BACKGROUND: An ideal marked molecule has not been found to detarmine bone marrow mesenchymal stem cells (MSCs) so as to make sure the homogenicity.OBJECTIVE: To verify the in vitro differentiation from BrdU-treced MSCs into osteoblasts.DESIGN, TIME AND SETTING: A cytological observation/n vitro was performed in Shanxi Medical University from January to October 2008.MATERIALS: Wistar rats aging 4 weeks old were provided by Experimental Animal Center of Shanxi Medical University.METHODS: MSCs were isolated and cultured by using density gradient cantrifugation combined with attachment culture method.At about 80% confluence, trypsin was used for passage and amplification. MSCs at density of 5×1010/L were inoculated in a 25-mm culture dish with L-DMDM culture medium containing dexamethasone, β -phosphoglycarol, vitamin C, and 10% fetal bovine serum. The third-passaged MSCs were labeled in vitro with 10 μmol/L BrdU tracer. Thereafter, 10 visual fields were randomly selected to calculate numbers of positive and negative ceils so as to obtain BrdU tracing rate under a fluorescence microscope (×200).MAIN OUTCOME MEASURES: Inverted microscope was used to observe cell morphology; flow cytometry was used to detect cell surface antigen, differentiation into osteoblasts, and BrdU tracing rate in vitro.RESULTS: The purified MSCs which were like fibroblasts were adherent and fusiform. The third-passaged cells were changed equidirectionally and whirlpool-arranged, and the survival rate was more than 95%. The seventh-passaged cells still grew rapidly.CD44, CD71, and CD105 expressions were positive, but CD45 expression was negative. Black particles were visualized in MSCs after Von kossa staining. BrdU tracing rate was more than 90%.CONCLUSION: Density gradient centrifugation combined with attachment culture method can effectively isolate and purify rat MSCs which are cultured in vitro for a long period and differentiated into osteoblasts. BrdU tracer is safe, effective, and convenient to successfully label MSCs.

As the special subject of the applicant for registration of medical device, the research and development institutions have insufficient conditions and abilities to become medical device registrants, and there are certain difficulties in the actual registration application process, such as not clearing the certification path for the research and development institutions to hold the certificate. In view of the existing problems, by comparing the path of medicine research and development institutions to become medical device registrants and combining with the actual medical device industry to give relevant suggestions, including improving quality management over the whole life cycle of medical devices, quality and safety responsibility ability of research and development institutions, establishing the registration and certification path of research and development institutions, supporting laws and regulations, etc., so as to ensure that the research and development institutions become medical device registrants successfully.
Research ; Certification

Plastic surgery is characterized by high degree of specialization, a broadscope of diseases inclusion and rapid advancements in knowledge. It is closely related to many disciplines, and there is great heterogeneity among different patients, which requires comprehensive abilities of doctors. However, plastic surgery teaching in China is currently marked by a short training cycle, a uniform training mode, and students’ time constraints and heavy tasks. Chat generative pre-trained transformer (ChatGPT), a large-scale language model introduced by the artificial intelligence company OpenAI, can use deep learning technology to generate natural language texts, understand the context of a conversation and then generate responses similar to those of humans, and is widely used in various industries, including the medical field. This review began by identifying the current challenges in plastic surgery teaching, introduced potential applications of ChatGPT in the field, and outlined its advantages. It also discussed the limitations and potential future directions for its development.

Plastic surgery is characterized by high degree of specialization, a broadscope of diseases inclusion and rapid advancements in knowledge. It is closely related to many disciplines, and there is great heterogeneity among different patients, which requires comprehensive abilities of doctors. However, plastic surgery teaching in China is currently marked by a short training cycle, a uniform training mode, and students’ time constraints and heavy tasks. Chat generative pre-trained transformer (ChatGPT), a large-scale language model introduced by the artificial intelligence company OpenAI, can use deep learning technology to generate natural language texts, understand the context of a conversation and then generate responses similar to those of humans, and is widely used in various industries, including the medical field. This review began by identifying the current challenges in plastic surgery teaching, introduced potential applications of ChatGPT in the field, and outlined its advantages. It also discussed the limitations and potential future directions for its development.

Emergence of the colistin resistance gene,mcr-1,has attracted worldwide attention.Despite the prevalence of mcr-1-positive Escherichia coli(MCRPEC)strains in human carriage showing a significant decrease between 2016 and 2019,genetic differences in MCRPEC strains remain largely unknown.We therefore conducted a comparative genomic study on MCRPEC strains from fecal samples of healthy human subjects in 2016 and 2019.We identified three major differences in MCRPEC strains between these two time points.First,the insertion sequenceISApll1 was often deleted and the percentage of mcr-1-carrying IncI2 plasmids was increased in MCRPEC strains in 2019.Second,the antibiotic resistance genes(ARGs),aac(3)-Ⅳa and blaCTX-M-1,emerged and coexisted with mcr-1 in 2019.Third,MCRPEC strains in 2019 contained more viru-lence genes,resulting in an increased proportion of extraintestinal pathogenic E.coli(ExPEC)strains(36.1％)in MCRPEC strains in 2019 compared to that in 2016(10.5％),implying that these strains could occupy intestinal ecological niches by competing with other commensal bacteria.Our results suggest that despite the significant reduction in the prevalence of MCRPEC strains in humans from 2016 to 2019,MCRPEC exhibits increased resistance to other clinically important ARGs and contains more virulence genes,which may pose a potential public health threat.

OBJECTIVE: To study the effect of aquaporin 4(AQP4) in regulating the permeability of blood-brain barrier(BBB) induced by subacute 1,2-dichloroethane(1,2-DCE) inhalation. METHODS: Specific pathogen free healthy CD-1 male Aqp4 genetically engineered mice(Aqp4~(+/+)and Aqp4~(-/-)) were randomly divided into control and low-, medium-and high-dose groups. The mice were exposed to 1,2-DCE at the dosages of 0.00, 100.00, 350.00 and 700.00 mg/m~3 for 6 hours per day for consecutive 28 days by systemic dynamic inhalation. After the end of 1,2-DCE exposure, the BBB permeability was evaluated by Evans blue staining. Real-time fluorescence quantitative polymerase chain reaction method was used to detect the mRNA expression of genes related to BBB tight junction protein(Tjp)1, Tjp2, Tjp3, claudin(Cldn)3, Cldn5, Cldn11, occludin(Ocln), matrix metalloproteinase(Mmp)2, Mmp9 and Na-K-Cl cotransporter-1(Nkcc1). RESULTS: The BBB permeability in mice showed significant change with 1,2-DCE dose and Aqp4 genotype(P<0.01). The BBB permeability of Aqp4~(+/+) genotype mice was higher in low-, medium-and high-dose groups than that of control group(all P values were <0.05). The permeability of BBB was lower in Aqp4~(+/+) genotype mice in the control group than that of Aqp4~(-/-) genotype mice in the same group(P<0.05), but BBB permeability was higher in Aqp4~(+/+) genotype mice in the three dose groups than that of Aqp4~(-/-) genotype mice in the same group(all P values were <0.05). The Cldn3 and Olcn mRNA relative expression in the brain cortex had statistical difference in mice with different genotype(all P values were <0.01). The mRNA relative expressions of Cldn3 and Olcn in the brain cortex were higher in Aqp4~(-/-) genotype mice than that of Aqp4~(+/+) genotype mice(all P values were <0.01). The relative mRNA expression levels of Tjp1, Tjp2, Tjp3, Cldn5, Cldn11, Mmp2, Mmp9 and Nkcc1 in the cerebral cortex of mice were not statistically significant in aspect of 1,2-DCE exposure dose and genotype(all P values were >0.05). CONCLUSION: Exposure to 1,2-DCE can increase BBB permeability in mice, and the mechanism may be associated with 1,2-DCE-induced down-regulation of Aqp4 and up-regulation of mRNA expression of the cerebral cortex TJP-related molecules Cldn3 and Ocln.

Genetically engineered intestinal microbes could be powerful tools to detect and treat intestine inflammation due to their non-invasive character, low costs, and convenience. Intestinal inflammation is usually detected along with an increasing concentration of thiosulfate and tetrathionate molecules in the intestines. ThsSR and TtrSR are two-component biosensors to detect the presence of thiosulfate and tetrathionate molecules, respectively. In real-life intestinal inflammation detection, sophisticated instruments are needed if using fluorescent proteins as reporters. However, chromoproteins and other colored small molecules, which can be seen by the unaided eye, could extend the use of ThsSR and TtrSR biosensors to detect intestine inflammation. The feasibility of ThsSR and TtrSR systems was tested by monitoring the fluorescence intensity of sfGFP in response to the concentration of thiosulfate and tetrathionate, followed by the incorporation of the two systems into Escherichia coli Top10 and E. coli Nissle 1917. The potential for the real-life application of the two systems was further corroborated by substituting sfGFP with a series of chromoproteins and a protoviolaceinic acid synthesis cassette as reporter genes. The results indicated that signal expression of the new systems had a positive correlation with the concentration of tetrathionate and thiosulfate molecules. Thus, the modified ThsSR and TtrSR system may potentially be applied in the human body for the detection of intestinal inflammation.
Escherichia coli ; Humans ; Inflammatory Bowel Diseases ; Intestines ; Thiosulfates

ObjectiveTo investigate the effect of intermittent theta burst stimulation (iTBS) of the multi-target cerebral cortex after stroke on functional recovery of the upper limb of the hemiplegic side. MethodsFrom November, 2019 to August, 2020, 40 stroke patients in Gansu Provine Hospital Rehabilitation Center were included and randomly divided into single-target stimulation group (n = 20) and multiple-target stimulation group (n = 20). Both groups underwent basic neurorehabilitation drug therapy and conventional rehabilitation exercises. The single-target stimulation group received repetitive transcranial magnetic stimulation (rTMS) (iTBS mode) only in the primary motor cortex (M1) of the affected side. The multi-target stimulation group received rTMS (iTBS mode) in the cerebellar cortex of the healthy brain and M1 of the affected side, once a day, six days a week, for four weeks. Before and after treatment, the scores of Fugl-Meyer Assessment-Upper Extremities (FMA-UE), Action Research Arm Test (ARAT) and modified Barthel Index (MBI), and the latency and amplitude of somatosensory-evoked potentials N20 were compared. ResultsNo serious adverse reaction occurred during treatment. After treatment, the scores of FMA-UE, MBI and ARAT, and the amplitude and latency of N20 improved in both groups (|t| > 3.478, |Z| > 2.243, P < 0.05); and the scores of FMA-UE and ARAT, and the amplitude of N20 were better in the multiple-target stimulation group than in the single-target stimulation group (t > 2.939, Z = -2.697, P < 0.01). ConclusionMulti-target stimulation is superior to single-target stimulation for improving upper limb motor function and N20 amplitude in the hemiplegics after stroke.

OBJECTIVE: To investigate the effect and mechanism of lead exposure on hypothalamic inflammatory factors in mice fed with high-fat diet. METHODS: Specific pathogen free healthy male Kunming mice were randomly divided into control group, high-fat diet group, lead exposure group, and combined exposure group, with 8 rats in each group. The control group and the lead exposure group were given regular diet, while high-fat diet group and combined exposure group were given high-fat diet. The lead exposure group and combined exposure group were given water with 250 mg/L lead acetate. The control group and high-fat diet group were given double distilled water. Continuous lead exposure was given for 9 weeks, 7 days per week. Body weights of the mice were measured every other week. After 9 weeks of exposure, the behavioral changes of mice were detected by open field test. The levels of triglyceride(TG), low density lipoprotein(LDL) and high density lipoprotein(HDL) in serum were detected by microplate reader. Western blotting was used to detect the relative protein expression of interleukin(IL)-1β, IL-6, IL-17 A, IL-22, tumor necrosis factor-α(TNF-α) and transforming growth factor-β(TGF-β) in the hypothalamus of mice. The relative expression of mRNA of IL-1β, IL-6, IL-17 A and TNF-α mRNA was detected by real-time fluorescence quantitative polymerase chain reaction. RESULTS: Beginning from the first week, the body weights of mice in the high-fat diet group and the combined exposure group were higher than that in the control group and the lead exposure group(P<0.05). The numbers of standing in the lead exposure group and the combined exposure group were lower than that in the control group and the high-fat diet group(P<0.05). The distances of central area activity in the high-fat diet group, the lead exposure group and the combined exposure group were lower than that in the control group(P<0.05). The total distances in the high-fat diet group and the combined exposure group were lower than that in the control group(P<0.05). The serum levels of TG and LDL in the combined exposure group increased(P<0.05), and the HDL level decreased(P<0.05), when compared with the control group and the lead exposure group. The relative protein expression of IL-1β, IL-6, IL-17 A and IL-22 in the hypothalamus of the high-fat diet group and lead exposure group was higher than those of the control group(P<0.05). The relative protein expression of TNF-α and TGF-β in the hypothalamus of the lead exposure group was higher than that in the control group(P<0.05). The relative protein expression of IL-1β, IL-6, IL-17 A, TGF-β in the hypothalamus of the combined exposure group was higher than the other 3 groups(P<0.05). The relative protein expression of IL-22 in the hypothalamus of the combined exposure group was higher than that of the control group(P<0.05), while the relative protein expression of TNF-α was higher than that of the control group and the high-fat diet group(P<0.05). The relative expression of IL-1β, IL-6, IL-17 A, and TNF-α mRNA in the hypothalamus of the high-fat diet group, the lead exposure group and the combined exposure group was higher than that in the control group(P<0.05). The above indicators of mice in the lead exposure group were higher than that in the high-fat diet group(P<0.05). The above indicators of mice in the combined exposure group were higher than those in the high-fat diet group and the lead exposure group(P<0.05). CONCLUSION: Lead exposure can promote neurobehavioral changes and hypothalamic inflammatory damage in high-fat diet mice. IL-1β, IL-6, IL-17 A, TGF-β and TNF-α might involve in the process of synergistic effect of lead and high-fat diet exposure on inflammatory hypothalamic injury.