Jan Jarlstedt

Collagenase Activity in Middle Ear Effusions

Collagenolytic enzyme activity has been demonstrated in middle ear effusions from patients suffering from otitis media with effusion. Collagenase activity was characterized using different biochemical techniques. Various chemical and physical parameters were titrated for optimal enzyme activity. Bivalent cations activated the enzyme with Ca2+ as the most potent activator. Chelators such as EDTA reduced the enzyme at low concentrations. The enzyme was found to have a higher specific activity in mucoid effusions than in serous and had characteristics similar to granulocyte derived collagenase from human leukocytes. Possible relationships between the presence of collagenase activity and tissue destruction in the middle ear after otitis media with effusion are discussed. The collagenase activity showed wide ranges within different categories of middle ear effusions.

Identification of Middle Ear Disease

Since impedance measurements were introduced as a mean of identifying ears affected by middle ear disease, efforts have been concentrated on the identifying of ears in which effusion is present. The shape of the tympanogram has been analysed and it has been proposed that ears producing a shallow tympanometric pattern are more likely to contain fluid in the middle ear, than are ears having a tympanogram with a large peak. In this communication and great individual variation of tympanograms is shown and it is suggested that two categories of tympanogram should be considered, namely 1) flat tympanogram, and 2) tympanograms in which the middle ear pressure can be determined.

Effect of cerebellectomy upon the cytochemistry of neurons in the lateral vestibular nucleus. III. Cytochemical response to unilateral vestibular stimulation after midline section of the brain stem

Abstract Total cell mass, RNA content and succinoxidase activity were determined bilaterally in isolated giant nerve cells from the lateral vestibular nucleus (n. Deiters) of rabbits subjected to cerebellectomy and midline division of the brain stem. The cytochemical response to unilateral irrigation with warm or cold water was measured in these animals. The midline division of the brain stem notably diminished this response compared with that observed in solely cerebellectomized animals. However, the persistence of some contralateral effects, particularly on the succinoxidase activity of the giant nerve cellsm indicates the importance to commissural fibers between the vestibular nuclei, outside the level of the brain stem.

In Vivo Studies on Amino Acid Transmitters in the Central Auditory System of the Guinea Pig

The extracellular concentrations of endogenous amino acids were measured in vivo in the guinea pig cochlear nucleus during sound stimulation. The purpose was to explore whether certain amino acids might be employed as neurotransmitters by the auditory nerve. A dialysis sampling probe was used to collect a dialysate of the cochlear nucleus. The amino acids were determined fluorometrically after precolumn derivation and high-performance liquid chromatography separation. A short pulse of p-chloromercuryphenylsulfonate (p-CMS) was used to reduce the reuptake of amino acids. The concentration of glutamic and aspartic acid increased twofold to threefold during sound stimulation, while gamma-aminobutyric acid was unaffected. The results support a role for glutamic and/or aspartic acids as neurotransmitters in the auditory nerve.

Biochemical characterization of collagenase activity from middle ear effusions.

Collagenolytic enzyme activity has been demonstrated in middle ear effusions from patients suffering from otitis media with effusion. Collagenase activity was characterized using different biochemical techniques. The enzyme was found to have a higher specific activity in mucoid effusions and had characteristics similar to granulocyte derived collagenase from human leucocytes.