BACKGROUND: Currently, acid etching and bonding technology have been widely used in clinical stomatology. Data have indicated that the main content of inorganic elements (calcium and phosphorus) has a certain difference between the dental enamel and dentin of the young and adult permanent teeth. OBJECTIVE:To measure the content of main inorganic elements, calcium and phosphorus, in the dental enamel and dentin from young and adult permanent teeth with spectrophotometry and ethylene diamine tetraacetie acid titration method. METHODS:Each 20 adult and young permanent teethin vitrowere selected. Plaster stone and water was mixed; when it was nearly dried, the teeth were verticaly cast in the mixture and the tooth surface was exposed. The models were cut into the slices using syj-200 precision cutting machine, and then the slices were put into nitric acid and dissolved through heater to prepare standard solution. At last, the concentrations of calcium and phosphorus in the hard tissue of both young and adult permanent teeth were measured with spectrophotometric method and titration method. RESULTS AND CONCLUSION:The content of calcium and phosphorus and calcium/phosphorus ratio in the hard tissue of young permanent teeth were less than those of adult permanent teeth (P < 0.05), reflecting that the organic matter content was more than that in adult permanent teeth, but their mineralized degree was inferior to that of adult permanent teeth (P < 0.05). These findings indicate that the young permanent teeth are more acid proof than the adult permanent teeth; therefore, the acid etching time can be properly prolonged for young permanent teeth in clinical treatment, in order to achieve better effects.

Objective: To determine the changes of serum Tau protein, glial fibrillary acidic protein (GFAP), tumor necrosis factor alpha (TNF-α), and malonaldehyde (MDA) in rats after blast-related traumatic brain injury (BTBI) and to provide relative information for further studies on BTBI mechanism and seek specific biomarkers for BTBI.
Methods: Ninety male Sprague-Dawley rats were randomly assigned into three groups: control group, moderate blast injury group, and severe blast injury group (n=30 for each). Rats in the moderate and severe blast injury groups were respectively exposed to corresponding levels of BTBI. After explosion, serum levels of Tau, GFAP, TNF-α, and MDA in each group were determined by Elisa assay at different time points after injury (8 h, 24 h, 3 d, and 6 d). The extent of brain damage was detected by Nissl staining and TUNEL assay.
Results: Serum levels of Tau and GFAP rapidly increased and reached the peak at 24 h after either moderate or severe blast injury. All the values were significantly higher than control group at all time points (P<0.05). Serum TNF-α level of both injury groups peaked at 8 h after BTBI and stayed significantly higher than control group at all time points (P<0.05). Serum MDA of two injury groups began to significantly increase at 3 d and the level stayed significantly higher than control group until 6 d (P<0.05). Moreover, unlike the other biomarkers, serum MDA of severe blast injury group was significantly higher than moderate blast injury group at 6 d (P<0.05).
Conclusion: The changes of serum Tau, GFAP, and TNF-αshowed a good sensitivity at the acute phase after BTBI (within 24 h). However, their specificity and correlation with the extent of injury were limited in this experiment. Moreover, although the change of serum MDA showed a poor sensitivity and specificity to the diagnosis of BTBI during the first few days, it can reflect the injury degree at 6 d after injury. Therefore, further studies are needed to improve the methods of detecting more serum markers and investigate the significance of multiple markers in diagnosing BTBI.

Objective To express nonstructural protein 2 transactivated protein (NS2TP) of hepatitis C virus (HCV) in the prokaryotic expression system and prepare polyclonal antibody,and to study the expressions in different liver tissues.Methods NS2TP gene was amplified by polymerase chain reaction (PCR) technique and cloned into the prokaryotic expression vector pET-32a(+),which was transformed into E.coli BL21.The protein was induced by isopropyl thiogalactose (IPTG) and analyzed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and confirmed by Western blotting assay.The recombinant protein were expressed and purified in a large amount.The rabbit was immunized with the purified protein to prepare polyelonal antibody.The liver tissues of patients with chronic HCV infection and healthy controls were detected by immunohistochemistry method.Results The recombinant NS2TP protein (relative molecular mass:33×103 ) and polyclonal antibody with high titer and specificity were successfully prepared.NS2TP expressions in the liver of patients with chronic HCV infection were higher than those of healthy controls,and were mainly distributed in the nucleus of hepatocytes.Conclusions The NS2TP expression level and intracellular location in liver tissue of patients with chronic HCV infection are understanded,which could bring new clues for further study of the biological function of NS2TP and the pathogenesis of HCV infection.

Objective To explore the effects of deletion of protein 4.1R on hepatocyte proliferation,apoptosis,and glycolysis and the molecular mechanisms.Methods A 4.1R-/-HL-7702 cell line was constructed using CRISPR/Cas9 technique,and with 4.1R+/+HL-7702 cells as the control,its proliferative capacity and cell apoptosis were assessed using CCK-8 assay,EdU-488 staining,flow cytometry and Annexin V-FITC/PI staining at 24,48,72 h of cell culture.The changes in glucose uptake,lactate secretion,ATP production and pH value of the culture supernatant of 4.1R-/-HL-7702 cells were determined.The mRNA expressions of the key regulatory enzymes HK2,PFKL,PKM2 and LDHA in glycolysis were detected with qRT-PCR,and the protein expressions of AMPK,p-AMPK,Raptor and p-Raptor were determined using Western blotting.Results Western blotting and sequencing analysis both confirmed the successful construction of 4.1R-/-HL-7702 cell line.Compared with the wild-type cells,4.1R-/-HL-7702 cells exhibited a lowered proliferative activity with increased cell apoptosis.The deletion of protein 4.1R also resulted in significantly decreased glucose uptake,lactate secretion and ATP production of the cells and increased pH value of the cell culture supernatant.qRT-PCR showed significantly decreased mRNA expressions of the key regulatory enzymes in glycolysis in 4.1R-/-HL-7702 cells.Compared with those in HL-7702 cells,the expression levels of AMPK and Raptor proteins were decreased while the expression levels of p-AMPK and p-Raptor proteins increased significantly in 4.1R-/-HL-7702 cells.Conclusion Deletion of protein 4.1R in HL-7702 cells results in reduced proliferative capacity,increased apoptosis and suppression of glycolysis,and this regulatory mechanism is closely related with the activation of the downstream AMPK-mTORC1 signaling pathway.

Objective To explore the effects of deletion of protein 4.1R on hepatocyte proliferation,apoptosis,and glycolysis and the molecular mechanisms.Methods A 4.1R-/-HL-7702 cell line was constructed using CRISPR/Cas9 technique,and with 4.1R+/+HL-7702 cells as the control,its proliferative capacity and cell apoptosis were assessed using CCK-8 assay,EdU-488 staining,flow cytometry and Annexin V-FITC/PI staining at 24,48,72 h of cell culture.The changes in glucose uptake,lactate secretion,ATP production and pH value of the culture supernatant of 4.1R-/-HL-7702 cells were determined.The mRNA expressions of the key regulatory enzymes HK2,PFKL,PKM2 and LDHA in glycolysis were detected with qRT-PCR,and the protein expressions of AMPK,p-AMPK,Raptor and p-Raptor were determined using Western blotting.Results Western blotting and sequencing analysis both confirmed the successful construction of 4.1R-/-HL-7702 cell line.Compared with the wild-type cells,4.1R-/-HL-7702 cells exhibited a lowered proliferative activity with increased cell apoptosis.The deletion of protein 4.1R also resulted in significantly decreased glucose uptake,lactate secretion and ATP production of the cells and increased pH value of the cell culture supernatant.qRT-PCR showed significantly decreased mRNA expressions of the key regulatory enzymes in glycolysis in 4.1R-/-HL-7702 cells.Compared with those in HL-7702 cells,the expression levels of AMPK and Raptor proteins were decreased while the expression levels of p-AMPK and p-Raptor proteins increased significantly in 4.1R-/-HL-7702 cells.Conclusion Deletion of protein 4.1R in HL-7702 cells results in reduced proliferative capacity,increased apoptosis and suppression of glycolysis,and this regulatory mechanism is closely related with the activation of the downstream AMPK-mTORC1 signaling pathway.

Objective: Strategy for wound repair of skin and soft tissue defect and systematic rehabilitation treatment for functional reconstruction of patients with severe burn or trauma on knees. Methods: From January 2015 to October 2016, 26 patients with skin and soft tissue defect on knees after severe burn or trauma were hospitalized in our unit. Among these patients, 14 patients had patellar ligament defect, and 16 patients had knee joint capsule defect. Wound debridement was operated on 1 to 3 days after admission. After debridement, the area of skin and soft tissue defect ranged from 10 cm×7 cm to 42 cm×18 cm. Vacuum sealing drainage (VSD) treatment was performed after debridement, and flap transplantation operation was performed after VSD treatment for 5 to 7 days. Defects of nine patients were treated with local rotation flaps. Seven patients with skin and soft tissue defects on knees and knee joint capsule defects of 5 cm×3 cm to 9 cm×7 cm were treated with free anterolateral femoral flaps combined with fascia lata. Ten patients with skin and soft tissue defects on knees and patellar ligament defects of 6 cm×3 cm to 12 cm×4 cm were treated with free anterolateral femoral flaps combined with iliotibial tract. The area of flaps ranged from 11 cm×9 cm to 22 cm×15 cm. After flap transplantation operation, functional reconstruction of knee joint was carried out according to early, continuous, and sequential systematic rehabilitation treatment strategy. The pain degree and function of knee joint of patients were scored by the International Knee Documentation Committee (IKDC) Knee Evaluation Form before operation and 12 months after operation. The knee joint flexion and extension degrees of patients were measured by joint protractor in 2 weeks and 12 months after operation. The color Doppler ultrasound was used to evaluate integrity of knee joint capsule and continuity of patellar ligament of patients in 6 and 12 months after operation. Results: All flaps of 26 patients survived well, and wounds healed completely after the operation. Distal parts of flaps of 2 patients treated with free anterolateral femoral flaps had local necrosis after the operation, and their wounds healed after debridement and transplantation of autologous intermediate split-thickness skin graft of thigh. The IKDC Knee Evaluation Form score of patients was (79±8) points in 12 months after operation, which was significantly higher than (64±7) points before operation (t=7.20, P<0.05). The flexion degree of knee joint of patients was (117±10)° in 12 months after operation, which was significantly larger than (35±8)° in 2 weeks after operation (t=32.65, P<0.05). The extension degree of knee joint of patients was (12±9)° in 12 months after operation, which was significantly smaller than (61±9)° in 2 weeks after operation (t=19.63, P<0.05). In 6 and 12 months after operation, 9 patients treated with local rotation flaps had good integrity of knee joint capsule and continuity of patellar ligament; 7 patients treated with free anterolateral femoral flaps and fascia lata had good integrity of knee joint capsule; 10 patients treated with free anterolateral femoral flaps and iliotibial tract had good continuity of patellar ligament. During follow-up of 12 months, all flaps survived well; knees of all patients had good appearance; knee joints functioned normally. Conclusions Good appearance and function of knees can be achieved by repairing wound of skin and soft tissue defect on knees after severe burn or trauma with local rotation flaps or free anterolateral femoral flaps with fascia lata or iliotibial tract plus systematic rehabilitation treatment of knee joint in early stage after flap transplantation operation.

Objective:To evaluate the effect of goal-oriented online and offline mixed teaching method on the trainees of burn operating room.Methods:From June 2019 to June 2020, 42 trainees of burn operating room in our hospital were selected for the randomized parallel trial, and they were randomly divided into two groups, routine group and research group. The routine group adopted the conventional online and offline mixed teaching method, while the research group adopted the goal-oriented online and offline mixed teaching method. The internship time of both group lasted for 1 month. Results and excellent rates, self-confidence and burn surgery skills evaluation before and after the internship, and satisfaction with the internship mode were compared between the two groups. SPSS 19.0 was used for t test and chi-square test. Results:The results and excellent and good rates of theoretical examination and practical examination in the research group were higher than those of the routine group. The scores of self-confidence, choice of operation mode, innovation and optimization of operation, control of operation complications and treatment of intraoperative emergencies in the two groups after internship were higher than those before internship, and the above scores of research group were higher than those of the routine group after internship. The satisfaction scores of the students on enhancing self-confidence, and improving operational ability, learning initiative and learning efficiency in the research group were significantly higher than those in the routine group ( P < 0.05). Conclusion:Goal-oriented online and offline mixed teaching method on trainees in burn operating room can not only improve the examination results, enhance their confidence and burn surgery skills, but also achieve their satisfaction.

Objective:To explore the feasibility and clinical effects of unilateral superior gluteal artery perforator propeller flap combined with contralateral centripetal advancement flap in repairing huge pressure ulcers in the sacrococcygeal region.Methods:The study was a retrospective observational study. From June 2020 to April 2023, 15 patients with stage Ⅳ pressure ulcers with sacrococcygeal defect area greater than 10.0 cm×10.0 cm who met the inclusion criteria were admitted to the First Affiliated Hospital of Air Force Medical University, including 8 males and 7 females, aged from 30 to 86 years. The pressure ulcers before debridement were all accompanied by different degree of infection and necrosis. Debridement and negative pressure sealing and irrigation treatment were performed in stage Ⅰ. After debridement, the skin and soft tissue defect area was 12.0 cm×10.5 cm to 20.0 cm×17.0 cm. After the wound bed infection was controlled, unilateral superior gluteal artery perforator propeller flap combined with contralateral centripetal advancement flap was used to repair the pressure ulcer wounds in stage Ⅱ. The perforator flap area was 12.0 cm×7.0 cm to 16.0 cm×10.5 cm. The donor area wound was sutured directly. After operation, the survival, complications, and wound healing of flap donor area were observed. During regular follow-up, the recurrence of pressure ulcers, the appearance and texture of the flap, and the scars in the donor site were observed.Results:After operation, 1 patient had fluid accumulation under the flap and survived after drainage and dressing change. The flaps of the other patients survived well without infection, local necrosis, and sinus formation under the flap. The wounds in the donor area healed well. All patients were followed up for more than 6 months, and there was no recurrence of pressure ulcers. The appearance of the flap was not bloated, the texture was soft, and the compression resistance and elasticity were good. The donor site wound healed well without obvious scar.Conclusions:The surgical method of repairing giant sacrococcygeal pressure ulcers with unilateral superior gluteal artery perforator propeller flap combined with contralateral centripetal advancement flap is simple and easy to operate. It can repair large defect area with the donor area being sutured directly, which is worthy of clinical promotion.

The deep tissue defects of extremities are prone to cause the exposure of tendons, blood vessels, nerves, and bones, which are commonly repaired with free flaps in clinical practice. However, for special parts such as fingers, toes, posterior ankles, anterior tibias, and dorsum of feet, the appearances are usually bulky after being repaired with free flaps and need lipectomy operations, which bring great physiological, psychological, and economic burden to patients. As the fascia flap is soft and thin with reliable blood supply and strong anti-infection ability, the free fascia flap combined with skin grafting offers some advantages in repairing the above-mentioned wounds. However, its clinical application is severely limited due to the complexity of surgical operation and the difficulty in observing blood supply after operation. In recent years, our team has carried out a lot of work and accumulated rich experience in repairing deep tissue defects of special parts of extremities with free superficial temporal fascia flap/anterolateral femoral fascial flap combined with skin grafting. From the clinical perspective, this paper mainly introduces the anatomy and harvesting method of free superficial temporal fascia flap/anterolateral femoral fascial flap, as well as the advantages, difficulties, and precautions of clinical application, for reference of peers.