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Biomedical subjects

M Hawke

Publications and source records attributed to M Hawke.

At least 55 records · Page 3Linked to original sources
PubMed1991

Ossicular erosion by cholesteatoma: investigation by scanning electron microscopy utilizing a new preparation technique.

A new technique for removing the soft tissues from middle ear ossicles to prepare them for scanning electron microscopy is described. The technique involved use of a solution of hypochlorite. The bony surface of normal ossicles was studied as a control group after preparation by the technique and no morphological distortion was observed. Ossicles eroded by cholesteatoma were then studied, and we propose that the erosion occurs in three stages; pumicing, pitting and cavitating. The mucoperiosteum of normal ossicles and otosclerotic foci were also studied.

Cholesteatoma↗
PubMed1991

Persistence of the foramen of Huschke in the adult: an osteological study.

The foramen of Huschke, which appears during the embryological development of the tympanic bone, usually closes by the age of five years. A review of 377 dried skulls revealed that the foramen of Huschke was present in adult life in 7% of the skulls examined. A patent foramen of Huschke in the adult may, in rare cases, be the cause of temporomandibular joint herniation or fistulization through the anterior wall of the bony external canal.

Adult↗
PubMed1991

The motility of keratinocytes in cholesteatoma: an ultrastructural approach to epithelial migration.

Eight cases of attico-antral cholesteatoma were studied by transmission electron microscopy concentrating on the mechanisms involved in intercellular adhesion. Desmosomes were found in large numbers throughout the epidermis and were arranged in various orientations around the keratinocytes. Those desmosomes found in the stratum corneum were significantly less dense than those in deeper layers and were associated with a large number of intercellular spaces, which would reduce the cohesive strength of this layer. The tortuous basement membrane features numerous hemidesmosomes along its length. The findings of this study were compared with previous ultrastructural observations made on the pars flaccida and pars tensa of the tympanic membrane and external canal skin. This revealed that the morphological characteristics of cholesteatoma resemble pars flaccida and external canal skin rather than pars tensa. The implications of these findings are discussed.

Cell Movement↗
PubMed1990

Quelprud's nodule: a post-auricular cartilaginous nodule.

A number of minor variations to the configuration of the external ear are well recognized. This paper brings attention to one entity which is characterized by a small cartilaginous nodule or prominence arising from the posterior surface of the pinna and which we have named Quelprud's nodule. A prospective clinical survey of 208 patients attending an ENT clinic revealed that nearly one-third of the population studied possess this nodule. There was an equal sex incidence. The Quelprud's nodule was identified within families in a distribution which suggests an autosomal dominant inheritance with variable expressivity.

Adolescent↗
PubMed1990

Impacted cerumen: a disorder of keratinocyte separation in the superficial external ear canal?

In the majority of individuals, impaction of cerumen in the external auditory canal does not occur, and it is only a fraction of the population who regularly need to consult their physician for aural toilet. In this study we looked at the clinical features associated with recurrent cerumen impaction in 20 individuals. This was complemented by an examination of the cerumen plugs taken from their ears and hydrated to analyze the morphology of the keratin sheets, which had been observed in a previous study to constitute over one-half of the volume of impacted cerumen. In a further eight patients with cerumen, impaction plugs of cerumen were removed and subjected to histological examination. We observed that excessively long sheets of undivided keratin could be isolated from the hydrated cerumen plugs and that these sheets of keratin morphologically resembled the superficial layers of the stratum corneum of normal human deep external auditory canal skin. Based on these observations, we propose that cerumen impaction is the result of a failure in the normal keratinocyte separation which occurs in the superficial external auditory canal.

Cerumen↗
PubMed1990

Glomus bodies in the temporal bone.

There are very few studies in the literature of the anatomy of glomus bodies in the temporal bone, and their function in the normal ear remains undiscovered. In this study, human, squirrel monkey, and cat temporal bone sections were examined by light microscopy for the presence of glomus bodies, and the anatomy and distribution of glomus bodies in the temporal bone is described. For the first time, glomus bodies have been identified in non-human temporal bone sections. A possible function for these chemoreceptor-like structures in the ear is discussed.

Adolescent↗
PubMed1990

The perilymphatic fistula: the end of an enigma?

While the existence of a perilymphatic fistula may be suggested on the basis of a patient's history and physical findings, at present the diagnosis can only be established by the identification of the actual fistula at the time of tympanotomy. In some cases, repeated reaccumulation of clear colorless fluid within the middle ear is interpreted as representing perilymph and has been considered to indicate the presence of a fistula that cannot be visualized. This subjective type of observation is made by the operating surgeon and is consequently subject to bias. At the present time there is no objective method, such as histopathology, to confirm the diagnosis of a perilymphatic fistula in this type of situation. As a result, there is some variation and controversy in the otology literature as to what surgical findings at tympanotomy should be considered as "proof" of a perilymphatic fistula. In this paper we will propose a new method for confirmation of the diagnosis of perilymphatic fistulas based on a unique biochemical property of perilymph.

Ear Diseases↗
PubMed1990

Steroid sulfatase activity in the skin of the external ear canal.

Steroid sulfatase is an enzyme which has an important role in the complex process of cell desquamation. The specific activity of this enzyme was found to be higher in the epithelium of the deep external auditory canal than in the epithelium of the superficial external canal. We speculate that this steroid sulfatase activity gradient is involved in the outward migration of the keratinocytes of the canal epithelium.

Analysis of Variance↗
PubMed1990

Outer ear canal shape and its relation to the effectiveness of sound attenuating earplugs.

This investigation was undertaken to explore the relationship between the level of sound attenuation achieved by the wearing of hearing protectors, and the shape of the external ear canal. Bilateral molds of the outer portion of the external ear canal were made in 93 males and females with normal hearing, who had participated in a previous study on the effect of gender on sound attenuation, measured for a variety of insert type devices. The ear canal molds were analyzed in terms of tortuosity, caliber, and degree of funneling. The results showed that individuals with straight canals achieved significantly higher attenuation scores than those with twisted canals. With regard to caliber, the more important of the two parameters reviewed was the cross-sectional area of the canal measured at the cartilaginous-bony junction (IA). The relationship between IA and attenuation depended on both gender and the type of earplug tested. Funneling, measured by the ratio of concheomeatal and cartilaginous-bony cross-sectional areas, had the opposite effect of that for IA. These findings underscore the need for more controlled prescription and fitting procedures for the insert type of hearing protectors commonly used in the industrial setting.

Ear Canal↗
PubMed1989

Histopathologic consequences of surgical approaches to the singular nerve.

Selective sectioning of the singular nerve has proven successful in the relief of incapacitating benign positional vertigo (BPV), presumably on the histopathologic basis of posterior ampullary cupulolithiasis. Although the surgical techniques of transmeatal and the recently introduced retrosigmoid IAC approach have been well described, little has been written about the singular nerve's anatomical relationships determined histologically for each surgical approach. The anatomical relationships of the singular nerve in both the transmeatal and retrosigmoid IAC approaches are discussed. Histologic evidence presented suggests that other mechanisms may also be ultimately responsible for improvement in the symptoms of BPV following transmeatal surgery. Moreover, the high incidence of injury to the endolymphatic duct during retrosigmoid surgery raises questions about the exact role of the endolymphatic duct and sac in inner ear homeostasis.

Ear, Inner↗
PubMed1989

The mechanism of ceruminolysis.

In a previous study comparing the efficacy of a selection of commonly used ceruminolytics, the authors noted that aqueous-based preparations, and in particular solutions of sodium bicarbonate, were more effective in disintegrating cerumen than most organic-based preparations. In that study, the authors also observed that not only had the wax truly disintegrated following exposure to the aqueous-based preparations, but also that a marked degree of swelling of the wax spheres had occurred with these preparations. In this paper the mechanism of ceruminolysis was investigated by means of a number of commonly available histological techniques. Our findings show that desquamated sheets of corneocytes are the major constituent of cerumen plugs and provide the structural framework of the wax bolus. Ceruminolytics work by hydrating the keratin cells of these sheets of desquamated stratum corneum and subsequently inducing keratolysis, with disintegration of the wax.

Antipyrine↗