RESUMEN
PURPOSE: Contact lens wear carries a risk of complications, including corneal infection. Solving these complications has been hindered by limitations of existing animal models. Here, we report development of a new murine model of contact lens wear. METHODS: C57BL/6 mice were fitted with custom-made silicone-hydrogel contact lenses with or without prior inoculation with Pseudomonas aeruginosa (PAO1-GFP). Contralateral eyes served as controls. Corneas were monitored for pathology, and examined ex vivo using high-magnification, time-lapse imaging. Fluorescent reporter mice allowed visualization of host cell membranes and immune cells. Lens-colonizing bacteria were detected by viable counts and FISH. Direct-colony PCR was used for bacterial identification. RESULTS: Without deliberate inoculation, lens-wearing corneas remained free of visible pathology, and retained a clarity similar to non-lens wearing controls. CD11c-YFP reporter mice revealed altered numbers, and distribution, of CD11c-positive cells in lens-wearing corneas after 24â¯h. Worn lenses showed bacterial colonization, primarily by known conjunctival or skin commensals. Corneal epithelial cells showed vacuolization during lens wear, and after 5 days, cells with phagocyte morphology appeared in the stroma that actively migrated over resident keratocytes that showed altered morphology. Immunofluorescence confirmed stromal Ly6G-positive cells after 5 days of lens wear, but not in MyD88 or IL-1R gene-knockout mice. P. aeruginosa-contaminated lenses caused infectious pathology in most mice from 1 to 13 days. CONCLUSIONS: This murine model of contact lens wear appears to faithfully mimic events occurring during human lens wear, and could be valuable for experiments, not possible in humans, that help solve the pathogenesis of lens-related complications.
Asunto(s)
Lentes de Contacto , Córnea/microbiología , Infecciones Bacterianas del Ojo/microbiología , Queratitis/microbiología , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/aislamiento & purificación , Receptores Tipo I de Interleucina-1/genética , Animales , Recuento de Colonia Microbiana , Lentes de Contacto/efectos adversos , Córnea/patología , Modelos Animales de Enfermedad , Infecciones Bacterianas del Ojo/metabolismo , Infecciones Bacterianas del Ojo/patología , Queratitis/metabolismo , Queratitis/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Microscopía Confocal , Infecciones por Pseudomonas/metabolismo , Infecciones por Pseudomonas/patología , Receptores Tipo I de Interleucina-1/metabolismo , Tomografía de Coherencia ÓpticaRESUMEN
OBJECTIVES: To assess contact lens preservative uptake and release from multipurpose solutions (MPS) and subsequent acquisition of lens antibacterial activity. METHODS: Kinetics of uptake and release of poly (hexamethylene biguanide hydrochloride) (PHMB) or polyquaternium-1 (PQ-1) from various contact lenses were studied initially with the pure compounds and then after soaking in MPS containing these compounds. Lenses soaked in MPS were tested for antibacterial activity. RESULTS: Only lenses with a negatively charged component absorbed these preservatives. For lenses containing methacrylic acid (MA), uptake of PHMB from preservative-only solution was fast, yet little was released, in contrast to its rapid release from lenses containing other anionic groups. This trend persisted with PHMB-containing MPS. PQ-1 from preservative-only solution was only absorbed by lenses containing MA and was released from MA-containing hydrogels, but not significantly from an MA-containing silicone hydrogel. Lens uptake of PQ-1 was much lower from MPS and release was essentially undetectable from all lenses evaluated. Antibacterial lens activity was acquired by lenses containing MA after an overnight soak in MPS containing PQ-1, and for balafilcon A and omafilcon A after 5 exchanges in PHMB-containing MPS. Acquired activity was maintained during cycling between artificial tear protein solution and MPS. CONCLUSIONS: Lens preservative uptake and its subsequent release are dependent on lens chemistry, preservative nature, and other MPS components. A few lens/solution combinations acquired antibacterial activity after one or more overnight soaks in MPS, depending on the nature of the anionic lens component and the preservative. Uncharged lenses did not acquire antibacterial activity.
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Antiinfecciosos/química , Bacterias/efectos de los fármacos , Soluciones para Lentes de Contacto/química , Lentes de Contacto Hidrofílicos , Conservadores Farmacéuticos/química , Antiinfecciosos/farmacología , Biguanidas/química , Biguanidas/farmacología , Soluciones para Lentes de Contacto/farmacología , Humanos , Conservadores Farmacéuticos/farmacologíaRESUMEN
Secondary control (acceptance of and adjustment to negative events) is thought to promote positive affect. We examined the opposite path: could positive affect increase secondary control, particularly among individuals high in causal uncertainty, who stand to benefit from it the most? In two studies, participants completed a causal uncertainty scale, thought about a problem while listening to affect-inducing music or no music, and then completed items that assessed secondary control. In Study 1, the music induced positive or negative affect. In Study 2, the music induced affect that was high or low in activation and positive or negative in valence. In both studies, we found that positive affect-inducing music increased secondary control among high causal uncertainty participants. Furthermore, trait affect did not account for the effects of causal uncertainty, and music did not influence primary control. These findings show that secondary control can fluctuate as a function of state affect.
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Adaptación Psicológica , Afecto , Incertidumbre , Femenino , Humanos , Masculino , Música/psicología , Adulto JovenRESUMEN
In adults and older children, evidence consistent with relative separation between selective and sustained attention, superimposed upon generally positive inter-test correlations, has been reported. Here we examine whether this pattern is detectable in 5-year-old children from the healthy population. A new test battery (TEA-Ch(J)) was adapted from measures previously used with adults and older children and administered to 172 5-year-olds. Test-retest reliability was assessed in 60 children. Ninety-eight percent of the children managed to complete all measures. Discrimination of visual and auditory stimuli were good. In a factor analysis, the two TEA-Ch(J) selective attention tasks (one visual, one auditory) loaded onto a common factor and diverged from the two sustained attention tasks (one auditory, one motor), which shared a common loading on the second factor. This pattern, which suggests that the tests are indeed sensitive to underlying attentional capacities, was supported by the relationships between the TEA-Ch(J) factors and Test of Everyday Attention for Children subtests in the older children in the sample. It is possible to gain convincing performance-based estimates of attention at the age of 5 with the results reflecting a similar factor structure to that obtained in older children and adults. The results are discussed in light of contemporary models of attention function. Given the potential advantages of early intervention for attention difficulties, the findings are of clinical as well as theoretical interest.
Asunto(s)
Atención/fisiología , Pruebas Neuropsicológicas , Adulto , Preescolar , Femenino , Humanos , Pruebas de Inteligencia , Masculino , Reproducibilidad de los ResultadosRESUMEN
Unilateral spatial neglect, a debilitating condition affecting awareness of one side of space, is commonly assessed using cancellation tasks in which patients cross out targets distributed over a sheet. Standard scores emphasize the left-right distribution of omissions. Here, the additional value of extracting temporal as well as spatial aspects of performance from video recordings was examined. Videos from 18 patients with left neglect and 19 healthy age-matched control participants were obtained. Interrater reliability of the video analysis was high. In addition to overall differences in target detection and bias, patients significantly differed from the control group in terms of the location of first cancellation, overall slowness, greater variability in speed, systematic slowing with time on task and as a function of target location, less coherent search organization, and a sharply increased tendency to recancel targets. Considering a subset of patients whose scores, by standard criteria, were at or near the normal range indicated that these additional variables indeed increased the sensitivity of the task as well as allowed the simultaneous assessment of spatial and nonspatial aspects of the disorder.
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Lateralidad Funcional/fisiología , Trastornos de la Percepción/diagnóstico , Trastornos de la Percepción/fisiopatología , Desempeño Psicomotor/fisiología , Percepción Espacial/fisiología , Grabación en Video/métodos , Anciano , Anciano de 80 o más Años , Análisis de Varianza , Humanos , Persona de Mediana Edad , Pruebas Neuropsicológicas , Estimulación Luminosa/métodos , Tiempo de Reacción/fisiología , Valores de Referencia , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Factores de TiempoRESUMEN
Unilateral neglect, a lack of awareness for one side of space, is a common and debilitating consequence of stroke. Previous work has identified a relationship between enduring left neglect and diminished general alertness and shown that increasing alertness can temporarily reduce the severity of the spatial bias. In that research, alertness was modulated by loud tones or with pharmacological stimulants. Here we examine whether cognitive, endogenously driven changes can produce similar short-term improvements. Time-pressure is associated with increased subjective arousal and increased activation in cortical regions associated with alertness. Here five patients completed a spatial cancellation task with and without instructions regarding a time limit. Significant reductions in neglect severity were observed when patients believed that they were acting under time-pressure, despite the conditions being equivalent in the actual (unlimited) time available. Functional imaging work has highlighted the secondary effects that damage to networks mediating alertness can have on structurally intact spatial systems. The results here suggest that activation of presumably spared function in these damaged networks can induce moment-by-moment changes in spatial function and, crucially, that this can be achieved using entirely endogenous means.
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Sesgo , Lateralidad Funcional/fisiología , Trastornos de la Percepción/fisiopatología , Percepción Espacial/fisiología , Anciano , Anciano de 80 o más Años , Cognición/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Presión , Índice de Severidad de la Enfermedad , Factores de TiempoRESUMEN
Contact lenses are a safe and effective mode of vision correction used by more than 100 million people worldwide, yet some adverse responses to microbial contamination of contact lenses still occur. Various medical devices, including contact lens cases, currently use antimicrobial agents to eliminate or reduce microbial contamination at the surface. The application of antimicrobial surface technologies to contact lenses and lens cases is being explored. This article describes agents that hold promise for antimicrobial surfaces for contact lenses or lens cases.
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Antiinfecciosos/administración & dosificación , Lentes de Contacto/efectos adversos , Lentes de Contacto/microbiología , Antiinfecciosos/farmacología , Biopelículas/efectos de los fármacos , Contaminación de Equipos/prevención & control , Radicales Libres/metabolismo , Humanos , Percepción de QuorumRESUMEN
PURPOSE: Acanthamoeba castellani, ATCC 30234, cysts, and trophozoites after a 6-hour exposure. METHODS: Trophozoite cultures were prepared at Bio-Concept Laboratories in vented tissue culture flasks containing peptone yeast glucose broth by incubation (35 degrees C +/- 1 degrees C for 11 days). Cyst suspensions were prepared by incubation of trophozoites in phosphate-buffered saline plus heat-killed yeast on Page's saline agar plates (35 degrees C +/- 1 degrees C for 14 days). The solutions were inoculated in triplicate in respective lens cases. After the 6-hour exposure, aliquots of challenged solutions were transferred to Dey-Engley neutralizing broth and further diluted in peptone yeast glucose broth in tissue culture plates to the -7 dilution. Flasks and plates were incubated for 14 days at 35 degrees C +/- 1 degrees C and were examined with an inverted light microscope at day 14 for the presence of viable trophozoites. The most probable number method was used for approximate enumeration of the number of survivors. RESULTS: Mean log reductions for cysts were 1.8 for Clear Care/AOSEPT Plus, 2.0 for BLUE Vision/BLUE SEPT, 0.7 for Oxysept 1 Step, 0.5 for OPTI-FREE Express with Aldox, and 0.2 for easyvision one step+. Mean log reductions for trophozoites were 2.2 for Clear Care/AOSEPT Plus, 2.7 for BLUE Vision/BLUE SEPT, 2.5 for Oxysept 1 Step, 2.5 for OPTI-FREE Express with Aldox, and 1.8 for easyvision one step+. CONCLUSIONS: Only Clear Care/AOSEPT Plus and BLUE Vision/BLUE SEPT showed high levels of antimicrobial activity against the cyst form of A. castellani. Oxysept 1 Step showed mild activity against the cysts and easyvision one step+ and OPTI-FREE Express with Aldox showed virtually no antiacanthamoeba activity against the cyst form after 6 hours of exposure.
Asunto(s)
Acanthamoeba castellanii/efectos de los fármacos , Amebicidas/farmacología , Amebicidas/normas , Soluciones para Lentes de Contacto/farmacología , Soluciones para Lentes de Contacto/normas , Evaluación de Medicamentos , Acanthamoeba castellanii/crecimiento & desarrollo , Animales , Soluciones para Lentes de Contacto/química , Humanos , Factores de Tiempo , Trofozoítos/efectos de los fármacosRESUMEN
PURPOSE: Lens case contamination is a well-documented occurrence for contact lens wearers despite the efficacy of current lens disinfectants. Several microorganisms have a propensity to attach to surfaces and may become more tolerant of disinfection upon attachment. Non-compliance with disinfection regimens occasionally occurs wherein patients store their lenses in saline or in tap water. A silver-impregnated lens case was developed in an attempt to decrease case contamination. These studies examine the performance of the case both in vitro and in vivo. METHODS: In vitro, lens cases were challenged with 10(3) microorganism suspensions of bacteria. After 24h incubation at room temperature, aliquots of inocula were removed and spread plated onto appropriate growth media. Surviving colonies were counted and microorganism log drop values from initial challenge inocula were determined. Two 40-subject 1-month contralateral clinical studies were conducted with SOLO-care Aqua solution using one bowl of a silver-impregnated case and one bowl of a standard lens case for lens storage. Lens cases were collected and cultured for aerobic bacteria. RESULTS: In vitro efficacy data show significantly lower numbers of recovered microbes from silver-impregnated cases than from control cases. In both clinical studies, silver-impregnated cases had a statistically significantly lower proportion of bacterial contamination than control cases. The majority of microorganisms isolated from silver-impregnated cases were members of the normal skin flora. CONCLUSION: The performance of the silver-impregnated case in vitro and the observed lower proportion of contaminated silver-impregnated lens cases in a clinical setting demonstrate the case's ability to decrease bacterial contamination.
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Lentes de Contacto/microbiología , Desinfección/instrumentación , Contaminación de Equipos/prevención & control , Infecciones Bacterianas del Ojo/prevención & control , Plata , Recuento de Colonia Microbiana , Diseño de Equipo , Infecciones Bacterianas del Ojo/etiología , Estudios de Seguimiento , Humanos , Pronóstico , Estudios ProspectivosRESUMEN
Although transient neglect of contralesional space occurs following damage to either hemisphere, persistent forms are overwhelmingly associated with right hemisphere lesions. This has led to the suggestion that impairments in other right hemisphere systems--in particular those that mediate alertness--may undermine recovery. Reductions in neglect severity with stimulation, exacerbation with sedatives and the poor performance of chronic neglect patients on sustained attention tasks are consistent with this view. However, the question of whether changes in alertness exert a specific influence over spatial attention--or simply improve performance across many domains--is difficult to address using only patient studies. Here, we examine this question with individuals from the healthy adult population. On certain spatial tasks, adults show a modest but reliable leftward attentional bias. On the basis of the neglect studies, we hypothesised that this bias would diminish--or even reverse--as alertness levels declined. In the first study, participants were asked to judge the relative lengths of the left and right sections of a line when sleep deprived and when well rested. A significant rightward shift in attention was associated with sleep deprivation. A rightward shift was also observed over the course of the session. The second study replicated this time-on-task effect. The results suggest that a diminution in alertness may be sufficient to induce a rightward shift in visual attention in the healthy brain. Implications for the persistence of neglect in patients, for spatial biases in children and for normal free viewing asymmetries are discussed.
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Atención/fisiología , Lateralidad Funcional/fisiología , Juicio/fisiología , Privación de Sueño/fisiopatología , Percepción Espacial/fisiología , Adulto , Análisis de Varianza , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estimulación Luminosa/métodos , Desempeño Psicomotor/fisiología , Factores de TiempoRESUMEN
PURPOSE: Extracellular proteinase production and biofilm structure of Pseudomonas aeruginosa are affected by acylated homoserine lactones (AHLs) termed quorum sensing (QS) factors. C12- and C4-AHLs of P. aeruginosa and a synthetic furanone signaling antagonist were evaluated for effects on growth, primary adhesion to hydrogel contact lenses, and elastase B production of P. aeruginosa strains, including QS mutants, and isolates of Staphylococcus aureus and Staphylococcus epidermidis. METHODS: Acylated homoserine lactones and furanone were added to cultures of bacteria at various growth stages. Primary adhesion of P. aeruginosa to lenses soaked in AHLs and furanone was examined by adenosine triphosphate analysis. Elastase B activity of cultures exposed to AHLs and furanone was determined by an elastin congo red assay. RESULTS: Acylated homoserine lactones had no significant effects on maximal cell densities or primary adhesion. Adhesion of a lasI-rhlI- QS mutant to lenses was significantly lower than its wild-type (WT) strain, regardless of added AHL or furanone. Exogenous AHLs had negligible effects on elastase production of WT P. aeruginosa but restored elastase production in QS-deficient mutants. The furanone was biocidal for staphylococci but enhanced growth of the lasI-rhlI- QS mutant. The furanone decreased elastase production of WT strains but increased QS mutant elastase production. CONCLUSIONS: Exogenous AHLs and the furanone were of minor importance in initial adhesion of P. aeruginosa to lenses. The furanone decreased staphylococci growth and elastase production of WT P. aeruginosa but increased growth and elastase production of QS mutants. The data further indicate strain diversity in P. aeruginosa and complexity of AHL systems.
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4-Butirolactona/análogos & derivados , 4-Butirolactona/fisiología , Adhesión Bacteriana , Proteínas Bacterianas/biosíntesis , Proteínas Bacterianas/fisiología , Lentes de Contacto Hidrofílicos/microbiología , Metaloendopeptidasas/biosíntesis , Pseudomonas aeruginosa/crecimiento & desarrollo , Pseudomonas aeruginosa/enzimología , Staphylococcus aureus/enzimología , Staphylococcus aureus/crecimiento & desarrollo , Staphylococcus epidermidis/enzimología , Staphylococcus epidermidis/crecimiento & desarrolloRESUMEN
Studies examining a relationship between attention deficit hyperactivity disorder (ADHD) and relative visual inattention towards left space have produced inconsistent results. Here, based on previous studies with adult neurological patients who show very severe inattention to the left, we examine whether any spatial bias in ADHD may be modulated by changes in alertness levels. In a single case, we found that inattention to the left--that was intermittently apparent--dramatically increased as a function of time-on-task. No significant changes were observed on the right. The implications for clinical assessment and research design are discussed.
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Nivel de Alerta , Trastorno por Déficit de Atención con Hiperactividad/complicaciones , Atención , Trastornos de la Percepción/complicaciones , Percepción Espacial , Trastorno por Déficit de Atención con Hiperactividad/psicología , Niño , Humanos , Masculino , Trastornos de la Percepción/diagnóstico , Trastornos de la Percepción/psicología , Factores de Tiempo , Campos VisualesRESUMEN
PURPOSE: Bacterial strains with known capability to bind to hydrogel lenses were examined for their relative capacities to attach irreversibly to a hydrogel contact lens in pure and mixed cultures. METHODS AND RESULTS: Time course studies of adhesion through adenosine triphosphate (ATP) or radiolabel analyses indicated that primary adhesion by Pseudomonas aeruginosa to a 37% water-content hydrogel lens was more dense and rapid than that of Staphylococcus epidermidis. Primary adhesion of P. aeruginosa was similar after 5 min and 2 hr, whereas S. epidermidis showed an incremental increase in adhesion over the first 30 min. Sequential challenge of lenses with P. aeruginosa followed by S. epidermidis gave levels of primary adhesion for each species similar to those obtained with single pure cultures. When lenses were challenged with S. epidermidis first, primary adhesion of P. aeruginosa was significantly diminished. Exposures of multiple sets of lenses (n = 4) to a standard inoculum of P. aeruginosa resulted in levels of primary adhesion per lens after 1 hr equivalent to that found for a single lens in 5 min or in 2 hr. CONCLUSION: These data further support that normal biota may be protective for the eye. The data also suggest that under conditions of the primary adhesion-screening test, a limited number of cells of GSU no. 3 (selected phenotype) are involved in adhesion to the hydrogel.