Connexin Trafficking And The Control Of Gap Junction Assembly In The Mouse Preimplantation Embryo

Gap junction assembly in the preimplantation mouse embryo is a temporally regulated event, beginning a few hours after the third cleavage during the morphogenetic event known as compaction. The purpose of the present study was to determine which connexins contribute to gap junctions in the preimplantation mouse embryo and how their assembly into gap junctions at compaction is regulated. Using antibodies raised against different synthetic C-terminal peptides of connexin43 (Cx43), this protein was shown to assemble into gap junction-like plaques beginning with compaction. Prior to this time no Cx43 can be detected in the plasma membrane. Cell fractionation and reverse transcription-polymerase chain reaction (RT-PCR) were employed to show that Cx43 mRNA is in polyribosomes at the 4-cell stage, suggesting that synthesis of Cx43 begins at least one cell cycle in advance of when gap junctions first form. The fate of nascent Cx43 was followed throughout preimplantation development by means of immunofluorescence in conjunction with confocal laser scanning microscopy. In morulae and blastocysts Cx43 becomes differentially distributed in the apposed plasma membranes: a zonular distribution predominates between outside blastomeres and trophectoderm cells whereas plaque-like localizations predominate between inside blastomeres and cells of the inner cell mass. The cytoplasmic immunoreactivity in morulae was deemed to be nascent connexin en route to the plasma membrane since it could be abolished by treatment with cycloheximide, and redistributed by treatment with monensin or brefeldin-A, known inhibitors of protein trafficking. These latter two drugs were shown to cause specific alterations in the structure and distribution of a variety of organelles in morulae, especially those involved in protein trafficking and degradation.;No conclusive evidence for the contribution of connexin32 (Cx32) to gap junctions in morulae could be found. However, using immunogold electron microscopy, the contribution of Cx43 was confirmed. Cx43 was also found to contribute to gap junctions in cumulus-oocyte complexes (COCs), both between cumulus granulosa cells and these cells and the oocyte. Although 100% of gap junctions between cumulus cells were labeled with Cx43 specific antisera, over 30% of gap junctions in morulae were not. Thus other members of the connexin gene family may yet be found to contribute to gap junctions at this stage. Treatment of uncompacted 8-cell embryos with either monensin or brefeldin-A inhibited the appearance of gap junction-like structures containing Cx43 and the onset of gap junctional coupling in a reversible manner. These data demonstrate that the onset of gap junction assembly during compaction is regulated post-translationally and involves mobilization of connexin43 and possibly other members of the connexin gene family through trafficking organelles to plasma membranes

Sufficiency of hypoxia-inducible 2-oxoglutarate dioxygenases to block chemical oxidative stress-induced differentiation of human embryonic stem cells

Hypoxia benefits undifferentiated pluripotent stem cell renewal, and 2-oxoglutarate (2OG) dioxygenases have been implicated in pluripotent stem cell induction and renewal. We show in human embryonic stem cells (hESC) that an ambient oxygen-induced oxidative stress response elicited by culture in a hypoxic atmosphere (0.5% O2) correlates with the expression of 2OG dioxygenases, which oxidise DNA (TET1, 2, 3) and histone H3 (KDM4C), the former reflected by elevation in genomic 5-hydroxymethylcytosine (5hmC). siRNA-mediated targeting of KDM4C and TET1–3 induces hESC differentiation. Under ambient atmospheric oxygen (21% O2), exposure to a low inhibitory concentration of sodium arsenite (NaAsO2, IC10), as a model of chemically-induced oxidative stress, suppresses antioxidant gene expression, reduces mitochondrial membrane potential and induces hESC differentiation. Co-administration of the antioxidant N-acetyl-L-cysteine promoted anti-oxidant, pluripotency and 2OG dioxygenase gene expression, elevated genomic hydroxymethylation and blocked induction of differentiation. Transient ectopic expression of KDM4C or TET1 in ambient atmospheric oxygen achieved the same. Our study substantiates a role for 2OG-dependent dioxygenases in hypoxia's promotion of undifferentiated hESC self-renewal

Dielectrophoresis: A Review of Applications for Stem Cell Research

Dielectrophoresis can discriminate distinct cellular identities in heterogeneous populations, and monitor cell state changes associated with activation and clonal expansion, apoptosis, and necrosis, without the need for biochemical labels. Demonstrated capabilities include the enrichment of haematopoetic stem cells from bone marrow and peripheral blood, and adult stem cells from adipose tissue. Recent research suggests that this technique can predict the ultimate fate of neural stem cells after differentiation before the appearance of specific cell-surface proteins. This review summarises the properties of cells that contribute to their dielectrophoretic behaviour, and their relevance to stem cell research and translational applications

A tool for implementing privacy in Nano

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.We present a work in progress strategy for implementing privacy in Nano at the consensus level, that can be of independent interest. Nano is a cryptocurrency that uses an Open Representative Voting (ORV) as a consensus mechanism, a variant of Delegated Proof of Stake. Each transaction on the network is voted on by representatives, and each vote has a weight equal to the percentage of their total delegated balance. Every account can delegate their stake to any other account (including itself) and change it anytime it wants. The goal of this paper is to achieve a way for the consensus algorithm to function without knowing the individual balances of each account. The tool is composed of three different schemes. The first is a weighted threshold secret sharing scheme based on the Chinese Remainder Theorem for polynomial rings [1] and it's used to generate, in a distributed way, a secret that will be a private key of an additive ElGamal cryptosystem over elliptic curves (EC-EG) [2], which is additive homomorphic. The second scheme is the polynomials commitment scheme presented in [3] and is used to make the previous scheme verifiable, i.e., without the need of a trusted dealer. Finally, the third scheme is used to decrypt a ciphertext of the EC-EG cryptosystem without reconstructing the private key and, because of that, can be used multiple times.IEEEinfo:eu-repo/semantics/submittedVersio

Validation of the Saint George's Respiratory Questionnaire in patients with chronic obstructive pulmonary disease in Brazil

Introduction: The term quality of life has gained increasing importance in the scientific context. This study describes the adaptation of a disease-specific questionnaire developed by Paul Jones et al. in 1991, the St. George's Respiratory Questionnaire (SGRQ), to the Brazilian language and culture. This questionnaire evaluates the quality of life in patients with chronic obstructive pulmonary disease (COPD) and contains three domains (symptoms, activity, and impacts) divided in 76 items. The questionnaire is self-administrated, but it may be read to illiterate persons. Goal: To verify if the St. George's Respiratory Questionnaire is a valid tool to measure quality of life in patients with chronic obstructive pulmonary disease in Brazil. Methods: In order to validate the questionnaire in Brazil, it was initially translated into Portuguese and afterwards a back-translation into English, that was compared to the original version. A final Portuguese version was then written. This final version was, then, answered by 30 clinically stable COPD patients, according to the spirometry and oximetry values. Patients answered the questionnaire twice, within a 15 day interval. The length of time the patients took to answer the questionnaire and their doubts were noted. Wilcoxon test was used for the calculation of r probability between every single question between the two days; interclass correlation ratio was calculated to test the trustworthiness and reliability of the questionnaire. Results: Among the 30 participant patients, 10 were female and 20 were male. Mean age was 65.9 years. Most of the patients were found to be in stage 2 (56.7 %) of COPD, according to the American Thoracic Society classification. The interclass correlation ratio for the total score of the questionnaire was a = 0.79 and Wilcoxon p = 0.2110 (not statistically significant). The mean answering time for the two days of interview was, respectively, 11 minutes and 50 seconds and 10 minutes and 31 seconds. As concerns the doubts about the questions, the patients reported difficulties in answering Sections 4 and 5, each one of these questions written in a negative form. Conclusion: It can be concluded that the Brazilian version of the St. George's Respiratory Questionnaire is a valid and reliable tool to measure quality of life in patients with COPD in Brazil.Introdução: O termo qualidade de vida tem adquirido cada vez mais importância no contexto científico. O presente estudo descreve a adaptação para as língua e cultura brasileiras de um questionário doença-específico desenvolvido por Paul Jones et al. em 1991(1): o Questionário do Hospital Saint George na Doença Respiratória (SGRQ), para a avaliação de qualidade de vida em pacientes portadores de doença pulmonar obstrutiva crônica (DPOC). Esse questionário contém três componentes (sintomas, atividade e impactos) divididos em 76 itens. É auto-administrado e pode ser lido para pacientes analfabetos. Objetivo: Verificar se o SGRQ é um instrumento válido para medir qualidade de vida em pacientes portadores de DPOC no Brasil. Métodos: Para a validação deste questionário no Brasil, realizou-se, inicialmente, uma versão da língua inglesa para o português; em seguida, foi realizada a tradução retrógrada (back translation), do português para o inglês, e uma versão final foi aplicada em 30 pacientes com diagnóstico de DPOC, estáveis clinicamente e baseado em critérios de espirometria e oximetria. Os pacientes responderam ao questionário por duas vezes, num intervalo de 15 dias. O tempo de resposta foi cronometrado e as dúvidas apontadas pelos pacientes, anotadas. Foi utilizado o teste estatístico de Wilcoxon para cálculo de probabilidade de r e calculado o coeficiente de correlação intraclasse para testar a fidedignidade e a confiabilidade do questionário. Resultados: Dos 30 pacientes que participaram do estudo, 10 eram do sexo feminino e 20 do masculino. A média de idade foi de 65,9 anos. A maioria dos pacientes encontrava-se no estádio 2 (56,7%) da DPOC, segundo a classificação da American Thoracic Society. O coeficiente de correlação intraclasse para a pontuação total do questionário foi a = 0,79 e o resultado do teste de Wilcoxon p = 0,2110 (não significante estatisticamente). O tempo médio de resposta dos dois dias de entrevista foi, respectivamente, 11 minutos e 50 segundos e 10 minutos e 31 segundos. Em relação às dúvidas, as questões mais freqüentemente referidas foram as das seções 4 e 5, que contêm uma frase cada na forma negativa. Conclusão: Pode-se concluir que a versão brasileira do Questionário do Hospital Saint George na Doença Respiratória (SGRQ) é um instrumento válido e fidedigno para medir qualidade de vida em pacientes portadores de DPOC no Brasil.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaCentro Universitário de UberlândiaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Centro de Reabilitação PulmonarUniversity of LondonUNIFESP, EPM, Centro de Reabilitação PulmonarSciEL

A luz da representação, os ambientes luminosos na prática artística

O presente trabalho constitui uma pesquisa com o propósito de aprofundar o conhecimento da representação da luz em obras artísticas, nomeadamente na pintura, nas instalações e no cinema. A luz sempre suscitou questões desde a sua natureza e origem até à reflexão sobre os seus efeitos. Nas expressões artísticas houve e há muitas formas de trazer à presença esse elemento que nem sempre é fácil de reproduzir. O foco de interesse é o efeito que a luz tem nestes meios de expressão, sobre a forma como as obras são produzidas, percecionadas e na relação que o indivíduo estabelece com as mesmas. É neste âmbito que o estudo se desenvolve, em duas vertentes, sendo uma a da luz na representação, com o examinar dos procedimentos na produção de efeitos de luz, e a outra, a luz da representação através da observação dos efeitos resultantes em obras artísticas. O trabalho é composto por três partes. A primeira estuda a luz e a sombra e sua interligação. A segunda parte dedica-se ao aprofundar da relação com a luz em cinco áreas: a perceção, o ambiente circundante, a arquitetura, a pintura e o cinema. O terceiro capítulo aprofunda a pesquisa a partir de três casos de estudo: Mark Rothko, na pintura, James Turrell, na instalação e Christian Berger, no cinema. Estes artistas têm aspetos comuns, destacando-se o facto de todos eles, por um lado, darem uma importância significativa à função da luz e, por outro, procurarem uma nova abordagem na forma de representação no âmbito dos seus respetivos meios. Conclui-se que, para além dos ambientes luminosos produzidos, é essencial o papel do indivíduo que irá completar o efeito dos mesmos com a sua vivência da obra, o modo como se processa a perceção e como o indivíduo se relaciona com o espaço envolvente e a sua experiência de vida, social e cultural. Por outro lado, as observações da luz natural dos elementos e da atmosfera, permitem encontrar as suas características essenciais o que, por sua vez, viabiliza a sua representação.The present work discusses the research that has been undertaken with the purpose of deepening the knowledge about the representation of light in artistic work, specifically in painting, installations and in cinema. Light has always raised questions that range from its nature and origin to ponderations about is effects. In the artistic expressions there have been, and are, many ways to represent this element which is not always easy to reproduce. The interest is focused on the effect that light creates in these mediums of expression as well as on the way these works are produced, perceived, and, finally, in the way the viewer relates to them. Within this framework the study dwells on two aspects, one being light in the representation, which examines the processes used in the production of light effects, and the other, the light of the representation, where the resulting effects in artistic works are observed. The study is composed of three parts. The first deals with light and shadow and their interconnection. The second examines more closely the relationship with light in five areas: perception, environment, architecture, painting and cinema. In the third chapter light is investigated more deeply on the basis of three case studies: Mark Rothko as regards painting, James Turrell with respect to installation and Christian Berger in cinema. These three artists share common aspects, among which the fact stands out that all of them, on the one hand, attribute significant importance to the function of light and, on the other that, in their respective medium, they search for a new approach in the form of representation The research concludes that, in addition to the produced light environments, essential importance is to be attributed to the role of the viewer who will complete their effect with the way he experiences the work, the way his perception is processed, how he relates with the surrounding space, and with his social and cultural life experience. On the other hand, observing the natural light of things and the atmosphere makes it possible to find its essential characteristics which, in turn, permits its representation

Delegated RingCT: faster anonymous transactions

We present a modification to RingCT protocol with stealth addresses that makes it compatible with Delegated Proof of Stake based consensus mechanisms called Delegated RingCT. Our scheme has two building blocks: a customised version of an Integrated Signature and Encryption scheme composed of a public key encryption scheme and two signature schemes (a digital signature and a linkable ring signature); and non-interactive zero knowledge proofs. We give a description of the scheme, security proofs and a prototype implementation whose benchmarking is discussed. Although Delegated RingCT does not have the same degree of anonymity as other RingCT constructions, we argue that the benefits that the compatibility with DPoS consensus mechanisms brings constitute a reasonable trade-off for being able to develop an anonymous decentralised cryptocurrency faster and more scalable than existing ones

Détection du passage à l'acte violent en unité psychiatrique et interventions infirmières: travail de Bachelor

La violence dans les soins est un phénomène en pleine expansion dans le monde de la santé. Les unités psychiatriques sont les plus touchées dû à plusieurs facteurs. Dès lors, la psychose apparait comme étant la pathologie psychiatrique la plus associée à la violence. Cette violence a de nombreux impacts négatifs sur la qualité de la prise en soins. L'objectif de cette revue de littérature est de mettre en exergue des outils de dépistage de la violence mis à disposition des soignants. Puis, de pouvoir identifier les interventions infirmières appliquées lors d'apparition de signes précurseurs de la violence