30 research outputs found
Discussion: Clinical Application of a Patient-Specific, Three-Dimensional Printing Guide Based on Computer Simulation for Rhinoplasty
No full textIslet Assessment for Transplantation
No full textAuthor Manuscript: 2010 December 1.Purpose of review:
There is a critical need for meaningful viability and potency assays that characterize islet preparations for release prior to clinical islet cell transplantation (ICT). Development, testing, and validation of such assays have been the subject of intense investigation for the past decade. These efforts are reviewed, highlighting the most recent results while focusing on the most promising assays.
Recent Findings:
Assays based on membrane integrity do not reflect true viability when applied to either intact islets or dispersed islet cells. Assays requiring disaggregation of intact islets into individual cells for assessment introduce additional problems of cell damage and loss. Assays evaluating mitochondrial function, specifically mitochondrial membrane potential, bioenergetic status, and cellular oxygen consumption rate (OCR), especially when conducted with intact islets, appear most promising in evaluating their quality prior to ICT. Prospective, quantitative assays based on measurements of OCR with intact islets have been developed, validated and their results correlated with transplant outcomes in the diabetic nude mouse bioassay.
Conclusion:
More sensitive and reliable islet viability and potency tests have been recently developed and tested. Those evaluating mitochondrial function are most promising, correlate with transplant outcomes in mice, and are currently being evaluated in the clinical setting.National Center for Research Resources (U.S.) (Grant)National Institutes of Health (U.S.) (Grant U42 RR 016598–01)National Institutes of Health (U.S.) (Grant RO1-DK063108–01A1)Iacocca FoundationSchott FoundationCarol Olson Memorial Diabetes Research Fun
Oxygenation of the Intraportally Transplanted Pancreatic Islet
No full textIntraportal islet transplantation (IT) is not widely utilized as a treatment for type 1 diabetes. Oxygenation of the intraportally transplanted islet has not been studied extensively. We present a diffusion-reaction model that predicts the presence of an anoxic core and a larger partly functional core within intraportally transplanted islets. Four variables were studied: islet diameter, islet fractional viability, external oxygen partial pressure (P) (in surrounding portal blood), and presence or absence of a thrombus on the islet surface. Results indicate that an islet with average size and fractional viability exhibits an anoxic volume fraction (AVF) of 14% and a function loss of 72% at a low external P. Thrombus formation increased AVF to 30% and function loss to 92%, suggesting that the effect of thrombosis may be substantial. External P and islet diameter accounted for the greatest overall impact on AVF and loss of function. At our institutions, large human alloislets (>200 μm diameter) account for ~20% of total islet number but ~70% of total islet volume; since most of the total transplanted islet volume is accounted for by large islets, most of the intraportal islet cells are likely to be anoxic and not fully functional
Consecutive Bilateral Breast Reconstruction Using Stacked Abdominally Based and Posterior Thigh Free Flaps
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Discussion: Breast Reconstruction Using a Three-Dimensional Absorbable Mesh Scaffold and Autologous Fat Grafting: A Composite Strategy Based on Tissue-Engineering Principles
No full textMultiflap Autologous Breast Reconstruction with Use of a Thigh Perforator Flap Can Be Considered Large-Volume Vascularized Fat Grafting
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