Serum and Urine Metabolites and Kidney Function.

BACKGROUND: Metabolites represent a read-out of cellular processes underlying states of health and disease. METHODS: We evaluated cross-sectional and longitudinal associations between 1255 serum and 1398 urine known and unknown (denoted with "X" in name) metabolites (Metabolon HD4, 721 detected in both biofluids) and kidney function in 1612 participants of the Atherosclerosis Risk in Communities (ARIC) Study. All analyses were adjusted for clinical and demographic covariates, including for baseline eGFR and UACR in longitudinal analyses. RESULTS: At visit 5 of the ARIC study, the mean age of participants was 76 years (SD 6), 56% were women, mean eGFR was 62 ml/min/1.73m2 (SD 20), and median urine albumin-to-creatinine level (UACR) was 13 mg/g (IQR 25). In cross-sectional analysis, 675 serum and 542 urine metabolites were associated with eGFR (Bonferroni-corrected p < 4.0E-5 for serum analyses and p < 3.6E-5 for urine analyses), including 248 metabolites shared across biofluids. Fewer metabolites (75 serum and 91 urine metabolites, including 7 shared across biofluids) were cross-sectionally associated with albuminuria. Guanidinosuccinate, N2,N2-dimethylguanosine, hydroxy-N6,N6,N6-trimethyllysine, X-13844, and X-25422 were significantly associated with both eGFR and albuminuria. Over a mean follow-up of 6.6 years, serum mannose (HR 2.3 [1.6,3.2], p = 2.7E-5) and urine X-12117 (HR 1.7 [1.3,2.2], p = 1.9E-5) were risk factors for UACR doubling, whereas urine sebacate (HR 0.86 [0.80,0.92], p = 1.9E-5) was inversely associated. Compared to clinical characteristics alone, including the top 5 endogenous metabolites in serum and urine associated with longitudinal outcomes improved the outcome prediction (AUCs for eGFR decline: clinical model = 0.79, clinical + metabolites model = 0.87, p = 8.1E-6; for UACR doubling: clinical model = 0.66, clinical + metabolites model = 0.73, p = 2.9E-5). CONCLUSIONS: Metabolomic profiling in different biofluids provided distinct and potentially complementary insights into the biology and prognosis of kidney diseases.

Lack of effects of online HD-tDCS over the left or right DLPFC in an associative memory and metamemory monitoring task.

Neuroimaging studies have shown that activity in the prefrontal cortex correlates with two critical aspects of normal memory functioning: retrieval of episodic memories and subjective "feelings-of-knowing" about our memory. Brain stimulation can be used to test the causal role of the prefrontal cortex in these processes, and whether the role differs for the left versus right prefrontal cortex. We compared the effects of online High-Definition transcranial Direct Current Stimulation (HD-tDCS) over the left or right dorsolateral prefrontal cortex (DLPFC) compared to sham during a proverb-name associative memory and feeling-of-knowing task. There were no significant effects of HD-tDCS on either associative recognition or feeling-of-knowing performance, with Bayesian analyses showing moderate support for the null hypotheses. Despite past work showing effects of HD-tDCS on other memory and feeling-of-knowing tasks, and neuroimaging showing effects with similar tasks, these findings add to the literature of non-significant effects with tDCS. This work highlights the need to better understand factors that determine the effectiveness of tDCS, especially if tDCS is to have a successful future as a clinical intervention.

Effects of nicotinamide riboside in ovo feeding on high-yield broiler performance, meat quality, and myopathy incidence.

Introduction: The objective of this study was to examine the effects of in ovo nicotinamide riboside (NR) feeding on high-yield broiler growth and meat quality. Methods: Fertilized Cobb 700 by-product eggs (N = 3,240) were randomly assigned to one of four in ovo treatments and injected with 0 (0NR), 250 (250NR), 500 (500NR), or 1,000 (1,000NR) mM NR at incubation-day 10. Chicks were hatched, vent sexed, and randomly placed 18 per pen in one of 32 floor pens. On day 48, birds were processed and deboned. Results: There were dose effects for all part weights (p < 0.05). Pectoralis major weight of 250, 500, and 1,000NR carcasses were heavier than 0NR (p < 0.03) but did not differ from remaining NR doses (p > 0.26). Pectoralis minor weight of 250NR carcasses was greater (p < 0.01) than 0NR and did not differ from other NR tenders (p > 0.21). Pectoralis minor weight of 500 and 1,000NR carcasses was greater than 0NR (p < 0.09), but did not differ (P = 0.82) from each other. There were no dose effects for all Pectoralis major and minor myopathy scores and incidence except incidence of tenders scoring "0" and "1" for woody-like tender. Percentage of NR1,000 tenders scoring 0 and 1 for woody-like tender were less than and greater than all other treatments, respectively (p < 0.05). There were no differences among remaining NR doses and NR0 tenders (p > 0.10). There were dose effects for muscle fiber number (P = 0.03). There tended to be more muscle fibers within 250 and 1,000NR muscles compared to 0NR (p < 0.09). Pectoralis major muscle from 500NR did not differ in muscle fiber number compared to 250 and 1,000NR (p > 0.18), but had more (p < 0.01) fibers than 0NR muscle. There tended to be more fibers in 250 and 1,000NR muscles compared to 0NR muscle (p < 0.09). Discussion: Nicotinamide riboside in ovo feeding caused birds to produce heavier parts; however, myopathy scores and incidence were minimally affected which may have been due greater muscle fiber number.

Urine Biomarkers of Kidney Tubule Health and Risk of Incident CKD in Persons Without Diabetes: The ARIC, MESA, and REGARDS Studies.

Rationale & Objective: Tubulointerstitial damage is a feature of early chronic kidney disease (CKD), but current clinical tests capture it poorly. Urine biomarkers of tubulointerstitial health may identify risk of CKD. Study Design: Prospective cohort (Atherosclerosis Risk in Communities [ARIC]) and case-cohort (Multi-Ethnic Study of Atherosclerosis [MESA] and Reasons for Geographic and Racial Differences in Stroke [REGARDS]). Setting & Participants: Adults with estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 and without diabetes in the ARIC, REGARDS, and MESA studies. Exposures: Baseline urine monocyte chemoattractant protein-1 (MCP-1), alpha-1-microglobulin (α1m), kidney injury molecule-1, epidermal growth factor, and chitinase-3-like protein 1. Outcome: Incident CKD or end-stage kidney disease. Analytical Approach: Multivariable Cox proportional hazards regression for each cohort; meta-analysis of results from all 3 cohorts. Results: 872 ARIC participants (444 cases of incident CKD), 636 MESA participants (158 cases), and 924 REGARDS participants (488 cases) were sampled. Across cohorts, mean age ranged from 60 ± 10 to 63 ± 8 years, and baseline eGFR ranged from 88 ± 13 to 91 ± 14 mL/min/1.73 m2. In ARIC, higher concentrations of urine MCP-1, α1m, and kidney injury molecule-1 were associated with incident CKD. In MESA, higher concentration of urine MCP-1 and lower concentration of epidermal growth factor were each associated with incident CKD. In REGARDS, none of the biomarkers were associated with incident CKD. In meta-analysis of all 3 cohorts, each 2-fold increase α1m concentration was associated with incident CKD (HR, 1.19; 95% CI, 1.08-1.31). Limitations: Observational design susceptible to confounding; competing risks during long follow-up period; meta-analysis limited to 3 cohorts. Conclusions: In 3 combined cohorts of adults without prevalent CKD or diabetes, higher urine α1m concentration was independently associated with incident CKD. 4 biomarkers were associated with incident CKD in at least 1 of the cohorts when analyzed individually. Kidney tubule health markers might inform CKD risk independent of eGFR and albuminuria.

This study analyzed 3 cohorts (ARIC, MESA, and REGARDS) of adults without diabetes or prevalent chronic kidney disease (CKD) to determine the associations of 5 urinary biomarkers of kidney tubulointerstitial health with incident CKD, independent of traditional measures of kidney health. Meta-analysis of results from all 3 cohorts suggested that higher baseline levels of urine alpha-1-microglobulin were associated with incident CKD at follow-up. Results from individual cohorts suggested that in addition to alpha-1-microglobulin, monocyte chemoattractant protein-1, kidney injury molecule-1, and epidermal growth factor may also be associated with the development of CKD. These findings underscore the importance of kidney tubule interstitial health in defining risk of CKD independent of creatinine and urine albumin.

Association of Homelessness with Before Medically Advised Discharge After Surgery.

BACKGROUND: Before medically advised (BMA) discharge, which refers to patients leaving the hospital at their own discretion, is associated with higher rates of readmission and death in other settings. It is not known if housing status is associated with this phenomenon after surgery. METHODS: We identified all admitted adults who underwent an operation by one of 11 different surgical services at a single tertiary care hospital between January 2013 and June 2022. Chi-square tests and t-tests were used to compare demographic and clinical features between BMA discharges and standard discharges. Multivariable logistic regression was used to evaluate the association between housing status and BMA discharge, adjusting for demographic and admission characteristics. Documented reasons for BMA discharge were also abstracted from the medical record. RESULTS: Of 111,036 patient admissions, 242 resulted in BMA discharge (0.2%). After adjusting for observable confounders, patients experiencing homelessness had substantially higher odds of BMA discharge after surgery (adjusted odds ratio 4.4, 95% confidence interval 3.0-6.4; p < 0.001) when compared to housed. Patients who underwent emergency surgery, patients with a documented substance use disorder, and those insured by Medicaid also had significantly higher odds of BMA discharge. System- or provider-related reasons (including patient frustration with the hospital environment, challenges in managing substance dependence, and perceived inadequacy of paint control) were documented in 96% of BMA discharges for patients experiencing homelessness (vs. 66% in housed patients). CONCLUSION: BMA discharge is more common in patients experiencing homelessness after surgery even after adjusting for observable confounding characteristics. Deeper understanding of the drivers of BMA discharge in patients experiencing homelessness through qualitative methods are critical to promote more equitable and effective care.

Offline Two-Dimensional Liquid Chromatography-Mass Spectrometry for Deep Annotation of the Fecal Metabolome Following Fecal Microbiota Transplantation.

Biological interpretation of untargeted LC-MS-based metabolomics data depends on accurate compound identification, but current techniques fall short of identifying most features that can be detected. The human fecal metabolome is complex, variable, incompletely annotated, and serves as an ideal matrix to evaluate novel compound identification methods. We devised an experimental strategy for compound annotation using multidimensional chromatography and semiautomated feature alignment and applied these methods to study the fecal metabolome in the context of fecal microbiota transplantation (FMT) for recurrent C. difficile infection. Pooled fecal samples were fractionated using semipreparative liquid chromatography and analyzed by an orthogonal LC-MS/MS method. The resulting spectra were searched against commercial, public, and local spectral libraries, and annotations were vetted using retention time alignment and prediction. Multidimensional chromatography yielded more than a 2-fold improvement in identified compounds compared to conventional LC-MS/MS and successfully identified several rare and previously unreported compounds, including novel fatty-acid conjugated bile acid species. Using an automated software-based feature alignment strategy, most metabolites identified by the new approach could be matched to features that were detected but not identified in single-dimensional LC-MS/MS data. Overall, our approach represents a powerful strategy to enhance compound identification and biological insight from untargeted metabolomics data.

Heat-activated growth of metastable and length-defined DNA fibers expands traditional polymer assembly.

Biopolymers such as nucleic acids and proteins exhibit dynamic backbone folding, wherein site-specific intramolecular interactions determine overall structure. Proteins then hierarchically assemble into supramolecular polymers such as microtubules, that are robust yet dynamic, constantly growing or shortening to adjust to cellular needs. The combination of dynamic, energy-driven folding and growth with structural stiffness and length control is difficult to achieve in synthetic polymer self-assembly. Here we show that highly charged, monodisperse DNA-oligomers assemble via seeded growth into length-controlled supramolecular fibers during heating; when the temperature is lowered, these metastable fibers slowly disassemble. Furthermore, the specific molecular structures of oligomers that promote fiber formation contradict the typical theory of block copolymer self-assembly. Efficient curling and packing of the oligomers - or 'curlamers' - determine morphology, rather than hydrophobic to hydrophilic ratio. Addition of a small molecule stabilises the DNA fibers, enabling temporal control of polymer lifetime and underscoring their potential use in nucleic-acid delivery, stimuli-responsive biomaterials, and soft robotics.

Latent profile analysis reveals overlapping ARFID and shape/weight motivations for restriction in eating disorders.

BACKGROUND: DSM-5 differentiates avoidant/restrictive food intake disorder (ARFID) from other eating disorders (EDs) by a lack of overvaluation of body weight/shape driving restrictive eating. However, clinical observations and research demonstrate ARFID and shape/weight motivations sometimes co-occur. To inform classification, we: (1) derived profiles underlying restriction motivation and examined their validity and (2) described diagnostic characterizations of individuals in each profile to explore whether findings support current diagnostic schemes. We expected, consistent with DSM-5, that profiles would comprise individuals endorsing solely ARFID or restraint (i.e. trying to eat less to control shape/weight) motivations. METHODS: We applied latent profile analysis to 202 treatment-seeking individuals (ages 10-79 years [M = 26, s.d. = 14], 76% female) with ARFID or a non-ARFID ED, using the Nine-Item ARFID Screen (Picky, Appetite, and Fear subscales) and the Eating Disorder Examination-Questionnaire Restraint subscale as indicators. RESULTS: A 5-profile solution emerged: Restraint/ARFID-Mixed (n = 24; 8% [n = 2] with ARFID diagnosis); ARFID-2 (with Picky/Appetite; n = 56; 82% ARFID); ARFID-3 (with Picky/Appetite/Fear; n = 40; 68% ARFID); Restraint (n = 45; 11% ARFID); and Non-Endorsers (n = 37; 2% ARFID). Two profiles comprised individuals endorsing solely ARFID motivations (ARFID-2, ARFID-3) and one comprising solely restraint motivations (Restraint), consistent with DSM-5. However, Restraint/ARFID-Mixed (92% non-ARFID ED diagnoses, comprising 18% of those with non-ARFID ED diagnoses in the full sample) endorsed ARFID and restraint motivations. CONCLUSIONS: The heterogeneous profiles identified suggest ARFID and restraint motivations for dietary restriction may overlap somewhat and that individuals with non-ARFID EDs can also endorse high ARFID symptoms. Future research should clarify diagnostic boundaries between ARFID and non-ARFID EDs.

Abstinence and Fear Experienced during This Period Produce Distinct Cortical and Hippocampal Adaptations in Alcohol-Dependent Rats.

Previous studies demonstrate that ethanol dependence induced by repeating cycles of chronic intermittent ethanol vapor exposure (CIE) followed by protracted abstinence produces significant gray matter damage via myelin dysfunction in the rodent medial prefrontal cortex (mPFC) and alterations in neuronal excitability in the mPFC and the dentate gyrus (DG) of the hippocampus. Specifically, abstinence-induced neuroadaptations have been associated with persistent elevated relapse to drinking. The current study evaluated the effects of forced abstinence for 1 day (d), 7 d, 21 d, and 42 d following seven weeks of CIE on synaptic plasticity proteins in the mPFC and DG. Immunoblotting revealed reduced expression of CaMKII in the mPFC and enhanced expression of GABAA and CaMKII in the DG at the 21 d time point, and the expression of the ratio of GluN2A/2B subunits did not change at any of the time points studied. Furthermore, cognitive performance via Pavlovian trace fear conditioning (TFC) was evaluated in 3 d abstinent rats, as this time point is associated with negative affect. In addition, the expression of the ratio of GluN2A/2B subunits and a 3D structural analysis of neurons in the mPFC and DG were evaluated in 3 d abstinent rats. Behavioral analysis revealed faster acquisition of fear responses and reduced retrieval of fear memories in CIE rats compared to controls. TFC produced hyperplasticity of pyramidal neurons in the mPFC under control conditions and this effect was not evident or blunted in abstinent rats. Neurons in the DG were unaltered. TFC enhanced the GluN2A/2B ratio in the mPFC and reduced the ratio in the DG and was not altered by abstinence. These findings indicate that forced abstinence from CIE produces distinct and divergent alterations in plasticity proteins in the mPFC and DG. Fear learning-induced changes in structural plasticity and proteins contributing to it were more profound in the mPFC during forced abstinence.

Can Anorectal Stenosis be Managed With Dilations Alone? A PCPLC Review.

PURPOSE: Congenital anorectal stenosis is managed by dilations or operative repair. Recent studies now propose use of dilations as the primary treatment modality to potentially defer or eliminate the need for surgical repair. We aim to characterize the management and outcomes of these patients via a multi-institutional review using the Pediatric Colorectal and Pelvic Learning Consortium (PCPLC) registry. METHODS: A retrospective database review was performed using the PCPLC registry. The patients were evaluated for demographics, co-morbidities, diagnostic work-up, surgical intervention, current bowel management, and complications. RESULTS: 64 patients with anal or rectal stenosis were identified (57 anal, 7 rectal) from a total of 14 hospital centers. 59.6% (anal) and 42.9% (rectal) were male. The median age was 3.2 (anal) and 1.9 years (rectal). 11 patients with anal stenosis also had Currarino Syndrome with 10 of the 11 patients diagnosed with a presacral mass compared to only one rectal stenosis with Currarino Syndrome and a presacral mass. 13 patients (22.8%, anal) and one (14.3%, rectal) underwent surgical correction. Nine patients (8 anal, 1 rectal) underwent PSARP. Other procedures performed were cutback anoplasty and anterior anorectoplasty. The median age at repair was 8.4 months (anal) and 10 days old (rectal). One patient had a wound complication in the anal stenosis group. Bowel management at last visit showed little differences between groups or treatment approach. CONCLUSION: The PCPLC registry demonstrated that these patients can often be managed successfully with dilations alone. PSARP is the most common surgical repair chosen for those who undergo surgical repair. LEVEL OF EVIDENCE: III.

Variation in Practice Surrounding Antegrade Colonic Enema Channel Placement.

PURPOSE: Antegrade colonic enemas (ACE) can be an effective management option for defecation disorders and improve quality of life. Best practice regarding channel placement is unclear and variation may exist around preferred initial type of channel, age at placement, and underlying diagnoses. We aimed to describe practice patterns and patient characteristics around ACE channel placement. METHODS: We conducted a multicenter retrospective study of children with an ACE channel cared for at sites participating in the Pediatric Colorectal and Pelvic Learning Consortium (PCPLC) from 2017 to 2022. Kruskal-Wallis test was utilized to test the age at surgery by site with significance level of 0.05. RESULTS: 500 patients with ACE channel were included. 293 (58.6%) patients had their ACE procedure at a PCPLC center. The median age at surgery was 7.6 [IQR 5.3-11.0] years for the overall cohort and 8.1 [IQR 5.3-11.5] years for placement at PCPLC centers. For PCPLC centers, median age at placement varied significantly across centers (p = 0.009). 371 (74.2%) patients received Malone appendicostomy, 116 (23.2%) received cecostomy, and 13 (2.6%) received Neo-Malone appendicostomy. Median age of patients by channel type was 7.7 [IQR 5.3-11.0], 7.5 [IQR 5.7-11.0], and 9.8 [IQR 4.2-11.6] years, respectively. The most common indication for cecostomy was idiopathic/refractory constipation (52.6%), whereas anorectal malformation was the most common indication for Malone (47.2%) and Neo-Malone (61.5%). Among ACE channels placed at PCPLC centers, there was variation across institutions in preferred initial channel type. The 4 highest volume centers favored Malone appendicostomy over cecostomy. CONCLUSION: There is variation in practice of ACE channel placement. At specialty pediatric colorectal centers, age at time of placement and type of channel placed varied across institutions. Further work is needed to better characterize diagnosis- and age-focused patient centered outcomes to clarify recommendations for our patients who benefit from these procedures. TYPE OF STUDY: Retrospective comparative study. LEVEL OF EVIDENCE: Level III.

Prospective 2-Year Course and Predictors of Outcome in Avoidant/Restrictive Food Intake Disorder.

OBJECTIVE: To evaluate the 2-year course and outcomes of full and subthreshold avoidant/restrictive food intake disorder (ARFID) in youth aged 9 to 23 at baseline using a prospective longitudinal design to characterize the remission and persistence of ARFID, evaluate diagnostic crossover, and identify predictors of outcome. Greater severity in each ARFID profile-sensory sensitivity, fear of aversive consequences, and lack of interest-was hypothesized to predict greater likelihood of illness persistence, controlling for age, sex, body mass index percentile, ARFID treatment status, and baseline diagnosis. METHOD: Participants (N = 100; age range, 9-23 years; 49% female; 91% White) were followed over 2 years. The Pica, ARFID, and Rumination Disorder Interview was used across 3 time points (baseline, year 1, year 2) to measure the severity of each ARFID profile and evaluate illness persistence or remission, and the Eating Disorder Assessment for DSM-5 was used to evaluate diagnostic crossover. RESULTS: Across the 2-year follow-up period, half the participants persisted with their original diagnosis, and 3% of participants experienced a diagnostic shift to anorexia nervosa. Greater severity in the sensory sensitivity and lack of interest profiles was associated with higher likelihood of ARFID persistence at year 1 only; greater severity in the fear of aversive consequences profile was associated with higher likelihood of ARFID remission at year 2 only. CONCLUSION: Findings underscore the distinctiveness of ARFID from other eating disorders and emphasize its persistence over 2 years. Results also highlight the predictive validity and prognostic value of ARFID profiles (ie, sensory sensitivity, fear of aversive consequences, lack of interest).

Chemical Annealing Restructures RNA for Nanopore Detection.

RNA is a key biochemical marker, yet its chemical instability and complex secondary structure hamper its integration into DNA nanotechnology-based sensing platforms. Relying on the denaturation of the native RNA structure using urea, we show that restructured DNA/RNA hybrids can readily be prepared at room temperature. Using solid-state nanopore sensing, we demonstrate that the structures of our DNA/RNA hybrids conform to the design at the single-molecule level. Employing this chemical annealing procedure, we mitigate RNA self-cleavage, enabling the direct detection of restructured RNA molecules for biosensing applications.

Disparities in Mentorship and Implications for US Surgical Resident Education and Wellness.

Importance: Many surgeons cite mentorship as a critical component of training. However, little evidence exists regarding factors associated with mentorship and the influence of mentorship on trainee education or wellness. Objectives: To evaluate factors associated with surgical trainees' perceptions of meaningful mentorship, assess associations of mentorship with resident education and wellness, and evaluate programmatic variation in mentorship. Design, Setting, and Participants: A voluntary, anonymous survey was administered to clinically active residents in all accredited US general surgery residency programs following the 2019 American Board of Surgery In-Service Training Examination. Data were analyzed from July 2019 to July 2022. Exposure: Residents were asked, "Do you have a mentor who genuinely cares about you and your career?" Main Outcomes and Measures: Resident characteristics associated with report of meaningful mentorship were evaluated with multivariable logistic regression. Associations of mentorship with education (clinical and operative autonomy) and wellness (career satisfaction, burnout, thoughts of attrition, suicidality) were examined using cluster-adjusted multivariable logistic regression controlling for resident and program factors. Residents' race and ethnicity were self-identified using US census categories (American Indian or Alaska Native, Asian, Black or African American, Native Hawaiian or Other Pacific Islander, and White), which were combined and dichotomized as non-Hispanic White vs non-White or Hispanic. Results: A total of 6956 residents from 301 programs completed the survey (85.6% response rate); 6373 responded to all relevant questions (2572 [40.3%] female; 2539 [39.8%] non-White or Hispanic). Of these, 4256 (66.8%) reported meaningful mentorship. Non-White or Hispanic residents were less likely than non-Hispanic White residents to report meaningful mentorship (odds ratio [OR], 0.81, 95% CI, 0.71-0.91). Senior residents (postgraduate year 4/5) were more likely to report meaningful mentorship than interns (OR, 3.06; 95% CI, 2.59-3.62). Residents with meaningful mentorship were more likely to endorse operative autonomy (OR, 3.87; 95% CI, 3.35-4.46) and less likely to report burnout (OR, 0.52; 95% CI, 0.46-0.58), thoughts of attrition (OR, 0.42; 95% CI, 0.36-0.50), and suicidality (OR, 0.47; 95% CI, 0.37-0.60) compared with residents without meaningful mentorship. Conclusions and Relevance: One-third of trainees reported lack of meaningful mentorship, particularly non-White or Hispanic trainees. Although education and wellness are multifactorial issues, mentorship was associated with improvement; thus, efforts to facilitate mentorship are needed, especially for minoritized residents.

CXCR2 perturbation promotes Staphylococcus aureus implant-associated infection.

Introduction. Staphylococcus aureus is the leading cause of acute medical implant infections, representing a significant modern medical concern. The success of S. aureus as a pathogen in these cases resides in its arsenal of virulence factors, resistance to multiple antimicrobials, mechanisms of immune modulation, and ability to rapidly form biofilms associated with implant surfaces. S. aureus device-associated, biofilm-mediated infections are often persistent and notoriously difficult to treat, skewing innate immune responses to promote chronic reoccurring infections. While relatively little is known of the role neutrophils play in response to acute S. aureus biofilm infections, these effector cells must be efficiently recruited to sites of infection via directed chemotaxis. Here we investigate the effects of modulating CXC chemokine receptor 2 (CXCR2) activity, predominantly expressed on neutrophils, during S. aureus implant-associated infection.Hypothesis. We hypothesize that modulation of CXCR2 expression and/or signalling activities during S. aureus infection, and thus neutrophil recruitment, extravasation and antimicrobial activity, will affect infection control and bacterial burdens in a mouse model of implant-associated infection.Aim. This investigation aims to elucidate the impact of altered CXCR2 activity during S. aureus biofilm-mediated infection that may help develop a framework for an effective novel strategy to prevent morbidity and mortality associated with implant infections.Methodology. To examine the role of CXCR2 during S. aureus implant infection, we employed a mouse model of indwelling subcutaneous catheter infection using a community-associated methicillin-resistant S. aureus (MRSA) strain. To assess the role of CXCR2 induction or inhibition during infection, treatment groups received daily intraperitoneal doses of either Lipocalin-2 (Lcn2) or AZD5069, respectively. At the end of the study, catheters and surrounding soft tissues were analysed for bacterial burdens and dissemination, and Cxcr2 transcription within the implant-associated tissues was quantified.Results. Mice treated with Lcn2 developed higher bacterial burdens within the soft tissue surrounding the implant site, which was associated with increased Cxcr2 expression. AZD5069 treatment also resulted in increased implant- and tissues-associated bacterial titres, as well as enhanced Cxcr2 expression.Conclusion. Our results demonstrate that CXCR2 plays an essential role in regulating the severity of S. aureus implant-associated infections. Interestingly, however, perturbation of CXCR2 expression or signalling both resulted in enhanced Cxcr2 transcription and elevated implant-associated bacterial burdens. Thus, CXCR2 appears finely tuned to efficiently recruit effector cells and mediate control of S. aureus biofilm-mediated infection.

Divergent Polymer Superstructures from Protonated Poly(adenine) DNA and RNA.

Studies have shown that poly(adenine) DNA and RNA strands protonate at a low pH to form self-associating duplexes; however, the nanoscopic morphology of these structures is unclear. Here, we use Transition Electron Microscopy (TEM), Atomic Force Microscopy (AFM), dynamic light scattering (DLS), and fluorescence spectroscopy to show that both ribose identity (DNA or RNA) and assembly conditions (thermal or room-temperature annealing) dictate unique hierarchical structures for poly(adenine) sequences at a low pH. We show that while the thermodynamic product of protonating poly(adenine) DNA is a discrete dimer of two DNA strands, the kinetic product is a supramolecular polymer that branches and aggregates to form micron-diameter superstructures. In contrast, we find that protonated poly(A) RNA polymerizes into micrometer-length, twisted fibers under the same conditions. These divergent hierarchical morphologies highlight the amplification of subtle chemical differences between RNA and DNA into unique nanoscale behaviors. With the use of poly(adenine) strands spanning vaccine technologies, sensing, and dynamic biotechnology, understanding and controlling the underlying assembly pathways of these structures are critical to developing robust, programmable nanotechnologies.

Multidimensional analysis of cortical interneuron synaptic features reveals underlying synaptic heterogeneity.

Cortical interneurons represent a diverse set of neuronal subtypes characterized in part by their striking degree of synaptic specificity. However, little is known about the extent of synaptic diversity because of the lack of unbiased methods to extract synaptic features among interneuron subtypes. Here, we develop an approach to aggregate image features from fluorescent confocal images of interneuron synapses and their post-synaptic targets, in order to characterize the heterogeneity of synapses at fine scale. We started by training a model that recognizes pre- and post-synaptic compartments and then determines the target of each genetically-identified interneuron synapse in vitro and in vivo. Our model extracts hundreds of spatial and intensity features from each analyzed synapse, constructing a multidimensional data set, consisting of millions of synapses, which allowed us to perform an unsupervised analysis on this dataset, uncovering novel synaptic subgroups. The subgroups were spatially distributed in a highly structured manner that revealed the local underlying topology of the postsynaptic environment. Dendrite-targeting subgroups were clustered onto subdomains of the dendrite along the proximal to distal axis. Soma-targeting subgroups were enriched onto different postsynaptic cell types. We also find that the two main subclasses of interneurons, basket cells and somatostatin interneurons, utilize distinct strategies to enact inhibitory coverage. Thus, our analysis of multidimensional synaptic features establishes a conceptual framework for studying interneuron synaptic diversity.

Disease progression, survival, and molecular disparities in Black and White patients with endometrioid endometrial carcinoma in real-world registries and GOG/NRG oncology randomized phase III clinical trials.

OBJECTIVE: Investigate racial disparities in outcomes and molecular features in Black and White patients with endometrioid endometrial carcinoma (EEC). METHODS: Black and White patients diagnosed with EEC who underwent hysterectomy ± adjuvant treatment in SEER, National Cancer Database (NCDB), the Genomics Evidence Neoplasia Information Exchange (GENIE) project (v.13.0), and eight NCI-sponsored randomized phase III clinical trials (RCTs) were studied. Hazard ratio (HR) and 95% confidence interval (CI) were estimated for cancer-related death (CRD), non-cancer death (NCD), and all-cause death. RESULTS: Black (n = 4397) vs. White (n = 47,959) patients in SEER had a HR (95% CI) of 2.04 (1.87-2.23) for CRD and 1.22 (1.09-1.36) for NCD. In NCDB, the HR (95% CI) for death in Black (n = 13,468) vs. White (n = 155,706) patients was 1.52 (1.46-1.58) dropping to 1.29 (1.23-1.36) after propensity-score matching for age, comorbidity, income, insurance, grade, stage, LVSI, and treatment. In GENIE, Black (n = 109) vs. White (n = 1780) patients had fewer PTEN, PIK3R1, FBXW7, NF1, mTOR, CCND1, and PI3K-pathway-related gene mutations. In contrast, TP53 and DNA-repair-related gene mutation frequency as well as tumor mutational burden-high status were similar in Black and White patients. In RCTs, Black (n = 187) vs. White (n = 2877) patients were more likely to have advanced or recurrent disease, higher grade, worse performance status and progressive disease. Risk of death in Black vs. White patients in RCTs was 2.19 (1.77-2.71) persisting to 1.32 (1.09-1.61) after matching for grade, stage, and treatment arm while balancing age and performance status. CONCLUSIONS: Differences exist in clinical presentation, outcomes, and molecular features in Black vs. White patients with EEC in real-world registries and RCTs. Targeted-drug development, strategies to modify social determinants, and diverse inclusion in RCTs are approaches to reduce disparities.