Hepatic glucose uptake and disposition during short-term high-fat vs. high-fructose feeding

In dogs consuming a high-fat and -fructose diet (52 and 17% of total energy, respectively) for 4 wk, hepatic glucose uptake (HGU) in response to hyperinsulinemia, hyperglycemia, and portal glucose delivery is markedly blunted with reduction in glucokinase (GK) protein and glycogen synthase (GS) activity. The present study compared the impact of selective increases in dietary fat and fructose on liver glucose metabolism. Dogs consumed weight-maintaining chow (CTR) or hypercaloric high-fat (HFA) or high-fructose (HFR) diets diet for 4 wk before undergoing clamp studies with infusion of somatostatin and intraportal insulin (3–4 times basal) and glucagon (basal). The hepatic glucose load (HGL) was doubled during the clamp using peripheral vein (Pe) glucose infusion in the first 90 min (P1) and portal vein (4 mg·kg−1·min−1) plus Pe glucose infusion during the final 90 min (P2). During P2, HGU was 2.8 ± 0.2, 1.0 ± 0.2, and 0.8 ± 0.2 mg·kg−1·min−1 in CTR, HFA, and HFR, respectively (P < 0.05 for HFA and HFR vs. CTR). Compared with CTR, hepatic GK protein and catalytic activity were reduced (P < 0.05) 35 and 56%, respectively, in HFA, and 53 and 74%, respectively, in HFR. Liver glycogen concentrations were 20 and 38% lower in HFA and HFR than CTR (P < 0.05). Hepatic Akt phosphorylation was decreased (P < 0.05) in HFA (21%) but not HFR. Thus, HFR impaired hepatic GK and glycogen more than HFA, whereas HFA reduced insulin signaling more than HFR. HFA and HFR effects were not additive, suggesting that they act via the same mechanism or their effects converge at a saturable step

MedTalks: developing teaching abilities and experience in undergraduate medical students

Objectives: According to the CanMEDS’ Scholar competency, physicians are expected to facilitate the learning of colleagues, patients and other health professionals. However, most medical students are not provided with formal opportunities to gain teaching experience with objective feedback. Methods: To address this, the University’s Medical Education Interest Group (MEIG) created a pilot teaching program in January 2015 entitled ‘MedTalks’. Four 3-hour sessions were held at the University Faculty of Medicine, where first and second year medical students taught clinically oriented topics to undergraduate university students. Each extracurricular session included three 30-minute content lectures, and a 90-minute small group session on physical examination skills. Each medical student-teacher received formal feedback from undergraduate students and from faculty educators regarding teaching style, communication abilities, and professionalism. In addition, medical student-teachers self-evaluated their own teaching experience. Results: Over 50 medical students from the University participated as medical student-teachers. Based on quantitative and qualitative evaluation surveys, 100% of medical students agreed that MedTalks was a useful way to develop teaching skills and 92% gained a greater confidence in individual teaching capabilities, based largely on the opportunity to gain experience (with feedback) in teaching roles. Conclusions: A program designed to give medical students multi-source teaching experience (lecture- and small group-based) and feedback on their teaching (from learners and Faculty observers, in addition to their own self-reflection) can improve medical student confidence and enthusiasm towards teaching. Future studies will clarify if medical student self-perceived enhancements in teaching ability can be corroborated by independent (Faculty, learner) observations of future teaching activity

Suppression of Na+/K+-ATPase activity during estivation in the land snail Otala lactea

Entry into the hypometabolic state of estivation requires a coordinated suppression of the rate of cellular ATP turnover, including both ATP-generating and ATP-consuming reactions. As one of the largest consumers of cellular ATP, the plasma membrane Na+/K+-ATPase is a potentially key target for regulation during estivation. Na+/K+-ATPase was investigated in foot muscle and hepatopancreas of the land snail Otala lactea, comparing active and estivating states. In both tissues enzyme properties changed significantly during estivation: maximal activity was reduced by about one-third, affinity for Mg.ATP was reduced (Km was 40% higher), and activation energy (derived from Arrhenius plots) was increased by ∼45%. Foot muscle Na+/K+-ATPase from estivated snails also showed an 80% increase in Km Na+ and a 60% increase in Ka Mg2+ as compared with active snails, whereas hepatopancreas Na+/K+-ATPase showed a 70% increase in I50 K+ during estivation. Western blotting with antibodies recognizing the alpha subunit of Na+/K+-ATPase showed no change in the amount of enzyme protein during estivation. Instead, the estivation-responsive change in Na+/K+-ATPase activity was linked to posttranslational modification. In vitro incubations manipulating endogenous kinase and phosphatase activities indicated that Na+/K+-ATPase from estivating snails was a high phosphate, low activity form, whereas dephosphorylation returned the enzyme to a high activity state characteristic of active snails. Treatment with protein kinases A, C or G could all mediate changes in enzyme properties in vitro that mimicked the effect of estivation, whereas treatments with protein phosphatase 1 or 2A had the opposite effect. Reversible phosphorylation control of Na+/K+-ATPase can provide the means of coordinating ATP use by this ion pump with the rates of ATP generation by catabolic pathways in estivating snails

MEDTalks: a student-driven program to enhance undergraduate student understanding and interest in medical schools in Canada

The 2018 MEDTalks program consisted of 5 sessions (interviewing skills, the musculoskeletal system, psychiatry, cardiology, and respirology) and ran between January and April 2018. Upon completion of the program, undergraduate students who ttended any of the five 2018 MEDTalks sessions were invited to complete a voluntary and anonymous feedback survey. Thirty-five unique undergraduate students participated in the 2018 program, of whom 29 (83%) responded to the survey