Spindle Cell Lipoma Arising from the Supraglottis: A Case Report and Review of the Literature.

Lipomas are common benign mesenchymal neoplasms. Although 13% of lipomas are found in the head and neck, only 0.6% have been reported in the larynx. Of all lipomas, the spindle cell variant is the least common. In the present study, we report a case of supraglottic spindle cell lipoma and review the literature of laryngeal spindle cell lipoma. A 35-year-old male presented with dysphagia and dyspnea and was found to have bilateral supraglottic lesions causing airway obstruction. The masses were resected endoscopically. Final pathology demonstrated mature adipocytes and spindle cells, with immunohistochemical patterns supportive of spindle cell lipoma. Spindle cell lipomas have rarely been reported in the upper airway. To our knowledge, this is the youngest patient reported to date. These lipomas are uncommon benign neoplasms and should be distinguished from aggressive mesenchymal neoplasms such as liposarcoma variants to guide appropriate conservative but curative therapy.

Ankyloglossia: Last three-years of outpatient care at a tertiary referral center.

INTRODUCTION: Ankyloglossia is an oral anomaly characterized by a shortened, thickened lingual frenulum that may cause reduced tongue mobility. However, the diagnosis and management of this condition has long been a debated topic. Given the paucity of high level evidence, management can be frustrating for both families and clinicians. Our study aims to examine differences in the management of ankyloglossia and investigate influencing factors at a single tertiary pediatric referral center. METHODS: A retrospective chart review was completed of children less than one year of age seen in the outpatient otolaryngology clinic. Billing records were searched for ICD-9 code 750.0 (ankyloglossia) between January 2, 2015 and October 9, 2017 and data extracted from the charts of those meeting inclusion criteria. RESULTS: A total of 266 charts were reviewed that met the inclusion criteria during the study period. 100 (38%) were female with a mean age of 2.9 months. In the final multivariate regression model, children seen by providers in Group 1 (providers with high rates of frenotomies) had 4.4 times the odds of having a frenotomy as those seen by a provider in Group 2 (providers with low rates of frenotomies) (p < 0.001, 95%CI: 2.2, 8.9), and male children had 2.5 times the odds of having a frenotomy as female children (p = 0.002, 95%CI: 1.4, 4.5). CONCLUSION: In this study we identify additional variables that may influence the decision to perform a frenotomy in children with ankyloglossia. The significant impact of clinician biases in the management of ankyloglossia suggests arbitrary differences in the way these patients are managed, highlighting the lack of consensus amongst otolaryngologists and the need for clear indications and diagnostic criteria.

Middle ear lipoma mimicking a congenital cholesteatoma: A case report and review of the literature.

OBJECTIVE: To describe a case of middle ear lipoma, review the current literature, and discuss the surgical approach. METHODS: Published case reports in the English literature of lipomas restricted to the middle ear were reviewed. The presentation, location, and management of the middle ear lipomas were analyzed. RESULTS: Histological examination of the resected middle ear lesion was compatible with lipoma. Review of the literature suggests middle ear lipomas are rare and involve the epitympanum. CONCLUSION: Lipomas should be included in the differential diagnosis for middle ear lesions. Adequate surgical exposure can be achieved through a transcanal approach, with particular attention to carefully elevate the tympanic membrane off the malleus, preserving the integrity of the ossicular chain.

D-Cycloserine Restores Experience-Dependent Neuroplasticity after Traumatic Brain Injury in the Developing Rat Brain.

Traumatic brain injury (TBI) in children can cause persisting cognitive and behavioral dysfunction, and inevitably raises concerns about lost potential in these injured youth. Lateral fluid percussion injury (FPI) in weanling rats pathologically affects hippocampal N-methyl-d-aspartate receptor (NMDAR)- and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-mediated glutamatergic neurotransmission subacutely within the first post-injury week. FPI to weanling rats has also been shown to impair enriched-environment (EE) induced enhancement of Morris water maze (MWM) learning and memory in adulthood. Recently, improved outcomes can be achieved using agents that enhance NMDAR function. We hypothesized that administering D-cycloserine (DCS), an NMDAR co-agonist, every 12 h (i.p.) would restore subacute glutamatergic neurotransmission and reinstate experience-dependent plasticity. Postnatal day 19 (P19) rats received either a sham or FPI. On post-injury day (PID) 1-3, animals were randomized to saline (Sal) or DCS. Firstly, immunoblotting of hippocampal NMDAR and AMPAR proteins were measured on PID4. Second, PID4 novel object recognition, an NMDAR- and hippocampal- mediated working memory task, was assessed. Third, P19 rats were placed in an EE (17 days), and MWM performance was measured, starting on PID30. On PID4, DCS restored reduced NR2A and increased GluR2 by 54%, and also restored diminished recognition memory in FPI pups. EE significantly improved MWM performance in shams, regardless of treatment. In contrast, FPI-EE-Sal animals only performed to the level of standard housed animals, whereas FPI-EE-DCS animals were comparable with sham-EE counterparts. This study shows that NMDAR agonist use during reduced glutamatergic transmission after developmental TBI can reinstate early molecular and behavioral responses that subsequently manifest in experience-dependent plasticity and rescued potential.

Elucidating molecular phenotypes caused by the SORL1 Alzheimer's disease genetic risk factor using human induced pluripotent stem cells.

Predisposition to sporadic Alzheimer's disease (SAD) involves interactions between a person's unique combination of genetic variants and the environment. The molecular effect of these variants may be subtle and difficult to analyze with standard in vitro or in vivo models. Here we used hIPSCs to examine genetic variation in the SORL1 gene and possible contributions to SAD-related phenotypes in human neurons. We found that human neurons carrying SORL1 variants associated with an increased SAD risk show a reduced response to treatment with BDNF, at the level of both SORL1 expression and APP processing. shRNA knockdown of SORL1 demonstrates that the differences in BDNF-induced APP processing between genotypes are dependent on SORL1 expression. We propose that the variation in SORL1 expression induction by BDNF is modulated by common genetic variants and can explain how genetic variation in this one locus can contribute to an individual's risk of developing SAD.

The presenilin-1 ΔE9 mutation results in reduced γ-secretase activity, but not total loss of PS1 function, in isogenic human stem cells.

Presenilin 1 (PS1) is the catalytic core of γ-secretase, which cleaves type 1 transmembrane proteins, including the amyloid precursor protein (APP). PS1 also has γ-secretase-independent functions, and dominant PS1 missense mutations are the most common cause of familial Alzheimer's disease (FAD). Whether PS1 FAD mutations are gain- or loss-of-function remains controversial, primarily because most studies have relied on overexpression in mouse and/or nonneuronal systems. We used isogenic euploid human induced pluripotent stem cell lines to generate and study an allelic series of PS1 mutations, including heterozygous null mutations and homozygous and heterozygous FAD PS1 mutations. Rigorous analysis of this allelic series in differentiated, purified neurons allowed us to resolve this controversy and to conclude that FAD PS1 mutations, expressed at normal levels in the appropriate cell type, impair γ-secretase activity but do not disrupt γ-secretase-independent functions of PS1. Thus, FAD PS1 mutations do not act as simple loss of PS1 function but instead dominantly gain an activity toxic to some, but not all, PS1 functions.

Concussive brain injury enhances fear learning and excitatory processes in the amygdala.

BACKGROUND: Mild traumatic brain injury (cerebral concussion) results in cognitive and emotional dysfunction. These injuries are a significant risk factor for the development of anxiety disorders, including posttraumatic stress disorder. However, because physically traumatic events typically occur in a highly emotional context, it is unknown whether traumatic brain injury itself is a cause of augmented fear and anxiety. METHODS: Rats were trained with one of five fear-conditioning procedures (n = 105) 2 days after concussive brain trauma. Fear learning was assessed over subsequent days and chronic changes in fear learning and memory circuitry were assessed by measuring N-methyl-D-aspartate receptor subunits and glutamic acid decarboxylase, 67 kDa isoform protein levels in the hippocampus and basolateral amygdala complex (BLA). RESULTS: Injured rats exhibited an overall increase in fear conditioning, regardless of whether fear was retrieved via discrete or contextual-spatial stimuli. Moreover, injured rats appeared to overgeneralize learned fear to both conditioned and novel stimuli. Although no gross histopathology was evident, injury resulted in a significant upregulation of excitatory N-methyl-D-aspartate receptors in the BLA. There was a trend toward decreased γ-aminobutyric acid-related inhibition (glutamic acid decarboxylase, 67 kDa isoform) in the BLA and hippocampus. CONCLUSIONS: These results suggest that mild traumatic brain injury predisposes the brain toward heightened fear learning during stressful postinjury events and provides a potential molecular mechanism by which this occurs. Furthermore, these data represent a novel rodent model that can help advance the neurobiological and therapeutic understanding of the comorbidity of posttraumatic stress disorder and traumatic brain injury.

ACAT1 gene ablation increases 24(S)-hydroxycholesterol content in the brain and ameliorates amyloid pathology in mice with AD.

Cholesterol metabolism has been implicated in the pathogenesis of several neurodegenerative diseases, including the abnormal accumulation of amyloid-beta, one of the pathological hallmarks of Alzheimer disease (AD). Acyl-CoA:cholesterol acyltransferases (ACAT1 and ACAT2) are two enzymes that convert free cholesterol to cholesteryl esters. ACAT inhibitors have recently emerged as promising drug candidates for AD therapy. However, how ACAT inhibitors act in the brain has so far remained unclear. Here we show that ACAT1 is the major functional isoenzyme in the mouse brain. ACAT1 gene ablation (A1-) in triple transgenic (i.e., 3XTg-AD) mice leads to more than 60% reduction in full-length human APPswe as well as its proteolytic fragments, and ameliorates cognitive deficits. At 4 months of age, A1- causes a 32% content increase in 24-hydroxycholesterol (24SOH), the major oxysterol in the brain. It also causes a 65% protein content decrease in HMG-CoA reductase (HMGR) and a 28% decrease in sterol synthesis rate in AD mouse brains. In hippocampal neurons, A1- causes an increase in the 24SOH synthesis rate; treating hippocampal neuronal cells with 24SOH causes rapid declines in hAPP and in HMGR protein levels. A model is provided to explain our findings: in neurons, A1- causes increases in cholesterol and 24SOH contents in the endoplasmic reticulum, which cause reductions in hAPP and HMGR protein contents and lead to amelioration of amyloid pathology. Our study supports the potential of ACAT1 as a therapeutic target for treating certain forms of AD.