Academic literature on the topic 'MCM paradox'

As a crucial component of DNA replication licensing system, minichromosome maintenance (MCM) 2–7 complex acts as the eukaryotic DNA replicative helicase. The six related MCM proteins form a heterohexamer and bind with ORC, CDC6, and Cdt1 to form the prereplication complex. Although the MCMs are well known as replicative helicases, their overabundance and distribution patterns on chromatin present a paradox called the “MCM paradox.” Several approaches had been taken to solve the MCM paradox and describe the purpose of excess MCMs distributed beyond the replication origins. Alternative functions of these MCMs rather than a helicase had also been proposed. This review focuses on several models and concepts generated to solve the MCM paradox coinciding with their helicase function and provides insight into the concept that excess MCMs are meant for licensing dormant origins as a backup during replication stress. Finally, we extend our view towards the effect of alteration of MCM level. Though an excess MCM constituent is needed for normal cells to withstand stress, there must be a delineation of the threshold level in normal and malignant cells. This review also outlooks the future prospects to better understand the MCM biology.

e23019 Background: Ductal carcinoma in situ (DCIS) is a well-known precursor of invasive ductal carcinoma (IDC). Part of patients show disease recurrence as DCIS or IDC after local treatment, but there are no established markers for prediction of recurrence. Methods: Authors analyzed 30 patients diagnosed as pure DCIS, recurrent DCIS, and IDC progressed in DCIS background. miRNA was extracted from archival tissue, and hierarchical clustering of miRNA microarray was performed. We selected highly expressed miR-17-5p and miR-106b-5p as marker for recurrence of DCIS. Two miRNAs were transfected to MCF-12 and MCF-7 cell line. Cell proliferation assay and Western blot analysis was performed for analyzing the interaction between cell proliferation and TGFβ downstream pathway. Results: miR-106b-5p single and combined miR-106b-5p and miR-17-5p transfected MCF-12 cell line showed increased proliferation index compared to un-transfected cell line. In MCF-7, miR-106b and miR-17-5p transfected cell line showed inferior proliferation index compared to un-transfected cell line. Western blot analysis showed minimal increased expression of SMAD4, phosphorylated SMAD2 (pSMAD2) in miR-106b-5p and miR-17-5p transfected MCF-12 cell line. However, decreased expression of TGFBR2 and no interval change of SMAD4 and pSMAD2 was detected in miR-106b-5p and miR-17-5p transfected MCF-7 cell line. Conclusions: miR-106-5p, miR-17-5p showed increased expression in recurrent DCIS or IDC based on miRNA hierarchical microarray. miRNA transfected MCF-12 cell line showed increased proliferation index and activated TGFβ downstream pathway. miRNA transfection might have made normal cell line to pre-cancerous cell line and TGFβ pathway might have influenced to promote tumor proliferation, based on TGFβ paradox hypothesis.

The GINS complex (a heterotetramer of Sld5, Psf1, Psf2 and Psf3) is a highly conserved DNA replication factor required for the initiation and elongation of DNA replication. GINS is believed to associate with Cdc45 and MCM proteins on replicating DNA. The interaction between GINS and MCM is also conserved in archaea. In my thesis, I explore the subcellular localisation of the GINS complex in relation to the MCM proteins and sites of DNA replication by high-resolution confocal microscopy. For these studies, I generated and carefully validated purified rabbit polyclonal and mouse monoclonal antibodies; these show a specific staining pattern by immunohistochemistry, immunoblotting and immunofluorescence. At high-resolution, all GINS antibodies produced a focal nuclear pattern, similar to that seen for the MCMs. However, confusingly, colocalisation between GINS and MCMs and between the GINS subunits themselves is poor. Investigations are continuing to understand this conundrum. Given the value of MCM proteins as specific and sensitive markers for cancer screening, I investigated whether GINS subunits also have potential diagnostic value. Sld5 and Psf3 expression is restricted to the proliferative compartment in normal tissue, but is found in the majority of cells in a wide range of dysplastic and malignant tissues, including cervix, colon and bladder. In vitro studies of tissue culture cells and cell lysates incubated in urine suggest that Sld5 protein is more stable than Mcm2 in harsh extracellular environments. In an ongoing pilot clinical study of Sld5 protein as a potential biomarker, Sld5 is readily and specifically detectable in the cellular fraction of the samples from prostate and bladder cancer patients. Work is ongoing to evaluate Sld5 protein levels in the supernatant portion of those same urine samples as an easy-to-screen diagnostic/prognostic marker for male urogenital cancers. Owing to their stability, GINS proteins hold promise as independent or complementary markers to the MCM proteins for cancer screening in harsh extracellular environments such as urine.

L’objectif de notre étude est d’améliorer la connaissance des réseaux neuronaux responsables de la régulation du sommeil paradoxal (SP). Dans ce but, nous avons combiné des techniques de polysomnographie, de neuroanatomie fonctionnelle, de pharmacologie et de traçage de voies nerveuses. Nous avons ainsi mis en évidence une population de neurones GABAergiques à la jonction entre la substance grise périaqueductale ventrolatérale et la partie dorsale du noyau profond du mésencéphale (vlPAG/dDpMe), capable de bloquer l’entrée en SP. Nous avons également démontré l’existence de nombreuses populations de neurones GABAergiques pontiques activés au cours du SP. De plus, nos travaux ont révélé la présence de nombreux neurones GABAergiques, dont les neurones à MCH, actifs en SP dans plusieurs régions hypothalamiques. Enfin, nous avons établi une cartographie des neurones à MCH et à Hcrt envoyant des projections sur les neurones histaminergiques du noyau tubéromammillaire ventral (VTM), promoteurs de l’éveil. L’ensemble de notre travail de thèse a permis d’affiner le modèle des réseaux neuronaux impliqués dans la régulation du SP, particulièrement en confirmant le rôle du GABA dans ces mécanismes de régulation
The aim of our study is to improve the knowledge of the neural networks responsible for paradoxical sleep (PS) regulation. To this end, we combined polysomnographic recordings, functional neuroanatomy, pharmacology and tract-tracing of nervous pathways. We thus highlighted a population of GABAergic neurons at the junction between the ventroleral periaqueductal gray and the dorsal part of the deep mesencephalic nucleus (vlPAG/dDpMe), able to gate PS genesis. We also showed the existence in the pons of several GABAergic neurons populations activated during PS. Moreover, our work revealed the presence of a large number of GABAergic neurons including the MCH neurons, activated in PS in several hypothalamic areas. Finally, we mapped the MCH, Hcrt neurons that send projections to the wake-promoting histaminergic neurons of the ventral tuberomammillary nucleus (VTM). Our thesis work made it possible to refine the model of neural networks involved in PS regulation, particularly by confirming the role of GABA in these mechanisms of regulation

Les mécanismes neurologiques responsables du déclenchement et de l'homéostasie du sommeil, et du sommeil paradoxal (SP) en particulier, sont l'objet d'un nombre toujours plus important d'études du fait notamment de l'attention croissante portée aux pathologies associées. Les travaux rapportés dans cette thèse s'inscrivent parfaitement dans cette dynamique puisqu'ils ont pour objectif de mieux caractériser les populations neuronales mises en jeu dans la régulation du SP ainsi que leurs interactions. Dans cette optique, nous avons combiné différentes approches techniques complémentaires à savoir : neuroanatomie fonctionnelle, polysomnographie et pharmacologie sur animal libre de se mouvoir. Nous avons ainsi pu démontrer pour la première fois la nature glutamatergique des neurones du SLD, région pontique jouant un rôle central dans la mise en place du SP. De plus, s'il est généralement admis que ces neurones du SLD sont sous le contrôle de neurones GABAergiques situés au niveau de la partie ventrolatérale de la substance grise périaqueducale (VLPAG), le contrôle de ces derniers est encore soumis à controverse. Les résultats que nous avons obtenus suggèrent fortement que l'aire latérale de l'hypothalamus (LH) serait responsable de ce contrôle et donc de celui du SP. En effet, la LH est l'afférence majeure à la VLPAG activée lors d'une hypersomnie de SP. En outre, son inactivation par application locale de muscimol entraine la disparition totale du SP et l'activation des neurones GABAergiques de la VLPAG projetant sur le SLD. En parallèle, nous avons étudié le rôle du noyau réticulé paragigantocellulaire dorsal (DPGi) dans la genèse du SP. Bien que le DPGi fût déjà connu pour être responsable de l'inhibition du locus coeruleus (LC) durant les phases de SP, nous apportons ici un certain nombre d'arguments suggérant que le DPGi pourrait être responsable de l'inhibition, non seulement du LC, mais également de l'ensemble des neurones adrénergiques et noradrénergiques. Cela suggère donc que ce noyau joue également un rôle majeur dans la régulation du SP. Les données rapportées dans cette thèse permettent donc de mieux appréhender les mécanismes neuronaux contrôlant la survenue et la régulation du SP. En particulier, ils apportent de nouvelles données en faveur d'un rôle central de l'hypothalamus dans la régulation du SP puisqu'il constituerait le générateur principal de cet état.

Chez les mammifères, l’alternance des états de vigilance nécessite la mise en jeu de mécanismes spéci ques qui facilitent les transitions entre l’éveil, le sommeil lent (SL) et le sommeil paradoxal (SP). L’objectif de cette thèse s’inscrit dans l’optique de disséquer chez la souris les processus neuronaux contrôlant l’alternance physiologique entre ces trois états de vigilance. Au cours de cette thèse, nous avons tout d’abord démontré par des approches complémentaires ex vivo et in vivo que le glucose peut favoriser l’endormissement par son action excitatrice directe sur les neurones promoteurs du SL localisés dans l’aire préoptique ventrolatérale (VLPO). Nous avons ensuite, par deux approches méthodologiques di érentes et complémentaires, contribué à préciser le rôle physiologique des neurones exprimant l’hormone de mélano-concentration (MCH) dans la régulation du cycle veille-sommeil, démontrant ainsi qu’en plus de faciliter le déclenchement et le maintien du SP lorsqu’ils sont activés, ils contrôlent certains aspects du SL en favorisant, au cours SL, un SL plus profond ainsi que la terminaison des épisodes de SL. Forts de ces nouveaux résultats supportant une contribution des neurones MCH à la régulation du SL, nous avons déterminé une voie potentielle pouvant sous-tendre cette fonction physiologique à travers leurs projections efférentes sur le VLPO. Nos résultats préliminaires indiquent que la stimulation optogénétique des axones des neurones MCH dans le VLPO favorise le déclenchement d’un état de transition entre SL et SP sans pour autant conduire au SP
In mammals, alternating between vigilance states requires some speci c processes that facilitate transitions between wake, Slow-Wave Sleep (SWS), and Paradoxical Sleep (PS). The objective of this thesis was to decipher, in mice, the neuronal mechanisms that control the alternation between these three vigilance states. During thus thesis, we first demonstrated using complementary ex vivo and in vivo approaches that glucose can facilitate sleep induction by directly exciting sleep- promoting neurons located within the ventrolateral preoptic nucleus (VLPO). Then, by developing two different and complementary approaches, we contributed to clarify the physiological role of melanin-concentrating hormone (MCH)-expressing neurons in sleep-wake regulation. Indeed, in addition to their PS-promoting effect when activated, we found that MCH neurons also contribute to the regulation of some aspects of SWS regulation by favouring the appearance of a deeper SWS and facilitating SWS episodes termination. These new results supporting a role of MCH neurons to SWS regulation led us to investigate a putative pathway underlying such an effect through efferent projections from MCH neurons to the VLPO. Preliminary results suggest that the optogenetic stimulation of axons from MCH neurons within the VLPO could facilitate the appearance of a transition state between SWS and PS without triggering PS onset

Il est maintenant établi que le sommeil paradoxal (SP) facilite certaines formes de mémoires dépendantes de l'hippocampe bien que les mécanismes impliqués restent mal compris. Des résultats de l'équipe et d'autres laboratoires suggèrent toutefois que cet effet facilitateur serait en partie sous-tendu par une modulation de la plasticité synaptique de longue durée dans l'hippocampe. Nos travaux se proposent donc d'étudier ces mécanismes chez la souris, à l'échelle synaptique et systémique. Pour cela nous nous avons privilégié trois approches : 1) La caractérisation comportementale et électrophysiologique du rôle des neurones à Hormone de Mélano-Concentration (MCH), une hormone hypothalamique libérée principalement pendant le SP, qui pourrait être un acteur associé au SP, impliqué dans la formation ou la consolidation de nouveaux apprentissage ; 2) L'étude de la neuromodulation de la transmission synaptique hippocampique induite par la MCH ; 3) Une étude du rôle du SP dans le remodelage des réseaux corticaux de la mémoire prenant place pendant les processus de consolidation à court et long terme d'un conditionnement contextuel à la peur. L'ensemble de nos résultats indique que le SP, grâce notamment à des effecteurs moléculaires comme la MCH, peut moduler la plasticité synaptique hippocampique et ainsi intervenir aussi bien dans la formation que la consolidation à long terme des souvenirs
It is now established that paradoxical sleep (PS) facilitates some hippocampaldependent memory forms although mechanisms implied are still not well understood. However, results from our lab and others suggest that part of this facilitating effect is underlined by hippocampal long term synaptic plasticity modulation. Our work investigates these mechanisms in mice, at a synaptic and systemic scale. We opted for three different approaches: 1) A behavioural and electrophysiological characterization of the role of Melanin-Concentrating Hormone (MCH) neurons. Indeed, as this hypothalamic hormone is mainly liberated during PS, it could be a PS associated effector implied in formation or consolidation of new memories ; 2) A study of neuromodulating effects on hippocampal synaptic transmission induced by MCH ; 3) A study of PS role in memory cortical networks remodeling happening during short and long-term consolidation of a contextual fear conditioning task. Altogether, our results point out that PS modulates hippocampal synaptic plasticity, notably through molecular effectors such as MCH, and thus takes part in both encoding and long-term consolidation of memories process

Relativity is a set of remarkable insights into the way space and time work. The basic notion of relativity, first articulated by Galileo, explains why we do not feel Earth moving as it orbits the Sun and was successful for hundreds of years. We present thinking tools that elucidate Galilean relativity and prepare us for the more modern understanding. We then show how Galilean relativity breaks down at speeds near the speed of light, and follow Einstein’s steps in working out the unexpected relationships between space and time that we now call special relativity. These relationships give rise to time dilation, length contraction, and the twin “paradox” which we explain in detail. Throughout, we emphasize how these effects are tightly interwoven logically and graphically. Our graphical understanding leads to viewing space and time as a unified entity called spacetime whose geometry differs from that of space alone, giving rise to these remarkable effects. The same geometry gives rise to the energy?momentum relation that yields the famous equation E = mc2, which we explore in detail. We then show that this geometric model can explain gravity better than traditional models of the “force” of gravity. This gives rise to general relativity, which unites relativity and gravity in a coherent whole that spawns new insights into the dynamic nature of spacetime. We examine experimental tests and startling predictions of general relativity, from everyday applications (GPS) to exotic phenomena such as gravitomagnetism, gravitational waves, Big Bang cosmology, and especially black holes.

Falar da atuação do Profissional de Educação Física no SUS para mim é um prazer e um dever. PRAZER porque é bom falar daquilo que gostamos e o DEVER onde me cabe apontar, fiscalizar e promover as ações e dar visibilidade a nossa profissão da melhor maneira possível. Ver o quanto podemos fazer na saúde pública e não ter isso registrado, formalizado, foi pra mim a mola propulsora para organizar esse e-book. Confesso que desde o princípio sabia que ia dar certo. Quando comecei a entrar em contato com os colegas de outros estados, pude sentir em suas vozes a certeza de que queiram a mesma coisa que eu, ou seja, dar vazão aquilo que realizavam no SUS, mas que não tinha a sua valorização, o seu reconhecimento. Não acordamos em busca de reconhecimento, mas sim, merecimento. Merecemos ser valorizados, merecemos ser lembrados, merecemos ter o nosso espaço definido dentro de tantos outros já consolidados. Foi com imensa alegria que recebi os aceites dos colegas e assim organizando essa bela coletânea de relatos de experiência, em formato digital, intitulado de COGITO ERGO “SUS”: RELATOS DE EXPERIÊNCIAS DE PROFISSIONAIS DE EDUCAÇÃO FÍSICA NO SUS. “ Esse título nos remete a expressão latina “cogito ergo sum” que significa “Penso, logo sou”. A inclusão da palavra SUS nesta expressão para mim tem o valor notório que pensamos em SUS em todas as nossas ações sendo estas realizadas nos cenários de práticas, nos territórios sanitários ou qualquer outro espaço de saúde pública, na certeza de que promoveremos saúde e qualidade de vida a todos os usuários do sistema público de saúde. Este livro digital, escrito por mãos de especialistas, oferece um forte diferencial de relatos de experiencia na atuação de Profissionais de Educação Física no SUS. Os colaboradores deste livro digital apresentam um olhar direcionado para o lado humano, enxergando inúmeras perspectivas e caminhos a serem seguidos na direção da formação integral e investindo no potencial que cada um traz consigo, na intenção de se desenvolver, evoluir e transpor os seus limites, a fim de conquistar seus lugares na sociedade e vivenciar experiências longe de padrões adotados cultural e historicamente, que muitas vezes desconsideram o real significado de humanidade. Estes profissionais, e eu me incluo neste grupo, acreditam e lutam por uma sociedade inclusiva com práticas que envolvem a equidade e o respeito por toda a diversidade. Sendo assim, o ebook está regionalizado, proporcionado dessa forma uma viagem de norte a sul do país, do Caburai/RR ao Chuí/RS, com textos de fácil leitura e repleto de intencionalidades durante as diversas práticas corporais e intervenções proporcionadas aos usuários do sistema, comumente chamados os pacientes do SUS. Na região norte pudemos perceber o quanto o regionalismo está presente, principalmente nas nomenclaturas dos territórios de saúde. Na região nordeste, considerada a região com maior número de estados, num total de 9 estados, colabora com relatos de experiencias inigualáveis, começando desde os Programas de Residências, até a atuação cega, mas altamente segura das equipes de NASF-AP. Digo cega pois temos normas a seguirem, porém não temos modelos a quem nos espelhar, o que faz de cada equipe de NASF-AP o seu próprio modelo a seguir, atestando a máxima de que “não importa se está certo ou errado, o que vale é o que está combinado”. Descendo o mapa e parando no coração do Brasilllllll, chegamos à região centrooeste, região que me deixa extremamente a vontade em parafrasear Manoel... (colocar uma fala dele), considerado um ícone da cultura pantaneira, fauna e flora abundante e que reflete nas práticas corporais dessa região, diversas sensações e experiencias inigualáveis. Ter contato com ações realizadas na capital federal não é para qualquer um. Região Sudeste... uma megalópole reunida em 4 estados, São Paulo, Rio de Janeiro, Minas Gerais e Espirito Santo. Linha de passagem para quem sobe ou para quem desce na geografia brasileira. Uma mistura de povos e culturas expressas em relatos técnicos-científicos. E por fim, região sul, a minha região. Nascido no Paraná, mas transitando entre os outros 2 estados, Santa Catarina e Rio Grande do Sul, poderemos experimentar relatos típicos da região, mas também intervenções profissionais pontuais na promoção da saúde e qualidade de vida, em meio a pandemia. Ah, já ia me esquecendo desse tal COVID-19, uma mudança radical na dinâmica de trabalho, mas que não nos desanimou de forma alguma, promovendo saúde e qualidade de vida via redes sociais. O SUS não pode parar, não é! De uma forma ou de outra, soubemos manter a saúde física e mental em meio a esta pandemia, na certeza de que os nossos usuários precisariam bem mais de nós neste momento tão inseguro. Utilizo uma frase que cabe bem no momento que estamos vivendo: “Do pouco que fazemos, pode ser muito para eles (usuários)”. Uma leitura rica e agradável, na expectativa de que esse time de sucesso possa oferecer com amor e competência dados que qualificam e validam a atuação do Profissional de Educação Física na saúde pública brasileira. Sou do SUS... Vivo o SUS...

It was difficult for Willson to choose a follow-up to The Music Man because it was such a big hit. This chapter charts his struggles with his second musical The Unsinkable Molly Brown, including the problems with the show’s director, Dore Schary, which are revealed through newly uncovered production documents. The musical is based on the real life exploits of Molly Brown, who survived the sinking of the Titanic, and was a modest success upon its debut on Broadway. The chapter also briefly explores the 1964 MGM film adaptation starring Debbie Reynolds.

El análisis de las señales cerebrales para la asistencia en pacientes con movilidad reducida es un área de investigación continua en la que las nuevas tecnologías ofrecen un amplio espectro de posibilidades para la ayuda activa como los exoesqueletos y las interfaces cerebro-maquinas (BMI). En este trabajo nos centramos en realizar una interfaz BMI para el control de velocidad del miembro inferior. El objetivo de este estudio es analizar las señales electroencefalográficas (EEG) para obtener un indicador que relacione la información cerebral con marcadores de velocidad en la marcha. Para el procesamiento de las señales EEG analizamos los ritmos sensoriomotores correspondientes a las bandas Alfa y Beta en la zona motora. La interfaz BMI debe discernir entre dos estados marcha e intención de cambiar de velocidad. La creación de dicho modelo requiere caracterizar el momento del cambio, para la fase de entrenamiento. Hemos utilizado el equipo de captura de movimiento Tech MCS V3 basado en sensores inerciales. Analizamos las componentes frecuenciales de la aceleración en el dominio temporal mediante la transformada continua Wavelet (CWT). En este trabajo realizamos un estudio menor para analizar la marcha y otro principal para la validación de la interfaz BMI planteada. Tres usuarios sanos participaron en el estudio. El protocolo tiene tres fases, el usuario espera parado unos segundos tras los cuales decide comenzar la marcha a un ritmo visiblemente lento y llegado un punto voluntariamente cambia de velocidad manteniéndola unos segundos. El experimento consta de 40 repeticiones. Debido a la gran generación de artefactos durante la marcha los componentes de la señal EEG fueron descompuestos mediante ICA y rechazados según su componente espectral y un criterio apropiado. Los resultados fueron procesados con varias configuraciones de electrodos de la zona motora, en diferentes bandas de frecuencia y con y sin eliminación de artefactos. El porcentaje máximo de acierto para los tres usuarios a la hora de distinguir entre las dos clases es del 58%, no siendo resultados lo suficientemente remarcables para poder validar de forma confiable la interfaz BMI planteada.