Objective:To explore the characteristics and influencing factors of blood carnitine metabolism in premature infants.Methods:A retrospective analysis of 37 037 neonates with negative results of genetic metabolic disease screening at Guangxi Newborn Disease Screening Center from 2018 to 2021, of which 34 517 normal full-term infants were the control group and 2 520 preterm infants were the research group.According to gestational age, the preterm infants were further divided into three groups: extremely preterm group( n=232), moderately preterm group( n=324)and late preterm group( n=1 964). According to birth weight, they were divided into three groups: very low birth weight group( n=188), low birth weight group( n=1 276)and normal birth weight group( n=1 056). According to blood collection time, they were divided into three groups: 3~7 days group( n=1 990), 8~14 days group( n=342) and 15~28 days group( n=188). Tandem mass spectrometry was used to detect the levels of 31 carnitines in dried blood spots and analyze the differences in the levels of metabolic indicators in each group. Results:Carnitine levels in preterm infants are most affected by gestational age.Adjusting the physiological and pathological conditions of premature infants and other related factors, grouped by gestational age, there were differences in the levels of 31 carnitines among the groups(all P<0.05), the smaller the gestational age, the greater the difference in carnitine levels; grouped by blood collection time, there were statistically significant differences in carnitine levels between preterm infants with different blood collection age groups and full-term 3~7 days groups(all P<0.05), and showing age-related; there are differences among 31 carnitines grouped by body weight(all P<0.05), the smaller the body weight, the greater the difference in carnitine levels.Combined with the analysis of gestational age, birth weight and blood collection date, 17 indicators including C0, C2, C3, C4, C6DC, C10, C10∶1, C12, C12∶1, C14, C14∶1, C14OH, C16, C16∶1, C18, C18∶1 and C18∶1OH are important biomarkers of carnitine metabolism in premature infants. Conclusion:Carnitine in premature newborns has different metabolic differences at different gestational ages, birth weights and blood collection ages, which provides a strong basis for establishing reference standards and interpretation of preterm infants in the laboratory in this region, and provides reasonable and effective early diagnosis and treatment for clinical practice.Meanwhile, it provides an optimized program for timely detection of carnitine deficiency and carnitine supplementation to improve nutrition of premature infants.

OBJECTIVE To compare the chemical components contained in Artemisiae Scopariae Herba （ASH） standard decoction and its decoction pieces， and provide foundation of their pharmacological substances. METHODS ASH standard decoction and its decoction pieces were prepared； UFLC-Q-TOF-MS/MS method was used for the detection in the negative ion mode， and the total ion chromatogram was extracted by the PeakView 1.6 software. By comparing with reference substances， literature data， and online search of compound database such as PubChem， the chemical components contained in ASH standard decoction and its decoction pieces were identified and analyzed for the differences. RESULTS A total of 125 chemical components were identified in ASH standard decoction and its decoction pieces， including 50 organic acids， 39 flavonoids， 3 coumarins， 2 amino acids， 5 lignans， and 26 others. 3-methoxy-caffeic acid-4-O- β -D-glucoside， p-hydroxybenzoic acid， caffeic acid 4-O- glucoside， spiraeoside， and phenyl β-D-glucoside in ASH standard decoction were not detected in its decoction pieces， while 6′-6′ chlorogenic acid dimer， quercetin-5-glucoside， apigenin 7-methyl ether 5-（6″-malonylglucoside）， quercetin-3-O-arabinoside， 6″-caffeoylhyperin and 6-O-caffeoyl-D-glucoside in decoction pieces were not detected in the standard decoction. CONCLUSIONS Most components in ASH decoction pieces are transferred to its standard decoction， but a few components undergo chemical reactions in whole or in part during the boiling process， transforming into other or new components in the standard decoction.