TASK DEFINITION: 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.
PROBLEM: Tubuloglomerular feedback (TGF) is an important mechanism in control of signal nephron glomerular filtration rate. The oxidative stress in the macula densa, primarily determined by the interactions between nitric oxide (NO) and superoxide (O2-), is essential in maintaining the TGF responsiveness. However, few studies examining the interactions between and amount of NO and O2- generated by the macula densa during normal and hypertensive states.', 'In this study, we used isolated perfused juxtaglomerular apparatus to directly measure the amount and also studied the interactions between NO and O2- in macula densa in both physiological and slow pressor Angiotensin II (Ang II)-induced hypertensive mice.', 'We found that slow pressor Ang II at a dose of 600ng kg(-1) min(-1) for two weeks increased mean arterial pressure by 26.1 5.7mmHg. TGF response increased from 3.40.2m in control to 5.20.2m in hypertensive mice. We first measured O2- generation by the macula densa and found it was undetectable in control mice. However, O2- generation by the macula densa increased to 21.42.5 unit min(-1) in Ang II-induced hypertensive mice. We then measured NO generation and found that NO generation by the macula densa was 138.59.3 unit min(-1) in control mice. The NO was undetectable in the macula densa in hypertensive mice infused with Ang II.

SOLUTION: Does oxidative status in the macula densa modulate tubuloglomerular feedback responsiveness in angiotensin II-induced hypertension?

PROBLEM: Endoscopic snare papillectomy (ESP) is a viable alternative to surgical treatment of ampullary adenomas and T1N0 stage ampullary carcinomas. The main drawback of this technique is the high risk of acute pancreatitis post procedure.The aim of this study was to assess the efficacy, safety, and long-term results of this procedure, and to determine whether routine pancreatic intubation facilitated by intraductal methylene blue (MB) injection reduces the risk for pancreatitis.', 'Between 2004 and 2011, 56 consecutive patients underwent ESP. Before resection, the pancreatic duct was cannulated, and MB was injected intraductally to facilitate stent placement after ampullectomy.', 'ESP was performed en bloc in 45 patients with histological findings of low-grade dysplasia (39%), high-grade dysplasia (25%), carcinoma (32.5%), and others (3.5%). The morbidity rate was 19.5%: acute pancreatitis (n=6), bleeding (n=4), perforation (n=1), and sepsis (n=1). Pancreatic intubation was performed in 89% of the patients. Postprocedure pancreatitis occurred significantly less in the patients with a pancreatic stent than in those without: 3/49 versus 3/6, P=0.013. ESP was considered as curative in 39 patients (75%). Of the 12 recurrences (25%), 10 were managed endoscopically, but with higher morbidity (acute pancreatitis=40%).

SOLUTION: Does pancreatic intubation facilitated by methylene blue injection decrease the risk for postpapillectomy acute pancreatitis?

PROBLEM: We evaluated whether detecting prostate cancer cells by the nested reverse transcriptase-polymerase chain reaction (RT-PCR) in lymph nodes has predictive value for serum prostate specific antigen (PSA) recurrence in patients undergoing radical prostatectomy.', 'We assessed the presence of prostate cancer cells by RT-PCR for prostate specific membrane antigen and PSA assay in lymph nodes dissected from 38 patients with localized prostate cancer treated with radical prostatectomy. The results of nested RT-PCR assay were compared with biochemical recurrence.', 'Nested RT-PCR was positive in the lymph nodes of 2 of 18 patients (11%) with stage pT2a and 5 of 20 (25%) with stage pT2b disease. All 7 patients had biochemical recurrence. We noted a significant difference in the Kaplan-Meier recurrence-free actuarial probability curve in those with positive and negative nested RT-PCR results for prostate specific membrane antigen, PSA and prostate specific membrane antigen-PSA in the lymph nodes (p = 3.02x10(-7), 2.23x10(-7) and 3.02x10(-7), respectively). Multivariate analysis of serum PSA, Gleason score and preoperative RT-PCR assay in peripheral blood showed that nested RT-PCR for prostate specific membrane antigen, PSA and prostate specific membrane antigen-PSA in the lymph nodes were independent predictors of recurrence (p = 0.0089, 0.0075 and 0.0089, respectively).

SOLUTION:
Is detection of micrometastatic prostate cancer cells in the lymph nodes by reverse transcriptase polymerase chain reaction predictive of biochemical recurrence in pathological stage T2 prostate cancer?