Bacterial-associated cholera toxin and GM 1 binding are required for transcytosis of classical biotype Vibrio cholerae through an in vitro M cell model system

To elucidate mechanisms involved in M cell uptake and transcytosis of Vibrio cholerae , we used an in vitro model of human M-like cells in a Caco-2 monolayer. Interspersed among the epithelial monolayer of Caco-2 cells we detect cells that display M-like features with or without prior lymphocyte treatment and we have established key parameters for V. cholerae transcytosis in this model. Cholera toxin (CT) mutants lacking the A subunit alone or both the A and B subunits were deficient for transcytosis. We explored this finding further and showed that expression of both subunits is required for binding by whole V. cholerae to immobilized CT receptor, the glycosphingolipid GM 1 . Confocal microscopy showed CT associated with transcytosing bacteria, and transcytosis was inhibited by pre-incubation with GM 1 before infection. Finally, heat treatment of the bacterial cells caused a loss of binding to GM 1 that was correlated with a significant decrease in uptake and transcytosis by the monolayer. Our data support a model in which the ability of bacteria to interact with GM 1 in a CT-dependent fashion plays a critical role in transcytosis of V. cholerae by M cells.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74960/1/j.1462-5822.2005.00681.x.pd

Prior Helicobacter pylori infection ameliorates Salmonella typhimurium-induced colitis: Mucosal crosstalk between stomach and distal intestine

Background: Helicobacter pylori infection is associated with a lower risk of chronic autoimmune diseases including inflammatory bowel disease (IBD). H. pylori modulates the gastric immune response, decreasing the local inflammatory response to itself. In mice, chronic Salmonella typhimurium infection induces colitis similar to Crohn's disease, characterized by inflammation, which progresses toward fibrosis. The aim of this study was to determine whether prior H. pylori infection acts at a distance to modulate the immune response of S. typhimurium -induced colitis. Methods: Mice were infected with the mouse-adapted strain of H. pylori (SS1), followed by infection with S. typhimurium . The effect of H. pylori on colitis was determined by gross pathology, histopathology, cytokine response, and development of fibrosis in the cecum. Gastritis and systemic immune response was measured in response to infection. Results: H. pylori suppresses the Th17 response to S. typhimurium infection in the mouse cecum, but does not alter the Th2 or T-regulatory response or the development of fibrosis. H. pylori infection induces IL-10 in the mesenteric lymph nodes, suggesting an extragastric mechanism for immunomodulation. H. pylori / S. typhimurium coinfection decreases inflammation in both the cecum and the stomach. Conclusions: This study demonstrates a potential mechanism for the negative association between H. pylori and IBD in humans. H. pylori represses the lower gastrointestinal tract Th17 response to bacterially induced colitis via extragastric immunomodulatory effects, illustrating immunological crosstalk between the upper and lower gastrointestinal tract. (Inflamm Bowel Dis 2011;)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/84386/1/21489_ftp.pd

Outdoor Field Experience with Autonomous RPC Based Stations

In the last two decades Resistive Plate Chambers were employed in the Cosmic Ray Experiments COVER-PLASTEX and ARGO/YBJ. In both experiments the detectors were housed indoors, likely owing to gas distribution requirements and the need to control environment variables that directly affect RPCs operational stability. But in experiments where Extended Air Shower (EAS) sampling is necessary, large area arrays composed by dispersed stations are deployed, rendering this kind of approach impossible. In this situation, it would be mandatory to have detectors that could be deployed in small standalone stations, with very rare opportunities for maintenance, and with good resilience to environmental conditions. Aiming to meet these requirements, we started some years ago the development of RPCs for Autonomous Stations. The results from indoor tests and measurements were very promising, both concerning performance and stability under very low gas flow rate, which is the main requirement for Autonomous Stations. In this work we update the indoor results and show the first ones concerning outdoor stable operation. In particular, a dynamic adjustment of the high voltage is applied to keep gas gain constant.Peer Reviewe

MARTA: A high-energy cosmic-ray detector concept with high-accuracy muon measurement

A new concept for the direct measurement of muons in air showers is presented. The concept is based on resistive plate chambers (RPCs), which can directly measure muons with very good space and time resolution. The muon detector is shielded by placing it under another detector able to absorb and measure the electromagnetic component of the showers such as a water-Cherenkov detector, commonly used in air shower arrays. The combination of the two detectors in a single, compact detector unit provides a unique measurement that opens rich possibilities in the study of air showers.Comment: 11 page

Targeting mitochondrial oxidative stress with MitoQ reduces NET formation and kidney disease in lupus-prone MRL-lpr mice.

OBJECTIVES: Recent investigations in humans and mouse models with lupus have revealed evidence of mitochondrial dysfunction and production of mitochondrial reactive oxygen species (mROS) in T cells and neutrophils. This can provoke numerous cellular changes including oxidation of nucleic acids, proteins, lipids and even induction of cell death. We have previously observed that in T cells from patients with lupus, the increased mROS is capable of provoking oligomerisation of mitochondrial antiviral stimulator (MAVS) and production of type I interferon (IFN-I). mROS in SLE neutrophils also promotes the formation of neutrophil extracellular traps (NETs), which are increased in lupus and implicated in renal damage. As a result, in addition to traditional immunosuppression, more comprehensive treatments for lupus may also include non-immune therapy, such as antioxidants. METHODS: Lupus-prone MRL-lpr mice were treated from weaning for 11 weeks with the mitochondria-targeted antioxidant, MitoQ (200 µM) in drinking water. Mice were then assessed for ROS production in neutrophils, NET formation, MAVS oligomerisation, serum IFN-I, autoantibody production and renal function. RESULTS: MitoQ-treated mice manifested reduced neutrophil ROS and NET formation, decreased MAVS oligomerisation and serum IFN-I, and reduced immune complex formation in kidneys, despite no change in serum autoantibody . CONCLUSIONS: These findings reveal the potential utility of targeting mROS in addition to traditional immunosuppressive therapy for lupus

Validation of an IGF1 Screening Method for Retinopathy of Pre-maturity

Retinopathy of pre-maturity (ROP) is a retinal disease that causes arrest of vascularization of the retina and can result in retinal detachment and blindness. Current screening protocols may not be sufficiently accurate to identify all at-risk patients. The aim of this study is to validate a method for improved identification of newborns at risk of ROP. We conducted a prospective clinical trial of pre-term newborns <32 weeks of gestation and/or <1,500 g birth weight during a 6-year period in a tertiary care hospital. We applied our new method based on measurement of insulin-like growth factor 1 (IGF1) levels at 3 weeks of age and the presence of sepsis during the first 3 weeks of life. Our screening protocol allowed exclusion of 121 (79.1%) patients for whom American Academy of Pediatrics (AAP) guidelines recommended screening, had a negative predictive value of 100%, and correctly identified all patients with ROP. Following retrospective assessment of our data based on these findings, we propose further restriction of the current AAP indications for screening to <1,100 g and <28 weeks of gestation in order to improve diagnostic efficacy while ensuring optimal use of restriction of human and material resources

Transplante autólogo “melhorado” stem cells medula óssea cd34+ em pacientes com angina refratária: estudo piloto

Objective: To evaluate the efficacy of 6 months of autologous CD34+ stem cells in bone marrow “enhanced” by ischemic preconditioning in patients with refractory angina.Methods: A pilot study with 14 patients with refractory angina, with a functional class greater than or equal to III clinical (NYHA and CCS), of the Department of Cardiology of the Central Military Hospital. They were selected by convenience 14 patients who were randomly assigned to two groups, the first (intervention) with autologous stem cells CD34+ bone marrow powered by ischemic preconditioning, intravenously more conventional medical treat­ment, and the second (control) with conventional medical treatment. Baseline measurements were performed and six months’ threshold angina/ischemia measured in mets and functional class.Results: Comparing the medians, the change in threshold value angina/ischemia six months later for the interven­tion group was 3.5 mets vs 0.9 mets for the control group P = 0.013. No inherent complications to treatment were recorded.Conclusions: In this study patients with refractory angina who underwent autologous stem cell transplant of bone marrow CD34+ powered by ischemic preconditioning, showed an improvement in threshold angina and functional class of 6 months.Objetivo: Evaluar la eficacia a 6 meses del trasplante autólogo de células madre CD34+ de médula ósea “potenciado”, mediante pre-condicionamiento isquémico en pacientes con angina refractaria.Métodos: Estudio piloto con 14 pacientes con angina refractaria, clase funcional clínica mayor o igual a III (NYHA y CCS), del Servicio de Cardiología del Hospital Militar Central. Fueron seleccionados por conveniencia 14 pacientes los cuales se asignaron aleatoriamente a 2 grupos, el primero (intervención) con trasplante autólogo de células madre CD34+ de médula ósea potenciado mediante pre-condicionamiento isquémico por vía intravenosa más tratamiento médico convencional, y el segundo (control) con tratamiento médico convencional. Se realizaron mediciones basales a 6 meses del umbral de angina/isquemia medido en mets y clase funcional.Resultados: Al comparar las medianas, el cambio en el valor umbral de angina/isquemia 6 meses después, para el grupo intervenido fue de 3.5 mets vs 0.9 mets, para el grupo control P= 0.013. No se registraron complicaciones inherentes al tratamiento.Conclusiones: En esta investigación, los pacientes con angina refractaria intervenidos con trasplante autólogo de células madre de médula ósea CD34+ potenciado mediante precondicionamiento isquémico mostraron mejoría del umbral de angina y clase funcional a 6 meses. Objetivo: Avaliar a eficácia de 6 meses de células-tronco autólogas CD34 + na medula óssea “aumentada” pelo pré-condicionamento isquêmico em pacientes com angina refratária.Métodos: Um estudo piloto com 14 pacientes com angina refratária, com classe funcional maior ou igual a III clínica (NYHA e CCS), Do Departamento de Cardiologia do Hospital Militar Central. Eles foram selecionados por conveniência 14 pacientes que foram aleatoriamente designados para dois grupos, a primeira (intervenção) com cé­lulas-tronco autólogas CD34+ medula óssea alimentado por pré-condicionamento isquêmico, tratamento intravenoso mais convencional, e o segundo (controle) com tratamento médico convencional. Medidas de linha de base foram realizadas e seis meses de angina limiar /isquemia medido em mets e classe funcional.Resultados: Comparando as mediana, a alteração do valor limiar angina / isquemia seis meses depois para o grupo de intervenção foi de 3,5 mets vs 0,9 mets para o grupo de controlo P = 0,013. Não foram registadas complicações inerentes ao tratamento.Conclusões: Neste estudo, pacientes com angina refratária submetidos a transplante de células-tronco autólogas de medula óssea CD34+ alimentado por pré-condicionamento isquêmico, apresentaram melhora da angina limiar e classe funcional de 6 meses