Tympanic membrane retraction tensa. Tympanic membrane retraction is fairly common and has been observed in one quarter of a population of British school children. Retraction of both eardrums is less common than having a retraction in just one ear. It is more common in children with cleft palate. Tympanic membrane retraction also occurs in adults. Attempts have been made to categorise the extent of tympanic membrane retraction though the validity of these classifications is limited. The majority of tympanic membrane retractions do not cause any symptoms. Some cause hearing loss by restricting sound-induced vibrations of the eardrum. Permanent conductive hearing loss can be
Membrane curvature several amphipathic alpha helices that allows it to partition between the hydrophobic core of the membrane and surrounding aqueous, hydrophilic environment. Another interesting characteristic of epsin and other proteins that bind to membranes is the fact that it shows high binding affinity for a fairly common membrane lipid, phosphatidylinositol 4,5-bisphosphate (PI-4,5-P2). Unlike other proteins that simply bend the membrane through sheer rigidity, epsin is a globular soluble protein and thus not rigid. The insertion of its helices into the membrane force the neighboring lipids of the leaflet that has been bound to expand laterally. This displacement of lipids on only