ABSTRACT
Many sea-level residents suffer from acute mountain sickness (AMS) when first visiting altitudes above 4,000 m. Exercise tolerance also decreases as altitude increases. We observed exercise capacity at sea level and under a simulated hypobaric hypoxia condition (SHHC) to explore whether the response to exercise intensity represented by physiological variables could predict AMS development in young men. Eighty young men from a military academy underwent a standard treadmill exercise test (TET) and biochemical blood test at sea level, SHHC, and 4,000-m altitude, sequentially, between December 2015 and March 2016. Exercise-related variables and 12-lead electrocardiogram parameters were obtained. Exercise intensity and AMS development were investigated. After exposure to high altitude, the count of white blood cells, alkaline phosphatase and serum albumin were increased (P < 0.05). There were no significant differences in exercise time and metabolic equivalents (METs) between SHHC and high-altitude exposures (7.05 ± 1.02 vs. 7.22 ± 0.96 min, P = 0.235; 9.62 ± 1.11 vs. 9.38 ± 1.12, P = 0.126, respectively). However, these variables were relatively higher at sea level (8.03 ± 0.24 min, P < 0.01; 10.05 ± 0.31, P < 0.01, respectively). Thus, subjects displayed an equivalent exercise tolerance upon acute exposure to high altitude and to SHHC. The trends of cardiovascular hemodynamics during exercise under the three different conditions were similar. However, both systolic blood pressure and the rate-pressure product at every TET stage were higher at high altitude and under the SHHC than at sea level. After acute exposure to high altitude, 19 (23.8%) subjects developed AMS. Multivariate logistic regression analysis showed that METs under the SHHC {odds ratio (OR) 0.355 per unit increment [95% confidence intervals (CI) 0.159-0.793], P = 0.011}, diastolic blood pressure (DBP) at rest under SHHC [OR 0.893 per mmHg (95%CI 0.805-0.991), P = 0.030], and recovery DBP 3 min after exercise at sea level [OR 1.179 per mmHg (95%CI 1.043-1.333), P = 0.008] were independently associated with AMS. The predictive model had an area under the receiver operating characteristic curve of 0.886 (95%CI 0.803-0.969, P < 0.001). Thus, young men have similar exercise tolerance in acute exposure to high altitude and to SHHC. Moreover, AMS can be predicted with superior accuracy using characteristics easily obtainable with TET.
ABSTRACT
Twenty batches of Aurantii Fructus Immaturus(AFI) were collected, with their peel and pulp taken as research objects. Ultra-high performance liquid chromatography(UPLC) fingerprints of peel and pulp of AFI were established with 17 common peaks in peel and 10 in pulp. Six kinds of flavonoids were identified, i.e., narirutin, naringin, rhoifolin, hesperidin, neohesperidin and nobiletin. The Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine was employed for similarity analysis, which showed that the chromatographic peaks of peel and pulp were basically similar to their respective reference fingerprints, with all similarities greater than 0.90. The similarity between peel and pulp of the same batch of AFI ranged from 0.850 to 0.983. Cluster analysis(CA), principal component analysis(PCA), and orthogonal partial least squares discriminant analysis(OPLS-DA) were conducted on the common peaks of peel and pulp of AFI with SPSS 17.0 and SIMCA 14.1. Combined with the reference fingerprints, these analyses revealed 12 differential components regarding peel and pulp. Further, the content of the 6 flavonoids and synephrine was determined. The proposed method integrating UPLC fingerprint and multicomponent quantitative analysis is applicable to the quality evaluation of AFI. The results provide a certain basis for the scientific connotation about the appearance characteristic of AFI.
