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Objective:To explore the value of intermittent photic stimulation (IPS) in children′s video electroencephalography (EEG).Methods:The data of 8 994 children aged 1 to 18 years, who received IPS in the video EEG examination at the Liangjiang Campus of the Children′s Hospital of Chongqing Medical University from March 2021 to March 2022, were analyzed retrospectively.Patients were divided into non-epilepsy group and confirmed or suspected epilepsy group.Their IPS responses, clinical and EEG characteristics were collected.Categorical variables were expressed using frequencies and percentages.The relationship between IPS response and age was determined by Chi- square test or Fisher′ s exact probability method. Results:The median age of 8 994 children was 6.3 years.There were 2 310 (25.7%) children in the non-epileptic group, including 1 364 (59.0%) males and 946 (41.0%) females.There were 6 684 (74.3%) children in the confirmed or suspected epileptic group, including 3 842 (57.5%) males and 2 842 (42.5%) females.In the non-epileptic group, 141 cases (6.1%) had IPS photo-driving responses, and 1 case had photo paroxysmal response (PPR). In the confirmed or suspected epilepsy group, IPS photo-driving responses (2.4%) occurred in 160 cases, PPR (1.2%) in 82 cases, photo convulsion responses(0.3%) in 18 cases, and asymmetric photo-driving responses (0.2%) in 14 cases.The IPS photosensitivity responses varied among children of different ages, sexes, epileptic discharge types and seizure types in the confirmed or suspected epilepsy group.The children aged 6 to 18 years showed significantly stronger photosensitivity responses than those aged 1 to <6 years ( P<0.001). The photosensitivity activity in females was 1.9 times higher than that in males.The photosensitivity activity in patients with generalized discharges was 1.7 times more intense than that in patients with focal discharges.The photosensitivity reaction in patients with photo convulsive generalized seizures was 2.5 times stronger than that in patients with focal seizures. Conclusions:Routine standardized IPS is important for the detection of photosensitivity in children diagnosed or suspected with epilepsy.It can effectively guide the medical practice.
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Objective To research the characteristics of photosensitivity and EEG under different eye conditions of intermittent photic stimulation (IPS) in epilepsy children. Methods Epilepsy children showed positive under IPS were chose. The characteristics of photosensitivity and EEG under different eye conditions were analyzed. Results From 104 patients, background was normal in 101 cases (97. 1% ), background was slower in 3 cases (2. 8% ). Epileptic discharges during interictal periods was in 99 cases (95. 1% ), and generalized discharge was in 66 cases (63. 5% ), partial discharge was in 20 cases (19. 2% ), generalized discharge and partial discharge was in 13 cases (12. 5% ). Generalized discharge during IPS was in 96 cases (92. 3% ), partial discharge during IPS was in 8 cases (7. 7% ). The clinical attacking rate of IPS was significantly higher for those who showed positive in IPS in eye closure, opened, and closed condition than other patients (χ2 =4. 575,P=0. 032). Photosensitivity could increases then decreases as frequency increases, and reached highest when frequency was from 8 to 25 Hz. All of patients who generalized discharges during interval periods appeared generalized discharges during IPS, and 65. 0% patients who partial discharge during interval periods appeared generalized discharges during IPS; there was significant statistical differences (χ2 =20. 684, P<0. 001). Conclusions Photosensitivity is more common in idiopathic generalized epileptic children. The positive rate of IPS is higher under eye open or closure than eye closed, and it reaches highest when frequency is from 8 to 25 Hz. When photosensitivity happened under all three eye conditions, it is easily caused to seizure. The characteristic of discharge under IPS is strongly related to EEG of interictal periods and types of epilepsies.
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Fundamento: la calidad de un registro nistagmográfico durante los estudios del sistema vestibular, depende de la adecuada selección y colocación de los electrodos, los cuáles suelen ser ubicados en puntos específicos de la órbita ocular para permitir la recolección de la variación de potencial eléctrico generado entre la córnea y la retina causada por las sacudidas del nistagmo inducido o natural. Objetivo: presentar los resultados experimentales que demuestran esta influencia al cuantificar el efecto sobre los registros. Desarrollo: se empleó la técnica de estimulación visual con blanco móvil a diferentes frecuencias de movimiento, y los registros se realizaron en las condiciones de iluminación establecidas para electrooculografía, se utilizó un amplificador biomédico (electronistagmógrafo) de dos canales con frecuencia de muestreo de 1 kHz. Los Resultados obtenidos reflejan el cambio de las tensiones en los registros de acuerdo a la zona de colocación de los electrodos, al existir una zona óptima para el adecuado registro electronistagmográfico. Conclusiones: se demostró la afectación por zonas en los registros en el dominio temporal y de la frecuencia, y su influencia en la generación de errores en el diagnóstico topográfico de enfermedades que afectan el Sistema Vestibular.
Background: quality of record of electronystagmography during the studies of the vestibular system depends on the proper selection and placement of the electrodes, which are usually located at specific points in the eye socket to allow the collection of the variation of electric potential generated between the cornea and the retina caused by the jerking of the induced or natural nystagmus. Objective: to present the experimental results that demonstrate this influence by quantifying the effect on the records. Development: it was used the technique of visual stimulation with moving target at different frequencies of movement, and the records were made under the lighting conditions established in the published standard for electrooculography, using a two-channel amplifier with a sampling frequency of 1 kHz. The results obtained reflect the change in the tensions in the records according to the electrode placement zone, there being an optimal zone for the adequate record of electronystagmography. Conclusions: the affectation by zones in the records in the temporal domain and the frequency was demonstrated, and its influence in the generation of errors in the topographic diagnosis of diseases that affect the Vestibular System.
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Objective To observe the effect of exosomes secreted by retinal pigment epithelial (RPE) cells which damaged by blue light to Nod-like receptor protein (NLRP3). Methods Cultured ARPE-19 cells were divided into 2 groups; one group of RPE cells were exposed to blue light irradiation for 6 hours, the other group was cultured in routine environment. Total exosomes were extracted from the two groups by differential ultracentrifugation in low-temperature, and examined by transmission electron microscope to identify their forms. The exosomes were then incubated with normal ARPE-19 cells. The expression level of CD63, interleukin (IL)-1β, IL-18 and caspase-1 on the exosome surface were measured by Western blotting. The expressions of NLRP3 mRNA in RPE cells were detected by real-time fluorescence quantitative reverse transcription polymerase chain reaction (RT-PCR). Results Blue light damaged the cellular morphology. Transmission electron microscopy showed that the exosomes were 50-200nm in diameter and like double-concave disks. Blue light damaged cell-derived exosomes had significantly higher expression of IL-1β (t=18.04),IL-18 (t=12.55) and caspase-1 (t=14.70) than the control group (P<0.001). ARPE-19 cells cultured with blue light damaged cell-derived exosomes also had significantly higher expression of IL-1β (t=18.59), IL-18 (t=23.95) and caspase-1 (t=35.27) than control exosomes (P<0.001). RT-PCR showed that the relative expression of NLRP3 mRNA of PRE cells in experimental group and control group were 1.000±0.069 and 0.2±0.01, respectively, the difference was significant (t=12.20, P<0.001). Conclusion The expression IL-1β, IL-18 and caspase-1 and NLRP3 mRNA were upregulated by exosomes secreted by blue light damaged-RPE cells.
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Objective To observe the effect of exosomes secreted by retinal pigment epithelial (RPE) cells which damaged by blue light to Nod-like receptor protein (NLRP3). Methods Cultured ARPE-19 cells were divided into 2 groups; one group of RPE cells were exposed to blue light irradiation for 6 hours, the other group was cultured in routine environment. Total exosomes were extracted from the two groups by differential ultracentrifugation in low-temperature, and examined by transmission electron microscope to identify their forms. The exosomes were then incubated with normal ARPE-19 cells. The expression level of CD63, interleukin (IL)-1β, IL-18 and caspase-1 on the exosome surface were measured by Western blotting. The expressions of NLRP3 mRNA in RPE cells were detected by real-time fluorescence quantitative reverse transcription polymerase chain reaction (RT-PCR). Results Blue light damaged the cellular morphology. Transmission electron microscopy showed that the exosomes were 50-200nm in diameter and like double-concave disks. Blue light damaged cell-derived exosomes had significantly higher expression of IL-1β (t=18.04),IL-18 (t=12.55) and caspase-1 (t=14.70) than the control group (P<0.001). ARPE-19 cells cultured with blue light damaged cell-derived exosomes also had significantly higher expression of IL-1β (t=18.59), IL-18 (t=23.95) and caspase-1 (t=35.27) than control exosomes (P<0.001). RT-PCR showed that the relative expression of NLRP3 mRNA of PRE cells in experimental group and control group were 1.000±0.069 and 0.2±0.01, respectively, the difference was significant (t=12.20, P<0.001). Conclusion The expression IL-1β, IL-18 and caspase-1 and NLRP3 mRNA were upregulated by exosomes secreted by blue light damaged-RPE cells.
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Objective To observe the influence of down-regulation of HtrA1 expression by small interfering RNA on light-injured human retinal pigment epithelium (RPE) cells.Methods Cultured human RPE cells(8th-12th generations)were exposed to the blue light at the intensity of (2000 ± 500) Lux for 6 hours to establish the light injured model.Light injured cells were divided into HtrA1 siRNA group,negative control group and blank control group.HtrA1 siRNA group and negative control group were transfected with HtrA1 siRNA and control siRNA respectively.The proliferation of cells was assayed by CCK-8 method.Transwell test was used to detect the invasion ability of these three groups.Flow cytometry was used to detect the cell cycle and apoptosis.The expression of HtrA1 and vascular endothelial growth factor (VEGF)-A was detected by real time-polymerase chain reaction and Western blot respectively.Results The mRNA and protein level of HtrA1 in the light injured cells increased significantly compared to that in normal RPE cells (t=17.62,15.09;P＜0.05).Compared with negative control group and blank control group,the knockdown of HtrA1 in HtrA1 siRNA group was associated with reduced cellular proliferation (t=6.37,4.52),migration (t =9.56,12.13),apoptosis (t =23.37,29.08) and decreased mRNA (t=17.36,11.32,7.29,4.05) and protein levels (t=12.02,15.28,4.98,6.24) of HtrA1 and VEGF-A.Cells of HtrA1 siRNA group mainly remained in G0/G1 phase,the difference was statistically significant (t=6.24,4.93;P ＜0.05).Conclusion Knockdown of HtrA1 gene may reduce the proliferation,migration capability and apoptosis of light-injured RPE cells,and decrease the expression of VEGF-A.
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Objective To investigate the effects of FTY720 on retinal photoreceptor cells and microglial following light-induced degeneration in rat retina.Methods 120 Sprague-Dawley rats were randomly divided into four groups including FTY720 group,solvent control group,model group and normal group.The rats of normal group were not intervened.The FTY720 group,solvent control group and model group establish retinal light injury mode.FTY720 was injected into abdominal cavity of the rats in FTY720 group 0.5 hours before light exposure.50％ dimethylsulfoxide was injected into abdominal cavity of the rats in solvent control group.The expressions of microglial cells in rat retinal were quantified using flow cytometry,the expressions of interleukin (IL)-1β were examined by enzyme-linked immuno sorbent assay at 6 hours,1 day,3 days,7 days after light exposure.The apoptosis of retinal photoreceptor cells were measured by terminal-deoxynucleoitidyl transferase mediated nick end labeling at 1 day after light exposure.The morphological change of retinal were viewed by haematoxylin and eosin staining at 7 days after light exposure.Results The expressions of microgilal and IL-1β began to rise at 1 day after light exposure,reached at peak at 3 days and decreased at 7 days.The expressions of IL-1βand microglial in FTY720 group were significantly lower than solvent control group and model group,but higher than normal group (P＜0.05).One day after exposure to light,the apoptosis cell ratio in normal group,model group,solvent control group and FTY720 group were 0,(87.66 ± 2.50) ％,(86.00 ± 2.44) ％,(49.66 ± 2.80) ％.The apoptosis cell in FTY720 group were higher than normal group,lower than solvent control group and model group (P＜0.05).Seven days after exposure to light,the retinal in normal group was structured and the cell was arranged well,the cell in solvent control group and model group was irregular arrangement and the outer nuclear layer (ONL) was thin after light exposure.The thickness of the ONL in FTY720 group was significantly higher than solvent control group and model group,below normal group.Conclusion FTY720 can prevents retinal photoreceptor cells from apoptosis and inhibits activation of microglial.
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Objective To evaluate the clinical efficiency of intermittent photic stimulation (IPS) with pattern and red color plastic plates in video-electroencephalography(EEG).Methods Three hundred and fifty-eight patients hospitalized in Wuhan Children's Hospital from March 2013 to March 2014 were selected,and they were examined by using stroboscope with a red plastic plate,a dots printed plastic plate,and ordinary white flicker for photic driving response (PDR),photoparoxysmal responses (PPR),photoconvulsive response (PCR).The results of patients with PDR,PPR,PCR were analyzed.Results The PDR synchronously evoked by the three flickering patterns were in 29 cases,and the amplitude of photic drivings evoked by ordinary white flicker and red flicker were higher than that of flickering dot pattern [(30.294 ± 7.767) μV,(31.103 ± 8.920) μV vs (24.436 ± 8.075) μV],and there were significant differences(t =2.983,2.815,P =0.003,0.008).However,there was no significant difference between ordinary white flicker and red flicker (t =0.368,P =0.710).The PPR evoked were in 17 cases,and 16 cases (94.12％) of them were evoked by red color,while 10 cases (58.82％) wcre evoked by white light,and 1 case only evoked by flickering dot pattern.However,stronger intensity and longer duration time of PPR were evoked by red color than by white light.In 3 patients with positive PCR,the epileptic seizure was more likely to be evoked by red color or pattern plastic plate.Conclusions IPS with red and pattem plastic plate is more potent in eliciting photosensitive epilepsy in video-EEG than the ordinary white light.Moreover,it could reduce the discomfort of eyes without influencing PDR in comparison to the ordinary white light.
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Objetivo: Avaliar a Visão Funcional de crianças de zero a 5 anos e 11 meses de idade, após diagnóstico oftalmológico de Baixa Visão, para identificar a necessidade de Estimulação Visual no grupo estudado do Serviço de Estimulação Visual/VSN/OFTALMOLOGIA/HC/FCM/UNICAMP. Materiais e Métodos: Trata-se de estudo transversal analítico, aprovado pelo Comitê de Ética em Pesquisa, nº 1025/2010. Foi utilizado instrumento de Avaliação da Visão Funcional Infantil, organizado após estudos na literatura de autores nacionais e internacionais, na busca por avaliações da visão funcional que contemplassem a necessidade do serviço. Considerando-se as diferentes faixas etárias infantis propostas neste estudo, com n = 143, ponderou-se sobre a efetividade de algumas avaliações pesquisadas, organizando-se instrumento avaliatório, com tópicos, desenvolvidos de maneira a se obter respostas visuais eficientes para determinar condutas em Estimulação Visual. O Instrumento de Avaliação da Visão Funcional Infantil foi aplicado em grupo controle, com mesmo n (n=143) para sua validação. Resultados: As afecções oftalmológicas, responsáveis pelas deficiências visuais do grupo estudado foram: Retinopatia da Prematuridade, Afecções de Nervo Óptico, Deficiência Visual Cortical, Coriorretinite Macular Infecciosa, Malformações Oculares, Catarata Infantil, Degenerações Primárias da Retina, Glaucoma Congênito, Ceratopatias e Trauma Ocular ou Orbitário. A distribuição por idades foi determinada pela proximidade de respostas visuais esperadas para cada faixa etária deste estudo. Em relação ao Desenvolvimento Neuro Psico Motor (DNPM), 44 (30%) crianças apresentavam Bom desenvolvimento Neuro Psico Motor (BDNPM) e 99 (70%) Retardo no Desenvolvimento Neuro Psico Motor (RDNPM). No grupo controle, 2 crianças (1,4%) apresentaram RDNPM.
Objective: To evaluate the Functional Vision in children between zero and 5 years and 11 months old, after ophthalmological diagnosis of Low Vision, in order to identify the necessity of Visual Stimulation in the studied group from the Visual Stimulation Service/VSN/OPHTHALMOLOGY/HC/FCM/UNICAMP. Materials and Methods: This is a transversal analytical study, approved by the Research Ethics Committee, nº 1025/2010. It was used an Instrument for Functional Vision Evaluation for Children, organized after studies in the literature of national and international authors, in the search for functional vision evaluations which addressed the need for the service. Considering the different infant ages proposed on this study, with n = 143, the effectiveness of some evaluations surveyed were pondered, resulting in the organization of an evaluation instrument, with topics, developed in order to obtain efficient visual answers to determine Visual Stimulation conducts. The Instrument for Functional Vision Evaluation was applied in the Control Group, with similar n (n=143) for its validation. Results: The ophthalmologic diseases, responsible for the visual deficiencies of the studied group were: Retinopathy of Prematurity, Optical Nerve Disorder, Cortical Visual Deficiency, Infectious Macular Chorioretinitis, Ocular Malformations, Child Cataract, Retinal Primary Degenerations, Congenital Glaucoma, Ceratopatias and Ocular or Orbital Trauma. The age distribution was determined by the proximity of visual responses expected for each group age on this study. Regarding to the Psycho Neuro Motor Development (PNMD), 44 (30%) of the children presented Good Psycho Neuro Motor Development (GPNMD) and 99 (70%) presented Retardation of Psycho Neuro Motor Development (RPNMD).
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Humans , Male , Female , Infant, Newborn , Infant , Child, Preschool , Cross-Sectional Studies , Eye Health Services , Vision, Low/diagnosis , Diagnostic Techniques, Ophthalmological , Hospitals, University , Photic Stimulation , Visual AcuityABSTRACT
OBJETIVO: Desenvolver um método e um dispositivo para quantificar a visão em candela (cd). Os estudos de medida da visão são importantes para todas as ciências visuais. MÉTODOS: É um estudo teórico e experimental. Foram descritos os detalhes do método psicofísico e da calibração do dispositivo. Foram realizados testes preliminares em voluntários. RESULTADOS: É um teste psicofísico simples e com resultado expresso em unidades do sistema internacional de medidas. Com a descrição técnica será possível reproduzir o experimento em outros centros de pesquisa. CONCLUSÃO: Os resultados aferidos em intensidade luminosa (cd) são uma opção para estudo visual. Esses resultados possibilitarão extrapolar medidas para modelos matemáticos e para simular efeitos individuais com dados aberrométricos.
PURPOSE: To develop a method and a device for vision measurement in candela (cd). Vision measurement studies are important to all visual sciences. METHODS:It is a theoretical and experimental study. The details of psychophysical method and device calibration were described. Preliminary tests were performed on volunteers. RESULTS:It is a simple psychophysical test and results are expressed in International System of Units. With this technical description it will be possible to reproduce the experiment in others research centers. CONCLUSION: The results measured in luminous intensity (cd) are an option for visual studies. These results allow to extrapolate measurements for mathematical models and to simulate data for individual aberrometry effects.
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Humans , International System of Units/instrumentation , Vision Tests/methods , Algorithms , Equipment Design , Models, Theoretical , Pattern Recognition, Visual , Photic Stimulation , Psychophysics , Reproducibility of Results , Vision Tests/instrumentation , Visual Acuity/physiology , Visual Perception/physiologyABSTRACT
PURPOSES: To standardize and validate the technique of axonal electrovisiogram (AxEvg), defining its normative values and parameters and characterizing its findings in normal individuals. METHODS: We enrolled 140 normal individuals (280 eyes) divided into seven groups according to age, each one with 10 males and 10 females. The technique was based on monocular visual stimulation by a 0 dB intensity bright flash on Ganzfeld bowl at a presentation rate of 1.4 Hz. Golden cup electrodes were used and electrical waves were acquired after artifact rejection. For each amplitude and implicit time peak we calculated the mean, median, pattern deviation, minimum and maximum values and 95 percent confidence interval. RESULTS: Monocular visual stimulation with bright flash under mesopic conditions was the standard technical procedure established. The normal AxEvg waveform consists of an initial positive wave (named P1, with mean amplitude of 2.0 mV and mean implicit time peak of 23.1 ms) followed by a negative wave (named N1, with mean amplitude of -3.9 mV and mean implicit time peak of 41.4 ms). No significant differences were observed between males and females or between right and left eyes, but there was an increased P1 and N1 implicit time peaks according to age. Implicit time characteristics suggest that P1 wave represents an optic nerve electrical potential and N1 wave represents an inner retinal layers potential. CONCLUSIONS: AxEvg can be considered a pre-chiasmatic visual evoked potential capable to reliably record the electrical activity of optic nerve and inner retina. The findings suggest that AxEvg may be useful as an electrophysiological test in the diagnosis of neuroretinal diseases.
OBJETIVOS: Padronizar e validar a técnica de realização do eletrovisuograma axonal (EVA), definir seus valores normativos e caracterizar os achados em indivíduos normais. MÉTODOS: Estudo descritivo com 140 indivíduos (280 olhos) normais. Os participantes foram divididos em sete grupos de acordo com a idade, cada qual com 10 indivíduos do sexo masculino e 10 do sexo feminino. Definiu-se como técnica de exame a estimulação monocular por flash luminoso com intensidade de 0 dB na cúpula de Ganzfeld a uma frequência de 1,4 Hz. Foram utilizados eletrodos com cúpula de ouro e foram analisados os traçados elétricos obtidos após rejeição de artefatos. Para cada amplitude e tempo de culminação foram calculados a média, a mediana, o desvio-padrão, os valores mínimo e máximo e o intervalo de confiança de 95 por cento representando uma faixa de normalidade para os valores. RESULTADOS: A técnica de exame padronizada foi a estimulação visual monocular por flash em condições mesópicas. O traçado normal do eletrovisuograma axonal consistiu numa onda positiva inicial (P1, com amplitude média de 2,0 mV e tempo de culminação médio de 23,1 ms) seguida de uma onda negativa (N1, com amplitude média de -3,9 mV e tempo de culminação médio de 41,4 ms). Não foram observadas diferenças significativas entre os sexos e entre os olhos direito e esquerdo, mas os tempos de culminação de P1 e de N1 aumentaram proporcionalmente com a idade. CONCLUSÕES: O eletrovisuograma axonal é um exame de potencial visual evocado pré-quiasmático, capaz de registrar de forma confiável e reprodutível a atividade elétrica do nervo óptico e da retina interna, podendo ser utilizado na propedêutica eletrofisiológica na investigação de lesões neurorretinianas.
Subject(s)
Adolescent , Adult , Child , Child, Preschool , Female , Humans , Infant , Male , Middle Aged , Young Adult , Axons/physiology , Evoked Potentials, Visual/physiology , Optic Nerve/physiology , Retina/physiology , Electroretinography , Photic Stimulation , Reference ValuesABSTRACT
Objective To assess the effects of 670nm LED (light-emitting diode) to protect the photoreceptor from the light-induced damage in a rat model. Methods 32 SD rats were randomly assigned to one of eight groups: untreated control group, the LED-treated control group, three groups of light-induced damage,and three groups of light-induced damage treated with LED. Light-induced damage result from exposing to constant light for 3 hours of different illuminations of 900,1800 and 2700 lx, respectively. The LED treatment (50 mW) was delivered for 30 minutes at 3 hours before the light damage and 0,24 and 48 hours after the light damage. Retinal function and morphology were measured by electroretinogram (ERG) and histopathology assay. Results The illumination of 900 lx for 3 hours did not damage the rat retina. The illumination of 1800 lx for 3 hours resulted in thinner ONL and no OS and IS. The ratio of damaged area/total retinal area was 0.48±0.12, the damaged thickness of ONL/normal ONL (L5) was 0.39±0.07,and the amplitude of ERG b wave was (431±120) μV. With the LED treatment the ratio of damaged area decreased (M6=0.17±0.12, P5/6=0.002), and the ratio of the damaged thickness of ONL also decreased (L6=0.22±0.09, P5/6<0.01), and the amplitude of ERG b wave increased to (1011±83) μV(P5/6 <0.001). The illumination of 2700 lx for 3 hours caused severed damage to the rat retina and the LED could not protect them significantly. Conclusions 670 nm LED treatment has an evident protective effect on retinal cells against light-induced damage, which may be a simple and effective therapy to prevent or to delay age-related maeular degeneration.
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OBJETIVOS: Desenvolver um sistema digital, com capacidade de induzir acomodação, para medida do diâmetro e formato da pupila para dez diferentes níveis de iluminação (LUX), variando do nível mesópico ao fotópico. MÉTODOS: Um sistema óptico para conjugar imagens da pupila iluminada por LED infravermelho e branco foi projetado e montado usando um capacete típico de oftalmoscópio e uma máscara típica de mergulhador como suporte e uma câmera CCD de alta resolução e sensibilidade. Algoritmos usando princípios de processamento de imagens foram implementados para leitura do arquivo de vídeo e a detecção automática do centro geométrico e diâmetro da pupila para cada quadro. RESULTADOS: Apresentamos dados preliminares deste sistema para um paciente voluntário. Os dados sobre posição horizontal (x), vertical (y) do centro geométrico e do diâmetro da pupila foram exportados para arquivos texto que podem ser impressos usando um programa convencional de planilha (Excel). O processo de acomodação é garantido por uma mira virtual (LED branco) localizada a 6 metros do olho do paciente e o nível de iluminação é precisamente controlado por uma placa eletrônica que alimenta o LED central que tem sua potência controlada pelo "software". CONCLUSÕES: Com o instrumento desenvolvido dados precisos da posição e tamanhos da pupila podem então ser obtidos estereoscopicamente (para ambas as pupilas e ao mesmo tempo) para qualquer paciente. Acreditamos que tal instrumento possa ser útil em algumas práticas oftálmicas onde as características geométricas da pupila sejam importantes.
PURPOSE: We developed a digital system with accommodation capacities for measurement of the diameter and shape of the in vivo pupil for 10 different levels of illumination intensity, varying from mesopic to photopic. METHODS: An optical system for conjugating images from an infrared and white light illuminated pupil was designed and mounted using an ophthalmoscope helmet and a typical diving mask as support for a high-resolution and sensitivity CCD. Using an IBM compatible computer sequences of video in AVI format were digitized for several seconds at a mean rate of 30 Hz. Algorithms using principles of image processing were implemented for detection of the pupil edges. RESULTS: We present preliminary results of this system for a voluntary patient. Data for the horizontal (x) and vertical (y) central position and for the diameter of the pupil were then exported to files that could be read by typical spread sheet programs (Excel). CONCLUSIONS: In this manner, precise data can be obtained stereoscopically (for both pupils at the same time) for any patient, given that the accommodation process is guaranteed by using a white LED virtual mire located 6 meters from the patient's eye. An electronic board precisely controls the level of illumination. We believe here developed instrument may be useful in certain ophthalmic practices where precise pupil geometric data are needed.
Subject(s)
Adult , Humans , Male , Adaptation, Ocular/physiology , Image Processing, Computer-Assisted/instrumentation , Photic Stimulation/methods , Pupil/physiology , Algorithms , Equipment Design , Fixation, Ocular/physiology , Iris/anatomy & histology , Lighting/methods , Mesopic Vision/physiology , Ophthalmoscopes , Optical Devices , SoftwareABSTRACT
Melatonin secretion from mammalian pineal glands is regulated by light stimulation by means of a complex neuroanatomical pathway that includes the retina, hypothalamic suprachiasmatic nucleus, intermediolateral nucleus of the thoracic spinal cord, and finally, the superior cervical ganglia. The purpose of this study was to analyze the changes in the pinealocytes and the blood vessel density of the pineal gland after eliminating photic stimulation in rats. Thirteen adult Sprague-Dawley rats were divided into 2 groups, Group I acted as control, and Group II was subjected to a retinal lesion, by means of alcohol injected bilaterally to both ocular bulbs. After 3 weeks, the glands of both groups were processed with hematoxilin-eosin (HE) and observed with an optic microscope. Group II results presented higher values in the number of pinealocytes and in the blood vessels observed. The differences with Group I was significant at p <0.01. These results give an indirect evidence of the effect that photic stimulation suppression has in the pineal gland in rats.
La secreción de melatonina por parte de glándula pineal de los mamíferos es regulada por la estimulación luminosa mediante complejas vías neuro anatómicas que incluyen la retina, el núcleo supraquiasmático hipotalámico, el núcleo intermediolateral de la médula torácica y finalmente el ganglio cervical superior. El propósito de este estudio fue analizar los cambios en la densidad de pinealocitos y vasos sanguíneos de la glándula pineal, luego de eliminar la estimulación fótica en ratas. Se utilizaron 13 ratas adultas Sprague Dawley divididas en 2 grupos, Grupo I actuó como control, y el Grupo II fue sometido a una lesión retiniana, por medio de alcoholización bilateral de ambos bulbos oculares. Luego de tres semanas las glándulas de ambos grupos fueron procesadas para hematoxilina-eosina y observadas al microscopio óptico. El grupo II presentó valores mayores en el número de pinealocitos y de vasos sanguíneos observados, las diferencias con el Grupo I fueron significativas con p<0.01. Estos resultados entregan una evidencia indirecta del efecto que la supresión de la estimulación fótica tiene en la glándula pineal en ratas.
Subject(s)
Adult , Animals , Female , Rats , Pineal Gland/anatomy & histology , Pineal Gland/metabolism , Pineal Gland , Rats, Sprague-Dawley/anatomy & histology , Rats, Sprague-Dawley/metabolism , Superior Cervical Ganglion/metabolism , Superior Cervical Ganglion , Lighting/methods , Melatonin/metabolism , Melatonin , RetinaABSTRACT
INTRODUÇÃO: Embora a fotostimulação intermitente (FEI) seja rotineiramente utilizada nos laboratórios de eletrencefalografia (EEG), raramente é utilizada de forma padronizada. A FEI é um método de ativação utilizado no EEG de rotina que pode desencadear tanto respostas fisiológicas quanto potencialmente patológicas. Historicamente, o termo fotossensibilidade se refere às respostas anormais à estimulação com luz estroboscópica durante o registro do EEG. OBJETIVO: O objetivo desta publicação é revisar os aspectos diagnósticos do procedimento da FEI, baseados no encontro de consenso realizado em Heemstede na Holanda, em 1996, com o propósito de facilitar e padronizar a detecção de pacientes fotossensíveis.
INTRODUCTION: Although intermittent photic stimulation (IPS) is a widespread and routinely used procedure in EEG laboratories, only relatively recently has a standardization of the IPS method been proposed. IPS is an activation method used during EEG procedure that may trigger either physiological or potentially pathological responses. Historically, the term photosensitivity is referred to abnormal responses to stroboscopic light during EEG. OBJECTIVE: The purpose of this publication was to provide an overview of the diagnostic aspects of IPS procedure, based on data presented at Consensus Meetings held in Heemstede, the Netherlands, in 1996, with the purpose of facilitating the detection of photosensitive patients.
Subject(s)
Humans , Photosensitizing Agents , Photic StimulationABSTRACT
Objective:To investigate the expression of endoplasmic reticulum stress proteins in photoreceptor apoptosis in light-induced retinal degeneration. Methods: Exposure to excessive levels of light induced photoreceptor apoptosis and had been previously used as a model for the study of retinal degeneration. Photoreceptor apoptosis was detected by terminal dUTP transferase nick end labeling (TUNEL). The protein expression levels of ER stress sensors including glucose-regulated protein-78 (GRP78/BiP), caspase-12, phospho-eukaryotic initiation factor 2? (eIF2?) and phospho-double-stranded RNA-activated protein kinase-like endoplasmic reticulum kinase (PERK) were examined by immuno-fluorescence and Western blot analysis. Results: Following light exposure, the protein expression levels of GRP78/BiP, caspase-12, phospho-eIF2? and phospho-PERK were up-regulated in a time dependent manner. The up-regulation of these proteins coincided with or preceded the photoreceptor apoptosis. At the peak of their expression, they were mainly located in the photoreceptor inner segments and/or outer nuclear layers (ONL). Conclusion: Activation of endoplasmic reticulum stress proteins appears to play an important role in light-induced retinal degeneration. Therefore endoplasmic reticulum stress modulators could become a strong candidate for a therapeutic agent in treatment of these diseases.
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Aim This study aimed to assess the protection of recombinant human erythropoietin (rhEPO) in light-induced injuries in human retinal pigment epithelial(RPE)cells by researching the inhibition of rhEPO for apoptosis in human RPE cells by light-induced injuries.Methods Cultured human RPE cells were exposed to light of 8 w (2 000?500) lux for 12hours,then the culture were stopped at 24 hours after 12hours light stimulation. The effect of inhibiting apoptosis of rhEPO was detected by AnnexinV-flunorescein isothiocyanate/Propidium iodium labeling and flow cytometry. The enzyme linked immunosorbant assay(ELISA)and immunocytochemical staining were used to assess the expressions of caspase-3 and Bcl-2 treated by different doses of rhEPO in light-induced injury on human RPE cells and research the protective mechanism of rhEPO by adding AG490(the special inhibitor of Jak2).Results There was a obviously increased effects on inhibiting apoptosis in every rhEPO group, which was the most conspicuous in 40 IU?ml-1 rhEPO group,and the value was (4.93?1.45)?ml-1. The decrease of expression of caspase-3 was most obvious in 40 IU?ml-1 rhEPO group, and the value was (0.125?0.029) ?g?L-1. The increase of expression of Bcl-2 was the most obvious in 40 IU?ml-1 rhEPO group and the value was 168.21?3.87. But these effects on inhibiting apoptosis in rhEPO group were restrained by adding AG490, the value of apoptosis was (11.29?2.11)?ml-1 and the density of caspase-3 increased to (0.362?0.042) ?g?L-1,the expression of Bcl-2 dropped.Conclusion It is suggested that rhEPO can inhibit the apoptosis of human RPE cells in the light-induced injuries and inhibit the expression of caspase-3 and up-regulate the expression of Bcl-2, so rhEPO can protect the light-induced injuries for human RPE cells. Its protective mechanism is accomplished principally by the pathway of combining EPO with EPOR ,then the combination activates Jak2.
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Objective To observe the effect of blue light on apoptosis of cultured human retinal pigment epithelial (RPE) cells in vitro. Methods Human RPE cells were exposed to blue light, and the cells were divided into 3 groups: group A, with various intensity of illumination; group B: with same intensity but different time of illumination; group C: with same intensity and time of illumination but different finish time of the culture. The apoptosis of RPE cells was observed by TdT-dUTP terminal nick-end labeling (TUNEL) and annexin V-fluoresein isothiocyanate (FITC)/propidium iodide (PI) flow cytometry, and transmission electron microscopy. Results The positive cells stained by TUNEL shrinked and turned round, whose nuclei concentrated and congregated like the crescent or hat. Cracked nuclei and membrane bleb were found. Swollen mitochondrial, disappeared inner limiting membrane of mitochondria, and dilation of the rough endoplasmic reticulum with metabolite were observed by transmission electronmicroscopy. In group A, mild damage of RPE cells was found when the threshold value of the intensity of illumination was less than (500?100)lx, and the apoptosis and necrosis of RPE cells aggravated as the intensity of illumination increased; in group B, as the time of illumination extended, the number of apoptotic RPE cells didn′t increase while the necrosis increased; in group C, 6 and 12 hours after illumination, apoptosis of cells was the main injury, while apoptosis with necrosis was found and necrotic cells increased as the time of illumination was prolonged. Conclusions Illumination with blue light may cause damages of human RPE cells in vitro, with the modalities of apoptosis, apoptotic necrosis and necrosis. The extent of injury is dependent on intensity and duration of the illumination.
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Objective This test is focused on functional magnetic resonance imaging(fMRI) of visual cortex by using echo planar imaging(EPI) and blood oxygenation level dependent(BOLD) contrast. Methods 36 normal volunteers and 17 patients with lesions at occipital lobe were included in this test. The echo planar images of the occipital area were acquired at visual stimulation and rest phases. Results The primary visual cortex was located at the bilateral calcarine cortex, which belonged to Brodmann area 17. The functional areas showed displacement due to the mass effect of lesions near calcarine cortex in 3 patients. Conclusion fMRI can be used to study human functional cortex. A preliminary location of visual cortex can be acquired through visual stimulation. The invasion of the intracranial massive lesions to functional areas the disappearance of functional activation. The mass effect of intracranial lesions may lead to deformation or displacement of the near functional areas.
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Objective To research the physiology of visual cortex activated by rotating grating with functional-MRI(fMRI), and to identify the components of the activation. Methods Functional MRI was performed in 9 healthy volunteers by using GRE-EPI sequences on a 1.5 T MR scanner. In the block designing, rotating grating, static grating, and luminance were plotted as task states, while static grating, luminance, and darkness were set as control states. The stimuli tasks included six steps. Imaging processing and statistical analysis was carried out off-line using SPM99 in single-subject method. Results Some respective areas of visual cortex were activated by the various stimuli information supplied by rotating grating. The strong activation in the middle of occipital lobe located at primary vision area was related to the stimuli of white luminance. Its average maximum points were at 13,-98,-2 and 11, -100,-4. The bilateral activations of Brodmann 19th area located at MT area were related to visual motion perception. Its average maximum points were at 46,-72,-2 and -44,-74, 0. The mild activation in the middle of occipital lobe was related to form perception. Its average maximum points were at -12,-98,-6 and -16,-96, (-6.) Conclusion The plotting of control state is important in bock design. The effective visual information of rotating grating includes components of luminance, visual motion perception, and form perception. FMRI has potential as a tool for studying the basic physiology of visual cortex.