ABSTRACT
Objective:To discuss the surgical strategies of atlantoaxial dislocation in children with mucopolysaccharidosis IVA.Methods:8 cases of atlantoaxial dislocation in children with mucopolysaccharidosis IVA treated with posterior atlantoaxial reduction, decompression, bone graft and internal fixation from April, 2019 to October, 2020 were retrospectively analyzed, including 6 males and 2 females, aged 6.2±3.1 years (range, 2-10 years). All the 8 children had lower limb weakness and walking instability, and some of them could not even stand and walk, and all of them had odontoid hypoplasia, atlantoaxial dislocation and systemic skeletal dysplasia. Measures, including American Spinal injury Association (ASIA) grade, modified atlanto-dental interval (mADI) and reduction rate, screw placement type and fusion of bone graft, were recorded and analyzed.Results:The follow-up time was 17.8±7.4 months (range, 8-27 months). The total operation time was 144.0±43.1 mins (range, 90-220 min) and the blood loss during the surgery was 89.1±55.1 ml (range, 15-180 ml). The ASIA grade were 3 cases of "C" level, 4 cases of "D" level and 1 case of "E" level before the operation, and 1 case of "C" level, 1 case of "D" level and 6 cases of "E" level at the latest follow-up. The mADI reduced from 7.38±2.62 mm pre-surgery to 2.50±1.60 mm ( t=5.71, P=0.001). The reduction rate of the latest follow-up mADI was 65.0%±26.3%. 31 pedicle screws were inserted, including 26 Type I screws (83.9%), 4 Type II screws (12.9%) and 1 Type III screw (3.2%), and no injury of spinal cord or blood vessels were observed associated with the Type III screw. One unilateral axial lamina screw was used in 1 case. 5 patients showed fusion (autogenous bone) 6 months after the surgery, 2 patients got fusion (allogeneic bone) 1 year after the surgery, and other patients showed bone graft resorption (allogeneic bone) at the latest follow-up. One patient developed type II respiratory failure on the night of operation and recovered after rescue. Other patients had no complications such as vascular and nerve injury, screw loosening and so on. Conclusion:The majority of children with type IVa mucopolysaccharidosis are accompanied by absence of odontoid process. If such children are complicated with atlantoaxial dislocation and cervical spinal canal stenosis resulting in cervical spinal cord injury, timely surgical intervention should be carried out. Posterior atlantoaxial fusion is a safe and effective surgical method. As children have the characteristics of multi-system involvement, multi-disciplinary cooperation may be needed to ensure perioperative safety.
ABSTRACT
Objective:To study the protective anti-radiation effect of inhibiting CD47 expression in the lung tissues of mice and to explore the associated mechanism.Methods:Female C57BL/6 mice ( n = 60) were randomly divided into four groups: normal, blank, negative and positive. The blank group received only whole-lung irradiation; The negative group received whole-lung irradiation and tracheal infusion of adeno-associated virus containing nonsense sequence shRNA; The positive group received whole lung irradiation and tracheal drip containing adeno-associated virus containing shRNA expression of CD47. Fresh blood samples were collected at 24 h, 4 weeks, and 12 weeks post-irradiation, respectively. The expression level of CD47 mRNA was determined by RT-PCR. Determination of hydroxyproline content by alkaline hydrolysis. The LC3 expression level was measured by immunohistochemical staining. Serum transforming growth factor-β 1 (TGF-β 1) and tumor necrosis factor-α (TNF-α) levels were assessed by ELISA. Results:RT-PCR showed that the relative expression level of CD47 mRNA in the lung tissues in the positive group was significantly lower compared to those in the negative group, the normal group, the blank group (24-hour, P were <0.001,<0.001,<0.001, respectively. 4-weeks, P were <0.001,0.003,0.001, respectively. 12-weeks, P were 0.009, 0.002, 0.005, respectively). There were no significant differences in CD47 mRNA expression in the three groups except the positive group (all P>0.05), and there was no significant difference in CD47 mRNA expression with time in each group (all P>0.05).The serum TGF-β1 content was higher in the 24 h, 4-week, and 12-week blank groups ( P were <0.001, 0.003 and 0.003, respectively) and negative groups( P were 0.001, 0.021 and 0.034, respectively) after irradiation than that in the mice in the normal group. At the same time, the serum TNF-α of positive group after irradiation (24 hours, 4 weeks, 12 weeks, P were 0.022, <0.001, <0.001, respectively) were significantly higher than those of the normal group. The content of hydroxyproline in the blank group was significantly higher than that in the normal group (4 weeks, 12 weeks, P were 0.002, <0.001, respectively). Immunohistochemical indications: 24 h after irradiation was higher than the expression of LC3 in mouse lung tissue at 4 weeks and 12 weeks (all P < 0.001). The difference between the negative group and the blank group was not obvious ( P>0.05). Conclusions:Inhibition of CD47 expression can reduce the degree of radiation-induced pneumonia and pulmonary fibrosis probably via enhanced autophagy. CD47 may represent a novel target for the protection of radiation-induced lung injury.