Graphene oxide regulates cox2 in human embryonic kidney 293T cells via epigenetic mechanisms: dynamic chromosomal interactions

To extend the applications of engineered nanomaterials, such as graphene oxide (GO), it is necessary to minimize cytotoxicity. However, the mechanisms underlying this cytotoxicity are unclear. Dynamic chromosomal interactions have been used to illustrate the molecular bases of gene expression, which offers a more sensitive and cutting-edge technology to elucidate complex biological processes associated with epigenetic regulations. In this study, the role of GO-triggered chromatin interactions in the activation of cox2, a hallmark of inflammation, was investigated in normal human cells. Using chromosome conformation capture technology, we showed that GO triggers physical interactions between the downstream enhancer and the cox2 promoter in human embryonic kidney 293T (293T) via p65 and p300 complex-mediated dynamic chromatin looping, which was required for high cox2 expression. Moreover, tumor necrosis factor-α (TNF-α), located upstream of the p65 signaling pathway, contributed to the regulation of cox2 activation through dynamic chromatin architecture. Compared with pristine GO and aminated GO (GO-NH₂), poly (acrylic acid)-functionalized GO (GO-PAA) induced a weaker inflammatory response and a weaker effect on chromatin architecture. Our results mechanistically link GO-mediated chromatin interactions with the regulation of cox2 and suggest that GO derivatives may minimize toxicity in practical applications.     

Peripheral blood leukocyte telomere length is associated with age but not renal function: A cross-sectional follow-up study

Objectives

We aimed to evaluate the relationship between baseline renal function and changes in telomere length in Han Chinese.

Methods

The telomere restriction fragment (TRF) length of leukocytes in the peripheral blood was measured in healthy volunteers recruited in 2014. The estimated glomerular filtration rate (eGFR) was calculated based on serum creatinine (Scr) and serum cystatin C (CysC)-eGFRcys and eGFRScr-cys through the Cockcroft-Gault formula (eGFRC-G) or the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI / eGFRCKD-EPI) equation. The correlation between telomere length changes over time and renal function was analyzed.

Results

Leukocyte TRF lengths were negatively correlated to age (r = -0.393, p < 0.001) and serum CysC (r = -0.180, p < 0.01), while positively associated with eGFRCKD-EPI, eGFRC-G, eGFRcys, and eGFRScr-cys (r = 0.182, 0.122, 0.290, and 0.254 respectively, p < 0.01). The 3-year change of telomere length was 46 bp/years. When adjusted for age, the associations between telomere length changes and baseline, subsequent TRF lengths, and serum CysC were no longer present. No association was observed between TRF length changes and renal function.

Conclusion

The rate of telomere length changes was affected by age and baseline telomere length. The telomere length changes might be important markers for aging.

     

Parent–child separation: the relationship between separation and psychological adjustment among Chinese rural children

Purpose

The current study aimed to explore the characteristics of psychological adjustment among Chinese left-behind children (LBC) in rural areas, and to examine the association between separation duration from parent/parents (SDP) and children’s psychological adjustment and the extent to which personality mediates this hypothesized link.

Methods

We surveyed 534 rural children and adolescents aged 10–17 years at school (440 LBC and 94 non-LBC) in 2013, who were selected for participation using stratified cluster sampling from two counties in Chongqing, China. Measures used included socio-demographic variables, age at the commencement and end of the separation from parents, the revised Chinese Juvenile Eysenck Personality Questionnaire, and the Adolescent Psychological Adaptability Scale.

Results

Most children (82.4%) had experienced separation from parents. t test results showed a marginally significant difference (p?=?.08) in psychological adjustment between LBC (mean?=?64.44, SD?=?8.62) and non-LBC (mean?=?66.16, SD?=?9.26). LBC’s mean SDP was 5.64 years (SD?=?3.90). Correlation analysis showed that children’s SDP was negatively associated with psychological adjustment. Structural equation modeling showed that neuroticism, but not extraversion or psychoticism, fully mediated the link between children’s SDP and psychological adjustment.

Conclusion

Personality (neuroticism) is one of the mediating pathways through which long-term SDP may predict poor psychological adjustment among children. Given the detrimental impact of long-term SDP, interventions should target the mediating pathway to buffer against the negative impact of parental separation on the affected rural children and to improve their mental health.

     

The management of parotid tumors

The majority of salivary gland tumors are of epithelial origin. Parotid gland is the most common location of the tumors. Surgery is the main modality for the management of parotid tumors. Radiotherapy, chemotherapy etc are the auxiliary modalities.     

牙髓干细胞向成牙本质样细胞分化过程中基因表达研究

目的：分离培养来源于人成体牙髓组织的干细胞(dental pulp stem cells，DPSC)，分析研究其在未分化状态及在矿化诱导液中基因表型的变化：方法：采用胶原酶消化法获得人牙髓组织的单细胞悬液，14 d后挑取细胞克隆，分别在普通培养基和矿化诱导培养基中进行培养，利用RT-PCR，图像分析检测细胞基因表型变化。结果。未诱导的DPSC不表达牙本质特异性蛋白(dentin phosphprotein,DSPP)及骨涎蛋白(Bone sialoprotein，BSP)，表达部分成骨(osteocalcin,OCN alkaline phsphatase,ALP)相关表型，低表达转录因子核心结合因子(Cbfa-1)；与末诱导的DPSCs相比较，在成骨诱导中DPSCs表达DSPP和BSP，骨相关基因表达也相应上调。结论：DPsCs在矿化诱导液的作用下向成牙本质样细胞分化，其过程有可能是通过谱系特异表犁的表达或表达上调实现的。     

Gelatinase A (MMP-2) in developing tooth tissues and amelogenin hydrolysis

Matrix metalloproteinases (MMPs) are thought to play important roles during enamel and dentin biomineralization. Previously, membrane type-1 matrix metalloproteinase (MT1-MMP) was localized to the plasma membranes of ameloblasts and odontoblasts of the developing tooth. The best-characterized function of MT1-MMP is to initiate the activation of gelatinase A (MMP-2). Thus, we hypothesized that gelatinase A may also be expressed by developing tooth tissues. A full-length porcine gelatinase A mRNA was isolated by RT-PCR homology cloning of an enamel-organ-specific cDNA library. Northern blot and in situ hybridization analyses demonstrated gelatinase A expression in developing tooth tissues. Immunohistochemical analysis localized gelatinase A close to the plasma membrane of these tissues. Furthermore, recombinant gelatinase A was demonstrated to cleave recombinant amelogenin into several fragments of differing molecular masses. Thus, gelatinase A is expressed by developing tooth tissues along with its activator MT1-MMP and may, therefore, play an important role during tooth development.     

IL—1,IL—6,TNF对人TMJ滑膜细胞蛋白合成的影响

目的：研究人ＴＭＪ滑膜细胞（ＳＭＣ）蛋白质合成能力，与其它组织细胞的差异，及细胞因子对这方面的影响。方法：采用体外培养的ＳＭＣ、ＴＧＣ、ＮＭＣ３种细胞及无血清培养液，应用紫外分光光度仪在２８０ｎｍ波长处，对培养上清中的蛋白含量进行测定，并与加用ＩＬ－１、ＩＬ－６、ＴＮＦ后蛋白质合成的量进行对比观察。结果：正常状态下，ＴＧＣ蛋白合成量最高，ＯＤ值达０．１４，而ＳＭＣ最低，为０．０７９。在加用细胞因子作用４８ｈ后，ＳＭＣ蛋白含量达到０．１１７，提高３０％，而ＴＧＣ、ＮＭＣ却下降１０％～３０％。结论：正常状态下ＳＭＣ合成蛋白质成份较其它细胞少，而细胞因子可刺激ＳＭＣ蛋白质合成增加，这些蛋白成份中可能具有影响关节炎症的物质。     

Bonding properties of universal adhesives to root canals prepared with different rotary instruments

Statement of problem

Preparation of coronal dentin by using a diamond rotary instrument usually results in higher bond strength values than preparation with tungsten carbide burs, but information is lacking about the influence of rotary instruments on root canals before the bonding of fiber posts.