Cell cycle checkpoints are protective mechanism responding to DNA damages originated from externalor internal factors. When cells are exposed to genotoxic stress or when nutrition crisis occurs, cell cycleprogression is usually stopped or slowed down by cell cycle checkpoints to allow for DNA repair or for handlingthe crisis. Besides, recent studies suggest that some cell cycle checkpoint proteins are also involved in regulatingphysiological DNA replication via controlling the rate of DNA replication. Cell cycle checkpoint proteins ATR,9-1-1 complex, Chk1, Cdc25A and CDK2 may participate in this process. This kind of regulation is supposed to bevery important for ensuring accurate DNA replication and maintaining genomic stability.

Fluorescence resonance energy transfer (FRET) is the energy transfer from an activated donor fluorophore to a receiving fluorophore. The efficiency of the energy transfer is the function of the distance between the two fluorophores, and is very sensitive to the distance. Its effective response distance is between 1~10 nm, thus it can be used to measure the distance between atoms or molecules. The feature of FRET is very useful in researches on conformational changes, interaction between macromolecules and signal transductions within live cells, and FRET has become a powerful tool in biomedical investigations. However, biological processes often involve interactions between more than two macromolecules, and FRET using two color fluorophores cannot meet the research demand. Recently, two research groups made breakthrough, establishing a novel FRET technique using three color fluorophores based on confocol microscopy and flow cytometry, respectively. The invention will significantly advance researches in biological and related fields.

AIM: To investigate the effect of curcumin on the binding activity of hepatic nuclear factor-kappa B(NF-?B) and the expression of peroxisome proliferator-activated receptor-?(PPAR-?) in rats with liver fibrosis induced by carbon tetrachoride. METHODS: A total of 60 clean male rats were randomly and averagely divided into group A,B,C,D,E and F.The rats in group A served as normal controls,while those in other five groups were injected subcutaneously 40% CCI_4 for seven weeks to induce the model of liver fibrosis.After seven weeks,the rats in group C,D,E,F were intragastrically administered with 50 mg/kg silibinin,100 mg/kg cur,200 mg/kg cur,400 mg/kg cur once per day for six weeks,respectively.HE staining was used to observe the pathological changes of liver tissues under light microscope,and immunohistochemistry and reverse transcriptase polymerase chain reaction(RT-PCR) were performed to detect the activity of NF-?B,PPAR-? and mRNA expression of PPAR-?.RESULTS: The inflammatory and fibrotic degrees were obviously alleviated in group C,D,and E compared with group B.The expression of NF-?B p65 was significantly decreased in liver tissue in group C,D and E,compared with model control group B(P

Humans ; Liver Neoplasms

Objective To investigate risk factors of the adverse event during the fiberoptic bronchoscopy in children and to give some related nursing strategies. Methods Eighty cases were enrolled from pediatric department of the first people's hospital of hangzhou, who were performed by bronchoscope from July 2012 to July 2015, and were divided into the observation group and the control group according to whether appeared the adverse event, with 40 patients each, then univariate and multivariate Logistic regression analysis were adopted. Results Univariate logistic regression analy-sis showed that age, basic disease and operation time were the risk factors of the adverse event during the fiberoptic bronchoscopy in children. Multivariate logistic regression analysis showed that age(OR:16.628,95%CI:1.688-163.764), basic disease (OR:9.369,95%CI:1.429-61.412), operation time (OR:15.252,95%CI:1.767-131.676), were independent risk factors of the adverse event during the fiberoptic bronchoscopy in children. Conclusion More attention should be paid to the younger patients with underlying diseases and long operation time, and corresponding nursing measures should be applied to reduce the adverse event when performed by bronchoscope.

The Rad1 gene is evolutionarily conserved from yeast to human. The fission yeast Schizosaccharomyces pombe Rad1 ortholog promotes cell survival against DNA damage and is required for G(2)/M checkpoint activation. In this study, mouse embryonic stem (ES) cells with a targeted deletion of Mrad1, the mouse ortholog of this gene, were created to evaluate its function in mammalian cells. Mrad1 (-/-) ES cells were highly sensitive to ultraviolet-light (UV light), hydroxyurea (HU) and gamma rays, and were defective in G(2)/M as well as S/M checkpoints. These data indicate that Mrad1 is required for repairing DNA lesions induced by UV-light, HU and gamma rays, and for mediating G(2)/M and S/M checkpoint controls. We further demonstrated that Mrad1 plays an important role in homologous recombination repair (HRR) in ES cells, but a minor HRR role in differentiated mouse cells.
Animals ; Cell Division ; Cell Proliferation ; DNA Damage ; DNA Repair ; Embryonic Stem Cells ; metabolism ; Exonucleases ; genetics ; metabolism ; physiology ; G2 Phase ; Gamma Rays ; Gene Deletion ; Hydroxyurea ; pharmacology ; Mice ; Ultraviolet Rays

Activation-induced cytidine deaminase (AID) is required for the generation of antibody diversity through initiating both somatic hypermutation (SHM) and class switch recombination. A few research groups have successfully used the feature of AID for generating mutant libraries in directed evolution of target proteins in B cells in vitro. B cells, cultured in suspension, are not convenient for transfection and cloning. In this study, we established an AID-based mutant accumulation and sorting system in adherent human cells. Mouse AID gene was first transfected into the human non-small cell lung carcinoma H1299 cells, and a stable cell clone (H1299-AID) was selected. Afterwards, anti-hTNF-α scFv (ATscFv) was transfected into H1299-AID cells and ATscFv was displayed on the surface of H1299-AID cells. By 4-round amplification/flow cytometric sorting for cells with the highest affinities to hTNF-alpha, two ATscFv mutant gene clones were isolated. Compared with the wild type ATscFv, the two mutants were much more efficient in neutralizing cytotoxicity of hTNF-alpha. The results indicate that directed evolution by somatic hypermutation can be carried out in adherent non-B cells, which makes directed evolution in mammalian cells easier and more efficient.
Animals ; Antibody Affinity ; Cells, Cultured ; Cytidine Deaminase ; genetics ; metabolism ; HEK293 Cells ; Humans ; Immunoglobulin Variable Region ; genetics ; immunology ; Mice ; Mutation ; Single-Chain Antibodies ; chemistry ; genetics ; immunology ; Somatic Hypermutation, Immunoglobulin ; genetics ; immunology ; Tumor Necrosis Factor-alpha ; immunology

Traumatic cerebrospinal fluid leakage commonly presents in traumatic brain injury patients, and it may lead to complications such as meningitis, ventriculitis, brain abscess, subdural hematoma or tension pneumocephalus. When misdiagnosed or inappropriately treated, traumatic cerebrospinal fluid leakage may result in severe complications and may be life-threatening. Some traumatic cerebrospinal fluid leakage has concealed manifestations and is prone to misdiagnosis. Due to different sites and mechanisms of trauma and degree of cerebrospinal fluid leak, treatments for traumatic cerebrospinal fluid leakage varies greatly. Hence, the Craniocerebral Trauma Professional Group of Neurosurgery Branch of Chinese Medical Association and the Neurological Injury Professional Group of Trauma Branch of Chinese Medical Association organized relevant experts to formulate the " Chinese expert consensus on the diagnosis and treatment of traumatic cerebrospinal fluid leakage in adults ( version 2023)" based on existing clinical evidence and experience. The consensus consisted of 16 recommendations, covering the leakage diagnosis, localization, treatments, and intracranial infection prevention, so as to standardize the diagnosis and treatment of traumatic cerebrospinal fluid leakage and improve the overall prognosis of the patients.