[Electron microscopy studies of the collagen fiber structure of the human tympanic membrane in an adhesive process]. / Elektronenoptische Untersuchungen zur Kollagenfaserstruktur des menschlichen Trommelfells beim Adhäsivprozess.

In an EM study, the collagen fiber arrangement of the lamina propria in adhesive otitis media was investigated. Nine biopsies of the tympanic membrane were taken intraoperatively, and compared with two normal ones. The physiological specimens showed a regular arrangement of collagen fibrils and fibers, the typical network of the lamina propria. This confirmed results reported previously. In all adhesive otitis media samples the regular structure of the fiber arrangement was disturbed. Degenerative processes were to be found in the form of hyaline changes, with the network character of the fibers no longer in evidence. In one specimen a mass of microfibrils was observed, which was possibly a sign of reparative processes. The pathohistological findings in adhesive otitis media may be due to mechanical stresses (tubal function). Aside from that, they may also be caused by the biochemical influence of specific collagenases, which have been found by several authors in secretory otitis was well as in cholesteatoma.

The influence of social rank on the susceptibility of rats to Mycoplasma arthritidis.

Social ranks (A, O, rest) of adult male inbred rats housed in groups of four per cage were determined by repeated observations of their ejaculatory patterns under competitive conditions. Once ranked, they were intravenously infected. Fifteen clinical, hematological, and serological characters were continuously observed during 110 days. Body weight reduction, arthritis score, and specific IgG antibody titers were chosen as guideline characteristics and compared between different genotypes and social rank classes. Genotypic differences account for 60-80% of the individual differences and social rank differences account for 0-40% of the individual differences within isogenic animals. Social rank affects the individual genotypes in an opposite way. Rank A males are less susceptible in genotype DA but showed increased susceptibility in genotypes AS. In genotype LEW, influence of social rank on susceptibility to Mycoplasma arthritidis could not be verified. Specific IgG antibody titers are lower in ranks showing a higher degree of susceptibility.