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Qingyu Wu

Publications and source records attributed to Qingyu Wu.

At least 37 records · Page 2Linked to original sources
PubMed2004

The ManR specifically binds to the promoter of a Nramp transporter gene in Anabaena sp. PCC 7120: a novel regulatory DNA motif in cyanobacteria.

The Anabaena sp. PCC 7120 ManR and a homologous protein of MntH were identified by BLAST search. Recombinant ManR protein was overexpressed in Escherichia coli and purified by an immobilized metal (Ni) affinity chromatography. Electrophoretic mobility shift assays revealed that ManR specifically bound to the promoter region of the mntH gene. Site-directed mutagenesis experiments demonstrated that the specific recognition site for ManR is TATGAAAAGAATATGAGAA, which is composed of two direct repeats of the consensus sequence (T/A)ATGA(G/A)A(A/G). This is a novel regulatory DNA motif in cyanobacteria, indicating that the expression of mntH was regulated by a two-component Mn(2+)-Sensing System containing ManR in Anabaena sp. PCC 7120. To date, this specific pathway of regulating mntH expression has only been found in cyanobacteria.

Amino Acid Sequence↗
PubMed2004

A new procedure for Ebstein's anomaly.

BACKGROUND: A new procedure for correction of Ebstein's anomaly that restores to near normal the anatomic and physiologic function of the tricuspid valve and the right ventricle is reported. METHODS: Between December 1997 and September 2002, 34 consecutive patients with Ebstein's anomaly underwent this new procedure. There were 13 male and 21 female patients aged 9 months to 48 years (mean, 17 years). Tricuspid incompetence was moderate in 12 patients and severe in 22. Our repair technique is as follows: the displaced posterior leaflet with some chordae tendineae and corresponding papillary muscle are detached from the annulus and ventricular wall, respectively. The leaflet is then reattached to the native posterior annulus with reimplantation of the papillary muscle. The displaced septal leaflet is treated in the same manner. Most of the atrialized portion of the ventricular wall is excised; the tricuspid annulus is plicated. In 8 of the patients the septal leaflet was severely hypoplastic and necessitated creation of a new leaflet using autologous pericardium. RESULTS: All patients survived and recovered uneventfully. Postoperative echocardiography showed that tricuspid incompetence disappeared in 29 patients and was mild in 5. Right ventricular size decreased significantly with complete disappearance of the atrialized segment. Follow-up of patients ranged from 1 to 55 months (mean, 25 months), with 9 patients having more than 3 years of follow-up. They are doing well and their exercise tolerance improved to normal. CONCLUSIONS: This new procedure anatomically corrects Ebstein's anomaly with the satisfactory early and midterm results.

Adolescent↗
PubMed2004

Cyanobacterial bloom control by ultrasonic irradiation at 20 kHz and 1.7 MHz.

Ultrasonic irradiations at high frequency of 1.7 MHz and low frequency of 20 kHz were tested to prevent cyanobacteria Spirulina platensis from bloom. The inhibition effectiveness at 1.7 MHz was much greater than that at 20 kHz. The cyanobacteria biomass was reduced by 63% after 5 min ultrasonic irradiation at 1.7 MHz, whereas three days were needed for the tested cyanobacteria to recover its original density. However, longer exposure time did not significantly enhance the inhibition. It was observed after ultrasonic irradiation that the gas vesicles in cells collapsed, which may result in cyanobacterial precipitation and photosynthetic inhibition. The concentration of chlorophyll a (Chla) was reduced and its biosynthesis was delayed in a 4-day continuous culture. The fluorescence spectra at 77K of phycobilisome (PBS) and absorption spectra of intact cells in vivo showed that light energy transfer in PBS was inhibited and phycocyanin (PC) was damaged much more acutely compared with Chla. These results indicated that 5 min ultrasonic irradiation at 1.7 MHz every third day might be an effective and economic operation mode for practical application.

Bacterial Proteins↗
PubMed2004

P-selectin-targeting of the fibrin selective thrombolytic Desmodus rotundus salivary plasminogen activator alpha1.

During thrombosis, P-selectin is expressed on the surface of activated endothelial cells and platelets. We hypothesized that targeting a plasminogen activator (PA) to P-selectin would enhance local thrombolysis and reduce bleeding risk. Previously, a urokinase (uPA)/anti-P-selectin antibody (HuSZ51) fusion protein was shown to increase fibrinolysis in a hamster pulmonary embolism model. To explore the therapeutic potential of this targeting strategy, we fused the fibrin-selective Desmodus rotundus salivary PA alpha1 (dsPA alpha 1) to HuSZ51 and compared the fibrinolytic activity of P-selectin-targeted dsPA alpha 1 (HuSZ51-dsPA alpha 1) to unmodified dsPA alpha 1 in vitro and in vivo. HuSZ51-dsPA alpha 1 and dsPA alpha 1 were expressed in CHO cells and purified to homogeneity by affinity chromatography. HuSZ51-dsPA alpha 1 bound to thrombin-activated human and dog platelets with comparable affinities to that of parental antibody SZ51. The fusion protein retained the catalytic activities of dsPA alpha 1 in chromogenic and clot lysis assays, indicating that dsPA alpha 1 is fully functional when fused to HuSZ51. Compared to dsPA alpha 1, HuSZ51-dsPA alpha 1 had similar thrombolytic efficacy in a rat pulmonary embolism model and anti-thrombotic potency in a dog model of femoral artery thrombosis. However, HuSZ51-dsPA alpha 1 was less effective in lysis of preexisting arterial thrombi in the dog model. The reduced arterial thrombolysis was not due to the pharmacokinetic properties of HuSZ51-dsPA alpha 1 because antigen level and amidolytic activity were higher in plasma from HuSZ51-dsPA alpha 1-treated groups than corresponding dsPA alpha 1-treated groups. These data indicate that the thrombolytic efficacy of HuSZ51-dsPA alpha 1 varied dependent on the physical composition of thrombi. The lack of stimulation by fibrin in arterial thrombi may contribute to the attenuated thrombolytic efficacy of HuSZ51-dsPA alpha 1 in the dog model.

Animals↗
PubMed2003

Corin-mediated processing of pro-atrial natriuretic peptide in human small cell lung cancer cells.

Corin is a recently discovered pro-atrial natriuretic peptide (ANP) convertase that is abundantly expressed in the heart. ANP is a cardiac hormone but can be secreted ectopically by certain cancers including small cell lung cancer (SCLC). In this study, we examined the role of corin in ANP production by SCLC cells. Reverse transcription-PCR detected corin mRNA expression in all nine SCLC cell lines examined and ANP mRNA expression in seven of the nine cell lines. In contrast, arginine vasopressin mRNA was detected in only five of the nine SCLC cell lines studied. Corin-expressing SCLC cells were capable of converting recombinant human pro-ANP to biologically active ANP, as determined by Western analysis and a cyclic GMP assay. Transfection of small interfering RNA duplexes directed against the corin gene completely blocked the processing of pro-ANP in the SCLC cells. Our results show that corin functions as a pro-ANP convertase in SCLC cells. We also suggest that the expression of corin may contribute to the pathogenesis of the syndrome of inappropriate secretion of antidiuretic hormone associated with certain cancers.

Arginine Vasopressin↗
PubMed2003

Functional analysis of the transmembrane domain and activation cleavage of human corin: design and characterization of a soluble corin.

Corin is a cardiac transmembrane serine protease. In cell-based studies, corin converted pro-atrial natriuretic peptide (pro-ANP) to mature ANP, suggesting that corin is potentially the pro-ANP convertase. In this study, we evaluated the importance of the transmembrane domain and activation cleavage in human corin. We showed that a soluble corin that consists of only the extracellular domain was capable of processing recombinant human pro-ANP in cell-based assays. In contrast, a mutation at the conserved activation cleavage site, R801A, abolished the function of corin, demonstrating that the activation cleavage is essential for corin activity. These results allowed us to design, express, and purify a mutant soluble corin, EKsolCorin, that contains an enterokinase recognition sequence at the activation cleavage site. Purified EKsolCorin was activated by enterokinase in a dose-dependent manner. Activated EK-solCorin had hydrolytic activity toward peptide substrates with a preference for Arg and Lys residues in the P-1 position. This activity of EKsolCorin was inhibited by trypsin-like serine protease inhibitors but not inhibitors of chymotrypsin-like, cysteine-, or metallo-proteases. In pro-ANP processing assays, purified active EKsolCorin converted recombinant human pro-ANP to biologically active ANP in a highly sequence-specific manner. The pro-ANP processing activity of EKsolCorin was not inhibited by human plasma. Together, our data indicate that the transmembrane domain is not necessary for the biological activity of corin but may be a mechanism to localize corin at specific sites, whereas the proteolytic cleavage at the activation site is an essential step in controlling the activity of corin.

Atrial Natriuretic Factor↗
PubMed2003

Furin-mediated processing of Pro-C-type natriuretic peptide.

C-type natriuretic peptide (CNP) is a member of the natriuretic peptide family that is involved in a variety of homeostatic processes. Here we characterize the processing essential for the conversion of the precursor, human pro-CNP, to the biologically active hormone. In human embryonic kidney 293 and chondrosarcoma SW 1353 cells, recombinant pro-CNP was converted into a mature peptide intracellularly as detected by Western analysis. Expression of recombinant human corin, a proatrial natriuretic peptide convertase, did not enhance the processing of pro-CNP in these cells. The processing of pro-CNP was inhibited in the presence of an inhibitor of the endoprotease furin but was not affected by inhibitors of matrix metalloproteinases and tumor necrosis factor-alpha convertase. In furin-deficient human colon adenocarcinoma LoVo cells, no conversion of recombinant pro-CNP to CNP was detected. Expression of recombinant human furin in LoVo cells restored the ability of these cells to process pro-CNP. Furthermore, incubation of purified recombinant human furin with LoVo cell lysate containing pro-CNP led to the conversion of the precursor to a mature peptide. The furin-processed CNP was shown to be biologically active in a cell-based cGMP assay. These results demonstrate that furin is a critical enzyme for the processing of human pro-CNP.

Blotting, Western↗
PubMed2003

Sucrose accumulation in salt-stressed cells of agp gene deletion-mutant in cyanobacterium Synechocystis sp PCC 6803.

The agp gene encoding the ADP-glucose pyrophosphorylase is involved in cyanobacterial glycogen synthesis and glucosylglycerol formation. By in vitro DNA recombination technology, a mutant with partial deletion of agp gene in the cyanobacterium Synechocystis sp. PCC 6803 was constructed. This mutant could not synthesize glycogen or the osmoprotective substance glucosylglycerol. In the mutant cells grown in the medium containing 0.9 M NaCl for 96 h, no glucosylglycerol was detected and the total amount of sucrose was 29 times of that of in wild-type cells. Furthermore, the agp deletion mutant could tolerate up to 0.9 M salt concentration. Our results suggest that sucrose might act as a similar potent osmoprotectant as glucosylglycerol in cyanobacterium Synechocystis sp. PCC 6803.

Acclimatization↗
PubMed2003

Lipopolysaccharide attenuates thrombolysis in batroxobin-induced lung vasculature fibrin deposition but not in ferrous chloride-induced carotid artery thrombus in rats: role of endogenous PAI-1.

In this study, we investigated if elevation of endogenous plasminogen activator inhibitor type 1 (PAI-1) by lipopolysaccharide (LPS) can retard thrombolysis in both a rat model of lung vasculature fibrin deposition and a platelet-rich thrombus model induced by endothelial injury. By 3 h following an intravenous bolus injection of 0.5 mg/kg LPS, the plasma PAI-1 level had increased to approximately 8 ng/ml. 125I-labeled fibrinogen was injected intravenously followed by an injection of batroxobin. Batroxobin converts fibrinogen into insoluble fibrin, which was then deposited in the lungs within 5 min, followed by spontaneous fibrinolysis that completely cleared fibrin deposition in the lungs by 30 min. In rats pre-treated with LPS, spontaneous fibrinolysis was significantly retarded. In the endothelial injury model, topical application of FeCl2 on the carotid artery induced an occlusive platelet-rich thrombus, which was not sensitive to endogenous thrombolysis. Exogenous tissue-type plasminogen activator (tPA) was required to recanalize the occlusive thrombus in a dose-dependent manner. Pre-treatment with LPS did not alter the dose-response curve of exogenous tPA-induced thrombolysis. These data indicate that batroxobin-induced lung vasculature fibrin deposition in rats, unlike the FeCl2 model, is sensitive to the impact of endogenous PAI-1 on fibrinolysis.

Animals↗
PubMed2003

Modified Rastelli procedure for double outlet right ventricle with left-malposition of the great arteries: report of 9 cases.

BACKGROUND: Double outlet right ventricle with L-malposition of the great arteries is a rare type of double outlet right ventricle. This article reviews our experience in treating this disease surgically. METHODS: Between September 1995 and May 1999, 9 patients with double outlet right ventricle [S, D, L] underwent modified Rastelli procedure at Fu Wai Hospital. In all patients, the two great arteries originated completely from the right ventricle. The malformation was associated with subaortic conus and L-transposition of the great arteries. The ventricular septal defect (VSD) was subpulmonary in 3 patients, and non-committed in 6. All but one patient had either pulmonary valvular stenosis or subpulmonary stenosis. No patient had any type of palliative operation before. A right ventriculotomy was made to repair the VSD with a Dacron or vascular prosthesitic patch, and an intraventricular tunnel was made between the left ventricle and the aorta. The main pulmonary artery was divided and the proximal end was closed. A homograft conduit was implanted between the inlet of the right ventricle and the main pulmonary artery. In the Rastelli procedure, the conduit is usually positioned between the right ventricular outflow tract and the pulmonary artery. RESULTS: All patients survived and recovered uneventfully. Echocardiography demonstrated that all intraventricular tunnels and valved conduits were functioning well. The results were satisfactory. CONCLUSIONS: Modified Rastelli procedure is an optimal method for surgically treating double outlet right ventricle with left-malposition of the great arteries. It can completely correct the right ventricular outflow tract stenosis, and right to left shunt, and avoid injuring the right coronary artery.

Adolescent↗
PubMed2003

Changes in photosynthesis and pigmentation in an agp deletion mutant of the cyanobacterium Synechocystis sp.

The agp gene encoding ADP-glucose pyrophosphorylase is involved in cyanobacterial glycogen synthesis. By in vitro DNA recombination technology, agp deletion mutant (agp-) of cyanobacterium Synechocystis sp. PCC 6803 was constructed. This mutation led to a complete absence of glycogen biosynthesis. As compared with WT (wild type), a 60% decrease in ratio of the c-phycocyanine/chlorophyll a and no significant change in the carotenoid/chlorophyll a were observed in agp- cells. The agp- mutant had 38% less photosynthetic capacity when grown in light over 600 micromol m(-2) s(-1). Under lower light intensity, the final biomass of the mutant strain was only 1.1 times of that of the WT strain under mixotrophic condition after 6 d culture. Under higher light intensity, however, the final biomass of the WT strain under mixotrophic conditions was 3 times that of the mutant strain after 6 d culture and 1.5 times under photoautotrophic conditions. The results indicate that there is a minimum requirement for glycogen synthesis for normal growth and development in cyanobacteria.

Carotenoids↗
PubMed2003

Activated thrombin-activatable fibrinolysis inhibitor attenuates spontaneous fibrinolysis of batroxobin-induced fibrin deposition in rat lungs.

Studies have shown that inhibition of TAFI by small peptides enhances pharmacological effects of tPA in animal models of thrombosis, suggesting that TAFI modulates the fibrinolytic system. In this study, we investigated the effect of activated human TAFI (TAFIa) on endogenous fibrinolysis in a rat model of intravascular fibrin deposition. (125)I-labeled fibrinogen was injected intravenously followed by a bolus injection of batroxobin, a thrombin-like enzyme. Batroxobin cleaved fibrinogen to form insoluble fibrin that was deposited in tissues, including the lungs. This was shown by a decrease of radioactivity in the blood as a result of consumption of (125)I-labeled fibrinogen and an elevation of radioactivity in the lungs 5 min following batrox-obin administration. Endogenous fibrinolysis was detected by a gradual increase in radioactivity in the blood and a decrease in radioactivity in the lungs at 30 min, an indication of radiolabeled fibrin degradation products (FDPs) being released into the circulation from the tissues. Intravenous administration of human TAFIa dose-dependently attenuated the later phase reduction of radioactivity in the lungs. When the dose of TAFIa was 218 micro g/kg, giving a peak plasma level of TAFIa 0.9 +/- 0.05 micro g/ml, the spontaneous fibrinolysis was completely prevented. These results provide direct evidence that an increase in circulating TAFIa impairs endogenous clot lysis in a rat model of fibrin deposition.

Animals↗
PubMed2003

Type II transmembrane serine proteases.

The recent availability of human and mouse genome sequences and expressed sequence tag databases facilitated the identification of a large new family of membrane anchored serine proteases, the type II transmembrane serine proteases or TTSPs. Analyses of human inherited disorders and gene targeting studies in mice have revealed that several members of this new protease family have critical functions in development and health. Preliminary studies also suggest that aberrant expression of type II transmembrane serine proteases may be linked to disease progression. The knowledge gathered thus far of the genetics, physiology, and pathology of this interesting new serine protease family will be reviewed here in brief.

Animals↗
PubMed2003

Comparison of different approaches for pediatric congenital heart diseases.

To compare the clinical results of different surgical approaches for congenital heart disease in pediatric patients, 1669 cases of atrial septal defect, ventricular septal defect, or tetralogy of Fallot, which were corrected from January 1999 to December 2001, were classified according to approach (sternotomy, ministernotomy, or minithoracotomy). In cases of ventricular septal defect, the incidence of pulmonary complications was significantly higher in the minithoracotomy group than in the full sternotomy or ministernotomy groups. In patients with tetralogy of Fallot, hemoglobin concentration was higher, oxygen saturation was lower, and more patients required a transanular patch in the sternotomy group than in the other groups, but the clinical results were similar. Patients with complex defects or severe pulmonary hypertension should undergo a full sternotomy.

Cardiac Surgical Procedures↗
PubMed2003

Pulmonary blood distribution after total cavopulmonary connection of different types.

OBJECTIVE: To assess the feature of pulmonary blood flow distribution after total cavopulmonary connection (TCPC) of different types, and to provide the selection of the best type. METHODS: Thirty-two consecutive survival patients after TCPC underwent radionuclide lung perfusion imaging. According to the radionuclide counts in the left and right lungs, analyses of the distribution of blood flow from superior venous cava (SVC) and inferior venous cava (IVC) and the whole pulmonary blood flow in both lungs were made. All patients were divided into 4 groups by the the anastomosis between IVC and pulmonary artery. RESULTS: Group I: The flow ratio of the IVC to left lung was greater than that to the right lung, P < or = 0.01; the flow ratio of the SVC to right lung was greater than that to the left lung, P < or = 0.01; and the whole pulmonary blood flow went dominantly to the left lung, P < or = 0.05, which is not in line with physiological distribution. Group II: the flows from the SVC and IVC were mixed in the middle of the junction and ran evenly into the right and left lungs, the whole pulmonay blood flow went to both lungs, P > or = 0.05. Group III: the flow ratio of the SVC to both lungs were the same, P > or = 0.05, and major part from IVC went to the right lung, P < or = 0.01; the pulmonary blood flow go dominantly to the right lung, P < or = 0.05, which is in accord with physiological distribution. Group IV: the flows from the right SVC went to right lung by 100%, P < or = 0.01, and that from the left SVC went to left lung by 100% too, P < or = 0.01; the flows from IVC went dominantly to the left lung, with little part to the right lung, P < or = 0.05. CONCLUSIONS: Different types of TCPC can result in different pulmonary blood distributions. The best flow distribution between the left and right lungs can be obtained by an offset of the IVC anastomosis toward the RPA with widening anastomosis for the patients without persist left superior venous cava (PLSVC).

Adult↗