13,939 research outputs found

    Inefficiency in the Post Anesthesia Care Unit: A Quality Improvement Initiative

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    Background: The post anesthesia care unit (PACU) is a busy environment in which nurses communicate with patients, family members, and a large team of perioperative professionals. PACU nurses were experiencing an unmanageable number of work interruptions due to a higher patient census which increased the daily surgical caseload. Aim: The purpose of this project was to improve efficiency and nurses’ job satisfaction by making work interruptions manageable in the PACU. Methods: Based on Kotter’s Change Theory, a quality improvement initiative was implemented using a change in the communication process. Qualitative and quantitative data was gathered in the PACU and on other units with the intervention roll-out. A pre and post-intervention survey was used to evaluate work interruptions and their effects experienced by nurses in the PACU environment. Results: The use of communication technology impacted work interruptions, but not significantly enough to improve nursing efficiency and nurse satisfaction in the PACU. Conclusion and Implications for CNL® Practice: The next step is to recommend adding a CNL® as a surgical nurse liaison (SNL) to the perioperative team. Ideally, a CNL® with excellent communication and quality improvement skills will exemplify the roles of lateral integrator and patient advocate to improve efficiency. This physical solution, coupled with the communicative technology tool being widely integrated to all members of the perioperative team is expected to influence work interruptions and improve nurse satisfaction more dramatically

    The Garden of the Heart: HeartMath - The New Biotechnology for Treating Children with ADD/ADHD and Arrhythmia

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    This article gives a practitioner's account of her success using HeartMath's techniques and emWave(R) PC heart rhythm coherence feedback system in treating children with AD/HD. Dr. St. Martin's report describes how she helped nearly 400 children eliminate their need for medication using the emWave(R) PC and HeartMath tools

    Insights Into the Carboxyltransferase Reaction of Pyruvate Carboxylase From the Structures of Bound Product and Intermediate Analogs

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    Pyruvate carboxylase (PC) is a biotin-dependent enzyme that catalyzes the MgATP- and bicarbonate-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in central metabolism. The carboxyltransferase (CT) domain of PC catalyzes the transfer of a carboxyl group from carboxybiotin to the accepting substrate, pyruvate. It has been hypothesized that the reactive enolpyruvate intermediate is stabilized through a bidentate interaction with the metal ion in the CT domain active site. Whereas bidentate ligands are commonly observed in enzymes catalyzing reactions proceeding through an enolpyruvate intermediate, no bidentate interaction has yet been observed in the CT domain of PC. Here, we report three X-ray crystal structures of the Rhizobium etli PC CT domain with the bound inhibitors oxalate, 3-hydroxypyruvate, and 3-bromopyruvate. Oxalate, a stereoelectronic mimic of the enolpyruvate intermediate, does not interact directly with the metal ion. Instead, oxalate is buried in a pocket formed by several positively charged amino acid residues and the metal ion. Furthermore, both 3-hydroxypyruvate and 3-bromopyruvate, analogs of the reaction product oxaloacetate, bind in an identical manner to oxalate suggesting that the substrate maintains its orientation in the active site throughout catalysis. Together, these structures indicate that the substrates, products and intermediates in the PC-catalyzed reaction are not oriented in the active site as previously assumed. The absence of a bidentate interaction with the active site metal appears to be a unique mechanistic feature among the small group of biotin-dependent enzymes that act on α-keto acid substrates

    A Substrate-induced Biotin Binding Pocket in the Carboxyltransferase Domain of Pyruvate Carboxylase

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    Biotin-dependent enzymes catalyze carboxyl transfer reactions by efficiently coordinating multiple reactions between spatially distinct active sites. Pyruvate carboxylase (PC), a multifunctional biotin-dependent enzyme, catalyzes the bicarbonate- and MgATP-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in mammalian tissues. To complete the overall reaction, the tethered biotin prosthetic group must first gain access to the biotin carboxylase domain and become carboxylated and then translocate to the carboxyltransferase domain, where the carboxyl group is transferred from biotin to pyruvate. Here, we report structural and kinetic evidence for the formation of a substrate-induced biotin binding pocket in the carboxyltransferase domain of PC from Rhizobium etli. Structures of the carboxyltransferase domain reveal that R. etli PC occupies a symmetrical conformation in the absence of the biotin carboxylase domain and that the carboxyltransferase domain active site is conformationally rearranged upon pyruvate binding. This conformational change is stabilized by the interaction of the conserved residues Asp590 and Tyr628 and results in the formation of the biotin binding pocket. Site-directed mutations at these residues reduce the rate of biotin-dependent reactions but have no effect on the rate of biotin-independent oxaloacetate decarboxylation. Given the conservation with carboxyltransferase domains in oxaloacetate decarboxylase and transcarboxylase, the structure-based mechanism described for PC may be applicable to the larger family of biotin-dependent enzymes

    Writing Assignments with a Metacognitive Component Enhance Learning in a Large Introductory Biology Course

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    Writing assignments, including note taking and written recall, should enhance retention of knowledge, whereas analytical writing tasks with metacognitive aspects should enhance higher-order thinking. In this study, we assessed how certain writing-intensive “interventions,” such as written exam corrections and peer-reviewed writing assignments using Calibrated Peer Review and including a metacognitive component, improve student learning. We designed and tested the possible benefits of these approaches using control and experimental variables across and between our three-section introductory biology course. Based on assessment, students who corrected exam questions showed significant improvement on postexam assessment compared with their nonparticipating peers. Differences were also observed between students participating in written and discussion-based exercises. Students with low ACT scores benefited equally from written and discussion-based exam corrections, whereas students with midrange to high ACT scores benefited more from written than discussion-based exam corrections. Students scored higher on topics learned via peer-reviewed writing assignments relative to learning in an active classroom discussion or traditional lecture. However, students with low ACT scores (17–23) did not show the same benefit from peer-reviewed written essays as the other students. These changes offer significant student learning benefits with minimal additional effort by the instructors

    Inhibitors of Pyruvate Carboxylase

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    This review aims to discuss the varied types of inhibitors of biotin-dependent carboxylases, with an emphasis on the inhibitors of pyruvate carboxylase. Some of these inhibitors are physiologically relevant, in that they provide ways of regulating the cellular activities of the enzymes e.g. aspartate and prohibitin inhibition of pyruvate carboxylase. Most of the inhibitors that will be discussed have been used to probe various aspects of the structure and function of these enzymes. They target particular parts of the structure e.g. avidin – biotin, FTP – ATP binding site, oxamate – pyruvate binding site, phosphonoacetate – binding site of the putative carboxyphosphate intermediate

    All for One and One for All! Disparity Between Overall Crew’s and Individual Rowers’ Pacing Strategies During Rowing

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    Purpose: This study examined individual contributions to overall pacing strategy during 2- and 5-km rowing trials in a cox-less-4 boat. Methods: A crew of 4 male rowers performed maximal-effort on-water trials over 2 and 5 km, and power output during every individual stroke was measured for each crew member. Mean overall boat and individual rower stroke power were calculated for each 25% epoch (25% of total strokes taken), and power for each individual epoch was calculated as a percentage of mean power maintained over the entire distance. The coefficient of variation was used to determine stroke-to-stroke and epoch-to-epoch variability for individual rowers and the overall boat. Results: In both trials, the overall pacing strategy consisted of a high power output in the initial 25% that decreased in the middle 50% and increased again in the final 25%. However, individual rower data indicate wide variation in individual power profiles that did not always mimic the overall boat profile. Conclusions: This study demonstrates that overall boat power profiles during 2- and 5-km rowing trials are similar to velocity profiles previously reported for individual ergometry and on-water racing events. However, this over-all profile is achieved despite considerable variation in individual rower profiles. Further research is warranted to determine the mechanisms through which individual contributions to overall pacing strategy are regulated and the effectiveness or oth-erwise of seemingly disparate individual strategies on overall performance

    Allosteric Regulation Alters Carrier Domain Translocation in Pyruvate Carboxylase

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    Pyruvate carboxylase (PC) catalyzes the ATP-dependent carboxylation of pyruvate to oxaloacetate. The reaction occurs in two separate catalytic domains, coupled by the long-range translocation of a biotinylated carrier domain (BCCP). Here, we use a series of hybrid PC enzymes to examine multiple BCCP translocation pathways in PC. These studies reveal that the BCCP domain of PC adopts a wide range of translocation pathways during catalysis. Furthermore, the allosteric activator, acetyl CoA, promotes one specific intermolecular carrier domain translocation pathway. These results provide a basis for the ordered thermodynamic state and the enhanced carboxyl group transfer efficiency in the presence of acetyl CoA, and reveal that the allosteric effector regulates enzyme activity by altering carrier domain movement. Given the similarities with enzymes involved in the modular synthesis of natural products, the allosteric regulation of carrier domain movements in PC is likely to be broadly applicable to multiple important enzyme systems

    Inactivation of Mandelate Racemase by 3-Hydroxypyruvate Reveals a Potential Mechanistic Link between Enzyme Superfamilies

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    Mandelate racemase (MR), a member of the enolase superfamily, catalyzes the Mg2+-dependent interconversion of the enantiomers of mandelate. Several α-keto acids are modest competitive inhibitors of MR [e.g., mesoxalate (Ki = 1.8 ± 0.3 mM) and 3-fluoropyruvate (Ki = 1.3 ± 0.1 mM)], but, surprisingly, 3-hydroxypyruvate (3-HP) is an irreversible, time-dependent inhibitor (kinact/KI = 83 ± 8 M–1 s–1). Protection from inactivation by the competitive inhibitor benzohydroxamate, trypsinolysis and electrospray ionization tandem mass spectrometry analyses, and X-ray crystallographic studies reveal that 3-HP undergoes Schiff-base formation with Lys 166 at the active site, followed by formation of an aldehyde/enol(ate) adduct. Such a reaction is unprecedented in the enolase superfamily and may be a relic of an activity possessed by a promiscuous progenitor enzyme. The ability of MR to form and deprotonate a Schiff-base intermediate furnishes a previously unrecognized mechanistic link to other α/β-barrel enzymes utilizing Schiff-base chemistry and is in accord with the sequence- and structure-based hypothesis that members of the metal-dependent enolase superfamily and the Schiff-base-forming N-acetylneuraminate lyase superfamily and aldolases share a common ancestor

    Reflections, Relationships and Art Class

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    My homeroom class was 8H. At that time the district grouped students homogeneously by rank or GPA. The “lowest” ranking class was 8H and they were mine. I remember the first day I met them, I was full of knowledge after completing my Master of Art Education just a few months before. I knew just what to do, just what to say. Undoubtedly, the students would love and respect me, and I would inspire them and teach them to love art. They would use art as another language for learning, I would differentiate to meet their needs and identify their “intelligence” based on Howard Gardner’s work (I had his book handy, just in case!). They would become lifelong learners--, after all this was all part of my newly developed teaching philosophy. Students began filtering into the room. “Who the “f” are you?” some of them asked. Most of them ignored me. Some brought coffee and snacks, one sat under my back table, a couple on the window stills, and a few quietly sat at their desks. I introduced myself to the kids that were listening, I tried to engage with kids that weren’t and somehow, I got through it. It was the longest 15 minutes of my life. I knew right away that I was completely unprepared for these circumstances. I felt like an impostor. Although I lived in the same city they did, I went to private schools. I was a 35- year-old white woman, in a racially and ethnically diverse school, with no, “street cred” as my students freely told me. I needed to figure out how to earn their trust and respect, and I needed to do it immediately
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