There is controversy as to whether vitamin E is beneficial in Alzheimer's disease (AD). In this study, we tested if vitamin E prevents oxidative stress and loss of cognition in AD. Fifty-seven AD patients were recruited and divided in two groups: placebo or treated with 800 IU of vitamin E per day for six months. Of these 57 patients, only 33 finished the study. We measured blood oxidized glutathione (GSSG) and used the following cognitive tests: Mini-Mental State Examination, Blessed-Dementia Scale, and Clock Drawing Test. Of those patients treated with vitamin E, we found two groups. In the first group, "respondents" to vitamin E, GSSG levels were lower after the treatment and scores on the cognitive tests were maintained. The second group, "non-respondents", consisted of patients in which vitamin E was not effective in preventing oxidative stress. In these patients, cognition decreased sharply, to levels even lower than those of patients taking placebo. Based on our findings, it appears that vitamin E lowers oxidative stress in some AD patients and maintains cognitive status, however, in those in which vitamin E does not prevent oxidative stress, it is detrimental in terms of cognition. Therefore, supplementation of AD patients with vitamin E cannot be recommended without determination of its antioxidant effect in each patient.

BackgroundGlutathione is considered essential for survival in mammalian cells and yeast but not in prokaryotic cells. The presence of a nuclear pool of glutathione has been demonstrated but its role in cellular proliferation and differentiation is still a matter of debate.Principal FindingsWe have studied proliferation of 3T3 fibroblasts for a period of 5 days. Cells were treated with two well known depleting agents, diethyl maleate (DEM) and buthionine sulfoximine (BSO), and the cellular and nuclear glutathione levels were assessed by analytical and confocal microscopic techniques, respectively. Both agents decreased total cellular glutathione although depletion by BSO was more sustained. However, the nuclear glutathione pool resisted depletion by BSO but not with DEM. Interestingly, cell proliferation was impaired by DEM, but not by BSO. Treating the cells simultaneously with DEM and with glutathione ethyl ester to restore intracellular GSH levels completely prevented the effects of DEM on cell proliferation.ConclusionsOur results demonstrate the importance of nuclear glutathione in the control of cell proliferation in 3T3 fibroblasts and suggest that a reduced nuclear environment is necessary for cells to progress in the cell cycle.

The food habits of the beaked skate were studied utilising 274 individuals obtained from the incidental catches of the Argentine hake (Merluccius hubbsi) fishery. The most important prey were the Argentine hake, the southern cod (Patagonotothen ramsayi), the Argentine shortfin squid (Illex argentinus), the isopod (Serolis schythei), the ''raneya'' (Raneya brasiliensis, Pisces: Ophidiidae), and the Argentine anchovy (Engraulis anchoita). A total of 45 prey species was identified. No differences in the diet between sexes, but significant differences among size classes and between immature and mature individuals were found. Two size-related dietary shifts previously reported in this species, at around 35 cm and 85 cm total length were confirmed and related to changes in habitat utilisation. The first shift entails a major change from benthic prey (mostly crustaceans) to demersal-benthic prey (mostly fishes) and the second change from demersal-benthic to demersal-pelagic prey (increased consumption of Argentine hake and decreased consumption of southern cod). The second shift coincides with sexual maturation and may reflect a behavioural response to maturation. International Council for the Exploration of the Sea