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.

[Q]: Context: It is well established that African Americans (AA) experience greater pain associated with a variety of clinical conditions, and greater pain sensitivity to experimental pain tasks relative to non-Hispanic Whites (W). Notably, African Americans do not show the same relationships involving endogenous pain regulatory mechanisms and pain sensitivity documented in Caucasians, including positive associations between blood pressure, norepinephrine, cortisol and greater pain tolerance.', 'The purpose of this study was to examine the relationship between plasma oxytocin (OT) and pain sensitivity and to explore the relation of OT to other factors known to influence pain perception.', 'OT concentration and sensitivity to ischemic, cold pressor, and thermal pain tasks were assessed in African American (n=25) and non-Hispanic White (n=23) pre-menopausal women.', 'African American women demonstrated significantly lower pain tolerance across tasks compared with Whites (F(1,46)=6.31, p=0.0156) and also exhibited lower plasma OT levels (AA: 3.90, W: 7.05 pg/mL; p=0.0014). Greater OT levels were correlated with greater tolerance to ischemic pain (r=0.36, p=0.013) and accounted for a marginally significant portion of the ethnic difference in ischemic pain tolerance (B=+0.29, p=0.06). Greater OT was also correlated with greater tolerance of cold pressor pain (r=0.31, p=0.03); however, this association was no longer seen after the variance due to ethnicity was accounted for.
Answer: These data suggest that reduced oxytocinergic function may be one of multiple biological factors contributing to the greater sensitivity to experimental ischemic pain, and to the greater burden of some types of clinical pain experienced by African Americans compared with Whites.
[A]: Is ethnicity associated with alterations in oxytocin relationships to pain sensitivity in women?

[Q]: Context: The fruits of Vitex rotundifolia L. are widely used to treat inflammation of the airway in Traditional Chinese medicine. Previous studies found that casticin, isolated from Vitex rotundifolia, could induce apoptosis of tumor cells. In this study, we evaluated the anti-inflammatory effects of casticin and its underlying molecular mechanism in lipopolysaccharide (LPS)-stimulated macrophages.', 'RAW264.7 cells were pretreated with various concentrations of casticin (0.3-10M), and then treated with LPS to induce inflammation. We assayed the levels of proinflammatory cytokines and prostaglandin E2 (PGE2) using ELISA, and examined the protein expression of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, and heme oxygenase (HO)-1 by Western blot. We also investigated the anti-inflammatory molecular mechanism by analyzing inflammatory-associated signaling pathways, including the nuclear transcription factor kappa-B (NF-B) and mitogen-activated protein kinase (MAPK) pathways.', 'We found casticin inhibited the levels of nitric oxide and PGE2, and decreased the production of proinflammatory cytokines such as interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF-). In addition, iNOS and COX-2 expression levels were suppressed and casticin increased HO-1 and Nrf2 production in a concentration-dependent manner. Furthermore, casticin significantly inhibited NF-B subunit p65 proteins in the nucleus and decreased Akt and MAPK activation.
Answer: These results suggest that the anti-inflammatory effect of casticin is due to inhibition of proinflammatory cytokines and mediators by blocking the NF-B, Akt, and MAPK signaling pathways.
[A]: Does casticin inhibit COX-2 and iNOS expression via suppression of NF-B and MAPK signaling in lipopolysaccharide-stimulated mouse macrophages?

[Q]: Context: The objective of the study was to investigate the splanchnic blood flow velocity and oximetry response to blood transfusion in preterm infants according to postnatal age.', 'Preterm infants receiving blood transfusion were recruited to three groups: 1-7 (group 1; n = 20), 8-28 (group 2; n = 21) and 29 days of life (group 3; n = 18). Superior mesenteric artery (SMA) peak systolic (PSV) and diastolic velocities were measured 30-60 min pre- and post-transfusion using Doppler ultrasound scan. Splanchnic tissue haemoglobin index (sTHI), tissue oxygenation index (sTOI) and fractional tissue oxygen extraction (sFTOE) were measured from 15-20 min before to post-transfusion using near-infrared spectroscopy.', 'The mean pretransfusion Hb in group 1, 2 and 3 was 11, 10 and 9 g/dl, respectively. The mean (SD) pretransfusion SMA PSV in group 1, 2 and 3 was 063 (032), 081 (033) and 097 (040) m/s, respectively, and this did not change significantly following transfusion. The mean (SD) pretransfusion sTOI in group 1, 2 and 3 was 367 (193), 446 (104) and 413 (104)%, respectively. The sTHI and sTOI increased (P < 001), and sFTOE decreased (P < 001) following transfusion in all groups. On multivariate analysis, changes in SMA PSV and sTOI following blood transfusion were not associated with PDA, feeding, pretransfusion Hb and mean blood pressure.
Answer: Pretransfusion baseline splanchnic tissue oximetry and blood flow velocity varied with postnatal age. Blood transfusion improved intestinal tissue oxygenation without altering mesenteric blood flow velocity irrespective of postnatal ages.
[A]:
Does blood transfusion in preterm infants improve intestinal tissue oxygenation without alteration in blood flow?