Discovery of a selective and biologically active low-molecular weight antagonist of human interleukin-1ß.

Human interleukin-1ß (hIL-1ß) is a pro-inflammatory cytokine involved in many diseases. While hIL-1ß directed antibodies have shown clinical benefit, an orally available low-molecular weight antagonist is still elusive, limiting the applications of hIL-1ß-directed therapies. Here we describe the discovery of a low-molecular weight hIL-1ß antagonist that blocks the interaction with the IL-1R1 receptor. Starting from a low affinity fragment-based screening hit 1, structure-based optimization resulted in a compound (S)-2 that binds and antagonizes hIL-1ß with single-digit micromolar activity in biophysical, biochemical, and cellular assays. X-ray analysis reveals an allosteric mode of action that involves a hitherto unknown binding site in hIL-1ß encompassing two loops involved in hIL-1R1/hIL-1ß interactions. We show that residues of this binding site are part of a conformationally excited state of the mature cytokine. The compound antagonizes hIL-1ß function in cells, including primary human fibroblasts, demonstrating the relevance of this discovery for future development of hIL-1ß directed therapeutics.

Trends in Positive Surgical Margins in cT1-T2 Oral Cavity Squamous Cell Carcinoma.

OBJECTIVES/HYPOTHESIS: To evaluate trends in contemporary positive surgical margin incidence in cT1-T2 oral cavity squamous cell carcinoma and to evaluate factors associated with surgical margin status. STUDY DESIGN: Retrospective analysis of large dataset. METHODS: Retrospective analysis of the National Cancer Database. RESULTS: Between 2004 and 2016, 39,818 patients with cT1 or cT2 oral cavity squamous cell carcinoma received primary curative-intent surgery. Positive surgical margins were present in 7.95% of patients, and univariable adjusted probability of positive surgical margins over the study period declined by 1% per year (odds ratio [OR], 0.99; 95% confidence interval [CI], 0.98-1.0; P = .049). Multivariable regression revealed the annual rate of positive surgical margins declined significantly (OR, 0.95 per year; 95% CI, 0.92-0.97; P < .001). Factors associated with increased odds of positive surgical margins included cT2 disease, subsite, understaged disease, lymphovascular invasion, tumor grade, and positive lymph nodes. Race and socioeconomic status were not associated with surgical margin status. Treatment at an academic center was associated with increased time to definitive surgery (median 35 days IQR 22-50 vs. median 27 days IQR 14-42; P < .001) and a 20% reduction in positive surgical margin rate (OR, 0.80; 95% CI, 0.71-0.90; P < .001). Treatment at high-volume centers was less likely to be associated with positive surgical margins (OR, 0.85; 95% CI, 0.74-0.98; P = .02). CONCLUSION: Surgical subsite, clinical T and N category, presence of lymphovascular invasion, and histologic grade were independent predictors of positive surgical margins. Patients are increasingly being treated at high-volume and academic centers. Overall, the rate of positive surgical margins in cT1-T2 oral cavity squamous cell carcinoma is decreasing. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:1962-1970, 2022.

Gli1 Regulates the Postnatal Acquisition of Peripheral Nerve Architecture.

Peripheral nerves are organized into discrete compartments. Axons, Schwann cells (SCs), and endoneurial fibroblasts (EFs) reside within the endoneurium and are surrounded by the perineurium, a cellular sheath comprised of layers of perineurial glia (PNG). SC secretion of Desert Hedgehog (Dhh) regulates this organization. In Dhh nulls, the perineurium is deficient and the endoneurium is subdivided into small compartments termed minifascicles. Human Dhh mutations cause a neuropathy with similar defects. Here we examine the role of Gli1, a canonical transcriptional effector of hedgehog signaling, in regulating peripheral nerve organization in mice of both genders. We identify PNG, EFs, and pericytes as Gli1-expressing cells by genetic fate mapping. Although expression of Dhh by SCs and Gli1 in target cells is coordinately regulated with myelination, Gli1 expression unexpectedly persists in Dhh null EFs. Thus, Gli1 is expressed in EFs noncanonically (i.e., independent of hedgehog signaling). Gli1 and Dhh also have nonredundant activities. Unlike Dhh nulls, Gli1 nulls have a normal perineurium. Like Dhh nulls, Gli1 nulls form minifascicles, which we show likely arise from EFs. Thus, Dhh and Gli1 are independent signals: Gli1 is dispensable for perineurial development but functions cooperatively with Dhh to drive normal endoneurial development. During development, Gli1 also regulates endoneurial extracellular matrix production, nerve vascular organization, and has modest, nonautonomous effects on SC sorting and myelination of axons. Finally, in adult nerves, induced deletion of Gli1 is sufficient to drive minifascicle formation. Thus, Gli1 regulates the development and is required to maintain the endoneurial architecture of peripheral nerves.SIGNIFICANCE STATEMENT Peripheral nerves are organized into distinct cellular/ECM compartments: the epineurium, perineurium, and endoneurium. This organization, with its associated cellular constituents, is critical for the structural and metabolic support of nerves and their response to injury. Here, we show that Gli1, a transcription factor normally expressed downstream of hedgehog signaling, is required for the proper organization of the endoneurium but not the perineurium. Unexpectedly, Gli1 expression by endoneurial cells is independent of, and functions nonredundantly with, Schwann Cell-derived Desert Hedgehog in regulating peripheral nerve architecture. These results further delineate how peripheral nerves acquire their distinctive organization during normal development, and highlight mechanisms that may regulate their reorganization in pathologic settings, including peripheral neuropathies and nerve injury.

Competing stress-dependent oligomerization pathways regulate self-assembly of the periplasmic protease-chaperone DegP.

DegP is an oligomeric protein with dual protease and chaperone activity that regulates protein homeostasis and virulence factor trafficking in the periplasm of gram-negative bacteria. A number of oligomeric architectures adopted by DegP are thought to facilitate its function. For example, DegP can form a "resting" hexamer when not engaged to substrates, mitigating undesired proteolysis of cellular proteins. When bound to substrate proteins or lipid membranes, DegP has been shown to populate a variety of cage- or bowl-like oligomeric states that have increased proteolytic activity. Though a number of DegP's substrate-engaged structures have been robustly characterized, detailed mechanistic information underpinning its remarkable oligomeric plasticity and the corresponding interplay between these dynamics and biological function has remained elusive. Here, we have used a combination of hydrodynamics and NMR spectroscopy methodologies in combination with cryogenic electron microscopy to shed light on the apo-DegP self-assembly mechanism. We find that, in the absence of bound substrates, DegP populates an ensemble of oligomeric states, mediated by self-assembly of trimers, that are distinct from those observed in the presence of substrate. The oligomeric distribution is sensitive to solution ionic strength and temperature and is shifted toward larger oligomeric assemblies under physiological conditions. Substrate proteins may guide DegP toward canonical cage-like structures by binding to these preorganized oligomers, leading to changes in conformation. The properties of DegP self-assembly identified here suggest that apo-DegP can rapidly shift its oligomeric distribution in order to respond to a variety of biological insults.

Nanoengineering Approaches Toward Artificial Nose.

Significant scientific efforts have been made to mimic and potentially supersede the mammalian nose using artificial noses based on arrays of individual cross-sensitive gas sensors over the past couple decades. To this end, thousands of research articles have been published regarding the design of gas sensor arrays to function as artificial noses. Nanoengineered materials possessing high surface area for enhanced reaction kinetics and uniquely tunable optical, electronic, and optoelectronic properties have been extensively used as gas sensing materials in single gas sensors and sensor arrays. Therefore, nanoengineered materials address some of the shortcomings in sensitivity and selectivity inherent in microscale and macroscale materials for chemical sensors. In this article, the fundamental gas sensing mechanisms are briefly reviewed for each material class and sensing modality (electrical, optical, optoelectronic), followed by a survey and review of the various strategies for engineering or functionalizing these nanomaterials to improve their gas sensing selectivity, sensitivity and other measures of gas sensing performance. Specifically, one major focus of this review is on nanoscale materials and nanoengineering approaches for semiconducting metal oxides, transition metal dichalcogenides, carbonaceous nanomaterials, conducting polymers, and others as used in single gas sensors or sensor arrays for electrical sensing modality. Additionally, this review discusses the various nano-enabled techniques and materials of optical gas detection modality, including photonic crystals, surface plasmonic sensing, and nanoscale waveguides. Strategies for improving or tuning the sensitivity and selectivity of materials toward different gases are given priority due to the importance of having cross-sensitivity and selectivity toward various analytes in designing an effective artificial nose. Furthermore, optoelectrical sensing, which has to date not served as a common sensing modality, is also reviewed to highlight potential research directions. We close with some perspective on the future development of artificial noses which utilize optical and electrical sensing modalities, with additional focus on the less researched optoelectronic sensing modality.

A unified analytical theory of heteropolymers for sequence-specific phase behaviors of polyelectrolytes and polyampholytes.

The physical chemistry of liquid-liquid phase separation (LLPS) of polymer solutions bears directly on the assembly of biologically functional dropletlike bodies from proteins and nucleic acids. These biomolecular condensates include certain extracellular materials and intracellular compartments that are characterized as "membraneless organelles." Analytical theories are a valuable, computationally efficient tool for addressing general principles. LLPS of neutral homopolymers is quite well described by theory, but it has been a challenge to develop general theories for the LLPS of heteropolymers involving charge-charge interactions. Here, we present a theory that combines a random-phase-approximation treatment of polymer density fluctuations and an account of intrachain conformational heterogeneity based on renormalized Kuhn lengths to provide predictions of LLPS properties as a function of pH, salt, and charge patterning along the chain sequence. Advancing beyond more limited analytical approaches, our LLPS theory is applicable to a wide variety of charged sequences ranging from highly charged polyelectrolytes to neutral or nearly neutral polyampholytes. This theory should be useful in high-throughput screening of protein and other sequences for their LLPS propensities and can serve as a basis for more comprehensive theories that incorporate nonelectrostatic interactions. Experimental ramifications of our theory are discussed.

Refusal of Cancer-Directed Surgery in Head and Neck Squamous Cell Carcinoma Patients.

OBJECTIVES/HYPOTHESIS: To investigate the risk factors for refusal of recommended surgery in head and neck squamous cell carcinoma (HNSCC) treatment STUDY DESIGN: Retrospective review of a national database. METHODS: The Surveillance, Epidemiology, and End Results database was queried for all cases of HNSCC from 1989 to 2014. Patients who underwent recommended surgery (N = 98,270) were identified and compared to patients who refused recommended surgery (N = 3,582). Groups were compared for patient demographics, socioeconomic variables, and tumor characteristics including stage, grade, and primary site. Binary logistic regression was performed to determine independent predictors of surgery refusal. RESULTS: Of the total population, 1.8% of patients refused cancer directed surgery. Following regression, the strongest predictors of surgery refusal were found to be age greater than 75years (odds ratio [OR]: 4.23 [95% confidence interval {CI}: 3.00-5.96]), and stage III (OR: 4.19 [95% CI: 3.15-5.57]) or stage IV at diagnosis (OR: 4.49 [95% CI: 3.46-5.80]). Black race was significantly predictive (OR: 1.71 [95% CI: 1.37-2.13]) as well as marital status other than married (OR: 1.76 [95% CI: 1.49-2.07]) and Medicaid insurance status (OR:1.46 [95% CI: 1.20-1.77]). Primary site of larynx (OR: 2.01 [95% CI: 1.71-2.37]) or base of tongue (OR: 2.34 [95% CI: 1.87-2.92]) additionally predicted surgery refusal. CONCLUSIONS: A number of demographic, socioeconomic, and tumor-related variables are associated with refusal of cancer-directed surgery in head and neck squamous cell carcinoma. Recognition of these factors may help identify situations where more active education and support are needed to help patients accept optimal care. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:1368-1373, 2019.

Association of Smoking Tobacco With Complications in Head and Neck Microvascular Reconstructive Surgery.

IMPORTANCE: Smoking is a highly prevalent risk factor among patients with head and neck cancer. However, few studies have examined the association of this modifiable risk factor on postoperative outcomes following microvascular reconstruction of the head and neck. OBJECTIVE: To analyze the risk associated with smoking in patients undergoing free flap surgery of the head and neck. DESIGN, SETTING, AND PARTICIPANTS: In this retrospective, population, database study, the National Quality Improvement Program data sets from 2005 to 2014 were queried for all cases of head and neck surgery involving free flap reconstruction in the United States. The 2193 cases identified were stratified into smoking and nonsmoking cohorts and compared using χ2 and binary logistic regression analyses. Pack-years of smoking data were used to assess the degree of risk associated with a prolonged history of smoking. All analyses were conducted between January 2018 and June 2018. MAIN OUTCOMES AND MEASURES: Smoking and nonsmoking cohorts were compared for rates of demographic characteristics, comorbidities, and complications. Following correction for differences in patient demographics and comorbidities, smoking and nonsmoking cohorts were compared for rates of postoperative complications. Complication rates were further assessed within the smoking cohort by number of pack years smoked. RESULTS: Of the 2193 patients identified as having undergone free flap reconstruction of the head and neck, 624 (28.5%) had a history of recent smoking. After accounting for differences in demographic variables and patient comorbidities using regression analyses, smoking status was found to be independently associated with wound disruption (odds ratio, 1.74; 95% CI, 1.17-2.59; P = .006) and unplanned reoperation (odds ratio, 1.50; 95% CI, 1.15-1.95; P = .003). An analysis by pack-years of smoking showed that a longer smoking history was significantly associated with higher rates of numerous comorbidities but not with a corresponding increase in rates of complications. CONCLUSIONS AND RELEVANCE: Smokers undergoing free flap reconstruction of the head and neck may be at significantly higher risk of postoperative wound disruption and subsequent reoperation. These risks were independent of pack-years of smoking history, suggesting that both risks were associated with perioperative smoke exposure, and preoperative smoking cessation may be of benefit. LEVEL OF EVIDENCE: NA.

Second primary lung malignancy following head and neck squamous cell carcinoma.

OBJECTIVES/HYPOTHESIS: Analyze the characteristics of second primary lung malignancies (SPLMs) following an index head and neck squamous cell carcinoma (HNSCC). STUDY DESIGN: Retrospective cohort study. METHODS: The Surveillance, Epidemiology and End Results database was queried for all cases of HNSCC between 1973 and 2014 (N = 101,856). This population was compared to a standard population to assess relative risk for lung cancer, calculated as the standardized incidence ratio (SIR). Patients who developed SPLMs were extracted (N = 8,116) and compared to all other cases of lung cancer (N = 1,160,853) to assess histopathological differences. SPLM subpopulations divided by head and neck primary site were compared for lung cancer histology and time interval between cancer diagnoses. RESULTS: Overall, 8.0% of HNSCC patients developed SPLMs (SIR = 4.22, P < .001), diagnosed an average of 6.7 years later. Patients with HNSCC of the supraglottis and hypopharynx were at the highest risk relative to a standard population, with SIRs of 8.10 and 6.34, respectively. When comparing SPLMs to all other lung cancers, there was no difference in the distribution of lung lobe affected, but SPLMs were significantly more likely to be of squamous cell carcinoma histology (42.0% vs. 21.0%, P < .001). Among head and neck subsites, lung cancers following larynx tumors had a significantly higher proportion of small cell histology, and those following oropharyngeal or hypopharyngeal tumors had significantly higher proportions of squamous cell histology. CONCLUSIONS: Patients who undergo curative treatment of HNSCC are at high risk for developing SPLMs. Subsite-specific differences may help elucidate the degree of risk attributable to smoking, genetic susceptibility, human papillomavirus infection, or metastasis masquerading as an SPLM. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:903-909, 2019.

Measuring Solvent Hydrogen Exchange Rates by Multifrequency Excitation 15N CEST: Application to Protein Phase Separation.

Solvent exchange rates provide important information about the structural and dynamical properties of biomolecules. A large number of NMR experiments have been developed to measure such rates in proteins, the great majority of which quantify the buildup of signals from backbone amides after initial perturbation of water magnetization. Here we present a different approach that circumvents the main limitations that result from these classical hydrogen exchange NMR experiments. Building on recent developments that enable rapid recording of chemical exchange saturation transfer (CEST) pseudo-3D data sets, we describe a 15N-based CEST scheme for measurement of solvent exchange in proteins that exploits the one-bond 15N deuterium isotope shift. The utility of the approach is verified with an application to a 236 residue intrinsically disordered protein domain under conditions where it phase separates and a second application involving a mutated form of the domain that does not phase separate, establishing very similar hydrogen exchange rates for both samples. The methodology is well suited for studies of hydrogen exchange in any 15N-labeled biomolecule. A discussion of the merits of the CEST experiment in relation to the popular CLEANEX-PM scheme is presented.

Analysis of Risk Factors for Unplanned Reoperation Following Free Flap Surgery of the Head and Neck.

OBJECTIVES/HYPOTHESIS: Evaluate risk factors for unplanned reoperation following free flap surgery of the head and neck. STUDY DESIGN: Retrospective database review. METHODS: The National Surgical Quality Improvement Program database was queried for free flap surgeries of the head and neck between 2010 and 2014. Bivariate and multivariate analyses were performed to compare perioperative variables and postoperative complications in patients with and without unplanned reoperation. RESULTS: A total of 1,796 patients were identified, with an overall unplanned reoperation rate of 20.0% (n = 359) within 30 days after surgery. Upon multivariate analysis, independent preoperative risk factors for unplanned reoperation include smoking (odds ratio [OR]: 1.389, 95% confidence interval [CI]: 1.042-1.850), hypertension (OR: 1.443, 95% CI: 1.096-1.901), and prior open wound/wound infection (OR: 1.675, 95% CI: 1.123-2.499). Intraoperative risk factors include prolonged operative time (OR: 1.045, 95% CI: 1.021-1.070). Surgical site infection (OR: 6.518, 95% CI: 2.728-15.574), wound disruption (OR: 17.034, 95% CI: 8.373-34.654), blood transfusion (OR: 1.561, 95% CI: 1.062-2.296), and ventilation > 48 hours (OR: 3.626, 95% CI: 1.955-6.723) were significant postoperative predictors of unplanned reoperation. CONCLUSIONS: In patients with free flap surgeries of the head and neck, preoperative smoking, hypertension, and prior open wound/wound infection, along with prolonged operative time, are risk factors for 30-day unplanned reoperation. In addition, postoperative surgical site infection, wound disruption, blood transfusion, and ventilation >48 hours are independently associated with unplanned reoperation. LEVEL OF EVIDENCE: 4 Laryngoscope, 128:2790-2795, 2018.

Impact of Body Mass Index on Operative Outcomes in Head and Neck Free Flap Surgery.

OBJECTIVE: Analyze the risk for perioperative complications associated with body mass index (BMI) class in patients undergoing head and neck free flap reconstruction. STUDY DESIGN AND SETTING: Retrospective cohort study. SUBJECTS AND METHODS: The National Surgical Quality Improvement Program (NSQIP) database was queried for all cases of head and neck free flaps between 2005 and 2014 (N = 2187). This population was stratified into underweight, normal-weight, overweight, and obese BMI cohorts. Groups were compared for demographics, comorbidities, and procedure-related variables. Rates of postoperative complications were compared between groups using χ2 and binary logistic regression analyses. RESULTS: Underweight patients (n = 160) had significantly higher rates of numerous comorbidities, including disseminated cancer, preoperative chemotherapy, and anemia, while obese patients (n = 447) had higher rates of diabetes and hypertension. Rates of overall surgical complications, medical complications, and flap loss were insignificantly different between BMI groups. Following regression, obese BMI was protective for perioperative transfusion requirement (odds ratio [OR] = 0.63, P = .001), while underweight status conferred increased risk (OR = 2.43, P < .001). Recent weight loss was found to be an independent predictor of perioperative cardiac arrest (OR = 3.16, P = .006) while underweight BMI was not (OR = 1.21, P = .763). However, both weight loss and underweight status were associated with significantly increased risk for 30-day mortality (OR = 4.48, P = .032; OR = 4.02, P = .010, respectively). CONCLUSION: Obesity does not increase the risk for postoperative complications in head and neck free flap surgery and may be protective in some cases. When assessing a patient's fitness for surgery, underweight status or recent weight loss may suggest a reduced ability to tolerate extensive free flap reconstruction.

Probing Conformational Exchange in Weakly Interacting, Slowly Exchanging Protein Systems via Off-Resonance R1ρ Experiments: Application to Studies of Protein Phase Separation.

R1ρ relaxation dispersion experiments are increasingly used in studies of protein dynamics on the micro- to millisecond time scale. Traditional R1ρ relaxation dispersion approaches are typically predicated on changes in chemical shifts between corresponding probe spins, ΔωGE, in the interconverting states. Here, we present a new application of off-resonance 15N R1ρ relaxation dispersion that enables the quantification of slow exchange processes even in the limit where ΔωGE = 0 so long as the spins in the exchanging states have different intrinsic transverse relaxation rates (ΔR2 = R2,E - R2,G ≠ 0). In this limit, the dispersion profiles become inverted relative to those measured in the case where ΔωGE ≠ 0, ΔR2 = 0. The theoretical background to understand this effect is presented, along with a simplified exchange matrix that is valid in the limits that are germane here. An application to the study of the dynamics of the germ granule protein Ddx4 in a highly concentrated phase-separated state is described. Notably, exchange-based dispersion profiles can be obtained despite the fact that ΔωGE ≈ 0 and ΔR2 is small, ∼20-30 s-1. Our results are consistent with the formation of a significantly populated excited conformational state that displays increased contacts between adjacent protein molecules relative to the major conformer in solution, leading to a decrease in overall motion of the protein backbone. A complete set of exchange parameters is obtained from analysis of a single set of 15N off-resonance R1ρ measurements recorded at a single static magnetic field and with a single spin-lock radio frequency field strength. This new approach holds promise for studies of weakly interacting systems, especially those involving intrinsically disordered proteins that form phase-separated organelles, where little change to chemical shifts between interconverting states would be expected, but where finite ΔR2 values are observed.

Impact of diabetes on free flap surgery of the head and neck: A NSQIP analysis.

OBJECTIVE: Diabetes is associated with microvascular pathology and may predispose patients undergoing microvascular surgery to complications. This study assesses diabetes as a risk factor for complications following free flap surgery of the head and neck. PATIENTS AND METHODS: In this retrospective cohort study, data on free flap surgeries of the head and neck between 2005 and 2014 was collected from the National Surgical Quality Improvement Program (NSQIP) database. A propensity-matching algorithm (PSM) was used to equilibrate distribution of numerous covariates between the diabetic and nondiabetic cohorts. A sub-analysis was performed to examine the impact of insulin-dependency. RESULTS: The initial dataset contained 2187 free flaps of the head and neck. After implementing PSM, a new population was created containing 506 total cases with 253 DM patients. The majority of cases were male and white. The matched cohort did not contain any demographics or comorbidities associated with DM. Complications significantly elevated in the DM group were severe bleeding (P = .046), postoperative ventilation greater than 48 hours (P < .001), and pneumonia (P < .048). In patients with insulin-dependent diabetes, reintubation (P = .005), cardiac arrest (P = .010), severe bleeding (P = .006), overall surgical complications (P = .015), and overall complications (P = .005) were significantly increased. CONCLUSION: This study examines the impact of diabetes on postoperative complications following free flap reconstruction of the head and neck. Propensity score matching was utilized. Analysis of the PSM cohort suggests that diabetic patients have elevated rates of postoperative pulmonary complications. Additionally, patients with insulin-dependent diabetes have significantly elevated rates of medical and surgical complications.

Association of Anesthesia Duration With Complications After Microvascular Reconstruction of the Head and Neck.

IMPORTANCE: Prolonged anesthesia and operative times have deleterious effects on surgical outcomes in a variety of procedures. However, data regarding the influence of anesthesia duration on microvascular reconstruction of the head and neck are lacking. OBJECTIVE: To examine the association of anesthesia duration with complications after microvascular reconstruction of the head and neck. DESIGN, SETTING, AND PARTICIPANTS: The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database was used to collect data. In total, 630 patients who underwent head and neck microvascular reconstruction were recorded in the NSQIP registry from January 1, 2005, through December 31, 2013. Patients who underwent microvascular reconstructive surgery performed by otolaryngologists or plastic surgeons were included in this study. Data analysis was performed from October 15, 2015, to January 15, 2016. EXPOSURES: Microvascular reconstructive surgery of the head and neck. MAIN OUTCOMES AND MEASURES: Patients were stratified into 5 quintiles based on mean anesthesia duration and analyzed for patient characteristics and operative variables (mean [SD] anesthesia time: group 1, 358.1 [175.6] minutes; group 2, 563.2 [27.3] minutes; group 3, 648.9 [24.0] minutes; group 4, 736.5 [26.3] minutes; and group 5, 922.1 [128.1] minutes). Main outcomes include rates of postoperative medical and surgical complications and mortality. RESULTS: A total of 630 patients undergoing head and neck free flap surgery had available data on anesthesia duration and were included (mean [SD] age, 61.6 [13.8] years; 436 [69.3%] male). Bivariate analysis revealed that increasing anesthesia duration was associated with increased 30-day complications overall (55 [43.7%] in group 1 vs 80 [63.5%] in group 5, P = .006), increased 30-day postoperative surgical complications overall (45 [35.7%] in group 1 vs 78 [61.9%] in group 5, P < .001), increased rates of postoperative transfusion (32 [25.4%] in group 1 vs 70 [55.6%] in group 5, P < .001), and increased rates of wound disruption (0 in group 1 vs 10 [7.9%] in group 5, P = .02). No specific medical complications and no overall medical complication rate (24 [19.0%] in group 1 vs 22 [17.5%] in group 5, P = .80) or mortality (1 [0.8%] in group 1 vs 1 [0.8%] in group 5, P = .75) were associated with increased anesthesia duration. On multivariate analysis accounting for demographics and significant preoperative factors including free flap type, overall complications (group 5: odds ratio [OR], 1.98; 95% CI, 1.10-3.58; P = .02), surgical complications (group 5: OR, 2.46; 95% CI, 1.35-4.46; P = .003), and postoperative transfusion (group 5: OR, 2.31; 95% CI, 1.27-4.20; P = .006) remained significantly associated with increased anesthesia duration; the association of wound disruption and increased anasthesia duration was nonsignificant (group 5: OR, 2.0; 95% CI, 0.75-5.31; P = .16). CONCLUSIONS AND RELEVANCE: Increasing anesthesia duration was associated with significantly increased rates of surgical complications, especially the requirement for postoperative transfusion. Rates of medical complications were not significantly altered, and overall mortality remained unaffected. Avoidance of excessive blood loss and prolonged anesthesia time should be the goal when performing head and neck free flap surgery. LEVEL OF EVIDENCE: 3.

The role of elective neck dissection in the treatment of maxillary sinus squamous cell carcinoma.

OBJECTIVE: This study is designed to analyze the survival benefits of elective neck dissection (END) in the treatment of squamous cell carcinoma of the maxillary sinus (MS-SCC) with clinically negative neck lymph nodes (N0) and no metastasis (M0). STUDY DESIGN: The aim of this study was to evaluate whether END improves survival in patients with MS-SCC. METHODS: This study is a population-based, concurrent retrospective database analysis of patients diagnosed with N0M0 MS-SCC from 2004 to 2013. Data were acquired from the Surveillance, Epidemiology, and End Results database. Frequency functions, Kaplan-Meier and Cox regression models were queried to analyze demographics, treatment status, and survival outcomes. RESULTS: There were a total of 927 MS-SCC cases in the database between 2004 and 2013. This analysis revealed that for the overall cohort, END significantly and independently reduces the 5-year hazard of death in MS-SCC (hazard ratio [HR] = 0.646, 95% confidence interval [CI] = 0.419-0.873, P = 0.047). For early tumor (T)1/T2 tumors and T4 tumors, END did not independently improve 5-year survival. However, for T3 disease, END significantly reduced the 5-year hazard of death in MS-SCC (HR = 0.471, 95% CI = 0.261-0.680, P = 0.001), regardless of other covariates, including adjuvant radiation. There has been an increase in the percentage of MS-SCC surgeries that have been accompanied by END since SEER started collecting this data, although this did not demonstrate significance (R2 = 0.622). CONCLUSION: END improves disease-specific survival in patients with MS-SCC size > 4 cm and advanced T-stage (American Joint Committee on Cancer AJCC TIII). Therefore, surgeons performing maxillectomies should consider conducting an END concurrent with maxillectomy for those with size > 4 cm advanced stage cancer. LEVEL OF EVIDENCE: 4. Laryngoscope, 1835-1841, 2018.

Structural and hydrodynamic properties of an intrinsically disordered region of a germ cell-specific protein on phase separation.

Membrane encapsulation is frequently used by the cell to sequester biomolecules and compartmentalize their function. Cells also concentrate molecules into phase-separated protein or protein/nucleic acid "membraneless organelles" that regulate a host of biochemical processes. Here, we use solution NMR spectroscopy to study phase-separated droplets formed from the intrinsically disordered N-terminal 236 residues of the germ-granule protein Ddx4. We show that the protein within the concentrated phase of phase-separated Ddx4, [Formula: see text], diffuses as a particle of 600-nm hydrodynamic radius dissolved in water. However, NMR spectra reveal sharp resonances with chemical shifts showing [Formula: see text] to be intrinsically disordered. Spin relaxation measurements indicate that the backbone amides of [Formula: see text] have significant mobility, explaining why high-resolution spectra are observed, but motion is reduced compared with an equivalently concentrated nonphase-separating control. Observation of a network of interchain interactions, as established by NOE spectroscopy, shows the importance of Phe and Arg interactions in driving the phase separation of Ddx4, while the salt dependence of both low- and high-concentration regions of phase diagrams establishes an important role for electrostatic interactions. The diffusion of a series of small probes and the compact but disordered 4E binding protein 2 (4E-BP2) protein in [Formula: see text] are explained by an excluded volume effect, similar to that found for globular protein solvents. No changes in structural propensities of 4E-BP2 dissolved in [Formula: see text] are observed, while changes to DNA and RNA molecules have been reported, highlighting the diverse roles that proteinaceous solvents play in dictating the properties of dissolved solutes.

Pediatric head and neck bone sarcomas: An analysis of 204 cases.

OBJECTIVES: To analyze the demographics, survival, and treatment efficacy of pediatric sarcomas of the facial skeleton and skull. METHODS: Retrospective study of cases from the US National Cancer Institute's Surveillance, Epidemiology, and End Results database. Pediatric patients between the ages of 0 and 18 diagnosed with a malignant sarcoma of either the mandible or the bones of skull, face, and associated joints from 1973 to 2013 were studied. RESULTS: In total, 204 patients were included in the analysis. The average age at diagnosis was 11.39 (±5.15) years with a male-to-female ratio of 1.4:1. Whites were the most commonly affected race (76.0%). Malignant mandible sarcomas accounted for 29.9% of the cohort (n = 61). The most common pathology was osteosarcoma, which accounted for 43.6% of the cohort (n = 89). Among patients with known histologic grade (n = 95), 26.0% were AJCC stage III or IV. Overall, 5-year disease-specific survival (DSS) was 80.6%. When stratified by treatment modality, 5-year DSS was 86.0% for surgery alone, 67.9% for radiation alone, and 75.3% for surgery with adjuvant radiotherapy (p = 0.041). CONCLUSIONS: Osteosarcoma, Ewing's sarcoma, and chondrosarcoma are the most common subtypes of pediatric head and neck bone sarcoma. Such sarcomas more commonly affect whites and males during pubertal ages. Disease-specific survival is not affected by primary site. Surgery alone is the mainstay of treatment, and demonstrates higher 5-year disease-specific survival compared to radiotherapy alone. Adjuvant radiotherapy does not seem to increase survival, but further investigation is warranted.

An enhanced sensitivity methyl 1H triple-quantum pulse scheme for measuring diffusion constants of macromolecules.

We present a pulse scheme that exploits methyl 1H triple-quantum (TQ) coherences for the measurement of diffusion rates of slowly diffusing molecules in solution. It is based on the well-known stimulated echo experiment, with encoding and decoding of TQ coherences. The size of quantifiable diffusion coefficients is thus lowered by an order of magnitude with respect to single-quantum (SQ) approaches. Notably, the sensitivity of the scheme is high, approximately ¾ that of the corresponding single quantum experiment, neglecting relaxation losses, and on the order of a factor of 4 more sensitive than a previously published sequence for AX3 spin systems (Zheng et al. in JMR 198:271-274, 2009) for molecules that are only 13C labeled at the methyl carbon position. Diffusion coefficients measured from TQ- and SQ-based experiments recorded on a range of protein samples are in excellent agreement. We present an application of this technique to the study of phase-separated proteins where protein concentrations in the condensed phase can exceed 400 mg/mL, diffusion coefficients can be as low as ~10-9 cm2s-1 and traditional SQ experiments fail.