In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Q: Context: The bradycardic agent zatebradine (UL-FS 49) reduces heart rate without negative inotropic or proarrhythmic effects. The aim was to experimentally characterize the influence of zatebradine on arterial baroreflex sensitivity (BRS) and heart rate variability (HRV) which are generally considered as estimates of vagal activity and have prognostic value in patients after myocardial infarction (MI).', 'Conscious rats were studied 3 days after left coronary artery ligation or sham-operation (SH). BRS was determined by linear regression analysis of RR-interval and mean arterial pressure changes evoked by intravenous (i.v.) injections of methoxamine and nitroprusside. HRV at rest was calculated from high-resolution electrocardiogram-recordings.', 'In MI-rats heart rate was similar to SH-rats, mean arterial pressure was lower and both BRS and HRV were markedly reduced. Zatebradine (0.5 mg/kg i.v.) reduced heart rate in MI-rats from 400 +/- 15 to 350 +/- 19 and in SH-rats from 390 +/- 19 to 324 +/- 6 beats/min without changing mean arterial pressure. Both BRS and HRV were restored in MI- and further increased in SH-rats by the drug. Effects of 0.05, 0.5 and 5 mg/kg zatebradine revealed a dose-dependency of heart rate reduction. The lowest dose enhanced reflex bradycardia despite little effect on heart rate and lack of effect on both reflex tachycardia and HRV.\Question: Does the bradycardic agent zatebradine enhance baroreflex sensitivity and heart rate variability in rats early after myocardial infarction?

A: Both BRS and HRV are reduced in rats early after MI, indicating a depressed reflex and tonic vagal activity. Treatment with zatebradine enhances both BRS and HRV. These data suggest that the drug has both peripheral and central effects, leading to an increase of vagal control of heart rate.
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Q: Context: Dynamic pelvic magnetic resonance imaging (DP-MRI) offers a comprehensive evaluation of pelvic organ structure in addition to functional information regarding evacuation. Opportunity to apply this technology can be limited due to regional lack of availability. Ideally, clues from standard anorectal testing could predict abnormalities on DP-MRI, leading to its efficient use. The aim of this study is to determine whether high-resolution anorectal manometry (HR-ARM) correlates with findings on DP-MRI.', "This is a retrospective study of HR-ARM performed on patients with constipation who also underwent DP-MRI. Studies were reviewed for significant findings including posterior pelvic organ prolapse, rectocele\u2009>\u20093\u2009cm, rectal intussusception, and anorectal angle. Statistical analysis was performed using Pearson's correlation coefficient, Student's t-test, and Fisher's exact test.", 'Twenty-three patients undergoing HR-ARM (age range 25-78) also underwent DP-MRI. All were female; 76% were Caucasian. Twenty had significant structural findings: small pelvic prolapse (n\u2009=\u20092), moderate pelvic prolapse (n\u2009=\u200910), large pelvic prolapse (n\u2009=\u20099), rectocele (n\u2009=\u20098), or rectal intussusception (n\u2009=\u20093). Only intrarectal pressure on HR-ARM weakly correlated with size of rectocele (r\u2009=\u20090.46; P\u2009=\u20090.03) and degree of pelvic organ prolapse (r\u2009=\u20090.48; P\u2009=\u20090.02). The remainder of the HR-ARM parameters did not significantly correlate with DP-MRI findings. Patients with dyssynergy were not more likely to have rectoceles\u2009>\u20093\u2009cm (44.4% versus 35.7%; P\u2009=\u20090.5) or large prolapses (44.4% versus 50%, P\u2009=\u20091.0), compared with those without dyssynergy, on HR-ARM.\Question: Are high-resolution anorectal manometry and dynamic pelvic magnetic resonance imaging complementary technologies?

A: We were unable to find a correlation between HR-ARM findings and structural pelvic defects on DP-MRI. Therefore, these two technologies provide complementary information in the evaluation of defecatory dysfunction.
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Q: Context: To research the methods of purifying polyprenol from leaves of Ginkgo biloba L..', 'The purity of polyprenol was determined by HPLC to select the optimal purifying conditions.', 'The optimal conditions were degreased by 160 times of petroleum ether-ethyl acetate (9:1) firstly, then through a silica gel column (100-140 mesh) and eluted with petroleum etherethyl acetate (19:1).\Question: Does [ Studies on purification of polyprenol from Ginkgo biloba L. leave ]?

A:
The methods are feasible to purify polyprenol from leaves of Ginkgo biloba L. and could increase the purity of polyprenol obviously.
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