bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunohistological Localization of BMP-2, BMP-7, and Their Receptors in Knee Joints with Focal Cartilage Lesions
Authors: Schmal Hagen , Mehlhorn Alexander T. , Pilz Ingo H. , Dovi-Akue David , Kirchhoff Christina , Südkamp Norbert P. , Gerlach Ulrike , Lohrmann Christian , Niemeyer Philipp
Published: January 2012

Introduction. Although it is well known that BMP-2 and BMP-7 play significant roles in cartilage metabolism, data about intra-articular expression and localization of these proteins and their receptors in humans are rare.Methods. Biopsies of synovia and debrided cartilage were taken in patients undergoing autologous chondrocyte implantation. Expression of BMP-2, BMP-7, and their receptors BMPR-1A, BMPR-1B and BMPR-2 were semiquantitatively evaluated by immunohistological staining.Results. BMP-7 was equally highly expressed in all cartilage and synovial biopsies. Increased levels of BMPR-1A, but not of BMPR-1B, and BMPR-2, were found in all synovial and 47% of all cartilage samples (P=0.002). BMP-2 was positively scored in 47% of all cartilage and 40% of all synovial specimens. Defect size, KOSS, Henderson or Kellgren-Lawrence score did not statistically significant correlate with the expression of the analyzed proteins or Mankin and Pritzker scores. Duration of symptoms and localization of lesions were associated with KOSS (P<0.02), but there was no influence of these parameters on protein expression.Conclusions. BMP-2, BMP-7, and BMPR-1A were expressed in cartilage and synovia of knees with focal cartilage lesions. Although defect localization and duration of symptoms decisively influence KOSS, there was no associated alteration of protein expression observed.
Cerebrospinal Fluid BACE1 Activity and Brain Amyloid Load in Alzheimer's Disease
Authors: Grimmer Timo , Alexopoulos Panagiotis , Tsolakidou Amalia , Guo Liang-Hao , Henriksen Gjermund , Yousefi Behrooz H. , Förstl Hans , Sorg Christian , Kurz Alexander , Drzezga Alexander , Perneczky Robert
Published: January 2012

The secretase BACE1 is fundamentally involved in the development of cerebral amyloid pathology in Alzheimer's disease (AD). It has not been studied so far to what extent BACE1 activity in cerebrospinal fluid (CSF) mirrors in vivo amyloid load in AD. We explored associations between CSF BACE1 activity and fibrillar amyloid pathology as measured by carbon-11-labelled Pittsburgh Compound B positron emission tomography ([11C]PIB PET). [11C]PIB and CSF studies were performed in 31 patients with AD. Voxel-based linear regression analysis revealed significant associations between CSF BACE1 activity and [11C]PIB tracer uptake in the bilateral parahippocampal region, the thalamus, and the pons. Our study provides evidence for a brain region-specific correlation between CSF BACE1 activity and in-vivo fibrillar amyloid pathology in AD. Associations were found in areas close to the brain ventricles, which may have important implications for the use of BACE1 in CSF as a marker for AD pathology and for antiamyloid treatment monitoring.
Visual Tracking of Plant Virus Infection and Movement Using a Reporter MYB Transcription Factor That Activates Anthocyanin Biosynthesis
Authors: Bedoya Leonor C. , Martínez Fernando , Orzáez Diego , Daròs José-Antonio
Published: January 2012

Insertion of reporter genes into plant virus genomes is a common experimental strategy to research many aspects of the viral infection dynamics. Their numerous advantages make fluorescent proteins the markers of choice in most studies. However, the use of fluorescent proteins still has some limitations, such as the need of specialized material and facilities to detect the fluorescence. Here, we demonstrate a visual reporter marker system to track virus infection and movement through the plant. The reporter system is based on expression of Antirrhinum majus MYB-related Rosea1 (Ros1) transcription factor (220 amino acids; 25.7 kD) that activates a series of biosynthetic genes leading to accumulation of colored anthocyanins. Using two different tobacco etch potyvirus recombinant clones tagged with Ros1, we show that infected tobacco (Nicotiana tabacum) tissues turn bright red, demonstrating that in this context, the sole expression of Ros1 is sufficient to induce pigment accumulation to a level readily detectable to the naked eye. This marker system also reports viral load qualitatively and quantitatively by means of a very simple extraction process. The Ros1 marker remained stable within the potyvirus genome through successive infectious passages from plant to plant. The main limitation of this marker system is that color output will depend on each particular plant host-virus combination and must be previously tested. However, our experiments demonstrate accurate tracking of turnip mosaic potyvirus infecting Arabidopsis (Arabidopsis thaliana) and either tobacco mosaic virus or potato X virus infecting Nicotiana benthamiana, stressing the general applicability of the method.
TsHKT1;2, a HKT1 Homolog from the Extremophile Arabidopsis Relative Thellungiella salsuginea, Shows K+ Specificity in the Presence of NaCl
Authors: Ali Zahir , Park Hyeong Cheol , Ali Akhtar , Oh Dong-Ha , Aman Rashid , Kropornicka Anna , Hong Hyewon , Choi Wonkyun , Chung Woo Sik , Kim Woe-Yeon , Bressan Ray A. , Bohnert Hans J. , Lee Sang Yeol , Yun Dae-Jin
Published: January 2012

Cellular Na+/K+ ratio is a crucial parameter determining plant salinity stress resistance. We tested the function of plasma membrane Na+/K+ cotransporters in the High-affinity K+ Transporter (HKT) family from the halophytic Arabidopsis (Arabidopsis thaliana) relative Thellungiella salsuginea. T. salsuginea contains at least two HKT genes. TsHKT1;1 is expressed at very low levels, while the abundant TsHKT1;2 is transcriptionally strongly up-regulated by salt stress. TsHKT-based RNA interference in T. salsuginea resulted in Na+ sensitivity and K+ deficiency. The athkt1 mutant lines overexpressing TsHKT1;2 proved less sensitive to Na+ and showed less K+ deficiency than lines overexpressing AtHKT1. TsHKT1;2 ectopically expressed in yeast mutants lacking Na+ or K+ transporters revealed strong K+ transporter activity and selectivity for K+ over Na+. Altering two amino acid residues in TsHKT1;2 to mimic the AtHKT1 sequence resulted in enhanced sodium uptake and loss of the TsHKT1;2 intrinsic K+ transporter activity. We consider the maintenance of K+ uptake through TsHKT1;2 under salt stress an important component supporting the halophytic lifestyle of T. salsuginea.
Vegetation analysis, phenological patterns and chorological affinities in Wadi Qena, Eastern Desert, Egypt
Authors: Salama Fawzy M. , Ahmed Mohamed K. , El‐Tayeh Noha A. , Hammad Sabah A.
Published: January 2012

The present study, which was conducted between 2009 and 2010, provides an analysis of the floristic composition, life forms, phenology, chorological spectrum and analysis of the vegetation in the deltaic part of Wadi Qena using multivariate analysis techniques. Twenty‐five stands were sampled to represent, as much as possible, the vegetation variation in the study area. A total of 54 species (nineteen annuals and 35 perennials) belonging to 47 genera and nineteen families were recorded. The largest families were Fabaceae and Brassicaceae (nine and seven, respectively), Asteraceae and Poaceae (six for each), Chenopodiaceae (five), and Zygophyllaceae (four). Therophytes are the predominant life form (37%) followed by chamaephytes (24%), phanerophytes (18.5%), hemicryptophytes (9.29%) and cryptophytes (5.5%). Chorological analysis revealed that Saharo‐Arabian (48%) and the Sudano‐Zambezian (19.2%) chorotypes constitute the main bulk (67.2%) of the total flora of the studied area. The majority of the perennial species behave similarly to each other in their phenology, and usually perennials sprout at the end of February, become leafy in March, flower in April and produce fruits between April and July. Three main vegetation groups resulted from classification of the dominant vegetation. Canonical correspondence analysis revealed that magnesium, potassium and pH were the most effective soil variables.
Combination of nifedipine and subtherapeutic dose of cyclosporin additively suppresses mononuclear cells activation of patients with rheumatoid arthritis and normal individuals via Ca2+–calcineurin–nuclear factor of activated T cells pathway
Authors: Lai N-S , Yu C-L , Yin W-Y , Yu H-C , Huang H-B , Tung C-H , Lu M-C
Published: January 2012

Abnormal Ca2+-mediated signalling contributes to the pathogenesis of rheumatoid arthritis (RA). However, the potential implication of calcium channel blocker in RA remained unknown. We hypothesized that nifedipine, an L-type calcium channel blocker, combined with a calcineurin inhibitor, could suppress T cell activation via targeting different level of the Ca2+ signalling pathway. The percentage of activated T cells and the apoptotic rate of mononuclear cells (MNCs) was measured by flow cytometry. The MNC viability, cytokine production, cytosolic Ca2+ level and activity of the nuclear factor of activated T cells (NFAT) were measured by enzyme-linked immunosorbent assay (ELISA). The NFAT-regulated gene expression, including interleukin (IL)-2, interferon (IFN)-γ and granulocyte–macrophage colony-stimulating factor (GM-CSF), was measured by real-time polymerase chain reaction (PCR). We found that the percentage of activated T cells in anti-CD3 + anti-CD28-activated MNC was higher in RA patients. High doses of nifedipine (50 µM) increased MNCs apoptosis, inhibited T cell activation and decreased T helper type 2 (Th1) (IFN-γ)/Th2 (IL-10) cytokine production in both groups. The Ca2+ influx was lower in anti-CD3 + anti-CD28-activated MNC from RA patients than healthy volunteers and suppressed by nifedipine. When combined with a subtherapeutic dose (50 ng/ml) of cyclosporin, 1 µM nifedipine suppressed the percentage of activated T cells in both groups. Moreover, this combination suppressed more IFN-γ secretion and NFAT-regulated gene (GM-CSF and IFN-γ) expression in RA-MNCs than normal MNCs via decreasing the activity of NFATc1. In conclusion, we found that L-type Ca2+ channel blockers and subtherapeutic doses of cyclosporin act additively to suppress the Ca2+-calcineurin-NFAT signalling pathway, leading to inhibition of T cell activity. We propose that this combination may become a potential treatment of RA.
Effect of light stress from phytoplankton on the relationship between aquatic vegetation and the propagule bank in shallow lakes
Authors: ARTHAUD FLORENT , MOUSSET MATHILDE , VALLOD DOMINIQUE , ROBIN JOËL , WEZEL ALEXANDER , BORNETTE GUDRUN
Published: January 2012

1. The way light stress controls the recruitment of aquatic plants (phanerogams and charophytes) is a key process controlling plant biodiversity, although still poorly understood. Our aim was to investigate how light stress induced by phytoplankton, that is, independent from the aquatic plants themselves, determines the recruitment and establishment of plant species from the propagule bank. The hypotheses were that an increase in light stress (i) decreases abundance and species richness both of established aquatic plants and of propagules in the bank and (ii) decreases the recruitment success of plants from this bank.

2. These hypotheses were tested in 25 shallow lakes representing a light stress gradient, by sampling propagule banks before the recruitment phase and when the lakes are devoid of actively growing plants (i.e. at the end of winter), established vegetation at the beginning of the summer and phytoplankton biomass (chlorophyll a) during the recruitment and establishment phase.

3. The phytoplankton biomass was negatively correlated with the richness and abundance of established vegetation but was not correlated with the propagule bank (neither species richness nor propagule abundance). The similarity between the propagule bank and established vegetation decreased significantly with increasing phytoplankton biomass.

4. The contrast in species composition between the vegetation and the propagule bank at the highest light stress suggests poor recruitment from the propagule bank but prompts questions about its origin. It could result from dispersal of propagules from neighbouring systems. Propagules could also originate from a persistent propagule bank formerly produced in the lake, suggesting strong year‐to‐year variation in light stress and, as a consequence, in recruitment and reproductive success of plants.
Differential regulation of acid sphingomyelinase in macrophages stimulated with oxidized low‐density lipoprotein (LDL) and oxidized LDL immune complexes: role in phagocytosis and cytokine release
Authors: Truman Jean‐Philip , Al Gadban Mohammed M. , Smith Kent J. , Jenkins Russell W. , Mayroo Nalini , Virella Gabriel , Lopes‐Virella Maria F. , Bielawska Alicja , Hannun Yusuf A. , Hammad Samar M.
Published: January 2012

Oxidized low‐density lipoprotein (oxLDL) and oxLDL‐containing immune complexes (oxLDL‐IC) contribute to the formation of lipid‐laden macrophages (foam cells). Fcγ receptors mediate uptake of oxLDL‐IC, whereas scavenger receptors internalize oxLDL. We have previously reported that oxLDL‐IC, but not free oxLDL, activate macrophages and prolong their survival. Sphingomyelin is a major constituent of cell membranes and lipoprotein particles and acid sphingomyelinase (ASMase) hydrolyses sphingomyelin to generate the bioactive lipid ceramide. ASMase exists in two forms: lysosomal (L‐ASMase) and secretory (S‐ASMase). In this study we examined whether oxLDL and oxLDL‐IC regulate ASMase differently, and whether ASMase mediates monocyte/macrophage activation and cytokine release. The oxLDL‐IC, but not oxLDL, induced early and consistent release of catalytically active S‐ASMase. The oxLDL‐IC also consistently stimulated L‐ASMase activity, whereas oxLDL induced a rapid transient increase in L‐ASMase activity before it steadily declined below baseline. Prolonged exposure to oxLDL increased L‐ASMase activity; however, activity remained significantly lower than that induced by oxLDL‐IC. Further studies were aimed at defining the function of the activated ASMase. In response to oxLDL‐IC, heat‐shock protein 70B’ (HSP70B’) was up‐regulated and localized with redistributed ASMase in the endosomal compartment outside the lysosome. Treatment with oxLDL‐IC induced the formation and release of HSP70‐containing and IL‐1β‐containing exosomes via an ASMase‐dependent mechanism. Taken together, the results suggest that oxLDL and oxLDL‐IC differentially regulate ASMase activity, and the pro‐inflammatory responses to oxLDL‐IC are mediated by prolonged activation of ASMase. These findings may contribute to increased understanding of mechanisms mediating macrophage involvement in atherosclerosis.
Towards a competency model for requirements analysts
Authors: Klendauer Ruth , Berkovich Marina , Gelvin Richard , Leimeister Jan Marco , Krcmar Helmut
Published: January 2012

Requirements engineering is a software development discipline, executed by requirements analysts (RAs), that includes requirements elicitation, analysis, specification and validation. Its successful outcome is very often essential to overall project success. However, there is a lack of systematically conducted empirical research on the competencies of RAs. This paper addressed this gap by conducting 64 interviews at eight major North American and European financial services companies. Our qualitative research design follows an interpretive approach and uses critical incident technique. We develop a competency model, which specifies 16 critical competencies, and integrates contextual and situational factors as well as results variables. ‘Consulting others’, ‘Testing assumptions and investigating’ and ‘Explaining concepts and opinions’ were the most frequently identified competencies. This indicates that for an effective analyst, close interaction and communication with customers is indeed crucial – but of equally importance is the critical questioning of the expressed needs. Surprisingly, applying specific tools and advanced techniques did not seem to play a significant role from the interviewees' perspective. This study contributes to theory as it is the first to elaborate a competency model for RAs. It also provides a foundation for the development of competency‐based training in companies and universities.
Forest productivity increases with evenness, species richness and trait variation: a global meta‐analysis
Authors: Zhang Yu , Chen Han Y. H. , Reich Peter B.
Published: January 2012

1. Although there is ample support for positive species richness–productivity relationships in planted grassland experiments, a recent 48‐site study found no diversity–productivity relationship (DPR) in herbaceous communities. Thus, debate persists about diversity effects in natural versus planted systems. Additionally, current knowledge is weak regarding the influence of evenness on the DPRs, how DPRs are affected by the variation in life‐history traits among constituent species in polycultures and how DPRs differ among biomes. The impacts of these factors on DPRs in forest ecosystems are even more poorly understood.

2. We performed a meta‐analysis of 54 studies to reconcile DPRs in forest ecosystems. We quantified the net diversity effect as log effect size [ln(ES)], the log ratio of the productivity in polycultures to the average of those in monocultures within the same type of mixture, site condition and stand age of each study. The first use of a boosted regression tree model in meta‐analysis, a useful method to partition the effects of multiple predictors rather than relying on vote‐counting of individual studies, unveiled the relative influences of individual predictors.

3. Global average ln(ES) was 0.2128, indicating 23.7% higher productivity in polycultures than monocultures. The final model explained 21% of the variation in ln(ES). The predictors that substantially accounted for the explained variation included evenness (34%), heterogeneity of shade tolerance (29%), richness (13%) and stand age (15%). In contrast, heterogeneity of nitrogen fixation and growth habits, biome and stand origin (naturally established versus planted) contributed negligibly (each ≤ 4%). Log effect size strongly increased with evenness from 0.6 to 1 and with richness from 2 to 6. Furthermore, it was higher with heterogeneity of shade tolerance and generally increased with stand age.

4. Synthesis.Our analysis is, to our knowledge, the first to demonstrate the critical role of species evenness, richness and the importance of contrasting traits in defining net diversity effects in forest polycultures. While testing the specific mechanisms is beyond the scope of our analysis, our results should motivate future studies to link richness, evenness, contrasting traits and life‐history stage to the mechanisms that are expected to produce positive net biodiversity effects such as niche differentiation, facilitation and reduced Janzen–Connell effects.
Which plant traits determine abundance under long‐term shifts in soil resource availability and grazing intensity?
Authors: Laliberté Etienne , Shipley Bill , Norton David A. , Scott David
Published: January 2012

1. Soil resource availability and disturbance are widely recognized as key drivers of plant community structure. However, the relative importance of different plant traits in determining species abundance following shifts in soil resource availability and disturbance remains little studied, particularly in long‐term experiments.

2. We studied trait‐based plant community assembly in a 27‐year grassland experiment where 25 plant species were sown into resident vegetation, after which annual manipulations of soil resource availability (five levels of superphosphate fertilizer; the highest level was also irrigated) and disturbance (three ‘mob‐grazed’ sheep grazing intensity levels: lax, moderate, hard) were applied. We used community assembly through trait selection (CATS) models based on entropy maximization to predict species relative abundances and to quantify the relative importance of each trait in determining abundance.

3. Plant species were primarily differentiated along a trade‐off axis corresponding to traits promoting rapid growth (e.g. high leaf [N] and specific leaf area [SLA]) vs. those promoting long leaf life span. Using 12 traits, the CATS model predicted >80% of the variation in the relative abundances of 51 species, suggesting that trait‐based filtering was important.

4. Species with leaf attributes that reduce nutrient losses held a long‐term advantage under the lowest soil resource availability, whereas those associated with a rapid growth rate became dominant under soil resource addition. Species with thinner leaves were also favoured under greater soil resource availability, which may reflect a strategy to maximize SLA without sacrificing leaf density and thus maintain leaf structural defences under grazing disturbance. Greater leaf [S] and the ability to symbiotically fix atmospheric N were favoured under greater soil resource availability. Greater plant height, thinner leaves and higher leaf [N] were favoured under lower grazing intensity.

5. Synthesis. Our results highlight the importance of species functional differences to understand how plant communities react to increases in soil resource availability and disturbance, two important and inseparable components of land‐use change in grasslands world‐wide.
Maintenance of tree phylogenetic diversity in a highly fragmented rain forest
Authors: Arroyo‐Rodríguez Víctor , Cavender‐Bares Jeannine , Escobar Federico , Melo Felipe P. L. , Tabarelli Marcelo , Santos Bráulio A.
Published: January 2012

1. Deforestation and forest fragmentation can drive species to local extinction, potentially changing the phylogenetic community structure and diversity of remaining assemblages. We tested this hypothesis analysing a large vegetation data set from a highly fragmented rain forest.

2. We assessed 9000 trees (both saplings and adults) from 268 species in 45 rain forest patches (ranging from < 1 to 700 ha) in three landscapes with different deforestation levels (4%, 11%, and 24% forest cover) in Los Tuxtlas, Mexico. We tested whether species density (i.e. number of species per unit area) and phylogenetic structure and diversity differed among landscapes, whether they were related to patch area, and whether the relationships differed among landscapes.

3. Overall, the observed differences in sapling and adult species densities across forest patches and landscapes (e.g. lower species densities in smaller patches) resulted in few and very weak changes in the phylogenetic community structure and diversity. Our results indicate that local extirpation of tree species may occur randomly or uniformly (but not in a clustered manner) throughout the phylogenetic tree, supporting the hypothesis of low phylogenetic conservatism of traits associated with vulnerability to forest fragmentation in the Neotropics.

4. Synthesis. This study indicates that in highly deforested and fragmented rain forests, the local extirpation of tree species does not occur across entire lineages. These novel and hopeful findings have direct implications for the ecology and conservation of fragmented rain forests. The maintenance of phylogenetic diversity in highly fragmented landscapes suggests that ecosystem function and stability may be maintained despite the loss of a number of tree species. We argue that in this unique Neotropical region, both large and small rain forest patches are critical for conserving regional tree evolutionary history.
Ultra‐low‐volume space sprays in mosquito control: a critical review
Authors: BONDS J. A. S.
Published: January 2012

The availability of tools to control mosquito (Diptera:Culicidae) vectors that transmit disease is often limited by a variety of economic, environmental and social issues. In emergency conditions (epidemics, hurricanes, floods etc.), the application of pesticides as space sprays (either by ground or air) is the common method of choice in order to rapidly limit adult local mosquito production in the affected area. Space spray application now employs ultra‐low‐volume technology for the control of adult mosquitoes. However, the use of space sprays often raises social and environmental concerns by the general public that is served.

This review will define and illustrate modern ultra‐low‐volume technology for the purpose of application as a space spray, as well as describing the engineering controls that have been developed to minimize the environmental impact. The primary social concern is validity and efficacy of application. To address this point, the review will attempt to synthesize the global literature to address the effectiveness of space sprays to significantly impact mosquito vectors in relation to human disease.
The re‐emergence of the bed bug as a nuisance pest: implications of resistance to the pyrethroid insecticides
Authors: DAVIES T. G. E. , FIELD L. M. , WILLIAMSON M. S.
Published: January 2012

A global resurgence of bed bugs (Hemiptera: Cimicidae) has led to renewed scientific interest in these insects. The current bed bug upsurge appears to have started almost synchronously in the late 1990s in Europe, the U.S.A. and Australia. Several factors have led to this situation, with resistance to applied insecticides making a significant contribution. With a growing number of insecticides (DDT, carbamates, organophosphates etc.) being no longer available as a result of regulatory restrictions, the mainstay chemistry used for bed bug control over the past few decades has been the pyrethroid insecticides. With reports of increasing tolerance to pyrethroids leading to control failures on the rise, containing and eradicating bed bugs is proving to be a difficult task. Consequently, several recent studies have focused on determining the mode of action of pyrethroid resistance in bed bug populations sourced from different locations. Correct identification of the factor(s) responsible for the increasing resistance is critical to the development of effective management strategies, which need to be based, wherever possible, on firm scientific evidence. Here we review the literature on this topic, highlighting the mechanisms thought to be involved and the problems currently faced by pest control professionals in dealing with a developing pandemic.
Learning from clinical work: the roles of learning cues and credibility judgements
Authors: Watling Christopher , Driessen Erik , van der Vleuten Cees P M , Lingard Lorelei
Published: January 2012

Medical Education 2012:

46

: 192–200

Context:  How learners interpret their clinical experiences to create meaningful learning has not been well studied. We explored experiences considered by doctors to be influential in their learning in order to better understand this process.

Methods:  Using a grounded theory approach, we interviewed 22 academic doctors who had been in practice for ≤ 5 years. Participants were asked to reflect on experiences they considered to have been influential during their training. Constant comparative analysis for emerging themes was conducted iteratively with data collection.

Results:  A model of clinical learning emerged in which the clinical work itself is central. As they observe and participate in clinical work, learners can attend to a variety of sources of information that facilitate the interpretation of the experience and the construction of knowledge from it. These ‘learning cues’ include feedback, role models, clinical outcomes, patient or family responses, and comparisons with peers. The integration of a cue depends on the learner’s judgement of its credibility. Certain cues, such as clinical outcomes or feedback from patients, are seen as innately credible, whereas other cues, particularly feedback from supervisors, are subjected to critical judgement.

Conclusions:  Learners make complex judgements regarding the credibility of information about clinical performance. Credibility judgements influence the learning that arises from the clinical experience. Further understanding of how such judgements are made could guide educators in providing credible information to learners.
Faculty staff perceptions of feedback to residents after direct observation of clinical skills
Authors: Kogan Jennifer R , Conforti Lisa N , Bernabeo Elizabeth C , Durning Steven J , Hauer Karen E , Holmboe Eric S
Published: January 2012

Medical Education 2012:

46

: 201–215

Context  Performance‐based workplace assessments are increasingly important in clinical training. Given the inaccuracy of self‐assessment, the provision of external feedback to residents about their clinical skills is necessary for the development of expertise. However, little is known about the processes used by faculty members in giving feedback to residents after observing them with patients. This study explores the factors that underpin faculty members’ decisions regarding the feedback they give to residents after directly observing them with patients and the factors that influence how feedback is delivered.

Methods  In 2009, 44 general internal medicine faculty staff responsible for out‐patient resident teaching from 16 internal medicine residency programmes watched four videotaped scenarios and two live scenarios of standardised residents (SRs) with standardised patients and rated the SRs using the mini‐clinical evaluation exercise (mini‐CEX) format. Faculty staff also provided feedback to the SRs after the live encounters. After each encounter, faculty staff were individually interviewed using a semi‐structured interview. Interviews were videotaped, transcribed and analysed using grounded theory methods.

Results  Two broad themes were identified in faculty members’ descriptions of the feedback process: variability in feedback techniques, and the factors that influence how faculty staff think and feel about delivering feedback. Multiple approaches to feedback delivery were observed. Faculty members’ tensions in balancing positive and negative feedback, their own perceived self‐efficacy, their perceptions of the resident’s insight, receptivity, skill and potential, the faculty member–resident relationship and contextual factors impacted the feedback process.

Conclusions  The provision of feedback by faculty staff to residents after observing resident–patient interactions is a complex and dynamic process and is influenced by many factors. Understanding these cognitive and affective factors may provide insight into potential new approaches to faculty development to improve faculty staff’s feedback skills and the effectiveness of their feedback.
Defying stereotypes: the elusive search for a universal model of LysR‐type regulation
Authors: Momany Cory , Neidle Ellen L.
Published: January 2012

LysR‐type transcriptional regulators (LTTRs) compose the largest family of homologous regulators in bacteria. Considering their prevalence, it is not surprising that LTTRs control diverse metabolic functions. Arguably, the most unexpected aspect of LTTRs is the paucity of available structural information. Solubility issues are notoriously problematic, and structural studies have only recently begun to flourish. In this issue of Molecular Microbiology, Taylor et al. (2012) present the structure of AphB, a LysR‐type regulator of virulence in Vibrio cholerae. This contribution adds significantly to the group of known full‐length atomic LTTR structures, which remains small. Importantly, this report also describes an active‐form variant. Small conformational changes in the effector‐binding domain translate to global reorganization of the DNA‐binding domain. Emerging from these results is a model of theme‐and‐variation among LTTRs rather than a unified regulatory scheme. Despite common structural folds, LTTRs exhibit differences in oligomerization, promoter recognition and communication with RNA polymerase. Such variation mirrors the diversity in sequence and function associated with members of this very large family.
Decreased myosin phosphatase target subunit 1(MYPT1) phosphorylation via attenuated rho kinase and zipper‐interacting kinase activities in edematous intestinal smooth muscle
Authors: Chu J. , Miller C. T. , Kislitsyna K. , Laine G. A. , Stewart R. H. , Cox C. S. , Uray K. S.
Published: January 2012

Background  Intestinal edema development after trauma resuscitation inhibits intestinal motility which results in ileus, preventing enteral feeding and compromising patient outcome. We have shown previously that decreased intestinal motility is associated with decreased smooth muscle myosin light chain (MLC) phosphorylation. The purpose of the present study was to investigate the mechanism of edema‐induced decreases in MLC in a rodent model of intestinal edema.

Methods  Intestinal edema was induced by a combination of resuscitation fluid administration and mesenteric venous hypertension. Sham operated animals served as controls. Contractile activity and alterations in the regulation of MLC including the regulation of MLC kinase (MLCK) and MLC phosphatase (MLCP) were measured.

Key Results  Contraction amplitude and basal tone were significantly decreased in edematous intestinal smooth muscle compared with non‐edematous tissue. Calcium sensitivity was also decreased in edematous tissue compared with non‐edematous intestinal smooth muscle. Although inhibition of MLCK decreased contractile activity significantly less in edematous tissue compared with non‐edematous tissue, MLCK activity in tissue lysates was not significantly different. Phosphorylation of MYPT was significantly lower in edematous tissue compared with non‐edematous tissue. In addition, activities of both rho kinase and zipper‐interacting kinase were significantly lower in edematous tissue.

Conclusions & Inferences  We conclude from these data that interstitial intestinal edema inhibits MLC phosphorylation predominantly by decreasing inhibitory phosphorylation of the MLC targeting subunit (MYPT1) of MLC phosphatase via decreased ROCK and ZIPK activities, resulting in more MLC phosphatase activity.
Topographic and manometric characterization of the recto‐anal inhibitory reflex
Authors: Cheeney G. , Nguyen M. , Valestin J. , Rao S. S. C.
Published: January 2012

Background  Recto‐anal inhibitory reflex (RAIR) is an integral part of normal defecation. The physiologic characteristics of RAIR along anal length and anterior‐posterior axis are unknown. The aim of this study was to perform topographic and vector‐graphic evaluation of RAIR along anal canal using high definition manometry (HDM), and examine the role of various muscle components.

Methods  Anorectal topography was assessed in 10 healthy volunteers using HDM probe with 256 sensors. Recto‐anal inhibitory reflex data were analyzed every mm along the length of anal canal for topographic, baseline, residual, and plateau pressures during five mean volumes of balloon inflation (15 cc, 40 cc, 71 cc, 101 cc, 177 cc), and in 3D by dividing anal canal into 4 × 2.1 mm grids.

Key Results  Relaxation pressure progressively increases along anal canal with increasing balloon volume up to 71 cc and thereafter plateaus. In 3D, RAIR is maximally seen at the middle and upper portions of anal canal (levels 1.2–3.2 cm) and posteriorly. Peak residual pressure was seen at proximal anal canal.

Conclusions & Inferences  Recto‐anal inhibitory reflex is characterized by differential anal relaxation along anterior–posterior axis, longitudinally along the length of anal canal, and it depends on the rectal distention volume. It is maximally seen at internal anal sphincter pressure zone. Multidimensional analyses indicate that external anal sphincter provides bulk of anal residual pressure. Our findings emphasize importance of sensor location and orientation; as anterior and more distal location may miss RAIR.
Plasticity of mouse enteric synapses mediated through endocannabinoid and purinergic signaling
Authors: Hons I. M. , Storr M. A. , Mackie K. , Lutz B. , Pittman Q. J. , Mawe G. M. , Sharkey K. A.
Published: January 2012

Background  The enteric nervous system (ENS) possesses extensive synaptic connections which integrate information and provide appropriate outputs to coordinate the activity of the gastrointestinal tract. The regulation of enteric synapses is not well understood. Cannabinoid (CB)1 receptors inhibit the release of acetylcholine (ACh) in the ENS, but their role in the synapse is not understood. We tested the hypothesis that enteric CB1 receptors provide inhibitory control of excitatory neurotransmission in the ENS.

Methods  Intracellular microelectrode recordings were obtained from mouse myenteric plexus neurons. Interganglionic fibers were stimulated with a concentric stimulating electrode to elicit synaptic events on to the recorded neuron. Differences between spontaneous and evoked fast synaptic transmission was examined within preparations from CB1 deficient mice (CB1−/−) and wild‐type (WT) littermate controls.

Key Results  Cannabinoid receptors were colocalized on terminals expressing the vesicular ACh transporter and the synaptic protein synaptotagmin. A greater proportion of CB1−/− neurons received spontaneous fast excitatory postsynaptic potentials than neurons from WT preparations. The CB1 agonist WIN55,212 depressed WT synapses without any effect on CB1−/− synapses. Synaptic activity in response to depolarization was markedly enhanced at CB1−/− synapses and after treatment with a CB1 antagonist in WT preparations. Activity‐dependent liberation of a retrograde purine messenger was demonstrated to facilitate synaptic transmission in CB1−/− mice.

Conclusions & Inferences  Cannabinoid receptors inhibit transmitter release at enteric synapses and depress synaptic strength basally and in an activity‐dependent manner. These actions help explain accelerated intestinal transit observed in the absence of CB1 receptors.
Growth‐dependent chemical and mechanical properties of cuticular membranes from leaves of Sonneratia alba
Authors: TAKAHASHI YUKI , TSUBAKI SHUNTARO , SAKAMOTO MASAHIRO , WATANABE SHIN , AZUMA JUN‐ICHI
Published: January 2012

Chemical and mechanical properties of the leaf cuticular membranes (CMs) of a mangrove, Sonneratia alba J. Smith, were analysed at various leaf development stages to evaluate their tolerance to environmental stress. Our analyses demonstrate that the CMs from leaves of S. alba at different growth stages are generally rich in wax (21.5–25.7%) and cutin (52.4–63.4%) which rapidly accumulate at the early stages of leaf growth, while cutan (4.3–10.3%) and polysaccharide (2.3–7.7%) continuously accumulate throughout growth. Immature CMs are physically weak and highly viscoelastic. However, CMs become strengthened and stiffened during leaf expansion and maturation (by factors of about 1.5 and 2.4, respectively) while their flexibility decreases (68–83% decrease). Finally, the CMs lose their strength at the senescent stage (30–43% decreasement). Correlation analysis between chemical composition and mechanical properties revealed that the cutin matrix is mainly responsible for the high viscoelastic properties of CMs, while wax, cutan and polysaccharide contributed to their elasticity. Wax also affected the strength of the CMs, whereas cutan and polysaccharide showed rigidizing effect. Rapid accumulation of wax and cutin in the CMs after bud burst followed by the mechanical supports of cutan and polysaccharide in an isolateral manner contributed to the remarkable environmental tolerance of S. alba.
DNA‐PKcs Interacts with Aire and Regulates the Expression of Toll‐Like Receptors in RAW264.7 Cells
Authors: Wu J. , Zhu W. , Fu H. , Zhang Y. , Sun J. , Yang W. , Li Y.
Published: January 2012

The autoimmune regulator (Aire) is a key mediator of the central tolerance for peripheral tissue self‐antigen (PTAs) and is involved in the transcriptional control of many antigens in thymic medullary epithelial cells (mTECs). However, the function of Aire in peripheral lymphoid tissues and haematopoietic cells, particularly in monocytes and macrophages, remains poorly understood. We previously found that the expression of Toll‐like receptor (TLR) 1, TLR3 and TLR8 was notably upregulated in pEGFPC1/Aire stably transfected RAW264.7 (GFP‐Aire/RAW) cells, while the expressions of other TLRs were not significantly changed. The mechanism by which Aire affects TLR1, TLR3 and TLR8 expression is not clear. Interactions with other proteins, such as DNA‐dependent protein kinase (DNA‐PK), are crucial for regulating the transcriptional activity of Aire. In this study, we found that Aire and DNA‐PK catalytic subunit (DNA‐PKcs) were co‐located in the nucleus of GFP‐Aire/RAW cells, and they interact with each other. Small interfering RNA knock‐down of DNA‐PKcs in these cells decreased the expression of TLR1, TLR3 and TLR8, but no change was observed in pEGFPC1 stably transfected RAW264.7 (GFP/RAW) cells. We did not observe any change in the expressions of other TLRs after DNA‐PKcs knock‐down in GFP‐Aire/RAW or GFP/RAW cells. A similar observation has been made in pEGFPC1/Aire or pEGFPC1 transiently transfected primary peritoneal macrophages. Using a luciferase activity assay, we found the that the transcriptional activity of TLR1, TLR3 and TLR8 promoters was also decreased after knock‐down of DNA‐PKcs in GFP‐Aire/RAW cells. In conclusion, our results suggest that DNA‐PKcs may interact with Aire to promote the expression of TLRs in RAW264.7 cells.
Cover crops of oats, stooling rye and three annual ryegrass cultivars influence maize and Cyperus esculentus growth
Authors: BEZUIDENHOUT S R , REINHARDT C F , WHITWELL M I
Published: January 2012

Bezuidenhout SR, Reinhardt CF & Whitwell MI (2012). Cover crops of oats, stooling rye and three annual ryegrass cultivars influence maize and Cyperus esculentus growth. Weed Research 52, 153–160.

No information is available on the effect of cover crops on weed growth in maize production in KwaZulu‐Natal, South Africa. In a field experiment, the influence of two preceding cover crops, stooling rye and annual ryegrass, on the growth of maize and the weed Cyperus esculentus were compared with herbicides and weed control by hoeing. Maize emergence and early growth were delayed in the presence of physical residues of both cover crop species, especially annual ryegrass. Growth of C. esculentus was significantly inhibited in the inter‐row maize planting lines by the cover crops for the first 16 days after maize emergence, but this effect had diminished by day 28. In a pot experiment, the influence of the same two cover crops on maize and C. esculentus growth was evaluated together with oats and two additional annual ryegrass cultivars. Here, the growth of maize and C. esculentus were suppressed, especially by the root residues of the annual ryegrass, in particular the cultivar Midmar. Chemical analysis of the leachate of the root residues indicated the presence of phenolic acids and benzoxazolin‐2(3H)‐one. To achieve effective weed control, a weed management strategy combining the mulch retained on the soil surface, with a possible reduction in the type and amount of herbicide, should be implemented.
Red cell microparticle enumeration: validation of a flow cytometric approach
Authors: Xiong Z. , Oriss T. B. , Cavaretta J. P. , Rosengart M. R. , Lee J. S.
Published: January 2012

Background and Objectives  There is growing interest in the clinical application of red blood cell (RBC) microparticle (MP) enumeration as they have been postulated to be effectors of coagulation and inflammation following transfusion and in sickle cell disease. No uniform approach in MP enumeration exists and a key limitation is the lack of an internal validation process. We present and validate a flow cytometric approach where an internal standard is utilized.

Materials and Methods  Glycophorin A+ Annexin V+ events were enumerated using MPs isolated from RBC units or plasma samples obtained from volunteers. A mixture of absolute counting (7·6 μm) and calibration beads (0·5, 0·9 and 3 μm) at a fixed ratio was added to each sample.

Results  RBC MPs were initially selected based upon a fluorescence threshold, and the 0·5‐ and 0·9‐μm beads defined the upper and lower light scatter distribution of MPs. The ratio of 7·6:3‐μm bead events was used as an internal standard to validate the precision of MP enumeration across samples (coefficient of variation = 2·5–7·2%) and remained constant in both platelet‐rich plasma (PRP) and platelet‐free plasma (PFP). RBC MP counts increased in both PRP and PFP obtained from whole blood stimulated with ionophore and increasing calcium concentrations, with PRP showing higher MP counts than PFP at every concentration studied.

Conclusion  This method is a useful strategy to detect RBC MP counts across bio‐samples provided that the flow cytometer can reliably discriminate the size of the calibration beads.
Induced out‐of‐plane mode at the tip of blunt lateral notches and holes under in‐plane shear loading
Authors: BERTO F. , LAZZARIN P. , KOTOUSOV A. , POOK L. P.
Published: January 2012

As it is well known the Poisson's effect in a cracked plate subjected to anti‐symmetric plane loading leads to the generation of a coupled out‐of‐plane singular mode. Recent theoretical and numerical analyses have shown that this effect is present also in plates weakened by sharp V‐notches and might play a role in failure initiation phenomena of notched plates subjected to Mode II loading, especially in the presence of a large notch opening angle.

Dealing with blunt notches with a large notch radius, and not just with sharp notches, the presence or not of an out‐of‐plane mode does not appear to have been systematically investigated in the past. The main aim of this work is to confirm the existence of the stress field associated with the out‐of‐plane mode (Mode O) and to describe its main features in the presence of a notch radius significantly different from zero. The analyses include U‐notches, as well as circular and elliptic holes. The strain energy density in a 3D control volume is utilized to identify the most critical zone (with respect to failure initiation) through the plate thickness at the notch tip.
Inputs from the basolateral amygdala to the nucleus accumbens shell control opiate reward magnitude via differential dopamine D1 or D2 receptor transmission
Authors: Lintas Alessandra , Chi Ning , Lauzon Nicole M. , Bishop Stephanie F. , Sun Ninglei , Tan Huibing , Laviolette Steven R.
Published: January 2012

The basolateral amygdala (BLA), ventral tegmental area and nucleus accumbens (NAc) form a functionally connected neural circuit involved in the processing of opiate‐related reward and memory. Dopamine (DA) projections from the ventral tegmental area to the BLA modulate associative plasticity mechanisms within the BLA. However, the role of DA receptor signaling in the BLA and its functional outputs to the NAc during opiate reward processing is not currently understood. Using an unbiased place conditioning procedure, we measured the rewarding effects of morphine following intra‐BLA microinfusions of specific DA D1 or D2 receptor agonists in either opiate‐naive or opiate‐dependent/withdrawn rats. Activation of intra‐BLA D1 receptors strongly potentiated the behaviorally rewarding effects of opiates, only in the opiate‐naive state. However, once opiate dependence and withdrawal occurred, the intra‐BLA DA‐mediated potentiation of opiate reward salience switched to a D2 receptor‐dependent substrate. We next performed single‐unit, in‐vivo extracellular neuronal recordings in the NAc shell (NA shell), to determine if intra‐BLA D1/D2 receptor activation may modulate the NA shell neuronal response patterns to morphine. Consistent with our behavioral results, intra‐BLA D1 or D2 receptor activation potentiated NAc ‘shell’ (NA shell) neuronal responses to sub‐reward threshold opiate administration, following the same functional boundary between the opiate‐naive and opiate‐dependent/withdrawn states. Finally, blockade of N‐methyl‐d‐aspartate transmission within the NA shell blocked intra‐BLA DA D1 or D2 receptor‐mediated opiate reward potentiation. Our findings demonstrate a novel and functional DA D1/D2 receptor‐mediated opiate reward memory switch within the BLA→NA shell circuit that controls opiate reward magnitude as a function of opiate exposure state.