Search PubMed⌕ Search

Biomedical subjects

Hui Liu

Publications and source records attributed to Hui Liu.

At least 145 records · Page 8Linked to original sources
PubMed2004

Cloning and characterization of a novel human zinc finger gene, hKid3, from a C2H2-ZNF enriched human embryonic cDNA library.

To investigate the zinc finger genes involved in human embryonic development, we constructed a C(2)H(2)-ZNF enriched human embryonic cDNA library, from which a novel human gene named hKid3 was identified. The hKid3 cDNA encodes a 554 amino acid protein with an amino-terminal KRAB domain and 11 carboxyl-terminal C(2)H(2) zinc finger motifs. Northern blot analysis indicates that two hKid3 transcripts of 6 and 8.5kb express in human fetal brain and kidney. The 6kb transcript can also be detected in human adult brain, heart, and skeletal muscle while the 8.5kb transcript appears to be embryo-specific. GFP-fused hKid3 protein is localized to nuclei and the ZF domain is necessary and sufficient for nuclear localization. To explore the DNA-binding specificity of hKid3, an oligonucleotide library was selected by GST fusion protein of hKid3 ZF domain, and the consensus core sequence 5'-CCAC-3' was evaluated by competitive electrophoretic mobility shift assay. Moreover, The KRAB domain of hKid3 exhibits transcription repressor activity when tested in GAL4 fusion protein assay. These results indicate that hKid3 may function as a transcription repressor with regulated expression pattern during human development of brain and kidney.

Animals↗
PubMed2004

WDR26: a novel Gbeta-like protein, suppresses MAPK signaling pathway.

WD40 repeat proteins play important roles in a variety of cellular functions, including cell growth, proliferation, apoptosis, and intracellular signal transduction. Mitogen-activated protein kinases (MAPKs) are evolutionary conserved enzymes in cell signal transduction connecting cell-surface receptors to critical regulatory targets within cells and control cell survival, adaptation, and proliferation. Previous studies revealed that G-protein coupled receptors (GPCRs) play important roles in the signal transduction from extracellular stimuli to MAPKs and the WD40-containing Gbeta proteins as well as Gbeta-like proteins are involved in the stimulation and regulation of the MAPK signaling pathways. Here we report the identification and characterization of a novel human WD40 repeat protein, WD40 repeat protein 26 (WDR26). The cDNA of WDR26 is 3,729 bp, encoding a Gbeta-like protein of 514 amino acids in the cytoplasm. The protein is highly conserved in evolution across different species from yeast, Drosophila, mouse, to human. Northern blot analysis indicates that WDR26 is expressed in most of the examined human tissues, especially at a high level in skeletal muscle. Overexpression of WDR26 in the cell inhibits the transcriptional activities of ETS proteins, ELK-1 and c-fos serum response element (SRE), mediated by MEKK1. These results suggest that WDR26 may act as a negative regulator in MAPK signaling pathway and play an important role in cell signal transduction.

Amino Acid Sequence↗
PubMed2004

Chitosan kills bacteria through cell membrane damage.

The bactericidal activity of chitosan (CS) acetate solution against Escherichia coli and Staphylococcus aureus was evaluated by the enumeration of viable organisms at different incubation times. Morphologies of bacteria treated with CS were observed by transmission electron microscopy (TEM). The integrity of the cell membranes of both species and the permeabilities of the outer membrane (OM) and inner membrane (IM) of E. coli were investigated by determining the release from cells of materials that absorb at 260 nm, changes in the fluorescence of cells treated with the fluorescent probe 1-N-phenylnaphthylamine (NPN) and release of cytoplasmic beta-galactosidase activity. In addition, the interaction of CS with synthetic phospholipid membranes was studied using gel permeation chromatography (GPC), UV-VIS spectrophotometery, Fourier-transform infrared spectroscopy (FT-IR) and thermal analysis. Results showed that CS increased the permeability of the OM and IM and ultimately disrupted bacterial cell membranes, with the release of cellular contents. This damage was likely caused by the electrostatic interaction between NH(3)(+) groups of CS acetate and phosphoryl groups of phospholipid components of cell membranes.

Bacterial Outer Membrane Proteins↗
PubMed2004

Dopamine as a robust anchor to immobilize functional molecules on the iron oxide shell of magnetic nanoparticles.

We report on the use of dopamine (DA) as a robust molecular anchor to link functional molecules to the iron oxide shell of magnetic nanoparticles. Using nitrilotriacetic acid (NTA) as the functional molecule, we created a system with an M/Fe2O3-DA-NTA (M = Co or SmCo5.2) nanostructure, which possesses high stability and specificity for separating histidine-tagged proteins. The well-established biocompatibility of iron oxide and the robust covalent bonds between DA and Fe2O3 render this strategy attractive for constructing biofunctional magnetic nanoparticles containing iron oxide.

Dopamine↗
PubMed2004

ZNF411, a novel KRAB-containing zinc-finger protein, suppresses MAP kinase signaling pathway.

Cardiac differentiation involves a cascade of coordinated gene expression that regulates cell proliferation and matrix protein formation in a defined temporo-spatial manner. The zinc-finger-containing transcription factor has been implicated as a critical regulator of multiple cardiac-expressed genes as well as a regulator of inducible gene expression in response to hypertrophic stimulation. Mitogen-activated protein kinase (MAPK) signal transduction pathways are among the most widespread mechanisms of eukaryotic cell regulation. The MAPKs function inside the nucleus and target transcription factors that are prebound to DNA. Many transcription factors are probably important MAPK targets. Here, we have cloned a new zinc-finger gene named ZNF411 using degenerate primers from an early embryo heart cDNA library, which mapped to 19p13.11. The ZNF411 gene consists of 2360 nucleotides and encodes a protein of 499 amino acids with an amino-terminal KRAB domain and eleven carboxy-terminal C2H2 zinc-finger units. Northern blot analysis indicates that a 2.4 kb transcript specific for ZNF411 is expressed in heart, skeletal muscle, and placenta at adult stage and is expressed in most of the examined embryonic tissues, especially at a higher level in skeletal muscle, heart, and pancreas. ZNF411 protein distributes evenly in nuclei when overexpressed in the cells. Reporter gene assays show that ZNF411 is a transcriptional repressor and overexpression of ZNF411 in the COS-7 cells inhibits the transcriptional activities of AP-1 and SRE. These results indicate that ZNF411 is a member of the zinc-finger transcription factor family and may be involved in the heart development, and it probably works as a negative regulator in MAPK signaling pathway.

Amino Acid Sequence↗
PubMed2004

A facile three-component one-pot synthesis of structurally constrained tetrahydrofurans that are t-RNA synthetase inhibitor analogues.

A one-pot procedure for the efficient synthesis of tRNA inhibitor analogues was developed. Thus, three-component 1,3-dipolar cycloaddition reactions of carbonyl ylides derived from diazoindan-1,3-dione and aldehydes with other dipolarophiles in 1,1,2,2-tetrachloroethane in 80 degrees C gave ring-fused tetrahydrofurans having three stereocenters in good yield.

Amino Acyl-tRNA Synthetases↗
PubMed2004

Cyclin D1 activation in B-cell malignancy: association with changes in histone acetylation, DNA methylation, and RNA polymerase II binding to both promoter and distal sequences.

Cyclin D1 expression is deregulated by chromosome translocation in mantle cell lymphoma and a subset of multiple myeloma. The molecular mechanisms involved in long-distance gene deregulation remain obscure, although changes in acetylated histones and methylated CpG dinucleotides may be important. The patterns of DNA methylation and histone acetylation were determined at the cyclin D1 locus on chromosome 11q13 in B-cell malignancies. The cyclin D1 promoter was hypomethylated and hyperacetylated in expressing cell lines and patient samples, and methylated and hypoacetylated in nonexpressing cell lines. Domains of hyperacetylated histones and hypomethylated DNA extended over 120 kb upstream of the cyclin D1 gene. Interestingly, hypomethylated DNA and hyperacetylated histones were also located at the cyclin D1 promoter but not the upstream major translocation cluster region in cyclin D1-nonexpressing, nontumorigenic B and T cells. RNA polymerase II binding was demonstrated both at the cyclin D1 promoter and 3' immunoglobulin heavy-chain regulatory regions only in malignant B-cell lines with deregulated cyclin D1 expression. Our results suggest a model where RNA polymerase II bound at IgH regulatory sequences can activate the cyclin D1 promoter by either long-range polymerase transfer or tracking.

Acetylation↗
PubMed2004

Evidence that the gene encoding ZDHHC8 contributes to the risk of schizophrenia.

Using a relatively dense genetic map of 72 single-nucleotide polymorphisms (SNPs) distributed across the entire 1.5-Mb locus on chromosome 22q11 associated with susceptibilit to schizophrenia, we previously identified two subregions that were consistently associated with the disease. In the distal subregion, we detected an association signal with five neighboring SNPs distributed over a haplotypic block of 80 kb encompassing six known genes. One of these five SNPs, rs175174, had the strongest association of all 72 SNPs that we tested. Here we show that rs175174 regulates the level of the fully functional transcript by modulating the retention of intron 4 of the gene ZDHHC8, which encodes a putative transmembrane palmitoyltransferase. Zdhhc8-knockout mice had a sexually dimorphic deficit in prepulse inhibition, a gene dosage-dependent decrease in exploratory activity in a new environment and a decreased sensitivity to the locomotor stimulatory effects of the psychomimetic drug dizocilpine (MK801). SNP rs175174 shows differences in transmission distortion between sexes in individuals with schizophrenia. Our results indicate that there is an unexpected connection between impaired palmitate modification of neuronal proteins and the psychiatric phenotypes associated with microdeletions of chromosome 22q11.

Acyltransferases↗
PubMed2004

[Evaluation of absolute alcohol treatment for renal cyst with percutaneous puncture and catheterization under ultrasonographic guidance].

OBJECTIVE: To evaluate the effect of absolute alcohol treatment for renal cyst with percutaneous puncture and catheterization. METHODS: This report presented 64 cases of renal cysts, 34 cases were treated with percutaneous puncture (A group) and 30 cases with percutaneous catheterization (B group). According to the size, the cysts were divided into 2 groups, more than 6 cm in diameter and less than 6 cm in diameter. RESULTS: All the patients were followed up for 3 - 12 months by CT or B ultrasonography. Striking difference of the therapeutic results were existed when cystS were more than 6 cm in diameter. CONCLUSION: Percutaneous catheterization is applicable to the sclerosing treatment of renal cyst whose diameter is more than 6 cm.

Adult↗
PubMed2004

DNA damage caused by extracts of chlorinated drinking water in human derived liver cells (HepG2).

Dong (D) lake and the Yangtze (Y) river are the main water supplies of the city of Wuhan, PR China. In the present study, the genotoxic effect of chlorinated drinking water (CDW) processed from raw water of D lake and Y river was evaluated in human HepG2 cells using the Comet assay and the micronucleus test. For that, HepG2 cells were exposed to XAD extracts of CDW corresponding to 0.167, 1.67, 16.7 and 167 ml CDW/ml cell culture. All CDW extracts caused a significant and dose-dependent increase of DNA migration in HepG2 cells. The level of DNA damage varied depending on the sampling time (season) and sampling site. The lowest concentration which caused a significant increase of DNA migration was 1.67 ml CDW/ml culture for water samples collected in August. Water samples collected in March showed their lowest observable effect levels in 167 ml and 16.7 ml CDW/ml culture for Y river and D lake, respectively. Additionally, significant increases of micronuclei (MN) frequencies were found in HepG2 cells after CDW treatment. However, in the MN assay the CDW samples collected in March exhibited higher genotoxicity than the August samples. In conclusion, HepG2 cells provide a useful tool for the detection of genotoxic effects of environmental mixtures.

Comet Assay↗
PubMed2004

Electrophoresis of concentrically and eccentrically positioned cylindrical particles in a long tube.

We study analytically and numerically the electrophoretic motion of cylindrical particles translating slowly in long tubes filled with an electrolyte solution and subjected to axial electric fields. Both thin and thick double layers are considered. Of particular interest is the case when the particle's and tube's radii are of the same order of magnitude. The model accounts for the flow induced by the particle's motion (the particle acts as a leaky piston) and the electroosmotic flow in the tube. The electrophoretic velocity of the particle and the forces and torques acting on it are determined as functions of the particle's radius, length, and position, the particle's and tube's zeta potentials, the tube's length, and the externally imposed pressures. When the particle is positioned off center, it rotates and its trajectory traces an oscillatory path.

Electrophoresis↗
PubMed2004

Effects of chronic administration of PL017 and beta-funaltrexamine hydrochloride on susceptibility of kainic acid-induced seizures in rats.

There is evidence that 5-7 d after acute seizure episodes induced by kainic acid (KA) the rats develop a long-lasting increase in the susceptibility to seizures followed by spontaneous recurrent seizures (SRS). The present study was focused on the role of hippocampal mu opioid receptors (MORs) in the susceptibility of rats to seizures with the KA model of epilepsy. The rats received a convulsant dose of KA (10 mg/kg, i.p.) were continuously infused with a selective MOR agonist PL017 (2.09, 2.59, 3.29 microg/microl), or a selective MOR antagonist beta-funaltrexamine hydrochloride (beta-FNA, 0.88, 1.10, and 1.35 microg/microl) into ventral hippocampus by means of mini-osmotic pumps. Seven days later, the susceptibility of rats to seizures was checked by a subconvulsant dose of KA (5 mg/kg, i.p.). PL017 infusion shortened the latency and increased the stage of seizures induced by subconvulsant dose of KA in a dose-dependent manner. In contrast, infusion of beta-FNA exhibited a dose-dependent effect against seizures challenged by subconvulsant dose of KA. These results indicate that hippocampal MOR may exert a promoting effect on the susceptibility of rats to KA-induced seizures.

Animals↗
PubMed2004

[Effect of raloxifene hydrochloride on bone mineral density, bone metabolism and serum lipids in Chinese postmenopausal women with osteoporosis].

OBJECTIVE: To determine the effect of raloxifene hydrochloride (RLX) on the lumbar spine and total hip bone mineral density (BMD), bone metabolism and serum lipids in Chinese postmenopausal women with osteoporosis. METHODS: 204 Chinese postmenopausal women with osteoporosis from 3 hospitals in Beijing and Shanghai were randomly divided into 2 groups of 102 women: RLX group (RLX of the dosage of 60 mg/day was given for 12 months) and placebo group. In addition, 500 mg of elemental calcium and 200 units of vitamin D were given daily to all women. BMD, serum bone markers and lipids were measured before and after drug administration. The BMD of lumber spine and hip was measured by dual-energy X-ray absorptiometry (DEXA). Serum bone gamma-carboxyglutamic acid-containing protein (BGP) and C-teloppeptide were analyzed by one-step ELISA. Serum lipids were measured by enzymatic method. RESULTS: By the end of the 12-month study period, the lumbar spine BMD was increased by 3.3% +/- 4.8% in the RLX group and 1.0% +/- 4.9% in the placebo group (P < 0.001); the hip BMD was increased by 1.4% +/- 4.8%in the RLX group and decreased by 0.9% +/- 5.0% in the placebo group (P < 0.01). New vertebral fracture occurred in none of the subjects in the RLX group and in 5 subjects of the placebo group (P = 0.059). The serum BGP and CTX decreased by 41.7% and 61.5% respectively in the RLX group, both significantly more than those in the placebo group (10.6% and 35.6% respectively, both P < 0.001). Both the total cholesterol and low-density lipoprotein cholesterol were significantly lower in the RLX group than in the placebo group (both P < 0.001), however, there were no significant differences in high-density lipoprotein cholesterol and triglycerides between these two groups. One subject in the RLX group and 5 subjects in the placebo group discontinued the study due to adverse events. There were no differences in the number of subjects with hot flushes (3 in the RLX group and 1 in the placebo group) and the number of subjects with leg cramps (9 in the RLX group and 4 in the placebo group). No venous thromboembolic event was reported. CONCLUSION: RLX of the dosage of 60 mg/day for 12 months significantly increases the lumbar spine and total hip bone BMD, significantly decreases bone turnover and has favorable effects on serum lipids in Chinese postmenopausal women with osteoporosis.

1-Carboxyglutamic Acid↗
PubMed2004

Long-term outcome of esophageal myotomy for achalasia.

AIM: Modified Heller's myotomy is still the first choice for achalasia and the assessment of surgical outcomes is usually made based on the subjective sensation of patients. This study was to objectively assess the long-term outcomes of esophageal myotomy for achalasia using esophageal manometry, 24-hour pH monitoring, esophageal scintigraphy and fiberoptic esophagoscopy. METHODS: From February 1979 to October 2000, 176 patients with achalasia underwent modified Heller's myotomy, including esophageal myotomy alone in 146 patients, myotomy in combination with Gallone or Dor antireflux procedure in 22 and 8 patients, respectively. Clinical score, pressure of the lower esophageal sphincter (LES), esophageal clearance rate and gastroesophageal reflux were determined before and 1 to 22 years after surgery. RESULTS: After a median follow-up of 14 years, 84.5% of patients had a good or excellent relief of symptoms, and clinical scores as well as resting pressures of the esophageal body and LES were reduced compared with preoperative values (P<0.001). However, there was no significant difference in DeMeester score between pre- and postoperative patients (P=0.51). Esophageal transit was improved in postoperative patients, but still slower than that in normal controls. The incidence of gastroesophageal reflux in patients who underwent esophageal myotomy alone was 63.6% compared to 27.3% in those who underwent myotomy and antireflux procedure (P=0.087). Three (1.7%) patients were complicated with esophageal cancer after surgery. CONCLUSION: Esophageal myotomy for achalasia can reduce the resting pressures of the esophageal body and LES and improve esophageal transit and dysphagia. Myotomy in combination with antireflux procedure can prevent gastroesophageal reflux to a certain extent, but further randomized studies should be carried out to demonstrate its efficacy.

Adolescent↗
PubMed2004

[Development of IgHV family specific nucleic acid vaccine against lymphoma by construction of fusion gene of immunoglobulin heavy chain variable region and cytokine].

OBJECTIVE: To construct the gene co-expression vector of immunoglobulin heavy chain variable region (IgHV) gene and GM-CSF or IL-2 as IgHV family specific nucleic acid vaccine to lymphoma, and study the immune response of the immunized mice against lymphoma. METHODS: Six clones with significantly different length in gene fragments were selected from a gene bank constructed from normal fetal umbilical cord blood. These gene fragments in the clones were sequenced. The sequences were translated into IgHV peptides. T cell epitopes in the IgHV were predicted by bioinformatics. Meanwhile 6 clones of IgHV1 constructed before were analyzed. The most typical clone of IgHV1 and IgHV3 containing most of the T cell epitopes were selected. The IgHV gene fragments whose complementary determining region 3 (CDR3) was cut out and composed mainly of framework region were cloned into eukaryotic expression vector. The gene fragments of framework region of IgHV linking with gene of GM-CSF or IL-2 were cloned into pcDNA3.0 to form fusion genes of IgHV (FR)-GM-CSF/IL-2. Then they were transected into COS cells, African green monkey renal cells, by Lipofectin and their transient expression product was detected by ELISA. Twenty male Balb/c mice were randomly divided into 5 groups of 4 mice to be injected with different vectors at the weeks 0, 2, and 4: with IgHV3 (FR)/pcDNA3.0, with IgHV3 (FR)-IL-2/pcDNA 3.0, with blank vector pcDNA3.0 as control, with IgHV1 (FR)/pcDNA3.0, and with IgHV1 (FR)-IL-2/pcDNA3.0. At the weeks 0, 2, 4, 6, and 8 serum was collected from the mice to undergo indirect immunofluorescence examination to detect the antibodies against Namalwa cells, lymphoma cells from Africa green monkey, and normal lymphocytes. ELISA was used to examine the serum interferon (IFN)-gamma. RESULTS: About 30 of T cell epitopes existed in each IgHV peptides predicted by bioinformatics. Among the bioinformatics prediction, about 90% of the T cell epitopes were in the framework region (FR) of IgHV, and the first 10% with higher prediction score were in FR. The CDR3 of two typical IgHV sequences were cut down and the remaining sequences, mainly composed of FR, were used to construct the IgHV (FR)/pcDNA3.0 expression vectors. The 3' end of IgHV1 (FR) and IgHV3 (FR) were linked to GM-CSF or IL-2 gene successfully. The expression of GM-CSF in the group transfected with IgHV (FR)-GM-CSF/pcDNA3.0 were 200 times higher than in the group transfected with control pcDNA3.0. The expression of IL-2 in the group transfected with IgHV (FR)-IL-2/pcDNA3.0 were 60 times higher than in the group transfected with control pcDNA3.0. The antibody against IgHV1 family lymphoma cell line Namalwa could be detected since the second week in the mice immunized with IgHV1 (FR)-IL-2/pcDNA3.0. The antibody could be detected since the fourth week in the mice immunized with IgHV1 (FR). The antibody against lymphocyte line of IgHV3 family could be detected since the second week in the mice immunized with IgHV3 (FR)-IL-2/pcDNA3.0. The antibody could be detected since the fourth week in the mice immunized with IgHV3 (FR)/pcDNA3.0. The contents of serum IFN-gamma the mice immunized with IgHV1 (FR)-IL-2/pcDNA3.0 and with IgHV3 (FR)-IL-2/pcDNA3.0 was significantly higher than those of the mice immunized with IgHV (FR)/pcDNA3.0 or pcDNA3.0 (all P < 0.01). CONCLUSION: The gene fragments of IgHV (FR) can be used to construct IgHV family specific nucleic acid vaccine that induces anti-lymphoma immune response in mice by muscle injection. The expressing vectors of IgHV (FR)-GM-CSF/IL-2 induces stronger immunoreaction.

Animals↗
PubMed2004

Lamellipodin, an Ena/VASP ligand, is implicated in the regulation of lamellipodial dynamics.

Lamellipodial protrusion is regulated by Ena/VASP proteins. We identified Lamellipodin (Lpd) as an Ena/VASP binding protein. Both proteins colocalize at the tips of lamellipodia and filopodia. Lpd is recruited to EPEC and Vaccinia, pathogens that exploit the actin cytoskeleton for their own motility. Lpd contains a PH domain that binds specifically to PI(3,4)P2, an asymmetrically localized signal in chemotactic cells. Lpd's PH domain can localize to ruffles in PDGF-treated fibroblasts. Lpd overexpression increases lamellipodial protrusion velocity, an effect observed when Ena/VASP proteins are overexpressed or artificially targeted to the plasma membrane. Conversely, knockdown of Lpd expression impairs lamellipodia formation, reduces velocity of residual lamellipodial protrusion, and decreases F-actin content. These phenotypes are more severe than loss of Ena/VASP, suggesting that Lpd regulates other effectors of the actin cytoskeleton in addition to Ena/VASP.

Actins↗