Objective:To study the effects of ascorbic acid on BMP-2 mRNA expression of osteoblast cell sheets.Methods:Rat os-teoblasts were primaryly cultured and identified;osteoblast cell sheets were built by physical scraping method in vitro;the osteoblast cell sheets were cultured with 1 5,50 and 85 mg/L ascorbic acid for 1 and 2 weeks respectively,and the expression of BMP-2 mRNA of the cell sheets was detected by RT-qPCR.Results:The obtained cells were conformed to be osteoblasts.The osteoblast cell sheets could be rolled into tube in vitro.The expression of BMP-2 mRNA of osteoblast cell sheets in experiment group,whether in week one or week two was higher than that in control group,50 mg/L group showed the highest expression(first week P <0.05;second week P>0.05);the expression of any group in week two was higher than that in week one(P <0.05).Conclusion:Ascorbic acid may pro-mote the expression of BMP-2 mRNA in osteoblast cell sheets.

OBJECTIVE:To optimize the extraction technology of asiaticosides from Centella asiatica. METHODS:Using to-tal amounts of asiaticoside and hydroxy asiaticoside as investigation indexes,single factor and orthogonal test were used to investi-gate the enzyme amount,enzymolysis time,enzymolysis temperature,ethanol volume fraction,liquid material ratio and ultrasonic extraction time and optimize the extraction technology of asiaticosides from C. asiatica by ultrasonic-enzyme method,and verifica-tion test was conducted. RESULTS:Optimal extraction technology was as follow as cellulose dosage of 12 mg/g,10-fold liquid ma-terial ratio added into 60% ethanol,enzyme hydrolysis for 60 min at 60 ℃,ultrasonic assisted extraction for 50 min. Average ex-traction rate of total asiaticosides was 1.92%(RSD=1.83%,n=3)in verification test. CONCLUSIONS:Ultrasonic-enzyme meth-od is stable and feasible for the extraction technology of asiaticosides from C. asiatica.

Objective To determine the electrocardiographic (ECG) characteristics of myocardial infarction (MI) evolution in rats and the intervention effect of Chinese herbs, and to provide basis for the establishment of the criteria for ECG diagnosis and assessment of drug therapeutic effects of rats MI. Methods Totally 140 male SD rats were randomly divided into sham operation group, model group, replenishing qi group, activating blood group, replenishing qi and activating blood (1∶2) and (2∶1) group as well as Tongxinluo group, each group with 20 rats. The rat MI model was established by ligating the left anterior descending coronary artery. The treatment groups were administrered with corresponding drugs by gavage from the first day after operation. The sham operation group and model group were given the same volume of distilled water. The 12-lead ECGs were recorded before, immediately after, 1st and 2nd week after operation respectively. The voltage value of ST segment deviation, the time limit of QRS complex and the number of animals with pathologic Q wave were evaluated for statistical analysis. Results Model group showed the elevation of ST segment, significantly prolonged time limit of QRS complex (P<0.01), and no pathologic Q wave showed immediately after operation compared with sham operation group. And all above observational indexes reached the peak at 1st week and declined at 2nd week after operation. Compared with model group at 2nd week after operation, replenishing qi and activating blood (1∶2) group and (2∶1) group all presented remarkable dropping of ST segment, shortening in time limit of QRS complex and reduction in number of rats with pathologic Q wave, of which 2∶1 group showed the most (P<0.01). Activating blood group only displayed decreases in time limit of QRS and number of rats with pathologic Q wave (P<0.05), and no significant decline in ST segment. Replenishing qi group demonstrated no significant changes in above three observational indexes (P>0.05). Thus, we proposed the criterion for the ECG diagnosis of rats MI as well as the criterion for the ECG assessment of drug therapeutic effects of rats MI. Conclusion ECG can overall and sensitively evaluate the evolution and drug therapeutic effects of MI in rats, thus providing a relatively objective and available assessment method for the experimental studies of myocardial ischemic diseases.

Objective:To characterize the severe sports injuries related to alpine skiing during the 2022 Beijing Winter Olympics and Paralympics so as to provide information for the prevention and treatment of sports injuries in the Yanqing National Alpine Skiing Center tracks.Methods:The medical data were collected of all the alpine skiing athletes and related staff who had sought medical treatment in Peking University Third Hospital Yanqing Hospital during January 20, 2022 to March 26, 2022. Descriptive statistical analyses were conducted for body part, type, occurrence place, and severity of the injuries.Results:There were 49 patients who had suffered severe injuries related to alpine skiing events during this Olympic Games, with 68 injuries by body parts and 72 injuries by types. The most common injury part was the knee (25.0%, 17/68), followed by the head (14.7%, 10/68), and the shoulder (8.8%, 6/68). The most common types of injury were contusion (including hematoma and abrasion, 30.6%, 22/72), followed by sprain (including dislocation, subluxation, and ligament injury, 22.2%, 16/72), and fracture (20.8%, 15/72). The most common occurrence place in the tracks for athletes was the "Haituo Bowl" area (41.7%, 10/24). In terms of severity, the injuries led to an absence from training or competition in 48 athletes [98.0% (48/49)], of whom 33 were severely injured [67.3% (33/49)].Conclusions:The most vulnerable part for severe sports injuries in the alpine skiing events of the 2022 Beijing Winter Olympics and Paralympics was the knee, mostly with ligament injuries, which is consistent with the findings of previous events. The high proportion of severe injuries indicated the difficulty of this track. The place where injuries mostly occurred was the "Haituo Bowl" area of the racing track, also the most challenging part of this track, indicating a necessity of more medical resources in this area.