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Biomedical subjects

Wei He

Publications and source records attributed to Wei He.

At least 55 records · Page 3Linked to original sources
PubMed2006

[Expression of immune response molecules and function of fas ligand on surface of AML WEHI-3 cells].

The purpose of this study was to investigate the expression of Fas, Fas ligand (FasL) and CD80 and function of FasL on the surface of acute myelomonocytic leukemia cells from WEHI-3 line. The expression of Fas, FasL and CD80 on the surface of WEHI-3 were detected by flow cytometry, the apoptosis of YAC-1 cell induced by FasL on the surface of WEHI-3 were detected by (3)H-TdR incorporation. The results showed that the expression rate of Fas, FasL and CD80 on the surface of WEHI-3 cells were (6.75 +/- 2.31)% (n = 5), (63.73 +/- 5.23)% (n = 5) and (5.06 +/- 0.41)% (n = 5) respectively. The apoptosis rate of YAC-1 cells (target cells) co-cultured with WEHI-3 cells (Effector cells) at the rate of 1:3, 1:10 and 1:30 were (26 +/- 4.5)%, (35 +/- 3.2)% and (43 +/- 2.7)% (n = 5) respectively. It is concluded that WEHI-3 cells have high expression of FasL and low expression of Fas and CD80 on their cell membrane, and can induce the apoptosis of Fas(+) YAC-1 cells.

Apoptosis↗
PubMed2006

[Study on the distribution of lactase in the small intestine of SD rats].

OBJECTIVE: The article deals with the study on the distribution of lactase and its mRNA in the SD rat intestine. METHODS: 15 of the 3-4 wk old SD rats were selected for this research project. From SD rat duodenum, we scissored the small intestine into 3 segments of each 10 cm length to determine the lactase activities and mRNA levels. RESULTS: The lactase activities of all 3 part intestines were declined from the duodenum stage by stage (the upper, middle and lower segment was 0.179, 0.160, or 0.151 U/ml homogenate respectively, P < 0.05), but there were no significant difference of mRNA levels happening among the 3 groups. CONCLUSION: The results suggest that the lactase activity mainly distribute over the upper intestine, although there were lactase along whole intestine.

Animals↗
PubMed2006

[Research on extracting process for compound shenzhutiaozhi capsule].

OBJECTIVE: The technics of optimal extraction for compound shenzhutiaozhi capsule is investigated in this study. METHODS: Orthogonal test were employed for selecting the optimum of extraction technics and the contents of oleanolic acid and salvianolic acid B were detected by TLC-scanning and HPLC, respectively. RESULTS: Five volume of 70% alcohol, extracting 3 times with half an hour for each time, and seven volume of water, extracting 3 times with half an hour for each time were considered the optimum extraction technics of Frugtus Ligustri lucid, Salvie miltiorrhizae as well as Reizaoma Atractylodis Macrocfphalae, respectively. CONCLUSION: The considerable extraction rate of active components in the drugs is achieved by applying the selected technics.

Benzofurans↗
PubMed2006

[Depressing the immune escape of acute myelomonocytic leukemia via an anti-Fas ribozyme].

In order to investigate the inhibition role of anti-Fas hammerhead ribozyme on Fas expression and Fas-mediated apoptosis in CTLL-2 cells (mouse CTL cell line), and to explore a new way for enhancing the ability of T cells against Leukemia in donor lymphocytes infusion, CTLL-2 cells were transfected with pEGFP-RZ596 and pEGFPC1 (mock-transfected) via electroporation. Fas expression on CTLL-2 cells was detected by RT-PCR and Western blot. The killing effect of CTL against WEHI-3 (mouse acute myelomonocytic leukemia cell line) highly expressing FasL in vitro was detected by MTT assay. The caspase-3 proteolytic activity and the apoptosis rate of CTLL-2 cells were detected by means of BD AproAlert Caspase-3 Colorimetric kit and FITC labeled Annexin-V apoptosis detecting kit respectively. The results showed that the anti-Fas ribozyme could be successfully introduced into mouse CTLL-2 cells; Fas expression on the surface of cells transfected with the ribozyme was obviously decreased, in comparison with control and mock-transfected cells; after cocultured with WEHI-3 cells, the viability of CTLL-2 cells transfeced with the ribozyme was significantly increased, as compared with other two groups; caspase-3 activity and apoptosis rate of the ribozyme-transfeced cells were significantly decreased, the killing effect of CTLL-2 transfected with the ribozyme was stronger than that of other groups. It is concluded that anti-Fas ribozyme can remarkably decrease Fas expression on CTLL-2 cells, so as to avoid Fas-mediated apoptosis by Fas ligand on WEHI-3 cells, and to enhance their killing activity against WEHI-3 cells, as a result, the immune escape of acute myelomonocytic leukemia was depressed.

Animals↗
PubMed2006

[Effect of degradable products on degradable property of PGLA in vitro].

In order to investigate the effect of degradable products on degradable property of PGLA in vitro, two kinds of media-PBS and artificial plasma were prepared for immersing PGLA under changing or non-changing media condition. The mass loss rate of PLGA was calculated and the pH value in the non-changing media was measured before and after immersing 2 w, 3 w, 4 w, 6 w, 8 w and 10 w respectively. The results showed that there was almost no statistically significant difference of mass loss rate of PGLA immersing in two kinds of media at 2 w (P > 0.05). But from 2 w to 6 w, the degradation of PGLA immersing in both media under non-changing media group was remarkably faster than those at the same period of changing media group (P < 0.01). During the whole degradable period, the pH value in PBS kept stable around 7.0-7.4, while the pH value in artificial plasma showed gradually decreased as the degradation of PGLA from 7.5 to 5.7. The change of pH values had statistically significant difference between two degradable media (P < 0.01). It was implied that the degradable products existed in immersing media had an effect on degradable speed of PGLA itself if the media was unchanged. It could accelerate the mass loss of material. The pH value also affected the degradable property of PGLA, the lower the pH value, the slower the degradable speed.

Antimicrobial Cationic Peptides↗
PubMed2006

Molecular cloning of a novel cDNA from Mus muscular BALB/c mice encoding glycosyl hydrolase family 1: a homolog of human lactase-phlorizin hydrolase.

OBJECTIVE: To study the mechanism of lactose intolerance (LI) by cloning the mouse lactase cDNA and recombining a vector. METHODS Total murine RNA was isolated from the small intestine of a 4-week-old BALB/c mouse (d). Gene-specific primers were designed and synthesized according to the cDNA sequences of lactase-phlorizin hydrolase (LPH) in human, rat, and rabbit. A coding sequence (CDS) fragment was obtained using RT-PCR, and inserted into a clone vector pNEB-193, then the cDNA was sequenced and analyzed using bioinformatics. RESULTS: The cDNA from the BALB/c mouse with 912 bp encoding 303 amino acid residues. Analysis of the deduced amino acid sequence using bioinformatics revealed that this cDNA shared extensive sequence homology with human LPH containing a conserved glycosyl hydrolase family 1 motif important for regulating lactase intolerance. CONCLUSION: BALB/c mouse LPH cDNA (GenBank accession No: AY751548) provides a necessary foundation for study of the biological function and regulatory mechanism of the lactose intolerance in mice.

Animals↗
PubMed2006

[Variation regularization algorithm in electrical impedance tomography].

In this paper, a variation function has been introduced as a regularization penalty term in electrical impedance tomography (EIT) image restoration, which becomes to be the variation regularization algorithm. The key difference with Tikhonov regularization algorithm is that the variation regularization algorithm not only ensures the inverse problem well-posed but also increase the dividing line between the goal region and the background region of restored image clearer. This made the restored image in good accord with the medical image. It has significance to utilize EIT technique.

Algorithms↗
PubMed2005

[Blocking the escape of leukemic cells from killing of T cell by combining anti-Fas ribozyme and CD80-IgG fusion protein].

OBJECTIVE: To study Fas expression regulation of cytotoxic T lymphocyte(CTL)via anti-Fas ribozyme, increasing of CD80 epitope on the surface of acute myelomonocytic leukemia cells by CD80-IgG fusion protein and their effects on the apoptosis and killing ability against acute myelomonocytic leukemia cells of CTL. METHODS: A hammerhead ribozyme gene targeting the Fas mRNA was synthesized and its expression vector pEGFP-RZ596 was constructed and transfected into the mouse spleen T cells via electroporation. The Fas expression on T cells was detected by RT-PCR and Western bloting. In the meantime the eukaryotic expression vector pcDNA/CD80-IgG was constructed by gene recombinant technique and transfected into ovarian cells of hamster of the line CHO. The CD80-IgG fusion protein was purified from the supernatant of G418-selected CHO cells by Protein G affinity chromatography method. Then allogeneic mixed lymphocytes culture between the mouse spleen T cells transfected with pEGFP-RZ596 and WEHI-3 cells (mouse acute myelomonocyte leukemia cell line) incubated with CD80-IgG fusion protein was performed. The apoptosis rate of the T cells was detected with annexin V-FITC. The proliferation and killing ability in vitro against WEHI-3 cells of the T cells were detected by MTT colorimetry. RESULTS: The luminance of Fas Western bloting results from the mouse spleen T cells negative control, transfected with pEGFPC1 and transfected with pEGFP-RZ596 were separately 1, 0.98 and 0.45 (P < 0.01). After being cocultured with WEHI-3 cells, which has higher expression of Fas ligand (64% +/- 3%), the apoptosis rate and the killing ability against WEHI-3 cells of the mouse spleen T cells transfected with pEGFP-RZ596 were separately 37% and 67%. Whereas that of the mouse spleen T cells negative control and transfected with pEGFPC1 were separately 88%, 84% (P < 0.01) and 32%, 31% (P <0.01). The CD80 positive expression rate of WEHI-3 cells was upregulated from 5.1% +/- 0.4% to 27.4% +/- 2.2% after these cells were preincubated with CD80-IgG fusion protein (P < 0.01). The killing ability of the mouse spleen T cells against WEHI-3 cells preincubated and not preincubated with CD80-IgG fusion protein were separately 64% and 49% (P <0.01), but that of the mouse spleen T cells, which were transfected with pEGFP-RZ596, was further promoted to 82% (P < 0.01) CONCLUSION: The apoptosis of mouse CTL inducing by FasL-Fas pathway could be avoided and the killing ability of mouse CTL against WEHI-3 cells can be significantly promoted at the same time by combining anti-Fas ribozyme and CD80-IgG fusion protein.

Animals↗
PubMed2005

Vdelta1 T cell receptor binds specifically to MHC I chain related A: molecular and biochemical evidences.

Human MHC class I chain-related A (MICA) is a tumor-associated antigen that can be recognized by Vdelta1 subset of tumor-infiltrating gammadelta T cells. We previously reported that immobilized recombinant MICA protein could induce the proliferation of tumor-infiltrating Vdelta1 gammadelta T cells in vitro. But there has been no direct evidence showing the engagement of gammadelta T cell receptors (TCR) of the induced cells with MICA. In the current investigation, we show that MICA induces specific cytolytic activity of the expanded gammadelta T cells. We expressed the coupled V domains from the MICA-induced T cells as a single polypeptide chain Vdelta Vgamma TCR (gammadelta scTCR). Such scTCR can specifically bind MICA of HeLa cells. Direct interaction of gammadelta scTCRs with in vitro expressed MICA was monitored using an IAsys biosensor. We found that the Vdelta1 scTCR can specifically bind to immobilized MICA molecule and MICA alpha1alpha2 domains are responsible for the binding reaction.

Antibodies, Monoclonal↗
PubMed2005

The conserved Leu-724 residue is required for both serine phosphorylation and co-activator recruitment for Stat1-mediated transcription activation in response to interferon-gamma.

The signal transducer and activator of transcription (STAT) proteins, a family of latent cytoplasmic transcription factors, become activated in response to extracellular ligand binding to cell surface receptors through tyrosine phosphorylation. Concurrently, a serine phosphorylation event in the transcription activation domain (serine 727 for Stat1) occurs. This serine phosphorylation is essential for the maximal transcription activity of Stat1. Here we show that, in addition to the Ser-727 residue and its phosphorylation, the conserved Leu-724 residue is also essential for gene activation mediated by Stat1. When Leu-724 is mutated to Ala, phosphorylation of Stat1 Ser-727 is defective both in vivo and in vitro. Surprisingly, we found a StatL724I mutant that lacks transcription activity despite normal Ser-727 phosphorylation. Further analyses show that Leu-724, as well as the phospho-Ser-727, are essential for the recruitment of the transcription co-activator CBP/p300 to the promoters of Stat1 target genes. Our results demonstrate that the conserved Leu-724 residue is a key residue that controls the maximal transcription activities of Stat1 in IFN-gamma signaling.

Base Sequence↗
PubMed2005

In vitro and in vivo two-photon luminescence imaging of single gold nanorods.

Gold nanorods excited at 830 nm on a far-field laser-scanning microscope produced strong two-photon luminescence (TPL) intensities, with a cos(4) dependence on the incident polarization. The TPL excitation spectrum can be superimposed onto the longitudinal plasmon band, indicating a plasmon-enhanced two-photon absorption cross section. The TPL signal from a single nanorod is 58 times that of the two-photon fluorescence signal from a single rhodamine molecule. The application of gold nanorods as TPL imaging agents is demonstrated by in vivo imaging of single nanorods flowing in mouse ear blood vessels.

Animals↗
PubMed2005

SARS coronavirus spike polypeptide DNA vaccine priming with recombinant spike polypeptide from Escherichia coli as booster induces high titer of neutralizing antibody against SARS coronavirus.

Different forms of SARS coronavirus (SARS-CoV) spike protein-based vaccines for generation of neutralizing antibody response against SARS-CoV were compared using a mouse model. High IgG levels were detected in mice immunized with intraperitoneal (i.p.) recombinant spike polypeptide generated by Escherichia coli (S-peptide), mice primed with intramuscular (i.m.) tPA-optimize800 DNA vaccine (tPA-S-DNA) and boosted with i.p. S-peptide, mice primed with i.m. CTLA4HingeSARS800 DNA vaccine (CTLA4-S-DNA) and boosted with i.p. S-peptide, mice primed with oral live-attenuated Salmonella typhimurium (Salmonella-S-DNA-control) and boosted with i.p. S-peptide, mice primed with oral live-attenuated S. typhimurium that contained tPA-optimize800 DNA vaccine (Salmonella-tPA-S-DNA) and boosted with i.p. S-peptide, and mice primed with oral live-attenuated S. typhimurium that contained CTLA4HingeSARS800 DNA vaccine (Salmonella-tPA-S-DNA) and boosted with i.p. S-peptide. No statistical significant difference was observed among the Th1/Th2 index among these six groups of mice with high IgG levels. Sera of all six mice immunized with i.p. S-peptide, i.m. DNA vaccine control and oral Salmonella-S-DNA-control showed no neutralizing antibody against SARS-CoV. Sera of the mice immunized with i.m. tPA-S-DNA, i.m. CTLA4-S-DNA, oral Salmonella-S-DNA-control boosted with i.p. S-peptide, oral Salmonella-tPA-S-DNA, oral Salmonella-tPA-S-DNA boosted with i.p S-peptide, oral Salmonella-CTLA4-S-DNA and oral Salmonella-CTLA4-S-DNA boosted with i.p. S-peptide showed neutralizing antibody titers of <1:20-1:160. Sera of all the mice immunized with i.m. tPA-S-DNA boosted with i.p. S-peptide and i.m. CTLA4-S-DNA boosted with i.p. S-peptide showed neutralizing antibody titers of >or=1:1280. The present observation may have major practical value, such as immunization of civet cats, since production of recombinant proteins from E. coli is far less expensive than production of recombinant proteins using eukaryotic systems.

Administration, Oral↗
PubMed2005

The DNA replication factor MCM5 is essential for Stat1-mediated transcriptional activation.

The eukaryotic minichromosome maintenance (MCM) family of proteins (MCM2-MCM7) is evolutionarily conserved from yeast to human. These proteins are essential for DNA replication. The signal transducer and activator of transcription proteins are critical for the signal transduction of a multitude of cytokines and growth factors leading to the regulation of gene expression. We previously identified a strong interaction between Stat1 and MCM5. However, the physiological significance of this interaction was not clear. We show here by chromatin immunoprecipitation (ChIP) analyses that the MCM5 protein, as well as other members of the MCM family, is inducibly recruited to Stat1 target gene promoters in response to cytokine stimulation. Furthermore, the MCM proteins are shown to move along with the RNA polymerase II during transcription elongation. We have also identified an independent domain in MCM5 that mediates the interaction between Stat1 and MCM5; overexpression of this domain can disrupt the interaction between Stat1 and MCM5 and inhibit Stat1 transcriptional activity. Finally, we used the RNA interference technique to show that MCM5 is essential for transcription activation of Stat1 target genes. Together, these results demonstrate that, in addition to their roles in DNA replication, the MCM proteins are also necessary for transcription activation.

Blotting, Western↗
PubMed2005

Breast cancer bone metastasis mediated by the Smad tumor suppressor pathway.

TGF-beta can signal by means of Smad transcription factors, which are quintessential tumor suppressors that inhibit cell proliferation, and by means of Smad-independent mechanisms, which have been implicated in tumor progression. Although Smad mutations disable this tumor-suppressive pathway in certain cancers, breast cancer cells frequently evade the cytostatic action of TGF-beta while retaining Smad function. Through immunohistochemical analysis of human breast cancer bone metastases and functional imaging of the Smad pathway in a mouse xenograft model, we provide evidence for active Smad signaling in human and mouse bone-metastatic lesions. Genetic depletion experiments further demonstrate that Smad4 contributes to the formation of osteolytic bone metastases and is essential for the induction of IL-11, a gene implicated in bone metastasis in this mouse model system. Activator protein-1 is a key participant in Smad-dependent transcriptional activation of IL-11 and its overexpression in bone-metastatic cells. Our findings provide functional evidence for a switch of the Smad pathway, from tumor-suppressor to prometastatic, in the development of breast cancer bone metastasis.

Animals↗
PubMed2005

Application of dipstick dye immunoassay (DDIA) kit for the diagnosis of schistosomiasis mekongi.

The dipstick dye immunoassay (DDIA), developed in China for the detection of antibodies against Schistosoma japonicum, relies on soluble egg antigen (SEA) labelled with a colloidal dye. This assay is not only rapid, simple and inexpensive, but also particularly useful for screening in the field. In order to determine whether S. japonicum antigens are sufficiently cross-reactive to make the assay applicable for the diagnosis also of S. mekongi a DDIA approach based on the S. japonicum SEA was tried in cohorts of healthy and infected people living in areas non-endemic and endemic with regard to schistosomiasis mekongi in Cambodia and Laos. A sensitivity of 97.1% was recorded when testing Cambodian subjects, correctly diagnosing 33 out of 34 infected people. When the assay was applied in Laos, a sensitivity of 98.6% (69/70) was found. None of 114 residents living in a non-endemic area in Cambodia tested positive. A cross-reaction of 18.3% was found in patients infected with Opisthorchis viverrini. The results support the notion that the DDIA using S. japonicum SEA antigens can safely be implemented for the diagnosis of schistosomiasis mekongi, but care is needed in the interpretation of results obtained from areas that are co-endemic for O. viverrini.

Antibodies, Helminth↗
PubMed2005

Ruthenium(III) chloride catalyzed efficient synthesis of unsymmetrical diorganyl selenides via cleavage of dibenzyl and diphenyl diselenides in the presence of zinc.

[equation: see text] An efficient one-pot route to unsymmetrical diorganyl selenides has been developed by ruthenium(III) chloride catalyzed reactions of dibenzyl or diphenyl diselenides with alkyl halides in the presence of zinc. Organic iodides, bromides, and activated chlorides underwent the reactions efficiently. Unreactive organic chlorides also underwent the same type of selenation with sodium bromide as the additive.

Journal Article↗
PubMed2005

The recognition pattern of gammadelta T cells.

The main function of immune system is to recognize and respond to foreign antigens. During the course of evolution, the body has successfully developed four kinds of mechanisms to recognize antigens, including pattern recognition mediated by macrophages, missing-self and induced-self recognition for NK cells, antigen specific recognition for alphabeta T cells and B cells and "broad-spectrum specific" recognition for gammadelta T cells. The three formers have made great progress these years. However, details of antigen recognition by gammadelta T cells are still mysterious. Gammadelta T cells, a class of T cells only existing in primates, differ from alphabeta T cells in TCR diversity, the structure of TCR-CD3 complex, the tissue distribution, the antigens that they recognize and the way involved in recognition. Here, we shed light on the recognition mechanism of gammadelta T cells against several known antigens and discuss the possible response pattern along the research historical process. We put forward a recognition hypothesis for gammadelta TCR that is conformational recognition based on germline encoded recognition. The key germline encoded amino acids dominate the "putative binding box" and are responsible for recognition. Meanwhile, after gammadelta T cells are activated, several other molecules such as CD69, CD16, 2B4, NKG2D also participate in inducing cytotoxicity of activated gammadelta T cells. Obviously, the illustration of recognition mechanism for gammadelta T cells will help to comprehensively understand the whole immune system and design the higher effective multi-epitope vaccines for tumor and infection immunity.

Animals↗