BACKGROUND:The biomechanical effect of the implant-bone interface is one of the most important factors for bone resorption. The new structure of the periodontal-ligament-like implants may improve the distribution of the interfacial stress. OBJECTIVE:To discuss the effect of the internal structure changes of traditional implants on the cortical bone stress distribution and peak at the implant-bone interface under different occlusal load conditions, so as to provide a theoretical basis for the optimization design and clinical application of new structure implants. METHODS:Two kinds of digital models, new structure implant (model A) and non-threaded cylindrical implant (model B), were established by Pro/ENGINEER software. Variations of the stress peak and stress distribution of implant-bone interface cortical bone area under the same bone and force environment were analyzed using Ansys software. RESULTS AND CONCLUSION: Under a vertical loading, the stress peak under different forces was reduced by 17.54% in model A compared with model B; under a 45° loading, the stress peak of model A was reduced by 2.59% compared with model B, and it showed an evident tendency of high stress area focusing to the buccal side of model B. Under the chew-simulation loading, the stress peak of model A was lower than that of model B. The biggest difference (0.353 2 MPa) appeared atβ=12°(β is the angle of force direction and the implant axis), and it gradualy reduced atβ > 12°. At the same time, model A had a wider range of application degree compared with model B in two quantitative indicators, including optimal peak stress of promoting bone tissue growth and stress peak of maintaining healthy bone tissue. These results suggest that the optimized structure of implants contributes to improve the cortical bone stress distribution at the implant-bone interface, decrease the peak stress, and reduce the risk of cortical bone absorption in a wider range.

Animals ; Arterial Occlusive Diseases ; physiopathology ; therapy ; Dogs ; Genetic Therapy ; Hepatocyte Growth Factor ; genetics ; Hindlimb ; blood supply ; Ischemia ; physiopathology ; therapy ; Male ; Plasmids

BACKGROUND:Alogeneic bone marrow stromal stem cel transplantation for treatment of bone diseases is a hot topic. To seek effective methods for prevention of post-transplantation immune rejection is urgent to be solved.
OBJECTIVE:To explore the expression of MHC antigen on the surface of bone marrow stromal stem cels after osteogenic inductionin vitro.
METHODS:Bone marrow samples were extracted from rabbits to in vitro isolate and culture bone marrow stromal stem cels. Then, the cels were cultured in IMDM medium containing bone morphogenetic protein-2. Flow cytometry was used to analyze the expression of MHC antigen on the osteoblasts differentiated from bone marrow stromal stem cels.
RESULTS AND CONCLUSION:There was highly expressed MHC I antigen but no MHCII antigen on the osteoblasts differentiated from bone marrow stromal stem cels. After osteogenic induction, no immune rejection was found. These findings indicate that alogeneic or xenogeneic bone marrow stromal cel transplantation can be used in the treatment of bone defects.

Objective To evaluate the performance parameters of the PET instrument, which has been used for years in our hospital, assuring the stability of image quality and performance parameters. Methods NEMA NU 2-1994 Standards was used as reference for performance measurement of PET, which were published by National Electrical Manufacturers Association(NEMA). The NEMA standard cylinder model, 18F radiation source, and 18F and 68Ge columniform radiation source were used. Results Projects for performance measurement and daily quality control were drawn up. Conclusion This project provides a reference and methods for the performance measurement of PET instrument and daily quality control. It better ensures the stability of image quality and performance parameters of the PET instrument.

BACKGROUND: Umbilical cord blood mesenchymal stem cells (UCB-MSCs) can differentiate into various types of cells under certain condisions, and easily proliferate in vitro. However, UCB-MSCs have long establishment time and low frequency.OBJECTIVE: To in vitro isolate and culture UCB-MSCs, and induce its differentiation into osteoblasts.DESIGN, TIM E AND SETTING: The in vitro cytological study was performed at the Laboratory of the Medical College of Qingdao University from June 2008 to January 2009.MATERIALS: UCB was obtained from term normal delivery women at the Department of Gynaecology and Obstetrics, Qingdao Municipal Hospital.METHODS: Human UCB-MSCs were isolated and cultured in vitro by Percoll density gradient. When reached 90% confluency,UCB-MSCs were digested by trypsin for subculture. At the third passage, UCB-MSCs at 1×106 were incubated. When reached 50% 60% cenfluency, UCB-MSCs were treated with DMEM supplemented with 0.1 μmol/L dexamathasone, 10 mmol/Lβ-sodium glycerophosphate and 50 μmol/L vitamin C. UCB-MSCs in the control group were incubated in low glucose DMEM.MAIN OUTCOME MEASURES: Growth and proliferation of MSCs were observed under the inverted microscope. Cell surface marker expression and cell growth curve were measured by flow cytometry. Cell ultrastructure was observed under the transmission electron microscope. Differentiation of UCB-MSCs into osteoblasts was determined by Won Kossa staining and alkaline phosphatase staining.RESULTS: Primary cultured UCB-MSCs had similar morphology to bone marrow mesenchymal stem cells. After passage, cell morphology was even, presenting spindle shape. UCB-MSCs at passage 3 highly expressed CD29, CD44, CD13, but did not express CD34. Growth latency was 2-3 days. Cells entered logarithm proliferation phase at days 3-4, and platform phase 1 month later. Nuclei presented round or irregular, with clear nuclear membrane, 1-2 nucleoli, rough chromatin, abundant organelles and microvilli. UCB-MSCs at passage 3 were gradually confluent following 3 days of osteogenic induction, with the presence of pavement-stone shape. 14 days later, calcified nodules by Von Kossa staining, and cells were positive for alkaline phosphatase staining. In the control group, no calcified nodules were found, and cells were negative for alkaline phosphatase staining.CONCLUSION: UCB-MSCs can be successfully isolated by Percoil density gradient, and induced to differentiate into osteoblasts in vitro.

Objective:To identify the cerebral activation patterns associated with the processes that occur during viewing Chinese and English words in native Chinese English learners.Methods:12 right-handed Chinese English hamers were divided into two groups equally,namely English majors and non-English majors,and took semantic judgement tasks of both English and Chinese words,for whom the fMRI images were coUected.Results:To various degrees,all subjects demonstrated activation of associated cerebral regions in both hemispheres and the left hemisphere activation was more significant for most subjects.Except for elassieal regions involved in language processing,such as Wemicke areas and Broca areas,there were other activated cerebral regions,including cerebellum,limbic system and basal ganglia nucleus,etc.To sum up,there were apparent overlap for cerebral activation distribution and no specific processing areas for both tasks.The analysis of ROI(region of interest)suggested that subjects in specialized group were more dependent on right hemisphere to perform English words task.Conclus/on:Language cognition is dominated by left hemisphere,which is also shared by the right hemisphere to various degrees and thus two hemispheres work by ways of both dissociation and coordination.It is possible that working strategy of the right hemisphere in English task is related to proficiency of the second language.A variety of distinctions are shared by each subject for language cognitive patterns.

BACKGROUND:Mechano growth factor has the potential to activate muscle satelite cels and promote myogenic cel growth, and has dual roles in maintaining bone mass and repairing bone defects.
OBJECTIVE: To explore the mechanism underlying osteogenic differentiation of rabbit bone marrow mesenchymal stem cels promoted by the mechano growth factor.
METHODS:The best concentration and time of mechano growth factor to promote osteogenic differentiation of rabbit bone marrow mesenchymal stem cels were detected by MTT. The mRNA and protein expressions of alkaline phosphatase and osteocalcin were detected by qPCR and western blot, respectively. The phosphorylation level of AKT and mTOR were detected by western blot assay.
RESULTS AND CONCLUSION:The best concentration and time of mechano growth factor was 45 μg/L and 5 days for promoting the osteogenic differentiation of rabbit bone marrow mesenchymal stem cels. The expressions of alkaline phosphatase and osteocalcin at mRNA and protein levels were highest after 4-hour intervention with 45 μg/L mechano growth factor, and meanwhile, the phosphorylation levels of mTOR and AKT were also highest. These findings indicate that the mechano growth factor can promote the differentiation of rabbit bone marrow mesenchymal stem cels into osteoblastsvia PI3K/AKT pathway, and its best concentration and time are 45 μg/L and 4 hours, respectively.

Objective To evaluate the early diagnosis value of MRI combined with DSA in cirrhotic nodules (regenerative nodules, dysplastic nodules) becoming small hepatocellular carcinoma. Methods 40 patients diagnosed as cirrhosis and whose liver nodules detected by ultrasound were followed up as MR dynamic study. All patients were followed up by three dynamic contrast-enhanced MR scanning once every 3 months,and the changes of cirrhotic nodules were observed and analyzed in the signal. If MRI suggested cancerous nodules cirrhosis, hepatic artery DSA would be carried out. Results 40 patients were followed up for 1.5 to 3 years,all patients MR nodules were found in liver regeneration. Follow-up process, the dysplastic nodules were founded in 28 cases and the small hepatocellular carcinoma were founded in 18 patients. 16 cases of 18 patients with small hepatocellular carcinoma carried out routine DSA all had typical of hepatic arterial blood supply and angiogenesis, and were given to Integrated Traditional and Western intervention simultaneously. Conclusion Combined use of MRI-DSA in the evaluation of cirrhotic nodules had a definite value, and could find smaller hepatocellular carcinoma,provide the basis for smaller hepatocellular carcinoma therapy.

Objective To observe the effect of early rehabilitation treatment at different time point on the motor function and activity of daily living (ADL) and emotion in acute stroke patients. Methods 120 patients with acute stroke were randomly assigned to three reha-bilitation groups and one control group according to the disease course (3 days, 5 days, 8 days when the disease is steady). Each group con-sisted of 30 eases. The patients in each group were treated with the regular medication therapy, rehabilitation groups were treated with com-prehensive rehabilitation treatment including Bobath technique therapy. Neurological deficit, motor function, balance function, ADL, emo-tion of all the patients were assessed before and 21 days after rehabilitation intervention. Results After treatment, the motor function, bal-ance function, ADL and emotion of each rehabilitation group were improved. The patients'rehabilitation scores in FMA, Fugl-Meyer balance function, MBI and HRSD got much better than that in control group. The difference was statistic significant. The effect of rehabilitation treat-ment did not show difference among rehabilitation groups. Conclusion Early rehabilitation treatment for acute stroke does benefit for stroke patients. Effect does not show vary with the start time of rehabilitation treatment within 8 days after acute stroke.