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排序方式: 共有471条查询结果,搜索用时 46 毫秒
51.
Abdominal aortic aneurysm (AAA) is a complex remodeling process that involves both synthesis and degradation of extracellular matrix proteins in the aortic wall, leading to decreased tensile strength, progressive dilation and eventual rupture. Chronic inflammation, increased local production of elastin-degrading proteases by inflammatory cells and destruction of medial elastic lamellae play important roles in aneurysm progression. Neovascularization in all layers of the arterial wall is prominent and angiogenesis can facilitate chronic inflammation. It is still unclear what initiates aneurysmal dilation and what determines its progression. The complex nature of the process has defied elucidation. Apart from macrophages, the predominant immune cell infiltrates reported so far are CD3(+)T cells that express CD4 and CD8. Infiltrates of type 2 Th cells and their production of IL-4 and IL-5 have been implicated in AAA development. However, NKT and NK cells have a Th0 cytokine profile and can also produce type 2 as well as type 1 (IL-2 and IFNgamma) cytokines. We have demonstrated the presence of NK and NKT cells in AAA tissue. With their growing importance in autoimmunity and transplantation, they may play a role in AAA development. Therefore, there is a need to use a combination of T and NK markers to fully characterize both innate and adaptive lymphoid cell subsets in local inflammatory infiltrates in order to elucidate their roles in AAA progression. 相似文献
52.
McKay A Leung BP McInnes IB Thomson NC Liew FY 《Journal of immunology (Baltimore, Md. : 1950)》2004,172(5):2903-2908
Statins, the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors, are effective serum cholesterol-lowering agents in clinical practice, and they may also have anti-inflammatory properties. Asthma is characterized by chronic eosinophilic inflammation in the airways, which is thought to be regulated by the activity of T lymphocytes. We therefore examined the anti-inflammatory activity of simvastatin in a murine model of allergic asthma. In mice previously sensitized to OVA, simvastatin treatment, either orally or i.p., reduced the total inflammatory cell infiltrate and eosinophilia in bronchoalveolar lavage fluid in response to inhaled OVA challenge. Simvastatin therapy i.p. was also associated with a reduction in IL-4 and IL-5 levels in bronchoalveolar lavage fluid and, at higher doses, a histological reduction in inflammatory infiltrates in the lungs. OVA-induced IL-4, IL-5, IL-6, and IFN-gamma secretion was reduced in thoracic lymph node cultures from simvastatin-treated mice. Simvastatin treatment did not alter serum total IgE or OVA-specific IgG1 and IgG2a levels. These data demonstrate the therapeutic potential of statin-sensitive pathways in allergic airways disease. 相似文献
53.
Saranya Limkaisang James Henry Cunnington Liew Kon Wui Baharuddin Salleh Yukio Sato Rangsi Divarangkoon Wanwisa Fangfuk Chaiwat To-anun Susumu Takamatsu 《Mycoscience》2006,47(6):327-335
To investigate the phylogenetic relationships among the powdery mildew fungi of some economically important tropical trees
belonging to Oidium subgenus Pseudoidium, we conducted molecular phylogenetic analyses using 30 DNA sequences of the rDNA internal transcribed spacer (ITS) regions
and 26 sequences of the domains D1 and D2 of the 28S rDNA obtained from the powdery mildews on Hevea brasiliensis (para rubber tree), Anacardium occidentale (cashew), Bixa orellana, Citrus spp., Mangifera indica (mango), and Acacia spp. The results indicate that the powdery mildew fungi isolated from these tropical trees are closely related to one another.
These powdery mildews are also closely related to E. alphitoides (including Erysiphe sp. on Quercus phillyraeoides). Because of the obligate biotrophic nature of the powdery mildew fungi, the relationship between powdery mildews and their
host plants is conservative. However, the present study suggests that a particular powdery mildew species has expanded its
host ranges on a wide range of the tropical trees. This article also suggests that a powdery mildew fungus distributed in
temperate regions of the Northern Hemisphere expanded its host ranges onto tropical plants and may be a good example of how
geographical and host range expansion has occurred in the Erysiphales. 相似文献
54.
Schilthuizen M van Til A Salverda M Liew TS James SS bin Elahan B Vermeulen JJ 《Evolution; international journal of organic evolution》2006,60(9):1851-1858
Genetic divergence in geographically isolated populations is a prerequisite for allopatric speciation, one of the most common modes of speciation. In ecologically equivalent populations existing within a small, environmentally homogeneous area, an important role for environmentally neutral divergence is often found or inferred. We studied a species complex of conspicuously shaped Opisthostoma land snails on scattered limestone outcrops within a small area of lowland rainforest in Borneo. We used shell morphometrics, mitochondrial and nuclear DNA sequences, and marks of predation to study the factors involved in allopatric divergence. We found that a striking geographic divergence exists in shell morphology, which is partly associated with neutral genetic divergence. We also found geographic differentiation in the behavior of the snails' invertebrate predator and evidence of an evolutionary interaction between aspects of shell shape and predator behavior. Our study shows that adaptation to biotic aspects of the environment may play a more important role in allopatric speciation than previously suspected, even on a geographically very small scale. 相似文献
55.
Marchant J Cowper B Liu Y Lai L Pinzan C Marq JB Friedrich N Sawmynaden K Liew L Chai W Childs RA Saouros S Simpson P Roque Barreira MC Feizi T Soldati-Favre D Matthews S 《The Journal of biological chemistry》2012,287(20):16720-16733
Toxosplasma gondii is the model parasite of the phylum Apicomplexa, which contains numerous obligate intracellular parasites of medical and veterinary importance, including Eimeria, Sarcocystis, Cryptosporidium, Cyclospora, and Plasmodium species. Members of this phylum actively enter host cells by a multistep process with the help of microneme protein (MIC) complexes that play important roles in motility, host cell attachment, moving junction formation, and invasion. T. gondii (Tg)MIC1-4-6 complex is the most extensively investigated microneme complex, which contributes to host cell recognition and attachment via the action of TgMIC1, a sialic acid-binding adhesin. Here, we report the structure of TgMIC4 and reveal its carbohydrate-binding specificity to a variety of galactose-containing carbohydrate ligands. The lectin is composed of six apple domains in which the fifth domain displays a potent galactose-binding activity, and which is cleaved from the complex during parasite invasion. We propose that galactose recognition by TgMIC4 may compromise host protection from galectin-mediated activation of the host immune system. 相似文献
56.
Jukka Miettinen Aljosja Hooijer Chenghua Shi Daniel Tollenaar Ronald Vernimmen Soo Chin Liew Chris Malins Susan E. Page 《Global Change Biology Bioenergy》2012,4(6):908-918
Tropical peatlands cover over 25 Mha in Southeast Asia and are estimated to contain around 70 Gt of carbon. Peat swamp forest ecosystems are an important part of the region's natural resources supporting unique flora and fauna endemic to Southeast Asia. Over recent years, industrial plantation development on peatland, especially for oil palm cultivation, has created intense debate due to its potentially adverse social and environmental effects. The lack of objective up‐to‐date information on the extent of industrial plantations has complicated quantification of their regional and global environmental consequences, both in terms of loss of forest and biodiversity as well as increases in carbon emissions. Based on visual interpretation of high‐resolution (30 m) satellite images, we find that industrial plantations covered over 3.1 Mha (20%) of the peatlands of Peninsular Malaysia, Sumatra and Borneo in 2010, surpassing the area of Belgium and causing an annual carbon emission from peat decomposition of 230–310 Mt CO2e. The majority (62%) of the plantations were located on the island of Sumatra, and over two‐thirds (69%) of all industrial plantations were developed for oil palm cultivation, with the remainder mostly being Acacia plantations for paper pulp production. Historical analysis shows strong acceleration of plantation development in recent years: 70% of all industrial plantations have been established since 2000 and only 4% of the current plantation area existed in 1990. ‘Business‐as‐usual’ projections of future conversion rates, based on historical rates over the past two decades, indicate that 6–9 Mha of peatland in insular Southeast Asia may be converted to plantations by the year 2020, unless land use planning policies or markets for products change. This would increase the annual carbon emission to somewhere between 380 and 920 Mt CO2e by 2020 depending on water management practices and the extent of plantations. 相似文献
57.
LMO4 is a broadly expressed LIM-only protein that is involved in neural tube development and implicated in breast cancer.
Here we report backbone and side chain NMR assignments for an engineered intramolecular complex of the N-terminal LIM domain
from LMO4 tethered to residues 641–685 of C-terminal binding protein interacting protein (CtIP/RBBP8). 相似文献
58.
The Fusarium oxysporum species complex (FOSC) is a ubiquitous ascomycetous group that includes both pathogenic and non-pathogenic strains, the former being responsible for disease in over 100 cultivated plant species. Previous phylogenetic studies have uncovered at least four major clades within the FOSC, with Clade 1 hypothesised as being ancestral. However, the origin of these clades and pathogenic strains is poorly understood. Due to an emphasis on agricultural isolates in previous studies, the underlying diversity of this species complex in non-cultivated soils is largely unknown. To address this imbalance an extensive survey of isolates associated with native vegetation geographically isolated from cultivation throughout the Australian continent was conducted. A multi-gene phylogenetic analysis of the translation elongation factor (EF-1α) and the mitochondrial small subunit (mtSSU) rDNA loci did not recover any novel clades. However, the Australian isolates had high levels of intra-Clade diversity based on EF-1α sequence type (ST) comparison with a global dataset. The ST diversity was not equally distributed across the four clades, with the majority of novel STs recovered from Clade 1. Implications on the origin of the FOSC are discussed. 相似文献
59.
The aim of this study was to develop a taste-masked oral disintegrating film (ODF) containing donepezil, with fast disintegration
time and suitable mechanical strength, for the treatment of Alzheimer’s disease. Hydroxypropyl methylcellulose, corn starch,
polyethylene glycol, lactose monohydrate and crosspovidone served as the hydrophilic polymeric bases of the ODF. The uniformity,
in vitro disintegration time, drug release and the folding endurance of the ODF were examined. The in vitro results showed that 80% of donepezil hydrochloride was released within 5 minutes with mean disintegration time of 44 seconds.
The result of the film flexibility test showed that the number of folding time to crack the film was 40 times, an indication
of sufficient mechanical property for patient use. A single-dose, fasting, four-period, eight-treatment, double-blind study
involving 16 healthy adult volunteers was performed to evaluate the in situ disintegration time and palatability of ODF. Five parameters, namely taste, aftertaste, mouthfeel, ease of handling and acceptance
were evaluated. The mean in situ disintegration time of ODF was 49 seconds. ODF containing 7 mg of sucralose were more superior than saccharin and aspartame
in terms of taste, aftertaste, mouthfeel and acceptance. Furthermore, the ODF was stable for at least 6 months when stored
at 40°C and 75% relative humidity. 相似文献
60.