TASK DEFINITION: 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.
PROBLEM: 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?

SOLUTION: 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.

PROBLEM: Context: The PlA1/A2 polymorphism of platelet glycoprotein IIIa (GPIIIa) has been implicated in the pathogenesis of type 2 diabetes. We studied this polymorphism in a homogenous, extensively phenotyped cohort using the candidate gene approach.', 'The PlA1/A2 polymorphism was determined in 1051 patients with type 2 diabetes and in 2247 individuals without type 2 diabetes.', 'In patients with type 2 diabetes, genotype frequencies were as follows: PlA1/A1 71.4%, PlA1/A2 26.0%, and PlA2/A2 2.7%. In individuals without type 2 diabetes, genotype frequencies were 71.6%, 25.7% and 2.8%, respectively. The PlA2 allele was not associated with fasting and postprandial glucose, glycated haemoglobin, insulin, proinsulin, C-peptide and calculated indices of insulin resistance or pancreatic beta cell function. The PlA2 allele was also not significantly associated with angiographic CHD (adjusted odds ratio [OR] 1.13; 95% CI, 0.93-1.39) or with a history of previous myocardial infarction (adjusted OR 1.09; 95% CI, 0.87-1.37).\Question: Is the PlA1/A2 polymorphism of platelet glycoprotein IIIa associated with the risk of type 2 diabetes . The Ludwigshafen Risk and Cardiovascular Health study?

SOLUTION: The GPIIIa PlA1/A2 polymorphism is not associated with type 2 diabetes, glucose metabolism, angiographic CHD or myocardial infarction.

PROBLEM: Context: Paris polyphylla is an oriental folk medicine that has anticancer activities both in vivo and in vitro. Polyphyllin VII (PP7), a pennogenyl saponin from P. polyphylla has been found to exert strong anticancer activity. However, the underlying mechanisms are poorly understood. In the present study, the anticancer effect of polyphyllin VII against human liver cancer cells and the molecular mechanisms were investigated.', 'Cellular viability was measured by MTT assay. Apoptosis, intracellular reactive oxygen species (ROS) and mitochondrial membrane potential levels were evaluated using the InCell 2000 confocal microscope. The expression levels of apoptotic-related proteins were evaluated by Western blotting.', 'PP7 strongly inhibited the cell growth and induced apoptosis and necrosis in hepatocellular carcinoma HepG2 cells. Meanwhile, PP7 up-regulated the levels of Bax/Bcl-2, cytochrome c, the cleaved forms of caspases-3, -8, -9, and poly (ADP-ribose) polymerase in a dose- and time-dependent manner, indicating that PP7 induced apoptosis in HepG2 cells through both intrinsic and extrinsic pathways. Moreover, PP7 provoked the production of intracellular ROS and the depolarization of mitochondrial membrane potential. Further analysis showed that PP7 significantly augmented the phosphorylation of JNK, ERK and p38, the major components of mitogen-activated protein kinase (MAPK) pathways, and the expressions of tumor suppressor proteins p53 and PTEN. In addition, PP7-induced apoptosis was remarkably attenuated by MAPK inhibitors and ROS inhibitor.\Question: Does polyphyllin VII induce apoptosis in HepG2 cells through ROS-mediated mitochondrial dysfunction and MAPK pathways?

SOLUTION:
These results demonstrated that PP7 induced apoptotic cell death in HepG2 cells through both intrinsic and extrinsic pathways by promoting the generation of mitochondrial-mediated ROS and activating MAPK and PTEN/p53 pathways.