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Metal ions have important roles in supporting the catalytic activity of DNA-regulating enzymes such as topoisomerases (topos). Bacterial type II topos, gyrases and topo IV, are primary drug targets for fluoroquinolones, a class of clinically relevant antibacterials requiring metal ions for efficient drug binding. While the presence of metal ions in topos has been elucidated in biochemical studies, accurate location and assignment of metal ions in structural studies have historically posed significant challenges. Recent advances in X-ray crystallography address these limitations by extending the experimental capabilities into the long-wavelength range, exploiting the anomalous contrast from light elements of biological relevance. This breakthrough enables us to confirm experimentally the locations of Mg 2+ in the fluoroquinolone-stabilized Streptococcus pneumoniae topo IV complex. Moreover, we can unambiguously identify the presence of K + and Cl - ions in the complex with one pair of K + ions functioning as an additional intersubunit bridge. Overall, our data extend current knowledge on the functional and structural roles of metal ions in type II topos., Competing Interests: Competing interests statement:The authors declare no competing interest.

Circulating levels of the soluble ligand-binding ectodomain of the LDL receptor (sLDLR) that is proteolytically cleaved from the cell surface have been shown to correlate with plasma triglycerides, but the lipid and lipoprotein effects of longitudinal changes in sLDLR have not been examined. We sought to assess associations between changes in sLDLR and detailed lipoprotein measurements between baseline and 6 months in participants in the DIETFITS (Diet Intervention Examining The Factors Interacting with Treatment Success) weight loss trial who were randomly assigned to the low-fat (n = 225) or low-carbohydrate (n = 236) diet arms. sLDLR was assayed using a proteomic procedure, lipids and apoprotein (apo) B and apoAI were measured by standard assays, and lipoprotein particle subfractions were quantified by ion mobility methodology. Changes in sLDLR were significantly positively associated with changes in plasma cholesterol, triglycerides, apoB, large-sized and medium-sized VLDL, and small and very small LDL, and inversely with changes in large LDL and HDL. The lipoprotein subfraction associations with sLDLR were independent of age, sex, diet, and BMI, but all except for large LDL were reduced to insignificance when adjusted for triglyceride change. Principal component analysis identified three independent clusters of changes in lipoprotein subfractions that accounted for 78% of their total variance. Change in sLDLR was most strongly correlated with change in the principal component that was loaded positively with large VLDL and small and very small LDL and negatively with large LDL and HDL. In conclusion, sLDLR is a component of a cluster of lipids and lipoproteins that are characteristic of atherogenic dyslipidemia., Competing Interests: Conflict of interest R. M. K., research funding from Quest Diagnostics, royalties from patent on ion mobility methodology for lipoprotein analysis. All other authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Herein, we describe the discovery and optimization of a novel series that inhibits bacterial DNA gyrase and topoisomerase IV via binding to, and stabilization of, DNA cleavage complexes. Optimization of this series led to the identification of compound 25 , which has potent activity against Gram-positive bacteria, a favorable in vitro safety profile, and excellent in vivo pharmacokinetic properties. Compound 25 was found to be efficacious against fluoroquinolone-sensitive Staphylococcus aureus infection in a mouse thigh model at lower doses than moxifloxacin. An X-ray crystal structure of the ternary complex formed by topoisomerase IV from Klebsiella pneumoniae , compound 25 , and cleaved DNA indicates that this compound does not engage in a water-metal ion bridge interaction and forms no direct contacts with residues in the quinolone resistance determining region (QRDR). This suggests a structural basis for the reduced impact of QRDR mutations on antibacterial activity of 25 compared to fluoroquinolones.

Objectives: Recent technological advances have led to the capability of performing high resolution imaging of the tympanic membrane. Smartphone technologies and applications have provided the opportunity to capture digital images and easily share them. The smartphone otoscope device was developed as a simple system that can convert a smartphone into a digital otoscope. This device has the prospective ability to improve physician-patient communication and assist with the diagnosis and management of ear disease. Our objective was to evaluate the feasibility and physician/parental satisfaction using the Cellscope® smartphone attachment for at home tympanostomy tube monitoring., Methods: Children between 6 months and 15 years of age at an urban tertiary children's hospital that were scheduled for bilateral tympanostomy tube insertion or underwent bilateral tympanostomy tube surgery were prospectively enrolled in the study. Comparisons were made between parental home-recorded videos and findings during in-office otoscopy. Two independent otolaryngologists reviewed the videos and concordance between inter-rater agreements was calculated. Acceptability and use questionnaires were administered to physicians and parents., Results: There was good intra-rater agreement between traditional otoscopy and video-otoscopy for tube extruding, tube blocked and tube extruded with at least 80% agreement ( P  < .05) and excellent inter-rater agreement between physicians for nearly all tube variables ( P  < .0001) There was a high degree of satisfaction with this mode of surveillance. Parents and physicians agreed that the CellScope® smartphone was easy to use, helpful with the occurrence of acute events, and appeared to improve quality of care., Conclusions: The CellScope® smartphone is feasible for use in tympanostomy tube surveillance. Use of the device may allow otolaryngologists to easily follow a child's tympanostomy tube remotely over time and offer greater parental satisfaction.

Objectives: A previous study demonstrated low rates of high-frequency hearing loss and noise exposure among Asian Americans (AAs). This study examined the prevalence of tinnitus and associated factors among AAs using the first nationally representative sample of AAs., Study Design: Cross-sectional analysis of a national health survey., Methods: We analyzed data from the 2011 to 2012 National Health and Nutritional Examination Survey, during which 3,669 participants aged 20 to 69 years completed questionnaires on tinnitus (AA participants, n = 530). Tinnitus was defined as bothersome ringing lasting 5 minutes or more in the past 12 months. Prevalence of any tinnitus in the past 12 months was calculated incorporating sampling weights. Logistic regression was used to examine the associations with relevant factors., Results: The prevalence of any tinnitus was 6.6% (95% confidence interval [CI]: 4.5-8.6) among AAs, significantly lower than the prevalence among the overall population at 16.5% (95% CI: 14.3-18.8]. After adjusting for audiometric hearing loss and demographics, AAs were less likely to report any tinnitus than whites (odds ratio [OR] = 0.43 [95% CI: 0.24-0.75]), blacks (OR = 0.60 [95% CI: 0.37-0.95]), and Hispanics (OR = 0.60 [95% CI: 0.45-0.78]). Rates of tinnitus were not different from whites or blacks once comorbidities, noise exposure, and depression were taken into account. Among AAs, reporting exposure to work-related noise (OR = 2.92 [95% CI: 1.15-7.41]) and having a major depressive disorder (OR = 6.45 [95% CI: 1.15-36.12]) were significant factors associated with tinnitus in a multivariate model., Conclusions: The prevalence of tinnitus is significantly lower among AAs in comparison to other racial groups. Noise exposure and depression were significant factors associated with tinnitus among AAs., Level of Evidence: 2b Laryngoscope, 2020., (© 2020 The American Laryngological, Rhinological and Otological Society, Inc.)

Since their discovery over 5 decades ago, quinolone antibiotics have found enormous success as broad spectrum agents that exert their activity through dual inhibition of bacterial DNA gyrase and topoisomerase IV. Increasing rates of resistance, driven largely by target-based mutations in the GyrA/ParC quinolone resistance determining region, have eroded the utility and threaten the future use of this vital class of antibiotics. Herein we describe the discovery and optimization of a series of 4-(aminomethyl)quinolin-2(1 H )-ones, exemplified by 34 , that inhibit bacterial DNA gyrase and topoisomerase IV and display potent activity against ciprofloxacin-resistant Gram-negative pathogens. X-ray crystallography reveals that 34 occupies the classical quinolone binding site in the topoisomerase IV-DNA cleavage complex but does not form significant contacts with residues in the quinolone resistance determining region.

Trauma-focused, evidence-based psychotherapies (TF-EBPs) for posttraumatic stress disorder (PTSD) have been widely promoted in the Veterans Health Administration to provide access to state-of-the-art treatments, but dropout rates may affect the impact of TF-EBPs. The current study summarizes findings from a program evaluation of 67 veterans assigned to trauma-focused treatment in a Veterans Affairs outpatient PTSD clinic. Outcomes of interest include attendance rates, dropout rates and patterns, treatment paths, changes in self-reported symptoms, and clinician ratings. Nine veterans (13.4%) did not attend a first session and 15 (22.4%) dropped out before session 4. Twenty-three (33.8%) received either a modified version of the TF-EBP or switched to a different treatment. Only 11 (16.4%) completed the assigned TF-EBP, but 10 of those 11 (90.9%) were rated by their therapist as improved. These results align with previous research documenting high dropout rates from PTSD treatment in veterans and substantial improvements for those who complete TF-EBPs. Future study of methods to enhance retention in TF-EBP treatments is needed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Background/aims: Children with congenital cochleovestibular abnormalities associated with profound hearing loss have few treatment options if cochlear implantation does not yield benefit. An alternative is the auditory brainstem implant (ABI). Regulatory authority device approvals currently include a structured benefit-risk assessment. Such an assessment, for regulatory purposes or to guide clinical decision making, has not been published, to our knowledge, for the ABI and may lead to the design of a research program that incorporates regulatory authority, family, and professional input., Methods: Much structured benefit-risk research has been conducted in the context of drug trials; here we apply this approach to device studies. A qualitative framework organized benefit (speech recognition, parent self-report measures) and risk (surgery- and device-related) information to guide the selection of candidates thought to have potential benefit from ABI., Results: Children with cochleovestibular anatomical abnormalities are challenging for appropriate assessment of candidacy for a cochlear implant or an ABI. While the research is still preliminary, children with an ABI appear to slowly obtain benefit over time. A team of professionals, including audiological, occupational, and educational therapy, affords maximum opportunity for benefit., Conclusions: Pediatric patients who have abnormal anatomy and are candidates for an implantable auditory prosthetic require an individualized, multisystems review. The qualitative benefit-risk assessment used here to characterize the condition, the medical need, potential benefits, risks, and risk management strategies has revealed the complex factors involved. After implantation, continued team support for the family during extensive postimplant therapy is needed to develop maximum auditory skill benefit.

Importance: Problems with speech in patients with facial paralysis are frequently noted by both clinicians and the patients themselves, but limited research exists describing how facial paralysis affects verbal communication., Objective: To assess the influence of facial paralysis on communicative participation., Design, Setting, and Participants: A nationwide online survey of 160 adults with unilateral facial paralysis was conducted from March 1 to June 1, 2017. To assess communicative participation, respondents completed the Communicative Participation Item Bank (CPIB) Short Form questionnaire and the Facial Clinimetric Evaluation (FaCE) Scale., Main Outcomes and Measures: The CPIB Short Form and the correlation between the CPIB Short Form and FaCE Scale. In the CPIB, the level of interference in communication is rated on a 4-point Likert scale (where not at all = 3, a little = 2, quite a bit = 1, and very much = 0). Total scores for the 10 items range from 0 (worst) to 30 (best). The FaCE Scale is a 15-item instrument that produces an overall score ranging from 0 (worst) to 100 (best), with higher scores representing better function and higher quality of life., Results: Of the 160 respondents, 145 (90.6%) were women and 15 were men (mean [SD] age, 45.1 [12.6] years). Most respondents reported having facial paralysis for more than 3 years. Causes of facial paralysis included Bell palsy (86 [53.8%]), tumor (41 [25.6%]), and other causes (33 [20.6%]), including infection, trauma, congenital defects, and surgical complications. The mean (SD) score on the CPIB Short Form was 0.16 (0.88) logits (range, -2.58 to 2.10 logits). The mean (SD) score of the FaCE Scale was 40.92 (16.05) (range, 0-83.3). Significant correlations were observed between the CPIB Short Form and overall FaCE Scale scores, as well as the Social Function, Oral Function, Facial Comfort, and Eye Comfort subdomains of the FaCE Scale, but not with the Facial Movement subdomain., Conclusions and Relevance: Patients with facial paralysis in this study sample reported restrictions in communicative participation that were comparable with restrictions experienced by patients with other known communicative disorders, such as laryngectomy and head and neck cancer. We believe that communicative participation represents a unique domain of dysfunction and can help quantify the outcome of facial paralysis and provide an additional frame of reference when assessing treatment outcomes.

Type II topoisomerases alter DNA topology to control DNA supercoiling and chromosome segregation and are targets of clinically important anti-infective and anticancer therapeutics. They act as ATP-operated clamps to trap a DNA helix and transport it through a transient break in a second DNA. Here, we present the first X-ray crystal structure solved at 2.83 Å of a closed clamp complete with trapped T-segment DNA obtained by co-crystallizing the ATPase domain of S. pneumoniae topoisomerase IV with a nonhydrolyzable ATP analogue and 14-mer duplex DNA. The ATPase dimer forms a 22 Å protein hole occupied by the kinked DNA bound asymmetrically through positively charged residues lining the hole, and whose mutagenesis impacts the DNA decatenation, DNA relaxation and DNA-dependent ATPase activities of topo IV. These results and a side-bound DNA-ParE structure help explain how the T-segment DNA is captured and transported by a type II topoisomerase, and reveal a new enzyme-DNA interface for drug discovery.

The auditory brainstem implant (ABI) is an auditory sensory device that is surgically placed on the cochlear nucleus of the brainstem for individuals who are deaf but unable to benefit from a cochlear implant (CI) due to anatomical abnormalities of the cochlea and/or eighth nerve, specific disease processes, or temporal bone fractures. In the United States, the Food and Drug Administration has authorized a Phase I clinical trial to determine safety and feasibility of the ABI in up to 10 eligible young children who are deaf and either derived no benefit from the CI or were anatomically unable to receive a CI. In this paper, we describe the study protocol and the children who have enrolled in the study thus far. In addition, we report the scores on speech perception, speech production, and language (spoken and signed) for five children with 1-3 years of assessment post-ABI activation. To date, the results indicate that spoken communication skills are slow to develop and that visual communication remains essential for post-ABI intervention.

Objective: To assess the prevalence of hearing loss and factors affecting hearing care use among Asian Americans, using the first nationally representative sample of Asian Americans., Study Design: National cross-sectional survey., Setting: Ambulatory examination centers., Patients: Three thousand six hundred twelve adults (522 Asian American) aged 20 to 69 in the 2011 to 2012 National Health and Examination Survey with pure-tone audiometry., Main Outcome Measure(s): Percentage with hearing loss, undertaking a hearing test before the study, and hearing aid use. Hearing loss was defined as better hearing ear speech frequency pure-tone average ≥25 dBHL. Analyses incorporated sampling weights to account for complex sampling design., Results: The prevalence of hearing loss was 6.0% [95% CI 3.1-8.9%] among Asian Americans, comparable to White, Black, and Hispanic groups, and increased substantially with age (OR: 2.25 [95% CI: 1.6-3.2]). After adjusting for age and pure-tone average, Asian Americans with hearing loss were less likely to have received a hearing test compared with White (OR: 0.27 [95% CI: 0.20-0.36, p = <0.001]) and Black groups (OR: 0.26 [95% CI: 0.16-0.38, p<0.001]), less likely to use hearing aids compared with Whites (OR: 0.06 [95% CI: 0.01-0.64], p = 0.02), and less likely to self-report poor hearing compared with Whites (OR: 0.30 [95% CI: 0.10-0.90], p = 0.03). Among Asian Americans, using more non-English than English, being foreign-born, less education, being married, and not having insurance were associated with lower levels of receiving a hearing test., Conclusion: The nationally representative sample of Asian Americans with hearing data suggests that hearing loss prevalence is similar to other races/ethnicities. However, hearing aid adoption by Asian Americans tends to be less frequent.

Objective: Imaging characteristics and hearing outcomes in children with cochleovestibular or cochleovestibular nerve (CVN) abnormalities., Study Design: Retrospective, critical review., Setting: Tertiary referral academic center., Patients: Twenty-seven children with CVN abnormalities with magnetic resonance (MRI) and/or computed tomography (CT). Study Intervention(s): None., Main Outcome Measure(s): Determine the likely presence or absence of a CNV and auditory stimulation responses., Results: Two of 27 cases had unilateral hearing loss, and all others had bilateral loss. Eleven (46%) were identified with a disability or additional condition. Twenty-two (42%) ears received a cochlear implant (CI) and 9 ears (17%) experienced no apparent benefit from the device. MRI acquisition protocols were suboptimal for identification of the nerve in 22 (42%) ears. A likely CVN absence was associated with a narrow cochlear aperture and internal auditory canal and cochlear malformation. Thirteen (48%) children with an abnormal nerve exhibited normal cochleae on the same side. Hearing data were available for 30 ears, and 25 ears (83%) exhibited hearing with or without an assistive device. One child achieved closed set speech recognition with a hearing aid, another with a CI. One child achieved open set speech recognition with a CI., Conclusions: Current imaging cannot accurately characterize the functional status of the CVN or predict an assistive device benefit. Children who would have otherwise been denied a CI exhibited auditory responses after implantation. A CI should be considered in children with abnormal CVN. Furthermore, imaging acquisition protocols need standardization for clear temporal bone imaging., (© 2018 S. Karger AG, Basel.)

Objectives/hypothesis: To characterize the histologic and biochemical properties of auricular and septal cartilage and analyze age-related changes in middle-aged to older adults., Study Design: Cross-sectional study of auricular and septal cartilage from 33 fresh cadavers., Methods: Auricular and septal cartilage specimens were stained using Safranin O for glycosaminoglycans, Verhoeff's stain for elastin, and Masson's trichrome for collagen. Percentage of tissue stained, cell density and size were quantified. Relationships between donor characteristics and histologic properties were evaluated using mixed model analyses., Results: The average donor age was 75 years (standard deviation = 11 years; range, 55-93 years). In auricular cartilage, each 1-year increase in age was associated with a 0.97% decrease in glycosaminoglycans (P < .001) and a 0.98% decrease in elastin (P < .001). In septal cartilage, glycosaminoglycans decreased 2.4% per year (P < .001). Age did not affect collagen content significantly in auricular (P = .417) or septal cartilage (P = .284). Cell density and cell size declined with age in auricular (both P < .001) and septal cartilage (P = .044, P = .032, respectively). Compared to septal cartilage in patients of all ages, auricular cartilage had more glycosaminoglycans, less collagen, higher cell density, and smaller cells., Conclusions: In auricular and septal cartilage, glycosaminoglycans, elastin, cell density, and cell size decrease significantly with age in patients over 55 years of age. Glycosaminoglycan content declines faster with age in septal cartilage than auricular cartilage. These age-related changes may affect biomechanical properties and tissue viability, and thereby have implications for graft choice in functional, aesthetic, and reconstructive nasal surgery., Level of Evidence: NA. Laryngoscope, 127:E399-E407, 2017., (© 2017 The American Laryngological, Rhinological and Otological Society, Inc.)

Objective: To determine the safety and feasibility of the auditory brainstem implant (ABI) in congenitally deaf children with cochlear aplasia and/or cochlear nerve deficiency., Study Design: Phase I feasibility clinical trial of surgery in 10 children, ages 2 to 5 years, over a 3-year period., Setting: Tertiary children's hospital and university-based pediatric speech/language/hearing center., Intervention(s): ABI implantation and postsurgical programming., Main Outcome Measure(s): The primary outcome measure is the number and type of adverse events during ABI surgery and postsurgical follow-up, including behavioral mapping of the device. The secondary outcome measure is access to and early integration of sound., Results: To date, nine children are enrolled. Five children have successfully undergone ABI surgery and postoperative behavioral programming. Three children were screen failures, and one child is currently undergoing candidacy evaluation. Expected adverse events have been documented in three of the five children who received the ABI. One child experienced a cerebral spinal fluid leak, which resolved with lumbar drainage. One child demonstrated vestibular side effects during device programming, which resolved by deactivating one electrode. One child experienced postoperative vomiting resulting in an abdominal radiograph. Four children have completed their 1-year follow-up and have speech detection thresholds of 30 to 35 dB HL. Scores on the IT-MAIS/MAIS range from 8 to 31 (out of a total of 40), and the children are demonstrating some ability to discriminate between closed-sets words that differ by number of syllables (pattern perception)., Conclusion: ABI surgery and device activation seem to be safe and feasible in this preliminary cohort.

As part of a programme of synthesizing and investigating the biological properties of new fluoroquinolone antibacterials and their targeting of topoisomerase IV from Streptococcus pneumoniae, we have solved the X-ray structure of the complexes of two new 7,8-bridged fluoroquinolones (with restricted C7 group rotation favouring tight binding) in complex with the topoisomerase IV from S. pneumoniae and an 18-base-pair DNA binding site-the E-site-found by our DNA mapping studies to bind drug strongly in the presence of topoisomerase IV (Leo et al. 2005 J. Biol. Chem. 280, 14 252-14 263, doi:10.1074/jbc.M500156200). Although the degree of antibiotic resistance towards fluoroquinolones is much lower than that of β-lactams and a range of ribosome-bound antibiotics, there is a pressing need to increase the diversity of members of this successful clinically used class of drugs. The quinolone moiety of the new 7,8-bridged agents ACHN-245 and ACHN-454 binds similarly to that of clinafloxocin, levofloxacin, moxifloxacin and trovofloxacin but the cyclic scaffold offers the possibility of chemical modification to produce interactions with other topoisomerase residues at the active site., (© 2016 The Authors.)

Background: Tracheoesophageal voice prostheses are invaluable for speech rehabilitation in patients who have received total laryngectomy, but device failure impedes communication and creates psychosocial and financial burdens. This study compares the Provox 2 and Provox Vega voice prostheses on the parameter of device life., Methods: This was a retrospective observational study of 21 patients with 181 device replacements at an academic tertiary care medical center. Disparity in device life and factors that may influence device life were analyzed., Results: The mean device life for Provox 2, at 115.6 days (SE = 5.8), was longer than for Provox Vega, at 65.1 days (SE = 7.5) (P < .001)., Conclusions: Device longevity was greater for Provox 2 over Provox Vega. These results will facilitate the design of prospective studies to assess reasons for variations in device life between patients and device types., (© The Author(s) 2016.)

Klebsiella pneumoniae is a Gram-negative bacterium that is responsible for a range of common infections, including pulmonary pneumonia, bloodstream infections and meningitis. Certain strains of Klebsiella have become highly resistant to antibiotics. Despite the vast amount of research carried out on this class of bacteria, the molecular structure of its topoisomerase IV, a type II topoisomerase essential for catalysing chromosomal segregation, had remained unknown. In this paper, the structure of its DNA-cleavage complex is reported at 3.35 Å resolution. The complex is comprised of ParC breakage-reunion and ParE TOPRIM domains of K. pneumoniae topoisomerase IV with DNA stabilized by levofloxacin, a broad-spectrum fluoroquinolone antimicrobial agent. This complex is compared with a similar complex from Streptococcus pneumoniae, which has recently been solved.

Objective: We investigated associations between sentence recognition and spoken language for children with cochlear implants (CI) enrolled in the Childhood Development after Cochlear Implantation (CDaCI) study., Study Design: In a prospective longitudinal study, sentence recognition percent-correct scores and language standard scores were correlated at 48-, 60-, and 72-months post-CI activation., Setting: Six tertiary CI centers in the United States., Patients: Children with CIs participating in the CDaCI study., Intervention (s): Cochlear implantation., Main Outcome Measure (s): Sentence recognition was assessed using the Hearing In Noise Test for Children (HINT-C) in quiet and at +10, +5, and 0 dB signal-to-noise ratio (S/N). Spoken language was assessed using the Clinical Assessment of Spoken Language (CASL) core composite and the antonyms, paragraph comprehension (syntax comprehension), syntax construction (expression), and pragmatic judgment tests., Results: Positive linear relationships were found between CASL scores and HINT-C sentence scores when the sentences were delivered in quiet and at +10 and +5 dB S/N, but not at 0 dB S/N. At 48 months post-CI, sentence scores at +10 and +5 dB S/N were most strongly associated with CASL antonyms. At 60 and 72 months, sentence recognition in noise was most strongly associated with paragraph comprehension and syntax construction., Conclusions: Children with CIs learn spoken language in a variety of acoustic environments. Despite the observed inconsistent performance in different listening situations and noise-challenged environments, many children with CIs are able to build lexicons and learn the rules of grammar that enable recognition of sentences.

Objectives/hypothesis: 1) To establish criteria for significant hearing fluctuation by assessing the range and occurrence of hearing fluctuations over the course of Meniere's disease; 2) to determine if audiometric evidence exists to support the notion that Meniere's disease is a pathophysiologic process involving the whole cochlea; and 3) to suggest prognostic implications for initial hearing fluctuation in patients with Meniere's disease., Study Design: Retrospective case series review., Methods: A total of 488 patients diagnosed by 1995 American Academy of Otolaryngology-Head and Neck Surgery Meniere's disease criteria for whom audiometric data were prospectively collected (2 cohorts: 341 and 146 patients initially seen between April 2002 to July 2003 and between January to December 2010, respectively). Based on several definitions for significant hearing fluctuation, change in hearing was categorized as "same," "worse," or "better" between any two consecutive evaluations. The relationship of initial hearing fluctuation to future hearing fluctuation and future hearing loss was evaluated., Results: Hearing fluctuation was evident in Meniere's disease patients with heterogeneous audiometric follow-up; and the characteristics of these hearing fluctuations, including the mean incidence, is described. Audiometric data suggests that there is a high congruence in Meniere's disease between changes in low- and high-frequency thresholds. Initial hearing fluctuation is associated with the occurrence of future and more frequent hearing fluctuations., Conclusion: Understanding the range of hearing fluctuations establishes a basis for determining audiometric thresholds used in evaluating future therapeutic trials aimed at the prevention of hearing loss in Meniere's disease. This knowledge will also inform the counseling directed toward patients diagnosed with Meniere's disease., (© 2015 The American Laryngological, Rhinological and Otological Society, Inc.)

Objective: To identify characteristics associated with the inability to progress to open-set speech recognition in children 5 years after cochlear implantation., Study Design: Prospective, longitudinal, and multidimensional assessment of auditory development for 5 years., Setting: Six tertiary cochlear implant (CI) referral centers in the United States., Patients: Children with severe-to-profound hearing loss who underwent implantation before age 5 years enrolled in the Childhood Development after Cochlear Implantation study, categorized by level of speech recognition ability., Intervention(s): Cochlear implantation before 5 years of age and annual assessment of emergent speech recognition skills., Main Outcome Measure(s): Progression to open-set speech recognition by 5 years after implantation., Results: Less functional hearing before implantation, older age at onset of amplification, lower maternal sensitivity to communication needs, minority status, and complicated perinatal history were associated with the inability to obtain open-set speech recognition by 5 years., Conclusion: Characteristics of a subpopulation of children with CIs associated with an inability to achieve open-set speech recognition after 5 years of CI experience were investigated. These data distinguish pediatric CI recipients at risk for poor auditory development and highlight areas for future interventions to enhance support of early implantation.

Objective: To evaluate the safety and efficacy of intratympanically injected golimumab (GLM), a TNF-α inhibitor, as a steroid-sparing agent for patients with steroid-dependent autoimmune inner ear disease (AIED)., Study Design: Open label., Setting: Tertiary referral center., Patients: Ten patients with steroid-dependent AIED were enrolled in Stage 2. The average patient age at enrollment was 59, with an average of 12.5 years from the start of bilateral hearing loss symptoms. The average dose of daily prednisone at the start of injections was 18 mg., Intervention: Intratympanic injection of GLM., Main Outcome Measure: Hearing loss progression (treatment failure) was defined as either an increase in pure-tone thresholds by frequency or a decrease in word recognition score., Results: There were no serious adverse events. Five of seven per-protocol subjects experienced stable pure-tone thresholds in the injected ear, whereas 4 had stable word recognition scores. Two subjects experienced an improvement in word recognition scores. The results support the hypothesis that GLM may be a promising treatment., Conclusions: The TNF-α inhibitor GLM stabilized hearing in 3 of 7 per-protocol subjects with AIED and allowed a complete tapering off of prednisone in those 7 subjects. Studies with larger samples sizes are warranted.

Background: Neurofibromatosis type 2 (NF2) is a rare autosomal dominant genetic disorder, resulting in a variety of neural tumors, with bilateral vestibular schwannomas as the most frequent manifestation. Recently, merlin, the NF2 tumor suppressor, has been identified as a novel negative regulator of mammalian target of rapamycin complex 1 (mTORC1); functional loss of merlin was shown to result in elevated mTORC1 signaling in NF2-related tumors. Thus, mTORC1 pathway inhibition may be a useful targeted therapeutic approach., Methods: We studied in vitro cell models, cohorts of mice allografted with Nf2(-/-) Schwann cells, and a genetically modified mouse model of NF2 schwannoma in order to evaluate the efficacy of the proposed targeted therapy for NF2., Results: We found that treatment with the mTORC1 inhibitor rapamycin reduced the severity of NF2-related Schwann cell tumorigenesis without significant toxicity. Consistent with these results, in an NF2 patient with growing vestibular schwannomas, the rapalog sirolimus induced tumor growth arrest., Conclusions: Taken together, these results constitute definitive evidence that justifies proceeding with clinical trials using mTORC1-targeted agents in selected patients with NF2 and in patients with NF2-related sporadic tumors.

Type II topoisomerases regulate DNA supercoiling and chromosome segregation. They act as ATP-operated clamps that capture a DNA duplex and pass it through a transient DNA break in a second DNA segment via the sequential opening and closure of ATPase-, G-DNA- and C-gates. Here, we present the first 'open clamp' structures of a 3-gate topoisomerase II-DNA complex, the seminal complex engaged in DNA recognition and capture. A high-resolution structure was solved for a (full-length ParE-ParC55)2 dimer of Streptococcus pneumoniae topoisomerase IV bound to two DNA molecules: a closed DNA gate in a B-A-B form double-helical conformation and a second B-form duplex associated with closed C-gate helices at a novel site neighbouring the catalytically important β-pinwheel DNA-binding domain. The protein N gate is present in an 'arms-wide-open' state with the undimerized N-terminal ParE ATPase domains connected to TOPRIM domains via a flexible joint and folded back allowing ready access both for gate and transported DNA segments and cleavage-stabilizing antibacterial drugs. The structure shows the molecular conformations of all three gates at 3.7 Å, the highest resolution achieved for the full complex to date, and illuminates the mechanism of DNA capture and transport by a type II topoisomerase.

Antibacterial fluoroquinolones trap a cleavage complex of gyrase and topoisomerase (topo) IV inducing site-specific DNA breakage within a bent DNA gate engaged in DNA transport. Despite its importance for drug action and in revealing potential sites of topoisomerase catalysis, the mechanism of DNA selectivity is poorly understood. To explore its functional basis, we generated mutant versions of the strongly cleaved E-site and used a novel competitive assay to examine their gemifloxacin-mediated DNA breakage by Streptococcus pneumoniae topo IV and gyrase. Parallel studies of Ca(2+)-induced cleavage distinguished 'intrinsic recognition' of DNA cleavage sites by topo IV from drug-induced preferences. Analysis revealed strong enzyme-determined requirements for -4G, -2A and -1T bases preceding the breakage site (between -1 and +1) and enzyme-unique or degenerate determinants at -3, plus drug-specific preferences at +2/+3 and for +1 purines associated with drug intercalation. Similar cleavage rules were seen additionally at the novel V-site identified here in ColE1-derived plasmids. In concert with DNA binding data, our results provide functional evidence for DNA, enzyme and drug contributions to DNA cleavage at the gate, suggest a mechanism for DNA discrimination involving enzyme-induced DNA bending/helix distortion and cleavage complex stabilization and advance understanding of fluoroquinolones as important cleavage-enhancing therapeutics.

Background: Ménière's disease (MD) is a debilitating disorder of the inner ear characterized by cochlear and vestibular dysfunction. The cause of this disease is still unknown, and epidemiological data for MD are sparse. From the existing literature, women seem to be more susceptible than men, and Caucasians seem to be more susceptible than Asians., Objective: In this article, we characterize a large definite MD cohort for sex and age of onset of disease and use molecular genetic methodologies to characterize ethnicity., Study Design: Medical record review for sex and age of onset. Ancestry analysis compared results from the principal component analysis of whole-genome genotype data from MD patients to self-identified ancestry in control samples., Setting: House Clinic in Los Angeles., Patients: Definitive MD patients., Results: Our review of medical records for definitive MD patients reveals that women are more susceptible than men. We also find that men and women have nearly identical age of onset for disease. Lastly, interrogation of molecular genetic data with principal component analysis allowed detailed observations about the ethnic ancestry of our patients. Comparison of the ethnicity of MD patients presenting to our tertiary care clinic with the self-recollected ethnicity of all patients visiting the clinic revealed an ethnic bias, with Caucasians presenting at a higher frequency than expected and the remaining major ethnicities populating Los Angeles (Hispanics, Blacks, and Asians) presenting at a lower frequency than expected., Conclusion: To the best of our knowledge, this report is the first ethnic characterization of a large MD cohort from a large metropolitan region using molecular genetic data. Our data suggest that there is a bias in sex and ethnic susceptibility to this disease.

Endovascular treatments for catastrophic aortic conditions have gained increasing popularity over the past 20 years. Originally developed for abdominal aortic aneurysms (EVAR), treatment has been modified for use in thoracic aortic repair (TEVAR). As expanding numbers of patients with increasingly intractable conditions and more hostile anatomies are treated, endovascular stent designs are maturing to be suitable for these more demanding situations. This article discusses the engineering considerations that apply to changing stent graft designs for current and evolving thoracic applications. The biological parameters that differentiate thoracic from abdominal aortic environments are outlined. Factors concerning materials, sealing mechanisms, deployment, stent frame architecture, and migration resistance are described, and eagerly awaited potential future developments are summarized., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Age-related hearing impairment (ARHI), or presbycusis, is a common condition of the elderly that results in significant communication difficulties in daily life. Clinically, it has been defined as a progressive loss of sensitivity to sound, starting at the high frequencies, inability to understand speech, lengthening of the minimum discernable temporal gap in sounds, and a decrease in the ability to filter out background noise. The causes of presbycusis are likely a combination of environmental and genetic factors. Previous research into the genetics of presbycusis has focused solely on hearing as measured by pure-tone thresholds. A few loci have been identified, based on a best ear pure-tone average phenotype, as having a likely role in susceptibility to this type of hearing loss; and GRM7 is the only gene that has achieved genome-wide significance. We examined the association of GRM7 variants identified from the previous study, which used an European cohort with Z-scores based on pure-tone thresholds, in a European-American population from Rochester, NY (N = 687), and used novel phenotypes of presbycusis. In the present study mixed modeling analyses were used to explore the relationship of GRM7 haplotype and SNP genotypes with various measures of auditory perception. Here we show that GRM7 alleles are associated primarily with peripheral measures of hearing loss, and particularly with speech detection in older adults., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Objective: To determine the effect of oral steroid treatment on hearing in unilateral Ménière's disease and endolymphatic hydrops patients., Study Design: Retrospective chart review., Setting: Tertiary referral center., Patients: All patients presenting during the 2010 calendar year with confirmed unilateral Ménière's disease or endolymphatic hydrops. Those with a first visit and second visit audiogram (n = 58) were included in the analysis of oral steroid treatment effect., Intervention: Steroid treatment for hearing loss., Main Outcome Measure: Change in hearing, as defined by change in affected ear threshold values or speech discrimination score from pretreatment visit to posttreatment visit., Results: Hearing (threshold, speech discrimination score) in patients' affected ear did not significantly change from first visit to second visit after treatment with steroids relative to patients who did not receive steroid treatment., Conclusion: The results of this and other studies would indicate that a Ménière's disease or endolymphatic hydrops patient is unlikely to experience an improvement in hearing from a short course of oral steroid. Clinically observed temporary improvement did not sustain over several months. Further work to elucidate the mechanisms underlying hearing loss in hydrops, perhaps focusing on the dendrite damage noted in animal models of hydrops, is warranted.

Background: Speech recognition in noise testing has been conducted at least since the 1940s (Dickson et al, 1946). The ability to recognize speech in noise is a distinct function of the auditory system (Plomp, 1978). According to Kochkin (2002), difficulty recognizing speech in noise is the primary complaint of hearing aid users. However, speech recognition in noise testing has not found widespread use in the field of audiology (Mueller, 2003; Strom, 2003; Tannenbaum and Rosenfeld, 1996). The audiogram has been used as the "gold standard" for hearing ability. However, the audiogram is a poor indicator of speech recognition in noise ability., Purpose: This study investigates the relationship between pure-tone thresholds, the articulation index, and the ability to recognize speech in quiet and in noise., Research Design: Pure-tone thresholds were measured for audiometric frequencies 250-6000 Hz. Pure-tone threshold groups were created. These included a normal threshold group and slight, mild, severe, and profound high-frequency pure-tone threshold groups. Speech recognition thresholds in quiet and in noise were obtained using the Hearing in Noise Test (HINT) (Nilsson et al, 1994; Vermiglio, 2008). The articulation index was determined by using Pavlovic's method with pure-tone thresholds (Pavlovic, 1989, 1991)., Study Sample: Two hundred seventy-eight participants were tested. All participants were native speakers of American English. Sixty-three of the original participants were removed in order to create groups of participants with normal low-frequency pure-tone thresholds and relatively symmetrical high-frequency pure-tone threshold groups. The final set of 215 participants had a mean age of 33 yr with a range of 17-59 yr., Data Collection and Analysis: Pure-tone threshold data were collected using the Hughson-Weslake procedure. Speech recognition data were collected using a Windows-based HINT software system. Statistical analyses were conducted using descriptive, correlational, and multivariate analysis of covariance (MANCOVA) statistics., Results: The MANCOVA analysis (where the effect of age was statistically removed) indicated that there were no significant differences in HINT performances between groups of participants with normal audiograms and those groups with slight, mild, moderate, or severe high-frequency hearing losses. With all of the data combined across groups, correlational analyses revealed significant correlations between pure-tone averages and speech recognition in quiet performance. Nonsignificant or significant but weak correlations were found between pure-tone averages and HINT thresholds., Conclusions: The ability to recognize speech in steady-state noise cannot be predicted from the audiogram. A new classification scheme of hearing impairment based on the audiogram and the speech reception in noise thresholds, as measured with the HINT, may be useful for the characterization of the hearing ability in the global sense. This classification scheme is consistent with Plomp's two aspects of hearing ability (Plomp, 1978)., (American Academy of Audiology.)

Bilateral cochlear implant patients are unable to localize as well as normal hearing listeners. Although poor sensitivity to interaural time differences clearly contributes to this deficit, it is unclear whether deficits in terms of interaural level differences are also a contributing factor. In this study, localization was tested while manipulating interaural time and level cues using head-related transfer functions. The results indicate that bilateral cochlear implant users' ability to localize based on interaural level differences is actually greater than that of untrained normal hearing listeners.

The safety of artemether-lumefantrine in patients with acute, uncomplicated Plasmodium falciparum malaria was investigated prospectively using the auditory brainstem response (ABR) and pure-tone thresholds. Secondary outcomes included polymerase chain reaction-corrected cure rates. Patients were randomly assigned in a 3:1:1 ratio to either artemether-lumefantrine (N = 159), atovaquone-proguanil (N = 53), or artesunate-mefloquine (N = 53). The null hypothesis (primary outcome), claiming that the percentage of patients with a baseline to Day-7 ABR Wave III latency increase of > 0.30 msec is ≥ 15% after administration of artemether-lumefantrine, was rejected; 2.6% of patients (95% confidence interval: 0.7-6.6) exceeded 0.30 msec, i.e., significantly below 15% (P < 0.0001). A model-based analysis found no apparent relationship between drug exposure and ABR change. In all three groups, average improvements (2-4 dB) in pure-tone thresholds were observed, and polymerase chain reaction-corrected cure rates were > 95% to Day 42. The results support the continued safe and efficacious use of artemether-lumefantrine in uncomplicated falciparum malaria.

Objective: To assess the duration of hearing preservation from time of vestibular schwannoma middle fossa decompression with short-term and 1-year hearing preservation rates., Study Design: Retrospective case review., Setting: Tertiary referral center., Patients: Patients with and without neurofibromatosis type 2 who underwent middle fossa decompression. We excluded patients without tumor size or audiograms at initial diagnosis or follow-up less than 3 months., Interventions: Middle cranial fossa decompression, audiometry, and magnetic resonance imaging., Main Outcome Measures: Period of hearing maintenance (from surgery to longest time point that preoperative American Academy of Otolaryngology-Head and Neck Surgery [AAO-HNS] hearing class maintained or improved), short-term hearing preservation (within 3 mo of surgery), and 1-year hearing preservation., Results: A total of 49 patients underwent middle fossa decompression of vestibular schwannoma. Approximately 90% of patients had documented hearing loss before surgery, and more than 50% of patients exhibited significant tumor growth before surgery. Of these surgeries, more than 90% were performed in patients with hearing loss in an only hearing ear, and more than 90% were patients with neurofibromatosis type 2. The mean period of hearing maintenance was 2.1 years. The short-term hearing preservation rate as measured by the change from preoperative AAO-HNS hearing class was approximately 90%. The 1-year hearing preservation rate as measured by change from preoperative AAO-HNS hearing class was 63%., Conclusion: Middle fossa decompression for vestibular schwannoma can prolong hearing in patients with hearing changes in an only hearing ear. Understanding the duration of hearing preservation can enable more effective counseling of patients considering middle cranial fossa decompression for vestibular schwannoma.

Objectives: Cochlear implant microphones differ in placement, frequency response, and other characteristics such as whether they are directional. Although normal-hearing (NH) individuals are often used as controls in studies examining cochlear implant users' binaural benefits, the considerable differences across cochlear implant microphones make such comparisons potentially misleading. The goal of this study was to examine binaural benefits for speech perception in noise for NH individuals using stimuli processed by head-related transfer functions (HRTFs) based on the different cochlear implant microphones., Design: HRTFs were created for different cochlear implant microphones and used to test participants on the Hearing in Noise Test. Experiment 1 tested cochlear implant users and NH individuals with HRTF-processed stimuli and with sound field (SF) testing to determine whether the HRTFs adequately simulated SF testing. Experiment 2 determined the measurement error and performance-intensity function for the Hearing in Noise Test with NH individuals listening to stimuli processed with the various HRTFs. Experiment 3 compared NH listeners' performance across HRTFs to determine how the HRTFs affected performance. Experiment 4 evaluated binaural benefits for NH listeners using the various HRTFs, including ones that were modified to investigate the contributions of interaural time and level cues., Results: The results indicated that the HRTFs adequately simulated SF testing for the Hearing in Noise Test. They also demonstrated that the test-retest reliability and performance-intensity function were consistent across HRTFs, and that the measurement error for the test was 1.3 dB, with a change in signal-to-noise ratio of 1 dB reflecting a 10% change in intelligibility. There were significant differences in performance when using the various HRTFs, with particularly good thresholds for the HRTF based on the directional microphone when the speech and masker were spatially separated, emphasizing the importance of measuring binaural benefits separately for each HRTF. Evaluation of binaural benefits indicated that binaural squelch and spatial release from masking were found for all HRTFs, and binaural summation was found for all but one HRTF, although binaural summation was less robust than the other types of binaural benefits. In addition, the results indicated that neither interaural time nor level cues dominated binaural benefits for the NH participants., Conclusions: This study provides a means to measure the degree to which cochlear implant microphones affect acoustic hearing with respect to speech perception in noise. It also provides measures that can be used to evaluate the independent contributions of interaural time and level cues. These measures provide tools that can aid researchers in understanding and improving binaural benefits in acoustic hearing individuals listening via cochlear implant microphones.

Type II DNA topoisomerases are ubiquitous enzymes with essential functions in DNA replication, recombination and transcription. They change DNA topology by forming a transient covalent cleavage complex with a gate-DNA duplex that allows transport of a second duplex though the gate. Despite its biological importance and targeting by anticancer and antibacterial drugs, cleavage complex formation and reversal is not understood for any type II enzyme. To address the mechanism, we have used X-ray crystallography to study sequential states in the formation and reversal of a DNA cleavage complex by topoisomerase IV from Streptococcus pneumoniae, the bacterial type II enzyme involved in chromosome segregation. A high resolution structure of the complex captured by a novel antibacterial dione reveals two drug molecules intercalated at a cleaved B-form DNA gate and anchored by drug-specific protein contacts. Dione release generated drug-free cleaved and resealed DNA complexes in which the DNA gate instead adopts an unusual A/B-form helical conformation with a Mg(2+) ion repositioned to coordinate each scissile phosphodiester group and promote reversible cleavage by active-site tyrosines. These structures, the first for putative reaction intermediates of a type II topoisomerase, suggest how a type II enzyme reseals DNA during its normal reaction cycle and illuminate aspects of drug arrest important for the development of new topoisomerase-targeting therapeutics.

Objective: To compare proportions of the combined outcome of vertigo control and hearing preservation between intratympanic gentamicin injections and endolymphatic sac shunt surgery for intractable vertigo in Ménière's disease patients., Study Design: Analysis of published data and retrospective review., Setting: Tertiary otologic referral center., Patients: Patients with Ménière's disease who had failed medical management: 183 surgical patients (shunt group) and 203 patients obtained from 6 published gentamicin treatment studies (gentamicin group). Cases were included if hearing and vertigo data were available before and after treatment with no previous surgical or injection treatment. Average patient age ranged from 45 to 59 years across studies. Gentamicin studies had nearly equal female to male subjects, whereas the shunt group was 60% female., Interventions: Endolymphatic sac shunt surgery or intratympanic gentamicin treatment of differing doses and injection schedules., Main Outcome Measure: Proportion of patients with best combined vertigo control/hearing preservation. Hearing preservation is 10 dB or less increase in pure-tone average. Outcomes were categorized as follows: complete vertigo control/hearing preservation (best), complete vertigo control/hearing loss, incomplete vertigo control/hearing preservation, and incomplete vertigo control/hearing loss (worst)., Results: The shunt group showed a significantly higher percentage of the best outcome (62%) than the gentamicin group (56%, p

Objective: Review publications reporting radiation treatment of vestibular schwannomas (VS) and describe how data, patient characteristics, and study endpoints were reported., Data Sources: PubMed search for English language articles on radiation treatment of VS published from January 2002 to July 2007., Study Selection: Studies presenting outcomes were selected, yielding 56 articles (58 studies) in journals of neurosurgery (30), oncology (18), otolaryngology (6), and other (2)., Data Extraction/synthesis: Data included type of study, number of subjects, demographics, follow-up times, type of radiation, tumor size, tumor control definition, control rates, facial nerve function measure and outcome, type of hearing and vestibular testing and outcomes, and complications. Descriptive statistics were performed., Results: Studies (72.9%) were retrospective reviews with stated sample sizes ranging from 5 to 829. Gamma-knife (49.2%), linear accelerator (35.6%), and proton beam (6.8%) were used with various doses. Average follow-up was less than 5 years in 79.6% of studies, and 67.4% included patients at less than or equal to 1 year. Tumor size was reported as diameter (23.7%), volume (49.2%), both (11.9%), other (3.4%), or not reported (11.9%). Definition of tumor control varied: less than or equal to 2 mm growth (22.0%), no visible/measurable change (16.9%), required surgery (10.2%), other (17.0%), and not clearly specified (33.9%). Facial nerve outcome was reported as House-Brackmann (64.4%), normal/abnormal (11.9%), other (1.7%), or was not reported (22%)., Conclusion: The lack of uniform reporting criteria for tumor control, facial function and hearing preservation, and variability in follow-up times make it difficult to compare studies of radiation treatment for VS. We recommend consideration of reporting guidelines such as those used in otology for reporting VS resection results.

Objectives/hypothesis: Determine the benefit of the bone-anchored hearing aid (BAHA) in patients with unilateral deafness., Study Design: Retrospective case series and prospective questionnaire study at a tertiary referral center., Methods: Patients with unilateral deafness of various etiologies who were implanted with a BAHA (n = 126) or not implanted with a BAHA after a translabyrinthine craniotomy (n = 126) were mailed questionnaires. A total of 139 patients (55%) responded to the questionnaires. Patients who were implanted with a BAHA received a general questionnaire concerning BAHA usage, the Abbreviated Profile of Hearing Aid Benefit (APHAB), and the Speech, Spatial, and Qualities of Hearing Questionnaire (SSQ). Patients not implanted with a BAHA received only the SSQ hearing questionnaire., Results: Patients with unilateral deafness demonstrated a benefit with BAHA use on the APHAB. Most improvement with the BAHA was seen in the Background Noise subscale, with a 17.4% improvement. Ease of Communication and Reverberation subscales also demonstrated an 11.6% and 13.2% benefit, respectively. Patients with a BAHA demonstrated better scores in the SSQ Speech subscale when compared to unilaterally deaf patients who did not have a BAHA, although this difference was not significant., Conclusions: The APHAB demonstrated significant benefit with the use of a BAHA in patients with unilateral deafness. Although the SSQ speech subscale showed overall improvement in auditory disability with the use of a BAHA, this difference was not significant. However, the SSQ hearing questionnaire demonstrated specific situations were the BAHA is most useful.

Quinazoline-2,4-diones, such as PD 0305970, are new DNA gyrase and topoisomerase IV (topo IV) inhibitors with potent activity against gram-positive pathogens, including quinolone-resistant isolates. The mechanistic basis of dione activity vis-à-vis quinolones is not understood. We present evidence for Streptococcus pneumoniae gyrase and topo IV that PD 0305970 and quinolones interact differently with the enzyme breakage-reunion and Toprim domains, DNA, and Mg2+-four components that are juxtaposed in the topoisomerase cleavage complex to effect DNA scission. First, PD 0305970 targets primarily gyrase in Streptococcus pneumoniae. However, unlike quinolones, which select predominantly for gyrA (or topo IV parC) mutations in the breakage-reunion domain, unusually the dione selected for novel mutants with alterations that map to a region of the Toprim domain of GyrB (R456H and E474A or E474D) or ParE (D435H and E475A). This "dione resistance-determining region" overlaps the GyrB quinolone resistance-determining region and the region that binds essential Mg2+ ions, each function involving conserved EGDSA and PLRGK motifs. Second, dione-resistant gyrase and topo IV were inhibited by ciprofloxacin, whereas quinolone-resistant enzymes (GyrA S81F and ParC S79F) remained susceptible to PD 0305970. Third, dione-promoted DNA cleavage by gyrase occurred at a distinct repertoire of sites, implying that structural differences with quinolones are sensed at the DNA level. Fourth, unlike the situation with quinolones, the Mg2+ chelator EDTA did not reverse dione-induced gyrase cleavage nor did the dione promote Mg2+-dependent DNA unwinding. It appears that PD 0305970 interacts uniquely to stabilize the cleavage complex of gyrase/topo IV perhaps via an altered orientation directed by the bidentate 3-amino-2,4-dione moiety.

Objective: To examine the relationship between the amount of change in size and associated hearing in bilateral vestibular schwannomas (VSs) in persons with neurofibromatosis 2 (NF2)., Study Design: Annual magnetic resonance imaging and audiological examinations were conducted on NF2 patients., Subjects: Fifty-two patients enrolled in the NF2 Natural History Consortium in whom both VSs were untreated. Magnetic resonance imaging and hearing exams were available for at least 2 time points 1 year apart. The 32 males and 20 females had a mean age at diagnosis of 26 years (SD = 18). In 19 (37%) subjects, the NF2 germline mutation could not be identified in the blood (mosaic)., Outcome Measures: Greatest diameter change in tumor size for each of the 2 tumors from first to second evaluation was determined. Differences in amounts of change between the 2 sides and in hearing (4-frequency pure-tone average) were evaluated using multivariate analysis of variance., Results: Overall, the VSs demonstrated significant average growth (p < 0.001), and hearing worsened significantly (p < 0.001) over 1 year. The amount of change in the bigger tumors was not associated with the amount of change in the smaller tumors within each patient. Vestibular schwannoma size changes were not associated with the corresponding hearing changes (Kendall's tau, p = not significant [n.s.])., Conclusion: A significant 1-year change in VS size and hearing occurred in NF2 patients. Clinically, tumor change or hearing deterioration on one VS cannot be used to predict changes in the other VS. This suggests that, although NF2 is a Mendelian disease, the germline genotype-phenotype relationship may resemble that of complex disorders.

We describe the outcomes of a practice exchange in which an isolated general practitioner from a remote region traded work and living arrangements with a rural group practice GP. An exchange can provide an opportunity for mid- and senior-career professionals to refresh their outlook on their careers. Involving the rural medical workforce in practice exchanges can enable the development of peer networks that can improve retention of isolated practitioners in Australia. A fresh experience in a new setting can provide opportunities for practitioners to improve practice management and sharpen their clinical skills. Uprooting families and preparing homes for unfamiliar visitors add stress to doctors and their families on exchange. Patients in isolated practices could feel concerned that they may lose their doctor as a result of an exchange. In this instance, the benefits far outweighed the difficulties.

Type II topoisomerases alter DNA topology by forming a covalent DNA-cleavage complex that allows DNA transport through a double-stranded DNA break. We present the structures of cleavage complexes formed by the Streptococcus pneumoniae ParC breakage-reunion and ParE TOPRIM domains of topoisomerase IV stabilized by moxifloxacin and clinafloxacin, two antipneumococcal fluoroquinolones. These structures reveal two drug molecules intercalated at the highly bent DNA gate and help explain antibacterial quinolone action and resistance.

Objectives: Besifloxacin is a new fluoroquinolone in development for ocular use. We investigated its mode of action and resistance in two major ocular pathogens, Streptococcus pneumoniae and Staphylococcus aureus, and in the reference species Escherichia coli., Methods: Primary and secondary targets of besifloxacin were evaluated by: (i) mutant selection experiments; (ii) MIC testing of defined topoisomerase mutants; and (iii) inhibition and cleavable complex assays with purified S. pneumoniae and E. coli DNA gyrase and topoisomerase IV enzymes., Results: Enzyme assays showed similar besifloxacin activity against S. pneumoniae gyrase and topoisomerase IV, with IC(50) and CC(25) of 2.5 and 1 microM, respectively. In contrast to ciprofloxacin and moxifloxacin, besifloxacin was equally potent against both S. pneumoniae and E. coli gyrases. DNA gyrase was the primary target in all three species, with substitutions observed at positions 81, 83 and 87 in GyrA and 426 and 466 in GyrB (E. coli numbering). Topoisomerase IV was the secondary target. Notably, resistant mutants were not recovered at 4-fold besifloxacin MICs for S. aureus and S. pneumoniae, and S. aureus topoisomerase mutants were only obtained after serial passage in liquid medium. Besifloxacin MICs were similarly affected by parC or gyrA mutations in S. aureus and S. pneumoniae and remained below 1 mg/L in gyrA-parC double mutants., Conclusions: Although mutant selection experiments indicated that gyrase is a primary target, further biochemical and genetic studies showed that besifloxacin has potent, relatively balanced activity against both essential DNA gyrase and topoisomerase IV targets in S. aureus and S. pneumoniae.

Clerocidin (CL), a microbial diterpenoid, reacts with DNA via its epoxide group and stimulates DNA cleavage by type II DNA topoisomerases. The molecular basis of CL action is poorly understood. We establish by genetic means that CL targets DNA gyrase in the gram-positive bacterium Streptococcus pneumoniae, and promotes gyrase-dependent single- and double-stranded DNA cleavage in vitro. CL-stimulated DNA breakage exhibited a strong preference for guanine preceding the scission site (-1 position). Mutagenesis of -1 guanines to A, C or T abrogated CL cleavage at a strong pBR322 site. Surprisingly, for double-strand breaks, scission on one strand consistently involved a modified (piperidine-labile) guanine and was not reversed by heat, salt or EDTA, whereas complementary strand scission occurred at a piperidine-stable -1 nt and was reversed by EDTA. CL did not induce cleavage by a mutant gyrase (GyrA G79A) identified here in CL-resistant pneumococci. Indeed, mutations at G79 and at the neighbouring S81 residue in the GyrA breakage-reunion domain discriminated poisoning by CL from that of antibacterial quinolones. The results suggest a novel mechanism of enzyme inhibition in which the -1 nt at the gyrase-DNA gate exhibit different CL reactivities to produce both irreversible and reversible DNA damage.

Background: Streptococcus pneumoniae is the major cause of community-acquired pneumonia and is also associated with bronchitis, meningitis, otitis and sinusitis. The emergence and increasing prevalence of resistance to penicillin and other antibiotics has led to interest in other anti-pneumonococcal drugs such as quinolones that target the enzymes DNA gyrase and topoisomerase IV. During crystallization and in the avenues to finding a method to determine phases for the structure of the ParC55 breakage-reunion domain of topoisomerase IV from Streptococcus pneumoniae, obstacles were faced at each stage of the process. These problems included: majority of the crystals being twinned, either non-diffracting or exhibiting a high mosaic spread. The crystals, which were grown under conditions that favoured diffraction, were difficult to flash-freeze without loosing diffraction. The initial structure solution by molecular replacement failed and the approach proved to be unviable due to the complexity of the problem. In the end the successful structure solution required an in-depth data analysis and a very detailed molecular replacement search., Methodology/principal Findings: Crystal anti-twinning agents have been tested and two different methods of flash freezing have been compared. The fragility of the crystals did not allow the usual method of transferring the crystals into the heavy atom solution. Consequently, it was necessary to co-crystallize in the presence of the heavy atom compound. The multiple isomorphous replacement approach was unsuccessful because the 7 cysteine mutants which were engineered could not be successfully derivatized. Ultimately, molecular replacement was used to solve the structure by sorting through a large number of solutions in space group P1 using CNS., Conclusions/significance: The main objective of this paper is to describe the obstacles which were faced and overcome in order to acquire data sets on such difficult crystals and determine phases for successful structure solution.

Objectives/hypothesis: To determine the efficacy of prophylactic famciclovir to significantly reduce the percentage of patients experiencing postoperative delayed facial paresis., Study Design: Prospective evaluation of facial nerve grade for two groups (treated and untreated) with famciclovir before and after surgery. All procedures were conducted by the same group of experienced neurotologists., Methods: In a tertiary neurotologic private practice, the percentage of 1,023 patients with delayed facial paresis after undergoing microsurgical removal of unilateral acoustic tumor with no preoperative treatment was compared to the percentage of 530 patients with preoperative famciclovir treatment. Patients were prescribed famciclovir 500 mg BID for 3 days before surgery and 5 days postoperative. The House-Brackmann Facial Nerve Grade was assessed prospectively at preoperative, immediate postoperative, and discharge from the hospital in both groups., Results: Twenty-five percent of the no famciclovir group experienced delayed facial palsy compared to 20% in the famciclovir group, a statistically significant difference (P < .04). The famciclovir group undergoing translabyrinthine craniotomy showed a significantly greater decrease in percentage of patients with delayed facial palsy than those undergoing middle fossa craniotomies (P < .003)., Conclusions: Famciclovir administered preoperatively and after craniotomies resulted in a smaller percentage of patients developing delayed facial weakness. We are continuing the routine use of famciclovir in perioperative acoustic tumor management and recommend that others do so.

DNA gyrase and DNA topoisomerase (topo) IV are the bacterial targets of coumarin and quinolone antimicrobial agents. Widespread resistance to clinically important antibiotics such as beta-lactams and macrolides has stimulated the development of novel gyrase and topo IV inhibitors especially against Streptococcus pneumoniae and other Gram-positive pathogens. Here, we describe how gyrase and topo IV activities are measured and how inhibitors of these enzymes may be assayed, focusing as a paradigm on DNA supercoiling by S. pneumoniae gyrase, DNA decatenation by S. pneumoniae topo IV, and DNA cleavage by both enzymes. These approaches provide mechanistic insight on inhibitor action and allow identification of dual gyrase/topo IV targeting agents that can minimize the emergence of bacterial resistance.

Objective: To describe the prevalence and location of cranial nerve schwannomas, other than bilateral vestibular schwannoma, in patients with neurofibromatosis 2 (NF2). The NF2 Natural History Consortium prospectively gathered cranial magnetic resonance imaging for 83 patients across 3 annual evaluations. The time between the first and last evaluation was approximately 3 years., Results: Forty-two patients (51%) had nonvestibular cranial nerve schwannomas (NVSs). Of these, 25 (60%) also had cranial meningiomas. Twenty-one of those without NVS (25% of 83) had at least 1 meningioma. The average size of the NVS was 0.4 cubic centimeters. Overall, there was no significant change in NVS size from Year 1 to Year 3 or from Year 1 to Year 2. The most common locations of the NVS were occulomotor and trigeminal. A family history of NF2 did not predict NVS location or growth., Conclusion: Nonvestibular cranial nerve schwannoma usually affect cranial nerves III and V, as was the case in our NF2 sample. Fortunately, neuropathies associated with these tumors are rare. In contrast, lower cranial nerve schwannomas, although also rare, are associated with swallowing difficulty, aspiration, and other sequelae.