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Biomedical subjects

Dong Han

Publications and source records attributed to Dong Han.

27 records · Page 2Linked to original sources
PubMed2005

Effects of duration, concentration, and timing of ionomycin and 6-dimethylaminopurine (6-DMAP) treatment on activation of goat oocytes.

The protocol of ionomycin followed by 6-dimethylaminopurine (6-DMAP) is commonly used for activation of oocytes and reconstituted embryos. Since numerous abnormalities and impaired development were observed when oocytes were activated with 6-DMAP, this protocol needs optimization. Effects of concentration and treatment duration of both drugs on activation and development of goat oocytes were examined in this study. The best oocyte activation (87-95%), assessed by pronuclear formation, was obtained when oocytes matured in vitro for 27 hr were treated with 0.625-20 microM ionomycin for 1 min before 6-hr incubation in 2 mM 6-DMAP. Progressional reduction of time for 6-DMAP-exposure showed that the duration of 6-DMAP treatment can be reduced to 1 hr from the second up to the fourth hour after ionomycin, to produce activation rates greater than 85%. Activation rates of oocytes in vitro matured for 27, 30, and 33 hr were higher (P < 0.05) than that of oocytes matured for 24 hr when treated with ionomycin plus 1-hr (the third hour) 6-DMAP, but a 4-hr incubation in 6-DMAP enhanced activation of the 24-hr oocytes. Goat activated oocytes began pronuclear formation at 3 hr and completed it by 5-hr post ionomycin. An extended incubation in 6-DMAP (a) impaired the development of goat parthenotes, (b) quickened both the release from metaphase arrest and the pronuclear formation, and (c) inhibited the chromosome movement at anaphase II (A-II) and telophase II (T-II), leading to the formation of one pronucleus without extrusion of PB2. In conclusion, duration, concentration, and timing of ionomycin and 6-DMAP treatment had marked effects on goat oocyte activation, and to obtain better activation and development, goat oocytes matured in vitro for 27 hr should be activated by 1 min exposure to 2.5 microM ionomycin followed by 2 mM 6-DMAP treatment for the third hour.

Adenine↗
PubMed2005

[Direct bone morphogenetic protein 2 gene therapy for repairing segmental radial defect in rabbits].

OBJECTIVE: To study the effect of direct bone morphogenetic protein 2 (BMP-2) gene therapy mediated by adenovirus on repairing bone defect. METHODS: The radial defect models were made on 60 rabbits, which were evenly divided into 4 groups randomly. The 4 groups were treated with different materials: group A, adenovirus carrying BMP-2 gene (Ad-BMP-2) plus bovine cancellous bone (BCB); group B, reconstructed BMP-2 plus BCB; group C, Ad-Lacz plus BCB; and group D, only BCB scaffolds. The X-ray, histological examination, biomechanics analysis, and immunohistochemical staining were made 4, 8, and 12 weeks after the operation. RESULTS: Group A gained better effect in the volume of new bones, the anti-bending intensity of the healing bone, and the expression of BMP-2 than those of group B. The defect in group A was healed. No new bones were observed in group C and group D. CONCLUSION: Direct BMP-2 gene therapy is easy to perform and has very strong osteo-induction ability. It is a good method to repair segmental bone defects.

Adenoviridae↗
PubMed2004

[Clinical study on treatment of advanced stage non-small cell lung cancer by guben xiaoliu capsule].

OBJECTIVE: To observe the therapeutic effect of Guben Xiaoliu Capsule (GXC) in treating advanced stage non-small cell lung cancer (NSCLC). METHODS: One hundred and ninety-eight NSCLC in-patients were divided into the integrative treated group [Group A, 54 patients treated with chemotherapy (CT) plus GXC], the TCM treated group (Group B, 96 patients treated with GXC alone) and the chemotherapeutic group (Group C, 48 patients treated with CT alone). Randomized controlled observation was applied to the Group A and C. The clinical effect, quality of life (QOL), adverse reaction and survival period in the three groups were observed. RESULTS: The immediate effective rate (CR + PR) in the Group A, B and C was 16.7%, 3.1% and 8.3%, respectively, in the Group A, it was better than that in the other two groups (P < 0.05). The improvement of clinical symptoms and QOL in the Group A and B were superior to those in the Group C (P < 0.05). The median survival rate in the three groups was 12, 15 and 9 months, respectively, the 1-, 2- and 3-year survival rate in Group A being 57.4%, 11.1% and 3.7%, respectively, in Group B, 67.7%, 9.4% and 3.1%, and in (Group C, 39.6%, 4.2% and 0, respectively, comparison between the three groups showed that the survival rates in the former two were higher than those in Group C (P < 0.05). Moreover, the incidence rate and degree of CT toxicity were milder in Group A than those in Group C (P < 0.05). CONCLUSION: GXC has definite effect in treating NSCLC, it could raise the QOL, prolong the survival period of patients, also reduce the toxicity and enhance the efficacy of CT.

Adult↗
PubMed2004

[Effects of sperm and oocyte quality control on intracytoplasmic sperm injection (ICSI) in goats].

ABSTRACT Effects of sperm and oocyte quality control on the efficiency of ICSI of in vitro matured goat oocytes were studied in this paper. The results showed that when injected intracytoplasmically, spermatozoa from caput, corpus and cauda epididymidis resulted in similar rates of fertilization, cleavage and morulae/blastocysts, but when injected subzonally, spermatozoa from caput and corpus gave rise to significantly lower rates of fertilization and embryo development than spermatozoa from the cauda epididymidis and ejaculates. When dead spermatozoa collected from semen that had been preserved in different ways were used for ICSI, those dead from liquid storage at 20 degrees C for 24 h gave rise to the best, but those dead from liquid storage at 5 degrees C for 15 days produced the poorest fertilization and embryo development. When spermatozoa were treated with different concentrations of Triton X-100 before ICSI, significantly higher rates of fertilization, cleavage and morulae/blastocysts were obtained with 0.0005% Triton X-100 than with other concentrations and manual immobilization. Oocytes were classified as of good and poor qualities by treatment in hypertonic sucrose solution, and rates of fertilization and embryo development were significantly higher in the good than in the poor oocytes after ICSI. Post-injection activation of oocytes with either A23187 or ionomycin/6-DMAP significantly increased the rates of fertilization, cleavage and morulae/blastocysts after ICSI. It is therefore concluded that (i) epididymal maturation mainly endowed spermatozoa with the capacity to fuse with the egg plasma membrane; (ii) different methods of semen storage caused different impairment of sperm fertilizing capacity; (iii) pre-injection treatment of spermatozoa with proper concentrations of Triton X-100 might be used to replace manual immobilization for ICSI; (iv) oocyte quality was a major factor influencing the efficiency of ICSI; (v) post-injection activation treatment of oocytes improved fertilization and embryo development after ICSI.

Animals↗
PubMed2003

Time-series observation of the spreading out of microvessel endothelial cells with atomic force microscopy.

The spreading out of microvessel endothelial cells plays a key role in angiogenesis and the post-injury healing of endothelial cells. In our study, a physical force applied with an atomic force microscopic (AFM) cantilever tip in contact mode partly broke the peripheral adhesion that just-confluent cultured rat cerebral microvessel endothelial cells had formed with basal structures and resulted in the cells actively withdrawing from the stimulated area. Time-series changes in cell extension were imaged using tapping mode AFM, in conjunction with total internal reflection fluorescence microscopy, intensified charge-coupled device and field emission scanning electron microscopy. We also interpreted phase images of living endothelial cells. The results showed that formation of a fibronectin molecule monolayer is key to the spreading out of the cells. Lamellipods as well as filopods would spread out in temporal and spatial distribution following the formation of fibronectin layer. In addition, a lattice-like meshwork of filopods formed in the regions leading lamellipods, which would possibly provide a fulcrum for the filaments of the cytoskeleton within the leading cell body periphery.

Animals↗
PubMed2003

14-3-3 connects glycogen synthase kinase-3 beta to tau within a brain microtubule-associated tau phosphorylation complex.

In a recent study, we reported that in bovine brain extract, glycogen synthase kinase-3beta and tau are parts of an approximately 400-500 kDa microtubule-associated tau phosphorylation complex (Sun, W., Qureshi, H. Y., Cafferty, P. W., Sobue, K., Agarwal-Mawal, A., Neufield, K. D., and Paudel, H. K. (2002) J. Biol. Chem. 277, 11933-11940). In this study, we find that when purified brain microtubules are subjected to Superose 12 gel filtration column chromatography, the dimeric scaffold protein 14-3-3 zeta co-elutes with the tau phosphorylation complex components tau and GSK3 beta. From gel filtration fractions containing the tau phosphorylation complex, 14-3-3 zeta, GSK3 beta, and tau co-immunoprecipitate with each other. From extracts of bovine brain, COS-7 cells, and HEK-293 cells transfected with GSK3 beta, 14-3-3 zeta co-precipitates with GSK3 beta, indicating that GSK3 beta binds to 14-3-3 zeta. From HEK-293 cells transfected with tau, GSK3 beta, and 14-3-3 zeta in different combinations, tau co-immunoprecipitates with GSK3 beta only in the presence of 14-3-3 zeta. In vitro, approximately 10-fold more tau binds to GSK3 beta in the presence of than in the absence of 14-3-3 zeta. In transfected HEK-293 cells, 14-3-3 zeta stimulates GSK3 beta-catalyzed tau phosphorylation in a dose-dependent manner. These data indicate that in brain, the 14-3-3 zeta dimer simultaneously binds and bridges tau and GSK3 beta and stimulates GSK3 beta-catalyzed tau phosphorylation.

14-3-3 Proteins↗
PubMed2002

Influence of portal vein and liver artery ligation on the toxicokinetics of soman in rabbits.

The portal vein, liver artery ligation treatment and the portal vein ligation treatment could increase the concentration of P(-) soman in rabbit blood 3.6-19.3 times as compared with soman control group at each time points after soman injection (43.2 microgkg(-1), i.v.). Toxicokinetics parameters showed that portal vein, liver artery ligation treatment and portal vein ligation treatment could reduce the clearance (CL) and distribution volume (V(d)). Meanwhile, they could significantly increase the AUC of soman in rabbits from 2.08+/-0.154 to 18.2+/-2.96 and 22.9+/-3.73 mg s l(-1), respectively. All these data showed that the liver and intestine play a very important role on elimination the free soman in rabbit's blood at high dosing of soman.

Animals↗
PubMed2002

The veA gene activates sexual development in Aspergillus nidulans.

The previously isolated gene complementing the veA1 mutation was confirmed to be the veA gene. The determined nucleotide sequence of the gene demonstrated that there is an open reading frame (ORF) of a 573 amino acid polypeptide. The nucleotide sequence matched some clones of which functions were not assigned yet and the amino acid sequence matched that of Neurospora crassa VeA-related protein with 61% similarity. The nucleotide sequence of the veA1 mutant gene differed from that of the wild type gene by only one nucleotide and the nucleotide G in the initiation codon ATG of the VeA ORF was mutated to the nucleotide T. Then, the mutant ORF may use the 37th methionine codon of the wild type one as a new initiation codon. The veA transcript was present in the conidia and in mycelia cultured for up to 14h and expressed almost constitutively at an increased level throughout the asexual and sexual developmental processes, suggesting that it may act from a relatively early developmental stage. Null mutants of the gene never formed sexual structures, even under conditions where sexual development preferentially occurs in wild types. Over-expressors of the gene formed larger numbers of sexual structures with a much reduced number of conidial heads than a control strain (a veA1 mutant), even under conditions where wild type strains form little sexual structure but form conidial heads very well, such as in the presence of a salt at high concentration. Furthermore, over-expressors could form Hülle cells and cleistothecia, even in a liquid culture. These results indicated that the veA gene is a positive regulator in sexual development and simultaneously a negative one in asexual development.

Amino Acid Sequence↗