Intraoperative electrocochleographic characteristics of auditory neuropathy spectrum disorder in cochlear implant subjects

Auditory neuropathy spectrum disorder (ANSD) is characterized by an apparent discrepancy between measures of cochlear and neural function based on auditory brainstem response (ABR) testing. Clinical indicators of ANSD are a present cochlear microphonic (CM) with small or absent wave V. Many identified ANSD patients have speech impairment severe enough that cochlear implantation (CI) is indicated. To better understand the cochleae identified with ANSD that lead to a CI, we performed intraoperative round window electrocochleography (ECochG) to tone bursts in children (n = 167) and adults (n = 163). Magnitudes of the responses to tones of different frequencies were summed to measure the “total response” (ECochG-TR), a metric often dominated by hair cell activity, and auditory nerve activity was estimated visually from the compound action potential (CAP) and auditory nerve neurophonic (ANN) as a ranked “Nerve Score”. Subjects identified as ANSD (45 ears in children, 3 in adults) had higher values of ECochG-TR than adult and pediatric subjects also receiving CIs not identified as ANSD. However, nerve scores of the ANSD group were similar to the other cohorts, although dominated by the ANN to low frequencies more than in the non-ANSD groups. To high frequencies, the common morphology of ANSD cases was a large CM and summating potential, and small or absent CAP. Common morphologies in other groups were either only a CM, or a combination of CM and CAP. These results indicate that responses to high frequencies, derived primarily from hair cells, are the main source of the CM used to evaluate ANSD in the clinical setting. However, the clinical tests do not capture the wide range of neural activity seen to low frequency sounds

The fundamental equation of eddy covariance and its application in flux measurements

A fundamental equation of eddy covariance (FQEC) is derived that allows the net ecosystem exchange (NEE) N̅s of a specified atmospheric constituent s to be measured with the constraint of conservation of any other atmospheric constituent (e.g. N2, argon, or dry air). It is shown that if the condition │N̅s│ ˃˃ │X̅s│ │N̅co2│is true, the conservation of mass can be applied with the assumption of no net ecosystem source or sink of dry air and the FQEC is reduced to the following equation and its approximation for horizontally homogeneous mass fluxes: N̅s = c̅dw’X’s│h + ∫h0 c̅d(z) ∂Xs/∂t dz + ∫h0 [X̅s (z)- X̅s (h)] ∂̅c̅d̅/∂t dz = c̅d̅(h) {w̅’X̅’s│h + ∫h0 ∂Xs/∂t dz}. Here w is vertical velocity, c molar density, t time, h eddy flux measurement height, z vertical distance and Xs= cs/cd molar mixing ratio relative to dry air. Subscripts s, d and CO2 are for the specified constituent, dry air and carbon dioxide, respectively. Primes and overbars refer to turbulent fluctuations and time averages, respectively. This equation and its approximation are derived for non-steady state conditions that build on the steady-state theory of Webb, Pearman and Leuning (WPL; Webb et al., 1980. Quart. J. R. Meteorol. Soc. 106, 85–100), theory that is widely used to calculate the eddy fluxes of CO2 and other trace gases. The original WPL constraint of no vertical flux of dry air across the EC measurement plane, which is valid only for steady-state conditions, is replaced with the requirement of no net ecosystem source or sink of dry air for non-steady state conditions. This replacement does not affect the ‘eddy flux’ term c̅d̅w̅’X̅’s s but requires the change in storage to be calculated as the ‘effective change in storage’ as follows: ∫h0 ∂̅c̅s̅/ ∂̅t̅ dz – X̅s(h) ∫h0 ∂̅c̅d̅/∂t dz = ∫h0 c̅d̅ (z) - ∂Xs/∂t dz + ∫h0 [X̅s (z)- X̅s (h)] ∂̅c̅d̅/∂t dz= c̅d (h) ∫h0 ∂Xs/∂t dz. Without doing so, significant diurnal and seasonal biases may occur. We demonstrate that the effective change in storage can be estimated accurately with a properly designed profile of mixing ratio measurements made at multiple heights. However further simplification by using a single measurement at the EC instrumentation height is shown to produce substantial biases. It is emphasized that an adequately designed profile system for measuring the effective change in storage in proper units is as important as the eddy flux term for determining NEE

The fundamental equation of eddy covariance and its application in flux measurements

A fundamental equation of eddy covariance (FQEC) is derived that allows the net ecosystem exchange (NEE) N̅s of a specified atmospheric constituent s to be measured with the constraint of conservation of any other atmospheric constituent (e.g. N2, argon, or dry air). It is shown that if the condition │N̅s│ ˃˃ │X̅s│ │N̅co2│is true, the conservation of mass can be applied with the assumption of no net ecosystem source or sink of dry air and the FQEC is reduced to the following equation and its approximation for horizontally homogeneous mass fluxes: N̅s = c̅dw’X’s│h + ∫h0 c̅d(z) ∂Xs/∂t dz + ∫h0 [X̅s (z)- X̅s (h)] ∂̅c̅d̅/∂t dz = c̅d̅(h) {w̅’X̅’s│h + ∫h0 ∂Xs/∂t dz}. Here w is vertical velocity, c molar density, t time, h eddy flux measurement height, z vertical distance and Xs= cs/cd molar mixing ratio relative to dry air. Subscripts s, d and CO2 are for the specified constituent, dry air and carbon dioxide, respectively. Primes and overbars refer to turbulent fluctuations and time averages, respectively. This equation and its approximation are derived for non-steady state conditions that build on the steady-state theory of Webb, Pearman and Leuning (WPL; Webb et al., 1980. Quart. J. R. Meteorol. Soc. 106, 85–100), theory that is widely used to calculate the eddy fluxes of CO2 and other trace gases. The original WPL constraint of no vertical flux of dry air across the EC measurement plane, which is valid only for steady-state conditions, is replaced with the requirement of no net ecosystem source or sink of dry air for non-steady state conditions. This replacement does not affect the ‘eddy flux’ term c̅d̅w̅’X̅’s s but requires the change in storage to be calculated as the ‘effective change in storage’ as follows: ∫h0 ∂̅c̅s̅/ ∂̅t̅ dz – X̅s(h) ∫h0 ∂̅c̅d̅/∂t dz = ∫h0 c̅d̅ (z) - ∂Xs/∂t dz + ∫h0 [X̅s (z)- X̅s (h)] ∂̅c̅d̅/∂t dz= c̅d (h) ∫h0 ∂Xs/∂t dz. Without doing so, significant diurnal and seasonal biases may occur. We demonstrate that the effective change in storage can be estimated accurately with a properly designed profile of mixing ratio measurements made at multiple heights. However further simplification by using a single measurement at the EC instrumentation height is shown to produce substantial biases. It is emphasized that an adequately designed profile system for measuring the effective change in storage in proper units is as important as the eddy flux term for determining NEE

Multihospital Outbreak of Clostridium difficile Infection, Cleveland, Ohio, USA

To determine whether a multihospital Clostridium difficile outbreak was associated with epidemic strains and whether use of particular fluoroquinolones was associated with increased infection rates, we cultured feces from C. difficile–infected patients. Use of fluoroquionolones with enhanced antianaerobic activity was not associated with increased infection rates

Assessment of cochlear synaptopathy by electrocochleography to low frequencies in a preclinical model and human subjects

Cochlear synaptopathy is the loss of synapses between the inner hair cells and the auditory nerve despite survival of sensory hair cells. The findings of extensive cochlear synaptopathy in animals after moderate noise exposures challenged the long-held view that hair cells are the cochlear elements most sensitive to insults that lead to hearing loss. However, cochlear synaptopathy has been difficult to identify in humans. We applied novel algorithms to determine hair cell and neural contributions to electrocochleographic (ECochG) recordings from the round window of animal and human subjects. Gerbils with normal hearing provided training and test sets for a deep learning algorithm to detect the presence of neural responses to low frequency sounds, and an analytic model was used to quantify the proportion of neural and hair cell contributions to the ECochG response. The capacity to detect cochlear synaptopathy was validated in normal hearing and noise-exposed animals by using neurotoxins to reduce or eliminate the neural contributions. When the analytical methods were applied to human surgical subjects with access to the round window, the neural contribution resembled the partial cochlear synaptopathy present after neurotoxin application in animals. This result demonstrates the presence of viable hair cells not connected to auditory nerve fibers in human subjects with substantial hearing loss and indicates that efforts to regenerate nerve fibers may find a ready cochlear substrate for innervation and resumption of function

Lessons Learned from the First 10 Years of the Oaks and Prairies Joint Venture’s Grassland Restoration Incentive Program (GRIP)

The Oaks and Prairies Joint Venture (OPJV) was formed in 2008 as a public-private partnership of agencies and organizations working across jurisdictional boundaries in portions of Texas and Oklahoma, USA. The OPJV’s major focus is reversing declines of bird populations by supporting strategic habitat conservation (biological planning, conservation design, conservation delivery, mission-based monitoring, and assumption-driven research) for northern bobwhite (Colinus virginianus), grasslandobligate species, and their respective habitats. Our objective for this paper is to document and share a decade of lessons learned in developing a partnership-based native grassland conservation program to meet grassland bird conservation targets. We share lessons learned about how to manage partnership-based, large-scale habitat incentive programs to better target project locations and habitat practice types. To establish initial shared purpose, OPJV partners drew from population and habitat objectives in various state, national, and international bird conservation plans, stepped down to ecoregion levels, to establish the OPJV Grassland Bird Conservation Business Plan. The plan has 4 strategies directly contributing to the achievement of OPJV grassland bird biological objectives that are directly supported by OPJV staff or resources (or both). The overall objective for 2015–2025 was 619,978 ha (1,532,000 acres) improved within 40 focal counties, representing 1/3 of all counties in the OPJV. Our main strategy was to provide financial incentives through the OPJV Grassland Restoration Incentive Program (GRIP) to private landowners for conducting beneficial grassland bird habitat management practices. Since inception in 2013, GRIP has treated over 44,515 ha (110,000 acres) on private lands in Texas and Oklahoma, with the goal of maintaining highquality grassland bird habitat on treated hectares for ≥5 years. In 2017, OPJV partners working with USDA Natural Resources Conservation Service, began a 5-year, $6.1 million partnership to provide additional technical and financial assistance to private landowners interested in grassland conservation through the Regional Conservation Partnership Program (RCPP). A project scoring system was designed to strategically encourage individual projects to include prescribed fire—one of the lowest cost practices per hectare—as a recurring practice to maintain program-achieved grassland improvements. Post-inception of the RCPP, the area treated with prescribed fire increased from approximately 809 ha (2,000 acres)/year to 3,237 ha (8,000 acres)/ year, while maintaining average annual hectares of all other beneficial practices. Beginning in 2013, bird point count surveys were conducted annually to monitor northern bobwhite and grassland bird populations, including a subset of points under the National Bobwhite Conservation Initiative (NBCI) Coordinated Implementation Plan. To date, nearly 25,000 individual point counts have been performed in Texas (n = 20,111) and Oklahoma (n = 4,558). Working together, OPJV partners have made significant progress toward meeting grassland bird habitat and population objectives, while tracking progress and improving methods. However, there is still considerable work ahead

‘‘Epic ear defence’’—a game to educate children on the risks of noise-related hearing loss

Hearing loss resulting from overexposure to entertainment-related sounds is a modern concern. ‘‘Epic Ear Defence’’ places the player in the three-dimensional environment of the ear canal and challenges the player to defend the ear from various noises, to delay the onset of noise-related hearing loss.Chevron Australia provided funding through their Community Donations Schemehttp://www.liebertpub.com/g4ham201

Comparison of Skeletal Effects of Ovariectomy Versus Chemically Induced Ovarian Failure in Mice

Bone loss associated with menopause leads to an increase in skeletal fragility and fracture risk. Relevant animal models can be useful for evaluating the impact of ovarian failure on bone loss. A chemically induced model of menopause in which mice gradually undergo ovarian failure yet retain residual ovarian tissue has been developed using the chemical 4-vinylcyclohexene diepoxide (VCD). This study was designed to compare skeletal effects of VCD-induced ovarian failure to those associated with ovariectomy (OVX). Young (28 day) C57Bl/6Hsd female mice were dosed daily with vehicle or VCD (160 mg/kg/d, IP) for 15 days (n = 6–7/group) and monitored by vaginal cytology for ovarian failure. At the mean age of VCD-induced ovarian failure (∼6 wk after onset of dosing), a different group of mice was ovariectomized (OVX, n = 8). Spine BMD (SpBMD) was measured by DXA for 3 mo after ovarian failure and OVX. Mice were killed ∼5 mo after ovarian failure or OVX, and bone architecture was evaluated by μCT ex vivo. In OVX mice, SpBMD was lower than controls 1 mo after OVX, whereas in VCD-treated mice, SpBMD was not lower than controls until 2.9 mo after ovarian failure (p < 0.05). Both VCD-induced ovarian failure and OVX led to pronounced deterioration of trabecular bone architecture, with slightly greater effects in OVX mice. At the femoral diaphysis, cortical bone area and thickness did not differ between VCD mice and controls but were decreased in OVX compared with both groups (p < 0.05). Circulating androstenedione levels were preserved in VCD-treated mice but reduced in OVX mice relative to controls (p < 0.001). These findings support that (1) VCD-induced ovarian failure leads to trabecular bone deterioration, (2) bone loss is attenuated by residual ovarian tissue, particularly in diaphyseal cortical bone, and (3) the VCD mouse model can be a relevant model for natural menopause in the study of associated bone disorders

The effect of postexercise carbohydrate and protein ingestion on bone metabolism

Purpose To investigate the effect of feeding carbohydrate and protein (CHO+PRO), immediately or 2 h after an exhaustive run, on the bone turnover response in endurance runners. Methods 10 men (age 28±5 y, height 1.74±0.05 m, body mass 69.7±6.3 kg) performed treadmill running at 75%VO2max, until exhaustion, on three occasions. Blood was collected before and immediately, 1, 2, 3, 4 and 24 h post-exercise, for measurement of β-CTX, P1NP, PTH, PO4, ACa and Ca2+. This was a randomised, counterbalanced, placebo-controlled, single-blinded, cross-over study. The three trials were; i) placebo (PLA), PLA solution was ingested immediately and 2 h post-exercise, ii) immediate feeding (IF), CHO+PRO (1.5 g.kgBM-1 dextrose and 0.5 g.kgBM-1 whey) were ingested immediately post-exercise and PLA 2 h post-exercise, and iii) delayed feeding (DF), PLA was ingested immediately post-exercise and CHO+PRO solution 2 h post-exercise. Data were analysed using repeated measures ANOVA and post-hoc Tukey’s HSD. Results At 1 and 2 h post-exercise, β-CTX concentrations were lower in the IF trial than the DF and PLA trials (P≤0.001). At 3 h post-exercise, β-CTX concentrations were higher in the PLA trial than the IF (P≤0.001) and DF trials (P=0.026). At 4 h post-exercise, β-CTX concentrations were lower in the DF trial than the IF (P=0.003) and PLA trials (P≤0.001). At 4 h post-exercise, P1NP was higher in the IF trial than in DF (P=0.026) and PLA trials (P=0.001). At 3 h post-exercise, PTH was higher in the IF trial than the DF trial (P≤0.001). Conclusions Following exhaustive running, immediate ingestion of CHO+PRO may be beneficial, as it decreases bone resorption marker concentrations and increases bone formation marker concentrations; creating a more positive bone turnover balance

INvestigational Vertebroplasty Efficacy and Safety Trial (INVEST): a randomized controlled trial of percutaneous vertebroplasty

Background: The treatment of painful osteoporotic vertebral compression fractures has historically been limited to several weeks of bed rest, anti-inflammatory and analgesic medications, calcitonin injections, or external bracing. Percutaneous vertebroplasty (the injection of bone cement into the fractured vertebral body) is a relatively new procedure used to treat these fractures. There is increasing interest to examine the efficacy and safety of percutaneous vertebroplasty and to study the possibility of a placebo effect or whether the pain relief is from local anesthetics placed directly on the bone during the vertebroplasty procedure. Methods/Designs: Our goal is to test the hypothesis that patients with painful osteoporotic vertebral compression fractures who undergo vertebroplasty have less disability and pain at 1 month than patients who undergo a control intervention. The control intervention is placement of local anesthesia near the fracture, without placement of cement. One hundred sixty-six patients with painful osteoporotic vertebral compression fractures will be recruited over 5 years from US and foreign sites performing the vertebroplasty procedure. We will exclude patients with malignant tumor deposit (multiple myeloma), tumor mass or tumor extension into the epidural space at the level of the fracture. We will randomly assign participants to receive either vertebroplasty or the control intervention. Subjects will complete a battery of validated, standardized measures of pain, functional disability, and health related quality of life at baseline and at post-randomization time points (days 1, 2, 3, and 14, and months 1, 3, 6, and 12). Both subjects and research interviewers performing the follow-up assessments will be blinded to the randomization assignment. Subjects will have a clinic visit at months 1 and 12. Spine X-rays will be obtained at the end of the study (month 12) to determine subsequent fracture rates. Our co-primary outcomes are the modified Roland score and pain numerical rating scale at 1 month. Discussion: Although extensively utilized throughout North America for palliation of pain, vertebroplasty still has not undergone rigorous study. The study outlined above represents the first randomized, controlled study that can account for a placebo effect in the setting of vertebroplasty. Trial Registration: Current Controlled Trials ISRCTN81871888.The source of funding for the study and all authors for this publication was National Institutes of Health (NIH)/National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)