ABSTRACT
Eustachian tube (ET) function was evaluated bilaterally by use of the inflation-deflation and forced-response test before and after nasal challenge with various doses of histamine in five adult and 10 infant rhesus monkeys (Macaca mulatta). Of the 20 experiments conducted on the infant and juvenile monkeys, functional ET obstruction resulted in six ears after a dose of 0.5 mg of histamine, in 10 ears after a dose of 1 mg, and in four ears after a dose of 2 mg. In contrast, of the 10 experiments conducted on the adult monkeys, functional ET obstruction developed in two ears after a dose of 1 mg of histamine and in two ears after a dose of 4 mg. Six ears failed to respond at doses of 8 mg of histamine. The ET obstruction was characterized by increases in the values of the passive function parameters and an abolition of the ability to equilibrate applied middle ear pressures by muscular activity. ET obstruction was not observed in any ears after challenge with a saline control. The severity of the induced ET obstruction was lessened within 60 minutes after challenge. These data are similar to those reported for intranasal pollen challenges in sensitized rhesus monkeys and human volunteers and suggest that type I allergic reactions at the site of the nasopharyngeal mucosa disrupts the normal functioning of the ET by a mechanism potentially mediated by histamine release.
Subject(s)
Acoustic Impedance Tests , Eustachian Tube/physiopathology , Histamine/administration & dosage , Acoustic Impedance Tests/methods , Administration, Intranasal , Animals , Constriction, Pathologic/physiopathology , Dose-Response Relationship, Drug , Ear, Middle/physiopathology , Macaca mulatta , PressureABSTRACT
Past studies showed that surgical clefting of the palate resulted in impaired active eustachian tube (ET) function and otitis media with effusion (OME) in a Rhesus monkey model. In the present study, this model was used to evaluate the effect of palatal healing on ET function in eight juvenile Rhesus monkeys. Following insertion of bilateral tympanostomy tubes and collection of baseline ET function data, the soft palate was surgically clefted to the right of the midline, and bilateral ET function tests were repeated weekly until the cleft had healed. Results showed that tubal function was severely compromised on the right side but was relatively unaffected on the left side following surgical clefting; active muscular-assisted function was more affected than the passive function; and the abnormal function was reversible with healing of the cleft.
Subject(s)
Cleft Palate/physiopathology , Eustachian Tube/physiopathology , Animals , Cleft Palate/complications , Cleft Palate/surgery , Macaca mulatta , Otitis Media with Effusion/etiology , Otitis Media with Effusion/physiopathology , Palate, Soft/surgeryABSTRACT
In an attempt to better understand the etiology of middle ear disease in humans with cleft palate, a rhesus monkey model was developed. In this study, the model was extended to deal with the specific problem of otitis media in infants with cleft palate. Fifteen rhesus monkeys, Macaca mulatta, were utilized in the present investigation. Soft palate clefts were surgically produced in ten of the subjects, and five served as unoperated controls. Longitudinal data on middle ear status and craniofacial growth were collected until an approximate age of 2 years. Comparisons of linear regression coefficients representing size and rates of growth of craniofacial dimensions were made between operated and control group animals. No significant (p less than .05) differences were found between the groups. It is concluded that surgically produced clefts of the soft palate alter middle ear function and produce ear disease but do not change the rates of growth of the measured components of the craniofacial complex.
