Effect of Streptomycin on the Otoconial Layer of the Guinea Pig

Takumida, Masaya; Zhang, De Ming; Yajin, Koji; Harada, Yasuo

doi:10.1159/000276950

Cited by 12 publications

(8 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By contrast, when degeneration of otoconia or formation of giant otoconia was induced by application of streptomycin, an apparently normal complement of otoconia was restored at 8–10 weeks following cessation of drug treatment 24,25…”

Section: Maintenance/renewal Of Mature Otoconiamentioning

confidence: 99%

Development and Maintenance of Otoconia

Thalmann

Ignatova

Kachar

et al. 2001

Annals of the New York Academy of Sciences

111

View full text Add to dashboard Cite

The first part of this review deals with recent advances in the understanding of biochemical mechanisms of otoconial morphogenesis. Most important in this regard is the molecular characterization of otoconin 90, the principal matrix protein of mammalian calcitic otoconia, which was found to be a homologue of the phospholytic enzyme PLA2. The unique and unexpected expression pattern of this protein required radical rethinking of traditional concepts. The new data, when integrated with existing information, provide a rational basis for an explanation of the mechanisms leading to crystal nucleation and growth. Based on this information, a hypothetical model is presented that posits interaction of otoconin 90 with microvesicles derived from the supporting cells as a key event in the formation of otoconia. The second part of the review is directed at the controversial subject of maintenance of mature otoconia and systematically analyzes the available indirect information on this topic. A synthesis of these theoretical considerations is viewed in relation to the pathogenesis of the important otoneurologic entities of BPPN and senile otoconial degeneration. The last part of the review deals with several animal models that promise to help elucidate normal and abnormal mechanisms of otoconial morphogenesis, including mineral deficiencies, mutations with selective otoconial agenesis, as well as targeted disruption of essential genes.

show abstract

Section: Maintenance/renewal Of Mature Otoconiamentioning

confidence: 99%

Development and Maintenance of Otoconia

Thalmann

Ignatova

Kachar

et al. 2001

Annals of the New York Academy of Sciences

111

View full text Add to dashboard Cite

show abstract

“…Earlier investigations in animals showed comparable structural changes of otoconia owing to systemic streptomycin administration [28], [29], [30], [31]. Aminoglycosides are able to enter the vestibular endolymph after systemic administration, leading to morphological changes of otoconia in the saccule and the utricle.…”

Section: Discussionmentioning

confidence: 89%

Principles of Calcite Dissolution in Human and Artificial Otoconia

et al. 2014

View full text Add to dashboard Cite

Human otoconia provide mechanical stimuli to deflect hair cells of the vestibular sensory epithelium for purposes of detecting linear acceleration and head tilts. During lifetime, the volume and number of otoconia are gradually reduced. In a process of degeneration morphological changes occur. Structural changes in human otoconia are assumed to cause vertigo and balance disorders such as benign paroxysmal positional vertigo (BPPV). The aim of this study was to investigate the main principles of morphological changes in human otoconia in dissolution experiments by exposure to hydrochloric acid, EDTA, demineralized water and completely purified water respectively. For comparison reasons artificial (biomimetic) otoconia (calcite gelatin nanocomposits) and natural calcite were used. Morphological changes were detected in time steps by the use of environmental scanning electron microscopy (ESEM). Under in vitro conditions three main dissolution mechanisms were identified as causing characteristic morphological changes of the specimen under consideration: pH drops in the acidic range, complex formation with calcium ions and changes of ion concentrations in the vicinity of otoconia. Shifts in pH cause a more uniform reduction of otoconia size (isotropic dissolution) whereas complexation reactions and changes of the ionic concentrations within the surrounding medium bring about preferred attacks at specific areas (anisotropic dissolution) of human and artificial otoconia. Owing to successive reduction of material, all the dissolution mechanisms finally produce fragments and remnants of otoconia. It can be assumed that the organic component of otoconia is not significantly attacked under the given conditions. Artificial otoconia serve as a suitable model system mimicking chemical attacks on biogenic specimens. The underlying principles of calcite dissolution under in vitro conditions may play a role in otoconia degeneration processes such as BPPV.

show abstract

“…difficile is a common, fecal-borne, anaerobic, grampositive, commensal organism whose large, subterminal spores persist in the environment. Otoconial (inner ear cell) loss in the striola region of both utricle and saccule occurred in adult, mixed-sex guinea pigs following seven intraperitoneal injections of streptomycin at 250 mg/kg per injection (Takumida et al, 1997). Toxin B is more cytotoxic but requires toxin A (known also as an enterotoxin) to access mucosal cells.…”

Section: Antibiotic-associated Typhlocolitismentioning

confidence: 99%