Faculty Bibliography

1. Although synaptic transmission is known to influence many aspects of neuronal development, activity rates are quite low at early ages. The present study describes a long-lasting postsynaptic response to brief periods of synaptic stimulation that may underlie such an influence. Whole-cell patch clamp recordings were made from the lateral superior olive (LSO) in a brain slice preparation from early postnatal gerbils. 2. Stimulation of the excitatory afferent pathway from the cochlear nucleus elicited a prolonged depolarization (PD) in approximately 60% of the LSO neurons tested. Low frequency stimulation (1 Hz) was as effective as tetanic stimulation in producing PDs. These synaptically evoked depolarizations ranged in amplitude from 3 to 32 mV and recovered spontaneously after 0.5-35 min. 3. The LSO neuron input resistance declined during every PD episode and remained significantly lower even after the membrane potential had recovered. These PDs were partially reversed by 2 mM Ni(+2), but 1 microM tetrodotoxin and 10 microM 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) were ineffective. The metabotropic glutamate receptor agonist, trans-1-aminocyclopentane-1,3-dicarboxylic acid (40 microM), produced depolarizations that outlasted the exposure period by an average of 20 min and were also partially repolarized by 2 mM Ni(+2). In contrast, the depolarizations produced by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid or N-methyl-D-aspartate decayed within a much shorter period of time. 4. To test whether in vivo discharge rates are, in fact, very low during development, spontaneous activity was recorded from neurons of the auditory midbrain in gerbils before and during the onset of sound-evoked responses. The average discharge rate of auditory neurons was quite low (X = 0.4 spikes/s), although many cells displayed brief periods of rapid discharge rate (X = 37 spikes/ s). Together, these results demonstrate a novel form of developmental plasticity elicited by low rates of glutamatergic transmission that may involve a metabotropic pathway and prolonged calcium influx

We present two cases of massive gingival enlargement and osteolysis of alveolar bone in a 30-year-old female and a 36-year-old male. The etiology could not be established in either case. Histologically, both lesions contained hyperplastic fibrous connective tissue and intense plasma cell infiltrates. Both patients responded well to extensive gingivectomy, extraction of all teeth, and alveoplasty

20 cadaver mandibles were studied for the presence of an antilingula and its relationship to the true lingula and mandibular foramen. Three independent observers evaluated the mandibles for the presence of an antilingula. It could be identified on all 40 sides. On 9 of the sides, there was complete concordance on the position of the antilingula between the three observers. On the other 31 sides, however, there was a variation between observers of up to 11 mm. In only 43% of the cases was the antilingula within 5 mm of the true lingula. In most cases, the true lingula was postero-inferior to the antilingula. There was a negative horizontal and positive vertical correlation between the position of the antilingula on one side and its position on the contralateral side

This study examines the relationship of time to cochlear implant patient performance and the effect of device design on patient performance over time. Data were collected for patients who were implanted with Nucleus 22, Smith & Nephew Richards Ineraid, or 3M/Vienna cochlear implants as part of the Veterans Administration study on cochlear implants. Patients were administered a comprehensive audiological test battery prior to implantation, at stimulation, and 3 months, 1 year, and 2 years poststimulation. Results show that patient performance improved over the course of the study, with performance levels with each multichannel implant being similar at the study end point. The Nucleus device produced maximum performance sooner than the Ineraid device did, and performance of the single-channel 3M was consistently below that of the multichannel devices

The otolaryngologist is frequently consulted for paranasal sinus disease which has been identified as an incidental finding on computed tomography (CT) in children. The significance of such a finding is difficult to interpret without prior knowledge of the actual incidence of chronic sinus mucosal hypertrophy in the general pediatric population. In this study of pediatric CT scans from busy otolaryngology and ophthalmology clinics, the radiographic incidence of sinus disease in the general pediatric population is estimated. One hundred forty-two CT scans of the orbits and temporal bones obtained over an 18-month period were reviewed. Fifty-eight (41%) scans showed some mucosal thickening or opacification in at least one sinus. When patients were stratified by age, or by the presence or absence of chronic otitis media or respiratory tract disease, exclusive of clinical sinusitis, there was no statistical difference between groups. The authors conclude that the asymptomatic child with an incidental paranasal sinus finding on CT scan need not be worked up further unless clinical symptoms and signs are elicited.

OBJECTIVE: To create an experimental model of Streptococcus pneumoniae type 3 meningogenic labyrinthitis (a leading cause of deafness) similar to that in human disease. DESIGN: Cohort analytic study of guinea pigs that were inoculated intrathecally with varying dilutions of S pneumoniae type 3; the progress of the disease was compared with that in saline solution-inoculated control animals. SUBJECTS: Healthy adult Hartley guinea pigs without clinical evidence of middle ear disease that were conveniently sampled. INTERVENTIONS: Intrathecal inoculation of 10(4) to 10(6) colony-forming units of S pneumoniae type 3 into 13 guinea pigs; signs and symptoms of meningitis/labyrinthitis were observed for 15 days and compared with those in two saline solution-inoculated control animals. MAIN OUTCOME MEASURES: Morbidity--labyrinthitis, meningitis; end point--death. RESULTS: The 10(4) to 10(6) colony-forming units of S pneumoniae type 3 caused inflammation that extended from the meninges to the inner ear via the cochlear aqueduct within 3 days after inoculation; a dose of 10(7) killed animals within 12 hours after inoculation. Three of five animals that were inoculated with a 10(6) dose died 3 days after inoculation; two of three animals that were inoculated with a 10(5) dose lived to 15 days after inoculation. One of two animals that were inoculated with a 10(4) dose did not become infected. Inflammation extended to the middle ear by round-window destruction. Reactive bone formation simulated labyrinthine osteosclerosis. Observers assessed histologic slides "blindly." CONCLUSION: Guinea pigs can survive 15 days after intrathecal inoculation of a 10(5) dose, with morphologic features similar to those in human disease. This is an effective model for this study of meningogenic labyrinthitis.

Disorders of communication have high incidence and prevalence in the fetus, neonate, and infant, and optimal care is dependent on early recognition and intervention. This article reviews receptive disorders, expressive disorders, and their diagnoses.