Acção da progesterona em mecanismos de fosforização proteica no sistema nervoso central

Doutoramento em BiologiaO presente trabalho propõe-se esclarecer o papel que a progesterona e os seus metabolitos exercem no sistema nervoso central. Nos últimos anos, com a descoberta da síntese local de esteróides no cérebro, a progesterona, assim como outras hormonas sexuais, ganharam uma relevância crescente em fenómenos tais como plasticidade neuronal e neuroprotecção. Ainda que já se comece a entender o papel de muitas hormonas no cérebro, tal como o estrogénio, o papel da progesterona continua menos conhecido. Deste modo, o nosso trabalho centrou-se na elucidação dos efeitos da progesterona em fenómenos de sobrevivência celular, plasticidade neuronal/sináptica. Graças à colaboração com um grupo pioneiro em estudos sobre hormonas sexuais neuroactivas, o presente trabalho fornece uma importante contribuição ao entendimento do papel desta hormona no sistema nervoso central. Este trabalho fornece novos dados, relativamente ao papel da progesterona e dos seus metabolitos reduzidos na regulação de vias de sinalização associadas com sobrevivência celular, tal como Akt/PI3K e ERK. Também é analisado o efeito do tratamento hormonal na expressão e estado de fosforilação da proteína Tau, sendo ainda motivo de estudo cinases e fosfatases envolvidas nestes mecanismos.The present work has as its main aim, to unveil the role of progesterone and its reduced metabolites in the central nervous system. In the last years, with the discovery of local synthesis of steroids in the brain, progesterone, as well as other sexual hormones, acquired a new importance in brain phenomena like neuronal plasticity and neuroprotection. Although the role of many hormones in the brain, like the estrogen, is starting to be well known, the role of progesterone was less studied. Therefore, our work aim was to study the progesterone effects in the brain regarding cellular survival and neuronal/synaptic plasticity. Thanks to the collaboration with a group pioneer in neuroactive sexual hormones studies, the present works provides an important contribution on the role of this hormone in the central nervous system. This work offers new data regarding the role of progesterone and its reduced metabolites in the regulation of signaling pathways associated with cellular survival, like the Akt/PI3K and ERK. It is also studied the effect of hormonal treatment in the expression and phosphorylation state of Tau protein, as well as the kinases and phosphatases involved in these mechanisms.FCT - SFRH/19304/2004/R30

Decrease in PTEN and increase in Akt expression and neuron size in aged rat spinal cord

PTEN is a tumor suppressor gene known to play an important role in the regulation of cell size. In this study we compared PTEN expression in the spinal cord of young (5 months old) vs. aged (32 months old) female rats and correlated them with alterations in neuron size and morphology in the same animals. Total and phosphorylated PTEN (pPTEN) as well as its downstream target phosphorylated Akt (pAkt) were assessed by Western blotting. Spinal cord neurons were morphometrically characterized. Total PTEN, pPTEN and total Akt expression were significantly higher in young rats than in aged animals. Expression of pAkt was stronger in aged animals. A significant increase in neuronal size was observed in large motoneurons of aged as compared with young rats. Our data show that in the spinal cord of rats, neuronal PTEN expression diminishes with advanced age while neuronal size increases. These results suggest that in the spinal cord, an age-related reduction in PTEN and increase of pAkt expression may be involved in the progressive enlargement of neurons.INIBIOLPFacultad de Ciencias Veterinaria

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

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

Decrease in PTEN and increase in Akt expression and neuron size in aged rat spinal cord

PTEN is a tumor suppressor gene known to play an important role in the regulation of cell size. In this study we compared PTEN expression in the spinal cord of young (5. months old) vs. aged (32. months old) female rats and correlated them with alterations in neuron size and morphology in the same animals. Total and phosphorylated PTEN (pPTEN) as well as its downstream target phosphorylated Akt (pAkt) were assessed by Western blotting. Spinal cord neurons were morphometrically characterized. Total PTEN, pPTEN and total Akt expression were significantly higher in young rats than in aged animals. Expression of pAkt was stronger in aged animals. A significant increase in neuronal size was observed in large motoneurons of aged as compared with young rats. Our data show that in the spinal cord of rats, neuronal PTEN expression diminishes with advanced age while neuronal size increases. These results suggest that in the spinal cord, an age-related reduction in PTEN and increase of pAkt expression may be involved in the progressive enlargement of neurons. © 2010 Elsevier Inc.Peer Reviewe

NEOTROPICAL ALIEN MAMMALS: a data set of occurrence and abundance of alien mammals in the Neotropics

Biological invasion is one of the main threats to native biodiversity. For a species to become invasive, it must be voluntarily or involuntarily introduced by humans into a nonnative habitat. Mammals were among first taxa to be introduced worldwide for game, meat, and labor, yet the number of species introduced in the Neotropics remains unknown. In this data set, we make available occurrence and abundance data on mammal species that (1) transposed a geographical barrier and (2) were voluntarily or involuntarily introduced by humans into the Neotropics. Our data set is composed of 73,738 historical and current georeferenced records on alien mammal species of which around 96% correspond to occurrence data on 77 species belonging to eight orders and 26 families. Data cover 26 continental countries in the Neotropics, ranging from Mexico and its frontier regions (southern Florida and coastal-central Florida in the southeast United States) to Argentina, Paraguay, Chile, and Uruguay, and the 13 countries of Caribbean islands. Our data set also includes neotropical species (e.g., Callithrix sp., Myocastor coypus, Nasua nasua) considered alien in particular areas of Neotropics. The most numerous species in terms of records are from Bos sp. (n = 37,782), Sus scrofa (n = 6,730), and Canis familiaris (n = 10,084); 17 species were represented by only one record (e.g., Syncerus caffer, Cervus timorensis, Cervus unicolor, Canis latrans). Primates have the highest number of species in the data set (n = 20 species), partly because of uncertainties regarding taxonomic identification of the genera Callithrix, which includes the species Callithrix aurita, Callithrix flaviceps, Callithrix geoffroyi, Callithrix jacchus, Callithrix kuhlii, Callithrix penicillata, and their hybrids. This unique data set will be a valuable source of information on invasion risk assessments, biodiversity redistribution and conservation-related research. There are no copyright restrictions. Please cite this data paper when using the data in publications. We also request that researchers and teachers inform us on how they are using the data