Suppression of Richtmyer-Meshkov Instability via Special Pairs of Shocks and Phase Transitions.

The classical Richtmyer-Meshkov instability (RMI) is a hydrodynamic instability characterizing the evolution of an interface following shock loading. In contrast to other hydrodynamic instabilities such as Rayleigh-Taylor, it is known for being unconditionally unstable: regardless of the direction of shock passage, any deviations from a flat interface will be amplified. In this article, we show that for negative Atwood numbers, there exist special sequences of shocks which result in a nearly perfectly suppressed instability growth. We demonstrate this principle computationally and experimentally with stepped fliers and phase transition materials. A fascinating immediate corollary is that in specific instances, a phase-transitioning material may self-suppress RMI.

Creation and Characterization of Matter-Wave Breathers.

We report the creation of quasi-1D excited matter-wave solitons, "breathers," by quenching the strength of the interactions in a Bose-Einstein condensate with attractive interactions. We characterize the resulting breathing dynamics and quantify the effects of the aspect ratio of the confining potential, the strength of the quench, and the proximity of the 1D-3D crossover for the two-soliton breather. Furthermore, we demonstrate the complex dynamics of a three-soliton breather created by a stronger interaction quench. Our experimental results, which compare well with numerical simulations, provide a pathway for utilizing matter-wave breathers to explore quantum effects in large many-body systems.

Simulating Transplant Small-for-size Grafts Using Human Liver Monosegments: The Impact of Portal Perfusion Pressure.

Small-for-size-liver grafts (SFSG) in adult transplant recipients have elevated risk of graft failure, limiting its application in clinical liver transplantation. Relevant preclinical model of SFSG is lacking. Relevant to deceased-donor split liver transplant and living-donor liver transplant in adult recipients, in this study, we present our initial characterization of SFSG model using monosegments of a discarded human donor liver.

Antithymocyte Globulin Use for Corticosteroid Nonresponsive Rejection After Liver Transplantation.

BACKGROUND AND AIMS: Acute cellular rejection after liver transplantation usually responds to intravenous corticosteroids, yet some episodes are corticosteroid-nonresponsive. We report our experience using antithymocyte globulin therapy for corticosteroid-nonresponsive acute cellular rejection in liver transplant recipients. METHODS: From January 1, 2002 to January 1, 2010, 1436 patients underwent 1548 liver or liver with other organ transplantations at our institution. We identified all patients treated with antithymocyte globulin during this timeframe for corticosteroid-nonresponsive rejection. RESULTS: Twenty patients required antithymocyte globulin for 21 episodes of corticosteroid-nonresponsive rejection. Antithymocyte globulin was started a median (range) of 27 (7-2434) days post-transplantation, and median total antithymocyte globulin dose and duration was 10.5 (7.5-26.25) mg/kg and 7 (5-13) days, respectively. Resolution or marked histological improvement of rejection on Day 7 liver allograft biopsies occurred in 90% of rejection episodes treated with antithymocyte globulin. Three-year graft and patient survival rates were 60% and 65%, respectively, compared with 79% and 84% in patients not requiring antithymocyte globulin. CONCLUSIONS: Antithymocyte globulin was an effective therapy for corticosteroid-nonresponsive rejection, with excellent short-term outcomes. Some liver transplant recipients failed to respond, and long-term survival was reduced, even in those who responded to antithymocyte globulin.

Allograft Portacaval Shunt in Small-for-Size Liver in Deceased Donor Liver Transplant.

Portal hyperperfusion is detrimental to small-for-size livers (SFSLs) in liver transplantation. Surgical techniques modulating portal inflow provide the most effective approach to protect the SFSL. In this report, we describe a technique creating an allograft portacaval shunt that effectively attenuates portal inflow without a requirement of extensive surgical dissection in the recipient during the transplantation.

Incidence and Outcome of Small-for-Size Liver Grafts Transplanted in Adult Recipients.

Small-for-size liver transplantation (SFS-LT) carries high morbidity and mortality after transplantation. SFS-LT is usually associated with living-donor or deceased-donor split LT; however its incidence and outcome are poorly defined in adult LT recipients who receive whole grafts (WLT). In this study, we retrospectively reviewed our cohort of 3,106 deceased-donor LT in adult recipients. We found that among the 31 split LTs, 11 (35.5%) were SFS. In contrast, there only 1.08% of the whole-graft transplants (31 out of 2,868) were SFS. Although less common, SFS-WLT is associated with poorer long-term outcome of both graft and patient survivals.

Waitlist Outcomes for Patients Relisted Following Failed Donation After Cardiac Death Liver Transplant: Implications for Awarding Model for End-Stage Liver Disease Exception Scores.

Understanding of outcomes for patients relisted for ischemic cholangiopathy following a donation after cardiac death (DCD) liver transplant (LT) will help standardization of a Model for End-Stage Liver Disease exception scheme for retransplantation. Early relisting (E-RL) for DCD graft failure caused by primary nonfunction (PNF) or hepatic artery thrombosis (HAT) was defined as relisting ≤14 days after DCD LT, and late relisting (L-RL) due to biliary complications was defined as relisting 14 days to 3 years after DCD LT. Of 3908 DCD LTs performed nationally between 2002 and 2016, 540 (13.8%) patients were relisted within 3 years of transplant (168 [4.3%] in the E-RL group, 372 [9.5%] in the L-RL group). The E-RL and L-RL groups had waitlist mortality rates of 15.4% and 10.5%, respectively, at 3 mo and 16.1% and 14.3%, respectively, at 1 year. Waitlist mortality in the L-RL group was higher than mortality and delisted rates for patients with exception points for both hepatocellular carcinoma (HCC) and hepatopulmonary syndrome (HPS) at 3- to 12-mo time points (p < 0.001). Waitlist outcomes differed in patients with early DCD graft failure caused by PNF or HAT compared with those with late DCD graft failure attributed to biliary complications. In L-RL, higher rates of waitlist mortality were noted compared with patients listed with exception points for HCC or HPS.

Choice of Partial Splenic Embolization Technique in Liver Transplant Recipients Correlates With Risk of Infectious Complications.

BACKGROUND: Complications of cirrhosis may persist after liver transplantation. When indicated, partial splenic embolization (PSE) is an alternative to splenectomy but can cause severe infection. The identification of modifiable risk factors when performing PSE in immunocompromised liver transplant recipients may help reduce the risk of severe infection. METHODS: Data were collected retrospectively for all PSE performed after liver transplantation at a single institution and included demographics, etiology of liver disease, indication for PSE, vaccination status, laboratory findings, procedural details, extent and pattern of splenic infarction, hospital length-of-stay, readmissions, procedural complications, and mortality. Statistical analysis included 2-tailed t test, Fisher exact test, and Kaplan-Meier survival curves, with significance defined as P < .05. RESULTS: Sixteen patients received 22 embolizations, with 11 patients undergoing a single session and 5 patients undergoing multiple sessions. Indications included hypersplenism, gastrointestinal hemorrhage, ascites, and autoimmune hemolytic anemia. PSE produced significant and sustained cell count increases, improved ascites, and controlled hemorrhage. Splenic abscess, septic shock, need for splenectomy, and PSE-related mortality were seen in the group with large confluent splenic infarction but not in peripheral/wedge-shaped infarction. Multiple-session PSE exclusively using particles for embolization correlated with the pattern of peripheral/wedge-shaped infarction and avoided severe infection and PSE-related mortality. CONCLUSIONS: PSE in the immunosuppressed liver transplant recipient is an effective alternative to splenectomy, but carries substantial infectious risk. The risk is decreased when PSE performed with polyvinyl alcohol particles results in a pattern of peripheral/wedge-shaped infarction, which correlates with smaller infarction volumes, favorable length-of-stay, and minimal risk of abscess, sepsis, and mortality.

Practical uncertainty reduction and quantification in shock physics measurements.

We report the development of a simple error analysis sampling method for identifying intersections and inflection points to reduce total uncertainty in experimental data. This technique was used to reduce uncertainties in sound speed measurements by 80% over conventional methods. Here, we focused on its impact on a previously published set of Mo sound speed data and possible implications for phase transition and geophysical studies. However, this technique's application can be extended to a wide range of experimental data.

The Use of Donation After Cardiac Death Allografts Does Not Increase Recurrence of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) recurrence in patients undergoing liver transplantation (LT) with donation after brain death (DBD) and donation after cardiac death (DCD) allografts has not previously been investigated. Rates and patterns of HCC recurrences were investigated in patients undergoing DBD (N = 1633) and DCD (N = 243) LT between 2003 and 2012. LT for HCC was identified in 397 patients (340 DBD and 57 DCD). No difference in tumor number (p = 0.26), tumor volume (p = 0.34) and serum alphafetoprotein (AFP) (p = 0.47) was seen between the groups. HCC recurrence was identified in 41 (12.1%) patients in the DBD group and 7 (12.3%) patients in the DCD group. There was no difference in recurrence-free survival (p = 0.29) or cumulative incidence of HCC recurrence (p = 0.91) between the groups. Liver allograft was the first site of recurrence in 22 (65%) patients in the DBD group and two (37%) patients in the DCD group (p = 0.39). LT for HCC with DBD and DCD allografts demonstrate no difference in the rate of HCC recurrence. Previously published differences in survival demonstrated between recipients with HCC receiving DBD and DCD allografts despite statistical adjustment can likely be explained by practice patterns not captured by variables contained in the SRTR database.

Abatacept use in graft-versus-host disease after orthotopic liver transplantation: a case report.

BACKGROUND: Graft-versus-host disease (GVHD) is a rare, serious, fatal disease that occurs after orthotopic liver transplantation (OLT). CASE REPORT: We treated a 60-year-old man who underwent OLT owing to familial amyloidosis. The patient developed fever on postoperative day 16. The fever was persistent and did not respond to antibiotic therapy. Cultures and radiologic studies were done and excluded infection as a potential cause. On postoperative day 26, a skin rash appeared on his chest, accompanied by diarrhea and persistent fever. The rash spread all over the trunk, neck, and arms, but spared the palms of his hands and soles of his feet. In the meantime, his blood cell count revealed pancytopenia. Skin biopsy was done and showed interface lymphocytic infiltrate that are largely centered on the dermal-epidermal junction, is consistent with GVHD (this pattern of rash distribution is unique and different from the rash of GVHD after hematopoietic stem cell transplant, which is confined to palms of the hands and soles of the feet; Fig 1). The diagnosis was confirmed by colonoscopy and multiple forceps biopsies, which revealed extensive crypt loss. After hematology consultation, the patient was treated by withdrawal of all immunosuppressive therapy coupled with abatacept infusion. Abatacept is a chimeric protein that inhibits T-lymphocytes and is approved by the US Food and Drug Administration for the treatment of rheumatoid arthritis. Interestingly, after second dose of abatacept the patient showed marked clinical and laboratory improvement. The patient was discharged after 47 days in a stable condition. CONCLUSION: Because of the lack of a consensus for treatment of these patients, we report our experience with a male patient who had post-OLT GVHD and showed a marked improvement in response to abatacept.

Association of surgeon with surgical site infection after liver transplantation.

Surgical site infection (SSI) after liver transplantation has been associated with increased risk of allograft loss and death. Identification of modifiable risk factors for these infections is imperative. To our knowledge, intraoperative practices associated with transplant surgeons have not been assessed as a risk factor. A retrospective cohort study of risk factors for SSI after 1036 first liver transplantations completed by seven surgeons at a single center between 2003 and 2008 was undertaken. Cox proportional hazards models were used to evaluate the association between surgeons and SSIs. SSIs were identified in 166 of 1036 patients (16%). Single variable analysis showed strong evidence of an association between surgeon and SSI (p = 0.0007); the estimated cumulative incidence of SSI ranged from 7% to 24%. This result was consistent in multivariable analysis adjusting for potentially confounding variables (p = 0.002). The occurrence of organ-space or deep SSI varied significantly among surgeons in both single variable analysis (p = 0.005) and multivariable analysis (p = 0.006). These findings provide evidence that differences in the surgical practices of individual surgeons are associated with risk for SSI after liver transplantation. Identification of specific surgical practices associated with risk of SSI is warranted.

Update on biliary strictures in liver transplants.

Biliary complications continue to be the Achilles heel of orthotopic liver transplantation. These include ischemic-type biliary lesions that mostly affect liver allografts donated after cardiac and lead to increased morbidity and retransplantation in patients undergoing liver transplantation. Although this entity has been recognized for >20 years, the true mechanism of injury remains unknown. Identification of the pathogenesis will likely lead to the increased use of grafts donated after cardiac death and thus increase the organ pool. This update reviews the risk factors that have been implicated in ischemic-type biliary lesion formation, potential therapies, and mechanisms that might lead to their formation.

Single-mode fiber, velocity interferometry.

In this paper, we describe a velocity interferometer system based entirely on single-mode fiber optics. This paper includes a description of principles used in developing the single-mode velocity interferometry system (SMV). The SMV design is based on polarization-insensitive components. Polarization adjusters are included to eliminate the effects of residual birefringence and polarization dependent losses in the interferometers. Characterization measurements and calibration methods needed for data analysis and a method of data analysis are described. Calibration is performed directly using tunable lasers. During development, we demonstrated its operation using exploding-foil bridge-wire fliers up to 200 m/s. In a final test, we demonstrated the SMV in a gas gun experiment up to 1.2 km/sec. As a basis for comparison in the gas gun experiment, we used another velocimetry technique that is also based on single-mode fiber optics: photonic Doppler velocimetry (PDV). For the gas gun experiment, we split the light returned from a single target spot and performed a direct comparison of the homodyne (SMV) and heterodyne (PDV) techniques concurrently. The two techniques had a negligible mean difference and a 1.5% standard deviation in the one-dimensional shock zone. Within one interferometer delay time after a sudden Doppler shift, a SMV unencumbered by multimode-fiber dispersion exhibits two color beats. These beats have the same period as PDV beats-this interference occurs between the "recently" shifted and "formerly unshifted" paths within the interferometer. We believe that recognizing this identity between homodyne and heterodyne beats is novel in the shock-physics field. SMV includes the conveniences of optical fiber, while removing the time resolution limitations associated with the multimode delivery fiber.

Graft loss and poor outcomes after living-donor liver transplantation owing to arterioportal shunts caused by liver needle biopsies.

BACKGROUND: Arterioportal shunts (APS) are well-known critical complications after liver transplantation (OLT). The aims of this study were to assess the frequency and causes of APS after OLT and to analyze APS patients with poor outcomes. PATIENTS: We evaluated 1415 OLT recipients retrospectively investigating APS cases. RESULTS: APS were detected in at least 9 patients (0.6%). All patients with APS had a history of posttransplant invasive procedures; percutaneous transhepatic cholangio drainage (n = 6) or needle biopsy (LNB; n = 3). Two patients with poor outcomes showed proximal APS caused by LNBs. The other 7 patients with distal APSs, showed stable conditions. Imaging findings in the 2 proximal APS patients revealed drastic changes in graft hemodynamics. Although they finally underwent re-OLT, their outcomes were poor, owing to fatal complications associated with advanced collaterals. CONCLUSION: We concluded that even careful LNBs can cause APS at unexpected points. Earlier, more aggressive treatments are required, especially for proximal APS patients.

Reactive nodular hyperplasia mimicking malignant lymphoma in donor liver allograft.

The transmission of malignancy from donor to recipient can have devastating outcomes. Therefore, careful examination of the thoracic cavity, abdominal organs, and lymphoid tissue is important. In this report, we have described a case of a healthy 37-year-old donor with no significant past medical history who was found to have a nodule in the liver allograft during the examination at the back table. The frozen section revealed atypical lymphoid hyperplasia. Further workup revealed a rare benign lesion in the liver known as reactive lymphoid hyperplasia. Unfortunately, the liver allograft had to be discarded since low-grade lymphoma could not be excluded at the time of transplantation.

Hashimoto's encephalopathy after interferon therapy for hepatitis C virus in adult liver transplant recipient accompanied by post-transplant lymphoproliferative disorder related to Epstein-Barr virus infection.

A 55-year-old woman underwent living-donor liver transplantation (LDLT). She had no history of autoimmune diseases. Spleen was preserved. Steroids were withdrawn at 3 months after LDLT. Epstein-Barr virus (EBV) infection occurred at 3.5 years after LDLT. Recurrent hepatitis C virus infection was confirmed at 4.5 years after LDLT, and pegylated interferon was introduced. Diagnosis of EBV-positive post-transplant lymphoproliferative disorder (PTLD) was made at 4.8 years after LDLT, and tacrolimus (Tac) was stopped completely. Then, unconsciousness, convulsion, and cervical stiffness appeared suddenly. Electroencephalography, cerebrospinal fluid analysis, and image studies revealed normal or only nonspecific findings. The patient was in a state of exhaustion; therefore, steroid pulse therapy (SPT) was attempted. Surprisingly, her general condition, including consciousness disturbance, was improved markedly, and Hashimoto's encephalopathy (HE) was suspected, based on this reaction to SPT. Elevations of anti-thyroglobulin antibody and anti-thyroid peroxidase antibody were confirmed. After withdrawal of Tac, and treatment with acyclovir and steroids, EBV-positive PTLD and HE improved, although they recurred at 5.1 years after LDLT. SPT improved only neurological symptoms. Molecular-targeted therapy was given for recurrent PTLD, based on analysis of sampling specimens. This therapy was effective, but tumor lysis syndrome occurred, and the patient died at 5.3 years after LDLT.