Browsing by Author "Yun, EJun"

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    571 Effectiveness of Compression Garments with Silicone versus Compression Garments Alone on Hypertrophic Scar
    (Oxford University Press, 2023-05-15) Robertson, Karen; Wang, David; Tran, Khoa; Yun, EJun; Stevens, Katelyn; Hartman, Brett; Surgery, School of Medicine
    Introduction: Only a few studies have looked at the effects of custom compression garments with silicone sheeting sewn into the garments versus garments alone on scar management. This retrospective study hypothesizes that garments with silicone will improve the Modified Vancouver Scar Scale (mVSS) total scores and sub-scores of pliability, vascularity and height of hypertrophic scars(HTS) when compared to garments alone. Methods: This is a retrospective study of patients that were autografted or required >21 days to heal and placed in compression garments with or without silicone between 2013 and 2020. Charts were reviewed and mVSS scores from 91 patients with 191 scar locations (134 silicone/57 non-silicone) were collected at 1,3,6,9,12 months. Descriptive statistics were used to describe the sample characteristics. The mean mVSS score and mean sub-scores for pliability, height and vascularity were computed at 1,3,6,9,12 months and reported for the silicone and non-silicone groups. Results: When comparing the two groups at 9-months (with 45% of initial scars scored), the silicone group had a greater decrease in numerical value and overall % change from 1 to 9-months as compared to the non-silicone group in all areas. The results at 12-months (with 30% of initial scars scored) demonstrated the non-silicone group had a greater decrease in numerical value and % change in height and overall score. Pliability had a 25% improvement in silicone group compared to 16% change in non-silicone group. Vascularity % change was similar with a 47% change in non-silicone group and 46% change in silicone group. The scars in silicone group that were analyzed at 12-months were consistently scored higher across prior months.  Conclusions: Silicone group demonstrated improved %change in all categories at 9-months and in pliability %change at 12-months despite the decreased sample size. Pliability is improved with the use of silicone garments. Although the 12-month %change in mean for height, vascularity and total score did not show improvement over non-silicone, this reflects the return patients having significant scarring throughout treatment and needing continued interventions. These returning patients had scars in the non-silicone group as well that were also rated resulting in the disparity in the groups. The patients in the silicone group with improved scars did not continue follow-up at 12-months. Further research with focus on 9-18 month follow-up mVSS scores is warranted. Applicability of Research to Practice: Effectiveness of adding silicone to garments in scar treatment.
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    A robust fluorescence-based assay for human erythrocyte Ca++ efflux suitable for high-throughput inhibitor screens
    (Springer, 2023) Sims, Jeremiah N.; Yun, EJun; Chu, Jonathan; Siddiqui, Mansoor A.; Desai, Sanjay A.; Surgery, School of Medicine
    Intracellular calcium is maintained at very low concentrations through the action of PMCA Ca++ extrusion pumps. Although much of our knowledge about these Ca++ extrusion pumps derives from studies with human erythrocytes, kinetic studies of Ca++ transport for these cells are limited to radioisotope flux measurements. Here, we developed a robust, microplate-based assay for erythrocyte Ca++ efflux using extracellular fluorescent Ca++ indicators. We optimized Ca++ loading with the A23187 ionophore, established conditions for removal of the ionophore, and adjusted fluorescent dye sensitivity by addition of extracellular EGTA to allow continuous tracking of Ca++ efflux. Efflux kinetics were accelerated by glucose and inhibited in a dose-dependent manner by the nonspecific inhibitor vanadate, revealing that Ca++ pump activity can be tracked in a 384-well microplate format. These studies enable radioisotope-free kinetic measurements of the Ca++ pump and should facilitate screens for specific inhibitors of this essential transport activity.
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    The archaeal Dps nanocage targets kidney proximal tubules via glomerular filtration
    (American Society for Clinical Investigation, 2019-09-03) Uchida, Masaki; Maier, Bernhard; Waghwani, Hitesh Kumar; Selivanovitch, Ekaterina; Pay, S. Louise; Avera, John; Yun, EJun; Sandoval, Ruben M.; Molitoris, Bruce A.; Zollman, Amy; Douglas, Trevor; Hato, Takashi; Medicine, School of Medicine
    Nature exploits cage-like proteins for a variety of biological purposes, from molecular packaging and cargo delivery to catalysis. These cage-like proteins are of immense importance in nanomedicine due to their propensity to self-assemble from simple identical building blocks to highly ordered architecture and the design flexibility afforded by protein engineering. However, delivery of protein nanocages to the renal tubules remains a major challenge because of the glomerular filtration barrier, which effectively excludes conventional size nanocages. Here, we show that DNA-binding protein from starved cells (Dps) — the extremely small archaeal antioxidant nanocage — is able to cross the glomerular filtration barrier and is endocytosed by the renal proximal tubules. Using a model of endotoxemia, we present an example of the way in which proximal tubule–selective Dps nanocages can limit the degree of endotoxin-induced kidney injury. This was accomplished by amplifying the endogenous antioxidant property of Dps with addition of a dinuclear manganese cluster. Dps is the first-in-class protein cage nanoparticle that can be targeted to renal proximal tubules through glomerular filtration. In addition to its therapeutic potential, chemical and genetic engineering of Dps will offer a nanoplatform to advance our understanding of the physiology and pathophysiology of glomerular filtration and tubular endocytosis.