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.

Input: Consider Input: Context: Disruptions to intermyocyte coupling have been implicated in arrhythmogenesis and development of conduction disturbances. At present, understanding of the relationship between the microscopic organization of intercellular coupling and the macroscopic spread of impulse in the normal and diseased heart is largely confined to theoretical analyses.', 'The abundance and arrangement of gap junctions, as well as conduction properties, were assessed in terminal crest preparations isolated from the atria of neonate, weanling, and adult rabbits. We report that the connexin composition of terminal crest was uncomplicated, with Cx43 being the most prominent isoform detectable by Western blotting and immunostaining. Terminal crest myocytes showed little change in total Cx43-gap junction per cell during postnatal growth as assessed by stereology. However, marked non-uniformities emerged in the sarcolemmal distribution of Cx43-gap junctions. Cx43-gap junction area at myocyte termini increased 3.5-fold from birth to adulthood. Correlated with this change in Cx43, impulse propagation velocity parallel to the myofiber axis, as assessed by multi-site optical mapping using voltage-sensitive dye (di-4-ANEPPS), increased 2.4-fold. Conversely, the amount of Cx43-gap junctions on myocyte sides, and the conduction velocity transverse to the myofiber axis, remained relatively invariant during maturation. Hence, the increasing electrical anisotropy of maturing terminal crest was wholly accounted for by increases in conductance velocity along the bundle. This increase in longitudinal conduction velocity was correlated with changes in the sarcolemmal pattern, but not the overall density, of Cx43-gap junctions.
Answer: This study provides the first correlative structure/function analysis of the relationship between the macroscopic conduction of impulse and the microscopic cellular organization of gap junctions in a differentiating cardiac bundle. Confirmation is provided for theoretical predictions which emphasize the importance of the cell-to-cell geometry of coupling in determining the spread and pattern of myocardial activation.

Output: Are the rate and anisotropy of impulse propagation in the postnatal terminal crest correlated with remodeling of Cx43 gap junction pattern?

Input: Consider Input: Context: Hyperoxia increases oxidative stress through the generation of reactive oxygen species and may therefore enhance inflammation in the lungs. The aim of this study was to investigate whether short term supplementary oxygen (28%) increases oxidative stress and inflammation in the airways by measuring 8-isoprostane and interleukin 6 (IL-6) concentrations in exhaled breath condensate.', 'Twenty three healthy subjects (12 men, mean (SD) age 48 (7) years) and 23 patients with chronic obstructive pulmonary disease (COPD; 15 men, mean (SD) age 56 (5) years) were studied. 8-isoprostane and IL-6 concentrations were measured by immunoassay.', 'Increased concentrations of 8-isoprostane and IL-6 were found in all subjects after breathing 28% oxygen for 1 hour. In healthy subjects the concentrations of 8-isoprostane and IL-6 were 10.9 (2.9) pg/ml and 4.9 (0.8) pg/ml, respectively, compared with baseline concentrations of 6.1 (1.3) pg/ml and 2.9 (0.6) pg/ml, and in patients with COPD the concentrations were 27.9 (3.1) pg/ml and 8.3 (1.2) pg/ml), respectively, compared with baseline concentrations of 18.9 (3.6) pg/ml and 6.3 (0.6) pg/ml. By contrast, breathing air through the same face mask for 1 hour had no significant effects on 8-isoprostane or IL-6 concentrations in normal subjects or those with COPD.
Answer: These findings suggest that short term supplementary oxygen may enhance oxidative stress and inflammation in the airways. Whether this happens with long term oxygen therapy needs to be determined.

Output: Does supplementary oxygen in healthy subjects and those with COPD increase oxidative stress and airway inflammation?

Input: Consider Input: Context: Left ventricular (LV) dysfunction is often found in the early stage of human immunodeficiency virus (HIV) infection and deteriorates with disease progression. CD4 lymphocyte count and opportunistic infection are the major indicators for the clinical staging of HIV infection. This study investigated the association of these indicators with LV dysfunction in the clinical course of HIV infection.', 'HIV-positive patients without cardiac manifestations consecutively admitted from May 1998 to April 1999 were enrolled in the study. Echocardiographic LV function evaluation and measurement of CD4 lymphocyte count were performed. Parameters for LV systolic and diastolic functions were compared between patients with CD4 lymphocyte count >or= 200/microL and those with CD4 < 200/microL. In patients with CD4 < 200/microL, LV function was further correlated with the presence or absence of opportunistic infections.', 'Ninety eight HIV-positive patients including 52 with CD4 >or= 200/microL and 46 with CD4 < 200/microL were studied. One half of the 46 patients with CD4 < 200/microL had active opportunistic infections. We found that LV fractional shortening, ejection fraction, and isovolumic relaxation time were all significantly lower in the patients with CD4 < 200/microL compared with those with CD4 >or= 200/microL. Moreover, these LV systolic and diastolic dysfunctions were positively correlated with decreased CD4 lymphocyte count. In contrast, no difference was found in these parameters between patients with and without opportunistic infections. In multiple regression analysis, CD4 lymphocyte count was found to be the only factor for predicting the LV systolic and diastolic dysfunction.
Answer: Both LV systolic and diastolic function deteriorate as the CD4 lymphocyte count decreases in HIV infection. Opportunistic infection seems to have a limited role in the pathogenesis of LV dysfunction in advanced HIV infection.
Output: Is left ventricular dysfunction associated with CD4 lymphocyte count rather than opportunistic infection in human immunodeficiency virus infection?