Subjects in the FIT group were more likely to participate in screening than were those in the colonoscopy group. On the baseline screening examination, the numbers of subjects in whom colorectal cancer was detected were similar in the two study groups, but more adenomas were identified in the colonoscopy group. (Funded by Instituto de Salud Carlos III and others; ClinicalTrials.gov number, NCT00906997.).

Gut microbiota is the most complex bacterial community in the human body and its study may give important clues to the etiology of different intestinal diseases. Most studies carried out so far have used fecal samples, assuming that these samples have a similar distribution to the communities present throughout the colon. The present study was designed to test this assumption by comparing samples from the rectal mucosa and feces of nine healthy volunteers by sequencing libraries of 16S rRNA genes. At the family taxonomic level, where rarefaction curves indicate that the observed number of taxa is close to the expected one, we observe under different statistical analyses that fecal and mucosal samples cluster separately. The same is found at the level of species considering phylogenetic information. Consequently, it cannot be stated that both samples from a given individual are of similar composition. We believe that the evidence in support of this statement is strong and that it would not change by increasing the number of individuals and/or performing massive sequencing. We do not expect clinicians to stop using feces for research, but we think it is important to caution them on their potential lack of representativeness with respect to the bacterial biofilm on the rectal mucosa.

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During nine years, 157 consecutive patients with achalasia have been dilated in our unit. First, the long-term effect of dilation on clinical status was evaluated. The probability of being in clinical remission eight years after first dilation was 51%. The pressure of the LES measured after dilation was highly predictive of the long-term clinical evolution. Second, a predictive model of the individual response to pneumatic dilation was developed and simplified. Therapy was effective in 80% of the patients, after one to four dilations. Younger age was the only factor significantly associated with ineffective therapy. Depending on the prognosis of the outcome calculated with the predictive model, patients were classified in groups of risk that showed a different rate of ineffective, therapy. In the simplified model, age < or = 20 years, male gender, esophageal body diameter < or = 3 cm, esophageal body basal pressure > 15 mm Hg, and pressure of the lower esophageal sphincter > 30 mm Hg were predictors of a poor response to dilation. We conclude that pneumatic dilation is an effective therapy for achalasia. A predictive model was useful to classify the patients in groups with a different risk for ineffective dilation. A simplification of this model could be used to predict the response to dilation.