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BMJ Case Reports Apr 2024Mycetoma is a chronic granulomatous infectious disease with a triad of subcutaneous swelling, discharging sinuses and the presence of granules. The infection may occur...
Mycetoma is a chronic granulomatous infectious disease with a triad of subcutaneous swelling, discharging sinuses and the presence of granules. The infection may occur following minor trauma or penetrating thorn injury. We report a case of a man in his 40s with a history of thorn prick 9 years ago, followed by the formation of painless discharging sinuses on the right foot for the past 2 years. Clinical, local epidemiological, histopathological examination and Gram stain confirmed the diagnosis of actinomycetoma. Prior to initiating the Welsh regimen, a pretreatment assessment of the patient's auditory function was conducted through pure tone audiometry, indicating the existence of pre-existing high-frequency bilateral sensorineural hearing loss. The patient was treated with linezolid as an alternative to amikacin, at a dosage of 600 mg two times per day, leading to complete resolution within 3 weeks. This underscores linezolid's efficacy as a safe and cost-effective alternative for actinomycetoma, without causing ototoxic side effects.
Topics: Humans; Linezolid; Male; Hearing Loss, Sensorineural; Mycetoma; Adult; Anti-Bacterial Agents; Treatment Outcome
PubMed: 38663898
DOI: 10.1136/bcr-2023-258686 -
Environmental Toxicology Jul 2024Platinum-based antineoplastic drugs, including cisplatin, carboplatin, and oxaliplatin, are widely used in the treatment of various cancers. Ototoxicity is a common...
Platinum-based antineoplastic drugs, including cisplatin, carboplatin, and oxaliplatin, are widely used in the treatment of various cancers. Ototoxicity is a common adverse effect of platinum-based drugs. Ototoxicity leads to irreversible hearing impairment. We hypothesize that different platinum-based drugs exhibit varying ototoxic concentrations, time effects, and ototoxic mechanisms. We tested this hypothesis by using a zebrafish model (pvalb3b: TagGFP) to assess the viability of hair cells collected from zebrafish larvae. Cisplatin, carboplatin, and oxaliplatin were administered at dosages of 100, 200, or 400 μM, and the ototoxic effects of these drugs were assessed 1, 2, or 3 h after administration. Fm4-64 and a TUNEL assay were used to label the membranes of living hair cells and to detect cell apoptosis, respectively. We observed that >50% of hair cells were damaged at 1 h after cisplatin (100 μM) exposure, and this ototoxic effect increased at higher dosages and over time. Owing to the smaller ototoxic effects of carboplatin and oxaliplatin, we conducted higher-strength and longer-duration experiments with these drugs. Neither carboplatin nor oxaliplatin was obviously ototoxic, even at 1600 μM and after 6 h. Moreover, only cisplatin damaged the membranes of the hair cells. Cell apoptosis and significantly increased antioxidant gene expression were observed in only the cisplatin group. In conclusion, cisplatin significantly damages sensory hair cells and has notable dosage and time effects. Carboplatin and oxaliplatin are less ototoxic than cisplatin, likely due to having different ototoxic mechanisms than cisplatin.
Topics: Animals; Zebrafish; Cisplatin; Oxaliplatin; Carboplatin; Ototoxicity; Antineoplastic Agents; Apoptosis; Hair Cells, Auditory; Larva
PubMed: 38661261
DOI: 10.1002/tox.24285 -
Molecular Neurobiology Apr 2024Aminoglycoside antibiotics, including gentamicin (GM), induce delayed ototoxic effects such as hearing loss after prolonged use, which results from the death of hair...
Aminoglycoside antibiotics, including gentamicin (GM), induce delayed ototoxic effects such as hearing loss after prolonged use, which results from the death of hair cells. However, the mechanisms underlying the ototoxicity of aminoglycosides warrant further investigation, and there are currently no effective drugs in the clinical setting. Herein, the therapeutic effect of the flavonoid compound rutin against the ototoxic effects of GM in zebrafish hair cells was investigated. Animals incubated with rutin (100-400 µmol/L) were protected against the pernicious effects of GM (200 µmol/L). We found that rutin improves hearing behavior in zebrafish, and rutin was effective in reducing the number of Tunel-positive cells in the neuromasts of the zebrafish lateral line and promoting cell proliferation after exposure to GM. Subsequently, rutin exerted a protective effect against GM-induced cell death in HEI-OC1 cells and could limit the production of cytosolic reactive oxygen species (ROS) and diminish the percentage of apoptotic cells. Additionally, the results of the proteomic analysis revealed that rutin could effectively inhibit the expression of necroptosis and apoptosis related genes. Meanwhile, molecular docking analysis revealed a high linking activity between the molecular docking of rutin and STAT1 proteins. The protection of zebrafish hair cells or HEI-OC1 cells from GM-induced ototoxicity by rutin was attenuated by the introduction of STAT1 activator. Finally, we demonstrated that rutin significantly improves the bacteriostatic effect of GM by in vitro experiments, emphasising its clinical application value. In summary, these results collectively unravel a novel therapeutic role for rutin as an otoprotective drug against the adverse effects of GM.
PubMed: 38653908
DOI: 10.1007/s12035-024-04179-4 -
Scientific Data Apr 2024Our sense of hearing is mediated by cochlear hair cells, of which there are two types organized in one row of inner hair cells and three rows of outer hair cells. Each...
Our sense of hearing is mediated by cochlear hair cells, of which there are two types organized in one row of inner hair cells and three rows of outer hair cells. Each cochlea contains 5-15 thousand terminally differentiated hair cells, and their survival is essential for hearing as they do not regenerate after insult. It is often desirable in hearing research to quantify the number of hair cells within cochlear samples, in both pathological conditions, and in response to treatment. Machine learning can be used to automate the quantification process but requires a vast and diverse dataset for effective training. In this study, we present a large collection of annotated cochlear hair-cell datasets, labeled with commonly used hair-cell markers and imaged using various fluorescence microscopy techniques. The collection includes samples from mouse, rat, guinea pig, pig, primate, and human cochlear tissue, from normal conditions and following in-vivo and in-vitro ototoxic drug application. The dataset includes over 107,000 hair cells which have been identified and annotated as either inner or outer hair cells. This dataset is the result of a collaborative effort from multiple laboratories and has been carefully curated to represent a variety of imaging techniques. With suggested usage parameters and a well-described annotation procedure, this collection can facilitate the development of generalizable cochlear hair-cell detection models or serve as a starting point for fine-tuning models for other analysis tasks. By providing this dataset, we aim to give other hearing research groups the opportunity to develop their own tools with which to analyze cochlear imaging data more fully, accurately, and with greater ease.
Topics: Animals; Mice; Guinea Pigs; Humans; Rats; Swine; Cochlea; Hair Cells, Auditory; Microscopy, Fluorescence; Machine Learning
PubMed: 38653806
DOI: 10.1038/s41597-024-03218-y -
Research Square Apr 2024Hearing impairment arises from the loss of either type of cochlear sensory hair cells. Inner hair cells act as primary sound transducers, while outer hair cells enhance...
Hearing impairment arises from the loss of either type of cochlear sensory hair cells. Inner hair cells act as primary sound transducers, while outer hair cells enhance sound-induced vibrations within the organ of Corti. Established models, such as systemic administration of ototoxic aminoglycosides, yield inconsistent and variable hair cell death in mice. Overcoming this limitation, we developed a method involving surgical delivery of a hyperosmotic sisomicin solution into the posterior semicircular canal of adult mice. This procedure induced rapid and synchronous apoptotic demise of outer hair cells within 14 hours, leading to irreversible hearing loss. The combination of sisomicin and hyperosmotic stress caused consistent and synergistic ototoxic damage. Inner hair cells remained intact until three days post-treatment, after which deterioration in structure and number was observed, culminating in cell loss by day seven. This robust animal model provides a valuable tool for otoregenerative research, facilitating single-cell and omics-based studies toward exploring preclinical therapeutic strategies.
PubMed: 38645253
DOI: 10.21203/rs.3.rs-4096027/v1 -
Otolaryngology--head and Neck Surgery :... Apr 2024Tinnitus is a multifactorial phenomenon with quality-of-life detriments for those affected by it. We aim to establish a relationship between subjective tinnitus severity...
OBJECTIVE
Tinnitus is a multifactorial phenomenon with quality-of-life detriments for those affected by it. We aim to establish a relationship between subjective tinnitus severity with objective audiometric data in the extended high frequency (EHF) from 9 to 16 khz and with distortion product otoacoustic emissions (DPOAE). We hypothesize that severe subjective tinnitus as measured by the Tinnitus Handicap Inventory (THI) does not correlate with increased hearing thresholds in the EHF range.
STUDY DESIGN
Prospective.
SETTING
Single Tertiary Care Center.
METHODS
Patients identified with tinnitus and normal hearing thresholds within standard frequency range (250-8000 Hz) were consented for participation. Those with underlying otologic disease, trauma, radiotherapy, or ototoxic drug use were excluded. The THI questionnaire was given to eligible patients and audiometric test results were collected. THI scores were categorized by severity groups. An n = 20 to 30 was determined to have an effect size of 0.7 with a significance level of P = .05.
RESULTS
THI and audiometric data were collected for 38 patients and categorized into mild (n = 18, 47.4%), moderate (n = 8, 21.1%), slight (n = 7, 18.4%), and severe (n = 5, 13.2%) tinnitus severity groups. Mean THI score was 32.3 ± 19.6 with a statistically significant difference in scores by assigned THI severity group (P < .01). There were no significant differences or linear relationship among hearing thresholds in EHF range or DPOAE stratified by subjective tinnitus group (P = .49, r = 0.10) CONCLUSION: Subjective tinnitus severity is not predictive of audiometric outcomes. This finding can be used as a counseling tool to help tinnitus patients manage symptoms, expectations, and overall treatment outcomes.
PubMed: 38639322
DOI: 10.1002/ohn.777 -
Frontiers in Molecular Neuroscience 2024
PubMed: 38633214
DOI: 10.3389/fnmol.2024.1401219 -
Journal of Cancer Survivorship :... Apr 2024This study aims to characterize patterns in ototoxicity monitoring and identify potential barriers to audiologic follow-up.
PURPOSE
This study aims to characterize patterns in ototoxicity monitoring and identify potential barriers to audiologic follow-up.
METHODS
We performed a single-institution retrospective cohort study on adult (≥ 18 years old) cancer patients treated with cisplatin from January 2014 to September 2021. Our primary outcomes were rates of baseline and post-treatment audiograms at the following time points: 3, 6, 12, and greater than 12 months. Time-to-event analyses were performed to describe additional insights to ototoxicity monitoring patterns.
RESULTS
Nine hundred fifty-five patients with cancer were included for analysis. The most common primary cancer sites were head and neck (64%), followed by cervical (24%). Three hundred seventy-three patients (39%) underwent baseline audiometric assessment, 38 patients (4%) received audiologic evaluation during chemotherapy, and 346 patients (36%) obtained at least one post-treatment audiogram. Audiologic follow-up was greatest within 3 months of completing chemotherapy (26%), but this tapered dramatically to less than 10% at every other post-treatment time point. Patients with head and neck cancer achieved higher rates of audiologic follow-up at every time point than patients with non-head and neck cancer except for during treatment.
CONCLUSIONS
Ototoxicity monitoring is an inconsistent practice, particularly during chemotherapy and for long-term surveillance of hearing loss. Patients with non-head and neck cancer may be at increased risk for loss of audiologic follow-up.
IMPLICATIONS FOR CANCER SURVIVORS
Cisplatin ototoxicity is a common occurrence that can be effectively managed with auditory rehabilitation. Therefore, referrals to audiology and counseling on treatment-related ototoxicity are recommended throughout chemotherapy and cancer survivorship.
PubMed: 38630333
DOI: 10.1007/s11764-024-01586-3 -
Redox Report : Communications in Free... Dec 2024Cisplatin is widely employed in clinical oncology as an anticancer chemotherapy drug in clinical practice and is known for its severe ototoxic side effects. Prior...
Cisplatin is widely employed in clinical oncology as an anticancer chemotherapy drug in clinical practice and is known for its severe ototoxic side effects. Prior research indicates that the accumulation of reactive oxygen species (ROS) plays a pivotal role in cisplatin's inner ear toxicity. Hesperidin is a flavanone glycoside extracted from citrus fruits that has anti-inflammatory and antioxidant effects. Nonetheless, the specific pharmacological actions of hesperidin in alleviating cisplatin-induced ototoxicity remain elusive. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) is a critical mediator of the cellular oxidative stress response, is influenced by hesperidin. Activation of Nrf2 was shown to have a protective effect against cisplatin-induced ototoxicity. The potential of hesperidin to stimulate Nrf2 in attenuating cisplatin's adverse effects on the inner ear warrants further investigation. This study employs both and models of cisplatin ototoxicity to explore this possibility. Our results reveal that hesperidin mitigates cisplatin-induced ototoxicity by activating the Nrf2/NQO1 pathway in sensory hair cells, thereby reducing ROS accumulation, preventing hair cell apoptosis, and alleviating hearing loss.
Topics: Humans; Cisplatin; Hesperidin; NF-E2-Related Factor 2; Ototoxicity; Reactive Oxygen Species; Cell Line; Antineoplastic Agents; Hair Cells, Auditory; Apoptosis
PubMed: 38629504
DOI: 10.1080/13510002.2024.2341470 -
The Journal of Antimicrobial... Jul 2024Aminoglycosides (AGs) are important antibiotics in the treatment of Gram-negative sepsis. However, they are associated with the risk of irreversible sensorineural...
BACKGROUND
Aminoglycosides (AGs) are important antibiotics in the treatment of Gram-negative sepsis. However, they are associated with the risk of irreversible sensorineural hearing loss (SNHL). Several genetic variants have been implicated in the development of ototoxicity.
OBJECTIVES
To evaluate the pharmacogenetic determinants of AG-related ototoxicity.
METHODS
This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses and was registered on Prospero (CRD42022337769). In Dec 2022, PubMed, Cochrane Library, Embase and MEDLINE were searched. Included studies were those reporting original data on the effect of the AG-exposed patient's genome on the development of ototoxicity.
RESULTS
Of 10 202 studies, 31 met the inclusion criteria. Twenty-nine studies focused on the mitochondrial genome, while two studied the nuclear genome. One study of neonates found that 30% of those with the m.1555A > G variant failed hearing screening after AG exposure (level 2 evidence). Seventeen additional studies found the m.1555A > G variant was associated with high penetrance (up to 100%) of SNHL after AG exposure (level 3-4 evidence). Nine studies of m.1494C > T found the penetrance of AG-related SNHL to be up to 40%; however, this variant was also identified in those with SNHL without AG exposure (level 3-4 evidence). The variants m.1005T > C and m.1095T > C may be associated with AG-related SNHL; however, further studies are needed.
CONCLUSIONS
This review found that the m.1555A > G and m.1494C > T variants in the MT-RNR1 gene have the strongest evidence in the development of AG-related SNHL, although study quality was limited (level 2-4). These variants were associated with high penetrance of a SNHL phenotype following AG exposure.
Topics: Humans; Aminoglycosides; Ototoxicity; Anti-Bacterial Agents; Pharmacogenetics; Hearing Loss, Sensorineural
PubMed: 38629462
DOI: 10.1093/jac/dkae106