Tg2576 Cortical Neurons That Express Human Ab Are Susceptible to Extracellular Aβ-Induced, K+ Efflux Dependent Neurodegeneration

Background: One of the key pathological features of AD is the formation of insoluble amyloid plaques. The major constituent of these extracellular plaques is the beta-amyloid peptide (Aβ), although Aβ is also found to accumulate intraneuronally in AD. Due to the slowly progressive nature of the disease, it is likely that neurons are exposed to sublethal concentrations of both intracellular and extracellular Aβ for extended periods of time. Results: In this study, we report that daily exposure to a sublethal concentration of Aβ1-40 (1 μM) for six days induces substantial apoptosis of cortical neurons cultured from Tg2576 mice (which express substantial but sublethal levels of intracellular Aβ). Notably, untreated Tg2576 neurons of similar age did not display any signs of apoptosis, indicating that the level of intracellular Aβ present in these neurons was not the cause of toxicity. Furthermore, wildtype neurons did not become apoptotic under the same chronic Aβ1-40 treatment. We found that this apoptosis was linked to Tg2576 neurons being unable to maintain K⁺ homeostasis following Aβ treatment. Furthermore, blocking K⁺ efflux protected Tg2576 neurons from Aβ-induced neurotoxicity. Interestingly, chronic exposure to 1 μM Aβ1-40 caused the generation of axonal swellings in Tg2576 neurons that contained dense concentrations of hyperphosphorylated tau. These were not observed in wildtype neurons under the same treatment conditions. Conclusions: Our data suggest that when neurons are chronically exposed to sublethal levels of both intra- and extra-cellular Aβ, this causes a K⁺-dependent neurodegeneration that has pathological characteristics similar to AD.9 page(s

Interaction of Hydrogen with Graphitic Surfaces, Clean and Doped with Metal Clusters

Producción CientíficaHydrogen is viewed as a possible alternative to the fossil fuels in transportation. The technology of fuel-cell engines is fully developed, and the outstanding remaining problem is the storage of hydrogen in the vehicle. Porous materials, in which hydrogen is adsorbed on the pore walls, and in particular nanoporous carbons, have been investigated as potential onboard containers. Furthermore, metallic nanoparticles embedded in porous carbons catalyze the dissociation of hydrogen in the anode of the fuel cells. For these reasons the interaction of hydrogen with the surfaces of carbon materials is a topic of high technological interest. Computational modeling and the density functional formalism (DFT) are helping in the task of discovering the basic mechanisms of the interaction of hydrogen with clean and doped carbon surfaces. Planar and curved graphene provide good models for the walls of porous carbons. We first review work on the interaction of molecular and atomic hydrogen with graphene and graphene nanoribbons, and next we address the effects due to the presence of metal clusters on the surface because of the evidence of their role in enhancing hydrogen storage.Ministerio de Economía, Industria y Competitividad (Grant MAT2014-54378-R

Características del ensilaje de pasto Taiwán adicionando diversas fuentes de nitrógeno.

El Taiwán (Pennisetum purpureum var. 144) es un forraje de corte que alcanza una altura de 3.5 metros. En la zona henquenera del estado de Yucatán bajo condiciones de riego se han obtenido en cuatro cortes al año de 150 a 200 ton. de forraje verde por he

Adjusted global antiphospholipid syndrome score (aGAPSS) is useful to predict relapses in patients with retinal vein occlusion

Background A significant proportion of patients with retinal vein occlusion (RVO) are antiphospholipid antibodies (aPL) carriers. Relapsing disease occurs in nearly 10 % of cases and the role of aPL has not been established. The adjusted global antiphospholipid syndrome score (aGAPSS) was developed to assess the risk of clinical events in aPL carriers and its role in the management of RVO patients is unknown. Objective To analyze the values of aGAPSS in a large cohort of patients with RVO and population-based controls, and to assess its usefulness to predict RVO relapses. Methods Case-control study of RVO patients and population-based controls of similar age and sex. We have assessed and compared the aPL profile and the aGAPSS score in patients with and without relapsing disease and controls. Results Four-hundred and seventy-two RVO patients and 346 controls were included. Fifty-seven RVO patients had antiphospholipid syndrome (RVO-APS). Of them, 75.4 % had a high-risk profile compared to 3 % in controls (p = 0.0001). The median aGAPSS values were 8 [7?13], 3 [1?4], and 3 [0?4], in RVO-APS, RVO no-APS, and controls. Nineteen patients had had a recurrence of RVO before inclusion and 8 during the follow-up. APS was more prevalent in relapsing patients. In the adjusted multivariable regression model, the best predictor for RVO recurrence during the follow-up was an aGAPSS score ?6 (OR 5.5, CI95% 1.3?23.7; p = 0.023). Conclusions In patients with RVO, once the control of vascular risk factors has been optimized, the aGAPSS might help to identify those at risk of relapsing disease.Sources of funding: The Camargo Cohort Study was supported by a grant from Instituto de Salud Carlos III (PI21/00532) that could be co-funded by European Union FEDER funds