Objective To evaluate the dynamic contrast-enhanced MRI (DCE-MRI)in detecting experimentally induced testicular ischemia. Methods Thirty healthy male New Zealand rabbits were randomly assigned into 6 groups. There were 5 rabbits in each of the following experimental groups: ( 1 ) Normal control, (2) Sham-operated, (3) ischemia of 3 h group, (4) ischemia of 6 h group, (5) ischemia of 12 h group, (6) ischemia of 24 h group. In all experiment groups, the right testis served as the internal control while the left testis served as the experimental side. DCE-MRI for each animal lasts about 10 minutes. Signal enhanced ratios (SERs) of ROI for both sides of each group were calculated by a computer, and parameters of SERs of 30 s, 75 s, 120 s and maximal SER were used for statistical analysis.Time intensity curves (TICs) were made for two sides of each group via Excel 2003 software and classified into 4 types. Statistical analysis was performed to compare the differences of SERs between left and right testis by two independent Kolmogorov-Smirnov test. Results In group I and 2, significant enhancement was observed on both testes of 10 rabbits. The enhancement decreased gradually with the elongation of ischemia in torsion groups. Three cases of type Ⅰ and 2 cases of type Ⅱ were observed in group 1,5 cases of type Ⅰ in group two, 2 cases of type Ⅰ and 3 cases of type Ⅱ b in group three, 2 cases of type Ⅰ and 2 cases of type Ⅱ b in group four, 5 cases of type Ⅱ b in group five and 5 cases of type Ⅲ in group six were noticed in the left testes. And in TICs of right testes, all cases showed TICs of type Ⅰ except 2 cases of type Ⅱ a in group six. In four torsion groups, the values for SER75 of the left side were 0. 084%, 0. 076%, 0.164% and 0.065%, while the right side were 0.255%, 0.410%, 0.586% and 0.302% (P ＜0.05). The values for SER120 in group three, five and six were 0.221% , 0.158% and 0.059% for the left side, and 0.405%,0.522% and 0.207% for the right side(P ＜0.05). The values for MSER in group three, five and six were 0.217% ,0.164% and 0.072% for the left side, and 0.405%, 0.586% and 0.302% for the right side(P ＜0.05). Conclusion DCE-MRI technique may be useful in the diagnosis of testicular torsion, which shows potential in the clinical application.

Ischemic stroke is a cerebrovascular disease with high disability rate and mortality. At present,there is no effective treatment to promote the recovery of neurological function after ischemic stroke. Exosomes can not only mediate the communication between cells,but also have the ability to cross the blood-brain barrier,so they have received extensive attention in the treatment of ischemic stroke. Exosomes are modified by bioengineering technologies to prepare engineered exosomes with brain targeting and therapeutic effects,which have been applied in the research and treatment of ischemic stroke,in order to improve the repair of neurological function after stroke,reduce the clinical disability rate and mortality,and improve the survival and quality of life of patients. This article reviews exosomes,the role of exosomes in ischemic stroke,and the preparation of engineered exosomes,and discusses the application prospect of engineered exosomes in the treatment of ischemic stroke,with a view to providing a reference for subsequent research.

Traditional Chinese Medicine (TCM) has certain advantages in the treatment of precancerous lesions of gastric cancer (PLGC) based on the holistic concept and the thought of syndrome differentiation. Currently, it is generally divided into 6 kinds of syndromes: liver and stomach qi stagnation syndrome, liver and stomach heat stagnation syndrome, spleen and stomach weakness syndrome (including spleen and stomach qi deficiency syndrome with coldness), spleen and stomach damp heat syndrome, stomach yin deficiency syndrome and blood stasis in stomach collateral syndrome. Clinically, the doctor should treat PLGC patients according to different syndrome types by using Chinese medicine prescription, which could improve the gastric mucosal pathological state, gastroscopy and clinical symptoms, to rehibit the development of precancerous lesions, reduce the incidence rate of gastric cancer. In the future, the doctors shouldreach the consensus of treating PLGC with TCM diagnosis, and focus on the research of TCM compounds or monomers with obvious curative effect, increase the times of follow-up, and evaluate the long-term curative effect.

Parkinson's disease (PD) is one of the hotspots in the research field of neurodegenerative diseases, and its pathogenesis is still controversial. Trace metal elements play an important role in normal growth and development of the human body. Metal ions can cross the blood-brain barrier and enter the brain, leading to α-synapnuclein aggregation, mitochondrial dysfunction, and degeneration of dopaminergic neurons, and then inducing the occurrence of PD. This article mainly reviewed the potential mechanisms of metal elements in PD, discussed the role of metabolic imbalance of common trace metals (copper, iron, manganese, and zinc) in PD, and put forward new insights into the treatment of PD.

Objective: This ex vivo study evaluated the effect of ultrasound and Er:YAG laser irrigation activation techniques on the penetration of sodium hypochlorite solution into infected human root canal dentin, providing a reference for clinical infection control of infected root canals. Methods : Thirty-six cases of infected root canals were collected and randomly divided into three groups according to the irrigation technique: 12 cases in the conventional syringe irrigation (CSI) group, 12 cases in the passive ultrasonic irrigation (PUI) group, 12 cases in the Er:YAG laser and photon-induced photoacoustic streaming (PIPS) group and 36 cases of clean root canals (12 cases in the CSI group, 12 cases in the PUI group, 12 cases in the PIPS group). All of the selected root canals were straight root canals of posterior teeth. After standardizing the root length, all canals were subjected to instrumentation and dynamic irrigation. 2% methylene blue solution was used to visualize the penetration of the irrigant. EXAKT cutting and grinding equipment was used to take transverse sections of 100-150 μm at the coronal, middle and apical thirds of the root canals. The data (maximum penetration depth, average penetration depth, and penetration percentage) were observed under a light microscope to evaluate the effect of dye penetration. Results : With the three irrigation techniques, the maximum penetration depth, average penetration depth and penetration percentage of the infected root canals were significantly lower than those of clean root canals in the full length of the root canal (P<0.05). The penetration percentage, average penetration depth and maximum penetration depth of the PIPS group were significantly higher than those of the CSI group in the coronal, middle and apical thirds of the infected root canal, respectively (P<0.05). There was no significant difference in the maximum penetration depth, average penetration depth or penetration percentage between the PUI and CSI groups (P>0.05). There was also no significant difference in the maximum penetration depth, average penetration depth or penetration percentage between the PIPS and PUI groups (P>0.05). Conclusion The dentine permeability of infected root canals was weaker than that of clean root canals. Er:YAG laser-assisted irrigation activation technology could significantly improve the penetration of sodium hypochlorite solution into infected dentin, but passive ultrasonic irrigation did not significantly improve the penetration.