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Biomedical subjects

G Qian

Publications and source records attributed to G Qian.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Malignant transformation of mouse embryonic fibroblast induced by mitochondrial DNA fragments].

OBJECTIVE: To investigate the malignant transforming effect and mechanism of mitochondrial DNA (mtDNA) fragments. METHODS: Tumorigenicity of mtDNA-transformed mouse embryonic fibroblast (NIH3T3) in nude mice was studied using transgenic techniques. Transformed tumors were detected by pathological examination and hybridization signals of mtDNA probe were analyzed by fluorescence in situ hybridization (FISH) techniques. RESULTS: Hybridization signals were observed on the nuclei of 18% - 20% NIH 3T3 cells 1 week after mtDNA fragments transforming. Tumor from mtDNA-transformed NIH 3T3 cells was developed in all 8 nude mice (8/8) respectively 2 weeks after the transformation. The pathological characteristics of the tumors developed were similar to that of fibrosarcoma. CONCLUSIONS: Auto-integration of mtDNA fragments into nuclear genome is a new factor involved in carcinogenesis.

Animals↗
PubMed2000

[Experimental study on suppressive effect of ginkgo extract on adhesion of vascular endothelial cell to monocyte induced by minimally modified low density lipoprotein].

OBJECTIVE: To observe the effect of Ginkgo extract on the interaction between minimally modified low density lipoprotein (MM-LDL) induced human umbilical vein endothelial cell (HUVEC) and U937 monocyte-like cell line. METHODS: The adhesive percentage between HUVEC and U937 by counting and the expression of VCAM-1, ICAM-1, P-selectin by ELISA. RESULTS: Treatment of HUVEC with MM-LDL (75 micrograms/ml) for 4 hrs could significantly increase the adhesion of U937 to HUVEC (P < 0.01) and Ginkgo extract could suppress the adhesion in dose-dependent manner. The surface expression of VCAM-1, ICAM-1, P-selectin was not induced by MM-LDL, while recombination tumor necrosis factor-alpha 5.0 ng/ml, as a positive control, could do. CONCLUSION: Ginkgo extract afforded protection against HUVEC damage induced by MM-LDL and the adhesion of monocytes to endothelial cells induced by MM-LDL is not mediated by VCAM-1, ICAM-1 and P-selectin.

Cell Adhesion↗
PubMed1999

Computing minimum description length for robust linear regression model selection.

A minimum description length (MDL) and stochastic complexity approach for model selection in robust linear regression is studied in this paper. Computational aspects and implementation of this approach to practical problems are the focuses of the study. Particularly, we provide both algorithms and a package of S language programs for computing the stochastic complexity and proceeding with the associated model selection. A simulation study is then presented for illustration and comparing the MDL approach with the commonly used AIC and BIC methods. Finally, an application is given to a physiological study of triathlon athletes.

Algorithms↗
PubMed1999

[The role of apoptosis and Fas/FasL in lung tissue in patients with acute respiratory distress syndrome].

OBJECTIVE: To evaluate the effects of apoptosis and expression of apoptotic related genes on acute respiratory distress syndrome (ARDS). METHODS: Nine patients with ARDS and 5 non-ARDS patients were included. By using TUNEL, histopathology and immunocytochemistry techniques, apoptosis and Fas, FasL protein expression were studied in patients with ARDS in acute stage and in control subjects. RESULTS: Apoptosis ratio was significantly higher in lung tissues in the patients with ARDS than in those of control subjects, especially in alveolar epithelial cells and pulmonary vascular endothelial cells. Fas, FasL protein expression were up-regulated in lung tissues of patients with ARDS. There was a significant correlation between expression of Fas, FasL and ratio of apoptosis. CONCLUSIONS: During the acute stage of ARDS, increase of apoptosis ratio in alveolar epithelial cells and pulmonary vascular endothelial cells, and activation of Fas/FasL system may contribute to the pathogenesis of this syndrome.

Adult↗
PubMed1999

[A preliminary study on the markers of pulmonary vascular endothelial cells in patients with ARDS].

OBJECTIVE: To explore the changes of the markers of pulmonary vascular endothelial cell (PVEC) in patients with ARDS. METHODS: The levels of plasma circulating endothelial cell(CEC), granule membrane protein-140(GMP-140), endothelin-1(ET-1) and von Willebrand factor (vWF) were determined respectively in 13cases of ARDS. The vWF on the surface of the PVEC were stained in 5 cases of ARDS. RESULTS: Circulating CEC, GMP-140, ET-1 and vWF levels were increased significantly (P < 0.01) but scores of vWF expression on the PVEC became weak (P < 0.01) in ARDS samples. The level of plasma GMP-140 elevated dramatically in 2nd day( > 4 times). CONCLUSIONS: PVEC are severely impaired during ARDS. GMP-140 released from PVEC might be a satisfactory criteria for early surveillance and for evaluation of prognosis of ARDS in clinical practice.

Adult↗
PubMed1999

[Systemic inflammatory response syndrome in critical patients - an analysis of 1,292 cases].

OBJECTIVE: To study the significance of the occurrence and the development of systemic inflammatory response syndrome (SIRS) in critical patients. METHODS: The clinical data of 1292 patients accepted by our hospital in ten months from October 1995 to July 1996 were analyzed. The patients met at least two of the criteria for SIRS such as fever, hypothermia, tachycardia, tachypnea or abnormal white blood cell count. RESULTS: 1292 (67.7%) of the 1909 patients investigated met two or more of the criteria for SIRS. In the 1292 cases, those who met two, three or four of the criteria were respectively 467 (36.1%), 526 (40.7%) and 299 (23.1%). 149 patients (11.5%) in the 1292 cases died of multiple organ dysfunction syndrome (MODS). In which 33 (7.1%), 57 (10.8%) and 59 (19.7%) respectively in patients with two, three and four of the criteria for SIRS. The proportion of patients suffering from acute respiratory distress syndrome, metabolic function dysfunction, disseminated intravascular coagulation and acute renal failure increased with the increase in the number of SIRS criteria that the patients met and with the increase in the proportion of patients progressing from SIRS to septic shock. The mortality rate of the patients also gradually increased while the patients with SIRS were developing sepsis, severe sepsis and septic shock, but there was no statistical significance (P > 0.05). CONCLUSION: It is suggested that bacterial infection, severe trauma and acute pancreatitis might cause SIRS and compensatory anti-inflammatory response syndrome might play an important role in the maintenance of internal environment of the body. A comprehensive understanding of SIRS might be of help to the management of critical diseases.

Adolescent↗
PubMed1999

[Clinical application of expandable metal stent for palliation of malignant biliary obstruction].

OBJECTIVE: To investigated the long-term result of expandable metallic biliary stent implantation and evaluated preliminarily the factors that might impact the therapeutic effectiveness. METHODS: 134 patients with malignant choledochal stenosis were treated with metallic endo-prosthesis (128 transpapillary endoscopically and 6 transhepatic percutaneously). The follow-up results were compared with those of 97 patients with conventional plastic stents during the same period. RESULTS: The success rate was 95.7%, and the procedure related complications were found in 6.4% of patients. The jaundice was eliminated completely in 85.6% patients. During long-term follow-up, the metal stents were shown patent for a mean duration of 300 days, which was significantly longer than 80 days of polyethylene endoprostheses (P < 0.01). The mean survival was 210 days. From classified data assessment, the stent patency in primary bile duct neoplasm group was almost similar to that in metastatic group, but the median survival of the former was slightly longer than that of the latter. There were flow differences in patancy and survival rates between the hilar obstruction group and the middle and low obstruction group. CONCLUSIONS: The median patancy of expandable metal stents was significantly longer than that of conventional plastic prostheses. To get the highest benefit, however, the indication should be strictly selected.

Adult↗
PubMed1999

[The role of ICAM-1 in leukocyte adherence to endothelial cells induced by hypoxia/reoxygenation].

OBJECTIVE: To determine whether intercellular adhesion molecule-1 (ICAM-1) mediats the polymorphonuclear leukocyte (PMN) adherence to endothelial cells elicited by hypoxia/reoxygenation (H/R). METHODS: Human umbilical vein endothelial cells (HUVEC) monolayers was exposed to hypoxia for 30 min or 120 min then reoxygenated. Count the number of PMN in adhesion assays. Expression of ICAM-1 and ICAM-1 mRNA was detected by immunohistochemical analysis and in situ hybridization. RESULTS: PMN adhesion to HUVEC exposed to H/R was significantly increased (1 fold) as compared with that of control (P < 0.01). H/R induced hyperadherence was significantly diminished by monoclonal antibodies directed at ICAM-1 or CD11a/CD18. The results showed an increased expression of ICAM-1 and ICAM-1 mRNA on HUVEC exposed to H/R. Hypoxic HUVEC might be responsible for PMN adesion. CONCLUSIONS: ICAM-1 mediated the adhesive interaction between PMN and VEC induced by hypoxia/reoxygenation.

Cell Adhesion↗
PubMed1998

Expression of splice variants of CD44 mRNA and its significance in human primary hepatocellular carcinoma.

OBJECTIVE: To investigate the relationship between the expression of splice variants of CD44 (CD44v) and the metastasis of primary hepatocellular carcinoma (PHCC) in humans. METHODS: The expression of metastasis-associated CD44v mRNA in 54 specimens of human PHCC was detected by reverse transcription and polymerase chain reaction (RT-PCR) method. RESULTS: CD44v mRNA was expressed in 50 (92.59%) of the 54 specimens of PHCC, with moderate or over expression in 42 (77.78%). Among the 42 specimens with moderate or over expression, deficient tumor capsules were found in 25 (59.52%), penetration of tumor capsule in 15 (35.71%), tumor emboli in the portal vein in 34 (80.95%), and daughter tumor nodules in 29 (69.05%). Meanwhile, 12 of the 54 specimens showed negative or weak expression of CD44v mRNA. Of them, all had tumor capsules, 1 (8.33%) had penetrated tumor capsule, 1 (8.33%) had tumor emboli in the portal vein, and 2 (16.67%) had daughter tumor nodules. CONCLUSION: CD44v may contribute to the metastatic potential of PHCC.

Carcinoma, Hepatocellular↗
PubMed1998

[Changes of the deformability of neutrophil and the influence of anisodamine on neutrophil deformability during endotoxin-induced acute lung injury in rats].

OBJECTIVE: To explore the mechanisms of change of deformability of polymorphonuclear leukocytes (PMN) and influence of anisodamine on deformability of PMN during endotoxin-induced acute lung injury (ALI) in rat. To explore the role of PMN in ALI. METHOD: The model of ALI in rat was reproduced by intravenous injection of E Coli endotoxin. The deformability of PMN was measured by micropipette aspiration technique. RESULT: The elastic modulus K1 of PMN at the 1st hour (33 +/- 12 Pa), 4th hours (37 +/- 12 Pa, 1 Pa = 0.0075 mmHg) and 6th hours (38 +/- 13 Pa) after injection of E Coli endotoxin are all significantly higher than that in the control group (26 +/- 9 Pa P < 0.01). The viscosity modulus (mu) of PMN at the 4th hours (5 +/- 3 Pa.s) and 6th hours (6 +/- 3 Pa.s) after injection of E Coli endotoxin are all significantly higher than the control group (3.1 +/- 2.6 Pa.s, P < 0.01). The elastic shear modulus (G) of PMN at the 4th hours (54 +/- 20 Pa) and the 6th hours (56 +/- 21 Pa) after injection of E Coli endotoxin are all significantly higher than the control group (47 +/- 17 Pa, P < 0.05). The K1(33 +/- 12 Pa) and mu(4 +/- 3 Pa.s) in anisodamine group are all significantly lower than endotoxin group in the same time phases (P < 0.05). CONCLUSION: The deformability of PMN decrease remarkably during ALI, which will enhance PMN sequestration in lungs, lead to ALI. It may be one of important pathogenic mechanism of ALI. The anisodamine can inhibit the decrease of deformability of PMN effectively and may have some therapeutic effect on ALI.

Animals↗
PubMed1998

[The detection of circulating hepatocellular carcinoma cells in peripheral venous blood by reverse transcription-polymerase chain reaction and its clinical significance].

OBJECTIVE: To detect circulating hepatocellular carcinoma by demonstrating hepatocellular carcinoma cells-associated mRNA in the nuclear cell component of peripheral blood (PBL). METHOD: Peripheral blood (5 ml) samples were obtained from 93 patients with hepatocellular carcinoma (HCC) and from 37 controls (15 controls with liver cirrhosis after hepatitis B, 12 chronic hepatitis B, and 10 normal liver function). To identify HCC cells in peripheral blood, liver-specific human alpha-fetoprotein (AFP) mRNA was amplified from total RNA extracted from whole blood by reverse transcription-polymerase chain reaction. RESULT: AFP mRNA was detected in 50 blood samples from the patients with HCC (53.8%). In contrast, there were no clinical control patients whose samples showed detectable AFP mRNA in PBL. The presence of AFP mRNA in blood seemed to be correlated with the stage (by TNM classification) of HCC, the serum AFP value, and the presence of intrahepatic metastasis, portal vein thrombosis, tumor diameter and/or distant metastasis. AFP mRNA was detected in the blood of 21 patients showing metastasis at extrahepatic organs (100%) in contrast to 29 of 72 patients without metastasis (40.3%). CONCLUSION: The presence of AFP mRNA in peripheral blood may be an indicator of malignant hepatocytes, which might predict hematogenous spreading metastasis of tumor cells in patients with HCC.

Adult↗
PubMed1997

[Culture and characterization of rat lung microvascular endothelial cells].

Cultures of rat lung microvascular endothelial cells (RLMECs) were obtained from perepheral lung tissue. The lung tissue was cut into small pieces and cultured with RPMI-1640 containing 20% bovine calf serum, 90 micrograms/ml heparin, 4 mmol/L L-glutamine, 100 mu/ml penicillin and 100 micrograms/ml streptomycin. Erythrocytes and leukocytes left the tissue first, followed by RLMECs. Fibroblasts and other cells grew after 72 hours of culture. After 60 hours of culture, the lung tissue was discarded. RLMECs in flask showed regular cobblestone morphology and positive for binding of the lectin Bandeiraea simplicifolia I and indirect immunofluoresence staining with factor VIII antiserum.

Animals↗
PubMed1997

[The application of computer imaging simulation in nose augmentation].

By measurement and analysis, the postoperative image was simulated in standard facial image of the saddle nose using computer imaging and the software developed by us. When the simulated image is accepted by both the surgeon and the patient, the computer gives data to instruct the operation. The authors described how to obtain the standard facial image and how to reduce error. The computer imaging simulation makes the cosmetic operation accurate, quantitative and imaged, and its applications will be broadened.

Adult↗
PubMed1997

[Quantitative determination of dracorhodin in Daemonorops draco B1. and traditional Chinese medicines containing Daemonorops draco B1. by HPLC].

A reversed phase high performance liquid chromatographic mertod for the determination of Dracorhodin in Daemonorops draco B1. and Traditional Chinese Medicines containing Daemonorops draco B1. has been developed so as to set the quality standard for Sichuan Jinyao. The result showed that the components of Dracorhodin were separated by ODS column, with MeOH-0.05 mol/L NaH2PO4 (51:50) (pH = 3.10-3.15, adjusted with H2PO4) acting as the mobile phase. The other high retentive components were eluted by methanol; thus the analytical time was reduced. The method is simple and accurate.

Benzopyrans↗
PubMed1996

Neutralization of SIVmac239/17E in lymphocyte cultures involves virus strain-specific linear and conformational epitopes encoded by different regions of the env gene including the "V3" domain.

SIVmac251 and its closely related derivatives SIVmac239 and SIVmac239/17E vary greatly in their susceptibility to neutralization with homologous and heterologous antisera. Whereas SIVmac251 induces homologous neutralizing antibodies, the antibodies induced by SIVmac239 rarely neutralize infectivity of this virus in lymphocyte cultures. In contrast, SIVmac239/17E is remarkably susceptible to neutralization with homologous and heterologous antisera induced by other strains of SIVmac. In this study, we studied the molecular basis for the neutralization of SIVmac239/17E. Using chimeric viruses in which different regions of the env gene of both SIVmac239 and SIVmac239/17E were inserted into a background of either of the parental genomes, we showed that the newly acquired neutralization properties of SIVmac239/17E were attributable to amino acid substitutions between the V2 and V4 regions of gp 120. Site-directed mutagenesis of the env gene in this region showed that the arginine substitutions at positions 334 and/or 340 within the "V3" domain were fundamental to virus neutralization but other substitutions in the V2-V4 region added to the ease of its neutralization since it became neutralizable with much higher dilutions of serum. The molecular determinants for neutralization of this virus are distinct from those reported as responsible for neutralization of SIVmac251 and both are distinct from SIVmac239.

Animals↗
PubMed1996

The chemical modification of E. coli L-asparaginase by N,O-carboxymethyl chitosan.

E. coli L-asparaginase was modified with N,O-carboxymethyl chitosan in the presence of normal product L-aspartic acid, which protected the active site of the enzyme. The modified enzyme remained high catalytic activity, showed greater stability against trypsin and alpha-chymotrypsin, but lost its activity more rapidly at high temperature (> 45 degrees C) than did the native enzyme. When tested in vivo, the plasma half-life of the modified enzyme (t1/2 = 40 hr) was over 33 times longer than that of the native enzyme (t1/2 = 1.6 hr). The results showed that the modified L-asparaginase may be much more useful than did the native enzyme for clinical treatments of tumors.

Animals↗
PubMed1996

Structure and function of the band 3 Cl-/HCO3- transporter in chronic respiratory failure patients.

OBJECTIVE: To study red blood cell (RBC) membrane band 3 protein structure and anion transport function in cor pulmonale patients with respiratory failure. PATIENTS AND METHODS: Blood samples were obtained from 80 cases of cor pulmonale and 37 normal subjects (control group). The patients were divided into type I respiratory failure (Group I, n = 40) and type II respiratory failure (Group II, n = 40). The anion permeability of the erythrocyte membrane (Pcl), PO2 and PCO2 in 12 of the patients with type II respiratory failure were observed in acute stage (AS), chronic stage (CS) and recovery stage (RS). Membrane protein was analyzed by polyacrylamide electrophoresis in SDS. 55-KDa membrane domain was fractionated on 10% NaDodSO4 polyacrylamide gel column and purified further with a sephadax G-25 column. The composition of amino acids was analyzed on a Beckman 6300 Gold system amino acid analyzer. The Pcl was determined by the hypoisotonic hemolysis method. RESULTS: The relative content of band 3 protein erythrocytic membrane, anion permeability coefficient of the erythrocyte membrane and plasma chloride in the patients with cor pulmonale with type II respiratory failure were significantly lower than those in the patients with type I respiratory failure and the control. The number of residues in the anion transport domain of the trypsin fragment of 55,000 daltons of band 3 protein showed no significant difference among the three groups. CONCLUSIONS: The structure of anion transport sites remains intact and so the reduction of the anion transport function of band 3 protein in patients with cor pulmonale with type II respiratory failure may be due to the decrease of the relative content of band 3 protein, the decrease of extraerythrocytic chloride and hypoxia.

Anion Exchange Protein 1, Erythrocyte↗