A developmental biological study of aldolase gene expression in Xenopus laevis

We cloned cDNAs for Xenopus aldolases A, B and C. These three aldolase genes are localized on different chromosomes as a single copy gene. In the adult, the aldolase A gene is expressed extensively in muscle tissues, whereas the aldolase B gene is expressed strongly in kidney, liver, stomach and intestine, while the aldolase C gene is expressed in brain, heart and ovary. In oocytes aldolase A and C mRNAs, but not aldolase B mRNA, are extensively transcribed. Thus, aldolase A and C mRNAs, but not B mRNA, occur abundantly in eggs as maternal mRNAs, and strong expression of aldolase B mRNA is seen only after the late neurula stage. We conclude that aldolase A and C mRNAs are major aldolase mRNAs in early stages of Xenopus embryogenesis which proceeds utilizing yolk as the only energy source, aldolase B mRNA, on the other hand, is expressed only later in development in tissues which are required for dietary fructose metabolism.We also isolated the Xenopus aldolase C genomic gene (ca. 12 kb) and found that its promoter (ca. 2 kb)contains regions necessary for tissue-specific expression and also a GC rich region which is essential for basal transcriptional activity.

Three-dimensional finite element analysis of lumbar vertebra loaded by static stress and its biomechanical significance

Objective： To explore the mechanical behavior of lumbar spine loaded by stress and provide the mechanical basis for clinical analysis and judgement of lumbar spine fracture classification, mechanical distribution and static stress. Methods： By means of computer simulation method, the constructed lumbar spine three-dimensional model was introduced into three-dimensional finite element analysis by software Ansys 7.0. The lumbar spine mechanical behavior in different parts of the stress loading were calculated. Impact load is 0-8000 N. The peak value was 8000 N. The loading time is 0-40 minutes. The values of the main stress, stress distribution and the lumbar spine unit displacement in the direction of main stress were analyzed. Results： The lumbar spine model was divided into a total of 121 239 nodes, 112 491 units. It could objectively reflect the true anatomy of lumbar spine and its biomechanical behavior and obtain the end-plate images under different stress. The stress distribution on the lumbar intervertebral disc （L3-L4） under the axial, lateral flexion and extension stress, and the displacement trace of the corresponding processus articularis were analyzed. Conclusion： It is helpful to analyze the stress distribution of lumbar spine and units displacement in static stress loading in the clinical research of lumbar spine injury and the distribution of internal stress.

Progress in the Application of 3D Printing Technology in Spine Surgery

We are in the midst of exciting advancements in new technologies and innovative research in precision medicine.Among these,3D printing is one of the most frequently seen in clinical orthopaedic settings.This new technique has been adopted in a vast range of applications in spine surgery,such as producing anatomical models,surgical templates,preoperative plans,and spinal implants.Some studies on 3D printing technologies in spine surgery have reported the benefits of this emerging technology with more effective manufacturing,more visualisation for communication,and more precise navigation for screw insertion and osteotomy.In addition,in customised implant design and fabrication processes,3D printing products with anatomical adaptions and complex porous microstructure show some attractive advantages in terms of fit and osteoinductivity.However,there are still some concerns about the safety and feasibility of the application of 3D printing technology in spine surgery.We review the literature on and share our experiences with the application of 3D printing from the beginning of collaborations between doctors and computer-aided design(CAD)designers to the final follow-up of clinical patients.