Objective To introduce the occurrence mechanisms, prevention, and treatment measures of prosthetic aseptic loosening. Methods The recent original articles about prosthetic aseptic loosening were extensively reviewed and analyzed. Results Prosthetic aseptic loosening was a very complex process involving many mechanical and biological aspects. The main mechanical factors included prosthetic materials, shapes and sizes, implant fixation methods (including surfacetreatments), cl inical installation, interface micromotion, stress shielding, implant wear, interface integrity, and peri prosthetic high hydraulic pressure, etc.; the main biological factors included the types and sizes of wear particles, cell-activated responses, cytokine release, enzyme activation and allergic reactions to wear particles, etc.. Many measures should be adopted to effectively prevent and treat it, including improving materials and designs of prostheses, fixation techniques, surgical techniques, and drug treatments. Conclusion Prosthetic aseptic loosening is still a troublesome compl ication after joint replacements in orthopaedics, and more attention should be paid for its effective prevention and treatment.
【Abstract】 Objective To investigate both incidence and mechanism attributing to steroid-associated osteonecrosisof femoral head(ONFH) using an experimental protocol with a single low-dose l i popolysaccharide (LPS) injection andsubsequently three injections of high-dose methylprednisolone (MPS). Methods Twenty-five New Zealand white rabbits with body weight of (3.0 ± 0.3) kg were divided randomly into 2 groups. In treatment group, 19 rabbits received one intravenous injection of LPS (10 μg/kg); 24 hours later, three injections of 20 mg/kg of MPS were given intramuscularly at an interval of 24 hours. Additional 6 rabbits which received normal sal ine injection at the same time point were used as controls(control group). The blood samples were collected for hematological examinations before and after LPS injection, MRI was performed on bilateral hip six weeks after last MPS injection, meanwhile, bone marrow was aspirated from femoral head region to evaluate stem cell’s activity. Bilateral femoral heads were harvested to make histopathology examination. Results All animals survived throughout the experiment period except one death on the second day after LPS injection. In the histopathological examinationfor the femoral head, ONFH+ was observed in 16 rabbits (88.9%), and the lesions were mainly in the metaphysis. In ONFH+ rabbits, micro vessels fibrous thrombosis and extravascular marrow fat cell size increasing were found around necrotic bone; The femoral heads of control group had no changes. MRI accurate ratio was 93.8% (15/16). Compared to basel ine, a significant decrease in ratio of tissue plasminogen activator/plasminogen activator inhibitor 1 and activated partial thromboplatin time, and a significant increase in ratio of low-density l ipoprotein/high-density l ipoprotein were only found in ONFH+ rabbits (P lt; 0.05). Meanwhile there was a significant decrease in the number of CFU-F (8.50 ± 9.63) compared with the control (70.17 ± 7.78, P lt; 0.05). Conclusion A single low-dose LPS injection and subsequent three injections of high-dose MPS is effective on building steroid-associated ONFH model, coagulation and l ipometabol ism abnormal ity, activity degeneration of stem cell may be the key factors of ONFH.
Postoperative cognitive dysfunction (POCD) is a common and important complication after cardiac surgery. The pathological reactions caused by cardiac surgery, such as traumatic stress reaction, inflammation, hemodynamics disorders, and blood coagulation dysfunction, by triggering central inflammation, ischemia, hypoxia and ischemia-reperfusion injury and other mechanisms, leading to brain function-impairment, causing the development of POCD. According to the above mechanisms, taking corresponding protective measures, reducing the development of POCD, and improving the quality of life after cardiac surgery are of great importance.
Objective To summarize current research advances of mechanism and treatment of pancreatic endocrine and exocrine insufficiency in chronic pancreatitis. Method The related literatures about the research progress of the pancreatic endocrine and exocrine insufficiency in the chronic pancreatitis in recent years were retrieved and reviewed. Results In recent years, it had many new studies and discoveries on the pancreatic endocrine and exocrine insufficiency in the chronic pancreatitis. The mechanism of the pancreatic exocrine dysfunction was mainly due to the decrease of the pancreatin secretion in the patients with chronic pancreatitis. The mechanism of the pancreatic endocrine insufficiency was mainly due to the damage of the pancreatic exocrine gland and islet tissue in the chronic pancreas, which leaded to the destruction of the pancreatic endocrine cells, the other endocrine cells, and the disturbance of the intestine-islet axis, followed by the disorder of the various hormones (insulin, glucagon, pancreatic polypeptide, etc.), and eventually manifested the glucose tolerance or dominant diabetes. Conclusions At present, although there is a certain degree understanding for pancreatic endocrine and exocrine insufficiency in chronic pancreatitis, there are no breakthroughs in its mechanism and treatment, and effect is lack of large sample and multicenter clinical control study. Exploring more optimized detection methods and establishing a perfect treatment system is goal of future development and research.