Structure of FUS Protein Fibrils and Its Relevance to Self-Assembly and Phase Separation of Low-Complexity Domains.

Polymerization and phase separation of proteins containing low-complexity (LC) domains are important factors in gene expression, mRNA processing and trafficking, and localization of translation. We have used solid-state nuclear magnetic resonance methods to characterize the molecular structure of self-assembling fibrils formed by the LC domain of the fused in sarcoma (FUS) RNA-binding protein. From the 214-residue LC domain of FUS (FUS-LC), a segment of only 57 residues forms the fibril core, while other segments remain dynamically disordered. Unlike pathogenic amyloid fibrils, FUS-LC fibrils lack hydrophobic interactions within the core and are not polymorphic at the molecular structural level. Phosphorylation of core-forming residues by DNA-dependent protein kinase blocks binding of soluble FUS-LC to FUS-LC hydrogels and dissolves phase-separated, liquid-like FUS-LC droplets. These studies offer a structural basis for understanding LC domain self-assembly, phase separation, and regulation by post-translational modification.

Atrial fibrillation ablation in heart failure patients: Where do we stand in 2023? - State of the art review.

Atrial fibrillation (AF) and heart failure are common overlapping cardiovascular disorders. Despite important therapeutic advances over the past several decades, controversy persists about whether a rate control or rhythm control approach constitutes the best option in this population. There is also considerable debate about whether antiarrhythmic drug therapy or ablation is the best approach when rhythm control is pursued.  A brief historical examination of the literature addressing this issue will be performed. An analysis of several important clinical outcomes observed in the prospective, randomized studies, which have compared AF ablation to non-ablation treatment options, will be discussed. This review will conclude with recommendations to guide clinicians on the status of AF ablation as a treatment option when considering management options in heart failure patients with atrial fibrillation.

Molecular structure of a prevalent amyloid-ß fibril polymorph from Alzheimer's disease brain tissue.

Amyloid-ß (Aß) fibrils exhibit self-propagating, molecular-level polymorphisms that may contribute to variations in clinical and pathological characteristics of Alzheimer's disease (AD). We report the molecular structure of a specific fibril polymorph, formed by 40-residue Aß peptides (Aß40), that is derived from cortical tissue of an AD patient by seeded fibril growth. The structure is determined from cryogenic electron microscopy (cryoEM) images, supplemented by mass-per-length (MPL) measurements and solid-state NMR (ssNMR) data. Previous ssNMR studies with multiple AD patients had identified this polymorph as the most prevalent brain-derived Aß40 fibril polymorph from typical AD patients. The structure, which has 2.8-Å resolution according to standard criteria, differs qualitatively from all previously described Aß fibril structures, both in its molecular conformations and its organization of cross-ß subunits. Unique features include twofold screw symmetry about the fibril growth axis, despite an MPL value that indicates three Aß40 molecules per 4.8-Å ß-sheet spacing, a four-layered architecture, and fully extended conformations for molecules in the central two cross-ß layers. The cryoEM density, ssNMR data, and MPL data are consistent with ß-hairpin conformations for molecules in the outer cross-ß layers. Knowledge of this brain-derived fibril structure may contribute to the development of structure-specific amyloid imaging agents and aggregation inhibitors with greater diagnostic and therapeutic utility.

Fellowship-Trained Surgeons Experience a Learning Curve Performing Revision Total Joint Arthroplasty.

BACKGROUND: Revision total hip arthroplasty (rTHA) and revision total knee arthroplasty (rTKA) require considerable surgical proficiency, but are frequently delegated to the least experienced surgeons. This study examined the influence of surgeon experience on revision outcomes. METHODS: Prospective data on confirmed aseptic rTHAs (n = 122) and rTKAs (n = 195) performed by 4 fellowship-trained surgeons in the same practice were retrospectively analyzed. Surgeons were grouped based on years in practice (inexperienced [IE] first 2 years, early experience [EE] 4 to 6 years, and senior experience [SE] 15 to 17 years). Procedure duration, estimated blood loss (EBL), and reoperation rates were compared, controlling for potential covariates. RESULTS: Procedure durations varied based on surgeon experience for 3 of 4 rTHA diagnoses (P ≤ 0.001). Relative to the SE surgeon, procedure duration was 80.0 (95% confidence interval 61.7 to 98.4, P < 0.001) minutes longer for IE surgeons and 30.9 (95% confidence interval 17.5 to 44.3, P < 0.001) minutes longer for the EE surgeon. Procedure durations also varied based on surgeon experience for 3 of 4 rTKA diagnoses (P < 0.001), with the longest durations for IE surgeons. Procedure durations varied based on the interaction of surgeon experience, patient age, and body mass index. The EBL did not differ in rTHA based on surgeon experience (P = 0.978), but did differ for rTKA (P = 0.004). There were 25% of rTHAs performed by IE surgeons compared to 15.5% for the EE surgeon and 3.6% for the SE surgeon that underwent reoperation within a year of the index procedure (P = 0.064), with significantly more reoperations for the same indication among IE and EE surgeons (P = 0.046). CONCLUSIONS: Complex procedures completed by less experienced surgeons may result in longer procedures, higher EBL, and more early reoperations. Study findings implicate a learning curve for revision arthroplasty that continues for several years, warranting consideration of existing patient allocation and referral patterns.

Differential contribution of alpha and beta cell dysfunction to impaired fasting glucose and impaired glucose tolerance.

AIMS/HYPOTHESIS: People with isolated impaired fasting glucose (IFG) have normal beta cell function. We hypothesised that an increased glucose threshold for beta cell secretion explains IFG. METHODS: We used graded glucose infusion to examine the relationship of insulin secretion rate (ISR) and glucagon secretion rate (GSR) with rising glucose. We studied 39 non-diabetic individuals (53 ± 2 years, BMI 30 ± 1 kg/m2), categorised by fasting glucose and glucose tolerance status. After an overnight fast, a variable insulin infusion was used to maintain glucose at ~4.44 mmol/l (07:00 to 08:30 hours). At 09:00 hours, graded glucose infusion commenced at 1 mg kg-1 min-1 and doubled every 60 min until 13:00 hours. GSR and ISR were calculated by nonparametric deconvolution from concentrations of glucagon and C-peptide, respectively. RESULTS: The relationship of ISR with glucose was linear and the threshold for insulin secretion in isolated IFG did not differ from that in people with normal fasting glucose and normal glucose tolerance. GSR exhibited a single-exponential relationship with glucose that could be characterised by G50, the change in glucose necessary to suppress GSR by 50%. G50 was increased in IFG compared with normal fasting glucose regardless of the presence of impaired or normal glucose tolerance. CONCLUSIONS/INTERPRETATION: These data show that, in non-diabetic humans, alpha cell dysfunction contributes to the pathogenesis of IFG independently of defects in insulin secretion. We also describe a new index that quantifies the suppression of glucagon secretion by glucose.

Effects of acute changes in fasting glucose and free fatty acid concentrations on indices of ß-cell function and glucose metabolism in subjects without diabetes.

Elevated fasting free fatty acids (FFAs) and fasting glucose are additively associated with impaired glucose tolerance (IGT) and decreased ß-cell function [quantified as disposition index (DI)]. We sought to examine how changes in fasting FFA and glucose alter islet function. We studied 10 subjects with normal fasting glucose (NFG) and normal glucose tolerance (NGT) on two occasions. On one occasion, Intralipid and glucose were infused overnight to mimic conditions present in IFG/IGT. In addition, we studied seven subjects with IFG/IGT on two occasions. On one occasion, insulin was infused to lower overnight FFA and glucose concentrations to those observed in people with NFG/NGT. The following morning, a labeled mixed meal was used to measure postprandial glucose metabolism and ß-cell function. Elevation of overnight fasting FFA and glucose in NFG/NGT did not alter peak or integrated glucose concentrations (2.0 ± 0.1 vs. 2.0 ± 0.1 Mol per 5 h, Saline vs. Intralipid/glucose, P = 0.55). Although overall ß-cell function quantified by the Disposition Index was unchanged, the dynamic component of ß-cell responsivity (ϕd) was decreased by Intralipid and glucose infusion (9 ± 1 vs. 16 ± 3 10-9, P = 0.02). In people with IFG/IGT, insulin did not alter postprandial glucose concentrations or indices of ß-cell function. Endogenous glucose production and glucose disappearance were also unchanged in both groups. We conclude that acute, overnight changes in FFA, and glucose concentrations do not alter islet function or glucose metabolism in prediabetes.NEW & NOTEWORTHY This experiment studied the effect of changes in overnight concentrations of free fatty acids (FFAs) and glucose on ß-cell function and glucose metabolism. In response to elevation of these metabolites, the dynamic component of the ß-cell response to glucose was impaired. This suggests that in health overnight hyperglycemia and FFA elevation can deplete preformed insulin granules in the ß-cell.

Inadequate Rectal Pressure and Insufficient Relaxation and Abdominopelvic Coordination in Defecatory Disorders.

BACKGROUND & AIMS: Diagnostic tests for defecatory disorders (DDs) asynchronously measure anorectal pressures and evacuation and show limited agreement; thus, abdominopelvic-rectoanal coordination in normal defecation and DDs is poorly characterized. We aimed to investigate anorectal pressures, anorectal and abdominal motion, and evacuation simultaneously in healthy and constipated women. METHODS: Abdominal wall and anorectal motion, anorectal pressures, and rectal evacuation were measured simultaneously with supine magnetic resonance defecography and anorectal manometry. Evacuators were defined as those who attained at least 25% rectal evacuation. Supervised (logistic regression and random forest algorithm) and unsupervised (k-means cluster) analyses identified abdominal and anorectal variables that predicted evacuation. RESULTS: We evaluated 28 healthy and 26 constipated women (evacuators comprised 19 healthy participants and 8 patients). Defecation was initiated by abdominal wall expansion that was coordinated with anorectal descent, increased rectal and anal pressure, and then anal relaxation and rectal evacuation. Compared with evacuators, nonevacuators had lower anal diameters during simulated defecation, rectal pressure, anorectal junction descent, and abdominopelvic-rectoanal coordination (P < .05). Unsupervised cluster analysis identified 3 clusters that were associated with evacuator status (P < .01), that is, 10 evacuators (83%), 16 evacuators (73%), and 1 evacuator (5%) in clusters 1, 2, and 3, respectively. Each cluster had distinct characteristics (eg, maximum abdominosacral distance, rectal pressure, anorectal junction descent, anal diameter) and correlates that were more (clusters 1-2) or less (cluster 3) conducive to evacuation. Cluster 2 had 16 evacuators (73%) and intermediate characteristics (eg, lower anal resting pressure and relaxation during evacuation; P < .05). CONCLUSIONS: Women with DDs and a modest proportion of healthy women had specific patterns of anorectal dysfunction, including inadequate rectal pressurization, anal relaxation, and abdominopelvic-rectoanal coordination. These observations may guide individualized therapy for DDs in the future.

Comparison of Anorectal Manometry, Rectal Balloon Expulsion Test, and Defecography for Diagnosing Defecatory Disorders.

BACKGROUND & AIMS: The utility of high-resolution anorectal manometry (HR-ARM) for diagnosing defecatory disorders (DDs) is unclear because healthy people may have features of dyssynergia. We aimed to identify objective diagnostic criteria for DD and to ascertain the utility of HR-ARM for diagnosing DD. METHODS: Constipated patients were assessed with HR-ARM and rectal balloon expulsion time (BET), and a subset underwent defecography. Normal values were established by assessing 184 sex-matched healthy individuals. Logistic regression models evaluated the association of abnormal HR-ARM findings with prolonged BET and reduced rectal evacuation (determined by defecography). RESULTS: A total of 474 constipated individuals (420 women) underwent HR-ARM and BET, and 158 underwent defecography. BET was prolonged, suggesting a DD, for 152 patients (32%). Rectal evacuation was lower for patients with prolonged vs normal BET. A lower rectoanal gradient during evacuation, reduced anal squeeze increment, and reduced rectal sensation were independently associated with abnormal BETs; the rectoanal gradient was 36% sensitive and 85% specific for prolonged BET. A lower rectoanal gradient and prolonged BET were independently associated with reduced evacuation. Among constipated patients, the probability of reduced rectal evacuation was 14% when the gradient and BET were both normal, 45% when either was abnormal, and 75% when both variables were abnormal. CONCLUSIONS: HR-ARM, BET, and defecography findings were concordant for constipated patients, and reduced rectoanal gradient was the best HR-ARM predictor of prolonged BET or reduced rectal evacuation. Prolonged BET, reduced gradient, and reduced evacuation each independently supported a diagnosis of DD in constipated patients. We propose the terms probable DD for patients with an isolated abnormal gradient or BET and definite DD for patients with abnormal results from both tests.

Sex-based differences in metabolic protection by the ANP genetic variant rs5068 in the general population.

Atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) are produced in the heart and secreted into the circulation. As hormones, both peptides activate the guanylyl cyclase receptor A (GC-A), playing a role in blood pressure (BP) regulation. A significant role for ANP and BNP includes favorable actions in metabolic homeostasis. Sex-based high prevalence of risk factors for cardiovascular disease in males compared with females is well established, but sex-based differences on cardiometabolic protection have not been investigated in relation to ANP (NPPA) and BNP (NPPB) gene variants. We included 1,146 subjects in the general population from Olmsted County, Minnesota. Subjects were genotyped for the ANP gene variant rs5068 and BNP gene variant rs198389. Cardiometabolic parameters and medical records were reviewed. In the presence of the minor allele of rs5068, diastolic BP, creatinine, body mass index (BMI), waist measurement, insulin, and prevalence of obesity and metabolic syndrome were lower, whereas HDL was higher in males with only trends observed in females. We observed no associations of the minor allele with echocardiographic parameters in either males or females. Regarding rs198389 genotype, the minor allele was not associated with any BP, metabolic, renal, or echocardiographic parameters in either sex. In the general community, the minor allele of the ANP gene variant rs5068 is associated with a favorable metabolic phenotype in males. No associations were observed with the BNP gene variant rs198389. These studies support a protective role of the ANP pathway on metabolic function and underscore the importance of sex in relationship to natriuretic peptide responses.NEW & NOTEWORTHY Males are characterized by lower ANP and BNP with greater prevalence of cardiometabolic disease. The ANP genetic variant rs5068 was associated with less metabolic dysfunction in males, whereas no metabolic profile was related to the BNP genetic variant rs198389 in the general population. ANP may play a more biological role in metabolic homeostasis compared with BNP in the general population with greater physiological metabolic actions in males compared with females.

Legal Firearm Sales at State Level and Rates of Violent Crime, Property Crime, and Homicides.

INTRODUCTION: The effects of firearm sales and legislation on crime and violence are intensely debated, with multiple studies yielding differing results. We hypothesized that increased lawful firearm sales would not be associated with the rates of crime and homicide when studied using a robust statistical method. METHODS: National and state rates of crime and homicide during 1999-2015 were obtained from the United States Department of Justice and the Centers for Disease Control and Prevention. National Instant Criminal Background Check System background checks were used as a surrogate for lawful firearm sales. A general multiple linear regression model using log event rates was used to assess the effect of firearm sales on crime and homicide rates. Additional modeling was then performed on a state basis using an autoregressive correlation structure with generalized estimating equation estimates for standard errors to adjust for the interdependence of variables year to year within a particular state. RESULTS: Nationally, all crime rates except the Centers for Disease Control and Prevention-designated firearm homicides decreased as firearm sales increased over the study period. Using a naive national model, increases in firearm sales were associated with significant decreases in multiple crime categories. However, a more robust analysis using generalized estimating equation estimates on state-level data demonstrated increases in firearms sales were not associated with changes in any crime variables examined. CONCLUSIONS: Robust analysis does not identify an association between increased lawful firearm sales and rates of crime or homicide. Based on this, it is unclear if efforts to limit lawful firearm sales would have any effect on rates of crime, homicide, or injuries from violence committed with firearms.

Abdomino-anal Dyscoordination in Defecatory Disorders.

BACKGROUND & AIMS: The contribution of the abdominal muscles to normal defecation and disturbances thereof in defecatory disorders (DDs) are unknown. METHODS: In 30 healthy and 60 constipated women with normal rectal balloon expulsion time (BET) (n = 26) or prolonged BET (ie, DD; n = 34), seated anorectal pressures (manometry) and thickness (ultrasound) of the external and internal oblique and transversus abdominis muscles were measured simultaneously at rest, during hollowing, squeeze, evacuation, and a Valsalva maneuver. RESULTS: Compared with healthy women with a normal BET, DD women had a lower rectal and greater anal pressure increase during evacuation (P ≤ .05), and more activation of the internal oblique and the transversus abdominis muscles during squeeze (P < .05). The change in transversus abdominis thickness during a Valsalva maneuver vs hollowing (rho = 0.5; P = .002) and separately vs evacuation (rho = 0.7; P < .0001) were correlated in DD but not in healthy women with a normal BET. A principal component (PC) analysis of anorectal pressures and muscle thicknesses during evacuation uncovered a PC (PC3) that was associated with a prolonged BET. Higher PC3 scores were associated with low rectal and high anal pressures at rest and during evacuation, thinner external oblique muscle, and thicker internal oblique muscle during evacuation. A greater PC3 score was associated with increased odds for DD vs health (odds ratio, 1.84; 95% CI, 1.05-3.23), and separately vs constipation with a normal BET (odds ratio, 3.64; 95% CI, 1.73-7.69). CONCLUSIONS: Taken together, these findings show 3, possibly inter-related, disturbances suggestive of dyscoordination in DD: aberrant activation of abdominal muscles during squeeze in DD, dyscoordination of the abdominal muscles during various tasks in constipated women, and abdomino-anal dyscoordination.

A pragmatic clinical trial of cascade testing for familial hypercholesterolemia.

PURPOSE: We compared new cases detected per index case in familial hypercholesterolemia (FH) families with or without an identifiable monogenic etiology. METHODS: We enrolled 52 FH probands with a pathogenic variant (FHg+) in LDLR, APOB, or PCSK9 and 73 probands without such a variant (FHg-). After direct contact by the study team, family members (FMs) of FHg+ probands could opt-in for genetic testing and FMs of FHg- probands were asked to provide a lipid profile. New cases were defined as presence of a pathogenic variant in FHg+ families and as low-density lipoprotein cholesterol ≥155 mg/dL in FHg- families. RESULTS: Of 71 FHg+ probands seen by a genetic counselor, 52 consented and identified 253 FMs (111 consented and were tested, yielding 48 new cases). Of 101 FHg- probands who received counseling, 73 consented and identified 295 FMs (63 consented and were tested, yielding 17 new cases). New case detection per index case was significantly greater in FHg+ than in FHg- families (0.92 vs 0.23), a result of higher cascade testing uptake (43.9 vs 21.4%) and yield (43.2 vs 27.0%) in the former. CONCLUSION: New case detection rate was significantly higher in FH families with a monogenic etiology than in those without such an etiology owing to greater uptake and yield of cascade testing.

Novel segmentation algorithm for high-throughput analysis of spectral domain-optical coherence tomography imaging of teleost retinas.

Spectral domain-optical coherence tomography (SD-OCT) has become an essential tool for assessing ocular tissues in live subjects and conducting research on ocular development, health, and disease. The processing of SD-OCT images, particularly those from non-mammalian species, is a labor-intensive manual process due to a lack of automated analytical programs. This paper describes the development and implementation of a novel computer algorithm for the quantitative analysis of SD-OCT images of live teleost eyes. Automated segmentation processing of SD-OCT images of retinal layers was developed using a novel algorithm based on thresholding. The algorithm measures retinal thickness characteristics in a large volume of imaging data of teleost ocular structures in a short time, providing increased accuracy and repeatability of SD-OCT image analysis over manual measurements. The algorithm also generates hundreds of retinal thickness measurements per image for a large number of images for a given dataset. Meanwhile, heat mapping software that plots SD-OCT image measurements as a color gradient was also created. This software directly converts the measurements of each processed image to represent changes in thickness across the whole retinal scan. It also enables 2D and 3D visualization of retinal thickness across the scan, facilitating specimen comparison and localization of areas of interest. The study findings showed that the novel algorithm is more accurate, reliable, and repeatable than manual SD-OCT analysis. The adaptability of the algorithm makes it potentially suitable for analyzing SD-OCT scans of other non-mammalian species.

Treatment of Toxin-Related Status Epilepticus With Levetiracetam, Fosphenytoin, or Valproate in Patients Enrolled in the Established Status Epilepticus Treatment Trial.

STUDY OBJECTIVE: We describe a subset of patients with toxin-related precipitants of seizures/status epilepticus enrolled in the Established Status Epilepticus Treatment Trial (ESETT). METHODS: The ESETT was a prospective, double-blinded, adaptive trial evaluating levetiracetam, valproate, and fosphenytoin as second-line agents in benzodiazepine-refractory status epilepticus in adults and children. The primary outcome was the absence of seizures and improvement in the level of consciousness 1 hour after study drug administration. In this post hoc analysis, the safety and efficacy of second-line agents in a subset of patients with toxin-related seizures are described. RESULTS: A total of 249 adults and 229 children were enrolled in the ESETT. Toxin-related seizures occurred in 29 (11.6%) adults and 1 child (0.4%). In adults, men were more likely to have toxin-related seizures than women (25 of 145, 17.2% versus 4 of 104, 3.9%). The most common toxin-related precipitants were alcohol withdrawal and cocaine, 11(37%) of 30 patients each. Cocaine was used with other substances by most patients 10 (91%) of 11, most commonly with an opioid 7 (64%) of 11. For alcohol withdrawal-related seizures, treatment successes with levetiracetam, valproate, and fosphenytoin were 3 (100%) of 3, 3 (50%) of 6, and 1 (50%) of 2, respectively. For cocaine-related seizures, treatment success was 1 (14%) of 7 for levetiracetam, 0 (0%) of 1 for valproate, and 1 (33%) of 3 for fosphenytoin. One patient who used cocaine and an opioid received fosphenytoin and developed life-threatening hypotension. CONCLUSION: In the ESETT, approximately 1 in 10 adult patients with status epilepticus presented with a toxin-related seizure. Alcohol withdrawal and cocaine/opioid use were the most common toxin-related precipitants. Toxin-related benzodiazepine-refractory status epilepticus was successfully treated with a single dose of second-line antiseizure medication in 42% of the patients.

Clinical outcomes of first- and second-generation hydrogel coils compared with bare platinum coils: a systematic literature review.

Endovascular coiling has revolutionized intracranial aneurysm treatment; however, recurrence continues to represent a major limitation. The hydrogel coil was developed to increase packing density and improve neck healing and therefore decrease recurrence rates. In this paper, we review treatment outcomes of first- (1HCs) and second-generation (2HCs) hydrogel coils and compare them to those of bare platinum coils (BPC). A query of multiple databases was performed. Articles with at least 10 aneurysms treated with either 1HC or 2HC were selected for analysis. Collected data included aneurysm size, rupture status, initial occlusion, initial residual neck/aneurysm, packing density, mortality, morbidity, recurrence, and retreatment rates. The primary endpoint was recurrence at final follow-up. Secondary endpoints included residual neck and dome rates as well as procedure-related complications and functional dependence at final follow-up. Studies that compared 1HC to BPC showed significant lower recurrence (24% vs. 30.8%, p = 0.02) and higher packing density (58.5% vs. 24.1%, p < 0.001) in 1HC but no significant difference in initial occlusion rate (p = 0.08). Studies that compared 2HC to BPC showed lower recurrence (6.3% vs. 14.3%, p = 0.007) and retreatment rates (3.4% vs. 7.7%, p = 0.010) as well as higher packing density (36.4% vs. 29.2%, p = 0.002) in 2HC, with similar initial occlusion rate (p = 0.86). The rate of complications was not statistically different between HC (25.5%) and BPC (22.6%, p = 0.06). Based on our review, the 1HC and 2HC achieved higher packing density and lower recurrence rates compared to BPC. The safety profile was similar between both groups.

Application of millisecond time-resolved solid state NMR to the kinetics and mechanism of melittin self-assembly.

Common experimental approaches for characterizing structural conversion processes such as protein folding and self-assembly do not report on all aspects of the evolution from an initial state to the final state. Here, we demonstrate an approach that is based on rapid mixing, freeze-trapping, and low-temperature solid-state NMR (ssNMR) with signal enhancements from dynamic nuclear polarization (DNP). Experiments on the folding and tetramerization of the 26-residue peptide melittin following a rapid pH jump show that multiple aspects of molecular structure can be followed with millisecond time resolution, including secondary structure at specific isotopically labeled sites, intramolecular and intermolecular contacts between specific pairs of labeled residues, and overall structural order. DNP-enhanced ssNMR data reveal that conversion of conformationally disordered melittin monomers at low pH to α-helical conformations at neutral pH occurs on nearly the same timescale as formation of antiparallel melittin dimers, about 6 to 9 ms for 0.3 mM melittin at 24 °C in aqueous solution containing 20% (vol/vol) glycerol and 75 mM sodium phosphate. Although stopped-flow fluorescence data suggest that melittin tetramers form quickly after dimerization, ssNMR spectra show that full structural order within melittin tetramers develops more slowly, in ∼60 ms. Time-resolved ssNMR is likely to find many applications to biomolecular structural conversion processes, including early stages of amyloid formation, viral capsid formation, and protein-protein recognition.

Procedure Duration, Time Under Anesthesia, and Readmissions in Direct Anterior and Posterior Approach Total Hip Arthroplasty.

BACKGROUND: Operative time is related to complications in primary total hip arthroplasty (THA). This study compared operative time in direct anterior (DA) and posterior approach THA and whether differences were related to increased hospital readmissions within 90 days of discharge. METHODS: Prospectively documented data on 3,152 consecutively performed THAs by 16 surgeons at a large Midwestern United States academic healthcare system were retrospectively reviewed. All surgeons were beyond their learning curve. Cases characterized by factors extending operative time were excluded. A total of 1,235 analysis cases were performed with the DA approach and 1,608 with the posterior approach. DA patients had lower mean body mass index (P < .001), were more likely to be classified as American Society of Anesthesiologists Physical Status 1 or 2 (P < .001), and more likely to have surgery in an ambulatory setting (P < .001). RESULTS: Time under anesthesia was significantly longer for DA procedures by 19 to 27 minutes in hospital and ambulatory settings, respectively (P < .001). Increasing body mass index had a greater impact on anesthesia time for DA patients (P = .020). There were no differences in nontraumatic readmissions within 90 days of surgery based on surgical approach (P ≥ .480); however, significantly more DA patients classified as ASA-PS 3 or 4 were readmitted compared to those classified as ASA-PS 1 or 2 (P < .001), a difference not observed for posterior approach patients. CONCLUSION: Anesthesia time is a modifiable risk factor for patient safety and an important factor in healthcare resource utilization. Consideration of ways to reduce DA operative times is encouraged.

Using the Health Belief Model to Examine Adherence to Preventive Measures Among Nursing Students During COVID-19: A Cross-Sectional Analysis.

ABSTRACT: Associations between health belief model constructs and engagement in COVID-19 preventive practices were examined in a population of 234 nursing students. Most (93 percent/68 percent, respectively) reported occasionally/frequently performing 6-feet physical distancing and wearing face masks/covering in public. Among health belief model constructs, perceived benefits were significantly associated with practicing physical distancing; perceived barriers were associated with lower likelihood. Perceived self-efficacy was associated with a greater likelihood of wearing face masks/covering in public. Nursing students should be provided timely and relevant information on preventive measures based on the recognition of different risk appraisals among students.

EVALUATION OF PROGNOSTIC INDICATORS FOR INJURED TURTLES PRESENTING TO A WILDLIFE CLINIC.

The Turtle Rescue Team (TRT) at North Carolina State University College of Veterinary Medicine currently sees over 500 chelonian cases a year. Each turtle receives a thorough physical examination as the main evaluation of its health because further diagnostics are cost prohibitive in a donation-based facility. Thus, there is a need to further understand how a few economical diagnostics can evaluate the prognosis of chelonians. The objectives were to evaluate lactate, PCV, total solids, glucose, temperature, and HR as prognostic indicators in multiple chelonian species and to determine how the change in lactate concentrations over a 24 h period affects prognosis. Eastern box turtles (Terrapene carolina carolina), yellow-bellied sliders (Trachemys scripta scripta), river cooters (Pseudemys concinna), painted turtles (Chrysemys picta), and common snapping turtles (Chelydra serpentina) were evaluated because of prevalence of presentation to the TRT, differences in habitat, and differences in physiology. Hyperlactatemia, an increased lactate over 24 h when the initial lactate concentration was greater than 5 mM/L, and anemia were determined to be significant prognostic indicators of mortality for all turtles, and hypoglycemia was a significant prognostic indicator of mortality for male turtles (P < 0.05).