Intra- and Interrater Reliability of CT- versus MRI-Based Cochlear Duct Length Measurement in Pediatric Cochlear Implant Candidates and Its Impact on Personalized Electrode Array Selection.

BACKGROUND: Radiological high-resolution computed tomography-based evaluation of cochlear implant candidates' cochlear duct length (CDL) has become the method of choice for electrode array selection. The aim of the present study was to evaluate if MRI-based data match CT-based data and if this impacts on electrode array choice. METHODS: Participants were 39 children. CDL, length at two turns, diameters, and height of the cochlea were determined via CT and MRI by three raters using tablet-based otosurgical planning software. Personalized electrode array length, angular insertion depth (AID), intra- and interrater differences, and reliability were calculated. RESULTS: Mean intrarater difference of CT- versus MRI-based CDL was 0.528 ± 0.483 mm without significant differences. Individual length at two turns differed between 28.0 mm and 36.6 mm. Intrarater reliability between CT versus MRI measurements was high (intra-class correlation coefficient (ICC): 0.929-0.938). Selection of the optimal electrode array based on CT and MRI matched in 90.1% of cases. Mean AID was 629.5° based on the CT and 634.6° based on the MRI; this is not a significant difference. ICC of the mean interrater reliability was 0.887 for the CT-based evaluation and 0.82 for the MRI-based evaluation. CONCLUSION: MRI-based CDL measurement shows a low intrarater difference and a high interrater reliability and is therefore suitable for personalized electrode array selection.

Measuring 25-hydroxyvitamin D in cats: comparison of a whole-blood lateral flow assay, 2 dried-blood-spot tests, and serum LC-MS/MS.

Measuring 25-hydroxyvitamin D (25D) can be a challenge in veterinary medicine because of laboratory accessibility and required sample volume. We compared 2 dried-blood-spot (DBS) tests and a lateral flow assay (LFA) to the gold standard, liquid chromatography-tandem mass spectrometry (LC-MS/MS). We hypothesized that there would be good agreement among the tests, within a clinically significant limit of agreement of ± 25 nmol/L. We collected blood from 6 healthy purpose-bred 2-y-old cats at 6 times over 6 wk, and measured 25D concentrations with all 4 tests. Agreement of the 3 candidate tests and LC-MS/MS was evaluated via Bland-Altman analysis, Passing-Bablok regression, and Lin correlation coefficients. Bland-Altman analysis demonstrated that the mean bias was >± 25 nmol/L for all 3 candidate tests in comparison to serum LC-MS/MS concentrations. The 95% CIs for the mean bias did not include zero, further supporting the presence of significant bias among methods. Additionally, all 3 tests had poor agreement with serum LC-MS/MS concentrations when analyzed by Lin correlation coefficient analysis, and bias between methods was further characterized by Passing-Bablok analysis. Based on these results, none of these 3 tests is recommended as an alternative to LC-MS/MS testing for 25D measurement in cats.

Fecal identification markers impact the feline fecal microbiota.

Fecal diagnostics are a mainstay of feline medicine, and fecal identification markers help to distinguish individuals in a multi-cat environment. However, the impact of identification markers on the fecal microbiota are unknown. Given the increased interest in using microbiota endpoints to inform diagnosis and treatment, the objective of this study was to examine the effects of orally supplemented glitter and crayon shavings on the feline fecal microbiota (amplicon sequencing of 16S rRNA gene V4 region). Fecal samples were collected daily from six adult cats that were randomized to receive oral supplementation with either glitter or crayon for two weeks, with a two-week washout before receiving the second marker. No adverse effects in response to marker supplementation were seen for any cat, and both markers were readily identifiable in the feces. Microbiota analysis revealed idiosyncratic responses to fecal markers, where changes in community structure in response to glitter or crayon could not be readily discerned. Given these findings, it is not recommended to administered glitter or crayon shavings as a fecal marker when microbiome endpoints are used, however their clinical use with other diagnostics should still be considered.

Physical activity is associated with increased resting-state functional connectivity in networks predictive of cognitive decline in clinically unimpaired older adults.

Introduction: Physical activity (PA) promotes resilience with respect to cognitive decline, although the underlying mechanisms are not well understood. We examined the associations between objectively measured PA and resting-state functional connectivity magnetic resonance imaging (rs-fcMRI) across seven anatomically distributed neural networks. Methods: rs-fcMRI, amyloid beta (Aß) positron emission tomography (PET), PA (steps/day × 1 week), and longitudinal cognitive (Preclinical Alzheimer's Cognitive Composite) data from 167 cognitively unimpaired adults (ages 63 to 90) were used. We used linear and linear mixed-effects regression models to examine the associations between baseline PA and baseline network connectivity and between PA, network connectivity, and longitudinal cognitive performance. Results: Higher PA was associated selectively with greater connectivity in three networks previously associated with cognitive decline (default, salience, left control). This association with network connectivity accounted for a modest portion of PA's effects on Aß-related cognitive decline. Discussion: Although other mechanisms are likely present, PA may promote resilience with respect to Aß-related cognitive decline, partly by increasing connectivity in a subset of cognitive networks.

Ribodysgenesis: sudden genome instability in the yeast Saccharomyces cerevisiae arising from RNase H2 cleavage at genomic-embedded ribonucleotides.

Ribonucleotides can be incorporated into DNA during replication by the replicative DNA polymerases. These aberrant DNA subunits are efficiently recognized and removed by Ribonucleotide Excision Repair, which is initiated by the heterotrimeric enzyme RNase H2. While RNase H2 is essential in higher eukaryotes, the yeast Saccharomyces cerevisiae can survive without RNase H2 enzyme, although the genome undergoes mutation, recombination and other genome instability events at an increased rate. Although RNase H2 can be considered as a protector of the genome from the deleterious events that can ensue from recognition and removal of embedded ribonucleotides, under conditions of high ribonucleotide incorporation and retention in the genome in a RNase H2-negative strain, sudden introduction of active RNase H2 causes massive DNA breaks and genome instability in a condition which we term 'ribodysgenesis'. The DNA breaks and genome instability arise solely from RNase H2 cleavage directed to the ribonucleotide-containing genome. Survivors of ribodysgenesis have massive loss of heterozygosity events stemming from recombinogenic lesions on the ribonucleotide-containing DNA, with increases of over 1000X from wild-type. DNA breaks are produced over one to two divisions and subsequently cells adapt to RNase H2 and ribonucleotides in the genome and grow with normal levels of genome instability.

Postinjury Engagement With the Police and Access to Care Among Victims of Violent Street Crime: Does Criminal History Matter?

This study examines whether victims of violent street crimes who are known to the police as past offenders, when compared with victims with no arrest history, have different outcomes related to receipt of victim and health-related services, while taking into consideration whether or not police responded to the victimization incident. The sample is comprised of 103 men and women between the age of 18 and 40 living in one Mid-Atlantic city who were victims of street violence within the year before study recruitment. Logistic regression was used to assess the impact of police response to the victimization incident on receipt of victim services, and receipt of victim services on engagement with counseling and mental health services. The results show that prior arrests were not associated with receipt of services. However, having police officers respond to the victimization was associated with higher odds of receiving victim services, and in turn, victim services were associated with receiving mental health treatment. Police response appears to set victims on a path to accessing services. Although the number of arrests was not associated with service receipt, a small percentage of victims who did not receive services stated they were reluctant to cooperate with the police, thus limiting their opportunity for victim services. Because most victims who did not access victim services did not know that they existed, policies that promote more knowledge of and initial engagement with victim services could improve access to needed health and mental health services.

[Teletherapy after cochlear implantation during the COVID-19 pandemic]. / Teletherapie nach Cochleaimplantation in der COVID-19-Pandemie.

BACKGROUND: Due to the COVID-19 pandemic, digitalization in healthcare grew rapidly. Auditory training after cochlear implantation usually takes place face-to-face but social distancing interferes with this therapeutic approach. MATERIALS AND METHODS: In follow-up treatment, 42 adult cochlear implant (CI) users aged 53.8 (±15.6) years received video therapy 1 x/week for 5 weeks on a certified platform. After each therapy session, the technical process and therapeutic content were assessed. At the end of the study, usability and the relationship between therapist and patient were evaluated by patients and therapists using the System Usability Scale (SUS), a final questionnaire and by the Skala Therapeutische Allianz - Revised (STA-R). Furthermore, a cost-benefit analysis was done. RESULTS: Usability for both users was high (87.97 versus 93.0). Despite the lack of personal contact, therapeutic alliance was highly appreciated by patients and therapists (87.8% versus 84.8%). The main advantages for the patients were reductions in time and costs. In contrast, the rehabilitation center faced higher costs initially due to the longer time therapists needed to prepare the lessons. Technical problems had to be solved in > 75% of the first sessions but did not bother training thereafter. In total, 47.6% of the patients believe that teletherapy can completely fulfill their therapeutic needs. CONCLUSION: Video therapy has been judged as a useful tool by all users and the majority wants to continue. However, it remains questionable whether the therapist-patient relationship can be sufficiently maintained over a longer period and whether online therapy is as effective as face-to-face therapy.

Association of Digital Clock Drawing With PET Amyloid and Tau Pathology in Normal Older Adults.

OBJECTIVE: To determine whether a digital clock-drawing test, DCTclock, improves upon standard cognitive assessments for discriminating diagnostic groups and for detecting biomarker evidence of amyloid and tau pathology in clinically normal older adults (CN). METHODS: Participants from the Harvard Aging Brain Study and the PET laboratory at Massachusetts General Hospital were recruited to undergo the DCTclock, standard neuropsychological assessments including the Preclinical Alzheimer Cognitive Composite (PACC), and amyloid/tau PET imaging. Receiver operating curve analyses were used to assess diagnostic and biomarker discriminability. Logistic regression and partial correlations were used to assess DCTclock performance in relation to PACC and PET biomarkers. RESULTS: A total of 300 participants were studied. Among the 264 CN participants, 143 had amyloid and tau PET imaging (Clinical Dementia Rating [CDR] 0, Mini-Mental State Examination [MMSE] 28.9 ± 1.2). An additional 36 participants with a diagnosis of mild cognitive impairment or early Alzheimer dementia (CDR 0.5, MMSE 25.2 ± 3.9) were added to assess diagnostic discriminability. DCTclock showed excellent discrimination between diagnostic groups (area under the receiver operating characteristic curve 0.86). Among CN participants with biomarkers, the DCTclock summary score and spatial reasoning subscores were associated with greater amyloid and tau burden and showed better discrimination (Cohen d = 0.76) between Aß± groups than the PACC (d = 0.30). CONCLUSION: DCTclock discriminates between diagnostic groups and improves upon traditional cognitive tests for detecting biomarkers of amyloid and tau pathology in CN older adults. The validation of such digitized measures has the potential of providing an efficient tool for detecting early cognitive changes along the AD trajectory. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that DCTclock results were associated with amyloid and tau burden in CN older adults.

Intrachromosomal Recombination in Yeast.

Spontaneous and induced mitotic recombinations are driven by lesions such as single-strand nicks and gaps and double-strand breaks in the genome. For regions of the genome that are not repetitive, spontaneous recombination rates are too low to be detected by simple screening and require reporters where a recombination product can be selected. This chapter describes commonly used types of reporters where a gene is duplicated as direct repeats and both copies are mutated with different mutations, rendering the cell defective for the gene and auxotrophic for the gene product. Recombination between the two defective copies can result in a wild-type gene and a prototrophic phenotype for the cell. Methods to use these types of reporters to determine recombination rates between the two gene copies are described, and their use in monitoring both increased and decreased recombinations is discussed.

Developmental stages in microbiota, bile acids, and clostridial species in healthy puppies.

BACKGROUND: The fecal microbiota, fecal bile acid concentrations, and abundance of Clostridium perfringens and Clostridium difficile are altered in acute and chronic gastrointestinal disease in adult dogs. However, less is known in young puppies. HYPOTHESIS/OBJECTIVES: To determine composition of the fecal microbiota, assess development of fecal bile acid profiles, and determine the abundance of Clostridial species in puppies, young adult dogs, and adult dogs. ANIMALS: Healthy puppies from a whelping kennel (n = 53) and healthy client-owned dogs <1 year old (n = 20) were separated into 6 age groups, then compared to client-owned dogs over 1 year of age (n = 13). METHODS: Prospective observational study. Naturally voided fecal samples were analyzed by quantitative polymerase chain reaction to measure bacterial abundances. Fecal bile acids were quantified using gas chromatography-mass spectrometry. RESULTS: Puppies up to 5 to 6 weeks of age had increased Dysbiosis Index (median [min-max]: 5.39 [1.32-8.6], P < .001), increased abundance of C. difficile (4.1 [0.01-4.85] log DNA, P < .001), decreased secondary bile acid concentrations (0.61 [0.28-5.06] µg/mg, P = .006), and decreased abundance of C. hiranonis (0.84 [0.01-6.71], P = .005) compared to adult dogs (-4.62 [-8.36 to -0.61], 0.01 [0.01-0.01], 4.12 [0.32-8.94], and 6.02 [5.06-7.00], respectively). Secondary bile acid concentration positively correlated with C. hiranonis abundance (ρ = 0.77; P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: The increase in secondary bile acids and simultaneous decrease of C. difficile and C. perfringens after 5 to 6 weeks of age warrants further investigation into regulatory impacts that secondary bile acids could have on clostridial species in dogs.

Associations of Physical Activity and ß-Amyloid With Longitudinal Cognition and Neurodegeneration in Clinically Normal Older Adults.

IMPORTANCE: In the absence of disease-modifying therapies for Alzheimer disease, there is a critical need to identify modifiable risk factors that may delay the progression of Alzheimer disease. OBJECTIVE: To examine whether physical activity moderates the association of ß-amyloid (Aß) burden with longitudinal cognitive decline and neurodegeneration in clinically normal individuals and to examine whether these associations are independent of vascular risk. DESIGN, SETTING, AND PARTICIPANTS: This longitudinal observational study included clinically normal participants from the Harvard Aging Brain Study. Participants were required to have baseline Aß positron emission tomography data, baseline medical data to quantify vascular risk, and longitudinal neuropsychological and structural magnetic resonance imaging data. Data were collected from April 2010 to June 2018. Data were analyzed from August to December 2018. MAIN OUTCOMES AND MEASURES: Baseline physical activity was quantified with a pedometer (mean steps per day). Baseline Aß burden was measured with carbon 11-labeled Pittsburgh Compound B positron emission tomography. Cognition was measured annually with the Preclinical Alzheimer Cognitive Composite (PACC; median [interquartile range] follow-up, 6.0 [4.3-6.3] years). Neurodegeneration was assessed with longitudinal structural magnetic resonance imaging (2 to 5 scans per participant; median [interquartile range] follow-up, 4.5 [3.0-5.0] years), with a focus on total gray matter volume and regional cortical thickness. Physical activity and Aß burden were examined as interactive predictors of PACC decline and volume loss in separate linear mixed models, adjusting for age, sex, education, apolipoprotein E ε4 status, and, where appropriate, intracranial volume. Secondary models adjusted for vascular risk and its interaction with Aß burden. RESULTS: Of the 182 included participants, 103 (56.6%) were female, and the mean (SD) age was 73.4 (6.2) years. In models examining PACC decline and volume loss, there was a significant interaction of physical activity with Aß burden, such that greater physical activity was associated with slower Aß-related cognitive decline (ß, 0.03; 95% CI, 0.02-0.05; P < .001) and volume loss (ß, 482.07; 95% CI, 189.40-774.74; P = .002). Adjusting for vascular risk did not alter these associations. In these models, lower vascular risk was independently associated with slower Aß-related PACC decline (ß, -0.04; 95% CI, -0.06 to -0.02; P < .001) and volume loss (ß, -483.41; 95% CI, -855.63 to -111.20; P = .01). CONCLUSIONS AND RELEVANCE: Greater physical activity and lower vascular risk independently attenuated the negative association of Aß burden with cognitive decline and neurodegeneration in asymptomatic individuals. These findings suggest that engaging in physical activity and lowering vascular risk may have additive protective effects on delaying the progression of Alzheimer disease.

Genome instability consequences of RNase H2 Aicardi-Goutières syndrome alleles.

The RNase H2 complex is a conserved heterotrimeric enzyme that degrades RNA:DNA hybrids and promotes excision of rNMPs misincorporated during DNA replication. Failure to remove ribonucleotides from DNA leads to genomic instability in yeast and humans. The monogenic Aicardi-Goutières syndrome (AGS) results from mutation in one of several genes, among which are those encoding the RNase H2 subunits. The complete cellular and genomic consequences of RNASEH2 mutations and the precise connection to disease remain unclear. To learn more about the effect of RNASEH2 mutations on the cell, we used yeast as a model of AGS disease. We have generated yeast strains bearing AGS-associated mutations in RNASEH2 genes. There is a range of disease presentation in patients bearing these RNASEH2 variants. Here we report on in vivo phenotypes of genomic instability, including mutation and recombination rates, and synthetic gene interactions. These phenotypes provide insight into molecular consequences of RNASEH2 mutations, and lay the groundwork for further study of genomic instability as a contributing factor to AGS disease.

Guidelines for DNA recombination and repair studies: Mechanistic assays of DNA repair processes.

Genomes are constantly in flux, undergoing changes due to recombination, repair and mutagenesis. In vivo, many of such changes are studies using reporters for specific types of changes, or through cytological studies that detect changes at the single-cell level. Single molecule assays, which are reviewed here, can detect transient intermediates and dynamics of events. Biochemical assays allow detailed investigation of the DNA and protein activities of each step in a repair, recombination or mutagenesis event. Each type of assay is a powerful tool but each comes with its particular advantages and limitations. Here the most commonly used assays are reviewed, discussed, and presented as the guidelines for future studies.

Guidelines for DNA recombination and repair studies: Cellular assays of DNA repair pathways.

Understanding the plasticity of genomes has been greatly aided by assays for recombination, repair and mutagenesis. These assays have been developed in microbial systems that provide the advantages of genetic and molecular reporters that can readily be manipulated. Cellular assays comprise genetic, molecular, and cytological reporters. The assays are powerful tools but each comes with its particular advantages and limitations. Here the most commonly used assays are reviewed, discussed, and presented as the guidelines for future studies.

Vascular Risk and ß-Amyloid Are Synergistically Associated with Cortical Tau.

OBJECTIVE: Neuropathological studies have demonstrated that cerebrovascular disease and Alzheimer disease (AD) pathology frequently co-occur in older adults. The extent to which cerebrovascular disease influences the progression of AD pathology remains unclear. Leveraging newly available positron emission tomography (PET) imaging, we examined whether a well-validated measure of systemic vascular risk and ß-amyloid (Aß) burden have an interactive association with regional tau burden. METHODS: Vascular risk was quantified at baseline in 152 clinically normal older adults (mean age = 73.5 ± 6.1 years) with the office-based Framingham Heart Study cardiovascular disease risk algorithm (FHS-CVD). We acquired Aß (11 C-Pittsburgh compound B) and tau (18 F-flortaucipir) PET imaging on the same participants. Aß PET was performed at baseline; tau PET was acquired on average 2.98 ± 1.1 years later. Tau was measured in the entorhinal cortex (EC), an early site of tau deposition, and in the inferior temporal cortex (ITC), an early site of neocortical tau accumulation associated with AD. Linear regression models examined FHS-CVD and Aß as interactive predictors of tau deposition, adjusting for age, sex, APOE ε4 status, and the time interval between baseline and the tau PET scan. RESULTS: We observed a significant interaction between FHS-CVD and Aß burden on subsequently measured ITC tau (p < 0.001), whereby combined higher FHS-CVD and elevated Aß burden was associated with increased tau. The interaction was not significant for EC tau (p = 0.16). INTERPRETATION: Elevated vascular risk may influence tau burden when coupled with high Aß burden. These results suggest a potential link between vascular risk and tau pathology in preclinical AD. Ann Neurol 2019; 1-8 ANN NEUROL 2019;85:272-279.

Genomic Copy-Number Loss Is Rescued by Self-Limiting Production of DNA Circles.

Copy-number changes generate phenotypic variability in health and disease. Whether organisms protect against copy-number changes is largely unknown. Here, we show that Saccharomyces cerevisiae monitors the copy number of its ribosomal DNA (rDNA) and rapidly responds to copy-number loss with the clonal amplification of extrachromosomal rDNA circles (ERCs) from chromosomal repeats. ERC formation is replicative, separable from repeat loss, and reaches a dynamic steady state that responds to the addition of exogenous rDNA copies. ERC levels are also modulated by RNAPI activity and diet, suggesting that rDNA copy number is calibrated against the cellular demand for rRNA. Last, we show that ERCs reinsert into the genome in a dosage-dependent manner, indicating that they provide a reservoir for ultimately increasing rDNA array length. Our results reveal a DNA-based mechanism for rapidly restoring copy number in response to catastrophic gene loss that shares fundamental features with unscheduled copy-number amplifications in cancer cells.

Interactive Associations of Vascular Risk and ß-Amyloid Burden With Cognitive Decline in Clinically Normal Elderly Individuals: Findings From the Harvard Aging Brain Study.

Importance: Identifying asymptomatic individuals at high risk of impending cognitive decline because of Alzheimer disease is crucial for successful prevention of dementia. Vascular risk and ß-amyloid (Aß) pathology commonly co-occur in older adults and are significant causes of cognitive impairment. Objective: To determine whether vascular risk and Aß burden act additively or synergistically to promote cognitive decline in clinically normal older adults; and, secondarily, to evaluate the unique influence of vascular risk on prospective cognitive decline beyond that of commonly used imaging biomarkers, including Aß burden, hippocampal volume, fludeoxyglucose F18-labeled (FDG) positron emission tomography (PET), and white matter hyperintensities, a marker of cerebrovascular disease. Design, Setting, and Participants: In this longitudinal observational study, we examined clinically normal older adults from the Harvard Aging Brain Study. Participants were required to have baseline imaging data (FDG-PET, Aß-PET, and magnetic resonance imaging), baseline medical data to quantify vascular risk, and at least 1 follow-up neuropsychological visit. Data collection began in 2010 and is ongoing. Data analysis was performed on data collected between 2010 and 2017. Main Outcomes and Measures: Vascular risk was quantified using the Framingham Heart Study general cardiovascular disease (FHS-CVD) risk score. We measured Aß burden with Pittsburgh Compound-B PET. Cognition was measured annually with the Preclinical Alzheimer Cognitive Composite. Models were corrected for baseline age, sex, years of education, and apolipoprotein E ε4 status. Results: Of the 223 participants, 130 (58.3%) were women. The mean (SD) age was 73.7 (6.0) years, and the mean (SD) follow-up time was 3.7 (1.2) years. Faster cognitive decline was associated with both a higher FHS-CVD risk score (ß = -0.064; 95% CI, -0.094 to -0.033; P < .001) and higher Aß burden (ß = -0.058; 95% CI, -0.079 to -0.037; P < .001). The interaction of the FHS-CVD risk score and Aß burden with time was significant (ß = -0.040, 95% CI, -0.062 to -0.018; P < .001), suggesting a synergistic effect. The FHS-CVD risk score remained robustly associated with prospective cognitive decline (ß = -0.055; 95% CI, -0.086 to -0.024; P < .001), even after adjustment for Aß burden, hippocampal volume, FDG-PET uptake, and white matter hyperintensities. Conclusions and Relevance: In this study, vascular risk was associated with prospective cognitive decline in clinically normal older adults, both alone and synergistically with Aß burden. Vascular risk may complement imaging biomarkers in assessing risk of prospective cognitive decline in preclinical Alzheimer disease.

Genome instabilities arising from ribonucleotides in DNA.

Genomic DNA is transiently contaminated with ribonucleotide residues during the process of DNA replication through misincorporation by the replicative DNA polymerases α, δ and ε, and by the normal replication process on the lagging strand, which uses RNA primers. These ribonucleotides are efficiently removed during replication by RNase H enzymes and the lagging strand synthesis machinery. However, when ribonucleotides remain in DNA they can distort the DNA helix, affect machineries for DNA replication, transcription and repair, and can stimulate genomic instabilities which are manifest as increased mutation, recombination and chromosome alterations. The genomic instabilities associated with embedded ribonucleotides are considered here, along with a discussion of the origin of the lesions that stimulate particular classes of instabilities.