1.Effect of vitamin B12 eye drops on the expression of MMP-9 and TNF-α in the cornea of mice with dry eye disease
Hui DONG ; Huacheng ZHENG ; Weiting WANG ; Haixia ZHAO
Acta Universitatis Medicinalis Anhui 2026;61(3):424-431
ObjectiveTo investigate how vitamin B12 eye drops regulate MMP-9 and TNF-α expression levels in the corneas of dry eye disease (DED) mouse model induced by a combination of an artificially simulated dry environment (air humidity 30%) and subcutaneous injection of hyoscine hydrobromide. MethodsFifty C57BL/6 female mice were used in the study. 10 mice formed A group (blank control), while the remaining 40 mice were subjected to dry eye disease induction through subcutaneous injection of scopolamine hydrobromide in a controlled environment with 30% air humidity. All mice underwent schirmer I test (SIT), tear break-up time (TBUT), and corneal fluorescence staining score(CFS)evaluations. Mice meeting modeling criteria were randomly assigned to three groups: B group (model group), C group (PBS control), and D group (vitamin B12 group). 0, 7, 14, and 21 days after treatment, each group received TBUT, SIT, CFS, and corneal inflammation assessments. Macroscopic analysis evaluated the efficacy of vitamin B12 eye drops in treating dry eye. After 21 days of treatment, all mice were euthanized via cervical dislocation and their corneas analyzed using HE staining to examine morphological changes. ELISA and immunohistochemical methods were employed to detect MMP-9 and TNF-α expression levels in corneal tissues across groups. ResultsIn dry environments (air humidity 30%), subcutaneous injection of scopolamine hydrobromide induced changes in dry eye-related indicators in mice: SIT significantly decreased, TBUT significantly shortened, corneal fluorescein staining increased, and CFS all significantly elevated (P 0.05), indicating successful establishment of the dry eye model. A total of 30 dry eye mice were enrolled. When the dry eye model was successfully established without drug intervention, no statistically significant differences were observed between B group, C group and D group in terms of TBUT, SIT, corneal fluorescein staining, or CFS. Compared with A group, B group, C group and D group showed statistically significant differences in reduced SIT, shortened TBUT, increased corneal fluorescein staining, and elevated CFS (P 0.05). After drug intervention, D group (vitamin B12 group) exhibited significantly increased SIT, prolonged TBUT, reduced corneal fluorescein staining, clearer corneas, decreased fluorescein staining, and lower CFS compared with B and C groups(P 0.05). ELISA and immunohistochemical staining results showed that compared with A group, B and C groups exhibited significantly increased expression of MMP-9 and TNF-α in corneal tissues (P 0.05). D group showed decreased expression of MMP-9 and TNF-α compared with B and C groups but remained higher than A group (P 0.05). ConclusionThe expression of MMP-9 and TNF-α in the corneal tissues of mice with dry eye is elevated, suggesting that both inflammatory factors, MMP-9 and TNF-α, are involved in the development of dry eye. Vitamin B12 eye drops may improve the symptoms of ocular surface discomfort by promoting the repair of the corneal epithelium. Vitamin B12 eye drops may increase tear secretion, prolong tear film break up time, reduce corneal fluorescein staining, and alleviate the inflammatory reaction of the cornea by decreasing the expression of MMP-9 and TNF-α in the corneal tissues of the mice, thus playing a therapeutic role in the treatment of dry eye disease.
2.Differences in deltamethrin resistance and kdr gene mutation in Culex tritaeniorhynchus population in and outside the Yellow Sea wetland
Xiao-er ZHANG ; Zhi-ming WU ; Ye TIAN ; Qian CUI ; Yu-qian JI ; Huan WANG ; Shu-juan YANG ; Yi-chao ZHAO ; Yu WANG ; Hua-yu YIN ; Yu DING ; Guo-jin YAN ; Min-sen ZHAO ; Shou-gang ZHANG ; Bing-dong SONG ; Hong-na CHEN ; Jian GAO ; Wei-fang YANG ; Yu-fu ZHANG ; Hui LIU ; Hong-liang CHU
Acta Parasitologica et Medica Entomologica Sinica 2026;33(2):101-107
Objective To gain insights into the biological characteristics of different populations of Culex tritaeniorhynchus within and around the Yellow Sea wetland from the perspective of the occurrence of resistance, we investigated the levels of resistance to deltamethrin and kdr gene mutation in the wetland and its peripheral areas. Methods Specimens were collected from Cx. tritaeniorhynchus populations at two monitoring sites in the Rare Bird National Nature Reserve and Tiaozi Ni Wetland Scenic Area, and also from two populations in Yancheng City and the Liuhe District of Nanjing, and the resistance of these mosquitoes to deltamethrin was determined using the CDC biotest bottle method. For each concentration of deltamethrin assessed, a random subset of exposed specimens was selected for amplification of the kdr gene fragment, followed by Sanger sequencing to identify and analyze resistance-associated mutations. Results The LC50 levels of deltamethrin among mosquitoes from the four populations in Luhe, Yancheng, the Rare Bird National Nature Reserve and the Tiaozi Ni Wetland Scenic Area were 2.048 5, 7.798 2, 3.473 3, and 17.695 5 mg/mL, respectively, with corresponding concentrations of deltamethrin ranging from 0.005 to 5.000,0.050 to 50.000,0.050 to 25.000 and 0.050 to 50.000 mg/mL, respectively. Furthermore, the ranges of the KT50 values were 11.76-107.43, 67.05-216.30,29.77-107.43 and 28.40-329.51 min; the 1-h knockdown rates were 34.58%-99.15%, 9.52%-43.80%, 55.09%-73.01%, and 10.09%-68.07%; and the 24-h mortality rates were 12.15%-67.52%,9.52%-79.56%,13.17%-82.21%, and 11.01%-78.99%, respectively. With respect to kdr gene mutation, we assayed a total of 63,70,59, and 57 mosquitoes for the four populations, for which we detected L1014F mutation frequencies of 14.29%, 35.00%, 20.34%, and 31.58%, respectively, with a majority of these mutations being heterozygous for resistance. In addition, five adult mosquitoes were identified has having synonymous mutations at site 1011[i. e. , AAT(asparagine)mutation to AAC(asparagine)]. Conclusions Our findings revealed the clear resistance of Cx. tritaeniorhynchus to deltamethrin in the Yancheng region of the Yellow Sea wetland, and the resistance phenotype and kdr frequency of Cx. tritaeniorhynchus in the wetland environment were comparable to those of Cx. tritaeniorhynchus in the wetland environment, thereby indicating that the resistance of different populations of Cx. tritaeniorhynchus was homogeneous under the pressure of different insecticide selection within and around the wetland. However, the underlying mechanisms need to be further studied.
3.Whole-liver intensity-modulated radiation therapy as a rescue therapy for acute graft-versus-host disease after liver transplantation.
Dong CHEN ; Yuanyuan ZHAO ; Guangyuan HU ; Bo YANG ; Limin ZHANG ; Zipei WANG ; Hui GUO ; Qianyong ZHAO ; Lai WEI ; Zhishui CHEN
Chinese Medical Journal 2025;138(1):105-107
4.Development of core outcome set for traditional Chinese medicine interventions in diabetic peripheral neuropathy.
Lu-Jie WANG ; Liang-Zhen YOU ; Chang CHANG ; Yu-Meng GENG ; Jin-Dong ZHAO ; Zhao-Hui FANG ; Ai-Juan JIANG
China Journal of Chinese Materia Medica 2025;50(14):4071-4080
This study developed a core outcome set(COS) for traditional Chinese medicine(TCM) interventions in diabetic peripheral neuropathy(DPN), standardizing evaluation metrics for TCM efficacy and providing a new framework for DPN treatment and management. A systematic search was conducted across databases, including CNKI, Wanfang, and PubMed, targeting clinical trial literature published between January 1, 2013, and January 1, 2023. The search focused on extracting outcome indicators and measurement tools used in TCM treatments for DPN. Retrospective data collection was performed from January 2018 to June 2023, involving 200 DPN patients hospitalized at the Department of Endocrinology of the First Affiliated Hospital of Anhui University of Chinese Medicine. Additionally, semi-structured interviews were conducted with inpatients, outpatients, their families, and nursing staff to further refine and enhance the list of outcome indicators. After two rounds of Delphi questionnaire survey and consensus meeting, a consensus was reached. The study initially retrieved 3 421 publications, of which 170 met the inclusion criteria after review. These publications, combined with retrospective analysis and semi-structured interviews, supplemented the list of indicators. After two rounds of Delphi surveys, experts agreed on 24 indicators and 6 measurement tools. The final COS determined by expert consensus meeting included 5 domains and 13 outcome indicators: neurological function signs, quality of life, TCM syndrome score, nerve conduction velocity, current perception threshold test, fasting blood glucose, 2 h postprandial blood glucose, glycated hemoglobin, complete blood count, urinalysis, liver function test, kidney function test, and electrocardiogram.
Humans
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Diabetic Neuropathies/drug therapy*
;
Medicine, Chinese Traditional/methods*
;
Drugs, Chinese Herbal/therapeutic use*
;
Retrospective Studies
;
Treatment Outcome
;
Male
;
Female
5.Mechanism of puerarin improving myocardial contractile function in myocardial hypertrophy by inhibiting ferroptosis via Nrf2/ARE/HO-1 signaling pathway.
Yan-Dong LIU ; Wei QIAO ; Zhao-Hui PEI ; Guo-Liang SONG ; Wei JIN ; Wei-Bing ZHONG ; Qin-Qin DENG
China Journal of Chinese Materia Medica 2025;50(16):4679-4689
This study aims to explore the specific mechanism by which puerarin inhibits ferroptosis and improves the myocardial contractile function in myocardial hypertrophy through the nuclear factor erythroid 2-related factor 2(Nrf2)/antioxidant response element(ARE)/heme oxygenase-1(HO-1) signaling pathway. The hypertrophic cardiomyocyte model was established using phenylephrine, and H9c2 cells were divided into control group, model group, puerarin group, and puerarin+ML385 group. Cell viability and surface area were detected by cell counting kit-8(CCK-8) and immunofluorescence experiments. The mitochondrial membrane potential and Ca~(2+) concentration were measured. The ferroptosis-related indicators were detected by biochemical and fluorescence staining methods. The expression of proteins related to ferroptosis and the Nrf2/ARE/HO-1 signaling pathway was detected by Western blot. A myocardial hypertrophy model was established, and 40 rats were randomly divided into sham group, model group, puerarin group, and puerarin+Nrf2 inhibitor(ML385) group, with 10 rats in each group. Echocardiogram, hemodynamic parameters, and myocardial hypertrophy parameters were measured. Histopathological changes of myocardial tissues were observed by hematoxylin and eosin(HE) staining and Masson staining. Biochemical methods, enzyme-linked immunosorbent assay(ELISA), and fluorescence staining were used to detect inflammatory factors and ferroptosis-related indicators. Immunohistochemistry was used to detect the expression of proteins related to ferroptosis and the Nrf2/ARE/HO-1 signaling pathway. Cell experiments showed that puerarin intervention significantly enhanced the viability of hypertrophic cardiomyocytes, reduced their surface area, and restored mitochondrial membrane potential and Ca~(2+) homeostasis. Mechanism studies revealed that puerarin promoted Nrf2 nuclear translocation, upregulated the expression of HO-1, solute carrier family 7 member 11(SLC7A11), and glutathione peroxidase 4(GPX4), and decreased malondialdehyde(MDA), reactive oxygen species(ROS), and iron levels. These protective effects were reversed by ML385. In animal experiments, puerarin improved cardiac function in rats with myocardial hypertrophy, alleviated myocardial hypertrophy and fibrosis, inhibited inflammatory responses and ferroptosis, and promoted nuclear Nrf2 translocation and HO-1 expression. However, combined intervention with ML385 led to deterioration of hemodynamics and a rebound in ferroptosis marker levels. In conclusion, puerarin may inhibit cardiomyocyte ferroptosis through the Nrf2/ARE/HO-1 signaling pathway, thereby improving myocardial contractile function in myocardial hypertrophy.
Animals
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NF-E2-Related Factor 2/genetics*
;
Rats
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Ferroptosis/drug effects*
;
Signal Transduction/drug effects*
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Isoflavones/pharmacology*
;
Male
;
Rats, Sprague-Dawley
;
Cardiomegaly/genetics*
;
Myocytes, Cardiac/metabolism*
;
Antioxidant Response Elements/drug effects*
;
Myocardial Contraction/drug effects*
;
Heme Oxygenase-1/genetics*
;
Cell Line
6.Biomechanical study and clinical application of two osteotomy guide methods in media open wedge high tibial osteotomy operation.
Chao QI ; Xiao-Ming LI ; Dong-Hui GUO ; Qiu-Ling SHI ; Yun-Chao ZHAO ; Jun DONG ; Zheng-Xin MENG ; Xing-Yue WANG
China Journal of Orthopaedics and Traumatology 2025;38(7):698-704
OBJECTIVE:
To explore the effectiveness and feasibility of two osteotomy guides in medial open wedge high tibial osteotomy (MOWHTO).
METHODS:
Clinical data of 103 patients who underwent routine MOWHTO surgery between January 2020 and December 2022 were collected for retrospective analysis. The patients were divided into two groups based on the method of osteotomy guide plate. The control group of 51 patients received traditional osteotomy guide plate technique, including 17 males and 34 females, aged from 48 to 68 years old with an average of(57.93±4.82) years old, with a disease duration ranged from 1 to 8 years with an average of (4.89±1.49) years. The observation group of 52 patients received personalized osteotomy guide plate technique, including 23 males and 29 females, aged from 48 to 69 with an average of (58.22±5.10) years, with a disease duration ranged from 1 to 9 years with an average of(5.10±1.55) years. The perioperative indicators, complications, and knee joint recovery rate were statistically analyzed for both groups, as well as the preoperative and postoperative coagulation function, fibrinogen (FIB), D-dimer (D-D), gait parameters (step frequency, step length, step speed), biomechanical indicators, weight bearing line (WBL), medial proximal tibial angle (MPTA), joint line conergence angle (JLCA), and anterior cruciate ligament (ACL) function (body width, tibial anterior displacement).
RESULTS:
All patients were followed up for 6 months. The intraoperative blood loss, operation time, and number of fluoroscopic views in the observation group were (358.58±93.76) ml, (84.42±8.17) min, and (2.00±0.44) times, respectively, which were all less than those in the control group (465.55±105.38) ml, (96.53±10.51) min, and (6.31±0.58) times (P<0.05). Three days after surgery, the FIB and D-D levels in the observation group were (4.21±0.48) g·L-1 and (204.47±35.59) μg·L-1, respectively, which were both lower than those in the control group (5.56±0.57) g·L-1 and (311.12±42.23) μg·L-1 (P<0.05). Three months after surgery, the step frequency, step length, and step speed in the observation group were (1.89±0.23) steps·s-1, (0.57±0.15) m, and (0.99±0.11) m·s-1, respectively, which were all higher than those in the control group (1.80±0.18) steps·s-1, (0.50±0.14) m, and (0.95±0.09) m·s-1 (P<0.05). Three months after surgery, the WBL and MPTA in the observation group were (45.53±4.41)% and (87.03±8.15)°, respectively, which were both higher than those in the control group (38.38±4.36)% and (83.68±8.50)°, and the JLCA was (2.36±0.24)°, which was lower than that in the control group (2.61±0.33)° (P<0.05). The ACL body width during internal fixation removal was (5.60±0.51) mm, which was greater than that in the control group (5.08±0.56) mm, and the tibial migration was (5.70±0.42) mm, which was less than that in the control group (6.33±0.48) mm (P<0.05). There was no significant difference in the incidence of complications between the two groups (P>0.05). Six months after surgery, there was no significant difference in the recovery rate of knee joint between the two groups (P>0.05).
CONCLUSION
The application of personalized osteotomy guide technique in MOWHTO can help improve knee biomechanics and ACL function, and has less effect on coagulation function and no increase in complications.
Humans
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Male
;
Female
;
Osteotomy/methods*
;
Middle Aged
;
Tibia/physiopathology*
;
Aged
;
Biomechanical Phenomena
;
Retrospective Studies
;
Osteoarthritis, Knee/physiopathology*
7.Protective effect of sub-hypothermic mechanical perfusion combined with membrane lung oxygenation on a yorkshire model of brain injury after traumatic blood loss.
Xiang-Yu SONG ; Yang-Hui DONG ; Zhi-Bo JIA ; Lei-Jia CHEN ; Meng-Yi CUI ; Yan-Jun GUAN ; Bo-Yao YANG ; Si-Ce WANG ; Sheng-Feng CHEN ; Peng-Kai LI ; Heng CHEN ; Hao-Chen ZUO ; Zhan-Cheng YANG ; Wen-Jing XU ; Ya-Qun ZHAO ; Jiang PENG
Chinese Journal of Traumatology 2025;28(6):469-476
PURPOSE:
To investigate the protective effect of sub-hypothermic mechanical perfusion combined with membrane lung oxygenation on ischemic hypoxic injury of yorkshire brain tissue caused by traumatic blood loss.
METHODS:
This article performed a random controlled trial. Brain tissue of 7 yorkshire was selected and divided into the sub-low temperature anterograde machine perfusion group (n = 4) and the blank control group (n = 3) using the random number table method. A yorkshire model of brain tissue injury induced by traumatic blood loss was established. Firstly, the perfusion temperature and blood oxygen saturation were monitored in real-time during the perfusion process. The number of red blood cells, hemoglobin content, NA+, K+, and Ca2+ ions concentrations and pH of the perfusate were detected. Following perfusion, we specifically examined the parietal lobe to assess its water content. The prefrontal cortex and hippocampus were then dissected for histological evaluation, allowing us to investigate potential regional differences in tissue injury. The blank control group was sampled directly before perfusion. All statistical analyses and graphs were performed using GraphPad Prism 8.0 Student t-test. All tests were two-sided, and p value of less than 0.05 was considered to indicate statistical significance.
RESULTS:
The contents of red blood cells and hemoglobin during perfusion were maintained at normal levels but more red blood cells were destroyed 3 h after the perfusion. The blood oxygen saturation of the perfusion group was maintained at 95% - 98%. NA+ and K+ concentrations were normal most of the time during perfusion but increased significantly at about 4 h. The Ca2+ concentration remained within the normal range at each period. Glucose levels were slightly higher than the baseline level. The pH of the perfusion solution was slightly lower at the beginning of perfusion, and then gradually increased to the normal level. The water content of brain tissue in the sub-low and docile perfusion group was 78.95% ± 0.39%, which was significantly higher than that in the control group (75.27% ± 0.55%, t = 10.49, p < 0.001), and the difference was statistically significant. Compared with the blank control group, the structure and morphology of pyramidal neurons in the prefrontal cortex and CA1 region of the hippocampal gyrus were similar, and their integrity was better. The structural integrity of granulosa neurons was destroyed and cell edema increased in the perfusion group compared with the blank control group. Immunofluorescence staining for glail fibrillary acidic protein and Iba1, markers of glial cells, revealed well-preserved cell structures in the perfusion group. While there were indications of abnormal cellular activity, the analysis showed no significant difference in axon thickness or integrity compared to the 1-h blank control group.
CONCLUSIONS
Mild hypothermic machine perfusion can improve ischemia and hypoxia injury of yorkshire brain tissue caused by traumatic blood loss and delay the necrosis and apoptosis of yorkshire brain tissue by continuous oxygen supply, maintaining ion homeostasis and reducing tissue metabolism level.
Animals
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Perfusion/methods*
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Disease Models, Animal
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Brain Injuries/etiology*
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Swine
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Male
;
Hypothermia, Induced/methods*
8.Clinical and genetic characteristics of congenital adrenal hyperplasia: a retrospective analysis.
Cai-Jun WANG ; Ya-Wei ZHANG ; Da-Peng LIU ; Juan JIN ; Zhao-Hui LI ; Jing GUO ; Yao-Dong ZHANG ; Hai-Hua YANG ; Wen-Qing KANG
Chinese Journal of Contemporary Pediatrics 2025;27(11):1367-1372
OBJECTIVES:
To study the clinical and genetic characteristics of children with congenital adrenal hyperplasia (CAH).
METHODS:
Clinical data, laboratory findings, and genetic test results of 63 children diagnosed with CAH at Henan Children's Hospital from January 2017 to December 2024 were retrospectively reviewed.
RESULTS:
Of the 63 patients, the mean age at the first visit was (21 ± 14) days; 29 (46%) were of male sex and 34 (54%) were of female sex. The predominant clinical manifestations were poor weight gain or weight loss (92%, 58/63), poor feeding (84%, 53/63), skin hyperpigmentation (83%, 52/63), and female external genital anomalies (100%, 34/34). Laboratory abnormalities included hyponatremia (87%, 55/63), hyperkalemia (68%, 43/63), metabolic acidosis (68%, 43/63), and markedly elevated 17-hydroxyprogesterone (92%, 58/63), testosterone (89%, 56/63), and adrenocorticotropic hormone (81%, 51/63). Among 49 patients who underwent genetic testing, CYP21A2 variants were identified in 90% (44/49), with c.293-13A/C>G (33%, 30/91) and large deletions/gene conversions (29%, 26/91) being the most frequent; STAR (8%, 4/49) and HSD3B2 (2%, 1/49) variants were also detected. Following hormone replacement therapy, electrolyte disturbances were corrected in 57 cases, with significant reductions in 17-hydroxyprogesterone, adrenocorticotropic hormone, and testosterone levels (P<0.001).
CONCLUSIONS
CAH presenting in neonates or young infants is characterized by electrolyte imbalance, external genital anomalies, and abnormal hormone levels. Genetic testing enables definitive subtype classification; in CYP21A2-related CAH, c.293-13A/C>G is a hotspot variant. These findings underscore the clinical value of genetic testing for early diagnosis and genetic counseling in CAH. Citation:Chinese Journal of Contemporary Pediatrics, 2025, 27(11): 1367-1372.
Humans
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Adrenal Hyperplasia, Congenital/diagnosis*
;
Male
;
Female
;
Retrospective Studies
;
Infant
;
Infant, Newborn
9.Screening of Anti-Tumor Drugs that Enhance Antigen Presentation of AML Cells with TCR-Like Antibody.
Xiao-Ying YANG ; Bo TANG ; Hui-Hui LIU ; Wei-Wei XIE ; Shuang-Lian XIE ; Wen-Qiong WANG ; Jin WANG ; Shan ZHAO ; Yu-Jun DONG
Journal of Experimental Hematology 2025;33(5):1305-1311
OBJECTIVE:
To screen anti-tumor drugs that improve antigen processing and presentation in acute myeloid leukemia (AML) cells.
METHODS:
A TCR-like or TCR mimic antibody that can specifically recognize HLA-A*0201:WT1126-134 ( RMFPNAPYL) complex (hereafter referred to as HLA-A2:WT1) was synthesized to evaluate the function of antigen processing and presentation machinery (APM) in AML cells. AML cell line THP1 was incubated with increasing concentrations of IFN-γ, hypomethylating agents (HMA), immunomodulatory drugs (IMiD), proteasome inhibitors (PI) and γ-secretase inhibitors (GSI), followed by measuring of HLA-ABC, HLA-A2 and HLA-A2:WT1 levels by flow cytometry at consecutive time points.
RESULTS:
The TCR-like antibody we generated only binds to HLA-A*0201+WT1+ cells, indicating the specificity of the antibody. HLA-A2:WT1 level of THP-1 cells detected with the TCR-like antibody was increased significantly after co-incubation with IFN-γ, showing that the HLA-A2:WT1 TCR like antibody could evaluate the function of APM. Among the anti-tumor agents screened in this study, GSI (LY-411575) and HMA (decitabine and azacitidine) could significantly increase the HLA-A2:WT1 level. The IMiD lenalidomide and pomalidomide could aslo upregulate the expression of HLA-A2:WT1 complex under certain concentrations of the drugs and incubation time. As proteasome inhibitors, carfilzomib could significantly decreased the expression of HLA-A2:WT1, while bortezomib had no significant effect on HLA-A2:WT1 expression.
CONCLUSION
HLA-A2:WT1 TCR-like antibody can effectively reflect the APM function. Some of the anti-tumor drugs can affect the APM function and immunogenicity of tumor cells.
Humans
;
Leukemia, Myeloid, Acute/immunology*
;
Antineoplastic Agents/pharmacology*
;
Antigen Presentation/drug effects*
;
HLA-A2 Antigen/immunology*
;
Receptors, Antigen, T-Cell/immunology*
;
Cell Line, Tumor
;
Interferon-gamma
10.Three-dimensional finite element analysis of digital wire loop space maintainers for missing deciduous teeth.
Lijuan MA ; Yonghui TENG ; Yong WANG ; Yijiao ZHAO ; Xinyue ZHANG ; Qingzhao QIN ; Dong YIN
Journal of Peking University(Health Sciences) 2025;57(2):376-383
OBJECTIVE:
To establish a three-dimensional finite element model of a digital wire loop space maintainer for the mandible and primary tooth loss, in order to investigate the stress, deformation, and shear force experienced by patients with the loss of the second primary molar when wearing the wire loop space maintainer.
METHODS:
Cone beam computed tomography (CBCT) scans were performed on the patients to create a digital model of the mandible with the absence of the second primary molar using Mimics 21.0 software. A digital model integrating the crown's retention and the wire loop structure of the full crown and ring wire loop space maintainer was constructed using pediatric space maintainer design software, utilizing three different materials: cobalt-chromium alloy, polyether ether ketone (PEEK), and titanium alloy. In ANSYS Work Beach 2023 R2 software, vertical loads of 70 N, tilted 45° along the long axis of the tooth loads of 70 N, and a 10 N load on the surface of the wire loop were applied to the occlusal surfaces of models 46 and 84, simulating centric and lateral occlusions during chewing with the wire loop space maintainer in place. The stress states of the wire loop space maintainer and supporting teeth were analyzed.
RESULTS:
Under various loading conditions, the maximum principal stress of the ring wire loop space maintainer was significantly lower than that of the full crown. Stress contour maps indicated that the peak of the maximum principal stress occurred at the junction of the wire loop and crown structure, indicating that this area was more susceptible to fracture. The ring wire loop space maintainer made from PEEK material exhibited the lowest maximum shear stress on the internal organizational surfaces, with equivalent stresses of 23.18 MPa and 36.35 MPa for models 46 and 84, respectively. Stress contour maps demonstrated that the maximum stress on tooth 46 was located at its mesial, while the maximum stress on tooth 84 was situated near the root area on its distal, in contact with the wire loop space maintainer.
CONCLUSION
In cases of second primary molar loss, wearing the digital ring wire loop space maintainer can effectively distribute stress, and the ring wire loop space maintainer made from PEEK material reduces the stress experienced by supporting teeth to some extent, demonstrating its superiority in clinical application.
Finite Element Analysis
;
Humans
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Tooth, Deciduous
;
Cone-Beam Computed Tomography
;
Space Maintenance, Orthodontic/methods*
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Imaging, Three-Dimensional
;
Orthodontic Wires
;
Dental Stress Analysis
;
Mandible
;
Stress, Mechanical


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