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Biomedical subjects

Yan Gong

Publications and source records attributed to Yan Gong.

At least 19 recordsLinked to original sources
PubMed2006

Relation of beta(2)-adrenoceptor haplotype to risk of death and heart transplantation in patients with heart failure.

Heart failure (HF) is characterized by neurohormonal activation of the sympathetic nervous and renin-angiotensin systems. Genetic polymorphisms in these systems could alter the prognosis in HF. We hypothesized the genetic polymorphisms in the sympathetic nervous and renin-angiotensin systems are associated with adverse outcomes, defined as death or heart transplantation in patients with HF. A total of 227 patients with HF were enrolled from a tertiary care clinic and followed for outcomes for < or =4 years. Eight polymorphisms in 6 genes were genotyped: beta(1)-adrenergic receptor (ADRB1, S49G, R389G), beta(2)-adrenergic receptor (ADRB2, G16R, Q27E), alpha(2c)-adrenergic receptor (ADRA2C, insertion/deletion 322-325), angiotensinogen (AGT, M235T), angiotensin receptor type 1 (AGTR1, 1166A>C), and angiotensin-converting enzyme (ACE, insertion/deletion in intron 16). Most patients were treated according to consensus guidelines. Male gender (hazard ratio 2.24, 95% confidence interval 1.27 to 3.94), higher New York Heart Association functional class (hazard ratio 2.54, 95% confidence interval 1.84 to 3.52), and 2 copies of ADRB2 Arg16Gln27 haplotype (hazard ratio 1.91, 95% confidence interval 1.09 to 3.36) increased the risk of adverse outcomes. In contrast, a higher serum sodium level (hazard ratio 0.91, 95% confidence interval 0.86 to 0.97) and higher creatinine clearance (hazard ratio 0.99, 95% confidence interval 0.98 to 0.99) decreased the risk of adverse outcomes. None of the other genotypes/haplotypes were associated with adverse outcomes. In conclusion, ADRB2 Arg16Gln27 haplotype may significantly increase the risk of adverse outcomes in patients with HF receiving contemporary HF pharmacotherapy.

DNA↗
PubMed2006

Memory-related deficits following selective hippocampal expression of Swedish mutation amyloid precursor protein in the rat.

The gene encoding for the Swedish double mutation (K595N/M596L) of amyloid precursor protein (APP695Swe) was expressed bilaterally in adult rat hippocampus to determine its long-term effects on memory-related behavior as well as amyloid deposition. Recombinant adeno-associated viral serotype 2 (rAAV2) vectors were injected that contained either non-expressing DNA or cDNA encoding for APP695Swe under control of a chicken beta actin/cytomegalovirus promoter/enhancer. Immunolabeling human APP with the antibody 6E10 was observed throughout the cytoplasm of aspiny and, to a lesser extent, spine-bearing hippocampal neurons 6 and 12 months post-injection of the APP695Swe but not control vector. Abeta1-42 immunolabeling was identified in unusual immunoreactive objects within the hilus of the dentate gyrus and in the granule cell layer, proximal to the injection site. At 12 months post-transduction, rats that received the APP695Swe gene also demonstrated significant deficits in the acquisition and probe components of the spatial-memory-related Morris water task compared to control animals. These behavioral deficits occurred in the absence of any amyloid plaques, gliosis, or FluoroJade labeling of dying neurons. In conclusion, prolonged and localized APP695Swe expression in hippocampal neurons is sufficient to produce memory deficits without plaque formation or neuronal loss.

Alzheimer Disease↗
PubMed2006

Effect of hepatitis B immunisation in newborn infants of mothers positive for hepatitis B surface antigen: systematic review and meta-analysis.

OBJECTIVE: To evaluate the effects of hepatitis B vaccine and immunoglobulin in newborn infants of mothers positive for hepatitis B surface antigen. DESIGN: Systematic review and meta-analysis of randomised clinical trials. DATA SOURCES: Electronic databases and hand searches. REVIEW METHODS: Randomised clinical trials were assessed for methodological quality. Meta-analysis was undertaken on three outcomes: the relative risks of hepatitis B occurrence, antibody levels to hepatitis B surface antigen, and adverse events. RESULTS: 29 randomised clinical trials were identified, five of which were considered high quality. Only three trials reported inclusion of mothers negative for hepatitis B e antigen. Compared with placebo or no intervention, vaccination reduced the occurrence of hepatitis B (relative risk 0.28, 95% confidence interval 0.20 to 0.40; four trials). No significant difference in hepatitis B occurrence was found between recombinant vaccine and plasma derived vaccine (1.00, 0.71 to 1.42; four trials) and between high dose versus low dose vaccine (plasma derived vaccine 0.97, 0.55 to 1.68, three trials; recombinant vaccine 0.78, 0.31 to 1.94, one trial). Compared with placebo or no intervention, hepatitis B immunoglobulin or the combination of plasma derived vaccine and hepatitis B immunoglobulin reduced hepatitis B occurrence (immunoglobulin 0.50, 0.41 to 0.60, one trial; vaccine and immunoglobulin 0.08, 0.03 to 0.17, three trials). Compared with vaccine alone, vaccine plus hepatitis B immunoglobulin reduced hepatitis B occurrence (0.54, 0.41 to 0.73; 10 trials). Hepatitis B vaccine and hepatitis B immunoglobulin seem safe, but few trials reported adverse events. CONCLUSION: Hepatitis B vaccine, hepatitis B immunoglobulin, and vaccine plus immunoglobulin prevent hepatitis B occurrence in newborn infants of mothers positive for hepatitis B surface antigen.

Combined Modality Therapy↗
PubMed2006

Different immunoaffinity fractionation strategies to characterize the human plasma proteome.

Plasma proteins may often serve as indicators of disease and are a rich source for biomarker discovery. However, the intrinsic large dynamic range of plasma proteins makes the analysis very challenging because a large number of low abundance proteins are often masked by a few high abundance proteins. The use of prefractionation methods, such as depletion of higher abundance proteins before protein profiling, can assist in the discovery and detection of less abundant proteins that may ultimately prove to be informative biomarkers. But there are few studies on comprehensive investigation of the proteins both in the fractions depleted and remainder. In the present study, two different immunoaffinity fractionation columns for the top-6 or the top-12 proteins in plasma were investigated and both the proteins in column-bound and flow-through fractions were subsequently analyzed. A two-dimensional peptide separation strategy, utilizing chromatographic separation techniques, combined with tandem mass spectrometry (MS/MS) was employed for proteomic analysis of the four fractions. Using the established HUPO PPP criteria, a total of 2401 unique plasma proteins were identified. The Multiple Affinity Removal System yielded 921 and 725 unique proteins from the flow-through and bound fractions, respectively, whereas the Seppro MIXED 12 column yielded identification of 897 and 730 unique proteins from the flow-through and bound fractions, respectively. When more stringent criteria, based on searching against the reversed database, were implemented, 529 unique proteins were identified from the four fractions with the confidence in peptide identification increased from 73.6% to 99%. To determine whether the presence of nontarget proteins in the immunoaffinity-bound fraction could be attributed to their interaction with high abundance proteins, co-immunoprecipitation analysis with an antibody to human plasma albumin was performed, which resulted in an identification of 40 unique proteins from the coimmunoprecipitate with the more stringent criteria. This study illustrated that combining the column-bound and flow-through fractions from immunoaffinity separation affords more extensive profiling of the protein content of human plasma. The presence of nontarget proteins in the column-bound fractions may be induced by their binding to the higher abundance proteins targeted by the immunoaffinity column.

Amino Acid Sequence↗
PubMed2006

Actin binding activity of subunit B of vacuolar H+-ATPase is involved in its targeting to ruffled membranes of osteoclasts.

UNLABELLED: Adeno-associated virus was used to transduce primary mouse osteoclasts with the B1 isoform of vacuolar H(+)-ATPase. B1, which is not normally expressed in osteoclasts, was correctly targeted to ruffled membranes of resorbing osteoclasts. Mutant subunit B1 that lacked a functional actin-binding site did not accumulate in ruffled membranes. INTRODUCTION: The B1 "kidney" and B2 "brain" isoforms of subunit B of vacuolar H(+)-ATPase (V-ATPase) have actin binding sites that mediate interactions between the intact enzyme and filamentous-actin. Accumulating data support the hypothesis that the actin binding activity in subunit B is required for targeting of V-ATPases to the ruffled plasma membrane of osteoclasts. This study was designed to directly test this hypothesis. MATERIALS AND METHODS: Osteoclasts express B2, but not B1. Adeno-associated virus vectors were used to transduce mouse osteoclasts with wildtype B1 or B1(mut), a full-length B subunit that contained minor alterations that disrupted actin-binding activity. Immunofluorescence was performed using polyclonal antibodies specific for subunit E, B2, and B1 of V-ATPase. Immunoprecipitations were performed using an anti-E subunit antibody. Microfilaments were detected with phalloidin and actin rings were stained with phalloidin or anti-vinculin antibodies. Images were collected using a confocal microscope. RESULTS: Immunoprecipitations of transduced osteoclasts suggested that both B1 and B1(mut) assembled with endogenous V-ATPase subunits to form intact enzyme in osteoclasts. Both B1 and B1(mut) were localized like endogenous V-ATPase subunits in unactivated osteoclasts. Wildtype B1 associated with the detergent-insoluble cytoskeleton and was transported to ruffled membranes of resorbing osteoclasts. In contrast, B1(mut) failed to associate with the actin cytoskeleton and was not transported efficiently to ruffled membranes. CONCLUSIONS: The B1 isoform of B subunit contains the necessary information for targeting to the ruffled membranes of osteoclasts even though it is not normally expressed in osteoclasts. The actin binding activity of B1 is involved in proper ruffled membrane targeting.

Actins↗
PubMed2006

[Temperature-dependent optical activity and birefringence study of D-alanine single crystal].

The measurement of the anisotropy of optical acitivity and birefringence is one of the most important clues to studying physical properties of a biaxial crystal of D-alanine. In order to investigate a second-order phase transition predicted by A. Salam between two states of D-alanine, the behavior of birefringence and optical activity is useful for the phenomenological approach to the transition mechanism. The optical activity as a peculiar quantity can respond to the modulation of the crystal lattice and to the change in the bonding nature of constituent atoms. In the present paper, the authors use the PEM-90 photoelastic modulator to study the conformation change of D-alanine at the temperature ranging from 220 to 290 K. The temperature dependence of I(2f)/I(dc) showed that the conformation of D-alanine molecule in single crystal changed around 250 K. The obtained results provide an obvious evidence of optical rotation phase transition predicted by Salam.

Alanine↗
PubMed2006

[Raman scattering study of DL-alanine].

Studies of Raman vibration spectra are useful to obtaining information on biomolecular crystals. The cell dimensions of the L- and DL-alanine crystals are nearly identical, and both structures belong to the orthorhombic system, but the space group is P2(1) 2(1) 2(1) for the L-isomer, and Pna2(1) for the racemate crystal. The Raman spectrum of L-alanine has been measured by many authors. The present work is focusing on the Raman scattering study of DL-alanine powder. Based on the analysis of the differences between DL-alanine and L-alanine Raman spectra, the authors obtained indispensable information on hydrogen bond and the motion of the molecular conformation in alanine crystals.

Alanine↗
PubMed2006

[Determination of egg-yolk phosphatidylcholine by normal-phase high performance liquid chromatography with evaporative light scattering detection].

A method for the determination of egg-yolk phosphatidylcholine by normal-phase high performance liquid chromatography (NP-HPLC) with evaporative light scattering detection (ELSD) was developed. Yolk phosphatidylcholine was successfully separated on a Nova-Pak Silica 60A column (3.9 mm i.d. x 150 mm, 4 microm), using hexane-isopropanol-water containing 3% acetic acid (35: 65: 8, v/v/v) as mobile phase at a flow rate of 1.0 mL/min. The drift tube temperature and air carrier gas pressure of the ELSD were set at 50 degrees C and 350 kPa, respectively. The linear detection range was 0.16 - 1.61 g/L (r2 = 0.997 9) and the limit of detection (LOD) was 0.64 microg with excellent relative standard deviation (RSD) of 3.2% (n = 5). The recovery was in the range of 98.2% - 128.2%. The results indicated that this method is accurate, rapid, simple and reproducible, and thus suitable for the analysis of egg-yolk phosphatidylcholine in real samples.

English Abstract↗
PubMed2005

Comparison of alternative analytical techniques for the characterisation of the human serum proteome in HUPO Plasma Proteome Project.

Based on the same HUPO reference specimen (C1-serum) with the six proteins of highest abundance depleted by immunoaffinity chromatography, we have compared five proteomics approaches, which were (1) intact protein fractionation by anion-exchange chromatography followed by 2-DE-MALDI-TOF-MS/MS for protein identification (2-DE strategy); (2) intact protein fractionation by 2-D HPLC followed by tryptic digestion of each fraction and microcapillary RP-HPLC/microESI-MS/MS identification (protein 2-D HPLC fractionation strategy); (3) protein digestion followed by automated online microcapillary 2-D HPLC (strong cation-exchange chromatography (SCX)-RPC) with IT microESI-MS/MS; (online shotgun strategy); (4) same as (3) with the SCX step performed offline (offline shotgun strategy) and (5) same as (4) with the SCX fractions reanalysed by optimised nanoRP-HPLC-nanoESI-MS/MS (offline shotgun-nanospray strategy). All five approaches yielded complementary sets of protein identifications. The total number of unique proteins identified by each of these five approaches was (1) 78, (2) 179, (3) 131, (4) 224 and (5) 330 respectively. In all, 560 unique proteins were identified. One hundred and sixty-five proteins were identified through two or more peptides, which could be considered a high-confidence identification. Only 37 proteins were identified by all five approaches. The 2-DE approach yielded more information on the pI-altered isoforms of some serum proteins and the relative abundance of identified proteins. The protein prefractionation strategy slightly improved the capacity to detect proteins of lower abundance. Optimising the separation at the peptide level and improving the detection sensitivity of ESI-MS/MS were more effective than fractionation of intact proteins in increasing the total number of proteins identified. Overall, electrophoresis and chromatography, coupled respectively with MALDI-TOF/TOF-MS and ESI-MS/MS, identified complementary sets of serum proteins.

Blood Proteins↗
PubMed2005

Colchicine for primary biliary cirrhosis: a Cochrane Hepato-Biliary Group systematic review of randomized clinical trials.

OBJECTIVES: Colchicine is used for patients with primary biliary cirrhosis due to its immunomodulatory and antifibrotic potential. The results from randomized clinical trials have, however, been inconsistent. We conducted a systematical review to evaluate the effect of colchicine for primary biliary cirrhosis. METHODS: We identified randomized clinical trials comparing colchicine with placebo/no intervention. We analyzed effects by fixed and random effects model. We investigated heterogeneity by subgroup and sensitivity analyses. RESULTS: We included 10 trials involving 631 patients, four of which were high-quality trials. No significant differences were detected between colchicine and placebo/no intervention regarding mortality (relative risk (RR), 1.21; 95% confidence interval (CI), 0.71-2.06), mortality or liver transplantation (RR = 1.00; 95% CI, 0.67-1.49), liver complications, liver biochemical variables, liver histology, or adverse events. Regarding mortality, an extreme case analysis favoring colchicine did not demonstrate beneficial effects of colchicine, whereas an extreme case analysis favoring placebo/no intervention demonstrated a detrimental effect of colchicine (RR = 2.28; 95% CI, 1.17-4.44). The number of patients without improvement of pruritus significantly decreased in the colchicine group (RR = 0.75; 95% CI, 0.65-0.87). However, this estimate was based on only 156 patients from three trials. CONCLUSIONS: There is insufficient evidence to support the use of colchicine for patients with primary biliary cirrhosis. As we are unable to exclude a risk of increased mortality, we recommend to use colchicine only in randomized clinical trials.

Colchicine↗
PubMed2005

[Analysis of part of M gene and genotyping for M segment of hantavirus detected from HFRS patients' sera in Qingdao region during 2000 - 2003].

OBJECTIVE: To study the molecular epidemiological characteristics of hantavirus seen during 2000-2003 in Qingdao region of Shandong province. METHODS: Sera were collected from 64 patients with hemorrhagic fever with renal syndrome (HFRS) and viral RNA was extracted from the sera. HTN and SEO universal primers were designed as outer primers and HTN and SEO specific primers as inner primers. G1 gene region of M segment from hantavirus was amplified by using RT-nest-PCR for sequencing. The data of nucleotide sequences were analyzed by DNA star software. RESULTS: Six cases were positive by HTN specific primer of total cases (9%); 25 of 64 cases by SEO specific primer (39%); total positive rate was 48%. In general, SEO type was a prevalent type of hantavirus in Qingdao region. The variation of the nucleotide sequences among SEO viruses (nucleotide sequence divergence ranged from 0.3% approximately 8.9%) was lower than that among HTN type (nucleotide sequence divergence ranged from 2.6% approximately 11.2% ). CONCLUSION: Majority of hantavirus found in Qingdao region belonged to SEO type and still a few strains belonged to HTN type. Most of the HTN viruses were detected in Jiaonan county.

China↗
PubMed2004

Evidence for serine/threonine and histidine kinase activity in the tobacco ethylene receptor protein NTHK2.

Ethylene plays important roles in plant growth, development, and stress responses. Two ethylene receptors, ETR1 from Arabidopsis and NTHK1 from tobacco (Nicotiana tabacum), have been found to have His kinase (HK) activity and Ser/Thr kinase activity, respectively, although both show similarity to bacterial two-component HK. Here, we report the characterization of another ethylene receptor homolog gene, NTHK2, from tobacco. This gene also encodes a HK-like protein and is induced by dehydration and CaCl(2) but not significantly affected by NaCl and abscisic acid treatments. The biochemical properties of the yeast (Schizosaccharomyces pombe)-expressed NTHK2 domains were further characterized. We found that NTHK2 possessed Ser/Thr kinase activity in the presence of Mn(2+) and had HK activity in the presence of Ca(2+). Several lines of evidence supported this conclusion, including hydrolytic stability, phosphoamino acid analysis, mutation, deletion, and substrate analysis. These properties have implications in elucidation of the complexity of the ethylene signal transduction pathway and understanding of ethylene functions in plants.

Abscisic Acid↗
PubMed2004

Recombinant adeno-associated virus serotype 2 effectively transduces primary rat brain astrocytes and microglia.

Recombinant adeno-associated virus-2 (rAAV2) under control of the chicken beta actin promoter/truncated CMV enhancer (CBA) was investigated for its ability to transduce primary cultures of rat brain neurons, microglia and astrocytes. This vector was highly effective in all three cell types in heparin-sensitive manners (astrocytes, microglia and neurons transduced by >98%, 75%, and 95%, respectively). However, astrocytes co-cultured with neurons were not transduced. rAAV2/CBA is an important new method for genetic manipulation of brain cells, though this may be modulated by interactions among cell types.

Animals↗
PubMed2004

[Preliminary study on preparation and pharmaceutic features of adrimycin-loaded human serum albumin microspheres].

OBJECTIVE: To prepare adrimycin-loaded human serum albumin microspheres(ADR-HSA-MS) and to study its pharmaceutic properties and in vitro cytotoxicity. METHODS: ADR-HSA-MS, consisting of ADR and HSA, were prepared by emulsion heating solidification method and its morphology was observed by optical microscopy and scanning electron microscopy. Pepsin digestion method was used for determining drug loading of ADR-HSA-MS and membrane diffusion technique for detection of in vitro release of ADR from the microspheres. MTT colorimetric assay was used to determine cytotoxicity of ADR-HSA-MS for human hepatoma SMMC-7721 cell line. RESULTS: ADR-HSA-MS looked like smooth red spheres with an average diameter of 1.2 microns and had an apparent drug-loading of 2.73% or an effective drug-loading of 1.69%. Its peak of the accumulated drug-releasing fraction was 65%, and 50% of ADR releasing from the MS would take five days, which suggested a slow release of ADR from the albumin microspheres. ADR-HSA-MS exerted remarkable cytotoxicity to human hepatoma SMMC-7721 cells with dose-dependence at a range of ADR concentration from 0.3 microgram/ml to 2.5 micrograms/ml when incubated with the target cells for four days. Its killing curve was similar to that of free ADR. CONCLUSION: Emulsion heating solidification method could be used for preparation of adrimycin-loaded human serum albumin microspheres with sustained release property.

Antibiotics, Antineoplastic↗
PubMed2004

[Method to measure spectrum intensity from laser plasma soft X-ray source].

This paper presents a method to detect and measure spectrum intensity from a laser plasma soft X-ray source. A Channel Electron Multiplier (CEM) and a calibrated silicon photodiode were used as detectors in this method, the former is a nonstandard detector and the latter is a standard one. Charge-sensitive preamplifiers were used for measuring total charges generated by detectors, and a monochromator with high resolution was employed as the spectrometer. The formulae to calculate spectrum intensity from laser plasma soft X-ray source was given, based on the known grating efficiency of the monochromator, CEM's gain and responsivity of the silicon photodiode to photons.

Equipment Design↗
PubMed2003

[Experimental investigation of laser plasma soft X-ray source with gas target].

This paper describes a debris-free laser plasma soft X-ray source with a gas target, which has high operating frequency and can produce strong soft X-ray radiation. The valve of this light source is drived by a piezoelectrical ceramic whose operating frequency is up to 400 Hz. In comparison with laser plasma soft X-ray sources using metal target, the light source is debris-free. And it has higher operating frequency than gas target soft X-ray sources whose nozzle is controlled by a solenoid valve. A channel electron multiplier (CEM) operating in analog mode is used to detect the soft X-ray generated by the laser plasma source, and the CEM's output is fed to to a charge-sensitive preamplifier for further amplification purpose. Output charges from the CEM are proportional to the amplitude of the preamplifier's output voltage. Spectra of CO2, Xe and Kr at 8-14 nm wavelength which can be used for soft X-ray projection lithography are measured. The spectrum for CO2 consists of separate spectral lines originate mainly from the transitions in Li-like and Be-like ions. The Xe spectrum originating mainly from 4d-5f, 4d-4f, 4d-6p and 4d-5p transitions in multiply charged xenon ions. The spectrum for Kr consists of separate spectral lines and continuous broad spectra originating mainly from the transitions in Cu-, Ni-, Co- and Fe-like ions.

English Abstract↗