31 research outputs found
Impact of MELD allocation policy on survival outcomes after liver transplantation: a single-center study in northeast Brazil
OBJECTIVE: To analyze the impact of model for end-stage liver disease (MELD) allocation policy on survival outcomes after liver transplantation (LT). INTRODUCTION: Considering that an ideal system of grafts allocation should also ensure improved survival after transplantation, changes in allocation policies need to be evaluated in different contexts as an evolutionary process. METHODS: A retrospective cohort study was carried out among patients who underwent LT at the University of Pernambuco. Two groups of patients transplanted before and after the MELD allocation policy implementation were identified and compared using early postoperative mortality and post-LT survival as end-points. RESULTS: Overall, early postoperative mortality did not significantly differ between cohorts (16.43% vs. 8.14%; p = 0.112). Although at 6 and 36-months the difference between pre-vs. post-MELD survival was only marginally significant (p = 0.066 and p = 0.063; respectively), better short, medium and long-term post-LT survival were observed in the post-MELD period. Subgroups analysis showed special benefits to patients categorized as nonhepatocellular carcinoma (non-HCC) and moderate risk, as determined by MELD score (15-20). DISCUSSION: This study ensured a more robust estimate of how the MELD policy affected post-LT survival outcomes in Brazil and was the first to show significantly better survival after this new policy was implemented. Additionally, we explored some potential reasons for our divergent survival outcomes. CONCLUSION: Better survival outcomes were observed in this study after implementation of the MELD criterion, particularly amongst patients categorized as non-HCC and moderate risk by MELD scoring. Governmental involvement in organ transplantation was possibly the main reason for improved survival
A biodiversidade terrestre e dulçaquĂcola dos arquipĂ©lagos da Madeira e das Selvagens
As ilhas atlĂąnticas dos Açores, Madeira, Selvagens, CanĂĄrias e Cabo Verde constituem uma das regiĂ”es da Europa mais ricas em diversidade de fungos, plantas e animais. Desde 2004 que a inventariação detalhada da diversidade destas ilhas tem sido um dos principais objectivos dos projectos ATLĂNTICO e BIONATURA (incluĂdos no projecto EU INTERREG IIIB). Este livro Ă© a mais recente contribuição destes projectos, apresentando uma lista de todos os fungos, flora e fauna terrestre conhecida, incluindo a dulçaquĂcola, para dois arquipĂ©lagos atlĂąnticos (Madeira e Selvagens). A lista abrange o arquipĂ©lago da Madeira, constituĂdo por duas ilhas de maiores dimensĂ”es (Madeira e Porto Santo) e trĂȘs pequenas, cujo conjunto constitui as Desertas (IlhĂ©u ChĂŁo, Deserta Grande e Bugio), e ainda o arquipĂ©lago das Selvagens, formado por duas pequenas ilhas (Selvagem Grande e Selvagem Pequena) e um ilhĂ©u (IlhĂ©u de Fora).ABSTRACT: The Azores, Madeira, Selvagens, Canary Islands and Cape Verde are among the richest regions in Fungi, plant and animal diversity in Europe. The main objectives of the EU INTERREG IIIB projects ATLĂNTICO and BIONATURA have been, since 2004, to carry out a detailed inventory of the terrestrial Fungi, Flora and Fauna of these archipelagos. This book, encompassing a checklist of all the known terrestrial and freshwater Fungi, Flora and Fauna of Madeira and Selvagens archipelagos is the latest contribution towards that goal. The geographic scope of this checklist includes the Madeira archipelago, composed of two large islands (Madeira and Porto Santo) and three small islands, which are globally named Desertas (IlhĂ©u ChĂŁo, Deserta Grande and Bugio), and the archipelago of Selvagens with two small islands (Selvagem Grande and Selvagem Pequena) and one islet (IlhĂ©u de Fora)
Os fósseis de Santa Maria (Açores) : a jazida da Prainha.
PREFĂCIO: O trabalho que agora se apresenta de SĂ©rgio Ăvila e colaboradores Ă© mais um precioso contributo para a divulgação cientĂfica que emerge de trabalho de investigação acadĂ©mica da Universidade dos Açores. Ă um trabalho que procura conciliar um rigor e uma descrição exaustiva e profusamente ilustrada dos elementos factuais paleontolĂłgicos
e geolĂłgicos associados Ă jazida da Prainha, com uma obra apelativa e agradĂĄvel de desfolhar, ler e consultar. Este tipo de produtos acadĂ©micos para a comunidade, de extensĂŁo universitĂĄria como agora se fala, Ă© de extrema importĂąncia para a RegiĂŁo AutĂłnoma dos Açores, em particular, e para Portugal, em geral, por trĂȘs ordens de razĂ”es. Em primeiro lugar porque, contrariamente aos ditados e sabedoria popular, as rochas e outros elementos do patrimĂłnio geolĂłgico, sĂŁo frĂĄgeis e efĂ©meros. Um dos aspectos de maior fragilidade sĂŁo os fĂłsseis, propriamente ditos, o que Ă© mais fĂĄcil de entender. Mais difĂcil Ă© reconhecer que as prĂłprias jazidas fossilĂferas, fĂłsseis e seu enquadramento geolĂłgico, o qual pode incluir filĂ”es, falhas, minerais, seixos rolados, etc., sĂŁo igualmente bastante frĂĄgeis quer a acçÔes de erosĂŁo e alteração naturais quer a acçÔes antrĂłpicas. Quanto Ă s primeiras a Ășnica e melhor atitude Ă© proceder ao seu estudo e registo documental, nomeadamente fotogrĂĄfica, como generosamente se apresenta nesta obra. Quanto Ă s segundas, o modo mais eficaz de as preservar Ă© dar a conhecer Ă s populaçÔes, em geral, e Ă s autarquias e entidades de gestĂŁo do territĂłrio, em particular, no sentido de prevenir o licenciamento de obras ou infra-estruturas que poderĂŁo comprometer irremediavelmente esse PatrimĂłnio Natural. Efectivamente, numa regiĂŁo balnear como a da Praia Formosa, uma eventual pressĂŁo urbanĂstica pode levar Ă destruição destes seus elementos patrimoniais Ășnicos. Ănicos, nĂŁo sĂł no contexto da Ilha de Santa Maria, como no contexto da RegiĂŁo AutĂłnoma dos Açores, ou mesmo do Continente. Em segundo lugar, estĂŁo em curso vĂĄrios esforços no sentido de que o conjunto das nove ilhas açorianas venham a ser integradas na Rede Europeia de Geoparques e, como tal, sejam reconhecidas pela UNESCO como mais um elemento da Global Network of Geoparks. Tal galardĂŁo Ă© consagrado pela excelĂȘncia do seu PatrimĂłnio geolĂłgico e paleontolĂłgico, o qual encontra neste livro um excelente aliado e um repositĂłrio de informação da qual se irĂŁo retirar elementos necessĂĄrios Ă subsequente produção de textos de divulgação em lĂngua estrangeira, fundamentalmente anglo-saxĂłnica. Por outro lado, ficam bem expressos, os argumentos da necessidade desta jazida se converta em mais um dos magnĂficos e bem sucedidos exemplos de geoconservação e valorização ambiental que estĂŁo a registar-se por todo o arquipĂ©lago açoriano. Em terceiro lugar, obras como a que agora se edita ajudam Ă interiorização por parte da população de Santa Maria, e por todos quantos a visitam, da singularidade geolĂłgica desta ilha e do valor cientĂfico e patrimonial que as suas unidades fossilĂferas representam. Elas ilustram de modo particularmente exuberante as alteraçÔes climĂĄticas que o nosso Planeta tem vindo a sofrer, actualmente acompanhadas com maior acuidade pela sociedade e os media. Estes afloramentos particularmente ricos em conteĂșdo fĂłssil, intercalados ou embutidos em sequĂȘncias de rochas vulcĂąnicas e sedimentares, sĂŁo os Ășnicos testemunhos que restam das comunidades biĂłticas que povoaram as ĂĄguas superficiais e as regiĂ”es costeiras insulares do AtlĂąntico Norte, hĂĄ milhares de anos (no caso da Prainha ou Lagoinhas) ou mesmos hĂĄ milhĂ”es de anos, como as jazidas do Monumento Natural Regional da Pedreira do Campo, Pedreira da CrĂ©, âPedra que Picaâ ou Ponta da Malbusca, para citar sĂł algumas. Todas elas sĂŁo singulares excepçÔes que complementam os registos sedimentares das bacias oceĂąnicas envolventes, os quais tĂȘm sido, e continuarĂŁo a ser, alvo de investigação paleoceanogrĂĄfica do Global Change. No entanto, estas jazidas, sĂŁo os Ășnicos testemunhos das comunidades costeiras pretĂ©ritas, com as quais Ă© possĂvel estabelecer comparaçÔes e mapas de distribuição biogeogrĂĄfica, um dos temas fortes presentes nesta obra. (MĂĄrio CachĂŁo)Universidade dos Açores; Departamento de Biologia da UAĂ; CIBIO-Açores; IMAR; CĂąmara Municipal de Vila do Porto; Clube Naval de Santa Maria; GEOBIOTEC; Viagens de Turismo MELO; Hotel Praia de Lobos; Governo dos Açores; Secretaria Regional da CiĂȘncia, Tecnologia e Equipamentos
Impact of MELD allocation policy on survival outcomes after liver transplantation: a single-center study in northeast Brazil
OBJECTIVE: To analyze the impact of model for endâstage liver disease (MELD) allocation policy on survival outcomes after liver transplantation (LT). INTRODUCTION: Considering that an ideal system of grafts allocation should also ensure improved survival after transplantation, changes in allocation policies need to be evaluated in different contexts as an evolutionary process. METHODS: A retrospective cohort study was carried out among patients who underwent LT at the University of Pernambuco. Two groups of patients transplanted before and after the MELD allocation policy implementation were identified and compared using early postoperative mortality and postâLT survival as endâpoints. RESULTS: Overall, early postoperative mortality did not significantly differ between cohorts (16.43% vs. 8.14%; pâ=â0.112). Although at 6 and 36âmonths the difference between preâ vs. postâMELD survival was only marginally significant (pâ=â0.066 and pâ=â0.063; respectively), better short, medium and longâterm postâLT survival were observed in the postâMELD period. Subgroups analysis showed special benefits to patients categorized as nonâhepatocellular carcinoma (nonâHCC) and moderate risk, as determined by MELD score (15â20). DISCUSSION: This study ensured a more robust estimate of how the MELD policy affected postâLT survival outcomes in Brazil and was the first to show significantly better survival after this new policy was implemented. Additionally, we explored some potential reasons for our divergent survival outcomes. CONCLUSION: Better survival outcomes were observed in this study after implementation of the MELD criterion, particularly amongst patients categorized as nonâHCC and moderate risk by MELD scoring. Governmental involvement in organ transplantation was possibly the main reason for improved survival
Recent geospatial dynamics of Terceira (Azores, Portugal) and the theoretical implications for the biogeography of active volcanic islands
Ongoing work shows that species richness patterns on volcanic oceanic islands are shaped by surface area changes driven by longer time scale (>1 ka) geological processes and natural sea level fluctuations. A key question is: what are the rates and magnitudes of the forces driving spatial changes on volcanic oceanic islands which in turn affect evolutionary and biogeographic processes? We quantified the rates of surface-area changes of a whole island resulting from both volcanogenic flows and sea level change over the last glacial-interglacial (GI) cycle (120 ka) for the volcanically active island of Terceira, (Azores, Macaronesia, Portugal). Volcanogenic activity led to incidental but long-lasting surface area expansions by the formation of a new volcanic cone and lava-deltas, whereas sea level changes led to both contractions and expansions of area. The total surface area of Terceira decreased by as much as 24% per time step due to changing sea levels and increased by 37% per time step due to volcanism per time step of 10 ka. However, while sea levels nearly continuously changed the total surface area, volcanic activity only impacted total surface area during two time steps over the past 120 ka. The surface area of the coastal and lowland region (here defined as area <300 m) was affected by sea level change (average change of 11% / 10 ka for 120â0 ka) and intra-volcanic change (average change of 17% / 10 ka for 120â0 ka). We discuss the biogeographic implications of the quantified dynamics, and we argue that surface area change is mainly driven by volcanic processes in the early stages of the islandâs life cycle, while during the later stages, area change becomes increasingly affected by sea level dynamics. Both environmental processes may therefore affect biota differently during the life cycle of volcanic oceanic islands.S.J.N. received funding from the Portuguese National Funds, through Fundação para a CiĂȘncia e a Tecnologia (FCT), within the project UID/BIA/00329/2013 and the Research Fellowship PD/BD/114380/2016. S.P.A. acknowledges his research contract (IF/00465/2015) funded by the Portuguese Science Foundation (FCT). C.S.M. is benefiting from a PhD grant M3.1.a/F/100/2015 from FRCT/Açores 2020 by Fundo Regional para a CiĂȘncia e Tecnologia (FRCT). Financial support to R.A. was received from the Laboratory of Excellence âTULIPâ (PIA-10-LABX-41). This work was supported by FEDER funds through the Operational Programme for Competitiveness Factors â COMPETE and by National Funds through FCT under the UID/BIA/50027/2013, POCI-01-0145-FEDER-006821 and under DRCT-M1.1.a/005/Funcionamento-C-/2016 (CIBIO-A) project from FRCT. This work was also supported by FEDER funds (in 85%) and by funds of the Regional Government of the Azores (15%) through Programa Operacional Açores 2020, in the scope of the project âAZORESBIOPORTAL â PORBIOTAâ: ACORESâ01â0145-FEDER-000072.info:eu-repo/semantics/publishedVersio
Secreted Human Amyloid Precursor Protein Binds Semaphorin 3a and Prevents Semaphorin-Induced Growth Cone Collapse
The amyloid precursor protein (APP) is well known for giving rise to the amyloid-ÎČ peptide and for its role in Alzheimer's disease. Much less is known, however, on the physiological roles of APP in the development and plasticity of the central nervous system. We have used phage display of a peptide library to identify high-affinity ligands of purified recombinant human sAPPα695 (the soluble, secreted ectodomain from the main neuronal APP isoform). Two peptides thus selected exhibited significant homologies with the conserved extracellular domain of several members of the semaphorin (Sema) family of axon guidance proteins. We show that sAPPα695 binds both purified recombinant Sema3A and Sema3A secreted by transfected HEK293 cells. Interestingly, sAPPα695 inhibited the collapse of embryonic chicken (Gallus gallus domesticus) dorsal root ganglia growth cones promoted by Sema3A (Kdâ€8·10â9 M). Two Sema3A-derived peptides homologous to the peptides isolated by phage display blocked sAPPα binding and its inhibitory action on Sema3A function. These two peptides are comprised within a domain previously shown to be involved in binding of Sema3A to its cellular receptor, suggesting a competitive mechanism by which sAPPα modulates the biological action of semaphorins
Genetic Diversity and Population History of a Critically Endangered Primate, the Northern Muriqui (Brachyteles hypoxanthus)
Social, ecological, and historical processes affect the genetic structure of primate populations, and therefore have key implications for the conservation of endangered species. The northern muriqui (Brachyteles hypoxanthus) is a critically endangered New World monkey and a flagship species for the conservation of the Atlantic Forest hotspot. Yet, like other neotropical primates, little is known about its population history and the genetic structure of remnant populations. We analyzed the mitochondrial DNA control region of 152 northern muriquis, or 17.6% of the 864 northern muriquis from 8 of the 12 known extant populations and found no evidence of phylogeographic partitions or past population shrinkage/expansion. Bayesian and classic analyses show that this finding may be attributed to the joint contribution of female-biased dispersal, demographic stability, and a relatively large historic population size. Past population stability is consistent with a central Atlantic Forest Pleistocene refuge. In addition, the best scenario supported by an Approximate Bayesian Computation analysis, significant fixation indices (ΊSTâ=â0.49, ΊCTâ=â0.24), and population-specific haplotypes, coupled with the extirpation of intermediate populations, are indicative of a recent geographic structuring of genetic diversity during the Holocene. Genetic diversity is higher in populations living in larger areas (>2,000 hectares), but it is remarkably low in the species overall (Ξâ=â0.018). Three populations occurring in protected reserves and one fragmented population inhabiting private lands harbor 22 out of 23 haplotypes, most of which are population-exclusive, and therefore represent patchy repositories of the species' genetic diversity. We suggest that these populations be treated as discrete units for conservation management purposes