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INTRODUCTION AND AIM: Endoscopic retrograde cholangiopancreatography (ERCP) is a complex procedure. Clinical guidelines assess competence in ERCP through a defined number of procedures, but multiple factors are involved. Our aim was to analyze the morphology of the papilla of Vater as an independent factor in selective common bile duct cannulation during resident training. MATERIAL AND METHODS: Patients that underwent ERCP were studied consecutively. All ERCPs were begun by a resident in training. The type of papilla was classified according to Haraldsson, including those with previous sphincterotomy. Cannulation difficulty and success and their relation to the type of papilla were documented. The analysis was divided into three 4-month periods. RESULTS: Of the 429 patients, cannulation was difficult in 101 (23.5%). The residents achieved selective cannulation of the common bile duct in 276 (64.3%) and the cannulation success rate at the end of their training was 81.7%. Cannulation was performed with the least difficulty in papillae with previous sphincterotomy (2.8%), unlike the type 4 papilla, which was difficult to cannulate in 50% of the cases. The lowest overall cannulation success was in the type 2 papilla (81.8%). CONCLUSION: Papilla type can influence cannulation success, but it is not the only related factor. Patients that underwent previous sphincterotomy appear to be the cases in whom ERCP training can be started.
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INTRODUCTION: Neuromyelitis optica (NMO) is an inflammatory disease of the central nervous system characterised by attacks of optic neuritis and longitudinally extensive transverse myelitis. The discovery of anti-aquaporin-4 (anti-AQP4) antibodies and specific brain MRI findings as diagnostic biomarkers have enabled the recognition of a broader and more detailed clinical phenotype, known as neuromyelitis optica spectrum disorder (NMOSD). OBJECTIVE: This study aimed to determine the demographic and clinical characteristics of patients with NMO/NMOSD with and without seropositivity for anti-AQP4 antibodies, in 2 quaternary-level hospitals in Bogotá. METHODS: Our study included patients > 18 years of age and diagnosed with NMO/NMOSD and for whom imaging and serology results were available, assessed between 2013 and 2017 at the neurology departments of hospitals providing highly complex care. Demographic, clinical, and imaging data were gathered and compared in patients with and without seropositivity for anti-AQP4 antibodies. RESULTS: The sample included 35 patients with NMO/NMOSD; the median age of onset was 46.5 years (P25-P75, 34.2-54.0); most patients had sensory (n = 25) and motor manifestations (n = 26), and a concomitant autoimmune disease was identified in 6. Twenty patients were seropositive for anti-AQP4 antibodies. Only age and presence of optic nerve involvement showed statistically significant differences between groups (P = .03). CONCLUSIONS: Clinical, imaging, and laboratory variables showed no major differences between patients with and without anti-AQP4 antibodies, with the exception of age of onset and presence of optic nerve involvement (uni- or bilateral); these factors should be studied in greater detail in larger populations.
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Mielitis Transversa , Neuromielitis Óptica , Humanos , Persona de Mediana Edad , Neuromielitis Óptica/complicaciones , Colombia , Acuaporina 4 , AutoanticuerposRESUMEN
SARS-CoV-2 infection has been associated with multiple neurological manifestations. One such manifestation, which has been described since the early stages of the COVID-19 pandemic and is relevant for current neurological practice, is Guillain-Barré syndrome (GBS). The literature describes neurotoxic mechanisms of the virus itself and the possible pathways by which it may affect the peripheral nerves in experimental studies; however, we still lack information on the mechanisms causing the immune response that gives rise to GBS in the context of SARS-CoV-2 infection. Colombia is one of the Latin American countries worst affected by the pandemic, with the third-highest number of cases in the region; thus, it is essential to recognise GBS, as this potential postinfectious complication may severely compromise the patient's functional status in the absence of timely diagnosis and treatment. We present a series of 12 cases of GBS associated with SARS-CoV-2 infection from hospitals in 4 different Colombian cities and describe the clinical presentation, laboratory and electrophysiological study findings, and treatment.
En el año 2020 se declaro la pandemia ocasionada por la infección por el virus SARSCoV-2, virus de la familia del coronavirus, adoptándose el nombre de COVID-19 a la enfermedad 1. En Bogotá, Colombia, se confirmó el primer caso de COVID-19 el 6 de marzo de 2020 (2). Los principales síntomas reportados en la infección por SARSCoV-2 son fiebre (43.8% en la admisión y 88.7% durante la hospitalización) y tos (67.8%) (3). Otros síntomas encontrados son fatiga (38.1%), producción de esputo (33.7%) y cefalea (13.6%). Los principales signos neurológicos reportados en los pacientes con infección severa por SARS-Cov-2 son agitación (69%), compromiso en tracto corticoespinal (67%) y delirium (65%) (4). Las principales complicaciones neurológicas descritas asociadas a Covid 19 son: anosmia, disgeusia, encefalopatia, Síndrome de Guillain Barre, complicaciones cerebrovasculares y daño en musculo esquelético (58).En el presente articulo se presenta una serie de casos de pacientes con síndrome de Guillain-Barré asociado a infección por SARS-CoV-2. Se recolectaron casos de diferentes instituciones medicas de Colombia.
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"Serrated polyps" is the term used for epithelial lesions of the colon and rectum that have a "sawtooth" pattern on the polyp's surface and crypt epithelium. The so-called serrated pathway describes the progression of sessile serrated adenomas and traditional serrated adenomas to colorectal cancer. Said pathway is well recognized as an alternative mechanism of carcinogenesis and accounts for 15-30% of the cases of colorectal cancer. It also explains a large number of the cases of interval colorectal cancer. Thus, due to their usually aggressive and uncertain behavior, serrated polyps are of the utmost importance in colorectal cancer screening. Our aim was to review the history, current nomenclature, pathophysiology, morphology, treatment, and surveillance of serrated polyps.
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Adenoma , Pólipos del Colon , Neoplasias Colorrectales , Adenoma/patología , Pólipos del Colon/patología , Neoplasias Colorrectales/diagnóstico , Humanos , Recto/patologíaRESUMEN
INTRODUCTION: Neuromyelitis optica (NMO) is an inflammatory disease of the central nervous system characterised by attacks of optic neuritis and longitudinally extensive transverse myelitis. The discovery of anti-aquaporin-4 (anti-AQP4) antibodies and specific brain MRI findings as diagnostic biomarkers have enabled the recognition of a broader and more detailed clinical phenotype, known as neuromyelitis optica spectrum disorder (NMOSD). OBJECTIVE: This study aimed to determine the demographic and clinical characteristics of patients with NMO/NMOSD with and without seropositivity for anti-AQP4 antibodies, in 2 quaternary-level hospitals in Bogotá. METHODS: Our study included patients > 18 years of age and diagnosed with NMO/NMOSD and for whom imaging and serology results were available, assessed between 2013 and 2017 at the neurology departments of hospitals providing highly complex care. Demographic, clinical, and imaging data were gathered and compared in patients with and without seropositivity for anti-AQP4 antibodies. RESULTS: The sample included 35 patients with NMO/NMOSD; the median age of onset was 46.5 years (P25-P75, 34.2-54.0); most patients had sensory (n = 25) and motor manifestations (n = 26), and a concomitant autoimmune disease was identified in 6. Twenty patients were seropositive for anti-AQP4 antibodies. Only age and presence of optic nerve involvement showed statistically significant differences between groups (p = .03). CONCLUSIONS: Clinical, imaging, and laboratory variables showed no major differences between patients with and without anti-AQP4 antibodies, with the exception of age of onset and presence of optic nerve involvement (uni- or bilateral); these factors should be studied in greater detail in larger populations.
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More than 30 million persons worldwide take nonsteroidal anti-inflammatory drugs (NSAIDs) on a daily basis, and annual consumption is increasing. In addition to their analgesic and anti-inflammatory properties, NSAIDs also produce well-known gastrointestinal adverse events. There is no consensus in Mexico on the diagnosis, treatment, and prevention of NSAID-induced gastropathy and enteropathy, and so the Asociación Mexicana de Gastroenterología brought together a group of experts to establish useful recommendations for the medical community. Thirty-three recommendations were formulated in the present consensus, highlighting the fact that the risk for NSAID-induced gastrointestinal toxicity varies according to the drug employed and its pharmacokinetics, which should be taken into account at the time of prescription. The risk factors for gastroduodenal complications due to NSAIDs are: a history of peptic ulcer, age above 65 years, high doses of NSAIDs, Helicobacter pylori infection, and the presence of severe comorbidities. The symptoms and gastroduodenal damage induced by NSAIDs vary, ranging from an asymptomatic course to the presentation of iron-deficiency anemia, bleeding, stricture, and perforation. Capsule endoscopy and enteroscopy are direct diagnostic methods in NSAID enteropathy. Regarding prevention, the minimum dose of an NSAID needed to achieve the desired effect, administered for the shortest period of time, is the recommendation. Finally, proton pump inhibitors are the gold standard for the prophylaxis and treatment of gastroduodenal effects, but they are not useful in enteropathy.
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Antiinflamatorios no Esteroideos/efectos adversos , Enfermedades Gastrointestinales/inducido químicamente , Factores de Edad , Endoscopía Gastrointestinal , Enfermedades Gastrointestinales/diagnóstico , Enfermedades Gastrointestinales/terapia , Humanos , México , Factores de RiesgoRESUMEN
RESUMEN: El correcto sellado apical es un paso importante durante el tratamiento de conductos, para esto, se utilizan puntas de gutapercha y cemento sellador, de este último existen diversas formulaciones químicas en el mercado, por lo cual es importante tomar en cuenta los efectos que estas pueden tener en el proceso de cicatrización periapical. El propósito de este estudio fue evaluar la biocompatibilidad de cuatro cementos selladores con diferente composición química con osteoblastos humanos. Se prepararon extractos de cementos selladores a con dos concentraciones (10 mg/mL y 40 mg/mL) y dos tiempos de exposición (10 min y 8 h), estos fueron colocados en contacto con osteoblastos humanos para evaluar la proliferación y citotoxicidad a 24, 72 y 96 h con sus respectivos controles y blancos. Se realizó un análisis estadístico con ANOVA de un factor y la prueba de comparaciones múltiple de Bonferroni. Los resultados obtenidos, tanto en el ensayo de citotoxicidad como en el de proliferación, indicaron que el cemento a base de resina no es biocompatible con osteoblastos. El cemento a base de poli-dimetilxilosano fue el único que no mostró citotoxicidad a ningún de tiempo de exposición y concentración examinadas en este estudio.
ABSTRACT: Correct apical sealing is an important step during root canal treatment, hence, gutta-percha points and sealant are used. There are several chemical compositions on the market, so it is important to evaluate the effects of these in the periapical healing process. The aim of this study was to evaluate the biocompatibility of four sealer cements with different chemical composition placed in contact with human osteoblast. Different extracts were prepared at two concentrations (10 mg/mL and 40 mg/mL) and two exposure times (10 min and 8 h) these were placed in contact with human osteoblast to evaluate cytotoxicity and proliferation at 24, 48 and 72 h with their respective controls and blanks. A statistical analysis was performed with ANOVA of one factor and Bonferroni post hoc. Results obtained in cytotoxicity and proliferation assays, indicated that the resinbased cement is not biocompatible with osteoblast. The poly-dimethylxilosanbased cement was the only that did not show cytotoxicity at any time of exposure and concentration examined in this study.
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Humanos , Osteoblastos , Ensayo de Materiales/métodos , Cementos Dentales/química , Técnicas In Vitro , Análisis de VarianzaRESUMEN
Objetivo: Exponer nuestra experiencia y evaluar la recurrencia en el manejo quirúrgico del angiofibroma nasal juvenil, abordaje abierto contra endoscópico, en el servicio de otorrinolaringología del noroeste del país. Materiales y métodos: Estudio observacional, retrospectivo, analítico. Se revisaron los expedientes clínicos de los pacientes con diagnóstico de angiofibroma nasal juvenil de 2014 a 2017, atendidos en el Servicio de Otorrinolaringología y Cirugía de Cabeza y Cuello de esta institución. Resultados: Un total de 19 pacientes con diagnóstico de angiofibroma nasal juvenil, fueron sometidos a un procedimiento quirúrgico, 14 abiertos y 5 endoscópicos, la recurrencia fue de 50 % y 40 % respectivamente, lo cual no fue estadísticamente significativo (p=0.88). No obstante, se contrastaron otras variables, como la necesidad de la Unidad de Cuidados Intensivos (UCI) para ambos grupos, 71 % en abordaje abierto y 20 % para el endoscópico, en lo cual si encontramos diferencia significativa (p=0.04). Conclusiones: El estudio no muestra una ventaja estadísticamente significativa del abordaje endoscópico frente al abordaje abierto, pero sí una menor necesidad de hospitalización en UCI, lo que reduciría los costos de atención.
Objective: To present our experience and assess the recurrence of juvenile nasopharyngeal angiofibroma after a surgical treatment (open versus endoscopic approach) in the country's northwestern Department of Otorhinolaryngology. Materials and methods: An observational, retrospective, analytical study. The medical records of patients diagnosed with juvenile nasopharyngeal angiofibroma, who were treated at the Department of Otorhinolaryngology - Head and Neck Surgery of this institution from 2014 to 2017, were reviewed. Results: A total of 19 patients diagnosed with juvenile nasopharyngeal angiofibroma underwent a surgical procedure, out of which 14 had an open surgery and 5 an endoscopic one. Recurrence accounted for 50 % and 40 %, respectively, which was not statistically significant (p = 0.88). However, other variables were compared, such as the need for admission to the Intensive Care Unit (ICU), which was represented by 71 % in the case of the open approach and 20 % for the endoscopic approach, where a significant difference was found (p = 0.04). Conclusions: The study shows no statistically significant advantage of the endoscopic approach versus the open approach, but demonstrates less need for ICU admissions, which would reduce healthcare costs.
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The measurement of local temperature in nanoscale volumes is becoming a technological frontier. Photoluminescent nanoparticles and nanocolloids are the natural choice for nanoscale temperature probes. However, the influence of a surrounding liquid on the cryogenic behavior of oxidized Si-nanocrystals (Si-NCs) has never been investigated. In this work, the photoluminescence (PL) of oxidized Si-NCs/alcohol based nanocolloids is measured as a function of the temperature and the molecule length of monohydric alcohols above their melting-freezing point. The results unveil a progressive blue shift on the emission peak which is dependent on the temperature as well as the dielectric properties of the surrounding liquid. Such an effect is analyzed in terms of thermal changes of the Si-NCs bandgap, quantum confinement and the polarization effects of the embedding medium; revealing an important role of the dielectric constant of the surrounding liquid. These results are relevant because they offer a general insight to the fundamental behavior of photoluminescent nanocolloids under a cooling process and moreover, enabling PL tuning based on the dielectric properties of the surrounding liquid. Hence, the variables required to engineer PL of nanofluids are properly identified for use as temperature sensors at the nanoscale.
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Glucose-6-phosphate dehydrogenase deficiency (G6PD) is the most common enzyme pathology in humans; it is X-linked inherited and causes neonatal hyperbilirubinaemia, chronic nonspherocytic haemolytic anaemia and drug-induced acute haemolytic anaemia. G6PD deficiency has scarcely been studied in the northern region of Mexico, which is important because of the genetic heterogeneity described in Mexican population. Therefore, samples from the northern Mexico were biochemically screened for G6PD deficiency, and PCR-RFLPs, and DNA sequencing used to identify mutations in positive samples. The frequency of G6PD deficiency in the population was 0.95% (n = 1993); the mutations in 86% of these samples were G6PD A(-202A/376G), G6PDA(-376G/968C) and G6PD Santamaria(376G/542T). Contrary to previous reports, we demonstrated that G6PD deficiency distribution is relatively homogenous throughout the country (P = 0.48336), and the unique exception with high frequency of G6PD deficiency does not involve a coastal population (Chihuahua: 2.4%). Analysis of eight polymorphic sites showed only 10 haplotypes. In one individual we identified a new G6PD mutation named Mexico DF(193A>G) (rs199474830), which probably results in a damaging functional effect, according to PolyPhen analysis. Proteomic impact of the mutation is also described.
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Deficiencia de Glucosafosfato Deshidrogenasa/genética , Glucosafosfato Deshidrogenasa/genética , Mutación Missense , Análisis Mutacional de ADN , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Glucosafosfato Deshidrogenasa/química , Deficiencia de Glucosafosfato Deshidrogenasa/epidemiología , Haplotipos , Humanos , Masculino , México/epidemiología , Modelos Moleculares , Polimorfismo de Longitud del Fragmento de Restricción , Estructura Terciaria de ProteínaAsunto(s)
Endoscopía Capsular , Hemorragia Gastrointestinal/diagnóstico , Hemorragia Gastrointestinal/etiología , Infecciones por Uncinaria/complicaciones , Adulto , Animales , Femenino , Hemorragia Gastrointestinal/parasitología , Infecciones por Uncinaria/parasitología , Humanos , Intestino Delgado/parasitología , Necator americanusRESUMEN
Determining the diagnosis of Crohn's disease has been highly difficult mainly during the first years of this study carried out at the Pontificia Universidad Catolica (PUC) Clinical Hospital. For instance, it has been frequently confused with Irritable bowel syndrome and sometimes misdiagnosed as ulcerative colitis, infectious colitis or enterocolitis, intestinal lymphoma, or coeliac disease. Consequently, it seems advisable to characterize what the most relevant clinical features are, in order to establish a clear concept of Crohn's disease. This difficulty may still be a problem at other medical centers in developing countries. Thus, sharing this information may contribute to a better understanding of this disease. Based on the clinical experience gained between 1963 and 2004 and reported herein, the main clinical characteristics of the disease are long-lasting day and night abdominal pain, which becomes more intense after eating and diarrhoea, sometimes associated to a mass in the abdomen, anal lesions, and other additional digestive and nondigestive clinical features. Nevertheless, the main aim of this work has been the following: is it possible to make, in an early stage, the diagnosis of Crohn's disease with a high degree of certainty exclusively with clinical data?
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The antiplasmodial activity of phospholipases A(2) (PLA(2)) isolated from different animals has been studied. We explored the in vitro anti Plasmodium falciparum effect of a fraction containing crotoxin, Crotoxin B and whole venom of the rattlesnake Crotalus durissus cumanensis. Fraction II (crotoxin complex) was obtained by size exclusion chromatography, whereas Crotoxin B was purified by RP-HPLC. The whole venom is active against the parasite at concentrations of 0.17±0.03 µg/ml, fraction II at 0.76±0.17 µg/ml and Crotoxin B at 0.6±0.04 µg/ml. Differences were observed in the cytotoxic activity against peripheral mononuclear cells, with Crotoxin B exhibiting the highest cytotoxicity. The concentration of Crotoxin B required to exert cytotoxic activity was higher than that required to exert antiplasmodial activity. Lethality in mice confirmed the higher toxicity and neurotoxicity of whole venom and fraction II, whereas Crotoxin B was not lethal at the doses tested. These results suggest the potential of Crotoxin B as a lead compound for antimalarial activity.
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Antimaláricos/farmacología , Crotalus/metabolismo , Crotoxina/farmacología , Plasmodium falciparum/efectos de los fármacos , Ponzoñas/farmacología , Secuencia de Aminoácidos , Animales , Antimaláricos/aislamiento & purificación , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Crotoxina/aislamiento & purificación , Humanos , Leucocitos Mononucleares/efectos de los fármacos , Ratones , Datos de Secuencia Molecular , Análisis de Supervivencia , Ponzoñas/aislamiento & purificaciónRESUMEN
Non-functioning pancreatic neuroendocrine tumors (PNETs) are infrequent slow-growing, clinically-silent tumors. They are incidentally detected and some of them may present in advanced stages with local involvement of surrounding structures. The diagnostic accuracy of endoscopio ultrasound (EUS) and fine needle aspiration (FNA) biopsy is significantly lower in neuroendocrine tumors (46.7%) compared with adenocarcinoma (81.4%) and other histologies (75%). Therefore, preoperative diagnosis is very difficult. Exceptionally, hey present with gastrointestinal bleeding. We present a case of a non-functioning PNET initially diagnosed as cystic serous tumor of pancreas with EUS and FNA biopsy. Two years later patient presented obscure gastrointestinal bleeding due to duodenal infiltration. Diagnosis was made by capsule endoscopy.
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Endoscopía Capsular , Neoplasias Duodenales/complicaciones , Hemorragia Gastrointestinal/diagnóstico , Hemorragia Gastrointestinal/etiología , Neoplasias Pancreáticas/complicaciones , Femenino , Humanos , Persona de Mediana Edad , Invasividad Neoplásica , Neoplasias Pancreáticas/patologíaRESUMEN
Introducción. La Fluor-18 deoxiglucosa (18F-FDG) ha sido utilizada en múltiples estudios para determinar la tasa de utilización de la glucosa en condiciones normales y patológicas. Actualmente se sabe que en la insuficiencia cardiaca el patrón metabólico se encuentra alterado. Materiales y métodos Se realizó medición del metabolismo glucocídico en 4 portadores de miocardiopatía dilatada y en 3 sujetos sanos, todos bajo una carga de hidratos de carbono vía oral (75gr). Se adquirieron imágenes dinámicas de tórax. La captación miocárdica se estimó a partir de las curvas tiempo-actividad en aurícula y ventrículo izquierdo utilizando el análisis gráfico de Patlak. Resultados. Los siete pacientes estudiados son de sexo masculino. La tasa de captación de la 18F-FDG para el grupo de pacientes con miocardiopatía dilatada fue 1,31 +/- 0,2 versus 1,26 +/- 0,37 ml/100gr/min en el grupo control. Conclusión. La medición del metabolismo cardiaco de la glucosa por medio de 18F-FDG PET es posible de realizar en un servicio clínico, permitiendo de esta forma determinar la repercusión fisiológica y los cambios del metabolismo miocárdico en diversas enfermedades además de la evaluación de terapia.
Introduction. Fluorine18 deoxyglucose (18F-FDG) has been used in numerous studies to determine the cardiac rate of glucose metabolism in normal and pathological conditions. It is known that during heart failure the metabolic pattern is altered. Patlacks graphical analysis allows the assessment of heart muscle glucose consumption in patients with non-ischaemic heart failure and normal subjects. Methods. Standardized measurement of glucose metabolism was performed in four patients with dilated cardiomyopathy and three healthy subjects. All subjects received an oral load of carbohydrates (75gr) previous to scanning. Dynamic images of the thorax were acquired. Myocardial uptake was estimated from time-activity curves in the atrium and left ventricle using Patlacks graphical analysis. Results. All subjects studied were male. 18F-FDG uptake rate for the group with dilated cardiomyopathy was 1.31 +/-0.2, versus 1.26 +/- 0.37 ml/100gr/min in the control group. Conclusion. Measurement of cardiac glucose metabolism by 18F-FDG PET is feasible in a clinical service, allowing impact evaluation of physiologic and metabolic changes in the myocardium in different pathologic scenarios in addition to therapy assessment.
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Humanos , Masculino , Adulto , Persona de Mediana Edad , Cardiomiopatía Dilatada , Cardiomiopatía Dilatada/metabolismo , /farmacocinética , Glucosa/metabolismo , Tomografía de Emisión de Positrones , Miocardio/metabolismo , Radiofármacos/farmacocinéticaRESUMEN
A new irradiation facility has been developed in the RA-3 reactor in order to perform trials for the treatment of liver metastases using boron neutron capture therapy (BNCT). RA-3 is a production research reactor that works continuously five days a week. It had a thermal column with a small cross section access tunnel that was not accessible during operation. The objective of the work was to perform the necessary modifications to obtain a facility for irradiating a portion of the human liver. This irradiation facility must be operated without disrupting the normal reactor schedule and requires a highly thermalized neutron spectrum, a thermal flux of around 10(10) n cm(-2)s(-1) that is as isotropic and uniform as possible, as well as on-line instrumentation. The main modifications consist of enlarging the access tunnel inside the thermal column to the suitable dimensions, reducing the gamma dose rate at the irradiation position, and constructing properly shielded entrance gates enabled by logical control to safely irradiate and withdraw samples with the reactor at full power. Activation foils and a neutron shielded graphite ionization chamber were used for a preliminary in-air characterization of the irradiation site. The constructed facility is very practical and easy to use. Operational authorization was obtained from radioprotection personnel after confirming radiation levels did not significantly increase after the modification. A highly thermalized and homogenous irradiation field was obtained. Measurements in the empty cavity showed a thermal flux near 10(10) n cm(-2)s(-1), a cadmium ratio of 4100 for gold foils and a gamma dose rate of approximately 5 Gy h(-1).
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Terapia por Captura de Neutrón de Boro/instrumentación , Reactores Nucleares , Animales , Arquitectura y Construcción de Instituciones de Salud , Neutrones Rápidos/uso terapéutico , Humanos , Neoplasias Hepáticas/radioterapia , Neoplasias Hepáticas/secundario , Protección Radiológica/instrumentaciónRESUMEN
The National Atomic Energy Commission of Argentina (CNEA) constructed a novel thermal neutron source for use in boron neutron capture therapy (BNCT) applications at the RA-3 research reactor facility located in Buenos Aires. The aim of the present study was to perform a dosimetric characterization of the facility and undertake radiobiological studies of BNCT in an experimental model of oral cancer in the hamster cheek pouch. The free-field thermal flux was 7.1 x 10(9) n cm(-2)s(-1) and the fast neutron flux was 2.5 x 10(6) n cm(-2)s(-1), indicating a very well-thermalized neutron field with negligible fast neutron dose. For radiobiological studies it was necessary to shield the body of the hamster from the neutron flux while exposing the everted cheek pouch bearing the tumors. To that end we developed a lithium (enriched to 95% in (6)Li) carbonate enclosure. Groups of tumor-bearing hamsters were submitted to BPA-BNCT, GB-10-BNCT, (GB-10+BPA)-BNCT or beam only treatments. Normal (non-cancerized) hamsters were treated similarly to evaluate normal tissue radiotoxicity. The total physical dose delivered to tumor with the BNCT treatments ranged from 6 to 8.5 Gy. Tumor control at 30 days ranged from 73% to 85%, with no normal tissue radiotoxicity. Significant but reversible mucositis in precancerous tissue surrounding tumors was associated to BPA-BNCT. The therapeutic success of different BNCT protocols in treating experimental oral cancer at this novel facility was unequivocally demonstrated.
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Terapia por Captura de Neutrón de Boro/instrumentación , Neoplasias de la Boca/radioterapia , Reactores Nucleares , 9,10-Dimetil-1,2-benzantraceno/toxicidad , Animales , Argentina , Terapia por Captura de Neutrón de Boro/efectos adversos , Terapia por Captura de Neutrón de Boro/métodos , Carcinógenos/toxicidad , Cricetinae , Mesocricetus , Neoplasias de la Boca/inducido químicamente , Radiometría/métodosRESUMEN
The "left ventricular mass" (LVM) using Tc-99m Sestamibi SPECT imaging may be a useful parameter to quantitatively assess the left ventricle and hence its function. The LVM was determined without reorienting the images along the long axis of the left ventricle. A comparison with reoriented SPECT images was then performed. The LVM showed the expected variations among different pathological heart conditions and the control subjects. The left ventricular mass obtained from non-reoriented tomographic views of the myocardium can be a useful index to quantitatively assess various heart conditions where the myocardium lacks perfusion either between rest and stress studies or similar conditions in longitudinal studies.
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Inteligencia Artificial , Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Reconocimiento de Normas Patrones Automatizadas/métodos , Tecnecio Tc 99m Sestamibi , Tomografía Computarizada de Emisión de Fotón Único/métodos , Disfunción Ventricular Izquierda/diagnóstico por imagen , Anciano , Anciano de 80 o más Años , Algoritmos , Femenino , Humanos , Aumento de la Imagen/métodos , Masculino , Persona de Mediana Edad , Radiofármacos , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
INTRODUCTION AND OBJECTIVES: The correct interpretation of myocardial perfusion single photon emission computed tomography (SPECT) requires knowledge of the technique reproducibility. The objective was analyze the interobserver correlation of different experience in the interpretation of myocardial perfusion SPECT in patients following acute myocardial infarction (AMI) in order to improve the quality of our site. METHODS: Sixty cases (56 +/- 11 years, 87 % men) with transmural AMI who had recently undergone successful thrombolysis were included. Resting perfusion with (99m)Tc-sestamibi was performed at one week post-AMI. ANALYSIS: Semiquantitative interpretation using 17 segment-model by 2 independent specialists and 5 observers, was performed blindly. Left ventricular ejection fraction (LVEF) was measured with isotopic ventriculography one month after AMI, with a mean of 38 %. RESULTS: Using independent and then agreed on perfusion analysis, average involved segments/patient was 9.3 +/- 4 and the sum of severity 25 +/- 13. Readings of other observers ranged from 7 +/- 3.7 to 9.4 +/- 3.9 and 16.7 +/- 9.7 to 24.6 +/- 13, respectively, consistent with the reading of the specialists of between 0.779-0.871 (kappa: 0.565-0.741). There was no significant difference when the number of segments were analyzed in 40 % of the cases and for intensity in 60 % of them in more experienced observers. Correlation with consensus reading for the number of segments ranged from 0.84 to 0.94 and for severity from 0.79 to 0.89. Identification of culprit arteries was acceptable, with r values between 0.612 and 0.683 and kappas between 0.629 and 0.656. Correlation of the number of involved segments and severity with LVEF performed one month after AMI was 0.73 and 0.74, respectively. CONCLUSIONS: There was good correlation in the interpretation of myocardial perfusion SPECT, with a significantly better fit in more experienced observers. This academic exercise was also helpful in improving our residents' skills in cardiology.
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Infarto del Miocardio/diagnóstico por imagen , Infarto del Miocardio/cirugía , Radiofármacos , Tecnecio Tc 99m Sestamibi , Tomografía Computarizada de Emisión de Fotón Único , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reperfusión Miocárdica , Variaciones Dependientes del ObservadorRESUMEN
Image data fusion has been developed over the last decade as an important additional visual diagnostic tool to integrate the growing amount of imaging data obtained from different medical imaging modalities. The overwhelming amount of digital information calls for data consolidation to improve clinical treatment strategies based upon anatomical and physiological imaging. Three different low level image data fusion techniques are described and their characteristics are illustrated with some rare yet key examples. We used MR images to show neurodegeneration in the cerebral peduncle of the midbrain and found that image data fusion using colors can be a valuable tool to visually assess and quantify the loss of neural cells in the Substantia Nigra pars compacta in Parkinson's disease.