These results demonstrate that methotrexate can affect homologous recombination repair of DNA double-strand breaks by controlling the expression of homologous recombination-related genes and suppressing the proper assembly of homologous recombination-directed subnuclear foci.

Background Quantitative data on in vivo vertebral disc deformations are critical for enhancing our understanding of spinal pathology and improving the design of surgical materials. This study investigated in vivo lumbar intervertebral disc deformations during axial rotations under different load-bearing conditions. Methods Twelve healthy subjects (7 males and 5 females) between the ages of 25 and 39 were recruited. Using a combination of a dual fluoroscopic imaging system (DFIS) and CT, the images of L3–5 segments scanned by CT were transformed into three-dimensional models, which matched the instantaneous images of the lumbar spine taken by a double fluorescent X-ray system during axial rotations to reproduce motions. Then, the kinematic data of the compression and shear deformations of the lumbar disc and the coupled bending of the vertebral body were obtained. Results Relative to the supine position, the average compression deformation caused by rotation is between + 10% and − 40%, and the shear deformation is between 17 and 50%. Under physiological weightbearing loads, different levels of lumbar discs exhibit similar deformation patterns, and the deformation patterns of left and right rotations are approximately symmetrical. The deformation patterns change significantly under a 10 kg load, with the exception of the L3–4 disc during the right rotation. Conclusion The deformation of the lumbar disc was direction-specific and level-specific during axial rotations and was affected by extra weight. These data can provide new insights into the biomechanics of the lumbar spine and optimize the parameters of artificial lumbar spine devices.

The "sitting position" simultaneously combined anterior-posterior approach is safe and is superior to the traditional prone position and supine position, and the surgical results are satisfactory.

Background The local anatomy of the lumbosacral region of spine is complicated, with special biomechanical characteristics. For surgical management of tuberculous spondylitis reported in the literature, the methods would be two-stage anterior and posterior approaches or one-stage anterior and posterior approach with patient’s intraoperative position being changed. These types of surgery approaches would result in long operative duration and more intraoperative blood loss, and most important there is no coordination between anterior and posterior procedures. Methods The purpose of this study was to introduce a new procedure called in the lateral position single -stage combined anteriorposterior approaches for treatment of lumbosacral tuberculous spondylitis and to evaluate its preliminary surgical outcomes. Fifteen patients with lumbosacral tuberculous spondylitis who underwent single-stage anterior and posterior radical focal debridement and reconstruction in lateral position in our hospital from April 2005 to June 2012 were included in the study. There were 6 males and 9 females with the average age of 46.8 years. The tuberculous lesions involved the following regions: L3-4 in 5cases, L4-5 in 5 cases, L5-S1 in 2 cases, L4 in one case, and L5 in 2 cases. The assessment of surgical outcomes was conducted with clinical symptoms and radiological findings,including operative time, blood loss. deformity angle, Frankel grade and Kirkaldy-Willis evaluation. Results Operation posture: The right lateral position was used for 11 patients and the left lateral position was used for the remaining 4 patients. The average duration of operation for the 15 patients was 270 min. The average intraoperative blood loss was 1720 ml. The mean follow-up period was 4.2 years. There was no recurrence. The postoperative radiological findings showed that the interbody bone grafts were fixed without any dislodgment. There was significant difference between preoperative and postoperative lumbosacral lordotic angles. Kirkaldy-Willis classification rating for the 13 cases with satisfactory results. Conclusion Single-stage combined anterior and posterior surgical management of lumbosacral tuberculous spondylitis with patient in lateral position can achieve radical focal debridement, anterior and posterior procedure coordination and spinal reconstruction.