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81.
Nezhun Gören Ayhan Ulubelen Jasmin Jakupovic Ferdinand Bohlmann Michael Grenz 《Phytochemistry》1984,23(10):2281-2284
In addition to known compounds an investigation of the fruits of Smyrnium rotundifolium afforded four new germacrane derivatives, all closely related to glechomanolide, one being a secogermacrane anhydride. The new compounds were 8,9-epoxy-8,9-secoglechomanolide, 1β,10α-epoxy-4-methoxy-8-hydroxyglechomanolide and 8-oxo-8,9-secoglechomanolide. The structures were assigned by spectral methods as well as by some chemical reactions. 相似文献
82.
Reinvestigation of the aerial parts of Pluchea dioscoridis afforded, in addition to known compounds, five new eudesmanolides and a new thiophene derivative. The stereochemistry of one of the eudesmanolides isolated previously has been corrected. The structures were elucidated by spectroscopic methods. 相似文献
83.
Microtubule dynamics in living root hairs: transient slowing by lipochitin oligosaccharide nodulation signals 总被引:6,自引:0,他引:6
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The incorporation of a fusion of green fluorescent protein and tubulin-alpha 6 from Arabidopsis thaliana in root hairs of Lotus japonicus has allowed us to visualize and quantify the dynamic parameters of the cortical microtubules in living root hairs. Analysis of individual microtubule turnover in real time showed that only plus polymer ends contributed to overall microtubule dynamicity, exhibiting dynamic instability as the main type of microtubule behavior in Lotus root hairs. Comparison of the four standard parameters of in vivo dynamic instability--the growth rate, the disassembly rate, and the frequency of transitions from disassembly to growth (rescue) and from growth to disassembly (catastrophe)--revealed that microtubules in young root hairs were more dynamic than those in mature root hairs. Either inoculation with Mesorhizobium loti or purified M. loti lipochitin oligosaccharide signal molecules (Nod factors) significantly affected the growth rate and transition frequencies in emerging and growing root hairs, making microtubules less dynamic at a specific window after symbiotic inoculation. This response of root hair cells to rhizobial Nod factors is discussed in terms of the possible biological significance of microtubule dynamics in the early signaling events leading to the establishment and progression of the globally important Rhizobium/legume symbiosis. 相似文献
84.
85.
Hååg P Bektic J Bartsch G Klocker H Eder IE 《The Journal of steroid biochemistry and molecular biology》2005,96(3-4):251-258
We investigated the effects of androgen receptor (AR) down regulation with a small interference RNA molecule (siRNA_AR(start)) on androgen sensitive LNCaP and androgen independent LNCaPabl prostate cancer cells, the latter representing an in vitro model for the development of therapy resistance in prostate cancer. Although LNCaPabl cells express increased levels of AR in comparison with androgen sensitive LNCaP cells, the protein was significantly down regulated in response to siRNA_AR(start) treatment. This AR down regulation resulted in a marked cell growth inhibition in both cell lines. By contrast, DU-145 prostate cancer cells, which lack AR expression, were not inhibited by the siRNA_AR(start). In consequence to AR down regulation, both cell lines, LNCaP and LNCaPabl, shared a highly similar gene expression profile in terms of major changes in cell cycle regulatory genes. The cell cycle inhibitor p21(Waf1/Cip1) as well as cyclin D1 were significantly up regulated by siRNA_AR(start) treatment, considering a switch in cyclin expression towards cell cycle retardation. Control molecules had moderate effects on cell proliferation and gene expression, respectively. In summary, we found that AR inhibition with siRNA induces cell growth retardation in androgen sensitive as well as in androgen independent prostate cancer cells and thus may represent an interesting approach to combat hormone-refractory prostate cancer. 相似文献
86.
Jasmin Arrich Franz Piribauer Philipp Mad Daniela Schmid Klaus Klaushofer Marcus Müllner 《CMAJ》2005,172(8):1039-1043
Background
Osteoarthritis of the knee affects up to 10% of the elderly population. The condition is frequently treated by intra-articular injection of hyaluronic acid. We performed a systematic review and meta-analysis of randomized controlled trials to assess the effectiveness of this treatment.Methods
We searched MEDLINE, EMBASE, CINAHL, BIOSIS and the Cochrane Controlled Trial Register from inception until April 2004 using a combination of search terms for knee osteoarthritis and hyaluronic acid and a filter for randomized controlled trials. We extracted data on pain at rest, pain during or immediately after movement, joint function and adverse events.Results
Twenty-two trials that reported usable quantitative information on any of the predefined end points were identified and included in the systematic review. Even though pain at rest may be improved by hyaluronic acid, the data available from these studies did not allow an appropriate assessment of this end point. Patients who received the intervention experienced a reduction in pain during movement: the mean difference on a 100-mm visual analogue scale was –3.8 mm (95% confidence interval [CI] –9.1 to 1.4 mm) after 2–6 weeks, –4.3 mm (95% CI –7.6 to –0.9 mm) after 10–14 weeks and –7.1 mm (95% CI –11.8 to –2.4 mm) after 22–30 weeks. However, this effect was not compatible with a clinically meaningful difference (expected to be about 15 mm on the visual analogue scale). Furthermore, the effect was exaggerated by trials not reporting an intention-to-treat analysis. No improvement in knee function was observed at any time point. Even so, the effect of hyaluronic acid on knee function was more favourable when allocation was not concealed. Adverse events occurred slightly more often among patients who received the intervention (relative risk 1.08, 95% CI 1.01 to 1.15). Only 4 trials explicitly reported allocation concealment, had blinded outcome assessment and presented intention-to-treat data.Interpretation
According to the currently available evidence, intra-articular hyaluronic acid has not been proven clinically effective and may be associated with a greater risk of adverse events. Large trials with clinically relevant and uniform end points are necessary to clarify the benefit–risk ratio.Osteoarthritis affects about 10% of the population over 55 years of age. Of those, one-quarter are severely disabled.1 The condition is characterized by degeneration of the articular cartilage and subsequent subchondral bone changes. The underlying mechanisms remain unknown, but the glycosaminoglycan–proteoglycan matrix may play a major role.2Hyaluronic acid, a glycosaminoglycan, is widely used for the treatment of osteoarthritis of the knee. A survey of 2 general practices in the United Kingdom showed that about 15% of patients with osteoarthritis received intra-articular treatment with glucosamine sulfates.3 The costs of such treatment are significant. At present, 1 syringe of hyaluronic acid costs at least Can$130 (US$110). The treatment of knee osteoarthritis is covered by the US Medicare program but not by provincial formularies in Canada. In Austria (which has 8 million inhabitants) more than 10 million euros (approximately US$12 million or Can$15 million) is spent by social insurance programs annually for hyaluronic acid preparations (excluding the cost of application).Hyaluronic acid has beneficial effects in vitro.4 Because of its viscoelastic quality, it may replace synovial fluid. Furthermore, it may reduce the perception of pain. Beneficial molecular and cellular effects have also been reported.2,4 Hyaluronic acid is frequently applied by intra-articular injection, but the evidence concerning its clinical relevance is conflicting. The European League against Rheumatism (EULAR) recommends the intra-articular application of hyaluronic acid as “category 2” evidence (at least 1 controlled study without randomization).5 The American College of Rheumatology recommends intra-articular hyaluron therapy for patients with no response to nonpharmacologic therapy and simple analgesics.6 In contrast, other specialists have concluded that “hyaluronate sodium is not efficacious” in the treatment of osteoarthritis.7 The first state-of-the-art systematic review and meta-analysis was published recently,8 and its authors concluded “that intra-articular hyaluronic acid, at best, has a small effect.” We performed a systematic review and meta-analysis of the effect of intra-articular hyaluronic acid for the treatment of osteoarthritis of the knee. In contrast to 2 previous meta-analyses on this subject,8,9 we used a different approach to data synthesis and interpretation: instead of analyzing a composite effect size over time, we allocated trial data, when possible, to 3 outcome groups that we assumed would be relevant for patients with osteoarthritis. We specifically looked at pain at rest, pain during exercise and joint function as distinct outcomes, measured repeatedly over time. In addition, we assessed adverse events and the impact of both trial quality and molecular mass of the product. This analysis allows us to provide important additional insight into the effects of intra-articular administration of hyaluronic acid for the treatment of osteoarthritis of the knee. 相似文献87.
Microvascular endothelial cells from human neonatal foreskin were grown in vitro until a three-dimensional network of capillary-like structures was formed. All stages of the angiogenic cascade could be observed in this in vitro model, including the formation of an internal lumen. The microscopy focused on morphology, formation of an internal lumen, role of the extracellular matrix, polarity of the cells, and the time-course of the angiogenic cascade. Bright-field microscopy revealed cells arranged circularly side by side and the internal lumen of capillary-like structures was verified by electron microscopy. Immunolabeling revealed a peritubular localization of collagen IV. Reporter gene expression after the formation of capillary-like structures was marginally higher than control expression, but clearly lower than the expression of cells at the stage of proliferation. Highest transfection efficiencies were obtained using vectors with the CMV promoter and the long fragment of the Ets-1 promoter. This is a first study of transfection efficiencies mapped for stages of in vitro angiogenesis. We describe here the morphological features of a long-term in vitro model of angiogenesis of human microvascular endothelial cells that could be used for transfection studies, without the provision of an extracellular matrix substrate. The cells self-create their own extracellular matrix to proliferate and form a three-dimensional network of capillary-like structures with an internal lumen. 相似文献
88.
N.?VassilevEmail author I.?Nikolaeva M.?Vassileva 《Reviews in Environmental Science and Biotechnology》2005,4(4):235-243
Arbuscular mycorrhizal fungi is an important group of soil microorganisms which form beneficial symbiotic associations with
roots with a wide range of plants thus improving plant growth, nutrition and health. This paper reviews the current status
of preparation and formulation of mycorrhizal inoculum applying polymer materials with determined characteristics. The most
widely used methods are based on the entrapment of fungal materials in natural polysaccharide gels. The potential of such
inoculant preparations is illustrated by various studies which include immobilization of mycorrhized root pieces, vesicles
and spores, in some cases co-entrapped with other plant beneficial microorganisms. Suggestions for further research in this
field are also discussed. 相似文献
89.
Neointima formation is a process characterized by smooth muscle cell (SMC) proliferation and extracellular matrix deposition in the vascular intimal layer. Here, we critically evaluate the role of caveolin-1 (Cav-1) in the pathogenesis of neointima formation. Cav-1 and caveolae organelles are particularly abundant in SMCs, where they are thought to function in membrane trafficking and signal transduction events. To directly evaluate the role of Cav-1 in the pathogenesis of neointimal lesions, we used Cav-1-deficient (Cav-1 -/-) mice as a model system. The right common carotid artery of wild-type and Cav-1 -/- mice was ligated just proximal to its bifurcation. Specimens were then harvested 4-weeks postligation and processed for morphometric and immunohistochemical analyses. The carotids of Cav-1 -/- mice showed significantly more intimal hyperplasia with subtotal luminal obstruction, as compared to wild-type mice. These neointimal lesions consisted mainly of SMCs. Mechanistically, neointimal lesions derived from Cav-1 -/- mice exhibited higher levels of phospho-p42/44 MAP kinase and cyclin D1 immunostaining, consistent with the idea that Cav-1 functions as a negative regulator of signal transduction. A significant increase in phospho-Rb (Ser780) immunostaining was also observed, in line with the upregulation of cyclin D1. In conclusion, using a carotid artery blood-flow cessation model, we show that genetic ablation of Cav-1 in mice stimulates SMC proliferation (neointimal hyperplasia), with concomitant activation of the p42/44 MAP kinase cascade and upregulation of cyclin D1. Importantly, our current study is the first to investigate the role of Cav-1 in SMC proliferation in the vascular system using Cav-1 -/- mice. 相似文献
90.
Satellite glial cells (SGCs) tightly envelop the perikarya of primary sensory neurons in peripheral ganglion and are identified by their morphology and the presence of proteins not found in ganglion neurons. These SGC-unique proteins include the inwardly rectifying K(+) channel Kir4.1, the connexin-43 (Cx43) subunit of gap junctions, the purinergic receptor P2Y4 and soluble guanylate cyclase. We also present evidence that the small-conductance Ca(2+)-activated K(+) channel SK3 is present only in SGCs and that SGCs divide following nerve injury. All the above proteins are involved, either directly or indirectly, in potassium ion (K(+)) buffering and, thus, can influence the level of neuronal excitability, which, in turn, has been associated with neuropathic pain conditions. We used in vivo RNA interference to reduce the expression of Cx43 (present only in SGCs) in the rat trigeminal ganglion and show that this results in the development of spontaneous pain behavior. The pain behavior is present only when Cx43 is reduced and returns to normal when Cx43 concentrations are restored. This finding shows that perturbation of a single SGC-specific protein is sufficient to induce pain responses and demonstrates the importance of PNS glial cell activity in the pathophysiology of neuropathic pain. 相似文献