Mário Dinis-Ribeiro

University of Porto, Oporto, Porto, Portugal

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Publications (158)612.41 Total impact

  • Farhan Riaz · Ali Hassan · Rida Nisar · Mario Dinis-Ribeiro · Miguel Coimbra ·
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    ABSTRACT: The design of computer assisted decision (CAD) systems for different biomedical imaging scenarios is a challenging task in computer vision. Sometimes, this challenge can be attributed to the image acquisition mechanisms since the lack of control on the cameras can create different visualizations of the same imaging site under different rotation, scaling and illumination parameters, with a requirement to get a consistent diagnosis by the CAD systems. Moreover, the images acquired from different sites have specific colors, making the use of standard color spaces highly redundant. In this paper, we propose to tackle these issues by introducing novel region based texture, and color descriptors. The proposed tetxure features are based on the usage of analytic Gabor filters (for compensation of illumination variations) followed by the calculation of first and second order statics of the filter responses and making them invariant using some trivial mathematical operators. The proposed color features are obtained by compensating for the illumination variations in the images using homomorphic filtering followed by a bag-ofwords approach to obtain the most typical colors in the images. The proposed features are used for the identification of cancer in images from two distinct imaging modalities i.e., gastroenterology and dermoscopy. Experiments demonstrate that the proposed descriptors compares favorably to several other state-of-the-art methods, elucidating on the effectiveness of adapted features for image characterization.
    10/2015; DOI:10.1109/JBHI.2015.2492464
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    ABSTRACT: Objective: Early diagnosis of gastric cancer may be achieved through surveillance of patients with extensive gastric intestinal metaplasia (eGIM). However, diagnosis of eGIM generally implies histology. We aimed at determining the accuracy of high-resolution endoscopy with light-narrow band imaging (NBI) to assess the presence of eGIM on a per-patient basis. Material and methods: Prospective cohort of 60 patients divided into two groups: derivation cohort (n = 25) to evaluate the reliability and validity, and a real-time validation group (n = 35). In the derivation group, six endoscopists with two levels of expertise were asked to estimate the grade of GIM based in endoscopic images (white light endoscopy, light-NBI and amplification/near focus). In the real-time validation set, experienced endoscopists were asked to similarly record their real-time optical diagnosis. Histology was then considered as the gold standard. Results: In the derivation group diagnosis accuracy was 60% with WLE (non-expert 59% vs. 61% experts), increasing to 73% after NBI magnification (non-expert 63% vs. 83% expert, p < 0.05). Moreover, proportion of agreement with histology was 83%, with a correct diagnosis of eGIM in 87% for experienced observers. In the real-time group experts obtained 89% global diagnostic accuracy correctly identifying 91% of the eGIM. The sensitivity, specificity, LR + and LR- of real-time endoscopic diagnosis of eGIM was 0.92 (CI95%:0.67-0.99), 0.96 (0.79-0.99), 21.1 (3.08-144) and 0.09 (0.013-0.57). Conclusion: For the first time the reliability of high-resolution endoscopy with light-NBI for extension of GIM is described. Our results suggest that more than 90% of individuals at risk could be identified without the need for biopsies, simplifying the current recommendations.
    Scandinavian Journal of Gastroenterology 10/2015; DOI:10.3109/00365521.2015.1101779 · 2.36 Impact Factor
  • Diogo Libânio · Mário Dinis-Ribeiro · Pedro Pimentel-Nunes ·
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    ABSTRACT: The accepted paradigm for intestinal-type gastric cancer pathogenesis is a multistep progression from chronic gastritis induced by Helicobacter pylori (H. pylori) to gastric atrophy, intestinal metaplasia, dysplasia and ultimately gastric cancer. The genetic and molecular mechanisms underlying disease progression are still not completely understood as only a fraction of colonized individuals ever develop neoplasia suggesting that bacterial, host and environmental factors are involved. MicroRNAs are noncoding RNAs that may influence H. pylori-related pathology through the regulation of the transcription and expression of various genes, playing an important role in inflammation, cell proliferation, apoptosis and differentiation. Indeed, H. pylori have been shown to modify microRNA expression in the gastric mucosa and microRNAs are involved in the immune host response to the bacteria and in the regulation of the inflammatory response. MicroRNAs have a key role in the regulation of inflammatory pathways and H. pylori may influence inflammation-mediated gastric carcinogenesis possibly through DNA methylation and epigenetic silencing of tumor suppressor microRNAs. Furthermore, microRNAs influenced by H. pylori also have been found to be involved in cell cycle regulation, apoptosis and epithelial-mesenchymal transition. Altogether, microRNAs seem to have an important role in the progression from gastritis to preneoplastic conditions and neoplastic lesions and since each microRNA can control the expression of hundreds to thousands of genes, knowledge of microRNAs target genes and their functions are of paramount importance. In this article we present a comprehensive review about the role of microRNAs in H. pylori gastric carcinogenesis, identifying the microRNAs downregulated and upregulated in the infection and clarifying their biological role in the link between immune host response, inflammation, DNA methylation and gastric carcinogenesis.
    10/2015; 6(5):111-32. DOI:10.5306/wjco.v6.i5.111
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    Alexandre Ferreira · Joana Moleiro · Joana Torres · Mario Dinis-Ribeiro ·

    10/2015; DOI:10.1055/s-0034-1393079
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    ABSTRACT: This Guideline is an official statement of the European Society of Gastrointestinal Endoscopy (ESGE). It addresses the diagnosis and management of nonvariceal upper gastrointestinal hemorrhage (NVUGIH).
    Endoscopy 10/2015; 47(10):a1-a46. DOI:10.1055/s-0034-1393172 · 5.05 Impact Factor
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    ABSTRACT: Heterogeneity at the Helicobacter pylori cagA gene promoter region has been linked to variation in CagA expression and gastric histopathology. Here, we characterized the cagA promoter and expression in 46 H. pylori strains from Portugal. Our results confirm the relationship between cagA promoter region variation and protein expression originally observed in strains from Colombia. We observed that individuals with intestinal metaplasia were all infected with H. pylori strains containing a specific cagA motif. Additionally, we provided novel functional evidence that strain-specific sequences in the cagA promoter region and CagA expression levels influence interleukin-8 secretion by the host gastric epithelial cells.
    The Journal of Infectious Diseases 09/2015; DOI:10.1093/infdis/jiv467 · 6.00 Impact Factor
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    ABSTRACT: This Guideline is an official statement of the European Society of Gastrointestinal Endoscopy (ESGE). The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system 1 2 was adopted to define the strength of recommendations and the quality of evidence. Main recommendations 1 ESGE recommends endoscopic en bloc resection for superficial esophageal squamous cell cancers (SCCs), excluding those with obvious submucosal involvement (strong recommendation, moderate quality evidence). Endoscopic mucosal resection (EMR) may be considered in such lesions when they are smaller than 10 mm if en bloc resection can be assured. However, ESGE recommends endoscopic submucosal dissection (ESD) as the first option, mainly to provide an en bloc resection with accurate pathology staging and to avoid missing important histological features (strong recommendation, moderate quality evidence). 2 ESGE recommends endoscopic resection with a curative intent for visible lesions in Barrett's esophagus (strong recommendation, moderate quality evidence). ESD has not been shown to be superior to EMR for excision of mucosal cancer, and for that reason EMR should be preferred. ESD may be considered in selected cases, such as lesions larger than 15 mm, poorly lifting tumors, and lesions at risk for submucosal invasion (strong recommendation, moderate quality evidence). 3 ESGE recommends endoscopic resection for the treatment of gastric superficial neoplastic lesions that possess a very low risk of lymph node metastasis (strong recommendation, high quality evidence). EMR is an acceptable option for lesions smaller than 10 - 15 mm with a very low probability of advanced histology (Paris 0-IIa). However, ESGE recommends ESD as treatment of choice for most gastric superficial neoplastic lesions (strong recommendation, moderate quality evidence). 4 ESGE states that the majority of colonic and rectal superficial lesions can be effectively removed in a curative way by standard polypectomy and/or by EMR (strong recommendation, moderate quality evidence). ESD can be considered for removal of colonic and rectal lesions with high suspicion of limited submucosal invasion that is based on two main criteria of depressed morphology and irregular or nongranular surface pattern, particularly if the lesions are larger than 20 mm; or ESD can be considered for colorectal lesions that otherwise cannot be optimally and radically removed by snare-based techniques (strong recommendation, moderate quality evidence). © Georg Thieme Verlag KG Stuttgart · New York.
    Endoscopy 09/2015; 47(9):829-854. DOI:10.1055/s-0034-1392882 · 5.05 Impact Factor
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    Pedro Pimentel-Nunes · Mário Dinis-Ribeiro ·

    09/2015; 22(5):184-186. DOI:10.1016/j.jpge.2015.08.002
  • Mariana Costa · Diogo Libânio · Jorge Lage · Mário Dinis-Ribeiro · Pedro Pimentel-Nunes ·

    Gastrointestinal endoscopy 07/2015; DOI:10.1016/j.gie.2015.07.030 · 5.37 Impact Factor
  • Pedro C Figueiredo · Pedro Pimentel-Nunes · Diogo Libânio · Mário Dinis-Ribeiro ·
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    ABSTRACT: Endoscopic resection is a standard treatment for gastric superficial lesions. A positive or a nonevaluable margin is considered a noncurative criterion. We aimed to systematically review recurrence, residual disease, lymph node metastasis (LNM) and cancer-related death following Rx/R1 resection of gastric lesions in the absence of other noncurative criteria. MEDLINE systematic review and meta-analysis by July 2014. Data were extracted from 31 manuscripts. Definitions and results differed significantly. However, nonevaluable (HMx) and positive horizontal margins (HM1) were associated with 10% [95% confidence interval (CI) 5-15%] and 36% (95% CI 24-48%) rates of recurrence/residual disease, respectively, with an odds ratio of 2.85 (95% CI 1.6-5.8, P<0.01) for HM1 compared with HMx. Nonevaluable (VMx) or positive (VM1) vertical margin was associated with a 43% (95% CI 17-68%) rate of recurrence/residual. VMx/VM1 was associated with a higher risk of recurrence/residual compared with HMx/HM1 (odds ratio 3.76, 95% CI 1.71-6.82, P<0.01). The most common strategy after HMx/HM1 was endoscopic surveillance and retreatment, whereas surgery was recommended after VMx/VM1. No cases of LNM or cancer-related death were noticeable if neither submucosal invasion more than 500 µm nor lymphovascular infiltration was also reported. Rx/R1 resection in the absence of other noncurative criteria does not appear to be a significant risk factor for LNM or cancer-related death. The risk of recurrence/residual disease is higher after HM1 than HMx and higher after VMx/VM1 than HMx/HM1. However, considerable heterogeneity was found in studies. Standard definitions should be created and applied in future studies.
    European journal of gastroenterology & hepatology 07/2015; 27(11). DOI:10.1097/MEG.0000000000000440 · 2.25 Impact Factor
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    ABSTRACT: The presence of lymph node (LN) metastasis is a key prognostic factor for gastric adenocarcinoma. However, even among patients without LN metastasis (N0), recurrence may occur. In some of these cases, occult tumor cells (OTC) are thought to play an important role. We aimed to determine the prevalence of OTC and its clinical relevance. We conducted a systematic review of studies in English published until September 2013 that addressed OTC prevalence and/or its clinical relevance. The studies were retrieved from the MEDLINE database. We included 42 studies. The most frequently used methods for detecting OTC were immunohistochemical examination (IHC) and/or polymerase chain reaction (PCR) with a wide range of markers. Using IHC for OTC detection, in patients and in LN, the prevalence varied from 9 to 88% and 0.4 to 42%, respectively. With PCR, it ranged from 17 to 46% in patients, and from 3 to 33% in LN. In the studies assessing the predictive role of OTC in gastric cancer recurrence (n = 24), 8 studies found no statistical association, while 18 concluded that OTC presence was associated with poorer prognosis. However, only 6 studies presented a significantly different 5-year survival rate between patients with and without LN micrometastasis. OTC seems to occur in gastric cancer patients with a variable prevalence, depending on the definition, methods and setting. The majority of the retrieved studies (75%) evaluating the predictive role of OTC conclude that its presence is associated with a worse prognosis. © 2015 S. Karger AG, Basel.
    Oncology 07/2015; 89(5). DOI:10.1159/000433543 · 2.42 Impact Factor
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    ABSTRACT: Helicobacter pylori exploits host glycoconjugates to colonize the gastric niche. Infection can persist for decades promoting chronic inflammation, and in a subset of individuals lesions can silently progress to cancer. This study shows that H. pylori chronic infection and gastric tissue inflammation result in a remodeling of the gastric glycophenotype with increased expression of sialyl-Lewis a/x antigens due to transcriptional up-regulation of the B3GNT5, B3GALT5, and FUT3 genes. We observed that H. pylori infected individuals present a marked gastric local pro-inflammatory signature with significantly higher TNF-α levels and demonstrated that TNF-induced activation of the NF-kappaB pathway results in B3GNT5 transcriptional up-regulation. Furthermore, we show that this gastric glycosylation shift, characterized by increased sialylation patterns, favors SabA-mediated H. pylori attachment to human inflamed gastric mucosa. This study provides novel clinically relevant insights into the regulatory mechanisms underlying H. pylori modulation of host glycosylation machinery, and phenotypic alterations crucial for life-long infection. Moreover, the biosynthetic pathways here identified as responsible for gastric mucosa increased sialylation, in response to H. pylori infection, can be exploited as drug targets for hindering bacteria adhesion and counteract the infection chronicity. Copyright © 2015. Published by Elsevier B.V.
    Biochimica et Biophysica Acta 07/2015; 1852(9). DOI:10.1016/j.bbadis.2015.07.001 · 4.66 Impact Factor
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    F M Castro-Poças · Mário Dinis-Ribeiro · Tarcísio Araújo · Isabel Pedroto ·
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    ABSTRACT: To characterize colon and rectum walls, pericolic and perirectal spaces, using endoscopic ultrasonography miniprobes. Sixty individuals (50% males), aged 18-80, were included. Using 12 and 20 MHz endoscopic ultrasonography miniprobes, all different colon segments (ascending, transverse, descending, sigmoid) and rectum were evaluated according to the number and thickness of the different layers in intestinal wall, to the presence and (largest) diameter of vessels in the submucosa and of peri-intestinal nodes. The 20 MHz miniprobe identified a higher number of layers than the 12 MHz miniprobe, with medians of 7 and 5 respectively (p < 0.001). The rectal wall (p = 0.001), its muscularis propria (p < 0.001) and mucosa (p = 0.01) were significantly thicker than the different segments of the colon, which had no significant differences between them. Patients aged 41-60 presented thicker colonic wall and muscularis propria in descending (p = 0.001 and p = 0.004) and rectum (p = 0.01 and p = 0.01). Submucosal vessels were identified in 30% of individuals in descending and rectum, and in 12% in ascending. Adenopathies were observed in 9% of the colon segments and 5% in rectum. A higher frequency enabled the identification of a higher number of layers. Rectal wall is thicker than the one from all the segments of the colon and there are no differences between these, namely in the ascending colon. Moreover, periintestinal adenopathies were rarely identified but present in asymptomatic individuals. All together, these results describe for the first time features which are relevant during staging and therapeutic management of colonic lesions.
    Revista espanola de enfermedades digestivas: organo oficial de la Sociedad Espanola de Patologia Digestiva 06/2015; 107(8). DOI:10.17235/reed.2015.3721/2015 · 1.41 Impact Factor
  • Diogo Abrantes · Pedro Pimentel-Nunes · Mário Dinis-Ribeiro · Miguel Coimbra ·
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    ABSTRACT: Gastric cancer is a serious disease that most people usually do not know they have until they start to get symptoms. Gastroenterology imaging is an essential tool for this battle, since an early diagnosis typically leads to a good prognosis. However, this is a rapidly evolving technological area with novel imaging devices such as capsule, narrow-band imaging or high-definition endoscopy. Adapting to these technologies has a high time-price cost, even for experienced clinicians, motivating the appearance of interactive environments that can accelerate these training processes. The GEMINI (Gastroenterology Made Interactive) project aims to create an interactive clinical decision support system (CDSS) that can be used to help with the diagnosis within a gastroenterology room during real endoscopic examinations. We used human computer interaction (HCI) support methodologies in order to identify interaction opportunities. As a final conclusion, the most promising avenue for interactions with CDSS is probably using mobile devices such as tablets, controlled by a nurse at the physician's request. As future work, we will prototype and evaluate such a system in a real hospital environment.
    Studies in health technology and informatics 05/2015; 210:652-6. DOI:10.3233/978-1-61499-512-8-652
  • Mário Dinis-Ribeiro · Ernst J Kuipers ·
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    ABSTRACT: In an aging European population, an increasing number of individuals will suffer from gastric cancer in the coming two decades. Recent research has determined the risk for gastric cancer in patients with different stages of gastric atrophy. Based on these data, it is now recommended that surveillance is offered to individuals with advanced stages of atrophic gastritis. Endoscopic biopsies of the gastric antrum and corpus are recommended in order to assess the severity and extent of gastric atrophy. This enables identification of those at highest risk of progressing to cancer. However, systematic reviews have shown that in recent years many researchers have assessed new endoscopic technologies for their accuracy in determining the severity and extent of gastric atrophy and metaplasia without the use of histology. Simple, reliable and accurate endoscopic features have been identified that can be used to either target biopsies or avoid biopsy sampling in the absence of endoscopic features of atrophy and intestinal metaplasia. This may largely simplify everyday practice. Randomized trials or large observational studies are now needed to demonstrate the accuracy of endoscopic assessment of the entire gastric mucosa and its impact on patient management. © Georg Thieme Verlag KG Stuttgart · New York.
    Endoscopy 05/2015; 47(06). DOI:10.1055/s-0034-1392151 · 5.05 Impact Factor

  • Gastrointestinal Endoscopy 05/2015; 81(5):AB463. DOI:10.1016/j.gie.2015.03.1668 · 5.37 Impact Factor

  • Gastrointestinal Endoscopy 05/2015; 81(5):AB125. DOI:10.1016/j.gie.2015.03.031 · 5.37 Impact Factor

  • Gastroenterology; 04/2015

  • Gastroenterology; 04/2015
  • Amelia Tavares · Fernando Viveiros · Jorge Maciel · Mário Dinis-Ribeiro ·
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    ABSTRACT: Despite the medical-surgical advances, even after R0 gastric resections, some patients without apparent metastatic disease develop cancer recurrence and eventually die. We aimed to define recurrence in patients with node-negative gastric adenocarcinoma and to determine whether any clinicopathological features are predictive for recurrence. This was a retrospective cohort study on patients with gastric adenocarcinoma, consecutively diagnosed at our institution, staged as N0M0 between January 2000 and December 2008. We recruited 129 patients; 53% were men and 56% were older than 60 years. A total of 22% of the patients developed recurrence, with a mortality rate of 93%. Overall, 71% of the patients, N0, with recurrence presented lymphatic permeation. In univariate analysis, on comparing recurrent patients with those with no recurrence, age, size, T status, lymphatic, and venous permeation were factors that were associated significantly with recurrence, but in multivariate analysis, only age (odds ratio:19.5; 95% confidence interval: 2.3-168; P=0.008) and venous permeation (odds ratio: 6.34; 95% confidence interval: 1.8-22.8; P=0.005) were associated with recurrence. On the basis of only these two factors, the proportion of missed recurrent patients by age and venous permeation was 13 and 39%, respectively. A total of 22% of patients, N0, developed recurrence of their disease. Age and venous permeation were independent risk factors for recurrence, but on the basis of these factors, up to 40% of patients may be missed for recurrence. New methods to predict recurrence are needed.
    European journal of gastroenterology & hepatology 04/2015; 27(4):425-9. DOI:10.1097/MEG.0000000000000307 · 2.25 Impact Factor

Publication Stats

2k Citations
612.41 Total Impact Points


  • 2008-2015
    • University of Porto
      • Faculty of Medicine
      Oporto, Porto, Portugal
  • 2004-2015
    • Instituto Português de Oncologia
      • • Department of Pathology
      • • Molecular Oncology Group
      Oporto, Porto, Portugal
    • Showa University
      Shinagawa, Tōkyō, Japan
  • 2014
    • American Society for Gastrointestinal Endoscopy
      Society Hill, New Jersey, United States
  • 2012-2014
    • Centre for Research in Health Technologies and Information Systems (CINTESIS)
      Oporto, Porto, Portugal
  • 2010-2012
    • Centro Hospitalar do Porto
      Oporto, Porto, Portugal
  • 2006-2012
    • Porto Military Hospital
      Oporto, Porto, Portugal
  • 2002
    • Hospital de São João
      Oporto, Porto, Portugal