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.

Objective: The study investigated the biological effects and molecular mechanisms of platelet-rich plasma (PRP) on periodontal bone regeneration. Methods: 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. Results: 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. Conclusion: 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.

Introduction: Concurrent infections or co-infections in patients diagnosed with Coronavirus Disease-19 (COVID-19) are not uncommon and predict a pejorative prognosis. A co-infection accounts for 1 out of every 5 cases of COVID-19 and increases the likelihood of adverse health outcomes such as mechanical ventilations, ICU admissions, and death. Specifically, Legionella spp. co-infection presents additional challenges in COVID-19 patients because of its rarity, similar clinical presentation to SARS-CoV-2, and poorer outcomes without prompt treatment. Cases Presentation: Case 1. A 62-year-old female presented with a 3-day history of subjective fever and worsening shortness of breath. Room air saturation (saO2) was 70% and improved to 100% on noninvasive positive- pressure ventilation (NIPPV). Lung auscultation revealed rales BL. Chest X –Ray (CXR) showed patchy airspace opacities bilaterally (BL), SARS-CoV-2 PCR and urine legionella antigen tests were positive. The diagnosis of hypoxic respiratory failure secondary to COVID-19 and Legionella pneumonia was made. Patient was admitted to intensive care unit (ICU) and managed with decadron, remdesivir, one unit of convalescent plasma for COVID-19 and Azithromycin for Legionella. Patient subsequently developed acute respiratory distress syndrome (ARDS). ARDS protocol was initiated. 13 days after, the patient was compassionately extubated. Case 2. A 41-year-old male presented with 5-day history of fever, worsening shortness of breath, cough and diarrhea. Patient admitted history of ethanol abuse. SaO2 was 88% and improved on oxygen canula. Lung auscultation revealed rhonchi BL. CXR showed extensive left lung consolidation. Urine test for legionella antigen was positive. COVID-19 PCR was negative, but SARS-CoV-2 IgG was reactive. The diagnosis of Legionnaire disease was made. Despite initial treatment with Azithromycin, patient's hypoxia continued to worsen requiring NIPPV, and subsequently mechanical ventilation in the ICU. The adjunction of empiric treatment for COVID-19 with convalescent plasma, remdesivir and steroids improved both clinicals and laboratory findings. Discussion: The cases illustrated the practical challenges of managing COVID-19 and legionella co- infection. Legionella spp and SARS-CoV-2 overlapping incubation periods and similar clinical presentations and complications. In the absence of diagnosis and treatment, legionella pneumonia has an intrinsic mortality rate of up to 80%. As some COVID-19 mitigation strategies, such as the closure of businesses, have enhanced the conditions for Legionella spp proliferation, the incidence of Co-infection with COVID-19 may increase. We recommend clinicians to have high-indexed suspicion of COVID-19 and Legionella co-infection in order to obtain complete work up at patient’s initial presentation.