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.
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Question: Context: Absenteeism from outpatient appointments is common. Telephone appointment-reminder calls reduce outpatient-appointment absenteeism in many clinic settings.', 'To determine if telephone appointment-reminder calls reduce outpatient absenteeism at a hospital-based pulmonary function laboratory.', 'We conducted a retrospective review of our pulmonary function laboratory's outpatient appointment records from April to November 2004. Data were collected from consecutive outpatient appointments, including patient age, sex, whether a telephone appointment-reminder call was successfully made, and whether the patient showed up for the scheduled test. We performed 3 analyses. Differences in absenteeism between the groups was the primary outcome measure. First, appointments were separated into 2 groups: (1) appointments for which a reminder call was attempted ("called" group) and (2) appointments for which a reminder call was not attempted ("not-called" group). The appointments were then separated into 2 further groups: (1) the reminder call was successfully achieved ("contacted" group) and (2) the patient either was not called or was called but could not be reached ("not-contacted" group). Finally, the contacted group was separated into 2 further groups: (1) reminder calls that resulted in direct conversation with an appropriate person at the patient's listed telephone number, and (2) reminder message left on an answering machine.', 'Data were collected from 515 consecutive outpatient appointments; 45 (8.7%) of these patients did not show up for testing. The absentee rate was 4.7% (n = 10) in the called group and 11.6% (n = 35) in the not-called group (p = 0.0066). In the called group, 6.5% (n = 14) could not be reached. The absentee rate was 4% (n = 8) in the contacted group and 11.7% (n = 37) in the not-contacted group (p = 0.0021). We found no difference in absenteeism between patients who received reminders via direct conversation (4.2%) and those who had a reminder message left on an answering machine (3.7%) (p > 0.05).
Answer: A policy of reminding outpatients of their appointments via telephone reduces absenteeism at a hospital-based pulmonary function laboratory. We found no difference in absenteeism between communicating the reminder via direct conversation versus via leaving a message on an answering machine.

Answer: Does the effect of telephone appointment-reminder call on outpatient absenteeism in a pulmonary function laboratory?

Question: Context: Prostaglandin D2 (PGD2) and cysteinyl leukotrienes (cysLTs) are lipid mediators derived from mast cells, which activate TH2 cells. The combination of PGD2 and cysLTs (notably cysteinyl leukotriene E4 [LTE4]) enhances TH2 cytokine production. However, the synergistic interaction of cysLTs with PGD2 in promoting TH2 cell activation is still poorly understood. The receptors for these mediators are drug targets in the treatment of allergic diseases, and hence understanding their interaction is likely to have clinical implications.', 'We aimed to comprehensively define the roles of PGD2, LTE4, and their combination in activating human TH2 cells and how such activation might allow the TH2 cells to engage downstream effectors, such as neutrophils, which contribute to the pathology of allergic responses.', 'The effects of PGD2, LTE4, and their combination on human TH2 cell gene expression were defined by using a microarray, and changes in specific inflammatory pathways were confirmed by means of PCR array, quantitative RT-PCR, ELISA, Luminex, flow cytometry, and functional assays, including analysis of downstream neutrophil activation. Blockade of PGD2 and LTE4 was tested by using TM30089, an antagonist of chemoattractant receptor-homologous molecule expressed on TH2 cells, and montelukast, an antagonist of cysteinyl leukotriene receptor 1.', 'PGD2 and LTE4 altered the transcription of a wide range of genes and induced diverse functional responses in TH2 cells, including cell adhesion, migration, and survival and cytokine production. The combination of these lipids synergistically or additively enhanced TH2 responses and, strikingly, induced marked production of diverse nonclassical TH2 inflammatory mediators, including IL-22, IL-8, and GM-CSF, at concentrations sufficient to affect neutrophil activation.
Answer: PGD2 and LTE4 activate TH2 cells through different pathways but act synergistically to promote multiple downstream effector functions, including neutrophil migration and survival. Combined inhibition of both PGD2 and LTE4 pathways might provide an effective therapeutic strategy for allergic responses, particularly those involving interaction between TH2 cells and neutrophils, such as in patients with severe asthma.

Answer: Do prostaglandin D2 and leukotriene E4 synergize to stimulate diverse TH2 functions and TH2 cell/neutrophil crosstalk?

Question: Context: Nonviral vectors based on polyethylenimine (PEI) usually contain an excess of PEI that is not complexed to DNA. Since unbound PEI contributes to cellular and systemic toxicity, purification of polyplexes from unbound PEI is desirable.', 'Size exclusion chromatography (SEC) was used to purify PEI polyplexes of free PEI. Transfection properties of purified polyplexes and the effect of free PEI on gene delivery were studied in vitro and in vivo after systemic application into mice.', 'SEC did not change the size and zeta-potential of polyplexes. Independent of the amount of PEI used for complex formation, purified PEI polyplexes had the same final PEI nitrogen/DNA phosphate ratio of 2.5. Notably, purified PEI polyplexes demonstrated low cellular and systemic toxicity. High transfection efficiency was achieved with purified polyplexes at high DNA concentrations (8-15 microg/ml). At low DNA concentrations (2-4 microg/ml) gene transfer with purified particles was less efficient than with polyplexes containing free PEI both in vitro and in vivo. Mechanistic studies showed that free PEI partly blocked cellular association of DNA complexes but was essential for the following intracellular gene delivery. Adding free PEI to cells treated with purified particles with a delay of up to 4 h resulted in significantly enhanced transfection efficiency compared with non-purified particles or purified particles without free PEI.
Answer: This study presents an efficient method to remove free PEI from PEI polyplexes by SEC. Our results from transfection experiments demonstrate that free PEI substantially contributes to efficient gene expression but also mediates toxic effects in a dose-dependent manner. Purified polyplexes without free PEI have to be applied at increased concentrations to achieve high transfection levels, but exhibit a greatly improved toxicity profile.

Answer:
Does purification of polyethylenimine polyplexes highlight the role of free polycations in gene transfer?