TASK DEFINITION: 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.
PROBLEM: Context: Completeness of cytoreduction is a significant predictor of long-term outcome after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Imaging has limited sensitivity to identify peritoneal metastases and therefore predict whether complete cytoreduction is possible. We reviewed our experience using laparoscopy to determine candidates for complete cytoreduction and HIPEC.', 'This single-center, retrospective study examined patients from 2007 to 2014 who underwent laparoscopy to determine complete cytoreduction (CC-0/1)/HIPEC candidacy. Preoperative, intraoperative, and postoperative data were collected.', 'A total of 145 laparoscopies were performed on 141 patients, 72 (51.1\xa0%) of whom were female, with a median age of 53\xa0years (range 20-79). The primary site was appendiceal in 67 (47.5\xa0%) patients, colorectal in 43 (30.5\xa0%), mesothelioma in 17 (12.1\xa0%), unknown in 9 (6.4\xa0%), small bowel in 3 (2.1\xa0%), gastric in 1, and ovarian in 1 (0.7\xa0% each). Overall, 115 (81.6\xa0%) patients had prior abdominal surgery, 111 (76.6\xa0%) had evidence of disease on imaging, and 117 (80.7\xa0%) underwent prior chemotherapy, with a median of 5.9\xa0weeks between the last treatment and laparoscopy (0.9-498.9\xa0weeks). Four (2.8\xa0%) intraoperative complications were observed (one liver laceration, two enterotomies, and one air embolus), and nine (6.2\xa0%) postoperative complications [four (2.8\xa0%) Clavien grade (CG) I, three (2.8\xa0%) CG II, one (0.7\xa0%) CG III (return to operating room) and one (0.7\xa0%) CG IV (transient ischemic attack)]. Forty-eight patients deemed candidates by laparoscopy underwent CRS/HIPEC (positive predictive value 82.8\xa0%).
Answer: Diagnostic laparoscopy is a safe, feasible, and accurate staging tool in patients with suspected peritoneal metastases being considered for CRS.

SOLUTION: Is laparoscopy Safe and Accurate to Evaluate Peritoneal Surface Metastasis Prior to Cytoreductive Surgery?

PROBLEM: Context: Aneurysm shrinkage has been proposed as a marker of successful endovascular aneurysm repair (EVAR). Patients with early postoperative shrinkage may experience fewer subsequent complications, and consequently require less intensive surveillance.', 'Patients undergoing EVAR from 2000 to 2011 at three vascular centres (in 2 countries), who had two imaging examinations (postoperative and after 6-18 months), were included. Maximum diameter, complications and secondary interventions during follow-up were registered. Patients were categorized according to early sac dynamics. The primary endpoint was freedom from late complications. Secondary endpoints were freedom from secondary intervention, postimplant rupture and direct (type I/III) endoleaks.', 'Some 597 EVARs (71.1 per cent of all EVARs) were included. No shrinkage was observed in 284 patients (47.6 per cent), moderate shrinkage (5-9 mm) in 142 (23.8 per cent) and major shrinkage (at least 10 mm) in 171 patients (28.6 per cent). Four years after the index imaging, the rate of freedom from complications was 84.3 (95 per cent confidence interval 78.7 to 89.8), 88.1 (80.6 to 95.5) and 94.4 (90.1 to 98.7) per cent respectively. No shrinkage was an independent risk factor for late complications compared with major shrinkage (hazard ratio (HR) 3.11; P < 0.001). Moderate compared with major shrinkage (HR 2.10; P = 0.022), early postoperative complications (HR 3.34; P < 0.001) and increasing abdominal aortic aneurysm baseline diameter (HR 1.02; P = 0.001) were also risk factors for late complications. Freedom from secondary interventions and direct endoleaks was greater for patients with major sac shrinkage.
Answer: Early change in aneurysm sac diameter is a strong predictor of late complications after EVAR. Patients with major sac shrinkage have a very low risk of complications for up to 5 years. This parameter may be used to tailor postoperative surveillance.

SOLUTION: Does early sac shrinkage predict a low risk of late complications after endovascular aortic aneurysm repair?

PROBLEM: Context: Bacterial translocation through the gastrointestinal tract is the crucial step in the pathogenesis of intraabdominal infections. We assessed whether aggregation substance (AS), a bacterial adhesin and virulence factor of Enterococcus faecalis, promotes bacterial translocation and colonic mucosal invasion in an ex vivo experiment.', "Colonic mucosa of male Wistar rats was placed in a modified Ussing system. The mucosal side of the chamber was filled with a suspension of E. faecalis OG1X:pAM721 (AS-positive) or E. faecalis OG1X (AS-negative). The serosal side was filled with sterile Dulbecco's modified Eagle's medium. For assessment of colonic mucosal invasion the mucosal side was incubated for 2.5 h with a suspension of AS-positive or AS-negative enterococci. After being washed, a solution of gentamicin and penicillin G in tissue culture medium was added on both sides in order to kill extracellular bacteria. Subsequently, the mucosa was removed from the system, washed, lysed with Triton X-100, and homogenized. Viable intramural bacteria were quantified by plating serial dilutions of the homogenate on Todd-Hewitt broth agar plates. To quantify bacterial translocation samples which were taken at various time points from the serosal side were plated on Todd-Hewitt broth agar plates and colony forming units (CFU) were determined.", 'Invasion of the AS-positive E. faecalis strain OG1X:pAM721 into the colonic mucosa was significantly higher than invasion rates of the AS-negative strain OG1X (2.88 log(10) CFU/ml vs 1.73 log(10) CFU/ml; P = 0.02). However, none of the tested strains was found to translocate from the mucosal to the serosal side within the incubation time of 4 h.
Answer: The aggregation substance promotes invasion of E. faecalis into colonic mucosa.

SOLUTION:
Does aggregation substance promote colonic mucosal invasion of Enterococcus faecalis in an ex vivo model?