Methyl (S)-4-(6-amino-9H-purin-9-yl)-2-hydroxybutanoate (DZ2002) is a potent reversible inhibitor of S-adenosyl-L-homocysteine hydrolase (SAHH). Due to its ester structure, DZ2002 is rapidly hydrolyzed in rat blood to 4-(6-amino-9H-purin-9-yl)-2-hydroxybutyric acid (DZA) during and after blood sampling from rats; this hampers accurate determination of the circulating DZ2002 and its acid metabolite DZA in rats. To this end, a method for determining the blood concentrations of DZ2002 and DZA in rats was developed by using methanol to immediately deactivate blood carboxylesterases during sampling. The newly developed bioanalytical assay possessed favorable accuracy and precision with lower limit of quantification of 31 nM for DZ2002 and DZA. This validated assay was applied to a rat pharmacokinetic study of DZ2002. After oral administration, DZ2002 was found to be extensively converted into DZA. The level of systemic exposure to DZ2002 was significantly lower than that of DZA. The apparent oral bioavailability of DZ2002 was 90％–159％. The mean terminal half-lives of DZ2002 and DZA were 0.3–0.9 and 1.3–5.1 h, respectively. The sample preparation method illustrated here may be adopted for de-termination of other circulating ester drugs and their acid metabolites in rodents.

Medical imaging technology is a "medicine plus engineering" major,with high practicality.It has characteristics of various courses,professional teaching,and expensive and rapidly-updated special equipments.Current investment in education cannot meet the training teaching requirements for cultivating the talents in medical imaging technology.Therefore,cooperation of school and hospital is necessary.The enrolled student of the five-year higher vocational education is the fresh graduate of junior high school.The practice proves that methods like progressive teaching,theory-practice integration,situational teaching and work-learning integration are suitable for five-year higher vocational education.In our study,the "3.5+0.5+ 0.5+0.5" work-study integration teaching mode in medical imaging technology of five-year higher vocational education is explored.

Objective:To summarize the clinical experience and effect of applying 3D printing assisted with the technology of extracorporeal pre-fenestration in the treatment of thoracic/abdominal aortic aneurysm.Methods:From August 2019 to November 2020, 15 patients with thoracic/abdominal aneurysm involving visceral arteries were admitted to our center, including 11 males and 4 females, with mean age of 57-82(68.26 ±4.73) years old. According to diameters of visceral artery, thoracic aorta, abdominal aorta, and bilateral iliac arteries measured by CTA, we selected suitable stents and made a 3D printing model by professional software to guide the position of intraoperative external fenestration and the fenestration diameter to implement full cavity repair.Results:All operations were completed and one case was converted to laparotomy. The average time of operations was(200.67±41.00)min and hospital stay was(13.47±4.16)days without any death, organ failure, endoleak, paraplegia, graft infection and other complications.Conclusion:The application of 3D printing assisted with the technology of extracorporeal pre-fenestration in the treatment of thoracic/abdominal aortic aneurysm is feasible and effective, and the short-term results are satisfactory.