854 research outputs found
Casein kinase 1 family proteins promote Slimb-dependent Expanded degradation
Hippo signalling integrates diverse stimuli related to epithelial architecture to regulate tissue growth and cell fate decisions. The Hippo kinase cascade represses the growth-promoting transcription co-activator Yorkie. The FERM protein Expanded is one of the main upstream Hippo signalling regulators i
Bioenergetic dysfunction in Huntington's disease human cybrids
In this work we studied the mitochondrial-associated metabolic pathways in Huntington's disease (HD) versus control (CTR) cybrids, a cell model in which the contribution of mitochondrial defects from patients is isolated. HD cybrids exhibited an interesting increase in ATP levels, when compared to CTR cybrids. Concomitantly, we observed increased glycolytic rate in HD cybrids, as revealed by increased lactate/pyruvate ratio, which was reverted after inhibition of glycolysis. A decrease in glucose-6-phosphate dehydrogenase activity in HD cybrids further indicated decreased rate of the pentose-phosphate pathway. ATP levels of HD cybrids were significantly decreased under glycolysis inhibition, which was accompanied by a decrease in phosphocreatine. Nevertheless, pyruvate supplementation could not recover HD cybrids' ATP or phosphocreatine levels, suggesting a dysfunction in mitochondrial use of that substrate. Oligomycin also caused a decrease in ATP levels, suggesting a partial support of ATP generation by the mitochondria. Nevertheless, mitochondrial NADH/NAD(t) levels were decreased in HD cybrids, which was correlated with a decrease in pyruvate dehydrogenase activity and protein expression, suggesting decreased tricarboxylic acid cycle (TCA) input from glycolysis. Interestingly, the activity of alpha-ketoglutarate dehydrogenase, a critical enzyme complex that links the TCA to amino acid synthesis and degradation, was increased in HD cybrids. In accordance, mitochondrial levels of glutamate were increased and alanine was decreased, whereas aspartate and glutamine levels were unchanged in HD cybrids. Conversely, malate dehydrogenase activity from total cell extracts was unchanged in HD cybrids. Our results suggest that inherent dysfunction of mitochondria from HD patients affects cellular bioenergetics in an otherwise functional nuclear background
Flow structure beneath periodic waves with constant vorticity under normal electric fields
Waves with constant vorticity and electrohydrodynamics flows are two topics in fluid dynamics that have attracted much attention from scientists for both the mathematical challenge and their industrial applications. The coupling of electric fields and vorticity is of significant research interest. In this paper, we study the flow structure of steady periodic travelling waves with constant vorticity on dielectric fluid under the effect of normal electric fields. Through the conformal mapping technique combined with pseudo-spectral numerical methods, we develop an approach that allows us to conclude that the flow can have zero, two or three stagnation points according to variations in the voltage potential. We describe in detail the recirculation zones that emerge together with the stagnation points. Besides, we show that the number of local maxima of the pressure on the bottom boundary is intrinsically connected to the saddle points
Mitochondrial-dependent apoptosis in Huntington's disease human cybrids
We investigated the involvement of mitochondrial-dependent apoptosis in Huntington's disease (HD) vs. control (CTR) cybrids, obtained from the fusion of human platelets with mitochondrial DNA-depleted NT2 cells, and further exposed to 3-nitropropionic acid (3-NP) or staurosporine (STS). Untreated HD cybrids did not exhibit significant modifications in the activity of mitochondrial respiratory chain complexes I-IV or in mtDNA sequence variations suggestive of a primary role in mitochondrial susceptibility in the subpopulation of HD carriers studied. However, a slight decrease in mitochondrial membrane potential and increased formation of intracellular hydroperoxides was observed in HD cybrids under basal conditions. Furthermore, apoptotic nuclei morphology and a moderate increase in caspase-3 activation, as well as increased levels of superoxide ions and hydroperoxides were observed in HD cybrids upon 3-NP or STS treatment. 3-NP-evoked apoptosis in HD cybrids involved cytochrome c and AIF release from mitochondria, which was associated with mitochondrial Bax translocation. CTR cybrids subjected to 3-NP showed increased mitochondrial Bax and Bim levels and the release of AIF, but not cytochrome c, suggesting a different mode of cell death, linked to the loss of membrane integrity. Additionally, increased mitochondrial Bim and Bak levels, and a slight release of cytochrome c in untreated HD cybrids may help to explain their moderate susceptibility to mitochondrial-dependent apoptosi
Interventions for physical activity promotion applied to the primary healthcare settings for people living in regions of low socioeconomic level: study protocol for a non-randomized controlled trial.
BACKGROUND: Regular physical activity practice has been widely recommended for promoting health, but the physical activity levels remain low in the population. Therefore, the study of interventions to promote physical activity is essential. OBJECTIVE: To present the methodology of two physical activity interventions from the "Ambiente Ativo" ("Active Environment") project. METHODS: 12-month non-randomized controlled intervention trial. 157 healthy and physically inactive individuals were selected: health education (nâ=â54) supervised exercise (nâ=â54) and control (nâ=â49). Intervention based on health education: a multidisciplinary team of health professionals organized the intervention in group discussions, phone calls, SMS and educational material. Intervention based on supervised exercise program: consisted of offering an exercise program in groups supervised by physical education professionals involving strength, endurance and flexibility exercises. The physical activity level was assessed by the International Physical Activity Questionnaire (long version), physical activities recalls, pedometers and accelerometers over a seven-day period. RESULT: This study described two different proposals for promoting physical activity that were applied to adults attended through the public healthcare settings. The participants were living in a region of low socioeconomic level, while respecting the characteristics and organization of the system and its professionals, and also adapting the interventions to the realities of the individuals attended. CONCLUSION: Both interventions are applicable in regions of low socioeconomic level, while respecting the social and economic characteristics of each region. TRIAL REGISTRATION: ClinicalTrials.gov NCT01852981
Evidence-based radiography : a new methodology or the systematisation of an old practice?
Introduction: Evidence based radiography (EBR) is the logical development of
evidence based practice applied to radiography. The aim of this study was to
investigate the opinion of a cohort of Portuguese radiographers in Southern Portugal
working in public hospitals regarding evidence based practice (EBP), namely about the
levels of knowledge about EBR, how they access information and how they use it
within daily practice.
Methods: A self-administered questionnaire was applied to a sample of 40
radiographers in the Portuguese region of Algarve. This questionnaire was validated for
Portuguese speakers using the translation-retranslation method.
Results: The final response rate was 69% (40/58). Results suggest that most
radiographers trained EBR during their undergraduate training. Although, no
statistically significant correlations were found in the practice of EBR against participant
gender, age, training, career level, reading papers and workplace. The most frequent
reason to read papers is the âinterestâ to do so, and national professional journals are
read more often. It was found that radiographers that read scientific papers more
frequently know more about research (p=0.005), understand the importance of
research for the professional activity (p=0.023), and know more on how to conduct
research papers (p=0.034).
Conclusion: EBR within radiography is not yet well established, and radiographersâ
have varying viewpoints. Radiographers that read scientific papers more frequently
understand better the philosophy behind this concept but it is very important to deepen
the knowledge on this area.
Implications for Practice: When practicing radiography based on the best available
scientific knowledge, professionals are ensuring the best for patients and for
profession. To achieve this, and before taking any action, it is important to evaluate the
current situation, and this research presents a way to do so
Chagas Cardiomiopathy: The Potential of Diastolic Dysfunction and Brain Natriuretic Peptide in the Early Identification of Cardiac Damage
Chagas disease remains a major cause of morbidity and mortality in several
countries of Latin America and has become a potential public health problem in
countries where the disease is not endemic as a result of migration flows.
Cardiac involvement represents the main cause of mortality, but its diagnosis is
still based on nonspecific criteria with poor sensitivity. Early identification
of patients with cardiac damage is desirable, since early treatment may improve
prognosis. Diastolic dysfunction and elevated brain natriuretic peptide levels
are present in different cardiomyopathies and in advanced phases of Chagas
disease. However, there are scarce data about the role of these parameters in
earlier forms of the disease. We conducted a study to assess the diastolic
function, regional systolic abnormalities and brain natriuretic peptide levels
in the different forms of Chagas disease. The main finding of our investigation
is that diastolic dysfunction occurs before any cardiac dilatation or motion
abnormality. In addition, BNP levels identify patients with diastolic
dysfunction and Chagas disease with high specificity. The results reported in
this study could help to early diagnose myocardial involvement and better
stratify patients with Chagas disease
Mitochondrial echoes of first settlement and genetic continuity in El Salvador
Background: From Paleo-Indian times to recent historical episodes, the Mesoamerican isthmus played an important role in the distribution and patterns of variability all around the double American continent. However, the amount of genetic information currently available on Central American continental populations is very scarce. In order to shed light on the role of Mesoamerica in the peopling of the New World, the present study focuses on the analysis of the mtDNA variation in a population sample from El Salvador.
Methodology/Principal Findings: We have carried out DNA sequencing of the entire control region of the mitochondrial DNA (mtDNA) genome in 90 individuals from El Salvador. We have also compiled more than 3,985 control region profiles from the public domain and the literature in order to carry out inter-population comparisons. The results reveal a predominant Native American component in this region: by far, the most prevalent mtDNA haplogroup in this country (at ~90%) is A2, in contrast with other North, Meso- and South American populations. Haplogroup A2 shows a star-like phylogeny and is very diverse with a substantial proportion of mtDNAs (45%; sequence range 16090â16365) still unobserved in other American populations. Two different Bayesian approaches used to estimate admixture proportions in El Salvador shows that the majority of the mtDNAs observed come from North America. A preliminary founder analysis indicates that the settlement of El Salvador occurred about 13,400Âą5,200 Y.B.P.. The founder age of A2 in El Salvador is close to the overall age of A2 in America, which suggests that the colonization of this region occurred within a few thousand years of the initial expansion into the Americas.
Conclusions/Significance: As a whole, the results are compatible with the hypothesis that today's A2 variability in El Salvador represents to a large extent the indigenous component of the region. Concordant with this hypothesis is also the observation of a very limited contribution from European and African women (~5%). This implies that the Atlantic slave trade had a very small demographic impact in El Salvador in contrast to its transformation of the gene pool in neighbouring populations from the Caribbean facade
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