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: Postoperative neurologic deficits after thoracic aortic reconstruction vary widely. Our previous study showed that delayed ischemic preconditioning could prevent spinal cord injury caused by occlusion of the descending thoracic aorta in pigs. We investigated early ischemic preconditioning in the same model.', 'Twenty-eight pigs were divided into 4 groups: group 1 (n = 6) underwent a sham operation, group 2 (n = 6) underwent aortic occlusion for 20 minutes, group 3 (n = 8) underwent aortic occlusion for 35 minutes, and group 4 (n = 8) underwent aortic occlusion for 20 minutes and underwent aortic occlusion 80 minutes later without hypotension for 35 minutes. Aortic occlusion was accomplished by using 2 balloon occlusion catheters placed fluoroscopically at T6 to T8 above the diaphragm and at the aortic bifurcation. Neurologic evaluation was performed by an independent observer according to the Tarlov scale (0-4). The lower thoracic and lumbar spinal cords were harvested at 120 hours and examined histologically with hematoxylin-and-eosin stain. Histologic results (number of neurons and grade of inflammation) were scored (0-4) and were similarly analyzed. Statistical analysis was by means of the Kruskal-Wallis test.', 'Group 4 had a better neurologic outcome at 24, 48, and 120 hours in comparison with group 3 (P <.001). The histologic changes were proportional to the neurologic test scores, with the more severe and extensive gray matter damage in animals of group 3 (number of neurons, P <.001; grade of inflammation, P <.001).
Answer: Early ischemic preconditioning without hypotension protects against spinal cord injury after aortic occlusion, as confirmed by using the Tarlov score and histopathology.

A: Does early ischemic preconditioning without hypotension prevent spinal cord injury caused by descending thoracic aortic occlusion?
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Q: Context: To study the effect of removal of YY1 binding sites within the LCR region of HPV 16 on viral transforming activity.', 'Previously we had generated new plasmids carrying HPV 16 whole genome, which contained naturally occurred mutated LCR sequences. The viral transforming abilities on mouse fibroblasts were evaluated in anchorage-independent assays, while the expression and activity of YY1 protein in fibroblasts were tested with EMSA and luciferase assays.', 'YY1 protein was expressed in mouse fibroblasts C127, with ability for DNA binding and repression on P97 activity. Both HPV 16 wild-type DNA and mutated DNAs were transfected into C127 cells and spread to the soft-agarose mediums after selecting with G 418. The growth numbers of the cells transfected with mutated HPV 16 DNAs were 2-10 fold more than that with wild-type HPV 16 DNA.
Answer: Like in epithelial cells or cell lines, transcription regulator YY1 is widely expressed in rodent fibroblasts. Removal of YY1 binding motifs can elevate in the context of the whole genome, the anchorage independent growth ability and the transforming capacity of HPV 16 on the mouse fibroblasts.

A: Does [ Removal of YY1 binding sites in HPV 16 LCR increase viral transforming activities on mouse fibroblasts ]?
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Q: Context: This study examines the relationship between the existence of chest wall tenderness evoked by palpation and the absence of ischemic heart disease defined by myocardial perfusion imaging in patients with known or suspected stable angina pectoris.', 'Two hundred seventy-five patients were recruited. Myocardial perfusion imaging was performed on 273 of the subjects. Chest pain was classified according to type by criteria given by the Danish Society of Cardiology and severity by the Canadian Cardiovascular Society. Pectoralis major and pectoralis minor were palpated for tenderness using a standardized procedure.', 'The association between tenderness and myocardial perfusion imaging (normal vs abnormal) produced an odds ratio (OR) of 2.24 (confidence interval, 1.26-3.99; P = .009). The OR was the same magnitude and significance when stratified by sex, age, type of pain, or class. When adjusting simultaneously for sex, age, type of pain, and class, the association between tenderness and myocardial perfusion imaging (normal vs abnormal) was still present (OR = 2.57; confidence interval, 1.342-4.902; P = .004).
Answer: Presence of tenderness in the anterior chest wall is associated with a higher prevalence of normal myocardial perfusion imaging in patients with known or suspected angina pectoris, and this association cannot be explained by a common association to age, sex, or pain.

A:
Is muscular tenderness in the anterior chest wall in patients with stable angina pectoris associated with normal myocardial perfusion?
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