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Objective: The short T2 nature of cortical bone causes it to appear similar to air on MR, forcing clinicians to rely on computed tomography imaging, with its attendant ionizing radiation exposure, to define temporal bone structures. Through the use of novel MR sequences with ultra-short echo times (UTE), short T2 structures are now able to be visualized, allowing for improved understanding of anatomical relationships., Methods: Eight patients (50% female) undergoing MR imaging of the skull base for diagnostic purposes (62.5% for vestibular schwannoma surveillance) at a tertiary care center were enrolled to evaluate the safety and efficacy of UTE imaging. CT scans were completed in 37.5% of the patients as part of their workup and used for comparison purposes. The repetition time, short echo time, and long echo time for the UTE sequence were 11, 0.032, and 2.2 msec, respectively., Results: The protocol added 6 min to the total scanning time, and all patients tolerated the sequence without issue. The ossicles, mastoid air cells, antrum, and epitympanum were able to be seen and had a high Dice similarity coefficient when compared to CT (>0.5). UTE allowed for clear delineation of all segments of the facial nerve with a signal-to-noise ratio of 35 (although the BRAVO sequences had a superior ratio of 140). Vestibular schwannomas were able to be distinguished from normal brain parenchyma., Conclusions: UTE is safe and effective for visualizing anatomic structures not normally seen on traditional MRI, potentially allowing for improved surgical planning in patients., Level of Evidence: 3 Laryngoscope, 134:4691-4696, 2024., (© 2024 The American Laryngological, Rhinological and Otological Society, Inc.)

Hypothesis: Commercially available povidone-iodine solution can eliminate biofilms and persister cells rapidly in in vivo achievable concentrations without inducing ototoxicity., Background: Chronic suppurative otitis media (CSOM) is a substantial global problem. Current treatment options often induce a temporary remission without leading to a permanent cessation of symptoms secondary to the treatments' inability to eliminate persister cells. Povidone-iodine has been shown to be able to clear biofilm and planktonic cells in in vitro assays, but there are reports of ototoxic effects limiting its clinical utility., Methods: Bacterial and biofilm growth with quantification by spectrophotomer, murine auditory brainstem response (ABR), and distortion product otoacoustic emissions, immunohistochemistry, in vivo povidone-iodine treatment of murine CSOM, persister cell assay., Results: Commercially available 10% povidone-iodine solution is able to completely eradicate multiple clinical strains of Pseudomonas aeruginosa and Staphylococcus aureus in vitro with 10 minutes of exposure. Mice that have received a transtympanic injection of 1% povidone-iodine solution did not have significantly different auditory brainstem response or distortion product otoacoustic emission results compared with the control. Mice that received a povidone-iodine scrub or 10% povidone-iodine solution had significantly worsened hearing (25- and 13-dB increase in threshold, respectively; p < 0.05). In vivo CSOM infection recurred in all mice after the completion of treatment with 10% povidone-iodine solution, and there was no improvement in the bacterial load after treatment, indicating in vivo failure of therapy., Conclusion: Povidone-iodine solution is effective at eliminating biofilm and persister cells in vitro at in vivo achievable concentrations but fails in vivo most likely because of kinetics of distribution in vivo. Even if drug distribution could be improved, the therapeutic window is likely to be too small given that the diluted solution does not have ototoxic potential, whereas while the scrub variant, which contains detergents, and the undiluted solution are ototoxic after a single treatment., Competing Interests: Conflicts of interest: P.L.S.M., L.A.B., and A.X. are inventors on patents for treatments for chronic suppurative otitis media currently owned by Stanford University., (Copyright © 2022, Otology & Neurotology, Inc.)

Objective: To report the frequency of radiographic superior semicircular canal dehiscence (SSCD) and tegmen dehiscence in patients with and without obstructive sleep apnea (OSA)., Study Design: Retrospective matched cohort study., Setting: Tertiary care center., Patients: Adults with OSA and fine-cut computed tomographic scans including the temporal bone were matched to patients without OSA by age, sex, and type of computed tomography (protocol, scanner type, slice thickness). Ears with otologic surgery or temporal bone tumors were excluded., Main Outcome Measures: Prevalence of SSCD and tegmen dehiscence assessed by two independent reviewers., Results: The average body mass index of the OSA patients was 29.2 kg/m 2 with an average apnea-hypopnea index of 36.8. The control group had an average body mass index of 26.2 kg/m 2 . Of the 352 temporal bones, 34 (9.7%) had SSCD in the OSA cohort versus 37 (10.5%) in the control group ( p > 0.05). Seven OSA patients (25.6% of those with SSCD) had bilateral SSCD versus 8 controls (27.6% of those with SSCD; p > 0.05). The majority (87.3%) of dehiscences involved the temporal lobe, with the remaining involving the superior petrosal sinus or both. Of the 352 OSA ears, 90 (25.6%) had a tegmen dehiscence versus 95 (27.0%) in the control group ( p > 0.05). Neither group had a laterality preference for SSCD or tegmen dehiscence., Conclusion: The prevalence of radiographic SSCD and tegmen dehiscences in OSA patients does not significantly differ from age- and sex-matched controls. This is in contrast to a previous case-control study finding patients with symptomatic SSCD to have higher rates of OSA. This may suggest that the effect size of OSA on SSCD prevalence may be limited despite OSA being a risk factor for elevated intracranial pressure., Competing Interests: The authors disclose no conflicts of interest., (Copyright © 2022, Otology & Neurotology, Inc.)

Objective: To report health utilization patterns and outcomes of medical and surgical management in patients with chronic suppurative otitis media (CSOM)., Study Design: Retrospective cohort., Setting: Academic otology clinic., Methods: This study included 175 patients with CSOM with a first clinic visit at our institution between March 2011 and November 2016. All patients displayed a diagnosis of CSOM by International Classification of Diseases code, had at least 1 episode of active CSOM (defined as perforation with otorrhea), and had a documented history of chronic ear infections. The mean age was 49.5 ± 1.5 years, 53% were female, and mean follow-up time was 3.5 ± 0.3 years., Results: Patients had an average of 9.5 ± 0.5 otology visits, 4.7 ± 0.4 prescriptions, and 1.7 ± 0.1 surgeries, with estimated per patient cost ranging from $3927 to $20,776. Under medical management, 69% of patients displayed recurrence of disease, with a median time to recurrence of 4 months. For tympanoplasty and tympanomastoidectomy, median time to recurrence was similar at 5 and 7 years, respectively ( P = .73). At the most recent visit, the prevalence of all patients with CSOM displaying moderate or worse sensorineural hearing loss (SNHL) was 41%., Conclusions: CSOM represents a major public health issue with high health care utilization and associated costs. Surgery is superior to medical therapy for achieving short- to medium-term inactive disease. Patients with CSOM display a high SNHL burden.

We present an unusual case of chordoma arising entirely from the lateral skull base with imaging features suggestive of a paraganglioma. Clinical history, management, histopathology, and imaging characteristics are described, including a review of gallium-dotate PET scanning somatostatinreceptor-positive tumors. We further provide a review of management options, including a summary of our approach with surgical biopsy via retrosigmoid and resection via transtemporal approaches. Based on radiologic characteristics and location, lateral skull base chordoma may arise with isolated lateral skull base involvement and has the potential to be misidentified as a glomus jugulare on initial workup., Competing Interests: The authors disclose no conflicts of interest., (Copyright © 2021, Otology & Neurotology, Inc.)

Objective: Chronic suppurative otitis media (CSOM) is characterized by a chronically draining middle ear. CSOM is typically treated with multiple courses of antibiotics or antiseptics which are successful in achieving quiescence; however, the disease is prone to relapse. Understanding why these treatment failures occur is essential., Study Design: The minimum inhibitory concentration (MIC), minimal biofilm eradication concentration, and the inhibitory zone were determined for ototopicals and ofloxacin for the laboratory strains and CSOM-derived isolates. The percentage of persister cells and bacterial biofilm formation were measured. Disease eradication was tested in a validated in-vivo model of CSOM after treatment with ofloxacin., Setting: Microbiology Laboratory., Methods: Basic science experiments were performed to measure the effectiveness of a number of compounds against CSOM bacteria in a number of distinct settings., Results: The minimal biofilm eradication concentration is higher than is physiologically achievable with commercial preparations, except for povo-iodine. Clincial isolates of CSOM have equivalent biofilm-forming ability but increased proportions of persister cells. Ofloxacin can convert to inactive disease temporarily but fails to eradicate disease in an in-vivo model., Conclusions: Higher percentages of persister cells in clinical CSOM isolates are associated with resistance to ototopicals. Current ototopicals, except povo-iodine, have limited clinical effectiveness; however, it is unknown what the maximum achievable concentration is and there are ototoxicity concerns. Fluoroquinolones, while successful in producing inactive disease in the short term, have the potential to encourage antimicrobial resistance and disease recalcitrance and do not achieve a permanent remission. Given these limitations, clinicians should consider surgery earlier or use of clinically safe concentrations of povo-iodine earlier into the treatment algorithm., Competing Interests: The authors disclose no conflicts of interest., (Copyright © 2021, Otology & Neurotology, Inc.)

Objective: To evaluate the presence of bitter taste receptors (T2Rs) in the middle ear and to examine their relationship with chronic ear infections., Study Design: Cross-sectional study., Setting: Tertiary care hospital., Methods: This study enrolled 84 patients being evaluated for otologic surgery: 40 for chronic otitis media (COM) and 44 for other surgical procedures (controls). We collected a small piece of mucosa from 14 patients for mRNA analysis and from 23 patients for immunohistochemistry. A total of 55 patients underwent a double-blind taste test to gauge sensitivity to phenylthiocarbamide, denatonium, quinine, sucrose, and sodium chloride; 47 patients gave a salivary sample for single-nucleotide polymorphism analysis of rs1376251 ( TAS2R50 ) and rs1726866 ( TAS2R38 )., Results: Bitter taste receptors were found in all samples, but the repertoire varied among patients. T2R50 was the most consistently identified receptor by mRNA analysis. Its rs1376251 allele was related to susceptibility to COM but not the expression pattern of T2R50. Ratings of bitterness intensity of phenylthiocarbamide, a ligand for T2R38, differed significantly between the COM and control groups., Conclusion: T2Rs were found within the middle ear of every patient sampled; the rs1376251 allele of TAS2R50 appears to be related to chronic ear infections. These receptors are an intriguing target for future research and possible drug targeting.

Objective: To assess the impact of reconstructive technique on the incidence of cerebrospinal fluid (CSF) leak following retrosigmoid approach to acoustic neuroma resection., Study Design: Retrospective case series., Setting: Academic medical center., Patients: A total of 1,200 patients with acoustic neuromas presented to our institution from 2005 to 2018. Of these, 196 patients underwent surgical resection via a retrosigmoid approach., Intervention: At our institution, internal auditory canal (IAC) reconstruction following a retrosigmoid approach was performed with bone wax and muscle plug or Norian hydroxyapatite bone cement from 2005 to 2013. Starting in 2014, a newer model of bone cement, Cranios hydroxyapatite, was used exclusively for reconstruction., Main Outcome Measures: Rates of CSF leak were evaluated across different methods of IAC reconstruction and types of bone cement. Patients whose leaks were attributable to the craniectomy site were excluded from analysis., Results: The postoperative CSF leak rate among patients who did not receive bone cement for IAC reconstruction was 15.6% (n.5). The leak rate amongst patients who received Norian bone cement was 6.3% (n.4). After introduction of Cranios bone cement, the total leak rate decreased to 1% (n.1). Compared with all other types of closure, Cranios had a significantly reduced rate of postoperative CSF leak (p < 0.005). The leak rate following Cranios versus Norian was also significantly reduced (p < 0.05). Leak rate was not affected by tumor size (p.0.30) or age (p.0.43)., Conclusion: CSF leak rate following acoustic neuroma resection was significantly reduced by introduction of Cranios hydroxyapatite bone cement., Competing Interests: Disclosures: The authors of this study have no conflicts of interest to disclose regarding any of the products and materials discussed in this report. The University of Pennsylvania Department of Neurosurgery received financial support from Synthes in return for internal data related to Cranios. Synthes was not involved in this study., (Copyright © 2021, Otology & Neurotology, Inc.)

Objective: To characterize postoperative electrode functionality after adult cochlear implantation; to identify rationale and risk factors for electrode deactivation., Study Design: Retrospective Chart Review., Setting: Academic Cochlear Implant Center., Subject Population: Five hundred nineteen cochlear implants in 433 adult patients over 5 years., Interventions: Unilateral or bilateral cochlear implantation., Main Outcome Measures: Rate of electrode deactivation after adult cochlear implantation., Results: One hundred twenty (27.7%) patients experienced electrode deactivation postoperatively, involving a total of 447 electrodes. The most common reasons for deactivation were bothersome nonauditory symptoms (n = 170, 38.0%), perceived benefit by patients (n = 64, 14.3%), and bothersome auditory symptoms (n = 60, 13.4%). Four hundred nineteen (93.7%) of involved electrodes remained deactivated at most recent follow-up, whereas 28 (6.3%) were able to be reactivated. Deactivation was most likely to occur within the first 4 weeks after activation (n = 90 patients,75.0%; p < 0.01). Among affected patients, the average number of electrodes deactivated was 3.44 (range 1-13; SD 2.50). Age was not associated with electrode deactivation., Conclusions: While 98% of cochlear implants had full insertions, more than a quarter of implantees may experience electrode deactivation postoperatively for a multitude of reasons, with bothersome nonauditory symptoms most prevalent. Deactivation of five or more electrodes and simultaneous deactivation of two or three electrodes seems to increase the odds of subsequent device failure. However, deactivation encompasses a wide range of issues that likely include patient factors, surgical technique, and device-specific issues. Prognosis varies greatly at the individual level and further evaluation is required to better identify the issues underlying deactivation and identify true predictors of failure., Competing Interests: The authors disclose no conflicts of interest., (Copyright © 2021, Otology & Neurotology, Inc.)

Objectives  A persistent craniopharyngeal canal (CPC) is a rare embryologic remnant that presents as a well-corticated defect of the midline sphenoid body extending from the sellar floor to the nasopharynx. Our case series aims to describe three unique presentations of this congenital anomaly and their subsequent management. Design  Retrospective review. Setting  Tertiary academic medical center. Participants  Patients who underwent endoscopic transnasal surgical repair of a CPC lesion. Main Outcome Measures  Resolution of symptoms and surgical outcomes. Results  A total of three patients were identified. The clinical presentation varied, however, all cases prompted further imaging which demonstrated a persistent CPC and associated pathologic lesion. The presentation of a persistent CPC with nasal obstruction and subsequent iatrogenic cerebrospinal fluid leak as in Case 1 demonstrates the importance of imaging in this work-up. Cases 2 and 3 in the series were representative of the larger subset of patients in the literature who present with the defect incidentally but still warrant surgical management. Nonetheless, a standard approach to diagnosis with preoperative imaging and subsequent transnasal endoscopic repair of the skull base defect was undertaken. Conclusion  The persistent CPC is a rare congenital anomaly associated with diverse pathology and careful review of preoperative radiology is critical to the management. When warranted, subsequent surgical repair and reconstruction is associated with excellent postoperative outcomes., Competing Interests: Conflict of Interest None., (© Thieme Medical Publishers.)

Objective: To evaluate factors influencing the development of nonauditory percepts and facial nerve stimulation after cochlear implant (CI) activation., Study: Retrospective cohort study., Setting: Tertiary referral center., Patients: Over the course of 5 years, 433 consecutive patients were evaluated for CI and 518 ears were implanted. Of those, 497 ears had information regarding CI activation., Interventions: Lateral wall electrodes (LWE) or perimodiolar/mid-scalar electrodes (PME) were used during implantation., Primary Outcome Measure: Nonauditory percepts and facial nerve stimulation after activation of CI., Results: Among the 497 devices, which were activated at our institution, 357 (72%) had LWE while 140 (28%) patients had a PME. Of the patients with LWE, 49 (13.7%) patients experienced some form of nonauditory percept. In comparison, 11 (9.2%) patients with a PME had some form of nonauditory percept (p < 0.05). Among the patients who had an LWE, 33 (9.2%) patients had facial nerve stimulation compared with 6 (4.3%) patients with PME (p < 0.05). Additionally, there were 11 (2.2%) patients with incomplete insertion of the electrode who had a significant increase (p < 0.05) in facial nerve stimulation. The mean number of electrodes requiring programming modification to control symptoms was 2.9., Conclusions: The use of LWE and incomplete insertions significantly increase the rate of nonauditory percepts and FNS after activation of CIs. Otic capsule anomalies are an independent risk factor for both.

Introduction: Mucoepidermoid carcinoma (MEC) of the upper aerodigestive tract (UADT) is an uncommon malignancy, with limited literature available on its clinical and pathologic characteristics. Here, we describe the behavior of MEC of the UADT including pathologic characteristics and predictors of nodal metastasis., Methods: Retrospective cohort study of patients with MEC of the UADT treated at an academic medical center from January 2008 to May 2018. Data was collected about demographics and tumor characteristics including clinical and histological data. The two-tailed Student t test and χ2 analysis were performed to assess for predictors of nodal metastasis., Results: We identified 44 patients with minor salivary gland MEC of the oral cavity (OC) and oropharynx (OP). All patients were treated with primary site surgery. The primary site was the OC in 25 patients (57%) and OP in 19 (43%). Low-grade histology was seen in 27 specimens (61.4%), intermediate histology in 9 specimens (20.5%), and high-grade histology in 8 specimens (18.2%). Perineural invasion was noted in 10 specimens (22.7%). Neck dissection was performed in 17 patients (39%), with pathologically positive nodes found in 9 (20.5%). Notably, 5 of the 9 positive nodal specimens were found in clinically node-negative necks. Pathologically positive cervical lymph nodes were significantly associated with the OP as the primary site (p = 0.0005), perineural invasion (p = 0.012), lymphovascular invasion (p < 0.001), and high-grade histology (p = 0.004) in the primary specimen., Discussion: MEC of the UADT is an uncommon malignancy. Our findings suggest elective neck dissection should be considered with perineural and lymphovascular invasion, high-grade tumor, and the OP as the primary site., (© 2020 S. Karger AG, Basel.)

Objective: To review current literature and experience with glomangiomas, or true glomus tumors of the middle ear and mastoid as well asto report on the exceptionally rare case of a glomangiomastemming from the middle ear space with multiple recurrences., Methods: Review of existing world literature and description of personal experience with rare cases of a glomangioma of the middle ear and mastoid., Results: Review of existing literature revealed two cases of patients presenting with tinnitus and hearing loss refractory to medical management. Both patients were ultimately diagnosed with glomangioma on histopathology. Complete surgical excision is thought to be curative., Patient: A 36-year-old woman presented with a rare case of a glomangioma of the middle ear presenting with unilateral hearing loss. She was noted to have a mass behind the tympanic membrane. Imaging revealed a diffuse mass filling the mastoid air cells. Imaging characteristics and histology were consistent with a glomangioma., Intervention: Initial resection via mastoidectomy using a postauricular approach. The tympanic membrane was reconstructed with temporalis tissue. Follow-up revision tympanomastoidectomy was performed upon recurrence of disease. The chorda tympani were sacrificed due to tumor involvement. The incus and head of the malleus were removed to gain better access to the tumor. The ossicular chain was reconstructed with a Goldenberg Total Ossicular Prosthesis., Main Outcome Measure: Recurrence of disease., Follow-Up: In the 67 months since her most recent surgery, there has been no evidence of recurrence by CT or physical exam., Conclusion: Glomangioma of the middle ear represents an exceptionally rare entity that can present in a similar fashion to a paraganglioma., Competing Interests: The authors have no funding, financial relationships, or conflicts of interest to disclose., (© 2019 The Authors.)

Objective: To examine quality of life changes for patients with vestibular schwannoma (VS) undergoing observation or stereotactic radiosurgery (SRS)., Study Design: Retrospective review., Setting: Academic medical center., Patients: Patients with VS who underwent observation or SRS and had at least two audiograms and Penn Acoustic Neuroma Quality of Life (PANQOL) surveys, a quality of life survey for patients with VS., Interventions: SRS or observation., Main Outcome Measures: Pure-tone average (PTA), speech discrimination score (SDS), PANQOL score; controlling for tumor size, baseline hearing, and other factors., Results: One hundred twenty-three patients met inclusion criteria: 89 underwent observation and 34 SRS. There was no significant difference in the rate of decline measured by PTA (PTA worsened at a rate of 0.25 dB/yr more in the observation group compared with the SRS group, p = 0.77) and SDS (SDS worsened at a rate of 2.1%/yr more in the SRS group compared with the observation group, p = 0.82). Kaplan-Meier analysis demonstrated the SRS group had a higher probability to progress to class D hearing over observation (hazard ratio 7.1, p = 0.005). The rate of change of the SRS PANQOL scores was significantly improved in the total (p = 0.005) and hearing (p = 0.04) domain score compared with observation. However, both groups regress to a similar PANQOL total and hearing domain score over time., Conclusion: PANQOL scores were higher at baseline in the observation group than in the SRS group. However, over time, PANQOL scores in the observation group decreased while PANQOL scores in the SRS group increased, resulting in PANQOL scores that were equivalent by the end of follow-up.

Aminoglycoside antibiotics have a long history of use in the control of gram-negative bacterial infections, but their systemic use has been complicated by known ototoxicity and nephrotoxicity. Because of the utility of these medications in patients with frequent pulmonary infections, there has been a move towards the use of inhaled agents, in particular tobramycin, due to a lower rate of systemic complications. Inhaled tobramycin is generally consider to be safe from otologic complications, with only two previous reports of ototoxicity, both in patients who had underlying chronic renal disease. Here we present the first case of a patient developing isolated vestibular toxicity, without associated hearing loss or evidence of renal insufficiency, in a patient receiving inhaled tobramycin. This is an extremely rare complication of an inhaled aminoglycoside and underscores the importance of careful monitoring despite perceived safety., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objectives/hypothesis: Currently, due to the rarity of pathology, there are limited data surrounding outcomes of pediatric skull base surgery. Traditionally, surgeons have proceeded with caution when electing endonasal endoscopic transsellar/transplanum approaches to the skull base in pediatric patients due to poor sphenoid pneumatization. In this study, we review outcomes of endoscopic pediatric skull base surgery based on sphenoid pneumatization patterns., Study Design: Retrospective chart review., Methods: A review of all cases of pediatric (age < 18 years) craniopharyngioma managed via an endoscopic endonasal approach at a tertiary academic medical center., Results: A total of 27 patients were included in the analysis. The median age was 8 years. Nineteen (70%) patients were male. Presellar, sellar/postsellar, and conchal sphenoid pneumatizations were found in 6, 11, and 10 patients, respectively. There was no significant association between sphenoid pneumatization pattern and extent of resection (gross vs. subtotal, P = .414), postoperative cerebrospinal fluid (CSF) leak (P = .450), intraoperative estimated blood loss (P = .098), total operative time (P = .540), and length of stay (P = .336). On multivariate analysis, after accounting for age, sex, preoperative cranial nerve involvement, and cavernous sinus invasion, there remained no significant association between sphenoid pneumatization pattern and extent of resection (P = .999) and postoperative CSF leak (P = .959)., Conclusions: Sphenoid pneumatization pattern does not appear to affect outcomes in endoscopic skull base surgery in the pediatric population. Importantly, lack of sphenoid pneumatization does not impede gross total resection or increase complications. Thorough knowledge of the anatomy during the endoscopic approach is critical to optimize outcomes., Level of Evidence: 4 Laryngoscope, 129:832-836, 2019., (© 2018 The American Laryngological, Rhinological and Otological Society, Inc.)

Background/aims: To review the existing literature on pigmented villonodular synovitis (PVNS) of the temporomandibular joint (TMJ) and report a rare case of PVNS of the TMJ presenting with unilateral hearing loss., Methods: Review of the existing literature and a description of personal experience with PVNS of the TMJ presenting with unilateral hearing loss., Results: Review of the existing literature revealed 76 reported cases of PVNS of the TMJ. The most common presenting symptom was of a slowly enlarging mass or swelling of the preauricular area, with dysfunctional TMJ also frequently reported. All patients underwent surgical excision with some pursuing radiation as adjuvant therapy. Presented Patient: A 46-year-old man presented with several months of unilateral subjective hearing loss and aural fullness. Imaging revealed a mass centered along the superior TMJ with expansion through the squamous temporal bone and extra-axial intracranial extension into the middle cranial fossa. Imaging characteristics and fine-needle aspiration biopsy were consistent with PVNS., Intervention: The patient underwent near-total excision of the mass via frontotemporal craniectomy and lateral temporal bone resection., Follow-Up: At the 16-month follow-up there was no evidence of disease recurrence., Conclusion: PVNS of the TMJ represents a rare entity that can present with a variety of symptoms including unilateral hearing loss., (© 2019 S. Karger AG, Basel.)

Hematology and serum chemistry reference intervals have been previously established for the endangered Hawaiian monk seal ( Neomonachus schauinslandi) as an imperative measure for health assessments. Monitoring the health of the wild population depends upon reference intervals that are context specific; hence we developed reference intervals from fresh samples, as opposed to frozen, from wild monk seals. This study builds on the number of parameters from previous efforts by using samples collected between 2004 and 2015 from wild monk seals. Blood samples were analyzed by a single veterinary diagnostic laboratory within 24 hr of collection from apparently healthy, wild seals during research activities. Reference intervals were determined based on the analytical steps outlined by the American Society for Veterinary Clinical Pathology. These comprehensive hematology and serum chemistry reference intervals enable more consistent and systematic interpretation of results, which will guide individual and population-level health assessment and decision-making research and recovery activities.

Biochemical and genetic evidence implicate soluble oligomeric amyloid-β (Aβo) in triggering Alzheimer's disease (AD) pathophysiology. Moreover, constitutive deletion of the Aβo-binding cellular prion protein (PrP C ) prevents development of memory deficits in APP swe /PS1ΔE9 mice, a model of familial AD. Here, we define the role of PrP C to rescue or halt established AD endophenotypes in a therapeutic disease-modifying time window after symptom onset. Deletion of Prnp at either 12 or 16 months of age fully reverses hippocampal synapse loss and completely rescues preexisting behavioral deficits by 17 months. In contrast, but consistent with a neuronal function for Aβo/PrP C signaling, plaque density, microgliosis, and astrocytosis are not altered. Degeneration of catecholaminergic neurons remains unchanged by PrP C reduction after disease onset. These results define the potential of targeting PrP C as a disease-modifying therapy for certain AD-related phenotypes after disease onset. SIGNIFICANCE STATEMENT The study presented here further elucidates our understanding of the soluble oligomeric amyloid-β-Aβo-binding cellular prion protein (PrP C ) signaling pathway in a familial form of Alzheimer's disease (AD) by implicating PrP C as a potential therapeutic target for AD. In particular, genetic deletion of Prnp rescued several familial AD (FAD)-associated phenotypes after disease onset in a mouse model of FAD. This study underscores the therapeutic potential of PrP C deletion given that patients already present symptoms at the time of diagnosis., (Copyright © 2017 the authors 0270-6474/17/379207-15$15.00/0.)

Progranulin (PGRN) is implicated in Alzheimer's disease (AD) as well as frontotemporal lobar degeneration. Genetic studies demonstrate an association of the common GRN rs5848 variant that results in reduced PGRN levels with increased risk for AD. However, the mechanisms by which PGRN reduction from the GRN AD risk variant or mutation exacerbates AD pathophysiology remain ill defined. Here, we show that the GRN AD risk variant has no significant effects on florbetapir positron emission tomographic amyloid imaging and cerebrospinal fluid (CSF) Aβ levels, whereas it is associated with increased CSF tau levels in human subjects of the Alzheimer's disease neuroimaging initiative studies. Consistent with the human data, subsequent analyses using the APPswe/PS1ΔE9 (APP/PS1) mouse model of cerebral amyloidosis show that PGRN deficiency has no exacerbating effects on Aβ pathology. In contrast and unexpectedly, PGRN deficiency significantly reduces diffuse Aβ plaque growth in these APP/PS1 mice. This protective effect is due, at least in part, to enhanced microglial Aβ phagocytosis caused by PGRN deficiency-induced expression of TYROBP network genes (TNG) including an AD risk factor Trem2. PGRN-deficient APP/PS1 mice also exhibit less severe axonal dystrophy and partially improved behavior phenotypes. While PGRN deficiency reduces these amyloidosis-related phenotypes, other neuronal injury mechanisms are increased by loss of PGRN, revealing a multidimensional interaction of GRN with AD. For example, C1q complement deposition at synapses is enhanced in APP/PS1 mice lacking PGRN. Moreover, PGRN deficiency increases tau AT8 and AT180 pathologies in human P301L tau-expressing mice. These human and rodent data suggest that global PGRN reduction induces microglial TNG expression and increases AD risk by exacerbating neuronal injury and tau pathology, rather than by accelerating Aβ pathology.

Alzheimer's disease-related phenotypes in mice can be rescued by blockade of either cellular prion protein or metabotropic glutamate receptor 5. We sought genetic and biochemical evidence that these proteins function cooperatively as an obligate complex in the brain. We show that cellular prion protein associates via transmembrane metabotropic glutamate receptor 5 with the intracellular protein mediators Homer1b/c, calcium/calmodulin-dependent protein kinase II, and the Alzheimer's disease risk gene product protein tyrosine kinase 2 beta. Coupling of cellular prion protein to these intracellular proteins is modified by soluble amyloid-β oligomers, by mouse brain Alzheimer's disease transgenes or by human Alzheimer's disease pathology. Amyloid-β oligomer-triggered phosphorylation of intracellular protein mediators and impairment of synaptic plasticity in vitro requires Prnp-Grm5 genetic interaction, being absent in transheterozygous loss-of-function, but present in either single heterozygote. Importantly, genetic coupling between Prnp and Grm5 is also responsible for signalling, for survival and for synapse loss in Alzheimer's disease transgenic model mice. Thus, the interaction between metabotropic glutamate receptor 5 and cellular prion protein has a central role in Alzheimer's disease pathogenesis, and the complex is a potential target for disease-modifying intervention., (© The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Alzheimer disease (AD) is characterized by amyloid-β accumulation, with soluble oligomers (Aβo) being the most synaptotoxic. However, the multivalent and unstable nature of Aβo limits molecular characterization and hinders research reproducibility. Here, we characterized multiple Aβo forms throughout the life span of various AD mice and in post-mortem human brain. Aβo exists in several populations, where prion protein (PrP(C))-interacting Aβo is a high molecular weight Aβ assembly present in multiple mice and humans with AD. Levels of PrP(C)-interacting Aβo match closely with mouse memory and are equal or superior to other Aβ measures in predicting behavioral impairment. However, Aβo metrics vary considerably between mouse strains. Deleting PrP(C) expression in mice with relatively low PrP(C)-interacting Aβo (Tg2576) results in partial rescue of cognitive performance as opposed to complete recovery in animals with a high percentage of PrP(C)-interacting Aβo (APP/PSEN1). These findings highlight the relative contributions and interplay of Aβo forms in AD., (© 2015 by The American Society for Biochemistry and Molecular Biology, Inc.)

Objective: Currently no effective disease-modifying agents exist for the treatment of Alzheimer disease (AD). The Fyn tyrosine kinase is implicated in AD pathology triggered by amyloid-ß oligomers (Aßo) and propagated by Tau. Thus, Fyn inhibition may prevent or delay disease progression. Here, we sought to repurpose the Src family kinase inhibitor oncology compound, AZD0530, for AD., Methods: The pharmacokinetics and distribution of AZD0530 were evaluated in mice. Inhibition of Aßo signaling to Fyn, Pyk2, and Glu receptors by AZD0530 was tested by brain slice assays. After AZD0530 or vehicle treatment of wild-type and AD transgenic mice, memory was assessed by Morris water maze and novel object recognition. For these cohorts, amyloid precursor protein (APP) metabolism, synaptic markers (SV2 and PSD-95), and targets of Fyn (Pyk2 and Tau) were studied by immunohistochemistry and by immunoblotting., Results: AZD0530 potently inhibits Fyn and prevents both Aßo-induced Fyn signaling and downstream phosphorylation of the AD risk gene product Pyk2, and of NR2B Glu receptors in brain slices. After 4 weeks of treatment, AZD0530 dosing of APP/PS1 transgenic mice fully rescues spatial memory deficits and synaptic depletion, without altering APP or Aß metabolism. AZD0530 treatment also reduces microglial activation in APP/PS1 mice, and rescues Tau phosphorylation and deposition abnormalities in APP/PS1/Tau transgenic mice. There is no evidence of AZD0530 chronic toxicity., Interpretation: Targeting Fyn can reverse memory deficits found in AD mouse models, and rescue synapse density loss characteristic of the disease. Thus, AZD0530 is a promising candidate to test as a potential therapy for AD., (© 2015 American Neurological Association.)

Introduction: Recent studies have shown that several strains of transgenic Alzheimer's disease (AD) mice overexpressing the amyloid precursor protein (APP) have cortical hyperexcitability, and their results have suggested that this aberrant network activity may be a mechanism by which amyloid-β (Aβ) causes more widespread neuronal dysfunction. Specific anticonvulsant therapy reverses memory impairments in various transgenic mouse strains, but it is not known whether reduction of epileptiform activity might serve as a surrogate marker of drug efficacy for memory improvement in AD mouse models., Methods: Transgenic AD mice (APP/PS1 and 3xTg-AD) were chronically implanted with dural electroencephalography electrodes, and epileptiform activity was correlated with spatial memory function and transgene-specific pathology. The antiepileptic drugs ethosuximide and brivaracetam were tested for their ability to suppress epileptiform activity and to reverse memory impairments and synapse loss in APP/PS1 mice., Results: We report that in two transgenic mouse models of AD (APP/PS1 and 3xTg-AD), the presence of spike-wave discharges (SWDs) correlated with impairments in spatial memory. Both ethosuximide and brivaracetam reduce mouse SWDs, but only brivaracetam reverses memory impairments in APP/PS1 mice., Conclusions: Our data confirm an intriguing therapeutic role of anticonvulsant drugs targeting synaptic vesicle protein 2A across AD mouse models. Chronic ethosuximide dosing did not reverse spatial memory impairments in APP/PS1 mice, despite reduction of SWDs. Our data indicate that SWDs are not a reliable surrogate marker of appropriate target engagement for reversal of memory dysfunction in APP/PS1 mice.

Introduction: Despite significant progress, a disease-modifying therapy for Alzheimer's disease (AD) has not yet been developed. Recent findings implicate soluble oligomeric amyloid beta as the most relevant protein conformation in AD pathogenesis. We recently described a signaling cascade whereby oligomeric amyloid beta binds to cellular prion protein on the neuronal cell surface, activating intracellular Fyn kinase to mediate synaptotoxicity. Fyn kinase has been implicated in AD pathophysiology both in in vitro models and in human subjects, and is a promising new therapeutic target for AD. Herein, we present a Phase Ib trial of the repurposed investigational drug AZD0530, a Src family kinase inhibitor specific for Fyn and Src kinase, for the treatment of patients with mild-to-moderate AD., Methods: The study was a 4-week Phase Ib multiple ascending dose, randomized, double-blind, placebo-controlled trial of AZD0530 in AD patients with Mini-Mental State Examination (MMSE) scores ranging from 16 to 26. A total of 24 subjects were recruited in three sequential groups, with each randomized to receive oral AZD0530 at doses of 50 mg, 100 mg, 125 mg, or placebo daily for 4 weeks. The drug:placebo ratio was 3:1. Primary endpoints were safety, tolerability, and cerebrospinal fluid (CSF) penetration of AZD0530. Secondary endpoints included changes in clinical efficacy measures (Alzheimer's Disease Assessment Scale - cognitive subscale, MMSE, Alzheimer's Disease Cooperative Study - Activities of Daily Living Inventory, Neuropsychiatric Inventory, and Clinical Dementia Rating Scale - Sum of Boxes) and regional cerebral glucose metabolism measured by fluorodeoxyglucose positron emission tomography., Results: AZD0530 was generally safe and well tolerated across doses. One subject receiving 125 mg of AZD0530 was discontinued from the study due to the development of congestive heart failure and atypical pneumonia, which were considered possibly related to the study drug. Plasma/CSF ratio of AZD0530 was 0.4. The 100 mg and 125 mg doses achieved CSF drug levels corresponding to brain levels that rescued memory deficits in transgenic mouse models. One-month treatment with AZD0530 had no significant effect on clinical efficacy measures or regional cerebral glucose metabolism., Conclusions: AZD0530 is reasonably safe and well tolerated in patients with mild-to-moderate AD, achieving substantial central nervous system penetration with oral dosing at 100-125 mg. Targeting Fyn kinase may be a promising therapeutic approach in AD, and a larger Phase IIa clinical trial of AZD0530 for the treatment of patients with AD has recently launched., Trial Registration: ClinicalTrials.gov: NCT01864655. Registered 12 June 2014.

Soluble amyloid-β oligomers (Aβo) trigger Alzheimer's disease (AD) pathophysiology and bind with high affinity to cellular prion protein (PrP(C)). At the postsynaptic density (PSD), extracellular Aβo bound to lipid-anchored PrP(C) activates intracellular Fyn kinase to disrupt synapses. Here, we screened transmembrane PSD proteins heterologously for the ability to couple Aβo-PrP(C) with Fyn. Only coexpression of the metabotropic glutamate receptor, mGluR5, allowed PrP(C)-bound Aβo to activate Fyn. PrP(C) and mGluR5 interact physically, and cytoplasmic Fyn forms a complex with mGluR5. Aβo-PrP(C) generates mGluR5-mediated increases of intracellular calcium in Xenopus oocytes and in neurons, and the latter is also driven by human AD brain extracts. In addition, signaling by Aβo-PrP(C)-mGluR5 complexes mediates eEF2 phosphorylation and dendritic spine loss. For mice expressing familial AD transgenes, mGluR5 antagonism reverses deficits in learning, memory, and synapse density. Thus, Aβo-PrP(C) complexes at the neuronal surface activate mGluR5 to disrupt neuronal function., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Alzheimer's disease (AD) is a progressive neurodegenerative dementia characterized by amyloid plaque accumulation, synapse/dendrite loss, and cognitive impairment. Transgenic mice expressing mutant forms of amyloid-β precursor protein (AβPP) and presenilin-1 (PS1) recapitulate several aspects of this disease and provide a useful model system for studying elements of AD progression. AβPP/PS1 mice have been previously shown to exhibit behavioral deficits and amyloid plaque deposition between 4-9 months of age. We crossed AβPP/PS1 animals with mice of a mixed genetic background (C57BL/6 × 129/SvJ) and investigated the development of AD-like features in the resulting outcrossed mice. The onset of memory-based behavioral impairment is delayed considerably in outcrossed AβPP/PS1 mice relative to inbred mice on a C57BL/6 background. While inbred AβPP/PS1 mice develop deficits in radial-arm water maze performance and novel object recognition as early as 8 months, outcrossed AβPP/PS1 mice do not display defects until 18 months. Within the forebrain, we find that inbred AβPP/PS1 mice have significantly higher amyloid plaque burden at 12 months than outcrossed AβPP/PS1 mice of the same age. Surprisingly, inbred AβPP/PS1 mice at 8 months have low plaque burden, suggesting that plaque burden alone cannot explain the accompanying behavioral deficits. Analysis of AβPP processing revealed that elevated levels of soluble Aβ correlate with the degree of behavioral impairment in both strains. Taken together, these findings suggest that animal behavior, amyloid plaque deposition, and AβPP processing are sensitive to genetic differences between mouse strains., (Copyright © 2012 Wiley Periodicals, Inc.)

Mycobacterium avium complex infection resulted in a granuloma that developed at the base of the left ear in a cat. The lesion caused vestibular dysfunction and facial palsy on the left side and protruded into the oral cavity on that side. The cat was treated successfully, with resolution of the lesion and elimination of the organism, by use of combined administration of clofazimine and doxycycline. Adverse effects of the clofazimine treatment included temporary reddish-orange discoloration of the cat's skin and mucous membranes.

This study describes the use of a newly constructed set of primers that amplifies an 85-base pair (bp) segment of Borrelia burgdorferi chromosomal DNA. This 85-bp product is not produced when other Borrelia species, Leptospira, or other bacteria are subjected to polymerase chain reaction (PCR). We also describe a rapid method of optimizing the amplification of B. burgdorferi DNA from canine ethylenediaminetetraacetic acid-treated blood and urine samples that circumvents some of the problems encountered due to low number of spirochetes in clinical specimens and that removes inhibiting substances, which improves the PCR diagnosis of canine Lyme borreliosis.

Administration of tetracycline was believed to be associated with an adverse drug reaction in a cat. Clinical signs consisted of anorexia, ptyalism, and signs of depression. The most noticeable biochemical abnormality was a markedly high serum alanine transaminase activity. Treatment consisted of vitamin E and selenium injections and feeding via a gastrostomy tube. Abnormalities noticed on histologic examination of hepatic tissue were centrilobular fibrosis, mild diffuse cholangiohepatitis, and mild hepatic lipidosis. The lipidosis was believed to have resulted from tetracycline administration, whereas the more chronic lesions (hepatic fibrosis and mild cholangiohepatitis) were believed to have resulted from preexisting, subclinical hepatic disease. Because serum alanine transaminase activity returned to reference ranges and the anorexia and ptyalism resolved with cessation of tetracycline administration, these abnormalities were believed to have represented an adverse drug reaction. Treatment of the cat with vitamin E and selenium was instituted on the basis of reported preventive and therapeutic effects in albino rats with tetracycline-induced hepatic lesions. Whether these compounds had any role in accelerating clinical recovery in this cat is uncertain.