Objective To investigate the risk factors which affect complex febrile seizures developing into epilepsy. Methods Retrospective analysis of 162 complex febrile seizure cases was carried out. Results Fifteen out of 35 children who had familial history of epilepsy developed into epilepsy. Twenty out of 55 cases who had neurological abnormalities developed into epilepsy. Nineteen out of 37 cases of who the length between fever and febrile seizure was less than 1 h developed into epilepsy, but only 13 in 125 patients developed into epilepsy when the interval between fever and seizure was more than 1 h. Conclusion The predictive risk factors for complex febrile seizures developing into epilepsies are familial history of epilepsy, abnormal neurological development, and short intervals between fever and febrile seizure activities.

Pyran- and furanocoumarins are key representatives of tetrahydropyrans and tetrahydrofurans, respectively, exhibiting diverse physiological and medical bioactivities. However, the biosynthetic mechanisms for their core structures remain poorly understood. Here we combined multiomics analyses of biosynthetic enzymes in Peucedanum praeruptorum and in vitro functional verification and identified two types of key enzymes critical for pyran and furan ring biosynthesis in plants. These included three distinct P. praeruptorum prenyltransferases (PpPT1-3) responsible for the prenylation of the simple coumarin skeleton 7 into linear or angular precursors, and two novel CYP450 cyclases (PpDC and PpOC) crucial for the cyclization of the linear/angular precursors into either tetrahydropyran or tetrahydrofuran scaffolds. Biochemical analyses of cyclases indicated that acid/base-assisted epoxide ring opening contributed to the enzyme-catalyzed tetrahydropyran and tetrahydrofuran ring refactoring. The possible acid/base-assisted catalytic mechanisms of the identified cyclases were theoretically investigated and assessed using site-specific mutagenesis. We identified two possible acidic amino acids Glu303 in PpDC and Asp301 in PpOC as vital in the catalytic process. This study provides new enzymatic tools in the epoxide formation/epoxide-opening mediated cascade reaction and exemplifies how plants become chemically diverse in terms of enzyme function and catalytic process.