Knockout of syntaxin-4 in 3T3-L1 adipocytes reveals new insight into GLUT4 trafficking and adiponectin secretion.

Adipocytes are key to metabolic regulation, exhibiting insulin-stimulated glucose transport that is underpinned by the insulin-stimulated delivery of glucose transporter type 4 (SLC2A4, also known and hereafter referred to as GLUT4)-containing vesicles to the plasma membrane where they dock and fuse, and increase cell surface GLUT4 levels. Adipocytokines, such as adiponectin, are secreted via a similar mechanism. We used genome editing to knock out syntaxin-4, a protein reported to mediate fusion between GLUT4-containing vesicles and the plasma membrane in 3T3-L1 adipocytes. Syntaxin-4 knockout reduced insulin-stimulated glucose transport and adiponectin secretion by ∼50% and reduced GLUT4 levels. Ectopic expression of haemagglutinin (HA)-tagged GLUT4 conjugated to GFP showed that syntaxin-4-knockout cells retain significant GLUT4 translocation capacity, demonstrating that syntaxin-4 is dispensable for insulin-stimulated GLUT4 translocation. Analysis of recycling kinetics revealed only a modest reduction in the exocytic rate of GLUT4 in knockout cells, and little effect on endocytosis. These analyses demonstrate that syntaxin-4 is not always rate limiting for GLUT4 delivery to the cell surface. In sum, we show that syntaxin-4 knockout results in reduced insulin-stimulated glucose transport, depletion of cellular GLUT4 levels and inhibition of adiponectin secretion but has only modest effects on the translocation capacity of the cells. This article has an associated First Person interview with Hannah L. Black and Rachel Livingstone, joint first authors of the paper.

Distributed cognition: Theoretical insights and practical applications to health professions education: AMEE Guide No. 159.

Distributed cognition (DCog) is a member of the family of situativity theories that widens the lens of cognition from occurring solely inside the head to being socially, materially and temporally distributed within a dynamic system. The concept of extending the view of cognition to outside the head of a single health professional is relatively new in the healthcare system. DCog has been increasingly used by researchers to describe many ways in which health professionals perform in teams within structured clinical environments to deliver healthcare for patients. In this Guide, we expound ten central tenets of the macro (grand) theory of DCog (1. Cognition is decentralized in a system; 2. The unit of analysis is the system; 3. Cognitive processes are distributed; 4. Cognitive processes emerge from interactions; 5. Cognitive processes are interdependent; 6. Social organization is a cognitive architecture; 7. Division of labour; 8. Social organization is a system of communication; 9. Buffering and filtering; 10. Cognitive processes are encultured) to provide theoretical insights as well as practical applications to the field of health professions education.

Twine virtual patient games as an online resource for undergraduate diabetes acute care education.

BACKGROUND: Virtual patients provide a safe way to simulate authentic clinical practice. Twine is an open-source software that can be used to create intricate virtual patient games, including elements like non-linear free text history taking and time-related changes to the game's narrative. We evaluated the incorporation of Twine virtual patient games into a diabetes acute care online learning package for undergraduate medical students at the University of Glassgow, Scotland. METHODS: Three games were developed using Twine, Wacom Intuous Pro, Autodesk SketchBook, Camtasia Studio, and simulated patients. Online material included three VP games, eight microlectures, and a single best answer multiple choice question quiz. The games were evaluated at Kirkpatrick Level 1 with an acceptability and usability questionnaire. The entire online package was evaluated at Kirkpatrick Level 2 with pre- and post-course multiple choice and confidence questions, with statistical analysis performed using paired t-tests. RESULTS: 122 of approximately 270 eligible students provided information on resource utilisation, with 96% of these students using at least one online resource. 68% of students who returned surveys used at least one VP game. 73 students provided feedback on the VP games they had played, with the majority of median responses being "agree" on positive usability and acceptability statements. The online resources were associated with a mean multiple choice score increase from 4.37 out of 10 to 7.96 out of 10 (p < 0.0001, 95% CI + 2.99 to + 4.20, n = 52) and a mean total confidence score increase from 4.86 out of 10 to 6.70 out of 10 (p < 0.0001, 95% CI + 1.37 to + 2.30, n = 48). CONCLUSIONS: Our VP games were well-received by students and promoted engagement with online material. The package of online material led to statistically significant increases in confidence and knowledge in diabetes acute care outcomes. A blueprint with supporting instructions has now been created to facilitate rapid creation of further games using Twine software.

Virtual Wards: A Rapid Adaptation to Clinical Attachments in MBChB During the COVID-19 Pandemic.

When the COVID-19 pandemic suddenly prevented medical students from attending their clinical attachments, the faculty involved in the third year of medical school (MBChB3) at the University of Glasgow created Virtual Wards. The focus of the Virtual Wards was to continue teaching of clinical reasoning remotely whilst COVID-19 restrictions were in place. Virtual Wards were mapped to the common and important presentations and conditions and provided opportunity for history-taking, clinical examination skills, requesting investigations, interpreting results, diagnosis and management. The Virtual Wards were successful, and further wards were developed the following academic year for MBChB4 students. This chapter describes the theoretical underpinnings of the Virtual Wards and the technological considerations, followed by a description of the Wards themselves. We then analyse an evaluation of the Virtual Wards and provide both a faculty and student perspective. Throughout the chapter, we provide tips for educators developing Virtual Ward environments.

Sharing the Bandwidth in Cognitively Overloaded Teams and Systems: Mechanistic Insights from a Walk on the Wild Side of Clinical Reasoning.

IssuePrevious work from the diagnostic error literature has provided indirect evidence that faulty clinical reasoning may be the most frequent cause of error when attaching a diagnostic label. The precise mechanisms underlying diagnostic error are unclear and continue to be subject to considerable theory informed debate in the clinical reasoning literature. Evidence: We take a theoretical approach to merging these two worlds of literature by first zooming out using distributed cognition as a social cognitive lens (macro theory) to develop a view of the process and outcome of clinical reasoning occurring in the wild - defined as the integrated clinical workplace - the natural habitat of clinicians working within teams. We then zoom in using the novel combination of cognitive load theory and distributed cognition to provide additional theoretical insights into the potential mechanisms of error. Implications: Through the lenses of distributed cognition and cognitive load theory, we can begin to prospectively investigate how cognitive overload is represented and shared within interprofessional teams over time and space and how this influences clinical reasoning performance and leads to error. We believe that this work will help teams manage cognitive load and prevent error.

Metformin and carotid intima-media thickness in never-smokers with type 1 diabetes: The REMOVAL trial.

AIM: To determine whether metformin's effects on carotid artery intima-media thickness (cIMT) in type 1 diabetes differ according to smoking status. METHODS: Regression model effect estimates for the effect of metformin versus placebo (double-blind) on carotid IMT were calculated as a subgroup analysis of the REMOVAL trial. RESULTS: In 428 randomized participants (227 never-smokers, 201 ever-smokers), averaged mean carotid IMT progression (per year) was reduced by metformin versus placebo in never-smokers (-0.012 mm, 95% CI -0.021 to -0.002; p = .0137) but not in ever-smokers (0.003 mm, 95% CI -0.008 to 0.014; p = .5767); and similarly in non-current smokers (-0.008 mm, 95% CI -0.015 to -0.00001; p = .0497) but not in current smokers (0.013 mm, 95% CI -0.007 to 0.032; p = .1887). Three-way interaction terms (treatment*time*smoking status) were significant for never versus ever smoking (p = .0373, prespecified) and non-current versus current smoking (p = .0496, exploratory). Averaged maximal carotid IMT progression (per year) was reduced by metformin versus placebo in never-smokers (-0.020 mm, 95% CI -0.034 to -0.006; p = .0067) but not in ever-smokers (-0.006 mm, 95% CI -0.020 to 0.008; p = .4067), although this analysis was not supported by a significant three-way interaction term. CONCLUSIONS: This subgroup analysis of the REMOVAL trial provides additional support for a potentially wider role of adjunct metformin therapy in cardiovascular risk management in type 1 diabetes, particularly for individuals who have never smoked cigarettes.

Time in Range as a Research Outcome Measure.

Time in range (TIR) is gaining ground as an outcome measure in type 1 diabetes trials. However, inclusion of TIR raises several issues for trial design. In this article, the authors begin by defining TIR and describing the current international consensus around TIR targets. They then expand on evidence for the validity of TIR as a primary clinical trial outcome before concluding with some practical, ethical, and logistical implications.

Virtual Patients in Health Professions Education.

Health care professionals must not only have knowledge, but also be able to organise, synthesise and apply this knowledge in such a way that it promotes the development of clinical reasoning. Panels of Virtual patients (VPs) are widely being used in health professions education to facilitate the development of clinical reasoning. VPs can also be used to teach wider educational outcomes such as communication skills, resource utilisation and longitudinal patient care. This chapter will define virtual patients and examine the evidence behind their use in health professions learning and teaching. The chapter will discuss virtual patient design, such as gamification. Finally, the chapter will discuss where this pedagogical innovation is best integrated into assessment and potential barriers to implementation into existing curricula.

Cardiovascular benefits of GLP-1 agonists in type 2 diabetes: a comparative review.

Type 2 diabetes (T2D) carries risks of both cardiovascular (CV) (myocardial infarction, stroke, and peripheral vascular disease) and microvascular (retinopathy/nephropathy/neuropathy) complications. Glucose-lowering is an effective strategy for preventing microvascular complications, but the extent to which it can reduce CV complications is less certain. Glucagon-like peptide-1 (GLP-1) agonists are potent glucose-lowering agents but also have potentially beneficial effects on other traditional (body weight, blood pressure (BP), and LDL cholesterol) and non-traditional risk factors (low grade inflammation and endothelial dysfunction). The results of four large CV outcome trials with GLP-1 agonists are now available. These have compared lixisenatide (ELIXA), liraglutide (LEADER), semaglutide (SUSTAIN-6), and long-acting exenatide (EXSCEL) with placebo and standard of care over 2-4 years; four others (including with dulaglutide and albiglutide) are ongoing. LEADER and SUSTAIN-6 have demonstrated reductions in rates of major adverse CV events with active GLP-1 treatment but ELIXA and EXSCEL have not. In this review, we discuss the mechanisms by which GLP-1 receptor agonists act on the CV system and the design and conduct of these trials. Contrary to the assertions that (a) all GLP-1 agonists reduce CV disease in T2D but to different extents or (b) the magnitude of CV protection is predominantly related to glucose-lowering, we argue that CV benefit is specific to agents that provide longer acting agonism at the GLP-1 receptor. The mechanisms involve reduction in body weight and BP, and lowering of LDL-cholesterol and glucose, but pleiotropic effects-including suppression of low grade inflammation, vasodilation, and natriuresis-are also likely relevant.

A new perspective on metformin therapy in type 1 diabetes.

Metformin is quite frequently used off-label in type 1 diabetes to limit insulin dose requirement. Guidelines recommend that it can improve glucose control in those who are overweight and obese but evidence in support of this is limited. Recently-published findings from the REducing with MetfOrmin Vascular Adverse Lesions (REMOVAL) trial suggest that metformin therapy in type 1 diabetes can reduce atherosclerosis progression, weight and LDL-cholesterol levels. This provides a new perspective on metformin therapy in type 1 diabetes and suggests a potential role for reducing the long-term risk of cardiovascular disease.

A theory to explain some physiological effects of the infrasonic emissions at some wind farm sites.

For at least four decades, there have been reports in scientific literature of people experiencing motion sickness-like symptoms attributed to low-frequency sound and infrasound. In the last several years, there have been an increasing number of such reports with respect to wind turbines; this corresponds to wind turbines becoming more prevalent. A study in Shirley, WI, has led to interesting findings that include: (1) To induce major effects, it appears that the source must be at a very low frequency, about 0.8 Hz and below with maximum effects at about 0.2 Hz; (2) the largest, newest wind turbines are moving down in frequency into this range; (3) the symptoms of motion sickness and wind turbine acoustic emissions "sickness" are very similar; (4) and it appears that the same organs in the inner ear, the otoliths may be central to both conditions. Given that the same organs may produce the same symptoms, one explanation is that the wind turbine acoustic emissions may, in fact, induce motion sickness in those prone to this affliction.

Developing a universal reading comprehension intervention for mainstream primary schools within areas of social deprivation for children with and without language-learning impairment: a feasibility study.

BACKGROUND: Some children in areas of social deprivation in Scotland have lower reading attainment than neighbouring children in less deprived areas, and some of these also have lower spoken language comprehension skills than expected by assessment norms. There is a need to develop effective reading comprehension interventions that fit easily into the school curriculum and can benefit all pupils. A feasibility study of reading comprehension strategies with existing evidence of efficacy was undertaken in three mainstream primary schools within an area of social deprivation in west central Scotland, to decide whether further investigation of this intervention was warranted. AIMS: Aims were to measure comprehension of spoken language and reading via standardised assessments towards the beginning of the school year (T1) in mainstream primary school classrooms within an area of social deprivation; to have teachers introduce previously-validated text comprehension strategies, and to measure change in reading comprehension outcome measures towards the end of the year (T2). METHODS & PROCEDURES: A pre- and post-intervention cohort design was used. Reading comprehension strategies were introduced to staff in participating schools and used throughout the school year as part of on-going reading instruction. Spoken language comprehension was measured by TROG-2 at T1, and reading progress by score changes from T1 to T2 on the WIAT-II(UK) -T reading comprehension scale. OUTCOMES & RESULTS: Forty-seven pupils in five classes in three primary schools took part: 38% had TROG-2 scores below the 10(th) centile. As a group, children made good reading comprehension progress, with a medium effect size of 0.46. Children with TROG-2 scores below the 10(th) centile had lower mean reading scores than others at T1 and T2, although with considerable overlap. However, TROG-2 did not make a unique contribution to reading progress: children below the 10(th) centile made as much progress as other children. The intervention was welcomed by schools, and the measure of reading comprehension proved responsive to change. CONCLUSIONS: The outcomes suggest the reading intervention may be effective for children with and without spoken language comprehension difficulties, and warrants further investigation in larger, controlled, studies.

Modeling the impact of prevention policies on future diabetes prevalence in the United States: 2010-2030.

BACKGROUND: Although diabetes is one of the most costly and rapidly increasing serious chronic diseases worldwide, the optimal mix of strategies to reduce diabetes prevalence has not been determined. METHODS: Using a dynamic model that incorporates national data on diabetes prevalence and incidence, migration, mortality rates, and intervention effectiveness, we project the effect of five hypothetical prevention policies on future US diabetes rates through 2030: 1) no diabetes prevention strategy; 2) a "high-risk" strategy, wherein adults with both impaired fasting glucose (IFG) (fasting plasma glucose of 100-124 mg/dl) and impaired glucose tolerance (IGT) (2-hour post-load glucose of 141-199 mg/dl) receive structured lifestyle intervention; 3) a "moderate-risk" strategy, wherein only adults with IFG are offered structured lifestyle intervention; 4) a "population-wide" strategy, in which the entire population is exposed to broad risk reduction policies; and 5) a "combined" strategy, involving both the moderate-risk and population-wide strategies. We assumed that the moderate- and high-risk strategies reduce the annual diabetes incidence rate in the targeted subpopulations by 12.5% through 2030 and that the population-wide approach would reduce the projected annual diabetes incidence rate by 2% in the entire US population. RESULTS: We project that by the year 2030, the combined strategy would prevent 4.6 million incident cases and 3.6 million prevalent cases, attenuating the increase in diabetes prevalence by 14%. The moderate-risk approach is projected to prevent 4.0 million incident cases, 3.1 million prevalent cases, attenuating the increase in prevalence by 12%. The high-risk and population approaches attenuate the projected prevalence increases by 5% and 3%, respectively. Even if the most effective strategy is implemented (the combined strategy), our projections indicate that the diabetes prevalence rate would increase by about 65% over the 23 years (i.e., from 12.9% in 2010 to 21.3% in 2030). CONCLUSIONS: While implementation of appropriate diabetes prevention strategies may slow the rate of increase of the prevalence of diabetes among US adults through 2030, the US diabetes prevalence rate is likely to increase dramatically over the next 20 years. Demand for health care services for people with diabetes complications and diabetes-related disability will continue to grow, and these services will need to be strengthened along with primary diabetes prevention efforts.

Respondents' answers to community attitudinal surveys represent impressions of soundscapes and not merely reactions to the physical noise.

Noise dose as a sole independent variable accounts only for less than half of the variance in community response data. Non-acoustic factors, such as attitude to the noise source identified by Job [(1988). J. Acoust. Soc. Am. 83(3), 991-1001] and others, reduce the unexplained variance. This paper suggests that non-acoustic factors reflect the context in which the sonic environment is perceived; hence, these factors constitute the judgments of a soundscape. Fidell et al. [(2011). J. Acoust. Soc. Am. 130(2), 791-806] show that a "community tolerance level" (CTL) is a one-number, community-specific, independent variable that represents the aggregate influence on annoyance judgments of all non-acoustic influences. Taken together these findings suggest that: (i) CTL is a one-number quantification of a soundscape, and (ii) a soundscape can be quantified by a single, numeric variable. It follows, if one can predict or calculate the single numeric quantification of a soundscape, that number will be the CTL. These results can only be true for a soundscape judged on the basis of annoyance. Virtually no data exist for which the respondents even had the possibility to rate the sonic environment positively, i.e., pleasing, so the application of CTL to soundscapes judged positively is not clear.

Small area variation in diabetes prevalence in Puerto Rico.

OBJECTIVE: To estimate the 2009 prevalence of diagnosed diabetes in Puerto Rico among adults ≥ 20 years of age in order to gain a better understanding of its geographic distribution so that policymakers can more efficiently target prevention and control programs. METHODS: A Bayesian multilevel model was fitted to the combined 2008-2010 Behavioral Risk Factor Surveillance System and 2009 United States Census data to estimate diabetes prevalence for each of the 78 municipios (counties) in Puerto Rico. RESULTS: The mean unadjusted estimate for all counties was 14.3% (range by county, 9.9%-18.0%). The average width of the confidence intervals was 6.2%. Adjusted and unadjusted estimates differed little. CONCLUSIONS: These 78 county estimates are higher on average and showed less variability (i.e., had a smaller range) than the previously published estimates of the 2008 diabetes prevalence for all United States counties (mean, 9.9%; range, 3.0%-18.2%).

New approach to undergraduate quality improvement.

BACKGROUND: While quality improvement (QI) is an essential component to modern day clinical practice, some foundation doctors fail to engage. This is compounded by a lack of formalised undergraduate QI teaching. We trial an undergraduate active learning workshop and evaluate it using a concurrent triangulation mixed methods design. APPROACH: We constructed a 2-hour interactive QI workshop utilising near-peer educators for third year undergraduate medical students. Our workshop demonstrated an exemplary project and a template featuring evidenced-based QI tools to grasp key concepts. Informal support was provided for student QI projects, undertaken in small peer groups. Utility was assessed using linked pre-and-post event questionnaires with Likert scales, free text thematic analysis and project completion rates. EVALUATION: We recruited 74 students to attend our workshops delivered over 3 months. We achieved high event satisfaction and significant improvements on baseline confidence. Free text comments suggested students perceive QI as an important part of the undergraduate curriculum, described barriers to engagement and the value they place on project autonomy. The workshop eased student feelings of anxiety and intimidation regarding change ideas. Nine projects were completed with one winning a poster prize at a regional conference. IMPLICATIONS: We demonstrate a popular resource light model that can be scaled up to a variety of centres. Targeting QI teaching at the undergraduate level may be instrumental in developing QI culture in health care systems and address barriers to postgraduate involvement. Our study furthers the understanding of undergraduate students' perspectives of QI and demand for further sessions.

Reframing context specificity in team diagnosis using the theory of distributed cognition.

Context specificity refers to the vexing phenomenon whereby a physician can see two patients with the same presenting complaint, identical history and physical examination findings, but due to specific situational (contextual) factors arrives at two different diagnostic labels. Context specificity remains incompletely understood and undoubtedly leads to unwanted variance in diagnostic outcomes. Previous empirical work has demonstrated that a variety of contextual factors impacts clinical reasoning. These findings, however, have largely focused on the individual clinician; here we broaden this work to reframe context specificity in relation to clinical reasoning by an internal medicine rounding team through the lens of Distributed Cognition (DCog). In this model, we see how meaning is distributed amongst the different members of a rounding team in a dynamic fashion that evolves over time. We describe four different ways in which context specificity plays out differently in team-based clinical care than for a single clinician. While we use examples from internal medicine, we believe that the concepts we present apply equally to other specialties and fields in health care.

Phosphorylation of Syntaxin 4 by the Insulin Receptor Drives Exocytic SNARE Complex Formation to Deliver GLUT4 to the Cell Surface.

A major consequence of insulin binding its receptor on fat and muscle cells is the stimulation of glucose transport into these tissues. This is achieved through an increase in the exocytic trafficking rate of the facilitative glucose transporter GLUT4 from intracellular stores to the cell surface. Delivery of GLUT4 to the cell surface requires the formation of functional SNARE complexes containing Syntaxin 4, SNAP23, and VAMP2. Insulin stimulates the formation of these complexes and concomitantly causes phosphorylation of Syntaxin 4. Here, we use a combination of biochemistry and cell biological approaches to provide a mechanistic link between these observations. We present data to support the hypothesis that Tyr-115 and Tyr-251 of Syntaxin 4 are direct substrates of activated insulin receptors, and that these residues modulate the protein's conformation and thus regulate the rate at which Syntaxin 4 forms SNARE complexes that deliver GLUT4 to the cell surface. This report provides molecular details on how the cell regulates SNARE-mediated membrane traffic in response to an external stimulus.