A two-hybrid screening of human Tau protein: interactions with Alu-derived domain

The microtubule associated protein tau has been implicated in several neurodegenerative diseases, grouped as tauopathies. To search for tau-associated proteins, the two-hybrid system was used with tau as a bait and an adult human brain cDNA library as a source of putative interacting proteins. We have identified two positive clones consisting of an Alu-derived amino acid sequence that binds to tau and show moderate homology with a motif found in several neuronal proteins related to neurodegenerative disorders. We have also demonstrated that the Alu-derived motif interacts in vitro with tau and may be involved in modulation of its phosphorylation. These findings suggest the existence of tau-binding proteins that are able to bind to tau through their Alu-derived sequence in a direct way. The possible interaction of these proteins with tau could play a role in its cellular localization, regulate the amount of phosphorylated tau and also be involved in the pathological processes of tauopathies.     

Vascular endothelial growth factor plasma levels in patients with systemic lupus erythematosus and primary antiphospholipid syndrome

The objective of this study was to assess the possible role of vascular endothelial growth factor (VEGF) in the pathogenesis of systemic lupus erythematosus (SLE) and primary antiphospholipid syndrome (PAPS). We studied 28 patients with SLE, 10 patients with PAPS, and 24 healthy controls. VEGF plasma levels were measured by ELISA. Immunolocalization of VEGF was done in renal tissue from SLE patients and cadaveric controls. Our results showed that VEGF plasma levels were increased in SLE patients compared with PAPS and controls. The correlation between clinical manifestations and VEGF levels revealed that SLE patients with renal failure had significantly increased plasma VEGF levels (134.1 + 91.0 pg/ml) compared with SLE patients with normal renal function (42.9 + 19.0 pg/ml), PAPS patients (41.9 + 26.6 pg/ml), and controls (36.2 + 27.0 pg/ml; P < 0.01). Immunostaining showed a strong expression of VEGF in SLE renal tissue samples. Our preliminary results indicate that VEGF is increased in plasma from patients with lupus nephritis and a moderate degree of renal failure and is overexpressed in renal tissue from these patients.     

Reactive oxygen: its sources and significance in Alzheimer disease

Over the past decade, oxidative stress has been established as the earliest cytological feature of Alzheimer disease and an attractive therapeutic target. The major challenges now are establishing the source of the reactive oxygen and what oxidative stress tells us about the etiology of Alzheimer disease. These are complex issues since a variety of enzymatic and non-enzymatic processes are involved in reactive oxygen formation and damage to macromolecules. In this review, we consider disease mechanisms that show the greatest promise for future research.     

Otitis media with effusion: expectant management

OBJECTIVE: Despite the fact that chronic otitis media with effusion (OME) is an entity with a high prevalence among children, the real effectiveness of most treatments in use nowadays has not been completely established. Based on its natural course, we defend an expectant management as the initial treatment. METHODS: We undertook a review of the available data taking into consideration the natural history, epidemiology and therapeutic options for OME. We looked for a guideline concerning the best treatment for OME in children. RESULTS: The treatment of OME still remains controversial, in spite of many therapeutic options. In children, the best management still seems to be the observation, probably for a period of three to six months. However, interventionist treatment should be done earlier on those patients considered as high risk or in which a problem happened with their development, due to hearing loss secondary to OME. CONCLUSIONS: The understanding of the several factors involved in the pathogenesis of OME, as well as of the features in its evolutive course, encourage the idea of a conservative expectant approach at first or up to the moment in which an interventionist approach (clinical or surgical) is justified.     

Chemical composition and biological activity of extracts from arrabidaea bilabiata

Consumption of Arrabidaea bilabiata fresh leaves produces a paraplegic syndrome in cattle. For isolation of the active principle, isopropanol and methanol extracts were prepared from the aerial parts of the plant; these were administered to Sprague-Dawley rats at doses of 0.5, 1, and 2 mg/kg, orally, to determine the presence of substances affecting spontaneous motor activity. The isopropanol extract produced significant increases of long-pause and short-pause movements (112 and 54%, respectively). The methanol extract tended to increase motor activity, but the effect did not reach statistical significance. Chemical and spectroscopic analysis of the isopropanol extract showed allantoin was the major constituent. It was administered to rats, at doses of 1.2, 12, and 120 mg/kg. A complex dose-response curve was observed, but at the highest dose, there was a 52% increase in the number of long-pause movements. It was inferred that allantoin and the constituents of the alcholic extracts might not be responsible for the paraplegic synndrome in cattle. The alteration of cattle motor activity could be caused by other non-alcoholic constituents. Additionally, extracts were assayed for in vitro activity against Escherichia coli , Klebsiella pneumonae , Pseudomonas aeruginosa , Staphylococcus aureus , Bacillus sp. and Candida albicans . All microbial strains were found to be resistant to the extracts with the exception of C. albicans , suggesting a possible antifungal activity.