Effects of leucine supplementation and resistance exercise on dexamethasone-induced muscle atrophy and insulin resistance in rats

Objective: We aimed to evaluate the effects of resistance exercise (RE) and leucine (LEU) supplementation on dexamethasone (DEXA)-induced muscle atrophy and insulin resistance.Methods: Male Wistar rats were randomly divided into DEXA(DEX), DEXA + RE (DEX-RE), DEXA + LEU (DEX-LEU), and DEXA + RE + LEU (DEX-RE-LEU) groups. Each group received DEXA 5 mg . kg(-1) . d(-1) for 7 d from drinking water and were pair-fed to the DEX group; LEU-supplemented groups received 0.135 g . kg(-1) . d(-1) through gavage for 7 d; the RE protocol was based on three sessions of squat-type exercise composed by three sets of 10 repetitions at 70% of maximal voluntary strength capacity.Results: the plantaris mass was significantly greater in both trained groups compared with the non-trained groups. Muscle cross-sectional area and fiber areas did not differ between groups. Both trained groups displayed significant increases in the number of intermediated fibers (IIa/IIx), a decreased number of fast-twitch fibers (IIb), an increased ratio of the proteins phospho(Ser2448)/ total mammalian target of rapamycin and phospho(Thr389)/total 70-kDa ribosomal protein S6 kinase. and a decreased ratio of phospho(Ser253)/total Forkhead box protein-3a. Plasma glucose was significantly increased in the DEX-LEU group compared with the DEX group and RE significantly decreased hyperglycemia. the DEX-LEU group displayed decreased glucose transporter-4 translocation compared with the DEX group and RE restored this response. LEU supplementation worsened insulin sensitivity and did not attenuate muscle wasting in rats treated with DEXA. Conversely, RE modulated glucose homeostasis and fiber type transition in the plantaris muscle.Conclusion: Resistance exercise but not LEU supplementation promoted fiber type transition and improved glucose homeostasis in DEXA-treated rats. (C) 2012 Elsevier Inc. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Univ São Paulo, Lab Appl Nutr & Metab, Sch Phys Educ & Sports, São Paulo, BrazilUniv São Paulo, Inst Biomed Sci, São Paulo, BrazilUniv São Paulo, Lab Mol & Cellular Physiol Exercise, Sch Phys Educ & Sports, São Paulo, BrazilUniv São Paulo, Sch Med, Lab Expt Hypertens, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biosci, São Paulo, BrazilClermont Univ, UFR Med, UMR Nutr Humaine 1019, Clermont Ferrand, FranceINRA, UMR Unite Nutr Humaine 1019, F-63122 St Genes Champanelle, FranceUniversidade Federal de São Paulo, Dept Biosci, São Paulo, BrazilFAPESP: 08/51090-1FAPESP: 10/07062-3FAPESP: 10/10852-6FAPESP: 11/04690-6Web of Scienc

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Chronic resistance training decreases MuRF-1 and Atrogin-1 gene expression but does not modify Akt, GSK-3 beta and p70S6K levels in rats

Long-term adaptation to resistance training is probably due to the cumulative molecular effects of each exercise session. Therefore, we studied in female Wistar rats the molecular effects of a chronic resistance training regimen (3 months) leading to skeletal muscle hypertrophy in the plantaris muscle. Our results demonstrated that muscle proteolytic genes MuRF-1 and Atrogin-1 were significantly decreased in the exercised group measured 24 h after the last resistance exercise session (41.64 and 61.19%, respectively; P < 0.05). Nonetheless, when measured at the same time point, 4EBP-1, GSK-3 beta and eIF2B epsilon mRNA levels and Akt, GSK-3 beta and p70S6K protein levels (regulators of translation initiation) were not modified. Such data suggests that if gene transcription constitutes a control point in the protein synthesis pathway this regulation probably occurs in early adaptation periods or during extreme situations leading to skeletal muscle remodeling. However, proteolytic gene expression is modified even after a prolonged resistance training regimen leading to moderate skeletal muscle hypertrophy.Brazilian Funding Agency (FAPESP-Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)[08/51090-1]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP