OBJECTIVE: To study the incidence of hearing loss at high frequency and the related influence factors among the flight cadets. METHOD: Using multi-stage sampling method, 312 flight cadets were randomly selected from grade 2011,2012,2013. The level of binaural hearing threshold at 4 kHz, 6 kHz, 8 kHz were measured by hearing-assistant evaluative apparatus. Whether or not have hearing loss was chosen as dependent variable. Territory, smoking, dietary habit, previous history of tinnitus, the noise exposure time, the vestibular function and the psychological quality were chosen as independent vailables. T test, ANOVA and accumulative logistic regression were performed to analyze the factors influence on hearing impairment by software SPSS 18.0. RESULT: The morbidity of hearing impairment among flight cadets was 18.9%. Results from single factor analysis showed that the levels of hearing thresholds at 4 kHz, 6 kHz frequency had statistically significant differences between smoking group and non-smoking group (P < 0.05). The levels of hearing thresholds at 4 kHz frequency had statistically significant differences between spicy diet group and not spicy diet group (P < 0.05). The levels of hearing thresholds at 4 kHz, 6 kHz, 8 kHz frequency had statistically significant differences among different strong noise exposure groups (P < 0.05), and that at a same frequency hearing loss increased when noise exposing increased. The levels of hearing thresholds at 4 kHz, 6 kHz frequency had statistically significant difference among different vestibular function groups (P < 0.05). Results of accumulative logistics regression showed that smoking and strong noise exposure were risk factors causing hearing impairment at 4 kHz frequency, and excellent vestibular function seemed to be a preventive factor. Smoking and strong noise exposure were also risk factors causing hearing impairment at 6 kHz frequency. CONCLUSION Hearing impairment appears higher morbidity among flight cadets, and it has statistical correlation with smoking, strong noise exposure and vestibular function.
Hearing Loss ; epidemiology ; Humans ; Logistic Models ; Male ; Risk Factors ; Space Flight ; Young Adult

To assess relationships between xanthine oxidase (XOD) and nephropathogenic infectious bronchitis virus (NIBV) infection, 240 growing layers (35 days old) were randomly divided into two groups (infected and control) of 120 chickens each. Each chicken in the control and infected group was intranasally inoculated with 0.2 mL sterile physiological saline and virus, respectively, after which serum antioxidant parameters and renal XOD mRNA expression in growing layers were evaluated at 8, 15 and 22 days post-inoculation (dpi). The results showed that serum glutathione peroxidase and superoxide dismutase activities in the infected group were significantly lower than in the control group at 8 and 15 dpi (p < 0.01), while serum malondialdehyde concentrations were significantly higher (p < 0.01). The serum uric acid was significantly higher than that of the control group at 15 dpi (p < 0.01). In addition, the kidney mRNA transcript level and serum activity of XOD in the infected group was significantly higher than that of the control group at 8, 15 and 22 dpi (p < 0.05). The results indicated that NIBV infection could cause the increases of renal XOD gene transcription and serum XOD activity, leading to hyperuricemia and reduction of antioxidants in the body.
Antioxidants ; Chickens ; Glutathione Peroxidase ; Hyperuricemia ; Infectious bronchitis virus* ; Kidney ; Malondialdehyde ; RNA, Messenger* ; Superoxide Dismutase ; Uric Acid ; Xanthine Oxidase* ; Xanthine*

Objective To investigate the diagnostic value of the T2WI gray scale ratio for Hashimoto's thyroiditis(HT).Methods The T2WI-iterative decomposition of water and fat with echo asymmetry and least square estimation(IDEAL)quantitation sequence water images of 22 HT cases were analyzed retrospectively.The gray scale ratio of the thyroid,sternocleidomastoid muscle,trachea cavity,and subcutaneous fat at the same layer were measured on the picture archiving and communication systems(PACS).The gray scale ratios of thyroid/sternocleidomastoid muscle(T/M),thyroid/trachea cavity(T/Tr),and thyroid/lipid(T/L)were calculated.The intraclass correlation coefficient(ICC)was used to evaluate the consistency among the measurements,and the optimal threshold for distinguishing HT from non-HT was determined via the receiver operating characteristic(ROC)curve.The Spearman correlation analysis was used to analyze the correlation between T/M,T/Tr,T/L ratios,and titers of thyroid peroxidase antibody(TPO-Ab)and thyroglobulin antibody(Tg-Ab),respectively.Results On the T2WI-IDEAL quantitation sequence water images,the(x)±s of T/M,T/Tr,T/L ratios for HT and non-HT were 2.17±0.47 and 1.62±0.21(t=14.90,P<0.001),9.40±3.24 and 4.87±2.93(t=11.42,P<0.001),1.66±0.32 and 1.21±0.31(t=7.51,P<0.001),respectively.The area under the curve(AUC)of T/M,T/Tr,and T/L ratios for diagnosing HT were 0.89,0.86,and 0.85,respectively;the optimal thresholds were 1.90,3.50,and 1.36,and the sensitivity and specificity were 72.7%and 100%,100%and 40.5%,95.5%and 29.7%,respectively.The T/M ratio had a moderate correlation with TPO-Ab(r=0.513,P<0.05),and T/Tr,T/L ratios had a mild correlation with TPO-Ab,respectively.Conclusion The T/M ratio in the T2WI gray scale ratio can quantitatively and objectively distinguish HT from non-HT to some extent and is correlated with TPO-Ab.It has extremely high specificity and holds promise as a non-invasive imaging method for the diagnosis of incidental HT.