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The disorders of the central nervous system associated with cancer by remote immune-mediated mechanisms are a heterogeneous group. These disorders encompass the classic paraneoplastic disorders and the recently recognized autoimmune encephalitis associated with antibodies against neuronal cell surface or synaptic proteins that occur with or without cancer association. In the last decade, the new surge of interest in neuronal diseases associated with anti-neuronal antibodies led to the rapid discovery of new forms of disease that have different manifestations and were not previously suspected to be immune mediated. The recognition of these syndromes is important because it may lead to early detection of an underlying malignancy and prompt initiation of treatment, improving chances for a better outcome.  相似文献   
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The major toxicological concern associated with nanomaterials is the fact that some manufactured nanomaterials are redox active, and some particles transport across cell membranes, especially into mitochondria. Thus, evaluation of their toxicity upon acute exposure is essential. In this work, we evaluated the toxicity of silver nanoparticles (40 and 80 nm) and their effects in rat liver mitochondria bioenergetics.Wistar rat liver mitochondria demonstrate alterations in respiration and membrane potential capacities in the presence of either 40 or 80 nm silver nanoparticles. Our data demonstrated a statistically significant decrease in mitochondrial membrane potential, ADP-induced depolarization, and respiratory control ratio (RCR) upon exposure to silver nanoparticles.Our results show that silver nanoparticles cause impairment of mitochondrial function, due mainly to alterations of mitochondrial membrane permeability. This results in an uncoupling effect on the oxidative phosphorylation system. Thus, mitochondrial toxicity may have a central role in the toxicity resulting from exposure to silver nanoparticles.  相似文献   
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The present study investigated the similarities between rodent and human urothelial carcinogenesis models using DNA content, p53 and Ki-67 immunoexpression as surrogate markers of bladder carcinogenesis. Following N-butyl-N-(4-hydroxybutyl)-nitrosamine exposure, 49 human cystectomy specimens of bladder cancer and 53 rat bladder specimens were studied. All of the tumours and adjacent mucosa present in each specimen were evaluated. High similarities were observed between the rodent urothelium carcinogenesis process and the corresponding process in humans, in regards to the histopathological features and biological alteration profile: DNA aneuploidy, p53 overexpression and high proliferative index measured by Ki-67 immunoexpression. Despite these similarities, a higher frequency of alterations was observed in earlier stages in the rat chemical-induced carcinogenesis, namely in 5c aneuploid cells, p53 overexpression and higher Ki-67 labelling index. These results confirm that this experimental animal model is a suitable and reproducible model of bladder carcinogenesis, particularly in regards to high-risk non-invasive and invasive urothelial carcinomas. These features mandate its use in the identification of new molecular targets and evaluation of tumour response to new cytotoxic drugs or drug combinations in bladder cancer therapeutic intervention.  相似文献   
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Naturally occurring xanthones have been documented as having antitumor properties, with some of them presently undergoing clinical trials. In an attempt to improve the biological activities of dihydroxyxanthones, prenylation and other molecular modifications were performed. All the compounds reduced viable cell number in a leukemia cell line K-562, with the fused xanthone 3,4-dihydro-12-hydroxy-2,2-dimethyl-2H,6H-pyrano[3,2-b]xanthen-6-one (5) being the most potent. The pyranoxanthone 5 was particularly effective in additional leukemia cell lines (HL-60 and BV-173). Furthermore, the pyranoxanthone 5 decreased cellular proliferation and induced an S-phase cell cycle arrest. In vitro, the pyranoxanthone 5 increased the percentage of apoptotic cells which was confirmed by an appropriate response at the protein level (e.g., PARP cleavage). Using a computer screening strategy based on the structure of several anti- and pro-apoptotic proteins, it was verified that the pyranoxanthone 5 may block the binding of anti-apoptotic Bcl-xL to pro-apoptotic Bad and Bim. The structure-based screening revealed the pyranoxanthone 5 as a new scaffold that may guide the design of small molecules with better affinity profile for Bcl-xL.  相似文献   
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The goal of this investigation was to determine whether chenodeoxycholic acid (CDCA)-induced apoptosis is prevented by ursodeoxycholic acid (UDCA) or tauroursodeoxycholic acid (TUDC) and to characterize the involvement of mitochondria in the process. Cultured human HepG2 cells were treated in a dose- and time-dependent protocol in order to establish a sufficiently low exposure to CDCA that causes apoptosis but not necrosis. Low-dose CDCA induced an S-phase block and G2 arrest of the cell cycle, as determined by flow cytometry. As a result, cell proliferation was inhibited. CDCA-induced apoptosis, as determined by fluorescence microscopy of Hoechst 33342-stained nuclei, was evident upon coincubation with TUDC. Additionally, after exposure to UDCA plus CDCA, the cell membrane was permeable to fluorescent dyes. Caspase-9-like activity, poly(ADP-ribose) polymerase (PARP) cleavage, and extensive DNA fragmentation were detected in CDCA-exposed cells and in cells coincubated with TUDC, but not UDCA. CDCA caused a decrease in mitochondrial membrane potential and depletion of ATP, both of which were potentiated by UDCA but not TUDC. The results suggest that UDCA potentiates CDCA cytotoxicity, probably at the level of induction of the mitochondrial permeability transition (MPT). Consequently, as suggested by the lack of the main hallmarks of the apoptotic pathway, in the presence of UDCA, CDCA-induced apoptosis is not properly executed but degenerates into necrosis.  相似文献   
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