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. However, a closer examination of individual proteins pointed to some relatively large differences in quantity and quality.

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. Due to the small volume of the sample obtained, it was not possible to concentrate the PL fluid. As a result, protein spots in the 2D-gel could only be detected with a highly sensitive silver stain. Visual inspection of the resulting 2D-electrophoretograms showed that most of the "CSF-specific" protein clusters were present in the PL fluid pattern.

Zusammenfassung: Untersuchungen an Zystenflüssigkeiten und Seren von Patienten mit zystisch degenerierten euthyreoten Strumen ergaben für die meisten untersuchten chemischen Substanzen signifikante Konzentrationsunterschiede zwischen Zystenflüssigkeit und Serum. In der gelben Zystenflüssigkeit finden sich durchwegs niedrigere, in brauner Zystenflüssigkeit meist höhere Konzentrationen als in den zugehörigen Seren. Diffusions-und Resorptionsvorgänge, autolytische und metabolische Prozesse und für Schilddrüsenhormone auch eine aktive Inkretion durch wandbildendes Schilddrüsengewebe sind Ursache der Konzentrationsunterschiede. Biochemical data in the fluids of cystic degenerated euthyroid goitersSummary: Examinations of sera and cyst fluids in patients with cystic degenerated euthyroid goiters showed significant differences between the values of the cyst fluids and sera for almost all of the chemical substances. In the brown cyst fluids there are mostly higher values compared with the appropriate sera. Autolysis, diffusion and resorption, metabolic changes and, in the case of thyroid hormones, active incretion by wall-forming thyroid tissue, are the reasons for these differences in the concentrations. Einfuhrung