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Biomedical subjects

Ying Zhu

Publications and source records attributed to Ying Zhu.

At least 91 records · Page 5Linked to original sources
PubMed2004

Targeted liposomal drug delivery in cancer.

Liposomes, which are biodegradable and essentially non-toxic vehicles, can encapsulate both hydrophilic and hydrophobic materials, and are utilized as drug carriers in drug delivery systems. In addition, liposomes can be used to carry radioactive compounds as radiotracers can be linked to multiple locations in liposomes. One option is the hydrated compartment inside the liposome, another the lipid core into which especially hydrophobic conjugates can be attached, and the third option is the outer lipid leaflet where molecules can be bound by covalent linkage. Delivery of agents to the reticuloendothelial system (RES) is easily achieved, since most conventional liposomes are trapped by the RES. For the purpose of delivery of agents to target organs other than RES, long-circulating liposomes have been developed by modifying the liposomal surface. Understanding of the in vivo dynamics of liposome-carried agents is required for the evaluation of the bioavailability of drugs encapsulated in liposomes. In this review, we focus on the in vivo trafficking of liposomes visualized by positron emission tomography (PET) and discuss the characteristics of liposomes that affect the targeting of drugs in vivo.

Animals↗
PubMed2004

Lipid analyses for the management of vascular diseases.

Despite a long history of studies on lipid abnormalities, numerous problems in laboratory technologies and techniques remain unresolved. One of the most commonly tested molecules is low-density lipoprotein (LDL) cholesterol, and a homogenous assay technique for measurement of this molecule has recently been introduced. Although the method represents remarkable technological breakthroughs with great potential for improving lipoprotein analysis, some discrepancies exist among assay protocols. Even for direct measurement of high-density lipoprotein (HDL) cholesterol, which has widely been accepted, there are still large discrepancies among data obtained by different protocols. Oxidatively modified LDL is an independent factor that is considered to directly contribute to the pathogenesis of early atherosclerosis. Lipid peroxidation products, surface charge, and spectrophotometric patterns are all applicable to the evaluation of in vitro oxidation. Only enzyme-linked immunosorbent assays using monoclonal antibodies have a potential for clinical use, but such methods are not yet standardized. There is also increasing evidence for the presence of anti-oxidized LDL autoantibodies in human sera, but the diagnostic utility remains controversial. In addition, small dense LDL has recently attracted much attention as an independent risk factor. Although this is a potential target of oxidization, a robust and simple analytical method does not yet exist. This review presents the current state of laboratory technologies for testing lipid abnormalities.

Animals↗
PubMed2004

[Effect of bushen ningxin decoction on proliferation and apoptosis of murine osteoblast].

OBJECTIVE: To investigate the effect of Bushen Ningxin decoction (BSNXD) on postmenopausal osteoporosis. METHODS: Postmenopausal osteoporosis model of female BALB/c mice were founded and afforded with BSNXD. The experiment was ceased, and the skeleton and blood of mice in each group were collected following 12 weeks of the treatment. Change of osteoblastic organelle in right femur was observed by transmission electron microscope (TEM). Osteoblasts from calvaria of different groups were isolated and cultured by the tissue fragment migrating growth method and the proliferation ratio of osteoblasts in the second passage was examined with thiazolyl blue reagents when cultured for 1 day and 5 days, respectively. RESULTS: TEM showed that the osteoblasts of the animal treated by BSNXD had more cell organelles and developed Golgi complex, whose ability of proliferation(P < 0.05) and anti-apoptosis is stronger than that of OVX group. CONCLUSION: BSNXD can accelerate the proliferation and inhibit the apoptosis of osteoblasts, the effective concentration of pharmacological serum varies from 10% to 20%.

Animals↗
PubMed2004

[Inducing peripheral materno-fetal immuno-tolerance by blockade of costimulatory signal at early stage of gestation of the abortion-prone murine model].

OBJECTIVE: To study effect of blockade of costimulatory signal CD(80), CD(86) at the early stage of gestation on the maternal peripheral immuno-tolerance status to paternal antigen and pregnant outcome of murine abortion-prone model. METHODS: The experiments were performed in two groups, using CBA/J x BALB/c matings as the normal pregnancy model and CBA/J x DBA/2 matings as the abortion-prone model. The pregnant CBA/J mice which had mated with DBA/2 or BALB/c male mice respectively were injected intraperitoneally with purified rat isotype IgG or purified rat anti-mouse CD(80), CD(86) mAb at day 4 of gestation (time of implantation). The proliferation response of maternal splenic immuno-competent cells to paternal splenic cells as stimulator was analyzed by one way mixed lymphocyte reaction, and IL-2 production was assayed by ELISA to evaluate the immuno-tolerance of maternal peripheral immuno-competent cells to paternal antigen at day 9 of gestation. The embryo resorption rate was counted at day 14 of gestation. RESULTS: In the CBA/J x DBA/2 matings, anti-CD(80), CD(86) mAb administered at day 4 of gestation reduced significantly the embryo resorption rate, and induced a significantly lower proliferation response and IL-2 production by maternal splenic immuno-competent cells to paternal antigen compared with rat isotype IgG. CONCLUSIONS: In vivo blockade of costimulatory signal at day 4 of gestation can induce the immuno-tolerance of maternal peripheral immuno-competent cells to paternal antigen, thus leading the embryo resorption rate of the abortion-prone model to that of normal pregnancy model.

Abortion, Spontaneous↗
PubMed2004

Absolute configuration of chloro-bisabolene sesquiterpene.

The crystal structure of a cholor-bisabolene sesquiterpene has been determined for the absolute configuration. Its structure was elucidated as (-)-(1R,2R,3R,4R,6S,8S,10S)-chloro-2,10-diacetoxy-1,8-diangeloyloxy-3-hydroxy-11-methoxy-bisabol-7(14)-ene. The chlorine atom at C4 is axial in the cyclohexane ring. The molecule shows a stable chair conformation, and crystallizes in the monoclinic space group P2(1) with one molecule in the asymmetric unit.

Antineoplastic Agents, Phytogenic↗
PubMed2004

[Protective effect of bushen ningxin recipe on ovariectomized rabbits with atherosclerosis].

OBJECTIVE: To study the effects of Bushen Ningxin recipe (BNR) on atherosclerosis in ovariectomized rabbits. METHODS: Twenty-six female New Zealand white rabbits of three months old were randomly divided into four groups, the normal group, the sham operation group, the control group (ovariectomized) and the treated group (ovariectomized and treated with BNR). All rabbits, except the normal group, were fed with high-cholesterol diet starting from two weeks after operation, and to the treated group BNR was given additionally for 3 months. Levels of blood lipid (TC, TG, LDL-C and HDL-C) and NO were measured at the end of the 12th week, and at the same time, histomorphological and pathological examination of aorta under light microscopy and scanning electron microscopy, and the ratio of atherosclerotic area of lesion/endothelium ratio (AL/AE) and thickness of endothelium/medium ratio (TE/TM) were estimated using image analyzer. RESULTS: No significant difference was found in levels of blood lipid between groups, except those in the normal group. As compared with the control group, in the treated group, level of serum NO was higher, AL/AE and TE/TM were lower and the pathological changes of aorta was milder. CONCLUSION: BNR could inhibit the atherosclerosis formation in ovariectomized rabbits, it showed protection on vascular endothelial cells.

Animals↗
PubMed2004

[Enhancement of immunogenicity of hCGbeta protein vaccine and the hCG neutralization capacity of anti-serum by using the molecular adjuvant C3d3].

To enhance the immunogenicity of hCGbeta protein vaccine and the hCG neutralization capacity of anti-serum by using the molecular adjuvant C3d3, the secreted 6his-hCGbeta-C3d3 fusion protein and 6his-hCGbeta were expressed in CHO cells and purified with Ni(2+)-chelating chromatography and Sephadex G-150 column. Then we investigated the potential of three copies of C3d as the molecular adjuvant of hCGbeta protein antigen. The antibody response to hCGbeta-C3d3 conjugates was compared with those resulting from immunization with hCGbeta alone and hCGbeta plus CFA/IFA in BALB/c mice. Our results showed that the antibody titer of hCGbeta-C3d3 was 1995-fold higher than that of hCGbeta alone and the anti-serum was capable effectively neutralizing the bioactivity of hCG. The immunity-enhancing action of C3d3 was 10-fold (primer) and 32-fold (booster) greater than CFA/IFA. These results indicated that C3d3 conjugates might be a better way to overcome the poor immunogenicity of hCGbeta contraceptive vaccine.

Adjuvants, Immunologic↗
PubMed2004

[The recurrent nasal polyp analysed by mRNA difference to demonstrate].

OBJECTIVE: To look for the correlated gene of nasal polyp. METHOD: The nasal polyp was analysed by mRNA difference to demonstrate, and the fragment of writing was analysed and appraised. RESULT: The amplification products of normal conchae tissue were compared with the nasal polyp tissue under the condition of background with one accord. The total 11 difference fragments were discovered during the 150-700 bp. One of the fragments (X-1) was completely homology with the section series of the eight chromosome long arm. There was a zine finger protein in the upper stream and the down stream. The fragment expressed in nasal polyp tissue. CONCLUSION: Based on polymerase chain reaction (pcr), using differential display R. T. PCR (DD-RTPCR) technique, the difference express gene of nasal polyp could be effectively compared with normal nasal conchae tissue or cells, the correlated gene of nasal polyp tissue could screened out. The fragment (X-1) that was completely homology with the section series of the eight chromosome long arm may be a new identified gene which cause the nasal polyp.

Adult↗
PubMed2003

[Roles of intracellular calcium and monomeric G-proteins in regulating exocytosis of human neutrophils].

Neutrophils play a major role in host defense against microbial infection. There are some clues indicate that neutrophils may also play a role in the pathophysiology of the airway obstruction in chronic asthma. We studied the roles of intracellular calcium and GTP gamma S in the regulation of neutrophils exocytosis using pipette perfusion and membrane capacitance measurement technique in whole cell patch clamp configuration. The results showed that the membrane capacitance increase induced by calcium revealed a biphasic process. The first phase occurred when the calcium level was between 0.2-14 micromol/L with a plateau amplitude of 1.23 pF and a calcium EC50 of 1.1 micromol/L. This phase might correspond to the release of the tertiary granules. The second phase occurred when the calcium concentration was between 20-70 micromol/L with a plateau increment of 6.36 pF, the calcium EC50 being about 33 micromol/L. This phase might represent the release of the primary and secondary granules. Intracellular calcium also simultaneously increased the exocytotic rate and the eventual extent in neutrophils. On the other hand, GTP gamma S can increase the exocytotic rate in a dose-dependent manner but had no effect on the eventual extent of membrane capacitance increment (>6 pF) if the cell was stimulated for a long period (>20 min). GTP gamma S (ranging from 20 to 100 micromol/L) induced the neutrophils to release all four types of the granules at very low intracellular calcium level.

Calcium↗
PubMed2003

Quantitative analysis of binding of transcription factor complex to biotinylated DNA probe by a streptavidin-agarose pulldown assay.

Gene expression is regulated by a large complex of proteins that bind to the promoter/enhancer region of a gene. We determined whether a streptavidin-bead binding assay might be useful in detecting individual proteins in the complex comprising transactivators, coactivators, mediators, and general transcription factors. We used biotinylated cyclooxygenase-2 promoter probes as a model. Nuclear extracts obtained from human fibroblasts treated with or without an agonist were incubated with a 5(')-biotinylated probe and streptavidin-agarose beads at room temperature for 1h. After centrifugation, the pellet was washed and proteins in the complex were assessed by immunoblots. An array of transcription factors was detectable concurrently in the same batch of pellets at basal state. p300 and its associated factor PCAF levels but not Srb7, Med7, or TFII(B) were increased by phorbol ester or tumor necrosis factor alpha stimulation. Only trace of CREB-binding protein was detected. These results suggest that p300 and PCAF are the predominant coactivators for COX-2 promoter activation. Our findings indicate that the streptavidin-bead pulldown assay is valuable for determining the binding of a large number of transcription factors to promoter/enhancer and evaluating the relationship of protein binding with regulation of gene expression.

Bacterial Proteins↗
PubMed2003

Role of p300 and PCAF in regulating cyclooxygenase-2 promoter activation by inflammatory mediators.

Coactivators p300 and CREB (cyclic adenosine monophosphate [cAMP]-response element binding protein)-binding protein (CBP) serve as an integrator for gene transcription. Their relative involvement in regulating cyclooxygenase-2 (COX-2) promoter activity had not been characterized. Using fibroblast and macrophage COX-2 transcription as a model, we determined p300 and CBP levels in nuclear extracts and their binding to a COX-2 promoter probe. CBP level was barely detectable and there was little CBP binding. In contrast, p300 was detectable in nucleus and its binding to a COX-2 promoter probe was enhanced by phorbol 12-myristate 13-acetate (PMA), interleukin-1 beta(IL-1 beta), or lipopolysaccharide (LPS). Binding of p300/CBP-associated factor (PCAF) was also up-regulated. COX-2 proteins and promoter activities induced by these agonists were augmented by p300 overexpression. Early region 1A (E1A), but not its deletion mutant, abrogated COX-2 expression induced by inflammatory mediators and with or without p300 overexpression. Molecular analysis of p300 revealed the requirement of multiple domains, including histone acetyltransferase (HAT) for COX-2 transactivation. Furthermore, roscovitine, an indirect inhibitor of p300 HAT, and histone deacetylase-1 transfection completely abolished COX-2 promoter activity. We conclude that p300 is the predominant coactivator that is essential for COX-2 transcriptional activation by proinflammatory mediators.

Adenovirus E1A Proteins↗
PubMed2003

An interaction between a MYC protein and an EREBP protein is involved in transcriptional regulation of the rice Wx gene.

We previously demonstrated that a 31-bp nucleotide sequence located upstream of the rice Wx gene played an important role in its expression. We further showed that this cis-acting regulator interacts with nuclear proteins extracted from developing rice endosperm. We used the 31-bp sequence as bait in a yeast one-hybrid system to isolate several cDNA clones from a rice cDNA expression library. One of these cDNAs encodes a MYC protein, designated OsBP-5, which is 335 amino acids long and contains a putative basic helix-loop-helix-ZIP DNA-binding domain. This domain exhibits 50% amino acid sequence identity with the R/B proteins that regulate the expression of genes involved in anthocyanin biosynthesis in plants. The results of electrophoretic mobility shift assays (EMSAs) and Southwestern gel blots indicate that this protein binds specifically to the CAACGTG motif within the 31-bp sequence. However, by itself, the OsBP-5 protein is unable to trans-activate a lacZ reporter gene controlled by the 31-bp sequence when tested in a yeast expression system. Interestingly, OsBP-5 can trans-activate this reporter gene when another protein, OsEBP-89, a member of the EREBP family of transcription factors, is present. Furthermore, in vitro pull-down experiments show that a protein isolated from developing rice endosperm interacts with the OsBP-5 protein, and Western blots confirm that the interacting protein is OsEBP-89. The formation of a supershift band in EMSAs also indicates that two proteins interact with each other. Interference of OsBP-5 gene expression by double-stranded RNA reduces the amylose content in mature seed of transgenic rice plants but has no visible effect on their phenotype. These results suggest that the OsBP-5 and OsEBP-89 proteins act synergistically, perhaps as a heterodimer, to regulate the transcription of the rice Wx gene.

Amino Acid Motifs↗
PubMed2003

Gene fusion of molecular adjuvant C3d to hCGbeta enhances the anti-hCGbeta antibody response in DNA immunization.

OBJECTIVE: To express the hCGbeta-C3d3 fusion protein in a CHO cell continual expression system to investigate further the adjuvant effects of C3d on contraceptive vaccination. METHOD: We constructed a plasmid pcDNA3-hCGbeta-C3d3 which contains three copies of murine C3d cDNA and the hCGbeta gene by cloning the chimerical hCGbeta-C3d3 cDNA into the eukaryotic vector pcDNA3 downstream of the CMV promoter. The plasmid was transfected into a COS-7 cell transient expression system and a CHO cell continual expression system. RIA was used to detect hCGbeta in the culture supernatant. Western blot and Raji cell immunohistochemical assays were performed to evaluate the expressed protein. Then, 6-8-week-old female BALB/c mice were inoculated intramuscularly with pcDNA3-hCGbeta and pcDNA3-hCGbeta-C3d3, and ELISA was used to assess anti-hCGbeta IgG antibody in serum. RESULTS: In 72 h after COS-7 cells were transfected with the plasmid pcDNA3-hCGbeta-C3d3, 1.0x10(5) cells could secrete 152 ng of the recombinant protein (calculated by hCGbeta contained). The transfected CHO cells, which were then screened by G418, could continuously secrete the fusion protein at 660 ng/10(6) cells/48 h. The hCGbeta-C3d3 protein was purified by anti-hCGbeta immunoaffinity chromatography. Raji cell immunohistochemical assay demonstrated that both the hCGbeta and C3d3 were successfully fused. After DNA immunization intramuscularly, the anti-hCGbeta IgG antibody titer in the pcDNA3-hCGbeta-C3d3 immunized group was 243-fold higher than that of the pcDNA3-hCGbeta immunized group. CONCLUSION: We have expressed the hCGbeta-C3d3 protein successfully, both in a transient expression system (COS-7 cells) and in a stable expression system (CHO cells). The C3d3 molecular adjuvant can enhance significantly the immunogenecity of hCGbeta antigen in DNA immunization.

Animals↗
PubMed2003

Functional study on baculovirus anti-apoptosis genes.

Apoptosis of bollworm cell line Hz-AM1 can be delayed by transient expression of AcNPV (Autographa californica Nuclear Polihedrosis Virus) p35 gene. Acp35Z, a p35 inactivated AcNPV by inserting with LacZ gene, cannot replicate in Hz-AM1 cells. However, the replication can be rescued by co-transfection with a plasmid containing AcNPV p35 gene. It is also realized that the transient expression of AcNPV p35 gene in Hela cells can put off cell apoptosis which is induced by adding actinomycin-D. Through co-transfection and G418 screening, two anti-apoptosis cell lines named Sf9-35 and Vero-35 are established by integrating AcNPV p35 and Neo expression cassette into the cell chromosomes. The Sf9-35 enhances the yield of budded virus of AcNPV, while the Vero-35 increases the propagation of measles virus.

Animals↗
PubMed2003

Abnormal expression of apoptosis-related genes in haematological malignancies: overexpression of MYC is poor prognostic sign in mantle cell lymphoma.

The expression of apoptosis-related genes BCL2, BAX, BCL2L1, BCL2A1, MCL1, DAPK1 and MYC was studied by quantitative real-time polymerase chain reaction on total RNA samples from patients with acute lymphoblastic leukaemia (ALL, n = 16), acute myeloid leukaemia (AML, n = 27), chronic myeloid leukaemia (CML, n = 12), mantle cell lymphoma (MCL, n = 19) and chronic lymphoid leukaemia (CLL, n = 32). BCL2, BAX, BCL2A1, MCL1, DAPK1 and MYC were overexpressed in all patient groups. BCL2L1 was underexpressed in CLL and CML, but not in AML, ALL and MCL. MCL1 levels were significantly higher in CD13 and CD33-positive ALL, and in CD56-positive AML samples. BCL2, BCL2L1, BCL2A1 and MCL1 were overexpressed and DAPK1 was underexpressed in CLL samples with a 11q23 deletion. MYC overexpression was significantly associated with shorter overall survival in MCL (P < 0.01). AML patients with a normal karyotype showed a higher frequency of BCL2A1 overexpression (P < 0.001) than those with an abnormal karyotype.

Adult↗
PubMed2003

Comparison of comet assay, electron microscopy, and flow cytometry for detection of apoptosis.

Differentiating apoptosis from necrosis is a challenge in single cells and in parenchymal tissues. The techniques available, including in situ TUNEL (Terminal deoxyribonucleotide transferase-mediated dUTP-X Nick End-Labeling) staining, DNA ladder assay, and flow cytometry, suffer from low sensitivity or from a high false-positive rate. This study, using a Jurkat cell model, initially evaluated the specificity of the neutral comet assay and flow cytometry compared to the gold standard, electron microscopy, for detection of apoptosis and necrosis. Neutral comet assay distinguished apoptosis from necrosis in Jurkat cells, as evidenced by the increased comet score in apoptotic cells and the almost zero comet score in necrotic cells. These findings were consistent with those of electron microscopy and flow cytometry. Furthermore, using rats with burn or ischemia/reperfusion injury, well-established models of skeletal and cardiac muscle tissue apoptosis, respectively, we applied the comet assay to detect apoptosis in these muscles. Neutral comet assay was able to detect apoptotic changes in both models. In the muscle samples from rats with burn or ischemia-reperfusion injury, the comet score was higher than that of muscle samples from their respective controls. These studies confirm the consistency of the comet assay for detection of apoptosis in single cells and provide evidence for its applicability as an additional method to detect apoptosis in parenchymal cells.

Animals↗
PubMed2003

[Determination of chlorhexidine acetate in disinfectant by high performance liquid chromatography].

A high performance liquid chromatography(HPLC) was described for the determination of chlorhexidine acetate in disinfectant on a C18 column using acetonitrile-0.02 mol/L potassium dihydrogen phosphate solution(pH2.5) (40:60) as mobile phase. The regression equation was linear when the chlorhexidine acetate concentration was lower than 1.00 g/L. The detection limit was 8 mg/L. The precision was less than 4.0% and the recovery varied from 99.8% to 115.2%. The method was more sensitive, rapid and simple than other HPLC methods, and the characteristic of low disturbance makes it especially important for the assay of chlorhexidine acetate in compound disinfectant comparing with titrimetry and UV spectrophotometry.

Chlorhexidine↗