In major surgery, the implementation of multidisciplinary, multimodal and individualized strategies, collectively termed Patient Blood Management, aims to identify modifiable risks and optimise patients' own physiology with the ultimate goal of improving outcomes. Among the various strategies utilized in Patient Blood Management, timely detection and management of preoperative anaemia is most important, as it is in itself a risk factor for worse clinical outcome, but also one of the strongest predisposing factors for perioperative allogeneic blood transfusion, which in turn increases postoperative morbidity, mortality and costs. However, preoperative anaemia is still frequently ignored, with indiscriminate allogeneic blood transfusion used as a 'quick fix'. Consistent with reported evidence from other medical specialties, this imprudent practice continues to be endorsed by non-evidence based misconceptions, which constitute serious barriers for a wider implementation of preoperative haemoglobin optimisation. We have reviewed a number of these misconceptions, which we unanimously consider should be promptly abandoned by health care providers and replaced by evidence-based strategies such as detection, diagnosis and proper treatment of preoperative anaemia. We believe that this approach to preoperative anaemia management may be a viable, cost-effective strategy that is beneficial both for patients, with improved clinical outcomes, and for health systems, with more efficient use of finite health care resources.
An Asp-Arg-Tyr triad occurs in a majority of rhodopsin-like G protein-coupled receptors. The fully conserved Arg is critical for G protein activation, but the function of the flanking residues is not well understood. We expressed in COS-7 cells m1 muscarinic receptors that were mutated at Asp122 and Tyr124. Most mutations at either position strongly attenuated or prevented the expression of binding sites for the antagonist [3H]N-methylscopolamine. However, sites that were expressed displayed unaltered affinity for the antagonist. Receptor protein, visualized with a carboxyl-terminally directed antibody, was reduced but never completely abolished. The effects of these mutations were partially reversed by the deletion of 129 amino acids from the third intracellular loop of the receptor. In several cases, comparison of immunocytochemistry with binding measurements suggested the presence of substantial amounts of inactive, presumably misfolded, receptor protein. Some of the variants that bound [3H]N-methylscopolamine underwent small changes in their affinities for acetylcholine. All retained nearly normal abilities to mediate an acetylcholine-induced phosphoinositide response. We propose that Asp122 and Tyr124 make intramolecular contacts whose integrity is important for efficient receptor folding but that they do not participate directly in signaling. The role of these residues is completely distinct from that of Arg123, whose mutation abolishes signaling without diminishing receptor expression.
Background: Major role of oxidative stress in the pathogenesis of neurodegenerative diseases have been suggested, being mitochondria one of the main sources of ROS. Aim: In the present work, we have studied the antioxidant effect of fingolimod phosphate (FP) on neuronal mitochondrial function and morphology using a model of mitochondrial oxidative damage induced by menadione (Vitk3). Methods: SN4741 neuronal cells were grown (70-80% confluence) and used as control (nontreated cells) or treated cells with Vitk3 15 µM alone or in presence of FP 50 nM during 4 hours. Mitochondrial membrane potential (MMP), cytochrome c oxidase (COX) activity, mitochondrial oxygen consumption rate (OCR), mitochondrial distribution (MTG) and morphology (EM) were analysed. Statistical differences were determined using one-way ANOVA. Results: Vitk3 incubation produces a dramatical decrease in MMP compared to control (43.7 %); this can be almost totally reverted by the co-incubation of Vitk3 in presence of FP (p<0.05). A 20.7 % decrease in COX activity has been found after Vitk3 incubation, again this effect was counteracted when Vitk3 and FP are combined, restoring COX activity to control levels (p<0.05). Vitk3 incubation triggers initially an increase in OCR, decreasing dramatically (61%) after 4 hours. In experiments co-incubating Vitk3 in presence of FP, the OCR decrease found was reduced to only 17% (p<0.05). In experiments with MitoTracker™ Green, we found a change in the network pattern distribution after Vitk3 administration that partially disappears when co-incubated in presence of FP. Almost all the mitochondria treated with Vitk3 show ultrastructural alterations at the electron microscopy level while normal mitochondria can be found when Vitk3 and FP are combined. Conclusion: FP protects against the mitochondrial damage induced by Vitk3, as seen by the results obtained in mitochondrial functional markers, distribution and morphology.
Insulin-like growth factor-II (IGF-II) is a naturally occurring peptide that exerts known pleiotropic effects ranging from metabolic modulation to cellular development, growth and survival. IGF-II triggers its actions by binding to and activating IGF (IGF-I and IGF-II) receptors. In this study, we assessed the neuroprotective effect of IGF-II on corticosterone-induced oxidative damage in adult cortical neuronal cultures and the role of IGF-II receptors in this effect. We provide evidence that treatment with IGF-II alleviates the glucocorticoid-induced toxicity to neuronal cultures, and this neuroprotective effect occurred due to a decrease in reactive oxygen species (ROS) production and a return of the antioxidant status to normal levels. IGF-II acts via not only the regulation of synthesis and/or activity of antioxidant enzymes, especially manganese superoxide dismutase, but also the restoration of mitochondrial cytochrome c oxidase activity and mitochondrial membrane potential. Although the antioxidant effect of IGF-I receptor activation has been widely reported, the involvement of the IGF-II receptor in these processes has not been clearly defined. The present report is the first evidence describing the involvement of IGF-II receptors in redox homeostasis. IGF-II may therefore contribute to the mechanisms of neuroprotection by acting as an antioxidant, reducing the neurodegeneration induced by oxidative insults. These results open the field to new pharmacological approaches to the treatment of diseases involving imbalanced redox homeostasis. In this study, we demonstrated that the antioxidant effect of IGF-II is at least partially mediated by IGF-II receptors.
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