Time-dependent contribution of BMP, FGF, IGF, and HH signaling to the proliferation of mesenchymal stroma cells during chondrogenesis.

Early loss of up to 50% of cells is common for in vitro chondrogenesis of mesenchymal stromal cells (MSC) in pellet culture, reducing the efficacy and the tissue yield for cartilage engineering. Enhanced proliferation could compensate for this unwanted effect, but relevant signaling pathways remain largely unknown. The aim of this study was to identify the contribution of bone morphogenetic protein (BMP), fibroblast growth factor (FGF), insulin-like growth factor (IGF), and hedgehog (HH) signaling toward cell proliferation during chondrogenesis and investigate whether a further mitogenic stimulation is possible and promising. Human MSC were subjected to chondrogenesis in the presence or absence of pathway inhibitors or activators up to Day 14 or from Days 14 to 28, before proliferation, DNA and proteoglycan content were quantified. [3H]-thymidine incorporation revealed arrest of proliferation on Day 3, after which cell division was reinitiated. Although BMP signaling was essential for proliferation throughout chondrogenesis, IGF signaling was relevant only up to Day 14. In contrast, FGF and HH signaling drove proliferation only from Day 14 onward. Early BMP4, IGF-1, or FGF18 treatment neither prevented early cell loss nor allowed further mitogenic stimulation. However, application of the HH-agonist purmorphamine from Day 14 increased proliferation 1.44-fold (p < 0.05) and late BMP4-application enhanced the DNA and proteoglycan content, with significant effects on tissue yield. Conclusively, a differential and phase-dependent contribution of the four pathways toward proliferation was uncovered and BMP4 treatment was promising to enhance tissue yield. Culture forms less prone to size limitations by nutrient/oxygen gradients and a focus on early apoptosis prevention may be considered as the next steps to further enhance chondrocyte formation from MSC.

Extracellular matrix content and WNT/ß-catenin levels of cartilage determine the chondrocyte response to compressive load.

During osteoarthritis (OA)-development extracellular matrix (ECM) molecules are lost from cartilage, thus changing gene-expression, matrix synthesis and biomechanical competence of the tissue. Mechanical loading is important for the maintenance of articular cartilage; however, the influence of an altered ECM content on the response of chondrocytes to loading is not well understood, but may provide important insights into underlying mechanisms as well as supplying new therapies for OA. Objective here was to explore whether a changing ECM-content of engineered cartilage affects major signaling pathways and how this alters the chondrocyte response to compressive loading. Activity of canonical WNT-, BMP-, TGF-ß- and p38-signaling was determined during maturation of human engineered cartilage and followed after exposure to a single dynamic compression-episode. WNT/ß-catenin- and pSmad1/5/9-levels declined with increasing ECM-content of cartilage. While loading significantly suppressed proteoglycan-synthesis and ACAN-expression at low ECM-content this catabolic response then shifted to an anabolic reaction at high ECM-content. A positive correlation was observed between GAG-content and load-induced alteration of proteoglycan-synthesis. Induction of high ß-catenin levels by the WNT-agonist CHIR suppressed load-induced SOX9- and GAG-stimulation in mature constructs. In contrast, the WNT-antagonist IWP-2 was capable of attenuating load-induced GAG-suppression in immature constructs. In conclusion, either ECM accumulation-associated or pharmacologically induced silencing of WNT-levels allowed for a more anabolic reaction of chondrocytes to physiological loading. This is consistent with the role of proteoglycans in sequestering WNT-ligands in the ECM, thus reducing WNT-activity and also provides a novel explanation of why low WNT-activity in cartilage protects from OA-development in mechanically overstressed cartilage.

Role of PTHrP(1-34) Pulse Frequency Versus Pulse Duration to Enhance Mesenchymal Stromal Cell Chondrogenesis.

Generation of phenotypically stable, articular chondrocytes from mesenchymal stromal cells (MSCs) is still an unaccomplished task, with formation of abundant, hyaline extracellular matrix, and avoidance of hypertrophy being prime challenges. We recently demonstrated that parathyroid hormone-related protein (PTHrP) is a promising factor to direct chondrogenesis of MSCs towards an articular phenotype, since intermittent PTHrP application stimulated cartilage matrix production and reduced undesired hypertrophy. We here investigated the role of frequency, pulse duration, total exposure time, and underlying mechanisms in order to unlock the full potential of PTHrP actions. Human MSC subjected to in vitro chondrogenesis for six weeks were exposed to 2.5 nM PTHrP(1-34) pulses from days 7 to 42. Application frequency was increased from three times weekly (3 × 6 h/week) to daily maintaining either the duration of individual pulses (6 h/day) or total exposure time (18 h/week; 2.6 h/day). Daily PTHrP treatment significantly increased extracellular matrix deposition regardless of pulse duration and suppressed alkaline-phosphatase activity by 87%. High total exposure time significantly reduced cell proliferation at day 14. Pulse duration was critically important to significantly reduce IHH expression, but irrelevant for PTHrP-induced suppression of the hypertrophic markers MEF2C and IBSP. COL10A1, RUNX2, and MMP13 expression remained unaltered. Decreased IGFBP-2, -3, and -6 expression suggested modulated IGF-I availability in PTHrP groups, while drop of SOX9 protein levels during the PTHrP-pulse may delay chondroblast formation and hypertrophy. Overall, the significantly optimized timing of PTHrP-pulses demonstrated a vast potential to enhance chondrogenesis of MSC and suppress hypertrophy possibly via superior balancing of IGF- and SOX9-related mechanisms. J. Cell. Physiol. 231: 2673-2681, 2016. © 2016 Wiley Periodicals, Inc.

Parathyroid hormone-related protein activates Wnt signaling to specify the embryonic mammary mesenchyme.

Parathyroid hormone-related protein (PTHrP) regulates cell fate and specifies the mammary mesenchyme during embryonic development. Loss of PTHrP or its receptor (Pthr1) abolishes the expression of mammary mesenchyme markers and allows mammary bud cells to revert to an epidermal fate. By contrast, overexpression of PTHrP in basal keratinocytes induces inappropriate differentiation of the ventral epidermis into nipple-like skin and is accompanied by ectopic expression of Lef1, ß-catenin and other markers of the mammary mesenchyme. In this study, we document that PTHrP modulates Wnt/ß-catenin signaling in the mammary mesenchyme using a Wnt signaling reporter, TOPGAL-C. Reporter expression is completely abolished by loss of PTHrP signaling and ectopic reporter activity is induced by overexpression of PTHrP. We also demonstrate that loss of Lef1, a key component of the Wnt pathway, attenuates the PTHrP-induced abnormal differentiation of the ventral skin. To characterize further the contribution of canonical Wnt signaling to embryonic mammary development, we deleted ß-catenin specifically in the mammary mesenchyme. Loss of mesenchymal ß-catenin abolished expression of the TOPGAL-C reporter and resulted in mammary buds with reduced expression of mammary mesenchyme markers and impaired sexual dimorphism. It also prevented the ectopic, ventral expression of mammary mesenchyme markers caused by overexpression of PTHrP in basal keratinocytes. Therefore, we conclude that a mesenchymal, canonical Wnt pathway mediates the PTHrP-dependent specification of the mammary mesenchyme.

Polymorphism of paracetamol: a new understanding of molecular flexibility through local methyl dynamics.

This study focuses on the interplay of molecular flexibility and hydrogen bonding manifested in the monoclinic (form I) and orthorhombic (form II) polymorphs of paracetamol. By means of incoherent inelastic neutron scattering and density functional theory calculations, the relaxation processes related to the methyl side-group reorientation were analyzed in detail. Our computational study demonstrates the importance of considering quantum effects to explain how methyl reorientations and subtle conformational changes of the molecule are intertwined. Indeed, by analyzing the quasi elastic signal of the neutron data, we were able to show a unique and complex motional flexibility in form II, reflected by a coupling between the methyl and the phenyl reorientation. This is associated with a higher energy barrier of the methyl rotation and a lower Gibbs free energy when compared to form I. We put forward the idea that correlating solubility and molecular flexibility, through the relation between pKa and methyl rotation activation energy, might bring new insights to understanding and predicting drug bioavailability.

Beyond the Slopes and Highways: Endovascular Repair of Blunt Traumatic Aortic Injuries after Skiing versus Motor Vehicle Accidents.

Background: Blunt traumatic aortic injury (BTAI) is a potentially fatal condition, typically resulting from high-velocity trauma. To date, little is known about this type of injury among skiers, who form the largest patient cohort with aortic injuries in the alpine region of Tyrol, Austria. Methods: This retrospective, single-center study at the University Hospital of Innsbruck analyzed patients who underwent endovascular treatment for blunt traumatic aortic injury from 2005 to 2023. Patient data were extracted from electronic and digitalized medical history records. Subsequent analyses compared the baseline characteristics and clinical results of the skiing accident (SA) group to the motor vehicle accident (MVA) group. Results: A total of 48 BTAI patients receiving TEVAR were included, 25 (52%) from SAs versus 23 (48%) from MVAs, who were predominantly male (92% vs. 78.3%). Despite similar preoperative risk profiles and ASA Scores (1.44 vs. 1.74) and no marked differences in BTAI injury grades or the affected aortic zones, significant disparities emerged: the SA group experienced shorter median ICU stays (3 vs. 11 days, p = 0.0007), fewer concomitant injuries (5 vs. 7, p = 0.005), and lower Injury Severity Scores (ISSs) (29 vs. 33, p = 0.003) than their MVA counterparts. The presence of rib fractures alongside other thoracic injuries, such as lung injury, pneumothorax, or hemothorax, was strongly correlated with BTAI in patients following skiing accidents (OR = 128.5). Conclusions: The injury severities and locations of BTAI in SA patients were comparable to those in MVA patients, indicating similar mechanisms of thoracic trauma. However, the SA patients experienced fewer concurrent pelvic and extremity fractures, had less post-procedural morbidity, and required shorter ICU stays. The presence of rib fractures combined with other thoracic injuries strongly suggests BTAI. These indicators should lead to prompt imaging and appropriate therapy.

Physician stress in the era of COVID-19 vaccine disparity: a multi-institutional survey.

CONTEXT: Healthcare workers are at a high risk of infection during infectious disease outbreaks, such as the COVID-19 pandemic. Despite the availability of several vaccines against COVID-19, the absence of vaccination in patients and colleagues remains a continuous source of stress in healthcare workers. We conducted a survey of physician preceptors, both MDs and DOs, to explore the impact of differences in the patients' and colleagues' vaccination status on their well-being, stress, and burnout. OBJECTIVES: The objective of this study is to determine whether exposure to unvaccinated patients and/or colleagues increases stress and burnout in physician preceptors by utilizing a self-reported survey. METHODS: This multi-institutional study was carried out in the United States in 2022. An online survey questionnaire was utilized to collect data from physicians working as preceptors for multiple academic institutions. The anonymous Qualtrics® survey utilized a modified version of the questionnaire from the expanded Physician Well-being Index (ePWBI) designed by MedEd Web Solutions (MEWS). Statistical analysis on both descriptive and qualitative data were performed. Utilizing a threshold of p≤0.05, data analysis revealed many statistically significant relationships between the variables. RESULTS: A total of 218 physician preceptors completed the survey. The survey results showed that physicians overwhelmingly (p < 0.001) felt that all patients (and healthcare workers) should be vaccinated. The results also indicated that physicians experienced more stress when working with unvaccinated patients (p<0.001), and these stressors were often associated with the physician's gender and age. Furthermore, physicians stated that both their assessment and treatment plans were significantly different for vaccinated vs unvaccinated patients (p=0.039 and p=0.0167, respectively). Most importantly, stress levels (p<0.001) and burnout characteristics (p=0.024) were noted by physicians, both in themselves and in their colleagues. CONCLUSIONS: Findings suggest that physician stress and burnout is a common theme due to the differences in vaccination status of patients admitted to COVID-19 clinics. Due to a more rapid progression of COVID-19 in unvaccinated patients, treatment plans for vaccinated vs unvaccinated patients were also considerably different.

Application of incoherent inelastic neutron scattering in pharmaceutical analysis: relaxation dynamics in phenacetin.

This study centers on the use of inelastic neutron scattering as an alternative tool for physical characterization of solid pharmaceutical drugs. On the basis of such approach, relaxation processes in the pharmaceutical compound phenacetin (p-ethoxyacetanilide, C(10)H(13)NO(2)) were evidenced on heating between 2 and 300 K. By evaluating the mean-square displacement obtained from the elastic fixed window approach, using the neutron backscattering technique, a crossover of the molecular fluctuations between harmonic and nonharmonic dynamical regimes around 75 K was observed. From the temperature dependence of the quasi-elastic line-width, summed over the total Q range explored by the time-of-flight technique, it was possible to attribute the onset of this anharmonicity to methyl group rotations. Finally, using density functional theory-based methods, we were able to calculate the lattice vibrations in the harmonic approximation. The overall spectral profile of the calculated partial contributions to the generalized density of states compares satisfactorily to the experimental spectra in the region of the lattice modes where the intermolecular interactions are expected to play an important role. This study contributes to understanding the relationships between intermolecular hydrogen bonds, intramolecular dynamics, and conformational flexibility in pharmaceuticals on a molecular level, which can help in evaluating phase stability with respect to temperature variations on processing or on storage, and is related to control of polymorphism and pseudopolymorphism.

Physician perceptions of the role and value of basic science knowledge in daily clinical practice.

BACKGROUND: The role of basic science education in a clinical setting remains unclear. Research to understand how academic clinicians perceive and use this part of their education can aid curricular development. AIMS: To assess physician's attitudes toward the value of science knowledge in their clinical practice. METHODS: Academic physicians from three medical schools completed a questionnaire about the utility of basic science education in core clinical tasks and in practice-based learning and improvement. RESULTS: A total of 109 clinical faculty returned the survey. Overall, 89% of the respondents indicated that basic science education is valuable to their clinical practice. When asked about the utility of basic science information in relation to direct patient care, greater than 50% of the doctors felt they use this when diagnosing and communicating with patients. This rose to greater than 60% when asked about choosing treatment options for their patients. Individuals also responded that basic science knowledge is valuable when developing evidence-based best practices. Specifically, 89% felt that they draw upon this information when training students/residents and 84% use this information when reading journal articles. CONCLUSIONS: This study shows that basic science education is perceived by responding academic physicians to be important to their clinical work.

Structure and Dynamics of Ribonuclease A during Thermal Unfolding: The Failure of the Zimm Model.

Disordered regions as found in intrinsically disordered proteins (IDP) or during protein folding define response time to stimuli and protein folding times. Neutron spin-echo spectroscopy is a powerful tool to directly access the collective motions of the unfolded chain to enlighten the physical origin of basic conformational relaxation. During the thermal unfolding of native ribonuclease A, we examine the structure and dynamics of the disordered state within a two-state transition model using polymer models, including internal friction, to describe the chain dynamics. The presence of four disulfide bonds alters the disordered configuration to a more compact configuration compared to a Gaussian chain that is defined by the additional links, as demonstrated by coarse-grained simulation. The dynamics of the disordered chain is described by Zimm dynamics with internal friction (ZIF) between neighboring amino acids. Relaxation times are dominated by mode-independent internal friction. Internal friction relaxation times show an Arrhenius-like behavior with an activation energy of 33 kJ/mol. The Zimm dynamics is dominated by internal friction and suggest that the characteristic motions correspond to overdamped elastic modes similar to the motions observed for folded proteins but within a pool of disordered configurations spanning the configurational space. For IDP, internal friction dominates while solvent friction and hydrodynamic interactions are smaller corrections.

The Role of Students' Beliefs When Critically Reasoning From Multiple Contradictory Sources of Information in Performance Assessments.

Critical reasoning (CR) when confronted with contradictory information from multiple sources is a crucial ability in a knowledge-based society and digital world. Using information without critically reflecting on the content and its quality may lead to the acceptance of information based on unwarranted claims. Previous personal beliefs are assumed to play a decisive role when it comes to critically differentiating between assertions and claims and warranted knowledge and facts. The role of generic epistemic beliefs on critical stance and attitude in reflectively dealing with information is well researched. Relatively few studies however, have been conducted on the influence of domain-specific beliefs, i.e., beliefs in relation to specific content encountered in a piece of information or task, on the reasoning process, and on how these beliefs may affect decision-making processes. This study focuses on students' task- and topic-related beliefs that may influence their reasoning when dealing with multiple and partly contradictory sources of information. To validly assess CR among university students, we used a newly developed computer-based performance assessment in which the students were confronted with an authentic task which contains theoretically defined psychological stimuli for measuring CR. To investigate the particular role of task- and topic-related beliefs on CR, a purposeful sample of 30 university students took part in a performance assessment and then were interviewed immediately afterward. In the semi-structured cognitive interviews, the participants' task-related beliefs were assessed. Based on qualitative analyses of the interview transcripts, three distinct profiles of decision-making among students have been identified. More specifically, the different types of students' beliefs and attitudes derived from the cognitive interview data suggest their influence on information processing, reasoning approaches and decision-making. The results indicated that the students' beliefs had an influence on their selection, critical evaluation and use of information as well as on their reasoning processes and final decisions.

Significance of MEF2C and RUNX3 Regulation for Endochondral Differentiation of Human Mesenchymal Progenitor Cells.

Guiding progenitor cell development between chondral versus endochondral pathways is still an unachieved task of cartilage neogenesis, and human mesenchymal progenitor cell (MPC) chondrogenesis is considered as a valuable model to better understand hypertrophic development of chondrocytes. Transcription factors Runx2, Runx3, and Mef2c play prominent roles for chondrocyte hypertrophy during mouse development, but little is known on the importance of these key fate-determining factors for endochondral development of human MPCs. The aim of this study was to unravel the regulation of RUNX2, RUNX3, and MEF2C during MPC chondrogenesis, the pathways driving their expression, and the downstream hypertrophic targets affected by their regulation. RUNX2, RUNX3, and MEF2C gene expression was differentially regulated during chondrogenesis of MPCs, but remained low and unregulated when non-hypertrophic articular chondrocytes were differentiated under the same conditions. RUNX3 and MEF2C mRNA and protein levels rose in parallel to hypertrophic marker upregulation, but surprisingly, RUNX2 gene expression changed only by trend and RUNX2 protein remained undetectable. While RUNX3 expression was driven by TGF-ß and BMP signaling, MEF2C responded to WNT-, BMP-, and Hedgehog-pathway inhibition. MEF2C but not RUNX3 levels correlated significantly with COL10A1, IHH, and IBSP gene expression when hypertrophy was attenuated. IBSP was a downstream target of RUNX3 and MEF2C but not RUNX2 in SAOS-2 cells, underlining the capacity of RUNX3 and MEF2C to stimulate osteogenic marker expression in human cells. Conclusively, RUNX3 and MEF2C appeared more important than RUNX2 for human endochondral MPC chondrogenesis. Pathways altering the speed of chondrogenesis (FGF, TGF-ß, BMP) affected RUNX2 or RUNX3, while pathways changing hypertrophy (WNT, PTHrP/HH) regulated mainly MEF2C. Taken together, reduction of MEF2C levels is a new goal to shift human cartilage neogenesis toward the chondral pathway.

Functional performance following an ice bag application to the hamstrings.

This study examined the immediate and short-term (20 minute) effects of 3- and 10-minute ice bag applications to the hamstrings on functional performance as measured by the cocontraction test, shuttle run, and single-leg vertical jump. Forty-two (25 women, 17 men) recreational or collegiate athletes who were free of injury in the lower extremity 6 months before testing and who did not suffer from allergy to cryotherapy were included. Time to completion was measured in seconds for the cocontraction and the shuttle run test. Single-leg vertical jump was measured on the Vertec (Sports Imports, Columbus, Ohio) in centimeters. The 10-minute ice bag application reduced immediate post-application vertical jump performance and increased immediate post and 20-minute post shuttle run time (p

Stimulation of calvarial bone healing with human bone marrow stromal cells versus inhibition with adipose-tissue stromal cells on nanostructured ß-TCP-collagen.

Bioactive functional scaffolds are essential for support of cell-based strategies to improve bone regeneration. Adipose-tissue-derived-stromal cells (ASC) are more accessible multipotent cells with faster proliferation than bone-marrow-derived-stromal-cells (BMSC) having potential to replace BMSC for therapeutic stimulation of bone-defect healing. Their osteogenic potential is, however, lower compared to BMSC, a deficit that may be overcome in growth factor-rich orthotopic bone defects with enhanced bone-conductive scaffolds. Objective of this study was to compare the therapeutic potency of human ASC and BMSC for bone regeneration on a novel nanoparticulate ß-TCP/collagen-carrier (ß-TNC). Cytotoxicity of ß-TCP nanoparticles and multilineage differentiation of cells were characterized in vitro. Cell-seeded ß-TNC versus cell-free controls were implanted into 4 mm calvarial bone-defects in immunodeficient mice and bone healing was quantified by µCT at 4 and 8 weeks. Tissue-quality and cell-origin were assessed by histology. ß-TNC was non-toxic, radiolucent and biocompatible, lent excellent support for human cell persistence and allowed formation of human bone tissue by BMSC but not ASC. Opposite to BMSC, ASC-grafting significantly inhibited calvarial bone healing compared to controls. Bone formation progressed significantly from 4 to 8 weeks only in BMSC and controls yielding 5.6-fold more mineralized tissue in BMSC versus ASC-treated defects. Conclusively, ß-TNC was simple to generate, biocompatible, osteoconductive, and stimulated osteogenicity of BMSC to enhance calvarial defect healing while ASC had negative effects. Thus, an orthotopic environment and ß-TNC could not compensate for cell-autonomous deficits of ASC which should systematically be considered when choosing the right cell source for tissue engineering-based stimulation of bone regeneration. STATEMENT OF SIGNIFICANCE: Bone-marrow-derived-stromal cells (BMSC) implanted on bone replacement materials can support bone defect healing and adipose-tissue-derived-stromal cells (ASC) being more accessible and better proliferating are considered as alternate source. This first standardized comparison of the bone regeneration potency of human ASC and BMSC was performed on a novel nanoparticular ß-TCP-enriched collagen-carrier (ß-TNC) designed to overcome the known inferior osteogenicity of ASC. ß-TNC was non-toxic, biocompatible and osteoconductive supporting human bone formation and defect-closure by BMSC but not ASC. Long-term cell-persistence and the distinct secretome of ASC appear as main reasons why ASC inhibited bone healing opposite to BMSC. Overall, ASC-grafting is at considerable risk of producing negative effects on bone-healing while no such risks are known for BMSC.

Analysis of Nuclear Uracil DNA-Glycosylase (nUDG) Turnover During the Cell Cycle.

Uracil-DNA glycosylases (UDG/UNG) are enzymes that remove uracil from DNA and initiate base-excision repair. These enzymes play a key role in maintaining genomic integrity by reducing the mutagenic events caused by G:C to A:T transition mutations. The recent finding that a family of RNA editing enzymes (AID/APOBECs) can deaminate cytosine in DNA has raised the interest in these base-excision repair enzymes. The methodology presented here focuses on determining the regulation of the nuclear isoform of uracil-DNA glycosylase (nUDG), a 36,000 Da protein. In synchronized HeLa cells, nUDG protein levels decrease to barely detectable levels during the S phase of the cell cycle. Immunoblot analysis of immunoprecipitated or affinity-isolated nUDG reveals ubiquitin-conjugated nUDG when proteolysis is inhibited by agents that block proteasomal-dependent protein degradation.

Electronic Health Record Implementation Is Associated With a Negligible Change in Outpatient Volume and Billing.

The Health Information Technology for Economic and Clinical Health (HITECH) Act mandated that hospitals begin using electronic health records (EHRs). To investigate potential up-coding, we reviewed billing data for changes in patient volumes and up-coding around the time of EHR implementation at our academic medical center. We identified all new, consultation, and return outpatient visits on a monthly basis in the general internal medicine and orthopedics departments at our center. We compared the volume of patient visits and the level of billing coding in these 2 departments before and after their transitions to ambulatory EHRs. Pearson χ2 test was used when appropriate. Patient volumes remained constant during the transition to EHRs. There were small changes in the level of billing coding with EHR implementation. In both departments, these changes accounted for minor, but statistically significant shifts in billing coding (Pearson χ², P < .001). However, the 44.7% relative increase in level 5 coding in our orthopedics department represented only 1.7% of patient visits overall. These findings indicate that lay media reports about an association between dramatic up-coding and EHRs could be misleading.

Analysis of Bony and Internal Organ Injuries Associated With 26,357 Adult Femoral Shaft Fractures and Their Impact on Mortality.

The spectrum of injuries associated with femoral shaft fractures and those injuries' association with mortality have not been well delineated previously. Patients in the National Trauma Data Bank who presented with femoral shaft fractures from 2011 to 2012 were analyzed in 3 age groups (18-39, 40-64, and 65+ years). For each group, modified Charlson Comorbidity Index (CCI), mechanism of injury (MOI), injury severity score (ISS), and associated injuries were reported. Multivariate logistic regression was used to identify predictors of mortality. Among the 26,357 patients with femoral shaft fractures, modified CCIs gradually increased with increasing age category and ISS decreased. Motor vehicle accidents were the most common MOI in the younger 2 age groups, whereas falls were the most common MOI in the 65 years and older age group. The top 3 associated bony injuries for the study cohort as a whole were tibia/fibula (20.5%), ribs/sternum (19.1%), and non-shaft femur (18.9%, of which 5.8% of the total cohort were femoral neck) fractures. The top 3 associated internal organ injuries were lung (18.9%), intracranial (13.5%), and liver (6.2%), injuries. A multivariate mortality analysis showed that increasing age, increasing comorbidity burden, and associated injuries all had independent associations with mortality. The injuries most associated with mortality were thoracic organ injuries (adjusted odds ratio [AOR]=3.53), head injuries (AOR=2.93), abdominal organ injuries (AOR=2.78), and pelvic fractures (AOR=1.80). This study used a large, nationwide sample of trauma patients to profile injuries associated with femoral shaft fractures. Associations between injuries and mortality underscore the importance of these findings. [Orthopedics. 2017; 40(3):e506-e512.].

Tibial shaft fracture: A large-scale study defining the injured population and associated injuries.

This is the first large-scale study to define the injured population and examine associated injuries for patients with tibial shaft fractures. Patients over 18 years of age in the National Trauma Data Bank (NTDB) who presented with tibial shaft fractures during 2011 and 2012 were identified. Modified Charlson Comorbidity Index (CCI), mechanism of injury (MOI), injury severity score (ISS), and specific associated injuries were described. Multivariate logistic regression was used to identify predictors of mortality.

Proteolytic degradation of the nuclear isoform of uracil-DNA glycosylase occurs during the S phase of the cell cycle.

Uracil-DNA glycosylases are enzymes that remove uracil from DNA and initiate base-excision repair. These enzymes play a key role in maintaining genomic integrity by reducing the mutagenic events caused by G:C to A:T transition mutations. The recent finding that a family of RNA editing enzymes (APOBECs) can deaminate cytosine in DNA has raised the interest in these base-excision repair enzymes. This research focuses on the regulation of the nuclear isoform of uracil-DNA glycosylase, a 36000 Da protein that contains a unique 44 amino acid N-terminus. In synchronized HeLa cells, UDG1A protein levels decrease to barely detectable levels during the S phase of the cell cycle. Immunoblot analysis of immunoprecipitated or affinity-isolated UDG1A reveals ubiquitin-conjugated UDG1A when proteolysis is inhibited using N-acetyl-leu-leu-norleu-al or MG132, inhibitors of proteosomal dependent protein degradation. Transient transfection experiments, with histidine-tagged ubiquitin, were used to confirm that endogenous UDG1A is ubiquitinated in vivo. Addition of the nuclear export inhibitor, leptomycin B, prevents ubiquitination and degradation of UDG1A. This indicates that translocation from the nucleus may be a step in UDG1A turnover. Finally, UDG1A protein degradation is prevented when cells are incubated with the cyclin-dependent kinase inhibitor, roscovitine. These results suggest that protein phosphorylation and/or nuclear export participate in the post-translational regulation of UDG1A protein levels.

Naloxone increases ketamine-induced hyperactivity in the open field in female rats.

In considering possible effects of ketamine, and its interactions with drugs that might be administered following ketamine abuse, researchers investigated the effects of administering combinations of saline, naloxone, and/or ketamine on open-field activity levels and frequencies of turning, reverse locomotion, head weaving, and rearing in 50-day-old rats. Female subjects having received ketamine combined with saline showed significant increases in open-field activity as compared with male subjects and subjects having received combinations of saline and/or naloxone. When combined with ketamine, naloxone caused an increase in the aforementioned ketamine-induced hyperactivity in female rats. In addition, ketamine caused increases in turning in female rats and increases in reverse locomotion and head weaving in male and female rats. Decreases in rearing were reported in both males and females with administration of ketamine. In general, naloxone had little, if any, effect on these behaviors. Thus, the primary effect of administration of naloxone reported in this study is an exacerbation of ketamine-induced open-field hyperactivity. The authors discuss the results with respect to indirect effects of ketamine on endogenous opiate and dopamine systems on the aforementioned behaviors. The researchers also consider sex differences and possible precautions when dealing with individuals having ingested psychedelic anesthetics.