Canavan Disease ; chemically induced ; complications ; Hearing Loss, Sudden ; etiology ; Heroin ; poisoning ; Humans ; Male ; Middle Aged

In this article, current status of noise exposure in workplaces, trend of workers with noise-induced hearing loss (NIHL), and prevalence of NIHL in workers by industry and job category in Korea were reviewed. In addition, trends of research on the audiological effects such as hearing loss from noise and occupational hearing loss from non-noise in Korea were addressed through reports in industrial audiology. Though noise exposure level has improved, noise still shows the highest rate of cases exceeding exposure limit among workplace hazards. NIHL is the most common occupational disease except work-related disease such as musculoskeletal disorders and cerebrovascular diseases, and NIHL prevalence is thought to be much higher than reported in official publications. Noise affecting hearing comes from various sources such as workplaces, military settings, areas with exposure to high noise, and specific noise sources. There is also occupational hearing loss by non-noise including chemicals such as organic solvents and heavy metals, barotrauma, and trauma due to welding spark. Noise affects daily life through audiological effects such as hearing loss and tinnitus, non-audiological physical effects (e.g., cardiovascular), and psychosocial and behavioral effects. Development of systematic and comprehensive hearing conservation programs for lowering the noise level in workplaces and preventing the NIHL, and preparation of technological, administrative system for its settlement at workplace are urgently needed.
Hearing Loss/*chemically induced ; Hearing Loss, Noise-Induced/*epidemiology ; Humans ; Noise, Occupational/*adverse effects ; Occupational Diseases/chemically induced/*epidemiology/*etiology ; Occupational Exposure/adverse effects ; Prevalence ; Republic of Korea/epidemiology ; Tinnitus/epidemiology

OBJECTIVETo observe the alterations of auditory brainstem response (ABR) in guinea pigs with gentamicin-induced hearing loss under awake and anesthetic conditions.

METHODSWe recorded the ABR in 20 normal guinea pigs and 20 with gentamicin-induced hearing loss before and after anesthesia for statistical analysis.

RESULTSNo significant difference was observed in the waveform, response threshold (RT), I and III peak latencies (PL), I-III interpeak latencies (IPL) of ABR between awake and anesthetic conditions in normal guinea pigs (P>0.05), nor did gentamicin-induced hearing loss showed obvious impact on the ABR parameters (P>0.05).

CONCLUSIONNo significant ABR alterations occur under awake and anesthetic conditions in either normal guinea pigs or those with hearing loss, therefore ABR test can be performed without anesthesia to ensure the success and error minimization of the experiment.

Anesthesia ; Animals ; Evoked Potentials, Auditory, Brain Stem ; physiology ; Gentamicins ; Guinea Pigs ; Hearing Loss, Bilateral ; chemically induced ; physiopathology ; Random Allocation ; Wakefulness

Sodium bromate is a strong oxidant used as a neutralizing solution in hair permanents, as well as an auxiliary agent in printing and dyeing. Accidental or deliberate ingestion of bromate solution has rarely been reported in Korea. The clinical manifestations of bromate intoxication are vomiting, diarrhea, central nervous system symptoms, oliguric or non-oliguric acute kidney injury, hemolytic anemia, and deafness; most of these manifestations are reversible, with the exception of renal failure and deafness. Here, we report on two patients who demonstrated distinct clinical progressions. In the first case, a 16-year-old woman was successfully treated with hemodialysis and recovered renal function without hearing loss. However, in the second case, delayed hemodialysis resulted in persistent renal failure and hearing loss in a 77-year-old woman. This suggests that emergency therapeutic measures, including hemodialysis, should be taken as soon as possible, as the rapid removal of bromate may be essential to preventing severe intoxication and its sequelae.
Acute Kidney Injury/*chemically induced/therapy ; Adolescent ; Aged ; Bromates/*toxicity ; Fatal Outcome ; Female ; Hearing Loss ; Humans ; Kidney Failure, Chronic/*therapy ; Renal Dialysis ; Sodium Compounds/*toxicity

OBJECTIVETo study the protective effect of local gene therapy with adeno-associated virus (AAV)-mediated neurotrophin-3 (NT-3) on the function and morphology of the cochlea of guinea pigs with gentamicin-induced hearing loss.

METHODSHearing loss was induced with gentamicin (80 mg.kg(-1).day(-1) injected intramuscularly) in 18 pigmented guinea pigs 4 days prior to gene transfer. The guinea pigs were then divided into groups A, B, and C for AAV-mediated NT-3 gene transfer (n=7), AAV infection (n=7) or no particular intervention (n=4), respectively. Mini-Osmotic pump were implanted in either side of the ears in groups A and B, and the guinea pigs were injected with gentamicin (80 mg.kg(-1).day(-1)) intramuscularly since the operation day for 10 consecutive days. In group C, only gentamicin was administrated. Before and 14 days after gentamicin administration, auditory brainstem response audiometry (ABR) and distort-product otoacoustic emissions (DPOAE) were recorded, and the animals sacrificed to observe the morphological changes of the cochlear microscopically.

RESULTSCompared with groups B and C, the animals in group A showed better auditory ability (ABR and DPOAE) and significantly higher surviving rate of the outer hair cells (P<0.05).

CONCLUSIONAAV-mediated NT-3 gene transfer may protect and repair the cochlear hair cells and auditory function damaged by aminoglycoside ototoxicity in guinea pigs, and aseptic procedure is of vital importance in cochlear local gene therapy.

Animals ; Cochlea ; physiopathology ; Dependovirus ; genetics ; metabolism ; Genetic Therapy ; Gentamicins ; adverse effects ; Guinea Pigs ; Hearing Loss ; chemically induced ; therapy ; Neurotrophin 3 ; therapeutic use

Anemia, Hemolytic ; chemically induced ; diagnosis ; Ceftriaxone ; adverse effects ; Child ; Cochlear Implantation ; adverse effects ; Hearing Loss, Sensorineural ; surgery ; Humans ; Male ; Vestibular Aqueduct

Animals ; Antineoplastic Agents ; toxicity ; Cisplatin ; toxicity ; Drugs, Chinese Herbal ; pharmacology ; Hearing Loss ; chemically induced ; Male ; Mice ; Mice, Inbred Strains ; Salvia miltiorrhiza

Mitochondrial DNA mutations are one of the most important causes of sensorineural hearing loss. A1555G and C1494T mutations of mitochondrial 12S rRNA gene are the molecular basis for aminoglycoside hyper- sensitivity and can lead to aminoglycoside-induced hearing loss. Primary mutations in tRNA such as tRNA(Ser(UCN))7472insC are associated with syndromic hearing loss. While other mutations such as tRNA"(Se(UCN) )G7444A were considered synergy with the primary RNA mutations, modulating the phenotypic manifestation. This review de- scribes a detailed summary of hearing loss associated with mtDNA mutations and/or aminoglycoside antibiotics, and provides the possible molecular mechanisms in deafness expression.
Aminoglycosides ; adverse effects ; Anti-Bacterial Agents ; adverse effects ; DNA, Mitochondrial ; genetics ; Hearing Loss, Sensorineural ; chemically induced ; genetics ; Humans ; Mutation ; RNA, Ribosomal ; genetics

A pregnant female taken realgar because of superstition, which caused the baby congenital deafness. Auditory test indicated that bilateral auditory brainstem response (ABR) hearing threshold level was greater than 90 dB nHL and auditory steady state response (ASSR) hearing level ranging from 0.5 kHz to 4 kHz was beyond 110 dB HL. Temporal bone CT showed that bilateral cochlear and semicircular canal malformations, with internal auditory canal broadened.
Arsenicals ; adverse effects ; Evoked Potentials, Auditory, Brain Stem ; Female ; Hearing Loss, Sensorineural ; chemically induced ; congenital ; Hearing Tests ; Humans ; Infant ; Maternal Exposure ; adverse effects ; Pregnancy ; Semicircular Canals ; pathology ; Sulfides ; adverse effects ; Temporal Bone ; pathology

The aim of this study was to determine the effects of transplanted neural differentiated human mesenchymal stem cells (hMSCs) in a guinea pig model of auditory neuropathy. In this study, hMSCs were pretreated with a neural-induction protocol and transplanted into the scala tympani of the guinea pig cochlea 7 days after ouabain injury. A control model was made by injection of Hanks balanced salt solution alone into the scala tympani of the guinea pig cochlea 7 days after ouabain injury. We established the auditory neuropathy guinea pig model using 1 mM ouabain application to the round window niche. After application of ouabain to the round window niche, degeneration of most spiral ganglion neurons (SGNs) without the loss of hair cells within the organ of Corti and increasing the auditory brain responses (ABR) threshold were found. After transplantation of neural differentiated hMSCs, the number of SGNs was increased, and some of the SGNs expressed immunoreactivity with human nuclear antibody under confocal laser scanning microscopy. ABR results showed mild hearing recovery after transplantation. Based on an auditory neuropathy animal model, these findings suggest that it may be possible to replace degenerated SGNs by grafting stem cells into the scala tympani.
Animals ; Cardiotonic Agents/toxicity ; Cochlea/drug effects/pathology ; Disease Models, Animal ; Female ; Guinea Pigs ; Hearing Loss, Central/chemically induced/pathology/*therapy ; Humans ; *Mesenchymal Stem Cell Transplantation ; Mesenchymal Stem Cells/*cytology ; Neurogenesis ; Ouabain/toxicity ; Spiral Ganglion/pathology ; Transplantation, Heterologous