As an important member of tool enzymes, exonuclease is a kind of hydrolytic enzymes without strict base sequence dependent. In recent years, by taking advantage of different hydrolysis ways of exonuclease and nanotechnology, cycle effect of enzyme digestion, aptamer, non Watson-Crick base pairing system by metal ions, fluorescent nucleic acid probes, electrochemical methods etc. , a series of exonuclease-assisted signal amplification strategies have been developed, which played a very key role in improving the sensitivity of detection methods. Therefore, exonuclease has been widely used in high sensitive detection of nucleic acids, proteins, ions, small molecules and so on. To understand it better and apply it well in the future, the application progress of exonuclease-assisted signal amplification strategies in biochemical analysis has been summarized in this review.

BACKGROUND:Because of complicated biomechanics of lumbar vertebra, mast facet osteoarthritis, degenerative joint disease and vertebral subluxation usual y occur fol owing lumbar fusion. To avoid adjacent segment disease, researchers have transformed strong internal fixation into elastic fixation, but the treatment outcomes are barely satisfactory. Furthermore, factors involving adjacent segment disease remain unclear. OBJECTIVE:To explore the relationship between L3-4 segment disease fol owing lumbar fusion and gender. METHODS:200 patients undergoing lumbar fusion of L4-5 and L5-S1 in the First Hospital of Shijiazhuang ranging from 2007 to 2016 were enrol ed, and then al otted into male and female groups (n=100 per group) for retrospective analysis. The incidence of L3-4 segment disease was compared between two groups. RESULTS AND CONCLUSION:Compared with the male group, in the female group, the incidence of L3-4 segment diseases at different fusion locations and ranges, the Oswestry disability index and visual analogue scale and each migration range were significantly higher. Logistic regression analysis showed that gender was one of the independent factors of L3-4 segment disease following lumbar fusion of L3-4 and L5-S1. These findings suggest that gender is one of the influencing factors of L3-4 segment disease after instrumented lumbar;thereby, adjacent segment disease occurs frequently in female patients.

Objective:To analyze the application and clinical efficacy of one-stage unilateral or bilateral fenestration, debridement, interbody fusion combined with posterior internal fixation for the treatment of lumbosacral brucellosis spondylitis.Methods:All patients with lumbosacral brucellosis spondylitis were retrospectively analyzed, who underwent fenestration, debridement, interbody fusion combined with posterior internal fixation from June 2013 to June 2019. A total of 48 patients were enrolled in this study. According to the surgical method, they were divided into two groups. Unilateral fenestration group: 27 cases of one-stage posterior unilateral fenestration, debridement, interbody fusion combined with posterior internal fixation were performed, 21 males and 6 females, aged 23-71 years; Bilateral fenestration group: 21 cases of one-stage posterior bilateral fenestration, debridement, interbody fusion combined with posterior internal fixation were performed, aged 26-58 years. There were 16 males and 5 females. The preoperative and postoperative clinical symptoms, neurological function, C-reactive protein, the surgery duration time, the blood loss, and erythrocyte sedimentation rate were observed. The internal fixation device was evaluated for looseness or fracture by imaging examination. The Bridwell classification criteria were used to evaluate the bone graft fusion. Postoperative complications were also assessed.Results:All patients completed the operation successfully, and the diseased tissues were sent for pathological examination during the operation, and all of them were diagnosed as brucellosis. All patients were followed up for 12-48 months (mean 23.7 ±6.3 months). C-reactive protein, erythrocyte sedimentation rate, Visual Analogue Scale (VAS), Oswestry Disability Index (ODI) and Japanese Orthopaedic Association Scores (JOA) were significantly improved in both groups at different time points after operation. There was no significant difference in the general condition before operation between the two groups ( P>0.05). The mean operation time and mean blood loss were 120.5±34.1 min and 214.4±150.2 ml, in the unilateral fenestration group; 187.1±30.3 min and 455.8±250.5 ml in the bilateral fenestration group; and the difference was significant ( t=8.123, t=2.962, P<0.05) . The postoperative lumbar and leg pain were significantly relieved. There was no significant difference in C-reactive protein, erythrocyte sedimentation rate, VAS, ODI and JOA scores between the two groups at the same time point. In the bilateral fenestration group, one patient developed incision infection half a month after the operation, who underwent debridement and drainage, and finally cured. There was no significant difference in the time of bone graft fusion between the two groups ( t=0.542, P>0.05). At the last follow-up, all the patients were completely fused. Conclusion:Unilateral or bilateral fenestration, debridement and bone graft fusion and internal fixation for the treatment of lumbosacral brucellosis spondylitis can achieve good clinical results, and the former has the advantages of short operation time and low cost.