Feasibility of Subtraction Coronary Computed Tomographic Angiography and Influencing Factor Analysis: a Retrospective Study.

OBJECTIVE: To investigate the feasibility of subtraction coronary computed tomographic (CT) angiography (SubCCTA) to decline calcium artifacts and improve diagnostic accuracy in the presence of coronary calcification and analyze the factors that influence SubCCTA. METHODS: A total of 294 patients suspected of having coronary artery diseases underwent coronary computed tomographic angiography (CCTA) and SubCCTA. Coronary stenoses were blindly evaluated by two experienced radiologists, which were compared with invasive coronary angiography (ICA). Multiple statistical indexes were adopted to analyze the value of SubCCTA for the diagnosis of calcium stenoses. RESULTS: The diagnosable rate of SubCCTA was 67.2% (n=197), and the non-diagnosable rate was 32.8% (n=97). Using SubCCTA, the false positive rate decreased from 56.5% to 17.4%, and the corresponding diagnostic accuracy was increased from 83.6% to 92.9%. Univariate logistic regression analysis showed that height (OR=1.029, 95% CI=1.001-1.058), weight (OR=1.025, 95% CI=1.004-1.046), left ventricular size (OR=1.018, 95% CI=1.007-1.030), cardiothoracic ratio (OR=39.917, 95% CI=1.244-1281.098), the average heart rate (OR=0.866, 95% CI=0.836-0.896) and heart rate range (OR=0.882, 95% CI=0.853-0.912) might be the factors influencing SubCCTA. CONCLUSION: This study suggested that SubCCTA could help improve diagnostic accuracy in the presence of calcium plaques. Moreover, several factors were discovered for the first time to possibly influence SubCCTA, which will be helpful in improving the subtracted image quality.

Protection of cells from nitric oxide-mediated apoptotic death by glutathione C60 derivative.

The influence of the glutathione C60 derivative on the cytotoxicity of a highly reactive free radical NO (nitric oxide) has been investigated. Consistent with its cytoprotective abilities, the derivative scavenges ROS (reactive oxygen species) and RNS (reactive nitrogen species) both in vitro and under cell-free conditions. Moreover, the glutathione C60 derivative protected PC12 cells from the cytotoxic effect of the NO-releasing compound, SNP (sodium nitroprusside). Addition of glutathione C60 derivative alone did not induce apoptosis and necrosis. The results suggest that the glutathione C60 derivative has the potential to prevent NO-mediated cell death without evident toxicity.

Photodynamic anticancer activities of water-soluble C(60) derivatives and their biological consequences in a HeLa cell line.

Photodynamic therapy is an emerging, externally activatable, treatment modality for various diseases, especially for cancer therapy. The photodynamic activities of tumor targeting water-soluble C(60) derivatives (WSFD) were evaluated on HeLa cells. To overcome the poor solubility, biocompatibility and selectivity of C(60), we modified C(60) with l-phenylalanine, folic acid and l-arginine. Consistent with their photodynamic abilities, WSFD generated the reactive oxygen species after irradiation both in water and in vitro. No dark cytotoxicity was observed using 5µg/mL WSFD during long incubation time. Furthermore, the uptake of WSFD into HeLa cells was much more than normal cells, which indicated the WSFD had selectivity to tumor cells. Investigation of the possible photodynamic activities of WSFD demonstrated that they expressed photokilling activities by raising the level of (1)O(2)/O(2)(-) under visible light irradiation. In parallel, following exposure of cells to WSFD and irradiation, a marked decrease in mitochondrial membrane potential, cell viability, activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), as well as increased malondialdehyde (MDA) production were observed. Moreover, WSFD caused significant elevation in caspase-3 activity, and induced apoptotic death. Experiments demonstrated that both chemical properties, such as the chemical structure of adduct and addend numbers, and physical properties, such as degree of aggregation, influenced the ROS-generation abilities, cellular uptake and photodynamic activities of WSFD. The results suggest that WSFD have the potential application in cancer cell inactivation by photodynamic therapy.