Ligand-specific c-Fos expression emerges from the spatiotemporal control of ErbB network dynamics.

Activation of ErbB receptors by epidermal growth factor (EGF) or heregulin (HRG) determines distinct cell-fate decisions, although signals propagate through shared pathways. Using mathematical modeling and experimental approaches, we unravel how HRG and EGF generate distinct, all-or-none responses of the phosphorylated transcription factor c-Fos. In the cytosol, EGF induces transient and HRG induces sustained ERK activation. In the nucleus, however, ERK activity and c-fos mRNA expression are transient for both ligands. Knockdown of dual-specificity phosphatases extends HRG-stimulated nuclear ERK activation, but not c-fos mRNA expression, implying the existence of a HRG-induced repressor of c-fos transcription. Further experiments confirmed that this repressor is mainly induced by HRG, but not EGF, and requires new protein synthesis. We show how a spatially distributed, signaling-transcription cascade robustly discriminates between transient and sustained ERK activities at the c-Fos system level. The proposed control mechanisms are general and operate in different cell types, stimulated by various ligands.

A Prospective Multicenter Comparison of Trauma and Injury Severity Score, American Society of Anesthesiologists Physical Status, and National Surgical Quality Improvement Program Calculator's Ability to Predict Operative Trauma Outcomes.

BACKGROUND: Trauma outcome prediction models have traditionally relied upon patient injury and physiologic data (eg, Trauma and Injury Severity Score [TRISS]) without accounting for comorbidities. We sought to prospectively evaluate the role of the American Society of Anesthesiologists physical status (ASA-PS) score and the National Surgical Quality Improvement Program Surgical Risk-Calculator (NSQIP-SRC), which are measurements of comorbidities, in the prediction of trauma outcomes, hypothesizing that they will improve the predictive ability for mortality, hospital length of stay (LOS), and complications compared to TRISS alone in trauma patients undergoing surgery within 24 hours. METHODS: A prospective, observational multicenter study (9/2018-2/2020) of trauma patients ≥18 years undergoing operation within 24 hours of admission was performed. Multiple logistic regression was used to create models predicting mortality utilizing the variables within TRISS, ASA-PS, and NSQIP-SRC, respectively. Linear regression was used to create models predicting LOS and negative binomial regression to create models predicting complications. RESULTS: From 4 level I trauma centers, 1213 patients were included. The Brier Score for each model predicting mortality was found to improve accuracy in the following order: 0.0370 for ASA-PS, 0.0355 for NSQIP-SRC, 0.0301 for TRISS, 0.0291 for TRISS+ASA-PS, and 0.0234 for TRISS+NSQIP-SRC. However, when comparing TRISS alone to TRISS+ASA-PS (P = .082) and TRISS+NSQIP-SRC (P = .394), there was no significant improvement in mortality prediction. NSQIP-SRC more accurately predicted both LOS and complications compared to TRISS and ASA-PS. CONCLUSIONS: TRISS predicts mortality better than ASA-PS and NSQIP-SRC in trauma patients undergoing surgery within 24 hours. The TRISS mortality predictive ability is not improved when combined with ASA-PS or NSQIP-SRC. However, NSQIP-SRC was the most accurate predictor of LOS and complications.

A Positive Cocaine Urine Toxicology Test and the Effect on Intraoperative Hemodynamics Under General Anesthesia.

BACKGROUND: Cocaine has a short biological half-life, but inactive urine metabolites may be detectable for a week following use. It is unclear if patients who test positive for cocaine but have a normal electrocardiogram and vital signs have a greater percentage of hemodynamic events intraoperatively. METHODS: A total of 328 patients with a history of cocaine use who were scheduled for elective noncardiac surgery under general anesthesia were enrolled. Patients were categorized into cocaine-positive versus cocaine-negative groups based on the results of their urine cocaine toxicology test. The primary aim of this study was to evaluate whether asymptomatic cocaine-positive patients had similar percentages of intraoperative hemodynamic events, defined as (1) a mean arterial blood pressure (MAP) of <65 or >105 mm Hg and (2) a heart rate (HR) of <50 or >100 beats per minute (bpm) compared to cocaine-negative patients. The study was powered to assess if the 2 groups had an equivalent mean percent of intraoperative hemodynamic events within specific limits using an equivalence test of means consisting of 2 one-sided tests. RESULTS: The cocaine-positive group had a blood pressure (BP) that was outside the set limits 19.4% (standard deviation [SD] 17.7%) of the time versus 23.1% (SD 17.7%) in the cocaine-negative group (95% confidence interval [CI], 0.5-7.0). The cocaine-positive group had a HR outside the set limits 9.6% (SD 16.2%) of the time versus 8.2% (SD 14.9%) in the cocaine-negative group (95% CI, 4.3-1.5). Adjusted for age, sex, body mass index (BMI), smoking status, and the presence of comorbid hypertension, renal disease, and psychiatric illness, the cocaine-positive and cocaine-negative patients were similar within a 7.5% margin of equivalence for MAP data (ß coefficient = 2%, P = .003, CI, 2-6) and within a 5% margin of equivalence for HR data (ß coefficient = 0.2%, P < .001, CI, 4-3). CONCLUSIONS: Asymptomatic cocaine-positive patients undergoing elective noncardiac surgery under general anesthesia have similar percentages of intraoperative hemodynamic events compared to cocaine-negative patients.

Media supplementation for targeted manipulation of monoclonal antibody galactosylation and fucosylation.

Monoclonal antibodies are critically important biologics as the largest class of molecules used to treat cancers, rheumatoid arthritis, and other chronic diseases. Antibody glycosylation is a critical quality attribute that has ramifications for patient safety and physiological efficacy-one that can be modified by such factors as media formulation and process conditions during production. Using a design-of-experiments approach, we examined the effect of 2-F-peracetyl fucose (2FP), uridine, and galactose on cell growth and metabolism, titer, and gene expression of key glycosylation-related proteins, and report how the glycoform distribution changed from Days 4 to 7 in a batch process used for IgG1 production from Chinese hamster ovary cells. We observed major glycosylation changes upon supplement addition, where the addition of 2FP decreased antibody fucosylation by up to 48%, galactose addition increased galactosylation by up to 21%, and uridine addition decreased fucosylation and increased galactosylation by 6% and 2%, respectively. Despite having major effects on glycosylation, neither galactose nor 2FP significantly affected cell culture growth, metabolism, or titer. Uridine improved peak cell densities by 23% but also reduced titer by ∼30%. The supplements caused significant changes in gene expression by Day 4 of the cultures where 2FP addition significantly reduced fucosyltransferase 8 and nucleotide sugar transporter gene expression (by ∼2-fold), and uridine addition significantly increased expression of UDP-GlcNAcT (SLC35A3) and B4GALT1-6 genes (by 1.5-3-fold). These gene expression data alongside glycosylation, metabolic, and growth data improve our understanding of the cellular mechanisms affected by media supplementation and suggest approaches for modifying antibody glycosylation in antibody production processes.

The influence of morbid obesity on difficult intubation and difficult mask ventilation.

PURPOSE: To determine the influence of morbid obesity on the incidence of difficult mask ventilation and difficult intubation. METHODS: Over a 6-year period, all tracheal intubations in the operating room of a large tertiary teaching hospital were analyzed. A modified version of the intubation difficulty scale (mIDS) was used to define easy versus difficult intubation, where a score of two or greater was defined as difficult intubation. Difficult mask ventilation was defined as the use of one or more adjuncts to achieve successful mask ventilation. RESULTS: Of 45,447 analyzed cases, 1893 (4.2%) were classified as difficult intubations. Morbidly obese patients were not more likely to have difficult intubation [Odds Ratio (OR) = 1.131, 95% confidence interval (CI): 0.958, 1.334, p = 0.146]. Factors that were associated with difficult intubation included patient age > 46 years, male sex, Mallampati 3-4, thyromental distance < 6 cm, and the presence of intact dentition. Of 37,016 cases in which mask ventilation was attempted, 1069 (2.9%) were difficult. Morbidly obese patients were more likely to have difficult mask ventilation (OR = 3.785, 95% CI: 3.188, 4.493, p < 0.0001). Other factors associated with difficult mask ventilation included patient age > 46 years, male sex, Mallampati 3-4, and a history of obstructive sleep apnea. Having intact dentition decreased the likelihood of difficult mask ventilation. CONCLUSION: Morbidly obese patients do not have a higher incidence of difficult intubation compared to non-morbidly obese patients. However, they have a significantly higher incidence of difficult mask ventilation. Other factors that are predictive of both difficult mask ventilation and difficult intubation include age > 46 years, male sex, and Mallampati 3-4.

Inputs drive cell phenotype variability.

What is the significance of the extensive variability observed in individual members of a single-cell phenotype? This question is particularly relevant to the highly differentiated organization of the brain. In this study, for the first time, we analyze the in vivo variability within a neuronal phenotype in terms of input type. We developed a large-scale gene-expression data set from several hundred single brainstem neurons selected on the basis of their specific synaptic input types. The results show a surprising organizational structure in which neuronal variability aligned with input type along a continuum of sub-phenotypes and corresponding gene regulatory modules. Correlations between these regulatory modules and specific cellular states were stratified by synaptic input type. Moreover, we found that the phenotype gradient and correlated regulatory modules were maintained across subjects. As these specific cellular states are a function of the inputs received, the stability of these states represents "attractor"-like states along a dynamic landscape that is influenced and shaped by inputs, enabling distinct state-dependent functional responses. We interpret the phenotype gradient as arising from analog tuning of underlying regulatory networks driven by distinct inputs to individual cells. Our results change the way we understand how a phenotypic population supports robust biological function by integrating the environmental experience of individual cells. Our results provide an explanation of the functional significance of the pervasive variability observed within a cell type and are broadly applicable to understanding the relationship between cellular input history and cell phenotype within all tissues.

Adiponectin fine-tuning of liver regeneration dynamics revealed through cellular network modelling.

Following partial hepatectomy, the liver initiates a regenerative programme involving hepatocyte priming and replication driven by the coordinated actions of cytokine and growth factors. We investigated the mechanisms underlying adiponectin's (Adn) regulation of liver regeneration through modulation of these mediators. Adn(-/-) mice showed delayed onset of hepatocyte replication, but accelerated cell cycle progression relative to wild-type mice, suggesting Adn has multiple effects fine-tuning the kinetics of liver regeneration. We developed a computational model describing the molecular and physiological kinetics of liver regeneration in Adn(-/-) mice. We employed this computational model to evaluate the underlying regulatory mechanisms. Our analysis predicted that Adn is required for an efficient early cytokine response to partial hepatectomy, but is inhibitory to later growth factor actions. Consistent with this prediction, Adn knockout reduced hepatocyte responses to interleukin-6 during the priming phase, but enhanced growth factor levels through peak hepatocyte replication. By contrast, supraphysiological concentrations of Adn resulting from rosiglitazone treatment suppressed regeneration by reducing growth factor levels during S phase, consistent with computational predictions. Together, these results revealed that Adn fine-tunes the progression of liver regeneration through dynamically modulating molecular mediator networks and cellular interactions within the liver.

Transversus Abdominis Plane Block Versus Surgical Site Infiltration for Pain Management After Open Total Abdominal Hysterectomy.

BACKGROUND: Surgical site infiltration and transversus abdominis plane (TAP) blocks are commonly used to improve pain relief after lower abdominal surgery. This randomized, observer-blinded study was designed to compare the analgesic efficacy of TAP blocks with surgical site infiltration in patients undergoing open total abdominal hysterectomy via a Pfannenstiel incision. METHODS: Patients were randomized to receive either bilateral ultrasound-guided TAP blocks using bupivacaine 0.5% 20 mL on each side (n = 30) or surgical site infiltration with liposomal bupivacaine 266 mg diluted to 60 mL injected in the preperitoneal, subfascial, and subcutaneous planes (n = 30). The remaining aspects of the perioperative care were standardized. An investigator blinded to the group allocation documented pain scores at rest and with coughing, opioid requirements, nausea, vomiting, and rescue antiemetics in the postanesthesia care unit and at 2, 6, 12, 24, and 48 hours postoperatively. The primary outcome measure was pain scores on coughing at 6 hours postoperatively. RESULTS: One patient in each group was excluded from the analysis because of reoperation within 24 hours in the TAP block group and change of incision type in the infiltration group. The pain scores at rest and with coughing were significantly lower in the surgical site infiltration group at all postoperative time points (P < 0.0001) except at rest in the postanesthesia care unit. The opioid requirements between 24 and 48 hours were significantly lower in the infiltration group (P = 0.009). The nausea scores, occurrence of vomiting, and need for rescue antiemetics were similar. CONCLUSIONS: Surgical site infiltration provided superior pain relief at rest and on coughing, as well as reduced opioid consumption for up to 48 hours. Future studies need to compare TAP blocks with liposomal bupivacaine with surgical site infiltration with liposomal bupivacaine.

Identification of manipulated variables for a glycosylation control strategy.

N-linked glycan distribution affects important end-use characteristics such as the bioactivity and efficacy of many therapeutic proteins, (including monoclonal antibodies), in vivo. Yet, obtaining desired glycan distributions consistently during batch-to-batch production can be challenging for biopharmaceutical manufacturers. While an appropriately implemented on-line glycosylation control strategy during production can help to ensure a consistent glycan distribution, to date no such strategies have been reported. Our goal is to develop and validate a comprehensive strategy for effective on-line control of glycosylation, the successful achievement of which requires first identifying appropriate manipulated variables that can be used to direct the glycan distribution to a desired state. While various culture conditions such as bioreactor process variables, media type, and media supplements have been shown to affect the glycan distribution, in this study we focus on the latter. Specifically, we implemented a statistically designed series of experiments to determine the significant main effects (as well as interaction effects) of media supplementation with manganese, galactose, ammonia and found that each had significant effects on certain glycans. We also include data indicating the glycosylation enzyme gene transcript levels as well as the intracellular nucleotide sugar concentrations in the presence of the media supplements to provide insight into the intracellular conditions that may be contributing to the changes in glycan distribution. The acquired experimental data sets were then used to identify which glycans can be controlled by the media supplements and to what degree. We determined that MnCl2 can be used as a manipulated variable to increase the relative abundance of M51 and decrease FA2 simultaneously, and galactose can be used as a manipulated variable to increase the relative abundance of FA2G1 and decrease FA2 and A2 simultaneously.

Coordinated dynamic gene expression changes in the central nucleus of the amygdala during alcohol withdrawal.

BACKGROUND: Chronic alcohol use causes widespread changes in the cellular biology of the amygdala's central nucleus (CeA), a GABAergic center that integrates autonomic physiology with the emotional aspects of motivation and learning. While alcohol-induced neurochemical changes play a role in dependence and drinking behavior, little is known about the CeA's dynamic changes during withdrawal, a period of emotional and physiologic disturbance. METHODS: We used a qRT-PCR platform to measure 139 transcripts in 92 rat CeA samples from control (N = 33), chronically alcohol exposed (N = 26), and withdrawn rats (t = 4, 8, 18, 32, and 48 hours; N = 5, 10, 7, 6, 5). This focused transcript set allowed us to identify significant dynamic expression patterns during the first 48 hours of withdrawal and propose potential regulatory mechanisms. RESULTS: Chronic alcohol exposure causes a limited number of small magnitude expression changes. In contrast, withdrawal results in a greater number of large changes within 4 hours of removal of the alcohol diet. Sixty-five of the 139 measured transcripts (47%) showed differential regulation during withdrawal. Over the 48-hour period, dynamic changes in the expression of γ-aminobutyric acid type A (GABA(A) ), ionotropic glutamate and neuropeptide system-related G-protein-coupled receptor subunits, and the Ras/Raf signaling pathway were seen as well as downstream transcription factors (TFs) and epigenetic regulators. Four temporally correlated gene clusters were identified with shared functional roles including NMDA receptors, MAPKKK and chemokine signaling cascades, and mediators of long-term potentiation, among others. Cluster promoter regions shared overrepresented binding sites for multiple TFs including Cebp, Usf-1, Smad3, Ap-2, and c-Ets, suggesting a potential regulatory role. CONCLUSIONS: During alcohol withdrawal, the CeA experiences rapid changes in mRNA expression of these functionally related transcripts that were not predicted by measurement during chronic exposure. This study provides new insight into dynamic expression changes during alcohol withdrawal and suggests novel regulatory relationships that potentially impact the aspects of emotional modulation.

Elucidating the Mechanisms of Dynamic and Robust Control of the Liver Homeostatic Renewal Process: Cell Network Modeling and Analysis.

Recent experimental investigations of liver homeostatic renewal have identified high replication capacity hepatocyte populations as the primary maintainers of liver mass. However, the molecular and cellular processes controlling liver homeostatic renewal remain unknown. To address this problem, we developed and analyzed a mathematical model describing cellular network interactions underlying liver homeostatic renewal. Model simulation results demonstrate that without feedback control, basic homeostatic renewal is not robust to disruptions, leading to tissue loss under persistent/repetitive insults. Consequently, we extended our basic model to incorporate putative regulatory interactions and investigated how such interactions may confer robustness on the homeostatic renewal process. We utilized a Design of Experiments approach to identify the combination of feedback interactions that yields a cell network model of homeostatic renewal capable of maintaining liver mass robustly during persistent/repetitive injury. Simulations of this robust model indicate that repeated injury destabilizes liver homeostasis within several months, which differs from epidemiological observations of a much slower decay of liver function occurring over several years. To address this discrepancy, we extended the model to include feedback control by liver nonparenchymal cells. Simulations and analysis of the final multicellular feedback control network suggest that achieving robust liver homeostatic renewal requires intrinsic stability in a hepatocellular network combined with feedback control by nonparenchymal cells.

Closed-loop modeling of central and intrinsic cardiac nervous system circuits underlying cardiovascular control.

The baroreflex is a multi-input, multi-output control physiological system that regulates blood pressure by modulating nerve activity between the brainstem and the heart. Existing computational models of the baroreflex do not explictly incorporate the intrinsic cardiac nervous system (ICN), which mediates central control of the heart function. We developed a computational model of closed-loop cardiovascular control by integrating a network representation of the ICN within central control reflex circuits. We examined central and local contributions to the control of heart rate, ventricular functions, and respiratory sinus arrhythmia (RSA). Our simulations match the experimentally observed relationship between RSA and lung tidal volume. Our simulations predicted the relative contributions of the sensory and the motor neuron pathways to the experimentally observed changes in the heart rate. Our closed-loop cardiovascular control model is primed for evaluating bioelectronic interventions to treat heart failure and renormalize cardiovascular physiology.

Systems Engineering Approach to Modeling and Analysis of Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by airflow limitation. This study develops a systems engineering framework for representing important mechanistic details of COPD in a model of the cardiorespiratory system. In this model, we present the cardiorespiratory system as an integrated biological control system responsible for regulating breathing. Four engineering control system components are considered: sensor, controller, actuator, and the process itself. Knowledge of human anatomy and physiology is used to develop appropriate mechanistic mathematical models for each component. Following a systematic analysis of the computational model, we identify three physiological parameters associated with reproducing clinical manifestations of COPD: changes in the forced expiratory volume, lung volumes, and pulmonary hypertension. We quantify the changes in these parameters (airway resistance, lung elastance, and pulmonary resistance) as the ones that result in a systemic response that is diagnostic of COPD. A multivariate analysis of the simulation results reveals that the changes in airway resistance have a broad impact on the human cardiorespiratory system and that the pulmonary circuit is stressed beyond normal under hypoxic environments in most COPD patients.

Comparison of National Surgical Quality Improvement Program Surgical Risk Calculator and Trauma and Injury Severity Score Risk Assessment Tools in Predicting Outcomes in High-Risk Operative Trauma Patients.

BACKGROUND: The Trauma and Injury Severity Score (TRISS) uses anatomic/physiologic variables to predict outcomes. The National Surgical Quality Improvement Program Surgical Risk Calculator (NSQIP-SRC) includes functional status and comorbidities. It is unclear which of these tools is superior for high-risk trauma patients (American Society of Anesthesiologists Physical Status (ASA-PS) class IV or V). This study compares risk prediction of TRISS and NSQIP-SRC for mortality, length of stay (LOS), and complications for high-risk operative trauma patients. METHODS: This is a prospective study of high-risk (ASA-PS IV or V) trauma patients (≥18 years-old) undergoing surgery at 4 trauma centers. We compared TRISS vs NSQIP-SRC vs NSQIP-SRC + TRISS for ability to predict mortality, LOS, and complications using linear, logistic, and negative binomial regression. RESULTS: Of 284 patients, 48 (16.9%) died. The median LOS was 16 days and number of complications was 1. TRISS + NSQIP-SRC best predicted mortality (AUROC: .877 vs .723 vs .843, P = .0018) and number of complications (pseudo-R2/median error (ME) 5.26%/1.15 vs 3.39%/1.33 vs 2.07%/1.41, P < .001) compared to NSQIP-SRC or TRISS, but there was no difference between TRISS + NSQIP-SRC and NSQIP-SRC with LOS prediction (P = .43). DISCUSSION: For high-risk operative trauma patients, TRISS + NSQIP-SRC performed better at predicting mortality and number of complications compared to NSQIP-SRC or TRISS alone but similar to NSQIP-SRC alone for LOS. Thus, future risk prediction and comparisons across trauma centers for high-risk operative trauma patients should include a combination of anatomic/physiologic data, comorbidities, and functional status.

A spatial model for integrin clustering as a result of feedback between integrin activation and integrin binding.

Integrins are transmembrane adhesion receptors that bind extracellular matrix (ECM) proteins and signal bidirectionally to regulate cell adhesion and migration. In many cell types, integrins cluster at cell-ECM contacts to create the foundation for adhesion complexes that transfer force between the cell and the ECM. Even though the temporal and spatial regulation of these integrin clusters is essential for cell migration, how cells regulate their formation is currently unknown. It has been shown that integrin cluster formation is independent of actin stress fiber formation, but requires active (high-affinity) integrins, phosphoinositol-4,5-bisphosphate (PIP2), talin, and immobile ECM ligand. Based on these observations, we propose a minimal model for initial formation of integrin clusters, facilitated by localized activation and binding of integrins to ECM ligands as a result of biochemical feedback between integrin binding and integrin activation. By employing a diffusion-reaction framework for modeling these reactions, we show how spatial organization of bound integrins into clusters may be achieved by a local source of active integrins, namely protein complexes formed on the cytoplasmic tails of bound integrins. Further, we show how such a mechanism can turn small local increases in the concentration of active talin or active integrin into integrin clusters via positive feedback. Our results suggest that the formation of integrin clusters by the proposed mechanism depends on the relationships between production and diffusion of integrin-activating species, and that changes to the relative rates of these processes may affect the resulting properties of integrin clusters.

Rapid temporal changes in the expression of a set of neuromodulatory genes during alcohol withdrawal in the dorsal vagal complex: molecular evidence of homeostatic disturbance.

BACKGROUND: Chronic alcohol exposure produces neuroadaptation, which increases the risk of cellular excitotoxicity and autonomic dysfunction during withdrawal. The temporal progression and regulation of the gene expression that contributes to this physiologic and behavioral phenotype is poorly understood early in the withdrawal period. Further, it is unexplored in the dorsal vagal complex (DVC), a brainstem autonomic regulatory structure. METHODS: We use a quantitative polymerase chain reaction platform to precisely and simultaneously measure the expression of 145 neuromodulatory genes in more than 100 rat DVC samples from control, chronically alcohol-exposed, and withdrawn rats. To gain insight into the dynamic progression and regulation of withdrawal, we focus on the expression of a subset of functionally relevant genes during the first 48 hours, when behavioral symptoms are most severe. RESULTS: In the DVC, expression of this gene subset is essentially normal in chronically alcohol-exposed rats. However, withdrawal results in rapid, large-magnitude expression changes in this group. We observed differential regulation in 86 of the 145 genes measured (59%), some as early as 4 hours into withdrawal. Time series measurements (4, 8, 18, 32, and 48 hours after alcohol removal) revealed dynamic expression responses in immediate early genes, γ-aminobutyric acid type A, ionotropic glutamate, and G-protein coupled receptors and the Ras/Raf signaling pathway. Together, these changes elucidate a complex, temporally coordinated response that involves correlated expression of many functionally related groups. In particular, the expression patterns of Gabra1, Grin2a, Grin3a, and Grik3 were tightly correlated. These receptor subunits share overrepresented transcription factor binding sites for Pax-8 and other transcription factors, suggesting a common regulatory mechanism and a role for these transcription factors in the regulation of neurotransmission within the first 48 hours of alcohol withdrawal. CONCLUSIONS: Expression in this gene set is essentially normal in the alcohol-adapted DVC, but withdrawal results in immediate, large-magnitude, and dynamic changes. These data support both increased research focus on the biological ramifications of alcohol withdrawal and enable novel insights into the dynamic withdrawal expression response in this understudied homeostatic control center.

Rational Design of Hydrogel Networks with Dynamic Mechanical Properties to Mimic Matrix Remodeling.

Engineered hydrogels are increasingly used as extracellular matrix (ECM) surrogates for probing cell function in response to ECM remodeling events related to injury or disease (e.g., degradation followed by deposition/crosslinking). Inspired by these events, this work establishes an approach for pseudo-reversible mechanical property modulation in synthetic hydrogels by integrating orthogonal, enzymatically triggered crosslink degradation, and light-triggered photopolymerization stiffening. Hydrogels are formed by a photo-initiated thiol-ene reaction between multiarm polyethylene glycol and a dually enzymatically degradable peptide linker, which incorporates a thrombin-degradable sequence for triggered softening and a matrix metalloproteinase (MMP)-degradable sequence for cell-driven remodeling. Hydrogels are stiffened by photopolymerization using a flexible, MMP-degradable polymer-peptide conjugate and multiarm macromers, increasing the synthetic matrix crosslink density while retaining degradability. Integration of these tools enables sequential softening and stiffening inspired by matrix remodeling events within loose connective tissues (Young's modulus (E) ≈5 to 1.5 to 6 kPa with >3x ΔE). The cytocompatibility and utility of this approach is examined with breast cancer cells, where cell proliferation shows a dependence on the timing of triggered softening. This work provides innovative tools for 3D dynamic property modulation that are synthetically accessible and cell compatible.

Comparison of National Surgical Quality Improvement Program Surgical Risk Calculator, Trauma and Injury Severity Score, and American Society of Anesthesiologists Physical Status to predict operative trauma mortality in elderly patients.

BACKGROUND: The Trauma and Injury Severity Score (TRISS) uses anatomical and physiologic variables to predict mortality. Elderly (65 years or older) trauma patients have increased mortality and morbidity for a given TRISS, in part because of functional status and comorbidities. These factors are incorporated into the American Society of Anesthesiologists Physical Status (ASA-PS) and National Surgical Quality Improvement Program Surgical Risk Calculator (NSQIP-SRC). We hypothesized scoring tools using comorbidities and functional status to be superior at predicting mortality, hospital length of stay (LOS), and complications in elderly trauma patients undergoing operation. METHODS: Four level I trauma centers prospectively collected data on elderly trauma patients undergoing surgery within 24 hours of admission. Using logistic regression, five scoring models were compared: ASA-PS, NSQIP-SRC, TRISS, TRISS-ASA-PS, and TRISS-NSQIP-SRC.Brier scores and area under the receiver operator characteristics curve were calculated to compare mortality prediction. Adjusted R2 and root mean squared error were used to compare LOS and predictive ability for number of complications. RESULTS: From 122 subjects, 9 (7.4%) died, and the average LOS was 12.9 days (range, 1-110 days). National Surgical Quality Improvement Program Surgical Risk Calculator was superior to ASA-PS and TRISS at predicting mortality (area under the receiver operator characteristics curve, 0.978 vs. 0.768 vs. 0.903; p = 0.007). Furthermore, NSQIP-SRC was more accurate predicting LOS (R2, 25.9% vs. 13.3% vs. 20.5%) and complications (R2, 34.0% vs. 22.6% vs. 29.4%) compared with TRISS and ASA-PS. Adding TRISS to NSQIP-SRC improved predictive ability compared with NSQIP-SRC alone for complications (R2, 35.5% vs. 34.0%; p = 0.046). However, adding ASA-PS or TRISS to NSQIP-SRC did not improve the predictive ability for mortality or LOS. CONCLUSION: The NSQIP-SRC, which includes comorbidities and functional status, had superior ability to predict mortality, LOS, and complications compared with TRISS alone in elderly trauma patients undergoing surgery. LEVEL OF EVIDENCE: Prognostic and Epidemiologic; Level III.

Etomidate versus ketamine for emergency endotracheal intubation: a randomized clinical trial.

PURPOSE: Etomidate and ketamine are hemodynamically stable induction agents often used to sedate critically ill patients during emergency endotracheal intubation. In 2015, quality improvement data from our hospital suggested a survival benefit at Day 7 from avoidance of etomidate in critically ill patients during emergency intubation. In this clinical trial, we hypothesized that randomization to ketamine instead of etomidate would be associated with Day 7 survival after emergency endotracheal intubation. METHODS: A prospective, randomized, open-label, parallel assignment, single-center clinical trial performed by an anesthesiology-based Airway Team under emergent circumstances at one high-volume medical center in the United States. 801 critically ill patients requiring emergency intubation were randomly assigned 1:1 by computer-generated, pre-randomized sealed envelopes to receive etomidate (0.2-0.3 mg/kg, n = 400) or ketamine (1-2 mg/kg, n = 401) for sedation prior to intubation. The pre-specified primary endpoint of the trial was Day 7 survival. Secondary endpoints included Day 28 survival. RESULTS: Of the 801 enrolled patients, 396 were analyzed in the etomidate arm, and 395 in the ketamine arm. Day 7 survival was significantly lower in the etomidate arm than in the ketamine arm (77.3% versus 85.1%, difference - 7.8, 95% confidence interval - 13, - 2.4, p = 0.005). Day 28 survival rates for the two groups were not significantly different (etomidate 64.1%, ketamine 66.8%, difference - 2.7, 95% confidence interval - 9.3, 3.9, p = 0.294). CONCLUSION: While the primary outcome of Day 7 survival was greater in patients randomized to ketamine, there was no significant difference in survival by Day 28.