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- Basu, Samar, et al.
(författare)
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Association between oxidative stress and bone mineral density
- 2001
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 288:1, s. 275-9
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Tidskriftsartikel (refereegranskat)abstract
- Free radicals have been shown to be involved in bone resorption in vitro and in rodents. We studied the effect of oxidative stress on bone mineral density (BMD) in 48 women and 53 men from a population-based study. The levels of 8-iso-PGF(2alpha) (a major F(2)-isoprostane and a biomarker of oxidative stress) and a control, 15-keto-dihydro-PGF(2alpha) (a biomarker of inflammatory response), were measured in urinary samples and their association with BMD and quantitative ultrasound (QUS) measurements were examined. In multivariate linear regression analyses, 8-iso-PGF(2alpha) levels were negatively associated with both BMD and QUS. In contrast, no association was found for 15-keto-dihydro-PGF(2alpha). Our findings establish a biochemical link between increased oxidative stress and reduced bone density and provide a rational for further studies investigating the role of pro- and antioxidants in osteoporosis. Copyright 2001 Academic Press.
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| 2. |
- Basu, Samar, et al.
(författare)
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Biomarkers of free radical injury during spinal cord ischemia
- 2001
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Ingår i: FEBS Letters. - 0014-5793 .- 1873-3468. ; 508:1, s. 36-38
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Tidskriftsartikel (refereegranskat)abstract
- Plasma and urinary levels of 8-iso-PGF(2alpha) and 15-keto-dihydro-PGF(2alpha) were analysed at baseline and during the ischemia-reperfusion period in experimental spinal cord ischemia. A significant and immediate increase of 8-iso-PGF(2alpha) in plasma at the start and up to 60 min, and in the urine at 90-150 min following ischemia indicate an association of oxidative injury. The inflammatory response indicator 15-keto-dihydro-PGF(2alpha) in plasma increased significantly at the start and up to 60 min after ischemia. No such increase was seen in animals with no spinal cord ischemia. Thus, free radical mediated and cyclooxygenase catalysed products of arachidonic acid are increased during spinal cord ischemia as a consequence of oxidative injury and inflammation.
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| 6. |
- Basu, Samar, et al.
(författare)
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Development of a novel biomarker of free radical damage in reperfusion injury after cardiac arrest
- 2000
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Ingår i: FEBS Letters. - 0014-5793 .- 1873-3468. ; 470:1, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- In a porcine model of cardiopulmonary resuscitation (CPR), we investigated changes in the plasma levels of 8-iso-PGF(2alpha), a marker for oxidative injury, and 15-keto-dihydro-PGF(2alpha), an inflammatory response indicator during the post-resuscitation period after cardiac arrest. Twelve piglets were subjected to either 2 or 5 min (VF2 and VF5 group) of ventricular fibrillation (VF) followed by 5 min of closed-chest CPR. Six piglets without cardiac arrest were used as controls. In VF5 group, 8-iso-PGF(2alpha) in the jugular bulb plasma (draining the brain) increased four-fold. Jugular bulb 8-iso-PGF(2alpha) in the control group remained unchanged. The 15-keto-dihydro-PGF(2alpha) also increased four-fold in the VF5 group. Thus, 8-iso-PGF(2alpha) and 15-keto-dihydro-PGF(2alpha) measurements in jugular bulb plasma may be used as biomarkers for quantification of free radical catalyzed oxidative brain injury and inflammatory response in reperfusion injury
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| 7. |
- Basu, Samar, et al.
(författare)
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Effects of melagatran, a novel direct thrombin inhibitor, during experimental septic shock
- 2000
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Ingår i: Expert Opinion on Investigational Drugs. - : Informa Healthcare. - 1354-3784 .- 1744-7658. ; 9:5, s. 1129-1137
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Tidskriftsartikel (refereegranskat)abstract
- Sepsis and endotoxaemia initiate the generation of thrombin, which is responsible for the conversion of fibrinogen to fibrin, platelet aggregation and acts as an inflammatory mediator affecting numerous types of cells, including myocardial, smooth muscle and endothelial cells. Human Gram-negative septic shock, frequently seen in intensive care units, is a condition with high mortality. This condition can be replicated in the endotoxaemic pig. As many of the toxic effects of sepsis are due to thrombin generation, it was of interest to study, using this porcine experimental septic shock model, whether inhibition of thrombin could alleviate the effects of endotoxaemia. For this purpose melagatran, a direct synthetic thrombin inhibitor with a molecular weight of 429 Da, was employed. Melagatran does not significantly interact with any other enzymes in the coagulation cascade or fibrinolytic enzymes aside from thrombin. Furthermore, melagatran does not require endogenous co-factors such as antithrombin or heparin co-Factor II for its antithrombin effect, which is important, as these inhibitors are often consumed in septic patients. We have shown that melagatran exerts a beneficial effect on renal function, as evaluated by plasma creatinine and urinary output, during experimental septic shock. These effects were most pronounced during the later phase of the experimental period, after the infusion of melagatran had been discontinued. Prevention of intrarenal coagulation may be attributable to this finding. In addition, melagatran had beneficial effects on systemic haemodynamics (left ventricular stroke work index, pulmonary capillary wedge pressure and systemic vascular resistance index) in endotoxaemic pigs. This result may be explained by the ability of melagatran to inhibit thrombin, thereby counteracting thrombin's cellular effects. Thus, it can be seen, using this experimental model of septic shock, that melagatran may help to alleviate some of the damaging effects of endotoxaemia, although more research is required to test this further.
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| 8. |
- Basu, Samar, et al.
(författare)
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Evidence for Time-dependent Maximum Increase ofFree Radical Damage and Eicosanoid Formation in theBrain as Related to Duration of Cardiac Arrest andCardio-pulmonary Resuscitation
- 2003
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 37:3, s. 251-256
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Tidskriftsartikel (refereegranskat)abstract
- Recovery of neurological function in patients following cardiac arrest and cardiopulmonary resuscitation (CPR) is a complex event. Free radical induced oxidative stress is supposed to be involved in this process. We studied levels of 8-iso-PGF2alpha (indicating oxidative injury) and 15-keto-dihydro-PGF2alpha (indicating inflammatory response) in venous plasma obtained from the jugular bulb in a porcine model of experimental cardiopulmonary resuscitation (CPR) where 2, 5, 8, 10 or 12 min of ventricular fibrillation (VF) was followed by 5 or 8 min of closed-chest CPR. A significant increase of 8-iso-PGF2alpha was observed immediately following restoration of spontaneous circulation in all experiments of various duration of VF and CPR. No such increase was seen in a control group. When compared between the groups there was a duration-dependent maximum increase of 8-iso-PGF2alpha which was greatest in animals subjected to the longest period (VF12 min + CPR8 min) of no or low blood flow. In contrast, the greatest increase of 15-keto-dihydro-PGF2alpha was observed in the 13 min group (VF8 min + CPR5 min). Thus, a time-dependent cerebral oxidative injury occurs in conjunction which cardiac arrest and CPR.
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| 10. |
- Basu, Samar, et al.
(författare)
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Lipid peroxidation induced by an early inflammatory response in endotoxaemia
- 2000
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 44:1, s. 17-23
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Endotoxaemic challenge promptly causes lipid peroxidation. Porcine endotoxaemia can be used to replicate severe human septic shock. This model was used to evaluate non-enzymatic [8-Iso-prostaglandin F2alpha (8-Iso-PGF2alpha)] and enzymatic [15-keto-13,14-dihydro-prostaglandin F2alpha (15-K-DH-PGF2alpha)] lipid peroxidation, respectively, in relation to survival. The aim of this study was to correlate, if possible, pathophysiologic events during endotoxaemia to the levels of these arachidonic acid metabolites. METHODS: Nineteen pigs were anaesthetised, monitored (circulatory and respiratory variables in relation to lipid peroxidation) and given a continuous 6 h E. coli endotoxin (10 microg x kg(-1) x h(-1)) infusion. All animals were mechanically ventilated at constant tidal volumes and the inspired oxygen fraction was kept constant during the experimental period. RESULTS: This endotoxin infusion caused expressed derangements in all pigs and death in 9 of them. The levels of 8-Iso-PGF2alpha, indicating oxidative injury, were different in time course, magnitude and fashion between survivors and non-survivors. The levels of 15-K-DH-PGF2alpha, indicating inflammatory response, showed a similar pattern. At 1 h the CO2 partial pressure in arterial blood was significantly higher in non-surviving pigs and correlated (r: 0.7; P<0.05) to the levels of 15-K-DH-PGF2alpha. Prostaglandin F2alpha is mainly metabolised in the lung. The lung weights were significantly (P<0.05) higher in non-surviving than in surviving animals. Both free radical and cyclooxygenase catalysed oxidative modification occurs during endotoxaemia. CONCLUSION: Increased metabolism and inflammation, as evaluated by 15-K-DH-PGF2alpha, in the group of non-survivors may mediate the increase in arterial CO2. Thus, increased lipid peroxidation seems to be associated with endotoxaemic organ dysfunction and increased mortality.
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