Home About us Contact
|
Home About us Contact | ||
|
|
||
Rb
Terms modified by Rb Selected AbstractsDynamic assembly of chromatin complexes during cellular senescence: implications for the growth arrest of human melanocytic neviAGING CELL, Issue 4 2007Debdutta Bandyopadhyay Summary The retinoblastoma (RB)/p16INK4a pathway regulates senescence of human melanocytes in culture and oncogene-induced senescence of melanocytic nevi in vivo. This senescence response is likely due to chromatin modifications because RB complexes from senescent melanocytes contain increased levels of histone deacetylase (HDAC) activity and tethered HDAC1. Here we show that HDAC1 is prominently detected in p16INK4a -positive, senescent intradermal melanocytic nevi but not in proliferating, recurrent nevus cells that localize to the epidermal/dermal junction. To assess the role of HDAC1 in the senescence of melanocytes and nevi, we used tetracycline-based inducible expression systems in cultured melanocytic cells. We found that HDAC1 drives a sequential and cooperative activity of chromatin remodeling effectors, including transient recruitment of Brahma (Brm1) into RB/HDAC1 mega-complexes, formation of heterochromatin protein 1, (HP1,)/SUV39H1 foci, methylation of H3-K9, stable association of RB with chromatin and significant global heterochromatinization. These chromatin changes coincide with expression of typical markers of senescence, including the senescent-associated ,-galactosidase marker. Notably, formation of RB/HP1, foci and early tethering of RB to chromatin depends on intact Brm1 ATPase activity. As cells reached senescence, ejection of Brm1 from chromatin coincided with its dissociation from HP1,/RB and relocalization to protein complexes of lower molecular weight. These results provide new insights into the role of the RB pathway in regulating cellular senescence and implicate HDAC1 as a likely mediator of early chromatin remodeling events. [source] Origin, age and petrogenesis of Neoproterozoic composite dikes from the Arabian-Nubian Shield, SW JordanGEOLOGICAL JOURNAL, Issue 2 2004G. Jarrar Abstract The evolution of a Pan-African (c. 900,550,Ma) suite of composite dikes, with latite margins and rhyolite interiors, from southwest Jordan is discussed. The dikes cut the Neoproterozoic calc-alkaline granitoids and high-grade metamorphic rocks (c. 800,600,Ma) of the northern Arabian-Nubian Shield in Jordan and have been dated by the Rb-Sr isochron method at 566±7,Ma. The symmetrically distributed latite margins constitute less than one-quarter of the whole dike thickness. The rhyolite intruded a median fracture within the latite, while the latter was still hot but completely solidified. The dikes are alkaline and bimodal in composition with a gap in SiO2 between 61 and 74,wt%. Both end members display similar chondrite-normalized rare earth element patterns. The rhyolites display the compositional signature of A-type granites. The (La/Lu)N values are 6.02 and 4.91 for latites and rhyolites, respectively, and the rhyolites show a pronounced negative Eu anomaly, in contrast to the slight negative Eu anomaly of the latites. The chemical variability (e.g. Zr/Y, Zr/Nb, K/Rb) within and between latites and rhyolites does not support a fractional crystallization relationship between the felsic and mafic members of the dikes. We interpret the magma genesis of the composite dikes as the result of intrusion of mantle-derived mafic magma into the lower crust in an extensional tectonic regime. The mafic magma underwent extensive fractional crystallization, which supplied the necessary heat for melting of the lower crust. The products of the initial stages of partial melting (5,10%) mixed with the fractionating mafic magma and gave rise to the latite melts. Further partial melting of the lower crust (up to 30%) produced a felsic melt, which upon 50% fractional crystallization (hornblende 15%, biotite 5%, feldspars 60%, and quartz 20%) gave rise to the rhyolitic magma. Copyright © 2004 John Wiley & Sons, Ltd. [source] Bayesian Networks and Adaptive Management of Wildlife HabitatCONSERVATION BIOLOGY, Issue 4 2010ALISON L. HOWES herramientas para la toma de decisiones; incertidumbre ecológica; pastoreo feral; regímenes de quema; validación de modelos Abstract:,Adaptive management is an iterative process of gathering new knowledge regarding a system's behavior and monitoring the ecological consequences of management actions to improve management decisions. Although the concept originated in the 1970s, it is rarely actively incorporated into ecological restoration. Bayesian networks (BNs) are emerging as efficient ecological decision-support tools well suited to adaptive management, but examples of their application in this capacity are few. We developed a BN within an adaptive-management framework that focuses on managing the effects of feral grazing and prescribed burning regimes on avian diversity within woodlands of subtropical eastern Australia. We constructed the BN with baseline data to predict bird abundance as a function of habitat structure, grazing pressure, and prescribed burning. Results of sensitivity analyses suggested that grazing pressure increased the abundance of aggressive honeyeaters, which in turn had a strong negative effect on small passerines. Management interventions to reduce pressure of feral grazing and prescribed burning were then conducted, after which we collected a second set of field data to test the response of small passerines to these measures. We used these data, which incorporated ecological changes that may have resulted from the management interventions, to validate and update the BN. The network predictions of small passerine abundance under the new habitat and management conditions were very accurate. The updated BN concluded the first iteration of adaptive management and will be used in planning the next round of management interventions. The unique belief-updating feature of BNs provides land managers with the flexibility to predict outcomes and evaluate the effectiveness of management interventions. Resumen:,El manejo adaptativo es un proceso interactivo de recopilación de conocimiento nuevo relacionado con el comportamiento de un sistema y el monitoreo de las consecuencias ecológicas de las acciones de manejo para refinar las opciones de manejo. Aunque el concepto se originó en la década de los 1970s, rara vez es incorporado activamente en la restauración ecológica. Las redes Bayesianas (RBs) están emergiendo como herramientas eficientes para la toma de decisiones ecológicas en el contexto del manejo adaptativo, pero los ejemplos de su aplicación en este sentido son escasos. Desarrollamos una RB en el marco del manejo adaptativo que se centra en el manejo de los efectos del pastoreo feral y los regímenes de quemas prescritas sobre la diversidad de aves en bosques subtropicales del este de Australia. Construimos la RB con datos para predecir la abundancia de aves como una función de la estructura del hábitat, la presión de pastoreo y las quemas prescritas. Los resultados del análisis de sensibilidad sugieren que la presión de pastoreo incrementó la abundancia de melífagos agresivos, que a su vez tuvieron un fuerte efecto negativo sobre paserinos pequeños. Posteriormente se llevaron a cabo intervenciones de manejo para reducir la presión del pastoreo feral y quemas prescritas, después de las cuales recolectamos un segundo conjunto de datos de campo para probar la respuesta de paserinos pequeños a estas medidas. Utilizamos estos datos, que incorporaron cambios ecológicos que pueden haber resultado de la intervención de manejo, para validar y actualizar la RB. Las predicciones de la abundancia de paserinos pequeños bajo las nuevas condiciones de hábitat y manejo fueron muy precisas. La RB actualizada concluyó la primera iteración de manejo adaptativo y será utilizada para la planificación de la siguiente ronda de intervenciones de manejo. La característica única de actualización de la RBs permite que los manejadores tengan flexibilidad para predecir los resultados y evaluar la efectividad de las intervenciones de manejo. [source] Crystal structure refinement of the ternary compound Cu2SnTe3 by X-ray powder diffractionCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2008G. E. Delgado Abstract The ternary compound Cu2SnTe3 crystallizes in the Imm2 (Nº 44) space group, Z = 2, with a = 12.833(4) Å, b = 4.274(1) Å, c = 6.043(1) Å, V = 331.5(1) Å3. Its structure was refined from X-ray powder diffraction data using the Rietveld method. The refinement of 25 instrumental and structural variables led to Rp = 10.2%, Rwp = 11.8%, Rexp = 7.7%, RB = 10.6%, S = 1.6 and ,2 = 2.6, for 5501 step intensities and 163 independent reflections. This compound is isostructural with Cu2GeSe3, and consists of a three-dimensional arrangement of slightly distorted CuTe4 and SnTe4 tetrahedra connected by common corners. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Transcriptional control of Rohon-Beard sensory neuron development at the neural plate borderDEVELOPMENTAL DYNAMICS, Issue 4 2009Christy Cortez Rossi Abstract Rohon-Beard (RB) mechanosensory neurons are among the first sensory neurons to develop, and the process by which they adopt their fate is not completely understood. RBs form at the neural plate border (NPB), the junction between neural and epidermal ectoderm, and require the transcription factor prdm1a. Here, we show that prior to RB differentiation, prdm1a overlaps extensively with the epidermal marker dlx3b but shows little overlap with the neuroectodermal markers sox3 and sox19a. Birthdating analysis reveals that the majority of RBs are born during gastrulation in zebrafish, suggesting that it is during this period that RBs become specified. Expression analysis in prdm1a and neurogenin1 mutant and dlx3b/dlx4b morpholino-injected embryos suggests that prdm1a is upstream of dlx3b, dlx4b, and neurogenin1 at the NPB. mRNA for neurogenin1 or dlx3b/dlx4b can rescue the lack of RBs in prdm1a mutants. Based on these data, we suggest a preliminary gene regulatory network for RB development. Developmental Dynamics 238:931,943, 2009. © 2009 Wiley-Liss, Inc. [source] Cytopathological diagnosis of adult retinoblastoma in a vitrectomy specimen,DIAGNOSTIC CYTOPATHOLOGY, Issue 1 2010Maria E. Orellana M.D. Abstract Retinoblastoma (RB) is extremely rare in adults. We describe a case of RB diagnosed by cytology in a vitrectomy specimen of a 23-year-old patient who presented with diminished visual acuity and retinal detachment in the absence of a clinically-visible mass. Cytological examination of the vitreous fluid showed clusters of loosely cohesive atypical cells with high nuclear to cytoplasmic ratio and "salt and pepper" chromatin pattern in a background of normal neuronal retinal cells. Nuclear molding was present as well as numerous apoptotic bodies. The cells were focally positive for epithelial markers and showed strong and diffuse positivity for neuroendocrine markers. Ki-67 stained 90% of the "atypical cells" nuclei, in contrast to nonneoplastic retinal neuronal cells, which were negative for the marker. A diagnosis of RB was rendered, and subsequently was confirmed in the enucleation specimen. The cytological differential diagnosis is discussed as well as the role that cytology and immunohistochemistry can play in differentiating neoplastic cells from normal retinal cellular elements in vitreous fluid specimens. Diagn. Cytopathol. 2010. © 2009 Wiley-Liss, Inc. [source] Diagrammatic Separation of Different Crystal Structures of A2BX4 Compounds Without Energy Minimization: A Pseudopotential Orbital Radii ApproachADVANCED FUNCTIONAL MATERIALS, Issue 12 2010Xiuwen Zhang Abstract The A2BX4 family of compounds manifest a wide range of physical properties, including transparent conductivity, ferromagnetism, and superconductivity. A 98% successful diagrammatic separation of the 44 different crystal structures of 688 oxide A2BX4 compounds (96% for 266 oxide-only) is described by plotting the total radius of the A atom RA versus the radius of the B atom RB for many A2BX4 compounds of known structure types and seeking heuristically simple, straight boundaries in the RA versus RB plane that best separate the domains of different structure types. The radii are sums RA,=,Rs(A),+,Rp(A) of the quantum-mechanically calculated "orbital radii" Rs(Rp), rather than empirical radii or phenomenological electronegativity scales. These success rates using first-principles orbital radii uniformly exceed the success rates using classic radii. Such maps afford a quick guess of the crystal structure of a yet unmade A2BX4 compound by placing its atomic orbital radii on such maps and reading off its structure type. [source] Profiling genomic copy number changes in retinoblastoma beyond loss of RB1GENES, CHROMOSOMES AND CANCER, Issue 2 2007Ella Bowles Loss of both RB1 alleles is rate limiting for development of retinoblastoma (RB), but genomic copy number gain or loss may impact oncogene(s) and tumor suppressor genes, facilitating tumor progression. We used quantitative multiplex polymerase chain reaction to profile "hot spot" genomic copy number changes for gain at 1q32.1, 6p22, and MYCN, and loss at 16q22 in 87 primary RB and 7 cell lines. Loss at 16q22 (48%) negatively associated with MYCN gain (18%) (Fisher's exact P = 0.031), gain at 1q32.1 (62%) positively associated with 6p "hot spot" gain (43%) (P = 0.033), and there was a trend for positive association between 1q and MYCN gain (P = 0.095). Cell lines had a higher frequency of MYCN amplification than primary tumors (29% versus 3%; P= 0.043). Novel high-level amplification of 1q32.1 in one primary tumor, confirmed by fluorescence in situ hybridization, strongly supports the presence of oncogene(s) in this region, possibly the mitotic kinesin, KIF14. Gene-specific quantitative multiplex polymerase chain reaction of candidate oncogenes at 1q32.1 (KIF14), 6p22 (E2F3 and DEK), and tumor suppressor genes at 16q22 (CDH11) and 17q21 (NGFR) showed the most common gene gains in RB to be KIF14 in cell lines (80%) and E2F3 in primary tumors (70%). The patterns of gain/loss were qualitatively different in 25 RB compared with 12 primary hepatocellular carcinoma and 12 breast cancer cell lines. Gene specific analysis of one bone marrow metastasis of RB, prechemotherapy and postchemotherapy, showed the typical genomic changes of RB pretreatment, which normalized after chemotherapy. © 2006 Wiley-Liss, Inc. [source] Evaluating best evaporation estimate model for water surface evaporation in semi-arid region, IndiaHYDROLOGICAL PROCESSES, Issue 8 2008Shakir Ali Abstract Evaluating performances of four commonly used evaporation estimate methods, namely; Bowen ratio energy balance (BREB), mass transfer (MT), Priestley,Taylor (PT) and pan evaporation (PE), based on 4 years experimental data, the most effective and the reliable evaporation estimates model for the semi-arid region of India has been derived. The various goodness-of-fit measures, such as; coefficient of determination (R2), index of agreement (D), root mean square error (RMSE), and relative bias (RB) have been chosen for the performance evaluation. Of these models, the PT model has been found most promising when the Bowen ratio, , is known a priori, and based on its limited data requirement. The responses of the BREB, the PT, and the PE models were found comparable to each other, while the response of the MT model differed to match with the responses of the other three models. The coefficients, , of the BREB, µ of the MT, , of the PT and KP of the PE model were estimated as 0·07, 2·35, 1·31 and 0·65, respectively. The PT model can successfully be extended for free water surface evaporation estimates in semi-arid India. A linear regression model depicting relationship between daily air and water temperature has been developed using the observed water temperatures and the corresponding air temperatures. The model helped to generate unrecorded water temperatures for the corresponding ambient air temperatures. Copyright © 2007 John Wiley & Sons, Ltd. [source] Comparison of total tract digestibility, development of visceral organs and digestive tract of Mong cai and Yorkshire × Landrace piglets fed diets with different fibre sourcesJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 2 2009N. T. Len Summary The aim of the study was to evaluate the effects of piglet age and dietary fibre source on the development of visceral organs and the gastrointestinal tract (GIT), and on growth performance and total tract apparent digestibility (TTAD) in local [pure-breed Mong cai (MC)] and exotic [Landrace × Yorkshire (LY)] piglets. The experimental diets contained different fibre sources: C (basal diet), RB (basal diet + rice bran), SPVM (basal diet + sweet potato vine meal) and CReM (basal diet + cassava residue meal). The neutral detergent fibre (NDF) content in diet C and the fibrous diets was 8.8% and 17.1%,17.7% respectively (dry matter basis). Collection of faecal samples to determine TTAD was carried out for five consecutive days before the experiment was finished (63 days). The piglets were killed at the age of 10 days (before being given the same solid feed), 30 days (weaning, 20 days after solid feed introduced) and 63 days (33 days after being given the different fibrous diets) when the length of intestinal segments, weight of organs (liver, heart, kidneys) and empty weight of the GIT (stomach, small intestine, caecum and colon + rectum) were measured. As the age of animals increased, the relative weight of organs and the length of intestines (expressed on a mass-specific basis) decreased (p < 0.05), and the weight of GIT increased (p < 0.001). The piglets fed fibrous diets had heavier GIT than those fed diet C with the highest values in CReM (p < 0.05). The colon + rectum length was not significantly different among C, RB and SPVM, but was shorter than in CReM (p < 0.05). Coefficient of total tract apparent digestibility (CTTAD) of nutrients in the fibrous diets was lower than in C (p < 0.01). Average daily gain (ADG) and feed conversion ratio (FCR) in C, RB and CReM were not different and were better than in SPVM (p < 0.01). There were no significant differences in the weights of organs between the two breeds at day 10, 30 and 63 (p > 0.05). The weight and length of GIT were not significantly different between the two breeds at day 10 and day 30, but were greater for MC at day 63. The caecum and colon + rectum at 10 and 30 days were longer in MC than in LY (p < 0.001). The relative development of GIT post-weaning was higher than pre-weaning, the difference being most apparent in MC. As a result at 63 days, MC had heavier visceral organs and GIT, and longer intestines on fibrous diets than LY (p < 0.05). The MC at 63 days had higher CTTAD of organic matter, gross energy, crude fibre and NDF (p < 0.001) and ether extract and crude protein (p < 0.05), but lower ADG and poorer FCR than LY (p < 0.001). It can be concluded that the GIT of the MC piglets developed more rapidly than LY when they were introduced to solid feed, and that the difference was more marked on the fibrous diets and after weaning, which resulted in higher total tract digestibility of nutrients in MC compared with LY. Cassava residue meal was better digested than RB and SPVM, and supported higher live weight gains. [source] Observation of orientational disorder in the hexagonal stuffed tridymite Sr0.864Eu0.136Al2O4 by the maximum-entropy methodJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 5 2004H. Yamada The crystal structure of a strontium europium aluminate, Sr0.864Eu0.136Al2O4, with a novel hexagonal form was investigated by a combination of Rietveld analysis and the maximum-entropy method (MEM) with synchrotron X-ray powder diffraction data. The electron density image calculated by the MEM/Rietveld method revealed that the apical oxygen ion in the AlO4 tetrahedron has a broad distribution corresponding to an extraordinarily large atomic displacement parameter. This structure could be expressed by a split-atom model, with which the Rietveld refinement gave Rwp = 2.99% and RB = 4.16%. Subsequently, MEM-based pattern fitting (MPF) decreased the R factors to Rwp = 2.81% and RB = 2.34% and the electron density image clearly showed that the apical oxygen ions of the AlO4 tetrahedra are split over three sites around a threefold axis involving an elongated distribution of the residual O ions along the c axis. These results suggest that AlO4 tetrahedra in Sr0.864Eu0.136Al2O4 are orientationally disordered. [source] Assessment of Rhodamine B for labelling the plague reservoir Rattus rattus in MadagascarAFRICAN JOURNAL OF ECOLOGY, Issue 3 2010Soanandrasana Rahelinirina Abstract The black rat is the main plague reservoir in rural foci in Madagascar, inside the villages as well as in the cultivated areas around. We have evaluated the potentialities of mass-marking of rats, using baits containing Rhodamine B (RB) in order to get a tool to study the movements of rats and to understand the spread of plague. Laboratory experiments demonstrated that: (i) rats were more attracted by the rodent granules and peanut butter; (ii) incorporation of RB in baits did not reduce their appetence; (iii) RB lasted for 60 days in rat vibrissae and 180 days in rat hairs; and (iv) consumption of baits during a week was under the lethal dose. Field tests have been realized comparatively among 24 highland villages where plague is endemic, in different contexts: baits inside houses or around the village, baits with and without RB, rats captured 1, 2 and 3 months after the marking. No negative effect of the RB on population dynamics of rats or fleas on them was observed. The effectiveness of the marking was comparable between males and females. This technique of collective marking appears very valuable for monitoring rat movements in plague foci. Résumé Le rat noir est le principal réservoir de la peste dans les foyers ruraux de Madagascar, dans les villages comme dans les zones cultivées environnantes. Nous avons évalué les potentialités de marquage en masse de rats avec des appâts contenant de la Rhodamine B (RB) afin de disposer d'un outil pour étudier les déplacements des rats et de comprendre la dispersion de la peste. Les expériences en laboratoire ont montré que : (i) les rats étaient plus attirés par les granulés pour rongeurs et le beurre de cacahuète; (ii) l'adjonction de RB dans les appâts ne réduisait pas leur appétence; (iii) la RB persistait pendant 60 jours dans les vibrisses des rats, et 180 jours dans leurs poils; et (iv) la consommation des appâts pendant une semaine restait en dessous de la dose létale. Des tests sur le terrain dans 24 villages des hauts plateaux où la peste est endémique étaient réalisés dans différents contextes: appâts dans les maisons et autour des villages, appâts avec ou sans RB, rats capturés un, deux ou trois mois après le marquage. Aucun effet négatif de la RB sur la dynamique de population des rats ou des puces qui les parasitent n'a été observé. L'efficacité du marquage était comparable chez les mâles et les femelles. Cette technique de marquage collectif apparaît très intéressante pour suivre les déplacements des rats dans les foyers de peste. [source] Identification of genetic networks involved in the cell growth arrest and differentiation of a rat astrocyte cell line RCG-12,JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2007Ichiro Takasaki Abstract The purpose of the present study is to establish and characterize a conditionally immortalized astrocyte cell line and to clarify the genetic networks responsible for the cell growth arrest and differentiation. A conditionally immortalized astrocyte cell line, RCG-12, was established by infecting primary cultured rat cortical glia cells with a temperature-sensitive simian virus 40 large T-antigen. At a permissive temperature of 33°C, the large T-antigen was expressed and cells grew continuously. On the other hand, the down-regulation of T-antigen at a non-permissive temperature of 39°C led to growth arrest and differentiation. The cells expressed astrocyte-expressed genes such as glial fibrillary acidic protein. Interestingly, the differentiated condition induced by the non-permissive temperature significantly elevated the expression levels of several astrocyte-expressed genes. To identify the detailed mechanisms by which non-permissive temperature-induced cell growth arrest and differentiation, we performed high-density oligonucleotide microarray analysis and found that 556 out of 15,923 probe sets were differentially expressed 2.0-fold. A computational gene network analysis revealed that a genetic network containing up-regulated genes such as RB, NOTCH1, and CDKN1A was associated with the cellular growth and proliferation, and that a genetic network containing down-regulated genes such as MYC, CCNB1, and IGF1 was associated with the cell cycle. The established cell line RCG-12 retains some characteristics of astrocytes and should provide an excellent model for studies of astrocyte biology. The present results will also provide a basis for understanding the detailed molecular mechanisms of the growth arrest and differentiation of astrocytes. J. Cell. Biochem. 102: 1472,1485, 2007. © 2007 Wiley-Liss, Inc. [source] Capacity of activated carbon derived from pistachio shells by H3PO4 in the removal of dyes and phenolicsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2003Amina A Attia Abstract Two activated carbons were obtained from pistachio shells by impregnation with H3PO4 under standard conditions of acid concentration (50 wt%) and heat treatment at 773 K for 2 h. The soaking time was 24 and 72 h for the two samples before thermal pyrolysis. Analysis of the N2/77 K adsorption isotherms proved that both were highly adsorbing carbons with considerable microporosity, and that the prolonged contact with activant enhanced total porosity (surface area and pore volume) and increased the amount of mesoporosity. Adsorption isotherms of probe molecules, viz methylene blue (MB), rhodamine B (RB), phenol (P) and p -nitrophenol (PNP), were determined at room temperature, from aqueous solutions. Both the Langmuir and Freundlich model adsorption equations show satisfactory fit to experimental data. Both carbons exhibit similar adsorption parameters irrespective of their porosity characteristics. The sequence of uptake per unit weight was: PNP > MB > RB > P. Low affinity towards phenol may be associated with its competition with water molecules which are more favourably attracted to the acid surface which has a high oxygen functionality. Preferred adsorption in the order PNP > MB > RB is proposed to be a function of carbon porosity, related to the increased molecular dimensions of the solutes. Adsorption from a binary mixture of equal concentrations of MB and RB showed reduced uptake for both sorbates in comparison to the single component experiments. RB removal surpasses that of MB in the binary test and may be attributed to lower water solubility and higher molecular dimensions. Copyright © 2003 Society of Chemical Industry [source] Dynamic assembly of chromatin complexes during cellular senescence: implications for the growth arrest of human melanocytic neviAGING CELL, Issue 4 2007Debdutta Bandyopadhyay Summary The retinoblastoma (RB)/p16INK4a pathway regulates senescence of human melanocytes in culture and oncogene-induced senescence of melanocytic nevi in vivo. This senescence response is likely due to chromatin modifications because RB complexes from senescent melanocytes contain increased levels of histone deacetylase (HDAC) activity and tethered HDAC1. Here we show that HDAC1 is prominently detected in p16INK4a -positive, senescent intradermal melanocytic nevi but not in proliferating, recurrent nevus cells that localize to the epidermal/dermal junction. To assess the role of HDAC1 in the senescence of melanocytes and nevi, we used tetracycline-based inducible expression systems in cultured melanocytic cells. We found that HDAC1 drives a sequential and cooperative activity of chromatin remodeling effectors, including transient recruitment of Brahma (Brm1) into RB/HDAC1 mega-complexes, formation of heterochromatin protein 1, (HP1,)/SUV39H1 foci, methylation of H3-K9, stable association of RB with chromatin and significant global heterochromatinization. These chromatin changes coincide with expression of typical markers of senescence, including the senescent-associated ,-galactosidase marker. Notably, formation of RB/HP1, foci and early tethering of RB to chromatin depends on intact Brm1 ATPase activity. As cells reached senescence, ejection of Brm1 from chromatin coincided with its dissociation from HP1,/RB and relocalization to protein complexes of lower molecular weight. These results provide new insights into the role of the RB pathway in regulating cellular senescence and implicate HDAC1 as a likely mediator of early chromatin remodeling events. [source] Invasive breast cancers detected by screening mammography: A detailed comparison of computer-aided detection-assisted single reading and double readingJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 5 2009JN Cawson Summary To compare double reading plus arbitration for discordance, (currently best practice, (BP)) with computer-aided-detection (CAD)-assisted single reading (CAD-R) for detection of invasive cancers detected within BreastScreen Australia. Secondarily, to examine characteristics of cancers detected/rejected using each method. Mammograms of 157 randomly selected double-read invasive cancers were mixed 1:9 with normal cancers (total 1569), all detected in a BreastScreen service. Cancers were detected by two readers or one reader (C2 and C1 cancers, ratio 70:30%) in the program. The 1569 film-screen mammograms were read by two radiologists (reader A (RA) and reader B(RB)), with findings recorded before and after CAD. Discordant findings with BP were resolved by arbitration. We compared CAD-assisted reading (CAD-RA, CAD-RB) with BP, and CAD and arbitration contribution to findings. We correlated cancer size, sensitivity and mammographic density with detection methods. BP sensitivity 90.4% compared with CAD-RA sensitivity 86.6% (P = 0.12) and CAD-RB 94.3% (P = 0.14). CAD-RB specificity was less than BP (P = 0.01). CAD sensitivity was 93%, but readers rejected most positive CAD prompts. After CAD, reader's sensitivity increased 1.9% and specificity dropped 0.2% and 0.8%. Arbitration decreased specificity 4.7%. Receiving operator curves analysis demonstrated BP accuracy better than CAD-RA, borderline significance (P = 0.07), but not CAD-RB. Secondarily, cancer size was similar for BP and CAD-R. Cancers recalled after arbitration (P = 0.01) and CAD-R (P = 0.10) were smaller. No difference in cancer size or sensitivity between reading methods was found with increasing breast density. CAD-R and BP sensitivity and cancer detection size were not significantly different. CAD-R specificity was significantly lower for one reader. [source] Intracellular and cell-free (infectious) HIV-1 in rectal mucosaJOURNAL OF MEDICAL VIROLOGY, Issue 4 2001Mariantonietta Di Stefano Abstract The intestinal mucosa contains most of the total lymphocyte pool and plays an important role in viral transmission, but only slight attention has been given to the immunological and virological aspects of human immunodeficiency virus-1 (HIV-1) infection at this site. In this study, before initiating or changing antiretroviral therapy, paired blood samples and rectal biopsies (RB) were obtained from 26 consecutive HIV-infected subjects. HIV-1 isolation and biological characterization, DNA, and HIV-1 RNA titration were assessed, as were in vitro tumor necrosis factor-alpha (TNF-,) and interleukin-, (IL-1,) spontaneous production. The rate of HIV-1 isolation from peripheral blood mononuclear cells (PBMCs) and RBs was 75% and 58%, respectively. All RB-derived isolates were nonsyncytium inducing (NSI), independent of the phenotype of blood-derived isolates. Proviral DNA and detectable HIV-1 RNA levels were measured in 100% and 77% of RBs, respectively. A statistical correlation was observed between HIV-1 DNA and HIV-1 RNA levels in rectal mucosa (P,=,0.0075), whereas no correlation was found between these levels in blood samples (P,>,0.05). Antiretroviral treatment did not seem to influence HIV-1 detection in RBs. Higher levels of in vitro proinflammmatory cytokine production were found in the RBs of most infected patients when compared with healthy controls. Therefore, the rectal mucosa is an important HIV-1 reservoir that demonstrates a discordant viral evolution with respect to blood. Both the virus type and the mucosa pathway of immunoactive substances might have important implications for therapeutic decision-making and monitoring and could influence the bidirectional transmission of HIV-1 in mucosal surfaces. J. Med. Virol. 65:637,643, 2001. © 2001 Wiley-Liss, Inc. [source] Acute treatment of paediatric migraine: A meta-analysis of efficacyJOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 1-2 2008Shawna Silver Aim: To undertake a meta-analysis of all randomised controlled trials (RCTs) on the acute pharmacologic treatment of children and adolescents with migraine headache. Methods: In total, 139 abstracts of clinical trials specific to the acute treatment of paediatric migraine were appraised. Inclusion criteria required clinical trials to be randomised, blinded, placebo-controlled studies with comparable endpoints. Non- English language publications were excluded. 11 clinical trials qualified for inclusion in the final meta-analysis. Two endpoints were analysed: the proportion of patients with (1) headache relief, and (2) complete pain relief, 2 h post-treatment. Results: The following medications were included in the analysis: acetaminophen (n = 1), ibuprofen (n = 2), sumatriptan (n = 5), zolmitriptan (n = 1), rizatriptan (n = 2) and dihydroergotamine (n = 1). Results are expressed as a relative benefit (RB) conferred over placebo and the number needed to treat (NNT). Only ibuprofen and sumatriptan provided a statistically significant relative efficacy in comparison with placebo. Two hours post-treatment, ibuprofen was associated with an RB 1.50 (95% CI 1.15,1.95) in the generation of headache relief (NNT 2.4) and RB 1.92 (95% CI 1.28,2.86) in the production of complete pain relief (NNT 4.9). Sumatriptan rendered an RB 1.26 (95% CI 1.13,1.41) in headache relief (NNT 7.4) and an RB 1.56 (95% CI 1.26,1.93) in the production of complete pain relief (NNT 6.9). Conclusion: Despite the pharmacological options for the management of acute migraine, few RCTs in the paediatric population exist. Composite data demonstrate that only ibuprofen and sumatriptan are significantly more effective than placebo in the generation of headache relief in children and adolescents. [source] Identification and determination of the saikosaponins in Radix bupleuri by accelerated solvent extraction combined with rapid-resolution LC-MSJOURNAL OF SEPARATION SCIENCE, JSS, Issue 13 2010Yun-Yun Yang Abstract A method based on accelerated solvent extraction combined with rapid-resolution LC,MS for efficient extraction, rapid separation, online identification and accurate determination of the saikosaponins (SSs) in Radix bupleuri (RB) was developed. The RB samples were extracted by accelerated solvent extraction using 70% aqueous ethanol v/v as solvent, at a temperature of 120°C and pressure of 100,bar, with 10,min of static extraction time and three extraction cycles. Rapid-resolution LC separation was performed by using a C18 column at gradient elution of water (containing 0.5% formic acid) and acetonitrile, and the major constituents were well separated within 20,min. A TOF-MS and an IT-MS were used for online identification of the major constituents, and 27 SSs were identified or tentatively identified. Five major bioactive SSs (SSa, SSc, SSd, 6,- O -acetyl-SSa and 6,- O -acetyl-SSd) with obvious peak areas and good resolution were chosen as benchmark substances, and a triple quadrupole MS operating in multiple-reaction monitoring mode was used for their quantitative analysis. A total of 16 RB samples from different regions of China were analyzed. The results indicated that the method was rapid, efficient, accurate and suitable for use in the quality control of RB. [source] The Efficacy of Acamprosate in the Maintenance of Abstinence in Alcohol-Dependent Individuals: Results of a Meta-AnalysisALCOHOLISM, Issue 1 2004Karl Mann Abstract: Background: A number of clinical trials have been undertaken to determine the efficacy of acamprosate in the maintenance of abstinence in alcohol-dependent individuals. However, the reported differences in patient populations, treatment duration, and study endpoints make comparisons difficult. An assessment of the efficacy of treatment with acamprosate was, therefore, undertaken using meta-analytical techniques. Methods: All randomized, placebo-controlled trials (RCTs) that fulfilled predetermined criteria were identified using (1) a language unrestricted search of 10 electronic databases; (2) a manual search of relevant journals, symposia, and conference proceedings; (3) cross-referencing of all identified publications; (4) personal communications with investigators; and (5) scrutiny of Merck-Santé's internal reports of all European trials. Study quality was assessed, independently, by three blinded workers. Key outcome data were identified; some outcome variables were recalculated to ensure consistency across trials. The primary outcome measure was continuous abstinence at 6 months; abstinence rates were determined by estimating Relative Benefit (RB). Results: A total of 19 published 1 unpublished RCTs were identified that fulfilled the selection criteria; 3 were excluded because the documentation available was insufficient to allow adequate assessment. The remaining 17 studies, which included 4087 individuals, 53% of whom received active drug, were of good quality and were otherwise reasonably comparable. There was no evidence of publication bias. Continuous abstinence rates at 6 months were significantly higher in the acamprosate-treated patients (acamprosate, 36.1%; placebo, 23.4%; RB, 1.47; [95% confidence intervals (CI): 1.29,1.69]; p < 0.001). This effect was observed independently of the method used for assigning missing data. The effect sizes in abstinent rates at 3, 6, and 12 months were 1.33, 1.50, and 1.95, respectively. At 12 months, the overall pooled difference in success rates between acamprosate and placebo was 13.3% (95% CI, 7.8,18.7%; number needed to treat, 7.5). Acamprosate also had a modest but significant beneficial effect on retention (6.01%; [95% CI, 2.90,8.82]; p= 0.0106). Conclusion:: Acamprosate has a significant beneficial effect in enhancing abstinence in recently detoxified, alcohol-dependent individuals. [source] Influence of heating conditions and starch on the storage modulus of Russet Burbank and Yukon Gold potatoesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2001Renan Bu-Contreras Abstract The storage modulus of Russet Burbank (RB) and Yukon Gold (YG) potato discs (13.3,mm,× 4.5,mm) was measured continuously during heating in water at temperatures ranging from 40 to 80,°C for 120,min using a dynamic mechanical analyser with a heating stage. The starch content of YG potatoes was higher than that of RB potatoes, but the raw starch granule size distribution of both varieties was similar. RB samples had the highest storage modulus values (25% higher than raw tissue) when heated in 60,°C water for 35,min. Image analysis revealed that the perimeters of starch granules in the potato samples increased by about 50% during heating for 30,min at 60,°C. Heating temperature and time and starch content influenced the storage modulus. © 2001 Society of Chemical Industry [source] Differences in molecular alterations of hepatocellular carcinoma between patients with a sustained virological response and those with hepatitis C virus infectionLIVER INTERNATIONAL, Issue 1 2009Takehiro Hayashi Abstract Background/Aims: The mechanism of hepatocarcinogenesis remains unclear in patients in whom hepatitis C virus (HCV) disappears after interferon (IFN) therapy. We compared molecular alterations in hepatocellular carcinoma (HCC) between patients with a sustained virological response (SVR) to IFN and patients with HCV. Methods: The study group comprised 44 patients with HCV and 13 patients with SVR. One patient in the SVR group had two tumour nodules, both of which were examined. Mitochondrial DNA (mtDNA) mutations in displacement-loop lesions were directly sequenced. Mutation of the TP53 gene was examined by direct sequencing. The methylation status of p16, p15, p14, RB and PTEN genes was evaluated by a methylation-specific polymerase chain reaction. Results: The average number of mtDNA mutations was 4.2 in 44 HCCs with HCV and 2.0 in 14 HCCs with SVR (P=0.0021). mtDNA mutation was less frequently detected in HCCs from patients with SVR than in patients with HCV. TP53 mutations were detected in 12 (27%) of 44 HCCs with HCV and 2 (14%) of 14 SVR-HCCs. Hypermethylation of the p16, p15, p14, RB and PTEN promoters was, respectively, detected in 34, 13, 8, 12 and 11 of 44 HCCs from patients with HCV and 14, 0, 0, 2 and 2 of 14 HCCs from patients with SVR (P=0.049, 0.021, 0.085, 0.322 and 0.402). Hypermethylation of p16 was one of the most important alterations in SVR-HCC. Conclusions: Molecular alterations in hepatocarcinogenesis of patients with SVR-HCC were different from those of patients with continuous HCV infection. [source] Health-related quality of life of food allergic patients measured with generic and disease-specific questionnairesALLERGY, Issue 8 2010B. M. J. Flokstra-de Blok To cite this article: Flokstra-de Blok BMJ, van der Velde JL, Vlieg-Boerstra BJ, Oude Elberink JNG, DunnGalvin A, Hourihane JO'B, Duiverman EJ, Dubois AEJ. Health-related quality of life of food allergic patients measured with generic and disease-specific questionnaires. Allergy 2010; 65: 1031,1038. Abstract Background:, Health-related quality of life (HRQL) has never been measured with both generic and disease-specific questionnaires in the same group of food allergic patients. The aim of this study was to compare HRQL of food allergic patients as measured with generic and disease-specific questionnaires. Methods:, Generic questionnaires (CHQ-CF87 and RAND-36) and disease-specific HRQL questionnaires (FAQLQ-CF, -TF and -AF) were completed by 79 children, 74 adolescents and 72 adults with food allergy. Floor and ceiling effects, percentage of agreement and multivariate stepwise regression analysis were used to compare the generic and disease-specific measurements. Results:, The Food Allergy Quality of Life Questionnaires (FAQLQs) showed minimal floor or ceiling effects. The CHQ-CF87 and RAND-36 showed minimal floor effects, but remarkable ceiling effects (>73%) were found for the scales role functioning-emotional (RE), role functioning-behaviour (RB), role functioning-physical (RP) in children and adolescents and the scale RE (>79%) in adults. Additionally, we found low percentages of agreement between the generic and disease-specific questionnaires to identify the same food allergic patients with the best or worst HRQL. Only patients with the best disease-specific HRQL also tended to have the best generic HRQL. Finally, the explained variance in HRQL by patient characteristics was higher in the disease-specific questionnaires (30.7,62.8%) than in the generic scales (6.7,31.7%). Conclusion:, Disease-specific HRQL questionnaires may be more suitable to measure clinically important impairments in HRQL or HRQL differences over time in food allergic patients. However, generic HRQL questionnaires are indispensable for the comparison between different diseases and are thus complementary. [source] Respiratory burst activity of polymorphonuclear cells is dependent on the cell preparation techniqueACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 6 2003J. Zhao Background: Controversial results have been reported regarding the effect of anaesthetics on superoxide anion production during the respiratory burst (RB) of polymorphonuclear cells (PMN). The differences could be caused by the cell preparation methods and the aim of this study was to compare two techniques. Methods: RB activity was measured in cell suspensions isolated with the single-step Ficoll procedure and in unfractionated whole blood. Two concentrations of propofol (therapeutic and 10-fold of this, 6 µg ml,1 or 60 µg ml,1) were investigated after cell preparation with both methods. RB was stimulated with Escherichia coli (E. coli), phorbol 12-myristate 13-acetate (PMA) or N-formyl-methionyl-leucyl-phenylalanine (fMLP) and measured by means of fluorescence intensity in a flow cytometer. Results: The percentage of PMNs in whole blood which generate superoxide anions in response to fMLP was significantly lower (2.5 ± 0.7%; mean ± SEM) than that in Ficoll isolated cell suspensions (15.1 ± 1.7%). Incubation with propofol led to a concentration-related decrease of RB activity in Ficoll separated PMNs after both PMA and fMLP stimulation. No significant effect of propofol was observed on the RB in PMA stimulated whole blood samples. Conclusion: The results suggest that the influence of cell preparation methods should be considered when the in vitro effects of anaesthetics on PMN functions are studied with flow cytometric methods. [source] Three temporal classes of gene expression during the Chlamydia trachomatis developmental cycleMOLECULAR MICROBIOLOGY, Issue 4 2000E. I. Shaw The obligate intracellular bacterium Chlamydia trachomatis has a unique developmental cycle that involves functionally and morphologically distinct cell types adapted for extracellular survival and intracellular multiplication. Infection is initiated by an environmentally resistant cell type called an elementary body (EB). Over the first several hours of infection, EBs differentiate into a larger replicative form, termed the reticulate body (RB). Late in the infectious process, RBs asynchronously begin to differentiate back to EBs, which accumulate within the lumen of the inclusion until released from the host cell for subsequent rounds of infection. In an effort to characterize temporal gene expression in relation to the chlamydial developmental cycle, we have used quantitative,competitive polymerase chain reaction (QC-PCR) and reverse transcription (RT)-PCR techniques. These analyses demonstrate that C. trachomatis double their DNA content every 2,3 h, with synthesis beginning between 2 and 4 h after infection. We determined the onset of transcription of specific temporal classes of developmentally expressed genes. RT-PCR analysis was performed on several genes encoding key enzymes or components of essential biochemical pathways and functions. This comparison encompassed approximately 8% of open reading frames on the C. trachomatis genome. In analysis of total RNA samples harvested at 2, 6, 12 and 20 h after infection, using conditions under which a single chlamydial transcript per infected cell is detected, three major temporal classes of gene expression were resolved. Initiation of transcription appears to occur in three temporal classes which we have operationally defined as: early, which are detected by 2 h after infection during the germination of EBs to RBs; mid-cycle, which appear between 6 and 12 h after infection and represent transcripts expressed during the growth and multiplication of RBs; or late, which appear between 12 and 20 h after infection and represent those genes transcribed during the terminal differentiation of RBs to EBs. Collectively, the data suggest that chlamydial early gene functions are weighted toward initiation of macromolecular synthesis and the establishment of their intracellular niche by modification of the inclusion membrane. Surprisingly, representative enzymes of intermediary metabolism and structural proteins do not appear to be transcribed until 10,12 h after infection; coinciding with the onset of observed binary fission of RBs. Late gene functions appear to be predominately those associated with the terminal differentiation of RBs back to EBs. [source] (631) Chronic Pain Treatment Meta-Analyses: A Mathematical and Qualitative ReviewPAIN MEDICINE, Issue 2 2000Article first published online: 25 DEC 200 Authors: Fishbain DA, University of Miami Comprehensive Pain Center; Rosomoff H, University of Miami Comprehensive Pain Center; Cutler RB, University of Miami Comprehensive Pain Center; Steele-Rosomoff R, University of Miami Comprehensive Pain Center Aim of Investigation: To critically review chronic pain treatment meta-analyses according to defined criteria. Methods: An extensive literature search yielded 22 meta-analyses dealing with pain. The following inclusion criteria were applied to these studies: (1) nonsurgical pain treatment outcome only, including nerve blocks; (2) chronic pain treatment outcome only; (3) nonmalignant pain only and; (4) study data presenting an effect size which enabled the calculation of a confidence interval (CI). These inclusion criteria selected 16 studies from the original group. These remaining meta-analyses were then divided into 3 categories: (1) General pain facility treatment (n = 4); (2) Headache treatment (n = 5) and; (3) Specific treatment types, eg, manipulation, psychoeducational, antidepressant, etc. (n = 7). Within each meta-analysis the data was subdivided according to type of pain, treatment type and outcome variable. The CI was then calculated for each of these subdivisions within each meta-analysis. The quality of the 16 meta-analyses was also investigated according to 20 meta-analysis criteria previously presented in the literature. Results: (1) Overall, the pain facility treatment meta-analyses were remarkably consistent in demonstrating that pain facility treatment is effective for most treatment outcome variables. (2) Within pain facility treatments, biofeedback, cognitive therapy, operant conditioning, and package treatment were demonstrated to be efficacious. (3) Within the headache treatment meta-analyses, both relaxation/biofeedback and various medications were demonstrated to be efficacious. (4) Within the specific isolated treatments group, psychoeducation, antidepressants, capsaicin and spinal manipulation were found to have efficacy, for a number of treatment outcome variables. (5) The quality of the meta-analyses was variable but acceptable, according to the meta-analysis criteria utilized. Conclusions: Overall the results of the reviewed meta-analyses indicate that most treatments are effective for most pain patients but that some treatments appear to be more effective than others. [source] Effects of a natural parasitical infection (Lernanthropus kroyeri) on the immune system of European sea bass, Dicentrarchus labrax LPARASITE IMMUNOLOGY, Issue 12 2009M. A. HENRY Summary The immune response of European sea bass, Dicentrarchus labrax, to a natural infection by the copepod parasite Lernanthropus kroyeri was evaluated for the first time in vivo. The results clearly demonstrated the triggering of the fish immune system by the parasite. Lysozyme activity and alternative complement pathway were involved in the early action against the parasitical infection, whilst classical complement and respiratory burst (RB) activity took over in the later stages of infection. It was hypothesized that the levels of alternative and classical complement and RB stimulation indexes may determine the resistance capacity of the fish to the parasite. It is not clear how parasites can survive despite the strong immunological arsenal deployed by the fish. The continual increase of prevalence and severity of parasite infection suggested that the parasite's mechanism of evasion of the immune system was extremely successful. The contrasting decrease in the negative effects of parasites on the fish health (such as gills anaemia) suggested that an equilibrium between the parasites and their hosts was reached in chronic infection. These dynamic interactions between parasites and fish hosts were probably the main determinant of host specificity. [source] Addition of clonidine and fentanyl: comparison between three different regional anesthetic techniques in circumcisionPEDIATRIC ANESTHESIA, Issue 11 2005ZOUHER A NAJA MD Summary Background :,Several techniques have been used for alleviating postcircumcision pain with regional anesthetics being more effective than systemic opioids. Our aim was to compare the effectiveness of dorsal penile block, ring block (RB) and dorsal penile block associated with RB in reducing postcircumcision pain in children. Methods :,We conducted a prospective randomized double-blind clinical trial on 100 boys aged between 1 month and 5 years undergoing elective circumcision. Each 20 ml of local anesthetic mixture contained 9 ml lidocaine 1% without epinephrine, 9 ml bupivacaine 0.5%, 1 ml fentanyl (50 ,g·ml,1) and 1 ml clonidine (75 ,g·ml,1). They were allocated to one of three groups: 33 boys were given a RB with 1,1.5 ml (group 1), 32 had a dorsal penile block with 1.5,4 ml (group 2) and 35 had a combined ring and dorsal penile block with 2.5,5 ml of anesthetic mixture based on the child's age. Results :,Ninety-one children (91%) completed the clinical trial (three failed blocks and six follow-up losses). The groups were similar with regard to age, weight, height, duration of surgery and hemodynamic status. The average pain scores were significantly higher with a RB compared with the other two groups (P < 0.05) for the first postoperative day. RB children and dorsal penile block children consumed significantly more analgesics for the first six postoperative hours (P < 0.05). The surgeon's satisfaction was significantly higher with the ring + dorsal penile block group (100%) compared with the other two groups (P = 0.032). Conclusion :,Dorsal penile block plus RB technique is superior to dorsal penile block alone and RB alone in reducing postcircumcision pain in children. [source] Inhibition of Aurora Kinase A enhances chemosensitivity of medulloblastoma cell lines,PEDIATRIC BLOOD & CANCER, Issue 1 2010Ayman El-Sheikh MD Abstract Background Medulloblastoma comprises approximately 20% of all primary pediatric brain tumors. Despite recent advances, the survival rate for high-risk patients and the morbidity associated with these treatments remains suboptimal. To improve outcomes and decrease morbidity, more targeted therapy is required. One possible target is the Aurora Kinase family. The objective of this study was to evaluate the impact of Aurora Kinase A inhibition in medulloblastoma cell lines. Procedure Cell proliferation was measured using an MTS assay after adding an Aurora Kinase inhibitor (C1368) at different concentrations. Cell cycle analysis was carried out by Flow Cytometry using propidium iodide (PI). RNAi experiments were performed using siRNA oligonucleotides. Luciferase experiments were carried out using the Cignal Finder 10 Pathway Reporter Arrays. Results Inhibition of Aurora Kinase A induces cell death in medulloblastoma cells and lowers the IC50 of other chemotherapeutic agents (etoposide and cisplatin) used in medulloblastoma treatment. Cell arrest at G2/M phase was significantly increased in medulloblastoma cell lines treated with C1368 Sigma at IC30 or transfected siRNA. Inhibition of Aurora Kinase A resulted in decreased activity of pro-proliferative signaling pathways including Wnt, Myc, and RB as measured by luciferase reporter assays. Conclusions These data indicate that inhibition of Aurora Kinase A inhibits cell growth in medulloblastoma through inhibition of pro-proliferative signaling pathways Wnt, Myc, and RB. Additionally, combining Aurora Kinase A inhibition with other chemotherapeutic agents significantly lowers their IC50, which make it a promising small molecule target for medulloblastoma therapy. Pediatr Blood Cancer 2010;55:35,41. © 2010 Wiley-Liss, Inc. [source] Spatial Distribution of Protein Damage by Singlet Oxygen in KeratinocytesPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2008Yu-Ying He Singlet oxygen may be generated in cells by either endogenous or exogenous photosensitizers as a result of exposure to UV or visible irradiation. We have used immuno-spin trapping (Free Radic. Biol. Med. 36: 1214, 2004) to identify the subcellular targets of singlet oxygen generated by rose bengal (RB). Confocal fluorescence microscopy of HaCaT keratinocytes incubated with RB clearly showed that the dye entered the cells and was located mainly in the perinuclear region, probably associated with the Golgi apparatus and endoplasmic reticulum. Previous studies by Wright et al. (Free Radic. Biol. Med.34: 637, 2003) have shown that long-lived protein hydroperoxides (POOH) are present in cells exposed to singlet oxygen-generating dyes. The addition of reducing metal ions such as Cu+ to POOH results in the generation of protein-derived radicals, POO, and PO,, which react with the spin trap 5,5-dimethyl-1-pyrroline N -oxide (DMPO) to give relatively stable spin adducts. In order to determine the subcellular localization of the protein-DMPO adducts, we exposed keratinocytes to RB/light exposure and then incubated the cells with Cu+ and DMPO. After staining with antibody against DMPO followed by a secondary Alexa Fluor 488 goat anti-rabbit IgG, the intracellular distribution of protein-DMPO adducts was determined by confocal microscopy. The subcellular localization of the protein DMPO adducts was coincident with that of RB. This approach may provide information on the spatial distribution of singlet oxygen generated in cells. [source] | ||||||||||||||||||||||||||||||||||||||||