Implication of AMPK in glucose-evoked modulation of Na,K-ATPase

Background and aims: Na,K-ATPase is an integral membrane protein that maintains the gradients of Na+ and K+, using the energy of ATP hydrolysis, maintaining the ionic gradients that allow electrical activity to occur. It has been demonstrated that, in pancreatic β-cells, Na,K-ATPase is regulated by glucose and that this phenomenon is impaired in glucose intolerant subjects. However, the mechanism underlying glucose-induced modulation of Na,K-ATPase is still unclear. The AMP-activated protein kinase (AMPK) is a molecular key player in energy homeostasis, providing exquisite sensitivity to small changes in intracellular AMP levels and thus to intracellular [ATP]/[ADP] ratio, that is known to activate protein regulatory pathways. Since in pancreatic β-cell, glucose has marked effects on oxidative metabolism and total intracellular ATP and AMP levels, the involvement of AMPK in the cascade of events regulating Na,K-ATPase regulation in pancreatic β-cells was postulated. The aim of this work was to evaluate the putative role of AMPK in the glucose-evoked regulation of Na,K-ATPase activity in the pancreatic β-cell. Materials and methods: Pancreatic -cells from normal (control) or glucose-intolerant Wistar rats (GIR) were isolated and cultured (48h). Cell batches were pre-incubated (30min) with 2.1mM glucose to reach basal activity. Afterwards cells were challenged to 8.4mM glucose for 20min, in the presence or absence of AMPK agonists (AICAR) and antagonists (compound C; CC). ATPase activity was assessed in intact cells by colorimetric quantification of Pi formed in 30min. Na,K-ATPase activity was calculated by the difference between the activities obtained in the absence and in presence the of 1mM ouabain. Results: In basal conditions the activity of Na,K-ATPase from normal and GIR pancreatic β-cell was similar (0.184±0.030 and 0.186±0.020 molPi/min/mgProt, respectively). Challenging the control β-cells with glucose 8.4mM evoked a 62% reduction of Na,K-ATPase activity whereas in GIR β-cells a significantly lower inhibition (40%) was observed. The addition of AICAR 1mM abolished glucose-induced Na,K-ATPase inhibition (0,166±0.011 molPi/min/mg). In control β-cell, the addition of CC 10 μM had no effect on glucose-induced inhibition of Na,K-ATPase. In the contrary, in GIR β-cells it significantly potentiated glucose-evoked inhibition of Na,K-ATPase reaching values similar to that observed in the controls (66%). Conclusions: The AMPK agonist AICAR counteracts the inhibitory action of glucose on Na,K-ATPase of control β-cells whereas CC amplified the glucose-induced inhibition of Na,K-ATPase in GIR β-cells. These results suggest that AMPK plays a central role in the cascade of events underlying glucose-induced modulation of Na,K-ATPase and that the defect must be upstream of AMPK. Finally, abnormal glucose-induced regulation of Na,K-ATPase occurs prior to overt type 2 diabetes and might be a feature in the disease development

Abnormal regulation of Na,K-ATPase in Glucose Intolerant Rats.

Introduction: Glucose is the most important physiological insulin secretagogue. However, the mechanisms underlying glucose-induced insulin release are not fully understood. The role of electrogenic systems such as ionic pumps, to these events remains essentially uninvestigated. Na,K-ATPase, responsible for maintaining Na+ and K+ gradients across the plasma membrane and generates a net outward current, thus changes in its activity may contribute to the early ionic events regulating insulin secretion (Therien and Blostein, 2000). Objective: The aim of this work was to evaluate the regulation of Na,K-ATPase activity by glucose in intact -cells of normal and glucose intolerant (GI) rats and its putative contribution to the regulation of insulin secretion. Material and Methods: Pancreatic -cells, from normal or control or GI rats, were isolated and cultured (48h). Cell batches were pre-incubated (30min) with 2mM glucose to reach basal. Afterwards cells were challenged with glucose in the interval 0-11mM for 60min, for dose-dependence evaluation, or with 8mM glucose for 5-120min, for time-dependence evaluation. ATPase activity was assessed in intact cells by colorimetric quantification of Pi formed in 30min. Na,K-ATPase activity was calculated by the difference between the activities obtained in the absence and in presence the of 1mM ouabain (Costa et al., 2009). Results: In β-cells from normal rats, glucose induced a bimodal regulation of Na,K-ATPase. In the absence of glucose, Na,K-ATPase activity was 0.056±0.015 U/mg. Stimulation with 2mM glucose induced an increase of Na,K-ATPase activity of ~4 fold whereas for [glucose] above 2mM it was observed a significant inhibition of Na,K-ATPase activity (0.061±0.013, 0.080±0.009 and 0.064±0.005 U/mg for 5.6, 8.4 and 11mM glucose, respectively, compared to 0.188±0.035 U/mg observed in 2mM G; n=3-8). β-cells from GI rats does not present this profile; in the absence of glucose, Na,K-ATPase activity was 0.202±0.036 U/mg and no significant differences from this value were observed with the other glucose concentration tested. Addicionally, in β-cells from normal rats, glucose (8mM) induced a time-dependent inhibition, with a biphasic profile, of Na,K-ATPase - it was observed a decrease in the pump activity between 0 and 20min stimulation where it reached a minimum value (77%). For incubation periods over 20min, the pump activity slowly and partially recovered (54%, 55% and 52%, for 30, 60 and 120min, respectively; n=7). In β-cells from GI animals, an less accentuated decrease of Na,K-ATPase activity between 0 ans 20min was also observed (34%), and is not observed further recover in activity. Conclusions: This work demonstrates there Na,K-ATPase is strictly regulated by glucose in pancreatic β-cell. This regulation is unpaired in GI animals. Na,K-ATPase contribution to glucose-induced ionic events and insulin secretion might be relevant and must be explored as a possible therapeutic target in TD2 . 1. Therien AG, Blostein R (2000) Mechanisms of sodium pump regulation. Am J Physiol Cell Physiol 279:C541-C566 2. Costa AR, Real J, Antunes CM, Cruz-Morais J (2009) A new approach for determination of Na,K-ATPase activity: application to intact pancreatic beta-cells. In Vitro Cell Dev Biol Ani

A IMPORTÂNCIA DO ENFERMEIRO NA GESTÃO DOS RESÍDUOS HOSPITALARES

A produção de resíduos hospitalares tem vindo a aumentar, significativamente, tanto em quantidade, diversidade como na perigosidade, que consequentemente representam um grave problema à saúde ocupacional, pública e ambiental, e ainda mais quando o seu destino final não é apropriado. Uma vez que os resíduos perigosos apresentam riscos, tanto a curto como a longo prazo, para pessoas, e para o meio ambiente, a avaliação e gestão dos riscos é muito importante para conhecer os níveis de exposição destes resíduos. Tendo em conta a classificação dos resíduos, estes foram classificados de acordo com a OMS e da legislação de Cabo Verde que classifica-os em resíduos equiparados aos urbanos, resíduos hospitalares não perigosos, resíduos hospitalares de risco biológico e resíduos hospitalares específicos, de forma a facilitar a gestão correcta, controlando e diminuindo os riscos, alcançando a redução da quantidade desde origem até o destino final.Este trabalho serve para elucidar desde os profissionais de saúde às autoridades competentes, sobre os perigos existentes aquando da gestão inadequada dos resíduos hospitalares e o seu impacto para a saúde. O objectivo geral deste trabalho é analisar a importância que os enfermeiros têm na gestão adequada dos resíduos hospitalares. Como recurso metodologia, fez-se o levantamento bibliográfico, consultas a legislação de Cabo Verde para compreender conceitos e como estão classificados a nível nacional. Como fonte secundário de informação fez-se a revisão sistemática de literatura e posteriormente a discussão dos artigos analisados.Os resultados da pesquisa indicam que a separação na origem e o encaminhamento à reciclagem, reduzem o volume de resíduos destinados ao aterro sanitário, levando a benefícios ambientais e sociais, e, em alguns casos, recursos financeiros para o estabelecimento de saúde. Os ploblemas relacionados à gestão dos resíduos hospitalares estão directamente ligados à conscientização de funcionários, enfermeiros, médicos e gerência dos estabelecimentos de saúde, da importância da correcta separação, armazenamento e manuseio desses resíduos; além da falta de recursos e espaços físicos. É necessário uma maior mobilização por parte dos estabelecimentos de saúde para a discussão da legislação e de soluções de problemas, com acções concretas guiadas por objectivos e metas a serem alcançadas, compatíveis com a realidade dos hospitais

The ERK 1 and 2 Pathway in the Nervous System: From Basic Aspects to Possible Clinical Applications in Pain and Visceral Dysfunction

The extracellular signal-regulated kinases 1 and 2 (ERK) cascade, member of the mitogen-activated protein kinases superfamily of signalling pathways, is one of the best characterized pathways as many protein interactions and phosphorylation events have been systematically studied. Traditionally, ERK are associated with the regulation of proliferation and differentiation as well as survival of various cell types. Their activity is controlled by phosphorylation on specific aminoacidic residues, which is induced by a variety of external cues, including growth-promoting factors

Digital art, sustainability and design thinking: study of a case in higher education

After a brief overview on the relationship between art and sustainability, in this paper we present a practical case that illustrates the potential of using design thinking in raising awareness towards environmental sustainability in the context of Higher Education. We describe the phases in the application of design thinking by a group of students, and evaluate the impact of this procedure on their vision regarding the relationship between art and nature, and their motivation to find artistic solutions with an impact on society.info:eu-repo/semantics/publishedVersio

Metabolic processes of green tea in diabetes mellitus type 2

info:eu-repo/semantics/publishedVersio

Biomarkers in the Overactive Bladder Syndrome

Environmental managemen

New Instruments for Impact Assessment: study of an academic library

This study presents a review of new instruments for the impact assessment of libraries and a case study of the evaluation impact of the Library of the Faculty of Science, University of Porto (FCUP), from the students’ point of view. We con ducted a mixed methods research, i.e., which includes both qualitative data, to describe characteristics, in particular human actions, and quantitative data, represented by numbers that indicate exact amounts which can be statistically manipulated. Applying International Standard ISO16439:2014 (E) - Information and documentation - Methods and procedures for assessing the impact of libraries, we collected, 20 opinion texts from students of different nationalities, published in «Notícias da Biblioteca», from January 2013 to December 2014 and have conducted seven interviews.Research work carried out within the scope of UID/HIS/00057/2013 (POCI-01-0145-FEDER-007702), FCT/Portugal, COMPETE, FEDER, Portugal2020