BACKGROUND:The post-core crown system is an effective method for dental defect repair, but its repair outcomes are influenced by various factors;thereby, a further study is needed to optimize this method.OBJECTIVE:To investigate the stress distribution in different degrees of dental defect after post-core crown restoration under different occlusal contacts. METHODS:Three-dimensional models of the mandibular first molar were established by CT images, and models of complete natural teeth, six different defected teeth (total maxil ofacial slight and severe defects, distal middle maxil ofacial slight and severe defects, proximal middle maxil ofacial slight and severe defects) and two different post-core crowns (fiber post and zirconia post) were created by software. These models were imported into ANSYS software to analyze the stress distribution in dentin and periodontium under stable occlusal contact (ABC) and unstable occlusal contact (AC), respectively. RESULTS AND CONCLUSION:The stress in dentin and the periodontium after post-core crown restoration under AC was obviously higher than that under ABC, and AC affected the restored teeth more markedly. The post-core crown material with higher elastic modulus could induce higher stresses, and severe defected teeth showed higher stress distribution. Different defected types made no overt effects on the stress distribution in the periodontium. These results suggest that the B area contact is critical in regulating occlusal contacts of restoration.

Objective To investigate the effects of exogenous hydrogen sulfide on brain edema and injury and their mechanisms. Methods Sixty male SD rats were randomly divided into a sham operation group, an ischemia-reperfusion group, a 30 ppm hydrogen sulfide group, and a 60 ppm hydrogen sulfide group (n =15 in each group; 1 ppm =1 mg/L). A model of focal cerebral ischemia for 2 h and reperfusion for 24 h was induced by middle cerebral artery occlusion. The neurological scores were observed after 24 h cerebral ischemia-reperfusion. The cerebral infarction volume, the degree of brain edema, and the changes of blood-brain barrier permeability were measured. Western blotting was used to detect the expressions of occludin and zonula occludens-1 protein (ZO-1) in ischemic penumbra. Results Compared with the ischemia-reperfusion group, the neurological function scores in the 30 ppm and 60 ppm hydrogen sulfide group significantly increased in a dose-dependent manner (al P <0.05) and the neurological deficits and infarct volume reduced (al P < 0.05), and the
brain edema aleviated (al P < 0.05). The content of Evans blue in the ischemic brain tissue in the ischemia-reperfusion group increased significantly compare with the sham operation group (0.74 ±0.14 μg/100 mg vs. 0.19 ±0.06 μg/100 mg; P <0.05). The content of Evans blue in the brain tissue in the 30 ppm hydrogen sulfide group (0.55 ±0.10 μg/100 mg ) and the 60 ppm hydrogen sulfide group (0.35 ±0.08 μg/100 mg ) decreased significantly compared with the ischemia-reperfusion group (al P < 0.05), among them the 60 ppm hydrogen sulfide group was significantly lower than the 30 ppm hydrogen sulfide group (P <0.05). Western blot analysis showed that expression levels of occludin in penumbra (0.621% ±0.101% vs.0.787% ±0.087% vs.0.453% ± 0.127%; P <0.05) and ZO-1 (0.602% ±0.118% vs.0.778% ±0.805% vs.0.426% ±0.146; P <0.05) in the 30 ppm and 60 ppm hydrogen sulfide groups increased significantly compared with the ischemia-reperfusion group, among them, the expression levels of occludin and ZO-1 in the 60 ppm hydrogen sulfide group were significantly higher than those in the 30 ppm hydrogen sulfide group (al P < 0.05). Conclusions Inhalation of exogenous hydrogen sulfide can significantly attenuate brain edema after ischemia-reperfusion in a dose dependent manner, reduce infarct volume, and improve neurological function.Their mechanisms may be associated with inhibiting the downregulated expressions of occludin and ZO-1 and maintaining the integrity of the blood-brain barrier.

Objective To evaluate the curative effects of portal vein tumor emboli(PVTE)of hepatocellular carcinoma treated by CT-guided percutaneous ethanol injection(PEI).Methods Absolute ethanol was injected into the tumor embolus of portal vein guided by CT in twenty patients with hepatocellular carcinomas.The procedure was carried out one or two times each week one to three times as a course and one to two courses for a patient.The interval between two courses was one month and the patients were followed up for 6 months-5 years.Results Among the twenty patients,17(85%)were improved in different degrees after the treatment,with disappearence of the tumor emboli in 2(10%)and size stability or even smaller in 15 (75%),and finally no response in 3(15%).Conclusions CT-guided PEI is an effective method for patient with PVTE and proper selection of patient for the procedure is the key to obtain better curative effects.

Objective To evaluate the clinical value of percutaneous transcatheter selective right portal vein embolization(PVE)in treatment of primary hepatocellular carcinoma.Methods Twelve patients with unresectable hepatocellular carcinoma were treated with right percutaneous transcatbeter PVE under fluoroscopic guidance.Left hepatic lobe volume was measured by CT before and after PVE.Portal vein pressures and changes of liver function were also detected before and after the embolization.Results Right portal vein was embolized successfully in all 12 patients with compensatory hypertrophy of left hepatic lobe.Right hepatic lobe was successfully resected in 3 patients.There were no evidence of hepatic dysfunction and portal hypertension after PVE and also without complication.Conclusions Percutaneous transcathter portal vein branch embolization can induce atrophy of the embolized lobes with compensatory hypertrophy of the remnant liver,providing another operation chance for patients with unresectable hepatocellular carcinoma.

The application of Problem-based Learning(PBL) in prosthodontics accommodates the request of teaching reformation and also elevates the quality of students and teachers.PBL is a fine teaching method and deserves popularization.

Objective: To observe the effect of Tongxinluo (TXL) on homocysteine-induced rat’s cardiac micro vascular endothelial cell (RCMECs) injury and to study the oxidative stress mechanism. Methods: Primary RCMECs were cultured with tissue explants process, cell morphology was observed by inverted microscope and the cell was identiifed by CD31 immunolfuorescence method. RCMEC injury model was established by Homocysteine (Hcy) induction and the cells were divided into 5 groups: Control group, with normal cells, Hcy group, the cells were treated by Hcy at 10 mmol/L, Low-dose TXL group, Hcy treated cells were cultured with TXL at 100 mg/L, Middle-dose TXL (200 mg/L) group and high-dose TXL (400 mg/L) group. Cell survival rates were detected, supernatant levels of superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were examined, intracellular protein expressions of reactive oxygen species (ROS) and endothelial nitric oxide synthase (eNOS) were detected and mRNA expression of endothelin-1 (ET-1) was measured in different groups respectively. Results: Compared with Control group, Hcy group showed decreased cell survival rate (74.61 ± 2.88)% vs (100.00 ± 2.07)%, increased supernatant level of MDA (4.10 ± 0.18) nmol/ml vs (1.92 ± 0.10) nmol/ml, reduced SOD activity (7.55 ± 0.71) U/ml vs (20.77 ± 0.68) U/ml, elevated ROS level(38.17 ± 10.28) % vs (19.83 ± 2.97) %, up-regulated mRNA expression of ET-1 and down-regulated protein expression of eNOS. Compared with Hcy group, the above indexes were improved in each TXL group at different levels. Conclusion: TXL could decrease Hcy induced RCMECs injury, such protection was conducted by reducing the oxidative stress mechanism in cells.

Objective To evaluate the effectiveness of single balloon enteroscopy (SBE) in diagno-sing of suspected lesions in small intestine. Methods Data of 23 patients with suspected small intestinal disease, who underwent SBE (Olympus) between February 2009 and August 2009, were retrospectively studied. A total of 34 procedures were performed in 23 patients. The indications for the examination were suspected obscure gastrointestinal bleeding (n = 9), abdominal pain (n = 7), suspected intestinal tumor re-vealed by capsule endoscopy (n = 4), and Crohn disease (n = 3). Results The average preparation time of SBE was less than 5 minutes. The mean procedure time was 61±25 minutes and 67±28 minutes for the oral and anal routes, respectively. Examination of whole length of small intestine was achieved in 6 patients. The diagnostic rate of small-intestinal lesions was 60. 9%, and no severe complications including perforation occurred. Conclusion SBE is safe and easy to prepare and perform, which can be a useful diagnostic and therapeutic tool for suspected small bowel disease.

Objective:To identify the risk factors for moderate-to-severe pain in postanesthesia care unit (PACU) in the patients undergoing thoracic surgery.Methods:The medical records of patients of both sexes, aged 18-80 yr, of American Society of Anesthesiologists(ASA) physical status Ⅰ-Ⅲ, transferred to PACU with tracheal intubation from January 2019 to January 2020, were retrospectively collected.Combined intravenous-inhalational anesthesia was used during surgery.The patient′s age, gender, ASA physical status, smoking history, drinking history, history of non-thoracic surgery, history of hypertension, history of diabetes mellitus, and history of immune system disease were collected.The operation method, type of operation, operation time, intraoperative nerve block and use of opioids and dexmedetomidine were also collected.The consumption of rescue analgesics during PACU, occurrence of nausea and vomiting, and length of stay in PACU were also collected.Patients were divided into moderate-to-severe pain group (VAS score>3 points) and non-moderate-to-severe pain group (VAS score≤3 points) according to the VAS scores at rest and during activity at 10 min after extubation in PACU.Logistic regression analysis was used to identity the risk factors for moderate-to-severe pain in PACU.Results:A total of 1 698 patients were included in this study, the incidence of moderate-to-severe pain at rest was 46.70%, and the incidence of moderate-to-severe pain during activity was 54.12%.The results of logistic regression analysis showed that female, radical resection of esophageal cancer, mediastinal surgery, internal fixation for rib/sternal surgery were risk factors for moderate-to-severe pain in PACU, and increasing age, endoscopic surgery, intraoperative use of nerve block and dexmedetomidine were protective factors for moderate-to-severe pain in PACU in the patients undergoing thoracic surgery ( P<0.05). Conclusion:Female, radical resection of esophageal cancer, mediastinal surgery, and rib/sternal surgery are risk factors for moderate-to-severe pain in PACU in the patients undergoing thoracic surgery; increasing age, endoscopic surgery, intraoperative use of nerve block and dexmedetomidine are protective factors for moderate-to-severe pain in PACU in the patients undergoing thoracic surgery.

Epithelial-to-mesenchymal transition (EMT) plays a critical role in cancer metastasis,and is relevant to the inflammatory microenvironment.Lipopolysaccharide (LPS),a cell wall constituent of gram-negative bacteria,has been reported to induce EMT of cancer cells through TLR4 signal.We previously reported that LPS promoted metastasis of mesenchymallike breast cancer cells with high expression of cyclin D 1 b.However,the role of cyclin D1b in LPS-induced EMT has not been fully elucidated.In the present study,we described that cyclin D1b augmented EMT induced by LPS in MCF-7 breast cancer cells.Cyclin D1b markedly amplified integrin αvβ3 expression,which was further up-regulated under LPS stimulation.Our results showed ectopic expression of cyclin D1b promoted invasiveness of epithelial-like MCF-7 cells under LPS stimulation.Additionally,LPS-induced metastasis and EMT in MCF-7-D1b cells might depend on αvβ3 expression.Further exploration indicated that cyclin D1b cooperated with HoxD3,a transcription factor promoting αvβ3 expression,to promote LPS-induced EMT.Knockout of HoxD3 repressed LPS-induced EMT and αvβ3 over-expression in MCF-7 cells with high expression of cyclin D1b.Specifically,all these effects were in a cyclin D1a independent manner.Taken all together,LPS up-regulated integrin αvβ3 expression in MCF-7 cells with high expression of cyclin D 1b and induced EMT in breast cancer cells,which highlights that cyclin D1b may act as an endogenous pathway participating in exogenous signal inducing EMT in breast cancer cells.

Objective To investigate the evaluation of high-resolution computed tomography (HRCT) in patients with chronic obstructive pulmonary diseases (COPD), and the relationship with the pulmonary function test and BODE index.Methods 32 COPD patients and 22 normal controls were examined by pulmonary function test (PFT) and HRCT. The data of two groups were compared.Results The volume and pixel index (PI) in forced expiration were higher in the COPD group than those in the control group ( P<0.01), but there was no significant difference in Vin between two groups ( P>0.05). In the COPD group, Vex and Vin were negatively correlated with FEV1/FVC ( P<0.05) respectively. There were no correlation between Vin, Vex and FEV1% pre in the COPD patients ( P>0.05) respectively. Vin and Vex were not correlated with BODE index (all P>0.05) respectively. The ratio of Vex/Vin was positively correlated with BODE index ( P<0.05), and not correlated with FEV1/FVC ( P>0.05). PI910ex was positively correlated with BODE index ( P<0.01), and negatively correlated with FEV1%pre, FEV1/FVC (all P<0.05) respectively.Conclusion The pulmonary function of COPD patients can be evaluated by HRCT, especially by PI910ex.