N-acetyl Cysteine (n-acetyl + cysteine)

Distribution by Scientific Domains

Selected Abstracts

Iron-induced oxidative stress up-regulates calreticulin levels in intestinal epithelial (Caco-2) cells

Marco T. Nez
Abstract Calreticulin, a molecular chaperone involved in the folding of endoplasmic reticulum synthesized proteins, is also a shock protein induced by heat, food deprivation, and chemical stress. Mobilferrin, a cytosolic isoform of calreticulin, has been proposed to be an iron carrier for iron recently incoming into intestinal cells. To test the hypothesis that iron could affect calreticulin expression, we investigated the possible associations of calreticulin with iron metabolism. To that end, using Caco-2 cells as a model of intestinal epithelium, the mass and mRNA levels of calreticulin were evaluated as a function of the iron concentration in the culture media. Increasing the iron content in the culture from 1 to 20 ,M produced an increase in calreticulin mRNA and a two-fold increase in calreticulin. Increasing iron also induced oxidative damage to proteins, as assessed by the formation of 4-hydroxy-2-nonenal adducts. Co-culture of cells with the antioxidants quercetin, dimethyltiourea and N-acetyl cysteine abolished both the iron-induced oxidative damage and the iron-induced increase in calreticulin. We postulate that the iron-induced expression of calreticulin is part of the cellular response to oxidative stress generated by iron. J. Cell. Biochem. 82: 660,665, 2001. 2001 Wiley-Liss, Inc. [source]

Sphingolipids in rat model of transient focal cerebral ischemia: implication for stroke injury

M. Khan
Lipids are essential for signal transduction in response to trauma leading to neurodegeneration. Ceramide is an important mediator of apoptosis and cell proliferation. We studied the involvement of ceramide/sphingomyelin pathway in rat brain (stroke model) after 45 min ischemia followed by 24-h reperfusion. Ischemia was performed through occlusion of right middle cerebral artery (MCA). The level of ceramide was found increased (70,100% in ischemic side of brain v/s contralateral side of brain). Sphingomyelin levels were also decreased by 20,25% in ischemic brain v/s contralateral side of brain. Increase in ceramide and decrease in sphingomyelin were in good agreement with observed apoptotic cell loss (TUNEL assay) and decrease in the level of cardiolipin (a mitochondrian specific phospholipids) in affected ischemic brain. N-acetyl cysteine (NAC), a therapeutic agent recognized as potent antioxidant provided protective effect. Pretreatment with NAC before ischemia reduced the infarct volume size, suppressed apoptosis, restored cardiolipin level and decreased the levels of free fatty acids. However, NAC did not normalize the ceramide level. These interesting observations raise a question about the role of ceramide and its relationship with apoptosis and oxidative stress in rat brain ischemia. Acknowledgements:, Supported by NIH grants NS-40144, NS-40810, NS-22576, NS-34741 and NS-37766. [source]

Nordihydroguaiaretic acid induces astroglial death via glutathione depletion

Joo-Young Im
Abstract Nordihydroguaiaretic acid (NDGA) is known to cause cell death in certain cell types that is independent of its activity as a lipoxygenase inhibitor; however, the underlying mechanisms are not fully understood. In the present study, we examined the cellular responses of cultured primary astroglia to NDGA treatment. Continuous treatment of primary astroglia with 30 ,M NDGA caused >85% cell death within 24 hr. Cotreatment with the lipoxygenase products 5-HETE, 12-HETE, and 15-HETE did not override the cytotoxic effects of NDGA. In assays employing the mitochondrial membrane potential-sensitive dye JC-1, NDGA was found to induce a rapid and almost complete loss of mitochondrial membrane potential. However, the mitochondrial permeability transition pore inhibitors cyclosporin A and bongkrekic acid did not block NDGA-induced astroglial death. We found that treatment with N-acetyl cysteine (NAC), glutathione (GSH), and GSH ethyl ester (GSH-EE) did inhibit NDGA-induced astroglial death. Consistently, NDGA-induced astroglial death proceeded in parallel with intracellular GSH depletion. Pretreatment with GSH-EE and NAC did not block NDGA-induced mitochondrial membrane potential loss, and there was no evidence that reactive oxygen species (ROS) production was involved in NDGA-induced astroglial death. Together, these results suggest that NDGA-induced astroglial death occurs via a mechanism that involves GSH depletion independent of lipoxygenase activity inhibition and ROS stress. 2007 Wiley-Liss, Inc. [source]

The validity and internal structure of the Bipolar Depression Rating Scale: data from a clinical trial of N-acetylcysteine as adjunctive therapy in bipolar disorder

Michael Berk
Berk M, Dodd S, Dean OM, Kohlmann K, Berk L, Malhi GS. The validity and internal structure of the Bipolar Depression Rating Scale: data from a clinical trial of N-acetylcysteine as adjunctive therapy in bipolar disorder. Background: The phenomenology of unipolar and bipolar disorders differ in a number of ways, such as the presence of mixed states and atypical features. Conventional depression rating instruments are designed to capture the characteristics of unipolar depression and have limitations in capturing the breadth of bipolar disorder. Method: The Bipolar Depression Rating Scale (BDRS) was administered together with the Montgomery Asberg Rating Scale (MADRS) and Young Mania Rating Scale (YMRS) in a double-blind randomised placebo-controlled clinical trial of N-acetyl cysteine for bipolar disorder (N = 75). Results: A factor analysis showed a two-factor solution: depression and mixed symptom clusters. The BDRS has strong internal consistency (Cronbach's alpha = 0.917), the depression cluster showed robust correlation with the MADRS (r = 0.865) and the mixed subscale correlated with the YMRS (r = 0.750). Conclusion: The BDRS has good internal validity and inter-rater reliability and is sensitive to change in the context of a clinical trial. [source]