From (pi,0) magnetic order to superconductivity with (pi,pi) magnetic resonance in Fe(1.02)Te(1-x)Se(x).

The iron chalcogenide Fe(1+y)(Te(1-x)Se(x)) is structurally the simplest of the Fe-based superconductors. Although the Fermi surface is similar to iron pnictides, the parent compound Fe(1+y)Te exhibits antiferromagnetic order with an in-plane magnetic wave vector (pi,0) (ref. 6). This contrasts the pnictide parent compounds where the magnetic order has an in-plane magnetic wave vector (pi,pi) that connects hole and electron parts of the Fermi surface. Despite these differences, both the pnictide and chalcogenide Fe superconductors exhibit a superconducting spin resonance around (pi,pi) (refs 9, 10, 11). A central question in this burgeoning field is therefore how (pi,pi) superconductivity can emerge from a (pi,0) magnetic instability. Here, we report that the magnetic soft mode evolving from the (pi,0)-type magnetic long-range order is associated with weak charge carrier localization. Bulk superconductivity occurs as magnetic correlations at (pi,0) are suppressed and the mode at (pi, pi) becomes dominant for x>0.29. Our results suggest a common magnetic origin for superconductivity in iron chalcogenide and pnictide superconductors.

Glycosaminoglycan levels and proteoglycan expression are altered in the hippocampus of patients with mesial temporal lobe epilepsy.

Extracellular matrix proteoglycans (PGs) and glycosaminoglycans (GAGs) play a crucial role in cell differentiation and synaptogenesis by modulating neurite outgrowth. The chondroitin sulfate (CS)-rich PG, the receptor protein tyrosine phosphatase zeta/beta (RPTP zeta/beta), has been related to neural morphogenesis and axon guidance. Hippocampal sclerosis is the most frequent pathologic finding in patients with intractable mesial temporal lobe epilepsy (MTLE), which is associated with neuron loss, reactive gliosis, and mossy fiber sprouting. In the present study, we investigated the concentration of CS, heparan sulfate (HS) and hyaluronic acid (HA) in the hippocampus and temporal neocortex as well as RPTP zeta/beta expression in the hippocampus of patients with MTLE. Compared to autopsy control tissue, epileptic hippocampi showed a significantly increased concentration of CS (224%; p=0.0109) and HA (146%; p=0.039). HS was instead similar to control values. No differences were found in the concentration of CS, HS, or HA in the temporal neocortex of epileptic patients when compared to control values. In contrast, RPTP zeta/beta immunoreactivity was induced in astrocytes of the inner molecular layer of the dentate gyrus of the sclerotic hippocampus. Because matrix compounds have been associated with tissue injury and repair, the present findings suggest that changes in PGs and GAGs might be related to damage-induced gliosis and neuronal reorganization in the hippocampus of MTLE patients.

[Comparison between CSF samples from AIDS and non AIDS patients with neurocryptococcosis]. / Estudo comparativo do LCR de pacientes com neurocriptococose sem AIDS e com AIDS.

Neurocryptococcosis was a rare nervous system infection. With the rising number of patients with AIDS it became a very frequent disease. This infection is supposed to infect patients with some kind of immunodeficiency and the CSF alterations often simulate tuberculous meningitis. The purpose of this research was to compare the CSF changes in AIDS and non-AIDS patients with meningoencephalitis caused by Cr. neoformans. There were analysed 41 CSF samples from non-AIDS patients with neurocryptococcosis and 23 CSF samples from AIDS patients with neurocryptococcosis. The results of this research allowed to conclude that the inflammatory changes in the CSF from AIDS patients showed a lower intensity compared to those non-AIDS patients. These results showed as well, that the CSF samples from non-AIDS patients always revealed some changes besides the yeast cells. In some samples of AIDS patients, however the unique change was the presence of the yeast. It was demonstrated also, that the presence of Cr. neoformans in CSF, not accompanied by any other change, may suggest that is a patient with AIDS. In non-AIDS patients CSF alterations often simulates tuberculous meningitis. However these alterations were rare in AIDS patients. The yeast cells were more numerous in CSF samples from AIDS patients than in those from non-AIDS patients.

Expression of GDNF transgene in astrocytes improves cognitive deficits in aged rats.

Glial cell line-derived neurotrophic factor (GDNF) was assayed for its neurotrophic effects against the neuronal atrophy that causes cognitive deficits in old age. Aged Fisher 344 rats with impairment in the Morris water maze received intrahippocampal injections at the dorsal CA1 area of either a lentiviral vector encoding human GDNF or the same vector encoding human green fluorescent protein as a control. Recombinant lentiviral vectors constructed with human cytomegalovirus promotor and pseudotyped with lyssavirus Mokola glycoprotein specifically transduced the astrocytes in vivo. Astrocyte-secreted GDNF enhanced neuron function as shown by local increases in synthesis of the neurotransmitters acetylcholine, dopamine and serotonin. This neurotrophic effect led to cognitive improvement of the rats as early as 2 weeks after gene transduction. Spatial learning and memory testing showed a significant gain in cognitive abilities due to GDNF exposure, whereas control-transduced rats kept their performance at the chance level. These results confirm the broad spectrum of the neurotrophic action of GDNF and open new gene therapy possibilities for reducing age-related neurodegeneration.

Astrocytes aged in vitro show a decreased neuroprotective capacity.

Alterations in astrocyte function that may affect neuronal viability occur with brain aging. In this study, we evaluate the neuroprotective capacity of astrocytes in an experimental model of in vitro aging. Changes in oxidative stress, glutamate uptake and protein expression were evaluated in rat cortical astrocytes cultured for 10 and 90 days in vitro (DIV). Levels of glial fibrillary acidic protein and S100beta increased at 90 days when cells were positive for the senescence beta-galactosidase marker. In long-term astrocyte cultures, the generation of reactive oxygen species was enhanced and mitochondrial activity decreased. Simultaneously, there was an increase in proteins that stained positively for nitrotyrosine. The expression of Cu/Zn-superoxide dismutase (SOD-1) and haeme oxygenase-1 (HO-1) proteins and inducible nitric oxide synthase (iNOS) increased in aged astrocytes. Glutamate uptake in 90-DIV astrocytes was higher than in 10 DIV ones, and was more vulnerable to inhibition by H2O2 exposure. Enhanced glutamate uptake was probably because of up-regulation of the glutamate/aspartate transporter protein. Aged astrocytes had a reduced ability to maintain neuronal survival. These findings indicate that astrocytes may partially loose their neuroprotective ability during aging. The results also suggest that aged astrocytes may contribute to exacerbating neuronal injury in age-related neurodegenerative processes.

Avaliação do desempenho dos testes functional reach e lateral reach em amostra populacional brasileira / Assessment of performance in the functional reach and lateral reach tests in a Brazilian population sample

OBJETIVOS: O objetivo deste estudo foi avaliar os padrões de desempenho dos testes Functional Reach e Lateral Reach em uma amostra de indivíduos saudáveis de 20 a 87 anos e verificar a influência do gênero, idade, estatura do indivíduo, peso corporal, comprimentos do braço e do pé. MÉTODO: foi realizado um estudo observacional transversal com 98 pessoas de ambos os gêneros, que residiam na capital e interior de São Paulo. Os voluntários tiveram suas medidas descritivas registradas e posteriormente foram submetidos aos testes Functional Reach e Lateral Reach. RESULTADOS: Para o FR, todas as variáveis tiveram influência, exceto o comprimento do braço (p=0,057), o peso corporal (p=0,746) e a base de suporte usada no momento da avaliação (p=0,384). As variáveis que exerceram maior influência foram o gênero (p=0,001), a idade (p<0,001) e a estatura (p=0,004) do indivíduo. Esta análise mostrou que as mulheres têm um alcance funcional anterior e lateral menor que os homens. Houve uma correlação positiva substancial (r=0,696) entre os valores encontrados no LR à esquerda e à direita. Já o FR teve uma correlação positiva moderada de 0,405 com o LR à esquerda e de 0,614 à direita, sendo então, considerada positiva substancial. Para o LR, as variáveis estatura, peso, comprimentos do braço e do pé não foram significantes na sua determinação. CONCLUSÕES: O padrão de medidas dos testes FR e LR utilizados pela literatura internacional não podem ser os mesmos para os brasileiros. As principais medidas que influenciam os testes são a idade, o gênero e a estatura.

OBJECTIVE: To assess the performance in the functional reach test (FR) and lateral reach test (LR) among a sample of healthy individuals aged 20 to 87 years and to verify the influence of gender, age, height, body weight, arm length and foot length. METHOD: A cross-sectional observational study was conducted on 98 people of both genders living in the city of São Paulo and other places in the State of São Paulo. The volunteers were measured and then underwent FR and LR. RESULTS: All the variables had an influence on FR, except arm length (p=0.057), body weight (p=0.746) and the support base used at the time of assessment (p=0.384). The variables exerting greatest influence were the individual's gender (p=0.001), age (p<0.001) and height (p=0.004). This analysis showed that women had less anterior and lateral functional reach than men. There was a substantial positive correlation (r=0.696) between the left and right LR findings. FR had a moderate positive correlation of 0.405 with the left LR and a substantial positive correlation of 0.614 with the right LR. For LR, the height, weight, foot length and arm length variables were not significant determinants. CONCLUSION: The measurement patterns for FR and LR that are used in the international literature may not be the same for Brazilians. The main measurements that influence the tests are age, gender and height.