Are we building too many arteriovenous fistulas? A single-center experience

Introduction: Arteriovenous fistula has been associated with improved morbimortality in hemodialysis patients. This has resulted in the “fistula First, catheter last” initiative. Nonetheless, the survival benefit of arteriovenous fistula has been questioned. Methods: We conducted a retrospective observational study of all patients with non-end stage renal disease referred for first vascular access building between January 2014 and December 2015 in our hospital center. Our main goal was to evaluate the clinical impact and burden of building fistula in predialysis patients. Results: During this period, of 178 first arteriovenous accesses placed, 87 patients remained in predialysis and 91 patients started a chronic hemodialysis program. Median follow-up time by a nephrologist was 3.9 (2.5, 9.7) years. The mean age was 65.8±14.7 years, with 50.6% (n=90) of male patients. A higher rate of thrombosis in the predialysis group (26% vs 13%, p=0.037) was observed, but vascular access survival did not differ significantly (55% vs 67%, p=0.12). Mean vascular access placing was higher in the predialysis group (1.4±0.7 vs 1.2±0.4, p=0.006) and less interventions were requested (0.2±0.5 vs 0.3±0.6, p=0.10). Median time from vascular access placement to hemodialysis start was 22 (13, 41) months. At hemodialysis initiation, 10 (10.9%) patients used a central venous catheter; 80 (87.9%) patients an arteriovenous fistula, and one patient a graft. A total of 227 vascular accesses were built; 121 (53.3%) in predialysis vs 106 (46.7%) in incident hemodialysis patients. In a multivariate model, the presence of a functional arteriovenous fistula at hemodialysis start was only associated with a trend to survival benefit (HR 0.38, 95% CI 0.14-1.00, p=0.05). Conclusions: Our results stress the need for an individual approach and for future tools to assess the risk of death and progression to end-stage renal disease, therefore helping reduce the number of unutilized vascular accesses and rising cost of interventions.info:eu-repo/semantics/publishedVersio

A differential method for bounding the ground state energy

For a wide class of Hamiltonians, a novel method to obtain lower and upper bounds for the lowest energy is presented. Unlike perturbative or variational techniques, this method does not involve the computation of any integral (a normalisation factor or a matrix element). It just requires the determination of the absolute minimum and maximum in the whole configuration space of the local energy associated with a normalisable trial function (the calculation of the norm is not needed). After a general introduction, the method is applied to three non-integrable systems: the asymmetric annular billiard, the many-body spinless Coulombian problem, the hydrogen atom in a constant and uniform magnetic field. Being more sensitive than the variational methods to any local perturbation of the trial function, this method can used to systematically improve the energy bounds with a local skilled analysis; an algorithm relying on this method can therefore be constructed and an explicit example for a one-dimensional problem is given.Comment: Accepted for publication in Journal of Physics

On the influence of thermal hysteresis on the performance of thermomagnetic motors

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQAlthough thermal hysteresis might be a problem in the magnetocaloric refrigeration, the same is not necessarily true for thermomagnetic motor applications. This work presents a comparison of the magnetocaloric properties of materials with first order magnetic transition (having large or narrow thermal hysteresis) to those with second order magnetic transition, assessing the application of these materials in thermomagnetic motors through a thermodynamic approach. Results show that the larger the thermal hysteresis, the higher the specific work produced in a thermal cycle. This allows operation at higher temperature differences with high efficiency relative to Carnot efficiency, when compared with systems using narrow hysteresis and second order transition materials.1222415FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ2015/26799-0Sem informaçã

Effect of oral anticoagulants on the outcome of faecal immunochemical test

Background: We aimed to evaluate whether oral anticoagulants (OACs) alter faecal immunochemical test (FIT) performance in average-risk colorectal cancer (CRC) screening. Methods: Individuals aged 50–69 years were invited to receive one FIT sample (cutoff 75¿ng¿ml–1) between November 2008 and June 2011. Results: Faecal immunochemical test was positive in 9.3% (21 out of 224) of users of OAC and 6.2% (365 out of 5821) of non-users (P-trend=0.07). The positive predictive value (PPV) for advanced neoplasia (AN) in non-users was 50.4% vs 47.6% in users (odds ratio, 0.70; 95% CI, 0.3–1.8; P=0.5). The PPV for AN in OAC more antiplatelets (aspirin or clopidogrel) was 75% (odds ratio, 2; 95% CI, 0.4–10.8; P=0.4). Conclusions: Oral anticoagulant did not significantly modify the PPV for AN in this population-based colorectal screening program. The detection rate of advanced adenoma was higher in the combination OAC more antiplatelets

Detailed dimethylacetal and fatty acid composition of rumen content from lambs fed lucerne or concentrate supplemented with soybean oil

Articles in International JournalsLipid metabolism in the rumen is responsible for the complex fatty acid profile of rumen outflow compared with the dietary fatty acid composition, contributing to the lipid profile of ruminant products. A method for the detailed dimethylacetal and fatty acid analysis of rumen contents was developed and applied to rumen content collected from lambs fed lucerne or concentrate based diets supplemented with soybean oil. The methodological approach developed consisted on a basic/ acid direct transesterification followed by thin-layer chromatography to isolate fatty acid methyl esters from dimethylacetal, oxo- fatty acid and fatty acid dimethylesters. The dimethylacetal composition was quite similar to the fatty acid composition, presenting even-, odd- and branched-chain structures. Total and individual odd- and branched-chain dimethylacetals were mostly affected by basal diet. The presence of 18:1 dimethylacetals indicates that biohydrogenation intermediates might be incorporated in structural microbial lipids. Moreover, medium-chain fatty acid dimethylesters were identified for the first time in the rumen content despite their concentration being relatively low. The fatty acids containing 18 carbon-chain lengths comprise the majority of the fatty acids present in the rumen content, most of them being biohydrogenation intermediates of 18:2n26 and 18:3n23. Additionally, three oxo- fatty acids were identified in rumen samples, and 16-O-18:0 might be produced during biohydrogenation of the 18:3n23

A despistagem do VIH/sida: saúde pública e motivações dos utentes do teste rápido no Nordeste de Portugal

The article examines the adherence of citizens to the quick test for HIV in the Counseling and Early Detection of HIV/AIDS Center (CAD), in the city of Bragança (Northeast Portugal). Specifically, it seeks to examine the role of a fast diagnosis in the fight against AIDS within the Portuguese public health system, to understand the circumstances underlying the demand for the service and to interpret the perceptions and practices of CAD users. In terms of methodology, it was a case study based on ethnographic inquiry, linking direct observation, informal conversations and interviews, which was associated with extensive documental and statistic research. The results obtained allow us to state that the quick test gave a very positive contribution to the fight against HIV/AIDS infection, facilitating citizen access to knowledge of their serological status almost instantly and improving their follow-up by health technicians. The so-called “dissipation of uncertainty”, following sexual risk behavior, is the main reason that leads users to perform a quick test.O artigo analisa a adesão dos cidadãos ao teste rápido de despistagem do VIH no Centro de Aconselhamento e Deteção Precoce do VIH/sida (CAD) da cidade de Bragança (Nordeste de Portugal). Em concreto, procura-se examinar o papel do diagnóstico rápido na luta contra a infeção pelo VIH/sida no quadro do sistema público de saúde português, compreender as circunstâncias subjacentes à procura do serviço e interpretar as percepções e práticas dos utentes do CAD objecto desta pesquisa. Em termos metodológicos, tratou-se de um estudo de caso assente em inquirição etnográfica, articulando observação direta, diálogos informais e entrevistas, a que se associou uma extensa pesquisa documental e estatística. Os resultados apurados permitem afirmar que o teste rápido proporcionou um contributo muito positivo para a luta contra a infeção pelo VIH/sida, facilitando o acesso dos cidadãos ao conhecimento praticamente imediato do seu estado serológico e melhorando o seguimento destes por parte dos técnicos de saúde. A chamada “dissipação da incerteza”, na sequência de uma situação de risco, é o principal motivo que leva os utentes a realizar o teste rápido

The impact of chronic stress on the rat brain lipidome

Chronic stress is a major risk factor for several human disorders that affect modern societies. The brain is a key target of chronic stress. In fact, there is growing evidence indicating that exposure to stress affects learning and memory, decision making and emotional responses, and may even predispose for pathological processes, such as Alzheimer's disease and depression. Lipids are a major constituent of the brain and specifically signaling lipids have been shown to regulate brain function. Here, we used a mass spectrometry-based lipidomic approach to evaluate the impact of a chronic unpredictable stress (CUS) paradigm on the rat brain in a region-specific manner. We found that the prefrontal cortex (PFC) was the area with the highest degree of changes induced by chronic stress. Although the hippocampus presented relevant lipidomic changes, the amygdala and, to a greater extent, the cerebellum presented few lipid changes upon chronic stress exposure. The sphingolipid and phospholipid metabolism were profoundly affected, showing an increase in ceramide (Cer) and a decrease in sphingomyelin (SM) and dihydrosphingomyelin (dhSM) levels, and a decrease in phosphatidylethanolamine (PE) and ether phosphatidylcholine (PCe) and increase in lysophosphatidylethanolamine (LPE) levels, respectively. Furthermore, the fatty-acyl profile of phospholipids and diacylglycerol revealed that chronic stressed rats had higher 38 carbon(38C)-lipid levels in the hippocampus and reduced 36C-lipid levels in the PFC. Finally, lysophosphatidylcholine (LPC) levels in the PFC were found to be correlated with blood corticosterone (CORT) levels. In summary, lipidomic profiling of the effect of chronic stress allowed the identification of dysregulated lipid pathways, revealing putative targets for pharmacological intervention that may potentially be used to modulate stress-induced deficits.Funding by Fundação para a Ciência e Tecnologia (PTDC/SAU-NMC/118971/2010) and by the North Region Operational Program (ON.2-O Novo Norte), under Quadro de Referência Estratégico Nacional (QREN) and through Fundo Europeu de Desenvolvimento Regional (FEDER). GDP is funded by NIH grants R01 NS056049 and P50 AG008702 (to Scott Small)

AP2γ controls adult hippocampal neurogenesis and modulates cognitive, but not anxiety or depressive-like behavior

Hippocampal neurogenesis has been proposed to participate in a myriad of behavioral responses, both in basal states and in the context of neuropsychiatric disorders. Here, we identify activating protein 2γ 3 (AP2γ 3, also known as Tcfap2c), originally described to regulate the generation of neurons in the developing cortex, as a modulator of adult hippocampal glutamatergic neurogenesis in mice. Specifically, AP2γ 3 is present in a sub-population of hippocampal transient amplifying progenitors. There, it is found to act as a positive regulator of the cell fate determinants Tbr2 and NeuroD, promoting proliferation and differentiation of new glutamatergic granular neurons. Conditional ablation of AP2γ 3 in the adult brain significantly reduced hippocampal neurogenesis and disrupted neural coherence between the ventral hippocampus and the medial prefrontal cortex. Furthermore, it resulted in the precipitation of multimodal cognitive deficits. This indicates that the sub-population of AP2γ 3-positive hippocampal progenitors may constitute an important cellular substrate for hippocampal-dependent cognitive functions. Concurrently, AP2γ 3 deletion produced significant impairments in contextual memory and reversal learning. More so, in a water maze reference memory task a delay in the transition to cognitive strategies relying on hippocampal function integrity was observed. Interestingly, anxiety- and d epressive-like behaviors were not significantly affected. Altogether, findings open new perspectives in understanding the role of specific sub-populations of newborn neurons in the (patho)physiology of neuropsychiatric disorders affecting hippocampal neuroplasticity and cognitive function in the adult brain.We acknowledge the excellent technical expertise of Luís Martins and Andrea Steiner-Mezzadri. We would also like to acknowledge Magdalena Götz for the insightful comments on the paper. AMP, PP, ARS, JS, VMS, NDA and JFO received fellowships from the Portuguese Foundation for Science and Technology (FCT). LP received fellowship from FCT and her work is funded by FCT (IF/01079/2014) and Bial Foundation (427/14) projects. This work was cofunded by the Life and Health Sciences Research Institute (ICVS), and Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) (projects NORTE-01-0145- FEDER-000013 and NORTE-01-0145-FEDER-000023). This work has been also funded by FEDER funds, through the Competitiveness Factors Operational Programme (COMPETE), and by National funds, through the FCT, under the scope of the project POCI-01-0145-FEDER-007038info:eu-repo/semantics/publishedVersio