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Na Li

Publications and source records attributed to Na Li.

At least 91 records · Page 5Linked to original sources
PubMed2005

Three new triterpenes from Nerium oleander and biological activity of the isolated compounds.

New ursane-type triterpene 1, oleanane-type triterpene 2, and dammarane-type triterpene 15 were isolated from the leaves of Nerium oleander together with 12 known triterpenes, 3beta-hydroxy-12-ursen-28-oic acid (ursolic acid, 3), 3beta,27-dihydroxy-12-ursen-28-oic acid (4), 3beta,13beta-dihydroxyurs-11-en-28-oic acid (5), 3beta-hydroxyurs-12-en-28-aldehyde (6), 28-norurs-12-en-3beta-ol (7), urs-12-en-3beta-ol (8), urs-12-ene-3beta,28-diol (9), 3beta-hydroxy-12-oleanen-28-oic acid (oleanolic acid, 10), 3beta,27-dihydroxy-12-oleanen-28-oic acid (11), 3beta-hydroxy-20(29)-lupen-28-oic acid (betulinic acid, 12), 20(29)-lupene-3beta,28-diol (betulin, 13), and (20S,24R)-epoxydammarane-3beta,25-diol (14). On the basis of their spectroscopic data, the structures of the new compounds 1, 2, and 15 were established as 3beta,20alpha-dihydroxyurs-21-en-28-oic acid, 3beta,12alpha-dihydroxyoleanan-28,13beta-olide, and (20S,24S)-epoxydammarane-3beta,25-diol, respectively. The anti-inflammatory activity of the seven isolated compounds and methyl esters of ursolic acid and oleanoic acid in vitro was examined on the basis of inhibitory activity against the induction of the intercellular adhesion molecule-1 (ICAM-1). The anticancer activity of the 14 isolated compounds, including 1, 2, 15, and methyl esters of ursolic acid and oleanolic acid in vitro was examined on the basis of the cell growth inhibitory activities toward three kinds of human cell lines.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2005

Bioactive tetrahydrofuran lignans from Peperomia dindygulensis.

Five new tetrahydrofuran lignans (1-5), accompanied by four known compounds, were isolated from the ethyl acetate extract of Peperomia dindygulensis. Structures were elucidated mainly using 1D NMR, 2D NMR, and mass spectroscopic studies. The relative configurations of 1-5 were determined by NOE correlations. Several of the compounds showed weak growth inhibitory activity against three cell lines (WI-38, VA-13, and HepG2). Compound 5 exhibited stronger MDR (multidrug resistance) reversal activity than verapamil at 2.5 microg/mL in a cellular calcein accumulation assay. Compounds 4 and 5 showed weak inhibitory activity against induction of the intercellular adhesion molecule-1 (ICAM-1) in anti-inflammatory activity experiments.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2005

Overexpression of Bax sensitizes prostate cancer cells to TGF-beta induced apoptosis.

NRP-154 is a tumorigenic epithelial cell line derived from the preneoplastic dorsal-lateral prostate of rats. These cells are exquisitely sensitive to TGF-beta induced apoptosis. In contrast, we find that NRP-154 cells can sustain overexpression of exogenous Bax protein, which is different from non-tumor cells where Bax functions as a ubiquitous stimulator of apoptosis. NRP-154 cells stably overexpressing Bax show increased sensitivity to TGF-beta induced apoptosis. The degree of TGF-beta induced apoptosis displays high correlation with cleavage of Bax at the amino-terminus. Our data indicate that prostate cancer cells can host high levels of latent Bax which can be activated through post-translational modification.

Animals↗
PubMed2005

DNAzymes targeting the icl gene inhibit ICL expression and decrease Mycobacterium tuberculosis survival in macrophages.

Latent infection with Mycobacterium tuberculosis presents a big obstacle for tuberculosis therapy. In this study, we investigated the effects of sequence-specific DNAzymes targeting the mRNA of isocitrate lyase (ICL), an enzyme playing a pivotal role in the metabolism of M. tuberculosis in the latent state, on the expression of ICL and survival of M. tuberculosis. In vitro studies showed that four of five designed DNAzymes, DZ1, DZ3, DZ4, and DZ5 could cleave icl mRNA efficiently and specifically. Treatment of virulent M. tuberculosis with 5microM DZ4 plus a subinhibitory concentration of isoniazid (INH) decreased ICL expression and the survival of M. tuberculosis in macrophages but had no obvious influence on the growth of M. tuberculosis in vitro. This study demonstrates that using INH to soften the cell wall of M. tuberculosis and help the entry of biomolecules is an efficient method of improving the uptake of DNAzymes. Silencing the icl gene by DNAzyme is a promising method to combat latent infection of tuberculosis.

Antitubercular Agents↗
PubMed2005

Osteopetrotic mouse stroma with thrombopoietin, c-kit ligand, and flk-2 ligand supports long-term mobilized CD34+ hematopoiesis in vitro.

OP-9 cells are stromal cells derived from macrophage colony-stimulating factor (M-CSF)-deficient osteopetrotic mice. To evaluate the OP-9 capability to sustain long-term hematopoiesis, we reported the expansion of granulocyte colony-stimulating factor (G-CSF)-mobilized human peripheral blood (PB) CD34(+) cells in co-culture with murine OP-9 and MS-5 stromal cells, either transfected with various combinations of adenovectors (Ad) expressing c-kit ligand (KL) (either soluble or transmembrane form), thrombopoietin (TPO), flt-3/flk2 ligand (FL), and granulocyte-macrophage (GM)-CSF or with weekly addition of these cytokines. Expression of TPO as well as association of TPO, FL, and KL increased progenitor cell and week-6 cobblestone area forming cell (CAFC) production in all stromal co-cultures. Similar progenitor expansion was obtained by weekly addition of soluble cytokine. Five weeks of co-culture with OP9 and TPO, FL + KL resulted in the greatest expansion of progenitor cells and week-6 CAFC as measured by secondary assay on MS-5. In contrast to MS-5 and TPO or TPO + FL + KL cultures where hematopoiesis declined by week 4, progenitor as well as week-6 CAFC expansion continued for over 3 months in TPO + FL + KL OP9 cocultures. This was associated with decrease of CD14(+) macrophage production. The addition of human macrophage (M)-CSF or CD14(+) cells to the co-culture decrease progenitor and stem cell expansion; however, murine M-CSF to OP-9 co-cultures did not decrease progenitor expansion. High levels of stromal-derived factor-1 (SDF-1) production by MS-5 and low or absent production by OP-9 may account for stem cell adhesion and CAFC formation in the former cultures and the predominance of stem and progenitor cells in the nonadherent fraction in the latter cultures.

Adenoviridae↗
PubMed2005

Mice deficient in corticotropin-releasing factor receptor type 2 exhibit normal ethanol-associated behaviors.

BACKGROUND: Stress is believed to influence alcohol use and relapse in alcoholics. Animal studies suggest an interaction between corticotropin-releasing factor (CRF) and its receptors and the behavioral effects and consumption of alcohol. The objective of these studies was to examine the effect of corticotropin-releasing factor receptor type 2 (CRF2) on ethanol consumption, conditioned taste aversion, sedation, and hypothermia. METHODS: CRF2-null mutant or knock-out (KO), and wild-type (WT) mice were used to assess consumption of increasing concentrations of ethanol in a two-bottle, 24-hr test and during daily limited-access sessions. Ethanol-induced conditioned taste aversion (CTA), loss of righting reflex (LORR), hypothermia, and ethanol metabolism kinetics were also examined in the CRF2 KO and WT mice. RESULTS: CRF2 KO mice did not differ from WT mice in sensitivity to ethanol-induced CTA, LORR, hypothermia, or ethanol metabolism kinetics. There was no genotypic difference in ethanol intake or preference in the 24-hr, two-bottle choice procedure, and only modestly increased [corrected] consumption of the 7.5 and 10% ethanol solutions in KO versus WT mice in the limited-access procedure. CONCLUSIONS: CRF2 deficiency had little effect on several ethanol-associated behaviors in CRF2-null mutant compared with WT mice, suggesting that this receptor does not have a primary role in modulating these behaviors. Evidence of a role for this receptor in neural circuits subserving stress-coping behaviors suggest that future studies should focus on the role of endogenous CRF2 in ethanol-associated behaviors in mice that are stressed or withdrawing from dependence on ethanol.

Animals↗
PubMed2005

Oct-1 counteracts autoinhibition of Runx2 DNA binding to form a novel Runx2/Oct-1 complex on the promoter of the mammary gland-specific gene beta-casein.

The transcription factor Runx2 is essential for the expression of a number of bone-specific genes and is primarily considered a master regulator of bone development. Runx2 is also expressed in mammary epithelial cells, but its role in the mammary gland has not been established. Here we show that Runx2 forms a novel complex with the ubiquitous transcription factor Oct-1 to regulate the expression of the mammary gland-specific gene beta-casein. The Runx2/Oct-1 complex forms on a Runx/octamer element which is highly conserved in casein promoters. Chromatin immunoprecipitation, RNA interference, promoter mutagenesis, and transient expression analyses were used to demonstrate that the Runx2/Oct-1 complex contributes to the transcriptional regulation of the beta-casein gene. Analysis of the complex revealed autoinhibitory domains for DNA binding in both the N-terminal and the C-terminal regions of Runx2. Oct-1 stimulates the recruitment of Runx2 to the beta-casein promoter by interacting with the C-terminal region of Runx2, suggesting that Oct-1 stimulates Runx2 recruitment by relieving the autoinhibition of Runx2 DNA binding. These findings demonstrate that Runx2 collaborates with Oct-1 and contributes to the expression of a mammary gland-specific gene.

Animals↗
PubMed2005

Analgesic and anti-inflammatory activities of total extract and individual fractions of Chinese medicinal ants Polyrhachis lamellidens.

The ethanol extract of Chinese medicinal ants Polyrhachis lamelliden was evaluated for its analgesic and anti-inflammatory activities in mice. It was shown that the extract significantly inhibited acetic acid-induced writhing response and increased hot-plate pain threshold of mice at doses of 1.5 and 3.0 g crude drug/kg. Meanwhile, the extract significantly inhibited the increase in vascular permeability induced by acetic acid and in ear edema induced by xylene in mice. However, it had no obvious effect on leukocyte migration induced by carboxymethylcellulose sodium (CMC-Na). The ethanol extract suspended in water was partitioned with diethyl ether, ethyl acetate and n-butanol successively to yield four fractions including water fraction. Among these fractions, diethyl ether and ethyl acetate fractions were found to increase hot-plate pain threshold and to inhibit acetic acid-induced writhing response in mice. Water fractions markedly inhibited acetic acid-induced writhing response and reduced the dye leakage to the peritoneal cavity induced by acetic acid and ear edema induced by xylene. These results suggest that P. lamellidens presents remarkable analgesic and anti-inflammatory activity, which supported the traditional use of the medicinal ants in the treatment of various diseases associated with inflammation. The diethyl ether fraction has greater contribution to the overall analgesic activity, whereas the water fraction showed the greatest anti-inflammatory and peripheral analgesic activities.

Analgesics↗
PubMed2005

[Speciation analysis of mercury in traditional Chinese medicine by vapor-generation atomic fluorescence spectrometry].

A sensitive method has been proposed for the determination of inorganic mercury and total organic mercury in traditional Chinese medicine (Wanshi Niuhuang Qingxin) by vapor-generation atomic fluorescence spectrometry. The experimental conditions that influence the atomic fluorescence signal intensity of Hg and the oxidization of organic mercury were investigated and optimized. Thiourea citric acid was selected as a sensitization agent, which greatly enhanced atomic fluorescence signal intensity of mercury. The influence of foreign ions and their elimination were studied. The detection limit of the method for Hg was 7.6 ng x L(-1) and the relative standard deviation was 1.56%-3.28% for Hg. The proposed method was successfully applied to the determination of mercury speciation in real samples with a recovery range of 90.3%-110.3%.

Citric Acid↗
PubMed2005

[Detection of small molecules based on surface plasmon (correction of plasman) resonance technology].

OBJECTIVE: To develop a detective method applied in online assaying of astronauts' humours using the portable online bio-molecules analyzer (POBA) based on surface plasmon resonance biosensor. METHOD: An assay format was developed based on the detection of 2, 4-Dinitrophenyl-hydrazine. The bio-molecule slide was made by DNP-BSA. Range of detection and standard curve were obtained using inhibition assay. Reliability and specificity of the assay were also tested. RESULT: 1) The linear range of the assay was 7.8 ng/ml-2 micrograms/ml with lower detection limit of 2.5 ng/ml; 2) Preparation of the bio-molecule slide and regeneration of the biosensor ensured detections for many samples. CONCLUSION: This assay method can be used to detect small molecules sensitively, rapidly and easily. It can be repeated with good reliability, and has a good application in space medicine.

Aerospace Medicine↗
PubMed2005

[Genome constitution of Agropyron elongatum 4x by biochemical and SSR markers].

We analyzed the electrophoritic patterns of 16 kinds of isozyme and three kinds of storage protein in Agropyron elongatum 2x and Ag. elongatum 4x by isoelectric focusing (IEF) and SDS-PAGE, respectively. The results showed three types of electrophoritic patterns. In the first type, the zymogram phenotypes are identical between Ag. elongatum 2x and Ag. elongatum 4x. Two kinds of isozyme belong to this type, which accounts for 10.5% of all the biochemical markers analyzed. In the second type, Ag. elongatum 4x showed a phenotype which is made up of combinations of the all of Ag. elongatum 2x bands and the specific bands. Ten kinds of isozyme and three kinds of storage protein fall into this class, which is the most part and accounts for 63.2% of all the markers analyzed. In the third type, Ag. elongatum 2x and Ag. elongatum 4x showed some identical bands and their own specific bands. Five kinds of isozyme were classified to this group,which accounts for 26.3% of all the markers analyzed. The results above suggested that Ag. elongatum 4x is a allotetraploid composed of one genome originated from Ag. elongatum 2x and another unknown genome which is apparently distinct from the St, J and N genomes of relative species. Otherwise, SSR primers were used to analyze the relation of Ag. elongatum 2x and Ag. elongatum 4x. The amplification results of most primers showed that Ag. elongatum 2x and Ag. elongatum 4x have some identical bands and Ag. elongatum 4x have some specific bands. This result validated the conclusion from biochemical marker analyses that Ag. elongatum 4x is a allotetraploid.

Agropyron↗
PubMed2005

[Inhibition of postharvest decay and induction of defensive enzymes by pure oxygen in Chinese bayberry fruit].

Chinese bayberry fruits were stored in air (control) or pure oxygen atmosphere for up to 12 days at 5 degrees C to investigate the effects of high oxygen on decay control and its relation to the induction of defensive enzyme activities. The results showed that exposure of Chinese bayberry to pure oxygen significantly prevented fruit decay. At the end of the storage period, the decay index of fruits exposed to pure oxygen was only 17% while that of control fruits reached 54% (Fig.1). Pure oxygen caused a significant increase in chitinase and beta-1,3-glucanase activities which reached a peak on the 6th day of storage (Fig.2). Phenylalanine ammonium-lyase (Fig.3A) and peroxidase (Fig.4) activities as well as total phenolic content (Fig.3B) increased more quickly and stayed at significantly higher levels in fruits exposed to pure oxygen during storage than the control fruits. These results suggest that the inhibition of postharvest fruit decay by high oxygen was related to the induction of defensive enzyme activities. The induced disease resistance may be involved in the mechanisms by which high oxygen treatment inhibited fruit decay in Chinese bayberry.

Chitinases↗
PubMed2005

[Genetic analysis and mapping of the rice leafy-hull mutant Oslh].

Oslh (lh=leafy hull), in the japonica cultivar 9522 background, a mutant of Oryza sativa L. spp. japonica cv. 9522 identified from an M(2) population, was mutagenized by irradiation with (60)Co gamma-ray. The Oslh mutant plants flowered about 15 days later than the wild-type plants (Fig.1e). The paleas, lemmas and lodicules of the flowers of Oslh mutant were transformed into leaf-like structures (Fig.1b, d). Genetic analysis of the F(2) progeny from a cross between the Oslh mutant and wild-type japonica cv. 9522 revealed that the Oslh mutant arouse from a single recessive nuclear gene mutation of the cv. 9522. To map the Oslh locus, an F(2) population generated by crossing between Oslh (japonica) mutant and Guangluai4 (indica) was analyzed. The Oslh locus was mapped to the long arm of rice chromosome 3, between a SSR marker RM5475 and an InDel marker GY305, 2.9 and 1.5 cM away from these two markers respectively (Fig.4). These results are useful for further cloning and functional analysis of the OsLH gene.

Chromosome Mapping↗
PubMed2005

[Interaction of surface active fluorescence probes and bovine serum albumin].

The binding between two surface-active substituted 3H-indole fluorescence probes, i. e., iodo-dihexadecyl methyl-2-(p-dodecyl amino phenyl)-3, 3-dimethyl-5-carboethoxy-3H-indole ammonium and iodo-dimethyloctadecyl-2-(p-dodecyl amino phenyl)-3,3-dimethyl-5-carboethoxy-3H-indole ammonium, and bovine serum albumin (BSA) in aqueous solution was studied using fluorescence. The binding constant and binding site number of molecule 1 and molecule 2 with BSA were obtained. It was confirmed that electrostatic interaction is the primary driving force for the combination of BSA with molecule 1 or molecule 2. According to the Förster resonance energy transfer theory, the distances between molecule 1, molecule 2 and tryptophan of BSA were calculated to be 2.90 nm and 4.02 nm, respectively.

Algorithms↗
PubMed2005

[Effect of hydroxyethyl starch and Ringer's solution on splanchnic perfusion in dogs with septic shock].

OBJECTIVE: To investigate the effect of 6% hydroxyethyl starch (HES) and Ringer's solution (RS) on splanchnic perfusion in dogs with septic shock. METHODS: Twenty-four mongrel dogs with septic shock induced by lipopolysaccharides (LPS) were randomly divided into two groups: HES group and RS group. Dogs of each group received an intravenous infusion of HES or RS (1 mlxkg(-1)xmin(-1)) for 60 minutes, followed by normal saline for 180 minutes with same infusion speed. Parameters of hemodynamics, oxygen dynamic, and splanchnic perfusion were monitored at 0, 30, 60, 120, 180, 240 minutes after basic measurements (pre-LPS). RESULTS: (1) After LPS infusion, mean arterial pressure (MAP) and cardiac index (CI) lowered significantly (P<0.05). Compared to that of 0 minutes, MAP and CI were elevated by fluid therapy in both groups, but there was no difference between HES and RS group. (2) Compared with pre-LPS, oxygen delivery (DO(2)) was reduced, arterial blood pH lowered and arterial lactate level increased markedly at 0 minutes (P<0.05). DO(2) increased by fluid therapy in both groups, but DO(2) was higher in HES group at the same time points (P<0.05). Compared to 0 minutes, arterial lactate levels were lowered at 180 minutes in both groups. (3) Mesenteric blood flow decreased after LPS infusion in all animals (P<0.05). Mesenteric blood flow increased after HES infusion, at the same time intramucosal pH (pHi) was elevated and Pg-aCO(2) decreased significantly (all P<0.05), but they showed no difference in RS group. At the same time, mesenteric blood flow and pHi was higher in HES group than that in RS group. CONCLUSION: Both HES and RS could improve MAP and DO(2) in dogs with septic shock, but the effect of HES was better than RS on splanchnic perfusion.

Animals↗
PubMed2005

[Establishment and characterization of the lung cancer A549 cell stains with down-regulated expressed HOGG1 genes].

OBJECTIVE: To establish lung cancer A549 cell strains with down-regulated expressed HOGG1 genes and study its biological characteristics. METHODS: The eukaryotic expression vectors with genes of hammerhead ribozyme targeting human 8-oxoguanine DNA glycosylase 1 (HOGG1) mRNA were transfected into A549 cells by liposmes, and then were screened by G418 till stable cell strains were constructed. The positive recombinants were identified by RT-PCR to amplify NEO genes. The efficacy of inhibition was tested by RT-PCR. Furthermore, morphology, survival curves, cell cycle, cloning efficiency grow in the soft agar and the activity of superoxide dismutase (SOD) were investigated. RESULTS: The HOGG1-down-regulated expressed A549 cell strains were obtained after G418 selection and NEO genes identification. The mRNA expression level of HOGG1 genes in the down-regulated expressed cells named A549-R were decreased 61.5% than in the untransfected cells A549 (P < 0.05). There was no significant difference between A549-R cells and A549 cells in morphology, the population doubling time and cell cycle. The numbers of clones in the soft agar of A549-R cells was decreased nearly to 50% than of A549 cells (P < 0.05), but the activity of SOD was increased obviously (P < 0.05). CONCLUSION: The lung cancer A549 cell strains with down-regulated expressed HOGG1 genes by silencing and incision of ribozyme were successfully established. Its biological characteristics have no significant changes in most of indexes.

Adenocarcinoma↗
PubMed2004

ING4 induces G2/M cell cycle arrest and enhances the chemosensitivity to DNA-damage agents in HepG2 cells.

The known members of inhibitor of growth (ING) gene family are considered as candidate tumor suppressor genes. ING4, a novel member of ING family, is recently reported to interact with tumor suppressor p53, p300 (a major component of histone acetyl transferase complexes), and p65(RelA) subunit of NF-kappaB. In this study, we investigated the cellular behaviors of HepG2 cells with exogenous ING4. Interestingly, the overexpression of ING4 negatively regulated the cell growth with significant G2/M arrest of cell cycle, and moreover, enhanced the cell apoptosis triggered by serum starvation in HepG2 cells. Furthermore, the exogenous ING4 could upregulate endogenous p21 and Bax in HepG2 cells, not in p53-deficient Saos-2 cells, suggesting that G2/M arrest induced by ING4 could be mediated by the increased p21 expression in a p53-dependent manner, although there is no significant increase of p53 expression in HepG2 cells. Moreover, HepG2 cells with exogenous ING4 could significantly increase cell death, as exposed to some DNA-damage agents, such as etoposide and doxorubicin, implying that ING4 could enhance chemosensitivity to certain DNA-damage agents in HepG2 cells.

Acetyltransferases↗