Objective To compare the effects of flap delay and vascular endothelial growth factor (VEGF) on the viability of the rat dorsal flap. Methods Thirty rats were divided into 3 groups: saline group, flap delay group and VEGF group. The rats in flap delay group underwent flap delay by keeping bipedicle untouched, and the cranial pedicle was cut 7 days later. The rats in VEGF group were given VEGF solution locally when the flaps were elevated in the operation. The ratsin saline group were given saline solution in the same way. Five days after thesingle pedicle flaps were performed, the flap survival rate was measured. Theflap tissues were collected to measure and analyze the microvascular density, diameter and sectional area by immunochemical method. Results The flap survival rate of flap delay group was similar to that of VEGF group andthere is no statistically significant difference(Pgt;0.05). The vascular diameter of flap delay group was much larger than that of saline group and VEGF group, showing statistically significant difference (Plt;0.05). The vascular density of VEGF group was much higher than that of saline group and flap delay group, showing statistically significant difference (Plt;0.05). The vascular sectional area of flap delay group was similar to that of VEGF group(Pgt;0.05). Conclusion The change in the flap after flap delayis manifested as obvious dilatation of microvessels, while the change in the flap after the injection of VEGF is manifested as obvious vascular proliferation. Both flap delay and VEGF can increase the vascular sectional area and the viability of the flap, but the mechanism is different.
New biodegradable intravascular stent can reduce risk of foreign bodies retained, thus, it is widely concerned and some of the products have been introduced into the clinic. However, the characteristic of biodegradable may lead to more safety concerns associated with thrombosis. To ensure the safety, the thrombus formation experiment in vivo needs to be carefully designed and evaluated based on GB/T 16886.4 standard, but current standard do not provide explicit testing and evaluating methods. Establishing animal model with experimental pigs, the study compares biodegradable coronary stents and metal stents by simulating clinical implantation in vivo on the thrombus formation in the implanting process, and after the short-term and long-term implantation. The evaluation methods include gross observation, digital subtraction angiography intraoperative analysis, optical coherence tomography analysis, scanning electron microscopy and so on. The results show that combining these methods could comprehensively evaluate the whole process of the thrombus formation from the beginning of implantation to the end of preclinical animal experiments, so that, it may better predict the clinical thrombosis risk, and the selection of the control was very important. The study tries to use the comparison examples of thrombosis on the new medical instrument to provide the clue for thrombosis evaluation in vivo on similar instruments and show the methodology on the preclinical evaluation.
Objective To make a comparative study on the effects of whole bone marrow culture method and density gradient centrifugation method in isolating hBMSCs. Methods hBMSCs were obtained from healthy adult volunteers and isolated by whole bone marrow culture method and density gradient centrifugation method. Primary cell morphology was observed using inverted phase contrast microscope and the cells in the 2nd passage were stained with HE after being cultured for 7 days. And then, the generation time of the primary, 2nd and 3rd passage hBMSCs was comparedbetween two methods and the surface markers were detected by flow cytometer. In addition, the ALP expression inosteoinductive hBMSCs were evaluated by ALP activity kit at 3, 6 and 9 days and ALP staining was used for osteoinductivehBMSCs with Kaplow method at 9 days. Results Primary cells isolated with whole bone marrow culture method showedaggregation growth while cells isolated with density gradient centrifugation method showed diffusion growth. HE stainingshowed no significant difference in the morphology of the 2nd passage cells between these two methods. The generationtime of primary cells isolated by whole bone marrow culture method (15.36 ± 1.67) days was significantly shorter than that of cells isolated by density gradient centrifugation method [(18.57 ± 1.05) days] (P lt; 0.01), while the generation time of the 2nd and 3rd passage cells showed no statistically significant differences between these methods (P gt; 0.05). The concent of positive surface markers (CD29, CD44, CD71, CD105, CD166) and negative surface marker CD34 in the 2nd cells showed no significant difference between these two isolation methods (P gt; 0.05); however, negative markers CD14 and CD45 showed significant difference (P lt; 0.01). The ALP expression in osteoinductive cells showed no statistical significant (P gt; 0.05) at 3, 6 and 9 days; and the ALP staining positive cell ratio of whole bone marrow culture method was basically in accordance with that of density gradient centrifugation method at 9 days. Conclusion hBMSCs could be isolated by whole bone marrow culture method, and the cell isolation effects of whole bone marrow culture method are equivalent with density gradient centrifugation method.
ObjectiveTo report a new type of anatomical locking plate for sternocalvicular joint, and investigate its effectiveness in treatment of sternoclavicular joint fracture and dislocation.MethodsA new type of anatomical locking plate for sternoclavicular joint was developed, which accorded with the anatomical features and biomechanical characteristics of Chinese sternoclavicular joint. By adopting the method of clinical randomized controlled study, 32 patients with the sternoclavicular joint fracture and dislocation who met the selection criteria between June 2008 and May 2015 were randomly divided into groups A and B (n=16), and the patients were treated with new anatomic locking plate and distal radial T locking plate internal fixation, respectively. There was no significant difference between 2 groups in gender, age, injured side, body mass index, cause of injury, type of injury, the time from injury to operation, and preoperative Rockwood grading score (P>0.05). The operation time, intraoperative blood loss, incision length, hospitalization time, and postoperative complications in 2 groups were recorded, and the effectiveness was evaluated by Rockwood grading score.ResultsThe operations of 2 groups completed successfully. The operation time, intraoperative blood loss, and hospitalization time in group A were significantly less than those in group B (P<0.05), but there was no significant difference in the incision length between 2 groups (t=0.672, P=0.507). All the patients were followed up 18-30 months (mean, 24 months). In group A, there were 1 case of sternoclavicular joint pain and 2 cases of wound infection; in group B, there were 1 case of sternoclavicular joint pain, 1 case of internal fixation loosening, and 1 case of sternoclavicular joint re-dislocation; there was no significant difference in complication incidence between 2 groups (P=1.000). The Rockwood grading scores at each time point after operation in 2 groups were significantly higher than those before operation. At 1 month after operation, the Rockwood grading score in group A was significantly higher than that in group B (t=2.270, P=0.031); but there was no significant difference in the Rockwood grading scores between the 2 groups at 6 months and at last follow-up (P>0.05). At last follow-up, according to the Rockwood scoring standard, the results of group A were excellent in 13 cases, good in 2 cases, poor in 1 case, the excellent and good rate was 93.75%; the results of group B were excellent in 11 cases, good in 4 cases, poor in 1 case, and the excellent and good rate was 93.75%; there was no significant difference between 2 groups (Z=–0.748, P=0.455).ConclusionThe new type of anatomic locking plate accords with the Chinese anatomical characteristics. It has the advantages of easy operative procedure, less surgical trauma, shorter operation time, less intraoperative blood loss, shorter hospitalization time, and it can achieve better results in the treatment of sternoclavicular joint fracture and dislocation.
Objective To explore the independent risk factors for hospital infections in tertiary hospitals in Gansu Province, and establish and validate a prediction model. Methods A total of 690 patients hospitalized with hospital infections in Gansu Provincial Hospital between January and December 2021 were selected as the infection group; matched with admission department and age at a 1∶1 ratio, 690 patients who were hospitalized during the same period without hospital infections were selected as the control group. The information including underlying diseases, endoscopic operations, blood transfusion and immunosuppressant use of the two groups were compared, the factors influencing hospital infections in hospitalized patients were analyzed through multiple logistic regression, and the logistic prediction model was established. Eighty percent of the data from Gansu Provincial Hospital were used as the training set of the model, and the remaining 20% were used as the test set for internal validation. Case data from other three hospitals in Gansu Province were used for external validation. Sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUC) were used to evaluate the model effectiveness. Results Multiple logistic regression analysis showed that endoscopic therapeutic manipulation [odds ratio (OR)=3.360, 95% confidence interval (CI) (2.496, 4.523)], indwelling catheter [OR=3.100, 95%CI (2.352, 4.085)], organ transplantation/artifact implantation [OR=3.133, 95%CI (1.780, 5.516)], blood or blood product transfusions [OR=3.412, 95%CI (2.626, 4.434)], glucocorticoids [OR=2.253, 95%CI (1.608, 3.157)], the number of underlying diseases [OR=1.197, 95%CI (1.068, 1.342)], and the number of surgical procedures performed during hospitalization [OR=1.221, 95%CI (1.096, 1.361)] were risk factors for hospital infections. The regression equation of the prediction model was: logit(P)=–2.208+1.212×endoscopic therapeutic operations+1.131×indwelling urinary catheters+1.142×organ transplantation/artifact implantation+1.227×transfusion of blood or blood products+0.812×glucocorticosteroids+0.180×number of underlying diseases+0.200×number of surgical procedures performed during the hospitalization. The internal validation set model had a sensitivity of 72.857%, a specificity of 77.206%, an accuracy of 76.692%, and an AUC value of 0.817. The external validation model had a sensitivity of 63.705%, a specificity of 70.934%, an accuracy of 68.669%, and an AUC value of 0.726. Conclusions Endoscopic treatment operation, indwelling catheter, organ transplantation/artifact implantation, blood or blood product transfusion, glucocorticoid, number of underlying diseases, and number of surgical cases during hospitalization are influencing factors of hospital infections. The model can effectively predict the occurrence of hospital infections and guide the clinic to take preventive measures to reduce the occurrence of hospital infections.
Regulatory science of medical devices serves the scientific research and regulatory activities for supervision of medical devices. Principles of science and transparency and conduction of evidence-based study, which is advocated in Evidence-based science(EBS), also apply to regulatory science of medical devices, including using evidence-based scientific tools and methods to demonstrate the safety and effectiveness, as well as quality, efficacy and cost-effectiveness of total life cycle of medical products, target customers, and scope. EBS provides both new methods and tools for regulatory science for medical devices, and provides a new basis for further scientific regulatory decisions.