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.

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.

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.

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.

The diagnostic conundrum and liver transplantation outcome for combined hepatocellular-cholangiocarcinoma.

Combined hepatocellular-cholangiocarcinoma (cHCC-CC) is a rare primary liver malignancy with mixed hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) histological features. It is almost impossible to obtain an accurate, preoperative noninvasive diagnosis of cHCC-CC with tumor markers or cross-sectional abdominal imaging due to the mixed histological features. Despite these difficulties, accurate cHCC-CC diagnosis remains an important goal with prognostic significance. In our study, we retrospectively reviewed the tumor markers: AFP and CA 19-9, and cross-sectional liver imaging, in light of liver explant findings, to identify and characterize cHCC-CC features followed by liver transplantation (LT) outcome analysis. The results from this 12 patient cohort failed to identify characteristic features for cHCC-CC. None of the imaging features helped to identify the cHCC-CC tumor and they mimicked either HCC or CC, depending on the degree of glandular differentiation expressed histologically. In our cHCC-CC LT recipients, the 1-, 3- and 5-year cumulative survival probabilities were 79%, 66% and 16%, respectively with a 5-year survival comparable to or better than LT for intrahepatic CC but poorer than LT for HCC following the Milan criteria. Conceivably explained by its cholangiocarcinoma component the LT outcome for this rare and hard to diagnose tumor appears poor.

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.

Herpes simplex virus hepatitis after pediatric liver transplantation.

Herpes simplex virus (HSV) hepatitis has a fatal impact on the outcome of organ transplanted recipients. Here, we present a thought-provoking case of HSV hepatitis in a high-risk recipient after living-related liver transplantation (LRLT). A 1-month-old female newborn infant was affected by HSV encephalitis. Fulminant hepatic failure (FHF) of unknown etiology occurred suddenly at 4.4 years of age. Viral infections were ruled out as the cause of FHF. Intensive care including plasma exchange (PE) was started, and the preoperative treatments for ABO incompatibility were performed. Thereafter, LRLT was performed emergently. Although strong immunosuppression for ABO incompatibility was continued after LRLT, antibody-mediated rejection (AMR) occurred on postoperative day (POD) 4. PE was repeated and improvements were obtained. However, liver dysfunction appeared on POD 8. Histopathological findings of liver needle biopsy clearly revealed HSV hepatitis, although the results of HSV DNA and antibody titer in blood sample did not clearly indicate HSV infection. On POD 21, thrombotic microangiopathy (TMA) occurred and the plasma and immunoglobulin were replenished. Our pediatric recipient recovered successfully from AMR, HSV hepatitis, TMA, and repeated sepsis. We conclude that well considered therapy based on the real-time detection of HSV hepatitis is indispensable for the further improvements of outcome in HSV hepatitis after LRLT.

Interposition graft with polytetrafluoroethylene for mesenteric and portal vein reconstruction after pancreaticoduodenectomy.

BACKGROUND: Portal vein-superior mesenteric vein resection is frequently required after surgical resection of tumours of the pancreas head. The ideal graft for portal vein reconstruction (PVR) remains undefined. METHODS: Between May 2000 and July 2007, 28 patients had portal vein-superior mesenteric vein resection and PVR during pancreaticoduodenectomy. Their clinical reports were reviewed retrospectively with specific attention to the methods of PVR and outcomes. RESULTS: Ten patients had PVR with primary anastomosis, seven had PVR with autologous vein, one had a polytetrafluoroethylene (PTFE) patch, one did not have PVR and nine had PVR with a PTFE interposition graft. There was no infection after PTFE grafting. Six patients had PVR thrombosis after surgery: four after primary anastomosis, one after interposition PTFE and one after vein repair. CONCLUSION: PTFE appeared to be an effective and safe option as an interposition graft for portomesenteric venous reconstruction after pancreaticoduodenectomy.

Dissociation of CH4 at high pressures and temperatures: diamond formation in giant planet interiors?

Experiments using laser-heated diamond anvil cells show that methane (CH4) breaks down to form diamond at pressures between 10 and 50 gigapascals and temperatures of about 2000 to 3000 kelvin. Infrared absorption and Raman spectroscopy, along with x-ray diffraction, indicate the presence of polymeric hydrocarbons in addition to the diamond, which is in agreement with theoretical predictions. Dissociation of CH4 at high pressures and temperatures can influence the energy budgets of planets containing substantial amounts of CH4, water, and ammonia, such as Uranus and Neptune.

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.

Mesocaval shunt as an alternative treatment for persistent ascites after liver transplantation: case reports.

Refractory ascites after liver transplantation is a relatively rare complication. If the initial medical treatment fails, more invasive techniques may be required. The TIPS procedure has emerged as a major treatment option for decompression of the portal venous system. Mesocaval shunt can be an alternative to TIPS in selected cases. We describe two patients who underwent mesocaval shunt construction for refractory ascites.

Primary nonfunction in liver transplantation: a single-center experience.

Primary nonfunction (PNF) after liver transplantation is life threatening. In recent review of data from Scientific Registry of Transplant Recipients on liver transplantations between 2002 and 2004, the rate of PNF was 5.8%. In this study, our aim was to review the incidence and outcome of PNF at our transplant center. From February 1998 through December 2007, 1679 liver transplants were performed. There were 24 PNF (1.4%) in 22 patients. The 6- and 12-month patient survival rates were 72.2% and 63.3%, respectively. Our results demonstrate a low incidence of PNF at our center. However, the patient survival outcome remains poor. Future investigations to improve survival among liver transplant recipients with PNF are essential.

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.

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.

Splenic embolization in liver transplant recipients: early outcomes.

Clinical improvement has been reported following splenic embolization for a wide variety of indications. Improvement following splenic embolization has been described in cirrhotic patients awaiting hepatic transplantation who are not candidates for surgical splenectomy. Occasionally, patients who have undergone hepatic transplantation have conditions that may also benefit from nonsurgical intervention with splenic embolization. Indications include persistent hypersplenism and pancytopenia precluding optimal treatment with antiviral therapy or chemotherapy, risk for persistent gastroesophageal variceal hemorrhage, and splenic artery steal syndrome attenuating hepatic arterial perfusion. Limited data is available on the outcome of splenic embolization in liver transplant recipients. We present the early outcomes of liver transplant recipients who were treated with splenic embolization. A retrospective chart review of all liver transplant recipients who underwent splenic embolization between 1997 and 2006 was performed, under minimal-risk study approval by the institutional review board. Five liver transplant recipients received splenic embolization: 3 for persistent hypersplenism, 1 for increased risk of gastroesophageal variceal hemorrhage, and 1 for splenic artery steal syndrome. The patients with hypersplenism demonstrated hematologic improvement, the patient with gastroesophageal varices did not experience any hemorrhage on follow-up, and the patient with splenic artery steal experienced resolution of the steal phenomenon. Postembolization syndrome was observed but no splenic abscess or death occurred. Mean follow-up was 20.2 months. In conclusion, splenic embolization is a safe and effective nonsurgical alternative for a variety of indications in liver transplant recipients.