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Biomedical subjects

Jie Xu

Publications and source records attributed to Jie Xu.

At least 55 records · Page 3Linked to original sources
PubMed2005

Characterization of spectroscopic of Pr(DBM)3(TPPO)2 containing poly(methyl methacrylate).

The absorption and fluorescence spectra of Pr(DBM)3(TPPO)2 (DBM: dibenzoylmethane, TPPO: triphenylphosphine oxide) containing poly(methyl methacrylate) (PMMA) were measured. The energy levels are assigned and analyzed in terms of the free-ion Hamiltonian model. From the data available in the absorption spectrum, various spectroscopic parameters such as the spherically symmetric part of the free-ion Hamiltonian (E(AVG)), Slater-Condon (F2, F4, F6), spin-orbit interaction (zeta), Judd-Ofelt (omega2, omega4, omega6) parameters and the reduced matrix elements are derived. The radiative properties of Pr(DBM)3(TPPO)2 containing PMMA were also predicted according to the Judd-Ofelt theory. The values of the fluorescence branching ratio and the emission cross section of 3P0 --> 3F2 fluorescence transition revealed that Pr(DBM)3(TPPO)2 containing PMMA is an efficient luminescent material.

Models, Chemical↗
PubMed2005

Endogenous attenuation of allergic lung inflammation by syndecan-1.

The airway plays a vital role in allergic lung diseases by responding to inhaled allergens and initiating allergic inflammation. Various proinflammatory functions of the airway epithelium have been identified, but, equally important, anti-inflammatory mechanisms must also exist. We show in this study that syndecan-1, the major heparan sulfate proteoglycan of epithelial cells, attenuates allergic lung inflammation. Our results show that syndecan-1-null mice instilled with allergens exhibit exaggerated airway hyperresponsiveness, glycoprotein hypersecretion, eosinophilia, and lung IL-4 responses. However, administration of purified syndecan-1 ectodomains, but not ectodomain core proteins devoid of heparan sulfate, significantly inhibits these inflammatory responses. Furthermore, syndecan-1 ectodomains are shed into the airway when wild-type mice are intranasally instilled with several biochemically distinct inducers of allergic lung inflammation. Our results also show that syndecan-1 ectodomains bind to the CC chemokines (CCL7, CCL11, and CCL17) implicated in allergic diseases, inhibit CC chemokine-mediated T cell migration, and suppress allergen-induced accumulation of Th2 cells in the lung through their heparan sulfate chains. Together, these findings uncover an endogenous anti-inflammatory mechanism of the airway epithelium where syndecan-1 ectodomains attenuate allergic lung inflammation via suppression of CC chemokine-mediated Th2 cell recruitment to the lung.

Adjuvants, Immunologic↗
PubMed2005

Specific humoral immune responses in rhesus monkeys vaccinated with the Alzheimer's disease-associated beta-amyloid 1-15 peptide vaccine.

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative disorder characterized by overproduction of beta-amyloid (Abeta), with the subsequent pathologic deposition of Abeta which is important for memory and cognition. Recent studies showed murine models of AD and AD patients inoculated with Abeta(1-42) peptide vaccine had a halted or delayed pathological progression of AD. Unfortunately, the clinical phase IIa trial of Abeta(1-42) peptide vaccine (AN1792) was halted prematurely because of episodes of menigoencephalitis in 18 of the vaccinated patients. The vaccination of BALB/c or Tg2576 transgenic mouse with Abeta(1-15) peptide vaccine is safe and the immune effects are satisfactory. This study further characterizes the specific humoral immune responses in adult rhesus monkeys induced by Abeta(1-15) peptide vaccine. METHODS: Five male adult rhesus monkeys were injected intramuscularly with Abeta(1-15) peptide vaccine at baseline and at weeks 2, 6, 10, 14, 18 and 22. The titers and IgG isotypes of the antibody against Abeta(1-42) in serum was measured by Enzyme-linked Immunosorbent Assay (ELISA). The specificity of the antibody against Abeta(1-42) was determined by Western blot. The Abeta plaques in Tg2576 transgenic mouse brain were stained with the antiserum using immunohistochemistry method. RESULTS: At the eighth week after the vaccination, antibody against Abeta(1-42) began to develop significantly in serum. The titers of the antibody increased following vaccine boosted and reached 1:3840 at the twenty-fourth week, then decreased after the termination of inoculation. The IgG1 was accounted for the highest level in the antiserum pool. The antibody against Abeta(1-42) showed high specificity. The Abeta plaques in Tg2576 transgenic mouse brain were labeled with the antiserum. CONCLUSION: Abeta(1-15) vaccine can induce vigorously specific humoral immune responses in adult rhesus monkey.

Amyloid beta-Peptides↗
PubMed2005

Meat and milk compositions of bovine clones.

The technology is now available for commercial cloning of farm animals for food production, but is the food safe for consumers? Here, we provide data on >100 parameters that compare the composition of meat and milk from beef and dairy cattle derived from cloning to those of genetic- and breed-matched control animals from conventional reproduction. The cloned animals and the comparators were managed under the same conditions and received the same diet. The composition of the meat and milk from the clones were largely not statistically different from those of matched comparators, and all parameters examined were within the normal industry standards or previously reported values. The data generated from our match-controlled experiments provide science-based information desired by regulatory agencies to address public concerns about the safety of meat and milk from somatic animal clones.

Animals↗
PubMed2005

Prediction of vascular tissue engineering results with artificial neural networks.

Tissue engineers are often confused on finding the most successful strategy for specific patient. In this study, we used artificial neural networks to predict the outcomes of different vascular tissue engineering strategies, thus providing advisory information for experimental designers. Over 30 variables were used as features of the tissue engineering strategies. Different architectures of artificial neural networks with back propagation algorithm were tested to obtain the best model configuration for the prediction of the tissue engineering strategies. In the computational experiments, the artificial neural networks with one and two hidden layers could, respectively, detect unsuccessful strategies with the highest predictive accuracy of 91.45 and 94.24%. In conclusion, artificial intelligence has great potential in tissue engineering decision support. It can provide accurate advisory information for tissue engineers, thus reducing failures and improving therapeutic effects.

Animals↗
PubMed2005

Sm(DBM)3Phen-doped poly(methyl methacrylate) for three-dimensional multilayered optical memory.

We report on the formation of submicrometer voids within Sm(DBM)3Phen-doped poly(methyl methacrylate) (PMMA) under multiphoton absorption excited by an infrared laser beam. An ultrashort-pulsed laser beam with a pulse width of 200 fs at a wavelength of 800 nm is focused into doped PMMA. The large changes in refractive index and the fluorescence associated with a void allow conventional optical microscopy and reflection-type confocal microscopy to be used as detection methods. Voids can be arranged in a three-dimensional multilayered structure for high-density optical data storage.

Journal Article↗
PubMed2005

SLC26A9 is expressed in gastric surface epithelial cells, mediates Cl-/HCO3- exchange, and is inhibited by NH4+.

HCO3- secretion by gastric mucous cells is essential for protection against acidic injury and peptic ulcer. Herein we report the identification of an apical HCO3- transporter in gastric surface epithelial cells. Northern hybridization and RT-PCR demonstrate the expression of this transporter, also known as SLC26A9, in mouse and rat stomach and trachea (but not kidney). In situ hybridization in mouse stomach showed abundant expression of SLC26A9 in surface epithelial cells with apical localization on immunofluorescence labeling. Functional studies in HEK-293 cells demonstrated that SLC26A9 mediates Cl-/HCO3- exchange and is also capable of Cl--independent HCO3- extrusion. Unlike other anion exchangers or transport proteins reported to date, SLC26A9 activity is inhibited by ammonium (NH4+). The inhibitory effect of NH4+ on gastric HCO3- secretion was also indicated by reduced gastric juxtamucosal pH (pHjm) in rat stomach in vivo. This report is the first to describe the inhibition of HCO3- transport in vitro and the reduction of pHjm in stomach in vivo by NH4+. Given its critical localization on the apical membrane of surface epithelial cells, its ability to transport HCO3-, and its inhibition by NH4+, we propose that SLC26A9 mediates HCO3- secretion in surface epithelial cells and is essential for protection against acidic injury in the stomach. Disease states that are associated with increased ammonia (NH3)/NH4+ generation (e.g., Helicobacter pylori) may impair gastric HCO3- secretion and therefore predispose patients to peptic ulcer by inhibiting SLC26A9.

Animals↗
PubMed2005

Hybrid artificial liver support system for treatment of severe liver failure.

AIM: To construct a novel hybrid artificial liver support system (HALSS) and to evaluate its efficacy in patients with severe liver failure. METHODS: Hepatocytes were isolated from suckling pig by the modified Seglen's method. Isolated hepatocytes were cultured in a spinner flask for 24 h to form spheroids before use and the functions of spheroids were detected. HALSS consisted of a plasma separator, a hemo-adsorba and a bioreactor with hepatocytes spheroids in its extra-fiber space. HALSS was applied to 10 patients with severe liver failure. The general condition and the biochemical indexes of the patients were studied just before and after the treatment. RESULTS: The number of cells per liver was about 2-4 x 10(10) (mean, 3.1+/-1.5 x 10(10)). The cell viabilities were more than 95%. After 24 h of spheroid culture, most hepatocytes formed spheroids. The levels of albumin and urea in the medium of spheroid culture were higher than those in supernatant of petri dish culture (P = 0.0015 and 0.0001, respectively). The capacity of albumin production and urea synthesis remained stable for more than one wk and declined rapidly after two weeks in vitro. In HALSS group, the duration of HALSS treatment was 6-10 h each time. All patients tolerated the treatment well without any fatal adverse reaction. After HALSS treatment, the general condition, psychic state, encephalopathy and hepatic function of the patients were improved. The survival rate of the HALSS group, Plasmapheresis group and control group was 30% (3/10), 20% (2/10) and 0% (0/10), respectively (P = 0.024). Two weeks after treatment, Tbil and ALT decreased and the PTA level elevated in HALSS group and pasmapheresis group (P value: 0.015 vs 0.020, 0.009 vs 0.012 and 0.032 vs 0.041, respectively). But there was no significant change of blood albumin concentration before and after treatment in HALSS group and Plasmapheresis group. CONCLUSION: The HALSS established by us is effective in supporting liver function of patients with severe liver failure.

Albumins↗
PubMed2005

Gene 33 inhibits apoptosis of breast cancer cells and increases poly(ADP-ribose) polymerase expression.

The structure of the Gene 33 protein suggests that it plays a role in intracellular signaling and Gene 33 is induced by many mitogenic and stressful stimuli. Previously, we found that Gene 33 expression is significantly induced by retinoic acid (RA), insulin and synergistically by both in a liver-derived cell line. In the present study, we investigated the basal expression and regulation of Gene 33 in multiple human breast cancer cell lines. These cell lines expressed different levels of Gene 33 protein, but Gene 33 protein was not regulated by RA or insulin, either alone, or in combination. However, epidermal growth factor (EGF) induced Gene 33 expression in SK-BR-3 cells and this induction was inhibited by co-treatment with RA. There was a strong correlation between endogenous basal Gene 33 expression and doubling time. Exogenous expression of Gene 33 in MCF-7 cells did not affect cell cycle distribution, but inhibited apoptosis and specifically increased the level of Poly(ADP-ribose) Polymerase (PARP-1) protein. This suggests that Gene 33 promotes breast cancer cell growth by an anti-apoptotic rather than a mitogenic effect, possibly involving up-regulation of PARP-1.

Adaptor Proteins, Signal Transducing↗
PubMed2005

A practical approach to the degradation of polychlorinated biphenyls in transformer oil.

A practical and efficient disposal method for hydrodechlorination of polychlorinated biphenyls (PCBs) in transformer oil is reported. Transformer oil containing PCBs was treated by nanometric sodium hydride (nano-NaH) and transition metal catalysts. High destruction and removal efficiency (89.8%) can be attained by nano-NaH alone under mild conditions. The process exhibits apparent characteristics of a first order reaction. The reductive ability of nano-NaH was enhanced by the addition of transition metal catalysts. In the presence of TiCl4, 99.9% PCBs was hydrodechlorinated. The complex reducing reagents, Ni(OAc)2+i-PrONa, show extra hydrodechlorinating activity for di-chlorinated biphenyls.

Catalysis↗
PubMed2005

Triglycidylamine crosslinking of porcine aortic valve cusps or bovine pericardium results in improved biocompatibility, biomechanics, and calcification resistance: chemical and biological mechanisms.

We investigated a novel polyepoxide crosslinker that was hypothesized to confer both material stabilization and calcification resistance when used to prepare bioprosthetic heart valves. Triglycidylamine (TGA) was synthesized via reacting epichlorhydrin and NH(3). TGA was used to crosslink porcine aortic cusps, bovine pericardium, and type I collagen. Control materials were crosslinked with glutaraldehyde (Glut). TGA-pretreated materials had shrink temperatures comparable to Glut fixation. However, TGA crosslinking conferred significantly greater collagenase resistance than Glut pretreatment, and significantly improved biomechanical compliance. Sheep aortic valve interstitial cells grown on TGA-pretreated collagen did not calcify, whereas sheep aortic valve interstitial cells grown on control substrates calcified extensively. Rat subdermal implants (porcine aortic cusps/bovine pericardium) pretreated with TGA demonstrated significantly less calcification than Glut pretreated implants. Investigations of extracellular matrix proteins associated with calcification, matrix metalloproteinases (MMPs) 2 and 9, tenascin-C, and osteopontin, revealed that MMP-9 and tenascin-C demonstrated reduced expression both in vitro and in vivo with TGA crosslinking compared to controls, whereas osteopontin and MMP-2 expression were not affected. TGA pretreatment of heterograft biomaterials results in improved stability compared to Glut, confers biomechanical properties superior to Glut crosslinking, and demonstrates significant calcification resistance.

Animals↗
PubMed2005

Prolonged insulin treatment inhibits GH signaling via STAT3 and STAT1.

Growth hormone (GH) and insulin are important regulators of cellular and whole body metabolism as well as somatic growth and body composition. Studies have indicated complex feedback effects of GH on insulin action and of insulin on GH signaling pathways. Previous studies in our laboratory have shown that GH induction of signal transducers and activators of transcription (STAT)5B tyrosine phosphorylation is inhibited by prolonged insulin treatment, probably via downregulation of GHR. Here, we find that in rat H4IIE hepatoma cells GH-induced tyrosine phosphorylation of two other STATs (STAT3 and STAT1) was also greatly reduced following prolonged insulin pretreatment compared with that induced by GH alone. In the present work, total STAT5B and STAT1 protein levels were not altered by prolonged insulin treatment. However, prolonged insulin treatment (16 h; 10 or 100 nM) resulted in a 30-40% reduction of total STAT3 protein, with little change at 0.1 and 1.0 nM insulin. Thus, there is a selective reduction of total STAT3 protein levels by insulin, but only at high concentration of insulin. Basal tyrosine phosphorylated (PY)-STAT3 was also significantly reduced by prolonged insulin treatment, and to a greater extent than total STAT3 protein levels. The inhibitory effect of insulin on total STAT3 protein and basal PY-STAT3 levels was dependent on activation of the MEK-ERK pathway, rather than the PI3K pathway. In contrast, the MEK-ERK pathway did not play a major role in insulin's inhibition of GH-induced PY-STAT3 and PY-STAT1. The present studies indicate that prolonged hyperinsulinemia, such as that found in some obese patients or patients with Type 2 diabetes mellitus, may have profound effects on GH signaling via STAT3 and STAT1.

Animals↗
PubMed2005

[Specific humoral immune response in Rhesus monkeys vaccinated immune response with Abeta42 peptide vaccine].

AIM: To observe the humoral immuneresponse in Rhesus monkey induced by Abeta42 peptide vaccination. METHODS: Five male Rhesus monkeys were received intramuscular injection of Abeta42 peptide vaccine at 0, 2nd, 6th, 10th, 14th, 18th, 22th week. The titers and Ig subclasses of the serum anti-Abeta42 antibody were measured by ELISA. The specificity of the anti-Abeta42 antibody was determined by Western blot. The recognition of Abeta plaques in Tg2576-transgenic mouse brain tissue by anti-Abeta42 serum were detected by immunohistochemical staining. RESULTS: At the 8th week after the vaccination, the serum anti-Abeta42 antibody was detected. The titers of the antibody increased with times of booster inoculation and reached 1:4,320 at the 24th week, then decreased. The produced antibodies were mainly IgG1 and IgG2(IgG2/IgG1>1). The anti-Abeta42 antibody had high specificity. The Abeta plaques in Tg2576-transgenic mouse brain tissue were recognized by the antisera. CONCLUSION: Abeta42 peptide vaccine can induce effectively specific humoral immuneresponse in Rhesus monkey.

Alzheimer Disease↗
PubMed2005

Applying informatics in tissue engineering.

OBJECTIVE: To facilitate tissue engineering strategies determination with informatics tools. METHODS: Firstly, tissue engineering experimental data were standardized and integrated into a centralized database; secondly, we used data mining tools (e.g. artificial neural networks and decision trees) to predict the outcomes of tissue engineering strategies; thirdly, a strategy design algorithm was developed, and its efficacy was validated with animal experiments; lastly, we constructed an online database and a decision support system for tissue engineering. RESULTS: The artificial neural networks and the decision trees respectively predicted the outcomes of tissue engineering strategies with the predictive accuracy of 95.14% and 85.26%. Following the strategies generated by computer, we cured 18 of the 20 experimental animals with a significantly lower cost than usual. CONCLUSION: Informatics is beneficial for realizing safe, effective and economical tissue engineering.

Artificial Intelligence↗
PubMed2005

[Selective depletion of donor alloreactive T cells by using immuno-magnetic cell sorting].

This study was aimed to explore a new method of alleviating graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation through selective elimination of human alloreactive T cells expressing either CD25(+) or CD69(+) by immuno-magnetic cell sorting (MACS). Healthy donor peripheral blood mononuclear cells were cocultivated with bone marrow mononuclear cells from HLA-nonidentical leukemia recipient with remission in one-way mixed lymphocyte culture (OWMLC). After 3 days, both CD25(+) and CD69(+) lymphocytes were removed by MACS. The depleted donor fraction and untreated donor cells were then rechallenged in a secondary mixed lymphocyte culture (MLC) with the original stimulator cells or a third party to assess relative alloreactivity. The results showed that 50% inhibition of the secondary MLC was observed in the depleted donor fraction. Alloreactivity against unrelated third-party cells was largely preserved. It is concluded that this method reduces alloreactivity while retaining reactivity against a third party target in vitro.

Antigens, CD↗
PubMed2005

[Effects of antithrombin-III on cytokines in rats with multiple organ dysfunction syndrome].

OBJECTIVE: To observe the effect of the antithrombin-III (AT-III) on cytokine levels in multiple organ dysfunction syndrome (MODS) in rats. METHODS: Seventy Wistar rats were randomly divided into three groups: normal control group, MODS group, and AT-III treatment group. The rats in MODS group and the treatment group were given lipopolysaccharide (LPS) two times to replicate systemic inflammatory response syndrome (SIRS)/MODS model. One hour after the injections of LPS, the rats in the treatment group were given AT-III (25 U/kg, 0.5 ml/100 g) intravenously. Four hours after treatment, blood samples were collected in rats. The tissue samples were collected and preserved in formalin. By use of radioimmunoassay and histopathology, the effect of the AT-III was observed in rats with SIRS/MODS. RESULTS: Endotoxin (ET), interleukin-1 (IL-1), IL-6 and tumor necrosis factor-alpha (TNF-alpha) levels were all increased significantly in MODS animals (all P<0.01), and they were decreased after AT-III treatment (all P<0.01), though still higher than those of the normal controls (all P<0.01). The pathologic changes in lung, kidney and liver in the treatment group were milder than in the MODS group. CONCLUSION: These data suggest that AT-III could inhibit systemic inflammatory response and it might be used in the treatment of SIRS/MODS.

Animals↗