Biomedical subjects

Hong Yu

Publications and source records attributed to Hong Yu.

At least 109 records · Page 6Linked to original sources

PubMed2004

[Therapeutical effects of esculentoside A on rats with MsPGN induced by anti-Thy1.1 antibody].

OBJECTIVE: To observe the therapeutical effects of esculentoside A (EsA) on rats with mesangial proliferative glomerulonephritis (MsPGN) induced by anti-Thy1.1 antibody and make a comparison of the effects between EsA and dexamethasone (DXM). METHODS: Wistar rats with MsPGN induced by anti-Thy1.1 serum (ATS) were randomly divided into 3 groups: EsA group, DXM group, and model group. Moreover, a normal group was used for comparison. The BUN, SCr, urinary protein and renal pathological changes were examined after 7 d treatment with EsA and DXM. RESULTS: The urinary protein, cell count and mesangium area of glomerulus were significantly higher in all modeled groups than in normal group (P<0.001-0.05), and they were significantly lower in the treated groups than in untreated group (P<0.001-0.01). CONCLUSION: The results suggest that EsA is effective for reducing the urinary protein excretion and inhibiting the proliferation process of glomerular mesangium and matrix in rats with MsPGN.

Animals↗

PubMed2004

[Construction, expression and bioactivity characterization of targeting toxin DT-VEGF].

Tumor rapid growth depends on neovascularization. Vascular endothelial growth factor, the main mediator during the occurrence and formation of vascularization, has specific receptors whose expression rate shows difference of orders of magnitude between tumor and the normal tissue, so it can be used to transport toxin molecules to the proliferative tumor endothelial and kill cancer cells. In our experiment, we constructed fusion protein DT-VEGF by linking diphtheria toxin's forward 389 amino acids's gene and VEGF165 via a linker. DT-VEGF is expressed in E. coli and purified. Our experiment proves in can kill vascular endothelial cells specifically, and the inhibition of neovascularization of chicken chorionic membrane is also confirmed.

Angiogenesis Inhibitors↗

PubMed2004

[Effect of the expression of glycosylphosphatidylinositol-specific phospholipase D gene on K562 cell sensitivity to complement killing].

OBJECTIVE: To detect the release of glycosylphosphatidylinositol (GPI) anchored CD55 and CD59, and the effect of complement dependent cytotoxicity on K562 cell with expression of GPI-PLD by glucose or insulin. METHODS: CD55 and CD59 were detected by Western blotting; GPI-PLD activities were analyzed quantitatively; and complement dependent cytotoxicity (CDC) effects were observed by staining of trypan blue. RESULTS: After being induced by insulin or glucose for 24 h and 48 h, GPI-PLD activities and rate of CDC killing in the insulin, insulin + glucose groups significantly increased. At 24 h after the inducement, CD55 was found in the membrane proteins in the control, glucose and insulin groups and CD59 in membrane proteins in the control, glucose group, and medium supernatants of insulin, glucose + insulin groups. Both CD55 and CD59 were found in membrane proteins in control group, and medium supernatants of glucose, insulin, glucose + insulin group at 48 h after the inducement. CONCLUSION: Treatment with insulin resulted in the obvious increase of GPI-PLD activity in K562 cell, which led to releasing of GPI anchored CD55 and CD59 into medium, and increased sensitivity of these cells to CDC killing.

CD55 Antigens↗

PubMed2003

Multiple apoptotic caspase cascades are required in nonapoptotic roles for Drosophila spermatid individualization.

Spermatozoa are generated and mature within a germline syncytium. Differentiation of haploid syncytial spermatids into single motile sperm requires the encapsulation of each spermatid by an independent plasma membrane and the elimination of most sperm cytoplasm, a process known as individualization. Apoptosis is mediated by caspase family proteases. Many apoptotic cell deaths in Drosophila utilize the REAPER/HID/GRIM family proapoptotic proteins. These proteins promote cell death, at least in part, by disrupting interactions between the caspase inhibitor DIAP1 and the apical caspase DRONC, which is continually activated in many viable cells through interactions with ARK, the Drosophila homolog of the mammalian death-activating adaptor APAF-1. This leads to unrestrained activity of DRONC and other DIAP1-inhibitable caspases activated by DRONC. Here we demonstrate that ARK- and HID-dependent activation of DRONC occurs at sites of spermatid individualization and that all three proteins are required for this process. dFADD, the Drosophila homolog of mammalian FADD, an adaptor that mediates recruitment of apical caspases to ligand-bound death receptors, and its target caspase DREDD are also required. A third apoptotic caspase, DRICE, is activated throughout the length of individualizing spermatids in a process that requires the product of the driceless locus, which also participates in individualization. Our results demonstrate that multiple caspases and caspase regulators, likely acting at distinct points in time and space, are required for spermatid individualization, a nonapoptotic process.

Animals↗

PubMed2003

Effects of long-term administration of the 5-hydroxytryptamine1B receptor antagonist AR-A000002 to guinea pigs.

RATIONALE: Recently a new 5-hydroxytryptamine1B (5-HT1B)-receptor antagonist, AR-A000002, was described. It was shown that this compound dose dependently increased 5-HT metabolism and release in guinea pig brain following a single injection. OBJECTIVES: The present study investigated effects of 3 weeks twice-daily treatment of guinea pigs with the 5-HT1B-receptor antagonist AR-A000002 on the serotonergic neurons and receptor densities. METHODS: Guinea pigs were injected subcutaneously with AR-A000002, citalopram or saline twice daily for 3 weeks. Groups of animals were treated with challenge doses of AR-A000002 or saline 24 h after the last chronic treatment (citalopram group 48 h) and sacrificed 2 h thereafter. The effect on 5-HT metabolism and 5-HT release was assessed. Plasma and brain concentrations of AR-A000002 were analysed. The effects on binding of [3H]8-OH-DPAT to 5-HT1A receptors, [3H]GR125743 to 5-HT(1B/1D) receptors, [3H]ketanserin to 5-HT2A receptors, and [3H]prazosin to alpha1-adrenoceptors were determined. RESULTS: Repeated treatment of guinea pigs with AR-A000002 did not change the 5-HT(1B/1D), 5-HT1A, 5-HT2A or alpha1-adrenergic receptor densities. Following repeated treatment of guinea pigs for 3 weeks with AR-A000002, the 5-HT1B receptors were still receptive to a challenge with the same compound. Thus, an increase in the 5-HIAA/5-HT ratio and 5-HT release was seen following challenge doses of AR-A000002. No difference in the plasma and brain concentrations of AR-A000002 was found between the sub-chronic treated AR-A000002 and saline-treated guinea pigs. CONCLUSIONS: It is concluded that AR-A000002 is a 5-HT1B receptor antagonist, which enhances persistently the serotonergic neurotransmission in guinea pig brain.

Animals↗

PubMed2003

Exploring the site of anorectic action of peripherally administered synthetic melanocortin peptide MT-II in rats.

Melanotan-II (MT-II), a cyclic heptapeptide, is a potent, non-selective melanocortinergic agonist. When administered centrally or systemically, MT-II elicited a profound inhibitory effect on food intake in rodents, presumably via activation of melanocortin-4-receptor (MC4R). In this study, we sought to investigate whether penetration of MT-II and iodo-MT-II into brain parenchyma is required for the anorectic effect following intravenous (IV) administration. Firstly, both MT-II and iodo-MT-II were effective at suppressing appetite in rats following their IV administration. We next surveyed by in vitro autoradiographic studies the distribution of selective (125)I-MT-II binding sites in multiple brain regions including areas important for feeding regulation such as the hypothalamus and caudal brainstem. Upon IV administration of (125)I-MT-II, significant radioactivity could not be detected in various brain regions by autoradiography except for a group of circumventricular organs (CVOs), which are anatomically situated outside the blood-brain barrier (BBB). The most intensely labeled CVOs include the subfornical organ, median eminence, area postrema and choroid plexus, and accumulation of radioactivity at these sites can be blocked by co-injection of excess unlabeled MT-II. Direct measurement of MT-II in the brain and plasma by LC-MS-MS following IV injection confirmed that the degree of MT-II penetration into the brain is negligible. Furthermore, when given peripherally under conditions that suppressed food intake, MT-II did not result in a detectable induction of c-Fos-like immunoreactivity in brain regions where a significantly elevated c-Fos expression was observed following intracerebroventricular injection of this peptide. Our results indicate that MT-II has a very limited brain penetration capability, and its effect on feeding behavior following systemic administration may be mediated by either the brain regions in close proximity to the CVOs or sites outside of the BBB, including CVOs or other peripheral systems.

Animals↗

PubMed2003

[Clinical analysis of 45 patients with severe acute respiratory syndrome].

OBJECTIVE: To explore the clinical and radiology features of Severe Acute Respiratory Syndrome (SARS). METHODS: Analysis the clinical presentations, chest radiographs, courses of disease and the features of severe pneumonia of 45 cases with SARS diagnosed between April 5 and April 20, 2003 in our hospital. RESULTS: SARS appears to has high infectivity, and cause of the outbreak. The most common symptom is fever (in 100 percent of the patients). The count of leukocyte is normal or decrease (leukopenia). 80 percent of SARS patients became fever for 24 hours and then have abnormal chest radiographs, serial chest radiographs showed progression of pulmonary infiltrates within 48 hours in 71.1 percent of patients. The percent of severe pneumonia (24.4%) is higher than typical pneumonia. CONCLUSION: SARS is a disease with high infectivity, and has its own clinical and radiology features. Early recognition, prompt isolation, and appropriate therapy are the key in combating this infection.

Adult↗

PubMed2003

Some factors affecting separation and detection of amino acids by high-performance anion-exchange chromatography with integrated pulsed amperometric detection.

Some factors influencing the separation and detection of amino acids by high-performance anion-exchange chromatography with integrated pulsed amperometric detection were investigated. These factors include eluent concentration, column temperature, and detection waveform. The selectivity changes in weakly retained amino acids are slight with changing sodium hydroxide eluent concentration. When sodium acetate eluent concentration is changed, the selectivity variations between strongly retained amino acids containing two carboxyl groups and containing only one carboxyl group are obviously different. Significant but slight selectivity changes in weakly retained amino acids can be achieved through changing the column temperature. Sodium hydroxide and sodium acetate eluent concentration affect the detection of amino acids. Detection sensitivity of amino acids can be improved by increasing the concentration of sodium hydroxide and sodium acetate in a certain concentration range. The detections of amino acids at two different detection waveforms were compared. The hydroxyl amino acids can be selectively detected by choosing a modified detection waveform. The optimized gradient elution condition and column temperature for analyzing 19 amino acids were obtained. The time for the gradient elution program was 60 min. The column temperature was 35 degrees C. Under the optimized conditions, detection limits for 19 amino acids were 0.15-4.52 pmol. The calibration graphs of peak area for all the analytes were linear for about three orders of magnitude. The RSDs (n=5) of peak area were 0.6-5.6%. The determination of trace amino acid impurities in valine product is shown as an application example.

Amino Acids↗

PubMed2003

Off-line elimination of carbohydrates for amino acid analysis of samples with high carbohydrate content by ion-exchange chromatography.

This paper introduces a new off-line sample preparation that eliminates carbohydrates from amino acid samples containing a high carbohydrate content before analysis by anion-exchange chromatography and integrated pulsed amperometric detection. First, the sample is introduced into a cation-exchange column in the hydrogen form. Carbohydrates are removed completely using 0.02% formic acid as a transfer fluid, while only amino acids are retained. Amino acids are then extracted from the cation-exchange resin by 10 ml of 1 M ammonia. The ammonia collected is evaporated to dryness and the residue redissolved in water containing 20 mg/l NaN3 for injection. All amino acids are recovered following the carbohydrate removal step. The average recovery is 97.2%. The relative standard deviation for seven replicates is less than 5.2%. The usefulness of the method is illustrated with chromatograms of ratafia samples obtained before and after the off-line removal of carbohydrates.

Amino Acids↗

PubMed2003

Migration of mesenchymal stem cells to heart allografts during chronic rejection.

BACKGROUND: Mesenchymal stem cells (MSC) are pluripotent progenitors for a variety of cell types, including fibroblasts and muscle cells. Their involvement in the tissue repair of allografts during the development of chronic rejection has been hypothesized, but not yet substantiated, by experimental evidence. METHODS: Rat MSC were isolated from circulation using an aortic pouch allograft as a trapping device. The plasticity of these cells was examined in differentiation cultures. One of the resulting MSC lines was immortalized and transduced to express a marker gene. The -labeled cells were then transferred to F344 rats bearing Lewis (LEW) cardiac allografts to measure their localization and contribution to graft tissue repair. RESULTS: The MSC isolated from circulation exhibited multipotential for differentiation in culture, developing into various lineages including osteoblasts, lipocytes, chondrocytes, myotubes, and fibroblasts. Intravenous engraftment of the -labeled cells into recipients of heart transplant resulted in migration of the beta-gal+ cells into the lesions of chronic rejection in the cardiac grafts and homing of the cells to the bone marrow. The majority of beta-gal+ cells present in the allografts exhibited fibroblast phenotypes, and a small number of the cells expressed desmin, indicative of myocyte differentiation. CONCLUSION: MSC vigorously migrated into the site of allograft rejection. This data suggests that they may be attracted to this site to actively participate in tissue repair during chronic rejection. In addition, given the robust migration, the inhibition of MSC differentiation toward fibroblast progeny and induction toward the myocyte lineage may serve as a new strategy for treatment of chronic rejection and allograft tissue repair.

Animals↗

PubMed2003

[Hearing screening for high-risk newborns].

OBJECTIVE: To investigate the morbidity of congenital hearing impairment among high-risk newborns and the relevant pathogenic factors. METHODS: Initial screening of hearing by otoacoustic emission (OAE) was conducted among 208 high-risk newborns, 130 males and 78 females after they were born and the second screening was conducted by OAE was conducted 42 days after those with positive results were examined by auditary brainstem response (ABR). RESULTS: All of the 208 newborns received the initial screening with a screening rate of 100%, and 130 newborns received the second screening with a screening rate of 62.5%. The positive rates in the initial screening and second screening were 34.61% and 7.14% respectively. Six newborns were examined by ABR and 2 of them were diagnoses as with hearing impairment with a prevalence rate of 1.78%. The factors, such as sex, age, and Apgar score affected the initial screening results. CONCLUSION: The most proper time for initial hearing screening is around the 42nd day after birth. High-risk newborns should receive regular test even though they pass the initial screening. A special follow-up system should be constructed for the high-risk newborns.

Evoked Potentials, Auditory, Brain Stem↗

PubMed2003

Inherent instability of plasminogen activator inhibitor type 2 mRNA is regulated by tristetraprolin.

Plasminogen activator inhibitor type 2 (PAI-2) is a serine protease inhibitor that is subject to regulation at the post-transcriptional level. At least two mRNA instability elements reside within the PAI-2 transcript; one in the coding region and another within the 3'-untranslated region (UTR). For the latter, a functional AU-rich motif (ARE) has been identified that provides a binding site for a number of cellular proteins, including the mRNA stability protein, HuR. In this study, we used the yeast three-hybrid system to screen a human leukocyte cDNA library to identify other proteins that associate with the PAI-2 ARE. This screen identified tristetraprolin (TTP) as a PAI-2 mRNA ARE-binding protein. UV cross-linking and immunoprecipitation experiments showed that TTP expressed in HEK293 cells could associate with the PAI-2 ARE in vitro. Co-transfection of plasmids expressing TTP and PAI-2 in HEK293 cells resulted in an increase in the decay rate of PAI-2 mRNA and loss of PAI-2 protein in a process that was dependent upon the PAI-2 3'-UTR. The 29-nt PAI-2 AU-rich element alone was also capable of conferring TTP-dependent mRNA instability to a reporter transcript. The extent of PAI-2 mRNA stability was remarkably sensitive to TTP since TTP-dependent PAI-2 mRNA decay occurred at TTP levels that were below Western blot detection limits. This study identifies TTP as a functional PAI-2 ARE-binding protein that modulates the post-transcriptional regulation of the PAI-2 gene.

3' Untranslated Regions↗

PubMed2003

Smooth muscle cells improve endothelial cell retention on polytetrafluoroethylene grafts in vivo.

OBJECTIVE: We investigated the influence of smooth muscle cells (SMC) on endothelial cell (EC) retention on polytetrafluoroethylene (PTFE) grafts and the effect of SMC seeding on intimal hyperplasia in vivo in a rabbit model. METHODS: Fibronectin-coated PTFE grafts (4 mm diameter) were seeded with either EC alone, SMC alone, or SMC followed 24 hours later by EC. The grafts were connected to an extracorporal aortic shunt for 1 hour or were individually implanted for 1, 30, and 100 days into the infrarenal aorta as an end-to-side bypass graft. The number of retained cells was compared at 1 hour and at 1 day after implantation. Neointimal thickness was measured 30 and 100 days after implantation. RESULTS: After 1-hour exposure to blood flow, EC retention rate was greater (P <.005) if seeded on top of SMC (98% +/- 2%; n = 8) versus being seeded alone (65 +/- 11%; n = 8). SMC retention rate was 95 +/- 5% (n = 8) when seeded alone. Similar cell retention was obtained 1 day after implantation. After 30-day implantation the neointima was thicker in grafts seeded with EC and SMC (282 +/- 136 microm; n = 3) than with EC only (52 +/- 45 microm; n = 3; P <.001). However, the neointimal thickness for dual-cell-seeded grafts (126 +/- 60 microm; n = 3) was not significantly different (P =.09) from EC-seeded grafts (79 +/- 48 microm; n = 3) after 100-day implantation. CONCLUSION: EC retention on PTFE grafts in vivo is improved if seeded over a layer of SMC. Further studies are needed to determine whether overlying EC modulate proliferation of underlying SMC.

Animals↗

PubMed2003

Task-effector asymmetries in a rhythmic continuation task.

Variability in rhythmic movements has been interpreted as a signature of internal or peripheral noise processes. Grounded in an oscillator interpretation, this study hypothesized that period variability and drift arises from the asymmetry between target period and the limb's intrinsic dynamics. Participants synchronized to 7 target periods, swinging 1 of 3 pendulums in a continuation paradigm; 3 periods were longer, 3 shorter, and 1 identical to the preferred period. Results supported 5 predictions: Drift toward the preferred period was observed that scaled with the asymmetry. Variability was lowest for symmetry conditions and increased with the asymmetry. Variability decreased concomitant with the approach toward the preferred period. Periods exponentially approached the preferred period with positive autocorrelations up to 10 cycles.

Adult↗

PubMed2003

Enhanced apoptosis of glioma cell lines is achieved by co-delivering FasL-GFP and TRAIL with a complex Ad5 vector.

Brain tumors (BTs) are among the most malignant forms of human cancer. Unfortunately, current treatments are often ineffective and produce severe side effects. Cytotoxic gene therapy is an alternative treatment strategy, with the potential advantages of reduced toxicity to normal brain tissue. Apoptosis-inducing "death ligands" Fas ligand and TNF-related apoptosis-inducing ligand (TRAIL) are genes with substantial cytotoxic activity in susceptible tumor cells. Here, we compared the effectiveness of Ad vector-mediated delivery of Fas ligand-green fluorescent protein (FasL-GFP) fusion protein, human TRAIL, and both genes simultaneously. We examined a panel of 13 cell lines (eight derived from primary isolates) for susceptibility to Ad5-based vector infection and for sensitivity to FasL- and TRAIL-mediated apoptosis. All cell lines were efficiently transduced, but, as expected, varied in their sensitivity to ligand-induced apoptosis. Generally, sensitivity to FasL-GFP correlated with cell surface FasR levels, but no such correlation was seen for TRAIL and its functional receptors, DR4 and DR5. The vector expressing both FasL-GFP and TRAIL was more effective than either of the single-gene vectors at comparable transduction levels, and it was effective against a broader range of cell lines. In five cell lines, coexpression resulted in apoptosis levels greater than those predicted for strictly additive activity of the two death ligands. We believe that Ad vector-mediated delivery of multiple death ligands may be developed as a potential BT therapy, either alone or in conjunction with surgical resection of the primary tumor.

Adenoviridae↗

PubMed2003

Extracting synonymous gene and protein terms from biological literature.

MOTIVATION: Genes and proteins are often associated with multiple names. More names are added as new functional or structural information is discovered. Because authors can use any one of the known names for a gene or protein, information retrieval and extraction would benefit from identifying the gene and protein terms that are synonyms of the same substance. RESULTS: We have explored four complementary approaches for extracting gene and protein synonyms from text, namely the unsupervised, partially supervised, and supervised machine-learning techniques, as well as the manual knowledge-based approach. We report results of a large scale evaluation of these alternatives over an archive of biological journal articles. Our evaluation shows that our extraction techniques could be a valuable supplement to resources such as SWISSPROT, as our systems were able to capture gene and protein synonyms not listed in the SWISSPROT database.

Abstracting and Indexing↗

PubMed2003

Determination of infectious retrovirus concentration from colony-forming assay with quantitative analysis.

The colony formation assay is the most commonly used titration method for defining the concentration of replication-incompetent murine leukemia virus-derived retroviral vectors. However, titer varies with target cell type and number, transduction time, and concentration of polycation (e.g., Polybrene). Moreover, because most of the viruses cannot encounter target cells due to Brownian motion, their short half-lives, and the requirement for target cell division for activity, the actual infectious retrovirus concentration in the collected supernatant is higher than the viral titer. Here we correlate the physical viral particle concentration with the infectious virus concentration and colony formation titer with the help of a mathematical model. Ecotropic murine leukemia retrovirus supernatant, collected from the GP+E86/LNCX retroviral vector producer cell line, was concentrated by centrifugation and further purified by a sucrose density gradient. The physical concentration of purified viral vectors was determined by direct particle counting with an electron microscope. The concentrations of fresh and concentrated supernatant were determined by a quantitative reverse transcriptase activity assay. Titration of all supernatants by neomycin-resistant colony formation assay was also performed. There were 767 +/- 517 physical viral particles per infectious CFU in the crude viral supernatant. However, the infectious viral concentration determined by mathematical simulation was 143 viral particles per infectious unit, which is more consistent with the concentration determined by particle counting in purified viral solution. Our results suggest that the mathematical model can be used to extract a more accurate and reliable concentration of infectious retrovirus.

3T3 Cells↗

PubMed2003

Widespread expression of arginase I in mouse tissues. Biochemical and physiological implications.

Arginase I (AI), the fifth and final enzyme of the urea cycle, detoxifies ammonia as part of the urea cycle. In previous studies from others, AI was not found in extrahepatic tissues except in primate blood cells, and its roles outside the urea cycle have not been well recognized. In this study we undertook an extensive analysis of arginase expression in postnatal mouse tissues by in situ hybridization (ISH) and RT-PCR. We also compared arginase expression patterns with those of ornithine decarboxylase (ODC) and ornithine aminotransferase (OAT). We found that, outside of liver, AI was expressed in many tissues and cells such as the salivary gland, esophagus, stomach, pancreas, thymus, leukocytes, skin, preputial gland, uterus and sympathetic ganglia. The expression was much wider than that of arginase II, which was highly expressed only in the intestine and kidney. Several co-localization patterns of AI, ODC, and OAT have been found: (a) AI was co-localized with ODC alone in some tissues; (b) AI was co-localized with both OAT and ODC in a few tissues; (c) AI was not co-localized with OAT alone in any of the tissues examined; and (d) AI was not co-localized with either ODC or OAT in some tissues. In contrast, AII was not co-localized with either ODC or OAT alone in any of the tissues studied, and co-localization of AII with ODC and OAT was found only in the small intestine. The co-localization patterns of arginase, ODC, and OAT suggested that AI plays different roles in different tissues. The main roles of AI are regulation of arginine concentration by degrading arginine and production of ornithine for polyamine biosynthesis, but AI may not be the principal enzyme for regulating glutamate biosynthesis in tissues and cells.

Animals↗