Diagnostic accuracy of thromboelastometry and its correlation with the HPLC-MS/MS quantification test

The aim of the study was to evaluate the diagnostic accuracy of thromboelastometry for assessing rivaroxaban concentrations. The accuracy of thromboelastometry was compared with the high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method, which is the gold standard for drug plasma monitoring (the reference standard). Forty-six clinically stable patients were treated with 10, 15, or 20 mg of rivaroxaban once daily (OD group) or 15 mg twice a day (BID group) (no particular indication for treatment). Patient samples were collected 2 h after the use of the medication (peak) and 2 h before the next dose (trough). The rivaroxaban plasma concentrations were determined via HPLC-MS/MS, and thromboelastometry was performed using a ROTEM® delta analyzer. There were significant prolongations in clotting time (CT) for the 10, 15, and 20 mg of rivaroxaban treatments in the OD groups. In the 15 mg BID group, the responses at the peak and trough times were similar. At the peak times, there was a positive correlation between the plasma concentration of rivaroxaban and CT (Spearman correlation rho=0.788, P<0.001) and clot formation time (rho=0.784, P<0.001), and a negative correlation for alpha angle (rho=−0.771, P<0.001), amplitude after 5 min (rho=−0.763, P<0.001), and amplitude after 10 min (rho=−0.680, P<0.001). The CT presented higher specificity and sensitivity using the cut-off determined by the receiver characteristics curve. ROTEM has potential as screening tool to measure possible bleeding risk associated with rivaroxaban plasma levels.

Avaliação do potencial fitotóxico de Persea venosa Nees & Mart. (Lauraceae) sobre sementes e plântulas de diferentes espécies cultivadas / Evaluation of the phytotoxic potential of Persea venosa Ness & Mart. (Lauraceae) on seeds and seedlings of different species grown

Este estudo objetiva a análise dos efeitos alelopáticos de Persea venosa (pau-de-andrade) frente a diversas espécies cultivadas. Para os testes, foram utilizados extratos alcoólicos da casca do caule de pau-de-andrade, conforme sua utilização medicinal, em quatro concentrações. A atividade alelopática foi testada frente às cultivares de milho, soja, alface e rabanete. O experimento foi inteiramente casualizado, com quatro repetições de 50 sementes. A análise de cromatografia em camada delgada, utilizando-se sílica como fase estacionária e solventes de diferentes polaridades como fase móvel, foi utilizada para obtenção do perfil fitoquímico, sendo utilizado reveladores específicos para cada classe de metabólitos secundários testada. Observou-se que com o aumento da concentração do extrato de P. venosa, houve o aumento do número de plântulas anormais em todas as cultivares, chegando a percentuais de anormalidade de 100% para milho e soja, 93% para alface e 67,48% para rabanete na concentração de 160 g/L. Ademais, as anormalidades evidenciadas foram predominantes no sistema radicular das plântulas, ocasionando em todos os casos, necrose, truncamento, engrossamento, atrofia e aumento do número de pêlos absorventes. Devido à severidade com que os extratos afetaram o crescimento e a normalidade das plântulas, este estudo evidencia a possibilidade da ocorrência de citotoxicidade por parte da espécie P. venosa, vastamente utilizada na medicina tradicional.

This study aims to analyze the allelopathic effects of Persea venosa (pau-de-andrade) on several cultivars. For the tests, we used alcoholic extracts from the bark of pau-de-andrade, according to their medicinal use in four concentrations. The allelopathic activity was tested on different cultivars of corn, soybeans, lettuce and radish. The experiment was completely randomized, with four replications of 50 seeds. The chromatographic analysis of a thin layer, using silica as the stationary phase and solvents of different polarities as the mobile phase, was used to obtain the phytochemical profile, using specific developers to each class of secondary metabolites tested. It was observed that with an increasing concentration of the extract of P. venosa, there was an increase in the number of abnormal seedlings in all cultivars, reaching percentages of abnormality of 100% for corn and soybeans, 93% for lettuce, and 67.48% for radish at a 160 g/L concentration. Furthermore, the evidenced abnormalities were predominant in the seedling root system, causing, in all cases, necrosis, truncation, atrophy and increased number of hairs. Due to the severity with which the extracts affected the growth of seedlings and their normality, this study highlights the possible occurrence of cytotoxicity by the P. venosa species, which is widely used in traditional medicine.