Evaluation of light-emitting diodes (LED) effect on skin biology (in vitro study).

BACKGROUND: Interest in anti-aging approaches has grown significantly in recent years. The most popular are the non invasive methods to decrease the signs of aging. One such method is LED-based therapy. METHODS: This study investigated the potential of two different wavelengths, 590 nm and 630 nm, combined or not, in the photobiomodulation of proteins involved in the slowdown of the skin aging. RESULTS: These in vitro results on cell viability, cell shape, and mitochondrial function support and build on previous studies suggested that LED treatment is safe. Regarding its biological functions, our data indicated that the combination of two different wavelengths acted in synergy to enhance the impact of each irradiation alone. Combined, the LED wavelengths could improve in vitro the cell shape, the cell proliferation, and the level of major proteins involved in the healing process. CONCLUSION: These benefits may lead to reinforcement of the skin organization and structure. This hypothesis will be checked in future clinical studies.

[Prognostic value of electroneuronography and trigemino-facial reflex in Bell's palsy]. / Valeur pronostique de l'électroneuronographie et du réflexe trigémino-facial dans la paralysie faciale a frigore.

56 patients with Bell's palsy were tested with electroneuronography (ENoG and Blink reflex (BR) within the 5th and 15th day of onset of facial paralysis. The recovery at the end of evolution was evaluated with the study of facial function. This retrospective study showed that ENoG is able to predict with a very low risk of error a good prognosis when more than 10 percent (strictly, of fibers (non degenerated and blocked) are active. On the other hand only persistence or early recovery of BR can assure a good prognosis whereas the absence do not permit to conclude.

Electrophysiological evidence for the presence of NMDA receptors in the guinea pig cochlea.

An excitatory amino acid, possibly L-glutamate, which probably acts as a neurotransmitter at the inner hair cell-afferent fiber synapses in the cochlea. In the present study, we have used an electrophysiological approach to investigate at this level the presence of a major type of excitatory amino acid receptor, namely the glutamatergic receptor for which N-methyl-D-aspartate is a selective agonist. Our results show that, when N-methyl-D-aspartate and the antagonist 2-amino-5-phosphonovalerate are perfused through the perilymphatic scalae, they induced, by different mechanisms, a significant reduction of the amplitude of the compound action potential and an increase of the N1 latency, both predominant at high intensity tone burst stimulations. No significant difference was found in the presence or absence of Mg2+ in the artificial perilymph used as a vehicle. A further slight N-methyl-D-aspartate-induced decrease of the amplitude of the compound action potential, although non significant, was observed when the Mg2(+)-free perilymph contained 100 or 1000 microM glycine. In all the experimental conditions, no effect was observed on the cochlear microphonic potential. This observation is consistent with an action of N-methyl-D-aspartate and 2-amino-5-phosphonovalerate at receptors located on the auditory nerve dendrites contacting the inner hair cells. In conclusion, our results suggest the presence of N-methyl-D-aspartate receptors in the cochlea.