Effects of Otic Drops on the Chinchilla Tympanic Membrane

Masaki, Masami

doi:10.1097/00006454-198907000-00027

Cited by 10 publications

(25 citation statements)

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“…Additional facilitating agents have been considered, such as prostaglandins and leukotrienes (40). Propylene glycol has been shown to cause in ammatory reactions in the tympanic membrane (47). This raises questions as to the effect of propylene (a common component of otic drops) on the permeability of the round window membrane.…”

Section: Facilitating Agentsmentioning

confidence: 99%

Clinical Aspects of Round Window Membrane Permeability Under Normal and Pathological Conditions

Goycoolea

2001

Acta Oto-Laryngologica

197

168

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Current research and an overall review of 25 years of round window membrane studies are presented. The approach, rationale and concepts that have evolved from these studies are described. Ultrastructural studies of the round window membrane of humans, monkeys, felines and rodents have disclosed three basic layers: an outer epithelium, a middle core of connective tissue and an inner epithelium. Interspecies variations are mainly in terms of thickness, being thinnest in rodents and thickest in humans. Morphologic evidence suggests that the layers of the round window participate in resorption and secretion of substances to and from the inner ear, and that the membrane could play a role in the defense system of the ear. Different substances, including antibiotics and tracers, when placed in the middle ear side traverse the membrane. Tracers placed in perilymph become incorporated into the membrane by the inner epithelial cells. Permeability is selective and factors affecting permeability include size, concentration, electrical charge, thickness of the membrane and tacilitating agents. Passage of substances through the membrane is by different pathways, the nature of which is seemingly decided at the outer epithelium of the membrane. Round window membrane studies have provided increased knowledge of the anatomy and function of this structure, as well as new insights into pathology and pathogenesis. The concepts that have evolved from these studies are potentially useful for understanding middle and inner ear interactions, and for eventual drug delivery (based on permeability) to the inner ear.

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Section: Facilitating Agentsmentioning

confidence: 99%

Clinical Aspects of Round Window Membrane Permeability Under Normal and Pathological Conditions

Goycoolea

2001

Acta Oto-Laryngologica

197

168

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“…13 Theses description have also been published by other authors. 3,14 The tympanic membrane alterations we found in 40 ears (control and experiment groups) included visible retro-tympanic cholesteatomas in four ears, of which two presented retraction, and tympanic membrane perforation in seven ears. We were able, therefore, to observe cholesteatoma formation in retracted, intact and perforated tympanic membranes; perforation might be secondary to necrosis, itself resulting from inflammation caused by the middle ear mucosa-irritating agent.…”

Section: Discussionmentioning

confidence: 86%

“…3 Cholesteatoma formation due to PG appears to be dose dependent. 4,12 In our study we used PG (100%) to induce cholesteatoma formation in the middle ears of as many animals as possible.…”

Section: Discussionmentioning

confidence: 99%

“…4 A single application of PG (50%) on the bulla of chinchillas was enough to show evidence of cholesteatoma formation on the third week. 3 The time, therefore, between applying the mucosal irritant and sacrificing the animal is important for cholesteatoma formation; from the third week onwards epithelial migration and a typical cholesteatoma have been formed, in most papers. The moment for analyzing the specimens histologically varied according to different authors and cholesteatoma-inducing techniques; we chose six weeks, similar to some other authors, as we believe that this period is sufficient for a cholesteatoma to form.…”

Section: Discussionmentioning

confidence: 99%

“…2 Propylene glycol (PG) has been shown to cause epithelial migration and cholesteatomatous chronic otitis media in NorthAmerican chinchillas, in which optic drops (Cortisporin) containing PG (10%) was used. 3 Increasing the dose of PG in topical preparations injected transtympanically yields cholesteatomas 4,5 in a progressively higher percentage of rats, reaching 100% at a concentration of 90%. After producing a cholesteatoma in chinchillas by using PG (60%), 5 -fluorouracil was used to inhibit growth of the cholesteatoma, with satisfactory results.…”

Section: Introductionmentioning

confidence: 99%

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Efeito do ácido trans-retinóico na inibição de colesteatoma em cobaias

Antunes

Fukuda

Penido

et al. 2008

Rev. Bras. Otorrinolaringol.

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Middle ear cholesteatoma affected more than 5 million people until the 80`s. Many animal models were used, unsuccessfully, to study an alternative therapy to cholesteatoma. Aim: observe the effect of the trans-retinoic acid in the inhibition of middle ear cholesteatomas induced by propylene glycol. Study Design: Clinical and Experimental. Methods: 25 guinea pigs were submitted to the application of a 100% propylene glycol solution in their bulla bilaterally and a solution of trans-retinoic acid was applied locally in the external right ear, while in the left ear saline solution was applied (control ear). The guinea pigs were slaughtered and their temporal bones were prepared for macroscopic and histological analysis. Results: The macroscopic findings had evidenced the presence of cholesteatoma in 25% of the right ears and 85% of the left ears (P=0.0003 *). The histological study had evidenced the presence of cholesteatoma in 30% of right ears and 75% of the left ears (P=0.0104*). Conclusion: The local use of the trans-retinoic acid is effective in inhibiting the induced formation of cholesteatomas in guinea pigs.

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