Na+/K+-ATPase: More than an Electrogenic Pump.

The sodium pump, or Na+/K+-ATPase (NKA), is an essential enzyme found in the plasma membrane of all animal cells. Its primary role is to transport sodium (Na+) and potassium (K+) ions across the cell membrane, using energy from ATP hydrolysis. This transport creates and maintains an electrochemical gradient, which is crucial for various cellular processes, including cell volume regulation, electrical excitability, and secondary active transport. Although the role of NKA as a pump was discovered and demonstrated several decades ago, it remains the subject of intense research. Current studies aim to delve deeper into several aspects of this molecular entity, such as describing its structure and mode of operation in atomic detail, understanding its molecular and functional diversity, and examining the consequences of its malfunction due to structural alterations. Additionally, researchers are investigating the effects of various substances that amplify or decrease its pumping activity. Beyond its role as a pump, growing evidence indicates that in various cell types, NKA also functions as a receptor for cardiac glycosides like ouabain. This receptor activity triggers the activation of various signaling pathways, producing significant morphological and physiological effects. In this report, we present the results of a comprehensive review of the most outstanding studies of the past five years. We highlight the progress made regarding this new concept of NKA and the various cardiac glycosides that influence it. Furthermore, we emphasize NKA's role in epithelial physiology, particularly its function as a receptor for cardiac glycosides that trigger intracellular signals regulating cell-cell contacts, proliferation, differentiation, and adhesion. We also analyze the role of NKA ß-subunits as cell adhesion molecules in glia and epithelial cells.

Effect of High Sodium Intake on Gut Tight Junctions' Structure and Permeability to Bacterial Toxins in a Rat Model of Chronic Kidney Disease.

INTRODUCTION: Uremic toxicity changes the gut structure and permeability, allowing bacterial toxins to translocate from the lumen to the blood during chronic kidney failure (CKD). Clinical fluid overload and tissue edema without uremia have similar effects but have not been adequately demonstrated and analyzed in CKD. AIMS: To investigate the effect of sodium intake on the plasma concentration of gut-derived uremic toxins, indoxyl sulfate (IS), and p-cresyl sulfate (pCS) and the expression of genes and proteins of epithelial gut tight junctions in a rat model of CKD. METHODS: Sham-operated (control group, CG) and five-sixths nephrectomized (5/6Nx) Sprague-Dawley rats were randomly assigned to low (LNa), normal (NNa), or high sodium (HNa) diets., Animals were then sacrificed at 8 and 12 weeks and analyzed for IS and pCS plasma concentrations, as well as for gene and protein expression of thigh junction proteins, and transmission electron microscopy (TEM) in colon fragments. RESULTS: The HNa 5/6Nx groups had higher concentrations of IS and pCS than CG, NNa, and LNa at eight and twelve weeks. Furthermore, HNa 5/6Nx groups had reduced expression of the claudin-4 gene and protein than CG, NNa, and LNa. HNa had reduced occludin gene expression compared to CG. Occludin protein expression was more reduced in HNa than in CG, NNa, and LNa. The gut epithelial tight junctions appear dilated in HNa compared to NNa and LNa in TEM. CONCLUSION: Dietary sodium intake and fluid overload have a significant role in gut epithelial permeability in the CKD model.

Extracellular Vesicles Secreted by Acanthamoeba culbertsoni Have COX and Proteolytic Activity and Induce Hemolysis.

Several species of Acanthamoeba genus are potential pathogens and etiological agents of several diseases. The pathogenic mechanisms carried out by these amoebae in different target tissues have been documented, evidencing the relevant role of contact-dependent mechanisms. With the purpose of describing the pathogenic processes carried out by these protozoans more precisely, we considered it important to determine the emission of extracellular vesicles (EVs) as part of the contact-independent pathogenicity mechanisms of A. culbertsoni, a highly pathogenic strain. Through transmission electronic microscopy (TEM) and nanoparticle tracking analysis (NTA), EVs were characterized. EVs showed lipid membrane and a size between 60 and 855 nm. The secretion of large vesicles was corroborated by confocal and TEM microscopy. The SDS-PAGE of EVs showed proteins of 45 to 200 kDa. Antigenic recognition was determined by Western Blot, and the internalization of EVs by trophozoites was observed through Dil-labeled EVs. In addition, some EVs biological characteristics were determined, such as proteolytic, hemolytic and COX activity. Furthermore, we highlighted the presence of leishmanolysin in trophozites and EVs. These results suggest that EVs are part of a contact-independent mechanism, which, together with contact-dependent ones, allow for a better understanding of the pathogenicity carried out by Acanthamoeba culbertsoni.

Clinical and Endoscopic Characterization of Gastrointestinal Kaposi's Sarcoma in an Institution in Southwestern Colombia between 2011 and 2020

Kaposi's sarcoma is an angioproliferative neoplasm associated with the human herpesvirus 8. According to the clinical characteristics and the degree of immunosuppression, there are four epidemiological forms: classic, endemic, iatrogenic, and epidemic. The latter is associated with acquired immunodeficiency syndrome (AIDS) and 40% GI involvement. There is little epidemiological, clinical, and endoscopic evidence of the disease. This study sought to characterize this condition in a Colombian population and compare the findings with publications from other countries. One hundred thirty-five records of patients who consulted between 2011 and 2020 for Kaposi's sarcoma were reviewed, of which 24 had GI involvement. Epidemiological, clinical, endoscopic, and treatment characteristics were obtained. Twenty-two patients were men. There were 21 patients infected with human immunodeficiency virus (HIV; 87.5%) and 19 receiving antiretroviral therapy (90%); 33.3% had HIV viral load > 100,000 copies/mL. The CD4+ count was <50 cells/µL in 28.6% of cases, between 50 and 100 cells/µL in 19.0%, and between 100 and 200 cells/µL in 14.4%. The rate of infection by other opportunistic infections was 41.7%. There were GI symptoms in 33% of the patients, and the most frequent were hematochezia, abdominal pain, nausea, and diarrhea. Most had concomitant skin lesions (70.8%). GI lesions were located mainly in the oropharynx (41.7%), stomach (20.8%), and colon (16.7%). The most common endoscopic finding was maculopapular erythema. This article provided insight into the local epidemiology of gastrointestinal Kaposi's sarcoma. In contrast to studies in other populations, GI symptoms were more frequent in this one, and there was a difference in endoscopic findings. Studies with larger populations are needed.

El sarcoma de Kaposi es una neoplasia angioproliferativa asociada al virus del herpes humano 8. Según las características clínicas y el grado de inmunosupresión, son cuatro las formas epidemiológicas: clásica, endémica, iatrogénica y epidémica, esta última asociada al síndrome de inmunodeficiencia adquirida (SIDA) y con un 40% de compromiso gastrointestinal. Existe escasa evidencia epidemiológica, clínica y endoscópica de la enfermedad. Este estudio buscó caracterizar esta condición en una población colombiana y contrastar los hallazgos con publicaciones de otros países. Se revisaron 135 registros de pacientes que consultaron entre el 2011 y 2020 por sarcoma de Kaposi, de los cuales 24 tenían compromiso gastrointestinal. Se obtuvieron características epidemiológicas, clínicas, endoscópicas y tratamientos. Veintidós pacientes eran hombres. Hubo 21 pacientes infectados por virus de la inmunodeficiencia humana (VIH; 87,5%) y 19 recibían terapia antirretroviral (90%). El 33,3% tenía carga viral VIH > 100 000 copias/mL. El recuento de CD4+ fue < 50 cel/µL en el 28,6% de los casos, entre 50 y 100 cel/µL en el 19,0%, y entre 100 y 200 cel/µL en el 14,4%. La tasa de infecciones por otros oportunistas fue de 41,7%. Hubo síntomas gastrointestinales en el 33% de los pacientes y los más frecuentes fueron hematoquecia, dolor abdominal, náuseas y diarrea. La mayoría tuvo lesiones cutáneas concomitantes (70,8%). Las lesiones gastrointestinales se localizaron principalmente en la orofaringe (41,7%), estómago (20,8%) y colon (16,7%). El hallazgo endoscópico más común fue eritema maculopapular. Este artículo mostró una visión de la epidemiología local del sarcoma de Kaposi gastrointestinal. En contraste con estudios en otras poblaciones, en este, los síntomas gastrointestinales fueron más frecuentes y hubo diferencia en los hallazgos endoscópicos. Son necesarios estudios con poblaciones más grandes.

Prevalencia de Helicobacter pylori en pacientes llevados a endoscopia de vías digestivas altas en un hospital de referencia en Cali, Colombia, en 2020 / Prevalence of Helicobacter pylori in patients undergoing upper digestive tract endoscopy at a referral hospital in Cali, Colombia, in 2020

Resumen Introducción: la infección por Helicobacter pylori tiene una alta prevalencia y distribución a nivel mundial. Por su asociación con el desarrollo de adenocarcinoma gástrico, las actualizaciones sobre su prevalencia son de interés para el médico internista o gastroenterólogo, así como para la generación de políticas públicas. Este estudio midió la prevalencia de H. pylori y evaluó su asociación con hallazgos endoscópicos e histopatológicos en adultos con indicación de endoscopia de vías digestivas altas (EVDA). Metodología: estudio de cohorte analítica para describir la prevalencia de H. pylori y evaluar factores de riesgo asociados a esta infección en pacientes adultos sometidos a EVDA ambulatoria por cualquier indicación médica en la unidad de endoscopia de un hospital universitario de cuarto nivel de complejidad entre junio y diciembre de 2020. Se describen hallazgos endoscópicos, histopatológicos y la prevalencia de H. pylori. Para explorar los factores de riesgo se usó la prueba chi cuadrado (χ2) para evaluar diferencias en las proporciones y las pruebas t de Student y U de Mann-Whitney para las variables continuas según su distribución. Resultados: 613 pacientes cumplieron los criterios de selección y fueron incluidos en el análisis. La indicación más frecuente de EVDA fue dispepsia. La prevalencia de H. pylori fue de 38,5% (intervalo de confianza [IC] 95%: 34,7%-42,4%). Conclusión: H. pylori es un tema de gran interés en las patologías gastrointestinales. La búsqueda endoscópica debe ser en el antro y cuerpo. Su presencia fue mayor en pacientes con esófago normal, gastritis nodular folicular, úlcera duodenal e inflamación aguda al estudio histológico. Se requieren más estudios que complementen el comportamiento epidemiológico local.

Abstract Introduction: Helicobacter pylori infection has a high prevalence and distribution worldwide. Due to its association with the development of gastric adenocarcinoma, updates on its prevalence are of interest to the internist or gastroenterologist and policymaking. This study measured the prevalence of H. pylori and evaluated its association with endoscopic and histopathological findings in adults with an indication for upper GI endoscopy (EGD). Materials and methods: This analytical cohort study describes the prevalence of H. pylori and assesses risk factors associated with this infection in adult patients undergoing outpatient EGD for any medical indication in the endoscopy unit of a quaternary care university hospital between June and December 2020. Endoscopic and histopathological findings and the prevalence of H. pylori are described. To explore the risk factors, the chi-square (χ2) test was used to evaluate differences in proportions and the Student's t and Mann-Whitney U tests for continuous variables according to their distribution. Results: 613 patients met the selection criteria and were included in the analysis. The most frequent indication for EGD was dyspepsia. The prevalence of H. pylori was 38.5% (95% confidence interval [CI]: 34.7-42.4%). Conclusion: H. pylori is a topic of great interest in gastrointestinal pathologies. The endoscopic search should take place in the antrum and body. Its presence was most common in patients with a normal esophagus, follicular nodular gastritis, duodenal ulcer, and acute inflammation upon the histological study. More studies are required to complement the local epidemiological behavior.

Sedación administrada por médicos generales para procedimientos endoscópicos de baja complejidad: experiencia en una unidad de endoscopia de una clínica de alta complejidad en Cali / Sedation Administered by General Practitioners for Low Complexity Endoscopic Procedures: Experience in an Endoscopy Unit of a Tertiary Referral Hospital in Cali

Resumen Objetivos: en Colombia se ha venido implementando la sedación por médicos no anestesiólogos para procedimientos endoscópicos fuera del quirófano. Se describió la experiencia en la unidad de gastroenterología de una clínica de alto nivel de atención en Cali, Colombia. Materiales y métodos: estudio observacional, de tipo cohorte analítica para describir la frecuencia y el tipo de eventos adversos asociados a los procedimientos de sedación por médicos generales, y evaluar los factores asociados a su ocurrencia en pacientes que acudieron a la unidad de endoscopia de la Fundación Valle del Lili para la realización de estudios endoscópicos bajo sedación intravenosa que, por ser de bajo riesgo, fue aplicada por un médico no anestesiólogo entre noviembre de 2018 y junio de 2019. Se realizó análisis descriptivo, se calcularon mediana y rango intercuartílico para las variables numéricas, y frecuencias para las variables cualitativas. Resultados: se incluyeron 1506 participantes, 59,4 % ASA I y 40,6 % ASA II. En promedio, la dosis inicial de propofol fue de 60 mg y la dosis total, de 140 mg. Se registraron eventos adversos no serios en 46 pacientes (3,05 %) y el más común fue la desaturación transitoria (80,4 %). Ningún paciente presentó eventos adversos serios. El puntaje inicial promedio de la escala de Aldrete fue 8, mientras que al alta el puntaje promedio fue de 10. Conclusiones: la sedación para procedimientos endoscópicos dada por médicos no anestesiólogos es segura, siempre y cuando sea realizado por personal entrenado que realice una adecuada valoración de los antecedentes (cardiovasculares, gastrointestinales y neurológicos) y factores de riesgo del paciente dentro del marco de los lineamientos institucionales vigentes.

Abstract Objectives: in Colombia, sedation by non-anesthesiologists for endoscopic procedures outside the operating room has been implemented. A description of an experience in the gastroenterology unit of a tertiary referral hospital in Cali, Colombia, was conducted. Materials and methods: an analytical cohort observational study to describe the frequency and type of adverse events associated with sedation procedures performed by general practitioners and evaluate the factors related to their occurrence in patients who attended the endoscopy unit of Fundación Valle del Lili for endoscopic studies under intravenous sedation. Between November 2018 and June 2019, non-anesthesiologist physicians performed this procedure due to the minimal risk implied. A descriptive analysis was completed, and the median and interquartile range were calculated for numerical variables and frequencies for qualitative variables. Results: There were 1506 participants, 59.4% ASA I and 40.6% ASA II in this study. On average, the starting dose of propofol was 60 mg, and the total dose was 140 mg. Forty-six patients (3.05%) reported non-severe adverse events; the most common occurrence was transient desaturation (80.4%). No patients experienced severe adverse events. The average initial Aldrete scale score was 8, while at discharge, the average score was 10. Conclusions: sedation for endoscopic procedures performed by non-anesthesiologists is safe provided that it is performed by trained personnel conducting a correct assessment of the patient's (cardiovascular, gastrointestinal, and neurological) history and risk factors within the framework of the current institutional guidelines.

Características clínicas de pacientes con pancreatitis aguda atendidos en un hospital de alta complejidad en Cali / Clinical characteristics of patients with acute pancreatitis treated in a tertiary referral hospital in Cali

Resumen Introducción: la pancreatitis aguda (PA) es una enfermedad de alta complejidad clínica y, de acuerdo con su gravedad, puede tener una elevada morbimortalidad con altos costos para el sistema de salud, especialmente a nivel intrahospitalario. Materiales y métodos: se desarrolló un estudio descriptivo basado en historias clínicas de un hospital universitario de alta complejidad. Se revisaron las historias con diagnóstico CIE 10 de pancreatitis aguda entre enero de 2011 y diciembre de 2018. Se incluyeron todos los pacientes mayores de 18 años, de ambos sexos, con diagnóstico de PA por cumplimiento de al menos 2 de los criterios de Atlanta de 2012. Resultados: se revisaron 1353 historias clínicas, de las cuales 386 cumplieron criterios para PA. Entre ellas se identificaron 205 mujeres (53 %) y 181 hombres (47 %), y la prevalencia de comorbilidades fue inferior al 10 %. El 38 % de los casos de pancreatitis ocurrieron en personas entre los 50 y 70 años de edad. Con respecto a la etiología de la PA, el origen biliar fue el de mayor frecuencia, con 200 casos del total (52 %); seguido de idiopático (19,7 %) y poscolangiopancreatografía retrógrada endoscópica (CPRE), que ocurrió en 33 pacientes (8,5 %). Conclusiones: la PA es una entidad frecuente que afecta a adultos de todas las edades y genera una cantidad importante de consultas en urgencias. En Colombia, los datos previos apuntaban a pacientes con pancreatitis graves y no se tenía conocimiento del comportamiento sociodemográfico y clínico de las pancreatitis agudas en urgencias.

Abstract Introduction: Acute pancreatitis (AP) is a disease with a high degree of clinical complexity, and depending on its severity, it can have high morbidity and mortality rates, resulting in substantial health-care costs, particularly at the hospital level. Materials and methods: A descriptive study was developed based on the medical records of a tertiary referral university hospital. The records that included an ICD 10 diagnosis of acute pancreatitis between January 2011 and December 2018 were reviewed. All patients over the age of 18, of both sexes, with an AP diagnosis who met at least two of the 2012 Atlanta criteria were included in the study. Results: 1 353 records were reviewed, of which 386 met the criteria for AP. There were 205 women (53%) and 181 males (47%) among them, and comorbidities were found in less than 10% of the participants. 38% of cases of pancreatitis occurred in people between 50 and 70 years of age. Regarding the etiology of AP, biliary origin was the most frequent with 200 cases (52%), followed by idiopathic (19.7%) and post-endoscopic retrograde cholangiopancreatography (ERCP) in 33 patients (8.5%). Conclusions: AP is a common condition that affects adults of all ages and results in a high number of emergency room visits. Previous data in Colombia was only available for individuals with severe pancreatitis, and nothing was known about the sociodemographic and clinical characteristics of acute pancreatitis in the emergency room.

Situación de salud bucal de párvulos chilenos en un contexto comunitario / Oral health situation of Chilean children in a community context

INTRODUCCIÓN: Determinar la situación de salud bucal en párvulos ingresados a un programa promocional-preventivo en la comuna de Melipilla durante el año 2018. MATERIAL Y MÉTODOS: Estudio transversal realizado en 860 párvulos de entre dos a cinco años de edad matriculados en 17 establecimientos educacionales de la comuna, ubicados en zona urbana y rural. La experiencia de caries dental como variable dependiente y sexo, edad y zona geográfica del establecimiento educacional (urbano-rural) como variable independiente fueron medidas en un contexto comunitario (en aula). Estudio aprobado por Comité Científico de Ética de Universidad Finis Terrae y Servicio de Salud Metropolitano Occidente. RESULTADOS: El estudio abarcó al 88,5% de los párvulos matriculados, con promedio de edad de 3,76 ± 1,06 años. El 53,5% correspondieron a niñas. Un 34,1% (IC:95% 30,74:37,48) presentó caries dental, sin diferencias por sexo, zona geográfica, si por edad. A mayor edad, mayor daño por caries dental. Cada párvulo en promedio presentó un diente primario con caries (diente cariado:1,14 ± 2,28). El tercio de la población más afectada por caries dental presentó en promedio tres dientes primarios con daño. DISCUSIÓN: Los resultados muestran un elevado daño por caries dental cuyo inicio es temprano; esto pone de manifiesto la necesidad de avanzar en el desarrollo de políticas públicas de salud bucal destinadas a la primera infancia. (AU)

INTRODUCTION: To determine the oral health situation in the infants admitted to a pro-motional-preventive program in the municipality of Melipilla during the year 2018.MATERIAL AND METHODS: Cross-sectional study conducted with 860 infants between two to five years of age enrolled in 17 educational establishments in the community, located in urban and rural settings. The incidence of cavities as related to the variables of sex, age and geographical area of the educational establishment (urban-rural) as an independent variables were measured in a community context (in the classroom). Study approved by the Scientific Committee of Ethics of the Finis Terrae University and the Western Metropolitan Health Service.RESULTS: The study covered 88.5% of the enrolled children of 3.76 ± 1.06 years with an average age of 3,76 ± 1,06. 53.5% were girls. 34.1% (IC:95% 30,74:37,48) had cavities, without differences by sex or geographical area, but by age. The older you get, the more damage you get from tooth decay. Each toddler had on average one primary tooth with cavities (decayed tooth: 1.14 ± 2.28). One third of the population most affected by cavities presented on average three primary teeth with damage.DISCUSSION: The results show a high damage by cavities whose onset is early; This highlights the need to improve the development of public oral health policies aimed at early childhood. (AU)

Schwann Cell Autophagy and Necrosis as Mechanisms of Cell Death by Acanthamoeba.

Amoebae of the genus Acanthamoeba are etiological agents of granulomatous amoebic encephalitis (GAE). Recently, through an in vivo GAE model, Acanthamoeba trophozoites were immunolocalized in contact with the peripheral nervous system (PNS) cells-Schwann cells (SC). In this study, we analyzed in greater detail the in vitro early morphological events (1, 2, 3, and 4 h) during the interaction of A. culbertsoni trophozoites (ATCC 30171) with SC from Rattus norvegicus (ATCC CRL-2941). Samples were processed for scanning and transmission electron microscopy as well as confocal microscopy. After 1 h of interaction, amoebae were observed to be adhered to the SC cultures, emitting sucker-like structures associated with micro-phagocytic channels. In addition, evidence of necrosis was identified since edematous organelles as well as multivesicular and multilamellar bodies characteristics of autophagy were detected. At 2 h, trophozoites migrated beneath the SC culture in which necrosis and autophagy persisted. By 3 and 4 h, extensive lytic zones were observed. SC necrosis was confirmed by confocal microscopy. We reported for the first time the induction of autophagic and necrotic processes in PNS cells, associated in part with the contact-dependent pathogenic mechanisms of A. culbertsoni trophozoites.

Descripción clínico-epidemiológica de pacientes con enfermedad inflamatoria intestinal en una clínica de cuarto nivel en Cali / Clinical-epidemiological description of patients with inflammatory bowel disease in a fourth level clinic in Cali

Resumen Introducción: en América Latina, la enfermedad inflamatoria intestinal (EII) es poco frecuente y la información, limitada. Se describieron características de los pacientes con EII en una unidad de gastroenterología de una clínica de alto nivel de atención en Cali, Colombia. Materiales y métodos: estudio descriptivo de pacientes que consultaron con diagnóstico de enfermedad de Crohn (EC) o colitis ulcerativa (CU) a la Clínica Fundación Valle del Lili entre enero de 2011 y diciembre de 2015. Se realizó un análisis con Statistical Package for the Social Sciences de IBM (SPSS) versión 19, se calcularon la mediana y el rango intercuartílico para las variables numéricas, y frecuencias para las variables cualitativas. Resultados: se incluyeron 416 participantes, 115 con EC y 301 con CU. El 41 % se clasificó como enfermedad leve, 23,5 % moderada y 35,3 % grave. Se realizó cirugía a 24 pacientes (9,0 %) con CU y 53 (46,1 %) con EC. En esta última, el manejo más frecuente fue los medicamentos biológicos (32,2 %), seguidos de inmunomoduladores (27,8 %), esteroides (20 %) y ácido 5-aminosalicílico (5-ASA) (11,3 %). El tratamiento más frecuente de CU fue 5-ASA (84,8 %), seguido de esteroides (32,19 %), azatioprina (24,6 %) y biológicos (15,9 %). Conclusiones: el diagnóstico precoz sigue siendo un reto. La gravedad de la CU en los pacientes estudiados fue menor a la reportada en el mundo, lo cual no ocurrió con los pacientes con EC y podría estar en relación con el retraso diagnóstico. El uso de medicamentos biológicos se acercó a lo reportado en el primer mundo. Es difícil determinar si las menores tasas de cirugía se deben a una mejor respuesta clínica o a un difícil acceso a estas intervenciones.

Abstract Objectives: In Latin America, inflammatory bowel disease (IBD) is rare, and information about it is limited. This article describes characteristics of IBD patients in a gastroenterology unit at a high-level clinic in Cali, Colombia. Materials and methods: This is a descriptive study of patients diagnosed with Crohn's disease (CD) or ulcerative colitis (UC) at the Clínica Fundación Valle de Lili between January 2011 and December 2015. Statistical analysis was performed with SPSS version 19. Medians and interquartile ranges were calculated for numerical variables. Frequencies were calculated for qualitative variables. Results: The 416 participants included 115 with CD and 301 with UC. Of the total cases, 41% were classified as mild, 23.5% as moderate and 35.3% as severe. Surgery was performed in 24 patients (9.0%) with UC and 53 (46.1%) with CD. CD was most frequently managed with biologicals (32.2%), followed by immunomodulators (27.8%), steroids (20%) and 5-ASA (11.3%). The most frequent treatment for UC was 5-ASA (84.8%), but 32.19% received steroids, 24.6% received azathioprine and 15.9% received biologicals. Conclusions: Early diagnosis remains a challenge. The severity of UC but not CD in the patients studied was less than that reported elsewhere in the world. The difference could be related to diagnostic delay. The use of biologicals was close to that reported in the first world. It is difficult to determine if lower surgery rates are due to better clinical response or to difficult access to these interventions.

A Low Cost Antibody Signal Enhancer Improves Immunolabeling in Cell Culture, Primate Brain and Human Cancer Biopsy.

The use of antibodies to identify neuronal receptors, neurotransmitters, cytoskeletal elements or pathologic protein aggregates, ion channels, adhesion molecules or other cell-type specific markers, is common practice in neuroscience. Antibody detection systems are often based on confocal, epifluorescence or brightfield microscopy. Three types of technical issues can interfere with immunolabeling: low abundance of the target protein, low specific affinity of the antibody and/or signal background sometimes related to tissue fixation. Here, giving tribute to Professor Miledi's mentorship, we propose the application of an antibody signal enhancer (ASE) solution based on glycine, hydrogen peroxide and a detergent mix as a simple, low cost, protocol variation that significantly and specifically improves the signal to noise ratio during immunostaining experiments. We describe three new settings in which ASE improves the detection of a variety of antibodies applied on long-time stored non-human primate brain sections, cell culture monolayers and on squamous carcinomas retrieved from cervical cancer patients. The significant improvement of ASE over optimized immunohistochemical protocols used in clinical practice (i.e. cancer detection) combined with its simplicity and low cost makes it an attractive method for biomedical applications.

Heterotopia de mucosa gástrica en el intestino delgado, hallazgo en videocápsula endoscópica. Reporte de caso / An endoscopic videocapsule finding of heterotopia of the gastric mucosa of the small intestine

Resumen Introducción: la heterotopia de mucosa gástrica se refiere a la localización ectópica de mucosa gástrica en cualquier parte del tracto gastrointestinal. Es una causa poco frecuente de úlceras gastrointestinales y sangrado digestivo oculto. La videocápsula endoscópica se ha convertido en una herramienta fundamental para el estudio del intestino delgado. Métodos: estudio descriptivo de reporte de caso. La información de la historia clínica, reporte de patología y estudios endoscópicos, se extrajo de las bases de datos de la Fundación Valle del Lili. Resultados: paciente masculino de 71 años, en quien se realizó videocápsula endoscópica por un sangrado digestivo oculto y se encontraron segmentos de estenosis y úlceras en el yeyuno. La histopatología reveló la presencia de mucosa gástrica heterotópica. Conclusión: la heterotopia de mucosa gástrica debe considerarse como una causa posible de sangrado del intestino delgado.

Abstract Introduction: Heterotopia of the gastric mucosa refers to an ectopic location of gastric mucosa in any part of the gastrointestinal tract. It is a rare cause of gastrointestinal ulcers and occult digestive bleeding. Endoscopic videocapsules have become fundamental tools for study of the small intestine. Methods: This is a descriptive case study based on information from the medical history, pathology report and endoscopic studies extracted from the databases of the Fundación Valle del Lili in Cali, Colombia. Results: An endoscopic videocapsule was used to examine a 71-year-old male patient who suffered from occult digestive bleeding. Segments of stenosis and ulcers were found in the jejunum and histopathology revealed heterotopic gastric mucosa. Conclusion: Heterotopy of the gastric mucosa should be thought of as a possible cause of bleeding in the small intestine.

Ouabain Modulates the Adherens Junction in Renal Epithelial Cells.

BACKGROUND/AIMS: Ouabain, a well-known plant-derived toxin, is also a hormone found in mammals at nanomolar levels that binds to a site located in the a-subunit of Na⁺,K⁺-ATPase. Our main goal was to understand the physiological roles of ouabain. Previously, we found that ouabain increases the degree of tight junction sealing, GAP junction-mediated communication and ciliogenesis. Considering our previous results, we investigated the effect of ouabain on adherens junctions. METHODS: We used immunofluorescence and immunoblot methods to measure the effect of 10 nM ouabain on the cellular and nuclear content of E-cadherin, ß-catenin and γ-catenin in cultured monolayers of Marin Darby canine renal cells (MDCK). We also studied the effect of ouabain on adherens junction biogenesis through sequential Ca²âº removal and replenishment. Then, we investigated whether c-Src and ERK1/2 kinases are involved in these responses. RESULTS: Ouabain enhanced the cellular content of the adherens junction proteins E-cadherin, ß-catenin and γ-catenin and displaced ß-catenin and γ-catenin from the plasma membrane into the nucleus. Ouabain also increased the expression levels of E-cadherin and ß-catenin in the plasma membrane after Ca²âº replenishment. These effects on adherens junctions were sensitive to PP2 and PD98059, suggesting that they depend on c-Src and ERK1/2 signaling. The translocation of ß-catenin and γ-catenin into the nucleus was specific because ouabain did not change the localization of the tight junction proteins ZO-1 and ZO-2. Moreover, in ouabain-resistant MDCK cells, which express a Na⁺,K⁺-ATPase α1-subunit with low affinity for ouabain, this hormone was unable to regulate adherens junctions, indicating that the ouabain receptor that regulates adherens junctions is Na⁺,K⁺-ATPase. CONCLUSION: Ouabain (10 nM) upregulated adherens junctions. This novel result supports the proposition that one of the physiological roles of this hormone is the modulation of cell contacts.

Differential homologous desensitization of the human histamine H3 receptors of 445 and 365 amino acids expressed in CHO-K1 cells.

Histamine H3 receptors (H3Rs) signal through Gαi/o proteins and are found in neuronal cells as auto- and hetero-receptors. Alternative splicing of the human H3R (hH3R) originates 20 isoforms, and the mRNAs of two receptors of 445 and 365 amino acids (hH3R445 and hH3R365) are widely expressed in the human brain. We previously showed that the hH3R445 stably expressed in CHO-K1 cells experiences homologous desensitization. The hH3R365 lacks 80 residues in the third intracellular loop, and in this work we therefore studied whether this isoform also experiences homologous desensitization and the possible differences with the hH3R445. In clones of CHO-K1 cells stably expressing similar receptor levels (211 ± 12 and 199 ± 16 fmol/mg protein for hH3R445 and hH3R365, respectively), there were no differences in receptor affinity for selective H3R ligands or for agonist-induced [35S]-GTPγS binding to membranes and inhibition of forskolin-stimulated cAMP accumulation in intact cells. For both cell clones, pre-incubation with the H3R agonist RAMH (1 µM) resulted in functional receptor desensitization, as indicated by cAMP accumulation assays, and loss of receptors from the cell surface and reduced affinity for the agonist immepip in cell membranes, evaluated by radioligand binding. However, functional desensitization differed in the maximal extent (96 ± 15% and 58 ± 8% for hH3R445 and hH3R365, respectively) and the length of pre-exposure required to reach the maximum desensitization (60 and 30 min, respectively). Furthermore, the isoforms differed in their recovery from desensitization. These results indicate that the hH3R365 experiences homologous desensitization, but that the process differs between the isoforms in time-course, magnitude and re-sensitization.

Acanthamoeba (T4) trophozoites cross the MDCK epithelium without cell damage but increase paracellular permeability and transepithelial resistance by modifying tight junction composition.

Free-living amoebae of the genus Acanthamoeba are protozoa ubiquitously found in nature. Some species of the genus are potentially pathogenic for humans provoking keratitis in healthy individuals, often in contact lens wearers and opportunistic infections such as pneumonitis, fatal granulomatous encephalitis and skin infections, particularly in immunocompromised individuals. The pathogenic mechanisms of these amoebae are poorly understood, however it had been suggested that contact dependent mechanisms are important during invasion, regardless of the epithelia type, since amoebae penetrate epithelia separating tight junction (TJ). This study was undertaken to determine whether Acanthamoeba sp. (T4) damages the barrier function of the TJ in MDCK epithelial monolayers. Actin cytoskeleton staining and electron microscopy analyses were performed; paracellular permeability and TJ sealing were evaluated by apicobasolateral diffusion of ruthenium red and transepithelial resistance (TER) measurements; immunofluorescence and Western blot assays were performed to locate and estimate expression of TJ protein claudins 2 (Cldn2) and 4 (Cldn4). The results show that Acanthamoeba sp. crosses the MDCK monolayer without altering the actin cytoskeleton or the morphology of the cells. When trophozoites or conditioned medium interact with the monolayer, paracellular diffusion of ruthenium red increases. After 6 h, the amoebae, but not their conditioned medium, increase the TER, and Cldn2 is removed from the TJ, and its overall content in the cells diminishes, while Cldn4 is targeted to the TJ without changing its expression level. In conclusion Acanthamoeba (T4) crosses MDCK monolayer without damaging the cells, increasing permeability and TER through Cldn2 degradation, and redirecting Cldn4 to TJ. These results strongly suggest that contact-dependent mechanisms are relevant during amoebae invasion.

Acanthamoeba culbertsoni isolated from a clinical case with intraocular dissemination: Structure and in vitro analysis of the interaction with hamster cornea and MDCK epithelial cell monolayers.

Acanthamoeba culbertsoni trophozoites, previously isolated from a human keratitis case with severe intraocular damage, were maintained in axenic culture. Co-incubation of amoebae with MDCK cell monolayers demonstrated an apparent preference of the amoebae to introduce themselves between the cells. The trophozoites appeared to cross the cell monolayer through the tight junctions, which resulted in decreased trans-epithelial resistance (TER) measurements. Unexpectedly, after co-incubation of amoebae with hamster corneas, we observed that the trophozoites were able to cross the different cell layers and reach the corneal stroma after only 12 h of interaction, in contrast to other Acanthamoeba species. These observations suggest that this A. culbertsoni isolate is particularly pathogenic. Further research with diverse methodologies needs to be performed to explain the unique behavior of this Acanthamoeba strain.

Ouabain Modulates the Distribution of Connexin 43 in Epithelial Cells.

BACKGROUND/AIMS: The fact that ouabain has been identified as an endogenous substance, led us to inquire its physiological role in epithelial cells. Based on previous observations, we hypothesized that it influences processes related to cell contacts. Previously we have shown that nanomolar concentrations of ouabain up-regulate tight junctions, accelerate ciliogenesis, and increase gap junctional intercellular communication (GJIC). Given that silencing assays indicated that connexin 43 (Cnx43) is involved in the GJIC response, in the present work we study whether ouabain affects Cnx43 expression and distribution. METHODS: We seeded confluent monolayers of epithelial renal MDCK cells and incubated them with 10 nM ouabain during 1 h. Then we measured, by densitometric analysis of Western blot assays, the amount of Cnx43 in cells and in fractions enriched of plasma membrane. We also studied its localization with immunofluorescence and confocal microscopy. RESULTS: Cnx43 is remarkably displayed, outlining the borders of cells gathered in clusters, randomly scattered throughout the monolayer. Ouabain increases the density of such clusters, as well as the average number of cells per cluster, without inducing the synthesis of new Cnx43. It also promotes relocation towards the membrane, of subunits already available. The fact that such changes are inhibited by PP2 and PD98059 indicates that a signaling pathway, that includes c-Src and ERK1/2, is involved in this response. CONCLUSION: Ouabain induces the translocation of Cnx43 from the cytoplasm to the plasma membrane. These findings support our hypothesis that one of the physiological roles of ouabain is the modulation of physiological processes that depend on cell to cell contacts.

Guía de práctica clínica para la enfermedad por reflujo gastroesofágico / Clinical practice guideline for disease caused by gastroesophageal reflux

Objetivo: brindar una guía de práctica clínica basada en la evidencia más reciente para el diagnóstico y tratamiento del reflujo gastroesofágico teniendo en cuenta la efectividad y seguridad de las intervenciones dirigidas a pacientes, personal asistencial, administrativo y entes gubernamentales de cualquier servicio de atención en Colombia. Materiales y métodos: esta guía fue desarrollada por un equipo multidisciplinario con apoyo de la Asociación Colombiana de Gastroenterología, el Grupo Cochrane ITS y el Instituto de Investigaciones Clínicas de la Universidad Nacional de Colombia. Se desarrollaron preguntas clínicas relevantes y se realizó la búsqueda de guías nacionales e internacionales en bases de datos especializadas. Las guías existentes fueron evaluadas en términos de calidad y aplicabilidad; 1 guía cumplió los criterios de adaptación, por lo que se decidió adaptar 3 preguntas clínicas. El Grupo Cochrane realizó la búsqueda sistemática de la literatura. Las tablas de evidencia y recomendaciones fueron realizadas con base en la metodología GRADE. Las recomendaciones de la guía fueron socializadas en una reunión de expertos con entes gubernamentales y pacientes. Resultados: se desarrolló una guía de práctica clínica basada en la evidencia para el diagnóstico y tratamiento de pacientes con reflujo gastroesofágico en Colombia. Conclusiones: el diagnóstico y manejo oportuno de los pacientes con ERGE contribuirá a disminuir la carga de la enfermedad en Colombia, así como de las enfermedades asociadas.

Objective: To provide a clinical practice guideline with the latest evidence for diagnosis and treatment of gastroesophageal reflux for patients, caregivers, administrative and government bodies at all levels of care in Colombia. Materials and Methods: This guide was developed by a multidisciplinary team with the support of the Colombian Association of Gastroenterology, Cochrane STI Group and Clinical Research Institute of the Universidad Nacional de Colombia. Relevant clinical questions were developed and the search for national and international guidelines in databases was performed. Existing guidelines were evaluated quality and applicability. One guideline met the criteria for adaptation, so the group decided to adapt 3 clinical questions. Systematic literature searches were conducted by the Cochrane Group. The tables of evidence and recommendations were made based on the GRADE methodology. The recommendations of the guide were socialized in a meeting of experts with government agencies and patients. Results: An evidence-based Clinical Practice Guidelines for the diagnosis and treatment of gastroesophageal reflux was developed for the Colombian context. Conclusions: The opportune detection and appropriate management of gastroesophageal reflux would contribute to the burden of the disease in Colombia and its associated diseases.

EGF regulates claudin-2 and -4 expression through Src and STAT3 in MDCK cells.

Epidermal Growth Factor (EGF) is a key regulator of epithelial paracellular permeability, a property that depends on tight junctions (TJ) and can be evaluated through the measurement of the transepithelial electrical resistance (TER). EGF increases the TER of MDCK monolayers by inducing ERK1/2-dependent downregulation of claudin-2 (CLDN-2) and upregulation of claudin-4 (CLDN-4). Because either increments or decrements in TER often involve Src activation and epithelial cell differentiation occasionally depends on STAT3, here we investigated whether EGF might control CLDN-2 downregulation and CLDN-4 upregulation through those proteins. We found that EGF induces Src activation necessary for the reduction of CLDN-2 at the TJ, the degradation of this CLDN, the reduction of the cellular levels of its mRNA and the resulting increase of TER. EGF-induced changes on CLDN-2 protein and mRNA also depend on STAT3 activity. This growth factor increases the levels of STAT3 phosphorylated at Y705 in the nucleus, a process that depends on Src activation. Interestingly, Src and STAT3 activation do not exclusively mediate the EGF-induced downregulation of CLDN-2, but they are also implicated in the EGF-induced CLDN-4 transcription, translation, and exocytic fusion into TJ. Our results indicate that EGF controls the levels of CLDN-2 and -4 proteins and mRNAs through Src and STAT3 activity.

Ouabain induces endocytosis and degradation of tight junction proteins through ERK1/2-dependent pathways.

In addition to being a very well-known ion pump, Na(+), K(+)-ATPase is a cell-cell adhesion molecule and the receptor of digitalis, which transduces regulatory signals for cell adhesion, growth, apoptosis, motility and differentiation. Prolonged ouabain (OUA) blockage of activity of Na(+), K(+)-ATPase leads to cell detachment from one another and from substrates. Here, we investigated the cellular mechanisms involved in tight junction (TJ) disassembly upon exposure to toxic levels of OUA (≥300 nM) in epithelial renal canine cells (MDCK). OUA induces a progressive decrease in the transepithelial electrical resistance (TER); inhibitors of the epidermal growth factor receptor (EGFR, PD153035), cSrc (SU6656 and PP2) and ERK1/2 kinases (PD98059) delay this decrease. We have determined that the TER decrease depends upon internalization and degradation of the TJs proteins claudin (CLDN) 2, CLDN-4, occludin (OCLN) and zonula occludens-1 (ZO-1). OUA-induced degradation of proteins is either sensitive (CLDN-4, OCLN and ZO-1) or insensitive (CLDN-2) to ERK1/2 inhibition. In agreement with the protein degradation findings, OUA decreases the cellular content of ZO-1 and CLDN-2 mRNAs but surprisingly, increases the mRNA of CLDN-4 and OCLN. Changes in the mRNA levels are sensitive (CLDN-4, OCLN and ZO-1) or insensitive (CLDN-2) to ERK1/2 inhibition as well. Thus, toxic levels of OUA activate the EGFR-cSrc-ERK1/2 pathway to induce endocytosis, internalization and degradation of TJ proteins. We also observed decreases in the levels of CLDN-2 protein and mRNA, which were independent of the EGFR-cSrc-ERK1/2 pathway.