Bioactivation of organic nitrates and the mechanism of nitrate tolerance

Organic nitrates, such as nitroglycerin, are commonly used in the therapy of cardiovascular disease. Long-term therapy with these drugs, however, results in the rapid development of nitrate tolerance, limiting their hemodynamic and anti-ischemic efficacy. In addition, nitrate tolerance is associated with the expression of potentially deleterious modifications such as increased oxidative stress, endothelial dysfunction, and sympathetic activation. In this review we discuss current concepts regarding the mechanisms of organic nitrate bioactivation, nitrate tolerance, and nitrate-mediated oxidative stress and endothelial dysfunction. We also examine how hydralazine may prevent nitrate tolerance and related endothelial dysfunction

Clinical use of the Onclarity test with extended HPV genotyping and phenotyping in patients with suspected squamous intraepithelial lesions

Human papillomavirus (HPV) is the most widespread virus with oncogenic potential that infects humans and there is a need to look for the most effective screening method among the population. Understanding the role of HPV in cervical dysplasia and viruses typing increased the usage of HPV-based cervical cancer screening tests using genotyping. We aim to assess the usefulness the Onclarity Test with extended genotyping and phenotyping of HPV in detecting cervical squamous intraepithelial lesions in 695 subjects who registered for regular cervical screening or due to abnormal LBC result or positive HPV results. Incidence of positive HPV depended significantly on biopsy outcome (p < 0.001). It was the highest for patients with HSIL (92.5%), lower for patients with LSIL (57.9%) and with HPV outcome of biopsy (50.0%). The sensitivity of positive HPV for detecting HSIL was equal to 92.50% (95% CI: 79.61%–98.43%), and specificity equalled 55.26% (95% CI: 43.41–66.69%). Sensitivity of HPV positive for any of 16, 18, 31, 45, 51 or 52 genotypes but not belonging to the P1, P2 or P3 group for detecting HSIL equalled 62.50% (95% CI: 45.80–77.27%), specificity equalled 72.37% (95% CI: 60.91–82.01%). The Onclarity test is characterised by high sensitivity and specificity in detecting CIN2+ lesions. Extended genotyping enables the identification of the most common oncogenic HPV types in the population. It can be used as a basic tool for secondary prevention or together with LBC

Molecular basis of cellulose biosynthesis disappearance in submerged culture of Acetobacter xylinum

Acetobacter xylinum strains are known as very efficient producers of bacterial cellulose which, due to its unique properties, has great application potential. One of the most important problems faced during cellulose synthesis by these bacteria is generation of cellulose non-producing cells, which can appear under submerged culture conditions. The reasons of this remain unknow. These studies have been undertaken to compare at the molecular level wild-type, cellulose producing (Cel+) A. xylinum strains with Cel- forms of cellulose-negative phenotype. Comparison of protein profiles of both forms of A. xylinum by 2D electrophoresis allowed for the isolation of proteins which were produced exclusively by either Cel+ or Cel- cells. Sequences of peptides derived from these proteins were aligned with those of proteins deposited in databases. This analysis revealed that Cel- cells lacked two enzymes: phosphoglucomutase and glucose-1-phosphate uridylyltransferase, which generates UDP-glucose being the substrate for cellulose synthase. DNA was analyzed by ligation-mediated PCR carried out at low denaturation temperature (PCR-MP). Two DNA fragments of different thermal stability (218 and 217 bp) were obtained from the DNA of Cel+ and Cel- forms, respectively. The only difference between these Cel- and Cel+ DNA fragments is deletion of one T residue. Alignment of those two sequences with those deposited in the GenBank database revealed that similar fragments are present in the genomes of some bacterial cellulose producers and are located downstream from open reading frames (ORF) encoding phosphoglucomutase. The meaning of this observation is discussed

Effects of levosimendan on isolated human internal mammary artery and saphenous vein: concurrent use with conventional vasodilators

WOS: 000376151100003PubMed ID: 26839979Graft spasm is a common problem in coronary artery bypass grafting (CABG). In this study, we aimed to investigate the interaction of levosimendan, a novel inodilator, with vasodilator agents that are clinically used for the treatment of graft spasm and with endogenous vasoconstrictors that are thought to play a role in graft vasospasm, in human internal mammary artery (IMA) and saphenous vein (SV). Isolated human IMA and SV segments derived from patients undergoing CABG were suspended in an organ bath. Responses to cumulative concentrations of noradrenaline (NA), serotonin (5-HT), papaverine, nitroglycerin (NG), and diltiazem were recorded before and after 10(-5) m levosimendan incubation (30 min). In addition, cumulative levosimendan responses were taken in vessels precontracted with NA or 5-HT. 10(-5) m levosimendan reduced NA E-max and sensitivity in IMA and SV, and 5-HT E-max responses in IMA. Moreover, levosimendan caused concentration-dependent relaxation in both grafts. Papaverine E-max or sensitivity was not altered by levosimendan neither in IMA nor in SV. Levosimendan diminished NG sensitivity in IMA and E-max responses in SV and decreased diltiazem E-max responses both in IMA and SV. Our results suggest that levosimendan may be used alone for prevention or treatment of graft spasm in IMA or in combination with papaverine in IMA and SV grafts. However, as concurrent administration with diltiazem or NG causes a reduction in relaxation in vitro, we suggest caution should be exercised when using levosimendan in combination with these agents