310 research outputs found
Science Communication: Synthesis of Research Findings and Practical Advice from Experienced Communicators
Use of effective public communication strategies is critical for Extension professionals to successfully navigate challenges faced by the agriculture sector and local community, effect policy changes, and ensure public value for the Extension program. Simply addressing the public knowledge deficit is ineffective for gaining public trust in science. Thus, implementation of public engagement and increased dialogue are central to contemporary Extension practice. Such an approach requires balancing factual knowledge with an engaging and open communication style. We draw on both research findings and advice from experienced science communicators to provide a synthesis of practical tips for achieving this balance. Guidance is given regarding framing, word choices, and common pitfalls
Erythrocytes as regulators of blood vessel tone
A drop in oxygen partial pressure results in elevation of blood vessel diameter. It has been demonstrated that isolated vessels exhibit this unique feature only when they are perfused in the presence of erythrocytes. More recently, it was shown that haemoglobin plays a key role in oxygen sensing. Its deoxygenated form interacts with band 3 protein, triggering the cascade of non-identified intracellular signals involved in nitric oxide production and release of ATP interacting with P2Y purinergic receptors in endothelial cells. In this review, we summarize the data on mechanisms of ATP release from erythrocytes, as well as on its physiological and pathophysiological implications
Revision of the Late Devonian ptyctodonts (Vertebrata, Placodermi) from southern Poland
New studies on Frasnian ptyctodonts, including the revision of historic material in addition to the description of new material, have resulted in the detailed description of two species of Ptyctodus (Ptyctodus obliquus, Ptyctodus kielcensis), eight indeterminate specimens of Ptyctodus sp. from the Holy Cross Mountains and two specimens from DÄbnik near Kraków, four indeterminate specimens of Rhynchodus sp., and two specimens of Ptyctodontidae gen. et sp. indet. from the Holy Cross Mountains. One of the described species (P. kielcensis) appears to be endemic for the Holy Cross Mountains region. Based on general knowledge of the Frasnian stratigraphy of the Holy Cross Mountains and on the conodont material obtained from the fragments of the sediments attached to specimens, it was possible to define the predetermined subdivision of the Frasnian as ranges of conodonts and the fauna to be placed within conodont zones. Previously only antiarchs, bottom-feeding placoderms, had been recovered from the Lower and Upper Kellwasser horizons from this area (PÅucki); thus, the occurrence of ptyctodonts represents an additional placoderm taxon. This work describes the first placoderm remains from DÄbnik near Kraków, which also represent the first described placoderms from an area other than the Holy Cross Mountains
Modulation of Extracellular ATP Content of Mast Cells and DRG Neurons by Irradiation: Studies on Underlying Mechanism of Low-Level-Laser Therapy
Low-level-laser therapy (LLLT) is an effective complementary treatment, especially for anti-inflammation and wound healing in which dermis or mucus mast cells (MCs) are involved. In periphery, MCs crosstalk with neurons via purinergic signals and participate in various physiological and pathophysiological processes. Whether extracellular ATP, an important purine in purinergic signaling, of MCs and neurons could be modulated by irradiation remains unknown. In this study, effects of red-laser irradiation on extracellular ATP content of MCs and dorsal root ganglia (DRG) neurons were investigated and underlying mechanisms were explored in vitro. Our results show that irradiation led to elevation of extracellular ATP level in the human mast cell line HMC-1 in a dose-dependent manner, which was accompanied by elevation of intracellular ATP content, an indicator for ATP synthesis, together with [Ca2+]i elevation, a trigger signal for exocytotic ATP release. In contrast to MCs, irradiation attenuated the extracellular ATP content of neurons, which could be abolished by ARL 67156, a nonspecific ecto-ATPases inhibitor. Our results suggest that irradiation potentiates extracellular ATP of MCs by promoting ATP synthesis and release and attenuates extracellular ATP of neurons by upregulating ecto-ATPase activity. The opposite responses of these two cell types indicate complex mechanisms underlying LLLT
TELESSAÚDE: NOVOS CAMINHOS NA ATENÇÃO À SAÚDE FRENTE À INFECÇÃO PELO NOVO CORONAVÍRUS
A infecção pelo novo coronavírus tem como uma de suas principais medidas preventivas o distanciamento entre as pessoas. Essa medida de proteção à saúde e à vida favoreceu a implantação e/ou implementação da Telessaúde no Brasil que tem como premissa a melhoria da rede de serviços de saúde, sobretudo da Atenção Primária à Saúde (APS) a partir da teleconsultoria, telediagnóstico, telemonitoramento, telerregulação e teleducação. Aqui, o objetivo é apontar novos caminhos na atenção à saúde frente à infecção pelo novo coranavírus a partir da telessaúde. A Telessaúde no Paraná se estabeleceu com o advento da infecção pelo novo coronavírus e se efetivou a partir de projeto de extensão de prevenção e combate ao coronavirus que envolveu Sesa, Seti e IEES do estado. Desta forma, trata-se de relato de experiência de alunos bolsista desse projeto. A Telessáude já beneficiou mais de 1 milhão de pessoas no Brasil e mais de 8 mil pessoas no Paraná com as ações de teleconsultoria telediagnóstico, telemonitoramento e teleeducação no enfrentamento ao novo coronavirus. A Telessaúde tem o potencial para melhorar os serviços de saúde no pós-pandemia, pois tem se mostrado resolutiva, humanizada, garantindo baixo custo, acessibilidade e redução de filas nos serviços de saúde
Calcium-dependent release of adenosine and uridine nucleotides from A549 cells
Extracellular nucleotides play an important role in lung defense, but the release mechanism and relative abundance of different nucleotide species secreted by lung epithelia are not well defined. In this study, to minimize cell surface hydrolysis, we used a low-volume, flow-through chamber and examined adenosine and uridine nucleotide concentrations in perfusate aliquots of human lung A549 cells challenged by 50% hypotonic shock. Adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), and adenosine (Ado) were quantified in high-performance liquid chromatography (HPLC) analysis of fluorescent etheno derivatives, and uridine triphosphate (UTP) and uridine diphosphate (UDP) were measured using HPLC-coupled radioenzymatic assays. After the onset of hypotonic shock, ATP, ADP, UTP, and UDP in the perfusates increased markedly and peaked at approximately 2.5 min, followed by a gradual decay in the next 15–20 min; peak changes in Ado and AMP were relatively minor. The peak concentrations and fold increment (in parentheses) were: 34 ± 13 nM ATP (5.6), 11 ± 5 nM ADP (3.7), 3.3 ± 1.2 nM AMP (1.4), 23 ± 7 nM Ado (2.1), 21 nM UTP (>7), and 11 nM UDP (27). Nucleotide release was almost completely abolished from cells loaded with the calcium chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). Under isotonic conditions, elevation of intracellular calcium with the calcium ionophore ionomycin (5 μM, 3 min) also released nucleotides with kinetics and relative abundance as above, albeit less robust. ADP:ATP (1:3) and UDP:UTP (1:2) ratios in perfusates from stimulated cells were markedly higher than the cytosolic ratios of these species, suggesting that a nucleotide diphosphate (NDP)-rich compartment, e.g., the secretory pathway, contributed to nucleotide release. Laser confocal microscopy experiments illustrated increased FM1-43 uptake into the plasma membrane upon hypotonic shock or ionomycin treatment, consistent with enhanced vesicular exocytosis under these conditions. In summary, our results strongly suggest that calcium-dependent exocytosis is responsible, at least in most part, for adenosine and uridine nucleotide release from A549 cells
Hemolysis and ATP release from human and rat erythrocytes under conditions of hypoxia: a comparative study
Red blood cells are involved not only in transportation of oxygen and carbon dioxide but also in autoregulation of vascular tone by ATP release in hypoxic conditions. Molecular mechanisms of the ATP release from red blood cells in response to a decrease in partial oxygen pressure still remain to be elucidated. In this work we have studied effects of hypoxia on red blood cell hemolysis in humans and rats and compared the effects of inhibitors of ecto-ATPase and pannexin on the release of ATP and hemoglobin from rat erythrocytes. The 20-min hypoxia at 37°C increased hemolysis of red blood cells in humans and rats 1.5- and 2.5-fold, respectively. In rat erythrocytes a significant increase in hypoxia-induced extracellular ATP level was found only in the presence of ecto-ATPase inhibitor ARL 67156. In these conditions we observed a positive correlation (R2 = 0.5003) between the increase in free hemoglobin concentration and the ATP release. Neither carbenoxolon nor probenecid, the inhibitors of low-selectivity pannexin channels, altered the hypoxia-induced ATP release from rat erythrocytes. The obtained results indicate a key role of hemolysis in the ATP release from red blood cells
Deoxygenation affects composition of membrane-bound proteins in human erythrocytes
Background/Aims: ATP release from erythrocyte plays a key role in hypoxia-induced elevation of blood flow in systematic circulation. We have previously shown that hemolysis contributes to erythrocyte ATP release triggered by several stimuli, including hypoxia, but the molecular mechanisms of hypoxia-increased membrane fragility remain unknown. Methods: In this study, we compared the action of hypoxia on hemolysis, ATP release and the composition of membrane-bound proteins in human erythrocytes. Results: Twenty minutes incubation of human erythrocytes in the oxygen-free environment increased the content of extracellular hemoglobin by ∼1.5 fold. Paired measurements of hemoglobin and ATP content in the same samples, showed a positive correlation between hemolysis and ATP release. Comparative analysis of SDS-PAGE electrophoresis of erythrocyte ghosts obtained under control and deoxygenated conditions revealed a ∼2-fold elevation of the content of membrane-bound protein with Mr of ∼60 kDa. Conclusion: Deoxygenation of human erythrocytes affects composition of membrane-bound proteins. Additional experiments should be performed to identify the molecular origin of 60 kDa protein and its role in the attenuation of erythrocyte integrity and ATP release in hypoxic conditions
Cell to Cell Communication in Response to Mechanical Stress via Bilateral Release of Atp and Utp in Polarized Epithelia
Airway epithelia are positioned at the interface between the body and the environment, and generate complex signaling responses to inhaled toxins and other stresses. Luminal mechanical stimulation of airway epithelial cells produces a propagating wave of elevated intracellular Ca2+ that coordinates components of the integrated epithelial stress response. In polarized airway epithelia, this response has been attributed to IP3 permeation through gap junctions. Using a combination of approaches, including enzymes that destroy extracellular nucleotides, purinergic receptor desensitization, and airway cells deficient in purinoceptors, we demonstrated that Ca2+ waves induced by luminal mechanical stimulation in polarized airway epithelia were initiated by the release of the 5′ nucleotides, ATP and UTP, across both apical and basolateral membranes. The nucleotides released into the extracellular compartment interacted with purinoceptors at both membranes to trigger Ca2+ mobilization. Physiologically, apical membrane nucleotide-release coordinates airway mucociliary clearance responses (mucin and salt, water secretion, increased ciliary beat frequency), whereas basolateral release constitutes a paracrine mechanism by which mechanical stresses signal adjacent cells not only within the epithelium, but other cell types (nerves, inflammatory cells) in the submucosa. Nucleotide-release ipsilateral and contralateral to the surface stimulated constitutes a unique mechanism by which epithelia coordinate local and distant airway defense responses to mechanical stimuli
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