Objective:To investigate the topological properties of whole-brain functional networks in first-episode drug-na?ve adolescents with major depressive disorder (MDD).Methods:Seventy-six first-episode drug-na?ve adolescents with MDD admitted to Department of Neurology, Xiangyang No.1 Hospital Affilated to Hubei University of Medicince from January 2022 to January 2023 were selected as study subjects; 66 gender- and age-matched healthy controls (HCs) were recruited via advertisement. All subjects underwent resting-state functional MRI. The whole-brain functional networks were constructed for each subject; and then, the global topological metrics (global efficiency, local efficiency, clustering coefficient, characteristic path length, normalized clustering coefficient, normalized characteristic path length, and small-worldness properties) and local topological metrics (nodal degree centrality, nodal efficiency and nodal betweenness centrality) of the functional brain networks were analyzed between the two groups using graph-theory methods. Network-based statistics were used to examine between-group differences in functional connectivity strength of whole brain networks. Results:Small-worldness properties were demonstrated in both MDD group and HC group. MDD patients showed significantly higher global efficiency (0.129[0.124, 0.132] vs. 0.131[0.128, 0.133]), significantly lower clustering coefficient and characteristic path length (0.143[0.139, 0.146] vs. 0.139[0.135, 0.144]; 0.457[0.446, 0.734] vs. 0.451[0.440, 0.463]), and significantly increased nodal centralities in the right inferior parietal lobule, bilateral caudate nucleus and bilateral thalamus of brain functional networks compared with HCs ( P<0.05, FDR-corrected). Compared with HCs, MDD patients exhibited obviously lower functional connectivity strength in the orbitofrontal-temporal and anterior cingulate-limbic-temporal circuits. Conclusion:Abnormal alterations of topological properties of the brain functional networks are found in adolescents with MDD, which may be the underlying neuropathologic basis for MDD.

BACKGROUND: China has the world's largest tea plantation area in the world. To sustain high yields of the tea, multiple pesticides are used on tea crops to control pests. Organophosphorus (OP) pesticides are among the most widely used types of agricultural pesticides in China. As tea is a significant potential source of exposure to pesticide residues, the public concern has increased in relation to pesticide residues found in tea in China. The aim of the study was to estimate cumulative dietary exposure to OP residues from tea infusion for Chinese tea consumers to determine whether exposure to OP residues from tea infusion is a cause of health concern for tea consumers in China. METHODS: OP residue data were obtained from the China National Monitoring Program on Food Safety (2013-2014), encompassing 1687 tea samples from 12 provinces. Tea consumption data were obtained from the China National Nutrient and Health Survey (2002), comprising 506 tea consumers aged 15-82 years. The transfer rates of residues from tea leaves into tea infusions were obtained from the literature. The relative potency factor (RPF) approach was used to estimate acute cumulative exposure to 20 OP residues from tea infusion using methamidophos as the index compound. Dietary exposure was calculated in a probabilistic way. RESULTS: For tea consumers, the mean and the 99.9th percentile (P99.9) of cumulative dietary exposure to OP residues from tea infusion equalled 0.08 and 1.08 μg/kg bw/d. When compared with the acute reference dose (ARfD), 10 μg/kg bw/d for methamidophos, this accounts for 0.8 and 10.8% of the ARfD. CONCLUSIONS Even when considering OP residues from vegetables, fruits and other foods, there are no health concerns based on acute dietary exposure to OP residues from tea infusion. However, it is necessary to strengthen the management of the OP pesticides used on tea in China to reduce the risk of chronic dietary exposure to OPs from tea infusion.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; China ; Dietary Exposure ; analysis ; Female ; Humans ; Male ; Middle Aged ; Organophosphorus Compounds ; analysis ; Pesticide Residues ; analysis ; Risk Assessment ; methods ; Tea ; chemistry ; Young Adult