Publications by authors named "Gregory McKenna"

Introduction: Normothermic regional perfusion (NRP) represents an innovative technology that improves the outcomes for liver and kidney recipients of donation after circulatory determination of death (DCD) organs but protocols for abdominal-only NRP (A-NRP) DCD are lacking in the US.

Methods: We describe the implementation and expansion strategies of a transplant-center-based A-NRP DCD program that has grown in volume, geographical reach, and donor acceptance parameters, presented as four eras.

Results: In the implementation era, two donors were attempted, and one liver graft was transplanted.

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Article Synopsis
  • - Donation after circulatory death (DCD) donors make up over 30% of organ donors in the U.S., but they result in fewer successful organ transplants compared to donation after brain death.
  • - A cost comparison study showed that acquiring livers from DCD donors costs $15,029 more per transplant than from brain death donors, with 18% of DCD costs linked to unsuccessful donation attempts (dry runs).
  • - To enhance the efficiency of DCD liver acquisition and maintain the gains in the donor pool, strategies like local recovery and better organ assessments before retrieval need to be implemented to reduce costs associated with dry runs.
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There is a subset of patients with lower MELD scores who are at substantial risk of waitlist mortality. In order to transplant such patients, transplant centers must utilize "nonstandard" donors (eg, living donors, donation after circulatory death), which are traditionally offered to those patients who are not at the top of the waitlist. We used Organ Procurement and Transplantation data to evaluate center-level and region-level variability in the utilization of nonstandard donors and its impact on MELD at transplant among adult liver-alone non-status 1 patients transplanted from April 1, 2020, to September 30, 2022.

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Standard US practice for donation after circulatory death (DCD) abdominal organ procurement is superrapid recovery (SRR). A newer approach using thoracoabdominal normothermic regional perfusion (TA-NRP) shows promise for better recipient outcomes for all organs, but there are few reports of abdominal recipient outcomes from TA-NRP donors. We used the United Network for Organ Sharing data to identify all cardiac DCD donors from October 1, 2020, to May 20, 2022, and categorized them by recovery procedure (SRR vs TA-NRP).

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Ultra-stable fluoropolymer glasses were created using vacuum pyrolysis deposition that show large fictive temperature T reductions relative to the glass transition temperature T of the rejuvenated material. T was also found to be 11.4 K below the dynamic VFT temperature T.

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Accurate assessment of donor quality at the time of organ offer for liver transplantation candidates may be inadequately captured by the donor risk index (DRI). We sought to develop and validate a novel objective and simple model to assess donor risk using donor level variables available at the time of organ offer. We utilized national data from candidates undergoing primary LT (2013-2019) and assessed the prediction of graft failure 1 year after LT.

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Liver transplantation rates have been negatively affected by the pandemic caused by coronavirus disease 2019 (COVID-19), the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Current practice in the liver transplant community is to avoid utilizing SARS-CoV-2-positive donors for liver transplantation unless there is a compelling reason such as recipient illness severity. In this case, we report the use of a donor who had a positive exposure to and symptom history for COVID-19 and tested positive for SARS-CoV-2 on admission for a liver transplant recipient with primary sclerosing cholangitis and a Model of End-Stage Liver Disease score of 23 with no known COVID-19 exposures.

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Importance: Acuity circles (AC) liver allocation policy was implemented to eliminate donor service area geographic boundaries from liver allocation and to decrease variability in median Model of End-stage Liver Disease (MELD) score at transplant and wait list mortality. However, the broader sharing of organs was also associated with more flights for organ procurements and higher costs associated with the increase in flights.

Objective: To determine whether the costs associated with liver acquisition changed after the implementation of AC allocation.

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The dynamics of a series of soft colloids comprised of polystyrene cores with poly(N-isopropylacrylamide) (PNIPAM) coronas was investigated by diffusing wave spectroscopy (DWS). The modulus of the coronas was varied by changing the cross-link density and we were able to interpret the results within a hard-soft mapping framework. The soft, swellable particle properties were modeled using an extended Flory-Rehner theory and a Hertzian pair potential.

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The glass transition temperature () of a binary miscible mixture of molecular glasses, termed a coamorphous glass, is often synergistically increased over that expected for an athermal mixture due to the strong interactions between the two components. This synergistic interaction is particularly important for the formulation of coamorphous pharmaceuticals since the molecular interactions and resulting strongly impact stability against crystallization, dissolution kinetics, and bioavailability. Current models that describe the composition dependence of for binary systems, including the Gordon-Taylor, Fox, Kwei, and Braun-Kovacs equations, fail to describe the behavior of coamorphous pharmaceuticals using parameters consistent with experimental Δ and Δα.

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Crystallization of active pharmaceutical ingredients (APIs) from the supercooled liquid state is an important issue in determining the stability of amorphous pharmaceutical dispersions. In the present study, the isothermal crystallization from the supercooled liquid state of the pharmaceutical compound nifedipine was investigated by both rheological and differential scanning calorimetry (DSC) measurements, and the crystallization kinetics was fitted to the Johnson-Mehl-Avrami (JMA) equation. Both the crystallization induction time and completion time from the two methods were used to construct the time-temperature-transformation (TTT) diagram for nifedipine.

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Non-contrast pelvic computed tomography (CT) can detect severe iliac artery calcifications that present technical contraindications to kidney transplantation (TCT). We screened 454 asymptomatic patients with a history of any of the following: hemodialysis >10 years, diabetes mellitus >20 years, coronary artery disease (CAD) with percutaneous or surgical interventions, carotid disease, diabetes with below-/above-knee amputations, and heart-kidney transplantation candidacy. Patients with normal dorsalis pedis and/or tibialis posterior pulses were not screened.

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Objective: Limited data are available on the outcome of infants born after uterus transplantation. Our aim was to describe the hospital course and laboratory findings in the first 2 months of life of the 12 infants born in the Dallas UtErus Transplant Study (DUETS).

Study Design: Based on the trial protocol, information about infants was collected in a prospective fashion, including infant demographics, hospital course, and laboratory values.

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Mechanical spectral hole burning (MSHB) has been used to investigate the nonlinear dynamics in polymers, ranging from melts, solutions, block co-polymers, and glasses. MSHB was developed as an analog to the dielectric spectral hole burning method, which is not readily applicable in polymers due to weak dielectric response. While similar holes were observed in both mechanical and dielectric hole burning, the interpretations were different.

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Although post-kidney transplant (KT) wound complications are associated with elevated body mass index (BMI), BMI is not an accurate surrogate of obesity. On the other hand, subcutaneous depth (SQD) measurement is a direct marker of truncal obesity. We examined outcomes of differing intraoperative SQD measurements in 113 KT-only recipients over 20 months.

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Objective: To describe aggregated pregnancy outcomes after uterus transplantation from a single, experienced center.

Methods: This prospective study reports on live births among 20 women who received a uterus transplant from 2016 to 2019 at Baylor University Medical Center at Dallas. These live births occurred between November 2017 and September 2020.

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Cold crystallization of amorphous pharmaceuticals is an important aspect in the search to stabilize amorphous or glassy compounds used as amorphous pharmaceutical ingredients (APIs). In the present work, we report results for the isothermal crystallization of the compound GDC-0276 based on differential scanning calorimetric and rheometric measurements. The kinetics of isothermal crystallization from the induction time to the completion of crystallization can be described by the classic Johnson-Mehl-Avrami (JMA) equation.

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Despite decades of exploration of the colloidal glass transition, mechanistic explanation of glassy relaxation processes has remained murky. State-of-the-art theoretical models of the colloidal glass transition such as random first order transition theory, active barrier hopping theory, and non-equilibrium self-consistent generalized Langevin theory assert that relaxation reported at volume fractions above the ideal mode coupling theory prediction φg,MCT requires some sort of activated process, and that cooperative motion plays a central role. However, discrepancies between predicted and measured values of φg and ambiguity in the role of cooperative dynamics persist.

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Purpose: To evaluate the effect of routine administration of post-procedural antibiotics following elective uterine artery embolization (UAE) on infectious complication rates.

Materials And Methods: The charts of patients who underwent UAE between January 2013 and September 2019 were retrospectively reviewed. Prior to January 15, 2016, all patients received post-procedural antibiotics with 500 mg of ciprofloxacin twice a day orally for 5 days.

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When coupled with the generalized Stokes-Einstein (GSE) equation, it is often reported that micro-rheology probes the dynamic properties differently than do macroscopic rheological measurements, especially in relatively condensed systems. In the present work, we empirically examine the GSE in its widely used form: following an analytical continuation, the Fourier transformed particle mean-square displacement (MSD) is used to determine the dynamic moduli [G'(ω) and G''(ω)] and we compare the results with those obtained by direct inverse Laplace transform calculation of the relevant viscoelastic functions (either relaxation modulus or creep compliance) from the MSD. The results show that the inverse Laplace approaches can differ from the Fourier approach and give better agreement with macroscopic rheological measurements when this is the case.

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Background: Uterus transplantation is a treatment for absolute uterine infertility and can be performed with living and deceased donors. Given the safety and increased utilization of robotic assistance with other gynecologic and transplant donor operations, we adopted a robot-assisted approach to donor hysterectomy. This study compared early outcomes and morbidity of the robot-assisted approach to donor hysterectomy with the traditionally performed open approach and addressed whether the robot-assisted approach is safe and offers advantages for the donor.

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