Articles

Methamphetamine and its metabolite amphetamine are frequently abused drugs. Whether obtained legally or from clandestine laboratories it is of relevance to determine the chiral makeup of these drugs for investigative purpose. Although urine and oral fluid matrices are commonly offered, less available to independent laboratories are techniques to verify dextro (D-) or levo (L-) (meth)amphetamine from human K2EDTA plasma. This paper outlines the development and validation of a method that includes the addition of internal standard and a two-step liquid-liquid extraction to remove the analytes from human K2EDTA plasma by triple quadrupole mass spectrometry (LC-MS/MS). The assay was validated according to the United States Food and Drug Administration and College of American Pathologists guidelines, including assessment of the following parameters in plasma validation samples: linear range, limit of detection, lower limit of quantitation, matrix effects, inter- and intra-day assay precision and accuracy, carry over, linearity of dilution, matrix effects and stability. The outcome is a validated and reliable method for the determination of D- and L- isomer concentration of meth(amphetamine) human plasma samples that can be easily adopted by independent clinical laboratories.

<b>Objective</b>: The study investigated the biological effects and molecular mechanisms of platelet-rich plasma (PRP) on periodontal bone regeneration. <b>Methods:</b> Electronic and manual searches were searched up to 1 October 2022 in the following databases: Pubmed, Scopus, Cochrane Library and Embase. [Platelet rich plasma or platelet or growth factors] and [periodontal] or [bone regeneration or bone defect or bone reconstruction] were used for searching. This study reviewed and analyzed published papers associated with PRP and periodontal bone defect restoration or bone regeneration or bone reconstruction. <b>Results:</b> Different growth factors exhibited varied biological characteristics and function. In-vitro studies, animal experiments and clinical studies confirmed that PRP displayed assorted role in periodontal bone defects repair. The growth factors secreted from PRP can promote new bone formation, soft tissue regeneration and wound healing. The fiber three-dimensional structure in PRP is conducive to the growth and migration of cells and provides strong support for the regeneration of periodontal soft and hard tissues. The anti-inflammatory characteristics of PRP are also closely related to the repair of periodontal bone defects. <b>Conclusion:</b> PRP played an important biological effect on periodontal bone regeneration. The mechanism is closely related to PRP promoting the growth, proliferation, differentiation and migration of periodontal ligament cells and osteoblasts, and the fiber stereo configuration of PRP and the anti-inflammatory effect of leukocytes.