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Biomedical subjects

Qi Zhang

Publications and source records attributed to Qi Zhang.

At least 55 records · Page 3Linked to original sources

Outcomes of primary percutaneous coronary intervention for acute ST-elevation myocardial infarction in patients aged over 75 years.

BACKGROUND: The optimal reperfusion strategy in elderly patients with ST-elevation myocardial infarction (STEMI) remains unclear. The purpose of this study was to evaluate the safety, in-hospital and one-year clinical outcomes for patients > 75 years of age with STEMI receiving primary percutaneous coronary intervention (PCI), compared with those treated by conservative approach. METHODS: One hundred and two patients > 75 years of age with STEMI presented < 12 hours were randomly allocated to primary PCI (n = 50) or conservative therapy only (n = 52). The baseline characteristics, in-hospital outcome and major adverse cardiac events (MACE), including death, non-fatal myocardial infarction and target vessel revascularization at one-year clinical follow-up were compared between the two groups. RESULTS: Age, gender distribution, risk factors for coronary artery disease, infarct site and clinical functional status were similar between the two groups, but the patients in primary PCI group received less low-molecular-weight heparin during hospitalization. Compared with conservative group, the patients in primary PCI group had significantly lower occurrence rate of re-infarction and death and shortened hospital stay. The composite endpoint for in-hospital survivals at 30-day follow-up was similar between the two groups, but one-year MACE rate was significantly lower in the primary PCI group (21.3% and 45.2%, P = 0.029). Left ventricular ejection fraction was not significantly changed in both groups during follow-up. Multivariate analysis revealed that primary PCI (OR = 0.34, 95% CI: 0.21 - 0.69, P = 0.03) improved MACE-free survival rate for STEMI patients aged > 75 years. CONCLUSION: Our results indicated that primary PCI was safe and effective in reducing in-hospital mortality and one-year MACE rate for elderly patients with STEMI.

Aged↗

Long term clinical outcomes in patients with moderate renal insufficiency undergoing stent based percutaneous coronary intervention.

BACKGROUND: Patients with end-stage renal disease have a high mortality from coronary artery disease, but the impact of moderate renal insufficiency on clinical outcomes after percutaneous coronary intervention (PCI) and the effect of drug-eluting stent implantation in these patients remain unclear. This study determined the long-term effect of moderate renal insufficiency on death and major adverse cardiac events (MACE) after stent based PCI and examined whether drug-eluting stent implantation could favourably influence clinical outcome. METHODS: Major adverse cardiac events and causes of mortality were determined for 1012 patients undergoing percutaneous intervention from January 1, 2002 to December 31, 2004 at Shanghai Ruijin Hospital. Based on estimated creatinine clearance levels, long term outcomes were compared between patients with estimated creatinine clearance < 60 ml/min (renal insufficiency group; n = 410) and those with estimated creatinine clearance > or = 60 ml/min (control group; n = 602). Subgroup analysis was also made for patients with renal insufficiency between drug eluting stent (n = 264) and bare metal stent implantation (n = 146) during PCI. RESULTS: During follow-up (average 17 months) after successful PCI, all causes of death (7.1% vs 2.3%, P < 0.01) and cardiac death (3.4% vs 1.0%, all P < 0.01) were significantly higher in renal insufficiency group than in control group. For patients with moderate renal insufficiency, drug-eluting stent implantation reduced significantly all causes of death (5.3% vs 10.9%, P < 0.05) and occurrence of major cardiac adverse events (15.1% vs 24.6%, P < 0.05) compared with bare metal stents. CONCLUSIONS: Moderate renal insufficiency is an important clinical factor influencing the mortality after PCI in patients with coronary artery disease and the use of drug-eluting stents should be the preferred therapy for the improvement of long-term outcomes in such patients.

Aged↗

Estimating sampling frequency in pollen exposure assessment over time.

A time series model was fitted to the pollen concentration data collected in the Greater Cincinnati area for the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS). A traditional time series analysis and temporal variogram approach were applied to the regularly spaced databases (collected in 2003) and irregularly spaced ones (collected in 2002), respectively. The aim was to evaluate the effect of the sampling frequency on the sampling precision in terms of inverse of standard error of the overall level of mean value across time. The presence of high autocorrelation in the data was confirmed and indicated some degree of temporal redundancy in the pollen concentration data. Therefore, it was suggested that sampling frequency could be reduced from once a day to once every several days without a major loss of sampling precision of the overall mean over time. Considering the trade-offs between sampling frequency and the possibility of sampling bias increasing with larger sampling interval, we recommend that the sampling interval should take values from 3 to 5 days for the pollen monitoring program, if the goal is to track the long-term average.

Air Pollution↗

Activation and sensitization of C and Adelta afferent fibers mediated by P2X receptors in rat dorsal skin.

The present study investigated the activation and sensitization effects of local injection of P2X receptor agonist alpha,beta-methylene ATP (alphabeta-meATP) into the receptive fields of afferent fibers innervating dorsal hairy skin in anesthetized rats. Single unit activities of afferent fibers were recorded by means of isolation of the fiber filaments from the dorsal cutaneous nerve branch. A total of 237 fibers were obtained. Of these, 67 were classed as C fibers, 104 as Adelta fibers and 66 as Abeta fibers. When alphabeta-meATP (0.1-100 microM, 10 microl) was injected subcutaneously into the receptive fields of these units, C and Adelta fibers demonstrated a dose-related increase in the discharge rates of the response. The activated proportion of C and Adelta fibers with a response to the drug also increased with dose. However, Abeta fibers did not exhibit significant activation. Furthermore, injection of alphabeta-meATP (10 microl) at a concentration of 100 microM resulted in a significant decrease of mechanical thresholds in C and Adelta fibers compared with pre-injection baseline (P < 0.05). In control experiments, injection of the vehicle phosphate-buffered saline (PBS, 10 microl) had no effect on all units tested. alphabeta-meATP (100 microM, 10 microl) followed by pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), a P2X receptor antagonist, successfully blocked the activation and sensitization effects of alphabeta-meATP on C and Adelta fibers tested. These results suggest that peripheral P2X receptors are involved in mediating peripheral excitation of C and Adelta fibers.

Action Potentials↗

Theory and simulation of wave phase conjugation.

This paper briefly presents the general analytical solution for the resonant modes in 1D active magneto acoustic phase conjugators in contact with passive media of arbitrary impedance. The first non-resonant but amplified modes are also derived. All results are successfully compared with direct numerical simulations.

Journal Article↗

Effects of endogenous beta-amyloid overproduction on tau phosphorylation in cell culture.

Alzheimer's disease is characterized by beta-amyloid (Abeta) overproduction and tau hyperphosphorylation. Recent studies have shown that synthetic Abeta promotes tau phosphorylation in vitro. However, whether endogenously overproduced Abeta promotes tau phosphorylation and the underlying mechanisms remain unknown. Here, we used mouse neuroblastoma N2a stably expressing wild-type amyloid precursor protein (APPwt) or the Swedish mutant APP (APPswe) to determine the alterations of phosphorylated tau and the related protein kinases. We found that phosphorylation of tau at paired helical filament (PHF)-1, pSer396 and pThr231 epitopes was significantly increased in cells transfected with APPwt and APPswe, which produced higher levels of Abeta than cells transfected with vector or amyloid precursor-like protein 1. The activity of glycogen synthase kinase-3 (GSK-3) was up-regulated with a concomitant reduction in the inhibitory phosphorylation of GSK-3 at its N-terminal Ser9 residue. In contrast, the activity of cyclin-dependent kinase-5 (CDK-5) and protein kinase C (PKC) was down-regulated. Inhibition of GSK-3 by LiCl, but not inhibition of CDK-5 by roscovitine, arrested Abeta secretion and tau phosphorylation. Inhibition of PKC by GF-109203X activated GSK-3, whereas activation of PKC by phorbol-12,13-dibutyrate inhibited GSK-3. These results suggest that endogenously overproduced Abeta induces increased tau phosphorylation through activation of GSK-3, and that inactivation of PKC is at least one of the mechanisms involved in GSK-3 activation.

Amyloid beta-Protein Precursor↗

[Mechanism of signal transduction of differentiation of mesenchymal stem cells into cytokeratin-expressing epidermoid cells].

OBJECTIVE: To investigate the role of the signal routes P38, ERK, and Rho in the differentiation of bone marrow mesenchymal stem cells (MSCs) into epidermoid cells. METHODS: (1) MSCs were separated from the bone marrow of Wistar rats by Ficoll-Pague lymphocyte separating medium and proliferated in culture medium. Then the MSCs were immunocytochemically stained to detect the expression of surface antigens. (2) The MSCs were randomly divided into 3 groups: control group; pure induction induced group, cultured with epithelial growth factor (EGF) added into the culture fluid, and Rho inhibition group, cultured with EGF and HA1077, a ROK inhibitor, added into the culture fluid. One, 3, 5, and 7 days later FC was used to detect the levels of phosphorylated P38 and ERK. (3) MSCs were randomly divided into 4 groups: control group, cultured with low-sugar DMEM complete culture fluid; pure induction group, cultured with supernatant of rat fibroblasts and EGF added into the culture fluid, p38 blocking group, with SB203580, inhibitor of P38 added into the culture fluid; and ERK blocking group, with PD98059, inhibitor of ERK added into the culture fluid. Seven days later, SP method was used to detect the expression of CK5/8 and CK19 induced by MSCs. (4) MSCs were randomly divided into 4 groups: control group; pure induction group, with supernatant of rat fibroblasts and EGF added into the culture fluid; and RHO blocking group, with HA1007 added into the culture fluid. Seven days later, FC was used to detect the expression of CK5/8 and CK19. RESULTS: (1) Both FC and immunocytochemistry showed that the MSCs were uniformly positive in CD29 and CD44, but did not express CD34 and CD45. (2) The phosphorylated P38 rate remained 0.01% in the control group. The phosphorylated P38 rate was 0.04%, significantly higher than that of the control group (0.01%, P < 0.05) at day 5, and then lowered to 0.01% at day 5 in the pure induction group; and became 6.17%, 4.13%, 3.97%, and 0.41% respectively at day 1, 3, 5, and 7, all significantly higher than those of the control group (all P < 0.05), in the Rho inhibition group. The phosphorylated ERK level was 4.23% in the control group; became 0.39% and 0.40% at day 3 and day 5 (both P < 0.05), and then returned to 5.10% at day 7 in the pure induction group; and was not significantly changed at days 1, 3, and 5, and then became 0.41%, significantly lower than that of the control group (P < 0.05), in the Rho blocking group, (3) The control group was CK5/8 and CK19 negative. The CK5/8 and CK19 rates at day 7 of the pure induction group were 3.01% and 6.47% respectively, both significantly higher than those of the p38 inhibition group (1.43% and 5.41% respectively, both P < 0.05). The CK5/8 and CK19 expression rates of the ERK inhibition group were 5.54% and 7.56% respectively, both significantly higher than those of the pure induction group (both P < 0.05), (4) The CK5/8 and CK19 expression rates of the HA1077 group were 21.65% and 39.41% pure, both significantly higher than those of the pure induction group (1.81% and 10.19% respectively, both P < 0.05). CONCLUSION: p38 route may play an active role in the differentiation of MSCs into epidermoid cells. Blocking of the upstream signal Rho may enhance the activation of p38 route and then promote the differentiation of MSCs into epidermoid cells.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

A coarse-grained model for the formation of alpha helix with a noninteger period on simple cubic lattices.

Periodicity is an important parameter in the characterization of a helix in proteins. In this work, a coarse-grained model for a homopolypeptide in simple cubic lattices has been extended to build an alpha helix with a noninteger period. The lattice model is based on the bond fluctuation algorithm in which bond lengths and orientations are altered in a quasicontinuous way, and the simulation is performed via dynamic Monte Carlo simulation. Hydrogen bonds are assumed to be formed between a virtual-carbonyl group in a residue and a downstream virtual-imino group in another residue. Consequently, the period of the formed alpha helix is a noninteger. An improved spatial correlation function has been suggested to quantitatively describe the periodicity of the helical conformation, by which helical period and helical persistent length can be calculated by statistics. The resultant periods are very close to 3.6 residues; the persistent length based upon the improved definition can be larger or smaller than the chain length and reflect the inherent regularity of a chain including one or multiple helical blocks. The simulation outputs agree with the calculation of the Zimm-Bragg theory based upon the associated nucleation parameter and propagation parameter as well.

Algorithms↗

Regulation of membrane-associated prostaglandin E2 synthase 1 in pregnant sheep intrauterine tissues by glucocorticoid and estradiol.

This study was designed to determine the regulatory effect of glucocorticoid and estradiol on expression of ovine intrauterine membrane-associated prostaglandin E(2) synthase 1 (mPTGES1) in late gestation and at labor. For gestational and labor groups, 16 pregnant ewes from 95-147 d gestational age (dGA) and four pregnant ewes at spontaneous term labor were used. The fetal glucocorticoid group, 14 pregnant ewes at 123-125 dGA with fetuses, was divided into the following groups: after sham adrenalectomy (n = 5), adrenalectomy (n = 4), and adrenalectomy with fetal cortisol replacement to late gestation levels (n = 5). For the maternal glucocorticoid group, nine pregnant ewes were treated with saline (n = 4) and three courses of maternal dexamethasone (n = 5). For the estradiol group, 10 pregnant ewes at 119-121 dGA were treated with sesame oil (n = 5) or estradiol (n = 5) to produce labor levels of estradiol in maternal plasma. Endometrial, myometrial, and placental mRNA and proteins were analyzed by Northern and Western blot and immunocytochemistry for mPTGES1. Data were analyzed by Student's t test and ANOVA. There was a significant increase of placental mPTGES1 in late gestation. Glucocorticoids, given to the mother or fetus, significantly stimulated mPTGES1 in placenta. mPTGES1 was elevated only in the endometrium during spontaneous term labor and after estradiol treatment. The mPTGES1 was localized in the myometrial smooth muscle cells, endometrial stromal cells, and placental trophoblast cells. Our study suggested that increased expression of placental mPTGES1 throughout late gestation might result from the increased fetal and maternal circulating glucocorticoids, whereas elevated maternal plasma estradiol concentration might be responsible for the induced mPTGES1 expression in the endometrium during labor.

Adrenalectomy↗

[Impact of calcified lesion on the intimal hyperplasia after implantation of drug eluting stent: an intravascular ultrasound study].

OBJECTIVE: To investigate the impact of calcified lesion on the intimal hyperplasia after implantation of drug eluting stent. METHODS: Ninety-nine rapamycin-eluting stents were implanted into the left anterior descending branches of coronary artery of 97 patients with 99 lesions. Eight months later intravascular ultrasound (IVUS) was used to examine the cross section area (CSA) of the external elastic membrane (EEM) at the stent inlet and at the stent outlet, in-stent CSA, CSA of the lumen, area of neo-intima (in-stent area minus lumen CSA), the maximum and minimum diameters of stent, and symmetry index of stent (minimal diameter of stent/maximum diameter of stent). RESULTS: Forty-one lesions were calcified and 58 non-calcified. Fourteen of the 99 lesions in the 97 patients developed intimal hyperplasia. The inlet stent CSA of the calcified group was (7.30 +/- 1.94) mm(2), similar to that of the non-calcified group (6.58 +/- 1.96) mm(2); the outlet CSA of the calcified group was (6.74 +/- 2.02) mm(2), similar to that of the non-calcified group (6.14 +/- 1.82) mm(2). The minimum stent CSA of the calcified group was (4.97 +/- 1.51) mm(2), significantly smaller than that of the non-calcified group (6.10 +/- 1.87) mm(2) (P < 0.05), the symmetry index of the calcified group was 0.92 +/- 0.07, significantly lower than that of the non-calcified group (0.92 +/- 0.07, P < 0.05), and the intimal area of the calcified group was (0.02 +/- 0.20) mm(2), significantly smaller than that of the non-calcified group (0.53 +/- 1.50) mm(2) (P < 0.05). CONCLUSION: Drug eluting stent implantation in the patients with calcified lesions has a less stent CSA and poor symmetry, and less intimal hyperplasia compared with those in the non-calcified lesions.

Aged↗

Effect of WeiJia on carbon tetrachloride induced chronic liver injury.

AIM: To study the effect of WeiJia on chronic liver injury using carbon tetrachloride (CCl(4)) induced liver injury animal model. METHODS: Wistar rats weighing 180-220g were randomly divided into three groups: normal control group (Group A), CCl(4) induced liver injury control group (Group B) and CCl(4) induction with WeiJia treatment group (Group C). Each group consisted of 14 rats. Liver damage and fibrosis was induced by subcutaneous injection with 40% CCl(4) in olive oil at 3 mL/kg body weight twice a week for eight weeks for Groups B and C rats whereas olive oil was used for Group A rats. Starting from the third week, Group C rats also received daily intraperitoneal injection of WeiJia at a dose of 1.25 microg/kg body weight. Animals were sacrificed at the fifth week (4 male, 3 female), and eighth week (4 male, 3 female) respectively. Degree of fibrosis were measured and serological markers for liver fibrosis and function including hyaluronic acid (HA), type IV collagen (CIV), gamma-glutamyl transferase (gamma-GT), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined. Alpha smooth muscle actin (alpha-SMA) and proliferating cell nuclear antigen (PCNA) immunohistochemistry were also performed. RESULTS: CCl(4) induction led to the damage of liver and development of fibrosis in Group B and Group C rats when compared to Group A rats. The treatment of WeiJia in Group C rats could reduce the fibrosis condition significantly compared to Group B rats. The effect could be observed after three weeks of treatment and was more obvious after eight weeks of treatment. Serum HA, CIV, ALT, AST and gamma-GT levels after eight weeks of treatment for Group C rats were 58+/-22 microg/L (P<0.01), 57+/-21 microg/L (P<0.01), 47+/-10 U/L (P<0.01), 139+/-13 U/L (P<0.05) and 52+/-21 U/L (P>0.05) respectively, similar to normal control group (Group A), but significantly different from CCl(4) induced liver injury control group (Group B). An increase in PCNA and decrease in alpha-SMA expression level was also observed. CONCLUSION: WeiJia could improve liver function and reduce liver fibrosis which might be through the inhibition of stellate cell activity.

Actins↗

Immune gene-viral therapy with triplex efficacy mediated by oncolytic adenovirus carrying an interferon-gamma gene yields efficient antitumor activity in immunodeficient and immunocompetent mice.

Among numerous gene therapeutic strategies for cancer treatment, gene transfer by conditionally replicative adenovirus (CRAd) of interferon-gamma (IFN-gamma) may be useful because of the possibility that it will yield IFN-gamma-mediated antiangiogenesis, immune responses, and CRAd-mediated oncolysis. In this study, we constructed a human TERT promoter-mediated oncolytic adenovirus targeting telomerase-positive cancers and armed with a mouse or human IFN-gamma gene to generate novel immune gene-viral therapeutic systems, CNHK300-mIFN-gamma and CNHK300-hIFN-gamma, respectively. The systems can specifically target, replicate in, and lyse cancer cells, while sparing normal cells. The advantage of these systems is that the number of transgene copies and their expression increase markedly via viral replication within infected cancer cells, and replicated viral progeny can then infect additional cancer cells within the tumor mass. CNHK300-mIFN-gamma induced regression of xenografts in liver cancer models in both immunodeficient and immunocompetent mice by triplex mechanisms including selective oncolysis, antiangiogenesis, and immune responses. We conclude that combining immune gene therapy and oncolytic virotherapy can enhance antitumor efficacy as a result of synergism between CRAd oncolysis and transgene composite antitumor responses.

Adenoviridae↗

Resolving the motional modes that code for RNA adaptation.

Using a domain elongation strategy, we decoupled internal motions in RNA from overall rotational diffusion. This allowed us to site-specifically resolve a manifold of motional modes in two regulatory RNAs from HIV-1 with the use of nuclear magnetic resonance spin relaxation methods. Base and sugar librations vary on a picosecond time scale and occur within helical domains that move collectively at diffusion-limited nanosecond time scales. Pivot points are short, functionally important, and highly mobile internal loops. These spontaneous changes in RNA conformation correlate quantitatively with those that follow adaptive recognition of diverse targets. Thus, ligands may stabilize existing RNA conformations rather than inducing new ones.

Arginine↗

Caries experience variables as indicators in caries risk assessment in 6-7-year-old Chinese children.

OBJECTIVES: The aim of the present study is to investigate variables of the past caries experience as indicators of future caries in a Chinese child population. METHODS: Caries was recorded at baseline and 2 years later in 433, 6-7-year-old Chinese children. Correlation coefficients between variables of the past caries experience and caries increment were calculated. Stepwise logistic regression analyses provided predictor variables. ROC curves presenting sensitivity as function of (100-specificity) were employed to summarize the obtained information. The area under the ROC curves was used as a measure of predictive accuracy. RESULTS: Twelve variables of baseline caries experience had a significant (p<or=0.05) correlation with caries increment in the permanent dentition. Among the variables, the number of primary molars with enamel or dentine caries, fillings or missings due to caries (d(12)mftmol), the number of fissures of the first permanent molar with enamel caries (D(1)fis) and the number of pits and fissures of the first permanent molar with dentine caries (D(2)pitfis) were the most powerful caries predictors, which resulted in a value of 0.74 under the ROC. CONCLUSIONS: By including non-cavitated caries in the past caries experience of primary molars and permanent first molars, it was possible to construct a screening criterion (d(12)mftmol+D(1)fis+D(2)pitfis), which enabled the selection of true negative children and the selection of a high caries risk group in a 6-7-year-old Chinese child population.

Child↗