| 11. |
|
|
| 12. |
- Basu, Samar, et al.
(författare)
-
Development of a novel biomarker of free radical damage in reperfusion injury after cardiac arrest
- 2000
-
Ingår i: FEBS Letters. - 0014-5793 .- 1873-3468. ; 470:1, s. 1-6
-
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
|
|
| 13. |
|
|
| 14. |
- Basu, Samar, et al.
(författare)
-
Effects of melagatran, a novel direct thrombin inhibitor, during experimental septic shock
- 2000
-
Ingår i: Expert Opinion on Investigational Drugs. - : Informa Healthcare. - 1354-3784 .- 1744-7658. ; 9:5, s. 1129-1137
-
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.
|
|
| 15. |
- Basu, Samar, et al.
(författare)
-
Eicosanoids and Adipokines in Breast Cancer : From Molecular Mechanisms to Clinical Considerations
- 2013
-
Ingår i: Antioxidants and Redox Signaling. - : Mary Ann Liebert Inc. - 1523-0864 .- 1557-7716. ; 18:3, s. 323-360
-
Forskningsöversikt (refereegranskat)abstract
- Chronic inflammation is one of the foremost risk factors for different types of malignancies, including breast cancer. Additional risk factors of this pathology in postmenopausal women are weight gain, obesity, estrogen secretion, and an imbalance in the production of adipokines, such as leptin and adiponectin. Various signaling products of transcription factor, nuclear factor-kappaB, in particular inflammatory eicosanoids, reactive oxygen species (ROS), and cytokines, are thought to be involved in chronic inflammation-induced cancer. Together, these key components have an influence on inflammatory reactions in malignant tissue damage when their levels are deregulated endogenously. Prostaglandins (PGs) are well recognized in inflammation and cancer, and they are solely biosynthesized through cyclooxygenases (COXs) from arachidonic acid. Concurrently, ROS give rise to bioactive isoprostanes from arachidonic acid precursors that are also involved in acute and chronic inflammation, but their specific characteristics in breast cancer are less demonstrated. Higher aromatase activity, a cytochrome P-450 enzyme, is intimately connected to tumor growth in the breast through estrogen synthesis, and is interrelated to COXs that catalyze the formation of both inflammatory and anti-inflammatory PGs such as PGE(2), PGF(2 alpha), PGD(2), and PGJ(2) synchronously under the influence of specific mediators and downstream enzymes. Some of the latter compounds upsurge the intracellular cyclic adenosine monophosphate concentration and appear to be associated with estrogen synthesis. This review discusses the role of COX- and ROS-catalyzed eicosanoids and adipokines in breast cancer, and therefore ranges from their molecular mechanisms to clinical aspects to understand the impact of inflammation.
|
|
| 16. |
- Basu, Samar, et al.
(författare)
-
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
-
Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 37:3, s. 251-256
-
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.
|
|
| 17. |
|
|
| 18. |
- Basu, Samar
(författare)
-
F2-isoprostane induced prostaglandin formation in the rabbit
- 2006
-
Ingår i: Free radical research. - : Informa Healthcare. - 1071-5762 .- 1029-2470. ; 40:3, s. 273-277
-
Tidskriftsartikel (refereegranskat)abstract
- F2-isoprostanes, non-enzymatic free radical mediated products of arachidonic acid, have shown to form during various oxidant stress status and have potent biological effects. This study investigates to what extent 8-iso-PGF2α (a major F2-isoprostane), a bioactive product of lipid peroxidation can modify endogenous prostaglandin F2α (PGF2α) formation since prostaglandins are inflammatory as well as potent vasoregulatory substances that modulate diverse important physiological functions, and also form during acute and chronic inflammation. An immediate appearance and disappearance of 8-iso-PGF2α was seen in both plasma and urine within a short interval after i.v. administration of 43 μg/kg of 8-iso-PGF2α to the rabbits. A successive but differential formation of PGF2α resulted in a rapid and pulsatile increase of plasma 15-keto-dihydro-PGF2α, a major metabolite of primary PGF2α. Later, this compound was excreted efficiently as intact compound into the urine during the 3 h of experiment. A 8-fold increase of PGF2α metabolite in plasma at 10 min and 12-fold increase in the urine at 30–60 after the i.v. administration of 8-iso-PGF2α was observed which continued throughout the 3 h of experiment. This observation suggests that pharmacologically administered or endogenously produced 8-iso-PGF2α during oxidant stress induces prostaglandin formation presumbly through the classical cyclooxygenase-catalysed arachidonic acid oxidation which might be inflammatory itself to the cells and exerts further vasoconstrictive effects.
|
|
| 19. |
- Basu, Samar
(författare)
-
F2-isoprostanes in human health and diseases : from molecular mechanisms to clinical implications
- 2008
-
Ingår i: Antioxidants and Redox Signaling. - : Mary Ann Liebert. - 1523-0864 .- 1557-7716. ; 10:8, s. 1405-1434
-
Forskningsöversikt (refereegranskat)abstract
- Oxidative stress is implicated as one of the major underlying mechanisms behind many acute and chronic diseases, and involved in normal aging. However, the measurement of free radicals or their end products is complicated. Thus, proof of association of free radicals in pathologic conditions has been absent. Isoprostanes are prostaglandin-like bioactive compounds that are biosynthesized in vivo independent of cyclooxygenases, principally through free-radical catalyzation of arachidonic acid. Isoprostanes are now considered to be reliable biomarkers of oxidative stress, as evidenced by an autonomous study organized recently by the National Institutes of Health (NIH) in the United States. A number of these compounds have potent biologic activities such as vasoconstrictive and certain inflammatory properties. Isoprostanes are involved in many human diseases. Additionally, elevated levels of F2-isoprostanes have been seen in normal human pregnancy and after intake of some fatty acids, but their physiologic assignments have not yet been distinctive. This evidence indicates that measurement of bioactive F2-isoprostanes in body fluids offers a unique noninvasive analytic utensil to study the role of free radicals in physiology, oxidative stress–related diseases, experimental acute or chronic inflammatory conditions, and also in the assessment of various antioxidants, radical scavengers, and drugs.
|
|
| 20. |
|
|
