Effects of temperature and fluid media on the scroll width size of the Descemet’s membrane endothelial keratoplasty (DMEK) donor graft

Ellen H Koo,1 Allen O Eghrari,2 Ryan S Meshkin,2 Wei Shi,1 William J Feuer,1 Karen G DeMarco,3 Arthur C Kurz3 1Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, 2Wilmer Eye Institute, Johns Hopkins University School of Medicine, 3KeraLink International, Baltimore, MD, USA Aim: Our study was conducted to evaluate whether higher temperature leads to increased – or wider – scroll widths of the Descemet’s membrane endothelial keratoplasty (DMEK) donor graft.Purpose: To investigate the effects of temperature and fluid media on the DMEK donor graft scroll widths.Materials and methods: This research work was a laboratory investigation. Baseline cell count was taken via specular microscopy for the donor corneas at room temperature (20°C–25°C). The endothelium sides of the donor corneas were stained with Trypan Blue Solution 0.4% for 30 s, and the Descemet’s membranes were stripped. The DMEK donor grafts were placed into three different fluid media – Optisol®, Balanced Salt Solution (BSS), and BSS PLUS® (BSS Plus). The DMEK donor grafts were then transferred into cold temperature (4°C) for 60 min, after which the donor grafts’ scroll widths were examined and measured. The donor grafts were then warmed in the incubator and brought to physiological temperature (35°C–37°C), and their scroll widths were examined and measured again.Results: In 30 measurements of ten tissues across three temperature and fluid conditions, the average scroll width measured 1.73 mm, ranging from 1.1 to 2.9 mm. In a mixed linear model, the scroll widths increased with temperature (P=0.02). There was no significant difference in scroll widths among the three solutions (P=0.84, mixed linear model).Conclusion: We observed an increase in DMEK donor graft scroll widths with higher temperatures. The usage of BSS Plus as media solution could also lead to smaller DMEK donor graft scroll widths, compared with BSS, but our study does not establish this. Keywords: DMEK, graft scroll, graft conformation, DMEK scroll, DMEK graft&nbsp

Toward Community Standards and Software for Whole-Cell Modeling

OBJECTIVE: Whole-cell (WC) modeling is a promising tool for biological research, bioengineering, and medicine. However, substantial work remains to create accurate comprehensive models of complex cells. METHODS: We organized the 2015 Whole-Cell Modeling Summer School to teach WC modeling and evaluate the need for new WC modeling standards and software by recoding a recently published WC model in the Systems Biology Markup Language. RESULTS: Our analysis revealed several challenges to representing WC models using the current standards. CONCLUSION: We, therefore, propose several new WC modeling standards, software, and databases. SIGNIFICANCE: We anticipate that these new standards and software will enable more comprehensive models