G-quadruplexes are a source of vulnerability in BRCA2 deficient granule cell progenitors and medulloblastoma.

Biallelic pathogenic variants in the essential DNA repair gene BRCA2 causes Fanconi anemia, complementation group FA-D1. Patients in this group are highly prone to develop embryonal tumors, most commonly medulloblastoma arising from the cerebellar granule cell progenitors (GCPs). GCPs undergo high proliferation in the postnatal cerebellum under SHH activation, but the type of DNA lesions that require the function of the BRCA2 to prevent tumorigenesis remains unknown. To identify such lesions, we assessed both GCP neurodevelopment and tumor formation using a mouse model with deletion of exons three and four of Brca2 in the central nervous system, coupled with global Trp53 loss. Brca2 Δex3-4 ;Trp53 -/- animals developed SHH subgroup medulloblastomas with complete penetrance. Whole-genome sequencing of the tumors identified structural variants with breakpoints enriched in areas overlapping G-quadruplexes (G4s). Brca2-deficient GCPs exhibited decreased replication speed in the presence of the G4-stabilizer pyridostatin. Pif1 helicase, which resolves G4s during replication, was highly upregulated in tumors, and Pif1 knockout in primary MB tumor cells resulted in increased genome instability upon pyridostatin treatment. These data suggest that G4s may represent sites prone to replication stalling in highly proliferative GCPs and without BRCA2, G4s become a source of genome instability. Tumor cells upregulate G4-resolving helicases to facilitate rapid proliferation through G4s highlighting PIF1 helicase as a potential therapeutic target for treatment of BRCA2-deficient medulloblastomas.

Greater Socioeconomic Deprivation is Associated with Increased Complication Rates and Lower Patient-Reported Outcomes Following Open Reduction and Internal Fixation of Humeral Shaft Fractures.

OBJECTIVES: This study explored the hypothesis that social determinants of health (SDOH), including racial and economic differences, may impact orthopaedic trauma outcomes in patients undergoing open reduction and internal fixation (ORIF) of humeral shaft fractures. METHODS: Design: Retrospective. SETTING: Single, academic, tertiary Level-I trauma center. PATIENT SELECTION CRITERIA: Adults with midshaft humerus fractures (AO/OTA 12) treated operatively with plate fixation from 05/2011 to 05/2021 with a minimum follow-up of nine months. OUTCOME MEASURES AND COMPARISONS: Radiographic fracture healing, complication rates, and patient-reported outcomes were investigated. SDOH were assessed using the Area Deprivation Index (ADI). Demographics, complications rates, and patient-reported clinical outcomes were compared between the first and fourth ADI quartiles. RESULTS: 196 patients fit the study criteria. The average age of the cohort was 47 years with 50 women (51%). Comparisons of the least deprived quartile (n=49) to the most deprived quartile (n=49) yielded similar sex distribution (59% vs 43% female, p=0.15), fewer non-white patients (8% vs 51%, p<0.01), older average age (51 years vs 43 years, p=0.05), similar BMI (30.5 vs. 31.8, p=0.45), and higher Charlson Comorbidity Index (CCI) (2.2 vs.1.1, p=0.03). While nonunion rates were similar (p=0.20) between groups, the most deprived quartile had 2.3 times greater odds of post-operative complications (p=0.04). Patients in the most deprived group exhibited higher PROMIS Pain Interference (PI) scores (p<0.01) and PROMIS Depression (D) scores (p=0.01), with lower PROMIS Physical Function (PF) scores (p<0.01) at 6-month follow-up than the least depriver cohort. The most deprived cohort had three times higher odds of missing scheduled appointments within the first post-operative year (p<0.01), resulting in a significantly higher no-show rate (p<0.01) than the least deprived cohort. Regression analysis including several demographic and injury factors identified that ADI was significantly associated with the occurrence of any missed appointments (p<0.01), no-show rates (p=0.04), and experiencing one of the following post-operative complications during recovery: Nonunion, radial nerve injury, or dysfunction (p=0.03). CONCLUSIONS: Patients experiencing greater resource deprivation faced increased odds of complications, missed appointments, and poorer PROMIS outcomes following humeral shaft fracture fixation, emphasizing that baseline socioeconomic disparities predict unfavorable post-operative outcomes even given favorable baseline health status according to the CCI score. LEVEL OF EVIDENCE: Level III. See Instructions for Authors for a complete description of levels of evidence.

Temporary Vocal Fold Augmentation Outcomes for Refractory Chronic Cough with Concurrent Nonparalytic Glottic Insufficiency due to Vocal Fold Atrophy.

OBJECTIVE: Determine the effect of temporary vocal fold augmentation on refractory chronic cough (RCC) in patients with glottic insufficiency (GI) due to vocal fold atrophy. METHODS: Retrospective electronic chart review was conducted for patients with a diagnosis of bilateral vocal fold atrophy and RCC undergoing vocal fold augmentation with carboxymethylcellulose (CMC). Patients with vocal fold immobility were excluded, and cough must have been present for at minimum 8weeks. VHI-10, CSI, and RSI scores along with subjective overall patient report of chronic cough improvement were collected. RESULTS: A total of 28 patients underwent 30 vocal fold augmentation procedures with CMC. All had undergone extensive cough work-up and treatment trials prior to their augmentation procedure. From chart review, 13 overall subjectively reported satisfactory improvement in their cough, 5 reported partial improvement, and 7 reported no improvement in their cough. An uncertain effect on cough was documented in 5 (either patient was uncertain or no mention of cough symptom in the interval chart history note). For those subjects with both pre- and post-augmentation data, mean preaugmentation CSI: 22.08± 6.8 (n = 13); VHI-10: 13.6± 8.9 (n = 18); RSI: 22.4± 7.5 (n = 17). Mean postaugmentation CSI was 20.7± 9.2 (n = 13); VHI-10: 15.2± 8.2 (n = 18); RSI: 21.1± 5.8 (n = 17). Mean pre-post change in CSI was -1.4± 5.1 (P = 0.175, n = 13, range -10 to +6). CONCLUSIONS: Vocal fold augmentation seems to provide subjective cough improvement in some patients with concurrent GI due to vocal fold atrophy and RCC. It can be offered as a diagnostic trial, on which further augmentation may be offered, for patients with persistent cough despite prior work-up and treatment trials. Further controlled prospective studies are needed to identify factors that are predictive of successful cough improvement following vocal fold augmentation, as well as the effect of durable augmentation in those patients who had improvement with a diagnostic trial.

Quantifying Spatial Patterns of Tissue Stiffness Within the Embryonic Mouse Kidney.

Biophysical factors, including changes in mechanical stiffness, have been shown to influence the morphogenesis of developing organs. There is a lack of experimental techniques, however, that can probe the mechanical properties of embryonic tissues-especially those which are not mechanically or optically accessible, such as the visceral organs of the developing mouse embryo. Here, using the embryonic kidney as a model system, we describe a method to use microindentation to quantify tissue-level regional differences in the mechanical properties of an embryonic organ. This technique is generalizable and can be used to quantify patterns of tissue stiffness within other developing organ systems. Going forward, these data will enable new experimental studies of the role of biophysical cues during organogenesis.

VCP/p97-associated proteins are binders and debranching enzymes of K48-K63-branched ubiquitin chains.

Branched ubiquitin (Ub) chains constitute a sizable fraction of Ub polymers in human cells. Despite their abundance, our understanding of branched Ub function in cell signaling has been stunted by the absence of accessible methods and tools. Here we identify cellular branched-chain-specific binding proteins and devise approaches to probe K48-K63-branched Ub function. We establish a method to monitor cleavage of linkages within complex Ub chains and unveil ATXN3 and MINDY as debranching enzymes. We engineer a K48-K63 branch-specific nanobody and reveal the molecular basis of its specificity in crystal structures of nanobody-branched Ub chain complexes. Using this nanobody, we detect increased K48-K63-Ub branching following valosin-containing protein (VCP)/p97 inhibition and after DNA damage. Together with our discovery that multiple VCP/p97-associated proteins bind to or debranch K48-K63-linked Ub, these results suggest a function for K48-K63-branched chains in VCP/p97-related processes.

Clinicians' Perspectives on the Telehealth Serious Illness Care Program for Older Adults With Myeloid Malignancies: Single-Arm Pilot Study.

BACKGROUND: Serious illness conversations may help patients avoid unwanted treatments. We previously piloted the telehealth Serious Illness Care Program (SICP) for older adults with acute myeloid leukemia and myelodysplastic syndrome. OBJECTIVE: In this study, we aimed to understand the experience of the telehealth SICP from the clinician's perspective. METHODS: We studied 10 clinicians who delivered the telehealth SICP to 20 older adults with acute myeloid leukemia or myelodysplastic syndrome. Quantitative outcomes included confidence and acceptability. Confidence was measured using a 22-item survey (range 1-7; a higher score is better). Acceptability was measured using an 11-item survey (5-point Likert scale). Hypothesis testing was performed at α=.10 (2-tailed) due to the pilot nature and small sample size. Clinicians participated in audio-recorded qualitative interviews at the end of the study to discuss their experience. RESULTS: A total of 8 clinicians completed the confidence measure and 7 clinicians completed the acceptability measure. We found a statistically significant increase in overall confidence (mean increase of 0.5, SD 0.6; P=.03). The largest increase in confidence was in helping families with reconciliation and goodbye (mean 1.4, SD 1.5; P=.04). The majority of clinicians agreed that the format was simple (6/7, 86%) and easy to use (6/7, 86%). Clinicians felt that the telehealth SICP was effective in understanding their patients' values about end-of-life care (7/7, 100%). A total of three qualitative themes emerged: (1) the telehealth SICP deepened relationships and renewed trust; (2) each telehealth SICP visit felt unique and personal in a positive way; and (3) uninterrupted, unrushed time optimized the visit experience. CONCLUSIONS: The telehealth SICP increased confidence in having serious illness conversations while deepening patient-clinician relationships. TRIAL REGISTRATION: ClinicalTrials.gov NCT04745676; https://www.clinicaltrials.gov/study/NCT04745676.

Cancer-associated Histone H3 N-terminal arginine mutations disrupt PRC2 activity and impair differentiation.

Dysregulated epigenetic states are a hallmark of cancer and often arise from genetic alterations in epigenetic regulators. This includes missense mutations in histones, which, together with associated DNA, form nucleosome core particles. However, the oncogenic mechanisms of most histone mutations are unknown. Here, we demonstrate that cancer-associated histone mutations at arginines in the histone H3 N-terminal tail disrupt repressive chromatin domains, alter gene regulation, and dysregulate differentiation. We find that histone H3R2C and R26C mutants reduce transcriptionally repressive H3K27me3. While H3K27me3 depletion in cells expressing these mutants is exclusively observed on the minor fraction of histone tails harboring the mutations, the same mutants recurrently disrupt broad H3K27me3 domains in the chromatin context, including near developmentally regulated promoters. H3K27me3 loss leads to de-repression of differentiation pathways, with concordant effects between H3R2 and H3R26 mutants despite different proximity to the PRC2 substrate, H3K27. Functionally, H3R26C-expressing mesenchymal progenitor cells and murine embryonic stem cell-derived teratomas demonstrate impaired differentiation. Collectively, these data show that cancer-associated H3 N-terminal arginine mutations reduce PRC2 activity and disrupt chromatin-dependent developmental functions, a cancer-relevant phenotype.

Chemo-Phosphoproteomic Profiling with ATR Inhibitors Berzosertib and Gartisertib Uncovers New Biomarkers and DNA Damage Response Regulators.

The ATR kinase protects cells against DNA damage and replication stress and represents a promising anti-cancer drug target. The ATR inhibitors (ATRi) berzosertib and gartisertib are both in clinical trials for the treatment of advanced solid tumors as monotherapy or in combination with genotoxic agents. We carried out quantitative phospho-proteomic screening for ATR biomarkers that are highly sensitive to berzosertib and gartisertib, using an optimized mass spectrometry pipeline. Screening identified a range of novel ATR-dependent phosphorylation events, which were grouped into three broad classes: (i) targets whose phosphorylation is highly sensitive to ATRi and which could be the next generation of ATR biomarkers; (ii) proteins with known genome maintenance roles not previously known to be regulated by ATR; (iii) novel targets whose cellular roles are unclear. Class iii targets represent candidate DNA damage response proteins and, with this in mind, proteins in this class were subjected to secondary screening for recruitment to DNA damage sites. We show that one of the proteins recruited, SCAF1, interacts with RNAPII in a phospho-dependent manner and recruitment requires PARP activity and interaction with RNAPII. We also show that SCAF1 deficiency partly rescues RAD51 loading in cells lacking the BRCA1 tumor suppressor. Taken together these data reveal potential new ATR biomarkers and new genome maintenance factors.

Clinical and Radiographic Outcomes Following Volar-Locked Plating Versus Dorsal Bridge Plating for Distal Radius Factures.

Purpose: Distal radius fractures (DRFs) indicated for operative intervention are most commonly treated with volar-locked plating (VLP); however, dorsal bridge plating (DBP) has been used as an alternative fixation method. The purpose of this study was to use a propensity score to match and compare the radiographic and clinical outcomes of patients undergoing isolated VLP or DBP for DRFs. Methods: We performed a retrospective, propensity score-matched analysis of patients undergoing isolated VLP or DBP treatment for isolated DRFs from 2015 to 2022 at a single level-1 trauma center. Patients were propensity score-matched by a total of eight demographic and comorbidity factors, AO Foundation/Orthopedic Trauma Association classification, and preoperative Patient-Reported Outcomes Measurement Information System (PROMIS) scores. Our primary outcomes included postoperative complications, wrist and forearm range of motion (ROM), grip strength, and radiographic measurements, including radial height, radial inclination, volar tilt, and articular step-off. Results: Overall, 415 DBP and 2075 VLP were successfully propensity score-matched and included in this study. Grip strength and ROM measurements at the 6-month follow-up, including wrist flexion, wrist extension, forearm pronation, forearm supination, radial deviation, and ulnar deviation, were increased in the VLP compared with DBP (P < .05). Complication rates among both the groups were relatively low; however, the rates of malunion and nonunion were significantly higher among the DBP group (P < .05). Radial height, radial inclination, and articular step-off were improved in the VLP group compared with the DBP group (P < .05); however, volar tilt was similar between groups. PROMIS upper extremity and physical function were significantly higher among the VLP group (P < .05). No significant difference was noted in PROMIS pain interference between the groups. Conclusions: When compared with DBP, patients undergoing VLP are more likely to have improved clinical and radiographic outcomes. Although improvement in wrist and forearm ROM and radiographic parameters is statistically significant, it may not be clinically relevant. Type of study/level of evidence: Therapeutic III.

Epithelial tubule interconnection driven by HGF-Met signaling in the kidney.

The formation of functional epithelial tubules is a central feature of many organ systems. Although the process of tubule formation by epithelial cells is well-studied, the way in which tubules connect with each other (i.e. anastomose) to form functional networks both in vivo and in vitro is not well understood. A key, unanswered question in the kidney is how the renal vesicles of the embryonic kidney connect with the nascent collecting ducts to form a continuous urinary system. We performed a ligand-receptor pair analysis on single cell RNA-seq data from embryonic mouse kidney tubules undergoing anastomosis to select candidates that might mediate this process in vivo. This analysis identified hepatocyte growth factor (HGF), which has known roles in cell proliferation, migration, and tubulogenesis, as one of several possible candidates. To test this possibility, we designed a novel assay to quantitatively examine epithelial tubule anastomosis in vitro using epithelial spheroids with fluorescently-tagged apical surfaces to enable direct visualization of anastomosis. This revealed that HGF is a potent inducer of tubule anastomosis. Tubule anastomosis occurs through a proliferation-independent mechanism that acts through the MAPK signaling cascade and matrix metalloproteinases (MMPs), the latter suggestive of a role in extracellular matrix turnover. Accordingly, treatment of explanted embryonic mouse kidneys with HGF and collagenase was sufficient to induce kidney tubule anastomosis. These results lay the groundwork for investigating how to promote functional interconnections between tubular epithelia, which have important clinical implications for utilizing in vitro grown kidney tissue in transplant medicine.

Operative treatment of Mason Type III radial head fractures - A comparative analysis using PROMIS.

Objectives: The purpose of this study is to evaluate the outcomes of operatively treated Mason Type III radial head fractures. Additionally, this project seeks to assess efficacy of PROMIS in evaluating post-operative outcomes for this patient population. Methods: A total of 143 patients who underwent operative treated Mason Type III radial head fractures were analyzed retrospectively. PROMIS physical function (PF), PROMIS upper extremity (UE), PROMIS pain interference (PI), demographic variables, and range of motion were collected and analyzed over 12-month follow-up. Results: Radial head arthroplasty (RHA) was performed on 89 patients, open reduction and internal fixation (ORIF) was performed on 47 patients, and radial head excision was performed on 7 patients. Among the RHA patients, PROMIS PF, PI and UE demonstrated a change of -1.33 (p < 0.05), -1.48 (p < 0.05), and 2.23 (p < 0.05) respectively from injury to 12-months. Among the ORIF patients, PROMIS PF, PI and UE demonstrated a change of 3.22 (p < 0.05), -1.56 (p < 0.05), and 2.09 (p < 0.05) respectively from injury to 12-months. At the pre-operative and 12-month visits, the RHA group demonstrated lower PROMIS PF scores 34.75 vs 38.02 (p < 0.05) and 33.42 vs 41.24 (p < 0.05) respectively. Ther was no difference in PROMIS PI, UE, or elbow range of motion between the two groups at 6- or 12-month follow-up (p > 0.05). Conclusion: Comparing the RHA and ORIF groups, there was no difference in PROMIS PI or UE scores nor was there a clinically significant improvement at the 6- or 12-month mark. The ORIF group demonstrated improved PROMIS PF at all follow-up periods and did show a clinically significant improvement. Patient Acceptable Symptom State (PASS) correlated only with PROMIS UE at 6- and 12- months for both groups.

ChatGPT-4 accuracy for patient education in laryngopharyngeal reflux.

INTRODUCTION: Chatbot Generative Pre-trained Transformer (ChatGPT) is an artificial intelligence-powered language model chatbot able to help otolaryngologists in practice and research. The ability of ChatGPT in generating patient-centered information related to laryngopharyngeal reflux disease (LPRD) was evaluated. METHODS: Twenty-five questions dedicated to definition, clinical presentation, diagnosis, and treatment of LPRD were developed from the Dubai definition and management of LPRD consensus and recent reviews. Questions about the four aforementioned categories were entered into ChatGPT-4. Four board-certified laryngologists evaluated the accuracy of ChatGPT-4 with a 5-point Likert scale. Interrater reliability was evaluated. RESULTS: The mean scores (SD) of ChatGPT-4 answers for definition, clinical presentation, additional examination, and treatments were 4.13 (0.52), 4.50 (0.72), 3.75 (0.61), and 4.18 (0.47), respectively. Experts reported high interrater reliability for sub-scores (ICC = 0.973). The lowest performances of ChatGPT-4 were on answers about the most prevalent LPR signs, the most reliable objective tool for the diagnosis (hypopharyngeal-esophageal multichannel intraluminal impedance-pH monitoring (HEMII-pH)), and the criteria for the diagnosis of LPR using HEMII-pH. CONCLUSION: ChatGPT-4 may provide adequate information on the definition of LPR, differences compared to GERD (gastroesophageal reflux disease), and clinical presentation. Information provided upon extra-laryngeal manifestations and HEMII-pH may need further optimization. Regarding the recent trends identifying increasing patient use of internet sources for self-education, the findings of the present study may help draw attention to ChatGPT-4's accuracy on the topic of LPR.

RTF2 controls replication repriming and ribonucleotide excision at the replisome.

DNA replication through a challenging genomic landscape is coordinated by the replisome, which must adjust to local conditions to provide appropriate replication speed and respond to lesions that hinder its progression. We have previously shown that proteasome shuttle proteins, DNA Damage Inducible 1 and 2 (DDI1/2), regulate Replication Termination Factor 2 (RTF2) levels at stalled replisomes, allowing fork stabilization and restart. Here, we show that during unperturbed replication, RTF2 regulates replisome localization of RNase H2, a heterotrimeric enzyme that removes RNA from RNA-DNA heteroduplexes. RTF2, like RNase H2, is essential for mammalian development and maintains normal replication speed. However, persistent RTF2 and RNase H2 at stalled replication forks prevent efficient replication restart, which is dependent on PRIM1, the primase component of DNA polymerase α-primase. Our data show a fundamental need for RTF2-dependent regulation of replication-coupled ribonucleotide removal and reveal the existence of PRIM1-mediated direct replication restart in mammalian cells.

Adjunctive dorsal spanning plate fixation for challenging distal radius injuries.

Background: Distal radius fractures with severely osteoporotic bone or articular comminution can provide challenges to fixation with traditional volar locked plating alone. The purpose of this study was to evaluate the clinical, radiographic, and patient reported outcomes of patients undergoing distal radius fixation with volar locked plating and adjunctive dorsal bridge plating. Methods: We retrospectively identified 16 patients with distal radius fractures who underwent our preferred surgical technique for fixation. Patients underwent volar locked plate fixation as well as dorsal bridge fixation at time of surgery. Seven patients were indicated for severe articular comminution with volar rim fragmentation (44%), three patients were revised for nonunion after previous volar locked late fixation (19%), and six patients had severely osteoporotic bone with articular comminution (38%). Two patients (13%) sustained AO/OTA 23-A3 distal radius fracture, two patients (13%) had a 23-B3 fracture, two patients (13%) had a 23-C2 fracture and ten patients (63%) had a 23-C3 fracture. Results: The average patient age was 51.8 years ± 20.6. Patients were followed for an average of 12.2±6.3 months. The dorsal bridge plate was removed at an average of 11.1±2.4 weeks. The average post-operative radial inclination was 18.9±2.4°, radial height 12.4 mm ± 2.6 mm, and volar tilt 7.1±1.9°. There were no cases of deep or superficial infection. After dorsal bridge plate removal, patients demonstrated an average wrist extension of 55.3±9.5°, flexion 54.4±12.8°, radial deviation 15.7±3.2°, 25.2±3.9 degrees of ulnar deviation. Conclusion: Distal radius fractures in the setting of severely osteoporotic bone, salvage procedures, articular comminution, volar rim fractures, and revision surgery present uniquely difficult surgical challenges. Volar locked plating with adjunctive dorsal bridge plating can be used with good short- and long-term results.

Silk-Hyaluronic Acid for Vocal Fold Augmentation: Safety Profile and Long-Term Voice Outcomes.

OBJECTIVES: Silk-hyaluronic acid (silk-HA) is a novel vocal fold augmentation material used in humans since July 2020. We aim to describe indications, voice outcomes, and longevity data for silk-HA injectable when used for vocal fold injection (VFI) augmentation in a large cohort of patients with longer-term follow-up than preliminary clinical studies. METHODS: Retrospective chart review of Silk-HA injections for glottic insufficiency (GI) and follow-up between July 2020 and November 2023. Subject demographics, diagnoses, volume of material injected, VHI-10 data, time from injection, need for reinjection, and complications were collected. Blinded perceptual voice analysis of randomly selected pre- and post-intervention voice samples for unilateral vocal fold paralysis patients was performed by three voice-specialized speech-language pathologists, and changes in VHI-10 determined at various time intervals up to 1year and beyond. RESULTS: A total of 160 silk-HA injection procedures were performed: 59% female, with a mean age of 66± 13 (range 21-90) years. Ninety-four subjects had unilateral paralysis (58.4%); the remainder had scar, atrophy, paresis, or a combination thereof. Mean volume of silk-HA injected was 0.24± 0.14 cc. Major complications were rare, most notable for laryngoscopic evidence of hemilaryngeal edema (n = 6, 3.8%), with a readmission rate to hospital of 1.3% (n = 2). There was a statistically significant decrease in paired ΔVHI-10 and CAPE-V ratings for each of the postoperative follow-up intervals. A total of 24 (27.2%) repeat medialization procedures were recommended following silk-HA injection for unilateral paralysis. CONCLUSIONS: This study demonstrates that silk-HA is a safe product for VFI augmentation, and effective injectable for the treatment of GI due to unilateral vocal fold paralysis. Based on the current data, it is reasonable to counsel patients that they should expect benefit for several months following the injection. If patients reach 1year from their injection with a stable and satisfactory outcome, the majority experience ongoing benefit without need for additional procedures, however, the final duration of clinical effect appears to be years, but it is yet to be determined.

ATRX guards against aberrant differentiation in mesenchymal progenitor cells.

Alterations in the tumor suppressor ATRX are recurrently observed in mesenchymal neoplasms. ATRX has multiple epigenetic functions including heterochromatin formation and maintenance and regulation of transcription through modulation of chromatin accessibility. Here, we show in murine mesenchymal progenitor cells (MPCs) that Atrx deficiency aberrantly activated mesenchymal differentiation programs. This includes adipogenic pathways where ATRX loss induced expression of adipogenic transcription factors and enhanced adipogenic differentiation in response to differentiation stimuli. These changes are linked to loss of heterochromatin near mesenchymal lineage genes together with increased chromatin accessibility and gains of active chromatin marks. We additionally observed depletion of H3K9me3 at transposable elements, which are derepressed including near mesenchymal genes where they could serve as regulatory elements. Finally, we demonstrated that loss of ATRX in a mesenchymal malignancy, undifferentiated pleomorphic sarcoma, results in similar epigenetic disruption and de-repression of transposable elements. Together, our results reveal a role for ATRX in maintaining epigenetic states and transcriptional repression in mesenchymal progenitors and tumor cells and in preventing aberrant differentiation in the progenitor context.

No Differences in Clinical, Functional, or Patient-Reported Outcomes Following Trial of Nonoperative Management Before Open Reduction and Internal Fixation of Humeral Shaft Fractures.

OBJECTIVES: To test the hypothesis that primary osteosynthesis of humeral shaft fractures may lead to more favorable clinical, functional, and patient-reported outcomes than fixation following a trial of nonoperative management. DESIGN: Retrospective cohort review. SETTING: Academic level I trauma center. PATIENT SELECTION CRITERIA: Adult patients who presented with humeral shaft fractures and ultimately underwent open reduction and internal fixation (ORIF) from May 2011 to May 2021. Patients who underwent ORIF within 2 weeks of injury were grouped into the primary osteosynthesis cohort, and patients who underwent ORIF >4 weeks from the date of injury were grouped into the trial of nonoperative cohort. OUTCOME MEASURES AND COMPARISONS: Postoperative complications, elbow arc of motion, time to radiographic union, and patient-reported outcomes were investigated and compared between the primary osteosynthesis and trial of nonoperative management cohorts. RESULTS: One hundred twenty-seven patients fit the study criteria, 84 underwent primary osteosynthesis and 43 trialed initial nonoperative treatment. No differences were found in patient demographics between the primary osteosynthesis and trial of nonoperative management cohorts, including age (53 ± 19 vs. 57 ± 18; P = 0.25), sex (39% vs. 44% male, 61% vs. 56% female; P = 0.70), and Body Mass Index (BMI) (30 ± 6 vs. 32 ± 9; P = 0.38). The average time to operative intervention in the primary osteosynthesis group was 4 days (0-14 days) and 105 days (28-332 days) in the trial of nonoperative treatment group ( P < 0.01). No differences were found with regard to intraoperative blood loss, total operative time, time to radiographic union (determined using the Radiographic Union Scores for Humeral scoring system), or overall complication rates, including primary and secondary radial nerve injuries ( P = 0.23 and 0.86, respectively). Patients reported similar patient-reported outcomes measurement information system pain interference ( P = 0.73), depression (D) ( P = 0.99), and physical function ( P = 0.66) scores at their 6-month postsurgical follow-up visits. CONCLUSIONS: Patients who attempted a trial of nonoperative management for humeral shaft fractures before ORIF had similar clinical, functional, and patient-reported outcomes as those who underwent primary osteosynthesis. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Posterior tibial slope considered as an important addition to the CPAK classification system.

Introduction: Coronal Plane Alignment of the Knee (CPAK), is an informative way to classify native knee alignment types, but does not consider posterior tibial slope, an important variable in knee kinematics. We hypothesized that tibial slope would have a significant effect on knee kinematics and warrant consideration in addition to the CPAK system. Methods: We examined 335 adult patients with osteoarthritis receiving total knee arthroplasty. We measured the lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), and posterior tibial slope angle (PTS). Knees were categorized into CPAK classes and subdivided into types 'A' (PTS 8°) or 'B' (PTS >8°). We recorded pre-and-post operative knee flexion, and extension/flexion gaps in all subjects. Results: CPAK classes VII-IX were not seen. Classes I and II comprised a plurality of all knees. One-third of all knees were type B. CPAK classes III, IV, and VI had greater type B proportions, but this was not statistically significant. Type B knees had greater flexion both pre-op (p < .001) and post-op (p = .043); type A knees had greater flexion improvement pre-to-post operatively (p = .045). Type A knees had greater medial and lateral flexion-extension gap change pre-operatively (p = .021) and (p = .027), respectively. Type B knees had greater medial-lateral gap imbalance preoperatively in both flexion and extension. Discussion/conclusion: Our results suggest that there are important pre and post-operative differences in medial and lateral femorotibial gap balance between type A and B knees that require consideration for intra-operative balancing. Differences in knee flexion further solidify that PTS is an important variable that affects kinematics before and after TKA. We propose the addition of PTS types A and B to the existing CPAK classes. This is an easy and logical way to create a comprehensive classification system in both coronal and sagittal planes that captures further differences in knee kinematics.

Predicting Acute Median Neuropathy in Perilunate Injuries.

Purpose: Perilunate fracture dislocation (PLFD) injuries are associated with the development of acute carpal tunnel syndrome (CTS). The purpose of our study was to identify the factors that increase the likelihood of developing CTS in patients with PLFD. Additionally, we attempted to classify patients who did not initially undergo carpal tunnel release (CTR) at the time of injury but eventually underwent CTR within the follow-up period. Methods: Patients presenting to a level-1 trauma center with isolated PLFDs (Mayfield III-IV) were retrospectively identified by using CPT and ICD-10 codes. Polytraumatized patients, those with a history of previous wrist trauma, or those with previous carpal tunnel symptoms or surgery were excluded. Outcomes of interest included the development of acute CTS, pre- and post-reduction changes in CTS symptoms, and associated hand and wrist fractures. Chi-square tests, Kruskal-Wallis tests, and multivariate logistic regression were used to examine the predictors of developing CTS after a PLFD. Results: In total, 43 patients were included in the final cohort, with a mean age of 44 years, of which 77% were men. The most common fracture of the carpus included scaphoid fractures (9/43, 21%). The average time from presentation to reduction was 636 minutes. Acute CTS symptoms before reduction were present in 26% of the patients and increased post-reduction to 28%. No difference exists between the time to sedation and the presence of acute carpal tunnel symptoms (P >.05). During initial surgical intervention, 79% underwent CTR (27/34). Of the seven patients who did not initially undergo a CTR, 57% (4/7) required a CTR within the follow-up period. Conclusion: Reduction of PLFDs did not significantly improve the number of patients with acute CTS. More than 50% of the patients who did not undergo a CTR at the initial surgery required a CTR within the follow-up period. Type of study/level of evidence: Prognostic III.