STEERING FROM THE REAR: COORDINATION OF CENTRAL PATTERN GENERATORS UNDERLYING NAVIGATION BY ASCENDING INTERNEURONS.

Understanding how animals coordinate movements to achieve goals is a fundamental pursuit in neuroscience. Here we explore how neurons that reside in posterior lower-order regions of a locomotor system project to anterior higher-order regions to influence steering and navigation. We characterized the anatomy and functional role of a population of ascending interneurons in the ventral nerve cord of Drosophila larvae. Through electron microscopy reconstructions and light microscopy, we determined that the cholinergic 19f cells receive input primarily from premotor interneurons and synapse upon a diverse array of postsynaptic targets within the anterior segments including other 19f cells. Calcium imaging of 19f activity in isolated central nervous system (CNS) preparations in relation to motor neurons revealed that 19f neurons are recruited into most larval motor programmes. 19f activity lags behind motor neuron activity and as a population, the cells encode spatio-temporal patterns of locomotor activity in the larval CNS. Optogenetic manipulations of 19f cell activity in isolated CNS preparations revealed that they coordinate the activity of central pattern generators underlying exploratory headsweeps and forward locomotion in a context and location specific manner. In behaving animals, activating 19f cells suppressed exploratory headsweeps and slowed forward locomotion, while inhibition of 19f activity potentiated headsweeps, slowing forward movement. Inhibiting activity in 19f cells ultimately affected the ability of larvae to remain in the vicinity of an odor source during an olfactory navigation task. Overall, our findings provide insights into how ascending interneurons monitor motor activity and shape interactions amongst rhythm generators underlying complex navigational tasks.

Predicting Successful Chronic Total Occlusion Crossing With Primary Antegrade Wiring Using Machine Learning.

BACKGROUND: There is limited data on predicting successful chronic total occlusion crossing using primary antegrade wiring (AW). OBJECTIVE: The aim of this study was to develop and validate a machine learning (ML) prognostic model for successful chronic total occlusion crossing using primary AW. METHODS: We used data from 12,136 primary AW cases performed between 2012 and 2023 at 48 centers in the PROGRESS CTO registry (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention; NCT02061436) to develop 5 ML models. Hyperparameter tuning was performed for the model with the best performance, and the SHAP (SHapley Additive exPlanations) explainer was implemented to estimate feature importance. RESULTS: Primary AW was successful in 6,965 cases (57.4%). Extreme gradient boosting was the best performing ML model with an average area under the receiver-operating characteristic curve of 0.775 (± 0.010). After hyperparameter tuning, the average area under the receiver-operating characteristic curve of the extreme gradient boosting model was 0.782 in the training set and 0.780 in the testing set. Among the factors examined, occlusion length had the most significant impact on predicting successful primary AW crossing followed by blunt/no stump, presence of interventional collaterals, vessel diameter, and proximal cap ambiguity. In contrast, aorto-ostial lesion location had the least impact on the outcome. A web-based application for predicting successful primary AW wiring crossing is available online (PROGRESS-CTO website) (https://www.progresscto.org/predict-aw-success). CONCLUSIONS: We developed an ML model with 14 features and high predictive capacity for successful primary AW in chronic total occlusion percutaneous coronary intervention.

Lymphedema Rates Following Axillary Lymph Node Dissection With and Without Immediate Lymphatic Reconstruction: A Prospective Trial.

BACKGROUND: Immediate lymphatic reconstruction (ILR) has been proposed to decrease lymphedema rates. The primary aim of our study was to determine whether ILR decreased the incidence of lymphedema in patients undergoing axillary lymph node dissection (ALND). METHODS: We conducted a two-site pragmatic study of ALND with or without ILR, employing surgeon-level cohort assignment, based on breast surgeons' preferred standard practice. Lymphedema was assessed by limb volume measurements, patient self-reporting, provider documentation, and International Classification of Diseases, Tenth Revision (ICD-10) codes. RESULTS: Overall, 230 patients with breast cancer were enrolled; on an intention-to-treat basis, 99 underwent ALND and 131 underwent ALND with ILR. Of the 131 patients preoperatively planned for ILR, 115 (87.8%) underwent ILR; 72 (62.6%) were performed by one breast surgical oncologist and 43 (37.4%) by fellowship-trained microvascular plastic surgeons. ILR was associated with an increased risk of lymphedema when defined as ≥10% limb volume change on univariable analysis, but not on multivariable analysis, after propensity score adjustment. We did not find a statistically significant difference in limb volume measurements between the two cohorts when including subclinical lymphedema (≥5% inter-limb volume change), nor did we see a difference in grade between the two cohorts on an intent-to-treat or treatment received basis. For all patients, considering ascertainment strategies of patient self-reporting, provider documentation, and ICD-10 codes, as a single binary outcome measure, there was no significant difference in lymphedema rates between those undergoing ILR or not. CONCLUSION: We found no significant difference in lymphedema rates between patients undergoing ALND with or without ILR.

Glutathione-mediated redox regulation in Cryptococcus neoformans impacts virulence.

The fungal pathogen Cryptococcus neoformans is well adapted to its host environment. It has several defence mechanisms to evade oxidative and nitrosative agents released by phagocytic host cells during infection. Among them, melanin production is linked to both fungal virulence and defence against harmful free radicals that facilitate host innate immunity. How C. neoformans manipulates its redox environment to facilitate melanin formation and virulence is unclear. Here we show that the antioxidant glutathione is inextricably linked to redox-active processes that facilitate melanin and titan cell production, as well as survival in macrophages and virulence in a murine model of cryptococcosis. Comparative metabolomics revealed that disruption of glutathione biosynthesis leads to accumulation of reducing and acidic compounds in the extracellular environment of mutant cells. Overall, these findings highlight the importance of redox homeostasis and metabolic compensation in pathogen adaptation to the host environment and suggest new avenues for antifungal drug development.

Modeling cellular responses to serum and vitamin D in microgravity using a human kidney microphysiological system.

The microgravity environment aboard the International Space Station (ISS) provides a unique stressor that can help understand underlying cellular and molecular drivers of pathological changes observed in astronauts with the ultimate goals of developing strategies to enable long- term spaceflight and better treatment of diseases on Earth. We used this unique environment to evaluate the effects of microgravity on kidney proximal tubule epithelial cell (PTEC) response to serum exposure and vitamin D biotransformation capacity. To test if microgravity alters the pathologic response of the proximal tubule to serum exposure, we treated PTECs cultured in a microphysiological system (PT-MPS) with human serum and measured biomarkers of toxicity and inflammation (KIM-1 and IL-6) and conducted global transcriptomics via RNAseq on cells undergoing flight (microgravity) and respective controls (ground). Given the profound bone loss observed in microgravity and PTECs produce the active form of vitamin D, we treated 3D cultured PTECs with 25(OH)D3 (vitamin D) and monitored vitamin D metabolite formation, conducted global transcriptomics via RNAseq, and evaluated transcript expression of CYP27B1, CYP24A1, or CYP3A5 in PTECs undergoing flight (microgravity) and respective ground controls. We demonstrated that microgravity neither altered PTEC metabolism of vitamin D nor did it induce a unique response of PTECs to human serum, suggesting that these fundamental biochemical pathways in the kidney proximal tubule are not significantly altered by short-term exposure to microgravity. Given the prospect of extended spaceflight, more study is needed to determine if these responses are consistent with extended (>6 months) exposure to microgravity.

Leisure-Time Physical Activity Participation in Middle-Aged and Older Adults With a Spinal Cord Injury in Australia.

Objectives: Adults with spinal cord injury (SCI) are often sedentary, increasing their risk of cardiometabolic diseases. Leisure-time Physical Activity (LTPA) is physical activity completed during recreation time for enjoyment. We aimed to quantify LTPA in people ≥45 years with SCI and to explore its relationship with participants' characteristics. Methods: This is a secondary analysis on a subset of the Australian International SCI Survey in participants ≥45 years, at least 12 months post-injury. We described levels of LTPA and used multivariable regressions to estimate the associations between participant characteristics and LTPA. Results: Of 1,281 participants (mean age: 62.7 years, mean time since injury: 18.7 years; 74% males) 44% reported no participation in LTPA. The average LTPA participation was 197 (SD 352) minutes per week (median: 50). Females (ß = -62.3, 95% CI [-112.9, -11.7]), and participants with non-traumatic injuries (ß = -105.2, 95% CI [-165.9, -44.6]) performed less LTPA. Time since injury was not associated with moderate-to-heavy LTPA (LR: Probability > F = 0.785). Conclusion: LTPA promotion in the SCI population ≥45 years focusing on females and non-traumatic injuries is warranted.

External skeletal fixation for the treatment of pelvic fractures in cats.

OBJECTIVE: To report the technique and the outcome for the repair of pelvic fractures in cats using external skeletal fixation (ESF). STUDY DESIGN: Retrospective case series. ANIMALS: Client-owned cats (n = 125). METHODS: Medical records of cats with pelvic fractures, treated with an ESF between June 2001 and June 2009, were reviewed. Preoperative, immediate postoperative, and more than 4 weeks' postoperative radiographs were compared. Clinical examination was performed 4 to 9 weeks following surgery. Longer term follow up (4 to 80 months) was conducted by client questionnaire. RESULTS: No intraoperative complications occurred. There was no change in the pelvic canal width observed on follow-up radiographs (p = .16). Implant loosening was noted on follow-up radiographs in 16/125 (13%) of cases, and 67/803 (8%) pins were palpably loose at the time of frame removal. The mean time to frame removal was 37 ± 9 days. No long-term complications were reported. Long-term mean mobility score was 95 ± 5 and median lameness was 0 (range: 0-2). CONCLUSION: An ESF may be successfully applied for the stabilization of various pelvic fractures in cats. CLINICAL SIGNIFICANCE: The application of an ESF for the management of pelvic fractures in cats provides good outcomes.

Two C-terminal isoforms of Aplysia tachykinin-related peptide receptors exhibit phosphorylation-dependent and independent desensitization mechanisms.

Diversity, a hallmark of G protein-coupled receptor (GPCR) signaling, partly stems from alternative splicing of a single gene generating more than one isoform for a receptor. Additionally, receptor responses to ligands can be attenuated by desensitization upon prolonged or repeated ligand exposure. Both phenomena have been demonstrated and exemplified by the deuterostome tachykinin (TK) signaling system, although the role of phosphorylation in desensitization remains a subject of debate. Here, we describe the signaling system for tachykinin-related peptides (TKRPs) in a protostome, mollusk Aplysia. We cloned the Aplysia TKRP precursor, which encodes three TKRPs (apTKRP-1, apTKRP-2a, and apTKRP-2b) containing the FXGXR-amide motif. In situ hybridization and immunohistochemistry showed predominant expression of TKRP mRNA and peptide in the cerebral ganglia. TKRPs and their post-translational modifications were observed in extracts of CNS ganglia using mass spectrometry. We identified two Aplysia TKRP receptors (TKRPRs), named apTKRPR-A and apTKRPR-B. These receptors are two isoforms generated through alternative splicing of the same gene and differ only in their intracellular C-termini. Structure-activity relationship analysis of apTKRP-2b revealed that both C-terminal amidation and conserved residues of the ligand are critical for receptor activation. C-terminal truncates and mutants of apTKRPRs suggested that there is a C-terminal phosphorylation-independent desensitization for both receptors. Moreover, apTKRPR-B also exhibits phosphorylation-dependent desensitization through the phosphorylation of C-terminal Ser/Thr residues. This comprehensive characterization of the Aplysia TKRP signaling system underscores the evolutionary conservation of the TKRP and TK signaling systems, while highlighting the intricacies of receptor regulation through alternative splicing and differential desensitization mechanisms.

RNAi-mediated silencing of SOD1 profoundly extends survival and functional outcomes in ALS mice.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative condition, with 20% of familial and 2-3% of sporadic cases linked to mutations in the cytosolic superoxide dismutase (SOD1) gene. Mutant SOD1 protein is toxic to motor neurons, making SOD1 gene lowering a promising approach, supported by preclinical data and the 2023 FDA approval of the GapmeR ASO targeting SOD1, tofersen. Despite the approval of an ASO and the optimism it brings to the field, the pharmacodynamics and pharmacokinetics of therapeutic SOD1 modulation can be improved. Here, we developed a chemically stabilized divalent siRNA scaffold (di-siRNA) that effectively suppresses SOD1 expression in vitro and in vivo. With optimized chemical modification, it achieves remarkable CNS tissue permeation and SOD1 silencing in vivo. Administered intraventricularly, di-siRNASOD1 extended survival in SOD1-G93A ALS mice, surpassing survival previously seen in these mice by ASO modalities, slowed disease progression, and prevented ALS neuropathology. These properties offer an improved therapeutic strategy for SOD1-mediated ALS and may extend to other dominantly inherited neurological disorders.

The effect of single low-dose primaquine treatment for uncomplicated Plasmodium falciparum malaria on haemoglobin levels in Ethiopia: a longitudinal cohort study.

BACKGROUND: To interrupt residual malaria transmission and achieve successful elimination of Plasmodium falciparum in low-transmission settings, the World Health Organization (WHO) recommends the administration of a single dose of 0.25 mg/kg (or 15 mg/kg for adults) primaquine (PQ) combined with artemisinin-based combination therapy (ACT), without glucose-6-phosphate dehydrogenase (G6PD) testing. However, due to the risk of haemolysis in patients with G6PD deficiency (G6PDd), PQ use is uncommon. Thus, this study aimed to assess the safety of a single low dose of PQ administered to patients with G6PD deficiency. METHODS: An observational cohort study was conducted with patients treated for uncomplicated P. falciparum malaria with either single-dose PQ (0.25 mg/kg) (SLD PQ) + ACT or ACT alone. Microscopy-confirmed uncomplicated P. falciparum malaria patients visiting public health facilities in Arjo Didessa, Southwest Ethiopia, were enrolled in the study from September 2019 to November 2022. Patients with uncomplicated P. falciparum malaria were followed up for 28 days through clinical and laboratory diagnosis, such as measurements of G6PD levels and haemoglobin (Hb) concentrations. G6PD levels were measured by a quantiative CareSTART™ POCT S1 biosensor machine. Patient interviews were also conducted, and the type and frequency of clinical complaints were recorded. Hb data were taken on days (D) 7, 14, 21, and 28 following treatment with SLD-PQ + ACT or ACT alone. RESULTS: A total of 249 patients with uncomplicated P. falciparum malaria were enrolled in this study. Of these, 83 (33.3%) patients received ACT alone, and 166 (66.7%) received ACT combined with SLD-PQ treatment. The median age of the patients was 20 (IQR 28-15) years. G6PD deficiency was found in 17 (6.8%) patients, 14 males and 3 females. There were 6 (7.2%) and 11 (6.6%) phenotypic G6PD-deficient patients in the ACT alone and ACT + SLD-PQ arms, respectively. The mean Hb levels in patients treated with ACT + SLD-PQ were reduced by an average of 0.45 g/dl (95% CI = 0.39 to 0.52) in the posttreatment phase (D7) compared to a reduction of 0.30 g/dl (95% CI = 0.14 to - 0.47) in patients treated with ACT alone (P = 0.157). A greater mean Hb reduction was observed on day 7 in the G6PDd ACT + SLD-PQ group (- 0.60 g/dL) than in the G6PDd ACT alone group (- 0.48 g/dL); however, there was no statistically significant difference (P = 0.465). Overall, D14 losses were 0.10 g/dl (95% CI = - 0.00 to 0.20) and 0.05 g/dl (95% CI = - 0.123 to 0.22) in patients with and without SLD-PQ, respectively (P = 0.412). CONCLUSIONS: This study's findings indicate that using SLD-PQ in combination with ACT is safe for uncomplicated P. falciparum malaria regardless of the patient's G6PD status in Ethiopian settings. Caution should be taken in extrapolating this finding in other settings with diverse G6DP phenotypes.

Cross-correlated relaxation in the NMR of near-equivalent spin pairs: Longitudinal relaxation and long-lived singlet order.

The evolution of nuclear spin state populations is investigated for the case of a 13C2-labeled triyne in solution, for which the near-equivalent coupled pairs of 13C nuclei experience cross-correlated relaxation mechanisms. Inversion-recovery experiments reveal different recovery curves for the main peak amplitudes, especially when the conversion of population imbalances to observable coherences is induced by a radio frequency pulse with a small flip angle. Measurements are performed over a range of magnetic fields by using a sample shuttle apparatus. In some cases, the time constant TS for decay of nuclear singlet order is more than 100 times larger than the time constant T1 for the equilibration of longitudinal magnetization. The results are interpreted by a theoretical model incorporating cross-correlated relaxation mechanisms, anisotropic rotational diffusion, and an external random magnetic field. A Lindbladian formalism is used to describe the dissipative dynamics of the spin system in an environment of finite temperature. Good agreement is achieved between theory and experiment.

Efficacy, tolerability, and bone density outcomes of elagolix with add-back therapy for endometriosis-associated pain: 12 months of an ongoing randomized phase 3 trial.

BACKGROUND: Elagolix, an approved oral treatment for endometriosis-associated pain, has been associated with hypoestrogenic effects when used as monotherapy. Hormonal add-back therapy has the potential to mitigate these effects. OBJECTIVE: To evaluate efficacy, tolerability, and bone density outcomes of elagolix 200 mg twice daily with 1 mg estradiol /0.5 mg norethindrone acetate (add-back) therapy once daily compared with placebo in premenopausal women with moderate-to-severe endometriosis-associated pain. STUDY DESIGN: This ongoing, 48-month, phase 3 study consists of a 12-month, double-blind period, with randomization 4:1:2 to elagolix 200 mg twice daily with add-back therapy, elagolix 200 mg twice daily monotherapy for 6 months followed by elagolix with add-back therapy, or placebo. The co-primary endpoints were proportion of patients with clinical improvement (termed "responders") in dysmenorrhea and nonmenstrual pelvic pain at month 6. We report 12-month results on efficacy of elagolix with add-back therapy versus placebo in reducing dysmenorrhea, nonmenstrual pelvic pain, dyspareunia, and fatigue. Tolerability assessments include adverse events and change from baseline in bone mineral density. RESULTS: A total of 679 patients were randomized to elagolix with add-back therapy (n=389), elagolix monotherapy (n=97), or placebo (n=193). Compared with patients randomized to placebo, a significantly greater proportion of patients randomized to elagolix with add-back therapy responded with clinical improvement in dysmenorrhea (62.8% versus 23.7%; P≤.001) and nonmenstrual pelvic pain (51.3% versus 36.8%; P≤.001) at 6 months. Compared with placebo, elagolix with add-back therapy produced significantly greater improvement from baseline in 7 hierarchically ranked secondary endpoints including dysmenorrhea (months 12, 6, 3), nonmenstrual pelvic pain (months 12, 6, 3), and fatigue (months 6) (all P<.01). Overall, the incidence of adverse events was 73.8% with elagolix plus add-back therapy and 66.8% with placebo. The rate of severe and serious adverse events did not meaningfully differ between treatment groups. Study drug discontinuations associated with adverse events were low in patients receiving elagolix with add-back therapy (12.6%) and those receiving placebo (9.8%). Patients randomized to elagolix monotherapy exhibited decreases from baseline in bone mineral density of -2.43% (lumbar spine), -1.54% (total hip), and -1.78% (femoral neck) at month 6. When add-back therapy was added to elagolix at month 6, the change from baseline in bone mineral density remained in a similar range of -1.58% to -1.83% at month 12. However, patients who received elagolix plus add-back therapy from baseline exhibited little change from baseline in bone mineral density (<1% change) at months 6 and 12. CONCLUSION: Compared with placebo, elagolix with add-back therapy resulted in significant, clinically meaningful improvement in dysmenorrhea, nonmenstrual pelvic pain, and fatigue at 6 months that continued until month 12 for both dysmenorrhea and nonmenstrual pelvic pain. Elagolix with add-back therapy was generally well tolerated. Loss of bone mineral density at 12 months was greater in patients who received elagolix with add-back therapy than those who received placebo. However, the change in bone mineral density with elagolix plus add-back therapy was < 1% and was attenuated compared with bone loss observed with elagolix monotherapy.

Study protocol for a prospective, multicentre study of hypercortisolism in patients with difficult-to-control type 2 diabetes (CATALYST): prevalence and treatment with mifepristone.

INTRODUCTION: Even with recent treatment advances, type 2 diabetes (T2D) remains poorly controlled for many patients, despite the best efforts to adhere to therapies and lifestyle modifications. Although estimates vary, studies indicate that in >10% of individuals with difficult-to-control T2D, hypercortisolism may be an underlying contributing cause. To better understand the prevalence of hypercortisolism and the impact of its treatment on T2D and associated comorbidities, we describe the two-part Hyper c ortisolism in P at ients with Difficult to Control Type 2 Di a betes Despite Receiving Standard-of-Care Therapies: Preva l ence and Treatment with Korl y m® (Mifepri st one) (CATALYST) trial. METHODS AND ANALYSIS: In part 1, approximately 1000 participants with difficult-to-control T2D (haemoglobin A1c (HbA1c) 7.5%-11.5% despite multiple therapies) are screened with a 1 mg dexamethasone suppression test (DST). Those with post-DST cortisol >1.8 µg/dL and dexamethasone level ≥140 ng/dL are identified to have hypercortisolism (part 1 primary endpoint), have morning adrenocorticotropic hormone (ACTH) and dehydroepiandrosterone sulfate (DHEAS) measured and undergo a non-contrast adrenal CT scan. Those requiring evaluation for elevated ACTH are referred for care outside the study; those with ACTH and DHEAS in the range may advance to part 2, a randomised, double-blind, placebo-controlled trial to evaluate the impact of treating hypercortisolism with the competitive glucocorticoid receptor antagonist mifepristone (Korlym®). Participants are randomised 2:1 to mifepristone or placebo for 24 weeks, stratified by the presence/absence of an abnormal adrenal CT scan. Mifepristone is dosed at 300 mg once daily for 4 weeks, then 600 mg daily based on tolerability and clinical improvement, with an option to increase to 900 mg. The primary endpoint of part 2 assesses changes in HbA1c in participants with hypercortisolism with or without abnormal adrenal CT scan. Secondary endpoints include changes in antidiabetes medications, cortisol-related comorbidities and quality of life. ETHICS AND DISSEMINATION: The study has been approved by Cleveland Clinic IRB (Cleveland, Ohio, USA) and Advarra IRB (Columbia, Maryland, USA). Findings will be presented at scientific meetings and published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT05772169.

Lipoprotein(a) and Calcific Aortic Valve Stenosis Progression: A Systematic Review and Meta-Analysis.

Importance: There are currently no pharmacological treatments available to slow hemodynamic progression of aortic stenosis. Plasma lipoprotein(a) concentrations predict incident aortic stenosis but its association with hemodynamic progression is controversial. Objective: To determine the association between plasma lipoprotein(a) concentrations and hemodynamic progression in patients with aortic stenosis. Design, Settings and Participants: The study included patients with aortic stenosis from 5 longitudinal clinical studies conducted from March 2001 to March 2023 in Canada and the UK. Of 757 total patients, data on plasma lipoprotein(a) concentrations and rates of hemodynamic progression assessed by echocardiography were available for 710, who were included in this analysis. Data were analyzed from March 2023 to April 2024. Exposure: Cohort-specific plasma lipoprotein(a) concentration tertiles. Main Outcomes and Measures: Hemodynamic aortic stenosis progression on echocardiography as assessed by annualized change in peak aortic jet velocity, mean transvalvular gradient, and aortic valve area. Results: Among the included patients, 497 (70%) were male and 213 (30%) were female. The mean (SD) age was 65.2 (13.1) years. Patients in the top lipoprotein(a) tertile demonstrated 41% (estimate, 1.41; 95% CI, 1.13-1.75) faster progression of peak aortic jet velocity and 57% (estimate, 1.57; 95% CI, 1.18-2.10) faster progression of mean transvalvular gradient than patients in the bottom tertile. There was no evidence of heterogeneity across the individual cohorts. Progression of aortic valve area was comparable between groups (estimate, 1.23; 95% CI, 0.71-2.12). Similar results were observed when plasma lipoprotein(a) concentrations were treated as a continuous variable. Conclusions and Relevance: In this study, higher plasma lipoprotein(a) concentrations were associated with faster rates of hemodynamic progression in patients with aortic stenosis. Lowering plasma lipoprotein(a) concentrations warrants further investigation in the prevention and treatment of aortic stenosis.

Hypothesis: the generation of T cells directed against neoepitopes employing immune-mediating agents other than neoepitope vaccines.

The development of vaccines, especially RNA-based, directed against patient-specific tumor neoepitopes is an active and productive area of cancer immunotherapy. Promising clinical results in melanoma and other solid tumor types are emerging. As with all cancer therapy modalities, neoepitope vaccine development and delivery also has some drawbacks, including the level of effort to develop a patient-specific product, accuracy of algorithms to predict neoepitopes, and with the exception of melanoma and some other tumor types, biopsies of metastatic lesions of solid tumors are often not available. We hypothesize that in some circumstances the use of rationally designed combinations of "off-the-shelf" agents may prove an additional path to enable the patient to produce his/her own "neoepitope vaccine" in situ. These combination therapies may consist of agents to activate a tumor-associated T-cell response, potentiate that response, reduce or eliminate immunosuppressive entities in the tumor microenvironment, and/or alter the phenotype of tumor cells to render them more susceptible to immune-mediated lysis. Examples are provided in both preclinical and clinical studies in which combinations of "off-the-shelf" agents lead to the generation of T cells directed against tumor-derived neoepitopes with consequent antitumor activity.

Clinical Characteristics, Outcomes, and Interobserver Agreement of Point-of-Care Ultrasound Detected Mesenteric Adenitis in Nonsurgical Pediatric Abdominal Pain: A Retrospective Cohort Study.

OBJECTIVES: Point-of-care ultrasound (PoCUS) in the emergency department (ED) may facilitate the diagnosis of nonsurgical sources of abdominal pain after surgical causes are excluded. Identifying mesenteric adenitis is a feasible PoCUS application due to its ease of use and speed. However, there are scant data regarding the diagnosis of mesenteric adenitis by PoCUS. The objective of this study was to describe the clinical characteristics, outcomes, and interobserver agreement of mesenteric adenitis identified on PoCUS in pediatric patients with nonsurgical abdominal pain. METHODS: This was a retrospective review at a tertiary-care, urban pediatric ED. All cases of mesenteric adenitis diagnosed on PoCUS from January 2018 to August 2022 were reviewed. Demographics and clinical data, including relevant outcomes, were recorded. All PoCUS videos were reviewed by a senior sonologist-physician for determination of mesenteric adenitis in children 21 years and younger with nonsurgical abdominal pain. Interobserver agreement by Cohen κ was calculated between experienced and novice physician sonologists blinded to diagnosis, who reviewed 77 six-second video clips for presence or absence of mesenteric adenitis. RESULTS: Thirty-three subjects were identified by PoCUS to have mesenteric adenitis in the setting of nonsurgical abdominal pain presenting to our ED. Most common indications for PoCUS were for suspected appendicitis, suspected intussusception, or undifferentiated abdominal pain. Forty-six percent of patients were male; median age was 9 years (interquartile range, 4-14 years). On 4-week clinical follow-up, 1 patient returned to our ED with a surgical abdomen. Cohen κ values were 0.83 (95% confidence interval, 0.70-0.97) between experienced sonologist-physicians and 0.76 (95% confidence interval, 0.61-.90) between novice and experienced sonologist-physicians. CONCLUSIONS: PoCUS can identify mesenteric adenitis, typically a diagnosis of exclusion, in pediatric patients with nonsurgical abdominal pain, both by novice and experienced physician-sonologists. Use of PoCUS may help ED clinicians identify a common cause of nonsurgical abdominal pain in children.

The crystal structure of Shethna protein II (FeSII) from Azotobacter vinelandii suggests a domain swap.

The Azotobacter vinelandii FeSII protein forms an oxygen-resistant complex with the nitrogenase MoFe and Fe proteins. FeSII is an adrenodoxin-type ferredoxin that forms a dimer in solution. Previously, the crystal structure was solved [Schlesier et al. (2016), J. Am. Chem. Soc. 138, 239-247] with five copies in the asymmetric unit. One copy is a normal adrenodoxin domain that forms a dimer with its crystallographic symmetry mate. The other four copies are in an `open' conformation with a loop flipped out exposing the 2Fe-2S cluster. The open and closed conformations were interpreted as oxidized and reduced, respectively, and the large conformational change in the open configuration allowed binding to nitrogenase. Here, the structure of FeSII was independently solved in the same crystal form. The positioning of the atoms in the unit cell is similar to the earlier report. However, the interpretation of the structure is different. The `open' conformation is interpreted as the product of a crystallization-induced domain swap. The 2Fe-2S cluster is not exposed to solvent, but in the crystal its interacting helix is replaced by the same helix residues from a crystal symmetry mate. The domain swap is complicated, as it is unusual in being in the middle of the protein rather than at a terminus, and it creates arrangements of molecules that can be interpreted in multiple ways. It is also cautioned that crystal structures should be interpreted in terms of the contents of the entire crystal rather than of one asymmetric unit.

Computational Insights into Amide Bond Formation Catalyzed by the Condensation Domain of Nonribosomal Peptide Synthetases.

Nonribosomal peptide synthetases (NRPSs) are important enzymes that synthesize an array of nongenetically encoded peptides. The latter have diverse physicochemical properties and roles. NRPSs are modular enzymes in which, for example, the condensation (C-) domain catalyzes the formation of amide bonds. The NRPS tyrocidine synthetase from Brevibacillus brevis is responsible for synthesizing the cyclic-peptide antibiotic tyrocidine. The first step is formation of an amide bond between a proline and phenylalanine which is catalyzed by a C-domain. In this study, a multiscale computational approach (molecular dynamics and QM/MM) has been used to investigate substrate binding and catalytic mechanism of the C-domain of tyrocidine synthetase. Overall, the mechanism is found to proceed through three exergonic steps in which an active site Histidine, His222, acts as a base and acid. First, His222 acts as a base to facilitate nucleophilic attack of the prolyl nitrogen at the phenylalanyl's carbonyl carbon. This is also the rate-limiting step with a free energy barrier of 38.8 kJ mol-1. The second step is collapse of the resulting tetrahedral intermediate with cleavage of the S-C bond between the phenylalanyl and its Ppant arm, along with formation of the above amide bond. Meanwhile, the now protonated His222 imidazole has rotated toward the newly formed thiolate of the Ppant arm. In the final step, His222 acts as an acid, protonating the thiolate and regenerating a neutral His222. The overall mechanism is found to be exergonic with the final product complex being 46.3 kJ mol-1 lower in energy than the initial reactant complex.