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.

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.

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.

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.

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.

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.

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.].

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.

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.

Intermittent PTHrP(1-34) exposure augments chondrogenesis and reduces hypertrophy of mesenchymal stromal cells.

Phenotype instability and premature hypertrophy prevent the use of human mesenchymal stromal cells (MSCs) for cartilage regeneration. Aim of this study was to investigate whether intermittent supplementation of parathyroid hormone-related protein (PTHrP), as opposed to constant treatment, can beneficially influence MSC chondrogenesis and to explore molecular mechanisms below catabolic and anabolic responses. Human MSCs subjected to chondrogenic induction in high-density culture received PTHrP(1-34), forskolin, dbcAMP, or PTHrP(7-34) either constantly or via 6-h pulses (three times weekly), before proteoglycan, collagen type II, and X deposition; gene expression; and alkaline phosphatase (ALP) activity were assessed. While constant application of PTHrP(1-34) suppressed chondrogenesis of MSCs, pulsed application significantly increased collagen type 2 (COL2A1) gene expression and the collagen type II, proteoglycan, and DNA content of pellets after 6 weeks. Collagen type 10 (COL10A1) gene expression was little affected but Indian hedgehog (IHH) expression and ALP activity were significantly downregulated by pulsed PTHrP. A faster response to PTHrP exposure was recorded for ALP activity over COL2A1 regulation, suggesting that signal duration is critical for catabolic versus anabolic reactions. Stimulation of cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling by forskolin reproduced major effects of both treatment modes, whereas application of PTHrP(7-34) capable of protein kinase C (PKC) signaling was ineffective. Pulsed PTHrP exposure of MSCs stimulated chondrogenesis and reduced endochondral differentiation apparently uncoupling chondrogenic matrix deposition from hypertrophic marker expression. cAMP/PKA was the major signaling pathway triggering the opposing effects of both treatment modes. Intermittent application of PTHrP represents an important novel means to improve chondrogenesis of MSCs and may be considered as a supporting clinical-treatment mode for MSC-based cartilage defect regeneration.

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.

Molecular flexibility and structural instabilities in crystalline l-methionine.

We have investigated the dynamics in polycrystalline samples of l-methionine related to the structural transition at about 307K by incoherent inelastic and quasielastic neutron scattering, X-ray powder diffraction as well as ab-initio calculations. l-Methionine is a sulfur amino acid which can be considered a derivative of alanine with the alanine R-group CH3 exchanged by CH3S(CH2)2. Using X-ray powder diffraction we have observed at ~190K an anomalous drop of the c-lattice parameter and an abrupt change of the ß-monoclinic angle that could be correlated to the anomalies observed in previous specific heat measurements. Distinct changes in the quasielastic region of the neutron spectra are interpreted as being due to the onset and slowing-down of reorientational motions of the CH3-S group, are clearly distinguished above 130K in crystalline l-methionine. Large-amplitude motions observed at low frequencies are also activated above 275K, while other well-defined vibrations are damped. The ensemble of our results suggests that the crystalline structure of l-methionine is dynamically highly disordered above 275K, and such disorder can be linked to the flexibility of the molecular thiol-ether group.

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.

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.

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.

Observation of subtle dynamic transitions by a combination of neutron scattering, X-ray diffraction and DSC: a case study of the monoclinic L-cysteine.

The paper illustrates the benefit of combining several experimental techniques (incoherent elastic and inelastic neutron scattering, DSC, and X-ray diffraction) to study subtle dynamic transitions in a biologically important system, probing a broad time (frequency) range of the molecular motions in a wide temperature interval of 2-300K. As a case study the crystalline form (a monoclinic polymorph) of l-cysteine ((+)NH(3)-CH(CH(2)SH)-COO(-)) - an essential amino acid - has been selected. Crystals of amino acids are widely used to mimic important structural and dynamic features of peptides. The conformational lability of cysteine and the dynamics of the thiol-side chains are known to account for various phase transitions in the crystalline state and for the conformational transitions important for the biological function in the peptides. The effect of temperature on the monoclinic polymorph of l-cysteine, metastable at ambient conditions, has been studied for the first time. A dynamical transition at about 150K, marking a crossover of the molecular fluctuations between harmonic and non-harmonic dynamical regimes, was evidenced by evaluating the evolution of the mean-square displacement obtained from the elastic fixed window approach using the backscattering spectrometer IN10 located at the ILL. Although this transition does not manifest itself in the DSC, it was clearly observed by incoherent inelastic neutron scattering. By analyzing the dynamical susceptibility contribution (chi''(omega)) obtained using IN6 also at ILL we were able to evidence another relaxation process at a different time scale. The disordered soft l-cysteine structure has an excess of inelastic scattering at about 3meV, analogous to the "boson peak" observed in glass-like materials and proteins. High-precision X-ray diffraction has revealed an anomaly in the changes of selected unit cell parameters and volume at about 240K.