Faculty Bibliography

Mutant alleles of MYH9 encoding a class II non-muscle myosin heavy chain-A (NMMHC-IIA) have been linked to hereditary megathrombocytopenia with or without additional clinical features that include sensorineural deafness, cataracts, and nephritis. To assess its biological role in the affected targets, particularly the inner ear, we have generated and characterized mice with Myh9 deficiency. These mice were generated using the XA136 ES cell line (BayGenomics, http://baygenomics.ucsf.edu/) carrying gene trap insertion in Myh9, within the intron flanking exons 4 and 5. Mice heterozygous for the Myh9 null allele, Myh9 +/- were expanded on C57BL/6J background. Intercross of the Myh9 +/- mice did not yield Myh9 -/- pups, indicating embryonic lethality, subsequently determined to occur at or before E7.5, thus precluding a post-natal analysis of the effects of complete Myh9 deficiency. The heterozygous mice were normal for their hearing, parameters of platelet integrity and renal function despite their Myh9 haplo-insufficiency. In addition, the age-dependent auditory threshold of the Myh9 +/- mice and their wild type littermates, spanning from 3 to 12 months of age, were similar indicating that Myh9 haplo-insufficiency does not contribute towards accelerated age-related hearing loss (AHL). The embryonic lethality associated with the complete Myh9 deficiency establishes a critical role for this non-muscle myosin in fetal development. The results of these studies do not support the Myh9 haploinsufficiency as a pathogenic factor in the etiology of auditory dysfunction

INTRODUCTION: Diagnosis and management of perilymphatic fistula (PLF) is a controversial topic in the international neurotologic literature. An illustrative case of post traumatic PLF with clear surgical indications is presented. This manuscript also reviews the various clinical presentations, pathogenesis, diagnostic examinations, and management options of PLF. MATERIALS AND METHODS: Case report and literature review. RESULTS: A 40 y/o female presented with paroxysmal vertigo, imbalance and severe sensorineural hearing loss (SNHL) following minor occipital head trauma from a fall six months prior to presentation. Laboratory examination included intermittently positive fistula sign on video-nystagmography. Patient failed to respond to trials of pharmacologic treatment and bedrest and ultimately underwent surgical exploration and repair. Patient had earlobe fat placed in the round and oval windows. Postoperatively, she had prompt resolution of vestibulopathy and ultimate full return of sensorineural function. CONCLUSIONS: Patients with appropriate antecedent history demonstrating fluctuating SNHL and vestibulopathy, failing to respond to conservative medical treatments, should be considered for exploratory tympanotomy. In the absence of any other violations of labyrinthine integrity, connective tissue grafting of the round and oval windows should be performed even if no obvious flow of fluid is observed. This management protocol is safe and effective in properly selected patients.

BACKGROUND: Sexual history taking is a core clinical skill for all physicians, yet many medical schools do not adequately address this important topic within the curriculum. This article describes a sexual-history-taking module that was initiated, designed, and presented by 2nd-year medical students for their peers as part of the required Introduction to Clinical Medicine (ICM) course. DESCRIPTION: As part of this module, a group of 2nd-year medical students developed a large-group presentation and small-group role play cases to enhance students' basic sexual-history-taking skills in challenging situations, teach ways to ask nonjudgmental questions, and introduce legal issues that may arise. Under faculty supervision, the students recruited and trained peer and faculty facilitators and designed, developed, and analyzed the survey evaluation tools. EVALUATION: Both the students and facilitators completed an anonymous questionnaire within 1 to 4 weeks of completing the activity. Of the 92 students completing an online survey, 92% rated the large group presentation good or excellent, and 89% rated the small-group role playing activities as good or excellent, as compared to overall ICM course ratings of 68% good or excellent. Facilitators were well prepared for their roles and reported that the students responded to them positively. Participating students reported that having students as teachers positively enhanced their small group learning experience. Students performed better on the sexual-history-taking questions on the final examination (97.5%) than on the final examination overall (89%). CONCLUSIONS: Medical students can successfully create and implement a curriculum module for their peers in a sensitive area such as sexual history taking. Due to changing responsibilities for students as they progress through medical school, sustainability may be challenging.

Normal perception depends, in part, on accurate judgments of the temporal relationships between sensory events. Two such relative-timing skills are the ability to detect stimulus asynchrony and to discriminate stimulus order. Here we investigated the neural processes contributing to the performance of auditory asynchrony and order tasks in humans, using a perceptual-learning paradigm. In each of two parallel experiments, we tested listeners on a pretest and a posttest consisting of auditory relative-timing conditions. Between these two tests, we trained a subset of listeners approximately 1 h/d for 6-8 d on a single relative-timing condition. The trained listeners practiced asynchrony detection in one experiment and order discrimination in the other. Both groups were trained at sound onset with tones at 0.25 and 4.0 kHz. The remaining listeners in each experiment, who served as controls, did not receive multihour training during the 8-10 d between the pretest and posttest. These controls improved even without intervening training, adding to evidence that a single session of exposure to perceptual tasks can yield learning. Most importantly, each of the two groups of trained listeners learned more on their respective trained conditions than controls, but this learning occurred only on the two trained conditions. Neither group of trained listeners generalized their learning to the other task (order or asynchrony), an untrained temporal position (sound offset), or untrained frequency pairs. Thus, it appears that multihour training on relative-timing skills affects task-specific neural circuits that are tuned to a given temporal position and combination of stimulus components