[Spinal cord magnetic resonance imaging: methods and applications].

Spinal cord magnetic resonance imaging (MRI) is an advanced imaging technique (mainly in the cervical cord) and has been gradually used in basic scientific research such as human sensation and motor function, and clinical applications such as spinal cord injury, myelitis, and chronic pain, etc. The development of spinal cord MRI is still at the early stage compared with brain MRI and limited by the current MRI technology and data analysis methods. This review focuses on the methods and applications of spinal cord MRI technology in the basic research fields of cognitive neuroscience and clinical application. Firstly, we will introduce the imaging principle, methods, measurement standards, and applications of most commonly used multimodal spinal cord MRI techniques, including quantitative spinal cord MRI (such as structural, diffusion, spectroscopy, myelin water, magnetization transfer, and chemical exchange saturation transfer imaging, etc.) and spinal functional MRI (fMRI). Secondly, we will discuss the technical challenges and possible solutions of spinal cord MRI data processing from the three dimensions of denoising, data processing pipeline optimization, and repeatability and reliability. Finally, we will discuss the application status and development prospects of spinal cord MRI.

[Analysis of Proliferation Characters of Bone Marrow Mesenchymal Stem Cells Derived from Patients with Myelodysplastic Syndrome].

OBJECTIVE: To analyze the proliferation potential of bone marrow-derived mesenchymal stem cells (MSC) in patients with myelodysplastic syndrome (MDS). METHODS: The MSC derived from the 24 patients with newly diagnosed MDS (MDS-MSC group) and MSC derived from 15 patients with nutritional anemia (control group) in the Affiliated Hospital of Hebei University were used as the research objects. The proliferation potential of MSC was analyzed by colony-forming unit assay, doubling time, cumulative passaging, cell number after 10 days of culture with equal amount of MSC and MTT experiment. The mechanism of abnormal proliferation was analyzed by cell cycle experiment, apoptosis experiment and p21 gene expression assay. RESULTS: In the colony forming unit assay, the number of MDS-MSC colonies was 4.44±2.51, which was significantly lower than that of the control group (12.44±2.55)(P<0.01); the doubling time of MDS-MSC group was significantly longer than that of the control group (7.80±3.26 vs 3.63±0.85) (P<0.01); the number of MDS-MSC in 5×104 culture for 10 days was (39.40±14.18)×104, which was significantly lower than that of the control group ï¼»(85.30±9.49)×104 ï¼½(P<0.01); the number of cumulative passages in MDS-MSC group was 5.20±1.40, which was significantly lower than that in control group (11.60±1.96)(P<0.01); MTT results showed that the proliferation capability of MSC in MDS-MSC group was lower than that in the control group. The cell proportion of G0/G1 phase in MDS-MSC group was higher than that in the control group, while the cell proportion of S phase was lower (P<0.05). The percentage of early apoptotic cells in MDS-MSC group was higher than that in control group (P<0.05); the relative expression level of p21 mRNA in MDS-MSC group was significantly higher than that in control group(P<0.01). CONCLUSION: The proliferative capability of MDS-MSC is significantly reduced, which relates with the arrest of cell cycle in G0/G1 phase, the increase of early apoptotic cells and senescent cells of the MDS-MSC.

Effect of floral cluster pruning on anthocyanin levels and anthocyanain-related gene expression in 'Houman' grape.

Lateral floral clusters were removed from the main axis of the floral clusters of 'Houman' grape plants, leaving only 3-5-cm-long region of flowers at the end of the central axis. The floral clusters were pruned at 7 days prior to flowering. The effect of the pruning on fruit quality was assessed by determining the composition and levels of anthocyanins in the fruit and anthocyanin-related gene expression. Results indicated that floral cluster pruning significantly improved the quality of the fruit by increasing berry size, fruit weight and the total content of soluble solids. Floral cluster pruning also decreased the level of titratable acidity. Sixteen different anthocyanins were detected in fruit of the pruned clusters, while only 15 were detected in fruit from unpruned clusters. The level of anthocyanins was also significantly higher in fruit of the pruned clusters than in the unpruned clusters. Anthocyanin-related gene expression was also significantly upregulated to a higher level in fruit from pruned floral clusters as compared with unpruned clusters. The upregulation was closely associated with increases in anthocyanin biosynthesis.

A subject-specific pelvic bone model and its application to cemented acetabular replacements.

A subject-specific three-dimensional finite element (FE) pelvic bone model has been developed and applied to the study of bone-cement interfacial response in cemented acetabular replacements. The pelvic bone model was developed from CT scan images of a cadaveric pelvis and validated against the experiment data obtained from the same specimen at a simulated single-legged stance. The model was then implanted with a cemented acetabular cup at selected positions to simulate some typical implant conditions due to the misplacement of the cup as well as a standard cup condition. For comparison purposes, a simplified FE model with homogeneous trabecular bone material properties was also generated and similar implant conditions were examined. The results from the homogeneous model are found to underestimate significantly both the peak von Mises stress and the area of the highly stressed region in the cement near the bone-cement interface, compared with those from the subject-specific model. Non-uniform cement thickness and non-standard cup orientation seem to elevate the highly stressed region as well as the peak stress near the bone-cement interface.