Biomedical subjects

S Liu

Publications and source records attributed to S Liu.

At least 181 records · Page 10Linked to original sources

PubMed2001

The effect pathway of retinoic acid through regulation of retinoic acid receptor alpha in gastric cancer cells.

AIM: To evaluate the role of RARalpha gene in mediating the growth inhibitory effect of all-trans retinoic acid (ATRA) on gastric cancer cells. METHODS: The expression levels of retinoic acid receptors (RARs) in gastric cancer cells were detected by Northern blot. Transient transfection and chlorophenicol acetyl transferase (CAT) assay were used to show the transcriptional activity of beta retinoic acid response element (betaRARE) and AP-1 activity. Cell growth inhibition was determined by MTT assay and anchorage-independent growth assay, respectively. Stable transfection was performed by the method of Lipofectamine, and the cells were screened by G418. RESULTS: ATRA could induce expression level of RARalpha in MGC80-3, BGC-823 and SGC-7901 cells obviously, resulting in growth inhibition of these cell lines. After sense RARalpha gene was transfected into MKN-45 cells that expressed rather low level of RARalpha and could not be induced by ATRA, the cell growth was inhibited by ATRA markedly. In contrast, when antisense RARalpha gene was transfected into BGC-823 cells, a little inhibitory effect by ATRA was seen, compared with the parallel BGC-823 cells. In transient transfection assay, ATRA effectively induced transcriptional activity of betaRARE in MGC80-3, BGC-823, SGC-7902 and MKN/RARalpha cell lines, but not in MKN-45 and BGC/aRARalpha cell lines. Similar results were observed in measuring-antiAP-1 activity by ATRA in these cancer cell lines. CONCLUSION: ATRA inhibits the growth of gastric cancer cells by up-regulating the level of RARalpha RARalpha is the major mediator of ATRA action in gastric cancer cells; and adequate level of RARalpha is required for ATRA effect on gastric cancer cells.

Agar↗

PubMed2001

Recombinant single chain cardiac troponin I-C polypeptides: superior calibration and control materials for cardiac troponin I immunoassays.

There has been a need to create stable and reproducible calibration and control materials for cardiac troponin I assays. Free troponin I, native or recombinant, has been known to be unstable, while troponin CI complex can be easily dissociated in low concentrations or in the presence of chelating agents. In order to overcome these difficulties, two single chain troponin I-C polypeptides have been engineered and expressed separately in Escherichia coli. One consists of a full-length of human cardiac troponin I and C, termed as ScTnI-C and the other consists of a stable fragment (aa28-110) of human cardiac troponin I and a full-length troponin C, termed as ScTnI-C-2. Both ScTnI-C and ScTnI-C-2 were purified to homogeneity by affinity chromatography using anti-cTnI monoclonal antibodies. ScTnI-C and ScTnI-C-2 have apparent molecular weights of 45 kD and 30 kD by SDS-PAGE, respectively. Stability studies by Stratus showed that ScTn I-C and ScTnI-C-2 were stable for 4 months at 2-8 degrees C and at least one year at -20 degrees C. When incubated in human serum at 37 degrees C, ScTnI-C-2 was more resistant to proteolysis than ScTnI-C. ScTnI-C can be recognized by all commercial TnI immunoassays with excellent activity. ScTnI-C-2 can be recognized by all immunoassays that target the stable region of cardiac troponin I. Judging by their performances, ScTnI-C and ScTnI-C-2 are both superior materials to be used as calibrators and controls in clinical laboratories.

Antibodies, Monoclonal↗

PubMed2001

Measures of cell turnover (proliferation and apoptosis) and their association with survival in breast cancer.

Our objective was to investigate the prognostic significance of cell turnover (apoptosis and proliferation) in breast cancer patients. Apoptosis was microscopically quantitated on histological sections from 791 breast cancer patients with long-term follow-up (median, 16.3 years). Apoptotic counts were also compared with proliferation data (mitotic counts and MIB-1 labeling); apoptosis data derived from terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay; and pathobiological variables, including p53, erbB-2, and estrogen receptor (ER). High apoptotic counts were associated with increased cellular proliferation, ER negativity, immunopositivity of erbB-2 and p53 (P < 0.0001), and shortened disease-specific survival (DSS; P = 0.0009) and disease-free survival (DFS; P = 0.0006). Other factors associated with shortened DFS and DSS by univariate analysis were high tumor grade, nodal metastases, and large tumor size (P < 0.0001 for each). Multivariate analysis of data for all of the patients demonstrated that tumor size, nodal status, ER, histological grade, and erbB-2 showed independent prognostic value. In node-negative patients, tumor size and mitotic rate per 1000 cells independently predicted DFS (P = 0.0055). Tumor grade was the only independent predictor of DSS. For node-positive patients, tumor size, nodal status, ER, and erbB-2 were independent prognostic factors. The number of mitoses per 1000 was independently associated with DFS (P = 0.043) but not with DSS. Apoptosis data did not provide independent prognostic value in any, node-positive or node-negative, breast cancer patients.

Adult↗

PubMed2001

[Design and improvement of stenosis model in cylindrical tubal flow via pulsed Doppler ultrasound in vitro].

A model of disturbed flow downstream of a severe stenosis has been established and improved in vitro, and the relevant method and feasibility for the detection of flow indices are discussed via commercially available Pulsed Doppler Ultrasound (PDU). Detection is done temporally and spatially, upstream and downstream. The methodology is proved to be feasible and has good prosperity of clinical use.

Constriction, Pathologic↗

PubMed2001

Diagnostic performance of antineutrophil cytoplasmic antibody tests for idiopathic vasculitides: metaanalysis with a focus on antimyeloperoxidase antibodies.

OBJECTIVE: The diagnostic value of tests for antimyeloperoxidase antibodies (anti-MPO) for systemic vasculitis is less established than that for cytoplasmic antineutrophil cytoplasmic antibody (cANCA)/antiproteinase 3 antibodies (anti-PR3). Controversy exists regarding the optimal utilization of indirect immunofluorescence (IIF) ANCA testing versus antigen-specific ANCA testing. To summarize the pertinent data, we conducted a metaanalysis examining the diagnostic value of ANCA testing systems that include assays for anti-MPO. METHODS: We performed a structured Medline search and reference list review. Target articles in the search strategy were those reporting the diagnostic value of immunoassays for anti-MPO for the spectrum of systemic necrotizing vasculitides that includes Wegener's granulomatosis, microscopic polyangiitis, the Churg-Strauss syndrome, and isolated pauci-immune necrotizing or crescentic glomerulonephritis, regardless of other types of ANCA tests. Inclusion criteria required specification of a consecutive or random patient selection method and the use of acceptable criteria for the diagnosis of vasculitis exclusive of ANCA test results. Weighted pooled summary estimates of sensitivity and specificity were calculated for anti-MPO alone, anti-MPO + perinuclear ANCA (pANCA), and anti-MPO/pANCA + anti-PR3/cANCA. RESULTS: Of 457 articles reviewed, only 7 met the selection criteria. Summary estimates of sensitivity and specificity (against disease controls only) of assays for anti-MPO for the diagnosis of systemic necrotizing vasculitides were 37.1% (confidence interval 26.6% to 47.6%) and 96.3% (CI 94.1% to 98.5%), respectively. When the pANCA pattern by IIF was combined with anti-MPO testing, the specificity improved to 99.4%, with a lower sensitivity, 31.5%. The combined ANCA testing system (anti-PR3/cANCA + anti-MPO/pANCA) increased the sensitivity to 85.5% with a specificity of 98.6%. CONCLUSION: These results suggest that while anti-MPO is relatively specific for the diagnosis of systemic vasculitis, the combination system of immunoassays for anti-MPO and IIF for pANCA is highly specific and both tests should be used together given the high diagnostic precision required for these conditions. Because patients with ANCA associated vasculitis have either anti-MPO with pANCA or anti-PR3 with cANCA, and rarely both, a combined ANCA testing system including anti-PR3/cANCA and anti-MPO/pANCA is recommended to optimize the diagnostic performance of ANCA testing.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed2001

Integrin activation.

Integrins are cell surface adhesion receptors that participate in a variety of important processes throughout the vasculature. Here we summarize some recent findings on the regulation of integrin mediated cellular adhesion. Particular emphasis is placed on the regulation of integrin affinity for ligand (activation), although this is just one mechanism by which regulation of integrin-dependent cell adhesion can occur. Also discussed are recent observations on the structural basis of integrin activation, the role of the cytoplasmic domain in integrin affinity regulation, and potential mechanisms by which activation signals are propagated from integrin cytoplasmic domains to the extracellular ligand binding domain.

Amino Acid Sequence↗

PubMed2001

Gelsolin as a negative prognostic factor and effector of motility in erbB-2-positive epidermal growth factor receptor-positive breast cancers.

PURPOSE: erbB-2 and epidermal growth factor receptor (EGFR) may mediate motility via signaling that enables changes in the actin cytoskeleton. A physical basis for this motility may depend on the coexpression of gelsolin, a M(r) 80,000 actin-binding protein. EXPERIMENTAL DESIGN: The expression of erbB-2, EGFR, and gelsolin was analyzed in 790 archival invasive breast cancers. These data were compared with histological, clinical, and outcome data (median follow-up, 16.3 years). RESULTS: Protein overexpression was observed in overlapping subsets of breast cancers (38% of cases were erbB-2+; 15% of cases were EGFR+; and 56% of cases were gelsolin+). Tumor gelsolin was associated with overexpression of erbB-2 and EGFR, as well as with an aggressive tumor phenotype. By univariate and multivariate analyses, tumor gelsolin alone was not a prognostic factor. Overexpression of all three factors significantly predicted poor clinical outcome by univariate and multivariate analyses. For example, in node-positive patients, coexpression of all three markers was associated with a 3-year disease-specific survival (as compared with erbB-2+, EGFR+, gelsolin- patients, who had a median survival of 6 years). CONCLUSIONS: These data suggest that gelsolin coexpression may be an important additional prognostic factor in erbB-2+, EGFR+ breast cancer patients. We hypothesize that this is due to the role of gelsolin in mediating motility and invasion.

Adult↗

PubMed2001

The hepatocyte as a microbial product-responsive cell.

Much research has focused on the responses to microbial products of immune cells such as monocytes, macrophages, and neutrophils. Although the liver is a primary response organ in various infections, relatively little is known about the antimicrobial responses of its major cell type, the hepatocyte. It is now known that the recognition of bacteria occurs via cell-surface proteins that are members of the Toll-like receptor (TLR) family. In addition, lipopolysaccharide (LPS) is bound by circulating LPS-binding protein (LBP) and presented to cell-surface CD14, which in turn interacts with TLR and transduces an intracellular signal. We investigated the CD14 and TLR2 responses of whole liver and isolated hepatocytes, and demonstrated that these cells can be induced to express the molecules necessary for responses to both Gram-positive and Gram-negative bacteria. Our findings may have clinical implications for pathological states such as sepsis.

Acute-Phase Proteins↗

PubMed2001

[Arthropod community structures in transgenic Bt cotton fields].

Arthropod community structures were investigated in transgenic Bt cultivars, Bollgard(B) and Chinese cotton 30 (CC30), and common cultivars, control (C) and no control (NC) cotton field in North China in 1998. The results showed that compared with common cultivars, the species richness and the number of total individual of arthropod community in transgenic Bt cultivars field were reduced 2.4-16.3% and 71.0-78.3% respectively, in which dominant species in phytophagous subcommunity varied. The number of individual of predatory and parastic subcommunity were all increased. The similarity coefficient between CC30 and NC was 0.8243, B and NC 0.7320, B and C 0.3380, C and NC 0.3128, CC30 and C 0.2665. The order of diversity and evenness value of these were CC30 (2.3712 and 0.6428), NC (2.3654 and 0.6251), B (2.1364 and 0.5791), and C (1.0877 and 0.2949), their dominant value was 0.8726 (C), 0.3528(B), 0.1178(NC) and 0.1048 (CC30) respectively. It was concluded that different integrated pest management (IPM) strategy should be implemented in transgenic Bt cotton instead of common variety cotton field.

Animals↗

PubMed2001

[3-D angiography in diagnosis and treatment of intracranial aneurysm].

OBJECTIVE: To summarize the results of initial application of three-dimensional angiography (3D-Angio) in diagnosis and treatment of intracranial aneurysms. METHODS: From August 1999 to January 2001, standard digital subtraction angiography (two-dimensional angiography, 2D-Angio) and 3D-Angio(obtained by reconstruction of rotational angiography) were performed in 65 patients with confirmed or suspected aneurysms. RESULTS: Sixty-six aneurysms were found in 60 patients and nothing was found in 5. Of 66 the aneurysms (60 cases), 46 (43 cases) were treated by intrasaccule embolizotion with coils, 3 (3 cases) by occluding the parent artery with detachable balloon, 10 (10 cases) by surgery, and 1 (1 case) by combination of extracranial-intracranial bypass and balloon occlusion of parent artery. Six (3 cases) were not treated. Two aneurysms that could not be detected by 2D-Angio were diagnosed by 3D-Angio. Three aneurysms that were difficult or dangerous to embolize by 2D-Angio were embolized successfully with the help of 3D-Angio. Three aneurysms seemed to be embolized on 2D-Angio were proved impossible to be embolized on 3D-Angio. Of the 46 aneurysms embolized intrasaccularly, 38(82.6%) were completely embolized on 2D-Angio. In the 38, 8 had residual aneurysm on 3D-Angio. CONCLUSION: More accurate diagnosis and secure treatment of intracranial aneurysm can be reached by 3D-Angio.

Adolescent↗

PubMed2001

[Study on anti-HBV effects by antisense oligodeoxynucleotides in vitro].

OBJECTIVE: To study the inhibition effect of anti-HIV oligodeoxy-nucleotides on HBV X gene. METHODS: Three antisense phosphorothioate oligodeoxy-nucleotides(AsON) complementary to the initiator of X, DR2, EN II respectively, were synthesized and tested for their anti-HBV activity on HepG2.2.15 cells with ELISA methods. RESULTS: When the best effect concentration of AsON was 10 mumol/L, the inhibition rates on HBsAg of three AsON were 57%, 60% and 52% respectively, and on HBeAg were 56%, 45% and 56% respectively. There were two inhibition peaks at different times. There was no inhibition effect treated by random control (< 12%). Using the 3-(4,5-dimethythiazol-xyl)-2,5-diphnyl tetrazolium bromide method, there was no cytotoxicity at 40 mumol/L of AsON. CONCLUSION: AsONs on three key region of X gene were effective drugs to inhibit the expression of HBV.

Antiviral Agents↗

PubMed2001

[An experimental study on the delayed resuscitation of dogs with burn shock].

OBJECTIVE: To explore the effects of delayed resuscitation on burn shock with ringer's solution. METHODS: Twelve mongrel dogs were randomly divided into control (S, n = 6) and treatment (LR, n = 6) groups. The dogs in LR group were inflicted by 35% TBSA III degree burn and were resuscitated with Lactate Ringer's solution. Urine output in amount of 1 ml.kg-1.h-1, and cardiac output at level of 70% approximately 80% of pre-burn level were referred for the modulation of the speed and amount of fluid infusion. The postburn changes of volumetric load, mean arterial pressure (MAP), LVSP +/- dp/dtmax, CI, DO2 and VO2 during the first 24 hours of resuscitation were observed. RESULTS: The infusion amount of LR solution was 8.87 +/- 1.02 ml/kg per 1% TBSA during the first 24 hours of resuscitation, which was 1.2 times more than that with Parkland formula. Furthermore, the infusion fluid amount within the first 4 hours of resuscitation was (3.63 +/- 0.99) ml.kg(-1).1% TBSA-1, which was 41% of total amount within the first 24 hours. MAP, LVSP, +/- dp/dtmax, CI, DO2 and VO2 reached or approached the levels in S group within 2 hours of resuscitation. CONCLUSION: The infusion amount of Lactate Ringer's solution needed in delayed resuscitation was larger than that in early resuscitation. And the indices of hemodynamics and myocardial mechanics were improved obviously within 2 hours of resuscitation.

Animals↗

PubMed2001

Activation of NF-kappa B in bronchial epithelial cells from children with asthma.

OBJECTIVES: To determine whether nuclear factor-kappa B (NF-kappa B) is activated in epithelial cells from children with asthma and to understand the role of NF-kappa B in airway inflammation in asthma. METHODS: Bronchial mucosa specimens were obtained from 9 children with asthma and 6 control subjects. NF-kappa B expression in epithelial cells were detected by immunohistochemical examination, and NF-kappa B-DNA binding was measured by electrophoretic mobility shift assay (EMSA). RESULTS: Nuclear expression of NF-kappa B in epithelial cells was observed in the 9 asthmatic children. NF-kappa B-DNA binding was found in 4 asthmatic children (EMSA was performed in 6 asthmatic children). In contrast, both nuclear expression and NF-kappa B-DNA binding were absent in the 6 control subjects. CONCLUSION: These results indicated that NF-kappa B is activated in epithelial cells from asthmatic children and the NF-kappa B activation may be the basis for the increased expression of many inflammatory genes and for airway inflammation in asthma.

Asthma↗

PubMed2001

[Suppression subtractive hybridization in the cloning of gene fragments in relation to lung cancer metastasis].

OBJECTIVE: In order to provide important information about early diagnosis and treatment of tumor metastasis, a study on the biological regulation of metastasis at the molecular level was carried out by isolating and identifying human metastatic suppressor gene or related DNA sequences from a pair of cell clones with different metastatic phenotypes. METHODS: Suppression subtractive hybridization technique (SSH), gene cloning and analysis by bioinformatics were applied to this study. Two cell clones of pulmonary giant cell carcinoma originating from the same patient were used. The PLA-801C cell clone which shows lower metastatic potentiality was used as tester and the PLA-801D as a driver. RESULTS: Five cDNA clones so obtained were expressed on much higher levels in the poorly metastatic cancer cell clone than the highly metastatic one. Homology analysis of all five cDNA fragments by BLASTN through GenBank showed high homology with the known human genes. CONCLUSION: Through using SSH, we have identified five cDNA fragments which are expressed at much higher levels in the poorly metastatic cancer cell clone than the highly metastatic variety. Therefore, it is supposed that they might play an important role in the suppression of metastatic tumor cells and may very well have potential application in the diagnosis and treatment of metastasis.

Base Sequence↗

PubMed2001

[Estimation of insulin secretion rate in multiple sampled intravenous glucose tolerance test].

OBJECTIVE: To measure and calculate insulin secretion rate(ISR) in multiple sampled intravenous glucose tolerance test (FSIVGTT) according to the two compartment model and standard parameters of the kinetics of connecting peptide (C-P) in vivo. METHODS: 15 subjects with normal glucose tolerance and 11 type 2 diabetic patients took part in the study. Oral glucose tolerance test (OGTT) and FSIVGTT were performed. Glucose concentrations were measured by hexokinase method. Insulin (INS) and C-P concentrations were measured by radioimmunoassay. A computer procedure devised by our laboratory was used to calculate the value of ISR at each time point. RESULTS: In the control group, serum INS and C-P concentrations reached the peak at 4 min, the second peak was not obvious. In type 2 diabetes, only 5 subjects had a small peak within 4 min, two curves reached its peak between 60 and 80 min. In the control group, ISR reached its peak 2 min after injection of glucose, that was earlier than INS and C-P curves in time sequence (P = 0.000), the second obvious peak was shown at 22 min. In type 2 diabetes, an obvious but small peak of ISR was shown at 2 min and all the patients had this peak. CONCLUSIONS: It is necessary to take the process of metabolic clearance of INS and C-P into consideration, when blood concentration of INS and C-P were used as indexes to evaluate the secretion function of beta-cells. The ISR profile is more sensitive for investigation of the second phase of insulin secretion in the control group and the first phase in type 2 diabetes group.

Blood Glucose↗

PubMed2001

[The impact of early diagnosis and thrombolytic-anticoagulant therapies on outcome of pulmonary embolism].

OBJECTIVE: To investigate the effect of early diagnosis and thrombolytic followed by anticoagulant therapy in pulmonary embolism (PE). METHODS: 46 patients diagnosed as PE were retrospectively analyzed. All the patients were treated with thrombolytic followed by anticoagulant therapy. Therapeutic effect was compared between two groups of patients with symptoms more or less than two weeks before establishment of diagnosis. RESULT: 36 patients were documented as PE by lung scan, 13 of 46 patients (28.3%) were misdiagnosed as other heart or lung diseases. All the patients had accompanying diseases, including leg deep vein thrombosis (DVT) (33/46, 71.7%) heart or lung diseases other than PE(23/46, 50%), and history of surgery (6/46, 3%). 93.1% of the patients with clinical history less than 2 weeks showed improvement, whereas only 52.9% of those with clinical history exceeding 2 weeks improved. There was significant difference between them. CONCLUSION: In order to diagnose PE early, we should pay more attention to the risk factors of PE, especially DVT. The success of thrombolysis appears to depend on the interval between the onset of symptoms and start of thrombolytic therapy. Patients with clinical symptoms less than 2 weeks show better improvement.

Adult↗

PubMed2001

[Study on active constituents of traditional Chinese medicine reversing multidrug resistance of tumor cells in vitro].

OBJECTIVE: To screen drugs reversing multidrug resistance of tumor cells from active constituents of traditional Chinese medicine and to study the reversal action. METHODS: The kill effects of the drugs on tumor cell lines in vitro were determined with MTT method. The Jin's formula was used to analyse the effect of drug combination. RESULTS: 5 micrograms/ml rhynchophylline, 2 micrograms/ml jatrorrhizine and 1.25 micrograms/ml indirulin could reverse multidrug resistance for vincristine on KBv200 cell line by 16.8, 5.1 and 4 fold respectively. 1.56-12.5 micrograms/ml curcumine combining with vincristine could sensitize antitumor effect both on KB and KBv200 cell lines. CONCLUSION: All rhynchophylline, jatrorrhizine and indirulin could reverse multidrug resistance for vincristine on KBv200 cell line. Curcumine combinating vincristine could sensitize antitumor effect both on kB and kBv200 cell lines.

Antineoplastic Agents, Phytogenic↗

PubMed2001

[Effect of treatment with continuous positive airway pressure on nocturnal polyuria in patients with obstructive sleep apnea syndrome].

OBJECTIVE: To investigate the effect of treatment with continuous positive airway pressure (CPAP) on nocturnal polyuria in patients with obstructive sleep apnea syndrome (OSAS). METHODS: 15 patients with obstructive sleep apnea syndrome were included. The number of nocturia, the nocturia output, the osmotic pressure of nocturia and the nocturia excretion of Na(+) were recorded. Plasma levels of atrial natriuretic peptide (ANP) in night were measured in 8 patients. After treatment with CPAP, all the criteria were repeated. RESULTS: (1) The number of nocturia decreased significantly after treatment with CPAP (P < 0.01); (2) The difference between nocturia output pre-and post treatment was significant (P < 0.01); (3) The osmotic pressure of nocturia rose from (381 +/- 96) mmol/L to (570 +/- 169) mmol/L (P < 0.05); (4) The nocturia excretion of Na(+) dropped from (1.16 +/- 0.35) mmol/h to (0.63 +/- 0.13) mmol/h (P < 0.01); (5) Plasma levels of ANP in night decreased from (146 +/- 14) ng/L to (106 +/- 10) ng/L (P < 0.01); (6) After treatment with CPAP, the reduction of ANP is correlated with the reduction of the nocturia output, the addition of the osmotic pressure of nocturia and the reduction of the nocturia excretion of Na(+). The correlation coefficients were 0.82, 0.84, 0.81 respectively. CONCLUSION: Treatment with CPAP can reduce the number of nocturia, the nocturia output and the nocturia excretion of Na(+), increase the osmotic pressure of nocturia. The changes probably relate to the reduction of plasma level of ANP.

Adult↗