OBJECTIVES: To propose a single repetition time (TR) quantitative magnetic susceptibility imaging method for the lumbar spine using bipolar readout gradient, and compare the quantitative magnetic susceptibility measurement using single TR and dual TR methods for the lumbar spine with different bone densities. METHODS: A translation correction method was proposed to correct spatial misalignment along the frequency encoding direction between positive and negative gradient readout images, and the phase difference between the images was eliminated using a phase correction method. The data of lumbar vertebrae L1-L5 were collected using single TR and dual TR methods from 6 normal individuals, 2 patients with osteopenia, and 2 patients with osteoporosis. The magnetic susceptibility map was reconstructed, the quantitative results of single TR before and after correction were compared with those of the dual TR method. RESULTS: The linear regression result of the lumbar spine magnetic susceptibility values obtained by the single TR method before calibration and the dual TR method is Y=0.64*X-11.61. The linear regression result of the lumbar spine magnetic susceptibility values corrected by the single TR method and the dual TR method is Y=1.03*X+0.25. The results of the corrected single TR method were highly consistent with those of the dual TR method, and the calibrated single TR method could effectively distinguish osteopenia and osteoporosis patients from normal individuals. CONCLUSIONS The calibrated single TR bipolar readout gradient method can generate artifact-free lumbar spine quantitative magnetic susceptibility distribution maps and reduce data acquisition time by 50%.
Humans ; Lumbar Vertebrae/pathology* ; Magnetic Resonance Imaging/methods* ; Female ; Middle Aged ; Male ; Osteoporosis/diagnosis* ; Adult ; Bone Density ; Aged ; Bone Diseases, Metabolic/diagnosis*

Objective To design and test a device which is capable of accurately measuring and dynamically adjusting the axial pressure at the fracture end in real-time.Methods Upon completion of the design,the pressure measurement and adjustment device was implemented in a canine tibial fracture external fixation model.A pressure sensor was mounted at the fracture end,and the displayed values of the pressure sensor were used as the standard for comparison.The relationship between the displayed values of the measurement and adjustment device and the pressure sensor under identical conditions was examined.Results The device was utilized in external fixation models of tibial fractures in five beagles.A linear correlation was observed between the displayed values of the device and the pressure sensor at the fracture end.The measurement values from the device could be transformed into fracture end pressure through the application of coefficients,thereby facilitating accurate measurement and dynamic adjustment of the fracture end pressure.Conclusion The pressure measurement and adjustment device at the fracture end is easy to operate,enabling precise measurement and dynamic regulation of the pressure at the fracture end.It is well-suited for animal experiments aimed at investigating the impact of axial compression on fracture healing,demonstrating promising potential for experimental applications.

Objective:To design an improved lamina hook system and compare its biomechanical properties with traditional lamina hook system in fixation of lumbar spondylolysis.Methods:The thin layer CT data of the lumbosacral vertebrae of 20 healthy young male servicemen who underwent physical examination in the outpatient department of the 940th Hospital of Joint Logistics Support Force of PLA from January 2021 to August 2022 were collected. The age of the subjects was 20-30 years [(25.0±3.0)years]. A 3-dimensional model of the L 5 vertebral body was constructed using the 3-dimensional modeling software. The new improved lamina hook was designed according to the measurements including the thickness of the middle area, the longest longitudinal diameter, the curvature radius of the lower edge, the angle between the upper and lower tail ends, the thickness of the lower edge, and the longest diameter of the lower edge of the bilateral L 5 vertebral plates. One serviceman was selected from the aforementioned group to construct a linear finite element model of segments L 4-S using the 3-dimensional virtual software (normal model, model A), based on which, the L 5 bilateral spondylolysis model (model B), improved lamina hook model (model C) and traditional lamina hook models (model D) were designed. By constraining both sides of the sacrum and applying a longitudinal load of 400 N on the L 4 vertebral body, the upper 1/3 gravity of the body was simulated, and with a bending moment of 10 N·m along the X, Y, and Z directions, motions of forward flexion, backward extension, lateral bending, rotation, etc were simulated. The range of motion of segment L 4/5 and L 5/S 1 of model A was evaluated and compared with the findings of the previous researches to verify its effectiveness. The overall range of motion of models A, B, C, and D, the range of motion of segment L 4/5 and L 5/S 1, the maximum overall displacement, the maximum displacement and stress of the isthmus, the stress distribution and maximum stress of internal fixation of models C and D, and the stress distribution and maximum stress of the vertebral body of models C and D were compared. Results:(1) During forward flexion, backward extension, lateral bending and rotation, the range of motion of model A was 5.01°, 4.03°, 3.91° and 1.42° in segment L 4/5, and was 4.62°, 2.51°, 2.40° and 1.23° in segment L 5/S 1. (2) The overall range of motion, range of motion of segment L 4/5 and L 5/S 1 and maximum overall displacement of models A, C, and D were similar in axial compression, forward flexion, backward extension, left bending, and left rotation, while those of model B were significantly increased. (3) There was no significant difference in the maximum displacement of the isthmus of models A, C, and D under different motion modes, while the maximum displacement of model B in the isthmus was significantly larger than that of models A, C, and D, especially during rotation, increased by 295%, 277%, and 276% respectively. The maximum stress of the isthmus of model C was 0.938 MPa, 1.698 MPa, 0.410 MPa, 2.775 MPa, and 1.554 MPa respectively. The maximum stress in the isthmus of model D was 0.590 MPa, 1.297 MPa, 0.520 MPa, 3.088 MPa, and 2.072 MPa respectively. The maximum stress of the isthmus of models C and D was similar during axial compression and forward flexion, while the stress of the isthmus of model C was smaller than that of model D during backward extension, lateral bending, and rotation, decreased by 21.1%, 10.2%, and 25.0% respectively compared with model D. (4) The maximum stress of internal fixation in models C and D during forward flexion, backward extension, left bending, and left rotation was 135.220 MPa, 130.180 MPa, 200.940 MPa and 306.340 MPa respectively, and was 131.840 MPa, 112.280 MPa, 349.980 MPa and 370.140 MPa respectively. The maximum stress of internal fixation in the two models of internal fixation during forward flexion and backward extension was similar, while it was decreased by 42.6% and 17.2% in model C during left bending and left rotation, compared with model D. (5) The maximum stress of the vertebral body during forward flexion, backward extension, left bending, and left rotation was 79.787 MPa, 36.857 MPa, 37.943 MPa and 96.965 MPa respectively in model C, but was 80.104 MPa, 64.236 MPa, 196.010 MPa and 193.020 MPa respectively in model D. The maximum stress of models C and D was all distributed in the contact area with the internal fixation, and especially during backward extension, left bending, and left rotation, when it was reduced by 42.6%, 80.6%, and 49.8% of model C respectively, compared with that of model D. Conclusions:The improved laminar hook is more consistent with the Chinese anatomized structure of the lamina. Compared with the traditional lamina hook system, the improved lamina hook system can effectively reduce the displacement in all directions and range of motion of lumbar spondylolysis, therefor can significantly reduce the stress of internal fixation and vertebral body and has better biomechanical performance.

Humans ; Inflammatory Bowel Diseases/drug therapy* ; Interleukin-6/therapeutic use*

Medical microbiology experiment is faced with many problems in online teaching. This study adopts the teaching mode of online live broadcast + operation video + virtual experiment, and make up the operation gap to some extent through operation video and virtual experiment. The mode of assessment is subjective thinking question (closely following the operation process) + experiment design + literature review (focusing on the key technology or new technology of clinical assessment that cannot be carried out due to the limitation of conditions in traditional experiments, such as mass spectrometry, fluorescence quantitative PCR, and G-test), and it is helpful to understand students' mastery of teaching objectives, and the ability of comprehensive application and innovative thinking. The student questionnaire shows that most students hold a positive attitude towards the online experimental teaching mode, and the quality of students' homework shows that most students have a good learning effect.

Objective:To investigate the effect of radiofrequency radiation (RF) from 5G mobile phone communication frequency bands (3.5 GHz and 4.9 GHz) on the permeability of the blood-brain barrier (BBB) in mice.Methods:A total of 24 healthy adult male C57BL/6 mice (6-8 weeks old) were randomly divided into Sham, 3.5 GHz RF and 4.9 GHz RF groups, and 8 mice in each group. Mice in the RF groups were systemically exposed to 5G cell phone radiation for consecutive 35 d(1 h/d) with 50 W/m 2 power density. The BBB permeability of mice was detected by Evans Blue (EB) fluorescence experiment. The expression levels of the BBB tight junction-related proteins (ZO-1, occludin and claudin-11) and the gap junction-related protein Connexin 43 were determined by Western blot. Results:The number of spots, fluorescence intensity and comprehensive score of EB were significantly increased in 3.5 GHz RF group and 4.9 GHz RF group compared with the Sham group ( t=12.98, 17.82, P<0.001). Compared with the Sham group, the content of S100B in mouse serum was significantly increased in 3.5 GHz RF group and 4.9 GHz RF group ( t=19.34, 14.68, P<0.001). The BBB permeability was increased in the RF group. The expression level of occludin protein was significantly reduced in the 3.5 GHz RF group ( t=-3.13, P<0.05), and this decrease was much profound in the 4.9 GHz RF group ( t=-6.55, P<0.01). But the protein levels of ZO-1, Claudin-11 and Connexin 43 in the cerebral cortex of the RF groups had no significantly difference in comparison with the Sham group( P>0.05). Conclusions:The continuous exposure of mobile phone RF at 3.5 GHz or 4.9 GHz for 35 d (1 h/d) induces an increase of BBB permeability in the mouse cerebral cortex, perhaps by reducing the expression of occludin protein.

Lumbar spondylolysis is one of the common diseases of low back pain caused by spinal surgery. Its treatment options vary depending on different conditions, from early conservative ones to late surgical ones. There are still disputes over various conservative treatments, choice of surgical methods and the biomechanics of different internal fixation techniques to repair spondylolysis. Therefore, this review summarizes the clinical outcomes of previous clinical treatments of lumbar spondylolysis and the biomechanical characteristics of various techniques to find the mechanical and evidence-based clinical data that may facilitate the treatment of lumbar spondylolysis.

Objective:To investigate the predictors of the efficacy of extracorporeal shock wave lithotripsy (ESWL) in the treatment of ureteral calculi, and to evaluate the predictive value of the maximum ureteral wall thickness (UWT) in the treatment of ureteral calculi with ESWL.Methods:The clinical data of 138 patients with ureteral calculi treated with ESWL in the Second People's Hospital of Hefei from January 2020 to December 2020 were retrospectively analyzed. There were 91 males and 47 females. The age was (50.9±14.8) years old. The body mass index was (25.3±3.6) kg/m 2. The stones of 73 cases were located on the left side and 65 cases were on the right side. 70 cases had upper ureteral stones, 18 cases had middle ureteral stones, and 50 cases had lower ureteral stones. The median length of the stone was 8.5 (7.5, 10.5) mm. The CT value of the stone was 509 (343, 783) HU. The anteroposterior diameter of the renal pelvis was 12.0 (10.1, 16.0) mm, and UWT was (2.8 ± 0.8) mm. All patients underwent urinary non-contrast CT before lithotripsy, and the UWT of the stone bed was measured on the CT images. According to the stone removal situation 2 weeks after the operation, the patients were divided into a successful lithotripsy group and a failed lithotripsy group. Univariate analysis was used to compare the differences of various indicators between the two groups, and multivariate logistic regression was used to analyze the independent predictors of ESWL in the treatment of ureteral calculi for the indicators. The receiver operating characteristic (ROC) curve was used to calculate the area under the curve (AUC) of each independent predictor, and the cut-off value, sensitivity and specificity were analyzed. Results:All operations were successfully completed, and the success rate of the first-stage lithotripsy was 71.7% (99/138). The results of univariate analysis showed that the stone length diameter, stone CT value, anteroposterior diameter of renal pelvis, stone skin distance, and UWT were significantly different between the successful lithotripsy group and the failure group ( P<0.05). There was no significant difference in age, gender, body mass index, stone side and stone location ( P>0.05). The results of multivariate logistic analysis showed that stone length ( OR=1.393, P=0.015), stone CT value ( OR=1.002, P=0.043) and UWT ( OR=17.997, P<0.001) were all for the efficacy of ESWL in the treatment of ureteral stones. The ROC curve was used to compare the three independent predictors. The area under the UWT curve was the largest (AUC=0.898, P<0.001), followed by the length of the stone (AUC=0.744, P<0.001), and the CT value of the stone (AUC=0.672, P= 0.002). The cut-off value for UWT was 3.19 mm, which had a sensitivity of 91.9% and a specificity of 71.8% for predicting the success of ESWL lithotripsy. When dividing the patients into thin wall group (UWT ≤3.19 mm) and thick wall group (UWT>3.19 mm) according to the cut-off value, the success rates of one-stage lithotripsy in the two groups were 89.2% (91 / 102) and 22.2% (8/36), respectively ( P<0.05). Conclusions:UWT, calculus length and calculus CT value are independent predictors of the efficacy of ESWL in the treatment of ureteral calculi, and UWT has the best predictive value. When UWT≤3.19 mm, the success rate of ESWL in the treatment of ureteral calculi is higher.

Objective:To observe and analyze the multimodal imaging characteristics of fundus in patients with sympathetic ophthalmia (SO).Methods:A retrospective study. From October 2012 to December 2021, 28 patients (36 eyes) diagnosed SO in the Department of Ophthalmology, Beijing Tongren Hospital were inclued in the study. There were 19 males (25 eyes) and 9 females (11 eyes), with the mean age of 51.61±12.02 years. There were 8 exciting eyes and 28 sympathizing eyes. The time to onset after trauma or surgery was 46.10±107.98 months. All patients underwent examinations including vision test, color fundus photograph, optical coherence tomography (OCT), fundus fluorescence angiography (FFA), indocyanine green angiography (ICGA). Angio-OCT (OCTA) was performed on 3 eyes and fundus autofluorescence (AF) was performed on 8 eyes. The early and late phase were defined respectively as ≤2 months and >2 months. Their multimodal imaging characteristics were summarized.Results:In 8 exciting eyes, subretinal fibrosis with mutifocal retinal atrophy and pigmentation was noted in 5 eyes (62.50%, 5/8), the other 3 eyes showed sunset glow fundus (37.50%, 3/8). In 28 sympathizing eyes, in the early phase, the fundus photograph showed shallow retinal detachment with optic disc edema in 9 eyes (32.14%, 9/28); in the late phase, peripapillary yellowish-white subretinal lesions in 11 eyes (39.29%, 11/28). In the late course of the disease, there were yellow-white lesions around the optic disc (peridisc) and peripheral subretinal area in 11 eyes (39.29%, 11/28). Dalen-Fuchs nodules were found in 10 eyes (35.71%, 10/28). On OCT, multiple serous retinal detachment and irregular choroidal folds were noted in the early phase; hill-like subretinal hyperreflective elevation was noted in peripapillary area and subfovea with presence of cystic spaces in the intraretina in the late phase. FFA examination showed"pinpoint-like" strong fluorescence in the early stage, and "multi-lake-like" fluorescein accumulation and leakage in the late stage; "map-like" weak fluorescence around the disc in the early stage of the disease, dot-like strong fluorescence lesions in each quadrant of the peripheral retina, and fluorescence in the late stage of the disease course. enhanced. ICGA examination showed that the FFA strong fluorescence lesions in the middle and late stages were weak fluorescence. FAF examination, point-like strong and weak autofluorescence lesions with unclear boundaries. Nine sympathizing eyes with subretinal yellow-white lesions has vision without light-0.1 (significantly decreased vison), while 8 eyes with sunset glow fundus was 0.5-1.0 (mildly decreased vison).Conclusions:SO could not only show the semblable features of acute phases of Vogt-Koyanagi-Harada syndrome, but also the yellowish-white lesions in the peripapillary area, macula and periphery. Most of the eyes with peripapillary lesions has a significantly decreased vison, while the eyes with sunset glow fundus has a mildly decreased vison.

Objective: To  investigate  the  effect  of  X-ray  on  the  polarization  of  mouse  microglia  BV-2  cells. Methods: BV-2 cells at the logarithmic growth stage were randomly divided into the Sham irradiation group and 10 Gy irradiation group. The latter group was given a single X-ray irradiation at a dose of 1.28 Gy/min for 7 min 49 s. The activation rate of BV-2 cells was observed and analyzed under a microscope at 1, 3, 6, 24 h and 48 h after irradiation.The changes of cell morphology were observed by HE staining and immunofluorescence staining; The levels of M1-type activation markers (TNF-α and IL-1β) and M2-type activation marker TGF-β1 in the supernatant of BV-2 cells were detected by ELISA. The levels of polarization-related proteins of M1-type (CD86 and iNOS) and M2-type (CD206) in BV-2 cells were detected by Western blotting. Results　: Morphological results showed that BV-2 cells became larger, and their protrude became coarse and shorter, showing "amoeba" like changes after 10 Gy X-ray irradiation. Compared with the Sham group, the activation rate of BV-2 cells was significantly increased at 3 h, and reached the peak at 6 h, and began to recover at 48 h after irradiation. ELISA results showed an obvious increase in the level of TNF-α and TGF-β1 48 h after irradiation.The level of IL-1β showed a transient decrease at 3～6 h, increased at 24 h, and reached the peak 48 h after irradiation. Western blotting results showed that CD86 protein level did not change significantly at each time points after irradiation, and iNOS protein level in- creased significantly at 1, 6, 24 h and 48 h after irradiation. A fluctuating change in CD206 protein level was found after irradiation. Conclusion　 10 Gy X-ray irradiation can induce the activation of BV-2 cells in vitro, and the polarization type changes with the time after irradiation.