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Results 251 - 300 of 646
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McBride D I - - 2001
OBJECTIVES: To investigate the relation between different types of exposure to noise and a classic sign of noise induced hearing loss (NIHL), the audiometric notch. METHODS: The study sample had exposure to both continuous and impulse noise and was drawn from a population of electrical transmission workers. Audiograms, taken as ...
Hamernik R P - - 2000
Changes in cubic distortion product otoacoustic emissions (DeltaDPOAEs), evoked potential threshold shifts (TSs) and outer hair cell (OHC) losses were measured in a population of 95 noise-exposed chinchillas. Each animal was exposed to one of 23 different noises in an asymptotic threshold shift (ATS) producing paradigm or an interrupted noise ...
Selvadurai DK - - 2000
INTRODUCTION: Pharmacological protection of cochlear function is one of the most exciting goals of inner ear medicine. The selective glutamate antagonist MK 801 may be neuro-protective to the cochlea.1 This study aims to investigate whether round window administration of MK 801 protects cochlear function against a combination of noise and ...
Fechter L D - - 2000
Hearing loss is the most common occupational disease in the United States, with noise serving as the presumed causative agent in most instances. This investigation characterizes the exposure conditions that facilitate the potentiation of noise-induced hearing loss (NIHL) by carbon monoxide (CO). Auditory function was compared in rats exposed 4 ...
Monahan J L - - 2000
The present research examined the possibility that repeated exposure may simultaneously produce specific and diffuse effects. In Study 1, participants were presented with 5-ms exposures of 25 stimuli each shown once (single-exposure condition) or with five repetitions of 5 stimuli (repeated-exposure condition). Participants in the repeated-exposure condition subsequently rated their ...
Kopke R D - - 2000
The effects of a combination of two antioxidant compounds were studied in a chinchilla model of noise-induced hearing loss. After obtaining baseline hearing thresholds using inferior colliculus evoked potentials, chinchillas were exposed for 6 h to octave band noise centered at 4 kHz (105 dB SPL). Post-noise thresholds were obtained ...
Pratt H - - 2000
OBJECTIVES: Short latency visual evoked potentials (SVEP), in response to high-intensity flashes from light emitting diodes (LED), were used to detect subclinical effects along the visual pathway in four groups of subjects with different levels of exposure to gasoline, all within legally acceptable limits. METHODS: Potentials and exposure levels were ...
Liu Y G - - 2000
Objective. To explore prior noise exposures or sound conditioning as a moderator of hearing loss produced by traumatic exposure to low or middle-frequency noise. Method. Two experimental groups of guinea-pigs were conditioned using a 0.5 kHz octave band noise (OBN) at 85 dB, 6 h/d for 4 d. The subjects ...
Yoshida N - - 2000
The phenomenon of conditioning-related protection, whereby prior exposure to moderate-level, non-traumatic, sound protects the ear from subsequent traumatic exposure, has been documented in a number of mammalian species. To probe the molecular mechanisms underlying this effect, the mouse would be a useful model; however, a previous study reported no conditioning ...
Ohinata Y - - 2000
This study investigates the correlation between the formation of reactive oxygen species (ROS) and auditory damage in noise-induced hearing loss. The noise exposure (4-kHz octave band, 115 dB SPL, 5 h) created permanent threshold shifts at frequencies from 2 to 20 kHz. The lipid peroxidation product, 8-isoprostane, was determined biochemically ...
Touchell D - - 2000
Factors affecting survival of embryos of Zizania palustris after exposure to liquid nitrogen were investigated. Moisture content was the most critical factor. Embryos desiccated to a moisture content between 0.36 and 0.56 g water per g dry weight had highest survival after liquid nitrogen exposure (56 +/- 4% and 52 ...
Wilken J A - - 2000
Arousal and anxiety responses to stressful stimulation are products of multiple factors that may include the physiological, behavioral, cognitive, affective, trait, and state components of our six-system model, as well as mediational and non-mediational perspectives. Within the context of this model, the present experiment examined the effects of prior exposure ...
Rao D - - 2000
Free radical injury has been implicated in cochlear damage resulting from exposure to high-intensity noise and due to carbon monoxide (CO) hypoxia. Although exposure to noise plus CO is common in occupational settings and noise-induced hearing loss (NIHL) is enhanced in the presence of CO, potential mechanisms resulting in auditory ...
Ou H C - - 2000
An anatomically based frequency-place map was created for the mouse using C57BL/CBA F1 hybrids by matching noise-induced lesions in the organ of Corti with permanent hearing losses as determined by auditory brainstem response (ABR) thresholds. Twenty-six mice developed 'notched' ABR threshold shifts after exposure to an octave band of noise ...
Sarnat J A - - 2000
We conducted a multi-pollutant exposure study in Baltimore, MD, in which 15 non-smoking older adult subjects (> 64 years old) wore a multi-pollutant sampler for 12 days during the summer of 1998 and the winter of 1999. The sampler measured simultaneous 24-hr integrated personal exposures to PM2.5, PM10, SO4(2-), O3, ...
Finneran J J - - 2000
A behavioral response paradigm was used to measure masked underwater hearing thresholds in two bottlenose dolphins and one beluga whale before and after exposure to impulsive underwater sounds with waveforms resembling distant signatures of underwater explosions. An array of piezoelectric transducers was used to generate impulsive sounds with waveforms approximating ...
Bohne B A - - 2000
PURPOSE: To determine if noise damage in the organ of Corti is different in the low- and high-frequency regions of the cochlea. MATERIALS AND METHODS: Chinchillas were exposed for 2 to 432 days to a 0.5 (low-frequency) or 4 kHz (high-frequency) octave band of noise at 47 to 95 dB ...
Walden B E - - 2000
A number of studies have demonstrated that magnesium, administered prophylactically, can reduce the amount of hearing loss resulting from noise exposure. This study explored the possible role of naturally occurring body magnesium concentration in susceptibility of soldiers to noise-induced hearing loss. Participants were 68 adult males who had received extensive ...
Chen G D - - 2000
Hair cell loss is often used as a histological correlate of hearing loss. However, the histological and the physiological data are not always well correlated. This paper investigates the use of succinate dehydrogenase (SDH) activity in the hair cells as a marker of cellular dysfunction and so the loss of ...
Schlundt C E - - 2000
A behavioral response paradigm was used to measure masked underwater hearing thresholds in five bottlenose dolphins and two white whales before and immediately after exposure to intense 1-s tones at 0.4, 3, 10, 20, and 75 kHz. The resulting levels of fatiguing stimuli necessary to induce 6 dB or larger ...
Boroojerdi B - - 2000
Long-term deprivation of visual input for several days or weeks leads to marked changes in the excitability and function of the occipital cortex. The time course of these changes is poorly understood. In this study, we addressed the question whether a short period of light deprivation (minutes to a few ...
McFadden S L - - 2000
Sound conditioning (pre-exposure to a moderate-level acoustic stimulus) can induce resistance to hearing loss from a subsequent traumatic exposure. Most sound conditioning experiments have utilized long-duration tones and noise at levels below 110 dB SPL as traumatic stimuli. It is important to know if sound conditioning can also provide protection ...
Wu T N - - 2000
Lead and noise, via different mechanisms, may damage hearing ability, and, in some cases, cause severe and irreversible damage. To explore possible independent and synergistic effects of lead and noise on auditory function, the authors conducted a cross-sectional study in two lead-battery manufacturing factories. Lead and noise were the two ...
Lee R C - - 2000
Electrical shock trauma tends to produce a very complex pattern of injury, mainly because of the multiple modes of frequency-dependent tissue-field interactions. Historically, Joule heating was thought to be the only cause of electrical injuries to tissue by commercial-frequency electrical shocks. In the last 15 years, biomedical engineering research has ...
Nageris Ben I. - - 2000
An association between noise exposure and vestibular function has long been suspected. Our wide experience in a major otologic outpatient clinic yielded six patients within the last seven years who presented with Meniere's disease and a history of long-term exposure to noise. Two of the cases are described in detail. ...
Syka J - - 2000
The effect of exposure to various types of noise (broadband, high-frequency or low-frequency) was studied in adult pigmented rats. Thresholds and amplitudes of middle latency responses (MLR) recorded from electrodes implanted on the surface of the auditory cortex were analyzed before and after noise exposure. Exposure to noise with intensities ...
Lataye R - - 2000
Combined exposure to both noise and aromatic solvents such as styrene is common in many industries. In order to study the combined effects of simultaneous exposure to both noise and styrene on hearing, male adult Long-Evans rats were exposed either to 750 ppm styrene alone, to a 97 dB SPL ...
Christensen K L - - 2000
The ICH guideline on photostability has proposed quinine monohydrochloride chemical actinometric system as a standard method for measuring light exposure during photostability testing. A change in the absorption at 400 nm of quinine monohydrochloride after light exposure corresponds to a defined dose of light. The present work investigated the effect ...
Muijser H. - - 2000
Four groups of rats (n=8 per group) were exposed to either 3000 ppm trichloroethylene (TCE) alone or to 95 dB SPL noise alone or to the combination of TCE and noise or to control conditions. Exposure was carried out 18 hours/day, 5 days/week for 3 weeks. Exposure to TCE alone ...
Khan M J - - 2000
Glutamate excitotoxicity is implicated in both the genesis of neural injury and noise-induced hearing loss (NIHL). Acoustic overstimulation may result in excessive synaptic glutamate, resulting in excessive binding to post-synaptic receptors and the initiation of a destructive cascade of cellular events, thus leading to neuronal degeneration and NIHL. The purpose ...
Fechter Laurence D. - - 2000
Hearing loss is the most common occupational disease in the United States with noise serving as the presumed causative agent in most instances; noise is identified as a prominent factor in approximately 10 million individuals in the United States with hearing impairments. Despite the characterisation of noise exposures that yield ...
Michael R - - 1999
PURPOSE: To investigate the effect of the interval between two, near-threshold exposures to ultraviolet radiation (UVR) on cataract development. METHODS: One eye of Sprague-Dawley rats was exposed twice to 4 kJ/m2 narrow band UVR (lambdaMAX=300 nm) for 15 min each. The interval between exposures was 0, 6, 24 or 48 ...
Sliney D H - - 1999
Epidemiological studies of the influence of environmental ultraviolet radiation (UVR) in the development of cataract, pterygium, droplet keratopathies and age-related macular degeneration have produced inconsistent findings. The lack of consistent results may be due largely to either incomplete or erroneous estimates of outdoor UV exposure dose. Geometrical factors dominate the ...
van der Kamp J J Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Vrije Universiteit, Van der Boechorststraat 9, 1081 BT Amsterdam, Amsterdam, The Netherlands, - - 1999
A pre-exposure, exposure, post-exposure design was used to assess the adaptation of the timing of a one-handed catch during telestereoscopic viewing. More specifically, it was examined whether the adaptation involved: (1) ignoring binocular sources of information and selecting other information, or (2) a recalibration of the coupling between the effected ...
Price G R - - 1999
Airbag deployment includes very intense acoustic stimulation, yet almost no tests of auditory hazard have been done with real ears. Therefore 32 anesthetized cats, positioned at the driver and passenger locations in a pickup truck, were exposed in pairs to one airbag deployment (electrically initiated). Hearing was tested at 1, ...
Hamernik R P - - 1999
Exposure of the auditory system to either continuous or interrupted nontraumatic noises, often collectively referred to as priming exposures, has been shown, in a number of experimental paradigms, to reduce the susceptibility of the auditory system to noise-induced hearing and sensory cell loss from a subsequent traumatic exposure. Using auditory ...
Mom T - - 1999
Cochlear ischemia induces a sensorineural hearing loss, in part through a fast functional impairment of outer hair cellls. Assuming that the cochlea is rendered fragile during ischemia and reperfusion and that stimulation itself can jeopardize its functional recovery, we used a model of reversible selective cochlear ischemia in Mongolian gerbils ...
Ohlemiller K K - - 1999
Reactive oxygen species (ROS) have been implicated in a growing number of neurological disease states, from acute traumatic injury to neurodegenerative conditions such as Alzheimer's disease. Considerable evidence suggests that ROS also mediate ototoxicant- and noise-induced cochlear injury, although most of this evidence is indirect. To obtain real-time assessment of ...
Kastak D - - 1999
Pure-tone sound detection thresholds were obtained in water for one harbor seal (Phoca vitulina), two California sea lions (Zalophus californianus), and one northern elephant seal (Mirounga angustirostris) before and immediately following exposure to octave-band noise. Additional thresholds were obtained following a 24-h recovery period. Test frequencies ranged from 100 Hz ...
Kujawa S G - - 1999
Sound conditioning, by chronic exposure to moderate-level sound, can protect the inner ear (reduce threshold shifts and hair cell damage) from subsequent high-level sound exposure. To investigate the mechanisms underlying this protective effect, the present study focuses on the physiological changes brought on by the conditioning exposure itself. In our ...
Mansfield J D - - 1999
Popular concern about widespread damage to the hearing from exposure to amplified music continues, although there has been little firm evidence of permanent effects in casual listeners. Measurement of transient evoked otoacoustic emissions (TEOAEs) provides a sensitive technique for testing outer hair cell (OHC) function, and was used in this ...
Graham C - - 1999
The neurophysiological effects of exposure to power-frequency magnetic fields at two occupationally-relevant intensities were evaluated in a single-blind study with 18 male and 18 female volunteers. Auditory brainstem (BAEP) and somatosensory (SEP) evoked potentials were recorded before, during and after field exposure (duration = 45 min, frequency = 60 Hz, ...
Burch J B - - 1999
The effects of occupational 60 Hz magnetic field and ambient light exposures on the pineal hormone, melatonin, were studied in 142 male electric utility workers in Colorado, 1995-1996. Melatonin was assessed by radioimmunoassay of its metabolite, 6-hydroxymelatonin sulfate (6-OHMS), in post-work shift urine samples. Personal magnetic field and light exposures ...
Kavaliers M - - 1999
The attenuation of opioid analgaesia is a well established effect of extremely low frequency (ELF) magnetic fields with light having a modulatory role in these effects such that when the ELF exposures are carried out in the dark, the inhibitory effects on analgesia are reduced. Here, we considered the light ...
Hamernik R P - - 1999
The auditory system 'toughened' by an interrupted noise exposure has been shown in several reports, to be less affected by (or protected from) a subsequent high level noise exposure. A group of chinchillas (n = 12) was exposed to an interrupted noise at 95 dB SPL, 0.5 kHz octave band, ...
Goel A - - 1999
Subtemporal craniotomy centred on the external ear canal and its basal extension, involving resection of the roots of the zygomatic arch, roof of the external ear canal and superior third to half of the mastoid bone was used to treat surgically 24 meningiomas located in the petroclival region, having their ...
Chen G D - - 1999
In previous studies from our lab, broadband noise induced hearing loss has been found to be potentiated by simultaneous carbon monoxide (CO) exposure. In the present study, octave-band noise induced auditory impairment was studied with the presence of CO at levels of 1500, 1200, 700, 500 and 300 ppm and ...
McFadden S L - - 1999
OBJECTIVE: To determine if chinchillas exhibit sex differences in 1) basic auditory sensitivity and 2) susceptibility to cochlear damage and hearing loss from high-level impulse noise. DESIGN: The auditory sensitivity of 73 chinchillas was assessed by measuring evoked potentials from electrodes implanted in the inferior colliculus (IC-EVPs) and cubic (2f1-f2) ...
Ahroon W A - - 1999
The auditory system, toughened by an interrupted noise exposure, has been shown in several reports to be less affected by (or protected from) a subsequent high-level noise exposure. Exposure to 115 dB peak SPL, 1 kHz narrow band (400 Hz) transients presented l/s, 6 h/day, to four groups of chinchillas ...
Gerhardt K J - - 1999
OBJECTIVE: To evaluate, in two separate experiments, the effects of intense noise exposures delivered to fetal sheep in utero during a time of rapid auditory development. DESIGN: In the first experiment, auditory brain stem response (ABR) thresholds to clicks and tone bursts were recorded from chronically instrumented fetal sheep in ...
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