| 1. |
- Barklin, Anne, et al.
(författare)
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Alteration of Neuropeptides in the Lung Tissue Correlates Brain Death-Induced Neurogenic Edema
- 2009
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Ingår i: JOURNAL OF HEART AND LUNG TRANSPLANTATION. - : Elsevier BV. - 1053-2498 .- 1557-3117. ; 28:7, s. 725-732
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Tidskriftsartikel (refereegranskat)abstract
- Background: increased intracranial pressure induces neurogenic pulmonary edema (NPE), potentially explaining why only lungs from less than 20% of brain dead organ donors can be used for transplantation. This study investigated the underlying mechanisms of NPE, focusing on neuropeptides, which potently induce vasoconstriction, vasodilatation, and neurogenic inflammation. Methods: Brain death was induced in 10 pigs by increasing the intracranial pressure. Eight additional pigs served as controls. Neuropeptide Y (NPY), calcitonin gene-related peptide (CGRP), and substance P were analyzed in plasma, bronchoalveolar lavage (BAL) fluid, and homogenized lung tissue 6 hours after brain death. Pulmonary oxygen exchange was estimated using partial pressure of arterial oxygen (Pao(2))/fraction of inspired oxygen (FIO2), and pulmonary edema by wet/dry weight ratio. Results: Brain death induced a decrease in PaO2/FIO2 (P less than 0.001) and increased the wet/dry weight of both apical (p = 0.01) and basal lobes (p = 0.03). NPY and CGRP concentrations were higher in the BAL fluid of brain-dead animals compared with controls (p = 0.02 and p = 0.02) and were positively correlated with the wet/dry weight ratio. NPY content in lung tissue was lower in brain-dead animals compared with controls (p = 0.04) and was negatively correlated with the wet/dry weight ratio. There were no differences in substance P concentrations between the groups. Conclusion: NPY was released from the lung tissue of brain-dead pigs, and its concentration was related to the extent of pulmonary edema. NPY may be one of several crucial mediators of neurogenic pulmonary edema, raising the possibility of treatment with NPY-antagonists to increase the number of available lung donors.
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| 2. |
- Buhl, Mads, et al.
(författare)
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Circulating Free Fatty Acids do not Contribute to the Acute Systemic Inflammatory Response. An Experimental Study in Porcine Endotoxaemia
- 2009
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Ingår i: Basic & Clinical Pharmacology & Toxicology. - : Wiley. - 1742-7843 .- 1742-7835. ; 105:5, s. 319-326
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Tidskriftsartikel (refereegranskat)abstract
- Intensive insulin therapy, aiming for strict normoglycaemia, is associated with increased survival in critically ill patients. Insulin therapy concomitantly reduces plasma-free fatty acids. Recent studies indicate that free fatty acids mediate inflammation. In addition to plasma glucose and free fatty acid-lowering effects, insulin also has anti-inflammatory properties. This study was designed to study the pro-inflammatory effects of two free fatty acid concentrations during acute endotoxaemia and controlled comparable levels of plasma glucose and insulin. Twenty pigs were anaesthetized and mechanically ventilated. Pigs were randomized to two different, constant Intralipid (R) infusion rates, throughout observation. All pigs were administered continuous intravenous infusion of endotoxin and subjected to controlled levels of p-glucose (4.5 mmol/l) and insulin by use of a hyperinsulinaemic euglycaemic clamp. Changes in circulating tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, leucocytes, insulin, glucose, free fatty acids, triglycerides, albumin, blood gases, temperature, and, haemodynamic function were monitored. Immediately following killing, biopsies were taken from heart and kidney. Biopsies were analysed for protein content of TNF-alpha, IL-6, IL-8 and IL-10. Sustained elevated and significantly different plasma levels of free fatty acids were demonstrated between groups (mean free fatty acid concentrations, 1.62 mM versus 0.58 mM, p < 0.0002). Endotoxaemia induced a steep increase in plasma TNF-alpha, IL-6 and leucocytes, however, without differences between the low- and high-free fatty acid groups. Cytokine content in heart and kidney tissue was not modified by free fatty acids. Compared with the response obtained at lower free fatty acid levels, high free fatty acid levels did not exacerbate the inflammatory response to acute endotoxaemia. Our results do not support the role of free fatty acids as a significant pro-inflammatory mediator.
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| 3. |
- Christensen, Steffen, et al.
(författare)
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Preadmission beta-blocker use and 30-day mortality among patients in intensive care : a cohort study
- 2011
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Ingår i: Critical Care. - : Springer Science and Business Media LLC. - 1364-8535 .- 1466-609X. ; 15:2, s. R87-
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Beta-blockers have cardioprotective, metabolic and immunomodulating effects that may be beneficial to patients in intensive care. We examined the association between preadmission beta-blocker use and 30-day mortality following intensive care. Methods: We identified 8,087 patients over age 45 admitted to one of three multidisciplinary intensive care units (ICUs) between 1999 and 2005. Data on the use of beta-blockers and medications, diagnosis, comorbidities, surgery, markers of socioeconomic status, laboratory tests upon ICU admission, and complete follow-up for mortality were obtained from medical databases. We computed probability of death within 30 days following ICU admission for beta-blocker users and non-users, and the odds ratio (OR) of death as a measure of relative risk using conditional logistic regression and also did a propensity score-matched analysis. Results: Inclusion of all 8,087 ICU patients in a logistic regression analysis yielded an adjusted OR of 0.82 (95% confidence interval (CI): 0.71 to 0.94) for beta-blocker users compared with non-users. In the propensity score-matched analysis we matched all 1,556 beta-blocker users (19.2% of the entire cohort) with 1,556 non-users; the 30-day mortality was 25.7% among beta-blocker users and 31.4% among non-users (OR 0.74 (95% CI: 0.63 to 0.87)]. The OR was 0.69 (95% CI: 0.54 to 0.88) for surgical ICU patients and 0.71 (95% CI: 0.51 to 0.98) for medical ICU patients. The OR was 0.99 (95% CI: 0.67 to 1.47) among users of non-selective beta-blockers, and 0.70 (95% CI: 0.58 to 0.83) among users of cardioselective beta-blockers. Conclusions: Preadmission beta-blocker use is associated with reduced mortality following ICU admission.
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| 4. |
- Overgaard-Steensen, Christian, et al.
(författare)
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The frequently used intraperitoneal hyponatraemia model induces hypovolaemic hyponatraemia with possible model-dependent brain sodium loss
- 2016
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Ingår i: Experimental Physiology. - 0958-0670 .- 1469-445X. ; 101:7, s. 932-945
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Tidskriftsartikel (refereegranskat)abstract
- Hyponatraemia is common clinically, and if it develops rapidly, brain oedema evolves, and severe morbidity and even death may occur. Experimentally, acute hyponatraemia is most frequently studied in small animal models, in which the hyponatraemia is produced by intraperitoneal instillation of hypotonic fluids (I.P. model). This hyponatraemia model is described as 'dilutional' or 'syndrome of inappropriate ADH (SIADH)', but seminal studies contradict this interpretation. To confront this issue, we developed an I.P. model in a large animal (the pig) and studied water and electrolyte responses in brain, muscle, plasma and urine. We hypothesized that hyponatraemia was induced by simple water dilution, with no change in organ sodium content. Moderate hypotonic hyponatraemia was induced by a single I.V. dose of desmopressin and intraperitoneal instillation of 2.5% glucose. All animals were anaesthetized and intensively monitored. In vivo brain and muscle water was determined by magnetic resonance imaging and related to the plasma sodium concentration. Muscle water content increased less than expected as a result of pure dilution, and muscle sodium content decreased significantly (by 28%). Sodium was redistributed to the peritoneal fluid, resulting in a significantly reduced plasma volume. This shows that the I.P. model induces hypovolaemic hyponatraemia and not dilutional/SIADH hyponatraemia. Brain oedema evolved, but brain sodium content decreased significantly (by 21%). To conclude, the I.P. model induces hypovolaemic hyponatraemia attributable to sodium redistribution and not water dilution. The large reduction in brain sodium is probably attributable to the specific mechanism that causes the hyponatraemia. This is not accounted for in the current understanding of the brain response to acute hyponatraemia.
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