542 research outputs found

    Bench-to-bedside review: A brief history of clinical acid–base

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    The history of assessing the acid–base equilibrium and associated disorders is intertwined with the evolution of the definition of an acid. In the 1950s clinical chemists combined the Henderson–Hasselbalch equation and the Bronsted–Lowry definition of an acid to produce the current bicarbonate ion-centred approach to metabolic acid–base disorders. Stewart repackaged pre-1950 ideas of acid–base in the late 1970s, including the Van Slyke definition of an acid. Stewart also used laws of physical chemistry to produce a new acid–base approach. This approach, using the strong ion difference (particularly the sodium chloride difference) and the concentration of weak acids (particularly albumin), pushes bicarbonate into a minor role as an acid–base indicator rather than as an important mechanism. The Stewart approach may offer new insights into acid–base disorders and therapies

    Curated Collections for Educators: Eight Key Papers about Feedback in Medical Education

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    Feedback is an essential part of learning, growth, and academic success. Junior faculty members are often unfamiliar with the grounding literature that defines feedback. Many times they receive little education on providing and receiving feedback, resulting in unhelpful "feedback" for both learners and program leadership alike. This article aims to summarize eight key papers on feedback, to outline relevant information for emerging clinician educators, and identify ways to use these resources for the faculty development. In order to generate a list of key papers that describes the importance and significance of feedback, the authors conducted a consensus-building process to identify the top papers. In August and September, 2018, the 2018-2019 Academic Life in Emergency Medicine (ALiEM) Faculty Incubator program discussed the topic of feedback in medical education. A number of papers on the topic was highlighted. This list of papers was further augmented using the suggestions and expertise of guest experts who are leaders in the field of medical education and feedback. The authors also used social media to conduct an open call on Twitter for important papers regarding feedback (utilizing #meded, #Feedback hashtags). Via this process, a list of 88 key papers was identified on the topic of feedback in medical education. After compiling these papers, the authorship group engaged in a modified Delphi approach to build consensus on the top eight papers on feedback. These papers were deemed essential by the authors and have been summarized with respect to their relevance to junior faculty members and to faculty developers. In this manuscript, we present eight key papers addressing feedback in medical education with discussions and applications for junior faculty members and faculty developers. This list of articles that can serve to help junior clinician educators grow in their ability to give effective feedback and also serve as resources upon which senior faculty can design the faculty development sessions

    Modulation and lack of cross-talk between signal transducer and activator of transcription 5 and suppressor of cytokine signaling-3 in insulin and growth hormone signaling in 3T3-L1 adipocytes

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    Objective: To examine the role of signal transducer and activator of transcription (STAT) 5 and suppressor of cytokine signaling (SOCS)-3 in the cross-talk between growth hormone and insulin (INS) signaling in fat cells. Research Methods and Procedures: Fully differentiated 3T3-L1 adipocytes were exposed to INS, growth hormone (GH), or both of these growth factors, and the activation of STAT5 proteins and mitogen-activated protein kinase was examined using phospho-specific antibodies. The induction of SOCS-3 mRNA was assessed by Northern blot analysis. INS-stimulated glucose transport was also measured. Results: We observed that GH, not INS, induced STAT5 activation in adipocytes in a manner that was independent of extracellular signal-regulated kinase (ERK) activation or new protein synthesis. GH strongly induced SOCS-3 mRNA expression, whereas INS had a much less potent effect on SOCS-3 mRNA expression. Because SOCS-3 has been implicated in the attenuation of GH and INS signaling, we examined the cross-talk between these signaling pathways. GH pretreatment of adipocytes inhibited GH signaling. Similarly, INS pretreatment inhibited INS signaling. However, INS did not block the GH-induced activation of STAT5, and GH did not block the INS induction of ERK activity or of increased glucose uptake. We observed that neither new protein synthesis nor activation of ERKs 1 and 2 were required for the inhibition of GH signaling. Discussion: These results demonstrate that blocking the induction of the SOCS-3 protein has no effect on the attenuation of GH signaling and support recent studies suggesting that SOCS proteins have additional functions. In addition, these studies demonstrate that GH-induced SOCS-3 expression is insufficient to inhibit INS-induced glucose uptake in adipocytes. Copyright © 2006 NAASO

    Bench-to-bedside review: Chloride in critical illness

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    Chloride is the principal anion in the extracellular fluid and is the second main contributor to plasma tonicity. Its concentration is frequently abnormal in intensive care unit patients, often as a consequence of fluid therapy. Yet chloride has received less attention than any other ion in the critical care literature. New insights into its physiological roles have emerged together with progress in understanding the structures and functions of chloride channels. In clinical practice, interest in a physicochemical approach to acid-base physiology has directed renewed attention to chloride as a major determinant of acid-base status. It has also indirectly helped to generate interest in other possible effects of disorders of chloraemia. The present review summarizes key aspects of chloride physiology, including its channels, as well as the clinical relevance of disorders of chloraemia. The paper also highlights current knowledge on the impact of different types of intravenous fluids on chloride concentration and the potential effects of such changes on organ physiology. Finally, the review examines the potential intensive care unit practice implications of a better understanding of chloride

    Urinary interleukin-18 does not predict acute kidney injury after adult cardiac surgery: a prospective observational cohort study

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    INTRODUCTION: Urinary interleukin-18 (IL-18) measured during the immediate postoperative period could be a promising predictor of acute kidney injury following adult cardiac surgery. METHODS: In a single-centre prospective observational cohort study, we enrolled 100 adult cardiac surgical patients undergoing cardiopulmonary bypass at a tertiary hospital. We measured the urinary concentration of IL-18 and creatinine preoperatively, on arrival in the intensive care unit, and 24 hours postoperatively. We assessed urinary IL-18 concentration and urinary IL-18/urinary creatinine ratio in relation to the postoperative development of acute kidney injury defined as an increase in serum creatinine of greater than 50% from preoperative to postoperative peak value within 48 hours after surgery. RESULTS: Twenty patients developed acute kidney injury. On arrival in the intensive care unit and at 24 hours postoperatively, urinary IL-18 (median [interquartile range]) was not different in patients who subsequently developed acute kidney injury compared with those who did not: on arrival in the intensive care unit (168 [717] versus 104 [256] pg/mL; P = 0.70) and at 24 hours (195 [483] versus 165 [246] pg/mL; P = 0.47). On arrival in the intensive care unit (area under the curve for the receiver operating characteristic curve [AUC-ROCC] 0.53, 95% confidence interval [CI] 0.38 to 0.68; P = 0.70) and at 24 hours postoperatively (AUC-ROCC 0.55, 95% CI 0.40 to 0.71; P = 0.48), urinary IL-18 was not better than chance in predicting acute kidney injury. All findings were confirmed when urinary IL-18 was adjusted for urinary creatinine. Urinary IL-18 correlated with duration of cardiopulmonary bypass (P < 0.001). CONCLUSION: In adults, early postoperative measurement of urinary IL-18 appears not to be valuable in identifying patients who develop acute kidney injury after cardiac surgery, but rather represents a nonspecific marker of cardiopulmonary bypass-associated systemic inflammation

    Denis Parsons Burkitt (1911-1993)

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    Developing a School Functioning Index for Middle Schools

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    Despite widespread recognition of schools\u27 role in the healthy development of youth, surprisingly little research has examined the relationships between schools\u27 overall functioning and the health‐related behavior of students. School functioning could become an important predictor of students\u27 health‐related behavior and may be amenable to intervention. This paper describes the development and testing of the School Functioning Index (SFI) as a first step in investigating this question. The index was developed for use with middle schools and conceived as a predictor of students\u27 violent behavior, with the potential for extending research applications to additional health and social behaviors. Using social cognitive theory, social ecological theory, and social disorganization theory as guides, three domains were identified to operationalize school functioning and identify candidate SFI items: 1) resources available to the school and students; 2) stability of the school population; and 3) the schools\u27 performance as a socializing agent for students. Data for candidate SFI items were collected from public archives and directly from 16 middle schools participating in a school‐based dietary intervention study. Data collection from schools, particularly concerning student aggressive behavior and disciplinary actions, presented challenges. The final SFI comprised nine items and demonstrated good internal consistency and variability. The SFI was modestly correlated in expected directions with violence and other health behaviors. This work supports the feasibility of combining multiple school‐level indicators to create a measure of overall school functioning. Further investigation of validity and more acceptable data collection methods are warranted

    Influencing healthful food choices in school and home environments: results from the TEENS study.

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    Background. The purpose of this research is to examine the effects of an intervention designed to increase the availability of fruits, vegetables and lower fat foods in homes and schools. This research is part of the TEENS study, a school-based intervention study. Methods. Sixteen schools in Minnesota were recruited to be in the study, and approximately 3600 middle school students in the eight intervention schools were exposed to a multi-component intervention. The TEENS intervention included classroom-based curricula, family newsletters, and changes in the school food environment including increasing more healthful options on a la carte and on the school lunch line. In addition to student-level outcomes, changes in availability of fruits, vegetables, and lower fat snacks in home and school environments were evaluated. The TEENS study was conducted from 1997 to 2000. Results. Parents of students in intervention schools reported making healthier choices when grocery shopping as compared to parents of students in control schools (P = 0.01). No intervention effects were evident from a home food inventory. Compared to control schools, intervention schools offered (P = 0.04) and sold (P = 0.07) a higher proportion of healthier foods on a la carte, but no effects were seen for fruit and vegetables sales as part of the regular meal pattern lunch. Conclusion. Our results show mixed results for positively influencing adolescents\u27 school and home environments

    A Topological Deep Learning Framework for Neural Spike Decoding

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    The brain's spatial orientation system uses different neuron ensembles to aid in environment-based navigation. One of the ways brains encode spatial information is through grid cells, layers of decked neurons that overlay to provide environment-based navigation. These neurons fire in ensembles where several neurons fire at once to activate a single grid. We want to capture this firing structure and use it to decode grid cell data. Understanding, representing, and decoding these neural structures require models that encompass higher order connectivity than traditional graph-based models may provide. To that end, in this work, we develop a topological deep learning framework for neural spike train decoding. Our framework combines unsupervised simplicial complex discovery with the power of deep learning via a new architecture we develop herein called a simplicial convolutional recurrent neural network (SCRNN). Simplicial complexes, topological spaces that use not only vertices and edges but also higher-dimensional objects, naturally generalize graphs and capture more than just pairwise relationships. Additionally, this approach does not require prior knowledge of the neural activity beyond spike counts, which removes the need for similarity measurements. The effectiveness and versatility of the SCRNN is demonstrated on head direction data to test its performance and then applied to grid cell datasets with the task to automatically predict trajectories
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