Sommer E. Gentry

Bio: Sommer E. Gentry is an academic researcher from United States Naval Academy. The author has contributed to research in topics: Transplantation & Liver transplantation. The author has an hindex of 26, co-authored 90 publications receiving 2933 citations. Previous affiliations of Sommer E. Gentry include Johns Hopkins University School of Medicine & University of Pittsburgh.

Kidney Paired Donation and Optimizing the Use of Live Donor Organs

Abstract: ContextBlood type and crossmatch incompatibility will exclude at least one third of patients in need from receiving a live donor kidney transplant. Kidney paired donation (KPD) offers incompatible donor/recipient pairs the opportunity to match for compatible transplants. Despite its increasing popularity, very few transplants have resulted from KPD.ObjectiveTo determine the potential impact of improved matching schemes on the number and quality of transplants achievable with KPD.Design, Setting, and PopulationWe developed a model that simulates pools of incompatible donor/recipient pairs. We designed a mathematically verifiable optimized matching algorithm and compared it with the scheme currently used in some centers and regions. Simulated patients from the general community with characteristics drawn from distributions describing end-stage renal disease patients eligible for renal transplantation and their willing and eligible live donors.Main Outcome MeasuresNumber of kidneys matched, HLA mismatch of matched kidneys, and number of grafts surviving 5 years after transplantation.ResultsA national optimized matching algorithm would result in more transplants (47.7% vs 42.0%, P<.001), better HLA concordance (3.0 vs 4.5 mismatched antigens; P<.001), more grafts surviving at 5 years (34.9% vs 28.7%; P<.001), and a reduction in the number of pairs required to travel (2.9% vs 18.4%; P<.001) when compared with an extension of the currently used first-accept scheme to a national level. Furthermore, highly sensitized patients would benefit 6-fold from a national optimized scheme (2.3% vs 14.1% successfully matched; P<.001). Even if only 7% of patients awaiting kidney transplantation participated in an optimized national KPD program, the health care system could save as much as $750 million.ConclusionsThe combination of a national KPD program and a mathematically optimized matching algorithm yields more matches with lower HLA disparity. Optimized matching affords patients the flexibility of customizing their matching priorities and the security of knowing that the greatest number of high-quality matches will be found and distributed equitably.

The Interplay of Socioeconomic Status, Distance to Center, and Interdonor Service Area Travel on Kidney Transplant Access and Outcomes

Abstract: Background and objectives: Variation in kidney transplant access across the United States may motivate relocation of patients with ability to travel to better-supplied areas. Design, setting, participants, & measurements: We examined national transplant registry and U.S. Census data for kidney transplant candidates listed in 1999 to 2009 with a reported residential zip code (n = 203,267). Cox's regression was used to assess associations of socioeconomic status (SES), distance from residence to transplant center, and relocation to a different donation service area (DSA) with transplant access and outcomes. Results: Patients in the highest SES quartile had increased access to transplant compared with those with lowest SES, driven strongly by 76% higher likelihood of living donor transplantation (adjusted hazard ratio [aHR] 1.76, 95% confidence interval [CI] 1.70 to 1.83). Waitlist death was reduced in high compared with low SES candidates (aHR 0.86, 95% CI 0.84 to 0.89). High SES patients also experienced lower mortality after living and deceased donor transplant. Patients living farther from the transplant center had reduced access to deceased donor transplant and increased risk of post-transplant death. Inter-DSA travel was associated with a dramatic increase in deceased donor transplant access (HR 1.94, 95% CI 1.88 to 2.00) and was predicted by high SES, white race, and longer deceased-donor allograft waiting time in initial DSA. Conclusions: Ongoing disparities exist in kidney transplantation access and outcomes on the basis of geography and SES despite near-universal insurance coverage under Medicare. Inter-DSA travel improves access and is more common among high SES candidates.

Generalizing motion edits with Gaussian processes

Abstract: One way that artists create compelling character animations is by manipulating details of a character's motion. This process is expensive and repetitive. We show that we can make such motion editing more efficient by generalizing the edits an animator makes on short sequences of motion to other sequences. Our method predicts frames for the motion using Gaussian process models of kinematics and dynamics. These estimates are combined with probabilistic inference. Our method can be used to propagate edits from examples to an entire sequence for an existing character, and it can also be used to map a motion from a control character to a very different target character. The technique shows good generalization. For example, we show that an estimator, learned from a few seconds of edited example animation using our methods, generalizes well enough to edit minutes of character animation in a high-quality fashion. Learning is interactive: An animator who wants to improve the output can provide small, correcting examples and the system will produce improved estimates of motion. We make this interactive learning process efficient and natural with a fast, full-body IK system with novel features. Finally, we present data from interviews with professional character animators that indicate that generalizing and propagating animator edits can save artists significant time and work.

Desensitization in HLA-incompatible kidney recipients and survival.

Abstract: Background More than 20,000 candidates for kidney transplantation in the United States are sensitized to HLA and may have a prolonged wait for a transplant, with a reduced transplantation rate and an increased rate of death. One solution is to perform live-donor renal transplantation after the depletion of donor-specific anti-HLA antibodies. Whether such antibody depletion results in a survival benefit as compared with waiting for an HLA-compatible kidney is unknown. Methods We used a protocol that included plasmapheresis and the administration of low-dose intravenous immune globulin to desensitize 211 HLA-sensitized patients who subsequently underwent renal transplantation (treatment group). We compared rates of death between the group undergoing desensitization treatment and two carefully matched control groups of patients on a waiting list for kidney transplantation who continued to undergo dialysis (dialysis-only group) or who underwent either dialysis or HLA-compatible transplantation (dialysis-or-tr...

Racial disparities in surgical care and outcomes in the United States: a comprehensive review of patient, provider, and systemic factors.

Abstract: It is well known that there are significant racial disparities in health care outcomes, including surgery. However, the mechanisms that lead to these disparities are still not fully understood. In this comprehensive review of the currently published surgical disparity literature in the United States, we assess racial disparities in outcomes after surgical procedures, focusing on patient, provider, and systemic factors. The PubMed, EMBASE, and Cochrane Library electronic databases were searched with the keywords: healthcare disparities AND surgery AND outcome AND US. Only primary research articles published between April 1990 and December 2011 were included in the study. Studies analyzing surgical patients of all ages and assessing the endpoints of mortality, morbidity, or the likelihood of receiving surgical therapy were included. A total of 88 articles met the inclusion criteria. This evidence-based review was compiled in a systematic manner, relying on retrospective, cross-sectional, case-control, and prospective studies in the absence of Class I studies. The review found that patient factors such as insurance status and socioeconomic status (SES) need to be further explored, as studies indicated only a premature understanding of the relationship between racial disparities and SES. Provider factors such as differences in surgery rates and treatment by low volume or low quality surgeons also appear to play a role in minority outcome disparities. Finally, systemic factors such as access to care, hospital volume, and hospital patient population have been shown to contribute to disparities, with research consistently demonstrating that equal access to care mitigates outcome disparities.