[ ABSTRACT] AIM:To observe the treatment effect and its immune regulation of human amnion epithelial cells ( hAECs) on Alzheimer’ s disease ( AD)-like pathology rat model.METHODS: The hAECs were isolated from amnion with trypsin digestion, and the phenotype of hAECs was analyzed by flow cytometry.SD rats ( n=48) were randomly divid-ed into sham control group, model group, medium group and hAECs group.AD-like pathology rat model was induced by bilateral intraventricular injection of lipopolysaccharide (LPS).hAECs (5 ×105) were injected into the hippocampus of the AD-like pathology rats.At 2 weeks after transplantation, the animals were tested by Morris water maze to observe the function of learning and memory.The pathological change of the brain was observed by HE staining.The expression of am-yloid β-protein 42 (Aβ42) and Tau protein and the level of acetylcholine (ACh) in the injury brain were determined by immunohistochemistry.The survival and differentiation of hAECs in the hippocampus were measured by immunofluorescent technique.The percentages of lymphocyte subsets in the peripheral blood mononuclear cells were analyzed by flow cytome-try.The contents of serum cytokines were detected by cytometric bead array.RESULTS:Compared with model group and medium group, hAECs group showed shortened escape latency ( P<0.01) , increased frequency of going through the plat-form (P<0.05), reduced loss of hippocampal neurons, decreased expression of Tau protein and Aβ42 in the hippocampus (P<0.05), increased ACh level in the hippocampus (P<0.05), decreased percentages of Th1 and Th17 subsets, in-creased percentages of Th2 and Treg cells ( P<0.05) , decreased concentrations of IFN-γand IL-2 in the serum, and in-creased concentration of IL-4 ( P<0.05 ) .CONCLUSION: hAECs improve the cognitive learning and memory function and alleviate pathologic damage of hippocampus through immune regulation in AD-like pathology rats.

Objective To investigate the clinical,imaging,pathological and molecular biological features of mitochondrial encephalomyopathy with lactic acidosis and stroke -like episodes(MELAS)in children.Methods The clinical,imaging,pathological and molecular biological features of 1 2 children with MELAS diagnosed through muscle biopsy or gene sequencing in the Fifth Affiliated Hospital of Zhengzhou University from January 201 1 to December 201 5 were retrospectively analyzed.Results (1 )Clinical features:the main manifestations included headache and vomiting in 1 1 cases,epileptic seizures in 9 cases,short stature in 8 cases,hairy in 7 cases,intolerance fatigue in 7 cases,cogni-tive decline in 7 cases,visual disturbance in 6 cases,hearing disturbance in 6 cases,and 5 cases had positive family history.In addition,7 cases had the serum lactic acid level increase in a rest for 1 0 min after exercise.(2)Imaging fea-tures:4 cases showed bilateral basal ganglia calcification symmetry in 8 patients who underwent head CT scan.The most frequently involved parts of the lesion were occipital in 1 0 cases,temporal in 9 cases and parietal lobe in 7 cases in stroke -like episodes.The lesions were lamellar necrosis.The abnormal areas by MRI showed low signal intensity on T1 weighted imaging,high signal intensity on T2 weighted imaging and fluid attenuated inversion recovery,high or equal signal intensity on diffusion weighted imaging,high or low signal intensity on apparent diffusion coefficient;the lactate peak significantly increased on magnetic resonance spectroscopy.The distribution was not in accordance with the control region of the cerebral vessels.Dynamic observation revealed that the lesions were reversible and migratory.(3)Myo-pathological features:muscle biopsy was performed in all children,and ragged -red fibers were found in 1 0 cases by im-proved Gomori staining,strongly succinate dehydrogenase -reactive were found in 9 cases,and the lipid droplets slight-ly increased in 8 cases by oil red O staining.Besides,the crystalline inclusion bodies in mitochondria were arranged in a parking lotpattern in 9 cases by electromicroscope.(4)Molecular biological characteristics:the mitochondrial gene mutations were analyzed in peripheral blood of 9 children and their parents,including 8 cases with A3243G muta-tion and 1 case with G13513A mutation.Five mothers had the same A3243G mutation site in 8 cases.Conclusions Children with MELAS have complex and varied clinical manifestations and certain characteristic of neuroimaging.More-over,muscle pathology and gene sequencing have important diagnostic value.Fully understanding the clinical,muscle pathology,imaging and molecular biological characteristics of children with MELAS can be helpful to the early diagnosis and treatment,also reduce misdiagnosis.

Objective:To establish a three-dimensional model of locking plate fixation for 42A2 type oblique tibial fractures with different fracture line directions and different angles between the fracture line and the long axis of the tibia. Finite element analysis was used to calculate and analyze the biomechanics of locking plate, screw, and tibia, providing theoretical basis for clinical application.Methods:A healthy adult volunteer, 25 years old, male, with a height of 173 cm and a weight of 69.5 kg, was selected to perform computed tomography (CT) scans on the left tibia. Relevant data were obtained to establish a locking steel plate fixation model for 42A2 type tibia with different oblique fracture line directions and different angles between the fracture line and the long axis of the tibia. Eight hole pure titanium plates were used for fixation, respectively. We compared the Mises stress changes of locking plates, screws, and tibia in different angle fracture models.Results:In the case of a 42A2 type fracture in the left oblique direction with a fracture line from outside to inside, the maximum Mises stress in the tibia was 114 MPa, the maximum Mises stress in the screw was 279.8 MPa, and the maximum Mises stress in the locking steel plate was 302.4 MPa; In the case of a 42A2 type fracture in the right oblique fracture with a fracture line from the bottom to the top, the maximum Mises stress of the tibia was 93.41MPa, the maximum Mises stress of the screw was 353.4 MPa, and the maximum Mises stress of the locking steel plate was 411.8 MPa.Conclusions:Regardless of the oblique fractures in both left and right directions, the maximum stress values are: locking plate>screw>tibia; When the position of the locking steel plate is fixed, the maximum stress values of the locking steel plate and screw are both right oblique fracture>left oblique fracture; And the maximum stress values all increase with the increase of angle.

Objective　To investigate the muscle pathology and electron microscopy characteristics of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episode.Methods　Muscle pathology and electron microscopy data from 33 cases of MELAS syndrome confirmed by muscle pathology and gene sequencing in the Fifth Affiliated Hospital of Zhengzhou University and the First Affiliated Hospital of Zhengzhou University from January 2013 to January 2019 were collected and analyzed retrospectively.Results　RRF were found in 25 cases under the light microscope by modified Gomori staining.Ragged-blue fibers (RBF) were found in 28 cases by SDH staining,and the activity of oxidase was increased.In 26 cases,the arterial walls of intermuscular arterioles were strongly SDH-reactive,suggesting SSV phenomenon,in which 2 cases RBF and RRF were not seen.The activity of oxidase was disappeared or decreased in 22 cases by COX staining,indicating COX negative muscle fiber.Fifty patients were examined by electron microscopy,the number and structural abnormalities of mitochondria were observed.Besides,the crystalline inclusion bodies in mitochondria were arranged in a “parking lot” pattern.Conclusion　RRF,SSV phenomenon and negative muscle fiber by COX staining were the main pathological changes of muscle in MELAS syndrome.The inclusion of the crystalline inclusions in the mitochondria was a “parking lot” arrangement,which was a typical change in the electron microscope of MELAS syndrome.These characteristics were very important for the diagnosis of MELAS syndrome.