instruction:
Given a passage, 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.
question:
The vascular endothelial growth factor (VEGF) family and VEGF receptors (VEGFR) play an essential role in the angiogenesis of both pathologic and nonpathologic conditions. However, the prognostic significance of VEGF and VEGFR expression in ovarian carcinoma is unclear.', 'The tissue expression levels of VEGF-A, VEGF-C, VEGFR-2, and VEGFR-3 in 80 specimens of ovarian carcinoma were examined immnohistochemically. The results obtained were analyzed clinicopathologically.', 'VEGF-A, VEGF-C, VEGFR-2, and VEGFR-3 were expressed both in tumor cells and in adjacent endothelial cells of blood and lymph vessels. The tissue expressions of VEGF-C and VEGFR-2 were correlated significantly with tumor extension, including peritoneal metastases outside the pelvic cavity (P = 0.0010 and P = 0.0008, respectively), lymph node metastases (P = 0.0030 and P = 0.0018, respectively), and positive ascitic cytology (P = 0.025 and P = 0.0016, respectively). Conversely, there was no significant correlation between VEGF-A and VEGFR-3 expression and clinicopathologic features of ovarian carcinoma. Logistic regression analysis revealed that the expressions of VEGF-C and VEGFR-2 also were independent risk factors for peritoneal and lymph node metastases. Survival curves determined by the Kaplan-Meier method and in univariate analysis demonstrated that high expression levels of VEGF-C and VEGFR-2 were associated with the 5-year survival rate. In multivariate analysis, high expression levels of VEGF-C and VEGFR-2 emerged as independent indicators for disease-specific survival.
answer:
Are vascular endothelial growth factor C and vascular endothelial growth factor receptor 2 related closely to the prognosis of patients with ovarian carcinoma?


question:
To determine microRNA (miRNA) expression in human blastocysts relative to advanced maternal age and chromosome constitution.', "Cryopreserved human blastocysts were warmed and underwent a trophectoderm biopsy for comprehensive chromosomal screening. Select blastocysts were then lysed, reverse transcribed, and pre-amplified prior to running real-time PCR. Statistical analysis was performed using an internal constant housekeeping miRNA. Significant microRNA's of interest were then analyzed for their predicted genes and biological pathways. Additional cryopreserved blastocysts were warmed and stained for the SIRT1 protein for validation.", 'Human blastocysts exhibit unique miRNA expression profiles in relation to maternal age and chromosome constitution. miR-93 was exclusively expressed in blastocysts from women in their forties and further up-regulated with an abnormal chromosome complement. Up-regulated miR-93 resulted in an inverse down-regulation of targets like SIRT1, resulting in reduced oxidative defense.
answer:
Do human blastocysts exhibit unique microrna profiles in relation to maternal age and chromosome constitution?


question:
To compare the safety and success of a retrograde approach using a microcatheter vs. a sheath in the treatment of superficial femoral artery (SFA) chronic total occlusions (CTOs).', 'From April 2007 to December 2012, 188 consecutive patients underwent EVT for 229 de novo SFA CTOs using the retrograde approach in 68 patients (35 men; mean age 72 years). This cohort was divided into cases performed with a 4-F or 6-F sheath (n=28, 36 limbs) and those with a 2.1-F microcatheter (n=35, 49 limbs). The primary outcomes were mean time to hemostasis and number of intra- and postoperative puncture site complications, as well as the success of popliteal artery puncture, lesion crossing, and reperfusion.', 'There were no significant differences between two groups in baseline characteristics. PA puncture was successful in all limbs, and the success in crossing the lesion with the wire was not significantly different (91.9% in the sheath group vs. 89.8% in the microcatheter group). Mean time to hemostasis was 8.9±8.8 minutes in the microcatheter group vs. 47.7±13 minutes in the sheath group (p<0.0001). There was a significant difference in intraoperative and postoperative complications (22.2% in the sheath group vs. 2.0% in the microcatheter group, p=0.002).
answer:

Is a sheathless retrograde approach via the popliteal artery useful and safe for treating chronic total occlusions in the superficial femoral artery?