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

NF is a potentially lethal infectious process usually found in the abdomen, perineum, or extremities. In the head and neck it usually starts from a dental infection but can be initiated from any source. One of the more serious sequelae is extension of the infection down the deep fascial planes of the neck leading to mediastinitis; this is associated with a higher mortality rate. The presence of an associated immunocompromising disease, such as diabetes, has been said to predispose an individual to NF, and the mortality rate has been shown to be higher (although perhaps not significantly so). When first described, NF was thought to be caused only by beta-hemolytic Staphylococcus. Now it known to be a polymicrobial infection with anaerobes and facultative anaerobes found most frequently. Treatment involves broad-spectrum intravenous antibiotics as soon as possible, narrowing the coverage as the results of the gram stain and cultures become available. The importance of aggressive, prompt surgical management cannot be overemphasized in the treatment of NF. Once the diagnosis of NF is strongly suspected, debridement of the affected areas must be accomplished as soon as possible. Despite the advances in the recognition and treatment of NF, there is still significant morbidity and mortality associated with this disease. Continued vigilance must be practiced if the survival rate is to continue to increase

BACKGROUND: Bronchospasm after intravenous hydrocortisone treatment has been reported in some patients with aspirin-sensitive respiratory disease. OBJECTIVE: This study was designed to determine the prevalence of sensitivity to hydrocortisone among patients with aspirin-sensitive respiratory disease. METHODS: We performed double-blind, placebo-controlled challenges with aspirin and 100 mg of hydrocortisone sodium succinate administered intravenously in 53 subjects. RESULTS: Forty-five of the 53 subjects (85%) undergoing oral aspirin challenge experienced respiratory reactions to aspirin. Forty-four of these 45 patients had neither naso-ocular, cutaneous, nor respiratory reactions to hydrocortisone sodium succinate. One aspirin-sensitive subject had bronchospasm and a naso-ocular reaction to hydrocortisone sodium succinate and a naso-ocular reaction with minimal bronchospasm to methylprednisolone sodium succinate. After desensitization to aspirin, and while receiving maintenance aspirin therapy, this subject again reacted to hydrocortisone sodium succinate with bronchospasm and naso-ocular reaction. CONCLUSION: We conclude that aspirin-sensitive patients with asthma are not preferentially sensitive to hydrocortisone and that hydrocortisone sodium succinate does not cross-react or cross-desensitize with aspirin

Successful prevention of bone loss in ovariectomized rats with 17 beta-estradiol (E2) at 10 micrograms/kg/d has been reported. Here we show that E2 dose twice that much is not enough to maintain PTH(1-34) mediated bone gain. Three-month-old female Wistar rats were ovariectomized and fed with regular rodent chow and water ad libitum. Three months later they were divided into 9 groups (5-8 per group) and treated cyclically with PTH(1-34) (20 micrograms/kg/d sc, 5d/w for 3w) and E2 (20 micrograms/kg/d sc, 5d/w for 4w). There were also a baseline group and five vehicle control groups. Cancellous bone volume (Cn.BV/TV) of distal femoral metaphyses was measured by computer-aided histomorphometry on trichrome stained thin sections, and 24-hour fasted urine was analyzed for pyridinoline/creatinine (PYR/CREA) by immunoassay. Histomorphometric results showed that PTH(1-34) progressively increased Cn.BV/TV but E2 failed to maintain them. Urinary PYR/CREA results showed that E2-treated groups had lower values. We conclude that E2 dose > 20 micrograms/kg/d is required to maintain the PTH mediated bone gain.

Posttransplantation lymphoproliferative disorder (PTLD) is a well-described complication of the systemic immunosuppression required for successful organ transplantation. Lesions of PTLD often occur in the region of the head and neck and require otolaryngologic evaluations. Although the majority of reported cases of PTLD are associated with cyclosporine immunosuppression, recently, PTLD has been described in patients treated solely with the newer systemic immunosuppressive agent tacrolimus (FK 506). As an introduction to tacrolimus and to PTLD as one of its complications, a case of PTLD presenting as airway obstruction in a child treated solely with tacrolimus immunosuppression is described. In addition, a review of tacrolimus and PTLD in patients under tacrolimus immunosuppression is presented to familiarize the otolaryngologist with this important new immunosuppressive agent and a potential complication of its use