As one of the most sophisticated research methods of evidence-based medicine, systematic review is an activity of collecting, arranging and analyzing medical information. The methodological characteristics of systematic review reflect the value orientation of this activity. By analyzing and summarizing these characteristics, this paper points that the process of systematic review reflects the value orientation of attaching importance to obtaining universal information sources, treating individual information in an add-weight way, discretion in interpreting results and updating of time-limited information in medical information activities.
The velocity of blood in vessels is an important indicator that reflects the microcirculatory status. The core of the measurement technology, which is based on spatiotemporal (ST) image, is to map the cell motion trace to the two-dimensional ST image, and transfer the measurement of flow velocity to the detection of trace orientation in ST image. This paper proposes a trace orientation measurement algorithm is based on Randomized Hough Transformation and projection transformation, and it is able to estimate trace orientation and flow velocity in noisy ST images. Experiments showed that the agreement between the results by manual and by the proposed algorithm reached over 90%.
ObjectiveTo review the researches of the role of the facet joint orientation (FJO) in degenerative spondylolisthesis (DS). MethodsRelated literature concerning the FJO in patients with DS was extensively reviewed and comprehensively analyzed in 4 terms of the basic concepts, measurement methods, the controversial etiology, and the clinical significance. ResultsThe multiplanar reformation of spiral CT is expected to become a new method of studying the FJO. The causal relationship between the sagittal FJO and DS is still controversial, but further prospective studies are needed to resolve this issue. The sagittal FJO is very important in the prevention of DS and the choice of surgery plan. ConclusionThe etiologic relationship between the FJO and DS need to be further studied.
ObjectiveTo explore the method of acetabular orientation determination in total hip arthroplasty (THA) for bony ankylosed hip and the accuracy of the postoperative evaluation. MethodsBetween January 2009 and March 2013, 33 consecutive patients (49 hips) underwent THA. There were 25 males and 8 females with a mean age of 35.8 years (range, 18-69 years). The left hip was involved in 10 cases, the right hip in 7 cases, and bilateral hips in 16 cases. The causes were ankylosing spondylitis in 18 patients, tuberculosis in 6 patients, traumatic arthritis in 6 patients, osteoarthritis in 2 patients, and suppurative infection in 1 patient. The disease duration was 7-15 years with an average of 10.8 years. The acetabular orientation was determined with periacetabular bone marks (the upper margin of the obturator foramen, acetabular notch etc.) and soft tissue signs (acetabulum transverse ligament etc.). The hip or pelvic radiograph was taken to measure the acetabular prosthesis anteversion and abduction angle, and upward or downward, inward or outward acetabular migration degree. The acetabular anteversion angle of 15 degrees, the abduction angle of 45 degrees, and upward or downward, inward or outward acetabular migration degree of 0 served as a reference value to evaluate the accuracy of acetabular position. ResultsThere was no complications of neurovascular injury, fracture, joint dislocation, and infection. All of patients were followed up 13-63 months (mean, 30.3 months). The anteversion angle and abduction angle were (13.904±4.034)° and (42.898±7.474)° at last follow-up, showing no significant difference when compared with reference value (t=1.386, P=0.178; t=1.969, P=0.055). The inward or outward and upward or downward acetabulum migration degree were (2.530±2.261) mm and (3.886±3.334) mm respectively, showing significant differences when compared with reference value (t=7.830, P=0.000; t=8.159, P=0.000); it was less than 5 mm in 29 hips, 5-10 mm in 18 hips, and more than 10 mm in 2 hips; the acetabulum center coincidence rate was 59.2%. ConclusionFor bony ankylosed hip having loss of normal anatomy structure, intraoperative residues and permanent anatomical structure should be used for acetabular positioning.
ObjectiveTo explore the preparation method, physical and chemical properties, and biocompatibility of a conductive composite scaffold based on polypyrrole/silk fibroin (PPy/SF) fiber with " shell-core” structure, and to provide a preliminary research basis for the application in the field of tissue engineered neuroscience.Methods The conductive fibers with " shell-core” structure were prepared by three-dimensional printing combined with in-situ polymerization. PPy/SF fiber-based conductive composite scaffolds were formed by electrospinning. In addition, core-free PPy conductive fibers and SF electrospinning fibers were prepared. The stability, biomechanics, electrical conductivity, degradation performance, and biological activity of each material were tested to analyze the comprehensive properties of fiber-based conductive composite scaffolds.ResultsCompared with pure core-free PPy conductive fibers and SF electrospinning fibers, the PPy/SF fiber-based conductive composite scaffolds with " shell-core” structure could better maintain the stability performance, enhance the mechanical stretchability of the composite scaffolds, maintain long-term electrical activity, and improve the anti-degradation performance. At the same time, PPy/SF conductive composite scaffolds were suitable for NIH3T3 cells attachment, conducive to cell proliferation, and had good biological activity.ConclusionPPy/SF fiber-based conductive composite scaffolds meet the needs of conductivity, stability, and biological activity of artificial nerve grafts, and provide a new idea for the development of a new generation of high-performance and multi-functional composite materials.
Diffusion tensor imaging technology can provide information on the white matter of the brain, which can be used to explore changes in brain tissue structure, but it lacks the specific description of the microstructure information of brain tissue. The neurite orientation dispersion and density imaging make up for its shortcomings. But in order to accurately estimate the brain microstructure, a large number of diffusion gradients are needed, and the calculation is complex and time-consuming through maximum likelihood fitting. Therefore, this paper proposes a kind of microstructure parameters estimation method based on the proximal gradient network, which further avoids the classic fitting paradigm. The method can accurately estimate the parameters while reducing the number of diffusion gradients, and achieve the purpose of imaging quality better than the neurite orientation dispersion and density imaging model and accelerated microstructure imaging via convex optimization model.
Fibrinogen (Fg) in human plasma plays an important role in hemostasis, vascular repair and tissue integrity. The surface chemistry of extracellular matrix or biological materials affects the orientation and distribution of Fg, and changes the exposure of integrin binding sites, thereby affecting its adhesion function to platelets. Here, the quantity, morphology and side chain exposure of Fg adsorbed on hydrophilic, hydrophobic and avidin surfaces were measured by atomic force microscopy (AFM) and flow cytometry (FCM), then the rolling behavior of platelets on Fg was observed through a parallel plate flow chamber system. Our results show that the hydrophobic surface leads to a large amount of cross-linking and aggregation of Fg, while the hydrophilic surface reduces the adsorption and accumulation of Fg while causing the exposure and spreading of the α chain on Fg and further mediating the adhesion of platelets. Fg immobilized by avidin / biotin on hydrophilic surface can maintain the monomer state, avoid over exposure and stretching of α chain, and bind to the platelets activated by the A1 domain of von Willebrand factor instead of inactivated platelets. This study would be helpful for improving the blood compatibility of implant biomaterials and reasonable experimental design of coagulation in vitro.
Constrained spherical deconvolution can quantify white matter fiber orientation distribution information from diffusion magnetic resonance imaging data. But this method is only applicable to single shell diffusion magnetic resonance imaging data and will provide wrong fiber orientation information in white matter tissue which contains isotropic diffusion signals. To solve these problems, this paper proposes a constrained spherical deconvolution method based on multi-model response function. Multi-shell data can improve the stability of fiber orientation, and multi-model response function can attenuate isotropic diffusion signals in white matter, providing more accurate fiber orientation information. Synthetic data and real brain data from public database were used to verify the effectiveness of this algorithm. The results demonstrate that the proposed algorithm can attenuate isotropic diffusion signals in white matter and overcome the influence of partial volume effect on fiber direction estimation, thus estimate fiber direction more accurately. The reconstructed fiber direction distribution is stable, the false peaks are less, and the recognition ability of cross fiber is stronger, which lays a foundation for the further research of fiber bundle tracking technology.