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: To investigate the impact of prophylactic hyperoxic ventilation with Fio2 0.6 on the physiologic limit of acute normovolemic anemia.', 'Prospective, controlled, randomized experimental study.', 'Experimental animal laboratory of a university hospital.', 'Fourteen anesthetized domestic pigs.', 'Animals were randomly ventilated with either Fio2 0.21 (group 0.21, n = 7) or Fio2 0.6 (group 0.6, n = 7), and acute anemia was induced by isovolemic blood-for-hydroxy-ethylstarch (HES) exchange using a 6% HES solution (130/0.4).', 'The blood-for-HES-exchange was continued until a sudden decrease of total body oxygen consumption indicated the onset of oxygen supply dependency (primary end point); the corresponding hemoglobin (Hb) concentration was defined as "critical" (Hb(crit)). Secondary end points were changes in myocardial function, central hemodynamics, oxygen transport, and tissue oxygenation. Compared with room air ventilation (Fio2 0.21), hyperoxic ventilation with Fio2 0.6 enabled a larger blood-for-HES-exchange (139%, 124/156) of circulating blood volume vs. 87% (68/94, p < .05), until Hb(crit) was reached (1.5 g/dL [1.4/2.1] vs. 2.4 g/dL [2.0/2.8], p < .05). At Hb 2.4 g/dL (i.e., Hb(crit) in group 0.21), animals of group 0.6 still presented with superior oxygen transport, tissue oxygenation, and hemodynamic stability. However, hemodynamic and oxygen transport variables were found deteriorated more severely at Hb 1.5 g/dL (i.e., Hb(crit) of group 0.6) compared with group 0.21 at Hb 2.4 g/dL.\Question: Does hyperoxic ventilation increase the tolerance of acute normovolemic anemia in anesthetized pigs?
[A]: During cell-free volume replacement, hyperoxic ventilation with Fio2 0.6 generates a readily usable plasmatic oxygen reserve and thereby increases the tolerance toward acute normovolemic anemia.


[Q]: Context: Infection of human immunodeficiency virus (HIV) has been associated with several chronic diseases, including pulmonary artery hypertension and atherosclerosis. However, the underlying mechanisms of these vascular complications are largely unknown. The objective of this study was to test a novel hypothesis that HIV Nef, an accessory HIV protein, may directly affect endothelial functions and gene expression in pulmonary arteries.', 'Fresh porcine pulmonary artery rings and human pulmonary artery endothelial cells (HPAECs) were treated with HIV Nef for 24 h. With a myograph device, vasomotor function was determined with thromboxane A2 analog, U46619, for contraction, bradykinin, and sodium nitroprusside for relaxation. The expression of endothelial nitric oxide synthase (eNOS) was determined with real-time PCR and immunohistochemistry. Nitric oxide (NO) production was determined by Calorimetric Nitric Oxide Assay kit. Superoxide anion levels were detected with lucigenin-enhanced chemiluminescence assay and dihydroethidium (DHE) staining.', 'The endothelium-dependent vasorelaxation in response to bradykinin was significantly reduced in HIV Nef-treated porcine pulmonary artery rings in a concentration-dependent manner. In response to bradykinin (10(-8) mol/L), HIV Nef (10 ng/mL) significantly reduced vasorelaxation by 32% compared with untreated controls (P < 0.05). In addition, HIV Nef significantly decreased eNOS expression in the vessels and HPAECs. HIV Nef at 10 ng/mL significantly decreased NO production in HPAECs by 21% compared with controls (P < 0.05). Furthermore, HIV Nef significantly increased superoxide anion production in porcine pulmonary arteries and HPAECs compared with controls (P < 0.05). Consequently, Mn (III) tetrakis porphyrin, a superoxide dismutase mimic, effectively blocked HIV Nef-induced vasomotor dysfunction and superoxide anion production. The specificity of HIV Nef action was confirmed by anti-Nef antibody blocking and Nef heat inactivation.\Question: Does hIV Nef protein cause endothelial dysfunction in porcine pulmonary arteries and human pulmonary artery endothelial cells?
[A]: HIV Nef protein significantly decreases endothelium-dependent vasorelaxation in porcine pulmonary arteries. It also reduces eNOS expression and induces oxidative stress in both porcine pulmonary arteries and HPAECs. This study demonstrates a new mechanism of HIV Nef, which causes endothelial dysfunction and may contribute to the human pulmonary artery disease in HIV-infected patients.


[Q]: Context: It is well known that cyclooxygenase-2 (COX-2) and its major derivative product prostaglandin E2 (PGE2) play key regulatory roles in the ovulation process. Animal studies have demonstrated that the inhibition of nitric oxide (NO) suppresses ovarian PGE2 production and ovulation. Although the expression of NO synthases has been detected in human granulosa cells, the effect of NO on COX-2 expression and PGE2 production in these cells remains unknown.', 'The purpose of this article was to investigate the effects of NO on COX-2 expression and PGE2 production in human granulosa cells.', 'SVOG cells are human granulosa cells that were obtained from women undergoing in vitro fertilization and immortalized with simian virus 40 large T antigen. SVOG cells were used to investigate the effects of NO on COX-2 expression and PGE2 production.', 'The study was conducted in an academic research center.', 'The levels of mRNA and protein were examined by RT-quantitative real-time PCR and Western blotting, respectively. The accumulation levels of PGE2 were measured by ELISA.', 'Treatment with the NO donor S-nitroso-N-acetyl-DL-penicillamine (SNAP) induced COX-2 expression and PGE2 production. In addition, the stimulatory effect of SNAP on COX-2 and PGE2 was mimicked by treatment with the cGMP analog 8-bromo-cGMP (8-Br-cGMP). Interestingly, neither SNAP nor 8-Br-cGMP affected the expression of COX-1. Moreover, our results showed that either SNAP or 8-Br-cGMP activated cAMP response element-binding protein (CREB) signaling and that the knockdown of CREB attenuated SNAP- and 8-Br-cGMP-induced COX-2 expression and PGE2 production.\Question: Do nitric oxide and cGMP induce COX-2 expression and PGE2 production in human granulosa cells through CREB signaling pathway?
[A]:
CREB mediates NO and cGMP-induced COX-2 expression and PGE2 production, which subsequently contribute to NO-regulated ovulation in human granulosa cells.