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91.
92.
Background
Ensemble attribute profile clustering is a novel, text-based strategy for analyzing a user-defined list of genes and/or proteins. The strategy exploits annotation data present in gene-centered corpora and utilizes ideas from statistical information retrieval to discover and characterize properties shared by subsets of the list. The practical utility of this method is demonstrated by employing it in a retrospective study of two non-overlapping sets of genes defined by a published investigation as markers for normal human breast luminal epithelial cells and myoepithelial cells. 相似文献93.
Michael Honer Thomas Ebenhan Peter R Allegrini Simon M Ametamey Mike Becquet Catherine Cannet Heidi A Lane Terence M O'Reilly Pius A Schubiger Melanie Sticker-Jantscheff Michael Stumm Paul MJ McSheehy 《Translational oncology》2010,3(4):264-275
Noninvasive functional imaging of tumors can provide valuable early-response biomarkers, in particular, for targeted chemotherapy. Using various experimental tumor models, we have investigated the ability of positron emission tomography (PET) measurements of 2-deoxy-2-[18F]fluoro-glucose (FDG) and 3′-deoxy-3′-[18F]fluorothymidine (FLT) to detect response to the allosteric mammalian target of rapamycin (mTOR) inhibitor everolimus. Tumor models were declared sensitive (murine melanoma B16/BL6 and human lung H596) or relatively insensitive (human colon HCT116 and cervical KB31), according to the IC50 values (concentration inhibiting cell growth by 50%) for inhibition of proliferation in vitro (<10 nM and >1 µM, respectively). Everolimus strongly inhibited growth of the sensitive models in vivo but also significantly inhibited growth of the insensitive models, an effect attributable to its known anti-angiogenic/vascular properties. However, although tumor FDG and FLT uptake was significantly reduced in the sensitive models, it was not affected in the insensitive models, suggesting that endothelial-directed effects could not be detected by these PET tracers. Consistent with this hypothesis, in a well-vascularized orthotopic rat mammary tumor model, other antiangiogenic agents also failed to affect FDG uptake, despite inhibiting tumor growth. In contrast, the cytotoxic patupilone, a microtubule stabilizer, blocked tumor growth, and markedly reduced FDG uptake. These results suggest that FDG/FLT-PET may not be a suitable method for early markers of response to antiangiogenic agents and mTOR inhibitors in which anti-angiogenic/vascular effects predominate because the method could provide false-negative responses. These conclusions warrant clinical testing. 相似文献
94.
95.
The reliability of 1H chemical shift calculations for DNA is assessed by comparing the experimentally and calculated chemical shifts of a reasonably large number of independently determined DNA structures. The calculated chemical shifts are based on semiempirical relations derived by Giessner-Prettre and Pullman [(1987) Q. Rev. Biophys., 20, 113–172]. The standard deviation between calculated and observed chemical shifts is found to be quite small, i.e. 0.17 ppm. This high accuracy, which is achieved without parameter adjustment, makes it possible to analyze the structural dependencies of chemical shifts in a reliable fashion. The conformation-dependent 1H chemical shift is mainly determined by the ring current effect and the local magnetic anisotropy, while the third possible effect, that of the electric field, is surprisingly small. It was further found that for a double helical environment, the chemical shift of the sugar protons, H2 to H5, is mainly affected by the ring current and magnetic anisotropy of their own base. Consequently, the chemical shift of these sugar protons is determined by two factors, namely the type of base to which the sugar ring is attached, C, T, A, or G, and secondly by the -angle. In particular, the H2 shift varies strongly with the -angle, and strong upfield H2 shifts directly indicate that the -angle is in the syn domain. The H1 shift is not only strongly affected by its own base, but also by its 3-neighboring base. On the other hand, base protons, in particular H5 of cytosine and methyl protons of thymine, are affected mainly by the 5-neighboring bases, although some effect (0.2 ppm) stems from the 3-neighboring base. The H2 protons are mainly affected by the 3-neighboring base. As a result of these findings a simple scheme is proposed for sequential assignment of resonances from B-helices based on chemical shifts. 相似文献
96.
应用免疫组织化学SP法对4例饲喂黄曲霉毒素B1的Wistar大鼠肝组织中AFB1-DNA加合物的染色及常规HE染色发现,4例肝细胞核均出现异型性,但未见肝细胞坏死、增生灶及肝细胞癌;免疫组化揭示部分肝细胞核出现棕黄色、不均质状的AFB1-DNA加合物,阳性细胞数占10~85%。结果提示免疫组织化学方法可作为一种AFB1的定位方法,AFB1在动物致癌过程中AFB1-DNA加合物可能具有启动作用 相似文献
97.
H?Bukulmez AL?Matthews CM?Sullivan C?Chen MJ?Kraay RC?Elston RW?Moskowitz VM?Goldberg ML?WarmanEmail author 《Arthritis research & therapy》2005,8(1):R25
In order to determine whether there is a genetic component to hip or knee joint failure due to idiopathic osteoarthritis (OA),
we invited patients (probands) undergoing hip or knee arthroplasty for management of idiopathic OA to provide detailed family
histories regarding the prevalence of idiopathic OA requiring joint replacement in their siblings. We also invited their spouses
to provide detailed family histories about their siblings to serve as a control group. In the probands, we confirmed the diagnosis
of idiopathic OA using American College of Rheumatology criteria. The cohorts included the siblings of 635 probands undergoing
total hip replacement, the siblings of 486 probands undergoing total knee replacement, and the siblings of 787 spouses. We
compared the prevalence of arthroplasty for idiopathic OA among the siblings of the probands with that among the siblings
of the spouses, and we used logistic regression to identify independent risk factors for hip and knee arthroplasty in the
siblings. Familial aggregation for hip arthroplasty, but not for knee arthroplasty, was observed after controlling for age
and sex, suggesting a genetic contribution to end-stage hip OA but not to end-stage knee OA. We conclude that attempts to
identify genes that predispose to idiopathic OA resulting in joint failure are more likely to be successful in patients with
hip OA than in those with knee OA. 相似文献
98.
Ancient large-scale genome duplications: phylogenetic and linkage analyses shed light on chordate genome evolution 总被引:8,自引:4,他引:8
Pebusque MJ; Coulier F; Birnbaum D; Pontarotti P 《Molecular biology and evolution》1998,15(9):1145-1159
Paralogous genes from several families were found in four human chromosome
regions (4p16, 5q33-35, 8p12-21, and 10q24-26), suggesting that their
common ancestral region underwent several rounds of large- scale
duplication. Searches in the EMBL databases, followed by phylogenetic
analyses, showed that cognates (orthologs) of human duplicated genes can be
found in other vertebrates, including bony fishes. In contrast, within each
family, only one gene showing the same high degree of similarity with all
the duplicated mammalian genes was found in nonvertebrates (echinoderms,
insects, nematodes). This indicates that large-scale duplications occurred
after the echinoderms/chordates split and before the bony vertebrate
radiation. It has been suggested that two rounds of gene duplication
occurred in the vertebrate lineage after the separation of Amphioxus and
craniate (vertebrates + Myxini) ancestors. Before these duplications, the
genes that have led to the families of paralogous genes in vertebrates must
have been physically linked in the craniate ancestor. Linkage of some of
these genes can be found in the Drosophila melanogaster and Caenorhabditis
elegans genomes, suggesting that they were linked in the triploblast
Metazoa ancestor.
相似文献
99.
Abstract The development and physiology of cord-forming saprotrophic basidiomycetes, which form extensive and persistent mycelial networks in woodland ecosystems, can be conveniently studied on non-sterile soil in laboratory microcosms mimicking field conditions. Morphological responses of Phanerochaete velutina mycelial systems to resource encounters, and decay partitioning following encounters, varied according to whether simulated woody litter was unsterile or autoclaved and on whether encounter took place at the mycelial foraging front or behind the margin (simulating litter fall onto established systems in the field). Results show that encounter of discrete resources by P. velutina is rapidly communicated to the entire mycelial system; that resource capture takes high priority at the expense of continued system extension and decay-derived carbon reallocation; and that polarized growth toward newly encountered resources, previously considered to occur infrequently with this species, may be readily detected using image analysis techniques. Potential advantages of polarized development of P. velutina are discussed. 相似文献
100.
Dimitrios Daoussis Vasileios Panoulas Tracey Toms Holly John Ioannis Antonopoulos Peter Nightingale Karen MJ Douglas Rainer Klocke George D Kitas 《Arthritis research & therapy》2009,11(4):R116-8