Spencer Cheng | Universidade de São Paulo (original) (raw)

Papers by Spencer Cheng

Teaching models in endoscopy are important tools to minimize risks derived from endoscopic proced... more Teaching models in endoscopy are important tools to minimize risks derived from endoscopic procedures, taking into account that therapeutic endoscopy, also known as surgical endoscopy, has greatly developed during the last decade. This results from the fact that minimally invasive procedures present relevant contributions and promote more comfort to patients. In this context, ex vivo teaching models and virtual simulators are important tools to the safe acquisition of abilities. In this article, the Brazilian Society of Digestive Endoscopy presents and describes its first course of therapeutic ERCP and EUS in models of laboratory teaching.

World journal of gastroenterology, Jan 28, 2018

To compare the cannulation success, biochemical profile, and complications of the papillary fistu... more To compare the cannulation success, biochemical profile, and complications of the papillary fistulotomy technique catheter and guidewire standard access. From July 2010 to May 2017, patients were prospectively randomized into two groups: Cannulation with a catheter and guidewire (Group I) and papillary fistulotomy (Group II). Amylase, lipase and C-reactive protein at T0, as well as 12 h and 24 h after endoscopic retrograde cholangiopancreatography, and complications (pancreatitis, bleeding, perforation) were recorded. We included 102 patients (66 females and 36 males, mean age 59.11 ± 18.7 years). Group I and Group II had 51 patients each. The successful cannulation rates were 76.5% and 100%, respectively ( = 0.0002). Twelve patients (23.5%) in Group I had a difficult cannulation and underwent fistulotomy, which led to successful secondary biliary access (Failure Group). The complication rate was 13.7% (2 perforations and 5 mild pancreatitis) 2.0% (1 patient with perforation and pan...

Case Reports in Medicine, 2012

Introduction. Considered as a rare event, gastric syphilis (GS) is reported as an organic form of... more Introduction. Considered as a rare event, gastric syphilis (GS) is reported as an organic form of involvement. Low incidence of GS emphasizes the importance of histopathological analysis.Objective. We aim to characterize GS endoscopic aspects in an immunocompetent patient.Case Report. A 23-year-old man presented with epigastric pain associated with nausea, anorexia, generalized malaise and 11 kg weight loss that started 1 month prior to his clinical consultation. Physical examination was normal except for mild abdominal tenderness in epigastrium. Endoscopy observed diminished gastric expandability and diffuse mucosal lesions, from cardia to pylorus. Gastric mucosa was thickened, friable, with nodular aspect, and associated with ulcers lesions. Gastric biopsies were performed, and histopathological analysis resulted in dense inflammatory infiltration rich in plasmocytes. Syphilis serologies were positive for VDRL andTreponema pallidumreagents. Immunohistochemical tests were positive ...

Introdução: A colocação de próteses através da junção esofagogástrica propicia o refluxo gastroes... more Introdução: A colocação de próteses através da junção esofagogástrica propicia o refluxo gastroesofágico. Objetivos e métodos: Avaliação da paliação da disfagia, manifestações broncoaspirativas, parâmetros nutricionais e qualidade de vida de 30 pacientes com tumores avançados da junção esofagogástrica tratados por prótese metálica auto-expansível com válvula anti-refluxo de 2001 a 2004. Resultados: Melhora da disfagia e regurgitação. Sem alteração na tosse, eructação, pirose, parâmetros nutricionais e qualidade de vida. Conclusões: A prótese com válvula anti-refluxo foi eficaz na paliação da disfagia, impediu a ocorrência de manifestações broncoaspirativas, não interferiu nos parâmetros nutricionais e qualidade de vidaBackground: Placement of stents through the gastroesophageal junction can cause reflux. Objective and methods: Evaluate dysphagia palliation, aspiration symptoms, nutritional parameters and quality of life in 30 patients treated for advanced gastroesophageal junction t...

Gastrointestinal Endoscopy, 2018

Arquivos Brasileiros de Cirurgia Digestiva Express, 2017

Arquivos Brasileiros de Cirurgia Digestiva Express, 2017

Arquivos Brasileiros de Cirurgia Digestiva Express, 2017

Probabilistic representations, such as Bayesian and Markov networks, are fundamental to much of s... more Probabilistic representations, such as Bayesian and Markov networks, are fundamental to much of statistical machine learning. Thus, learning probabilistic representations directly from data is a deep challenge, the main computational bottleneck being inference that is intractable. Tractable learning is a powerful new paradigm that attempts to learn distributions that support efficient probabilistic querying. By leveraging local structure, representations such as sum-product networks (SPNs) can capture high treewidth models with many hidden layers, essentially a deep architecture, while still admitting a range of probabilistic queries to be computable in time polynomial in the network size. The leaf nodes in SPNs, from which more intricate mixtures are formed, are tractable univariate distributions, and so the literature has focused on Bernoulli and Gaussian random variables. This is clearly a restriction for handling mixed discrete-continuous data, especially if the continuous features are generated from non-parametric and non-Gaussian distribution families. In this work, we present a framework that systematically integrates SPN structure learning with weighted model integration, a recently introduced computational abstraction for performing inference in hybrid domains, by means of piecewise polynomial approximations of density functions of arbitrary shape. Our framework is instantiated by exploiting the notion of propositional abstractions, thus minimally interfering with the SPN structure learning module, and supports a powerful query interface for conditioning on interval constraints. Our empirical results show that our approach is effective, and allows a study of the trade off between the granularity of the learned model and its predictive power.

World Journal of Gastrointestinal Endoscopy, 2019

Author contributions: Logiudice FP acquisition of data, analysis, interpretation of data, draftin... more Author contributions: Logiudice FP acquisition of data, analysis, interpretation of data, drafting the article, revising the article, final approval; Bernardo WM analysis and interpretation of data, drafting the article, final approval; Galetti F acquisition of data, drafting the article, revising the article; Sagae VM acquisition of data, drafting the article, revising the article; Matsubayashi CO acquisition of data, drafting the article, revising the article; Madruga Neto AC acquisition of data, drafting the article, revising the article, final approval; Brunaldi VO analysis and interpretation of data, critical revision, final approval; de Moura DTH analysis and interpretation of data, revised the article; Franzini T

Endoscopy International Open, 2015

Clinics (Sao Paulo, Brazil), 2018

Our aim in this study was to compare the efficiency of 25G versus 22G needles in diagnosing solid... more Our aim in this study was to compare the efficiency of 25G versus 22G needles in diagnosing solid pancreatic lesions by EUS-FNA. We performed a systematic review and meta-analysis. Studies were identified in five databases using an extensive search strategy. Only randomized trials comparing 22G and 25G needles were included. The results were analyzed by fixed and random effects. A total of 504 studies were found in the search, among which 4 randomized studies were selected for inclusion in the analysis. A total of 462 patients were evaluated (233: 25G needle/229: 22G needle). The diagnostic sensitivity was 93% for the 25G needle and 91% for the 22G needle. The specificity of the 25G needle was 87%, and that of the 22G needle was 83%. The positive likelihood ratio was 4.57 for the 25G needle and 4.26 for the 22G needle. The area under the sROC curve for the 25G needle was 0.9705, and it was 0.9795 for the 22G needle, with no statistically significant difference between them (p=0.497)...

Diseases of the Esophagus, 2004

Gastrointestinal Endoscopy, 2021

World Journal of Gastroenterology, 2021

Acute post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP) is a feared and pote... more Acute post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP) is a feared and potentially fatal complication that can be as high as up to 30% in high-risk patients. Pre-examination measures, during the examination and after the examination are the key to technical and clinical success with a decrease in adverse events. Several studies have debated on the subject, however, numerous topics remain controversial, such as the effectiveness of prophylactic medications and the amylase dosage time. This review was designed to provide an update on the current scientific evidence regarding PEP available in the literature.

Revista de gastroenterologia del Peru : organo oficial de la Sociedad de Gastroenterologia del Peru, Nov 3, 2016

Teaching models in endoscopy are important tools to minimize risks derived from endoscopic proced... more Teaching models in endoscopy are important tools to minimize risks derived from endoscopic procedures, taking into account that therapeutic endoscopy, also known as surgical endoscopy, has greatly developed during the last decade. This results from the fact that minimally invasive procedures present relevant contributions and promote more comfort to patients. In this context, ex vivo teaching models and virtual simulators are important tools to the safe acquisition of abilities. In this article, the Brazilian Society of Digestive Endoscopy presents and describes its first course of therapeutic ERCP and EUS in models of laboratory teaching.

World journal of gastroenterology, Jan 28, 2018

To compare the cannulation success, biochemical profile, and complications of the papillary fistu... more To compare the cannulation success, biochemical profile, and complications of the papillary fistulotomy technique catheter and guidewire standard access. From July 2010 to May 2017, patients were prospectively randomized into two groups: Cannulation with a catheter and guidewire (Group I) and papillary fistulotomy (Group II). Amylase, lipase and C-reactive protein at T0, as well as 12 h and 24 h after endoscopic retrograde cholangiopancreatography, and complications (pancreatitis, bleeding, perforation) were recorded. We included 102 patients (66 females and 36 males, mean age 59.11 ± 18.7 years). Group I and Group II had 51 patients each. The successful cannulation rates were 76.5% and 100%, respectively ( = 0.0002). Twelve patients (23.5%) in Group I had a difficult cannulation and underwent fistulotomy, which led to successful secondary biliary access (Failure Group). The complication rate was 13.7% (2 perforations and 5 mild pancreatitis) 2.0% (1 patient with perforation and pan...

Case Reports in Medicine, 2012

Introduction. Considered as a rare event, gastric syphilis (GS) is reported as an organic form of... more Introduction. Considered as a rare event, gastric syphilis (GS) is reported as an organic form of involvement. Low incidence of GS emphasizes the importance of histopathological analysis.Objective. We aim to characterize GS endoscopic aspects in an immunocompetent patient.Case Report. A 23-year-old man presented with epigastric pain associated with nausea, anorexia, generalized malaise and 11 kg weight loss that started 1 month prior to his clinical consultation. Physical examination was normal except for mild abdominal tenderness in epigastrium. Endoscopy observed diminished gastric expandability and diffuse mucosal lesions, from cardia to pylorus. Gastric mucosa was thickened, friable, with nodular aspect, and associated with ulcers lesions. Gastric biopsies were performed, and histopathological analysis resulted in dense inflammatory infiltration rich in plasmocytes. Syphilis serologies were positive for VDRL andTreponema pallidumreagents. Immunohistochemical tests were positive ...

Introdução: A colocação de próteses através da junção esofagogástrica propicia o refluxo gastroes... more Introdução: A colocação de próteses através da junção esofagogástrica propicia o refluxo gastroesofágico. Objetivos e métodos: Avaliação da paliação da disfagia, manifestações broncoaspirativas, parâmetros nutricionais e qualidade de vida de 30 pacientes com tumores avançados da junção esofagogástrica tratados por prótese metálica auto-expansível com válvula anti-refluxo de 2001 a 2004. Resultados: Melhora da disfagia e regurgitação. Sem alteração na tosse, eructação, pirose, parâmetros nutricionais e qualidade de vida. Conclusões: A prótese com válvula anti-refluxo foi eficaz na paliação da disfagia, impediu a ocorrência de manifestações broncoaspirativas, não interferiu nos parâmetros nutricionais e qualidade de vidaBackground: Placement of stents through the gastroesophageal junction can cause reflux. Objective and methods: Evaluate dysphagia palliation, aspiration symptoms, nutritional parameters and quality of life in 30 patients treated for advanced gastroesophageal junction t...

Gastrointestinal Endoscopy, 2018

Arquivos Brasileiros de Cirurgia Digestiva Express, 2017

Arquivos Brasileiros de Cirurgia Digestiva Express, 2017

Arquivos Brasileiros de Cirurgia Digestiva Express, 2017

Probabilistic representations, such as Bayesian and Markov networks, are fundamental to much of s... more Probabilistic representations, such as Bayesian and Markov networks, are fundamental to much of statistical machine learning. Thus, learning probabilistic representations directly from data is a deep challenge, the main computational bottleneck being inference that is intractable. Tractable learning is a powerful new paradigm that attempts to learn distributions that support efficient probabilistic querying. By leveraging local structure, representations such as sum-product networks (SPNs) can capture high treewidth models with many hidden layers, essentially a deep architecture, while still admitting a range of probabilistic queries to be computable in time polynomial in the network size. The leaf nodes in SPNs, from which more intricate mixtures are formed, are tractable univariate distributions, and so the literature has focused on Bernoulli and Gaussian random variables. This is clearly a restriction for handling mixed discrete-continuous data, especially if the continuous features are generated from non-parametric and non-Gaussian distribution families. In this work, we present a framework that systematically integrates SPN structure learning with weighted model integration, a recently introduced computational abstraction for performing inference in hybrid domains, by means of piecewise polynomial approximations of density functions of arbitrary shape. Our framework is instantiated by exploiting the notion of propositional abstractions, thus minimally interfering with the SPN structure learning module, and supports a powerful query interface for conditioning on interval constraints. Our empirical results show that our approach is effective, and allows a study of the trade off between the granularity of the learned model and its predictive power.

World Journal of Gastrointestinal Endoscopy, 2019

Author contributions: Logiudice FP acquisition of data, analysis, interpretation of data, draftin... more Author contributions: Logiudice FP acquisition of data, analysis, interpretation of data, drafting the article, revising the article, final approval; Bernardo WM analysis and interpretation of data, drafting the article, final approval; Galetti F acquisition of data, drafting the article, revising the article; Sagae VM acquisition of data, drafting the article, revising the article; Matsubayashi CO acquisition of data, drafting the article, revising the article; Madruga Neto AC acquisition of data, drafting the article, revising the article, final approval; Brunaldi VO analysis and interpretation of data, critical revision, final approval; de Moura DTH analysis and interpretation of data, revised the article; Franzini T

Endoscopy International Open, 2015

Clinics (Sao Paulo, Brazil), 2018

Our aim in this study was to compare the efficiency of 25G versus 22G needles in diagnosing solid... more Our aim in this study was to compare the efficiency of 25G versus 22G needles in diagnosing solid pancreatic lesions by EUS-FNA. We performed a systematic review and meta-analysis. Studies were identified in five databases using an extensive search strategy. Only randomized trials comparing 22G and 25G needles were included. The results were analyzed by fixed and random effects. A total of 504 studies were found in the search, among which 4 randomized studies were selected for inclusion in the analysis. A total of 462 patients were evaluated (233: 25G needle/229: 22G needle). The diagnostic sensitivity was 93% for the 25G needle and 91% for the 22G needle. The specificity of the 25G needle was 87%, and that of the 22G needle was 83%. The positive likelihood ratio was 4.57 for the 25G needle and 4.26 for the 22G needle. The area under the sROC curve for the 25G needle was 0.9705, and it was 0.9795 for the 22G needle, with no statistically significant difference between them (p=0.497)...

Diseases of the Esophagus, 2004

Gastrointestinal Endoscopy, 2021

World Journal of Gastroenterology, 2021

Acute post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP) is a feared and pote... more Acute post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP) is a feared and potentially fatal complication that can be as high as up to 30% in high-risk patients. Pre-examination measures, during the examination and after the examination are the key to technical and clinical success with a decrease in adverse events. Several studies have debated on the subject, however, numerous topics remain controversial, such as the effectiveness of prophylactic medications and the amylase dosage time. This review was designed to provide an update on the current scientific evidence regarding PEP available in the literature.

Revista de gastroenterologia del Peru : organo oficial de la Sociedad de Gastroenterologia del Peru, Nov 3, 2016