In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
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Question: Context: In our initial attempt to identify differentiation markers for ocular surface epithelia, we observed a unique staining pattern by a commercial anti-Galphaq antibody. We further isolate and characterize the protein reactive with this anti-Galphaq antibody in human ocular surface epithelia.', 'Human donor corneoscleral buttons were sectioned and stained with a battery of commercial antibodies against Galpha proteins. Western blot analysis of cell lysates of corneal epithelial cells and HEK 293 cells transfected with Galphaq cDNA was used to determine the identity of the protein reactive with the anti-Galphaq antibody (E-17). Comparisons were made with another anti-Galphaq antibody (G4415) and an anti-cytokeratin 12C (J7) antibody. The isolated proteins reactive with E17 and J7 were then analyzed with two dimensional isoelectric focusing. Polypeptide sequences were identified using matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) after in-gel protein digestion.', 'The E-17 anti-Galphaq antibody preferentially stained the entire corneal epithelia and the suprabasal layers of the limbus with complete absence of staining in the basal limbus and conjunctiva. Western blot analysis of corneal epithelial cells showed that E-17 antibody identified a protein with a molecular weight of 55 kDa. However, the antibody did not react with the purported antigen, Galphaq protein (42 kDa) produced by Galphaq cDNA. Another anti-Galphaq antibody (G4415) did not react with the 55 kDa protein but did react with the 42 kDa Galphaq protein. Further comparison of the E-17 antibody with the J7 antibody revealed that both recognized the 55 kDa band in one and two dimensional analysis. MALDI-TOF MS analysis confirmed that the 55 kDa protein of interest was actually cytokeratin 12 (CK12), rather than Galphaq protein.\Question: Is cytokeratin 12 in human ocular surface epithelia the antigen reactive with a commercial anti-Galpha q antibody?

Answer: The commercial E-17 anti-Galphaq antibody did not react with Galphaq protein, its purported antigen. Instead, it recognized a 55 kDa protein, which was characterized to be cytokeratin 12 by isoelectric focusing and peptide fingerprinting with mass spectrometry. Based on its reactivity with CK12, this commercial E-17 can be used as a differentiation marker to study ocular surface epithelia.


Question: Context: Peritoneal dialysis is complicated by mesothelial cell injury due to low biocompatibility of peritoneal dialysis fluid (PDF). We have previously demonstrated that heat shock protein (HSP)-72 is potently up-regulated in response to PDF exposure of mesothelial cells in in vitro and in vivo models of peritoneal dialysis. The aim of this study was to evaluate potential cytoprotective effects of overexpression of HSP-72.', 'Cytoprotection was assessed by comparing cellular viability between pretreated versus nonpretreated human mesothelial cells (Met 5a; ATCC, Manassas, VA, USA, and primary cell cultures) subjected to extended, usually lethal PDF exposure times (120 min, CAPD2; Fresenius, Bad Homburg, Germany). Pretreatment was performed with exposure to PDF (60 min, CAPD2; Fresenius) or heat (15 min, 41.5 degrees C), and by transient transfection with HSP-72.', 'When mesothelial cells were pretreated by nonlethal exposure to PDF or heat, HSP-72 was markedly up-regulated (>5-fold, P < 0.01). Pretreated human mesothelial cells were significantly protected against subsequent "lethal" exposures to PDF, as assessed by dye exclusion (>50% reduction, P < 0.05) and lactate dehydrogenase (LDH) release (>30% reduction, P < 0.05). Comparable cytoprotection (50% reduction by dye exclusion) was indicated by overexpression of HSP-72 in cultered human mesothelial cells (>5-fold) after transient transfection with HSP-72. This cytoprotection was confirmed at a cellular basis by double staining techniques with HSP-72 and ApopTag (apoptosis detection kit).\Question: Does overexpression of HSP-72 confer cytoprotection in experimental peritoneal dialysis?

Answer: Our study therefore shows that the mesothelial stress response confers cytoprotection in experimental peritoneal dialysis, mediated by the induction of HSP-72, and that the stimulus of the pretreatment does not have to be identical to the subsequent injury. These data offer the basis for an attractive novel therapeutic approach against PDF toxicity.


Question: Context: The deficiency of glutathione (GSH) has been linked to several diseases. The study investigated the role of GSH as a protective factor against hyperglycemia-mediated injury in VL-17A cells treated with 50 mM glucose.', 'The cell viability and different oxidative stress parameters including glyoxalase I activity were measured.', 'GSH supplementation with 2 mM N-acetyl cysteine (NAC) or 0.1 mM ursodeoxycholic acid (UDCA) increased the viability, GSH level and the GSH-dependent glyoxalase I activity in 50 mM glucose-treated VL-17A cells. Further, pretreatment of 50 mM glucose-treated VL-17A cells with NAC or UDCA decreased oxidative stress (levels of reactive oxygen species and protein carbonylation), apoptosis (caspase 3 activity and annexin V-propidium iodide positive cells) and glutathionylated protein formation, a measure of oxidative stress. GSH depletion with 0.4 mM buthionine sulfoximine (BSO) or 1 mM diethyl maleate (DEM) potentiated the decrease in viability, glyoxalase I activity and increase in oxidative stress and apoptosis, with decreased GSH levels in 50 mM glucose-treated VL-17A cells.\Question: Does gSH protect against oxidative stress and toxicity in VL-17A cells exposed to high glucose?

Answer:
Thus, changes in GSH levels with exogenous agents such as NAC, UDCA, BSO or DEM modulate hyperglycemia-mediated injury in a cell model of VL-17A liver cells.