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Objective@#To investigate the molecular mechanism of down-regulation of monocarboxylic acid transporter 1 (MCT1) on the proliferation inhibition of glioma cell.@*Methods@#siMCT1, siMCT4 and negative control siRNA were transfected into glioma cell lines including U-251 and U-87. The proliferation activities of U-251 and U-87 cells were detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) assay and clonogenic assay. Glucose consumption and lactic acid efflux of U-251 and U-87 cells were determined by spectrophotometry.Western blot was used to detect the expressions of MCT1, MCT4, human glucose transporter 1 (GLUT1), GLUT4, tuberous sclerosis associated protein (TSC2), p-TSC2, 4E binding protein 1 (4EBP1), p-4EBP1, ribosomal S6 protein kinase (S6) and p-S6 protein in U-251 and U-87 cells.@*Results@#Compared with negative control group, siMCT1 and siMCT4 significantly inhibited the expressions of MCT1 and MCT4 protein in U-251 and U-87 cells (both P<0.05). However, only knockdown of MCT1, the proliferation activities of U-251 and U-87 cells significantly decreased (P<0.05). The clone formation rates of U-251 and U-87 cells decreased to (55.20±3.27)% and (68.33±4.58) %, respectively (P<0.05). The glucose consumption of U-251 and U-87 cells in the negative control group at 72 hours were (82.65±6.66) pmol/L and (63.33±5.27) pmol/L, respectively, significantly higher than (31.70±3.17) pmol/L and (26.41±3.19) pmol/L of the siMCT1 transfected group (P<0.05). The extracellular lactate flow of U-251 and U-87 cells in negative control group at 72 h were (155.49±8.15) mmol/L and (135.37±8.21) mmol/L, respectively, significantly higher than (42.69±4.66) mmol/L and (38.91±4.83) mmol/L of the siMCT1 transfected group (P<0.05). Western blot analysis showed that knockdown of MCT1 significantly decreased the protein levels of GLUT1 p-TSC2, p-4EBP1 and p-S6 in U-251 and U-87 cells.@*Conclusions@#Downregulation of MCT1 expression can inhibit the proliferation of glioma cells. Deletion of MCT1 inhibits the glycolysis and metabolism of glioma cells through regulating the mTOR signaling pathway.
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Objective To discuss clinical significance on early diagnosis of brain injury in premature infants with multiple sequence joint inspection of magnetic resonance imaging (MRI).Methods The brain MRI findings of 160 premature infants treated by Neonatal Intensive Care Unit were analyzed retrospectively.Results In 160 premature infants,brain injury occurred in 76 cases,the incidence of brain injury was 47.5％.Ischemic lesions were seen more in brain injury in premature infants,cerebral white matter injury was the most common,especially periventricular leukomalacia.Ischemic brain injury performed patchy or large sheet increased signal intensity on T1-weighted images(T1 WI),decreased signal intensity on T2-weighted images (T2WI) and obviously increased signal intensity on diffusion weighted imaging (DWI) in half egg circle center and around the lateral ventricle.Periventricular leukomalacia performed patchy decreased signal intensity on T1WI,increased signal intensity on T2WI and decreased signal intensity on DWI.Periventricular-intraventricular hemorrhage was seen more in hemorrhagic lesions.Hemorrhage stove was performed different signal because of different bleeding time.MRI performance in acute phase was iso-signal or slightly decreased signal intensity on T1WI,increased signal intensity on T2WI,increased signal intensity on T1WI,slightly decreased signal intensity on T2WI in early subacute,increased signal intensity on T1 WI and T2WI in late subacute and obviously decreased signal intensity on magnetic sensitive weighted imaging.The detection rate of ischemic lesions by DWI was higher than the conventional MRI,and DWI could show cerebral white matter damage of premature infants much earlier than the conventional MRI.The detection rate of hemorrhage stove by susceptibility weighted imagingc (SWI) was higher than the conventional MRI (x2 =23.78,P ＜ 0.05),and SWI could show hemorrhagic lesions much earlier than conventional MRI (x2 =27.02,P ＜ 0.05).Conclusions MRI,especially combined multiple sequence checking,could provide accurate imaging evidence for the early diagnosis of brain injury in premature infants.
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Objective To study magnetic resonance imaging(MRI) features of dysembryoplastic neuroepithelial tumor(DNT) and to improve accurate diagnosis of DNT.Methods The MRI appearance and clinical features of 10 patients with DNT confirmed by surgery and pathology were analyzed retrospectively.Results In 10 cases,9 tumors located in supratentorial hemisphere cortex,3 tumors located in the temporal lobe,5 in the frontal lobe,1 in the parietal lobe,and 2 of them encroached the adjacent white matter.In 9 tumors located in supratentorial hemisphere cortex,8 cases had decreased signal intensity on T1-weighted MR images,1 case iso-decreased mixed signal intensity on T1-weighted MR images,and 9 cases increased signal intensity on T2-weighted images,9 cases slightly increased signal intensity on fluid attenuated inversion recovery weighted images.The manifestation of tumors was cystic or cystic partially oriented and was seen separate section intratumoral in some cases.Three cases appeared as hyperintense ring sign and internal septation,2 cases appeared as a triangle in shape,3 cases appeared as gyms-like shape,and 1 case as round shape,similar to cyst.Nine tumors had no significant mass effect and peritumoral edema.Enhanced MR imaging showed only 1 case with slight and heterogeneous enhancement,the rest 6 cases showed non enhancement.One case located in cerebellar hemisphere,and appeared cystic-solid mass,the solid part had decreased signal intensity on T1-weighted MR images,and increased signal intensity on T2-weighted images,the cystic part had decreased signal intensity on T1-weighted MR images,and increased signal intensity on T2-weighted images.On enhanced MR imaging,the wall-node obviously contrast enhancement,cyst wall slightly contrast enhancement,cystic part non enhancement.The tumor had peritumoral edema and mass effect.Ten cases had no hemorrhage and calcification.Conclusion The MRI appearance of DNT is characteristic and is helpful for the preoperative diagnosis of DNT.
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BACKGROUND: Elimination of antigenic substances from natural extracellular matrix with the integrity of the tissue structure retained renders the matrix to possess better biocompatibility and provides a cell culture environment close to conditions of the internal environment. Such materials are the primary choice for cell culture scaffold in tissue engineering.OBJECTIVE: To prepare human articular cartilage acellular matrix so as to provide a methodological basis for further study of articular cartilage acellular matrix as cell scaffold materials.DESIGN: A single sample study of bone tissues.SETTING: The experiment was performed in Institute of Orthopedics, General Hospital of PLA, between January and May in 2004. The specimens were obtained from patients requiring joint replacement for femoral neck fracture.MATERIAIS: The experiment was conducted in the Department of Orthopedics, General Hospital of PLA from January to May in 2004. Human articular cartilage specimens were obtained from the femoral head of patients with total hip arthroplasty for femoral neck fracture.METHODS: Totally 10 specimens of fresh articular cartilage(3.5 mm × 4. 5 mm × 2.0 mm) were obtained and freeze-dried for 12 hours. Cartilage acellular matrix was prepared using Triton X-100, Dnase and Rnase and identified by means of hematoxylin-eosin(HE) and safranine O staining and immunohistochemical staining for cartilage proteoglycan.MAIN OUTCOME MEASURES: Histological observation of the articular cartilage acellular matrix and immunohistochemical staining of cartilage proteoglycan.RESULTS: HE and safranine O staining both showed no cellular structure in the matrix with only recesses left by the removed cells. Immunohistochemical staining for cartilage proteoglycan yielded positive results, suggesting the presence of cartilage proteoglycan in the acellular matrix.CONCLUSION: Human articular cartilage acellular matrix can be prepared using the modified four-step procedures with detergent and enzymatic extraction with lyophilization, and the preserved cartilage proteoglycan in the material may retain good pressure resistance.
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Objective To develop a method to prepare human articular cartilage derived microcarrier for both rapid propagating chondrocytes and being used as scaffold to support chondrogenesis. Methods Human articular cartilage was crushed into small pieces by muller after lyophilization, and sorted through two different meshes to collect only those specimens measuring 150-200 microns. Then, in turn, the specimens were subjected to 0.25% trypsin at 37 ℃ for 24 hours and 1% Triton X-100 for 72 hours, respectively. The specimens were observed by inverted phase contrast microscopy, and assessed by staining with haematoxylin-eosin, safranin-O (for GAG), as well as by the immunohistochemistry of aggrecan, collagen type Ⅱ. The microcarriers were seeded with human chondrocytes after being irradiated by 60Co. Results Using inverted phasecontrast microscope, the freezing-dry cartilage particles were observed as yellow, different shapes, and their surfaces were uneven, and with many pits. After treating with trypsin and Triton X-100, the microcarriers showed light yellow, without cartilage morphology. The microcarriers became flocculous or like a hairbrush, and the area of contacting surface significant increased. After culture with cartilage cell for 2 hours, lots of spherical chondrocytes adhered to the microcarriers. HE stain of section confirmed that the celluar constituents of the specimens were removed, the specimens stained weakly positive for GAG, negatively for aggrecan, and positively for collagen type Ⅱ, respectively. Conclusion The detergent and trypsin can remove the cellular constituents and knock out the aggrecan from human articular cartilage while maintaining collagen type Ⅱ and GAG, and made the cartilage pieces flocculous or hairbrush-like. The chondrocytes can be well maintained in human articular cartilage derived microcarriers. Human articular cartilage derived microcarriers were prepared successfullly.
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Objective To evaluate the characteristics of remodeling of Achillis tendon under different training methods, including the functional and structural changes in its insertion, and to extend these experimental findings to improve strategies of prevention of military training injuries. Methods With a special equipment to provoke running and jumping, adult rabbits were trained under different loads and the length of time, then the Achillis tendons were harvested. The tendons and their attachment were examined with light and scanning electron microscopy, as well as analyzed biomechanically. Results The findings showed that the structure of tendon became weak at the fourth week of excessive exercise, as evidenced by changes in micro-structures. Conclusion Excessive load is the major cause of enthesiopathy of the Achillis tendon, and training in cycles may have positive effects in prevention of the pathology.