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21.
Matrix metalloproteinases (MMPs) are essential contributors to a microenvironment that promotes tumour progression. During the two last decades, inhibition of MMPs has become the focus of considerable interest for cancer therapy, and numerous synthetic metalloproteinase inhibitors have been developed by the pharmaceutical industry. However, clinical trials have shown disappointing efficacy or unexpected toxicity and new targets are thus eagerly awaited. The identification of endocytic clearance of several MMPs by the low-density lipoprotein receptor-related protein (LRP) might provide insight into novel strategies for controlling MMP level during malignant processes. This review attempts to summarize recent aspects on the cellular and molecular basis of LRP-mediated endocytic disposal of MMPs. 相似文献
22.
Georges A. Bécus 《Bulletin of mathematical biology》1979,41(4):543-554
The formalism and results of the theory of random evolutions are used to establish and investigate a model for two randomly
interacting populations. The asymptotic stability of the expected solution is studied and contrasted to that of the associated
deterministic system. 相似文献
23.
Facilitation in plant communities: the past, the present, and the future 总被引:24,自引:11,他引:24
Rob W. Brooker Fernando T. Maestre Ragan M. Callaway Christopher L. Lortie Lohengrin A. Cavieres Georges Kunstler Pierre Liancourt Katja Tielbörger Justin M. J. Travis Fabien Anthelme Cristina Armas Lluis Coll Emmanuel Corcket Sylvain Delzon Estelle Forey Zaal Kikvidze Johan Olofsson Francisco Pugnaire Constanza L. Quiroz Patrick Saccone Katja Schiffers Merav Seifan Blaize Touzard Richard Michalet 《Journal of Ecology》2008,96(1):18-34
24.
Serge Andréfouët Simon Van Wynsberge Cécile Fauvelot Andrew W. Bruckner Georges Remoissenet 《Molluscan research.》2014,34(4):277-284
The giant clam subfamily Tridacninae (family Cardiidae) is an important group of bivalve molluscs found throughout the Red Sea and Indo-Pacific, from East Africa to the Eastern Pacific biogeographic region. The Tridacna genus is currently revised with numerous cryptic species identified with molecular markers. New Tridacna records from the fringe of the known distribution areas are extremely useful to identify genetically unique species, geographic ranges, and to examine processes associated with species differentiation. While Tridacna maxima is abundant in French Polynesia (Central South Pacific Ocean) the larger fluted giant clam Tridacna squamosa was formerly reported only in the Austral Islands in the south. Following a recent survey that spanned 23 islands and atolls of the Society, Tuamotu and Gambier Archipelagos, the presence of T. squamosa between the Cook Islands and Pitcairn Islands is confirmed using both morphological and molecular information, suggesting a relic distribution across the Central Pacific Ocean. Tridacna squamosa is rare, but present throughout Tuamotu and Gambier. However, it remained undetected from the Society Islands, probably due to historical over-fishing. This species is valued by local inhabitants, and is sought after mainly as gifts and also for a limited local shell trade. The rarity of T. squamosa may call for conservation measures in the near future. 相似文献
25.
Georges TawilAnders Viksø-Nielsen Agnès Rolland-SabatéPaul Colonna Alain Buléon 《Carbohydrate polymers》2012,87(1):46-52
A new α-amylase from Anoxybacillus flavothermus (AFA) was found to be effective in hydrolyzing raw starch in production of glucose syrup at temperatures below the starch gelatinization temperature. AFA is very efficient, leading to 77% hydrolysis of a 31% raw starch suspension. The final hydrolysis degree is reached in 2-3 h at starch concentrations lower than 15% and 8-24 h at higher concentrations. AFA is also very efficient in hydrolyzing the crystalline domains in the starch granule. The major A-type crystalline structure is more rapidly degraded than amorphous domains in agreement with the observed preferential hydrolysis of amylopectin. Amylose-lipid complexes are degraded in a second step, yielding amylose fragments which then re-associate into B-type crystalline structures forming the final α-amylase resistant fraction. The mode of action of AFA and the factors limiting complete hydrolysis are discussed in details. 相似文献
26.
The neo-vascularization of the host site is crucial for the primary fixation and the long-term stability of the bone-implant interface. Our aim was to investigate the progression of endothelial cell population in the first weeks of healing. We proposed a theoretical reactive model to study the role of initial conditions, random motility, haptotaxis and chemotaxis in interactions with fibronectin factors and transforming angiogenic factors. The application of governing equations concerned a canine experimental implant and numerical experiments based upon statistical designs of experiments supported the discussion. We found that chemotaxis due to transforming angiogenic factors was attracting endothelial cells present into the host bone. Haptotaxis conditioned by fibronectin factors favored cells adhesion to the host bone. The combination of diffusive and reactive effects nourished the wave front migration of endothelial cells from the host bone towards the implant. Angiogenesis goes together with new-formed bone formation in clinics, so the similarity of distribution patterns of mineralized tissue observed in-vivo and the spatio-temporal concentration of endothelial cells predicted by the model, tended to support the reliability of our theoretical approach. 相似文献
27.
Fabrice Prunier Gwenola Terrien Yannick Le Corre Ailea L. Y. Apana Lo?c Bière Gilles Kauffenstein Alain Furber Arthur A. B. Bergen Theo G. M. F. Gorgels Olivier Le Saux Georges Leftheriotis Ludovic Martin 《PloS one》2013,8(7)
Background
Pseudoxanthoma elasticum (PXE), caused by mutations in the ABCC6 gene, is a rare multiorgan disease characterized by the mineralization and fragmentation of elastic fibers in connective tissue. Cardiac complications reportedly associated with PXE are mainly based on case reports.Methods
A cohort of 67 PXE patients was prospectively assessed. Patients underwent physical examination, electrocardiogram, transthoracic echocardiography, cardiac magnetic resonance imaging (CMR), treadmill testing, and perfusion myocardial scintigraphy (SPECT). Additionally, the hearts of a PXE mouse models (Abcc6−/−) and wild-type controls (WT) were analyzed.Results
Three patients had a history of proven coronary artery disease. In total, 40 patients underwent exercise treadmill tests, and 28 SPECT. The treadmill tests were all negative. SPECT showed mild perfusion abnormalities in two patients. Mean left ventricular (LV) dimension and function values were within the normal range. LV hypertrophy was found in 7 (10.4%) patients, though the hypertrophy etiology was unknown for 3 of those patients. Echocardiography revealed frequent but insignificant mitral and tricuspid valvulopathies. Mitral valve prolapse was present in 3 patients (4.5%). Two patients exhibited significant aortic stenosis (3.0%). While none of the functional and histological parameters diverged significantly between the Abcc6−/− and WT mice groups at age of 6 and 12 months, the 24-month-old Abcc6−/− mice developed cardiac hypertrophy without contractile dysfunction.Conclusions
Despite sporadic cases, PXE does not appear to be associated with frequent cardiac complications. However, the development of cardiac hypertrophy in the 24-month-old Abcc6−/− mice suggests that old PXE patients might be prone to developing late cardiopathy. 相似文献28.
29.
Oleg Mediannikov Khalid El Karkouri Georges Diatta Catherine Robert Pierre-Edouard Fournier Didier Raoult 《Standards in genomic sciences》2013,8(2):279-289
Bartonella senegalensis sp. nov. strain OS02T is the type strain of B. senegalensis sp. nov., a new species within the genus Bartonella. This strain, whose genome is described here, was isolated in Senegal from the soft tick Ornithodoros sonrai, the vector of relapsing fever. B. senegalensis is an aerobic, rod-shaped, Gram-negative bacterium. Here we describe the features of this organism, together with the complete genome sequence and its annotation. The 1,966,996 bp-long genome contains 1,710 protein-coding and 46 RNA genes, including 6 rRNA genes. 相似文献
30.
The immunogenicity and reactogenicity of the Urabe Am 9 mumps virus vaccine strain were studied after the administration of different doses of the vaccine to 197 children ranging in age from seven and a half months to nine years and without a history of mumps. There was no effect of dose on the response in serum neutralizing antibodies in the range of 10(2.9) to 10(4.7) TCID50/dose. In the 90 subjects without detectable serum neutralization antibodies before vaccination seroconversion was obtained in 94.4% after 42 days. Half of a group of 34 seropositive children who were tested also showed a fourfold or greater rise in antibodies. Persistence of vaccine-enhanced haemagluttinin-inhibition (EHI) antibodies was satisfactory as only two of 46 vaccinees followed-up for between 27 and 32 months had undetectable levels of EHI antibodies and the geometric mean titre of vaccine-induced EHI antibodies had only fallen to about one-third by 32 months after vaccination. Although there was serological evidence of a subclinical re-infection in three subjects, to date none of the vaccinees has had clinical mumps indicating that the vaccine confers protection against disease. The vaccine was well tolerated. Furthermore, the majority of the few 'reactions' reported were probably not vaccine-related. It is concluded that the Urabe Am 9 is an acceptable strain for use in live mumps vaccines. 相似文献