Papers by Keyword: Dose-Response

Abstract: Study traditional Chinese medicine prescription compatibility chemical components Dose-response relationship based on multiplicative signal correction and partial least squares (MSC-PLS). Method: mathematical modeling base on MSC-PLS. Results: study the compatibility chemical components of the dachengqi decoction; mining the regression coefficient and equation, VIP sorting, loadings Bi plot base on the method. Conclusion: the method mining the data information and optimization the compatibility of the dachengqi decoction cure ileus rats is feasible and effective.

Abstract: Polycyclic aromatic hydrocarbons (PAH) are known to be pollutants in soil, however there are no effective methods available for determining their ecotoxic effects. We investigated Cytochrome P450 (P450) in earthworms (Eisenia fetida) as a potential biomarker of PAH pollutants in soil. Three types of PAHs were tested which included phenanthrene (Phe), fluoranthene (Fla) and pyrene (Py). Earthworm gut was selected to measure the total P450 content in cellular microsomes. Dose-response relationships between total P450 content in earthworm gut and PAH concentration (60, 120, 240, 480 and 960μg kg^-1 soil (dry weight)) were determined for different exposure durations (1, 3, 7 and 14 days). Results showed that the content of P450 in earthworm changed with exposure to each of PAHs. Biphasic effects were identified in response to each of PAHs tested, in which total P450 content increased due to short, low concentration doses, and decreased due to longer, high concentration doses. Alterations to total P450 content in the presence of PAHs, show that it is a promising biomarker for identifying ecotoxic pollutants at sublethal dose ranges in soil. Further research to identify the specific activity of P450 isoenzymes could further develop and also complement this tool.

Abstract: The aim of this study is to investigate in vivo local BMP-2 PK and bone induction in two bioceramics blocks (HAp, β-TCP), based on different composition and surface structures. We estimated the in vivo release profile of 125I–labeled BMP-2 and bone induction of hard tissues histologically. β-TCP is more effective for both BMP-2 retention and bone induction, compared to HAp, in the ectopic model.

Abstract: The purpose of this study was to evaluate the effects of collagen membrane coated with PLGA on bone regeneration in rat calvarial defect. Five groups of 10 animals each received either collagen membrane coated with 0.5%, 1%, 3% concentration of PLGA, collagen membrane only or surgical control. Each group of animals was healed into 2 healing periods of 2(5 animals) and 8(5 animals)weeks and histologic and histomorphometric analysis were done. The results of the following study revealed that surgical implantation of collagen membranes coated with PLGA enhanced local bone formation at both 2 and 8 weeks independent of different PLGA concentrations. In conclusion, collagen membrane coated with PLGA shows a significant bone formation behavior irrespective of their concentration.

Abstract: Hydroxyapatite (HAp) has been used as a biomaterial for hard tissues. Critical characteristics of biomaterials will include surface geometry, hydrophobicity and hydrophilicity, crystallinity, biodegradation rates, and release pharmacokinetics (PK) of incorporated molecules such as BMP-2. Optimizing BMP-2 for clinical application may be dependent on localized sustained release from biomaterials. We forcused on in vivo local BMP-2 PK and bone induction in two ceramics systems, based on different surface structures. The functionally graded apatites (fg-HAp) was designed by the step-wise calcinations and partial dissolution-precipitation methods. We estimated the in vivo release profile of 125I-labeled BMP-2 from fg-HAp and the dose response of bone induction by BMP-2 in the back subcutis histologically. Bulk-HAp (b-HAp) by only the step-wise calcinations was prepared as a control. The amount of BMP-2 remaining in the fg-HAp at 1 day after implantation was 83.8%, while that was 34.6% in the b-HAp. Moreover, ectopic bone formation were found surely in the fg-HAp/BMP-2 (0.5μg) system at 3 weeks, not in the b-HAp/BMP-2 system. By using fg-HAp, it is likely that an extremely low dose of BMP-2 is enough to enhance bone induction if BMP-2 is appropriately delivered to the site of action.