Faculty Bibliography

The development of inhibitory synaptic transmission is difficult to assess because the afferents usually arise from intrinsic neurons that are difficult to stimulate independently. The postnatal maturation of excitatory and inhibitory synaptic function was compared in the gerbil lateral superior olive (LSO), where it is possible to stimulate physically discrete afferent projections. Intracellular recordings obtained in a brain slice preparation revealed that transmission was prominent at birth. The EPSPs and IPSPs were up to 2 orders of magnitude longer than in more mature animals. Brief trains of electrical stimulus pulses led to a temporal summation of postsynaptic potentials (PSPs) in 1-14 d animals resulting in prolonged depolarizations or hyperpolarizations. In neonates, the depolarization could exceed 1 sec following a 70 msec stimulus train. The IPSPs in neonates were often of sufficient amplitude to evoke a rebound depolarization or action potential. The number of converging afferents was estimated from the quantized increases in PSP size. There was a significant decrease with age, suggesting that both inhibitory and excitatory afferents were eliminated during the first 3 postnatal weeks. The integration of action potentials with IPSPs was examined with conjoint stimuli to the two afferent pathways, and demonstrated that the effective IPSP duration decreased approximately 20-fold during the first 3 postnatal weeks. The magnitudes and durations of electrical stimulus-evoked PSPs suggest that spontaneous discharge of afferents to the LSO could have a substantial impact on their development, even prior to the response to airborne sound at 12 d. Furthermore, the synaptic responses obtained at 12-14 d postnatal indicated that both amplitude and temporal processing remain compromised. These immature synaptic properties would be expected to compound the inadequacies present in the cochlea and cochlear nucleus

This study assessed the achievement of postoperative swallowing in patients undergoing partial laryngectomy surgery. Oropharyngeal swallow efficiency was used to predict time to achievement of outcome. Fifty-five patients were followed for up to 1 year in two hemilaryngectomy and four supraglottic laryngectomy groups. Within 10 days of healing, a videofluoroscopic evaluation enabled the measurement of swallowing efficiency. Times to achievement of oral intake, removal of feeding tube, preoperative diet, and normal swallow were analyzed using actuarial curves. Patients with hemilaryngectomies achieved swallowing rehabilitation sooner than patients with nonextended supraglottic laryngectomies (p < .05) who, in turn, achieved swallowing function sooner than did patients undergoing supraglottic laryngectomies with tongue base resection (p < .05). Median time to attainment of preoperative diet in these three groups was 28 days, 91 days, and > 335 days, respectively. Higher early postoperative oropharyngeal swallow efficiency was related to earlier achievement of oral food intake and of preoperative diet (p < .05). Results show that the time course for swallowing rehabilitation covers an extended postoperative period. In some surgical groups, functional swallowing and eating may be achieved within 3 months of surgery while for other types, significant impairment remains up to 9 months postoperatively Early radiographic assessments of swallowing function are useful in predicting the time to swallow recovery. Recovery of swallowing ability may be delayed in patients who have not achieved oral intake before radiotherapy is started

Hyperbaric oxygen (HBO) promotes tissue healing by increasing oxygenation. Therefore, HBO therapy is clinically useful for some patients who have undergone major cancer resection and/or radiotherapy to the head and neck. For individual patients, however, there might be undetected viable tumor present at the time of therapy. This study was performed to determine if increased tissue oxygen had a measurable effect on the growth of squamous carcinoma xenotransplants which had been derived from head and neck cancers. After the successful growth of two well-established human squamous cell carcinoma cell lines (183 and 1483), each tumor was transplanted into 20 mice. Every mouse received four transplants of 10(6) cells. Ten mice with 40 xenotransplants in each group were treated with HBO daily for 90 minutes at a pressure of 2 atm, whereas the other 10 formed the control group. The mice transplanted with cell line 1483 were treated for 21 days; mice transplanted with cell line 183 were treated for 28 days. The tumor weight, volume, and histology were evaluated. No significant difference was found between experimental groups. This study suggests that increased tissue oxygen neither significantly increases nor decreases the growth of squamous cell carcinoma

Cigarette smoking is a major risk factor for head and neck cancer, and individuals who continue to smoke past diagnosis and treatment are at elevated risk for further disease. In a randomized controlled trial, a state of the art provider-delivered smoking cessation intervention was compared to a usual care advice control condition. The intervention consisted of surgeon- or dentist-delivered advice to stop smoking, a contracted quit date, tailored written materials, and booster advice sessions. Subjects were 186 patients with newly diagnosed first primary squamous cell carcinomas of the upper aerodigestive tract who had smoked cigarettes within the past year. At randomization, 88.2% of subjects were current smokers. At 12-month follow-up, 70.2% of subjects completing the trial (n = 114) were continuous abstainers; among baseline smokers alone the continuous abstinence (CA) rate was 64.6%. The cotinine validation rate at 12 months was 89.6%. Modeling techniques were utilized in order to derive expected CA rates, which included noncompleter subjects (n = 72). The CA rate expected at 1 year for the entire patient population was 64.2%, and for smokers alone the expected CA rate was 59.4%. Logistic regression analysis carried out on baseline smokers identified predictors of 12-month CA status. These included medical treatment, stage of change, age, nicotine dependence, and race. The intervention effect was not significant, although the sign of the effect was positive. Based on these findings, we recommend systematic brief advice to stop smoking for head and neck cancer patients, with a stepped care approach for patients less able to quit.

Glomus jugulare tumors have been reported to secrete norepinephrine and cause severe hypertension with features similar to pheochromocytoma. In contrast, epinephrine secretion has not been observed in these neoplasms. This has been attributed to the absence of the norepinephrine-methylating enzyme, phenylethanolamine-N-methyltransferase (PNMT), required for epinephrine synthesis. We report a patient with severe hypertension caused by a glomus tumor that secreted norepinephrine and epinephrine. Following selective venous sampling, catecholamines were quantified by radioenzymatic assay. Marked elevations in norepinephrine and epinephrine release were localized to the glomus tumor. The enzymes involved in catecholamine biosynthesis, including PNMT and tyrosine hydroxylase, were identified immunocytochemically in the tumor. The glomus tumor had staining patterns identical to those observed within normal rat glomus cell. Hypertension resolved with resection of the functioning tumor. This is the first report of PNMT in a functioning paraganglioma of the glomus jugulare region. The factors that determine why functional activity is expressed only rarely by paraganglioma remain undefined.

Eight patients 45 years of age and under (range, 29 to 45) with squamous cell carcinoma of the head and neck and infection with the human immunodeficiency virus are reported. Primary tumor sites include nasopharynx, oral cavity, oropharynx, and larynx. Probes for the human papillomavirus were positive in two of the patients. Therapy consisted of surgery followed by radiation therapy in five patients, surgery alone in one patient, and radiation therapy in the remaining two patients. Follow-up ranged up to 2 years and revealed four deaths, three patients alive without disease, and one patient recently posttreatment with residual disease. The significance of the presence of the human papillomavirus in these individuals remains to be determined. The incidence of squamous cell carcinoma of the head and neck under age 45 is low, and whether there may be a higher incidence in HIV-positive patients cannot be determined from this small series

Articulatory and acoustic data were used to explore the following hypothesis for the vowel /u/: The objective of articulatory movements is an acoustic goal; varying and reciprocal contributions of different articulators may help to constrain acoustic variation in achieving the goal. Previous articulatory studies of similar hypotheses, expressed entirely in articulatory terms, have been confounded by interdependencies of the variables being studied (e.g., lip and mandible displacements). One case in which this problem may be minimized is that of lip rounding and tongue-body raising (formation of a velo-palatal constriction) for the vowel /u/. Lip rounding and tongue-body raising should have similar acoustic effects for /u/, mainly to lower F2. In multiple repetitions, reciprocal contributions of lip rounding and tongue-body raising could help limit F2 variability for /u/; thus this experiment looked for complementary covariation (negative correlations) in measures of these two parameters. An electro-magnetic midsagittal articulometer (EMMA) was used to track movements of midsagittal points on the tongue body, upper and lower lips, and mandible for large numbers of repetitions of utterances containing /u/. (Interpretation of the data was aided by results from area-function-to-formant modeling.) Three of four subjects showed weak negative correlations, tentatively supporting the hypothesis; a fourth showed the opposite pattern: positive correlations of lip rounding and tongue raising. The results are discussed with respect to ideas about motor equivalence, the nature of speech motor programming, and potential improvements to the paradigm

Auditory brainstem responses (ABRs) were recorded from 20 normal neonates and 10 normal-hearing adults. The spectral compositions of ABRs from both groups were compared. Results indicated that significant amounts of low-frequency information are concentrated below 150 Hz in both the neonate and the adult ABRs although the neonate ABR has a slightly greater percentage of low-frequency information than that of the adults. This has implications for filtering during ABR recording. A low high-pass setting which preserves more of the low-frequency information will allow enhanced detectability of wave V in neonate ABRs recorded at low stimulus intensities. Furthermore, our experience indicates that the use of a 30- to 3,000-Hz bandpass is feasible in the neonatal intensive care unit as well as in the regular newborn nursery. Therefore the use of a 30- to 3,000-Hz bandpass is recommended for neonate ABR recordings.