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1.
J Healthc Leadersh ; 16: 93-104, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38440078

RESUMO

Background: Despite the large amount of leadership and implementation theories and recommendations, healthcare services continue to struggle with efficiently incorporating new knowledge. The questioning of conventional leadership approaches in healthcare organizations prompted us to investigate how frontline leaders comprehend their own implementation intentions and actions, and how these intentions and actions may impact the implementation of clinical guidelines in mental healthcare in Norway. Methods: Employing a theory-driven qualitative design, we conducted nine semi-structured interviews with frontline leaders who had recently led implementation of clinical guidelines for the treatment of psychosis in mental health. We employed Systematic Text Condensation, informed by Normalization Process Theory, to structure and analyze the data and used fidelity scales to measure the degree of implementation and distinguish between leaders' levels of success in implementation. Results: Frontline leaders in units that achieved high success in implementation described their intentions and actions differently, from those with less success. The former group's actions aligned more closely with the constructs of the Normalization Process Theory compared to the latter group when describing their actions. Frontline leaders leading units with a high degree of implementation success describe relation-orientation, trust, and providing adaptive space for staff members to take initiative. In contrast, those leading units with less implementation success describe more control and guidance of co-operators and place more emphasize on information and knowledge. Conclusion: Differences in how frontline leaders describe their actions and intentions to achieve clinical guideline implementation suggest that the leadership approach of these frontline leaders is an important factor to consider when planning and conducting implementation. To better understand the implementation process, it is important to pay attention to how frontline leaders customize their leadership approaches to the dynamics of complex organizations, and how they interact with their team and superiors.

2.
J Safety Res ; 86: 174-184, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37718044

RESUMO

INTRODUCTION: Speaking up about safety issues, termed "safety voice," is a proactive response where people across all levels of the organization express their concerns to prevent physical hazards. An understanding of safety voice requires insight into its antecedents. A perceived need to fit in with the organization and fear of consequences can trump the courage to speak out about safety concerns. Safety voice climate can be seen as a manifestation of the social exchanges in an organization and functions as a roadmap of which speaking out behaviors are encouraged and which behaviors are not. This study conceptualizes safety voice climate, presents the Safety Voice Climate Scale (SVCS) as a measurement tool, and gathers initial evidence for its validity. The study also assesses the associations between the SVCS and safety voice behavior. METHOD: The SVCS and the measurement of safety voice behavior were derived from the Trends in Risk Level in the Norwegian Petroleum Activity questionnaire. The SVCS includes the two theoretical dimensions Work colleagues' encouragement of safety voice and Leaders' attitudes towards safety voice. Psychometric properties were tested with a representative sample from the Norwegian petroleum sector (n = 7,624). RESULTS: Confirmatory factor analyses supported the proposed two-factor model, and the internal consistency of the factors was good. Furthermore, a structural equation model including the SVCS as predictors of safety voice behavior showed a good fit, indicating acceptable criterion validity, although only the Work colleagues' encouragement of safety voice variable was significantly associated with safety voice behavior. Conclusion and practical application: The SVCS can be used as a tool to detect some of the barriers and supporting elements relating to safety voice and guidance on the efforts needed to foster work climates that promote communication of safety issues.


Assuntos
Comunicação , Petróleo , Humanos , Psicometria , Análise Fatorial , Medo
3.
Front Psychol ; 14: 1082283, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37089726

RESUMO

Introduction: Creativity is vital for competitive advantage within technological environments facing the fourth industrial revolution. However, existing research on creativity has rarely addressed how a climate beneficial for worker psychological health, a psychosocial safety climate (PSC), could additionally stimulate the growth of workplace creativity, innovation, and performance in digital environments. Method: To examine how individually perceived PSC influences subsequent work engagement promoting higher levels of computer-based radical and incremental creativity, innovation, and work performance, employees in a software engineering firm (N = 29, 86 observations) completed a weekly questionnaire for 4 consecutive weeks. Results: At the between-person level PSC was positively related to average future weekly individual fluctuations of creativity (radical and incremental), work engagement, and job performance. Additionally weekly work engagement was related to future creativity (radical and incremental). Work engagement also mediated the between-person relationship between PSC and future creativity (both radical and incremental). PSC did not predict innovation. Discussion: This study contributes to the theory on PSC, creativity, and work performance by elucidating the individual perceived PSC-creativity relationship and suggesting PSC systems as meaningful antecedents to digital work performance.

4.
Evid Based Toxicol ; 1(1): 1-15, 2023 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-38264543

RESUMO

This protocol describes the design and development of a tool for evaluation of the internal validity of in vitro studies, which is needed to include the data as evidence in systematic reviews and chemical risk assessments. The tool will be designed specifically to be applied to cell culture studies, including, but not restricted to, studies meeting the new approach methodology (NAM) definition. The tool is called INVITES-IN (IN VITro Experimental Studies INternal validity). In this protocol, three of the four studies that will be performed to create the release version of INVITES-IN are described. In the first study, evaluation of existing assessment tools will be combined with focus group discussions to identify how characteristics of the design or conduct of an in vitro study can affect its internal validity. Bias domains and items considered to be of relevance for in vitro studies will be identified. In the second study, group agreement on internal validity domains and items of importance for in vitro studies will be identified via a modified Delphi methodology. In the third study, the draft version of the tool will be created, based on the data on relevance and importance of bias domains and items collected in Studies 1 and 2. A separate protocol will be prepared for the fourth study, which includes the user testing and validation of the tool, and collection of users' experience.

5.
EFSA J ; 20(Suppl 2): e200917, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36531271

RESUMO

Risk and risk-benefit assessments of food are complex exercises, in which access to and use of several disconnected individual stand-alone databases is required to obtain hazard and exposure information. Data obtained from such databases ideally should be in line with the FAIR principles, i.e. the data must be Findable, Accessible, Interoperable and Reusable. However, often cases are encountered when one or more of these principles are not followed. In this project, we set out to assess if existing commonly used databases in risk assessment are in line with the FAIR principles. We also investigated how access, interoperability and reusability of data could be improved. We used the OpenFoodTox and the Seafood database as examples and showed how commonly used freely available open-source tools and repositories can be implemented in the data extraction process of risk assessments to increase data reusability and crosstalk across different databases.

6.
J Health Organ Manag ; ahead-of-print(ahead-of-print)2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-35253414

RESUMO

PURPOSE: The purpose of this study was to explore and interpret how frontline leaders define, experience and rationalise their approaches to the successful implementation of clinical guidelines in mental health care. DESIGN/METHODOLOGY/APPROACH: Employing an interpretative phenomenological design, the authors conducted and analysed individual interviews of frontline leaders at 14 psychiatric clinics involved in a national study of implementing evidence-based clinical guidelines in mental health. FINDINGS: The authors found a broad spectrum of attitudes and attributes, as well as a wide repertoire of strategies for frontline implementation leadership. Three main approaches were revealed, comprising "Curious and welcoming", "Integrity and setting standards" and "Caring and collegial". RESEARCH LIMITATIONS/IMPLICATIONS: The study present what experienced frontline leaders emphasise to enable implementation of guidelines, not empirical pieces of evidences for what they in fact do or if these actions lead to implementation. The generalisability to other settings is unknown. Another sample profile, context or organisational level may have impacted the result. The concreteness of the frontline leaders' considerations, approaches and actions gives important knowledge about frontline leaders leadership across traditional leadership theories. ORIGINALITY/VALUE: Existing leadership theories describe different leadership styles, while this study reveals the need for a wide range of approaches to balance the many needs and demands. The complexity of leadership approaches this study found is in line with implementation theories; thus, the present study incorporates implementation science into the leadership literature.


Assuntos
Liderança , Serviços de Saúde Mental , Humanos , Saúde Mental , Noruega , Pesquisa Qualitativa
7.
Food Res Int ; 137: 109499, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33233144

RESUMO

Chemical contaminants are present in all foods. Data on the occurrence of contaminants in foods that are often consumed or contain high contaminant concentrations are critical for the estimation of exposure and evaluation of potential negative health effects. Due to limited resources for the monitoring of contaminants and other chemical substances in foods, methods for prioritisation are needed. We have developed a straightforward semi-quantitative method to rank chemical substances in foods for monitoring as part of a risk-based food control. The method is based on considerations of toxicity, level of exposure including both occurrence in food and dietary intake, vulnerability of one or more population groups due to high exposure because of special food habits or resulting from specific genetic variants, diseases, drug use or age/life stages, and the adequacy of both toxicity and exposure data. The chemical substances ranked for monitoring were contaminants occurring naturally, unintentionally or incidentally in foods or formed during food processing, and the inclusion criteria were high toxicity, high exposure and/or lack of toxicity or exposure data. In principle, this method can be used for all classes of chemical substances that occur in foods, both unintended contaminants and deliberately added chemical substances. Foods considered relevant for monitoring of the different chemical substances were also identified. The outcomes of ranking exercises using the new method including considerations of vulnerable groups and adequacy of data and a shortened version based on risk considerations only were compared. The results showed that the resolution between the contaminants was notably increased with the extended method, which we considered as advantageous for the ranking of chemical substances for monitoring in foods.


Assuntos
Manipulação de Alimentos
8.
PLoS One ; 13(7): e0199558, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30020966

RESUMO

Observed associations between consumption of diet foods and obesity have sparked controversy over whether intense sweeteners may promote weight gain, despite their negligible energy contribution. We conducted a scoping review of reviews, to obtain an overview of hypotheses, research approaches and features of the evidence on intense sweeteners' potential relationships to appetite and weight changes. We searched for reviews of the scientific literature published from 2006 to May 2017. Two reviewers independently assessed title and abstracts, and full text publications. Arksey and O'Malley's framework for scoping reviews guided the process. We extracted and charted data on characteristics of the reviews and the evidence presented. The 40 included reviews present hypotheses both on how intense sweeteners can reduce or maintain body weight and on how these can promote weight gain. We classified only five publications as systematic reviews; another nine presented some systematic approaches, while 26 reviews did not describe criteria for selecting or assessing the primary studies. Evidence was often presented for intense sweeteners as a group or unspecified, and against several comparators (e.g. sugar, water, placebo, intake levels) with limited discussion on the interpretation of different combinations. Apart from the observational studies, the presented primary evidence in humans is dominated by small studies with short follow-up-considered insufficient to assess weight change. Systematic reviews of animal studies are lacking in this topic area. The systematic evidence only partly explore forwarded hypotheses found in the literature. Primary studies in humans seem to be available for systematic exploration of some hypotheses, but long-term experimental studies in humans appear sparse. With few exceptions, the reviews on intense sweeteners and weight change underuse systematic methodology, and thus, the available evidence. Further studies and systematic reviews should be explicit about the hypothesis explored and elucidate possible underlying mechanisms.


Assuntos
Apetite/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Edulcorantes/farmacologia , Humanos , Vigilância em Saúde Pública
9.
Int J Dev Neurosci ; 55: 82-90, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27769911

RESUMO

Immediate early gene nerve growth factor-induced clone B (NGFI-B), a nuclear receptor important for differentiation and apoptosis, is expressed in mice and rat cerebellum from an early stage of postnatal development. Following apoptotic stimuli NGFI-B translocates to mitochondria to initiate cell death processes. Controlled cell death is critical for correct cerebellar development. Immunohistochemical analysis of NGFI-B in sections of mice cerebella showed NGFI-B to be expressed in granule neurons in vivo at a time (P8-11) when apoptosis is known to occur. The importance of NGFI-B for apoptosis of cultured rat cerebellar granule neurons was investigated by inducing apoptosis with calcium ionophore A23187 (CaI, 0.1µM). Imaging studies of gfp-tagged NGFI-B confirmed that mitochondrial translocation of NGFI-B occurred following treatment with CaI and was reduced by addition of 9-cis-retinoic acid (1µM), a retinoid X receptor (RXR) agonist that prevents dimerization of RXR and NGFI-B that is known to occur before translocation. Consequently, 9-cis-retinoic acid partly reduced cell death. To address the causality of NGFI-B in apoptosis further, knock-down by siRNA was performed and it removed 85% of the NGFI-B protein. This resulted in a complete inhibition of apoptosis after CaI exposure. Together these findings suggest that NGFI-B plays a role in controlling correct cerebellar development.


Assuntos
Apoptose/efeitos dos fármacos , Cálcio/farmacologia , Cerebelo/citologia , Cerebelo/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Neurônios/efeitos dos fármacos , Análise de Variância , Animais , Animais Recém-Nascidos , Calcimicina/farmacologia , Ionóforos de Cálcio/farmacologia , Movimento Celular/fisiologia , Citarabina/farmacologia , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Técnicas In Vitro , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/administração & dosagem , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Wistar , Receptores X de Retinoides/metabolismo , Estatísticas não Paramétricas , Fatores de Tempo , Transfecção
10.
Clin Oral Investig ; 19(1): 61-9, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24615298

RESUMO

OBJECTIVES: Due to incomplete curing and material degradation, cells in the oral cavity may be exposed to monomers and filler particles from dental composite fillings. The objective of the present study was to investigate if combined exposures to particles and a methacrylate monomer from composite fillings resulted in additive effects on the macrophage immune response. MATERIAL AND METHODS: Two filler particles, Nanosilica (12 nm) and Quartz (1 µm), were studied at concentrations 0.5-4 µg/cm(2), while the methacrylate monomer triethyleneglycol dimethacrylate (TEGDMA) was applied at 5 and 50 µM. RAW 264.7 macrophages were exposed to monomers and/or particles for 24 h, with a subsequent 24 h combined exposure to monomers and/or particles and the bacterial factor lipopolysaccharide (LPS) to stimulate an immune response. Release of the pro-inflammatory cytokines interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) were measured as well as the cellular viability. RESULTS: Co-exposure to Nanosilica and Quartz resulted in an additive attenuation of the LPS-induced IL-1ß release. Moreover, co-exposure to TEGDMA and both types of filler particles also resulted in an additive attenuation, although with a weak synergistic trend. The cellular viability and TNF-α release were not significantly affected by the exposures. CONCLUSION: The present findings emphasize the necessity of considering effects of combined exposure to dental degradation products in future risk assessments. CLINICAL RELEVANCE: Attenuated cytokine release could have implications for the macrophage immune response and result in impaired bacterial clearance. Further studies are necessary to determine implications for formation of dental biofilms and caries development.


Assuntos
Macrófagos/imunologia , Polietilenoglicóis/toxicidade , Ácidos Polimetacrílicos/toxicidade , Animais , Sobrevivência Celular/efeitos dos fármacos , Interleucina-1beta/imunologia , Lipopolissacarídeos , Camundongos , Microscopia Eletrônica de Varredura , Nanopartículas/toxicidade , Quartzo/toxicidade , Células RAW 264.7 , Dióxido de Silício/toxicidade , Fator de Necrose Tumoral alfa/imunologia
11.
Int J Dev Neurosci ; 31(8): 762-9, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24091367

RESUMO

In mice, prenatal exposure to low doses of bisphenol A has been shown to affect neurogenesis and neuronal migration in cortex, resulting in disturbance of both neuronal positioning and the network formation between thalamus and cortex in the offspring brain. In the present study we investigated whether prenatal exposure to bisphenol A disturbs the neurodevelopment of the cerebellum. Two different model systems were used; offspring from two strains of mice from mothers receiving bisphenol A in the drinking water before mating, during gestation and lactation, and chicken embryos exposed to bisphenol A (in the egg) on embryonic day 16 for 24h before preparation of cerebellar granule cell cultures. In the cerebellum, tight regulation of the level of transcription factor Pax6 is critical for correct development of granule neurons. During the development, the Pax6 level in granule neurons is high when these cells are located in the external granule layer and during their migration to the internal granule layer, and it is then reduced. We report that bisphenol A induced an increase in the thickness of the external granule layer and also an increase in the total cerebellar Pax6 level in 11 days old mice offspring. In cultured chicken cerebellar granule neurons from bisphenol A injected eggs the Pax6 level was increased day 6 in vitro. Together, these findings indicate that bisphenol A may affect the granule neurons in the developing cerebellum and thereby may disturb the correct development of the cerebellum.


Assuntos
Compostos Benzidrílicos/toxicidade , Cerebelo , Estrogênios não Esteroides/toxicidade , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Fenóis/toxicidade , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Fatores Etários , Animais , Depressores do Sistema Nervoso Central/farmacologia , Cerebelo/efeitos dos fármacos , Cerebelo/crescimento & desenvolvimento , Cerebelo/patologia , Embrião de Galinha , Galinhas , Relação Dose-Resposta a Droga , Comportamento de Ingestão de Líquido/efeitos dos fármacos , Etanol/farmacologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos NOD , Neurônios/metabolismo , Neurônios/patologia , Gravidez , Efeitos Tardios da Exposição Pré-Natal/patologia
12.
Eur J Pharmacol ; 703(1-3): 25-32, 2013 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-23416212

RESUMO

Cancer cells are more sensitive to oxidative stress due to higher levels of reactive oxygen species. Therefore, the ability of anti-cancer agent combretastatin A-4 (CA-4) and triazole analogues to induce reactive oxygen species may be important for selectivity against cancer cells. The purpose of the present study was to investigate the structural requirements for reactive oxygen species production by CA-4 and the triazole analogues Ana-2, Ana-3 and Ana-4. Ana-2 and Ana-3 mimic the cis configuration in CA-4; Ana-3 lacks the phenolic hydroxyl group, while Ana-4 mimics a trans configuration. The rat pheochromocytoma cancer cell line PC12 was used as model system. CA-4 and Ana-2 were highly toxic; Ana-3 was less toxic, whereas Ana-4 was non-toxic. The probe dihydroethidium detected reactive oxygen species production from CA-4, Ana-2, and Ana-3. CA-4 and Ana-2 also induced oxidation of the reactive oxygen species probe dihydrorhodamine and activation of caspase-3. Thus, the phenolic hydroxyl group in CA-4 and Ana-2 was necessary for dihydrorhodamine oxidation, caspase-3 activation, and increased cytotoxicity.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Bibenzilas/farmacologia , Caspase 3/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Triazóis/farmacologia , Animais , Caspase 9/metabolismo , Morte Celular/efeitos dos fármacos , Células PC12 , Ratos
13.
Toxicol Lett ; 216(2-3): 130-8, 2013 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-23182953

RESUMO

Methacrylate monomers have been identified in aqueous extracts of freshly cured dental fillings. The hypothesis tested presently was that low concentrations of triethyleneglycol dimethacrylate (TEGDMA) and 2-hydroxyethyl methacrylate (HEMA) alone or in combination interfere with the LPS-induced release of cytokines from the macrophage cell line RAW264.7. The cells were exposed to 5-200 µM of monomers for 24 h followed by a 24 h combined exposure to monomers and LPS. TEGDMA reduced LPS-induced release of interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α), whereas HEMA only reduced IL-1ß release. Co-exposure to the two monomers indicated an additive effect. Moreover, the reduced cytokine release persisted for 24 h after termination of the monomer exposure. The LPS-induced activation of proteins in pre-transcriptional signaling pathways (CD14, p-ERK1/2, p-p38, p-JNK, p-IκB-α and p-NFκB-p65) was not altered by monomer exposure, neither were the levels of IL-1ß and TNF-α mRNA. However, the LPS-induced level of pro-IL-1ß was decreased by the monomer treatment. Thus, HEMA and TEGDMA may interfere with post-transcriptional regulation of synthesis and release of these cytokines. Overall, the results suggest that low concentrations of monomers may cause impaired macrophage responses, and that these effects can persist for up to 24 h after exposure.


Assuntos
Interleucina-1beta/imunologia , Lipopolissacarídeos/antagonistas & inibidores , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Metacrilatos/farmacologia , Polietilenoglicóis/farmacologia , Ácidos Polimetacrílicos/farmacologia , Fator de Necrose Tumoral alfa/imunologia , Animais , Western Blotting , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Interleucina-1beta/metabolismo , Lipopolissacarídeos/farmacologia , Macrófagos/metabolismo , Camundongos , RNA/química , RNA/genética , Resinas Sintéticas/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/imunologia
14.
Neurochem Int ; 61(1): 79-88, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22525717

RESUMO

NGFI-B (NR4A1, Nur77 or TR3) together with Nurr1 (NR4A2) and NOR-1 (NR4A3) constitute the NR4A subgroup of orphan nuclear receptors. They play critical roles in proliferation, differentiation, survival and apoptosis in different cell types, including neurons, immature T-cells, and different cancer cells. As ligand-independent and constitutively active receptors, the diverse biological activities of NGFI-B, Nurr1 and NOR-1 depend on their levels of expression, post-translational modifications and subcellular localization. Nuclear localization of the NR4A proteins leads to transcriptional activity, whereas NGFI-B and recently also NOR-1 have been shown to induce apoptosis by a more direct mechanism when localized at mitochondria. In the present study we investigated mRNA expression and subcellular translocation of the NR4A proteins during glutamate excitotoxicity in rat cerebellar granule neurons. NGFI-B and Nurr1 mRNA, but not NOR-1 mRNA, were induced by treatments associated with calcium influx, although their regulation seemed to be different. NR4A(gfp) fusion proteins showed a predominant nuclear localization in untreated cells. After glutamate treatment NGFI-B(gfp) translocated to cytosol and mitochondria within a few hours, whereas Nurr1(gfp) translocation was delayed, and NOR-1(gfp) mainly stayed in the nucleus. Subcellular targeting of NGFI-B seems to be tightly regulated, as a single mutation of threonine 142 altered NGFI-B(gfp) localization. Differences in expression and subcellular translocation of NGFI-B, Nurr1, and NOR-1 may reflect different functions in neurons in glutamate excitotoxicity.


Assuntos
Núcleo Celular/metabolismo , Citoplasma/metabolismo , Proteínas de Ligação a DNA/metabolismo , Ácido Glutâmico/farmacologia , Proteínas do Tecido Nervoso/metabolismo , Neurônios/efeitos dos fármacos , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Animais , Sequência de Bases , Western Blotting , Cálcio/metabolismo , Primers do DNA , Proteínas de Ligação a DNA/genética , Masculino , Proteínas do Tecido Nervoso/genética , Neurônios/metabolismo , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , RNA Mensageiro/genética , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real
15.
Toxicol Lett ; 209(1): 43-50, 2012 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-22143055

RESUMO

Epidemiological studies have associated indoor phthalate exposure with increased incidences and severity of asthma in children and adults, and inflammatory effects have been suggested as a possible mechanism. Recent studies report that phthalates may activate mitogen-activated protein (MAP) kinase p38 and various peroxisome proliferator-activated receptor (PPAR) isoforms. Here we confirm and extend these findings by investigating possible signalling pathways activated in the murine monocyte-macrophage cell line RAW264.7, using mono-2-ethylhexylphthalate (MEHP) as a model compound. MEHP exposure (0.3-1.0 mM) for 3h increased tumour necrosis factor (TNF)-α release and changed the cellular morphology into elongated spindle-like appearance, resembling more differentiated anti-inflammatory macrophages (M2). This was accompanied by increased expression of the macrophage differentiation marker CD163. Western analysis showed phosphorylation of p38 and Akt after 30 min exposure. Experiments using specific inhibitors suggested that MEHP-induced activation of both p38 and the phosphoinositide-3 (PI3) kinase/Akt pathway were involved in the release of TNF-α; whereas only PI3kinase seemed to be involved in differentiation. In contrast, inhibitors of PPARα and γ reduced differentiation, but did not affect TNF-α release. In conclusion, MEHP induced cytokine release and triggered differentiation of RAW264.7 cells, possibly into M2-like macrophages, but different signalling pathways appear to be involved in these responses.


Assuntos
Dietilexilftalato/análogos & derivados , Macrófagos/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismo , Animais , Western Blotting , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Dietilexilftalato/farmacologia , Imuno-Histoquímica , Camundongos , Microscopia de Fluorescência , Proteína Oncogênica v-akt/metabolismo , PPAR alfa/antagonistas & inibidores , PPAR gama/antagonistas & inibidores , Fosfatidilinositol 3-Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo
16.
Biochem Biophys Res Commun ; 414(1): 90-5, 2011 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-21945431

RESUMO

Nuclear receptor and apoptosis inducer NGFI-B translocates out of the nucleus as a heterodimer with RXR in response to different apoptosis stimuli, and therefore represents a potential pharmacological target. We found that the cytosolic levels of NGFI-B and RXRα were increased in cultures of cerebellar granule neurons 2h after treatment with glutamate (excitatory neurotransmitter in the brain, involved in stroke). To find a time-window for potential intervention the neurons were transfected with gfp-tagged expressor plasmids for NGFI-B and RXR. The default localization of NGFI-Bgfp and RXRgfp was nuclear, however, translocation out of the nucleus was observed 2-3h after glutamate treatment. We therefore hypothesized that the time-window between treatment and translocation would allow late protection against neuronal death. The RXR ligand 9-cis retinoic acid was used to arrest NGFI-B and RXR in the nucleus. Addition of 9-cis retinoic acid 1h after treatment with glutamate reduced the cytosolic translocation of NGFI-B and RXRα, the cytosolic translocation of NGFI-Bgfp observed in live neurons, as well as the neuronal death. However, the reduced translocation and the reduced cell death were not observed when 9-cis retinoic acid was added after 3h. Thus, late protection from glutamate induced death by addition of 9-cis retinoic acid is possible in a time-window after apoptosis induction.


Assuntos
Apoptose/efeitos dos fármacos , Citoproteção , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Receptor X Retinoide alfa/metabolismo , Tretinoína/farmacologia , Alitretinoína , Animais , Células Cultivadas , Ácido Glutâmico/toxicidade , Ligantes , Neurônios/metabolismo , Ratos
17.
J Neurosci Methods ; 193(1): 39-46, 2010 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-20727911

RESUMO

Transfection is a useful tool for studying molecular signalling pathways. However, neurons have proven hard to transfect. In the present paper we have optimized a new electroporation procedure using the Cellaxess(®) system for transient transfection of adherent primary neurons from chicken (Gallus gallus) and compared it to a liposome based procedure using Metafectene(®) Pro. In order to evaluate the two methods, glucocorticoid receptor (GR) function was chosen as a test. GRs are expressed in high amounts in the cerebellum. GR is regulated by another nuclear receptor (NGFI-B, the first member found in the NR4A family). We first showed that forskolin and phorbol ester activated an NR4A-dependent reporter gene indicating that members of the NR4A nuclear receptor family are present endogenously and upregulated by external stimuli. Then, transfected NGFI-B was shown to antagonize the dexamethasone-activated transcriptional activation by endogenous GR, leading to the conclusion that NR4A-family members are important modulators of GR mediated regulatory processes in the cerebellum, as in other cell types. Both transfection methods proved useful. While the electroporation technique yielded small rings with many transfected cells optimal for microscopy studies, the liposome based method resulted in transfected cells evenly distributed in the dish rendering this method well suited for biochemical studies.


Assuntos
Cerebelo/metabolismo , Eletroporação/métodos , Neurônios/metabolismo , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Receptores de Glucocorticoides/genética , Transfecção/métodos , Análise de Variância , Animais , Células Cultivadas , Cerebelo/citologia , Galinhas , Neurônios/citologia , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Receptores de Glucocorticoides/metabolismo
18.
Toxicol Mech Methods ; 19(3): 214-8, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19730755

RESUMO

4-methylimidazole (4MeI) is a tremorogenic and convulsive agent of concern both in human and veterinary toxicology. The in vitro effects of 4MeI (5 microM-20 mM) on cerebral glutamate decarboxylase (GAD) activity and (in concentrations up to 50 mM) on binding of [(3)H]GABA to cerebral GABA receptors were tested in brain tissue from B6D2 mice. The effects of 1-methylimidazole (1MeI), 2-methylimidazole (2MeI), 4-methylhydroxy-imidazole (4MeOHI), imidazole-4-acetic acid (4AcI) (all in concentrations of 5-20 mM) and imidazole (20 mM) on GAD activity were also tested. In addition, the effect of a lethal dose of 4MeI (250 mg/kg ip) to B6D2 mice in vivo on the postmortem concentrations of gamma-aminobutyric acid (GABA) and glutamate in their brains were measured. In all experiments, student's t-test was used for statistical comparison. 4MeI in concentrations of 2 mM and above did inhibit GAD activity significantly in vitro, but glutamate and GABA concentrations in mouse brains after lethal 4MeI poisoning were not significantly different from control values. The effect of 2MeI on GAD activity was stronger than the effect of 4MeI. Binding of [(3)H]GABA to cerebral GABA receptors in vitro was significantly inhibited only at 4MeI concentrations of 5 mM and above. The results indicate that neither inhibition of GABA synthesis nor competitive inhibition of the binding of GABA to its receptors are likely mechanisms for the excitation and convulsions seen in 4MeI poisoning in animals.


Assuntos
Encéfalo/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Glutamato Descarboxilase/antagonistas & inibidores , Imidazóis/farmacologia , Animais , Encéfalo/enzimologia , Encéfalo/metabolismo , Camundongos , Sinaptossomos/metabolismo , Ácido gama-Aminobutírico/metabolismo
19.
Scand J Psychol ; 49(1): 59-68, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18190403

RESUMO

The aim of this study was to explore the occurrence of bullying in the restaurant sector and its potential consequences. The sample consisted of 207 superiors and employees in 70 restaurants. The findings indicated that bullying prevails in the restaurant industry, with apprentices as a risk group. Bullying was negatively related to job satisfaction, commitment, employees' perceptions of creative behavior, and external evaluations of restaurant creativity level, and positively related to burnout and intention to leave the job. Some support was found for a mediation hypothesis, where bullying was the predictor, job satisfaction, commitment and burnout were mediators, and intention to leave was dependent variable. One implication of this study is that there is a need to challenge the attitude, common in this sector, that aggression and bullying is a natural and even necessary part of the work environment.


Assuntos
Agressão/psicologia , Restaurantes/estatística & dados numéricos , Transtornos do Comportamento Social/epidemiologia , Comportamento Social , Adulto , Esgotamento Profissional , Feminino , Humanos , Intenção , Satisfação no Emprego , Masculino , Prevalência , Inquéritos e Questionários
20.
Brain Res ; 1153: 43-51, 2007 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-17462609

RESUMO

In this study the role of mitochondrial secretory PLA2-IIA in glutamate-induced cell death in cultured cerebellar granule neurons has been investigated. Inhibition of secretory PLA2-IIA blocked glutamate-induced cell death. Since PLA2 may generate reactive oxygen species (ROS), we have investigated ROS production, detected as dihydrorhodamine 123 oxidation and nitrotyrosine modifications of proteins, following glutamate treatment in the absence or presence of an inhibitor of secretory PLA2-IIA. There was an increased generation of ROS in both glutamate- and buffer-treated neurons compared to untreated neurons. Scavenging with dihydrorhodamine 123 reduced glutamate-induced death (60%), showing that ROS detected in glutamate-treated neurons were associated with cell death. However, ROS detected in buffer-treated neurons were not associated with toxicity. Glutamate treatment led to ROS production predominantly in peripheral mitochondria, whereas buffer treatment led to ROS production in somal mitochondria. Inhibition of secretory PLA2-IIA (i) reduced the generation of ROS after glutamate treatment, (ii) reduced the ROS production in peripheral mitochondria in glutamate-treated neurons, consistent with the fact that calcium entry through glutamate (NMDA) receptors has a privileged access to peripheral mitochondria, and (iii) did not reduce the generation of ROS after buffer treatment. In conclusion, activation of NMDA receptors induces ROS, which is critical for neuronal death, due to secretory PLA2-IIA associated with peripheral mitochondria.


Assuntos
Fosfolipases A2 do Grupo II/metabolismo , Mitocôndrias/metabolismo , Neurônios/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Análise de Variância , Animais , Animais Recém-Nascidos , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Células Cultivadas , Cerebelo/citologia , Maleato de Dizocilpina/farmacologia , Interações Medicamentosas , Inibidores Enzimáticos/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Ácido Glutâmico/farmacologia , Mitocôndrias/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/ultraestrutura , Ratos
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