Pharmacokinetics study of astragaloside Ⅳ by intravenous administration with intermittent blood sampling in intact rats / 中国临床药理学与治疗学

AIM: To establish a sensitive method for quantitative determination of astragaloside Ⅳ (AGS-Ⅳ) in plasma and a preliminary evaluation of its pharmacokinetics parameters in intact rats. METHODS: A liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) was applied for determining AGS-Ⅳ in plasma by using digoxin as the internal standard (I.S.). Six rats were given AGS-Ⅳ 2.0 mg/kg by intravenous infusion for 5 min. Blood samples were drawn intermittently with each intact rat from left femoral artery at 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2, 4, 6, 10, 14 and 24 h after medication. The samples were prepared by solid phase extraction and analyzed through a triple quadrupole mass spectrometer equipped with an electrospary probe. The samples were monitored in selected ion recording (SIR) mode of positive ions by using target ions at m/z 807.5 for AS- Ⅳand at m/z 803.5 for I.S. RESULTS: Calibration curves were linear over the ranges 1-1 000 ng/mL for AGS-Ⅳ (r=0.9992). The intra-and inter-day assay variability values were less than 6% and 8%, respectively. Extraction recoveries from plasma were 92.8%-98.4% for AGS-Ⅳ and 80.0%-90.9% for digoxin, respectively. The lower limit of quantitation (LLOQ) for AGS-Ⅳ was 0.5 ng/mL. The concentration-time curves of AGS-Ⅳ for each rat were fitted to an open two-compartment model by CAPP program. The pharmacokinetics parameters of AGS-Ⅳ were as following: the elimination half-life (t1/2β), clearance rate (CL), distribution volume at steady state (Vss), and AUC0-∞ were (3.46±0.52) h, (0.47±0.02) L/h, (0.76±0.16) L/kg and (4.27±0.19) μg·mL-1·h, respectively. CONCLUSION: These results show that this method is satisfied for the measurements of pharmacokinetics study for AGS-Ⅳ.

The expression of insulin-like growth factor-I mRNA and polypeptide in rat osteoblasts with exposure to parathyroid hormone / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the insulin-like growth factor-I (IGF-I) gene and polypeptide expression in cultured rat osteoblast (ROB) and the role of IGF-I in mediating the cell-to-cell communication by mimicking the pharmacokinetics of parathyroid hormone (PTH).</p><p><b>METHODS</b>The ROB was cultured with three kinds of treatment: (1) Control (Ctr), the cells were cultured without PTH during the first 6 hours and the subsequent 42 hours in a 48-hour cycle; (2) Intermittent exposure to PTH (Itm), the cells were cultured with PTH during the first 6 hours, but without PTH in the subsequent 42 hours; and (3) Continuous exposure to PTH (Ctu), the cells were cultured with PTH during the first 6 hours and the subsequent 42 hours.</p><p><b>RESULTS</b>The bone-forming activities of ROB were increased in Itm and inhibited in Ctu. The IGF-I mRNA content in Itm cells was elevated only during the first 6 hours and that in Ctu cells was elevated at any time during an incubation cycle. The free IGF-I concentration in the medium of Itm cells was generally higher and that of the Ctu cells was generally lower compared with those of the Ctr cells. The IGF-I antibody significantly reduced the alkaline phosphatase activity within the cells of Ctr and Itm.</p><p><b>CONCLUSIONS</b>PTH rapidly and constantly stimulates the IGF-I gene transcription of osteoblast. There was an obvious discrepancy between the IGF-I mRNA content within the osteoblast and the free IGF-I level around the osteoblast in either mode of PTH action. The IGF-I might be important for osteoblast-osteoblast communication and bone-forming activity, not only in intermittent PTH administration, but also in the physiological functioning of osteoblasts.</p>

Variation of Formaldehyde Concentrations in Indoor Air of Newly Decorated Office / 环境与健康杂志

Objective To study the variation of formaldehyde concentrations in indoor air of newly decorated office room Methods 7 office rooms decorated 3 months ago were selected to be monitored every 1 5 months for 5 times, and the room temperature was measured at the same time Results During the period from the 3rd month to the 10th month after the decoration,the room temperature dropped from 14 ℃ to 10 ℃,and went up to 26 ℃ again;the average formaldehyde concentration decreased from 0 22 mg/m 3 to 0 09 mg/m 3 and then increased to 0 22 mg/m 3; the over standard rate decreased from 57 1% to 0% and then increased to 85 7% Conclusion During the course of monitoring,formaldehyde concentrations in indoor air did not decrease apparently with the prolongation of the duration after the end of the decoration,but varied according the changes in room temperature,and formaldehyde concentrations in some rooms were higher than the national hygienic standard significantly