Objective: To estalish a rat model system in which periapical lesions were induced by pulp exposure and infection from the oral environment. Methods: The pulps of mandibular molar of 16 SD rats were surgically exposed and kept open to be induced for infection from the oral environment. The rats were killed 1, 2, 3, 4 weeks after operation respectively. Radiographic image analysis was performed by means of computer linked to a video image digital analysis system. In addition, specimens were decalicified, sectioned, HE stained and examined under microscope. Results: Periapical lesions were readily detectable as early as 1 week after pulp exposure. A significant increase in lesion area was detected from 1 to 3 weeks in a time-dependent manner, the lesion declined a little bit in 4 weeks. Slight inflammatory cell infiltration and alveolar bone resorption were observed in the periapical tissue in the 1-week-samples, total pulp necrosis in the 2-week-samples, apical abscess and bone destruction in the 3-week-samples. Decreased infiltration and the matured osteoblasts were found on the surface of the bone in the 4-week-samples. Conclusion: Pulp exposure can induce periapical lesion in rat. A period of rapid lesion development occurs between day 7 and day 21 after pulp exposure (active phase), and a period of slower development follows thereafter (chronic phase).

Objective To study the effect of CO2 pneumoperitoneum on the anti-apoptotic capability of gallbladder carcinoma cell line (GBC-SD).Methods The CO2 pneumoperitoneum was established in vitro.After GBC-SD cells were exposed to CO2 pneumoperitoneum at 12 mmHg for 1,2,3,4 h,the expressions of survivin mRNA was examined by RT-PCR.The untreated GBC-SD cells served as control.Results Under a pressure of 12 mmHg,the expressions of survivn had an increasing tendency with the exposure time.Conclusions Under certain pressure and within certain exposure time,CO2 pneumoperitoneum could improve anti-apoptotic capability of GBC-SD cells,which may be one of the mechanisms of the promoting effect of carbon dioxide pneumoperitoneum on malignant cell growth.

Objective We are entering a time when more and more digital images are being introduced to the operating room to enhance surgical outcomes .At the Surgical Simulation Research Lab of the University of Alberta, we developed a technology to superimpose a 3-dimentional (3D) breast model on top of the surgical site to guide a breast reconstruction procedure .Methods The breast models were created from the patient's magnetic resonance images .Our technician modified the breast model by taking data from pre-surgical scanning or from the healthy side of the breast .In the simulated environment , motion sensors were placed on the chest of the patient to capture the movements of the patient during the procedure, which were used to adjust the orientation of the 3D model to ensure a perfect mapping of the surgical site.Results Visual guidance was successfully displayed on top of the surgical site .Motion tracking captured movements of the simulated patient and was used for adjusting the 3D model in a short period of time.Conclusions Feasibility test on this innovative technology is reported in this short paper . We expect the same technology can be applied to other reconstruction surgical procedures in the future .

Objective We are entering a time when more and more digital images are being introduced to the operating room to enhance surgical outcomes .At the Surgical Simulation Research Lab of the University of Alberta, we developed a technology to superimpose a 3-dimentional (3D) breast model on top of the surgical site to guide a breast reconstruction procedure .Methods The breast models were created from the patient's magnetic resonance images .Our technician modified the breast model by taking data from pre-surgical scanning or from the healthy side of the breast .In the simulated environment , motion sensors were placed on the chest of the patient to capture the movements of the patient during the procedure, which were used to adjust the orientation of the 3D model to ensure a perfect mapping of the surgical site.Results Visual guidance was successfully displayed on top of the surgical site .Motion tracking captured movements of the simulated patient and was used for adjusting the 3D model in a short period of time.Conclusions Feasibility test on this innovative technology is reported in this short paper . We expect the same technology can be applied to other reconstruction surgical procedures in the future .

Neural crest stem cells originated from hair follicle (epidermal neural crest stem cell, EPI-NCSC) are easy to obtain and have potentials to differentiate into various tissues, which make them eminent seed cells for tissue engineering. EPI-NCSC is now used to repair nerve injury, especially, the spinal cord injury. To investigate their effects on repairing peripheral nerve injury, EPI-NCSC from a GFP-SD rat were primarily cultured on coated dishes and on a poly lactic acid coglycolic acid copolymer (PLGA) membrane. Methyl thiazolyl tetrazolium (MTT) assay showed that the initial adhesion rate of EPI-NCSC was 89.7% on PLGA membrane, and the relative growth rates were 89.3%, 87.6%, 85.6%, and 96.6% on the 1st, 3rd, 5th, 7th day respectively. Cell cycles and DNA ploidy analysis demonstrated that cell cycles and proliferation indexes of cultured EPI-NCSC had the same variation pattern on coated dishes and PLGA membrane. Then cultured EPI-NCSC were mixed with equal amount of extracellular matrix and injected into a PLGA conduit to connect a 10 mm surgery excision gap of rat sciatic nerve, Dulbecco's Modified Eagle's medium (DMEM) was used to substitute EPI-NCSC in the control group. After four weeks of transplantation, the defected sciatic nerve achieved a histological restoration, the sensory function of rat hind limb was partly recovered and the sciatic nerve index was also improved. The above results showed that a PLGA conduit filled with EPI-NCSC has a good repair effect on the peripheral nerve injury.
Animals ; Cells, Cultured ; Neural Crest ; cytology ; Neural Stem Cells ; cytology ; Rats ; Rats, Sprague-Dawley ; Sciatic Nerve ; pathology ; Spinal Cord Injuries ; Stem Cell Transplantation ; Tissue Engineering

Objective To study mechanics characteristics of two cooperative reconfigurable planetary robots when they get across an obstacle, and to find out the relationship between the maximum height of a stair with the configuration of the two-robot, and to find some restrictions of kinematics for the cooperation. Methods Multirobot cooperation theory is used in the whole study process. Inverse kinematics of the robot is used to form a desired configuration in the cooperation process. Static equations are established to analyze the relations between the friction factor, the configuration of robots and the maximum height of a stair. Kinematics analysis is used to find the restrictions of the two collaborative robots in position, velocity and acceleration. Results 3D simulation shows that the two cooperative robots can climb up a stair under the condition of a certain height and a certain friction factor between robot wheel and the surface of the stair. Following the restrictions of kinematics, the climbing mission is fulfilled successfully and smoothly. Conclusion The maximum height of a stair, which the two cooperative robots can climb up, is involved in the configuration of robots, friction factor between the stair and the robots. The most strict restriction of the friction factor does not appear in the horizontal position. In any case, the maximum height is smaller than half of the distance between the centroid of robot1 with the centroid of robot2. However, the height can be higher than the radius of one robot wheel, which profit from the collaboration.

Objective:To study the clinical significance of early detection of soluble growth stimulating gene 2 protein (sST2) and prealbumin (PAB) in patients with chronic pulmonary heart disease (CPHD) complicated with refractory heart failure.Methods:From September 2017 to June 2019, 112 CPHD patients complicated with refractory heart failure were admitted to Hengshui People's Hospital. The selected patients met the revised guidelines for the diagnosis and treatment of chronic obstructive pulmonary disease (2013 revision) and the cardiac function grade Ⅲ-Ⅳ according to the grading criteria of the New York Cardiology Society. Cardiogenic shock, severe liver and kidney dysfunction, malignant tumors, anemia, and autoimmune diseases were excluded. Patients were divided into the high PAB group (≥200 mg/L) and the low PAB group (<200 mg/L) according to the PAB level on admission. The pulmonary artery systolic blood pressure (PASP), pulmonary artery mean pressure (MPAP), and left ventricular ejection fraction (LVEF) were observed in the two groups before and after the treatment. PAB, total bilirubin (TBIL), hypersensitive C reactive protein (hs-CPR), N-terminal B type brain natriuretic peptide (NT-proBNP) and sST2 levels were detected. Measurement data were expressed in terms of mean ± standard deviation, the counting data were compared using χ 2 test. Correlation analysis was conducted using Spearman correlation test. Results:There were 40 cases in the high PAB group and 72 cases in the low PAB group. There were no statistically significant differences in general data between the high PAB and low PAB groups ( P>0.05). Hospitalization time was significantly different between the two groups ( P<0.05). Before the treatment, there were no significant differences in PASP, MPAP, NT-proBNP and LVEF between the two groups ( P>0.05). High sST2 was significantly different between the two groups ( P<0.05). After the treatment, PASP, MPAP, NT-proBNP and sST2 were decreased in both groups, and the improvement was more obvious in the high PAB group than in the low PAB group, with statistical significance ( P<0.05). Before the treatment, the levels of TBIL and hs-CPR were not statistically different between the high PAB and low PAB groups ( P>0.05). However, the levels of TBIL and hs-CPR were beyond the normal range. After the treatment, TBIL and hs-CPR were decreased in both groups, and there was statistically significant difference between the two groups ( P<0.05). Spearman correlation analysis showed that PAB was negatively correlated with sST2 ( r=-0.778, P=0.001). There was a positive correlation between cardiac function and sST2 ( r=0.569, P=0.034), hospitalization time ( r=0.572, P=0.033) in patients with refractory heart failure. The higher the sST2 of CPHD with refractory heart failure, the longer the patient hospitalization time, and the more serious the heart failure was. The area under the combined ROC curve of PAB and sST2 was 0.756. CPHD patients with refractory heart failure had the greatest predictive value. Conclusion:The combined test of sST2 and PAB can evaluate the condition and outcome of CPHD patients with refractory heart failure, and guide the clinic.

Objective To investigate the protective effect of multidrug resistant associated protein 4 (MRP4) inhibitor on rats with sepsis-induced acute lung injury (ALI). Methods Sixty Sprague-Dawley (SD) rats were randomly divided into sham group, sepsis group and MRP4 inhibitor MK571 treatment group, with 20 rats in each group. Sepsis model was reproduced by cecal ligation and puncture operation (CLP), and the rats in sham group were only received celiotomy without ligation and puncture. Rats in MK571 treatment group were intraperitoneally injected with MRP4 inhibitor MK571 (20 mg/kg) 30 minutes before model reproduction, while rates in sham group and sepsis group were given the same amount of normal saline. Twenty-four hours later, the femoral artery blood of mice was collected, and arterial blood gas analysis was measured. Serum tumor necrosis-α (TNF-α) was determined by enzyme-linked immunosorbent assay (ELISA). The lung tissues were collected, and the wet/dry weight ratio (W/D) was calculated. The expression of MRP4 protein in lung tissue was determined by Western Blot. Results Compared with sham group, arterial blood pH value and arterial partial pressure of oxygen (PaO2) were significantly lowered [pH value: 7.18±0.03 vs. 7.40±0.03; PaO2 (mmHg, 1 mmHg = 0.133 kPa): 63.15±6.24 vs. 98.05±2.58], while arterial partial pressure of carbon dioxide (PaCO2) was dramatically higher in the sepsis group (mmHg: 56.60±8.30 vs. 37.85±3.18), serum TNF-α level in the sepsis group was significantly increased (ng/L: 146.24±19.99 vs. 25.77±9.83), the W/D ratio of lung tissue was significantly increased (7.75±0.47 vs. 4.09±0.58), and the expression of MRP4 protein was up-regulated in the sepsis group (gray value: 0.153±0.006 vs. 0.087±0.005, all P < 0.05). Compared with the sepsis group, arterial blood pH value (7.30±0.02 vs. 7.18±0.03) and PaO2 (mmHg: 80.30±5.34 vs. 63.15±6.24) were significantly elevated in the MK571 treatment group, while PaCO2 was dramatically decreased (mmHg: 29.25±3.24 vs. 56.60±8.30), the serum level of TNF-α was significantly decreased (ng/L: 97.96±16.72 vs. 146.24±19.99), the W/D ratio of lung tissue was significantly reduced (5.89±0.51 vs. 7.75±0.47), and MRP4 protein expression was significantly down-regulated (gray value: 0.124±0.006 vs. 0.153±0.006, all P < 0.05). Conclusion MRP4 inhibitor may improve lung function in rats with sepsis-induced ALI by down-regulating MRP4 protein expression and reducing levels of inflammatory cytokines, which exerts protective effect on ALI.

Objective To explore the difference between the stapes prosthesis surgery with microscope and with otoscope. Methods Fifty-four patients with otoselerosis accepted stapes prosthesis surgery with the same kind of stapes prosthesis, done in the same operative method by the identical surgeon.All the operations were done with microscopes or with otoscopes. The operative difference and therapeutic effects between microscope surgery and otoscope surgery were analysed. Results There was no difference in the postoperative heating improvement between microscope surgery and otoscope surgery; the operative time of microscope surgery [(30±7)] min was much shorter than that of otoscope surgery [(60±5)] min,with significant statistical difference. Conclusions Stapes prosthesis surgery with microscope, which has advantages of bimanualness, easiness, and short operative time, is much better than that with otoscope.Thus, microscope is still the preferred magnifying equipment in stapes prosthesis surgery.

Objective To explore the protective effect of vitamin E on the rabbit bladder after partial outlet obstruction artificially setup. Methods A total of 28 New Zealand white male rabbits were divided into 4 groups (group A in 6,group B in 6,group C in 8 and group D in 8).Group A,B and C were fed a regular diet,and group D were placed on a diet enriched with 600 mg vitamin E.After 4 weeks partial outlet obstruction was created in groups C and D,while group B underwent sham operation. After 4 weeks of obstruction each rabbit was sedated and cystometry was repeated.After cystometry the bladder was weighed.The gene expression of sarcoplasmic endoplasmic reticulum,calcium,magnesium,adenosine triphosphatase (SERCA2) in bladder was detected by using RT-PCR assay,while the protein level of SERCA2 was measured by Western blot analysis. Results All parameters measured were approximately identical in nomal rabbits(Group A) and shum operation rabbits(group B).Thus,these 2 groups were combined as the control group(Group A and B).Partial outlet obstruction resulted in bladder weight increased significantly in obstructed groups given vehicle group C(13.07?1.71)g and those vitamin E group D(11.80?2.01)g,4-fold higher than in the control group (2.81?0.30)g(P