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: The pulmonary endothelium plays an important role in the metabolism of the amino acid arginine, the exclusive precursor molecule for nitric oxide (NO). Despite decreased circulating arginine levels, endothelial NO production is elevated during endotoxemia. However, the regulation of pulmonary artery endothelial arginine transport has not been studied. We hypothesized that endotoxin stimulates carrier-mediated arginine transport by the pulmonary endothelium.', 'The relative contributions of the various transport systems to total arginine transport by porcine pulmonary artery endothelial cells (PAECs) was determined by assaying the uptake of 3H-L-arginine in the presence or absence of Na+. PAECs were then incubated with various concentrations of Escherichia coli endotoxin, and y(+)-mediated arginine transport was measured at different time points thereafter. Kinetic studies were performed over a range of arginine concentrations to determine changes in transport affinity and maximum rate of metabolism. To address the role of RNA and protein synthesis in the increased transport, uptake was measured after exposure of cells to the transcriptional inhibitor actinomycin D and the protein synthesis inhibitor cycloheximide.', 'Most (75%) of arginine transport by PAECs was mediated by the high-affinity Na(+)-independent transport system y+. Endotoxin stimulated y(+)-mediated arginine transport by PAECs twofold to fivefold, a response that was time and dose dependent. The accelerated transport was detectable within 2 hours and maximal at 12 hours. Kinetic studies revealed that the accelerated arginine transport was the result of a 68% increase in the maximal transport velocity (1519 +/- 65 pmol/mg protein/30 sec in endotoxin-treated cells vs 903 +/- 96 in control cells; p < 0.01) without a change in transport affinity. The endotoxin-mediated increase in arginine uptake was abrogated by actinomycin D and cycloheximide.\Question: Does endotoxin stimulate arginine transport in pulmonary artery endothelial cells?

A: Endotoxin stimulates Na(+)-independent arginine transport by PAECs through a process that requires de novo RNA and protein synthesis, possibly of the transporter itself. This response may be designed to support arginine-dependent biosynthetic pathways in the lung during septic states.
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Q: Context: Intravenous tissue-type plasminogen activator (tPA) is a proven treatment for acute ischemic stroke, but there has been limited evaluation among patients aged ≥90 years.', 'We analyzed data from the Get With The Guidelines-Stroke national quality improvement registry from January 2009 to April 2013. Frequency, determinants, and outcomes of tPA use were compared among patients aged ≥90 and 3 younger age groups (18-64, 65-79, and 80-89 years).', 'Among 35\u2009708 patients from 1178 sites who arrived within 2 hours of time last known well and received tPA, 2585 (7.2%) were ≥90 years. Compared with younger patients, the rate of tPA use among patients without a documented contraindication was lower among patients aged ≥90 years (67.4% versus 84.1% in 18-89-year olds; P<0.0001). Discharge outcomes among individuals aged ≥90 years included discharge to home or acute rehabilitation in 31.4%, independent ambulation at discharge in 13.4%, symptomatic hemorrhage in 6.1%, and in-hospital mortality or hospice discharge in 36.4%. On multivariable analysis, good functional outcomes generally occurred less often and mortality more often among patients aged ≥90 years. The risk of symptomatic hemorrhage was increased compared with patients <65 years but was not significantly different than the risk in 66- to 89-year olds.\Question: Do use and Outcomes of Intravenous Thrombolysis for Acute Ischemic Stroke in Patients ≥90 Years of Age?

A: The use of intravenous tPA among those aged ≥90 years is lower than in younger patients. When fibrinolytic therapy is used, the risk of symptomatic hemorrhage is not higher than in 66- to 89-year olds; however, mortality is higher and functional outcomes are lower.
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Q: Context: Adipose tissue derived-mesenchymal stem cells (AMSCs) are one of the most widely used MSCs in the cell therapy for regenerative medicine. In the current study, the role of CXCL13 in AMSCs and its potential signaling pathway were investigated.', 'AMSCs were isolated from adipose tissue of healthy subjects. After administrating the cells with CXCL13, the expression levels of miR-23a and runt-related transcription factor 2 (Runx2) were assessed by real-time PCR and western blot. The alterations of phosphoinositide-3 kinase (PI3K)/Akt, stress-activated protein kinase (SAPK)/c-jun kinase (JNK), and extracellular-signal-regulated kinase (ERK1/2) pathways were also evaluated.', 'CXCL13 down-regulated miR-23a and up-regulated Runx2 expression in AMSCs. The inhibitor specific for PI3K/AKT, but not SAPK/JNK and ERK ERK1/2, reversed the effects of CXCL13 on miR-23a and Runx2 expression.\Question: Does cXCL13 inhibit microRNA-23a through PI3K/AKT signaling pathway in adipose tissue derived-mesenchymal stem cells?

A:
CXCL13 inhibits miR-23a expression through modulating PI3K/AKT pathway in AMSCs.
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