RESUMEN
BACKGROUND: Non-tuberculosis mycobacteria such as Mycobacterium chimaera are found widely in hospital water systems. Invasive M. chimaera infections have recently been attributed to heater-cooler units (HCUs) of cardiopulmonary bypass equipment. AIM: To assess the extent of microbiological contamination within the HCUs and to inform decontamination strategies for reducing the microbial load. METHODS: Water samples taken from HCUs used at University Hospitals Birmingham for cardiopulmonary bypass surgery were sampled to determine the number of micro-organisms by membrane filtration. Various decontamination processes were used throughout the study, all based on the manufacturer's guidance. FINDINGS: Total viable counts >300cfu per 100mL containing a wide variety of micro-organisms were obtained from water inside the HCUs. Working with the manufacturers, we significantly reduced the microbial load of the water within the HCUs by removing the internal tubing soiled with biofilm followed by a weekly decontamination regimen with peracetic acid. CONCLUSION: A decontamination cycle including an initial replacement of internal tubing with weekly microbiological water samples is required to maintain the water quality within HCUs at an acceptable level.
Asunto(s)
Descontaminación/métodos , Equipos y Suministros/microbiología , Control de Infecciones/métodos , Micobacterias no Tuberculosas/aislamiento & purificación , Carga Bacteriana , Puente Cardiopulmonar/efectos adversos , Filtración , Hospitales Universitarios , Humanos , Infecciones por Mycobacterium no Tuberculosas/prevención & control , Infección de la Herida Quirúrgica/prevención & control , Reino Unido , Microbiología del AguaRESUMEN
Genomic selection can increase genetic gain per generation through early selection. Genomic selection is expected to be particularly valuable for traits that are costly to phenotype and expressed late in the life cycle of long-lived species. Alternative approaches to genomic selection prediction models may perform differently for traits with distinct genetic properties. Here the performance of four different original methods of genomic selection that differ with respect to assumptions regarding distribution of marker effects, including (i) ridge regression-best linear unbiased prediction (RR-BLUP), (ii) Bayes A, (iii) Bayes Cπ, and (iv) Bayesian LASSO are presented. In addition, a modified RR-BLUP (RR-BLUP B) that utilizes a selected subset of markers was evaluated. The accuracy of these methods was compared across 17 traits with distinct heritabilities and genetic architectures, including growth, development, and disease-resistance properties, measured in a Pinus taeda (loblolly pine) training population of 951 individuals genotyped with 4853 SNPs. The predictive ability of the methods was evaluated using a 10-fold, cross-validation approach, and differed only marginally for most method/trait combinations. Interestingly, for fusiform rust disease-resistance traits, Bayes Cπ, Bayes A, and RR-BLUB B had higher predictive ability than RR-BLUP and Bayesian LASSO. Fusiform rust is controlled by few genes of large effect. A limitation of RR-BLUP is the assumption of equal contribution of all markers to the observed variation. However, RR-BLUP B performed equally well as the Bayesian approaches.The genotypic and phenotypic data used in this study are publically available for comparative analysis of genomic selection prediction models.
Asunto(s)
Genoma de Planta , Técnicas de Genotipaje/métodos , Pinus taeda/genética , Basidiomycota/patogenicidad , Teorema de Bayes , Resistencia a la Enfermedad , Marcadores Genéticos , Genotipo , Modelos Lineales , Fenotipo , Pinus taeda/crecimiento & desarrollo , Pinus taeda/inmunología , Pinus taeda/microbiología , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/microbiología , Raíces de Plantas/genética , Raíces de Plantas/crecimiento & desarrollo , Polimorfismo de Nucleótido Simple , Carácter Cuantitativo HeredableRESUMEN
Pinus palustris Mill. (longleaf pine, LL) and Pinus elliottii Engelm. var. elliottii (slash pine, SL) frequently co-occur in lower coastal plain flatwoods of the USA, with LL typically inhabiting slightly higher and better-drained microsites than SL. The hydraulic architecture and tracheid dimensions of roots, trunk and branches of mature LL and SL trees were compared to understand their role in species microsite occupation. Root xylem had higher sapwood-specific hydraulic conductivity (k(s)) and was less resistant to cavitation compared with branches and trunk sapwood. Root k(s) of LL was significantly higher than SL, whereas branch and trunk k(s) did not differ between species. No differences in vulnerability to cavitation were observed in any of the organs between species. Across all organs, there was a significant but weak trade-off between water conduction efficiency and safety. Tracheid hydraulic diameter (D(h)) was strongly correlated with k(s) across all organs, explaining >73% of the variation in k(s). In contrast, tracheid length (L(t)) explained only 2.4% of the variability. Nevertheless, for trunk xylem, k(s) was 39.5% higher at 20 m compared with 1.8 m; this increase in k(s) was uncorrelated with D(h) and cell-wall thickness but was strongly correlated with the difference in L(t). Tracheid allometry markedly changed between sapwood of roots, trunks and branches, possibly reflecting different mechanical constraints. Even though vulnerability to cavitation was not different for sapwood of roots, branches or the trunks of LL and SL, higher sapwood to leaf area ratio and higher maximum sapwood-specific hydraulic conductivity in roots of LL are functional traits that may provide LL with a competitive advantage on drier soil microsites.
Asunto(s)
Pinus/anatomía & histología , Pinus/fisiología , Agua/metabolismo , Pinus/clasificación , Raíces de Plantas/anatomía & histología , Raíces de Plantas/fisiología , Tallos de la Planta/anatomía & histología , Tallos de la Planta/fisiología , ÁrbolesRESUMEN
The availability of nitrogen represents a key constraint on carbon cycling in terrestrial ecosystems, and it is largely in this capacity that the role of N in the Earth's climate system has been considered. Despite this, few studies have included continuous variation in plant N status as a driver of broad-scale carbon cycle analyses. This is partly because of uncertainties in how leaf-level physiological relationships scale to whole ecosystems and because methods for regional to continental detection of plant N concentrations have yet to be developed. Here, we show that ecosystem CO(2) uptake capacity in temperate and boreal forests scales directly with whole-canopy N concentrations, mirroring a leaf-level trend that has been observed for woody plants worldwide. We further show that both CO(2) uptake capacity and canopy N concentration are strongly and positively correlated with shortwave surface albedo. These results suggest that N plays an additional, and overlooked, role in the climate system via its influence on vegetation reflectivity and shortwave surface energy exchange. We also demonstrate that much of the spatial variation in canopy N can be detected by using broad-band satellite sensors, offering a means through which these findings can be applied toward improved application of coupled carbon cycle-climate models.
Asunto(s)
Carbono/metabolismo , Clima , Ecosistema , Nitrógeno/metabolismo , Árboles/metabolismo , Monitoreo del Ambiente/métodos , Retroalimentación , Modelos Biológicos , Hojas de la Planta/metabolismo , Nave Espacial , TemperaturaRESUMEN
BACKGROUND: There has been a recent surge of interest in the role of growth differentiation factors and other bone morphogenic proteins in the development and spread of cancer. In this study we have provided evidence that highlights the significance of growth and differentiation factor-9a (GDF-9a) and GDF-9b (bone morphogenic protein-15, BMP-15) in breast cancer development and progression. METHODS: Primary breast cancer samples (n = 109) and matched background tissues from same patients (n = 33) were processed for frozen section and RNA extraction. Frozen sections from matched tissues were immunostained with GDF-9a and GDF-9b antibodies. Staining intensity was analyzed by computer image analysis. RNA was reverse transcribed and quantified before analysis by quantitative polymerase chain reaction (Q-PCR). Results were expressed as number of transcripts (standardized by beta-actin). The data were compared with the clinical outcome of the disease. The biological effects of the molecule were studied using in vitro assays after forced expression in breast cancer cells. RESULTS: Highly aggressive breast cancer cells did not express GDF-9a. On forced expression of GDF-9a, breast cancer cells became less invasive. These laboratory findings were analyzed against the clinical information. Primary breast cancer samples with good predicted prognosis had a significantly higher level of GDF-9a than in samples with poor predicted prognosis (P = .004). Patients who remained disease-free at the end of a 10-year follow-up had significantly higher levels of both GDF-9a and GDF-9b in their tissue than those with poor clinical outcome (P = .001 and .014, respectively). CONCLUSION: Growth differentiation factor-9 family expressed in breast cancer has an inhibitory effect on the progression of human breast cancer.
Asunto(s)
Neoplasias de la Mama/fisiopatología , Péptidos y Proteínas de Señalización Intercelular/biosíntesis , Proteína Morfogenética Ósea 15 , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Adhesión Celular/fisiología , Línea Celular Tumoral , Progresión de la Enfermedad , Femenino , Factor 9 de Diferenciación de Crecimiento , Humanos , Metástasis Linfática , PronósticoRESUMEN
The expression of certain CD44 variants has been linked with metastasis and tumour progression. In particular, high molecular weight forms of CD44 show restricted expression in tumours and may correlate with tumour development and metastasis. In this study, we examined the expression of CD44 variants in prostate cancer cell lines: the invasive PC-3 and DU-145, low invasive LNCaP, and two non-invasive prostate epithelial cell lines. PC-3 prostate cancer cells were transfected with a high molecular weight CD44 variant isoform, CD44v3-v10, isolated from non-invasive prostate epithelial cell lines. These transfected cells (PC-NIVO) were assessed using in vitro invasion, tumour-endothelial, growth, and migration assays. The expression of MMP-14 was examined using SDS-PAGE and Western blot analysis. Transfected PC-3 cells (PC-NIVO) were found to be less adherent to endothelial cells and had significantly reduced invasiveness compared to wild-type PC-3 or control cells. In addition, tumour cell adhesion to endothelial cells and invasiveness was increased after exposure to HGF/SF, and can be blocked by the presence of anti-CD44 antibodies. Further investigation revealed a reduction in the expression of MMP-14 in PC-NIVO cells, but not in PC-3 or control cells. In conclusion, non-invasive prostate epithelial cells express a high molecular weight CD44 isoform, CD44v3-v10, which may counteract the standard isoform function of CD44 by reducing adhesion and invasion of endothelium by prostate tumour cells through negation of the MMP-14 function.
Asunto(s)
Movimiento Celular , Receptores de Hialuranos/fisiología , Neoplasias de la Próstata/enzimología , Neoplasias de la Próstata/fisiopatología , Adhesión Celular/genética , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular , Clonación Molecular , Regulación Neoplásica de la Expresión Génica , Humanos , Receptores de Hialuranos/genética , Masculino , Metaloproteinasas de la Matriz/genética , Metaloproteinasas de la Matriz/metabolismo , Metaloproteinasas de la Matriz Asociadas a la Membrana , Invasividad Neoplásica , Neoplasias de la Próstata/patología , Transfección , Regulación hacia ArribaRESUMEN
The Coxsackie-adenovirus receptor (CAR) is the primary site for adenovirus attachment during infection and has been used as a delivery mechanism for gene therapies. However, the expression profile of the receptor in cancer, particularly in clinical breast cancer, is poorly reported. This study evaluated the expression of CAR in human breast cancers. Frozen sections from breast cancer primary tumours (matched tumour n=114 and background n=30) were immunostained with CAR antibody. RNA was reverse transcribed and analysed by quantitative-PCR (Q-PCR). Levels of CAR were analysed against the clinical background, with a median follow-up of 72 months. Staining intensity of CAR was increased within tumour sections compared to background tissue. Q-PCR revealed significantly elevated levels of CAR transcript in breast tumours (32 313+/-7067 mean+/-SE vs. background tissue 11 483+/-7069, P=0.023). CAR expression also increased with grade of tumour. Patients who had tumour metastases also showed elevated levels of CAR expression (metastasis: 61 940+/-22 749 vs. alive and well 29 655+/-8149), however those with local recurrences had reduced levels of CAR. Ductal carcinomas expressed lower levels of CAR compared to tumours of other types. Tumours with nodal involvement were also associated with higher levels of CAR (node positive 2320 median vs. node negative 1077.5). Levels of CAR were significantly correlated with long-term survival over a period of 6 years (P=0.004, univariate analysis). We conclude that CAR expression is elevated in primary breast cancers. This may have a bearing on its use as means of delivery for gene therapy and suggests that further work is necessary to understand this complex molecule.
Asunto(s)
Neoplasias de la Mama/metabolismo , Receptores Virales/biosíntesis , Adenoviridae , Mama/metabolismo , Neoplasias de la Mama/patología , Carcinoma Ductal de Mama/metabolismo , Carcinoma Ductal de Mama/patología , Línea Celular Tumoral , Proteína de la Membrana Similar al Receptor de Coxsackie y Adenovirus , Enterovirus , Femenino , Estudios de Seguimiento , Humanos , Metástasis de la Neoplasia , Estadificación de Neoplasias , Pronóstico , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Most people hold beliefs about personality characteristics typical of members of their own and others' cultures. These perceptions of national character may be generalizations from personal experience, stereotypes with a "kernel of truth," or inaccurate stereotypes. We obtained national character ratings of 3989 people from 49 cultures and compared them with the average personality scores of culture members assessed by observer ratings and self-reports. National character ratings were reliable but did not converge with assessed traits. Perceptions of national character thus appear to be unfounded stereotypes that may serve the function of maintaining a national identity.
Asunto(s)
Carácter , Cultura , Etnicidad , Personalidad , Adolescente , Adulto , Comparación Transcultural , Femenino , Humanos , Masculino , Determinación de la Personalidad , Reproducibilidad de los Resultados , Percepción Social , Estereotipo , Encuestas y CuestionariosRESUMEN
AIMS: Vascular endothelial (VE)-cadherin, also known as cadherin-5 and CD144, is an adhesion molecule uniquely expressed in endothelial cells. We hypothesized that VE-cadherin may be a useful marker for assessing microvessels and angiogenesis in human breast cancer and sought to determine whether a correlation exists between levels of VE-cadherin, angiogenic markers factor VIII and platelet endothelial cell adhesion molecule (PECAM)-1 and patient outcome in breast cancer. METHODS AND RESULTS: Frozen sections from breast cancer primary tumours (tumour n = 114, background n = 30) were immunostained with VE-cadherin, factor VIII and PECAM-1 antibodies and microvessel number was assessed. RNA was reverse transcribed and analysed by quantitative polymerase chain reaction (Q-PCR). VE-cadherin immunostaining showed a significant difference in microvessel number in tumour compared with background. There was no significant difference in the number of microvessels stained with PECAM-1 or factor VIII; there was increased staining of other structures within the sample and higher general background staining. Q-PCR revealed elevated levels of VE-cadherin and PECAM-1 in tumour samples compared with background tissue and in patients with a poor prognosis, as determined by the Nottingham Prognostic Index. There was no difference in levels with factor VIII. Both VE-cadherin and PECAM-1 had significantly reduced expression in lobular compared with ductal carcinomas: there was no difference with factor VIII. CONCLUSION: Higher levels of angiogenic marker molecules in breast cancer may have an association with poor prognosis in patients. Moreover, VE-cadherin appears to be a preferable marker for such analysis.
Asunto(s)
Vasos Sanguíneos/patología , Neoplasias de la Mama/irrigación sanguínea , Cadherinas/genética , Antígenos CD , Vasos Sanguíneos/metabolismo , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Cadherinas/análisis , Diferenciación Celular , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Inmunohistoquímica , Metástasis Linfática , Neovascularización Patológica , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/análisis , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/genética , Valor Predictivo de las Pruebas , Pronóstico , ARN Mensajero/genética , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Tromboplastina/análisis , Tromboplastina/genéticaRESUMEN
Objetivo. Nuestro objetivo ha sido el determinar el impacto de la presencia o ausencia de marcadores ecográficos menores en el segundo trimestre de gestación para el riesgo de aneuploidía en los distintos grupos de edad materna. Material y métodos. Se trata de un estudio retrospectivo en el cual se evalúan 642 amniocentesis realizadas con indicación de estudio del cariotipo fetal. Las pacientes son divididas en cuatro grupos de estudio en función de su edad y según presentaran o no marcadores ecográficos de aneuploidía. Resultados. Se encontró anomalía cromosómica en siete de 15 (46,7 por ciento) mujeres de edad avanzada con anomalías ecográficas menores y en cuatro de 436 (0,91 por ciento) mujeres de edad avanzada con ecografía normal. Del mismo modo se detectó anomalías cromosómicas en nueve de 55 (16,36 por ciento) mujeres menores de 35 años con presencia de anomalías ecográficas menores y en una de 114 (0,87 por ciento) mujeres menores de 35 años con ecografía normal. Conclusiones. La presencia de anomalías ecográficas menores aumenta considerablemente el riesgo de aneuploidía en ambos grupos de edad materna y su ausencia disminuye el riesgo. En ausencia de marcadores ecográficos de aneuploidía el riesgo de las mujeres mayores de 35 años es equiparable al de las menores de 35 años. De esta forma el resultado ecográfico puede ayudar a las mujeres en su decisión de someterse a una prueba invasiva de diagnóstico prenatal (AU)
Asunto(s)
Adulto , Embarazo , Femenino , Humanos , Aneuploidia , Ultrasonografía Prenatal , Factores de Riesgo , Sensibilidad y Especificidad , Estudios Retrospectivos , Factores de EdadRESUMEN
CD44 is a multifunctional cell surface adhesion molecule that has been implicated in tumour cell invasion and metastasis. Many cancer cell types as well as their metastases express high levels of CD44. Furthermore, the expression of certain CD44 variants has been linked with metastasis and tumour progression. It is known that ezrin, a member of the ERM family of proteins, can bind to CD44 and thus raises the possibility that it is involved in cell migration and metastasis. Therefore we examined the expression and distribution of CD44, its co-localisation and translocation with ezrin in prostate cancer cell lines as they interact with endothelial cells. Experimental results indicate prostate cancer cells express multiple CD44 isoforms that co-localise with ezrin in DU-145 and PC-3 prostate cancer cells. Treatment with hepatocyte growth factor (HGF/SF) resulted in up-regulation of CD44 and its co-translocation with ezrin during tumour-endothelial cell interactions. In addition, tumour cell adhesion to endothelial cells and their invasiveness was increased after exposure to HGF/SF, and can be blocked by the presence of anti-CD44 antibodies. It is concluded that CD44 and ezrin interact in endothelial cells and that they co-localise in the areas of tumour-endothelial contact. The CD44/ezrin complex plays a pivotal role in the capture and invasion of endothelial cells by prostate cancer cells.
Asunto(s)
Endotelio/patología , Receptores de Hialuranos/análisis , Fosfoproteínas/análisis , Neoplasias de la Próstata/patología , Proteínas del Citoesqueleto , Humanos , Receptores de Hialuranos/fisiología , Masculino , Invasividad Neoplásica , Fosfoproteínas/fisiología , Neoplasias de la Próstata/química , Isoformas de Proteínas , Células Tumorales CultivadasRESUMEN
BACKGROUND: Vascular endothelial cadherin (VE-cadherin/cadherin-5) has previously been described as playing a specific role in angiogenesis due to its localisation at areas of intercellular contact, where it functions in maintenance of tubular architecture. Matrix-bound fibroblasts have been show to produce a number of factors that are important in inducing angiogenesis and to promote tubule-formation by human endothelial cells, an indicator of angiogenic potential. RESULTS: Tubule formation stimulated by fibroblast-derived growth factors can be prevented by the addition of monoclonal antibody to VE-cadherin. In addition, fibroblasts-derived growth factors are able to modulate the expression and hence the regulation of this endothelial cell specific cadherin. CONCLUSIONS: The change in VE-cadherin expression of human endothelial cells by fibroblast-derived growth factors may contribute to the regulation of angiogenesis.
Asunto(s)
Cadherinas/metabolismo , Fibroblastos/metabolismo , Neovascularización Fisiológica , Transactivadores , Antígenos CD , Western Blotting , Adhesión Celular , Células Cultivadas , Técnicas de Cocultivo , Medios de Cultivo Condicionados , Medio de Cultivo Libre de Suero , Proteínas del Citoesqueleto/metabolismo , Endotelio Vascular/citología , Endotelio Vascular/metabolismo , Humanos , Inmunohistoquímica , Octoxinol , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , beta CateninaRESUMEN
Tight Junctions govern the permeability of endothelial and epithelial cells and are the most topical structures of these cell types. Tight junctions create an intercellular barrier and intramembrane diffusion fence. An important step in the formation of cancer metastases interaction and penetration of the vascular endothelium by dissociated cancer cells. Early studies demonstrated a correlation between the reduction of tight junctions and tumour differentiation and experimental evidence has emerged to place tight junctions in the frontline as the structure that cancer cells must overcome in order to metastasise. Changes in tight junction function are thus an early and key aspect in cancer metastasis. Further work is required to fully realise the potential that this structure has in cancer invasion and metastasis in order to develop new and novel therapies in the prevention of tumour metastasis.
Asunto(s)
Metástasis de la Neoplasia/patología , Uniones Estrechas/patología , Animales , Humanos , Metástasis de la Neoplasia/prevención & control , Neoplasias/patología , Neovascularización Patológica/patología , Uniones Estrechas/metabolismo , Uniones Estrechas/ultraestructuraRESUMEN
PURPOSE: Hepatocyte growth factor/scatter factor (HGF/SF), via its receptor c-MET, has been implicated to play a pivotal role in breast cancer development and progression. This study examined a transgene-consisting of a combination of U1snRNA, hammerhead ribozyme, and antisense, designed to inhibit c-met expression-and its impact on the migration and in vitro invasion of breast cancer cells. EXPERIMENTAL DESIGN: A hammerhead ribozyme targeting human c-MET was cloned into a modified pZeoU1EcoSpe vector and transfected into breast cancer cells MDA MB 231 and MCF-7 by electroporation. Expression of MET mRNA and protein was determined. Migration and in vitro invasiveness of transfected cells were also analyzed. RESULTS: Breast cancer cells were transfected with the ribozyme-containing plasmids. Stable transfectants manifested an almost complete loss of MET mRNA and protein, as shown by reverse transcription-PCR, Northern blotting, and Western blotting, respectively, whereas the wild-type plasmid had no effects. Met-ribozyme transfected cells exhibited reduced migration and in vitro invasiveness through extracellular matrix (Matrigel), compared with the wild-type cells and cells transfected with empty plasmid. CONCLUSIONS: These data show that targeting c-MET by way of a hammerhead ribozyme encoding antisense to c-MET is an effective approach in reducing the invasiveness of breast cancer cells.
Asunto(s)
Neoplasias de la Mama/patología , Proteínas Proto-Oncogénicas c-met/genética , ARN Catalítico/genética , Secuencia de Bases , Neoplasias de la Mama/genética , Neoplasias de la Mama/terapia , Movimiento Celular/genética , ADN sin Sentido/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Datos de Secuencia Molecular , Invasividad Neoplásica/genética , Invasividad Neoplásica/prevención & control , Plásmidos/genética , Proteínas Proto-Oncogénicas c-met/metabolismo , ARN Catalítico/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Nuclear Pequeño/genética , ARN Nuclear Pequeño/metabolismo , Factores de Tiempo , Transfección , Células Tumorales CultivadasRESUMEN
The present study demonstrated that the magnitude of after-effect due to wedge prisms depends on the form of the visual feedback used to represent hand and target position in fast, targeted, transverse reaches. Trained human subjects made reaches with and without prisms in three visuomotor representations (VR): (1) the subject's actual hand and targets (Direct), (2) a real-time video broadcast of hand and targets (Video), or (3) abstract, computer-generated targets and a cursor representing hand position (Cursor). A significant after-effect occurred in each VR. However, the magnitude of the after-effect was significantly different among VRs: the magnitude was greatest in Direct, smaller in Video and smallest in Cursor. A significant after-effect (carryover) also occurred when a subject prism-adapted reaches in one VR and then removed the prisms and made initial reaches in another VR. Our data showed that when reaches were prism-adapted in Direct and then prisms were removed, there was a large carryover to initial reaches in Video or Cursor (D-->V and D-->C). In contrast, when prisms were worn in Video and removed for reaches in Direct (V-->D), there was a significantly smaller carryover than from both D-->V and D-->C. Finally, when prisms were worn in Cursor and removed for reaches in Direct (C-->D), there was very little detectable carryover. Our results suggest that adaptation is context-dependent and that the magnitude of carryover is dependent on the VR in which adaptation occurred. Interpretations of adaptations made in abstract training and experimental conditions may be greatly affected by this finding.
Asunto(s)
Adaptación Fisiológica/fisiología , Retroalimentación/fisiología , Fuerza de la Mano/fisiología , Mano/fisiología , Movimiento/fisiología , Desempeño Psicomotor/fisiología , Percepción Espacial/fisiología , Adulto , Anteojos/efectos adversos , Femenino , Fijación Ocular/fisiología , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Orientación/fisiología , Distorsión de la Percepción/fisiología , Estimulación Luminosa/métodos , Propiocepción/fisiología , Grabación en VideoRESUMEN
In a previous study, others have hypothesized that the variance in vertical errors that occurs while throwing at visual targets is caused by changes in any of three throw parameters: hand location in space, hand translational velocity, and hand orientation. From an analysis of skilled throwers, those authors concluded that vertical error is best correlated with variance in hand orientation, which in turn is related to the timing of ball release. We used a vertical prism adaptation paradigm to investigate which of these throwing parameters subjects use when adapting to external perturbation. Our subjects showed no correlation between hand position or hand translational velocity and ball impact height in normal, over-practiced throwing. However, video-based motion analysis showed that modifications both of position and speed of the hand play an important role when subjects are forced to compensate for a vertically shifting prism perturbation during a dart-like throw (these factors contribute approximately 30% of the adaptation). We concluded that, during adaptation, more degrees of freedom and more sources of potential error are modified to achieve the gaze-throw recalibration required to hit the target than are employed in this type of throw during normal conditions.
Asunto(s)
Adaptación Fisiológica/fisiología , Distorsión de la Percepción/fisiología , Desempeño Psicomotor/fisiología , Conducta Espacial/fisiología , Adulto , Fenómenos Biomecánicos , Anteojos , Femenino , Mano/fisiología , Humanos , Masculino , Factores de Tiempo , Grabación de Cinta de Video , Muñeca/fisiologíaRESUMEN
Acute infectious lymphocytosis is characterized by marked peripheral blood lymphocytosis, often associated with a mild, nonspecific febrile illness. We present a 4-year-old girl with acute infectious lymphocytosis associated with Giardia lamblia and Blastocystis hominis coinfection. Analysis of peripheral lymphocyte markers showed overall proliferation of B and T cells with a reduction in the proportion of T cells, especially in the CD4T cell subpopulation. Hematologic values returned to normal after treatment with metronidazole.
Asunto(s)
Infecciones por Blastocystis/diagnóstico , Giardiasis/diagnóstico , Linfocitosis/parasitología , Enfermedad Aguda , Animales , Antiinfecciosos/uso terapéutico , Infecciones por Blastocystis/tratamiento farmacológico , Blastocystis hominis , Preescolar , Femenino , Giardia lamblia , Giardiasis/tratamiento farmacológico , Humanos , Linfocitosis/diagnóstico , Metronidazol/uso terapéuticoRESUMEN
Hepatocyte growth factor (HGF)/scatter factor (SF) is a cytokine exerting a wide range of biological functions on many cell types, including vascular endothelial cells. HGF/SF increases migration, motility, and dissociation of human umbilical vascular endothelial cells (HUVECs). This study demonstrated that such action of HGF/SF on HUVECs was achieved by regulation of the endothelial cell-specific cadherin, vascular endothelial (VE)-cadherin. HGF/SF induced a time-dependent reduction of VE-cadherin protein from HUVECs as shown by Western blotting and immunocytochemistry, accompanied by an increase in the migration of HUVECs. The change of VE-cadherin appeared at the mRNA level, as demonstrated by reverse transcription-PCR, with a decrease in the VE-cadherin signal. These results show, for the first time, that HGF/SF targets the endothelial cell-specific adhesion molecule VE-cadherin.
Asunto(s)
Cadherinas/biosíntesis , Endotelio Vascular/citología , Endotelio Vascular/metabolismo , Factor de Crecimiento de Hepatocito/metabolismo , Animales , Antígenos CD , Western Blotting , Adhesión Celular , Movimiento Celular , Células Cultivadas , Técnicas de Cocultivo , Electroforesis en Gel de Poliacrilamida , Humanos , Inmunohistoquímica , Ratones , Neovascularización Patológica , ARN/metabolismo , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Tiempo , Venas Umbilicales/citologíaRESUMEN
The use of Di-I in tract-tracing is briefly reviewed and a novel delayed-fixation approach to neural tract-tracing in the postmortem human adult brain is reported. Using the new approach, fast Di-I, a highly lipophilic fluorescent dye was injected into a particular region or nucleus and labelled tracts were followed for distances of some 20-40 mm. The procedure required approximately 36 h, yielding dye penetration rates of 1.0 mm/h or more. This contrasts with previous Di-I, silver impregnation, and horseradish peroxidase protocols, where the tracer penetration rate is typically 0.003 mm/h or less, and the distance traversed amounts to only a few mm even after months of incubation. The new method hinges on the simple consideration that aldehyde fixation, which is normally employed prior to administration of the marker, crosslinks membrane proteins and impedes dye diffusion. The short postmortem samples used in our protocol permit delaying fixation until after the dye has had time to penetrate, dramatically increasing the length and scope of neural circuits that can be traced. Using these methods, for example, we have confirmed the presence of an ipsilateral olivocerebellar climbing fiber projection in the human.
Asunto(s)
Axones/ultraestructura , Encéfalo/citología , Carbocianinas , Colorantes Fluorescentes , Red Nerviosa/citología , Vías Nerviosas/citología , Animales , Axones/fisiología , Encéfalo/fisiología , Difusión/efectos de los fármacos , Humanos , Inyecciones/métodos , Red Nerviosa/fisiología , Vías Nerviosas/fisiología , Fijación del Tejido/métodos , Fijación del Tejido/normasRESUMEN
Increased prevalence of Alzheimer's disease-like beta-amyloid deposits in the neuropil and within neurons occurs in the brains of non-demented individuals with heart disease. Heart disease is a prevalent finding in Alzheimer's disease, and may be a forerunner to the dementing disorder. In the cholesterol-fed rabbit model of human coronary heart disease there is production and accumulation of beta-amyloid in the brain. This accumulation of beta-amyloid can be reversed by removing cholesterol from the rabbits' diet. In culture cells, a cholesterol challenge has been shown to increase production of beta-amyloid, and dramatic reductions of cholesterol produced by HMG Co-A reductase inhibitors decrease production of beta-amyloid. Increased beta-amyloid production is also produced by dietary cholesterol in a number of transgenic mouse models of Alzheimer's disease. Administration of HMG Co-A reductase inhibitors may block beta-amyloid production caused by dietary cholesterol in rabbits. Clinical trials testing the benefit of HMG Co-A reductase inhibitors in the treatment of Alzheimer's disease are underway.