Circulating Nucleic Acids in Blood of Healthy Male and Female Donors

Abstract

vanced coronary plaque vulnerability.In case 1, coronary intervention and antiplatelet medication without glycoprotein IIb-IIIa inhibitors was not sufficient to treat severe coronary plaque instability and platelet hyperreactivity, as indicated by excessive and persistent whole-blood hypercholinemia (Ͼ100 mol/L), and the patient died of sudden cardiac death shortly after hospital discharge.In case 2, WBCHO was the only test indicating evolving stent occlusion at an early stage, whereas other biomarkers such as cTnI, myoglobin, D-dimers, and the ECG were nondiagnostic. We were lucky that case 2 returned to the emergency room the next day. The integration of choline testing into routine clinical decisionmaking would have prevented inappropriate discharge from the emergency room. Whole-blood hypercholinemia in the setting of evolving stent thrombosis after clopidogrel withdrawal clearly points to platelet hyperreactivity as a major component for increased WBCHO in this patient.In case 3, high concentrations of WBCHO were present in a massive thrombosis of a coronary bypass graft requiring aspiration-thrombectomy and stent implantation. This case is interesting because it demonstrates that exceptionally high concentrations of WBCHO (Ͼ100 mol/L) may evolve in forms of massive intravascular (platelet) thrombosis, whereas other thrombosis markers (D-dimers) remain low.In contrast to WBCHO concentrations, the PLCHO concentrations were low in all 3 cases. The difference between WBCHO and PLCHO concentrations are explained by several mechanisms: intracellular generation of choline in blood cells by intracellularly located phospholipase D and cell activation pathways (3-7 ), existence of a choline transport system in blood cells (10 ), and the fact that choline is removed to a certain extent from plasma via cellular uptake by other tissues (11 ). PLCHO is also a significant predictor of cardiac events, and concentrations increase in acute coronary syndromes complicated by acute left-ventricular failure and severe tissue ischemia (2 ), which was not evident in these cases. PLCHO concentrations were helpful in identifying the risk associated with phospholipase D activation in these patients more precisely as related to coronary plaque destabilization and coronary platelet thrombosis rather than to tissue ischemia.It should be emphasized that these cases were selected for a discussion on the pathophysiology of whole-blood hypercholinemia in the absence of increased PLCHO and are not suitable for generalized conclusions on the differential clinical value of these markers, which should be based on clinical trials. Individual concentrations of whole blood and plasma choline have to interpreted with respect to the pathophysiology of acute coronary syndromes (12 ). Early biochemical detection of highrisk patients, as presented in these case reports, remains an important issue to target potentially life-saving advanced treatment strategies and to perform coronary angiography and intervention early and with sustained success.

Concentrations of Circulating RNA from Healthy Donors and Cancer Patients Estimated by Different Methods

“…The sensitivity of this method was greater than that of the assay for simultaneous detection of DNA and RNA, developed earlier 14 . The detection limit of the modified assay based on the initial blood volume was 0.75 ng/mL (verses 8 ng/mL) in plasma and 3.2 ng/mL (verses 20 ng/mL in trypsin and 40 ng/mL in PBS–EDTA eluates) 15 . Using this assay we found measurable amounts of cirRNA in about 80% (in contrast to 35%, described earlier) of the plasma samples and at the surface of blood cells of all healthy donors and breast cancer patients.…”

RARβ2 gene methylation level in the circulating DNA from blood of patients with lung cancer

“…The research was approved by Ethics Committee of the Cancer Research Institute. Venous blood samples were stabilized and fractionated into plasma and blood cells (Tamkovich et al, 2005). The csb-cirDNA fractions were obtained as described previously (Tamkovich et al, 2005).…”

“…Venous blood samples were stabilized and fractionated into plasma and blood cells (Tamkovich et al, 2005). The csb-cirDNA fractions were obtained as described previously (Tamkovich et al, 2005). In brief, blood cells were incubated with nine volumes of phosphate buffered saline containing 5 mmol/l of EDTA (PBS/EDTA; 5 min, at room temperature).…”

Protease Activity and Cell-Free DNA in Blood Plasma of Healthy Donors and Breast Cancer Patients

“…The difference between the tumor patients and the controls was statistically significant (Mann-Whitney U test, P < 0.001), coinciding with published data. [30,31] The mechanism of DNA release into the blood circulation occurs either via proliferating or dying cells, such as apoptotic and necrotic cells. [32,33] Naked DNA rapidly degrades in the blood, [34] thanks to the high activity of blood nucleases in order to protect the recipient from foreign nucleic acids.…”

“…However, endogenous cfDNAs have been shown to circulate in the blood for a longer time, [35] as they are protected from nucleases in complexes with histones, [36] blood proteins, [37] apoptotic bodies [38] or bound to the surface of blood cells. [5,31] Blood enzymes that hydrolyze nucleic acid-binding biopolymers can obviously influence the distribution of cfDNA in the blood, provide the release of DNA from tissues or increase the accessibility of cfDNA to nucleases. …”