The effect of adding lactic acid to canine whole blood on platelet aggregation as measured by impedance aggregometry
VETERINARY CLINICAL PATHOLOGY
Authors: Lawson, Cheryl A.; Spangler, Elizabeth A.
Abstract
Background Acidemia in sick dogs often results from the accumulation of lactic acid. The resulting decrease in blood pH can have many physiologic effects, including alteration of platelet function. Objectives We aimed to evaluate the effect of hyperlactatemia and subsequent acidemia on platelet aggregation in canine blood using impedance aggregometry. Methods Platelet aggregation was measured in blood from 27 healthy dogs using the Multiplate analyzer at baseline and after in vitro addition of two different volumes of lactic acid to adjust the pH. The area under the curve (AUC), reported by the Multiplate analyzer, was used to assess the extent of platelet aggregation in each sample. A linear mixed effects model was used to test for the association between platelet aggregation and pH. The association of baseline platelet aggregation with HCTs, platelet counts, and WBC counts was assessed using Pearson's correlations. Results Acidemia was associated with a significant decrease in platelet aggregation. No significant correlations were detected between platelet aggregation and HCT, platelet count, or WBC count. Platelet aggregation measured using the Multiplate analyzer showed substantial individual variation. Conclusions Worsening acidemia due to the addition of lactic acid caused a mild but significant decrease in platelet aggregation in canine blood. The clinical significance of this change is uncertain but could be important when combined with other abnormalities of hemostasis associated with illness.
Synergistic Supramolecular Effect on the Electro-Oxidation of Biological Relevant Molecules: A Novel Sensor for Simultaneous Determination of Epinephrine and Uric Acid in Human Urine Using MWCNT and a Copper(II) Complex
JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
Authors: Ferraz, Bruno R. L.; Leite, Fernando R. F.; Gomes, Eliziana S.; Sousa, Marcus L.; de Arruda, Eduardo G. R.; Bonacin, Juliano A.; Malagutti, Andrea R.; Formiga, Andre L. B.
Abstract
In this paper a novel supramolecular strategy to improve the efficiency of a voltammetric sensor to determine two biologically relevant molecules (epinephrine (EP) and uric acid (UA)) is presented. The strategy is based on the use of a glassy carbon electrode modified with a copper(II) complex ([Cu(H(2)dimpy)Cl]PF6) adsorbed on multi-walled carbon nanotubes (MWCNTs). The [Cu(H(2)dimpy) Cl]PF6/MWCNT composite-supported electrode was characterized by electrochemical impedance spectroscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The electrocatalytic oxidation of EP and UA using the sensor was investigated by cyclic voltammetry and square wave voltammetry. Under optimized conditions, voltammetric peak currents showed a linear response for the EP and UA concentrations in the ranges 0.5-159.2 and 0.2-58.5 mu mol L-1, whereas the limits of detection were 0.2 and 0.05 mu mol L-1, respectively. The sensor was successfully applied in the selective and simultaneous determination of EP and UA in human urine samples. Thus, our results showed that the supramolecular strategy was successful to build an efficient sensor for simultaneous detection of these molecules in biological samples.