Evaluation of obesity and age as a predictive factor of lower extremity compartment syndrome: A national trauma data bank analysis.

BACKGROUND: Risk factors of acute compartment syndrome (ACS) of the leg include tibial fractures followed by soft tissue injuries. METHODS: Data collected from the National Trauma Data Bank (NTDB) between 2017 and 2019 were analyzed for adult patients with lower extremity fractures, including proximal tibia, tibial shaft, and distal tibia. The primary outcome was a diagnosis of ACS. RESULTS: There were 1052/220,868 patients with lower extremity fractures with a concomitant diagnosis of compartment syndrome. Our study has shown that patients with a BMI of ≥30 had a lower incidence of compartment syndrome when compared with patients with a BMI of 25-29 and controlled for fracture type. Increased age ≥55 in males, and females between 65 and 84, also demonstrated a decreased risk. Proximal tibial fractures (n â€‹= â€‹54,696) were significantly associated with ACS compared to midshaft (n â€‹= â€‹42,153) and distal (n â€‹= â€‹100,432), p â€‹< â€‹0.0001. CONCLUSION: We found that being overweight decreases risk for development of compartment syndrome in patients with lower extremity fractures. This big data study aids in establishing risk factors for development of ACS in adult trauma patients.

Characterizing Trauma Patients with Delays in Orthopaedic Process Measures.

INTRODUCTION: Early operative intervention in orthopaedic injuries is associated with decreased morbidity and mortality. Relevant process measures (e.g. femoral shaft fixation <24 hours) are used in trauma quality improvement programs to evaluate performance. Currently, there is no mechanism to account for patients who are unable to undergo surgical intervention (i.e. physiologically unstable). We characterized the factors associated with patients who did not meet these orthopaedic process measures. METHODS: A retrospective cohort study of patients from 35 ACS-COT verified Level 1 and Level 2 trauma centers was performed utilizing quality collaborative data (2017-2022). Inclusion criteria were adult patients (≥18 years), ISS ≥5, and a closed femoral shaft or open tibial shaft fracture classified via the Abbreviated Injury Scale version 2005 (AIS2005). Relevant factors (e.g. physiologic) associated with a procedural delay >24 hours were identified through a multivariable logistic regression and the effect of delay on inpatient outcomes was assessed. A sub-analysis characterized the rate of delay in "healthy patients". RESULTS: We identified 5,199 patients with a femoral shaft fracture and 87.5% had a fixation procedure, of which 31.8% had a delay, and 47.1% of those delayed were "healthy." There were 1,291 patients with an open tibial shaft fracture, 92.2% had fixation, 50.5% had an irrigation and debridement and 11.2% and 18.7% were delayed, respectively. High ISS, older age and multiple medical comorbidities were associated with a delay in femur fixation, and those delayed had a higher incidence of complications. CONCLUSIONS: There is a substantial incidence of surgical delays in some orthopaedic trauma process measures that are predicted by certain patient characteristics, and this is associated with an increased rate of complications. Understanding these factors associated with a surgical delay, and effectively accounting for them, is key if these process measures are to be used appropriately in quality improvement programs. LEVEL OF EVIDENCE: Level III; Therapeutic/Care Management.

Lumbopelvic fixation in the treatment of spinopelvic dissociation: union, complications, and neurologic outcomes of a multicenter case series.

PURPOSE: To review outcomes of spinopelvic dissociation treated with open lumbopelvic fixation. METHODS: We reviewed all cases of spinopelvic dissociation treated at three Level-I trauma centers with open lumbopelvic fixation, including those with adjunctive percutaneous fixation. We collected demographic data, associated injuries, pre- and postoperative neurologic status, pre- and postoperative kyphosis, and Roy-Camille classification. Outcomes included presence of union, reoperation rates, and complications involving hardware or wound. RESULTS: From an initial cohort of 260 patients with spinopelvic dissociation, forty patients fulfilled inclusion criteria with a median follow-up of 351 days. Ten patients (25%) had a combination of percutaneous iliosacral and open lumbopelvic repair. Average pre- and postoperative kyphosis was 30 degrees and 26 degrees, respectively. Twenty patients (50%) had neurologic deficit preoperatively, and eight (20%) were unknown or unable to be assessed. All patients presenting with bowel or bladder dysfunction (n = 12) underwent laminectomy at time of surgery, with 3 patients (25%) having continued dysfunction at final follow-up. Surgical site infection occurred in four cases (10%) and wound complications in two (5%). All cases (100%) went on to union and five patients (13%) required hardware removal. CONCLUSION: Open lumbopelvic fixation resulted in a high union rate in the treatment of spinopelvic dissociation. Approximately 1 in 6 patients had a wound complication, the majority of which were surgical site infections. Bowel and bladder dysfunction at presentation were common with the majority of cases resolving by final follow-up when spinopelvic dissociation had been treated with decompression and stable fixation.

The bone ecosystem facilitates multiple myeloma relapse and the evolution of heterogeneous drug resistant disease.

Multiple myeloma (MM) is an osteolytic malignancy that is incurable due to the emergence of treatment resistant disease. Defining how, when and where myeloma cell intrinsic and extrinsic bone microenvironmental mechanisms cause relapse is challenging with current biological approaches. Here, we report a biology-driven spatiotemporal hybrid agent-based model of the MM-bone microenvironment. Results indicate MM intrinsic mechanisms drive the evolution of treatment resistant disease but that the protective effects of bone microenvironment mediated drug resistance (EMDR) significantly enhances the probability and heterogeneity of resistant clones arising under treatment. Further, the model predicts that targeting of EMDR deepens therapy response by eliminating sensitive clones proximal to stroma and bone, a finding supported by in vivo studies. Altogether, our model allows for the study of MM clonal evolution over time in the bone microenvironment and will be beneficial for optimizing treatment efficacy so as to significantly delay disease relapse.

AOA Critical Issues Symposium: Gun Violence as a Public Health Crisis.

ABSTRACT: Gun violence is an epidemic throughout the United States and is increasing around the world-it is a public health crisis. The impact of gun violence is not limited to the victims (our patients); it also extends to the physicians and caregivers who are taking care of these patients every day. Even more broadly, gun violence affects those living and going to work in potentially dangerous environments. The "vicarious trauma" that is experienced in these situations can have long-term effects on physicians, nurses, and communities. Importantly, socioeconomic disparities and community deprivation strongly correlate with gun violence. Systemic factors that are deeply ingrained in our society can increase concerns for these underrepresented patient populations and cause increased stressors with substantial health consequences, including delayed fracture-healing and poorer overall health outcomes. It is incumbent on us as physicians to take an active role in speaking up for our patients. The importance of advocacy efforts to change policy (not politics) and continue to push for improvement in the increasingly challenging environments in which patients and physicians find themselves cannot be overstated. Multiple national organizations, including many orthopaedic and general surgery associations, have made statements advocating for change. The American College of Surgeons, in collaboration with many other medical organizations, has supported background checks, registration, licensure, firearm education and training, safe storage practices, red flag laws, addressing mental health issues, and more research to better inform an approach going forward and to address the root causes of violence. We encourage the orthopaedic surgery community to stand together to protect each other and our patients, both physically and mentally, with agreement on these principles.

Do Women and Minority Orthopaedic Residents Report Experiencing Worse Well-being and More Mistreatment Than Their Peers?

BACKGROUND: Despite the increased risk of attrition for women and minority residents during orthopaedic residency, there is currently a paucity of research examining the training environment of these residents. To address this, we examined how well-being constructs may differ for women or minority residents compared with their peers, and whether these residents report experiencing more mistreatment during residency. QUESTIONS/PURPOSES: (1) How does the psychologic wellbeing of women and minority residents compare with that of their peers regarding the constructs of burnout, lifestyle satisfaction, social belonging, and stereotype threat? (2) Do reported mistreatment experiences during residency differ among women and minority residents compared with their peers? (3) Is there a difference in the proportion of women and minority orthopaedic residents with thoughts of leaving residency compared with their peers? METHODS: Seventeen orthopaedic residency programs in the 91 programs comprising the Collaborative Orthopaedic Educational Research Group agreed to participate in the study. Program directors sent an anonymous one-time survey with two reminders to all orthopaedic residents at their respective institutions. The survey instrument comprised validated and previously used instruments with face validity designed to measure burnout, satisfaction, duty-hour violations, belonging, stereotype threat, mistreatment, and thoughts of leaving residency, in addition to demographic information. Forty-three percent (211 of 491) of residents responded to the survey. Race or ethnicity data were combined into "White" and "underrepresented in orthopaedics" (URiO), which included residents who self-identified as Asian, African American, Hispanic or Latino, Native American, or other, given that these groups are all underrepresented racial and ethnic groups in orthopaedics. The demographic makeup of our study, 81% men and 75% White, is roughly comparable to the current demographic makeup of orthopaedic residency programs, which is 82% men and 74% White. Data were analyzed using chi-square tests, Fisher exact tests, and t-tests as appropriate. For comparisons of Likert scale measures, we used an anchor-based approach to determining the minimum detectable change (MDC) and set the MDC as a 1-point difference on a 5-point scale and a 1.5-point difference on a 7-point scale. Stereotype threat is reported as the mean ▵ from the neutral response, and ▵ of 1.5 or greater was considered significant. RESULTS: Women residents were more likely than men to report experiencing emotional exhaustion (odds ratio 2.18 [95% confidence interval 1.1 to 4.5]; p = 0.03). Women reported experiencing stereotype threat regarding their identity as women surgeons (mean ▵ 1.5 ± 1.0). We did not identify a difference in men's and women's overall burnout (OR 1.4 [95% CI 0.7 to 3.0]; p = 0.3), lifestyle satisfaction across multiple domains, or sense of social belonging (men: 4.3, women 3.6; mean difference 0.7 [95% CI 0.4 to 0.9]; p < 0.001). We did not identify differences in overall burnout (OR 1.5 [95% CI 0.8 to 3.0]; p = 0.2), lifestyle satisfaction across multiple domains, sense of social belonging (White: 4.2, URiO: 3.9; mean difference 0.3 [95% CI 0.17 to 0.61]; p < 0.001), or stereotype threat (mean ▵ 0.8 ± 0.9) between White and URiO surgeons. Women were more likely than men to report experiencing mistreatment, with 84% (32 of 38) of women and 43% (70 of 164) of men reporting mistreatment at least a few times per year (OR 7.2 [95% CI 2.8 to 18.1]; p < 0.001). URiO residents were more likely than White residents to report experiencing mistreatment overall, with 65% (32 of 49) of URiO residents and 45% (66 of 148) of White residents reporting occurrences at least a few times per year (OR 2.3 [95% CI 1.2 to 4.6]; p = 0.01). Women were more likely than men to report experiencing gender discrimination (OR 52.6 [95% CI 18.9 to 146.1]; p < 0.001), discrimination based on pregnancy or childcare status (OR 4.3 [95% CI 1.4 to 12.8]; p = 0.005), and sexual harassment (OR 11.8 [95% CI 4.1 to 34.3]; p < 0.001). URiO residents were more likely than White residents to report experiencing racial discrimination (OR 7.8 [95% CI 3.4 to 18.2]; p < 0.001). More women than men had thoughts of leaving residency (OR 4.5 [95% CI 1.5 to 13.5]; p = 0.003), whereas URiO residents were not more likely to have thoughts of leaving than White residents (OR 2.2 [95% CI 0.7 to 6.6]; p = 0.1). CONCLUSION: Although we did not detect meaningful differences in some measures of well-being, we identified that women report experiencing more emotional exhaustion and report stereotype threat regarding their identity as women surgeons. Women and URiO residents report more mistreatment than their peers, and women have more thoughts of leaving residency than men. These findings raise concern about some aspects of the training environment for women and URiO residents that could contribute to attrition during training. CLINICAL RELEVANCE: Understanding how well-being and mistreatment affect underrepresented residents helps in developing strategies to better support women and URiO residents during training. We recommend that orthopaedic governing bodies consider gathering national data on resident well-being and mistreatment to identify specific issues and track data over time. Additionally, departments should examine their internal practices and organizational culture to address specific gaps in inclusivity, well-being, and mechanisms for resident support.

American Association for the Surgery of Trauma/American College of Surgeons Committee on Trauma: Clinical protocol for damage-control resuscitation for the adult trauma patient.

ABSTRACT: Damage-control resuscitation in the care of critically injured trauma patients aims to limit blood loss and prevent and treat coagulopathy by combining early definitive hemorrhage control, hypotensive resuscitation, and early and balanced use of blood products (hemostatic resuscitation) and the use of other hemostatic agents. This clinical protocol has been developed to provide evidence-based recommendations for optimal damage-control resuscitation in the care of trauma patients with hemorrhage.

Enantioselective Total Synthesis of (+)-Incargranine A Enabled by Bifunctional Iminophosphorane and Iridium Catalysis.

Herein we report the first enantioselective total synthesis of (+)-incargranine A, in nine steps. The total synthesis was enabled by an enantioselective intramolecular organocatalysed desymmetrising Michael addition of a malonamate ester to a linked dienone substrate that established pivotal stereocentres with excellent enantio- and complete diastereoselectivity. Furthermore, a key hemiaminal intermediate was accessed by developing an iridium-catalysed reductive cyclisation, and the scope of this transformation was explored to produce a range of bicyclic hemiaminal motifs. Once installed, the hemiaminal motif was used to initiate a biomimetic cascade to access the natural product directly in a single step.

Outcomes of Humerus Nonunion Surgery in Patients With Initial Operative Fracture Fixation.

OBJECTIVES: To describe outcomes following humerus aseptic nonunion surgery in patients whose initial fracture was treated operatively and to identify risk factors for nonunion surgery failure in the same population. DESIGN: Retrospective case series. SETTING: Eight, academic, level 1 trauma centers. PATIENTS SELECTION CRITERIA: Patients with aseptic humerus nonunion (OTA/AO 11 and 12) after the initial operative management between 1998 and 2019. OUTCOME MEASURES AND COMPARISONS: Success rate of nonunion surgery. RESULTS: Ninety patients were included (56% female; median age 50 years; mean follow-up 21.2 months). Of 90 aseptic humerus nonunions, 71 (78.9%) united following nonunion surgery. Thirty patients (33.3%) experienced 1 or more postoperative complications, including infection, failure of fixation, and readmission. Multivariate analysis found that not performing revision internal fixation during nonunion surgery (n = 8; P = 0.002) and postoperative de novo infection (n = 9; P = 0.005) were associated with an increased risk of recalcitrant nonunion. Patient smoking status and the use of bone graft were not associated with differences in the nonunion repair success rate. CONCLUSIONS: This series of previously operated aseptic humerus nonunions found that more than 1 in 5 patients failed nonunion repair. De novo postoperative infection and failure to perform revision internal fixation during nonunion surgery were associated with recalcitrant nonunion. Smoking and use of bone graft did not influence the success rate of nonunion surgery. These findings can be used to give patients a realistic expectation of results and complications following humerus nonunion surgery. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Disentangling the intersection of inequities with health and malaria exposure: key lessons from rural communities in Northern Borneo.

BACKGROUND: The increasing incidence of Plasmodium knowlesi malaria poses a significant challenge to efforts to eliminate malaria from Malaysia. Macaque reservoirs, outdoors-biting mosquitoes, human activities, and agricultural work are key factors associated with the transmission of this zoonotic pathogen. However, gaps in knowledge regarding reasons that drive malaria persistence in rural Kudat, Sabah, Northern Borneo remain. This study was conducted to address this knowledge gap, to better understand the complexities of these entangled problems, and to initiate discussion regarding new countermeasures to address them. This study aims to highlight rural community members' perspectives regarding inequities to health relating to P. knowlesi malaria exposure. METHODS: From January to October 2022, a study using qualitative methods was conducted in four rural villages in Kudat district of Sabah, Malaysia. A total of nine in-depth interviews were conducted with community and faith leaders, after the completion of twelve focus group discussions with 26 photovoice participants. The interviews were conducted using the Sabah Malay dialect, audio-recorded, transcribed, and translated into English. The research team led the discussion and analysis, which was approved by participants through member checking at the community level. RESULTS: Participants identified disparity in health as a key issue affecting their health and livelihoods. Injustice in the social environment was also identified as a significant challenge, including the importance of listening to the voices of affected communities in disentangling the social and economic phenomena that can impact malaria control. Specific concerns included inadequate access to health-related resources and degradation of the environment. Participants recommended improving access to water and other necessities, increasing the availability of malaria control commodities in healthcare facilities, and developing sustainable programs to reduce socioeconomic disparities. CONCLUSION: Inequities to health emerged as a key concern for malaria control in rural Kudat, Sabah. A locally targeted malaria programme cantered on improving the social and economic disparities associated with health outcomes, could be a potential strategy for malaria prevention in such areas. Community-level perspectives gathered from this study can be used as a foundation for future discussions and dialogues among policymakers and community members for achieving greater transparency, improving social equity, and interoperability in addressing P. knowlesi malaria control.

Prevalence and Determinants of Undiagnosed Liver Steatosis and Fibrosis in a Nationally Representative Sample of US Adults.

Background Chronic liver diseases account for approximately 1.9 million deaths globally every year and negatively affect health-related quality of life. Early detection of liver disease may enable timely treatment, potentially improving patient outcomes. This study aimed to determine the prevalence and determinants of liver steatosis and fibrosis in US adults with no previously diagnosed liver condition. Methods We conducted an observational, nationally representative, cross-sectional study using data from the National Health and Nutrition Examination Survey (NHANES) conducted from January 2017 to March 2020. Study participants were 7,391 adults aged 21 and older with no history of diagnosed liver disorders who underwent vibration-controlled transient elastography (VCTE) to determine liver steatosis and fibrosis. Controlled attenuation parameter (CAP) values between 248 and 267 dB/m were classified as mild steatosis, and those over 267 dB/m as advanced steatosis. Liver stiffness measurement (LSM) values between 7.65 and 13 kPa were classified as moderate/severe fibrosis, and those over 13 kPa as cirrhosis. Covariates included age, sex, race, body mass index (BMI), diabetes mellitus, kidney disease, smoking history, alcohol intake, alanine aminotransferase (ALT), aspartate aminotransferase (AST), physical activity, sedentary time, and sleep time. The associations of subject characteristics with liver CAP and LSM were evaluated using survey multivariable linear regression. Shapley Additive Explanations values determined the relative importance of each attribute in the model. The discriminative performance of classification models was assessed using the area under the receiver operating characteristic (AUROC) curve. Results The population prevalence of liver steatosis was 57.2% (10.2% mild; 47.0% advanced). The relative importance of covariates in predicting liver CAP was 63.1% for BMI, 10.7% for ALT, and less than 10% for the other covariates. The prevalence of significant fibrosis was 11.4% (8.3% moderate/severe fibrosis; 3.1% cirrhosis). The relative importance of covariates in predicting LSM was 67.3% for BMI and less than 10% for the other covariates. BMI alone demonstrated acceptable discriminative performance in classifying varying severities of steatosis and fibrosis (AUROC range 72%-78%) at cutoffs between 28 and 33 kg/m2. Conclusions Undiagnosed chronic liver disease based on VCTE findings is highly prevalent among US adults, particularly in obese individuals. Efforts to increase awareness about liver disease and to reconsider existing BMI thresholds for liver disease screening may be warranted.

Combining camera trap surveys and IUCN range maps to improve knowledge of species distributions.

Reliable maps of species distributions are fundamental for biodiversity research and conservation. The International Union for Conservation of Nature (IUCN) range maps are widely recognized as authoritative representations of species' geographic limits, yet they might not always align with actual occurrence data. In recent area of habitat (AOH) maps, areas that are not habitat have been removed from IUCN ranges to reduce commission errors, but their concordance with actual species occurrence also remains untested. We tested concordance between occurrences recorded in camera trap surveys and predicted occurrences from the IUCN and AOH maps for 510 medium- to large-bodied mammalian species in 80 camera trap sampling areas. Across all areas, cameras detected only 39% of species expected to occur based on IUCN ranges and AOH maps; 85% of the IUCN only mismatches occurred within 200 km of range edges. Only 4% of species occurrences were detected by cameras outside IUCN ranges. The probability of mismatches between cameras and the IUCN range was significantly higher for smaller-bodied mammals and habitat specialists in the Neotropics and Indomalaya and in areas with shorter canopy forests. Our findings suggest that range and AOH maps rarely underrepresent areas where species occur, but they may more often overrepresent ranges by including areas where a species may be absent, particularly at range edges. We suggest that combining range maps with data from ground-based biodiversity sensors, such as camera traps, provides a richer knowledge base for conservation mapping and planning.

Combinación de censos con fototrampas y mapas de extensión de la UICN para incrementar el conocimiento sobre la distribución de las especies Resumen Los mapas confiables de la distribución de las especies son fundamentales para la investigación y conservación de la biodiversidad. Los mapas de distribución de la Unión Internacional para la Conservación de la Naturaleza (UICN) están reconocidos como representaciones de autoridad de los límites geográficos de las especies, aunque no siempre se alinean con los datos actuales de su presencia. En los mapas recientes de área de hábitat (ADH), las áreas que no son hábitat han sido eliminadas de la distribución de la UICN para reducir los errores de comisión, pero su concordancia con la presencia actual de las especies tampoco ha sido analizada. Analizamos la concordancia entre la presencia registrada por los censos de fototrampas y pronosticamos la presencia a partir de los mapas de la UICN y de ADH de 510 especies de mamíferos de talla mediana a grande en 80 áreas de muestreo de fototrampas. Las cámaras detectaron sólo el 39% de las especies esperadas con base en la distribución de la UICN y los mapas de ADH en todas las áreas; el 85% de las disparidades con la UICN ocurrieron dentro de los 200 km a partir del borde de la distribución. Sólo el 4% de la presencia de las especies fue detectada por las cámaras ubicadas fuera de la distribución de la UICN. La probabilidad de disparidad entre las cámaras y la UICN fue significativamente mayor para los mamíferos de talla pequeña y para los especialistas de hábitat en las regiones Neotropical e Indomalaya y en áreas con doseles forestales más bajos. Nuestros hallazgos sugieren que los mapas de distribución y ADH pocas veces subrepresentan las áreas con presencia de las especies, pero con frecuencia pueden sobrerrepresentar la distribución al incluir áreas en donde las especies pueden estar ausentes, en particular los bordes de la distribución. Sugerimos que la combinación de los mapas de distribución con los sensores de biodiversidad en tierra, como las fototrampas, proporciona una base más rica de conocimiento para el mapeo y la planeación de la conservación.

Wood cookstove use is associated with gastric cancer in Central America and mediated by host genetics.

Biomass cookstove food preparation is linked to aero-digestive cancers, mediated by ingested and inhaled carcinogens (e.g., heterocyclic amines, and polycyclic aromatic hydrocarbons). We investigated the association between gastric adenocarcinoma, wood cookstove use, H. pylori CagA infection and risk modification by variants in genes that metabolize and affect the internal dose of carcinogens. We conducted a population-based, case-control study (814 incident cases, 1049 controls) in rural Honduras, a high-incidence region with a homogeneous diet and endemic H. pylori infection, primarily with the high-risk CagA genotype. We investigated factors including wood cookstove use, H. pylori CagA serostatus, and 15 variants from 7 metabolizing genes, and the interactions between wood stove use and the genetic variants. Male sex (OR 2.0, 1.6-2.6), age (OR 1.04, 1.03-1.05), wood cookstove use (OR 2.3, 1.6-3.3), and CagA serostatus (OR 3.5, 2.4-5.1) and two SNPs in CYP1B1 (rs1800440 and rs1056836) were independently associated with gastric cancer in multivariate analysis. In the final multivariate model, a highly significant interaction (OR 3.1, 1.2-7.8) was noted between wood cookstove use and the rs1800440 metabolizing genotype, highlighting an important gene-environment interaction. Lifetime wood cookstove use associates with gastric cancer risk in the high-incidence regions of Central America, and the association is dependent on the rs1800440 genotype in CYP1B1. H. pylori CagA infection, wood cookstove use and the rs1800440 genotype, all of which are highly prevalent, informs who is at greatest risk from biomass cookstove use.

Stroma-Mediated Breast Cancer Cell Proliferation Indirectly Drives Chemoresistance by Accelerating Tumor Recovery between Chemotherapy Cycles.

The ability of tumors to survive therapy reflects both cell-intrinsic and microenvironmental mechanisms. Across many cancers, including triple-negative breast cancer (TNBC), a high stroma/tumor ratio correlates with poor survival. In many contexts, this correlation can be explained by the direct reduction of therapy sensitivity induced by stroma-produced paracrine factors. We sought to explore whether this direct effect contributes to the link between stroma and poor responses to chemotherapies. In vitro studies with panels of TNBC cell line models and stromal isolates failed to detect a direct modulation of chemoresistance. At the same time, consistent with prior studies, fibroblast-produced secreted factors stimulated treatment-independent enhancement of tumor cell proliferation. Spatial analyses indicated that proximity to stroma is often associated with enhanced tumor cell proliferation in vivo. These observations suggested an indirect link between stroma and chemoresistance, where stroma-augmented proliferation potentiates the recovery of residual tumors between chemotherapy cycles. To evaluate this hypothesis, a spatial agent-based model of stroma impact on proliferation/death dynamics was developed that was quantitatively parameterized using inferences from histologic analyses and experimental studies. The model demonstrated that the observed enhancement of tumor cell proliferation within stroma-proximal niches could enable tumors to avoid elimination over multiple chemotherapy cycles. Therefore, this study supports the existence of an indirect mechanism of environment-mediated chemoresistance that might contribute to the negative correlation between stromal content and poor therapy outcomes. SIGNIFICANCE: Integration of experimental research with mathematical modeling reveals an indirect microenvironmental chemoresistance mechanism by which stromal cells stimulate breast cancer cell proliferation and highlights the importance of consideration of proliferation/death dynamics. See related commentary by Wall and Echeverria, p. 3667.

Ketone Bodies Induce Unique Inhibition of Tumor Cell Proliferation and Enhance the Efficacy of Anti-Cancer Agents.

The ketone bodies, sodium and lithium salts of acetoacetate (AcAc) and sodium 3-hydroxybutyrate (3-HB; commonly called beta-hydroxybutyrate) have been found to inhibit the proliferation of cancer cells. Previous studies have suggested that lithium itself may be an inhibiting agent but may be additive or synergistic with the effect of AcAc. We previously found that sodium acetoacetate (NaAcAc) inhibits the growth of human colon cancer cell line SW480. We report here similar results for several other cancer cell lines including ovarian, cervical and breast cancers. We found that NaAcAc does not kill cancer cells but rather blocks their proliferation. Similar inhibition of growth was seen in the effect of lithium ion alone (as LiCl). The effect of LiAcAc appears to be due to the combined effects of acetoacetate and the lithium ion. The ketone bodies, when given together with chemotherapeutic agents, rapamycin, methotrexate and the new peptide anti-cancer agent, PNC-27, substantially lowers their IC50 values for cancer cell, killing suggesting that ketone bodies and ketogenic diets may be powerful adjunct agents in treating human cancers.

Computed tomography assessment of pelvic bone density: Associations with age and pelvic fracture in motor vehicle crashes.

Motor vehicle crash (MVC) occupants routinely get a computed tomography (CT) scan to screen for internal injury, and this CT can be leveraged to opportunistically derive bone mineral density (BMD). This study aimed to develop and validate a method to measure pelvic BMD in CT scans without a phantom, and examine associations of pelvic BMD with age and pelvic fracture incidence in seriously injured MVC occupants from the Crash Injury Research and Engineering Network (CIREN) study. A phantom-less muscle-fat calibration technique to measure pelvic BMD was validated using 45 quantitative CT scans with a bone calibration phantom. The technique was then used to measure pelvic BMD from CT scans of 252 CIREN occupants (ages 16+) in frontal MVCs who had sustained either abdominal or pelvic injury. Pelvic BMD was analyzed in relation to age and pelvic fracture incidence. In the validation set, phantom-based calibration vs. phantom-less muscle-fat calibration yielded similar BMD values at the anterior superior iliac spine (ASIS; R2 = 0.95, p < 0.001) and iliac crest (R2 = 0.90, p < 0.001). Pelvic BMD was measured in 150 female and 102 male CIREN occupants aged 16-89, and 25% of these occupants sustained pelvic fracture. BMD at the ASIS and iliac crest declined with age (p < 0.001). For instance, iliac crest BMD decreased an average of 25 mg/cm3 per decade of age. The rate of iliac crest BMD decline was 7.6 mg/cm3 more per decade of age in occupants with pelvic fracture compared to those not sustaining pelvic fracture. Findings suggest pelvic BMD may be a contributing risk factor for pelvic fracture in MVCs.

Support for management actions to protect night sky quality: Insights from visitors to state and national park units in the U.S.

Light pollution is a global phenomenon where anthropogenic light sources continue to grow unabated, affecting both social and ecological systems. This is leaving parks and protected areas as some of the last vestiges of naturally dark environments for protecting views of the night sky. Yet, even parks and protected areas have outdoor lighting. Alternative lighting practices are needed to reduce or prevent light pollution from within parks. However, making parks darker may not be desirable for some visitors if they believe it will reduce navigability, safety, or restrict how they recreate (e.g., requiring the use of red-light flashlights after dark and before dawn). How visitors will respond to alternative lighting practices that park managers can implement is still unknown. We used an on-site intercept survey at nine state and national park units in Utah, U.S., to investigate nighttime visitors' support or opposition to management actions to protect night sky quality and their interest in learning about topics related to night skies. Further, this study also segmented visitors into two groups: those 'dependent' on the dark sky as a resource and those whose activities did not depend on a dark sky. Defining what a 'dark sky dependent' visitor is, which has yet to be done in the literature, is a fundamental step to furthering night sky research and management efforts. Across nine parks and protected areas, 62% of nighttime visitors participated in dark sky dependent activities. Findings indicate broad support for management actions designed to improve night sky quality, with between 74% and 89% of all visitors supporting seven different management actions. There was stronger support from dark sky dependent visitors for some elements of alternative lighting practices, but there was still strong support for those who do not participate in dark sky dependent outdoor recreation. Additionally, between 57% and 75% of visitors were interested in learning more about topics related to night skies. This research indicates most visitors would welcome actions to preserve the quality of the rapidly dwindling naturally dark experiences offered by parks and protected areas.

Clinical Practice Guideline Recommendations in Pediatric Orthopaedic Injury: A Systematic Review.

BACKGROUND: Lack of adherence to recommendations on pediatric orthopaedic injury care may be driven by lack of knowledge of clinical practice guidelines (CPGs), heterogeneity in recommendations or concerns about their quality. We aimed to identify CPGs for pediatric orthopaedic injury care, appraise their quality, and synthesize the quality of evidence and the strength of associated recommendations. METHODS: We searched Medline, Embase, Cochrane CENTRAL, Web of Science and websites of clinical organizations. CPGs including at least one recommendation targeting pediatric orthopaedic injury populations on any diagnostic or therapeutic intervention developed in the last 15 years were eligible. Pairs of reviewers independently extracted data and evaluated CPG quality using the Appraisal of Guidelines Research and Evaluation (AGREE) II tool. We synthesized recommendations from high-quality CPGs using a recommendations matrix based on the GRADE Evidence-to-Decision framework. RESULTS: We included 13 eligible CPGs, of which 7 were rated high quality. Lack of stakeholder involvement and applicability (i.e., implementation strategies) were identified as weaknesses. We extracted 53 recommendations of which 19 were based on moderate or high-quality evidence. CONCLUSIONS: We provide a synthesis of recommendations from high-quality CPGs that can be used by clinicians to guide treatment decisions. Future CPGs should aim to use a partnership approach with all key stakeholders and provide strategies to facilitate implementation. This study also highlights the need for more rigorous research on pediatric orthopaedic trauma. LEVEL OF EVIDENCE: Level II-therapeutic study.