PubMed Health⌕ Search

Biomedical subjects

Jie Fan

Publications and source records attributed to Jie Fan.

At least 19 recordsLinked to original sources
PubMed2006

[Construction, expression and identification of recombinant bacillus Calmette-Guérin vaccine secreting human interferon alpha-2a].

OBJECTIVE: To construct a recombinant bacillus Calmette-Guérin vaccine (BCG) secreting human interferon alpha-2a (IFNalpha-2a). METHODS: BCG Ag85B signal sequence was amplified from the genome of BCG by using polymerase chain reaction (PCR) and cloned in E.coli-BCG shuttle-vector pMV261 to get pMS. The cDNA fragment encoding human IFNalpha-2a was amplified from the plasmid pBIFNalpha-2a by using PCR and inserted into the shuttle expression vector pMV261. The recombinant plamid pMSIFNalpha-2a was identified by restriction endonuclease digestion, PCR amplification and nucleotide sequencing. pMSIFNalpha-2a was electroporated into BCG to get rBCG. The DNA and protein expressions of IFNalpha-2a gene in rBCG were determined by PCR and Western blotting respectively. IFNalpha-2a in the culture supernatant of rBCG was detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: The recombinant plamid pMSIFNalpha-2a was constructed successfully and confirmed by restriction endonuclease analysis, PCR detection and nucleotide sequencing analysis. pMSIFNalpha-2a was successfully transformed into BCG by electroporation and were capable of synthesizing and secreting cytokine IFNalpha-2a. Western blotting revealed that the secretive proteins could specially combine with antibody against human IFNalpha-2a. the level of IFNalpha-2a (324.57 pg/ml) in the culture supernatant of rBCG was higher than control group by ELISA assay. CONCLUSION: The constructed recombinant BCG strain produces and secretes human IFNalpha-2a and it will be used in the treatment of superficial bladder cancer.

BCG Vaccine↗
PubMed2006

Nanopore-based proteolytic reactor for sensitive and comprehensive proteomic analyses.

Various silica-based microreactors have been designed that use enzyme immobilization to address technical concerns in proteolysis including inefficient and incomplete protein digestion. Most of current designs for proteolytic reactors can improve either protease stability or proteolysis efficiency of individual protein(s). However, the desired features such as rapid digestion, larger sequence coverage, and high sensitivity have not been achieved by a single microreactor design for broad range proteins with diverse physical properties. Here, unlike conventional enzyme immobilization strategies, we describe a novel proteolytic nanoreactor based on the unique three-dimensional nanopore structure of our newly synthesized mesoporous silica (MPS), FDU-12, which integrates substrate enrichment, "reagent-free" protein denaturation, and efficient proteolytic digestion. In our design, protein substrates were first captured by MPS nanopore structure and were concentrated from the solution. Following the pH change and applying trypsin, the denaturation and concurrent proteolysis of broad-range proteins were efficiently achieved. In minutes, many more sample peptides from the in-nanopore digestion of protein mixtures were detected by mass spectrometry, resulting in the identifications of a broad range of diverse proteins with high sequence coverage. The unique features of FDU-12 nanostructure that allow rapid, complete proteolysis and resulting enhanced sequence coverage of individual proteins were investigated by using Raman spectroscopy and comparative studies with respect to other MPSs.

Animals↗
PubMed2006

Adsorption of aqueous alkylphenol ethoxylate surfactants by mesoporous carbon CMK-3.

Mesoporous carbon, CMK-3, was prepared using hexagonal SBA-15 mesoporous silica as the template and the adsorption of nonylphenol ethoxylates (NPE) onto CMK-3 was investigated. The adsorption process was well described using pseudo-second-order kinetics. At initial NPE concentrations of 107 and 530 mg l(-1), the adsorption rate constants were found to be 5.6 x 10(-3) and 8.7 x 10(-4) g mg(-1) min(-1), indicating that a higher initial concentration or adsorption amount resulted in a lower adsorption rate. NPE adsorption onto CMK-3 fitted a Langmuir-Freundlich model and the maximum amounts of NPE absorbed at 15, 25, and 35 degrees C were 923, 720, and 463 mg g(-1), suggesting an elevated adsorption capacity of CMK-3 for NPE with decreased adsorption temperature. In addition, increasing adsorption temperature led to the change of the adsorption model from the Langmuir-Freundlich to the Langmuir model. N2 adsorption results showed that the adsorption of NPE led to a decrease in the mesopore volume of CMK-3. However, the pore width of NPE-loaded CMK-3 was found to be identical to that of CMK-3.

Adsorption↗
PubMed2006

Comment on "Factors influencing the removal of fluoride from aqueous solution by calcined Mg-Al-CO3 layered double hydroxides".

Lv et al. [L. Lv, J. He, M. Wei, D.G. Evans, X. Duan, Factors influencing the removal of fluoride from aqueous solution by calcined Mg-Al-CO3 layered double hydroxides, J. Hazard. Mater. B 133 (2006) 119-128] previously investigated the fluoride removal using calcined Mg-Al-CO3 layered double hydroxides (CLDH) as the sorbents. The present comment further discusses the mechanism of fluoride adsorption onto CLDH.

Adsorption↗
PubMed2006

One-step one-phase synthesis of monodisperse noble-metallic nanoparticles and their colloidal crystals.

A variety of metallic nanoparticles with a narrow size distribution have been synthesized in a facile one-phase method in which amine-borane complexes are applied as reducing agents. It is particularly striking that large colloidal crystals with sizes up to tens of micrometers can directly form from the reaction mixtures without any further treatment. By using the synthetic route described, large-scale syntheses of both mono- and alloyed metallic nanoparticles with a narrow size distribution can be easily achieved.

Journal Article↗
PubMed2006

Influence of wastewater composition on nitrogen and phosphorus removal and process control in A2O process.

A bench-scale anaerobic-anoxic-oxic (A2O) bioreactor with steady denitrifying phosphorus removal performance was tested to determine the influence of influent C/N ratio (SCOD/TN) and C/P ratio (SCOD/TP) on biological nutrient removal for treating synthetic brewage wastewater; meanwhile, the spatial profiles of DO, pH and ORP sensors in such systems were investigated. The results showed that influent C/N ratio had significant effect on the TN, TP removal efficiencies and the ratio of anoxic to aerobic P uptake amount. The maximal TN and TP removal efficiencies could be achieved when influent C/N ratio was kept at about 7.1 and 5, respectively. Besides, the ratio of anoxic to aerobic P uptake amount was found to be linearly dependent on the influent C/N ratio with coefficient R2 of 0.685 when total recirculation ratio was constant at 3.5. Influent C/P ratio had an important effect on the TP removal efficiency, while it hardly affected TN removal efficiency. In addition, the TP removal efficiency reached the maximum for influent C/P ratio of 42. On the other hand, it was also found that the typical profiles of DO, pH and ORP sensors could be observed, and they have similar trends at the different influent C/N ratio and C/P ratio. It was suggested that the operational state could be well known according to the changes of simple on-line sensors.

Bacteria, Anaerobic↗
PubMed2005

Hemorrhagic shock-activated neutrophils augment TLR4 signaling-induced TLR2 upregulation in alveolar macrophages: role in hemorrhage-primed lung inflammation.

Hemorrhagic shock renders patients susceptible to the development of acute lung injury in response to a second inflammatory stimulus by as yet unclear mechanisms. We investigated the role of neutrophils (PMN) in alveolar macrophage (AMphi) priming, specifically, the role in mediating Toll-like receptor (TLR)4 and TLR2 cross talk in AMphi. Using a mouse model of hemorrhagic shock followed by intratracheal administration of LPS, we explored a novel function of shock-activated PMN in the mechanism of TLR2 upregulation induced by LPS-TLR4 signaling in AMphi. We showed that antecedent hemorrhagic shock enhanced LPS-induced TLR2 upregulation in AMphi. In neutropenic mice subjected to shock, the LPS-induced TLR2 expression was significantly reduced, and the response was restored upon repletion with PMN obtained from shock-resuscitated mice but not by PMN from sham-operated mice. These findings were recapitulated in mouse AMphi cocultured with PMN. The enhanced TLR2 upregulation in AMphi augmented the expression of macrophage inflammatory protein-2, TNF-alpha, and macrophage migration inhibitory factor in the AMphi in response to sequential challenges of LPS and peptidoglycan, a prototypical TLR2 ligand, which physiologically associated with amplified AMphi-induced PMN migration into air pouch and lung alveoli. Thus TLR2 expression in AMphi, signaled by TLR4 and regulated by shock-activated PMN, is an important positive-feedback mechanism responsible for shock-primed PMN infiltration into the lung after primary PMN sequestration.

Animals↗
PubMed2005

Mesoporous silica nanoreactors for highly efficient proteolysis.

Protein digestion inside the nanoreactor channels of mesoporous silica (SBA-15) is reported, and evaluated by using peptide-mass mapping. Both proteases and substrates were efficiently captured within these biocompatible nanoreactors. After 10 minutes, the mass spectrum of the protein digests released from the mesoporous-silica-based nanoreactors revealed the presence of eight peptides covering 58% of the protein sequence with an intense signal (signal/noise ratio > 70). In comparison, the conventional overnight in-solution digestion of proteins under otherwise identical conditions generated only three peptides (27% sequence coverage). We propose that this order-of-magnitude increase in the proteolytic reaction rate is mainly attributed to two factors: substrate enrichment within mesoporous silica channels and enzyme immobilization. The surface properties and macrostructure of the mesoporous silica were studied to reveal their significant influence on proteolytic reactions.

Hydrolysis↗
PubMed2005

Opsin activation of transduction in the rods of dark-reared Rpe65 knockout mice.

Rpe65 knockout mice (Rpe65-/-) are unable to synthesize the visual pigment chromophore 11-cis retinal; however, if these animals are reared in complete darkness, the rod photoreceptors accumulate a small amount of 9-cis retinal and its corresponding visual pigment isorhodopsin. Suction-electrode recording of single rods from dark-reared Rpe65-/- mice showed that the rods were about 400 times less sensitive than wild-type control rods and that the maximum responses were much smaller in amplitude. Spectral sensitivity measurements indicated that Rpe65-/- rod responses were generated by isorhodopsin rather than rhodopsin. Sensitivity and pigment concentration were compared in the same mice by measuring light responses from rods of one eye and pigment concentration from the retina of the other eye. Retinas had 11-35% of the normal pigment level, but the rods were of the order of 20-30 times less sensitive than could be accounted for by the loss in quantum catch. This extra desensitization must be caused by opsin-dependent activation of the visual cascade, which leads to a state equivalent to light adaptation in the dark-adapted rod. By comparing the sensitivity of dark-reared Rpe65-/- rods to that produced in normal rods by background light, we estimate that Rpe65-/- opsin is of the order of 2.5x10(-5) as efficient in activating transduction as photoactivated rhodopsin (Rh*) in WT mice. Dark-reared Rpe65-/- rods are less desensitized than rods from cyclic light-reared Rpe65-/- mice, have about 50% more photocurrent and degenerate at a slower rate. Retinas sectioned after 9 months in darkness show a larger number of photoreceptor nuclei in dark-reared animals than in cyclic light-reared animals, though both have fewer nuclei than in cyclic light-reared wild-type retinas. Both also have shorter outer segments and a lower free-Ca2+ concentration. These experiments provide the first quantitative measurement of opsin activation in physiologically responding mammalian rods.

Animals↗
PubMed2005

The BRCA2 homologue Brh2 nucleates RAD51 filament formation at a dsDNA-ssDNA junction.

The BRCA2 tumour suppressor is essential for the error-free repair of double-strand breaks (DSBs) in DNA by homologous recombination. This is mediated by RAD51, which forms a nucleoprotein filament with the 3' overhanging single-stranded DNA (ssDNA) of the resected DSB, searches for a homologous donor sequence, and catalyses strand exchange with the donor DNA. The 3,418-amino-acid BRCA2 contains eight approximately 30-amino-acid BRC repeats that bind RAD51 (refs 5, 6) and a approximately 700-amino-acid DBD domain that binds ssDNA. The isolated BRC and DBD domains have the opposing effects of inhibiting and stimulating recombination, respectively, and the role of BRCA2 in repair has been unclear. Here we show that a full-length BRCA2 homologue (Brh2) stimulates Rad51-mediated recombination at substoichiometric concentrations relative to Rad51. Brh2 recruits Rad51 to DNA and facilitates the nucleation of the filament, which is then elongated by the pool of free Rad51. Brh2 acts preferentially at a junction between double-stranded DNA (dsDNA) and ssDNA, with strict specificity for the 3' overhang polarity of a resected DSB. These results establish a BRCA2 function in RAD51-mediated DSB repair and explain the loss of this repair capacity in BRCA2-associated cancers.

Adenosine Triphosphatases↗
PubMed2005

Vascular endothelial growth factor expression in the retinal pigment epithelium is essential for choriocapillaris development and visual function.

The choroid in the eye provides vascular support for the retinal pigment epithelium (RPE) and the photoreceptors. Vascular endothelial growth factor (VEGF) derived from the RPE has been implicated in the physiological regulation of the choroidal vasculature, and overexpression of VEGF in this epithelium has been considered an important factor in the pathogenesis of choroidal neovascularization in age-related macular degeneration. Here, we demonstrate that RPE-derived VEGF is essential for choriocapillaris development. Conditional inactivation of VEGF expression in the RPE (in VEGFrpe-/- mice) results in the absence of choriocapillaris, occurrence of microphthalmia, and the loss of visual function. Severe abnormalities of RPE cells are already observed when VEGF expression in the RPE is only reduced (in VEGFrpe+/- mice), despite the formation of choroidal vessels at these VEGF levels. Finally, using Hif1arpe-/- mice we demonstrate that these roles of VEGF are not dependent on hypoxia-inducible factor-1alpha-mediated transcriptional regulation of VEGF expression in the RPE. Thus, hypoxia-inducible factor-1alpha-independent expression of VEGF is essential for choroid development.

Animals↗
PubMed2004

Association between clinical characteristics and expression abundance of RTKN gene in human bladder carcinoma tissues from Chinese patients.

PURPOSE: Bladder carcinoma is the most common urological malignancy in China. Gene mutation may be one of causes of carcinogenesis in the cancer. We therefore investigated the mRNA expression of RTKN gene in clinic malignant bladder carcinoma and explored the relationship between the novel gene and the cancer. METHODS: Total RNA was extracted from 33 surgically resected specimens of bladder carcinoma and 19 specimens of tumor-free bladder tissues. After the optimal reverse-transcription polymerase chain reaction condition was established, the mRNA expression levels of the RTKN gene in the lesions and tumor-free bladder tissues were examined semiquantitatively, and the relationships between expression levels of RTKN and clinical pathological features were analyzed. RESULTS: The expression of RTKN gene mRNA in 33 human bladder carcinoma tissues was significantly higher than that in 19 human tumor-free bladder tissues (0.937+/-0.103 vs. 0.350+/-0.082). The average ratio of RTKN expression in neoplasms to that in tumor-free bladder tissues was 0.350+/-0.164. Based on this ratio the 33 patients were divided into three groups: a down-regulated expression group (n=2), an up-regulated expression group (n=22), and an unchanged group (n=9). Although the chi(2) test demonstrated a statistically nonsignificant differences in RTKN expression between tumor stages Ta, T(1), and T(2) overall in the 33 human bladder carcinoma, the t test showed that there were statistically significant differences between solitary and multiple tumors, between the paired group aged younger or older than 70 years in 27 de novo bladder carcinoma patients, and between the groups with tumor larger or smaller than 2.25 cm(3). CONCLUSIONS: These results suggest that the RTKN gene is involved in bladder carcinogenesis and progression in bladder carcinoma, indicating that RTKN gene could be a molecular target in cancer therapy.

Adenocarcinoma↗
PubMed2004

LPS activation of Toll-like receptor 4 signals CD11b/CD18 expression in neutrophils.

We identify herein a novel signaling function of the Toll-like receptor-4 (TLR4), the lipopolysaccharide (LPS) receptor mediating the innate immune response, in inducing the expression of CD11b/CD18 integrin in polymorphonuclear leukocytes (PMNs). Studies were made in PMNs isolated from TLR4-deficient (TLR4(-/-)) and C57BL/6 [wild-type (WT)] mice. We observed increased CD11b expression in WT PMNs within 3 h after LPS challenge, whereas CD11b was not expressed in TLR4(-/-) PMNs above basal levels. TLR4-activated CD11b expression was cycloheximide sensitive and involved the activation of transcription factors, NF-kappaB and c-Jun/PU.1. TLR4(-/-) PMNs challenged with LPS were functionally defective as the result of the impaired CD11b expression in that they failed to adhere and did not migrate across endothelial cells in response to N-formylmethionyl-leucyl-phenylalanine. TLR4 also promoted increased binding of LPS to PMNs on the basis of expression of CD11b. Thus TLR4 signaling activates synthesis and upregulation of CD11b and is essential for PMN adhesion and transmigration. Our data suggest an important role of TLR4-activated CD11b expression in the mechanism of the PMN host-defense response to LPS.

Animals↗
PubMed2004

Hypertonic preconditioning prevents hepatocellular injury following ischemia/reperfusion in mice: a role for interleukin 10.

Ischemia/reperfusion (I/R) of the liver occurs in many clinical scenarios including trauma, elective surgery, and transplantation. Events initiated by this process can lead to inflammation in the liver, culminating in local injury as well as distant organ dysfunction. Recent studies have suggested that hypertonic saline exerts anti-inflammatory effects, which may be beneficial in preventing organ injury. In the present study, we examine the effect of hypertonic saline on the development of liver inflammation following I/R in both rat and mouse models. Hypertonic pretreatment was shown to prevent liver enzyme release concomitant with a reduction in liver neutrophil sequestration. Hypertonic saline appeared to exert this effect by inhibiting liver tumor necrosis factor alpha (TNF-alpha) generation, an effect that culminated in reduced liver adhesion molecule expression. Hypertonic saline pretreatment was shown to augment liver interleukin 10 (IL-10) expression following I/R, as a potential mechanism underlying its anti-inflammatory effect. To examine the role of IL-10 in the protective effect of hypertonic saline on liver I/R injury, we used a murine model of I/R. In wild type mice, hypertonic pretreatment similarly prevented liver injury induced by I/R. However, in IL-10 knockout animals, hypertonic pretreatment was unable to prevent the liver enzyme release, TNF-alpha generation, or neutrophil sequestration induced by I/R. In conclusion, these findings define a novel mechanism responsible for the anti-inflammatory effects of hypertonic saline and also suggest a potential clinical role for hyperosmolar solutions in the prevention of liver injury associated with I/R.

Animals↗
PubMed2004

Impaired induction of IL-10 expression in the lung following hemorrhagic shock.

The balance between pro- and anti-inflammatory cytokines is considered to be an important determinant of the magnitude of inflammation in a number of disease states. We previously showed that resuscitated hemorrhagic shock augmented LPS-induced release of proinflammatory molecules by alveolar macrophages (AM). In the present studies, we evaluated the expression and regulation of the counter inflammatory cytokine IL-10 in the lung using this model. We hypothesized that impaired up-regulation of IL-10 in shock/resuscitated animals might serve as a mechanism contributing to accentuated lung inflammation. In a rodent model, animals exposed to LPS alone exhibited enhanced IL-10 mRNA levels in lung tissue as well as in AM, but antecedent shock/resuscitation delayed and attenuated the LPS-induced IL-10 mRNA levels. The ability of shock to attenuate LPS-stimulated IL-10 was also seen in the protein levels. This effect correlated with an augmented expression of cytokine-induced neutrophil chemoattractant (CINC) mRNA. Shock/resuscitated animals given exogenous IL-10 had reduced proinflammatory response, as shown by decreased expression of CINC mRNA and decreased neutrophil sequestration in the lung. Shock/resuscitation plus LPS markedly reduced the transcription rate of IL-10 mRNA compared to LPS alone but did not affect IL-10 mRNA stability. Reduced IL-10 transcription was not caused solely by impaired nuclear translocation of STAT3 and Sp1/Sp3 transcription factors because LPS-induced nuclear translocation of these factors was augmented by antecedent shock. Considered together, these findings show that shock/resuscitation suppresses LPS-induced IL-10 expression by AM in the lung by inhibiting IL-10 gene transcription. Failed up-regulation of counter inflammatory cytokines may contribute to augmented organ dysfunction in trauma patients.

Animals↗
PubMed2003

Isorhodopsin rather than rhodopsin mediates rod function in RPE65 knock-out mice.

The chromophore of visual pigments is 11-cis-retinal and, thus, in its absence, opsin is not photosensitive and no visual function exists. However, in the RPE65 knockout (Rpe65-/-) mouse, where synthesis of 11-cis-retinal does not occur, a minimal visual response from rod photoreceptors is obtained. We have examined if an alternative pathway exists for cis-retinoid generation in the absence of RPE65. Cyclic-light-reared, 2-month-old Rpe65-/- mice were placed in complete darkness. No exogenous retinoids were administered. After 4 weeks, enhanced a- and b-wave amplitudes were obtained, increasing >10-fold for the a-wave and >3-fold for the b-wave as compared with cyclic-light-reared Rpe65-/- mice. Visual-pigment levels increased to approximately 10 pmol per retina, compared with no measurable pigment for cyclic-light-reared Rpe65-/- mice. The lambdamax of the isolated pigment was 487 nm, characteristic for isorhodopsin. Retinoid extractions confirmed the presence of 9-cis-retinal and the absence of 11-cis-retinal. Once the Rpe65-/- mice were returned to cyclic light, within 48 h the electroretinogram function returned to levels found in Rpe65-/- mice maintained in cyclic light. This dark-mediated pathway is also operational in older animals, because 13-month-old Rpe65-/- mice kept in prolonged darkness (12 weeks) had increased isorhodopsin levels and electroretinogram a- and b-wave amplitudes. These studies demonstrate that a pathway exists in the eye for the generation of 9-cis-retinal that is independent of RPE65 and light.

Animals↗