Dataset Information

Assessing Effect of Withdrawal Time on Adenoma Detection Rate for Screening Colonoscopy

ABSTRACT: The investigators’ null hypothesis is that a withdrawal time of 9 to 10 minutes is non-inferior to a withdrawal time of 12 minutes or greater. Thus, the goal of this tandem design trial is to compare the additional diagnostic yield (# of missed lesions) for withdrawal times exceeding 10 minutes for screening/surveillance colonoscopies. Although withdrawal times longer than the standard 6-minute recommendation have been shown to be beneficial, there is limited prospective evidence investigating the benefit or lack thereof for withdrawal times greater than 9-10 minutes.

DISEASE(S): Colon Cancer,Colorectal Cancer,Rectal Cancer,Adenoma

PROVIDER: 2387643 | ecrin-mdr-crc |

REPOSITORIES: ECRIN MDR

ACCESS DATA

Shared Molecules

Only show the datasets with similarity scores above: 0.5

Threshold

0.5

Similar Datasets

Project description:Kindling induced by Pentylenetetrazol is an established rodent model of epileptogenesis. The molecular basis of the long-term plasticity involved is however not clear. In addition, rodent models of kindling plasticity are not useful for large-scale screening of compounds to identify antiepileptogenic drugs. Given this, we have developed a fly model of chronic PTZ- and withdrawal-induced behavioral plasticity. In our fly model, the chronic PTZ treatment is given for 7 days. This is then followed by 7 day long withdrawal. Expression profiling of fly heads at three time points in the 7 day long withdrawal period – 8th day, 10th day, and 14th day from the beginning of the treatment - showed a dynamic and widespread alteration of various functional categories of genes. D. melanogaster Oregon-R wild type cultures were grown at 24 + 1oC, 60% RH, and 12 hrs light (9 AM to 9 PM) and 12 hours dark cycle. Three to four days old adult males, unmated, were grown in either normal food (NF) or food containing 8 mg/ml of PTZ for seven days. Following this, the control and PTZ treated individuals were shifted to vials containing NF and maintained further for seven days. Each vial contained 30 individuals in the beginning of the treatment. Heads were harvested at three time points during withdrawal - 8th day, 10th day, and 14th day from the beginning of the treatment. Heads of flies frozen in liquid nitrogen were collected, after vigorous shaking of the vial containing the flies, using cooled sieves. Total RNA was isolated from eight pools of frozen heads, every two of which represented a single parallel set of treatment in which four vials contained NF treated control flies, and four PTZ exposed individuals, during treatment or withdrawal period. For isolation, TRI REAGENT (Sigma) was used as per manufacturer’s recommendation. Double stranded cDNA was synthesized from 10 µg of total RNA using Microarray cDNA Synthesis Kit (Roche). The cDNA was purified using Micorarray Target Purification Kit (Roche), according to the manufacturer’s protocol. Each of the four sets of control and treated cDNA samples, belonging to the four biological replicates, was used for labeling with either Cy3 or Cy5 dyes (Amersham Biosciences) using Microarray RNA Target Synthesis Kit T7 (Roche). The labeled products were purified by Microarray Target Purification Kit (Roche). The Cy3 and Cy5 labeled two cRNA samples of each biological replicate were pooled together, precipitated, washed, air-dried, and dissolved in 18MΩ RNAase free water (Sigma). Dye swapping was accomplished by hybridizing two arrays with NF control as Cy3- and PTZ treated as Cy5- labeled sample, and the rest two as the opposite, NF as Cy5- and drug treated as Cy3- labeled sample. The labeled product was mixed with hybridization solution containing hybridization buffer (DIG Easy Hyb; Roche), 10mg/ml salmon testis DNA (0.05 mg/ml final concentration, Sigma) and 10mg/ml yeast tRNA (0.05 mg/ml final concentration, Sigma). The hybridization mixture was denatured at 65ºC and applied onto cDNA microarray slides (D12Kv1, CDMC, Toronto). The slides were covered by a coverslip (ESCO, Portsmouth, USA) and hybridization was allowed to take place in hybridization chamber (Corning) at 37ºC for 16 hrs. Following hybridization, the coverslips were removed in a solution containing 1X SSC and 0.1% SDS at 50ºC, and the slides washed in 1X SSC and 0.1% SDS (three times for 15 minutes each) in a coplin jar at 50ºC with occasional swirling and then transferred to 1X SSC and washed with gentle swirling at room temperature (twice for 15 minutes each). Slides were given a final wash in 0.1X SSC for 15 minutes and then liquid was quickly removed from the slide surface by spinning at 600 rpm for 5 minutes. Slides were scanned at 10µm resolution in GenePix 4000A Microarray Scanner (Molecular Devices). The preprocessing and quantification of the 16 bit TIFF images were carried out using Gene Pix Pro 6.0 software (Molecular Devices). Ratio based normalization was performed using Acuity 4.0 software (Molecular Devices). All Spots with raw intensity less then 100U and less then twice the average background was ignored during normalization. Normalized data was filtered for the selection of features before further analysis. Only those spot were selected which contained only a small percentage (<3) of saturated pixels, were not flagged bad or found absent (flags >= 0), had relatively uniform intensity and uniform background (Rgn R2 (635/532) >= 0.6) and were detectable above background (SNR >= 3). Analyzable spots in at least three of the four biological replicates performed were retrieved for downstream analysis using Significance Analysis of Microarrays (SAM 2.21, Excel Add-In, Stanford) under the conditions of one class response and 100 permutations.