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.

The aim of this study was to develop an assay system that can quantify the amount of biomass in biofilms formed by different isogenic mutants of an Escherichia coli K-12 strain.', 'The reported assay, which is based on the BacTiter-Glo assay from Promega, uses bioluminescence to detect the intracellular concentration of ATP, which correlates with viable bacterial cell numbers. The quantitative data obtained with this ATP assay were compared to those obtained with the conventional crystal violet assay. As a qualitative control, scanning electron microscopy was performed.
Does a combination of assays reveal biomass differences in biofilms formed by Escherichia coli mutants?

Results from GOG 178 showed a prolongation of progression-free survival (PFS) with the immediate use of chemotherapy (CT) following a complete clinical response (CR) in patients with stage III-IV ovarian cancer. We wanted to evaluate our strategy of reserving second line (2nd line) chemotherapy to the time of clinical recurrence by determining PFS intervals following first, second, and third line agents and to compare these finding to results of GOG 178.', 'We conducted a retrospective parallel study to GOG 178 using identical criteria for PFS definitions. Patients (pts) with stage III-IV cancer achieving a CR following surgery and five to eight cycles of platinum-based CT were identified. Patients not obtaining a CR and those with a CR who underwent second look surgery were excluded. Rather than immediately beginning consolidation CT after CR, second line agents were started at recurrence and were followed by a third line when pts progressed. Clinical-pathologic characteristics were abstracted, and time intervals including time to recurrence, time to use of second line CT, time to use of third line (3rd line) CT, and survival were recorded. Time intervals were studied by Kaplan-Meier method.', 'Of 217 reviewed pts (1991-2001), 59 eligible pts were identified. Forty-nine patients had stage III disease and ten had stage IV. At completion of surgery, 44 were optimally debulked. With a median follow-up of 51 months, the median PFS (from CR) of all patients was 20 months. At 5 years, 36% of pts remain disease-free, and 66% of pts are alive. Twenty-three pts have not received second line agents, and thirty-six have received them. For all pts, the median time from CR to start of second line chemotherapy was 21 months, and the median time to start of third line agents was 43 months. Recurrences occurred after 6 months from completion of first line (1st line) therapy in 87% of cases and after 12 months in 50%.
Is timing n't everything : an analysis of when to start salvage chemotherapy in ovarian cancer?

The expression of tight junction-related transmembrane protein claudin-7 (CLDN7) and its regulatory mechanism were investigated in colorectal carcinomas (CRCs).', "Methylation-specific polymerase chain reaction and treatment with the demethylating agent 5-aza-2'-deoxycytidine were conducted to analyze the methylation status at the CLDN7 promoter region in the Colo320 CRC cell line. We used a total of 26 stage 0 CRCs with an adenoma component and 90 invasive CRCs (stage I-IV), as well as their corresponding lymph node metastases, in an immunohistochemical study.", "In Colo320 (CLDN7-negative) cells, hypermethylation at the CLDN7 promoter was detected and treatment with 5-aza-2'-deoxycytidine restored CLDN7 expression. In CRC tissues, decreased CLDN7 expression was detected in 62% of stage 0 CRCs and 80% of stage I-IV CRCs, compared with their adjacent adenoma lesions and nonneoplastic epithelia, which had a close correlation with the incidence of vessel infiltration and clinicopathologic stage. Hypermethylation at the CLDN7 promoter was detected in 20% of CRCs with low CLDN7 expression. However, CLDN7 expression tended to be re-expressed in their corresponding lymph node metastases.

Does hypermethylation-modulated downregulation of claudin-7 expression promote the progression of colorectal carcinoma?