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: To study the gastroprotective effect and in vivo antioxidant potential of a standardized iridoid fraction from B. prionitis leaves (BPE) against different gastric ulcer models in rats.', 'The standardized iridoid fraction from BPE at 50, 100, and 200 mg/kg body weight was administered orally, twice daily for 5 days for prevention from aspirin, ethanol, cold-restraint stress (CRS), and pylorus ligation (PL)-induced ulcers. Estimation of the antioxidant enzyme activity was carried out in a CRS-induced ulcer model, and various gastric secretion parameters including volume of gastric juice, acid output, and pH value were estimated in the PL-induced ulcer model.', 'BPE showed a dose-dependent ulcer protective effect in PL (18.67%-66.26% protection), aspirin (24.65%-63.25% protection), CRS (20.77%-59.42% protection), and EtOH (16.93%-77.04% protection)-induced ulcers. BPE treatment in PL-rats showed a decrease in acid-pepsin secretion, and enhanced mucin and mucosal glycoproteins. However, BPE reduced the ulcer index with significant decrease in LPO (P < 0.01-0.001), SOD (P < 0.01-0.001), and an increase in CAT (P < 0.01-0.001), activity in the CRS-induced model.
Answer: The data shows that the iridoid fraction from BPE possesses anti-ulcerogenic and antioxidant potential.

Output: Does gastroprotective effect of the iridoid fraction from Barleria prionitis leave on experimentally-induced gastric ulceration?


Input: Consider Input: Context: Genistein, a soy component, has been shown to have a biphasic proliferative effect in breast cancer cells, inhibiting in vitro cell proliferation at high concentrations (>10 micromol/l), while stimulating cell proliferation at lower concentrations (<10 micromol/l). However, epidemiological studies have shown an inverse correlation between the intake of genistein and the incidence of breast cancer. One of the possible reasons for this discrepancy could be the differing status of the estrogen receptor (ERalpha and/or ERbeta). Genistein selectively binds to ERbeta with strong affinity and thereby could be a potential chemotherapeutic agent against breast cancer of the ERalpha-negative and ERbeta-positive type. Therefore, the objective of the present study was to determine whether the proliferative effects of genistein were caused by its activity as a selective ERbeta agonist or merely as an antiestrogen.', 'This study was carried out in MDA-MB-231 (ERbeta) and T47D (ERalpha and ERbeta) human breast cancer cells. Cell proliferation was determined by the MTT (3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazolium bromide) assay. The cells were grown in estrogen-starved media and exposed to genistein at different concentrations for 72 h, either in the presence or absence of 17beta-estradiol.', 'A significant decrease in cell proliferation was seen in MDA-MB-231 cells at low concentrations of genistein in the presence of 17beta-estradiol, as compared to genistein alone. In T47D cells, which are known to have a predominance of ERalpha over ERbeta, genistein showed a biphasic cell proliferative response both in the presence and absence of 17beta-estradiol.
Answer: Our results suggest that in cells with a predominance of ERalpha, genistein acts as an agonist to ERalpha, and in cells with ERbeta alone, genistein most likely acts as an antiestrogen. Our results also suggest that genistein could be useful as a chemotherapeutic agent in premenopausal women with breast cancer of the ERalpha-negative and ERbeta-positive type.


Output: Does genistein in the presence of 17beta-estradiol inhibit proliferation of ERbeta breast cancer cells?