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Biomedical subjects

B H Britton

Publications and source records attributed to B H Britton.

At least 19 recordsLinked to original sources
PubMed1999

Pediatric eighth cranial nerve schwannoma without evidence of neurofibromatosis.

Schwannomas of the eighth cranial nerve are rare in children. We report a 4 10/12 - year-old girl with no evidence of neurofibromatosis who presented with facial droop. Radiographic studies revealed a large cerebellopontine angle tumor. At surgery, the tumor was attached to the eighth cranial nerve and histologically was a schwannoma. This is the youngest reported case of unilateral eighth cranial nerve schwannoma in a patient without the stigmata of neurofibromatosis.

Child, Preschool↗
PubMed1998

Serotoninergic innervation of stapedial and tensor tympani motoneurons.

Retrograde tracing and neurotransmitter immunohistochemistry were combined to determine whether serotonin neurons innervated stapedial and tensor tympani motoneurons. With high-power light microscopy, putative axo-somatic and axo-dendritic contacts were observed between serotonin-positive endings and both stapedial and tensor tympani motoneurons, indicating that serotonin neurons terminate on brainstem motoneurons innervating the middle-ear muscles. With this connection, the serotonin system may directly modulate middle-ear muscle activity.

Immunohistochemistry↗
PubMed1998

Effects of para-chlorophenylalanine (pCPA) on the bush baby auditory brainstem response.

Click-evoked auditory brainstem responses were recorded in a prosimian primate, the bush baby (Otolemur garnettii), before and after depletion of serotonin (by systemic injection of para-chlorophenylalanine; pCPA) and up to 20 days after discontinuing pCPA injections (during the recovery of serotonin). Biphasic 100 micros clicks were presented at five repetition rates (13.2, 33.2, 53.2, 73.2, and 93.2 clicks/s; RATE) and sound pressure levels (SPL) were varied in 10 dB steps from 120-60 dB SPL peak equivalent. Absolute latencies of vertex-positive peaks I, III, IV, and V were measured from click onset. The latencies from each wave were statistically analyzed with a two-way analysis of variance using either RATE or SPL (but not both) and TIME AFTER pCPA as independent variables. Prior to pCPA, brainstem response latencies increased as a function of both decreasing SPL and increasing RATE. After pCPA, these normal increases in wave latency increased even more, particularly in response to high click rates. After pCPA was discontinued, measurements taken at weekly intervals indicated that latencies decreased after 1 week, increased to the highest values recorded after 2 weeks, and returned to normal after 3 weeks. These dynamic changes were interpreted to be the result of postsynaptic receptor up-regulation during the 10 days of continuous pCPA administration. These results suggest that serotonin plays an important role in sensory processing at the cellular level and, tonically, facilitates the auditory brainstem response to sound.

Animals↗
PubMed1994

Serotonin and serotonin receptors in the central auditory system.

Immunohistochemical and ligand-binding techniques were used to visualize the neurotransmitter serotonin and one of its receptors, the 5-HT1A subtype, in auditory nuclei of the brainstem. Serotonergic fibers and terminal endings were found in all auditory nuclei extending from the cochlear nucleus to the inferior colliculus, including the superior olivary complex and the nuclei of the lateral lemniscus. The density of the innervation varied between and within each nucleus. All serotonergic cell bodies were located outside the auditory nuclei. The 5-HT1A receptor subtype was found in the cochlear nucleus as well as in the inferior colliculus. With no serotonergic cell bodies present in the auditory nuclei, the present neuroanatomic and neurochemical findings support behavioral and neurophysiologic findings that the serotonergic system may modulate central auditory processing.

Animals↗
PubMed1990

Lateral temporal bone resections.

Eighteen consecutive patients underwent a lateral temporal bone resection for the treatment of tumors originating in the auricle, the external auditory canal, the periauricular skin, or the parotid and were retrospectively analyzed. The different lateral temporal bone resections performed have been categorized into four types. The type I resection consists of the removal of the tympanic bone and the external auditory canal lateral to the tympanic membrane. The type II resection consists of the removal of the entire tympanic bone, the tympanic membrane, the incus, and the malleus, preserving the facial nerve and the inner ear. Type III resections remove, in addition to the those structures removed in type II resections, the distal facial nerve and fallopian canal, the mastoid tip, the styloid process, and the stylomastoid foramen. The type IV resection consists of the removal of only the mastoid tip and the inferior portion of the tympanic bone. When the techniques of lateral temporal bone resection are used appropriately, adequate surgical treatment of patients with selected advanced and recurrent malignant tumors of the external ear, the periauricular skin, and the parotid is possible with low morbidity and a high probability of local regional control.

Adult↗
PubMed1989

Schwannoma of the facial nerve in the cerebellopontine angle presenting with hearing loss.

Schwannomas of the facial nerve in the cerebellopontine angle are unusual. The authors describe a 43-year-old woman with progressive hearing loss and dizziness who had a small schwannoma of the facial nerve in the cerebellopontine angle without extension into the internal auditory canal. The tumor was completely removed with preservation of facial nerve function. The diagnosis and management of facial nerve schwannomas are discussed.

Adult↗
PubMed1988

Bruit caused by aberrant carotid artery in the middle ear.

An aberrant course taken by the internal carotid artery during its development may lead it through, rather than anterior to, the middle ear space. The resulting symptoms and signs, including a pulsatile bruit in and around the ear and the presence of a mass behind the tympanic membrane, require differentiation from those of glomus jugulare tumor.

Carotid Artery, Internal↗
PubMed1988

Cooperative neuro-otologic management of acoustic neuromas and other cerebellopontine angle tumors.

Over a recent 16-month period, 35 cerebellopontine angle tumors were removed at our institution by a surgical team consisting of one neurosurgeon and one otologist. Nineteen tumors were less than 2 cm in diameter and six were greater than 4 cm. There were 26 acoustic neuromas, six meningiomas, two epidermoid tumors, and a glossopharyngeal schwannoma. A suboccipital transmeatal approach was used in the majority of patients. There were no deaths. Thirty-two patients had an excellent outcome. Twenty-four patients had complete tumor removal (92% of the acoustic neuromas). The facial nerve was preserved anatomically in all but one patient, who had nerve grafting intraoperatively and has partial recovery of function. Thirteen of the 24 patients who had auditory function retained some of it postoperatively. With current diagnostic techniques, combined with the neurosurgical and otologic team approach, the majority of patients with acoustic tumors of all sizes may expect a complete resection of the tumor with a good outcome. Certainly, early diagnosis and resection of smaller tumors will increase the likelihood that hearing will be preserved, thus providing impetus for aggressive diagnostic and surgical treatment of patients with these lesions.

Adolescent↗
PubMed1988

Vertigo in the pediatric and adolescent age group.

Since episodic vertigo in the pediatric and adolescent age group is unusual and therefore not well known to most otolaryngologists, we present six cases to show some of the various presentations and different underlying causes. These cases covered a wide diagnostic spectrum: meningioma, medulloblastoma, childhood migraine with vestibular symptoms, childhood Meniere's syndrome (one case due to perilymph fistula), and benign paroxysmal vertigo of childhood. The two patients with tumor and the patient with perilymph fistula were treated surgically; the other patients are being managed conservatively since these childhood conditions usually tend to diminish with time.

Adolescent↗
PubMed1986

Vestibular responses to pressure variations: a review.

A selected review of the literature concerning different forms of pressure stimulation of the normal and abnormal vestibular labyrinth is presented. On the basis of this review, it can be stated that there are definite vestibular signs and symptoms associated with pressure stimulation. The exact mechanisms remain in doubt. The responses, however, appear to be mediated through the vestibular hair cells.

Air Pressure↗
PubMed1980

An evaluation of revision stapes surgery.

The expected success rate in primary stapedectomy is well documented in recent literature, but few reports have commented on the difficulties or the expected results in revision stapes surgery. Reports have dealt with different techniques, but the surgeon and the patients should be aware of the problems and risks involved in revision stapedectomy. The records of 35 patients who had undergone revision stapedectomy were analyzed to determine the following: 1. cause of failure, 2. how to avoid these difficulties, 3. hearing results, and 4. possible identifying factors which might pinpoint those patients with a high risk for sensorineural hearing loss. A review of these cases demonstrates that the results of revision stapedectomy are different than those for primary stapedectomy.

Hearing Loss, Sensorineural↗
PubMed1980

Nonotogenic otalgia: diagnosis and treatment.

Nonotogenic otalgia may be due to referred or reflex pain, neuralgia, or to a psychogenic problem. Referred pain is due to irritative lesions involving the fifth, ninth, or tenth cranial nerves and spinal nerves C2 and C3. If pathologic problems in the area supplied by these nerves have been ruled out, the neuralgia should be considered in the differential diagnosis. Psychogenic factors must be identified and treated before any type of surgical therapy is recommended.

Ear↗
PubMed1978

Lipomas of the internal auditory canal.

We present two cases of lipoma of the cerebellopontine angle (CPA), which brings, to our knowledge, the total reported in the literature to six. These cases had a clinical, surgical, and postoperative course that was similar to a small acoustic neuroma. The roentgenographic aspects were in keeping with small, CPA tumors. A review of the literature of CPA tumors and lipomas of the CNS is presented. We discuss the controversy surrounding the origin of lipomas of the CNS.

Adult↗