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Find video protocols related to scientific articles indexed in Pubmed.
A Web-Based Cultural Competency Training for Medical Students: A Randomized Trial.
Am. J. Med. Sci.
PUBLISHED: 10-18-2014
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The objectives of this research were to compare a Web-based curriculum with a traditional lecture format on medical students' cultural competency attitudes using a standardized instrument and to examine the internal consistency of the standardized instrument.
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Teaching behaviors that define highest rated attending physicians: A study of the resident perspective.
Med Teach
PUBLISHED: 07-29-2014
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Abstract Background: Better understanding teaching behaviors of highly rated clinical teachers could improve training for teaching. We examined teaching behaviors demonstrated by higher rated attending physicians.
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Biohydrogen, biomethane and bioelectricity as crucial components of biorefinery of organic wastes: a review.
Waste Manag Res
PUBLISHED: 04-17-2014
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Biohydrogen is a sustainable form of energy as it can be produced from organic waste through fermentation processes involving dark fermentation and photofermentation. Very often biohydrogen is included as a part of biorefinery approaches, which reclaim organic wastes that are abundant sources of renewable and low cost substrate that can be efficiently fermented by microorganisms. The aim of this work was to critically assess selected bioenergy alternatives from organic solid waste, such as biohydrogen and bioelectricity, to evaluate their relative advantages and disadvantages in the context of biorefineries, and ?nally to indicate the trends for future research and development. Biorefining is the sustainable processing of biomass into a spectrum of marketable products, which means: energy, materials, chemicals, food and feed. Dark fermentation of organic wastes could be the beach-head of complete biorefineries that generate biohydrogen as a first step and could significantly influence the future of solid waste management. Series systems show a better efficiency than one-stage process regarding substrate conversion to hydrogen and bioenergy. The dark fermentation also produces fermented by-products (fatty acids and solvents), so there is an opportunity for further combining with other processes that yield more bioenergy. Photoheterotrophic fermentation is one of them: photosynthetic heterotrophs, such as non-sulfur purple bacteria, can thrive on the simple organic substances produced in dark fermentation and light, to give more H2. Effluents from photoheterotrophic fermentation and digestates can be processed in microbial fuel cells for bioelectricity production and methanogenic digestion for methane generation, thus integrating a diverse block of bioenergies. Several digestates from bioenergies could be used for bioproducts generation, such as cellulolytic enzymes and saccharification processes, leading to ethanol fermentation (another bioenergy), thus completing the inverse cascade. Finally, biohydrogen, biomethane and bioelectricity could contribute to significant improvements for solid organic waste management in agricultural regions, as well as in urban areas.
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The use of bi-layer silk fibroin scaffolds and small intestinal submucosa matrices to support bladder tissue regeneration in a rat model of spinal cord injury.
Biomaterials
PUBLISHED: 03-31-2014
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Adverse side-effects associated with enterocystoplasty for neurogenic bladder reconstruction have spawned the need for the development of alternative graft substitutes. Bi-layer silk fibroin (SF) scaffolds and small intestinal submucosa (SIS) matrices were investigated for their ability to support bladder tissue regeneration and function in a rat model of spinal cord injury (SCI). Bladder augmentation was performed with each scaffold configuration in SCI animals for 10 wk of implantation and compared to non-augmented control groups (normal and SCI alone). Animals subjected to SCI alone exhibited a 72% survival rate (13/18) while SCI rats receiving SIS and bi-layer SF scaffolds displayed respective survival rates of 83% (10/12) and 75% (9/12) over the course of the study period. Histological (Masson's trichrome analysis) and immunohistochemical (IHC) evaluations demonstrated both implant groups supported de novo formation of smooth muscle layers with contractile protein expression [?-smooth muscle actin (?-SMA) and SM22?] as well as maturation of multi-layer urothelia expressing cytokeratin (CK) and uroplakin 3A proteins. Histomorphometric analysis revealed bi-layer SF and SIS scaffolds respectively reconstituted 64% and 56% of the level of ?-SMA+ smooth muscle bundles present in SCI-alone controls, while similar degrees of CK+ urothelium across all experimental groups were detected. Parallel evaluations showed similar degrees of vascular area and synaptophysin+ boutons in all regenerated tissues compared to SCI-alone controls. In addition, improvements in certain urodynamic parameters in SCI animals, such as decreased peak intravesical pressure, following implantation with both matrix configurations were also observed. The data presented in this study detail the ability of acellular SIS and bi-layer SF scaffolds to support formation of innervated, vascularized smooth muscle and urothelial tissues in a neurogenic bladder model.
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Evaluation of a mobile voiding diary for pediatric patients with voiding dysfunction: a prospective comparative study.
J. Urol.
PUBLISHED: 03-20-2014
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One potential strategy for improving voiding diary completion rates and data quality is use of a mobile electronic format. We evaluated the acceptability and feasibility of mobile voiding diaries for patients with nonneurogenic lower urinary tract dysfunction, and compared mobile and paper voiding diaries.
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Direct involvement of the CreA transcription factor in penicillin biosynthesis and expression of the pcbAB gene in Penicillium chrysogenum.
Appl. Microbiol. Biotechnol.
PUBLISHED: 02-21-2014
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The transcription factor CreA is the main regulator responsible for carbon repression in filamentous fungi. CreA is a wide domain regulator that binds to regulatory elements in the promoters of target genes to repress their transcription. Penicillin biosynthesis and the expression of penicillin biosynthetic genes are subject to carbon repression. However, evidence of the participation of CreA in this regulation is still lacking, and previous studies on the promoter of the pcbC gene of Aspergillus nidulans indicated the lack of involvement of CreA in its regulation. Here we present clear evidence of the participation of CreA in carbon repression of penicillin biosynthesis and expression of the pcbAB gene, encoding the first enzyme of the pathway, in Penicillium chrysogenum. Mutations in cis of some of the putative CreA binding sites present in the pcbAB gene promoter fused to a reporter gene caused an important increase in the measured enzyme activity in glucose-containing medium, whereas activity in the medium with lactose was not affected. An RNAi strategy was used to attenuate the expression of the creA gene. Transformants expressing a small interfering RNA for creA showed higher penicillin production, and this increase was more evident when glucose was used as carbon source. These results confirm that CreA plays an important role in the regulation of penicillin biosynthesis in P. chrysogenum and opens the possibility of its utilization to improve the industrial production of this antibiotic.
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In vitro evaluation of bi-layer silk fibroin scaffolds for gastrointestinal tissue engineering.
J Tissue Eng
PUBLISHED: 01-01-2014
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Silk fibroin scaffolds were investigated for their ability to support attachment, proliferation, and differentiation of human gastrointestinal epithelial and smooth muscle cell lines in order to ascertain their potential for tissue engineering. A bi-layer silk fibroin matrix composed of a porous silk fibroin foam annealed to a homogeneous silk fibroin film was evaluated in parallel with small intestinal submucosa scaffolds. AlamarBlue analysis revealed that silk fibroin scaffolds supported significantly higher levels of small intestinal smooth muscle cell, colon smooth muscle cell, and esophageal smooth muscle cell attachment in comparison to small intestinal submucosa. Following 7?days of culture, relative numbers of each smooth muscle cell population maintained on both scaffold groups were significantly elevated over respective 1-day levels-indicative of cell proliferation. Real-time reverse transcription polymerase chain reaction and immunohistochemical analyses demonstrated that both silk fibroin and small intestinal submucosa scaffolds were permissive for contractile differentiation of small intestinal smooth muscle cell, colon smooth muscle cell, esophageal smooth muscle cell as determined by significant upregulation of ?-smooth muscle actin and SM22? messenger RNA and protein expression levels following transforming growth factor-?1 stimulation. AlamarBlue analysis demonstrated that both matrix groups supported similar degrees of attachment and proliferation of gastrointestinal epithelial cell lines including colonic T84 cells and esophageal epithelial cells. Following 14?days of culture on both matrices, spontaneous differentiation of T84 cells toward an enterocyte lineage was confirmed by expression of brush border enzymes, lactase, and maltase, as determined by real-time reverse transcription polymerase chain reaction and immunohistochemical analyses. In contrast to small intestinal submucosa scaffolds, silk fibroin scaffolds supported spontaneous differentiation of esophageal epithelial cells toward a suprabasal cell lineage as indicated by significant upregulation of cytokeratin 4 and cytokeratin 13 messenger RNA transcript levels. In addition, esophageal epithelial cells maintained on silk fibroin scaffolds also produced significantly higher involucrin messenger RNA transcript levels in comparison to small intestinal submucosa counterparts, indicating an increased propensity for superficial, squamous cell specification. Collectively, these data provide evidence for the potential of silk fibroin scaffolds for gastrointestinal tissue engineering applications.
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Rapid antigen group a streptococcus test to diagnose pharyngitis: a systematic review and meta-analysis.
PLoS ONE
PUBLISHED: 01-01-2014
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Pharyngitis management guidelines include estimates of the test characteristics of rapid antigen streptococcus tests (RAST) using a non-systematic approach.
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Acellular bi-layer silk fibroin scaffolds support tissue regeneration in a rabbit model of onlay urethroplasty.
PLoS ONE
PUBLISHED: 01-01-2014
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Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a rabbit model of urethra repair. A bi-layer silk fibroin matrix was fabricated by a solvent-casting/salt leaching process in combination with silk fibroin film casting to generate porous foams buttressed by homogeneous silk fibroin films. Ventral onlay urethroplasty was performed with silk fibroin grafts (Group 1, N = 4) (Width × Length, 1 × 2 cm(2)) in adult male rabbits for 3 m of implantation. Parallel control groups consisted of animals receiving small intestinal submucosa (SIS) implants (Group 2, N = 4) or urethrotomy alone (Group 3, N = 3). Animals in all groups exhibited 100% survival prior to scheduled euthanasia and achieved voluntary voiding following 7 d of initial catheterization. Retrograde urethrography of each implant group at 3 m post-op revealed wide urethral calibers and preservation of organ continuity similar to pre-operative and urethrotomy controls with no evidence of contrast extravasation, strictures, fistulas, or stone formation. Histological (hematoxylin and eosin and Masson's trichrome), immunohistochemical, and histomorphometric analyses demonstrated that both silk fibroin and SIS scaffolds promoted similar extents of smooth muscle and epithelial tissue regeneration throughout the original defect sites with prominent contractile protein (?-smooth muscle actin and SM22?) and cytokeratin expression, respectively. De novo innervation and vascularization were also evident in all regenerated tissues indicated by synaptophysin-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. Following 3 m post-op, minimal acute inflammatory reactions were elicited by silk fibroin scaffolds characterized by the presence of eosinophil granulocytes while SIS matrices promoted chronic inflammatory responses indicated by mobilization of mononuclear cell infiltrates. The results of this study demonstrate that bi-layer silk fibroin scaffolds represent promising biomaterials for onlay urethroplasty, capable of promoting similar degrees of tissue regeneration in comparison to conventional SIS scaffolds, but with reduced immunogenicity.
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Learning by doing: observing an interprofessional process as an interprofessional team.
J Interprof Care
PUBLISHED: 09-27-2013
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Abstract New competencies exist for interprofessional education, which are centered on the goal of improving quality of care and patient safety through improved interprofessional collaboration. Interprofessional education and effective interprofessional collaboration are cornerstones of the Veterans Affairs Quality Scholars fellowship program. The purpose of this project was to evaluate an innovative interprofessional education strategy in which teams of physicians and nurses were "learning by doing" as they observed and analyzed the functioning of an interprofessional process, specifically, inpatient discharge. Fellows completed voluntary, anonymous surveys seeking their perspectives about the project. Fellows feedback revealed several themes, with both positive and negative characteristics related to team functioning, interprofessional understanding, microsystem knowledge, pooled knowledge and assignment challenges. The strength of this strategy is exemplified by the fact that fellows not only learned from each others separate professional observations, but also observed the emergence of a shared interprofessional perspective through working together.
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Multi-planar Dynamic Contrast-Enhanced Ultrasound Assessment of Blood Flow in a Rabbit Model of Testicular Torsion.
Ultrasound Med Biol
PUBLISHED: 08-12-2013
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To assess correlation between multi-planar, dynamic contrast-enhanced ultrasound (US) blood flow measurements and radiolabeled microsphere blood flow measurements, five groups of six rabbits underwent unilateral testicular torsion of 0°, 180°, 360°, 540° or 720°. Five US measurements per testis (three transverse/two longitudinal) were obtained pre-operatively and immediately and 4 and 8 h post-operatively using linear transducers (7-4 MHz/center frequency 4.5 MHz/10 rabbits; 9-3 MHz/center frequency 5.5 MHz/20 rabbits). Björcks linear least-squares method fit the rise phase of mean pixel intensity over a 7-s period for each time curve. Slope of fit and intervention/control US pixel intensity ratios were calculated. Means of transverse, longitudinal and combined transverse/longitudinal US ratios as a function of torsion degree were compared with radiolabeled microsphere ratios using Pearsons correlation coefficient, ?. There was high correlation between the two sets of ratios (? ? 0.88, p ? 0.05), except for the transverse US ratio in the immediate post-operative period (? = 0.79, p = 0.11). These results hold promise for future clinical applications.
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Bladder tissue regeneration using acellular bi-layer silk scaffolds in a large animal model of augmentation cystoplasty.
Biomaterials
PUBLISHED: 06-04-2013
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Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a porcine model of augmentation cystoplasty. Two bi-layer matrix configurations were fabricated by solvent-casting/salt leaching either alone (Group 1) or in combination with silk film casting (Group 2) to yield porous foams buttressed by heterogeneous surface pore occlusions or homogenous silk films, respectively. Bladder augmentation was performed with each scaffold group (6 × 6 cm(2)) in juvenile Yorkshire swine for 3 m of implantation. Augmented animals exhibited high rates of survival (Group 1: 5/6, 83%; Group 2: 4/4, 100%) and voluntary voiding over the course of the study period. Urodynamic evaluations demonstrated mean increases in bladder capacity over pre-operative levels (Group 1: 277%; Group 2: 153%) which exceeded nonsurgical control gains (144%) encountered due to animal growth. Similarly, elevations in bladder compliance were substantially higher in augmented animals from baseline (Group 1: 357%; Group 2: 147%) in comparison to controls (41%). Gross tissue evaluations revealed that both matrix configurations supported extensive de novo tissue formation throughout the entire original implantation site which exhibited ultimate tensile strength similar to nonsurgical counterparts. Histological and immunohistochemical analyses showed that both implant groups promoted comparable extents of smooth muscle regeneration and contractile protein (?-smooth muscle actin and SM22?) expression within defect sites similar to controls. Parallel evaluations demonstrated the formation of a transitional, multi-layered urothelium with prominent cytokeratin, uroplakin, and p63 protein expression in both matrix groups. De novo innervation and vascularization processes were evident in all regenerated tissues indicated by synaptophysin-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. Ex vivo organ bath studies demonstrated that regenerated tissues supported by both silk matrices displayed contractile responses to carbachol, ?,?-methylene-ATP, KCl, and electrical field stimulation similar to controls. Our data detail the ability of acellular silk scaffolds to support regeneration of innervated, vascularized smooth muscle and urothelial tissues within 3 m with structural, mechanical, and functional properties comparable to native tissue in a porcine model of bladder repair.
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Molecular characterization of the PR-toxin gene cluster in Penicillium roqueforti and Penicillium chrysogenum: Cross talk of secondary metabolite pathways.
Fungal Genet. Biol.
PUBLISHED: 05-09-2013
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The PR-toxin is a potent mycotoxin produced by Penicillium roqueforti in moulded grains and grass silages and may contaminate blue-veined cheese. The PR-toxin derives from the 15 carbon atoms sesquiterpene aristolochene formed by the aristolochene synthase (encoded by ari1). We have cloned and sequenced a four gene cluster that includes the ari1 gene from P. roqueforti. Gene silencing of each of the four genes (named prx1 to prx4) resulted in a reduction of 65-75% in the production of PR-toxin indicating that the four genes encode enzymes involved in PR-toxin biosynthesis. Interestingly the four silenced mutants overproduce large amounts of mycophenolic acid, an antitumor compound formed by an unrelated pathway suggesting a cross-talk of PR-toxin and mycophenolic acid production. An eleven gene cluster that includes the above mentioned four prx genes and a 14-TMS drug/H(+) antiporter was found in the genome of Penicillium chrysogenum. This eleven gene cluster has been reported to be very poorly expressed in a transcriptomic study of P. chrysogenum genes under conditions of penicillin production (strongly aerated cultures). We found that this apparently silent gene cluster is able to produce PR-toxin in P. chrysogenum under static culture conditions on hydrated rice medium. Noteworthily, the production of PR-toxin was 2.6-fold higher in P. chrysogenum npe10, a strain deleted in the 56.8kb amplifiable region containing the pen gene cluster, than in the parental strain Wisconsin 54-1255 providing another example of cross-talk between secondary metabolite pathways in this fungus. A detailed PR-toxin biosynthesis pathway is proposed based on all available evidence.
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Clinical reasoning for the infectious disease specialist: a primer to recognize cognitive biases.
Clin. Infect. Dis.
PUBLISHED: 04-17-2013
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Infectious disease specialists are frequently consulted for diagnostic and therapeutic advice on challenging cases. When evaluating patients, the infectious disease specialist is well positioned to offer an appropriate diagnostic approach but is also at risk of not recognizing the correct diagnosis for a variety of reasons. We believe it is important to provide infectious disease specialists and trainees with a fundamental understanding of diagnostic errors, clinical reasoning, and cognitive biases. We present 2 cases demonstrating common cognitive biases leading to diagnostic errors, and we reflect on strategies that may aid in their prevention. We hope to provide knowledge and tools that may help prevent diagnostic errors in the future.
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Widening the differential for brain masses in human immunodeficiency virus-positive patients: syphilitic cerebral gummata.
Am. J. Med. Sci.
PUBLISHED: 04-17-2013
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A 39-year-old man with newly diagnosed human immunodeficiency virus (HIV) infection was admitted with right-sided weakness, right-sided vision loss and slurred speech, which worsened over several weeks. Brain imaging revealed bilateral intraparenchymal ring-enhancing lesions and enhancement of the right optic nerve. Serological findings were positive for venereal disease research laboratory test, whereas the cerebrospinal fluid venereal disease research laboratory test was nonreactive. Brain biopsy suggested a diagnosis of syphilitic cerebral gummata, and the patients improvement with penicillin and dexamethasone further supported this etiology. Syphilitic cerebral gummata have rarely been reported in patients with HIV infection. This patient demonstrates that cerebral gummata should be considered in the differential diagnosis in immunocompromised patients with characteristic brain masses, that HIV and syphilis often coexist with early neurosyphilis appearing more frequently in this patient population and that normal cerebrospinal fluid studies may not represent a true lack of syphilitic activity in HIV patients.
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The influence of total solids content and initial pH on batch biohydrogen production by solid substrate fermentation of agroindustrial wastes.
J. Environ. Manage.
PUBLISHED: 04-04-2013
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Hydrogen is a valuable clean energy source, and its production by biological processes is attractive and environmentally sound and friendly. In México 5 million tons/yr of agroindustrial wastes are generated; these residues are rich in fermentable organic matter that can be used for hydrogen production. On the other hand, batch, intermittently vented, solid substrate fermentation of organic waste has attracted interest in the last 10 years. Thus the objective of our work was to determine the effect of initial total solids content and initial pH on H2 production in batch fermentation of a substrate that consisted of a mixture of sugarcane bagasse, pineapple peelings, and waste activated sludge. The experiment was a response surface based on 2(2) factorial with central and axial points with initial TS (15-35%) and initial pH (6.5-7.5) as factors. Fermentation was carried out at 35 °C, with intermittent venting of minireactors and periodic flushing with inert N2 gas. Up to 5 cycles of H2 production were observed; the best treatment in our work showed cumulative H2 productions (ca. 3 mmol H2/gds) with 18% and 6.65 initial TS and pH, respectively. There was a significant effect of TS on production of hydrogen, the latter decreased with initial TS increase from 18% onwards. Cumulative H2 productions achieved in this work were higher than those reported for organic fraction of municipal solid waste (OFMSW) and mixtures of OFMSW and fruit peels waste from fruit juice industry, using the same process. Specific energetic potential due to H2 in our work was attractive and fell in the high side of the range of reported results in the open literature. Batch dark fermentation of agrowastes as practiced in our work could be useful for future biorefineries that generate biohydrogen as a first step and could influence the management of this type of agricultural wastes in México and other countries and regions as well.
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A multimethod approach for cross-cultural training in an internal medicine residency program.
Med Educ Online
PUBLISHED: 03-18-2013
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Cultural competence training in residency is important to improve learners confidence in cross-cultural encounters. Recognition of cultural diversity and avoidance of cultural stereotypes are essential for health care providers.
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Documenting Quality Improvement and Patient Safety Efforts: The Quality Portfolio. A Statement from the Academic Hospitalist Taskforce.
J Gen Intern Med
PUBLISHED: 03-17-2013
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Physicians increasingly investigate, work, and teach to improve the quality of care and safety of care delivery. The Society of General Internal Medicine Academic Hospitalist Task Force sought to develop a practical tool, the quality portfolio, to systematically document quality and safety achievements. The quality portfolio was vetted with internal and external stakeholders including national leaders in academic medicine. The portfolio was refined for implementation to include an outlined framework, detailed instructions for use and an example to guide users. The portfolio has eight categories including: (1) a faculty narrative, (2) leadership and administrative activities, (3) project activities, (4) education and curricula, (5) research and scholarship, (6) honors, awards, and recognition, (7) training and certification, and (8) an appendix. The authors offer this comprehensive, yet practical tool as a method to document quality and safety activities. It is relevant for physicians across disciplines and institutions and may be useful as a standalone document or as an adjunct to traditional promotion documents. As the Next Accreditation System is implemented, academic medical centers will require faculty who can teach and implement the systems-based practice requirements. The quality portfolio is a method to document quality improvement and safety activities.
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Hydroxyethyl starch in severe sepsis: end of starch era?
Crit Care
PUBLISHED: 03-13-2013
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EXPANDED ABSTRACT: CITATION: Perner A, Haase N, Guttormsen AB, Tenhunen J, Klemenzson G, Åneman A, Madsen KR, Møller MH, Elkjær JM, Poulsen LM, Bendtsen A, Winding R, Steensen M, Berezowicz P, Søe-Jensen P, Bestle M, Strand K, Wiis J, White JO, Thornberg KJ, Quist L, Nielsen J, Andersen LH, Holst LB, Thormar K, Kjældgaard AL, Fabritius ML, Mondrup F, Pott FC, Møller TP, Winkel P, Wetterslev J; 6S Trial Group; Scandinavian Critical Care Trials Group: Hydroxyethyl starch 130/0.42 versus Ringers acetate in severe sepsis. N Engl J Med 2012, 367:124-34. BACKGROUND: Hydroxyethyl starch (HES) is widely used for fluid resuscitation in ICUs, but its safety and efficacy have not been established in patients with severe sepsis. METHODS: OBJECTIVE: To assess the effects of HES 130/0.4 compared with a balanced crystalloid solution on mortality and end-stage kidney failure in patients with severe sepsis. DESIGN: Multicenter, parallel-group, blinded, randomized clinical trial, in patients with severe sepsis. INTERVENTIONS: Patients with severe sepsis admitted to the ICU received fluid resuscitation with either 6% HES 130/0.42 (Tetraspan) or Ringers acetate at a dose of up to 33 ml per kilogram of ideal body weight per day. RESULTS: Of the 804 patients who underwent randomization, 798 were included in the modified intention-to-treat population. The two intervention groups had similar baseline characteristics. At 90 days after randomization, 201 of 398 patients (51%) assigned to HES 130/0.42 had died, as compared with 172 of 400 patients (43%) assigned to Ringers acetate (relative risk, 1.17; 95% confidence interval (CI), 1.01 to 1.36; P = 0.03); 1 patient in each group had end-stage kidney failure. In the 90-day period, 87 patients (22%) assigned to HES 130/0.42 were treated with renal replacement therapy versus 65 patients (16%) assigned to Ringers acetate (relative risk, 1.35; 95% CI, 1.01 to 1.80; P = 0.04), and 38 patients (10%) and 25 patients (6%), respectively, had severe bleeding (relative risk, 1.52; 95% CI, 0.94 to 2.48; P = 0.09). The results were supported by multivariate analyses, with adjustment for known risk factors for death or acute kidney injury at baseline. CONCLUSIONS: Patients with severe sepsis assigned to fluid resuscitation with HES 130/0.42 had an increased risk of death at day 90 and were more likely to require renal replacement therapy compared with those receiving Ringers acetate.
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The performance of silk scaffolds in a rat model of augmentation cystoplasty.
Biomaterials
PUBLISHED: 02-25-2013
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The diverse processing plasticity of silk-based biomaterials offers a versatile platform for understanding the impact of structural and mechanical matrix properties on bladder regenerative processes. Three distinct groups of 3-D matrices were fabricated from aqueous solutions of Bombyx mori silk fibroin either by a gel spinning technique (GS1 and GS2 groups) or a solvent-casting/salt-leaching method in combination with silk film casting (FF group). SEM analyses revealed that GS1 matrices consisted of smooth, compact multi-laminates of parallel-oriented silk fibers while GS2 scaffolds were composed of porous (pore size range, 5-50 ?m) lamellar-like sheets buttressed by a dense outer layer. Bi-layer FF scaffolds were comprised of porous foams (pore size, ~400 ?m) fused on their external face with a homogenous, nonporous silk film. Silk groups and small intestinal submucosa (SIS) matrices were evaluated in a rat model of augmentation cystoplasty for 10 weeks of implantation and compared to cystotomy controls. Gross tissue evaluations revealed the presence of intra-luminal stones in all experimental groups. The incidence and size of urinary calculi was the highest in animals implanted with gel spun silk matrices and SIS with frequencies ?57% and stone diameters of 3-4 mm. In contrast, rats augmented with FF scaffolds displayed substantially lower rates (20%) and stone size (2 mm), similar to the levels observed in controls (13%, 2 mm). Histological (hematoxylin and eosin, Massons trichrome) and immunohistochemical (IHC) analyses showed comparable extents of smooth muscle regeneration and contractile protein (?-smooth muscle actin and SM22?) expression within defect sites supported by all matrix groups similar to controls. Parallel evaluations demonstrated the formation of a transitional, multi-layered urothelium with prominent uroplakin and p63 protein expression in all experimental groups. De novo innervation and vascularization processes were evident in all regenerated tissues indicated by Fox3-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. In comparison to other biomaterial groups, cystometric analyses at 10 weeks post-op revealed that animals implanted with the FF matrix configuration displayed superior urodynamic characteristics including compliance, functional capacity, as well as spontaneous non voiding contractions consistent with control levels. Our data demonstrate that variations in scaffold processing techniques can influence the in vivo functional performance of silk matrices in bladder reconstructive procedures.
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The inducers 1,3-diaminopropane and spermidine cause the reprogramming of metabolism in Penicillium chrysogenum, leading to multiple vesicles and penicillin overproduction.
J Proteomics
PUBLISHED: 02-21-2013
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In this article we studied the differential protein abundance of Penicillium chrysogenum in response to either 1,3-diaminopropane (1,3-DAP) or spermidine, which behave as inducers of the penicillin production process. Proteins were resolved in 2-DE gels and identified by tandem MS spectrometry. Both inducers produced largely identical changes in the proteome, suggesting that they may be interconverted and act by the same mechanism. The addition of either 1,3-DAP or spermidine led to the overrepresentation of the last enzyme of the penicillin pathway, isopenicillin N acyltransferase (IAT). A modified form of the IAT protein was newly detected in the polyamine-supplemented cultures. Both inducers produced a rearrangement of the proteome resulting in an overrepresentation of enzymes involved in the biosynthesis of valine and other precursors (e.g. coenzyme A) of penicillin. Interestingly, two enzymes of the homogentisate pathway involved in the degradation of phenylacetic acid (a well-known precursor of benzylpenicillin) were reduced following the addition of either of these two inducers, allowing an increase of the phenylacetic acid availability. Both inducers produced also an increase in the intracellular content of vesicles that derived to vacuoles in late stages and promoted sporulation of P. chrysogenum in solid medium.
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Decreasing the ceiling effect in assessing meeting quality at an academic professional meeting.
Teach Learn Med
PUBLISHED: 01-22-2013
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The psychometric properties of evaluations at academic meetings have not been well studied.
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Evaluation of silk biomaterials in combination with extracellular matrix coatings for bladder tissue engineering with primary and pluripotent cells.
PLoS ONE
PUBLISHED: 01-11-2013
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Silk-based biomaterials in combination with extracellular matrix (ECM) coatings were assessed as templates for cell-seeded bladder tissue engineering approaches. Two structurally diverse groups of silk scaffolds were produced by a gel spinning process and consisted of either smooth, compact multi-laminates (Group 1) or rough, porous lamellar-like sheets (Group 2). Scaffolds alone or coated with collagen types I or IV or fibronectin were assessed independently for their ability to support attachment, proliferation, and differentiation of primary cell lines including human bladder smooth muscle cells (SMC) and urothelial cells as well as pluripotent cell populations, such as murine embryonic stem cells (ESC) and induced pluripotent stem (iPS) cells. AlamarBlue evaluations revealed that fibronectin-coated Group 2 scaffolds promoted the highest degree of primary SMC and urothelial cell attachment in comparison to uncoated Group 2 controls and all Group 1 scaffold variants. Real time RT-PCR and immunohistochemical (IHC) analyses demonstrated that both fibronectin-coated silk groups were permissive for SMC contractile differentiation as determined by significant upregulation of ?-actin and SM22? mRNA and protein expression levels following TGF?1 stimulation. Prominent expression of epithelial differentiation markers, cytokeratins, was observed in urothelial cells cultured on both control and fibronectin-coated groups following IHC analysis. Evaluation of silk matrices for ESC and iPS cell attachment by alamarBlue showed that fibronectin-coated Group 2 scaffolds promoted the highest levels in comparison to all other scaffold formulations. In addition, real time RT-PCR and IHC analyses showed that fibronectin-coated Group 2 scaffolds facilitated ESC and iPS cell differentiation toward both urothelial and smooth muscle lineages in response to all trans retinoic acid as assessed by induction of uroplakin and contractile gene and protein expression. These results demonstrate that silk scaffolds support primary and pluripotent cell responses pertinent to bladder tissue engineering and that scaffold morphology and fibronectin coatings influence these processes.
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NRPSsp: non-ribosomal peptide synthase substrate predictor.
Bioinformatics
PUBLISHED: 11-29-2011
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Non-ribosomal peptide synthetases (NRPSs) are multi-modular enzymes, which biosynthesize many important peptide compounds produced by bacteria and fungi. Some studies have revealed that an individual domain within the NRPSs shows significant substrate selectivity. The discovery and characterization of non-ribosomal peptides are of great interest for the biotechnological industries. We have applied computational mining methods in order to build a database of NRPSs modules that bind to specific substrates. We have used this database to build a hidden Markov model predictor of substrates that bind to a given NRPS.
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Role of peroxisomes in the biosynthesis and secretion of ?-lactams and other secondary metabolites.
J. Ind. Microbiol. Biotechnol.
PUBLISHED: 09-28-2011
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Peroxisomes are eukaryotic organelles surrounded by a single bilayer membrane, containing a variety of proteins depending on the organism; they mainly perform degradation reactions of toxic metabolites (detoxification), catabolism of linear and branched-chain fatty acids, and removal of H(2)O(2) (formed in some oxidative processes) by catalase. Proteins named peroxins are involved in recruiting, transporting, and introducing the peroxisomal matrix proteins into the peroxisomes. The matrix proteins contain the peroxisomal targeting signals PTS1 and/or PTS2 that are recognized by the peroxins Pex5 and Pex7, respectively. Initial evidence indicated that the penicillin biosynthetic enzyme isopenicillin N acyltransferase (IAT) of Penicillium chrysogenum is located inside peroxisomes. There is now solid evidence (based on electron microscopy and/or biochemical data) confirming that IAT and the phenylacetic acid- and fatty acid-activating enzymes are also located in peroxisomes. Similarly, the Acremonium chrysogenum CefD1 and CefD2 proteins that perform the central reactions (activation and epimerization of isopenicillin N) of the cephalosporin pathway are targeted to peroxisomes. Growing evidence supports the conclusion that some enzymes involved in the biosynthesis of mycotoxins (e.g., AK-toxin), and the biosynthesis of signaling molecules in plants (e.g., jasmonic acid or auxins) occur in peroxisomes. The high concentration of substrates (in many cases toxic to the cytoplasm) and enzymes inside the peroxisomes allows efficient synthesis of metabolites with interesting biological or pharmacological activities. This compartmentalization poses additional challenges to the cell due to the need to import the substrates into the peroxisomes and to export the final products; the transporters involved in these processes are still very poorly known. This article focuses on new aspects of the metabolic processes occurring in peroxisomes, namely the degradation and detoxification processes that lead to the biosynthesis and secretion of secondary metabolites.
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Selecting the best clinical vignettes for academic meetings: should the scoring tool criteria be modified?
J Gen Intern Med
PUBLISHED: 09-01-2011
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The performance of scoring tools to select clinical vignettes for presentation at academic meetings has never been assessed.
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A single cluster of coregulated genes encodes the biosynthesis of the mycotoxins roquefortine C and meleagrin in Penicillium chrysogenum.
Chem. Biol.
PUBLISHED: 08-25-2011
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A single gene cluster of Penicillium chrysogenum contains genes involved in the biosynthesis and secretion of the mycotoxins roquefortine C and meleagrin. Five of these genes have been silenced by RNAi. Pc21g15480 (rds) encodes a nonribosomal cyclodipeptide synthetase for the biosynthesis of both roquefortine C and meleagrin. Pc21g15430 (rpt) encodes a prenyltransferase also required for the biosynthesis of both mycotoxins. Silencing of Pc21g15460 or Pc21g15470 led to a decrease in roquefortine C and meleagrin, whereas silencing of the methyltransferase gene (Pc21g15440; gmt) resulted in accumulation of glandicolin B, indicating that this enzyme catalyzes the conversion of glandicolin B to meleagrin. All these genes are transcriptionally coregulated. Our results prove that roquefortine C and meleagrin derive from a single pathway.
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A web-based diabetes intervention for physician: a cluster-randomized effectiveness trial.
Int J Qual Health Care
PUBLISHED: 08-10-2011
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To determine the effectiveness of a provider-based education and implementation intervention for improving diabetes control.
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Leishmania donovani: proteasome-mediated down-regulation of methionine adenosyltransferase.
Parasitology
PUBLISHED: 08-05-2011
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Methionine adenosyltransferase (MAT) is an important enzyme for metabolic processes, to the extent that its product, S-adenosylmethionine (AdoMet), plays a key role in trans-methylation, trans-sulphuration and polyamine synthesis. Previous studies have shown that a MAT-overexpressing strain of Leishmania donovani controls AdoMet production, keeping the intracellular AdoMet concentration at levels that are compatible with cell survival. This unexpected result, together with the fact that MAT activity and abundance changed with time in culture, suggests that different regulatory mechanisms acting beyond the post-transcriptional level are controlling this protein. In order to gain an insight into these mechanisms, several experiments were carried out to explain the MAT abundance during promastigote cell growth. Determination of MAT turnover in cycloheximide (CHX)-treated cultures resulted in a surprising 5-fold increase in MAT turnover compared to CHX-untreated cultures. This increase agrees with a stabilization of the MAT protein, whose integrity was maintained during culture. The presence of proteasome inhibitors, namely MG-132, MG-115, epoxomycin and lactacystin in the culture medium prevented MAT degradation in both MAT-overexpressing and mock-transfected leishmanial strains. The role of the ubiquitin (Ub) pathway in MAT down-regulation was supported using immunoprecipitation experiments. Immunoprecipitated MAT cross-reacted with anti-Ub antibodies, which provides evidence of a proteasome-mediated down-regulation of the leishmanial MAT abundance.
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Nominal group technique: a brainstorming tool for identifying areas to improve pain management in hospitalized patients.
J Hosp Med
PUBLISHED: 08-04-2011
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Pain management in hospitalized patients remains a priority area for improvement; effective strategies for consensus development are needed to prioritize interventions.
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Experimental characterization of temperature sensitive dyes for laser induced fluorescence thermometry.
Rev Sci Instrum
PUBLISHED: 08-03-2011
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Laser induced fluorescence (LIF) is a non-intrusive optical technique that uses fluorescent dyes to measure whole-field fluid scalars such as temperature, concentration, pH, etc. LIF measurements accuracy is strongly influenced by the fluorescent dyes behavior under different experimental conditions. In particular, ratiometric LIF thermometry accuracy depends on the correct selection of fluorescent dyes mixtures. Therefore, a thorough characterizations of fluorescent dyes is needed to obtain optimal mixtures and suitable optical configurations for given experimental conditions. This work presents the experimental characterization of fluorescein-27 (FL27) and rhodamine-B (RhB) mixtures to determine suitable aqueous solutions for ratiometric LIF thermometry. The mixtures fluorescence emission intensity was measured with a spectrofluorometer, and the influence of concentration ratio (C(RhB)/C(FL27)), temperature, excitation wavelength (?(ext)), and pH were analyzed. The results show that the temperature dependence of FL27 emission intensity changed from a negative to a positive value as the excitation wavelength increased. The temperature sensitivity (4.0% per °C) of RhB and FL27 mixture under 532 nm excitation wavelength was found to be higher than that of the commonly used mixture of RhB and Rh110 (2.0% per °C) at the same excitation wavelength. While the emission intensities of the dyes are sensitive to pH value, the temperature dependence is unaffected. The influence of concentration ratio on temperature sensitivity depends on both the detected bands of the emitted spectrum and the temperature; the concentration ratio should be selected based on the measured temperature scope. A new multicolor method or advanced two color method with high temperature sensitivity (6.0% or 10.0% per °C) is presented. This technique was specially developed to improve whole-field temperature measurements.
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Characterization of an autoinducer of penicillin biosynthesis in Penicillium chrysogenum.
Appl. Environ. Microbiol.
PUBLISHED: 07-01-2011
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Filamentous fungi produce an impressive variety of secondary metabolites; many of them have important biological activities. The biosynthesis of these secondary metabolites is frequently induced by plant-derived external elicitors and appears to also be regulated by internal inducers, which may work in a way similar to that of bacterial autoinducers. The biosynthesis of penicillin in Penicillium chrysogenum is an excellent model for studying the molecular mechanisms of control of gene expression due to a good knowledge of the biochemistry and molecular genetics of ?-lactam antibiotics and to the availability of its genome sequence and proteome. In this work, we first developed a plate bioassay that allows direct testing of inducers of penicillin biosynthesis using single colonies of P. chrysogenum. Using this bioassay, we have found an inducer substance in the conditioned culture broths of P. chrysogenum and Acremonium chrysogenum. No inducing effect was exerted by ?-butyrolactones, jasmonic acid, or the penicillin precursor ?-(L-?-aminoadipyl)-L-cysteinyl-D-valine. The conditioned broth induced penicillin biosynthesis and transcription of the pcbAB, pcbC, and penDE genes when added at inoculation time, but its effect was smaller if added at 12 h and it had no effect when added at 24 h, as shown by Northern analysis and lacZ reporter studies. The inducer molecule was purified and identified by mass spectrometry (MS) and nuclear magnetic resonance (NMR) as 1,3-diaminopropane. Addition of pure 1,3-diaminopropane stimulated the production of penicillin by about 100% compared to results for the control cultures. Genes for the biosynthesis of 1,3-diaminopropane have been identified in the P. chrysogenum genome.
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Contemporary use of nephron-sparing surgery for children with malignant renal tumors at freestanding childrens hospitals.
Urology
PUBLISHED: 06-22-2011
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It is widely accepted that, when feasible, nephron-sparing surgery (NSS) is preferable to radical nephrectomy (RN) for treatment of renal tumors in adults. However, RN is more frequently used in children. We sought to compare in-hospital outcomes after NSS and RN for malignant pediatric renal tumors.
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The effect of manipulation of silk scaffold fabrication parameters on matrix performance in a murine model of bladder augmentation.
Biomaterials
PUBLISHED: 06-15-2011
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Autologous gastrointestinal segments are utilized as the primary option for bladder reconstructive procedures despite their inherent morbidity and significant complication rate. Multi-laminate biomaterials derived from Bombyx mori silk fibroin and prepared from a gel spinning process may serve as a superior alternative for bladder tissue engineering due to their robust mechanical properties, biocompatibility, and processing plasticity. In the present study, we sought to determine the impact of variations in winding (axial slew rate: 2 and 40 mm/s) and post-winding (methanol and lyophilization) fabrication parameters on the in vivo performance of gel spun silk scaffolds in a murine model of bladder augmentation. Three silk matrix groups with distinct structural and mechanical properties were investigated following 10 weeks of implantation including our original prototype previously shown to support bladder regeneration, Group 1 (2 mm/s, methanol) as well as Group 2 (40 mm/s, methanol) and Group 3 (40 mm/s, lyophilization) configurations. Non surgical animals were assessed in parallel as controls. Quantification of residual scaffold area demonstrated that while Group 1 and 2 scaffolds were largely intact, processing parameters utilized for Group 3 led to significantly higher degrees of scaffold degradation in comparison to Group 1. Histological (hematoxylin and eosin, massons trichrome) and immunohistochemical (IHC) analyses showed comparable extents of smooth muscle regeneration and contractile protein (?-smooth muscle actin and SM22?) expression within the original defect site throughout all matrix groups similar to controls. Parallel evaluations demonstrated transitional urothelial formation with prominent uroplakin and p63 protein expression supported by Group 1 and 3 scaffolds, while Group 2 variants supported a thin, immature epithelium composed primarily of uroplakin-negative, p63-positive basal cells. Voided stain on paper analysis revealed similar voiding patterns between all matrix groups; however Group 2 animals displayed substantially lower voided volumes with increased frequency in comparison to controls. In addition, cystometric assessments revealed all matrix groups supported comparable degrees of bladder compliance similar to control levels. The results of this study demonstrate that selective alterations in winding and post-winding fabrication parameters can enhance the degradation rate of gel spun silk scaffolds in vivo while preserving their ability to support bladder tissue regeneration and function.
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Patient complexity and diabetes quality of care in rural settings.
J Natl Med Assoc
PUBLISHED: 06-15-2011
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Even though pay-for-performance programs are being rapidly implemented, little is known about how patient complexity affects practice-level performance assessment in rural settings. We sought to determine the association between patient complexity and practice-level performance in the rural United States.
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Motifs in the C-terminal region of the Penicillium chrysogenum ACV synthetase are essential for valine epimerization and processivity of tripeptide formation.
Biochimie
PUBLISHED: 05-12-2011
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The first step in the penicillin biosynthetic pathway is the non-ribosomal condensation of L-?-aminoadipic acid, L-cysteine and L-valine into the tripeptide ?-(L-?-aminoadipyl)-L-cysteinyl-D-valine (ACV). This reaction is catalysed by the multienzyme ACV synthetase (ACVS), which is encoded in the filamentous fungus Penicillium chrysogenum by the pcbAB gene. This enzyme contains at least ten catalytic domains. The precise role of the C-terminal domain of this multidomain NRPS still remains obscure. The C-terminal region of ACVS bears the epimerase and the thioesterase domains and may be involved in the epimerization of LLL-ACV to LLD-ACV and in the hydrolysis of the thioester bond. In this work, the conserved motifs (3371)EGHGRE(3376) (located in the putative epimerase domain) and (3629)GWSFG(3633) (located in the thioesterase domain) were changed by site-directed-mutagenesis to LGFGLL and GWAFG, respectively. In addition, the whole thioesterase domain (230 amino acids) and the different parts of this domain were deleted. The activity of these mutant enzymes was assessed in vivo by two different procedures: i) through the quantification of bisACV produced by the fungus and ii) by quantifying the benzylpenicillin production using tailored strains of P. chrysogenum, which lack the pcbAB gene, as host strains. All indicated mutant enzymes showed lower or null activity than the control strain confirming that E3371, H3373, R3375 and E3376 belong to the epimerase active centre. Different fragments included in the C-terminal region of ACVS control thioester hydrolysis. Overexpression of the sequence encoding the ACVS integrated thioesterase domain as a separate (stand-alone) transcriptional unit complemented mutants lacking the integrated thioesterase domain, although with low ACV releasing activity, suggesting that the stand-alone thioesterease interacts with the other ACVS domains.
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A new species of Eudusbabekia (Acari: Prostigmata: Myobiidae) from Harts little fruit bat, Enchistenes hartii (Chiroptera: Phyllostomidae), in southern Mexico.
J. Med. Entomol.
PUBLISHED: 04-13-2011
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Eudusbabekia paralepidoseta new species, was recorded on the Harts little fruit bat Enchistenes hartii (Thomas) in the southern part of Mexico. The female and male are described and illustrated. E. paralepidoseta n. sp. represents the 32nd species in the genus. From the 31 known species of Eudusbabekia known to infest phyllostomid and mormoopid bats, E. paralepidoseta n. sp. has some morphological features similar to Eudusbabekia lepidoseta Jameson, 1971, including shapes of almost all dorsal and ventral setae; the presence of a patch of supernumerary; mostly broad to thick, medium, and almost scale-like setae; and the absence of setae 2b. However, E. paralepidoseta n. sp. can be differentiated from E. lepidoseta, by the reduced number of supernumerary setae on the female venter (37-43). The close morphological and therefore evolutionary similarities between E. lepidoseta and E. paralepidoseta n. sp. suggest possible close evolutionary relationships between their hosts, Sturnira lilium (Geoffroyi and St.-Hilaire) and E. hartii, which belong to the monophyletic subfamily Stenodermatinae.
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Preparing for oral scientific and clinical vignette presentations.
J Grad Med Educ
PUBLISHED: 03-28-2011
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Little is known about how faculty, residents, and fellows practice for oral presentations at academic meetings. We sought to categorize presenters practice styles and the impact of feedback.
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Marketing to increase participation in a Web-based continuing medical education cultural competence curriculum.
J Contin Educ Health Prof
PUBLISHED: 03-23-2011
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CME providers may be interested in identifying effective marketing strategies to direct users to specific content. Online advertisements for recruiting participants into activities such as clinical trials, public health programs, and continuing medical education (CME) have been effective in some but not all studies. The purpose of this study was to compare the impact of 2 marketing strategies in the context of an online CME cultural competence curriculum (www.c-comp.org).
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Penicillium chrysogenum var. halophenolicum, a new halotolerant strain with potential in the remediation of aromatic compounds in high salt environments.
Microbiol. Res.
PUBLISHED: 03-12-2011
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A halotolerant phenylacetate-degrading fungus Penicillium CLONA2, previously isolated from a salt mine at Algarve (Portugal), was identified as a variant of P. chrysogenum using the ITS-5,8S rDNA and the D1/D2 domain of 28S rDNA sequences. The metabolic features and genetic characteristics suggest that this strain belongs to a subgroup of P. chrysogenum, named var. halophenolicum. The presence of the penicillin biosynthetic cluster was proven by Southern hybridizations using probes internal to the pcbAB and penDE genes and sequencing of the pcbAB-pcbC intergenic region. However the pcbAB-pcbC divergent promoter region contained 20 point modifications with respect to that of the wild type P. chrysogenum NRRL1951. The CLONA2 strain produced non-aromatic natural penicillins rather than benzylpenicillin in a medium containing potassium phenylacetate (the precursor of benzylpenicillin) and was able to grow well on phenylacetatic acid using it as sole carbon source. Due to the ability of P. chrysogenum CLONA2 to degrade aromatic compounds, this strain may be an interesting organism for aromatic compounds remediation in high salinity environments.
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CD8?? dendritic cells improve collagen-induced arthritis in CC chemokine receptor (CCR)-2 deficient mice.
Immunobiology
PUBLISHED: 02-23-2011
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Dendritic cells (DCs) have long been recognized as potential therapeutic targets of rheumatoid arthritis (RA). Increasing evidence has showed that DCs are capable of suppressing autoimmunity by expanding FoxP3? regulatory T cells (T(reg)), which in turn exert immunosuppression by increasing TGF?-1. In the SKG mice, activated DC prime autoreactive T cells causing autoantibody production and an inflammatory arthritic response. Recently, we reported that CC-chemokine receptor-2 deficient (Ccr2?/?) mice had impaired DCs migration and reduced CD8?? DCs in the C57Bl/6J mice strain and that these mice were more susceptible to collagen antibody-induced arthritis (CAIA), compared to wild type mice. To examine the mechanism by which DCs contribute to the increased susceptibility of arthritis in Ccr2?/? mice, we tested the hypothesis that CD8?? DCs are protective (tolerogenic) against autoimmune arthritis by examining the role of CD8?? DCs in Ccr2?/? and SKG mice.
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Screening for malignancy after augmentation cystoplasty in children with spina bifida: a decision analysis.
J. Urol.
PUBLISHED: 02-09-2011
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Augmentation cystoplasty is the mainstay of surgical treatment for medically refractory neurogenic bladder in patients with spina bifida. Concerns regarding an increased risk of malignancy have prompted many centers to consider routine postoperative screening. We examine the potential cost-effectiveness of such screening.
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Evidence-based medicine training in a resource-poor country, the importance of leveraging personal and institutional relationships.
J Eval Clin Pract
PUBLISHED: 01-30-2011
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Efforts to implement evidence-based medicine (EBM) training in developing countries are limited. We describe the results of an international effort to improve research capacity in a developing country; we conducted a course aimed at improving basic EBM attitudes and identified challenges.
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Intermittent ureterovesical junction obstruction in children.
J Pediatr Urol
PUBLISHED: 01-26-2011
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While intermittent ureteropelvic junction obstruction is well recognized clinically, intermittent obstruction at the ureterovesical junction has not been previously described. We herein present a case report of intermittent ureterovesical junction obstruction, characterized by intermittent hydroureteronephrosis on ultrasonography and symptoms of flank/abdominal pain, nausea and vomiting.
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What should we include in a cultural competence curriculum? An emerging formative evaluation process to foster curriculum development.
Acad Med
PUBLISHED: 01-21-2011
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To identify, prioritize, and organize components of a cultural competence curriculum to address disparities in cardiovascular disease.
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Use of ecological momentary assessment to guide curricular change in graduate medical education.
J Grad Med Educ
PUBLISHED: 01-03-2011
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To assess whether a novel evaluation tool could guide curricular change in an internal medicine residency program.
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The Penicillium chrysogenum extracellular proteome. Conversion from a food-rotting strain to a versatile cell factory for white biotechnology.
Mol. Cell Proteomics
PUBLISHED: 09-07-2010
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The filamentous fungus Penicillium chrysogenum is well-known by its ability to synthesize ?-lactam antibiotics as well as other secondary metabolites. Like other filamentous fungi, this microorganism is an excellent host for secretion of extracellular proteins because of the high capacity of its protein secretion machinery. In this work, we have characterized the extracellular proteome reference map of P. chrysogenum Wisconsin 54-1255 by two-dimensional gel electrophoresis. This method allowed the correct identification of 279 spots by peptide mass fingerprinting and tandem MS. These 279 spots included 328 correctly identified proteins, which corresponded to 131 different proteins and their isoforms. One hundred and two proteins out of 131 were predicted to contain either classical or nonclassical secretion signal peptide sequences, providing evidence of the authentic extracellular location of these proteins. Proteins with higher representation in the extracellular proteome were those involved in plant cell wall degradation (polygalacturonase, pectate lyase, and glucan 1,3-?-glucosidase), utilization of nutrients (extracellular acid phosphatases and 6-hydroxy-d-nicotine oxidase), and stress response (catalase R). This filamentous fungus also secretes enzymes specially relevant for food industry, such as sulfydryl oxidase, dihydroxy-acid dehydratase, or glucoamylase. The identification of several antigens in the extracellular proteome also highlights the importance of this microorganism as one of the main indoor allergens. Comparison of the extracellular proteome among three strains of P. chrysogenum, the wild-type NRRL 1951, the Wis 54-1255 (an improved, moderate penicillin producer), and the AS-P-78 (a penicillin high-producer), provided important insights to consider improved strains of this filamentous fungus as versatile cell-factories of interest, beyond antibiotic production, for other aspects of white biotechnology.
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Is physician engagement with Web-based CME associated with patients baseline hemoglobin A1c levels? The Rural Diabetes Online Care study.
Acad Med
PUBLISHED: 08-26-2010
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To investigate the association between physician participants levels of engagement in a Web-based educational intervention and their patients baseline diabetes measures.
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Evaluation of gel spun silk-based biomaterials in a murine model of bladder augmentation.
Biomaterials
PUBLISHED: 07-10-2010
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Currently, gastrointestinal segments are considered the gold standard for bladder reconstructive procedures. However, significant complications including chronic urinary tract infection, metabolic abnormalities, urinary stone formation, bowel dysfunction, and secondary malignancies are associated with this approach. Biomaterials derived from silk fibroin may represent a superior alternative due their robust mechanical properties, biodegradable features, and processing plasticity. In the present study, we evaluated the efficacy of a gel spun silk-based matrix for bladder augmentation in a murine model. Over the course of 70 d implantation period, H&E and Massons trichrome (MTS) analysis revealed that silk matrices were capable of supporting both urothelial and smooth muscle regeneration at the defect site. Prominent uroplakin and contractile protein expression (?-actin, calponin, and SM22?) was evident by immunohistochemical analysis demonstrating maturation of the reconstituted bladder wall compartments. Gel spun silk matrices also elicited a minimal acute inflammatory reaction following 70 d of bladder integration, in contrast to parallel assessments of small intestinal submucosa (SIS) and poly-glycolic acid (PGA) matrices which routinely promoted evidence of fibrosis and chronic inflammatory responses. Voided stain on paper analysis revealed that silk augmented animals displayed similar voiding patterns in comparison to non surgical controls by 42 d of implantation. In addition, cystometric evaluations of augmented bladders at 70 d post-op demonstrated that silk scaffolds supported significant increases in bladder capacity and voided volume while maintaining similar degrees of compliance relative to the control group. These results provide evidence for the utility of gel spun silk-based matrices for functional bladder tissue engineering applications.
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Clinical prediction rule for stratifying risk of pulmonary multidrug-resistant tuberculosis.
PLoS ONE
PUBLISHED: 06-25-2010
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Multidrug-resistant tuberculosis (MDR-TB), resistance to at least isoniazid and rifampin, is a worldwide problem.
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Clinical experience in the management of penile fractures at Hospital Universitario del Valle (Cali--Colombia).
Arch. Esp. Urol.
PUBLISHED: 05-29-2010
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The main objective of this study was to describe the clinical characteristics of patients diagnosed with penile fracture in the Hospital Universitario del Valle (Cali, Colombia).
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CCR2 plays a critical role in dendritic cell maturation: possible role of CCL2 and NF-kappa B.
J. Immunol.
PUBLISHED: 04-19-2010
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We postulated that CCR2-driven activation of the transcription factor NF-kappaB plays a critical role in dendritic cell (DC) maturation (e.g., migration, costimulation, and IL-12p70 production), necessary for the generation of protective immune responses against the intracellular pathogen Leishmania major. Supporting this notion, we found that CCR2, its ligand CCL2, and NF-kappaB were required for CCL19 production and adequate Langerhans cell (LC) migration both ex vivo and in vivo. Furthermore, a role for CCR2 in upregulating costimulatory molecules was indicated by the reduced expression of CD80, CD86, and CD40 in Ccr2(-/-) bone marrow-derived dendritic cells (BMDCs) compared with wild-type (WT) BMDCs. Four lines of evidence suggested that CCR2 plays a critical role in the induction of protective immunity against L. major by regulating IL-12p70 production and migration of DC populations such as LCs. First, compared with WT, Ccr2(-/-) lymph node cells, splenocytes, BMDCs, and LCs produced lower levels of IL-12p70 following stimulation with LPS/IFN-gamma or L. major. Second, a reduced number of LCs carried L. major from the skin to the draining lymph nodes in Ccr2(-/-) mice compared with WT mice. Third, early treatment with exogenous IL-12 reversed the susceptibility to L. major infection in Ccr2(-/-) mice. Finally, disruption of IL-12p70 in radioresistant cells, such as LCs, but not in BMDCs resulted in the inability to mount a fully protective immune response in bone marrow chimeric mice. Collectively, our data point to an important role for CCR2-driven activation of NF-kappaB in the regulation of DC/LC maturation processes that regulate protective immunity against intracellular pathogens.
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All-trans retinoic acid directs urothelial specification of murine embryonic stem cells via GATA4/6 signaling mechanisms.
PLoS ONE
PUBLISHED: 03-12-2010
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The urinary bladder and associated tract are lined by the urothelium, a transitional epithelium that acts as a specialized permeability barrier that protects the underlying tissue from urine via expression of a highly specific group of proteins known as the uroplakins (UP). To date, our understanding of the developmental processes responsible for urothelial differentiation has been hampered due to the lack of suitable models. In this study, we describe a novel in vitro cell culture system for derivation of urothelial cells from murine embryonic stem cells (ESCs) following cultivation on collagen matrices in the presence all trans retinoic acid (RA). Upon stimulation with micromolar concentrations of RA, ESCs significantly downregulated the pluripotency factor OCT-4 but markedly upregulated UP1A, UP1B, UP2, UP3A, and UP3B mRNA levels in comparison to naïve ESCs and spontaneously differentiating controls. Pan-UP protein expression was associated with both p63- and cytokeratin 20-positive cells in discrete aggregating populations of ESCs following 9 and 14 days of RA stimulation. Analysis of endodermal transcription factors such as GATA4 and GATA6 revealed significant upregulation and nuclear enrichment in RA-treated UP2-GFP+ populations. GATA4-/- and GATA6-/- transgenic ESC lines revealed substantial attenuation of RA-mediated UP expression in comparison to wild type controls. In addition, EMSA analysis revealed that RA treatment induced formation of transcriptional complexes containing GATA4/6 on both UP1B and UP2 promoter fragments containing putative GATA factor binding sites. Collectively, these data suggest that RA mediates ESC specification toward a urothelial lineage via GATA4/6-dependent processes.
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DNA topoisomerases in apicomplexan parasites: promising targets for drug discovery.
Proc. Biol. Sci.
PUBLISHED: 03-03-2010
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The phylum Apicomplexa includes a large group of protozoan parasites responsible for a wide range of animal and human diseases. Destructive pathogens, such as Plasmodium falciparum and Plasmodium vivax, causative agents of human malaria, Cryptosporidium parvum, responsible of childhood diarrhoea, and Toxoplasma gondii, responsible for miscarriages and abortions in humans, are frequently associated with HIV immunosuppression in AIDS patients. The lack of effective vaccines, along with years of increasing pressure to eradicate outbreaks with the use of drugs, has favoured the formation of multi-drug resistant strains in endemic areas. Almost all apicomplexan of medical interest contain two endosymbiotic organelles that contain their own mitochondrial and apicoplast DNA. Apicoplast is an attractive target for drug testing because in addition to harbouring singular metabolic pathways absent in the host, it also has its own transcription and translation machinery of bacterial origin. Accordingly, apicomplexan protozoa contain an interesting mixture of enzymes to unwind DNA from eukaryotic and prokaryotic origins. On the one hand, the main mechanism of DNA unwinding includes the scission of one-type I-or both DNA strands-type II eukaryotic topoisomerases, establishing transient covalent bonds with the scissile end. These enzymes are targeted by camptothecin and etoposide, respectively, two natural drugs whose semisynthetic derivatives are currently used in cancer chemotherapy. On the other hand, DNA gyrase is a bacterial-borne type II DNA topoisomerase that operates within the apicoplast and is effectively targeted by bacterial antibiotics like fluoroquinolones and aminocoumarins. The present review is an update on the new findings concerning topoisomerases in apicomplexan parasites and the role of these enzymes as targets for therapeutic agents.
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Recruitment of rural physicians in a diabetes internet intervention study: overcoming challenges and barriers.
J Natl Med Assoc
PUBLISHED: 03-03-2010
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This paper highlights a descriptive study of the challenges and lessons learned in the recruitment of rural primary care physicians into a randomized clinical trial using an Internet-based approach.
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Proteome analysis of the penicillin producer Penicillium chrysogenum: characterization of protein changes during the industrial strain improvement.
Mol. Cell Proteomics
PUBLISHED: 02-12-2010
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Proteomics is a powerful tool to understand the molecular mechanisms causing the production of high penicillin titers by industrial strains of the filamentous fungus Penicillium chrysogenum as the result of strain improvement programs. Penicillin biosynthesis is an excellent model system for many other bioactive microbial metabolites. The recent publication of the P. chrysogenum genome has established the basis to understand the molecular processes underlying penicillin overproduction. We report here the proteome reference map of P. chrysogenum Wisconsin 54-1255 (the genome project reference strain) together with an in-depth study of the changes produced in three different strains of this filamentous fungus during industrial strain improvement. Two-dimensional gel electrophoresis, peptide mass fingerprinting, and tandem mass spectrometry were used for protein identification. Around 1000 spots were visualized by "blue silver" colloidal Coomassie staining in a non-linear pI range from 3 to 10 with high resolution, which allowed the identification of 950 proteins (549 different proteins and isoforms). Comparison among the cytosolic proteomes of the wild-type NRRL 1951, Wisconsin 54-1255 (an improved, moderate penicillin producer), and AS-P-78 (a penicillin high producer) strains indicated that global metabolic reorganizations occurred during the strain improvement program. The main changes observed in the high producer strains were increases of cysteine biosynthesis (a penicillin precursor), enzymes of the pentose phosphate pathway, and stress response proteins together with a reduction in virulence and in the biosynthesis of other secondary metabolites different from penicillin (pigments and isoflavonoids). In the wild-type strain, we identified enzymes to utilize cellulose, sorbitol, and other carbon sources that have been lost in the high penicillin producer strains. Changes in the levels of a few specific proteins correlated well with the improved penicillin biosynthesis in the high producer strains. These results provide useful information to improve the production of many other bioactive secondary metabolites.
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[Euroscore system validation for cardiac surgery in Cordoba city].
Rev Fac Cien Med Univ Nac Cordoba
PUBLISHED: 01-27-2010
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We recommend the use of models to estimate mortality hospital risk in cardiac surgery (CC). The aim of this study was to validate a risk stratification system, widely used as the EuroSCORE (ES), in our institution.
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Characteristics that predict physician participation in a Web-based CME activity: the MI-Plus study.
J Contin Educ Health Prof
PUBLISHED: 12-10-2009
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Physician use of the Internet for practice improvement has increased dramatically over the last decade, but research shows that many physicians choose not to participate. The current study investigated the association of specific physician characteristics with enrollment rates and intensity of participation in a specific Internet-delivered educational intervention to improve care to post-myocardial infarction (MI) patients.
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The Department of Veterans Affairs National Quality Scholars Fellowship Program: experience from 10 years of training quality scholars.
Acad Med
PUBLISHED: 11-27-2009
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The Department of Veterans Affairs (VA) National Quality Scholars Fellowship Program (VAQS) was established in 1998 as a postgraduate medical education fellowship to train physicians in new methods of improving the quality and safety of health care for veterans and the nation. The VAQS curriculum is based on adult learning theory, with a national core curriculum of face-to-face components, technologically mediated distance learning components, and a unique local curriculum that draws from the strengths of regional resources. VAQS has established strong ties with other VA programs. Fellows research and quality improvement projects are integrated with local and regional VA leaders priorities, enhancing the relevance and visibility of the fellows efforts and promoting recruitment of fellows to VA positions. VAQS has enrolled 98 fellows since 1999; 75 have completed the program and 24 are currently enrolled. Fellowship graduates have pursued a variety of career paths: 17% are continuing training (most in VA), 31% hold a VA faculty/staff position, 66% are academic faculty, and 80% conduct clinical or research work related to health care improvement. Graduates have held leadership positions in VA, Department of Defense, academic medicine, and public health agencies. Combining knowledge about the improvement of health care with adult learning strategies, distance learning technologies, face-to-face meetings, local mentorship, and experiential projects has been successful in improving care in VA and preparing physicians to participate in, study, and lead the improvement of health care quality and safety.
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[Prevalence of abnormal coagulation tests in patients who undergo transrectal biopsy of the prostate].
Actas Urol Esp
PUBLISHED: 11-11-2009
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To determine the prevalence of abnormal coagulation tests in patients who undergo transrectal prostate biopsy.
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[TIMI risk score validation for patients with acute coronary syndrome without ST elevation].
Medicina (B Aires)
PUBLISHED: 11-10-2009
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Non-ST elevation acute coronary syndromes (NSTE-ACS) are frequent cause of hospitalization, being responsible for 10-15% of infarcts or deaths per year. The study was designed to analyze 6 months follow-up of cardiovascular events as well as to validate the Thrombolysis in Myocardial Infarction (TIMI) risk score for patients hospitalized for NSTE-ACS. We retrospectively analyzed patients admitted with NSTE-ACS. Telephone follow-up were performed at 6 month. Combination of death, re-admission for acute coronary syndrome and revascularization were considered as end point. Two hundred and four patients were included for the analysis. There were 70.2% males, with a mean age of 64.5 +/- 11.8 years. After the initial evaluation, we diagnosed unstable angina in 34.6% of cases, MI in 38.9% of cases, and 26.4% of patients were categorized as "non coronary chest pain". Applying the TIMI risk score, 52 (25.5%) patients had low risk, 106 (52%) intermediated risk, and 46 (22.5%) high risk. The global mortality was 12.3%. We found a progressively and significant increase in the rate of combined events as the TIMI score increase (p < 0.001). We conclude that in our population, the intermediated and high TIMI risk score was well related to newer cardiovascular events at 6 month follow-up.
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Transcriptional upregulation of four genes of the lysine biosynthetic pathway by homocitrate accumulation in Penicillium chrysogenum: homocitrate as a sensor of lysine-pathway distress.
Microbiology (Reading, Engl.)
PUBLISHED: 08-20-2009
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The lysine biosynthetic pathway has to supply large amounts of alpha-aminoadipic acid for penicillin biosynthesis in Penicillium chrysogenum. In this study, we have characterized the P. chrysogenum L2 mutant, a lysine auxotroph that shows highly increased expression of several lysine biosynthesis genes (lys1, lys2, lys3, lys7). The L2 mutant was found to be deficient in homoaconitase activity since it was complemented by the Aspergillus nidulans lysF gene. We have cloned a gene (named lys3) that complements the L2 mutation by transformation with a P. chrysogenum genomic library, constructed in an autonomous replicating plasmid. The lys3-encoded protein showed high identity to homoaconitases. In addition, we cloned the mutant lys3 allele from the L2 strain that showed a G(1534) to A(1534) point mutation resulting in a Gly(495) to Asp(495) substitution. This mutation is located in a highly conserved region adjacent to two of the three cysteine residues that act as ligands to bind the iron-sulfur cluster required for homoaconitase activity. The L2 mutant accumulates homocitrate. Deletion of the lys1 gene (homocitrate synthase) in the L2 strain prevented homocitrate accumulation and reverted expression levels of the four lysine biosynthesis genes tested to those of the parental prototrophic strain. Homocitrate accumulation seems to act as a sensor of lysine-pathway distress, triggering overexpression of four of the lysine biosynthesis genes.
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Ultrasound versus computerized tomography for evaluating urolithiasis.
J. Urol.
PUBLISHED: 08-19-2009
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We prospectively evaluated the precision of ultrasound and computerized tomography to diagnose urinary stones in children and determined whether these differences in radiological findings have any impact on clinical management.
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Variation in the 4q25 chromosomal locus predicts atrial fibrillation after coronary artery bypass graft surgery.
Circ Cardiovasc Genet
PUBLISHED: 08-02-2009
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Atrial fibrillation (AF) is the most common adverse event following coronary artery bypass graft surgery. A recent study identified chromosome 4q25 variants associated with AF in ambulatory populations. However, their role in postoperative AF is unknown. We hypothesized that genetic variants in the 4q25 chromosomal region are independently associated with postoperative AF after coronary artery bypass graft surgery.
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Regulation and compartmentalization of ?-lactam biosynthesis.
Microb Biotechnol
PUBLISHED: 05-31-2009
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Penicillins and cephalosporins are ?-lactam antibiotics widely used in human medicine. The biosynthesis of these compounds starts by the condensation of the amino acids L-?-aminoadipic acid, L-cysteine and L-valine to form the tripeptide ?-L-?-aminoadipyl-l-cysteinyl-D-valine catalysed by the non-ribosomal peptide ACV synthetase. Subsequently, this tripeptide is cyclized to isopenicillin N that in Penicillium is converted to hydrophobic penicillins, e.g. benzylpenicillin. In Acremonium and in streptomycetes, isopenicillin N is later isomerized to penicillin N and finally converted to cephalosporin. Expression of genes of the penicillin (pcbAB, pcbC, pendDE) and cephalosporin clusters (pcbAB, pcbC, cefD1, cefD2, cefEF, cefG) is controlled by pleitropic regulators including LaeA, a methylase involved in heterochromatin rearrangement. The enzymes catalysing the last two steps of penicillin biosynthesis (phenylacetyl-CoA ligase and isopenicillin N acyltransferase) are located in microbodies, as shown by immunoelectron microscopy and microbodies proteome analyses. Similarly, the Acremonium two-component CefD1-CefD2 epimerization system is also located in microbodies. This compartmentalization implies intracellular transport of isopenicillin N (in the penicillin pathway) or isopenicillin N and penicillin N in the cephalosporin route. Two transporters of the MFS family cefT and cefM are involved in transport of intermediates and/or secretion of cephalosporins. However, there is no known transporter of benzylpenicillin despite its large production in industrial strains.
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Scholarship opportunities for trainees and clinician educators: learning outcomes from a case report writing workshop.
J Gen Intern Med
PUBLISHED: 05-29-2009
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Publishing a case report demonstrates scholarly productivity for trainees and clinician-educators.
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Identifying key components for an effective case report poster: an observational study.
J Gen Intern Med
PUBLISHED: 05-29-2009
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Residents demonstrate scholarly activity by presenting posters at academic meetings. Although recommendations from national organizations are available, evidence identifying which components are most important is not.
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Molecular characterization of a fungal gene paralogue of the penicillin penDE gene of Penicillium chrysogenum.
BMC Microbiol.
PUBLISHED: 05-26-2009
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Penicillium chrysogenum converts isopenicillin N (IPN) into hydrophobic penicillins by means of the peroxisomal IPN acyltransferase (IAT), which is encoded by the penDE gene. In silico analysis of the P. chrysogenum genome revealed the presence of a gene, Pc13g09140, initially described as paralogue of the IAT-encoding penDE gene. We have termed this gene ial because it encodes a protein with high similarity to IAT (IAL for IAT-Like). We have conducted an investigation to characterize the ial gene and to determine the role of the IAL protein in the penicillin biosynthetic pathway.
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The global regulator LaeA controls penicillin biosynthesis, pigmentation and sporulation, but not roquefortine C synthesis in Penicillium chrysogenum.
Biochimie
PUBLISHED: 04-17-2009
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The biosynthesis of the beta-lactam antibiotic penicillin is an excellent model for the study of secondary metabolites produced by filamentous fungi due to the good background knowledge on the biochemistry and molecular genetics of the beta-lactam producing microorganisms. The three genes (pcbAB, pcbC, penDE) encoding enzymes of the penicillin pathway in Penicillium chrysogenum are clustered, but no penicillin pathway-specific regulators have been found in the genome region that contains the penicillin gene cluster. The biosynthesis of this beta-lactam is controlled by global regulators of secondary metabolism rather than by a pathway-specific regulator. In this work we have identified the gene encoding the secondary metabolism global regulator LaeA in P. chrysogenum (PcLaeA), a nuclear protein with a methyltransferase domain. The PclaeA gene is present as a single copy in the genome of low and high-penicillin producing strains and is not located in the 56.8-kb amplified region occurring in high-penicillin producing strains. Overexpression of the PclaeA gene gave rise to a 25% increase in penicillin production. PclaeA knock-down mutants exhibited drastically reduced levels of penicillin gene expression and antibiotic production and showed pigmentation and sporulation defects, but the levels of roquefortine C produced and the expression of the dmaW involved in roquefortine biosynthesis remained similar to those observed in the wild-type parental strain. The lack of effect on the synthesis of roquefortine is probably related to the chromatin arrangement in the low expression roquefortine promoters as compared to the bidirectional pbcAB-pcbC promoter region involved in penicillin biosynthesis. These results evidence that PcLaeA not only controls some secondary metabolism gene clusters, but also asexual differentiation in P. chrysogenum.
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