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Biomedical subjects

M J Capps

Publications and source records attributed to M J Capps.

11 recordsLinked to original sources
PubMed1977

Ototoxicity and the olivocochlear bundle.

Cochlear hair cell damage due to kanamycin sulfate was studied in chinchillas receiving 200 mg/kg kanamycin for nine days. The drug was given to a group of animals with lesions of the crossed olivocochlear bundle, a group that had received a sham operative procedure, and a group of normal animals. The animals were sacrificed 14 days after the last drug injection and the cochleae removed for examination by surface preparation. The lesioned animals showed markedly less hair cell loss than the control groups, and this was attributed to the fact that the loss of the efferent endings rendered these animals less susceptible to the ototoxic effects of kanamycin.

Animals↗
PubMed1977

Comparison of caloric and sinusoidal tests in the vestibulotoxic cat.

In order to evaluate the relative sensitivity of caloric and sinusoidal angular acceleration tests, thermal and rotational stimuli were administered to cats rendered vestibulotoxic with streptomycin sulfate. Three groups of six cats each, receiving daily subcutaneous injections of saline, 100 mg/kg streptomycin or 200 mg/kg streptomycin, were administered optokinetic, caloric and sinusoidal stimuli. Vestibular responses were evaluated by changes in the total slow phase displacement of the eyes and frequency of nystagmic beats. The results demonstrated that the saline treated animals had a decrease in response consistent with habituation; whereas, experimental animals showed a marked, rapid abolition of eye movement. The decrease in response was greater for the larger dose of streptomycin. Caloric or sinusoidal acceleration tests were equally sensitive in monitoring the degree of nystagmic depression. The data suggested that sinusoidal acceleration tests could be easily applied to the clinical vestibular assessment of ototoxicity.

Animals↗
PubMed1975

Visual stimulation: effects on vestibular habituation.

The influence of various forms of visual stimulation presented during the course of vestibular habituation to a caloric stimulus was studied. Eye movements which were either complementary or in opposition to the induced vestibular nystagmus were produced with an optokinetic drum. In addition, the effect of visual fixation during vestibular-response periods was studied. In all cases, the cats that received visual stimulation during the majority of the caloric trials habituated more slowly than did animals that received all the habituation trials in total darkness. These data conflict with previous reports of vestibular-visual interactions. Possible explanations for the discrepancy include species differences, distraction provided by the visual stimuli, and the transfer of learning from the dark to light conditions.

Animals↗
PubMedDate not supplied

Ototoxic interactions of ethacrynic acid and streptomycin.

Various aminoglycoside antibiotics and potent diuretics are known to depress cochlear and vestibular function. Several clinical and research studies suggest that the drugs administered together produce enhanced ototoxicity. The present series of experiments determines the depressive effects of ethacrynic acid and streptomycin, alone or in combination, upon the vestibular system of the cat. The changes in function, when quantified, indicate an addition, rather than a potentiation of toxicity, and suggest different sites of action.

Animals↗