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21.
Leor Zach David Guez David Last Dianne Daniels Yuval Grober Ouzi Nissim Chen Hoffmann Dvora Nass Alisa Talianski Roberto Spiegelmann Zvi R. Cohen Yael Mardor 《PloS one》2012,7(12)
The current standard of care for newly diagnosed glioblastoma multiforme (GBM) is resection followed by radiotherapy with concomitant and adjuvant temozolomide. Recent studies suggest that nearly half of the patients with early radiological deterioration post treatment do not suffer from tumor recurrence but from pseudoprogression. Similarly, a significant number of patients with brain metastases suffer from radiation necrosis following radiation treatments. Conventional MRI is currently unable to differentiate tumor progression from treatment-induced effects. The ability to clearly differentiate tumor from non-tumoral tissues is crucial for appropriate patient management. Ten patients with primary brain tumors and 10 patients with brain metastases were scanned by delayed contrast extravasation MRI prior to surgery. Enhancement subtraction maps calculated from high resolution MR images acquired up to 75 min after contrast administration were used for obtaining stereotactic biopsies. Histological assessment was then compared with the pre-surgical calculated maps. In addition, the application of our maps for prediction of progression was studied in a small cohort of 13 newly diagnosed GBM patients undergoing standard chemoradiation and followed up to 19.7 months post therapy. The maps showed two primary enhancement populations: the slow population where contrast clearance from the tissue was slower than contrast accumulation and the fast population where clearance was faster than accumulation. Comparison with histology confirmed the fast population to consist of morphologically active tumor and the slow population to consist of non-tumoral tissues. Our maps demonstrated significant correlation with perfusion-weighted MR data acquired simultaneously, although contradicting examples were shown. Preliminary results suggest that early changes in the fast volumes may serve as a predictor for time to progression. These preliminary results suggest that our high resolution MRI-based delayed enhancement subtraction maps may be applied for clear depiction of tumor and non-tumoral tissues in patients with primary brain tumors and patients with brain metastases. 相似文献
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M. Perl Dvora Swartzberg S. Izhar 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1992,84(1-2):92-96
Summary Two pairs of isonuclear lines of cytoplasmic male-sterile (CMS) and fertile (F) petunia cells grown in suspension culture in the presence or absence of amino acid sources were examined for uptake of 11 amino acids and adenosine. Cells from CMS lines exhibited a significant lower rate of uptake than F cells. These differences, for various amino acids, are a result of lower affinity (high Km) values and of lower maximal velocities. Although the uptake of most of the amino acids examined was affected by the availability of energy in the cell, the differences in uptake seem to be less dependent on the energy status of the cell.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 3351-E, 1991 series 相似文献
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Louise Slot Christiansen Gabriella van Zanten Dvora Berenstein Marianne Lauridsen Søren Kjærulff Leif Søndergaard 《Nucleosides, nucleotides & nucleic acids》2016,35(10-12):699-706
ABSTRACTWe have previously found that Drosophila melanogaster only has one deoxyribonucleoside kinase, Dm-dNK, however, capable to phosphorylate all four natural deoxyribonucleosides. Dm-dNK was originally isolated from an embryonic cell line. We wanted to study the expression of Dm-dNK during development from embryonic cells to adult flies and found declining Dm-dNK activity during development and no activity in adult flies. Surprisingly, the extract from adult flies exhibited a strong inhibitory effect on deoxyribonucloside kinase activity. The dNK-inhibitor was precipitable with ammonium sulfate, and was purified to a high degree by gel-filtration as indicated by LC-MS/MS analysis. Since the inhibitor eluted from G-200 gel-filtration with a size of 10–13 kDa, we named it P12. We tested the purified fraction for specificity towards various enzymes and found that both mammalian and bacterial dNKs were inhibited, whereas there was no effect on hexokinase and pyruvate kinases and acidic phosphatase. However, when tested against cyclin B-dependent kinase, we found a strong inhibitory effect. Both with human Cdk1/CycB and S. pombe Cdc2/B-type cyclin the purified fraction from Superdex 200 that inhibited Dm-dNK, also inhibited the two protein kinases to the same degree. Furthermore, testing P12 in a DNA polymerase based assay we found that the 3′-5′-exonuclease part of the DNA polymerase (Klenow polymerase) was activated. 相似文献
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W A Hook E H Berenstein F U Zinsser C Fischler R P Siraganian 《Journal of immunology (Baltimore, Md. : 1950)》1991,147(8):2670-2676
mAb were selected that inhibited IgE-mediated histamine release from human basophils. The two mAb, HB 9AB6 and HB 10AB2, are of the IgG1 subclass and have a 50% inhibitory concentration of 0.16 to 1.1 micrograms/ml. The mAb required several hours of incubation with the basophils at 37 degrees C to induce maximum inhibition. Neither mAb directly released histamine from human basophils nor did they inhibit release induced by formylmethionine tripeptide, calcium ionophore A23187, or PMA. There was little inhibition of IgE-mediated release when the cells were preincubated with the mAb at 4 degrees C. By FACS analysis the 2 mAb bound to all peripheral blood leukocytes and immunoprecipitated a approximately 200-kDa protein from peripheral blood leukocytes and several cell lines of human origin. In binding studies and by sequential immunoprecipitation the 2 mAb and a known anti-CD45 mAb bound to the same protein. However, the mAb recognized different epitopes. Therefore, mAb to the CD45 surface Ag, a membrane protein tyrosine phosphatase, inhibits IgE-receptor mediated histamine release from human basophils. The data suggest a link between protein tyrosine phosphorylation and high affinity IgE receptor-mediated signal transduction in human basophils. 相似文献
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Isolation of two cDNA clones from tomato containing two different superoxide dismutase sequences 总被引:6,自引:0,他引:6
Rafael Perl-Treves Benedetta Nacmias Dvora Aviv Elisha P. Zeelon Esra Galun 《Plant molecular biology》1988,11(5):609-623
A cDNA library was derived from the poly(A)+ RNA of young tomato leaves. The library was cloned in a gt11 system and screened by synthetic oligonucleotide probes having sequences that match the codes of conserved regions of amino acid sequences of Cu,Zn superoxide dismutase (SOD) proteins from a wide range of eukaryotic organisms. Two cDNAs were isolated, cloned and sequenced. One of the cDNAs, P31, had a full-size open reading frame of 456 bp with a deduced amino acid sequence having an 80% homology with the deduced amino acid sequence of the cytosolic SOD-2 cDNA of maize. The other cDNA, T10 (extended by T1), had a 651 bp open reading frame that revealed, upon computer translation, 90% homology to the amino acid sequence of mature spinach chloroplast SOD. The 5 end of the reading frame seems to code for a putative transit peptide. This work thus suggests for the first time an amino acid sequence for the transit peptide of chloroplast SOD. Northern hybridizations indicated that each of the P31 and T10 clones hybridized to a blotted poly(A)+ RNA species. These two species are differentially expressed in the plant organs: e.g., the species having the T10 sequence was detected in the leaves but not in roots, while the one with the P31 sequence was expressed in both leaves and roots. The cDNA clones P31 and T10 were also hybridized to Southern blots of endonuclease fragmented tomato DNA. The clones hybridized to specific fragments and no cross hybridization between the two clones was revealed under stringent hybridization conditions; the hybridization pattern indicated that, most probably, only one locus is coding for each of the two mRNA species. 相似文献
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Ferguson W Dvora S Fikes RW Stone AC Boissinot S 《Molecular biology and evolution》2012,29(4):1093-1103
Oligoadenylate synthetases (OAS) are interferon-induced enzymes that participate in the first line of defense against a wide range of viral infection in animals. Upon activation by viral double-stranded RNA, OAS synthesizes (2-5) oligoadenylates, which activate RNase L, leading to the nonspecific degradation of cellular and viral RNA. Some association studies in humans suggest that variation at one of the OAS genes, OAS1, could be influencing host susceptibility to viral infection. We assessed the diversity of OAS1 in hominoid primates with a focus on chimpanzees. We found that the OAS1 gene is extremely polymorphic in Central African chimpanzee and exhibits levels of silent and replacement diversity much higher than neutral regions of the chimpanzee genome. This level of variation strongly suggests that balancing selection is acting on OAS1, and indeed, this conclusion was validated by several tests of neutrality. We further demonstrated that balancing selection has been acting at this locus since the split between chimpanzees, humans, and gorillas (~8.6 Ma) and caused the persistence of two deeply divergent allelic lineages in Central African chimpanzees. These two groups of OAS1 alleles differ by a large number of amino acids (a.a.), including several a.a. putatively involved in RNA binding. It is therefore very likely that variation at the OAS1 locus affects the innate immune response of individuals to specific viral infection. Our data strongly suggest that interactions between viral RNA and OAS1 are responsible for the maintenance of ancestral polymorphisms at this locus for at least 13.2 My. 相似文献