ESAV - DZERV - Documentos de congressos (comunicações, posters, actas)
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- Age influence in BBN induced urothelial lesions in ICR male micePublication . Vasconcelos-Nóbrega, C.; Mega, C.; Arantes, R.; Talhada, D.; Teixeira-Guedes, C.; Faustino-Rocha, A.; Vala, Helena; Oliveira, P. A.
- A alteração climática na “fixação” do amónio em solos cultivados com arroz (Oryza sativa) por alagamentoPublication . Figueiredo, N.; Carranca, C.; Coutinho, J.; Trindade, H.; Pereira, J.; Prazeres, A.; Marques, P.O arroz, é essencialmente produzido como monocultura, em canteiros alagados, nas regiões do centro e sul do País (Vales do Mondego, Tejo e Sado). O ião NH4 + é a forma de N mineral mais abundante e preferencialmente absorvida pelo arroz, em condições de alagamento. O alagamento potencia a mineralização, por acção dos microrganismos aeróbios facultativos, aumentando a sua concentração na solução do solo. No solo, este catião pode ser adsorvido nos colóides ou "fixado" nos minerais argilosos do tipo 2:1, tornando-se temporariamente indisponível para a cultura. A taxa de "fixação" e posterior libertação para a solução depende da textura do solo, do teor e mineralogia da argila, pH, potencial redox, temperatura e presença de outros catiões. Não se conhecem os efeitos do aumento simultâneo da concentração de CO2 na atmosfera e da temperatura na "fixação" do NH4 + , sabendo-se que, isoladamente, o aumento da temperatura potencia a "fixação". Neste estudo, avaliou-se o teor de NH4 + em dois solos (areno-franco e argilo-limoso) alagados e cultivados com arroz, em 2012, como resposta à fertilização mineral e ao alagamento. Compararam-se esses teores com os medidos no solo argilo-limoso, em condições controladas de aumento da [CO2] e temperatura. O teor de NH4 + "fixado" em ambos os solos (ar livre) foi superior ao da concentração de NH4 + disponível no respectivo solo. A concentração de NH4 + "fixada" no solo argilo-limoso manteve-se superior à do solo arenofranco, variando com os tratamentos (ar livre > CO2+temperatura = temperatura), com as datas de amostragem e com a fertilização azotada.
- Ammonia and greenhouse gas emissions from slatted and solid floors in dairy cattle houses: A scale model studyPublication . Pereira, J.; Fangueiro, D.; Misselbrook, T.H.; Chadwick, D.R.; Coutinho, J.; Trindade, H.Dairy cattle are usually housed in naturally ventilated houses where removal of excreta is periodically performed. The aim of this controlled study was to compare the effect of two floor designs and three air temperatures (5, 15 and 25 C) on NH3, N2O, CH4 and CO2 emissions arising from cattle excreta deposition to the floor. Two scale models were built to simulate a level solid floor without urine drainage, and a slatted concrete floor. Following application of a mixture of urine and faeces, these two floor type models were subjected to a constant airflow rate (12.5 exchanges h 1 ) and gaseous emissions were measured over a 72-h period. Emissions of NH3, N2O, CO2 and CH4 increased significantly with air temperature with both floor type models and emissions of NH3, N2O and CO2 were significantly greater from the solid floor relative to the slatted floor at all temperatures considered. The cumulative NH3 (27e66% of total N applied) and CO2 (<19% of total C applied) emissions were greater from the solid floor than from the slatted floor (by 36% and 44%, respectively). The cumulative N2O (<0.1% of total N applied) and CH4 (<0.4% of total C applied) emissions were relatively low and CH4 values did not differ significantly between treatments. Cumulative greenhouse gas emissions (as CO2-equivalents) increased significantly with temperature but did not differ between the floor types.
- Ammonia emissions from dairy cattle buildings and outdoor concrete yards under the Mediterranean conditions of NW PortugalPublication . Pereira, J.; Misselbrook, T.H.; Chadwick, D.R.; Coutinho, J.; Trindade, H.Around 75% of European ammonia emissions comes from livestock production and emissions occur at all stages of manure management. Ammonia emissions have never been measured in commercial dairy cattle houses in Portugal. The objective of our study was to evaluate NH3 emissions for the main types of dairy cattle buildings naturally ventilated and outdoor concrete yards in NW Portugal.
- Ammonia emissions from naturally ventilated dairy cattle buildings and outdoor concrete yards in PortugalPublication . Pereira, J.; Misselbrook, T.H.; Chadwick, D.R.; Coutinho, J.; Trindade, H.There is a lack of information on ammonia (NH3) emissions from cattle housing systems in Mediterranean countries, with most published data deriving from NW Europe. An investigation was carried out in NW Portugal to quantify NH3 emissions for the main types of dairy cattle buildings in Portugal, i.e. naturally ventilated buildings and outdoor concrete yards, and to derive robust emission factors (EFs) for these conditions and compare with EFs used elsewhere in Europe. Measurements were made throughout a 12-month period using the passive flux sampling method in the livestock buildings and the equilibrium concentration technique in outdoor yards. The mean NH3 emission factor for the whole housing system (buildings þ outdoor yards) was 43.7 g NH3eN LU 1 day 1 and for outdoor concrete yards used by dairy cattle was 26.6 g NH3eN LU 1 day 1 . Expressing NH3 emission in terms of the quantity of liquid milk produced gave similar values across the three dairy farms studied (with a mean of 2.3 kg N ton-milk 1 produced) and may have advantages when comparing different farming systems. In dairy houses with outdoor yards, NH3 emissions from the yard area contributed to 69e92% of total emissions from this housing system. Emissions were particularly important during spring and summer seasons from outdoor yards with NH3 emitted in this period accounting for about 72% of annual emissions from outdoor yards. Mean NH3 emission factors derived for this freestall housing system and outdoor concrete yards used by dairy cattle in Portugal were higher than those measured in northern Europe. In addition, values of animal N excretion estimated in this study were greater than official National standard values. If these emissions are typical for Portuguese dairy systems, then the current National inventory underestimates emissions from this source in NW of Portugal, because of the use of lower standard values of N excretion by dairy cattle.
- An IT Software System for Using Experience in Veterinary Pathological AnatomyPublication . Vala, Helena; Tomé, P.Background: Veterinary anatomical pathology is a medical specialty similar to human anatomical pathology, which aims to obtain a final pathological diagnosis, applying criteria based mostly in the knowledge of the gross and histological lesions. The main difficulties in veterinary pathological diagnosis are related to the various animal species a pathologist has to deal with, the use of exhaustive classifications of different types, the costs, the subjectivity and the urgency in issuing the report. So, the urgent need to compile all available information to obtain a diagnosis, in a short period of time, is the constant challenge placed to the professional experts in the area concerned. Methods: Authors propose a framework and a software system (which uses experience) that can be useful for diagnosis purposes. The framework is based on the analysis of the bibliography of the domain. The software system applies Case Based Reasoning for retrieving past solved cases and suggest the solution to the veterinarian professional. Results: The software system was already tested in a set of 921 and revealed that 69.6% of cases could be adapted, indicating a high level of similarity. Conclusions: Both proposals can be useful tools in helping to make a better diagnosis.
- Apontamento histórico. Fundamentos e evolução da imunologiaPublication . Almeida, D.; Moreira, R.; Capela, I.; Vala, HelenaINTRODUÇÃO: No século XII, investigadores chineses observaram que os indivíduos que se recuperavam da varíola eram resistentes a ataques posteriores desta doença. Perante esta observação, infectaram crianças deliberadamente com a varíola, esfregando crostas de indivíduos infectados em pequenos cortes na pele das crianças, tendo verificado que as que sobreviviam ficavam protegidas contra a varíola para o resto da sua vida. Com o aumento da experiência no uso desta técnica, os chineses perceberam que os casos eram minimizados utilizando-se crostas de casos leves de varíola (Tizard, 2008). No século XVI, Hieronymus Fracastorius (Verona), no seu livro De contagionibus et contagiosis morbis et eorum curatione (1546), foi o primeiro a postular a ideia de que o contagium fosse devido a agentes vivos, criando assim, a doutrina do contagium vivum (Silva, 2001). Contudo foi, em 1754, que surgiu a ideia de que a inoculação poderia ajudar a controlar os surtos de peste bovina que tinham ocorrência desde o século IX e inevitavelmente matavam um grande número de bovinos. Esse processo consistia na embebição de um pedaço de corda com secreção nasal de um animal infectado e na sua inserção no interior de uma incisão na pata do animal que se pretendia proteger. A doença resultante era normalmente mais suave que a infecção natural e o animal inoculado tornava-se resistente à doença. O processo mostrou-se muito popular e inoculadores capacitados viajavam pela Europa inoculando bovinos e marcando-os para mostrar que estavam protegidos contra a peste bovina (Tizard, 2008). Em 1798, Edward Jenner, um médico inglês, demonstrou que o material de lesões de varíola bovina poderia ser substituído pelo da varíola humana na variolação. Como a varíola bovina não causava doença grave no homem, o uso desse procedimento reduziu os riscos decorrentes da “variolação” em níveis insignificantes. Estava descoberto um princípio da vacinação: a exposição a uma estirpe de um organismo não causador de doença numa determinada espécie pode conceder protecção contra a estirpe causadora de doença nessa espécie animal. A eficácia dessa técnica, denominada vacinação (o nome advém de vaccinia, o agente infeccioso da varíola bovina) foi tal que levou a Organização Mundial de Saúde a anunciar, em 1980 que a varíola era a primeira doença infecciosa a ser erradicada em todo mundo através da implementação de um programa de vacinação (Tizard, 2008; DGS, 2004). Em 1879, em França, Louis Pasteur, investigou a cólera aviária, doença causada pela bactéria hoje conhecida como Pasteurella multocida e descobre outro princípio da vacinação: a exposição de uma espécie animal a uma estirpe envelhecida/enfraquecida (estirpe não virulenta) pode provocar uma resposta imune que irá proteger o animal contra a infecção subsequente por uma estirpe produtora de doença (virulenta) do mesmo ou de um microrganismo relacionado (Silva, 2001; Tizard, 2008). Mais tarde é desenvolvida a teoria de que os fagócitos, do grego “devorador de células", eram a primeira e mais importante linha de defesa contra a infecção (Pelczar et al., 1996) e a protecção induzida pelos processos de vacinação (Silva, 2001). Seguiram-se grandes nomes no século XX que contribuíram para o desenvolvimento da ciência que é hoje a imunologia.
- Apoptosis as a prognostic marker in prediction of renal injury, after acute bleeding and volume replacement with HES 130/0.4 or Ringer solution, in a pig modelPublication . Cruz, R.; Vala, Helena; Machado, A.; Venâncio, C.; Mesquita, J.; Silva, A.; Ortiz, A. L.; Ferreira, D.Objectives: The aim of this study is to identify and quantify apoptosis in renal tissue, using a biochemical marker (TUNEL) in a pig haemorrhagic model, after intravascular volume replacement with Ringer's lactate RL) or Hydroxyethylstarch (HES) 130/0.4) solutions. Methods: 18 Large White pigs underwent total intravenous anaesthesia (TIVA) with propofol and remifentanil. 25 ml/kg of arterial blood were removed from the femoral artery. Volume was replaced, RL, in group1 (n=6) and HES 130/0.4, in group2 (n=6), 20 min after bleeding. The control group did not face bleeding and volume reposition. One hour after volume replacement, pigs were euthanized with intravenous KCl, and renal tissue samples were taken for several studies, including immunohistochemically with in situ TUNEL method for apoptosis detection. ANOVA was used to compare data between groups. Results: In all groups apoptosis was, as expected, mainly detected in epithelial tubular cells of the proximal and distal convoluted tubules, in the loop of Henle and in the epithelium of collecting tubules, however the number of apoptotic cells per mm2 was lower in group 1 (35.68 apoptotic cells/mm2), when compared with group 2 (67.94 apoptotic cells/mm2) and the control group (146.34 apoptotic cells/mm2). The level of apoptosis was significantly higher in Ringer Lactate group, comparing with controls group, for the epithelial tubular cells (P<0.05). Conclusion: The median apoptotic levels were significantly lower in pigs, subjected to fluid replacement with RL, when compared with HES 130/0.4. Ringer lactate might promote better renal perfusion in the presence of severe hypovolaemia following acute haemorrhage.
- Avaliação quantitativa do parasitismo intestinal em aves de produção.Publication . Monteiro, L.; Marques, V.; Vala, Helena
- Biochemical and histological effects of sitagliptin on Zucker Diabetic Fatty rat pancreasPublication . Mega, C.; Vala, Helena; Teixeira de Lemos, E.; Fernandes, R.; Oliveira, J.; Ferreira, L.; Teixeira, F.; Reis, F.Background: Inhibition of dipeptidyl peptidase-4 (DPP-4) activity by sitagliptin has been shown to improve glycemic control in patients with type 2 diabetes Mellitus (T2DM) by prolonging the actions of incretin hormones, but the really impact of low-dose sitagliptin treatment on pancreas lesions is almost unknown. This study aimed to evaluate the effects of sitagliptin on biochemical and histological (pancreas) parameters of Zucker Diabetic Fatty (ZDF, fa/fa) rats, an animal model of T2DM. Methods: Diabetic (fa/fa) ZDF male rats were treated with vehicle or sitagliptin (10 mg/kg BW/day) during 6 weeks (n=8 each). The following parameters were assessed: serum glycaemia, HbA1c, insulin and lipid profile; serum and pancreas oxidative stress (MDA) and endocrine and exocrine pancreas histology, estimating and rating inflammatory infiltrate, fibrosis, vacuolization and congestion in a semiquantitative score ranging from 0 (minimal) to 3 (severe and extensive damage). Results: Sitagliptin in diabetic ZDF rats promoted beneficial effects on dysglycaemia, dyslipidaemia, inflammatory profile and pancreatic oxidative stress. Endocrine and exocrine pancreas presented a reduction/amelioration of fibrosis severity, inflammatory infiltrate, intra-islet vacuolation, and congestion vs the vehicle-treated diabetic rats. Conclusions: The favourable biochemical profile promoted by sitagliptin in the diabetic rats, together with a protection against endocrine and exocrine pancreas lesions, might represent a further advantage of low doses of sitagliptin in the management of T2DM.