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Bing Xu

Publications and source records attributed to Bing Xu.

At least 19 recordsLinked to original sources
PubMed2024

Misregulation of bromotyrosine compromises fertility in male Drosophila.

Biological regulation often depends on reversible reactions such as phosphorylation, acylation, methylation, and glycosylation, but rarely halogenation. A notable exception is the iodination and deiodination of thyroid hormones. Here, we report detection of bromotyrosine and its subsequent debromination during Drosophila spermatogenesis. Bromotyrosine is not evident when Drosophila express a native flavin-dependent dehalogenase that is homologous to the enzyme responsible for iodide salvage from iodotyrosine in mammals. Deletion or suppression of the dehalogenase-encoding condet (cdt) gene in Drosophila allows bromotyrosine to accumulate with no detectable chloro- or iodotyrosine. The presence of bromotyrosine in the cdt mutant males disrupts sperm individualization and results in decreased fertility. Transgenic expression of the cdt gene in late-staged germ cells rescues this defect and enhances tolerance of male flies to bromotyrosine. These results are consistent with reversible halogenation affecting Drosophila spermatogenesis in a process that had previously eluded metabolomic, proteomic, and genomic analyses.

Animals↗
PubMed2006

Carbon monoxide inhalation protects lung from lipopolysaccharide-induced injury in rat.

Carbon monoxide (CO), a metabolite of heme catalysis by heme oxygenase (HO), has been proposed to have anti-oxidative, anti-inflammatory and anti-apoptotic functions. Lipopolysaccharide (LPS)-induced lung injury (LI) is characterized by oxidative stress, inflammatory reaction and excessive pulmonary cell apoptosis. So we supposed that CO might have protection against LI. LI in rats was induced by intravenous injection of LPS (5 mg/kg). To observe the effect of CO inhalation, LI rats were exposed to 2.5 x 10(-4) (V/V) CO for 3 h. CO-induced changes of lung oxidative stress parameters, inflammatory cytokines, cell apoptosis, HO-1 expression and histology were examined. Results revealed that expressions of the tumor necrosis factor-alpha (TNF-alpha) and interlukin-6 (IL-6), activities of maleic dialdehyde (MDA) and myeloperoxidase (MPO), and cell apoptosis in LPS injection + CO inhalation group were (0.91+/-0.25) pg/mg protein, (0.64+/-0.05) pg/mg protein, (1.02+/-0.23) nmol/mg protein, (7.18+/-1.62) U/mg protein and (1.60+/-0.34)%, respectively, significantly lower than the corresponding values in LI group [(1.48+/-0.23) pg/mg protein, (1.16+/-0.26) pg/mg protein, (1.27+/-0.33) nmol/mg protein, (8.16+/-1.49) U/mg protein and (3.18+/-0.51) %, P<0.05]. Moreover, CO inhalation obviously increased the expressions of HO-1 and interlukin-10 (IL-10) and activity of superoxide dismutase (SOD) [(5.43+/-0.92), (0.26+/-0.07) pg/mg protein and (60.09+/-10.21) U/mg protein in LPS injection + CO inhalation group vs (3.08+/-0.82), (0.15+/-0.03) pg/mg protein and (50.98+/-6.88) U/mg protein in LI group, P<0.05]. LI was attenuated by CO inhalation. Our study demonstrates that inhalation of low concentration of CO protects lung against LPS-induced injury via anti-oxidant, anti-inflammation, anti-apoptosis and up-regulation of HO-1 expression.

Administration, Inhalation↗
PubMed2006

A biocompatible method of decorporation: bisphosphonate-modified magnetite nanoparticles to remove uranyl ions from blood.

We report on the use of bisphosphonate to functionalize Fe3O4 magnetic nanoparticles via dopamine (DA) linkage. Using tetraethyl-3-aminopropane-1,1-bisphosphonate (BP) as the functional molecule, we created a system with an Fe3O4-DA-BP nanostructure, which possesses high specificity for removing uranyl ions from water or blood. This work demonstrates that magnetic nanoparticles, combined with specific receptor-ligand interactions, promise a sensitive and rapid platform for the detection, recovery, and decorporation of metal toxins from biological environment.

Biocompatible Materials↗
PubMed2006

Partial rescue of defects in Cited2-deficient embryos by HIF-1alpha heterozygosity.

Hypoxia inducible factor-1 (HIF-1) initiates key cellular and tissue responses to physiological and pathological hypoxia. Evidence from in vitro and structural analyses supports a critical role for Cited2 in down-regulating HIF-1-mediated transcription by competing for binding with oxygen-sensitive HIF-1alpha to transcriptional co-activators CBP/p300. We previously detected elevated expression of HIF-1 target genes in Cited2(-/-) embryonic hearts, indicating that Cited2 inhibits HIF-1 transactivation in vivo. In this study, we show for the first time that highly hypoxic cardiac regions in mouse embryos corresponded to the sites of defects in Cited2(-/-) embryos and that defects of the outflow tract, interventricular septum, cardiac vasculature, and hyposplenia were largely rescued by HIF-1alpha haploinsufficiency. The hypoxia of the outflow tract and interventricular septum peaked at E13.5 and dissipated by E15.5 in wild-type hearts, but persisted in E15.5 Cited2(-/-) hearts. The persistent hypoxia and abnormal vasculature in the myocardium of interventricular septum in E15.5 Cited2(-/-) hearts were rescued with decreased HIF-1alpha gene dosage. Accordingly, mRNA levels of HIF-1-responsive genes were reduced in Cited2(-/-) embryonic hearts by HIF-1alpha heterozygosity. These findings suggest that a precise level of HIF-1 transcriptional activity critical for normal development is triggered by differential hypoxia and regulated through feedback inhibition by Cited2.

Animals↗
PubMed2006

Differential effects of progestogens, by type and regimen, on estrogen-metabolizing enzymes in human breast cancer cells.

OBJECTIVES: To investigate the in vitro effects of five progestogens commonly used in hormone replacement therapy (HRT) on estrogen-metabolizing enzymes in human breast cancer cells. METHODS: The human hormone-dependent breast cancer cell lines T47D, MCF-7, and MCF-7aro were cultured with estradiol (E(2)) and progestogens. The mRNA levels of estrogen-metabolizing enzymes were determined by RT-PCR or Northern blot, and enzyme activities by radiolabeled substrates. Cell proliferation was measured by bromodeoxyuridine incorporation. In vitro models for continuous combined regimen (CCR) and sequential combined regimen (SCR) were established to mimic the in vivo conditions of HRT. RESULTS: Medroxyprogesterone acetate (MPA) plus E(2) (10(-8)M) stimulated the mRNA levels and activities of estrogen-activating enzymes aromatase (at 10(-8)M MPA), 17beta-hydroxysteroid dehydrogenase type 1 (17betaHSD1) (at 10(-6)M), and sulfatase (at 10(-8) to 10(-6)M) compared to E(2) only. Progesterone also stimulated enzyme activity, but to a lower magnitude. Levonorgestrel, norethindrone, and dienogest showed no enzyme stimulation. The estrogen-inactivating enzymes 17beta-hydroxysteroid dehydrogenase type 2 and sulfotransferase were not affected by any of the progestogens tested. However, all the progestogens (at 10(-8) to 10(-6)M) inhibited E(2)-stimulated cell proliferation. While increased aromatase and 17betaHSD1 activities were observed in the CCR model, no significant enzyme stimulation was observed in the SCR model. CONCLUSIONS: The present study suggested that progestogens exert different actions on estrogen-metabolizing enzymes in breast cancer cells dependent on the specific progestogen and regimen used. Further studies are needed to elucidate whether MPA, a progestogen currently used in HRT, leads to a higher risk of breast cancer development than other progestogens.

17-Hydroxysteroid Dehydrogenases↗
PubMed2006

Photophysical properties of novel lanthanide (Tb3+, Dy3+, Eu3+) complexes with long chain para-carboxyphenol ester p-L-benzoate (L=dodecanoyloxy, myristoyloxy, palmitoyloxy and stearoyloxy).

In this paper, a series of 12 binary luminescent lanthanide coordination compounds with long chain p-carboxyphenol ester were assembled. Both elemental analysis and infrared spectroscopy allowed to determine the complexes formula: LnL3, where Ln=Tb, Dy, Eu; L=p-dodecanoyloxybenzoate (12-OBA), p-myristoyloxybenzoate (14-OBA), p-palmitoyloxybenzoate (16-OBA) and p-stearoyloxybenzoate (18-OBA), respectively. The photophysical properties of these complexes were studied in detail with various of spectroscopies such as ultraviolet-visible absorption spectra, low temperature phosphorescence spectra and fluorescent spectra. The ultraviolet-visible absorption spectra showed that some bands shift with the different chain length of p-carboxyphenol ester. From the low temperature phosphorescent emission, the triplet state energies for these four ligands were determined to be around 24,242 cm-1 (12-OBA), 24,612 cm-1 (14-OBA), 24,084 cm-1 (16-OBA) and 24,125 cm-1 (18-OBA), respectively, suggesting they are suitable for the sensitization of the above lanthanide ions, especially for Tb3+ and Dy3+. The fluorescence excitation and emission spectra for these lanthanide complexes of the four ligands take agreement with the above predict from energy match.

Benzoates↗
PubMed2006

Spatial analysis of hemorrhagic fever with renal syndrome in China.

BACKGROUND: Hemorrhagic fever with renal syndrome (HFRS) is endemic in many provinces with high incidence in mainland China, although integrated intervention measures including rodent control, environment management and vaccination have been implemented for over ten years. In this study, we conducted a geographic information system (GIS)-based spatial analysis on distribution of HFRS cases for the whole country with an objective to inform priority areas for public health planning and resource allocation. METHODS: Annualized average incidence at a county level was calculated using HFRS cases reported during 1994-1998 in mainland China. GIS-based spatial analyses were conducted to detect spatial autocorrelation and clusters of HFRS incidence at the county level throughout the country. RESULTS: Spatial distribution of HFRS cases in mainland China from 1994 to 1998 was mapped at county level in the aspects of crude incidence, excess hazard and spatial smoothed incidence. The spatial distribution of HFRS cases was nonrandom and clustered with a Moran's I = 0.5044 (p = 0.001). Spatial cluster analyses suggested that 26 and 39 areas were at increased risks of HFRS (p < 0.01) with maximum spatial cluster sizes of < or = 20% and < or = 10% of the total population, respectively. CONCLUSION: The application of GIS, together with spatial statistical techniques, provide a means to quantify explicit HFRS risks and to further identify environmental factors responsible for the increasing disease risks. We demonstrate a new perspective of integrating such spatial analysis tools into the epidemiologic study and risk assessment of HFRS.

China↗
PubMed2006

Double-deformable-mirror adaptive optics system for phase compensation.

Two kinds of algorithm for an adaptive optics (AO) system that uses two deformable mirrors (DMs), one with large stroke and the other with high spatial frequency, to correct different aberrations are described. The algorithms are based on modal method and direction-gradient method, respectively. Numerical simulations for the algorithms have been made. The simulation results indicate that the two DMs in the AO system can correct different aberrations with different characteristics, and the closed-loop performance of a double-DM AO system will be almost the same as that of an AO system that uses a single DM with an ideal stroke.

Journal Article↗
PubMed2006

Using a kinase/phosphatase switch to regulate a supramolecular hydrogel and forming the supramolecular hydrogel in vivo.

We have designed and synthesized a new hydrogelator Nap-FFGEY (1), which forms a supramolecular hydrogel. A kinase/phosphatase switch is used to control the phosphorylation and dephosphorylation of the hydrogelator and to regulate the formation of supramolecular hydrogels. Adding a kinase to the hydrogel induces a gel-sol phase transition in the presence of adenosine triphosphates (ATP) because the tyrosine residue is converted into tyrosine phosphate by the kinase to give a more hydrophilic molecule of Nap-FFGEY-P(O)(OH)(2) (2); treating the resulting solution with a phosphatase transforms 2 back to 1 and restores the hydrogel. Electron micrographs of the hydrogels indicate that 1 self-assembles into nanofibers. Subcutaneous injection of 2 in mice shows that 80.5 +/- 1.2% of 2 turns into 1 and results in the formation of the supramolecular hydrogel of 1 in vivo. This simple biomimetic approach for regulating the states of supramolecular hydrogels promises a new way to design and construct biomaterials.

Adenosine Triphosphate↗
PubMed2006

Improved rate control for electron-beam evaporation and evaluation of optical performance improvements.

A new deposition-rate-control and electron-beam-gun (e-gun) strategy was developed that significantly reduces the growth-rate variations for e-beam-deposited SiO2 coatings. The resulting improvements in optical performance are evaluated for multilayer bandpass filters. The adverse effect of uneven silica-source depletion on coating spectral performances during long deposition runs is discussed.

Journal Article↗
PubMed2006

Biofunctional magnetic nanoparticles for protein separation and pathogen detection.

Recent successful syntheses of monodispersed magnetic nanoparticles have offered a unique opportunity to control and probe biological interactions using magnetic force. This paper highlights a general strategy to generate biofunctional magnetic nanoparticles, illustrates applications for these nanoparticles in protein separation and pathogen detection, and analyzes the high sensitivity and high selectivity achieved by this system.

Infections↗
PubMed2006

[The mechanisms of carbon monoxide inhalation on the apoptosis of pulmonary cells in rats with acute lung injury induced by lipopolysaccharide].

OBJECTIVE: To investigate the effects of carbon monoxide (CO) inhalation on the apoptosis of pulmonary cells in rats with acute lung injury (ALI) induced by lipopolysaccharide (LPS) and to investigate its mechanisms. METHODS: Eighteen male SD rats were randomly divided into three groups. The ALI group received LPS 5 mg/kg intravenously, while the control group received normal saline, and the CO inhalation group received an inhalation of 2.5 x 10(-4) CO (V/V) after ALI induced by LPS 5 mg/kg. The animals were sacrificed by exsanguinations and lung tissue was harvested at 3 h of observation for determination of the heme oxygenase-1 (HO-1) mRNA with semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), the level of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and IL-10 with enzyme-linked immunosorbent assay (ELISA) and the maleic dialdehyde (MDA) concentration, myeloperoxidase (MPO) and superoxide dismutase (SOD) activity with chemical methods. The extent of cell apoptosis was observed by using the flow cytometric method. RESULTS: The change of the levels of HO-1 mRNA, TNF-alpha, IL-6, IL-10, MDA, MPO, SOD and apoptotic cells of the ALI group was significant as compared with the control group [1.002 +/- 0.004, (0.47 +/- 0.06) pg/mg prot, (0.49 +/- 0.12) pg/mg prot, (0.42 +/- 0.08) pg/mg prot, (0.79 +/- 0.14) nmol/mg prot, (6.0 +/- 1.0) U/mg prot, (74 +/- 7) U/mg prot, (0.12 +/- 0.03)%, P < 0.05 or < 0.01], and lung injury was severe. The levels of TNF-alpha, IL-6, MDA, MPO, and apoptotic cells of the CO inhalation group [(0.91 +/- 0.25) pg/mg prot, (0.64 +/- 0.05) pg/mg prot, (1.02 +/- 0.23) nmol/mg prot, (7.2 +/- 1.6) U/mg prot, (1.60 +/- 0.34)%] were decreased, while HO-1, IL-10 and SOD expression [5.433 +/- 0.921, (0.26 +/- 0.07) pg/mg prot, (60 +/- 10) U/mg prot] were increased compared with the ALI group [(1.48 +/- 0.23) pg/mg prot, (1.16 +/- 0.26) pg/mg prot, (1.27 +/- 0.33) nmol/mg prot, (8.2 +/- 1.5) U/mg prot, (3.18 +/- 0.51)%, 3.081 +/- 0.823, (0.15 +/- 0.03) pg/mg prot, (51 +/- 7) U/mg prot, P < 0.05 or < 0.01], and lung injury was attenuated. CONCLUSION: CO inhalation protects lung from injury by regulating oxidative/anti-oxidative and inflammatory/anti-inflammatory disorders, inhibiting excessive cell apoptosis and up-regulating HO-1 expression, which may play an important role in the pathogenesis of LPS-induced ALI.

Acute Lung Injury↗
PubMed2006

[Preliminary study on a new sentinel lymphoscintigraphy agent 99mTc-Rituximab for breast patient].

OBJECTIVE: To develop a new imaging agent, (99m)Tc-Rituximab, for sentinel lymphoscinti-graphy and investigate its feasibility in detecting the sentinel lymph node (SLN) for breast cancer patient. METHODS: (99m)Tc-Rituximab was prepared by introducing (99m)Tc directly into the mclecule of Rituximab, thus a new kind of lymphoscintigraphy agent ((99m)Tc-Rituximab) was produced. Five Bal b/c mice and ten breast cancer patients underwent dynamic SLN mapping procedures using (99m)Tc-Rituximab. Axillary lymph node status in breast cancer patients were evaluated with the fusion images, which was processed by computer software. With ROI technique, SLN/background ratio and the rate of SLN uptake were calculated and the dynamic curve of SLN uptake was drawn. The other 61 breast carcinoma patients underwent routine lymphatic mapping. Sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND) were both performed in all 71 patients. Fresh SLNs and all axillary nodes were sent for pathological examination using hematoxylin and eosin (H&E) staining. RESULTS: (99m)Tc-Rituximab, with a yield of about 95.0%, can show SLN status in both mice and patients. The fusion image showed SLNs clearly, even the depth of SLNs in the axilla. The results of dynamic SLN mapping showed visible SLN starting from 10 min, up to 16 h after injecting tracer, however, secondary lymph nodes were not detectable at all. In mice, the ratio of SLN/background was 2.1, the rate of uptake was about 3.0% to 3.5%, and the equation of the curve was produced as: y = 0.036x + 2.7875, r(2) = 0.9787. For breast cancer patients, the uptake rate was different from case to case, but the cure seemed to be consistent with logarithm. The result of SLNB and ALND showed that the sensitivity and accuracy of SLNB was both 100.0%. The average number of SLNs found in each case was 2.6. Of nineteen breast cancer patients (26.8%) with lymph node metastasis, 11 were found to only have SLN metastasis. CONCLUSION: (99m)Tc-Rituximab, as a new tracer to mapping sentinel lymph node for breast cancer patient, is able to show the status of sentinel lymph node reliably. The fusing image is easy to obtain and be interpreted by the clinician.

Adult↗