Effects of cold stress on early and late stimulus gating.

The P50 component of the event-related potential (ERP) mainly reflects early pre-attentional processing. Along with P50, the N100 component and mismatch negativity (MMN) were postulated to represent a complex multistage and multi-component gating system. If some variable threshold or gating is exceeded by the MMN signal, the MMN is often followed by a relatively sharp fronto-central positive wave, the P3a component, which reflects an attentional switch to an environmental change.

Lipid peroxidation and osmotic fragility of red blood cells in sleep-apnea patients.

Background: Obstructive sleep apnea (OSA) refers to the occurrence of episodes of complete or partial pharyngeal obstruction with oxyhemoglobin desaturation during sleep. These hypoxia/reoxygenation episodes may cause generation of reactive oxygen species. Reactive oxygen species are toxic to biomembranes and may lead to the peroxidation of lipids.