Arginase, nitrates, and nitrites in the blood plasma and erythrocytes in hypertension and after therapy with lisinopril and simvastatin

Arginase activity in erythrocytes is higher in patients with arterial hypertension and atherosclerosis as compared with healthy patients. Therapy with either lisinopril alone or in combination with simvastatin for 3–6 months causes a decrease in the arginase activity to the control level. Both the monotherapy and the combination therapy increased the concentrations of N₂⁻, N₃⁻, and total N₂⁻ + N₃⁻ in the plasma of hypertensive patients. The N₂⁻ + N₃⁻ concentration in erythrocytes decreases in hypertensive patients but is completely restored after therapy with lisinopril alone or in combination with simvastatin. Thus, lisinopril and lisinopril plus simvastatin display a pronounced and equal normalizing effect on arginase activity in human erythrocytes, which is elevated in hypertension, as well as on the endothelial nitric oxide synthase activity, which is decreased in hypertension.     

The influence of quality of primers on the formation of primer dimers in PCR

Abstract

Polymerase chain reaction (PCR) is the most commonly used method for nucleic acids amplification. PCR performance depends on several causes, among which the quality of primers is one of the main determinants affecting specificity, sensitivity and reliability of the reaction. Here, we report on the results of the detailed study devoted to the dimerization of the primers during PCR. The course and specificity of the reaction were studied on the model DNA templates as well as genomic DNA using primers that form amplifiable heterodimeric structures with different thermodynamic stability. It was confirmed that more than two 3′-overlapping nucleotides cause a considerable accumulation of primer dimers. It turned out that the presence of any DNA promotes the formation of dimers even for primers, which do not tend to nonspecific amplification in the absence of DNA. It was shown that dimerization could not be eliminated by commonly used techniques. Even the use of hot-start DNA polymerases does not prevent PD formation if primers with stable 3′-overlapping are employed. Despite several advantages of PCR with abutting primers, their close disposition has no benefits regarding the formation of PD if low-quality primers are utilized.