A map of cochlear perilymph protein based on high-resolution two-dimensional electrophoresis.

For systematic characterization of cochlear perilymphatic (PL) fluid proteins and to compare the complex protein mixtures of PL fluid, cerebrospinal fluid (CSF) and blood plasma, we subjected eight postmortem PL fluid samples to two-dimensional (2D) electrophoresis. To avoid contamination of perilymph by blood and blood plasma, the samples were taken immediately after death and analyzed by keeping to certain selection criteria. When compared with CSF, PL fluid in the scala vestibule was found to have an albumin content of approximately 1-2g/l, or 10 times the level of CSF albumin.

Protein distribution in the human perilymph. A comparative study between perilymph (post mortem), CSF and blood serum.

The large differences in the protein content of perilymph and serum as well as the perilymph volume limit of 10-15 microliter cause serious problems when collecting samples of uncontaminated perilymph in order to analyse its protein composition. In 8 out of 24 extremely carefully taken samples of perilymph removed during autopsy, we were able, by keeping to certain selection criteria, to carry out electrophoretic analyses which were suitable for reproduction and comparison. Comparison of human perilymph, CSF and serum, using SDS-Page and Western blotting, gave the expected agreement which had been suggested by tests on guinea pigs.

[Detection of beta 2-transferrin with agarose gel electrophoresis, immunofixation and silver staining in cerebrospinal fluid, secretions and other body fluids].

A method is described for the detection of beta 2-transferrin (asialotransferrin) in 1 microliter cerebrospinal fluid. Owing to its low content of sialic acid, beta 2-transferrin migrates more slowly than the main transferrin component (beta 1-transferrin) in electrophoresis. The high sensitivity and specificity of the test depend on immunofixation of the electrophoretically separated transferrin in the agarose gel, and on the visualization of the immune complex by staining with alkaline silver nitrate solution.