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Biomedical subjects

Ying Zhang

Publications and source records attributed to Ying Zhang.

At least 307 records · Page 17Linked to original sources
PubMed2005

[Effect of Salviae miltiorrhizae on mRNA expression of inducible nitric oxide synthase and organ injury in rats with severe acute pancreatitis].

OBJECTIVE: To investigate the relationship between mRNA expression of inducible nitric oxide synthase (iNOS) and organ injury, and the effect of Salviae Miltiorrhizae on iNOS mRNA in severe acute pancreas (SAP) rats. METHODS: Forty-five Wistar rats were randomly divided into 3 groups, the model group (MG), the Salviae Miltiorrhizae group (SMG), and the control group (CG), with 15 rats in each group. Rats in MG and SMG were established to SAP model by intraductal injection with 5% sodium taurocholate in a dose of 1.0 ml/kg, while rats in CG were merely performed sham-operation. Immediately after modeling, rats in SMG were injected with Salviae Miltiorrhizae injection (SMI) 2 ml/kg every 6 h for 4 times in total, but to rats in other two groups same volume of normal saline were administered. The level of serum amylase (AMY), nitric oxide (NO) and the volume of ascites of rats were determined 24h after modeling, and intensity of iNOS mRNA expression in pancreas, lung and kidney were detected in the same time using in situ hybridization and image analysis. The pathologic change was observed as well. RESULTS: The volume of ascites and serum levels of AMY and NO in MG were significantly higher then those in SMG and CG (P < 0.05 and P <0.01). The expression of iNOS mRNA in pancreas, lung and kidney increased in MG and SMG, it was significantly higher in MG than that in SMG. And the pathological change of pancreas, lung and kidney in SMG was milder than that in MG. CONCLUSIONS: Over-expression of iNOS mRNA could cause excessive synthesis of NO, and lead to injury of pancreas, lung and kidney in SAP. Salviae Miltiorrhizae in early stage of the disease can inhibit the over-expression of iNOS mRNA to ameliorate the injury of the pancreas, lung and kidney.

Animals↗
PubMed2005

[A clinical study on CD178 positive T lymphocyte in hemorrhagic fever with renal syndrome].

BACKGROUND: To further probe into the role of CD178 in the pathogenesis of hemorrhagic fever with renal syndrome (HFRS). METHODS: The expression of CD178 and HLA-DR on T cell subsets in peripheral blood of patients with HFRS and their dynamic changes were detected by Flow cytometry. RESULTS: CD4+ CD178+ and CD8+ CD178+ T lymphocytes both in fever and polyuria phases were significantly higher than those in normal controls, while there was no significant difference between the both phases of HFRS (P > 0.05). CD178 expression on CD4+ HLA-DR+ and CD8+ HLA-DR+ T lymphocytes were significantly higher than those in normal controls (P < 0.05, P < 0.01, P < 0.001, P < 0.001), while there was no significant difference between CD4+ HLA-DR+ and CD8+ HLA-DR+ T lymphocytes (P > 0.05). CONCLUSION: CD178 was expressed on both CD4+ and CD8+ T cell subsets, but mainly on CD8+ T cell subsets both in early stage and in later stage in the pathogenesis of HFRS. Cytotoxic T lymphocyte (CTL) might kill target cells infected by hantavirus (HV) and eliminate HV via cell apoptosis mediated by CD178 in early stage of HFRS. In later stage of HFRS, CD178 might reduce antigen-specific T lymphocytes by activation induced cell death (AICD) and help to maintain the homeostasis of immune system.

Adolescent↗
PubMed2005

[Construction of a virulence-related gene library of Streptococcus mutans by suppression subtractive hybridization].

OBJECTIVE: To construct a suppression subtractive library of virulence-related genes from c serotype Streptococcus mutans (S. mutans), and lay foundations for screening the virulent genes. METHODS: After being isolated from virulent and avirulent strain of S. mutans respectively, the intact and high-pure genomic DNA was digested with three appropriate four-base-cutting restriction endonueleases to produce fragments of optimal length. The digested DNA of the virulent strain ligated with adaptor was used as tester DNA, and that of the avirulent strain as driver DNA. Then the suppression subtractive hybridization was carried out, and the efficiency of ligation and subtraction detected respectively. The subtracted fragments were inserted into vector pCR2. 1 using T/A cloning kit, and transformed into E. coli TOP10F' competent cells. Those white colonies were selected to construct the suppression subtractive library. RESULTS: Alu I chosen from three restriction endonucleases was verified to be suitable for preparing restriction fragments from S. mutans genomic DNA. Through electrophoresis of Alu I -digested DNA, a smear ranged from 0.1 to 2.0 kb was observed. The ligation efficiency of tester DNA with adaptor was at least higher than 25 percent. The subtraction efficiency of suppression subtractive hybridization confirmed the success in enrichment of differential genes between virulent and avirulent strain of S. mutans. In the subtracted group, the appearance time of the 23S rRNA gene both in tester and driver DNA was later than that in the unsubtracted group by six cycles. It suggested that suppression subtractive hybridization happened indeed. After the subtracted fragments were cloned, 96 colonies were picked up for constructing the suppression subtractive library of virulence-related genes of S. mutans. CONCLUSION: Suppression subtractive hybridization allows rapid and easy construction of virulence-related gene library of S. mutans.

Escherichia coli↗
PubMed2005

[Synthesis of camptothecin glycosides by phase transfer-catalysis and its inhibitory activity against topo I].

AIM: To find new anticancer drug based on the structure of 10-hydroxy camptothecin. METHODS: Six camptothecin glycosides (7-12) were synthesized by phase transfer catalysis. The structures of all compounds synthesized were determined by 1H NMR, IR and MS. Their antitumor activity was evaluated on cancer cells in vitro, and inhibitory activity against Topo I was evaluated by molecular biologic method. RESULTS AND CONCLUSION: The result indicated that the yield of camptothecin glycosides by phase transfer catalysis is much higher than by the method from literature, camptothecin glycosides have much lower cytotoxicities on cancer cell in vitro, but have better inhibitory activity of topo I.

Antineoplastic Agents, Phytogenic↗
PubMed2005

External approach microsurgery of retinal dialysis.

PURPOSE: To explore the effect of external approach microsurgery in retinal dialysis. METHODS: Consecutive 30 eyes of 28 patients with retinal dialysis were enrolled for this study. The progresses of the external approach microsurgery were following. Under the surgical microscopy, the preplacement of mattress sutures for buckling and/or encircling following retrobulbar anesthesia and scleral exposure, draining subretinal fluid, the cryotherapy of retinal breaks, checking the position of breaks on scleral buckle and gases injection were performed in turn. RESULTS: After drainage of subretinal fluid, with scleral depression cryotherapy reaction around breaks could be observed clearly under the microscopy. All breaks were located on anterior slope of the buckle. Intraoperative complications were mild subretinal hemorrhage at drainage site and corneal epithelium exfoliation in 3 eyes, respectively. Postoperative complications were mainly secondary glaucoma and retinal redetachment. The one-operation reattachmentl rate was 96.7% (29 eyes), and the final reattachment rate was 100% after one eye had a second external approach microsurgery. The postoperative vision acuity (VA) was significantly better than the preoperative VA (chi(2)= 9.529, P< 0.01). CONCLUSION: External approach microsurgery has favourable effect on the surgery of retinal dialysis.

Adolescent↗
PubMed2004

Structure of an excitatory insect-specific toxin with an analgesic effect on mammals from the scorpion Buthus martensii Karsch.

BmK IT-AP is an excitatory insect-specific beta-toxin with analgesic effect from the Chinese scorpion Buthus martensii Karsch (BmK) and consists of 72 residues cross-linked by four disulfide bridges. The crystal structure of BmK IT-AP has been determined at a resolution of 2.6 A by molecular replacement. Compared with the mammal-selective alpha-toxins consisting of 64 residues from the scorpion BmK, the general fold of IT-AP features an additional one-and-a-half turn alpha-helix at the C-terminal residues 59-65 with a shifted disulfide bridge Cys38-Cys64. The extension and 'wiggling' of the C-terminal segment led to a reshaping of the bioactive surface, including the complete destruction of the active site RC comprising the reverse turn (8-12) and C-terminal residues 58-64, the disappearance of an active surface formed by two aromatic residues Trp38 and Tyr42 and the covering of the conserved aromatic cluster Tyr5, Tyr35 and Trp47, which are all critical for the structure and function of mammal-selective alpha-toxins. Bj-xtrIT, the only other excitatory insect-specific toxin whose three-dimensional structure has been determined, is distinct from BmK IT-AP. A functionally important five-residue alpha-helix (alpha0) formed by residues 17-21 in Bj-xtrIT is deleted in BmK IT-AP and helix alpha1 is immediately connected to Cys16 through two residues Leu17 and Phe18. Accordingly, the functional surface of this region in Bj-xtrIT has also been reshaped in IT-AP, which implies subtle differences between BmK IT-AP and Bj-xtrIT in binding to the receptor, although most other critical residues for structure and function adopt almost identical conformations. The crystal structure of IT-AP also forms a sound basis for further study of the structure-function determinants of the analgesic effect.

Amino Acid Sequence↗
PubMed2004

Fluorescent sensor for imidazole derivatives based on monomer-dimer equilibrium of a zinc porphyrin complex in a polymeric film.

A new zinc(II) porphyrin conjugate with an appended pyrene subunit has been synthesized and shown to exhibit significant and analytical usefulness for fluorescence sensing toward imidazole derivatives. The molecular recognition was based on the bridging interaction of the imidazole ring of analyte with the zinc(II) center of the porphyrin, while the transduction signal for the recognition process was the pyrene excimer fluorescence. The sensor was constructed and applied for fluorescence assay of histidine in aqueous solution by immobilizing the sensing material in a plasticized PVC membrane. When the membrane was bathed in an alkaline solution void of histidine, zinc(II) porphyrin was present in the monomer form, and pyrene emitted monomer fluorescence at 378 and 397 nm. With the presence of histidine in the sample solution, histidine was extracted into the membrane phase and bridged with the Zn(II) center of the porphyrin, causing the monomer porphyrin to be converted to its dimeric species. Since the formation of porphyrin dimer was accompanied by the enhancement of pyrene excimer emission at 454 nm, the chemical recognition process could be directly translated into a fluorescent signal. With the optode membrane M1 described, histidine in sample solution from 6.76 x 10(-7) to 5.01 x 10(-3) M can be determined. The limit of detection was 1.34 x 10(-7) M. The optical selectivity coefficient obtained for histidine over biologically relevant amino acids and anions met the selectivity requirements for the determination of histidine in biological samples. Serum histidine values obtained by the optode membrane fell in the normal range of the content reported in the literature and were in good agreement with those obtained by HPLC.

Amino Acids↗
PubMed2004

Electrochemical impedance behavior of DNA biosensor based on colloidal Ag and bilayer two-dimensional sol-gel as matrices.

A novel method for fabrication of DNA biosensors has been developed by means of self-assembling colloidal Ag (Ag) to a thiol-containing sol-gel network. The thiol groups of 3-mercaptopropyltrimethoxysilane (MPTS) serve as binding sites for the covalent attachment to gold electrode surface. Then the one-dimensional network of silane unites (1dMPTS) was combined together into a two-dimensional sol-gel network (2dMPTS) by dipping into aqueous NaOH. The second silane layer (B2dMPTS) was formed by immersing electrodes back into the MPTS solution overnight, and then the Ag nanoparticles were chemisorbed onto the thiol groups of the second silane layer. Finally, the mercapto oligonucleotide was self-assembled onto the surface via the Ag nanoparticles. The modified process was characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). In addition, we utilized the impedance spectroscopy as a platform for DNA sensing assay. The factors influencing the performance of the resulting biosensor were studied in detail. The linear range of the biosensor was from 8.0 x 10(-9) to 1.0 x 10(-6) M with a detection limit of 4.0 x 10(-9) M at 3sigma. In addition, the experiment results indicate that oligonucleotide immobilized on this way exhibits a good sensitivity and selectivity, high stability and a long-term maintenance of bioactivity.

Binding Sites↗
PubMed2004

The nuclear receptor coactivator AIB1 mediates insulin-like growth factor I-induced phenotypic changes in human breast cancer cells.

The nuclear receptor coactivator AIB1 (amplified in breast cancer 1) is overexpressed in human breast cancers and is required for estrogen signaling. However, the role of AIB1 in breast cancer etiology is not known. Here, we show that AIB1 is rate-limiting for insulin-like growth factor I (IGF-I)-dependent phenotypic changes and gene expression in human breast cancer cells. Reduction of endogenous AIB1 levels by small interfering RNA in MCF-7 breast cancer cells prevented IGF-I-stimulated anchorage-independent growth by reducing IGF-I-dependent anti-anoikis. cDNA array and immunoblot analysis of gene expression revealed that reduction in AIB1 levels led to a significant decrease in the expression of several genes controlling the cell cycle and apoptosis. These AIB1-dependent changes were also observed in the presence of estrogen antagonist and were corroborated in the estrogen receptor-negative cell line MDA MB-231. AIB1 reduction decreased the expression of the IGF-I receptor and IRS-1 in MCF-7 but not in MDA MB-231 cells. IGF-I-stimulated activation of AKT was reduced by AIB1 small interfering RNA treatment, whereas mitogen-activated protein kinase (extracellular signal-regulated kinase 1/2) activation by IGF-I was unaffected. We conclude that AIB1 is required for IGF-I-induced proliferation, signaling, cell survival, and gene expression in human breast cancer cells, independent of its role in estrogen receptor signaling.

Base Sequence↗
PubMed2004

Rat kinesin light chain 3 associates with spermatid mitochondria.

We recently discovered that in rat spermatids, kinesin light chain KLC3 can associate with outer dense fibers, major sperm tail components, and accumulates in the sperm midpiece. Here, we show that mitochondria isolated from rat-elongating spermatids have bound KLC3. Immunoelectron microscopy indicates that the association of KLC3 with mitochondria coincides with the stage in spermatogenesis when mitochondria move from the plasma membrane to the developing midpiece. KLC3 is able to bind in vitro to mitochondria from spermatids as well as somatic cells employing a conserved kinesin light chain motif, the tetratrico-peptide repeats. Expression of KLC3 in fibroblasts results in formation of large KLC3 clusters close to the nucleus, which also contain mitochondria: no other organelles were present in these clusters. Mitochondria are not present in KLC3 clusters after deletion of KLC3's tetratrico-peptide repeats. Our results indicate that the rat spermatid kinesin light chain KLC3 can associate with mitochondria.

Amino Acid Sequence↗
PubMed2004

Progressive loss of Syk and abnormal proliferation in breast cancer cells.

The tumor suppressor gene Syk tyrosine kinase is absent or reduced in invasive breast cancer tissues and cell lines; its loss in breast tissues is linked to poor prognosis and metastasis. Also, evidence shows that in vitro Syk is involved in regulating proliferation. Here, we show by in situ hybridization on breast tissue sections that the loss of Syk expression is progressive during tumor development. Strikingly, Syk is already partially lost in normal epithelial tissue adjacent to the cancer lesion. In vivo, cell proliferation (as measured by the proliferative index Ki67) increased from normal to ductal carcinoma in situ to invasive, whereas Syk in situ staining in the same tissues decreased. In vitro, the presence of Syk was associated with reduced cell proliferation in an epidermal growth factor receptor-overexpressing breast cancer cell line, BT549, whereas changes in apoptosis were undetected. Concomitantly, the kinase activity of the proto-oncogene Src was reduced by approximately 30%. A 5-fold increase in abnormal mitoses was observed in the Syk-transfected cells compared with vector control. We propose that Syk is involved in the regulation of cell proliferation, possibly by controlling mechanisms of mitosis and cytokinesis via Src signal transduction pathway(s). Because of its progressive and early loss during tumor onset and development, monitoring of Syk loss in breast epithelial cells by noninvasive techniques such as ductal lavage may be a powerful tool for screening purposes.

Apoptosis↗
PubMed2004

Selection of active ScFv to G-protein-coupled receptor CCR5 using surface antigen-mimicking peptides.

This study describes the use of cyclic peptides for use in the selection of single-chain (ScFv) antibodies specific for the HIV-1 coreceptor CCR5, a representative G-protein-coupled receptor (GPCR). A tandem ligation strategy was developed for preparing biotinylated cyclic peptides, first through an orthogonal end-to-end ligation and then a chemoselective ligation with functionalized biotin. Cyclic peptides mimicking the extracellular loops of CCR5 and their unconstrained counterparts were then used for solution-phase selection of ScFv antibodies from a phage display antibody library. Antibodies reactive with CCR5 on cells were detected using a homogeneous high throughput assay. Of 19 isolated ScFv antibodies that bound to CCR5+ cells, three inhibited CCR5-mediated but not CXCR4-mediated HIV infection. Only ScFvs selected by binding to cyclic constrained peptides exhibited inhibitory activity. Our results demonstrate that surface-antigen mimetics of a GPCR are effective tools for selecting active, site-specific ScFv antibodies that hold promise as immunological reagents and therapeutics.

Amino Acid Sequence↗
PubMed2004

[Distribution of IgG subclass of anti-myeloperoxidase antibodies in sera from patients with propylthiouracil induced vasculitis].

OBJECTIVE: To investigate the distribution of IgG subclass of anti-myeloperoxidase (MPO) antibodies, a kind of antineutrophil cytoplasmic autoantibody (ANCA), in sera from patients with propylthiouracil (PIU)-induced vasculitis. METHODS: Serum samples were collected from 12 patients with PIU-induced MPO ANCA positive vasculitis, both sera of active and remission phases were collected from 10 of which, and only serum of active phase was collected from 2 of which. Anti-MPO IgG subclasses were detected by antigen-specific ELISA. The distribution of anti-MPO IgG subclasses in PIU-induced vasculitis was compared with that in primary vasculitis. RESULTS: Anti-MPO IgG3 subclass was not detected in the sera from both active and remission phases of PIU-induced vasculitis. In the active phase the following anti-MPO IgG subclasses were found: IgG1 (12/12, 100%), IgG2 (1/12, 66.7%), and IgG4 (7/12, 58.3%). In the remission phase, the following anti-MPO IgG subclasses were found: IgG1 (9/10, 90%), IgG2 (4/10, 40%), and IgG4 (2/10, 20%). The titer of anti-MPO IgG4 subclass remained high in the remission phase in primary vasculitis; however, it decreased significantly after the cessation of PIU use in PIU-induced vasculitis. CONCLUSION: The distribution of anti-MPO IgG subclasses in the sera of the patients with PIU-induced vasculitis is different from that of the patients with primary vasculitis. The higher titer pf MPO-ANCA in the sera of the patients with PIU-induced vasculitis may be associated with the repeated PIU stimulation.

Adolescent↗
PubMed2004

Anticancer activity and mechanism of Scutellaria barbata extract on human lung cancer cell line A549.

Scutellaria barbata (S. barbata), a traditional Chinese herbal medicine native to southern China, is widely used as an anti-inflammatory and a diuretic in China. Several studies have indicated that extracts of S. barbata have growth inhibitory effects on a number of human cancers. Treatment of lung cancer, digestive system cancers, hepatoma, breast cancer, and chorioepithelioma by S. barbata extracts was reported. However, the mechanism underlying the antitumor activity was unclear. In this study, we studied the growth inhibitory effect of S. barbata and determined its mechanism of antitumor activity using human lung cancer cell line A549. Our results showed that ethanol extracts of S. barbata greatly inhibited A549 cell growth, with IC50 of 0.21 mg/ml. The major mechanisms of inhibition included cell apoptosis and cytotoxic effects. cDNA microarray analysis showed that 16 genes, involved in DNA damage, cell cycle control, nucleic acid binding and protein phosphorylation, underwent more than 5-fold change. These data indicated that these processes are involved in S. barbata-mediated killing of cancer cells. A surprising finding is that CD209, related to dendritic cell (DC) function, was dramatically downregulated by 102-fold. Further functional studies are needed to assess the role of the array-identified genes in S. barbata mediated anticancer activity.

Annexin A5↗
PubMed2004

PEGylation confers greatly extended half-life and attenuated immunogenicity to recombinant methioninase in primates.

Methionine depletion by recombinant methioninase (rMETase) has been demonstrated previously to be highly effective in tumor-bearing mouse models. However, the therapeutic potential of rMETase has been limited by its short plasma half-life and immunologic effects, including high antibody production in mice and monkeys and anaphylactic reactions in monkeys. To overcome these limits of rMETase, the enzyme has been coupled to methoxypolyethylene glycol succinimidyl glutarate (MEGC-PEG-5000). In this study, we evaluated the pharmacokinetics, antigenicity and toxicity of MEGC-PEG-rMETase in Macaca fascicularis monkeys using an escalating-dose strategy. Dose ranging studies at 1,000, 4,000, and 8,000 units/kg i.v. determined that a single dose of 4,000 units/kg was sufficient to reduce plasma methionine to <5 micromol/L for 12 hours. Pharmacokinetic analysis with the single 4,000 units/kg dose showed that MEGC-PEG-rMETase holoenzyme activity was eliminated with a biological half-life of 1.3 hours, and the MEGC-PEG-rMETase apoenzyme was eliminated with a biological half-life of 90 hours, an approximately 36-fold increase compared with non-PEGylated rMETase. A single dose at 2,000 units/kg of MEGC-PEG-rMETase resulted in an apoenzyme half-life of 143 hours. A seven-day i.v. administration of 4,000 units/kg every 12 hours resulted in a steady-state depletion of plasma methionine to <5 micromol/L. The only manifest toxicity was decreased food intake and slight weight loss. Red cell values and hemoglobin declined transiently during treatment but recovered after cessation of treatment. Subsequent challenges on days 29, 50 and, 71 did not result in any immunologic reactions. This result is in contrast to non-PEGylated rMETase, which elicited anaphylactic reactions in monkeys. Anti-MEGC-PEG-rMETase antibodies (at 10(-2)) were found on day 29, and these increased to 10(-3) to 10(4) on day 71, 100 to 1,000-fold less than antibodies elicited by naked rMETase. Although anti-MEGC-PEG-rMETase antibodies were produced, no neutralizing antibody was identified, and each challenge dose was effective in depleting plasma methionine levels. The results of the present study demonstrate that PEGylation greatly prolongs serum half-life of the rMETase apoenzyme and eliminated anaphylactic reactions. The results indicate a profile with respect to serum half-life, toxicity, and antigenicity that suggest clinical potential of MEGC-PEG-rMETase.

Animals↗