OBJECTIVE: To evaluate the effect of biodegradable magnesium alloy materials in promoting tendon-bone healing during rotator cuff tear repair and to investigate their potential underlying biological mechanisms. METHODS: Forty-eight 8-week-old Sprague Dawley rats were taken and randomly divided into groups A, B, and C. Rotator cuff tear models were created and repaired using magnesium alloy sutures in group A and Vicryl Plus 4-0 absorbable sutures in group B, while only subcutaneous incisions and sutures were performed in group C. Organ samples of groups A and B were taken for HE staining at 1 and 2 weeks after operation to evaluate the safety of magnesium alloy, and specimens from the supraspinatus tendon and proximal humerus were harvested at 2, 4, 8, and 12 weeks after operation. The specimens were observed macroscopically at 4 and 12 weeks after operation. Biomechanical tests were performed at 4, 8, and 12 weeks to test the ultimate load and stiffness of the healing sites in groups A and B. At 2, 4, and 12 weeks, the specimens were subjected to the following tests: Micro-CT to evaluate the formation of bone tunnels in groups A and B, HE staining and Masson staining to observe the regeneration of fibrocartilage at the tendon-bone interface after decalcification and sectioning, and Goldner trichrome staining to evaluate the calcification. Immunohistochemical staining was performed to detect the expressions of angiogenic factors, including vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2), as well as osteogenic factors at the tendon-bone interface. Additionally, immunofluorescence staining was used to examine the expressions of Arginase 1 and Integrin beta-2 to assess M1 and M2 macrophage polarization at the tendon-bone interface. The role of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway in tendon-bone healing was further analyzed using real-time fluorescence quantitative PCR. RESULTS: Analysis of visceral sections revealed that magnesium ions released during the degradation of magnesium alloys did not cause significant toxic effects on organs such as the heart, liver, spleen, lungs, and kidneys, indicating good biosafety. Histological analysis further demonstrated that fibrocartilage regeneration at the tendon-bone interface in group A occurred earlier, and the amount of fibrocartilage was significantly greater compared to group B, suggesting a positive effect of magnesium alloy material on tendon-bone interface repair. Additionally, Micro-CT analysis results revealed that bone tunnel formation occurred more rapidly in group A compared to group B, further supporting the beneficial effect of magnesium alloy on bone healing. Biomechanical testing showed that the ultimate load in group A was consistently higher than in group B, and the stiffness of group A was also greater than that of group B at 4 weeks, indicating stronger tissue-carrying capacity following tendon-bone interface repair and highlighting the potential of magnesium alloy in enhancing tendon-bone healing. Immunohistochemical staining results indicated that the expressions of VEGF and BMP-2 were significantly upregulated during the early stages of healing, suggesting that magnesium alloy effectively promoted angiogenesis and bone formation, thereby accelerating the tendon-bone healing process. Immunofluorescence staining further revealed that magnesium ions exerted significant anti-inflammatory effects by regulating macrophage polarization, promoting their shift toward the M2 phenotype. Real-time fluorescence quantitative PCR results demonstrated that magnesium ions could facilitate tendon-bone healing by modulating the PI3K/AKT signaling pathway. CONCLUSION Biodegradable magnesium alloy material accelerated fibrocartilage regeneration and calcification at the tendon-bone interface in rat rotator cuff tear repair by regulating the PI3K/AKT signaling pathway, thereby significantly enhancing tendon-bone healing.
Animals ; Rotator Cuff Injuries/metabolism* ; Rats, Sprague-Dawley ; Signal Transduction ; Wound Healing/drug effects* ; Alloys/pharmacology* ; Rats ; Proto-Oncogene Proteins c-akt/metabolism* ; Rotator Cuff/metabolism* ; Macrophages/metabolism* ; Magnesium/pharmacology* ; Phosphatidylinositol 3-Kinases/metabolism* ; Vascular Endothelial Growth Factor A/metabolism* ; Male ; Biocompatible Materials ; Bone Morphogenetic Protein 2/metabolism*

Objective:To understand the level of radiation doses from digital mammography in Tianjin and the associated influencing factors.Methods:The stratified quota sampling method was used for analysis of 374 digital mammography-examined individuals by using 12 digital mammography devices in 12 selected medical institutions. The examinations were carried out in terms of exposure positions[(craniocaudal (CC) and mediolateral oblique (MLO)], compressed breast thickness, tube voltage, time product of tube current (mAs) and target/filter.Results:The median age of the examined individuals in this survey was 43 years, the median tube voltage (kV) was 29 kV, the median tube current time product was 60.3 mAs, the median compressed breast thickness was 48 mm, and the median average glandular dose (AGD) was 1.32 mGy. The mean dose to the analyzed glandular tissue in the conditions of different target/filters varies in the descent order of Mo/Mo > Mo/Rh > Rh/Rh > W/Rh > W/Al, with the difference being statistically significant difference ( χ2=885.90, P<0.05). The mean dose to the glandular tissue increased with the increase in compressed breast thickness, and the difference was statistically significant ( χ2=31.58, 8.56, 76.13, 118.47, 24.09, P<0.05). Conclusions:The median average glandular dose in Tianjin was 1.32 mGy. This level is lower than in Guangxi province and Fuzhou city, similar to that in Beijing and Guangdong province, and lower than the national survey result of average breast dose. The efforts should be dedicated to further strengthening the research on the related factors of the average glandular dose in order to protect the health and safety of the examined individuals.

Objective:To study the level of CT dose to paediatric patients in Tianjin, and to provide basic data for establishing the diagnostic reference levels for paediatric patients from CT examinations in Tianjin.Methods:In 2022, a general survey was carried out of the CT doses to the head, chest, abdomen and pelvis of the scanned paediatric patients in two tertiary pediatric hospitals and seven tertiary general hospitals in Tianjin. The scanned pediatric patients were divided into four age groups in terms of the age of -1, -5, -10 and -15 years, and 20 patients were investigated in each age group in each hospital. The basic information were collected on the scanned patients, CT scanning parameters, volume CT dose index (CTDI vol), dose length product (DLP), and the differences in CTDI vol and DLP on the same site among different age groups and different types of hospitals were analyzed. Results:There were significant differences in CTDI vol and DLP between different age groups at the same site (head, chest, abdominal and pelvic, CTDI vol:χ2=296.51, 193.82, 291.72, P<0.001; DLP: χ2=291.22, 263.63, 344.97, P<0.001). There were significant differences in CTDI vol and DLP among different types of hospitals on the same site (head, chest, abdominal and pelvic, CTDI vol:Z=-13.13, -7.57, -15.27, P<0.001; DLP: Z=-9.07, -6.15, -11.57, P < 0.001). Conclusions:The 75 th percentile values of CTDI vol and DLP for pediatric head, chest, abdomen and pelvis CT scanning in tertiary hospitals in Tianjin are at a good level, and the dose on some examination sites are relatively high. Further optimization of pediatric CT scanning procedures is necessary.

Objective:To explore the clinical features of ultrasound intervention combined with antibiotics in the treatment of Klebsiella pneumoniae liver abscess, and to provide a reference for clinical treatment.Methods:The clinical data of 100 patients with Klebsiella pneumoniae liver abscess treated in Beijing Friendship Hospital Affiliated to Capital Medical University from January 2015 to November 2020 were analyzed retrospectively. The patient's gender, age, abscess diameter, number of abscesses, abscess separation, air cavity formation and length of hospital stay were recorded. The blood white blood cell (WBC), neutrophil percentage (GR%), platelet count (PLT), C-reactive protein (CRP), procalcitonin (PCT), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), prothrombin activity (PTA) before and after treatment were analyzed.Results:After treatment, the infection indexes (WBC, GR%, PLT, CRP, PCT) were significantly decreased, and the liver function indexes (ALT, AST, TBIL, PTA) were significantly improved ( P<0.05). Patients were divided into two groups according to diabetes. The results showed that the diabetic group was prone to air cavity formation (χ 2=8.632, P=0.003), and there was no significant difference between other clinical indicators among the groups ( P>0.05). Diabetes mellitus group was divided into two groups based on hemoglobin A1c (HbA1c) 9%. The results showed that the HbA1c>9% group was younger ( t=2.861, P=0.006), more male (χ 2=6.81, P=0.013), and more prone to form multiple abscesses (χ 2=10.304, P=0.001), while the other clinical indicators were not statistically significant. Conclusions:Ultrasound intervention combined with antibiotics can effectively treat liver abscess. Patients with diabetes are prone to air cavity formation, which should be paid more attention in clinic.

Objective: To investigate the safety and efficacy of irreversible electroporation (IRE) hepatic ablation with high-frequency bipolar pulse in swine. Methods: The experimental study was conducted. A total of 18 swines of either gender, aged (6.8+ 0.8)months with a range of 5.5-8.0 months, were collected from Animal Laboratory Center of Army Medical University. were randomly divided into 15 in experimental group and 3 in control group. The swines in experimental group underwent IRE hepatic ablation with high-frequency bipolar pulse, and 3 swines were chose randomly and underwent enhanced CT examination immediately after ablation, and at 3, 7, 14, and 28 days after ablation. The liver tissues were taken for histopathological examination. The swines in the control group underwent IRE hepatic ablation with high-frequency monopolar burst, and was performed enhanced CT examination at 3 days after ablation. Liver tissues were taken for histopathological examination. Observation indicators: (1) comparison of muscle contraction of siwnes between two groups; (2) imaging performance on enhanced CT after IRE ablation in the experimental group; (3) hepatic histopathological findings after IRE ablation in the experimental group; (4) comparison of apoptotic index in the ablation zone between two groups. The measurement data with normal distribution were expressed as Mean±SD, and comparison between groups was performed by the independent sample t test. Results: (1) Comparison of muscle contraction between two groups: swines in both groups underwent ablation successfully. The degree of muscle contraction was (9.8±0.4)m/s² and (48.6±0.5)m/s² in the experimental group and in the control group, respectively, showing statistically significant difference between the two groups (t=-163.50, P<0.05). (2) Imaging performance on enhanced CT after IRE ablation in the experimental group: the enhanced CT examination of swines immediately after IRE ablation showed a low-density shadow and clear boundary in the ablation zone. There was no obvious abnormality in the ablation zone and its adjacent large vessels. No serious complications occurred after the ablation. The boundary between the ablation zone and the normal liver tissue of the experimental group gradually became blurred over time, and the ablation zone was gradually replaced by normal liver tissue. The ablation zone at the 28 days after ablation was significantly reduced or even disappeared on imaging of enhanced CT examination.The maximum diameter of the ablation zone was (1.81±0.17)cm immediately after ablation, (1.75±0.19)cm at the 3 days after ablation, (1.32±0.22)cm at the 7 days after ablation, (0.65±0.14)cm at the 14 days after ablation, (0.28±0.10)cm at the 28 days after ablation, respectively. (3) Hepatic histopathological findings after IRE ablation in the experimental group: the HE staining of ablated tissue immediately after ablation showed that the cells in the ablation zone were swollen, arranged disorderly, and bleeding was observed around some of the needles.The bile ducts and blood vessels were intact in the ablation zone, and a large number of deeply stained nuclei were seen at 3 days after ablation, some of the nucleus and apoptotic bodies were partially dissolved or cleaved. A large number of inflammatory cell were infiltrated around the ablation zone. Intact vascular and biliary endothelial cells were observed by von Willebrand factor staining, a larger number of apoptotic cells with deeply stained nuclei in the ablation zone were observed by terminal-deoxynucleoitidyl transferase mediated nick end labeling staining, and partial deposited dark brown calcium salt was seen by Von Kossa staining. More newborn hepatocytes were observed growing from the periphery of the ablation zone to the center at the 7, 14, 28 days after ablation. Smooth muscle cell proliferation was observed at 14 and 28 days after ablation. The ablation zone was replaced by new cells on 28 days after ablation. (4) Comparison of apoptotic index in the ablation zone between two groups: the apoptotic index of the ablation zone was significantly higher in the experimental group than in the control group on the 3 days after operation (76.67%±0.04% vs. 64.03%±0.05%, t=4.79, P<0.05). Conclusion IRE hepatic ablation of swine using high-frequency bipolar pulse is safe and reliable, and it has more apoptotic cells than IRE ablation with high-frequency monopolar burst.

Objective: To investigate the usage frequency of radiological diagnosis devices in ten hospitals in Tianjin, China, and to provide a basis for the survey of medical radiation frequency in Tianjin. Methods: Ten hospitals from the ten districts in Tianjin were enrolled as subjects by a convenient sampling method. A survey was conducted to assess the general information and radiological diagnosis device information and usage frequency in those hospitals in 2016. The radiological examination frequency in Tianjin was estimated. Results: A total of 610 458 patients received radiological examinations in the sampled hospitals in 2016. In those patients, 371 882 received X-ray examinations for imaging and 238 576 for computed tomography (CT) ; there were slightly more female patients than male patients, suggesting a relatively equal gender distribution; patients older than 40 years accounted for 65.53%, which was the highest among all the age groups. Different types of radiological diagnosis devices were mostly used in tertiary and secondary hospitals. In Tianjin, the estimated frequency of X-ray examination for imaging and CT scanning was 451 and 188 per thousand people, respectively, in 2016. Conclusion The frequency of radiological diagnosis is relatively high in the ten hospitals in Tianjin. The investigation of medical radiation in Tianjin needs to be improved.

Background Excessive elongation of axis and expansion of sclera is one of the hot topics in the study of the pathogenesis of high myopia.To establish a human scleral fibroblasts (HSFs)-collagen matrix culture model is helpful for understanding the reciprocal and adaptive interactions between HSFs and the collagen matrix in tissue.Objective The aim of this study was to establish a HSFs-seeded collagen three-dimension culture system that may mimic the sclera remolding in myopia.Methods HSFs were isolated and cultured from donor eyes by explant culture and purified by passages culture in vitro.The expressions of vimentin and keratin in the cells were detected by immunofluorescence technique to identify the cells.Rat tail tendon was obtained from 8-week-old SPF SD rats to prepare the collagen matrix.The mixed solution of 400 μl collagen matrix and 1 100 μl PBS,200 μ1 nutrient medium,50 μ1 NaOH and HSF suspension were mixed to prepare the collagen gel three-demension culture system.The growth and morphology of the cells in the culture system were observed under the inverted phase contrast microscope,and IPP-5 software was used to measure the contraction area of collagen gel,and the mechanical creep properties of the HSFs-seeded collagen matrix were measured by a biomechanics test instrument.Results HSFs emigrated from tissue 7 days after culture and passage could be performed 14 days after culture.The expression of keratin was absent in HSFs,while vimentin was positively expressed.The free-cell collagen gel was clear and unchanged in the experimental duration.However,the cells were obviously increased on the three-demension culture system and showed a tissue-like structure of net-like arrangement on dozens of layers.In 7-14 days after culture,the collagen gel area in a three-demension collagen matrix revealed a decrease of 90％.Duotriode-like and fusiform cells were seen 24 hours after culture.The biomechanical creep curve of HSFs-seeded collagen matrix consisted of the nonlinear section (0-100 seconds) and linear section (100-600 seconds),and the former appeared to be an elastic change of the gel under the temporal stress,and the latter was the creeping of the gel with the time.Conclusions Rat tail collagen appears to have a good biocompatibility to HSFs.HSFs-seeded collagen matrix can retain the mechanical creep properties,and it may be a good tool for the study on the relationship between HSFs and extracellular matrix or intercellular biological behaviour for scleral remodeling.

Objective To study the impact of respiratory frequency and amplitude of patients with the thoracic or abdomen tumor on 4DCT' s reconstructed image.Methods 75 thoracic or abdomen tumor patients who performed a scanning with belly belt-type respiratory gating on 4DCT between November 2012 to March 2013 in our hospital were retrieved.Reviewed their respiratory frequency,amplitude and fault distance of 4DCT' s reconstructed image and analyzed the correlation fault distance of the reconstructed image.The correlation analysis was used by bivariate Spearman method.Results Among these reconstructed images,fault distance more than 6 mm could be seen in 11 cases,fault distance ranging from 3 mm to 6 mm could be found in 46 cases,and distance less than 3 mm could be detected in 18 case.Respiratory frequency correlated significantly with the amplitude (rs =0.369,P =0.000);the respiratory rate had a tight association with the fault distance of the reconstructed image (r,=0.273,P=0.018);and respiratory amplitude was associated obviously with the fault distance of the reconstructed image (r,=0.696,P=0.000).Conclusions Both 4DCT reconstructed image and respiratory amplitude are significantly correlated to the continuity of the respiratory frequency.The smaller the respiratory frequence and amplitude change are,the better continuity will be.

Objective To study the impact of setup error caused by computed tomography ( CT) images with different resolutions in the Sentinel system on clinical treatment. Methods A phantom was scanned by large?aperture positioning CT with two different resolutions ( CT1:0. 5 mm × 0. 5 mm × 1. 0 mm, FOV 256 mm, Matrix 512, thickness 1 mm;CT3:1. 0 mm×1. 0 mm×3. 0 mm, FOV 500 mm, Matrix 512, thickness 3 mm) . The CT images were transferred to the planning system. The radiation fields were designed and transferred to MOSAIQ and Sentinel systems. Ten fixed setup errors were applied to a six degree of freedom couch. The Sentinel system was used to position the two groups of CT images and generate the setup errors. The comparison of two datasets was made by paired t?test. Cone?beam CT was used for independent verification. Results The setup errors in x?, y?, and z?directions were significantly smaller on CT1 than on CT3(0.19±0. 11 vs. 0.33±0. 16 mm, P=0. 061;0.59±0. 79 vs. 1.07±1. 09 mm, P=0. 008;0.67±0. 75 vs. 1.16±1. 30 mm, P=0. 043). There were no significant differences in rotational errors in x?, y?, or z?directions between the two datasets ( P=0. 494;P=0. 182;P=0. 298) . Conclusions The Sentinel system has a higher setup accuracy in the 0. 5 mm×0. 5 mm×1. 0 mm mode than in the 1. 0 mm×1. 0 mm×3. 0 mm mode. However, the later mode is still an acceptable choice in clinical treatment.