A population-based cohort study

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What every Intensivist should know about the role of ammonia in liver failure

Publisher Copyright: © 2023 The AuthorsPurpose: Acute liver failure (ALF) or acute-on-chronic liver failure (ACLF) patients have high short-term mortality and morbidity. In the context of liver failure, increased serum ammonia is associated with worse neurological outcomes, including high-grade hepatic encephalopathy (HE), cerebral edema, and intracranial hypertension. Besides its neurotoxicity, hyperammonemia may contribute to immune dysfunction and the risk of infection, a frequent trigger for multi-organ failure in these patients. Material and methods: We performed a literature-based narrative review. Publications available in PubMed® up to June 2023 were considered. Results: In the ICU management of liver failure patients, serum ammonia may play an important role. Accordingly, in this review, we focus on recent insights about ammonia metabolism, serum ammonia measurement strategies, hyperammonemia prognostic value, and ammonia-targeted therapeutic strategies. Conclusions: Serum ammonia may have prognostic value in liver failure. Effective ammonia targeted therapeutic strategies are available, such as laxatives, rifaximin, L-ornithine-L-aspartate, and continuous renal replacement therapy.proofepub_ahead_of_prin

A population-based cohort study

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Scientists warning to humanity on insect extinctions

Here we build on the manifesto 'World Scientists' Warning to Humanity, issued by the Alliance of World Scientists. As a group of conservation biologists deeply concerned about the decline of insect populations, we here review what we know about the drivers of insect extinctions, their consequences, and how extinctions can negatively impact humanity. We are causing insect extinctions by driving habitat loss, degradation, and fragmentation, use of polluting and harmful substances, the spread of invasive species, global climate change, direct overexploitation, and co-extinction of species dependent on other species. With insect extinctions, we lose much more than species. We lose abundance and biomass of insects, diversity across space and time with consequent homogenization, large parts of the tree of life, unique ecological functions and traits, and fundamental parts of extensive networks of biotic interactions. Such losses lead to the decline of key ecosystem services on which humanity depends. From pollination and decomposition, to being resources for new medicines, habitat quality indication and many others, insects provide essential and irreplaceable services. We appeal for urgent action to close key knowledge gaps and curb insect extinctions. An investment in researc

a cohort study

Funding: This work was supported by grants from the National Institutes of Health (U19AI135964, P30AG059988), with institutional support from UL1TR001422. The funding agency played no role in the study design, collection of data, analysis, or interpretation of data.The impact of multidrug-resistant (MDR) colonization and MDR infection in critically ill cirrhosis patients remains unclear. We assessed the association of MDR colonization and MDR infection with these patients' survival. Observational cohort study including adult cirrhosis patients admitted to 5 intensive care units at Northwestern Memorial Hospital (Chicago, Illinois, USA) on January 1, 2010, to December 31, 2017. Patients admitted for elective liver transplant or with previous liver transplant were excluded. Patients were screened for MDR colonization on intensive care unit admission. Infection diagnoses during the intensive care unit stay were considered. The primary endpoint was hospital transplant-free survival. Among 600 patients included, 362 (60%) were men and median (interquartile range) age was 58.0 (49.0, 64.0) years. Median (interquartile range) Model for End-stage Liver Disease, Sequential Organ Failure Assessment, and Chronic Liver Failure-Acute-on-Chronic Liver Failure scores on intensive care unit day 1 were 28.0 (20.0, 36.0), 9.0 (6.0, 13.0), and 55.0 (48.0, 64.0), respectively. Overall, 76 (13%) patients were transplanted and 443 (74%) survived the hospital stay. Infections were diagnosed in 347 (58%) patients: pneumonia in 197 (33%), urinary tract infection in 119 (20%), peritonitis in 93 (16%), bloodstream infection in 99 (16%), Clostridium difficile colitis in 9 (2%), and catheter tip infection in 7 (1%). MDR colonization and MDR infection were identified in 200 (33%) and 69 (12%) patients, respectively. MDR colonization was associated with MDR infection (p < 0.001). MDR colonization or MDR infection was associated with higher number and duration of antibiotics (p < 0.001). Following adjustment for covariables (age, sex, etiology, portal hypertension, and Sequential Organ Failure Assessment score), MDR colonization [OR (95% CI), 0.64 (0.43, 0.95)] or MDR infection [adjusted OR (95% CI), 0.22 (0.12, 0.40)] were independently associated with lower transplant-free survival. Among critically ill cirrhosis patients, MDR colonization or MDR infection portended a worse prognosis.publishersversionpublishe

Production and Characterization of Graphene Oxide Surfaces against Uropathogens

Graphene and its functionalized derivatives have been increasingly applied in the biomedi-cal field, particularly in the production of antimicrobial and anti-adhesive surfaces. This study aimed to evaluate the performance of graphene oxide (GO)/polydimethylsiloxane (PDMS) composites against Staphylococcus aureus and Pseudomonas aeruginosa biofilms. GO/PDMS composites containing different GO loadings (1, 3, and 5 wt.%) were synthesized and characterized regarding their morphol-ogy, roughness, and hydrophobicity, and tested for their ability to inhibit biofilm formation under conditions that mimic urinary tract environments. Biofilm formation was assessed by determining the number of total and culturable cells. Additionally, the antibacterial mechanisms of action of GO were investigated for the tested uropathogens. Results indicated that the surfaces containing GO had greater roughness and increased hydrophobicity than PDMS. Biofilm analysis showed that the 1 wt.% GO/PDMS composite was the most effective in reducing S. aureus biofilm formation. In oppo-sition, P. aeruginosa biofilms were not inhibited by any of the synthesized composites. Furthermore, 1% (w/v) GO increased the membrane permeability, metabolic activity, and endogenous reactive oxygen species (ROS) synthesis in S. aureus. Altogether, these results suggest that GO/PDMS com-posites are promising materials for application in urinary catheters, although further investigation is required

Higher-Derivative Corrected Black Holes: Perturbative Stability and Absorption Cross-Section in Heterotic String Theory

This work addresses spherically symmetric, static black holes in higher-derivative stringy gravity. We focus on the curvature-squared correction to the Einstein-Hilbert action, present in both heterotic and bosonic string theory. The string theory low-energy effective action necessarily describes both a graviton and a dilaton, and we concentrate on the Callan-Myers-Perry solution in d-dimensions, describing stringy corrections to the Schwarzschild geometry. We develop the perturbation theory for the higher-derivative corrected action, along the guidelines of the Ishibashi-Kodama framework, focusing on tensor type gravitational perturbations. The potential obtained allows us to address the perturbative stability of the black hole solution, where we prove stability in any dimension. The equation describing gravitational perturbations to the Callan-Myers-Perry geometry also allows for a study of greybody factors and quasinormal frequencies. We address gravitational scattering at low frequencies, computing corrections arising from the curvature-squared term in the stringy action. We find that the absorption cross-section receives \alpha' corrections, even though it is still proportional to the area of the black hole event-horizon. We also suggest an expression for the absorption cross-section which could be valid to all orders in \alpha'.Comment: JHEP3.cls, 29 pages; v2: added refs, minor corrections and additions; v3: added more refs, more minor corrections and addition

A Cohort Analysis

Publisher Copyright: © 2022Background and Aims: The donor risk index (DRI) quantifies donor-related characteristics potentially associated with increased risk of early graft failure. We aimed to assess the impact of the DRI, recipient and perioperative factors on post liver transplant (LT) outcomes. Methods: This was a single-center retrospective cohort study including all adult (≥18 years) patients who underwent LT from 01/2019 to 12/2019 at Curry Cabral Hospital, Lisbon, Portugal. Primary endpoint was 1-year graft failure post LT. Associations were studied with logistic regression. Results: A total of 131 cadaveric donor LT procedures were performed in 116 recipients. Recipients' median (IQR) age was 57 (47-64) years and 101/131 (77.1%) were males. Cirrhosis was the underlying etiology in 95/131 (81.2%) transplants. Based on 8 predefined donors' characteristics, median (IQR) DRI was 1.96 (1.67-2.16). Following adjustment for MELDNa score pre LT and SOFA score (adjusted odds ratio [aOR], 95% confidence interval [CI] = 0.91 [0.56-1.47]) or lactate (aOR [95% CI] = 2.76 [0.71-10.7]) upon intensive care unit (ICU) admission post LT, DRI was not associated with 1-year graft failure. However, higher SOFA score (aOR [95% CI] = 1.20 [1.05-1.37]) or lactate (aOR [95% CI] = 1.27 [1.10-1.46]) upon ICU admission post LT were independently associated with higher odds of 1-year graft failure. Conclusions: In a recent cohort of patients who underwent LT, DRI, despite being high, was not associated with 1-year graft failure, but SOFA score or lactate upon ICU admission post LT were.publishersversionepub_ahead_of_prin

A Cross-Sectional Study

Publisher Copyright: © 2022 The Author(s). Published by S. Karger AG, Basel. This article is licensed under the Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC). Usage and distribution for commercial purposes requires written permission.Background: Listing patients with alcohol-associated liver disease (ALD) for liver transplant (LT) remains challenging especially due to the risk of alcohol resumption post-LT. We aimed to evaluate post-LT alcohol consumption at a Portuguese transplant center. Methods: We conducted a cross-sectional study including LT recipients from 2019 at Curry Cabral Hospital, Lisbon, Portugal. A pretested survey and a validated Portuguese translation of the Alcohol Use Disorder Identification Test (AUDIT) were applied via a telephone call. Alcohol consumption was defined by patients' self-reports or a positive AUDIT. Results: In 2019, 122 patients underwent LT, and 99 patients answered the survey (June 2021). The mean (SD) age was 57 (10) years, 70 patients (70.7%) were males, and 49 (49.5%) underwent ALD-related LT. During a median (IQR) follow-up of 24 (20-26) months post-index LT, 22 (22.2%) recipients consumed any amount of alcohol: 14 had a drink monthly or less and 8 drank 2-4 times/month. On drinking days, 18 patients usually consumed 1-2 drinks and the remainder no more than 3-4 drinks. One patient reported having drunk ≥6 drinks on one occasion. All post-LT drinking recipients were considered low risk (score <8) as per the AUDIT score (median [IQR] of 1 [1-2]). No patient reported alcohol-related problems, whether self-inflicted or toward others. Drinking recipients were younger (53 vs. 59 years, p = 0.020), had more non-ALD-related LT (72.7 vs. 44.2%, p = 0.018) and active smoking (31.8 vs. 10.4%, p = 0.037) than abstinent ones. Conclusion: In our cohort, about a quarter of LT recipients consumed alcohol early posttransplant, all with a low-risk pattern according to the AUDIT score.publishersversionepub_ahead_of_prin