Faculty Bibliography

Paragangliomas of the head and neck are uncommon, slow-growing, multicentric and are usually benign. Ever since familial paragangliomas were first described a genetic explanation for their existence has been sought. An international collaboration finally elucidated the SDHB, SDHC and SDHD genes for three paraganglioma syndromes (PGL 4, 3, 1). A familial origin should be suspected if other family members have paraganglioma, paragangliomas are multiple, the patient is young or the patient has a vagal paraganglioma. Once familial disease is suspected the best initial screening method is by genetic testing of the patient in question. If genetic testing detects PGL 1, 3 or 4 mutations then the patient's siblings and children should be tested. All genotypically positive patients should be followed periodically as soon as detected. Surveillance is best performed with periodic radionuclide imaging and by directed magnetic resonance imaging. The purpose of surveillance is early detection and consequently earlier treatment. Abundant evidence exists that the risk of complications from surgical intervention increases with increasing tumor size. If tumors are detected and eradicated before they become large, then younger patients can be spared the dysphagia, dysphonia, dysarthria and stroke that have plagued patients undergoing surgery for these tumors

Restoration of the posterior maxilla involving sinus bone grafting demonstrates both surgical and prosthetic problems that treating clinicians should recognize and explain to patients prior to any invasive treatment. If a sinus graft is lost, the alternatives to treatment are explained. However, if the practitioners follow a step-by-step protocol and use retrievable prostheses, a long-term, favorable prognosis results.

A 33-year-old-man presented with a 13-year history of asymptomatic, white, folded, soft, poorly-demarcated, diffuse plaques bilaterally on his buccal mucosae and lateral surfaces of his tongue. There is no family history of similar lesions. The physical examination and histopathologic findings were consistent with a diagnosis of white sponge nevus. This rare disorder is typically inherited; however, as in this case, there have been a few other cases reported without a familial background.

OBJECTIVE: Most surgeons perform pediatric bone-anchored hearing aid (BAHA) implantation in two stages. This study examined the safety and efficacy of single-stage BAHA implantation in adults and children. METHODS: Retrospective review of 32 ears: 18 pediatric (ages 6 to 13 years) and 14 adult patients who underwent single-stage BAHA surgery between 2002 and 2006. RESULTS: A total of eight (25%) ears experienced complications. Overall, four (13%) ears required revision in the operating room. In the pediatric group, there were three (16.7%) ears with skin complications; two required operative revision. In the adult group, there were five (36%) ears with skin complications; two required operative revision. CONCLUSIONS: In both adults and children, the single-stage technique for BAHA implantation is safe and efficient. All complications were related to skin reaction. Safety profiles for 1- and 2-stage surgery are similar, although the single-stage procedure is more cost effective, avoids a second procedure, and provides for earlier hearing rehabilitation

OBJECTIVE: To determine whether differences of angles between the alar rim and the long axis of the secondary defect in a Zitelli bilobed flap affect alar displacement in a fresh cadaver model. METHODS: In fresh cadaver heads, identical, unilateral 1-cm circular defects were created at the superior alar margin. Three different laterally based bilobed flap templates for reconstruction were used. One template, used on 3 cadavers, had an angle of 60 degrees between the alar rim and the long axis of the secondary defect. Another template, used on 3 cadavers, had an angle of 90 degrees . The last template had an angle of 135 degrees and was used on 2 cadavers. Photographs were taken before the repair and after with the camera and cadaver heads in the same spatial relationship to each other. RESULTS: In the 3 cadavers that had repair using an angle of 60 degrees , all cadavers experienced alar retraction, with a mean displacement of 1.3 mm. This was not a statistically significant change (P = .07). In the defects that had repair using an angle of 90 degrees , there was also no significant alar displacement (P = .72). In the 2 cadavers that underwent repair using an angle of 135 degrees , both ala underwent depression by 1.0 mm. When the differences achieved between the different angles were compared, there was a significant difference in measured distortion between the cadavers that had 90 degrees and 60 degrees vector placement (P = .02). There were no measurable changes to the contralateral maximal nostril distance. CONCLUSIONS: Vector alignment can have an impact on nostril displacement. In bilobed flaps, the axis of the secondary defect may play an important role. This study suggests that secondary defects aligned perpendicular to the nostril have the least amount of alar distortion

Information transfer analysis [G. A. Miller and P. E. Nicely, J. Acoust. Soc. Am. 27, 338-352 (1955)] is a tool used to measure the extent to which speech features are transmitted to a listener, e.g., duration or formant frequencies for vowels; voicing, place and manner of articulation for consonants. An information transfer of 100% occurs when no confusions arise between phonemes belonging to different feature categories, e.g., between voiced and voiceless consonants. Conversely, an information transfer of 0% occurs when performance is purely random. As asserted by Miller and Nicely, the maximum-likelihood estimate for information transfer is biased to overestimate its true value when the number of stimulus presentations is small. This small-sample bias is examined here for three cases: a model of random performance with pseudorandom data, a data set drawn from Miller and Nicely, and reported data from three studies of speech perception by hearing impaired listeners. The amount of overestimation can be substantial, depending on the number of samples, the size of the confusion matrix analyzed, as well as the manner in which data are partitioned therein

All hearing aids and communication devices introduce nonlinear distortion. The perception of distortion by hearing-impaired subjects was studied using artificial controlled distortions of various amounts and types. Subjects were asked to rate the perceived quality of distorted speech and music. Stimuli were subjected to frequency-dependent amplification as prescribed by the 'Cambridge formula' before presentation via Sennheiser HD580 earphones. The pattern of the ratings was reasonably consistent across subjects, but two of the eight subjects showed inconsistent results for the speech stimuli. Center clipping and soft clipping had only small effects on the ratings, while hard clipping and 'full-range' distortion had large effects. The results indicate that most hearing-impaired subjects are able to make orderly and consistent ratings of degradations in sound quality introduced by nonlinear distortion. The pattern of results could be predicted reasonably well using a model developed to account for the perception of distortion by normally hearing subjects

MYH9 encodes a class II nonmuscle myosin heavy chain-A (NMHC-IIA), a widely expressed 1960 amino acid polypeptide, with translated molecular weight of 220 kDa. From studies of type II myosin in invertebrates and analogy with the skeletal and smooth muscle myosin II, NMHC-IIA is considered to be involved in diverse cellular functions, including cell shape, motility and division. The current study assessed the consequences of two separate, naturally occurring MYH9 dominant mutant alleles, MYH9(R702C) and MYH9(R705H) linked to syndromic and nonsyndromic hearing loss, respectively, upon diverse NMHC-IIA related functions in two separate cultured cell lines. MYH9-siRNA-induced inhibition of NMHC-IIA in HeLa cells or HEK293 cells resulted in alterations in their shape, actin cytoskeleton and adhesion properties. However, HeLa or HEK293 cells transfected with naturally occurring MYH9 mutant alleles, MYH9(R702C) or MYH9(R705H), as well as in vitro generated deletion derivatives, MYH9(DeltaN592) or MYH9(DeltaC570), were unaffected. The effects of MYH9-siRNA-induced suppression underline the critical role of NMHC-IIA in maintenance of cell shape and adhesion. However, the results also indicate that the NMHC-IIA mutants, R702C and R705H do not inactivate or suppress the endogenous wild type NMHC-IIA within the HeLa or HEK293 cell assay system. Cell Motil. Cytoskeleton 2008. (c) 2008 Wiley-Liss, Inc

PURPOSE: To retrospectively determine whether relative cerebral blood volume (CBV) measurements can be used to predict clinical outcome in patients with high-grade gliomas (HGGs) and low-grade gliomas (LGGs) and specifically whether patients who have gliomas with a high initial relative CBV have more rapid progression than those who have gliomas with a low relative CBV. MATERIALS AND METHODS: Approval for this retrospective HIPAA-compliant study was obtained from the Institutional Board of Research Associates, with waiver of informed consent. One hundred eighty-nine patients (122 male and 67 female patients; median age, 43 years; range, 4-80 years) were examined with dynamic susceptibility-weighted contrast material-enhanced perfusion magnetic resonance (MR) imaging and were followed up clinically with MR imaging (median follow-up, 334 days). Log-rank tests were used to evaluate the association between relative CBV and time to progression by using Kaplan-Meier curves. Binary logistic regression was used to determine whether age, sex, and relative CBV were associated with an adverse event (progressive disease or death). RESULTS: Values for the mean relative CBV for patients according to each clinical response were as follows: 1.41 +/- 0.13 (standard deviation) for complete response (n = 4), 2.36 +/- 1.78 for stable disease (n = 41), 4.84 +/- 3.32 for progressive disease (n = 130), and 3.82 +/- 1.93 for death (n = 14). Kaplan-Meier estimates of median time to progression in days indicated that patients with a relative CBV of less than 1.75 had a median time to progression of 3585 days, whereas patients with a relative CBV of more than 1.75 had a time to progression of 265 days. Age and relative CBV were also independent predictors for clinical outcome. CONCLUSION: Dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging can be used to predict median time to progression in patients with gliomas, independent of pathologic findings. Patients who have HGGs and LGGs with a high relative CBV (>1.75) have a significantly more rapid time to progression than do patients who have gliomas with a low relative CBV