Purpose. To evaluate the clinical applicability of a telemonitoring system: telemetric system for collection and distant surveillance of medical information (TEMEO). Methods. We evaluated 60 patients, applying simultaneously standard Holter ECG and telemonitoring. Two different comparisons were performed: (1) TEMEO ECG with standard 12-lead ECG; (2) TEMEO Holter with standard ECG Holter. Results. We found a very high coincidence rate (99.3%) between TEMEO derived ECGs and standard ECGs. Intraclass correlation coefficient analysis revealed high and significant correlation coefficients regarding average, maximal, and minimal heart rate, % of time in tachycardia, single supraventricular ectopic beats (SVEB), and single and couplets of ventricular ectopic beats (VEB) between Holter ECG and TEMEO derived parameters. Couplets of SVEB were recorded as different by the two monitoring systems, however, with a borderline statistical significance. Conclusions. TEMEO derived ECGs have a very high coincidence rate with standard ECGs. TEMEO patient monitoring provides results that are similar to those derived from a standard Holter ECG. Telemedicine is a relatively new medical trend which incorporates medicine, telecommunications, and information technologies, providing diagnostic workup, treatment, consulting, and training. It enables a patient to get specialized medical advice 24 hours a day independent of his/her location. Telemedicine has been acknowledged in world-leading countries and there are a large number of clinical trials and even some medical journals devoted entirely to this topic. Most of telemonitoring studies however focus on heart failure population –5, aboutExperience with ECG monitoring is still insufficient. Most of the results come from laboratory tests and small clinical trials –16, whilTelemonitoring systems are designed in various ways and adapted to detect and transmit information regarding different clinical parameters. Systems that detect RR intervals and are able to record electrocardiograms (ECG) do not yet have a large clinical application. After performing a literature search we were not able to find a clinical study comparing such a system with the gold standard for ambulatory ECG monitoring—Holter ECG system.Considering this and some existing controversies regarding the usefulness and clinical application of telemonitoring in daily clinical practice we set ourselves the task to evaluate the clinical applicability, patient compliance, and convenience when using a telemonitoring system, telemetric system for collection and distant surveillance of medical information (TEMEO). Two different parameters were compared: (1) TEMEO ECG and standard 12-lead ECG, where only rhythm, heart rate (HR), supraventricular ectopic beats (SVEB), ventricular ectopic beats (VEB), and significant pauses are compared, and (2) comparison between standard Holter ECG and TEMEO Holter regarding average, maximal, and minimal HR, total number of analyzed complexes, percentage of time in tachycardia and single, and couplets and triplets of supraventricular and ventricular ectopic beats.The study was conducted between March and October 2010. We included 60 in-hospital patients, selected from the daily list of patients hospitalized in cardiology departments in our institution. In our opinion, the planned number of patients is sufficient to investigate the functionality and reliability of the system in this pilot study. Inclusion criteria were: every 5th hospitalized patient in a cardiology department, age interval 35–79 years, and presence of cardiovascular disease: coronary artery disease, rhythm-conduction disturbances, congenital or acquired valvular heart disease, and so forth. Exclusion criteria were: implanted pacemaker, resynchronization device or cardioverter-defibrillator; a physical or emotional condition that, according to the investigator, will impede patient participation in the study ; thoracic deformities and lack of informed consent.The design of the study included simultaneous Holter ECG and TEMEO monitoring for at least 20 hours. The protocol of the study included also 5 simultaneous ECG recordings (TEMEO and standard ECG) at baseline, and afterwards at 1st, 2nd, 6th hour and at the end of the monitoring period. All of the manipulations, recordings, and interpretation were performed by the study investigators.Some medical imaging procedures like X-ray examination and echocardiography are performed before using TEMEO system (in terms of easier access to the chest in case of echocardiography).After evaluation of inclusion and exclusion criteria and signing the informed consent form each patient was briefly instructed on how to wear and manipulate (recording ECG) with TEMEO system. The device has only two buttons—one with ON/OFF function and one for ECG record. ECG recording with TEMEO is very easy—stable positioning of the device on the chest, pushing ECG record button for 3 sec, and waiting in this position for 10 seconds. The device was installed and after it a Holter ECG monitor was also added.After completion patients' opinion of the telemonitoring system was registered, as well as any possible reported adverse events.TEMEO system was designed and developed two years ago, as a true wireless telemonitoring solution. The first step was development of its 24 hour ECG Holter-like capability, mobile network transmission, and software for automatic ECG data analysis. The second step was the development of one lead ECG record capability. The next step, which is under development, is blood pressure monitoring capability.TEMEO is an ambulatory patient telemonitoring system, which for the purpose of this study was tested in hospital surroundings.The general conception of TEMEO telemonitoring system is not for it to be a complex and complicated system but to be simple, friendly, mobile, and easy to use. As it is intended to be used by outpatients for a long period of time (weeks), without any medical supervision, it is designed to operate with only short training of patients. Most of the components are designed according to these requirements.The system consists of an elastic chest belt, handheld TEMEO device, and TEMEO electronic center with GSM connection between the device, and the electronic center .An elastic belt placed on the chest under the breasts registers precordial electrical activity of the heart and detects R-R intervals. Two detecting electrodes are built in on the inner surface of the belt, in close contact with the skin. Data from the belt is registered continuously, and is transmitted wirelessly to the mobile handheld device.TEMEO belt could be a source of noise, but is more comfortable, easier to place and remove, and skin friendlier than sticky (standard Holter) electrodes for a long period of time.The handheld device could be worn on the belt or placed in proximity to the patient, for example, during the night period. By means of a GSM network, within 5 minute intervals, recorded data is transmitted (GPRS standard used) to the TEMEO electronic center for further analysis and visualization. GPRS standard for wireless transmission is used because data transfer rate is sufficient; GPRS is a well known and widely used standard supported by Bulgarian mobile operators.This device, due to 3 active (+ one inactive) pin-electrodes placed on the back, has single lead recording capability. When placed vertically at the left sternal border it records lead vector potential similar to a standard aVF. ST-T change analysis is impossible due to minor position and/or angle differences between recordings. The one-lead recording capability does not allow proper diagnosis of ventricular tachycardia.TEMEO ECGs are recorded only on demand, after proper placement and button push, and are transmitted immediately, via GPRS to the electronic center. ECG sampling rate is 100 Hz and the bandwidth used −0.5–40 Hz. Transmission rate over wireless is done with GPRS Class 12 and no compression is employed. At the present moment the system does not have the capability to record continuously the ECG signal 24 hours a day, 7 days a week.The mobile device has also an accelerometer for detection of physical activity  simultaneously with R-R interval detection. The battery is irremovable. A new version with a removable battery is under development.Recorded data is transmitted within 5 minute intervals—that means that every 5 min GPRS connection is established for some seconds, which is feasible, easily achieved, and cheap. The only limitation is GSM coverage, which is 96–98% of the territory of the country. Roaming data transfer is also possible, but it is more expensive. The battery provides 20–24 hours of continuous work (depending on the number of TEMEO ECG records) and 4 hours for charging are required. If there is a loss of signal, a red indicator starts blinking, alerting of the problem. At the moment of system evaluation, if collected data is not transmitted, it is lost due to continuous recording of new data. Now there is an option for 60 minute record buffering.TEMEO electronic center consists of a server with developed software for automatic R-R interval analysis , 18—for The method for beat detection that we use in data analysis is one of the best known in the scientific literature. It has been tested with the MIT-BIH arrhythmia database (sensitivity Se = 99.74% and specificity Sp = 99.65%)  and withThe electronic center is accessible via the internet, from any PC or smartphone with previously installed TEMEO software, with security access to the system. The telemonitoring system has the possibility to alert via SMS the monitoring doctor and the patient in case of significant deviation from normal values .ECG Holter was performed using SYGNA-Lyser, Long Term Ambulatory ECG analysis, Signa Cor Laboratory, Version 5.2.1.3 08.04.2008. SYGNA-Lyser SD ECG Holter device has max 200 Hz sample rate and resolution 8 bit. The recordings were analyzed by an experienced study investigator, blinded for the TEMEO analysis results.Standard 10-second-long 12 lead ECGs were recorded using Sicard 460, Siemens and were analyzed by an experienced study investigator, blinded for the TEMEO ECG results.One-lead 10-second-long TEMEO ECG recordings were registered in supine position, with the handheld device placed vertically at the left sternal border, just under the clavicle (lead vector similar to an aVF), and were compared with corresponding standard ECGs. Comparison of a single-lead ECG with 12-lead ECG was performed, but only for above-mentioned parameters.These two types of ECG recordings (TEMEO ECG and standard ECG) were performed simultaneously at baseline, on the 1st, 2nd, and 6th hour and at the end of the monitoring period.We tested the distribution of continuous variables using the Kolmogorov-Smirnov test. Normally distributed data were presented as mean ± standard deviation (SD), whereas nonnormally distributed data were presented as median and interquartile range (IQR) (the difference between the 25th and 75th percentile). Categorical variables were presented in percentage terms.We analyzed ECG recordings considering 5 parameters: heart rhythm , HR, SVEB, VEB, and significant pauses (>2500 ms). For these parameters we have reported the percentage of coincidence (accordance) between TEMEO and standard Holter ECG systems.P value <0.05 was considered statistically significant. Statistical analysis was performed using SPSS statistical software for Windows, version 13.0.Regarding the monitoring period we have evaluated the following parameters: average, maximal, and minimal HR during the recorded period, total number of analyzed complexes, percentage of time in tachycardia, and single, couplets, and triplets of SVEB and VEB. These parameters were then compared using correlation analysis and calculating the intraclass correlation coefficients. A two-tailed Patients were included in the study after signing an informed consent form. The protocol of the investigation was approved by the Local Ethical Committee. The study was in accordance with the Declaration of Helsinki.Before inclusion we made sure that every patient was aware of the possibility to discontinue the examination without any negative consequences.No adverse events were reported during the study period.In the present study we included 60 patients, 22 (37%) of them female, mean age—58 ± 8 y. The demographic characteristics, risk factor distribution, and medical history of the patients are presented in We have performed 297 standard ECG recordings and 297 TEMEO ECGs (mean number of ECGs per patient—4.95 for each mode of recording) . Due to We found a very high coincidence rate of 99.3% when TEMEO derived ECGs were compared with standard ECGs. We have not registered a coincidence in only 10 comparisons (0.7%). Differences in HR were found in 8 cases—a disparity of 3–6 beats per min, all in ECGs of patients with atrial fibrillation. In all cases with sinus rhythm, it is correctly interpreted in all recorded TEMEO ECG records, even though there were small differences in device position on the chest. In one case, TEMEO ECG was interpreted as atrial fibrillation, when in fact it was atrial flutter with variable AV conduction. In another case, a supraventricular ectopic beat was not registered in TEMEO ECG. In all standard ECGs with atrial fibrillation (8.7% of the recordings), the rhythm was correctly interpreted in the corresponding TEMEO ECG recordings. In 12 standard ECGs with atrial flutter, the rhythm was correctly interpreted in 6 corresponding TEMEO recordings, one of the TEMEO ECGs was interpreted as AF, and in 5 cases the interpretation was atrial tachycardia with 2 : 1 conduction.Twenty TEMEO records had small artifacts; in all cases, however, the quality was good enough for proper determination of all examined parameters.The overall monitoring time with TEMEO system was 61 389 minutes/1023 hours/42.6 days; with the standard Holter ECG it was 72 778 minutes/1213 hours/50.5 days. That means that TEMEO monitoring comprises 84.3% of standard Holter monitoring time. Fifteen patients (25%) were monitored <12 hours with both systems, while the rest of the patients were monitored between 12 and 25 h.In order to compare the telemonitoring device with standard Holter ECG we have analyzed only this time period of the Holter ECG recording during which there is a simultaneous TEMEO recording.The correlations and intraclass correlation coefficients (ICC) between average, maximal, and minimal HR during the recorded period, total number of analyzed complexes, percentage of time in tachycardia, and single and couplet SVEB and VEB evaluated with standard ECG Holter and TEMEO systems are presented in P < 0.001) and statistically significant accordance in the results concerning maximal HR, single SVEB, and single and couplet VEB (P < 0.05). Comparison regarding couplets of SVEB between both systems showed a borderline statistical significance.As could be seen from Maximal and minimal HR determined automatically with the SYGNA-Lyzer system were often interpreted after manual evaluation as erroneously detected due most probably to artifacts. That is the reason why maximal and minimal HR were determined manually by the investigator and as could be seen from There were artifacts recorded with both systems—5% of the time of the Holter ECG recording comprised of artifacts, which was not significantly different from the 6.3% duration of artifact-recording with TEMEO system.During the present study the conditions of wearing the device were not normal—two systems worn together and with multiple ECG recordings (again simultaneous) during the monitoring period. Nevertheless compliance with the system was excellent: none of the patients refused to complete the monitoring period and none of them complained about some discomfort or adverse reaction.Generally the degree of comfort depends on the tightening of the belt: the looser the belt, the more comfortable its wearing, but also more artifact prone. If there is bad contact with the skin, short warning sound signal is present to tighten the belt. TEMEO belt does not disturb normal respiratory excursions during rest and mild and moderate physical activity .TEMEO is not suitable for women with a very large bust due to problems with positioning of the belt. TEMEO system is not water resistant.For the typical situation of ambulatory long-term patient monitoring we have a standard evaluation form for every patient, with 6 questions about the feasibility, comfort, and some comments for the system. Our experience is that 2–4 week monitoring with the system is easy, comfortable, does not restrict their daily activity, and patients are sufficiently motivated to perform it.With the development of electronics and its application in medicine it is possible to transmit and process many vital parameters of the human body. The most important, and in this moment the most interesting, signal for monitoring and analyzing is the ECG signal.ECG telemonitoring enables the control of the health status despite the spatial separation of patient and physician. Cardiac arrhythmias, palpitations of unknown causes, the outcome of antiarrhythmic drug therapy, or interventional ablation therapy can be diagnosed using ECG telemonitoring. The use of telemonitoring for ECG signals has many advantages compared to a classical patients' ECG reading, such as: covering many patients at the same time, covering a large area, real-time information, faster diagnosis, timely therapy, and prevention.There are two widely applicable methods for ECG data recording and analysis: a single-moment ECG capture during patient examination and a 24-hour ECG recording with a later analysis—Holter monitoring . The disadvantage of the 1st method is that it is a single-moment registration and the information is usually not enough to make a diagnosis. The shortcoming of the 2nd method is that it is not possible to intervene immediately, which sometimes can have serious consequences. One possiblesolutionof the problem is continuous loop recorders, even implantable, with their capability for ECG recording and transfer, only during an event.TEMEO system has a potential to combine these two methods of examination in one functional monitoring system with its options for continuous monitoring for long periods of time with multiple event ECG recording. The system is good enough to register episodes of atrial fibrillation, even short standing and “silent”. At this moment, this is the most promising application of this telemonitoring system. TEMEO system is under further investigation with outpatient patients with possible atrial fibrillation. We investigate ambulatory patients with ischemic stroke (>1 month after the acute period) of unknown reason in order to detect any cryptogenic atrial fibrillation responsible for the ischemic incident. At this moment, we have more than 20 patients monitored for a period between 22 and 32 days (mean period 26 days) during their ordinary activity at home and none of them was admitted in hospital during the monitoring period. Some of the patients performed ambulatory rehabilitation program with TEMEO monitoring and even in theses circumstances the compliance was also excellent. TEMEO monitoring time was more than 70% of monitoring period (note that during charging the system is switched off), which in our opinion is a good indicator for excellent compliance.TEMEO system is planned to be user friendly, easy to position on the chest, appropriate for long-period monitoring (even one month). The option with 2-3 or even 12 lead ECG records, requires more electrodes and more reliable contact with the skin than is possible with the TEMEO belt, which, in our opinion, has lots of disadvantages for a long period examination. In most cases, one lead ECG record was quite enough to register most frequent rhythm disturbances.P < 0.05). Comparison regarding couplets of SVEB between both systems showed a borderline statistical significance.In the present study we have evaluated 60 patients, applying simultaneously standard Holter ECG and TEMEO telemonitoring system. Patient compliance during the monitoring period was excellent. We have compared TEMEO derived ECGs with standard ECGs (279 comparisons) and have found a very high coincidence rate of 99.3%. On the basis of intraclass correlation coefficient analysis we then evaluated the level of agreement between Holter ECG derived and TEMEO derived parameters and found high and statistically significant correlation coefficients regarding average, maximal, and minimal HR , % of time in tachycardia, single SVEB, and single and couplet VEB  the monitoring period was shorter. Furthermore, TEMEO monitoring time was 15% shorter than standard Holter surveillance period. This we have corrected for, taking only that period from the Holter ECG recording, during which we have a simultaneous recording from the telemonitoring system.The software of the Holter ECG system SYGNA-Lyzer did not allow us to perform some other comparisons, such as dividing the day and night period and comparing the parameters individually for these periods between the systems .Due to minor position/angle differences of positioning ECG record device, TEMEO is not appropriate for ischaemia detection. Ventricular tachyarrhythmias could not be properly diagnosed with the system due to one-lead ECG recording capability. A 12-lead telemonitoring system is under development.TEMEO telemonitoring system is convenient for the patient, and associated with an excellent compliance. TEMEO derived ECGs have a very high coincidence rate with standard ECGs. TEMEO patient monitoring provides results that are similar to those derived from a standard Holter ECG for some parameters.http://temeo.org/.Any additional data is available on Telemedicine and telemonitoring is a rapidly evolving, contemporary, and promising field in clinical cardiology. ECG telemonitoring is bound to find wide clinical application due to the prevalence of rhythm and conduction disorders and their unpredictable appearance in the daily life of our patients.The ability of 12-lead ECG telemonitoring (a current line of development for TEMEO) will further expand the possibilities for device's application, including ventricular tachycardia detection and ST segment (ischemia) evaluation.


Hearing impairment following cochlear damage due to noise trauma, ototoxicity caused by aminoglycoside antibiotics, or age-related cochlear degeneration was linked to a common pathogenesis involving the formation of reactive oxygen species (ROS). Cochleae are more vulnerable to oxidative stress than other organs because of the high metabolic demands of their mechanosensory hair cells in response to sound stimulation. We recently showed that patients and mice with Huntington's disease (HD) have hearing impairment and that the dysregulated phosphocreatine (PCr)-creatine kinase (CK) system may account for this auditory dysfunction. Given the importance of noninvasive biomarkers and the easy access of hearing tests, the symptom of hearing loss in HD patients may serve as a useful clinical indicator of disease onset and progression of HD. We also showed that dietary creatine supplementation rescued the impaired PCr-CK system and improved the expression of cochlear brain-type creatine kinase (CKB) in HD mice, thereby restoring their hearing. Because creatine is an antioxidant, we postulated that creatine might enhance expression of CKB by reducing oxidative stress. In addition to HD-related hearing impairment, inferior CKB expression and/or an impaired PCr-CK system may also play an important role in other hearing impairments caused by elevated levels of ROS. Most importantly, dietary supplements may be beneficial to patients with these hearing deficiencies. HTT) of HD is ubiquitously expressed, the polyglutamine (polyQ)-expanded mutant Huntingtin protein (Htt) forms nuclear and neutrophil aggregates and preferentially affects the striatum and cerebral cortex. In addition to altered functions in the central nervous system, the expression of mutant Htt was also found in peripheral tissues [(CAG)150) were significantly lower than that of WT mice, suggesting that the impairment of CKB in the cochlea is likely an authentic defect of HD. Interestingly, dietary creatine supplements to HD mice not only rescued the expression of cochlear CKB but also restored the hearing of HD mice  is an autosomal dominant neurodegenerative disorder with onset usually in middle age. Clinical features of HD include uncontrollable motor movements, cognitive impairment, and psychiatric symptoms . Althoug tissues -4, and w tissues , 6. We r tissues , for whiOur findings indicate that the impairment of CKB may account for the cochlear energy deficiency which is likely a primary cause of the observed hearing loss in HD mice . Becauseenergy homeostasis by catalyzing the reversible transfer of high-energy phosphate from phosphocreatine to ADP [It is well known that CK regulates ATP regeneration and e to ADP -11. Tisse to ADP -17. It ie to ADP , 19. None to ADP . Tremende to ADP -31. ConsBesides the inferior expression of CKB, alterations in mitochondrial functions were extensively explored in HD. Well-documented mitochondrial abnormalities including dysregulation of a mitochondrial biogenesis co-activator  [ PGC-1α) , abnorma PGC-1α) , impaire PGC-1α) , 35, and PGC-1α)  were rep PGC-1α) , 38. Int PGC-1α) , suggest PGC-1α) , 41. GivMechanoelectrical transduction of cochlear hair cells in response to acoustic stimuli involves specialized actin-cored microvilli called stereocilia, the deflection of which leads to potassium influx from the endolymph, depolarizes hair cells, and in turn opens voltage-gated calcium channels in cell membranes. The influx of calcium triggers neurotransmitter release from the basal end of the cell into the auditory nerve endings and fires the fiber. This sound reception process in the cochlea requires energy-intense processes to adequately prime the hair bundle movement, for homeostatic calcium regulation, and for potassium recycling to repeat the cycle , 43. BecBesides cochlear hair cells, CKB is also localized in the inner ear spiral ligament, where several ion transport enzymes such as Na, K-ATPase, and carbonic anhydrase are expressed to facilitate potassium ion cycling back to the endolymph -48. AlthAge-related sensorineural hearing loss (SNHL) is the most common sensory deficit in the elderly population  and is cCreatine is a nitrogenous organic acid which is known to increase muscle mass and performance, prevent disease-induced muscle atrophy, and facilitate supplying energy to cells under a reversible catalyzing reaction with CK. Besides its role in energy replenishment, creatine also exerts a strong antioxidant effect by reducing the intra-mitochondrial production of ROS, as well as elevating and preserving the mitochondrial membrane potential . In a noImpaired energy homeostasis recently emerged as an important player in a wide variety of neurodegenerative diseases. Our earlier findings of the functional roles of CKB and the PCr-CK system in hearing loss during HD progression strengthen the importance of energy deficits in HD pathogenesis. Potential applications of dietary creatine supplements and approaches that enhance the expression of CKB for degenerative diseases (including HD) with energy deficiency and SNHL warrant further investigations.


South Korea and surrounding countries in East Asia are believed to have the highest proportion in the world of high frequency hearing loss due to occupational noise exposure, yet there has been limited information published in international journals, and limited information for control of noise in local workplaces beyond strategies from western countries. We exploit medical surveillance information from two worker groups to enhance local knowledge about noise-induced hearing loss and explore the possible importance of shift work to risk.Four-years of hearing data were evaluated for 81 male farm machine factory workers and 371 male firefighters who had successfully completed a health examination and questionnaires for the duration of the study period. The averages of hearing thresholds at 2, 3, and 4 kHz were used as the primary end-point for comparison. Repeat measure analysis adjusted for age, exposure duration and smoking status was used to measure the difference in hearing threshold between the two groups.P < 0.0001) more hearing loss at the baseline of the study than the firefighters in both ears at 2, 3, and 4 kHz, adjusted for age, duration of employment and smoking status. Among those with 10 years of employment, mean losses at these frequencies among the factory workers fell into the impairment range (> 25 dB loss). Firefighters also showed increased losses associated with longer exposure duration, but these were significantly less marked. Losses at lower frequencies (< or = 1 kHz) were negligible in both groups.Noise levels were measured in the factory at a mean of 82 dBA, with a range of 66-97. No concurrent measurements were taken for the firefighters, but historic comparison values showed a wider range but a similar mean of 76-79 dBA. Although losses during follow-up were negligible, the factory workers had significantly (Korean work environments with continuous noise exposure in the measured range should consider implementation of a hearing conservation program. Further evaluation of hearing loss in workers exposed to irregular or intermittent high noise levels, such as firefighters, is also warranted. Rapid expansion and change in Asian economies has resulted in increasing numbers of workers exposed to high intensity noise. However, in many countries, regulation and control lag behind Japan, Australia and New Zealand and nations in Western Europe and North America. A recent analysis of adult hearing loss  concludeIn Korea, work-related noise induced hearing loss (NIHL) is defined as hearing levels above 30 dB for the average 0.5, 1 and 2 kHz and 50 dB at 4 kHz , constitDespite the magnitude of the problem little research has been published in the international literature regarding how best to control this problem in the local environment . One aspAs part of government mandated surveillance in South Korea, one of the authors (IS Chung) had the opportunity to collect and study hearing surveillance data collected in various work environments over the course of 4 years. Although the surveillance was designed for control purposes and not research per se, we present our findings to contribute further knowledge about noise induced hearing loss (NIHL) in this region and to provide some new empirical data on the effects on hearing loss by noise exposure pattern.Surveillance, including audiograms and a questionnaire, was conducted in a farm machine factory as a continuous regular noise exposure group and among firefighters as an example of an intermittent, irregular noise exposure group for 4 years. Data from 81 male farm machine factory workers and 371 male firefighters who completed a routine annual health exam for 4 years and had no history of ear-related illness were chosen for the final analysis. Although change during the study period was not the focus of the study, data from subjects who had not completed four consecutive annual health exams were excluded to assure a stable group of workers for the study and to compensate for any year to year variation in testing conditions (see below). The medical history questionnaire, "Checkup List for Regular Health Examination,"  attached to individuals. The number of samples depended on the total number of workers at the time data were collected, with a minimum of one sample for every 5 workers each year. Measurements were taken on those who worked closest to noise sources to provide a "worst case" profile. Data were gathered from 31, 31, 32 and 28 workers at the same department of the factory during the 4 years of the study period. No comparable samples were obtained from the firefighters; instead we relied on historic published data on exposure.Pure-tone air conduction hearing thresholds were measured at 0.5, 1, 2, 3, 4 and 6 kHz in both ears every year as a part of an annual routine health examination. The hearing test was administered by an occupational health nurse who had completed a certification course to administer the test. The hearing tests were performed in a sound proof audiometric test booth. The Occupational Health and Safety Agency recommendation to allow at least 14 h of noise-free time prior to hearing test administration was followed. The minimum time of presumed non-exposure was approximately 15 h. For the farm machinery factory workers hearing tests were conducted in the morning prior to their shift. Firefighters generally also took the test in the morning prior to initiating their shift, however in some cases, the test was administered on their day off. The annual health examination also included otoscopy for all workers. Data from workers with abnormal otoscopic findings were excluded from the analysis.t-test was used to test differences between the study groups for quantitative parameters with hearing loss. The χ2 test was used to examine differences between the study groups for demographic data. We measured the difference in hearing thresholds in the two groups using GLM repeat measure adjusted for smoking status (Yes/No), age (continuous) and duration of employment from the original date of hire. We separately analyzed hearing at 1 kHz and the average of hearing thresholds at 2, 3, and 4 kHz. The number of subjects reporting non-occupational exposure to high levels of noise (such as noisy hobbies) was negligible and this covariate was not included in our final analysis.Data were analyzed using SPSS version 16. A two-sample p < 0.0001), more likely to smoke (p < 0.0001) and had a longer duration of employment in their present workplace (p < 0.0001).From the two worker groups we enrolled a total of 1225 workers during a 4-year period (2006-2009). The 452 workers with a completed audiometric examination for four consecutive years were included in the analysis (36.9%). The general characteristics of workers in each group are shown in Table The distribution of noise samples is shown in Table Because of local regulations routine noise level sampling was not performed among the firefighters. Historic data from Korea suggests mean exposures in the range of 76-79 dBA . Previoup < 0.05). Table The two groups differed significantly in their total mean duration of work. The firefighter's mean total work period was 134.01 months compared to the farm machine factory's workers mean of 256.20 months . Age, duration of employment and cohort significantly impacted hearing in the 2-4 kHz frequency range in the simple regression, however in the multiple regression model, duration of employment and smoking were no longer significant  exposure to occupational hazards, such as excessive noise, is likely to increase in tandem unless measures are taken to reduce risk.Our data suggest that the current regulatory threshold of 85 dBA may not be sufficiently conservative. Typical work schedules are 5 days a week for 8 h a day which potentially do not allow adequate recovery time after each period of exposure. Work environments with levels of noise exposure close to 85 dBA should consider implementing a hearing conservation program. Further research is also needed on hearing loss for workers with long term duration of exposure as well as intermittent and irregular exposure to high levels of noise to determine optimal hearing conservation strategies for workers in these environments.The authors declare that they have no competing interests.ISC and MRC were involved in all aspects of the paper including conception and design of the study, acquisition, analysis and interpretation of data, drafting and revising the manuscript and approval of the final version. IMC made substantive intellectual contributions to the interpretation of the data, draft of the manuscript and final version for publication. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2458/12/87/prepubCheckup List for Regular Health Examination.Click here for fileNoise-induced Hearing Loss Work-up Sheet.Click here for file


Under normal hearing conditions, comparisons of the sounds reaching each ear are critical for accurate sound localization. Asymmetric hearing loss should therefore degrade spatial hearing and has become an important experimental tool for probing the plasticity of the auditory system, both during development and adulthood. In clinical populations, hearing loss affecting one ear more than the other is commonly associated with otitis media with effusion, a disorder experienced by approximately 80% of children before the age of two. Asymmetric hearing may also arise in other clinical situations, such as after unilateral cochlear implantation. Here, we consider the role played by spatial cue integration in sound localization under normal acoustical conditions. We then review evidence for adaptive changes in spatial hearing following a developmental hearing loss in one ear, and show that adaptation may be achieved either by learning a new relationship between the altered cues and directions in space or by changing the way different cues are integrated in the brain. We next consider developmental plasticity as a source of vulnerability, describing maladaptive effects of asymmetric hearing loss that persist even when normal hearing is provided. We also examine the extent to which the consequences of asymmetric hearing loss depend upon its timing and duration. Although much of the experimental literature has focused on the effects of a stable unilateral hearing loss, some of the most common hearing impairments experienced by children tend to fluctuate over time. We therefore propose that there is a need to bridge this gap by investigating the effects of recurring hearing loss during development, and outline recent steps in this direction. We conclude by arguing that this work points toward a more nuanced view of developmental plasticity, in which plasticity may be selectively expressed in response to specific sensory contexts, and consider the clinical implications of this. The ability to hear is of critical importance for a wide variety of species. Indeed, in many naturalistic situations, auditory input provides the only source of information about distant events. However, whilst the identity of a sound source is clearly important, its location also plays a critical role in guiding behavior. In noisy and reverberant acoustic environments, spatial hearing can additionally help to separate different sound sources, thereby enabling their subsequent identification Yost, . For theUnlike the visual and somatosensory systems, however, the auditory system does not contain an implicit map of space at the level of the receptor surface. Instead, the receptors that transduce sound are arranged along the cochlea according to their tuning for sound frequency. The brain must therefore actively construct a representation of auditory space by transforming and processing the acoustical inputs provided to each ear. In doing so, the brain takes advantage of the fact that specific aspects of the acoustical input tend to depend on the position of the sound source relative to that of the listener Blauert, . The chaIn many cases, the most effective way to localize sounds will depend on the precise properties of the acoustical environment. While this varies with the nature of the sound sources themselves and the acoustical conditions in which they are encountered, developmental changes in the relative dimensions of the ears and in the neural circuits that process sound will also cause the acoustical environment to change. In order to maintain stable representations of space, the auditory system must therefore adapt to these changes by processing auditory spatial cues dynamically in ways that are appropriate to the prevailing sensory conditions. To understand these adaptive mechanisms, one popular approach that has been used is to manipulate the acoustical input experimentally and study its consequences on the perception and processing of sound. Although the sounds reaching the ears can be altered in a variety of ways, important insights into developmental plasticity have been gained by introducing a hearing loss to one ear  (Loftus et al., In attempting to understand developmental plasticity in the auditory system, numerous studies have investigated the effects of early hearing loss. Although hearing loss can be produced in a number of different ways, these can be broadly categorized as being either sensorineural or conductive in nature, each of which has distinct advantages from an experimental perspective. For example, experimental induction of sensorineural hearing loss, which can be achieved via cochlear ablation (Moore and Kowalchuk, In contrast, conductive hearing loss is typically incomplete, producing only a partial attenuation of acoustic input to the affected ear (Moore et al., Although otitis media with effusion can occur either unilaterally or bilaterally (Hogan et al., From an experimental perspective, a partial hearing loss in one ear can be reversibly induced either by surgical ligation of the ear canal (Silverman and Clopton, Unilateral hearing loss therefore alters the usefulness of auditory spatial cues as well as the precise relationship between specific cue values and spatial location, but leaves any monaural spatial cues available to the intact ear unchanged. The methods used to induce hearing loss also tend to act as low-pass filters, attenuating higher frequencies to a greater extent than lower frequencies (Moore et al., In principle, spatial hearing could adapt to a unilateral hearing loss in two distinct ways. First, in situations where the affected ear retains some acoustical sensitivity, the auditory system could utilize the cues that have been altered by hearing loss. In particular, this would require the brain to acquire new mappings between specific locations and the values of individual spatial cues Figure . In otheThus, far, the clearest evidence for cue remapping has been obtained by studies of partial unilateral hearing loss in the developing barn owl. In particular, sound localization behavior in this species readily adapts to a unilateral hearing loss introduced early in development (Knudsen et al., There are, however, key differences in the way in which barn owls and mammals localize sound, which likely reflect the independent evolution of mechanisms for sound localization in different groups of vertebrates (Grothe et al., Although there is currently very little evidence in mammals for experience–dependent adjustments in binaural cue sensitivity equivalent to those seen in barn owls, this does not necessarily mean that mammals are incapable of adapting in this manner to the altered cues produced by a unilateral hearing loss. In situations where normal hearing cannot be restored, it is therefore important to ask whether it might be possible to devise targeted intervention strategies that promote adaptive adjustments in ILD or ITD sensitivity. The mechanisms of plasticity revealed by research in barn owls therefore illustrate the potential for adaptive changes in the encoding of binaural spatial cues, even if the immediate clinical implications of this work remain unclear.A compensatory adjustment in neural sensitivity represents one viable mechanism for adapting to changes in auditory spatial cues, but this could also be achieved by the auditory system becoming more dependent on other cues that remain unchanged. In the specific case of unilateral hearing loss, this would require the auditory system to ignore the affected binaural spatial cues and instead rely more on the monaural spatial cues available to the intact ear. For individuals with a complete loss of hearing in one ear, this may be the only way in which a recovery in sound localization accuracy can be achieved. Indeed, behavioral evidence in at least some unilaterally deaf humans supports the idea that monaural spectral cues might be used to localize sounds in the horizontal plane (Slattery and Middlebrooks, In such cases, however, it is unclear whether this amounts to cue reweighting, since these individuals do not have access to binaural spatial cues. Nevertheless, in situations where altered binaural cues remain available, it is clear that spatial hearing can adapt to a partial unilateral hearing loss by relying to a greater extent on the spectral cues provided to the intact ear. This has been demonstrated in both ferrets and humans with a unilateral hearing loss experienced either during adulthood (Kacelnik et al., At a neuroanatomical level, developmental studies of unilateral hearing loss in mammals have demonstrated a relative weakening of the pathways that convey input from the affected ear, which include reduced connectivity, reductions in the size and number of neurons as well as changes in dendritic morphology Tollin, . ChangesIn a recent study, we therefore set out to test this cue reweighting hypothesis explicitly Figure  Keating. We founThese studies demonstrate that the developing auditory system possesses the capacity to adapt to a partial unilateral hearing loss in one of two distinct ways. Whereas barn owls can adjust their sensitivity to the altered binaural cues (Keuroghlian and Knudsen, The barn owl, for example, is capable of using fine-structure ITDs over the full range of frequencies to which it is sensitive, a truly remarkable feat that is made possible by phase-locking to much higher sound frequencies than is the case in mammals Köppl, . The acoOn the other hand, barn owls may adapt to the altered binaural cues simply because this is the only viable strategy for adapting to a unilateral hearing loss in this species. In our experiments in ferrets that were monaurally deprived during development, we found that adaptive reweighting of auditory spatial cues is specific to the high sound frequencies (above approximately 16 kHz; Figure Although these different viewpoints provide alternative, and perhaps complementary, explanations for the apparent differences between species, they remain speculative. As such, they serve to highlight important limitations in our understanding of the fundamental mechanisms underlying developmental plasticity. Under certain circumstances, for example, it is possible that both remapping and reweighting strategies could be utilized for adaptation in the same species. This would be consistent with the results of sound localization measurements in human listeners with acquired conductive hearing loss in one ear (Agterberg et al., Factors likely to influence which adaptation strategy is used include the experience of the individual prior to the onset of hearing loss and the extent to which hearing is restored in the affected ear. It is conceivable, for example, that the ability to use binaural spatial cues, whether normal or abnormal, depends on normal binaural hearing during development (Seidl and Grothe, As previously discussed, the capacity of ferrets to adapt to a conductive hearing loss in one ear during postnatal development relies on their greater use of monaural spectral cues provided by the contralateral ear, with equivalent cue reweighting being displayed by auditory cortical neurons in these animals (Keating et al., On the other hand, some measures of spatial processing by IC neurons are immune to the effects of a unilateral hearing loss, despite undergoing changes at higher levels of processing (Popescu and Polley, Whilst it is unclear whether similar principles apply to developing animals, these studies highlight the possibility that cue reweighting may be implemented by interactions between the midbrain and cortex. Consistent with this view, multisensory cue integration in the SC is thought to depend on descending input from “association” cortex, both during adulthood and development (Wallace and Stein, Although developmental plasticity can be beneficial, enabling an individual to adapt to a particular environment, these adaptive changes are often incomplete. For example, ferrets reared with an earplug in one ear localize sounds less well whilst wearing an earplug than controls with normal hearing (Keating et al., Perhaps more damagingly, however, any adaptive changes that do occur can become maladaptive if the environment is subsequently altered. This is particularly relevant to situations where a developmental hearing loss is resolved later in life, either spontaneously or through clinical intervention. In such cases, the auditory system may have altered the way in which spatial cues are processed, thereby compromising its ability to take full advantage of normal hearing when it becomes available.Following a developmental hearing loss in one ear, for example, barn owls are, at least initially, unable to localize sounds correctly when normal hearing is restored (Knudsen et al., Similarly, in mammals reared with a stable hearing loss in one ear, the neural representation of the developmentally occluded ear is typically [though not always (Moore and Irvine, In a recent study, for example, rats were reared with a conductive hearing loss in one ear and binaural interactions were quantified in the ICc and auditory cortex after the hearing loss was reversed (Popescu and Polley, Consistent with this view, humans and guinea pigs with a developmental history of asymmetric hearing loss tend to show persistent deficits in behavioral measures of binaural and spatial hearing even after normal hearing is restored (Clements and Kelly, Nevertheless, whilst long periods of unilateral hearing loss may weaken the neural representation of the deprived ear, this representation does not appear to be eliminated entirely. For example, ferrets reared with an earplug in one ear eventually show normal levels of binaural unmasking, although this can take up to approximately 2 years after the cause of the hearing loss has been removed (Moore et al., One of the key findings to emerge from studies of spatial hearing following unilateral hearing loss is that the timing of hearing loss plays a critical role in mediating its effects. Early work in the barn owl, for example, emphasized the notion of sensitive or critical periods (Knudsen et al., A number of studies in which individuals have been exposed to altered auditory or visual experience have, however, demonstrated that spatial hearing remains plastic in adulthood [reviewed by Irvine and Wright , KeuroghAdditional work, however, suggests that adult plasticity is possible even in the absence of behavioral training, with changes in frequency tuning induced by passive exposure to specific acoustic environments (Noreña et al., On the other hand, the effects of attention and reward are not limited to adults, with developing circuits relevant to vocalization showing a similar susceptibility to these influences (Doupe and Kuhl, Although the auditory system can adapt to a unilateral hearing loss both during development and in adulthood, the consequences of this form of auditory deprivation have been shown to vary depending on the point in development at which hearing loss first occurs. Earlier developmental onsets result in a greater weakening of the neurophysiological (Clopton and Silverman, If spatial hearing were particularly vulnerable to hearing loss early in development, we might expect clinical intervention to be more successful early in life. Consistent with this view, one recent study used hearing aids to restore balanced hearing to children who had previously been diagnosed with a sensorineural hearing loss in one ear (Johnstone et al., Recipients of cochlear implants who are congenitally deaf also provide a unique opportunity to study this question. In recent work, for example, sequential implantation of the two ears was found to impair the ability to make use of the second implant if it was implanted much later in life than the first (Graham et al., More recent work, however, points toward a more complex situation, in which different aspects of binaural sensitivity are vulnerable to hearing loss at different stages of development (Polley et al., Although the timing and duration of hearing loss are likely to have a significant impact on spatial hearing, the temporal pattern of the impairment may also be a critical factor. In this respect, most research in this area has been restricted to studying a particular type of auditory deprivation, namely a single episode of unilateral hearing loss that remains stable over time (Clopton and Silverman, On the one hand, we might expect that the effects of hearing loss would be reduced by periods of normal hearing. Studies of the visual system, for example, have shown that the negative effects of occluding one eye during development can be at least partially (Mitchell et al., Alternatively, intermittent periods of hearing loss might be damaging, producing an unstable acoustical environment in which the auditory system is unable to develop properly. In one early study, for example, barn owls were reared with unilateral earplugs that alternated between the two ears every second day (Knudsen and Knudsen, We addressed this issue in our recent study in which ferrets were reared with a unilateral hearing loss by providing brief intermittent periods of normal hearing throughout development (Keating et al., This is consistent with clinical observations in humans, which show that the negative effects of a recurring hearing loss are reduced as the cumulative amount of abnormal hearing is decreased (Hogan and Moore, Another important issue, however, concerns the amount of normal sensory experience that is required to avoid the negative effects of hearing loss. In humans, deficits in spatial hearing are observed if the proportion of abnormal hearing exceeds 50% (Hogan and Moore, Although studies of recurring hearing loss are directly relevant to otitis media with effusion and its treatment (Hogan et al., Our finding that juvenile ferrets can adapt to a recurring hearing loss in one ear by relying more on the monaural spectral cues provided to the intact ear when the hearing loss is present, whilst maintaining sensitivity to binaural cues under normal hearing conditions, suggests that the developing auditory system can process spatial cues in different ways depending on the specific environmental context in which they are experienced (Keating et al., By showing that developmental plasticity enables context-dependent cue integration, this result ties together two distinct lines of research on cue integration. On the one hand, developmental studies have demonstrated that the emergence of cue integration depends on prior sensory experience (Wallace and Stein, Similarly, in the auditory system, there is accumulating neurophysiological evidence for various forms of context-dependent processing. Cortical activity, for example, shows rapid changes when individuals are required to perform specific tasks, with the nature of these changes being determined by the specific task requirements (Fritz et al., In the specific case of spatial hearing, a key goal for future research will be to characterize the neural circuitry that enables developmental plasticity to be selectively expressed in specific contexts. One possibility is that the brain maintains neural circuits that are appropriate for different sensory contexts but functionally silences circuits that are not appropriate for the prevailing sensory conditions. Consistent with this view, studies in barn owls have shown that prism rearing results in the emergence of novel connections between the ICX and the optic tectum, which provide an anatomical basis for adaptive shifts in ITD tuning that realign the tectal maps of auditory and visual space. These abnormal connections persist following the removal of the prisms and coexist with connections that are appropriate to normal sensory experience, which likely accounts for the capacity of the owls to readapt in later life to the same audiovisual mismatch encountered during development (Linkenhoker and Knudsen, Interestingly, only one set of connections between the ICX and optic tectum appears to be functionally expressed at any given time, with GABA-mediated inhibition implicated in the selection and stabilization of a particular set of connections (Zheng and Knudsen, In this way, prior experience can produce changes in neural circuitry that appear to be functionally silenced unless the brain is exposed to specific sensory conditions. Although sensory systems may require relatively long periods of time to switch on functionally silenced circuits, it is equally possible that the brain might learn to rapidly transition between using different circuits. This is likely to be particularly true in situations, such as a recurring hearing loss in one ear, where the auditory system has plenty of experience in switching between different acoustical conditions (Keating et al., B receptor-mediated adaptation in the population code for ITDs found in the MSO (Stange et al., However, whilst a recurring hearing loss can produce dramatic changes in auditory input, acoustical conditions can also vary, albeit to a lesser extent, in naturalistic environments. Context-dependent updating of spatial processing is therefore likely to be a general feature of the auditory system, even in individuals without a history of hearing loss. Consistent with this view, two recent studies have shown that the mature auditory system can undergo rapid changes in binaural spatial processing in response to prior acoustical stimulation. In one of these studies, shifts in ILD sensitivity were observed in the ICc as a function of prior stimulus statistics (Dahmen et al., Studies of asymmetric hearing loss have shown that the mechanisms underlying spatial hearing are remarkably plastic during development, with behavioral adaptation in response to altered sensory inputs reported in different species. The underlying basis for adaptation to asymmetric hearing loss appears, however, to vary across species. Thus, barn owls can learn with experience to use altered binaural spatial cues, whereas mammals appear to become more dependent on cues that remain intact and less on those that change in value as a result of the hearing loss. Further research is therefore needed to unravel the reasons for this difference. In addition, whilst the neural basis for behavioral plasticity has been well characterized in barn owls, corresponding studies in mammals are still at a comparatively early stage, highlighting the need for further work in this area.Although this capacity for change enables the auditory system to adapt to abnormal acoustical inputs, it also represents a major source of developmental vulnerability. In many cases, prolonged periods of hearing loss may lead to amblyaudia, a condition in which the auditory system is unable to fully exploit acoustical input provided to the affected ear if normal hearing is subsequently restored. To the extent that binaural spatial hearing is important for speech comprehension in noisy, naturalistic environments, this may have secondary effects on linguistic, cognitive, social and educational development. It is therefore important to identify individuals who are particularly at risk and identify appropriate strategies for clinical intervention.In this respect, a key finding to emerge from studies of asymmetric hearing loss is that spatial hearing may be particularly labile early in development. The timing and duration of hearing loss, as well as any necessary clinical intervention, are therefore of considerable importance. Although the stability of hearing loss is likely to play a similarly important role in determining whether intervention is necessary, as well as guiding how intervention might be successfully achieved, this issue has received much less attention in the experimental literature. Recent work, however, suggests that brief intermittent periods of normal hearing may play a protective role, reducing the longer term effects on auditory function when normal inputs become available. In this way, recurring forms of hearing loss may be less damaging than more stable deficits in hearing. Consequently, for individuals who experience a stable hearing loss in one ear, the provision of even relatively brief, intermittent periods of balanced hearing may help to protect against amblyaudia.Investigation of how the auditory system responds to recurring hearing loss is likely to provide additional insight into a fundamental aspect of neural processing, namely the mechanisms that enable sensory inputs to be processed differently depending on the context in which they occur. In this respect, the context-dependent cue integration revealed by these studies may represent one of the mechanisms through which the auditory system maintains stable and efficient representations of auditory space in different acoustical environments.To the extent that auditory processing and perception are influenced by sensory context, research in this field may also have important implications for rehabilitation strategies following hearing loss. It has been suggested, for example, that cochlear implants could make use of signal processing strategies that are optimized for specific acoustical contexts, and switch between those strategies depending on the prevailing acoustical conditions (Hu and Loizou, The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Stellate silencing is achieved by the piRNA pathway, but many features still remain unknown. Here we outline the important role of the crystal-Stellate modifiers. These have shed light on the piRNA pathways that defend genome integrity against transposons and other repetitive elements in the gonads. In particular, we illustrate the finding that HSP90 participates in the molecular pathways of piRNA production. This observation has relevance for the mechanisms underlying the evolutionary canalization process.The Stellate-made crystals formation in spermatocytes is the phenotypic manifestation of a disrupted  They also described the morphological differences between needle-shaped and star-shaped crystals [The history of the Y chromosome. They showed that the hll region contains the genetic determinants for normal chromosome behavior during male meiosis and for the suppression of Stellate-made crystals formation in spermatocytes [Suppressor of Stellate [Su(Ste)] locus, also referred to as crystal (cry) . The crystal-specific piRNA, reported to be the most abundant one in testes, is only antisense [The majority of these piRNAs do not show the ping-pong signature. There are only 3 pairs exhibiting the A at the 10th position of the “sense” piRNA, and these “sense” piRNAs show 2 or 3 mismatches with ntisense , Figure crystal and Stellate sequences. crystal- and Stellate-specific piRNAs cooperate in some way to silence the Stellate euchromatic and heterochromatic sequences that produce the Stellate protein (“active elements”) [For all the reasons reported above, we hypothesize that different though interconnected pathways exist to silence ements”) , 20. TheAT-chX, on the X chromosome [AT-chX piRNAs. These remarks confirm that the ping pong is not the only piRNA pathways operating in the silencing of these repetitive sequences in testes [In support of these considerations, we refer to the previous data on the silencing of another class of repetitive sequences in testes. In fact, a second large class of piRNAs associated with Aubergine in the testes is derived from a short repeated region, termed romosome . These pn testes .aubergine, ago3, spindle E, armitage, zucchini, and squash, lead to the formation of the Stellate-made crystals in spermatocytes [Mutations in piRNA-pathway genes, such as atocytes , 21–24.spindle-E encodes a member of the DExH family of ATPases with a Tudor domain. Mutations in this gene are known to impair Stellate and transposon silencing in the Drosophila germline. In ovaries spindle-E acts specifically in germ cells and in the ping-pong cycle [ng cycle , 22, 25.Armitage encodes a homolog of the Arabidopsis SDE3, an RNA helicase that is involved in RNAi. Mutations in armitage affect translational repression and localization of oskar mRNA, block RNAi in Drosophila oocytes, and impair Stellate silencing in testes [armitage acts in the primary piRNA pathway [ zucchini was identified in a screen for female sterile mutations, and causes dorsoventral patterning defects. This gene encodes a nuclease. Mutations in zucchini lead to formation of Stellate crystals [ zucchini mutations specifically decrease the piRNA levels in somatic ovarian cells [n testes , 26. In  pathway , 27, 28.crystals . In ovaran cells .crystal-Stellate interaction that have been related to the piRNA pathways in gonads. Mutants of genes implicated either in the primary piRNA pathway, excepting piwi, or in the secondary ping-pong amplification pathway show crystals in their spermatocytes.In Drosophila testes. Because Stellate-made crystals are symptomatic of a disrupted crystal-Stellate interaction, they allow the identification of new genetic components of the piRNAs pathway. An emblematic example is the discovery that the hsp83 gene participates in piRNA.After all, we are convinced that the molecular mechanisms, underlying the piRNA pathways, are not completely understood and that there are more players to be discovered in both the somatic and germline-specific piRNA pathways. The genetic characterization of known and still unknown components, combined with the deep sequencing strategy of the piRNAs bound to specific Piwi proteins, will help us in understanding the piRNAs production and function in the  hsp83 gene encodes HSP90 protein, a molecular chaperone involved in several cellular processes and developmental pathways [scratchhsp83  homozygous mutant males exhibit Stellate-made crystalline aggregates, suggesting a role for this protein in the piRNA-mediated mechanisms. We also demonstrated that scratchhsp83  affects the biogenesis of the crystal/Stellate-specific piRNAs and transposon piRNAs in testes. We went on to demonstrate that the effect of HSP90 in morphological variations is due, at least in part, to activation of transposons causing de novo mutations [hsp83 mutant flies showing morphological abnormalities, we selected one exhibiting a Scutoid-like phenotype and demonstrated that this phenotype is caused by the insertion of an I element-like transposon in the noc gene of this fly.Thepathways –33. We hutations . Among tThe role of HSP90 in piRNAs-mediated silencing is in addition to the “buffering” role on the genetic cryptic variation initially put forth by Rutherford and Lindquist  as the mCanalization is the resistance of an organism to phenotypic variation during development, in the presence of genetic and environmental changes. This “phenotype robustness” is due to buffering mechanisms. Severe perturbations, which reduce buffering, produce heritable phenotypic variants that can be canalized by a genetic assimilation process . An inteFurther mechanisms could be involved in increasing the phenotypic variations underlying evolution. One of these could be related to HSP90-mediated epigenetic chromatin modifications , 37.Precise localization of specific piRNAs on the Stellate (X15899) and crystal (Z11734) sequences. In order to visualize the region of the Stellate and crystal sequences that share homology with the most abundant piRNAs related to them , we precisely localized some of these piRNAs on the sequences.We selected two emblematic sequences for Stellate (X15899) and crystal (Z11734). We also reported their orientation and the Argonaute proteins which the reported piRNAs are bound to.Click here for additional data file.Click here for additional data file.


The high incidence of age-related hearing loss demands accessible, low cost hearing screenings for prevention and hearing health promotion. This study assessed performance of self report (SR) against audiometry, and prevalence of hearing difficulty when screening hearing in middle-aged and younger adults, including smokers and nonsmokers.Prospective participants (N = 219) completed a questionnaire providing biographical, health, and smoking information. Their Yes/No responses about hearing or communication difficulty provided data for self-reported hearing loss. Eligible (N = 170) participants received a hearing test including immittance, pure-tone, and speech audiometry. The binaural pure-tone average (PTA) hearing threshold was determined; PTA decibel (dB) level indicated degree  of hearing loss. All hearing screening data were coded and initially analyzed in an Access database. Statistical analyses based on conditional probability included measures of prevalence, sensitivity, specificity, and predictive value of the SR versus audiometric measures. Participants provided a urine sample for biochemical analysis to confirm smoker/nonsmoker status.Among all participants (N = 170), overall prevalence of self-reported hearing difficulty (15.9%) was in excellent agreement with measured, mild hearing loss (16.5%). However, factoring in age and smoking revealed that SR was incongruent with audiometry because hearing loss was overestimated by smokers and younger participants and underestimated by middle-aged individuals. The SR question yielded high specificity (80-90%) overall. Specificity was highest in nonsmokers (89-94%) and younger (90-91%) individuals with lower performance in smokers and middle-aged participants. SR sensitivity was high (86-100%) only when the hearing impairment cutoff was > 40 dB (moderate loss) and > 60 dB (severe loss). Sensitivity was highest in smokers (100%), supporting SR for screenings. High negative and low positive predictive value (PPV) occurred in smokers, younger, and middle-aged persons. This study reports new sensitivity and specificity data on self-reported hearing difficulty in smokers (N = 98), younger (N = 80), and middle-aged (N = 90) adults, indicating efficacy of SR as an adult hearing screening measure.SR was effective as few normal-hearing persons were labeled “hearing-impaired”. However, audiometry should supplement SR to optimize detection of mild hearing loss for at-risk adults. Results may guide community health initiatives for hearing screenings, prevention, and health promotion.Aging; Smoking; Self Report; Health Promotion; Hearing Screening In considering the effects of a health condition, the World Health Organization (WHO) promotes a holistic model so that disability is viewed in terms of activity limitations and participation restriction for the affected individual. For example, a chronic disability like hearing loss shows effects including a loss of independence and a poorer quality of life in aging adults . Degree Hearing screening protocols might be impacted by health disparities. The elimination of health disparities among disabled persons is prioritized in Healthy People 2010 . There aHearing Handicap Inventory for the Elderly-Screening” (HHIE) for self reported hearing loss indicated higher sensitivity and lower specificity among adults aged 48-64 years (baby boomers) compared to older adults aged 65-92 years [Adult hearing screening protocols in the U.S. are not easily accessible, universal, or available at low cost . The cha92 years . The hig92 years  but it w92 years . However92 years . There a92 years .The current study, therefore evaluated adult hearing screening techniques by examining sensitivity and specificity of a single question SR compared with the gold standard, pure-tone audiometry and an alternate gold standard, word recognition score (WRS) in a sample of healthy, middle-aged and younger adults, including smokers and nonsmokers. It was hypothesized that SR sensitivity and specificity would be high in the group of middle-aged adults , 25, SR Data collection was completed at two universities, one Midwest and one in the Southeast following Institutional Review Board approval of study materials and test protocols for human subjects. Participant recruitment targeted healthy adults in two age ranges: 19-30 years (young) and 45 years or older (middle-aged); the 30-44 year range was not included for this study. Recruiting occurred via flyers posted in the community and by word of mouth. Over 300 inquiries were received from prospective participants. A total of 219 individuals completed a questionnaire providing biographical, health, and smoking information. Of these, 49 (22%) were not eligible due to age or health reasons. The remaining 170 participants (78%) who reported good overall health with no alcohol or drug dependency, mental illness, or neurological disease were selected for the study.Of 170 participants, 61 were male. Mean age of the younger group (N = 80) was 24 years (S = 3.9). Two-thirds of the middle-aged group (N = 90) were baby boomers with a mean age of 62 years (S = 9.3). Participants were initially categorized as nonsmoker (N = 98) or smoker (N = 72) based on their responses to items on the questionnaire with later confirmation by biochemical urine testing. Among nonsmokers, 77 reported having never smoked and 21 were past smokers who had quit at least 3 years before. Among smokers, 60% reported moderate-to-heavy smoking (11-20 cigarettes per day), and 15% smokers reported heavy smoking (> 21 cigarettes per day), defined by benchmark guidelines from the Fagerstrom Test for Nicotine Dependence .Do you have any hearing or communication difficulties?” had a Yes/No response option, and participants responses provided the data for self reported hearing loss. Participants attended one 30-40 minute hearing testing session in a research laboratory. A certified audiologist or audiology graduate assistant visualized the external ear canals and tympanic membranes with an otoscope, and then measured each participant’s hearing with pure tone air-conduction, immittance, and speech audiometry. Pure tone testing was conducted in a sound treated booth using a standard two-channel audiometer. Hearing thresholds were measured in each ear for frequencies: 250, 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hertz (Hz). Participants were instructed to listen to sounds of different pitch through insert earphones placed in each ear, and indicate when stimuli were heard by pressing a button, hand raising, or saying "yes". Hearing thresholds, defined as the softest level at which a signal is heard 50% of the time, were determined by standard clinical procedures [Each participants hearing was estimated by screening with a binary classification test (single question) that was included on the questionnaire. Specifically “ocedures . Speech oC. Urine samples were analyzed with high performance gas chromatography at an independent laboratory for presence/absence of nicotine and cotinine. Biochemical laboratory reports were compared to each participants reported smoking behavior with 100% agreement. This confirmation of participant categorization as a smoker or nonsmoker was the sole purpose of the urine sample.Participants provided a urine sample in a standard collection cup while at the research facility. Each sample was dated, labeled, and stored in a refrigerator at 4Participants’ responses on the questionnaire were coded and entered into an Access database program . Self reFor the statistical analyses, participants were grouped as middle-aged (N = 90), younger (N = 80), smokers (N = 72), nonsmokers (N = 98), and All (N = 170). Hearing screening techniques were evaluated with statistical measures of prevalence, sensitivity, specificity, and predictive value, determined within the framework of conditional probability . PrevaleThe primary purpose of this study was to evaluate an adult hearing screening technique, SR considering age and smoking behavior. Prevalence of hearing loss was estimated by SR and measured by audiometry . For theScreening characteristics including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of SR compared with audiometric techniques  are shown in Overall, sensitivity was low (33-58%) in two comparisons and high (86-100%) only when hearing loss was moderate or severe. Sensitivity was highest (56-100%) in smokers than all other participants when hearing loss was mild, moderate, or based on WRS. Sensitivity was excellent (100%) and equal among participants when hearing loss was severe.In general, PPV scores were low across all comparisons of SR to PTA and WRS. However, PPV was modestly high (68%) for middle-aged participants when SR hearing difficulty was compared to mild hearing impairment. NPV was excellent (89-100%) across all comparisons of SR to PTA and WRS, particularly in younger participants. In middle-aged participants, however, NPV was much lower (78%) when SR was compared to PTA > 25dB.The current prevalence (31%) of measured hearing loss  in middle-aged participants is an excellent match to earlier reports . In contAn interesting new finding in this study regarding the difference between measured and estimated prevalence, indicated that younger participants and smokers overestimated self reported hearing loss. No other known studies have reported how younger individuals or smokers perform on SR versus measured hearing screening tests. This self reported hearing loss that was not verified by physiological hearing changes (PTA > 25 dB) might indicate early signs of functional hearing difficulties. For example, noise exposure in younger persons might lead to temporary threshold shift and similarly, smokers might be experiencing poorer speech understanding in noisy or other challenging listening situations , 10, 11.Do you have any trouble hearing” [Do you feel you have a hearing loss” [The difference between measured and estimated prevalence (M - E) revealed that middle-aged individuals in this study underestimated (10%) hearing loss by SR. This result was unexpected. It was anticipated that baby boomers would view even slight hearing difficulties more importantly than elderly individuals . Althoughearing”  or “Do yng loss”  imply diDo you have any hearing or communication difficulties?” in younger and middle-aged adults, including smokers and nonsmokers. The overall findings indicated high specificity and lower sensitivity of the SR measure compared with audiometry (PTA). This is in keeping with the inverse relationship of the two characteristics. It might be addressed in terms of the relative importance of sensitivity and specificity for prevalence of hearing loss and any consequences of errors in the screening process.Discussion of screening characteristics for the comparison of SR to WRS is excluded because it revealed the poorest/lowest sensitivity and specificity indicating its lack of suitability as an alternate gold standard in hearing screening tests. The current study evaluated sensitivity, specificity, NPV, and PPV of self reported hearing difficulty from a single question “Middle-aged adults in this study revealed higher specificity than sensitivity of the SR measure which is similar to previous findings in older individuals , 30. MorNew findings in this study revealed the highest specificity of SR occurred in nonsmokers for mild and moderate hearing losses. One possible reason for this result might be that nonsmokers were pathology free as they reported being healthy, without any effects of nicotine/smoking. Similarly, younger participants followed by nonsmokers had the highest specificity for severe hearing loss and speech scores. This might be due to younger participants having good hearing and health, and being free of aging effects. In support of this explanation, current smokers and middle-aged individuals revealed the lowest specificity in two conditions as discussed earlier.Overall high specificity in this study suggests that the SR question would be effective in ensuring that fewer people with normal hearing are labeled as hearing impaired in the screening process. This is particularly true for nonsmokers and younger individuals as they had the highest specificity. However, clinical caseloads that include smokers and middle-aged individuals should expect a slightly lower specificity of the SR screening question.Overall, high sensitivity of the SR question is desirable if the reason for screening adults is to provide intervention. However, the current results do support the benefits associated with quickly and easily screening adults at risk for hearing impairment, such as smokers, and baby boomers who are expected to have been exposed to excessive noise.In middle-aged participants, sensitivity of the SR question compared with audiometry (mild hearing loss) was lower (46%) than past reports (51-78%) , 23, 30.Higher sensitivity of the SR question among smokers compared to other participants suggests that SR has a higher probability of correctly identifying hearing loss in smokers. Therefore, clinical use of SR is encouraged for hearing screening in adult smokers. However, the need for supplemental audiometry is evident as discussed above to detect mild impairment in smokers.The low PPV scores overall are not surprising given the low sensitivity scores. In contrast, NPV scores are excellent across PTA and WRS for all participants. This current result of high NPV and low PPV was reported previously in older individuals . In thisSR screening tools should be considered appropriate for adults, including smokers, baby boomers, and younger individuals.Audiometric screening should supplement SR screening to facilitate intervention for adults with mild hearing loss.Adults who fail hearing screenings should be referred to an audiologist for diagnostic testing and management of hearing loss.Adults with mild hearing losses, especially those not interested in hearing aids, should receive counseling about hearing protection, assistive listening devices, health protection supplements, and avoiding excessive noise and smoking.The present study revealed excellent sensitivity and specificity of the SR question with a 40 dB (moderate) hearing impairment cutoff. However, sensitivity was sacrificed somewhat with a 25 dB (mild loss) cutoff. These results have implications for nurses and other community health personnel developing adult hearing screening protocols:This study did not seek information about noise exposure history from participants which might be useful to correlate with reported and measured prevalence of hearing loss. Also, data management resulted in the group of smokers including both younger and middle-aged adults. It is possible that baby boomers in the smokers group were potentially impacted by a combination of noise exposure, smoking, and aging effects. Future research might aim to create more homogenous participant groups.Whereas past studies evaluating self reported and measured hearing loss have focused on older adults, this study included other persons at risk for hearing impairment, including smokers, as well as younger adults and baby boomers possibly exposed to excessive noise. Information from this study with specific suggestions for using SR and audiometry as discussed above would assist public health professionals by guiding screening protocols. In addition, this information may be used to educate physicians, medical residents, and nurses through graduate or continuing education programs. Such clinical and educational efforts would promote hearing health, and support U.S. government mandated Healthy People 2020 initiatives.


Numerous clinical studies have reported that ingestion of chocolate has reduced risk of metabolic syndrome. In order to elucidate the mechanism, we evaluated the influence of flavan-3-ols derived from cocoa powder on energy metabolism in mice using an indirect calorimetric method.The mice were divided into two groups, and administered either distilled water or 50 mg/kg of flavan-3-ol fraction for 2 weeks. At the end of the experimental period, animals were sacrificed after blood pressure and the mean respiratory exchange ratio (RER) over 24 hours were measured.The mean respiratory exchange ratio (RER) over 24 hours was reduced significantly in the flavan-3-ols group. The mean blood pressure was significantly decreased in flavan-3-ols treatment group compared with control group. The protein level of carnitine palmitoyltransferase 2 (CPT2) was increased significantly by flavan-3-ols in skeletal muscle, but not in liver. Uncoupling protein (UCP) 1 was increased significantly in brown adipose tissue by flavan-3-ols. The mitochondria copy number in gastrocnemius and soleus muscles and brown adipose tissue were increased significantly by administration of flavan-3-ol fraction.These results suggest that flavan-3-ols enhances lipolysis and promotes mitochondrial biogenesis. We conclude that improvement of metabolic syndrome risk factors following ingestion of chocolate may be induced, in part, by the mitochondrial biogenesis-promoting effect of flavan-3-ols. Flavan-3-ols, a group of polyphenolic substances, are distributed in a number of plant foods such as cocoa beans, red wine, and apples. Of these foods, chocolate is known to be rich in flavan-3-ols, including the flavan 3-ol monomers, (+)-catechin and (−)-epicatechin, and oligomers, B-type procyanidins that are linked by C4-C8 bonds -3. RecenOn the other hand, it has been reported that the absorption rate of flavan-3-ol monomers was only about 10 - 20%, with these compounds present in blood mainly as metabolites such as conjugated forms with glucuronide and/or sulfate. In contrast, unchanged forms were nearly absent after ingestion of flavan-3-ols . Flavan In order to elucidate this mechanism, we evaluated the effect of repeated supplementation of flavan-3-ols on energy metabolism using an indirect calorimetric method. We also compared the changes of uncoupling protein, lipid metabolizing enzymes and mitochondria copy number in several tissues between with or without treatment of flavan-3-ols.3CN and 0.1% trifuloroacetic acid in H2O using Deverosil ODS HG-5 column  and detected at 280 nm.The flavan 3-ol fraction was provided by Meiji Co., Ltd . The flavan- 3-ol fraction was prepared from cocoa powder by the method described in a previous report . BrieflyThe study was approved by the Animal Care and Use Committee of Shibaura Institute of Technology. All the animals received humane care under the guidelines of this institution.Seven weeks old male C57BL/J mice were obtained from Clea Japan . The mice were kept in a room at a regulated temperature of 23–25°C and controlled lighting (12-h light and dark cycles). The basal diet was MF obtained from the Oriental Yeast, Co. Ltd., Tokyo, Japan.2 and VCO2 were determined by indirect calorimetry using a small animal metabolic measurement system . The system monitored VO2 and VCO2 at 3-min intervals and calculated the respiratory exchange ratio (RER). RER was calculated by following formula; RER = VCO2/VO2. The measurements of VO2 and VCO2 were converted to resting energy expenditure (REE)  using the Weir equation by following formula; REE = (3.941VO2 + 1.11VCO2)*1.44*60(min)*24(h). To measure spontaneous motoractivity while sedentary, the mouse was placed individually in a chamber equipped with an infrared-ray passive sensor system . Measurements were performed during dark (from 19:00 to 7:00) and light (from 7:00 to 16:30) periods under fasting conditions. The blood pressure of each animal was measured by a tail-cuff method  before and at the end of the supplementation period. After all the measurements had been completed, the mouse was anesthetized and its blood sample was collected from the abdominal vein using heparinized syringes. Tissues samples were then collected by dissection and snap frozen in liquid nitrogen and stored at −80°C until analysis.Twelve animals were fed the basal diet for 4 days and then allocated to two groups. Mice in the control group received oral intake of distilled water, while animals in the flavan-3-ols group were administrated flavan-3-ols  in distilled water for 2 weeks. At the end of this supplementation period, each mouse was placed into an open-circuit metabolic chamber for a 24-hour fasting period, and then VOPlasma glucose and free fatty acid levels were determined by commercially available kits .Each tissue was homogenized in micro tubes with lysis buffer  containing protease inhibitor (SIGMA-Aldrich Japan) and 0.2% SDS. The protein concentration was measured by the Bradford method. A 50 μg aliquot of protein was separated by SDS-PAGE using 4-12% Bis-Tris gel and then transferred onto polyvinylidene difluoride membranes . The membranes were blocked with membrane blocking reagent  for 1 hour, and then incubated for 2 hours with rabbit polyclonal primary antibodies against either UCP1 , UCP2 , UCP3 , CPT-2 , MCAD  or α-tubulin . After the primary antibody reaction, the membranes were incubated for 1 hour with the appropriate horseradish peroxidase-conjugated secondary antibody (1:100000). Immunoreactivity was detected by chemiluminescence using the ECL select™ Western Blotting Reagent . Fluorescence band images were analyzed using Just TLC  analysis software. Each value was normalized relative to α-tubulin.T), which represents the PCR cycle count when fluorescence measurement reaches a target value. mtDNA copy number was expressed relative to nuclear DNA following amplification of the mitochondrial gene region .To measure mitochondrial DNA (mtDNA) copy number, total DNA was isolated from each organ using the QIAamp® DNA mini kit , and 50 ng of total DNA used for real-time PCR. PCR was performed using a Step One real-time PCR system . The primer and probe sets used were TaqMan® Gene Expression Assay . The buffer used in the system was TaqMan® Gene Expression Master Mix (Applied Biosystems). The PCR cycling conditions were 50°C for 2 min, 95°C for 10 min, followed by 40 cycles of 95°C for 15 s, and 60°C for 1 min. Data analysis was based on measurement of the cycle threshold  in brown adipose tissue was elevated significantly in the flavan-3-ols group compared with the control group , that are expressed at high levels in brown adiposities [We observed an elevation in mitochondria copy number in skeletal muscle following supplementation of flavan-3-ols. A similar increase in mitochondrial biogenesis in skeletal muscle was also reported in patients with type 2 diabetes or heart failure following ingestion of cocoa . Accordiposities . In the This study suggested repeated ingestion of flavan-3-ols derived from cocoa was enhanced lipolysis and promoted mitochondrial biogenesis. These effects may contribute to the improvement in metabolic syndrome risk factors demonstrated in several meta-analyses.2 uptake by lungs; VCO2: Rate of CO2 output or elimination by the lungs; REE: Resting energy expenditure; CPT2: Carnitine palmitoyltransferase; MCAD: Medium-chain acyl-CoA dehydrogenase; UCP: Uncoupling protein; NE: Norepinephrine; PGC-1α: Peroxisome proliferator-activated receptor γ coactivator α; PPARs: Peroxisome proliferator-activated receptors; ERRs: Estrogen-related receptors; MEF2: Myocyte enhancer factor 2; FoxO1: Forkhead box class-O; ATF2: Activating transcription factor 2; CREB: cAMP response element-binding protein.RER: Respiratory exchange ratio; VO2: Rate of OThe authors declare that there are no competing of interest.NW and KI carried out all the experiments. NW performed the data analysis and created the figures. NO and MS contributed to the design of the study. NO designed and wrote the manuscript and contributed to the final version. All authors contributed to and have approved the final manuscript.