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.

Q: Ductal carcinoma in situ with microinvasion (DCISM) is a rare diagnosis with a good prognosis. Although nodal metastases are uncommon, sentinel lymph node biopsy (SLNB) remains standard care. Volume of disease in invasive breast cancer is associated with SLNB positivity, and, thus we hypothesized that in a large cohort of patients with DCISM, multiple foci of microinvasion might be associated with a higher risk of positive SLNB.', 'Records from a prospective institutional database were reviewed to identify patients with DCISM who underwent SLNB between June 1997 and December 2010. Pathology reports were reviewed for number of microinvasive foci and categorized as 1 focus or ≥2 foci. Demographic, pathologic, treatment, and outcome data were obtained and analyzed.', 'Of 414 patients, 235 (57 %) had 1 focus of microinvasion and 179 (43 %) had ≥2 foci. SLNB macrometastases were found in 1.4 %, and micrometastases were found in 6.3 %; neither were significantly different between patients with 1 focus versus ≥2 foci (p = 1.0). Patients with positive SLNB or ≥2 foci of microinvasion were more likely to receive chemotherapy. At median 4.9 years (range 0-16.2 years) follow-up, 18 patients, all in the SLNB negative group, had recurred for an overall 5-year recurrence-free proportion of 95.9 %.

A: Is extent of microinvasion in ductal carcinoma in situ associated with sentinel lymph node metastases?
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Q: To investigate the effect of kappa-Opioid receptors in the cardioprotection elicited by ischemic postconditioning and the underlying mechanism.', 'The isolated perfused hearts of male Sprague-Dawley rats were subjected to 30 min of global ischemia followed by 120 min of reperfusion. formazan content of myocardium was measured spectrophotometrically, and the level of lactate dehydrogenase (LDH) in the coronary effluent was also measured. In isolated ventricular myocytes hypoxia postconditioning was achieved by 3 cycles of 5 min reoxygenation/5 min hypoxia starting at the beginning of reoxygenation, and cell viability was measured.', 'In the Langendorff perfused rat heart model, ischemic postconditioning (6 cycles of 10 s reperfusion/10 s global ischemia starting at the beginning of reperfusion) increased formazan content, reduced LDH release, improved the recovery of the left ventricular developed pressure, maximal rise/fall rate of left ventricular pressure, left ventricular end-diastolic pressure and rate pressure product (left ventricular developed pressure multiplied by heart rate), attenuated the decrease of coronary flow during reperfusion and increased the isolated cell viability. Pretreatment with nor-BNI, an antagonist of kappa-Opioid receptors and mitoK(ATP) blocker 5-HD attenuated the effect of ischemic/hypoxic postconditioning.

A: Does [ Kappa-opioid receptor mediate the cardioprotective effect of ischemic postconditioning ]?
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Q: Currently there is no reliable medical treatment for aortic regurgitation (AR).', 'Thirty-nine Sprague-Dawley rats underwent creation of AR or sham operation. Treated rats were assigned to early or late institution of sildenafil therapy (100\xa0mg/kg/day) for a total of 10\xa0weeks. Treatment-effects were measured by serial echocardiography, invasive hemodynamic measurements, and tissue analysis.', 'Rats assigned to early treatment developed less remodeling than untreated rats. Thus, left ventricular (LV) dilation was blunted by sildenafil with end-systolic diameter being significantly smaller (6.6\xa0±\xa00.4 vs. 7.7\xa0±\xa00.4\xa0mm, respectively, p\xa0<\xa00.05). Also, LV wall thickness was significantly decreased in treated rats compared to controls (2.23\xa0±\xa00.08 vs. 2.16\xa0±\xa00.05\xa0mm, p\xa0<\xa00.01). Fractional shortening was improved by treatment (p\xa0<\xa00.05). Myocardial fibrosis was borderline decreased by treatment (p\xa0=\xa00.09). Akt was increased in treated compared to controls (p\xa0<\xa00.05).

A:
Does sildenafil treatment attenuate ventricular remodeling in an experimental model of aortic regurgitation?
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