RESUMO
The mucus serves as a protective barrier in the gastrointestinal tract against microbial attacks. While its role extends beyond merely being a physical barrier, the extent of its active bactericidal properties remains unclear, and the mechanisms regulating these properties are not yet understood. We propose that inflammation induces epithelial cells to secrete antimicrobial peptides, transforming mucus into an active bactericidal agent. To investigate the properties of mucus, we previously developed mucosoid culture models that mimic the healthy human stomach epithelium. Similar to organoids, mucosoids are stem cell-driven cultures; however, the cells are cultivated on transwells at air-liquid interface. The epithelial cells of mucosoids form a polarized monolayer, allowing differentiation into all stomach lineages, including mucus-secreting cells. This setup facilitates the secretion and accumulation of mucus on the apical side of the mucosoids, enabling analysis of its bactericidal effects and protein composition, including antimicrobial peptides. Our findings show that TNFα, IL1ß, and IFNγ induce the secretion of antimicrobials such as lactotransferrin, lipocalin2, complement component 3, and CXCL9 into the mucus. This antimicrobial-enriched mucus can partially eliminate Helicobacter pylori, a key stomach pathogen. The bactericidal activity depends on the concentration of each antimicrobial and their gene expression is higher in patients with inflammation and H.pylori-associated chronic gastritis. However, we also find that H. pylori infection can reduce the expression of antimicrobial encoding genes promoted by inflammation. These findings suggest that controlling antimicrobial secretion in the mucus is a critical component of epithelial immunity. However, pathogens like H. pylori can overcome these defenses and survive in the mucosa.
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Peptídeos Antimicrobianos , Mucosa Gástrica , Helicobacter pylori , Inflamação , Muco , Humanos , Muco/metabolismo , Muco/microbiologia , Peptídeos Antimicrobianos/metabolismo , Mucosa Gástrica/microbiologia , Mucosa Gástrica/metabolismo , Mucosa Gástrica/imunologia , Inflamação/metabolismo , Células Epiteliais/microbiologia , Células Epiteliais/metabolismo , Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/metabolismo , Infecções por Helicobacter/imunologia , Estômago/microbiologia , Organoides/metabolismo , Organoides/microbiologiaRESUMO
CytoSorb is a hemoadsorptive column used to remove high concentrations of proinflammatory cytokines in septic shock. Data on CytoSorb application in acute-on-chronic liver failure (ACLF) is lacking. This retrospective observational study analyzed 21 ACLF patients admitted to ICUs at the Vienna General Hospital who received CytoSorb adsorber therapy between 2017 and 2023. Median ICU length of stay was 8 days (IQR: 3-13), the ICU survival rate was 23.8% (n = 5). Significant decreases in bilirubin (median peak: 20.7 mg/dL to median post-treatment: 10.8 mg/dL; - 47.8%; p < 0.001), procalcitonin (1.34 to 0.74 pg/mL; - 44.6%; p < 0.001), interleukin-6 (385 to 131 ng/mL; - 66.0%; p = 0.0182)-but also of platelets (72 to 31 G/L; - 56.9%; p = 0.0014) and fibrinogen (230 to 154 mg/dL; - 33.0%; p = 0.0297) were detected. ICU survivors had a trend towards a stronger relative decrease in bilirubin (- 76.1% vs. - 48.2%), procalcitonin (- 90.6% vs. - 23.5%), and IL-6 (- 54.6% vs. - 17.8%) upon CytoSorb treatment. Moreover, no serious CytoSorb-attributed complications were detected. In conclusion, use of CytoSorb adsorber in ACLF patients results in a significant decrease in bilirubin and proinflammatory cytokines, while platelets and fibrinogen were also lowered. Prospective trials are warranted to investigate the impact of CytoSorb on clinical outcomes of ACLF patients with high proinflammatory cytokine levels.
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Insuficiência Hepática Crônica Agudizada , Humanos , Insuficiência Hepática Crônica Agudizada/terapia , Insuficiência Hepática Crônica Agudizada/sangue , Masculino , Feminino , Pessoa de Meia-Idade , Estudos Retrospectivos , Idoso , Bilirrubina/sangue , Unidades de Terapia Intensiva , Adulto , Interleucina-6/sangue , Pró-Calcitonina/sangue , Tempo de InternaçãoRESUMO
Secondary infections in coronavirus disease 2019 (COVID-19) patients are difficult to distinguish from inflammation associated with COVID-19 and/or extracorporeal membrane oxygenation (ECMO). Therefore, highly specific and sensitive biomarkers are needed to identify patients in whom antimicrobial therapy can be safely withheld. In this prospective monocentric study, 66 COVID-19 patients admitted to the intensive care unit (ICU) for ECMO evaluation were included. A total of 46 (70%) patients with secondary infections were identified by using broad microbiological and virological panels and standardized diagnostic criteria. Various laboratory parameters including C-reactive protein (CRP), interleukin (IL)-6, procalcitonin (PCT), and IL-10 were determined at time of study inclusion. The best test performance for differentiating bacterial/fungal secondary infections and COVID-19 and/or ECMO associated inflammation was achieved by IL-10 (ROC-AUC 0.84) and a multivariant step-wise regression model including CRP, IL-6, PCT, and IL-10 (ROC-AUC 0.93). Data obtained in the present study highlights the use of IL-10 to differentiate secondary bacterial/fungal infections from COVID-19 and/or ECMO associated inflammation in severely ill COVID-19 patients.
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Neutrophils are critical to host defence, executing diverse strategies to perform their antimicrobial and regulatory functions. One tactic is the production of neutrophil extracellular traps (NETs). In response to certain stimuli, neutrophils decondense their lobulated nucleus and release chromatin into the extracellular space through a process called NETosis. However, NETosis, and the subsequent degradation of NETs, can become dysregulated. NETs are proposed to play a role in infectious as well as many non-infection related diseases including cancer, thrombosis, autoimmunity and neurological disease. Consequently, there is a need to develop specific tools for the study of these structures in disease contexts. In this study, we identified a NET-specific histone H3 cleavage event and harnessed this to develop a cleavage site-specific antibody for the detection of human NETs. By microscopy, this antibody distinguishes NETs from chromatin in purified and mixed cell samples. It also detects NETs in tissue sections. We propose this antibody as a new tool to detect and quantify NETs.
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Armadilhas Extracelulares , Trombose , Humanos , Armadilhas Extracelulares/metabolismo , Histonas/metabolismo , Neutrófilos , Trombose/metabolismo , Cromatina/metabolismoRESUMO
Rationale: Prostaglandin E1 (alprostadil; PGE1), in addition to low-dose unfractionated heparin, increases the biocompatibility of extracorporeal systems and enhances the efficacy of artificial organs without increasing bleeding risk. Objectives: We investigated the safety and efficacy of PGE1 in adults receiving venovenous extracorporeal membrane oxygenation (ECMO). Methods: This study was a randomized, double-blind, placebo-controlled phase II pilot trial at two medical intensive care units at the Medical University of Vienna, Austria. Adults with venovenous ECMO were randomly assigned to receive an intravenous infusion of 5 ng/kg/min PGE1 or placebo (0.9% saline) in addition to standard anticoagulation with unfractionated heparin. Measurements and Main Results: The primary outcome was the rate of transfused packed red blood cells per ECMO day. Secondary outcomes were the incidence of and time to clinically overt bleeding and thromboembolic events. A post hoc subgroup analysis included only patients with coronavirus disease (COVID-19). Between September 2016 and April 2021, of 133 screened patients, 50 patients were randomized, of whom 48 received the assigned study medication (24 per group). The transfusion rate was similar between groups (0.41 vs. 0.39; P = 0.733). PGE1 was associated with fewer thromboembolic events (7 vs. 16; P = 0.020) and longer thromboembolism-free time (hazard ratio [HR], 0.302; P = 0.01), fewer clinically overt bleeding events (2 vs. 11; P = 0.017), and longer bleeding-free time (HR, 0.213; P = 0.047). In patients with COVID-19 (n = 25), the HRs for clinically overt bleeding and thromboembolism were 0.276 (95% confidence interval, 0.035-2.186) and 0.521 (95% confidence interval, 0.149-1.825), respectively. Conclusions: Add-on treatment with PGE1 was safe but did not meet the primary endpoint of reducing the rate of red blood cell transfusions in patients receiving venovenous ECMO. Larger studies need to evaluate the safety and efficacy of additional PGE1 in ECMO. Clinical trial registered with EudraCT (2015-005014-30) and www.clinicaltrials.gov (NCT02895373).
Assuntos
COVID-19 , Oxigenação por Membrana Extracorpórea , Adulto , Alprostadil/uso terapêutico , Método Duplo-Cego , Hemorragia , Heparina/uso terapêutico , Humanos , Projetos PilotoRESUMO
OBJECTIVES: Extracorporeal membrane oxygenation provides large surface exposure to human blood leading to coagulation activation. Only limited clinical data are available on contact activation and coagulation factor XII activity in extracorporeal membrane oxygenation patients. DESIGN: Prospective cohort study. SETTING: Three medical ICUs at the Medical University of Vienna. PATIENTS: Adult patients receiving venovenous or venoarterial extracorporeal membrane oxygenation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the change in coagulation factor XII activity in response to extracorporeal membrane oxygenation. Secondary outcomes included the prevalence of reduced coagulation factor XII activity (< 60%) among patients receiving extracorporeal membrane oxygenation and association of coagulation factor XII activity with thromboembolic and bleeding complications. An exploratory endpoint was the association of coagulation factor XII activity and activated partial thromboplastin time in heparinase-treated samples in vitro. Fifty-one patients with a total of 117 samples were included in the study between July 2018 and February 2020. Fifty patients (98%) had reduced coagulation factor XII activity at any timepoint during extracorporeal membrane oxygenation. Median coagulation factor XII activity during extracorporeal membrane oxygenation treatment was 30% (interquartile range, 21.5-41%) and increased after discontinuation (p = 0.047). Patients with thromboembolic complications had higher median coagulation factor XII activity during extracorporeal membrane oxygenation (34% vs 23%; p = 0.023). The odds of a thromboembolic event increased by 200% per tertile of median coagulation factor XII activity (crude odds ratio, 3.034; 95% CI, 1.21-7.63). No association with bleeding was observed. In heparinase-treated samples, coagulation factor XII activity correlated well with activated partial thromboplastin time (r = -0.789; p = 0.007). CONCLUSIONS: We observed a high prevalence of reduced coagulation factor XII activity in adult patients on extracorporeal membrane oxygenation, which may confound activated partial thromboplastin time measurements and limit its clinical usefulness for monitoring and titrating anticoagulation with unfractionated heparin. Lower coagulation factor XII activity was associated with less thromboembolic complications, which may highlight the potential of coagulation factor XII to serve as a target for anticoagulation in extracorporeal membrane oxygenation.
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Oxigenação por Membrana Extracorpórea/efeitos adversos , Fator XII/biossíntese , Adulto , Áustria/epidemiologia , Estudos de Coortes , Oxigenação por Membrana Extracorpórea/métodos , Oxigenação por Membrana Extracorpórea/estatística & dados numéricos , Humanos , Tempo de Tromboplastina Parcial/métodos , Prevalência , Estudos Prospectivos , Estudos RetrospectivosRESUMO
Mycofactocin is a new class of peptide-derived redox cofactors present in a selected group of bacteria including Mycobacterium tuberculosis. Mycofactocin biosynthesis requires at least six genes, including mftD, encoding putative lactate dehydrogenase, which catalyzes the penultimate biosynthetic step. Cellular functions remained unknown until recent reports on the significance of mycofactocin in primary alcohol metabolism. Here, we show that mftD transcript levels were increased in hypoxia-adapted M. tuberculosis; however, mftD functionality was found likely dispensable for l-lactate metabolism. Targeted deletion of mftD reduced the survival of M. tuberculosis in in vitro and in vivo hypoxia models but increased the bacterial growth in glucose-containing broth as well as in the lungs and spleens, albeit modestly, of aerosol-infected C57BL/6J mice. The cause of this growth advantage remains unestablished; however, the mftD-deficient M. tuberculosis strain had reduced NAD(H)/NADP(H) levels and glucose-6-phosphate dehydrogenase activity with no impairment in phthiocerol dimycocerosate lipid synthesis. An ultrastructural examination of parental and mycofactocin biosynthesis gene mutants in M. tuberculosis, M. marinum, and M. smegmatis showed no altered cell morphology and size except the presence of outer membrane-bound fibril-like features only in a mutant subpopulation. A cell surface-protein analysis of M. smegmatis mycofactocin biosynthesis mutants with trypsin revealed differential abundances of a subset of proteins that are known to interact with mycofactocin and their homologs that can enhance protein aggregation or amyloid-like fibrils in riboflavin-starved eukaryotic cells. In sum, phenotypic analyses of the mutant strain implicate the significance of MftD/mycofactocin in M. tuberculosis growth and persistence in its host. IMPORTANCE Characterization of proteins with unknown functions is a critical research priority as the intracellular growth and metabolic state of Mycobacterium tuberculosis, the causative agent of tuberculosis, remain poorly understood. Mycofactocin is a peptide-derived redox cofactor present in almost all mycobacterial species; however, its functional relevance in M. tuberculosis pathogenesis and host survival has never been studied experimentally. In this study, we examine the phenotypes of an M. tuberculosis mutant strain lacking a key mycofactocin biosynthesis gene in in vitro and disease-relevant mouse models. Our results pinpoint the multifaceted role of mycofactocin in M. tuberculosis growth, hypoxia adaptation, glucose metabolism, and redox homeostasis. This evidence strongly implies that mycofactocin could fulfill specialized biochemical functions that increase the survival fitness of mycobacteria within their specific niche.
Assuntos
Adaptação Fisiológica , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Mycobacterium tuberculosis/enzimologia , Mycobacterium tuberculosis/crescimento & desenvolvimento , Peptídeos/metabolismo , Anaerobiose , Animais , Vias Biossintéticas , Feminino , Regulação Bacteriana da Expressão Gênica , Masculino , Camundongos Endogâmicos C57BL , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/metabolismo , Peptídeos/genéticaRESUMO
Extracorporeal membrane oxygenation (ECMO) has established as a cornerstone therapy in severe acute respiratory distress syndrome and refractory hemodynamic failure. As circuit integrity is crucial for adequate organ support, component failure may necessitate a system exchange. In this retrospective study, incidence and etiology of system exchanges during applications of venovenous, venoarterial ECMO, and extracorporeal CO2 removal were examined. Sixty-three (44.4%) of 142 patients were affected by one or more exchanges, totaling 105 replaced circuits. The predominant exchange reason was clotting (n = 20), followed by hemolysis (n = 19), systemic coagulation disorders (n = 13), reconfiguration (n = 13), impaired gas exchange (n = 10), mechanical complications (n = 8), bleeding (n = 6), failed weaning (n = 5), prophylactic exchange (n = 3), and undocumented/other (n = 8). Nineteen (18.1%) events were classified as acute and 70 (66.7%) events as elective exchanges. Patients with circuit exchanges more frequently underwent renal replacement therapy at ECMO initiation (49.2% vs. 29.1%; p = 0.023), had a longer ECMO treatment duration (18 vs. 7.5 days, p < 0.001), and lower hospital survival (29.5% vs. 57.1%; p = 0.002). Considering the high occurrence of coagulation complications, further optimization of coagulation management is deemed necessary.
Assuntos
Oxigenação por Membrana Extracorpórea , Coagulação Sanguínea , Oxigenação por Membrana Extracorpórea/efeitos adversos , Humanos , Incidência , Síndrome do Desconforto Respiratório , Estudos RetrospectivosRESUMO
BACKGROUND & AIMS: The homeostasis of the gastrointestinal epithelium relies on cell regeneration and differentiation into distinct lineages organized inside glands and crypts. Regeneration depends on Wnt/ß-catenin pathway activation, but to understand homeostasis and its dysregulation in disease, we need to identify the signaling microenvironment governing cell differentiation. By using gastric glands as a model, we have identified the signals inducing differentiation of surface mucus-, zymogen-, and gastric acid-producing cells. METHODS: We generated mucosoid cultures from the human stomach and exposed them to different growth factors to obtain cells with features of differentiated foveolar, chief, and parietal cells. We localized the source of the growth factors in the tissue of origin. RESULTS: We show that epidermal growth factor is the major fate determinant distinguishing the surface and inner part of human gastric glands. In combination with bone morphogenetic factor/Noggin signals, epidermal growth factor controls the differentiation of foveolar cells vs parietal or chief cells. We also show that epidermal growth factor is likely to underlie alteration of the gastric mucosa in the precancerous condition atrophic gastritis. CONCLUSIONS: Use of our recently established mucosoid cultures in combination with analysis of the tissue of origin provided a robust strategy to understand differentiation and patterning of human tissue and allowed us to draw a new, detailed map of the signaling microenvironment in the human gastric glands.
Assuntos
Padronização Corporal/efeitos dos fármacos , Proteína Morfogenética Óssea 4/farmacologia , Diferenciação Celular/efeitos dos fármacos , Fator de Crescimento Epidérmico/farmacologia , Células Epiteliais/efeitos dos fármacos , Mucosa Gástrica/efeitos dos fármacos , Proteínas de Transporte/farmacologia , Linhagem da Célula , Células Cultivadas , Microambiente Celular , Celulas Principais Gástricas/efeitos dos fármacos , Celulas Principais Gástricas/metabolismo , Celulas Principais Gástricas/ultraestrutura , Células Epiteliais/metabolismo , Células Epiteliais/ultraestrutura , Mucosa Gástrica/metabolismo , Mucosa Gástrica/ultraestrutura , Gastrite Atrófica/metabolismo , Gastrite Atrófica/patologia , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Organoides , Células Parietais Gástricas/efeitos dos fármacos , Células Parietais Gástricas/metabolismo , Células Parietais Gástricas/ultraestrutura , Via de Sinalização WntRESUMO
The gastric pathogen Helicobacter pylori activates the NF-κB pathway in human epithelial cells via the recently discovered α-kinase 1 TRAF-interacting protein with forkhead-associated domain (TIFA) axis. We and others showed that this pathway can be triggered by heptose 1,7-bisphosphate (HBP), an LPS intermediate produced in gram-negative bacteria that represents a new pathogen-associated molecular pattern (PAMP). Here, we report that our attempts to identify HBP in lysates of H. pylori revealed surprisingly low amounts, failing to explain NF-κB activation. Instead, we identified ADP-glycero-ß-D-manno-heptose (ADP heptose), a derivative of HBP, as the predominant PAMP in lysates of H. pylori and other gram-negative bacteria. ADP heptose exhibits significantly higher activity than HBP, and cells specifically sensed the presence of the ß-form, even when the compound was added extracellularly. The data lead us to conclude that ADP heptose not only constitutes the key PAMP responsible for H. pylori-induced NF-κB activation in epithelial cells, but it acts as a general gram-negative bacterial PAMP.-Pfannkuch, L., Hurwitz, R., Traulsen, J., Sigulla, J., Poeschke, M., Matzner, L., Kosma, P., Schmid, M., Meyer, T. F. ADP heptose, a novel pathogen-associated molecular pattern identified in Helicobacter pylori.
Assuntos
Açúcares de Adenosina Difosfato/metabolismo , Helicobacter pylori/metabolismo , Heptoses/metabolismo , Moléculas com Motivos Associados a Patógenos/metabolismo , Açúcares de Adenosina Difosfato/química , Açúcares de Adenosina Difosfato/imunologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Linhagem Celular , Células Epiteliais/imunologia , Células Epiteliais/metabolismo , Células Epiteliais/microbiologia , Deleção de Genes , Genes Bacterianos , Glicosiltransferases/genética , Glicosiltransferases/metabolismo , Helicobacter pylori/genética , Helicobacter pylori/imunologia , Heptoses/química , Heptoses/imunologia , Humanos , Imunidade Inata , NF-kappa B/metabolismo , Moléculas com Motivos Associados a Patógenos/química , Moléculas com Motivos Associados a Patógenos/imunologia , Transdução de Sinais , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrometria de Massas em TandemRESUMO
OBJECTIVE: Patients on extracorporeal membrane oxygenation are frequently in need for sedation. Use of propofol has been associated with impaired oxygenator function due to adsorption to the membrane as well as lipid load. The aim of our retrospective analysis was to compare two different sedation regimens containing either propofol or midazolam with respect to oxygenator running time. METHODS: Midazolam was used in 73 patients whereas propofol was used in 49 patients, respectively. In the propofol group, veno-arterial-extracorporeal membrane oxygenation was used predominantly (84%), while veno-venous-extracorporeal membrane oxygenation was used more often in the midazolam group (64%). RESULTS: Oxygenator running time until first exchange was 7 days in both groups ( p = 0.759). No statistically significant differences could be observed between the subgroup of patients receiving lipid-free (n = 24) and lipid-containing (n = 31) parenteral nutrition, respectively. Laboratory parameters like triglycerides, free hemoglobin, fibrinogen, platelets, and activated partial thromboplastin time were not significantly different between both sedation regimens ( p = 0.462, p = 0.489, p = 0.960, p = 0.134, and p = 0.843) and were not associated with oxygenator running time. CONCLUSION: The use of propofol as sedative seems suitable in patients undergoing extracorporeal membrane oxygenation therapy.
Assuntos
Sedação Consciente/métodos , Oxigenação por Membrana Extracorpórea , Midazolam , Oxigenadores , Adulto , Idoso , Falha de Equipamento , Oxigenação por Membrana Extracorpórea/efeitos adversos , Oxigenação por Membrana Extracorpórea/instrumentação , Oxigenação por Membrana Extracorpórea/métodos , Feminino , Humanos , Hipnóticos e Sedativos/administração & dosagem , Masculino , Midazolam/administração & dosagem , Midazolam/efeitos adversos , Pessoa de Meia-Idade , Propofol/administração & dosagem , Propofol/efeitos adversos , Estudos RetrospectivosRESUMO
OBJECTIVE: Helicobacter pylori causes life-long colonisation of the gastric mucosa, leading to chronic inflammation with increased risk of gastric cancer. Research on the pathogenesis of this infection would strongly benefit from an authentic human in vitro model. DESIGN: Antrum-derived gastric glands from surgery specimens served to establish polarised epithelial monolayers via a transient air-liquid interface culture stage to study cross-talk with H. pylori and the adjacent stroma. RESULTS: The resulting 'mucosoid cultures', so named because they recapitulate key characteristics of the gastric mucosa, represent normal stem cell-driven cultures that can be passaged for months. These highly polarised columnar epithelial layers encompass the various gastric antral cell types and secrete mucus at the apical surface. By default, they differentiate towards a foveolar, MUC5AC-producing phenotype, whereas Wnt signalling stimulates proliferation of MUC6-producing cells and preserves stemness-reminiscent of the gland base. Stromal cells from the lamina propria secrete Wnt inhibitors, antagonising stem-cell niche signalling and inducing differentiation. On infection with H. pylori, a strong inflammatory response is induced preferentially in the undifferentiated basal cell phenotype. Infection of cultures for several weeks produces foci of viable bacteria and a persistent inflammatory condition, while the secreted mucus establishes a barrier that only few bacteria manage to overcome. CONCLUSION: Gastric mucosoid cultures faithfully reproduce the features of normal human gastric epithelium, enabling new approaches for investigating the interaction of H. pylori with the epithelial surface and the cross-talk with the basolateral stromal compartment. Our observations provide striking insights in the regulatory circuits of inflammation and defence.
Assuntos
Mucosa Gástrica/microbiologia , Infecções por Helicobacter/patologia , Helicobacter pylori/fisiologia , Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Células Epiteliais/metabolismo , Células Epiteliais/microbiologia , Células Epiteliais/patologia , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patologia , Infecções por Helicobacter/metabolismo , Homeostase/fisiologia , Interações entre Hospedeiro e Microrganismos/fisiologia , Humanos , Muco/metabolismo , Antro Pilórico/metabolismo , Antro Pilórico/microbiologia , Antro Pilórico/patologia , Nicho de Células-Tronco , Células Estromais/fisiologia , Técnicas de Cultura de Tecidos/métodosRESUMO
After publication, the author noticed that Table 2 was incorrectly formatted for the final PDF despite being correct in earlier proofs. The table was correct in the HTML version of the article. The EJCN apologizes for the inadvertent error in the formatting of Table 2. The corrected version is uploaded and should be read in conjunction with the original paper. Any inconvenience to the author and readership is regretted.
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Late bilinguals who spend (part of) their adult lives in an environment where a language other than the one they learned in childhood is spoken typically experience a range of language development phenomena. Most obviously, they will acquire some level of receptive and/or productive knowledge of the new, or second, language (L2). How basic or advanced that level will be is determined by a range of environmental, experiential, attitudinal and individual factors. Secondly, they will most likely find the knowledge of their native language (L1) beginning to diverge from that of monolingual speakers in their country of origin, a process known as language attrition. In the course of this developmental process, some L2 skills may eventually match or even overtake the corresponding skill in the L1. This shift in the balance between L1 and L2 is the focus of investigations of language dominance. The present study explores language dominance in four migrant populations (Germans in the Netherlands and Canada, Turks and Moroccans in the Netherlands). Investigating both the development of formal/controlled skills and more automatic aspects of lexical access and fluency, we aim to attain an understanding of how extralinguistic factors contribute to the development of both languages. We argue that an integrated perspective can contribute more profound insights into the predictors of this complex process of bilingual development. In particular, our findings show that statistical models based on linear relationships fall short of capturing the full picture. We propose an alternative method of analysing data, namely discriminant function analysis, based on a categorisation of the populations, and demonstrate how this can enhance our understanding. Our findings suggest that different aspects of the bilingual experience contribute differently to language development, regardless of language combination and type of skill measured. Contrary to what previous research suggests, measures relating to the intensity of informal use of both the L1 and the L2 in daily life are important in determining whether someone is a good or a poor L1 maintainer, while high vs. low success in acquisition appears to be predominantly associated with personal factors such as educational level.
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BACKGROUND/OBJECTIVES: Hyperglycemia is common in critically ill patients and associated with increased mortality. It has been suggested that different nutrition formulas may beneficially influence glucose levels in surgical intensive care patients. In this prospective randomized clinical cohort study we investigated glucose homeostasis in response to different enteral nutrition formulas in medical critically ill patients. SUBJECTS/METHODS: 60 medical critically ill patients were randomized to receive continuous fat-based (group A, n = 30) or glucose-based enteral nutrition (group B, n = 30) for seven days. Indirect calorimetry was performed to determine energy demand at baseline and on days 3 and 7. Glucose levels and area under the curve (AUC), insulin demand, glucose variability, and calorie and substrate intake per 24 h were assessed for 7 days. RESULTS: Over the course of 7 days patients had similar average daily glucose (p = 0.655), glucose AUC (A: 758 (641-829) mg/dl/day vs B: 780 (733-845) mg/dl/day, p = 0.283), similar overall insulin demand (A: 153.5 (45.3-281.5) IE vs B: 167.9 (82.3-283.8) IE, p = 0.525), and received similar amounts of enteral nutrition per 24 h. Resting energy expenditure was similar at baseline (A: 1556 (1227-1808) kcal/day vs B: 1563 (1306-1789) kcal/day, p = 0.882) but energy expenditure increased substantially over time in group A (p < 0.0001), but not in group B (p = 0.097). CONCLUSION: Fat-based and glucose-based EN influence glucose homeostasis and insulin demand similarly, yet diet-induced thermogenesis was substantially higher in critically ill patients receiving fat-based enteral nutrition.
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Glicemia/fisiologia , Estado Terminal , Nutrição Enteral , Alimentos Formulados , Termogênese/fisiologia , Adulto , Idoso , Estado Terminal/epidemiologia , Estado Terminal/terapia , Nutrição Enteral/efeitos adversos , Nutrição Enteral/métodos , Nutrição Enteral/estatística & dados numéricos , Feminino , Alimentos Formulados/efeitos adversos , Alimentos Formulados/estatística & dados numéricos , Hospitalização , Humanos , Masculino , Pessoa de Meia-Idade , Estado Nutricional , Estudos ProspectivosRESUMO
Only limited data are available regarding the treatment of critically ill patients with clopidogrel. This trial investigated the effects and the drug concentrations of the cytochrome P450 (CYP450) activated prodrug clopidogrel (n = 43) and the half-life of the similarly metabolized pantoprazole (n = 16) in critically ill patients. ADP-induced aggregometry in whole blood classified 74% (95% confidence intervals 59-87%) of critically ill patients as poor responders (n = 43), and 65% (49-79%) responded poorly according to the vasodilator-stimulated phosphoprotein phosphorylation (VASP-P) assay. Although the plasma levels of clopidogrel active metabolite normally exceed the inactive prodrug â¼30-fold, the parent drug levels even exceeded those of the metabolite 2-fold in critically ill patients. The half-life of pantoprazole was several-fold longer in these patients compared with reference populations. The inverse ratio of prodrug/active metabolite indicates insufficient metabolization of clopidogrel, which is independently confirmed by the â¼5-fold increase in half-life of pantoprazole. Thus, high-risk patients may benefit from treatment with alternative platelet inhibitors.
Assuntos
Plaquetas/efeitos dos fármacos , Clopidogrel/farmacocinética , Estado Terminal , Pantoprazol/farmacocinética , Inibidores da Agregação Plaquetária/farmacocinética , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Bomba de Prótons/farmacocinética , Ativação Metabólica , Idoso , Áustria , Biomarcadores/sangue , Plaquetas/metabolismo , Moléculas de Adesão Celular/sangue , Clopidogrel/administração & dosagem , Clopidogrel/efeitos adversos , Clopidogrel/sangue , Citocromo P-450 CYP2C19/genética , Citocromo P-450 CYP2C19/metabolismo , Regulação para Baixo , Monitoramento de Medicamentos/métodos , Resistência a Medicamentos , Feminino , Meia-Vida , Humanos , Masculino , Proteínas dos Microfilamentos/sangue , Pessoa de Meia-Idade , Pantoprazol/administração & dosagem , Pantoprazol/efeitos adversos , Pantoprazol/sangue , Fosfoproteínas/sangue , Inibidores da Agregação Plaquetária/administração & dosagem , Inibidores da Agregação Plaquetária/efeitos adversos , Inibidores da Agregação Plaquetária/sangue , Testes de Função Plaquetária , Inibidores da Bomba de Prótons/administração & dosagem , Inibidores da Bomba de Prótons/efeitos adversos , Inibidores da Bomba de Prótons/sangueRESUMO
Activation of transcription factor NF-κB is a hallmark of infection with the gastric pathogen Helicobacter pylori, associated with inflammation and carcinogenesis. Genome-wide RNAi screening revealed numerous host factors involved in H. pylori-, but not IL-1ß- and TNF-α-dependent NF-κB regulation. Pathway analysis including CRISPR/Cas9-knockout and recombinant protein technology, immunofluorescence microscopy, immunoblotting, mass spectrometry, and mutant H. pylori strains identified the H. pylori metabolite D-glycero-ß-D-manno-heptose 1,7-bisphosphate (ßHBP) as a cagPAI type IV secretion system (T4SS)-dependent effector of NF-κB activation in infected cells. Upon pathogen-host cell contact, TIFA forms large complexes (TIFAsomes) including interacting host factors, such as TRAF2. NF-κB activation, TIFA phosphorylation, and TIFAsome formation depend on a functional ALPK1 kinase, highlighting the ALPK1-TIFA axis as a core innate immune pathway. ALPK1-TIFA-mediated NF-κB activation was independent of CagA protein translocation, indicating that CagA translocation and HBP delivery to host cells are distinct features of the pathogen's T4SS.
Assuntos
Transdução de Sinais/fisiologia , Sistemas de Secreção Tipo IV/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Sistemas CRISPR-Cas/genética , Sistemas CRISPR-Cas/fisiologia , Infecções por Helicobacter/imunologia , Infecções por Helicobacter/metabolismo , Helicobacter pylori/imunologia , Helicobacter pylori/patogenicidade , Humanos , Imunidade Inata/genética , Imunidade Inata/fisiologia , Microscopia de Fluorescência , NF-kappa B/metabolismo , Moléculas com Motivos Associados a Patógenos/metabolismo , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Interferência de RNA , Transdução de Sinais/genética , Fator de Necrose Tumoral alfa/metabolismo , Sistemas de Secreção Tipo IV/genéticaRESUMO
Scientists have identified the impact of angiogenesis on tumor growth and survival. Among other efficient drugs, several small-molecule tyrosine kinase inhibitors (TKIs) targeting the vascular endothelial growth factor receptor (VEGFR) have been developed and have already been integrated into the treatment of various advanced malignancies. This review provides a compilation of current knowledge on the pharmacokinetic aspects of all VEGFR-TKIs already approved by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) and of those still under investigation. Additional information on substance metabolism, potential for drug-drug interactions (DDIs), and the need for dose adaptation in patients with predominant renal and/or hepatic impairment has been included. All TKIs introduced in this review were administered orally, allowing for easy drug handling for healthcare professionals and patients. For almost all substances, the maximum plasma concentrations were reached within a short period of time. The majority of the substances showed a high plasma protein binding and their excretion occurred via the feces and, to a lesser extent, via the urine. In most cases, dose adaptation in patients with mild to moderate renal or hepatic impairment is not recommended. Cytochrome P450 (CYP) 3A4 was found to play a crucial role in the drug metabolic processes of many compounds. In order to prevent unwanted DDIs, co-administration of VEGFR TKIs together with CYP3A4 inhibitors or inducers should be avoided. Throughout all TKIs, the data indicate high inter-individual variability. The causes of this are still unclear and require further research to allow for individualization of treatment regimens.
Assuntos
Citocromo P-450 CYP3A/metabolismo , Inibidores de Proteínas Quinases/farmacocinética , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Administração Oral , Interações Medicamentosas , Fezes/química , Humanos , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/urinaRESUMO
In this study we investigate the effect of age of acquisition (AoA) on grammatical processing in second language learners as measured by event-related brain potentials (ERPs). We compare a traditional analysis involving the calculation of averages across a certain time window of the ERP waveform, analyzed with categorical groups (early vs. late), with a generalized additive modeling analysis, which allows us to take into account the full range of variability in both AoA and time. Sixty-six Slavic advanced learners of German listened to German sentences with correct and incorrect use of non-finite verbs and grammatical gender agreement. We show that the ERP signal depends on the AoA of the learner, as well as on the regularity of the structure under investigation. For gender agreement, a gradual change in processing strategies can be shown that varies by AoA, with younger learners showing a P600 and older learners showing a posterior negativity. For verb agreement, all learners show a P600 effect, irrespective of AoA. Based on their behavioral responses in an offline grammaticality judgment task, we argue that the late learners resort to computationally less efficient processing strategies when confronted with (lexically determined) syntactic constructions different from the L1. In addition, this study highlights the insights the explicit focus on the time course of the ERP signal in our analysis framework can offer compared to the traditional analysis.
Assuntos
Encéfalo/fisiologia , Compreensão/fisiologia , Potenciais Evocados , Adulto , Fatores Etários , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Multilinguismo , Vocabulário , Adulto JovemRESUMO
Bilingual and monolingual language processing differ, presumably because of constant parallel activation of both languages in bilinguals. We attempt to isolate the effects of parallel activation in a group of German first-language (L1) attriters, who have grown up as monolingual natives before emigrating to an L2 environment. We hypothesized that prolonged immersion will lead to changes in the processing of morphosyntactic violations. Two types of constructions were presented as stimuli in an event-related potential experiment: (1) verb form combinations (auxiliaries+past participles and modals+infinitives) and (2) determiner-noun combinations marked for grammatical gender. L1 attriters showed the same response to violations of gender agreement as monolingual controls (i.e. a significant P600 effect strongest over posterior electrodes). Incorrect verb form combinations also elicited a significant posterior P600 effect in both groups. In attriters, however, there was an additional posterior N400 effect for this type of violation. Such biphasic patterns have been found before in L1 and L2 speakers of English and might reflect the influence of this language. Generally, we interpret our results as evidence for the stability of the deeply entrenched L1 system, even in the face of L2 interference.