By using Urist s method four types of BMG from the long bones of the rabbit、 pig、sheep、 and human being were prepared. Each of them was implanted into the pectoralis and thigh muscles in 25 adult rats, respectiely. Two-eight weeks after implantation, the unoreaction and inductive osteogensis potential in the tissues were observed under mieroscope. The result showed that aBMG had inductive osteogenesis potential. However, rejection in varying digree existed around aBMG. It was important to further decrease the antingenicity digree exised around a BMG . and enhance its osteogennic potential before the possibility of its clinical application.
Objective To set up the experimemtal model with superior segmentalbone defect in acetabulum and implant the three-fin acetabular component, and examine the Von Mises stresses of pelvis bone with simulating single leg position in vitro using rosette strain gages method(RSGD). Methods Four kinds of three-fin components were made based on measurement of diameter, depth and roof thickness of acetabular specimens. These kinds of threefin acetabular components based on spreaded degrees of lateral fins(0,36,45 and 60°). The superiorsegmental bone defect of acetabulum in 4 cadaver pelvis specimens was made,then simulated the actual position to place implant into acetabular bone.A blank control group was set up.After being fit up the 7 sets of rosette strain gages,then specimen to test the pelvic Von Mises stresses simulating the static load of single leg on the mechanic machine.Progressive load was graded into 150, 300,450, 600, 750 and 900 N.We obtained the strains informations about loaded andun-loaded pelvis bone. Results Based on computed the strains informations,we were informed the Von Mises stresses about pelvis bone.The maximal Von Mises stresses of selected local position was 6.93 MPa and the minimal Von Mises stresses of selected local position was 1.08 MPa. Conclusion Providing the data about the mainpart of threefin acetabular component to optimize spreaded degrees of lateral fins.
ObjectiveTo establish multidrugresistance cell substrain of human hepatocellular carcinoma and to investigate its characteristics.MethodsSMMC7721 cell strain was cultured in Adriamycin(ADM). The multidrugresistance cell substrain SMMC7721/ADM was harvested after a long period of culture by gradually increasing the concentration of ADM and its characteristics were investigated. Results①The drug resistance of SMMC7721/ADM to ADM increased by 33.3 times, to Vincristine 16.8 times, to Diamminedichloroplatinum 2.8 times. ②The drug resistance cell substrain had almost the same growth velocity as its parental generation. The doubling time was 32.0 hours and 30.5 hours respectively. They had the analogous growth curves. ③The obvious difference between the drug resistance cell substrain and its parental generation was that the former’s microvilli became thick, short and scattered by scanning and transmitting electron microscopy. ④The multidrug resistance cell substrain kept the characteristics of hepatocellular carcinoma, it could be transplanted into the subcutaneous tissue of nude mice. ⑤The drug resistance of the cell substrain reduced to 28.0% and 9.2%after removal of the drug for 1 month and 2 months respectively, its drug resistance could remain stable (35.4 times) after 2 months of culture in ADM (0.04 μg/ml).ConclusionThe SMMC7721/ADM cell substrain has the stable fundamental characteristics of a drug resistance cell strain.
Percutaneous pulmonary puncture guided by computed tomography (CT) is one of the most effective tools for obtaining lung tissue and diagnosing lung cancer. Path planning is an important procedure to avoid puncture complications and reduce patient pain and puncture mortality. In this work, a path planning method for lung puncture is proposed based on multi-level constraints. A digital model of the chest is firstly established using patient's CT image. A Fibonacci lattice sampling is secondly conducted on an ideal sphere centered on the tumor lesion in order to obtain a set of candidate paths. Finally, by considering clinical puncture guidelines, an optimal path can be obtained by a proposed multi-level constraint strategy, which is combined with oriented bounding box tree (OBBTree) algorithm and Pareto optimization algorithm. Results of simulation experiments demonstrated the effectiveness of the proposed method, which has good performance for avoiding physical and physiological barriers. Hence, the method could be used as an aid for physicians to select the puncture path.
Quantitative measurement of strain distribution of arterial vessel walls due to pulsatile blood flow within the vascular lumen is valuable for evaluating the elasticity of arterial wall and predicting the evolution of plaques. The present paper shows that the three-dimensional (3D) strain distribution are estimated through uni-directional coupling for 3D vessel and blood models reconstructed from intravascular ultrasound (IVUS) images with the computational fluid dynamics (CFD) numerical simulation technique. The morphology of vessel wall and plaques as well as strain distribution can be visually displayed with pseudo-color coding.
Objective To investigate whether the biomechanical effect of mushroom shaped surface prosthesis on femoral neck is in the scope of safety after the replacement. Methods Four donated fresh-adult specimens of upper femur under the age of 55 years old were used. The strains of detecting points A (lateral) and B (medial) on the narrow place of femoral neck in the standing position were simulated for three stages before or after the prosthesis replacement, namely the pre-replacement, the initial stage during which the interspace of the prosthesis was filled with cancellous bone, and laterstage during which the interspace of the prosthesis was filled with bone cement. Then they were compared by using l inear regression analysis in Excel and rel iabil ity analysis. Results The regression analysis showed that the values of correlation coefficient r were all more than 99% at the different stages, indicating the strain of femoral neck’s cortical bone was proportional to the load and there was no occurrence of the plastic deformation of the femoral neck. For point A, the slope of the trend l ine of strain was 0.671 9 at the pre-replacement stage. The value of the initial stage after replacement was 0.619 2 and its change rate was —7.8%; while corresponding value was 0.662 7 and —1.4% at the later stage after replacement. For point B, the slope of the trend l ine of strain was —1.056 1 at the pre-replacement stage. The value of the initial stage after replacement was — 1.129 2 and its change rate was 6.9%; while corresponding value was —1.085 1 and 2.7% at the later stage after replacement. Conclusion The mechanical strength of femoral neck is in the scope of safety after surface replacement of the femoral head. The change rate of strain at the later stage is smaller than the initial stage.
Mouse animal models are the most commonly used experimental tools in scientific research, which have been widely favored by researchers. The animal model of mouse leukemia appeared in the 1930s. During the past 90 years, researchers have developed various types of mouse leukemia models to simulate the development and treatment of human leukemia in order to promote effectively the elucidation of the molecular mechanism of leukemia' development and progression, as well as the development of targeted drugs for the treatment of leukemia. Considering that to myeloid leukemia, especially acute myeloid leukemia, there currently is no good clinical treatment, it is urgent to clarify its new molecular mechanism and develop new therapeutic targets. This review focuses on the various types of mouse models about myeloid leukemia used commonly in recent years, including mouse strains, myeloid leukemia cell types, and modeling methods, which are expected to provide a reference for relevant researchers to select animal models during myeloid leukemia research.
We aimed to establish an optical coherence tomography (OCT) system to measure the strain of blood vessels. A general OCT system was constructed firstly and its reliability was confirmed by comparing the OCT imaging of the porcine coronary and the corresponding histological slices. The strain of the porcine coronary was induced by static flow pressure and correlation algorithm was used to calculate the strain field of blood vessels within OCT images. The results suggest that bright-dark stratification of blood vessels displayed in OCT images is consistent with the intima and media layers of histological image. Furthermore, the strain of media layer is greater than that of the intima layer under the same static pressure. The optical coherence imaging system could not only measure the histological structure of the blood vessels, but also qualify the vessel strain under flow pressure.
Bone marrow-derived mesenchymal stem cells (BMSCs) are multipotent stem cells that differentiate into a variety of cell types and widely used in tissue regeneration engineering. The purpose of this study is to investigate whether the cyclic biaxial stretching strain could promote the rat BMSCs (rBMSCs) to differentiate into cardiomyocyte-like cells in vitro. The second or third generation of rBMSCs were randomly divided into the cyclic stretching stain group, the control group and the blank group. Those rBMSCs in the cyclic stretching strain group were seeded on a silicone membrane with complete medium were exposed to biaxial stretching strain of 10% of membrane at a frequency of 1 Hz lasting for 6 h, 12 h and 24 h. Those in the control group were seeded on silicone membrane with complete medium. Those in the blank group were seeded in the 6-wells plates with complete medium. The mRNA expression of GATA4 and myocyte-specific enhancer factor 2C (MEF-2C) were detected by the real-time fluorescent quantification PCR and the protein expression of connexin 43 (Cx43) was detected by using the Western blot method. The results showed that the mRNA expression level of the GATA4 and MEF-2C, and the protein expression level of Cx43 were significantly higher in the cyclic stretching strain groups, compared with those in the relative control groups (P<0.05). It suggests that cyclic biaxial stretching strain could play a part in the induction of rBMSCs to differentiate into cardiomyocyte-like cells in vitro, but the differentiation mechanism is still unclear.
Objective By observation of the diameter, progression rate, wall thickness, and the opening angle of the abnormal aortic of abdominal aortic aneurysm (AAA) in rats, to observe the effect of saturated hydrogen saline on residual strain of AAA rats, and to investigate its inhibition effect on AAA formation. Methods Twenty healthy male Sprague Dawley rats (weighing, 200-220 g) were randomly divided into 2 groups, which was made the AAA model by infiltration of the abdominal arota with 0.5 mol/L calcium chloride. Saturated hydrogen saline (5 mL/kg) or saline (5 mL/kg) was injected intraperitoneally in the experimental group or control group respectively, every day for 28 days. At 28 days, the diameter, progression rate, wall thickness, and opening angle of the abnormal aorta were mearsured. The aortic tissue was harvested for histological examination (HE staining and aldehyde-fuchsin staining). Results At 28 days after operation, the diameter of abnormal aorta in 2 groups were significantly higher than preoperative ones (P lt; 0.05), the progression rate in experimental group (65% ± 15%) was significantly lower than that in control group (128% ± 54%) (t=3.611, P=0.005). The opening angle and the wall thickness in experimental group were (88.78 ± 29.20)° and (0.14 ± 0.03) mm respectively, had significant differences when compared with the values in control group [(44.23 ± 28.52)° and (0.36 ± 0.05) mm respectively] (P lt; 0.01). The integrity and continuity of the aortic wall in experimental group were superior to that in the control group. Compared with the control group, the injury of elastic fiber in aortic wall and the infiltration of inflammation were all reduced. Conclusion Saturated hydrogen saline can maintain good mechanical properties and reduce dilatation of the aorta by increasing residual strain and reducing the remodeling of it.