Biomedical subjects

Qing Lu

Publications and source records attributed to Qing Lu.

At least 55 records · Page 3Linked to original sources

PubMed2004

Angiotensin receptor gene expression in candesartan mediated neuroprotection.

Male Wistar rats were treated with an angiotensin AT1 receptor antagonist, candesartan cilexetil (TCV-116, 1 mg/kg/day) over a 4-week period. Systolic blood pressure was significantly reduced by 14% after 1 week and remained stable for the next 3 weeks compared with controls. Up-regulation of AT2, but not AT1, receptor gene expression by 3.4-fold and 5.0-fold was observed 1 and 4 weeks after treatment. Middle cerebral artery occlusion caused significantly reduced infarct volumes in TCV-116-treated rats, by about 30% when compared with control rats. Neurological scores were also improved in treated rats. These results suggest that the neuroprotective effects of TCV-116 may be mediated through AT1 receptor antagonism and AT2 receptor up-regulation.

Analysis of Variance↗

PubMed2004

Striatin assembles a membrane signaling complex necessary for rapid, nongenomic activation of endothelial NO synthase by estrogen receptor alpha.

Steroid hormone receptors (SHRs) are ligand-activated transcription factors that regulate gene expression. SHRs also mediate rapid, nongenomic cellular activation by steroids. In vascular endothelial cells, the SHR for estrogen, estrogen receptor (ER) alpha, is targeted by unknown mechanisms to a functional signaling module in membrane caveolae that enables estrogen to rapidly activate the mitogen-activated protein kinase and phosphatidylinositol 3-Akt kinase pathways, and endothelial NO synthase (eNOS). Here we identify the 110-kDa caveolin-binding protein striatin as the molecular anchor that localizes ERalpha to the membrane and organizes the ERalpha-eNOS membrane signaling complex. Striatin directly binds to amino acids 183-253 of ERalpha, targets ERalpha to the cell membrane, and serves as a scaffold for the formation of an ERalpha-Galphai complex. Disruption of complex formation between ERalpha and striatin blocks estrogen-induced rapid activation mitogen-activated protein kinase, Akt kinase, and eNOS, but has no effect on ER-dependent regulation of an estrogen response element-driven reporter plasmid. These findings identify striatin as a molecular scaffold required for rapid, nongenomic estrogen-mediated activation of downstream signaling pathways. Furthermore, by demonstrating independent regulation of nongenomic vs. genomic ER-dependent signaling, these findings provide conceptual support for the potential development of "pathway-specific" selective ER modulators.

Calmodulin-Binding Proteins↗

PubMed2004

Potential involvement of leptin in carcinogenesis of hepatocellular carcinoma.

AIM: To investigate the potential involvement of leptin in carcinogenesis of hepatocellular carcinoma (HCC) and to elucidate the etiology, carcinogenesis and progress of HCC. METHODS: Expressions of Ob gene product, leptin and its receptor, Ob-R were investigated in 36 cases of HCC specimens and corresponding adjacent non-tumorous liver tissues with immunohistochemical staining. The effect of leptin on proliferation of Chang liver cell line and liver cancer cell line SMMC-7721 was studied with cell proliferation assay (MTT). RESULTS: Leptin expression was detected in 36 cases of adjacent non-tumorous liver tissues (36/36, 100%) with moderate (++) to strong (+++) intensity; and in 72.22%(26/36) of HCC with weaker (+) intensity (P<0.05). Thirty of 36 (83.33%) cases of adjacent non-tumorous liver tissues were positive for Ob-R, with moderate (++) to strong (+++) intensity. In HCC, 11/36 (30.56%) cases were positive, with weak (+) intensity (P<0.05). In cell proliferation assay, leptin inhibited the proliferation of Chang liver cells. The cell survival rate was 10-13% lower than that of the untreated cells (P>0.05). Leptin had little effect on the proliferation of liver cancer cells (P>0.05). CONCLUSION: High level expression and decreased or absent expression of leptin and its receptor in adjacent non-tumorous liver cells and HCC cells, inhibitory effect of leptin on the proliferation of normal Chang liver cells and no effect of leptin on proliferation of liver cancer cells, may provide new insights into the carcinogenesis and progression of human HCC. It could be assumed that leptin acting as an inhibitor and/or promoter, is involved in the process of carcinogenesis and progress of human HCC.

Adult↗

PubMed2004

A multilocus likelihood approach to joint modeling of linkage, parental diplotype and gene order in a full-sib family.

BACKGROUND: Unlike a pedigree initiated with two inbred lines, a full-sib family derived from two outbred parents frequently has many different segregation types of markers whose linkage phases are not known prior to linkage analysis. RESULTS: We formulate a general model of simultaneously estimating linkage, parental diplotype and gene order through multi-point analysis in a full-sib family. Our model is based on a multinomial mixture model taking into account different diplotypes and gene orders, weighted by their corresponding occurring probabilities. The EM algorithm is implemented to provide the maximum likelihood estimates of the linkage, parental diplotype and gene order over any type of markers. CONCLUSIONS: Through simulation studies, this model is found to be more computationally efficient compared with existing models for linkage mapping. We discuss the extension of the model and its implications for genome mapping in outcrossing species.

Alleles↗

PubMed2004

Echocardiographic diagnosis of total anomalous pulmonary venous connection.

To investigate the value of echocardiography in the diagnosis of total anomalous pulmonary venous connection (TAPVC), 16 patients in our hospital were diagnosed to have TAPVC by echocardiography from year 1994 to 2001. In 11 cases the results of echocardiography were compared to those of surgery. Each patient was examined by using a combination of precordial, suprasternal and subcostal windows to visualize all the pulmonary veins and their drainage sites, common pulmonary venous trunk, and other associated abnormalities. Of the 16 cases, the drainage sites were as follow: supracardiac in 10, via vertical vein in 9, directly to superior vena cava in 1; cardiac in 5, via coronary sinus in 2, directly to right atrium in 3. Diagnoses were correctly made in all the 11 cases as confirmed by surgery. Echocardiography can also assess pulmonary arterial pressure and detect other associated abnormalities. It is concluded that echocardiography is the preferred examination method in the diagnosis of TAPVC before surgery. With careful examination using multiple windows and sections, TAPVC can be accurately diagnosed by echocardiography.

Adolescent↗

PubMed2004

Real-time 3-dimensional echocardiography in assessing atrial and ventricular septal defects: an echocardiographic-surgical correlative study.

OBJECTIVE: The aim of this study is to explore the feasibility and the value of real-time 3-dimensional echocardiography (RT3DE) in quantitative evaluation of the size of atrial septal defect (ASD) and ventricular septal defect (VSD) and to correlate with the surgical findings. METHODS: Thirty eight patients with ASD and/or VSD were examined with RT3DE. Three-dimensional image data-base was post-processed using 3D work-station. The results were compared with the results measured by 2-dimensional echocardiography and surgical findings. RESULTS: RT3DE produced novel views of congenital septal defects and improved quantification of the size of the defect. The sizes obtained from 3DE have better correlation with surgical findings than diameter measured by 2-dimensional echocardiography (r = 0.69 vs r = 0.92). CONCLUSIONS: RT3DE offers additional special information in congenital heart disease without extending examining time, permits quantitative recording of septal defect dynamics, and enhances the understanding of complex cardiac anatomy and elucidation of the disease mechanism. It is a potentially valuable clinical tool for diagnosing and managing patients with congenital heart disease.

Adolescent↗

PubMed2004

Using overall allele-sharing to detect the presence of large-scale data errors and parameter misspecification in sib-pair linkage studies.

Data errors and marker allele frequency misspecification can lead to incorrect inference in linkage analysis. Here we demonstrate the effect of each on an allele-sharing statistic in a sample of sib pairs. In the context of relationship testing, we propose a new test that compares the sample genome-wide sib-pair allele sharing to its expectation and show that this test can detect the presence of large-scale data and model errors.

Alleles↗

PubMed2004

[Clinical study of plasma urotensin II in patients with coronary heart disease].

OBJECTIVE: To investigate the changes in plasma urotensin II(U II) expression levels in patients with coronary heart disease (CHD). METHODS: Plasma U II levels in 50 CHD patients with coronary stenosis indicated by coronary angiography and 20 healthy subjects were determined by radio immunoassay. RESULTS: Venous plasma U II levels were significantly lowered in CHD patients in comparison with the healthy subjects (1.61+/-1.02 pg/ml vs 3.70+/-1.30 pg/ml, P=0.000). In the CHD patient group, significantly differences were noted in the U II levels between patients with stable angina (2.62+/-1.20 pg/ml), unstable angina (1.39+/-0.80 pg/ml) and acute myocardial infarction (AMI, 1.04+/-0.45 pg/ml, P=0.004). CHD patients with coronary artery occlusion and those with only coronary stenosis had comparable venous plasma U II levels (1.29+/-1.02 pg/ml vs 1.76+/-1.00 pg/ml, P=0.131), whereas the patients with restenosis after percutaneous transluminal coronary angioplasty (PTCA) had higher U II levels than the other subjects in the CHD patient group (2.28+/-0.94 pg/ml vs 1.40+/-0.96 pg/ml, P=0.008), and the femoral plasma U II levels were significantly elevated after PTCT, increasing from 1.18+/-1.14 pg/ml to a postoperative level of 2.22+/-1.77 pg/ml (P=0.001). CONCLUSION: U II might play a role in the pathophysiological process of CHD and can be involved in the restenosis after angioplasty.

Adult↗

PubMed2004

[Effect of percutaneous intervention on adrenomedullin and tumor necrosis factor in the coronary circulation].

OBJECTIVE: To evaluate the effect of percutaneous intervention (PCI) on coronary circulation levels of adrenomedullin (ADM) and tumor necrosis factor alpha (TNF-alpha) in patients with coronary heart disease (CHD). METHODS: Thirty-three CHD patients underwent percutaneous transluminal coronary angioplasty (PTCA) and stenting (altogether 48 stents were implanted). Blood samples were collected from the coronary sinus and femoral artery at the time points of immediately before and after angioplasty, immediately after PTCA or stenting, 10 min after procedures, respectively. RESULTS: The ADM and TNF-alpha levels in the coronary sinus varied little after coronary angiography, but were elevated markedly following PTCA from the basal levels of 36.3+/-1.3 pg/ml to 28.9+/-1.9 pg/ml (P<0.01) and from 11.10+/-0.46 ng/ml to 8.84+/-0.37 ng/ml (P<0.01), respectively. Further increases of ADM and TNF-alpha levels were detected immediately after stent deployment. ADM recovered to basal levels 10 min after completion of the procedures, while TNF-alpha underwent further increase. Before the procedure, ADM and TNF-alpha levels were higher in the coronary sinus than in the femoral artery (28.9+/-1.9 pg/ml vs 22.6+/-0.8 pg/ml, P<0.01; 8.84+/-0.37 ng/ml vs 7. 56+/-0.23 ng/ml, P<0.01, respectively), and their levels in the femoral artery did not undergo significant changes in response to the operations. CONCLUSION: The coronary circulation levels of ADM and TNF-alpha increase after PTCA and stenting but not after coronary angiography in CHD patients, which might be attributed to injuries by the procedures as well as the mechanical stimulation by the stent.

Adrenomedullin↗

PubMed2003

Isoprenylcysteine carboxyl methyltransferase modulates endothelial monolayer permeability: involvement of RhoA carboxyl methylation.

RhoA and Rac1 regulate formation of stress fibers and intercellular junctions, thus modulating endothelial monolayer permeability. Posttranslational modifications of RhoA and Rac1 regulate enzyme activity and subcellular localization, resulting in altered cellular function. The role of RhoA and Rac1 carboxyl methylation in modulating endothelial monolayer permeability is not known. In this study, we found that inhibition of isoprenylcysteine-O-carboxyl methyltransferase (ICMT) with adenosine plus homocysteine or N-acetyl-S-geranylgeranyl-l-cysteine decreased RhoA carboxyl methylation, RhoA activity, and endothelial monolayer permeability, suggesting that RhoA carboxyl methylation may play a role in the ICMT-modulated monolayer permeability. Similar studies showed no effect of ICMT inhibition on Rac1 carboxyl methylation or localization. Bovine pulmonary artery endothelial cells (PAECs) stably overexpressing ICMT-GFP cDNA were established to determine if increased ICMT expression could alter RhoA or Rac1 carboxyl methylation, activation, and endothelial monolayer permeability. PAECs stably overexpressing ICMT demonstrated increased RhoA carboxyl methylation, membrane-bound RhoA, and RhoA activity. Additionally, PAECs stably overexpressing ICMT had diminished VE-cadherin and beta-catenin at intercellular junctions, with resultant intercellular gap formation, as well as enhanced monolayer permeability. These effects were blunted by adenosine plus homocysteine and by inhibition of RhoA, but not by inhibition of Rac1. These results indicate that ICMT modulates endothelial monolayer permeability by altering RhoA carboxyl methylation and activation, thus changing the organization of intercellular junctions. Therefore, carboxyl methylation of RhoA may modulate endothelial barrier function.

Adenosine↗

PubMed2003

High-density lipoprotein increases the abundance of eNOS protein in human vascular endothelial cells by increasing its half-life.

OBJECTIVES: Given the importance of endothelial nitric oxide synthase (eNOS) in regulating endothelium-dependent vasorelaxation, we investigated the effects of high-density lipoprotein in (HDL) on eNOS protein abundance in cultured human vascular endothelial cells. BACKGROUND: Endothelial dysfunction, characterized by decreased nitric oxide production, is one of the early features in the development of atherosclerosis. We have recently shown in vivo that niacin therapy increases plasma HDL concentration and improves endothelium-dependent vasorelaxation in patients with coronary artery disease. METHODS: Human vascular endothelial cells were cultured in the presence or absence of HDL or apolipoprotein (apo)A-I. The eNOS protein abundance was assessed by immunoblotting, and protein half-life was assessed by pulse-chase techniques. The eNOS messenger ribonucleic acid (mRNA) abundance was measured using real-time quantitative polymerase chain reaction. RESULTS: High density lipoprotein, or apoA-I alone, increased eNOS protein abundance by 3.5 +/- 0.7 and 2.7 +/- 0.5-fold, respectively (p < 0.05 for both). However, neither HDL nor apoA-I increased eNOS mRNA abundance. It was shown that HDL increased eNOS protein half-life up to 3.3 +/- 0.2-fold (p = 0.001). Both HDL and apoA-I activated mitogen-activated protein-kinase and phosphatidylinositol 3-kinase (PI3K) Akt-pathways in human arterial endothelial cells, and inhibition of either of these pathways by specific pharmacologic inhibitors abolished the effect of HDL on eNOS. CONCLUSIONS: We demonstrate that HDL activates both extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt, resulting in enhanced eNOS protein stability and subsequent accumulation of eNOS protein. This posttranslational regulation represents a previously unrecognized mechanism for regulating eNOS.

Apolipoprotein A-I↗

PubMed2003

Acetylation of cAMP-responsive element-binding protein (CREB) by CREB-binding protein enhances CREB-dependent transcription.

The coactivator function of cAMP-responsive element-binding protein (CREB)-binding protein (CBP) is partly caused by its histone acetyltransferase activity. However, it has become increasingly clear that CBP acetylates both histones and non-histone proteins, many of which are transcription factors. Here we investigate the role of CBP acetylase activity in CREB-mediated gene expression. We show that CREB is acetylated within the cell and that in vitro, CREB is acetylated by CBP, but not by another acetylase, p300/CBP-associated factor. The acetylation sites within CREB were mapped to three lysines within the CREB activation domain. Although inhibition of histone deacetylase activity results in an increase of CREB- or CBP-mediated gene expression, mutation of all three putative acetylation sites in the CREB activation domain markedly enhances the ability of CREB to activate a cAMP-responsive element-dependent reporter gene. Furthermore, these CREB lysine mutations do not increase interaction with the CRE or CBP. These data suggest that the transactivation potential of CREB may be modulated through acetylation by CBP. We propose that in addition to its functions as a bridging molecule and histone acetyltransferase, the ability of CBP to acetylate CREB may play a key role in modulating CREB-mediated gene expression.

Acetylation↗

PubMed2003

The extent and distribution of linkage disequilibrium in a multi-hierarchic outbred canine pedigree.

A canine integrated linkage-radiation map has been recently constructed by using microsatellite markers. This map, with a good coverage of the canine genome, allows for a genome-wide search for the extent and distribution of linkage disequilibrium derived from linkage and evolutionary forces. In this study, we genotyped an outbred pedigree between Labrador retriever and Greyhound breeds with a set of microsatellite markers (240) from the canine linkage map. Linkage disequilibrium was measured between all syntenic and nonsyntenic marker pairs. Analysis of syntenic pairs revealed a significant correlation (-0.229, P < 0.001) between linkage disequilibrium and genetic distance (log transformed). Significant linkage disequilibria were observed more frequently between syntenic pairs spaced <40 cM than those paced >40 cM. There is a clear trend for linkage disequilibrium to decline with marker distance. From our results, a genome-wide screen with markers at low to moderate density (1-2 per 10 cM) should take full advantage of linkage disequilibrium for quantitative trait locus mapping in dogs. This study supports the appropriateness of linkage disequilibrium analysis to detect and map quantitative trait loci underlying complex traits in dogs.

Animals↗

PubMed2003

The relationship between aromatase in primary breast tumors and response to treatment with aromatase inhibitors in advanced disease.

Aromatase inhibitors are proving to be more effective than tamoxifen for postmenopausal patients with breast cancer. Estrogen concentrations in the breast are similar in both premenopausal and postmenopausal women, and several fold higher than circulating levels in postmenopausal women. In order to investigate the importance of intratumoral aromatase in stimulating the proliferation of the tumor, we used immunocytochemistry to determine the extent of aromatase expression in relationship to the response of the patient to aromatase inhibitor treatment. The relationship between positive staining for aromatase in the primary tumor and response to treatment with an aromatase inhibitor was investigated in a retrospective study of 102 patients with advanced breast cancer. Immunohistochemical staining using a monoclonal antibody against aromatase was performed on paraffin embedded tumor tissue. Response was evaluated using UICC criteria. Nine out of 13 patients with objective response to treatment stained positive and 49 of 89 patients with stable or progressive disease stained positive. No significant relationship between positive staining and objective response to treatment could be found. When patients with 'clinical benefit' (i.e. objective response plus prolonged stable disease of at least 6 months) were considered, also no relationship could be found. Further analysis of subgroups with positive hormone receptors, treatment with newer generation aromatase inhibitors, single metastatic site, non-visceral metastases and previous treatment only with tamoxifen did not show any relationship. Tumor aromatase expression did not correlate with response of patients with advanced breast cancer to aromatase inhibitor treatment. Most patients had relapsed from other treatments before receiving an aromatase inhibitor. It seems likely that many of these patients had tumors that may have progressed to hormone independence at this stage of the disease. Research in patients who have received treatment with aromatase inhibitors in earlier stages of disease (first line and adjuvant treatment) may provide further information on the relationship between tumor aromatase, steroid receptors and response to inhibitor treatment.

Adult↗

PubMed2003

Micro- and macrocirculatory effects of apheresis in patients with familial hyperlipidemia.

High lipid levels have been shown to coexist with a disturbed vascular endothelial function. Thus, acute lipid lowering could be expected to improve vascular reactivity. Patients with familial hyperlipidemia (FH) have substantial and rapid decreases in lipid levels after low-density lipoprotein apheresis. Thus, an opportunity exists to study acute effects of lipid lowering on vascular reactivity. Flow mediated vasodilation (FMD) is commonly used to assess endothelial function in conduit vessels, whereas vital capillary microscopy during the post-reactive hyperemia (PRH) phase is used to assess response at the microvascular level. It is not known whether endothelial dysfunction is a general phenomenon in all kinds of vessels or if there are differences between micro- and macrovessels. In the present study, we were not able to demonstrate an improved vascular response after acute lipid lowering in FH patients. This was true both in the microcirculation (PRH) and in the conduit vessels (FMD). However, the two methods gave concordant results, demonstrating disturbed vascular reactivity in the patients as compared with healthy subjects. We have found no previous report with parallel assessments at the microcirculatory and macrocirculatory levels.

Adult↗

PubMed2003

Isoprenylcysteine carboxyl methyltransferase activity modulates endothelial cell apoptosis.

Extracellular ATP, adenosine (Ado), and adenosine plus homocysteine (Ado/HC) cause apoptosis of cultured pulmonary artery endothelial cells through the enhanced formation of intracellular S-adenosylhomocysteine and disruption of focal adhesion complexes. Because an increased intracellular ratio of S-adenosylhomocysteine/S-adenosylmethionine favors inhibition of methylation, we hypothesized that Ado/HC might act by inhibition of isoprenylcysteine-O-carboxyl methyltransferase (ICMT). We found that N-acetyl-S-geranylgeranyl-L-cysteine (AGGC) and N-acetyl-S-farnesyl-L-cysteine (AFC), which inhibit ICMT by competing with endogenous substrates for methylation, caused apoptosis. Transient overexpression of ICMT inhibited apoptosis caused by Ado/HC, UV light exposure, or tumor necrosis factor-alpha. Because the small GTPase, Ras, is a substrate for ICMT and may modulate apoptosis, we also hypothesized that inhibition of ICMT with Ado/HC or AGGC might cause endothelial apoptosis by altering Ras activation. We found that ICMT inhibition decreased Ras methylation and activity and the activation of the downstream signaling molecules Akt, ERK-1, and ERK-2. Furthermore, overexpression of wild-type or dominant active H-Ras blocked Ado/HC-induced apoptosis. These findings suggest that inhibition of ICMT causes endothelial cell apoptosis by attenuation of Ras GTPase methylation and activation and its downstream antiapoptotic signaling pathway.

Acetylcysteine↗

PubMed2003

[Clinical study of changes of urotensin II in patients with congestive heart failure].

OBJECTIVE: To investigate the changes of plasma urotensinII (UII) levels in patients with congestive heart failure (CHF) of different severities and their clinical implications. METHODS: Plasma UII was determined by radioimmunoassay in 45 patients with CHF and 20 healthies control subjects. In all the subjects, the left ventricular fraction (LVEF) and the ratio of E/A were measured by echocardiography. RESULTS: The plasma UII level was significantly lowered in CHF patients in comparison with that in control subjects (1.41+/-1.09 pg/ml vs 4.35+/-1.22 pg/ml, P=0.000). A significant correlation of plasma UII level with LVEF (r=0.540, P=0.000) and the E/A ratio was observed (r=0.539, P=0.000), and the severity of CHF was shown to be inversely correlated with plasma UII levels in the patients (r=-0.656, P=0.000), which was elevated after treatment. CONCLUSION: UII might play a role in the pathophysiological process of CHF, and its plasma level may serve as an indicator of the severity of CHF.

Adult↗

PubMed2003

[Association of platelet endothelial cell adhesion molecule-1 gene polymorphism with coronary heart disease].

OBJECTIVE: To investigate the association of Leu125Val and Ser563Asn polymorphism of the gene encoding platelet endothelial cell adhesion molecule-1(PECAM-1) with coronary heart disease. METHODS: This study included 156 patients with the diagnoses of coronary heart disease (CHD) and coronary lesions derived from electrocardiography, myocardial enzyme analysis and coronary angiography as the CHD group, and another 75 in-patients admitted within the same period who showed no signs of CHD in the above examinations constituted the control group. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was employed to examine the missense polymorphism of PECAM-1gene in the position of Leu125Val and Ser563Asn. RESULTS: There were significant differences between CHD and control group in terms of the allele frequencies and genotype distributions of PECAM-1 gene, and the differences were especially conspicuous in the allele frequencies of 125Val and 563Asn (P<0.05) and genotype distributions of 125Val/Val and 563Asn/Asn. CONCLUSION: PECAM-1 gene polymorphism 1 may be a genetic risk factor for coronary heart disease.

Coronary Disease↗