Chinchilla has been successfully used as an animal model in the study of auditory system, microorgan-ism and parasitic infection, because of its unique biological features, and it can be further developed for the research of se-nile diseases, metabolic diseases, etc.This paper will introduce the related biological characteristics of chinchilla, and briefly reviewed the progress of its application in medical research.

Objective:To evaluate the outcomes of posterior-column dominating three-column tibial plateau fractures treated by raft-nailing and cannulated screwing via the posteromedian approach.Methods:From October 2017 to June 2019, 15 patients with posterior-column dominating three-column tibial plateau fracture were surgically treated at Department of Orthopedics, The First Affiliated Hospital to Harbin Medical University. They are 11 males and 4 females, aged from 26 to 65 years (average, 41.2 years). All patients were operated on under general anesthesia or spinal anesthesia. After full exposure via the posteromedian approach using a popliteal S-shaped incision, their fractures were treated with raft-nailing and cannulated screwing. Wound healing and neurovascular injury were observed after operation. X-ray films were taken regularly to monitor fracture union and measure the tibial plateau angle (TPA) and posterior slope angle (PA) of the tibial plateau. The knee function was assessed using The Hospital for Special Surgery (HSS) scoring system at 12 months after operation.Results:Incisions healed by the first intention after surgery in 14 patients but the healing was delayed due to fat liquefaction in one patient. No symptoms of neurovascular injury were observed in the 15 patients who were followed up for 12 to 29 months (average, 16.5 months). All fractures united after 12 to 20 weeks (average, 15.4 weeks). At 3 days and 12 months after operation, respectively, their PA was 9.3°±2.1° and 9.7°±1.6° and their TPA 4.3°±1.2° and 4.1°±1.1°, showing no significant difference ( P>0.05). At 12 months after operation, their HSS scores ranged from 84 to 95 (average, 89.3), their knee flexion from 105° to 138° (average, 126.5°) and their knee extension from 0° to 8° (average, 3.4°). Conclusions:In the treatment of posterior-column dominating three-column tibial plateau fractures, raft-nailing combined with cannulated screwing via the posteromedian approach can achieve not only full exposure by a single incision but also stable plateau fixation, reduce operative invasion, and simplify operative procedures, leading to fine surgical outcomes.

【Objective】 To detect the anti-SARS-CoV-2 antibody levels in blood donors in Guangzhou, so as to provide laboratory data support for the collection and clinical use of convalescent plasma. 【Methods】 Anti-SARS-CoV-2 antibodies were measured by ELISA in qualified donors. Among them, 326 donors who gave blood in February 2023 were tested for IgG antibodies, 444 donors were tested for neutralizing antibodies. In July 2023, 398 donors were tested for IgG and IgM. 【Results】 399 of 724 blood samples diluted with normal saline (1∶160) were IgG reactive, with a reactive rate of 55.11%. Chi-square test showed that there was a significant difference in the reactive rate of IgG among samples collected at different times (25.46% in February vs 79.40% in July, χ²=210.74, P<0.01, 95%CI: 7.97, 15.98), but there was no significant difference in the reactive rate between different genders and different age groups. IgM was detected in 5 of 398 blood samples, with a reactive rate of 1.26%. The IgG test results of these five blood donors were all reactive, whereas the nucleic acid test results were negative. Neutralizing antibody was detected in 440 of 444 blood samples, with a reactive rate of 99.10%, and 71.59% of the reactive donors had a neutralizing antibody level of 10 μg/mL or more. 【Conclusion】 Blood donors in Guangzhou have a high level of SARS-CoV-2 antibody, which is sufficient to provide convalescent plasma for clinical treatment.