BACKGROUND: An ideal repairing material characterizes by both great biocompatibility and osteogenesis ability. Any biomaterials should meet excellent biological security and biocompatibility prior to clinical application.OBJECTIVE: To evaluate the biocompatibility and the biological security of the TiO_2-Ag-nano-hydroxyapatite/polyamide66 (TiO_2-Ag-nHA/PA66) composite.DESIGN, TIME AND SETTING: A randomized controlled duplicated design was performed in Chongqing Medical University from July 2008 to July 2009.MATERIALS: A total of 40 Kunming mice aged 3 weeks and of clean grade and 32 healthy adult New Zealand rabbits were provided by Experimental Animal Center of Chongqing Medical University. TiO_2-Ag-nHA/PA66 composite powder (10 g),TiO_2-Ag-nHA/PA66 composites (n=32, 5 mm ×25 mm), and TiO_2-Ag-nHA/PA66 composites (n=32, 3 mm × 5 mm) were provided by Research Center of Nano-Biomaterials of Sichuan University.METHODS: General toxicity test: Forty mice were randomly divided into experimental and control groups. Composite powder was used to prepare leaching liquor which was treated on experimental mice by an intraperitoneal injection. While, an equal amount saline was inserted into the control mice. Intramuscular implanting test: The 16 rabbits were randomly divided into experimental and control groups. Two TiO_2-Ag-nHA/PA66 composite (5 mm × 25 mm) were implanted into left and right erector spinae, respectively. A similar surgery with the exception of implantation was performed on the control rabbits. Intrabony implanting test: The resting 16 rabbits were implanted one TiO_2-Ag-nHA/PA66 composite (3 mm × 5 mm) into left and right lateral epicondyle, respectively. Hemolytic test: A 8-mL anti-coagulation blood was obtained and added with composite powder (0.1,0.15, and 0.2 g).MAIN OUTCOME MEASURES: Biocompatibility and biological security of TiO_2-Ag-nHA/PA66 composite.RESULTS: General toxicity test demonstrated that mice in the two groups had good activity and eating, normal breathing, stable body mass, no paralysis, convulsion, and death. Intramuscular implanting test and intrabony implanting test showed that there was no significant difference in levels of alanine aminotransferase, aspartate transaminase, urea nitrogen, and creatinine and leukocyte numbers between the two groups before implantation and at day 4,1 week, and 2 weeks after implantation (P> 0.05).In particular, there was no significant difference in the experimental group at varying time points (P> 0.05). Intramuscular implanting test indicated that tissue sections in the experimental group displayed coated tissue of materials. The inflammatory variation in the experimental group was generally similar to that in the control group. Intrabony implanting test indicated that tissue sections in the experimental group displayed new bone formation. Hemolytic test suggested that hemolytic ratio of three varying concentrations of TiOrAg-nHA/PA66 composites was less than 5%, which met the normal criterion.CONCLUSION: TiO_2-Ag-nHA/PA66 composite has a good biocompatibility and biological security.

Objective:To investigate the risk factors of acute symptomatic seizures (ASS) and epilepsy in children with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD).Methods:A ambispective cohort study was used including 74 children with MOGAD who were admitted to the Department of Pediatrics of Peking University First Hospital from January 2013 to June 2023 and were followed up. Demographic information, clinical information, treatment status, ASS and epilepsy status were collected. The clinical phenotypes were classified. According to the presence or absence of ASS in the course of disease, the children and the course of disease were divided into groups with and without ASS. Chi-square test, Fisher exact test and Mann Whitney U test were used to analyze the correlation between symptoms and auxiliary examination characteristics and the occurrence of ASS in the two groups of children. Multivariate Logistic regression analysis was used for multivariate analysis. Results:The onset age of the 74 children with MOGAD was 6.58 (3.80, 9.67) years, including 38 females (51.4%) and 36 males (48.6%). The duration of the final follow-up was 2.67 (1.10, 4.12) years, with a total of 239 times acute clinical episodes. ASS occurred in 39.2% (29/74) children during the course of disease and in 29.3% (70/239) of attacks. The common phenotypes were ADEM (67 times (28.0%)), optic neuritis (37 times (15.4%)) and cerebral cortical encephalitis (31 times (13.0%)) in 239 times acute clinical episodes. The incidence of ASS in ADEM and cerebral cortical encephalitis phenotype was 28.4%(19/67) and 100.0% (31/31), respectively. Multivariate analysis showed that cortical involvement on magnetic resonance imaging during clinical attacks was an independent risk factor for ASS ( β=-1.49, OR=0.23) after excluding attacks involving only optic nerve or spinal cord (49 episodes). During the follow-up, 5 children (6.8%) had epilepsy, and all children with epilepsy had multiple clinical attacks of MOGAD and previous ASS. Conclusions:Cortical involvement on magnetic resonance imaging during clinical episodes is an independent risk factor for ASS in children with MOGAD. All MOGAD children with epilepsy had ASS and multiple MOGAD clinical episodes in the past.

Objective:To summarize the clinical characteristics of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and compare the differences in efficacy of different disease-modifying drugs.Methods:An ambispective cohort study was conducted in 42 children diagnosed with MOGAD at Department of Pediatrics, Peking University First Hospital from January 2012 to March 2021 and conducted long-term follow-up to analyze clinical phenotypes and compare the efficacy of different disease-modifying drugs such as rituximab, mycophenolate mofetil and azathioprine. Kruskal-Wallis H test was used to compare the annual relapse rate of disease-modifying drugs at different times, expanded disability status scale (EDSS) score at the last follow-up, and Wilcoxon rank test was used to compare the annual relapse rate before and after modified disease therapy. The Log-rank (Mantel-Cox) survival curve was used to compare the relapse rate of different disease-modifying drugs. Results:Of the 42 cases, 22 were male and 20 were female, with the age at disease onset of 5.96 (2.33-12.90) years. The disease duration was 4.46 (1.25-13.00) years at the last follow-up with 161 clinical acute attacks. Acute disseminated encephalomyelitis (ADEM) was the most common phenotype of first attack and all attacks during disease course ((60% (25/42) for first attack, 38% (61/161) for all attacks). The most common clinical syndrome was neuromyelitis optica spectrum disorders (NMOSD) (50%, 21/42). Of the 42 children, 5 (12%) showed encephalitis and 6 (14%) combined with anti-N-methyl-D-aspartate receptor (NMDAR) antibody overlap syndrome. The most commonly involved areas of brain magnetic resonance imaging (MRI) were subcortical white matter (71%, 88/124), cortex (26%, 32/124) and periventricular white matter (25%, 32/124). Spinal cord MRI was most frequently involved in cervical (70%, 16/23) and thoracic (61%, 14/23) medulla, and 43% (10/23) longitudinally extensive transeverse myelitis. Disease-modifying drugs were used in 34 patients. The annual relapse rate after treatment with rituximab, mycophenolate mofetil and azathioprine decreased (all P<0.05) and there was no statistically significant difference in the annual relapse proportion among the groups ( P=0.307). Conclusions:The most common clinical attack of first and all of MOGAD in children is ADEM, and the most common clinical syndrome is NMOSD. Rituximab, mycophenolate mofetil and azathioprine can reduce the annual relapse rate, but it is not clear effect of which treatment is better.