#3 - Inhibition of the Mitochondrial Calcium Uniporter Reduces Oxidative Phosphorylation in SGK1-Knockout VSMC Upon DietInduced Obesity

Obesity is linked to vascular diseases such as atherosclerosis and coronary artery disease which is a major underlying cause of heart attacks. While the mechanism is not fully known, altering mitochondrial respiration which occurs through oxidative phosphorylation (OXPHOS) may influence the development of vascular disease during obesity. Our previous data with diet-induced obese (DIO) mice demonstrated that serum and glucocorticoid-inducible kinase 1 (SGK1), which regulates cell metabolism, was up-regulated in vascular smooth muscle cells (VSMC) from the aorta. Knocking out SGK1 in VSMCs (KOSGK1) was associated with higher OXPHOS and lower vascular disease relative to wildtype VSMCs (WTSGK1) during DIO. The mitochondrial calcium uniporter (MCU) permits calcium uptake into the mitochondrial matrix causing stimulation of OXPHOS thereby contributing to the maintenance of cellular energy homeostasis. We hypothesized that OXPHOS stimulation in KOSGK1 VSMC may be due to enhanced activity of the MCU. To test this hypothesis, an extracellular oxygen consumption (EOC) assay which measures OXPHOS was used to examine the role of MCU-mediated mitochondrial Ca2+ uptake on basal and maximal OXPHOS activity in WTSGK1 and KOSGK1 VSMCs. Thus, WTSGK1 and KOSGK1 VSMCs from DIO mice were treated ± Ru360 (10mM), an MCU inhibitor and ± FCCP (2.5mM) to stimulate maximal OXPHOS. Consistent with previous data, KOSGK1 VSMCs had significantly higher basal and maximal EOC compared to WTSGK1 VSMCs. Remarkably, RU360 significantly decreased both basal and maximal EOC in KOSGK1 VCMCs. Conversely, there was no effect of RU360 on EOC in WTSGK1 VSMCs. These results suggest a disparity in MCU activity in KOSGK1 VSMCs. In conclusion, these findings implicate mitochondrial Ca2+ uptake in the stimulation of OXPHOS in KOSGK1 VSMCs

Niveau de préparation des diplômés à une carrière en médecine interne générale avant et après la reconnaissance de la surspécialité : objectifs atteints et besoins évolutifs dans le programme d’études

Background: A survey of General Internal Medicine (GIM) graduates published in 2006 revealed large training gaps that informed the development of the first national GIM objectives of training in 2010. The first recognized GIM certification examination was written by candidates in 2014. The landscape is again changing with the introduction in 2019 of competency-by-design (CBD) to GIM training. This study aims to examine pre-existing and emerging training gaps with standardization of GIM curricula and identify new training needs to inform CBD curricula.  Methods: GIM graduates from all 16 Canadian programs from 2014 -2019 were emailed a survey modeled after the original study published in 2006. Graduates were asked about their preparedness and importance ratings for various elements of practice. Results: Many of the previously identified gaps (difference between importance and preparedness ratings) have been resolved in specific clinical areas (obstetrical and perioperative medicine) and skills (exercise stress testing) although some still require ongoing work in areas such as substance use disorders. Importantly, gaps still exist in preparedness for some intrinsic roles (e.g. managerial skills). Conclusions:  The development of a national GIM curriculum has helped close some educational gaps but some still exist. Our study provides data needed to meet the evolving needs of our graduates.Contexte : Une enquête auprès des diplômés en médecine interne générale (MIG), publiée en 2006, a révélé d’importantes lacunes dans leur formation, menant à l’élaboration des premiers objectifs nationaux de formation en MIG en 2010. Le premier examen de certification en MIG a été organisé en 2014. Le paysage est à nouveau en train de changer avec l’introduction en 2019 de la compétence par conception (CPC) dans la formation en MIG. Cette étude vise à examiner les lacunes de formation préexistantes et émergentes avec la normalisation de la formation en MIG et à identifier les nouveaux besoins de formation pour éclairer la définition des programmes de formation selon l’approche fondée sur les compétences.  Méthodes : Les diplômés des 16 programmes canadiens en MIG entre 2014 et 2019 ont reçu par courriel un sondage inspiré de l’étude originelle publiée en 2006. Les diplômés ont été interrogés sur leur état de préparation et sur l’importance qu’ils accordaient à divers éléments de la pratique. Résultats : Un grand nombre des lacunes décelées précédemment (différence entre les cotes d’importance et de préparation) ont été comblées dans des domaines cliniques spécifiques (médecine obstétrique et périopératoire) et par rapport à des compétences spécifiques (tests de stress à l’effort); dans certains domaines, comme les troubles liés à l’utilisation de substances psychoactives, les efforts doivent être poursuivis. Il est important de noter que des lacunes subsistent dans la préparation à certains rôles intrinsèques (par exemple, les compétences de gestionnaire). Conclusion : L’élaboration d’un programme national de formation en MIG a permis de combler certaines lacunes en matière de formation, mais des carences subsistent. Notre étude fournit les données nécessaires pour répondre aux besoins évolutifs de nos diplômés

Abrasive Weeding as a Vehicle for Precision Fertilizer Management in Organic Vegetable Production

Abrasive weeding is a nonchemical weed control tactic that uses small, gritty materials propelled with compressed air to destroy weed seedlings. Organic fertilizers have been used successfully as abrasive grits to control weeds, but the goal for this study was to explore the effects of fertilizer grit, application rates, and background soil fertility on weeds, plant available nitrogen (N) uptake, and crop yield. Field trials were conducted in organic ‘Carmen’ sweet red pepper (Capsicum annuum) and organic ‘Gypsy’ broccoli (Brassica oleracea var. italica) and treatments included organic fertilizer grit (8N–0.9P–3.3K vs. 3N–3.1P–3.3K), grit application rates (low vs. high), compost amendments (with and without), and weedy and weed-free controls. Weed biomass was harvested at 84 days and 65 days after transplanting for pepper and broccoli, respectively. Simulated total plant available N (nitrate + ammonium) uptake was measured with ion exchange resin stakes between 7 and 49 days after the first of two grit applications. Produce was harvested at maturity, graded for marketability, and weighed. The higher grit application rate, regardless of fertilizer type, reduced the weed biomass by 75% to 89% for pepper and by 86% to 99% for broccoli. By 5 weeks after the first grit application, simulated plant N uptake was greatest following grit application with the 8% N fertilizer, followed by the 3% N fertilizer, and lowest in the weedy control. The high grit application rate of 8% N fertilizer increased pepper yield by 112% compared with the weedy control, but it was similar to that of the weed-free control. Broccoli was less responsive to abrasive grits, with yield changes ranging from no difference to up to a 36% increase (relative to the weedy control) depending on the application rate and compost amendment. This is the first evidence indicating that the nutrient composition of organic fertilizer abrasive grits can influence in-season soil N dynamics, weed competition, and crop yield. The results suggest that abrasive weeding technology could be leveraged to improve the precision of in-season fertilizer management of organic crops

Potent in vivo anti-malarial activity and representative snapshot pharmacokinetic evaluation of artemisinin-quinoline hybrids

BACKGROUND:Because Plasmodium falciparum displays increase tolerance against the recommended artemisinin combination therapies (ACT), new classes of anti-malarial drugs are urgently required. Previously synthesized artemisinin-aminoquinoline hybrids were evaluated to ascertain whether the potent low nanomolar in vitro anti-plasmodial activity would carry over in vivo against Plasmodium vinckei. A snapshot pharmacokinetic analysis was carried out on one of the hybrids to obtain an indication of the pharmacokinetic properties of this class of anti-malarial drugs. METHODS: In vitro activity of hybrids 2 and 3 were determined against the 3D7 strain of P. falciparum. Plasmodium vinckei-infected mice were treated with hybrids 1 - 3 for four days at a dosage of 0.8mg/kg, 2.5mg/kg, 7.5mg/kg or 15mg/kg intraperitoneally (ip), or orally (per os) with 2.7mg/kg, 8.3mg/kg, 25mg/kg or 50mg/kg. Artesunate was used as reference drug. A snapshot oral and IV pharmacokinetic study was performed on hybrid 2. RESULTS: Hybrids 1 - 3 displayed potent in vivo anti-malarial activity with ED50 of 1.1, 1.4 and <0.8mg/kg by the ip route and 12, 16 and 13mg/kg per os, respectively. Long-term monitoring of parasitaemia showed a complete cure of mice (without recrudescence) at 15mg/kg via ip route and at 50mg/kg by oral route for hybrid 1 and 2, whereas artesunate was only able to provide a complete cure at 30mg/kg ip and 80mg/kg per os. CONCLUSIONS: These compounds provide a new class of desperately needed anti-malarial drug. Despite a short half-life and moderate oral bioavailability, this class of compounds was able to cure malaria in mice at very low dosages. The optimum linker length for anti-malarial activity was found to be a diaminoalkyl chain consisting of two carbon atoms either methylated or unmethylated

Dopaminergic Control of Striatal Cholinergic Interneurons Underlies Cocaine-Induced Psychostimulation

Cocaine drastically elevates dopamine (DA) levels in the striatum, a brain region that is critical to the psychomotor and rewarding properties of the drug. DA signaling regulates intrastriatal circuits connecting medium spiny neurons (MSNs) with afferent fibers and interneurons. While the cocaine-mediated increase in DA signaling on MSNs is well documented, that on cholinergic interneurons (ChIs) has been more difficult to assess. Using combined pharmacological, chemogenetic, and cell-specific ablation approaches, we reveal that the D2R-dependent inhibition of acetylcholine (ACh) signaling is fundamental to cocaine-induced changes in behavior and the striatal genomic response. We show that the D2R-dependent control of striatal ChIs enables the motor, sensitized, and reinforcing properties of cocaine. This study highlights the importance of the DA- and D2R-mediated inhibitory control of ChIs activity in the normal functioning of striatal networks

Semaphorin 3A Contributes to Distal Pulmonary Epithelial Cell Differentiation and Lung Morphogenesis

altered distal lung structure.) littermate controls. mice that survived the immediate perinatal period. Furthermore, Sema3A deletion was linked with enhanced postnatal alveolar septal cell death.These data suggest that Sema3A modulates distal pulmonary epithelial cell development and alveolar septation. Defining how Sema3A influences structural plasticity of the developing lung is a critical first step for determining if this pathway can be exploited to develop innovative strategies for repair after acute or chronic lung injury

A Multi-wavelength Survey of AGN in Massive Clusters: AGN Detection and Cluster AGN Fraction

We aim to study the effect of environment on the presence and fuelling of Active Galactic Nuclei (AGN) in massive galaxy clusters. We explore the use of different AGN detection techniques with the goal of selecting AGN across a broad range of luminosities, AGN/host galaxy flux ratios, and obscuration levels. From a sample of 12 galaxy clusters at redshifts 0.5 < z < 0.9, we identify AGN candidates using optical variability from multi-epoch HST imaging, X-ray point sources in Chandra images, and mid-IR SED power-law fits through the Spitzer IRAC channels. We find 178 optical variables, 74 X-ray point sources, and 64 IR power law sources, resulting in an average of ~25 AGN per cluster. We find no significant difference between the fraction of AGN among galaxies in clusters and the percentage of similarly-detected AGN in field galaxy studies (~2.5%). This result provides evidence that galaxies are still able to fuel accretion onto their supermassive black holes, even in dense environments. We also investigate correlations between the percentage of AGN and cluster physical properties such as mass, X-ray luminosity, size, morphology class and redshift. We find no significant correlations among cluster properties and the percentage of AGN detected.Comment: 68 pages, 22 figures, 15 table

Developmentally arrested structures preceding cerebellar tumors in von Hippel-Lindau disease.

There is increasing evidence that suggests that knockout of tumor-suppressor gene function causes developmental arrest and protraction of cellular differentiation. In the peripheral nervous system of patients with the tumor-suppressor gene disorder, von Hippel-Lindau disease, we have demonstrated developmentally arrested structural elements composed of hemangioblast progenitor cells. Some developmentally arrested structural elements progress to a frank tumor, hemangioblastoma. However, in von Hippel-Lindau disease, hemangioblastomas are frequently observed in the cerebellum, suggesting an origin in the central nervous system. We performed a structural and topographic analysis of cerebellar tissues obtained from von Hippel-Lindau disease patients to identify and characterize developmentally arrested structural elements in the central nervous system. We examined the entire cerebella of five tumor-free von Hippel-Lindau disease patients and of three non-von Hippel-Lindau disease controls. In all, 9 cerebellar developmentally arrested structural elements were detected and topographically mapped in 385 blocks of von Hippel-Lindau disease cerebella. No developmentally arrested structural elements were seen in 214 blocks from control cerebella. Developmentally arrested structural elements are composed of poorly differentiated cells that express hypoxia-inducible factor (HIF)2α, but not HIF1α or brachyury, and preferentially involve the molecular layer of the dorsum cerebelli. For the first time, we identify and characterize developmentally arrested structural elements in the central nervous system of von Hippel-Lindau patients. We provide evidence that developmentally arrested structural elements in the cerebellum are composed of developmentally arrested hemangioblast progenitor cells in the molecular layer of the dorsum cerebelli

The Type Ia Supernova Rate in Redshift 0.5--0.9 Galaxy Clusters

Supernova (SN) rates are potentially powerful diagnostics of metal enrichment and SN physics, particularly in galaxy clusters with their deep, metal-retaining potentials and relatively simple star-formation histories. We have carried out a survey for supernovae (SNe) in galaxy clusters, at a redshift range 0.5<z<0.9, using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. We reimaged a sample of 15 clusters that were previously imaged by ACS, thus obtaining two to three epochs per cluster, in which we discovered five likely cluster SNe, six possible cluster SNe Ia, two hostless SN candidates, and several background and foreground events. Keck spectra of the host galaxies were obtained to establish cluster membership. We conducted detailed efficiency simulations, and measured the stellar luminosities of the clusters using Subaru images. We derive a cluster SN rate of 0.35 SNuB +0.17/-0.12 (statistical) \pm0.13 (classification) \pm0.01 (systematic) [where SNuB = SNe (100 yr 10^10 L_B_sun)^-1] and 0.112 SNuM +0.055/-0.039 (statistical) \pm0.042 (classification) \pm0.005 (systematic) [where SNuM = SNe (100 yr 10^10 M_sun)^-1]. As in previous measurements of cluster SN rates, the uncertainties are dominated by small-number statistics. The SN rate in this redshift bin is consistent with the SN rate in clusters at lower redshifts (to within the uncertainties), and shows that there is, at most, only a slight increase of cluster SN rate with increasing redshift. The low and fairly constant SN Ia rate out to z~1 implies that the bulk of the iron mass in clusters was already in place by z~1. The recently observed doubling of iron abundances in the intracluster medium between z=1 and 0, if real, is likely the result of redistribution of existing iron, rather than new production of iron.Comment: Accepted to ApJ. Full resolution version available at http://kicp.uchicago.edu/~kerens/HSTclusterSNe