969 resultados para doxorubicin derivative


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The present dataset contains the source data for Figure 2B of Tentner et al. (2012). The data shows the percentage of cultured cell-populations that stained positively and/or negatively for apoptotic markers cleaved caspase-3 and cleaved PARP, following DNA damage treatments induced by various doses of doxorubicin (0, 2 and 10 µmole/L) in the presence (100 ng/mL) or absence (0 ng/mL) of TNF-alpha co-treatment. For the six treatment conditions investigated, cell counts were made by flow cytometry at times 6, 12, 24, and 48 h following treatment; CULTURE DETAILS: U2OS cells were obtained from ATCC were maintained at 21% oxygen and 5% CO2 in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum, penicillin, streptomycin, 2mM L-glutamine, and used within 15-20 passages. The first thymidine block was released by washing the plates three times with PBS, and incubating them in fresh thymidine-free media for 12 h. A second thymidine block was then performed by re-addition of thymidine to 2.5 mM followed by incubation for an additional 18 h. Media was aspirated, plates were washed 3 with PBS, and replaced with fresh media in the presence or absence of 10 mM aphidicolin; ANALYSIS DETAILS: See supplementary journal publication; RESULT: The authors of the supplementary journal publication conclude that TNF enhances dose-dependent cell death following doxorubicin-induced DNA damage with minimal affect on dose-dependent cell-cycle arrest.

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We present a technique to reconstruct the electromagnetic properties of a medium or a set of objects buried inside it from boundary measurements when applying electric currents through a set of electrodes. The electromagnetic parameters may be recovered by means of a gradient method without a priori information on the background. The shape, location and size of objects, when present, are determined by a topological derivative-based iterative procedure. The combination of both strategies allows improved reconstructions of the objects and their properties, assuming a known background.

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The first derivative of spectral reflectance of tomatoes was studied to see whether it can detect molds and sunscald damage on the fruit. The results indicate that a quality index based on the derivative values of reflectance at 590- and 710-nm wavelengths can be used to separate good tomates from those with black mold, gray mold, and sunscald.

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Four-dimensional flow in the phase space of three amplitudes of circularly polarized Alfven waves and one relative phase, resulting from a resonant three-wave truncation of the derivative nonlinear Schrödinger equation, has been analyzed; wave 1 is linearly unstable with growth rate , and waves 2 and 3 are stable with damping 2 and 3, respectively. The dependence of gross dynamical features on the damping model as characterized by the relation between damping and wave-vector ratios, 2 /3, k2 /k3, and the polarization of the waves, is discussed; two damping models, Landau k and resistive k2, are studied in depth. Very complex dynamics, such as multiple blue sky catastrophes and chaotic attractors arising from Feigenbaum sequences, and explosive bifurcations involving Intermittency-I chaos, are shown to be associated with the existence and loss of stability of certain fixed point P of the flow. Independently of the damping model, P may only exist as against flow contraction just requiring.In the case of right-hand RH polarization, point P may exist for all models other than Landau damping; for the resistive model, P may exist for RH polarization only if 2+3/2.

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In previous papers, the type-I intermittent phenomenon with continuous reinjection probability density (RPD) has been extensively studied. However, in this paper type-I intermittency considering discontinuous RPD function in one-dimensional maps is analyzed. To carry out the present study the analytic approximation presented by del Río and Elaskar (Int. J. Bifurc. Chaos 20:1185-1191, 2010) and Elaskar et al. (Physica A. 390:2759-2768, 2011) is extended to consider discontinuous RPD functions. The results of this analysis show that the characteristic relation only depends on the position of the lower bound of reinjection (LBR), therefore for the LBR below the tangent point the relation {Mathematical expression}, where {Mathematical expression} is the control parameter, remains robust regardless the form of the RPD, although the average of the laminar phases {Mathematical expression} can change. Finally, the study of discontinuous RPD for type-I intermittency which occurs in a three-wave truncation model for the derivative nonlinear Schrodinger equation is presented. In all tests the theoretical results properly verify the numerical data

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We present a compact formula for the derivative of a 3-D rotation matrix with respect to its exponential coordinates. A geometric interpretation of the resulting expression is provided, as well as its agreement with other less-compact but better-known formulas. To the best of our knowledge, this simpler formula does not appear anywhere in the literature. We hope by providing this more compact expression to alleviate the common pressure to reluctantly resort to alternative representations in various computational applications simply as a means to avoid the complexity of differential analysis in exponential coordinates.

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The only treatment of patients with acute ischemic stroke is thrombolytic therapy, which benefits only a fraction of stroke patients. Both human and experimental studies indicate that ischemic stroke involves secondary inflammation that significantly contributes to the outcome after ischemic insult. Minocycline is a semisynthetic second-generation tetracycline that exerts antiinflammatory effects that are completely separate from its antimicrobial action. Because tetracycline treatment is clinically well tolerated, we investigated whether minocycline protects against focal brain ischemia with a wide therapeutic window. Using a rat model of transient middle cerebral artery occlusion, we show that daily treatment with minocycline reduces cortical infarction volume by 76 ± 22% when the treatment is started 12 h before ischemia and by 63 ± 35% when started even 4 h after the onset of ischemia. The treatment inhibits morphological activation of microglia in the area adjacent to the infarction, inhibits induction of IL-1β-converting enzyme, and reduces cyclooxygenase-2 expression and prostaglandin E2 production. Minocycline had no effect on astrogliosis or spreading depression, a wave of ionic transients thought to contribute to enlargement of cortical infarction. Treatment with minocycline may act directly on brain cells, because cultured primary neurons were also salvaged from glutamate toxicity. Minocycline may represent a prototype of an antiinflammatory compound that provides protection against ischemic stroke and has a clinically relevant therapeutic window.

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The signal transducer and activator of transcription (STAT) 3, a transcriptional factor downstream of several cytokines, is activated by Janus kinase families and plays a pivotal role in cardiac hypertrophy through gp130. To determine the physiological significance of STAT3 in vivo, transgenic mice with cardiac-specific overexpression of the Stat3 gene (STAT3-TG) were generated. STAT3-TG manifested myocardial hypertrophy at 12 wk of age with increased expression of the atrial natriuretic factor (ANF), β-myosin heavy chain (MHC), and cardiotrophin (CT)-1 genes. The animals were injected i.p. with 15 mg/kg doxorubicin (Dox), an antineoplastic drug with restricted use because of its cardiotoxicity. The survival rates after 10 days were 25% (5/20) for control littermates (WT), but 80% (16/20) for STAT3-TG (P < 0.01). WT showed increased expression of β-MHC and ANF mRNAs in the hearts 1 day after Dox treatment; this expression peaked at 3 days, suggesting that the WT suffered from congestive heart failure. Although the expression of these mRNAs was elevated in STAT3-TG hearts before Dox treatment, no additional increase was observed after the treatment. Dox administration significantly reduced the expression of the cardiac α-actin and Stat3 genes in WT hearts but not in STAT3-TG. These results provide direct evidence that STAT3 transduces not only a hypertrophic signal but also a protective signal against Dox-induced cardiomyopathy by inhibiting reduction of cardiac contractile genes and inducing cardiac protective factors.

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Caspases are key mediators in liver inflammation and apoptosis. In the present study we provide evidence that a nitric oxide (NO) derivative of ursodeoxycholic acid (UDCA), NCX-1000 ([2-(acetyloxy)benzoic acid 3-(nitrooxymethyl)phenyl ester]), protects against liver damage in murine models of autoimmune hepatitis induced by i.v. injection of Con A or a Fas agonistic antibody, Jo2. Con A administration causes CD4+ T lymphocytes to accumulate in the liver and up-regulates FasL expression, resulting in FasL-mediated cytotoxicity. Cotreating mice with NCX-1000, but not with UDCA, protected against liver damage induced by Con A and Jo2, inhibited IL-1β, IL-18, and IFN-γ release and caspase 3, 8, and 9 activation. Studies on HepG2 cells demonstrated that NCX-1000, but not UDCA, directly prevented multiple caspase activation induced by Jo2. Incubating HepG2 cells with NCX-1000 resulted in intracellular NO formation and a DTT-reversible inhibition of proapoptotic caspases, suggesting that cysteine S-nitrosylation was the main mechanism responsible for caspase inhibition. Collectively, these data suggest that NCX-1000 protects against T helper 1-mediated liver injury by inhibiting both the proapoptotic and the proinflammatory branches of the caspase superfamily.

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There is increasing evidence that sphingolipid- and cholesterol-rich microdomains (rafts) exist in the plasma membrane. Specific proteins assemble in these membrane domains and play a role in signal transduction and many other cellular events. Cholesterol depletion causes disassembly of the raft-associated proteins, suggesting an essential role of cholesterol in the structural maintenance and function of rafts. However, no tool has been available for the detection and monitoring of raft cholesterol in living cells. Here we show that a protease-nicked and biotinylated derivative (BCθ) of perfringolysin O (θ-toxin) binds selectively to cholesterol-rich microdomains of intact cells, the domains that fulfill the criteria of rafts. We fractionated the homogenates of nontreated and Triton X-100-treated platelets after incubation with BCθ on a sucrose gradient. BCθ was predominantly localized in the floating low-density fractions (FLDF) where cholesterol, sphingomyelin, and Src family kinases are enriched. Immunoelectron microscopy demonstrated that BCθ binds to a subpopulation of vesicles in FLDF. Depletion of 35% cholesterol from platelets with cyclodextrin, which accompanied 76% reduction in cholesterol from FLDF, almost completely abolished BCθ binding to FLDF. The staining patterns of BCθ and filipin in human epidermoid carcinoma A431 cells with and without cholesterol depletion suggest that BCθ binds to specific membrane domains on the cell surface, whereas filipin binding is indiscriminate to cell cholesterol. Furthermore, BCθ binding does not cause any damage to cell membranes, indicating that BCθ is a useful probe for the detection of membrane rafts in living cells.

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Portal hypertension resulting from increased intrahepatic resistance is a common complication of chronic liver diseases and a leading cause of death in patients with liver cirrhosis, a scarring process of the liver that includes components of both increased fibrogenesis and wound contraction. A reduced production of nitric oxide (NO) resulting from an impaired enzymatic function of endothelial NO synthase and an increased contraction of hepatic stellate cells (HSCs) have been demonstrated to contribute to high intrahepatic resistance in the cirrhotic liver. 2-(Acetyloxy) benzoic acid 3-(nitrooxymethyl) phenyl ester (NCX-1000) is a chemical entity obtained by adding an NO-releasing moiety to ursodeoxycholic acid (UDCA), a compound that is selectively metabolized by hepatocytes. In this study we have examined the effect of NCX-1000 and UDCA on liver fibrosis and portal hypertension induced by i.p. injection of carbon tetrachloride in rats. Our results demonstrated that although both treatments reduced liver collagen deposition, NCX-1000, but not UDCA, prevented ascite formation and reduced intrahepatic resistance in carbon tetrachloride-treated rats as measured by assessing portal perfusion pressure. In contrast to UDCA, NCX-1000 inhibited HSC contraction and exerted a relaxing effect similar to the NO donor S-nitroso-N-acetylpenicillamine. HSCs were able to metabolize NCX-1000 and release nitrite/nitrate in cell supernatants. In aggregate these data indicate that NCX-1000, releasing NO into the liver microcirculation, may provide a novel therapy for the treatment of patients with portal hypertension.

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The relationship of the important cellulase producing asexual fungus Trichoderma reesei to its putative teleomorphic (sexual) ancestor Hypocrea jecorina and other species of the Trichoderma sect. Longibrachiatum was studied by PCR-fingerprinting and sequence analyses of the nuclear ribosomal DNA region containing the internal transcribed spacers (ITS-1 and ITS-2) and the 5.8S rRNA gene. The differences in the corresponding ITS sequences allowed a grouping of anamorphic (asexual) species of Trichoderma sect. Longibrachiatum into Trichoderma longibrachiatum, Trichoderma pseudokoningii, and Trichoderma reesei. The sexual species Hypocrea schweinitzii and H. jecorina were also clearly separated from each other. H. jecorina and T. reesei exhibited identical sequences, suggesting close relatedness or even species identity. Intraspecific and interspecific variation in the PCR-fingerprinting patterns supported the differentiation of species based on ITS sequences, the grouping of the strains, and the assignment of these strains to individual species. The variations between T. reesei and H. jecorina were at the same order of magnitude as found between all strains of H. jecorina, but much lower than the observed interspecific variations. Identical ITS sequences and the high similarity of PCR-fingerprinting patterns indicate a very close relationship between T. reesei and H. jecorina, whereas differences of the ITS sequences and the PCR-fingerprinting patterns show a clear phylogenetic distance between T. reesei/H. jecorina and T. longibrachiatum. T. reesei is considered to be an asexual, clonal line derived from a population of the tropical ascomycete H. jecorina.

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Upon stimulation with anti-CD3, suppressor T-cell (Ts) hybridomas and homologous transfectants of T-cell receptor a (TCRalpha) cDNA in the T-cell hybridoma formed a 55-kDa TCRalpha chain derivative that bound both the monoclonal anti-TCRalpha chain and polyclonal antibodies against glycosylation inhibiting factor (GIF). The peptide is a subunit of antigen-specific suppressor T-cell factor (TsF), and is considered to be a posttranslationally-formed conjugate of TCRalpha chain with GIF peptide. The TCRalpha derivative is synthesized by the transfectant after stimulation with anti-CD3, and not derived from TCR present on the cell surface. Stimulation of the stable homologous transfectants with anti-CD3 induced translocation of the 13-kDa GIF peptide into endoplasmic reticulum (ER). When a helper Ts hybridoma or a stable transfectant of the same TCRalpha cDNA in a helper cell-derived TCRalpha- clone was stimulated with anti-CD3, translocation of GIF peptide was not detected, and these cells failed to secrete a TCRalpha derivative. However, further transfection of a chimeric cDNA encoding a procalcitonin-GIF fusion protein into the helper cell-derived stable transfectant of TCRalpha cDNA resulted in translocation of the GIF protein and formation of bioactive 55-kDa GIF. The results indicated that translocation of GIF peptide through ER is unique for Ts cells, and that this process is essential for the formation/secretion of the soluble form derivative of TCRalpha chain by T cells.

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Overactivation of calcium-activated neutral protease (calpain) has been implicated in the pathophysiology of several degenerative conditions, including stroke, myocardial ischemia, neuromuscular degeneration, and cataract formation. Alpha-mercaptoacrylate derivatives (exemplified by PD150606), with potent and selective inhibitory actions against calpain, have been identified. PD150606 exhibits the following characteristics: (i) Ki values for mu- and m-calpains of 0.21 microM and 0.37 microM, respectively, (ii) high specificity for calpains relative to other proteases, (iii) uncompetitive inhibition with respect to substrate, and (iv) it does not shield calpain against inactivation by the active-site inhibitor trans-(epoxysuccinyl)-L-leucyl-amido-3-methylbutane, suggesting a nonactive site action for PD150606. The recombinant calcium-binding domain from each of the large or small subunits of mu-calpain was found to interact with PD150606. In low micromolar range, PD15O6O6 inhibited calpain activity in two intact cell systems. The neuroprotective effects of this class of compound were also demonstrated by the ability of PD150606 to attenuate hypoxic/hypoglycemic injury to cerebrocortical neurons in culture and excitotoxic injury to Purkinje cells in cerebellar slices.

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A convenient, high yield conversion of doxorubicin to 3'-deamino-3'-(2''-pyrroline-1''-yl)doxorubicin is described. This daunosamine-modified analog of doxorubicin is 500-1000 times more active in vitro than doxorubicin. The conversion is effected by using a 30-fold excess of 4-iodobutyraldehyde in anhydrous dimethylformamide. The yield is higher than 85%. A homolog of this compound, 3'-deamino-3'-(1'',3''-tetrahydropyridine-1''-yl)doxorubicin, was also synthesized by using 5-iodovaleraldehyde. In this homolog, the daunosamine nitrogen is incorporated into a six- instead of a five-membered ring. This analog was 30-50 times less active than its counterpart with a five-membered ring. A similar structure-activity relationship was found when 3'-deamino-3'-(3''-pyrrolidone-1''-yl)doxorubicin (containing a five-membered ring) and 3'-deamino-3'-(3''-piperidone-1''-yl)doxorubicin (with a six-membered ring) were tested in vitro, the former being 5 times more potent than the latter. To further elucidate structure-activity relationships, 3'-deamino-3'-(pyrrolidine-1''-yl)doxorubicin, 3'-deamino-3'-(isoindoline-2''-yl)doxorubicin, 3'-deamino-3'-(2''-methyl-2''-pyrroline-1''-yl)doxorubicin, and 3'-deamino-3'-(3''-pyrroline-1''-yl)doxorubicin were also synthesized and tested. All the analogs were prepared by using reactive halogen compounds for incorporating the daunosamine nitrogen of doxorubicin into a five- or six-membered ring. These highly active antineoplastic agents can be used for incorporation into targeted cytotoxic analogs of luteinizing hormone-releasing hormone intended for cancer therapy.