Electrophoretic Separation and Identification of Perilymph Proteins in Cases of Acoustic Neuroma

Abstract

Previous studies of perilymph proteins have emphasised the difficulty of obtaining samples free of blood or serum proteins. The present investigation has established a method of polyacrylamide gel electrophoresis, which enables contaminated specimens to be readily identified and therefore discarded. Analysis of uncontaminated samples has confirmed the presence of an elevated perilymph protein in cases of acoustic neurinomata. Perilymph proteins have been separated and identified and although no characteristic pattern of proteins associated with acoustic neurinomata has emerged, further work should be undertaken to establish the site of origin of perilymph proteins and the pattern of abnormalities to be expected in pathological processes.

Predictors of Volumetric Growth and Auditory Deterioration in Vestibular Schwannomas Followed in a Wait and Scan Policy

“…Previous studies indicate that the presence of a VS causes significant biochemical alterations of the inner ear fluids (31Y33), with an increased perilymphatic protein content (33,34). It has been suggested that these alterations are related to vascular impairment caused by mechanical obstruction by the VS (30,31). This hypothesis may be supported by Lapsiwala et al (35), who found a significant correlation between IAC pressure and preoperative hearing level.…”

Increased Cochlear Fluid-Attenuated Inversion Recovery Signal in Patients with Vestibular Schwannoma

“…2,7,8 These studies have not found a relationship between perilymph protein levels and the degree of hearing loss or abnormalities of eighth nerve action potentials. Given the likelihood of contamination of perilymph with blood and other fluids during the surgical procedure and the small quantities of the fluid obtained during the procedure, these rela- tionships have not been thoroughly investigated.…”

“…4 The pathogenesis of increased inner ear perilymph protein has been a matter of considerable investigation in the past. 4,[6][7][8][9] However, to date, no one agrees on a satisfactory explanation for this phenomenon. Furthermore, it has also remained unclear if protein levels in perilymph correlate with the degree of hearing loss and abnormal eighth nerve action potentials in patients with vestibular schwannoma.…”

“…The most plausible explanations suggested are the following: 1) blockage of neuroaxonal transport of proteins by tumor-related compression of the cochlear nerve, 2) cochlear membrane damage by arterial stasis resulting in increased permeability, and 3) cell-mediated immune reaction in the inner ear to antigenic properties of vestibular schwannomas. 4,[6][7][8][9][10] Although higher perilymph protein levels have been reported with larger vestibular schwannomas, this effect has not been related to cochlear aqueduct obstruction. 4 Moreover, cerebellopontine angle meningiomas, which can easily obstruct the cochlear aqueduct by virtue of their location, usually have less elevation of perilymph protein than vestibular schwannomas.…”

Clinical Significance of an Increased Cochlear 3D Fluid-Attenuated Inversion Recovery Signal Intensity on an MR Imaging Examination in Patients with Acoustic Neuroma

“…7,[10][11][12] The most plausible mechanisms include blockage of the neuroaxonal transport of proteins caused by compression of the vestibulocochlear nerve, cochlear membrane damage caused by arterial stasis and a consequent increased permeability, and a cell-mediated immune reaction to the inner ear caused by the antigenic properties of AN. [7][8][9][10][11][12]23 Among the 3 hypotheses, protein blockage from compression of the corresponding nerve is considered to be the dominant mechanism, with the others being minor in their contribution. Given that the cochlear signal reflecting the protein concentration correlates well with the degree of hearing loss represented by PTA in AN IAC but not in AN CPA , we could hypothesize that the degree of nerve compression is a major contribution to increasing the protein concentration while the tumor is confined to the internal auditory canal.…”