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L Yu

Publications and source records attributed to L Yu.

At least 91 records · Page 5Linked to original sources
PubMed2001

Location of the epitope for 7D5, a monoclonal antibody raised against human flavocytochrome b558, to the extracellular peptide portion of primate gp91phox.

Flavocytochrome b558 is the membrane component of the phagocyte NADPH oxidase, and is a heterodimer composed of gp91phox and p22phox subunits. Human flavocytochrome b558 is recognized by monoclonal antibody 7D5 at an unidentified extracellular domain, although our previous study suggested it might recognize p22phox. 7D5 has proven useful in rapid screening of individuals for X-linked chronic granulomatous disease by flow-cytometry. Therefore, we re-evaluated the location of the 7D5 epitope using gene-engineered cell lines expressing hybrid flavocytochromes composed of human and murine subunit homologues. The current study demonstrates that the 7D5 recognizes epitope only of primate gp91phox. Flow-cytometric analyses showed that 7D5 consistently bound to cells expressing human gp91phox. In addition, 7D5 immunoprecipitated the approximately 58 kDa unglycosylated gp91phox protein from solubilized membrane fractions of tunicamycin-treated PLB-985 granulocytes, indicating that glycans were not required for 7D5 binding. Transgenic COS7 cells expressing human gp91phox but not p22phox were recognized by 7D5. These results localized the epitope of 7D5 to an extracellular peptide portion of primate gp91phox and indicate that the antibody will be useful for monitoring the efficiency of gene therapy in patients with flavocytochrome b558-deficient chronic granulomatous disease and for elucidating structural characteristics of flavocytochrome b558.

3T3 Cells↗
PubMed2001

Characterization of newly emerging Newcastle disease virus isolates from the People's Republic of China and Taiwan.

Seven Newcastle disease (ND) virus (NDV) isolates which were recovered from ND outbreaks in chicken and pigeon flocks in China and Taiwan between 1996 and 2000 were genotypically and pathotypically characterized. By phylogenetic analysis of the fusion protein genes, isolates Ch-A7/96, Ch/98-3, Ch/99, Ch/2000, and TW/2000 were placed into two novel subgenotypes, VIIc and VIId. Isolate Ch/98-1 was grouped into subgenotype VIb, while Ch-W6/96 was proven to be a mixture of isolates Ch-A7/96 and Ch/98-1. These isolates were pathotyped as viscerotropic velogenic for Ch/98-3, Ch/99, Ch/2000, and TW/2000; neurotropic velogenic for Ch-A7/96; and mesogenic for Ch/98-1. Three separate, comparative, genetic analyses of the F genes, including genetic distance measurement, phylogenetic tree analysis, and residue substitution analysis, were performed with our isolates and selected NDV strains from GenBank. Results showed that the close genetic similarity provided evidence for the epidemiological linkage between the outbreaks in China and Taiwan and that the 1990s outbreaks in Asia, the Middle East, Africa, and Europe constituted the fourth panzootic of ND. In combination with epidemiological analysis, an evolutionary model of the NDV strains, representative of the direction of transmission within the NDV strains, was proposed, and epidemiology of NDV transmission was evaluated with emphasis on molecular aspects. Finally, a cross-protective experiment indicated that at least one strain (Ch-A7/96) among our NDV isolates was an antigenic variant, responsible for recent outbreaks of ND in vaccinated chicken flocks.

Animals↗
PubMed2001

Biostability and pharmacokinetics of LJP 920, an octameric Gal (alpha1-3) Gal conjugate for the inhibition of xenotransplantation rejection.

Antibodies to an alpha-galactosyl saccharide structure present in human serum are associated with hyperacute rejection and delayed xenograft rejection after pig-to-primate xenotransplantation. To overcome this major barrier to the xenotransplantation, LJP 920, a galactosyl alpha1-3 galactose (Gal (alpha1-3) Gal) coupled to a non-immunogenic platform at a valency of eight Gal (alpha1-3) Gal molecules/platform, was synthesized to clear circulating antibodies and to inhibit their production by B cells that produce these antibodies. Herein we report on the stability of UP 920 in biological media and its pharmacokinetic profile. Incubation of LJP 920 with mouse serum or liver microsomes at 37 degrees C for 2 days showed no indication of degradation of the conjugate as detected by a reversed-phase HPLC method, indicating that the conjugate is not subject to enzymatic metabolism. After intravenous administration of LJP 920 to mice at the doses of 20 and 100 mg kg(-1), UP 920 serum concentration decreased rapidly, showing a biphasic pattern, with a distribution half-life of 3 min and an elimination half-life of more than 30 min, respectively. The serum-to-erythrocyte concentration ratio of UP 920 was 33- and 36-fold excess at 0.5 and 5 min, respectively, after intravenous administration (100 mg kg(-1)). Both Cmax and AUC values increased in a dose-proportional manner. UP 920 displayed a great distribution to well-perfused tissues. It was eliminated mainly through renal excretion in the unchanged form, which accounted for 23% of the total amount within 8 h of dosing.

Animals↗
PubMed2001

Hepatosplenic gamma/delta T-cell lymphoma in immunocompromised patients. Report of two cases and review of literature.

We describe 2 male patients in whom hepatosplenic gamma/delta T-cell lymphoma (HSTL) developed 6 and 10 years after renal transplantation. The onset was abrupt with systemic symptoms, cytopenia, and hepatosplenomegaly. The histologic examination of the spleen (case 1), liver, and bone marrow revealed sinusoidal infiltrates of markedly abnormal lymphocytes. The neoplastic cells in these cases were CD2+, CD3+, CD4-, CD5-, CD7+, CD8+, CD16+, CD56+, beta F1-negative, and TIA-1-negative. Both cases displayed clonal rearrangement of the T-cell receptor (TCR) delta gene and the TCR beta gene. The spleen in case 1 was positive for Epstein-Barr virus genome and showed TCR-gamma gene rearrangement by polymerase chain reaction. Isochromosome 7 [i(7)(q10)] was found in each case. Both patients died within 4 months of diagnosis. HSTL has been reported in only 5 renal transplant recipients. HSTL may be relatively more frequent in immunocompromised patients compared with the general population.

Adult↗
PubMed2001

Iterative algorithm with a constraint condition for numerical reconstruction of a three-dimensional object from its hologram.

A novel method to obtain the three-dimensional mathematical model of a transparent object from its hologram is presented. The proposed method can numerically extract the object information from the fringe pattern of the hologram. Then an iterative algorithm is used to imitate an imaging system by focusing on different layers of the object; and by operating in both the spatial domain and the frequency domain, the algorithm produces a series of two-dimensional layer images. The object is finally reconstructed layer by layer. A constraint condition should be satisfied, and the noise distribution can be rearranged in different reconstruction cycles so as to get better reconstruction quality. Numerical simulations have proved the effectiveness of the proposed method.

Journal Article↗
PubMed2001

Peptide and major histocompatibility complex-specific breaking of humoral tolerance to native insulin with the B9-23 peptide in diabetes-prone and normal mice.

NOD mice spontaneously develop anti-insulin autoantibodies and diabetes. A dominant peptide recognized by T-cell clones from NOD mice is insulin B-chain peptide B9-23. When administered subcutaneously to NOD mice, this peptide decreases the development of diabetes. In this study, we evaluated the autoantibody response to native insulin after administration of the B9-23 peptide. In NOD mice, administration of the B9-23 peptide in incomplete Freund's adjuvant enhanced their insulin autoantibody response with a higher level and longer persistence. Induction of insulin autoantibodies with the B9-23 peptide was observed in non-diabetes-prone BALB/c mice and NOR mice within 2 weeks of administration, but this was not observed in C57BL/6 mice. A series of A-chain, other B-chain, and proinsulin peptides did not induce insulin autoantibodies. Induced anti-insulin autoantibodies could not be absorbed with the peptide alone but could be absorbed with native insulin. The B13-23 peptide (one of two identified epitopes within B9-23) when administered to BALB/c mice, induced autoantibodies, whereas peptide B9-16 did not. Induction of autoantibodies mapped to the major histocompatibility complex (MHC) rather than to the background genes. Both splenocytes with I-A(d)/I-E(d) or I-A(g7)/I-E(null) presented the B9-23 peptide to NOD islet-derived T-cell clones. Finally, administration of the B9-23 peptide to BALB/c mice, even without adjuvant, could induce insulin autoantibodies. Our results indicate that B-cell tolerance to intact insulin is readily broken with the presentation of the B9-23 insulin peptide, depending on the host's specific MHC.

Animals↗
PubMed2001

Expression of GAD65 and islet cell antibody (ICA512) autoantibodies among cytoplasmic ICA+ relatives is associated with eligibility for the Diabetes Prevention Trial-Type 1.

More than 71,000 relatives of type 1 diabetic patients have been screened for cytoplasmic islet cell antibodies (ICAs), GAD65 autoantibodies (GAAs), and ICA512 autoantibodies (ICA512AAs). Among those 71,148 relatives, 2,448 were cytoplasmic ICA+, and the remainder were ICA-. Of the ICA+ group, 1,229 (50.2%) were positive for GAAs and/or ICA512AAs. Among ICA- relatives, 1,897 (2.76%) were positive for GAAs and/or ICA512AAs. Given the large number of relatives positive for cytoplasmic ICA and negative for "biochemically" determined autoantibodies, and the converse, we analyzed the proportion of ICA+ relatives found eligible to participate in the intervention phase of Diabetes Prevention Trial-Type 1 (DPT-1). To be eligible for the parenteral insulin DPT-1 trial, a relative had to have first-phase insulin secretion below the 1st percentile of cut-points (for parents) or below the 10th percentile (for siblings and offspring). To be eligible for the oral insulin trial, a relative had to have first-phase insulin secretion above cut-points (>1st percentile for parents, >10th percentile for siblings/offspring) and be positive for anti-insulin autoantibodies. For both trials, DQB1*0602 was an exclusion criteria, cytoplasmic ICA positivity had to be confirmed, and an oral glucose tolerance test had to result in nondiabetic levels. Of 572 relatives found to be eligible for trial entry, 442 (77.3%) were positive for GAAs and/or ICA512AAs, although overall only 50.2% of ICA+ relatives were positive for GAAs and/or ICA512AAs. The positive predictive value for trial eligibility for ICA+ relatives with GAAs or ICA512AAs who completed staging was 51.0%. In contrast, only 11.9% of ICA+ but GAA- and ICA512AA- relatives were found to be eligible by DPT criteria for trial entry. Positivity for biochemically determined autoantibodies among cytoplasmic antibody-positive relatives is associated with eligibility for the DPT-1 study.

Adolescent↗
PubMed2001

[Cloning and characterization of pathogenesis-related protein 1 from wheat-H. villosa translocation lines].

A Triticum aestivum-Haynaldia villosa 6VS/6AL translocation line contained powdery mildew resistance gene Pm21 which is effective against all the current biotypes of Erygsiphe gramins. Cloning of the related genes for powdery mildew resistance is significance for understanding its resistance mechanism and disease resistance breeding. Using RT-PCR and RACE technology, a wheat pathogenesis related protein 1 cDNA clone (TaPr-1) corresponding to a mRNA differentially induced in resistant 6VS/6AL translocation line compared to susceptible wheat cultivar "Yangmai 5" by powdery mildew infection was isolated and characterized. This sequence contained 823 bp and had an open reading frame (ORF) containing 164 amino acids with 24 amino acids in the putative signal peptide and 140 amino acids comprising the mature peptide (15.1 kD). The deduced amino acid sequence showed close homology to PR-1 like proteins, which have been isolated from many plants. Northern blot analysis revealed the most abundantly accumulation of the corresponding mRNA 12 h after infection in translocation line (6VS/6AL). The obviously difference in the expression of the PRw-1 was also observed between resistant translocation line (6VS/6AL) and susceptible parent "Yangmai 5", it showed the TaPr-1 gene is related to powdery mildew resistance. Southern blot indicated that the wheat genome contains more than one copies of TaPr-1 genes, and there are polymorphism between translocation lines and "Yanmai 5", the result shows that 6VS may contain TaPr-1 genes.

Amino Acid Sequence↗
PubMed2001

Extracellular protons inhibit the activity of inward-rectifying potassium channels in the motor cells of Samanea saman pulvini.

The intermittent influx of K+ into motor cells in motor organs (pulvini) is essential to the rhythmic movement of leaves and leaflets in various plants, but in contrast to the K+ influx channels in guard cells, those in pulvinar motor cells have not yet been characterized. We analyzed these channels in the plasma membrane of pulvinar cell protoplasts of the nyctinastic legume Samanea saman using the patch-clamp technique. Inward, hyperpolarization-activated currents were separated into two types: time dependent and instantaneous. These were attributed, respectively, to K+ -selective and distinctly voltage-dependent K(H) channels and to cation-selective voltage-independent leak channels. The pulvinar K(H) channels were inhibited by external acidification (pH 7.8-5), in contrast to their acidification-promoted counterparts in guard cells. The inhibitory pH effect was resolved into a reversible decline of the maximum conductance and an irreversible shift of the voltage dependence of K(H) channel gating. The leak appeared acidification insensitive. External Cs (10 mM in 200 mM external K+) blocked both current types almost completely, but external tetraethylammonium (10 mM in 200 mM external K+) did not. Although these results do not link these two channel types unequivocally, both likely serve as K+ influx pathways into swelling pulvinar motor cells. Our results emphasize the importance of studying multiple model systems.

Biological Transport↗
PubMed2001

[Correction of nasal deformity in unilateral cleft lip of adult cases].

OBJECTIVE: Nasal deformities are very common in unilateral cleft lip cases. They are morphology of alar collapse, nasal floor depression and deviation of the septum. METHODS: Our operation procedure includes correction and replacement of the septum to the middle position, mobilization and suspension of the displaced alar cartilage and use of a "C" flap, nasal sill flap or a flap of the lip scar tissue to increase the length of columella on the cleft side. An implant or autograft of suitable size is placed, if necessary, in the nasal bridge or/and the nasal floor. RESULTS: Postoperative follow-up for 1-12 months showed that the results are satisfactory. CONCLUSIONS: Correction of septum deformity, and increase of the length of the columella on the cleft side are important. An extensive mobilization and reposition of the alar cartilage must be done for obtaining a symmetric nasal projection. If necessary, a fine implant or self-tissue is placed in the nasal bridge and nasal floor, which would make the result much better.

Adult↗
PubMed2001

[Genetic polymorphism of polyacrylamide gel electrophoresis loci in patients after non-myeloablative allogeneic peripheral blood stem cell transplantation].

OBJECTIVE: To understand the information of donor and recipient in the mixed hematopoietic chimerism after non-myeloablative allogeneic peripheral blood stem cell transplantation(NM-APBSCT). METHODS: DNA samples were extracted with phenol/chloroform method and were amplified by PCR technique in heparin-blood or heparin-bone-marrow. The PCR products were analyzed using polyacrylamide gel electrophoresis and silver staining means. RESULTS: The amplified fragment length polymorphism was found in the short tandem repeat loci of 10 healthy persons and 8 leukemia patients who were not treated with hematopoietic stem cells transplantation; the bands of silver staining originated from donors and recipients were found in 3 patients after NM-APBSCT, but the brightness in the bands of donor and recipient was different. CONCLUSION: Polymorphism for mixed hematopoietic chimerism can be estimated timely, sensitively and exactly; and the results may be used to guide adoptive immunotherapy for patients after NM-APBSCT. The silver means were simple without contamination of isotopes and without using special equipment. The methods may benefit common hospitals to develop work in this respect.

DNA, Neoplasm↗
PubMed2001

[Microsatellite instability in renal cell carcinoma and its mechanisms].

OBJECTIVE: To study the expression of microsatellite instability (MSI) in renal cell carcinoma (RCC) and its relationship with gene mutation. METHODS: Tumor samples from 34 patients with RCC were analyzed for MSI by PCR. RT-PCR was used to evaluate the expression of mRNA of 5 human mismatch repair (MMR) genes in RCC and RCC cell lines. Mutation of hMLH1 gene coding regions was detected by PCR-SSCP. PCR was used to check the mutations of TGF-beta R II gene and BAX gene in 15 MSI-positive samples of RCC. RESULTS: Microsatellite changes were detected in 15 of 34 patients with RCC (44.1%). It might be associated with the progression of this disease. There were 3 of 15 MSI-positive RCC cases without expression of MMR gene hMLH1, and in 3 of 15 cases its expression was decreased. All 5 MMR genes were expressed in normal and RCC 949 cell line. There were three mutations in 15 MSI-positive cases. Frame shift mutation of TGF beta R II gene and BAX gene was found in 6 and 4 of the 15 cases with MSI, respectively, but it was not found in MSI-negative RCC and normal tissue. CONCLUSION: MSI and expression of MMR genes are associated events in RCC. The effect of gene mutation on tumorgenerasis may be related to MSI.

Adaptor Proteins, Signal Transducing↗
PubMed2001

[beta-elemene induces apoptosis of K562 leukemia cells].

OBJECTIVE: To investigate the apoptosis-inducing effect of beta-elemene on K562 leukemia cells. METHODS: Hoechst 33342 and PI fluorescence staining, DNA fragmentation, electron microscopy, flow cytometry, and immunocytochemistry were used to evaluate the effect of beta-elemene on K562 cells. RESULTS: beta-elemene heatment induced the formation of apoptotic bodies and DNA ladder. The effect was dose- and time-dependent. The expression of bcl-2 was decreased in beta-elemene treated cells as compared with the untreated control cells. CONCLUSION: beta-elemene exerts its cytotoxic effect on K562 leukemic cells by the induction of apoptosis.

Apoptosis↗
PubMed2001

[Internal strontium-89 radiotherapy for malignant bony metastasis].

OBJECTIVE: This work was done to evaluate the indication, effectiveness, and side effects of internal radiotherapy with radioactive nuclide strontium-89 (89Sr) in patients with malignant metastasis in the bone. METHODS: Fifty-six patients with skeletal metastasis received this internal radiotherapy. The patients were observed and followed up with respect to pain control, lesion improvement and side effects. RESULTS: The overall effective rate of pain control was 76.8% with the effective rate of prostatic cancer and breast cancer higher than 80%. The lesions in 81.8% patients as assessed by SPECT imaging, were improved. The mild lowering of white cells, platelets and red cells was the main side effect. CONCLUSION: Internal radiotherapy with 89Sr is very useful for patients with malignant cancer metastasis in the bone.

Adult↗
PubMed2001

[p15 gene expression in acute lymphoblastic leukemia cell line Molt4 induced by arsenic trioxide].

OBJECTIVE: To explore the correlation between arsenic trioxide and gene methylation in an acute lymphoblastic cell line. METHODS: Methylation of p15 gene in Molt4 cell line was detected by polymerase chain reaction (PCR) using methylation specific primer (MSP) and the expression of this gene after arsenic trioxide treatment was detected by reverse transcriptase PCR (RT-PCR). The cell cycle and cell growth curve were also observed by flow cytometry. RESULTS: p15 gene failed to express in molt4 after methylation. The expression was recovered, cell growth was inhibited, and G(1) cell cycle arrest was observed, when the cells exposed to arsenic. CONCLUSION: Arsenic trioxide could activate the expression of p15 gene and reverse cell cycle negative regulation.

Acute Disease↗
PubMed2001

A chronic inflammatory infusion model of peritoneal dialysis in rats.

OBJECTIVES: Peritoneal membrane changes are related to daily exposure to non physiologic dialysate and recurrent acute inflammation. We modified a daily infusion and inflammation model and evaluated it for fibrotic and angiogenic features. The feasibility of adenovirus-mediated gene transfer in the model was also assessed. METHODS: Peritoneal catheters were implanted in rats. Over a period of 4 weeks, the animals received a daily infusion of Dianeal 4.25% (Baxter Healthcare Corporation, Deerfield, IL, U.S.A.) with an initial three doses of lipopolysaccharide (LPS) or physiologic saline. Peritoneal fluid was assayed for transforming growth factor beta (TGFbeta) and vascular endothelial growth factor (VEGF). Animals were humanely killed at week 5. Net ultrafiltration was then measured, and tissue samples were immunostained for factor VIII. Mesenteric tissue was assayed for hydroxyproline content. Adenovirus-mediated gene transfer of beta-galactosidase was assayed by intraperitoneal administration of the virus, 4 days before the end of the experiment. RESULTS: Animals treated with either Dianeal or physiologic saline showed peritoneal membrane thickening and increased vascularity. Fibrosis was demonstrated by increased hydroxyproline concentration. Ultrafiltration was impaired. We found increased concentrations of VEGF and TGFbeta in the peritoneal fluid of animals treated with LPS and daily infusion. Adenovirus-mediated gene transfer to the peritoneal membrane was demonstrated in the model. CONCLUSIONS: Exposure to LPS and daily Dianeal or physiologic saline leads to peritoneal fibrosis and neoangiogenesis. Vascularization and glucose transport correlate with ultrafiltration failure. The present animal model mimics changes seen in humans on peritoneal dialysis and may be valuable for evaluating short-term interventions to prevent membrane damage.

Adenoviridae↗
PubMed2001

[Enhanced immunogenicity of plasmid encoding polyprotein gene of infectious bursal disease virus by co-administration of chicken interleukin 2 (IL-2)].

Chicken interleukin 2 (IL-2) is one of important nonmammalian cytokines isolated recently. The influencing of IL-2 on immunogenicity of DNA vaccine was examined using infectious bursal disease virus as a model. The IL-2 cDNA of Xiaoshan chicken and the polyprotein gene of IBDV-ZJ2000 were amplified by RT-PCR, cloned, sequenced and inserted into the control of CMV promoter and enhancer of pCI vector. 14-day-old chickens were vaccinated intramuscularly with DNA vaccine, two weeks later, they were boosted with DNA, and two weeks post boost, they were challenged with virulent IBDV. The results showed that protective responses and neutralization antibody responses of DNA vaccine co-administrated with chicken IL-2 were much higher than those of injected with DNA vaccine alone. Furthermore, the T lymphocyte proliferation response of peripheral blood, thymus and spleen, and the B lymphocyte proliferation response of bursa induced by DNA vaccine can be significantly enhanced by chicken IL-2. These results obviously indicated that chicken IL-2 was a strong adjuvant which can significantly enhance the immunogenicity of IBDV DNA vaccine.

Animals↗