Tumore des biliären Trakts: Häufigkeit, Diagnostik und Therapie

Die malignen Tumoren des biliären Trakts, unterteilt in Gallenblasen- und Gallengangskarzinome, sind eher selten. Dennoch wurden in den vergangenen Jahren Fortschritt in Diagnostik und Therapie erzielt. Neben Verbesserung der operativen Techniken als einzige kurative Option konnte auch ein chemotherapeutischer Standard bei fortgeschrittenen Tumoren etabliert werden. Multimodal Konzepte stehen im Fokus des Forschungsinteresses

Reconstruction of Network Evolutionary History from Extant Network Topology and Duplication History

Genome-wide protein-protein interaction (PPI) data are readily available thanks to recent breakthroughs in biotechnology. However, PPI networks of extant organisms are only snapshots of the network evolution. How to infer the whole evolution history becomes a challenging problem in computational biology. In this paper, we present a likelihood-based approach to inferring network evolution history from the topology of PPI networks and the duplication relationship among the paralogs. Simulations show that our approach outperforms the existing ones in terms of the accuracy of reconstruction. Moreover, the growth parameters of several real PPI networks estimated by our method are more consistent with the ones predicted in literature.Comment: 15 pages, 5 figures, submitted to ISBRA 201

Viability Assessment in Liver Transplantation—What Is the Impact of Dynamic Organ Preservation?

Based on the continuous increase of donor risk, with a majority of organs classified as marginal, quality assessment and prediction of liver function is of utmost importance. This is also caused by the notoriously lack of effective replacement of a failing liver by a device or intensive care treatment. While various parameters of liver function and injury are well-known from clinical practice, the majority of specific tests require prolonged diagnostic time and are more difficult to assess ex situ. In addition, viability assessment of procured organs needs time, because the development of the full picture of cellular injury and the initiation of repair processes depends on metabolic active tissue and reoxygenation with full blood over several hours or days. Measuring injury during cold storage preservation is therefore unlikely to predict the viability after transplantation. In contrast, dynamic organ preservation strategies offer a great opportunity to assess organs before implantation through analysis of recirculating perfusates, bile and perfused liver tissue. Accordingly, several parameters targeting hepatocyte or cholangiocyte function or metabolism have been recently suggested as potential viability tests before organ transplantation. We summarize here a current status of respective machine perfusion tests, and report their clinical relevance

Procalcitonin in early allograft dysfunction after orthotopic liver transplantation: a retrospective single centre study

Background: Ischemia-reperfusion injury (IRI) is the pathophysiological hallmark of hepatic dysfunction after orthotopic liver transplantation (OLT). Related to IRI, early allograft dysfunction (EAD) after OLT affects short- and long-term outcome. During inflammatory states, the liver seems to be the main source of procalcitonin (PCT), which has been shown to increase independently of bacterial infection. This study investigates the association of PCT, IRI and EAD as well as the predictive value of PCT during the first postoperative week in terms of short- and long-term outcome after OLT. Methods: Patients ≥ 18 years undergoing OLT between January 2016 and April 2020 at the University Hospital of Zurich were eligible for this retrospective study. Patients with incomplete PCT data on postoperative days (POD) 1 + 2 or combined liver-kidney transplantation were excluded. The PCT course during the first postoperative week, its association with EAD, defined by the criteria of Olthoff, and IRI, defined as aminotransferase level > 2000 IU/L within 2 PODs, were analysed. Finally, 90-day as well as 12-month graft and patient survival were assessed. Results: Of 234 patients undergoing OLT, 110 patients were included. Overall, EAD and IRI patients had significantly higher median PCT values on POD 2 [31.3 (9.7-53.8) mcg/l vs. 11.1 (5.3-25.0) mcg/l; p 15 mcg/l on POD 2 was comparable to that of patients without IRI/EAD. Conclusion: Generally, PCT is increased in the early postoperative phase after OLT. Patients with EAD and IRI have a significantly increased PCT maximum on POD 2, and impaired 90-day graft survival. PCT measurement may have potential as an additional outcome predictor in the early phase after OLT, as in our subanalysis of IRI patients, PCT values < 15 mcg/l were associated with impaired outcome. Keywords: Donation after brain death; Donation after cardiac death; Early allograft dysfunction; Ischemia–reperfusion injury; Orthotopic liver transplantation; Outcome; Primary nonfunction; Procalcitonin

Comparative Study of Acute Kidney Injury in Liver Transplantation: Donation after Circulatory Death versus Brain Death

BACKGROUND Acute kidney injury (AKI) after orthotopic liver transplantation (OLT) contributes to morbidity and mortality. Donation after circulatory death (DCD) has been established to increase the pool of organs. While surgical complications are reported to be comparable in DCD and donation after brain death (DBD) OLT, there is a knowledge gap concerning adverse kidney events in these 2 groups. MATERIAL AND METHODS In this retrospective cohort study, 154 patients received a DBD and 68 received a DCD organ (2016-2020). The primary outcome was a major adverse kidney event within 30 days (MAKE-30). The secondary outcome was dynamics of AKI and kidney replacement therapy (KRT) during the first postoperative week and on postoperative day 30. Incidence and resolution from AKI and KRT and patient survival (PS) 30 days after OLT were compared between the DCD and DBD recipients. RESULTS MAKE-30 incidence after OLT was comparable in DCD (n=27, 40%) vs DBD (n=41, 27%) recipients (risk ratio 1.49 [95% CI 1.01, 2.21], p=0.073). AKI incidence was comparable in DCD (n=58, 94%) vs DBD (n=95, 82%) recipients (risk ratio 1.14 [95% CI: 1.03, 1.27], P=0.057). Overall, 40% (n=88) of patients required KRT, with no difference between DCD (n=27, 40%) vs DBD (n=61, 40%) recipients (risk ratio 1.00 [95% CI 0.71, 1.43], P>0.999). Resolution of AKI by day 30 was lower in DCD (n=29, 50%) than in DBD (n=66, 69%) recipients (risk ratio 0.71 [95% CI: 0.53, 0.95], P=0.032). Survival after 30 days (DCD: n=64, 94% vs DBD: n=146, 95%, risk ratio 0.99 [95% CI 0.93, 1.06], P>0.999) was also comparable. CONCLUSIONS MAKE-30, short-term renal outcome, and survival did not significantly differ between DBD and DCD-OLT. Resolution of AKI by day 30 was lower in DCD than in DBD recipients

Model of end stage liver disease (MELD) score greater than 23 predicts length of stay in the ICU but not mortality in liver transplant recipients

INTRODUCTION: The impact of model of end stage liver disease (MELD) score on postoperative morbidity and mortality is still elusive, especially for high MELD. There are reports of poorer patient outcome in transplant candidates with high MELD score, others though report no influence of MELD score on outcome and survival. METHODS: We retrospectively analyzed data of 144 consecutive liver transplant recipients over a 72-month period in our transplant unit, from January 2003 until December 2008 and performed uni- and multivariate analysis for morbidity and mortality, in particular to define the influence of MELD to these parameters. RESULTS: This study identified MELD score greater than 23 as an independent risk factor of morbidity represented by intensive care unit (ICU) stay longer than 10 days (odds ratio 7.0) but in contrast had no negative impact on mortality. Furthermore, we identified transfusion of more than 7 units of red blood cells as independent risk factor for mortality (hazard ratio 7.6) and for prolonged ICU stay (odds ratio [OR] 7.8) together with transfusion of more than 10 units of fresh frozen plasma (OR 11.6). Postoperative renal failure is a strong predictor of morbidity (OR 7.9) and postoperative renal replacement therapy was highly associated with increased mortality (hazard ratio 6.8), as was hepato renal syndrome prior to transplantation (hazard ratio 13.2). CONCLUSIONS: This study identified MELD score greater than 23 as an independent risk factor of morbidity represented by ICU stay longer than 10 days but in contrast had no negative impact on mortality. This finding supports the transplantation of patients with high MELD score but only with knowledge of increased morbidity

Domain-oriented edge-based alignment of protein interaction networks

Motivation: Recent advances in high-throughput experimental techniques have yielded a large amount of data on protein–protein interactions (PPIs). Since these interactions can be organized into networks, and since separate PPI networks can be constructed for different species, a natural research direction is the comparative analysis of such networks across species in order to detect conserved functional modules. This is the task of network alignment

Network Archaeology: Uncovering Ancient Networks from Present-day Interactions

Often questions arise about old or extinct networks. What proteins interacted in a long-extinct ancestor species of yeast? Who were the central players in the Last.fm social network 3 years ago? Our ability to answer such questions has been limited by the unavailability of past versions of networks. To overcome these limitations, we propose several algorithms for reconstructing a network's history of growth given only the network as it exists today and a generative model by which the network is believed to have evolved. Our likelihood-based method finds a probable previous state of the network by reversing the forward growth model. This approach retains node identities so that the history of individual nodes can be tracked. We apply these algorithms to uncover older, non-extant biological and social networks believed to have grown via several models, including duplication-mutation with complementarity, forest fire, and preferential attachment. Through experiments on both synthetic and real-world data, we find that our algorithms can estimate node arrival times, identify anchor nodes from which new nodes copy links, and can reveal significant features of networks that have long since disappeared.Comment: 16 pages, 10 figure

On dynamic network entropy in cancer

The cellular phenotype is described by a complex network of molecular interactions. Elucidating network properties that distinguish disease from the healthy cellular state is therefore of critical importance for gaining systems-level insights into disease mechanisms and ultimately for developing improved therapies. By integrating gene expression data with a protein interaction network to induce a stochastic dynamics on the network, we here demonstrate that cancer cells are characterised by an increase in the dynamic network entropy, compared to cells of normal physiology. Using a fundamental relation between the macroscopic resilience of a dynamical system and the uncertainty (entropy) in the underlying microscopic processes, we argue that cancer cells will be more robust to random gene perturbations. In addition, we formally demonstrate that gene expression differences between normal and cancer tissue are anticorrelated with local dynamic entropy changes, thus providing a systemic link between gene expression changes at the nodes and their local network dynamics. In particular, we also find that genes which drive cell-proliferation in cancer cells and which often encode oncogenes are associated with reductions in the dynamic network entropy. In summary, our results support the view that the observed increased robustness of cancer cells to perturbation and therapy may be due to an increase in the dynamic network entropy that allows cells to adapt to the new cellular stresses. Conversely, genes that exhibit local flux entropy decreases in cancer may render cancer cells more susceptible to targeted intervention and may therefore represent promising drug targets.Comment: 10 pages, 3 figures, 4 tables. Submitte