[Evaluation of the color stability of infiltrant resin in comparison to aesthetic composite resins].

OBJECTIVE: To investigate the color stability of infiltrant resin together with three other composites exposed to staining solution. METHODS: Three types of anterior aesthetic composite resins (Filtek Z250, Filtek Z350 XT, and Beautiful Flow Plus F00) and artificial caries with Icon infiltrant resin were used. The samples were randomly divided into two groups (each contained 10 specimens): coffee solution and distilled water immersion for three weeks. Color parameters were deter-mined with the Crystaleye spectrophotometer. RESULTS: Artificial caries lesions infiltrated by Icon showed much higher ΔE than those infiltrated by other aesthetic resins (P<0.05). The discoloration of all the experimental resins and the artificial caries infil-trated with Icon increased with time, but the discoloration on the 1st week was significantly higher than those on the 2nd and 3rd weeks. CONCLUSIONS: Artificial caries infiltrated with Icon was more vulnerable and susceptive to food color than those infiltrated with other aesthetic composite resins.

Long noncoding RNA MEG3 prevents vascular endothelial cell senescence by impairing miR-128-dependent Girdin downregulation.

Long noncoding RNAs (lncRNAs) are commonly associated with various biological functions, in which the function of lncRNA maternally expressed gene 3 (MEG3) has been identified in various cancers. Strikingly, an association between MEG3 with microRNAs (miRNAs), mRNAs, and proteins has been reported. This study investigates the role of MEG3 in vascular endothelial cell (VEC) senescence. Expression of Girdin and miR-128 was monitored in the blood vessel samples of young and old mice/healthy volunteers, along with the measurement of human umbilical vein endothelial cells (HUVECs). The relationship between MEG3/Girdin and miR-128 was determined and verified. Loss- and gain-of-function approaches were applied to analyze the regulatory effects of MEG3 on platelet phagocytosis and lipoprotein oxidation of HUVEC membrane. In addition, the effect of MEG3 on HUVEC senescence was evaluated by detection of the reactive oxygen species, telomerase activity, and telomere length. To further analyze the MEG3-mediated regulatory mechanism, miR-128 upregulation and inhibition were introduced into the HUVECs. Downregulated Girdin and upregulated miR-128 were found in the blood vessels of old individuals and old mice, as well as in senescent HUVECs. MEG3 downregulation was found to be capable of inhibiting Girdin but enhancing miR-128 expression. It was also indicated to inhibit platelet phagocytosis and reduce telomerase activity and telomere length, while enhancing lipoprotein oxidation and reactive oxygen species production, which ultimately contributed in preventing and protecting HUEVCs from senescence. These findings provide evidence supporting that MEG3 leads to miR-128 downregulation and Girdin upregulation, which promotes platelet phagocytosis, thus protecting VECs from senescence.

[Enrichment Levels and Comprehensive Pollution Assessment of Dust Heavy Metals in Winter in Beijing].

Dust reflects the natural subsidence of particles and is thus generally accepted as an important environmental indicator. Dust heavy metals find their way into soil or water via atmospheric deposition, potentially damaging plants, aquatic organisms, as well as human beings. In order to study the concentration levels, enrichment degrees, and comprehensive pollution characteristics of the dust heavy metals Cd, Cr, Pb, Cu, Zn, Ni, Co, V, Bi, and Mo in winter in Beijing, 49 groups of dust samples were collected from different locations within the city from November 2013 to March 2014. Heavy metal content (mass percentage) was then measured using Elan DRC Ⅱ type inductively-coupled plasma mass spectrometry (ICP-MS). Results showed that the average content of Cd, Bi, and Mo was less than 10 mg·kg-1, that of Co, Ni, and V was between 10 and 100 mg·kg-1, while that of Pb, Cr, Cu, and Zn was more than 100 mg·kg-1. The amount of Cd, Zn, and Cu in dust samples was generally higher than their secondary standard values in the soil environment. The secondary standard excess rates of Cd, Zn, and Cu were 100%, 97%, and 93.9% in urban environments, and 100%, 100%, and 81.2% in suburban environments, respectively. Results also indicated slight enrichment of Bi, Cu, Ni, and Pb, mainly derived from crustal or soil sources, while Cd, Cr, Mo, and Zn, exhibited mild enrichment, caused by a combination of natural and artificial sources. The paper proposes a "dust heavy metal comprehensive pollution index" model, based on the traditional single pollution assessment method, so as to explore comprehensive pollution characteristics of dust heavy metals in Beijing. Results for the dust heavy metal comprehensive pollution index in Beijing City were in the order of Cd > Zn > Cu > Pb > Cr > Ni > V > Co. Cd, Zn, Cu, and Pb were identified as key pollution factors, with Cd and Zn as primary factors. Results for the dust heavy metal comprehensive pollution index in Beijing suburbs was Cd > Zn > Cu > Pb > Cr > Ni > Co > V. Cd, Zn, Cu, Pb, and Cr were key pollution factors, with Cd and Zn as primary factors.

[Establishment of an albumin and cytokeratin 19 genetically-modified embryonic stem cell line and evaluation of its hepatoblast differentiation capacities].

OBJECTIVE: To establish a gene-modified embryonic stem (ES; E14.1-2) cell line with hepatoblast differentiation reporter genes, albumin (ALB) and cytokeratin 19 (CK19), labeled to facilitate study of their potential applicability as differentiated hepatoblasts. METHODS: Two expression vectors were constructed, one with the ALB promotor driving the enhanced green fluorescent protein (EGFP) and anti-neomycin genes (pAlb-EGFP), and the other with the CK19 promotor driving the red fluorescence protein and anti-hygromycin genes (pCK19-hCD25-IRES-tdTOMATO). The linearized vectors were electroporated into the E14.1 line, and double reporter genes-modified ES cells (E14.1-2) were selected by neomycin and hygromycin. E14.1-2 hepatoblast differentiation was induced by exposure to growth factors (BMP4 and bFGF) and evidenced by embryoid body formation. Fluorescence-activated cell sorting (FACS) and reverse transcription-polymerase chain reaction (RT-PCR) were used to confirm whether differentiated cells were hepatoblast-like and to quantify the differentiation efficiency. RESULTS: The pAlb-EGFP and pCK19-hCD25-IRES-tdTOMATO vectors were shown to specifically activate ALB and CK19 expression. The E14.1-2 cell line with labeled ALB and CK19 was established, and shown to have pluripotency by RT-PCR detection of pluripotent markers' expression, namely Oct4 and SSEA-1. After 22 days of induction, 21.27% of the differentiated hepatoblasts were detected by FACS as positive for ALB and CK19 expression. CONCLUSIONS: A gene-modified ES cell line was generated with hepatocyte differentiation reporter genes ALB and CK19 labeled. The differentiation of the resultant E14.1-2 line was technically simple to qualify and quantify, and will likely aid future studies of hepatoblast characteristics.