In vivo dosimetry with an inorganic scintillation detector during multi-channel vaginal cylinder pulsed dose-rate brachytherapy: Dosimetry for pulsed dose-rate brachytherapy.

Background and purpose: In vivo dosimetry is not standard in brachytherapy and some errors go undetected. The aim of this study was to evaluate the accuracy of multi-channel vaginal cylinder pulsed dose-rate brachytherapy using in vivo dosimetry. Materials and methods: In vivo dosimetry data was collected during the years 2019-2022 for 22 patients (32 fractions) receiving multi-channel cylinder pulsed dose-rate brachytherapy. An inorganic scintillation detector was inserted in a cylinder channel. Each fraction was analysed as independent data sets. In vivo dosimetry-based source-tracking was used to determine the relative source-to-detector position. Measured dose was compared to planned and re-calculated source-tracking based doses. Assuming no change in organ and applicator geometry throughout treatment, the planned and source-tracking based dose distributions were compared in select volumes via γ-index analysis and dose-volume-histograms. Results: The mean ± SD planned vs. measured dose deviations in the first pulse were 0.8 ± 5.9 %. In 31/32 fractions the deviation was within the combined in vivo dosimetry uncertainty (averaging 9.7 %, k = 2) and planning dose calculation uncertainty (1.6 %, k = 2). The dwell-position offsets were < 2 mm for 88 % of channels, with the largest being 5.1 mm (4.0 mm uncertainty, k = 2). 3 %/2 mm γ pass-rates averaged 97.0 % (clinical target volume (CTV)), 100.0 % (rectum), 99.9 % (bladder). The mean ± SD deviation was -1. 1  ± 2.9 % for CTV D98, and -0.2 ± 0.9 % and -1.2 ± 2.5 %, for bladder and rectum D2cm3 respectively, indicating good agreement between intended and delivered dose. Conclusions: In vivo dosimetry verified accurate and stable dose delivery in multi-channel vaginal cylinder based pulsed dose-rate brachytherapy.

Pseudomonas aeruginosa modulates both Caenorhabditis elegans attraction and pathogenesis by regulating nitrogen assimilation.

Detecting chemical signals is important for identifying food sources and avoiding harmful agents. Like many animals, C. elegans use olfaction to chemotax towards their main food source, bacteria. However, little is known about the bacterial compounds governing C. elegans attraction to bacteria and the physiological importance of these compounds to bacteria. Here, we address these questions by investigating the function of a small RNA, P11, in the pathogen, Pseudomonas aeruginosa, that was previously shown to mediate learned pathogen avoidance. We discovered that this RNA also affects the attraction of untrained C. elegans to P. aeruginosa and does so by controlling production of ammonia, a volatile odorant produced during nitrogen assimilation. We describe the complex regulation of P. aeruginosa nitrogen assimilation, which is mediated by a partner-switching mechanism involving environmental nitrates, sensor proteins, and P11. In addition to mediating C. elegans attraction, we demonstrate that nitrogen assimilation mutants perturb bacterial fitness and pathogenesis during C. elegans infection by P. aeruginosa. These studies define ammonia as a major mediator of trans-kingdom signaling, implicate nitrogen assimilation as important for both bacteria and host organisms, and highlight how a bacterial metabolic pathway can either benefit or harm a host in different contexts.

Resolving intermediates during the growth of aluminum deuteroxide (Hydroxide) polymorphs in high chemical potential solutions.

Aluminum hydroxide polymorphs are of widespread importance yet their kinetics of nucleation and growth remain beyond the reach of current models. Here we attempt to unveil the reaction processes underlying the polymorphs formation at high chemical potential. We examine their formation in-situ from supersaturated alkaline sodium aluminate solutions using deuteration and time-resolved neutron pair distribution function analyses, which indicate the formation of individual Al(OD)3 layers as an intermediate particle phase. These layers ultimately stack to form gibbsite- or bayerite-like layered heterostructures. Ex-situ characterization of the recovered precipitates using 27Al magic angle spinning nuclear magnetic resonance spectroscopy, Raman, X-ray diffraction, and scanning electron microscopy, suggests the presence of additional intermediate states, an amorphous compound bearing both tetrahededrally- and penta-coordinated Al3+. These observations reveal the complex pathways to form Al(OD)3 monolayers via either transient pentacoordinate species or amorphous-to-ordered transitions. The subsequent crystallization of admixed gibbsite/bayerite is followed by an Al(OD)3 monolayer attachment process.

Local Coordination Environment of Lanthanides Adsorbed onto Cr- and Zr-based Metal-Organic Frameworks.

Separating individual lanthanide (Ln) elements in aqueous mixtures is challenging. Ion-selective capture by porous materials, such as metal-organic frameworks (MOFs), is a promising approach. To design ion-selective MOFs, molecular details of the Ln adsorption complexes within the MOFs must be understood. We determine the local coordination environment of lanthanides Nd(III), Gd(III), and Lu(III) adsorbed onto Cr(III)-based terephthalate MOF (Cr-MIL-101) and Zr(IV)-based Universitet in Oslo MOFs (UiO-66 and UiO-68) and their derivatives. In the Cr(III)- and Zr(IV)-based MOFs, Ln adsorb as inner-sphere complexes at the metal oxo clusters, regardless of whether the organic linkers are decorated with amino groups. Missing linkers result in favorable Ln binding sites at oxo clusters; however, Ln can coordinate to metal sites even with linkers in place. MOF functionalization with phosphonate groups led to Ln chemisorption onto these groups, which out-compete metal cluster sites. Ln form monodentate and bidentate and mononuclear and binuclear surface complexes. We conclude that MOFs for ion-selective Ln capture can be designed by a combination of (1) maximizing metal-lanthanide interactions via shared O atoms at the metal oxo cluster sites, where mixed oxo clusters can lead to ion-selective Ln adsorption, and (2) functionalizing MOFs with Ln-selective groups capable of out-completing the metal oxo cluster sites.

Cell-cell fusion in cancer: The next cancer hallmark?

In this review, we consider the role of cell-cell fusion in cancer development and progression through an evolutionary lens. We begin by summarizing the origins of fusion proteins (fusogens), of which there are many distinct classes that have evolved through convergent evolution. We then use an evolutionary framework to highlight how the persistence of fusion over generations and across different organisms can be attributed to traits that increase fitness secondary to fusion; these traits map well to the expanded hallmarks of cancer. By studying the tumor microenvironment, we can begin to identify the key selective pressures that may favor higher rates of fusion compared to healthy tissues. The paper concludes by discussing the increasing number of research questions surrounding fusion, recommendations for how to answer them, and the need for a greater interest in exploring cell fusion and evolutionary principles in oncology moving forward.

Quality-of-Life Outcomes Following Endoscopic Resection of Sinonasal Inverted Papilloma.

OBJECTIVES: There is growing interest in assessing patient quality of life (QOL) following treatment of sinonasal tumors, including inverted papilloma (IP). We aimed to elucidate the natural history of postoperative QOL outcomes in IP patients treated with surgery. METHODS: Cases of sinonasal IP treated surgically at 4 tertiary academic rhinology centers were retrospectively reviewed. SNOT-22 scores were used to evaluate QOL preoperatively and postoperatively (1, 3, 6, 12 months). Repeated-measures ANOVA assessed for differences in mean scores over time. Linear regression identified factors associated with QOL longitudinally. RESULTS: 373 patients were analyzed. Mean preoperative SNOT-22 score was 20.6 ± 20.4, which decreased to 16.3 ± 18.8 (p = 0.041) and 11.8 ± 15.0 (p < 0.001) at 1 and 3 months postoperatively, respectively. No further changes in SNOT-22 scores occurred beyond 3 months postoperatively (p > 0.05). When analyzed by SNOT-22 subdomains, nasal, sleep, and otologic/facial subdomain scores (all p < 0.05) demonstrated improvement at 12-month follow-up compared with preoperative scores; this was not observed for the emotional subdomain score (p = 0.800). Recurrent cases were associated with higher long-term SNOT-22 scores (ß = 7.08; p = 0.017). Age, sex, degree of dysplasia, prior surgery, primary site, and smoking history did not correlate with symptoms (all p > 0.05). CONCLUSIONS: QOL outcomes related to IP resection are largely driven by nasal, sleep, and otologic/facial subdomains, though patients appear to experience enduring improvement as early as 3 months postoperatively. Recurrent disease is a major driver of negative QOL. LEVEL OF EVIDENCE: 4 Laryngoscope, 2024.

Barriers and facilitators when seeking healthcare for septic children in Ghana: a single-centre qualitative study of patient caregivers and emergency department clinicians.

BACKGROUND/PURPOSE: Sepsis is a leading cause of morbidity, mortality and healthcare utilisation for children worldwide, particularly in resource-limited regions. In Kumasi, Ghana, organ system failure and mortality in children who present to the emergency department (ED) with symptoms of sepsis are often due to late presentation and lack of recognition and implementation of time-critical evidence-based interventions. The purpose of this study was to assess the barriers and facilitators for families in seeking healthcare for their septic children; and to understand the barriers and facilitators for ED providers in Kumasi to recognise and implement sepsis bundle interventions. DESIGN: Single-centre qualitative interviews of 39 caregivers and 35 ED providers in a teaching hospital in Kumasi, Ghana. RESULTS: Thematic analysis of data from caregivers about barriers included: fear of hospital, finances, transportation, delay from referring hospital, cultural/spiritual differences, limited autonomy and concerns with privacy and confidentiality. Negative impacts on family life included financial strain and neglect of other children. ED providers reported barriers included: lack of training, poor work environment and accessibility of equipment. Facilitators from caregivers and providers included some support from the National Health Insurance. Caregivers reported having positive experiences with frontline clinicians, which encouraged them to return to seek health services. IMPLICATIONS: Qualitative structured interviews identified facilitator and critical barrier themes about seeking healthcare, and sepsis identification/management in the paediatric population arriving for care in our centre in Kumasi, Ghana. This study highlights significant deficiencies in healthcare systems that make sepsis management challenging in these settings.

Maxillary Antrostomy Versus Complete Sinus Surgery for Odontogenic Sinusitis With Frontal Sinus Extension.

OBJECTIVES: Endoscopic sinus surgery (ESS) is often necessary when managing odontogenic sinusitis (ODS), but ESS extent for ODS with extramaxillary sinus involvement has been incompletely studied. This study compared outcomes after wide maxillary antrostomy (MA) alone versus complete ESS for ODS with frontal sinus involvement. METHODS: A multicenter prospective cohort study was conducted on patients with uncomplicated ODS (no extrasinus spread) who underwent ESS when computed tomography demonstrated maxillary, anterior ethmoid (AE), and frontal sinus opacification. Multiple preoperative and postoperative variables were recorded, including 22-item sinonasal outcome tests (SNOT-22) and endoscopic findings. Ultimate SNOT-22 and endoscopic resolution, and time to SNOT-22 and endoscopic resolution were compared between patients who underwent MA alone versus "complete" ESS (maxillary, ethmoid, frontal; not sphenoid). RESULTS: Of 70 patients, mean age was 59.2 years, and 55.7% were male. Thirty-five underwent MA alone, and 35 had complete ESS. At first postoperative visits (mean 9.3 days), AE sinus purulence was more likely resolved after complete ESS compared with MA (97.1% vs. 71.4%, p = 0.006). However, time to resolution of AE purulence was comparable by 6 weeks postoperatively (p = 0.158). There were no significant differences in times to foul smell resolution and achieving ≥9 point SNOT-22 reduction (p > 0.05). CONCLUSIONS: For ODS with frontal sinus involvement, MA alone and complete ESS both resulted in rapid and long-term symptomatic resolution. While ultimate resolution of sinus purulence was equivalent between surgery groups, complete ESS did lead to faster resolution of frontoethmoidal purulence in a significant number of cases. LEVEL OF EVIDENCE: 2 Laryngoscope, 2024.

SURGICAL OUTCOMES OF RETINAL DETACHMENT ASSOCIATED WITH PROLIFERATIVE SICKLE CELL RETINOPATHY.

PURPOSE: To evaluate the long-term anatomic and visual outcomes in eyes with sickle cell retinopathy-related retinal detachments (RDs). METHODS: Patients who underwent surgery for sickle cell retinopathy-related RDs at the Wilmer Eye Institute or Wills Eye Hospital between 2008 and 2020 and followed for at least 6 months postoperatively were retrospectively reviewed. The primary outcome was the rate of single-surgery anatomic success and final reattachment. RESULTS: This study included 30 eyes from 28 patients (16 women and 12 men) with tractional RD (n = 13), rhegmatogenous RD (n = 1), and combined tractional RD/rhegmatogenous RD (n = 16). Mean age was 42.1 ± 15.1 years. The mean follow-up duration was 47.8 ± 34.1 months. Twenty-five (83.3%) eyes underwent pars plana vitrectomy and five (16.7%) eyes underwent pars plana vitrectomy with scleral buckling. Single-surgery anatomic success was achieved in 21 (70.0%) eyes at 6 months. Final reattachment was achieved in 28 (93.3%) eyes (22 eyes [73.3%] without tamponade). Recurrence of RDs was significantly associated with male gender (P = 0.041), absence of previous laser (P = 0.032), iatrogenic breaks (P = 0.035), retinectomy (P = 0.034), and silicone oil tamponade (P = 0.024). Overall, the logarithm of the minimum angle of resolution visual acuity improved from 1.53 ± 0.57 (Snellen equivalent, 20/678) to 1.15 ± 1.01 (20/283) at the final visit (P = 0.03); however, eyes with recurrent RD did not achieve significant visual improvement. CONCLUSION: Pars plana vitrectomy to repair sickle cell retinopathy-related RDs was effective in achieving anatomic success and improving vision in most eyes. Single-surgery anatomic success is critical for optimizing visual outcomes.

Differential modulation of polycomb-associated histone marks by cBAF, pBAF, and gBAF complexes.

Chromatin regulators alter the physical properties of chromatin to make it more or less permissive to transcription by modulating another protein's access to a specific DNA sequence through changes in nucleosome occupancy or histone modifications at a particular locus. Mammalian SWI/SNF complexes are a group of ATPase-dependent chromatin remodelers. In mouse embryonic stem cells, there are three primary forms of mSWI/SNF: canonical BAF (cBAF), polybromo-associated BAF (pBAF), and GLTSCR-associated BAF (gBAF). Nkx2-9 is bivalent, meaning nucleosomes at the locus have active and repressive modifications. In this study, we used unique BAF subunits to recruit each of the three complexes to Nkx2-9 using dCas9-mediated inducible recruitment (FIRE-Cas9). We show that recruitment of cBAF complexes leads to a significant loss of the polycomb repressive-2 H3K27me3 histone mark and polycomb repressive-1 and repressive-2 complex proteins, whereas gBAF and pBAF do not. Moreover, nucleosome occupancy alone cannot explain the loss of these marks. Our results demonstrate that cBAF has a unique role in the direct opposition of polycomb-associated histone modifications that gBAF and pBAF do not share.

Understanding the biosynthesis, metabolic regulation, and anti-phytopathogen activity of 3,7-dihydroxytropolone in Pseudomonas spp.

The genus Pseudomonas is a prolific source of specialized metabolites with significant biological activities, including siderophores, antibiotics, and plant hormones. These molecules play pivotal roles in environmental interactions, influencing pathogenicity, inhibiting microorganisms, responding to nutrient limitation and abiotic challenges, and regulating plant growth. These properties mean that pseudomonads are suitable candidates as biological control agents against plant pathogens. Multiple transposon-based screens have identified a Pseudomonas biosynthetic gene cluster (BGC) associated with potent antibacterial and antifungal activities, which produces 7-hydroxytropolone (7-HT). In this study, we show that this BGC also makes 3,7-dihydroxytropolone (3,7-dHT), which has strong antimicrobial activity toward Streptomyces scabies, a potato pathogen. Through metabolomics and reporter assays, we unveil the involvement of cluster-situated genes in generating phenylacetyl-coenzyme A, a key precursor for tropolone biosynthesis via the phenylacetic acid catabolon. The clustering of these phenylacetic acid genes within tropolone BGCs is unusual in other Gram-negative bacteria. Our findings support the interception of phenylacetic acid catabolism via an enoyl-CoA dehydratase encoded in the BGC, as well as highlighting an essential role for a conserved thioesterase in biosynthesis. Biochemical assays were used to show that this thioesterase functions after a dehydrogenation-epoxidation step catalyzed by a flavoprotein. We use this information to identify diverse uncharacterized BGCs that encode proteins with homology to flavoproteins and thioesterases involved in tropolone biosynthesis. This study provides insights into tropolone biosynthesis in Pseudomonas, laying the foundation for further investigations into the ecological role of tropolone production.IMPORTANCEPseudomonas bacteria produce various potent chemicals that influence interactions in nature, such as metal-binding molecules, antibiotics, or plant hormones. This ability to synthesize bioactive molecules means that Pseudomonas bacteria may be useful as biological control agents to protect plants from agricultural pathogens, as well as a source of antibiotic candidates. We have identified a plant-associated Pseudomonas strain that can produce 3,7-dihydroxytropolone, which has broad biological activity and can inhibit the growth of Streptomyces scabies, a bacterium that causes potato scab. Following the identification of this molecule, we used a combination of genetic, chemical, and biochemical experiments to identify key steps in the production of tropolones in Pseudomonas species. Understanding this biosynthetic process led to the discovery of an array of diverse pathways that we predict will produce new tropolone-like molecules. This work should also help us shed light on the natural function of antibiotics in nature.

Nucleotide sugars correlate with leukocyte telomere length as part of a dyskeratosis congenita metabolomic plasma signature.

Not available.

Subtotal Middle Turbinate Resection in Patients with Chronic Rhinosinusitis with Nasal Polyps is Unlikely to Cause Empty Nose Syndrome: A Multi-Institutional Prospective Study.

BACKGROUND: Empty nose syndrome (ENS) is a poorly understood, debilitating condition affecting a minority of patients who underwent nasal airway surgery, most commonly following inferior turbinate surgery. Few publications have demonstrated middle turbinate resection (MTR) causing ENS, but MTR is still considered a potential cause of ENS. The Empty Nose Syndrome 6-item Questionnaire (ENS6Q) is validated for ENS diagnosis, with ENS6Q ≥ 11 considered highly suggestive of ENS. The purpose of this multicenter study was to determine the incidence of patients with ENS6Q ≥ 11 following subtotal MTR during endoscopic sinus surgery (ESS) for chronic rhinosinusitis with nasal polyps (CRSwNP) by comparing preoperative and postoperative ENS6Q scores. METHODS: A multi-institutional prospective cohort study (8 US institutions) was conducted on patients who underwent bilateral subtotal MTR during ESS for CRSwNP. Preoperative and postoperative ENS6Q scores were compared after at least 12 months of postoperative follow-up. RESULTS: Of 110 patients, mean age was 51.6 years and 59.1% were male. Mean follow-up was 14.5 ± 2.5 months (range 12.1-22.3 months). Mean preoperative and postoperative ENS6Q were 7.7 and 2.2, respectively, demonstrating a mean 5.5 point decrease postoperatively (p < 0.0001). At final follow-up, no patient had an ENS6Q ≥ 11. Of note, 20% of patients had preoperative ENS6Q scores ≥11, but all decreased to <11 postoperatively. CONCLUSIONS: Based on prospective multicenter data over 1-2 years postoperatively, subtotal MTR for CRSwNP never led to ENS6Q scores ≥11, and patients experienced significant decreases in ENS6Q postoperatively. Subtotal MTR during ESS for CRSwNP was, therefore, unlikely to cause ENS even with long-term follow-up. LEVEL OF EVIDENCE: 4 Laryngoscope, 2024.

American Shoulder and Elbow Surgeons perspectives on political advocacy.

BACKGROUND: Physician involvement in political advocacy has become increasingly important in recent years. This study aims to explore the types of involvement and barriers to involvement in political advocacy among American Shoulder and Elbow Surgeons (ASES) members, identify issues considered most important by ASES members, and assess demographic factors that might correlate with involvement in political advocacy efforts among ASES members. METHODS: This survey was conducted by the ASES Political Advocacy Committee over a 2-week period in June 2021. The survey collected demographic information including sex, ethnicity, years in practice, practice type, political affiliation, and level of current involvement in political advocacy. Additional questions consisted of thoughts regarding current health care policy issues and the role of the American Academy of Orthopaedic Surgeons/ASES regarding such policy issues. RESULTS: We received 297 responses for a total response rate of 27%. Of those who responded, 24.6% identified as Democrat, 33% identified as Republican, and 42.4% identified as Independent. There was no difference in political affiliation between membership groups. Physician Reimbursement (82%), Medical Liability Reform (50%), and Physician Ownership (50%) were the most important issues identified among respondents. Physician Ownership, Physician Reimbursement and Graduate Medical Education and Student Loan Reform were most important to those in early practice, while Quality and Research was most important to those with greater than 25 years of practice experience. CONCLUSION: There is strong agreement among surgeons regarding the most important political advocacy issues. The efforts of the American Academy of Orthopaedic Surgeons and ASES should focus on these areas. Additionally, the vast majority of respondents felt that advocacy efforts had a positive impact on patients and surgeons.

Testing the evolutionary drivers of malaria parasite rhythms and their consequences for host-parasite interactions.

Undertaking certain activities at the time of day that maximises fitness is assumed to explain the evolution of circadian clocks. Organisms often use daily environmental cues such as light and food availability to set the timing of their clocks. These cues may be the environmental rhythms that ultimately determine fitness, act as proxies for the timing of less tractable ultimate drivers, or are used simply to maintain internal synchrony. While many pathogens/parasites undertake rhythmic activities, both the proximate and ultimate drivers of their rhythms are poorly understood. Explaining the roles of rhythms in infections offers avenues for novel interventions to interfere with parasite fitness and reduce the severity and spread of disease. Here, we perturb several rhythms in the hosts of malaria parasites to investigate why parasites align their rhythmic replication to the host's feeding-fasting rhythm. We manipulated host rhythms governed by light, food or both, and assessed the fitness implications for parasites, and the consequences for hosts, to test which host rhythms represent ultimate drivers of the parasite's rhythm. We found that alignment with the host's light-driven rhythms did not affect parasite fitness metrics. In contrast, aligning with the timing of feeding-fasting rhythms may be beneficial for the parasite, but only when the host possess a functional canonical circadian clock. Because parasites in clock-disrupted hosts align with the host's feeding-fasting rhythms and yet derive no apparent benefit, our results suggest cue(s) from host food act as a proxy rather than being a key selective driver of the parasite's rhythm. Alternatively, parasite rhythmicity may only be beneficial because it promotes synchrony between parasite cells and/or allows parasites to align to the biting rhythms of vectors. Our results also suggest that interventions can disrupt parasite rhythms by targeting the proxies or the selective factors driving them without impacting host health.

Impact of Psychological Factors on Rehabilitation After Anterior Cruciate Ligament Reconstruction: A Systematic Review.

CONTEXT: Anterior cruciate ligament (ACL) tears are a common orthopaedic injury, and the incidence of ACL reconstruction (ACLR) continues to increase. Current clinical practice guidelines (CPGs) recognize the role of psychological factors in rehabilitation, but patient-reported outcome measures (PROs) and psychological readiness are rarely incorporated into rehabilitation. OBJECTIVE: The purpose of this review was to highlight the importance of psychological health after ACL injury, understand the current metrics used to monitor psychological recovery, and outline how psychological recovery can be better incorporated in current CPGs. DATA SOURCES: A systematic review was conducted using the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines (PRISMA); 63 studies were identified with a PubMed search using the term "ACL Injuries/psychology". STUDY SELECTION: Exclusion criteria included lack of consideration of psychological effects or studies validating PROs after ACLR. Studies were reviewed by multiple reviewers, and a total of 38 studies were included after applying exclusion criteria. STUDY DESIGN: Systematic review. LEVEL OF EVIDENCE: Level 3b. DATA EXTRACTION: Two independent reviewers analyzed the included articles to extract sample size, psychological readiness scale or other measures used, and key results. RESULTS: Psychological outcomes, especially kinesiophobia and fear of reinjury, are seen commonly after ACLR. Psychological factors were shown to impede return to sport (RTS), alter measurable knee biomechanics, and potentially increase the risk for re-rupture. Targeted interventions such as kinesiotaping, knee bracing, and imagery training can help improve psychological and functional testing after ACLR. CONCLUSION: ACLR is often complicated by psychological factors. Psychological readiness is a crucial yet often unincorporated part of rehabilitation. Patients with higher levels of kinesiophobia and lower psychological readiness to RTS specifically should be identified to allow for administration of interventions, such as imagery training, knee bracing, or kinesiotaping, that can mitigate the negative effects of psychological outcomes and improve recovery.

Human gut Actinobacteria boost drug absorption by secreting P-glycoprotein ATPase inhibitors.

Drug efflux transporters are a major determinant of drug efficacy and toxicity. A canonical example is P-glycoprotein (P-gp), an efflux transporter that controls the intestinal absorption of diverse compounds. Despite a rich literature on the dietary and pharmaceutical compounds that impact P-gp activity, its sensitivity to gut microbial metabolites remains an open question. Surprisingly, we found that the cardiac drug-metabolizing gut Actinobacterium Eggerthella lenta increases drug absorption in mice. Experiments in cell culture revealed that E. lenta produces a soluble factor that post-translationally inhibits P-gp ATPase efflux activity. P-gp inhibition is conserved in the Eggerthellaceae family but absent in other Actinobacteria. Comparative genomics identified genes associated with P-gp inhibition. Finally, activity-guided biochemical fractionation coupled to metabolomics implicated a group of small polar metabolites with P-gp inhibitory activity. These results highlight the importance of considering the broader relevance of the gut microbiome for drug disposition beyond first-pass metabolism.

Acute microtubule changes linked to DMD pathology are insufficient to impair contractile function or enhance contraction-induced injury in healthy muscle.

Duchenne muscular dystrophy (DMD) is marked by the genetic deficiency of the dystrophin protein in striated muscle whose consequence is a cascade of cellular changes that predispose the susceptibility to contraction injury central to DMD pathology. Recent evidence identified the proliferation of microtubules enriched in post-translationally modified tubulin as a consequence of dystrophins absence that increases the passive mechanics of the muscle fiber and the excess mechanotransduction elicited reactive oxygen species and calcium signals that promote contraction injury. Motivated by evidence that acutely normalizing the disease microtubule alterations reduced contraction injury in murine DMD muscle (mdx), here we sought the direct impact of these microtubule alterations independent of dystrophins absence and the multitude of other changes consequent to dystrophic disease. To this end we used acute pharmacologic (epithiolone-D, EpoD; 4 hours) or genetic (vashohibin-2 and small vasohibin binding protein overexpression via AAV9; 2 weeks) strategies to effectively model the proliferation of detyrosination enriched microtubules in the mdx muscle. Quantifying in vivo nerve evoked plantarflexor function we find no alteration in peak torque nor contraction kinetics in WT mice modeling these DMD relevant MT alterations. Quantifying the susceptibility to eccentric contraction injury we show EpoD treatment proffered a small but significant protection from contraction injury while VASH/SVBP had no discernable impact. We conclude that the disease dependent MT alterations act in concert with additional cellular changes to predispose contraction injury in DMD.

Spread-out Bragg peak FLASH: quantifying normal tissue toxicity in a murine model.

Objective: A favorable effect of ultra-high dose rate (FLASH) radiation on normal tissue-sparing has been indicated in several preclinical studies. In these studies, the adverse effects of radiation damage were reduced without compromising tumor control. Most studies of proton FLASH investigate these effects within the entrance of a proton beam. However, the real advantage of proton therapy lies in the Spread-out Bragg Peak (SOBP), which allows for giving a high dose to a target with a limited dose to healthy tissue at the entrance of the beam. Therefore, a clinically relevant investigation of the FLASH effect would be of healthy tissues within a SOBP. Our study quantified the tissue-sparing effect of FLASH radiation on acute and late toxicity within an SOBP in a murine model. Material/Methods: Radiation-induced damage was assessed for acute and late toxicity in the same mice following irradiation with FLASH (Field dose rate of 60 Gy/s) or conventional (CONV, 0.34 Gy/s) dose rates. The right hindleg of unanesthetized female CDF1 mice was irradiated with single-fraction doses between 19.9-49.7 Gy for CONV and 30.4-65.9 Gy for FLASH with 5-8 mice per dose. The leg was placed in the middle of a 5 cm SOBP generated from a mono-energetic beam using a 2D range modulator. Acute skin toxicity quantified by hair loss, moist desquamation and toe separation was monitored daily within 29 days post-treatment. Late toxicity of fibrotic development measured by leg extendibility was monitored biweekly until 30 weeks post-treatment. Results: Comparison of acute skin toxicity following radiation indicated a tissue-sparing effect of FLASH compared to conventional single-fraction radiation with a mean protection ratio of 1.40 (1.35-1.46). Fibrotic development similarly indicated normal tissue sparing with a 1.18 (1.17-1.18) protection ratio. The acute skin toxicity tissue sparing was similar to data from entrance-beam irradiations of Sørensen et al. (4). Conclusion: Full dose-response curves for acute and late toxicity after CONV and FLASH radiation were obtained. Radiation within the SOBP retains the normal-tissue-sparing effect of FLASH with a dose-modifying factor of 40% for acute skin damage and 18% for fibrotic development.

Routine Emergency Department Screening to Decrease Subsequent Physical Abuse.

STUDY OBJECTIVE: Emergency department (ED) screening for child physical abuse has been widely implemented, with uncertain effects on child abuse identification. Our goal was to determine the effect of screening on referrals to child protective services (CPS) identifying abuse. METHODS: We performed a retrospective cohort study of children younger than 6 years old with an ED encounter at 1 of 2 large health care systems, one of which implemented routine child abuse screening. The main outcome was initial (<2 days) or subsequent (3 to 180 days) referral to CPS identifying child abuse using linked records. We compared outcomes for the 2-year period after screening was implemented to the preperiod and nonscreening EDs using generalized estimating equations to adjust for sex, age, race/ethnicity, payor and prior ED encounters and clustered by center. RESULTS: Of the 331,120 ED encounters, 41,589 (12.6%) occurred at screening EDs during the screening period. Screening was completed in 34,272 (82%) and was positive in 188 (0.45%). Overall, 7,623 encounters (2.3%) had a subsequent referral, of which 589 (0.2%) identified moderate or severe abuse. ED screening did not change initial (adjusted odds ratio [aOR]=1.01, 95% confidence interval [CI] 0.89 to 1.15) or subsequent referral to CPS when compared to the prescreening period (aOR=1.05, 95% CI 0.9 to 1.18) or to the nonscreening EDs (aOR=1.06, 95% CI 0.92 to 1.21). CONCLUSION: Routine screening did not affect initial or subsequent referrals to CPS.