If heart function is normal, the atrial cells are excited in a stable rhythm. But this would change during atrial fibrillation. In this paper, after comparing with the method of characteristic point, we use the dominant frequency method to analyze the activation pattern under sinus and atrial fibrillation rhythm in different parts of atria based on epicardial mapping system. It is found that the activation rhythm changes a lot in different parts of atria, and the automaticity of atrial cells change obviously in somewhere. The result shows that dominant frequency method is very suitable for the analysis of atrial fibrillation signal. What's more, we also roughly discuss the role of this method in exploring the driving sources during atrial fibrillation.
Atrial Fibrillation ; Epicardial Mapping ; Heart Atria ; Humans

Objective To investigate the clinical significance of plasma adrenocorticotropic hormone and cortisol changes at different time in acute cerebral infarction.Methods The clinical data of 62 patients with acute cerebral infarction (acute cerebral infarction group) were analyzed retrospectively,and 60 healthy cases in the same period were recruited as control group.The plasma adrenocorticotropic hormone and cortisol levels at 8:00,16:00 and 24:00 of two groups were detected by electrochemiluminescence immunoassay.Results Plasma adrenocorticotropic hormone and cortisol levels at 8:00,16:00 and 24:00 in acute cerebral infarction group were significantly higher than those in control group [(20.5 ± 4.2) pmol/L vs.(10.4 ±2.6) pmol/L,(18.9 ±4.9) pmol/L vs.(8.5 ± 2.1) pmol/L,(18.1 ±3.8) pmol/L vs.(7.1 ±2.4) pmol/L and (542 ± 76) nmol/L vs.(469 ± 65) nmol/L,(528 ±43) nmol/L vs.(341 ± 33) nmol/L,(499 ± 32) nmol/L vs.(196 ±27) nmol/L](P＜0.05); plasma adrenocorticotropic hormone and cortisol levels of severe degree acute cerebral infarction at different time were higher than those of light conditions (P＜0.05 ); plasma adrenocorticotropic hormone and cortisol levels at different time of acute cerebral infarction patients with good prognosis were significantly lower than those of the persons with poorprognosis(P＜0.05).Conclusion Plasma adrenocorticotropic hormone and cortisol testing at different time has clinical significance in determining the condition and prognosis of patients with acute cerebral infarction.

Vasculogenic mimicry (VM) is one of the blood supply patterns in malignant tumor,and the molecular mechanism of breast malignant tumor VM is complicated.The plasticity of tumor cells and variety of molecules regulation play important roles in the mechanism of VM.At the same time,the hypoxic microenvironment and microRNA (miRNA) are associated with the occurrence and development of VM,especially in breast malignant tumor,and they are expected to become important diagnostic and prognostic indicators in breast cancer.

Objective To study the function of the important members of MMPs in breast cancer and their correlation with lymph nodes metastasis through making groups according to vascular thrombosis status showed by pathological diagnosis and detecting the expression of MMP-2,-9,-13,-14 in order.Methods Fluorescent quantitative RT-PCR was used to detect mRNA expression of MMP-2,-9,-13,-14 in 30 cases of breast cancer patients in both groups (negative and positive vascular thrombosis groups).Streptavidin-peroxidase methods (S-P) immunohistochemical method was employed to detect the expression of ER,PR,HER2,P53 and Ki-67 in breast cancer tissues.The data were analyzed by t test etc.Results Lymph nodes metastasis was significantly more in vascular thrombosis positive group than in negative group(P ＜ 0.05 ).MMP-2 and -13 were overexpressed in vascular thrombosis negative group (P ＜ 0.05).Conclusions Breast cancer patients with positive vascular thrombosis have a more apparent trend of lymph nodes metastasis.MMP-2 and MMP-13 mRNA play a negative regulatory role in intravasation of tumor cells by producing substances that may inhibit tumor angiogenesis and intravasation.

[Objective]To observe the expressional variability and correlation of cox-2 and p53 protein between osteosarcoma and osteochondroma and explore their clinical significance.[Method]Sixty Specimens divided into 2 groups were taken from the department of pathology,Third Hospital of Hebei Medical University during 1998~2004.Among them,40(24 male and 16 female)aged 8~38(18.68?6.47)at time of therapy were from cases of osteosarcoma excision;20(13 male and 7 female)aged 9~27(17.95?4.77)from benign lesion of bone(osteochondroma)operation.Immunohistochemistry staining(Streptavidin-Peroxidasc,S-P method)was performed to detect the expressions of cox-2 protein and p53 protein in 40 cases of osteosarcoma.The criteria of positive expression was that brown granule was found in cytoplasm(cox-2)or in nucleus(p53).The percentage of cox-2 or p53 positive expression in five high power fields was cunted randomly in each case.Positive(-):positive oncocytes account 50%.Software SAS v6.12 was used in data analysis.The difference of cox-2 and p53 expressions between osteosarcoma and osteochondroma was analyzed with Chi-square Test.Spearman method was used,with the standard ?=0.05,to analyze the relationship between cox-2 and p53 expression among osteosarcoma.[Result]The positive rate of cox-2 and p53 expressions were 67.5% and 55.0% in osteosarcoma,there was noticeable distinction between osteosarcoma and osteochondroma,most of them was high.There was a positive correlation between them,rs=0.58,P

BACKGROUND: The aseptic loosening of prosthesis has become one of the most obvious matters after operation of prosthesis replacement. OBJECTIVE: To verify the effect of ibandronate on early fixation of implants by local application. METHODS: Forty-four Zelanian rabbits were used in the experiment. A standard animal model of the rabbits' both tibia was embedded with metal screw into the proximal end. Ibandronate at 1 mg/L was sprinkled locally in the left tibia of every rabbit (experimental group), while saline solution was given in the right tibia (control group). (P < 0.001). These findings indicate that, local application of ibandronate solution can obviously promote new bone formation at the earlier period, improve early fixation of implants and decrease the incidence of aseptic loosening of prosthesis.

Objective To compare and evaluate the defect-repaired capabilities of human bone morphogenetic protein-2(hBMP-2) gene modified tissue engineered bone in the segmental bone defect model of rabbit's radius.Methods Rabbit's bone mesenchymal stem cells (BMSCs)were transferred with hBMP-2 gene through Adeno-XTM adenoviral expression systems,then seeded onto the compound scaffold of calcium phosphate cemept(CPC)and fibrin glue(FG)to construct a new kind of gene modified tissue engineered bone after proliferation in vitro for three weeks(Group A).Meanwhile,the compound scaffold of calcium phosphate cement(CPC)and fibrin glue(FG),which were seeded by rabbit's bone knesenchyrmal stem cells(BMSCs) after proliferation in vitro for three weeks(group B)and the compound scaffold without cells(Group C)acted as control groups.Then,three kinds of reconstructive modalities were implanted into segmental bone defect of donator rabbit's radius.Besides these three groups,bone defect model of rabbit's radius without treatment(Group D)represented blank group.The defect-repaired capabilities were assessed by gross observation,radiograph,Single Photo Emission Computed Topography (SPECT)and histological analysis in the 4th week,8th week and 12th week after operation.The rates of bone healing in the different groups were compared each other.Results All defects that had been treated with implants(Group A,B,C)exhibited new bone formation and could attain osseous tissue healing 12 weeks after operation,but defects in blank group(Group D)were repaired only by fibrous tissue.The defects in the Group A regenerated more new bone,bridged earlier and stronger than those in the Group B and Group C.The quantity and rate of new bone formation in the Group B and Group C had no significant difference and the rates of bone healing in different groups showed the same results.Conclusion hBMP-2 gene modified tissue engineerod bone have better potential to form new bone and the rate of bone healing in repairing bone defects is higher,so this way is an optimal kind of material for artificial bone graft.

BACKGROUND: Tissue-engineered skin plays an important role in the repair and reconstruction of large-area skin lesion. Little is known about the effects of Chinese medicine-loading tissue-engineered skin scaffold on cell adhesion and wound surface infection. OBJECTIVE: To screen the application concentration of shengji solution, which can promote tissue regeneration, using keratinocytes and fibroblasts, and to observe the effects of shengji solution-gelatin-chitosan drug-loading skin scaffold on cellular adhesion and biocompatibility. DESIGN, TIME AND SETTING: Taking keratinocytes and fibroblasts as subjects, the present randomized and controlled experiment was performed at the Laboratory of Cell Engineering, Orthopedic Institute, Tianjin Hospital between February and August 2005. MATERIALS: One healthy big-ear rabbit was included for harvesting skin seed cells. Shengji solution, Danggui (Radix Angelicee Sinensis) and Shengdi (rehmannia dride rhizome) extract (self-extracted, 1.5 g/mL), gelatin-chitosan scaffold and shengji solution-gelatin-chitosan scaffold were provided by Tianjin University, China. METHODS: Passage 3 keratinocytes and fibroblasts were harvested by dispase Ⅱ- trypsase- ethylenediamine tetraacetic acid(EDTA) digestion. The prepared cells were divided into 5 groups: control, shengji solution, Danggui, Shengdi, and epidermal growth factor (EGF). Common culture solution containing 0.1 volume fraction of fetal bovine serum, shengjisolution (5, 6, 8, and 12 g/L), Danggui extract (8 g/L), Shengdi extract (8 g/L), and EGF culture medium (10 μ g/L) were used in corresponding groups for cell culture. At 1, 3, 5, and 7 days, cellular proliferation was detected by methyl thiazolyl tetrazolium (MTT) assay. Keratinocytes and fibroblasts were cultured in different concentrations of shengji solution (50, 60, 80, and 120 g/L) and grouped according to different concentrations. At 7 and 14 days, cellular adhesion was observed by semi-quantitative method. At 4, 7, and 14 days, keratinocytes cultured by 60 and 80 g/L shengji solution were harvested for hematoxylin-eosin staining and subsequent scanning electron microscope observation. MAIN OUTCOME MEASURES: Effects of shengji solution on skin seed cell proliferation; effects of drug-loading scaffold on cellular adhesion; and cell-carrier biocompatibility. RESULTS: MIF detection results demonstrated that cells significantly proliferated after treatment of 5, 6, and 8 g/L shengji solution compared to the control group (P < 0.05). Obvious proliferation of passage 3 keratinocytes and fibroblasts was found on 60 and 80 g/L drug-loading scaffold. Keratinocytes on the drug-loading scaffold exhibited good cellular morphology and closely adhered to the scaffold. Shengji solution had no apparent toxic effects on cells. CONCLUSION: Shengji solution (60 and 80 g/L)-gelatin-chitosan scaffold can effectively promote the adhesion and proliferation of keratinocytes and fibroblasts.

BACKGROUND: Stem cells are relatively primitive cells possessing the capabilities of self-renewal, high proliferation and multi-potential differentiation in vivo under certain conditions. Pancreatic stem cells and umbilical cord blood mesenchymal stem cells (MSCs) may serve therapeutic purpose clinically, but they are still difficult to culture in vitro at present.OBJECTIVE: To explore the method for isolation, purification and culture of pancreatic stem cells and umbilical cord blood MSCs in vitro and observe their morphological changes during culture in vitro.DESIGN: Completely randomized experiment with repeated measurement.SETTING: Stem Cell Research Center, Teaching and Research Division of Physiology, Medical School of Zhengzhou University.MATERIALS: This experiment was conducted in the Stem Cell Research Center, Teaching and Research Division of Physiology, Medical College of Zhengzhou University, between April 2004 and January 2005. Ten to fifteen newborn SD rats (1-3 days) were selected for culture in vitro of pancreatic stem cells, and fresh umbilical cord blood was collected from healthy woman (24-35 years old, with informed consent) at full-term delivery for culture in vitro of umbilical blood SMCs.METHODS: The abdomen of the newborn SD rat was opened under aseptic condition to obtain the pancreas, which was cut into small tissue blocks and digested with type-V collagenase for islet isolation. The isolated islets were purified in continuous roller-bottle culture. Umbilical cord blood was freshly collected for isolating the monocytes by means of density gradient centrifugation in lymphocyte separation medium (with density of 1.077 g/cm3). The islet cells and umbilical cord blood monocytes were cultured in the incubator at 37 ℃ with 5% CO2. The morphological changes of the cells were observed at designed time points and flow cytometry was used to determine the expression of cell surface molecules.MAIN OUTCOME MEASURES: The isolation and culture of pancreatic stem cells and umbilical cord blood MSCs, and their morphological changes during culture in vitro.RESULTS: During culture in vitro, the fusiform islet progenitor cells showed adherent polar growth and continuous proliferation, which covered the whole bottom of the flask after 12-14 days and could be subcultured for passages. However round cells appeared after removal of the growth factor and serum in the culture medium. The monocytes isolated from the umbilical cord blood grew initially into numerous hematopoietic cell clones, most of which proved to be granulocyte clones by Switzerland staining. Seven days later, flat flask wall-adhering epithelial cells and long fusiform fibroblasts were observed mixed with a number of osteoclasts. As the cell culture was prolonged, the cell number increased steadily.CONCLUSION: Pancreatic stem cells and umbilical cord blood SMCs can be cultured in vitro for further experiments.

Objective To develop the accelerated solvent extraction (ASE ) for determ ining pesticides pre-sent in blood sam ples. Methods Pesticides were extracted by ASE with optimized param eters to study recovery rate affected by extraction tem perature, time and agent. GC/MS was used to perform quantita-tive analysis.Results The recovery rates of eight pesticides were 70.6%-92.4%. The coefficient of variation was less than 5.0%. Agood linear relationship was obtained at the concentration range of 0.5-5.0μg/m L . Conclusion The m ethod was fast and sim ple with high recovery rate and good repeatability. It can be applied to analyze pesticides present in the blood specimen.