Objective The purity and activity of islets will greatly affect the outcome of xenotransplantation therapy of type 1 diabetes mell itus. To set up an improved method of the isolation and purification of rat islets, which can obtain highpurity,high-yield, and high-viabil ity islets. Methods Ten healthy and adult male SD rats, weighing 250-300 g were used asorgan donors. Collagenase V was perfused into pancreas via pancreatic duct. Pancreas was digested with collagenase in water bath at 38℃ about 15 minutes, islet purification was performed using two techniques: with Ficoll 400 density gradient (group A), and Ficoll-Paque™ PLUS (group B). Dithizone (DTZ) was util ized for identifying islets, counting islets equivalent quantity (IEQ) and islets’ purity. Trypan blue staining was used to detect the viabil ity of islets. Islets of group B was encapsulated with alginate/poly-L-lysine/alginate (APA). Islets function of microencapsulated and nonmicroencapsulated was evaluated by the insul in release test. Results DTZ staining showed that islets shape were round, ell ipse and irregular with a clear edge and a diameter range of 50-300 μm. The IEQ values were 338.04 ± 76.61 and 834.80 ± 54.00 in groups A and B, respectively, showing significant difference (P lt; 0.05). The purities were 88.31% ± 2.67% and 95.63% ± 1.96% in groups A and B, respectively, showing no significant difference (P gt; 0.05). The activities of islets were 67.40% ± 5.15% and 86.05% ± 2.52% in groups A and B, showing significant difference (P lt; 0.05). Islet APA microcapsules had round shape, unified size, and its diameter was between 1.5 and 2.0 mm. Each microcapsule was encapsulated of 1 to 3 islets. The result of insul in release assay was that the concentrations of insul in secretion with islets of microencapsulated and nonmicroencapsulated were (5.53 ± 1.64) ng/ mL and (4.76 ± 0.26) ng/mL in low glucose, and its concentrations of insul in secretion in high glucose were (11.95 ± 2.07) ng/ mL and (14.34 ± 3.18) ng/mL. Stimulated insul in secretion in high glucose was 2 times more than that in low glucose (P lt; 0.05), but there was no significant difference (P gt; 0.05) in the stimulation index between group A (2.16 ± 0.30) and group B (3.01 ± 0.59). Conclusion The method of islets isolation and purification using Ficoll-Paque™ PLUS own the virtues of more convenient, high islet yield, and high islet purity. Both microencapsulated and nonmicroencapsulated islets show high-viabil ity while culture in vitro.
To set up an economic and effective method for islet isolation from rat, and thereby prove a laboratory protocol of animal model for cl inical islet transplantation. Methods Twenty-five adult male SD rats weighing 230-380 g were used as organ donor. In each of 5 repeated experiments, pancreatic islets of 5 animals were isolated by intraductal infusion of compound sodium chloride injection (CSCI), and subsequently, digested with low concentration (0.5 mg/mL)of collagenase V solution. Islet purification was performed by using a discontinuous density gradient centrifugation thatwas prepared with 27.0%, 23.0%, 20.5% and 11.0% of Ficoll 400. Islet yield and purity were determined by dithizon (DTZ)stain, and propidium iodide (PI)/fluorescein diacetate (FDA) double stain was used to check viabil ity of islets. The endocrine secretory function was assessed by insul in secretion in either low (2.8 mmol/L) or high (25.0 mmol/L) glucose incubation after 3 days of culture in RPMI1640 media. Results Average islet digestion time of 5 experiments was (13.8 ± 1.6) min. Before purification, average isolated number was (5 626 ± 422) islets, and the number was significantly reduced to (2 914 ± 485) islets after purification (P lt; 0.01). The average recovery rate was 51.6% ± 6.0%, and the average yield was (583 ± 97) islets/pancreas. The average purity and viabil ity of islets were 90.2% ± 3.4% and 81.6% ± 7.0%, respectively. After 3 days of culture, insul in secretion of the islets was (116.1 ± 17.4) EU/L in high glucose incubation, which was significantly higher than that of low glucose environment [(39.7 ± 7.5) EU/L, P lt; 0.01)]. The average insul in stimulation index was 3.0 ± 0.4. Conclusion The islet isolation with the CSCI solution and digestion with low concentration of collagenase V decrease experimental cost and also have a beneficial effect on islet recovery and their function.
Objective To explore the isolating methods of rat submandibular gland cell for primary culture. Methods Rat submandibular gland cell were isolated by direct isolation and pancreatin digestion respectively, and then were cultured and subcultured on DMEM. The shape and structure of cultured cells were observed with phase contrast microscope. The cell survival rate was detected by using trypan blue elimination test. The vital force of culture cells was estimated with MTT colorimetric method. The cultured cell secretion function was evaluated by assay of amylase activity. Results By direct isolatin, the cell survival rate was 70% and the cell vital force was 0.16±0.014. By pancreatin digestion, the cell survival rate was 85% and the cell vital force was 0.45±0.13; the cells had good shape and attached well. The Ck8.13 and keratin antibodies were epithelium specific and α-SMA antibodies were myoepithelium specific. The cells were stained positively with CK8.13, keratin and α-SMA antibodies. Conclusion The method of pancreatin digestion for the isolation of submandibular gland cell is better than that of idrect isolation.
ObjectiveTo obtain the mesenchymal stem cells (MSCs) from human umbilical cord and mark in vitro, for further transplantation therapy. MethodsThe MSC were isolated from human umbilical cord by tissue explants culture method. After subculture in vitro, the morphology of hUC-MSC was observed; the surface antigens of hUC-MSC were detected by flow cytometry; adipogenic and osteogenic differentiation were determined by specific staining; hUC-MSC labelled with Brd U were identified by immunofluorescence. ResultsMSC could be isolated successfully by tissue explants culture method. When cultured about one week, the cells climbed out from the tissue block edge, proliferated and formed colonies; the hUC-MSCs of passage 5 were detected by flow cytometry, and they highly expressed CD73, CD90 and CD105, didn't express or lowly expressed CD14, CD34, CD45, CD79a and human leukocyte antigen-DR. After two weeks of adipogenic induction, they were positive in oil red O staining, and after three weeks of osteogenic induction, red precipitate could be seen by alizarin red staining, and the red fluorescence of the hUC-MSC labelled with Brd U could be detected by immunofluorescence detection. ConclusionThe cells can be isolated from human umbilical cord by tissue explants culture method, with the characteristics of hUC-MSCs and can be labeled successfully in vitro, so it can be used for the research in the field of cell transplantation.
Objective To review the general approaches in isolation and purification of pancreatic islets and progress in several aspects. Methods The latest l iterature concerning acquisition of pancreatic islets was reviewed and analyzed interms of the choice of pancreatic islet donors, the digestion and isolation of pancreas, the purification of islet and the assay of outcome. Results The profile of the isolation and purification depends on the selection of reagents and methods of operation in every step and l inkup between every step. Conclusion Pancreatic islet transplantation is the most effective method to treat type 1 diabetes, the problem of inadequate sources of pancreatic islets could be resolved by the optimal process and the establ ishment of standardized operation.
ObjectiveTo review the current progresses in purification strategies, biological characters, and functions of endothelial progenitor cells (EPCs) derived extracellular vesicles (EVs) (EPC-EVs). MethodsRecent relevant publications on the EPC-EVs were extensively reviewed, analyzed, and summarized. ResultsEPC-EVs are usually isolated by differential centrifugation and exhibit a homogenous pattern of spheroid particles with a diameter ranging from 60 to 160 nm under transmission electron microscopy. EPC-EVs are positive for cell-surface markers of EPCs (CD31, CD34, and CD133), and negative for markers of platelets (P-selectin and CD42b) and monocytes (CD14). Recent studies have shown the effectiveness of EPC-EVs in ischemic injuries, anti-Thy1 glomerulonephritis, and cardiomyocyte hypertrophy, and also shown their predictive role in cardio-cerebral-vascular diseases. ConclusionAn alluring prospect exists on the EPC-EVs-related research. Further studies are required to decipher the composition of EPC-EVs and their precise role in pathophysiological processes, and to investigate the molecular mechanisms for their targeting and function.
Objective To find effective ways for controlling the hospital infection to the skeptical gas gangrene patients. Method From May 14th to June 24th, the hospital set up triage spots originally and dealt with the wounded based on their specific conditions in different stages and optimized the flow of admission of the wounded. Owing to correctly treating the wound and screening the skeptical gas gangrene patients, preventing nosocomial infections was shifted forward. Sprending the gas gangrene wound after having flushed it with 3% H2O2. If the wound have been stitched, the stitches should bee taken out, and open the wound and take the debridement for it completely, then treat it with b antibacterial after debridement by sterilization and isolation about operation of gas gangrene. Result Up to June 24th, none of 67 cases of doubtful gas gangrene from the disaster area died and no hospital cross infections happened in courtyard. At present, amomg the 67 cases, 32 were highly suspected of gas gangrene infection, 26 cases were discharged, while 6 cases were undergoing treatment in the hospital. Conclusion Correct management and appropriate treatment are effective ways for controlling hospital cross infection to the skeptical gas gangrene patients.
In order to solve the problems of difficult test, high cost and long cycle in the development of large-scale airborne negative pressure isolation system, the simulation analysis of negative pressure response characteristics is carried out around various aviation conditions such as aircraft ascending, leveling and descending, especially rapid decompression, based on the computational fluid dynamics (CFD) method. The results showed that the isolation cabin could achieve –50 Pa pressure difference environment and form a certain pressure gradient. The exhaust air volume reached the maximum value in the early stage of the aircraft’s ascent, and gradually decreased with the increase of altitude until it was level flying. In the process of aircraft descent, the exhaust fan could theoretically maintain a pressure difference far below –50 Pa without working; Under the special condition of rapid pressure loss, it was difficult to deal with the rapid change of low pressure only by the exhaust fan, so it was necessary to design safety valve and other anti-leakage measures in the isolation cabin structure. Therefore, the initial stage of aircraft ascent is the key stage for the adjustment and control of the negative pressure isolation system. By controlling the exhaust air volume and adjusting parameters, it can adapt to the change of low pressure under normal flight conditions, form a relatively stable negative pressure environment, and meet the needs of biological control, isolation and transport.
ObjectiveTo investigate the hand hygiene status of nursing staff in coronavirus disease 2019 (COVID-19) isolation ward, find out the difficulties and problems in hand hygiene implementation, and then put forward scientific and feasible suggestions to improve the compliance of hand hygiene.MethodsSelf-designed Questionnaire on Hand Hygiene Status of Nursing Staff in COVID-19 Isolation Ward was distributed through the Wenjuanxing, a platform to collect data. The questionnaire, which included general information, knowledge related to hand hygiene, and the status of hand hygiene in isolation ward, was distributed to the nurses working in isolation wards in Wuhan, Hubei Province from March 15th, 2020 to March 22nd, 2020.ResultsValid questionnaires were collected from 492 nurses. The difficulty in performing hand hygiene in the isolation ward was ranked ≥level 3 by 248 nurses (50.41%), the degree of which was divided into 10 levels (level 1 was no difficulty, level 10 was the most difficult). A total of 369 participants (75.00%) thought that wearing gloves for hand disinfection would damage the gloves. There were 161 participants who thought that gloves should be changed every 2 hours, accounting for the largest proportion (32.72%); while 226 participants actually changed gloves every 4 hours, accounting for the largest proportion (45.93%).ConclusionsThe difficulty of performing hand hygiene in isolation ward should be paid attention to. It is recommended to carry out further research on the replacement time of gloves.
Objective To review the common methods of isolation and purification of porcine islets and research progress. Methods Domestic and abroad literature concerning the isolation and purification of porcine islets was reviewed and analyzed thoroughly. Results The efficacy of the isolation and purification depends on the selection of donor, the procurement and cryopreservation of high-quality donor pancreas, and the selection and improvement of the operation. Conclusion The shortage of transplanted islets could be resolved by the establishment of standardized and optimal process, which may also promote the development of porcine islet xenograft.