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BACKGROUND: There continues to be uncertainty about the optimal approach to documenting bleeding data in platelet transfusion trials, with a desire to apply a common assessment tool across all trials. With this in mind, a consensus bleeding assessment tool (BAT) has been developed by the Biomedical Excellence for Safer Transfusion (BEST) collaborative, based on review of data collection forms used in published randomized trials and following content validation with a range of healthcare professionals at seven haematology centres through BEST members. This study aimed to evaluate reliability and reproducibility of the consensus BAT. METHODS: Replicated clinical assessments of bleeding were undertaken by participants with haematological malignancies recruited at four haematology centres in an international, multicentred, observational study. Concordance of repeat assessments was calculated for agreement in site and grade of bleeding observed. RESULTS: Forty patients consented to participate, and 13 trained bleeding assessors collected these data. Bleeding assessments were carried out on 113 separate days. Of all 225 bleeding assessments, 204 were compared for grade concordance, and 160 were compared for site concordance. There was very good grade concordance (83%, 95% confidence interval 74-93%) and good bleeding site concordance (69%, 95% confidence interval 57-79%) in observations of bleeding. Discordance was primarily in relation to assessing skin bleeding. CONCLUSIONS: Alongside a structured training programme, levels of concordance for a consensus BAT were high. Researchers using assessment tools for bleeding need to balance comprehensive data collection against potential loss of accuracy for some types of bleeding, such as skin findings.
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Neoplasias Hematológicas/terapia , Hemorragia/patología , Transfusión de Plaquetas/normas , Adulto , Femenino , Hemorragia/epidemiología , Hemorragia/etiología , Humanos , Masculino , Transfusión de Plaquetas/efectos adversos , Reproducibilidad de los ResultadosRESUMEN
Experiences of mobile pastoralists often attest to a wide range of contradictions about the presumed advantages of formal education. While effort to 'reach' pastoralists has intensified under the global Education for All movement, there remain considerable difficulties in finding ways to make formal education relate to pastoralist livelihoods and complement endogenous knowledge. This paper examines how these dynamics play out across models of formal and non-formal education service provision, and identifies innovations that offer promising ways forward: Alternative Basic Education, Open and Distance Learning, and Pastoralist Field Schools.
Les expériences rapportées par les pasteurs nomades témoignent souvent de contradictions diverses concernant les avantages présumés de l'éducation formelle. Les efforts visant à proposer une offre adaptée aux pasteurs se sont intensifiés dans le cadre du mouvement de l'Éducation pour tous mais se heurtent à la difficulté d'élaborer des solutions d'éducation formelle en lien avec les moyens de subsistance du pastoralisme et complétant les savoirs endogènes. L'auteur examine l'évolution de ces dynamiques dans différents modèles d'offres d'éducation formelle et non formelle et identifie trois champs d'innovation qui lui paraissent prometteurs pour l'avenir : l'Enseignement élémentaire alternatif, l'apprentissage ouvert et à distance et les écoles pastorales de terrain.
La experiencia de los grupos pastorales nómadas suele evidenciar muy diversas contradicciones que ponen en tela de juicio las presuntas ventajas de la educación formal. Como parte del movimiento mundial en pro de la Educación para Todos se han redoblado esfuerzos para «llegar¼ a los grupos de pastores, pero aun así subsisten considerables dificultades a la hora de encontrar fórmulas para impartirles una enseñanza que guarde relación con sus medios de sustento y venga a completar los conocimientos endógenos. La autora examina el modo en que esta dinámica se articula con los modelos de prestación de servicios educativos formales y no formales y describe innovaciones que abren vías prometedoras: la educación básica alternativa, el aprendizaje abierto y a distancia o las escuelas de campo pastorales.
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Crianza de Animales Domésticos/métodos , Educación/métodos , Modelos Educacionales , Instituciones Académicas/clasificación , Crianza de Animales Domésticos/educación , Animales , Educación/normas , Humanos , Dinámica Poblacional , Instituciones Académicas/tendenciasRESUMEN
Apolipoprotein L-1 (APOL1) gene variants are associated with end-stage renal disease in African Americans (AAs). Here we investigate the impact of recipient APOL1 gene distributions on kidney allograft outcomes. We conducted a retrospective analysis of 119 AA kidney transplant recipients, and found that 58 (48.7%) carried two APOL1 kidney disease risk variants. Contrary to the association seen in native kidney disease, there is no difference in allograft survival at 5-year posttransplant for recipients with high-risk APOL1 genotypes. Thus, we were able to conclude that APOL1 genotypes do not increase risk of allograft loss after kidney transplantations, and carrying 2 APOL1 risk alleles should not be an impediment to transplantation.
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Apolipoproteínas/genética , Población Negra/genética , Supervivencia de Injerto/genética , Trasplante de Riñón , Lipoproteínas HDL/genética , Adulto , Apolipoproteína L1 , Genotipo , Humanos , Persona de Mediana EdadRESUMEN
Early development of the microbiome has been shown to affect general health and physical development of the infant and, although some studies have been undertaken in high-income countries, there are few studies from low- and middle-income countries. As part of the BARNARDS study, we examined the rectal microbiota of 2,931 neonates (term used up to 60 d) with clinical signs of sepsis and of 15,217 mothers screening for blaCTX-M-15, blaNDM, blaKPC and blaOXA-48-like genes, which were detected in 56.1%, 18.5%, 0% and 4.1% of neonates' rectal swabs and 47.1%, 4.6%, 0% and 1.6% of mothers' rectal swabs, respectively. Carbapenemase-positive bacteria were identified by MALDI-TOF MS and showed a high diversity of bacterial species (57 distinct species/genera) which exhibited resistance to most of the antibiotics tested. Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae/E. cloacae complex, the most commonly found isolates, were subjected to whole-genome sequencing analysis and revealed close relationships between isolates from different samples, suggesting transmission of bacteria between neonates, and between neonates and mothers. Associations between the carriage of antimicrobial resistance genes (ARGs) and healthcare/environmental factors were identified, and the presence of ARGs was a predictor of neonatal sepsis and adverse birth outcomes.
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Microbioma Gastrointestinal , Sepsis , Antibacterianos , Países en Desarrollo , Farmacorresistencia Microbiana , Escherichia coli , Femenino , Humanos , Lactante , Recién Nacido , Pruebas de Sensibilidad Microbiana , MadresRESUMEN
This is the first study to provide evidence that one function for the surface glycolipid galactocerebroside (GalC) is participation in the opening of Ca2+ channels in oligodendroglia in culture. This glycolipid is a unique differentiation marker for myelin-producing cells; antibodies to GalC have been shown to markedly alter oligodendroglial morphology via disruption of microtubules (Dyer, C. A., and J. A. Benjamins. 1988. J. Neurosci. 8:4307-4318). This study demonstrates that extracellular EGTA blocks anti-GalC-induced disassembly of microtubules in oligodendroglial membrane sheets, demonstrating that an influx of extracellular Ca2+ mediates the cytoskeletal changes. The Ca2+ influx was examined directly by loading oligodendroglia with the fluorescent dye Indo-1 in defined medium, and measuring changes in Ca2+ in individual cells with a laser cytometer. Upon addition of anti-GalC IgG, a marked sustained increase in intracellular Ca2+ occurred in 80% of the oligodendroglia observed. EGTA blocked the increase, indicating the increase is due to an influx of extracellular Ca2+, and not due to release from intracellular stores. The effect is specific, since Ca2+ levels remain normal in oligodendroglia treated with nonimmune IgG; astrocytes do not respond to the anti-GalC. The Ca2+ response in oligodendrocytes is dependent on concentration of antibody and GalC on the oligodendroglial membrane surface. The Ca2+ influx is not mediated by voltage-sensitive Ca2+ channels: it is not blocked by cadmium, and depolarization with K+ does not mimic the response. The kinetics of the response suggest that second messenger-mediated opening of Ca2+ channels is involved.
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Anticuerpos , Calcio/metabolismo , Cerebrósidos/fisiología , Galactosilceramidas/fisiología , Lípidos de la Membrana/fisiología , Oligodendroglía/fisiología , Transducción de Señal , Animales , Animales Recién Nacidos , Encéfalo/fisiología , Encéfalo/ultraestructura , Calcio/farmacología , Canales de Calcio/fisiología , Membrana Celular/fisiología , Membrana Celular/ultraestructura , Células Cultivadas , Ácido Egtácico/farmacología , Galactosilceramidas/inmunología , Masculino , Lípidos de la Membrana/inmunología , Ratones , Microtúbulos/ultraestructura , Oligodendroglía/efectos de los fármacos , Oligodendroglía/ultraestructuraRESUMEN
Dose assessment procedures for cosmic radiation exposure of aircraft crew have been introduced in most European countries in accordance with the corresponding European directive and national regulations. However, the radiation exposure due to solar particle events is still a matter of scientific research. Here we describe the European research project CONRAD, WP6, Subgroup-B, about the current status of available solar storm measurements and existing models for dose estimation at flight altitudes during solar particle events leading to ground level enhancement (GLE). Three models for the numerical dose estimation during GLEs are discussed. Some of the models agree with limited experimental data reasonably well. Analysis of GLEs during geomagnetically disturbed conditions is still complex and time consuming. Currently available solar particle event models can disagree with each other by an order of magnitude. Further research and verification by on-board measurements is still needed.
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Aeronaves , Altitud , Radiación Cósmica , Modelos Teóricos , Dosis de Radiación , Actividad Solar , Humanos , Exposición Profesional , Monitoreo de RadiaciónRESUMEN
[This corrects the article DOI: 10.1063/1.4964813.].
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Factors that modulate the ability of monosodium urate crystals to stimulate leukocytes could regulate gouty inflammation. Lipoproteins that bear apo B-100 and apo E bind to urate crystals and suppress crystal-neutrophil interaction. In this study, we observed that urate crystals, coated with apo E of monocyte origin, had a diminished ability to stimulate neutrophils. Apo E was also detected on the surface of urate crystals recovered from gout patients. Thus, we analyzed apo E in noninflammatory synovial fluid, and found it to be associated with particles of heterogeneous size and of predominantly alpha and pre-beta electrophoretic mobility. Local articular synthesis of at least a portion of synovial fluid apo E was suggested because (a) the synovial fluid/plasma concentration ratio of apo E was significantly higher than that for both apo B and apo A-I, which are not widely synthesized by extrahepatic tissues, (b) cultured rheumatoid synovial cells in first passage secreted apo E, (c) a portion of synovial fluid apo E was heavily sialylated. We conclude that synovial fluids contain apo E that appears partly of local origin. Apo E binds to urate crystals and could modulate gouty inflammation.
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Apolipoproteínas E/fisiología , Neutrófilos/efectos de los fármacos , Líquido Sinovial/química , Ácido Úrico/antagonistas & inhibidores , Apolipoproteínas E/metabolismo , Cartílago/metabolismo , Cristalización , Gota/metabolismo , Humanos , Neutrófilos/fisiología , Ácido Úrico/metabolismoRESUMEN
Cytokines are known to have both stimulatory and inhibitory effects on breast cancer growth depending on their relative concentrations and the presence of other modulating factors in the tumour microenvironment. Certain cytokines appear to prevent an effective immune response being mounted, permitting cancer growth, whereas others promote the immune system's anti-tumour capability. Furthermore, the systemic levels of certain cytokines, e.g. IL-6 and IL-18, independently show promising correlations with disease stage and progression. With advances in methods for delivery of cytokines to a tumour site, the enhanced induction of anti-tumour immunity by targeted cytokine release is becoming a realistic option. Here, we review the role of cytokines in the immune response against breast cancer and assess their potential as prognostic indicators and/or use in immune therapy. A literature search was conducted using Medline, restricted to articles published in the English language, using combinations of the following MeSH terms: cytokines, breast cancer, immunology, immunotherapy and interleukins. Focused searches using keywords relevant to the role of cytokines in breast cancer immunology yielded >200 references.
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Neoplasias de la Mama/diagnóstico , Neoplasias de la Mama/tratamiento farmacológico , Citocinas/análisis , Citocinas/uso terapéutico , Biomarcadores de Tumor/análisis , Neoplasias de la Mama/inmunología , Femenino , Humanos , PronósticoRESUMEN
Synchronisation, using a combination of gonadotrophin-releasing hormone and prostaglandin F2alpha injections, is commonly used to control the reproductive cycle of dairy cows. A simple model that could predict the monetary return from synchronisation would be a valuable tool in determining whether it would be worthwhile. This study used data from three controlled clinical trials to investigate the effects of six factors (interval between calving and synchronisation, 21-day submission rate, number of cows synchronised, average age, pregnancy rate of non-synchronised cows and season) on the return from synchronisation. The results suggests that the herd's submission and pregnancy rates, the time between calving and synchronisation, and the number of cows synchronised can all significantly affect the return from synchronisation, but only time since calving significantly affected the return in all three trials. They also suggest that there is no simple linear relationship between these factors and the return from synchronisation.
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Bovinos/fisiología , Industria Lechera/economía , Dinoprost/farmacología , Sincronización del Estro , Fármacos para la Fertilidad Femenina/farmacología , Hormona Liberadora de Gonadotropina/farmacología , Factores de Edad , Animales , Análisis Costo-Beneficio , Industria Lechera/métodos , Dinoprost/economía , Femenino , Fármacos para la Fertilidad Femenina/economía , Hormona Liberadora de Gonadotropina/economía , Embarazo , Índice de Embarazo , Estaciones del Año , Factores de TiempoRESUMEN
The study of inflammatory bowel disease, including Ulcerative Colitis and Crohn's Disease, has relied largely upon the use of animal or cell culture models; neither of which can represent all aspects of the human pathophysiology. Presented herein is a dual flow microfluidic device which holds full thickness human intestinal tissue in a known orientation. The luminal and serosal sides are independently perfused ex vivo with nutrients with simultaneous waste removal for up to 72 h. The microfluidic device maintains the viability and integrity of the tissue as demonstrated through Haematoxylin & Eosin staining, immunohistochemistry and release of lactate dehydrogenase. In addition, the inflammatory state remains in the tissue after perfusion on the device as determined by measuring calprotectin levels. It is anticipated that this human model will be extremely useful for studying the biology and testing novel interventions in diseased tissue.
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The kinetic rates and equilibrium association constants for cyanide binding have been measured for a series of cytochrome c derivatives as a probe of heme accessibility. The series included horse and yeast cytochromes iodinated at Tyr 67 and 74, horse cytochrome formylated at Trp 59 in both a low and high redox potential form, the Met 80 sulfoxide derivative of horse cytochrome and the N-acylisourea heme propionate derivative of tuna cytochrome. Native cytochromes c are well known to bind cyanide slowly in a reaction simply first order both in cytochrome and cyanide up to at least 100 mM in cyanide. The derivative demonstrate markedly different kinetics which indicate the following conclusions. (1) In spite of chemical modification at different loci, all the derivatives have highly similar reactivity, suggesting common ligation structures and mechanisms for reaction. (2) Compared to native cytochromes, reaction rates are 10-20 fold greater. This is in accord with a more accessible heme crevice, but not a completely opened crevice. For the completely opened case, rate increases are expected to be between three and five orders of magnitude. (3) Reaction rates are either independent of cyanide concentration (zero order) or show only slight variation. A mechanism which accounts for the data over four orders of magnitude in concentration postulates a protein conformation step, opening of the heme crevice, as the rate determining step. This conformation change has a limiting rate of 6 . 10(-2) s-1.
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Cianuros , Grupo Citocromo c , Animales , Fenómenos Químicos , Química , Caballos , Cinética , Ligandos , Unión Proteica , Conformación Proteica , Saccharomyces cerevisiaeRESUMEN
Apolipoprotein-E (apoE) is a constituent of various lipoproteins and is a ligand for cellular lipoprotein receptors. Unlike most apolipoproteins, apoE is synthesized in peripheral tissues, including those engaged in steroidogenesis. ApoE expression in adrenal cells inhibits cholesterol utilization for steroid synthesis and blocks signal transduction via the protein kinase-A pathway. In cultured ovarian thecal/interstitial cells, exogenous apoE has been shown to inhibit LH-induced androgen synthesis. These findings support a role for apoE as an autocrine or paracrine factor involved in regulating steroidogenesis. In the present study in situ hybridization was used to identify cell types that express apoE mRNA in ovaries from rats with a 4-day estrous cycle, from pregnant rats, from immature rats treated with PMSG to stimulate follicular development, and from PMSG-treated rats that were subsequently administered hCG to stimulate ovulation and luteinization. ApoE mRNA was localized to theca and interstitial cells of follicles in animals at all stages of the estrous cycle as well as in immature rats treated with PMSG. ApoE mRNA was not detected in oocytes, cumulus cells, or granulosa cells. High levels of apoE mRNA also were expressed by localized clusters of presumptive macrophages in atretic follicles and degenerating corpora lutea. This complex pattern of expression may indicate that apoE has multiple functions in the rat ovary. ApoE made by theca and interstitial cells may act locally as an autocrine factor to regulate androgen production. ApoE made in atretic follicles and regressing corpora lutea may serve to facilitate local transport and reutilization of lipid released as these structures degenerate.
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Apolipoproteínas E/biosíntesis , Células de la Granulosa/metabolismo , Macrófagos/metabolismo , Ovario/citología , Células Tecales/metabolismo , Animales , Apolipoproteínas E/genética , Apolipoproteínas E/fisiología , Northern Blotting , Células Cultivadas , Gonadotropina Coriónica/farmacología , Cuerpo Lúteo/metabolismo , Estro , Femenino , Expresión Génica/efectos de los fármacos , Gonadotropinas Equinas/farmacología , Hibridación de Ácido Nucleico , Folículo Ovárico/metabolismo , Ovario/metabolismo , Inducción de la Ovulación , Embarazo , ARN Mensajero/biosíntesis , Ratas , Ratas EndogámicasRESUMEN
Multifractal analysis techniques are applied to patterns in several abstract expressionist artworks, painted by various artists. The analysis is carried out on two distinct types of structures: the physical patterns formed by a specific color ("blobs") and patterns formed by the luminance gradient between adjacent colors ("edges"). It is found that the multifractal analysis method applied to "blobs" cannot distinguish between artists of the same movement, yielding a multifractal spectrum of dimensions between about 1.5 and 1.8. The method can distinguish between different types of images, however, as demonstrated by studying a radically different type of art. The data suggest that the "edge" method can distinguish between artists in the same movement and is proposed to represent a toy model of visual discrimination. A "fractal reconstruction" analysis technique is also applied to the images in order to determine whether or not a specific signature can be extracted which might serve as a type of fingerprint for the movement.
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We conducted an on-line search and manual searches for 1966 through 1992 to determine the incidence, diagnosis, risk factors, and treatment of postoperative delirium. Of the 374 citations found, 277 articles were excluded after criteria of relevance were applied. After methodologic criteria for validity were applied to the remaining 80 articles, 26 studies were retained for the final information synthesis. The incidence of postoperative delirium was 36.8% (range, 0% to 73.5%). Primary reasons for this disparity were insufficient sample size and inconsistent application of numerous diagnostic tools. One study provided statistically significant data that demonstrated that postoperative delirium is underdiagnosed by physicians and nurses. Four of the articles that met the established criteria provided risk factor data. Although age, preoperative cognitive impairment, and the use of anticholinergic drugs were significantly associated with postoperative delirium, gender, type and route of anesthesia, and sleep deprivation were not. Two studies demonstrated a decreased incidence of postoperative delirium when patients underwent preoperative psychiatric counseling or participated in a structured perioperative program. These findings indicate a need for (1) accurate incidence data with further definition of risk factors and (2) studies that address the diagnosis and treatment of this common postoperative problem.
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Delirio , Complicaciones Posoperatorias , Delirio/diagnóstico , Delirio/epidemiología , Delirio/etiología , Delirio/terapia , Diagnóstico Diferencial , Humanos , Incidencia , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/terapia , Factores de RiesgoRESUMEN
OBJECTIVES: Data on costs associated with acute upper gastrointestinal bleeding (AUGIB) are scarce. We provide estimates of UK healthcare costs, indirect costs and health-related quality of life (HRQoL) for patients presenting to hospital with AUGIB. SETTING: Six UK university hospitals with >20 AUGIB admissions per month, >400 adult beds, 24â h endoscopy, and on-site access to intensive care and surgery. PARTICIPANTS: 936 patients aged ≥18â years, admitted with AUGIB, and enrolled between August 2012 and March 2013 in the TRIGGER trial of AUGIB comparing restrictive versus liberal red blood cell (RBC) transfusion thresholds. PRIMARY AND SECONDARY OUTCOME MEASURES: Healthcare resource use during hospitalisation and postdischarge up to 28â days, unpaid informal care, time away from paid employment and HRQoL using the EuroQol EQ-5D at 28â days were measured prospectively. National unit costs were used to value resource use. Initial in-hospital treatment costs were upscaled to a UK level. RESULTS: Mean initial in-hospital costs were £2458 (SE=£216) per patient. Inpatient bed days, endoscopy and RBC transfusions were key cost drivers. Postdischarge healthcare costs were £391 (£44) per patient. One-third of patients received unpaid informal care and the quarter in paid employment required time away from work. Mean HRQoL for survivors was 0.74. Annual initial inhospital treatment cost for all AUGIB cases in the UK was estimated to be £155.5 million, with exploratory analyses of the incremental costs of treating hospitalised patients developing AUGIB generating figures of between £143 million and £168 million. CONCLUSIONS: AUGIB is a large burden for UK hospitals with inpatient stay, endoscopy and RBC transfusions as the main cost drivers. It is anticipated that this work will enable quantification of the impact of cost reduction strategies in AUGIB and will inform economic analyses of novel or existing interventions for AUGIB. TRIAL REGISTRATION NUMBER: ISRCTN85757829 and NCT02105532.
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Endoscopía/economía , Transfusión de Eritrocitos/economía , Hemorragia Gastrointestinal/economía , Costos de la Atención en Salud , Hospitalización/economía , Calidad de Vida , Enfermedad Aguda , Análisis Costo-Beneficio , Endoscopía/estadística & datos numéricos , Transfusión de Eritrocitos/estadística & datos numéricos , Hemorragia Gastrointestinal/epidemiología , Hemorragia Gastrointestinal/psicología , Hospitalización/estadística & datos numéricos , Humanos , Tiempo de Internación/economía , Estudios Prospectivos , Reino Unido/epidemiologíaRESUMEN
The MOCH-1 glial cell line, which was derived from a glioblastoma taken from the brain of a MBP/c-neu transgenic mouse, was used as a model for studying the plastic nature of gliomas in culture. Fifteen MOCH-1 clones were derived and characterized under different growth conditions via Western blot analysis and immunocytochemical staining using a panel of antibodies specific for major myelin markers and glial fibrillary acidic protein. In low serum conditions, the clones resemble immature oligodendrocytes and express only immature oligodendrocyte markers. When placed in serum-free chemically defined medium (CDM), nine clones do not change their phenotypes, while five variably express myelin markers. One clone, 4C8, differentiates into mature, membrane sheet-bearing oligodendrocyte-like cells and expresses major myelin markers in amounts and distributions similar to cultured primary oligodendrocytes. Our data show that 4C8 can reversibly switch from an oligodendrocyte-like phenotype to a reactive astrocyte-like phenotype, depending upon the presence of serum and other factors in different growth media. Our data indicate that serum "pushes" 4C8 into the astrocyte-like phenotype, while serum-free CDM "pushes" 4C8 into the oligodendrocyte-like phenotype. Furthermore, a population of mixed phenotypes results when the astrocyte-like 4C8 cells are placed in serum-free CDM. To our knowledge, this is the first report to show that by altering environment, a "mixed glioma" can arise from a homogeneous population of glial tumor cells. It is therefore possible that glial tumor cells in vivo may be induced to undergo similar phenotypic changes when they are exposed to different environmental signals in the central nervous system.
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Astrocitos/fisiología , Clonación Molecular , Glioma/genética , Oligodendroglía/inmunología , Animales , Astrocitos/inmunología , Western Blotting , Células Cultivadas , Glioma/inmunología , Inmunohistoquímica , Ratones , Ratones Transgénicos , FenotipoRESUMEN
Phenylketonuria (PKU) is caused by mutation(s) in the phenylalanine hydroxylase (PAH) gene which lead to deficient PAH activity and an accumulation of phenylalanine in the blood. The primary pathologic finding is hypomyelination and gliosis of central nervous system white matter. Similar white matter pathology is observed in the Pahenu2 mouse, a genetic model for PKU. We studied this mouse to examine the basis for these neuropathologic changes in PKU and to determine if hypomyelination and gliosis occur independently or are interrelated. Although white matter tracts within PKU brains are hypomyelinated, immunostaining and Western blot analyses revealed that these tracts contain abundant amounts of myelin markers, i.e. myelin basic protein (MBP), 2',3'-cyclic nucleotide 3'phosphohydrolase, and myelin/oligodendrocyte-specific protein (MOSP). However, Western blot analyses also showed that MBP isoform expression was aberrant. Investigation of individual cells was performed by extraction of tissue sections with Triton X-100. Most of the MOSP was extracted, with the remaining MOSP clearly visible in dual labeled cells, i.e. MOSP was colocalized along glial fibrillary acidic protein (GFAP) filaments. Cells expressing both MBP and GFAP were also identified in optic tract. Double labeling with a riboprobe for MBP and antibodies specific for GFAP revealed that the majority of GFAP-positive cells expressed MBP mRNA. Our in vitro studies examined the response of cultured wild type oligodendrocytes to elevated phenylalanine for 4 weeks (wk). Under these conditions, about 50 these conditions, about 50% of the oligodendrocytes expressed GFAP filaments and failed to elaborate membrane sheets. Proliferation of astrocytes appears not to be the source of gliosis, since the nuclei of GFAP-positive cells in the PKU brains did not immunostain for proliferating cell nuclear antigen. Dual-labeled cells were detected in normal mouse brain sections; however, PKU mouse white matter tracts were found to contain about twice the number of dual-labeled cells compared to normal tissue. Taken together, these data suggest that both myelinating and nonmyelinating oligodendrocytes are present in the normal adult brain, and that in response to a toxic factor such as elevated phenylalanine, myelinating oligodendrocytes adopt a nonmyelinating phenotype that expresses GFAP. Since myelinating Schwann cells and GFAP-positive nonmyelinating Schwann cells are normally present in adult peripheral nerve, and the myelinating Schwann cells react to pathologic situations by switching to GFAP-positive nonmyelinating cells, it may be that oligodendrocytes and Schwann cells are more similar than previously thought.
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Encéfalo/fisiopatología , Neuroglía/fisiología , Plasticidad Neuronal , Fenilcetonurias/fisiopatología , Adulto , Animales , Biomarcadores , Encéfalo/patología , Proteína Ácida Fibrilar de la Glía/metabolismo , Gliosis/patología , Humanos , Ratones , Ratones Mutantes/genética , Mutación , Proteína Básica de Mielina/genética , Vaina de Mielina/metabolismo , Vaina de Mielina/ultraestructura , Oligodendroglía/metabolismo , Oligodendroglía/patología , Fenilalanina/sangre , Fenilalanina Hidroxilasa/genética , Fenilcetonurias/patología , ARN Mensajero/metabolismoRESUMEN
Animal models of human tumors serve a vital role in the development and testing of new anticancer therapies. Since the immune system is likely to play an essential role in tumor eradication, there is a particular need for modeling human disease in immunocompetent hosts. Few models of glioma have been developed in immunocompetent mice that are commercially available and none of these tumors have histological and antigenic characteristics of human gliomas. We have used a cell line, 4C8, derived from a spontaneous glioma-like tumor that arose in a transgenic mouse to develop a new glioma model. The intracranial injection of 4C8 cells into immunocompetent syngeneic B6D2F1 mice resulted in tumors that were densely cellular, developed a pseudopallisading pattern of necrosis, and expressed GFAP; all important features of human malignant gliomas. The average neurological endpoint was 51 days after intracranial injection. The 4C8 cells also grew rapidly in the flank, retaining histologic features seen in intracranial tumors. Flank tumors reached an average volume of 100 mm3, a volume ideal for therapy testing, by 34 days postinjection. These results suggest that the 4C8 mouse glioma model is an excellent system in which to test new antiglioma therapies for use in humans.