AΒ-DERIVED DIFFUSIBLE LIGANDS (ADDLS) INHIBIT CHOLINE ACETYLTRANSFERASE ACTIVITY IN CULTURED NEURONS

isturbances of the cholinergic network are implicated in the development of several pathologies of the CNS, such as Alzheimer’s disease (AD) (reviewed in: J Pharmacol Exp Ther. 2003 Sep; 306(3):821-7). AD is an alarmingly prevalent form of dementia, that is neuropathologicaly characterized by extracellular accumulation of fibrillar deposits in senile plaques, intraneuronal fibrillary tangles consisting of abnormally hyperphosphorylated tau protein, oxidative damage, synaptic loss and neuronal degeneration. The amyloid- peptide (A), is the main constituent of amyloid deposits in AD, and is currently regarded as the major culprit of the disease. Data from both genetic screening of patients and in vitro experiments support this view, although the exact mechanism by which Aexerts its effects is still quite unclear (Physiol Rev. 2010 Apr;90(2):465-94). In the current study, we used cultured cholinergic neurons, obtained from the retinas of 8-9 days old embryonic chicks and kept in vitro for 4-6 days, and evaluated the effects of chronic incubation with ADDLs on ChAT activity, by means of a classic radiometric assay (J. Neurochem. 24,407-409). Results show that cultures exposed to ADDLs (500nM, for 17hours) lose approximately 50% of their normal ChAT activity and that this effect can be fully blocked by the glutamatergic antagonists MK-801 and DNKeywords: Alzheimer Disease. Acetylcholine. Choline Acetyltransferase. Oxidative Stress. Neurological disturbes

Desempenho do membro não-acometido em pacientes com reconstrução do ligamento cruzado anterior Performance of uninjured lower limb after anterior cruciate ligament reconstruction

Défices sensoriais persistentes após a reconstrução do ligamento cruzado anterior (LCA) podem causar alterações como fraqueza muscular e comprometimento do equilíbrio e do desempenho funcional. Diversos estudos discutem se essas alterações também estão presentes no membro inferior não-acometido e se esse membro pode ser utilizado como referência nas avaliações desses pacientes. O objetivo do presente estudo foi comparar o torque extensor e flexor do joelho, o equilíbrio unipodal e o desempenho funcional sobre o membro não-acometido de pacientes submetidos à reconstrução do LCA, com membros inferiores de sujeitos saudáveis. Participaram do estudo 23 indivíduos submetidos à reconstrução do LCA e 22 sujeitos saudáveis, que foram avaliados quanto ao torque extensor e flexor do joelho durante contração isocinética concêntrica a 60 graus/s no dinamômetro isocinético, à velocidade média de oscilação do centro de pressão em apoio unipodal no baropodômetro, e submetidos a dois testes de salto para avaliar o desempenho funcional. Os resultados não revelaram diferenças entre o membro não-acometido e os membros inferiores do grupo controle em todas as variáveis estudadas (p>0,05). Esses resultados sugerem que o membro não-acometido de pacientes submetidos à reconstrução do LCA pode ser utilizado como referência nos estudos de avaliação desses pacientes.<br>Persistent sensorial deficits after anterior cruciate ligament (ACL) reconstruction might lead to muscle weakness, balance and functional performance disorders. Several studies inquire whether these alterations also appear in the uninjured limb and whether the latter could be used as reference for patient assessment. The aim of the present study was to compare knee extensor and flexor torque, balance and functional performance of non-injured lower limb, after contralateral ACL reconstruction, with lower limbs of healthy subjects. Twenty-three male patients who had had ACL reconstruction, and 22 control subjects were assessed as to knee flexor and extensor torque during concentric isokinetic contraction at 60o/s with an isokinetic dynamometer, mean speed of centre of pressure swing during single-limb stance, and submitted to two hop tests to assess functional performance. Results showed no significant differences between uninjured side and healthy subjects lower limbs at all assessed variables (p>0.05). These findings suggest that the uninjured limb may be safely used as reference in studies to assess post-ACL patients