Faculty Bibliography

The myeloproliferative neoplasm, myelofibrosis, is a morbid and frequently fatal illness encompassing primary myelofibrosis, and end-stage essential thrombocythemia and polycythemia. Bevacizumab (15 mg/kg intravenous (i.v.) every 21 days) was tested in a phase II international trial conducted by the Myeloproliferative Disorders Research Consortium. Thirteen patients were enrolled in the first stage of this 2-stage trial. Among the 11 patients who received therapy, only 3 received more than 4 cycles of therapy; none of the patients achieved an objective response. Furthermore, significant toxicity, not directly related to the vascular or gastrointestinal events typically associated with the anti-VEGF monoclonal antibody preparation in other disease states, was observed. Lack of objective responses coupled with toxicity led to the decision to terminate the study early. If future studies incorporate bevacizumab in combination therapy for myelofibrosis, more modest doses should be considered. (clinicaltrials.gov Identifier 00667277).

Statement of the Problem: Reconstruction of the atrophic edentulousmaxilla canbe a challenge, particularly in individuals where extensive bone grafting is required prior to dental implant placement or in patients where bone grafts have been tried and failed. Likewise, dental rehabilitation after tumor ablation and reconstruction can be problematic if there is inadequate maxillary bone to support traditional dental implants. Zygomaticus implants, which make use of the dense type I-II bone of the zygoma, are one solution that allows for dental implant reconstruction of the atrophic or reconstructed maxilla. Materials and Methods, Data Analysis: We performed a retrospective chart review of all patients who received dental implants in the operating room at two of our affiliated hospitals from June 2007 to March 2013. We identified those patients who received either unilateral or bilateral zygomaticus implants.We then collected available data including gender, diagnosis, adjunctive surgical procedures, and indication for zygomaticus implants. Patients receiving zygomaticus implants following maxillectomy procedures were compared to a cohort of patients who did not receive implants following maxillectomy to determine which variables may have influenced surgeon choice of zygomaticus implants. In addition, we report on two recent cases of zygomaticus implants placed followingenucleation of maxillary bone cysts. Follow-up was available for all patients and ranged from one month to five years. All implants were placed by and with the supervision of a single attending surgeon, DLH. Results: From 2007 to 2013, a total of 25 zygomaticus implants were placed in 12 patients at two affiliated hospitals. Indications for zygomatic implants were varied. Patients received zygomatic implantation for cleft reconstruction, maxillectomy defect with and without free tissue transfer, and atrophic maxilla not amenable to traditional implant surgery. Two patients received bilateral zygomaticus implants for a diagnosis of !

Cisplatin is the primary chemotherapy for head and neck squamous cell carcinoma (HNSCC). No equally effective chemotherapeutics are available when cisplatin resistance occurs. We hypothesize that DNA methylation of key genes mediates cisplatin resistance; moreover, pretreatment with decitabine, a demethylating agent, restores cisplatin sensitivity by mediating expression of genes that are instrumental to cisplatin resistance. Objectives: 1) Determine whether decitabine treatment of a cisplatin-resistant HNSCC cell line restores the anti-proliferative and apoptotic effects of cisplatin; 2) Evaluate the anti-proliferative effect of decitabine and cisplatin (i.e. combination treatment) on a preclinical HNSCC model; 3) Determine whether combination treatment reduces cancer pain; and 4) Create a "gene expression profile of cisplatin resistance" by analyzing cisplatinsensitive and cisplatin-resistant HNSCC in patients. Methods: SCC-25, a cisplatin-sensitive HNSCC cell line, and SCC-25/CP, a cisplatin-resistant cell line, were pre-treated with 5mM decitabine and then treated with cisplatin (3-300 mM) for 48 hours. Proliferation was quantified with an MTS assay. Apoptosis was quantified with a caspase 3/7 assay. A preclinical model was created by inoculating SCC-25/CP cells into the hind-paw of BALB/ c mice. Twenty-four mice were placed into one of four treatment groups: control sham, decitabine-only, cisplatin- only, or combination treatment. Decitabine (6 mg/kg) was administered on post-inoculation days (PID) seven and nine, and cisplatin (6 mg/kg) was administered on PID 12, 15, 18, and 21. Tumor growth was quantified. Mechanical allodynia (i.e. pain) was quantified with a paw withdrawal assay. Formalin-fixed, paraffin- embedded biopsies were obtained from HNSCC patients who underwent chemotherapy with cisplatin. Tumors were classified as either cisplatin-sensitive (RECIST 3 or 4) or cisplatin-resistant (RECIST 1 or 2). Gene expression was quantified in these two sets of samples. Results: In the in !

OBJECTIVES/HYPOTHESIS: To describe a novel conduction study of the laryngeal nerves, including normal values and abnormal findings. STUDY DESIGN: Prospective nonrandomized. METHODS: Seventeen healthy adult volunteers, as well as three patients with clinically identified laryngeal neuropathy, underwent low-level brief electrical stimulation of the laryngeal mucosa by means of a wire inserted via a transnasal flexible laryngoscope. Bilateral hookwire electrodes recorded the result in the laryngeal adductor muscles. RESULTS: This study yields an early response ipsilateral to the side of stimulation (LR1), which is uniform and consistent (right = 13.2 +/- 0.80 msec; left = 15.2 +/- 1.20 msec), and late bilateral responses (ipsilateral LR2 [LR2i] and contralateral LR2 [LR2c]), which exhibit greater variation in latency and morphology (right LR2i = 50.5 +/- 3.38 msec; left LR2i = 52.2 msec; right LR2c = 50.7 +/- 4.26; left LR2c = 50.6 +/- 4.07). Findings in abnormal patients differ significantly from normal, consistent with the distribution of neuropathy. CONCLUSIONS: We describe a novel, clinically applicable conduction study of laryngeal nerves. Normative electrodiagnostic values and variations of the reflex responses of the laryngeal adductor muscles in response to irritative stimulation of the laryngeal mucosa (Laryngeal Closure Reflex) are proposed. By enabling the determination of electrophysiological parameters of the superior laryngeal and recurrent laryngeal branches of cranial nerve X (CN X), this procedure, which is used as an adjunct to laryngeal electromyography, may provide earlier and more accurate information regarding the extent and grade of nerve injury. Because injury grade relates directly to prognosis, the information derived from this test may have clinical relevance in determining optimal treatment. LEVEL OF EVIDENCE: 4. Laryngoscope, 123:2202-2208, 2013.

OBJECTIVES/HYPOTHESIS: We hypothesize that the KTP laser has the potential to augment wound healing in a rat model, and this modality may serve as a therapeutic tool for the management of vocal fold fibrosis. STUDY DESIGN: Prospective, laboratory animal study. METHODS: Rats were subjected to either vocal fold injury +/- KTP laser treatment at low energy to simulate clinically relevant endpoints. In addition, cohorts were subjected to therapeutic KTP laser alone. Endpoints included the analyses of gene expression data related to the acute inflammatory response and extracellular matrix deposition and organization. RESULTS: Therapeutic KTP treatment was associated with an additive effect on inflammatory gene expression in the context of the injured rat vocal fold mucosa. A similar additive effect was observed for matrix metalloproteinase gene expression, similar to data previously reported in the dermatology literature. However, histologically, the KTP had little effect on established vocal fold fibrosis. CONCLUSIONS: These data are the first to attempt to provide mechanistic insight into the clinical utility of angiolytic lasers for vocal fold scar. Similar to previous data obtained in the skin, it appears that these effects are mediated by MMPs. LEVEL OF EVIDENCE: NA. Laryngoscope, 123:2189-2194, 2013.

BACKGROUND: The olfactory epithelium is a self-renewing tissue, able to produce new neurons as needed from stem and progenitor cells in its basal layers. In addition, there exists a mesenchymal-like stem cell (MSC) located within the underlying lamina propria. Little is known about the function of this nasal MSC, or its relationship to the olfactory lineage, but there is considerable interest in using the nasal MSC for cell-based therapies. We sought to further explore the biology of the nasal MSC by establishing neurosphere cultures from adult human nasal biopsies, and to examine the anatomic distribution of nasal MSCs. METHODS: Nasal biopsies from human patients (n = 5) were obtained from superior, middle, and inferior turbinates or septum. Tissue was cultured to obtain nasal MSCs. Cultures were analyzed by immunocytochemistry and flow cytometry, as well as for differentiation capacity. RESULTS: Although olfactory sensory neuroepithelium is restricted to superior regions in the nasal cavity, neurosphere-forming MSC cultures were, surprisingly, obtained from olfactory as well as non-olfactory regions. These MSC cultures exhibit characteristic robust neurosphere formation and express CD90, CD105, STRO-1, and nestin. Nasal MSCs were found to give rise to neuronal-like cells under differentiation conditions. CONCLUSION: The unanticipated broad anatomic distribution of nasal MSCs has implications for cell-based therapy research.

Sensory deprivation, such as developmental hearing loss, leads to an adjustment of synaptic and membrane properties throughout the central nervous system. These changes are thought to compensate for diminished sound-evoked activity. This model predicts that compensatory changes should be synergistic with one another along each functional pathway. To test this idea, we examined the excitatory thalamic drive to two types of cortical inhibitory interneurons that display differential effects in response to developmental hearing loss. The inhibitory synapses made by fast-spiking (FS) cells are weakened by hearing loss, whereas those made by low threshold-spiking (LTS) cells remain strong but display greater short-term depression (Takesian et al. 2010). Whole-cell recordings were made from FS or LTS interneurons in a thalamocortical brain slice, and medial geniculate (MG)-evoked postsynaptic potentials were analyzed. Following hearing loss, MG-evoked net excitatory potentials were smaller than normal at FS cells but larger than normal at LTS cells. Furthermore, MG-evoked excitatory potentials displayed less short-term depression at FS cells and greater short-term depression at LTS cells. Thus deprivation-induced adjustments of excitatory synapses onto inhibitory interneurons are cell-type specific and parallel the changes made by the inhibitory afferents.

Pilocytic astrocytoma, the most common childhood brain tumor, is typically associated with mitogen-activated protein kinase (MAPK) pathway alterations. Surgically inaccessible midline tumors are therapeutically challenging, showing sustained tendency for progression and often becoming a chronic disease with substantial morbidities. Here we describe whole-genome sequencing of 96 pilocytic astrocytomas, with matched RNA sequencing (n = 73), conducted by the International Cancer Genome Consortium (ICGC) PedBrain Tumor Project. We identified recurrent activating mutations in FGFR1 and PTPN11 and new NTRK2 fusion genes in non-cerebellar tumors. New BRAF-activating changes were also observed. MAPK pathway alterations affected all tumors analyzed, with no other significant mutations identified, indicating that pilocytic astrocytoma is predominantly a single-pathway disease. Notably, we identified the same FGFR1 mutations in a subset of H3F3A-mutated pediatric glioblastoma with additional alterations in the NF1 gene. Our findings thus identify new potential therapeutic targets in distinct subsets of pilocytic astrocytoma and childhood glioblastoma.