Phagocytosis of bacteria by olfactory ensheathing cells and Schwann cells

Opportunistic bacterial infections of the nasal cavity could potentially lead to infection of the brain if the olfactory or trigeminal nerves are colonised. The olfactory nerve may be a more susceptible route because primary olfactory neurons are in direct contact with the external environment. Peripheral glia are known to be able to phagocytose some species of bacteria and may therefore provide a defence mechanism against bacterial infection. As the nasal cavity is frequently exposed to bacterial infections, we hypothesised that the olfactory and trigeminal nerves within the nasal cavity could be subjected to bacterial colonisation and that the olfactory ensheathing cells and Schwann cells may be involved in responding to the bacterial invasion. We have examined the ability of mouse OECs and Schwann cells from the trigeminal nerve and dorsal root ganglia to phagocytose Escherichia coli and Burkholderia thailandensis in vitro. We found that all three sources of glia were equally able to phagocytose E. coli with 75-85% of glia having phagocytosed bacteria within 24h. We also show that human OECs phagocytosed E. coli. In contrast, the mouse OECs and Schwann cells had little capacity to phagocytose B. thailandensis. Thus subtypes of peripheral glia have similar capacities for phagocytosis of bacteria but show selective capacity for the two different species of bacteria that were examined. These results have implications for the understanding of the mechanisms of bacterial infections as well as for the use of glia for neural repair therapies.

Turning points in narratives of research design : research innovation stimulating unique responses to existing challenges for beginning rural teachers

This paper explores methodological turning points in researching narratives of early career resilience mediated by the complexities of remote teaching. Innovative, flexible and discursive research design facilitated exploration of emerging narratives using digital technologies. Data were regularly interrogated with participant-researchers to reveal the undercurrents of imbued meaning. Dialogue with participant-researchers enhanced interpretations of data plots and text-based explanations of narrative turning points, providing valuable insights throughout analysis. Reflections on the affordances and tensions in this process illustrate the significance of innovation but also the complexities associated with online collaboration. Consequently, empowering the participant-researchers throughout the life of the research was critical in understanding their narratives of teaching.

Evaluation of BMP-2 gene-activated muscle grafts for cranial defect repair

Large, osseous, segmental defects heal poorly. Muscle has a propensity to form bone when exposed to an osteogenic stimulus such as that provided by transfer and expression of cDNA encoding bone morphogenetic protein-2 (BMP-2). The present study evaluated the ability of genetically modified, autologous muscle to heal large cranial defects in rats. Autologous grafts (8 mm � 2 mm) were punched from the biceps femoris muscle and transduced intraoperatively with recombinant adenovirus vector containing human BMP-2 or green fluorescent protein cDNA. While the muscle biopsies were incubating with the vector, a central parietal 8 mm defect was surgically created in the calvarium of the same animal. The gene-activated muscle graft was then implanted into the cranial defect. After 8 weeks, crania were examined radiographically, histologically, and by micro-computed tomography and dual energy X-ray absorptiometry. Although none of the defects were completely healed in this time, muscle grafts expressing BMP-2 deposited more than twice as much new bone as controls. Histology confirmed the anatomical integrity of the newly formed bone, which was comparable in thickness and mineral density to the original cranial bone. This study confirms the in vivo osteogenic properties of genetically modified muscle and suggests novel strategies for healing bone. � 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1095–1102, 2012

Expression of β1 integrin in laminin-adhesion-selected human colon cancer cell lines of varying tumorigenicity

Laminin has been shown to promote the malignant phenotype and the expression of certain laminin receptors has been correlated with the malignant character of the tumors. Here new cell lines were isolated from a human colon cancer cell line (LCC-C1) based on their adhesiveness to laminin. The laminin-adherent subclone formed large tumors in nude mice, whereas the laminin-nonadherent subclone failed to form sizable tumors. Only the laminin-adherent subclone adhered to laminin and invaded through Matrigel-coated filters. The adhesive and invasive ability of the cells was almost completely blocked by low concentrations (1.0 μg/ml) of anti-β1 integrin antibody. The amounts of total cellular β1 integrin protein were similar in the two subclones when compared by Western blot, and the mRNA levels also did not differ. The localization of β1 integrin laminin receptor varied in the two subclones; the laminin-adherent subclone showed a linear distribution along the cell-cell junctions, while the laminin-nonadherent subclone did not stain between the cells. Using laminin-Sepharose affinity chromatography, more β1 integrin was obtained from the laminin-adherent subclone. These findings suggest that alterations in the affinity of β1 integrin for laminin and in its membrane distribution might be involved in the increased tumorigenicity observed in colon cancer cells.

Validation of a framework for measuring hospital disaster resilience using factor analysis

Hospital disaster resilience can be defined as “the ability of hospitals to resist, absorb, and respond to the shock of disasters while maintaining and surging essential health services, and then to recover to its original state or adapt to a new one.” This article aims to provide a framework which can be used to comprehensively measure hospital disaster resilience. An evaluation framework for assessing hospital resilience was initially proposed through a systematic literature review and Modified-Delphi consultation. Eight key domains were identified: hospital safety, command, communication and cooperation system, disaster plan, resource stockpile, staff capability, disaster training and drills, emergency services and surge capability, and recovery and adaptation. The data for this study were collected from 41 tertiary hospitals in Shandong Province in China, using a specially designed questionnaire. Factor analysis was conducted to determine the underpinning structure of the framework. It identified a four-factor structure of hospital resilience, namely, emergency medical response capability (F1), disaster management mechanisms (F2), hospital infrastructural safety (F3), and disaster resources (F4). These factors displayed good internal consistency. The overall level of hospital disaster resilience (F) was calculated using the scoring model: F = 0.615F1 + 0.202F2 + 0.103F3 + 0.080F4. This validated framework provides a new way to operationalise the concept of hospital resilience, and it is also a foundation for the further development of the measurement instrument in future studies.

Enhancement of RAD51 recombinase activity by the tumor suppressor PALB2

Homologous recombination mediated by RAD51 recombinase helps eliminate chromosomal lesions, such as DNA double-strand breaks induced by radiation or arising from injured DNA replication forks. The tumor suppressors BRCA2 and PALB2 act together to deliver RAD51 to chromosomal lesions to initiate repair. Here we document a new function of PALB2: to enhance RAD51's ability to form the D loop. We show that PALB2 binds DNA and physically interacts with RAD51. Notably, although PALB2 alone stimulates D-loop formation, it has a cooperative effect with RAD51AP1, an enhancer of RAD51. This stimulation stems from the ability of PALB2 to function with RAD51 and RAD51AP1 to assemble the synaptic complex. Our results demonstrate the multifaceted role of PALB2 in chromosome damage repair. Because PALB2 mutations can cause cancer or Fanconi anemia, our findings shed light on the mechanism of tumor suppression in humans.

Molecular basis for enhancement of the meiotic DMC1 recombinase by RAD51 associated protein 1 (RAD51AP1)

Homologous recombination is needed for meiotic chromosome segregation, genome maintenance, and tumor suppression. RAD51AP1 (RAD51 associated protein 1) has been shown to interact with and enhance the recombinase activity of RAD51. Accordingly, genetic ablation of RAD51AP1 leads to enhanced sensitivity to and also chromosome aberrations upon DNA damage, demonstrating a role for RAD51AP1 in mitotic homologous recombination. Here we show physical association of RAD51AP1 with the meiosis-specific recombinase DMC1 and a stimulatory effect of RAD51AP1 on the DMC1-mediated D-loop reaction. Mechanistic studies have revealed that RAD51AP1 enhances the ability of the DMC1 presynaptic filament to capture the duplex-DNA partner and to assemble the synaptic complex, in which the recombining DNA strands are homologously aligned. We also provide evidence that functional cooperation is dependent on complex formation between DMC1 and RAD51AP1 and that distinct epitopes in RAD51AP1 mediate interactions with RAD51 and DMC1. Finally, we show that RAD51AP1 is expressed in mouse testes, and that RAD51AP1 foci colocalize with a subset of DMC1 foci in spermatocytes. These results suggest that RAD51AP1 also serves an important role in meiotic homologous recombination.

A variant of the breast cancer type 2 susceptibility protein (BRC) repeat is essential for the RECQL5 Helicase to interact with RAD51 Recombinase for genome stabilization

The BRC repeat is a structural motif in the tumor suppressor BRCA2 (breast cancer type 2 susceptibility protein), which promotes homologous recombination (HR) by regulating RAD51 recombinase activity. To date, the BRC repeat has not been observed in other proteins, so that its role in HR is inferred only in the context of BRCA2. Here, we identified a BRC repeat variant, named BRCv, in the RECQL5 helicase, which possesses anti-recombinase activity in vitro and suppresses HR and promotes cellular resistance to camptothecin-induced replication stress in vivo. RECQL5-BRCv interacted with RAD51 through two conserved motifs similar to those in the BRCA2-BRC repeat. Mutations of either motif compromised functions of RECQL5, including association with RAD51, inhibition of RAD51-mediated D-loop formation, suppression of sister chromatid exchange, and resistance to camptothecin-induced replication stress. Potential BRCvs were also found in other HR regulatory proteins, including Srs2 and Sgs1, which possess anti-recombinase activities similar to that of RECQL5. A point mutation in the predicted Srs2-BRCv disrupted the ability of the protein to bind RAD51 and to inhibit D-loop formation. Thus, BRC is a common RAD51 interaction module that can be utilized by different proteins to either promote HR, as in the case of BRCA2, or to suppress HR, as in RECQL5.

A biomechanical analysis of growing rods used in the management of early onset scoliosis

INTRODUCTION Managing spinal deformities in young children is challenging, particularly early-onset scoliosis (EOS). Any progressive spinal deformity particularly in early life presents significant health risks for the child and a challenge for the treating surgeon. Surgical intervention is often required if EOS has been unresponsive to conservative treatment particularly with rapidly progressive curves. An emerging treatment option particularly for EOS is fusionless scoliosis surgery. Similar to bracing this surgical option potentially harnesses growth, motion and function of the spine along with correcting spinal deformity. Dual growing rods is one such fusionless treatment, which aims to modulate growth of the vertebrae. The aim of this study was to ascertain the extent to which semi-constrained growing rods (Medtronic, Memphis, TN) with a telescopic sleeve component, reduce rotational constraint on the spine compared with standard rigid rods and hence potentially provide a more physiological mechanical environment for the growing spine. METHODS Six 40-60kg English Large White porcine spines served as a model for the paediatric human spine. Each spine was dissected into 7 level thoracolumbar multi-segment unit (MSU) spines, removing all non-ligamentous soft tissues. Appropriately sized semi-constrained growing rods and rigid rods were secured by multi-axial screws (Medtronic) prior to testing in alternating sequences for each spine. Pure nondestructive moments of +/4Nm at a constant rotation rate of 8deg/s was applied to the mounted MSU spines. Displacement of each level was captured using an Optotrak (Northern Digital Inc, Waterloo, ON). The range of motion (ROM), neutral zone (NZ) size and stiffness (Nm/deg) were calculated from the Instron load-displacement data and intervertebral ROM was calculated through a MATLAB algorithm from Optotrak data. RESULTS Irrespective of sequence order rigid rods significantly reduced the total ROM (deg) than compared to semi-constrained rods (p<0.05) and resulted in a significantly stiffer (Nm/deg) spine for both left and right axial rotation testing (p<0.05). Analysing the intervertebral motion within the instrumented levels, rigid rods showed reduced ROM (Deg) than compared to semi-constrained growing rods and the un-instrumented (UN-IN) test sequences. CONCLUSION The semi-constrained growing rods maintained rotation similar to UN-IN spines while the rigid rods showed significantly reduced axial rotation across all instrumented levels. Clinically the effect of semi-constrained growing rods evaluated in this study is that they will allow growth via the telescopic rod components while maintaining the axial rotation ability of the spine, which may also reduce the occurrence of the crankshaft phenomenon.

Achieving superior innovation-based performance outcomes in SMEs through innovation resource–capability complementarity

Firms are increasingly identifying new avenues to enhance their market position. One such effort involves the firms' ability to continuously learn. Learning has the capacity to enable firms to develop and implement more efficient and effective innovation-focused strategies, resulting in the ability to develop and deliver more products in a timelier manner. This study tests the relationship between innovation resource–capability complementarity and innovation-based performance. This study further elaborates that while innovation resource–capability complementarity drives innovation-based performance; their relationship will be enhanced via the firms' possession of superior learning capability. The findings show a significant effect of innovation resource–capability complementarity on innovation-based performance. The results also show that firms that possess superior learning capability are willing to question their operational processes and routines and make adjustments following the feedback obtained from customers and channels; thereby enhancing their abilities to develop more new products and increase their speed in delivering products to the customers.

Molecular analysis of the acinetobacter baumannii biofilm-associated protein

Acinetobacter baumannii is a multidrug-resistant pathogen associated with hospital outbreaks of infection across the globe, particularly in the intensive care unit. The ability of A. baumannii to survive in the hospital environment for long periods is linked to antibiotic resistance and its capacity to form biofilms. Here we studied the prevalence, expression, and function of the A. baumannii biofilm-associated protein (Bap) in 24 carbapenem-resistant A. baumannii ST92 strains isolated from a single institution over a 10-year period. The bap gene was highly prevalent, with 22/24 strains being positive for bap by PCR. Partial sequencing of bap was performed on the index case strain MS1968 and revealed it to be a large and highly repetitive gene approximately 16 kb in size. Phylogenetic analysis employing a 1,948-amino-acid region corresponding to the C terminus of Bap showed that BapMS1968 clusters with Bap sequences from clonal complex 2 (CC2) strains ACICU, TCDC-AB0715, and 1656-2 and is distinct from Bap in CC1 strains. By using overlapping PCR, the bapMS1968 gene was cloned, and its expression in a recombinant Escherichia coli strain resulted in increased biofilm formation. A Bap-specific antibody was generated, and Western blot analysis showed that the majority of A. baumannii strains expressed an ∼200-kDa Bap protein. Further analysis of three Bap-positive A. baumannii strains demonstrated that Bap is expressed at the cell surface and is associated with biofilm formation. Finally, biofilm formation by these Bap-positive strains could be inhibited by affinity-purified Bap antibodies, demonstrating the direct contribution of Bap to biofilm growth by A. baumannii clinical isolates.

Functional heterogeneity of the UpaH autotransporter protein from Uropathogenic Escherichia coli

Uropathogenic Escherichia coli (UPEC) is responsible for the majority of urinary tract infections (UTI). To cause a UTI, UPEC must adhere to the epithelial cells of the urinary tract and overcome the shear flow forces of urine. This function is mediated primarily by fimbrial adhesins, which mediate specific attachment to host cell receptors. Another group of adhesins that contributes to UPEC-mediated UTI is autotransporter (AT) proteins. AT proteins possess a range of virulence properties, such as adherence, aggregation, invasion, and biofilm formation. One recently characterized AT protein of UPEC is UpaH, a large adhesin-involved-in-diffuse-adherence (AIDA-I)-type AT protein that contributes to biofilm formation and bladder colonization. In this study we characterized a series of naturally occurring variants of UpaH. We demonstrate that extensive sequence variation exists within the passenger-encoding domain of UpaH variants from different UPEC strains. This sequence variation is associated with functional heterogeneity with respect to the ability of UpaH to mediate biofilm formation. In contrast, all of the UpaH variants examined retained a conserved ability to mediate binding to extracellular matrix (ECM) proteins. Bioinformatic analysis of the UpaH passenger domain identified a conserved region (UpaHCR) and a hydrophobic region (UpaHHR). Deletion of these domains reduced biofilm formation but not the binding to ECM proteins. Despite variation in the upaH sequence, the transcription of upaH was repressed by a conserved mechanism involving the global regulator H-NS, and mutation of the hns gene relieved this repression. Overall, our findings shed new light on the regulation and functions of the UpaH AT protein.

Virulence properties of asymptomatic bacteriuria Escherichia coli

In asymptomatic bacteriuria (ABU), bacteria colonize the urinary tract without provoking symptoms. Here, we compared the virulence properties of a collection of ABU Escherichia coli strains to cystitis and pyelonephritis strains. Specific urinary tract infection (UTI)-associated virulence genes, hemagglutination characteristics, siderophore production, hemolysis, biofilm formation, and the ability of strains to adhere to and induce cytokine responses in epithelial cells were analyzed. ABU strains were phylogenetically related to strains that cause symptomatic UTI. However, the virulence properties of the ABU strains were variable and dependent on a combination of genotypic and phenotypic factors. Most ABU strains adhered poorly to epithelial cells; however, we also identified a subgroup of strongly adherent strains that were unable to stimulate an epithelial cell IL-6 cytokine response. Poor immune activation may represent one mechanism whereby ABU E. coli evade immune detection after the establishment of bacteriuria.

UpaG, a new member of the Trimeric Autotransporter family of Adhesins in Uropathogenic Escherichia coli

The ability of Escherichia coli to colonize both intestinal and extraintestinal sites is driven by the presence of specific virulence factors, among which are the autotransporter (AT) proteins. Members of the trimeric AT adhesin family are important virulence factors for several gram-negative pathogens and mediate adherence to eukaryotic cells and extracellular matrix (ECM) proteins. In this study, we characterized a new trimeric AT adhesin (UpaG) from uropathogenic E. coli (UPEC). Molecular analysis of UpaG revealed that it is translocated to the cell surface and adopts a multimeric conformation. We demonstrated that UpaG is able to promote cell aggregation and biofilm formation on abiotic surfaces in CFT073 and various UPEC strains. In addition, UpaG expression resulted in the adhesion of CFT073 to human bladder epithelial cells, with specific affinity to fibronectin and laminin. Prevalence analysis revealed that upaG is strongly associated with E. coli strains from the B2 and D phylogenetic groups, while deletion of upaG had no significant effect on the ability of CFT073 to colonize the mouse urinary tract. Thus, UpaG is a novel trimeric AT adhesin from E. coli that mediates aggregation, biofilm formation, and adhesion to various ECM proteins.

The perspectives of older drivers on the impact of feedback on their driving behaviours : a qualitative study

Self-regulation is a coping strategy that allows older drivers to drive safely for longer. Self-regulation depends largely on the ability of drivers to evaluate their own driving. Therefore the success of self-regulation, in terms of driving safety, is influenced by the ability of older drivers to have insight into their declining driving performance. In addition, previous studies suggest that providing feedback to older adults regarding their driving skills may lead them to change their driving behaviour. However, little is currently known about the impact of feedback on older drivers’ self-awareness and their subsequent driving regulatory behaviour. This study explored the process of self-regulation and driving cessation among older drivers using the PAPM as a framework. It also investigated older adults’ perceptions and opinions about receiving feedback in regards to their driving abilities. Qualitative focus groups with 27 participants aged 70 years or more were conducted. Thematic analysis resulted in the development of five main themes; the meaning of driving, changes in driving pattern, feedback, the planning process, and solutions. The analysis also resulted in an initial model of driving self-regulation among older drivers that is informed by the current research and the Precaution Adoption Process Model as the theoretical framework. It identifies a number of social, personal, and environmental factors that can either facilitate or hinder people’s transition between stages of change. The findings from this study suggest that further elaboration of the PAPM is needed to take into account the role of insight and feedback on the process of self-regulation among older drivers.