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.

Context: Blood oxygen level-dependent (BOLD) MRI has been effectively used to monitor changes in renal oxygenation. However, R2* (or T2*) is not specific to blood oxygenation and is dependent on other factors. This study investigates the use of a statistical model that takes these factors into account and maps BOLD MRI measurements to blood pO2.', "Spin echo and gradient echo images were obtained in six Sprague-Dawley rats and R2 and R2* maps were computed. Measurements were made at baseline, post-nitric oxide synthase inhibitor (L-NAME), and post-furosemide administration. A simulation of each region was performed to map R2' (computed as R2*-R2) to blood pO2.", 'At baseline, blood pO2 in the outer medulla was 30.5\u2009±\u20091.2 mmHg and 51.9\u2009±\u20095.2 mmHg in the cortex, in agreement with previous invasive studies. Blood pO2 was found to decrease within the outer medulla following L-NAME (P\u2009<\u20090.05) and increase after furosemide (P\u2009<\u20090.05). Blood pO2 in the cortex increased following furosemide (P\u2009<\u20090.05).
Answer: Model-derived blood pO2 is sensitive to pharmacological challenges, and baseline pO2 is comparable to literature values. Reporting pO2 instead of R2* could lead to a greater clinical impact of renal BOLD MRI and facilitate the identification of hypoxic regions. Magn Reson Med, 2016. © 2016 International Society for Magnetic Resonance in Medicine.
Is bOLD quantified renal pO2 sensitive to pharmacological challenges in rats?

Context: Biliary tract obstruction is a common clinical problem. In this study, we attempted to understand the change in intestinal glucose absorption after biliary tract obstruction.', 'Experimental models of murine biliary duct ligation and external biliary drainage were established. Murine intestinal mucosal glucose absorption was examined with Ussing chambers according to the increase in the short-circuit current in\xa0vitro and blood glucose measurement after oral glucose in\xa0vivo. The protein expression of the sodium-glucose cotransporter (SGLT1) and the facilitated glucose transporter, member 2 (GLUT2) was analyzed by Western blot and immunohistochemistry.', 'The results from Ussing chamber experiments showed that duodenal mucosal glucose absorption levels were significantly higher in biliary duct ligation and biliary drainage mice than those in normal control mice at 1 and 2\xa0weeks after the operation. Gastrointestinal bile acid administration almost reversed the elevated duodenal mucosal glucose absorption to the normal level in biliary drainage mice. The results from the experiments in\xa0vivo further confirmed that the glucose absorption increased in biliary duct ligation and biliary drainage mice. The protein expression levels of SGLT1 in the duodenal mucosae of both biliary duct ligation and biliary drainage mice were markedly higher than those in control mice, and the protein expression of GLUT2 was not significantly altered, compared with control mice.
Answer: Bile deficiency in the intestine upregulates the expression of intestinal mucosal SGLT1 and enhances intestinal mucosal glucose absorption capacity, which contributes to the understanding of intestinal physiologic function for patients with biliary duct obstruction and external biliary drainage.
Does bile deficiency induce changes in intestinal glucose absorption in mice?

Context: The aim of this study was to analyze the biochemical and histochemical effects of radiation therapy and protective melatonin administration on periodontal tissues in rats with experimental periodontitis.', 'Sixty male Sprague Dawley rats were divided into six groups, as follows: control; experimental periodontitis (Ped); radiotherapy administration (Rt); experimental periodontitis and exposure to irradiation (Ped-Rt); radiotherapy and protective melatonin administration (Rt-Mel); and periodontitis, radiation therapy and protective melatonin administration (Ped-Rt-Mel). The rats were killed at the end of the experimental procedure, and the oxidative stress level and periodontal destruction were compared among the groups.', "The oxidative stress index and the levels of 8-hydroxy-2'-deoxyguanosine, malondialdehyde and C-terminal telopeptide of type I collagen were found to be significantly higher in the Ped-Rt group compared with the Ped group (p < 0.05), and the levels were lower in the Ped-Rt-Mel group than in the Ped-Rt group (p < 0.05). Alveolar bone destruction and attachment level were also significantly lower in the Ped-Rt-Mel group than in the Ped-Rt group (p < 0.05).
Answer: It was found that radiotherapy increased oxidative stress, the periodontal attachment level and alveolar bone loss, and protective melatonin administration significantly reduced the oxidative parameters and prevented periodontal damage in irradiated rats with experimental periodontitis. Further research is needed regarding the use of systemic melatonin administration before radiation therapy.

Does melatonin prevent radiation-induced oxidative stress and periodontal tissue breakdown in irradiated rats with experimental periodontitis?