998 resultados para ACTIVATED CATION CURRENT
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Objectives: The study aims to assess the feasibility and midterm outcome of trans-peritoneal laparoscopy for coeliac artery compression syndrome (CACS).Design: Retrospective chart review involving four European vascular surgery departments and two surgical teams.Materials and methods: charts for patients who underwent laparoscopy for symptomatic CACS between December 2003 and November 2009 were reviewed. Preoperative computed tomography (CT) angiography and postoperative duplex scan and/or CT angiography were performed.Results: Eleven consecutive patients (nine women) with a median age of 52 years (interquartile range: 42.5-59 years) underwent trans-peritoneal laparoscopy for CACS. All patients had a history of postprandial abdominal pain; weight loss exceeded 10% of the body mass in eight cases. Preoperative CT angiography revealed coeliac trunk stenosis >70% in all cases. One patient had additional aortitis and inferior mesenteric artery occlusion, while another patient presented with an occluded superior mesenteric artery. Two conversions occurred (one difficult dissection and one aorto-hepatic bypass needed for incomplete release of CACS). The median blood loss was 195 ml (range: 50-900 ml) and median operative time was 80 min (interquartile range: 65-162.5 years). Symptoms improved immediately in 10/11 patients (no residual stenosis) while one remained unchanged despite a residual stenosis treated by a percutaneous angioplasty. Symptoms reappeared in one patient due to coeliac axis occlusion. The mean follow-up period was 35 +/- 23 months (range: 12-78 months).Conclusion: Our study demonstrates that trans-peritoneal laparoscopy for treating median arcuate ligament syndrome is safe and feasible. Additional patients and a longer follow-up are needed for long-term assessment of this laparoscopic technique. (C) 2011 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.
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Treatment of colonic diverticular disease has evolved over the past years. Most episodes are simple and can be successfully treated with antibiotics alone. For complicated diverticulitis, a strong trend is developing towards less invasive therapies including interventional radiology and laparoscopic lavage in an effort to avoid the morbidity and discomfort of a diverting colostomy. Based on a better understanding of the natural history of the disease, the indication to prophylactic colectomy after a few episodes of simple diverticulitis has been seriously challenged. For those patients who need a colectomy, single port laparoscopy, NOTES and transanal specimen extraction are being proposed. However larger studies are needed to confirm the hypothetical advantages of these evolving techniques.
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BACKGROUND: Neuropsychological deficits (NPD) are common in patients with aneurysmal subarachnoid haemorrhage (aSAH). NPD are one of the major limiting factors for patients with an otherwise acceptable prognosis for sustained quality of life. There are only a few studies reporting outcome after aSAH, which used a standardized neuropsychological test battery as a primary or secondary outcome measure. Aim of this study was to determine the current practice of reporting NPD following aSAH in clinical studies. METHODS: A MEDLINE analysis was performed using the search term "subarachnoid haemorrhage outcome". The latest 1,000 articles were screened. We recorded study design, number of patients, and the presence of neuropsychological outcome report. Additionally, the time of testing after aSAH, the neuropsychological tests administered, as well as the percentage of patients with NPD were analyzed. RESULTS: A total of 324 publications between 2009 and 2012 were selected for further review. Of those, 21 studies (6.5%) reported neuropsychological outcome, in 2,001 of 346,666 patients (0.6%). The assessment of NPD differed broadly using both subjective and objective cognitive evaluation, and a large variety of tests were used. CONCLUSION: Neuropsychological outcome is underreported, and there is great variety in assessment in currently published clinical articles on aSAH. Prospective randomized trials treating aSAH may benefit from implementing more comprehensive and standardized neuropsychological outcome measures. This approach might identify otherwise unnoticed treatment effects in future interventional studies of aSAH patients.
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The PPARs (peroxisome-proliferator-activated receptors) alpha, beta/delta and gamma belong to the nuclear hormone receptor superfamily. While all three receptors are undetectable in adult mouse interfollicular epidermis, PPARbeta expression and activity is strongly re-activated by inflammatory stimuli during epidermal injury. The pro-inflammatory cytokine TNFalpha (tumour necrosis factor alpha) stimulates transcription of the PPARbeta gene via an activator protein-1 site in its promoter and it also triggers the production of PPARbeta ligands in keratinocytes. This increase of PPARbeta activity in these cells up-regulates the expression of integrin-linked kinase and 3-phosphoinositide-dependent kinase-1, which phosphorylates protein kinase B-alpha (Akt1). The resulting increase in Akt1 activity suppresses apoptosis and ensures the presence of a sufficient number of viable keratinocytes at the wound margin for re-epithelialization. Together, these observations reveal that PPARbeta takes on multiple roles and contributes favourably to the process of wound closure.
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Hepatitis C virus (HCV) infection induces the endogenous interferon (IFN) system in the liver in some but not all patients with chronic hepatitis C (CHC). Patients with a pre-activated IFN system are less likely to respond to the current standard therapy with pegylated IFN-alpha. Mitochondrial antiviral signaling protein (MAVS) is an important adaptor molecule in a signal transduction pathway that senses viral infections and transcriptionally activates IFN-beta. The HCV NS3-4A protease can cleave and thereby inactivate MAVS in vitro, and, therefore, might be crucial in determining the activation status of the IFN system in the liver of infected patients. We analyzed liver biopsies from 129 patients with CHC to investigate whether MAVS is cleaved in vivo and whether cleavage prevents the induction of the endogenous IFN system. Cleavage of MAVS was detected in 62 of the 129 samples (48%) and was more extensive in patients with a high HCV viral load. MAVS was cleaved by all HCV genotypes (GTs), but more efficiently by GTs 2 and 3 than by GTs 1 and 4. The IFN-induced Janus kinase (Jak)-signal transducer and activator of transcription protein (STAT) pathway was less frequently activated in patients with cleaved MAVS, and there was a significant inverse correlation between cleavage of MAVS and the expression level of the IFN-stimulated genes IFI44L, Viperin, IFI27, USP18, and STAT1. We conclude that the pre-activation status of the endogenous IFN system in the liver of patients with CHC is in part regulated by cleavage of MAVS.
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The cellular response to fasting and starvation in tissues such as heart, skeletal muscle, and liver requires peroxisome proliferator-activated receptor-alpha (PPARalpha)-dependent up-regulation of energy metabolism toward fatty acid oxidation (FAO). PPARalpha null (PPARalphaKO) mice develop hyperinsulinemic hypoglycemia in the fasting state, and we previously showed that PPARalpha expression is increased in islets at low glucose. On this basis, we hypothesized that enhanced PPARalpha expression and FAO, via depletion of lipid-signaling molecule(s) for insulin exocytosis, are also involved in the normal adaptive response of the islet to fasting. Fasted PPARalphaKO mice compared with wild-type mice had supranormal ip glucose tolerance due to increased plasma insulin levels. Isolated islets from the PPARalpha null mice had a 44% reduction in FAO, normal glucose use and oxidation, and enhanced glucose-induced insulin secretion. In normal rats, fasting for 24 h increased islet PPARalpha, carnitine palmitoyltransferase 1, and uncoupling protein-2 mRNA expression by 60%, 62%, and 82%, respectively. The data are consistent with the view that PPARalpha, via transcriptionally up-regulating islet FAO, can reduce insulin secretion, and that this mechanism is involved in the normal physiological response of the pancreatic islet to fasting such that hypoglycemia is avoided.
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Estrogen deprivation is associated with delayed healing, while Hormone Replacement Therapy (HRT) accelerates acute wound healing and protects against development of chronic wounds. Estrogen exerts its effects on healing via numerous cell types by signalling through the receptors ERα and ERβ, which bind to the Estrogen Responsive Element (ERE) and initiate gene transcription. The ERE-luciferase transgenic mouse model has been influential in assessing real-time in vivo estrogen receptor activation across a range of tissues and pathologies. Using this model we demonstrate novel temporally regulated peri-wound activation of estrogen signalling in female mice. Using histological methods we reveal that this signal is specifically localised to keratinocytes of the neoepidermis and wound margin dermal cells. Moreover using pharmacological agonists we reveal that ERβ induces ERE-mediated signal in both epidermal and dermal cells while ERα induces ERE-mediated signal in dermal cells alone. Collectively these novel data demonstrate rapid and regional activation of estrogen signalling in wounded skin. A more complete understanding of local hormonal signalling during repair is essential for the focussed development of new therapies for wound healing.
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This article extends existing discussion in literature on probabilistic inference and decision making with respect to continuous hypotheses that are prevalent in forensic toxicology. As a main aim, this research investigates the properties of a widely followed approach for quantifying the level of toxic substances in blood samples, and to compare this procedure with a Bayesian probabilistic approach. As an example, attention is confined to the presence of toxic substances, such as THC, in blood from car drivers. In this context, the interpretation of results from laboratory analyses needs to take into account legal requirements for establishing the 'presence' of target substances in blood. In a first part, the performance of the proposed Bayesian model for the estimation of an unknown parameter (here, the amount of a toxic substance) is illustrated and compared with the currently used method. The model is then used in a second part to approach-in a rational way-the decision component of the problem, that is judicial questions of the kind 'Is the quantity of THC measured in the blood over the legal threshold of 1.5 μg/l?'. This is pointed out through a practical example.
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Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors that can be activated by fatty acids and peroxisome proliferators. The PPAR alpha subtype mediates the pleiotropic effects of these activators in liver and regulates several target genes involved in fatty acid catabolism. In primary hepatocytes cultured in vitro, the PPAR alpha gene is regulated at the transcriptional level by glucocorticoids. We investigated if this hormonal regulation also occurs in the whole animal in physiological situations leading to increased plasma corticosterone levels in rats. We show here that an immobilization stress is a potent and rapid stimulator of PPAR alpha expression in liver but not in hippocampus. The injection of the synthetic glucocorticoid dexamethasone into adult rats produces a similar increase in PPAR alpha expression in liver, whereas the administration of the antiglucocorticoid RU 486 inhibits the stress-dependent stimulation. We conclude that glucocorticoids are major mediators of the stress response. Consistent with this hormonal regulation, hepatic PPAR alpha mRNA and protein levels follow a diurnal rhythm, which parallels that of circulating corticosterone. To test the effects of variations in PPAR alpha expression on PPAR alpha target gene activity, high glucocorticoid-dependent PPAR alpha expression was mimicked in cultured primary hepatocytes. Under these conditions, hormonal stimulation of receptor expression synergizes with receptor activation by WY-14,643 to induce the expression of the PPAR alpha target gene acyl-CoA oxidase. Together, these results show that regulation of the PPAR alpha expression levels efficiently modulates PPAR activator signaling and thus may affect downstream metabolic pathways involved in lipid homeostasis.
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The malic enzyme (ME) gene is a target for both thyroid hormone receptors and peroxisome proliferator-activated receptors (PPAR). Within the ME promoter, two direct repeat (DR)-1-like elements, MEp and MEd, have been identified as putative PPAR response elements (PPRE). We demonstrate that only MEp and not MEd is able to bind PPAR/retinoid X receptor (RXR) heterodimers and mediate peroxisome proliferator signaling. Taking advantage of the close sequence resemblance of MEp and MEd, we have identified crucial determinants of a PPRE. Using reciprocal mutation analyses of these two elements, we show the preference for adenine as the spacing nucleotide between the two half-sites of the PPRE and demonstrate the importance of the two first bases flanking the core DR1 in 5'. This latter feature of the PPRE lead us to consider the polarity of the PPAR/RXR heterodimer bound to its cognate element. We demonstrate that, in contrast to the polarity of RXR/TR and RXR/RAR bound to DR4 and DR5 elements respectively, PPAR binds to the 5' extended half-site of the response element, while RXR occupies the 3' half-site. Consistent with this polarity is our finding that formation and binding of the PPAR/RXR heterodimer requires an intact hinge T region in RXR while its integrity is not required for binding of the RXR/TR heterodimer to a DR4.
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Cardiovascular risk assessment might be improved with the addition of emerging, new tests derived from atherosclerosis imaging, laboratory tests or functional tests. This article reviews relative risk, odds ratios, receiver-operating curves, posttest risk calculations based on likelihood ratios, the net reclassification improvement and integrated discrimination. This serves to determine whether a new test has an added clinical value on top of conventional risk testing and how this can be verified statistically. Two clinically meaningful examples serve to illustrate novel approaches. This work serves as a review and basic work for the development of new guidelines on cardiovascular risk prediction, taking into account emerging tests, to be proposed by members of the 'Taskforce on Vascular Risk Prediction' under the auspices of the Working Group 'Swiss Atherosclerosis' of the Swiss Society of Cardiology in the future.
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The major problems associated with the use of corticosteroids for the treatment of ocular diseases are their poor intraocular penetration to the posterior segment when administered locally and their secondary side effects when given systemically. To circumvent these problems more efficient methods and techniques of local delivery are being developed. The purposes of this study were: (1) to investigate the pharmacokinetics of intraocular penetration of hemisuccinate methyl prednisolone (HMP) after its delivery using the transscleral Coulomb controlled iontophoresis (CCI) system applied to the eye or after intravenous (i.v.) injection in the rabbit, (2) to test the safety of the CCI system for the treated eyes and (3) to compare the pharmacokinetic profiles of HMP intraocular distribution after CCI delivery to i.v. injection. For each parameter evaluated, six rabbit eyes were used. For the CCI system, two concentrations of HMP (62.5 and 150mg ml(-1)), various intensities of current and duration of treatment were analyzed. In rabbits serving as controls the HMP was infused in the CCI device but without applied electric current. For the i.v. delivery, HMP at 10mg kg(-1)as a 62.5mg ml(-1)solution was used. The rabbits were observed clinically for evidence of ocular toxicity. At various time points after the administration of drug, rabbits were killed and intraocular fluids and tissues were sampled for methylprednisolone (MP) concentrations by high pressure liquid chromatography (HPLC). Histology examinations were performed on six eyes of each group. Among groups that received CCI, the concentrations of MP increased in all ocular tissues and fluids in relation to the intensities of current used (0.4, 1.0 and 2.0mA/0.5cm(2)) and its duration (4 and 10min). Sustained and highest levels of MP were achieved in the choroid and the retina of rabbit eyes treated with the highest current and 10min duration of CCI. No clinical toxicity or histological lesions were observed following CCI. Negligible amounts of MP were found in ocular tissues in the CCI control group without application of current. Compared to i.v. administration, CCI achieved higher and more sustained tissue concentrations with negligible systemic absorption. These data demonstrate that high levels of MP can be safely achieved in intraocular tissues and fluids of the rabbit eye, using CCI. With this system, intraocular tissues levels of MP are higher than those achieved after i.v. injection. Furthermore, if needed, the drug levels achieved with CCI can be modulated as a function of current intensity and duration of treatment. CCI could therefore be used as an alternative method for the delivery of high levels of MP to the intraocular tissues of both the anterior and posterior segments.
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The peroxisome proliferator-activated receptors (PPAR) and thyroid hormone receptors (TR) are members of the nuclear receptor superfamily, which regulate lipid metabolism and tissue differentiation. In order to bind to DNA and activate transcription, PPAR requires the formation of heterodimers with the retinoid X receptor (RXR). In addition to activating transcription through its own response elements, PPAR is able to selectively down-regulate the transcriptional activity of TR, but not vitamin D receptor. The molecular basis of this functional interaction has not been fully elucidated. By means of site-directed mutagenesis of hPPAR alpha we mapped its inhibitory action on TR to a leucine zipper-like motif in the ligand binding domain of PPAR, which is highly conserved among all subtypes of this receptor and mediates heterodimerization with RXR. Replacement of a single leucine by arginine at position 433 of hPPAR alpha (L433R) abolished heterodimerization of PPAR with RXR and consequently its trans-activating capacity. However, a similar mutation of a leucine residue to arginine at position 422 showed no alteration of heterodimerization, DNA binding, or transcriptional activation. The dimerization deficient mutant L433R was no longer able to inhibit TR action, demonstrating that the selective inhibitory effect of PPAR results from the competition for RXR as well as possibly for other TR-auxiliary proteins. In contrast, abolition of DNA binding by a mutation in the P-box of PPAR (C122S) did not eliminate the inhibition of TR trans-activation, indicating that competition for DNA binding is not involved. Additionally, no evidence for the formation of PPAR:TR heterodimers was found in co-immunoprecipitation experiments. In summary, we have demonstrated that PPAR selectively inhibits the transcriptional activity of TRs by competition for RXR and possibly non-RXR TR-auxiliary proteins. In contrast, this functional interaction is independent of the formation of PPAR:TR heterodimers or competition for DNA binding.