Objective To investigate the changes in plasma very long chain fatty acids (VLCFAs),and to explore its relationship with obesity-related index in obese children.Methods One hundred and sixty-six obese children aged 7 to 12 years old were investigated and 148 health children matched with age and sex were selected as control group.Their height,weight,and waist circumference (WC) were measured.The percentage of body fat (PBF) was tested by dual-energy X-ray absorptiometry.Fasting blood triglycerides (TG),total cholesterol (TC),high density lipoprotein-cholesterol (HDL-C),low density lipoprotein-cholesterol (LDL-C) levels,fasting plasma glucose,and fasting insulin (FINS) were determined.The body mass index (BMI),BMI-Z score,waist to height ratio (WHtR),and homeostasis model assessment for insulin resistance (HOMA-IR) were calculated.The plasma VLCFAs were analyzed by gas chromatography-mass spectrometry.Results (1) Compared with normal control children,body weight,BMI,BMI-Z score,WC,WHtR,PBF,TG,TC,LDL-C,FINS,and HOMA-IR in obese children were increased (all P ＜ 0.05),and the level of HDL-C was decreased (P ＜ 0.05).(2) The plasma levels of docosamonoenoic acid (C22 ∶ 1 n-9) and arachidonic acid (C20 ∶ 4n-6) were decreased while the levels of arachicacid (C20 ∶ 0) and eicosapentaenoic acid (C20 ∶ 5n-3) increased in obese children compared to non-obese children.(3) The linear correlation analysis showed that PBF was positively correlated with C20 ∶ 0 and C20 ∶ 5n-3,and negatively correlated with C20 ∶ 4n-6.WHtR was negatively correlated with C22 ∶ 1 n-9 and positively correlated with C20 ∶ 0 (4) The multiple stepwise regression analysis showed that C20 ∶ 0 was the main factor for PBF,and C22 ∶ 1 n-9 and C20 ∶ 0 were the main factors for WHtR.Conclusion The metabolic abnormality of plasma very long chain fatty acids exists in obese children.The changes in C20 ∶ 0,C22 ∶ 1 n-9,and C20 ∶ 5n-3 may be associated with obesity in children.

Didangtang is a classic formula for treating blood stasis and heat， as recorded in the Treatise on Febrile Diseases， and it has been highly praised by medical practitioners throughout history. It has been recorded in many traditional Chinese medical texts and used to this day. This article comprehensively examined the records of Didangtang in different ancient versions of Treatise on Febrile Diseases by excavating and sorting out related ancient medical books and modern literature. It also investigated the dosage unit measurement， preparation method， and content of the formula in medical books throughout history. The article provided a detailed summary and exploration of the origins and processing methods of rhubarb， peach kernels， leeches， and flies in the formula. At the same time， it reviewed the clinical practice of Didangtang by medical practitioners throughout history in relevant medical books， mainly including the adjustment of dosage forms， the increase or decrease in medicinal taste and dosage， the expansion of clinical application， and the creation and elucidation of similar formulas. Although there may be differences in the above information among medical practitioners throughout history， the basic idea of attacking blood stasis and heat is consistent. In addition， based on clinical practice， the author adhered to the principle of treating stasis and heat disease as the first reference when using Didangtang. It was suggested that blood should be circulated instead of stopping in the treatment of stasis and heat accumulation syndrome. At the same time， it was believed that the use of the method of attacking stasis and heat to regulate brain diseases and mental illnesses derives from the fact that removing stasis and generating new energy can nourish the heart and mind， providing ideas for the treatment of such diseases with Didangtang. On this basis， modern clinical and animal experiments have shown that Didangtang has certain effects in improving microcirculation disorders， regulating blood rheology and hemodynamics， enhancing insulin resistance， and inhibiting inflammatory reactions. This may be an important mechanism for the formula to ''conquer blood stasis and heat''. This article explored the textual research and clinical mechanism of Didangtang， presenting facts and evidence， so as to provide a reference for the clinical application of Didangtang and the research on other prescriptions.