Application of brain organoids in environmental toxicology / 环境与职业医学

Since the 19th century, the emergence of model systems has helped researchers further understand cellular signaling pathways, identify potential drug targets, and conduct environmental toxicological studies. Exogenous chemicals, such as pollutants, drugs, and industrial chemicals, may affect brain biological processes and functions and eventually lead to neurological diseases. However, the brain is a complex and well-organized human organ, which is fundamentally different from any existing model system. Animal models may not be able to completely simulate the human brain in testing the neurotoxicity of environmental pollutants due to species differences. Human brain organoids, generated from human pluripotent stem cells, are emerging model systems for neurotoxicological research in line with the real situation of human body at the level of genome, transcriptome, and metabolome, and provide an effective platform for testing neurotoxicity of environmental toxins. We reviewed the latest development of brain organoids technology and its application in the evaluation of environmental neurotoxins, and provided new insights into the application of brain organoids in environmental neurotoxicology.

Bayesian network analysis of long-term oncologic outcomes of open, laparoscopic, and robot-assisted radical cystectomy for bladder cancer.

BACKGROUND: To understand the long-term oncologic outcomes of open radical cystectomy (ORC) versus laparoscopic radical cystectomy (LRC) versus robot-assisted radical cystectomy (RARC) for bladder cancer (BCa). Therefore, we performed the conventional meta-analysis and network meta-analysis to evaluate the long-term oncologic outcomes of ORC, LRC, and RARC for BCa. METHODS: A systematic search of PubMed, Embase, Cochrane Library, Medline, and Web of science was performed up until July 1, 2021. Long-term oncologic outcomes include the 5-year overall survival (OS) rate, the 5-year recurrence-free survival (RFS) rate, and the 5-year cancer specific-survival (CSS) rate. The Bayesian network analysis has been registered in PROSPERO (CRD42020208396). RESULTS: We found that 10 articles (including 3228 patients) were included in our Bayesian network analysis. No significant differences were found between ORC, LRC, and RARC in long-term oncologic outcomes in either direct meta-analysis or network meta-analysis. Therefore, the clinical effects of 5-year OS, RFS, and CSS of RARC, LRC, and ORC are similar. But LRC may be ranked first in 5-year OS, RFS, and CSS compared to other surgical approaches by probabilistic analysis ranking via Bayesian network analysis. CONCLUSION: We found that there were no statistical differences in the 3 surgical approaches of RAPC, LPC, and OPC for Bca in long-term oncologic outcomes by direct meta-analysis. However, Subtle differences between these surgical approaches can be concluded that LRC may be a better surgical approach than RARC or ORC in long-term oncologic outcomes by probabilistic analysis ranking via Bayesian network analysis. Moreover, we need a large sample size and more high-quality studies to improve and verify further.

Biomechanical properties of a novel automatic anti-rotation posterior atlantoaxial internal fixation system: a finite element analysis / 中国组织工程研究

BACKGROUND: Atlantoaxial posterior approach is currently the main surgical treatment for atlantoaxial instability and/or dislocation, but the shape of rod in normal screw-rod device system is cylindrical. To obtain satisfactory reduction of atlantoaxis, the rod will be pre-bent obviously before fixation; however, the cylindrical rod will be rotated when tighten the nuts. Extra devices will be required to adjust and maintain the direction of the rod, thereafter, the surgical field will be blocked by the device, and spinal injury will occur once the devices are not held tightly. While the novel automatic anti-rotation rod has the function of anti-rotation during nut-tightening process, and also holds all the advantages of normal rod. Further research should be performed for the differences in biomechanical characteristics between two methods.OBJECTIVE: To investigate the biomechanical properties of the novel automatic anti-rotation rod for internal fixation system of atlantoaxial posterior approach based on three-dimensional finite-analysis model of upper cervical spine.METHODS: The three-dimensional finite element model of upper cervical spine with internal rod fixation system was developed. The biomechanical characteristics of the internal fixation system were analyzed. RESULTS AND CONCLUSION: The traditional and novel three-dimensional finite element model with realistic and geometric similarity contained 198330 elements, 964747 nodes and 246788 elements, 996069 nodes,correspondingly. There was no obvious stress concentration in both two systems, stress was concentrated mainly in the screw-bone and screw-rod interfaces. The stress values of the novel system were higher than those of the traditional system, but the maximum Von Misses Stress of two systems was lower than the yield (795-827 MPa ) and ultimate (860-896 MPa) strength of titanium alloys. These results show that the design of the novel automatic anti-rotation rod-screw fixation system has matched the biomechanical requirements for new internal fixation instruments, and is one safe, effective and practical device for atlantoaxial posterior procedure showing promising application prospect.