Objective To investigate the spatiotemporal expression pattern of metabotropic glutamate receptor 4(mGluR4)in the mouse cochlear basilar membrane and its dynamic changes during postnatal development until hair cell synaptic maturation.Methods Ten healthy 3-month-old C57BL/6L wild-type mice(5 males,5 females,25～35 g)were bred to obtain offspring.Cochlear samples from postnatal days 1～30(P1～P30)were analyzed.Frequency-specific auditory brainstem response(ABR)thresholds were measured at 45.2,32.0,22.6,16.0,11.3,8.0,5.6,and 4.0 kHz in P12,P14,P16,P21,and P30 mice.Immunofluorescence assay combined with confocal laser scanning microscopy was used to scan cochlear whole-mount preparations.Spatiotemporal co-localization profiling of mGluR4 and synaptic markers Ctbp2 and Snap25 was observed,and quantitative comparisons of fluorescent puncta density were performed.Results ABR testing revealed undifferentiated waveforms in all P12 mice,while 70%of P14 mice exhibited well-defined Wave I.In P14,P16,P21 and P30,mice undergoing ABR testing,50%failed to exhibit ABR waveforms when stimulated by 45.2 kHz tones,and 87.5%showed no response to 32.0 kHz stimuli.Auditory response thresholds for other frequencies progressively decreased with increasing postnatal age.Immunolocalization demonstrated stronger mGluR4 expression in inner hair cells(IHCs)versus outer hair cells(OHCs).Distinct mGluR4 puncta were observed at IHC presynaptic active zones(co-localized with Snap25)as early as P11,but showed minimal overlap with CtBP2-labeled ribbons.Quantitative analysis revealed significantly higher mGluR4 puncta density at P30 compared to P14 synapses(P<0.05).Conclusion Postnatal upregulation of mGluR4 at IHC synaptic regions correlates with functional maturation.These findings suggest mGluR4 may modulate vesicular exocytosis regulation and exert pharmacological inhibition on glutamate release,potentially influencing synaptic plasticity during auditory pathway refinement.

Objective:To investigate the level of serum Omentin-1 in subjects with abdominal obesity, and to analyze the influencing factors of Omentin-1 and its relationship with body fat distribution, insulin resistance and metabolic parameters.Methods:A retrospective case-control study was conducted to analyze the clinical data of one hundred and fifty adults with abdominal obesity (BMI≥28 kg/m 2) who were randomly selected from Obesity Multidisciplinary Diagnosis and Treatment Center, Subei People's Hospital from Januray 2018 to December 2021. Meanwhile, 150 healthy adults were enrolled as a normal control group. Fasting serum Omentin-1 and glucose metabolism were measured, and homeostasis model assessment of insulin resistance index (HOMA-IR) was calculated. Body fat composition was measured by bioelectrical impedance analysis. The relationship between Omentin-1 and other variables were presented by the Pearson correlation coefficients. Stepwise regression model was used to analyze the influencing factors of Omentin-1. Results:The serum omentin-1 level of patients with abdominal obesity was (36.97±6.99) μg/L, that of normal control group was (72.35±6.09) μg/L. The difference between the two groups was statistically significant ( t=46.69, P<0.001). The body fat level of patients with abdominal obesity was (43.40±14.59) kg, that of normal control group was (13.78±4.13) kg. The difference between the two groups was statistically significant ( t=23.93, P<0.001). The fasting insulin of patients with abdominal obesity was 29.05 (22.01,34.60) pmol/L, that of normal control group was 127.90 (84.08,201.45) pmol/L. The difference between the two groups was statistically significant( Z=14.75, P<0.001). The HOMA-IR of patients with abdominal obesity was 0.87 (0.68,1.05), that of normal control group was 4.19 (2.77,7.31). The difference between the two groups was statistically significant ( Z=14.75, P<0.001). Pearson linear correlation analysis showed that serum omentin-1 levels were negatively correlated with BMI, waist circumference, waist-hip ratio (WHR), body fat, visceral Fat area (VFA), HOMA-IR, triglyceride, total cholesterol and low density lipoprotein cholesterol ( r=-0.825, -0.843, -0.756, -0.777, -0.835, -0.583, -0.429, -0.353, -0.503, -0.938, all P<0.001). Whereas, a significantly positive correlation was found between serum Omentin-1 levels and high density lipoprotein cholesterol ( r=0.528, P<0.001). Omentin-1 concentrations were not related to age or gender ( r=-0.093, -0.040; P=0.669, 0.489). In multiple linear stepwise regression analysis, only VFA remained significantly associated with Omentin-1 ( β=-0.026, t=-2.250, P=0.026). Conclusion:The level of serum omentin-1 in patients with abdominal obesity was significantly lower than that in normal subjects, and it was closely related to body fat distribution and insulin resistance. VFA is an independent influencing factor of serum omentin-1, which can be used as a biomarker of abdominal obesity related metabolic disorders.

Objective To analyze the quality control measures on urinary fluoride testing in the implementation,and to provide experience in quality control for testing activities.Method According to the Determination of Fluoride in Urine-Ion Selective Electrode Method (WS/T 89-1996),focusing on ways to complete testing all the samples in a short time,implementing internal quality control measures in the testing before,during and after the implementation by different ways as blank experiment,standard substance detection,personnel parallel experiment,paralleled detection,instrument comparison and sample test repeat,were carried out.Results The test results of blank experiment were lower than the lowest detection limit;the test results of standard material were within the scope of the standard reference,there was no significant difference between the mean value and the reference value (t =0.01,0.00,0.02,all P ＞ 0.05),|Z| values were all less than 1;the results of personnel parallel experiment,paralleled detection,instrument comparison test results and sample test repeat were not significantly different statistically (all P ＞ 0.05);the results of instrument comparison and sample test repeat were not significantly different statistically (t =0.129,0.034,all P ＞ 0.05).A total of 9 123 urine samples were tested,the geometric mean of urinery fluoride was 0.58 mg/L.Conclusion Different quality control measures should be implemented through all the testing,control personnel errors,instruments,and reagents,etc,to ensure the quality of the entire test results.