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Biomedical subjects

D A Shea

Publications and source records attributed to D A Shea.

11 recordsLinked to original sources
PubMed1989

Otologic histopathology of Fabry's disease.

Fabry's disease is a rare progressive X-linked recessive disorder of glycosphingolipid metabolism. The accumulation of glycosphingolipids occurs in virtually all areas of the body, including the endothelial, perithelial, and smooth-muscle cells of blood vessels, the ganglion cells of the autonomic nervous system, and the glomeruli and tubules of the kidney. Although otologic symptoms have been described in these patients, to our knowledge there have been no temporal bone histopathologic reports. We describe the clinical histories, audiometric results, and temporal bone findings of two patients with this rare disorder. Both patients demonstrated a bilateral sloping sensorineural hearing loss audiometrically. Middle ear findings of seropurulent effusions and hyperplastic mucosa were seen in all four temporal bones. Strial and spiral ligament atrophy in all turns, and hair cell loss mainly in the basal turns, were also common findings. The number of spiral ganglion cells was reduced in all temporal bones; however, evidence of glycosphingolipid accumulation was not observed in the spiral ganglia.

Audiometry↗
PubMed1985

Clinical-histopathological correlations in experimental otitis media: implications for silent otitis media in humans.

Clinical-histopathological correlations were sought in an experimental animal model of otitis media. Among 20 chinchillas inoculated intranasally with wildtype influenza A/Alaska virus (H3N2) and type 7F Streptococcus pneumoniae, 15 animals (18 ears) developed otoscopic and tympanometric signs of otitis media with middle ear effusion. Middle ear inflammation was most intense 10 days after virus inoculation. Twenty-two days after virus inoculation, eight ears showed diffuse middle ear histopathology and contained effusion, which cultured pneumococcus, five ears showed focal histopathology, and four of the five contained no effusion. Clinical manifestations of otitis media had disappeared in four of the 13 ears with pathology at sacrifice; otoscopy was normal in all four ears, tympanometry was normal in three ears, and both otoscopy and tympanometry were normal in one ear. All four of these ears with clinically "silent" middle ear histopathology had shown abnormalities of ear drum appearance or tympanometry between 7 and 14 days after inoculation. Discordance between histopathology and the clinical examination performed at sacrifice was greatest for ears with focal pathology.

Acoustic Impedance Tests↗
PubMed1984

Tympanic membrane changes secondary to tympanostomy tube insertion in chinchillas.

Tympanostomy tubes were inserted in 16 chinchillas to study the effect on tympanic membrane morphology. Tympanic membranes were examined with an operating microscope after 72 hours and at weekly intervals thereafter. Three ears developed postoperative otorrhea. Except for the ears with otorrhea, all tympanic membranes remained gray and translucent. Histologically, granulation tissue and polymorphonuclear leukocyte infiltration occurred around the tympanostomy tube by 7 days. With time this was replaced by a mature fibrous ring, which explained the tissue band observed otoscopically. In those tympanic membranes where the tympanostomy tube had extruded, healing occurred with an overly developed membrana propria. The middle ears of all experimental animals remained free of pathologic changes except for the three ears with otorrhea.

Animals↗
PubMed1983

Tympanostomy tubes and otic drops.

Otic drops have been proposed as a form of prophylaxis against the otitis media which follows middle ear contamination by water in patients with tympanostomy tubes. The potential adverse effects of this form of therapy were studied in chinchillas with tympanostomy tubes; 31 chinchillas underwent bilateral tympanostomy tube insertion. Seven animals had a mixture of green dye and Cortisporin otic suspension placed in both external auditory canals 24 hours following the placement of tympanostomy tubes and were sacrificed 30 minutes later for gross examination; 3 of these animals had previous eustachian tube obstruction with Silastic sponge. Twenty-one animals had Cortisporin otic suspension placed in the right external auditory canal on postoperative days 3, 4, 5, 6 and 7. No otic drops were placed in the left ear. Ten of these 20 animals had VIIIth nerve action potentials measured on postoperative day 17 and the other 11 animals had VIIIth nerve action potentials measured on postoperative day 42 followed by immediate sacrifice for histological examination and scanning electronmicroscopy. The remaining 3 animals had VIIIth nerve action potentials measured 21 days following tympanostomy tube insertion and served as electrophysiological controls. The 8 ears receiving Cortisporin otic drops mixed with green dye from animals with normal eustachian tubes showed staining of the round window membrane at sacrifice, while the 6 ears receiving Cortisporin otic suspension and green dye from animals with eustachian tube obstruction demonstrated no dye in the middle ear. All animals receiving Cortisporin otic drops in the right ear showed an intra-aural difference in action potentials with the right ear being attenuated by an average of 10.3 dB at 2,000 Hz, 12 dB at 4,000 Hz, 21 dB and 8,000 Hz, and 26 dB at 12,000 Hz. Morphological study revealed hair cell loss in the hook portion of the cochlea in those animals receiving Cortisporin otic drops. It was concluded from this study that, in patients with patent tympanostomy tubes in place, potentially ototoxic topical agents should be used with caution.

Action Potentials↗
PubMedDate not supplied

Effect of tympanostomy tubes on the pathogenesis of acute otitis media.

Intubation of the tympanic membrane as a treatment for acute otitis media is extremely controversial. This study was designed to determine the effect of tympanic membrane intubation in an experimental model for acute purulent otitis media. The right tympanic membrane of the chinchilla was intubated with Paparella Type I tympanostomy tubes. This procedure was followed in seven days by nasopharyngeal inoculation of Streptococcus pneumoniae and in an additional three days by nasopharyngeal inoculation of influenza A virus. Nasopharyngeal inoculation with these microorganisms results in acute purulent otitis media in 70 per cent of animals. The presence of the tympanostomy tubes did not reduce the incidence of clinical otitis media, nor did it reduce the pathologic changes within the middle ear space. The tympanostomy tubes did, however, significantly reduce the incidence and severity of pathologic changes in the subepithelial space of the middle ear mucosa.

Acute Disease↗
PubMedDate not supplied

Mucopolysaccharidosis I-H (Hurler's syndrome) and human temporal bone histopathology.

Six temporal bones from three patients with mucopolysaccharidosis I-H are described. All three patients were diagnosed as having mucopolysaccharidosis I-H by enzyme analysis, and all fit the phenotypic criteria of this disease. Family histories of the three cases described were negative for mucopolysaccharide-storage diseases. All three of the patients suffered chronic recurrent otitis media from infancy through death. Common histopathologic findings include otitis media, residual mesenchyme in the round window niche, partial occlusion of the middle ear cavity, and basophilic concretions within the stria vascularis. The common severe histopathologic changes observed in this study and similar findings in the temporal bones described in other studies lead the authors to believe that ear involvement in this disease may be more common than was previously suspected.

Child↗
PubMedDate not supplied

Silent otitis media: an animal study.

Recent clinical and laboratory observations suggest that otitis media can occur in the absence of visible tympanic membrane changes (silent otitis media). Temporal bone histopathology was studied in 38 chinchillas that had been subjected to conditions known to predispose these animals to otitis media. Morphological changes were compared to a control group of 25 nonmanipulated animals. The tympanic membranes were examined at intervals and during the immediate premortem period with the operating microscope. Thirty-one tympanic membranes in the experimental group and all tympanic membranes in the control group were judged to be normal (gray and translucent) throughout the study period. The middle ears from the experimental group histologically manifested varying amounts of effusion, mucosal edema, granulation tissue, hyperemia of the subepithelial space, hemorrhage in the middle ear space, and abundant polymorphonuclear leukocytes in the middle ear cleft. These findings were not present in the control group.

Animals↗
PubMedDate not supplied

Experimental pneumococcal otitis media: a histopathologic study.

An animal model for pneumococcal otitis media was studied histologically at varying intervals postinoculation. Histologic changes generally associated with acute inflammation (edema, diffuse infiltration with polymorphonuclear leukocytes, and hemorrhage) occurred early in the disease while the ears were culture positive. Changes generally associated with chronic otitis media (lymphocyte infiltration and osteoneogenesis) occurred later in the course of the disease when the ears were culture negative. Metaplasia of middle ear mucosa and middle ear granulation tissue were observed as early as five days following inoculation. Middle ear granulation tissue was identified in 82% of all cases; cholesteatoma was seen in only one ear. Tympanic membrane perforation did not occur. Labyrinthitis and endolymphatic hydrops were fairly common findings. The former was identified in 56% of ears examined, and the latter, in 45%. These two conditions coexisted in 34% of ears studied, while endolymphatic hydrops alone occurred in 11%.

Acute Disease↗
PubMedDate not supplied

Otitis media, cleft palate, and middle ear ventilation.

Chinchillas with unilateral tympanostomy tubes in place underwent palate-clefting in an effort to determine the histologic and bacteriologic effects of using tympanostomy tubes in the treatment of otitis media. The tympanostomy tube appeared to almost totally eliminate the occurrence of middle ear effusion but had much less, if any, effect on eliminating the middle ear inflammation which occurs in the clefted chinchilla.

Animals↗
PubMedDate not supplied

Sac decompression for refractory luetic vertigo.

Luetic hydrops can occur in both congenital and acquired lues and otologic manifestations may be indistinguishable from Meniere's disease. Eight endolymphatic sac decompression procedures were performed on 6 patients with refractory luetic vertigo. Of those, 3 had congenital and 3 acquired lues. All cases had received extensive anti-luetic medical therapy without any discernible improvement in the vertiginous attacks. In our 6 patients with luetic hydrops the main complaint was severe refractory vertigo, indeed, disabling in most cases. Postoperatively, all cases remained free from these severe attacks and the vertigo was controlled or eliminated in all cases. Although hearing was improved in one patient, hearing seemed not to improve, generally speaking, as a result of the long-term postoperative follow-up. We describe our method of sac decompression and drainage and suggest that this procedure might be considered for patients with uncontrollable luetic vertigo who have not benefited from adequate medical therapy.

Adult↗