An efficient strategy for evaluating new non-invasive screening tests for colorectal cancer: the guiding principles.

OBJECTIVE: New screening tests for colorectal cancer (CRC) are rapidly emerging. Conducting trials with mortality reduction as the end point supporting their adoption is challenging. We re-examined the principles underlying evaluation of new non-invasive tests in view of technological developments and identification of new biomarkers. DESIGN: A formal consensus approach involving a multidisciplinary expert panel revised eight previously established principles. RESULTS: Twelve newly stated principles emerged. Effectiveness of a new test can be evaluated by comparison with a proven comparator non-invasive test. The faecal immunochemical test is now considered the appropriate comparator, while colonoscopy remains the diagnostic standard. For a new test to be able to meet differing screening goals and regulatory requirements, flexibility to adjust its positivity threshold is desirable. A rigorous and efficient four-phased approach is proposed, commencing with small studies assessing the test's ability to discriminate between CRC and non-cancer states (phase I), followed by prospective estimation of accuracy across the continuum of neoplastic lesions in neoplasia-enriched populations (phase II). If these show promise, a provisional test positivity threshold is set before evaluation in typical screening populations. Phase III prospective studies determine single round intention-to-screen programme outcomes and confirm the test positivity threshold. Phase IV studies involve evaluation over repeated screening rounds with monitoring for missed lesions. Phases III and IV findings will provide the real-world data required to model test impact on CRC mortality and incidence. CONCLUSION: New non-invasive tests can be efficiently evaluated by a rigorous phased comparative approach, generating data from unbiased populations that inform predictions of their health impact.

A laboratory challenge model for evaluating enyterocytozoon hepatopenaei susceptibility in selected lines of pacific whiteleg shrimp Penaeus vannamei.

Here we report for the first time a laboratory challenge model for Enterocytozoon hepatopenaei (EHP) to determine the difference of two Specific Pathogen Free (SPF) lines of Penaeus vannamei shrimp. These lines were experimentally challenged using EHP-infected fecal strings as inoculum. Real-time PCR and histopathology assays were performed to confirm EHP infection and evaluate differences in EHP susceptibility in the two genetic lines screened. Although the histopathology of the hepatopancreas tissue showed EHP lesions in both challenged groups, the histological lesions were more pronounced in one of the SPF lines. Quantitative PCR results revealed that animals displaying less hepatocellular damage have lower EHP load compared to animals displaying more pronounced pathological changes. There was no significant difference in final survival at 36 days post-infection in these lines with survival ranging between 80 and 100%. The data showed that mortality as an endpoint metric is not a suitable parameter to determine genetic susceptibility to EHP. Instead, histopathological changes in hepatopancreas, EHP load of the same tissue, and growth retardation would be better metrics to screen EHP susceptibility in P. vannamei. The results show the feasibility of screening genetic lines of P. vannamei for EHP resistance/tolerance using fecal string as an inoculum and, assessing histopathological changes, EHP load, and weight as indicators of resistance.

Detection of a novel microsporidium with intranuclear localization in farmed Penaeus vannamei from Latin America.

Microsporidia are emerging intracellular parasites of most known animal phyla in all ecological niches. In shrimp aquaculture, the microsporidium Enterocytozoon hepatopenaei (EHP) is a major cause of concern inflicting tremendous losses to shrimp producers in southeast Asia. During a histopathological examination of Penaeus vannamei samples originating in a country from Latin America presenting slow growth, we observed abnormal nuclei in the epithelial cells of the hepatopancreas. A PCR screening of the samples using DNA isolated from paraffin embedded tissues for the SSU rRNA gene of EHP provided a 149 bp amplicon. In situ hybridization using the SSU rRNA gene probe provided a positive signal in the nuclei instead of the cytoplasm. Sequence analysis of the SSU rRNA gene product revealed a 91.3 %, 89.2 % and 85.4 % sequence identity to Enterocytozoon bieneusi, E. hepatopenaei and Enterospora canceri respectively. Furthermore, phylogenetic analysis revealed the newly discovered microsporidium clustered with E. bieneusi. Considering the intranuclear location of the novel microsporidium and the differences in the sequence of the SSU rRNA, we tentatively consider this parasite a new member of the genus Enterospora sp. The pathogenicity and distribution of the shrimp Enterospora sp. are currently unknown. Our future efforts are focused on the characterization and development of diagnostic tools for this parasite to understand if it acts as an emergent pathogen that might require surveillance to prevent its spread.

Outlier Vehicle Trajectory Detection Using Deep Autoencoders in Santiago, Chile.

In the last decade, a large amount of data from vehicle location sensors has been generated due to the massification of GPS systems to track them. This is because these sensors usually include multiple variables such as position, speed, angular position of the vehicle, etc., and, furthermore, they are also usually recorded in very short time intervals. On the other hand, routes are often generated so that they do not correspond to reality, due to artifacts such as buildings, bridges, or sensor failures and where, due to the large amount of data, visual analysis of human expert is unable to detect genuinely anomalous routes. The presence of such abnormalities can lead to faulty sensors being detected which may allow sensor replacement to reliably track the vehicle. However, given the reliability of the available sensors, there are very few examples of such anomalies, which can make it difficult to apply supervised learning techniques. In this work we propose the use of unsupervised deep neural network models based on stacked autoencoders to detect anomalous routes in vehicles within Santiago de Chile. The results show that the proposed model is capable of effectively detecting anomalous paths in real data considering validation given by an expert user, reaching a performance of 82.1% on average. As future work, we propose to incorporate the use of Long Short-Term Memory (LSTM) and attention-based networks in order to improve the detection of anomalous trajectories.

Development of a Recombinase Polymerase Amplification (RPA) assay for acute hepatopancreatic necrosis disease (AHPND) detection in Pacific white shrimp (Penaeus vannamei).

Acute hepatopancreatic necrosis disease (AHPND) is currently the most important bacterial disease of shrimp that has caused enormous losses to the shrimp industry worldwide. The causative agent of AHPND are Vibrio spp. Carrying plasmids containing the pirA and pirB genes which encode binary toxins, PirAB. Currently, AHPND is mostly diagnosed by PCR-based platforms which require the use of sophisticated laboratory instrumentation and are not suitable for a point-of-care diagnostics. Therefore, the availability of an alternative method based on isothermal amplification would be suitable for AHPND detection outside a laboratory setting and extremely useful at a pond side location. Isothermal amplification is based on the nucleic acid amplification at a single temperature and does not require the use of a thermal cycler. In this study, we developed an isothermal Recombinase Polymerase Amplification (RPA) assay for AHPND detection targeting both pirA and pirB genes, simultaneously and evaluated the specificity and sensitivity of the assay. The assay could detect AHPND without any cross-reaction with other microbial pathogens and Specific Pathogen Free (SPF) shrimp. The limit of detection of the assay was 5 copies of pirAB genes. To evaluate the reliability of the assay in detecting AHPND, DNA from Penaeus vannamei shrimp displaying acute and chronic infection were analyzed by the RPA assay and the results were compared with SYBR Green real-time PCR assay. While there was a 100% conformity between the two assay while detecting acute phase infection, RPA appeared to be more sensitive in detecting chronic phase infection. The data suggest that RPA assay described here would be a reliable method in detecting AHPND outside a standard laboratory setting.

Photosensitization Induced by Heterophyllaea pustulata in Goats: Sequential Development of Skin Lesions.

Five adult Saanen goats received a single oral dose of Heterophyllaea pustulata containing 42.25 µg/kg rubiadin (anthraquinone) and 3 adult goats were untreated controls. All goats were exposed to sunlight and sequential ear skin biopsies were collected before treatment and at 32 hours, 3 days, 8 days, and 15 days after treatment. Changes at 32 hours after dosing included epidermal spongiosis, single cell death and acantholysis, an increased BAX/BCL-2 protein ratio, and dermal edema. Lesions at day 3 included epidermal and adnexal necrosis, crust formation, and acanthosis. Acanthosis, hyperkeratosis, and dermal fibrosis and neovascularization were present at day 15. The pro-apoptotic (BAX)/anti-apoptotic (BCL-2) protein ratio increased at 32 hours, whereas epidermal and dermal PCNA immunolabeling increased between days 8 and 15 after treatment. The cutaneous lesions were consistent with sunlight-induced damage, and the occurrence in treated but not control goats indicates photosensitization.

Co-Training for Visual Object Recognition Based on Self-Supervised Models Using a Cross-Entropy Regularization.

Automatic recognition of visual objects using a deep learning approach has been successfully applied to multiple areas. However, deep learning techniques require a large amount of labeled data, which is usually expensive to obtain. An alternative is to use semi-supervised models, such as co-training, where multiple complementary views are combined using a small amount of labeled data. A simple way to associate views to visual objects is through the application of a degree of rotation or a type of filter. In this work, we propose a co-training model for visual object recognition using deep neural networks by adding layers of self-supervised neural networks as intermediate inputs to the views, where the views are diversified through the cross-entropy regularization of their outputs. Since the model merges the concepts of co-training and self-supervised learning by considering the differentiation of outputs, we called it Differential Self-Supervised Co-Training (DSSCo-Training). This paper presents some experiments using the DSSCo-Training model to well-known image datasets such as MNIST, CIFAR-100, and SVHN. The results indicate that the proposed model is competitive with the state-of-art models and shows an average relative improvement of 5% in accuracy for several datasets, despite its greater simplicity with respect to more recent approaches.

Acute hepatopancreatic necrosis disease (VPAHPND), a chronic disease in shrimp (Penaeus vannamei) population raised in latin America.

In Latin American shrimp farming, acute hepatopancreatic necrosis disease (AHPND) does not cause the acute mortalities observed in SE Asia. Herein we report for the first time a new phase of infection of AHPND, a chronic phase based on two experimental AHPND-challenge trials using shrimp lines from Latin America. Three shrimp lines of Penaeus vannamei were challenged with a highly pathogenic strain of Vibrio parahaemolyticus causing AHPND (VPAHPND). PCR and histopathology assays were used for confirmation of AHPND in the trials. The first study was to compare survival between the lines. A follow-up trial was conducted to document hepatopancreas heterotrophic bacterial count and to measure the expression of VPAHPND binary toxin genes (pirAB genes) at 24 h.p.i. One of the Latin American shrimp lines, APE1, had significantly higher survival than recorded for the other two lines (APE2 & APE3) and the specific-pathogen-free positive control line. Histopathology showed typical AHPND acute and terminal phase lesions in VPAHPND challenged groups, although destructive cellular changes were more pronounced in the SPF line. Histopathology of animals surviving AHPND revealed a unique chronic phase of infection that resembles septic hepatopancreatic necrosis (SHPN), recognized as diagnostic of digestive tract vibriosis. Data to support our finding, including a quantitative RT-PCR assay, confirmed the expression of pirAB genes and the differential hepatopancreas heterotrophic plate count (HPC) among the different lines challenged. The results explain in part why the shrimp industry in some Latin American countries continues to grow despite the presence of AHPND. In addition, the biology and pathology of AHPND resistant/tolerant shrimp appear to be quite unique in this Latin American shrimp population.

A comparative study of Enterocytozoon hepatopenaei (EHP) challenge methods in Penaeus vannamei.

The microsporidium Enterocytozoon hepatopenaei (EHP) is considered as an emerging pathogen threating the shrimp industry worldwide. It is an intracellular parasite that has been associated with retarded growth syndrome and white feces syndrome in shrimp. Although the impact of EHP to the shrimp industry is well known, many aspects of host-pathogen interactions are not well understood. A major limitation in the study of EHP is the lack of a reliable method to produce large quantities of inoculum rapidly and reproducibly. The present study was designed to compare different challenge methods including intramuscular injection, oral administration, co-habitation, hepatopancreas (HP) injection and reverse gavage. The results showed that the HP injection and the reverse gavage are two promising methods to infect shrimp rapidly and generate inoculum in a reproducible manner starting with a limited amount of inoculum. Therefore, the HP injection and reverse gavage were chosen for a scale-up study. Histopathology results showed that EHP proliferated in the epithelial cells of the HP in shrimp challenged via direct injection of inoculum into HP and reverse gavage treatments. In accordance with the histopathology results, the qPCR data showed that EHP loads in the challenged shrimp increased significantly with the HP injection and reverse gavage methods. Furthermore, the histopathological and quantification results indicate that HP injection and reverse gavage are two novel methods that can be used in EHP-challenge studies and for rapidly generating viable EHP inoculum.

Evidences supporting Enterocytozoon hepatopenaei association with white feces syndrome in farmed Penaeus vannamei in Venezuela and Indonesia.

White feces syndrome (WFS) is an emerging and poorly described disease characterized by the presence of floating white fecal strings in shrimp (Penaeus monodon and P. vannamei) grow-out ponds. WFS has been associated with several pathogens, including Enterocytozoon hepatopenaei. This association is based on the fact that in areas where E. hepatopenaei has been reported, there was also a high WFS prevalence. E. hepatopenaei is an emerging pathogen that has affected cultured shrimp in Indonesia, Vietnam, China, Thailand, and India. In 2016, we reported the presence of E. hepatopenaei in farmed P. vannamei in Venezuela. In this study, we describe the first case of WFS in Venezuela associated with E. hepatopenaei. The white fecal strings and shrimp displaying white feces along the gastrointestinal tract observed in this study were similar to the gross signs found in WFS-impacted P. vannamei in SE Asian countries. Furthermore, we describe a strong association between WFS and E. hepatopenaei in the samples obtained from Venezuela and Indonesia. Quantification of E. hepatopenaei in WFS-affected ponds, ponds with a history of WFS, and ponds with no WFS showed that E. hepatopenaei loads were significantly higher in WFS-affected ponds. Furthermore, these findings constitute the first report of WFS being associated with E. hepatopenaei in farmed shrimp in Latin America. Additionally, we propose that the gross signs of WFS such as floating whitish fecal strings can be used as an indicator of the presence of E. hepatopenaei in countries where E. hepatopenaei is endemic.

Assessment of transmission risk in WSSV-infected shrimp Litopenaeus vannamei upon cooking.

White spot syndrome virus has been a threat to the global shrimp industry since it was discovered in Taiwan in 1992. Thus, shrimp-producing countries have launched regulations to prevent import of WSSV-infected commodity shrimp from endemic areas. Recently, cooked shrimp that is infected with WSSV tested positive by PCR. However, there is no study to determine the infectivity of WSSV in cooked shrimp that tested positive by PCR. In the present study, WSSV-infected shrimp were cooked at boiling temperature for different times including 0, 1, 3, 5, 10 and 30 min. Upon exposure to boiling temperature, WSSV-infected shrimp were fed to SPF shrimp (Litopenaeus vannamei). The result showed experimentally challenged shrimp from 0-min treatment (positive control) indeed got infected with WSSV. However, experimentally challenged shrimp that were fed tissues boiled at 1, 3, 5, 10 and 30 min were not infected with WSSV. Mortality data showed that only the positive control (0-min) treatment displayed high mortality, whereas no mortality was observed in any other treatment category. These findings suggest that cooking shrimp at boiling temperature for at least 1 min might prevent any potential spread of WSSV from endemic countries to other geographical areas where WSSV has not yet been reported.

Novel infectious myonecrosis virus (IMNV) genotypes associated with disease outbreaks on Penaeus vannamei shrimp farms in Indonesia.

Infectious myonecrosis virus (IMNV) is one of the most pathogenic viruses that affect Penaeus vannamei shrimp. In 2018, IMNV was reported in grow-out ponds of P. vannamei in Situbondo, Indonesia. Diseased animals displayed clinical signs of infectious myonecrosis (IMN) characterized by white discoloration of skeletal muscle. Histopathology of affected shrimp revealed lesions that are pathognomonic of IMNV infection. The major capsid protein (MCP) gene was amplified and sequenced from representative samples showing IMN pathology. Multiple alignment of predicted amino acid sequences of the MCP gene with known IMNV genotypes in the GenBank database revealed three unique genotypes, SB-A, SB-B and SB-C,in Situbondo samples. The number of amino acid changes in SB-A, SB-B and SB-C compared to known IMNV genotypes ranged from 7-710, including the isolate SB-B, which contains deletion of 622 aa. A phylogenetic analysis using homologous sequences from Brazil and Indonesia showed that these three isolates represent new IMNV genotypes.

First report of acute hepatopancreatic necrosis disease (AHPND) occurring in the USA.

In June 2017, mass mortalities were reported at whiteleg shrimp Penaeus vannamei farms in Texas, USA. PCR testing for OIE-listed and non-listed pathogens detected the pirA and pirB toxin genes associated with acute hepatopancreatic necrosis disease (AHPND). DNA sequence analyses of cloned pirA and pirB genes showed them to be identical to those detected in other AHPND-causing Vibrio sp. Amplicons generated using PCR tests targeted to the toxR gene showed the Pir toxin genes to be associated with a V. parahaemolyticus type more similar to a genotype found in Mexico compared to that found in Asia. Histology detected masses of bacteria and hemocytic infiltrations as well as extensive necrosis and sloughing of epithelial cells in hepatopancreatic tubules pathognomonic of AHPND. The data support AHPND as the cause of the mortalities. Given that US companies produce shrimp broodstock for farms in Asia and Latin America, the further spread of AHPND in the USA needs to be prevented to avoid serious economic consequences to these industries.

Mixture of Experts with Entropic Regularization for Data Classification.

Today, there is growing interest in the automatic classification of a variety of tasks, such as weather forecasting, product recommendations, intrusion detection, and people recognition. "Mixture-of-experts" is a well-known classification technique; it is a probabilistic model consisting of local expert classifiers weighted by a gate network that is typically based on softmax functions, combined with learnable complex patterns in data. In this scheme, one data point is influenced by only one expert; as a result, the training process can be misguided in real datasets for which complex data need to be explained by multiple experts. In this work, we propose a variant of the regular mixture-of-experts model. In the proposed model, the cost classification is penalized by the Shannon entropy of the gating network in order to avoid a "winner-takes-all" output for the gating network. Experiments show the advantage of our approach using several real datasets, with improvements in mean accuracy of 3-6% in some datasets. In future work, we plan to embed feature selection into this model.

Barrett's esophagus after Roux-en-Y gastric bypass: does regression occur?

INTRODUCTION: Barrett's esophagus (BE) is recognized as a premalignant lesion for esophageal adenocarcinoma. BE appears as a consequence of gastroesophageal reflux disease (GERD), which is increased among obese population. Laparoscopic Roux-en-Y gastric bypass (LRYGB) is the best treatment option for obesity combined with GERD. However, data on evolution of BE after LRYGB are scarce. METHODS AND PROCEDURES: Patients were studied with esophagogastroduodenoscopy (EGD) and gastric biopsy preoperatively. If BE was suspected, esophageal biopsy was performed. If BE was confirmed, LRYGB was indicated with yearly surveillance EGD with biopsies. LRYGB patients who had BE with at least 1-year follow-up were included. RESULTS: Between 10/07 and 1/16, 2144 patients underwent laparoscopic bariatric surgery at our institution. There were 1681 (78 %) LRYGB, 399 (19 %) laparoscopic sleeve gastrectomies, and 64 (3 %) revisions. Nineteen patients (0.9 %) had BE preoperatively, and they all underwent LRYGB; 11 of them (58 %) were eligible for this study. There were 6 women and 5 men, mean age 49 ± 11 years, initial BMI 44 ± 6 kg/m2. Mean follow-up was 41 ± 31 months; there were 9 short-segment BE (SSBE) and 2 long-segment BE (LSBE). On pre- and post-op EGD, BE length was 2.1 ± 1.6 and 1.2 ± 1.2 cm, respectively (p = NS). Post-op EGD was compatible with BE in all cases, although esophageal biopsy showed remission in 4 (36 %) cases: three short-segment BE (SSBE) and one long-segment BE (LSBE). One patient was indefinite for dysplasia and remained the same after the operation. CONCLUSION: Our preliminary data showed that LRYGB is a suitable treatment option for obese patients with BE, demonstrated by 36 % regression rate of this premalignant disease. Although BE persisted in the remaining patients, no progression to dysplasia was observed. A larger number of patients and longer follow-up are needed for more definitive conclusions.

Does laparoscopic sleeve gastrectomy have any influence on gastroesophageal reflux disease? Preliminary results.

INTRODUCTION: There is no question that Roux-en-Y gastric bypass (RYGB) is the best treatment option for obesity combined with GERD. However, the influence of laparoscopic sleeve gastrectomy (LSG) on this disease remains controversial. It has been said that LSG could induce de novo GERD or worsen it. The aim of our study was to evaluate the influence of LSG on GERD. METHODS AND PROCEDURES: Candidates for LSG underwent esophageal manometry (EM) and 24 h pH monitoring before and 1 year after LSG. Symptoms were evaluated using a validated score. Esophageal function test (EFT's) results and symptoms were compared before and after surgery. RESULTS: Between 4/12 and 9/13, 118 patients underwent LSG. EFT's were performed in 92 (78%) of them preoperatively. From the 19 patients 1 year out of surgery, 14 (73%) completed their EFT's postop. There were 13 women, age 42 ± 12 years, BMI 40 ± 6 kg/m(2). At 14 months, % excess weight loss (EWL) was 74. EM: lower esophageal sphincter (LES) length increased from 2.7 to 3.2 cm (p = NS), and LES pressure decreased from 17.1 to 12.4 mmHg (p ≤ 0.05). Preoperatively, LES was normotensive in 13 (93%) patients; postoperatively, LES was normal in 10 (71%) (p = NS). DeMeester score increased from 12.6 to 28.4 (p ≤ 0.05). Postoperatively, 5 (36%) patients had de novo GERD, in 3 (21%) GERD worsened, 1 (7%) remained with GERD and 5 (36%) remained without reflux. No difference was seen between preop. and postop. symptoms score. CONCLUSION: Our preliminary data showed that after LSG LESP significantly decreased, and the DeMeester score significantly increased. Although LSG results appear appealing in terms of weight loss, patients should be warned that they might need proton pump inhibitors after the operation. Surgeons should probably lower their threshold for indicating RYGB in patients with known preoperative GERD.

Management of early-stage esophageal neoplasia (MESEN) consensus.

BACKGROUND: Treatment of esophageal adenocarcinoma often involves surgical resection. Newer technologies in interventional endoscopy have led to a substantial paradigm shift in the management of early-stage neoplasia in Barrett's esophagus comprising high-grade dysplasia (HGD), intramucosal carcinoma, and, in some cases, submucosal carcinoma. However, there has been no consensus regarding the indications for esophageal preservation in these cases. In this work, consensus guidelines were established for the management of early-stage esophageal neoplasia considering clinically relevant aspects (age, comorbidities, and social environment) in each scenario. METHODS: Seventeen experts were invited to participate based on their background and clinical expertise at high-volume centers. A questionnaire was created that included four clinical scenarios covering a wide range of situations within HGD and/or early esophageal neoplasia, particularly where controversies are likely to exist. Each of the clinical scenarios was open to discussion subdivided by patient age (20, 50, and 80 s). For each clinical scenario an expert was chosen to defend that position. Each defense triggered a subsequent discussion during a consensus meeting. Conclusions of that discussion together with an accompanying literature analysis allowed experts to confirm or change their original choices and served as the basis for the recommendations stated in this article. RESULTS: There was 100 % consensus supporting esophageal preservation in patients with HGD, independent of patient age or Barrett's length. In patients with T1a adenocarcinoma, consensus for preservation was not reached (65 %) for young and middle-aged individuals but was supported for elderly patients (100 %). For T1b adenocarcinoma, consensus was reached for surgical resection (90 %), leaving organ preservation for patients with very low risk of nodal invasion or poor surgical candidates. CONCLUSION: Advances in endoscopic imaging and therapy allow for organ preservation in most settings of early-stage neoplasia of the esophagus, provided that the patient understands the implications of this decision.

[Detection of polyps, adenomas, advanced adenomas and adenocarcinomas in patients between 45 and 49 years]. / Detección de pólipos, adenomas, adenomas avanzados y adenocarcinomas de colon en pacientes entre 45 y 49 años.

UNLABELLED: BACKGROUND. Colorectal cancer (CRC) can be prevented. Colonoscopy is the first-line procedure for screening in average risk population. In 2002, Imperiale evaluated people between 40 to 49 years and reported that adenomas and advanced adenomas presented in 8.5% and 3.5% of cases, respectively. Currently, no recommendations for CRC screening in this population have been made. OBJECTIVE: To estimate the prevalence ofpolyps, adenomas, advanced lesions and adenocarcinomas in the 45- to 49-year-old population. METHODS: We included consecutive adults between 45 and 49 years old who performed colonoscopy because of gastrointestinal signs or symptoms. Exclusion criteria were high risk for CRC, incomplete VCC and/or previous evidence of colonic lesions. The study was conducted in a gastroenterology center from Buenos Aires, between September 2010 and October 2011. The design was prospective and cross-sectional. Polyethylene glycol (PEG) lavage solution or phosphates were usedfor cleansing. Colonoscopies were performed under sedation with Olympus equipment. The protocol was approved by the local IRB. 95% confidence intervals (95% CI) were estimated. RESULTS: 814 patients were evaluated and 764 were included, 440 (57%) were women and the average age was 47 years. The global prevalence of polyps was 20% (160 cases, 95% CI 18%-24%). The global prevalence of adenomas was 14% (107 cases, 95% CI 11%-16%). The prevalence of advanced adenomas was 5% (39 cases, 95% CI 4%-7%) and the prevalence of adenocarcinoma was 0.1% (1 case, 95% CI 0%-0.7%). CONCLUSIONS: The prevalence of lesions in this population is lower than that in the average risk population. At the moment we do understand that there is no evidence to recommend CRC screening in 45- to 49-year-old individuals.

[Contributions of endoscopic ultrasound to pancreatic cystic lesions]. / Aportes de la ecografía endoscópica a las lesiones quísticas del páncreas.

Cystic lesions of the pancreas are peculiar in relation to their diagnosis and treatment. The use of endoscopic ultrasonography (EUS) has provided better sensitivity and specificity to differentiate benign from malignant cysts, condition that provides an early diagnosis and an effective and definite treatment.

[Prevalence of rectosigmoid adenomas and adenocarcinomas in patients younger than 50 years old referred for proctorrhagia]. / Prevalencia de adenomas y adenocarcinomas de recto-sigma en pacientes menores de 50 años que consultan por proctorragia.

BACKGROUND: Rectal bleeding is a sign of colorectal cancer (CRC). Its early diagnosis decreases mortality and improves survival. In young population with no risk factors for the disease, CRC is infrequent. Moreover, benign anorectal disorders are most frequent causes of bleeding and generally, when anal pathology is identified, it is assumed as the origin of the sign. For all these reasons, rectal bleeding sometimes is sub-assessed in young patients. OBJECTIVE: Estimate the prevalence of adenomas and adenocarcinomas in sigmoid and rectum in patients younger than 50 years old referred for proctorrhagia. METHODS: The study design was descriptive, retrospective and cross-sectional. Procedures were performed under sedation and Olympus CF 160 y CF 180 scopes were used. Proctorrhagia was considered as rectal bleeding registered as indication of the procedure. Histology was established according to Vienna classification. Informed consent was signed before the procedures. Colonoscopy reports were reviewed. The study took place in an outpatient clinic in Buenos Aires city, between October 2010 and October 2011. High risk patients for CRC were excluded RESULTS: We included 1,203 from 1,257 reviewed VCC, 49% were female and the median age was 38 years old (range: 18-49 years old). The prevalence of adenomas and adenocarcinomas in sigmoid and rectum was 67% [95% confidence interval (95% CI): 5.4-8.3] and 1.6% (95% CI 1-2.5), respectively. CONCLUSIONS: Adenocarcinomas and adenomas are infrequent in a young population without risk factors for CRC. However, even when benign anal disorders are the most frequent cause for rectal bleeding, miss evaluation of this sign could have a serious impact in almost 10 of 100 individuals.