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101.
Raffaele P. Bonomo Vincenzo Cucinotta Franca D'Alessandro Giuseppe Impellizzeri Giuseppe Maccarrone Enrico Rizzarelli Graziella Vecchio Lorenza Carima Roberto Corradini Giorgio Sartor Rosangela Marchelli 《Chirality》1997,9(4):341-349
A modified β-cyclodextrin bearing a 2-aminomethylpyridine binding site for copper(II) (6-deoxy-6-[N-(2-methylamino)pyridine)]-β-cyclodextrin, CDampy was synthesized by C6-monofunctionalization. The acid-base properties of the new ligand in aqueous solution were investigated by potentiometry and calorimetry, and its conformations as a function of pH were studied by NMR and circular dichroism (c.d.). The formation of binary copper(II) complexes was studied by potentiometry, EPR, and c.d. The copper(II) complex was used as chiral selector for the HPLC enantiomeric separation of underivatized aromatic amino acids. Enantioselectivity in the overall stability constants of the ternary complexes with D- or L-Trp was detected by potentiometry, whereas the complexes of the Ala enantiomers did not show any difference in stability. These results were consistent with a preferred cis coordination of the amino group of the ligand and of the amino acid in the ternary complexes (“cis effect”), which leads to the inclusion of the aromatic side chain of D-Trp, but not of that of L-Trp. In Trp-containing ternary complexes, the two enantiomers showed differences in the fluorescence lifetime distribution, consistent with only one conformer of D-Trp and two conformers of L-Trp, and the latter were found to be more accessible to fluorescence quenching by acrylamide and KI. Chirality 9:341–349, 1997. © 1997 Wiley-Liss, Inc. 相似文献
102.
Mónica Díaz-Coránguez José Segovia Adolfo López-Ornelas Henry Puerta-Guardo Juan Ludert Bibiana Chávez Noemi Meraz-Cruz Lorenza González-Mariscal 《PloS one》2013,8(4)
Transit of human neural stem cells, ReNcell CX, through the blood brain barrier (BBB) was
evaluated in an in vitro model of BBB and in nude mice. The BBB model was based on
rat brain microvascular endothelial cells (RBMECs) cultured on Millicell inserts bathed from the
basolateral side with conditioned media (CM) from astrocytes or glioma C6 cells. Glioma C6 CM
induced a significant transendothelial migration of ReNcells CX in comparison to astrocyte CM. The
presence in glioma C6 CM of high amounts of HGF, VEGF, zonulin and PGE2, together with
the low abundance of EGF, promoted ReNcells CX transmigration. In contrast cytokines IFN-α, TNF-α,
IL-12p70, IL-1β, IL-6, IL-8 and IL-10, as well as metalloproteinases -2 and -9 were present in equal
amounts in glioma C6 and astrocyte CMs. ReNcells expressed the tight junction proteins occludin and
claudins 1, 3 and 4, and the cell adhesion molecule CRTAM, while RBMECs expressed occludin, claudins
1 and 5 and CRTAM. Competing CRTAM mediated adhesion with soluble CRTAM, inhibited ReNcells CX
transmigration, and at the sites of transmigration, the expression of occludin and claudin-5
diminished in RBMECs. In nude mice we found that ReNcells CX injected into systemic circulation
passed the BBB and reached intracranial gliomas, which overexpressed HGF, VEGF and
zonulin/prehaptoglobin 2. 相似文献
103.
Expression of the HSP 70 gene family in rat hepatoma cell lines of different growth rates 总被引:2,自引:0,他引:2
Luisa Schiaffonati Carmela Pappalardo Lorenza Tacchini 《Experimental cell research》1991,196(2):330-336
We have studied the expression of different members of the HSP 70 gene family in MH1C1, FAO, and 3924A hepatoma cell lines, which possess different growth rates and show different levels of histone H3 gene expression. The cells have been subjected to mild (42 degrees C/1 h) or severe (45 degrees C/25 min) heat shock that causes a decrease in cell proliferation and histone H3 gene expression correlated to the severity of stress: previous mild heat shock protects against the effects of the subsequent severe exposure. All cell lines, irrespective of their growth rate, show a high constitutive expression of the HSC 73 gene, which is barely detectable in normal liver, and a good induction of the heat-inducible HSP 70 gene, which, however, seems to be induced less than in the normal tissue. The relative amount of grp 78 mRNA is high in all hepatoma cells lines, but only FAO cells maintain a significant expression of the albumin gene. The basic diversity in HSP 70 family gene expression between normal and tumors is still maintained in hepatoma cell lines, but the growth-related, quantitative differences among the transplantable hepatomas that we previously found in the animal (Bardella et al., Br. J. Cancer 55, 642-645, 1987; Cairo et al., Hepatology 9, 740-746, 1989), seem to be lost, or at least strongly blunted, in vitro. 相似文献
104.
Paladini Alessandra Catone Daniele O’Keeffe Patrick Toschi Francesco Suber Lorenza 《Plasmonics (Norwell, Mass.)》2018,13(5):1687-1693
Time-resolved polarization-dependent transient absorption has been used to study the plasmonicity of the optical transitions of Ag nanoparticles and nanoclusters. The lack of a measureable polarization anisotropy in the nanoparticles is indicative of the ultrafast electron-electron scattering while the anisotropy with a depolarization timescale of 500 fs observed in the nanoclusters indicates the excitation of a non-plasmonic state. The short lifetime of the anisotropy is a measure of electronic coupling between nearly degenerate states and is thus proposed as a sensitive measurement of the plasmonic content of the optical transitions of nanoclusters.
相似文献105.
Aleksandar Lj. Obradovic Navya Atluri Lorenza Dalla Massara Azra Oklopcic Nikola S. Todorovic Gaurav Katta Hari P. Osuru Vesna Jevtovic-Todorovic 《Molecular neurobiology》2018,55(1):164-172
Mounting evidence suggests that prolonged exposure to general anesthesia (GA) during brain synaptogenesis damages the immature neurons and results in long-term neurocognitive impairments. Importantly, synaptogenesis relies on timely axon pruning to select axons that participate in active neural circuit formation. This process is in part dependent on proper homeostasis of neurotrophic factors, in particular brain-derived neurotrophic factor (BDNF). We set out to examine how GA may modulate axon maintenance and pruning and focused on the role of BDNF. We exposed post-natal day (PND)7 mice to ketamine using a well-established dosing regimen known to induce significant developmental neurotoxicity. We performed morphometric analyses of the infrapyramidal bundle (IPB) since IPB is known to undergo intense developmental modeling and as such is commonly used as a well-established model of in vivo pruning in rodents. When IPB remodeling was followed from PND10 until PND65, we noted a delay in axonal pruning in ketamine-treated animals when compared to controls; this impairment coincided with ketamine-induced downregulation in BDNF protein expression and maturation suggesting two conclusions: a surge in BDNF protein expression “signals” intense IPB pruning in control animals and ketamine-induced downregulation of BDNF synthesis and maturation could contribute to impaired IPB pruning. We conclude that the combined effects on BDNF homeostasis and impaired axon pruning may in part explain ketamine-induced impairment of neuronal circuitry formation. 相似文献
106.
107.
Xiaohong R. Yang Melissa Rotunno Yanzi Xiao Christian Ingvar Hildur Helgadottir Lorenza Pastorino Remco van Doorn Hunter Bennett Cole Graham Joshua N. Sampson Michael Malasky Aurelie Vogt Bin Zhu Giovanna Bianchi-Scarra William Bruno Paola Queirolo Giuseppe Fornarini Johan Hansson Rainer Tuominen Laurie Burdett Belynda Hicks Amy Hutchinson Kristine Jones Meredith Yeager Stephen J. Chanock Maria Teresa Landi Veronica Höiom Håkan Olsson Nelleke Gruis Paola Ghiorzo Margaret A. Tucker Alisa M. Goldstein 《Human genetics》2016,135(11):1241-1249
108.
The CDKN2A/p16INK4a 5′UTR sequence and translational regulation: impact of novel variants predisposing to melanoma 下载免费PDF全文
Virginia Andreotti Alessandra Bisio Brigitte Bressac‐de Paillerets Mark Harland Odile Cabaret Julia Newton‐Bishop Lorenza Pastorino William Bruno Roberto Bertorelli Veronica De Sanctis Alessandro Provenzani Chiara Menin Gilberto Fronza Paola Queirolo Robert C. Spitale Giovanna Bianchi‐Scarrà Alberto Inga Paola Ghiorzo 《Pigment cell & melanoma research》2016,29(2):210-221
Many variants of uncertain functional significance in cancer susceptibility genes lie in regulatory regions, and clarifying their association with disease risk poses significant challenges. We studied 17 germline variants (nine of which were novel) in the CDKN2A 5′UTR with independent approaches, which included mono and bicistronic reporter assays, Western blot of endogenous protein, and allelic representation after polysomal profiling to investigate their impact on CDKN2A mRNA translation regulation. Two of the novel variants (c.‐27del23, c.‐93‐91delAGG) were classified as causal mutations (score ≥3), along with the c.‐21C>T, c.‐34G>T, and c.‐56G>T, which had already been studied by a subset of assays. The novel c.‐42T>A as well as the previously described c.‐67G>C were classified as potential mutations (score 1 or 2). The remaining variants (c.‐14C>T, c.‐20A>G, c.‐25C>T+c.‐180G>A, c.‐30G>A, c.‐40C>T, c.‐45G>A, c.‐59C>G, c.‐87T>A, c.‐252A>T) were classified as neutral (score 0). In conclusion, we found evidence that nearly half of the variants found in this region had a negative impact on CDKN2A mRNA translation, supporting the hypothesis that 5′UTR can act as a cellular Internal Ribosome Entry Site (IRES) to modulate p16INK4a translation. 相似文献
109.
110.
C. Lazzari D. Varjú 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,167(4):527-531
Summary
Triatoma bugs turn away from a vertical black stripe on the inner surface of a rotating or oscillating drum by keeping it in the lateral visual field at an angle relative to the long axis of the body. The value of depends on the angular velocity w of the drum. Below w=5° s–1, increases with increasing w, and the stripe can lie to either side of the animal. Occasionally, the bugs switch between these two tracking modes. Above w=5° s–1, remains nearly constant at about 120° and the stripe lags behind the animal. We call this lateral tracking. At velocities over 5° s–1 the animals track the leading edge of a wide black stripe in the same manner as they track a narrow stripe. Below 5° s–1 they walk towards the centre of the stripe (skototaxis). Objects moving towards the insect above the horizon are also fixated at an angle of about 120°. Lateral tracking is mediated mainly by the dorsal part of the visual field, as can be shown by occluding either the dorsal or ventral halves of the eyes. The walking speed of the bugs increases significantly during lateral tracking of an oscillating stripe compared with that during frontal fixation of a stationary one. We therefore interpret lateral tracking as an escape response. 相似文献