Biomedical subjects

C Wu

Publications and source records attributed to C Wu.

At least 271 records · Page 15Linked to original sources

PubMed1999

[The intracellular signaling pathway initiated by ginsenosides in hematopoietic cells].

OBJECTIVE: To investigate that ginsenosides (GS) promotes proliferation of hematopoietic cells by virtue of the intracellular signaling pathway. METHODS: Three human megakaryocytic cell lines and Northern blot analysis, electrophoretic mobility shift assay (EMSA), antibody gel supershift assay and UV-radiation cross-linking were used. RESULTS: After treatment with GS, GATA-2 mRNA levels in CHRH-288, Meg-01 and MO7e cells were increased by 1.84-, 2.43- and 1.52-fold, respectively, while GATA-1 mRNA levels remained as low as pretreatment. GATA binding activities were elevated in all the three GS treated cell lines. The GATA binding complex appeared as a band with an approximate molecular weight of 50,000 corresponding to the size of GATA-2 protein. CONCLUSIONS: The intracellular signaling pathway initiated by GS was involved in transcription factor GATA-2. GATA-2 might play the key role in the GS induced upregulation of megakaryopoiesis.

Cell Line↗

PubMed1999

[Detection of human immunodeficiency virus infection in tuberculosis patients].

OBJECTIVE: Combined infection of human immunodeficiency virus (HIV) and Mycobacterium tuberculosis (MTB) has attracted wide attention. This study was to find out infection of HIV and occurrence of AIDS in tuberculosis patients. METHODS: Primary screening was conducted in 2 973 inpatients with pulmonary tuberculosis by gelatin particle agglutination assay or rapid gold-labeled HIV 1 + 2 antibody assay. The HIV positive cases were sent to Beijing Municipal Center Laboratory for verification. RESULTS: Three HIV positive cases were detected among 2,973 pulmonary tuberculosis patients with the positive rate of 1.01 per thousand. Two were male and 1 female with average age of 30 years (23, 27, and 40 years respectively) accounting for 2.86 per thousand of the 21 - 41 age group, among which 1 infected through intravenous drug injection, 2 by heterosexual behavior. And all the 3 HIV positive cases had developed to be AIDS. CONCLUSIONS: Enough knowledge of the risk of combined HIV/MTB infection and high-degree alert should be emphasized in medical professionals involving in diagnosis, treatment and management of tuberculosis. Routine HIV antibody detection in high-risk tuberculosis patients for HIV infection, especially in young and middle-age tuberculosis patients, is helpful for early diagnosis and treatment of AIDS and avoiding its spreading.

Adult↗

PubMed1999

[Multiple inhibitory mechanisms of wild-type p16 gene transfer into human bladder cells by retroviral vector].

OBJECTIVE: To investigate the inhibitory mechanisms of wild-type p16 gene transfer into human bladder cancer cells with or without endogenous p16 gene expression. METHODS: p16 recombinant retrovirus vector was constructed and transfected in human bladder cancer cell EJ and 253J. Northern blot analysis and immunocytochemistry were used to detect the expression of exogenous p16 gene. Flow cytometry analysis was used to detect tumor cell cycle. Electronic microscope and in situ labelling apoptotic DNA fragment detection (TUNEL) was used to detect tumor cell apoptosis after gene transfection. Tumorigenicity was observed in nude mice. RESULTS: The growth rate of the transfected EJ cells was significantly retarded, the majority of transfected EJ cells were arrested on G(0) + G(1) phases of cell cycle, tumorigenicity of the transfected cells was reduced on nude mice. H-ras gene expression in transfected EJ cells reduced as compared with non-transfection. Apoptotic cells were observed in transgenic 253J cells. CONCLUSIONS: Malignant proliferation of bladder cancer cells can be inhibited by exogenous p16 gene transfection via different molecular pathway.

Animals↗

PubMed1999

[The mechanism of p16 gene inactivation in human bladder transitional cell carcinoma].

OBJECTIVE: To figure out the mechanism of p16 gene inactivation in human bladder transitional cell carcinoma (BTCC). METHODS: p16 gene was analyzed for genetic alterations by Southern blot analysis, PCR-SSCP and DNA methylation analysis in 52 cases of transitional cell carcinoma of bladder. RESULTS: p16 gene deletion was found in 11 of 52 (21.15%) BTCCs, only one tumor showed point mutation on p16 exon 2, nineteen cases of BTCCs (36.53%) showed p16 gene 5' CpG island methylation. CONCLUSION: There was a statistically significant association between p16 gene deletion and early stage, well differentiated tumors. Additionally, a statistically significant correlation was also noticed between p16 gene 5' CpG island methylation and tumors in late stage with poor cell differentiation.

Blotting, Southern↗

PubMed1999

[Study on anticardiolipin antibody in the patients with primary nephrotic syndrome].

Combination of the anticardiolipin antibody with the phospholipids on the surfaces of the endothelia and thrombocytes can damage the basic functions of cells. In this study, the anticardiolipin antibody was detected in 68 cases with primary nephrotic syndrome and 30 healthy persons. The positive rates were 32.35% and 3.33%, respectively. The hypercoagulability and glomerular impairment in the positive cases were more evident than those in the negative cases. In addition, the sensitivity to treatment in the positive cases was markedly decreased. These findings indicate that the anticardiolipin antibody may play an important role in pathophysiological processes of primary nephrotic syndrome.

Adolescent↗

PubMed1999

[Research of polymer coating in solid phase microextraction].

The solid phase microextraction (SPME) is a new extraction technique which has been developed rapidly in 1990s. It is a fast, simple, solventless and sensitive method for analyzing environmental samples. However, the solid phase materials of SPME are relatively limited. This paper presents the research work on a new type of solid phase, polymethylvinylsiloxane (PMVS), used in SPME. The phase with 1% vinyl content could be used in light curing. The PMVS solution was coated on the surface of silica fiber and was quickly cured by UV. Two fibers with 87 microns and 44 microns thick PMVS coatings were prepared. They were compared with commercial polymer coating SPME fibers through Headspace SPME Gas Chromatograph (HS-SPME-GC). The adsorption and desorption kinetics of PMVS were studied. The HS-SPME system was optimized and the differences between HS-SPME and HS were investigated as well. The results indicated that PMVS is efficient in extracting volatile and semi-volatile organic compounds and PMVS showed the high thermostability and easy-coating properties. The detection limit of SPME using 88 microns PMVS coating was about 1-5 micrograms/L.

English Abstract↗

PubMed1999

[Expression and significance of neuropeptide and neurotensin in the extract of platelet of chronic renal failure patients during hemodialysis].

The aim of this study was to investigate the change of neuropeptide Y(NPY) content and neurotensin (NT) content of the platelet from chronic renal failure (CRF) patients during hemodialysis (HD) and explore its mechanism of action. Platelet was separated from the patients' plasma and the NPY and and NT contents of the platelet and plasma were dynamically observed pre-HD and post-HD. 30 healthy people were chosen as the controls. The results showed the NPY and NT contents of the platelet extract were (58.18 +/- 21.29) ng/10(9) and (25.38 +/- 13.43) ng/10(9) respectively. The NPY content of the platelet extract of the CRF patients was obviously decreased and the NT content of the plasma was obviously increased however, the NT contents of the platelet extract and the plasma were both higher than those in the control group. The NPY content of the platelet extract and NT content of the plasma at the post-HD obviously increased as compared with pre-HD, but the NT content of the platelet extract and the NPY content of the plasma obviously decreased. There was an obvious correlation between NPY and NT. The authors conclude that during the period of CRF, the immunoreactions which mainly involve bio-active substances such as NPY, NT and 5-hydroxytryptamine released by the platelet to interfer the vasoconstrictive effect are the main pathologic factors to induce renal hypertensin and renal vasospasm.

Adult↗

PubMed1999

[Determination of circulating antigen in urine of rabbits infected with Schistosoma japonicum].

AIM: To develop an immunoassay for the detection of circulating schistosome antigen (CSA) in host urine. METHODS: CSA extracted from the urine of the rabbits infected with Schistosoma japonicum was used for preparing and selecting specific monoclonal antibody. A one-step dot-ELISA using this specific McAb and a 2nd antibody was used for detection of circulating schistosome antigen in the urine of infected rabbits. RESULTS: No CSA was detected in urine from all of 22 rabbits before infection. The positive rate of CSA in infected rabbits was correlated with the intensity of infection and the time of infection. No CSA was detected in the urine rabbits of 3 weeks after infection with 25 cercariae while the positive rate of CSA in the urine from rabbits infected with 200 cercariae was 40% and 100% after 3 and 6 weeks, respectively. A combination of CSA detection in both urine and serum may increase the detectability. CONCLUSION: The specific McAb prepared by urine CSA of Schistosoma japonicum-infected rabbits can be used as a probe for detecting CSA in the urine of infected rabbits.

Animals↗

PubMed1999

[Preparation of monoclonal antibodies by intrasplenic immunization of mice with urine circulating antigen from patients infected with Schistosoma japonicum].

AIM: To explore an efficient method for preparing monoclonal antibodies against circulating antigen of S. japonicum in the urine of schistosomiasis patients. METHODS: The urine of schistosomasis patients were precipitated with 5% trichloroacetic acid, and then used to immunize the BALB/c mice by intrasplenic immunization to prepare McAb. RESULTS: Two monoclonal cell lines against the CAg in the urine of schistosomiasis patients have been established. The immunoglobulin subclass of the 2 McAbs (2E6 and 2B11) were identified as IgM. The titres of 2E6 and 2B11 were 2.56 x 10(5) and 6.4 x 10(4). On immunodiffusion, McAb 2E6 showed one precipitation line with IHU-CAg, however, both McAbs did not react with NHU-CAg. Using ascitic fluid of 2B11 and 2E6 as capture antibody separately, and HRP-H11 as labelled antibody to detect the urine of 12 acute schistosomasis patients, 2B11 2E6 gave 6 and 3 positive, respectively, whereas 8 normal urine were all negative. CONCLUSION: It is feasible to use CAg from schistosomasis patients' urine to prepare anti-CAg McAb by intrasplenic immunization in mice.

Animals↗

PubMed1999

Alpha-emitting bismuth cyclohexylbenzyl DTPA constructs of recombinant humanized anti-CD33 antibodies: pharmacokinetics, bioactivity, toxicity and chemistry.

UNLABELLED: The alpha-particle-emitting radionuclides have several physical characteristics that make them attractive candidates for radioimmunotherapy: (a) high linear energy transfer; (b) short path lengths (50-80 microm); and (c) limited ability of cells to repair damage to DNA. This article describes the pharmacokinetic, bioactivity, toxicity and chemical characteristics of alpha-particle-emitting, 213Bi and 212Bi radiometal conjugated HuM195 (anti-CD33) constructs. Conjugation of HuM195 to SCN-CHX-A-DTPA resulted in the attachment of up to 10 chelating ligand molecules per antibody. RESULTS: Radiolabeling efficiency of the CHX-A-DTPA-HuM195 construct with 213Bi was 78%+/-10% (n = 46) after 10 min at specific activities of up to 1110 MBq/mg. The immunoreactivity of the 213Bi-labeled CHX-A-DTPA-HuM195 construct was 84%+/-10% (n = 28) and was independent of the specific activity. The bismuth-labeled CHX-A-DTPA-HuM195 construct was rapidly internalized into the cell in a time-dependent manner ranging from 50% at 1 h to 65% at 24 h. 205Bi/206Bi-labeled constructs were stable for at least 2 d in vitro in the presence of human serum at 37 degrees C. After injection into mice, there was no uptake or loss of bismuth to mouse tissues, which do not express CD33, or to the kidney, which has avidity for free bismuth. Mice injected intraperitoneally with doses of (213Bi)CHX-A-DTPA-HuM1 95 ranging from 18.5 to 740 MBq/kg showed no toxicity, but at 2590 MBq/kg, two of the three mice died within 2 wk and a third mouse showed significant reductions in white blood cell counts. Mice injected intravenously with doses of (213Bi)CHX-A-DTPA-HuM195 up to 370 MBq/kg exhibited little toxicity, but 666 MBq/kg was above the MTD for mice. Leukemia cell killing in vitro with bismuth-labeled HuM1 95 showed dose- and specific activity-dependent killing of CD33+ HL60 cells; approximately 50% killing was observed when two bismuth atoms (50 fM radiolabeled antibody) were initially bound onto the target cell surface. CONCLUSION: Alpha-emitting antibodies are among the most potent cytotoxic agents known, yet are specific and appear safe in vivo. The physical and biochemical characteristics of the 213Bi isotope and its generation, as well as the biochemistry of the 213Bi-labeled CHX-A-DTPA-HuM195 construct, make it possible to use the constructs safely and feasibly in humans at therapeutic levels.

Alpha Particles↗

PubMed1998

[Study on the changes of the levels of SOD and MDA in lung and MN in bone marrow exposed to cooking fume in rats].

In order to investigate the mechanism of the activities of superoxide dismutase (SOD) and the concentration of malondialdehyde (MDA) in lung and rate of micro-nucleus (MN) in bone marrow by which rape oil fume condensate(RC) exert their effect in rat lung, pouring into traches SD rat was performed with RC. Results showed that the SOD activities in RC and B(a)P groups were significantly higher than those in DMSO and control groups(P < 0.05). The concentrations of MDA were significantly lower than that in DMSO and control groups (P < 0.05). In experimental groups SOD/MDA decreased. MN rate significantly increased. It is concluded that lung tissue may be a target of RC.

Air Pollutants↗

PubMed1998

Blockade of bepridil on IA and IK in acutely isolated hippocampal CA1 neurons.

The effects of bepridil, an antianginal agent with antiarrhythmic action, on voltage-dependent K+ currents in the CA1 pyramidal neurons acutely isolated from rat hippocampus were studied by means of whole-cell patch clamp techniques. Current recordings were made in the presence of TTX to block Na+ current. Depolarizing test pulses activated two components of outward K+ currents: a rapidly activating and inactivating component, IA; and a delayed component, IK. Results showed that bepridil reduced the amplitude of IA and IK, and exerted its inhibitory action in time- and dose-dependent manner. Half-blocking concentrations (IC50) of bepridil on IA and IK were 17.8 microM and 1.7 microM, respectively. 10 microM bepridil suppressed IA and IK by 46.7% and 77.1% at +30 mV of depolarization, respectively. When IK was activated nearly uncontaminated with IA by holding at -50 mV, 10 microM bepridil inhibited IK by 71.6% at +30 mV of depolarization; 10 microM bepridil positively shifted the voltage-dependent of activation curves of IA and IK 12.1 mV and 28.7 mV, respectively. These results suggested that blockade on K+ currents by bepridil is preferential for IK, and contributes to the protection brain against ischemic damage.

Animals↗

PubMed1998

Cell cycle- and Cln2p-Cdc28p-dependent phosphorylation of the yeast Ste20p protein kinase.

Ste20p from Saccharomyces cerevisiae is a member of the Ste20/p21-activated protein kinase family of protein kinases. The Ste20p kinase is post-translationally modified by phosphorylation in a cell cycle-dependent manner, as judged by the appearance of phosphatase-sensitive species with reduced mobility on SDS-polyacrylamide gel electrophoresis. This modification is maximal during S phase, and correlates with the accumulation of Ste20p fused to green fluorescent protein at the site of bud emergence. Overexpression of Cln2p, but not Clb2p or Clb5p, causes a quantitative shift of Ste20p to the reduced mobility form, and this shift is dependent on Cdc28p activity. The post-translational mobility shift can be generated in vitro by incubation of Ste20p with immunoprecipitated Cln2p kinase complexes, but not by immunoprecipitated Clb2p or Clb5p kinase complexes. Ste20p is therefore a substrate for the Cdc28p kinase, and undergoes a Cln2p-Cdc28p mediated mobility shift as cells initiate budding and DNA replication. In cells that express only the Cln2p G1 cyclin, minor overexpression of Ste20p causes aberrant morphology, suggesting a proper coordination of Ste20p and Cln-Cdc28p activity may be required for the control of cell shape.

CDC28 Protein Kinase, S cerevisiae↗

PubMed1998

Inorganic pyrophosphatase is a component of the Drosophila nucleosome remodeling factor complex.

The Drosophila nucleosome remodeling factor (NURF) is a protein complex consisting of four polypeptides that facilitates the perturbation of chromatin structure in vitro in an ATP-dependent manner. The 140-kD NURF subunit, imitation switch (ISWI), is related to the SWI2/SNF2 ATPase. Another subunit, NURF-55, is a 55-kD WD repeat protein homologous to the human retinoblastoma-associated protein RbAp48. Here, we report the cloning and characterization of the smallest (38 kD) component of NURF. NURF-38 is strikingly homologous to known inorganic pyrophosphatases. Both recombinant NURF-38 alone and the purified NURF complex are shown to have inorganic pyrophosphatase activity. Inhibition of the pyrophosphatase activity of NURF with sodium fluoride has no significant effect on chromatin remodeling, indicating that these two activities may be biochemically uncoupled. Our results suggest that NURF-38 may serve a structural or regulatory role in the complex. Alternatively, because accumulation of unhydrolyzed pyrophosphate during nucleotide incorporation inhibits polymerization, NURF may also have been adapted to deliver pyrophosphatase to chromatin to assist in replication or transcription by efficient removal of the inhibitory metabolite.

Amino Acid Sequence↗

PubMed1998

The X-linked lymphoproliferative-disease gene product SAP regulates signals induced through the co-receptor SLAM.

In addition to triggering the activation of B- or T-cell antigen receptors, the binding of a ligand to its receptor at the cell surface can sometimes determine the physiological outcome of interactions between antigen-presenting cells, T and B lymphocytes. The protein SLAM (also known as CDw150), which is present on the surface of B and T cells, forms such a receptor-ligand pair as it is a self-ligand. We now show that a T-cell-specific, SLAM-associated protein (SAP), which contains an SH2 domain and a short tall, acts as an inhibitor by blocking recruitment of the SH2-domain-containing signal-transduction molecule SHP-2 to a docking site in the SLAM cytoplasmic region. The gene encoding SAP maps to the same area of the X chromosome as the locus for X-linked lymphoproliferative disease (XLP) and we found mutations in the SAP gene in three XLP patients. Absence of the inhibitor SAP in XLP patients affects T/B-cell interactions induced by SLAM, leading to an inability to control B-cell proliferation caused by Epstein-Barr virus infections.

Amino Acid Sequence↗

PubMed1998

Interaction between caveolin-1 and the reductase domain of endothelial nitric-oxide synthase. Consequences for catalysis.

Endothelial nitric-oxide synthase (eNOS) is targeted to caveoli through interaction with caveolin-1 (cav-1). cav-1 binding to a consensus site in the eNOS oxygenase domain is proposed to antagonize calmodulin (CaM) binding and thereby inhibit eNOS nitric oxide (NO) synthesis. To study the mechanism, we examined how cav-1 scaffolding domain peptide (amino acids 82-101; cav-1P) would affect NO synthesis, NADPH oxidation, cytochrome c reduction, and ferricyanide reduction by full-length eNOS or its isolated oxygenase and reductase domains. Cav-1P equivalently inhibited NO synthesis and NADPH oxidation by full-length eNOS in a manner reversible by CaM but did not affect NADPH-independent NO synthesis by full-length eNOS or its oxygenase domain, indicating inhibition required the reductase domain. Similar concentrations of cav-1P inhibited cytochrome c reduction by full-length eNOS or the reductase domain (amino acids 492-1205) in a CaM-reversible manner, indicating cav-1P interaction with reductase or full-length eNOS are equivalent. Ferricyanide reduction was unaffected by cav-1P in all cases. Immunoblotting showed that full-length eNOS, eNOS oxygenase, and eNOS reductase all bound to an immobilized glutathione S-transferase-cav-1 fusion protein. Thus, cav-1 interacts independently with both oxygenase and reductase domains of eNOS. The reductase interaction occurs independent of a cav-1 binding motif, is CaM-reversible, and is of sufficient affinity to match cav-1P inhibition of NO synthesis by full-length eNOS. We propose that cav-1 binding to eNOS reductase compromises its ability to bind CaM and to donate electrons to the eNOS heme, thereby inhibiting NO synthesis.

Amino Acid Sequence↗

PubMed1998

Physical parameters and biological stability of yttrium(III) diethylenetriaminepentaacetic acid derivative conjugates.

The solution equilibria, acid dissociation, and serum stability of a series of Y(III) complexes of DTPA ligands functionalized with p-nitrobenzyl, methyl, and trans-cyclohexyl substituents were studied. The thermodynamic stability of the complexes studied ranged from log K = 21.53 to 24.7. Acid dissociation rates were found to decrease as the substitution on the carbon backbone increased, and significant differences in dissociation rates were observed for the Y(III) complexes of a pair of diasteriomeric cyclohexyl-DTPA ligands. While one diastereomer was found to have the slowest acid dissociation rate of the entire DTPA series, it was remarkably labile in both serum stability and in vivo studies.

Animals↗

PubMed1998

Mcm1 regulates donor preference controlled by the recombination enhancer in Saccharomyces mating-type switching.

Switching of Saccharomyces mating type by replacement of sequences at the MAT locus involves a choice between two donors, HML and HMR. MATalpha cells inhibit recombination along the entire left arm of chromosome III, including HML, whereas MATa cells activate this same region. MATa-dependent activation of HML depends on a small, cis-acting DNA sequence designated the recombination enhancer (RE), located 17 kb centromere-proximal to HML. A comparison of RE sequences interchangeable between Saccharomyces cerevisiae and Saccharomyces carlsbergensis defines a minimum RE of 244 bp. RE activity is repressed in MATalpha cells by binding of the Matalpha2-Mcm1 corepressor to a site within the RE. Mutation of the two Matalpha2 binding sites removes most, but not all, of this repression, and RE chromatin structure in MATalpha cells becomes indistinguishable from that seen in MATa. Surprisingly, a 2-bp mutation in the Mcm1 binding site completely abolishes RE activity in MATa cells; moreover, RE chromatin structure in the MATa mutant becomes very similar to that seen in MATalpha cells with a normal RE, displaying highly ordered nucleosomes despite the absence of Matalpha2. Further, a mutation that alters the ability of Mcm1 to act with Matalpha2 in repressing a-specific genes also alters donor preference in either mating type. Thus, Mcm1 is critically responsible for the activation as well as the Matalpha2-Mcm1-mediated repression of RE activity.

Base Sequence↗