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Cold-formed steels (CFS) or light gauge steels (LGS) are steel sections created through processes without heat application, such as roll forming or press-braking. In the past few decades, the utilization of CFS as a structural material has expanded due to its advantages over the other materials used in the construction industry, consequently increasing the number of studies conducted by many researchers. CFS studies have focused on many research areas, including designing, and analyzing members and systems, connections, sustainability, residual stresses, and post-fire data. As a result, several authors have also conducted a literature review involving these areas. However, a literature review for more recent studies involving elevated temperature exposure of CFS has not been conducted. This paper seeks to compile and review the recent publications regarding CFS behavior and performance at high temperatures events. Sixty-nine (69) journal articles published from 2017 to 2023 were retrieved from the Scopus database and systematically reviewed through text mining with the aid of VOS Viewer. Prior studies utilizing finite element analysis and experimental methods to investigate the performance at elevated temperature events of varying CFS sections, systems, and steel grades have been summarized. In addition, this paper also briefly discussed the findings of the recent research works involving member connections of CFS. Key points from the literature review have been emphasized such as the outcome of experimental and numerical validation of existing design rules from different codes such as American Iron and Steel Institute (AISI), Eurocodes, and Australian codes which could vary depending on the CFS section and steel grades. Important points of previous studies regarding the CFS walls, insulations, and screwed connections have also been noted in this paper. Based on the review, research gaps in the prior studies involving elevated temperature exposure of CFS have been identified, such as lack of CFS investigation under fatigue and cyclic loading. These were then recommended as future direction and concentration of CFS at elevated temperatures research works.
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Adapting sustainable construction, which involves responsible consumption of natural resources and reducing carbon emissions, could be a unified action to address the intensifying effects of global warming and the increasing rate of waste pollution worldwide. Aiming to lessen the emission from the construction and waste sector and eliminate plastics in the open environment, a foam fly ash geopolymer with recycled High-Density Polyethylene (HDPE) plastics was developed in this study. The effects of the increasing percentages of HDPE on the thermo-physicomechanical properties of foam geopolymer were investigated. The samples' measured density, compressive strength, and thermal conductivity at 0.25% and 0.50% HDPE content was 1593.96 kg/m3 and 1479.06 kg/m3, 12.67 MPa and 7.89 MPa, and 0.352 W/mK and 0.373 W/mK, respectively. Obtained results are comparable to structural and insulating lightweight concretes with a density of less than 1600 kg/m3, compressive strength of greater than 3.5 MPa, and thermal conductivity of less than 0.75 W/mK. Thus, this research concluded that the developed foam geopolymers from recycled HDPE plastics could be a sustainable alternative material and be optimized in the building and construction industry.
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Current research into the production of sustainable construction materials for retrofitting and strengthening historic structures has been rising, with geopolymer technology being seen as an advantageous alternative to traditional concrete. Fiber reinforcement using this novel cementitious material involves a low embodied carbon footprint while ensuring cohesiveness with local materials. This study aims to develop fly ash-based geopolymers reinforced with six different types of fibers: polyvinyl alcohol, polypropylene, chopped basalt, carbon fiber, and copper-coated stainless steel. The samples are produced by mixing the geopolymer mortar in random distribution and content. Twenty-eight geopolymer mixes are evaluated through compressive strength, split-tensile strength, and modulus of elasticity to determine the fiber mix with the best performance compared with pure geopolymer mortar as a control. Polyvinyl alcohol and copper-coated stainless-steel fiber samples had considerably high mechanical properties and fracture toughness under applied tensile loads. However, the polypropylene fiber source did not perform well and had lower mechanical properties. One-way ANOVA verifies these results. Based on these findings, polyvinyl alcohol and stainless-steel fibers are viable options for fiber reinforcement in historical structures, and further optimization and testing are recommended before application as a reinforcement material in historic structures.
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Abstract The knowledge of the testicular and ovarian morphology of a particular fish species is of paramount importance. Such analyze enables the development of studies and techniques aiming the improvement of their reproduction, management, commercialization and even their conservation. This study performed the ovarian and testicular characterization of the ornamental Amazon fish Serrapinnus kriegi. A total of three males and three females had their gonads analyzed by optical microscopy. Females present ovaries filled with oocytes in asynchronous development, indicating partial spawning in the species. Moreover, the micropyle and micropilar cell formation was observed in primary growing oocytes, representing a precocious oocyte development; and the zona radiata in the final vitellogenic oocytes is thicker than other related species, evidencing the development of a better protection to the embryos in function of the waters' turbulence that characterize it spawning sites in the Amazonian streams. The male specimens' present anastomosed tubular testes with unrestricted spermatogonia spread along the entire seminiferous tubules. The present data elucidate the dynamic of spermatogenesis and oogenesis of an ornamental Amazonian species, through the description of the male and female germ cells development.
Resumo O conhecimento da morfologia testicular e ovariana de uma determinada espécie de peixe é de suma importância, pois através destas análises é possível o desenvolvimento de estudos e técnicas visando o melhoramento de sua reprodução, manejo e comercialização e até mesmo auxiliar em sua conservação. Este estudo realizou a caracterização ovariana e testicular do peixe Amazônico ornamental Serrapinnus kriegi. Um total de três machos e três fêmeas tiveram suas gônadas analisadas através de microscopia óptica. As fêmeas apresentam ovários preenchidos por oócitos em desenvolvimento assincrônico, indicando desova parcelada da espécie. Além disso, observou-se a formação de micrópila e célula micropilar em oócitos em crescimento primário, representando o desenvolvimento precoce do oócito; a zona radiata nos oócitos vitelogênicos finais é mais espessa em comparação a outras espécies relacionadas, evidenciando o desenvolvimento de uma melhor proteção aos embriões, em função das águas turbulentas que caracterizam seu local de desova nos córregos amazônicos. Os machos apresentam testículos do tipo tubular anastomosado com espermatogônias irrestritas, espalhadas por todo o túbulo seminífero. Os dados apresentados elucidam a dinâmica da espermatogênese e oogênese de uma espécie de peixe ornamental amazônica, por meio da descrição das células germinativas masculinas e femininas.
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Animales , Masculino , Femenino , Characidae , Oocitos , Oogénesis , Ovario , Testículo , GónadasRESUMEN
The knowledge of the testicular and ovarian morphology of a particular fish species is of paramount importance. Such analyze enables the development of studies and techniques aiming the improvement of their reproduction, management, commercialization and even their conservation. This study performed the ovarian and testicular characterization of the ornamental Amazon fish Serrapinnus kriegi. A total of three males and three females had their gonads analyzed by optical microscopy. Females present ovaries filled with oocytes in asynchronous development, indicating partial spawning in the species. Moreover, the micropyle and micropilar cell formation was observed in primary growing oocytes, representing a precocious oocyte development; and the zona radiata in the final vitellogenic oocytes is thicker than other related species, evidencing the development of a better protection to the embryos in function of the waters turbulence that characterize it spawning sites in the Amazonian streams. The male specimens present anastomosed tubular testes with unrestricted spermatogonia spread along the entire seminiferous tubules. The present data elucidate the dynamic of spermatogenesis and oogenesis of an ornamental Amazonian species, through the description of the male and female germ cells development.
O conhecimento da morfologia testicular e ovariana de uma determinada espécie de peixe é de suma importância, pois através destas análises é possível o desenvolvimento de estudos e técnicas visando o melhoramento de sua reprodução, manejo e comercialização e até mesmo auxiliar em sua conservação. Este estudo realizou a caracterização ovariana e testicular do peixe Amazônico ornamental Serrapinnus kriegi. Um total de três machos e três fêmeas tiveram suas gônadas analisadas através de microscopia óptica. As fêmeas apresentam ovários preenchidos por oócitos em desenvolvimento assincrônico, indicando desova parcelada da espécie. Além disso, observou-se a formação de micrópila e célula micropilar em oócitos em crescimento primário, representando o desenvolvimento precoce do oócito; a zona radiata nos oócitos vitelogênicos finais é mais espessa em comparação a outras espécies relacionadas, evidenciando o desenvolvimento de uma melhor proteção aos embriões, em função das águas turbulentas que caracterizam seu local de desova nos córregos amazônicos. Os machos apresentam testículos do tipo tubular anastomosado com espermatogônias irrestritas, espalhadas por todo o túbulo seminífero. Os dados apresentados elucidam a dinâmica da espermatogênese e oogênese de uma espécie de peixe ornamental amazônica, por meio da descrição das células germinativas masculinas e femininas.
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Masculino , Femenino , Animales , Characiformes/anatomía & histología , Characiformes/genética , Espermatogénesis , OogénesisRESUMEN
Abstract The knowledge of the testicular and ovarian morphology of a particular fish species is of paramount importance. Such analyze enables the development of studies and techniques aiming the improvement of their reproduction, management, commercialization and even their conservation. This study performed the ovarian and testicular characterization of the ornamental Amazon fish Serrapinnus kriegi. A total of three males and three females had their gonads analyzed by optical microscopy. Females present ovaries filled with oocytes in asynchronous development, indicating partial spawning in the species. Moreover, the micropyle and micropilar cell formation was observed in primary growing oocytes, representing a precocious oocyte development; and the zona radiata in the final vitellogenic oocytes is thicker than other related species, evidencing the development of a better protection to the embryos in function of the waters turbulence that characterize it spawning sites in the Amazonian streams. The male specimens present anastomosed tubular testes with unrestricted spermatogonia spread along the entire seminiferous tubules. The present data elucidate the dynamic of spermatogenesis and oogenesis of an ornamental Amazonian species, through the description of the male and female germ cells development.
Resumo O conhecimento da morfologia testicular e ovariana de uma determinada espécie de peixe é de suma importância, pois através destas análises é possível o desenvolvimento de estudos e técnicas visando o melhoramento de sua reprodução, manejo e comercialização e até mesmo auxiliar em sua conservação. Este estudo realizou a caracterização ovariana e testicular do peixe Amazônico ornamental Serrapinnus kriegi. Um total de três machos e três fêmeas tiveram suas gônadas analisadas através de microscopia óptica. As fêmeas apresentam ovários preenchidos por oócitos em desenvolvimento assincrônico, indicando desova parcelada da espécie. Além disso, observou-se a formação de micrópila e célula micropilar em oócitos em crescimento primário, representando o desenvolvimento precoce do oócito; a zona radiata nos oócitos vitelogênicos finais é mais espessa em comparação a outras espécies relacionadas, evidenciando o desenvolvimento de uma melhor proteção aos embriões, em função das águas turbulentas que caracterizam seu local de desova nos córregos amazônicos. Os machos apresentam testículos do tipo tubular anastomosado com espermatogônias irrestritas, espalhadas por todo o túbulo seminífero. Os dados apresentados elucidam a dinâmica da espermatogênese e oogênese de uma espécie de peixe ornamental amazônica, por meio da descrição das células germinativas masculinas e femininas.
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Currently, available fish anesthetics can produce important side effects, including respiratory arrest and distress. Easy-to-implement alternatives with low toxicity are needed to ensure fish health as well as to help artisanal fisheries and fish sellers in handling and transporting fishes, and native plants seems to be the best alternative. We aimed to implement an anesthetic protocol using crude ethanolic extracts from flowers and leaves of two Amazonian plants, the Acmella oleracea and Piper alatabaccum. We first tested the extracts for anesthesia, using the zebrafish as model. Even though in some treatments the animals apparently entered deep anesthesia, many of them presented aberrant behaviors and even died. Thus, we performed new experiments testing the extracts effects on seizure-like behaviors of the fish. Only the leaf extract of A. oleracea has potential effects for fish anesthesia. Both the flower extract from this plant and the leaf extract from P. alatabaccum induced seizure-like behavior in the animals. In conclusion, besides bringing a possible new anesthetic protocol for fish, our work draws attention for the neurotoxic effects the anesthetic solutions may cause, since several studies defend other Piper species as anesthetic for fish and A. oleracea flowers' extract was already pointed as fish anesthetic.
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Anestesia , Anestésicos , Asteraceae , Piper , Animales , Extractos Vegetales/uso terapéutico , Extractos Vegetales/toxicidad , Plantas , Convulsiones/inducido químicamente , Convulsiones/tratamiento farmacológico , Pez CebraRESUMEN
Approximately 2.78 Mt of coal fly ash is produced in the Philippines, with a low utilization rate. Using fly ash-based geopolymer for construction will lessen the load sent to landfills and will result in lower GHG emissions compared to OPC. It is necessary to characterize the fly ash and optimize the geopolymer components to determine if it can replace OPC for in situ applications. The activator-to-precursor ratio, the water-to-solids ratio, and the sodium hydroxide-to-sodium silicate ratio were optimized using a randomized I-optimal design from the experimental results of 21 runs with five replicates, for a total of 105 specimens of 50 mm × 50 mm × 50 mm paste cubes. The engineering properties chosen as the optimization responses were the unconfined compressive strength (UCS), the initial setting time, and the final setting time. The samples were also ambient-cured with the outdoor temperature ranging from 30 °C to 35 °C and relative humidity of 50% ± 10% to simulate the on-site environment. Runs with high unconfined compressive strength (UCS) and short setting times were observed to have a low water-to-solids (W/S) ratio. All runs with a UCS greater than 20 MPa had a W/S ratio of 0.2, and the runs with the lowest UCS had a W/S of 0.4. The initial setting time for design mixes with a W/S ratio of 0.2 ranged from 8 to 105 min. Meanwhile, five out of seven design mixes with a W/S ratio of 0.4 took longer than 1440 min to set. Specimens with an alkali activator ratio (NaOH/WG) of 0.5 (1:2) and 0.4 (1:2.5) also had significantly lower setting times than those with an alkali activator ratio of 1. The RSM model was verified through confirmatory tests. The results of the confirmatory tests are agreeable, with deviations from the expected UCS ranging from 0 to 38.12%. The generated model is a reliable reference to estimate the UCS and setting time of low-calcium FA geopolymer paste for in situ applications.
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The knowledge of the testicular and ovarian morphology of a particular fish species is of paramount importance. Such analyze enables the development of studies and techniques aiming the improvement of their reproduction, management, commercialization and even their conservation. This study performed the ovarian and testicular characterization of the ornamental Amazon fish Serrapinnus kriegi. A total of three males and three females had their gonads analyzed by optical microscopy. Females present ovaries filled with oocytes in asynchronous development, indicating partial spawning in the species. Moreover, the micropyle and micropilar cell formation was observed in primary growing oocytes, representing a precocious oocyte development; and the zona radiata in the final vitellogenic oocytes is thicker than other related species, evidencing the development of a better protection to the embryos in function of the waters' turbulence that characterize it spawning sites in the Amazonian streams. The male specimens' present anastomosed tubular testes with unrestricted spermatogonia spread along the entire seminiferous tubules. The present data elucidate the dynamic of spermatogenesis and oogenesis of an ornamental Amazonian species, through the description of the male and female germ cells development.
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Characidae , Animales , Femenino , Gónadas , Masculino , Oocitos , Oogénesis , Ovario , TestículoRESUMEN
Construction and demolition waste (CDW) accounts for at least 30% of the total solid waste produced around the world. At around 924 million tons in the European Union in 2016 and 2.36 billion tons in China in 2018, the amount is expected to increase over the next few years. Dumping these wastes in sanitary landfills has always been the traditional approach to waste management but this will not be feasible in the years to come. To significantly reduce or eliminate the amount of CDW being dumped, circular economy is a possible solution to the increasing amounts of CDW. Circular economy is an economic system based on business models which replaces the end-of-life concept with reducing, reusing, recycling, and recovering materials. This paper discusses circular economy (CE) frameworks-specifically material recovery and production highlighting the reuse and recycling of CDW and reprocessing into new construction applications. Likewise, a literature review into recent studies of reuse and recycling of CDW and its feasibility is also discussed to possibly prove the effectivity of CE in reducing CDW. Findings such as effectivity of recycling CDW into new construction applications and its limitations in effective usage are discussed and research gaps such as reuse of construction materials are also undertaken. CE and recycling were also found to be emerging topics. Observed trends in published articles as well as the use of latent Dirichlet allocation in creating topic models have shown a rising awareness and increasing research in CE which focuses on recycling and reusing CDW.
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The zebrafish leopard phenotype (leo) displays abnormal pigmentation and shows increased anxiety-like behavior. The neurochemical changes associated with this anxious phenotype are not known. Here, we demonstrate that leo show increased anxiety-like behavior in the light/dark box and in the novel tank test. This anxious phenotype is rescued by acute treatment with a dose of a serotonin reuptake inhibitor, fluoxetine, that is inactive in wild-type animals. Moreover, leo show decreased tissue levels of serotonin, increased serotonin turnover and slightly increased monoamine oxidase activity. These results suggest that the anxious phenotype observed in leo zebrafish is caused by a decrease in serotonin uptake. This work could open an important avenue in defining the neurochemical underpinning of natural variation in anxiety disorders.
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Ansiedad/metabolismo , Serotonina/metabolismo , Pigmentación de la Piel/genética , Pez Cebra/fisiología , Animales , Ansiedad/genética , Fluoxetina/farmacología , Monoaminooxidasa/metabolismo , Actividad Motora/efectos de los fármacos , Mutación , Fenotipo , Inhibidores Selectivos de la Recaptación de Serotonina/farmacología , Pez Cebra/genética , Pez Cebra/metabolismoRESUMEN
AIM: With capsule endoscopy (CE) it is possible to examine the entire small bowel. The present study assessed the diagnostic yield of CE in severe obscure-overt gastrointestinal bleeding (OOGIB). METHODS: During a 3-year period, 15 capsule examinations (4.5% of all CE in a single institution) were carried out in 15 patients (11 men; mean age 69.9 +/- 20.1 years) with severe ongoing bleeding, defined as persistent melena and/or hematochezia, with hemodynamic instability and the need for significant red blood cell transfusion. CE was carried out after non-diagnostic standard upper and lower endoscopy. The mean time from admission until CE was 4.1 +/- 4.4 days (0-15 days). RESULTS: CE revealed active bleeding in seven patients and signs of recent bleeding in four. Etiology of bleeding was correctly diagnosed in 11 patients (73.3%) (portal hypertension enteropathy, three patients; subepithelial ulcerated lesion, two patients; angiodysplasia, two patients; jejunal ulcer with visible vessel, one patient; multiple small bowel ulcers, one patient; jejunal tumor, one patient; jejunal mucosa irregularity with adherent clot, one patient). One patient (6.7%) had active bleeding but no visible lesion. As a consequence of the capsule findings, specific therapeutic measures were undertaken in 11 patients (73.3%) with five managed conservatively, four endoscopically and two surgically. Two patients experienced bleeding recurrence. One of them, with a probable small bowel tumor, refused any other interventions. CONCLUSIONS: CE is useful in patients with severe OOGIB by providing positive findings in the majority of patients, with subsequent impact on therapeutic procedures.
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Endoscopía Capsular , Hemorragia Gastrointestinal/etiología , Anciano , Anciano de 80 o más Años , Endoscopía del Sistema Digestivo , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Small bowel pseudomelanosis is a rarely reported clinical entity characterized by brown pigmentation of small bowel mucosa. The authors describe two cases, both with iron deficiency anemia, one of an 81-year-old female patient submitted for capsule endoscopy that revealed a brown pigmentation of all small bowel mucosa and another of an 81-year-old male whose retrograde double-balloon enteroscopy revealed a diffuse brown pattern of small bowel mucosa. Ileal biopsies confirmed intense iron deposition in the macrophages of the lamina propria. Both patients were on oral iron therapy and the second one had a previous double-balloon enteroscopy, 2 years earlier, which revealed only ileal angiodysplasias. These two cases demonstrate the importance of two new endoscopic methods for diagnosis of small bowel pseudomelanosis, the rarity of such an entity and its close relation with oral iron therapy.
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Anemia Ferropénica/tratamiento farmacológico , Hematínicos/efectos adversos , Hiperpigmentación/inducido químicamente , Enfermedades Intestinales/inducido químicamente , Hierro/efectos adversos , Administración Oral , Anciano de 80 o más Años , Endoscopía Capsular , Endoscopía del Sistema Digestivo , Femenino , Hematínicos/administración & dosificación , Humanos , Intestino Delgado , Hierro/administración & dosificación , MasculinoRESUMEN
Small bowel tumors are rare, accounting for 1-2% of all gastrointestinal neoplasms. We sought to determine the diagnostic and therapeutic impact of double-balloon enteroscopy (DBE) in patients with small bowel tumors. Between January 2005 and March 2008, 78 patients underwent 96 DBE. All nine patients (seven males; mean age 68 +/- 11.3 years) with small bowel tumors were retrospectively reviewed. Clinical presentation was: mid-gastrointestinal bleeding or iron-deficient anemia (55.6%); abdominal pain (22.2%); nausea/vomiting and abdominal distension (22.2%). Five patients had abnormal findings in previous capsule endoscopy and four in previous radiologic examinations. Route of insertion was exclusively oral and abnormal lesions were detected in all patients (jejunum 8; ileum 1). Biopsies were taken in seven patients and provided definitive histological diagnosis in all except one. There were no complications of DBE. Surgical resection took place in eight patients. Final histologic diagnosis were: primary carcinoma (33.3%), gastrointestinal stromal tumor (GIST) (33.3%), malignant lymphoma (22.2%), and carcinoid tumor (11.1%). Mean follow-up time was 15.4 +/- 12.7 months (range 2-34 months). Six patients were submitted to chemotherapy. Two patients died. Small bowel tumors are common in patients submitted to DBE. Given its safety and diagnostic capabilities, DBE should be considered the gold-standard method in the study of these neoplasms.
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Neoplasias del Ciego/diagnóstico , Neoplasias del Yeyuno/diagnóstico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Endoscopía Capsular , Neoplasias del Ciego/complicaciones , Constricción Patológica , Femenino , Hemorragia Gastrointestinal/etiología , Humanos , Mucosa Intestinal/patología , Neoplasias del Yeyuno/complicaciones , Yeyuno/patología , Masculino , Persona de Mediana Edad , Portugal , Estudios Retrospectivos , Adulto JovenRESUMEN
Primary leiomyoma of the liver is an exceptionally rare tumour in non-immunocompromised patients. Preoperative diagnosis of the lesion is difficult as complete imaging of this type of lesion is scarcely defined and preoperative biopsy was not the practice in previously reported cases. We report a voluminous primary leiomyoma of the liver occurring in a healthy middle-aged woman where a preoperative diagnosis was accurately achieved on biopsy. Because of its size, surgery was undertaken for exclusion of malignancy. A 16-month uneventful follow-up has been completed. We discuss the advantage of a preoperative diagnosis and propose that an imaging-guided liver biopsy should be undertaken, provided malignancy features are absent. This could prevent liver surgery merely for diagnostic purposes. Finally, we report imaging features that have not been previously described, namely on magnetic resonance imaging, which may provide an insight about the nature of this particular lesion and, advantageously, contribute toward a non-invasive diagnosis.
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BACKGROUND AND AIM: The effects of portal hypertension in the small bowel are largely unknown. The aim of the study was to prospectively assess portal hypertension manifestations in the small bowel. METHODS: We compared, by performing enteroscopy with capsule endoscopy, the endoscopic findings of 36 patients with portal hypertension, 25 cirrhotic and 11 non-cirrhotic, with 30 controls. RESULTS: Varices, defined as distended, tortuous, or saccular veins, and areas of mucosa with a reticulate pattern were significantly more frequent in patients with PTH. These two findings were detected in 26 of the 66 patients (39%), 25 from the group with PTH (69%) and one from the control group (3%) (P < 0.0001). Among the 25 patients with PTH exhibiting these patterns, 17 were cirrhotic and 8 were non-cirrhotic (P = 0.551). The presence of these endoscopic changes was not related to age, gender, presence of cirrhosis, esophageal or gastric varices, portal hypertensive gastropathy, portal hypertensive colopathy, prior esophageal endoscopic treatment, current administration of beta-blockers, or Child-Pugh Class C. More patients with these endoscopic patterns had a previous history of acute digestive bleeding (72% vs. 36%) (P = 0.05). Active bleeding was found in two patients (5.5%). CONCLUSIONS: The presence of varices or areas of mucosa with a reticulate pattern are manifestations of portal hypertension in the small bowel, found in both cirrhotic and non-cirrhotic patients. The clinical implications of these findings, as regards digestive bleeding, are uncertain, although we documented acute bleeding from the small bowel in two patients (5.5%).