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BACKGROUND: Systemic lupus erythematosus is an autoimmune disease with unknown causes. To establish a tree shrew model of systemic lupus erythematosus is helpful to understand its pathogenesis and provide evidence for stem cell transplantation in the treatment of autoimmune diseases. OBJECTIVE: To establish a tree shrew model of systemic lupus erythematosus and to assess the therapeutic effect of umbilical cord mesenchymal stem cell transplantation. METHODS: Tree shrews were grouped and intraperitoneally injected pristane, lipopolysaccharide, and their combination. At 3 weeks after injection, 12 tree shrew models were divided into treatment group and model control group (n=6 per group). An additional 6 models were selected as a normal control group. In the treatment group, each tree shrew was injected with 1×106 DiR-labeled umbilical cord mesenchymal stem cells through caudal vein. Two weeks later, the heart, liver, spleen, lung and kidney of tree shrews were taken for pathological sections. The sections received hematoxylin-eosin staining, kidney Masson staining and immune complex detection. Simultaneously, the heart, liver, spleen, lung and kidney of the three groups of tree shrews were taken for in vitro imaging. RESULTS AND CONCLUSION: (1) Hematoxylin-eosin staining showed pathological changes of the heart, liver, spleen, lung and kidney in the model control group; and there were a lot of immune complex deposits in renal tissue in the model control group. The pathological changes in the treatment group improved, and the structure recovered to close to the normal control group. (2) In vitro imaging showed that DiR-labeled cells were mainly distributed in the lung, liver and spleen of the tree shrews in the treatment group. The fluorescence intensity of tree shrews in the treatment group was significantly higher than that in the normal control group and model control group (P < 0.05). (3) Results demonstrated that intraperitoneal injection of pristane and lipopolysaccharide is the best method to induce pathological changes of systemic lupus erythematosus in tree shrews. The pathological changes after treatment with umbilical cord mesenchymal stem cells have improved, indicating that umbilical cord mesenchymal stem cells have certain treatment effects on tree shrew models of systemic lupus erythematosus.
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BACKGROUND: Current treatments for metabolic syndrome are comprehensive treatments with drugs, aiming to improve patient’s life. Patients are required to have a high compliance to follow-up and have developed various adverse reactions. Therefore, there is no treatment to fundamentally delay the development of metabolic syndrome. OBJECTIVE: To establish a tree shrew model of metabolic syndrome and evaluation techniques, and to explore the therapeutic effect of umbilical cord mesenchymal stem cells in the tree shrew model, providing theoretical basis and reference method for clinical application of stem cell transplantation in metabolic syndromes. METHODS: Umbilical cord mesenchymal stem cells of tree shrews were obtained by adherent culture method, and met the biological characteristics of umbilical cord mesenchymal stem cells. The dark red fluorescent iodide DIR was used to label tree umbilical cord mesenchymal stem cells. Thirty-two tree shrews were fed high-sugar, high-cholesterol, high-salt diet and syrup diet, and injected streptozotocin to make metabolic syndrome models. Animal models were randomly divided into model control group (n=10) and cell treatment group (n=22). In the cell treatment group, the umbilical cord mesenchymal stem cells labeled in vitro were injected into the tail vein, and the model group was injected an equal volume of physiological saline in the meanwhile. Blood biochemical indicators, glucose tolerance, insulin resistance index and arterial blood pressure were measured after transplantation. RESULTS AND CONCLUSION: The tree shrew model of metabolic syndrome was successfully constructed, showing obvious insulin resistance, hyperglycemia, lipid metabolism disorder, and hypertension, which met the diagnostic criteria of metabolic syndrome. Umbilical cord mesenchymal stem cells transplantation could significantly reduce the blood glucose and blood lipid levels, improve insulin resistance and regulate insulin secretion in the tree shrew model of metabolic syndrome. Transplanted umbilical cord mesenchymal stem cells could be homing to the liver, kidney and pancreas of the tree shrew model of metabolic syndrome, and produce certain repairing effects.
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BACKGROUND: Studies have shown that umbilical cord mesenchymal stem cells are ideal seed cells for tissueengineering research.OBJECTIVE: To isolate, culture and identify tree shrew umbilical cord mesenchymal stem cells, in order toestablish a standardized tree shrew umbilical cord mesenchymal stem cell lines.METHODS: Caesarean-isolated tree shrew umbilical cord samples were used to isolate and culture umbilical cordmesenchymal stem cells using tissue explant adherent method. Flow cytometry assay was used to detect cellsurface markers. Osteogenic and adipogenic induction media were used to induce umbilical cord mesenchymalstem cells to differentiate into osteoblasts and adipocytes.RESULTS AND CONCLUSION: The cultured umbilical cord mesenchymal stem cells expressed CD90 and CD105 with the positive rate of 99.9% and 99.8% respectively. Hematopoietic stem cell marker CD34 expression ratewas 0.0% and the endothelial cell marker CD31 expression rate was 0.7%, in line with the characteristics of umbilicalcord mesenchymal stem cell surface markers. Calcium nodules by alizarin red staining and lipid droplets by oil red Ostaining were observed in the induced cells. These experimental findings indicated that umbilical cord mesenchymalstem cells from tree shrews capable of osteogenic and adipogenic differentiation were successfully isolated and cultured.
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BACKGROUND:Systemic lupus erythematosus is an autoimmune disease characterized as an emergence of a variety of autoantibodies in serum and multi-system and multi-organ lesions. Currently, there is a lack of effective treatment options, and umbilical cord mesenchymal stem cel s are a promising therapy for systemic lupus erythematosus based on cel biological roles. OBJECTIVE:To observe the therapeutic efficacy of human umbilical cord mesenchymal stem cel transplantation in the treatment of systemic lupus erythematosus in mice. METHODS:Human umbilical cord mesenchymal stem cel s were isolated and cultured fol owed by labeling with DiR fluorescence. Experimental mice were divided into normal control group (C57BL mice), model control group (C57BL/lpr mice), low-, medium-and high-dose umbilical cord mesenchymal stem cel therapy groups (C57BL/lpr mice), with 10 mice in each group. Mice in the low-, medium-and high-dose groups were respectively injected 0.5×106, 1×106, 2×106 human umbilical cord mesenchymal stem cel s, once a week, for 3 consecutive weeks. At the end of treatment, blood samples were col ected to measure antinuclear antibody, anti-histone antibody, anti-double stranded DNA antibody changes;OPG and Foxp3 gene expression changes were detected by quantitative PCR method. RESULTS AND CONCLUSION:After treatment, the levels of anti-nuclear antibodies, anti-histone antibodies and anti-double stranded DNA antibodies in the peripheral blood of mice were al declined in the low-, medium-and high-dose groups, while the number of peripheral blood CD4+CD25+T cel s was significantly elevated. OPG and Foxp3 gene expression was also increased dramatical y in the low-, medium-and high-dose groups, which was similar to that in the normal control group and significantly different from that in the model control group (P<0.01). Experimental findings demonstrate that after transplantation of human umbilical cord mesenchymal stem cel s, al relevant indicators in C57BL/lpr mice recovered to the normal levels, and the high-dose treatment group had the most obvious effect.
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AIM:To explore the effects of confluent endothelial progenitor cells (EPCs) derived from young and aged rats on the phenotype conversion, proliferation and migration of vascular smooth muscle cells ( SMCs) .METH-ODS:Mononuclear cells were obtained from the bone marrow of young (1~2 month old) and aged (19 to 26 month old) Sprague-Dawley rats and cultured with medium DMEM/F12 ( containing 15% fetal bovine serum, endothelial cell growth supplements (ECGs) 100 g/L, 1 ×105 units/L of penicillin and streptomycin, respectively).EPCs were characterized as double positive for DiI-Ac-LDL uptake and lectin binding.Abdominal aorta was obtained from 1 to 2 month old Sprague-Dawley rats.Vascular SMCs were cultured by tissue explant method and identified byα-SM-actin immunofluorescence.In transwell co-culture system, the confluent EPCs located in the upper chamber and SMCs were seeded on the lower cham-ber.The experiments were divided into passage 3 SMCs group (P3), passage 4 SMCs group (P4), passage 4 SMCs co-culture with EPCs derived from young rats group (P4YE) and passage 4 SMCs co-culture with EPCs derived from aged rats group (P4AE).The protein expression ofα-SM-actin and osteopontin was detected by Western blotting.[3H]-TdR incor-poration assay was used to determine the proliferation.SMC migration was analyzed by scratch wound healing assay.RE-SULTS:Compared with P3 group,α-SM-actin expression in P4 group significantly decreased and osteopontin protein ex-pression obviously increased, whereas no significant change was found in P4YE group.Compared with P4 group, confluent EPCs derived from young and aged rats both markedly increased α-SM-actin and decreased osteopontin expression in P4 SMCs.Compared with aged rat-derived EPCs, young rat-derived EPCs were more effectively to induce a delayed SMC phe-notype transition (from contractile phenotype to a synthetic phenotype), and to inhibit SMC proliferation and migration. CONCLUSION:Co-culture of confluent EPC induces a delayed vascular SMC phenotype transition and inhibits SMCs pro-liferation and migration.Young rat derived EPCs are more effective to induce a delayed vascular SMC phenotype transition and has stronger inhibitory effects on SMCs proliferation and migration compared with that derived from aged rats.
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Objective To establish a method for isolation of cynomolgus monkey umbilical cord mesenchymal stem cells.Methods Fresh cynomolgus monkey umbilical cord was directly minced into pasty fine pieces, and the pieces were cultured in tissue flask with DMEM/F12 medium supplemented with 10% fetal bovine serum.The morphological characteristics of the resulting cells were examined, and their expression of mesenchymal cell surface markers were analyzed by flow cytometry.The multidifferentiation potential was examined in vitro, too.Results The fibroblast-like cells were successfully isolated from the fresh umbilical cord by an adherent culture procedure.These adherent cells expressed mesenchymal markers including CD29, CD44, and CD90, and also could be induced to differentiate into adipocytes, osteoblasts and chondrocytes.Conclusion Mesenchymal stem cells can be isolated from fresh cynomolgus monkey umbilical cord by using an adherent culture procedure.
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BACKGROUND:If an extract can prolong the S phase and reduce the percentage of apoptosis after co-culture with cels, it is proved that the extract is able to promote cel proliferation. OBJECTIVE: To prove the effects of chicken egg-white extracts with different components on the proliferation, cel cycle and apoptosis of 293T cels. METHODS: An ultrafiltration unit was used to separate chicken egg-white extracts into different components that were > 10 ku, 3 ku and < 3 ku to co-culture with cels for 3 days. Then, cel proliferation, cel cycle and cel apoptosis were detected. RESULTS AND CONCLUSION:Chicken egg-white extract components of < 10 ku and < 3 ku could promote cel proliferation, increase the percentage of S-phase cels and reduce the percentage of apoptosis. In conclusion, chicken egg-white extract components that are < 10 ku and < 3 ku can promote cel proliferation, as wel as increase the percentage of S-phase cels and reduce apoptosis percentage.
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Objective:To analyze the chicken egg-white extracts were co-cultured with cells whether elevated stem cells protein,whether the cells transformation into stem cell.Methods:Four kinds of cells,making a common culture,a 50% chicken egg-white extract co-cultured for 3 days,cells were collected and frozen at -80 degrees,sending the company to do stem cell protein microarray.Results:C57-BMSC has three proteins occurred statistically significant change , TS-UC-MSC has one proteins occurred a statistically significant change ,293T has one protein occurred a statistically significant change ,and 293T-GFP has one protein occurred a statistically significant change.Conclusion:50% chicken egg-white extract co-cultured cells,the cells occurred the phenomenon of transformation into stem cells.
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BACKGROUND:Tree shrew is a representative between insectivore and primates, has a high degree of evolution, is more inexpensive primates, has high use of medical biology, and has been attached by scholars. OBJECTIVE:To detect whether the commonly used secondary antibodies have immune response with tree shrew serum. METHODS:Western blot assay and enzyme linked immunosorbent assay were utilized to detect whether the tree shrew serum had cross-reacts with anti-rabbit, anti-goat, anti-human, anti-mouse, anti-rat, and anti-monkey secondary antibodies. RESULTS AND CONCLUSION:Western blot assay results indicated that tree shrew serums did not react with anti-rabbit, anti-goat, anti-human, anti-mouse, and anti-rat secondary antibodies and had cross reaction with anti-monkey secondary antibody. Enzyme linked immunosorbent assay results also indicated that tree shrew serums were cross-reactive with anti-monkey secondary antibody, but did not have cross-reactivity with the other secondary antibodies. Above data confirmed that the usual y soled secondary antibody cannot be used to immunoassay with tree shrews IgG. Only anti-monkey secondary antibody has cross-react with tree shrew serum. It is necessary to prepare anti-tree shrew IgG monoclonal and polyclonal antibodies. When no antibody is readily available at present, anti-monkey secondary antibody can be used to substitute detection, and can be widely applied in the study of tree shrew models of disease.
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The culture of umbilical cord-derived mesenchymal stem cells is extremely important for studies on umbilical cord mesenchymal stem cells. Optimization of cellculture technology is crucial for clinical application of mesenchymal stem cells and even celltherapy. Meanwhile, the labeling and tracer technique of umbilical cord-derived mesenchymal stem cells is a hotspot in stem celltransplantation. OBJECTIVE:To review the research and development of the cellmarkers and tracer methods of umbilical cord-derived mesenchymal stem cells. METHODS:A computer-based search of VIP, CNKI, Medline, Highwire and Foreign Journals Integration System databases was performed for articles concerning culture and labeling of umbilical cord-derived mesenchymal stem cells published from January 2001 to October 2013. The keywords were“stem cells, mesenchymal stem cells, umbilical cord-derived mesenchymalstem cells, cellculture, labeling methods”in Chinese and English, respectively. Final y, 35 articles were included in result analysis. RESULTS AND CONCLUSION:Umbilical cord-derived mesenchymal stem cells have not yet been widely used, mainly because of the immature isolation, culture and staining techniques of umbilical cord-derived mesenchymal stem cells. These techniques are worthy of further optimization studies. Although in recent years, cellmarkers and tracer technology of umbilical cord-derived mesenchymal stem cell s have made great progress, there are stil many problems need to be solved.
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BACKGROUND:Umbilical cord as childbirth waste has wide variety of sources and can be easily obtained, without any ethical and legal restrictions. Therefore, human umbilical cord mesenchymal stem cells break al the restrictions originated from other sources of mesenchymal stem cells. OBJECTIVE:To review the application of human umbilical cord mesenchymal stem cells in cartilage diseases, neuroglioma, ischemic brain injury, lung disease, liver disease and models of myocardial infarction. METHODS:The PubMed and Wanfang databases were searched by the first author using the keywords of“human umbilical cord mesenchymal stem cells, disease models, celltherapy”in English and Chinese, respectively. Seventy-three articles were searched and final y, 35 articles were included in result analysis. RESULTS AND CONCLUSION:Human umbilical cord mesenchymal stem cells have multilineage differentiation capacity similar to bone marrow mesenchymal stem cells. Compared with bone marrow mesenchymal stem cells, human umbilical cord mesenchymal stem cells have lower immunogenicity. Human umbilical cord mesenchymal stem cells show certain curative effects on cartilage disease, neuroglioma, ischemic brain injury, lung disease, liver disease and myocardial infarction, indicating that human umbilical cord mesenchymal stem cells can be used for celltransplantation to treat various diseases.
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Objective To establish a method of identification of DKO mouse model of Duchenne muscular dystro-phy, and to assess the dystrophin regeneration after stem cell transplantation.Methods Heterozygous mice were mated and the resulting offspring were used to identify their genotype by SSP-PCR.The plasma creatine kinase level was measured by biochemical analyzer and histological changes in the DKO mice were analyzed using HE staining.Human umbilical cord mesenchymal stem cells were prepared and injected into the DKO mice hindlimb muscle, and dystrophin expression was de-tected by immunofluorescence staining at 2 months after injection.Results Mating of heterozygous mice generated three kinds of genotype offsprings, and 21.2%of the offsprings were identified as DKO genotype (285 bp) .DKO mice showed dystrophic symptoms, their plasma creatine kinase level was as high as 16988.52 ±617.48 IU/L, and significant histologi-cal changes including diverse myocyte sizes, numerous centrally nucleated cells and connective tissue proliferation or in-flammatory cells infiltration.Human dystrophin expression was detected in the DKO mouse hindlimb muscle at two months after injection of human umbilical cord mesenchymal stem cells.Conclusion DKO mouse genotype can be identified by SSP-PCR, and DKO mouse is an ideal animal model for studies of stem cell therapy for Duchenne muscular dystrophy.
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BACKGROUND:Reprogramming somatic cells to generate pluripotent stem cells has a wide application in biomedical research. OBJECTIVE:To analyze the effect of different molecular weight proteins in chicken egg-white extract to elevate expression of pluripotent genes Oct-3/4 and Nanog in 293T cells. METHODS:The extracts of chicken egg-white were separated into more than 3 ku and less than 3 ku ingredients to be used for co-culture with 293T cells. There were four groups, 1×105 293T cells per wel , total 500μL. In the control group, 500μL culture medium was added;in the other three groups, 500μL chicken egg-white extract, more than 3 ku and less than 3 ku ingredients were respectively added. Quantitative PCR was used to determine the relative expression levels of pluripotent genes Nanog and Oct-3/4 in 293T cells. RESULTS AND CONCLUSION:By using co-culture method, more than 3 ku ingredients have a role to increase the expression of pluripotent genes Oct-3/4 and Nanog, but less than 3 ku ingredients cannot elevate the expression of pluripotent genes. This indicates that the ingredient of chicken egg-white extract to elevate the expression of pluripotent genes is more than 3 ku proteins.
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BACKGROUND:There are less studies addressing whether bone marrow mesenchymal stem cells from systemic lupus erythematosus patients are different from healthy people. OBJECTIVE:To compare the multi-differentiation capacity of bone marrow mesenchymal stem cells isolated from systemic lupus erythematosus model mice and normal control mice. METHODS:Bone marrow mesenchymal stem cells of systemic lupus erythematosus model mice and C57BL mice were isolated and cultured fol owed by osteogenic and adipogenic differentiations, respectively. Differentiation abilities of two kinds of mouse bone marrow mesenchymal stem cells were observed. RESULTS AND CONCLUSION:Passaged bone marrow mesenchymal stem cells from C57BL mice were long spindle-shaped and evenly distributed, while bone marrow mesenchymal stem cells from systemic lupus erythematosus model mice showed slow growth and were relatively smal er than those from C57BL mice. After osteogenic induction, the amount of calcium salt and calcium nodules were significantly less in the bone marrow mesenchymal stem cells from systemic lupus erythematosus model mice than from normal control mice. PCR detection showed that expressions of Runx2, alkaline phosphatase and osteocalcin were also significantly decreased in the bone marrow mesenchymal stem cells from systemic lupus erythematosus model mice. After adipogenic induction, the number of lipid droplets in the bone marrow mesenchymal stem cells from systemic lupus erythematosus model mice was significantly less than the control group, and PCR detection also showed significantly decreased expression of adipogenic genes, including PPARγ2 and lipoprotein lipase. These findings suggest that the bone marrow mesenchymal stem cells from systemic lupus erythematosus model mice exhibit lower osteogenic and adipogenic capacities than those from normal C57BL mice, and also have the impaired multi-differentiation ability.
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BACKGROUND:Metabolic syndrome is based on sugar, fat and other metabolic disorders and central obesity, hypertension as features in a series of syndrome. The traditional treatment is not yet possible to fundamental y improve and cure metabolic syndrome. OBJECTIVE:To provide an overview of the research progress of stem celltransplantation in the treatment of metabolic syndrome. METHODS:The first author retrieved PubMed database and CNKI database for articles regarding basic research on progress of stem celltransplantation in the treatment of metabolic syndrome, insulin resistance, diabetes, hyperlipidemia and hypertension published from 2002 to 2012. The key words were“stem cells, metabolic syndrome, insulin resistance, diabetes, hyperlipidemia, hypertension, stem cells transplantation”in English and Chinese, respectively. Outdated and repetitive studies were excluded, and 43 literatures were included for summarization. RESULTS AND CONCLUSION:Stem cells are the origin of the body cells, and have self-replicating, highly value-added and differentiation capacity. Stem celltherapy can promote a variety of damage repair and renew aging or death of cells, so as to improve the structure and function of tissues and organs, and to promote the utilization and excretion of metabolites. Studies have shown that stem cells can treat lipid metabolism, insulin resistance, hypertension, hyperglycemia, atherosclerosis and other hazards of metabolic syndrome disorders through a variety of mechanisms. There are many problems to be solved in the treatment of metabolic syndrome with stem celltransplantation. But the existing research data have been confirmed, and stem celltransplantation in the treatment of the metabolic syndrome is a promising new approach.
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BACKGROUND: The inoculation of hybridoma cell strain onto mouse abdominal cavity may obtain ascites containing mass antibody. Previous method to purify monoclonal antibody in ascites is complex and difficult to operate.OBJECTIVE: To prepare, purify and label anti-human leukocyte antigen (HLA)-I class molecule light chain monoclonal antibody, and to detect the expression of tumor cell surface HLA-I class molecules. METHODS: Hybridoma cells were inoculated onto the mouse abdominal cavity. Ascites containing anti-human light chain beta2-microglobulin antibody were obtained and purified with the modified caprylic acid-ammonium sulfate method. The purified monoclonal antibody was labeled with fluorescein isothiocyanate to detect peripheral blood mononuclear cells, T2 cells expressing blank HLA-A2 molecule and K562 cells surface HLA-I class molecules. The expression of HLA-I class molecules was determined by using flow cytometry and fluorescent microscopy. RESULTS AND CONCLUSION: The purified anti-human light chain beta2-microglobulin-fluorescein isothiocyanate monoclonal antibodies accounted for 96% purity. Flow cytometry results showed that, the HLA-I class molecules were highly expressed in peripheral blood mononuclear cells surface, lowly expressed in T2 cells, and not expressed in K562 cells surface. It is a simple and convenient method to purify ascites with the modified caprylic acid-ammonium sulfate method, and according prepare anti-human light chain beta2-microglobulin-fluorescein isothiocyanate. This method is effective to distinguish the levels of HLA-I class molecules expressed in various cells.
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BACKGROUND: Antiviral drugs can reduce the incidence of early-onset cytomegalovirus(CMV)disease,but are associated with strong toxicity and the development of late-onset CMV disease.In order to prevent CMV disease better,cytotoxic T lymphocytes(CTL)may play a critical role in controlling CMV reactivation.Fluorescent HLA-peptide tetramers are used to monitor the recovery of CMV CTL in recipients of allogeneic transplants.OBJECTIVE: To explore the effect of HLA-peptide tetramers and adoptive immunotherapy in treating CMV disease.METHODS: A computer-based online search of Pubmed and Wanfang databases was performed for articles related to CTL detection,application of antiviral drugs and HLA-peptide tetramers,and adoptive immunotherapy with key words"HLA-peptide tetramers,cytomegalovirus,specific CTL,adoptive immunotherapy"in English and Chinese.Repetitive articles were excluded and 29 articles were included.RESULTS AND CONCLUSION: Adoptive immunotherapy with CMVs cytotoxic T cells as preemptive therapy is a very elegant strategy; however,generation of these cells is costly and time-consuming,and therefore the therapy is not available at every transplantation center.Magnetic selection of CMVs CD8+T cells from peripheral blood of CMV-seropositive donors by using HLA-peptide tetramers may be very hopeful,which simplifies adoptive immunotherapy.
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BACKGROUND: There are differences in physical and biological activity between the antibody from mammals and egg yolk antibody (IgY) from chicken. IgY is acid- and heat-resistant, and can prevent and cure the infectious diseases in animals and human being, which is also benefit to develop routine diagnostic immunoassays. Conventional ELISA assay for IgY takes much more time than dot-immunobinding assay.OBJECTIVE: To detect the IgY stability byusing dot-immunobinding assay.DESIGN: Open trail.SETTING: Department of Transfusion, Kunming General Hospital of Chinese PLA.MATERTALS: The experiment was completed in the Kunming General Hospital of Chengdu Military Area Command of Chinese PLA from January to June 2006. Two White Leghorn hens (30 weeks old) were selected. HLA-A*0201 α chain served as the antigen. The total protein concentration of the purified antigen was 0.04 g/L with the molecular mass of 32 000(self-prepared); nitrocellulose filter (NC, import and divided); nonfat dry milk (Anyi Corp. No. 20051220); DAB (Boshide Corp.);caprylic acid (made by Shanghai Xinghuo Chemical Factory); ammonium sulfate (Shantou Guanghua Chemical product).METHODS: ①HLA-A*0201 α chain with the total protein concentration of 0.04 g/L was purified with egg yolk antibody,and identified by SDS-PAGE. ②1 μL antigen was spotted into the center of NC membrane and dried in the incubator at 37 ℃. Then the NC membrane was blocked in 1 mL PBST and put in the incubator at 37℃ with shaking in 90 r per minute for 15 minutes. Then the liquid was exchanged with 1 mL PBST and added the primary antibody at a final concentration of 10 mg/L. After 30 minutes shaking in the incubator at 37 ℃, the NC membrane was washed in PBST for three times. The second antibody, mouse anti-chicken IgY conjugated to horseradish peroxidase (HRP) was added and after 30 minutes incubation, the NC membrane was washed three times in PBST. Binding was revealed by incubation with a DAB reagent. A positive reaction was represented by adeep brown spot,Irdlcating that IgY had better activity; if the spot became lighter IgY lost part activity, and when the spot disappeared, the IgY lost a the activty.According to intensity (gray degree)of the dot compared tothe standard, the remained percent of activity of the IgY was calculated. ③IgY was adjusted to three different protein concentrations with PBS: 1, 0.1, 0.01 g/L and stayed at room temperature for four months. 10 μg lgY was taken out from each concentration sample every month to detect the activity by dot-immunobinding assay. ④IgY was put into seven EP tubes with 100 μL per tube and numbered 1-7. Number 1 to 3 was adjusted pH to 5, 3 and 2, respectively with 1 mol/L HCI; Number 4 to 6 was to 9, 11 and 12, respectively with 1 mol/L NaOH. The pH of number 7 was neutral without adding acid or base. The samples were stayed in incubator at 37 ℃ for 3 hours. 10 μg IgY from each tube was taken every hour to detect the stability at different pH by dot-immunobinding assay. ⑤IgY was added to six EP tubes (10 μL per tube) and numbered 1-6. Number 1-6 was put into waterbath at 30, 40, 50, 60, 70 and 80 ℃ for 15 minutes. After cooled in refrigerator at 4 ℃, 10 mg samples from each tube and standard sample (untreated sample) taken to check the thermal stability by dot-immunobinding assay.MAIN OUTCOME MEASURES: ①SDS-PAGE of IgY. ②IgY stability at room temperature. ③IgY stability at different pH. ④ Detection of IgY thermal stability.RESULTS: ①Purified IgY after SDS-PAGE had two major binds, the molecular mass of the heavy chain was 66.000,and the light chain was 25 000. ②1, 0.1, 0.01 g/L IgY still had partial activity after staying at room temperature for four months. ③When pH ranged from 5 to 9, IgY still had partial activity after staying in 37 ℃ for 3 hours. If pH was lower than 5 or higher than 9, it lost the whole activity in above condition. ④Purified IgY was added to six EP tubes, the number 1-4 still had partial activity, but number 5 and 6 showed some white precipitate, which was caused by protein denaturation at higher temperature.CONCLUSION: IgY stability is higher than others. The dot-immunobinding assay described a rapid and simple method for the demonstration and characterization of functional activity of egg yolk antibody. With only small volume antigen and antibody, and specific dot, the dot-immunobinding assay method could process many samples at the same time.
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Objective To develop ECG Holter system with SD card as storage medium. Methods Data that used MSP430F449 SCM to acquire 3-channel ECG signal to record SD card through serial peripheral interface were reviewed and analyzed on computer. Results Portable ECG Holter System based on SD card is realized. The using of SD card can enhance storage performance. Conclusion Low-cost, and high-performance solution program is observed.
