Given a passage, 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.

Input: Consider Input: In chronic pain, increased activity from intact or damaged peripheral nerve endings results in an enhanced response in central pain transmission systems, a mechanism known as central sensitization. Central sensitization can also be invoked in human experimental models. Therefore, these models may be useful to characterize novel analgesics in humans. The anticonvulsant gabapentin has demonstrated efficacy in patients with neuropathic pain, but its mode of action remains unclear. This study examined the effects of gabapentin on signs of central sensitization (brush and pinprick hyperalgesia) in a human model of capsaicin-evoked pain, using a gabapentin dosing regimen similar to that used in the clinic. The aims were to determine whether gabapentin, dosed in a manner similar to that used in the clinic, affected the various components of central sensitization and to assess the utility of this model for characterizing novel analgesics.', 'Intradermal capsaicin (100 microg/20 microl) was administered in the volar forearm of 41 male human volunteers to induce pain and clinical signs of central sensitization. Gabapentin (titrated to 2,400 mg daily) or placebo was given orally for 15 days in a randomized, double-blind, parallel-group design. The capsaicin test was conducted at baseline and after gabapentin or placebo. Endpoints were the size of areas of brush-evoked allodynia (with cotton gauze) and pinprick hyperalgesia (with von Frey filament), and the intensity of ongoing brush- and pinprick-evoked pain.', 'Gabapentin significantly reduced the area of brush allodynia compared with placebo (P </= 0.05) and insignificantly attenuated the area of pinprick hyperalgesia. Gabapentin had no significant effect on spontaneous and evoked pain intensity.

Output: Does chronic oral gabapentin reduce elements of central sensitization in human experimental hyperalgesia?

Input: Consider Input: To compare the safety and success of a retrograde approach using a microcatheter vs. a sheath in the treatment of superficial femoral artery (SFA) chronic total occlusions (CTOs).', 'From April 2007 to December 2012, 188 consecutive patients underwent EVT for 229 de novo SFA CTOs using the retrograde approach in 68 patients (35 men; mean age 72 years). This cohort was divided into cases performed with a 4-F or 6-F sheath (n=28, 36 limbs) and those with a 2.1-F microcatheter (n=35, 49 limbs). The primary outcomes were mean time to hemostasis and number of intra- and postoperative puncture site complications, as well as the success of popliteal artery puncture, lesion crossing, and reperfusion.', 'There were no significant differences between two groups in baseline characteristics. PA puncture was successful in all limbs, and the success in crossing the lesion with the wire was not significantly different (91.9% in the sheath group vs. 89.8% in the microcatheter group). Mean time to hemostasis was 8.98.8 minutes in the microcatheter group vs. 47.713 minutes in the sheath group (p<0.0001). There was a significant difference in intraoperative and postoperative complications (22.2% in the sheath group vs. 2.0% in the microcatheter group, p=0.002).

Output: Is a sheathless retrograde approach via the popliteal artery useful and safe for treating chronic total occlusions in the superficial femoral artery?

Input: Consider Input: BACKGROUND/AIMs: Pleiotrophin (PTN) have been demonstrated to play an important role in the development of human gastric cancer. However, the prognostic value remains unclear. The aim of this study was to investigate whether expression of PTN has prognostic relevance in human gastric cancer.', 'Immunohistochemistry was used to investigate the expression of PTN proteins in 178 patients with gastric cancer. The level of PTN mRNA in gastric cancer tissues and paratumor tissues were evaluated in 52 paired cases by quantitative real-time polymerase chainreaction(qRT-PCR). Survival analysis by the Kaplan-Meier method was performed to assess prognostic significance.', 'The expression level of PTN in gastric cancer tissues was significantly higher (P<0.001) than those in paratumor tissues according to the immunohistochemistry analysis, which was confirmed by qRT-PCR analysis. Additionally, the overexpression of PTN was significantly associated with the tumor site (P=0.001), Lauren's classification (P<0.001),histologic differentiation(P=0.014),depth of invasion(P<0.001), TNM stage (P=0.003),and lymph node metastasis (P=0.002). Moreover, the Cox proportional- hazards regression analysis revealed that the increased expression of PTN was an independent prognostic factor for poor recurrence-free survival(RFS) and overall survival(OS)(both P<0.001).
Output: Is increased expression of pleiotrophin a prognostic marker for patients with gastric cancer?