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BACKGROUND: Increasing evidence suggests that secondary sclerosing cholangitis (SSC), which can lead to cirrhosis or liver failure, may be a hepatobiliary long-term complication of COVID-19. The aim of this study was to estimate the frequency and outcome of this COVID-19 sequela and to identify possible risk factors. METHODS: This observational study, conducted at University Hospital Charité Berlin and Unfallkrankenhaus Berlin, Germany, involved hospitalized patients with COVID-19 pneumonia, including 1082 ventilated COVID-19 patients. We compared COVID-19 patients who developed SSC with a COVID-19 control group by univariate and multivariate analyses. RESULTS: SSC occurrence after COVID-19 was observed exclusively in critically ill patients with invasive ventilation, albeit with extreme clustering among them. One in every 43 invasively ventilated COVID-19 patients developed this complication. Risk factors preceding the development of secondary sclerosing cholangitis in critically ill COVID-19 patients (SSC-CIP) were signs of systemic reduced blood oxygen supply (e.g., low PaO(2)/FiO(2), ischemic organ infarctions), multi-organ failure (high SOFA score) at admission, high fibrinogen levels and intravenous ketamine use. Multivariate analysis confirmed fibrinogen and increased plasma lactate dehydrogenase as independent risk factors associated with cholangiopathy onset. The 1-year transplant-free survival rate of COVID-19-associated SSC-CIP was 40%. CONCLUSIONS: COVID-19 causes SSC-CIP in a substantial proportion of critically ill patients. SSC-CIP most likely develops due to severe tissue hypoxia and fibrinogen-associated circulatory disturbances. A significant increase of patients with SSC-CIP is to be expected in the post-COVID era.

Introduction Acute kidney injury (AKI) is an important complication in COVID-19, but its precise etiology has not fully been elucidated. Insights into AKI mechanisms may be provided by analyzing the temporal associations of clinical parameters reflecting disease processes and AKI development. Methods We performed an observational cohort study of 223 consecutive COVID-19 patients treated at 3 sites of a tertiary care referral center to describe the evolvement of severe AKI (Kidney Disease: Improving Global Outcomes stage 3) and identify conditions promoting its development. Descriptive statistics and explanatory multivariable Cox regression modeling with clinical parameters as time-varying covariates were used to identify risk factors of severe AKI. Results Severe AKI developed in 70 of 223 patients (31%) with COVID-19, of which 95.7% required kidney replacement therapy. Patients with severe AKI were older, predominantly male, had more comorbidities, and displayed excess mortality. Severe AKI occurred exclusively in intensive care unit patients, and 97.3% of the patients developing severe AKI had respiratory failure. Mechanical ventilation, vasopressor therapy, and inflammatory markers (serum procalcitonin levels and leucocyte count) were independent time-varying risk factors of severe AKI. Increasing inflammatory markers displayed a close temporal association with the development of severe AKI. Sensitivity analysis on risk factors of AKI stage 2 and 3 combined confirmed these findings. Conclusion Severe AKI in COVID-19 was tightly coupled with critical illness and systemic inflammation and was not observed in milder disease courses. These findings suggest that traditional systemic AKI mechanisms rather than kidney-specific processes contribute to severe AKI in COVID-19., Graphical abstract

Die therapeutische Gabe von Blut und Blutkomponenten ist auch heute noch mit potenziellen Nebenwirkungen und Risiken verbunden. Auserdem konnen Blutkonserven zunehmend nicht mehr in ausreichendem Umfang zur Verfugung gestellt werden. Diese Umstande und die positive Erfahrung der erfolgreichen Behandlung verschiedener Anamieformen mit rekombinantem humanen Erythropoietin (rHuEPO) haben dazu gefuhrt, dass in den letzten Jahren das Interesse an der lange wenig beachteten Anamie des kritisch kranken Patienten stark zugenommen hat. Wie bei der Anamie chronischer Erkrankungen sind die Ursachen der Anamie kritisch kranker Patienten vielfaltig: vorbestehende Anamie, Blutverluste, inadaquate endogene Erythropoietinproduktion, verkurzte Erythrozytenlebensdauer, verminderte Eisenverfugbarkeit und eine direkte Hemmung der Erythropoiese durch Zytokine tragen zur Entwicklung dieser Anamie bei. Die Bedeutung der Anamie fur Verlauf und Prognose kritisch kranker Patienten ist nicht geklart, und es gibt bislang keine eindeutigen Empfehlungen fur ein optimales Therapiemanagement. rHuEPO hat sich neben Strategien zur Vermeidung von Blutverlusten als attraktive Therapieoption erwiesen, die gegenwartig in Studien evaluiert wird. The transfusion of red blood cells is still associated with possible adverse effects and a residual risk of transmission of viral and nonviral diseases. In addition, there is an increasing shortage of blood supply worldwide. These two facts together with the success experienced in the treatment of various types of anemia with recombinant human EPO, have recently led to an increasing interest in the anemia of critically ill patients. As in the anemia of chronic diseases there are several reasons that contribute to the development of anemia in patients on intensive care units: pre-existing anemia, blood loss, reduced red cell life span, impaired iron availbility and a direct inhibition of erythropoiesis by inflammatory cytokines. The implications of anemia for the progression and prognosis of critical illness are still unclear and the optimal treatment, including optimal “transfusion triggers” remains controversial. Recombinant human EPO has been proven to be effective in ameliorating the anemia of critical illness in several pilot studies and is currently being tested in larger trials.

Udgivelsesdato: 2000-null A method for quantitating proteins and peptides in the low picomole and sub-picomole range has been developed using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) with internal (18)O-labeled standards. A simple procedure is proposed to produce such internal standards for the tested sample by enzymatic hydrolysis of the same sample (with known concentration) in (18)O-water. A mathematical algorithm was developed which uses the isotopic patterns of the substance, the internal standard, and the substance/internal standard mixture for accurate quantitation of the substance. A great advantages of the proposed method is the absence of molecular weight limitation for the protein quantitation and the possibility of quantitation without previous fractionation of proteins and peptides. Using this strategy, the peptide angiotensinogen and two proteins, RNase and its protein inhibitor, were quantified by MALDI-time-of-flight (TOF) mass spectrometry.

Udgivelsesdato: 1999-Apr A series of hexa- to decapeptides (molecular mass range 800-1200) were labeled with naphthalene-2,3-dicarboxaldehyde, which preferentially reacts with the primary amino groups of a peptide. A highly stable peptide conjugate is formed, which allows selective analysis by fluorescence at excitation and emission wavelengths of 420 and 490 nm, respectively. After removal of unreacted compounds, the peptide conjugates were characterized by matrix-assisted laser desorption/ionization (MALDI) time-of-flight and nano-electrospray ionization (ESI) ion trap mass spectrometry. They readily form both [M + H]+ ions by MALDI and both [M + H]+ and [M + 2H]2+ ions by ESI. Furthermore, the fragmentation behavior of the N-terminally tagged peptides, exhibiting an uncharged N-terminus, was investigated applying post-source decay fragmentation with a curved field reflector and collision-induced dissociation with a quadrupole ion trap. Fragmentation is dominated in both cases by series of a-, b- and y-type ions and [M + H - HCN]+ ions. Peptide bonds adjacent to the fluorescence label were less susceptible to cleavage than the bonds of the non-derivatized peptide ions. In general, the resulting fragment ion patterns were less complex than those of the underivatized peptides.

The estimation of accuracy and applicability of QSAR and QSPR models for biological and physicochemical properties represents a critical problem. The developed parameter of "distance to model" (DM) is defined as a metric of similarity between the training and test set compounds that have been subjected to QSAR/QSPR modeling. In our previous work, we demonstrated the utility and optimal performance of DM metrics that have been based on the standard deviation within an ensemble of QSAR models. The current study applies such analysis to 30 QSAR models for the Ames mutagenicity data set that were previously reported within the 2009 QSAR challenge. We demonstrate that the DMs based on an ensemble (consensus) model provide systematically better performance than other DMs. The presented approach identifies 30-60% of compounds having an accuracy of prediction similar to the interlaboratory accuracy of the Ames test, which is estimated to be 90%. Thus, the in silico predictions can be used to halve the cost of experimental measurements by providing a similar prediction accuracy. The developed model has been made publicly available at http://ochem.eu/models/1 .

The Online Chemical Modeling Environment is a web-based platform that aims to automate and simplify the typical steps required for QSAR modeling. The platform consists of two major subsystems: the database of experimental measurements and the modeling framework. A user-contributed database contains a set of tools for easy input, search and modification of thousands of records. The OCHEM database is based on the wiki principle and focuses primarily on the quality and verifiability of the data. The database is tightly integrated with the modeling framework, which supports all the steps required to create a predictive model: data search, calculation and selection of a vast variety of molecular descriptors, application of machine learning methods, validation, analysis of the model and assessment of the applicability domain. As compared to other similar systems, OCHEM is not intended to re-implement the existing tools or models but rather to invite the original authors to contribute their results, make them publicly available, share them with other users and to become members of the growing research community. Our intention is to make OCHEM a widely used platform to perform the QSPR/QSAR studies online and share it with other users on the Web. The ultimate goal of OCHEM is collecting all possible chemoinformatics tools within one simple, reliable and user-friendly resource. The OCHEM is free for web users and it is available online at http://www.ochem.eu . © 2011 The Author(s).