instruction:
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.
question:
The local anesthetic properties of tetrodotoxin, a potent naturally occurring sodium channel blocker, have been recently reexamined. It was found that sciatic nerve block duration could be greatly increased and systemic toxicity greatly decreased if epinephrine was injected with tetrodotoxin. The mechanism that underlies epinephrine-mediated prolongation of tetrodotoxin nerve blocks is not known, but indirect evidence suggests that epinephrine may slow the clearance of tetrodotoxin from the site of injection. The authors hypothesized that tetrodotoxin causes vasodilatation at its injection site, which accelerates its systemic uptake, and that this vasodilatation is attenuated by coinjected epinephrine.', 'The radiolabeled microsphere technique was used to measure tissue blood flow in anesthetized rats before and after perisciatic injection of tetrodotoxin alone and in combination with epinephrine.', 'Tetrodotoxin, in a dose of 0.1 ml of a 60 microM solution, significantly increased blood flow in perisciatic muscle at the injected side compared with simultaneous contralateral control and ipsilateral preinjection baseline. Tetrodotoxin did not increase blood flow in the sciatic nerve. Coinjection of epinephrine with tetrodotoxin prevented tetrodotoxin-induced increases in perisciatic muscle blood flow over time and did not alter sciatic nerve blood flow. Arterial blood pressure was maintained with this dose of tetrodotoxin, although brain blood flow decreased. Coinjection of epinephrine with tetrodotoxin prevented decreases in brain blood flow. Higher doses of tetrodotoxin produced hypotension.
answer:
Does epinephrine prevent muscle blood flow increases after perineural injection of tetrodotoxin?


question:
A fundamental prerequisite for using degradable synthetic biopolymers as composite skin substitutes is the ability to establish vascular tissue. PEGT/PBT block-copolymer matrices have previously been shown as a favorable dermal substitute. In this study, quantitative data on neovascularization of PEGT/PBT block-copolymer matrices are presented.', 'PEGT/PBT-block-copolymer discs of three different pore diameters (1: < 75 microm, 2: 75-212 microm, 3: 250-300 microm) were implanted into dorsal skinfold chambers of balb/c mice. Histological sections were evaluated 7, 14, and 21 days post implantation by light and scanning electron microscopy. Blood vessel analysis was performed by means of digital image analysis (n = 288) of hematoxylin/eosin stained sections within apical (AOF) and basal (BOF) observation fields of the matrices.', 'Twenty-one days after implantation the density of blood vessels within the BOF of the scaffolds with a pore size of 75-212 and 250-300 microm were 4.6 +/- 0.45 and 5.8 +/- 0.62 (mean +/- S.E.M.; blood vessel profiles (BVF)), respectively. In <75 microm scaffolds, smaller numbers of BVF were found (4.2 +/- 0.39). In contrast, the evaluation within the AOF revealed significantly higher numbers of BVF in 75-212 microm group (3.5 +/- 0.49) and 250-300 microm group (4.5 +/- 0.66) as compared to the < 75 microm group (2.3 +/- 0.48).
answer:
Does analysis of neovascularization of PEGT/PBT-copolymer dermis substitute in balb/c-mice?


question:
pulmonary rehabilitation (PR) improves health status and exercise tolerance, but not respiratory function in patients with chronic obstructive pulmonary disease (COPD). Our objective was to identify predictors of improvement in the 6-min walked distance (6'WD) in elderly COPD patients after PR.", "this was a prospective observational study performed in an ambulatory rehabilitation setting. We enrolled 74 patients aged 65-83 years (mean: 74.2, SD: 4.4) with stable COPD in GOLD stage 3-4. About half (45.6%) of them had a basal O(2) saturation of 90% or less. After a baseline multi-dimensional assessment, patients underwent a 20-session rehabilitation cycle including training of the upper and lower extremities, and respiratory exercises, along with education sessions. The difference between final and basal 6'WD was expressed as a per cent of the basal value (6'WD gain). Patients were divided into two groups according to whether the 6'WD gain was above or under the 75th percentile, corresponding to 33% gain.", "patients whose 6'WD improved more had lower baseline forced expiratory volume in the first second (FEV1)/forced vital capacity (FVC) (46.0 versus 52.2%, P = 0.03) and baseline 6'WD, both as an absolute value (329.5 versus 408.9 m, P = 0.01) and as a per cent of the predicted (71.1 versus 93.5%, P = 0.002). After correction for potential confounders, baseline 6'WD was the only variable associated with the outcome (OR for 5% increments: 0.79; 95% CI 0.65-0.95).
answer:

Does age hamper the response to pulmonary rehabilitation of COPD patients?