37 research outputs found

    Size–Abundance Relationships of Freshwater Macroinvertebrates in Two Contrasting Floodplain Channels of Rhone River

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    Body size is perhaps the most fundamental property of an organism and its relationship with abundance is one of the most studied relationships in ecology. Although numerous studies have examined these relationships in local communities, few have investigated how they vary at different temporal and spatial scales. We investigated the relationship between body size and abundance of local macroinvertebrate communities in two floodplain channels of the French upper Rhone River. The two channels differ in their vegetation coverage (high vs. low vegetation) and hydrological regimes. The shapes of the size–abundance relationship were similar between channels on a yearly basis but differed when compared between months. The variation in local size–abundance relationships between months was related to variation in the functional diversity across time. Our findings suggest that local size–abundance relationships are able to quantitatively describe temporal changes in community structure, showing the importance of relating diversity with ecosystem function in a more realistic context

    Variation of leaf litter decomposition among rivers, lagoons and sea: an experiment from Corfu island (Greece)

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    In aquatic ecosystems, the decomposition of organic detritus represents one of the most important ecosystem functions, which support complex detritus-based food webs that determine the critical balance between carbon mineralization and sequestration. The performance of the decomposition process is usually expressed as rate of decomposition, being a synthetic measure that take into account both abiotic and biotic factors. Decomposition rates have been also applied to evaluate the ecological status in terms of ecological functionality. However, despite a growing number of studies have tested the rate of decomposition between leaves of different riparian tree species in different aquatic ecosystems including rivers, transitional waters and sea, no comparative study among ecosystems typology is available up to date. Here, we compare decomposition rates from rivers, lagoons and sea of Corfu island (Greece). Five sampling sites were fixed in each of the three of the most important rivers and lagoons; other five sampling sites were fixed in the sea around the island. Twelve leaf packs containing 3±0.005 g of oven-dried Phragmites australis leaves were submerged in April 2014 and retrieved in May 2014 (after 30 days). Abiotic parameters were recorded in both sampling times. The retrieved leaf packs were cleaned and the macroinvertebrates retained were removed, counted, identified at lower taxonomic level and weighted. Leaf pack decomposition rates were calculated, and their variability was compared within each aquatic ecosystem, within each ecosystem typology (river, lagoon, sea) and among ecosystem typology. The results are going to be presented on the poster

    Ante-mortem and Post-mortem Inspection and Relationship between Findings in a North Albanian Pig Slaughterhouse

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    Simple Summary In European Union abattoirs, the safety of meat is dependent on the favorable opinion from an official veterinarian, in accordance with the current legislation. From this perspective, the feedback generated from the ante-mortem visit and the post-mortem inspection can be investigated to control the health and welfare conditions of the animals in the pre-slaughter phases. From this perspective, we evaluated the ante-mortem and post-mortem inspection outcomes of slaughtered pigs in northern Albania and correlated the results in order to gain insight into the conditions and injuries of pigs slaughtered outside the European context and to extend knowledge on the possible relationship between ante-mortem and post-mortem relief. Dyspnea and tail, skin, and ear lesions were the most frequently observed conditions before slaughter, while pleuritis, pneumonia, liver alterations, white spots on the liver, and pericarditis were the most frequent lesions after slaughter. A significant increase in the total number of post-mortem findings was also observed as the number of ante-mortem findings increased. Overall, the prevalence of the findings observed in this study falls within the broad range of the data in the literature, but additional information should be collected during meat inspection so as to better understand the relationship between ante- and post-mortem outcomes. In June 2014, Albania was granted EU candidate status, thus starting a process of compliance with the membership criteria. In this context, a modern meat inspection approach in line with the European legislation was applied to a pig slaughterhouse in northern Albania in order to investigate the ante-mortem (AM) and post-mortem (PM) conditions and the relationship between these findings. For this purpose, 3930 pigs divided into 35 batches were evaluated over a 3-month period. The most frequent AM conditions recorded were tail lesions and dyspnea (9.1%), followed by skin (8.9%) and ear lesions (8.5%), while in the PM inspections, pleuritis was the most frequently observed condition (10.2%), followed by pneumonia (8.5%), liver alterations (5.7%), milk spot liver (3.8%), and pericarditis (3.3%). With the exception of liver alterations, the other PM lesions mentioned were positively associated with lesions on the ears (OR = 1.036; p < 0.001) and skin (OR = 1.026; p = 0.011) and dyspnea (OR = 1.021; p = 0.005), confirming the link between these variables and the health and welfare conditions of pigs on farms. Overall, the evidence that emerged from this Albanian slaughterhouse can be considered in line with other European contexts, especially in light of the considerable variability in the data present in the literature

    Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

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    Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

    Specific synaptic input strengths determine the computational properties of excitation-inhibition integration in a sound localization circuit

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    During the computation of sound localization, neurons of the lateral superior olive (LSO) integrate synaptic excitation arising from the ipsilateral ear with inhibition from the contralateral ear. We characterized the functional connectivity of the inhibitory and excitatory inputs onto LSO neurons in terms of unitary synaptic strength and convergence. Unitary IPSCs can generate large conductances, although their strength varies over a 10-fold range in a given recording. By contrast, excitatory inputs are relatively weak. The conductance associated with IPSPs needs to be at least 2-fold stronger than the excitatory one to guarantee effective inhibition of action potential (AP) firing. Computational modelling showed that strong unitary inhibition ensures an appropriate slope and midpoint of the tuning curve of LSO neurons. Conversely, weak but numerous excitatory inputs filter out spontaneous AP firing from upstream auditory neurons.The lateral superior olive (LSO) is a binaural nucleus in the auditory brainstem in which excitation from the ipsilateral ear is integrated with inhibition from the contralateral ear. It is unknown whether the strength of the unitary inhibitory and excitatory inputs is adapted to allow for optimal tuning curves of LSO neuron action potential (AP) firing. Using electrical and optogenetic stimulation of afferent synapses, we found that the strength of unitary inhibitory inputs to a given LSO neuron can vary over a ∼10-fold range, follows a roughly log-normal distribution, and, on average, causes a large conductance (9 nS). Conversely, unitary excitatory inputs, stimulated optogenetically under the bushy-cell specific promoter Math5, were numerous, and each caused a small conductance change (0.7 nS). Approximately five to seven bushy cell inputs had to be active simultaneously to bring an LSO neuron to fire. In double stimulation experiments, the effective inhibition window caused by IPSPs was short (1-3 ms) and its length depended on the inhibitory conductance; an ∼2-fold stronger inhibition than excitation was needed to suppress AP firing. Computational modelling suggests that few, but strong, unitary IPSPs create a tuning curve of LSO neuron firing with an appropriate slope and midpoint. Furthermore, weak but numerous excitatory inputs reduce the spontaneous AP firing that LSO neurons would otherwise inherit from their upstream auditory neurons. Thus, the specific connectivity and strength of unitary excitatory and inhibitory inputs to LSO neurons is optimized for the computations performed by these binaural neurons

    Ceramide in beta cells apoptosis induced by gluco-lipotoxicity:possible role of cer flow for the biosynthesis of complex sphingolipids

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    CERAMIDE IN BETA CELLS APOPTOSIS INDUCED BY GLUCO-LIPOTOXICITY: POSSIBLE ROLE OF CER FLOW FOR THE BIOSYNTHESIS OF COMPLEX SPHINGOLIPIDS P. Giussani1, H. Le Stunff2, E. Gjoni1, J. Veret2, L. Riboni1, P. Viani1 1Department of Medical Chemistry, Biochemistry and Biotechnology, University of Milano, LITA Segrate, Via Fratelli Cervi, 93, 20090 Segrate (MI) Italy 2Unit\ue9 Biologie Fonctionnelle et Adaptative - EAC CNRS 4413, Laboratoire de Biologie et Pathologie du Pancr\ue9as Endocrine, Universit\ue9 PARIS- DIDEROT (7),4, rue Marie-Andr\ue9e Lagroua Weill-Halle, 75205 PARIS Cedex 13 France Background: In type 2 diabetes the detrimental effects of chronic exposure to NEFA, in particular palmitate, on beta cell function and viability have been correlated to hyperglycaemia. De novo synthesis of ceramide (Cer) and ER stress are among the molecular pathways and regulators involved in these negative effects. In order to gain insight into the molecular mechanism(s) of gluco-lipotoxicity we studied the effect of palmitate and high glucose concentrations on ceramide metabolism in INS-1 cells. Results: The results obtained demonstrated that in INS-1 cells palmitate and glucose taken separately did not induce cell death, whereas the combined treatment with both nutrients resulted in an extensive cell apoptosis and this was associated to a significant increase of Cer levels. The presence of fumonisin-B1 partially reversed the apoptosis induced by the combined treatment with palmitate and glucose thus suggesting a role for ER-associated Cer in gluco-lipotoxicity in INS-1 cells. Metabolic studies show that treatment with palmitate results in the inhibition of Cer utilization for SM biosynthesis. Fluorescence microscopy studies suggest a reduced ER to Golgi flow of Cer. To evaluate if Cer accumulation could be due to a defect in the vesicular and/or CERT-mediated transport of Cer, we studied Cer metabolism in INS-1 cells silenced for CERT incubated with glucose in the presence or not of palmitate. In downregulated cells palmitate inhibited Cer utilization for SM biosynthesis; these results indicated that the vesicle-mediated transport is involved in the reduced ER to Golgi flow of Cer. Conclusions: Altogether these data suggest that the accumulation of Cer can be due to a decrease in utilization of newly synthesized Cer for SM biosynthesis thus supporting a role of ER-associated Cer in the regulation of beta cell death induced by gluco-lipotoxicity
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