[Research on early warning model of the hearing loss of workers exposed to noise].

Objective: To explore the change of hearing threshold of workers exposed to noise, establish an individual-based hearing loss early warning model, accurately and differentiated the health of workers exposed to noise. Methods: In September 2019, all physical examination data of 561 workers exposed to noise from an enterprise were collected since their employment. Three indicators of average hearing threshold of the better ear, namely, at high frequency, 4000 Hz and speech frequency, were constructed. The generalized estimating equation (GEE) was used to adjust gender and age and establish the warning model of each indicator. Finally, sensitive indicators and warning models were screened according to AUC and Yoden index. Results: Among the 561 workers exposed to noise, 26 (4.6%) workers had hearing loss. The sensitivity indicators were the average hearing threshold at speech frequency ≥20 dB, high frequency ≥30 dB and 4000 Hz ≥25 dB. The AUC of each index was 0.602, 0.794 and 0.804, and the Youden indexes were 0.204, 0.588 and 0.608, respectively. In GEE of hearing loss warning models, high-frequency hearing threshold ≥20 dB and 4000 Hz hearing threshold ≥25 dB were the optimal models, with AUC of 0.862. Conclusion: Combined with the changes of individual hearing threshold over the years, can accurately assess the risk of individual hearing loss of workers exposed to noise.

[Synthesis of cell penetrating peptide decorated magnetic nanoparticles loading cisplatin for nasopharyngeal cancer therapy].

Objective:To synthesize cisplatin loaded and cell penetrating peptide TAT decorated magnetic nanoparticles and to observe the inhibiting effect in vitro on nasopharyngeal cancer therapy.Method：The aldehyde sodium alginate coated magnetic nanoparticles (ASA-MNPs) was prepared as the drug delivery system, which was covalently attached by PEGylation TAT (TAT-ASA-MNPs) via condensation of aldehyde with amino group and then coordinated with cisplatin (TAT-ASA-MNPs@CDDP). The complex was characterized by H-NMR and FT-IR. The cell penetrating ability and biocompatibility were observed by means of fluorescent tags. The inhibited effect on nasopharyngeal cancer CNE-2 cells was measured by cellular toxicity research and flow cytometry.Result：The H NMR and FT-IR of TAT-ASA-MNPs exhibited the characteristic peaks of TAT, PEG as well as ASA. The dynamic light scattering showed the hydrodynamic diameter of the complex was（145.9±1.5）nm. Zeta potential was（-21.66±1.24）mV and the drug loading rate was（25.03±3.05）%. Fluorescent labeling assay revealed that FITC marked TATASAMNPs was quickly taken up by CNE-2 cells. Cytotoxicity experiment on 293T cells displayed high survival rate (>70%) after cultured for 72h. Negative hemagglutination reflected decent biocompatibility. In vitro cytotoxicity test and cell apoptosis assay exhibited obvious inhibition on CNE-2 cell with TATASAMNPs@CDDP at low concentration of cisplatin compared to ASA-MNPs@CDDP (P<0.05).Conclusion：TAT-ASA-MNPs showed decent biocompatibility while distinctly inhibit CNE-2 cells in vitro study.