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Clustered regularly interspaced short palindromic repeats/CRISPR-associated nuclease 9 (CRISPR/Cas9),a cluster of regularly spaced short palindromic repeats,is a natural immune defense system for bacteria and archaea to identify themselves and exogenous invading DNA fragments,protecting them from viruses.In recent years,CRISPR/Cas9 has become a revolutionary gene editing tool.Its specific targeted spot-cutting ability also plays an important role in nucleic acid detection,bacterial typing,etc.,and has shown great application potential in the field of medical testing.Based on the latest researches,this paper reviews the progress of CRISPR/Cas9 application in the new techniques of nucleic acid detection,pathogen typing and bacterial evolution in laboratory medicine,and also summarizes the application prospect of CRISPR technology in the field of laboratory medicine.
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BACKGROUND:It is important to produce and save a large amount of high-activity feeder cel s for the culture of human embryonic stem cel s. OBJECTIVE:To establish the optimal method for isolation and culture of Kunming mouse embryonic fibroblasts, and to evaluate the feasibility of preparing feeder layers for culture of human embryonic stem cel s. METHODS:Embryonic fibroblasts were isolated and cultured by different concentrations of trypsin from Kunming mouse fetuses in vitro. The biological characteristics and growth rule of mouse embryonic fibroblasts were investigated, and then the feeder layers for human embryonic stem cel s culture were produced. The growth of human embryonic stem cel s on the prepared feeder layer was tested. RESULTS AND CONCLUSION:The optimal fetal age for preparing Kunming mouse embryonic fibroblast feeder layer was 13.5 days. Kunming mouse embryonic fibroblasts at different concentrations grew wel with high purity and active proliferation by trypsin digestion method. There was no significant difference in the survival rate of cel s after cryopreservation for 2 weeks, 1 month, 3 months and 6 months. The cel s were proliferative from the second to fourth passage and declined sharply after the fifth passage. Human embryonic stem cel s which grew on Kunming mouse embryonic fibroblasts feeder layers were stil to remain the typical undifferentiated morphology and were strongly positive for alkaline phosphatase and periodic acid-Schiff after long-term subculture. The mouse embryonic fibroblasts can be used as the stable and high-quality feeder cel s for human embryonic stem cel s.
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The clinical ability of employees in laboratory medicine refers to their ability to give useful information and helps for clinical diagnosis and treatment.In laboratory medicine education,the cultivation of the undergraduates'clinical ability should be strengthened.Case teaching and clinical signs analysis is practical to the cultivation of clinical ability.In addition,we should carry out the reform of the teaching materials in order to adapt to the requirements of the clinical ability training. Improving the clinical ability should be the students' a lifelong career planning.
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The article is attempted to introduce PBL teaching in clinical biochemistry. The PBL teaching has improved some aspects of students' abilities in the self-study, accessing to information, solving the problem, teamwork and developing thinking. But in the course of PBL teaching, there are three problems: shortage of qualified teachers, teaching system and students' inability. This article puts forward the countermeasures to resolve these problems.
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Case teaching method was used to undergraduates’specialized courses of clinical laboratory medicine such as the clinical laboratory hemotology and basic clinical laboratory medicine. This teaching method achieved satisfactory effect in clinical ability culture and obtained the positive opinion of students.
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Objective:To investigate the condition of B cell differentiation from cord blood CD34+CD19-hematopoietic stem/progenitor cells in vitro.Methods:CD34+CD19-cells from cord blood were isolated and purified by using immunomagnetic beads separation system.CD34+CD19-cells supported by murine S-17 stromal cells were stimulated in co-culture with T3 and cytokines.Differentiated B cells were analyzed by flow cytometry.Results:The amplification of the B cells derived from CD34+CD19-hematopoietic stem/progenitor cells in co-culture with T3 and IL-7 reached 198-fold of increase,most of the induced cells expressed CD10 and CD19.Conclusion:In the experimental conditions selected,co-culture of CD34+CD19-cells with T3,IL-7 and murine S-17 stromal cells could stimulate differentiate toward to B cells in vitro.