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Biomedical subjects

L Yu

Publications and source records attributed to L Yu.

At least 109 records · Page 6Linked to original sources
PubMed2001

[beta-elemene induces apoptosis of K562 leukemia cells].

OBJECTIVE: To investigate the apoptosis-inducing effect of beta-elemene on K562 leukemia cells. METHODS: Hoechst 33342 and PI fluorescence staining, DNA fragmentation, electron microscopy, flow cytometry, and immunocytochemistry were used to evaluate the effect of beta-elemene on K562 cells. RESULTS: beta-elemene heatment induced the formation of apoptotic bodies and DNA ladder. The effect was dose- and time-dependent. The expression of bcl-2 was decreased in beta-elemene treated cells as compared with the untreated control cells. CONCLUSION: beta-elemene exerts its cytotoxic effect on K562 leukemic cells by the induction of apoptosis.

Apoptosis↗
PubMed2001

[Internal strontium-89 radiotherapy for malignant bony metastasis].

OBJECTIVE: This work was done to evaluate the indication, effectiveness, and side effects of internal radiotherapy with radioactive nuclide strontium-89 (89Sr) in patients with malignant metastasis in the bone. METHODS: Fifty-six patients with skeletal metastasis received this internal radiotherapy. The patients were observed and followed up with respect to pain control, lesion improvement and side effects. RESULTS: The overall effective rate of pain control was 76.8% with the effective rate of prostatic cancer and breast cancer higher than 80%. The lesions in 81.8% patients as assessed by SPECT imaging, were improved. The mild lowering of white cells, platelets and red cells was the main side effect. CONCLUSION: Internal radiotherapy with 89Sr is very useful for patients with malignant cancer metastasis in the bone.

Adult↗
PubMed2001

[p15 gene expression in acute lymphoblastic leukemia cell line Molt4 induced by arsenic trioxide].

OBJECTIVE: To explore the correlation between arsenic trioxide and gene methylation in an acute lymphoblastic cell line. METHODS: Methylation of p15 gene in Molt4 cell line was detected by polymerase chain reaction (PCR) using methylation specific primer (MSP) and the expression of this gene after arsenic trioxide treatment was detected by reverse transcriptase PCR (RT-PCR). The cell cycle and cell growth curve were also observed by flow cytometry. RESULTS: p15 gene failed to express in molt4 after methylation. The expression was recovered, cell growth was inhibited, and G(1) cell cycle arrest was observed, when the cells exposed to arsenic. CONCLUSION: Arsenic trioxide could activate the expression of p15 gene and reverse cell cycle negative regulation.

Acute Disease↗
PubMed2001

A chronic inflammatory infusion model of peritoneal dialysis in rats.

OBJECTIVES: Peritoneal membrane changes are related to daily exposure to non physiologic dialysate and recurrent acute inflammation. We modified a daily infusion and inflammation model and evaluated it for fibrotic and angiogenic features. The feasibility of adenovirus-mediated gene transfer in the model was also assessed. METHODS: Peritoneal catheters were implanted in rats. Over a period of 4 weeks, the animals received a daily infusion of Dianeal 4.25% (Baxter Healthcare Corporation, Deerfield, IL, U.S.A.) with an initial three doses of lipopolysaccharide (LPS) or physiologic saline. Peritoneal fluid was assayed for transforming growth factor beta (TGFbeta) and vascular endothelial growth factor (VEGF). Animals were humanely killed at week 5. Net ultrafiltration was then measured, and tissue samples were immunostained for factor VIII. Mesenteric tissue was assayed for hydroxyproline content. Adenovirus-mediated gene transfer of beta-galactosidase was assayed by intraperitoneal administration of the virus, 4 days before the end of the experiment. RESULTS: Animals treated with either Dianeal or physiologic saline showed peritoneal membrane thickening and increased vascularity. Fibrosis was demonstrated by increased hydroxyproline concentration. Ultrafiltration was impaired. We found increased concentrations of VEGF and TGFbeta in the peritoneal fluid of animals treated with LPS and daily infusion. Adenovirus-mediated gene transfer to the peritoneal membrane was demonstrated in the model. CONCLUSIONS: Exposure to LPS and daily Dianeal or physiologic saline leads to peritoneal fibrosis and neoangiogenesis. Vascularization and glucose transport correlate with ultrafiltration failure. The present animal model mimics changes seen in humans on peritoneal dialysis and may be valuable for evaluating short-term interventions to prevent membrane damage.

Adenoviridae↗
PubMed2001

[Enhanced immunogenicity of plasmid encoding polyprotein gene of infectious bursal disease virus by co-administration of chicken interleukin 2 (IL-2)].

Chicken interleukin 2 (IL-2) is one of important nonmammalian cytokines isolated recently. The influencing of IL-2 on immunogenicity of DNA vaccine was examined using infectious bursal disease virus as a model. The IL-2 cDNA of Xiaoshan chicken and the polyprotein gene of IBDV-ZJ2000 were amplified by RT-PCR, cloned, sequenced and inserted into the control of CMV promoter and enhancer of pCI vector. 14-day-old chickens were vaccinated intramuscularly with DNA vaccine, two weeks later, they were boosted with DNA, and two weeks post boost, they were challenged with virulent IBDV. The results showed that protective responses and neutralization antibody responses of DNA vaccine co-administrated with chicken IL-2 were much higher than those of injected with DNA vaccine alone. Furthermore, the T lymphocyte proliferation response of peripheral blood, thymus and spleen, and the B lymphocyte proliferation response of bursa induced by DNA vaccine can be significantly enhanced by chicken IL-2. These results obviously indicated that chicken IL-2 was a strong adjuvant which can significantly enhance the immunogenicity of IBDV DNA vaccine.

Animals↗
PubMed2001

[An exploration of animal behavior screen platform for novel gene function in central nervous system].

For the purpose of large-scale screening of novel gene functions in mammalian nervous system, we have developed an animal behavior-monitoring platform employing antisense-oligo technology. Twenty genes of different categories were chosen from a low abundant gene (c)DNA sub-library of rat brain. Antisense oligo-nucleotides of these genes were designed and synthesized according to the homologues of the genes in mouse for mouse behavior tests. These antisense oligos were injected into the lateral ventricles of mouse brain using a Hamilton micro-syringe, with saline and oligos of scramble sequences as controls. These mice were tested with the following behavior model paradigms: metabolism, open field behavior, tail flick latency, and step-down test. Out of the 20 genes tested, 14 genes showed significant behavioral differences from the control groups at the level of P value less than 0.05 or 0.001 in different behavior animal models.

Animals↗
PubMed2001

Cloning and Phylogenetic Analysis of Interleukin-2 Gene in Xiaoshan Chicken, A Chinese Local Chicken Breed.

Chicken interleukin 2 (cIL-2) is one of important nonmammalian cytokines isolated recently. In this paper, optimum condition for production of chicken IL-2 in vitro was developed. Isolation of spleen lymphocytes from Xiaoshan chicken, activation by ConA, followed by RT-PCR in a single step, resulted in the synthesis of chicken IL-2 cDNA. The full-length chicken IL-2 cDNA was 737 bp, encoding a 143 amino acids precursor. Only 1--5 amino acid difference were found compared with other three published chicken IL-2s. This IL-2 shared 69.4% homology with turkey IL-2 and shared 21.2%--9.4% homology with mammalian IL-2. The predicted protein had a leader sequence composed of 22 amino acids, and four conversed cysteines allowing the formation of two intrachain disulfide bonds. There were four regions of heptad repeats, with hydrophobic amino acids at positions 1 and 4, were presumably forming amphipathic alpha-helices. These regions were equivalent to mammalian helices A, B, C and D. The amino acids at positions 40(D), 65(Y), 82(E), 108(N) and 142(Q) might play roles in binding to receptors of chicken IL-2. Phylogenetic tree analysis indicated that the chicken IL-2 may have evolutionary relationship with mammalian IL-2 they showed however species difference in function because of selective pressure of immune systems.

Journal Article↗
PubMed2001

[Plasma cell granuloma of maxillary sinuses].

OBJECTIVE: To study the clinical features and treatment of plasma cell granuloma in maxillary sinuses. METHOD: The clinical information of 3 cases was reported and the literatures were also reviewed. RESULT: All of the 3 cases were cured after Caldwell-Luc operation combined with oral corticosteroids and antiallergic agent. Recurrence hasn't been found in half to 2 years follow-up period. CONCLUSION: Plasma cell granuloma of maxillary sinus is a chronic inflammatory lesion with unknown origin. In almost all of the cases, CT images showed some degree of involvement of the bony wall of the maxillary sinuses. The imaging findings mimicker malignant tumors. But the prognosis were quite well in most of the patients.

Combined Modality Therapy↗
PubMed2001

[Genomic structure and proteins sequence analysis of full-length of segment A of three infections bursal disease viruses].

The full-length of segment A of three infectious bursal disease viruses (IBDV), including an attenuated strain HZ2, an attenuated vaccine strain JD1 and a virulent field isolate ZJ2000, were cloned by long RT-PCR and sequenced respectively. All the three results revealed the identity of IB-DV with two overlapping open reading frames (ORF) flanked by 5'- and 3'-noncoding regions(NCR) in 3259 bp long. The strains shared high identity with each other at nucleotide or deduced amino acid level, and also had four unique sites H253, N279, T284, R330 which are common in other attenuated and some classic or highly virulent strains. The virulent strain ZJ2000 had several key amino acid mutations located in hypervariant region of VP2 and near the VP2-VP4 cleavage site of polypeptide, which is probably related to the virulence. Sequence comparison supported that VP2 is not the sole determinant of the virulence. The highly conservation in 5'- and 3'-NCR of different strains indicated the NCR may be not responsible for the virulence. But the same conservation appeared in VP5 revealed another complex relationship between VP5 and the virulence.

Amino Acid Sequence↗
PubMed2001

The preliminary experimental study of induced differentiation of embryonic stem cells into corneal epithelial cells.

PURPOSE: To study preliminarily induced differentiation of embryonic stem cells into corneal epithelial cells in vitro. METHODS: Murine embryonic stem cells were co-cultured with Rabbit limbal corneal epithelial cells in Transwell system to induce differentiation. Mophological and immunohistochemical examination were implemented. RESULTS: The induced cells from embryonic stem cells have an epithelial appearance. The cells formed a network and were confluent into film gradually after being co-cultured with rabbit limbal corneal epithelial cells for 24-96 hours. The cells ranged mosaic structure and localized together with clear rim. Most of the cells showed polygonal appearance. Transmission electron microscope showed lots of microvilli on the surface of induced cells and tight junctions between them. These epithelial-like cells expressed the corneal epithelial cell specific marker cytokeratin3/cytokeratin12. CONCLUSION: The potential mechanism of the differentiation of murine embryonic stem cells into corneal epithelial cells induced by limbal corneal epithelial cell-derived inducing activity is to be further verified.

Animals↗
PubMed2001

[Study on antitumor effect and mechanism of aloe polysaccharides].

OBJECTIVE: To study the antitumor activity and mechanism of aloe polysaccharides (AP). METHODS: AP was administered i.p. or i.v. to Sarcoma 180(S180) bearing mice or Hepatoma22(H22) bearing mice solely or combining with CTX, FU and ADM respectively. 10 days later, for S180 mice, the blood was analyzed, the tumor was peeled off and weighed, and the spleen index, thymus index was calculated. For H22 bearing mice, the survival rate was observed or the IL-2, TNF content in serum was tested. RESULTS: 25 mg/kg.d or 50 mg/kg.d AP group could evidently reduce the tumor weight of S180 bearing mice and prolong the survival time of H22 bearing mice. AP also could improve the antitumor effects of CTX, ADM, FU, and lessen the chemotherapy side-effects. Furthermore, AP could improve the level of IL-2, TNF in the serum of mice bearing S180 or H22. CONCLUSION: AP has the effects of antitumor, enhancing the antitumor activity of chemotherapy drugs and lessening their side-effects. This effect was possibly derived from inducing IL-2 and TNF producing in body and improving the immunity activity.

Aloe↗
PubMed2001

[Auricular cartilage palisade technique for repairing tympanic membrane perforation].

OBJECTIVE: To study the auricular cartilage palisade technique for repairing tympanic membrane perforation. METHOD: Sixty-six cases of large tympanic membrane perforation were treated with auricular cartilage. The results were compared with that of temporal fascia repairing in 60 ears. RESULTS: The closure rates of tympanic membrane perforation were 92.4% in cartilage group and 80% in temporal fascia group, respectively. There was no significant difference between two groups in hearing improvement. The cartilage is quite suitable for repairing large perforation of the tympanic membrane and for treating adhesive otitis media. CONCLUSION: The auricular cartilage palisade technique is an ideal method for repairing tympanic membrane perforation.

Adult↗
PubMed2000

Human glial cell line-derived neurotrophic factor receptor alpha 4 is the receptor for persephin and is predominantly expressed in normal and malignant thyroid medullary cells.

Glial cell line-derived neurotrophic factor (GDNF) family ligands signal through receptor complex consisting of a glycosylphosphatidylinositol-linked GDNF family receptor (GFR) alpha subunit and the transmembrane receptor tyrosine kinase RET. The inherited cancer syndrome multiple endocrine neoplasia type 2 (MEN2), associated with different mutations in RET, is characterized by medullary thyroid carcinoma. GDNF signals via GFRalpha1, neurturin via GFRalpha2, artemin via GFRalpha3, whereas the mammalian GFRalpha receptor for persephin (PSPN) is unknown. Here we characterize the human GFRalpha4 as the ligand-binding subunit required together with RET for PSPN signaling. Human and mouse GFRalpha4 lack the first Cys-rich domain characteristic of other GFRalpha receptors. Unlabeled PSPN displaces (125)I-PSPN from GFRA4-transfected cells, which express endogenous Ret. PSPN can be specifically cross-linked to mammalian GFRalpha4 and Ret, and is able to promote autophosphorylation of Ret in GFRA4-transfected cells. PSPN, but not other GDNF family ligands, promotes the survival of cultured sympathetic neurons microinjected with GFRA4. We identified different splice forms of human GFRA4 mRNA encoding for two glycosylphosphatidylinositol-linked and one putative soluble isoform that were predominantly expressed in the thyroid gland. Overlapping expression of RET and GFRA4 but not other GFRA mRNAs in normal and malignant thyroid medullary cells suggests that GFRalpha4 may restrict the MEN2 syndrome to these cells.

Animals↗
PubMed2000

Confirmation of the involvement of protein domain movement during the catalytic cycle of the cytochrome bc1 complex by the formation of an intersubunit disulfide bond between cytochrome b and the iron-sulfur protein.

To study the essentiality of head domain movement of the Rieske iron-sulfur protein (ISP) during bc(1) catalysis, Rhodobacter sphaeroides mutants expressing His-tagged cytochrome bc(1) complexes with three pairs of cysteines engineered (one cysteine each) on the interface between cytochrome b and ISP, A185C(cytb)/K70C(ISP), I326C(cytb)/G165C(ISP), and T386C(cytb)/K164C(ISP), were generated and characterized. Formation of an intersubunit disulfide bond between cytochrome b and ISP is detected in membrane (intracytoplasmic membrane and air-aged chromatophore), and purified bc(1) complex was prepared from the A185C(cytb)/K70C(ISP) mutant cells. Formation of the intersubunit disulfide bond in this cysteine pair mutant complex is concurrent with the loss of its bc(1) activity. Reduction of this disulfide bond by beta-mercaptoethanol restores activity, indicating that mobility of the head domain of ISP is functionally important in the cytochrome bc(1) complex. The rate of intramolecular electron transfer, between 2Fe2S and heme c(1), in the A185C(cytb)/K70C(ISP) mutant complex is much lower than that in the wild type or in their respective single cysteine mutant complexes, indicating that formation of an intersubunit disulfide bond between cytochrome b and ISP arrests the head domain of ISP in the "fixed state" position, which is too far for electron transfer to heme c(1).

Amino Acid Substitution↗
PubMed2000

Molecular cloning, genomic organization, and mapping of PRKAG2, a heart abundant gamma2 subunit of 5'-AMP-activated protein kinase, to human chromosome 7q36.

5'-AMP-activated protein kinase (AMPK) acts as a major regulator of cellular ATP levels and protects cells against stresses that cause ATP depletion. AMPK is a protein heterotrimer composed of a catalytic alpha subunit and two regulatory subunits, beta and gamma. In the present study, a homologue of the AMPK gamma1-subunit cDNA with an open reading frame encoding 328 amino acids was identified. The putative protein sequence is about 76% identical to the 331-amino-acid gamma1 subunit and also has four consecutive cystathionine-beta-synthase (CBS) domains, a characteristic structure of AMPK gamma subunits from various species. This cDNA (tentatively termed PRKAG2-b) is identical to a recently reported cDNA (tentatively termed PRKAG2-a) of human AMPK gamma subunits except in their 5'-end regions, suggesting that these two cDNAs are two different transcripts of the same gene. To determine the expression pattern of the gene, two probes, one from the 3'-UTR of PRKAG2-b and the other from the 5'- unique region of PRKAG2-a, were used to hybridize MTN membranes. Three transcripts (3.8, 3.0, and 2.4 kb) were observed when the first probe was used, whereas only 3.8- and 3.0-kb transcripts were seen when the second probe was used. Thus, the PRKAG2-b corresponded to the 2.4-kb transcript, which is ubiquitously expressed except in liver and thymus. The highest level was detected in heart, while abundant expression also existed in placenta and testis. The expression pattern of PRKAG2-b is completely different from those of PRKAG2-a and PRKAG1, whose expression patterns were also determined in the current study. The PRKAG2 gene was located to human chromosome 7q36 between markers D7S2439 and D7S2462 by radiation hybrid mapping. The genomic organization of PRKAG2-b was identified by comparing its cDNA sequence with two genomic sequences AC006358 and AC006966, which showed that PRKAG2-b spanned an approximately 80-kb region and was composed of 12 exons.

AMP-Activated Protein Kinases↗
PubMed2000

Cloning and characterization of human VPS35 and mouse Vps35 and mapping of VPS35 to human chromosome 16q13-q21.

Maintenance of different organelles in eukaryotic cells depends on sorting proteins, which ensure the proper delivery of organelle-specific proteins. The studies on yeast (Saccharomyces cerevisiae) VPS35, a hydrophilic membrane protein having a direct role in the retrieval of cargo proteins, suggest a mechanism underlying a possible lysosomal protein-sorting pathway in mammalian cells. Here, we report the isolation of human and mouse VPS35 cDNAs, which are 3208 and 3186 bp in length, respectively. The deduced proteins of the two cDNAs, which are both composed of 796 amino acids and share 99% identity, show homology to yeast VPS35 and other VPS35 homologues of various sources ranging from Schizosaccharomyces pombe to Drosophila melanogaster (31-56% identity and 49-71% similarity), especially in their amino- and carboxyl-termini. The conservation of VPS35 suggests that the function of this class of protein is important. The results of Northern hybridization of human VPS35 in 16 tissues showed that one transcript of 3.6 kb was highly expressed in brain, heart, testis, ovary, small intestine, spleen, skeletal muscle, and placenta and expressed at moderate or low levels in other tissues. Another transcript of 3.0 kb was also expressed with proportionally lower levels than the 3.6-kb transcript in all the tissues except that the 3.0-kb transcript was not detected in brain. Mouse Vps35 was widely expressed as a 3.4-kb transcript. In addition, human VPS35 was assigned to human chromosome 16q13-q21 by radiation hybrid mapping.

Amino Acid Sequence↗
PubMed2000

Accumulation of dietary cholesterol in sitosterolemia caused by mutations in adjacent ABC transporters.

In healthy individuals, acute changes in cholesterol intake produce modest changes in plasma cholesterol levels. A striking exception occurs in sitosterolemia, an autosomal recessive disorder characterized by increased intestinal absorption and decreased biliary excretion of dietary sterols, hypercholesterolemia, and premature coronary atherosclerosis. We identified seven different mutations in two adjacent, oppositely oriented genes that encode new members of the adenosine triphosphate (ATP)-binding cassette (ABC) transporter family (six mutations in ABCG8 and one in ABCG5) in nine patients with sitosterolemia. The two genes are expressed at highest levels in liver and intestine and, in mice, cholesterol feeding up-regulates expressions of both genes. These data suggest that ABCG5 and ABCG8 normally cooperate to limit intestinal absorption and to promote biliary excretion of sterols, and that mutated forms of these transporters predispose to sterol accumulation and atherosclerosis.

ATP Binding Cassette Transporter, Subfamily G, Mem↗