Macromolecular interactions and geometrical confinement determine the 3D diffusion of ribosome-sized particles in live Escherichia coli cells.

The crowded bacterial cytoplasm is comprised of biomolecules that span several orders of magnitude in size and electrical charge. This complexity has been proposed as the source of the rich spatial organization and apparent anomalous diffusion of intracellular components, although this has not been tested directly. Here, we use biplane microscopy to track the 3D motion of self-assembled bacterial Genetically Encoded Multimeric nanoparticles (bGEMs) with tunable size (20 to 50 nm) and charge (-2160 to +1800 e) in live Escherichia coli cells. To probe intermolecular details at spatial and temporal resolutions beyond experimental limits, we also developed a colloidal whole-cell model that explicitly represents the size and charge of cytoplasmic macromolecules and the porous structure of the bacterial nucleoid. Combining these techniques, we show that bGEMs spatially segregate by size, with small 20-nm particles enriched inside the nucleoid, and larger and/or positively charged particles excluded from this region. Localization is driven by entropic and electrostatic forces arising from cytoplasmic polydispersity, nucleoid structure, geometrical confinement, and interactions with other biomolecules including ribosomes and DNA. We observe that at the timescales of traditional single molecule tracking experiments, motion appears sub-diffusive for all particle sizes and charges. However, using computer simulations with higher temporal resolution, we find that the apparent anomalous exponents are governed by the region of the cell in which bGEMs are located. Molecular motion does not display anomalous diffusion on short time scales and the apparent sub-diffusion arises from geometrical confinement within the nucleoid and by the cell boundary.

A folate inhibitor exploits metabolic differences in Pseudomonas aeruginosa for narrow-spectrum targeting.

Pseudomonas aeruginosa is a leading cause of hospital-acquired infections for which the development of antibiotics is urgently needed. Unlike most enteric bacteria, P. aeruginosa lacks enzymes required to scavenge exogenous thymine. An appealing strategy to selectively target P. aeruginosa is to disrupt thymidine synthesis while providing exogenous thymine. However, known antibiotics that perturb thymidine synthesis are largely inactive against P. aeruginosa.Here we characterize fluorofolin, a dihydrofolate reductase (DHFR) inhibitor derived from Irresistin-16, that exhibits significant activity against P. aeruginosa in culture and in a mouse thigh infection model. Fluorofolin is active against a wide range of clinical P. aeruginosa isolates resistant to known antibiotics. Metabolomics and in vitro assays using purified folA confirm that fluorofolin inhibits P. aeruginosa DHFR. Importantly, in the presence of thymine supplementation, fluorofolin activity is selective for P. aeruginosa. Resistance to fluorofolin can emerge through overexpression of the efflux pumps MexCD-OprJ and MexEF-OprN, but these mutants also decrease pathogenesis. Our findings demonstrate how understanding species-specific genetic differences can enable selective targeting of important pathogens while revealing trade-offs between resistance and pathogenesis.

Wearable technology in the sports medicine clinic to guide the return-to-play and performance protocols of athletes following a COVID-19 diagnosis.

The coronavirus disease 2019 (COVID-19) pandemic has enabled the adoption of digital health platforms for self-monitoring and diagnosis. Notably, the pandemic has had profound effects on athletes and their ability to train and compete. Sporting organizations worldwide have reported a significant increase in injuries manifesting from changes in training regimens and match schedules resulting from extended quarantines. While current literature focuses on the use of wearable technology to monitor athlete workloads to guide training, there is a lack of literature suggesting how such technology can mediate the return to sport processes of athletes infected with COVID-19. This paper bridges this gap by providing recommendations to guide team physicians and athletic trainers on the utility of wearable technology for improving the well-being of athletes who may be asymptomatic, symptomatic, or tested negative but have had to quarantine due to a close exposure. We start by describing the physiologic changes that occur in athletes infected with COVID-19 with extended deconditioning from a musculoskeletal, psychological, cardiopulmonary, and thermoregulatory standpoint and review the evidence on how these athletes may safely return to play. We highlight opportunities for wearable technology to aid in the return-to-play process by offering a list of key parameters pertinent to the athlete affected by COVID-19. This paper provides the athletic community with a greater understanding of how wearable technology can be implemented in the rehabilitation process of these athletes and spurs opportunities for further innovations in wearables, digital health, and sports medicine to reduce injury burden in athletes of all ages.

A Dual-Mechanism Antibiotic Kills Gram-Negative Bacteria and Avoids Drug Resistance.

The rise of antibiotic resistance and declining discovery of new antibiotics has created a global health crisis. Of particular concern, no new antibiotic classes have been approved for treating Gram-negative pathogens in decades. Here, we characterize a compound, SCH-79797, that kills both Gram-negative and Gram-positive bacteria through a unique dual-targeting mechanism of action (MoA) with undetectably low resistance frequencies. To characterize its MoA, we combined quantitative imaging, proteomic, genetic, metabolomic, and cell-based assays. This pipeline demonstrates that SCH-79797 has two independent cellular targets, folate metabolism and bacterial membrane integrity, and outperforms combination treatments in killing methicillin-resistant Staphylococcus aureus (MRSA) persisters. Building on the molecular core of SCH-79797, we developed a derivative, Irresistin-16, with increased potency and showed its efficacy against Neisseria gonorrhoeae in a mouse vaginal infection model. This promising antibiotic lead suggests that combining multiple MoAs onto a single chemical scaffold may be an underappreciated approach to targeting challenging bacterial pathogens.

Conjunctival Melanocytic Nevi With Granular Cell Change.

CONTEXT.­: Granular cell change in melanocytic nevus is underrepresented in the literature with only 4 well-documented cases, 1 described in the conjunctiva. Unfamiliarity with the clinical and pathologic features of these lesions contributes to the diagnostic difficulty. OBJECTIVE.­: To delineate the clinical and histopathologic features of conjunctival nevi with granular cell change. DESIGN.­: In a retrospective observational case series, the medical records of all patients with conjunctival nevi and granular cell change diagnosed between December 2016 and October 2018 were reviewed. Data collected included age, sex, clinical presentation, pathologic findings, and follow-up. RESULTS.­: Twelve patients, 6 males and 6 females, with a median age of 14 years (range, 8-82 years) were identified. The nevus manifested as a pigmented, well-circumscribed nodule (7 of 9; 78%) or patch (2 of 9; 22%) in the bulbar and limbal conjunctiva (7 of 9; 78%) or in the plica semilunaris/caruncle (2 of 9; 22%). Cysts were noted in 7 of 9 lesions (78%). Features prompting surgical excision included atypical pigmentation (8 of 9; 89%), growth (7 of 9; 78%), and atypical vascularity (4 of 9; 44%). Microscopically, all lesions comprised a conventional melanocytic nevus with focal granular cell change and immunoreactivity for Melan-A, SOX10, and HMB-45, with Ki-67 proliferative index of less than 2%. Of the 9 lesions with follow-up information, there were no recurrences over mean follow-up of 11.2 months (range, 1-23 months). CONCLUSIONS.­: Granular cell change in melanocytic nevi is an underrecognized finding that can simulate melanoma clinically and histopathologically. Young age at diagnosis, lack of associated conjunctival melanosis, bulbar location, cysts, and the absence of mitotic figures with a low Ki-67 proliferative index are helpful clinical and pathologic diagnostic clues.

Scaphoid Fracture Repair Does Not Significantly Diminish Short-Term Participation in the National Football League.

BACKGROUND: Fixation of scaphoid fractures is recommended in elite athletes to hasten healing and return-to-sport times. Complications such as nonunion negatively affect athletic performance. QUESTIONS/PURPOSES: The purpose of this study was to examine the prevalence and impact of scaphoid repair on National Football League (NFL) participation during athletes' first season in the NFL, while identifying significant predictors for development of carpal arthritis and scaphoid nonunion. METHODS: A total of 1311 football athletes invited to the NFL Scouting Combine from 2012 to 2015 were evaluated for history of scaphoid fracture repair. Athlete demographics, surgical history, and imaging and physical examination findings were recorded. Future NFL participation based on draft status, games played, and games started during athletes' first season were gathered using publicly available databases. RESULTS: Nineteen (1.4%) athletes underwent 24 operations for scaphoid repair. Limitations in wrist range of motion or strength were present in 47.4% of athletes with a history of repair. Arthritic changes were present in 32% of wrists, while radiographic nonunion was present in two athletes following scaphoid fracture. Defensive backs were observed to have a higher incidence for arthritic changes following repair compared to other positions. No significant difference in prospective NFL participation was found in athletes with a history of scaphoid repair than in those without. CONCLUSIONS: Athletes with a history of scaphoid repair are not at significant risk for diminished participation during their first season in the NFL.

School-Based versus Community-Based Sampling for Trachoma Surveillance.

Trachoma surveillance is typically performed via random sampling of endemic districts. This strategy minimizes bias and allows examination of preschool children, but is also expensive. Surveillance for some other neglected tropical diseases is carried out in schools, which is logistically easier. In the present study, the prevalence of trachomatous inflammation-follicular (TF) from a population-based sample of children from each of 70 communities in Ethiopia was compared with the corresponding school-based estimate, which was calculated for each community by performing examinations in all primary schools in the district. The overall prevalence of TF was 39.1% (95% confidence interval [CI]: 35.0-43.1%) among children aged 1-9 years in the community-based sample and 18.8% (95% CI: 15.9-21.7%) among children in grades 1-3 of the school-based sample. School-based estimates of TF explained 35% of the variation in the community-based prevalences (P < 0.001). When TF prevalence was used as a diagnostic test for detecting a community with > 5% prevalence of ocular chlamydia, the area under the receiver operating characteristic curve was 0.73 (95% CI: 0.60-0.85) for the school-based sample and 0.71 (0.58-0.83) for the community-based sample (P = 0.76). Thus, although school-based monitoring was necessarily biased relative to population-based monitoring of 1- to 9-year olds, the two methods provided a similar amount of information about the community burden of ocular chlamydia in this trachoma-hyperendemic setting. The generalizability of these findings to areas with less prevalent trachoma is unclear.

Conservative Management for Stable High Ankle Injuries in Professional Football Players.

CONTEXT: High ankle "syndesmosis" injuries are common in American football players relative to the general population. At the professional level, syndesmotic sprains represent a challenging and unique injury lacking a standardized rehabilitation protocol during conservative management. EVIDENCE ACQUISITION: PubMed, Biosis Preview, SPORTDiscus, PEDro, and EMBASE databases were searched using the terms syndesmotic injuries, American football, conservative management, and rehabilitation. STUDY DESIGN: Clinical review. LEVEL OF EVIDENCE: Level 3. RESULTS: When compared with lateral ankle sprains, syndesmosis injuries result in significantly prolonged recovery times and games lost. For stable syndesmotic injuries, conservative management features a brief period of immobilization and protected weightbearing followed by progressive strengthening exercises and running, and athletes can expect to return to competition in 2 to 6 weeks. Further research investigating the efficacy of dry needling and blood flow restriction therapy is necessary to evaluate the benefit of these techniques in the rehabilitation process. CONCLUSION: Successful conservative management of stable syndesmotic injuries in professional American football athletes requires a thorough understanding of the anatomy, injury mechanisms, diagnosis, and rehabilitation strategies utilized in elite athletes.

Recurrent Labral Tearing on Magnetic Resonance Imaging Is Not Predictive of Diminished Participation Among National Football League Athletes.

PURPOSE: To investigate the prevalence of shoulder labral repair and utility of magnetic resonance imaging (MRI) in determining the risks of recurrent labral tearing and impact on future participation in the National Football League (NFL). METHODS: Athletes invited to the NFL Combine between 2012 and 2015 were retrospectively reviewed. Athletes with a history of labral repair and MRI of the operative shoulder at the Combine were included in the study for further analysis, excluding athletes without a history of labral repair, labral repair without MRI at the Combine, additional procedure to the operative shoulder, or athletes still undergoing rehabilitation at the time of the Combine after labral repair. All MRIs were reviewed to determine initial labral repair location, the presence of recurrent tearing, and any concomitant shoulder pathology. Prospective information on future NFL participation in regard to draft status, games played, and games started in the athlete's first NFL season after the Combine was compared between athletes with a history of labral repair with and without recurrent tearing versus all other athletes participating in the Combine. RESULTS: A total of 132 (10.1%) athletes underwent 146 shoulder labral repair procedures before the NFL Combine, of whom 32% (n = 39 athletes, n = 46 shoulders) had recurrent labral tears on MRI. Athletes with recurrent tears were more likely to have undergone bilateral labral repairs (P = .048) and possess concomitant shoulder pathology (P < .001). Recurrent labral tearing was significantly more common in the posterior labrum in athletes with a history of posterior labral repairs (P = .032). Prospective participation in the NFL in terms of games played (P = .38) or started (P = .98) was not significantly reduced in athletes with a history of labral repair compared with those without repair. Participation was not diminished in athletes with recurrent labral tears compared with those with intact repairs or those with evidence of degenerative joint disease. CONCLUSIONS: Athletes invited to the NFL Scouting Combine with a history of bilateral repair, posterior labral repair, and concomitant shoulder pathology are at high risk of recurrent labral tearing on MRI. No significant reduction in NFL participation the year after the Combine was seen in athletes with a history of labral repair, recurrent labral tearing, or degenerative joint disease who were successfully drafted into the NFL. In athletes with a history of labral repair, assessment of labral integrity on MRI alone is not predictive of future short-term participation. LEVEL OF EVIDENCE: Level IV, prognostic study-case series.

Prevalence of Jones Fracture Repair and Impact on Short-Term NFL Participation.

BACKGROUND: Elite American football athletes are at high risk for Jones fractures. Fixation is recommended to minimize nonunion and allow early return to play. The purpose of this investigation was to evaluate the prevalence of Jones fracture repair in athletes invited to the National Football League (NFL) Combine and the impact of fracture repair on short-term NFL participation compared to athletes with no history of repair. METHODS: A total of 1311 athletes participating in the Combine from 2012 to 2015 were evaluated. Athletes with history of Jones fracture repair were identified. Athlete demographic information was collected while physical examination findings were recorded. Radiographs were evaluated to determine fixation type and the presence of nonunion. Future participation in the NFL was evaluated based on draft status, games played, and games started in the athlete's first season following the Combine. RESULTS: Fixation was performed for 41 Jones fractures in 40 athletes (3.1%). The highest prevalence was in defensive linemen (n = 10 athletes), with the greatest rate in tight ends (5.1%, n = 4 of 79 athletes). Intramedullary screw fixation was used for all fractures. Incomplete bony union was present in 3 (8%) fractures. Athletes with a history of repair were not at significant risk for going undrafted ( P = .61), playing ( P = .23), or starting ( P = .76) fewer NFL games compared to athletes with no history of repair during athletes' first NFL season. CONCLUSION: Athletes with a history of Jones fracture repair were not at significant risk of going undrafted or for diminished participation during their first season in the NFL. LEVEL OF EVIDENCE: Level IV, case series.

Synthesis of Thermogelling Poly(N-isopropylacrylamide)-graft-chondroitin Sulfate Composites with Alginate Microparticles for Tissue Engineering.

Injectable biomaterials are defined as implantable materials that can be introduced into the body as a liquid and solidify in situ. Such materials offer the clinical advantages of being implanted minimally invasively and easily forming space-filling solids in irregularly shaped defects. Injectable biomaterials have been widely investigated as scaffolds for tissue engineering. However, for the repair of certain load-bearing areas in the body, such as the intervertebral disc, scaffolds should possess adhesive properties. This will minimize the risk of dislocation during motion and ensure intimate contact with the surrounding tissue, providing adequate transmission of forces. Here, we describe the preparation and characterization of a scaffold composed of thermally sensitive poly(N-isopropylacrylamide)-graft-chondroitin sulfate (PNIPAAM-g-CS) and alginate microparticles. The PNIPAAm-g-CS copolymer forms a viscous solution in water at RT, into which alginate particles are suspended to enhance adhesion. Above the lower critical solution temperature (LCST), around 30 °C, the copolymer forms a solid gel around the microparticles. We have adapted standard biomaterials characterization procedures to take into account the reversible phase transition of PNIPAAm-g-CS. Results indicate that the incorporation of 50 or 75 mg/ml alginate particles into 5% (w/v) PNIPAAm-g-CS solutions quadruple the adhesive tensile strength of PNIPAAm-gCS alone (p<0.05). The incorporation of alginate microparticles also significantly increases swelling capacity of PNIPAAm-g-CS (p<0.05), helping to maintain a space-filling gel within tissue defects. Finally, results of the in vitro toxicology assay kit, 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) and Live/Dead viability assay indicate that the adhesive is capable of supporting the survival and proliferation of encapsulated Human Embryonic Kidney (HEK) 293 cells over 5 days.

Wearable Performance Devices in Sports Medicine.

CONTEXT: Wearable performance devices and sensors are becoming more readily available to the general population and athletic teams. Advances in technology have allowed individual endurance athletes, sports teams, and physicians to monitor functional movements, workloads, and biometric markers to maximize performance and minimize injury. Movement sensors include pedometers, accelerometers/gyroscopes, and global positioning satellite (GPS) devices. Physiologic sensors include heart rate monitors, sleep monitors, temperature sensors, and integrated sensors. The purpose of this review is to familiarize health care professionals and team physicians with the various available types of wearable sensors, discuss their current utilization, and present future applications in sports medicine. EVIDENCE ACQUISITION: Data were obtained from peer-reviewed literature through a search of the PubMed database. Included studies searched development, outcomes, and validation of wearable performance devices such as GPS, accelerometers, and physiologic monitors in sports. STUDY DESIGN: Clinical review. LEVEL OF EVIDENCE: Level 4. RESULTS: Wearable sensors provide a method of monitoring real-time physiologic and movement parameters during training and competitive sports. These parameters can be used to detect position-specific patterns in movement, design more efficient sports-specific training programs for performance optimization, and screen for potential causes of injury. More recent advances in movement sensors have improved accuracy in detecting high-acceleration movements during competitive sports. CONCLUSION: Wearable devices are valuable instruments for the improvement of sports performance. Evidence for use of these devices in professional sports is still limited. Future developments are needed to establish training protocols using data from wearable devices.

Reliability of trachoma clinical grading--assessing grading of marginal cases.

BACKGROUND: Clinical examination of trachoma is used to justify intervention in trachoma-endemic regions. Currently, field graders are certified by determining their concordance with experienced graders using the kappa statistic. Unfortunately, trachoma grading can be highly variable and there are cases where even expert graders disagree (borderline/marginal cases). Prior work has shown that inclusion of borderline cases tends to reduce apparent agreement, as measured by kappa. Here, we confirm those results and assess performance of trainees on these borderline cases by calculating their reliability error, a measure derived from the decomposition of the Brier score. METHODS AND FINDINGS: We trained 18 field graders using 200 conjunctival photographs from a community-randomized trial in Niger and assessed inter-grader agreement using kappa as well as reliability error. Three experienced graders scored each case for the presence or absence of trachomatous inflammation-follicular (TF) and trachomatous inflammation-intense (TI). A consensus grade for each case was defined as the one given by a majority of experienced graders. We classified cases into a unanimous subset if all 3 experienced graders gave the same grade. For both TF and TI grades, the mean kappa for trainees was higher on the unanimous subset; inclusion of borderline cases reduced apparent agreement by 15.7% for TF and 12.4% for TI. When we assessed the breakdown of the reliability error, we found that our trainees tended to over-call TF grades and under-call TI grades, especially in borderline cases. CONCLUSIONS: The kappa statistic is widely used for certifying trachoma field graders. Exclusion of borderline cases, which even experienced graders disagree on, increases apparent agreement with the kappa statistic. Graders may agree less when exposed to the full spectrum of disease. Reliability error allows for the assessment of these borderline cases and can be used to refine an individual trainee's grading.

Characterization of injectable hydrogels based on poly(N-isopropylacrylamide)-g-chondroitin sulfate with adhesive properties for nucleus pulposus tissue engineering.

The goal of this work is to develop an injectable nucleus pulposus (NP) tissue engineering scaffold with the ability to form an adhesive interface with surrounding disc tissue. A family of in situ forming hydrogels based on poly(N-isopropylacrylamide)-graft-chondroitin sulfate (PNIPAAm-g-CS) were evaluated for their mechanical properties, bioadhesive strength, and cytocompatibility. It was shown experimentally and computationally with the Neo-hookean hyperelastic model that increasing the crosslink density and decreasing the CS concentration increased mechanical properties at 37 °C, generating several hydrogel formulations with unconfined compressive modulus values similar to what has been reported for the native NP. The adhesive tensile strength of PNIPAAm increased significantly with CS incorporation (p < 0.05), ranging from 0.4 to 1 kPa. Live/Dead and XTT assay results indicate that the copolymer is not cytotoxic to human embryonic kidney (HEK) 293 cells. Taken together, these data indicate the potential of PNIPAAm-g-CS to function as a scaffold for NP regeneration.

Improving pediatric asthma control among minority children participating in medicaid: providing practice redesign support to deliver a chronic care model.

BACKGROUND: Asthma, a leading chronic disease of children, currently affects about 6.2 million (8.5%) children in the United States. Despite advances in asthma research and availability of increasingly effective therapy, many children do not receive appropriate medications to control the disease, have over-reliance on reliever medication, and lack systematic follow-up care. The situation is even worse for poor inner-city and minority children who have significantly worse asthma rates, severity, and outcomes. National Asthma Education and Prevention Program Guidelines recommend a multimodal, chronic care approach. OBJECTIVE: The authors assessed the effectiveness of practice redesign and computerized provider feedback in improving both practitioner adherence to National Asthma Education and Prevention Program Guidelines (NAEPP), and patient outcomes in 295 poor minority children across four Federally Qualified Health Centers (FQHC). METHODS: In a nonrandomized, two-group (intervention versus comparison), two-phase trial, all sites were provided redesign support to provide quarterly well-asthma visits using structured visit forms, community health workers for outreach and follow-up, a Web-based disease registry for tracking and scheduling, and a provider education package. Intervention sites were given an additional Web-based, computerized patient-specific provider feedback system that produced a guideline-driven medication assessment prompt. RESULTS: Logistic regression results showed that providers at intervention sites were more than twice as likely on average to prescribe guideline-appropriate medications after exposure to our feedback system during the Phase I enrollment period than providers at comparison sites (exp(B) = 2.351, confidence interval [CI] = 1.315-4.204). In Phase II (the post-enrollment visit period), hierarchical linear models (HLMs) and latent growth curves were used to show that asthma control improved significantly by .19 (SE = .05) on average for each of the remaining four visits (about 11% of a standard deviation), and improved even more for patients at intervention sites. These results show that implementation of practice redesign support guided by a pediatric chronic care model can improve provider adherence to treatment guidelines as well as patients' asthma control. CONCLUSIONS: The addition of patient-specific feedback for providers results in quicker adoption of guideline recommendations and potentially greater improvements in asthma control compared to the basic practice redesign support alone.

Macular pigment optical density at four retinal loci during 120 days of lutein supplementation.

BACKGROUND: Increased consumption of lutein and zeaxanthin has been shown to increase macular pigment optical density (MPOD) in some individuals. Most interventions either obtained infrequent measures of MPOD or measured MPOD at a single retinal locus. PURPOSE: The aim of this study was to measure acute changes in MPOD at four retinal loci during lutein intervention. METHODS: For 120 days, three subjects consumed 30 mg of lutein and 2.7 mg of zeaxanthin supplement per day. MPOD was measured with heterochromatic flicker photometry at 20', 30', 60' and 120' eccentricity three or four times per week. High-performance liquid chromatography was used to measure serum carotenoid concentrations in blood samples collected at baseline and at 30-day intervals. RESULTS: At the two most central loci, MPOD significantly increased in all three subjects with a mean change of approximately 0.09 log units at 20' eccentricity and 0.08 log units at 30' eccentricity. MPOD significantly increased in two subjects at 60' eccentricity, and in one subject at 120' eccentricity. The increases in MPOD appeared to be linear and continued after treatment was ended. In all three subjects, log sensitivity at the reference locus decreased linearly. Serum lutein and serum zeaxanthin increased from baseline, reaching peak concentrations after 30 days of supplementation. CONCLUSION: The changes in MPOD suggest that carotenoid deposition occurs linearly and may be biased towards the central retina. Further, carotenoid deposition may occur outside the central fovea in interventions with pharmacological doses of carotenoid, resulting in underestimations of psychophysical measures of MPOD.