Preparation and properties of a new artificial bone composite material / 中国修复重建外科杂志

OBJECTIVE@#To study the preparation and properties of the hyaluronic acid (HA)/α-calcium sulfate hemihydrate (α-CSH)/β-tricalcium phosphate (β-TCP) material (hereinafter referred to as composite material).@*METHODS@#Firstly, the α-CSH was prepared from calcium sulfate dihydrate by hydrothermal method, and the β-TCP was prepared by wet reaction of soluble calcium salt and phosphate. Secondly, the α-CSH and β-TCP were mixed in different proportions (10∶0, 9∶1, 8∶2, 7∶3, 5∶5, and 3∶7), and then mixed with HA solutions with concentrations of 0.1%, 0.25%, 0.5%, 1.0%, and 2.0%, respectively, at a liquid-solid ratio of 0.30 and 0.35 respectively to prepare HA/α-CSH/ β-TCP composite material. The α-CSH/β-TCP composite material prepared with α-CSH, β-TCP, and deionized water was used as the control. The composite material was analyzed by scanning electron microscope, X-ray diffraction analysis, initial/final setting time, degradation, compressive strength, dispersion, injectability, and cytotoxicity.@*RESULTS@#The HA/α-CSH/β-TCP composite material was prepared successfully. The composite material has rough surface, densely packed irregular block particles and strip particles, and microporous structures, with the pore size mainly between 5 and 15 μm. When the content of β-TCP increased, the initial/final setting time of composite material increased, the degradation rate decreased, and the compressive strength showed a trend of first increasing and then weakening; there were significant differences between the composite materials with different α-CSH/β-TCP proportion ( P<0.05). Adding HA improved the injectable property of the composite material, and it showed an increasing trend with the increase of concentration ( P<0.05), but it has no obvious effect on the setting time of composite material ( P>0.05). The cytotoxicity level of HA/α-CSH/β-TCP composite material ranged from 0 to 1, without cytotoxicity.@*CONCLUSION@#The HA/α-CSH/β-TCP composite materials have good biocompatibility. Theoretically, it can meet the clinical needs of bone defect repairing, and may be a new artificial bone material with potential clinical application prospect.

Mechanical Properties of Novel Interlocking Intramedullary Nail for Fixing Transverse Olecranon Fractures / 医用生物力学

Objective To study the effect of interlocking intramedullary nail on fixing transverse olecranon fracture. Methods Nine pairs of fresh ulna specimens were collected and the transverse fracture model of olecranon was established. Kirschner wire tension band and interlocking intramedullary nail were used to repair the fracture. Cyclic dynamic tension loads with amplitude of 25 N, mean value of 45 N and frequency of 05 Hz were applied to the triceps tendon under simulated elbow flexion conditions of 30°, 45° and 60°, respectively. The fracture displacements of specimens within 300 cycles were recorded in three groups. ResultsAt 30° flexion angle, the fracture displacement of interlocking intramedullary nail group and Kirschner wire tension band group was (1.831±0.333) mm and (3.723±2.390) mm, respectively. At 45° flexion angle, the fracture displacement of interlocking intramedullary nail group and Kirschner wire tension band group was (1.167±0.374) mm and (2.455±0.609) mm, respectively. At 60° flexion angle, the fracture displacement of interlocking intramedullary nail group and Kirschner wire tension band group was (1.407±0.342) mm and (3.112±1.025) mm, respectively. The fracture displacement of interlocking intramedullary nail was smaller. Conclusions The mechanical properties of interlocking intramedullary nail are better than those of Kirschner wire tension band, and the interlocking intramedullary nail is more stable and firmer for fixing transverse olecranon fracture. Moreover, the interlocking intramedullary nail is installed with the operating tool, thus the operation is more accurate and faster, and the operation efficiency is greatly improved.

Mechanics Analysis on Novel Micro-Movement Elastic Implant of Distal Tibiofibular Syndesmosis in Dorsiflexion Position / 医用生物力学

Objective To study mechanical properties of the novel micro-movement elastic implant of distal tibiofibular syndesmosis in dorsiflexion position.Methods A combination of simulation and experiment was used. The normal ankle dorsiflexion model, the bone nail repaired model and the micro-movement elastic implant repaired model were established by using Mimics and CT data. Besides, ANSYS Workbench was used for finite element analysis. Mechanical experiments on lower limb specimens were conducted on Instron E10000 mechanical test instrument, and five sets of experimental data were measured and analyzed.Results Mechanical properties of the micro-movement elastic implant repaired model were closer to those of the normal ankle dorsiflexion model, but stress of the micro-movement elastic implant repaired mode was greater than that of the bone nail repaired model. The results of two-sample heteroscedasticity t test indicated that there was no significant difference in resistance torque between the micro-movement elastic implant repaired model and the normal ankle dorsiflexion model.Conclusions For dorsiflexion position, repairing mechanical properties of the novel micro-movement elastic implant are much better than those of the bone nail, and there is still room for optimizing the micro-movement elastic implant.

Clinicopathological features of very well-differentiated adenocarcinoma of the stomach / 中华病理学杂志

Objective: To investigate the clinicopathological features of very well-differentiated adenocarcinoma (VWDA) of the stomach. Methods: The clinicopathological data of 12 cases of VWDA of the stomach were collected retrospectively at the People's Liberation Army Joint Logistics Support Force 989 Hospital (formerly 152 Hospital), Pingdingshan, China, from January 2013 to May 2021. The histological characteristics and immunophenotypes were observed and analyzed with review of current literature. Results: There were 8 males and 4 females with a median age of 63 years (range 47 to 80 years). The tumor involved in the upper part of the stomach in 6 cases, the middle part in 2 cases, and the lower part in 4 cases. The median diameter of the tumors was 17 mm (range 5-65 mm). The tumor cells were similar to absorbent cells, Paneth cells, foveolar epithelial cells, and goblet cells. The cells were arranged in a single layer, and the nuclei were slightly enlarged and located at the base. The nuclei were fusiform to slightly irregular, with loss of nuclear polarity. Early tubular VWDA was found in 9 cases, and the tumor glands were similar to intestinal metaplasia. In two cases the tumors infiltrated into the submucosa. The lesions in the mucosa and submucosa showed the glands with cystic expansion, bending, branching, spiky and abortive growth pattern. One case of early papillary tubular VWDA was confined to the mucosal layer and composed of foveolar-type epithelial cells. There were two cases of advanced papillary tubular VWDA, which consisted of foveolar-type epithelial, pyloric glands, or mucinous neck cells and were associated with intra-lymphatic cancer embolus and lymph node metastases. Background mucosal atrophy and intestinal metaplasia were observed in all cases. Immunohistochemical staining showed intestinal type VWDA in 1 case, mixed gastrointestinal type VWDA in 9 cases, and gastric type VWDA in 2 cases. The Ki-67 proliferation index of 8 cases limited to the mucosa was 40%-70%, 2 cases of infiltration into the submucosa and 2 cases of advanced carcinoma was 10%-25%. All the tumors showed a wild type of p53 protein expression pattern and negative HER2. Adenocarcinoma or high-grade dysplasia was diagnosed on preoperative biopsy in 5 cases, and chronic atrophic gastritis with intestinal metaplasia in 7 cases. The median follow-up time was 28 months (range 12-72 months). No recurrence was found in the 10 patients with early cancer. Of the two patients with advanced carcinoma, one patient had lung metastases and the other died. Conclusions: Gastric VWDA is a rare low-grade malignancy with structural features of highly differentiated adenocarcinoma and extremely low cytological atypia. The diagnostic value of structural abnormality is significantly greater than cytological atypia. The invasive growth of irregular glands in the deep mucosa and submucosa is reliable evidence for diagnosis. The diagnosis of intramucosal VWDA is challenging and very difficult in some biopsy specimens.

Axial Mechanical Properties of the Posterior Spinal Pedicle Fixation System / 医用生物力学

Objective To analyze factors that affect axial mechanical performance of the posterior pedicle fixation system. Methods The mechanical model for axial mechanical properties of the posterior pedicle fixation system was established to perform mechanical analysis. By referring to the Standard YY/T 0961-2014, tests on axial ejection force and axial clamping torque of JHL-I multi-axis components, JHL-I single-axis components, JHL-V multi-axis components and JHL-V single-axis components were performed by using Instron E3000 and Instron E10000 mechanical testing machines. Results The ejection rigidity of the single-axis component of vertebral nail system was significantly higher than that of the multi-axis component of vertebral nail system; the torsion rigidity of JHL-V was higher than that of JHL-I. The type and size of the locking bolt as well as its locking torque were the main factors affecting axial ejection force of the posterior spinal pedicle fixation system; the size of the locking bolt and the diameter of the connection rod were the main factors affecting axial clamping torque of the system; axial mechanical properties of the system could be improved by increasing the diameter of the connecting rod, the coefficient of friction between each connecting element, and the pitch diameter of the locking bolt. Conclusions The research findings provide references for optimizing and improving axial mechanical properties of the posterior pedicle fixation system.

Introduction of intervention programs on cyberbullying abroad / 中国学校卫生

Abstract@#With the growing popularity of electronic devices, cyberbullying has gradually become a common form of bullying. Compared with traditional bullying, cyberbullying is more likely to cause serious psychological problems of its victims, leading to school absences, depression, even selfinflicted injury and suicide. Unfortunately, psychological intervention and prevention for cyberbullying and cyber victimization is rather sparse in China. This paper summarizes some foreign cyberbullying intervention projects, aiming at providing reference localized and specific interventions.

Inhibitory effects of Pin1 silencing by siRNA on apoptosis of H9c2 cardiomyo-cytes induced by hypoxia/reoxygenation / 中国免疫学杂志

Objective:Pin1 plays an important role in the pathogenesis of cardiovascular disease,our study aims to investigate the effects of Pin1 silencing by siRNA on H9c2 apoptosis induced by hypoxia/reoxygenation.Methods:H9c2 cells were cultured and subjected to a hypoxia/reoxygenation (H/R) condition in vitro,mimicking ischemic/reperfusion injury in vivo.The mRNA and protein expression of Pin1 were detected by RT-qPCR and Western blot.H9c2 cells were divided into control group,H/R group,H/R+Pin1 siRNA group,H/R+scramble siRNA group.MTT and flow cytometry with Annexin V-FITC/PI staining were respectively performed to detect cell viability and apoptosis.The expression of Bax and Bcl-2 were measured by Western blot.The activity of Caspase-3 was detected by automatic biochemistry analytic instrument.Results:The mRNA and protein levels of Pin1 were highly expressed in the cells of H/R group.Transfection with Pin1 siRNA strikingly inhibited the expression of Pin1.Compared with H/R group,Pin1 siRNA markedly increased cell viability,decreased the cell apoptosis and the Caspase-3 activity.Furthermore,the increased Bcl-2,decreased Bax and the ratio of Bcl-2 to Bax were observed in Pin1 siRNA group (P<0.05) compared with H/R group.Conclusion:Downregulation of Pin1 protects hypoxia/reoxygenation-injured H9c2 cells from apoptosis,which is possibly through the upregulation of Bcl-2 and downregulation of Bax and Caspase-3 activity.