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61.
El Barkil M Gagnieu MC Guitton J 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2007,854(1-2):192-197
A sensitive high-performance liquid chromatography method coupled to UV and single mass spectrometry (MS) detection was developed for the determination of tenofovir in human plasma. A solid phase extraction procedure (Bond-Elut C18 Varian cartridges) provided high extraction efficiency (91% for tenofovir and 68.8% for the internal standard, 3-methylcytidine). An atlantis-dC-18 analytical column is used with an isocratic mode elution of a mixture (pH 2.5) of ammonium acetate/methanol (98.5:1.5, v/v). Detection was performed at 260 nm and by using the ion at m/z 288. The signals from both detectors were validated over the range of 10-1000 ng mL(-1) and were found to be linear, accurate and precise. At the lowest limit of quantification, 10 ng mL(-1) for UV and 5 ng mL(-1) for MS, the average coefficient of variation was 6.9 and 3.9%, respectively. To investigate the potential of the validated method for clinical studies, more than 170 samples from HIV-infected adult patients were then analyzed with this assay. A good correlation was observed between the results obtained with both detectors. However, in several cases discordant results were observed between UV and MS detections. Therefore, tenofovir can sometimes suffer from interferences using either UV or single MS detection. We concluded that the double detection allows to obtain a more specific quantification of tenofovir. The present assay is sound and can be used for therapeutic drug monitoring allowing a higher reliability of the results which are transmitted to the medical team. 相似文献
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RPMI 1640 culture medium was chosen to simulate body fluids, and after exposure to 0.085 approximately 0.092 T static magnetic fields (SMF), surface tension, pH, dissolved oxygen, and UV-visible spectrum were measured. Compared with the control group in the normal geomagnetic field, the pH value increased about 0.14 units, dissolved oxygen increased about 14%, and the UV-visible spectra were different in peak intensity but without a shift in the peak. Surface tension showed no significant difference in the two groups. This data suggests that SMF can change some of the physical and chemical properties of RPM1 1640 solution, and may contribute to understanding biological effects of SMF. 相似文献
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Hai-Ming Xu Feng-Hua Sui Mei-Hua Sun Gong-Liang Guo 《Journal of cellular physiology》2019,234(3):2537-2551
Recent studies have shown that circulating microRNAs (miRNA) play a critical role in diagnosing acute coronary syndrome (ACS). This study aims to investigate the effect of miR-224 on atherosclerotic plaques forming and vascular remodeling in ACS and its relationship with TGF-β/Smad pathway. Myocardial infarction (MI) rat model was established and lentivirus vector of miR-224 inhibitor was prepared for investigating the effect of downregulated miR-224 on the contents of nitric oxide (NO) and endothelin-1 (ET-1), blood lipid levels and inflammatory factor levels in serum as well as the TGF-β/Smad pathway. The rats suffering from MI had decreased survival rates and exhibited reduced levels of NO, high-density lipoprotein cholesterol, and lumen diameter, and Smad7 messenger RNA (mRNA) and protein expression; while had significantly increased ratio of heart weight or body weight, levels of ET-1, inflammatory factors, blood lipid indexes, vascular remodeling indexes, collagen volume fraction, vulnerable atherosclerotic plaque area, VCAM-1 and MMP-2 protein expression, TGF-β, Smad2, Smad3, and Smad4 mRNA and protein expression. After inhibiting the TGF-β/Smad pathway, the rats suffering from MI showed notably opposite trend. In conclusion, downregulation of miR-224 expression promotes the formation of vulnerable atherosclerotic plaques and vascular remodeling in ACS through activation of the TGF-β/Smad pathway. Therefore, this study provides a new therapeutic target for ACS. 相似文献
65.
Jie Zhou Jiajia Zhang Alexander C. Mclain Wenbin Lu Xuemei Sui James W. Hardin 《Biometrics》2019,75(3):853-863
Varying‐coefficient models have become a common tool to determine whether and how the association between an exposure and an outcome changes over a continuous measure. These models are complicated when the exposure itself is time‐varying and subjected to measurement error. For example, it is well known that longitudinal physical fitness has an impact on cardiovascular disease (CVD) mortality. It is not known, however, how the effect of longitudinal physical fitness on CVD mortality varies with age. In this paper, we propose a varying‐coefficient generalized odds rate model that allows flexible estimation of age‐modified effects of longitudinal physical fitness on CVD mortality. In our model, the longitudinal physical fitness is measured with error and modeled using a mixed‐effects model, and its associated age‐varying coefficient function is represented by cubic B‐splines. An expectation‐maximization algorithm is developed to estimate the parameters in the joint models of longitudinal physical fitness and CVD mortality. A modified pseudoadaptive Gaussian‐Hermite quadrature method is adopted to compute the integrals with respect to random effects involved in the E‐step. The performance of the proposed method is evaluated through extensive simulation studies and is further illustrated with an application to cohort data from the Aerobic Center Longitudinal Study. 相似文献
66.
Ma Si Li Yaxin Li Xin Sui Xiaolei Zhang Zhenxian 《Journal of Plant Growth Regulation》2019,38(2):494-500
Journal of Plant Growth Regulation - Carbohydrate produced by photosynthesis is loaded into phloem via collection phloem, translocated via the transport phloem, and unloaded by release phloem into... 相似文献
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Cailian Fan Sui Liang Mengnan Ye Wanjun Cai Miao Chen Yunlong Hou Jun Guo Yi Dai 《Journal of cellular and molecular medicine》2022,26(9):2607
Pathological cardiac hypertrophy is the most important risk factor for developing chronic heart failure. Therefore, the discovery of novel agents for treating pathological cardiac hypertrophy remains urgent. In the present study, we examined the therapeutic effect and mechanism of periplocymarin (PM)‐mediated protection against pathological cardiac hypertrophy using angiotensinII (AngII)‐stimulated cardiac hypertrophy in H9c2 cells and transverse aortic constriction (TAC)‐induced cardiac hypertrophy in mice. In vitro, PM treatment significantly reduced the surface area of H9c2 cells and expressions of hypertrophy‐related proteins. Meanwhile, PM markedly down‐regulated AngII‐induced translocation of p‐STAT3 into the nuclei and enhanced the phosphorylation levels of JAK2 and STAT3 proteins. The STAT3 specific inhibitor S3I‐201 or siRNA‐mediated depleted expression could alleviate AngII‐induced cardiac hypertrophy in H9c2 cells following PM treatment; however, PM failed to reduce the expressions of hypertrophy‐related proteins and phosphorylated STAT3 in STAT3‐overexpressing cells, indicating that PM protected against AngII‐induced cardiac hypertrophy by modulating STAT3 signalling. In vivo, PM reversed TAC‐induced cardiac hypertrophy, as determined by down‐regulating ratios of heart weight to body weight (HW/BW), heart weight to tibial length (HW/TL) and expressions of hypertrophy‐related proteins accompanied by the inhibition of the JAK2/STAT3 pathway. These results revealed that PM could effectively protect the cardiac structure and function in experimental models of pathological cardiac hypertrophy by inhibiting the JAK2/STAT3 signalling pathway. PM is expected to be a potential lead compound of the novel agents for treating pathological cardiac hypertrophy. 相似文献
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