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Plasma selenium and the risk of first stroke in adults with hypertension: a secondary analysis of the China Stroke Primary Prevention Trial.
Wang, Z, Ma, H, Song, Y, Lin, T, Liu, L, Zhou, Z, Wei, Y, Huang, X, Chen, P, Liu, C, et al
The American journal of clinical nutrition. 2022;(1):222-231
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Abstract
BACKGROUND Previous studies have indicated that selenium (Se) may play an important role in cardio-cerebrovascular disease. However, the relation between circulating selenium and risk of first stroke remains inconclusive. OBJECTIVES We conducted a secondary analysis of the China Stroke Primary Prevention Trial (CSPPT), using a nested case-control design, and aimed to investigate the correlation between Se concentration and first stroke risk in adults with hypertension and examine the potential effect modifiers. METHODS In the CSPPT, a total of 20,702 adults with hypertension were randomly assigned to a double-blind daily treatment with either 10 mg enalapril and 0.8 mg folic acid or 10 mg enalapril alone. A total of 618 first stroke cases and 618 controls matched for age, sex, treatment group, and study site were included in this study. RESULTS During a median follow-up duration of 4.5 y (IQR: 4.2-4.6 y), there was a significant inverse association between plasma Se and the risk of first stroke (per SD increment; adjusted OR: 0.81; 95% CI: 0.68, 0.96) and ischemic stroke (per SD increment; adjusted OR: 0.76; 95% CI: 0.62, 0.93). Furthermore, a stronger inverse association between plasma Se and first stroke was observed in participants with higher folate concentrations at baseline [≥7.7 ng/mL (median), adjusted OR: 0.67; 95% CI: 0.54, 0.85, compared with <7.7 ng/mL, adjusted OR: 0.98; 95% CI: 0.80, 1.21; P-interaction = 0.008] and those with higher time-averaged systolic blood pressure (SBP) over the treatment period (≥140 mm Hg, adjusted OR: 0.71; 95% CI: 0.58, 0.86, compared with <140 mm Hg, adjusted OR: 0.96; 95% CI: 0.77, 1.20; P-interaction = 0.023). CONCLUSIONS There was a significant inverse association between plasma Se and risk of first stroke in Chinese adults with hypertension, especially among those with higher baseline folate concentrations and those with higher time-averaged SBP over the treatment period. This trial was registered at clinicaltrials.gov as NCT00794885.
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Synthesis and evaluation of a novel water-soluble high Se-enriched Astragalus polysaccharide nanoparticles.
Meng, Y, Zhang, Y, Jia, N, Qiao, H, Zhu, M, Meng, Q, Lu, Q, Zu, Y
International journal of biological macromolecules. 2018;(Pt B):1438-1448
Abstract
Selenium is an essential trace element in human body. Se-deficiency is common phenomenon in all over the world, which severely harms the health of organism and causes the etiology of many chronic, degenerative diseases, such as atherosclerosis, arthritis, cancers, hypoimmunity, hypothyroidism and viral diseases. So, the research on preparation of Se-supplementing with the effective, safe and high Se content was imperative. In this study, Se-enriched Astragalus polysaccharide nanoparticles (Se-APS) were prepared by the previous optimization experimental conditions, as follows: reaction temperature 80.5 °C, pH 7.8, ratio of catalyst to APS 0.57:1.0 g·g-1, and reaction time 62 min. The Se content of Se-APS was as high as 13.42 ± 0.37%, characterized by energy spectrometer, thermogravimetry, X-ray diffraction, fourier transform infrared, particle size, zeta potential and atomic force. Se release of the Se-APS in vitro followed the Higuchi's kinetics model and exhibited the basically same release pattern in artificial gastric juice (pH 2.0), artificial intestinal juice (pH 8.0) and PBS (pH 7.4). The proliferation of T-lymphocytes with Se-APS incubation increased at an average of 13.87%, comparing with APS. It could not only enhance the proliferation of T-lymphocytes, but also effectively suppress malignant proliferation of HepG2 cells and reduce cell migration and invasion. We prepared a novel water-soluble Se-APS by using a chelating method, which was promising as a novel Se supplements with high Se content and good bioactivity.
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(77)Se chemical shift tensor of L-selenocystine: experimental NMR measurements and quantum chemical investigations of structural effects.
Struppe, J, Zhang, Y, Rozovsky, S
The journal of physical chemistry. B. 2015;(9):3643-50
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Abstract
The genetically encoded amino acid selenocysteine and its dimeric form, selenocystine, are both utilized by nature. They are found in active sites of selenoproteins, enzymes that facilitate a diverse range of reactions, including the detoxification of reactive oxygen species and regulation of redox pathways. Due to selenocysteine and selenocystine's specialized biological roles, it is of interest to examine their (77)Se NMR properties and how those can in turn be employed to study biological systems. We report the solid-state (77)Se NMR measurements of the L-selenocystine chemical shift tensor, which provides the first experimental chemical shift tensor information on selenocysteine-containing systems. Quantum chemical calculations of L-selenocystine models were performed to help understand various structural effects on (77)Se L-selenocystine's chemical shift tensor. The effects of protonation state, protein environment, and substituent of selenium-bonded carbon on the isotropic chemical shift were found to be in a range of ca. 10-20 ppm. However, the conformational effect was found to be much larger, spanning ca. 600 ppm for the C-Se-Se-C dihedral angle range of -180° to +180°. Our calculations show that around the minimum energy structure with a C-Se-Se-C dihedral angle of ca. -90°, the energy costs to alter the dihedral angle in the range from -120° to -60° are within only 2.5 kcal/mol. This makes it possible to realize these conformations in a protein or crystal environment. (77)Se NMR was found to be a sensitive probe to such changes and has an isotropic chemical shift range of 272 ± 30 ppm for this energetically favorable conformation range. The energy-minimized structures exhibited calculated isotropic shifts that lay within 3-9% of those reported in previous solution NMR studies. The experimental solid-state NMR isotropic chemical shift is near the lower bound of this calculated range for these readily accessible conformations. These results suggest that the dihedral information may be deduced for a protein with appropriate structural models. These first-time experimental and theoretical results will facilitate future NMR studies of selenium-containing compounds and proteins.