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.

[Q]: Context: Plasma high-density lipoprotein (HDL) level is inversely correlated with the risk of atherosclerosis. However, the cellular mechanism by which HDL exerts antiatherogenic actions is not well understood. In this study, we focus on the lipid components of HDL as mediators of the lipoprotein-induced antiatherogenic actions.', 'HDL and sphingosine 1-phosphate (S1P) stimulated the migration and survival of human umbilical vein endothelial cells. These responses to HDL and S1P were almost completely inhibited by pertussis toxin and other specific inhibitors for intracellular signaling pathways, although the inhibition profiles of migration and survival were different. The HDL-stimulated migration and survival of the cells were markedly inhibited by antisense oligonucleotides against the S1P receptors EDG-1/S1P1 and EDG-3/S1P3. Cell migration was sensitive to both receptors, but cell survival was exclusively sensitive to S1P1. The S1P-rich fraction and chromatographically purified S1P from HDL stimulated cell migration, but the rest of the fraction did not, as was the case of the cell survival.\Question: Does high-density lipoprotein stimulate endothelial cell migration and survival through sphingosine 1-phosphate and its receptors?
[A]: HDL-induced endothelial cell migration and survival may be mediated by the lipoprotein component S1P and the lipid receptors S1P1 and S1P3.


[Q]: Context: To test the hypothesis that effective pulmonary capillary blood flow can be a useful indicator for estimating appropriate oxygenation and ventilation during one-lung ventilation in lung surgery.', 'Prospective data analysis.', 'A 770-bed general teaching hospital.', '15 ASA physical status II and III patients undergoing elective lung surgery.', 'Patients received general and thoracic epidural anesthesia and underwent lung operation with one-lung ventilation.', 'We measured effective pulmonary capillary blood flow by a partial CO2 rebreathing method and oxygenation parameters during two-lung ventilation before surgery, during one-lung ventilation, and during two-lung ventilation after lung surgery.', 'The effective pulmonary capillary blood flow index significantly decreased by 31.6%, which was associated with a significant decrease in arterial oxygen tension (PaO2). The pulmonary shunt fraction increased to 46.3% during one-lung ventilation. During two-lung ventilation, after chest closure, effective pulmonary capillary blood flow index divided by heart rate (i.e., effective pulmonary blood stroke flow index) was still significantly lower than that seen during two-lung ventilation before thoracotomy. There were significant correlations between effective pulmonary capillary blood flow, pulmonary blood stroke flow index, and PaO2.\Question: Is a noninvasive partial carbon dioxide rebreathing technique for measurement of pulmonary capillary blood flow also a useful oxygenation monitor during one-lung ventilation?
[A]: Effective pulmonary capillary blood flow index and effective pulmonary blood stroke flow index are useful indicators for determining appropriate oxygenation therapy during one-lung ventilation.


[Q]: Context: 18β-glycyrrhetinic acid (18β-GA) has multiple beneficial and therapeutic effects. However, its protective roles on methotrexate (MTX)-induced renal injury are not well defined. In the present study, we investigated the possible protective effects of 18β-GA against MTX-induced nephrotoxicity in rats.', '18β-GA (50 and 100\u2009mg/kg) was administered for 7 days either before or after MTX. The rats were decapitated and kidney and serum samples were collected.', 'MTX-induced renal injury in rats was evidenced by the significant (p\u2009<\u20090.001) increase in circulating kidney function markers and tumor necrosis factor alpha (TNF-α), as well as the histopathological alterations. MTX-induced rats exhibited significantly increased lipid peroxidation (p\u2009<\u20090.05) and nitric oxide (p\u2009<\u20090.001) levels, with concomitant marked (p\u2009<\u20090.001) decline in the antioxidant defenses. 18β-GA, administered either before or after MTX, produced a significant amelioration of circulating kidney function markers, TNF-α, kidney lipid peroxidation, nitric oxide, and antioxidant defenses. In addition, 18β-GA supplementation significantly up-regulated the mRNA abundance of both nuclear factor-erythroid 2-related factor 2 (Nrf2) and hemoxygenase 1 (HO-1) in the kidney of MTX-induced rats.\Question: Does 18β-Glycyrrhetinic acid protect against methotrexate-induced kidney injury by up-regulating the Nrf2/ARE/HO-1 pathway and endogenous antioxidants?
[A]:
These results indicate that 18β-GA has a protective effect on MTX-induced nephrotoxicity with possible mechanisms of attenuating oxidative stress and inflammation through up-regulating the Nrf2/ARE signaling. These findings make 18β-GA candidate as a potent agent in preventing MTX-induced kidney injury.