BACKGROUND The nervous system may include more than 100 residue-specific posttranslational modifications of histones forming the nucleosome core that are often regulated in cell-type-specific manner. On a genome-wide scale, some of the histone posttranslational modification landscapes show significant overlap with the genetic risk architecture for several psychiatric disorders, fueling PsychENCODE and other large-scale efforts to comprehensively map neuronal and nonneuronal epigenomes in hundreds of specimens. However, practical guidelines for efficient generation of histone chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) datasets from postmortem brains are needed. METHODS Protocols and quality controls are given for the following: 1) extraction, purification, and NeuN neuronal marker immunotagging of nuclei from adult human cerebral cortex; 2) fluorescence-activated nuclei sorting; 3) preparation of chromatin by micrococcal nuclease digest; 4) ChIP for open chromatin-associated histone methylation and acetylation; and 5) generation and sequencing of ChIP-seq libraries. RESULTS We present a ChIP-seq pipeline for epigenome mapping in the neuronal and nonneuronal nuclei from the postmortem brain. This includes a stepwise system of quality controls and user-friendly data presentation platforms. CONCLUSIONS Our practical guidelines will be useful for projects aimed at histone posttranslational modification mapping in chromatin extracted from hundreds of postmortem brain samples in cell-type-specific manner.

Cochlear implants are a very cost-effective treatment for profound hearing loss in all high-resource countries and in many low-income and middle-income developing countries. A number of cost considerations affect cost-effectiveness of cochlear implants in developing countries including device cost and device-related expenses such as power consumption and reliability, but also including rehabilitation and access-related expenses. Large-scale programmes confer an advantage for cost-effectiveness, primarily through device-related savings.

Objective: Determine whether an electronic tablet-based Wireless Automated Hearing-Test System can perform high-quality audiometry to assess schoolchildren for hearing loss in the field in Nicaragua. Study Design: Cross-sectional. Setting: A school and hospital-based audiology clinic in Jinotega, Nicaragua. Subjects and Methods: Second and third graders (n = 120) were randomly selected for hearing testing in a school. Air conduction hearing thresholds were obtained bilaterally using a Wireless Automated Hearing-Test System at 1000, 2000, and 4000 Hz. Referral criteria were set at more than 25 dBHL at one or more frequencies. A cohort of children was retested with conventional audiometry in a hospital-based sound booth. Factors influencing false-positive examinations, including ambient noise and behavior, were examined. Results: All children with hearing loss were detected using an automated, manual, or two-step (those referred from automated testing were tested manually) protocol in the school (sensitivity = 100%). Specificity was 76% for automated testing, 97% for manual testing, and 99% for the two-step protocol. The variability between thresholds obtained with automated testing was greater than manual testing when compared with conventional audiometry. The percentage of participant responses when no stimulus tone was presented during automated testing was higher in children with false-positive examinations. Conclusion: A Wireless Automated Hearing-Test System identified all children with hearing loss in a challenging field setting. A two-step protocol (those referred from automated testing are tested manually) reduced false-positive examinations and unnecessary referrals. Children who respond frequently when no tone is presented are more likely to have false-positive automated examinations and should be tested manually.

Objective To describe the developmental anatomy of the eustachian tube (ET) and its relationship to surrounding structures on computed tomography. Study Design Case series with chart review. Setting A tertiary care hospital. Methods ET anatomy was assessed with reformatted high-resolution computed tomography scans from 2010 to 2018. Scans (n = 78) were randomly selected from the following age groups: <4, 5 to 7, 8 to 18, and >18 years. The following were measured and compared between groups: ET length, angles, and relationship between its bony cartilaginous junction and the internal carotid artery and between its nasopharyngeal opening and the nasal floor. Results The distance between the bony cartilaginous junction and internal carotid artery decreased with age between the <4-year-olds (2.4 ± 0.6 mm) and the 5- to 7-year-olds (2.0 ± 0.3 mm, P = .001). The ET length increased among the <4-year-olds (32 mm), 5- to 7-year-olds (36 mm), and 8- to 18-year-olds (41 mm, P < .0001). The cartilaginous ET increased among the <4-year-olds (20 mm), 5- to 7-year-olds (25 mm), and 8- to 18-year-olds (28 mm, P < .0001). The ET horizontal angle increased among the <4-year-olds (17°), 5- to 7-year-olds (21°), and 8- to 18-year-olds (23°, P≤ .003), but the ET sagittal angle did not statistically change after 5 years of age. The height difference between the nasopharyngeal opening of the ET and the nasal floor increased among the <4-year-olds (4 mm), 5- to 7-year-olds (7 mm), and 8- to 18-year-olds (11 mm, P < .0001). Conclusion The ET elongates with age, and its angles and relationship to the nasal floor increase. Although some parameters mature faster, more than half of the ET growth occurs by 8 years of age, and adult morphology is achieved by early adolescence.

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