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Biomedical subjects

W L Meyerhoff

Publications and source records attributed to W L Meyerhoff.

At least 109 records · Page 6Linked to original sources
PubMed1977

Pseudomonas mastoiditis.

Opportunistic infections of the external auditory canal or the middle ear due to Pseudomonas aeruginosa occurring in patients with low resistance to infection have a 35 percent mortality rate. Once the process extends into the pneumatized temporal bone, eradication becomes more difficult and the mortality rate increases to 72 percent because of the high incidence of involvement of cranial nerves, adjacent intracranial vessels, and meningitis. Treatment is directed towards the underlying condition, administration of systemic carbenicillin and gentamicin, topical colistin therapy, and judicious surgical debridement. Pseudomonas vaccine may be of help. Fifteen cases are presented. Nine follow the pattern of malignant external otitis and six began as a primary acute otitis media.

Adult↗
PubMed1976

Sudden deafness.

Explore the source record for details and available documents.

Adult↗
PubMed1976

Reduction of mandibular fractures.

The decision to reduce a mandibular fracture by closed or open intraoral or extraoral techniques is not simple and depends upon multiple factors. That decision can be made only by the surgeon who understands the nature of the injury, the forces acting upon the injury site, and the relationship of the injury to other mandibular structures and to surrounding tissue. Other factors to consider include dentition and occlusion and an understanding of the healing processes, including the effects of concurrent disease and associated and distant trauma.

First Aid↗
PubMed1975

Styloid process neuralgia: myth or fact.

Five cases of enlogated styloid processes sent in a 12-month period prompted a review of this subject and a reevaluation of the condition as it relates to other neuralgias of the head and neck. We review the head and neck pain syndromes and offer diagnostic criteria that will aid in the differential diagnosis and will facilitate appropriate management.

Aged↗
PubMed1975

Carcinoma of the lip.

A retrospective analysis of 206 patients with lip cancer is presented. Poorly differentiated primary lesions have a high rate of metastases. The metastatic potential of well differentiated lesions, when classified by size in the TNM staging system, is the same as that of intraoral carcinoma. A therapeutic approach is proposed.

Adult↗
PubMedDate not supplied

Angiographic variant in juvenile nasopharyngeal angiofibroma.

A 17-year-old male with juvenile nasopharyngeal angiofibroma was found, on preoperative evaluation, to have a normal selective angiogram of the internal and external carotid artery system. Possible explanations for this variant include an atypical blood supply from the vertebral artery system, the thyrocervical trunks, or from an ascending pharyngeal artery that branched low from the external carotid artery.

Adolescent↗
PubMedDate not supplied

Effect of 5-fluorouracil in cholesteatoma development in an animal model.

This investigation was designed to evaluate the effects of the antimetabolite 5-fluorouracil (5-FU) on cholesteatoma formation in a chinchilla model. The animals received middle ear applications of propylene glycol according to a procedure previously shown to produce cholesteatomas in 60% to 70% of animals. A 5% solution of 5-FU was then applied to the lateral surface of the tympanic membrane (TM) and, after 1 month, temporal bones were taken for histologic study. No macroscopically visible cholesteatomas were present in any of the 16 temporal bones included in the study. However, microscopic invasion of epidermis to the medial side of the TM was observed in four specimens; perforations were present in three of these. Although there was considerable variability in the response to 5-FU application, the majority of specimens showed little or no proliferation of connective tissue in the lamina propria of the TM. In the four specimens in which epidermis reached the medial side of the TM, it did so either by migration through microscopic breaks in the fibrous layer or via TM perforations. Thus, 5-FU did not completely inhibit migration of epidermis into the middle ear. However, the results of this study indicate that it does tend to reduce the proliferation of TM epidermis and connective tissue, thereby reducing the likelihood of cholesteatoma formation in the experimental model.

Animals↗
PubMedDate not supplied

Summating-potential/action-potential ratio in normal ears: effects of dehydration.

INTRODUCTION: Studies using electrocochleography (ECoG) in patients with Meniere's disease and in patients with perilymph fistula have demonstrated abnormally large summating-potential (SP) components compared with the amplitude of the action-potential (AP). The possible influence of normal physiological variation, methodological differences, and test-retest variations are often difficult to interpret. The purpose of this study is to specify what constitutes a clinically important change in the SP/AP ratio in normal hearing subjects under the condition of dehydration induced by urea. MATERIALS AND METHODS: Baseline ECoG was performed on 20 normal hearing volunteer subjects after an 8 hour fast. Urea, 20 g, was administered orally, following which recordings were made at 60 and 90 minutes. The majority of subjects were found to have maximal SP/AP changes at 60 minutes post dehydration; therefore, only these results were included in the final analysis. Subsets of data were statistically evaluated. RESULTS: In all ears but one, the preingestion SP/AP ratio was less than or equal to 0.37. Male and female data were shown to comprise separate populations both before and following dehydration. The 95% upper limit for baseline SP/AP ratio was 0.39 for males and was 0.25 for females. The gender-related difference remained after dehydration. The mean male SP/AP ratio showed a statistically significant but slight decrease whereas the female SP/AP ratio was unaltered. CONCLUSION: These data demonstrate a statistically significant gender-related difference in SP/AP ratio in normals. The upper limit of normal is 0.39 for males and 0.25 for females. A basis for the gender difference is puzzling and requires further investigation. Dehydration produces a statistically significant reduction in SP/AP ratio in men. This change was not observed in women.

Action Potentials↗
PubMedDate not supplied

Effect of topical hyaluronic acid on experimental cholesteatoma.

PURPOSE: Inflammation and connective tissue hyperplasia are believed to be important etiological factors in cholesteatoma pathogenesis. Previous work has shown that topically applied hyaluronic acid can reduce connective tissue proliferation in healing wounds and accelerate healing of tympanic membrane perforations. This study was undertaken to determine whether the antiproliferative effect of hyaluronic acid may inhibit propylene glycol-induced cholesteatoma in an animal model. MATERIALS AND METHODS: A 60% propylene glycol solution was injected bilaterally into the middle ear cavities of 20 adult chinchillas. The control group (N = 10) received propylene glycol alone. In addition to propylene glycol injections, the experimental group (N = 10) received repeated bilateral topical applications of 1.5% hyaluronic acid onto the tympanic membranes. Animals were killed at 4 weeks for gross and light microscopic examination. RESULTS: Seven control and 10 experimental animals survived the full 1-month study period. At the end of that time, cholesteatoma was found in 71% (10/14) of control ears and 70% (14/20) of experimental ears. Tympanic membrane structure did not differ significantly between groups by light microscopy and, in all animals, cholesteatomas originated by migration of hyperplastic epidermis through the tympanic membrane, as has been observed in previous studies using this animal model. CONCLUSION: Under the conditions of this study, topical hyaluronic acid had no significant effect on cholesteatoma formation.

Administration, Topical↗
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

Ototoxicity of otic drops applied to the middle ear in the chinchilla.

Previous studies have shown that the application of topical otic drops to the external ear canals of animals with patent tympanostomy tubes may result in hearing impairment and cochlear hair cell loss. Otic drops are used in patients with tympanostomy tubes or tympanic membrane perforations and could have deleterious effects on the human membranous labyrinth. This report describes the inner ear damage that occurred after direct application of aminoglycoside-containing otic drops to the middle ears of experimental animals. The membranous labyrinths of 25 chinchillas were studied two days to five months after application of Cortisporin otic suspension (which contains neomycin, polymyxin B, hydrocortisone, and propylene glycol) to the middle ear cavity. Application of 0.5 ml of Cortisporin resulted in degeneration of all inner and outer hair cells throughout the cochlea, as well as severe damage to the stria vascularis. Moderate to severe degeneration of the vestibular receptor organs was also observed. The endolymphatic sacs showed dark-staining endolymph, cellular debris, and macrophages in the sac lumina, as well as increased activity of the epithelial lining.

Animals↗
PubMedDate not supplied

Middle ear cholesteatoma: an animal model.

Topical otic preparations now in clinical use contain a variety of antibiotics and solvents that may produce severe inflammation if they reach the middle ear cavity. This report describes the response of the chinchilla middle ear to direct application of one such preparation that appears to act as a nonspecific irritant. Cortisporin otic suspension (containing neomycin, polymyxin B, hydrocortisone, and propylene glycol) was introduced into the bullae of 32 chinchillas that were kept alive for four days to five months before histologic examination of their temporal bones. All the experimental animals had tissue damage and inflammation within the middle ear. The changes observed included proliferation of ciliated and secretory columnar cells, formation of granulation tissue, bone erosion, and osteoneogenesis. Some areas of the mucosa underwent metaplasia to stratified squamous epithelium; this metaplastic epithelium, however, did not produce keratin. In the majority of animals kept for two months or more, cholesteatoma was identified in the middle ear. The cholesteatomas appeared to develop as a result of penetration of external canal epidermis through intact tympanic membranes or as the result of migration of epidermis through perforations. The experimental cholesteatomas behaved like those seen clinically in humans, with extensive erosion of bony structures within the middle ear.

Animals↗
PubMedDate not supplied

Inner ear anomalies in two cases of trisomy 18.

Two cases of trisomy 18 in which temporal bone defects were limited to the inner ears are described. Several abnormalities were present that have not been described previously in this syndrome. The first case involved a 1-month-old female infant who died of congenital heart defects. Cochlear nerve fibers were absent on the left side, with near-normal innervation on the right. Although the organ of Corti was present bilaterally, some of the outer hair cells were deformed, having small rounded cell bodies unsupported by Deiters' cells. On the right, similar abnormal cells were found in the tunnel of Corti. Vestibular defects in this case included reduced nerve supply of the left saccular macula, cysts in the superior and posterior cristae, and absence of the utriculoendolymphatic valve. The second case involved a newborn male infant with multiple congenital anomalies. The major cochlear defect was a deformity of the stria vascularis. In the lower apical turn, the stria was adherent to Reissner's membrane and extended beneath it into scala media. Large capillaries, which ran freely suspended in scala vestibuli, entered the upper portion of the stria. Severe atresia of the lateral and posterior semicircular ducts was found in the vestibular apparatus.

Chromosomes, Human, 16-18↗