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.

Input: Consider Input: To determine whether the number and location of positive surgical margins (PSMs) in radical prostatectomy (RP) surgical specimens affect biochemical recurrence (BCR) rates.', 'The locations of PSMs were recorded for 1308 consecutive men who underwent RP between October 2000 and December 2006. BCR was defined as three consecutive prostate-specific antigen (PSA) level rises with the peak level >or=0.15 ng/mL. Multivariate regression analyses were used to identify preoperative predictors of PSMs and BCR. The estimated 5-year risk of BCR was calculated using the Kaplan-Meier method.', 'In all, 128 (9.8%) men had one or more PSMs. The mean body mass index, mean preoperative serum PSA level, the distributions of clinical stage and biopsy Gleason scores, and the presence or absence of biopsy perineural invasion were significantly different between men with or with no PSMs. In multivariate analysis, baseline serum PSA level, Gleason score and perineural invasion were independent preoperative predictors of PSMs. The 5-year actuarial BCR rates were dependent on the site of the PSM (P = 0.035) and not the number of PSMs (P = 0.18). The rank order of estimated 5-year BCR rates according to the site of PSMs were base > anterior > posterolateral > apex approximately posterior.

Output: Does site of positive surgical margins influence biochemical recurrence after radical prostatectomy?

Input: Consider Input: The clinical significance of the hepatitis B virus core-related antigen (HBcrAg) assay in monitoring the antiviral effects of lamivudine is reviewed.', 'The HBcrAg assay simultaneously measured serum levels of hepatitis B core (HBc) and e (HBe) antigens using monoclonal antibodies which recognize common epitopes of these two denatured antigens.', 'Although serum HBcrAg levels correlated linearly with those of hepatitis B virus (HBV) DNA in natural course, the decrease in HBcrAg was significantly slower than in HBV DNA after initiation of lamivudine administration. We analyzed the clinical significance of HBV DNA and HBcrAg levels to predict the occurrence of lamivudine resistance. HBV DNA measurement may be useful to identify patients who are at high risk of developing lamivudine resistance, and HBcrAg measurement may help to detect patients who are at low risk of drug resistance. The measurement of HBcrAg was also found to be a useful prognosticator for reactivation of hepatitis after cessation of lamivudine administration.

Output: Is hepatitis B core-related antigen assay useful for monitoring the antiviral effects of nucleoside analogue therapy?

Input: Consider Input: Because of the immunomodulatory effects of transfusion, we attempted to identify factors associated with blood product use and determine the association of transfusion quantity with postoperative infection.', 'We studied total perioperative transfusion of blood products for 15,592 cardiovascular operations performed from July 1998 to May 2003. Infection end points were septicemia/bacteremia (n=351, 2.2%) and superficial (n=353, 2.3%) and deep (n=212, 1.4%) sternal wound infections. Factors associated with blood product administration were used to form balancing scores to adjust for differences in patient characteristics among those receiving and not receiving blood products.', 'Fifty-five percent of patients received packed red blood cells (RBC), 21% received platelets, 13% got fresh frozen plasma (FFP), and 3% got cryoprecipitate. Factors associated with RBC use included older age, female gender, higher New York Heart Association class, lower hematocrit, reoperation, and longer cardiopulmonary bypass time--all indicative of higher-risk patients. The more RBC units transfused, the higher was the occurrence of septicemia/bacteremia (p < 0.0001) and superficial (p=0.0007) and deep (p < 0.0001) sternal wound infection. Use of FFP (septicemia/bacteremia) and platelets (septicemia/bacteremia and deep sternal wound infection) mitigated against this association only slightly.
Output: Does transfusion increase the risk of postoperative infection after cardiovascular surgery?