Biomedical subjects

Jing Yang

Publications and source records attributed to Jing Yang.

At least 127 records · Page 7Linked to original sources

PubMed2005

[Construction of eukaryotic expression vector expressing hepatitis C virus NS5B and EGFP fusion protein and establishment of stable transfected HepG2 cell line].

OBJECTIVE: To construct a eukaryotic expression vector for expressing hepatitis C virus (HCV) recombinant NS5B-EGFP fusion protein and obtain a stable transfected HepG2 cell line. METHODS: The coding region of NS5B gene of HCV was amplified by PCR and was digested by Xho I/Kpn I. This fragment was inserted into pEGFPN3 with T4 ligase and transformed E. coli TG1. The positive recombinant plasmid was selected, then the recombinant plasmid was transfected into HepG2 cell by Lipofectin AMINE 2000. Cells containing stable transformants were selected by the ability of resistance to G418 and isolated with a limited dilution. The stable transfected cell line expressing high level NS5B-EGFP fusion protein was obtained. RESULTS: The eukaryotic expression vector named pEGFPN3-ns5b was successfully constructed and the stable transfected HepG2 cell line expressing NS5B-EGFP fusion protein was obtained. CONCLUSION: The stable transfected HepG2 cell line could express NS5B-EGFP fusion protein, could be used for anti-HCV infection with ns5b gene as the target.

Cell Line, Tumor↗

PubMed2005

[Synthesis, characterization and evaluation of octadecyl ester-bonded monolithic column].

An ester-bonded monolithic silica column for reversed-phase high performance liquid chromatography was synthesized by reacting stearic acid with gamma-glycidoxypropyltrimethoxysilane and coupling the intermediate product onto monolithic silica column. Characterization of the prepared column was carried out with Fourier transformation infrared spectrometry and elemental analysis. The chromatographic properties of the packing were evaluated by using benzene, biphenyl, and anthracene as samples and methanol-water as binary mobile phase. The column back-pressure and separation effect were also evaluated for fast separation. The results show that the stationary phase has satisfactory chromatographic properties and resists hydrolysis between pH = 2 - 8, and it can be used for the fast-separation of solutes efficiently.

Anthracenes↗

PubMed2004

[Reconstruction of periprosthetic fractures of hip with cortical bone plates allografts].

OBJECTIVE: To observe clinical results for reconstruction of periprosthetic fractures of hip with cortical bone plates allografts by deep-freezing and ethylene oxide treatment. METHODS: Seven patients with periprosthetic fractures of hip underwent cortical bone plates allografts by deep-freezing at -70 degrees C after being treatment of 48 degrees C ethylene oxide. And evaluate clinical outcome by examining T lymphocytes, Harris scores, X-rays photograph, and bone scintigraphy. RESULTS: There were not activity of immune rejection and infection in all patients. Harris scores of patients increased 21, 32, 40, 40 scores at 3, 6, 12, 24 months after surgery. T-lymphocytes, antibody and immunocomplex in blood was normal postoperation. X-ray film indicated that fracture was healed at 3 months and there was partially bone conjunction between allograft strut and host bone. There was incorporation of 85% allograft strut to host bone, and 15% allograft strut was partially absorbed at 12 months after surgery. The size of femur of host was added 3 mm to 5 mm, averaged 4.3 mm at 12 months postoperation. Density of 80% allograft plates was as same as host bone after remodeling and the absorbtion of 10% allograft plates stopped at 24 months after surgery. There was thick of nuclein in the area of allograft cortical bone plates by bone scintigraphy examination at 3 months postoperation, and the thick of nuclein was stronger at 6, and 12 months after surgery. CONCLUSION: Allograft cortical bone plates by deep frozen at -70 degrees C after being treatment of 48 degrees C ethylene oxide is suitable for mechanical fixation and biological bone transplantation, and it can increase bone reservation, augment strength of femur once the allograft strut incorporates to host bone, and avoid removing metal implant in second operation when being applied into reconstruction femoral fracture in joint replacement.

Aged↗

PubMed2004

A novel approach to biodegradable block copolymers of epsilon-caprolactone and delta-valerolactone catalyzed by new aluminum metal complexes.

The chemical preparation of structurally well-defined biodegradable amphiphilic block copolymers is now of great interest for biomedical applications and the fundamental mimetic study of biomacromolecule self-assembly. For this purpose, in this study, (R,R)-N,N'-bis(3-tert-butylsalicylidene)-1,2-cyclohexanediamine 2 as a ligand was first synthesized from 1,2-cyclohexanediamine (DACH) and was allowed to further react with AlMe3, leading to a precursor compound 3. Then, the novel five-coordinated aluminum metal complexes 4-6 and 7-8 were prepared with good yields of 80-90%, bearing various molar mass monofunctional methoxy-poly(ethylene glycol) MPEG and difunctional poly(ethylene glycol) PEG as the alkoxy moieties, respectively. By means of nuclear magnetic resonance spectrometry (NMR), mass spectrometry (MALDI-FTMS) and Fourier Transform infrared spectrometry (FT-IR), new metal aluminum complexes 4-8 were characterized as having distinct chemical structures. Utilizing the synthesized metal complexes 4-8 as novel coordination polymerization catalytic templates, biodegradable amphiphilic MPEG-b-PCL, MPEG-b-PVL, PCL-b-PEG-b-PCL and PVL-b-PEG-b-PVL were synthesized with good control of the molecular weight distribution via the ring opening polymerization of epsilon-caprolactone and delta-valerolactone monomers at 100 degrees C in toluene. In addition, the chemical and crystalline structures and the thermal properties of these block biodegradable copolymers were analyzed by means of NMR, gel permeation chromatography (GPC), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). It was found that the melting points and crystallinities of the block copolymers synthesized strongly depended on the molecular structures of the polyether and polyester building blocks. Only one glass transition stage was detected, indicating good chain/segmental miscibility between the hydrophilic MPEG/PEG and hydrophobic PCL/PVL blocks in the non-crystalline regions. Moreover, TGA analysis exhibited typical two-step decomposition profiles with the weight-loss percentages in good agreement with block compositions from NMR calculations.

Aluminum↗

PubMed2004

[An experimental study of cell apoptosis and correlative gene expression after tractive spinal cord injury in rats].

OBJECTIVE: To observe the cell apoptosis after tractive spinal cord injury in rats, determine expression of apoptosis correlative genes, and study the molecular mechanism of cell apoptosis. METHODS: The T(13)-L(2) spinal cord of rats was injured by traction after the amplitude of P1-N1 wave decreased to 70% in postoperation than in preoperation through cortical somatosensory evoked potential (CSEP) monitor. Then rats were killed in 30 min, 6 h, 1, 4, 7, 14 and 21 d respectively after operation (n = 4). Cell apoptosis was examined by the flow cytometer and terminal deoxynucleotidyl transferase-mediated DUTP-biotin nick end labeling (TUNEL) reaction, the expression of p53, bax and bc1-2 genes was tested with immunohistochemistry. RESULTS: The flow cytometer test and TUNEL method showed that the apoptosis cell ratio raised in 6 h and reached at peak in 7 d after injury, and then declined till 21 d, they showed significant difference (P < 0.05, 0.01). TUNEL method showed that injured group had a large number of apoptosis glial cells in white matter. Immunohistochemical staining showed that the positive expression of p53, bax and bc1-2 protein raised at 6 h, expression of p53 protein reached at peak in 4 d, bax and bc1-2 protein reached at peak in 7 d after injury. Compared with control group and laminectomy group, the injured group showed significant difference (P < 0.05, 0.01). CONCLUSION: There is cell apoptosis phenomenon after tractive spinal cord injury in rats. Morphology indicates that apoptosis includes neurons and glialcytes, which is an important form of cell death and pathological changes in secondary lesion period after tractive spinal cord. There exist high expression of apoptosis correlative gene p53 and bax after spinal cord injury, they may play an important role in reduction of cells to apoptosis.

Animals↗

PubMed2004

Molecular basis for TPR domain-mediated regulation of protein phosphatase 5.

Protein phosphatase 5 (Ppp5) is a serine/threonine protein phosphatase comprising a regulatory tetratricopeptide repeat (TPR) domain N-terminal to its phosphatase domain. Ppp5 functions in signalling pathways that control cellular responses to stress, glucocorticoids and DNA damage. Its phosphatase activity is suppressed by an autoinhibited conformation maintained by the TPR domain and a C-terminal subdomain. By interacting with the TPR domain, heat shock protein 90 (Hsp90) and fatty acids including arachidonic acid stimulate phosphatase activity. Here, we describe the structure of the autoinhibited state of Ppp5, revealing mechanisms of TPR-mediated phosphatase inhibition and Hsp90- and arachidonic acid-induced stimulation of phosphatase activity. The TPR domain engages with the catalytic channel of the phosphatase domain, restricting access to the catalytic site. This autoinhibited conformation of Ppp5 is stabilised by the C-terminal alphaJ helix that contacts a region of the Hsp90-binding groove on the TPR domain. Hsp90 activates Ppp5 by disrupting TPR-phosphatase domain interactions, permitting substrate access to the constitutively active phosphatase domain, whereas arachidonic acid prompts an alternate conformation of the TPR domain, destabilising the TPR-phosphatase domain interface.

Acyl Coenzyme A↗

PubMed2004

Insulin and contraction stimulate exocytosis, but increased AMP-activated protein kinase activity resulting from oxidative metabolism stress slows endocytosis of GLUT4 in cardiomyocytes.

Stimulations of glucose transport produced by insulin action, contraction, or through a change in cell energy status are mediated by separate signaling pathways. These are the wortmannin-sensitive phosphatidylinositol 3-kinase pathway leading to the intermediate Akt and the wortmannin-insensitive AMP-activated protein kinase (AMPK) pathway. Electrical stimulation of cardiomyocytes produced a rapid, insulin-like, wortmannin-sensitive stimulation of glucose transport activity, but this occurred without extensive activation of Akt. Although AMPK phosphorylation was increased by contraction, this response was not wortmannin-inhibitable and consequently did not correlate with the wortmannin sensitivity of the transport stimulation. Oxidative metabolism stress due to hypoxia or treatment with oligomycin led to increased AMPK activity with a corresponding increase in glucose transport activity. We show here that these separate signaling pathways converge on GLUT4 trafficking at separate steps. The rate of exocytosis of GLUT4 was rapidly stimulated by insulin, but insulin treatment did not alter the endocytosis rate. Like insulin stimulation, electrical stimulation of contraction led to a stimulation of GLUT4 exocytosis without any marked change in endocytosis. By contrast, after oxidative metabolism stress, no stimulation of GLUT4 exocytosis occurred; instead, this treatment led to a reduction in GLUT4 endocytosis.

Androstadienes↗

PubMed2004

Long hydrocarbon chain keto diols and diacids that favorably alter lipid disorders in vivo.

Keto-substituted hydrocarbons with 11-19 methylene and bis-terminal hydroxyl and carboxyl groups have been synthesized and evaluated in both in vivo and in vitro assays for their potential to favorably alter lipid disorders including metabolic syndrome. Compounds were assessed for their effects on the de novo incorporation of radiolabeled acetate into lipids in primary cultures of rat hepatocytes as well as for their effects on lipid and glycemic variables in obese female Zucker fatty rats [Crl:(ZUC)-faBR] following 1 and 2 weeks of oral administration. The most active compounds were found to be symmetrical with four to five methylene groups separating the central ketone functionality and the gem dimethyl or methyl/aryl substituents. Furthermore, biological activity was found to be greatest in both in vivo and in vitro assays for the tetramethyl-substituted keto diacids and diols (e.g., 10c, 10g, 14c), and the least active were shown to be the bis(arylmethyl) derivatives (e.g., 10e, 10f, 14f). Compound 14c dose-dependently elevated HDL-cholesterol, reduced triglycerides, and reduced NEFA, with a minimum effective dose of 30 mg/kg/day. Compound 1 g dose-dependently modified non-HDL-cholesterol, triglycerides, and nonesterified fatty acids, with a minimum effective dose of 10 mg/kg/day. At this dose, compound 10g elevated HDL-cholesterol levels 2-3 times higher than pretreatment levels, and a dose-dependent reduction of fasting insulin and glucose levels was observed.

Alcohols↗

PubMed2004

Developmental constraint on gene duplicability in fruit flies and nematodes.

A previous study in nematodes suggested that developmental constraint reduces the duplicability of genes involved in early development. Recent large-scale gene expression studies of fly development enabled us to conduct a more detailed study of this issue. We found that the average duplicability of genes involved in embryonic development is indeed lower than that of genes involved in larval development but not significantly lower than that of genes involved in later stages of development. Moreover, in both flies and nematodes genes with multiple expression peaks do not seem to have a lower duplicability than do genes with a single expression peak. Thus, although developmental constraint does appear to reduce gene duplicability, the effect seems weak or at best moderate.

Animals↗

PubMed2004

Long hydrocarbon chain ether diols and ether diacids that favorably alter lipid disorders in vivo.

Long hydrocarbon chain ethers with bis-terminal hydroxyl or carboxyl groups have been synthesized and evaluated for their potential to favorably alter lipid disorders including metabolic syndrome. Compounds were assessed for their effects on the de novo incorporation of radiolabeled acetate into lipids in primary cultures of rat hepatocytes as well as for their effects on lipid and glycemic variables in female obese Zucker fatty rats following 1 and 2 weeks of daily oral administration. The most active compounds were found to be symmetrical with four to five methylene groups separating the central ether functionality and the gem dimethyl or methyl/aryl substituents. Biological activity was found to be greatest for tetramethyl-substituted ether diols (e.g., 28 and 31), while bis(arylmethyl) derivatives (e.g., 10, 11, and 27), diethers (e.g., 49, 50, and 56), and diphenyl ethers (e.g., 35 and 36) were the least active. For the most biologically active compound 28, we observed as much as a 346% increase in serum HDL-cholesterol and a 71% reduction in serum triglycerides at the highest dose administered (100 mg/kg) after 2 weeks of treatment. For compound 31 we observed a 69% reduction in non-HDL-cholesterol, accompanied by a 131% increase in HDL-cholesterol and an 84% reduction in serum triglycerides under the same treatment conditions.

Animals↗

PubMed2004

Genetic mapping of activity determinants within cellular prion proteins: N-terminal modules in PrPC offset pro-apoptotic activity of the Doppel helix B/B' region.

The PrP-like Doppel (Dpl) protein causes apoptotic death of cerebellar neurons in transgenic mice, a process prevented by expression of the wild type (wt) cellular prion protein, PrP(C). Internally deleted forms of PrP(C) resembling Dpl such as PrPDelta32-121 produce a similar PrP(C)-sensitive pro-apoptotic phenotype in transgenic mice. Here we demonstrate that these phenotypic attributes of wt Dpl, wt PrP(C), and PrPDelta132-121 can be accurately recapitulated by transfected mouse cerebellar granule cell cultures. This system was then explored by mutagenesis of the co-expressed prion proteins to reveal functional determinants. By this means, neuroprotective activity of wt PrP(C) was shown to be nullified by a deletion of the N-terminal charged region implicated in endocytosis and retrograde axonal transport (PrPDelta23-28), by deletion of all five octarepeats (PrPDelta51-90), or by glycine replacement of four octarepeat histidine residues required for selective binding of copper ions (Prnp"H/G"). In the case of Dpl, overlapping deletions defined a requirement for the gene interval encoding helices B and B' (DplDelta101-125). These data suggest contributions of copper binding and neuronal trafficking to wt PrP(C) function in vivo and place constraints upon current hypotheses to explain Dpl/PrP(C) antagonism by competitive ligand binding. Further implementation of this assay should provide a fuller understanding of the attributes and subcellular localizations required for activity of these enigmatic proteins.

Alleles↗

PubMed2004

Capillary electrophoresis immunoassay chemiluminescence detection of zeptomoles of bone morphogenic protein-2 in rat vascular smooth muscle cells.

A capillary electrophoresis immunoassay (CEIA) method based on enhanced chemiluminescence (CL) detection was developed and applied to arteriosclerosis pathology research in the medical field. The system of enzyme-horseradish peroxidase (HRP) catalyzing the luminol/H2O2/p-iodophenol reaction was adopted in this paper. HRP was detected with the detection limit (S/N = 3) of 4.4 pM (53 zmol), which represents one of the highest sensitivities of HRP reported yet. HRP was first linked to bone morphogenic protein-2 (BMP-2) in rat vascular smooth muscle (VSM) cells with noncompetitive format and analyzed by CE-CL. HRP-Ab(2)-mAb-BMP-2 complexes can be baseline separated from free HRP in 3 min. The detection limit (S/N = 3) of BMP-2 is 6.2 pM (75 zmol). This technique has been successfully applied to arteriosclerosis development mechanistic study by investigating the change of BMP-2 content in VSM cells, which were stimulated by angiotensin II for different times. The change trends of BMP-2 contents are well in accord with that of the commonly used pathology image analysis system. It proves that the CEIA-CL technique proposed could be developed into a sensitive and new method for clinical assay and pathology research.

Animals↗

PubMed2004

Patterns of segmental duplication in the human genome.

We analyzed the completed human genome for recent segmental duplications (size > or = 1 kb and sequence similarity > or = 90%). We found that approximately 4% of the genome is covered by duplications and that the extent of segmental duplication varies from 1% to 14% among the 24 chromosomes. Intrachromosomal duplication is more frequent than interchromosomal duplication in 15 chromosomes. The duplication frequencies in pericentromeric and subtelomeric regions are greater than the genome average by approximately threefold and fourfold. We examined factors that may affect the frequency of duplication in a region. Within individual chromosomes, the duplication frequency shows little correlation with local gene density, repeat density, recombination rate, and GC content, except chromosomes 7 and Y. For the entire genome, the duplication frequency is correlated with each of the above factors. Based on known genes and Ensembl genes, the proportion of duplications containing complete genes is 3.4% and 10.7%, respectively. The proportion of duplications containing genes is higher in intrachromosomal than in interchromosomal duplications, and duplications containing genes have a higher sequence similarity and tend to be longer than duplications containing no genes. Our simulation suggests that many duplications containing genes have been selectively maintained in the genome.

Chromosome Mapping↗

PubMed2004

[Acetabular reconstruction of total hip replacement in the treatment of dysplastic hip].

OBJECTIVE: To summarize the surgical experience of acetabular reconstruction of total hip replacement in the treatment of dysplastic hip. METHODS: From April 1998 to April 2002, 96 adult cases with osteoarthritis secondary to dysplastic hip were adopted in the study. Among them, there were 89 females and 7 males, age from 27 approximately 68 years. According to Hartofilakidis classification system, there were dysplasia in 73 hips, low dislocation in 18 hips and high dislocation in 21 hips. All patients received total hip replacement, 16 cases with bilateral replacement and 80 cases with unilateral replacement. Kocher-LangenBeck approach was used during operation and all the acetabular cups were reconstructed at the original anatomic location. The fixation methods were as follows: cement cup for 16 hips, cementless cup for 96 hips and bone graft in 11 hips. The reconstructive methods were as follows: regular replacement for 83 hips; installing a smaller cup after deeper reaming the acetabulum for 27 hips; installing a smaller cup after autofemoral grafting on the superior lip for 2 hips. RESULTS: The incision healed primarily and no infection or nerve injury occurred. Follow-up for 1 approximately 5 years (average for 3.5 years) in 85 patients, the Harris score increased from 33.9 preoperatively to 89.3 postoperatively, and 95 hips had good or excellent clinical results. Radiographically, the positions of the prostheses were normal, the average abduction angle of the cup was 44 degrees, the average superolateral bone coverage of the hips was 96.6%, no radiolucent line was observed at the acetabular side. All the bone grafts fused with the host bone successfully. CONCLUSIONS: Total hip replacement is an effective operation in the treatment of osteoarthritis secondary to dysplastic hip. The four specific factors that should be considered in acetabular reconstruction are: (1) the surgical approach, (2) the reconstructive position of the acetabulum, (3) the reconstructive method of the acetabulum, (4) the leg-length discrepancies. It's a challenging to the orthopaedic surgeon. Careful preoperative preparation is recommended.

Adult↗

PubMed2004

Prp8 intein in fungal pathogens: target for potential antifungal drugs.

Inteins are self-splicing intervening sequences in proteins, and inteins of pathogenic organisms can be attractive drug targets. Here, we report an intein in important fungal pathogens including Aspergillus fumigatus, Aspergillus nidulans, Histoplasma capsulatum, and different serotypes of Cryptococcus neoformans. This intein is inside the extremely conserved and functionally essential Prp8 protein, and it varies in size from 170 aa in C. neoformans to 819 aa in A. fumigatus, which is caused by the presence or absence of an endonuclease domain and a putative tongs subdomain in the intein. Prp8 inteins of these organisms were demonstrated to do protein splicing in a recombinant protein in Escherichia coli. These findings revealed Prp8 inteins as attractive targets for potential antifungal drugs to be identified using existing selection and screening methods.

Amino Acid Sequence↗

PubMed2004

Twist, a master regulator of morphogenesis, plays an essential role in tumor metastasis.

Metastasis is a multistep process during which cancer cells disseminate from the site of primary tumors and establish secondary tumors in distant organs. In a search for key regulators of metastasis in a murine breast tumor model, we have found that the transcription factor Twist, a master regulator of embryonic morphogenesis, plays an essential role in metastasis. Suppression of Twist expression in highly metastatic mammary carcinoma cells specifically inhibits their ability to metastasize from the mammary gland to the lung. Ectopic expression of Twist results in loss of E-cadherin-mediated cell-cell adhesion, activation of mesenchymal markers, and induction of cell motility, suggesting that Twist contributes to metastasis by promoting an epithelial-mesenchymal transition (EMT). In human breast cancers, high level of Twist expression is correlated with invasive lobular carcinoma, a highly infiltrating tumor type associated with loss of E-cadherin expression. These results establish a mechanistic link between Twist, EMT, and tumor metastasis.

Animals↗

PubMed2004

Synthetic two-piece and three-piece split inteins for protein trans-splicing.

Inteins are protein-intervening sequences that can self-excise and concomitantly splice together the flanking polypeptides. Two-piece split inteins capable of protein trans-splicing have been found in nature and engineered in laboratories, but they all have a similar split site corresponding to the endonuclease domain of the intein. Can inteins be split at other sites and do trans-splicing? After testing 13 split sites engineered into a Ssp DnaB mini-intein, we report the finding of three new split sites that each produced a two-piece split intein capable of protein trans-splicing. These three functional split sites are located in different loop regions between beta-strands of the intein structure, and one of them is just 11 amino acids from the beginning of the intein. Because different inteins have similar structures and similar beta-strands, these new split sites may be generalized to other inteins. We have also demonstrated for the first time that a three-piece split intein could function in protein trans-splicing. These findings have implications for intein structure-function, evolution, and uses in biotechnology.

Escherichia coli↗

PubMed2004

Mer receptor tyrosine kinase signaling participates in platelet function.

OBJECTIVE: Recently, mice made deficient in growth arrest-specific gene 6 product (Gas6) or in which Gas6 gene expression was inhibited were shown to have platelet dysfunction and to be less susceptible to thrombosis. The aim of this study was to define and characterize the relevant Gas6 receptor or receptors involved in platelet function. METHODS AND RESULTS: Using RT-PCR and Western blot analysis we found that mer was the predominantly expressed subtype in mouse and human platelets, whereas axl and rse were not detected. We generated mer-deficient mice by targeted disruption of the mer receptor gene. Platelets derived from mer-deficient mice had decreased platelet aggregation in responses to low concentrations of collagen, U46619, and PAR4 thrombin receptor agonist peptide in vitro. However, the response to ADP was not different from wild-type platelets. Knockout of the mer gene protected mice from collagen/epinephrine-induced pulmonary thromoembolism and inhibited ferric chloride-induced thrombosis in vivo. Tail bleeding times, coagulation parameters, and peripheral blood cell counts in mer-deficient mice were similar to wild-type mice. CONCLUSIONS: Our data provide the first evidence that mer, presumably through activation by its ligand Gas6, participates in regulation of platelet function in vitro and platelet-dependent thrombosis in vivo.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗