Exercise stress test and comparison of ST change with cardiac nucleotide catabolite production in patients with coronary artery disease

Background: Uridine (Ur) and hypoxanthine (Hx) are the major end products of ischemic nucleotide breakdown in the human heart. Hypoxanthine is further metabolized to uric acid (UA). The aim of the study was the evaluation of whether changes in nucleotide concentrations during exercise correlate with electrocardiography (ECG) changes, and the severity of coronary artery disease (CAD). Methods: Twenty-nine males with CAD and 11 controls without CAD (mean age 56.1 vs. 51.45) were subjected to treadmill exercise. The test was considered positive if ECG showed more then 1 mm ST segment depression. Venous blood samples taken before and 10 minut after the exercise were analysed by high performance liquid chromatography. Results: Twenty-two out of 29 patients with CAD and 6 of 11 in the control group had abnormal exercise stress tests according to ECG criteria only. Mean &#8710;Ur was positive in the CAD group and negative in the control group (0.45 SEM &#177; 0.09 &#181;M/L vs. -0.43 SEM &#177; 0.21 &#181;M/L, p < 0.0001). &#8710;UA was positive in the CAD group (15.31 SEM &#177; 5.52 &#181;M/L) and negative in the control group (15.31 SEM &#177; 5.52 &#181;M/L vs. -48.18 SEM &#177; 13,8 &#181;M/L, p < 0.00001); Hx increased in both groups, and the change was not significantly different. Correlations of CAD-index with ST depression, &#8710;Ur and &#8710;UA, were: r = 0.43 (p < 0.005), r = 0.62 (p < 0.001), and r = 0.39 (p < 0.01), respectively. Sensitivity of any increase of uridine was superior to 1.5 mm ST depression during exercise. Conclusions: Blood Ur and UA concentration changes during exercise correlate with severity of CAD. We observed slightly greater accuracy of uridine change in comparison to ST changes, thus being a possible new tool in diagnosis of CAD. (Cardiol J 2007; 14: 573-579)

Simultaneous determination of lopinavir, saquinavir and ritonavirin in human plasma using liquid chromatography – ion trap mass spectrometry

Background: Lopinavir, saquinavir, and ritonavir are viral protease inhibitors (PIs) developed for and widely used in the therapy of human immunodeficiency virus (HIV)-related disease. These compounds are also active in vitro against the pathogens causing tuberculosis, malaria and coronavirus infections. PIs have been regarded as a platform for the design of inhibitors targeting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-encoded proteases. This study aimed to develop a liquid chromatography/mass spectrometry (LC/MS) procedure for accurate simultaneous determination of concentrations of these three PIs in the plasma. Methods: Samples of human plasma were protein precipitated with 0.3 M zinc sulfate in a water/methanol solution (30:70, v/v). The extracts were analyzed with reversed-phase chromatography coupled with the electrospray ionization (ESI) source of the ion trap mass detector operating in mEass spectrometry (MS) and tandem mass spectrometry (MS/MS) modes. Results: Calibration curves demonstrated good linearity from 0.01 to 10 µg/mL and acceptable reproducibilities and recoveries. Conclusions: The described procedure proves that a very basic ion-trap LC/MS system could be applied for selective, rapid, and precise determination of antiviral protease inhibitors

Narrow time window of metabolic changes associated with transition to overt heart failure in Tgaq*44 mice

Background The timing and consequences of alternations in substrate utilization in heart failure (HF) and their relationship with structural changes remain unclear. This study aimed to analyze metabolic changes associated with transition to overt heart failure in transgenic mouse model of HF resulting from cardiac-specific overexpression of constitutively active Gαq∗. Methods Structural changes quantified by morphometry, relative cardiac mRNA and protein expression of PPARα, FAT/CD36, CPT-1, GLUT-4 and glycolytic efficiency following administration of 1-13C glucose were investigated in 4-14-month-old Tgαq∗44 mice (TG), compared with age-matched FVB wild type mice (WT). Results Initial hypertrophy in TG (4-10-month of age) was featured by an accelerated glycolytic pathway that was not accompanied by structural changes in cardiomyocytes. In 10-month-old TG, cardiomyocyte elongation and hypertrophic remodeling and increased glycolytic flux was accompanied by relatively low expression of FAT/CD36, CPT-1 and PPARα. During the transition phase (12-month-old TG), a pronounced increase in PPARα with an increase in relative fatty acid (FA) flux was associated with anomalies of cardiomyocytes with accumulation of lipid droplets and glycogen as well as cell death. At the stage of overt heart failure (14-month-old TG), an accelerated glycolytic pathway with a decline in FA oxidation was accompanied by further structural changes. Conclusion Tgαq∗44 mice display three distinct phases of metabolic/structural changes during hypertrophy and progression to HF, with relatively short period of increase in FA metabolism, highlighting a narrow metabolic changes associated with transition to overt heart failure in Tgaq∗44 mice that have therapeutic significance