Dataset Information

Effects of co-exposure to CS2 and noise on hearing and balance in rats: continuous versus intermittent CS2 exposures.

ABSTRACT: Background:Carbon disulfide (CS2) exacerbates the effect of noise on hearing, and disrupts the vestibular system. The goal of this study was to determine whether these effects are also observed with intermittent CS2 exposure. Methods:Rats were exposed for 4?weeks (5?days/week, 6?h/day) to a band noise at 106?dB SPL either alone or combined with continuous (63?ppm or 250?ppm) or intermittent (15?min/h or 2?×?15 min/h at 250?ppm) CS2. Hearing function was assessed by measuring distortion product otoacoustic emissions (DPOAEs); balance was monitored based on the vestibulo-ocular reflex (VOR). Functional measurements were performed before, at the end of exposure and 4?weeks later. Histological analyses of the inner ear were also performed following exposure and after the 4-week recovery period. Results:The results obtained here confirmed that CS2 exposure exerts two differential temporary effects on hearing: (1) it attenuates the noise-induced DPOAE decrease below 6?kHz probably through action on the middle ear reflex when exposure lasts 15?min per hour, and (2) continuous exposure to 250?ppm for 6?h extends the frequency range affected by noise up to 9.6?kHz (instead of 6?kHz with noise alone). With regard to balance, the VOR was reversibly disrupted at the two highest doses of CS2 (2?×?15?min/h and continuous 250?ppm). No morphological alterations to the inner ear were observed. Conclusion:These results reveal that short periods of CS2 exposure can alter the sensitivity of the cochlea to noise at a dose equivalent to only 10 times the short-term occupational limit value, and intermittent exposure to CS2 (2?×?15?min/h) can alter the function of the vestibular system.

SUBMITTER: Chalansonnet M

PROVIDER: S-EPMC7216478 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Effects of co-exposure to CS<sub>2</sub> and noise on hearing and balance in rats: continuous versus intermittent CS<sub>2</sub> exposures.

Chalansonnet Monique M Carreres-Pons Maria M Venet Thomas T Thomas Aurélie A Merlen Lise L Boucard Stéphane S Cosnier Frédéric F Nunge Hervé H Bonfanti Elodie E Llorens Jordi J Campo Pierre P Pouyatos Benoît B

Journal of occupational medicine and toxicology (London, England) 20200511

<h4>Background</h4>Carbon disulfide (CS<sub>2</sub>) exacerbates the effect of noise on hearing, and disrupts the vestibular system. The goal of this study was to determine whether these effects are also observed with intermittent CS<sub>2</sub> exposure.<h4>Methods</h4>Rats were exposed for 4 weeks (5 days/week, 6 h/day) to a band noise at 106 dB SPL either alone or combined with continuous (63 ppm or 250 ppm) or intermittent (15 min/h or 2 × 15 min/h at 250 ppm) CS<sub>2</sub>. Hearing functio ...[more]

PMID: 32426022

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Project description:BackgroundCastration resistance occurs in most patients with metastatic hormone-sensitive prostate cancer who are receiving androgen-deprivation therapy. Replacing androgens before progression of the disease is hypothesized to prolong androgen dependence.MethodsMen with newly diagnosed, metastatic, hormone-sensitive prostate cancer, a performance status of 0 to 2, and a prostate-specific antigen (PSA) level of 5 ng per milliliter or higher received a luteinizing hormone-releasing hormone analogue and an antiandrogen agent for 7 months. We then randomly assigned patients in whom the PSA level fell to 4 ng per milliliter or lower to continuous or intermittent androgen deprivation, with patients stratified according to prior or no prior hormonal therapy, performance status, and extent of disease (minimal or extensive). The coprimary objectives were to assess whether intermittent therapy was noninferior to continuous therapy with respect to survival, with a one-sided test with an upper boundary of the hazard ratio of 1.20, and whether quality of life differed between the groups 3 months after randomization.ResultsA total of 3040 patients were enrolled, of whom 1535 were included in the analysis: 765 randomly assigned to continuous androgen deprivation and 770 assigned to intermittent androgen deprivation. The median follow-up period was 9.8 years. Median survival was 5.8 years in the continuous-therapy group and 5.1 years in the intermittent-therapy group (hazard ratio for death with intermittent therapy, 1.10; 90% confidence interval, 0.99 to 1.23). Intermittent therapy was associated with better erectile function and mental health (P<0.001 and P=0.003, respectively) at month 3 but not thereafter. There were no significant differences between the groups in the number of treatment-related high-grade adverse events.ConclusionsOur findings were statistically inconclusive. In patients with metastatic hormone-sensitive prostate cancer, the confidence interval for survival exceeded the upper boundary for noninferiority, suggesting that we cannot rule out a 20% greater risk of death with intermittent therapy than with continuous therapy, but too few events occurred to rule out significant inferiority of intermittent therapy. Intermittent therapy resulted in small improvements in quality of life. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT00002651.).

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Dataset Information

Effects of co-exposure to CS2 and noise on hearing and balance in rats: continuous versus intermittent CS2 exposures.

Publications

Effects of co-exposure to CS<sub>2</sub> and noise on hearing and balance in rats: continuous versus intermittent CS<sub>2</sub> exposures.

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