Percorrer por autor "Silva, Joao"
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- Comparing the continuous geboes score with the Robarts Histopathology Index: definitions of histological remission and response and their relation to faecal calprotectin levelsPublication . Magro, Fernando; Lopes, Joanne; Borralho, Paula; Lopes, Susana; Coelho, Rosa; Cotter, Jose; de Castro, Francisca Dias; Sousa, Helena Tavares; Salgado, Marta; Andrade, Patricia; Vieira, Ana Isabel; Figueiredo, Pedro; Caldeira, Paulo; Sousa, A.; Duarte, Maria A.; Avila, Filipa; Silva, Joao; Moleiro, Joana; Mendes, Sofia; Giestas, Silvia; Ministro, Paula; Sousa, Paula; Goncalves, Raquel; Goncalves, Bruno; Oliveira, Ana; Chagas, Cristina; Cravo, Marilia; Dias, Claudia Camila; Afonso, Joana; Portela, Francisco; Santiago, Mafalda; Geboes, Karel; Carneiro, FatimaBackground and Aims: The histological status of ulcerative colitis [UC] patients in clinical and endoscopic remission has gained space as an important prognostic marker and a key component of disease monitoring. Our main aims were to compare two histological indexes-the continuous Geboes score [GS] and the Robarts Histopathology index [RHI]-regarding their definitions of histological remission and response, and the ability of faecal calprotectin [FC] levels to discriminate between these statuses. Methods: This was an analysis of three prospective cohorts including 422 patients previously enrolled in other studies. Results: The two continuous scores [GS and RHI] were shown to be significantly correlated [correlation coefficient of 0.806, p < 0.001] and particularly close regarding their definition of histological response: 95% and 88% of all patients classified as having/not having [respectively] histological response according to RHI also did so according to GS. Moreover, median FC levels in patients with histological response were lower than those in patients without histological response [GS: 73.00 vs 525.00, p < 0.001; RHI: 73.50 vs 510.00, p < 0.001]; a similar trend was observed when FC levels of patients in histological remission were compared to those of patients with histological activity [GS: 76.00 vs 228.00, p < 0.001; RHI: 73.50 vs 467.00, p < 0.001]. FC levels allowed us to exclude the absence of histological remission [according to RHI] and absence of histological response [according to RHI and GS], with negative predictive values varying from 82% to 96%. However, optimization of the FC cut-off to exclude the absence of histological remission, as for the continuous GS, falls within values that resemble those of the healthy population. Conclusion: The continuous GS and RHI histological scores are strongly correlated in their definitions of histological response. An absence of histological remission could only be excluded at physiological levels of FC.
- Comparison of different histological indexes in the assessment of UC activity and their accuracy regarding endoscopic outcomes and faecal calprotectin levelsPublication . Magro, Fernando; Lopes, Joanne; Borralho, Paula; Lopes, Susana; Coelho, Rosa; Cotter, Jose; de Castro, Francisca Dias; Sousa, Helena Tavares; Salgado, Marta; Andrade, Patricia; Vieira, Ana Isabel; Figueiredo, Pedro; Caldeira, Paulo; Sousa, A.; Duarte, Maria A.; Avila, Filipa; Silva, Joao; Moleiro, Joana; Mendes, Sofia; Giestas, Silvia; Ministro, Paula; Sousa, Paula; Goncalves, Raquel; Goncalves, Bruno; Oliveira, Ana; Rosa, Isadora; Rodrigues, Marta; Chagas, Cristina; Dias, Claudia Camila; Afonso, Joana; Geboes, Karel; Carneiro, FatimaObjective Histological remission is being increasingly acknowledged as a therapeutic endpoint in patients with UC. The work hereafter described aimed to evaluate the concordance between three histological classification systems-Geboes Score (GS), Nancy Index (NI) and RobartsHistopathologyIndex (RHI), as well as to evaluate their association with the endoscopic outcomes and the faecal calprotectin (FC) levels. Design Biopsy samples from 377 patients with UC were blindly evaluated using GS, NI and RHI. The results were compared with the patients' Mayo Endoscopic Score and FC levels. Result GS, NI and RHI have a good concordance concerning the distinction between patients in histological remission or activity. RHI was particularly close to NI, with 100% of all patients classified as being in remission with NI being identified as such with RHI and 100% of all patients classified as having activity with RHI being identified as such with NI. These scores could also predict the Mayo Endoscopic Score and the FC levels, with their sensitivity and specificity levels depending on the chosen cut-offs. Moreover, higher FC levels were statistically associated with the presence of neutrophils in the epithelium, as well as with ulceration or erosion of the intestinal mucosa. Conclusions GS, NI and RHI histopathological scoring systems are comparable in what concerns patients' stratification into histological remission/activity. Additionally, FC levels are increased when neutrophils are present in the epithelium and the intestinal mucosa has erosions or ulcers. The presence of neutrophils in the epithelium is, indeed, the main marker of histological activity.
- Effects of CO2 enrichment on photosynthesis, growth, and nitrogen metabolism of the seagrass Zostera noltiiPublication . Alexandre, Ana; Silva, Joao; Buapet, Pimchanok; Bjork, Mats; Santos, RuiSeagrass ecosystems are expected to benefit from the global increase in CO2 in the ocean because the photosynthetic rate of these plants may be C-i-limited at the current CO2 level. As well, it is expected that lower external pH will facilitate the nitrate uptake of seagrasses if nitrate is cotransported with H+ across the membrane as in terrestrial plants. Here, we investigate the effects of CO2 enrichment on both carbon and nitrogen metabolism of the seagrass Zostera noltii in a mesocosm experiment where plants were exposed for 5 months to two experimental CO2 concentrations (360 and 700 ppm). Both the maximum photosynthetic rate (Pm) and photosynthetic efficiency (alpha) were higher (1.3- and 4.1-fold, respectively) in plants exposed to CO2-enriched conditions. On the other hand, no significant effects of CO2 enrichment on leaf growth rates were observed, probably due to nitrogen limitation as revealed by the low nitrogen content of leaves. The leaf ammonium uptake rate and glutamine synthetase activity were not significantly affected by increased CO2 concentrations. On the other hand, the leaf nitrate uptake rate of plants exposed to CO2-enriched conditions was fourfold lower than the uptake of plants exposed to current CO2 level, suggesting that in the seagrass Z. noltii nitrate is not cotransported with H+ as in terrestrial plants. In contrast, the activity of nitrate reductase was threefold higher in plant leaves grown at high-CO2 concentrations. Our results suggest that the global effects of CO2 on seagrass production may be spatially heterogeneous and depend on the specific nitrogen availability of each system. Under a CO2 increase scenario, the natural levels of nutrients will probably become limiting for Z. noltii. This potential limitation becomes more relevant because the expected positive effect of CO2 increase on nitrate uptake rate was not confirmed.
- Multi-level phenotypic plasticity and the persistence of seagrasses along environmental gradients in a subtropical lagoonPublication . Bercovich, Manuel Vivanco; Schubert, Nadine; Almeida Saa, Antonella C.; Silva, Joao; Horta, Paulo A.As seagrasses decline worldwide, determining their phenotypic variability in response to human altered environmental factors becomes important to better understand their acclimation strategies. Many studies have reported seagrass responses to environmental gradients of single parameters, using either single or multiple metrics. However, studies of species' phenotypic variations along environmental gradients that include several environmental factors are rather scarce. In this study, we evaluated and compared the responses of Halodule wrightii and Ruppia maritima at different organizational levels (meadow/shoot, leaf and biochemical level) to key environmental factors, such as urbanization, light availability, salinity and sediment characteristics in a subtropical Brazilian coastal lagoon. Both species tolerated the variable environmental conditions across the lagoon, but showed species-specific differences in the adjustments at certain organizational levels. Halodule wrightii, an opportunistic species, expressed phenotypic responses mostly at the meadows/shoot and biochemical level, while the colonizer R. maritima exhibited phenotypic variability mostly constrained to the biochemical level. Also, determinations on a few selected meadows showed species-specific photosynthetic responses to environmental conditions. These differences might be related to the species' life history, with R. maritima performing adjustments at organizational levels with a fast response time, while the longer life span of H. wrightii makes also investments in modifications at the shoot and meadow level useful. Thus, this study demonstrates differences in seagrass acclimation strategies in response to environmental variability and, as a first study in this region, it also provides useful baseline data that will allow detecting potential changes and/or deterioration of the habitat.