Modelling the impact of wastewater flows and management practices on antimicrobial resistance in dairy farms.

Dairy slurry is a major source of environmental contamination with antimicrobial resistant genes and bacteria. We developed mathematical models and conducted on-farm research to explore the impact of wastewater flows and management practices on antimicrobial resistance (AMR) in slurry. Temporal fluctuations in cephalosporin-resistant Escherichia coli were observed and attributed to farm activities, specifically the disposal of spent copper and zinc footbath into the slurry system. Our model revealed that resistance should be more frequently observed with relevant determinants encoded chromosomally rather than on plasmids, which was supported by reanalysis of sequenced genomes from the farm. Additionally, lower resistance levels were predicted in conditions with lower growth and higher death rates. The use of muck heap effluent for washing dirty channels did not explain the fluctuations in cephalosporin resistance. These results highlight farm-specific opportunities to reduce AMR pollution, beyond antibiotic use reduction, including careful disposal or recycling of waste antimicrobial metals.

Role of myeloid cells in ischemic retinopathies: recent advances and unanswered questions.

Myeloid cells including microglia and macrophages play crucial roles in retinal homeostasis by clearing cellular debris and regulating inflammation. These cells are activated in several blinding ischemic retinal diseases including diabetic retinopathy, where they may exert both beneficial and detrimental effects on neurovascular function and angiogenesis. Myeloid cells impact the progression of retinal pathologies and recent studies suggest that targeting myeloid cells is a promising therapeutic strategy to mitigate diabetic retinopathy and other ischemic retinal diseases. This review summarizes the recent advances in our understanding of the role of microglia and macrophages in retinal diseases and focuses on the effects of myeloid cells on neurovascular injury and angiogenesis in ischemic retinopathies. We highlight gaps in knowledge and advocate for a more detailed understanding of the role of myeloid cells in retinal ischemic injury to fully unlock the potential of targeting myeloid cells as a therapeutic strategy for retinal ischemia.

The role of imaging in extremity sarcoma surgery.

The surgical management of extremity bone and soft tissue sarcomas has evolved significantly over the last 50 years. The introduction and refinement of high-resolution cross-sectional imaging has allowed accurate assessment of anatomy and tumor extent, and in the current era more than 90% of patients can successfully undergo limb-salvage surgery. Advances in imaging have also revolutionized the clinician's ability to assess treatment response, detect metastatic disease, and perform intraoperative surgical navigation. This review summarizes the broad and essential role radiology plays in caring for sarcoma patients from diagnosis to post-treatment surveillance. Present evidence-based imaging paradigms are highlighted along with key future directions.

Life Expectancy After Treatment of Metastatic Bone Disease: An International Trend Analysis.

INTRODUCTION: The decision to treat metastatic bone disease (MBD) surgically depends in part on patient life expectancy. We are unaware of an international analysis of how life expectancy among these patients has changed over time. Therefore, we asked (1) how has the life expectancy for patients treated for MBD changed over time, and (2) which, if any, of the common primary cancer types are associated with longer survival after treatment of MBD? METHODS: We reviewed data collected from 2000 to 2022 in an international MBD database, as well as data used for survival model validation. We included 3,353 adults who underwent surgery and/or radiation. No patients were excluded. Patients were grouped by treatment date into period 1 (2000 to 2009), period 2 (2010 to 2019), and period 3 (2020 to 2022). Cumulative survival was portrayed using Kaplan-Meier curves; log-rank tests were used to determine significance at P < 0.05. Subgroup analyses by primary cancer diagnosis were performed. RESULTS: Median survival in period 2 was longer than in period 1 ( P < 0.001). Median survival (at which point 50% of patients survived) had not been reached for period 3. Median survival was longer in period 2 for all cancer types ( P < 0.001) except thyroid. Only lung cancer reached median survival in period 3, which was longer compared with periods 1 and 2 ( P < 0.001). Slow-growth, moderate-growth, and rapid-growth tumors all demonstrated longer median survival from period 1 to period 2; only rapid-growth tumors reached median survival for period 3, which was longer compared with periods 1 and 2 ( P < 0.001). DISCUSSION: Median duration of survival after treatment of MBD has increased, which was a consistent finding in nearly all cancer types. Longer survival is likely attributable to improvements in both medical and surgical treatments. As life expectancy for patients with MBD increases, surgical methods should be selected with this in mind. LEVEL OF EVIDENCE: VI.

Symptomatic Neuroma Development following En Bloc Resection of Skeletal and Soft-Tissue Tumors: A Retrospective Analysis of 331 Cases.

BACKGROUND: Although symptomatic neuroma formation has been described in other patient populations, these data have not been studied in patients undergoing resection of musculoskeletal tumors. This study aimed to characterize the incidence and risk factors of symptomatic neuroma formation following en bloc resection in this population. METHODS: The authors retrospectively reviewed adults undergoing en bloc resections for musculoskeletal tumors at a high-volume sarcoma center from 2014 to 2019. The authors included en bloc resections for an oncologic indication and excluded non-en bloc resections, primary amputations, and patients with insufficient follow-up. Data are provided as descriptive statistics, and multivariable regression modeling was performed. RESULTS: The authors included 231 patients undergoing 331 en bloc resections (female, 46%; mean age, 52 years). Nerve transection was documented in 87 resections (26%). There were 81 symptomatic neuromas (25%) meeting criteria of Tinel sign or pain on examination and neuropathy in the distribution of suspected nerve injury. Factors associated with symptomatic neuroma formation included age 18 to 39 [adjusted OR (aOR), 3.6; 95% CI, 1.5 to 8.4; P < 0.01] and 40 to 64 (aOR, 2.2; 95% CI, 1.1 to 4.6; P = 0.04), multiple resections (aOR, 3.2; 95% CI, 1.7 to 5.9; P < 0.001), preoperative neuromodulator requirement (aOR, 2.7; 95% CI, 1.2 to 6.0; P = 0.01), and resection of fascia or muscle (aOR, 0.5; 95% CI, 0.3 to 1.0; P = 0.045). CONCLUSION: The authors' results highlight the importance of adequate preoperative optimization of pain control and intraoperative prophylaxis for neuroma prevention following en bloc resection of tumors, particularly for younger patients with a recurrent tumor burden. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

The use of weakly supervised machine learning for necrosis assessment in patients with osteosarcoma: A pilot study.

Percent necrosis (PN) following chemotherapy is a prognostic factor for survival in osteosarcoma. Pathologists estimate PN by calculating tumor viability over an average of whole-slide images (WSIs). This non-standardized, labor-intensive process requires specialized training and has high interobserver variability. Therefore, we aimed to develop a machine-learning model capable of calculating PN in osteosarcoma with similar accuracy to that of a musculoskeletal pathologist. In this proof-of-concept study, we retrospectively obtained six WSIs from two patients with conventional osteosarcomas. A weakly supervised learning model was trained by using coarse and incomplete annotations of viable tumor, necrotic tumor, and nontumor tissue in WSIs. Weakly supervised learning refers to processes capable of creating predictive models on the basis of partially and imprecisely annotated data. Once "trained," the model segmented areas of tissue and determined PN of the same six WSIs. To assess model fidelity, the pathologist also estimated PN of each WSI, and we compared the estimates using Pearson's correlation and mean absolute error (MAE). MAE was 15% over the six samples, and 6.4% when an outlier was removed, for which the model inaccurately labeled cartilaginous tissue. The model and pathologist estimates were strongly, positively correlated (r = 0.85). Thus, we created and trained a weakly supervised machine learning model to segment viable tumor, necrotic tumor, and nontumor and to calculate PN with accuracy similar to that of a musculoskeletal pathologist. We expect improvement can be achieved by annotating cartilaginous and other mesenchymal tissue for better representation of the histological heterogeneity in osteosarcoma.

Predicting Risk of 30-day Postoperative Morbidity Using the Pathologic Fracture Mortality Index.

INTRODUCTION: The purpose of this study was to evaluate the ability of the Pathologic Fracture Mortality Index (PFMI) to predict the risk of 30-day morbidity after pathologic fracture fixation and compare its efficacy with those of the American Society of Anesthesiologists (ASA) physical status, modified Charlson Comorbidity Index (mCCI), and modified frailty index (mFI-5). METHODS: Cohorts of 1,723 patients in the American College of Surgeons National Surgical Quality Improvement Program database from 2005 to 2020 and 159 patients from a tertiary cancer referral center who underwent fixation for impending or completed pathologic fractures of long bones were retrospectively analyzed. National Surgical Quality Improvement Program morbidity variables were categorized into medical, surgical, utilization, and all-cause. PFMI, ASA, mCCI, and mFI-5 scores were calculated for each patient. Area under the curve (AUC) was used to compare efficacies. RESULTS: AUCs predicting all-cause morbidity were 0.62, 0.54, and 0.56 for the PFMI, ASA, and mFI-5, respectively. The PFMI outperformed the ASA and mFI-5 in predicting all-cause ( P < 0.01), medical ( P = 0.01), and utilization ( P < 0.01) morbidities. In the 2005 to 2012 subset, the PFMI outperformed the ASA, mFI-5, and mCCI in predicting all-cause ( P = 0.01), medical ( P = 0.03), and surgical ( P = 0.05) morbidities but performed similarly to utilization morbidity ( P = 0.19). In our institutional cohort, the AUC for the PFMI in morbidity stratification was 0.68. The PFMI was associated with all-cause (odds ratio [OR], 1.30; 95% confidence interval [CI], 1.12 to 1.51; P < 0.001), medical (OR, 1.19; 95% CI, 1.03 to 1.40; P = 0.046), and utilization (OR, 1.32; 95% CI, 1.14 to 1.52; P < 0.001) morbidities but not significantly associated with surgical morbidity (OR, 1.21; 95% CI, 0.98 to 1.49; P = 0.08) in this cohort. DISCUSSION: The PFMI is an advancement in postoperative morbidity risk stratification of patients with pathologic fracture from metastatic disease. LEVEL OF EVIDENCE: III.

The efficacy and safety of direct oral anticoagulants compared with low-molecular-weight heparin for venous thromboembolism prophylaxis after surgical resection of primary lower extremity bone or soft-tissue sarcoma.

INTRODUCTION: The incidence of postoperative venous thromboembolism (VTE) and wound complications is greater after sarcoma resection. We sought to identify differences in postoperative VTE and bleeding complications with direct oral anticoagulants (DOACs) versus low-molecular-weight heparin (LMWH) following resection of lower extremity primary bone or soft tissue sarcoma. METHODS: We retrospectively identified 2083 patients from the PearlDiver database who underwent resection of primary bone or soft tissue sarcoma of the lower extremity from January 2010 to October 2021 and prescribed LMWH or DOAC within 90-days postoperatively. The primary outcomes were comparison of postoperative incidence and odds of deep venous thrombosis (DVT), pulmonary embolism (PE), and bleeding complications within 90-days following resection. RESULTS: Patients prescribed DOACs had a greater odds of DVT (odds ratio [OR]: 1.60; 95% confidence interval [CI]: 1.06-2.41; p = 0.024) and PE (OR: 3.38; 95% CI: 1.96-5.86; p < 0.001) within 90-days following resection of bone sarcoma when compared with the LMWH cohort. Patients undergoing resection of soft tissue sarcomas also had greater odds DVT (OR: 1.65; 95% CI: 1.09-2.49; p = 0.016) and PE (OR: 2.62; 95% CI: 1.52-4.54; p < 0.001) in the DOAC cohort. There was no difference in the odds of bleeding complications. CONCLUSION: This study demonstrated an increased incidence and odds of VTE, but not bleeding complications, when using DOACs versus LMWH after primary bone or soft tissue sarcoma resection. LEVEL OF EVIDENCE: Level III.

Team Approach: Extremity Soft Tissue Sarcoma.

¼ Synovial sarcoma is a soft tissue sarcoma that most commonly presents in the extremity in a periarticular location.¼ As the history and physical examination of patients with synovial sarcoma can overlap considerably with those of patients with non-oncologic orthopedic conditions, it is important that orthopedic surgeons maintain a high level of suspicion when caring for patients with extremity masses.¼ Soft tissue sarcomas are best treated using a team approach. Early recognition and referral to a multidisciplinary sarcoma team are crucial to ensure the best clinical outcome for the patient.

The arginase 1/ornithine decarboxylase pathway suppresses HDAC3 to ameliorate the myeloid cell inflammatory response: implications for retinal ischemic injury.

The enzyme arginase 1 (A1) hydrolyzes the amino acid arginine to form L-ornithine and urea. Ornithine is further converted to polyamines by the ornithine decarboxylase (ODC) enzyme. We previously reported that deletion of myeloid A1 in mice exacerbates retinal damage after ischemia/reperfusion (IR) injury. Furthermore, treatment with A1 protects against retinal IR injury in wild-type mice. PEG-A1 also mitigates the exaggerated inflammatory response of A1 knockout (KO) macrophages in vitro. Here, we sought to identify the anti-inflammatory pathway that confers macrophage A1-mediated protection against retinal IR injury. Acute elevation of intraocular pressure was used to induce retinal IR injury in mice. A multiplex cytokine assay revealed a marked increase in the inflammatory cytokines interleukin 1ß (IL-1ß) and tumor necrosis factor α (TNF-α) in the retina at day 5 after IR injury. In vitro, blocking the A1/ODC pathway augmented IL-1ß and TNF-α production in stimulated macrophages. Furthermore, A1 treatment attenuated the stimulated macrophage metabolic switch to a pro-inflammatory glycolytic phenotype, whereas A1 deletion had the opposite effect. Screening for histone deacetylases (HDACs) which play a role in macrophage inflammatory response showed that A1 deletion or ODC inhibition increased the expression of HDAC3. We further showed the involvement of HDAC3 in the upregulation of TNF-α but not IL-1ß in stimulated macrophages deficient in the A1/ODC pathway. Investigating HDAC3 KO macrophages showed a reduced inflammatory response and a less glycolytic phenotype upon stimulation. In vivo, HDAC3 co-localized with microglia/macrophages at day 2 after IR in WT retinas and was further increased in A1-deficient retinas. Collectively, our data provide initial evidence that A1 exerts its anti-inflammatory effect in macrophages via ODC-mediated suppression of HDAC3 and IL-1ß. Collectively we propose that interventions that augment the A1/ODC pathway and inhibit HDAC3 may confer therapeutic benefits for the treatment of retinal ischemic diseases.

Functional outcomes after open reconstruction or nonoperative management of 81 pathologic acetabular fractures from metastatic bone disease.

Background: Pathologic acetabular fracture secondary to skeletal metastasis may result in debilitating pain, inability to ambulate, and impaired quality of life, which may mark the first period of dependent care in cancer patients. Acetabular reconstruction may involve morbid procedures with increased complication rates. This study aimed to evaluate the evolution of pain, performance status, and ambulation following nonoperative management or open reconstruction of pathologic acetabular fractures. Methods: A retrospective cohort of 2630 adult patients with osseous metastatic disease treated at a high-volume cancer center between 2005 and 2021 was screened for pathologic fractures of the acetabulum. The study outcomes were pain, performance status, and the ability to ambulate. We identified 78 patients (median age, 60 years; 37 female patients [46%]) with 81 fractures. Of these, treatment consisted of open reconstruction (n = 34) or nonoperative management alone (n = 47). The mean follow-up in surviving patients was 3.4 years. Results: Open reconstruction was performed more frequently for displaced fractures (P < 0.01), Harrington class III or IV acetabula (P < 0.01), and patients with a performance status ≥3 at hospitalization (P = 0.00). Open reconstruction was associated with clinically meaningful improvements in pain (adjusted odds ratio [aOR], 8.3; 95% CI, 1.4-50.6; P = 0.02) and performance status (aOR, 10.9; 95% CI, 1.7-71.0; P = 0.01) at discharge and a restoration of ambulation (aOR, 7.5; 95% CI, 1.9-29.8; P < 0.01) at final follow-up. Conclusions: In patients with pathologic acetabular fracture due to osseous metastatic disease, functional improvements in pain, performance status, and ambulation were observed following open acetabular reconstruction in carefully selected patients, with no impact on survival, while noninferior improvements were observed in patients receiving nonoperative management when considering their larger clinical context. Level of evidence: Level III, therapeutic study.

Recurrent chondromyxoid fibroma of the distal femur treated with percutaneous cryoablation.

Chondromyxoid fibroma is a rare, benign tumor of the bone with excellent prognosis but a high rate of recurrence. We report a patient presenting with pain and a history of chondromyxoid fibroma of the distal left femur previously treated with multiple prior curettage and bone graft procedures. Magnetic resonance imaging and histopathology indicated a recurrence of tumor. Due to the small size of the tumor recurrence and challenges associated with prior open surgery, the patient underwent cryoablation of the lesion with computed tomography guidance. Follow-up 18 months later indicated a resolution of pain and improvement on magnetic resonance imaging, and no concerns after 20 months. To our knowledge, this is the first reported case of chondromyxoid fibroma treated with cryoablation. This case suggests cryoablation could be considered in the setting of recurrent chondromyxoid fibroma for local tumor control.

Multi-color Flow Cytometry Protocol to Characterize Myeloid Cells in Mouse Retina Research.

Myeloid cells, specifically microglia and macrophages, are activated in retinal diseases and can improve or worsen retinopathy outcomes based on their inflammatory phenotype. However, assessing the myeloid cell response after retinal injury in mice remains challenging due to the small tissue size and the challenges of distinguishing microglia from infiltrating macrophages. In this protocol paper, we describe a flow cytometry-based protocol to assess retinal microglia/macrophage and their inflammatory phenotype after injury. The protocol is amenable to the incorporation of other markers of interest to other researchers. Key features This protocol describes a flow cytometry-based method to analyze the myeloid cell response in retinopathy mouse models. The protocol can distinguish between microglia- and monocyte-derived macrophages. It can be modified to incorporate markers of interest. We show representative results from three different retinopathy models, namely ischemia-reperfusion injury, endotoxin-induced uveitis, and oxygen-induced retinopathy.

Metastatic sarcomatoid carcinoma to bone.

BACKGROUND AND OBJECTIVES: Distinguishing sarcomatoid carcinoma from primary sarcoma is clinically important. We sought to characterize metastatic sarcomatoid bone disease and its management. METHODS: We analyzed the characteristics of all cases of sarcomatoid carcinoma to bone at a single institution from 2001 to 2021, excluding patients with nonosseous metastases. Survival was evaluated using the Kaplan-Meier method. RESULTS: We identified 15 cases of metastatic sarcomatoid carcinoma to bone. In seven cases the primary cancer was unknown at presentation. Renal cell carcinoma was suspected or confirmed in nine cases. Nine patients presented with pathologic fracture and two with concomitant visceral metastases. All patients underwent image-guided core needle or open biopsy. Ten required surgery for discrete osseous metastases; in four cases definitive surgery was delayed (median delay, 19 days) due to inability to rule out sarcoma with frozen section. No patients required reoperation or had construct failure. Thirteen died of disease; median survival was 17.5 months (interquartile range, 6.2-25.1). CONCLUSIONS: Metastatic sarcomatoid carcinoma is a clinically challenging entity. Multidisciplinary input and communication are key to identifying the primary carcinoma, locating osseous metastases, and defining an operative fixation that will survive the remainder of the patient's life.

Incidence of and Risk Factors for Thromboembolism After Endoprosthetic Reconstruction in Musculoskeletal Oncology Patients.

BACKGROUND: The aim of the present study was to assess the incidence of and risk factors for thromboembolic events-including assessment of the intraoperative use of tranexamic acid and postoperative use of chemical thromboprophylaxis-in patients undergoing operative treatment of primary bone or soft-tissue sarcoma or oligometastatic bone disease. METHODS: This study was performed as a secondary analysis of prospective data collected from the Prophylactic Antibiotic Regimens in Tumor Surgery (PARITY) randomized controlled trial, which included 604 patients ≥12 years old who underwent surgical resection and endoprosthetic reconstruction for either primary bone or soft-tissue sarcoma or oligometastatic disease of the femur or tibia. We determined the incidence of thromboembolic events in these patients and evaluated potential risk factors, including patient age, sex, antibiotic treatment group, type of tumor (i.e., primary bone or soft-tissue sarcoma or metastatic bone disease), intraoperative tranexamic acid, tourniquet use, operative time, pathologic characteristics (i.e., American Joint Committee on Cancer grade, vascular invasion, and percent necrosis), postoperative chemical thromboprophylaxis regimen, and surgical site infection. Continuous variables were assessed with use of the Student t test. Categorical variables were assessed with use of the Pearson chi-square test, except when the expected cell counts were <5, in which case the Fisher exact test was utilized. Significance was set at 0.05. RESULTS: Postoperative thromboembolic events occurred in 11 (1.8%) of 604 patients. Patients who experienced a thromboembolic event had a significantly higher mean (± standard deviation) age (59.6 ± 17.5 years) than those who did not experience a thromboembolic event (40.9 ± 21.8; p = 0.002). Patients randomized to the long-term antibiotic group had a significantly higher incidence of thromboembolic events (9 of 293; 3.1%) than those randomized to the short-term antibiotic group (2 of 311; 0.64%; p = 0.03). Neither intraoperative tranexamic acid nor postoperative chemical thromboprophylaxis were significantly associated with the occurrence of a thromboembolic event. CONCLUSIONS: Although relatively rare in the PARITY cohort, thromboembolic events were more likely to occur in older patients and those receiving long-term prophylactic antibiotics. Intraoperative tranexamic acid and postoperative chemical thromboprophylaxis were not associated with a greater incidence of thromboembolic events. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Does the Use of Negative Pressure Wound Therapy and Postoperative Drains Impact the Development of Surgical Site Infections?: A PARITY Trial Secondary Analysis.

BACKGROUND: Surgical site infections (SSIs) represent a major complication following oncologic reconstructions. Our objectives were (1) to assess whether the use of postoperative drains and/or negative pressure wound therapy (NPWT) were associated with SSIs following lower-extremity oncologic reconstruction and (2) to identify factors associated with the duration of postoperative drains and with the duration of NPWT. METHODS: This is a secondary analysis of the Prophylactic Antibiotic Regimens in Tumor Surgery (PARITY) trial, a multi-institution randomized controlled trial of lower-extremity oncologic reconstructions. Data were recorded regarding the use of drains alone, NPWT alone, or both NPWT and drains, including the total duration of each postoperatively. We analyzed postoperative drain duration and associations with tourniquet use, intraoperative thromboprophylaxis or antifibrinolytic use, incision length, resection length, and total operative time, through use of a linear regression model. A Cox proportional hazards model was used to evaluate the independent predictors of SSI. RESULTS: Overall, 604 patients were included and the incidence of SSI was 15.9%. Postoperative drains alone were used in 409 patients (67.7%), NPWT alone was used in 15 patients (2.5%), and both postoperative drains and NPWT were used in 68 patients (11.3%). The median (and interquartile range [IQR]) duration of drains and of NPWT was 3 days (IQR, 2 to 5 days) and 6 days (IQR, 4 to 8 days), respectively. The use of postoperative drains alone, NPWT alone, or both drains and NPWT was not associated with SSI (p = 0.14). Increased postoperative drain duration was associated with longer operative times and no intraoperative tourniquet use, as shown on linear regression analysis (p < 0.001 and p = 0.03, respectively). A postoperative drain duration of ≥14 days (hazard ratio [HR], 3.6; 95% confidence interval [CI], 1.3 to 9.6; p = 0.01) and an operative time of ≥8 hours (HR, 4.5; 95% CI, 1.7 to 11.9; p = 0.002) were independent predictors of SSI following lower-extremity oncologic reconstruction. CONCLUSIONS: A postoperative drain duration of ≥14 days and an operative time of ≥8 hours were independent predictors of SSI following lower-extremity oncologic reconstruction. Neither the use of postoperative drains nor the use of NPWT was a predictor of SSI. Future research is required to delineate the association of the combined use of postoperative drains and NPWT with SSI. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Complex/cryptic EWSR1::FLI1/ERG Gene Fusions and 1q Jumping Translocation in Pediatric Ewing Sarcomas.

Ewing sarcomas (ES) are rare small round cell sarcomas often affecting children and characterized by gene fusions involving one member of the FET family of genes (usually EWSR1) and a member of the ETS family of transcription factors (usually FLI1 or ERG). The detection of EWSR1 rearrangements has important diagnostic value. Here, we conducted a retrospective review of 218 consecutive pediatric ES at diagnosis and found eight patients having data from chromosome analysis, FISH/microarray, and gene-fusion assay. Three of these eight ES had novel complex/cryptic EWSR1 rearrangements/fusions by chromosome analysis. One case had a t(9;11;22)(q22;q24;q12) three-way translocation involving EWSR1::FLI1 fusion and 1q jumping translocation. Two cases had cryptic EWSR1 rearrangements/fusions, including one case with a cryptic t(4;11;22)(q35;q24;q12) three-way translocation involving EWSR1::FLI1 fusion, and the other had a cryptic EWSR1::ERG rearrangement/fusion on an abnormal chromosome 22. All patients in this study had various aneuploidies with a gain of chromosome 8 (75%), the most common, followed by a gain of chromosomes 20 (50%) and 4 (37.5%), respectively. Recognition of complex and/or cryptic EWSR1 gene rearrangements/fusions and other chromosome abnormalities (such as jumping translocation and aneuploidies) using a combination of various genetic methods is important for accurate diagnosis, prognosis, and treatment outcomes of pediatric ES.

TIAM1 acts as an actin organization regulator to control adipose tissue-derived pericyte cell fate.

Pericytes are multipotent mesenchymal precursor cells that demonstrate tissue-specific properties. In this study, by comparing human adipose tissue- and periosteum-derived pericyte microarrays, we identified T cell lymphoma invasion and metastasis 1 (TIAM1) as a key regulator of cell morphology and differentiation decisions. TIAM1 represented a tissue-specific determinant between predispositions for adipocytic versus osteoblastic differentiation in human adipose tissue-derived pericytes. TIAM1 overexpression promoted an adipogenic phenotype, whereas its downregulation amplified osteogenic differentiation. These results were replicated in vivo, in which TIAM1 misexpression altered bone or adipose tissue generation in an intramuscular xenograft animal model. Changes in pericyte differentiation potential induced by TIAM1 misexpression correlated with actin organization and altered cytoskeletal morphology. Small molecule inhibitors of either small GTPase Rac1 or RhoA/ROCK signaling reversed TIAM1-induced morphology and differentiation in pericytes. In summary, our results demonstrate that TIAM1 regulates the cellular morphology and differentiation potential of human pericytes, representing a molecular switch between osteogenic and adipogenic cell fates.

Professional Society Opportunities and Involvement for Early-Career Orthopaedic Surgeons.

Professional societies can provide orthopaedic surgeons opportunities to build strong fellowship among colleagues within a specialty, to gain leadership positions and responsibilities, and to contribute to the latest research and practice management guidelines. However, early-career surgeons often receive little to no guidance about how membership can benefit them in the long term. The primary purpose of this review article was to provide an overview of orthopaedic professional societies, why early-career orthopaedic surgeons should consider membership, and how they can get involved. Topics discussed in this article include the missions of various societies, value in career advancement both in academic and private practice settings, benefits to patient care, and tips for budding surgeons on how to rise up the ranks within a given professional society. We also provide a comprehensive list of leadership development, fellowship, mentorship, and research opportunities that are designed for orthopaedic surgeons within their first 10 years of practice.

CNTNAP4 signaling regulates osteosarcoma disease progression.

Improved treatment strategies for sarcoma rely on clarification of the molecular mediators of disease progression. Recently, we reported that the secreted glycoprotein NELL-1 modulates osteosarcoma (OS) disease progression in part via altering the sarcomatous extracellular matrix (ECM) and cell-ECM interactions. Of known NELL-1 interactor proteins, Contactin-associated protein-like 4 (Cntnap4) encodes a member of the neurexin superfamily of transmembrane molecules best known for its presynaptic functions in the central nervous system. Here, CRISPR/Cas9 gene deletion of CNTNAP4 reduced OS tumor growth, sarcoma-associated angiogenesis, and pulmonary metastases. CNTNAP4 knockout (KO) in OS tumor cells largely phenocopied the effects of NELL-1 KO, including reductions in sarcoma cell attachment, migration, and invasion. Further, CNTNAP4 KO cells were found to be unresponsive to the effects of NELL-1 treatment. Transcriptomic analysis combined with protein phospho-array demonstrated notable reductions in the MAPK/ERK signaling cascade with CNTNAP4 deletion, and the ERK1/2 agonist isoproterenol restored cell functions among CNTNAP4 KO tumor cells. Finally, human primary cells and tissues in combination with sequencing datasets confirmed the significance of CNTNAP4 signaling in human sarcomas. In summary, our findings demonstrate the biological importance of NELL-1/CNTNAP4 signaling axis in disease progression of human sarcomas and suggest that targeting the NELL-1/CNTNAP4 signaling pathway represents a strategy with potential therapeutic benefit in sarcoma patients.