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Biomedical subjects

W J Doyle

Publications and source records attributed to W J Doyle.

At least 145 records · Page 8Linked to original sources
PubMed1982

Morphology of the middle ear in the rhesus monkey (Macaca mulatta).

The purpose of this study was to provide a description of the morphology of the middle ear and related structures in the rhesus monkey, Macaca mulatta. From these descriptions, it can be seen that except for relative size differences, the middle ear system of the rhesus monkey bears close resemblance to that of man. The basic architecture is the same, thereby providing an anatomic foundation for the observed similarities in function [Cantekin et al,, 1981]. The few differences between the two systems can be summarized as follow: (1) The angle of inclination of the medial wall on the parasagittal plane is more acute in the rhesus monkey than in man. (2) The shape of the tympanic membrane in the monkey is almost circular compared to the irregular oval shape in man. (3) Differences in the shape of the ossicles as well as differences of relative measurements and angles between the parts of the ossicles were observed. (4) A major difference involves the pneumatic system and most prominently, the absence of a definite mastoid process in the monkey. However, the mastoid portion of the temporal bone is still very cellular in the majority of the specimens and communicates with the middle ear cavity through a well-defined mastoid antrum. The well-developed and extremely cellular petrous bulla in the monkey is absent in man.

Animals↗
PubMed1982

Canine model of subglottic stenosis secondary to prolonged endotracheal intubation.

Acquired subglottic stenosis is usually a consequence of prolonged endotracheal intubation. The present study describes a canine model of subglottis stenosis which is congruent with the known and suspected pathogenesis of the disease in man. Eighteen young pups (Canis familiaris) were used. A modified cuffed endotracheal tube was placed within the subglottis and secured by inflating the cuff. The capillary tube supplying the cuff was sealed and cut so as to lie below the epiglottis. Three animals died of tracheal rupture or collapse prior to or on the thirteen day following intubation. In the remaining animals, the cuffed tube was removed and the subglottis was examined. All exhibited ulcerations and exuberant polyploid granulations at the level of the subglottis and trachea. A 4 mm uncuffed endotracheal tube was introduced and secured within the subglottis and trachea of a number of the pups to provide an airway. After a 3-week period, the tube was removed and the dogs were sacrificed. Examination of the specimens showed various degrees of "hard" cicatricial stenosis of the subglottis and trachea. Histologic studies showed destruction of the cartilage with replacement by scar tissue and partial epithelialization. This model may be useful to investigations of the prevention and treatment of the disease.

Animals↗
PubMed1982

Anomalous middle ear gas absorption in a non-human primate model of cleft palate.

Following surgical clefting of the palates of nine Rhesus monkeys (Macaca mulatta), daily recordings of the middle ear pressure by tympanometry have shown fluctuations between high positive and negative values. High positive middle ear pressures were recorded during the recovery from otitis media, and it was suggested that these pressures were the result of a learned or reflexive autoinflation of the middle ear cavity. To test this hypothesis, animals presenting high positive middle ear pressures were anesthetized with sodium pentobarbital, and serial tympanograms were obtained at 5-minute intervals for a period of four hours. The results showed a substantial and rapid decrease in middle ear pressure following anesthesia (200 to 400 mm H2O). These findings were compared to those of similar experiments in normal animals, with near zero resting middle ear pressures or following air and oxygen politzerizations. The changes in middle ear pressure of cleft palate animals were significantly greater than those recorded for normal animals with near zero resting middle ear pressure and were essentially the same as those recorded for normal animals following air politzerization. These data suggest that abnormally high positive middle ear pressures are the result of an introduced bolus of air. This mechanism may serve as a means of ventilating the middle ear cleft in lieu of a debilitated active dilatory mechanism, and as such, may aid in the resolution of the middle ear effusion.

Absorption↗
PubMed1982

The nasopharyngeal orifice of the auditory tube: implications for tubal dynamics anatomy.

This is the first part of a study designed to clarify the relationship between auditory tube dilation and observed movement of the nasopharyngeal orifice of the tube. This report seeks to delineate the anatomical parameters of the system, whereas, the second will report on findings of torus "movement" observed during simultaneous tympanometric measurements of tubal function during swallowing. The disposition of the paratubal musculature, relation between the tubal cartilage and the cranial base, relations between the cartilage and the medial pyterygoid plate, relation between the two cartilaginous laminae, and the presence of a heavy coat of soft tissue over the torus were findings felt to indicate that movement of the tubal cartilage in swallowing cannot occur. Nasopharyngoscopic reports of "cartilage" movement during swallowing may be observations of soft tissue sliding over the torus and not torus movement itself.

Cartilage↗
PubMed1981

Recurrent pneumococcal otitis media in the chinchilla. A longitudinal study.

To define the relative importance of the local and systemic immune mechanisms in otitis media, middle ear infections were induced in 47 chinchillas by unilateral intrabullar inoculation of Streptococcus pneumoniae type 6A. Bacterial challenges were repeated ipsilaterally or contralaterally several times during the five-month course of the study. The middle ear condition was assessed with the use of otomicroscopy, tympanometry, and direct inspection and culture through a bullar opening. Pneumococcal 6A antibodies were assayed periodically in the serum and middle ear effusions. The concentration levels of serum antibodies did not correlate with the course of otitis media, and antibiotics did not protect either the ipsilateral or contralateral ear from infection. There was a minimal number of bacteria that rendered the middle ear resistant to subsequent infection. This resistance was a local phenomenon and occurred only when the middle ear had previously been exposed to the same bacteria.

Animals↗
PubMed1979

The interaction of stressors in the induction of increased levels of fluctuating asymmetry in the laboratory rat.

Recent studies on fluctuating dental asymmetry have isolated single stressors as causative agents. Since most stressors are composite in nature, the present study was designed to determine the effects of the interaction of stressors in the induction of fluctuating dental asymmetry. Pregnant rats were assigned to one of six treatment groups and stressed with various combinations of heat, cold, noise and protein deprivation. The levels of fluctuating dental asymmetry were assessed and it was found that all protocols produced higher levels of asymmetry than found for control animals. Noise and reduced protein exhibited an additive effect and the interaction of stressors produced a reduction in litter size. Suggestions were offered for further research in this expanding field.

Animals↗
PubMed1979

Longitudinal assessment of Eustachian tube function in children.

Eustachian tube function was evaluated in 27 children (32 ears) with tympanostomy tubes at 6-week intervals for 12 to 30 months. Using a modified inflation-deflation test of passive and active ventilatory function, it was found that the ears had persistent functional obstruction. Most ears exhibited no significant change in tubal function throughout the observation period. There was no difference in the ventilatory function when the nasal airway was congested (other than due to purulent upper respiratory tract infection) and not congested. However, significant seasonal effects on Eustachian tube ventilatory function were recorded: function was poorer in the winter than in the summer. No relationship was found between Eustachian tube ventilatory function and the age of the child.

Adolescent↗
PubMed1979

Anatomy of the auditory tube and related structures in the rhesus monkey (Macaca mulatta).

The primate nasopharynx-auditory tube-middle ear complex is being used by several researchers to model both normal and pathologic functions of the human auditory tube. An extensive search of the literature has indicated little detailed information on the primate tube/middle ear system. This study was undertaken to define the anatomical characteristic of the system in the rhesus monkey (Macaca mulatta) and to determine the limits on the use of the monkey as a model of human tubal function. Although the direct application of morphologic data to account for the observed function of a system is a tenous one, the data on the rhesus monkey auditory tube appear to be consistent with those published for other mammals. The tensor veli palatini muscle appears to be the only muscle to act directly on the tube and effect tubal dilation. The muscle is attached to the lateral membranous tubal wall along its extrabullar extension. The muscle has an inferior attachment to the posterior hard palate and thus possesses a vector directed inferolaterally; contraction would appear to pull the membranous wall inferiorly and laterally, resulting in tubal dilation. The auditory tube relationships of the salpingopharyngeus, levator veli palatini, and internal pterygoid muscles are described. Their possible role in primate tubal function is minimal at best.

Animals↗
PubMed1979

Scapular correlates of muscle morphology in Papio cynocephalus.

The scapula responds to the compressive states of its surrounding matrix produced by muscle functioning and weight bearing in the upper extremity with discernible structural correlates. These structural correlates can be utilized to infer locomotor behavior. After dissection and drying, the weights of several muscles of the shoulder region of 11 adult female baboons (Papio cynocephalus) were statistically compared to various dimensions of the bony scapula. A significant correlation was obtained between the weights of the individual compressive muscles, the combined weights of the compressive muscles and a scapular dimension of width. A nonsignificant correlation between these muscles and a sscapular dimension of length was also found. The results of this study were compared to those of a previous study of the scapular musculature in Macaca and opposing conclusions were obtained. The advisability of lumping macaques and baboons into a single gross locomotor category is rejected.

Animals↗
PubMed1978

Microbiology of recurrent and chronic otitis media with effusion.

A study was conducted of 274 children who had recurrent acute or chronic otitis media with effusion. Forty-five percent of the ears with effusion were found to contain bacteria, and 11% contained bacteria that were "probable pathogens" (S. pneumoniae, H. influenzae, and S. pyogenes). Bacteria were also found in 40% of the ears without effusions. The type of organism found did not vary with the age of the patient studied or the season of the year. The significance of these bacteria in the etiology of recurrent acute or chronic otitis media with effusion remains to be demonstrated.

Acute Disease↗
PubMed1977

Heat stress, fluctuating asymmetry and prenatal selection in the laboratory rat.

Recent studies have demonstrated that stress may increase the fluctuating asymmetry of teeth and limbs in laboratory animals. The present study investigates the effects of heat on such parameters. Pregnant laboratory rats are exposed to temperatures of 33 degrees C during gestation. Increases in fluctuating asymmetry of dental dimensions as well as bone density are found for the pups of such females when compared to unstressed controls. A general increase in limb lengths is also reported for young of heat stressed animals. Prenatal selection with differential survival is suggested as a possible explanation for differences found between the experimental and control animals.

Animals↗
PubMed1977

On the meaning of increased fluctuating dental asymmetry: a cross populational study.

Suarez reports a greater magnitude of fluctuating dental asymmetry for Neandertal sample when compared with a sample of modern Ohio whites. He postulates that this greater antimeric variance could be due to a greater degree of inbreeding in the Neandertal populations. In the present investigation, the magnitude of fluctuating dental asymmetry is evaluated for Eskimo and Pueblo populations. These populations were found to exhibit dental variance of equal magnitude to that of the Neandertal population. As these populations are not highly inbred, a stress related mechanism is suggested to explain these observations and the inbreeding hypothesis is rejected. The implications of this mechanism to Brace's Probable Mutation Effect are discussed.

Bicuspid↗
PubMed1977

Functionally induced alteration of adult scapular morphology.

The dependence of the growth and development of the scapula on its functional matrix has been clearly defined by a number of experimental studies. Early modifications of this functional matrix may result in an altered scapular morphology [Howell, 1917]. Further, extreme developmental muscular hypofunction results in an increase in scapular breadth and a decrease in length [Riesenfeld, 1966; Doyle, 1976]. However, these studies have been confined to the scapular growth period and no findings have been published on the effect of scapular hypofunction in adults. The present paper addresses this problem. Adult scapular hypofunction in the rat was produced by unilateral amputation of the upper arm. Statistically significant (p less than 0.001) differences in intraindividual scapular breadth dimensions are reported. Further, an increase in the relative instability of the scapular length dimension was observed. No differences in gross scapular morphology resulted from the hypofunctional condition. It is concluded that the functional matrix of the scapula determines a unique morphology during the course of development. Once established, scapular morphology is relatively fixed and only unstable dimensions such as breadth are predictably responsive to a changed matrix.

Animals↗