Biomedical subjects

Hui Zhang

Publications and source records attributed to Hui Zhang.

At least 73 records · Page 4Linked to original sources

PubMed2006

The prognostic significance of preoperative plasma levels of osteopontin in patients with hepatocellular carcinoma.

We aimed to evaluate the prognostic value of preoperative plasma osteopontin (OPN) levels in 101 patients with hepatocellular carcinoma (HCC) who underwent liver resection. Plasma OPN levels were detected by ELISA. The association of plasma OPN levels of patients with clinicopathological characteristics, tumor recurrence, and survival was analyzed. The median plasma OPN level of patients was 176.90 ng/ml (range 13.73-780.00 ng/ml), which was significantly higher than that of 24 healthy volunteers (63.74 ng/ml, range 12.20-122.32 ng/ml). Plasma OPN levels were significantly different in patients with different numbers of tumor nodules (168.18 and 217.11 ng/ml for single and multiple nodules, respectively; P = 0.002), different Edmondson's grades (201.24, 168.36, and 503.58 ng/ml for grades I, II, and III/IV, respectively; P = 0.015), and different TNM stages (168.16, 167.54, and 216.18 ng/ml for stages I, II, and III/IV, respectively; P = 0.016). Significantly higher plasma OPN levels were found in patients with a recurrence of HCC after resection, compared with those without recurrence (213.55 versus 153.70 ng/ml; P = 0.0013). A higher plasma OPN level was a leading independent prognostic factor for both overall survival (OS) and disease-free survival (DFS) in univariate and multivariate Cox models. This suggests that the preoperative plasma OPN level can be used as a predictive marker for HCC recurrence and may be helpful to assess the prognosis of patients with HCC after surgery.

Adult↗

PubMed2006

General solution route for nanoplates of hexagonal oxide or hydroxide.

A citric acid (CA)-assisted hydrothermal process was used to prepare Fe2O3 hexagonal nanoplates with a lateral size of about 100 nm. In addition, the hexagonal nanoplates of Co(OH)2, MnCO3, and Ni(OH)2 were also synthesized by this route, indicative of the universality of the solution route presented herein. The morphologies and structures of the synthesized platelike nanostructures have been characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD). Furthermore, the mechanism for the formation of the platelike nanostructures has been preliminarily discussed. It is believed that the capping molecule of CA, which inhibits crystal growth along the <001> direction due to its chelating effect, plays a critical role in the hydrothermal formation of the nanoplates.

Journal Article↗

PubMed2006

[The characterization of regulatory T cells in peripheral blood of HBV-infected patients].

OBJECTIVE: CD4(+)CD25(high) regulatory T cells (Treg) have been shown to play an important role in maintaining peripheral tolerance against self and foreign antigens, and in suppressing T cell immune response. Our aim was to characterize circulating Treg in HBV-infected patients. METHODS: Treg in peripheral blood from 72 chronic hepatitis B (CHB) patients, 16 acute hepatitis B (AHB) patients and 32 healthy subjects were quantitatively analyzed using flow cytometry. Serum HBV markers were evaluated for each subject. HBV-DNA levels were measured using real-time RT-PCR. RESULTS: CHB patients presented a higher fraction of circulating Treg (3.9% +/- 1.4%) than those in AHB patients (3.1% +/- 0.9%) (P < 0.05), but were similar to healthy controls (3.5% +/- 0.7%). CHB patients with greater than 10(7) copies/ml of serum HBV DNA loads had a higher frequency (4.5% +/- 1.9%) of circulating Treg than health controls (P < 0.01) and the patients with less than 10(7) copies/ml of serum viral loads (3.4% +/- 0.7%). A correlation was found between circulating Treg and HBV DNA level (r = 0.32, P < 0.01). Furthermore, Treg was more frequent in convalescent phase (6.0% +/- 1.7%) than in early acute phase (3.0% +/- 0.6%). CONCLUSION: Increased peripheral Treg is found to be associated with HBV replication in chronic hepatitis B. In acute HBV infection, Treg is less frequent in early phase. The related mechanisms is under further investigation.

Acute Disease↗

PubMed2006

A dynamical model of subharmonic generation in ultrasonic infrared thermography.

Subharmonics are often observed in ultrasonic infrared thermography (UIR) system as samples are excited by ultrasonic transducers, and it is testified that, as the subharmonics appear, the detectability of cracks or defects in the sample is greatly enhanced in the UIR system. A dynamical model to explore the generation mechanism of the subharmonics and simulate the sample motion excited by an ultrasonic transducer in the UIR system is presented in this paper. In the model, the sample is continuously impacted by the transducer as the transducer is pushed to the sample by a constant force, in which the sample is simplified as a damped oscillator and the transducer is simplified as an active oscillator with constant frequency and amplitude. The impact process is also taken into account, in which the acting force is assumed to vary linearly during the impact process. A stable waveform of subharmonics in the sample can be obtained in appropriate conditions.

Algorithms↗

PubMed2006

The lumbar spinal cord glial cells actively modulate subcutaneous formalin induced hyperalgesia in the rat.

We investigated the response and relationship of glial cells and neurons in lumbar spinal cord to hyperalgesia induced by the unilateral subcutaneous formalin injection into the hindpaw of rats. It was demonstrated that Fos/NeuN immunoreactive (-IR) neurons, glial fibrillary acidic protein (GFAP)-IR astrocytes and OX42-IR microglia were distributed in dorsal horn of lumbar spinal cord, predominantly in the superficial layer. In the time-course studies, GFAP-IR astrocytes were firstly detected, OX42-IR microglia were sequentially observed, Fos/NeuN-IR neurons were found slightly late. Immunoelectron microscopy studies established that many heterotypic gap junctions (HGJs), which consisting of Cx43-IR astrocytic process on one side and Cx32-IR dendrite on the other side, were present in superficial layer of dorsal horn. Ninety-one HGJs were found in 100 areas of experimental rats and occupied 91%, while only 39% HGJs were found in control rats. In experimental rats pretreated with intrathecal (i.t.) application of the carbenoxolone (a gap junction blocker) or fluorocitrate (a glial metabolic inhibitor), the paw withdrawal thermal latency was prolonged than those application of the sterile saline (i.t.). It suggests that spinal cord glial cells may play an important role for modulation of hyperalgesia induced by noxious stimuli through HGJs which located between astrocytes and neurons.

Afferent Pathways↗

PubMed2006

Performance optimization of plate-mode sensors with bi-layered structure.

The acoustic characteristics of plate-mode sensors with bi-layered structures composed of a piezoelectric film and a non-piezoelectric substrate are studied by numerical calculations using the transfer matrix method. Performances of the sensors can be evaluated based on the theoretical calculations of the dispersion curves, electromechanical coupling coefficients and sensitivities of the plate-mode sensors with a bi-layered structure. In order to obtain the optimized operating conditions of the sensors, the operating mode, frequency and the ratios of thickness of piezoelectric film to that of the substrate are evaluated when the sensors are applied in gas and/or liquid conditions.

Computer Simulation↗

PubMed2006

Ultrasonic micro-motor using miniature piezoelectric tube with diameter of 1.0 mm.

At the present moment, the smallest piezoelectric ultrasonic micro-motors utilizing miniature PZT piezoelectric ceramic tubes were developed. The motor consists of a PZT-metal composite tube stator, two steel rotors and a thin shaft that keeps the two rotors pressing on both ends of the stator elastically. The dimensions of the PZT tube are 1.0 mm in outer diameter, 0.6 mm in inner diameter and 5.0 mm in length. The diameter and total length of the assembled micro-motor is 1.0 mm and 8 mm (including an adjusting spring), respectively. The tube-type micro-motor is driven by two pairs of alternative voltages with phase shift 90 degrees between the adjacent electrodes and operated in the first circular-bending vibration mode of the stator with the resonance frequency about 58 kHz. The experimental results show that the tube-type micro-motors have perfect performances: (i) high rotation frequency over 3000 rpm and (ii) large starting torque over 7.8 microN m under the conditions of the input voltage of 110 V(p-p) and the resonance frequency. The micro-motor is well suitable for operating in micro-spaces, such as in intravascular, micro-robots and micro-craft applications.

Journal Article↗

PubMed2006

Electrode effects on general modes in high-overtone bulk acoustic resonators.

Generally, in theoretical calculations of high-overtone bulk acoustic resonators (HBAR), metal electrode effects were always ignored. However, the acoustical impedance, thickness and loss of the electrodes affect practically the performances of HBAR operating at high-frequency. For very high-frequency cases, the thickness of the metal electrode is always on the same order of that of the piezo-film and the electrode effects on modes cannot be negligible. In this paper, based on the resonance frequency spectra and Butterworth Van Dyke equivalent circuit of HBAR, the effects of the material, loss, and thickness of the electrodes on the figure of merit, effective electromechanical coupling factor, quality factor, etc. are analyzed. It is demonstrated that the performance of HBAR can also be optimized by using the electrodes with proper impedance, loss and thickness.

Journal Article↗

PubMed2006

HSP70 vaccine in combination with gene therapy with plasmid DNA encoding sPD-1 overcomes immune resistance and suppresses the progression of pulmonary metastatic melanoma.

Many tumor immunotherapy efforts are focused on the generation of strong T-cell response against tumor antigens. However, strong T-cell response does not always coincide with tumor rejection, for which upregulated expression of immunoinhibitory molecules may be responsible. In this study, the treatment with heat shock protein 70 (HSP70) vaccine induced an infiltration of T cells into the tumor site as well as the expression of IFN-gamma and IL-2, and delayed lung metastases of tumor, but the tumor progression nonetheless occur finally. We demonstrated that B7-H1 expressed by residual tumor cells was responsible for the resistance of tumor to the therapy with HSP70 vaccine. Blockade of B7-H1 by i.v. injection pPD-1A, a plasmid encoding the extracellular domain of PD-1 (sPD-1), could reverse this resistance and enhance the therapeutic efficacy. To complement these findings, we investigated the gene expression of tumor-infiltrating lymphocytes (TILs) by Real-time PCR analysis, which revealed that the expression of TH1 cytokines IFN-gamma and IL-2 by TIL in the mice treated with HSP70 vaccine in combination with sPD-1 was increased and the expression of negative regulatory molecules IL-10, TGF-beta and foxp3 was decreased, demonstrating that multifunctional properties afforded by the combination therapy can effectively overcome tumor resistance and promote effective antitumor immunity. The in vivo transfection with pPD-1A could be performed as infrequently as once a week and still produce a significant antitumor effect. These findings suggest that the treatment with HSP70 vaccine followed by blockade of tumor-B7-H1 with sPD-1 may provide a promising approach for tumor immunotherapy.

Animals↗

PubMed2006

Purification of multiwalled carbon nanotubes by annealing and extraction based on the difference in van der Waals potential.

The potential energies of van der Waals interactions between two multiwalled carbon nanotubes (MWNTs) as well as two carbon nanoparticles (CNPs) were calculated and compared on the basis of the continuum Lennard-Jones model. The well depth of the potential is 1 order of magnitude higher for MWNTs than for CNPs, indicating that MWNTs and CNPs can be separated from each other through polymer-induced steric stabilization. On the basis of this prediction, a novel method for the purification of MWNTs was proposed. The method involves a high-temperature annealing (2600 degrees C, 1 h) followed by an extraction treatment with a selected dispersing agent. While the annealing process evaporates the metal particles, the extraction treatment removes CNPs. The quality of the nanotubes obtained after purification was examined by laser Raman, thermogravimetric analysis, and electron microscopy observations.

Journal Article↗

PubMed2006

Decolorization of methyl orange by ozonation in combination with ultrasonic irradiation.

The combination of ultrasound and ozone for the decolorization of azo dye, methyl orange, was studied. The effect of ultrasonic power, ozone gas flow rate, gaseous ozone concentration, initial dye concentration, pH and hydroxyl radical scavenger on the decolorization of methyl orange was investigated. The results showed that the synergistic effect was achieved by combining ozone with ultrasonic irradiation for the decolorization of methyl orange. The synergistic effect was more significant when the system temperature was raised due to the heat effect of ultrasonic irradiation. The decolorization of methyl orange fits the pseudo first order kinetic model. The decolorization rate increased with the increase of ultrasonic power, ozone gas flow rate, gaseous ozone concentration. However, the decolorization rate decreased with the increasing initial dye concentration. Either pH or sodium carbonate has little effect on the decolorization rate, indicating that the low frequency ultrasound enhanced ozonation process for the decolorization of methyl orange is mainly a direct reaction rather than radical reaction.

Azo Compounds↗

PubMed2006

Water-soluble multiwalled carbon nanotubes functionalized with sulfonated polyaniline.

Multiwalled carbon nanotubes (MWNTs) functionalized with a water-soluble conducting polymer, sulfonated polyaniline (SPAN), were prepared by in situ polymerization of aniline followed by sulfonation with chlorosulfonic acid in an inert solvent and by hydrolysis in water. Electron microscopy, laser Raman spectroscopy, X-ray photoelectron spectroscopy, and UV-vis absorption spectroscopy were employed to characterize the morphology and chemical structure of the resulting product. The results show that the quinonoid structure of SPAN preferentially interacts with the nanotubes and is stabilized by strong pi-pi interaction between two components. The structure of MWNTs was not perturbed by the incorporation of SPAN, since the pi-pi interaction between MWNTs and SPAN is much weaker in comparison to that of the carbon covalent bond. The SPAN functionalized MWNTs are highly dispersible in water, thus opening new possibilities for their prospective technological applications.

Journal Article↗

PubMed2006

Mammalian tolloid alters subcellular localization, internalization, and signaling of alpha(1a)-adrenergic receptors.

In the present study, we identified the CUB5 domain of mammalian Tolloid (mTLD) as a novel protein binding to alpha(1A)-adrenergic receptor (AR) using the yeast two-hybrid system. Whereas CUB5 did not couple to either alpha(1B)-AR or alpha(1D)-AR. It was determined that amino acids 322 to 359 of alpha(1A)-AR were the major binding region for CUB5. The direct interaction between alpha(1A)-AR cytoplasmic tail and CUB5 was discovered by glutathione S-transferase pull-down assay. We confirmed the interaction of mTLD with alpha(1A)-AR in human embryonic kidney (HEK) 293 cells by immunoprecipitation, immunofluorescence, and fluorescence resonance energy transfer. Although mTLD did not affect the density and affinity of receptors in crudely prepared membranes from HEK293 cells stably expressing alpha(1A)-AR, it significantly altered the subcellular localization of the receptors. Moreover, mTLD reduced the level of cell surface alpha(1A)-ARs, delayed the initial rate of agonist-induced receptor internalization, and facilitated agonist-induced calcium transient. We have demonstrated that mTLD interacts with alpha(1A)-AR directly, alters the subcellular localization of receptor, and influences agonist-induced alpha(1A)-AR internalization and calcium signaling.

Amino Acid Sequence↗

PubMed2006

Differential restoration of myeloid and plasmacytoid dendritic cells in HIV-1-infected children after treatment with highly active antiretroviral therapy.

Numerical and functional deficits in myeloid (mDC) and plasmacytoid dendritic cell (pDC) subsets have been found in both adult and pediatric HIV-1 carriers. Whether these impaired DC subsets can be restored after treatment with highly active antiretroviral therapy (HAART) is currently unknown, especially in HIV-1-infected children. In this report, we characterized mDC and pDC subsets in 18 HIV-1-infected children who received HAART treatment and compared them with those in 6 untreated HIV-1-infected children and 27 HIV-1-uninfected healthy children. Among children treated with HAART, 11 were found to suppress HIV-1 replication successfully below the detection limit (HAART-suppressed group) while the remaining 7 failed (HAART-failure group). In HAART-suppressed children, a gradual and complete restoration of the frequency and function of mDCs was observed while the recovery of pDCs was only partial. However, mDC and pDC subsets in HARRT failure children were indistinguishable from the HAART-naive infected children. We also found that mDC frequency and IFN-alpha-releasing capacity of pDC positively correlated with CD4 T cell percentages in all HIV-1-infected children. In HAART-naive children, the mDC frequency correlated the HIV-1-specific CTL frequency. Our findings suggest that HAART has a differential impact on the restoration of mDC and pDC subsets. These findings may help guide the development of HIV-1-specific immune therapy aimed at fully restoring host immune function in chronically HIV-1-infected children.

Adolescent↗

PubMed2006

Toxoplasma gondii sequesters lysosomes from mammalian hosts in the vacuolar space.

The intracellular compartment harboring Toxoplasma gondii satisfies the parasite's nutritional needs for rapid growth in mammalian cells. We demonstrate that the parasitophorous vacuole (PV) of T. gondii accumulates material coming from the host mammalian cell via the exploitation of the host endo-lysosomal system. The parasite actively recruits host microtubules, resulting in selective attraction of endo-lysosomes to the PV. Microtubule-based invaginations of the PV membrane serve as conduits for the delivery of host endo-lysosomes within the PV. These tubular conduits are decorated by a parasite coat, including the tubulogenic protein GRA7, which acts like a garrote that sequesters host endocytic organelles in the vacuolar space. These data define an unanticipated process allowing the parasite intimate and concentrated access to a diverse range of low molecular weight components produced by the endo-lysosomal system. More generally, they identify a unique mechanism for unidirectional transport and sequestration of host organelles.

Animals↗

PubMed2006

Langmuir-Blodgett patterning of phospholipid microstripes: effect of the second component.

We systematically describe the striped pattern formation of the mixed monolayers of 1,2-di(2,4-octadecadienoyl)-sn-glycero-3-phosphocholine (DOEPC) and l-alpha-dipalmitoylphosphatidylcholine (DPPC) from the liquid expanded (LE) phase onto a mica surface by Langmuir-Blodgett (LB) transfer. The addition of the second component, DOEPC, strongly affects the formation of DPPC stripe patterns. When the molar ratio of DPPC and DOEPC is 1:0.1, the horizontal stripes dominate, while in the case of pure DPPC monolayer, there are three kinds of patterns: horizontal stripes, grids, and vertical stripes. The width and periodicity of stripes formed from the mixed monolayers are ca. 4-5 times smaller than those formed from pure DPPC patterns at the same transfer conditions, while the widths of channels are similar. A phase shift of substrate-mediated microphase separation in the two-component system during LB transfer is considered to be the mechanism for the influence of the second component on the formation of DPPC stripe patterns.

Journal Article↗

PubMed2006

Hydrothermal synthesis of Zn2SnO4 nanorods in the diameter regime of sub-5 nm and their properties.

Single crystalline Zn(2)SnO(4) (ZTO) nanorods 2-4 nm in diameter and around 20 nm in length were successfully synthesized by a simple hydrothermal process with use of hydrazine hydrate as an alkaline mineralizer instead of NaOH or NH(3).H(2)O. By analyzing the UV-vis diffuse reflectance spectrum, the optical band gap (E(g)) of the nanorods was found to be 3.87 eV, which indicates a blue shift of 0.27 eV from that of bulk ZTO (3.6 eV). In situ high-temperature X-ray diffraction was employed to study the thermal expansion coefficient and the variation of lattice parameter with temperature of the product. Furthermore, we discussed the chemical mechanism and key factors to the hydrothermal formation of the sub-5 nm ZTO nanorods.

Journal Article↗

PubMed2006

Effects of cryptoporus polysaccharide on rat allergic rhinitis associated with inhibiting eotaxin mRNA expression.

Aqueous extract from the fruiting body of Cryptoporus volvatus has been reported to present anti-tumor, anti-allergy, anti-inflammation and immunomodulatory activities. However, the effect mechanisms of anti-allergy and anti-inflammation are poorly understood. The aim of study is to evaluate whether Cryptoporus polysaccharides (CP) extracted from fruiting body of Cryptoporus volvatus decrease the development of nasal symptoms, airway hyperresponsiveness (AHR) to methacholine (MCh) and the infiltration of eosinophils in nasal mucosa in rat model of allergic rhinitis, and investigate a possible action mechanism of CP by detecting the expression of eotaxin mRNA in nasal mucosa and lung tissues. Rats were immunized with ovalbumin and consecutive topical antigen instillation was performed. Repeated intranasal ovalbumin challenge caused rhinitis symptom, AHR to MCh, eosinophil infiltration and histological alterations into the nasal mucosa and increase of eotaxin mRNA expression in nasal mucosa and lung tissue were examined. Pretreatment with CP 3, 9 and 27 mg kg(-1) (ig) decreased the numbers of sneezing 27.4%, 38.4% and 44.3% and nasal rubbing 27.5%, 34.9% and 47.7% comparison with model group, respectively. CP caused a dose-related inhibition of MCh-induced AHR. CP 27 mg kg(-1) decreased the expression of eotaxin mRNA in the nasal mucosa by 35%. These results suggest CP can relieve the symptom, eosinophil infiltration and injury of tissue in nasal mucosa and lung tissue and AHR of allergic rhinitis in rats. Its action mechanism may be associated with the decrease of eotaxin mRNA expression.

Airway Resistance↗