[Intra-arterial microorganism infection in patients with acute myocardial infarction and unstable angina pectoris].
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Adult↗
Biomedical subjects
Yang Li
Publications and source records attributed to Yang Li.
[Effects of free-air CO2 enrichment (FACE) on soil microbial biomass under rice-wheat rotation].
The effect of CO2 enrichment on soil microbial biomass in 0-5 cm and 5-10 cm soil layers under rice-wheat rotation was studied under the conditions of routine cultivation, irrigation and fertilization. The results showed that FACE treatment could significantly increase the amount of soil bacteria in 0-5 cm and 5-10 cm soil layers during rice jointing stage and wheat wintering and ripening stages. Elevated CO2 only significantly increased the amount of soil fungi in 0-5 cm soil layer during rice ripening stage. During the whole period of rotation, the amount of soil bacteria was greater than that of soil fungi.
Air↗
[Physical activity prevalence study in Shanghai city].
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Adolescent↗
Involvement of the PI 3-kinase signaling pathway in progression of colon adenocarcinoma.
The phosphoinositide 3-kinase (PI 3-kinase) signaling pathway has been shown to play a pivotal role in intracellular signal transduction pathways involved in cell growth, cellular transformation and tumorigenesis. Analysis of several colon adenocarcinoma cell lines indicates that the PI 3-kinase signaling pathway is up-regulated in colon cancers. In particular, the protein levels and phosphorylation status of Akt and p70 S6 kinase are up-regulated in colon adenocarcinoma cell lines. More significantly, we have demonstrated for the first time that the phosphorylation of FKHR, a downstream target of Akt, is increased in these cell lines. Intriguingly, phosphorylation of three components of the PI 3-kinase signaling pathway, namely Akt, p70 S6 kinase and FKHR, are in direct correlation with the degree of tumorigenic potential of the colon cell lines tested. No differences in the protein levels of the two subunits of PI 3-kinase, p85 and p110alpha, and PTEN were noted. Real-time quantitative PCR indicated an increase in levels of Akt message only, and not of the other signaling pathway components. Inhibition of the PI 3-kinase with wortmannin decreased the anchorage-independent growth of colon cells in a soft agar assay. Hence, the components of the PI 3-kinase signaling pathway could serve as potential candidates for drug development in treatment of colon cancer.
Adenocarcinoma↗
A synthesis of (+)-salvadione-A.
[reaction: see text] The p-benzoquinone shown is converted to the novel hexacyclic triterpene salvadione-A in four steps.
Benzoquinones↗
A new member of the tripartite multidrug efflux pumps, MexVW-OprM, in Pseudomonas aeruginosa.
OBJECTIVES: Multidrug efflux pumps are thought to be involved in mediating multidrug resistance in Pseudomonas aeruginosa. Here we aim to characterize hitherto uncharacterized multidrug efflux pumps from P. aeruginosa. MATERIALS AND METHODS: We isolated a mutant, YM442, which showed elevated resistance to several antimicrobial agents from P. aeruginosa YM44 lacking four major multidrug efflux pumps, MexAB, MexCD-OprJ, MexEF-OprN and MexXY. We cloned genes responsible for the resistance from chromosomal DNA of YM442 using YM44 as host. RESULTS: We designated the genes mexVW. Introduction of a recombinant plasmid pTAJ2 carrying the mexVW into YM44 cells conferred resistance to fluoroquinolones, tetracycline, chloramphenicol, erythromycin, ethidium bromide and acriflavine. Elevated ethidium bromide extrusion was observed with cells of YM442 and of YM44/pTAJ2. An outer membrane protein OprM was able to cooperate with MexVW. Elevated expression of the mexV gene was observed with YM442 compared with YM44. CONCLUSIONS: MexV (membrane fusion protein)-MexW (RND-type membrane protein)-OprM is a tripartite multidrug efflux pump. It is suggested that other outer membrane component(s) could cooperate with MexVW.
Bacterial Outer Membrane Proteins↗
The fourth blade within the beta-propeller is involved specifically in C3bi recognition by integrin alpha M beta 2.
Interactions between the complement degradation product C3bi and leukocyte integrin alpha M beta 2 are critical to phagocytosis of opsonized particles in host defense against foreign pathogens and certain malignant cells. Previous studies have mapped critical residues for C3bi binding to the I-domains of the alpha M and the beta2 subunits. However, the role of the alpha M beta-propeller in ligand binding remains less well defined, and the functional residues are still unknown. In the present study, we studied the function of the alpha M beta-propeller in specific ligand recognition by alpha M beta 2 using a number of different approaches, and we report four major findings. 1) Substitution of five individual segments (Asp398-Ala402, Leu412-Leu419, Tyr426-Met434, Phe435-Glu443, and Ser444-Thr451) within the W4 blade of the beta-propeller with their homologous counterparts in integrin alpha2 abrogated C3bi binding, whereas substitution of eight other segments outside this blade had no effect. 2) These five mutants defective in C3bi binding supported strong alpha M beta 2-mediated and cation-dependent cell adhesion to fibrinogen, suggesting that the conformations of these five defective mutants were intact. 3) Polyclonal antibodies recognizing sequences within the W4 blade significantly blocked C3bi binding by wild-type alpha M beta 2. 4) A synthetic peptide corresponding to Gln424-Gly440 within W4 interacted directly with C3bi. In conclusion, our data demonstrate that the W4 blade (residues Asp398 to Thr451) is involved specifically in C3bi but not fibrinogen binding to alpha M beta 2. Altogether, our study supports a model in which three separate domains of alpha M beta 2 (the alpha MI-domain, the alpha M beta-propeller, and the beta 2I-domain) function together and contribute to the formation of the C3bi-binding site.
Amino Acid Sequence↗
Sequences within domain II of the urokinase receptor critical for differential ligand recognition.
The receptor for urokinase-type plasminogen activator (uPAR) plays important roles in a number of physiological and pathological processes by virtue of its interactions with urokinase-type plasminogen activator (uPA), vitronectin (Vn), and several other proteins. The uPA binding site spans all three domains (D1 to D3) of uPAR. However, the nature of the Vn binding site within uPAR is still not clear. In this study, we conducted homolog-scanning mutagenesis on uPAR by switching 14 individual segments of 4-8 residues to their counterpart sequences of a uPAR homolog CD59. All 14 mutants were well expressed, reacted with a panel of monoclonal antibodies, and exhibited correct molecular weights. Of these 14 mutants, six mutants were defective in both uPA and Vn binding. Most importantly, we found two unique mutants uPAR(Asn172-Lys175) and uPAR(Glu183-Asn186) within the D2 domain, which displayed differential ligand binding activity: both had high affinity uPA binding, but completely lost Vn binding, indicating that these two sequences constitute a novel Vn binding site. Indeed, two peptides, P1 (153CPGSNGFHNNDTFHFLKC) and P2 (171CNTTKCNEGPILELENLPQ), derived from the sequences of the identified uPA and Vn binding pockets within D2, respectively, behaved like bona fide ligand binding sites: peptide P1 bound uPA but not Vn, whereas peptide P2 bound Vn and inhibited uPAR-mediated cell adhesion, but did not interact with uPA. Altogether, our data demonstrated that uPAR D2 contains two distinct ligand binding sites for uPA and Vn. Such information will help us better understand the complex roles of uPAR in cell adhesion, migration, and tumor metastasis.
Amino Acid Sequence↗
[The synthesis of MT in rat myocardial fibroblasts].
OBJECTIVE: To study the influence on the synthesis of metallothionein (MT) induced by lipopolysaccharide (LPS), basic fibroblast growth factor (bFGF), oxidized low-density lipoproteins (oxLDL) and ZnCl2 in rat myocardial fibroblasts. METHODS: The content of MT was measured by 109Cd-Hb saturation method and RT-PCR was used to determine the expression of MT mRNA. RESULTS: All of the stimulus in this experiment increased the synthesis of MT in myocardial fibroblasts. Compared with control, 1 and 5 mg.L-1 LPS increased the content of MT by 94% and 130% (P < 0.01), 0.2 and 1.0 mg.L-1 bFGF by 41% and 59% (P < 0.01), 2 and 10 mg.L-1 oxLDL by 23% (P < 0.05) and 41% (P < 0.01) respectively. 1,2 and 5 mg.L-1 ZnCl2 increased the content of MT by 66%, 99% and 149% (P < 0.01) in a concentration-dependent manner. 2-8 mg.L-1 ZnCl2 increased the content of MT1 mRNA by 69%-129%, MT2 mRNA by 31%-60% (P < 0.01). But 10 mg.L-1 ZnCl2 didn't stimulate the synthesis of MT more significantly, probably because ZnCl2 of high concentration damaged myocardial fibroblasts and decreased the survival rate of the cells. CONCLUSION: Many stimulus such as LPS, bFGF, oxLDL and ZnCl2 can induce the synthesis of MT, and ZnCl2 can increase the expression of MT mRNA in rat myocardial fibroblasts.
Animals↗
Songorine, a diterpenoid alkaloid of the genus Aconitum, is a novel GABA(A) receptor antagonist in rat brain.
Songorine, a diterpenoid alkaloid isolated from the genus Aconitum, was recently found to enhance the excitatory synaptic transmission in rat hippocampus. The mechanism underlying the effects was examined in the present study. The alkaloid at 0.1-300 microM inhibited the specific binding of [(3)H]muscimol to Triton-treated synaptic membranes of rat brain in a concentration-dependent manner (IC(50)=7.06 microM; 95% confidence limits: 3.28-10.84 microM). Scatchard analysis and Lineweaver-Burk double reciprocal plot of [(3)H]muscimol saturation binding data indicate a non-competitive inhibition of the alkaloid on the gamma-aminobutyric acid(A) (GABA(A)) receptor. In acutely dissociated rat hippocampal neurons the alkaloid did not elicit current response, but markedly inhibited the GABA-induced inward current (IC(50)=19.6 microM). The results suggest that songorine is a novel non-competitive antagonist at the GABA(A) receptor in rat brain.
Aconitum↗
Structure-based discovery of potassium channel blockers from natural products: virtual screening and electrophysiological assay testing.
Potassium ion (K(+)) channels are attractive targets for rational drug design. Based upon a three-dimensional model of the eukaryotic K(+) channels, the docking virtual screening approach was employed to search the China Natural Products Database. Compounds were ranked according to the relative binding energy, favorable shape complementarity, and potential of forming hydrogen bonds with the K(+) channel. Four candidate compounds found by virtual screening were investigated by using the whole-cell voltage-clamp recording in rat dissociated hippocampal neurons. When applied extracellularly, compound 1 markedly depressed the delayed rectifier K(+) current (I(K)) and fast transient K(+) current (I(A)), whereas compounds 2, 3, and 4 exerted a more potent and selective inhibitory effect on I(K). Intracellular application of the four compounds had no effect on both the K(+) currents.
Animals↗
Chemical rank estimation by noise perturbation in functional principal component analysist.
Some kinds of chemical data are not only univariate or multivariate observations of classical statistics, but also functions observed continuously. Such special characters of the data, if being handled efficiently, will certainly improve the predictive accuracy. In this paper, a novel method, named noise perturbation in functional principal component analysis (NPFPCA), was proposed to determine the chemical rank of two-way data. In NPFPCA, after noise addition to the measured data, the smooth eigenvectors can be obtained by functional principal component analysis (FPCA). The eigenvectors representing noise are sensitive to the perturbation, on the other hand, those representing chemical components are not. Therefore, by comparing the difference of eigenvectors obtained by FPCA with noise perturbation and by traditional principal component analysis (PCA), the chemical rank of the system can be achieved accurately. Several simulated and real chemical data sets were analyzed to demonstrate the efficiency of the proposed method.
Journal Article↗
Influences of dibutyryl cyclic adenosine monophosphate and forskolin on human sperm motility in vitro.
AIM: To study the influences of dibutyryl cyclic adenosine monophosphate (dbcAMP) and forskolin on human sperm motility in vitro. METHODS: Semen samples, aseptically obtained by masturbation and prepared by swim-up technique from 20 fertile men, were incubated with different concentrations of dbcAMP and forskolin at 37 deg. Measurements were carried out after 10 min, 20 min, 30 min and 60 min incubation. Motility parameters were estimated by using an automatic analyzing system. RESULTS: Treatment with dbcAMP or forskolin resulted in a significant increase in sperm motility and progressive motility. The larger the concentrations of dbcAMP or forskolin, the greater the effect appeared. The straight linear velocity and curvilinear velocity were not affected by both agents. CONCLUSION: dbcAMP and forskolin increase the motility and progressive motility of human sperm in vitro.
Adult↗
Effect of imidapril on heterogeneity of slow component of delayed rectifying K+ current in rabbit left ventricular hypertrophic myocytes.
AIM: To investigate the transmural heterogeneous change of slow component of delayed rectifying potassium current in rabbit left ventricular hypertrophic myocytes and the effect of long-term treatment with imidapril (Imi). METHODS: Rabbits were divided into hypertrophy group (left ventricular hypertrophy induced by partial ligation of abdominal aorta), Imi-treated group (surgical treatment as hypertrophy group was treated with Imi), and Sham-operated group as control. Whole-cell patch-clamp technique was used to record potassium currents. RESULTS: (1) Membrane capacitance was larger in hypertrophic cells than in sham-operated and Imi-treated cells. Action potential durations (APD) of epicardium (Epi), midmyocardium (M), and endocardium (Endo) were remarkably longer in hypertrophic cells than those in Imi-treated and sham-operated cells. The prolongation of APD90 of M was the most pronounced in three layer myocytes of hypertrophic group. (2) The densities of I(Ks,tail) of hypertrophic cells were reduced by Epi 25.3 %+/-2.9 %, M 38.0 %+/-3.7 % and Endo 20.3 %+/-4.7 % compared with those of sham-operated cells. The decrease of IKs,tail density was more pronounced in M than in Epi and Endo (n = 13, P<0.01 vs Epi or Endo). (3) The density of I(Kr,tail) in Imi-treated cells was not different from that in sham-operated cells significantly (n=10). CONCLUSION: Imi reduced prolongation of APD and inhibited the heterogeneous change of I(Ks,tail) in rabbit left ventricular hypertrophic myocytes.
Action Potentials↗
Effects of nuclear translocation of tissue transglutaminase and the release of cytochrome C on hepatocyte apoptosis.
OBJECTIVE: To assess the effects of nuclear translocation of tissue transglutaminase (TTG) and the release of cytochrome C on hepatocyte apoptosis and to reveal the mechanism of signal transduction of early apoptosis in injured hepatocytes. METHODS: Hepatocytes isolated from tissue transglutaminase gene knock-out mice and rats were stimulated with ethanol. Proteins from whole cell, cytoplasm and nuclei were extracted for determination of TTG activity by (14)C-putrescine incorporation. Distribution of TTG throughout the entire cell, as well as just nucleus was observed under a confocal scanning microscope. The amount of cytochrome C released from mitochondria was determined by ELISA. Cell apoptosis was observed by fluorescent cytochemistry. RESULTS: TTG activity in whole cells and nuclei was significantly increased after the hepatocytes were treated with ethanol. Cytochrome C release was remarkably increased in the cells isolated from rat and wild-type mouse after treatment with ethanol but not in TTG gene knock-out mice. Cellular apoptosis appeared in hepatocytes isolated from rats and wild-type mice but not in the hepatocytes from TTG gene knock-out mice after stimulation with ethanol. CONCLUSIONS: Increased TTG in hepatocytes can be translocated into the nucleus and promote release of mitochondrial cytochrome C into the cytoplasm. Passing through a series of signal pathways, hepatocyte apoptosis is induced eventually.
Animals↗
[Clinical evaluation of propess for induction of term pregnancy].
OBJECTIVE: To explore the efficacy and safety of continuously released prostaglandin E(2) (PGE(2)) suppository-propess used for induction of term pregnancy. METHODS: A multicenter, prospective, case control clinical study was carried out, propess was used in 100 cases as study group, the suppository without PGE(2) was used in 49 cases as control group. The cervical maturity (by Bishop scoring), the time to labor starting, membrane rupture and delivery, the application of oxytocin, ceserean section rate, fetal and neonatal condition were compared between 2 groups after inserting of the suppository. At the same time, side effects caused by propess were investigated. RESULTS: Bishop score was increased >or= 2 points in 93% cases, >or= 3 points in 87% cases in study group, whereas only 4% cases whose Bishop score increased >or= 2 points in control group. The time to labor starting, membrane rupture, and delivery was shortened obviously in study group than that in control group after inserting suppository. The application of oxytocin was much less in study group, cesarean section rate was reduced in study group (32% vs 61%). There was no significant difference between 2 groups in fetal and neonatal conditions. The overstimulation of uterine contraction and mild gastrointestinal tract reaction occurred in 3 cases and 2 cases respectively in study groups. CONCLUSION: Propess can be used for induction of term pregnancy effectively and safely.
Adult↗
[Impact of aldicarb and its complex pollution on DNA of zebrafish embryo].
This paper deals with the impact of a complex pollution system composed of a very toxic carbamate pesticide, aldicarb and the widely used anionic surfactant, sodium dodecylbenzenesulfonate(SDBS), on DNA of zebrafish (Brachydanio rerio) embryo. The results indicated that DNA damage caused by aldicarb became more serious with its increasing concentration, but single-strand break caused by aldicarb in low concentration and short time could be repaired, and high concentration led to double-strand break which was difficult to repaire. SDBS in certain concentration (20 mg.L-1) could reduce the toxicity of aldicarb in the complex pollution system.
Aldicarb↗
[Species composition and ecological distribution of planktonic diatoms in the Changjiang River estuary during spring].
53 water samples were collected from 28 stations in typical regions where redtide frequently occurred in the Changjiang River estuary during Spring, 2002. In total, 80 diatom species and varieties belonging to 31 genera were identified, among which, genera with high species biodiversity included Coscinodiscus which contained 17 species and Pleurosigma which contained 8 species and varieties. Quantitative analysis of diatom cell density showed that Pseudo-nitzschia delicatissma (3.48 x 10(3) cells.L-1, 28.54%), Melosira sulcata (1.43 x 10(3) cells.L-1, 16.98%) and Pseudo-nitzschia pungens (0.71 x 10(3) cells.L-1, 9.85%) were dominant species, which occurred at almost all stations. Higher cell density of Pseudo-nitzschia delicatissma and Pseudo-nitzschia pungens occurred at stations along 123 degrees E, while that of Melosira sulcata occurred at stations around Changjiang River at 31-32 degrees N. The total diatom cell density ranged from 0.43 x 10(3)-23.3 x 10(3) cells.L-1, with average of 4.61 x 10(3) cells.L-1. At station DD15 located at 123 degrees E and 30.5 degrees N, the highest diatom cell density was found, which was 1.85 x 10(4) cells.L-1 at surface water layer, and 2.33 x 10(4) cells.L-1 at middle water layer (30 m) respectively. Horizontally, the diatom cell density showed scattered distribution, while vertically, it was commonly higher at surface water layer than that at middle water layer.
Biodiversity↗