Objective To investigate the effect of alpha 1-antitrypsin (A1AT) concerning in reducing the injury of transplanted islets by pancreas exocrine cells and promoting proliferation of the pancreas B cells.Method The pancreases of mice were digested with collagenase,islets were isolated artificially,and pancreatic exocrine cells were collected.In purified islet group (n =6),100 islets were seeded into a 6 well culture plate.In experimental group(n =6),100 islets were co-cultured with equal volume of pancreas exocrine cells,and 0.5 mg/mL A1AT was added into a 6-well culture plate.In control group(n =6),100 islets were co-cultured with equal volume of pancreas exocrine cells.After 48 h,insulin content of islets in each well and trypsin concentration in the supernatant of each well were measured.The islets were cultured in low sugar and high sugar 1640 medium,then glucose stimulated insulin secretion (GSIS) test was carried out.In vivo,8-9-week old male BALB/C mice were induced with STZ (190 mg/kg body weight,i.p) to establish the diabetic model and randomly divided into two groups.In experimental(n =10) and control(n =10) groups,250 islets and the equal volume of pancreatic exocrine cells were transplanted into different regions of left kidney subcapsule,resepctively.The experimental group was injected with A1AT (83 mg/kg,qd,i.p) for 28 days after operation,and the control group was injected with the same amount of normal saline (qd,i.p) for 28 days.Both two groups were given EDU (5 μg/g,qd,i.p) for 28 days.The blood glucose level was monitored continually.Nephrectomies were performed after 28 days.The expression of anti-amylase antibodies in the renal subcapsule was detected by immunohistochemical staining,and the proliferation of islet beta cells was examined using immunofluorescence staining.Result Insulin levels and insulin stimulation index in the control group were decreased as compared with those in the purified islet group; those in the experimental group were higher than in the control group,but lower than in the purified islet group.Trypsin concentration in the control group was increased as compared with the purified islet group,that in the experimental group was lower than the control group,but higher than in the purified islet group (all P＜0.01).After islets transplantation,the blood glucose levels in control and experimental groups were normal,but those in the control group recovered later than in the experimental group (P＜0.01).At 3rd day after nephrectomy,the blood glucose levels were ＞21 mmol/L in both two groups.A large number of anti-amylase antibody-positive cells were found in the renal subcapsule in the control group while little seen in the experimental group after 28 days.The immunofluorescence showed that the insulin +/EDU + B cells in the experimental group were more than those in the control group.Conclusion Conclusion Co-culture of islets and pancreatic exocrine cells with A1AT can prevent islet cells from damage caused by trypsin.A1AT could inhibit the secretion of pancreatic amylase from pancreatic acinar cells and promote proliferation of islet beta cells.

Objectives To explore the effect of fatigue intervention on biomechanics of lower extremity and performance during the stretch-shortening cycle(SSC) movement-drop jumps(DJ).Methods The Vicon motion capture system and 3D Kistler force plates were used to collect sagittal plane kinematics and ground reaction force data synchronously of a total of fifteen trained male athletes under pre-and post-fatigue conditions with shuttle running + vertical jumping fatigue protocol.The joint angle,joint moment,power,work,and leg/joint stiffness were compared before and after fatigue.Results After fatigue,the maximum height of DJ decreased(P＜0.05),while the touchdown angle and the range of motion(△θ) of knee and ankle joints,as well as the occurrence time for the eccentric,concentric and total phase increased(P＜0.05).However,the maximum push-off moment and power of knee reduced(P＜ 0.05).The stiffness of knee and ankle joints during the eccentric phase reduced,resulting in the reduction of the leg stiffness(P＜0.05).Moreover,the energy absorption and net energy of the ankle joint decreased;meanwhile,the energy contribution of the knee joint decreased during the eccentric phase of a DJ task.Conclusion Fatigue changes the movement pattern,decreasing the control ability of the lower extremity especially in the knee and ankle joint,and results in decreased performance.Moreover,the decrease of leg,ankle and knee stiffness and the corresponding energy can be used as sensitive indexes to evaluate the performance of drop jumps in a fatigued condition.

The research progress in fatigue protocols and biomechanics of lower extremity and its relationship with injury induced by exercise-induced fatigue was reviewed in this paper. At present, fatigue protocols can be divided into the traditional fatigue-induced protocol and the functional fatigue-induced protocol under laboratory condition. The former mainly includes power-cycling model, treadmill run model and step-ups model, while the latter is closer to what is experienced during competition, which is usually shown as multidirectional movements. In addition, the biomechanical measures of exercise-induced fatigue mainly include kinematics, ground reaction force, joint mechanics and electromyography. Different fatigue protocols do not uniformly produce alterations in lower limb biomechanical factors. The refinement of fatigue protocols and specific indicators should be considered in future studies, in order to compare the induced effects of fatigue protocols and provide references for the selection of fatigue protocols in laboratory tests. Meanwhile, the relationship between the response of brain-nerve system and the activation of musculoskeletal system for specific athletic task should be focused, so as to understand the difference of biomechanical mechanisms between fatigue protocols and further explore the effect of exercise-induced fatigue on sports injuries.

Ethyl carbamate as a potential carcinogen commonly exists in traditional fermented foods and beverages. Enzymatic removal of ethyl carbamate from fermented foods and beverages is an efficient and safe method. In this study, we mutated urethanase from Lysinibacillus fusiformis SC02 on the Q328 site through computer aided design approaches. The half-life of resulting mutants Q328C and Q328V was detected to be 7.46 and 1.96 folds higher than that of the original enzyme, and Q328R presented better thermal-tolerance than the original urethanase when incubated at high temperature. The tolerance of Q328C to ethanol and acid also increased when compared with that of the original enzyme. The stability and tolerance to acid and ethanol of urethanase could be improved by modification on its Q328 site.
Amidohydrolases ; biosynthesis ; genetics ; Bacillaceae ; enzymology ; genetics ; Bacterial Proteins ; biosynthesis ; genetics ; Computer-Aided Design ; Enzyme Stability ; Ethanol ; Mutagenesis, Site-Directed ; Protein Engineering