Biomedical subjects

Mei Han

Publications and source records attributed to Mei Han.

At least 19 recordsLinked to original sources

PubMed2007

Livin/ML-IAP as a new target for cancer treatment.

Livin is a member of the inhibitors of apoptosis protein (IAP) gene family, which encodes negative regulatory proteins that prevent cell apoptosis. Livin is selectively expressed in the most common human neoplasms and appears to be involved in tumor cell resistance to chemotherapeutic agents. Several studies in vitro and in vivo have demonstrated that down-regulation of Livin expression increases the apoptotic rate, reduces tumor growth potential and sensitized tumor cells to chemotherapeutic drugs. This review will focus on the role of this protein during cancer development and progression and will demonstrate possible targets for cancer therapy.

Adaptor Proteins, Signal Transducing↗

PubMed2006

New evidence for the involvement of spinal fractalkine receptor in pain facilitation and spinal glial activation in rat model of monoarthritis.

Fractalkine, a chemokine binding to only one known receptor CX3CR1, has recently been proposed to be a neuron-to-glia signal in the spinal cord leading to microglial activation and glially dependent pain facilitation. The previous studies explored that blockade of endogenous fractalkine, using anti-CX3CR1 neutralizing antibody, dose-dependently attenuated neuropathic pain. The present study examined the role of endogenous fractalkine in inflammatory pain. Intra-articular injection of complete Freund's adjuvant (CFA)-induced rat ankle joint monoarthritis (MA) model was used. Western blot analysis revealed that CX3CR1 expression in the spinal cord was significantly increased following CFA-induced MA. Intrathecal injection of anti-CX3CR1 neutralizing antibody both delayed the development of mechanical allodynia and thermal hyperalgesia, and reversed established pain facilitation. Furthermore, blockade of CX3CR1 significantly suppressed activation of spinal glia, especially microglia, evoked by MA. These data provided new evidence for the contribution of endogenous fractalkine to the initiation and early maintenance of inflammatory pain facilitation via activating spinal microglia.

Analysis of Variance↗

PubMed2006

Hyperplasia suppressor gene associates with smooth muscle alpha-actin and is involved in the redifferentiation of vascular smooth muscle cells.

Vascular smooth muscle cell (VSMC) differentiation and phenotypic modulation are characterized by changes in gene expression for smooth muscle (SM) marker contractile proteins such as SM alpha-actin and SM22alpha. Hyperplasia suppressor gene (HSG) is a potent VSMC proliferation-inhibiting factor; however, it is not known if HSG is involved in the redifferentiation of VSMCs. Here, the redifferentiation of the dedifferentiated VSMCs was induced by serum withdrawal or all-trans retinoic acid (atRA), HSG gene expression and its role in VSMC phenotypic modulation were studied by reverse transcription - polymerase chain reaction, Western blotting, and cell migration assay. The results indicated that HSG gene expression increased significantly during VSMC redifferentiation induced by serum deprivation or atRA and peaked at 24 h, then was maintained at higher levels. Meanwhile, SM marker contractile proteins SM alpha-actin and SM22alpha were increased by more than 2-fold. Coimmunoprecipitation and immunofluorescent experiments revealed that anti-HSG antibody could precipitate SM alpha-actin, and HSG and SM alpha-actin colocalized within the cytoplasm of differentiated VSMCs. Migration activity of VSMCs was dramatically suppressed after cells were transfected with HSG expression plasmids. These findings suggested that HSG is associated with SM alpha-actin in VSMC cytoplasm, and is involved in VSMC differentiation and migration.

Actins↗

PubMed2006

Characteristics of equilibrium, kinetics studies for adsorption of fluoride on magnetic-chitosan particle.

The magnetic-chitosan particle was prepared and characterized by the SEM, XRD, FT-IR and employed as an adsorbent for removal fluoride from the water solution in the batch system. The Langmuir isotherms, Bradley's isotherm, Freundlich isotherm and Dubinin-Kaganer-Radushkevich (DKR) isotherm were used to describe adsorption equilibrium. The kinetic process was investigated using the pseudo-first-order model, pseudo-second-order model and intra-particle diffusion model, respectively. The results show that the magnetic-chitosan particle is amorphous of irregular clumps in the surface with groups of RNH(2), RNH(3), Fe-O, etc. Bradley's equation and two-sites Langmuir isotherms were fitted well with the adsorption equilibrium data; the maximal amount of adsorption of 20.96-23.98 mg/l and free energy of 2.48 kJ/mol were obtained from the Bradley's equation, two-sites Langmuir isotherm and DKR modeling, respectively. The pseudo-second-order with the initial adsorption rate 2.08 mg/g min was suitable to describe the kinetic process of fluoride adsorption onto the adsorbent. In overall, the major mechanism of fluoride adsorption onto the heterogeneous surface of magnetic-chitosan particle was proposed in the study.

Adsorption↗

PubMed2006

Skeletal muscle repair in a mouse model of nemaline myopathy.

Nemaline myopathy (NM), the most common non-dystrophic congenital myopathy, is a variably severe neuromuscular disorder for which no effective treatment is available. Although a number of genes have been identified in which mutations can cause NM, the pathogenetic mechanisms leading to the phenotypes are poorly understood. To address this question, we examined gene expression patterns in an NM mouse model carrying the human Met9Arg mutation of alpha-tropomyosin slow (Tpm3). We assessed five different skeletal muscles from affected mice, which are representative of muscles with differing fiber-type compositions, different physiological specializations and variable degrees of pathology. Although these same muscles in non-affected mice showed marked variation in patterns of gene expression, with diaphragm being the most dissimilar, the presence of the mutant protein in nemaline muscles resulted in a more similar pattern of gene expression among the muscles. This result suggests a common process or mechanism operating in nemaline muscles independent of the variable degrees of pathology. Transcriptional and protein expression data indicate the presence of a repair process and possibly delayed maturation in nemaline muscles. Markers indicative of satellite cell number, activated satellite cells and immature fibers including M-Cadherin, MyoD, desmin, Pax7 and Myf6 were elevated by western-blot analysis or immunohistochemistry. Evidence suggesting elevated focal repair was observed in nemaline muscle in electron micrographs. This analysis reveals that NM is characterized by a novel repair feature operating in multiple different muscles.

Animals↗

PubMed2006

Olanzapine differentially affects 5-HT2Aand2C receptor mRNA expression in the rat brain.

This study examined regional changes in rat brain mRNA levels encoding 5-HT(2A) and 5-HT(2C) receptors following chronic olanzapine treatment. The immediate effect (2h after the last treatment) was a down-regulation of 5-HT(2A) receptor mRNA expression, predominantly in the hypothalamus, limbic system and striatum, while a rebound effect was observed 48 h later. 5-HT(2C) receptor mRNA expressions were decreased in the substantia nigra. Correlations between 5-HT(2A) receptor mRNA expression and total food intake, weight gain and energy efficiency were observed.

Analysis of Variance↗

PubMed2006

MICA allele-level typing by sequence-based typing with computerized assignment of polymorphic sites and short tandem repeats within the transmembrane region.

MICA genes are located close to, but are structurally distinct from, HLA class I genes and have been found to be associated with some diseases and with immune responses to transplants. We have developed a MICA typing method based on polymerase chain reaction (PCR)/sequence-based typing and a computer program that determines the polymorphisms and distinguishes the GCT repeats in exon 5. One PCR amplification was performed to obtain templates of 2.2 kb including exons 2, 3, 4, and 5 of MICA to be sequenced with two forward and two reverse primers. Overlay of nucleotide sequencing signals resulting from presence of different GCT repeats in exon 5 antisense from two different MICA alleles can be identified by a computer-based analysis of the combined signal string containing the 35 bases. Eighteen reference samples from the 10th International Histocompatibility Workshop with known MICA alleles, as more recently determined, were tested and the concordance was 100% with the previous typing. In addition, 46 samples from kidney or heart transplant recipients and donors were analyzed for their MICA typing by this approach. Results demonstrated that the majority of samples were MICA heterozygous. The most common allele was MICA*00801/A5.1 (44.7%), which was consistent with previous reports. Three samples manifested ambiguous results, either because of polymorphism in exon 6 which was not tested or because the combination of two alleles gives the same pattern as the other two. The procedure was relatively simple and fast and is presently our method of choice for high-resolution clinical MICA typing.

Alleles↗

PubMed2006

Serum deprivation results in redifferentiation of human umbilical vascular smooth muscle cells.

Phenotypic change of vascular smooth muscle cells (VSMCs) from a differentiated to a dedifferentiated state accompanies the early stage of atherosclerosis and restenosis. Although much progress has been made in determining the molecular mechanisms involved in VSMC dedifferentiation, research on VSMC redifferentiation is hindered by the lack of an appropriate complete redifferentiation model. We established an in vitro model of redifferentiation by using postconfluent VSMCs from human umbilical artery. We demonstrated that serum-deprived VSMCs are capable of complete redifferentiation. After serum deprivation, postconfluent cultured human umbilical VSMCs became elongated and spindle shaped, with elevation of myofilament density, and reacquired contraction. Expressions of VSMC-specific contractile proteins, such as smooth muscle (SM) alpha-actin, SM-myosin heavy chain, calponin, and SM 22alpha, were increased and reached the levels in differentiated cells after serum deprivation. To determine the molecular mechanism of the phenotypic reversion, the levels of expression, phosphorylation, and binding activity of serum response factor (SRF), a key phenotypic modulator for VSMCs, were measured. The results showed that SRF binding activity with CArG motif was significantly increased after serum deprivation, whereas no changes were found in SRF expression and phosphorylation. The increased SRF binding activity was accompanied by an increase in expression of its coactivators such as myocardin. Furthermore, the phenotypic reversion was markedly inhibited by decoy double-strand oligodeoxynucleotides containing SM alpha-actin CArG motif, which was able to competitively bind to SRF. The results suggested that serum deprivation results in redifferentiation of human umbilical VSMCs. This novel model of VSMC phenotypic reversion should be valuable for research on vascular disease.

Cell Differentiation↗

PubMed2006

Research advances on transgenic plant vaccines.

In recent years, with the development of genetics molecular biology and plant biotechnology, the vaccination (e.g. genetic engineering subunit vaccine, living vector vaccine, nucleic acid vaccine) programs are taking on a prosperous evolvement. In particular, the technology of the use of transgenic plants to produce human or animal therapeutic vaccines receives increasing attention. Expressing vaccine candidates in vegetables and fruits open up a new avenue for producing oral/edible vaccines. Transgenic plant vaccine disquisitions exhibit a tempting latent exploiting foreground. There are a lot of advantages for transgenic plant vaccines, such as low cost, easiness of storage, and convenient immune-inoculation. Some productions converged in edible tissues, so they can be consumed directly without isolation and purification. Up to now, many transgenic plant vaccine productions have been investigated and developed. In this review, recent advances on plant-derived recombinant protein expression systems, infectious targets, and delivery systems are presented. Some issues of high concern such as biosafety and public health are also discussed. Special attention is given to the prospects and limitations on transgenic plant vaccines.

Administration, Oral↗

PubMed2006

hhLIM is involved in cardiomyogenesis of embryonic stem cells.

Proteins of the LIM family play important roles in a variety of fundamental biological processes including cell lineage specification and organ development. Here we examined the function in cardiogenesis of a new member of the LIM family, hhLIM, by molecular analysis of early stages of cardiomyocyte differentiation in hhLIM-deficient P19 cell line and P19 cells stably overexpressing hhLIM. The results indicate that hhLIM is a potent transcriptional activator of several cardiac muscle-specific genes. Inhibition of hhLIM expression by antisense transcripts can interfere with expression of cardiac muscle genes and block development of beating cardiomyocytes in P19 embryonic stem cells. Overexpression of hhLIM in P19 cells can enhance expression of cardiac marker genes Nkx2.5 and GATA-4 and potentiate development of cardiomyocyte-like morphology. These findings suggest that, in addition to its role in activation of the cardiac genetic program, hhLIM may be the nuclear target of inductive factor for precardiac cells.

Animals↗

PubMed2006

The clinical effect of herbal magnetic corsets on lumbar disc herniation.

OBJECTIVE: To determine the clinical effects of the treatment of lumbar disc herniation with herbal magnetic corsets. DESIGN: A randomized control trial. SETTING: The outpatient and inpatient departments of the Rehabilitation Center of the West China Hospital. PATIENTS: Sixty patients with clinically diagnosed lumbar disc herniation were included in the study. INTERVENTIONS: Both groups received lumbar traction, medium frequency electrotherapy and massage, whereas the experimental group wore herbal magnetic corsets in addition. MAIN OUTCOME MEASURES: Pain and lumbar function were assessed before treatment and at one week, two weeks and four weeks after intervention. RESULTS: Both groups reported improvements in pain and lumbar function after treatment (P 0.05 or P 0.001). However, the experimental group reported gradually increasing relief over time leading to a better curative effect than observed in the control group (P 0.05 for visual analogue scale or P 0.001 for lumbar function). CONCLUSION: Herbal magnetic corsets can facilitate the reduction of pain caused by lumbar disc herniation and can improve lumbar function. This is a safe and effective non-operative therapeutic option for treatment of lumbar disc herniation.

Adolescent↗

PubMed2006

[Differential response of developing human fetal lung explants to hyperoxia and the effects of dexamethasone on hyperoxia-exposed lungs].

OBJECTIVE: This study aimed to explore the effects of hyperoxia on the development of fetal lung by investigating the changes of morphological and cell proliferation induced by hyperoxia in cultured fetal lungs as well as the effects of dexamethasone on hyperoxia-exposed lungs. METHODS: Human fetal lung explants at the pseudoglandular stage of development were cultured randomly either in normoxia (21% O2/5% CO2) or hyperoxia (95% O2/5% CO2) for 72 hrs. Dexamethasone was added into the feeding medium at the concentration of 10(-6)M. Harvested tissues were stained for pancytokeratin to identify epithelial cells, with Ki-67 as a marker of proliferation. The effects of lung morphometry were analyzed using computer assisted image analysis. The mean airway thickness, the proportion of the surface area occupied by airways, the mean airway surface area and the index of the epithelium proliferation were measured. RESULTS: The lung architectures remained unchanged after 72 hrs normoxia culture, whereas hyperoxia culture resulted in significant dilation of airways and thinning of epithelium, with the surface area of airways of 6662 microm(2) vs 2728 microm(2) and the thickness of airways of 7.8 microm vs 8.1 microm (P < 0.05). Hyperoxia culture also resulted in an increase in the proportion of the surface area occupied by airways than normoxia culture (35.2% vs 23.4%; P < 0.05). The surface area of airways (3174 microm(2)) and the proportion of the surface area occupied by airways (23.9%) decreased significantly in hyperoxia-cultured lungs after dexamethasone administration (P < 0.05). The epithelium proliferation index in hyperoxia-cultured lungs (21.8%) was higher than that in normoxia-cultured lungs (5.1%) and dexamethasone-treated hyperoxia-cultured lungs (7.4%) (P < 0.05). CONCLUSIONS: The exposure of pseudoglandular lungs to hyperoxia modulates the lung architecture to resemble saccular lungs with higher epithelium proliferation index. Dexamethasone may inhibit the effects induced by hyperoxia.

Cell Differentiation↗

PubMed2006

[Expression profile in the cell lines of human TNFAIP1 gene].

TNFAIP1 was first identified as a tumor necrosis factor alpha(TNFalpha) and interleukin-6 (IL-6) inducible protein. Experiments on human and rat suggested the protein may play roles in the DNA repair, DNA synthesis, cell apoptosis and human diseases. But its real function and mechanism have not been reported. In this paper, the expression of TNFAIP1 were determined in a number of cell lines by Real-time PCR. We found that the expression levels of TNFAIP1 are high in COS7 and NIH3T3 cell lines but low in the cancer cell lines. These suggest that TNFAIP1 may be involved in the process of cancer. The over-expression of human TNFAIP1 can accelerate the apoptosis of HeLa cell.

Adaptor Proteins, Signal Transducing↗

PubMed2006

[The role of SM22 alpha in cytoskeleton organization and vascular remodeling].

Phenotypic modulation of vascular smooth muscle cells (VSMCs) plays a key role in vascular remodeling diseases, such as atherosclerosis, hypertension and restenosis. Recent researches have focused on the expression regulation of VSMC-specific marker genes and cytoskeleton organization in association with phenotypic modulation of VSMCs. Smooth muscle 22 alpha (SM22 alpha) is a novel differentiated VSMC marker, which is characterized by its smooth muscle tissue-specific and VSMC phenotype-specific expression pattern, and serves as an actin-association protein to participate in VSMC cytoskeleton organization and vascular remodeling. This article reviews recent advances in the characterization of SM22 alpha structure and its mechanism in VSMC cytoskeleton organization and vascular remodeling.

Cells, Cultured↗

PubMed2006

[Modules biomass structure and growth pattern of Acanthopanax senticosus population in different habitats].

In this paper, a quantitative analysis was conducted on the functional modules' biomass structure and the relationships between biomass allocation and age of Acanthopanax senticosus population in three different habitats of coniferous and broad--leaved mixed forest, Quercus mongolica forest, and secondary miscellaneous forest. The results showed that the individual growth and modules' biomass accumulation of A. senticosus population were closely related to habitat conditions. The mean values of all functional modules' biomass under different ecological environments exhibited the same regularity, i. e. , stem modules > rhizome modules > leaf modules, and there were some similarities in the whole population of A. senticosus. The individual and each module's biomass of the population differed with the canopy density of forests, being larger in Q. mongolica forest with 40% of canopy density than in coniferous and broad-leaved mixed forest and secondary miscellaneous forest. The variations of ramet biomass allocation under different habit conditions indicated the important strategies in growth regulation and biomass allocation, i. e., more biomass was allocated to the leaves preferentially on small ramets, especially in the secondary miscellaneous forest with biggest canopy density, to ensure the full material product. There was the same regulation of heterogeneous speed growth in the relative weight increase of the leaves, stems and ramets of the population under the three habitat conditions.

Biomass↗

PubMed2006

[Fluorescein angiography of retinal neovascularization model in mice].

OBJECTIVE: To investigate a high molecular weight fluorescein angiography in the application of retinal neovascularization model in mouse. METHODS: retinal neovascularization model was induced by exposure mouse to an environment containing high concentration of oxygen. High molecular weight fluorescein isothiocyanate dextran were perfused through the left ventricle directly, then the mouse eyes were enucleated and fixed with 4% paraformaldehyde. The retina was separated from the eyecup and flat mounting was performed on a gelatin coated slide. The vasculature was examined under fluorescent microscope. RESULT: The whole retinal vasculature was clearly visualized under fluorescent microscope. By focusing on different layer of the tissue, superficial, deep vascular plexus and connecting vessels also could be distinguished. The neovascular response occurred at the junction between the vascular and the avascular retina. CONCLUSION: High molecular weight fluorescein angiography can be applied for retinal neovascularization evaluation.

Animals↗

PubMed2006

[Determination of acetylbritannilactone in inulicin and rat plasma by micellar electrokinetic capillary chromatography with on-line sweeping concentration technique].

A method was established for the determination of acetylbritannilactone (ABL) in inulicins and rat plasma by micellar electrokinetic capillary chromatography (MECC), in which on-line sweeping technique was applied to elevate the sensitivity of the detection. The column used was an uncoated fused silica capillary with a size of 57 cm (effective length of 50 cm) x 75 microm i.d. Electrode buffer was a 50 mmol/L borate buffer containing 50 mmol/L sodium lauryl sulfate (SDS) (pH 9.5). Sample buffer was a 10 mmol/L borate buffer (pH 9.5). Other conditions were as follows: separation voltage, 23 kV; detection wavelength, 195 nm; sample injection, 3.45 kPa (0.5 psi) x 5 s; column temperature, 25 degrees C. The on-line sweeping-MECC had excellent linearity with correlation coefficient of 0. 997 5, and reproducibility with the relative standard deviation of ABL migration time less than 5%. The recovery was more than 92%, and the sensitivity was 0.005 g/L. ABL in inulicin and their dynamic change in vivo were determined by sweeping-MECC. The results indicate that on-line sweeping-MECC is a simple and rapid method for the determination of trace biological sample. The method needs only micro-amount of samples, and is characterized by higher degree of automation and sensitivity.

Animals↗

PubMed2005

LOXL null mice demonstrate selective dentate structural changes but maintain dentate granule cell and CA1 pyramidal cell potentiation in the hippocampus.

Lysyl oxidase-like protein (LOXL), part of the lysyl oxidase copper-dependent amine oxidase family, is expressed in the extracellular matrix and in the nucleus. It likely plays a role in cross-linking collagen and elastin, possibly modulating cellular functions. Immunohistochemical studies show the presence of LOXL in the pyramidal cell layer of the hippocampus; and in this study, we report that cells in the granule cell layer have significantly smaller somas in LOXL -/- compared to LOXL +/+ mice. In addition we tested the hypothesis that these structural alterations in the dentate granule layer were associated with synaptic efficacy and thus muted long-term potentiation in mice lacking the protein. Electrical recordings were obtained in 300-mum hippocampal slices in dentate and CA1 pyramidal cell layers in age-matched wild type and LOXL null mice. Potentiation in the CA1 cell layer of 10 LOXL -/- and 8 LOXL +/+ mice was 191.0+/-9.3% and 181.6+/-9.1%, respectively (mean+/-S.E.M.). Dentate potentiation was 120.8+/-7.0% and 121.0+/-3.4% in 11 LOXL -/- and 11 LOXL +/+ mice, respectively. No phenotypic difference in potentiation of population spike amplitude (or in EPSP slope) in either layer was observed. Thus, contrary to expectation, structural changes in the hippocampus of LOXL -/- mice did not affect synaptic remodeling in a manner that impaired the establishment of LTP.

Amino Acid Oxidoreductases↗