TASK DEFINITION: Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.
PROBLEM: 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.
Answer: 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.

SOLUTION: Does endotoxin stimulate arginine transport in pulmonary artery endothelial cells?

PROBLEM: Context: The etiology and pathogenesis of inflammatory bowel disease remain unknown. However, neutrophil infiltration into the inflammatory lesion is an important process in inflammatory bowel disease. In this study, we used rat trinitrobenzene sulfonic acid (TNBS) ileitis as a Crohn's disease model, and investigated the effects of oral IS-741 (which inhibits the expression of Mac-1, a cell adhesion molecule) on leukocyte-endothelial interactions.", 'Rat ileitis was induced by the intraluminal injection of a TNBS solution (160 mg/kg in 50% ethanol) at a site 10 cm proximal to the ileocecal valve. The rats then received oral IS-741 (50 mg/kg) or saline for 7 days. On the day 8 after the initial administration of IS-741 or saline, we determined the visible damage score, and assessed myeloperoxidase (MPO) activity. Concentrations of cytokines in the ileum, such as interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) were assayed by enzyme-linked immunosorbent assay (ELISA). We also investigated the infiltration of polymorphonuclear cells and Mac-1 positive cells by histological examinations.', 'The administration of IS-741 resulted in a significant reduction of the visible damage score, myeloperoxidase (MPO) activity, and mucosal IL-8 levels in the ileum as compared with the saline administration. IS-741 also dramatically reduced the infiltration of polymorphonuclear cells and Mac-1 positive cells into the inflamed lesions.
Answer: These results indicate that the oral administration of IS-741 inhibits neutrophil infiltration into inflamed lesions, and is effective for attenuating rat TNBS ileitis. This new anti-inflammatory agent may be beneficial for the treatment of inflammatory bowel disease.

SOLUTION: Does a novel diamino-pyridine derivative ( IS-741 ) attenuate rat ileitis induced by trinitrobenzene sulfonic acid?

PROBLEM: Context: The induction of cellular immune responses to melanocyte-specific enzymes such as the tyrosinase family of proteins is the goal of various clinical studies for the immunotherapy of melanoma. Tyrosinase-related protein-2 (TRP2) is an attractive model antigen for preclinical studies in C57BL/6 mice because it is naturally expressed by the murine B16 melanoma and can be recognized by self-reactive cytolytic T lymphocytes (CTL). Here we describe efforts to develop genetic immunization with dendritic cells (DC) for the immunotherapy of melanoma in this clinically relevant system.', 'Recombinant adenoviruses encoding green fluorescent protein (Ad-EGFP) and murine TRP2 (Ad-mTRP2) were constructed using Cre-loxP-mediated recombination. DC were generated in vitro from precursors in bone marrow and transduced with Ad-EGFP or Ad-mTRP2. Mice were immunized by direct injection of adenovirus or by injection of Ad-transduced DC. Induction of tumor immunity was assessed by intravenous challenge with B16 melanoma cells and enumeration of experimentally induced lung metastases.', 'Flowcytometric analysis of DC transduced with Ad-EGFP demonstrated endogenous fluorescence due to cytoplasmatic expression of EGFP in 30-60% of cells. Ad-EGFP-transduced DC simultaneously displayed the DC-specific marker NLDC145 and high levels of MHC and costimulatory molecules on their cell surface. Transduction of DC with Ad-mTRP2 resulted in strong intracellular expression of TRP2 which could be readily detected by immunostaining. Importantly, immunization of mice with cultured Ad-mTRP2-transduced DC completely prevented the development of lung metastases following an intravenous challenge with B16 melanoma cells. This striking protective effect was observed with both the intravenous and the subcutaneous route of DC immunization. In vivo depletion of T-cell subsets suggested that the protective effect of an immunization with Ad-mTRP2-transduced DC involved both CD8+ and CD4+ T-cells.
Answer: Our results demonstrate that DC-based genetic immunization of mice with TRP2, a clinically relevant melanocyte-specific self-antigen, induces effective cellular immunity and prevents metastatic growth of B16 melanoma cells in vivo.

SOLUTION:
Does dendritic cell-based genetic immunization in mice with a recombinant adenovirus encoding murine TRP2 induce effective anti-melanoma immunity?