1.Study on mechanical stability of maxillary LeFort Ⅰ type osteotomy after fixation with mortise and tenon and absorbable plate
Yankun ZHANG ; Zixuan SHEN ; Ran ZHANG ; Lijia DONG ; Yu TIAN ; Li LU ; Mingliang YANG ; Guangqi YAN
Chinese Journal of Stomatology 2025;60(6):635-643
Objective:To evaluate the mechanical stability of the bone block after LeFort Ⅰ osteotomy with maxillary advancement using absorbable plates fixed with tenon-and-mortise structures.Methods:This study developed three finite element models: one for the maxillary LeFort Ⅰ osteotomy with anterior advancement fixed with absorbable plates (Model 1); another for the maxillary LeFort Ⅰ osteotomy with anterior advancement fixed with absorbable plates assisted by tenon-and-mortise structures (Model 2); and the last one for the maxillary LeFort Ⅰ osteotomy with anterior advancement fixed with titanium plates and screws (Model 3). Simulated occlusal forces were applied on the anterior and posterior teeth in each model. The displacement changes of the nasal-palatine point (NP) and posterior nasal spine point (PNS) in the finite element coordinate system were compared and analyzed. The Mises equivalent stress distributions of the metal and absorbable plates were also examined to assess the mechanical stability of the three finite element models. Clinical data from 45 patients with dentofacial deformities treated from January 2017 to January 2023 at the Stomatology Hospital of China Medical University were collected. The age of the patients was 21±3 years. Among these, 15 patients had absorbable plates for fixation, 15 had absorbable plates assisted by tenon-and-mortise structures, and 15 had titanium plates and screws fixation after maxillary advancement. All patients underwent preoperative (T0), postoperative 3 days (T1), and 6 months (T2) spiral CT scans. The CT data in DICOM format were input into digital software, which was used to calculate the distances from the NP and PNS points to the horizontal plane (HP), right sagittal plane (FZSR), and coronal plane (CP) at T1 and T2. The distances at T1 and T2 were statistically analyzed using the Wilcoxon signed-rank test with SPSS 20.0, and a P value of<0.05 was considered statistically significant.Results:The finite element analysis showed that in the absorbable plate-only fixation group, the maximum displacement of the NP point (mm) under anterior and posterior tooth force conditions were 0.6 and 0.12, respectively, and for the PNS point, the maximum displacements were 0.5 and 0.11. In the tenon-and-mortise-assisted absorbable plate fixation group, the displacement of the NP point was 0.40 and 0.02 mm, and the displacement of the PNS point was 0.5 and 0.015 mm. In the titanium plate-screw fixation group, the NP point displacement was 0.33 and 0.055 mm, and the PNS point displacement was 0.16 and 0.1 mm. The Mises equivalent stress on the absorbable plates with tenon-and-mortise structure was significantly lower than that in the absorbable plate-only fixation group, while the titanium plate experienced the highest Mises equivalent stress. The clinical data analysis showed that in the horizontal direction, the postoperative stability of the three fixation methods was similar. However, in the vertical and anterior-posterior directions, the absorbable plate-only fixation group showed significant differences in the distances of PNS-HP, PNS-CP, and NP-CP between T1 and T2 ( P=0.018, P=0.009, P=0.017), suggesting significant postoperative bone displacement. In contrast, the tenon-and-mortise-assisted absorbable plate fixation group and the titanium plate-screw fixation group showed no significant differences in displacement during surgery and postoperatively(all P>0.05), demonstrating higher stability. Conclusions:The tenon-and-mortise-assisted absorbable plate fixation provides comparable stability to titanium plate fixation in clinical results, and it is more stable than absorbable plate-only fixation. In the mechanical study, when force was applied on the anterior teeth, the stability of the tenon-and-mortise-assisted absorbable plate fixation was slightly less than that of titanium plate fixation, but when posterior teeth were used, its stability exceeded both titanium plate fixation and absorbable plate-only fixation. The tenon-and-mortise-assisted absorbable plate fixation serves as an effective alternative to titanium plate fixation after LeFort Ⅰ osteotomy.
2.Recurrent adult Langerhans cell histiocytosis complicated with diabetes insipidus: report of 1 case and review of literature
Chen CHEN ; Ruixue LI ; Yankun YU ; Weixia NONG ; Xin PAN
Journal of Leukemia & Lymphoma 2025;34(9):548-552
Objective:To improve the understanding of recurrent adult Langerhans cell histiocytosis complicated with diabetes insipidus.Methods:The clinical data of 1 patient with recurrent adult Langerhans cell histiocytosis complicated with diabetes insipidus admitted to the First Affiliated Hospital of Shihezi University in January 2024 was collected. Its disease characteristics, effectiveness and safety of treatment scheme were analyzed, and literatures were reviewed.Results:The 42-year-old female patient was diagnosed as Langerhans cell histiocytosis in June 2021. After treated with cytarabine, the symptoms improved and the patient achieved sustained remission. In January 2024, the patient was admitted to the hospital due to pain in the middle part of the front chest. The PET-CT results indicated disease progression, which was manifested by new bone destruction, enlarged lymph nodes, and increased nocturnal urination, with urine volume of 3-5 L within 24 h. Based on the clinical manifestations such as cranial bone lesions, periorbital soft tissue lesions, and enlarged lymph nodes at onset, multiple systems and multiple foci involvement was considered. The diagnosis of combined diabetes insipidus was confirmed through the water deprivation and pressure test. After MACOP-B regimen (doxorubicin liposome, cyclophosphamide, vincristine, bleomycin, prednisone), the patient's bone pain was completely relieved, and no serious complications occurred.Conclusions:Recurrent adult Langerhans cell histiocytosis complicated with diabetes insipidus is rare; MACOP-B regimen is safe and effective in treatment of the disease.
3.Study on mechanical stability of maxillary LeFort Ⅰ type osteotomy after fixation with mortise and tenon and absorbable plate
Yankun ZHANG ; Zixuan SHEN ; Ran ZHANG ; Lijia DONG ; Yu TIAN ; Li LU ; Mingliang YANG ; Guangqi YAN
Chinese Journal of Stomatology 2025;60(6):635-643
Objective:To evaluate the mechanical stability of the bone block after LeFort Ⅰ osteotomy with maxillary advancement using absorbable plates fixed with tenon-and-mortise structures.Methods:This study developed three finite element models: one for the maxillary LeFort Ⅰ osteotomy with anterior advancement fixed with absorbable plates (Model 1); another for the maxillary LeFort Ⅰ osteotomy with anterior advancement fixed with absorbable plates assisted by tenon-and-mortise structures (Model 2); and the last one for the maxillary LeFort Ⅰ osteotomy with anterior advancement fixed with titanium plates and screws (Model 3). Simulated occlusal forces were applied on the anterior and posterior teeth in each model. The displacement changes of the nasal-palatine point (NP) and posterior nasal spine point (PNS) in the finite element coordinate system were compared and analyzed. The Mises equivalent stress distributions of the metal and absorbable plates were also examined to assess the mechanical stability of the three finite element models. Clinical data from 45 patients with dentofacial deformities treated from January 2017 to January 2023 at the Stomatology Hospital of China Medical University were collected. The age of the patients was 21±3 years. Among these, 15 patients had absorbable plates for fixation, 15 had absorbable plates assisted by tenon-and-mortise structures, and 15 had titanium plates and screws fixation after maxillary advancement. All patients underwent preoperative (T0), postoperative 3 days (T1), and 6 months (T2) spiral CT scans. The CT data in DICOM format were input into digital software, which was used to calculate the distances from the NP and PNS points to the horizontal plane (HP), right sagittal plane (FZSR), and coronal plane (CP) at T1 and T2. The distances at T1 and T2 were statistically analyzed using the Wilcoxon signed-rank test with SPSS 20.0, and a P value of<0.05 was considered statistically significant.Results:The finite element analysis showed that in the absorbable plate-only fixation group, the maximum displacement of the NP point (mm) under anterior and posterior tooth force conditions were 0.6 and 0.12, respectively, and for the PNS point, the maximum displacements were 0.5 and 0.11. In the tenon-and-mortise-assisted absorbable plate fixation group, the displacement of the NP point was 0.40 and 0.02 mm, and the displacement of the PNS point was 0.5 and 0.015 mm. In the titanium plate-screw fixation group, the NP point displacement was 0.33 and 0.055 mm, and the PNS point displacement was 0.16 and 0.1 mm. The Mises equivalent stress on the absorbable plates with tenon-and-mortise structure was significantly lower than that in the absorbable plate-only fixation group, while the titanium plate experienced the highest Mises equivalent stress. The clinical data analysis showed that in the horizontal direction, the postoperative stability of the three fixation methods was similar. However, in the vertical and anterior-posterior directions, the absorbable plate-only fixation group showed significant differences in the distances of PNS-HP, PNS-CP, and NP-CP between T1 and T2 ( P=0.018, P=0.009, P=0.017), suggesting significant postoperative bone displacement. In contrast, the tenon-and-mortise-assisted absorbable plate fixation group and the titanium plate-screw fixation group showed no significant differences in displacement during surgery and postoperatively(all P>0.05), demonstrating higher stability. Conclusions:The tenon-and-mortise-assisted absorbable plate fixation provides comparable stability to titanium plate fixation in clinical results, and it is more stable than absorbable plate-only fixation. In the mechanical study, when force was applied on the anterior teeth, the stability of the tenon-and-mortise-assisted absorbable plate fixation was slightly less than that of titanium plate fixation, but when posterior teeth were used, its stability exceeded both titanium plate fixation and absorbable plate-only fixation. The tenon-and-mortise-assisted absorbable plate fixation serves as an effective alternative to titanium plate fixation after LeFort Ⅰ osteotomy.
4.The suppression mechanisms of quercetin in retinal and choroidal neovascularization through integrin signal pathway
Yankun YUE ; Haiwei WANG ; Yu DENG ; Mo TIAN ; Yinlin WANG ; Enkui ZHANG
Chinese Journal of Experimental Ophthalmology 2018;36(8):602-607
Objective To investigate the mechanisms of quercetin in retinal angiogenesis via in vitro and in vivo studies.Methods Human umbilical vein endothelial cells (HUVECs) was used in in vitro study,and oxygen-induced retinopathy (OIR) and laser-induced choroidal neovascularization (CNV) animal models were used in in vivo study.In the in vitro cell study,normal control group,VEGF-165 treatment group and VEGF-165 combined with quercetin treatment group were used.Cell counting kit-8 (CCK8) and Transwell were used to measure HUVECs cell viability,including proliferation and migration.OIR and CNV animal models were administrated through intraperitoneal injection of quercetin,and the non-perfusion area and CNV aera were evaluated.Western blot assay was used to detect the expression of integrin α5 and integrin β3 expression.In the animal study,18 breastfeeding mice and 18 infant mice were randomly divided into normal control group,model control group and quercetin treatment group,6 for each group.The animal feeding and use was in accordance with the standards set by the ARVO,and the experiment was approved by the Ethic Committee for Experimental Animal of Fu Xing Hospital,Capital Medical University (2016-KY-0036).Results In the in vitro study,VEGF-165 (20 ng/ml) promoted the proliferation and migration of HUVECs,while quercetin (50 μmol/L) inhibited HUVECs proliferation and migration significantly,comparing to the VEGF-165 treatment group (proliferation:Fgroups =18.51,P =0.00;migration:F =85.74,P =0.00).In the in vivo studies,quercetin 20 mg/(kg·day) decreased the non-perfusion area and CNV area comparing to the untreated groups,with significant differences between them (t =6.02,P =0.00;t =5.79,P =0.00).Besides,quercetin down-regulated the expression of integrin α5 and integrin β3 significantly both in the in vitro and in vivo studies.Western blot test showed that integrin α5 and integrin β3 in VEGF-165+quercetin processing 24 hours group were significantly decreased than those in the VEGF-165 group,with significant differences between them (t =4.46,P<0.05;t =5.18,P<0.01).Compared with the VEGF-165 +quercetin 24 hours group,the integrin α5 and integrin β3 in VEGF-165 +quercetin processing 48 hours group were increased,but they were still significantly increased than those in the VEGF-165 group,with significant differences between them (t =6.54,P < 0.05;t =7.17,P < 0.01).For the animal studies,quercetin also inhibited the levels of integrin α5 and integrin β3 in OIR and CNV models (t =5.44,13.52;both at P=0.00).Conclusions Quercetin can inhibit the retinal and choroidal neovascularization through integrin pathway,which provides a new treatment strategy for clinical therapy.
5.Proliferation-promoting effect of umbilical cord mesenchymal stem cells on co-cultured bovine mammary gland epithelial cells
Yankun ZHAO ; Wei SHAO ; Chenglong LUO ; Xiong YU
Acta Laboratorium Animalis Scientia Sinica 2017;25(4):391-398
Objective To explore the proliferation-promoting effect of bovine mammary gland epithelial cells (BMECs) co-cultured with umbilical cord mesenchymal stem cells (UC-MSCs) in serum-free culture mediuum.Methods Bovine UC-MSCs and BMECs were selected for co-culturing in direct or indirect contact.In the direct contact culture groups, UC-MSCs and BMECs were co-cultured at concentration ratios of 2∶1, 1∶1, 1∶2, 1∶3, 1∶4, 1∶5, and 1:10, respectively.In the indirect contact culture group, the supernatant of UC-MSCs was used as the conditioned medium to re-suspend BMECs.In the control groups, UC-MSCs and BMECs were cultured alone.The cell growth status in each group was observed at 0, 4, 8, 12, 24, 36, 48, 60, 72 h after culture, and cell proliferation was detected by cell counting kit-8 (CCK-8) assay.Results At 48 h, the optical density of the conditioned medium-BMECs group was significantly higher compared with the control groups (P<0.05).Meanwhile, the optical density in the direct contact group at a concentration ratio of 1∶2 reached the peak, which was extremely significantly higher compared with the control groups (P<0.01) and significantly higher compared with the other direct contact culture groups and the conditioned medium-BMECs group (P<0.05).Conclusions Co-culture of UC-MSCs and BMECs in serum-free culture medium is capable to promote the proliferation of BMECs, and the co-culture by cell-to-cell contact has a better effect.The optimal concentration ratio of UC-MSCs to BMECs is 1∶2, and the optimal culture time is 48 h.
6.Melanotic oncocytic metaplasia of the nasopharynx.
Bao-cheng DONG ; Hao TIAN ; Xin-qi JIA ; Gelin LI ; Cheng LU ; Yankun ZHANG ; Xiaoming ZHU ; Fang YU
Chinese Journal of Otorhinolaryngology Head and Neck Surgery 2005;40(7):549-550
Aged
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Female
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Humans
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Male
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Melanosomes
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Metaplasia
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Middle Aged
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Nasopharynx
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cytology
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pathology
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Oxyphil Cells
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cytology

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