patient population.