Search

Hemangioma is a benign tumor derived from abnormal blood vessel growth. Unlike other vascular tumor counterparts, a hemangioma is known to proliferate during its early stage but it is followed by a stage of involution where regression of the tumor occurs. The critical onset leading to the involution of hemangioma is currently not well understood. This study focused on the molecular identities of the involution of hemangioma. We demonstrated that a soluble factor released from the involuting phase of hemangioma-derived endothelial cells (HemECs) and identified pigment epithelium-derived factor (PEDF) as an anti-angiogenic factor that was associated with the growth inhibition of the involuting HemECs. The growth inhibition of the involuting HemECs was reversed by suppression of PEDF in the involuting HemECs. Furthermore, we found that PEDF was more up-regulated in the involuting phase of hemangioma tissues than in the proliferating or the involuted. Taken together, we propose that PEDF accelerates the involution of hemangioma by growth inhibition of HemECs in an autocrine manner. The regulatory mechanism of PEDF expression could be a potential therapeutic target to treat hemangiomas. [ABSTRACT FROM AUTHOR]

Greenhouse gas (GHG) emission factors previously reported from various waste incineration plants have shown significant variations according to country-specific, plant-specific, and operational conditions. The purpose of this study is to estimate GHG emissions and emission factors at nine incineration facilities in Korea by measuring the GHG concentrations in the flue gas samples. The selected incineration plants had different operation systems (i.e., stoker, fluidized bed, moving grate, rotary kiln, and kiln & stoker), and different nitrogen oxide (NO x ) removal systems (i.e., selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR)) to treat municipal solid waste (MSW), commercial solid waste (CSW), and specified waste (SW). The total mean emission factors for A and B facilities for MSW incineration were found to be 134 ± 17 kg CO 2 ton −1 , 88 ± 36 g CH 4 ton −1 , and 69 ± 16 g N 2 O ton −1 , while those for CSW incineration were 22.56 g CH 4 ton −1 and 259.76 g N 2 O ton −1 , and for SW incineration emission factors were 2959 kg CO 2 ton −1 , 43.44 g CH 4 ton −1 and 401.21 g N 2 O ton −1 , respectively. Total emissions calculated using annual incineration for MSW were 3587 ton CO 2 -eq yr −1 for A facility and 11,082 ton CO 2 -eq yr −1 for B facility, while those of IPCC default values were 13,167 ton CO 2- eq yr −1 for A facility and 32,916 ton CO 2- eq yr −1 , indicating that the emissions of IPCC default values were estimated higher than those of the plant-specific emission factors. The emission of CSW for C facility was 1403 ton CO 2 -eq yr −1 , while those of SW for D to I facilities was 28,830 ton CO 2 -eq yr −1 . The sensitivity analysis using a Monte Carlo simulation for GHG emission factors in MSW showed that the GHG concentrations have a greater impact than the incineration amount and flow rate of flue gas. For MSW incineration plants using the same stoker type in operation, the estimated emissions and emission factors of CH 4 showed the opposite trend with those of NO 2 when the NO x removal system was used, whereas there was no difference in CO 2 emissions. [ABSTRACT FROM AUTHOR]