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.

[EX Q]: Context: 99mTc-HMPAO is a well-established isotope useful in the detection of regional cerebral blood flow. Diabetes gives rise to arterial atherosclerotic changes that can lead to significant end organ dysfunction, prominently affecting perfusion to the heart, kidneys, eyes and brain. In the current study, we investigated the role of 99mTc-HMPAO cerebral perfusion scans in detecting early vascular changes in the diabetic brain.', 'Cerebral perfusion studies were performed on both control and streptozotocin-(STZ) induced diabetic male Wistar rats. Rat brain imaging using a gamma camera was performed for each group 0.5, 2, 4, and 24 hours post 99mTc-HMPAO injection. Data processing for each cerebral perfusion scan was performed by drawing a region of interest (ROI) circumferentially around the brain (B). Background (BKG) due to signal from the soft tissue of each rat was subtracted. Brain 99mTc-HMPAO uptake minus background counts (net brain counts; NBC) were then compared between the two groups.', 'The NBC (mean +/- SD) for the STZ group were statistically significantly higher (p = 0.0004) than those of the control group at each of the time points studied.
Answer: 99mTc-HMPAO brain scan may be useful in the detection of early atherosclerotic changes in the diabetic rat brain.
[EX A]: Does perfusion scanning using 99mTc-HMPAO detect early cerebrovascular changes in the diabetic rat?

[EX Q]: Context: Evidence of hyperplasia with atypia found both on random periareolar fine needle aspiration (RPFNA) and in nipple aspirate fluid (NAF) fluid are associated with an increased risk for breast cancer.', 'In this study, we report the correlation of NAF production with cytological assessment of ductal cells obtained by RPFNA.', '113 women at high risk for development of breast cancer attending the Breast Cancer Prevention Clinic at the University of Kansas Medical Center underwent a single NAF collection attempt and RPFNA.', 'NAF was successfully collected in 51% of women. There was no significant difference in age, 5-year Gail risk assessment, menopausal status, hormone use, family history of breast cancer, history of prior atypical hyperplasia/LCIS or history of contralateral DCIS/invasive breast cancer between women who produced NAF and those that did not. The only significant difference between the two groups was in history of prior lactation (p = 0.018). Twenty-seven of the 113 subjects were found to have hyperplasia with atypia by RPFNA was 31% in women who produced NAF versus 16% in those who did not (p = 0.07).
Answer: Although prevalence of RPFNA atypia was numerically higher in NAF producers than non-producers the difference did not reach statistical significance. Failure to produce NAF does not exclude the presence of hyperplasia with atypia by random periareolar fine needle aspiration.
[EX A]: Does failure of high risk women to produce nipple aspirate fluid exclude detection of cytologic atypia in random periareolar fine needle aspiration specimens?

[EX Q]: Context: To investigate the effect of rhein on endothelial plasminogen activator inhibitor-1 (PAI-1) mRNA expression and protein production induced by transforming growth factor beta1 (TGFbeta1), and to explore the mechanism of the protective action of rhein on endothelial cells.', 'A human umbilical endothelium derived cell line (ECV-304) from ATCC was used in this study. The PAI-1 mRNA expression and protein synthesis in the endothelial cells were detected by Northern blot and flow cytometry analysis, respectively. The activity of phospho-p44/p42 MAP kinase induced by TGFbeta1 was determined by immunoprecipitation analysis and western blot.', 'TGFbeta1 rapidly increased PAI-1 mRNA expression in the endothelial cells, and this effect lasted at least 24 hours. The upregulation of PAI-1 mRNA expression induced by TGFbeta1 in endothelial cells was inhibited by rhein in a dose-dependent manner. In addition, rhein inhibited endothelial PAI-1 protein production. Further study revealed that rhein had a significant inhibitory effect on the activity of phospho-p44/p42 MAP kinase induced by TGFbeta1 in human endothelial cells.
Answer: Our results showed that rhein may have a protective effect on the endothelial dysfunction by inhibiting overexpression of PAI-1, indicating a way for the treatment of vascular diseases.
[EX A]:
Does rhein inhibit transforming growth factor beta1 induced plasminogen activator inhibitor-1 in endothelial cells?