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.

Q: Context: Current views on the control of cell development are anchored on the notion that phenotypes are defined by networks of transcriptional activity. The large amounts of information brought about by transcriptomics should allow the definition of these networks through the analysis of cell-specific transcriptional signatures. Here we test this principle by applying an analogue to comparative anatomy at the cellular level, searching for conserved transcriptional signatures, or conserved small gene-regulatory networks (GRNs) on root hairs (RH) and pollen tubes (PT), two filamentous apical growing cells that are a striking example of conservation of structure and function in plants.', 'We developed a new method for isolation of growing and mature root hair cells, analysed their transcriptome by microarray analysis, and further compared it with pollen and other single cell transcriptomics data. Principal component analysis shows a statistical relation between the datasets of RHs and PTs which is suggestive of a common transcriptional profile pattern for the apical growing cells in a plant, with overlapping profiles and clear similarities at the level of small GTPases, vesicle-mediated transport and various specific metabolic responses. Furthermore, cis-regulatory element analysis of co-regulated genes between RHs and PTs revealed conserved binding sequences that are likely required for the expression of genes comprising the apical signature. This included a significant occurrence of motifs associated to a defined transcriptional response upon anaerobiosis.
Answer: Our results suggest that maintaining apical growth mechanisms synchronized with energy yielding might require a combinatorial network of transcriptional regulation. We propose that this study should constitute the foundation for further genetic and physiological dissection of the mechanisms underlying apical growth of plant cells.

A: Does transcriptional profiling of Arabidopsis root hairs and pollen define an apical cell growth signature?
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Q: Context: Before desflurane is advocated for patients undergoing neurosurgical procedures, it is necessary to determine the effect of desflurane on cerebral blood flow (CBF). In this study, CBF values are compared between desflurane and isoflurane at two doses. In addition, CBF reactivity to CO2 and the effect of prolonged exposure were compared between the two agents.', 'Cerebral blood flow measurements with intravenous 133Xe were performed in 24 patients undergoing craniotomy for mass lesions, randomized to receive either isoflurane or desflurane in oxygen and air. Cerebral blood flow was determined at 1 and 1.5 MAC concentrations at PaCO2 of 25 mmHg in the absence of surgical stimulation. Intraoperatively, with 1.25 MAC anesthesia, CBF was determined at target PaCO2 of 25 and 35 mmHg. In 15 patients, an additional measurement at 1.25 MAC was made before closure.', 'At 1.0 MAC, mean +/- SD CBF values for the desflurane and isoflurane groups were 18 +/- 2 and 20 +/- 3 ml x 100 g-1 x min-1, respectively. At 1.5 MAC, CBF values were the same for the two anesthetics; 17 +/- 3 ml x 100 g-1 x min-1 for isoflurane and 19 +/- 4 ml.100 g-1 x min-1 for desflurane. During 1.25 MAC anesthesia, there were no differences between groups, with CO2 reactivity 1.3 +/- 1.2 ml x 100 g-1 x min-1 x mmHg-1 for desflurane and 1.6 +/- 0.6 ml.100 g-1 x min-1 x mmHg-1 for isoflurane. There was no demonstrable decrease in CBF with prolonged exposure to either agent.
Answer: Desflurane and isoflurane are similar in terms of absolute CBF, the response to increasing doses, and the preservation of CO2 reactivity.

A: Do desflurane and isoflurane have similar effects on cerebral blood flow in patients with intracranial mass lesions?
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Q: Context: Methotrexate (MTX) is the anchor drug in the treatment of patients with rheumatoid arthritis (RA). MTX shows effects on disease activity and mortality. However, it is unclear whether the effect of MTX on mortality depends on its effect on disease activity.', 'In a post-hoc analysis we analysed the data of our cohort established in Ratingen, Germany, and included all patients starting treatment with MTX (n=271) between 1980 and 1987. One year after baseline (BL), response to MTX treatment was assessed using a modified ACR 20 response. Follow-up data of 250 patients were available after 10 and 18 years.', 'After 1 year, there were 66% responders and 20% non-responders; only 14% had discontinued MTX treatment due to side effects or lack of efficacy. Most patients continued MTX treatment irrespective of efficacy. Ten years after BL, 61% of the patients were still treated with MTX. After 18 years, the responder-group showed a standardised mortality ratio of 1.6 compared to 3.2 for the group of non-responders. However, when adjusting for age, gender, response to MTX treatment one year after BL, number of swollen joints and comorbidities after 10 years an independent association of continued MTX treatment with lower mortality was found for the period 10 to 18 years after BL (hazard ratio (HR): 0.63, 95% confidence interval: 0.43-0.92, p=0.015).
Answer: In this cohort, the mortality lowering effect of continued MTX use was partly independent of its effect on disease activity. This finding may affect treatment decisions concerning RA patients with insufficient response to MTX.

A:
Is the positive influence of methotrexate on the mortality of patients with rheumatoid arthritis partly independent of its effect on disease activity : results of a re-evaluation 18 years after baseline?
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