BACKGROUND: Auditory steady-state responses (ASSR) is an objective method of hearing examination in clinic in recent years. ASSR has the frequency specificity as compared with previous auditory brainstem responses (ABR).OBJECTIVE: To investigate the accuracy of ASSR in objective hearing assessment.DESIGN: A case-control observation.SETTING: Department of Otorhinolaryngology, the First Affiliated Hospital of Sun Yat-sen University.PARTICIPANTS: The subjects in the normal hearing group were the 21 undergraduates (42 ears) were enrolled, they all had not any symptoms of ear disease, without history of noise exposure and disease of vestibule system, and they were normal in otoscopy. The outpatients and inpatients with neurosensory deafness were selected from the Department of Otorhinolaryngology, the First Affiliated Hospital of Sun Yat-sen University. All the children cases worn hearing aids, and had the speech ability, and cooperated in the examination. The main types included 6 ears of sudden deafness,8 ears of presbycusis, and 20 ears of neurosensory deafness due to other unknown causes. Central lesions were excluded by MR examination, and all the patients agreed with the enrollment. The results of pure-tone audiometry were all flat or descending audiogram. According to the severity of hearing damage, the patients were divided into mild deafness group (13ears), moderate deafness group (9 ears) and moderate-to-severe deafness group (12 ears).METHODS: ① The pure-tone audiometry was performed at the frequencies of 0.125-8 000 Hz in a sound insulation room. The auditory threshold grades of the subjects with normal hearing all accorded with the standards of GB-7583-87 expected value distribution. The average value of air-conduction auditory thresholds of pure-tone audiometry at the frequencies of 0.5, 1, 2 and 4 kHz was calculated. ② ASSR measurement was performed with the synchronous stimulation pattern in a sound and electromagnetic shielding room, including 8 points for both ears of the same stimulation intensity and the carrier frequency tones of 0.5, 1, 2 and 4 kHz respectively.③ ABR examination was performed by click sounds with sparse waves in a sound and electromagnetic shielding room, and insert earphones were used.The threshold results were judged according to the minimal stimulation sound intensity of the distinguishable Ⅴ wave. ③ The results of pure-tone audiometry were compared with those of ABR examination, and the results of ASSR measurement in different hearing groups were processed with analysis of variance, multi-classification discrimination based Bayes standard and q test.MAIN OUTCOME MEASURES: The thresholds of pure-tone audiometry, ASSR measurement and ABR examination, and the correct rate analyzed by the multi-classification discrimination based Bayes standard were mainly observed.RESULTS: The indexes of the 42 ears in the normal hearing group, 13, 9 and 12 ears in the mild, moderate and moderate-to-severe deafness groups were all involved in the analysis of results. ① The ABR values were accorded with the actual hearing levels, and the closest to the ASSR thresholds at 1-2 kHz; ASSR reflected induction rates at different frequencies were gradually decreased with the aggravation of hearing damage, and that at each frequency varied with the changes of hearing level, the induction rates of ASSR responses were all 100% for the subjects with normal hearing and patients with mild deafness, but those for the patients with moderate and moderate-to-severe deafness were decreased (0.5 kHz: 77.8%,92.8%; 4 kHz: 88.9%, 85.7%). At different frequencies, the ASSR thresholds in the moderate-to-severe deafness group were significantly higher than those in the normal hearing group (P ＜ 0.05). The ASSR thresholds at 0.5 and 4 kHz in the moderate-to-severe deafness group were significantly higher than those in the mild deafness group (P ＜ 0.05). The ASSR threshold at 2 kHz in the mild deafness group was significantly higher than that in the normal hearing group (P ＜ 0.05). The ASSR thresholds at 4 kHz in the everedeafness group were significantly higher than those in the normal hearing group and mild deafness group. ② The incorrect discriminations of actual pure-tone audiometry were analyzed with the interactive clustering discriminant analysis of ASSR measurement and actual pure-tone audiometry, and the results showed that the correct rate of discrimination was 100% in the normal hearing group; Only 1 of the 12 cases in the mild deafness group was incorrectly judged, and the correct rate was 92%; Only 1 of the 19 cases in the moderate deafness group was incorrectly judged, and the correct rate was 89%; the correct rate in the moderateto-severe deafness group was 83%.CONCLUSION: The results of ASSR measurement can detect the incorrect discrimination of objective hearing condition by taking the results of pure-tone audiometry as the standards. ASSR has an acceptable accuracy for deafness higher than mild level in estimating objective hearing, and it has a better prospect of application in practice.

Ibuprofen/ethyl-cellulose (EC)-polyvinylpyrrolidone (PVP) sustained-release composite particles were prepared by using supercritical CO2 anti-solvent technology. With drug loading as the main evaluation index, orthogonal experimental design was used to optimize the preparation process of EC-PVP/ibuprofen composite particles. The experiments such as encapsulation efficiency, particle size distribution, electron microscope analysis, infrared spectrum (IR), differential scanning calorimetry (DSC) and in vitro dissolution were used to analyze the optimal process combination. The orthogonal experimental optimization process conditions were set as follows: crystallization temperature 40 degrees C, crystallization pressure 12 MPa, PVP concentration 4 mgmL(-1), and CO2 velocity 3.5 Lmin(-1). Under the optimal conditions, the drug loading and encapsulation efficiency of ibuprofen/EC-PVP composite particles were 12.14% and 52.21%, and the average particle size of the particles was 27.621 microm. IR and DSC analysis showed that PVP might complex with EC. The experiments of in vitro dissolution showed that ibuprofen/EC-PVP composite particles had good sustained-release effect. Experiment results showed that, ibuprofen/EC-PVP sustained-release composite particles can be prepared by supercritical CO2 anti-solvent technology.

Objective To explore the eftect of SS31 peptide on autophagy after spinal cord injury (SCI) and possible mechanism.Methods Allen nethod was used to construct the spinal cord injury model in rats.Sprague-Dawley rats were randomly divided into sham surgery group (sham group),SCI group and SS31 peptide group,with 30 rats in each group.The sham group only received laminectomy.The rats in SCI group were sustained SCI and were given no intervention.The rats in SS31 group received SS31 peptide injection after SCI.Scores of Basso Beattie Bresnahan (BBB) motor functions were assessed at 6 h,1,3,7 and 14 d after the injury.The changes in related proteins of Beclin-1 and LC3-Ⅱ were also detected.Results Scores of BBB scale at 6 h and at days 1,3,7 and 14 after injury in SCI group (0,1.7 ±0.4,3.5 ±0.6,6.1 ±0.7,10.1 ±0.6) and SS31 peptide group (0,2.5 ±0.7,4.1 ±0.7,9.3 ±0.6,13.4 ±0.6) were lower than that in sham group (21 at all time points) (P ＜0.05).Scores of BBB scale at days 7 and 14 after injury in SS31 peptide group (9.3 ±0.6,13.4 ±0.6) was higher than that in SCI group (6.1 ± 0.7,10.1 ± 0.6) (P ＜ 0.05).There was no significant difference upon scores of BBB scale of SS31 peptide group at 6 h and at days 1 and 3 after injury (0,2.5 ±0.7,4.1 ± 0.7),compared with SCI group (0,1.7 ± 0.4,3.5 ± 0.6) (P ＞ 0.05).Compared with sham group,the expression of Beclin-1 in SCI group and SS31 peptide group was increased,reached a peak at day 3 (1.478 ± 0.030,1.841 ± 0.051),remained high level at day 7 (1.302 ± 0.049,1.551 ± 0.032) and showed high expression at day 14 (1.252 ±0.048,1.471 ± 0.062) (P ＜ 0.05).Compared with sham group,the expression of LC3-Ⅱ in SCI group and SS31 peptide group also increased,reached a peak at day 3 (0.348 ± 0.028,0.655 ± 0.052),remained high level at day 7 (0.301 ± 0.053,0.432 ± 0.052) and also showed high expression at day 14 (0.268 ± 0.049,0.371 ± 0.052) (P ＜ 0.05).The expressions of Beclin-1 and LC3-Ⅱ in SS31 peptide group at day 3 after injury were 1.841 ± 0.051 and 0.455 ± 0.052,higher than that in SCI group (1.478 ± 0.030,0.348 ± 0.028) (P ＜ 0.05).In SS31 peptide group at 6 h and days 1,7 and 14 after injury,the expressions of Beclin-1 (0.582 ± 0.028,0.723 ±0.049,1.551 ±0.032,1.471 ±0.062) and LC3-Ⅱ (0.172 ±0.031,0.256 ±0.051,0.432 ± 0.052,0.371 ± 0.052) had no significant difference in comparison with corresponding expressions of Beclin-1 (0.584 ±0.021,0.642 ±0.051,1.302 ±0.049,1.252 ±0.048) and LC3-Ⅱ (0.156 ± 0.019,0.184±0.050,0.301 ±0.053,0.268 ±0.049) in SCI group (P＞0.05).Conclusion SS31 peptide can improve motor function and enhance the autophagy of nerve cells after SCI in rats,which may be one of the mechanisms for SS31 peptide treating spinal cord injury.

Objective:To explore the strategy and experience for treating maxillofacial and cervical multi-space infection combined with descending necrotizing mediastinitis (DNM) via multidisciplinary team (MDT) collaboration.Methods:A total of 36 patients with maxillofacial and cervical multi-space infection complicated with DNM admitted to the First Affiliated Hospital of Zhengzhou University from July 2011 to July 2019 were included in the study. The clinical data of the patients were retrospectively analyzed, including gender, age, symptoms at admission, source of infection, preoperative and postoperative evaluation indicators, MDT strategy and prognosis.Results:There were 26 males and 10 females with an average age of (51.6±17.6) years (8-80 years). The course of disease before admission was (8.9±8.4) days (2-30 days). All patients were admitted with maxillofacial and neck swelling and pain as the main complaints. Odontogenic infection accounted for 39% (14/36), throat floor swelling and pain accounted for 25% (9/36) and unknown maxillofacial swelling accounted for 36% (13/36). There were 28 cases receiving surgical treatment, 26 cases were cured and discharged (72%), 10 cases died (28%). In the patients treated with multidisciplinary therapy (mainly by surgery), the white blood cell count, neutrophil percentage, C-reactive protein and procalcitonin levels were significantly improved compared with those at admission at each observation time point after operation ( P<0.05). The length of stay was positively correlated with the levels of C-reactive protein ( r=0.545, P<0.05) and procalcitonin ( r=0.504, P<0.05). The prognosis of patients treated with surgery (26/28) was better than that of patients without surgery (0/8) ( P<0.01). Conclusions:The patients with maxillofacial and cervical multi-space infection combined with DNM might be in critical condition. The surgical based MDT strategy has an important impact on the prognosis of patients. White blood cell count and other inflammatory indicators monitoring can effectively observe the changes of the patient′s condition.