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Biomedical subjects

Jun Wu

Publications and source records attributed to Jun Wu.

At least 163 records · Page 9Linked to original sources
PubMed2004

[Identification of wheat and barley hybrid offspring by GISH and PAGE].

Genomic in situ hybridization (GISH) and polyacrylamide gel electrophoresis (PAGE) of wheat seed were used to identify the barley chromosome in offspring of wheat and barley hybrid. A sires of alien addition lines, alien substitution lines and translocation lines were detected by GISH. WBA984 and WBA9812 were alien addition lines, WBS0215 and WBS0264 were alien substitution lines,and WBT02125 and WBT02183 were translocation lines in chromosome terminal. SDS-PAGE analysis and A-PAGE patterns indicated that WBA9812 were 5H alien addition line, WBS0264 was 1 B/5H alien substitution line, and WBT02125 was 1 BL/5HL translocation line.

Chimera↗
PubMed2004

[Study on flavonoids from stem bark of Pongamia pinnata].

Seven flavonoids, pongaflavone (1), karanjin (2), pongapin (3), pongachromene (4), 3,7-Dimethoxy-3', 4'-methylenedioxyflavone (5), millettocalyxin C( 6), 3,3',4', 7-tetramethoxyflavone (7), were isolated from 50% EtOH syrup of the bark of Pongamia pinnata and structureal elucidated on the base of spectral data. Compound 6 was isolated for first time from the plant of the genus Pongamia.

Benzopyrans↗
PubMed2004

[Rapid serum-free culture of dendritic cells from human peripheral blood monocytes and their intracellular signal transduction].

OBJECTIVE: To explore the methods for rapid in vitro culture of the dendritic cells (DCs) from human peripheral blood monocytes (PBMCs) under serum-free conditions and ascertain whether intracellular signal transduction pathway differs between calcium ionophore (CI) and tumor necrosis factor (TNF)- alpha during their induction of dendritic cell differentiation. METHODS: PBMCs isolated from healthy donors were plated in serum-free medium supplemented with 50 ng/ml rhGM-CSF. Cells cultured overnight were induced to differentiate with 100 ng/ml A23187 or 50 ng/ml TNF-alpha, given before or 30 min after pre-treatment with 0.5 mug/ml cyclosporine A (CsA). After culture for 40 h, the cell morphology was observed under phase-contrast microscope, and the surface markers on treated PBMCs were analyzed by flow cytometry. MTT colorimetry was employed to assess the proliferation of the allogeneic T cells. RESULTS: PBMCs of healthy donors treated with 50 ng/ml rhGM-CSF in combination with 100 ng/ml CI or 50 ng/ml TNF-alpha for 40 h exhibited typical morphology of DCs with rapidly decreased CD14 expression and increased expressions of CD83 and co-stimulatory molecules (CD80 and CD86), showing also enhanced ability of stimulating allogeneic T cell proliferation. Calcineurin antagonist CsA inhibited the differentiation induced by CI, but not that induced by TNF-alpha. CONCLUSIONS: Under serum-free conditions, both CI and TNF-alpha are capable of inducing rapid DC differentiation from human PBMCs, but the intracellular signal transduction of CI-induced differentiation is different from that induced by TNF-alpha.

Calcimycin↗
PubMed2004

[Experimental study on the antibacterial effects of zirconium phosphate gauze loaded with silver on the common bacteria on rat burn wound].

OBJECTIVE: To investigate the antibacterial effects of zirconium phosphate gauze loaded with silver on rat burn wounds seeded with commonly seen bacteria. METHODS: Wistar rats were employed in the study and were scalded and infected. The minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) of zirconium phosphate loaded with silver were determined by double dilution in tubes. The effect on wound healing and the subeschar bacterial count of the rat burn wounds were observed after the wounds had been covered by gauze loaded with zirconium phosphate and silver, and also with the gauze which has been rinsed for 20 times. RESULTS: The MIC of silver loaded zirconium phosphate on Staphylococcus aureus, Pseudomonas aeruginosa and E. coli were 8, 8 and 16 mg/L, respectively, while the MBC were 16, 8 and 32 mg/L, respectively. The subeschar bacterial count in the burn wounds with the gauze with silver loaded zirconium phosphate was ten times lower than that in those which were treated with gauze with SD-Ag and 100 times lower than that with ordinary gauze. But there was no difference in the bacterial count between the wounds which were treated with fresh gauze with silver loaded zirconium phosphate and that with the gauze which has been rinsed for 20 times (P > 0.05). Furthermore, wound healing seemed to be better with the gauze with silver loaded zirconium phosphate when compared with those by the other two kinds of gauze. CONCLUSION: The silver loaded zirconium phosphate was found to be bacteriocidal against bacteria commonly seen in the burn wounds.

Animals↗
PubMed2004

[The influence of the application of cytotoxic lymphocyte antigen 4-Ig adenovirus on the burn wounds with alloskin grafting on the murine immune function].

OBJECTIVE: To investigate the influence of local application of cytotoxic lymphocyte antigen 4-Ig (CTLA4-Ig) adenovirus on the burn wound with alloskin grafting upon the murine immune function. METHODS: Sixty BALB/c mice were randomly divided into A (operation control), B (CTLA4-Ig transfection) and C (normal control) groups, with 20 mice in each group. Skin wounds (full-thickness loss) sized 1.5 cm x 1.5 cm were created on the backs of mice in A and B groups. Then the skin grafts of the same size obtained from C57BL mice were grafted into the skin wounds. 0.1 g of cross-linking polyacrylic resin (carbomer cream) without adenovirus was daubed onto the wounds in A group, and the same amount of carbomer cream with adenovirus in titers of 5 x 10(9)/L was daubed onto the wounds in B group, while no treatment was given in C group. 1 ml of 10% SRBC (sheep red blood cell) was injected intraperitoneally to all the mice of the three groups on the 1st post injury day (PID). Splenocytes from BALB/c, C57BL and Kunming mice were harvested for mixed lymphocyte culture on 7, 14, 21 and 28 PIDs. Agglutination assay was used in the same time to detect the SRBC antibody titers. RESULTS: The reaction of murine splenocytes in B group to the donor (C57BL) splenocytes was suppressed in a specific way (P < 0.05) within 14 PIDs. There was no difference in the titers of anti-SRBC antibody among the 3 groups (P > 0.05). CONCLUSION: Local application of CTLA4-Ig recombinant adenovirus exhibited no influence on the murine humoral immunity, but might induce systemic and specific T cell tolerance in immunity system.

Adenoviridae↗
PubMed2003

Inhibition of hepatitis B virus replication by stably expressed shRNA.

The major challenges for anti-hepatitis B Virus (HBV) therapy are the low efficacy of current drugs and the occurrence of drug resistant HBV mutations. A drug with new target sites or independent metabolic pathways may overcome these shortcomings. Small interfering RNA (siRNA) offers the possibility of developing a new anti-HBV therapy. Here we describe the almost complete inhibition of HBV replication by stably expressed 21-mer short hairpin RNAs (shRNA). Besides the conventional targets on HBV reverse-transcriptase, we also systemically targeted other sites of pregenomic RNA, including direct repeat (DR) elements, S, core, and X gene. Our results indicated that shRNAs can serve as efficient alternative anti-HBV agents. They can also be used in combination with chemotherapy, because they showed better effects on the inhibition of HBV replication due to different mechanisms of drug actions.

Carcinoma, Hepatocellular↗
PubMed2003

Repression of p65 transcriptional activation by the glucocorticoid receptor in the absence of receptor-coactivator interactions.

Glucocorticoids are among the most potent antiinflammatory agents, acting through the glucocorticoid receptor (GR) to suppress gene expression of a variety of cytokines. This appears to be via transcriptional interference (or transrepression) of key regulatory factors such as nuclear factor-kappaB and activator protein 1. Ligand-bound GR can also activate gene transcription (transactivation) via direct binding to glucocorticoid response elements. Transactivation by GR is potentiated by accessory coactivators such as steroid receptor coactivator 1 and peroxisome proliferator-activated receptor gamma coactivator 1, whereas the role of these proteins in transrepression is unclear.Here, we show that GR can recruit several coactivator receptor interacting domains in a ligand-dependent manner. All interactions require the charge clamp defined by K579/E755, while a subset also requires a second charge clamp defined by R585/D590, within the GR ligand-binding domain. A point mutation, E755A, abolished all GR-receptor interacting domain interactions and led to a decrease in GR-mediated transactivation, but did not significantly affect GR-mediated transrepression of Gal4-p65 activity. Overexpression of a GR-interacting coactivator peptide blocked transactivation but did not affect transrepression of p65 or TNFalpha-induced IL-6 promoter activity. Finally, the GR antagonist RU486 did not recruit coactivators to GR but maintained the ability to transrepress p65 activity. Our data suggest that different coactivators utilize distinct contact points to interact with GR. Although GR interactions with specific coactivators are critical for transactivation, they appear to be dispensable for at least certain aspects of GR-mediated transrepression of nuclear factor-kappaB. This is consistent with the notion that all GR- mediated repression is not intrinsically linked to activation and can be separated mechanistically.

Amino Acid Sequence↗
PubMed2003

Identification of human intestinal alkaline sphingomyelinase as a novel ecto-enzyme related to the nucleotide phosphodiesterase family.

Alkaline sphingomyelinase (alk-SMase) hydrolyzes dietary sphingomyelin and generates sphingolipid messengers in the gut. In the present study, we purified the enzyme, identified a part of the amino acid sequence, and found a cDNA in the GenBank coding for the protein. The cDNA contains 1841 bp, and the open reading frame encodes 458 amino acids. Transient expression of the cDNA linked to a Myc tag in COS-7 cells increased alk-SMase activity in the cell extract by 689-fold and in the medium by 27-fold. High activity was also identified in the anti-Myc immunoprecipitated proteins and the proteins cross-reacted with anti-human alk-SMase. Northern blotting of human intestinal tissues found high levels of alk-SMase mRNA in the intestine and liver. The amino acid sequence shared no similarity with acid and neutral SMases but was related to the ecto-nucleotide phosphodiesterase (NPP) family with 30-36% identity to human NPPs. Alk-SMase has a predicted signal peptide domain at the N terminus and a signal anchor domain at the C terminus. The ion-binding sites and the catalytic residue of NPPs were conserved, but the substrate specificity domain was modified. Alk-SMase had no detectable nucleotidase activity, but its activity against sphingomyelin could be inhibited by orthovanadate, imidazole, and ATP. In contrast to NPPs, alk-SMase activity was not stimulated by divalent metal ions but inhibited by Zn2+. Differing from NPP2, the alk-SMase cleaved phosphocholine but not choline from lysophosphatidylcholine. Phylogenetic tree indicated that the enzyme is a new branch derived from the NPP family. Two cDNA sequences of mouse and rat that shared 83% identity to human alk-SMase were identified in the GenBank. In conclusion, we identified the amino acid and cDNA sequences of human intestinal alk-SMase, and found that it is a novel ecto-enzyme related to the NPP family with specific features essential for its SMase activity.

Adenosine Triphosphate↗
PubMed2003

Liver X receptors interact with corepressors to regulate gene expression.

Liver X receptors (LXRs) are members of the nuclear receptor superfamily that regulate gene expression in response to oxysterols and play a critical role in cholesterol homeostasis by regulating genes that are involved in cholesterol transport, catabolism, and triglyceride synthesis. Oxysterols and synthetic agonists bind LXRs and activate transcription by recruiting coactivator proteins. The role of LXRs in regulating target gene expression in the absence of ligand is unknown. Here we show that LXRs interact with corepressors, N-CoR (nuclear receptor corepressor) and SMRT (silent mediator of retinoic acid receptor and thyroid receptor), which are released upon binding agonists. The LXR-corepressor interaction is isoform selective, wherein LXRalpha has a very strong interaction with corepressors and LXRbeta only shows weak interaction. LXRs also exhibit a preference for interacting with N-CoR vs. SMRT. Similar to other nuclear receptors, mutations in the LXR helix 3 and 4 region abolish corepressor interaction. Using a transient transfection assay, we demonstrate that LXR represses transcription that can be further increased by cotransfecting N-CoR into cells. Chromatin immunoprecipitation experiments further indicated that N-CoR is recruited onto endogenous LXR target genes, and addition of LXR agonists releases N-CoR from their promoters. Collectively, these results suggest that corepressors play an important role in regulating LXR target gene expression.

Animals↗
PubMed2003

[An experimental study on the effect of Maotai liquor on the liver].

OBJECTIVE: To explore the effect on liver and the mechanism of preventing hepatic fibrosis by drinking Kweichow Moutai liquor (Maotai). METHODS: (1) After ingested with Maotai for 56 days consecutively, the male SD rats were decollated for detecting metallothioneins and MDA content in liver tissues; (2) Culturing rat hepatic stellate cell (HSC) and human HSC in vitro, observing the effect of Maotai on HSC's proliferation and collagen synthesis; (3) After male SD rats were ingested with Maotai for 14 weeks consecutively, the livers were harvested for pathohistological examination. RESULTS: (1) Metallothioneins content in the liver of Maotai-induced rats increased by 22 folds, the production of hepatic lipid peroxide, MDA was significantly decreased (P < 0.05) in Maotai-induced animals suffering from CCL4; (2) Maotai demonstrate obvious inhibitory effect against proliferation of HSC, and the inhibition was concentration-dependent. gene expression and protein secretion of collagens could also be inhibited by Maotai; (3) In control alcoholic group, typical cirrhosis of liver was shaped. In Maotai group, however, though fatty degeneration of hepatocytes and mild fibrosis of interstitium were observed, no obvious hepatic fibrosis and cirrhosis were found. CONCLUSION: It might be an important mechanism of interfering hepatic fibrosis progressing that Maotai induces the increase of metallothioneins content in the liver, inhibits the activation HSC and the synthesis of collagen protein.

Alcoholic Beverages↗
PubMed2003

Ultrarapid nonsuture mated cuff technique for renal transplantation in rabbits.

An effective and ultrarapid technique for kidney transplantation in the rabbit is introduced. Vascular anastomosis was completed using a novel cuff technique in which mating cuffs were used to join the delicate renal vein. The ureter was reconstructed by spatulated end-to-end anastomosis, with special attention to the rabbit's unique ureteral vascular anatomy. The total vascular anastomosis time was 3.4 +/- 1.3 min, and there were no episodes of bleeding or thrombosis. The ureter complication rate was 7.3%. Kidneys transplanted after 5 h of cold storage using the new technique yielded better postoperative creatinine results than similar preserved kidneys transplanted using previously described methods. We suggest this technique for studies of long- and short-term kidney preservation and transplantation in the rabbit, as well as for veterinary transplantation in which donor kidneys must be stored for only a short time before use.

Anastomosis, Surgical↗
PubMed2003

Natural killer cells and cancer.

Natural killer (NK) cells are lymphocytes that were first identified for their ability to kill tumor cells without deliberate immunization or activation. Subsequently, they were also found to be able to kill cells that are infected with certain viruses and to attack preferentially cells that lack expression of major histocompatibility complex (MHC) class I antigens. The recent discovery of novel NK receptors and their ligands has uncovered the molecular mechanisms that regulate NK activation and function. Several activating NK cell receptors and costimulatory molecules have been identified that permit these cells to recognize tumors and virus-infected cells. These are modulated by inhibitory receptors that sense the levels of MHC class I on prospective target cells to prevent unwanted destruction of healthy tissues. In vitro and in vivo, their cytotoxic ability can be enhanced by cytokines, such as interleukin (IL)-2, IL-12, IL-15 and interferon alpha/beta (IFN-alpha/beta). In animal studies, they have been shown to play a critical role in the control of tumor growth and metastasis and to provide innate immunity against infection with certain viruses. Following activation, NK cells release cytokines and chemokines that induce inflammatory responses; modulate monocyte, dendritic cells, and granulocyte growth and differentiation; and influence subsequent adaptive immune responses. The underlining mechanism of discriminating tumor cells and normal cells by NK cells has provided new insights into tumor immunosurveillance and has suggested new strategies for the treatment of human cancer.

Animals↗
PubMed2003

Analysis of orientations of collagen fibers by novel fiber-tracking software.

Recent evidence supports the notion that biological functions of extracellular matrix (ECM) are highly correlated to not only its composition but also its structure. This article integrates confocal microscopy imaging and image-processing techniques to analyze the microstructural properties of ECM. This report describes a two- and three-dimensional fiber middle-line tracing algorithm that may be used to quantify collagen fibril organization. We utilized computer simulation and statistical analysis to validate the developed algorithm. These algorithms were applied to confocal images of collagen gels made with reconstituted bovine collagen type I, to demonstrate the computation of orientations of individual fibers.

Algorithms↗
PubMed2003

The culture and establishment of embryonic germ (EG) cell lines from Chinese mini swine.

As a part of a basic research project on Xeno-transplantion, we have been engaged in the derivation of embryonic stem cell lines from Chinese mini swine. Here, we reported for the first time the establishment of two porcine EG cell lines (BPEG1 and BPEG2) from primordial germ cells of genital ridges of a 28 and a 27 d embryos respectively. Their pluripotent nature has been identified by colony morphology, marker characterization as well as by in vitro and in vivo differentiation. These porcine EG cells are potentially useful for further basic studies.

Alkaline Phosphatase↗
PubMed2003

Modulation of tumor-selective vascular blood flow and extravasation by the stable prostaglandin 12 analogue beraprost sodium.

Improved delivery of macromolecular drugs to solid tumor is known as the enhanced permeability and retention (EPR) effect of macromolecular drugs and lipids. We report here that a prostaglandin I2 (PGI2) analogue induces enhancement of tumor-selective drug delivery, while it decreases tumor blood flow, in a rat tumor model (AH136B). Beraprost sodium (BPS) is an analogue of PGI2 that is more stable than parental PGI2 in vivo (t1/2 for BPS is > 1 h vs. a few seconds for PGI2). Thus, BPS was administered to tumor-bearing rats to examine its effect on tumor vascular permeability as well as tumor blood flow. The amount of extravasation of the Evans blue-albumin complex in tumor tissue increased from two to three times, whereas tumor blood flow decreased almost 70%, in the group treated with BPS at 7 (microg/kg compared with controls. Tissue blood flow of normal organs such as the kidney and the liver did not change to a significant extent. These findings establish a new role for BPS, not only in enhancing macromolecular drug delivery, but also in reducing the blood supply to tumor tissues.

Animals↗
PubMed2003

New aliphatic alcohol and (Z)-4-coumaric acid glycosides from Acanthus ilicifolius.

From the aerial parts of Acanthus ilicifolius, a new aliphatic alcohol glycoside (ilicifolioside C) and two new (Z)-4-coumaric acid glycosides, (Z)-4-coumaric acid 4-O-beta-D-glucopyranoside and (Z)-4-coumaric acid 4-O-beta-D-apiofuranosyl-(1"-->2')-O-beta-D-glucopyranoside were isolated. The structural elucidations were based on the analyses of spectroscopic data. Z-Form 4-coumaric acid glycosides were first isolated from plant.

Acanthaceae↗