696 research outputs found

    Pharmacogenomics and the Yin/Yang actions of ginseng: anti-tumor, angiomodulating and steroid-like activities of ginsenosides.

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    In Chinese medicine, ginseng (Panax ginseng C.A. Meyer) has long been used as a general tonic or an adaptogen to promote longevity and enhance bodily functions. It has also been claimed to be effective in combating stress, fatigue, oxidants, cancer and diabetes mellitus. Most of the pharmacological actions of ginseng are attributed to one type of its constituents, namely the ginsenosides. In this review, we focus on the recent advances in the study of ginsenosides on angiogenesis which is related to many pathological conditions including tumor progression and cardiovascular dysfunctions. Angiogenesis in the human body is regulated by two sets of counteracting factors, angiogenic stimulators and inhibitors. The 'Yin and Yang' action of ginseng on angiomodulation was paralleled by the experimental data showing angiogenesis was indeed related to the compositional ratio between ginsenosides Rg1 and Rb1. Rg1 was later found to stimulate angiogenesis through augmenting the production of nitric oxide (NO) and vascular endothelial growth factor (VEGF). Mechanistic studies revealed that such responses were mediated through the PI3K-->Akt pathway. By means of DNA microarray, a group of genes related to cell adhesion, migration and cytoskeleton were found to be up-regulated in endothelial cells. These gene products may interact in a hierarchical cascade pattern to modulate cell architectural dynamics which is concomitant to the observed phenomena in angiogenesis. By contrast, the anti-tumor and anti-angiogenic effects of ginsenosides (e.g. Rg3 and Rh2) have been demonstrated in various models of tumor and endothelial cells, indicating that ginsenosides with opposing activities are present in ginseng. Ginsenosides and Panax ginseng extracts have been shown to exert protective effects on vascular dysfunctions, such as hypertension, atherosclerotic disorders and ischemic injury. Recent work has demonstrates the target molecules of ginsenosides to be a group of nuclear steroid hormone receptors. These lines of evidence support that the interaction between ginsenosides and various nuclear steroid hormone receptors may explain the diverse pharmacological activities of ginseng. These findings may also lead to development of more efficacious ginseng-derived therapeutics for angiogenesis-related diseases

    Spatially resolved Spectro-photometry of M81: Age, Metallicity and Reddening Maps

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    In this paper, we present a multi-color photometric study of the nearby spiral galaxy M81, using images obtained with the Beijing Astronomical Observatory 60/90 cm Schmidt Telescope in 13 intermediate-band filters from 3800 to 10000{\AA}. The observations cover the whole area of M81 with a total integration of 51 hours from February 1995 to February 1997. This provides a multi-color map of M81 in pixels of 1\arcsec.7 \times 1\arcsec.7. Using theoretical stellar population synthesis models, we demonstrate that some BATC colors and color indices can be used to disentangle the age and metallicity effect. We compare in detail the observed properties of M81 with the predictions from population synthesis models and quantify the relative chemical abundance, age and reddening distributions for different components of M81. We find that the metallicity of M81 is about Z=0.03Z=0.03 with no significant difference over the whole galaxy. In contrast, an age gradient is found between stellar populations of the central regions and of the bulge and disk regions of M81: the stellar population in its central regions is older than 8 Gyr while the disk stars are considerably younger, 2\sim 2 Gyr. We also give the reddening distribution in M81. Some dust lanes are found in the galaxy bulge region and the reddening in the outer disk is higher than that in the central regions.Comment: Accepted for publication in AJ (May 2000 issue). 27 pages including 6 figures. Uses AASTeX aasms4 styl

    Preparation of Polyvinyl Alcohol /Silver Nanoparticles Film and Its Application in Fresh Noodles Leaf Preservation

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    In this study, polyvinyl alcohol (PVA) and distilled water were used as raw materials, glycerol was used as plasticizer. The PVA/AgNPs composite films with different proportions of silver nanoparticles (0%, 1%, 2% and 4%) were prepared by solution casting method. The mechanical properties, barrier property and antibacterial property of the films were characterized. The suitable film was applied to the fresh-keeping of fresh noodles leaf, and its effect on the quality of fresh noodles leaf was studied. The results showed that 4% PVA/AgNPs films had better mechanical properties, barrier properties and antibacterial properties. The diameter of the inhibitory circle against Staphylococcus aureus reached 11.67±0.29 mm. PVA/AgNPs film with 4% nano-silver content was selected to preserve fresh noodles leaf and determine the quality changes of fresh noodles leaf during the storage period at 4 ℃. The preservation results showed that 4% PVA/AgNPs film could significantly delayed the growth of total colony counts, maintained the color, pH and acidity of the fresh noodles leaf during the storage period. Furthermore, 4% PVA/AgNPs film significantly reduced the cooking loss, improved the quality and the migration of the silver in the fresh noodles leaf, which the national standards. The above study showed that PVA/AgNPs film had the excellent antibacterial effect, and effectively maintained the quality of fresh noodle leaf and prolong the storage time, which can provide a new method for the packaging of noodle products

    Fossil Seed from the Miocene Shihti Formation of Taiwan

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    A compressed fossil seed, described as Carpolithes sp., is found in the coal-bearing Miocene Shihti Formation from the Lifeng coal mine, Sanshia District of the New Taipei City. The fossil is generally rounded with a diameter of ca. 10 mm in lateral view. The anatomical features of the testa epidermal cells were observed using anatomical analysis. The anatomical features of the megafossil organ from the Formation are reported for the first time

    Discovery of a new species of the subgenus Japonigekko (Squamata, Gekkonidae, Gekko) from the Hengduan Mountains, southwestern China: the best Japonigekko mountaineer

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    A new Gekko (subgenus Japonigekko) species, Gekko alpinus sp. nov., is described from the Jinsha River Basin in southwestern China, between the border of Mangkang County, Xizang Autonomous Region and Batang County, Sichuan Province, according to the integrative taxonomic results combining molecular data and morphological characters obtained from the type series comprising 11 specimens. Our molecular phylogeny inferred from the mitochondrial 16S and ND2 gene fragments indicated that this new species is most closely related to Gekko jinjiangensis, but a considerable amount of genetic divergence exists between them (p-distance: 3.6%-4.1% (16S) and 7.1%–9.1% (ND2)). The new species can be distinguished from its congeners via a combination of series morphological characters. The discovery of this new species marks the highest altitudinal range (2400 to 2542 m a.s.l.) recorded for the subgenus Japonigekko and also represents a new provincial record for the genus in Xizang Autonomous Region

    MiR-181b sensitizes glioma cells to teniposide by targeting MDM2

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    Background: Although the incidence of glioma is relatively low, it is the most malignant tumor of the central nervous system. The prognosis of high-grade glioma patient is very poor due to the difficulties in complete resection and resistance to radio-/chemotherapy. Therefore, it is worth investigating the molecular mechanisms involved in glioma drug resistance. MicroRNAs have been found to play important roles in tumor progression and drug resistance. Our previous work showed that miR-181b is involved in the regulation of temozolomide resistance. In the current study, we investigated whether miR-181b also plays a role in antagonizing the effect of teniposide.Methods: MiR-181b expression was measured in 90 glioma patient tissues and its relationship to prognosis of these patients was analyzed. Cell sensitivity to teniposide was tested in 48 primary cultured glioma samples. Then miR-181b stably overexpressed U87 cells were generated. The candidate genes of miR-181b from our previous study were reanalyzed, and the interaction between miR-181b and target gene MDM2 was confirmed by dual luciferase assay. Cell sensitivity to teniposide was detected on miR-181b over expressed and MDM2 down regulated cells.Results: Our data confirmed the low expression levels of miR-181b in high-grade glioma tissues, which is related to teniposide resistance in primary cultured glioma cells. Overexpression of miR-181b increased glioma cell sensitivity to teniposide. Through target gene prediction, we found that MDM2 is a candidate target of miR-181b. MDM2 knockdown mimicked the sensitization effect of miR-181b. Further study revealed that miR-181b binds to the 3'-UTR region of MDM2 leading to the decrease in MDM2 levels and subsequent increase in teniposide sensitivity. Partial restoration of MDM2 attenuated the sensitivity enhancement by miR-181b.Conclusions: MiR-181b is an important positive regulator on glioma cell sensitivity to teniposide. It confers glioma cell sensitivity to teniposide through binding to the 3'-UTR region of MDM2 leading to its reduced expression. Our findings not only reveal the novel mechanism involved in teniposide resistance, but also shed light on the optimization of glioma treatment in the future.Department of Health Technology and Informatic

    β-carboline alkaloids from Trigonostemon filipes and Trigonostemon lii

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    Six β-carboline alkaloids including three new ones, trifilines A-C (1–3) were isolated from Trigonostemon filipes, along with a new β-carboline alkaloid, trigonoine C (7) isolated from Trigonostemon lii. Their structures were elucidated by extensive spectroscopic techniques. Trifilines A (1) and B (2) showed weak anti-HIV-1 activity with EC(50) values of 54.61 µg/mL and 9.75 µg/mL, along with TI (Therapeutic index) values of 1.52 and 1.42, respectively. This is the first time to report the chemical constituents of Trigonostemon filipes. [Image: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material is available for this article at 10.1007/s13659-012-0028-x and is accessible for authorized users
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