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A fundamental question associated with chirality is how mixtures containing equal amounts of interconverting enantiomers can spontaneously convert to systems enriched in only one of them. Enantiomers typically have similar chemical properties, but can exhibit distinct reactivity under specific conditions, and these differences can be used to bias the system's composition in favor of one enantiomer. Transport properties are also expected to differ for enantiomers in chiral solvents, but the role of such differences in chiral symmetry breaking has not been clarified yet. In this work, we develop a theoretical framework to show that asymmetry in diffusion properties can trigger a spontaneous and selective symmetry breaking in mixtures of enantiomers. We derive a generic evolution equation for the enantiomeric excess in a chiral solvent. This equation shows that the relative stability of homochiral domains is dictated by the difference of diffusion coefficients of the two enantiomers. Consequently, deracemization toward a specific enantiomeric excess can be achieved when this difference is large enough. These results hold significant implications for our understanding of chiral symmetry breaking.
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ABCB5 is a member of the ABC transporter superfamily composed of 48 transporters, which have been extensively studied for their role in cancer multidrug resistance and, more recently, in tumorigenesis. ABCB5 has been identified as a marker of skin progenitor cells, melanoma, and limbal stem cells. It has also been associated with multidrug resistance in several cancers. The unique feature of ABCB5 is that it exists as both a full transporter (ABCB5FL) and a half transporter (ABCB5ß). Several studies have shown that the ABCB5ß homodimer does not confer multidrug resistance, in contrast to ABCB5FL. In this study, using three complementary techniques, (1) nanoluciferase-based bioluminescence resonance energy transfer, (2) coimmunoprecipitation, and (3) proximity ligation assay, we identified two novel heterodimers in melanoma: ABCB5ß/B6 and ABCB5ß/B9. Both heterodimers could be expressed in High-Five insect cells and ATPase assays revealed that both functional nucleotide-binding domains of homodimers and heterodimers are required for their basal ATPase activity. These results are an important step toward elucidating the functional role of ABCB5ß in melanocytes and melanoma.
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Subfamília B de Transportador de Cassetes de Ligação de ATP , Melanoma , Humanos , Adenosina Trifosfatases/metabolismo , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/isolamento & purificação , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Melanoma/genética , Melanoma/fisiopatologia , Células HEK293RESUMO
Marantaceae forests are tropical rainforests characterized by a continuous understory layer of perennial giant herbs and a near absence of tree regeneration. Although widespread in West-Central Africa, Marantaceae forests have rarely been considered in the international literature. Yet, they pose key challenges and opportunities for theoretical ecology that transcend the borders of the continent. Specifically, we ask in this review whether open Marantaceae forests and dense closed-canopy forests can be considered as one of the few documented examples of alternative stable states in tropical forests. First, we introduce the different ecological factors that have been posited to drive Marantaceae forests (climate, soil, historical and recent anthropogenic pressures, herbivores) and develop the different hypotheses that have been suggested to explain how Marantaceae forests establish in relation with other vegetation types (understory invasion, early succession after disturbance, and intermediate successional stage). Then, we review the underlying ecological mechanisms that can explain the stability of Marantaceae forests in the long term (tree recruitment inhibition, promotion of and resilience to fire, adaptive reproduction, maintenance by megaherbivores). Although some uncertainties remain and call for further empirical and theoretical research, we found converging evidence that Marantaceae forests are associated with an ecological succession that has been deflected or arrested. If verified, Marantaceae forests may provide a useful model to understand critical transitions in forest ecosystems, which is of particular relevance to achieve sustainable forest management and mitigate global climate change.
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Florestas , Floresta Úmida , Árvores/fisiologia , ÁfricaRESUMO
ABCB5ß is a member of the ABC transporter superfamily cloned from melanocytes. It has been reported as a marker of skin progenitor cells and melanoma stem cells. ABCB5ß has also been shown to exert an oncogenic activity and promote cancer metastasis. However, this protein remains poorly characterized. To elucidate its subcellular localization, we tested several anti-ABCB5 antibodies and prepared several tagged ABCB5ß cDNA constructs. We then used a combination of immunofluorescence and biochemical analyses to investigate the presence of ABCB5ß in different subcellular compartments of HeLa and MelJuSo cell lines. Treatment of the cells with the proteasome inhibitor MG132 showed that part of the population of newly synthesized ABCB5ß is degraded by the proteasome system. Interestingly, treatment with SAHA, a molecule that promotes chaperone-assisted folding, largely increased the expression of ABCB5ß. Nevertheless, the overall protein distribution in the cells remained similar to that of control conditions; the protein extensively colocalized with the endoplasmic reticulum marker calnexin. Taken together with cell surface biotinylation studies demonstrating that the protein does not reach the plasma membrane (even after SAHA treatment), the data indicate that ABCB5ß is a microsomal protein predominantly localized to the ER.
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Transportadores de Cassetes de Ligação de ATP , Retículo Endoplasmático , Humanos , Transportadores de Cassetes de Ligação de ATP/metabolismo , Retículo Endoplasmático/metabolismo , Chaperonas Moleculares/metabolismo , Células HeLa , Isoformas de Proteínas/metabolismo , Trifosfato de Adenosina/metabolismoRESUMO
The 5-fluoro triazole amino acid scaffold prepared by halogen exchange has been incorporated into peptides. From the X-ray diffraction of the 5-fluoro triazole motif, the main observation was an important localization on one side of the negative potential surface. The fluorine atom reveals a cylindrical shape in its deformation electron density.
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Flúor , Triazóis , Triazóis/química , Flúor/química , Halogênios/química , Peptídeos , EletrônicaRESUMO
The behaviour of a Frank-like chemical network model featuring autocatalytic production of chiral enantiomers from achiral reactants is studied numerically in 1D and 2D systems using fluctuating initial conditions and accounting for diffusion processes. Our results reveal that the achiral substrate concentration can play an ambivalent role. It is shown that when the achiral reactant concentration is maintained constant and homogeneous in 1D systems, global homochirality is not systematically reached when the size of the system or the achiral reactant concentration are increased. However, with a fixed concentration gradient, coexisting homochiral domains of opposite handedness are no longer observed and homogeneous homochirality, i.e. the presence of a single stable homochiral domain, is recovered. In 2D systems, reaching global homochirality is just a matter of time. This time is dramatically increased when insufficient or excessive amount of achiral reactant is used. An optimal amount of achiral material is observed to maximise the enantiomer production rates.
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Resistance to anticancer drugs is a complex process that results from alterations in drug targets; development of alternative pathways for growth activation; changes in cellular pharmacology, including increased drug efflux; regulatory changes that alter differentiation pathways or pathways for response to environmental adversity; and/or changes in the local physiology of the cancer, such as blood supply, tissue hydrodynamics, behavior of neighboring cells, and immune system response. All of these specific mechanisms are facilitated by the intrinsic hallmarks of cancer, such as tumor cell heterogeneity, redundancy of growth-promoting pathways, increased mutation rate and/or epigenetic alterations, and the dynamic variation of tumor behavior in time and space. Understanding the relative contribution of each of these factors is further complicated by the lack of adequate in vitro models that mimic clinical cancers. Several strategies to use current knowledge of drug resistance to improve treatment of cancer are suggested.
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Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias/tratamento farmacológico , Animais , Sistemas de Liberação de Medicamentos/métodos , Humanos , Neoplasias/genéticaRESUMO
The natural regeneration of tree species depends on seed and pollen dispersal. To assess whether limited dispersal could be critical for the sustainability of selective logging practices, we performed parentage analyses in two Central African legume canopy species displaying contrasted floral and fruit traits: Distemonanthus benthamianus and Erythrophleum suaveolens. We also developed new tools linking forward dispersal kernels with backward migration rates to better characterize long-distance dispersal. Much longer pollen dispersal in D. benthamianus (mean distance dp = 700 m, mp = 52% immigration rate in 6 km2 plot, s = 7% selfing rate) than in E. suaveolens (dp = 294 m, mp = 22% in 2 km2 plot, s = 20%) might reflect different insect pollinators. At a local scale, secondary seed dispersal by vertebrates led to larger seed dispersal distances in the barochorous E. suaveolens (ds = 175 m) than in the wind-dispersed D. benthamianus (ds = 71 m). Yet, seed dispersal appeared much more fat-tailed in the latter species (15%-25% seeds dispersing >500 m), putatively due to storm winds (papery pods). The reproductive success was correlated to trunk diameter in E. suaveolens and crown dominance in D. benthamianus. Contrary to D. benthamianus, E. suaveolens underwent significant assortative mating, increasing further the already high inbreeding of its juveniles due to selfing, which seems offset by strong inbreeding depression. To achieve sustainable exploitation, seed and pollen dispersal distances did not appear limiting, but the natural regeneration of E. suaveolens might become insufficient if all trees above the minimum legal cutting diameter were exploited. This highlights the importance of assessing the diameter structure of reproductive trees for logged species.
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Fabaceae/crescimento & desenvolvimento , Pólen/crescimento & desenvolvimento , Reprodução/genética , Dispersão de Sementes/genética , Fabaceae/genética , Frutas/genética , Frutas/crescimento & desenvolvimento , Fluxo Gênico , Genética Populacional , Endogamia , Repetições de Microssatélites/genética , Polinização/genética , Reprodução/fisiologia , Sementes/genética , Árvores/genética , Árvores/crescimento & desenvolvimento , VentoRESUMO
OBJECTIVE: The aim was to evaluate the distribution of the diameter of the great saphenous vein (GSV) at mid-thigh level and to investigate its association with clinical class, symptoms, and proximal extent of reflux. METHODS: Vascular physicians, members of the French Society of Phlebology, were invited to participate in a consecutive observational study in patients presenting with symptoms and/or signs of uni- or bilateral chronic venous disorders (CVDs) in previously untreated limbs (clinical class of the CEAP classification C0s - C6). Patients were included between January and March 2015. They completed a specially designed venous symptoms questionnaire. Duplex ultrasound of the included limbs was performed with the patient standing to detect reflux in the GSV and to measure the GSV inner diameter at mid-thigh. RESULTS: Between January and March 2015, 35 physicians examined 1245 patients (2450 limbs after excluding 40 limbs): 77% were female, mean age 52 ± 14; 69% of the patients had venous symptoms in one or both legs. The most frequent symptoms were feeling of heaviness, feeling of swelling and aching. Predominant CEAP clinical classes were C2 (38% of limbs) and C1 (35%). In case of GSV reflux (40% of limbs), the average diameter was 5.6 ± 2 mm and the distribution was 62% < 6 mm, 30% between 6 and 8 mm, and 8% > 8 mm. The study showed a clear association between clinical class and GSV diameter (the higher the clinical class, the larger the diameter; p < .0001), between venous symptoms and diameter (the larger the diameter, the higher the intensity of symptoms, p < .0001 for overall discomfort) and between proximal extent of reflux and diameter (the more proximal the extent of reflux, the larger the diameter, p < .0001). CONCLUSION: The DIAGRAVES study demonstrated that in France for patients consulting with CVDs, more than half of the incompetent GSVs had a diameter < 6 mm, while large diameters were relatively infrequent. This should be kept in mind when considering management strategies in patients with CVDs.
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Veia Safena , Ultrassonografia Doppler Dupla/métodos , Insuficiência Venosa , Anatomia Regional , Doença Crônica , Feminino , França/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Seleção de Pacientes , Veia Safena/diagnóstico por imagem , Veia Safena/patologia , Veia Safena/fisiopatologia , Índice de Gravidade de Doença , Procedimentos Cirúrgicos Vasculares/métodos , Insuficiência Venosa/diagnóstico , Insuficiência Venosa/epidemiologia , Insuficiência Venosa/fisiopatologia , Insuficiência Venosa/cirurgiaRESUMO
Crystallography and quantum mechanics have always been tightly connected because reliable quantum mechanical models are needed to determine crystal structures. Due to this natural synergy, nowadays accurate distributions of electrons in space can be obtained from diffraction and scattering experiments. In the original definition of quantum crystallography (QCr) given by Massa, Karle and Huang, direct extraction of wavefunctions or density matrices from measured intensities of reflections or, conversely, ad hoc quantum mechanical calculations to enhance the accuracy of the crystallographic refinement are implicated. Nevertheless, many other active and emerging research areas involving quantum mechanics and scattering experiments are not covered by the original definition although they enable to observe and explain quantum phenomena as accurately and successfully as the original strategies. Therefore, we give an overview over current research that is related to a broader notion of QCr, and discuss options how QCr can evolve to become a complete and independent domain of natural sciences. The goal of this paper is to initiate discussions around QCr, but not to find a final definition of the field.
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In this paper, we propose a simple cluster model with limited basis sets to reproduce the unpaired electron distributions in a YTiO3 ferromagnetic crystal. The spin-resolved one-electron-reduced density matrix is reconstructed simultaneously from theoretical magnetic structure factors and directional magnetic Compton profiles using our joint refinement algorithm. This algorithm is guided by the rescaling of basis functions and the adjustment of the spin population matrix. The resulting spin electron density in both position and momentum spaces from the joint refinement model is in agreement with theoretical and experimental results. Benefits brought from magnetic Compton profiles to the entire spin density matrix are illustrated. We studied the magnetic properties of the YTiO3 crystal along the Ti-O1-Ti bonding. We found that the basis functions are mostly rescaled by means of magnetic Compton profiles, while the molecular occupation numbers are mainly modified by the magnetic structure factors.
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Despite improvements in the management of liver cancer, the survival rate for patients with hepatocellular carcinoma (HCC) remains dismal. The survival benefit of systemic chemotherapy for the treatment of liver cancer is only marginal. Although the reasons for treatment failure are multifactorial, intrinsic resistance to chemotherapy plays a primary role. Here, we analyzed the expression of 377 multidrug resistance (MDR)-associated genes in two independent cohorts of patients with advanced HCC, with the aim of finding ways to improve survival in this poor-prognosis cancer. Taqman-based quantitative polymerase chain reaction revealed a 45-gene signature that predicts overall survival (OS) in patients with HCC. Using the Connectivity Map Tool, we were able to identify drugs that converted the gene expression profiles of HCC cell lines from ones matching patients with poor OS to profiles associated with good OS. We found three compounds that convert the gene expression profiles of three HCC cell lines to gene expression profiles associated with good OS. These compounds increase histone acetylation, which correlates with the synergistic sensitization of those MDR tumor cells to conventional chemotherapeutic agents, including cisplatin, sorafenib, and 5-fluorouracil. Our results indicate that it is possible to modulate gene expression profiles in HCC cell lines to those associated with better outcome. This approach also increases sensitization of HCC cells toward conventional chemotherapeutic agents. This work suggests new treatment strategies for a disease for which few therapeutic options exist.
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Antineoplásicos/uso terapêutico , Carcinoma Hepatocelular/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/genética , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/mortalidade , Linhagem Celular Tumoral , Estudos de Coortes , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/mortalidade , Taxa de Sobrevida/tendências , Resultado do TratamentoRESUMO
The presence of water has been shown to deeply impact the stability and geometry of Zn complexes in solution. Evidence for tetra- and penta-coordinated species in a pyridylmethylamine-Zn(II) model complex is presented. Novel (1) Hâ NMR tools such as T1 -filtered selective exchange spectroscopy and pure shifted gradient-encoded selective refocusing as well as classical 2D ((1) H-(1) H) exchange spectroscopy, diffusion-ordered spectroscopy and T1 ((1) H) measurements, in combination with density functional theory methods allow the full conformational dynamics of a pyridylmethylamine-Zn(II) complex to be revealed. Four conformers and two families of complexes depending on the hydration states are elucidated.
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Multidrug resistance (MDR) has been associated with expression of ABC transporter genes including P-glycoprotein (Pgp, MDR1, ABCB1). However, deregulation of apoptotic pathways also renders cells resistant to chemotherapy. To discover apoptosis-related genes affected by Pgp expression, we used the HeLa MDR-off system. We found that using doxycycline to control Pgp expression has a significant advantage over tetracycline, in that doxycycline caused less endogenous gene expression modification/perturbation, and was more potent than tetracycline in suppressing Pgp expression. Cells overexpressing Pgp have lower TNFSF10 (TRAIL) expression than their parental cells. Controlled downregulation of Pgp increased endogenous TRAIL protein expression. Also, ectopic overexpression of TRAIL in Pgp-positive cells was associated with a reduction in Pgp levels. However, cells expressing a functionally defective mutant Pgp showed an increase in TRAIL expression, suggesting that Pgp function is required for TRAIL suppression. Cells in which Pgp is knocked down by upregulation of TRAIL expression are less susceptible to TRAIL ligand (sTRAIL)-induced apoptosis. Our findings reveal an inverse correlation between functional Pgp and endogenous TRAIL expression. Pgp function plays an important role in the TRAIL-mediated apoptosis pathway by regulating endogenous TRAIL expression and the TRAIL-mediated apoptosis pathway in MDR cancer cells.
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Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Apoptose/genética , Resistencia a Medicamentos Antineoplásicos/genética , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/biossíntese , Linhagem Celular Tumoral , Regulação para Baixo , Doxiciclina/farmacologia , Resistência a Múltiplos Medicamentos/genética , Células HeLa , Humanos , Interferência de RNA , RNA Interferente Pequeno , Ligante Indutor de Apoptose Relacionado a TNF/biossíntese , Tetraciclina/farmacologiaRESUMO
BACKGROUND: We know very little about the genetic factors affecting susceptibility to drug-induced central nervous system (CNS) toxicities, and this has limited our ability to optimally utilize existing drugs or to develop new drugs for CNS disorders. For example, haloperidol is a potent dopamine antagonist that is used to treat psychotic disorders, but 50% of treated patients develop characteristic extrapyramidal symptoms caused by haloperidol-induced toxicity (HIT), which limits its clinical utility. We do not have any information about the genetic factors affecting this drug-induced toxicity. HIT in humans is directly mirrored in a murine genetic model, where inbred mouse strains are differentially susceptible to HIT. Therefore, we genetically analyzed this murine model and performed a translational human genetic association study. METHODS AND FINDINGS: A whole genome SNP database and computational genetic mapping were used to analyze the murine genetic model of HIT. Guided by the mouse genetic analysis, we demonstrate that genetic variation within an ABC-drug efflux transporter (Abcb5) affected susceptibility to HIT. In situ hybridization results reveal that Abcb5 is expressed in brain capillaries, and by cerebellar Purkinje cells. We also analyzed chromosome substitution strains, imaged haloperidol abundance in brain tissue sections and directly measured haloperidol (and its metabolite) levels in brain, and characterized Abcb5 knockout mice. Our results demonstrate that Abcb5 is part of the blood-brain barrier; it affects susceptibility to HIT by altering the brain concentration of haloperidol. Moreover, a genetic association study in a haloperidol-treated human cohort indicates that human ABCB5 alleles had a time-dependent effect on susceptibility to individual and combined measures of HIT. Abcb5 alleles are pharmacogenetic factors that affect susceptibility to HIT, but it is likely that additional pharmacogenetic susceptibility factors will be discovered. CONCLUSIONS: ABCB5 alleles alter susceptibility to HIT in mouse and humans. This discovery leads to a new model that (at least in part) explains inter-individual differences in susceptibility to a drug-induced CNS toxicity.
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Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/genética , Alelos , Encéfalo/metabolismo , Haloperidol/toxicidade , Síndromes Neurotóxicas/genética , Polimorfismo de Nucleotídeo Único , Subfamília B de Transportador de Cassetes de Ligação de ATP , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo , Adolescente , Adulto , Animais , Antipsicóticos/toxicidade , Barreira Hematoencefálica/metabolismo , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Adulto JovemRESUMO
To identify molecular determinants of histone deacetylase inhibitor (HDI) resistance, we selected HuT78 cutaneous T-cell lymphoma (CTCL) cells with romidepsin in the presence of P-glycoprotein inhibitors to prevent transporter upregulation. Resistant sublines were 250- to 385-fold resistant to romidepsin and were resistant to apoptosis induced by apicidin, entinostat, panobinostat, belinostat, and vorinostat. A custom TaqMan array identified increased insulin receptor (INSR) gene expression; immunoblot analysis confirmed increased protein expression and a four- to eightfold increase in mitogen-activated protein kinase (MAPK) kinase (MEK) phosphorylation in resistant cells compared with parental cells. Resistant cells were exquisitely sensitive to MEK inhibitors, and apoptosis correlated with restoration of proapoptotic Bim. Romidepsin combined with MEK inhibitors yielded greater apoptosis in cells expressing mutant KRAS compared with romidepsin treatment alone. Gene expression analysis of samples obtained from patients with CTCL enrolled on the NCI1312 phase 2 study of romidepsin in T-cell lymphoma suggested perturbation of the MAPK pathway by romidepsin. Immunohistochemical analysis of Bim expression demonstrated decreased expression in some skin biopsies at disease progression. These findings implicate increased activation of MEK and decreased Bim expression as a resistance mechanism to HDIs, supporting combination of romidepsin with MEK inhibitors in clinical trials.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Proteínas Reguladoras de Apoptose/genética , Depsipeptídeos/administração & dosagem , Resistencia a Medicamentos Antineoplásicos/genética , Inibidores de Histona Desacetilases/uso terapêutico , Linfoma Cutâneo de Células T/tratamento farmacológico , Sistema de Sinalização das MAP Quinases/fisiologia , Proteínas de Membrana/genética , Inibidores de Proteínas Quinases/administração & dosagem , Proteínas Proto-Oncogênicas/genética , Proteínas Reguladoras de Apoptose/metabolismo , Proteína 11 Semelhante a Bcl-2 , Ensaios Clínicos Fase II como Assunto , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Avaliação Pré-Clínica de Medicamentos , Resistencia a Medicamentos Antineoplásicos/fisiologia , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Inibidores de Histona Desacetilases/administração & dosagem , Humanos , Linfoma Cutâneo de Células T/genética , Linfoma Cutâneo de Células T/metabolismo , MAP Quinase Quinase 1/antagonistas & inibidores , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteínas de Membrana/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas Proto-Oncogênicas/metabolismo , Racionalização , Transcriptoma , Células Tumorais CultivadasRESUMO
BACKGROUND: Emergency department (ED) crowding has been linked with adverse medical events. However, this association was inadequately controlled for potential confounding variables. OBJECTIVES: To investigate whether ED crowding is independently associated with risk of in-hospital death and morbidity, and longer total hospital stay. METHODS: Prospective observational cohort study of all patients (≥ 18 years) presenting to the ED of an academic teaching hospital in Leuven, Belgium from June 21, 2010 to July 20, 2012. Multivariate logistic regression and proportional hazard analysis was used to control for risk factors. ED occupancy was determined for 108,229 included patients and labeled "ED crowding" when occupancy was within the highest quartile of occupancy. Outcomes within 10 days of ED admission included in-hospital death, hospital-acquired morbidities, and total hospital stay. RESULTS: During ED crowding, a median of 58 (interquartile range 55-63) patients were present for 40 licensed treatment bays. After controlling for all baseline risk factors and as compared with the lowest quartile of ED occupancy (30 [26-32] patients), ED crowding was not independently associated with mortality (odds ratio [OR] 0.94, 95% confidence interval [CI] 0.74-1.19; p = 0.6), but tended to be associated with higher incidence of hospital-acquired pneumonia (OR 1.24, 95% CI 0.96-1.62; p = 0.09). CONCLUSIONS: Failing to control for baseline risk factors may have led to false-positive associations between ED crowding and mortality in previous studies. After controlling for risk factors, we showed that ED crowding was associated with longer hospital stays but not with increased mortality.
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Aglomeração , Serviço Hospitalar de Emergência/organização & administração , Mortalidade Hospitalar , Morbidade , Adolescente , Adulto , Bélgica/epidemiologia , Feminino , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de RiscoRESUMO
The System for Continuous Observation of Rodents in Home-cage Environment (SCORHE) was developed to demonstrate the viability of compact and scalable designs for quantifying activity levels and behavior patterns for mice housed within a commercial ventilated cage rack. The SCORHE in-rack design provides day- and night-time monitoring with the consistency and convenience of the home-cage environment. The dual-video camera custom hardware design makes efficient use of space, does not require home-cage modification, and is animal-facility user-friendly. Given the system's low cost and suitability for use in existing vivariums without modification to the animal husbandry procedures or housing setup, SCORHE opens up the potential for the wider use of automated video monitoring in animal facilities. SCORHE's potential uses include day-to-day health monitoring, as well as advanced behavioral screening and ethology experiments, ranging from the assessment of the short- and long-term effects of experimental cancer treatments to the evaluation of mouse models. When used for phenotyping and animal model studies, SCORHE aims to eliminate the concerns often associated with many mouse-monitoring methods, such as circadian rhythm disruption, acclimation periods, lack of night-time measurements, and short monitoring periods. Custom software integrates two video streams to extract several mouse activity and behavior measures. Studies comparing the activity levels of ABCB5 knockout and HMGN1 overexpresser mice with their respective C57BL parental strains demonstrate SCORHE's efficacy in characterizing the activity profiles for singly- and doubly-housed mice. Another study was conducted to demonstrate the ability of SCORHE to detect a change in activity resulting from administering a sedative.
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Comportamento Animal/efeitos dos fármacos , Abrigo para Animais , Hipnóticos e Sedativos/farmacologia , Gravação em Vídeo/métodos , Adaptação Psicológica , Animais , Ritmo Circadiano , Desenho Assistido por Computador , Camundongos , Camundongos Endogâmicos C57BL , Modelos AnimaisRESUMO
ABCB5, an ATP-binding cassette (ABC) transporter, is highly expressed in melanoma cells, and may contribute to the extreme resistance of melanomas to chemotherapy by efflux of anti-cancer drugs. Our goal was to determine whether we could functionally express human ABCB5 in the model yeast Saccharomyces cerevisiae, in order to demonstrate an efflux function for ABCB5 in the absence of background pump activity from other human transporters. Heterologous expression would also facilitate drug discovery for this important target. DNAs encoding ABCB5 sequences were cloned into the chromosomal PDR5 locus of a S. cerevisiae strain in which seven endogenous ABC transporters have been deleted. Protein expression in the yeast cells was monitored by immunodetection using both a specific anti-ABCB5 antibody and a cross-reactive anti-ABCB1 antibody. ABCB5 function in recombinant yeast cells was measured by determining whether the cells possessed increased resistance to known pump substrates, compared to the host yeast strain, in assays of yeast growth. Three ABCB5 constructs were made in yeast. One was derived from the ABCB5-ß mRNA, which is highly expressed in human tissues but is a truncation of a canonical full-size ABC transporter. Two constructs contained full-length ABCB5 sequences: either a native sequence from cDNA or a synthetic sequence codon-harmonized for S. cerevisiae. Expression of all three constructs in yeast was confirmed by immunodetection. Expression of the codon-harmonized full-length ABCB5 DNA conferred increased resistance, relative to the host yeast strain, to the putative substrates rhodamine 123, daunorubicin, tetramethylrhodamine, FK506, or clorgyline. We conclude that full-length ABCB5 can be functionally expressed in S. cerevisiae and confers drug resistance.
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Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Melanoma/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Subfamília B de Transportador de Cassetes de Ligação de ATP , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Clorgilina/farmacologia , Daunorrubicina/farmacologia , Humanos , Rodamina 123/farmacologia , Rodaminas/farmacologia , Saccharomyces cerevisiae/genética , Tacrolimo/farmacologiaRESUMO
Although in vitro models have been a cornerstone of anti-cancer drug development, their direct applicability to clinical cancer research has been uncertain. Using a state-of-the-art Taqman-based quantitative RT-PCR assay, we investigated the multidrug resistance (MDR) transcriptome of six cancer types, in established cancer cell lines (grown in monolayer, 3D scaffold, or in xenograft) and clinical samples, either containing >75% tumor cells or microdissected. The MDR transcriptome was determined a priori based on an extensive curation of the literature published during the last three decades, which led to the enumeration of 380 genes. No correlation was found between clinical samples and established cancer cell lines. As expected, we found up-regulation of genes that would facilitate survival across all cultured cancer cell lines evaluated. More troubling, however, were data showing that all of the cell lines, grown either in vitro or in vivo, bear more resemblance to each other, regardless of the tissue of origin, than to the clinical samples they are supposed to model. Although cultured cells can be used to study many aspects of cancer biology and response of cells to drugs, this study emphasizes the necessity for new in vitro cancer models and the use of primary tumor models in which gene expression can be manipulated and small molecules tested in a setting that more closely mimics the in vivo cancer microenvironment so as to avoid radical changes in gene expression profiles brought on by extended periods of cell culture.