The chronic wounds problem affect millions of people worldwide, becoming a great challenge to the healthcare systems. The normal healing consists of three phases: inflammation, proliferation and remodelation. Problems in any of these can lead to chronic wounds. The disease diabetes, for example, induces systemic production of free radicals, and also the antioxidant capacity decreases, which induces severe tissue damage decreasing the healing process. The diabetic disease state can also disrupt the balance between promoting vessel growth and proliferation and promoting vessel maturation and quiescence. The idea was to develop an antioxidant extract loaded matrix and evaluate the in vitro released antioxidant activity by the comparison between two spectrometric techniques to obtain a model dressing that could provide the biological advantages of both starting materials, increased vascularization for the natural latex matrix, and antioxidant activity for the S. marginata extract. According to FTIR analysis, matrix and extract did not interact chemically. Furthermore, at 67 h, up to 27% of all incorporated extract was released. The SEM images showed a portion of extract on the matrix surface, being responsible for the burst release. On the other hand, another portion remains within the matrix, being responsible for the slower release. The extract antioxidant activity was maintained even after its incorporation into the matrix. The comparison between the results obtained showed that the fact that the DPPH EPR spectrum has a relatively simple signal due only to the free radical is an advantage in relation to the optical spectroscopy. Based on the obtained results, it was possible to conclude that matrix is able to load the extract and maintain its antioxidant activity. However, in vivo and clinical assays are needed in the future to prove the clinical efficiency of the developed dressing.
The dorsal cochlear nucleus (DCN) in the auditory brainstem integrates auditory and somatosensory information. Mature DCN fusiform neurons fall into two qualitatively distinct types: quiet, with no spontaneous regular action potential firing, or active, with regular spontaneous action potential firing. However, how these firing states and other electrophysiological properties of fusiform neurons develop during early post-natal days to adulthood is not known. Thus, we recorded fusiform neurons from mice from P4 to P21 and analyzed their electrophysiological properties. In the pre-hearing phase (P4-P13), we found that most fusiform neurons are quiet, with active neurons emerging after hearing onset at P14. Subthreshold properties underwent significant changes before hearing onset, whereas changes to the action potential waveform occurred mainly after P14, with the depolarization and repolarization phases becoming markedly faster and half-width significantly decreased. The activity threshold in post-hearing neurons was more negative than in pre-hearing cells. Persistent sodium current (INaP) was increased after P14, coinciding with the emergence of spontaneous firing. Thus, we suggest that post-hearing expression of INaP leads to hyperpolarization of the activity threshold and the active state of the fusiform neuron. At the same time, other changes refine the passive membrane properties and increase the speed of action potential firing of fusiform neurons.
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