Assessing cognitive decline in the aging brain: lessons from rodent and human studies

As life expectancy continues to increase worldwide, age-related dysfunction will largely impact our societies in the future. Aging is well established to promote the deterioration of cognitive function and is the primary risk factor for the development of prevalent neurological disorders. Even in the absence of dementia, age-related cognitive decline impacts specific types of memories and brain structures in humans and animal models. Despite this, preclinical and clinical studies that investigate age-related changes in brain physiology often use largely different methods, which hinders the translational potential of findings. This review seeks to integrate what is known about age-related changes in the brain with analogue cognitive tests used in humans and rodent studies, ranging from "pen and paper" tests to virtual-reality-based paradigms. Finally, we draw parallels between the behavior paradigms used in research compared to the enrollment into clinical trials that aim to study age-related cognitive decline.

Morbidity associated with Schistosoma mansoni infection determined by ultrasound in an endemic area of Brazil, Caatinga do Moura

Morbidity in schistosomiasis is caused by a granulomatous response to Schistosoma mansoni eggs deposited in peripheral portal veins. Ultrasonography has been useful to assess the impact of control programs on the prevalence of hepatic fibrosis. In the present study, ultrasonographic criteria proposed by the World Health Organization were used to classify the degree of hepatic fibrosis in 164 schistosomiasis patients from an endemic area of Brazil. The majority of subjects (89%) had degree I or II hepatic fibrosis. Periportal tract thickness, portal vein diameter, splenic vein diameter, and spleen size were positively correlated (P < 0.01). Ultrasonography was repeated on 21 patients one year later and hepatic fibrosis had progressed in 17. Ultrasonography was performed after treatment on 39 subjects and periportal fibrosis had regressed in 27.

Neurotoxic/neuroprotective profile of carbamazepine, oxcarbazepine and two new putative antiepileptic drugs, BIA 2-093 and BIA 2-024

We investigated and compared the toxicity profile, as well as possible neuroprotective effects, of some antiepileptic drugs in cultured rat hippocampal neurons. We used two novel carbamazepine derivatives, (S)-(-)-10-acetoxy-10,11-dihydro-5H-dibenz[b, f]azepine-5-carboxamide (BIA 2-093) and 10, 11-dihydro-10-hydroxyimino-5H-dibenz[b,f]azepine-5-carboxamide (BIA 2-024), and compared their effects with the established compounds carbamazepine and oxcarbazepine. The assessment of neuronal injury was made by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay, as well as by analysing morphology and nuclear chromatin condensation (propidium iodide staining), after hippocampal neurons were exposed to the drugs for 24 h. The putative antiepileptic drugs, BIA 2-093 or BIA 2-024 (at 300 microM), only slightly decreased MTT reduction, whereas carbamazepine or oxcarbazepine were much more toxic at lower concentrations. Treatment with the antiepileptic drugs caused nuclear chromatin condensation in some neurons, which is characteristic of apoptosis, and increased the activity of caspase-3-like enzymes, mainly in neurons treated with carbamazepine and oxcarbazepine. The toxic effect caused by carbamazepine was not mediated by N-methyl-D-aspartate (NMDA) or by alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionate (AMPA) receptors. Moreover, the antiepileptic drugs failed to protect hippocampal neurons from the toxicity caused by kainate, veratridine, or ischaemia-like conditions.

Human immune responses to Schistosoma mansoni vaccine candidate antigens

To determine the naturally occurring immunological responses to the Schistosoma mansoni antigens paramyosin, IrV-5, Sm-23 (MAP-3), and triose phosphate isomerase (MAP-4), a total of 119 subjects from an area of endemicity for schistosomiasis, including "resistant" subjects (n = 17) were evaluated. Specific immunoglobulin G1 (IgG1), IgG2, IgG3, IgG4, and IgA levels for each of the antigens and the cytokine profile in culture supernatants from antigen-stimulated peripheral blood mononuclear cells (PBMC) were determined. Although all the subjects had a high degree of contaminated water exposure, their infection levels were variable (0 to 1,128 eggs/g of stool). There were direct correlations between infection levels and levels of SWAP- and paramyosin-specific IgG1 and IgG4 (P < 0.05). However, an inverse correlation between infection levels and specific IgG2 to IrV-5 (P < 0.01) was observed. The evaluation of the cytokine profile (interleukin 5 [IL-5], IL-10, gamma interferon [IFN-gamma], and tumor necrosis factor alpha) in response to these antigens showed inverse correlations between the degree of infection and IFN-gamma levels in PBMC supernatants stimulated with paramyosin (P < 0.05) and IrV-5 (P < 0.01). Additionally, inverse correlations between the degree of infection and IL-5 levels in MAP-3- and MAP-4-stimulated PBMC supernatants (P < 0.01) were found. Logistic regression analysis was performed to adjust the results of cytokine profile by age. IL-5 production in MAP-3-stimulated PBMC supernatants was associated with lower infection levels (odds ratio = 11.2 [95% confidence interval, 2.7 to 45.8]).

[Clinical and laboratory characteristics of bacterial meningitis in children]

Data from the records of 528 children under 15 years old with diagnosis of acute bacterial meningitis, admitted at the Hospital Couto Maia between 1990 and 1992 were analyzed. Bacterial meningitis was more frequent in children under the age of 1 year (37.8%). The most common etiologic agent was H. influenzae (42.2%). The global lethality was 20.9%. Individual predictors of poor outcome were: absence of the "classic triad", CSF cell count under 1000/mm3, age under 2 years, presence of seizures, depressed sensorium, and S. pneumoniae as causal agent.

In vitro study on the interaction of Valeriana officinalis L. extracts and their amino acids on GABAA receptor in rat brain

This work studied in vitro the interaction of aqueous and hydroalcoholic extracts of Valeriana officinalis L. and compounds that are present in the extracts (amino acids and valerenic acid) with the GABAA (gamma-aminobutyric acid) receptor, using the [3H] muscimol binding technique to crude synaptic membranes from rat brain cortices. Both extracts displaced [3H]muscimol bound and this effect is probably due only to their amino acid content, specially GABA. This fact explains the in vitro effect of valerian extracts on GABAA receptor but not their sedative effect.