The Role and Regulatory Mechanism of ZSCAN4 in Early Embryonic and Pluripotent Stem Cells / 中国生物化学与分子生物学报

Zinc finger and SCAN domain containing 4 (ZSCAN4) is specifically expressed as a DNA-binding protein in 2-cell stage embryos and embryonic stem cells. ZSCAN4 regulates early embryonic development by promoting DNA damage repair and correcting chromosomal abnormalities during zygotic genome activation (ZGA) to maintain genomic and chromosomal integrity in preimplantation embryos. During the transition of mouse embryonic stem cells (mESCs) to 2-cell-like cells, ZSCAN4 interacts with ATP-dependent chromatin remodelers to regulate the activity of murine endogenous retroviral L enhancers, and activate the expression of peripheral 2-cell-phase genes to promote the transition of embryonic stem cells to 2-cell-like cells. ZSCAN4 can also promote telomere reorganization and telomere extension by reducing DNA methylation levels to mediate heterochromatin silencing, maintain genome stability and the infinite self-renewal capacity and pluripotency of pluripotent stem cells, and promote mESCs transition to embryonic 2-cell-like cells. In addition, ZSCAN4 can also reactivate early embryonic genes in reprogramming, and significantly increase the generation efficiency of induced pluripotent stem cells (iPSCs). ZSCAN4 reduces DNA damage during iPSCs formation, and preserves genome stability by lengthening telomeres, thereby promoting the generation of high-quality iPSCs without genetic defects. This article focuses on the research advances of the biological functions of ZSCAN4 in regulating early embryonic development, mediating telomere elongation in pluripotent stem cells, and its role in somatic cell reprogramming, which may provide a reference for optimizing the technology to increase the early embryonic development and maintenance of pluripotent stem cells and iPSC generation.

Preparation of paeonol transdermal delivery systems based on proniosomes-based ointment and its pharmacokinetics characters / 中国中药杂志

The paeonol proniosomes ointment and ordinary ointment were administered to rats. Physiological saline served as perfused solution. The perfusion rate was 5 mL x L(-1) and the microdialysis samples were collected every 20 min intervals. The paeonol concentration in perfused solution was determined by HPLC. Investigation of the pharmacokinetics of paeonol proniosomes ointment and ordinary ointment by the skin-blood synchronous microdialysis coupled with HPLC is reported in this study. The results show that the recovery was (54.80 +/- 1.50)% in vitro and (54.58 +/- 4.61)% in vivo. The results showed that paeonol proniosomes ointment significantly raised the drug concentrations in skin more than the paeonol ordinary ointment. The paeono proniosomes ointment has less drugs into the blood as the ordinary ointments in blood, but its blood drug concentrations were steadier. The paeonol proniosomes ointment may be developed into a new preparation.

Construction and expression of non-structural protein gene 3-4b of HCV 1b based on the adenoassociated virus vector / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To clone 1b type of HCV NS3-4b Gene and express in HEK 293 cells, lay the foundation for further study of the HCV NS3-4b recombinant adeno-associated virus vaccine and its dendritic cell vaccine.</p><p><b>METHODS</b>HCV 1b patients' serum was collected, and full length NS3-4b segment was amplified by RT-PCR and cloned into adeno-associated virus' expression vector pAAV. CMV. EGFP in order to express in HEK 293 cells. At last, it was validated whether express or not by Western Blot.</p><p><b>RESULTS</b>The 1b type gene NS3-4b were amplified and consistent to the expected size (2838 bp), the recombinant plasmid has been confirmed its successful restructured by double enzyme and sequencing, at last, Western Blot map can see objective protein expression after it transfect HEK 293 cells.</p><p><b>CONCLUSION</b>The adeno-associsted virus recombination HCV NS3-4b plasmid have successfully constructed and it can express in eukaryotic cells.</p>

The characteristics of masticatory muscle activity in bruxers / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effects of bruxism on masticatory muscle electromyographic (EMG) activity.</p><p><b>METHODS</b>Twenty-four bruxers and sixteen asymptomatic control subjects were included through questionnaire and clinical examination. EMG activity was recorded by placing surface electrodes on bilateral anterior temporalis (TA), masseters (MM), anterior digastrics (DA) and sternocleidomastoid (SCM) muscles. EMG activities at rest, during maximal voluntary clenching in intercuspal position and swallowing were recorded by means of Bio PAK system.</p><p><b>RESULTS</b>EMG activities of TA and MM at rest were significantly higher in bruxism group than in control group (P<0.05). When subjects clenched their teeth in intercuspal position, the activities of TA and MM were much lower in bruxism group than in control one (P<0.05). EMG activity during swallowing was no significant difference between the two groups. The asymmetry index of bilateral TA and MM in bruxism group was a little higher than the control group, but there was no significant difference between the two groups (P>0.05).</p><p><b>CONCLUSION</b>Masticatory muscle dysfunction of bruxers is mainly represented as higher potential in postural position and lower potential during maximal voluntary clenching in intercuspal position of anterior temporalis and masseters.</p>

Palmitic acid induces apoptosis in human hepatoma cell line, HepG2 cells / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the effects of palmitic acid (PA) on human hepatocytes and its mechanism.</p><p><b>METHODS</b>We administered a mimic hyperlipidemia condition of 0.2-0.4 mmol/L PA to human hepatoma cell line, HepG2 cells. Cell viability was determined by Trypan blue staining. Cell cycle and early apoptosis were determined by propidium iodide and/or Annexin V staining, and the levels of Bcl-2 and Bax were analyzed by flow cytometry.</p><p><b>RESULTS</b>An inhibition of cell growth was observed at a dose- and time-dependent manner in HepG2 cells after the treatment of PA. An apoptosis with appearance of sub-G1 fraction determined by cell cycle analysis significantly increased after the treatment of PA for 4 days. Bcl-2 level slightly decreased; in contrast, Bax level elevated markedly, which resulted in a significant decrease of Bcl-2/Bax ratio.</p><p><b>CONCLUSION</b>PA may induce cell death on hepatocytes via mitochondria-mediated apoptosis by reducing the level of Bcl-2/Bax.</p>