Francisca Martínez Ruiz

Late survival of Neanderthals at the southernmost extreme of Europe

The late survival of archaic hominin populations and their long contemporaneity with modern humans is now clear for southeast Asia. In Europe the extinction of the Neanderthals, firmly associated with Mousterian technology, has received much attention, and evidence of their survival after 35 kyr bp has recently been put in doubt. Here we present data, based on a high-resolution record of human occupation from Gorham’s Cave, Gibraltar, that establish the survival of a population of Neanderthals to 28 kyr bp. These Neanderthals survived in the southernmost point of Europe, within a particular physiographic context, and are the last currently recorded anywhere. Our results show that the Neanderthals survived in isolated refuges well after the arrival of modern humans in Europe.

Cyclosporin A targets involved in protection against glutamate excitotoxicity

The toxicity of glutamate in neuronal cultures has been attributed in part to a mitochondrial dysfunction involving the permeability transition pore. The participation of the permeability transition pore in this process has been pharmacologically demonstrated by the use of cyclosporin A, which inhibits pore opening by interaction with mitochondrial cyclophilin and, thus, prevents cell death and upstream events. Since cyclosporin A also acts on calcineurin, we have investigated which of the targets of cyclosporin A was responsible for the inhibition of glutamate-excitotoxicity in cerebrocortical primary neuronal cultures. Reactive oxygen species production and early (30 min to 2 h) drop in ATP levels are initial events in glutamate excitotoxicity taking place before neuronal death. Cyclosporin A did not inhibit reactive oxygen species production, but reduced the drop in ATP levels and subsequent neuronal death. However, cyclosporin derivatives that do not bind to calcineurin had smaller effect on survival than cyclosporin A, (regardless of whether they were able to bind cyclophilin), indicating that cyclosporin A protects against glutamate toxicity also through calcineurin-related mechanisms. Consistent with this view, ATP loss appears to result from nitric oxide synthase (NOS) activation (including calcineurin-dependent dephosphorylation) and nitric oxide (NO)/peroxinitrite-dependent increase in poly (ADP-ribose) polymerase activity, since it was reduced by inhibitors of these activities. Collectively, these results suggest that cyclosporin A exerts its protective effects through calcineurin-dependent and independent mechanisms.

Pyruvate protection against β‐amyloid‐induced neuronal death: Role of mitochondrial redox state

The mechanism by which β‐amyloid protein (Aβ) causes degeneration in cultured neurons is not completely understood, but several lines of evidence suggest that Aβ‐mediated neuronal death is associated with an enhanced production of reactive oxygen species (ROS) and oxidative damage. In the present study, we address whether supplementation of glucose‐containing culture media with energy substrates, pyruvate plus malate (P/M), protects rat primary neurons from Aβ‐induced degeneration and death. We found that P/M addition attenuated cell death evoked by β‐amyloid peptides (Aβ25–35 and Aβ1–40) after 24 hr treatment and that this effect was blocked by α‐ciano‐3‐hydroxycinnamate (CIN), suggesting that it requires mitochondrial pyruvate uptake. P/M supply to control and Aβ‐treated neuronal cultures increases cellular reducing power, as indicated by the ability to reduce the dye 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT). The early increases in ROS levels, measured by dichlorofluorescein (DCF) fluorescence, and caspase‐3 activity that follow exposure to Aβ were notably reduced in the presence of P/M. These results place activation of caspase‐3 most likely downstream of oxidative damage to the mitochondria and indicate that mitochondrial NAD(P) redox status plays a central role in the neuroprotective effect of pyruvate. Inhibition of respiratory chain complexes and mitochondrial uncoupling did not block the early increase in ROS levels, suggesting that Aβ could initiate oxidative stress by activating a source of ROS that is not accesible to the antioxidant defenses fueled by mitochondrial substrates.

Hemorragia subaracnoidea aneurismática. Introducción a algunos de los aspectos más importantes de esta enfermedad

Resumen Se revisan la epidemiologia, historia natural, metodologia diagnostica y recomendaciones para el tratamiento quirurgico y endovascular de los aneurismas intracraneales. Las recomendaciones propuestas deben considerarse como una guia general de manejo de esta patologia. Sin embargo, pueden ser modificadas, incluso de manera significativa por las circunstancias propias de cada caso clinico, o las variaciones en los recursos diagnosticos y terapeuticos del centro hospitalario que reciba al paciente.

The use of clay minerals and microfossils in palaeoenvironmental reconstructions: The Holocene littoral strand of Las Nuevas (Donana National Park) SW Spain

Abstract Three steps have been established during the Holocene formation of the bar-built estuary of Las Nuevas (Doñana National Park, Spain), on the basis of the clay mineralogy variations and the palaeontological record. The first step is characterized by the presence of ostracodes and homogeneous quantities of clay minerals (17−20% illite, 25−29% smectites), values of smectite (0.64− 0.70) and illite (0.60−0.70) crystallinity indexes, and the ratio of AlVI/(FeVI + MgVI) in illite (0.46− 0.47). This zone is interpreted as a very shallow lagoon with euryhaline conditions. The presence of roots, the progressive disappearance of foraminifers and an increase in the smectite content (up to 35%) define the second step. A salt-marsh environment with low-energy hydrodynamic conditions is deduced for this zone. The third step is characterized by an increase in illite content (up to 35%), and a decrease of the smectite content (up to 21%). The smectite crystallinity index decreased to 0.38, whereas the illite ratio AlVI/(FeVI + MgVI) decreased to 0.36. In this zone, the ostracode assemblage contains numerous juvenile stages of coastal species coinciding with lumachelle accumulations of the estuarine bivalves, abundant foraminifers and the presence of charophytes. This zone represents a strong marine input, probably caused by storms.