In-hospital mortality after prehospital endotracheal intubation versus alternative methods of airway management in trauma patients. A cohort study from the TraumaRegister DGU®.

PURPOSE: Prehospital airway management in trauma is a key component of care and is associated with particular risks. Endotracheal intubation (ETI) is the gold standard, while extraglottic airway devices (EGAs) are recommended alternatives. There is limited evidence comparing their effectiveness. In this retrospective analysis from the TraumaRegister DGU®, we compared ETI with EGA in prehospital airway management regarding in-hospital mortality in patients with trauma. METHODS: We included cases only from German hospitals with a minimum Abbreviated Injury Scale score ≥ 2 and age ≥ 16 years. All patients without prehospital airway protection were excluded. We performed a multivariate logistic regression to adjust with the outcome measure of hospital mortality. RESULTS: We included n = 10,408 cases of whom 92.5% received ETI and 7.5% EGA. The mean injury severity score was higher in the ETI group (28.8 ± 14.2) than in the EGA group (26.3 ± 14.2), and in-hospital mortality was comparable: ETI 33.0%; EGA 30.7% (27.5 to 33.9). After conducting logistic regression, the odds ratio for mortality in the ETI group was 1.091 (0.87 to 1.37). The standardized mortality ratio was 1.04 (1.01 to 1.07) in the ETI group and 1.1 (1.02 to 1.26) in the EGA group. CONCLUSIONS: There was no significant difference in mortality rates between the use of ETI or EGA, or the ratio of expected versus observed mortality when using ETI.

How Would I Treat My Own Thoracoabdominal Aortic Aneurysm: Perioperative Considerations From the Anesthesiologist Perspective.

A thoracoabdominal aortic aneurysm (TAAA) can be potentially life-threatening due to its associated risk of rupture. Thoracoabdominal aortic aneurysm repair, performed as endovascular repair and/or open surgery, is the recommended therapy of choice. Hemodynamic instability, severe blood loss, and spinal cord or cerebral ischemia are some potential hazards the perioperative team has to face during these procedures. Therefore, preoperative risk assessment and intraoperative anesthesia management addressing these potential hazards are essential to improving patients' outcomes. Based on a presented index case, an overview focusing on anesthetic measures to identify perioperatively and manage these risks in TAAA repair is provided.

Influence of timing of Levosimendan administration on outcomes in cardiac surgery.

Purpose: Though a subgroup analysis has shown improved survival for patients suffering severely reduced ventricular function undergoing coronary artery bypass grafting, RCTs were not able to demonstrate overall beneficial effects of perioperative Levosimendan in cardiac surgery. This might be due to Levosimendan's pharmacokinetics reaching a steady-state concentration only 4-8 h after administration. Thus, this study now analysed the influence of timing of Levosimendan administration on perioperative outcome in cardiac surgery patients preoperatively presenting with severely reduced ventricular function and therefore considered at high-risk for intra- or postoperative low cardiac output syndrome. We hypothesized that prolonged preoperative Levosimendan administration ("preconditioning") would reduce mortality. Methods: All adult patients undergoing cardiac surgery between 2006 and 2018 perioperatively receiving Levosimendan were included in this retrospective, observational cohort study (n = 498). Patients were stratified into 3 groups: Levosimendan started on the day prior to surgery ("preop"), Levosimendan started on the day of surgery ("intraop") or post ICU admission ("postop"). After propensity score matching (PSM) was performed, outcomes defined according to proposed standard definitions for perioperative outcome research were compared between groups. Results: After PSM, there were no significant differences in patients' characteristics, comorbidities and type/priority of surgery between groups. Compared to intraop or postop Levosimendan treatment, preop treated patients had significantly lower in-hospital-mortality (preop vs. intraop. vs. postop = 16,7% vs. 33,3% vs. 42,3%), duration of mechanical ventilation and rate of continuous renal replacement therapy. Conclusions: Prolonged preoperative treatment with Levosimendan of cardiac surgery patients preoperatively presenting with severely reduced left ventricular function might be beneficial in terms of postoperative outcome. Our results are in line with recent experts' recommendations concerning the prolonged perioperative use of Levosimendan. We strongly recommend that future randomized trials include this "preconditioning" treatment as an experimental arm.

Identification of Perioperative Procedural and Hemodynamic Risk Factors for Developing Colonic Ischemia after Ruptured Infrarenal Abdominal Aortic Aneurysm Surgery: A Single-Centre Retrospective Cohort Study.

(1) Background: This retrospective study evaluated perioperative and intensive care unit (ICU) variables to predict colonic ischemia (CI) after infrarenal ruptured abdominal aortic aneurysm (RAAA) surgery. (2) Materials and Methods: We retrospectively analyzed the data of the patients treated for infrarenal RAAA from January 2011 to December 2020 in our hospital. (3) Results: A total of 135 (82% male) patients were admitted to ICU after treatment of infrarenal RAAA. The median age of all patients was 75 years (IQR 68-81 years). Of those, 24 (18%) patients developed CI, including 22 (92%) cases within the first three postoperative days. CI was found more often after open repair compared to endovascular treatment (22% vs. 5%, p = 0.021). Laboratory findings in the first seven PODs revealed statistically significant differences between CI and non-CI patients for serum lactate, minimum pH, serum bicarbonate, and platelet count. Norepinephrine (NE) was used in 92 (68%) patients during ICU stay. The highest daily dose of norepinephrine was administered to CI patients at POD1. Multivariable analysis revealed that NE > 64 µg/kg (RD 0.40, 95% CI: 0.25-0.55, p < 0.001), operating time ≥ 200 min (RD 0.18, 95% CI: 0.05-0.31, p = 0.042), and pH < 7.3 (RD 0.21, 95% CI: 0.07-0.35, p = 0.019), significantly predicted the development of CI. A total of 23 (17%) patients died during the hospital stay, including 8 (33%) patients from the CI group and 15 (7%) from the non-CI group (p = 0.032). (4) Conclusions: CI after RAAA is a sever complication occurring most frequently within the first 3 postoperative days. Our study identified many surrogate markers associated with colonic ischemia after aortic RAAA, including norepinephrine dose > 64 µg/kg, operating time ≥ 200 min, and PH < 7.3. Future studies are needed to support these results.

The transcriptional co-activator Yap1 promotes adult hippocampal neural stem cell activation.

Most adult hippocampal neural stem cells (NSCs) remain quiescent, with only a minor portion undergoing active proliferation and neurogenesis. The molecular mechanisms that trigger the transition from quiescence to activation are still poorly understood. Here, we found the activity of the transcriptional co-activator Yap1 to be enriched in active NSCs. Genetic deletion of Yap1 led to a significant reduction in the relative proportion of active NSCs, supporting a physiological role of Yap1 in regulating the transition from quiescence to activation. Overexpression of wild-type Yap1 in adult NSCs did not induce NSC activation, suggesting tight upstream control mechanisms, but overexpression of a gain-of-function mutant (Yap1-5SA) elicited cell cycle entry in NSCs and hilar astrocytes. Consistent with a role of Yap1 in NSC activation, single cell RNA sequencing revealed a partial induction of an activated NSC gene expression program. Furthermore, Yap1-5SA expression also induced expression of Taz and other key components of the Yap/Taz regulon that were previously identified in glioblastoma stem cell-like cells. Consequently, dysregulated Yap1 activity led to repression of hippocampal neurogenesis, aberrant cell differentiation, and partial acquisition of a glioblastoma stem cell-like signature.

Intraoperative Beat-to-Beat Pulse Transit Time (PTT) Monitoring via Non-Invasive Piezoelectric/Piezocapacitive Peripheral Sensors Can Predict Changes in Invasively Acquired Blood Pressure in High-Risk Surgical Patients.

BACKGROUND: Non-invasive tracking of beat-to-beat pulse transit time (PTT) via piezoelectric/piezocapacitive sensors (PES/PCS) may expand perioperative hemodynamic monitoring. This study evaluated the ability for PTT via PES/PCS to correlate with systolic, diastolic, and mean invasive blood pressure (SBPIBP, DBPIBP, and MAPIBP, respectively) and to detect SBPIBP fluctuations. METHODS: PES/PCS and IBP measurements were performed in 20 patients undergoing abdominal, urological, and cardiac surgery. A Pearson's correlation analysis (r) between 1/PTT and IBP was performed. The predictive ability of 1/PTT with changes in SBPIBP was determined by area under the curve (reported as AUC, sensitivity, specificity). RESULTS: Significant correlations between 1/PTT and SBPIBP were found for PES (r = 0.64) and PCS (r = 0.55) (p < 0.01), as well as MAPIBP/DBPIBP for PES (r = 0.6/0.55) and PCS (r = 0.5/0.45) (p < 0.05). A 7% decrease in 1/PTTPES predicted a 30% SBPIBP decrease (0.82, 0.76, 0.76), while a 5.6% increase predicted a 30% SBPIBP increase (0.75, 0.7, 0.68). A 6.6% decrease in 1/PTTPCS detected a 30% SBPIBP decrease (0.81, 0.72, 0.8), while a 4.8% 1/PTTPCS increase detected a 30% SBPIBP increase (0.73, 0.64, 0.68). CONCLUSIONS: Non-invasive beat-to-beat PTT via PES/PCS demonstrated significant correlations with IBP and detected significant changes in SBPIBP. Thus, PES/PCS as a novel sensor technology may augment intraoperative hemodynamic monitoring during major surgery.

Dexmedetomidine Sedation Combined With Remifentanil in MitraClip Procedures is Feasible and Improves Hemodynamics.

OBJECTIVES: The objective of the study was to compare the overall feasibility, respiratory and hemodynamic stability, as well as process times of a dexmedetomidine-based sedative regimen compared with general anesthesia among patients undergoing MitraClip procedures. DESIGN: A retrospective cohort study. SETTING: A single tertiary care university center. PARTICIPANTS: The study included 79 patients. INTERVENTIONS: Dexmedetomidine sedation versus general anesthesia. MEASUREMENTS AND MAIN RESULTS: Seventy-nine MitraClip procedures in dexmedetomidine/remifentanil conscious sedation (DCS, n = 26) or general anesthesia (GA, n = 53), performed between 2018 and 2020 at Charité - Universitätsmedizin Berlin, were analyzed retrospectively. Patients' median age was 81 years in both groups without differences in preinterventional EuroScore I (DCS 6 [5; 8], GA 7 [6; 8]) or systolic function (left ventricular ejection fraction: DCS 50% [32; 60] v. GA 50% [36; 60]; tricuspid annular plane systolic excursion: DCS 19 mm [16; 22] v GA 19 mm [15; 22]). During MitraClip procedures, respiratory parameters revealed no differences between groups, whereas patients under DCS showed higher mean arterial pressures (DCS 64 mmHg [59; 74] v GA 58 mmHg [53; 66]) and needed less norepinephrine (DCS 0.0µg/kg/min [0.0; 0.2] v GA 0.08 µg/kg/min [0.05; 0.15]). Emergence from both anesthesia regimens to readiness for intensive care unit transfer was faster in DCS (8 min [4; 18] v GA 16 min [11; 23]); however, total process time was comparable between groups (DCS 128 min [104; 155] v GA 142 min [117; 190]). Two patients required a switch from DCS to GA due to oral bleeding or prolonged procedure time. Both were excluded from the analysis. There was no switch to open surgery and no differences in postoperative complications between DCS and GA. CONCLUSION: Dexmedetomidine/remifentanil sedation appears to be feasible and a safe option for MitraClip procedures, and provides better hemodynamic stability with faster emergence times compared with general anesthesia.

Effect of perioperative levosimendan administration on postoperative N-terminal pro-B-type natriuretic peptide concentration in patients with increased cardiovascular risk factors undergoing non-cardiac surgery: protocol for the double-blind, randomised, placebo-controlled IMPROVE trial.

INTRODUCTION: Elevated N-terminal pro-brain natriuretic peptide (NT-pro-BNP) after non-cardiac surgery is a strong predictor for cardiovascular complications and reflects increased myocardial strain. NT-pro-BNP concentrations significantly rise after non-cardiac surgery within the first 3 days. Levosimendan is a potent inotropic drug that increases calcium sensitivity to cardiac myocytes, which results in improved cardiac contractility that last for approximately 7 days. Thus, we will test the effect of a pre-emptive perioperative administration of levosimendan on postoperative NT-pro-BNP concentration as compared with the administration of a placebo in patients undergoing moderate-risk to high-risk major abdominal surgery. METHODS AND ANALYSIS: We will conduct a double-blinded prospective randomised trial at the Medical University of Vienna, Vienna, Austria (and potentially a second centre in Germany), including 230 patients at-risk for cardiovascular complications undergoing moderate- to high-risk major abdominal surgery. Patients will be randomly assigned to receive a single dose of 12.5 mg levosimendan versus placebo after induction of anaesthesia. The primary outcome will be the postoperative maximum NT-pro-BNP concentration between both group within the first three postoperative days. Our secondary outcomes will be the incidence of myocardial ischaemia, myocardial injury after non-cardiac surgery and a composite of myocardial infarction and death within 30 days and 1 year after surgery between both groups. Our further secondary outcome will be stratification of NT-pro-BNP values according to previously thresholds to predict mortality of myocardial infarction after surgery. ETHICS AND DISSEMINATION: The study was approved by the Ethics Committee of the Medical University of Vienna on 14 July 2020 (EK 2187/2019). Written informed consent will be obtained from all patients a day before surgery. Results of this study will be submitted for publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT04329624.

Isolated Ruptured Paravisceral Penetrating Aortic Ulcers.

BACKGROUND: The goal of this study is to investigate the clinical presentation, treatment options, and outcomes of the patients with isolated ruptured paravisceral penetrating aortic ulcers (PV-PAU). METHODS: All patients presenting with acute aortic syndrome from 2015 to 2020 were screened, of which patients with isolated ruptured PV-PAU were included in this retrospective study. Study endpoints were the assessment of treatment options, technical success, and clinical outcome. Outcome measures included major perioperative complications and mortality. RESULTS: Sixteen patients (11 men; median age 68; IQR 60 - 75 years) presented with isolated ruptured PV-PAU were included in this study. The median follow-up was 25 months (range 1 - 51). Ruptured PV-PAUs represented 12.3% of the ruptured aortic aneurysms in all locations. PV-PAUs were found in segment A (n = 8, 50%), segment B (n = 5, 31%), and segment C (n = 3, 19%). PV-PAUs showed a mean protrusion distance of 27±10 mm, a mean neck diameter of 21 ± 7 mm, and maximal aortic diameter of 50 ± 11 mm. Five patients (31%) showed hemodynamic instability on admission and needed intense fluid resuscitation. Of those, 2 patients needed urgent laparotomy with a fast transabdominal supraceliac aortic clamping, one needed an aortic balloon occlusion to obtain rapid aortic control. The open aortic repair was the most frequently performed surgery (11/16, 69%), followed by hybrid procedures (3/16) and parallel graft chimney technique (2/16). Two patients died during the follow-up, calculating for in-hospital and 1-year mortality rates of 6 - 12%, respectively. The postoperative morbidity rate was 31%. Postoperative complications included acute renal failure (31%), pneumonia (25%), and 1case of ischemic colitis (6%). No spinal cord ischemia was reported. CONCLUSIONS: Ruptured PV-PAU is a rare and challenging diagnostic and therapeutic entity. Open aortic repair seems to be a reliable option in treating patients with isolated ruptured PV-PAUs. Hybrid procedures and parallel stent-graft techniques can only be used in selected patients.

High Central Venous Pressure after Cardiac Surgery Might Depict Hemodynamic Deterioration Associated with Increased Morbidity and Mortality.

BACKGROUND: Cardiac surgery patients represent a high-risk cohort in intensive care units (ICUs). Central venous pressure (CVP) measurement seems to remain an integral part in hemodynamic monitoring, especially in cardio-surgical ICUs. However, its value as a prognostic marker for organ failure is still unclear. Therefore, we analyzed postoperative CVP values after adult cardiac surgery in a large cohort with regard to its prognostic value for morbidity and mortality. METHODS: All adult patients admitted to our ICUs between 2006 and 2019 after cardiac surgery were eligible for inclusion in the study (n = 11,198). We calculated the median initial CVP (miCVP) after admission to the ICU, which returned valid values for 9802 patients. An ROC curve analysis for optimal cut-off miCVP to predict ICU mortality was conducted with consecutive patient allocation into a (a) low miCVP (LCVP) group (≤11 mmHg) and (b) high miCVP (HCVP) group (>11 mmHg). We analyzed the impact of high miCVP on morbidity and mortality by propensity score matching (PSM) and logistic regression. RESULTS: ICU mortality was increased in HCVP patients. In addition, patients in the HCVP group required longer mechanical ventilation, had a higher incidence of acute kidney injury, were more frequently treated with renal replacement therapy, and showed a higher risk for postoperative liver dysfunction, parametrized by a postoperative rise of ≥ 10 in MELD Score. Multiple regression analysis confirmed HCVP has an effect on postoperative ICU-mortality and intrahospital mortality, which seems to be independent. CONCLUSIONS: A high initial CVP in the early postoperative ICU course after cardiac surgery is associated with worse patient outcome. Whether or not CVP, as a readily and constantly available hemodynamic parameter, should promote clinical efforts regarding diagnostics and/or treatment, warrants further investigations.

STRIPAK Members Orchestrate Hippo and Insulin Receptor Signaling to Promote Neural Stem Cell Reactivation.

Adult stem cells reactivate from quiescence to maintain tissue homeostasis and in response to injury. How the underlying regulatory signals are integrated is largely unknown. Drosophila neural stem cells (NSCs) also leave quiescence to generate adult neurons and glia, a process that is dependent on Hippo signaling inhibition and activation of the insulin-like receptor (InR)/PI3K/Akt cascade. We performed a transcriptome analysis of individual quiescent and reactivating NSCs harvested directly from Drosophila brains and identified the conserved STRIPAK complex members mob4, cka, and PP2A (microtubule star, mts). We show that PP2A/Mts phosphatase, with its regulatory subunit Widerborst, maintains NSC quiescence, preventing premature activation of InR/PI3K/Akt signaling. Conversely, an increase in Mob4 and Cka levels promotes NSC reactivation. Mob4 and Cka are essential to recruit PP2A/Mts into a complex with Hippo kinase, resulting in Hippo pathway inhibition. We propose that Mob4/Cka/Mts functions as an intrinsic molecular switch coordinating Hippo and InR/PI3K/Akt pathways and enabling NSC reactivation.

What is popular? Distinguishing bullying and aggression as status correlates within specific peer normative contexts

Abstract This study tested social status correlates of aggression and bullying and how these are influenced by peer groups' normative beliefs about aggression and prosocial behavior among 1165 fourth, fifth and sixth graders in Chile. Associations between aggression and popularity (positive) and social preference (negative) were confirmed, whereas bullying was negatively associated with both dimensions. Normative beliefs about aggression and prosocial behavior were assessed at the group level, while social status was assessed at the classroom level through peer nominations. Hierarchical Linear Analyses showed that in groups with a higher value associated with aggression, classmates rated aggressive peers as less popular but also less disliked. The status correlates of bullying remained unaffected by peer normative beliefs. The discussion focuses on the social function of aggression as compared to the social sanction associated with bullying, and on the specificity of these associations at different layers of the social ecology. (AU)

Programa para el Bienestar y Aprendizaje Socioemocional en estudiantes de tercero y cuarto grado: descripción y evaluación de impa / Learning and wellbeing program for third and fourth grade students: Impact description and evaluation

El presente trabajo describe un programa para favorecer el bienestar y aprendizaje socioemocional en estudiantes de tercer y cuarto año de Enseñanza General Básica, y su evaluación de impacto. Los fundamentos conceptuales del programa para el Bienestar y Aprendizaje Socioemocional se apoyan en la perspectiva del aprendizaje socioemocional, que integra factores tanto en el ámbito individual como del contexto. El programa enfatiza el desarrollo de vínculos interpersonales de calidad y el desarrollo de las competencias necesarias para ello. A través de un diseño cuasiexperimental que incluyó a 647 estudiantes de tercero y cuarto grado en cinco colegios particulares subvencionados de Santiago, Chile, la evaluación con análisis de la varianza de medidas repetidas mostró un impacto del programa en la autoestima de los estudiantes percibida por sus profesores (medida a través del test de autoestima). Asimismo, el programa mitigó el descenso en la percepción del clima escolar según la Escala de Clima Social, en indicadores de integración social, y en el rendimiento escolar, que se observó en el grupo control. Se discuten los resultados del programa y sus posibles implicancias para el desarrollo de intervenciones en este campo.

This paper presents a program to foster socioemotional learning and wellbeing in 3rd and 4th graders, and its impact on evaluation. The program is conceptually grounded in the socioemotional learning perspective, which integrates factors both at the individual and contextual levels. Development of quality interpersonal bonding is emphasized, as is the development of the necessary socioemotional skills to achieve this goal. A quasi experimental design was implemented which included tudents in five private subsidized schools in Santiago, Chile. Evaluation with Anova analysis of repeated measures showed an impact of the program on students' self-esteem reported by the teacher (measured with TAE). Seemingly, the program mitigated the decrease in the perception of school social climate (measured with ECLIS), in social integration, and in academic performance, as observed in the control group. Results are discussed in terms of their implications for the development of interventions in this field.

Rendimiento académico y las dimensiones personal y contextual del aprendizaje socioemocional: evidencias de su asociación en estudiantes chilenos / Academic Performance and Personal and Contextual Dimensions of Socioemotional Learning: Evidence of its Association in Chilean Students

El presente estudio respalda la creciente evidencia empírica sobre la relación entre la dimensión socioemocional y el rendimiento académico. Mediante análisis de correlación y regresión se testeó en estudiantes chilenos de educación básica la asociación entre el rendimiento académico y las dimensiones individual (autoestima y bienestar socioemocional) y contextual (percepción del clima social escolar) del aprendizaje socioemocional. Bienestar socioemocional y percepción del clima social escolar respecto a relaciones de pares y lugares de la escuela, mostraron una relación significativa con el aumento en el desempeño académico. Los hallazgos son discutidos en términos de sus implicancias para la práctica educativa y para futuras investigaciones.

This study supports the growing empirical evidence regarding the relationship between the socioemotional dimension and academic achievement. Through correlation and regression analyses the associations between individual (self-steem and socioemotional well-being) and contextual (perception of the school social climate) features of socioemotional learning and academic success in Chilean elementary students were tested. Socioemotional well-being and perception of school social climate with regards to peer relations and places at school were significantly related to improvements in academic achievement. Results are discussed in terms of their implications for educational practice and future research.

Long-term live cell imaging and automated 4D analysis of drosophila neuroblast lineages.

The developing Drosophila brain is a well-studied model system for neurogenesis and stem cell biology. In the Drosophila central brain, around 200 neural stem cells called neuroblasts undergo repeated rounds of asymmetric cell division. These divisions typically generate a larger self-renewing neuroblast and a smaller ganglion mother cell that undergoes one terminal division to create two differentiating neurons. Although single mitotic divisions of neuroblasts can easily be imaged in real time, the lack of long term imaging procedures has limited the use of neuroblast live imaging for lineage analysis. Here we describe a method that allows live imaging of cultured Drosophila neuroblasts over multiple cell cycles for up to 24 hours. We describe a 4D image analysis protocol that can be used to extract cell cycle times and growth rates from the resulting movies in an automated manner. We use it to perform lineage analysis in type II neuroblasts where clonal analysis has indicated the presence of a transit-amplifying population that potentiates the number of neurons. Indeed, our experiments verify type II lineages and provide quantitative parameters for all cell types in those lineages. As defects in type II neuroblast lineages can result in brain tumor formation, our lineage analysis method will allow more detailed and quantitative analysis of tumorigenesis and asymmetric cell division in the Drosophila brain.

Preubiquitinated chimeric ErbB2 is constitutively endocytosed and subsequently degraded in lysosomes.

The oncoprotein ErbB2 is endocytosis-deficient, probably due to its interaction with Heat shock protein 90. We previously demonstrated that clathrin-dependent endocytosis of ErbB2 is induced upon incubation of cells with Ansamycin derivatives, such as geldanamycin and its derivative 17-AAG. Furthermore, we have previously demonstrated that a preubiquitinated chimeric EGFR (EGFR-Ub(4)) is constitutively endocytosed in a clathrin-dependent manner. We now demonstrate that also an ErbB2-Ub(4) chimera is endocytosed constitutively and clathrin-dependently. Upon expression, the ErbB2-Ub(4) was further ubiquitinated, and by Western blotting, we demonstrated the formation of both Lys48-linked and Lys63-linked polyubiquitin chains. ErbB2-Ub(4) was constitutively internalized and eventually sorted to late endosomes and lysosomes where the fusion protein was degraded. ErbB2-Ub(4) was not cleaved prior to internalization. Interestingly, over-expression of Ubiquitin Interaction Motif-containing dominant negative fragments of the clathrin adaptor proteins epsin1 and Eps15 negatively affected endocytosis of ErbB2. Altogether, this argues that ubiquitination is sufficient to induce clathrin-mediated endocytosis and lysosomal degradation of the otherwise plasma membrane localized ErbB2. Also, it appears that C-terminal cleavage is not required for endocytosis.

Cardiopulmonary bypass during cardiac surgery modulates systemic inflammation by affecting different steps of the leukocyte recruitment cascade.

BACKGROUND: It is known that the use of a cardiopulmonary bypass (CPB) during cardiac surgery leads to leukocyte activation and may, among other causes, induce organ dysfunction due to increased leukocyte recruitment into different organs. Leukocyte extravasation occurs in a cascade-like fashion, including capturing, rolling, adhesion, and transmigration. However, the molecular mechanisms of increased leukocyte recruitment caused by CPB are not known. This clinical study was undertaken in order to investigate which steps of the leukocyte recruitment cascade are affected by the systemic inflammation during CPB. METHODS: We investigated the effects of CPB on the different steps of the leukocyte recruitment cascade in whole blood from healthy volunteers (n = 9) and patients undergoing cardiac surgery with the use of cardiopulmonary bypass (n = 7) or in off-pump coronary artery bypass-technique (OPCAB, n = 9) by using flow chamber experiments, transmigration assays, and biochemical analysis. RESULTS: CPB abrogated selectin-induced slow leukocyte rolling on E-selectin/ICAM-1 and P-selectin/ICAM-1. In contrast, chemokine-induced arrest and transmigration was significantly increased by CPB. Mechanistically, the abolishment of slow leukocyte rolling was due to disturbances in intracellular signaling with reduced phosphorylation of phospholipase C (PLC) γ2, Akt, and p38 MAP kinase. Furthermore, CPB induced an elevated transmigration which was caused by upregulation of Mac-1 on neutrophils. CONCLUSION: These data suggest that CPB abrogates selectin-mediated slow leukocyte rolling by disturbing intracellular signaling, but that the clinically observed increased leukocyte recruitment caused by CPB is due to increased chemokine-induced arrest and transmigration. A better understanding of the underlying molecular mechanisms causing systemic inflammation after CPB may aid in the development of new therapeutic approaches.

Cetuximab in combination with anti-human IgG antibodies efficiently down-regulates the EGF receptor by macropinocytosis.

The monoclonal antibody C225 (Cetuximab) blocks binding of ligand to the epidermal growth factor receptor (EGFR). In addition, it is known that incubation with C225 induces endocytosis of the EGFR. This endocytosis has previously been shown to be increased when C225 is combined with an additional monoclonal anti-EGFR antibody. However, the effects of antibody combinations on EGFR activation, endocytosis, trafficking and degradation have been unclear. By binding a secondary antibody to the C225-EGFR complex, we here demonstrate that a combination of antibodies can efficiently internalize and degrade the EGFR. Although the combination of antibodies activated the EGFR kinase and induced ubiquitination of the EGFR, the kinase activity was not required for internalization of the EGFR. In contrast to EGF-induced EGFR down-regulation, the antibody combination efficiently degraded the EGFR without initiating downstream proliferative signaling. The antibody-induced internalization of EGFR was found not to depend on clathrin and/or dynamin, but depended on actin polymerization, suggesting induction of macropinocytosis. Macropinocytosis may cause internalization of large membrane areas, and this could explain the highly efficient internalization of the EGFR induced by combination of antibodies.

FACS purification and transcriptome analysis of drosophila neural stem cells reveals a role for Klumpfuss in self-renewal.

Drosophila neuroblasts (NBs) have emerged as a model for stem cell biology that is ideal for genetic analysis but is limited by the lack of cell-type-specific gene expression data. Here, we describe a method for isolating large numbers of pure NBs and differentiating neurons that retain both cell-cycle and lineage characteristics. We determine transcriptional profiles by mRNA sequencing and identify 28 predicted NB-specific transcription factors that can be arranged in a network containing hubs for Notch signaling, growth control, and chromatin regulation. Overexpression and RNA interference for these factors identify Klumpfuss as a regulator of self-renewal. We show that loss of Klumpfuss function causes premature differentiation and that overexpression results in the formation of transplantable brain tumors. Our data represent a valuable resource for investigating Drosophila developmental neurobiology, and the described method can be applied to other invertebrate stem cell lineages as well.

Nimotuzumab and cetuximab block ligand-independent EGF receptor signaling efficiently at different concentrations.

The epidermal growth factor receptor (EGFR) is overexpressed in several epithelial tumors such as breast, ovarian, and colon cancers. Nimotuzumab and Cetuximab are antibodies that inhibit ligand binding upon interaction with the EGFR, thereby indirectly inactivating the EGFR kinase. The ability of an antibody to counteract growth depends on its mechanism of action as well as on its binding affinity. Nimotuzumab has lower binding affinity for the EGFR than does Cetuximab. In addition, a mechanistic difference has recently been suggested to explain the different clinical effects of Nimotuzumab and Cetuximab, arguing that Nimotuzumab partly permits kinase activity and downstream signaling under conditions where binding of EGF is inhibited. We have in the current study compared the effects of Nimotuzumab and Cetuximab on binding of EGF as well as on inhibition of constitutive EGFR-ErbB2 dimerization and downstream activation of Erk. Our results demonstrate that (at least in EGFR-overexpressing cells), in contrast to the recently published mechanistic model, Nimotuzumab not only inhibits EGF-stimulated, but also ligand-independent (basal) signaling although at higher concentrations than required with Cetuximab.