Objective To explore the application value of distortion product otoacoustic emission (DPOAE) and speech in noise(SIN) testing in occupational health surveillance of noise-exposed workers. Methods A total of 220 noise-exposed workers was selected as the study subjects using the convenient sampling method. The study subjects participated questionnaire survey, personal noise exposure assessment, acoustic immittance testing, pure tone audiometry (PTA), DPOAE and SIN testing. According to PTA results, workers were enrolled into a high-frequency hearing loss (HFHL) group and a non-HFHL group. Results The detection rate of HFHL among the study subjects was 41.4%, and the detection rate of speech-frequency hearing loss was 15.9%. Workers′ bilateral DPOAE response amplitudes and signal-to-noise ratios at frequencies of 2.0-8.0 kHz in the HFHL group were lower than those in the non-HFHL group (all P<0.05). The DPOAE amplitudes at frequencies of 1.0-8.0 kHz in both ears of the study subjects were negatively correlated with the PTA threshold (all P<0.01), and were negatively correlated with age (all P<0.01). The signal-to-noise ratio loss score was higher among worker in the HFHL group than in the non-HFHL group (P<0.01) and was positively correlated with PTA thresholds (P<0.05). Conclusion DPOAE and SIN testing can detect early cochlear outer hair cell impairment and reduction of noise-related speech recognition ability in noise-exposed workers and may serve as an effective supplementary tool to routine PTA in occupational hearing surveillance.

Objective To explore the research hotspots and development trends of pyrroloquinoline quinone(PQQ),and explore the research and application value of PQQ.Methods In this study,Web of Science was used as the retrieval database to search for literature related to PQQ published from 1985 to 2022,and VOSviewer software was used to include the keywords,countries and regions,journals,etc.Bibliometric analysis was performed on these literatures.Results A total of 1 512 articles were included,with an overall upward trend in the number of annual publications.The journal category with the highest number of publications was Biochemistry and Molecular Biology.Journal of Biological Chemistry had the highest total link strength.The high-frequency keywords mainly included dietary nutrition supplement,mitochondria,antioxidant,etc.The visualization results of countries and regions showed that although China started its research relatively late,and it had a strong connection intensity with other countries.Conclusion In recent years,the research heat of PQQ has gradually increased,and its antioxidant effects,improvement of mitochondrial function and action targets may be the hotpots of future research.PQQ still has broad development prospects,and will inject new vitality into the pharmaceutical and healthcare industry.

BACKGROUND: The proliferation of peripheral blood stem cells among peripheral blood mononuclear cells (PBMCs) invitro remains unclear. There is no optimal marker for tracing PBMCs transplanted in vivo.OBJECTIVE: To observe the degree of PBMC proliferation in stem cell medium by EdU labeling and to explore thefeasibility of EdU-labeled peripheral blood stem cells.METHODS: New Zealand rabbit PBMCs were isolated and cultured for 1 to 5 days in stem cell medium supplementedwith EdU. The cells were observed and counted at 0, 1, 2, 3, 4 and 5 days in culture. The cells were harvested at eachtime point and stained with EdU fluorescent reagents. Then, confocal microscopy and flow cytometry were used to detectEdU-labeled cells.RESULTS AND CONCLUSION: (1) Freshly isolated rabbit PBMCs were rounded and showed clear outline. After 1 dayculture, most of the cells were suspended in the medium, spherical or round. There were also a few cell clusters andadherent cells scattered in a triangle or polygon shape; after 2 days culture, more cell debris were observed, and mostcells were round; when cultured for 3-5 days, increased cell debris, smaller cell mass and decreased cell densitysignificantly were observed. (2) With the prolongation of culture time, the cell count decreased gradually. (3) Whencultured for 1 day, EdU labeled cells in red were scattered. The number of cells marked with EdU red label increasedsignificantly at day 2 and remained unchanged after 3 days of culture. At 5 days of culture, the number of red cellsmarkedly decreased; the highest positive rate of EdU-labeled cells was (2.38±0.10)% at 2 days after culture. To conclude,these results showed that the proportion of proliferating cells in rabbit PBMCs was very low. EdU is capable of labelingproliferative cells among PBMCs.