Biomedical subjects
Publications and source records attributed to J Holmquist.
A simple technique for the measuring of sound intensities produced by drilling in ear surgery is presented. In 6 patients the sound level from drilling in the mastoid exceeded 100 dBA. The drilling device should be so designed as to avoid acoustic trauma. Furthermore, a surgical technique should be selected, which minimizes the noise levels and duration of exposure as far as is possible.
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.
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.
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Hearing loss and vertigo experienced as a result of environmental pressure change has been the subject of many superficial inquiries. The mechanism of these conditions remains obscure. In human volunteers and a rhesus monkey, the effects of intratympanic as well as ear canal pressure changes on the endolymphatic system were measured using electronystagmography (ENG). For the monkey histological evaluation of the pressure effects on auditory structures was performed. We were unable to cause any ENG effects on the monkey neither did we produce intracochlear pathology. The data obtained in humans using a similar approach are presented and explanations for the mechanism related to hearing loss and vertigo in barotrauma are discussed.
Patients on digitalis medication at the time of diagnosis of breast cancer seem to develop tumors that have a lower growth potential than do patients not on such medication. These tumors are photometrically characterized by small nuclei with lower DNA-RNA content and less variation in morphometric characteristics.
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