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Yan Zhang

Publications and source records attributed to Yan Zhang.

At least 289 records · Page 16Linked to original sources
PubMed2005

Can tumor contrast enhancement be used as a criterion for differentiating tumor grades of oligodendrogliomas?

BACKGROUND AND PURPOSE: The association of high-grade oligodendrogliomas with tumor contrast material enhancement on MR images has been reported. Some authors have even used contrast enhancement as a criterion for their oligodendroglioma grading system. The purpose of our study was to evaluate if tumor contrast enhancement is a specific finding for anaplastic oligodendroglioma. METHODS: Pretreatment MR images of 24 oligodendrogliomas were reviewed retrospectively, and findings were compared with the histologic grade. The presence or absence and the pattern of tumor contrast enhancement were evaluated qualitatively. A contrast enhancement ratio (CER), a quantitative criterion, was calculated to assess the difference in degree of enhancement between the low-grade and anaplastic tumors. Tumor grade was diagnosed at pathologic examination according to the World Health Organization classification system. RESULTS: Contrast enhancement was noted in nine (56%) of 16 low-grade tumors and in five (62%) of eight anaplastic tumors. A characteristic enhancement pattern, nodular-like enhancement, was found in eight tumors. The CERs were 2.12-40.88 (mean, 20.08) in low-grade tumors and were 3.20-62.52 (mean, 28.73) in anaplastic tumors (P > .05). CONCLUSION: Tumor contrast enhancement was not statistically significantly different between the tumor groups. We believe that the presence or absence of tumor contrast enhancement is not a specific finding for simply discriminating low-grade from anaplastic oligodendrogliomas. Histologic confirmation is necessary even in tumors without contrast enhancement.

Adolescent↗
PubMed2005

[Prokaryotic expression vector construction, expression and polyclonal antibody preparation of the fusion protein of glutathione S-transferase and peroxisome proliferator-activated receptor-gamma coactivator-1].

OBJECTIVE: To express the fusion protein of glutathione S-transferase (GST) and peroxisome proliferator-activated receptor-gamma coactivator-1 (PPARgammaC1) in E. coli. and prepare the polyclonal antibody against PPARgammaC1. METHODS: The coding sequence of PPARgammaC1 gene was amplified by reverse transcriptase-PCR (RT-PCR) from the total RNA of Hep G2 cells and inserted into pGEX-4T-1 vector. The recombinant vector was identified by restriction endonuclease digestion analysis and the fusion protein GST-PPARgammaC1 was expressed in E. coli. via IPTG induction. The expressed fusion protein was purified by glutathione-agarose affinity chromatography and used to immunize the egg-laying hens for preparing the polyclonal antibody against GST-PPARgammaC1. RESULTS: Restriction endonuclease digestion analysis demonstrated that the PPARgammaC1 gene had been correctly inserted into pGEX-4T-1 vector, and the expressed fusion protein had a relative molecular mass of approximately 39,000 as shown by SDS-PAGE. The polyclonal antibody obtained from the egg yolk immunoglobulins was found to specifically bind to purified PPARgammaC1 in Western blot analysis. CONCLUSION: The successfully prepared polyclonal antibody against PPARgammaC1 peptide provides a useful reagent for PPARgammaC1 detection.

Antibodies, Monoclonal↗
PubMed2005

[Impaired endothelium-dependent vasodilation and arterial elasticity in patients with coronary artery disease].

OBJECTIVE: To investigate the change in endothelium-dependent vasodilation and arterial elasticity and the association between them in patients with coronary artery disease (CAD). METHODS: Thirty patients with CAD and thirty control subjects were recruited for this study. Flow-mediated dilation (FMD) in the brachial artery was evaluated by ultrasound Doppler flow method. They also underwent a non-invasive assessment of C(1) large artery and C(2) small artery indices by using pulse wave analysis. RESULTS: FMD was significantly reduced in CAD group compared with that in control group [(5.17 +/- 2.13)% vs (11.1 +/- 4.36)%, P < 0.05], C(1) large artery elasticity index was similar between the two groups [(11.59 +/- 4.56) ml/mm Hg x 10 vs (12.11 +/- 3.82) ml/mm Hg x 10, P > 0.05]. However, C(2) small artery elasticity index was significantly reduced in CAD group compared with that in control group [(4.20 +/- 1.80) ml/mm Hg x 100 vs (6.26 +/- 2.36) ml/mm Hg x 100, P < 0.05]. There was a positive association between reduced C(2) small artery elasticity index and impaired FMD (r = 0.53, P < 0.05). CONCLUSIONS: There were impaired endothelium-dependent vasodilation and reduced C(2) small artery elasticity index in the patients with CAD, which were closely correlated with each other. The present study suggested that the measurement of C(2) small artery elasticity might be used as a novel index for the determination of endothelial function.

Aged↗
PubMed2005

[Construction of eukaryotic expression vector of unknown KH gene and its effect on cell proliferation].

OBJECTIVE: To construct an eukaryotic expression vector of open reading frame of unknown KH gene (KH-ORF), and investigate its effect on cell proliferation. METHODS: The pCI-neo-KH-ORF expression vector was constructed by DNA recombinant technique and was introduced into COS-7 cells and K562 cells by lipofectactin-mediated DNA transfection. Expression of KH-ORF mRNA was detected by RT-PCR. The effect of KH-ORF on cell cycle of COS-7 cells and K562 cells was evaluated by flow cytometry (FCM). Effect on cell proliferation of COS-7 cells was tested by MTT assay and that on K562 cells was analyzed by growth curves and LDH activity measurement. RESULTS: (1) KH-ORF mRNA was expressed both in COS-7 cells and K562 cells. (2) The cell cycle and cell proliferation of COS-7 cells were unaffected significantly. (3) The proportion of cells in S phase was increased in pCI-neo-KH-ORF-transfected K562 cells; and growth curves and LDH activity indicated enhanced cell proliferation. CONCLUSION: KH gene may be a leukemia gene related to proliferation of K562 cells.

Animals↗
PubMed2005

[Cytogenetic and clinical study of Philadelphia chromosome positive adult acute leukemia].

To explore the cytogenetics and related clinical characteristics of adult acute leukemia with Philadelphia chromosome positive (Ph(+)AL), MIC classification by morphology, immunology and cytogenetics was used to retrospectively study 79 patients with Ph(+)AL hospitalized in the Institute of Hematology, People Hospital in Beijing from October 1991 to September 2003. The results showed that 6.9% cases were diagnosed as Ph(+)AL and classified into three subtypes: acute lymphoblastic leukemia (Ph(+)ALL) in 56 patients (18%), acute myeloid leukemia (Ph(+)AML) in 10 patients (1.2%) and mixed acute leukemia (Ph(+)MAL) in 13 patients. B-cell antigen expression was found in 52 out of 56 patients with Ph(+)ALL. 54.4% (43/79) patients had additional chromosome abnormalities including chromosome 7, double Ph and plus 8, etc. Complete remission (CR) rate of Ph(+)ALL and Ph(+)MAL was 57.0%, none of Ph(+)AML achieved CR. Median overall survival of Ph(+)ALL, Ph(+)MAL and Ph(+)AML were 10, 10 and 2.5 months respectively. It is concluded that Ph(+)AL has highly heterogeneity involving various differentiated stages of immature leukemic cells. Since the poor prognosis associated with this kind of AL, early diagnosis with MIC classification is a prerequisite to take more effective conditioning regimen and prospectively consideration of allogeneic stem cell transplantation to improve prognosis.

Adolescent↗
PubMed2005

[Forty-three tracheal stricture with Ni-Ti shape memory alloy stent].

OBJECTIVE: To evaluate the application of Ni-Ti shape memory alloy stent for treating tracheal stricture, including its indications and complications. METHODS: Forty-three patients clinical data were analyzed, among them, 15 suffered from tumor; 7 trauma; 4 granulation; 1 Wegener's granuloma, 2 rhinoscleroma, 1 without clear diagnosis; 7 were relapsing polychondritis; 1 were respiratory amyloidosis; 4 were tracheobronchial tuberculosis, 5 were tracheobronchomalacia. The stricture degree: Level I: 15 patients, Level II:24 patients, Level III:4 patients. The location of stricture in 5 patients extended to the subglottis area. All patients had tracheal stricture and accepted the treatment with Ni-Ti shape memory alloy stent. RESULTS: Forty-two patients breathed freely after the operation, 1 patient died after surgery. The tracheostoma in 18 patients was closed 34 days after operation. Among the remaining 8 patients with tracheostoma:3 patients left hospital with tracheal cannula; 1 patient died,2 patients were found stent shifted and no evident breath improving; 2 patients were found granulation and had secondary operation with laser. CONCLUSION: Ni-Ti shape memory alloy stent can expand the tracheal stricture quickly and thus improve the breath effectively, which is minimally invasive and simple. It can be used as a method in the treatment of tracheal stricture.

Adult↗
PubMed2005

[Clinical and cytogenetical study on subacute myeloid leukemia in myelodysplastic syndromes].

OBJECTIVE: To discuss from the clinical and cytogenetic aspect that part of patients now diagnosed as myelodysplastic syndromes (MDS) could be diagnosed early as leukemia and be classified as subacute myeloid leukemia (Sub-AML). METHODS: Totally 173 patients diagnosed as MDS according to FAB or WHO criteria with complete clinical and cytogenetical data were included in this research. Among them 42 had +8 chromosome aberration, 16 had -7/7q-, and 55 had normal karyotypes and more than 0.10 blast cells in the bone marrow. Short term culture and G-banding techniques and in some specimens fluorescence in situ hybridization (FISH) method were used to do chromosome analysis. RESULTS: Among the detected chromosome aberrations, +8 was the most frequent (42.8%) and then -7/7q-(15.0%); 42 patients with +8 had median blast cell count of 0.08, within a median of 18 months follow-up period 40.0% of the patients evolved to frank leukemia (FL) and the median overall survival was 20 months. 16 patients with -7/7q- had higher blast cell count of 0.135; 43.8% of them developed into FL and the median overall survival was only 10 months within a 20-month follow-up period. 55 patients had normal karyotype but a median blast cell count of 0.148; 52.7% of them patients evolved to FL and the median overall survival was 34 months. CONCLUSIONS: Both the +8 and -7/7q- groups have malignant leukemic cell clone, and run a subacute and progressive clinical course; it is suggested they might be classified into Sub-AML. We should keep close watch on the patients who have normal karyotype yet more than 0.10 blast cells, part of whom might suffer from early Sub-AML.

Adolescent↗
PubMed2005

[Inhibitory effect of endostatin mediated by lipofectin on transplanted ovarian cancer].

OBJECTIVE: To study the inhibitory effect of endostatin mediated by lipofectin on transplanted ovarian cancer in nude mice. METHODS: Constructed recombinant vector pVAX1-sEn expressing human endostatin protein was transfected into ovarian cancer cell line 3AO by lipofectin. mRNA of endostatin was detected by RT-PCR. The expression of endostatin in supernatants was detected by enzyme-linked immunosorbent assay (ELISA). The inhibitory effect of pVAX1-sEn on endothelial cell line ECV-204 was detected by methyl thiazolyl tetrazolium (MTT). By use of lipofectin mediated pVAX1-sEn for intratumor injection, the inhibitory effect on growth of ovarian cancer was observed. RESULTS: The result of RT-PCR showed there was a specific band at 610 bp. The expression quantity of endostatin in transfected cell supernatant was (201 +/- 8) ng/ml by ELISA. MTT showed pVAX1-sEn transfected cell supernatant could effectively inhibit the growth of ECV-204, the highest inhibitory ratio was 42%. The tumor volumes in pVAX1-sEn treatment group was (0.85 +/- 0.18) cm(3), significantly smaller than that in normal saline control group (1.90 +/- 0.28) cm(3) and pVAX1 control group (1.78 +/- 0.32) cm(3) (P < 0.05). HE stain in tumor tissue showed that there were obvious necrosis cells in the pVAX1-sEn treatment group, but there were flourishly growing tumor cells in pVAX1 and normal saline control groups. CONCLUSION: pVAX1-sEn mediated by lipofectin can effectively inhibit the growth of ovarian cancer.

Animals↗
PubMed2005

[Studies on the chemical constituents of the essential oil of Artemisia dracunculus].

OBJECTIVE: To analyse the chemical constituents of Artemisia dracunculus. METHOD: The essential oil from A. dracunculus was extracted by steam distillation and the chemical constituents were analysed by capillary GC-MS method. The relative content of each component was calculated by area normalization. RESULT: 36 peaks were separated and all of them were identified. The main chemical components were 3,7-dimethyl-1,3,7-octatriene (38.43%), 1S-alpha-pinene (36.96%), 1-methoxy-4-(2-Propenyl)-benzene (8.57%), limonene (6.33%), 1R-alpha-pinene (3.40%), etc. CONCLUSION: The study provided solid and scientific proof for the further exploitation and utilization of A. dracunculus.

Artemisia↗
PubMed2005

[Primary research of reconstruction of complete biological tissue engineered blood vessel].

To explore primarily the reconstruction of biological tissue engineered blood vessel in vitro, the decellularised scaffolds were obtained from swine common carotid arteries by enzyme digestion, and vascular smooth muscle cells (VSMCs) were isolated from canine thoracic aorta and subcultured and purified. The VSMCs were seeded into the inner surface of scaffolds and they were cocultured in vitro for 4 weeks. Histological staining and transmission electron microscopy were used to observe the growth of canine VSMCs on swine decellularized arterial scaffolds. The results showed the seeded VSMCs grew well on the decellularized scaffold throughout the duration of 4 weeks, which suggests that the method in this article is practicable for reconstructing complete biological tissue engineering blood vessel.

Animals↗
PubMed2005

[An experimental study of recombinant adenovirus microsphere carrying antisense multidrug resistance-associated protein gene for reversing MRP of hepatocellular carcinoma in vitro].

OBJECTIVE: To conduct an in vitro study on the effect of recombinant adenovirus microsphere encapusulated antisense MRP (as-mrp) for use in the gene therapy to overcome drug resistance in hepatocellular carcinoma. METHODS: Recombinant adenovirus microsphere encapusulated as-mrp was transfected into hepatocellular carcinoma multidrug resistance cells HepG2/ADM, the fluorescence intensity of transfected cells were observed at 48 hours and 120 hours after transfection. in vitro drug sensitivity was measured by MTT assay; the resistant index of andromycin resistant variants was determined by drawing the cell dosage reaction curves. The levels of MRP mRNA expression were detected by RT-PCR and the ratio of MRP mRNA/beta-actin was detected. Intracelluar rubidomycin (DNR) concertration was examined by flow cytometry (FCM). RESULTS: More than 90% of the HepG2/ADM cells could be transfected when microspheres being 10 mg. Adv microsphere inhibited the expression of mRNA in HepG2/ADM and enhanced the sensitivity of HepG2/ADM to chemotherapeutic drug. CONCLUSION: Recombinant adenovirus microsphere encapusulated as-mrp could effectively reverse HepG2/ADM cells, which would provide an experimental basis for the methods of reversing the multidrug resistance in human hepatocellular carcinoma.

Adenoviridae↗
PubMed2005

[Extraction and purification of the Klebsiella pneumoniae capsular polysaccharide and the effection on the cell immunoactivity].

Klebsiella pneumoniae was cultured followed by the preparation and immunoactivity elucidating of its polysaccharide (CPS). The lysis of cell is the first key step in the preparation, under the co-action of trypsin, lysozyme and NP-40, the cell lysed within 2h, then the lysate was concentrated by ultrafiltration which serves as concentrating and partial purifying action simultaneously. Crude CPS was got by ethanol precipitation, then purified through the Ion-exchange and gel filtration, the purity of CPS was judged by the gel filtration and agarose gel electrophoresis. The effect of CPS on the cell immunoactivity was studied in detail, the results show that CPS possesses bidirectional immunoregulation on the spleen cells of mice, that is, low concentration of CPS can stimulate the immune response while the high concentration manifests the inhibition significantly. The investigation results will benefit on the exploitation of the CPS.

Animals↗
PubMed2005

[Inhibition of tumor growth in tumor-bearing mice treated with matrine].

OBJECTIVE: To investigate the inhibitory effect of matrine on tumor growth in tumor-bearing mice and explore its possible mechanisms of anti-tumor action in vivo. METHODS: Hepatocellular carcinoma cells H(22) were subcutaneously injected into BALB/c mice and matrine was administered to the tumor-bearing mice. The kinetics of tumor formation and tumor growth were measured, tumor growth inhibition rate (IR) was calculated, and tumor tissue samples were taken and examined by light and electron microscopy to assess the inhibitory effects of matrine on tumor growth in the mice. RESULTS: Marked inhibitory effect of matrine on the transplanted hepatocellular carcinoma H(22) was observed in the tumor-bearing mice. The inhibitory rates were 62.5% and 60.7% in the groups treated with high and low dosage of matrine, respectively (P < 0.01 vs. control group). The tumor formation was significantly retarded and tumor growth was inhibited in matrine-treated groups compared with those in control mice. Histopathological examination revealed widespread necrosis with massive accumulation of infiltrating lymphocytes and plasmacytes in the tumors. Numerous apoptotic cells and apoptotic bodies were observed in the tumors under the electron microscope. CONCLUSION: Matrine has marked inhibitory effects on tumor growth in vivo, which is probably related to inhibition of cell division and tumor cell proliferation, directly killing of tumor cells and/or induction of apoptosis and modulation of anti-tumor immune responses.

Alkaloids↗
PubMed2005

[Effect of HBsAg pulsed dendritic cells on the functions of cytokine-induced killer cells].

AIM: To explore the effects of HBsAg-pulsed dendritic cells (DCs) on the proliferation and killing functions of cytokine-induced killer (CIK) cells. METHODS: The peripheral blood mononuclear cells (PBMCs) were isolated from the patients with chronic hepatitis B by the routine method, and induced into specific DCs with HBsAg pulsed. The (3)H-TdR incorporation method was used to determine the stimulation effect of HBsAg-pulsed DCs on the proliferation of CIK cells. LDH release assay was used to measure the specific killing activity of CIK cells on HepG2215 cells. RESULTS: The HBsAg-pulsed DCs could induce the memory proliferation of CIK cells and strengthen the killing activity of CIK cells (P<0.05). CONCLUSION: HBsAg-pulsed DCs can enhance the proliferation and killing functions of CIK cells.

Cell Line, Tumor↗
PubMed2005

[Study on the relationship between aspirin resistance and incidence of myonecrosis after non-emergent percutaneous coronary intervention].

OBJECTIVE: To investigate the occurrence of aspirin resistance in coronary heart disease (CHD) patients and its influence on myonecrosis among patients undergoing non-emergent percutaneous coronary intervention (PCI). METHODS: 256 CHD patients who have been on aspirin (100 mg/d) for at least 7 days were recruited based on aspirin responsiveness determination. All the patients were divided into two groups: aspirin-resistant group and aspirin-sensitive group. For all patients scheduled for non-emergent PCI, a loading dose of 300 mg of clopidogrel was given at least 12 h before PCI and a 75 mg maintenance dose was given every morning before and after PCI. The incidence of myonecrosis was evaluated by the levels of creatine kinase-myocardial band (CK-MB) and troponin I (TnI) before and after PCI. RESULTS: Aspirin resistance was found in 67 (26.2%) patients and 189 (73.8%) patients were aspirin-sensitive. There was a significantly higher proportion of female subjects in the aspirin-resistant group. The incidence of any CK-MB elevation was 38 (56.7%) in aspirin-resistant group and 42 (22.2%) in aspirin-sensitive group (P < 0.01). The elevation of TnI was observed in 41 (61.2%) of the aspirin-resistant group and in 67 (35.4%) of the aspirin-sensitive group (P < 0.05). Multivariate analysis revealed that aspirin resistance was an independent predictor for CK-MB elevation after PCI (OR = 2.5; 95% CI 1.5 to 6.5; P < 0.05). CONCLUSION: Aspirin resistance exists in some CHD patients, which increases the risk of myonecrosis following non-emergent PCI.

Aged↗
PubMed2005

[Modulation and function of estrogen receptor isoforms alpha and beta in endometrial carcinoma cells].

OBJECTIVE: To explore an efficient way to modulate the expression of estrogen receptor (ER) alpha and beta, and to build up a model of endometrial cancer cell expressing predominantly one isoform of ER and to verify the roles of ER alpha and beta in the tumorigenesis of endometrial cancer associated with estrogen and tamoxifen (TAM). METHODS: A series of oligodeoxyribonucleotides (ODN) against alpha or beta regions of ER alpha or beta were synthesized and tested in human endometrial cancer cell lines (Ishikawa) that express functional ER alpha and beta. The expressions of two ER isoforms were detected by western blot using specific antibodies. Then we studied the change of Ishikawa proliferation in response to 17beta-estradiol and TAM under the influence of antisense ODN. RESULTS: (1) Transfection with antisense ODN directed against the ERalpha and ERbeta could significantly inhibit target protein production. (2) 17beta-estradiol could increase the proliferation of Ishikawa cells, but they lost the ability to proliferate in response to 17beta-estradiol after transfected with ERalpha antisense ODN especially at hours 24, 48 and 72 (P < 0.05). There was no obvious change in cell numbers of Ishikawa in response to 17beta-estradiol which were transfected with ERbeta antisense ODN. (3) TAM could also increase the growth of Ishikawa cells. After transfected with ERalpha antisense ODN, the cells lost the ability to proliferate in response to TAM at hours 24, 48 and 72 (P < 0.05). The inhibition was also seen in Ishikawa cells transfected with ERbeta antisense ODN at hour 72. CONCLUSIONS: (1) Antisense ODN directed against the ERalpha or ERbeta can inhibit the expression of ERalpha or ERbeta effectively. (2) ERalpha may be the primary receptor in the proliferation of Ishikawa cells in response to 17beta-estradiol. Both ERalpha and ERbeta are involved in agonist impact of TAM on endometrial cancer cells.

Cell Line, Tumor↗
PubMed2005

[Heavy metal stabilization in municipal solid waste incineration fly ash using soluble phosphate].

The physico-chemical characteristics of municipal solid waste incineration fly ashes was analyzed. It indicated that the main elements of fly ashes are Ca, Cl, K, S and Si, and many heavy metals such as Pb, Zn, Cu, Mn and Cr can be found in fly ashes, and the heavy metal leaching toxicity such as Pb, Cu, Zn and Cd is much higher than the standards. A new kind of stabilization agent-soluble phosphate is chosen to treat with fly ash, different influence factors including agent dosage, curing time and pH are taken into consideration to test its stabilization for the stabilized fly ash. The experimental results indicate that fly ash treated with soluble phosphate can have excellent stabilization effect, and the leaching toxicity for Pb, Cd and Zn can be reduced by 97.5%, 91.6% and 95.5% at a phosphate dosage of 3%; curing time can not influence its stabilization; and, stabilized fly ash using soluble phosphate can keep long-term stabilization at a broad pH value.

Carbon↗