N omega-nitro-L-arginine methyl ester prevents apoptosis induced in the lateral geniculate nucleus by light deprivation in adult rabbit

Exposure of adult rabbits to darkness for 48 h produces bilateral DNA fragmentation in the lateral geniculate nucleus as revealed in brain sections by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labelling (TUNEL) technique, suggesting an apoptotic type of cell death. In agreement with the latter deduction, light microscopy assessment of the morphological characteristics showed marginalization and condensation of nuclear chromatin, typical features of apoptosis. These effects were abolished by systemic administration of N omega-nitro-L-arginine methyl ester, an inhibitor of nitric oxide (NO) synthesis, whereas the D isomer was ineffective. In conclusion, the present data demonstrate that light deprivation for 48 h produces apoptosis in the lateral geniculate nucleus of rabbit and suggest that NO might be involved

Brain involvement in glaucoma: Advanced neuroimaging for understanding and monitoring a new target for therapy

On the basis of a large body of experimental data the notion that glaucoma damages retinal ganglion cells and central areas of the visual system has been put forward. The mechanisms underlying glaucomatous involvement of the central areas are not known: the most likely hypothesis is that this event is the result of an anterograde transynaptic neurodegeneration triggered by ganglion cells' death. However, it is possible that in some cases it may be the consequence of a neurodegenerative disease of the central nervous system. In any event, novel mechanisms leading to cell demise might be implicated. The development of powerful neuroimaging techniques in conjunction with sophisticated analysis has recently provided compelling support to the involvement of central stations of the visual pathway in patients suffering of glaucoma. Diffusion Tensor-MRI allows the central damage associated with glaucoma to be assessed and therapeutic efficacy of novel neuroprotective interventions to be quantified. © 2012 Elsevier Ltd

Plasma waves in the sheath of the TSS-1R satellite

The current flow in the Tethered Satellite System (TSS) induces a strong excitation of electric and magnetic fluctuations in the potential sheath surrounding the subsatellite. The wave sensors of the experiment RETE (Research on Electrodynamic Tether Effects) have measured power spectra of electromagnetic fields from 180 Hz to 12 MHz, providing information on the physical processes taking place around highly charged bodies in the ionosphere and, in particular, the role of wave-particle interactions and anomalous collisionality. We report on the observations during three events of almost steady current flow at 50, 190 and 55 mA, taking place at positive satellite potentials of about 9, 200 and 2 V. The largest power spectral density occurs at frequencies between 2 and 4 kHz, close to the lower hybrid frequency, where electric field fluctuations up to 12 V/m have been observed. In this frequency band the fields are electrostatic and radially polarized, with a marked ram-wake signature