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Yan Zheng

Publications and source records attributed to Yan Zheng.

At least 37 records · Page 2Linked to original sources
PubMed2005

[Location and relative quantity of coumarins in the stem of Dendrobium thyrsiflorum].

AIM: To determine the location and relative quantity of coumarins in the stem of Dendrobium thyrsiflorum Rchb. f. , and to provide a scientific basis for evaluating and utilizing the famous medicinal plant. METHODS: The stems of one, two and three years old, separately, were collected in February. Location and relative quantity of coumarins in the top, middle and basal parts of each stem sample were determined by using laser scanning confocal microscopy (LSCM). ANOVA and Tukey's test were employed in the statistical analysis. RESULTS: The coumarins located mainly in vascular bundles, especially on the walls of the outer fiber cells. There was significant difference or great significant difference exist in every part of the stem from different ages. The values of significant difference were as follows: basal part P = 0.004 (< 0.01); middle part P = 0.009 (< 0.01); top part P = 0.036( < 0.05). CONCLUSION: Two years old stem could be the best choice when collecting Dendrobium thyrsiflorum in Feburary.

Coumarins↗
PubMed2005

[Isolation and structure identification of the main photolysis product in vitamin K1].

OBJECTIVE: To isolate and identify an unknown photolysis product in Vitamin K1. METHODS: A column chromatography method was used to prepare the impurity, and spectrometric analyses of ultraviolet spectrum, infrared spectrum, mass spectrum and nuclear magnetic resonance spectrum were carried out to identify its structure. RESULTS: Its structure is 2-methyl-3-(3-hydroxy-3, 7, 11, 15-tetramethyl-1-hexadecenyl)-1, 4-naphthoquinone. CONCLUSION: The structure of the photolysis product has been identified.

Molecular Structure↗
PubMed2004

Effects of ghrelin on the proliferation and secretion of splenic T lymphocytes in mice.

Ghrelin, a novel gut--brain peptide predominantly produced by the stomach, displays strong growth hormone (GH)-releasing activity mediated by the hypothalamus-pituitary GH secretagogue receptor (GHS-R). Recently, the ghrelin receptor has also been detected in peripheral systems including immune tissues, suggesting that ghrelin may play an important role in the regulation of immune function. In this paper, we assessed the presence and function of the ghrelin receptor in murine splenic T cells. The enriched T cells express the mRNA of ghrelin and ghrelin receptor mRNA, and there is a significantly positive correlation between them. Moreover, we showed that ghrelin dose-dependently inhibits proliferation of splenic T cells when they are costimulated by anti-CD3. In addition, ghrelin suppressed Th(1) (IL-2 and IFN-gamma) and Th(2) (IL-4 and IL-10) cytokines mRNA expression. These results demonstrate the presence of the ghrelin receptor in murine spleen T lymphocytes and a functional role of ghrelin as a modulator of lymphocyte function. This function of ghrelin may have some relevance to the pathophysiology of immunologic alterations related to metabolism.

Animals↗
PubMed2004

Flt3-ligand, IL-4, GM-CSF, and adherence-mediated isolation of murine lung dendritic cells: assessment of isolation technique on phenotype and function.

Lung dendritic cells (DCs) are difficult to study due to their limited quantities and the complexities required for isolation. Although many procedures have been used to overcome this challenge, the effects of isolation techniques on lung DCs have not been reported. The current study shows that freshly isolated DCs (CD11c+) have limited ability to induce proliferation in allogeneic T cells, and are immature as indicated by low cell surface expression of costimulatory molecules compared with liver or splenic DCs. DCs isolated after overnight culture or from mice treated with Flt3L are phenotypically mature and potent stimulators of allogeneic T cells. DCs could not be propagated from lung mononuclear cells in response to IL-4 and GM-CSF. Contrary to data reported for nonpulmonary DCs, expression of CCR6 was decreased on mature lung DCs, and only a subset of mature DCs expressed higher levels of CCR7. Absence of CD8alpha expression indicates that freshly isolated DCs are myeloid-type, whereas mature DCs induced by overnight culture are both "lymphoid" (CD8alpha+) and "myeloid" (CD8alpha-). DCs from mice genetically deficient in CD8alpha expression were strong simulators of allogeneic T cells which was consistent with data showing that CD8alpha- DCs from CD8alpha-sufficient mice are better APCs compared with CD8alpha+ DCs from the same mice. These data show that freshly isolated lung DCs are phenotypically and functionally distinct, and that the isolation technique alters the biology of these cells. Therefore, lung DC phenotype and function must be interpreted relative to the technique used for isolation.

Animals↗
PubMed2004

The novel cyclophilin binding compound, sanglifehrin A, disassociates G1 cell cycle arrest from tolerance induction.

T cell anergy has been demonstrated to play a role in maintaining peripheral tolerance to self Ags as well as a means by which tumors can evade immune destruction. Although the precise pathways involved in anergy induction have yet to be elucidated, it has been linked to TCR engagement in the setting of cell cycle arrest. Indeed, rapamycin, which inhibits T cell proliferation in G(1), has the ability to promote tolerance even in the presence of costimulation. To better define the role of the cell cycle in regulating anergy induction, we used the novel cyclophilin-binding ligand, sanglifehrin A (SFA). We demonstrate that SFA can inhibit TCR-induced cytokine and chemokine production without preventing TCR-induced anergy. Our data also indicate that despite its ability to induce G(1) arrest, SFA does not induce anergy in the presence of costimulation. Furthermore, although SFA blocks proliferation to exogenous IL-2, it does not prevent IL-2-induced reversal of anergy. When we examined the phosphorylation of 4EBP-1, a downstream substrate of the mammalian target of rapamycin, we found that rapamycin, but not SFA, inhibited the mammalian target of rapamycin activity. Based on these data, we propose that the decision as to whether TCR engagement will lead to productive activation or tolerance is dictated by a rapamycin -inhibitable pathway, independent of the G(1)-->S phase cell cycle progression.

Animals↗
PubMed2004

Half-life and DNA strand scission products of 2-deoxyribonolactone oxidative DNA damage lesions.

Reactive oxygen species lead to oxidative damage of the nucleobase and sugar components of nucleotides in double-stranded DNA. The 2-deoxyribonolactone (or oxidized abasic site) lesion results from oxidation of the C-1' position of DNA nucleotides and has been implicated in DNA strand scission, mutagenesis, and covalent cross-linking to DNA binding proteins. We previously described a strategy for the synthesis of DNA-containing deoxyribonolactone lesions. We now report an improved method for the site specific photochemical generation of deoxyribonolactone sites within DNA oligonucleotides and utilize these synthetic oligonucleotides to characterize the products and rates of DNA strand scission at the lactone lesion under simulated physiological conditions. A C-1' nitroveratryl cyanohydrin phosphoramidite analogue was synthesized and used for the preparation of DNA containing a photochemically "caged" lactone precursor. Irradiation at 350 nm quantitatively converted the caged analogue into the deoxyribonolactone lesion. The methodology was validated by RP-HPLC and MALDI-TOF mass spectrometry. Incubation of deoxyribonolactone-containing DNA under simulated physiological conditions gave rise to DNA fragmentation by two consecutive elimination reactions. The DNA-containing products resulting from DNA cleavage at the deoxyribonolactone site were isolated by PAGE and unambiguously characterized by MALDI-TOF MS and chemical fingerprinting assays. The rate of DNA strand scission at the deoxyribonolactone site was measured in single- and double-stranded DNA under simulated physiological conditions: DNA cleavage occurred with a half-life of approximately 20 h in single-stranded DNA and 32-54 h in duplex DNA, dependent on the identity of the deoxynucleotide paired opposite the lesion site. The initial alpha,beta-elimination reaction was shown to be the rate-determining step for the formation of methylene furanone and phosphorylated DNA products. These investigations demonstrated that the deoxyribonolactone site represents a labile lesion under simulated physiological conditions and forms the basis for further studies of the biological effects of this oxidative DNA damage lesion.

Base Sequence↗
PubMed2004

The apparent absorptions of isoflavone glucosides and aglucons are similar in women and are increased by rapid gut transit time and low fecal isoflavone degradation.

We hypothesized that there would be no difference in apparent absorption, as assessed by urinary excretion, between isoflavone sources rich in glucosides or aglucons and that subjects with rapid gut transit time (GTT) and low fecal isoflavone degradation phenotype would absorb more isoflavones. Women (n = 13) with a fecal daidzein degradation rate constant, D(k) > 0.30 h(-1) (high degraders) and GTT of 106 +/- 11 h and women (n = 12) with D(k) < 0.20 h(-1) (low degraders) and GTT of 71 +/- 12 h were randomly assigned to 3 treatments: soygerm (1.1 micromol/kg body weight, n = 5 high degraders, 4 low degraders), fermented soygerm (3.3 micromol/kg, n = 4 high and 4 low degraders) or Novasoy isoflavone extract (1.5 micromol/kg, n = 4 high and 4 low degraders) for 7 d. By HPLC analysis, 24-h urinary excretion of soygerm was greater than Novasoy (51 +/- 6 vs. 26 +/- 6% of ingested dose, P < 0.05). Women of the low daidzein degradation phenotype had greater urinary isoflavone excretion than did women of the high daidzein degradation phenotype (51.6 +/- 4.8 vs. 33.8 +/- 4.7%, P < 0.05, mean of d1 and 7). The plasma total isoflavone level (estimated as a percentage of the ingested amount, mean of d 1 and 7) differed between women who consumed fermented soygerm and soygerm 3 h after feeding (1.8 +/- 0.3 vs. 0.5 +/- 0.3%, P < 0.05). Urinary excretions of aglucons and glucosides did not differ. The study confirmed that rapid GTT and low fecal isoflavone degradation rate increased the apparent absorption of isoflavones.

Administration, Oral↗
PubMed2004

[Cholesterol granuloma media: 8 cases report].

OBJECTIVE: To investigate the etiology, pathogenesis diagnosis and therapy of cholesterol granuloma media. METHOD: Eight cases (9 ears) of middle ear cholesterol granuloma were retrospectively reviewed. Nine ears all have a speciality of conductive deafness with a light to middle level, blue eardrum and tympanogram all showing B type (except one case of eardrum perforation in the tension part). Seven cases (8 ears) were cured by tympanic cavity exploration opening epitympanum, tympanic antrum, mastoid cells and thoroughly eliminating granulation tissue. Grommet insertion and modified radical mastoidectomy were performed on 5 cases and 2 cases, respectively. The other one case was only carried out with eardrum puncture. RESULT: Seven cases (8 ears) after operation were followed up for six monthes to six years. Six cases (7 ears) were cured out without recurring; one case (1 ear) recurred. One case was not followed up. CONCLUSION: Otoblennorrhea of blood without obvious reason and blue eardrum should be coupled with CT to enhance the diagnosis rate before operation. CG should be treated by operation to clean disease location, air and drainage tympanicus cavity and mastoid.

Adolescent↗
PubMed2003

Synthesis, characteristics and luminescence properties of oligo(phenylenevinylene) dimers with a biphenyl linkage center.

Building a new structual oligo(phenylenevinylene) by linking trimeric phenylenvinylene (TPV) through the phenylphenyl bond of a central phenylene ring was reported. The resultant TPV dimers exhibit weak intermolecular interactions and intense blue photoluminescence in the solid state as well as high phase transition temperatures up to 250 degrees C. Organic light-emitting devices (OLEDs) based on these materials display blue emission with low turn-on voltage (about 3 V), maximum luminance approaching 2000 cd m(-2) and efficiency up to 1.6 cd A(-1).

Journal Article↗
PubMed2003

CDllc+ cells modulate pulmonary immune responses by production of indoleamine 2,3-dioxygenase.

Interactions between antigen-presenting cells and T cells can result in T cell activation or suppression. With the use of RNA analysis, high-performance liquid chromatography, mixed leukocyte reactions (MLRs), and animal models, the current study reports that lung interstitial antigen-presenting cells (iAPCs, CDllc+) suppress T cell responses in vitro and in vivo by production of indoleamine 2,3-dioxygenase (IDO), an enzyme that catabolizes tryptophan to its byproduct, kynurenine. IDO mRNA expression was unique to lung iAPCs, as cells similarly isolated from the liver and spleen did not express IDO constitutively, or in response to interferon-gamma. Lung iAPCs suppressed proliferation of allogeneic T cells, correlating with increased kynurenine levels; and blockade of IDO activity with 1-methyl-DL-tryptohan (1-MT) or addition of exogenous tryptophan recovered T cell proliferation in MLRs. In contrast, liver and splenic iAPCs were potent stimulators of T cells in MLRs, and IDO inhibition had no effect on T cell responses. In vivo studies showed that systemic blockade of IDO resulted in spontaneous proliferation in lung T cells and pulmonary inflammation. Finally, overexpressing IDO in lung transplants abrogated acute allograft rejection, a T cell-mediated disease. Collectively these data show that lung iAPCs contribute to local regulation of cellular immune responses by production of IDO.

Animals↗
PubMed2003

Differential expression of Smad7 transcripts identifies the CD4+CD45RChigh regulatory T cells that mediate type V collagen-induced tolerance to lung allografts.

Regulatory T cells (Tregs) induced by oral tolerance may suppress immunity by production of TGF-beta that could also enhance Treg activity. However, all cells that are phenotypically Tregs in rats (CD4(+)CD45RC(high)-RC(high)) may not have regulatory function. Because Smad7 expression in T cells is associated with inflammation and autoimmunity, then lack of Smad7 may identify those cells that function as Tregs. We reported that feeding type V collagen (col(V)) to WKY rats (RT1(l)) induces oral tolerance to lung allografts (F344-RT1(lvl)) by T cells that produce TGF-beta. The purpose of the current study was to identify the Tregs that mediate col(V)-induced tolerance, and determine Smad7 expression in these cells. RC(high) cells from tolerant rats were unresponsive to allogeneic stimulation and abrogated rejection after adoptive transfer. In contrast, CD4(+)CD45RC(low) (RC(low)) cells from tolerant rats and RC(high) or RC(low) cells from normal rats or untreated allograft recipients proliferated vigorously in response to donor Ags, and did not suppress rejection after adoptive transfer. TGF-beta enhanced proliferation in response to col(V) presented to tolerant RC(high), but not other cells. In contrast to other cells, only RC(high) cells from tolerant rats did not express Smad7. Collectively, these data show that the Tregs that mediate col(V)-induced tolerance to lung allografts do not express SMAD7 and, therefore, are permissive to TGF-beta-mediated signaling.

Adoptive Transfer↗
PubMed2003

Inhibitory signal override increases susceptibility to mercury-induced autoimmunity.

After exposure to subtoxic doses of heavy metals such as mercury, H-2(s) mice develop an autoimmune syndrome consisting of the rapid production of IgG autoantibodies that are highly specific for nucleolar autoantigens and a polyclonal increase in serum IgG1 and IgE. In this study, we explore the role of two inhibitory immunoreceptors, CTLA-4 and FcgammaRIIB, in the regulation of mercury-induced autoimmunity. In susceptible mice treated with mercuric chloride (HgCl(2)), administration of a blocking anti-CTLA-4 Ab resulted in a further increase in anti-nucleolar autoantibodies and in total serum IgG1 levels. Furthermore, in some DBA/2 mice, which are normally resistant to heavy metal-induced autoimmunity, anti-CTLA-4 treatment leads to the production of anti-nucleolar Abs, thereby overcoming the genetic restriction of the disease. In mice deficient for the FcgammaRIIB, HgCl(2) administration did not trigger autoantibody production, but resulted in an increase in IgE serum levels. Taken together, these results indicate that different inhibitory mechanisms regulate various manifestations of this autoimmune syndrome.

Animals↗
PubMed2003

Rapid gut transit time and slow fecal isoflavone disappearance phenotype are associated with greater genistein bioavailability in women.

The bioavailability of soybean isoflavones varies widely among individuals due to many factors, including activities of gut microflora. To characterize factors that affect fecal isoflavone disappearance phenotype and isoflavone bioavailability in women, 35 Asian and 33 Caucasian women, 18-43 y of age, provided fecal samples for anaerobic incubation with isoflavones in vitro at two times 5 mo apart (Phases I and II). Diet, physical activity and health history were investigated at these times. A single dose of soymilk powder [1.2 mg (4.57 micromol) total isoflavone/kg body] was given to all subjects with breakfast in phase II. Daidzein and genistein from fecal incubations, urine and fecal samples were measured by reverse-phase HPLC. Three significantly different daidzein and two genistein disappearance phenotypes were identified from fecal isoflavone incubations. More Asians than Caucasians were identified within the high daidzein disappearance phenotype. Caucasians and Asians differed significantly in daily intake of red meat (0.3 +/- 0.1 vs. 1.0 +/- 0.1 servings/d), dairy foods (2.9 +/- 0.2 vs. 1.2 +/- 0.2 servings/d) and insoluble dietary fiber (3.6 +/- 0.3 vs. 1.4 +/- 0.3 g). BMI, maximal oxygen uptake (VO(2 max)) and physical activity level were significantly greater in Caucasians than in Asians. Asian subjects of the low genistein disappearance phenotype had more rapid gut transit time (GTT) and greater isoflavone bioavailability as reflected in urinary genistein excretion than did Asians of the high genistein disappearance phenotype (GTT, 40 +/- 8 vs. 63 +/- 5 h; 11.0 +/- 2.7 vs. 4.0 +/- 1.7% of ingested genistein excreted in urine). Caucasians of both genistein disappearance phenotypes had longer GTT than did Asian subjects (84 +/- 5 vs. 56 +/- 6 h) and resembled Asians of the high genistein disappearance phenotype in genistein bioavailability. Relatively rapid GTT coupled with a low fecal isoflavone disappearance phenotype as occurred in Asian but not Caucasian subjects produced greater genistein bioavailability, as reflected in urinary genistein excretion.

Adolescent↗
PubMed2003

Alteration and significance of heparin-binding epidermal-growth-factor-like growth factor in psoriatic epidermis.

BACKGROUND: Heparin-binding epidermal-growth-factor-like growth factor (HB-EGF) has proved to be a mitogen of keratinocytes, which may be involved in the pathogenesis of inflammatory diseases, but its mechanism in psoriasis remains unknown. OBJECTIVE: To investigate the alteration of HB-EGF in the epidermis of active psoriasis vulgaris. METHODS: The expression of HB-EGF in normal skin tissues, uninvolved tissues and psoriatic lesions was detected by in situ hybridization and immunohistochemistry. RESULTS: HB-EGF mRNA and protein were located in the basal layer of normal epidermis (10/10, 100.00%), with nearly no expression in the suprabasal layers (1/10, 10.00%); the expression of HB-EGF was located not only in the basal layer (21/21, 100.00%), but was also seen as focal overexpression in the suprabasal layers of uninvolved epidermis (20/21, 95.24%) and the marginal part of psoriatic lesions (18/21, 85.71%), while nearly no expression of HB-EGF was found in the central part of psoriatic lesions (1/21, 4.76%). CONCLUSION: HB-EGF may play an important role in the early pathogenesis of psoriasis.

Adolescent↗
PubMed2003

[Treatment of cleft palate with secretory otitis media].

OBJECTIVE: To gain a clear idea of the function of middle ear and hearing in cleft palate with secretory otitis media after pressure equalization tube insertion. METHODS: 53 cleft palate cases with secretory otitis media including 62 ears were divided into treatment and control groups. They were examined by tympanogram and hearing threshold. RESULTS: Hearing threshold in treatment group after PE tube insertion respectively was 23.3 dB and 23.4 dB in the near future and at a specified future date. It was normal. But there were still 64% tympanogram B and C. CONCLUSIONS: PE tube insertion could solve hearing problem, but could not improve the function of middle ear.

Child↗