Clustered regulatory interspaced short palindromic repeats (CRISPR) found in bacteria and archaea genome that contains multiple short repeats loci, provides acquired immunity against invading foreign DNA via RNA-guided DNA cleavage. The first inkling of this hot new genetic engineering tool turned up in 1987, when a research team observed an oddly repetitive sequence at one end of a bacterial gene. Now three types of CRISPR/Cas system have been identified: types I, II and III. In the type II CRISPR/Cas9 system, short segments of foreign DNA termed 'spacers' are integrated within the CRISPR genomic loci, transcribed and processed into short CRISPR RNA (crRNA). These crRNAs anneal to trans-activating crRNA (tracrRNA) and direct sequence-specific cleavage in that a double-strand break (DSB) is generated by Cas proteins. Based on these findings, various genetic methods, including gene targeting (Gene disruption), gene insertion, gene correction etc., are being designed to manipulate the genomes of different species at specific loci. Compared with zinc finger nucleases (ZFN) and transcription activator-like effector nucleases (TALEN), CRISPR/Cas9 is simpler with higher specificity and less toxicity. This review summarizes recent progress, discusses the prospects of CRISPR/Cas9 system, with an emphasis on its structure, principle, applications and potential challenges, and provides a useful reference for researchers who are interested in this new technique.
Bacteria ; CRISPR-Cas Systems ; DNA ; Genetic Engineering ; Genomics ; RNA

Based on the research of risk assessment of medical equipment safety and operation to formulate evaluation criteria and methods of how to use the practical management work. Objective to evaluate the practical method is to use and the risk of adverse events of medical equipment in operation risk in order to find the risk, control risk, ensure safety in time, so that Improve the level of risk management of medical equipment.
Equipment Safety ; Humans ; Risk Assessment ; Risk Management

Vascular dementia (VaD) is one of the most common dementia types in the elderly population. Its incidence is only second to Alzheimer's disease. At present, the diagnosis of VaD mainly based on the clinical manifestations, neuroimaging and neuropsychological scales of the patients. It still lacks higher sensitive and specific metabolism indexes. Magnetic resonance spectroscopy is a noninvasive technique for detecting the energy of living tissues and the changes of metabolism. In recent years, it has been more and more used to patients with VaD and has achieved initial results in the diagnosis, differential diagnosis and cognition-related studies of

Endocannabinoid system has several kinds of receptors, all of which have correspondence ligands and pathways of synthesis and degradation, and they belong to G-protein coupled receptors family. Recently studies show that stimulation of cannabinoid receptors has inhibitory effects on gastrointestinal motility and secretion. In this article, we introduce the compositions of the cannabinoid family members, includingtheir receptors, ligands, and antagonists, and their effects on the gastrointestinal motility and secretion. Useful information can be provided for the further study on the effects of endocannabinoid system on gastrointestinal motility and secretion, providing theoretic evidences for clinical use of cannabinoid.

BACKGROUND:Although cementation of polyethylene liner into a wel-fixed metal shel during the revision surgery has several advantages compared to total acetabular revision, there are some disputes about its clinical outcomes, especialy regarding the re-revision rate and the prosthetic survivorship. OBJECTIVE:To evaluate the clinical outcomes and safety of cementation of polyethylene liner into a wel-fixed acetabular cup in the revision after total hip arthroplasty with retained stable cup. METHODS:Between March 2012 and November 2014, nine patients underwent revision after total hip arthroplasty with cementation of polyethylene liner into a wel-fixed acetabular cup. There were 1 male and 8 females, aged 43.7 years on average. The time was 9.4 years on average from the primary total hip arthroplasty to revision. Harris Hip Score and prosthesis X-ray films were compared after revision. The effects and safety of cementation of polyethylene liner into a wel-fixed acetabular cup were further evaluated. RESULTS AND CONCLUSION:Nine patients were folowed up for 8-37 months. The Harris hip scores before revision was (49.54±18.28) points previously, and (84.82±10.59) points during final folow-up (t=6.377, P < 0.05). One patient had re-revision surgery because of recurrent dislocation. There were not complications in other patients, resulting in failure rate of 11%. These results indicated that polyethylene liner cementation technique is safe and effective when the wel-positioned and wel-fixed acetabular cup retained.

Objective To investigate the expressions of COX-2 and VEGF-C in breast carcinoma and their correlation with lymphangiogenesis and lymph node metastasis. Methods The expressions of COX-2 and VEGF-C and D2-40 were evaluated in 46 cases of breast carcinoma by immunohistochemical staining SP methods. The lymphatic vessels density (LVD) in tumor was counted through the special marker D2-40. Results The positive rate of COX-2 and of VEGF-C was 73.91% (34/46) and 71.74% (33/46) respectively in breast carcinoma tissues. The positive rate of COX-2 and VEGF-C was 86.48% (32/37) and 81.08% (30/37), and LVD was (13.350?3.097)/?200 in the lymph node metastasis group, while that in non-lymph-node metastasis group was 22.22% (2/9), 33.33% (3/9) and (9.560?2.031)/?200 respectively, with significant difference between the two groups (P

This review summarized the current progress in the pathogenesis of leptin-mediated liver disease including fatty liver, hepatitis,fibrosis or cirrhosis. Analysis of leptin effect on activation of hepatic Kupffer cells and hepatic stellate cells was made and molecular mechanism and signal pathways were also discussed.

Methionine dependence is one of characteristic metabolism deficiency in cancer cells.Recently a series of researches focusing on key enzymes of methionine metabolism demonstrated that several molecular events might relate with cancer cell methionine dependence(i.e.,methionine synthasesingle nucleotide polymorphism,methythioadenosine phophorylasegene deletion,down regulation of thymidylate synthase translation;up regulation of methylenetetrahydrofolate reductase expression).Cell apoptosis induced by intracellular signal transduction dysfunction might be another potential mechanism.

Objective To explore the oxidation stress effects of nitrogen monoxide (NO) on rats' hepatic fibrosis induced by carbon tetrachloride (CCl_4). Methods Thirty-four male Wistar rats were subcutaneously given CCl_4 to induce hepatic fibrosis model. Six additional rats were chosen to serve as control group. Histological sections of liver of the animals were stained by H & E and Massons staining. NO in serum, malon-dialdehyde (MDA) and superoxide dismutase (SOD) in liver tissue were determined. Results At 7th week, grade 2 or 3 of hepatic fibrosis was reproduced, in which fibrous tissue formed fibrous septa, around the portal areas stretching into hepatic lobules. The structure of the hepatic lobules was intact or disarranged, but there was no signs of cirrhosis. There was moderate fatty change and vacuolar degeneration of heputocytes. The level of serum NO increased significantly (152.8?12.30?mol/L vs. 11.03?1.95?mol/L, P

The plasma levels of atrial natriuretic factor (ANF), angiotension II (AII, vaso-pressin (VP) and endogenous digitalis-like factor (EDLF) were determined in 23 patients with mi-tral stenosis before and after percutaneous balloon mitral valvuloplasty (PBMV). Before PBMV, the plasma levels of ANF and EDLF were elevated in all patients with lower level of All than nor-mal. After the procedure, with a concomitant decrease of left atrial pressure, the plasma ANF de-creased at 15 minutes (from 317. 4?96. 2 to 164. 9?56. 8ng/L , P