Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Cell Rep Methods ; 3(2): 100398, 2023 02 27.
Artículo en Inglés | MEDLINE | ID: mdl-36936072

RESUMEN

Unlocking and quantifying fundamental biological processes through tissue microscopy requires accurate, in situ segmentation of all cells imaged. Currently, achieving this is complex and requires exogenous fluorescent labels that occupy significant spectral bandwidth, increasing the duration and complexity of imaging experiments while limiting the number of channels remaining to address the study's objectives. We demonstrate that the excitation light reflected during routine confocal microscopy contains sufficient information to achieve accurate, label-free cell segmentation in 2D and 3D. This is achieved using a simple convolutional neural network trained to predict the probability that reflected light pixels belong to either nucleus, cytoskeleton, or background classifications. We demonstrate the approach across diverse lymphoid tissues and provide video tutorials demonstrating deployment in Python and MATLAB or via standalone software for Windows.


Asunto(s)
Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Procesamiento de Imagen Asistido por Computador/métodos , Imagenología Tridimensional/métodos , Microscopía Confocal/métodos , Redes Neurales de la Computación , Programas Informáticos
2.
ChemMedChem ; 16(22): 3396-3401, 2021 11 19.
Artículo en Inglés | MEDLINE | ID: mdl-34357687

RESUMEN

A selective mono-N-arylation strategy of amidines under Chan-Lam conditions is described. During the reaction optimization phase, the isolation of a mononuclear Cu(II) complex provided unique mechanistic insight into the operation of Chan-Lam mono-N-arylation. The scope of the process is demonstrated, and then applied to access the first mono-N-arylated analogues of pentamidine. Sub-micromolar activity against kinetoplastid parasites was observed for several analogues with no cross-resistance in pentamidine and diminazene-resistant trypanosome strains and against Leishmania mexicana. A fluorescent mono-N-arylated pentamidine analogue revealed rapid cellular uptake, accumulating in parasite nuclei and the kinetoplasts. The DNA binding capability of the mono-N-arylated pentamidine series was confirmed by UV-melt measurements using AT-rich DNA. This work highlights the potential to use Chan-Lam mono-N-arylation to develop therapeutic leads against diamidine-resistant trypanosomiasis and leishmaniasis.


Asunto(s)
Amidinas/farmacología , Antiparasitarios/farmacología , Desarrollo de Medicamentos , Leishmania mexicana/efectos de los fármacos , Pentamidina/farmacología , Amidinas/química , Antiparasitarios/síntesis química , Antiparasitarios/química , Relación Dosis-Respuesta a Droga , Resistencia a Medicamentos/efectos de los fármacos , Estructura Molecular , Pruebas de Sensibilidad Parasitaria , Pentamidina/síntesis química , Pentamidina/química , Relación Estructura-Actividad
3.
Cytometry A ; 97(12): 1222-1237, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32445278

RESUMEN

Immunofluorescence microscopy is an essential tool for tissue-based research, yet data reporting is almost always qualitative. Quantification of images, at the per-cell level, enables "flow cytometry-type" analyses with intact locational data but achieving this is complex. Gastrointestinal tissue, for example, is highly diverse: from mixed-cell epithelial layers through to discrete lymphoid patches. Moreover, different species (e.g., rat, mouse, and humans) and tissue preparations (paraffin/frozen) are all commonly studied. Here, using field-relevant examples, we develop open, user-friendly methodology that can encompass these variables to provide quantitative tissue microscopy for the field. Antibody-independent cell labeling approaches, compatible across preparation types and species, were optimized. Per-cell data were extracted from routine confocal micrographs, with semantic machine learning employed to tackle densely packed lymphoid tissues. Data analysis was achieved by flow cytometry-type analyses alongside visualization and statistical definition of cell locations, interactions and established microenvironments. First, quantification of Escherichia coli passage into human small bowel tissue, following Ussing chamber incubations exemplified objective quantification of rare events in the context of lumen-tissue crosstalk. Second, in rat jejenum, precise histological context revealed distinct populations of intraepithelial lymphocytes between and directly below enterocytes enabling quantification in context of total epithelial cell numbers. Finally, mouse mononuclear phagocyte-T cell interactions, cell expression and significant spatial cell congregations were mapped to shed light on cell-cell communication in lymphoid Peyer's patch. Accessible, quantitative tissue microscopy provides a new window-of-insight to diverse questions in gastroenterology. It can also help combat some of the data reproducibility crisis associated with antibody technologies and over-reliance on qualitative microscopy. © 2020 The Authors. Cytometry Part A published by Wiley Periodicals LLC. on behalf of International Society for Advancement of Cytometry.


Asunto(s)
Gastroenterología , Ganglios Linfáticos Agregados , Animales , Citometría de Flujo , Humanos , Ratones , Microscopía , Ratas , Reproducibilidad de los Resultados
4.
Microbiome ; 8(1): 60, 2020 04 30.
Artículo en Inglés | MEDLINE | ID: mdl-32354347

RESUMEN

BACKGROUND: The multifaceted interactions between gastrointestinal (GI) helminth parasites, host gut microbiota and immune system are emerging as a key area of research within the field of host-parasite relationships. In spite of the plethora of data available on the impact that GI helminths exert on the composition of the gut microflora, whether alterations of microbial profiles are caused by direct parasite-bacteria interactions or, indirectly, by alterations of the GI environment (e.g. mucosal immunity) remains to be determined. Furthermore, no data is thus far available on the downstream roles that qualitative and quantitative changes in gut microbial composition play in the overall pathophysiology of parasite infection and disease. RESULTS: In this study, we investigated the fluctuations in microbiota composition and local immune microenvironment of sheep vaccinated against, and experimentally infected with, the 'brown stomach worm' Teladorsagia circumcincta, a parasite of worldwide socio-economic significance. We compared the faecal microbial profiles of vaccinated and subsequently infected sheep with those obtained from groups of unvaccinated/infected and unvaccinated/uninfected animals. We show that alterations of gut microbial composition are associated mainly with parasite infection, and that this involves the expansion of populations of bacteria with known pro-inflammatory properties that may contribute to the immunopathology of helminth disease. Using novel quantitative approaches for the analysis of confocal microscopy-derived images, we also show that gastric tissue infiltration of T cells is driven by parasitic infection rather than anti-helminth vaccination. CONCLUSIONS: Teladorsagia circumcincta infection leads to an expansion of potentially pro-inflammatory gut microbial species and abomasal T cells. This data paves the way for future experiments aimed to determine the contribution of the gut flora to the pathophysiology of parasitic disease, with the ultimate aim to design and develop novel treatment/control strategies focused on preventing and/or restricting bacterial-mediated inflammation upon infection by GI helminths. Video Abstract.


Asunto(s)
Bacterias/aislamiento & purificación , Heces/microbiología , Microbioma Gastrointestinal , Parasitosis Intestinales/veterinaria , Infecciones por Nematodos/veterinaria , Animales , Bacterias/clasificación , Ovinos , Trichostrongyloidea
5.
Med Sport Sci ; 62: 139-152, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28571033

RESUMEN

Prior to the formation of the World Anti-Doping Agency (WADA), the fight against doping in sport was not unified; instead, it relied on individual approaches established by various stakeholders to make it effective. The scandal of the Festina Affair, during the Tour de France 1998, and other drug doping scandals revealed the ineffectiveness and inadequacy of such an approach. The resulting media scandal raised public authorities' awareness about the necessity to deal with doping in sport with a harmonized and a more effective approach. The International Olympic Committee interceded and convened a World Conference on Doping, bringing together all parties involved in the fight against doping. As a result, WADA was established on November 10, 1999, in Lausanne to promote and coordinate the fight against doping in sport internationally. In this regard, the World Anti-Doping Code (WADC or the Code) is the core document harmonizing anti-doping rules and regulations within sport organizations and public authorities. The Code was instrumental in introducing the concept of "nonanalytical" rule violations, which are emphasized within the revised 2015 Code. Nonanalytical rule violations allow anti-doping organizations (ADOs) to apply sanctions in cases where there is no positive doping sample, but where there may still be evidence that a doping violation has occurred. This recognition of "nonanalytical" rule violations by WADA is the concrete result of taking into account lessons learned from prior infamous doping scandals. Thus, intelligence gathering, particularly through cooperation with global law enforcement agencies, is a key tool in the fight against doping. The 2015 Code and the international standards on testing and investigations establish and implement intelligence gathering as part of ADOs' routine activities in the fight against doping in sport.


Asunto(s)
Doping en los Deportes/prevención & control , Detección de Abuso de Sustancias/métodos , Recolección de Datos , Humanos , Cooperación Internacional , Detección de Abuso de Sustancias/normas
6.
Front Immunol ; 8: 284, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28367148

RESUMEN

Naturally occurring intestinal nanomineral particles constituently form in the mammalian gut and trap luminal protein and microbial components. These cargo loaded nanominerals are actively scavenged by M cells of intestinal immune follicles, such as Peyer's patches and are passed to antigen-presenting cells. Using peripheral blood mononuclear cell populations as an in vitro model of nanomineral uptake and antigen presentation, we show that monocytes avidly phagocytose nanomineral particles bearing antigen and peptidoglycan (PGN), and that the presence of PGN within particles downregulates their cell surface MHC class II and upregulates programmed death receptor ligand 1. Nanomineral delivery of antigen suppresses antigen-specific CD4+ T cell responses, an effect that is enhanced in the presence of PGN. Blocking the interleukin-10 receptor restores CD4+ T cell responses to antigen codelivered with PGN in nanomineral form. Using human intestinal specimens, we have shown that the in vivo nanomineral pathway operates in an interleukin-10 rich environment. Consequently, the delivery of a dual antigen-PGN cargo by endogenous nanomineral in vivo is likely to be important in the establishment of intestinal tolerance, while their synthetic mimetics present a potential delivery system for therapeutic applications targeting the modulation of Peyer's patch T cell responses.

7.
Am J Physiol Cell Physiol ; 312(5): C550-C561, 2017 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-28179233

RESUMEN

Silicon (Si) has long been known to play a major physiological and structural role in certain organisms, including diatoms, sponges, and many higher plants, leading to the recent identification of multiple proteins responsible for Si transport in a range of algal and plant species. In mammals, despite several convincing studies suggesting that silicon is an important factor in bone development and connective tissue health, there is a critical lack of understanding about the biochemical pathways that enable Si homeostasis. Here we report the identification of a mammalian efflux Si transporter, namely Slc34a2 (also termed NaPiIIb), a known sodium-phosphate cotransporter, which was upregulated in rat kidney following chronic dietary Si deprivation. Normal rat renal epithelium demonstrated punctate expression of Slc34a2, and when the protein was heterologously expressed in Xenopus laevis oocytes, Si efflux activity (i.e., movement of Si out of cells) was induced and was quantitatively similar to that induced by the known plant Si transporter OsLsi2 in the same expression system. Interestingly, Si efflux appeared saturable over time, but it did not vary as a function of extracellular [Formula: see text] or Na+ concentration, suggesting that Slc34a2 harbors a functionally independent transport site for Si operating in the reverse direction to the site for phosphate. Indeed, in rats with dietary Si depletion-induced upregulation of transporter expression, there was increased urinary phosphate excretion. This is the first evidence of an active Si transport protein in mammals and points towards an important role for Si in vertebrates and explains interactions between dietary phosphate and silicon.


Asunto(s)
Fosfatos/metabolismo , Silicio/metabolismo , Proteínas Cotransportadoras de Sodio-Fosfato de Tipo IIb/química , Proteínas Cotransportadoras de Sodio-Fosfato de Tipo IIb/metabolismo , Sodio/metabolismo , Animales , Femenino , Ratas , Ratas Sprague-Dawley , Especificidad de la Especie
8.
Nanomedicine ; 13(2): 619-630, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27478107

RESUMEN

Amorphous magnesium-substituted calcium phosphate (AMCP) nanoparticles (75-150nm) form constitutively in large numbers in the mammalian gut. Collective evidence indicates that they trap and deliver luminal macromolecules to mucosal antigen presenting cells (APCs) and facilitate gut immune homeostasis. Here, we report on a synthetic mimetic of the endogenous AMCP and show that it has marked capacity to trap macromolecules during formation. Macromolecular capture into AMCP involved incorporation as shown by STEM tomography of the synthetic AMCP particle with 5nm ultra-fine iron (III) oxohydroxide. In vitro, organic cargo-loaded synthetic AMCP was taken up by APCs and tracked to lysosomal compartments. The AMCP itself did not regulate any gene, or modify any gene regulation by its cargo, based upon whole genome transcriptomic analyses. We conclude that synthetic AMCP can efficiently trap macromolecules and deliver them to APCs in a silent fashion, and may thus represent a new platform for antigen delivery.


Asunto(s)
Células Presentadoras de Antígenos , Sustancias Macromoleculares , Nanopartículas , Animales , Antígenos , Citoplasma
9.
Sci Rep ; 6: 26747, 2016 05 26.
Artículo en Inglés | MEDLINE | ID: mdl-27226337

RESUMEN

Crohn's disease is a chronic inflammatory condition most commonly affecting the ileum and colon. The aetiology of Crohn's disease is complex and may include defects in peptidoglycan recognition, and/or failures in the establishment of intestinal tolerance. We have recently described a novel constitutive endogenous delivery system for the translocation of nanomineral-antigen-peptidoglycan (NAP) conjugates to antigen presenting cells (APCs) in intestinal lymphoid patches. In mice NAP conjugate delivery to APCs results in high surface expression of the immuno-modulatory molecule programmed death receptor ligand 1 (PD-L1). Here we report that NAP conjugate positive APCs in human ileal tissues from individuals with ulcerative colitis and intestinal carcinomas, also have high expression of PD-L1. However, NAP-conjugate positive APCs in intestinal tissue from patients with Crohn's disease show selective failure in PD-L1 expression. Therefore, in Crohn's disease intestinal antigen taken up by lymphoid patch APCs will be presented without PD-L1 induced tolerogenic signalling, perhaps initiating disease.


Asunto(s)
Células Presentadoras de Antígenos/inmunología , Antígeno B7-H1/inmunología , Enfermedad de Crohn/inmunología , Regulación de la Expresión Génica/inmunología , Intestinos/inmunología , Células Presentadoras de Antígenos/patología , Antígeno B7-H1/biosíntesis , Enfermedad de Crohn/metabolismo , Enfermedad de Crohn/patología , Femenino , Humanos , Mucosa Intestinal/metabolismo , Intestinos/patología , Masculino
10.
Nat Nanotechnol ; 10(4): 361-9, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25751305

RESUMEN

In humans and other mammals it is known that calcium and phosphate ions are secreted from the distal small intestine into the lumen. However, why this secretion occurs is unclear. Here, we show that the process leads to the formation of amorphous magnesium-substituted calcium phosphate nanoparticles that trap soluble macromolecules, such as bacterial peptidoglycan and orally fed protein antigens, in the lumen and transport them to immune cells of the intestinal tissue. The macromolecule-containing nanoparticles utilize epithelial M cells to enter Peyer's patches, small areas of the intestine concentrated with particle-scavenging immune cells. In wild-type mice, intestinal immune cells containing these naturally formed nanoparticles expressed the immune tolerance-associated molecule 'programmed death-ligand 1', whereas in NOD1/2 double knockout mice, which cannot recognize peptidoglycan, programmed death-ligand 1 was undetected. Our results explain a role for constitutively formed calcium phosphate nanoparticles in the gut lumen and show how this helps to shape intestinal immune homeostasis.


Asunto(s)
Antígenos/inmunología , Intestinos/citología , Intestinos/inmunología , Peptidoglicano/inmunología , Ganglios Linfáticos Agregados/inmunología , Fosfatos/inmunología , Animales , Calcio/inmunología , Fosfatos de Calcio/inmunología , Células Cultivadas , Humanos , Intestinos/química , Ratones , Ratones Endogámicos BALB C , Minerales/inmunología , Chaperonas Moleculares/inmunología , Nanopartículas/química , Nanopartículas/ultraestructura , Tamaño de la Partícula , Ganglios Linfáticos Agregados/citología
11.
PLoS One ; 7(9): e43538, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22957029

RESUMEN

Feral pigs (Sus scrofa) are an invasive species that disrupt ecosystem functioning throughout their introduced range. In tropical environments, feral pigs are associated with predation and displacement of endangered species, modification of habitat, and act as a vector for the spread of exotic vegetation and disease. Across many parts of their introduced range, the diet of feral pigs is poorly known. Although the remote location and difficult terrain of far north Queensland makes observing feral pig behavior difficult, feral pigs are perceived to seek refuge in World Heritage tropical rainforests and seasonally 'crop raid' into lowland sugarcane crops. Thus, identifying how feral pigs are using different components of the landscape is important to the design of management strategies. We used the stable isotope composition of captured feral pigs to determine the extent of rainforest and sugarcane habitat usage. Recently grown hair (basal hair) from feral pigs captured in remote rainforest indicated pigs met their dietary needs solely within this habitat. Stable carbon and nitrogen isotope values of basal hair from feral pigs captured near sugarcane plantations were more variable, with some individuals estimated to consume over 85% of their diet within a sugarcane habitat, while a few consumed as much as 90% of their diet from adjacent forested environments. We estimated whether feral pigs switch habitats by sequentially sampling δ(13)C and δ(15)N values of long tail hair from a subset of seven captured animals, and demonstrate that four of these individuals moved between habitats. Our results indicate that feral pigs utilize both sugarcane and forest habitats, and can switch between these resources.


Asunto(s)
Ecosistema , Cabello/metabolismo , Saccharum/metabolismo , Alimentación Animal , Animales , Isótopos de Carbono/análisis , Conducta Alimentaria , Geografía , Especies Introducidas , Isótopos/análisis , Isótopos de Nitrógeno/análisis , Queensland , Porcinos , Clima Tropical
13.
Altern Ther Health Med ; 10(3): 70-2, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-15154155

RESUMEN

CONTEXT: Magnetic fields have been found to affect neuromuscular function. OBJECTIVE: To study the effect of a magnetic field on measurements of urethral function in women with stress urinary incontinence. DESIGN: Observational comparative study. SETTING: Consecutive patients in a continence center. PATIENTS OR OTHER PARTICIPANTS: Twenty-six consecutive women with diagnosis of stress urinary incontinence (SUI). EVALUATION: History and physical examination, neurologic exam, urethrocystoscopy, urodynamic testing with water-filling cystometry, urethral profilometry at rest, during coughing, and during coughing while performing a levator ani contraction (knack maneuver). INTERVENTION: The same urodynamic procedures were performed again after the subjects were asked to step on specifically designed magnets (magnetic cushion device). STATISTICAL ANALYSIS: Two-tailed student t test. MAIN OUTCOME MEASURES: Urethral pressure at rest, during coughing, and during coughing while performing a levator ani contraction. RESULTS: Mean age was 58.3 years (range: 36-81), mean parity 2.8 (range: 0-8). The urodynamic parameters measured without and with the use of the magnetic cushion device were not found to be different except for the knack maneuver. The pressure in the urethra during the knack maneuver while the subjects were stepping on the magnetic device was significantly higher than the 1 obtained without the magnetic field. CONCLUSION: In our patient population, a magnetic field increases the efficacy of voluntary levator ani contractions.


Asunto(s)
Magnetismo , Contracción Muscular , Diafragma Pélvico/fisiopatología , Uretra/fisiopatología , Incontinencia Urinaria de Esfuerzo , Urodinámica , Adulto , Anciano , Anciano de 80 o más Años , California , Femenino , Humanos , Masculino , Persona de Mediana Edad , Músculo Esquelético/inervación , Factores de Tiempo , Incontinencia Urinaria de Esfuerzo/diagnóstico , Incontinencia Urinaria de Esfuerzo/fisiopatología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...