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Sample records for degenerativas da retina

  1. Avaliação ocular multimodal em doenças heredodistróficas e degenerativas da retina Multimodal fundus imaging in heredodystrophic and degenerative diseases of the retina

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    Daniela Cavalcanti Ferrara

    2009-10-01

    Full Text Available A tomografia de coerência óptica incorporou-se gradativamente ao contemporâneo arsenal diagnóstico em Oftalmologia, passando a exercer papel fundamental na investigação e condução de doenças oculares, particularmente na especialidade de Retina e Vítreo. A disponibilização comercial da nova geração de aparelhos, chamada de tomografia de coerência óptica "espectral", baseada em conceito físico distinto que permite a aquisição de imagens em alta velocidade, marcou o início de uma nova era desta tecnologia de investigação auxiliar. Adicionalmente, sua recente combinação com o oftalmoscópio de varredura a laser confocal (confocal scanning laser ophthalmoscope vem propiciando a aquisição de imagens tomográficas guiadas em tempo real pelos diferentes modos de imagem (autofluorescência de fundo, reflectância com luz "infravermelha" e angiografia com fluoresceína ou indocianina verde. A avaliação ocular multimodal (multimodal fundus imaging permite a correlação real e minuciosa de achados da morfologia retiniana e do epitélio pigmentar com dados de estudos angiográficos e de autofluorescência ou reflectância, propiciando assim inferências valiosas sobre a fisiologia do tecido. Neste artigo, discutimos brevemente as possíveis implicações da avaliação ocular multimodal na prática da especialidade de Retina e Vítreo.Optical coherence tomography was progressively incorporated to the contemporary diagnostic arsenal in Ophthalmology, playing a crucial role in the diagnosis and management of eye diseases, particularly in the specialty of retina and vitreous. The commercial availability of the new generation of devices, coined "spectral" optical coherence tomography, which is based in a distinct physical concept that permits high-speed image acquisition, launched a new era for this investigative ancillary tool. In addition, the recent combination of this new technology with a confocal scanning laser ophthalmoscope

  2. Classificação diagnóstica dos portadores de doenças degenerativas de retina, integrantes dos grupos Retina São Paulo e Retina Vale do Paraíba Diagnostic classification of retinal degenerative diseases São Paulo and Vale Retina groups

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    Nichard Unonius

    2003-08-01

    Full Text Available OBJETIVO:Organizar um banco de dados regional de todos os indivíduos portadores de doenças degenerativas da retina, com o objetivo de classificar cada paciente de acordo com o tipo de distrofia e padrão de herança. MÉTODOS: Durante o encontro do Grupo Retina São Paulo no dia 5 de maio de 2001, duzentas e quarenta e três pessoas foram registradas, sendo que parte forneceu dados de antecedentes oculares, pessoais e familiares e árvore genealógica. Noventa e três pacientes foram questionados quanto a idade, origem, tipo de distrofia, história familiar e árvore genealógica, tipo de herança, outras anomalias sistêmicas e exames complementares. Foram classificados quanto ao diagnóstico e padrão de herança. RESULTADOS: Dos duzentos e quarenta e três pacientes registrados, as distrofias encontradas foram retinose pigmentária, doença de Stargardt, síndrome de Usher, amaurose congênita de Leber e coroideremia. Quanto à divisão por doença dos 93 pacientes argüidos, havia 62 pacientes com retinose pigmentária, 13 com doença de Stargardt, 13 com síndrome de Usher, três com amaurose congênita de Leber e dois com coroideremia. Dos pacientes com retinose pigmentária, o padrão de herança detectado foi autossômico dominante em quatro casos (7%, autossômico recessivo em vinte casos (32%, ligado ao cromossomo X recessivo em sete casos (11%, caso isolado em vinte e nove (47% e padrão indeterminado em dois (3%. Para a doença de Stargardt três indivíduos (23% seguiam o padrão de herança autossômico recessivo e dez (77% eram casos isolados. Dos treze pacientes com síndrome de Usher, oito (61,5% apresentavam herança autossômica recessiva, quatro (31% eram casos isolados e um (7,5% tinha o padrão de herança indeterminado. Os dois pacientes com coroideremia seguiam o padrão de herança ligado ao X recessivo. Para amaurose congênita de Leber, um paciente (33,5% tinha padrão autossômico recessivo de herança e dois (66

  3. Degenerações periféricas da retina em pacientes candidatos à cirurgia refrativa Peripheral retina degeneration in patients who are candidates for refractive surgery

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    Paulo Henrique de Avila Morales

    2001-02-01

    Full Text Available Objetivo: O objetivo desse estudo é verificar em indivíduos míopes candidatos à cirurgia refrativa a prevalência dos diferentes tipos de lesões retinianas periféricas degenerativas de acordo com o tipo de miopia. Métodos: De forma prospectiva, no período de um ano, foram examinados os olhos dos pacientes no Setor de Cirurgia Refrativa do Departamento de Oftalmologia da Universidade Federal de São Paulo - Escola Paulista de Medicina que durante a sua consulta inicial apresentassem refração com equivalente esférico superior ou igual a -1,00 dioptria esférica, e não tivessem antecedentes pessoais de doença ou cirurgia ocular no período. Foi investigada a existência de lesões e/ou degenerações periféricas predisponentes ao descolamento regmatogênico de retina. Resultados: O grupo foi composto, em sua maioria, por adultos jovens (média de idade de 31 anos. Foram observados olhos com miopia baixa (263 olhos, 31%, moderada (300 olhos, 36% e alta (277 olhos, 33%; em 35,4% dos pacientes (27% dos olhos foram encontradas degenerações periféricas, sendo o branco com e sem pressão a alteração mais freqüente (23,4% dos pacientes ou 17,5% dos olhos. Entre as lesões predisponentes ao descolamento regmatogênico da retina, a mais encontrada foi a degeneração em treliça (8,6% dos pacientes ou 6% dos olhos. Conclusões: As alterações periféricas predisponentes ou não ao descolamento regmatogênico de retina apresentaram aumento de prevalência de acordo com o aumento do grau de miopia, com exceção das roturas. Todos os pacientes com miopia alta e candidatos à cirurgia refrativa devem ter a periferia retiniana de ambos os olhos examinada.Purpose: To verify, in myopic individuals who are candidates for refractive surgery, the prevalence of different types of peripheral degenerative lesions of the retina, according to the type of myopia. Methods: Prospectively, during a one-year interval, we examined the eyes of patients in

  4. Variação de conduta cirúrgica em doença degenerativa da coluna lombar Variación de conducta quirúrgica en la enfermedad degenerativa de la columna lumbar Surgical decision making variation in degenerative lumbar spine

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    Luís Felipe Pamplona Novaes

    2009-03-01

    Full Text Available OBJETIVO: examinar a variação da decisão de tratamento entre cirurgiões de coluna para cinco situações clínicas que envolvam condições degenerativas da coluna lombar e determinar se fatores como tipo de treinamento do cirurgião, experiência e idade são como preditores da tomada de decisões para cada caso. MÉTODOS: dez ortopedistas e dez neurocirurgiões, de diferentes idades, responderam questões sobre a necessidade de cirurgia, opções de via de acesso, realização de descompressão, realização de artrodese, com ou sem instrumentação, para cinco casos de doença degenerativa da coluna lombar por meio de informações da história, exame clínico e exames de imagem adequados (todos tiveram acesso às mesmas informações e foram orientados a responder com base em sua prática clínica. Os casos foram: discopatia com instabilidade vertebral em um paciente jovem; hérnia de disco extrusa em paciente jovem; estenose de canal vertebral múltiplos níveis sem deformidade; estenose canal múltiplos níveis com cifoescoliose degenerativa; hérnia de disco com artrose facetária. Na análise estatística foi utilizado o teste "t" de student para comparar o fator especialidade e médias de idade com as variáveis de tratamento (significativo quando pOBJETIVOS: examinar la variación de la decisión de tratamiento entre cirujanos de la columna para cinco escenarios clínicos involucrando condiciones degenerativas de la columna lumbar. Determinar si el tipo del entrenamiento del cirujano, experiencia y edad sirve como factores predictivos en la toma de decisiones de cada caso. MÉTODOS: diez ortopedistas y diez neurocirujanos de diferentes edades respondieron un cuestionario sobre la necesidad de cirugía, opciones de vías de acceso, realización de descompresión, realización de artrodesis con o sin instrumentación para 5 casos de enfermedad degenerativa de la columna lumbar por medio de informaciones de la historia, examen cl

  5. Psicoses degenerativas: fasofrenias de Kleist

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    Roberto Tomchinsky

    1959-06-01

    Full Text Available O autor procura resumir os estudos de Kleist e seus colaboradores referentes às psicoses degenerativas ou fasofrenias, grupo constituído por psicoses atípicas, benignas, fásicas e cíclicas, que apresentam sintomatologia rica e variada devido a seus caracteres heredológicos mistos e atenuados. A princípio estas doenças foram consideradas como aparentadas aos grandes grupos endógenas - psicose maníaco-depressiva, paranóia e epilepsia - e foram classificadas como colaterais aos mesmos, por motivações práticas e históricas, como assinalou Kleist, para o qual os caracteres benignos seriam devidos à degeneração da morbilidade genética da doença. São apresentadas as diversas sistematizações dessas doenças com comentários sumários sôbre os vários quadros clínicos. O autor insiste na importância da identificação destas psicoses desde que representam cêrca de 25% das doenças mentais endógenas. Além disso, como remitem sem deixar defeito, não devem ser confundidas com a esquizofrenia como ocorre freqüentemente. Seu diagnóstico correto evitará também exageros de apreciação quanto à eficácia de novas drogas terapêuticas que dia a dia surgem no campo psiquiátrico.

  6. Maturação funcional da retina em bebês prematuros

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    Adriana Berezovsky

    2007-06-01

    Full Text Available A retina humana ainda não está totalmente desenvolvida no nascimento. Só após o nascimento é que ocorrem mudanças anatômicas como o aumento na densidade de cones centrais e o alongamento do segmento externo dos fotorreceptores. As mudanças funcionais que ocorrem na retina com a maturação no primeiro ano de vida podem ser avaliadas pela técnica do eletrorretinograma de campo total, que representa a atividade somada da retina distal em resposta à luz. Abordaremos aspectos da maturação funcional da retina avaliada pelo eletrorretinograma em bebês prematuros.

  7. Meduloepitelioma teratóide da retina: relato de caso Teratoid medulloepithelioma of the retina: case report

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    Ramon Coral Ghanem

    2004-06-01

    Full Text Available O meduloepitelioma é um tumor intra-ocular congênito originário do epitélio medular primitivo que, por sua vez, é responsável pela formação do epitélio não pigmentado do corpo ciliar. Ocorre geralmente na infância, de forma unilateral, acometendo o corpo ciliar. O objetivo deste trabalho é documentar um caso raro de meduloepitelioma teratóide originário da retina. Paciente de nove anos, feminina, apresentava baixa acuidade visual (AV, estrabismo e leucocoria no olho esquerdo (OE. A AV era de 1,0 no olho direito e movimentos de mão no OE. Foi observada tumoração retrocristaliniana branco-acinzentada no OE, aparentemente subretiniana, vascularizada, de grande extensão, com alterações císticas na sua superfície. Foram realizadas tomografia de crânio e órbitas e ecografia ocular. A paciente foi submetida à enucleação com suspeita clínica de retinoblastoma. Pelo aspecto histopatológico foi feito o diagnóstico de meduloepitelioma teratóide benigno originário da retina. Na maioria dos casos apresentados na literatura o meduloepitelioma tem origem a partir do epitélio não pigmentado do corpo ciliar. No nosso caso, a neoplasia parece ter tido origem a partir da retina, já que os cortes revelaram epitélio do corpo ciliar preservado e não foi reconhecida a estrutura normal da retina. Embora o tumor apresentado neste relato tenha sido classificado como benigno, o fato de ser lesão de grandes proporções e de crescimento aparentemente recente, justifica a conduta cirúrgica empregada. O tratamento do meduloepitelioma deve objetivar a intervenção cirúrgica precoce, na tentativa de se evitar a disseminação extra-ocular.Medulloepithelioma is a congenital intraocular tumor that usually arises from the primitive medullary epithelium that is destined to form the nonpigmented ciliary epithelium of the ciliary body. It occurs most frequently in early childhood and is unilateral. This report documents a rare case of

  8. Ataxia heredo-degenerativa associada a hipoacusia

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    José Antonio Levy

    1964-06-01

    Full Text Available São estudados três irmãos, respectivamente com 16, 8 e 6 anos de idade, todos do sexo masculino, com ataxia heredo-degenerativa associada, em dois dêles, a hipoacusia. Nos antecedentes há referência a moléstia semelhante em um avô e um tio-avô. É discutido o diagnóstico diferencial com a moléstia de Pièrre Marie, a doença de Charcot-Marie-Tooth, a síndrome de Refsum e a neurite intersticial hipertrófica, sendo acentuada a semelhança dos casos estudados com a moléstia de Friedreich. São feitos comentários à associação da doença de Friedreich com distúrbios da audição.

  9. Myopathy associated with pigmentary degeneration of the retina and high protein content of cerebrospinal fluid Miopatia associada a degeneração pigmentar da retina e hiperproteinorraquia

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    José Antonio Levy

    1974-06-01

    Full Text Available The cases of two brothers suffering from a myopathy associated with pigmentary degeneration of the retina and increase of protein content of the cerebrospinal fluid are reported.Foram estudados dois pacientes, filhos de pais não consanguíneos, com quadro miopático, iniciado na segunda década da vida, com predomínio na musculatura das cinturas e da face. Em ambos os casos havia degeneração pigmentar da retina e aumento da taxa protéica no líquido cefalorraqueano.

  10. Diagnostic classification of retinal degenerative diseases São Paulo and Vale Retina groups

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    Unonius, Nichard; Farah, Michel Eid; Sallum, Juliana M. Ferraz

    2003-01-01

    OBJETIVO:Organizar um banco de dados regional de todos os indivíduos portadores de doenças degenerativas da retina, com o objetivo de classificar cada paciente de acordo com o tipo de distrofia e padrão de herança. MÉTODOS: Durante o encontro do Grupo Retina São Paulo no dia 5 de maio de 2001, duzentas e quarenta e três pessoas foram registradas, sendo que parte forneceu dados de antecedentes oculares, pessoais e familiares e árvore genealógica. Noventa e três pacientes foram questionados qua...

  11. Avaliação clínica e funcional no pré-operatório de doenças degenerativas da coluna vertebral Evaluación clínica y funcional en el preoperatorio de patologías degenerativas de columna Clinical and functional evaluation in preoperative period of degenerative disease spine surgery

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    Asdrubal Falavigna

    2009-09-01

    Full Text Available OBJETIVO: a utilização de instrumentos de avaliação clínica e funcional nos pacientes com doenças da coluna vertebral pode determinar a evolução e predizer o desfecho pós-operatório. O objetivo deste estudo foi descrever a metodologia de avaliação de doenças degenerativas espinhais e verificar os resultados. MÉTODOS: após a indicação de tratamento cirúrgico nos pacientes com doenças das colunas lombar e cervical, os mesmos foram informados dos objetivos do estudo e convidados a participar. Os questionários foram respondidos no consultório médico, onde possíveis dúvidas surgidas durante o preenchimento eram esclarecidas por uma pessoa treinada não envolvida com a cirurgia. Todos os instrumentos de avaliação usados eram autoaplicativos. Foram utilizados a escala numérica de dor, o Questionário de Qualidade de Vida SF-36, o Questionário de Evitação por Medos e Crenças (FABq, o Inventário de Depressão de Beck (BDI, a Escala de Depressão e Ansiedade Hospitalar (HAD, o Índice de Incapacidade Oswestry (ODI e o Índice de Disfunção Relacionado ao Pescoço (NDI. RESULTADOS: foram avaliados 220 pacientes com doenças da coluna lombar e 32 da cervical. A prevalência de depressão segundo o BDI foi de 28,0% e de 31,2% em pacientes com doença cirúrgica lombar e cervical, e a prevalência de ansiedade pelo HAD-A de 40,1% e 46,9%, respectivamente. A média do ODI foi de 46,5, e a do NDI, de 25,4. Quanto ao preenchimento dos questionários, a maioria dos pacientes, uma vez instruídos, não apresentou dificuldades em finalizá-los. O tempo médio de preenchimento de todos os instrumentos foi de 25 a 35 minutos. CONCLUSÕES: a utilização de instrumentos validados para avaliação dos pacientes com doenças degenerativas vertebrais é exequível e deve ser estimulada entre os cirurgiões que atuam no âmbito da coluna vertebral.OBJETIVO: la utilización de instrumentos de evaluación clínica y funcional de patolog

  12. Resultados do tratamento cirúrgico da artropatia degenerativa do manguito rotador utilizando hemiartroplastia-CTA® Results of surgical treatment of denerative arthropathy of the rotator cuff using hemiarthroplasty-CTA®

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    Rômulo Brasil Filho

    2012-02-01

    Full Text Available OBJETIVO: Avaliar os resultados da artroplastia parcial de ombro tipo CTA® para o tratamento da artropatia degenerativa do manguito. MÉTODOS: De dezembro de 2006 a junho de 2009, 23 ombros de 23 pacientes foram submetidos à artroplastia parcial tipo CTA® para o tratamento de artropatia por lesão do manguito rotador. O tempo de seguimento pós-operatório variou de seis a 35 meses. A idade média foi de 74,1 anos. Houve predomínio do sexo feminino em 78,3% dos casos. O membro direito foi acometido em 18 pacientes. Todos os pacientes foram submetidos, sem melhora dos sintomas, ao tratamento fisioterápico prévio por pelo menos seis meses e foram submetidos à cirurgia pela mesma equipe cirúrgica. Nenhum dos pacientes havia realizado cirurgia prévia no ombro afetado. A avaliação dos pacientes no seguimento pós-operatório seguiu os critérios do escore da UCLA. RESULTADOS: Verificou-se melhora da dor em todos pacientes após a artroplastia. Pelo escore da UCLA, a média de pontos em relação à dor foi de 9,22 (variando de 10 a oito. Quanto à função, a média foi de seis (10 a dois. Encontramos nesses pacientes média de 2,39 na flexão frontal ativa (quatro a zero. Na força de flexão frontal a média foi de 4,09 com máxima de cinco e mínima de três. A média de pontos do escore da UCLA foi de 26,52. Noventa e cinco porcento dos pacientes ficaram satisfeitos com a cirurgia. CONCLUSÃO: A artroplastia parcial de ombro tipo CTA® tem resultados satisfatórios no tratamento da artropatia degenerativa do manguito rotador e apresenta baixa taxa de complicação.OBJECTIVE: To assess results of CTA® partial shoulder arthroplasty for treatment of degenerative arthropathy of the rotator cuff. METHODS: Between December 2006 and June 2009, 23 shoulders of 23 patients were submitted to CTA® type partial shoulder arthroplasty for treatment of arthropathy secondary to rotator cuff injury. Post-operative follow up time ranged from 6 to 35

  13. Degenerações periféricas da retina do olho míope X LASIK

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    Nassaralla Jr. João J.

    2004-01-01

    Full Text Available O objetivo deste artigo é apresentar as degenerações periféricas mais comuns na retina dos olhos míopes, discutindo aquelas que oferecem maiores riscos para o descolamento regmatogênico da retina, seu relacionamento com a cirurgia de LASIK e a indicação para o tratamento profilático.

  14. Estratégia saúde da família no tratamento de doenças crônico-degenerativas: avanços e desafios Estrategia de salud de la familia en el tratamiento de las enfermedades crónico-degenerativas: logros y retos Family health strategy in the treatment of chronic-degenerative diseases: achievements and challenges

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    Márcia Adriana Zavatini

    2010-12-01

    Full Text Available Estudo retrospectivo, exploratório, de natureza quantitativa realizado em uma Equipe de Saúde da Família (ESF no município de Maringá, Estado do Paraná, Brasil, com o objetivo de avaliar a efetividade da ESF no tratamento de doenças crônico-degenerativas. Foram utilizados dados do período de maio de 2006 a setembro de 2009, de 94 pacientes portadores de hipertensão arterial sistêmica e/ou diabetes mellitus, por meio da análise do sistema de acompanhamento de hipertensos e diabéticos e prontuários. Foi verificado um pequeno aumento no número de indivíduos com valores de pressão arterial (p = 0,773 e glicemia de jejum (p = 0,745 considerados adequados, no período analisado; apesar das mudanças na farmacoterapia destes pacientes e acompanhamento domiciliar. Conclui-se que apenas alterações na farmacoterapia prescrita são insuficientes para o controle adequado destas enfermidades, sendo necessário o desenvolvimento de intervenções da equipe de saúde, que promova a prática do autocuidado nos indivíduos e seus familiares.Estudio retrospectivo, exploratorio, cuantitativo desarollado en un Equipo de Salud de la Familia (ESF en la ciudad de Maringá, Paraná, Brasil, con lo objetivo de evaluar la eficacia de la ESF en el tratamiento de las enfermedades crónicas. Se utilizaron dados recogidos entre mayo de 2006 y septiembre de 2009, de 94 pacientes con hipertensión arterial y/o diabetes mellitus, mediante el análisis de los registros del sistema de control de hipertensos y diabéticos y registros. Se observó ligero incremento en el número de individuos con presión arterial (p = 0,773 y glucosa en sangre en ayunas (p = 0,745 considerados adecuados, en el periodo analizado; pesar de los cambios en la farmacoterapia y cuidados en el hogar. Se concluye que solamente cambios en la farmacoterapia no son suficientes para un adecuado control destas enfermedades, siendo necesario el desarrollo de intervenciones de la ESF, que

  15. Analgesia preemptiva com dipirona versus ibuprofeno na fotocoagulação a laser da retina

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    Artur Macaferri Del Santo

    2016-02-01

    Full Text Available RESUMO Objetivo: Comparar a efetividade da dipirona versus o ibuprofeno para a redução da dor na fotocoagulação da retina (FR. Método: Foi realizado um estudo controlado, duplo cego e randomizado englobando trinta e quatro pacientes com retinopatia diabética separados em dois grupos. Grupo A recebeu 1000mg de dipirona e o grupo B recebeu 600mg de ibuprofeno. A dor foi avaliada pela escala visual analógica. Resultado: A média do escore da dor nos grupos A e B foi de 5,2 ± 2.6 e 4,5 ± 1,4, respectivamente. Não houve diferença estatística entre os grupos (p=0,34. O mesmo foi observado quanto à analise entre dor leve, moderada e grave (p=0,09. Os grupos foram semelhantes quanto à idade e sexo. Conclusão: Os medicamentos foram equivalentes ou equipotentes em reduzir a dor ocular durante a fotocoagulação a laser da retina.

  16. Instrumentação interespinhosa na doença degenerativa da coluna lombar: medição da altura do disco no segmento instrumentado Instrumentación interespinosa en la enfermedad degenerativa de la columna lumbar: medición de la altura del disco en el segmento instrumentado Interspinous instrumentation in patients with degenerative lumbar spine disease: disc height measurement on instrumented segment

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    José Alberto de Castro Guimarães Consciência

    2009-09-01

    Full Text Available INTRODUÇÃO: na última década, a instrumentação interespinhosa vem sendo mais frequentemente utilizada. Apesar dos inúmeros artigos publicados em revistas internacionais de reconhecido mérito científico, são escassas as referências à modificação da altura do disco no segmento tratado, secundária àquela instrumentação. OBJECTIVO: quantificar uma eventual modificação da altura discal decorrente da aplicação de instrumentação interespinhosa (DIAM - Cousin-Biotech - Medtronic Sofamor Danek Inc©. MÉTODOS: o autor avalia um grupo de 20 pacientes com patologia degenerativa da coluna lombar e os seguintes critérios de inclusão: idade >40 e 6; Oswestry Disability Index (ODI >30; Zung Depression Rating Scale INTRODUCCIÓN: la instrumentación interespinosa tiene sido empleada con creciente frecuencia en la última década. Pero, apesar de las numerosas publicaciones científicas hechas en jornales científicos de reconocido mérito internacional, se han producido muy escasas referencias a una hipotética modificación de la altura discal dependiente de la técnica. OBJETIVO: cuantificar una eventual modificación de la altura discal inherente a la aplicación de instrumentación interespinosa. MÉTODOS: el autor hace una evaluación de un grupo de 20 pacientes con patología degenerativa de la columna lumbar, y diversos criterios de inclusión, a saber: edad >40 y 6; Oswestry Disability Index >30; Zung Depression Rating Scale INTRODUCTION: the use of interspinous instrumentation has been increasing in the last decade. However, in spite of the numerous papers seen in relevant scientific publications, there are very few references to an eventual disc height variation in the instrumented segment. OBJECTIVE: to certify eventual changes in disk height after interspinous instrumentation (DIAM - Cousin-Biotech - Medtronic Sofamor Danek Inc©. METHODS: the author evaluated 20 patients with degenerative lumbar disease and the following

  17. Use of chondroitin sulphate and glucosamine sulphate in degenerative changes in TMJ: a systematic review Utilização de sulfato de condroitina e sulfato de glicosamina nas alterações degenerativas da ATM: uma revisão sistematica

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    Eduardo Machado

    2012-08-01

    Full Text Available INTRODUCTION: Degenerative changes in Temporomandibular Joint (TMJ have increased in prevalence and severity over the years. Within this context, it's necessary to obtain safe and effective therapies for control and management of the patient in cases of osteoarthritis and osteoarthrosis of the TMJ. Therapeutic options range from intra-articular infiltration protocols, occlusal splints, pharmacological therapies and physiotherapy and educational measures. The alternative treatment with structure-modifying agents, like as chondroitin and glucosamine sulphates, showed promising results, and especially safety. Thus, through a systematic literature review, this study aimed to analyze and discuss effectiveness and safety of chondroitin and glucosamine in degenerative changes of the TMJ. METHODS: Survey in research bases MEDLINE, Cochrane, EMBASE, Pubmed, Lilacs and BBO, between the years of 1966 and January 2009, with focus in randomized clinical trial (RCTs and quasi-randomized clinical trials, systematic reviews and meta-analysis. RESULTS: After application of the inclusion criteria 2 articles were selected, both randomized controlled double-blind clinical trials, which evaluated the effectiveness of chondroitin and glucosamine in degenerative changes of the TMJ. CONCLUSIONS: There is the necessity of further RCT, with representative samples and long follow-up time, to obtainment more precise cause-effect relationships and to achieve an effective and objective protocol involving chondroitin and glucosamine in cases of degenerative changes of the TMJ.INTRODUÇÃO: as alterações degenerativas da Articulação Temporomandibular (ATM têm aumentado em prevalência e em severidade ao longo dos anos. Dentro desse contexto, surge a necessidade de se obter terapêuticas efetivas e seguras para o controle e o manejo do paciente em situações de osteoartrite e osteoartrose da ATM. As opções terapêuticas variam desde protocolos de infiltra

  18. Avaliação da autofluorescência do fundo de olho nas distrofias de retina com o aparelho Heidelberg Retina Angiograph2 Evaluation of fundus autofluorescence in hereditary retinal diseases using Heidelberg Retina Angiograph2

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    Monique Côco

    2007-10-01

    Full Text Available OBJETIVOS: Definir características do exame de autofluorescência, verificando sua utilidade no diagnóstico e acompanhamento de distrofias retinianas. MÉTODOS: Participaram do estudo, 28 pacientes, adultos, divididos igualmente em quatro grupos com diagnósticos de doença de Stargardt, distrofia de Cones, retinose pigmentar e voluntários saudáveis para estabelecimento do padrão de normalidade. Em média foram obtidas nove imagens com o filtro para angiofluoresceinografia para a formação da imagem autofluorescente no Heidelberg Retina Angiograph2. As imagens de cada grupo de pacientes foram analisadas para verificar características comuns. RESULTADOS: As imagens fundoscópicas autofluorescentes dos voluntários do grupo controle mostraram área foveal hipoautofluorescente em relação à retina do pólo posterior. As imagens dos portadores de doença de Stargardt, em geral, apresentaram lesão hipoautofluorescente, correspondendo à área macular. As principais alterações da autofluorescência em pacientes com distrofia de cones foram hipoautofluorescência macular com halo hiperautofluorescente. Nos portadores de retinose pigmentar, foram encontrados pigmentos periféricos causando hipoautofluorescência. Na região macular, hipoautofluorescência ou apenas desorganização do pigmento. CONCLUSÃO: O estudo mostrou a existência de padrões de autofluorescência de fundo nas distrofias de retina que permitem o diagnóstico e melhor interpretação da fisiopatogenia destas doenças.PURPOSE: To define characteristics of the fundus autofluorescence examination, verifying usefulness in the diagnosis and care of hereditary retinal diseases. METHODS: 28 patients, adults, divided equally into four groups with diagnoses of Stargardt macular dystrophy, cone dystrophy, retinitis pigmentosa and healthy volunteers for the establishment of the normality pattern. An average of nine images with the filter for fluorescein angiography was obtained

  19. Avaliação do tratamento da discopatia degenerativa cervical pela artrodese via anterior utilizando placas associadas a cages ou cages em peek isoladamente Evaluación del tratamiento de la enfermedad degenerativa del disco cervical por la artrodesis anterior utilizando placas asociadas con jaulas o jaulas en peec, aisladamente Evaluation of cervical degenerative disc disease treatment by anterior arthrodesis using plates associated with cages or cages in peek alone

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    André Rafael Hübner

    2011-01-01

    Full Text Available OBJETIVOS: Avaliar comparativamente o tratamento da discopatia degenerativa cervical por discectomia e artrodese cervical via anterior utilizando placas associadas a cages ou cages em PEEK isoladamente. MÉTODOS: Foi realizado um estudo retrospectivo comparativo entre dois grupos de pacientes operados pela técnica de discectomia e artrodese cervical via anterior. Foram selecionados aleatoriamente 70 pacientes, 35 operados com o método de fixação com placas associadas a cages - denominado Grupo I - e 35 com o cage em PEEK isoladamente - Grupo II. Realizou-se anamnese, exame físico, escores de dor (escala visual e analógica da dor e função (critérios de Odom's, SF-36, Indice de incapacidade do pescoço o pré e pós-operatório e exames de imagem. RESULTADOS: Houve predominância de pacientes do sexo feminino em ambos os grupos, com média de idade de 55 anos no Grupo I e 47 no Grupo II. Ambos os grupos apresentaram distribuição semelhante quanto ao número de níveis operados, assim como nas complicações encontradas e escores de dor, cervicalgia e SF36 no pré e pós-operatório. Houve 97.1% de fusão com 94.3% de bons resultados no Grupo I e 100% de fusão, com 97 % de bons resultados no Grupo II. CONCLUSÕES: O estudo comparativo da utilização de placas com cages e cages em PEEK isoladamente apresentou resultados semelhantes e satisfatórios para os grupos estudados, não se constatando superioridade ou inferioridade de um método com relação ao outro.OBJETIVOS: Evaluar comparativamente el tratamiento de la enfermedad degenerativa del disco cervical por discectomía y artrodesis cervical vía anterior, utilizando placas asociadas con el uso de jaulas o estas en PEEK [Poliéster-Éter-Éter-Cetona], aisladamente. MÉTODOS: fue realizado un estudio retrospectivo comparativo de dos grupos de pacientes tratados con la técnica de discectomía y artrodesis cervical vía anterior. Se seleccionaron al azar 70 pacientes, 35 operados

  20. Vitrectomy with and without scleral buckling for retinal detachment Vitrectomia com e sem "scleral buckling" para descolamento da retina

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    Rubens Camargo Siqueira

    2007-03-01

    Full Text Available PURPOSE: To compare the surgical results of vitrectomy with and without scleral buckling for rhegmatogenous retinal detachment (RD. METHODS: Fifty-one patients with rhegmatogenous retinal detachment with proliferative vitreoretinopathy (PVR at different stages were submitted to pars plana vitrectomy as the primary surgery, 23 patients (45.09% with scleral buckle (group I and 28 (54.90% without scleral buckle (group II. Visual acuity, anterior segment complications, intraocular pressure, strabismus and retina reattachment rate were evaluated in both groups. RESULTS: The anatomical success and postoperative complications were similar in both groups. Retinal reattachment was achieved in 20 of 23 eyes (87% of group I and in 24 of 28 eyes (85.7% of group II after the initial surgery (p=1.000. Elevated intraocular pressure was noted in 2 eyes (8.7% of group I and 1 eye (3.6% of group II (p=0.583. Corneal abnormalities were seen in 3 eyes (13% of group I and 2 eyes (7.19% of the group II (p=0.647. Visual acuity improved from a preoperative median of 20/200 to a median of 20/100 in group 1 and from 20/400 to 20/100 in group 2; the difference between the two groups was statistically significant (pOBJETIVOS: Comparar os resultados cirúrgicos da vitrectomia com e sem "buckle" escleral para descolamento da retina regmatogênico (DR. MÉTODOS: Cinqüenta e um pacientes com descolamento da retina regmatogênico com proliferação vitreorretiniana (PVR em diferentes estádios foram submetidos a vitrectomia pars plana como cirurgia primária; 23 pacientes (45,09% com buckle escleral (grupo 1 e 28 pacientes (54,90% sem "buckle" escleral (grupo 2. Acuidade visual, complicações do segmento anterior, pressão intra-ocular, estrabismo e razão do redescolamento da retina foram avaliados em ambos os grupos. RESULTADOS: O sucesso anatômico e complicações pós-operatórias foram semelhantes em ambos os grupos. A reaplicação da retina foi obtida em 20 dos 23

  1. Sulfato de condroitina e hialuronato de sódio no tratamento da doença articular degenerativa em cães: estudo histológico da cartilagem articular e membrana sinovial Chondroitin sulfate and sodium hyaluronate in the treatment of the degenerative joint disease in dogs: histological features of articular cartilage and synovium

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    E.G. Melo

    2008-02-01

    Full Text Available Quinze cães, sem raça definida, de ambos os sexos, de peso entre 18 e 25kg, foram submetidos à secção artroscópica do ligamento cruzado cranial (LCCr para indução da doença articular degenerativa (DAD. Após três semanas de instabilidade articular, o LCCr foi substituído pela fáscia lata segundo a técnica de Schwalder (1989 e os animais foram distribuídos em três grupos de cinco. Os animais do grupo I, controle, não receberam tratamento medicamentoso; os do grupo II, 24mg/animal de sulfato de condroitina, por via IM, de cinco em cinco dias, totalizando seis aplicações; e os do grupo III foram tratados com hialuronato de sódio na dose de 20mg/animal, por via IV, de cinco em cinco dias num total de três administrações. Ao final de 90 dias, os animais foram eutanasiados e procedeu-se à colheita e ao processamento histológico da membrana sinovial e da cartilagem articular para avaliações morfológica e morfométrica. No grupo I foram observadas alterações degenerativas de DAD mais acentuadas que nos demais grupos, como redução do número de condrócitos, presença de pânus, fibrilações, fissuras, erosões e irregularidades na superfície articular. No grupo II observou-se elevação do número de condrócitos com aumento da atividade de síntese da matriz e redução das lesões na superfície da cartilagem. No grupo III houve aumento do número de condrócitos que eram, muitas vezes, morfologicamente inviáveis. Todos os grupos apresentaram proliferação da membrana sinovial e presença de infiltrado linfoplasmocitário na subíntima e na perivascular. Nos grupos I e III, a proliferação da membrana sinovial era exuberante com formação de pânus, presença de sinoviócitos achatados ou ausência de sinóvia com tecido de granulação. Os resultados sugerem que o sulfato de condroitina estimulou a cartilagem articular, diminuindo ou retardando as alterações da DAD e o hialuronato de sódio não interferiu no

  2. Angiogênese e doenças da retina Angiogenesis and retinal diseases

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    Francisco Max Damico

    2007-06-01

    Full Text Available Angiogênese é o processo de formação de vasos sangüíneos a partir de vasos preexistentes, que ocorre em condições fisiológicas e patológicas. É fenômeno complexo no qual participam inúmeras moléculas que estimulam e inibem a formação dos neovasos. O aumento da permeabilidade vascular e a neovascularização sub-retiniana são as causas da perda visual nas doenças proliferativas da retina, como a degeneração macular relacionada à idade e a retinopatia diabética, e o fator de crescimento do endotélio vascular ("vascular endothelial growth factor", VEGF desempenha um papel muito importante nesse processo. Existem quatro isoformas da molécula de VEGF biologicamente ativas em seres humanos, das quais o VEGF165 é a isoforma predominante no olho humano, e existem evidências de que seja a isoforma responsável pela neovascularização patogênica no olho. Além de ser potente mitógeno de células endoteliais, o VEGF aumenta a permeabilidade vascular, inibe a apoptose das células endoteliais e promove migração de precursores de células endoteliais. O VEGF não é a única molécula cuja expressão está aumentada na angiogênese patológica. O fator de crescimento de fibroblasto ("basic fibroblast growth factor", bFGF, as angiopoetinas, o fator derivado do epitélio pigmentado ("pigment epithelium-derived factor", PEDF e os fatores de adesão relacionados à matriz extracelular também exercem papel importante no balanço entre fatores pró- e antiangiogênicos. Todo o conhecimento adquirido sobre o mecanismo da angiogênese ocular patológica tem possibilitado o desenvolvimento de vários inibidores desse processo. Atualmente existem dois anticorpos anti-VEGF para uso intravítreo e outras abordagens terapêuticas do bloqueio da angiogênese ocular estão em fase de desenvolvimento. As novas drogas deverão ser armas poderosas no tratamento das principais causas de cegueira legal irreversível em indivíduos com mais de 65

  3. Oclusão de ramo venoso da retina associado ao uso de infliximabe: relato de caso

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    Bruno Diniz

    2011-06-01

    Full Text Available Descrevemos o caso de uma paciente, de 53 anos, com quadro de oclusão de ramo venoso da retina após receber seis infusões de infliximabe (3 mg/kg/dose, para tratamento de artrite reumatóide. A investigação clínica e laboratorial sobre distúrbios de coagulação, cardiopatias e sinais de hipertensão arterial crônica foi negativa. A relação temporal do uso de infliximabe e o desenvolvimento do quadro de oclusão de ramo pode indicar um possível efeito adverso da medicação.

  4. Enfermedad valvular degenerativa canina: reporte de caso

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    Carmenza Janneth Benavides Melo

    2014-07-01

    Full Text Available En caninos, la enfermedad valvular degenerativa o endocardiosis es la patología cardiovascular con mayor prevalencia. Se caracteriza por regurgitación de la sangre hacia las aurículas, con disminución del gasto cardiaco, lo que lleva a sobrecarga de volumen con hipertrofia excéntrica e insuficiencia cardiaca congestiva. Este reporte tiene como objetivo describir los hallazgos clínicos y de necropsia de un canino, sugestivos de una endocardiosis valvular. El paciente ingresó por consulta externa a la Clínica Veterinaria Carlos Martínez Hoyos, de la Universidad de Nariño (Pasto, Colombia. Su propietario lo reportó enfermo desde hacía dos meses, con signos de enfermedad respiratoria, pérdida de peso y decaimiento. En el examen clínico se encontraron membranas mucosas muy pálidas, disnea inspiratoria, estertores, desdoblamiento de S2, soplo de regurgitación mesosistólico grado 4 y dilatación abdominal con signo de choque de onda positivo. En la necropsia se evidenció abundante cantidad de material de aspecto acuoso traslúcido en cavidad abdominal, torácica y pericárdica, corazón severamente aumentado de tamaño, redondeado, con engrosamiento de válvulas atrioventriculares, hígado con moderada disminución de tamaño y evidencia de lobulillación, riñones severamente disminuidos de tamaño y pálidos de superficie irregular con presencia de múltiples áreas quísticas en región corticomedular. Se tomaron muestras de estos tejidos y se fijaron en formol bufferado al 10 %, para después ser procesadas para análisis histopatólogico en el Laboratorio de Patología de la Universidad de Nariño, mediante la técnica de hematoxilina y eosina de rutina. De esta manera se diagnostica como enfermedad valvular degenerativa.

  5. Chondroprotectant therapy in rats with degenerative joint disease experimentally transected cranial cruciateReprodução experimental da doença articular degenerativa, pelo método cirúrgico associado à terapia condroprotetora, em ratos

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    Marcos Marini Melo

    2013-06-01

    Full Text Available Osteoarthritis (OA is the most common joint disease in both humans and animals, and it results in movement restriction and pain at the affected area. This disorder affects more than 25% of people over 60 years of age, and it is considered universal for 70-year-old people. OA is estimated to affect over 20% of the canine population from the United States of America. The present study aimed to evaluate the treatment of rats that were surgically induced to OA using two different drug therapies, one with pentosan polysulfate, one with betamethasone, and one with chondroitin sulfate/ glucosamine. In order to produce joint disease, the cranial cruciate ligament was surgically transected. Animals were kept and treated for eight days after surgery and were assessed via both radiographies and tomographies taken before surgery and eight weeks later. All animals were euthanized having both macroscopic and microscopic analysis performed to evaluate the disorder progression and therapeutic action. Macroscopic analysis showed lesion in the knees subjected to OA induction. The untreated animals presented major lesions whereas the treated ones presented mild to moderate lesions. In conclusion, pentosan polysulfate is recommendable for the treatment of iatrogenic joint lesions in rats since the other treatments showed no significant difference. A osteoartrite (OA é a doença articular mais comum em humanos e animais, o que ocasiona restrição de movimentos e dor, na região acometida. Tal enfermidade afeta mais de 25% dos humanos acima de 60 anos e, aos 70 anos, ela é considerada universal. Estima-se que nos Estados Unidos da América, 20% ou mais da população canina é acometida pela OA. O presente estudo tem como finalidade avaliar a terapia medicamentosa (polisulfato de pentosano, betametasona e sulfato de condroitina/glucosamina, em um modelo experimental de OA cirurgicamente induzido, em ratos. A doença articular foi promovida pela transecção cir

  6. Oclusão da artéria central da retina em paciente com poliangeíte microscópica

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    Cláudia Gallicchio Domingues

    2015-12-01

    Full Text Available RESUMO A poliangeíte microscópica é uma vasculite necrotizante sistêmica que acomete arteríolas, capilares e vênulas, mas também pode atingir pequenas e médias artérias. É considerada uma doença rara, idiopática e autoimune. Diversas anormalidades oculares e sistêmicas estão associadas às oclusões arteriais retinianas. Dentre as doenças vasculares do colágeno, a literatura cita como possíveis causas de obstrução das artérias retinianas o lúpus eritematoso sistêmico, a poliarterite nodosa, a arterite de células gigantes, a granulomatose de Wegener e a granulomatose linfóide de Liebow. Até o presente momento, não se encontrou na literatura relatos da associação de casos de oclusão arterial retinana associados à PAM. Os autores relatam o caso de um paciente com poliangeíte microscópica que apresentou comprometimento renal importante e oclusão da artéria central da retina unilateral. Atenta-se para a inclusão de pesquisa da PAM, através do p-ANCA, na avaliação de possível origem sistêmica em pacientes acometidos por oclusão arterial retiniana.

  7. Descompressão neural isolada ou associada à fusão póstero-lateral nas afecções degenerativas lombossacras: avaliação da qualidade de vida e incapacidade funcional pós-operatória Descompresión neural aislada o combinada con la fusión posterolateral en las enfermedades degenerativas lumbosacras: evaluación de la calidad de vida e incapacidad funcional después de la operación Neural decompression alone or combined with posterolateral fusion in lumbosacral degenerative diseases: assessment of postoperative quality of life and functional disability

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    Alberto Ofenhejm Gotfryd

    2012-01-01

    Full Text Available OBJETIVO: Comparar a qualidade de vida, a dor e a satisfação pessoal de pacientes submetidos à descompressão neural lombar isolada àqueles que tiveram a fusão póstero-lateral associada. MÉTODOS: Participaram do estudo 44 indivíduos com diagnóstico de hérnia de disco e/ou estenose degenerativa central ou foraminal da coluna lombossacra tratados cirurgicamente. Os pacientes foram divididos em 2 grupos: "descompressão" (D e "descompressão e fusão" (DF. O critério utilizado para definir a necessidade da artrodese foi a presença de deformidades ou instabilidade segmentar, mensurada através de radiografias simples e dinâmicas. Os pacientes preencheram questionários referentes ao acompanhamento pós-operatório (uso de medicamentos analgésicos e satisfação com o tratamento e escala analógica visual de dor lombar e ciática. Além disto, foram aplicados os questionários Oswestry e SF-36 para avaliação da qualidade de vida. RESULTADOS: Foram encontrados excelentes resultados no questionário Oswestry, bons níveis para os domínios "Dor" e "Capacidade Funcional" do SF-36, além de baixa intensidade de dor lombar e ciática em ambos os grupos analisados, não havendo diferenças estatisticamente significativas entre eles. CONCLUSÕES: Não encontramos diferenças em relação à qualidade de vida, à dor e à satisfação pessoal em pacientes submetidos à descompressão neural lombar isolada àqueles que tiveram a fusão associada, utilizando como critério indicativo para artrodese a presença de deformidades e/ou instabilidade segmentar.OBJETIVO: Comparar la calidad de vida, el dolor y la satisfacción personal de los pacientes sometidos a la descompresión neural aislada con aquellos que tuvieron la fusión posterolateral asociadas. MÉTODOS: El estudio reclutó a 44 pacientes con hernias discales y/o estenosis degenerativa central o foraminal de la columna lumbosacra, tratados quirúrgicamente. Los pacientes fueron divididos

  8. Tratamento da necrose aguda de retina: revisão sistemática Treatment of acute retinal necrosis: systematic review

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    Moysés Eduardo Zajdenweber

    2005-08-01

    Full Text Available OBJETIVO: O objetivo deste estudo foi pela realização de revisão sistemática, determinar o melhor tratamento para a necrose aguda de retina. MÉTODOS: Seguindo a orientação metodológica da Colaboração Cochrane e de seu subgrupo editorial "Eye and Vision Group", o autor, por meio de mecanismos de busca, selecionou trabalhos sobre o tratamento da necrose aguda de retina. RESULTADO: Foram selecionadas 146 referências bibliográficas, sendo considerados como relevantes 13 estudos. Destes estudos 2 foram considerados como preenchendo os critérios de inclusão. O primeiro estudo aponta a possibilidade de o tratamento para necrose aguda de retina, com aciclovir endovenoso associado a corticóide sistêmico, proteger o olho contralateral de acometimento. Foram estudados 54 pacientes, 31 tratados e 23 não tratados, sendo observada incidência de doença no olho contralateral de 12,9% no grupo tratado e de 69,5% no grupo não tratado. O segundo estudo incluído mostra 19 olhos acometidos com necrose aguda de retina, sendo que 12 destes olhos foram submetidos à fotocoagulação com laser de argônio, com o objetivo de prevenir o descolamento de retina. Dos 12 olhos, 2 desenvolveram descolamento de retina (16,6% ao passo que, no grupo não tratado, composto por 7 olhos, 4 desenvolveram descolamento de retina (57,1%. CONCLUSÃO: O autor conclui que os dois tipos de intervenção propostos se mostraram eficazes, porém, como os estudos são metodologicamente fracos, torna-se necessária a realização de estudos clínicos randomizados para que se possa estabelecer o melhor tratamento para a necrose aguda de retina.PURPOSE: The purpose of this study was to identify, according to an sistematic review, the best treatment for acute retinal necrosis. METHODS: Following the methodologic guidance of the Cochrane Collaboration and its editorial subgroup "Eye and Vision Group", using search strategy for study identification, articles about the treatment

  9. Avaliação das alterações fundoscópicas na miopia degenerativa Fundus changes evaluation in degenerative myopia

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    Oswaldo Ferreira Moura Brasil

    2006-04-01

    Full Text Available OBJETIVO: Avaliar a presença de alterações fundoscópicas em pacientes portadores de miopia degenerativa. MÉTODOS: Quarenta pacientes com erro refrativo de pelo menos -6,00 dioptrias foram selecionados para exame oftalmológico, complementado por retinografia do pólo posterior e ecobiometria. RESULTADOS: Foram estudados 57 olhos de 37 pacientes com erro refrativo de -6,25 a -28,50 dioptrias, com média de -14,05, e comprimento axial de 26,06 a 32,86 mm, com média de 28,01. Encontramos crescente temporal em 36,5% e circunferencial em 21% dos olhos. Vasos da coróide foram visualizados em 35% dos olhos. As alterações do pólo posterior foram as seguintes: estafiloma posterior em 10,5%, mancha de Fuchs em 3,5% e "lacquer cracks" em 1,5%. O exame da periferia retiniana evidenciou atrofia corio-retiniana tipo pavimentosa em 17,5%, branco sem pressão em 10,5%, degeneração "lattice" em 5%, ruptura retiniana em 3,5% e retinosquise em 1,5% dos olhos examinados. CONCLUSÕES: Alterações fundoscópicas que levam à baixa visual são freqüentes em pacientes com miopia degenerativa. O exame da periferia retiniana é muito importante nestes pacientes devido ao risco aumentado de descolamento de retina.PURPOSE: To evaluate the presence of fundus changes in degenerative myopia. METHODS: Forty patients with refractive error of at least -6.00 diopters were selected for ophthalmologic examination followed by posterior pole photograph and echobiometry. RESULTS: We studied 57 eyes of 37 patients with refractive error ranging from -6.25 to -28.50 diopters, with mean -14.05, and axial length ranging from 26.06 to 32.86 mm, with mean 28.01. We found a temporal crescent in 36.5% and a peripapillary one in 20% of the eyes. Choroidal vessels were seen in 35% of the eyes. Posterior pole changes were as follow: posterior staphyloma in 10.5%, Fuchs' spots in 3.5% and lacquer cracks in 1.5%. Peripheral retinal examination revealed paving stone chorioretinal

  10. Desmopatia degenerativa em equinos: métodos de diagnóstico em animais vivos

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    S.V. Schwarzbach

    2010-08-01

    Full Text Available A desmopatia degenerativa (DD possui caráter sistêmico e manifesta-se por acúmulos de proteoglicanos (PG na matriz extracelular (MEC de tecidos que contenham colágeno. Este estudo teve o objetivo de diagnosticar equinos suspeitos de serem acometidos por DD, em um plantel de animais de raça nacional, segundo o ângulo da articulação metatarsofalangiana (AMF e a presença de acúmulos de PG em amostras de ligamento da nuca (LN. Analisaram-se 123 equinos clinicamente sadios e somente três (2,7% deles, segundo o ângulo AMF < 146(0, foram considerados suspeitos. Não houve diferença significativa entre os grupos. Quinze éguas foram submetidas ao exame do ângulo da AMF e à biópsia do LN, das quais sete (47,7% foram consideradas suspeitas, segundo ângulo da AMF, enquanto seis (40% apresentaram acúmulos de PG. Foram encontrados acúmulos de PG em três (20% éguas não suspeitas. Um animal suspeito não apresentou alterações histológicas compatíveis de DD.

  11. Análise da camada de fibras nervosas da retina em portadores de enxaqueca com aura Retinal nerve fiber layer measurements in patients with migraine with aura

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    Felipe Andrade Medeiros

    2001-10-01

    Full Text Available Objetivo: Avaliar as possíveis alterações na camada de fibras nervosas da retina (CFNR em pacientes com enxaqueca com aura, detectada por meio da polarimetria de varredura a laser. Métodos: Vinte pacientes com enxaqueca com aura e vinte indivíduos normais foram estudados. Os critérios de inclusão para os dois grupos compreenderam: idade de pelo menos 18 anos; ausência de história de doenças oculares, exceto erro refracional ou estrabismo; e ausência de história familiar de hipertensão ocular ou glaucoma. Foram excluídos pacientes com erro refracional maior que 5 DE e/ou 2 DC; acuidade visual corrigida menor que 20/40; pressão intra-ocular maior que 21 mmHg; discos ópticos anômalos ou com escavação maior que 0,5 ou assimetria de escavação maior que 0,2; ou com presença de doenças retinianas concomitantes. Os pacientes foram submetidos a exame de campo visual (Humphrey 30-2 e análise da CFNR com a polarimetria a laser (GDx - Nerve Fiber Analyzer. Um olho de cada paciente foi randomizado para análise estatística. Resultados: Nenhum dos pacientes do grupo controle apresentou defeitos de campo visual. Nove olhos (45% dos pacientes com enxaqueca tiveram anormalidades de campo visual além de 95% do intervalo de confiança do normal, como indicado pelos índices MD, CPSD ou GHT. Os valores de retardo no setor superior da CFNR dos pacientes com enxaqueca foram significativamente menor que no grupo controle (p=0,005. Não houve diferença significativa entre os valores de retardo dos dois grupos nas medidas globais e nos setores inferior, nasal e temporal. Conclusão: As medidas de retardo obtidas com a polarimetria a laser foram significativamente menores na porção superior da CFNR dos pacientes com enxaqueca com aura, sugerindo possível dano isquêmico às fibras nervosas, relacionadas à enxaqueca.Purpose: To evaluate the possible alterations of the retinal nerve fiber layer (RNFL, as detected by scanning laser polarimetry

  12. Retinal peripheral changes after LASIK Alterações da retina periférica após LASIK

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    João Jorge Nassaralla Junior

    2008-06-01

    26,5 anos, foram submetidos ao exame completo do pólo posterior, antes e após 1 semana, 1, 3 e 12 meses do LASIK bilateral simultâneo para a correção de miopia. A média do equivalente esférico foi 7,75D (variando entre -1,00 a 17,25D. Tratamento profilático foi realizado em lesões predisponentes a complicações retinianas, com fotocoagulação a laser, antes do LASIK. RESULTADOS: Antes da cirurgia, as características oftalmoscópicas foram: 86 olhos (43% não apresentavam nenhuma anormalidade periférica; 49 olhos (24,5% apresentavam degeneração em paliçada; 18 olhos (9%, branco sem pressão; 5 olhos (2,5%, branco com pressão; 33 (16,5%, degeneração orocoroidal; 6 (3%, degeneração pavimentosa; 45 (22,5%, descolamento de vítreo posterior; 20 (10%, tração vítreo-retiniana; e 12 (6%, buracos retinianos. Comparando a incidência de características oftalmoscópicas antes e um ano após a cirurgia, não houve diferença estatisticamente significativa (p>0.05. CONCLUSÃO: Embora condições patológicas da retina tenham sido descritas como complicações após o LASIK, nossos dados não revelaram uma relação de causa-efeito entre o procedimento para correção do erro refrativo e complicações retinianas. As alterações retinianas encontradas após o LASIK, nesta série de pacientes, parecem refletir a predisposição natural dos míopes. Paciente e cirurgião devem estar atentos aos riscos de complicações relacionadas aos olhos míopes, que persistem mesmo após o LASIK.

  13. The retina

    DEFF Research Database (Denmark)

    van Reyk, David M; Gillies, Mark C; Davies, Michael Jonathan

    2003-01-01

    A prominent and early feature of the retinopathy of diabetes mellitus is a diffuse increase in vascular permeability. As the disease develops, the development of frank macular oedema may result in vision loss. That reactive oxygen species production is likely to be elevated in the retina, and tha...

  14. Análise quantitativa da camada de fibras nervosas da retina de cães normais e glaucomatosos através da polarimetria a laser

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    Ana Lucia Braga Martins

    2003-01-01

    Full Text Available As lesões glaucomatosas são progressivas e irreversíveis. Estudos sobre o aparecimento e comportamento desta enfermidade vêm sendo discutidos na oftalmologia em geral. O diagnóstico precoce é de extrema importância para o tratamento e estabilização da mesma. A análise da espessura da camada de fibras nervosas retinianas ''in vivo'' foi proposta na oftalmologia humana, para estabelecer as alterações produzidas pelo glaucoma, e tem demonstrado que tais alterações podem ser detectadas até seis anos antes de alterações de campo visual e aumento de pressão intraocular. Entretanto, na Medicina Veterinária, estes dados carecem de estudo e discussão. Neste experimento foram utilizados dois grupos de cães, com olhos normais e olhos glaucomatosos, que foram submetidos à análise das fibras nervosas retinianas através do Analisador de Fibras Nervosas GDx. Os resultados estatísticos demonstraram que a camada de fibras nervosas dos olhos dos cães glaucomatosos estava mais delgada (p < 0,05 quando comparados aos olhos de cães normais, confirmando a perda de axônios das células ganglionares em olhos de cães com glaucoma.

  15. La miopía degenerativa desde una perspectiva social

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    Suzel Ivón Lapido Polanco

    Full Text Available La miopía degenerativa y sus consecuencias para la visión en individuos jóvenes es uno de los problemas de salud a los que se enfrenta el profesional de la oftalmología. Se redactó un ensayo en el que se valoraron los principios de la bioética como paradigmas para el oftalmólogo actual, aplicados a la enfermedad. Se tuvo en cuenta la influencia de la sociedad y el desarrollo científico-técnico en los pacientes que presentan esta afección y repercusión de la miopía en la formación de la personalidad y en sus relaciones con la familia y la sociedad.

  16. Doplervelocimetria das artérias oftálmica e central da retina em gestantes normais Dopplervelocimetry of ophthalmic and central retinal arteries in normal pregnancies

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    Angélica Lemos Debs Diniz

    2005-04-01

    Full Text Available OBJETIVOS: avaliar os padrões dos índices doplervelocimétricos das artérias oftálmica e central da retina durante o segundo e terceiro trimestres da gestação normal e comparar os valores obtidos do olho direito e esquerdo das gestantes. MÉTODOS: estudo transversal no qual se avaliaram seis índices doplervelocimétricos das artérias central da retina e oftálmica em 51 gestantes normais, com idades gestacionais entre a 20ª e a 38ª semana. As variáveis analisadas foram os índices de resistência e pulsatilidade (IR, IP, os picos de velocidade sistólica e diastólica (PVS, PVD e a razão entre picos de velocidade (RPV. A análise dos índices doplervelocimétricos dos olhos direito e esquerdo foi realizada utilizando-se a mediana dos valores. Para a comparação dos valores dos índices entre os dois olhos das gestantes, utilizou-se o teste t de Student para dados pareados. A associação entre a idade gestacional e os índices foi testada empregando-se o coeficiente de correlação linear de Pearson. Adotou-se o nível de significância de 5% para os testes estatísticos. RESULTADOS: a mediana dos índices doplervelocimétricos das artérias oftálmica e central da retina foram, respectivamente: IP=1,83; IR=0,78; PVS=34,20; PVD=6,80; RPV=0,48 e IP=1,34; IR=0,70; PVS=7,40; PVD=2,10. Não houve diferenças na análise comparativa dos índices doplervelocimétricos entre os olhos direito e esquerdo das gestantes normais. O coeficiente de correlação linear entre a idade gestacional e os índices de ambas as artérias não mostrou diferença significante durante a gestação normal. CONCLUSÃO: é factível a análise unilateral dos índices doplervelocimétricos das artérias oftálmica e central da retina no estudo de doenças maternas sistêmicas. Não há mudança significativa dos índices doplervelocimétricos das artérias oftálmica e central da retina ao longo da gestação normal entre a 20ª e a 38ª semana.PURPOSE: to

  17. Alteração da camada de fibras nervosas da retina em usuários crônicos de cloroquina Retinal nerve fiber layer alteration in chronic users of chloroquine

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    Daniela de Almeida Lyra Antunes

    2005-04-01

    Full Text Available OBJETIVOS: Avaliar a camada de fibras nervosas da retina (CFN por meio da polarimetria a laser, em pacientes em uso crônico de cloroquina. MÉTODOS: Foram estudados 44 olhos de 22 pacientes em uso de cloroquina por doenças reumatológicas, por pelo menos um ano. Como controle, foram incluídos vinte indivíduos sem uso de cloroquina com idade, gênero e raça similares. Foram excluídos os pacientes que apresentavam história familiar de hipertensão ocular ou glaucoma. Ambos os olhos foram submetidos à análise da camada de fibras nervosas da retina, com o aparelho GDx® Nerve Fiber Analyser, pelo mesmo examinador. RESULTADOS: Nos usuários crônicos de cloroquina, verificou-se alteração em mais de dois parâmetros do GDx em 28 olhos (63,6%. Ocorreu também alteração no gráfico "Deviation from normal" com perda de fibras nervosas em 11 olhos (25%. Quando comparado com o grupo controle, os parâmetros que demonstraram diferença estatisticamente significante foram: Superior Ratio, Inferior Ratio, Superior Nasal, Elipse Modulation, The Number, Superior Average e Superior Integral. Houve também associação estatisticamente significante entre o tempo de uso de cloroquina e perda da CFN. CONCLUSÕES: Comprovou-se a associação entre o uso crônico da cloroquina e a alteração da CFN detectada pelo GDx. Desta forma, esses resultados podem contribuir para o diagnóstico precoce da perda de fibras nervosas na retinopatia por cloroquina.PURPOSES: To evaluate the retina nerve fiber layer by laser polarimetry in patients in chronic use of chloroquine. METHODS: Forty-four eyes of twenty-two patients were studied. These were in use of chloroquine due to rheumatic diseases during at least one year. As a control group, twenty patients without use of chloroquine with similar characteristics (age, gender and race were included. Patients who had a family history of ocular hypertension or glaucoma were not included in this group. Both eyes were

  18. Análise da camada de fibras nervosas da retina em usuários crônicos do tabaco e álcool Analysis of retinal nerve fiber layer in chronic tobacco and alcohol users

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    Rita de Cássia Ramos de Lima

    2006-06-01

    Full Text Available OBJETIVOS: Avaliar a camada de fibras nervosas (CFN da retina, através da polarimetria a laser (GDx, em usuários crônicos do tabaco e álcool. MÉTODOS: Foram estudados 46 olhos de 23 indivíduos alcoólatras e tabagistas crônicos triados do Ambulatório de Oftalmologia da Fundação Altino Ventura (grupo estudo. Como grupo controle foram incluídos 32 olhos de 16 voluntários não-usuários do álcool e tabaco, com idade, gênero e raça similares, também triados da Fundação Altino Ventura. Ambos os olhos de todos os indivíduos foram submetidos à análise da camada de fibras nervosas da retina, com aparelho "GDx nerve fiber analyses" pelo mesmo examinador. RESULTADOS: No gráfico Deviation from normal, no grupo estudo ocorreu perda de fibras nervosas da retina em 43,4%, enquanto que no grupo controle houve perda apenas em 18,7%. Quanto aos parâmetros que analisam o GDx, quando comparados o grupo estudo com o grupo controle, observou-se diferença estatisticamente significante nos parâmetros: Ellipse modulation, Inferior ratio e Max modulation. CONCLUSÕES: Os dados comprovam a associação entre o uso crônico do tabaco e álcool e a alteração na camada de fibras nervosas da retina, podendo contribuir para o diagnóstico precoce desta neuropatia.PURPOSES: To evaluate the retinal nerve fiber layer using GDx in chronic alcohol and tobacco users. METHODS: Twenty-three chronic alcohol and tobacco users were studied (study group. As a control group, sixteen volunteers without use of alcohol and tobacco with similar characteristics (age, gender and race were included. Both eyes were tested for analysis of the retinal nerve fiber layer with GDx. RESULTS: There was alteration in the Deviation from normal graph with a loss of nerve fibers in 43.4% of patients in the study group. In the control group this alteration was observed in 14 eyes (18.7%. As regards the parameters that allow comparison between the study and control groups there was

  19. Avaliação da espessura da camada de fibras nervosas da retina e mácula em pacientes com ambliopia Thickness of the retinal nerve fiber layer, macular thickness, in patients with amblyopia

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    Juliana Mitre

    2010-02-01

    Full Text Available OBJETIVO: Avaliar a espessura da camada de fibras nervosas da retina em olhos amblíopes e comparar com olhos normais e certificar se há correlação com a redução da acuidade visual. Além disso, este estudo se propõe avaliar a eficácia e eficiência em uma série de casos do protótipo de um equipamento nacional de magnificação para leitura. MÉTODOS: Participaram deste estudo 30 pacientes na faixa etária entre 9 e 80 anos (17 do sexo masculino. Foi desenvolvido um aparelho portátil, patenteado pela Unifesp (PI#020050145260, com um sistema de captura de imagens acoplado a um monitor de 5,6 polegadas proporcionando um aumento de 15 x. Foram analisadas a eficácia da acuidade visual e a eficiência de leitura após a utilização do protótipo proposto. RESULTADOS: Seis pacientes (20% apresentaram AV 8M, 12 pacientes (40% apresentaram AV 6M, 7 pacientes (23,3% apresentaram 5 M, 5 pacientes (16,7% apresentaram 4M. A média de acuidade visual antes da utilização do SLP medida pela tabela LHNV-1 logMAR foi de 5,75M e após a utilização 100% dos pacientes atingiram a eficácia de AV J1. CONCLUSÃO: O protótipo do SLP mostrou-se um recurso alternativo no processo de inclusão social das pessoas com baixa visão com diferentes níveis de resíduo visual. Também pode proporcionar incentivo psicológico, permitir conforto, mobilidade e independência àqueles que necessitam de uma leitura mais prolongada e maior distância de trabalho.OBJECTIVE: To compare the thickness of the retinal nerve fiber layer (RNFLand the macular thickness of the amblyopic eye with those of the non-amblyopic eye in patients with unilateral amblyopia using optical coherence tomography (OCT. METHODS: OCT was performed for13 patients with unilateral amblyopia who had no neurologic disease. Nine male andfour female patients, whose ages ranged from 23 to 63 years, were enrolled in the study. The RNFL thickness average analysis program was used to evaluate mean

  20. Variação do fluxo sanguíneo da artéria central da retina durante as diferentes fases do ciclo menstrual ovulatório Central retinal artery blood flow variation during menstrual cycle

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    Luiz Carlos Viana

    2007-03-01

    Full Text Available OBJETIVO: avaliar a resistência vascular da artéria central da retina, por meio do fluxo Doppler, nas diferentes fases do ciclo menstrual ovulatório. MÉTODOS: estudo observacional, longitudinal e prospectivo com avaliação de 34 mulheres saudáveis, submetidas a estudo dopplerfluxométrico do fundo do olho para avaliação da resistência vascular da artéria central da retina nas posições sentada e deitada, durante quatro fases do ciclo menstrual: fase folicular inicial, fase folicular média, fase periovulatória e fase lútea média. A confirmação da ovulação no ciclo de estudo foi feita pela dosagem de progesterona sérica na fase lútea média. Foram avaliados os índices de pulsatilidade (IP e de resistência, e as velocidades máxima, mínima e média. RESULTADOS: a idade média foi de 29,7 anos. Não foram observadas diferenças entre os índices obtidos para ambos os olhos; assim, utilizamos as médias dos índices para realizar o cálculo estatístico. Quando comparadas às posições de realização do exame, detectou-se um IP maior na posição sentada; assim, as análises foram avaliadas em separado, respeitando-se a posição da paciente. O IP da artéria central da retina, avaliado com a paciente deitada, variou durante o ciclo menstrual, apresentando-se significativamente mais baixo nas fases folicular média (1,5±0,3 e periovulatória (1,5±0,3 quando comparadas às fases folicular precoce (1,7±0,4 e lútea média (1,7±0,4. Quando a avaliação foi feita com a paciente sentada não foram observadas diferenças para as diferentes fases do ciclo. CONCLUSÕES: num ciclo menstrual ovulatório ocorre diminuição da resistência vascular na artéria central da retina e posterior reversão do efeito, como demonstrado pelas variações do IP.PURPOSE: to evaluate the vascular blood flow of the central retinal arteries using dopplervelocimetry in the different phases of the ovulatory menstrual cycle. METHODS: we performed

  1. Alteraciones del polo posterior en la miopía degenerativa Alterations of the posterior pole in degenerative myopia patients

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    Suzel Ivón Lapido Polanco

    2012-12-01

    Full Text Available La miopía degenerativa constituye una de las causas fundamentales de pérdida de la visión. Esto está relacionado con las alteraciones del polo posterior, que afectan la retina neurosensorial, el epitelio pigmentario de la retina y las capas más internas de la coroides. Su curso lento y progresivo demanda una exploración integral, con seguimiento en el tiempo y constituye un reto para el oftalmólogo. Se realizó una revisión de artículos publicados e indexados en la base de datos de PubMed que se refirieran a las características clínicas del fondo de ojo en pacientes con miopía degenerativa, para describir las principales alteraciones del polo posterior del globo ocular en esta entidad. Se encontró entre las lesiones típicas de la alta miopía, al estafiloma posterior como un signo patognomónico de la enfermedad, asociado a la atrofia coriorretiniana en parches o difusa, así como las estrías de laca y las hemorragias maculares secundarias a ellas o provenientes de membranas neovasculares coroideas. La tomografía de coherencia óptica ha permitido un diagnóstico más preciso de otras lesiones maculares como la foveosquisis, el agujero macular y, más recientemente, la mácula en domo. Los cambios degenerativos del polo posterior parecen guardar relación unos con otros pero la patogenia no ha sido bien esclarecida a pesar de los avances tecnológicos.Degenerative myopia is one of the main causes of visual impairment. This is related to disorders in the posterior pole, affecting the neurosensorial retina, the retinal pigmented epithelium and the inner choroidal layers. The slow and progressive course of this condition demands comprehensive assessment and long follow-up, which is a challenging task for ophthalmologists. A review of the articles indexed in PubMed regarding the clinical characteristics of the fundus in patients with degenerative myopia was made to describe the main disorders of the posterior pole of the eyeball

  2. Reprodutibilidade do exame de medida da camada de fibras nervosas da retina por meio da polarimetria de varredura a laser Reproducibility of retinal nerve fiber layer measurement by scanning laser polarimetry

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    Fernanda Bon Duarte

    1999-10-01

    Full Text Available Objetivo: Analisar a reprodutibilidade das medidas da espessura da camada de fibras nervosas da retina intra e inter-observador. Material e Métodos: As medidas da camada de fibras nervosas foram realizadas em 26 olhos normais por três examinadores diferentes, os quais tomaram três imagens de cada olho. Com base nestas imagens foi executada a média das imagens pelo programa do aparelho. A cada examinador foi solicitado que escolhesse a melhor imagem para cada exame. Foram analisados os resultados obtidos com a melhor imagem, bem como os da média das imagens. Foi calculada a média da espessura da camada de fibras nervosas nas regiões superior, nasal, temporal e inferior e suas relações. Determinou-se a reprodutibilidade nestas circunstâncias tanto inter como intra-observador por meio de teste de análise de variância por postos de Friedman. Resultados: Na análise intra-observador houve ótima reprodutibilidade do exame. Para o examinador G (glaucomatólogo os valores de p foram os seguintes: região superior = 0,48; inferior = 0,89; temporal = 0,30 e nasal = 0,89. Para o examinador R (residente os valores de p foram os seguintes: região superior = 0,89; inferior = 0,24; temporal = 0,89 e nasal = 0,30 e para o examinador T (tecnóloga os valores de p foram os seguintes: região superior = 0,76; inferior = 0,70; temporal = 0,22 e nasal = 0,63. Na análise inter-observador, não foi observada diferença estatisticamente significante das variáveis isoladas considerando-se a média das imagens (p superior = 0,52; inferior = 0,37; temporal = 0,43 e nasal = 0,52. Considerando-se as relações entre as regiões temos que apenas a relação S/I mostrou diferença estatisticamente significante. As demais relações: S/T, S/N, I/T, I/N e T/N não mostraram diferença estatisticamente significante. Para a melhor imagem observou-se diferença estatisticamente significante entre os três examinadores para as variáveis superior/temporal (p = 0

  3. Retina-Inspired Filter.

    Science.gov (United States)

    Doutsi, Effrosyni; Fillatre, Lionel; Antonini, Marc; Gaulmin, Julien

    2018-07-01

    This paper introduces a novel filter, which is inspired by the human retina. The human retina consists of three different layers: the Outer Plexiform Layer (OPL), the inner plexiform layer, and the ganglionic layer. Our inspiration is the linear transform which takes place in the OPL and has been mathematically described by the neuroscientific model "virtual retina." This model is the cornerstone to derive the non-separable spatio-temporal OPL retina-inspired filter, briefly renamed retina-inspired filter, studied in this paper. This filter is connected to the dynamic behavior of the retina, which enables the retina to increase the sharpness of the visual stimulus during filtering before its transmission to the brain. We establish that this retina-inspired transform forms a group of spatio-temporal Weighted Difference of Gaussian (WDoG) filters when it is applied to a still image visible for a given time. We analyze the spatial frequency bandwidth of the retina-inspired filter with respect to time. It is shown that the WDoG spectrum varies from a lowpass filter to a bandpass filter. Therefore, while time increases, the retina-inspired filter enables to extract different kinds of information from the input image. Finally, we discuss the benefits of using the retina-inspired filter in image processing applications such as edge detection and compression.

  4. Correcção de escoliose lombar degenerativa por técnica minimamente invasiva Corrección de escoliosis lumbar degenerativa por técnica mínimamente invasiva Correction of degenerative lumbar scoliosis by minimally invasive technique

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    Pedro Santos Silva

    2012-12-01

    Full Text Available A terapêutica cirúrgica da escoliose degenerativa consiste habitualmente em instrumentações e fusões mais ou menos extensas e associa-se a morbilidade significativa. A evolução tecnológica tem aberto caminho a técnicas menos invasivas que permitem obter resultados sobreponíveis aos das técnicas tradicionais minimizando a agressão cirúrgica. Descreve-se o caso de uma paciente do sexo feminino, de 63 anos, submetida a descompressão lombar posterior, em Janeiro de 2009, por alterações degenerativas marcadas. Poucos meses após a cirurgia a paciente referiu aumento das lombalgias e ciatalgia direita. O estudo imagiológico demonstrou agravamento de escoliose degenerativa L2-L5 associada a extrusão discal L2-L3 direita calcificada, fractura bilateral dos pedículos de L3 e espondilolistese degenerativa grau 1 L5-S1. Foi submetida a reintervenção cirúrgica por técnica minimamente invasiva consistindo em TLIF's L2-L3, L3-L4, L4-L5 e L5-S1 e fixação transpedicular L2-S1 bilateral, com correcção da deformidade no plano sagital e coronal. O caso clínico apresentado ilustra o potencial das abordagens minimamente invasivas no tratamento cirúrgico de escolioses degenerativas, devendo ser uma opção sempre presente considerando os benefícios potenciais para o paciente.El tratamiento quirúrgico de la escoliosis degenerativa consiste habitualmente en instrumentaciones y fusiones más o menos extensas, asociadas a morbilidad significativa. La evolución tecnológica ha abierto el camino para técnicas menos invasivas que permiten obtener resultados comparables a los de las técnicas tradicionales, minimizando el trauma de la cirugía. Presentamos el caso de paciente de sexo femenino, de 63 años de edad, sometida a descompresión lumbar posterior en enero de 2009, debido a marcadas alteraciones degenerativas. Pocos meses después del procedimiento, la paciente refirió agravamiento de la lumbalgia y ciática derecha. El estudio de

  5. Influência da redução medicamentosa da pressão intra-ocular na medida da espessura da camada de fibras nervosas da retina de olhos hipertensos e glaucomatosos pela polarimetria de varredura a laser The influence of intraocular pressure reduction with medication on retinal nerve fiber layer thickness measurements obtained with scanning laser polarimetry in glaucomatous and hypertensive eyes

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    Rodrigo Rezende Gomes Avelino

    2006-10-01

    Full Text Available OBJETIVO: Avaliar o efeito da redução da pressão intra-ocular (PIO obtido com o uso de terapia medicamentosa na espessura da camada de fibras nervosas da retina medida pela polarimetria de varredura a laser (PVL em pacientes glaucomatosos ou hipertensos oculares. MÉTODOS: Trinta e sete olhos de 37 pacientes foram prospectivamente incluídos no estudo e avaliados com a PVL sem uso de medicação ocular hipotensora e num período entre 15 e 30 dias após a instituição de medicação ocular hipotensora, que resultou em redução da PIO de pelo menos 25%. Os parâmetros medidos pela PVL antes e após a redução da PIO foram comparados com o teste t de Student pareado. RESULTADOS: A PIO média dos 37 pacientes diminuiu significativamente de 26,57±4,23 mmHg para 16,54±2,92 mmHg (p0,05. CONCLUSÃO: A redução da PIO com o uso de medicação ocular hipotensora não altera a medida da espessura da camada de fibras nervosas da retina pela PVL em pacientes com glaucoma ou hipertensão ocular.PURPOSE: To evaluate changes in retinal nerve fiber layer thickness as measured by scanning laser polarimetry (SLP after the use of medication to reduce intraocular pressure (IOP in glaucomatous or ocular hypertensive patients. METHODS: The authors prospectively enrolled 37 eyes of 37 patients in whom IOP was reduced by more than 25% after the use of medication. The images were obtained before and 15 to 30 days after the introduction of medication. The SLP parameters measured before and after the use of medication were compared using paired Student's t Test. RESULTS: The mean IOP was significantly reduced from 26.57±4.23 mmHg to 16.54 ±2.92 mmHg after the use of medication (p0.05. CONCLUSION: The retinal nerve fiber layer thickness, as measured by SLP, is not affected by the reduction of IOP with medication in patients with glaucoma or ocular hypertension.

  6. Trombose de veia central da retina em paciente usuária de interferon e ribavirina: relato de caso Central vein occlusion in a patient using interferon and ribavirin: case report

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    John Helal Jr.

    2006-08-01

    Full Text Available O interferon alfa (INF alfa é droga atualmente utilizada no tratamento de várias doenças sistêmicas, como a hepatite C crônica. A ribavirina quando associada ao interferon alfa aumenta muito a resposta ao tratamento. Estima-se que a infecção crônica pelo vírus da hepatite C afete 170 milhões de pessoas no mundo, muitas delas em uso dessas medicações. A forma típica da retinopatia associada ao interferon alfa apresenta exsudatos algodonosos e hemorragias intra-retinianas. Há vários relatos de alterações oculares associadas ao uso do interferon alfa. Este trabalho descreve um caso de oclusão de veia central da retina em olho direito, com hemorragias no olho contralateral, em paciente usuária dessas medicações por dois anos. O caso descrito expõe em um dos olhos o quadro mais freqüente da retinopatia associada ao uso de interferon alfa (hemorragias de fundo e no olho contralateral, uma apresentação muito mais atípica (trombose de veia central da retina. O quadro fundoscópico apresentou melhora com a interrupção da medicação.Interferon and ribavirin are medications widely used in the treatment of some systemic diseases, mainly hepatitis C. Ribavirin when associated with interferon increases the rate of success of this treatment. There are about 170 million patients with chronic hepatitis C in the world, many in use of these medications. The classic associated retinopathy is described as cotton wool exudates and hemorrhages. Since the first reports, several different ocular disturbances were described in association with interferon. The present case shows a patient whose right eye presented with central retinal vein occlusion and whose left eye presented the typical findings of hemorrhages; prompt resolution after the medications were discontinued.

  7. Desprendimiento de retina

    Directory of Open Access Journals (Sweden)

    L. Jaime Claramunt, Dr.

    2010-11-01

    Full Text Available El desprendimiento de retina (DR consiste en la separación entre la retina neurosensorial y el epitelio pigmentario subyacente. Su forma más frecuente es el DR regmatógeno, causado por una rotura en la retina. Se manifiesta generalmente como un defecto en el campo visual o mala visión. Si se pesquisa y trata oportunamente tiene buenas posibilidades de éxito. No obstante, sigue siendo una causa importante de mala visión y ceguera, por lo que su prevención tiene un rol fundamental.

  8. Desprendimiento de retina

    OpenAIRE

    L. Jaime Claramunt, Dr.

    2010-01-01

    El desprendimiento de retina (DR) consiste en la separación entre la retina neurosensorial y el epitelio pigmentario subyacente. Su forma más frecuente es el DR regmatógeno, causado por una rotura en la retina. Se manifiesta generalmente como un defecto en el campo visual o mala visión. Si se pesquisa y trata oportunamente tiene buenas posibilidades de éxito. No obstante, sigue siendo una causa importante de mala visión y ceguera, por lo que su prevención tiene un rol fundamental.

  9. A programmable artificial retina

    International Nuclear Information System (INIS)

    Bernard, T.M.; Zavidovique, B.Y.; Devos, F.J.

    1993-01-01

    An artificial retina is a device that intimately associates an imager with processing facilities on a monolithic circuit. Yet, except for simple environments and applications, analog hardware will not suffice to process and compact the raw image flow from the photosensitive array. To solve this output problem, an on-chip array of bare Boolean processors with halftoning facilities might be used, providing versatility from programmability. By setting the pixel memory size to 3 b, the authors have demonstrated both the technological practicality and the computational efficiency of this programmable Boolean retina concept. Using semi-static shifting structures together with some interaction circuitry, a minimal retina Boolean processor can be built with less than 30 transistors and controlled by as few as 6 global clock signals. The successful design, integration, and test of such a 65x76 Boolean retina on a 50-mm 2 CMOS 2-μm circuit are presented

  10. Helping the Retina Regenerate

    Science.gov (United States)

    ... the retina News Brief 03/30/17 A new report gives recommendations for regenerating retinal ganglion cells (RGCs), crucial neurons in the back of the eye that carry visual information to the brain. Authored ...

  11. Avaliação das funções executivas em idosos acometidos por doenças crônico-degenerativas

    Directory of Open Access Journals (Sweden)

    Ivone Lúcia Brito

    2012-07-01

    Full Text Available O avanço das condições de saúde vem propiciando o aumento da longevidade e conseqüentemente uma expectativa de vida maior. Esta pesquisa foi elaborada com o objetivo de verificar a existência de déficit no desempenho das Funções Executivas em idosos acometidos com doenças crônico-degenerativas através do Teste Wisconsin de Classifica��ão de Cartas, bem como investigar patologias associadas (depressão e ansiedade e suas implicações na vida dos idosos. Participaram do estudo30 idosos de ambos os sexos, com idade igual ou superior a 60 anos, diagnosticados com doenças crônico-degenerativas (Diabetes Mellitus e Hipertensão Arterial. O delineamento foi de um estudo quantitativo e transversal, tendo como instrumentos: Ficha de Dados Sociodemográficos, Teste Wisconsin de Classificação de Cartas (WCST, Inventário de Depressão de Beck (BDI-I, Inventário de Ansiedade de Beck (BAI e Escala de Depressão Geriátrica (GDS. Os resultados apontam que os idosos demonstraram dificuldades nodesempenho das tarefas conforme descritores do WCST.Verifica-se correlações altamente significativas entre o total do escore do BAI com o GDS (r=0,667, p<0,001, o que significa que, na medida em que os sintomas de ansiedade aumentam, aumenta também os sintomas depressivos.

  12. Descolamento regmatogênico de retina: avaliação pós-operatória da mácula Rhegmatogenous retinal detachment: a postoperative study of the macula

    Directory of Open Access Journals (Sweden)

    Otacílio de Oliveira Maia Júnior

    2007-12-01

    Full Text Available OBJETIVO: Avaliar função e estrutura macular de pacientes submetidos a cirurgia de descolamento regmatogênico da retina. MÉTODOS: Estudo prospectivo de pacientes submetidos a retinopexia pneumática ou introflexão escleral com seguimento feito por meio de exame oftalmológico completo e tomografia de coerência óptica. RESULTADOS: A amostra foi composta por 14 olhos (14 pacientes, sendo 10 (71,4% submetidos a introflexão escleral e 4 (28,6%, a retinopexia pneumática. A idade variou entre 24 e 59 anos, média de 39,3 anos. Houve correlações negativas entre a acuidade visual final e a idade (r= -0,64 e p= 0,0127 e entre a acuidade visual final e o tempo de descolamento (r= -0,54 e p= 0,0447. Houve correlação positiva entre as acuidades visual do seguimento inicial e final (r= 0,69 e p= 0,0059. Na tomografia de coerência óptica, quatro olhos (28,6% apresentaram descolamento residual na fóvea, com resolução espontânea e melhora na acuidade visual (p= 0,031; não houve relação entre tempo de resolução e acuidade final (p= 0,5546. CONCLUSÃO: Os resultados mostram que quanto mais jovem o paciente e mais precoce a intervenção cirúrgica, melhor acuidade visual final. Adicionalmente, quanto maior acuidade no início do pós-operatório, melhor acuidade final. Todos os casos de descolamento foveal evidenciados por meio da tomografia de coerência óptica, no pós-operatório, cursaram com reabsorção do líquido subfoveal e melhora da visão.PURPOSE: To evaluate the structure and function of the macula following rhegmatogenous retinal detachment surgery. METHODS: Prospective study of patients submitted to scleral buckle surgery or pneumatic retinopexy. The follow-up comprised a complete ophthalmologic exam and optical coherence tomography. RESULTS: The sample was composed of 14 eyes (14 patients, 71.4% operated with the scleral buckle technique, and 28.6% with the pneumatic retinopexy. The age range was from 24 to 59 years (mean

  13. Correlação e correspondência topográfica entre espessura da camada de fibras nervosas da retina e campo visual no glaucoma primário de ângulo aberto Correlation and topographic match between nerve fiber layer thickness and visual field in primary open angle glaucoma

    Directory of Open Access Journals (Sweden)

    Paula Boturão de Almeida

    2001-04-01

    Full Text Available Objetivo: Verificar a correlação e a correspondência topográfica entre a espessura da camada de fibras nervosas da retina, medidas pelo polarímetro de varredura a laser GDxTM Scanning Laser System® e o campo visual, medido pelo perímetro automatizado Humphrey® ("white-white" em portadores de glaucoma primário de ângulo aberto. Métodos: Foram investigadas as seguintes correlações: 1- Correlação entre a média da sensibilidade dos quadrantes e do ponto de fixação do campo visual, em decibéis, e a média da espessura da camada de fibras nervosas da retina correspondente, em micra, sem classificação dos olhos dos pacientes quanto ao estadio do comprometimento perimétrico. 2- A mesma correlação anterior, porém, com os olhos dos pacientes distribuídos em classes quanto à alteração perimétrica. 3- Correlação entre os índices globais do campo visual e os índices numéricos do analisador de espessura da camada de fibras nervosas da retina. 4- Correlação entre a média dos valores do gráfico "total deviation" do campo visual e o desvio da normalidade da camada de fibras nervosas da região correspondente. 5- Investigou-se a freqüência de correspondência topográfica entre os defeitos perimétricos e as alterações da camada de fibras nervosas da retina. Utilizou-se o coeficiente de correlação de Spearman, sendo o nível de rejeição para a hipótese de nulidade fixado num valor menor ou igual a 0,05 (5%. Resultados: Observou-se as seguintes correlações estatisticamentes significantes, mas de forma muito pouco intensa: 1- GDX total e Campo visual total; GDX superior e Campo visual nasal inferior; GDX inferior e Campo visual nasal superior; GDX nasal e Campo visual temporal; GDX superior e Campo visual inferior; GDX inferior e Campo visual superior. 2- GDX inferior e Campo visual nasal (medial superior dos pacientes classificados como graves. 3- Nos olhos classificados como normais: PSD e EM; CPSD e SI.Nos olhos

  14. Selective retina therapy (SRT)

    International Nuclear Information System (INIS)

    Brinkmann, R.; Birngruber, R.

    2007-01-01

    Selective Retina Therapy (SRT) is a new and very gentle laser method developed at the Medical Laser Center Luebeck. It is currently investigated clinically in order to treat retinal disorders associated with a decreased function of the retinal pigment epithelium (RPE). SRT is designed to selectively effect the RPE while sparing the neural retina and the photoreceptors as well as the choroid. Aim of the therapy is the rejuvenation of the RPE in the treated areas, which should ideally lead to a long term metabolic increase at the chorio-retinal junction. In contrast to conventional laser photocoagulation, which is associated with a complete thermal necrosis of the treated site, SRT completely retains full vision. This paper reviews the methods and mechanisms behind selective RPE effects and reports the first clinical results. An online dosimetry technique to visualize the ophthalmoscopically invisible effects is introduced. (orig.)

  15. The infrared retina

    International Nuclear Information System (INIS)

    Krishna, Sanjay

    2009-01-01

    As infrared imaging systems have evolved from the first generation of linear devices to the second generation of small format staring arrays to the present 'third-gen' systems, there is an increased emphasis on large area focal plane arrays (FPAs) with multicolour operation and higher operating temperature. In this paper, we discuss how one needs to develop an increased functionality at the pixel level for these next generation FPAs. This functionality could manifest itself as spectral, polarization, phase or dynamic range signatures that could extract more information from a given scene. This leads to the concept of an infrared retina, which is an array that works similarly to the human eye that has a 'single' FPA but multiple cones, which are photoreceptor cells in the retina of the eye that enable the perception of colour. These cones are then coupled with powerful signal processing techniques that allow us to process colour information from a scene, even with a limited basis of colour cones. Unlike present day multi or hyperspectral systems, which are bulky and expensive, the idea would be to build a poor man's 'infrared colour' camera. We use examples such as plasmonic tailoring of the resonance or bias dependent dynamic tuning based on quantum confined Stark effect or incorporation of avalanche gain to achieve embodiments of the infrared retina.

  16. Comportamiento de la visión de color en pacientes sospechosos de glaucoma y glaucomatosos como daño precoz de las células ganglionares de la retina Colour vision of patients suspected of and diagnosed with glaucoma as an early damage of ganglionary cells of the retina

    Directory of Open Access Journals (Sweden)

    José Alberto Cabrera Martínez

    2007-06-01

    Full Text Available Se realizó un estudio descriptivo y analítico en 60 pacientes (sospechosos de glaucoma y con diagnóstico de glaucoma crónico simple estadio inicial que concurrieron a la consulta de Oftalmología del Hospital Militar Central "Dr. Carlos J. Finlay" en el período comprendido entre los años 2003 y 2006. La muestra se conformó con 30 pacientes con sospecha de glaucoma y 30 con diagnóstico de glaucoma que cumplieron los requisitos de inclusión y exclusión. Los primeros 30 pacientes de cada grupo que fueron atendidos durante ese período fueron los seleccionados. Se les aplicaron diferentes test para evaluar la visión de colores, como daño precoz de las células ganglionares de la retina. Se consideró sospechoso de glaucoma todo paciente que tuviese al menos tres de los más importantes factores de riesgos (HTO, edad mayor de 40 años, raza negra y antecedentes familiares de primer grado que padezcan la enfermedad. Se diagnosticó como glaucomatoso aquel paciente que presentó síntomas y signos de la enfermedad y alteraciones incipientes del campo visual (aumento mancha ciega, escalón nasal o escotoma Seidel. También se utilizó en el estudio una muestra de 31 sujetos supuestamente sanos de la investigación realizada en el Hospital "Hermanos Ameijeiras" bajo las mismas condiciones de exploración como grupo control -que se tituló "Estudio de la visión cromática en una población sana". El método de evaluación de los pacientes consistió en un examen inicial oftalmológico donde se recogieron sus datos generales paciente, síntomas y signos clínicos hallados, así como factores de riesgo de la enfermedad. Se constató que los sujetos sanos no presentaban alteraciones en relación con los colores y que los sospechosos y glaucomatosos sí las presentaron en un índice significativoA descriptive analytical study of 60 patients suspected of glaucoma and diagnosed with simple chronic glaucoma at initial stage, who went to the

  17. The Retina Algorithm

    CERN Multimedia

    CERN. Geneva; PUNZI, Giovanni

    2015-01-01

    Charge particle reconstruction is one of the most demanding computational tasks found in HEP, and it becomes increasingly important to perform it in real time. We envision that HEP would greatly benefit from achieving a long-term goal of making track reconstruction happen transparently as part of the detector readout ("detector-embedded tracking"). We describe here a track-reconstruction approach based on a massively parallel pattern-recognition algorithm, inspired by studies of the processing of visual images by the brain as it happens in nature ('RETINA algorithm'). It turns out that high-quality tracking in large HEP detectors is possible with very small latencies, when this algorithm is implemented in specialized processors, based on current state-of-the-art, high-speed/high-bandwidth digital devices.

  18. Corpus vitreum, retina og chorioidea biopsi

    DEFF Research Database (Denmark)

    Scherfig, Erik Christian Høegh

    2002-01-01

    oftalmology, biopsy, choroid, corpus vitreum, retina, malignant melanoma, biopsy technic, retinoblastoma......oftalmology, biopsy, choroid, corpus vitreum, retina, malignant melanoma, biopsy technic, retinoblastoma...

  19. Avaliação dos pacientes submetidos à descompressão e artrodese póstero-lateral devido à espondilolistese degenerativa com dois anos de acompanhamento Evaluación de los pacientes sometidos a descompresión y artrodesis posterolateral debido a la espondilolistesis degenerativa con dos años de seguimiento Evaluation of patients undergoing decompression and posterolateral arthrodesis because of degenerative spondylolisthesis with two years of follow up

    Directory of Open Access Journals (Sweden)

    Fernando William Figueiredo da Rosa

    2012-09-01

    Full Text Available OBJETIVO: Avaliar os resultados da descompressão e da artrodese póstero-lateral na espondilolistese degenerativa em pacientes que têm como sintoma principal a claudicação neurogênica. MÉTODO: Foram selecionados 21 pacientes com espondilolistese degenerativa, com indicação de tratamento cirúrgico. Foram avaliados 8 homens e 13 mulheres com idades entre 36 e 77 anos. O procedimento cirúrgico padronizado foi a artrodese póstero-lateral com instrumentação e descompressão associada. Os pacientes foram avaliados por VAS, índice de Oswestry e Roland-Morris no pré-operatório, com um mês, seis meses, um ano e dois anos de seguimento. Os dados foram analisados estatisticamente com nível de significância de 5%. RESULTADOS: O nível mais frequentemente operado foi L4-L5, com 52,38%. A VAS teve melhora significativa de 53,48% nos 6 meses após o procedimento. O Índice de Incapacidade de Oswestry apresentou piora no primeiro mês, evolução para melhora da capacidade até o sexto mês, e permaneceu constante até o fim do acompanhamento. Segundo o questionário de Incapacidade de Roland-Morris, houve melhora progressiva significativa até o sexto mês e, por último, uma leve piora. CONCLUSÃO: Os pacientes com espondilolistese degenerativa submetidos à artrodese póstero-lateral instrumentada e descompressão apresentaram melhora significativa da qualidade de vida e da dor após dois anos de acompanhamento.OBJETIVO: Evaluar los resultados de la descompresión y de la artrodesis posterolateral en la espondilolistesis degenerativa en pacientes que tienen, como síntoma principal, la claudicación neurogénica. MÉTODO: Se seleccionaron 21 pacientes con espondilolistesis degenerativa, con indicación de tratamiento quirúrgico. Se evaluaron 8 hombres y 13 mujeres, con edades de 36 a 77 años. El procedimiento quirúrgico estandarizado fue la artrodesis posterolateral con instrumentación y descompresión vinculada. Los pacientes fueron

  20. Evaluación de los factores epidemiológicos como predictores de los resultados postquirúrgicos en patología lumbar degenerativa

    OpenAIRE

    Lozano Álvarez, Carlos

    2011-01-01

    Els resultats del tractament quirúrgic per dolor lumbar crònic i patologia degenerativa lumbar, patologies d'elevada prevalença i despesa sanitària, estan afectats per múltiples factors. En aquest treball hem estudiat com les característiques epidemiològiques dels pacients de la nostra població influeixen sobre el canvi de la qualitat de vida, la discapacitat i el dolor després de cirurgies per patologia lumbar degenerativa. Del nostre estudi, d'acord amb la revisió realitzada de la literatur...

  1. Factores de riesgo asociados a la demencia degenerativa en pacientes geriátricos

    Directory of Open Access Journals (Sweden)

    Alejandro Rodríguez Constantín

    2003-04-01

    Full Text Available Se realizó un estudio analítico de tipo caso-control, para determinar factores de riesgo asociados a la aparición de demencia degenerativa en pacientes geriátricos pertenecientes al Consejo Popular "Los Maceo", del Policlínico Docente "Carlos J. Finlay", de la ciudad de Santiago de Cuba, desde septiembre a diciembre del año 2000. La muestra se constituyó con 22 casos identificados previamente como dementes degenerativos por el Equipo Multidisciplinario Gerontológico y 66 controles. Se aplicó una encuesta y se realizó el análisis de los resultados obtenidos. Se calcularon los odds radio (OR correspondientes a cada variable. El bajo nivel de escolaridad (OR=3,99, y el antecedente patológico familiar de demencia (OR=3,01 fueron identificados como factores de riesgo. No presentaron asociación causal las variables sexo (OR=1,46; modificaciones intensas del tono emocional (OR=1 y cambio brusco repetitivo del entorno habitacional (OR=1. La ejercitación de la capacidad intelectual después de los 60 años (OR=0,8 se consideró factor protector.A case control-type analytical study was made to determine the risk factors associated to the occurrence of degenerative dementia in old patients living in the people´s council "Los Maceo", whose population is taken care of by "Carlos J. Finlay" teaching polyclinics in Santiago de Cuba City. The sample was made up of 22 cases previously diagnosed as degenerative dements by the Multidisciplinary Gerontology Team and 66 controls. A survey was administered and the results achieved were analyzed. Odd ratios of each variable were estimated. Low educational level (OR=3,99 and the pathological family history of dementia (OR = 3.01 were identified as risk factors. No causal relation was observed among sex, intensive changes in emotional state and sudden repetitive change of the living environment (0R=1. The exercising of intellectual abilities after 60 years of age was considered to be a protective factor.

  2. Impacto do equilíbrio espinopélvico nos resultados clínicos e funcionais após artrodese instrumentada em doentes com espondilolistese degenerativa

    Directory of Open Access Journals (Sweden)

    Filipe Rodrigues Duarte

    2013-01-01

    Full Text Available OBJETIVO: Garantir o equilíbrio sagital e pélvico depois de correção cirúrgica de deformidade lombar tem sido alvo de atenção crescente na literatura. Estudos recentes demonstraram uma relação entre o equilíbrio espinopélvico e o resultado pós-operatório. Com a progressão da deformidade degenerativa, as alterações correspondentes dos parâmetros pélvicos são evidentes. Assim, os autores pretendem estudar a influência do equilíbrio espinopélvico nos resultados clínicos e funcionais após cirurgia de espondilolistese degenerativa (ED. MÉTODOS: Estudo retrospectivo. Amostra com 29 indivíduos com ED submetidos a descompressão e artrodese instrumentada entre 2006 e 2010. Média de idade 65,45 (± 8,15 anos. 20 mulheres e 9 homens. Acompanhamento médio - 2,1 anos. Avaliação clínica, funcional e radiológica. VAS, satisfação global, Oswestry Disability Index modificado. Cálculo de incidência pélvica, inclinação sacral, versão pélvica e lordose lombar. Dois grupos de estudo: A (n = 14: sem melhoria da versão pélvica (aumentada ou inalterada no pós-operatorio. B (n = 15: com melhoria da versão pélvica (diminuída. Estudo estatístico com SPSS®. RESULTADOS: A cirurgia é benéfica, reduz significativamente a dor e melhora a qualidade de vida. Os pacientes do grupo B (restituição do balanço original apresentam melhores resultados clínicos e funcionais (p < 0,05 e valores superiores de incidência pélvica relativamente ao grupo A. CONCLUSÃO: Este trabalho confirma a importância do equilíbrio espinopélvico como objetivo no planeamento cirúrgico e que a restituição do equilíbrio original parece obter melhores resultados.

  3. Fine structure of the retinal pigment epithelium and cones of Antarctic fish Notohenia coriiceps Richardson in light and dark-conditions Ultraestrutra do epitélio pigmentar da retina e dos cones do peixe Antártico Notothenia coriiceps Richardson submetido à luz e ao escuro

    Directory of Open Access Journals (Sweden)

    Lucélia Donatti

    2007-03-01

    Full Text Available The Antarctic fish Notothenia coriiceps Richardson, 1844 lives in an environment of daily and annual photic variation and retina cells have to adjust morphologically to environmental luminosity. After seven day dark or seven day light acclimation of two groups of fish, retinas were extracted and processed for light and transmission electron microscopy. In seven day dark adapted, retina pigment epithelium melanin granules were aggregated at the basal region of cells, and macrophages were seen adjacent to the apical microvilli, between the photoreceptors. In seven day light adapted epithelium, melanin granules were inside the apical microvilli of epithelial cells and macrophages were absent. The supranuclear region of cones adapted to seven day light had less electron dense cytoplasm, and an endoplasmic reticulum with broad tubules. The mitochondria in the internal segment of cones adapted to seven day light were larger, and less electron dense. The differences in the morphology of cones and pigment epithelial cells indicate that N. coriiceps has retinal structural adjustments presumably optimizing vision in different light conditions.O peixe Antártico Notothenia coriiceps Richardson, 1844 habita meios com variações fóticas diária e anual e as células da retina se adaptam morfologicamente a esta luminosidade ambiental. Dois grupos de peixes foram aclimatados durante sete dias à luz constante ou ao escuro constante. Após secção medular, as retinas foram extraídas e processadas para microscopia de luz e microscopia eletrônica de transmissão. No epitélio pigmentar da retina adaptado sete dias ao escuro, os pigmentos de melanina agregam-se na base coroidal das células epiteliais pigmentares e macrófagos são encontrados no interior do processos apicais entre as células fotorreceptoras. No epitélio adaptado sete dias à luz os pigmentos de melanina se dispõem ao longo das projeções apicais das células epiteliais pigmentares e os

  4. Imaging of the peripheral retina

    Directory of Open Access Journals (Sweden)

    Marcus Kernt

    2013-01-01

    Full Text Available The technical progress of the recent years has revolutionized imaging in ophthalmology. Scanning laser ophthalmoscopy (SLO, digital angiography, optical coherence tomography (OCT, and detection of fundus autofluorescence (FAF have fundamentally changed our understanding of numerous retinal and choroidal diseases. Besides the tremendous advances in macular diagnostics, there is more and more evidence that central pathologies are often directly linked to changes in the peripheral retina. This review provides a brief overview on current posterior segment imaging techniques with a special focus on the peripheral retina.

  5. Selective retina therapy (SRT); Selektive Retina-Therapie (SRT)

    Energy Technology Data Exchange (ETDEWEB)

    Brinkmann, R.; Birngruber, R. [Luebeck Univ. (Germany). Inst. fuer Biomedizinische Optik; Medizinisches Laserzentrum Luebeck GmbH, Luebeck (Germany)

    2007-07-01

    Selective Retina Therapy (SRT) is a new and very gentle laser method developed at the Medical Laser Center Luebeck. It is currently investigated clinically in order to treat retinal disorders associated with a decreased function of the retinal pigment epithelium (RPE). SRT is designed to selectively effect the RPE while sparing the neural retina and the photoreceptors as well as the choroid. Aim of the therapy is the rejuvenation of the RPE in the treated areas, which should ideally lead to a long term metabolic increase at the chorio-retinal junction. In contrast to conventional laser photocoagulation, which is associated with a complete thermal necrosis of the treated site, SRT completely retains full vision. This paper reviews the methods and mechanisms behind selective RPE effects and reports the first clinical results. An online dosimetry technique to visualize the ophthalmoscopically invisible effects is introduced. (orig.)

  6. Towards photovoltaic powered artificial retina

    Directory of Open Access Journals (Sweden)

    Santiago Silvestre

    2011-11-01

    Full Text Available The aim of this article is to provide an overview of current and future concepts in the field of retinal prostheses, and is focused on the power supply based on solar energy conversion; we introduce the possibility of using PV minimodules as power supply for a new concept of retinal prostheses: Photovoltaic Powered Artificial Retina (PVAR. Main characteristics of these PV modules are presented showing its potential for this application.

  7. Prevalência e relação de fatores emocionais e clínicos em pacientes com discopatia degenerativa La prevalencia y la relación de los factores clínicos y los trastornos emocionales en pacientes con discopatia degenerativa del disco Prevalence and relationship of emotional and clinical factors in patients with degenerative disc disease

    Directory of Open Access Journals (Sweden)

    Vivian Amaral

    2010-06-01

    Full Text Available OBJETIVOS: descrever as condições psicossociais, no momento da indicação cirúrgica, dos pacientes com dor lombar crônica causada por discopatia degenerativa. MÉTODOS: em uma série de 32 casos de discopatia degenerativa eletivos para cirurgia, foi realizada avaliação psicológica pré-operatória. Nesta avaliação, foram colhidos dados demográficos e sociais: sexo, idade, situação ocupacional atual, ocorrência de afastamento por invalidez; e dados clínico-psicológicos: dor, restrição física, utilização de medicamento psiquiátrico controlado; grau de ansiedade; grau de depressão; grau de desesperança; expectativas frente ao objetivo cirúrgico. RESULTADOS: o grupo foi composto de 13 mulheres e 14 homens, com média de idade de 44,3 anos (23 a 65 anos. Os parâmetros de dor e restrição física estão dentro de valores geralmente indicativos de cirurgia, não indicando nenhuma peculiaridade no grupo estudado. Foi evidenciada uma alta e correlacionada prevalência de alterações psicológicas nos pacientes: 50% em quadro depressivo, 54% em quadro de ansiedade e 22% em quadro de desesperança. Além disso, foi possível evidenciar altos índices de afastamento do trabalho por invalidez física e correlação da presença de ansiedade e/ou depressão com casos em que haviam expectativas deturpadas quanto ao resultado cirúrgico. CONCLUSÕES: dor lombar crônica é acompanhada de quadros de dor e de alterações psicológicas, como ansiedade, depressão e desesperança. Esses parâmetros evidenciam a necessidade de avaliação psicológica pré-cirúrgica e acompanhamento posterior, visando à reabilitação do paciente.OBJETIVOS: describir las condiciones psicosociales, en el momento de la indicación quirúrgica, de pacientes con dolor lumbar crónico causado por discopatia degenerativa del disco. MÉTODOS: en una serie de 32 casos de discopatia degenerativa del disco, se llevó a cabo una evaluación psicológica antes de

  8. Adenosine as a signaling molecule in the retina: biochemical and developmental aspects

    Directory of Open Access Journals (Sweden)

    ROBERTO PAES-DE-CARVALHO

    2002-09-01

    neurotransmissores tais como dopamina ou glutamato, liberam o nucleosídeo através de mecanismos dependentes de cálcio e mediados por transportador. A presença de adenosina no meio extracelular e a ativação duradoura dos receptores de adenosina regula a sobrevivência de neurônios da retina e bloqueia a excitoxicidade mediada por glutamato. Desse modo, a adenosina, além de apresentar a função de neurotransmissor ou neuromodulador na retina desenvolvida, é considerada como uma molécula importante durante o desenvolvimento da retina, apresentando funções como a regulação da sobrevivência e diferenciação neuronal.

  9. [Lattice degeneration of the retina].

    Science.gov (United States)

    Boĭko, E V; Suetov, A A; Mal'tsev, D S

    2014-01-01

    Lattice degeneration of the retina is a clinically important type of peripheral retinal dystrophies due to its participation in the pathogenesis of rhegmatogenous retinal detachment. In spite of extensive epidemiological, morphological, and clinical data, the question on causes of this particular type of retinal dystrophies currently remains debatable. Existing hypotheses on pathogenesis of retinal structural changes in lattice degeneration explain it to a certain extent. In clinical ophthalmology it is necessary to pay close attention to this kind of degenerations and distinguish between cases requiring preventive treatment and those requiring monitoring.

  10. Lattice degeneration of the retina.

    Science.gov (United States)

    Byer, N E

    1979-01-01

    Lattice degeneration of the retina is the most important of all clinically distinct entities that effect the peripheral fundus and are related to retinal detachment. The purpose of this review is to survey the extensive literature, to evaluate the many diverse opinions on this subject, and to correlate and summarize all the known facts regarding this disease entity. The disease is fully defined and described, both clinically and histologically. Some aspects of the disease are still poorly understood, and some remain controversial, especially in the area of management. For this reason, the indications for treatment are discussed under eight subsections, with a view toward providing practical guidelines for recommendations in management.

  11. Acetylcholine receptors in the human retina

    International Nuclear Information System (INIS)

    Hutchins, J.B.; Hollyfield, J.G.

    1985-01-01

    Evidence for a population of acetylcholine (ACh) receptors in the human retina is presented. The authors have used the irreversible ligand 3 H-propylbenzilylcholine mustard ( 3 H-PrBCM) to label muscarinic receptors. 3 H- or 125 I-alpha-bungarotoxin (alpha-BTx) was used to label putative nicotinic receptors. Muscarinic receptors are apparently present in the inner plexiform layer of the retina. Autoradiographic grain densities are reduced in the presence of saturating concentrations of atropine, quinuclidinyl benzilate or scopolamine; this indicates that 3 H-PrBCM binding is specific for a population of muscarinic receptors in the human retina. Binding sites for radiolabeled alpha-BTx are found predominantly in the inner plexiform layer of the retina. Grain densities are reduced in the presence of d-tubocurarine, indicating that alpha-BTx may bind to a pharmacologically relevant nicotinic ACh receptor. This study provides evidence for cholinergic neurotransmission in the human retina

  12. Cansancio, cuidados y repercusiones en cuidadores informales de adultos mayores con enfermedades crónico degenerativas

    Directory of Open Access Journals (Sweden)

    María Asunción Vicente Ruiz

    2016-08-01

    Full Text Available Las enfermedades crónicas como diabetes, hipertensión, enfermedad cardiovascular, cáncer, pueden limitar la habilidad de los adultos mayores para ejecutar actividades de la vida diaria, generando cansancio o sobrecarga en los cuidadores. Objetivo: Determinar la relación que existe entre el cansancio, el cuidado y los efectos a la salud del cuidador. Metodología: Estudio cuantitativo y analítico. La muestra se conformó con 123 cuidadores familiares y 123 personas adultas con enfermedad crónico degenerativa. El tipo de muestreo fue no probabilístico. Resultados y Discusión: Se encontró asociación entre el cansancio y las repercusiones del cuidado (r=.438, p<.01, lo que sugiere que mayor cansancio en los cuidadores, mayores serán las repercusiones en la salud. Además correlación de los cuidados que presta el cuidador con las repercusiones en la salud del cuidador (r=.546, p<.01, así a mayor cantidad y complejidad de los cuidados, mayores serán las repercusiones que afecten el bienestar del cuidador. Los cuidados se relacionaron con el cansancio, se afirma que a mayor cantidad y complejidad del cuidado mayor cansancio percibe el cuidador (r=.109, p<.01. Conclusión: El cansancio en los cuidadores es elevado, está asociado a la sobrecarga del cuidado con serias repercusiones en la salud o bienestar y fundamenta las intervenciones interdisciplinarias futuras.

  13. Cytogenesis in the monkey retina

    International Nuclear Information System (INIS)

    La Vail, M.M.; Rapaport, D.H.; Rakic, P.

    1991-01-01

    Time of cell origin in the retina of the rhesus monkey (Macaca mulatta) was studied by plotting the number of heavily radiolabeled nuclei in autoradiograms prepared from 2- to 6-month-old animals, each of which was exposed to a pulse of 3H-thymidine (3H-TdR) on a single embryonic (E) or postnatal (P) day. Cell birth in the monkey retina begins just after E27, and approximately 96% of cells are generated by E120. The remaining cells are produced during the last (approximately 45) prenatal days and into the first several weeks after birth. Cell genesis begins near the fovea, and proceeds towards the periphery. Cell division largely ceases in the foveal and perifoveal regions by E56. Despite extensive overlap, a class-specific sequence of cell birth was observed. Ganglion and horizontal cells, which are born first, have largely congruent periods of cell genesis with the peak between E38 and E43, and termination around E70. The first labeled cones were apparent by E33, and their highest density was achieved between E43 and E56, tapering to low values at E70, although some cones are generated in the far periphery as late as E110. Amacrine cells are next in the cell birth sequence and begin genesis at E43, reach a peak production between E56 and E85, and cease by E110. Bipolar cell birth begins at the same time as amacrines, but appears to be separate from them temporally since their production reaches a peak between E56 and E102, and persists beyond the day of birth. Mueller cells and rod photoreceptors, which begin to be generated at E45, achieve a peak, and decrease in density at the same time as bipolar cells, but continue genesis at low density on the day of birth. Thus, bipolar, Mueller, and rod cells have a similar time of origin

  14. Conduta na lesão dural intraoperatória em artrodese da coluna lombar

    OpenAIRE

    Grandese, Fabiano de Mendonça; Yamazato, Clóvis; Oliveira, Fábio Mastromauro de; Ribeiro, Iberê; Bastos Júnior, José Olympio Catão; Kusabara, René

    2010-01-01

    OBJETIVO: estudo retrospectivo de pacientes com lesão dural intraoperatória de cirurgia da coluna vertebral lombar, conduzido por meio de um protocolo independente da extensão da lesão, complicações associadas e resultados após seguimento mínimo de um ano. MÉTODOS: um total de 10 pacientes com durotomia acidental em cirurgias de descompressão e artrodese da coluna vertebral lombar, no período de Janeiro de 2007 a Janeiro de 2009, para tratamento de doença degenerativa, tiveram seus prontuário...

  15. Complex computation in the retina

    Science.gov (United States)

    Deshmukh, Nikhil Rajiv

    Elucidating the general principles of computation in neural circuits is a difficult problem requiring both a tractable model circuit as well as sophisticated measurement tools. This thesis advances our understanding of complex computation in the salamander retina and its underlying circuitry and furthers the development of advanced tools to enable detailed study of neural circuits. The retina provides an ideal model system for neural circuits in general because it is capable of producing complex representations of the visual scene, and both its inputs and outputs are accessible to the experimenter. Chapter 2 describes the biophysical mechanisms that give rise to the omitted stimulus response in retinal ganglion cells described in Schwartz et al., (2007) and Schwartz and Berry, (2008). The extra response to omitted flashes is generated at the input to bipolar cells, and is separable from the characteristic latency shift of the OSR apparent in ganglion cells, which must occur downstream in the circuit. Chapter 3 characterizes the nonlinearities at the first synapse of the ON pathway in response to high contrast flashes and develops a phenomenological model that captures the effect of synaptic activation and intracellular signaling dynamics on flash responses. This work is the first attempt to model the dynamics of the poorly characterized mGluR6 transduction cascade unique to ON bipolar cells, and explains the second lobe of the biphasic flash response. Complementary to the study of neural circuits, recent advances in wafer-scale photolithography have made possible new devices to measure the electrical and mechanical properties of neurons. Chapter 4 reports a novel piezoelectric sensor that facilitates the simultaneous measurement of electrical and mechanical signals in neural tissue. This technology could reveal the relationship between the electrical activity of neurons and their local mechanical environment, which is critical to the study of mechanoreceptors

  16. Atrofia girata de coróide e retina : relato de caso

    Directory of Open Access Journals (Sweden)

    Oyamaguchi Emerson Kenji

    2003-01-01

    Full Text Available OBJETIVO: Relatar um caso de atrofia girata de coróide e retina com confirmação por meio da bioquímica do plasma. MÉTODO: Aferiu-se a melhor acuidade visual corrigida de ambos olhos (AO em tabela de Snellen. Foram realizados biomicroscopia do segmento anterior, refração, mapeamento de retina, angiografia fluoresceínica, campo visual e dosagem da ornitina sérica (aminoacidograma. RESULTADOS: Paciente de 22 anos, sexo feminino, cor branca, apresentando alta miopia e acuidade visual (AV 20/100 em AO. À biomicroscopia do segmento anterior apresentava catarata subcapsular posterior em AO. À oftalmoscopia foram verificadas lesões atróficas da coróide e da retina bem delimitadas em meia periferia de AO. O aminoacidograma constatou elevação correspondente ao complexo da ornitina. CONCLUSÃO: Relata-se um caso típico de atrofia girata, distrofia retiniana rara associada a hiperornitinemia.

  17. Análise de Fourier para detecção de defeitos localizados na camada de fibras nervosas da retina com a polarimetria a laser Fourier analysis for the detection of localized nerve fiber layer defects using scanning laser polarimetry

    Directory of Open Access Journals (Sweden)

    Felipe Andrade Medeiros

    2003-12-01

    Full Text Available OBJETIVO: Avaliar a utilidade da análise de Fourier como método para detecção de defeitos localizados na camada de fibras nervosas da retina (CFN, utilizando as medidas obtidas com a polarimetria de varredura a laser. MÉTODOS: O estudo incluiu 40 olhos de 40 pacientes com glaucoma apresentando defeitos localizados na CFN detectados à oftalmoscopia e/ou em fotografias da camada de fibras nervosas. O grupo controle foi constituído por 43 olhos de 43 pacientes normais, sem antecedente de pressão intra-ocular elevada ou glaucoma, e com exame normal da CFN e disco óptico. Todos os pacientes foram submetidos a exame da CFN utilizando o aparelho GDx® - Nerve Fiber Analyzer. Para comparação entre os grupos, foram utilizados os parâmetros fornecidos pelo software do aparelho e medidas provenientes dos coeficientes obtidos pela análise de Fourier da curva de distribuição dos valores de espessura da CFN. As várias medidas dos coeficientes de Fourier foram combinadas numa função linear discriminante de maneira a encontrar a combinação que resultasse na melhor separação entre pacientes glaucomatosos com defeitos localizados e os sujeitos normais. Curvas ROC foram construídas para cada medida e valores de sensibilidade para especificidades fixas foram calculados. RESULTADOS: Os parâmetros fornecidos pelo software do GDx mostraram baixo poder de diferenciação entre os pacientes normais e com defeitos localizados na CFN, com sensibilidades variando de 15 a 48% (com especificidade a 91%. Para a mesma especificidade de 91%, a combinação dos coeficientes de Fourier teve sensibilidade de 80%. A área sob a curva ROC para a combinação dos coeficientes de Fourier (0,90 foi significativamente superior à obtida para o parâmetro The Number (0,76. CONCLUSÃO: A análise de Fourier resultou em melhora na capacidade do GDx de detectar defeitos localizados na CFN em relação aos parâmetros fornecidos pelo software do aparelho.PURPOSE: In

  18. An analog silicon retina with multichip configuration.

    Science.gov (United States)

    Kameda, Seiji; Yagi, Tetsuya

    2006-01-01

    The neuromorphic silicon retina is a novel analog very large scale integrated circuit that emulates the structure and the function of the retinal neuronal circuit. We fabricated a neuromorphic silicon retina, in which sample/hold circuits were embedded to generate fluctuation-suppressed outputs in the previous study [1]. The applications of this silicon retina, however, are limited because of a low spatial resolution and computational variability. In this paper, we have fabricated a multichip silicon retina in which the functional network circuits are divided into two chips: the photoreceptor network chip (P chip) and the horizontal cell network chip (H chip). The output images of the P chip are transferred to the H chip with analog voltages through the line-parallel transfer bus. The sample/hold circuits embedded in the P and H chips compensate for the pattern noise generated on the circuits, including the analog communication pathway. Using the multichip silicon retina together with an off-chip differential amplifier, spatial filtering of the image with an odd- and an even-symmetric orientation selective receptive fields was carried out in real time. The analog data transfer method in the present multichip silicon retina is useful to design analog neuromorphic multichip systems that mimic the hierarchical structure of neuronal networks in the visual system.

  19. Diseño y evaluación de microesferas biodegradables de agentes neuroprotectores para el tratamiento de patologías degenerativas que afectan al segmento posterior del ojo

    OpenAIRE

    Checa Casalengua, Patricia

    2012-01-01

    Las patologías neurodegenerativas que afectan al segmento posterior del ojo se caracterizan por ser devastadoras y comprometer la visión en un gran número de sujetos. Representan un grupo de enfermedades que cursan con un daño progresivo del nervio óptico y pérdida de fotorreceptores y células ganglionares de la retina (CGR), que sin un tratamiento continuado, pueden conducir a ceguera irreversible. Las nuevas tendencias en el tratamiento de estas enfermedades neurodegenerativas oculares e...

  20. Heterogeneous transgene expression in the retinas of the TH-RFP, TH-Cre, TH-BAC-Cre and DAT-Cre mouse lines.

    Science.gov (United States)

    Vuong, H E; Pérez de Sevilla Müller, L; Hardi, C N; McMahon, D G; Brecha, N C

    2015-10-29

    Transgenic mouse lines are essential tools for understanding the connectivity, physiology and function of neuronal circuits, including those in the retina. This report compares transgene expression in the retina of a tyrosine hydroxylase (TH)-red fluorescent protein (RFP) mouse line with three catecholamine-related Cre recombinase mouse lines [TH-bacterial artificial chromosome (BAC)-, TH-, and dopamine transporter (DAT)-Cre] that were crossed with a ROSA26-tdTomato reporter line. Retinas were evaluated and immunostained with commonly used antibodies including those directed to TH, GABA and glycine to characterize the RFP or tdTomato fluorescent-labeled amacrine cells, and an antibody directed to RNA-binding protein with multiple splicing to identify ganglion cells. In TH-RFP retinas, types 1 and 2 dopamine (DA) amacrine cells were identified by their characteristic cellular morphology and type 1 DA cells by their expression of TH immunoreactivity. In the TH-BAC-, TH-, and DAT-tdTomato retinas, less than 1%, ∼ 6%, and 0%, respectively, of the fluorescent cells were the expected type 1 DA amacrine cells. Instead, in the TH-BAC-tdTomato retinas, fluorescently labeled AII amacrine cells were predominant, with some medium diameter ganglion cells. In TH-tdTomato retinas, fluorescence was in multiple neurochemical amacrine cell types, including four types of polyaxonal amacrine cells. In DAT-tdTomato retinas, fluorescence was in GABA immunoreactive amacrine cells, including two types of bistratified and two types of monostratified amacrine cells. Although each of the Cre lines was generated with the intent to specifically label DA cells, our findings show a cellular diversity in Cre expression in the adult retina and indicate the importance of careful characterization of transgene labeling patterns. These mouse lines with their distinctive cellular labeling patterns will be useful tools for future studies of retinal function and visual processing. Published by Elsevier

  1. Radioadaptive Cytoprotective Pathways in the Mouse Retina

    Science.gov (United States)

    Zanello, Susana B.; Wotring, V.; Theriot, C.; Ploutz-Snyder, R.; Zhang, Y.; Wu, H.

    2010-01-01

    Exposure to cosmic radiation implies a risk of tissue degeneration. Radiation retinopathy is a complication of radiotherapy and exhibits common features with other retinopathies and neuropathies. Exposure to a low radiation dose elicits protective cellular events (radioadaptive response), reducing the stress of a subsequent higher dose. To assess the risk of radiation-induced retinal changes and the extent to which a small priming dose reduces this risk, we used a mouse model exposed to a source of Cs-137-gamma radiation. Gene expression profiling of retinas from non-irradiated control C57BL/6J mice (C) were compared to retinas from mice treated with a low 50 mGy dose (LD), a high 6 Gy dose (HD), and a combined treatment of 50 mGy (priming) and 6 Gy (challenge) doses (LHD). Whole retina RNA was isolated and expression analysis for selected genes performed by RTqPCR. Relevant target genes associated with cell death/survival, oxidative stress, cellular stress response and inflammation pathways, were analyzed. Cellular stress response genes were upregulated at 4 hr after the challenge dose in LHD retinas (Sirt1: 1.5 fold, Hsf1: 1.7 fold, Hspa1a: 2.5 fold; Hif1a: 1.8 fold, Bag1: 1.7). A similar trend was observed in LD animals. Most antioxidant enzymes (Hmox1, Sod2, Prdx1, Cygb, Cat1) and inflammatory mediators (NF B, Ptgs2 and Tgfb1) were upregulated in LHD and LD retinas. Expression of the pro-survival gene Bcl2 was upregulated in LD (6-fold) and LHD (4-fold) retinas. In conclusion, cytoprotective gene networks activation in the retina suggests a radioadaptive response to a priming irradiation dose, with mitigation of the deleterious effects of a subsequent high dose exposure. The enhancement of these cytoprotective mechanisms has potential value as a countermeasure to ocular alterations caused by radiation alone or in combination with other factors in spaceflight environments.

  2. An experimental platform for systemic drug delivery to the retina.

    LENUS (Irish Health Repository)

    Campbell, Matthew

    2009-10-20

    Degenerative retinopathies, including age-related macular degeneration, diabetic retinopathy, and hereditary retinal disorders--major causes of world blindness--are potentially treatable by using low-molecular weight neuroprotective, antiapoptotic, or antineovascular drugs. These agents are, however, not in current systemic use owing to, among other factors, their inability to passively diffuse across the microvasculature of the retina because of the presence of the inner blood-retina barrier (iBRB). Moreover, preclinical assessment of the efficacies of new formulations in the treatment of such conditions is similarly compromised. We describe here an experimental process for RNAi-mediated, size-selective, transient, and reversible modulation of the iBRB in mice to molecules up to 800 Da by suppression of transcripts encoding claudin-5, a protein component of the tight junctions of the inner retinal vasculature. MRI produced no evidence indicative of brain or retinal edema, and the process resulted in minimal disturbance of global transcriptional patterns analyzed in neuronal tissue. We show that visual function can be improved in IMPDH1(-\\/-) mice, a model of autosomal recessive retinitis pigmentosa, and that the rate of photoreceptor cell death can be reduced in a model of light-induced retinal degeneration by systemic drug delivery after reversible barrier opening. These findings provide a platform for high-throughput drug screening in models of retinal degeneration, and they ultimately could result in the development of a novel "humanized" approach to therapy for conditions with little or no current forms of treatment.

  3. Neurotransmitter properties of the newborn human retina

    International Nuclear Information System (INIS)

    Hollyfield, J.G.; Frederick, J.M.; Rayborn, M.E.

    1983-01-01

    Human retinal tissue from a newborn was examined autoradiographically for the presence of high-affinity uptake and localization of the following putative neurotransmitters: dopamine, glycine, GABA, aspartate, and glutamate. In addition, the dopamine content of this newborn retina was measured by high pressure liquid chromatography. Our study reveals that specific uptake mechanisms for 3 H-glycine, 3 H-dopamine, and 3 H-GABA are present at birth. However, the number and distribution of cells labeled with each of these 3 H-transmitters are not identical to those observed in adult human retinas. Furthermore, the amount of endogenous dopamine in the newborn retina is approximately 1/20 the adult level. Photoreceptor-specific uptake of 3 H-glutamate and 3 H-aspartate are not observed. These findings indicate that, while some neurotransmitter-specific properties are present at birth, significant maturation of neurotransmitter systems occurs postnatally

  4. Retina image–based optic disc segmentation

    Directory of Open Access Journals (Sweden)

    Ching-Lin Wang

    2016-05-01

    Full Text Available The change of optic disc can be used to diagnose many eye diseases, such as glaucoma, diabetic retinopathy and macular degeneration. Moreover, retinal blood vessel pattern is unique for human beings even for identical twins. It is a highly stable pattern in biometric identification. Since optic disc is the beginning of the optic nerve and main blood vessels in retina, it can be used as a reference point of identification. Therefore, optic disc segmentation is an important technique for developing a human identity recognition system and eye disease diagnostic system. This article hence presents an optic disc segmentation method to extract the optic disc from a retina image. The experimental results show that the optic disc segmentation method can give impressive results in segmenting the optic disc from a retina image.

  5. [Degenerative lesions of the peripheral retina].

    Science.gov (United States)

    Conart, J-B; Baron, D; Berrod, J-P

    2014-01-01

    Degenerative lesions of the peripheral retina are present from teenage years onwards and increase with age. These abnormabilities are frequent, some of them being benign while others predispose to retinal tears and detachment. In the latter case, the lesions are rhegmatogenous and may justify prophylactic treatment by laser photocoagulation. We distinguish congenital lesions of the peripheral retina and intraretinal, chorioretinal and vitreoretinal degenerations. The holes and tears observed in 2% of the population consist of round atrophic holes, "horseshoe" tears, oral dialyses and giant tears. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  6. Genetics of lattice degeneration of the retina.

    Science.gov (United States)

    Murakami, F; Ohba, N

    1982-01-01

    First-degree relatives of proband patients with lattice degeneration of the retina revealed a significantly higher prevalence of the disease than the prevalence in the general population: the former had the disease about three times as frequently as the latter. The observed data were analyzed in terms of their accordance with recognized genetic models. The inheritance pattern did not fit well to a monogenic mode of inheritance, and it was hypothesized that a polygenic or multifactorial mode of inheritance is the most likely for lattice degeneration of the retina.

  7. Avaliação retrospectiva por meio do questionário SF-36 de pacientes submetidos à estabilização dinâmica pedicular para o tratamento de doenças degenerativas lombares Evaluación retrospectiva empleando el cuestionario SF-36 en pacientes sometidos a estabilización dinámica pedicular para el tratamiento de la enfermedad degenerativa lumbar Retrospective evaluation by means of SF-36 questionnaires of patients submitted to pedicular dynamic stabilization for degenerative lumbar diseases treatment

    Directory of Open Access Journals (Sweden)

    Leonardo Fonseca Rodrigues

    2010-06-01

    Full Text Available INTRODUÇÃO: a estabilização dinâmica pedicular tem sido utilizada desde os anos 1990 para o tratamento da doença lombar degenerativa como uma alternativa aos métodos de fusão. Devido às suas características de não-fusão, estes implantes tendem a reduzir a carga nos discos intervertebrais adjacentes e na coluna posterior, com o objetivo de não prejudicar a biomecânica da coluna, diminuindo assim a chance de degeneração do disco adjacente. OBJETIVO: O objetivo deste estudo retrospectivo foi avaliar, por meio do questionário SF-36, os resultados dos pacientes que se submeteram à estabilização dinâmica pedicular para o tratamento da patologia degenerativa lombar. MÉTODOS: foram avaliados 31 pacientes que se submeteram à estabilização dinâmica pedicular, de abril de 2004 a junho de 2008, por meio do questionário de qualidade de vida SF-36. RESULTADOS: o SF-36 mostrou um índice de melhora na qualidade de vida desses pacientes durante o período de acompanhamento, variando de 33,15% no pré-operatório, para 75,99% no pós-operatório, correspondente a uma diferença de 129% no resultado final, que é significativo estatisticamente de acordo com o teste t de student (pINTRODUCCIÓN: la estabilización dinámica pedicular ha sido empleada desde los años 1990 en el tratamiento de la enfermedad degenerativa lumbar y como una alternativa a los métodos de fusión. Debido a sus características de no requerir fusión, estos implantes tiendes a reducir la carga sobre los disco intervertebrales adyacentes y sobre la columna posterior, con el propósito de no afectar la biomecánica vertebral. Por lo tanto, disminuye la degeneración de discos adyacentes. OBJETIVO: esto estudio retrospectivo tiene la finalidad de evaluar los resultados obtenidos al emplear el cuestionario SF-36, en pacientes que han presentado estabilización dinámica pedicular durante el tratamiento de la patología degenerativa da columna lumbar. M

  8. Efeitos da fisioterapia aquática na qualidade de vida de sujeitos com doença de Parkinson

    OpenAIRE

    Silva, Douglas Monteiro da; Nunes, Mariela Cája Oliveira; Oliveira, Paulo José de Andrade Lira; Coriolano, Maria das Graças Wanderley de Sales; Berenguer, Flávia de Araújo; Lins, Otávio Gomes; Ximenes, Dayanna Karla Gonzaga

    2013-01-01

    A doença de Parkinson (DP) é uma doença degenerativa e progressiva do sistema nervoso central, e seus sintomas podem proporcionar um declínio da qualidade de vida (QV) dos pacientes, que pode ser influenciada positivamente pela fisioterapia aquática (FA). A FA é um recurso fisioterapêutico que utiliza os efeitos físicos, fisiológicos e cinesiológicos advindos da imersão do corpo em piscina aquecida. O questionário da doença de Parkinson 39 (PDQ-39) é o instrumento mais apropriado para a avali...

  9. Capacidade antioxidante da microalga Spirulina platensis em células da levedura Saccharomyces cerevisiae submetidas ao estressor paraquat

    OpenAIRE

    Guarienti, Cíntia; Bertolin, Telma Elita; Costa, Jorge Alberto Vieira

    2010-01-01

    Em virtude de várias publicações terem mostrado a alta associação entre a geração de radicais livres e as doenças crônico-degenerativas, tem havido grande interesse por alimentos funcionais antioxidantes. O excesso de espécies reativas no organismo resulta em estresse oxidativo que provoca danos celulares e teciduais. A microalga Spirulina tem sido pesquisada em função de suas propriedades nutricionais e antioxidantes. O objetivo desse trabalho foi de avaliar a atividade antioxidante da mi...

  10. Information processing in the outer retina of fish

    NARCIS (Netherlands)

    Endeman, D.

    2017-01-01

    The retina translates light into neuronal activity. Thus, it renders visual information of the external environment. The retina can only send a limited amount of information to the brain within a given period. To use this amount optimally, light stimuli are strongly processed in the retina. This

  11. Direct transdifferentiation in the vertebrate retina.

    Science.gov (United States)

    Opas, M; Dziak, E

    1998-03-01

    Transdifferentiation is the process by which differentiated cells alter their identity to become other, distinct cell types. The conversion of neural retina into lens epithelium is one of the most spectacular examples of transdifferentiation. We show that the redirection of cell fate from neural retina to lens and subsequent transdifferentiation is independent of cell replication as it occurs in growth-arrested cell populations. Using DNA ratiometry of individual cells in these cultures we show that, indeed, individual amitotic cells do transdifferentiate. Hence, choice of fate in transdifferentiating cells does not rely on a "community effect" but instead can be categorized as a leadership effect> For lack of overt lens progenitors, and most importantly, for its mitotic independence, we conclude that lens colony formation in vitro does occur by direct transdifferentiation and not by clonal proliferation of progenitor cells.

  12. Thyroid Hormone Signaling in the Mouse Retina.

    Directory of Open Access Journals (Sweden)

    Patrick Arbogast

    Full Text Available Thyroid hormone is a crucial regulator of gene expression in the developing and adult retina. Here we sought to map sites of thyroid hormone signaling at the cellular level using the transgenic FINDT3 reporter mouse model in which neurons express β-galactosidase (β-gal under the control of a hybrid Gal4-TRα receptor when triiodothyronine (T3 and cofactors of thyroid receptor signaling are present. In the adult retina, nearly all neurons of the ganglion cell layer (GCL, ganglion cells and displaced amacrine cells showed strong β-gal labeling. In the inner nuclear layer (INL, a minority of glycineric and GABAergic amacrine cells showed β-gal labeling, whereas the majority of amacrine cells were unlabeled. At the level of amacrine types, β-gal labeling was found in a large proportion of the glycinergic AII amacrines, but only in a small proportion of the cholinergic/GABAergic 'starburst' amacrines. At postnatal day 10, there also was a high density of strongly β-gal-labeled neurons in the GCL, but only few amacrine cells were labeled in the INL. There was no labeling of bipolar cells, horizontal cells and Müller glia cells at both stages. Most surprisingly, the photoreceptor somata in the outer nuclear layer also showed no β-gal label, although thyroid hormone is known to control cone opsin expression. This is the first record of thyroid hormone signaling in the inner retina of an adult mammal. We hypothesize that T3 levels in photoreceptors are below the detection threshold of the reporter system. The topographical distribution of β-gal-positive cells in the GCL follows the overall neuron distribution in that layer, with more T3-signaling cells in the ventral than the dorsal half-retina.

  13. Expression and Localization of TRK-Fused Gene Products in the Rat Brain and Retina

    International Nuclear Information System (INIS)

    Maebayashi, Hisae; Takeuchi, Shigako; Masuda, Chiaki; Makino, Satoshi; Fukui, Kenji; Kimura, Hiroshi; Tooyama, Ikuo

    2012-01-01

    The TRK-fused gene (TFG in human, Tfg in rat) was originally identified in human papillary thyroid cancer as a chimeric form of the NTRK1 gene. It has been reported that the gene product (TFG) plays a role in regulating phosphotyrosine-specific phosphatase-1 activity. However, no information regarding the localization of Tfg in rat tissues is available. In this study, we investigated the expression of Tfg mRNA in normal rat tissues using reverse transcription-polymerase chain reaction (RT-PCR). We also produced an antibody against Tfg gene products and examined the localization of TFG in the rat brain and retina. The RT-PCR experiments demonstrated that two types of Tfg mRNA were expressed in rat tissues: the conventional form of Tfg (cTfg) and a novel variant form, retinal Tfg (rTfg). RT-PCR analyses demonstrated that cTfg was ubiquitously expressed in rat tissues, while rTfg was predominantly expressed in the brain and retina. Western blot analysis demonstrated two bands with molecular weights of about 30 kDa and 50 kDa in the rat brain. Immunohistochemistry indicated that TFG proteins were predominantly expressed by neurons in the brain. In the rat retina, intense TFG-immunoreactivity was detected in the layer of rods and cones and the outer plexiform layer

  14. Connecting the Retina to the Brain

    Directory of Open Access Journals (Sweden)

    Lynda Erskine

    2014-12-01

    Full Text Available The visual system is beautifully crafted to transmit information of the external world to visual processing and cognitive centers in the brain. For visual information to be relayed to the brain, a series of axon pathfinding events must take place to ensure that the axons of retinal ganglion cells, the only neuronal cell type in the retina that sends axons out of the retina, find their way out of the eye to connect with targets in the brain. In the past few decades, the power of molecular and genetic tools, including the generation of genetically manipulated mouse lines, have multiplied our knowledge about the molecular mechanisms involved in the sculpting of the visual system. Here, we review major advances in our understanding of the mechanisms controlling the differentiation of RGCs, guidance of their axons from the retina to the primary visual centers, and the refinement processes essential for the establishment of topographic maps and eye-specific axon segregation. Human disorders, such as albinism and achiasmia, that impair RGC axon growth and guidance and, thus, the establishment of a fully functioning visual system will also be discussed.

  15. The Neural Retina in Retinopathy of Prematurity

    Science.gov (United States)

    Hansen, Ronald M.; Moskowitz, Anne; Akula, James D.; Fulton, Anne B.

    2016-01-01

    Retinopathy of prematurity (ROP) is a neurovascular disease that affects prematurely born infants and is known to have significant long term effects on vision. We conducted the studies described herein not only to learn more about vision but also about the pathogenesis of ROP. The coincidence of ROP onset and rapid developmental elongation of the rod photoreceptor outer segments motivated us to consider the role of the rods in this disease. We used noninvasive electroretinographic (ERG), psychophysical, and retinal imaging procedures to study the function and structure of the neurosensory retina. Rod photoreceptor and post-receptor responses are significantly altered years after the preterm days during which ROP is an active disease. The alterations include persistent rod dysfunction, and evidence of compensatory remodeling of the post-receptor retina is found in ERG responses to full-field stimuli and in psychophysical thresholds that probe small retinal regions. In the central retina, both Mild and Severe ROP delay maturation of parafoveal scotopic thresholds and are associated with attenuation of cone mediated multifocal ERG responses, significant thickening of post-receptor retinal laminae, and dysmorphic cone photoreceptors. These results have implications for vision and control of eye growth and refractive development and suggest future research directions. These results also lead to a proposal for noninvasive management using light that may add to the currently invasive therapeutic armamentarium against ROP. PMID:27671171

  16. The mammalian retina as a clock

    Science.gov (United States)

    Tosini, Gianluca; Fukuhara, Chiaki

    2002-01-01

    Many physiological, cellular, and biochemical parameters in the retina of vertebrates show daily rhythms that, in many cases, also persist under constant conditions. This demonstrates that they are driven by a circadian pacemaker. The presence of an autonomous circadian clock in the retina of vertebrates was first demonstrated in Xenopus laevis and then, several years later, in mammals. In X. laevis and in chicken, the retinal circadian pacemaker has been localized in the photoreceptor layer, whereas in mammals, such information is not yet available. Recent advances in molecular techniques have led to the identification of a group of genes that are believed to constitute the molecular core of the circadian clock. These genes are expressed in the retina, although with a slightly different 24-h profile from that observed in the central circadian pacemaker. This result suggests that some difference (at the molecular level) may exist between the retinal clock and the clock located in the suprachiasmatic nuclei of hypothalamus. The present review will focus on the current knowledge of the retinal rhythmicity and the mechanisms responsible for its control.

  17. Fotocoagulação a laser em pacientes portadores de descolamento de retina regmatogênico periférico

    Directory of Open Access Journals (Sweden)

    Paulo Escarião

    2013-08-01

    Full Text Available OBJETIVO: Relatar uma série de casos de descolamento de retina sem envolvimento macular tratados com fotocoagulação a laser. MÉTODOS: Estudo tipo série de casos envolvendo 14 olhos de 12 pacientes com descolamento de retina regmatogênico sem envolvimento macular, retrospectivo, de intervenção. Olhos com procedimentos cirúrgicos prévios foram excluídos. A fotocoagulação a laser foi aplicada com três fileiras confluentes de spot de 300μm, posterior ao descolamento de retina, se extendendo até a ora serrata. A melhor acuidade visual corrigida pré e pós-operatória e a progressão do descolamento de retina foram registrados durante o estudo. RESULTADOS: Treze olhos necessitaram de apenas uma sessão de laser para conter o descolamento de retina. Apenas um olho necessitou de intervenção adicional por causa da evolução do descolamento de retina. Miopia foi encontrada em 7 olhos. Todos os pacientes mantiveram acuidade visual corrigida igual ou melhor que 20/30. CONCLUSÃO:Em casos bem selecionados, a fotocoagulação a laser pode ser considerada para o tratamento de descolamento de retina regmatogênico.

  18. Conduta na lesão dural intraoperatória em artrodese da coluna lombar Conducta en lesión de duramadre intraoperatoria en artrodesis de la columna lumbar Management of intraoperatory dural tear in lumbar spine arthrodesis

    OpenAIRE

    Fabiano de Mendonça Grandese; Clóvis Yamazato; Fábio Mastromauro de Oliveira; Iberê Ribeiro; José Olympio Catão Bastos Júnior; René Kusabara

    2010-01-01

    OBJETIVO: estudo retrospectivo de pacientes com lesão dural intraoperatória de cirurgia da coluna vertebral lombar, conduzido por meio de um protocolo independente da extensão da lesão, complicações associadas e resultados após seguimento mínimo de um ano. MÉTODOS: um total de 10 pacientes com durotomia acidental em cirurgias de descompressão e artrodese da coluna vertebral lombar, no período de Janeiro de 2007 a Janeiro de 2009, para tratamento de doença degenerativa, tiveram seus prontuário...

  19. Proteomic interactions in the mouse vitreous-retina complex.

    Directory of Open Access Journals (Sweden)

    Jessica M Skeie

    Full Text Available Human vitreoretinal diseases are due to presumed abnormal mechanical interactions between the vitreous and retina, and translational models are limited. This study determined whether nonstructural proteins and potential retinal biomarkers were expressed by the normal mouse vitreous and retina.Vitreous and retina samples from mice were collected by evisceration and analyzed by liquid chromatography-tandem mass spectrometry. Identified proteins were further analyzed for differential expression and functional interactions using bioinformatic software.We identified 1,680 unique proteins in the retina and 675 unique proteins in the vitreous. Unbiased clustering identified protein pathways that distinguish retina from vitreous including oxidative phosphorylation and neurofilament cytoskeletal remodeling, whereas the vitreous expressed oxidative stress and innate immunology pathways. Some intracellular protein pathways were found in both retina and vitreous, such as glycolysis and gluconeogenesis and neuronal signaling, suggesting proteins might be shuttled between the retina and vitreous. We also identified human disease biomarkers represented in the mouse vitreous and retina, including carbonic anhydrase-2 and 3, crystallins, macrophage inhibitory factor, glutathione peroxidase, peroxiredoxins, S100 precursors, and von Willebrand factor.Our analysis suggests the vitreous expresses nonstructural proteins that functionally interact with the retina to manage oxidative stress, immune reactions, and intracellular proteins may be exchanged between the retina and vitreous. This novel proteomic dataset can be used for investigating human vitreoretinopathies in mouse models. Validation of vitreoretinal biomarkers for human ocular diseases will provide a critical tool for diagnostics and an avenue for therapeutics.

  20. Proteomic interactions in the mouse vitreous-retina complex.

    Science.gov (United States)

    Skeie, Jessica M; Mahajan, Vinit B

    2013-01-01

    Human vitreoretinal diseases are due to presumed abnormal mechanical interactions between the vitreous and retina, and translational models are limited. This study determined whether nonstructural proteins and potential retinal biomarkers were expressed by the normal mouse vitreous and retina. Vitreous and retina samples from mice were collected by evisceration and analyzed by liquid chromatography-tandem mass spectrometry. Identified proteins were further analyzed for differential expression and functional interactions using bioinformatic software. We identified 1,680 unique proteins in the retina and 675 unique proteins in the vitreous. Unbiased clustering identified protein pathways that distinguish retina from vitreous including oxidative phosphorylation and neurofilament cytoskeletal remodeling, whereas the vitreous expressed oxidative stress and innate immunology pathways. Some intracellular protein pathways were found in both retina and vitreous, such as glycolysis and gluconeogenesis and neuronal signaling, suggesting proteins might be shuttled between the retina and vitreous. We also identified human disease biomarkers represented in the mouse vitreous and retina, including carbonic anhydrase-2 and 3, crystallins, macrophage inhibitory factor, glutathione peroxidase, peroxiredoxins, S100 precursors, and von Willebrand factor. Our analysis suggests the vitreous expresses nonstructural proteins that functionally interact with the retina to manage oxidative stress, immune reactions, and intracellular proteins may be exchanged between the retina and vitreous. This novel proteomic dataset can be used for investigating human vitreoretinopathies in mouse models. Validation of vitreoretinal biomarkers for human ocular diseases will provide a critical tool for diagnostics and an avenue for therapeutics.

  1. Stem-cell treatment in disc degeneration: What is the evidence? Células madre en el tratamiento de degeneración de disco: ¿Cual es la evidencia? Células tronco no tratamento de doença degenerativa discal: Qual é a evidência?

    Directory of Open Access Journals (Sweden)

    Manuela Peletti-Figueiró

    2013-01-01

    inflamatorios de la IVD degenerado. Además, estudios experimentales demostraron que las MSC se mantuvieron viables cuando inyectadas en el IVD y que eran capaces de regenerarse parcialmente del IVD degenerado y su estructura. Los pocos estudios clínicos presentes en la literatura presentan resultados divergentes. El uso de MSC se está estudiando ampliamente y muestra resultados prometedores en el tratamiento de la DDD. Aunque se hayan logrado muchos avances en estudios in vitro y experimentales, aún faltan estudios clínicos para comprobar el papel de las MSC en el manejo de la DDD.Revisar o potencial papel das células-tronco para o tratamento de doença degenerativa do disco intervertebral (IVD. Foi realizada uma revisão dos trabalhos da base de dados Medline em relação a células-tronco e doença degenerativa discal (DDD. Para fins de discussão dos dados, os trabalhos foram divididos em: revisão, in vitro, experimentais e clínicos. Os tratamentos disponíveis atualmente focam basicamente na redução dos sintomas, e não na reversão do processo degenerativo do DIV. O uso de células-tronco mesenquimais (CTM vem sendo proposto como uma opção de tratamento para DDD. Estudos in vitro demonstraram que as CTM são capazes de se diferenciarem em células do NP e que as CTM também diminuem os níveis inflamatórios do DIV degenerado. Além disso, estudos experimentais demonstraram que as CTM permaneciam viáveis quando injetadas no DIV e que eram capazes de regenerar parcialmente do DIV degenerado e sua estrutura. Os poucos estudos clínicos presentes na literatura apresentam resultados divergentes. O uso de CTM esta sendo amplamente estudado e mostra resultados promissores para o tratamento da DDD. Embora muitos avanços venham sendo alcançados em estudos in vitro e experimentais, ainda faltam estudos clínicos para comprovar o papel das CTM no manejo da DDD.

  2. Insulin-like activity in the retina

    International Nuclear Information System (INIS)

    Das, A.

    1986-01-01

    A number of studies have recently demonstrated that insulin or a homologous peptide may be synthesized outside the pancreas also. The present study was designed to investigate whether insulin-like activity exists in the retina, and if it exists, whether it is due to local synthesis of insulin or a similar peptide in the retina. To determine whether the insulin-like immunoreactivity in retinal glial cells is due to binding and uptake or local synthesis of insulin, a combined approach of immunocytochemistry and in situ DNA-RNA hybridization techniques was used on cultured rat retinal glial cells. Insulin-like immunoreactivity was demonstrated in the cytoplasma of these cells. In situ hybridization studies using labeled rat insulin cDNA indicated that these cells contain the mRNA necessary for de novo synthesis of insulin or a closely homologous peptide. Since human retinal cells have, as yet, not been conveniently grown in culture, an ocular tumor cell line, human Y79 retinoblastoma was used as a model to extend these investigations. The presence of insulin-like immunoreactivity as well as insulin-specific mRNA was demonstrated in this cell line. Light microscopic autoradiography following incubation of isolated rat retinal cells with 125 I-insulin showed the presence of insulin binding sites on the photoreceptors and amarcine cells. On the basis of these observations that rat retina glial cells, including Muller cells are sites of synthesis of insulin or a similar peptide, a model for the pathogenesis of dabetic retinopathy is proposed

  3. Immunohistochemical Localization of an Isoform of TRK-Fused Gene-Like Protein in the Rat Retina

    International Nuclear Information System (INIS)

    Masuda, Chiaki; Takeuchi, Shigeko; Bisem, Naomi J.; Vincent, Steven R.; Tooyama, Ikuo

    2014-01-01

    The TRK-fused gene (TFG) was originally identified in chromosome translocation events, creating a pair of oncogenes in some cancers, and was recently demonstrated as the causal gene of hereditary motor and sensory neuropathy with proximal dominant involvement. Recently, we cloned an alternative splicing variant of Tfg from a cDNA library of the rat retina, tentatively naming it retinal Tfg (rTfg). Although the common form of Tfg is ubiquitously expressed in most rat tissues, rTfg expression is localized to the central nervous system. In this study, we produced an antibody against an rTFG-specific amino acid sequence and used it to examine the localization of rTFG-like protein in the rat retina by immunohistochemistry and Western blots. Western blot analysis showed that the antibody detected a single band of 24 kDa in the rat retina. When we examined rTFG recombinant protein, the antibody detected two bands of about 42 kDa and 24 kDa. The results suggest that the 24 kDa rTFG-like protein is a fragment of rTFG. In our immunohistochemical studies of the rat retina, rTFG-like immunoreactivity was observed in all calbindin D-28K-positive horizontal cells and in some syntaxin 1-positive amacrine cells (ACs). In addition, the rTFG-like immunopositive ACs were actually glycine transporter 1-positive glycinergic or glutamate decarboxylase-positive GABAergic ACs. Our findings indicate that this novel 24 kDa rTFG-like protein may play a specific role in retinal inhibitory interneurons

  4. Lactate Transport and Receptor Actions in Retina

    DEFF Research Database (Denmark)

    Kolko, Miriam; Vosborg, Fia; Henriksen, Jens Ulrik Lütken

    2016-01-01

    known as HCAR1, may contribute importantly to the control of retinal cell functions in health and disease. GPR81, a G-protein coupled receptor, is known to downregulate cAMP both in adipose and nervous tissue. The receptor also acts through other down-stream mechanisms to control functions......In retina, like in brain, lactate equilibrates across cell membranes via monocarboxylate transporters and in the extracellular space by diffusion, forming a basis for the action of lactate as a transmitter of metabolic signals. In the present paper, we argue that the lactate receptor GPR81, also...

  5. Modeling laser damage to the retina

    Science.gov (United States)

    Clark, Clifton D.

    This dissertation presents recent progress in several areas related to modeling laser damage to the retina. In Chapter 3, we consider the consequences of using the Arrhenius damage model to predict the damage thresholds of multiple pulse, or repetitive pulse, exposures. We have identified a few fundamental trends associated with the multiple pulse damage predictions made by the Arrhenius model. These trends differ from what would be expected by non-thermal mechanisms, and could prove useful in differentiating thermal and non-thermal damage. Chapter 4 presents a new rate equation damage model hypothesized to describe photochemical damage. The model adds a temperature dependent term to the simple rate equation implied by the principle of reciprocity that is characteristic of photochemical damage thresholds. A recent damage threshold study, conducted in-vitro, has revealed a very sharp transition between thermal and photochemical damage threshold trends. For the wavelength used in the experiment (413 nm), thermal damage thresholds were observed at exposure levels that were twice the expected photochemical damage threshold, based on the traditional understanding of photochemical damage. Our model accounts for this observed trend by introducing a temperature dependent quenching, or repair, rate to the photochemical damage rate. For long exposures that give a very small temperature rise, the model reduces to the principle of reciprocity. Near the transition region between thermal and photochemical damage, the model allows the damage threshold to be set by thermal mechanisms, even at exposure above the reciprocity exposure. In Chapter 5, we describe a retina damage model that includes thermal lensing in the eye by coupling beam propagation and heat transfer models together. Thermal lensing has recently been suggested as a contributing factor to the large increase in measured retinal damage thresholds in the near infrared. The transmission of the vitreous decreases

  6. Glycinergic pathways in the goldfish retina

    International Nuclear Information System (INIS)

    Marc, R.E.; Lam, D.M.

    1981-01-01

    Autoradiographic localization of high affinity [3H]glycine uptake in the retina of the goldfish has been used to study some anatomical and physiological properties of potentially glycinergic neurons. There are two classes of retinal cells exhibiting high affinity glycine uptake: Aa amacrine cells and I2 interplexiform cells. Aa amacrine cells constitute about 20% of the somas in the amacrine cell layer and send their dendrites to the middle of the inner plexiform layer. There they are both pre- and postsynaptic primarily to other amacrine cells. Photic modulation of glycine uptake indicates that they are probably red-hyperpolarizing/green-depolarizing neurons. I2 interplexiform cells are a newly discovered type of interplexiform cell; in the outer plexiform layer, they receive direct synaptic input from the somas of red-dominated GABAergic H1 horizontal cells and are apparently presynaptic to dendrites of unidentified types of horizontal cells. The connections of I2 interplexiform cells have not been successfully characterized in the inner plexiform layer. These findings extend our knowledge of neurochemically specific pathways in the cyprinid retina and indicate that glycine, like GABA, is a neurotransmitter primarily involved with circuits coding ''red'' information

  7. Avaliação das funções executivas em idosos acometidos por doenças crónico-degenerativas

    Directory of Open Access Journals (Sweden)

    Ivone Lúcia Brito

    2012-01-01

    Full Text Available Los avances en las condiciones de salud ha facilitado el aumento de la longevidad y por lo tanto una mayor esperanza de vida. Esta investigación se realizó con el objetivo de verificar la existencia de déficits en el desempeño de las funciones ejecutivas en pacientes ancianos con enfermedades crónicas a través de la prueba de clasificación de tarjetas de Wisconsin e investigar patologías asociadas (depresión y ansiedad y sus implicaciones en la vida en los ancianos. Se estudiaron 30 ancianos hombres y mujeres, mayores de 60 años, diagnosticados con enfermedades crónicas degenerativas (Diabetes Mellitus y la hipertensión. El diseño fue un estudio cuantitativo y transversal, con los instrumentos: hoja de datos socio-demográficos, prueba Wisconsin Card (WCST, inventario de depresión de Beck (BDI-I, inventario de ansiedad de Beck (BAI y la escala de depresión geriátrica (GDS. Los res uItad os in dican que los ancia nos ha n mostrad o dificultades en la realización de las tareas como descriptores de la WCST. En correlaciones altamente significativas entre la puntuación total de la GDS BAI (r = 0.667, P < 0,001, lo que significa que, en la medida en que los síntomas de ansiedad aumentan también aumenta los síntomas depresivos.

  8. Impact of MCT1 Haploinsufficiency on the Mouse Retina

    KAUST Repository

    Peachey, Neal S.

    2018-05-02

    The monocarboxylate transporter 1 (MCT1) is highly expressed in the outer retina, suggesting that it plays a critical role in photoreceptors. We examined MCT1+/− heterozygotes, which express half of the normal complement of MCT1. The MCT1+/− retina developed normally and retained normal function, indicating that MCT1 is expressed at sufficient levels to support outer retinal metabolism.

  9. Imagen de retina de campo ultra-amplio

    Directory of Open Access Journals (Sweden)

    Gerardo García-Aguirre

    2017-11-01

    Conclusión: Las imágenes de campo ultra-amplio han revolucionado la forma en la que estudiamos y entendemos la enfermedad de la retina. A medida que la tecnología para obtenerlas se haga más accesible, formará parte del armamentario de rutina para estudiar las enfermedades de la retina.

  10. Impact of MCT1 Haploinsufficiency on the Mouse Retina

    KAUST Repository

    Peachey, Neal S.; Yu, Minzhong; Han, John Y. S.; Lengacher, Sylvain; Magistretti, Pierre J.; Pellerin, Luc; Philp, Nancy J.

    2018-01-01

    The monocarboxylate transporter 1 (MCT1) is highly expressed in the outer retina, suggesting that it plays a critical role in photoreceptors. We examined MCT1+/− heterozygotes, which express half of the normal complement of MCT1. The MCT1+/− retina developed normally and retained normal function, indicating that MCT1 is expressed at sufficient levels to support outer retinal metabolism.

  11. Adaptive optics imaging of the retina

    Directory of Open Access Journals (Sweden)

    Rajani Battu

    2014-01-01

    Full Text Available Adaptive optics is a relatively new tool that is available to ophthalmologists for study of cellular level details. In addition to the axial resolution provided by the spectral-domain optical coherence tomography, adaptive optics provides an excellent lateral resolution, enabling visualization of the photoreceptors, blood vessels and details of the optic nerve head. We attempt a mini review of the current role of adaptive optics in retinal imaging. PubMed search was performed with key words Adaptive optics OR Retina OR Retinal imaging. Conference abstracts were searched from the Association for Research in Vision and Ophthalmology (ARVO and American Academy of Ophthalmology (AAO meetings. In total, 261 relevant publications and 389 conference abstracts were identified.

  12. Topography of ganglion cell production in the cat's retina

    International Nuclear Information System (INIS)

    Walsh, C.; Polley, E.H.

    1985-01-01

    The ganglion cells of the cat's retina form several classes distinguishable in terms of soma size, axon diameter, dendritic morphology, physiological properties, and central connections. Labeling with [ 3 H]thymidine shows that the ganglion cells which survive in the adult are produced as several temporally shifted, overlapping waves: medium-sized cells are produced before large cells, whereas the smallest ganglion cells are produced throughout the period of ganglion cell generation. Large cells and medium-sized cells show the same distinctive pattern of production, forming rough spirals around the area centralis. The oldest cells tend to lie superior and nasal to the area centralis, whereas cells in the inferior nasal retina and inferior temporal retina are, in general, progressively younger. Within each retinal quadrant, cells nearer the area centralis tend to be older than cells in the periphery, but there is substantial overlap. The retinal raphe divides the superior temporal quadrant into two zones with different patterns of cell addition. Superior temporal retina near the vertical meridian adds cells only slightly later than superior nasal retina, whereas superior temporal retina near the horizontal meridian adds cells very late, contemporaneously with inferior temporal retina. The broader wave of production of smaller ganglion cells seems to follow this same spiral pattern at its beginning and end. The presence of the area centralis as a nodal point about which ganglion cell production in the retinal quadrants pivots suggests that the area centralis is already an important retinal landmark even at the earliest stages of retinal development

  13. Neurotransmitter-Regulated Regeneration in the Zebrafish Retina

    Directory of Open Access Journals (Sweden)

    Mahesh B. Rao

    2017-04-01

    Full Text Available Summary: Current efforts to repair damaged or diseased mammalian retinas are inefficient and largely incapable of fully restoring vision. Conversely, the zebrafish retina is capable of spontaneous regeneration upon damage using Müller glia (MG-derived progenitors. Understanding how zebrafish MG initiate regeneration may help develop new treatments that prompt mammalian retinas to regenerate. We show that inhibition of γ-aminobutyric acid (GABA signaling facilitates initiation of MG proliferation. GABA levels decrease following damage, and MG are positioned to detect decreased ambient levels and undergo dedifferentiation. Using pharmacological and genetic approaches, we demonstrate that GABAA receptor inhibition stimulates regeneration in undamaged retinas while activation inhibits regeneration in damaged retinas. : Unlike mammals, zebrafish regenerate following retina damage from a resident adult stem cell (Müller glia. Dissecting the mechanisms that zebrafish use could lead to new therapeutic targets to treat retinal diseases. Patton and colleagues have discovered a mechanism by which decreased GABA levels are sensed by Müller glia to initiate a regenerative response. Keywords: zebrafish, retina, regeneration, Müller glia, GABA

  14. Proposição de uma reserva anatomofuncional, no canal raquidiano, como fator interferente na fisiopatologia das lombalgias e lombociatalgias mecânico-degenerativas

    Directory of Open Access Journals (Sweden)

    Cecin H.A.

    1997-01-01

    Full Text Available OBJETIVO. Testar a hipótese de uma reserva anatomofuncional no canal raquidiano que explique as elevadas prevalências de alterações radiológicas na coluna lombar de indivíduos assintomáticos, as diferentes formas de apresentação clínica das lombalgias e lombociatalgias mecânico-degenerativas e as discrepâncias na sua prevalência. CASUÍSTICA E MÉTODOS. Dois grupos de pessoas foram submetidos à tomografia axial computadorizada. Um era de 27 pacientes com lombalgia e/ou lombociatalgia. O outro, de controles pareados, era de 27 indivíduos assintomáticos. Em ambos os grupos, foram medidas as áreas do canal ósseo, do saco dural, a distância interfacetária e a profundidade dos recessos laterais. RESULTADOS. Os assintomáticos tinham canais raquidianos mais amplos que o de pacientes agudos e crônicos. As variáveis, cujas comparações foram responsáveis por essas diferenças estatisticamente significantes nos crônicos, foram as áreas do canal ósseo em L3-L4, L4-L5, as áreas do saco dural em L4-L5, L5-S1 e a profundidade dos recessos laterais em L4-L5; e nos agudos: a área do canal ósseo em L3-L4, L4-L5, L5-S1, área do saco dural em L4-L5, L5-S1, o diâmetro sagital em L5-S1 e a profundidade do recesso lateral direito em L4-L5. CONCLUSÕES. As alterações radiológicas e ausência de sintomas no grupo-controle foram atribuídas a uma maior reserva anatomofuncional no canal raquidiano; a existência de casos agudos e crônicos, a uma reserva menor. Esta reserva, maior ou menor, seria um "fator segurança" que se distribuiria diferencialmente em assintomáticos, agudos e crônicos, e seria o elemento capaz de influenciar a prevalência, a presença ou ausência de dor lombar em indivíduos com alterações radiológicas.

  15. Vitreous in lattice degeneration of retina.

    Science.gov (United States)

    Foos, R Y; Simons, K B

    1984-05-01

    A localized pocket of missing vitreous invariably overlies lattice degeneration of the retina. Subjects with lattice also have a higher rate of rhegmatogenous retinal detachment, which is usually a complication of retinal tears. The latter are in turn a result of alterations in the central vitreous--that is, synchysis senilis leading to posterior vitreous detachment. In order to determine if there is either an association or a deleterious interaction between the local and central lesions of the vitreous in eyes with lattice, a comparison was made in autopsy eyes with and without lattice the degree of synchysis and rate of vitreous detachment. Results show no association between the local and central vitreous lesions, indicating that a higher rate of vitreous detachment is not the basis for the higher rate of retinal detachment in eyes with lattice. Also, there was no suggestion of deleterious interaction between the local and central vitreous lesions, either through vitreodonesis as a basis for precocious vitreous detachment, or through a greater degree of synchysis as a basis for interconnection of local and central lacunae (which could extend the localized retinal detachment in eyes with holes in lattice degeneration).

  16. Simulating the Effects of Laser Damage to the Retina

    National Research Council Canada - National Science Library

    2001-01-01

    This Phase II SBIR brought vision and signal processing researchers from the Air Force, academia and the public sector together to develop a visualization tool for modeling laser damage to the retina...

  17. Simple Experiments on the Physics of Vision: The Retina

    Science.gov (United States)

    Cortel, Adolf

    2005-01-01

    Many simple experiments can be performed in the classroom to explore the physics of vision. Students can learn of the two types of receptive cells (rods and cones), their distribution on the retina and the existence of the blind spot.

  18. Avaliação do risco de dano da vértebra lombar após artroplastia

    OpenAIRE

    Duarte, Ana Rita Pereira

    2015-01-01

    A substituição do disco intervertebral lombar tem sido considerada uma alternativa cirúrgica ao tratamento da doença degenerativa do disco lombar. Comparada com a fusão lombar, a artroplastia discal preserva a mobilidade entre segmentos e decresce potencialmente os problemas nos discos adjacentes a termo. Nas avaliações de longo prazo, a vantagem teórica de redução de problemas nos discos adjacentes não tem sido completamente evidenciada. Diferente dos sistemas de artrodese de fusão, que trab...

  19. Monte Carlo simulation of zinc protoporphyrin fluorescence in the retina

    Science.gov (United States)

    Chen, Xiaoyan; Lane, Stephen

    2010-02-01

    We have used Monte Carlo simulation of autofluorescence in the retina to determine that noninvasive detection of nutritional iron deficiency is possible. Nutritional iron deficiency (which leads to iron deficiency anemia) affects more than 2 billion people worldwide, and there is an urgent need for a simple, noninvasive diagnostic test. Zinc protoporphyrin (ZPP) is a fluorescent compound that accumulates in red blood cells and is used as a biomarker for nutritional iron deficiency. We developed a computational model of the eye, using parameters that were identified either by literature search, or by direct experimental measurement to test the possibility of detecting ZPP non-invasively in retina. By incorporating fluorescence into Steven Jacques' original code for multi-layered tissue, we performed Monte Carlo simulation of fluorescence in the retina and determined that if the beam is not focused on a blood vessel in a neural retina layer or if part of light is hitting the vessel, ZPP fluorescence will be 10-200 times higher than background lipofuscin fluorescence coming from the retinal pigment epithelium (RPE) layer directly below. In addition we found that if the light can be focused entirely onto a blood vessel in the neural retina layer, the fluorescence signal comes only from ZPP. The fluorescence from layers below in this second situation does not contribute to the signal. Therefore, the possibility that a device could potentially be built and detect ZPP fluorescence in retina looks very promising.

  20. Fundus autofluorescence and the bisretinoids of retina.

    Science.gov (United States)

    Sparrow, Janet R; Wu, Yalin; Nagasaki, Takayuki; Yoon, Kee Dong; Yamamoto, Kazunori; Zhou, Jilin

    2010-11-01

    Imaging of the human fundus of the eye with excitation wavelengths in the visible spectrum reveals a natural autofluorescence, that in a healthy retina originates primarily from the bisretinoids that constitute the lipofuscin of retinal pigment epithelial (RPE) cells. Since the intensity and distribution of fundus autofluorescence is altered in the presence of retinal disease, we have examined the fluorescence properties of the retinal bisretinoids with a view to aiding clinical interpretations. As is also observed for fundus autofluorescence, fluorescence emission from RPE lipofuscin was generated with a wide range of exciting wavelengths; with increasing excitation wavelength, the emission maximum shifted towards longer wavelengths and spectral width was decreased. These features are consistent with fluorescence generation from a mixture of compounds. While the bisretinoids that constitute RPE lipofuscin all fluoresced with maxima that were centered around 600 nm, fluorescence intensities varied when excited at 488 nm, the excitation wavelength utilized for fundus autofuorescence imaging. For instance the fluorescence efficiency of the bisretinoid A2-dihydropyridine-phosphatidylethanolamine (A2-DHP-PE) was greater than A2E and relative to both of the latter, all-trans-retinal dimer-phosphatidylethanolamine was weakly fluorescent. On the other hand, certain photooxidized forms of the bisretinoids present in both RPE and photoreceptor cells were more strongly fluorescent than the parent compound. We also sought to evaluate whether diffuse puncta of autofluorescence observed in some retinal disorders of monogenic origin are attributable to retinoid accumulation. However, two retinoids of the visual cycle, all-trans-retinyl ester and all-trans-retinal, did not exhibit fluorescence at 488 nm excitation.

  1. Tomografia de coerência óptica na commotio retinae: relato de caso Optical coherence tomography imaging in commotio retinae: case report

    Directory of Open Access Journals (Sweden)

    Celso Morita

    2009-08-01

    Full Text Available O objetivo deste relato é correlacionar achados à tomografia de coerência óptica e prognóstico visual de pacientes com commotio retina e de gravidades diferentes. Dois pacientes do sexo masculino, de 20 e 23 anos com baixa visual unilateral após trauma ocular contuso atribuível a edema de Berlin foram avaliados pela retinografia e tomografia de coerência óptica. A acuidade visual no olho afetado era de 20/25 no primeiro paciente e conta dedos a 2 metros no segundo. O exame oftalmológico revelou uveíte traumática e, na fundoscopia, evidenciaram-se opacificação retiniana moderada no primeiro caso e grave no segundo. A tomografia de coerência óptica confirmou discreta diminuição da depressão foveal no primeiro caso e desorganização das camadas retinianas no segundo. Houve resolução anatômica e funcional completa a tomografia de coerência óptica no primeiro paciente, enquanto o segundo evoluiu com baixa visual permanente e desorganização da arquitetura retiniana. A tomografia de coerência óptica é um exame complementar útil na avaliação do trauma retiniano, ajudando a entender sua fisiopatologia e predizer prognóstico a partir da análise anatômica da região acometida.The purpose of this case report was to correlate optical coherence tomography findings and visual outcomes of patients with different degrees of commotio retinae. A 20-year-old male and a 23-year-old male that presented with decreased vision due to Berlin's edema after blunt ocular trauma were evaluated by optical coherence tomography and retinography. The visual acuity in the affected eye was 20/25 in the first patient and counting fingers in the second one. The ophthalmic examination showed traumatic uveitis and fundoscopy revealed mild retinal opacification in the first case and severe opacification in the latter. The optical coherence tomography confirmed the reduction of foveal depression on the first case and the disarrangement of all retinal

  2. Towards metabolic mapping of the human retina.

    Science.gov (United States)

    Schweitzer, D; Schenke, S; Hammer, M; Schweitzer, F; Jentsch, S; Birckner, E; Becker, W; Bergmann, A

    2007-05-01

    = 190 ps) originates from the retinal pigment epithelium and the second lifetime (t2 = 1,000 ps) from the neural retina. The lifetime t3 approximately 5.5 ns might be influenced by the long decay of the fluorescence in the crystalline lens. In vitro analysis of the spectral properties of expected fluorophores under the condition of the living eye lightens the interpretation of in vivo measurements. Taking into account the transmission of the ocular media, the excitation of NADH is unlikely at the fundus. Copyright 2007 Wiley-Liss, Inc.

  3. Retina neural circuitry seen with particle detector technology

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Using particle physics techniques, high energy physics researchers have recently provided new insight into neural circuits inside the retina. After uncovering a new type of retinal cell and mapping how the retina deals with colours, the team from Santa Cruz (US), Krakow and Glasgow is now turning its attention to more complex issues such as how the retina gets wired up and how the brain deals with the signals it receives from the retina. All this using technology derived from high-density, multistrip silicon detectors…   Seen from the point of view of a particle physicist, eyes are image detectors that can gather many different types of data: light and dark, different colours, motion, etc. In particular, the retina, a thin tissue that lines the back of the eye, is a biological pixel detector that detects light and converts it to electrical signals that travel through the optic nerve to the brain. Neurobiologists know that many different cell types are involved in these processes, but they...

  4. [Lattice degeneration of the peripheral retina: ultrastructural study].

    Science.gov (United States)

    Bec, P; Malecaze, F; Arne, J L; Mathis, A

    1985-01-01

    The ultrastructural study of a case of snail track degeneration shows the presence of lipid inclusions in both the glial and the macrophage cells in every layer of the retina, and the existence of intraretinal fibers different from collagen fibers appearing to be glial filaments similar to those found in astrocytic gliomes and to the Rosenthal fibers observed in senile nervous cells. Other features were thinning of the retina and absence of blood vessels in the retina. There are no abnormalities of the vitreo-retinal juncture. All the lesions are in agreement with those observed by Daicker [Ophthalmologica, Basel 165: 360-365, 1972; Klin. Mbl. Augenheilk. 172: 581-583, 1978] with some differences, however. They are different from those found in lattice degeneration. They show that snail track degeneration is a specific form of peripheral retinal degeneration which is quite different from lattice degeneration and must not be considered similar.

  5. Repercussões electrocardiográficas em canídeos com doença mixomatosa da válvula mitral avaliados ecocardiograficamente

    OpenAIRE

    Baptista, Sandra Isabel Pereira

    2013-01-01

    Dissertação de Mestrado Integrado em Medicina Veterinária A doença mixomatosa degenerativa da válvula mitral (DMVM) é a doença cardiovascular adquirida mais comum em cães. A sobrecarga de volume consequente à doença promove remodelação cardíaca com dilatação do átrio esquerdo (AE) e hipertrofia excêntrica (HE) do ventrículo esquerdo (VE). O objetivo deste estudo passou por avaliar as repercussões dessa remodelação no eletrocardiograma (ECG). Para tal foram avaliados ecocardiograficament...

  6. Efficacy and safety of dynamic stabilization for patients with degenerative disc, spinal stenosis and low back pain: a systematic review of randomized controlled clinical trials Eficacia y seguridad de los sistemas de estabilización dinámica en pacientes con enfermedad discal degenerativa, estenosis de canal y lumbalgia: revisión sistemática de estudios clínicos randomizados Eficácia e segurança dos sistemas de estabilização dinâmica em pacientes com doença discal degenerativa, estenose de canal e lombalgia: revisão sistemática de estudos clínicos randomizados

    Directory of Open Access Journals (Sweden)

    Gustavo Carriço de Oliveira

    2010-09-01

    para cada tipo de estudio. REVISIÓN DE LITERATURA: publicaciones recientes han aumentado el debate acerca del papel de los sistemas de estabilización dinámica en el tratamiento del dolor lumbar crónico asociado a la degeneración discal lumbar y estenosis de canal lumbar. Fue conducida una revisión sistemática de ensayos randomizados a través de la estrategia de búsqueda apurada y selección con criterios aplicados para cada tipo de estudio. MÉTODOS: una revisión de la literatura a través de las siguientes fuentes fue realizada: Cochrane Central Register of Controlled Trials, MEDLINE, Excerpta Medica database (EMBASE y Literatura latino-Americana y del Caribe en Ciencias de la Salud (LILACS. La revisión pudo identificar los estudios clínicos randomizados o no. No hubo restricción de idioma y la fecha límite de búsqueda fue 31 de noviembre de 2008. RESULTADOS: un ensayo controlado randomizado, que llenó los criterios de inclusión descritos encima, fue incluido en esto estudio. CONCLUSIÓN: los datos incluidos en esta revisión muestran que el uso de los sistemas de estabilización sin fusión son una alternativa aceptable para el tratamiento de pacientes con estenosis de canal lumbar y enfermedad degenerativa discal en pacientes bien seleccionados. Esta revisión destaca la necesidad de investigación continuada sobre el uso de los sistemas de estabilización dinámica para tratamiento de las patologías de la columna vertebral. Existe una necesidad urgente para la conducción de ensayos clínicos randomizados. La eficacia a largo plazo debe de ser evaluada.DESENHO DE ESTUDO: Revisão sistemática da literatura. OBJETIVO: Realizar revisão sistemática da literatura para organizar, avaliar e selecionar evidências a respeito do uso dos sistemas de estabilização dinâmica, sua eficácia e segurança no tratamento da doença degenerativa discal, estenose do canal lombar e dor lombar. REVISÃO DE LITERATURA: Publicações recentes têm aumentado o

  7. Image Signal Transfer Method in Artificial Retina using Laser

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, I.Y.; Lee, B.H.; Kim, S.J. [Seoul National University, Seoul (Korea)

    2002-05-01

    Recently, the research on artificial retina for the blind is active. In this paper a new optical link method for the retinal prosthesis is proposed. Laser diode system was chosen to transfer image into the eye in this project and the new optical system was designed and evaluated. The use of laser diode array in artificial retina system makes system simple for lack of signal processing part inside of the eyeball. Designed optical system is enough to focus laser diode array on photodiode array in 20X20 application. (author). 11 refs., 7 figs., 2 tabs.

  8. Retina-like sensor image coordinates transformation and display

    Science.gov (United States)

    Cao, Fengmei; Cao, Nan; Bai, Tingzhu; Song, Shengyu

    2015-03-01

    For a new kind of retina-like senor camera, the image acquisition, coordinates transformation and interpolation need to be realized. Both of the coordinates transformation and interpolation are computed in polar coordinate due to the sensor's particular pixels distribution. The image interpolation is based on sub-pixel interpolation and its relative weights are got in polar coordinates. The hardware platform is composed of retina-like senor camera, image grabber and PC. Combined the MIL and OpenCV library, the software program is composed in VC++ on VS 2010. Experience results show that the system can realizes the real-time image acquisition, coordinate transformation and interpolation.

  9. EVALUATION OF INHOMOGENEITIES IN HISTOLOGICAL STRUCTURES (CARTILAGE, RETINA

    Directory of Open Access Journals (Sweden)

    Lutz Muche

    2011-05-01

    Full Text Available This paper investigates histological tissues by means of image analysis and spatial statistics. For the quantification of cell frequencies and accumulations two statistical characteristics, intensity function and cluster density, are suggested. The samples are histological sections of human articular cartilage and human retina considered in view of changes during the ageing process. The articular cartilage is characterized by continuous changes of both functions, the cell intensity as well as the clusterization. In contrast, the retina is a trilaminar structure formed in the early embryonic stage without changes by ageing.

  10. Avaliação da reprodutibilidade das medidas da camada de fibras nervosas retiniana e da cabeça do nervo óptico pela tomografia de coerência óptica

    Directory of Open Access Journals (Sweden)

    Ricardo Rau

    2012-10-01

    Full Text Available OBJETIVO: Determinar a reprodutibilidade da espessura da camada de fibras nervosas da retina peripapilar e dos parâmetros da cabeça do nervo óptico em olhos normais, utilizando a tomografia de coerência óptica de domínio espectral (SD-OCT. MÉTODOS: Trinta e quatro olhos de 34 indivíduos saudáveis foram incluídos no estudo. O protocolo do cubo do disco óptico 200x200 do OCT Cirrus foi utilizado para gerar 3 imagens de cada olho para avaliar a reprodutibilidade. O coeficiente de correlação intraclasse (ICC foi calculado para as medidas da espessura da camada de fibras nervosas da retina e da cabeça do nervo óptico. RESULTADOS: A correlação foi excelente para todas as medidas da espessura da camada de fibras nervosas da retina (ICC entre 0,87 e 0,98. O mesmo ocorreu com os parâmetros da cabeça do nervo óptico que, com exceção da razão E/D vertical (ICC 0,56, apresentou ICC entre 0,83 e 0,99. CONCLUSÃO: As medidas de espessura da camada de fibras nervosas da retina peripapilar e os parâmetros da cabeça no nervo óptico demonstraram uma excelente reprodutibilidade com o OCT Cirrus, indicando que este aparelho poderá ser uma ferramenta útil no estudo do glaucoma. Este estudo apresenta algumas limitações, como o pequeno número de casos avaliados, sendo necessários maiores estudos para corroborar nossos achados.

  11. Transscleral diode laser retinopexy in retinal reattachment surgery Retinopexia com laser de diodo transescleral na cirurgia de descolamento de retina

    Directory of Open Access Journals (Sweden)

    João Carlos de Miranda Gonçalves

    2004-02-01

    houve reaplicação da retina após um único procedimento cirúrgico com diopexia aplicada em todos os casos. CONCLUSÃO: Fotocoagulação com laser de diodo transescleral foi uma forma tecnicamente fácil, controlada, efetiva, reprodutível e segura na obtenção de adesão coriorretiniana na cirurgia de descolamento de retina.

  12. Demanda por doenças crônico-degenerativas entre adultos matriculados em uma unidade básica de saúde em São Carlos - SP Ocurrencias de males crónico-degenerativos entre adultos inscritos en una unidad básica de salud en São Carlos-SP Demand for chronic-degenerative diseases among adults attended in a basic health unit at the city of São Carlos-SP

    Directory of Open Access Journals (Sweden)

    Adriana Barbieri Feliciano

    1999-07-01

    Full Text Available O estudo teve por objetivo traçar o perfil da clientela maior de 12 anos de idade de uma UBS, segundo variáveis sócio-demográficas como sexo, faixa etária, cor, estado civil e procedência e caracterizar o perfil de morbidade segundo os capítulos da CID (X-Revisão e grupos diagnósticos específicos destacando-se o grupo das doenças crônico-degenerativas, com vistas à sua caracterização no contexto da transição demográfico-epidemiológica. O delineamento foi do tipo transversal, sendo a população base constituída pela clientela matriculada na UBS até 31 de agosto de 1996. Foram excluídos os indivíduos em situação de abandono, os que foram transferidos para outras unidades e aqueles que foram a óbito. A população efetivamente estudada foi composta por 1013 indivíduos. Os dados foram processados no software FOXPRO vs 2.0 e as análises foram efetuadas no EPIINFO vs 6.04. Constatou-se que a população estudada foi basicamente constituída por mulheres (87.1%. Com relação à idade 69.6% estavam entre 12 e 40 anos, 95.6% eram da cor branca, 57.2% eram casados e 97% procedentes da zona urbana. Quando os diagnósticos foram classificados segundo os capítulos da CID destacaram-se as doenças do aparelho geniturinário (35.5%, aparelho respiratório (11.5% e sinais e sintomas (9,9%. A classificação segundo os grupos específicos de causas apontou magnitude semelhante entre as doenças infecto-parasitárias (24.8% e as doenças crônico-degenerativas (24.5%. No grupo de doenças crônico-degenerativas 50% dos capítulos da CID foram compostos pelo conjunto: causas circulatórias, endócrinas e mentais-comportamentais. Observou-se que o perfil de morbidade da UBS parece enquadrar-se no modelo polarizado de transição onde as doenças crônico-degenerativas coexistem com as infecto-parasitárias. O modelo tradicional de atendimento da Unidade que enfoca a saúde materno-infantil parece não adequar-se ao envelhecimento

  13. Whole-Retina Reduced Electrophysiological Activity in Mice Bearing Retina-Specific Deletion of Vesicular Acetylcholine Transporter.

    Directory of Open Access Journals (Sweden)

    Jake Bedore

    Full Text Available Despite rigorous characterization of the role of acetylcholine in retinal development, long-term effects of its absence as a neurotransmitter are unknown. One of the unanswered questions is how acetylcholine contributes to the functional capacity of mature retinal circuits. The current study investigates the effects of disrupting cholinergic signalling in mice, through deletion of vesicular acetylcholine transporter (VAChT in the developing retina, pigmented epithelium, optic nerve and optic stalk, on electrophysiology and structure of the mature retina.A combination of electroretinography, optical coherence tomography imaging and histological evaluation assessed retinal integrity in mice bearing retina- targeted (embryonic day 12.5 deletion of VAChT (VAChTSix3-Cre-flox/flox and littermate controls at 5 and 12 months of age. VAChTSix3-Cre-flox/flox mice did not show any gross changes in nuclear layer cellularity or synaptic layer thickness. However, VAChTSix3-Cre-flox/flox mice showed reduced electrophysiological response of the retina to light stimulus under scotopic conditions at 5 and 12 months of age, including reduced a-wave, b-wave, and oscillatory potential (OP amplitudes and decreased OP peak power and total energy. Reduced a-wave amplitude was proportional to the reduction in b-wave amplitude and not associated with altered a-wave 10%-90% rise time or inner and outer segment thicknesses.This study used a novel genetic model in the first examination of function and structure of the mature mouse retina with disruption of cholinergic signalling. Reduced amplitude across the electroretinogram wave form does not suggest dysfunction in specific retinal cell types and could reflect underlying changes in the retinal and/or extraretinal microenvironment. Our findings suggest that release of acetylcholine by VAChT is essential for the normal electrophysiological response of the mature mouse retina.

  14. Progranulin regulates neurogenesis in the developing vertebrate retina.

    Science.gov (United States)

    Walsh, Caroline E; Hitchcock, Peter F

    2017-09-01

    We evaluated the expression and function of the microglia-specific growth factor, Progranulin-a (Pgrn-a) during developmental neurogenesis in the embryonic retina of zebrafish. At 24 hpf pgrn-a is expressed throughout the forebrain, but by 48 hpf pgrn-a is exclusively expressed by microglia and/or microglial precursors within the brain and retina. Knockdown of Pgrn-a does not alter the onset of neurogenic programs or increase cell death, however, in its absence, neurogenesis is significantly delayed-retinal progenitors fail to exit the cell cycle at the appropriate developmental time and postmitotic cells do not acquire markers of terminal differentiation, and microglial precursors do not colonize the retina. Given the link between Progranulin and cell cycle regulation in peripheral tissues and transformed cells, we analyzed cell cycle kinetics among retinal progenitors following Pgrn-a knockdown. Depleting Pgrn-a results in a significant lengthening of the cell cycle. These data suggest that Pgrn-a plays a dual role during nervous system development by governing the rate at which progenitors progress through the cell cycle and attracting microglial progenitors into the embryonic brain and retina. Collectively, these data show that Pgrn-a governs neurogenesis by regulating cell cycle kinetics and the transition from proliferation to cell cycle exit and differentiation. © 2017 The Authors. Developmental Neurobiology Published by Wiley Periodicals, Inc. Develop Neurobiol 77: 1114-1129, 2017. © 2017 The Authors. Developmental Neurobiology Published by Wiley Periodicals, Inc.

  15. CHANGES IN NEUROTRANSMITTER GENE EXPRESSION IN THE AGING RETINA.

    Science.gov (United States)

    To understand mechanisms of neurotoxicity in susceptible populations, we examined age-related changes in constitutive gene expression in the retinas of young (4mos), middle-aged (11 mos) and aged (23 mos) male Long Evans rats. Derived from a pouch of the forebrain during develop...

  16. Eye Controlled Simulation of Scotoma Effects on the Retina

    Science.gov (United States)

    1990-07-01

    movements since the central region of the viewing. The PRLs were positioned near the retina, the macula , and its center, the fovea, have scotoma boundary...scotoma area; as macular degeneration increases in size. near to the fovea as possible to maximize acuity, Feedback of failures to detect targets might

  17. Near UV radiation effect on the lens and retina

    International Nuclear Information System (INIS)

    Zigman, S.

    1987-01-01

    The discussion presented in this paper indicates that the retina of a diurnal animal with a natural UV-absorbing lens (ie: the gray squirrel) is susceptible to near-UV damage from environmental sources only after the lens has been removed. This suggests that it is very important to protect against near-UV exposure of human eyes after cataract surgery

  18. A digital retina-like low-level vision processor.

    Science.gov (United States)

    Mertoguno, S; Bourbakis, N G

    2003-01-01

    This correspondence presents the basic design and the simulation of a low level multilayer vision processor that emulates to some degree the functional behavior of a human retina. This retina-like multilayer processor is the lower part of an autonomous self-organized vision system, called Kydon, that could be used on visually impaired people with a damaged visual cerebral cortex. The Kydon vision system, however, is not presented in this paper. The retina-like processor consists of four major layers, where each of them is an array processor based on hexagonal, autonomous processing elements that perform a certain set of low level vision tasks, such as smoothing and light adaptation, edge detection, segmentation, line recognition and region-graph generation. At each layer, the array processor is a 2D array of k/spl times/m hexagonal identical autonomous cells that simultaneously execute certain low level vision tasks. Thus, the hardware design and the simulation at the transistor level of the processing elements (PEs) of the retina-like processor and its simulated functionality with illustrative examples are provided in this paper.

  19. Functional Architecture of the Retina: Development and Disease

    Science.gov (United States)

    Hoon, Mrinalini; Okawa, Haruhisa; Santina, Luca Della; Wong, Rachel O.L.

    2014-01-01

    Structure and function are highly correlated in the vertebrate retina, a sensory tissue that is organized into cell layers with microcircuits working in parallel and together to encode visual information. All vertebrate retinas share a fundamental plan, comprising five major neuronal cell classes with cell body distributions and connectivity arranged in stereotypic patterns. Conserved features in retinal design have enabled detailed analysis and comparisons of structure, connectivity and function across species. Each species, however, can adopt structural and/or functional retinal specializations, implementing variations to the basic design in order to satisfy unique requirements in visual function. Recent advances in molecular tools, imaging and electrophysiological approaches have greatly facilitated identification of the cellular and molecular mechanisms that establish the fundamental organization of the retina and the specializations of its microcircuits during development. Here, we review advances in our understanding of how these mechanisms act to shape structure and function at the single cell level, to coordinate the assembly of cell populations, and to define their specific circuitry. We also highlight how structure is rearranged and function is disrupted in disease, and discuss current approaches to re-establish the intricate functional architecture of the retina. PMID:24984227

  20. The effects of microwave radiation on rabbit's retina

    Directory of Open Access Journals (Sweden)

    Mohammad R. Talebnejad

    2018-03-01

    Conclusions: Histopathologically, cell phone simulated MW irradiation had no significant detrimental effect on the retina. However, ciliary body congestion was observed in greater fraction of those who received higher MW doses. Although there was no significant difference between post-treatment mean ERG values, there were statistically non-significant trends toward greater changes in the MW irradiated eyes.

  1. GABA sensitivity of spectrally classified horizontal cells in goldfish retina

    NARCIS (Netherlands)

    Verweij, J.; Kamermans, M.; Negishi, K.; Spekreijse, H.

    1998-01-01

    We studied the GABA sensitivity of horizontal cells in the isolated goldfish retina. After the glutamatergic input to the horizontal cells was blocked with DNQX, GABA depolarized the monophasic and biphasic horizontal cells. The pharmacology of these GABA-induced depolarizations was tested with the

  2. Localization and characterization of immunocompetent cells in the human retina

    NARCIS (Netherlands)

    Yang, P.; Das, P. K.; Kijlstra, A.

    2000-01-01

    Recent studies have shown that experimental uveitis can be induced by the appropriate administration of various retinal antigens. Little is known about the in-situ interactions between immune cells in the retina as a prerequisite for understanding the mechanisms involving the presentation of

  3. Why has Nature Chosen Lutein and Zeaxanthin to Protect the Retina?

    OpenAIRE

    Widomska, Justyna; Subczynski, Witold K

    2014-01-01

    Age-related macular degeneration (AMD) is associated with a low level of macular carotenoids in the eye retina. Only two carotenoids, namely lutein and zeaxanthin are selectively accumulated in the human eye retina from blood plasma where more than twenty other carotenoids are available. The third carotenoid which is found in the human retina, meso-zeaxanthin is formed directly in the retina from lutein. All these carotenoids, named also macular xanthophylls, play key roles in eye health and ...

  4. Spontaneous activity in the developing mammalian retina: Form and function

    Science.gov (United States)

    Butts, Daniel Allison

    Spontaneous neuronal activity is present in the immature mammalian retina during the initial stages of visual system development, before the retina is responsive to light. This activity consists of bursts of action potentials fired by retinal ganglion cells, and propagates in a wavelike manner across the inner plexiform layer of the retina. Unlike waves in other neural systems, retinal waves have large variability in both their rate and direction of propagation, and individual waves only propagate across small regions of the retina. The unique properties of retinal activity arise from dynamic processes within the developing retina, and produce characteristic spatiotemporal properties. These spatiotemporal properties are of particular interest, since they are believed to play a role in visual system development. This dissertation addresses the complex spatiotemporal patterning of the retinal waves from two different perspectives. First, it proposes how the immature circuitry of the developing retina generates these patterns of activity. In order to reproduce the distinct spatiotemporal properties observed in experiments, a model of the immature retinal circuitry must meet certain requirements, which are satisfied by a coarse-grained model of the developing retina that we propose. Second, this dissertation addresses how the particular spatiotemporal patterning of the retinal waves provides information to the rest of the visual system and, as a result, can be used to guide visual system development. By measuring the properties of this information, we place constraints on the developmental mechanisms that use this activity, and show how the particular spatiotemporal properties of the retinal waves provide this information. Together, this dissertation demonstrates how the apparent complexity of retinal wave patterning can be understood both through the immature circuitry that generates it, and through the developmental mechanisms that may use it. The first three

  5. Distribution of photon absorption rates across the rat retina.

    Science.gov (United States)

    Williams, T P; Webbers, J P; Giordano, L; Henderson, R P

    1998-04-15

    1. An investigation into the distribution of light intensity across the rat retina was carried out on excised, intact rat eyes exposed to Ganzfeld illumination from a helium-neon laser (543 nm). 2. Some of the light entering the eyes exits through the sclera where its intensity can be monitored with an optical 'pick-up' that samples the intensity coming from a small region of external sclera and underlying retina. The spatial resolution of the pick-up is such that it samples light that has passed through ca 2 % of the rods in the rat eye. 3. Some of the laser light is absorbed by the rod pigment, rhodopsin, which gradually bleaches. Bleaching in the retina, in turn, causes an exponential increase in intensity emanating from the sclera. By monitoring this intensity increase, we are able to measure two important parameters in a single bleaching run: the local rhodopsin concentration and the local intensity falling on the rods. 4. With an ocular transmission photometer, we have measured both the local intensity and the local rhodopsin concentration across wide regions of rat retina. Both pigmented and albino rats were studied. 5. The distributions of rhodopsin and intensity were both nearly uniform; consequently, the product, (rhodopsin concentration) x (intensity), was similarly nearly equal across the retina. This means that the initial rate of photon absorption is about the same at all retinal locations. 6. Interpreted in terms of photostasis (the regulation of daily photon catch), this means that the rate of photon absorption is about the same in each rod, viz. 14 400 photons absorbed per rod per second. Since this rate of absorption is sufficient to saturate the rod, one possible purpose of photostasis is to maintain the rod system in a saturated state during daylight hours.

  6. Impact of bronchopulmonary dysplasia on brain and retina

    Directory of Open Access Journals (Sweden)

    Annie Wing Hoi Poon

    2016-04-01

    Full Text Available Many premature newborns develop bronchopulmonary dysplasia (BPD, a chronic lung disease resulting from prolonged mechanical ventilation and hyperoxia. BPD survivors typically suffer long-term injuries not only to the lungs, but also to the brain and retina. However, currently it is not clear whether the brain and retinal injuries in these newborns are related only to their prematurity, or also to BPD. We investigated whether the hyperoxia known to cause histologic changes in the lungs similar to BPD in an animal model also causes brain and retinal injuries. Sprague Dawley rat pups were exposed to hyperoxia (95% O2, ‘BPD’ group or room air (21% O2, ‘control’ group from postnatal day 4–14 (P4–14; the rat pups were housed in room air between P14 and P28. At P28, they were sacrificed, and their lungs, brain, and eyes were extracted. Hematoxylin and eosin staining was performed on lung and brain sections; retinas were stained with Toluidine Blue. Hyperoxia exposure resulted in an increased mean linear intercept in the lungs (P<0.0001. This increase was associated with a decrease in some brain structures [especially the whole-brain surface (P=0.02], as well as a decrease in the thickness of the retinal layers [especially the total retina (P=0.0008], compared to the room air control group. In addition, a significant negative relationship was observed between the lung structures and the brain (r=−0.49, P=0.02 and retina (r=−0.70, P=0.0008 structures. In conclusion, hyperoxia exposure impaired lung, brain, and retina structures. More severe lung injuries correlated with more severe brain and retinal injuries. This result suggests that the same animal model of chronic neonatal hyperoxia can be used to simultaneously study lung, brain and retinal injuries related to hyperoxia.

  7. Standard anatomical and visual space for the mouse retina: computational reconstruction and transformation of flattened retinae with the Retistruct package.

    Directory of Open Access Journals (Sweden)

    David C Sterratt

    Full Text Available The concept of topographic mapping is central to the understanding of the visual system at many levels, from the developmental to the computational. It is important to be able to relate different coordinate systems, e.g. maps of the visual field and maps of the retina. Retinal maps are frequently based on flat-mount preparations. These use dissection and relaxing cuts to render the quasi-spherical retina into a 2D preparation. The variable nature of relaxing cuts and associated tears limits quantitative cross-animal comparisons. We present an algorithm, "Retistruct," that reconstructs retinal flat-mounts by mapping them into a standard, spherical retinal space. This is achieved by: stitching the marked-up cuts of the flat-mount outline; dividing the stitched outline into a mesh whose vertices then are mapped onto a curtailed sphere; and finally moving the vertices so as to minimise a physically-inspired deformation energy function. Our validation studies indicate that the algorithm can estimate the position of a point on the intact adult retina to within 8° of arc (3.6% of nasotemporal axis. The coordinates in reconstructed retinae can be transformed to visuotopic coordinates. Retistruct is used to investigate the organisation of the adult mouse visual system. We orient the retina relative to the nictitating membrane and compare this to eye muscle insertions. To align the retinotopic and visuotopic coordinate systems in the mouse, we utilised the geometry of binocular vision. In standard retinal space, the composite decussation line for the uncrossed retinal projection is located 64° away from the retinal pole. Projecting anatomically defined uncrossed retinal projections into visual space gives binocular congruence if the optical axis of the mouse eye is oriented at 64° azimuth and 22° elevation, in concordance with previous results. Moreover, using these coordinates, the dorsoventral boundary for S-opsin expressing cones closely matches

  8. Minocycline counter-regulates pro-inflammatory microglia responses in the retina and protects from degeneration.

    Science.gov (United States)

    Scholz, Rebecca; Sobotka, Markus; Caramoy, Albert; Stempfl, Thomas; Moehle, Christoph; Langmann, Thomas

    2015-11-17

    retina and down-regulated the expression of the microglial activation marker translocator protein (18 kDa) (TSPO), CD68, and activated microglia/macrophage whey acidic protein (AMWAP) already 1 day after light exposure. Furthermore, RNA-seq analyses revealed the potential of minocycline to globally counter-regulate pro-inflammatory gene transcription in the light-damaged retina. The severe thinning of the outer retina and the strong induction of photoreceptor apoptosis induced by light challenge were nearly completely prevented by minocycline treatment as indicated by a preserved retinal structure and a low number of apoptotic cells. Minocycline potently counter-regulates microgliosis and light-induced retinal damage, indicating a promising concept for the treatment of retinal pathologies.

  9. Modeling and Simulation of Microelectrode-Retina Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Beckerman, M

    2002-11-30

    The goal of the retinal prosthesis project is the development of an implantable microelectrode array that can be used to supply visually-driven electrical input to cells in the retina, bypassing nonfunctional rod and cone cells, thereby restoring vision to blind individuals. This goal will be achieved through the study of the fundamentals of electrical engineering, vision research, and biomedical engineering with the aim of acquiring the knowledge needed to engineer a high-density microelectrode-tissue hybrid sensor that will restore vision to millions of blind persons. The modeling and simulation task within this project is intended to address the question how best to stimulate, and communicate with, cells in the retina using implanted microelectrodes.

  10. An analog VLSI chip emulating polarization vision of Octopus retina.

    Science.gov (United States)

    Momeni, Massoud; Titus, Albert H

    2006-01-01

    Biological systems provide a wealth of information which form the basis for human-made artificial systems. In this work, the visual system of Octopus is investigated and its polarization sensitivity mimicked. While in actual Octopus retina, polarization vision is mainly based on the orthogonal arrangement of its photoreceptors, our implementation uses a birefringent micropolarizer made of YVO4 and mounted on a CMOS chip with neuromorphic circuitry to process linearly polarized light. Arranged in an 8 x 5 array with two photodiodes per pixel, each consuming typically 10 microW, this circuitry mimics both the functionality of individual Octopus retina cells by computing the state of polarization and the interconnection of these cells through a bias-controllable resistive network.

  11. Infrared reflectance as a diagnostic adjunct for subclinical commotio retinae

    Directory of Open Access Journals (Sweden)

    Nicholas H Andrew

    2014-01-01

    Full Text Available Commotio retinae (CR is an outer retinal disorder following blunt trauma to the eye. Histologically it is characterized by disruption of the photoreceptor outer segments (OS, typically without injury to other retinal layers. Using spectral-domain optical coherence tomography (OCT the condition is visible as hyper-reflectivity of the OS. Most cases of CR are associated with transient grey-white discoloration of the retina and are easily diagnosed clinically, but there have been reports of OCT-confirmed CR without retinal discoloration. It is likely that this subclinical variant of CR is under-recognized as the OCT features of CR are subtle. Here, we report a case of OCT-confirmed subclinical CR that demonstrated prominent infrared hypo-reflectance, using the infrared protocol of the SPECTRALIS® OCT, Heidelberg Engineering. This case suggests that infrared reflectance may have a role in diagnosing cases of subclinical CR.

  12. Erythropoetin receptor expression in the human diabetic retina

    Directory of Open Access Journals (Sweden)

    Tsang Stephen H

    2009-11-01

    Full Text Available Abstract Background Recent evidence suggests erythropoietin (EPO and the erythropoietin receptor (EPOR may play a direct role in the pathogenesis of diabetic retinopathy. Better characterization of the EPO-EPOR signaling system in the ischemic retina may offer a new therapeutic modality for ischemic ophthalmic diseases. This study was performed to identify EPOR mRNA expression in the human diabetic eye. Findings EPOR antisense RNA probes were validated on human pancreas tissue. In the normal eye, EPOR was expressed in the retinal ganglion cell layer. Minimal expression was observed in the inner and outer nuclear layer. Under conditions of diabetic retinopathy, EPOR expression shifted to photoreceptor cells. Increased expression was also observed in the peripheral retina. Conclusion EPOR expression may be a biomarker or contribute to disease mechanisms in diabetic retinopathy.

  13. Effects of chondroitin sulfate and sodium hyaluronate on chondrocytes and extracellular matrix of articular cartilage in dogs with degenerative joint disease Efeitos do sulfato de condroitina e do hialuronato de sódio nos condrócitos e na matriz extracelular na cartilagem articular de cães com doença articular degenerativa

    Directory of Open Access Journals (Sweden)

    G. Gonçalves

    2008-02-01

    Full Text Available Samples of articular cartilage of femur, tibia and patella of 15 dogs with experimentally induced degenerative joint disease (DJD were microscopically analyzed. Animals were distributed into three groups (n=5: the control group received no medication; the second group was treated with chondroitin sulfate and the third received sodium hyaluronate. Samples were processed and stained with HE and toluidine blue for morphological evaluation. The metabolic and proliferative activity of the chondrocytes was evaluated by the measurement of nucleolar organizer regions (NORs after impregnation by silver nitrate. Significant differences were not observed (P>0.05 in the morphology among the groups, however, the group treated with sodium hyaluronate had a higher score suggesting a trend to a greater severity of the lesions. Significant differences were not observed (P>0.05 in the measurement of NORs, cells and NORs/cells among the groups. Although differences were not significant, sodium hyaluronate group showed higher NOR and cell counts which suggested an increase of the proliferation rate of chondrocytes. In addition, a higher NOR/cell ratio in the group treated with chondroitin sulfate suggested that this drug may have stimulated the metabolic activity of the chondrocytes, minimizing the lesions resulting from DJD.Foram utilizadas amostras de cartilagem articular do fêmur, tíbia e patela de 15 cães com doença articular degenerativa (DAD, induzida experimentalmente. Foram constituídos três grupos de cinco animais: grupo 1 - controle, não medicado; grupo 2 - tratado com sulfato de condroitina e grupo 3 - tratado com hialuronato de sódio. As amostras foram processadas e coradas pelas técnicas de HE e de azul de toluidina para avaliação das alterações morfológicas, e impregnadas pelo nitrato de prata para análise da atividade metabólica e/ou proliferativa dos condrócitos, por meio da visualização e quantificação de regiões organizadoras

  14. Heidelberg Retina Tomograph for the Detection of Glaucoma

    Directory of Open Access Journals (Sweden)

    Barbara Cvenkel

    2012-06-01

    Full Text Available Heidelberg Retina Tomograph (HRT is a confocal scanning laser ophthalmoscope which acquires and analyzes 3-dimensional images of the optic nerve head. The latest instrument HRT3 includes software with larger ethinic-specific normative database. This review summarizes relevant published literature on HRT in diagnosing glaucoma, detecting glaucoma progression, the diagnostic accuracy of HRT among other imaging devices and its role in clinical practice.

  15. Effects and Responses to Spaceflight in the Mouse Retina

    Science.gov (United States)

    Zanello, Susana B.; Theriot, Corey; Westby, Christian; Boyle, Richard

    2011-01-01

    Several stress environmental factors are combined in a unique fashion during spaceflight, affecting living beings widely across their physiological systems. Recently, attention has been placed on vision changes in astronauts returning from long duration missions. Alterations include hyperoptic shift, globe flattening, choroidal folds and optic disc edema, which are probably associated with increased intracranial pressure. These observations justify a better characterization of the ocular health risks associated with spaceflight. This study investigates the impact of spaceflight on the biology of the mouse retina. Within a successful tissue sharing effort, eyes from albino Balb/cJ mice aboard STS-133 were collected for histological analysis and gene expression profiling of the retina at 1 and 7 days after landing. Both vivarium and AEM (Animal Enclosure Module) mice were used as ground controls. Oxidative stress-induced DNA damage was higher in the flight samples compared to controls on R+1, and decreased on R+7. A trend toward higher oxidative and cellular stress response gene expression was also observed on R+1 compared to AEM controls, and these levels decreased on R+7. Several genes coding for key antioxidant enzymes, namely, heme-oxygenase-1, peroxiredoxin, and catalase, were among those upregulated after flight. Likewise, NF B and TGFbeta1, were upregulated in one flight specimen that overall showed the most elevated oxidative stress markers on R+1. In addition, retinas from vivarium control mice evidenced higher oxidative stress markers, NF B and TGFbeta1, likely due to the more intense illumination in vivarium cages versus the AEM. These preliminary data suggest that spaceflight represents a source of environmental stress that translates into oxidative and cellular stress in the retina, which is partially reversible upon return to Earth. Further work is needed to dissect the contribution of the various spaceflight factors (microgravity, radiation) and to

  16. Light regulation of the insulin receptor in the retina.

    Science.gov (United States)

    Rajala, Raju V S; Anderson, Robert E

    2003-10-01

    The peptide hormone insulin binds its cognate cell-surface receptors to activate a coordinated biochemical-signaling network and to induce intracellular events. The retina is an integral part of the central nervous system and is known to contain insulin receptors, although their function is unknown. This article, describes recent studies that link the photobleaching of rhodopsin to tyrosine phosphorylation of the insulin receptor and subsequent activation of phosphoinositide 3- kinase (PI3K). We recently found a light-dependent increase in tyrosine phosphorylation of the insulin receptor-beta-subunit (IR beta) and an increase in PI3K enzyme activity in isolated rod outer segments (ROS) and in anti-phosphotyrosine (PY) and anti-IR beta immunoprecipitates of retinal homogenates. The light effect, which was localized to photoreceptor neurons, is independent of insulin secretion. Our results suggest that light induces tyrosine phosphorylation of IR beta in outer-segment membranes, which leads to the binding of p85 through its N-terminal SH2 domain and the generation of PI-3,4,5-P3. We suggest that the physiological role of this process may be to provide neuroprotection of the retina against light damage by activating proteins that protect against stress-induced apoptosis. The studies linking PI3K activation through tyrosine phosphorylation of IR beta now provide physiological relevance for the presence of these receptors in the retina.

  17. Identification of endogenous flurophores in the layered retina

    Science.gov (United States)

    Xu, Gaixia; Chen, Danni; Sun, Yiwen; Qu, Junle; Lin, Ziyang; Ding, Zhihua; Niu, Hanben

    2007-05-01

    In this paper, we measured and analyzed the characteristic of endogenous fluorophores in porcine layered retina by using advanced fluorescence spectroscopy and microscopy imaging technology. It was found that there were obvious contrasts corresponding to the different layers of retina, which may be important for fundus disease diagnosis. The retinal pigment epithelium cells exhibited strong autofluorescence with as emission peak of 600+/-10nm when excited with 860-nm light. The emission peak of photoreceptors was at 652+/-5nm, and the emission peak of retinal vessels layer was weak and at 640~700nm, when excited with 488-nm light. Autofluorescence images of three layers of retina were obtained using the same setup. We concluded that the main endogenous fluorophore in PRE was lipofuscin and that in retinal vessels was porphyrin. What's more, the FMHW (full width at half. maximum) of retinal fluorescence spectrum was broad, which suggested that there wasn't only one endogenous fluorophores of tissues excited.

  18. A biochemical basis for induction of retina regeneration by antioxidants.

    Science.gov (United States)

    Echeverri-Ruiz, Nancy; Haynes, Tracy; Landers, Joseph; Woods, Justin; Gemma, Michael J; Hughes, Michael; Del Rio-Tsonis, Katia

    2018-01-15

    The use of antioxidants in tissue regeneration has been studied, but their mechanism of action is not well understood. Here, we analyze the role of the antioxidant N-acetylcysteine (NAC) in retina regeneration. Embryonic chicks are able to regenerate their retina after its complete removal from retinal stem/progenitor cells present in the ciliary margin (CM) of the eye only if a source of exogenous factors, such as FGF2, is present. This study shows that NAC modifies the redox status of the CM, initiates self-renewal of the stem/progenitor cells, and induces regeneration in the absence of FGF2. NAC works as an antioxidant by scavenging free radicals either independently or through the synthesis of glutathione (GSH), and/or by reducing oxidized proteins through a thiol disulfide exchange activity. We dissected the mechanism used by NAC to induce regeneration through the use of inhibitors of GSH synthesis and the use of other antioxidants with different biochemical structures and modes of action, and found that NAC induces regeneration through its thiol disulfide exchange activity. Thus, our results provide, for the first time, a biochemical basis for induction of retina regeneration. Furthermore, NAC induction was independent of FGF receptor signaling, but dependent on the MAPK (pErk1/2) pathway. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Light pollution: the possible consequences of excessive illumination on retina.

    Science.gov (United States)

    Contín, M A; Benedetto, M M; Quinteros-Quintana, M L; Guido, M E

    2016-02-01

    Light is the visible part of the electromagnetic radiation within a range of 380-780 nm; (400-700 on primates retina). In vertebrates, the retina is adapted to capturing light photons and transmitting this information to other structures in the central nervous system. In mammals, light acts directly on the retina to fulfill two important roles: (1) the visual function through rod and cone photoreceptor cells and (2) non-image forming tasks, such as the synchronization of circadian rhythms to a 24 h solar cycle, pineal melatonin suppression and pupil light reflexes. However, the excess of illumination may cause retinal degeneration or accelerate genetic retinal diseases. In the last century human society has increased its exposure to artificial illumination, producing changes in the Light/Dark cycle, as well as in light wavelengths and intensities. Although, the consequences of unnatural illumination or light pollution have been underestimated by modern society in its way of life, light pollution may have a strong impact on people's health. The effects of artificial light sources could have direct consequences on retinal health. Constant exposure to different wavelengths and intensities of light promoted by light pollution may produce retinal degeneration as a consequence of photoreceptor or retinal pigment epithelium cells death. In this review we summarize the different mechanisms of retinal damage related to the light exposure, which generates light pollution.

  20. Projeto "construindo um futuro saudável através da prática da atividade física diária" Project "building a healthy future through the daily practice of physical activity"

    Directory of Open Access Journals (Sweden)

    Regina Pozena

    2009-03-01

    Full Text Available O sedentarismo representa um dos principais fatores de risco à saúde, causando um grande impacto na saúde publica, ocasionando o aparecimento de doenças degenerativas não transmissíveis e em um número crescente de pessoas. O objetivo deste trabalho foi verificar a importância da atividade física diária como proposta para auxiliar o controle do sedentarismo e das doenças degenerativas crônicas não transmissíveis na Estratégia Saúde da Família do município de Lourdes (São Paulo. Conclui-se, dessa forma, a uma necessidade urgente de aplicação de programas que visem a um estilo de vida mais ativo e mudanças comportamentais. Pôde-se verificar, através da coleta de dados, a eficácia da atividade física diária na redução e/ou controle das doenças degenerativas não transmissíveis nas pessoas que aderiram ao projeto e a grande importância de um preparo preventivo.Physical inactivity is a major health risk factor at the national and international level. It produces a strong impact on public health, causing the onset of non-transmissible degenerative diseases in a growing number of people. The objective of this study was to verify the importance of daily physical activity as a proposal to help control physical inactivity and chronic non-transmissible degenerative diseases in the Family Health Strategy of the city of Lourdes (state of São Paulo. It is concluded that there is an urgent need of programs aimed at a more active lifestyle and behavioral changes. It was verified, through the data collection, the effectiveness of daily physical activity in the reduction and / or control of non-transmissible degenerative diseases in the people who joined the project and the great importance of prevention for this population.

  1. El ejercicio físico y su prescripción en pacientes con enfermedades crónicas degenerativas Physical exercise and its prescription in patients with chronic degenerative diseases

    Directory of Open Access Journals (Sweden)

    Rossana Gómez

    2010-09-01

    Full Text Available Las enfermedades crónicas degenerativas constituyen una de las principales causas de muerte a nivel mundial, por lo que su crecimiento significativo ha puesto en alerta a varios países, los cuales están adoptando medidas para combatir los factores de riesgos, algunos de los cuales son modificables; siendo el ejercicio regular, un medio de prevención y rehabilitación de estas enfermedades. Esta revisión tiene por objetivo, analizar los parámetros necesarios a tomar en cuenta en la prescripción de un programa de ejercicios en pacientes con obesidad, hipertensión arterial, dislipidemia y diabetes mellitus tipo 2.Chronic degenerative diseases constitute one of the main causes of death at a global level, and their significant increase has alerted many countries, which are taking measures to reduce risk factors, some of which are modifiable; being the regular exercise a means of prevention and rehabilitation of these diseases. The objective of this revision is to analyze the necessary parameters to take into account for the prescription of an exercise program in patients with obesity, high blood pressure dyslipidemia and diabetes mellitus type 2.

  2. LASIK X PRK após cirurgia de descolamento de retina

    Directory of Open Access Journals (Sweden)

    Rodovalho Adriano Jorge Mattoso

    2003-01-01

    Full Text Available OBJETIVO: Comparar os resultados obtidos pelas técnicas de "laser in situ keratomileusis" (LASIK e "photorefractive keratectomy" (PRK na correção de miopia e astigmatismo em olhos previamente submetidos à cirurgia de descolamento de retina (DR com "buckle" escleral. MÉTODOS: Vinte e cinco olhos de 22 pacientes com alterações refracionais significativas após a cirurgia de DR foram submetidos à cirurgia refrativa. Em 14 olhos de 13 pacientes foi realizado LASIK e em 11 olhos de 9 pacientes, PRK. O intervalo mínimo entre a cirurgia de DR e a cirurgia refrativa foi de 12 meses. O tempo de seguimento foi de, pelo menos, 12 meses. RESULTADOS: Doze meses após a cirurgia, a média do equivalente esférico (EE no grupo submetido ao LASIK diminuiu de -6,49 D antes da cirurgia para -0,17 D e a média do cilindro de -1,10 D para -0,23 D. A média do EE no grupo submetido ao PRK foi reduzida de -5,35 D para +0,02 D e a média do cilindro, de -1,38 D para -0,54D. Em ambos os grupos, 11 olhos apresentaram melhora da acuidade visual sem correção de pelo menos 4 linhas. CONCLUSÃO: Tanto o LASIK quanto o PRK foram seguros e eficazes para a correção do erro refracional induzido após a cirurgia de DR. Nossos resultados não apresentaram diferenças significativas entre os procedimentos. Estudos posteriores envolvendo maior amostragem e seguimento mais prolongado contribuirão para melhor avaliação da cirurgia refrativa em pacientes submetidos à cirurgia com "buckle" escleral.

  3. TOPOGRAPHIC ORGANIZATION AND SPECIALIZED AREAS IN THE RETINA OF Callopistes palluma: GANGLION CELL LAYER

    OpenAIRE

    Inzunza, Oscar; Barros B., Zitta; Bravo, Hermes

    1998-01-01

    In this paper we analyze the topographic distribution and cell body size of neurons (ganglion and displaced amacrine) of layer 8 of the retina in the chilean reptile Callopistes palluma; using whole mount retinaswith nissl stain. Callopistes palluma retina has an area centralis without fovea in which the ganglion cell density amounts 20.000 cells / µm2 while the displaced amacrine neurons is about 7.000 cells / µm2. This neural density decreased gradually towards the peripheral retina. A hor...

  4. [VEGF expression in dog retina after chorioretinal venous anastomosis].

    Science.gov (United States)

    Lu, Ning; Li, Zhihui; Sun, Xianli; Wang, Guanglu; Zhang, Feng; Peng, Xiaoyan

    2002-09-01

    To identify changes in vascular endothelial growth factor (VEGF) expression in the dog retina after laser-induced chorioretinal venous anastomosis (CRVA), in order to find out the relationship between CRVA treatment and the related neovascular complications. Immediately after branch retinal vein occlusion (BRVO) model was made in 5 eyes of 5 normal dogs, CRVA treatment was done over a small tributary vein in the drainage distribution of the occluded vein. In each eye, there were 2 - 3 treatment sites. Four to six weeks later, a repeated treatment was given if the first treatment failed to show the anastomosis. The treatment sites with successful CRVA were divided into two groups: the small laser spot group, which received one treatment and the big laser spot group, which received more than one treatment. The expression of VEGF was investigated immunohistochemically in the treatment sites with successful anastomoses and in the 5 normal fellow eyes (control). There were totally 10 successful anastomoses in the 5 experimental eyes, among which, five received one treatment and the other 5 received more than one treatment. On fundus examination, the small laser spots were round and small, and the big laser spots were large with local proliferation. VEGF immunoreactivity was absent/weak in the normal dog retina, and remained unchanged in the small laser spot group, but somewhat increased in the big laser spot group. No neovascular complications occurred. All immunostaining experiments were accompanied by proper controls and none of the negative controls showed any immunoreactivity. Proper laser treatment can induce CRVA quite safely in nonischemic dog retina, which does not cause changes in the expression of VEGF, but severe laser damage in the treatment site can cause increased VEGF expression which may be related to neovascular complications.

  5. Survey of intravitreal injection techniques among retina specialists in Israel

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    Segal O

    2016-06-01

    Full Text Available Ori Segal,1,2 Yael Segal-Trivitz,1,3 Arie Y Nemet,1,2 Noa Geffen,1,2 Ronit Nesher,1,2 Michael Mimouni4 1Department of Ophthalmology, Meir Medical Center, Kfar Saba, 2The Sackler School of Medicine, Tel Aviv University, Tel Aviv, 3Department of Psychiatry, Geha Psychiatric Hospital, Petah Tikva, 4Department of Ophthalmology, Rambam Health Care Campus, Haifa, Israel Purpose: The purpose of this study was to describe antivascular endothelial growth factor intravitreal injection techniques of retinal specialists in order to establish a cornerstone for future practice guidelines. Methods: All members of the Israeli Retina Society were contacted by email to complete an anonymous, 19-question, Internet-based survey regarding their intravitreal injection techniques. Results: Overall, 66% (52/79 completed the survey. Most (98% do not instruct patients to discontinue anticoagulant therapy and 92% prescribe treatment for patients in the waiting room. Three quarters wear sterile gloves and prepare the patient in the supine position. A majority (71% use sterile surgical draping. All respondents apply topical analgesics and a majority (69% measure the distance from the limbus to the injection site. A minority (21% displace the conjunctiva prior to injection. A majority of the survey participants use a 30-gauge needle and the most common quadrant for injection is superotemporal (33%. Less than half routinely assess postinjection optic nerve perfusion (44%. A majority (92% apply prophylactic antibiotics immediately after the injection. Conclusion: The majority of retina specialists perform intravitreal injections similarly. However, a relatively large minority performs this procedure differently. Due to the extremely low percentage of complications, it seems as though such differences do not increase the risk. However, more evidence-based medicine, a cornerstone for practice guidelines, is required in order to identify the intravitreal injection techniques

  6. Instant website optimization for retina displays how-to

    CERN Document Server

    Larson, Kyle J

    2013-01-01

    Written in an accessible and practical manner which quickly imparts the knowledge you want to know. As a How-to book it will use applied examples and teach you to optimize websites for retina displays. This book is for web designers and developers who are familiar with HTML, CSS, and editing graphics who would like to improve their existing website or their next web project with high-resolution images. You'll need to have a high-definition device to be able to test the examples in this book and a server to upload your code to if you're not developing it on that device.

  7. Dual cameras acquisition and display system of retina-like sensor camera and rectangular sensor camera

    Science.gov (United States)

    Cao, Nan; Cao, Fengmei; Lin, Yabin; Bai, Tingzhu; Song, Shengyu

    2015-04-01

    For a new kind of retina-like senor camera and a traditional rectangular sensor camera, dual cameras acquisition and display system need to be built. We introduce the principle and the development of retina-like senor. Image coordinates transformation and interpolation based on sub-pixel interpolation need to be realized for our retina-like sensor's special pixels distribution. The hardware platform is composed of retina-like senor camera, rectangular sensor camera, image grabber and PC. Combined the MIL and OpenCV library, the software program is composed in VC++ on VS 2010. Experience results show that the system can realizes two cameras' acquisition and display.

  8. Protective effect of melatonin in the diabetic rat retina.

    Science.gov (United States)

    Mehrzadi, Saeed; Motevalian, Manijeh; Rezaei Kanavi, Mozhgan; Fatemi, Iman; Ghaznavi, Habib; Shahriari, Mansoor

    2018-03-01

    Diabetic retinopathy (DR) is one of the most common and serious microvascular complications of diabetes. The aim of this study was to evaluate the effects of melatonin (MEL) on retinal injury in diabetic rats. In this study, 21 rats were randomly divided into three groups: control, diabetic, and diabetic + MEL. Streptozotocin was used to induce diabetes at a dose of 50 mg/kg, i.p., and blood glucose was measured to choose the diabetic rats for the study. MEL (20 mg/kg) was given orally for 7 weeks in diabetic rats starting 1 week after induction of diabetes. After 8 weeks, the groups were compared in terms of mean scores of fluorescein leakage, using fluorescein angiography. Reactive oxygen species (ROS) and malondialdehyde (MDA) levels were estimated in retina using commercially available assays. Structural changes in retinas were evaluated by light microscopy. Results showed that diabetes significantly increased the mean scores of fluorescein leakage, and MDA and ROS levels compared to control group. Treatment of the diabetic rats with MEL for 7 weeks prevented the alterations induced by diabetes in comparison with the diabetic control group.Based on these findings, it can be concluded that MEL might have beneficial effects in prevention of DR. © 2018 Société Française de Pharmacologie et de Thérapeutique.

  9. Adaptive Optical System for Retina Imaging Approaches Clinic Applications

    Science.gov (United States)

    Ling, N.; Zhang, Y.; Rao, X.; Wang, C.; Hu, Y.; Jiang, W.; Jiang, C.

    We presented "A small adaptive optical system on table for human retinal imaging" at the 3rd Workshop on Adaptive Optics for Industry and Medicine. In this system, a 19 element small deformable mirror was used as wavefront correction element. High resolution images of photo receptors and capillaries of human retina were obtained. In recent two years, at the base of this system a new adaptive optical system for human retina imaging has been developed. The wavefront correction element is a newly developed 37 element deformable mirror. Some modifications have been adopted for easy operation. Experiments for different imaging wavelengths and axial positions were conducted. Mosaic pictures of photoreceptors and capillaries were obtained. 100 normal and abnormal eyes of different ages have been inspected.The first report in the world concerning the most detailed capillary distribution images cover ±3° by ± 3° field around the fovea has been demonstrated. Some preliminary very early diagnosis experiment has been tried in laboratory. This system is being planned to move to the hospital for clinic experiments.

  10. Possible influences of lutein and zeaxanthin on the developing retina.

    Science.gov (United States)

    Zimmer, J Paul; Hammond, Billy R

    2007-03-01

    The carotenoids lutein and zeaxanthin (LZ) are found throughout the central nervous system but reach their highest concentration within the macular region of the primate retina where they are commonly referred to as the macular pigments. Although LZ are a major integral feature of the central fovea, no information currently exists regarding the effects of variability in the concentration of these pigments on the developing retina. In particular, the long-term effects of very low levels of macular pigment are not known and potentially meaningful. Macular pigment levels depend upon dietary intake since LZ cannot be synthesized de novo. Infants with low intake of LZ (eg, infants receiving unfortified infant formula or breast milk from mothers with low carotenoid diets) would be expected to have considerably lower macular pigment compared with infants with high LZ intake (eg, breast-fed infants with mothers on carotenoid-rich diets). In this paper we discuss possible implications of this difference and the available evidence suggesting that LZ could influence the developing visual system.

  11. Three dimensional reconstruction of tomographic images of the retina

    International Nuclear Information System (INIS)

    Glittenberg, C.; Zeiler, F.; Falkner, C.; Binder, S.; Povazay, B.; Hermann, B.; Drexler, W.

    2007-01-01

    The development of a new display system for the three-dimensional visualization of tomographic images in ophthalmology. Specifically, a system that can use stacks of B-mode scans from an ultrahigh resolution optical tomography examination to vividly display retinal specimens as three-dimensional objects. Several subroutines were programmed in the rendering and raytracing program Cinema 4D XL 9.102 Studio Bundle (Maxon Computer Inc., Friedrichsburg, Germany), which could process stacks of tomographic scans into three-dimensional objects. Ultrahigh resolution optical coherence tomography examinations were performed on patients with various retinal pathologies and post processed with the subroutines that had been designed. All ultrahigh resolution optical coherence tomographies were performed with a titanium: sapphire based ultra broad bandwidth (160 nm) femtosecond laser system (INTEGRAL, Femtolasers Productions GmbH. Vienna Austria) with an axial resolution of 3 μm. A new three dimensional display system for tomographic images in ophthalmology was developed, which allows a highly vivid display of physiological and pathological structures of the retina. The system also distinguishes itself through its high interactivity and adaptability. This new display system allows the visualization of physiological and pathological structures of the retina in a new way, which will give us new insight into their morphology and development. (author) [de

  12. Finestructure of the retina in Garra rufa (cypriniae, Teleostei)

    International Nuclear Information System (INIS)

    Al-Adhami, A. M.; Mir, S.

    1999-01-01

    The light - and dark-adapted retina of the freshwater, bottom-dweller tele ost, Ga rra rufa (Heck el, 1843) was studied under light and electron microscopes. The fish is a fist record in having both falcifrom process and vit real blood circulation and the hyaloid artery from which it developers. A number of acute vision areas represented by increased density of ganglion cell soma ta are evident. The dark-adapted retina is characterized by notably large photoreceptor terminals (rod spherules and cone placidas). A rod spherules has single synaptic ribbon, whereas a cone pedicle has three to four. The inner nuclear layer is composed of the so meta of horizontal, bipolar and amsacrine cells in addition to nuclei of Muller cells. The outer nuclear layer, on the other hand, is composed of two-three rows of rod nuclei and one row of cone nuclei. The photoreceptor cells include rods and single and double cones. The rod outer segments have deep and/or shallow incisor. Cone ellipsoid may have ellipsosomes. These are shown to develop from one of the apical mitochondria of the ellipsoid- Retinomotor movement involves both the photoreceptor cells and the pigment epithelium. (authors). 11 refs., 14 figs

  13. Vsx2 in the zebrafish retina: restricted lineages through derepression

    Directory of Open Access Journals (Sweden)

    Higashijima Shin-ichi

    2009-04-01

    Full Text Available Abstract Background The neurons in the vertebrate retina arise from multipotent retinal progenitor cells (RPCs. It is not clear, however, which progenitors are multipotent or why they are multipotent. Results In this study we show that the homeodomain transcription factor Vsx2 is initially expressed throughout the retinal epithelium, but later it is downregulated in all but a minor population of bipolar cells and all Müller glia. The Vsx2-negative daughters of Vsx2-positive RPCs divide and give rise to all other cell types in the retina. Vsx2 is a repressor whose targets include transcription factors such as Vsx1, which is expressed in the progenitors of distinct non-Vsx2 bipolars, and the basic helix-loop-helix transcription factor Ath5, which restricts the fate of progenitors to retinal ganglion cells, horizontal cells, amacrine cells and photoreceptors fates. Foxn4, expressed in the progenitors of amacrine and horizontal cells, is also negatively regulated by Vsx2. Conclusion Our data thus suggest Vsx2-positive RPCs are fully multipotent retinal progenitors and that when Vsx2 is downregulated, Vsx2-negative progenitors escape Vsx2 repression and so are able to express factors that restrict lineage potential.

  14. Flash photolysis of rhodopsin in the cat retina

    International Nuclear Information System (INIS)

    Ripps, H.; Mehaffey, L.; Siegel, I.M.; Ernst, W.; Kemp, C.M.

    1981-01-01

    The bleaching of rhodopsin by short-duration flashes of a xenon discharge lamp was studied in vivo in the cat retina with the aid of a rapid, spectral-scan fundus reflectometer. Difference spectra recorded over a broad range of intensities showed that the bleaching efficacy of high-intensity flashes was less than that of longer duration, steady lights delivering the same amount of energy. Both the empirical results and those derived from a theoretical analysis of flash photolysis indicate that, under the conditions of these experiments, the upper limit of the flash bleaching of rhodopsin in cat is approximately 90%. Although the fact that a full bleach could not be attained is attributable to photoreversal, i.e., the photic regeneration of rhodopsin from its light-sensitive intermediates, the 90% limit is considerably higher than the 50% (or lower) value obtained under other experimental circumstances. Thus, it appears that the duration (approximately 1 ms) and spectral composition of the flash, coupled with the kinetic parameters of the thermal and photic reactions in the cat retina, reduce the light-induced regeneration of rhodopsin to approximately 10%

  15. Inner neural retina loss in central retinal artery occlusion.

    Science.gov (United States)

    Ikeda, Fumiko; Kishi, Shoji

    2010-09-01

    To report morphologic retinal changes and visual outcomes in acute and chronic central retinal artery occlusion (CRAO). We reviewed ten eyes of ten patients with CRAO (age, 65.3 ± 10.2 years) and measured retinal thicknesses at the central fovea and the perifovea using optical coherence tomography (OCT) over 8 ± 4 months. During the acute phase (within 10 days), the mean inner retinal thicknesses were 148% and 139% of normal values at 1 mm nasal and temporal to the fovea. They decreased to 22% and 11% of normal inner retinal thickness during the chronic phase (3 months or later). The retinal thickness at the perifovea decreased linearly until 3 months but was stable during the chronic phase. In contrast, the foveal thickness increased slightly in the acute phase but was equivalent to the normal level during the chronic phase. As a result of inner retinal atrophy, the foveal pit was shallow during the chronic phase. The final visual acuity was correlated positively with retinal thickness at the perifovea during the chronic CRAO phase. OCT showed that inner retinal necrosis with early swelling and late atrophy occurred in CRAO. The fovea and outer retina appeared to be excluded from ischemic change. The residual inner retina at the perifovea determined the final visual outcomes.

  16. Terapia gênica em distrofias hereditárias de retina Gene therapy for inherited retinal dystrophies

    Directory of Open Access Journals (Sweden)

    Monique Côco

    2009-08-01

    Full Text Available As distrofias hereditárias de retina abrangem um amplo número de doenças caracterizadas por lenta e progressiva degeneração da retina. São o resultado de mutações em genes expressos em fotorreceptores e no epitélio pigmentado da retina. A herança pode ser autossômica dominante, autossômica recessiva, ligada ao X recessiva, digênica ou herança mitocondrial. Atualmente não há tratamento para essas doenças e os pacientes convivem com a perda progressiva da visão. O aconselhamento genético e o suporte para reabilitação têm indicação nestes casos. Pesquisas envolvendo a base molecular e genética dessas doenças está continuamente em expansão e ampliam as perspectivas para novas formas de tratamento. Dessa forma, a terapia gênica, que consiste na inserção de material genético exógeno em células de um indivíduo com finalidade terapêutica, tem sido a principal forma de tratamento para as distrofias hereditárias de retina. O olho é um órgão peculiar para a terapia gênica, pois é anatomicamente dividido em compartimentos, imunologicamente privilegiado e com meios transparentes. A maioria das doenças oculares tem defeitos em genes conhecidos. Além disso, há modelo animal bem caracterizado para algumas condições. Propostas para pesquisa clínica em terapia gênica nas degenerações retinianas hereditárias com defeito no gene RPE65, recentemente tiveram aprovação ética e os resultados preliminares obtidos trouxeram grandes expectativas na melhora da qualidade de vida dos pacientes.The inherited retinal dystrophies comprise a large number of disorders characterized by a slow and progressive retinal degeneration. They are the result of mutations in genes that express in either the photoreceptor cells or the retinal pigment epithelium. The mode of inheritance can be autosomal dominant, autosomal recessive, X linked recessive, digenic or mitochondrial DNA inherited. At the moment, there is no treatment for these

  17. Rod photoreceptors express GPR55 in the adult vervet monkey retina

    DEFF Research Database (Denmark)

    Bouskila, Joseph; Javadi, Pasha; Casanova, Christian

    2013-01-01

    . Yet, its formal classification is still a matter of debate. CB1R and CB2R expression patterns are well described for rodent and monkey retinas. In the monkey retina, CB1R has been localized in its neural (cone photoreceptor, horizontal, bipolar, amacrine and ganglion cells) and CB2R in glial...

  18. Real-time simulation of the retina allowing visualization of each processing stage

    Science.gov (United States)

    Teeters, Jeffrey L.; Werblin, Frank S.

    1991-08-01

    The retina computes to let us see, but can we see the retina compute? Until now, the answer has been no, because the unconscious nature of the processing hides it from our view. Here the authors describe a method of seeing computations performed throughout the retina. This is achieved by using neurophysiological data to construct a model of the retina, and using a special-purpose image processing computer (PIPE) to implement the model in real time. Processing in the model is organized into stages corresponding to computations performed by each retinal cell type. The final stage is the transient (change detecting) ganglion cell. A CCD camera forms the input image, and the activity of a selected retinal cell type is the output which is displayed on a TV monitor. By changing the retina cell driving the monitor, the progressive transformations of the image by the retina can be observed. These simulations demonstrate the ubiquitous presence of temporal and spatial variations in the patterns of activity generated by the retina which are fed into the brain. The dynamical aspects make these patterns very different from those generated by the common DOG (Difference of Gaussian) model of receptive field. Because the retina is so successful in biological vision systems, the processing described here may be useful in machine vision.

  19. Pannexin1 in the outer retina of the zebrafish, Danio rerio

    NARCIS (Netherlands)

    Prochnow, N.; Hoffmann, S.; Vroman, R.; Klooster, J.; Bunse, S.; Kamermans, M.; Dermietzel, R.; Zoidl, G.

    2009-01-01

    In the retina, chemical and electrical synapses couple neurons into functional networks. New candidates encoding for electrical synapse proteins have recently emerged. In the present study, we determined the localization of the candidate protein pannexin1 (zfPanx1) in the zebrafish retina and

  20. Functional and Cellular Responses to Laser Injury in the Rat Snake Retina

    National Research Council Canada - National Science Library

    Glickman, Randolph D; Elliott, III, W. R; Kumar, Neeru

    2007-01-01

    .... This animal is of interest for vision research because its eye has an all-cone retina. A linear array of 5 thermal lesions was placed in the retina of anesthetized animals, near the area centralis, using a Nd:VO4 laser (532 nm...

  1. Preservation of Retina Ganglion Cell Function by Morphine in a Chronic Ocular-Hypertensive Rat Model

    OpenAIRE

    Husain, Shahid; Abdul, Yasir; Crosson, Craig E.

    2012-01-01

    Morphine, a broad range opioid-receptors agonist, provides retina neuroprotection against glaucomatous injury in chronic experimental rat model. Morphine-induced retina neuroprotection in glaucoma model is mediated partly via inhibition of TNF-alpha production and caspase-3 and caspase-8 activation.

  2. Protein changes in the retina following experimental retinal detachment in rabbits

    DEFF Research Database (Denmark)

    Mandal, Nakul; Lewis, Geoffrey P.; Fisher, Steven K.

    2011-01-01

    Retinal detachment leads to the widespread cellular remodeling of the retina. The purpose of this study was to identify protein changes that accompany these cellular alterations by comparing the proteomic profiles of sham and experimentally detached rabbit retina. Elucidation of the proteins most...

  3. A comparison of some organizational characteristics of the mouse central retina and the human macula.

    Science.gov (United States)

    Volland, Stefanie; Esteve-Rudd, Julian; Hoo, Juyea; Yee, Claudine; Williams, David S

    2015-01-01

    Mouse models have greatly assisted our understanding of retinal degenerations. However, the mouse retina does not have a macula, leading to the question of whether the mouse is a relevant model for macular degeneration. In the present study, a quantitative comparison between the organization of the central mouse retina and the human macula was made, focusing on some structural characteristics that have been suggested to be important in predisposing the macula to stresses leading to degeneration: photoreceptor density, phagocytic load on the RPE, and the relative thinness of Bruch's membrane. Light and electron microscopy measurements from retinas of two strains of mice, together with published data on human retinas, were used for calculations and subsequent comparisons. As in the human retina, the central region of the mouse retina possesses a higher photoreceptor cell density and a thinner Bruch's membrane than in the periphery; however, the magnitudes of these periphery to center gradients are larger in the human. Of potentially greater relevance is the actual photoreceptor cell density, which is much greater in the mouse central retina than in the human macula, underlying a higher phagocytic load for the mouse RPE. Moreover, at eccentricities that correspond to the peripheral half of the human macula, the rod to cone ratio is similar between mouse and human. Hence, with respect to photoreceptor density and phagocytic load of the RPE, the central mouse retina models at least the more peripheral part of the macula, where macular degeneration is often first evident.

  4. Clinically and radiological aspects of alterations in humeroradiulnar and hip joints in fila brasileiro dogs.; Aspectos clinicos e radiologicos das alteracoes degenerativas das articulacoes umero-radio-ulnar e coxo-femoral de caes da raca fila brasileiro

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Roberto B. de

    1995-12-31

    Humeroradiulnar and hip joints of 100 fila brasileiro dogs were clinically and radiological studied. the objective was the demonstration of pathologies and their frequency in the metropolitan area of Belo Horizonte, Minas Gerais. The animals were 47 females and 53 males, aged between 9 and 120 months, although 74% of them had less than 36 months and were investigated according their city region and kind of food. Most of the animals came from region III (37%) and used to eat commercial food (32%) and mixed diet composed by commercial food meat and domestic food (26%). Diets with higher density and protein concentrations were more frequent in regions I and III and domestic food in region V. the alterations frequency in the humeroredioulnar joint was 33%. The most frequent pathologies observed were the fragmentation of the coronoid process (39.4%), osteochondrosis dissecans of the medial humeral condyle (31.8%) and ununited anconeal process (28.8%). It was observed significant difference in the frequency of hip dysplasia between the female group (46.5%) and male group (66.7%). For the entire group this frequency was 58%. No significant difference was found in the average inclination angle for normal dogs (149.73 deg {+-} 1.55 deg) and dysplastic dogs dysplasia. Control measures must be applied aiming the reduction of the joint alterations, as the fila brasileiro is a relative new breed. (author). 68 refs., 10 figs., 12 tabs.

  5. Analysis of the 3’ untranslated regions of α-tubulin and S-crystallin mRNA and the identification of CPEB in dark- and light-adapted octopus retinas

    Science.gov (United States)

    Kelly, Shannan; Yamamoto, Hideki

    2008-01-01

    Purpose We previously reported the differential expression and translation of mRNA and protein in dark- and light-adapted octopus retinas, which may result from cytoplasmic polyadenylation element (CPE)–dependent mRNA masking and unmasking. Here we investigate the presence of CPEs in α-tubulin and S-crystallin mRNA and report the identification of cytoplasmic polyadenylation element binding protein (CPEB) in light- and dark-adapted octopus retinas. Methods 3’-RACE and sequencing were used to isolate and analyze the 3’-UTRs of α-tubulin and S-crystallin mRNA. Total retinal protein isolated from light- and dark-adapted octopus retinas was subjected to western blot analysis followed by CPEB antibody detection, PEP-171 inhibition of CPEB, and dephosphorylation of CPEB. Results The following CPE-like sequence was detected in the 3’-UTR of isolated long S-crystallin mRNA variants: UUUAACA. No CPE or CPE-like sequences were detected in the 3’-UTRs of α-tubulin mRNA or of the short S-crystallin mRNA variants. Western blot analysis detected CPEB as two putative bands migrating between 60-80 kDa, while a third band migrated below 30 kDa in dark- and light-adapted retinas. Conclusions The detection of CPEB and the identification of the putative CPE-like sequences in the S-crystallin 3’-UTR suggest that CPEB may be involved in the activation of masked S-crystallin mRNA, but not in the regulation of α-tubulin mRNA, resulting in increased S-crystallin protein synthesis in dark-adapted octopus retinas. PMID:18682811

  6. Rhythmic ganglion cell activity in bleached and blind adult mouse retinas.

    Science.gov (United States)

    Menzler, Jacob; Channappa, Lakshmi; Zeck, Guenther

    2014-01-01

    In retinitis pigmentosa--a degenerative disease which often leads to incurable blindness--the loss of photoreceptors deprives the retina from a continuous excitatory input, the so-called dark current. In rodent models of this disease this deprivation leads to oscillatory electrical activity in the remaining circuitry, which is reflected in the rhythmic spiking of retinal ganglion cells (RGCs). It remained unclear, however, if the rhythmic RGC activity is attributed to circuit alterations occurring during photoreceptor degeneration or if rhythmic activity is an intrinsic property of healthy retinal circuitry which is masked by the photoreceptor's dark current. Here we tested these hypotheses by inducing and analysing oscillatory activity in adult healthy (C57/Bl6) and blind mouse retinas (rd10 and rd1). Rhythmic RGC activity in healthy retinas was detected upon partial photoreceptor bleaching using an extracellular high-density multi-transistor-array. The mean fundamental spiking frequency in bleached retinas was 4.3 Hz; close to the RGC rhythm detected in blind rd10 mouse retinas (6.5 Hz). Crosscorrelation analysis of neighbouring wild-type and rd10 RGCs (separation distance rhythmic RGC spiking in these retinas is driven by a network of presynaptic neurons. The inhibition of glutamatergic ganglion cell input or the inhibition of gap junctional coupling abolished the rhythmic pattern. In rd10 and rd1 retinas the presynaptic network leads to local field potentials, whereas in bleached retinas additional pharmacological disinhibition is required to achieve detectable field potentials. Our results demonstrate that photoreceptor bleaching unmasks oscillatory activity in healthy retinas which shares many features with the functional phenotype detected in rd10 retinas. The quantitative physiological differences advance the understanding of the degeneration process and may guide future rescue strategies.

  7. Damage and functional recovery of the mouse retina after exposure to genotoxic agents

    International Nuclear Information System (INIS)

    Vinogradova, Yu.V.; Tronov, V.A.; Lyakhova, K.N.; Ostrovskij, M.A.

    2013-01-01

    As is known, the mature retina is characterized by high radiation resistance. We showed earlier that ionizing radiation at a dose of ≥25 Gy and the chemical genotoxic agent methylnitrosourea (MNU) in a concentration of ≥60 mg/kg induce acute retinal degeneration, combined with proapoptotic protein expression. The process has a high genotoxic threshold, below which no degeneration signs were traced. The aim of this work was to study the damaging effect of ionizing radiation and MNU on the functional activity of the retina and its ability to recover after exposure to these genotoxicants. The functional activity of the mouse retina was evaluated with electroretinograms (ERG). In parallel, morphological changes in the retina were controlled, and the TUNEL detection of the death of its cell elements was performed. It has been shown that gamma rays or accelerated proton irradiation below 15 Gy cause no structural or functional changes in the mouse retina, which confirms the mature retina's high radiation resistance. Irradiation with a higher dose of 25 Gy leads to photoreceptor layer destruction. This goes along with an increase in the number of the TUNEL-positive photoreceptors, among which are cells with fragmented nuclei, which are typical of apoptosis. MNU in a concentration of 70 mg/kg caused the irreversible loss of the retina's physiological activity, and the morphological degeneration of photoreceptors and their mass death. In a concentration of 35 mg/kg, however, MNU had no cytotoxic effect on the retina. Moreover, this dose caused a reversible ERG amplitude decrease. Also, adaptive response was observed in the retina, which became apparent after two consecutive MNU injections - first, at a dose of 17 mg/kg; then, at a cytotoxic dose of 70 mg/kg. These results point to the possibility of the neurohormesis effect, which was described concerning the retina's exposure to ionizing radiation and some chemicals.

  8. Expression of nitric oxide synthase during the development of RCS rat retinas.

    Science.gov (United States)

    Sharma, R K; Warfvinge, K; Ehinger, B

    2001-01-01

    Nitric oxide (NO) has been reported to be both neurodestructive and neuroprotective in the central nervous system and could possibly play an important role in neurodegenerative disorders. On the assumption that NO synthesis may influence degenerative processes in the retina, we have examined the development and distribution of nitric-oxide-synthase(NOS)-immunoreactive cells in developing Royal College of Surgeons (RCS) rat retinas, which is an animal model for retinal degeneration. An antibody against constitutive neuronal NOS was used for immunocytochemistry on RCS rat retinas from postnatal (PN) days 3, 7, 10, 14, 35, 70 and 281 and compared with that in the normal rats of PN days 3, 7, 10, 14, 54 and adults. Immunoreactive cells were not seen in PN 3 retinas but were distinctly seen in the PN 7 retina along with a plexus in the inner plexiform layer. In both groups (normal and RCS rats) a distinct sublayering of the plexus in the inner plexiform layer could be seen at PN 10, which became more distinct at PN 14. The immunoreactive cells were detected also in the oldest retina examined, which was PN 281 in the case of RCS rats. In both groups, certain amacrine cells, certain bipolar cells and certain horizontal cells were found to be immunoreactive. In conclusion, the developmental timetable of the NOS immunoreactivity was identical in the normal and the RCS rat retinas. The NOS-immunoreactive cells persisted in the RCS retinas even when the retina had degenerated extensively. Abnormalities with the inducible isoforms of NOS cannot be ruled out from this study. We conclude that the chronological and qualitative development of the constitutive neuronal NOS immunoreactivity is normal in RCS rat retinas. Copyright 2001 S. Karger AG, Basel

  9. Wavefront optimized nonlinear microscopy of ex vivo human retinas

    Science.gov (United States)

    Gualda, Emilio J.; Bueno, Juan M.; Artal, Pablo

    2010-03-01

    A multiphoton microscope incorporating a Hartmann-Shack (HS) wavefront sensor to control the ultrafast laser beam's wavefront aberrations has been developed. This instrument allowed us to investigate the impact of the laser beam aberrations on two-photon autofluorescence imaging of human retinal tissues. We demonstrated that nonlinear microscopy images are improved when laser beam aberrations are minimized by realigning the laser system cavity while wavefront controlling. Nonlinear signals from several human retinal anatomical features have been detected for the first time, without the need of fixation or staining procedures. Beyond the improved image quality, this approach reduces the required excitation power levels, minimizing the side effects of phototoxicity within the imaged sample. In particular, this may be important to study the physiology and function of the healthy and diseased retina.

  10. Resonant imaging of carotenoid pigments in the human retina

    Science.gov (United States)

    Gellermann, Werner; Emakov, Igor V.; McClane, Robert W.

    2002-06-01

    We have generated high spatial resolution images showing the distribution of carotenoid macular pigments in the human retina using Raman spectroscopy. A low level of macular pigments is associated with an increased risk of developing age-related macular degeneration, a leading cause of irreversible blindness. Using excised human eyecups and resonant excitation of the pigment molecules with narrow bandwidth blue light from a mercury arc lamp, we record Raman images originating from the carbon-carbon double bond stretch vibrations of lutein and zeaxanthin, the carotenoids comprising human macular pigments. Our Raman images reveal significant differences among subjects, both in regard to absolute levels as well as spatial distribution within the macula. Since the light levels used to obtain these images are well below established safety limits, this technique holds promise for developing a rapid screening diagnostic in large populations at risk for vision loss from age-related macular degeneration.

  11. Simulated annealing in adaptive optics for imaging the eye retina

    International Nuclear Information System (INIS)

    Zommer, S.; Adler, J.; Lipson, S. G.; Ribak, E.

    2004-01-01

    Full Text:Adaptive optics is a method designed to correct deformed images in real time. Once the distorted wavefront is known, a deformable mirror is used to compensate the aberrations and return the wavefront to a plane wave. This study concentrates on methods that omit wave front sensing from the reconstruction process. Such methods use stochastic algorithms to find the extremum of a certain sharpness function, thereby correcting the image without any information on the wavefront. Theoretical work [l] has shown that the optical problem can be mapped onto a model for crystal roughening. The main algorithm applied is simulated annealing. We present a first hardware realization of this algorithm in an adaptive optics system designed to image the retina of the human eye

  12. Using Stem Cells to Model Diseases of the Outer Retina

    Directory of Open Access Journals (Sweden)

    Camille Yvon

    2015-01-01

    Full Text Available Retinal degeneration arises from the loss of photoreceptors or retinal pigment epithelium (RPE. It is one of the leading causes of irreversible blindness worldwide with limited effective treatment options. Generation of induced pluripotent stem cell (IPSC-derived retinal cells and tissues from individuals with retinal degeneration is a rapidly evolving technology that holds a great potential for its use in disease modelling. IPSCs provide an ideal platform to investigate normal and pathological retinogenesis, but also deliver a valuable source of retinal cell types for drug screening and cell therapy. In this review, we will provide some examples of the ways in which IPSCs have been used to model diseases of the outer retina including retinitis pigmentosa (RP, Usher syndrome (USH, Leber congenital amaurosis (LCA, gyrate atrophy (GA, juvenile neuronal ceroid lipofuscinosis (NCL, Best vitelliform macular dystrophy (BVMD and age related macular degeneration (AMD.

  13. Using Stem Cells to Model Diseases of the Outer Retina.

    Science.gov (United States)

    Yvon, Camille; Ramsden, Conor M; Lane, Amelia; Powner, Michael B; da Cruz, Lyndon; Coffey, Peter J; Carr, Amanda-Jayne F

    2015-01-01

    Retinal degeneration arises from the loss of photoreceptors or retinal pigment epithelium (RPE). It is one of the leading causes of irreversible blindness worldwide with limited effective treatment options. Generation of induced pluripotent stem cell (IPSC)-derived retinal cells and tissues from individuals with retinal degeneration is a rapidly evolving technology that holds a great potential for its use in disease modelling. IPSCs provide an ideal platform to investigate normal and pathological retinogenesis, but also deliver a valuable source of retinal cell types for drug screening and cell therapy. In this review, we will provide some examples of the ways in which IPSCs have been used to model diseases of the outer retina including retinitis pigmentosa (RP), Usher syndrome (USH), Leber congenital amaurosis (LCA), gyrate atrophy (GA), juvenile neuronal ceroid lipofuscinosis (NCL), Best vitelliform macular dystrophy (BVMD) and age related macular degeneration (AMD).

  14. Proteomic profiling of early degenerative retina of RCS rats.

    Science.gov (United States)

    Zhu, Zhi-Hong; Fu, Yan; Weng, Chuan-Huang; Zhao, Cong-Jian; Yin, Zheng-Qin

    2017-01-01

    To identify the underlying cellular and molecular changes in retinitis pigmentosa (RP). Label-free quantification-based proteomics analysis, with its advantages of being more economic and consisting of simpler procedures, has been used with increasing frequency in modern biological research. Dystrophic RCS rats, the first laboratory animal model for the study of RP, possess a similar pathological course as human beings with the diseases. Thus, we employed a comparative proteomics analysis approach for in-depth proteome profiling of retinas from dystrophic RCS rats and non-dystrophic congenic controls through Linear Trap Quadrupole - orbitrap MS/MS, to identify the significant differentially expressed proteins (DEPs). Bioinformatics analyses, including Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation and upstream regulatory analysis, were then performed on these retina proteins. Finally, a Western blotting experiment was carried out to verify the difference in the abundance of transcript factor E2F1. In this study, we identified a total of 2375 protein groups from the retinal protein samples of RCS rats and non-dystrophic congenic controls. Four hundred thirty-four significantly DEPs were selected by Student's t -test. Based on the results of the bioinformatics analysis, we identified mitochondrial dysfunction and transcription factor E2F1 as the key initiation factors in early retinal degenerative process. We showed that the mitochondrial dysfunction and the transcription factor E2F1 substantially contribute to the disease etiology of RP. The results provide a new potential therapeutic approach for this retinal degenerative disease.

  15. Proteomic profiling of early degenerative retina of RCS rats

    Directory of Open Access Journals (Sweden)

    Zhi-Hong Zhu

    2017-06-01

    Full Text Available AIM: To identify the underlying cellular and molecular changes in retinitis pigmentosa (RP. METHODS: Label-free quantification-based proteomics analysis, with its advantages of being more economic and consisting of simpler procedures, has been used with increasing frequency in modern biological research. Dystrophic RCS rats, the first laboratory animal model for the study of RP, possess a similar pathological course as human beings with the diseases. Thus, we employed a comparative proteomics analysis approach for in-depth proteome profiling of retinas from dystrophic RCS rats and non-dystrophic congenic controls through Linear Trap Quadrupole - orbitrap MS/MS, to identify the significant differentially expressed proteins (DEPs. Bioinformatics analyses, including Gene ontology (GO and Kyoto Encyclopedia of Genes and Genomes (KEGG pathway annotation and upstream regulatory analysis, were then performed on these retina proteins. Finally, a Western blotting experiment was carried out to verify the difference in the abundance of transcript factor E2F1. RESULTS: In this study, we identified a total of 2375 protein groups from the retinal protein samples of RCS rats and non-dystrophic congenic controls. Four hundred thirty-four significantly DEPs were selected by Student’s t-test. Based on the results of the bioinformatics analysis, we identified mitochondrial dysfunction and transcription factor E2F1 as the key initiation factors in early retinal degenerative process. CONCLUSION: We showed that the mitochondrial dysfunction and the transcription factor E2F1 substantially contribute to the disease etiology of RP. The results provide a new potential therapeutic approach for this retinal degenerative disease.

  16. Photophysical properties of xanthophylls in carotenoproteins from human retinas.

    Science.gov (United States)

    Billsten, Helena H; Bhosale, Prakash; Yemelyanov, Alexander; Bernstein, Paul S; Polívka, Tomás

    2003-08-01

    The macula of the human retina contains high amounts of the xanthophyll carotenoids lutein and zeaxanthin [a mixture of (3R,3'R)-zeaxanthin and (3R,3'S-meso)-zeaxanthin]. Recently, it was shown that the uptake and the stabilization of zeaxanthin and lutein into the retina are likely to be mediated by specific xanthophyll-binding proteins (XBP). Here, we have used femtosecond pump-probe spectroscopy to study the dynamics of the S1 state of these xanthophylls in xanthophyll-enriched and native XBP. The results from the native XBP and the enriched XBP were then compared with those for carotenoids in organic solvents and in detergent micelles. Steady-state and transient absorption spectra show that the incorporation of xanthophylls into the protein causes a redshift of the spectra, which is stronger for lutein than for zeaxanthin. The transient absorption spectra further indicate that a part of the xanthophylls remains unbound in the xanthophyll-enriched XBP. The transient absorption spectra of the native XBP prove the presence of both xanthophylls in native XBP. Although the S1 lifetime of lutein does not exhibit any changes when measured in solution, micelles or XBP, we have observed the influence of the environment on the S1 lifetime of meso-zeaxanthin, which has a longer (12 ps) lifetime in XBP than in solution (9 ps). The most pronounced effect was found for vibrational relaxation in the S1 state, which is significantly slower for xanthophylls in XBP compared with micelles and solution. This effect is more pronounced for meso-zeaxanthin, suggesting a specific site of binding of this carotenoid to XBP.

  17. Alterações da retina periférica após LASIK

    OpenAIRE

    Nassaralla Junior, João Jorge; Santos, Regina Cândido Ribeiro dos; Nassaralla, Belquiz Amaral

    2008-01-01

    PURPOSE: To better define the effect of laser in situ keratomileusis (LASIK) on myopic eyes and the risk and incidence of retinal complications after surgery. METHODS: In a prospective study, 200 eyes of 100 patients, 49 male and 51 female, with a mean age of 29.7 years, had a complete posterior pole examination before and at 1 week, 1, 3 and 12 months after bilateral simultaneous LASIK for the correction of myopia. Mean spherical equivalent was 7.75D (range 1.00 to -17.25D). Before LASIK, pr...

  18. Fatores associados à efetividade da doação de órgãos e tecidos para transplantes

    OpenAIRE

    Freire, Izaura Luzia Silverio

    2013-01-01

    O transplante de órgãos e tecidos apresenta-se como importante opção terapêutica, tanto do ponto de vista médico, quanto social ou econômico. Assim, a identificação das variáveis que podem interferir na efetividade da doação de órgãos e tecidos para transplante precisa ser investigada de maneira adequada, pois se está diante de crescente índice de doenças crônicas e degenerativas na população, que faz com que a lista de espera para transplante aumente desproporcionalmente e os pacientes chega...

  19. Clonal origins of cells in the pigmented retina of the zebrafish eye

    International Nuclear Information System (INIS)

    Streisinger, G.; Coale, F.; Taggart, C.; Walker, C.; Grunwald, D.J.

    1989-01-01

    Mosaic analysis has been used to study the clonal basis of the development of the pigmented retina of the zebrafish, Brachydanio rerio. Zebrafish embryos heterozygous for a recessive mutation at the gol-1 locus were exposed to gamma-irradiation at various developmental stages to create mosaic individuals consisting of wild-type pigmented cells and a clone of pigmentless (golden) cells in the eye. The contribution of individual embryonic cells to the pigmented retina was measured and the total number of cells in the embryo that contributed descendants to this tissue was determined. Until the 32-cell stage, almost every blastomere has some descendants that participate in the formation of the pigmented retina of the zebrafish. During subsequent cell divisions, up to the several thousand-cell stage, the number of ancestral cells is constant: approximately 40 cells are present that will give rise to progeny in the pigmented retina. Analysis of the size of clones in the pigmented retina indicates that the cells of this tissue do not arise through a rigid series of cell divisions originating in the early embryo. The findings that each cleavage stage cell contributes to the pigmented retina and yet the contribution of such cells is highly variable are consistent with the interpretation that clonal descendants of different blastomeres normally intermix extensively prior to formation of the pigmented retina

  20. Distribution of tubulin, kinesin, and dynein in light- and dark-adapted octopus retinas.

    Science.gov (United States)

    Martinez, J M; Elfarissi, H; De Velasco, B; Ochoa, G H; Miller, A M; Clark, Y M; Matsumoto, B; Robles, L J

    2000-01-01

    Cephalopod retinas exhibit several responses to light and dark adaptation, including rhabdom size changes, photopigment movements, and pigment granule migration. Light- and dark-directed rearrangements of microfilament and microtubule cytoskeletal transport pathways could drive these changes. Recently, we localized actin-binding proteins in light-/dark-adapted octopus rhabdoms and suggested that actin cytoskeletal rearrangements bring about the formation and degradation of rhabdomere microvilli subsets. To determine if the microtubule cytoskeleton and associated motor proteins control the other light/dark changes, we used immunoblotting and immunocytochemical procedures to map the distribution of tubulin, kinesin, and dynein in dorsal and ventral halves of light- and dark-adapted octopus retinas. Immunoblots detected alpha- and beta-tubulin, dynein intermediate chain, and kinesin heavy chain in extracts of whole retinas. Epifluorescence and confocal microscopy showed that the tubulin proteins were distributed throughout the retina with more immunoreactivity in retinas exposed to light. Kinesin localization was heavy in the pigment layer of light- and dark-adapted ventral retinas but was less prominent in the dorsal region. Dynein distribution also varied in dorsal and ventral retinas with more immunoreactivity in light- and dark-adapted ventral retinas and confocal microscopy emphasized the granular nature of this labeling. We suggest that light may regulate the distribution of microtubule cytoskeletal proteins in the octopus retina and that position, dorsal versus ventral, also influences the distribution of motor proteins. The microtubule cytoskeleton is most likely involved in pigment granule migration in the light and dark and with the movement of transport vesicles from the photoreceptor inner segments to the rhabdoms.

  1. The organization of melanopsin-immunoreactive cells in microbat retina.

    Science.gov (United States)

    Jeong, Mi-Jin; Kim, Hang-Gu; Jeon, Chang-Jin

    2018-01-01

    Intrinsically photosensitive retinal ganglion cells (ipRGCs) respond to light and play roles in non-image forming vision, such as circadian rhythms, pupil responses, and sleep regulation, or image forming vision, such as processing visual information and directing eye movements in response to visual clues. The purpose of the present study was to identify the distribution, types, and proportion of melanopsin-immunoreactive (IR) cells in the retina of a nocturnal animal, i.e., the microbat (Rhinolophus ferrumequinum). Three types of melanopsin-IR cells were observed in the present study. The M1 type had dendritic arbors that extended into the OFF sublayer of the inner plexiform layer (IPL). M1 soma locations were identified either in the ganglion cell layer (GCL, M1c; 21.00%) or in the inner nuclear layer (INL, M1d; 5.15%). The M2 type had monostratified dendrites in the ON sublayer of the IPL and their cell bodies lay in the GCL (M2; 5.79%). The M3 type was bistratified cells with dendrites in both the ON and OFF sublayers of the IPL. M3 soma locations were either in the GCL (M3c; 26.66%) or INL (M3d; 4.69%). Additionally, some M3c cells had curved dendrites leading up towards the OFF sublayer of the IPL and down to the ON sublayer of the IPL (M3c-crv; 7.67%). Melanopsin-IR cells displayed a medium soma size and medium dendritic field diameters. There were 2-5 primary dendrites and sparsely branched dendrites with varicosities. The total number of the neurons in the GCL was 12,254.17 ± 660.39 and that of the optic nerve axons was 5,179.04 ± 208.00 in the R. ferrumequinum retina. The total number of melanopsin-IR cells was 819.74 ± 52.03. The ipRGCs constituted approximately 15.83% of the total RGC population. This study demonstrated that the nocturnal microbat, R. ferrumequinum, has a much higher density of melanopsin-IR cells than documented in diurnal animals.

  2. The organization of melanopsin-immunoreactive cells in microbat retina.

    Directory of Open Access Journals (Sweden)

    Mi-Jin Jeong

    Full Text Available Intrinsically photosensitive retinal ganglion cells (ipRGCs respond to light and play roles in non-image forming vision, such as circadian rhythms, pupil responses, and sleep regulation, or image forming vision, such as processing visual information and directing eye movements in response to visual clues. The purpose of the present study was to identify the distribution, types, and proportion of melanopsin-immunoreactive (IR cells in the retina of a nocturnal animal, i.e., the microbat (Rhinolophus ferrumequinum. Three types of melanopsin-IR cells were observed in the present study. The M1 type had dendritic arbors that extended into the OFF sublayer of the inner plexiform layer (IPL. M1 soma locations were identified either in the ganglion cell layer (GCL, M1c; 21.00% or in the inner nuclear layer (INL, M1d; 5.15%. The M2 type had monostratified dendrites in the ON sublayer of the IPL and their cell bodies lay in the GCL (M2; 5.79%. The M3 type was bistratified cells with dendrites in both the ON and OFF sublayers of the IPL. M3 soma locations were either in the GCL (M3c; 26.66% or INL (M3d; 4.69%. Additionally, some M3c cells had curved dendrites leading up towards the OFF sublayer of the IPL and down to the ON sublayer of the IPL (M3c-crv; 7.67%. Melanopsin-IR cells displayed a medium soma size and medium dendritic field diameters. There were 2-5 primary dendrites and sparsely branched dendrites with varicosities. The total number of the neurons in the GCL was 12,254.17 ± 660.39 and that of the optic nerve axons was 5,179.04 ± 208.00 in the R. ferrumequinum retina. The total number of melanopsin-IR cells was 819.74 ± 52.03. The ipRGCs constituted approximately 15.83% of the total RGC population. This study demonstrated that the nocturnal microbat, R. ferrumequinum, has a much higher density of melanopsin-IR cells than documented in diurnal animals.

  3. Islet-1 Immunoreactivity in the Developing Retina of Xenopus laevis

    Directory of Open Access Journals (Sweden)

    Guadalupe Álvarez-Hernán

    2013-01-01

    Full Text Available The LIM-homeodomain transcription factor Islet1 (Isl1 has been widely used as a marker of neuronal differentiation in the developing visual system of different classes of vertebrates, including mammals, birds, reptiles, and fish. In the present study, we analyzed the spatial and temporal distribution of Isl1-immunoreactive cells during Xenopus laevis retinal development and its relation to the formation of the retinal layers, and in combination with different markers of cell differentiation. The earliest Isl1 expression appeared at St29-30 in the cell nuclei of sparse differentiating neuroblasts located in the vitreal surface of the undifferentiated retina. At St35-36, abundant Isl1-positive cells accumulated at the vitreal surface of the neuroepithelium. As development proceeded and through the postmetamorphic juveniles, Isl1 expression was identified in subpopulations of ganglion cells and in subsets of amacrine, bipolar, and horizontal cells. These data together suggest a possible role for Isl1 in the early differentiation and maintenance of different retinal cell types, and Isl1 can serve as a specific molecular marker for the study of retinal cell specification in X. laevis.

  4. Development of neural retina in retinopathy of prematurity

    Directory of Open Access Journals (Sweden)

    Yi Luo

    2015-10-01

    Full Text Available Retinopathy of prematurity(ROPis an important cause of infant blindness and visual impairment in the world, of which main clinical characteristics are peripheral retinal vascular abnormalities, including large non-perfusion area and abnormal neovascularization. Numerous researches have demonstrated that ROP affects the differentiation and maturity of retinal photoreceptor cells, with more significantly effect on rods than cones, and later mostly caused ametropia, strabismus, amblyopia and a series of abnormal visual functions, the specific mechanism remains unclear. After treatments, even the retinal vascular proliferation lesions disappear itself, but the abnormal development of photoreceptor cells and the resulting visual dysfunction will persist. Currently the best evaluation mean of clinical assessment about retinal function is mainly visual electrophysiology, especially flash electroretinogram(f-ERG, which can reflect the whole retinal functional status before ganglion cells, has a unique significance for the evaluation of retinal photoreceptor cells function. In this review, we aims at the development of neural retina(mainly photoreceptor cellsand its related mechanisms, also the visual function changes appeared in the late period about ROP and its mechanisms, guiding us to pursuit better methods for treatment.

  5. Mouse embryonic retina delivers information controlling cortical neurogenesis.

    Directory of Open Access Journals (Sweden)

    Ciro Bonetti

    2010-12-01

    Full Text Available The relative contribution of extrinsic and intrinsic mechanisms to cortical development is an intensely debated issue and an outstanding question in neurobiology. Currently, the emerging view is that interplay between intrinsic genetic mechanisms and extrinsic information shape different stages of cortical development. Yet, whereas the intrinsic program of early neocortical developmental events has been at least in part decoded, the exact nature and impact of extrinsic signaling are still elusive and controversial. We found that in the mouse developing visual system, acute pharmacological inhibition of spontaneous retinal activity (retinal waves-RWs during embryonic stages increase the rate of corticogenesis (cell cycle withdrawal. Furthermore, early perturbation of retinal spontaneous activity leads to changes of cortical layer structure at a later time point. These data suggest that mouse embryonic retina delivers long-distance information capable of modulating cell genesis in the developing visual cortex and that spontaneous activity is the candidate long-distance acting extrinsic cue mediating this process. In addition, these data may support spontaneous activity to be a general signal coordinating neurogenesis in other developing sensory pathways or areas of the central nervous system.

  6. Cholesterol in the retina: the best is yet to come

    Science.gov (United States)

    Pikuleva, Irina A.; Curcio, Christine A.

    2014-01-01

    Historically understudied, cholesterol in the retina is receiving more attention now because of genetic studies showing that several cholesterol-related genes are risk factors for age-related macular degeneration (AMD) and because eye pathology studies showing high cholesterol content of drusen, aging Bruch's membrane, and newly found subretinal lesions. The challenge before us is determining how the cholesterol-AMD link is realized. Meeting this challenge will require an excellent understanding these genes’ roles in retinal physiology and how chorioretinal cholesterol is maintained. In the first half of this review, we will succinctly summarize physico-chemical properties of cholesterol, its distribution in the human body, general principles of maintenance and metabolism, and differences in cholesterol handling in human and mouse that impact on experimental approaches. This information will provide a backdrop to the second part of the review focusing on unique aspects of chorioretinal cholesterol homeostasis, aging in Bruch's membrane, cholesterol in AMD lesions, a model for lesion biogenesis, a model for macular vulnerability based on vascular biology, and alignment of AMD-related genes and pathobiology using cholesterol and an atherosclerosis-like progression as unifying features. We conclude with recommendations for the most important research steps we can take towards delineating the cholesterol-AMD link. PMID:24704580

  7. The Analysis of Artificial Retina Organization for Signal Processing

    Institute of Scientific and Technical Information of China (English)

    WEIHui

    2004-01-01

    Machine vision is an active branch of artificial intelligence. An important problem in this area is the trade-off among efficiency, accuracy and computation complexity. The human visual system can keep watchfulness to the perimeter of a viewing field while at the same time focus on the center of the field for fine information processing. This mechanism of appropriate assignment of computing resources can reduce the demand for huge and complex hardware structure. Therefore, the design of a computer model based on the biological visual mechanism is an effective approach to resolve problems in machine vision. In this paper, a multi-layer neural model is developed based on the features of receptive field of ganglion in retina to simulate multi-scale perceptive fields of ganglion cell. The neural model can maintain alert on the outer area of the image while capturing and processing more important information in the central part. It may provide valuable inspiration for the implementation of real-time processing and avoidance of huge computation in machine vision.

  8. Lattice degeneration of the retina and retinal detachment.

    Science.gov (United States)

    Semes, L P

    1992-01-01

    Lattice retinal degeneration is considered the most significant peripheral retinal disorder potentially predisposing to retinal breaks and retinal detachment. Lattice degeneration affects the vitreous and inner retinal layers with secondary changes as deep as the retinal pigment epithelium and perhaps the choriocapillaris. Variations in clinical appearance are the rule; geographically, lattice lesions favor the vertical meridians between the equator and the ora serrata. Lattice degeneration begins early in life and has been reported in sequential generations of the same family. Along with its customary bilateral occurrence, lattice shares other characteristics of a dystrophy. The association between the vitreous and retina in lattice lesions may be responsible for the majority of lattice-induced retinal detachments. The tumultuous event of posterior vitreous separation in the presence of abnormally strong vitreoretinal adherence is the trigger for a retinal tear that, in turn, may lead to retinal detachment. Although retinal holes in young patients with lattice degeneration may play a role in the evolution of retinal detachment, the clinical course of lattice degeneration seems to be one of dormancy rather than of progressive change. This discussion outlines the pathophysiology of lattice retinal degeneration and the relationship of pathophysiology to clinical presentation. The epidemiology of lattice degeneration is summarized, as are the possible precursors to retinal detachment. A clinical characterization of the natural history of lattice degeneration is offered, and interventions for complications are described. To conclude, management strategies from a primary-care standpoint are reviewed.

  9. Frequency spectrum might act as communication code between retina and visual cortex I

    Directory of Open Access Journals (Sweden)

    Xu Yang

    2015-12-01

    Full Text Available AIM: To explore changes and possible communication relationship of local potential signals recorded simultaneously from retina and visual cortex I (V1. METHODS: Fourteen C57BL/6J mice were measured with pattern electroretinogram (PERG and pattern visually evoked potential (PVEP and fast Fourier transform has been used to analyze the frequency components of those signals. RESULTS: The amplitude of PERG and PVEP was measured at about 36.7 µV and 112.5 µV respectively and the dominant frequency of PERG and PVEP, however, stay unchanged and both signals do not have second, or otherwise, harmonic generation. CONCLUSION: The results suggested that retina encodes visual information in the way of frequency spectrum and then transfers it to primary visual cortex. The primary visual cortex accepts and deciphers the input visual information coded from retina. Frequency spectrum may act as communication code between retina and V1.

  10. Müller glia provide essential tensile strength to the developing retina

    Science.gov (United States)

    MacDonald, Ryan B.; Randlett, Owen; Oswald, Julia; Yoshimatsu, Takeshi

    2015-01-01

    To investigate the cellular basis of tissue integrity in a vertebrate central nervous system (CNS) tissue, we eliminated Müller glial cells (MG) from the zebrafish retina. For well over a century, glial cells have been ascribed a mechanical role in the support of neural tissues, yet this idea has not been specifically tested in vivo. We report here that retinas devoid of MG rip apart, a defect known as retinoschisis. Using atomic force microscopy, we show that retinas without MG have decreased resistance to tensile stress and are softer than controls. Laser ablation of MG processes showed that these cells are under tension in the tissue. Thus, we propose that MG act like springs that hold the neural retina together, finally confirming an active mechanical role of glial cells in the CNS. PMID:26416961

  11. Localization, distribution, and connectivity of neuropeptide Y in the human and porcine retinas - a comparative study

    DEFF Research Database (Denmark)

    Christiansen, Anders Tolstrup; Kiilgaard, Jens Folke; Klemp, Kristian

    2018-01-01

    retinal signaling. These findings extend existing knowledge on NPY and NPY-expressing cells in the human and porcine retina showing a high degree of comparability. The extensive distribution and connectivity of NPY-ir cells described in the present study further highlights the potential importance of NPY......Neuropeptide Y (NPY) is a peptide neurotransmitter abundantly expressed in the mammalian retina. Since its discovery, NPY has been studied in retinas of several species, but detailed characterization of morphology, cell-type, and connectivity has never been conducted in larger mammals including...... humans and pigs. As the pig due to size and cellular composition is a well-suited animal for retinal research, we chose to compare the endogenous NPY system of the human retina to that of pigs to support future research in this field. In the present study, using immunohistochemistry, confocal microscopy...

  12. Frequency spectrum might act as communication code between retina and visual cortex I.

    Science.gov (United States)

    Yang, Xu; Gong, Bo; Lu, Jian-Wei

    2015-01-01

    To explore changes and possible communication relationship of local potential signals recorded simultaneously from retina and visual cortex I (V1). Fourteen C57BL/6J mice were measured with pattern electroretinogram (PERG) and pattern visually evoked potential (PVEP) and fast Fourier transform has been used to analyze the frequency components of those signals. The amplitude of PERG and PVEP was measured at about 36.7 µV and 112.5 µV respectively and the dominant frequency of PERG and PVEP, however, stay unchanged and both signals do not have second, or otherwise, harmonic generation. The results suggested that retina encodes visual information in the way of frequency spectrum and then transfers it to primary visual cortex. The primary visual cortex accepts and deciphers the input visual information coded from retina. Frequency spectrum may act as communication code between retina and V1.

  13. Illumination-invariant face recognition with a contrast sensitive silicon retina

    Energy Technology Data Exchange (ETDEWEB)

    Buhmann, J.M. [Rheinische Friedrich-Wilhelms-Univ., Bonn (Germany). Inst. fuer Informatik II; Lades, M. [Bochum Univ. (Germany). Inst. fuer Neuroinformatik; Eeckman, F. [Lawrence Livermore National Lab., CA (United States)

    1993-11-29

    Changes in lighting conditions strongly effect the performance and reliability of computer vision systems. We report face recognition results under drastically changing lighting conditions for a computer vision system which concurrently uses a contrast sensitive silicon retina and a conventional, gain controlled CCD camera. For both input devices the face recognition system employs an elastic matching algorithm with wavelet based features to classify unknown faces. To assess the effect of analog on-chip preprocessing by the silicon retina the CCD images have been digitally preprocessed with a bandpass filter to adjust the power spectrum. The silicon retina with its ability to adjust sensitivity increases the recognition rate up to 50 percent. These comparative experiments demonstrate that preprocessing with an analog VLSI silicon retina generates image data enriched with object-constant features.

  14. Distribution of [35S] taurine in mouse retina after intravitreal and intravascular injection

    International Nuclear Information System (INIS)

    Pourcho, R.G.

    1977-01-01

    The distribution of [ 35 S] taurine in mouse retinae was studied by autoradiographic techniques after either intravitreal or intravascular injection. The route of injection did not affect the final localization. The major sites of label accumulation were the outer nuclear layer, the inner nuclear layer, and Mueller cell processes adjacent to the vitreal surface. The distribution was consistent with the interpretation that taurine was localized within two cellular compartments of mouse retina, photoreceptor cells and Mueller cells. (author)

  15. Localization and Developmental Expression Patterns of CSPG in the RCS Rat Retina

    Directory of Open Access Journals (Sweden)

    Li-Feng Chen

    2011-05-01

    Full Text Available Purpose: Investigate changes in chondroitin sulfate proteoglycan (CSPG distribution in Royal College of Surgeons (RCS rat retinae. Could CSPGs distribution act as a physical barrier to transplanted cell migration in degenerating retinae? Methods: CSPG expression was examined in RCS and Long-Evans rat retinae from birth to postnatal day 150 (PND150 using immunofluorescence and western-blots. Results: Both groups showed a rapid rise in CSPG expression on PND14, which peaked on PND21 before declining to lower levels by PND35. CSPG expression had risen again by PND90 and remained elevated for the duration of the study (PND150. However, from PND21, CSPG expression was significantly higher (p ≤ 0.05, n = 5 in Long-Evans rat retinae. CSPG-positive cells were localized in the ganglion cell layer (GCL and the photoreceptor outer segment debris zone (DZ; CSPG expression in the DZ was the main contributor to the higher expression in older animals for both groups. Conclusions: Increased expression of CSPGs in the DZ may act as a physical barrier following retinal cellular transplantation. CSPGs in the GCL is probably related to dendritic changes. CSPG accumulation in the older retinae suggests that aging influences the microenvironment in the retina, which may affect the efficacy of cell transplantation.

  16. The ciliary margin zone of the mammalian retina generates retinal ganglion cells

    Science.gov (United States)

    Marcucci, Florencia; Murcia-Belmonte, Veronica; Coca, Yaiza; Ferreiro-Galve, Susana; Wang, Qing; Kuwajima, Takaaki; Khalid, Sania; Ross, M. Elizabeth; Herrera, Eloisa; Mason, Carol

    2016-01-01

    Summary The retina of lower vertebrates grows continuously by integrating new neurons generated from progenitors in the ciliary margin zone (CMZ). Whether the mammalian CMZ provides the neural retina with retinal cells is controversial. Live-imaging of embryonic retina expressing eGFP in the CMZ shows that cells migrate laterally from the CMZ to the neural retina where differentiated retinal ganglion cells (RGCs) reside. As Cyclin D2, a cell-cycle regulator, is enriched in ventral CMZ, we analyzed Cyclin D2−/− mice to test whether the CMZ is a source of retinal cells. Neurogenesis is diminished in Cyclin D2 mutants, leading to a reduction of RGCs in the ventral retina. In line with these findings, in the albino retina, the decreased production of ipsilateral RGCs is correlated with fewer Cyclin D2+ cells. Together, these results implicate the mammalian CMZ as a neurogenic site that produces RGCs and whose proper generation depends on Cyclin D2 activity. PMID:28009286

  17. Optic nerve signals in a neuromorphic chip I: Outer and inner retina models.

    Science.gov (United States)

    Zaghloul, Kareem A; Boahen, Kwabena

    2004-04-01

    We present a novel model for the mammalian retina and analyze its behavior. Our outer retina model performs bandpass spatiotemporal filtering. It is comprised of two reciprocally connected resistive grids that model the cone and horizontal cell syncytia. We show analytically that its sensitivity is proportional to the space-constant-ratio of the two grids while its half-max response is set by the local average intensity. Thus, this outer retina model realizes luminance adaptation. Our inner retina model performs high-pass temporal filtering. It features slow negative feedback whose strength is modulated by a locally computed measure of temporal contrast, modeling two kinds of amacrine cells, one narrow-field, the other wide-field. We show analytically that, when the input is spectrally pure, the corner-frequency tracks the input frequency. But when the input is broadband, the corner frequency is proportional to contrast. Thus, this inner retina model realizes temporal frequency adaptation as well as contrast gain control. We present CMOS circuit designs for our retina model in this paper as well. Experimental measurements from the fabricated chip, and validation of our analytical results, are presented in the companion paper [Zaghloul and Boahen (2004)].

  18. Adaptation of the Central Retina for High Acuity Vision: Cones, the Fovea and the Avascular Zone

    Science.gov (United States)

    Provis, Jan M; Dubis, Adam M; Maddess, Ted; Carroll, Joseph

    2013-01-01

    Presence of a fovea centralis is directly linked to molecular specification of an avascular area in central retina, before the fovea (or `pit') begins to form. Modeling suggests that mechanical forces, generated within the eye, initiate formation of a pit within the avascular area, and its later remodeling in the postnatal period. Within the avascular area the retina is dominated by `midget' circuitry, in which signals are transferred from a single cone to a single bipolar cell, then a single ganglion cell. Thus in inner, central retina there are relatively few lateral connections between neurons. This renders the region adaptable to tangential forces, that translocate of ganglion cells laterally / centrifugally, to form the fovea. Optical coherence tomography enables live imaging of the retina, and shows that there is greater variation in the morphology of foveae in humans than previously thought. This variation is associated with differences in size of the avascular area and appears to be genetically based, but can be modified by environmental factors, including prematurity. Even when the fovea is absent (foveal hypoplasia), cones in central retina adopt an elongated and narrow morphology, enabling them to pack more densely to increase the sampling rate, and to act as more effective waveguides. Given these findings, what then is the adaptive advantage of a fovea? We suggest that the advantages of having a pit in central retina are relatively few, and minor, but together work to enhance acuity. PMID:23500068

  19. Defects in the outer limiting membrane are associated with rosette development in the Nrl-/- retina.

    Directory of Open Access Journals (Sweden)

    Michael W Stuck

    Full Text Available The neural retinal leucine zipper (Nrl knockout mouse is a widely used model to study cone photoreceptor development, physiology, and molecular biology in the absence of rods. In the Nrl(-/- retina, rods are converted into functional cone-like cells. The Nrl(-/- retina is characterized by large undulations of the outer nuclear layer (ONL commonly known as rosettes. Here we explore the mechanism of rosette development in the Nrl(-/- retina. We report that rosettes first appear at postnatal day (P8, and that the structure of nascent rosettes is morphologically distinct from what is seen in the adult retina. The lumen of these nascent rosettes contains a population of aberrant cells protruding into the subretinal space that induce infolding of the ONL. Morphologically adult rosettes do not contain any cell bodies and are first detected at P15. The cells found in nascent rosettes are photoreceptors in origin but lack inner and outer segments. We show that the adherens junctions between photoreceptors and Müller glia which comprise the retinal outer limiting membrane (OLM are not uniformly formed in the Nrl(-/- retina and thus allow protrusion of a population of developing photoreceptors into the subretinal space where their maturation becomes delayed. These data suggest that the rosettes of the Nrl(-/- retina arise due to defects in the OLM and delayed maturation of a subset of photoreceptors, and that rods may play an important role in the proper formation of the OLM.

  20. Análise das dosagens e concentrações séricas da ciclosporina A em cães da raça Golden Retriever normais ou afetados pela distrofia muscular

    Directory of Open Access Journals (Sweden)

    Adriana Caroprezo Morini

    2008-04-01

    Full Text Available A distrofia muscular dos cães Golden Retriever (GRMD, uma miopatia degenerativa causada pela ausência da distrofina é geneticamente homóloga à distrofia muscular de Duchenne que acomete humanos, portanto, estes cães são considerados modelos experimentais para estudos em terapia celular. Seu sucesso depende da imunossupressão adequada. A ciclosporina A (CsA é indicada para tal e a monitorização de suas concentrações sangüíneas e efeitos adversos são essenciais para viabilizar a terapia. Foram estudados cães GRMD, e normais da mesma raça, submetidos a terapia com CsA, associada, nos GRMD, ao transplante de células tronco. Foram avaliados as concentrações sangüíneas do fármaco através de amostras coletadas a cada dois ou três dias e analisadas pelo método do imunoensaio por fluorescência (FPIA. Como resultado observamos que as concentrações de CsA oscilaram muito, em seis dos oito animais. Concluímos que as doses variam individualmente sendo de maior importância avaliar a concentração do fármaco no sangue e sua viabilização no uso da terapia celular.

  1. Characteristic lesions in mouse retina irradiated with accelerated iron particles

    International Nuclear Information System (INIS)

    Malachowski, M.J.; Philpott, D.E.; Corbett, R.L.; Tobias, C.A.

    1981-01-01

    A program is underway to determine the radiation hazards of HZE particles using the Bevalac, a heavy-ion accelerator at LBL. Our earlier work with helium, carbon, neon, and argon particles, and exposure to rats to HZE particles in space flight demonstrated some deleterious biological effects. TEM studies have shown that some visual cells were missing and dislocated; these were termed channel lesions. Recently obtained is evidence that a single iron HZE particle may affect a series of cells. Mice were irradiated with 0.1, 0.3, 1, 10, or 25 rad of 590 MeV/amu initial kinetic energy iron particles in groups of 10 animals per dose point. Irradiated and control animals were sacrificed at intervals from one week to two years postirradiation. The eye samples were dehydrated, critical points dried with freon, fractured, and Au-Pd coated for SEM, or plastic embedded, sectioned, and stained for TEM. Additionally, dry fractured samples viewed with the SEM were embedded in plastic, sectioned, and stained for the TEM. Characteristic tunnel shaped lesions were observed with the SEM. Stereo pairs showed tunnels of various lengths up to 100 μm. Light microscopy of serially cut sections from the same material had vacuoles (V) extending the same length. TEM of the same specimen and specimens prepared only for TEM exhibited large vacuoles, greater than or equal to 2 μm, in the inner segment (IS) and outer segment (OS) layers. Severe membrane disruption was found bordering the vacuoles and gross nuclear degeneration (ND) and loose tissue (LT) were seen in the outer nuclear layer (ONL). The number of lesions increased with increasing dose. Microscopy of the control retina failed to demonstrate similar lesions

  2. Endoscopic device for functional imaging of the retina

    Science.gov (United States)

    Barriga, Simon; Lohani, Sweyta; Martell, Bret; Soliz, Peter; Ts'o, Dan

    2011-03-01

    Non-invasive imaging of retinal function based on the recording of spatially distributed reflectance changes evoked by visual stimuli has to-date been performed primarily using modified commercial fundus cameras. We have constructed a prototype retinal functional imager, using a commercial endoscope (Storz) for the frontend optics, and a low-cost back-end that includes the needed dichroic beam splitter to separate the stimulus path from the imaging path. This device has been tested to demonstrate its performance for the delivery of adequate near infrared (NIR) illumination, intensity of the visual stimulus and reflectance return in the imaging path. The current device was found to be capable of imaging reflectance changes of 0.1%, similar to that observable using the modified commercial fundus camera approach. The visual stimulus (a 505nm spot of 0.5secs) was used with an interrogation illumination of 780nm, and a sequence of imaged captured. At each pixel, the imaged signal was subtracted and normalized by the baseline reflectance, so that the measurement was ΔR/R. The typical retinal activity signal observed had a ΔR/R of 0.3-1.0%. The noise levels were measured when no stimulus was applied and found to vary between +/- 0.05%. Functional imaging has been suggested as a means to provide objective information on retina function that may be a preclinical indicator of ocular diseases, such as age-related macular degeneration (AMD), glaucoma, and diabetic retinopathy. The endoscopic approach promises to yield a significantly more economical retinal functional imaging device that would be clinically important.

  3. Bcl-2 expression during the development and degeneration of RCS rat retinae.

    Science.gov (United States)

    Sharma, R K

    2001-12-14

    In various hereditary retinal degenerations, including that in Royal College of Surgeons (RCS) rats, the photoreceptors ultimately die by apoptosis. Bcl-2 is one of the genes, which regulates apoptosis and is thought to promote survival of cells. This study has investigated the developmental expression of Bcl-2 in RCS rat, which is a well-studied animal model for hereditary retinal degeneration. An antibody against Bcl-2 was used for its immunohistochemical localization in dystrophic RCS rat retinae from postnatal (PN) days 4, 7, 13, 35, 45, 70, 202 and 14 months. Results were compared with Bcl-2 localization in congenic non-dystrophic rats from PN 4, 7, 13, 44, 202 and 14 months. Bcl-2 immunoreactivity in non-dystrophic retinae was already present in PN 4 retinae in the nerve fiber layer (presumably in the endfeet of immature Müller cells) and in the proximal parts of certain radially aligned neuroepithelial cells/immature Müller cell radial processes. With increasing age the immunoreactivity in relatively more mature Müller cell radial processes spread distally towards the outer retina and between PN 13 and 44 it reached the adult distribution. No cell bodies in the ganglion cell layer were found to be immunoreactive. Expression of Bcl-2 immunoreactivity in dystrophic RCS rat retinae closely resembled that of non-dystrophic retinae. No immunoreactivity was seen in photoreceptors or retinal pigment epithelium in dystrophic or non-dystrophic retinae. In conclusion, Bcl-2 expression is not altered, either in terms of its chronology or the cell type expressing it, during retinal degeneration in RCS rats.

  4. Effect of ozone therapy on cell apoptosis and angiogenesis in retina tissue of diabetic retinopathy rats

    Institute of Scientific and Technical Information of China (English)

    Xiao Liu

    2016-01-01

    ABSTRACT Objective:To study the effect of ozone therapy on cell apoptosis and angiogenesis in retina tissue of diabetic retinopathy rats.Methods:SD rats were selected as experimental animals and divided into control group, model group and ozone group, and after diabetic models were built, ozone enema was conducted. Retina tissue was collected, TUNEL kits were used to detect the number of apoptotic cells, and Elisa kits were used to detect the contents of nerve damage molecules, angiogenesis-related molecules and endoplasmic reticulum stress molecules. Results:The number of apoptotic cells in retina tissue of model group was significantly more than that of control group, and the number of apoptotic cells in retina tissue of ozone group was significantly less than that of model group; NgR, NR2B, ERK1, ERK2, GFAP, VEGF, STAT-3, HIF-1α, Apelin, APJ, PERK, IRE-1α, ATF-6, eIF2α and XBP-1 contents in retina tissue of model group were significantly higher than those of control group, and PEDF content was lower than that of control group; NgR, NR2B, ERK1, ERK2, GFAP, VEGF, STAT-3, HIF-1α, Apelin, APJ, PERK, IRE-1α, ATF-6, eIF2α and XBP-1 contents in retina tissue of ozone group were significantly lower than those of model group, and PEDF content was higher than that of model group.Conclusion:Ozone therapy can reduce the number of apoptotic cells while reduce nerve cell injury and inhibit angiogenesis and endoplasmic reticulum stress in retina tissue of diabetic rats.

  5. Analysis of MTHFR, CBS, Glutathione, Taurine, and Hydrogen Sulfide Levels in Retinas of Hyperhomocysteinemic Mice.

    Science.gov (United States)

    Cui, Xuezhi; Navneet, Soumya; Wang, Jing; Roon, Penny; Chen, Wei; Xian, Ming; Smith, Sylvia B

    2017-04-01

    Hyperhomocysteinemia (Hhcy) is implicated in certain retinal neurovascular diseases, although whether it is causative remains uncertain. In isolated ganglion cells (GCs), mild Hhcy induces profound death, whereas retinal phenotypes in Hhcy mice caused by mutations in remethylation (methylene tetrahydrofolatereductase [Mthfr+/-]) or transsulfuration pathways (cystathionine β-synthase [Cbs+/-]) demonstrate mild GC loss and mild vasculopathy. The current work investigated compensation in vivo of one pathway for the other, and, because the transsulfuration pathway yields cysteine necessary for formation of glutathione (GSH), taurine, and hydrogen sulfide (H2S), they were analyzed also. Retinas isolated from wild-type (WT), Mthfr+/-, and Cbs+/- mice (12 and 22 weeks) were analyzed for methylene tetrahydrofolate reductase (MTHFR), cystathionine-β-synthase (CBS), and cystathionase (CTH) RNA/protein levels. Retinas were evaluated for levels of reduced:oxidized GSH (GSH:GSSG), Slc7a11 (xCT), taurine, taurine transporter (TAUT), and H2S. Aside from decreased CBS RNA/protein levels in Cbs+/- retinas, there were minimal alterations in remethylation/transsulfuration pathways in the two mutant mice strains. Glutathione and taurine levels in Mthfr+/- and Cbs+/- retinas were similar to WT, which may be due to robust levels of xCT and TAUT in mutant retinas. Interestingly, levels of H2S were markedly increased in retinas of Mthfr+/- and Cbs+/- mice compared with WT. Ganglion cell loss and vasculopathy observed in Mthfr+/- and Cbs+/- mouse retinas may be milder than expected, not because of compensatory increases of enzymes in remethylation/transsulfuration pathways, but because downstream transsulfuration pathway products GSH, taurine, and H2S are maintained at robust levels. Elevation of H2S is particularly intriguing owing to neuroprotective properties reported for this gasotransmitter.

  6. Cold Shock Proteins Are Expressed in the Retina Following Exposure to Low Temperatures.

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    Ignacio M Larrayoz

    Full Text Available Hypothermia has been proposed as a therapeutic intervention for some retinal conditions, including ischemic insults. Cold exposure elevates expression of cold-shock proteins (CSP, including RNA-binding motif protein 3 (RBM3 and cold inducible RNA-binding protein (CIRP, but their presence in mammalian retina is so far unknown. Here we show the effects of hypothermia on the expression of these CSPs in retina-derived cell lines and in the retina of newborn and adult rats. Two cell lines of retinal origin, R28 and mRPE, were exposed to 32°C for different time periods and CSP expression was measured by qRT-PCR and Western blotting. Neonatal and adult Sprague-Dawley rats were exposed to a cold environment (8°C and expression of CSPs in their retinas was studied by Western blotting, multiple inmunofluorescence, and confocal microscopy. RBM3 expression was upregulated by cold in both R28 and mRPE cells in a time-dependent fashion. On the other hand, CIRP was upregulated in R28 cells but not in mRPE. In vivo, expression of CSPs was negligible in the retina of newborn and adult rats kept at room temperature (24°C. Exposure to a cold environment elicited a strong expression of both proteins, especially in retinal pigment epithelium cells, photoreceptors, bipolar, amacrine and horizontal cells, Müller cells, and ganglion cells. In conclusion, CSP expression rapidly rises in the mammalian retina following exposure to hypothermia in a cell type-specific pattern. This observation may be at the basis of the molecular mechanism by which hypothermia exerts its therapeutic effects in the retina.

  7. Estenose degenerativa do canal lombar: correlação entre o índice de Oswestry e imagem de ressonância magnética Estenosis degenerativa del canal lumbar: correlación entre el índice de Oswestry y la resonancia magnética Degenerative lumbar spinal stenosis: correlation between Oswestry index and magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Wagner Pasqualini

    2012-12-01

    Full Text Available OBJETIVOS: Verificar a relação entre o grau de estenose do canal lombar (ECL com a ressonância nuclear magnética (RM e a gravidade da disfunção, de acordo com o Índice de Oswestry em pacientes com ECL e em controles. MÉTODOS: Vinte e três pacientes com diagnóstico de ECL foram comparados com grupo controle de 17 voluntários. Todos foram submetidos a RM e responderam ao questionário de Oswestry. A análise estatística utilizou o teste exato de Fisher, de Mann-Whitney e de Spearman. RESULTADOS: Dor lombar foi a queixa mais frequente em ambos os grupos. O índice de Oswestry mostrou disfunção, em média, em 45,69% no grupo ECL e 11,60% no controle. A RM revelou que a área longitudinal do saco dural, o diâmetro do canal e os recessos laterais e forames estavam igualmente alterados em ambos os grupos. CONCLUSÕES: Não houve correlação entre o grau de estenose e o índice de Oswestry nos dois grupos.OBJETIVOS: Investigar la relación entre el grado de estenosis de canal lumbar (ECL con imágenes de resonancia magnética (RM y la gravedad de la disfunción de acuerdo con el Índice de Oswestry en pacientes con ECL y controles. MÉTODOS: Veintitrés pacientes con un diagnóstico de ECL se compararon con un grupo control de 17 voluntarios. Todos los pacientes fueron sometidos a resonancia magnética y completaron el cuestionario Oswestry. Para el análisis estadístico se utilizó la prueba exacta de Fisher, Mann-Whitney y de Spearman. RESULTADOS: El dolor de espalda es la queja más frecuente en ambos grupos. El índice de disfunción de Oswestry mostró en promedio 45,69% para el grupo ECL y 11,60% para el grupo control. La RM demostró que el área longitudinal del saco dural, el diámetro del canal y de los agujeros y las cavidades laterales se han cambiado de manera similar en ambos grupos. CONCLUSIONES: No se encontró correlación entre el grado de estenosis y el índice de Oswestry en ambos grupos.OBJECTIVES: To verify the

  8. Simultaneous optical coherence tomography and lipofuscin autofluorescence imaging of the retina with a single broadband light source at 480nm

    OpenAIRE

    Jiang, Minshan; Liu, Tan; Liu, Xiaojing; Jiao, Shuliang

    2014-01-01

    We accomplished spectral domain optical coherence tomography and auto-fluorescence microscopy for imaging the retina with a single broadband light source centered at 480 nm. This technique is able to provide simultaneous structural imaging and lipofuscin molecular contrast of the retina. Since the two imaging modalities are provided by the same group of photons, their images are intrinsically registered. To test the capabilities of the technique we periodically imaged the retinas of the same ...

  9. Wnt signaling in form deprivation myopia of the mice retina.

    Directory of Open Access Journals (Sweden)

    Mingming Ma

    Full Text Available BACKGROUND: The canonical Wnt signaling pathway plays important roles in cellular proliferation and differentiation, axonal outgrowth, cellular maintenance in retinas. Here we test the hypothesis that elements of the Wnt signaling pathway are involved in the regulation of eye growth and prevention of myopia, in the mouse form-deprivation myopia model. METHODOLOGY/PRINCIPAL FINDINGS: (1 One hundred twenty-five C57BL/6 mice were randomly distributed into form-deprivation myopia and control groups. Form-deprivation myopia (FDM was induced by suturing the right eyelid, while the control group received no treatment. After 1, 2, and 4 weeks of treatment, eyes were assessed in vivo by cycloplegic retinoscopic refraction and axial length measurement by photography or A-scan ultrasonography. Levels of retinal Wnt2b, Fzd5 and β-catenin mRNA and protein were evaluated using RT-PCR and western blotting, respectively. (2 Another 96 mice were divided into three groups: control, drugs-only, and drugs+FDM (by diffuser. Experimentally treated eyes in the last two groups received intravitreal injections of vehicle or the proteins, DKK-1 (Wnt-pathway antagonist or Norrin (Wnt-pathway agonist, once every three days, for 4 injections total. Axial length and retinoscopic refraction were measured on the 14th day of form deprivation. Following form-deprivation for 1, 2, and 4 weeks, FDM eyes had a relatively myopic refractive error, compared with contralateral eyes. There were no significant differences in refractive error between right and left eye in control group. The amounts of Wnt2b, Fzd5 and β-catenin mRNA and protein were significantly greater in form-deprived myopia eyes than in control eyes.DKK-1 (antagonist reduced the myopic shift in refractive error and increase in axial elongation, whereas Norrin had the opposite effect in FDM eyes. CONCLUSIONS/SIGNIFICANCE: Our studies provide the first evidence that the Wnt2b signaling pathway may play a role in the

  10. Genetic and immunohistochemical analysis of HSPA5 in mouse and human retinas.

    Science.gov (United States)

    Chintalapudi, Sumana R; Wang, XiaoFei; Li, Huiling; Lau, Yin H Chan; Williams, Robert W; Jablonski, Monica M

    2016-01-01

    Photoreceptor degenerative diseases are among the leading causes of vision loss. Although the causative genetic mutations are often known, mechanisms leading to photoreceptor degeneration remain poorly defined. We have previously demonstrated that the photoreceptor membrane-associated protein XAP-1 antigen is a product of the HSPA5 gene. In this study, we used systems genetic methods, statistical modeling, and immunostaining to identify and analyze candidate genes that modulate Hspa5 expression in the retina. Quantitative trait locus (QTL) mapping was used to map the genomic region that regulates Hspa5 in the cross between C57BL/6J X DBA/2J mice (BXD) genetic reference panel. The stepwise refinement of candidate genes was based on expression QTL mapping, gene expression correlation analyses (direct and partial), and analysis of regional sequence variants. The subcellular localization of candidate proteins and HSPA5 in mouse and human retinas was evaluated by immunohistochemistry. Differences in the localization of extracellular HSPA5 were assessed between healthy human donor and atrophic age-related macular degeneration (AMD) donor eyes. In the eyes of healthy mice, extracellular HSPA5 was confined to the area around the cone photoreceptor outer segments. Mapping variation in Hspa5 mRNA expression levels in the retina revealed a statistically significant trans -acting expression QTL (eQTL) on Chromosome 2 (Chr 2) and a suggestive locus on Chr 15. Sulf2 on Chr 2 was the strongest candidate gene based on partial correlation analysis, Pearson correlation with Hspa5 , expression levels in the retina, a missense variant in exon 14, and its reported function in the extracellular matrix and interphotoreceptor matrix. SULF2 is localized to the rod and cone photoreceptors in both human and mouse retinas. In human retinas with no pathology, extracellular HSPA5 was localized around many cones within the macular area. In contrast, fewer HSPA5-immunopositive cones were

  11. Genetic and immunohistochemical analysis of HSPA5 in mouse and human retinas

    Science.gov (United States)

    Chintalapudi, Sumana R.; Wang, XiaoFei; Li, Huiling; Lau, Yin H. Chan; Williams, Robert W.; Jablonski, Monica M.

    2016-01-01

    Purpose Photoreceptor degenerative diseases are among the leading causes of vision loss. Although the causative genetic mutations are often known, mechanisms leading to photoreceptor degeneration remain poorly defined. We have previously demonstrated that the photoreceptor membrane-associated protein XAP-1 antigen is a product of the HSPA5 gene. In this study, we used systems genetic methods, statistical modeling, and immunostaining to identify and analyze candidate genes that modulate Hspa5 expression in the retina. Methods Quantitative trait locus (QTL) mapping was used to map the genomic region that regulates Hspa5 in the cross between C57BL/6J X DBA/2J mice (BXD) genetic reference panel. The stepwise refinement of candidate genes was based on expression QTL mapping, gene expression correlation analyses (direct and partial), and analysis of regional sequence variants. The subcellular localization of candidate proteins and HSPA5 in mouse and human retinas was evaluated by immunohistochemistry. Differences in the localization of extracellular HSPA5 were assessed between healthy human donor and atrophic age-related macular degeneration (AMD) donor eyes. Results In the eyes of healthy mice, extracellular HSPA5 was confined to the area around the cone photoreceptor outer segments. Mapping variation in Hspa5 mRNA expression levels in the retina revealed a statistically significant trans-acting expression QTL (eQTL) on Chromosome 2 (Chr 2) and a suggestive locus on Chr 15. Sulf2 on Chr 2 was the strongest candidate gene based on partial correlation analysis, Pearson correlation with Hspa5, expression levels in the retina, a missense variant in exon 14, and its reported function in the extracellular matrix and interphotoreceptor matrix. SULF2 is localized to the rod and cone photoreceptors in both human and mouse retinas. In human retinas with no pathology, extracellular HSPA5 was localized around many cones within the macular area. In contrast, fewer HSPA5

  12. CLRN1 is nonessential in the mouse retina but is required for cochlear hair cell development.

    Directory of Open Access Journals (Sweden)

    Scott F Geller

    2009-08-01

    Full Text Available Mutations in the CLRN1 gene cause Usher syndrome type 3 (USH3, a human disease characterized by progressive blindness and deafness. Clarin 1, the protein product of CLRN1, is a four-transmembrane protein predicted to be associated with ribbon synapses of photoreceptors and cochlear hair cells, and recently demonstrated to be associated with the cytoskeleton. To study Clrn1, we created a Clrn1 knockout (KO mouse and characterized the histological and functional consequences of Clrn1 deletion in the retina and cochlea. Clrn1 KO mice do not develop a retinal degeneration phenotype, but exhibit progressive loss of sensory hair cells in the cochlea and deterioration of the organ of Corti by 4 months. Hair cell stereocilia in KO animals were longer and disorganized by 4 months, and some Clrn1 KO mice exhibited circling behavior by 5-6 months of age. Clrn1 mRNA expression was localized in the retina using in situ hybridization (ISH, laser capture microdissection (LCM, and RT-PCR. Retinal Clrn1 transcripts were found throughout development and adulthood by RT-PCR, although expression peaked at P7 and declined to undetectable levels in adult retina by ISH. LCM localized Clrn1 transcripts to the retinas inner nuclear layer, and WT levels of retinal Clrn1 expression were observed in photoreceptor-less retinas. Examination of Clrn1 KO mice suggests that CLRN1 is unnecessary in the murine retina but essential for normal cochlear development and function. This may reflect a redundancy in the mouse retina not present in human retina. In contrast to mouse KO models of USH1 and USH2, our data indicate that Clrn1 expression in the retina is restricted to the Müller glia. This is a novel finding, as most retinal degeneration associated proteins are expressed in photoreceptors, not in glia. If CLRN1 expression in humans is comparable to the expression pattern observed in mice, this is the first report of an inner retinal protein that, when mutated, causes retinal

  13. Effect of high-intensity irradiation from dental photopolymerization on the isolated and superfused vertebrate retina.

    Science.gov (United States)

    Rassaei, Mohammad; Thelen, Martin; Abumuaileq, Ramzi; Hescheler, Jürgen; Lüke, Matthias; Schneider, Toni

    2013-03-01

    Light or electromagnetic radiation may damage the neurosensory retina during irradiation of photopolymerizing resinous materials. Direct and indirect effects of irradiation emitted from polymerisation curing light may represent a severe risk factor for the eyes and the skin of the lamp operators, as well as for the patient's oral mucosa. Bovine superfused retinas were used to record their light-evoked electroretinogram (ERG) as ex vivo ERGs. Both the a- and the b-waves were used as indicators for retinal damage on the functional level. The isolated retinas were routinely superfused with a standard nutrient solution under normoglycemic conditions (5 mM D-glucose). The change in the a- and b-wave amplitude and implicit time, caused by low and high intensity irradiation, was calculated and followed over time. From the results, it can be deduced that the irradiation from LED high-power lamps affects severely the normal physiological function of the bovine retina. Irradiations of 1,200 lx irreversibly damaged the physiological response. In part, this may be reversible at lower intensities, but curing without using the appropriate filter will bleach the retinal rhodopsin to a large extent within 20 to 40 s of standard application times. Constant exposure to intense ambient irradiation affects phototransduction (a-wave) as well as transretinal signalling. The proper use of the UV- and blue-light filtering device is highly recommended, and may prevent acute and long lasting damage of the neurosensory retina.

  14. Some indications of structural damage in retina by heavy ion radiation

    International Nuclear Information System (INIS)

    Nelson, A.C.; Hayes, T.L.; Tobias, C.A.; Yang, T.C.

    1981-01-01

    At the Lawrence Berkeley Laboratory Bevalac Facility, iron nuclei were accelerated to an energy of 600 MeV/amu. The beam of iron thus obtained was used to irradiate living biological specimens in order to study possible microscopic tissue damage with the aid of SEM. The experiments involved total head irradiation of live rats which were subsequently returned to their cages to remain for 1 day and 30 days before further examination. After the 1 day and 30 day waits, both eyes were enucleated and placed in chemical fixative followed by ethanol dehydration and critical point drying. Retinas were carefully removed from the eye cups and loaded separately on aluminum stubs which were sputter coated. SEM of the 1 day and 30 day retinas revealed lesions which were not found at all in control retinas. The 1 day and 30 day retinas manifest regions where outer rod segments were missing or rearranged. A single energetic iron nucleus may be capable of generating a retinal lesion which becomes enlarged as biological processes intervene during the 1 day and 30 day waits. Being composed of highly specialized nerve cells, retinas cannot regenerate following irradiation which severely damages the rod cells. Thus one would expect the observed radiation induced retinal lesions to correspond to permanent tissue damage and possible loss of visual acuity in the intact animal

  15. FPGA-Based Real Time, Multichannel Emulated-Digital Retina Model Implementation

    Directory of Open Access Journals (Sweden)

    Zsolt Vörösházi

    2009-01-01

    Full Text Available The function of the low-level image processing that takes place in the biological retina is to compress only the relevant visual information to a manageable size. The behavior of the layers and different channels of the neuromorphic retina has been successfully modeled by cellular neural/nonlinear networks (CNNs. In this paper, we present an extended, application-specific emulated-digital CNN-universal machine (UM architecture to compute the complex dynamic of this mammalian retina in video real time. The proposed emulated-digital implementation of multichannel retina model is compared to the previously developed models from three key aspects, which are processing speed, number of physical cells, and accuracy. Our primary aim was to build up a simple, real-time test environment with camera input and display output in order to mimic the behavior of retina model implementation on emulated digital CNN by using low-cost, moderate-sized field-programmable gate array (FPGA architectures.

  16. Frequency of Toxoplasma gondii in the retina in eye banks in Brazil.

    Science.gov (United States)

    Costa, Deise F; Nascimento, Heloisa; Sutili, Aline; Nobrega, Fernando A J; Fowler, Flavio; Nobrega, Mario Junqueira; Garrido, Cristina; de Oliveira Dias, Janaina; Adán, Consuelo B D; Rizzo, Luiz Vicente; Silveira, Claudio; Belfort, Rubens; Commodaro, Alessandra G

    2017-07-01

    Ocular toxoplasmosis is the main cause of posterior uveitis worldwide frequently leading to vision loss. In Brazil, the seroprevalence of Toxoplasma gondii infection ranges from 50 to 80% depending of the region studied. The frequency of toxoplasmic retinal scar may reach 18% of the adults in the South of Brazil. Our goal was to determine the frequency of T. gondii DNA in retinas from eye banks from different regions in Brazil. A total of 162 eyes were obtained from eye banks in Manaus (n = 60), Sao Paulo (n = 60), Chapeco (n = 26), and Joinville (n = 16). The retinas were macroscopically analyzed and collected for DNA extraction. Real-time PCR (qPCR) was performed using the T. gondii B1 marker. By qPCR, a higher frequency of T. gondii DNA in the retinas from the eye bank of Joinville (25%) was found when compared to Manaus (5%). The retinas from Sao Paulo and Chapeco were qPCR negative. Clinical examination determined the retina lesions to be compatible with toxoplasmosis in the following frequencies: Joinville (62.5%), Manaus (10%), Sao Paulo (6.7%), and Chapeco (15.4%).

  17. Training and professional profile of retinologists in Spain: Retina 2 project, Report 4.

    Science.gov (United States)

    Pastor, J Carlos; Fernández, Itziar; Rojas, Jimena; Coco, Rosa; Sanabria, Maria R; Rodríguez-de la Rúa, Enrique; Sánchez, Diego; Valverde, Carmen; Sala-Puigdollers, Anna

    2011-01-01

    Uniform postresidency systems to train medical specialists have not been developed in most European countries. Before developing a framework for such a system, we established the learning and professional profiles of Spanish ophthalmologists dedicated to medical retina and vitreoretina subspecialties. After identification of presumed subspecialists by experts from different autonomous regions, a self-administered questionnaire was mailed in 2006. A reminder was sent three weeks later. Postal mail was used. Nonresponder bias was determined. Of 492 possible retina subspecialists, 261 replied to the questionnaires. While about 86% received specific retinal training, standardized fellowship programs were uncommon for both medical retina and vitreoretina (around 10%). Of the responders, 24.5% performed only medical retina, 11.8% vitreoretina, and 63.6% both. Most (60.5%) practiced anterior segment surgery, and 78.7% declared skills in vitrectomy. We have developed a database of Spanish ophthalmologists dedicated to retinal pathologies and identified some characteristics of their professional profile. Although most of them have received specific retinal training, standardized mastership programs are still uncommon. These data will be useful in creating a standardized Retina Mastership, an important goal of the European Higher Education Area.

  18. Benign familial fleck retina: multimodal imaging including optical coherence tomography angiography.

    Science.gov (United States)

    Garcia, Jose Mauricio Botto de Barros; Isaac, David Leonardo Cruvinel; Sardeiro, Tainara; Aquino, Érika; Avila, Marcos

    2017-01-01

    This report presents multimodal imaging of a 27-year-old woman diagnosed with benign familial fleck retina (OMIM 228980), an uncommon disorder. Fundus photographs revealed retinal flecks that affected her post-equatorial retina but spared the macular area. Fundus autofluorescence and infrared imaging demonstrated a symmetrical pattern of yellow-white fleck lesions that affected both eyes. Her full-field electroretinogram and electrooculogram were normal. An optical coherence tomography B-scan was performed for both eyes, revealing increased thickness of the retinal pigmented epithelium leading to multiple small pigmented epithelium detachments. The outer retina remained intact in both eyes. Spectral-domain optical coherence tomography angiography with split-spectrum amplitude decorrelation algorithm and 3 × 3 mm structural en face optical coherence tomography did not show macular lesions. Benign familial fleck retina belongs to a heterogenous group of so-called flecked retina syndromes, and should be considered in patients with yellowish-white retinal lesions without involvement of the macula.

  19. Autofluorescence from the outer retina and subretinal space: hypothesis and review.

    Science.gov (United States)

    Spaide, Richard

    2008-01-01

    To review the pathophysiologic principles underlying increased autofluorescence from the outer retina and subretinal space using selected diseases as examples. The ocular imaging information and histopathologic features, when known, were integrated for diseases causing increased autofluorescence from the outer retina and subretinal space. Inferences were taken from this information and used to create a classification scheme. These diseases are principally those that cause separation of the outer retina from the retinal pigment epithelium, thereby preventing proper phagocytosis of photoreceptor outer segments. The separation can arise from increased exudation into the subretinal space or inadequate removal of fluid from the subretinal space. Lack of normal outer segment processing initially leads to increased accumulation of outer segments on the outer retina and subretinal space. Over time, this material is visible as an increasingly thick coating on the outer retina, is yellow, and is autofluorescent. Over time, atrophy develops with thinning of the deposited material and decreasing autofluorescence. The accumulated material is ultimately capable of inducing damage to the retinal pigment epithelium. Diseases causing accumulation of the material include central serous chorioretinopathy, vitelliform macular dystrophy, acute exudative polymorphous vitelliform maculopathy, choroidal tumors, and vitreomacular traction syndrome. The physical separation of the retinal outer segments from the retinal pigment epithelium hinders proper phagocytosis of the outer segments. Accumulation of the shed but not phagocytized outer segments plays a role in disease manifestations for a number of macular diseases.

  20. Benign familial fleck retina: multimodal imaging including optical coherence tomography angiography

    Directory of Open Access Journals (Sweden)

    Jose Mauricio Botto de Barros Garcia

    Full Text Available ABSTRACT This report presents multimodal imaging of a 27-year-old woman diagnosed with benign familial fleck retina (OMIM 228980, an uncommon disorder. Fundus photographs revealed retinal flecks that affected her post-equatorial retina but spared the macular area. Fundus autofluorescence and infrared imaging demonstrated a symmetrical pattern of yellow-white fleck lesions that affected both eyes. Her full-field electroretinogram and electrooculogram were normal. An optical coherence tomography B-scan was performed for both eyes, revealing increased thickness of the retinal pigmented epithelium leading to multiple small pigmented epithelium detachments. The outer retina remained intact in both eyes. Spectral-domain optical coherence tomography angiography with split-spectrum amplitude decorrelation algorithm and 3 × 3 mm structural en face optical coherence tomography did not show macular lesions. Benign familial fleck retina belongs to a heterogenous group of so-called flecked retina syndromes, and should be considered in patients with yellowish-white retinal lesions without involvement of the macula.

  1. Two-Photon Autofluorescence Imaging Reveals Cellular Structures Throughout the Retina of the Living Primate Eye.

    Science.gov (United States)

    Sharma, Robin; Williams, David R; Palczewska, Grazyna; Palczewski, Krzysztof; Hunter, Jennifer J

    2016-02-01

    Although extrinsic fluorophores can be introduced to label specific cell types in the retina, endogenous fluorophores, such as NAD(P)H, FAD, collagen, and others, are present in all retinal layers. These molecules are a potential source of optical contrast and can enable noninvasive visualization of all cellular layers. We used a two-photon fluorescence adaptive optics scanning light ophthalmoscope (TPF-AOSLO) to explore the native autofluorescence of various cell classes spanning several layers in the unlabeled retina of a living primate eye. Three macaques were imaged on separate occasions using a custom TPF-AOSLO. Two-photon fluorescence was evoked by pulsed light at 730 and 920 nm excitation wavelengths, while fluorescence emission was collected in the visible range from several retinal layers and different locations. Backscattered light was recorded simultaneously in confocal modality and images were postprocessed to remove eye motion. All retinal layers yielded two-photon signals and the heterogeneous distribution of fluorophores provided optical contrast. Several structural features were observed, such as autofluorescence from vessel walls, Müller cell processes in the nerve fibers, mosaics of cells in the ganglion cell and other nuclear layers of the inner retina, as well as photoreceptor and RPE layers in the outer retina. This in vivo survey of two-photon autofluorescence throughout the primate retina demonstrates a wider variety of structural detail in the living eye than is available through conventional imaging methods, and broadens the use of two-photon imaging of normal and diseased eyes.

  2. Local edge detectors: a substrate for fine spatial vision at low temporal frequencies in rabbit retina.

    Science.gov (United States)

    van Wyk, Michiel; Taylor, W Rowland; Vaney, David I

    2006-12-20

    Visual acuity is limited by the size and density of the smallest retinal ganglion cells, which correspond to the midget ganglion cells in primate retina and the beta-ganglion cells in cat retina, both of which have concentric receptive fields that respond at either light-On or light-Off. In contrast, the smallest ganglion cells in the rabbit retina are the local edge detectors (LEDs), which respond to spot illumination at both light-On and light-Off. However, the LEDs do not predominate in the rabbit retina and the question arises, what role do they play in fine spatial vision? We studied the morphology and physiology of LEDs in the isolated rabbit retina and examined how their response properties are shaped by the excitatory and inhibitory inputs. Although the LEDs comprise only approximately 15% of the ganglion cells, neighboring LEDs are separated by 30-40 microm on the visual streak, which is sufficient to account for the grating acuity of the rabbit. The spatial and temporal receptive-field properties of LEDs are generated by distinct inhibitory mechanisms. The strong inhibitory surround acts presynaptically to suppress both the excitation and the inhibition elicited by center stimulation. The temporal properties, characterized by sluggish onset, sustained firing, and low bandwidth, are mediated by the temporal properties of the bipolar cells and by postsynaptic interactions between the excitatory and inhibitory inputs. We propose that the LEDs signal fine spatial detail during visual fixation, when high temporal frequencies are minimal.

  3. Comparative proteomic analyses of macular and peripheral retina of cynomolgus monkeys (Macaca fascicularis).

    Science.gov (United States)

    Okamoto, Haru; Umeda, Shinsuke; Nozawa, Takehiro; Suzuki, Michihiro T; Yoshikawa, Yasuhiro; Matsuura, Etsuko T; Iwata, Takeshi

    2010-01-01

    The central region of the primate retina is called the macula. The fovea is located at the center of the macula, where the photoreceptors are concentrated to create a neural network adapted for high visual acuity. Damage to the fovea, e.g., by macular dystrophies and age-related macular degeneration, can reduce central visual acuity. The molecular mechanisms leading to these diseases are most likely dependent on the proteins in the macula which differ from those in the peripheral retina in expression level. To investigate whether the distribution of proteins in the macula is different from the peripheral retina, proteomic analyses of tissues from these two regions of cynomolgus monkeys were compared. Two-dimensional gel electrophoresis and mass spectrometry identified 26 proteins that were present only in the macular gel spots. The expression levels of five proteins, cone photoreceptor specific arrestin-C, gamma-synuclein, epidermal fatty acid binding protein, tropomyosin 1alpha chain, and heterogeneous nuclear ribonucleoproteins A2/B1, were significantly higher in the macula than in the peripheral retina. Immunostaining of macula sections by antibodies to each identified protein revealed unique localization in the retina, retinal pigment epithelial cells and the choroidal layer. Some of these proteins were located in cells with higher densities in the macula. We suggest that it will be important to study these proteins to determine their contribution to the pathogenesis and progression of macula diseases.

  4. Complement anaphylatoxin C3a is a potent inducer of embryonic chick retina regeneration

    Science.gov (United States)

    Haynes, Tracy; Luz-Madrigal, Agustin; Reis, Edimara S.; Echeverri Ruiz, Nancy P.; Grajales-Esquivel, Erika; Tzekou, Apostolia; Tsonis, Panagiotis A.; Lambris, John D.; Del Rio-Tsonis, Katia

    2013-01-01

    Identifying the initiation signals for tissue regeneration in vertebrates is one of the major challenges in regenerative biology. Much of the research thus far has indicated that certain growth factors have key roles. Here we show that complement fragment C3a is sufficient to induce complete regeneration of the embryonic chick retina from stem/progenitor cells present in the eye, independent of fibroblast growth factor receptor signaling. Instead, C3a induces retina regeneration via STAT3 activation, which in turn activates the injury- and inflammation-responsive factors, IL-6, IL-8 and TNF-α. This activation sets forth regulation of Wnt2b, Six3 and Sox2, genes associated with retina stem and progenitor cells. Thus, our results establish a mechanism for retina regeneration based on injury and inflammation signals. Furthermore, our results indicate a unique function for complement anaphylatoxins that implicate these molecules in the induction and complete regeneration of the retina, opening new avenues of experimentation in the field. PMID:23942241

  5. HB-EGF is necessary and sufficient for Müller glia dedifferentiation and retina regeneration

    Science.gov (United States)

    Wan, Jin; Ramachandran, Rajesh; Goldman, Daniel

    2011-01-01

    Summary Müller glia (MG) dedifferentiation into a cycling population of multipotent progenitors is crucial to zebrafish retina regeneration. The mechanisms underlying MG dedifferentiation are unknown. Here we report that heparin-binding epidermal-like growth factor (HB-EGF) is rapidly induced in MG residing at the injury site and that proHB-EGF ectodomain shedding is necessary for retina regeneration. Remarkably, HB-EGF stimulates the formation of multipotent MG-derived progenitors in the uninjured retina. We show that HB-EGF mediates its effects via an EGFR/MAPK signal transduction cascade that regulates the expression of regeneration-associated genes, like ascl1a and pax6b. We also uncover an HB-EGF/Ascl1a/Notch/hb-egfa signaling loop that helps define the zone of injury-responsive MG. Finally, we show that HB-EGF acts upstream of the Wnt/β-catenin signaling cascade that controls progenitor proliferation. These data provide a link between extracellular signaling and regeneration-associated gene expression in the injured retina and suggest strategies for stimulating retina regeneration in mammals. PMID:22340497

  6. The Retinome – Defining a reference transcriptome of the adult mammalian retina/retinal pigment epithelium

    Directory of Open Access Journals (Sweden)

    Goetz Thomas

    2004-07-01

    Full Text Available Abstract Background The mammalian retina is a valuable model system to study neuronal biology in health and disease. To obtain insight into intrinsic processes of the retina, great efforts are directed towards the identification and characterization of transcripts with functional relevance to this tissue. Results With the goal to assemble a first genome-wide reference transcriptome of the adult mammalian retina, referred to as the retinome, we have extracted 13,037 non-redundant annotated genes from nearly 500,000 published datasets on redundant retina/retinal pigment epithelium (RPE transcripts. The data were generated from 27 independent studies employing a wide range of molecular and biocomputational approaches. Comparison to known retina-/RPE-specific pathways and established retinal gene networks suggest that the reference retinome may represent up to 90% of the retinal transcripts. We show that the distribution of retinal genes along the chromosomes is not random but exhibits a higher order organization closely following the previously observed clustering of genes with increased expression. Conclusion The genome wide retinome map offers a rational basis for selecting suggestive candidate genes for hereditary as well as complex retinal diseases facilitating elaborate studies into normal and pathological pathways. To make this unique resource freely available we have built a database providing a query interface to the reference retinome 1.

  7. Abnormal levels of histone methylation in the retinas of diabetic rats are reversed by minocycline treatment

    DEFF Research Database (Denmark)

    Wang, Wenjun; Sidoli, Simone; Zhang, Wenquan

    2017-01-01

    67% of these marks had their relative abundance restored to non-diabetic levels after minocycline treatment. Mono-and di-methylation states of histone H4 lysine 20 (H4K20me1/me2), markers related to DNA damage response, were found to be up-regulated in the retinas of diabetic rats and restored......In this study we quantified the alterations of retinal histone post-translational modifications (PTMs) in diabetic rats using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach. Some diabetic rats were subsequently treated with minocycline, a tetracycline antibiotic, which has...... been shown to inhibit the diabetes-induced chronic inflammation in the retinas of rodents. We quantified 266 differentially modified histone peptides, including 48 out of 83 methylation marks with significantly different abundancein retinas of diabetic rats as compared to non-diabetic controls. About...

  8. Sobre la terapia génica para enfermedades de la retina.

    Science.gov (United States)

    Fischer, M Dominik

    2017-07-11

    Las mutaciones en un gran número de genes provocan degeneración de la retina y ceguera sin que exista actualmente cura alguna. En las últimas décadas, la terapia génica para enfermedades de la retina ha evolucionado y se ha convertido en un nuevo y prometedor paradigma terapéutico para estas enfermedades poco comunes. Este artículo refleja las ideas y los conceptos que parten de la ciencia básica hacia la aplicabilidad de la terapia génica en el ámbito clínico. Se describen los avances y las reflexiones actuales sobre la eficacia de los ensayos clínicos en la actualidad y se discuten los posibles obstáculos y soluciones de cara al futuro de la terapia génica para enfermedades de la retina. © 2017 S. Karger AG, Basel.

  9. Testbeam results of the first real-time embedded tracking system with artificial retina

    Energy Technology Data Exchange (ETDEWEB)

    Neri, N., E-mail: nicola.neri@mi.infn.it; Abba, A.; Caponio, F.; Citterio, M.; Coelli, S.; Fu, J.; Merli, A.; Monti, M.; Petruzzo, M.

    2017-02-11

    We present the testbeam results of the first real-time embedded tracking system based on artificial retina algorithm. The tracking system prototype is capable of fast track reconstruction with a latency of the response below 1 μs and track parameter resolutions that are comparable with the offline results. The artificial retina algorithm was implemented in hardware in a custom data acquisition board based on commercial FPGA. The system was tested successfully using a 180 GeV/c proton beam at the CERN SPS with a maximum track rate of about 280 kHz. Online track parameters were found in good agreement with offline results and with the simulated response. - Highlights: • First real-time tracking system based on artificial retina algorithm tested on beam. • Fast track reconstruction within one microsecond latency and offline like quality. • Fast tracking algorithm implemented in commercial FPGAs.

  10. Ontogenetic expression of the Otx2 and Crx homeobox genes in the retina of the rat

    DEFF Research Database (Denmark)

    Rath, Martin F; Morin, Fabrice; Shi, Qiong

    2007-01-01

    . This confirmed the presence of Otx2 mRNA in both the embryonic retinal pigment epithelium and the developing neural retina. During development, the expression of Otx2 persists in the pigment epithelium, whereas Otx2 expression of the neural retina becomes progressively restricted to the outer nuclear layer......Otx2 and Crx are vertebrate orthologs of the orthodenticle family of homeobox genes, which are involved in retinal development. In this study, the temporal expression patterns of Otx2 and Crx in the rat retina during embryonic and postnatal stages of development were analyzed in detail...... and the outer part of the inner nuclear layer. Immunohistochemistry revealed that Otx2 protein is also present in cell bodies of the ganglion cell layer, which does not contain the Otx2 transcript, suggesting that Otx2 protein is synthesized in cell bodies of the bipolar neurons and then transported...

  11. Training and professional profile of retinologists in Spain: Retina 2 project, Report 4

    Directory of Open Access Journals (Sweden)

    Pastor JC

    2011-04-01

    Full Text Available J Carlos Pastor1,3, Itziar Fernández2, Jimena Rojas1, Rosa Coco1, Maria R Sanabria1, Enrique Rodríguez-de la Rúa1,3, Diego Sánchez3, Carmen Valverde3, Anna Sala Puigdollers1,31University Institute of Applied Ophthalmobiology (IOBA, Retina Group, 2Ministry of Science and Innovation CIBER-BBN, Statistics Department, 3Clinic University Hospital, University of Valladolid, Valladolid, SpainBackground: Uniform postresidency systems to train medical specialists have not been developed in most European countries. Before developing a framework for such a system, we established the learning and professional profiles of Spanish ophthalmologists dedicated to medical retina and vitreoretina subspecialties.Methods: After identification of presumed subspecialists by experts from different autonomous regions, a self-administered questionnaire was mailed in 2006. A reminder was sent three weeks later. Postal mail was used. Nonresponder bias was determined.Results: Of 492 possible retina subspecialists, 261 replied to the questionnaires. While about 86% received specific retinal training, standardized fellowship programs were uncommon for both medical retina and vitreoretina (around 10%. Of the responders, 24.5% performed only medical retina, 11.8% vitreoretina, and 63.6% both. Most (60.5% practiced anterior segment surgery, and 78.7% declared skills in vitrectomy.Conclusion: We have developed a database of Spanish ophthalmologists dedicated to retinal pathologies and identified some characteristics of their professional profile. Although most of them have received specific retinal training, standardized mastership programs are still uncommon. These data will be useful in creating a standardized Retina Mastership, an important goal of the European Higher Education Area.Keywords: clinical activity, fellowship, mastership, professional profile, retinologist training

  12. Cell therapeutics to treat diseases of the retina

    Directory of Open Access Journals (Sweden)

    Natarajan S

    2008-11-01

    Full Text Available Background: The adult Bone Marrow Stem Cells (BMSCs have distinct advantages over the other types of stem cells. They are multipotent, can be stored for upto 10 years and considered to be one of the best sources of hematopoietic and mesenchymal stem cells in an adult body. Genetically inherited diseases such as Retinitis Pigmentosa and Degenerative diseases such as Age Related Macular Degeneration remain unsolved as no definitive treatment is available to repair the damages caused to the RPE and Photoreceptors as of now. In this scenario, the technique of Bone Marrow aspiration & isolation of Mono Nucleated Cells (MNCs & intra-vitreal injection of a very small volume of MNCs in human retinal disorders has been standardized and is safe and feasible for human studies (Mohanty et al and autotransplantation of RPEs from periphery to affected area are underpractice(Coffey et al. In this study we report our research work on different approaches to the above diseases using cell therapeuticsStudy 1 Materials & methods: Ciliary Pigment Epithelium was harvested from donor eyes from Aditya Jyot Eye Hospital, Mumbai and was taken to and grown at NCRM lab. The cells were grown in the earlier reported methodology of Brenda et al (Science 2004. Results: The CPE derived Retinal stem cells grew well in the lab. However, the practical difficulties of harvesting the same in patients limited our further steps in this study. Study II:? Materials & methods: Cadaver eye RPE cells were harvested and grown using polymer scaffolds after transporting them over 6 to 12 Hrs. The RPEs were grown on conventional methods and in polymer scaffolds and were subjected to RT-PCR. Results: Human RPEs were able to grow without amniotic membrane and the same was proven by RT-PCR. This would make it possible for the peripheral RPEs taken from patients to be stored and later expanded and used for replacing the diseased cells of the central portion of the retina in future, without having

  13. Peripheral Avascular Retina in a Term Male Neonate With Microvillus Inclusion Disease and Pancreatic Insufficiency.

    Science.gov (United States)

    Paulus, Yannis M; Alcorn, Deborah M; Gaynon, Michael; Moshfeghi, Darius M

    2015-05-01

    The authors present the first case of peripheral avascular retina in a term male neonate with pancreatic exocrine insufficiency, atypical microvillus inclusion disease, flat tympanograms, and recurrent urinary tract infections. Clinical examination showed avascular peripheral retina to posterior zone II temporally, with a flat stage 1-like demarcation line, and no plus disease. Genetic testing results were normal. The patient developed peripheral neovascularization and underwent panretinal photocoagulation. This case likely represents mild Norrie disease, familial exudative vitreoretinopathy, or incontinentia pigmenti due to a Wnt signaling abnormality. While these conditions are usually more severe, a variable spectrum of Wnt abnormalities exists throughout the body. Copyright 2015, SLACK Incorporated.

  14. Msx1 is expressed in retina endothelial cells at artery branching sites

    OpenAIRE

    Miguel Lopes; Olivier Goupille; Cécile Saint Cloment; Benoît Robert

    2012-01-01

    Summary Msx1 and Msx2 encode homeodomain transcription factors that play a role in several embryonic developmental processes. Previously, we have shown that in the adult mouse, Msx1lacZ is expressed in vascular smooth muscle cells (VSMCs) and pericytes, and that Msx2lacZ is also expressed in VSMCs as well as in a few endothelial cells (ECs). The mouse retina and choroid are two highly vascularized tissues. Vessel alterations in the retina are associated with several human diseases and the ret...

  15. Simultaneous in vivo imaging of melanin and lipofuscin in the retina with multimodal photoacoustic ophthalmoscopy

    Science.gov (United States)

    Zhang, Xiangyang; Zhang, Hao F.; Zhou, Lixiang; Jiao, Shuliang

    2012-02-01

    We combined photoacoustic ophthalmoscopy (PAOM) with autofluorescence imaging for simultaneous in vivo imaging of dual molecular contrasts in the retina using a single light source. The dual molecular contrasts come from melanin and lipofuscin in the retinal pigment epithelium (RPE). Melanin and lipofuscin are two types of pigments and are believed to play opposite roles (protective vs. exacerbate) in the RPE in the aging process. We successfully imaged the retina of pigmented and albino rats at different ages. The experimental results showed that multimodal PAOM system can be a potentially powerful tool in the study of age-related degenerative retinal diseases.

  16. Photonic crystal light collectors in fish retina improve vision in turbid water.

    Science.gov (United States)

    Kreysing, Moritz; Pusch, Roland; Haverkate, Dorothee; Landsberger, Meik; Engelmann, Jacob; Ruiter, Janina; Mora-Ferrer, Carlos; Ulbricht, Elke; Grosche, Jens; Franze, Kristian; Streif, Stefan; Schumacher, Sarah; Makarov, Felix; Kacza, Johannes; Guck, Jochen; Wolburg, Hartwig; Bowmaker, James K; von der Emde, Gerhard; Schuster, Stefan; Wagner, Hans-Joachim; Reichenbach, Andreas; Francke, Mike

    2012-06-29

    Despite their diversity, vertebrate retinae are specialized to maximize either photon catch or visual acuity. Here, we describe a functional type that is optimized for neither purpose. In the retina of the elephantnose fish (Gnathonemus petersii), cone photoreceptors are grouped together within reflecting, photonic crystal-lined cups acting as macroreceptors, but rod photoreceptors are positioned behind these reflectors. This unusual arrangement matches rod and cone sensitivity for detecting color-mixed stimuli, whereas the photoreceptor grouping renders the fish insensitive to spatial noise; together, this enables more reliable flight reactions in the fish's dim and turbid habitat as compared with fish lacking this retinal specialization.

  17. Modelación y simulación de la retina humana

    OpenAIRE

    Andrés Castaño; Camilo Montenegro; Carlos Molina; Sergio Mejía

    2001-01-01

    Las enfermedades de la retina causan pérdida de la visión de varios
    grados de severidad; las causas son múltiples y en la mayoría de los casos irreversibles. En los últimos años se ha venido desarrollando investigación en el campo de la visión artificial y la visión por computador, alrededor de todo el mundo. Nuestro proyecto pretende desarrollar un modelo matemático de la retina, implementar la solución numérica en MATLAB™ y posteriormente construir un dispositivo electró...

  18. Cellular disturbance in the rats retina after irradiation and metabolic errors during the postnatal period

    International Nuclear Information System (INIS)

    Lierse, W.; Franke, H.D.

    1982-01-01

    During the first five days of the postnatal period the retina has been vulnerable following administration of DNA blocking drugs and irradiation with conventional X-rays and fast neutrons. During this period the disturbance of lamination accompanied with pycnosis of neurons and neuroblasts has been the important morphologic reaction. During the same phase metabolic errors, like experimental phenylketonuria, have produced a swelling of photoreceptor cells and pigmentepithelium cells. The other neurons of the retina were pycnotic. Structural alterations like rosettes persisted during the rest of life. The relative minor error during the first phase of rats life may result in a persistent disease. (orig.)

  19. Nutritional manipulation of primate retinas, III: Effects of lutein or zeaxanthin supplementation on adipose tissue and retina of xanthophyll-free monkeys.

    Science.gov (United States)

    Johnson, Elizabeth J; Neuringer, Martha; Russell, Robert M; Schalch, Wolfgang; Snodderly, D Max

    2005-02-01

    Macular pigment (MP) is composed of the xanthophylls lutein (L) and zeaxanthin (Z) and may help to prevent age-related macular degeneration or retard its progression. In this study the effects of L or Z supplementation on carotenoid levels was examined in serum, adipose tissue, and retina in rhesus monkeys with no previous intake of xanthophylls. From birth to 7 to 16 years of age, 18 rhesus monkeys were fed semipurified diets containing all essential nutrients but no xanthophylls. Six were supplemented with pure L and 6 with pure Z at 3.9 micromol/kg per day for 24 to 101 weeks. At baseline and at 4- to 12-week intervals, carotenoids in adipose tissue were measured by HPLC. At study completion, carotenoids in serum and retina (central 4 mm, 8-mm annulus, and the periphery) were determined. Results were compared with data from control monkeys fed a standard laboratory diet. Monkeys fed xanthophyll-free diets had no L or Z in serum or tissues. After L or Z supplementation, serum and adipose tissue concentrations significantly increased in the supplemented groups. Both L and 3R,3'S-Z (RSZ or meso-Z, not present in the diet) were incorporated into retinas of monkeys supplemented with L, with RSZ present only in the macula (central 4 mm). All-trans Z, but no RSZ, accumulated in retinas of monkeys supplemented with Z. L is the precursor of RSZ, a major component of macular pigment. Xanthophyll-free monkeys can accumulate retinal xanthophylls and provide a valuable model for examining their uptake and conversion.

  20. Tratamento da instabilidade lombar com parafusos pediculares Treatment of lumbar instability with pedicular screws

    Directory of Open Access Journals (Sweden)

    Osmar Avanzi

    2005-01-01

    Full Text Available A instabilidade lombar é uma doença freqüente na prática clínica. Vários autores preconizam o uso de parafusos pediculares para fixação da artrodese posterior, demonstrando melhores resultados do que a estabilização in situ. OBJETIVO: Avaliar o resultado funcional e radiográfico dos pacientes que procuraram o Grupo de Coluna da Faculdade de Ciências Médicas da Santa Casa de São Paulo portadores de instabilidade lombar submetidos ao tratamento cirúrgico pela artrodese vertebral por via posterior utilizando-se fixação metálica representada por parafusos pediculares. MÉTODOS: Foram coletados dados dos prontuários médicos do Serviço de Arquivos Médicos (S.A.M.E da Irmandade da Santa Casa de Misericórdia de São Paulo e avaliação por meio de radiografias simples nas incidências frente, perfil e oblíquas para estudos de imagem além da avaliação funcional pré e pós-operatória, com seguimento mínimo de dois anos. RESULTADOS: Durante o período de Novembro de 1995 à Junho de 2000 avaliamos dez pacientes portadores de instabilidade lombar degenerativa (48%, cinco pacientes com espondilolistese ístmica (23% e seis com estenose lombar degenerativa (29%. Quanto à avaliação funcional, obtivemos 76% de resultados excelentes e bons. As complicações verificadas foram infecção superficial, pseudartrose e posicionamento inadequado dos parafusos (19%. CONCLUSÕES: Os autores concluem que este método de fixação é eficaz, apresentando fusão da artrodese em 95% dos pacientes.The lumbar instability is a common desease in clinical practice. Several authors recommend the use of pedicular screws as a fixation system for posterior arthodesis since they provide better results compared to in situ stabilization. Objective: to evaluate the functional and radiographic results in patients assisted by the Spine Group of the Medical Sciences School of Santa Casa of São Paulo, presenting lumbar instability and who underwent

  1. Quantitative analysis of retina layer elasticity based on automatic 3D segmentation (Conference Presentation)

    Science.gov (United States)

    He, Youmin; Qu, Yueqiao; Zhang, Yi; Ma, Teng; Zhu, Jiang; Miao, Yusi; Humayun, Mark; Zhou, Qifa; Chen, Zhongping

    2017-02-01

    Age-related macular degeneration (AMD) is an eye condition that is considered to be one of the leading causes of blindness among people over 50. Recent studies suggest that the mechanical properties in retina layers are affected during the early onset of disease. Therefore, it is necessary to identify such changes in the individual layers of the retina so as to provide useful information for disease diagnosis. In this study, we propose using an acoustic radiation force optical coherence elastography (ARF-OCE) system to dynamically excite the porcine retina and detect the vibrational displacement with phase resolved Doppler optical coherence tomography. Due to the vibrational mechanism of the tissue response, the image quality is compromised during elastogram acquisition. In order to properly analyze the images, all signals, including the trigger and control signals for excitation, as well as detection and scanning signals, are synchronized within the OCE software and are kept consistent between frames, making it possible for easy phase unwrapping and elasticity analysis. In addition, a combination of segmentation algorithms is used to accommodate the compromised image quality. An automatic 3D segmentation method has been developed to isolate and measure the relative elasticity of every individual retinal layer. Two different segmentation schemes based on random walker and dynamic programming are implemented. The algorithm has been validated using a 3D region of the porcine retina, where individual layers have been isolated and analyzed using statistical methods. The errors compared to manual segmentation will be calculated.

  2. Histologic correlation of in vivo optical coherence tomography images of the human retina

    NARCIS (Netherlands)

    Chen, T.; Cense, B.; Miller, J.S.; Rubin, P. A. D.; Deschler, D. G.; Gragoudas, E. S.; de Boer, J.F.

    2006-01-01

    Purpose: To correlate in vivo human retina optical coherence tomography (OCT)3 images with histology. Design: Case series. Methods: Linear OCT3 scans through the macula and optic nerve were obtained in three eyes of three patients who then underwent exenteration surgery for orbital cancers. OCT3

  3. Photopic spectral sensitivities of the red and the yellow field of the pigeon retina

    NARCIS (Netherlands)

    Wortel, J.F.; Wubbels, R.J.; Nuboer, J.F.W.

    1984-01-01

    The spectral sensitivities of the red field and the yellow field in the retina of the homing pigeon (Columba Livia) were determined on the basis of ERG responses. Between 450 and 550 nm the relative spectral sensitivity of the yellow field turned out to be higher than that of the red field. The

  4. Müller cells express the cannabinoid CB2 receptor in the vervet monkey retina

    DEFF Research Database (Denmark)

    Bouskila, Joseph; Javadi, Pasha; Casanova, Christian

    2013-01-01

    The presence of the cannabinoid receptor type 1 (CB1R) has been largely documented in the rodent and primate retinae in recent years. There is, however, some controversy concerning the presence of the CB2 receptor (CB2R) within the central nervous system. Only recently, CB2R has been found in the...

  5. Bipolar cell gap junctions serve major signaling pathways in the human retina.

    Science.gov (United States)

    Kántor, Orsolya; Varga, Alexandra; Nitschke, Roland; Naumann, Angela; Énzsöly, Anna; Lukáts, Ákos; Szabó, Arnold; Németh, János; Völgyi, Béla

    2017-08-01

    Connexin36 (Cx36) constituent gap junctions (GJ) throughout the brain connect neurons into functional syncytia. In the retina they underlie the transmission, averaging and correlation of signals prior conveying visual information to the brain. This is the first study that describes retinal bipolar cell (BC) GJs in the human inner retina, whose function is enigmatic even in the examined animal models. Furthermore, a number of unique features (e.g. fovea, trichromacy, midget system) necessitate a reexamination of the animal model results in the human retina. Well-preserved postmortem human samples of this study are allowed to identify Cx36 expressing BCs neurochemically. Results reveal that both rod and cone pathway interneurons display strong Cx36 expression. Rod BC inputs to AII amacrine cells (AC) appear in juxtaposition to AII GJs, thus suggesting a strategic AII cell targeting by rod BCs. Cone BCs serving midget, parasol or koniocellular signaling pathways display a wealth of Cx36 expression to form homologously coupled arrays. In addition, they also establish heterologous GJ contacts to serve an exchange of information between parallel signaling streams. Interestingly, a prominent Cx36 expression was exhibited by midget system BCs that appear to maintain intimate contacts with bistratified BCs serving other pathways. These findings suggest that BC GJs in parallel signaling streams serve both an intra- and inter-pathway exchange of signals in the human retina.

  6. Correlations between specific patterns of spontaneous activity and stimulation efficiency in degenerated retina.

    Directory of Open Access Journals (Sweden)

    Christine Haselier

    Full Text Available Retinal prostheses that are currently used to restore vision in patients suffering from retinal degeneration are not adjusted to the changes occurring during the remodeling process of the retina. Recent studies revealed abnormal rhythmic activity in the retina of genetic mouse models of retinitis pigmentosa. Here we describe this abnormal activity also in a pharmacologically-induced (MNU mouse model of retinal degeneration. To investigate how this abnormal activity affects the excitability of retinal ganglion cells, we recorded the electrical activity from whole mounted retinas of rd10 mice and MNU-treated mice using a microelectrode array system and applied biphasic current pulses of different amplitude and duration to stimulate ganglion cells electrically. We show that the electrical stimulation efficiency is strongly reduced in degenerated retinas, in particular when abnormal activity such as oscillations and rhythmic firing of bursts of action potentials can be observed. Using a prestimulus pulse sequence, we could abolish rhythmic retinal activity. Under these conditions, the stimulation efficiency was enhanced in a few cases but not in the majority of tested cells. Nevertheless, this approach supports the idea that modified stimulation protocols could help to improve the efficiency of retinal prostheses in the future.

  7. Lateral feedback from monophasic horizontal cells to cones in carp retina. I. Experiments

    NARCIS (Netherlands)

    Kamermans, M.; van Dijk, B. W.; Spekreijse, H.; Zweypfenning, R. C.

    1989-01-01

    The spatial and color coding of the monophasic horizontal cells were studied in light- and dark-adapted retinae. Slit displacement experiments revealed differences in integration area for the different cone inputs of the monophasic horizontal cells. The integration area measured with a 670-nm

  8. Adaptive colour contrast coding in the salamander retina efficiently matches natural scene statistics.

    Directory of Open Access Journals (Sweden)

    Genadiy Vasserman

    Full Text Available The visual system continually adjusts its sensitivity to the statistical properties of the environment through an adaptation process that starts in the retina. Colour perception and processing is commonly thought to occur mainly in high visual areas, and indeed most evidence for chromatic colour contrast adaptation comes from cortical studies. We show that colour contrast adaptation starts in the retina where ganglion cells adjust their responses to the spectral properties of the environment. We demonstrate that the ganglion cells match their responses to red-blue stimulus combinations according to the relative contrast of each of the input channels by rotating their functional response properties in colour space. Using measurements of the chromatic statistics of natural environments, we show that the retina balances inputs from the two (red and blue stimulated colour channels, as would be expected from theoretical optimal behaviour. Our results suggest that colour is encoded in the retina based on the efficient processing of spectral information that matches spectral combinations in natural scenes on the colour processing level.

  9. Expression of Endoplasmic Reticulum Stress-Related Factors in the Retinas of Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Shu Yan

    2012-01-01

    Full Text Available Recent reports show that ER stress plays an important role in diabetic retinopathy (DR, but ER stress is a complicated process involving a network of signaling pathways and hundreds of factors, What factors involved in DR are not yet understood. We selected 89 ER stress factors from more than 200, A rat diabetes model was established by intraperitoneal injection of streptozotocin (STZ. The expression of 89 ER stress-related factors was found in the retinas of diabetic rats, at both 1- and 3-months after development of diabetes, by quantitative real-time polymerase chain reaction arrays. There were significant changes in expression levels of 13 and 12 ER stress-related factors in the diabetic rat retinas in the first and third month after the development of diabetes, Based on the array results, homocysteine- inducible, endoplasmic reticulum stress-inducible, ubiquitin-like domain member 1(HERP, and synoviolin(HRD1 were studied further by immunofluorescence and Western blot. Immunofluorescence and Western blot analyses showed that the expression of HERP was reduced in the retinas of diabetic rats in first and third month. The expression of Hrd1 did not change significantly in the retinas of diabetic rats in the first month but was reduced in the third month.

  10. Ocular distribution of antioxidant enzyme paraoxonase & its alteration in cataractous lens & diabetic retina

    Directory of Open Access Journals (Sweden)

    Subramaniam Rajesh Bharathidevi

    2017-01-01

    Interpretation & conclusions: Distribution of PON enzyme and its activity in ocular tissues is reported here. The study revealed maximal PON activity in lens and retina, which are prone to higher oxidative stress. Differential activities of PON were observed in the lens and retinal tissues from cataractous and diabetic patients, respectively.

  11. Spatial organization of lipids in the human retina and optic nerve by MALDI imaging mass spectrometry.

    Science.gov (United States)

    Zemski Berry, Karin A; Gordon, William C; Murphy, Robert C; Bazan, Nicolas G

    2014-03-01

    MALDI imaging mass spectrometry (IMS) was used to characterize lipid species within sections of human eyes. Common phospholipids that are abundant in most tissues were not highly localized and observed throughout the accessory tissue, optic nerve, and retina. Triacylglycerols were highly localized in accessory tissue, whereas sulfatide and plasmalogen glycerophosphoethanolamine (PE) lipids with a monounsaturated fatty acid were found enriched in the optic nerve. Additionally, several lipids were associated solely with the inner retina, photoreceptors, or retinal pigment epithelium (RPE); a plasmalogen PE lipid containing DHA (22:6), PE(P-18:0/22:6), was present exclusively in the inner retina, and DHA-containing glycerophosphatidylcholine (PC) and PE lipids were found solely in photoreceptors. PC lipids containing very long chain (VLC)-PUFAs were detected in photoreceptors despite their low abundance in the retina. Ceramide lipids and the bis-retinoid, N-retinylidene-N-retinylethanolamine, was tentatively identified and found only in the RPE. This MALDI IMS study readily revealed the location of many lipids that have been associated with degenerative retinal diseases. Complex lipid localization within retinal tissue provides a global view of lipid organization and initial evidence for specific functions in localized regions, offering opportunities to assess their significance in retinal diseases, such as macular degeneration, where lipids have been implicated in the disease process.

  12. Interaction between the soma and the axon terminal of horizontal cells in carp retina

    NARCIS (Netherlands)

    Kamermans, M.; van Dijk, B. W.; Spekreijse, H.

    1990-01-01

    In teleost retina, the receptive fields of horizontal cell axon terminals have a larger space constant than the receptive fields of the horizontal cell somata. Generally this difference in receptive field size is attributed to the cell coupling which is assumed to be stronger in the horizontal axon

  13. Circadian expression of clock genes and clock-controlled genes in the rat retina

    NARCIS (Netherlands)

    Kamphuis, Willem; Cailotto, Cathy; Dijk, Frederike; Bergen, Arthur; Buijs, Ruud M.

    2005-01-01

    The circadian expression patterns of genes encoding for proteins that make up the core of the circadian clock were measured in rat retina using real-time quantitative PCR (qPCR). Transcript levels of several genes previously used for normalization of qPCR assays were determined and the effect of

  14. A Perspective on the Müller Cell-Neuron Metabolic Partnership in the Inner Retina

    DEFF Research Database (Denmark)

    Toft-Kehler, A K; Skytt, D M; Kolko, Miriam

    2017-01-01

    between the vessels and neurons, Müller cells are responsible for the functional and metabolic support of the surrounding neurons. As a consequence of major energy demands in the retina, high levels of glucose are consumed and processed by Müller cells. The present review provides a perspective...

  15. Expression and Function of the Endocannabinoid System in the Retina and the Visual Brain

    Directory of Open Access Journals (Sweden)

    Jean-François Bouchard

    2016-01-01

    Full Text Available Endocannabinoids are important retrograde modulators of synaptic transmission throughout the nervous system. Cannabinoid receptors are seven transmembrane G-protein coupled receptors favoring Gi/o protein. They are known to play an important role in various processes, including metabolic regulation, craving, pain, anxiety, and immune function. In the last decade, there has been a growing interest for endocannabinoids in the retina and their role in visual processing. The purpose of this review is to characterize the expression and physiological functions of the endocannabinoid system in the visual system, from the retina to the primary visual cortex, with a main interest regarding the retina, which is the best-described area in this system so far. It will show that the endocannabinoid system is widely present in the retina, mostly in the through pathway where it can modulate neurotransmitter release and ion channel activity, although some evidence also indicates possible mechanisms via amacrine, horizontal, and Müller cells. The presence of multiple endocannabinoid ligands, synthesizing and catabolizing enzymes, and receptors highlights various pharmacological targets for novel therapeutic application to retinal diseases.

  16. A Comparative Analysis of the Endocannabinoid System in the Retina of Mice, Tree Shrews, and Monkeys

    DEFF Research Database (Denmark)

    Bouskila, Joseph; Javadi, Pasha; Elkrief, Laurent

    2016-01-01

    is known about the distribution of the enzymes involved in the synthesis and degradation of these eCBs. We therefore examined the expression and localization of the main components of the eCB system in the retina of mice, tree shrews, and monkeys. We found that CB1R and FAAH distributions are well...

  17. Human cadaver retina model for retinal heating during corneal surgery with a femtosecond laser

    Science.gov (United States)

    Sun, Hui; Fan, Zhongwei; Yun, Jin; Zhao, Tianzhuo; Yan, Ying; Kurtz, Ron M.; Juhasz, Tibor

    2014-02-01

    Femtosecond lasers are widely used in everyday clinical procedures to perform minimally invasive corneal refractive surgery. The intralase femtosecond laser (AMO Corp. Santa Ana, CA) is a common example of such a laser. In the present study a numerical simulation was developed to quantify the temperature rise in the retina during femtosecond intracorneal surgery. Also, ex-vivo retinal heating due to laser irradiation was measured with an infrared thermal camera (Fluke Corp. Everett, WA) as a validation of the simulation. A computer simulation was developed using Comsol Multiphysics to calculate the temperature rise in the cadaver retina during femtosecond laser corneal surgery. The simulation showed a temperature rise of less than 0.3 degrees for realistic pulse energies for the various repetition rates. Human cadaver retinas were irradiated with a 150 kHz Intralase femtosecond laser and the temperature rise was measured withan infrared thermal camera. Thermal camera measurements are in agreement with the simulation. During routine femtosecond laser corneal surgery with normal clinical parameters, the temperature rise is well beneath the threshold for retina damage. The simulation predictions are in agreement with thermal measurements providing a level of experimental validation.

  18. The retina of Spalax ehrenbergi: novel histologic features supportive of a modified photosensory role.

    NARCIS (Netherlands)

    Cernuda-Cernuda, R.; Grip, W.J. de; Cooper, H.M.; Nevo, E.; Garcia-Fernandez, J.M.

    2002-01-01

    PURPOSE: The retina of the blind mole rat Spalax ehrenbergi was compared with other vertebrate photosensitive organs in an attempt to correlate its histologic organization with a presumptive nonvisual photoreceptor role. METHODS: The eyes of eight adult animals were analyzed by light and electron

  19. Curcumin Delays Retinal Degeneration by Regulating Microglia Activation in the Retina of rd1 Mice.

    Science.gov (United States)

    Wang, Yanhe; Yin, Zhiyuan; Gao, Lixiong; Sun, Dayu; Hu, Xisu; Xue, Langyue; Dai, Jiaman; Zeng, YuXiao; Chen, Siyu; Pan, Boju; Chen, Min; Xie, Jing; Xu, Haiwei

    2017-01-01

    Retinitis pigmentosa (RP) is characterized by degeneration of photoreceptors, and there are currently no effective treatments for this disease. However, curcumin has shown neuroprotectant efficacy in a RP rat and swine model, and thus, may have neuroprotective effects in this disease. Immunofluorescence staining, electroretinogram recordings, and behavioral tests were used to analyze the effects of curcumin and the underlying mechanism in retinal degeneration 1 (rd1) mice. The number of apoptotic cells in the retina of rd1 mice at postnatal day 14 significantly decreased with curcumin treatment and visual function was improved. The activation of microglia and secretion of chemokines and matrix metalloproteinases in the retina were inhibited by curcumin. These effects were also observed in a co-culture of BV2 microglial cells and retina-derived 661W cells. Curcumin delayed retinal degeneration by suppressing microglia activation in the retina of rd1 mice. Thus, it may be an effective treatment for neurodegenerative disorders such as RP. © 2017 The Author(s). Published by S. Karger AG, Basel.

  20. Curcumin Delays Retinal Degeneration by Regulating Microglia Activation in the Retina of rd1 Mice

    Directory of Open Access Journals (Sweden)

    Yanhe Wang

    2017-11-01

    Full Text Available Background/Aims: Retinitis pigmentosa (RP is characterized by degeneration of photoreceptors, and there are currently no effective treatments for this disease. However, curcumin has shown neuroprotectant efficacy in a RP rat and swine model, and thus, may have neuroprotective effects in this disease. Methods: Immunofluorescence staining, electroretinogram recordings, and behavioral tests were used to analyze the effects of curcumin and the underlying mechanism in retinal degeneration 1 (rd1 mice. Results: The number of apoptotic cells in the retina of rd1 mice at postnatal day 14 significantly decreased with curcumin treatment and visual function was improved. The activation of microglia and secretion of chemokines and matrix metalloproteinases in the retina were inhibited by curcumin. These effects were also observed in a co-culture of BV2 microglial cells and retina-derived 661W cells. Conclusions: Curcumin delayed retinal degeneration by suppressing microglia activation in the retina of rd1 mice. Thus, it may be an effective treatment for neurodegenerative disorders such as RP.

  1. Is adding a new class of cones to the retina sufficient to cure color-blindness?

    NARCIS (Netherlands)

    Cornelissen, F.W.; Brenner, E.

    2015-01-01

    New genetic methods have made it possible to substitute cone pigments in the retinas of adult nonhuman primates. Doing so influences the animals' visual abilities, demonstrating that the gene therapy was effective. However, we argue that no studies conducted so far have unambiguously demonstrated

  2. Is adding a new class of cones to the retina sufficient to cure color-blindness?

    NARCIS (Netherlands)

    Cornelissen, Frans W.; Brenner, Eli

    New genetic methods have made it possible to substitute cone pigments in the retinas of adult nonhuman primates. Doing so influences the animals' visual abilities, demonstrating that the gene therapy was effective. However, we argue that no studies conducted so far have unambiguously demonstrated

  3. Chloride currents in cones modify feedback from horizontal cells to cones in goldfish retina

    NARCIS (Netherlands)

    Endeman, Duco; Fahrenfort, Iris; Sjoerdsma, Trijntje; Steijaert, Marvin; ten Eikelder, Huub; Kamermans, Maarten

    2012-01-01

    In neuronal systems, excitation and inhibition must be well balanced to ensure reliable information transfer. The cone/horizontal cell (HC) interaction in the retina is an example of this. Because natural scenes encompass an enormous intensity range both in temporal and spatial domains, the balance

  4. Simulated human eye retina adaptive optics imaging system based on a liquid crystal on silicon device

    International Nuclear Information System (INIS)

    Jiang Baoguang; Cao Zhaoliang; Mu Quanquan; Hu Lifa; Li Chao; Xuan Li

    2008-01-01

    In order to obtain a clear image of the retina of model eye, an adaptive optics system used to correct the wave-front error is introduced in this paper. The spatial light modulator that we use here is a liquid crystal on a silicon device instead of a conversional deformable mirror. A paper with carbon granule is used to simulate the retina of human eye. The pupil size of the model eye is adjustable (3-7 mm). A Shack–Hartman wave-front sensor is used to detect the wave-front aberration. With this construction, a value of peak-to-valley is achieved to be 0.086 λ, where λ is wavelength. The modulation transfer functions before and after corrections are compared. And the resolution of this system after correction (691p/m) is very close to the dirraction limit resolution. The carbon granule on the white paper which has a size of 4.7 μm is seen clearly. The size of the retina cell is between 4 and 10 mu;m. So this system has an ability to image the human eye's retina. (classical areas of phenomenology)

  5. Ultrasound-mediated nanoparticle delivery across ex vivo bovine retina after intravitreal injection.

    Science.gov (United States)

    Huang, Di; Chen, Ying-Shan; Thakur, Sachin S; Rupenthal, Ilva D

    2017-10-01

    Intravitreal injection is the most common administration route for the treatment of retinal diseases. However, the vitreous and some of the retinal layers themselves act as significant barriers to efficient delivery of drugs administered intravitreally. This study aimed to improve the diffusive mobility of nanoparticles (NPs) in the vitreous and enhance their permeation across the retina after intravitreal injection by application of ultrasound (US). Ex vivo posterior bovine eye cups were used and the vitreous was either left intact or removed gently from the neural retina. Hyaluronic acid coated human serum albumin NPs were administered into the eye cups and continuous US with a frequency of 1MHz, an intensity of 0.5W/cm 2 , and a duration of 30s was applied once or repeatedly via the transscleral route. After pre-determined time points, fluorescence intensities in the vitreous and the retina were analyzed. Short pulses of US significantly improved the diffusive mobility of NPs through the vitreous as well as their penetration across the neural retina into the retinal pigment epithelium and choroid without causing any detectable damage to the ocular tissues. Therefore, transscleral US could be a powerful and safe tool to enhance retinal delivery of intravitreally injected NPs. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Macular pigment carotenoids in the retina and occipital cortex are related in humans

    Science.gov (United States)

    Objectives: Lutein and zeaxanthin are dietary carotenoids that preferentially accumulate in the macular region of the retina. Together with mesozeaxanthin, a conversion product of lutein in the macula, they form the macular pigment. Lutein is also the predominant carotenoid in human brain tissue and...

  7. Immunocytochemical localization of the glutamate transporter GLT-1 in goldfish (Carassius auratus) retina

    NARCIS (Netherlands)

    Vandenbranden, C. A.; Yazulla, S.; Studholme, K. M.; Kamphuis, W.; Kamermans, M.

    2000-01-01

    Glutamate is the major excitatory neurotransmitter in the retina of vertebrates. Electrophysiological experiments in goldfish and salamander have shown that neuronal glutamate transporters play an important role in the clearance of glutamate from cone synaptic clefts. In this study, the localization

  8. Modulation of horizontal cell receptive fields in the light adapted goldfish retina

    NARCIS (Netherlands)

    Verweij, J.; Kamermans, M.; van den Aker, E. C.; Spekreijse, H.

    1996-01-01

    In the isolated goldfish retina, 700 nm background illumination increases the horizontal cell receptive field size, as measured with 565 nm slits of light, but decreases the receptive field size, when measured with 660 nm slits. These background-induced changes in receptive field size are absent

  9. Spectral sensitivity of the feedback signal from horizontal cells to cones in goldfish retina

    NARCIS (Netherlands)

    Kraaij, D. A.; Kamermans, M.; Spekreijse, H.

    1998-01-01

    The spectral sensitivity of cones in isolated goldfish retina was determined with whole-cell recording techniques. Three spectral classes of cones were found with maximal sensitivities around 620 nm, 540 nm, and 460 nm. UV-cones were not found because our stimulator did not allow effective

  10. Adaptive optics parallel spectral domain optical coherence tomography for imaging the living retina

    Science.gov (United States)

    Zhang, Yan; Rha, Jungtae; Jonnal, Ravi S.; Miller, Donald T.

    2005-06-01

    Although optical coherence tomography (OCT) can axially resolve and detect reflections from individual cells, there are no reports of imaging cells in the living human retina using OCT. To supplement the axial resolution and sensitivity of OCT with the necessary lateral resolution and speed, we developed a novel spectral domain OCT (SD-OCT) camera based on a free-space parallel illumination architecture and equipped with adaptive optics (AO). Conventional flood illumination, also with AO, was integrated into the camera and provided confirmation of the focus position in the retina with an accuracy of ±10.3 μm. Short bursts of narrow B-scans (100x560 μm) of the living retina were subsequently acquired at 500 Hz during dynamic compensation (up to 14 Hz) that successfully corrected the most significant ocular aberrations across a dilated 6 mm pupil. Camera sensitivity (up to 94 dB) was sufficient for observing reflections from essentially all neural layers of the retina. Signal-to-noise of the detected reflection from the photoreceptor layer was highly sensitive to the level of cular aberrations and defocus with changes of 11.4 and 13.1 dB (single pass) observed when the ocular aberrations (astigmatism, 3rd order and higher) were corrected and when the focus was shifted by 200 μm (0.54 diopters) in the retina, respectively. The 3D resolution of the B-scans (3.0x3.0x5.7 μm) is the highest reported to date in the living human eye and was sufficient to observe the interface between the inner and outer segments of individual photoreceptor cells, resolved in both lateral and axial dimensions. However, high contrast speckle, which is intrinsic to OCT, was present throughout the AO parallel SD-OCT B-scans and obstructed correlating retinal reflections to cell-sized retinal structures.

  11. Linezolid-induced optic neuropathy with a rare pathological change in the inner retina.

    Science.gov (United States)

    Ishii, Nobuhito; Kinouchi, Reiko; Inoue, Masatomo; Yoshida, Akitoshi

    2016-12-01

    We report a case of linezolid-induced optic neuropathy with transient microcystic spaces in the inner retina. We observed the retina using Fourier-domain optical coherence tomography (FD-OCT) in a patient with linezolid-induced optic neuropathy. A 49-year-old woman presented to our department with a 1-week history of bilateral photophobia. At the first visit, her best-corrected visual acuity (VA) was 0.6 in the right eye and 0.5 in the left eye. She had moderate optic disk edema and central scotomas bilaterally. FD-OCT showed bilateral microcystic spaces in the retina. Microcystic spaces were seen in the retinal nerve fiber layer (RNFL) and at the border of the RNFL and the retinal ganglion cell layer. Magnetic resonance imaging and laboratory tests showed no positive findings except for an elevated lactic acid level. One week after the first visit, the VA levels decreased to 0.06 and 0.07 in the right and left eyes, respectively. Because the patient had a 7-month history of linezolid treatment for persistent pyogenic arthritis, we suspected linezolid-induced optic neuropathy and immediately terminated treatment with this drug. The optic disk edema and the microcystic spaces in the retina resolved, and the VA improved to 1.2 at 6 weeks after linezolid withdrawal. Microcystic spaces, which resolved with linezolid withdrawal, were observed in linezolid-induced optic neuropathy. The microcystic spaces in the inner retina can be the first retinal sign of some optic neuropathies.

  12. Stereotyped Synaptic Connectivity Is Restored during Circuit Repair in the Adult Mammalian Retina.

    Science.gov (United States)

    Beier, Corinne; Palanker, Daniel; Sher, Alexander

    2018-06-04

    Proper function of the central nervous system (CNS) depends on the specificity of synaptic connections between cells of various types. Cellular and molecular mechanisms responsible for the establishment and refinement of these connections during development are the subject of an active area of research [1-6]. However, it is unknown if the adult mammalian CNS can form new type-selective synapses following neural injury or disease. Here, we assess whether selective synaptic connections can be reestablished after circuit disruption in the adult mammalian retina. The stereotyped circuitry at the first synapse in the retina, as well as the relatively short distances new neurites must travel compared to other areas of the CNS, make the retina well suited to probing for synaptic specificity during circuit reassembly. Selective connections between short-wavelength sensitive cone photoreceptors (S-cones) and S-cone bipolar cells provides the foundation of the primordial blue-yellow vision, common to all mammals [7-18]. We take advantage of the ground squirrel retina, which has a one-to-one S-cone-to-S-cone-bipolar-cell connection, to test if this connectivity can be reestablished following local photoreceptor loss [8, 19]. We find that after in vivo selective photoreceptor ablation, deafferented S-cone bipolar cells expand their dendritic trees. The new dendrites randomly explore the proper synaptic layer, bypass medium-wavelength sensitive cone photoreceptors (M-cones), and selectively synapse with S-cones. However, non-connected dendrites are not pruned back to resemble unperturbed S-cone bipolar cells. We show, for the first time, that circuit repair in the adult mammalian retina can recreate stereotypic selective wiring. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Post-translational processing of synaptophysin in the rat retina is disrupted by diabetes.

    Directory of Open Access Journals (Sweden)

    Travis S D'Cruz

    Full Text Available Synaptophysin, is an abundant presynaptic protein involved in synaptic vesicle recycling and neurotransmitter release. Previous work shows that its content is significantly reduced in the rat retina by streptozotocin (STZ-diabetes. This study tested the hypothesis that STZ-diabetes alters synaptophysin protein turnover and glycosylation in the rat retina. Whole explant retinas from male Sprague-Dawley rats were used in this study. Rats were made diabetic by a single intraperitoneal STZ injection (65 mg/kg body weight in 10 mM sodium citrate, pH 4.5. mRNA translation was measured using a (35S-methionine labeling assay followed by synaptophysin immunoprecipitation and autoradiography. A pulse-chase study was used to determine the depletion of newly synthesized synaptophysin. Depletion of total synaptophysin was determined after treatment with cycloheximide. Mannose rich N-glycosylated synaptophysin was detected by treating retinal lysates with endoglycosidase H followed by immunoblot analysis. Synaptophysin mRNA translation was significantly increased after 1 month (p<0.001 and 2 months (p<0.05 of STZ-diabetes, compared to age-matched controls. Newly synthesized synaptophysin degradation was significantly accelerated in the retina after 1 and 2 months of diabetes compared to controls (p<0.05. Mannose rich glycosylated synaptophysin was significantly increased after 1 month of STZ-diabetes compared to controls (p<0.05.These data suggest that diabetes increases mRNA translation of synaptophysin in the retina, resulting in an accumulation of mannose rich glycosylated synaptophysin, a transient post-translational state of the protein. This diabetes-induced irregularity in post-translational processing could explain the accelerated degradation of retinal synaptophysin in diabetes.

  14. Evaluation of the central macula in commotio retinae not associated with other types of traumatic retinopathy.

    Science.gov (United States)

    Park, Joo Youn; Nam, Woo Ho; Kim, Seung Hoon; Jang, Sun Young; Ohn, Young-Hoon; Park, Tae Kwann

    2011-08-01

    To report on the anatomical and functional changes to the macula in nine patients suffering from commotio retinae not accompanied by any other types of traumatic retinopathy. Nine injured eyes with commotio retinae were evaluated soon after ocular trauma with ophthalmic examination, including Spectral-domain optical coherence tomography (SD-OCT). In 12 eyes of 6 patients, Humphrey visual field (HVF) and multifocal electroretinogram (mfERG) were performed. Re-examinations were periodically performed for a mean of 26 days. Data from 9 injured eyes were collected and compared to data collected from the 9 non-affected eyes of the same patients. SD-OCT revealed no significant differences in the foveal thickness and total macular volume between traumatized and intact eyes in all 9 patients. Only 3 out of the 9 injured eyes showed abnormal findings in SD-OCT images such as discontinuity of the inner/outer segment (IS/OS) junction or abnormal hyper-reflectivity from the IS/OS and retinal pigment epithelium (RPE) lines in the macula. HVF and mfERG results did not show any functional deterioration in the injured eyes compared with intact eyes. During follow-up, the commotio retinae resolved in all 9 eyes. The changes to the outer retinal region detected in 3 patients by SD-OCT were also resolved. Acute retinal changes in commotio retinae, not associated with other retinal pathologies, were resolved without histological and functional sequelae. In a few cases of commotio retinae, SD-OCT revealed transient abnormalities mainly observed at the IS/OS and RPE complexes.

  15. Can Xanthophyll-Membrane Interactions Explain Their Selective Presence in the Retina and Brain?

    Science.gov (United States)

    Widomska, Justyna; Zareba, Mariusz; Subczynski, Witold Karol

    2016-01-01

    Epidemiological studies demonstrate that a high dietary intake of carotenoids may offer protection against age-related macular degeneration, cancer and cardiovascular and neurodegenerative diseases. Humans cannot synthesize carotenoids and depend on their dietary intake. Major carotenoids that have been found in human plasma can be divided into two groups, carotenes (nonpolar molecules, such as β-carotene, α-carotene or lycopene) and xanthophylls (polar carotenoids that include an oxygen atom in their structure, such as lutein, zeaxanthin and β-cryptoxanthin). Only two dietary carotenoids, namely lutein and zeaxanthin (macular xanthophylls), are selectively accumulated in the human retina. A third carotenoid, meso-zeaxanthin, is formed directly in the human retina from lutein. Additionally, xanthophylls account for about 70% of total carotenoids in all brain regions. Some specific properties of these polar carotenoids must explain why they, among other available carotenoids, were selected during evolution to protect the retina and brain. It is also likely that the selective uptake and deposition of macular xanthophylls in the retina and brain are enhanced by specific xanthophyll-binding proteins. We hypothesize that the high membrane solubility and preferential transmembrane orientation of macular xanthophylls distinguish them from other dietary carotenoids, enhance their chemical and physical stability in retina and brain membranes and maximize their protective action in these organs. Most importantly, xanthophylls are selectively concentrated in the most vulnerable regions of lipid bilayer membranes enriched in polyunsaturated lipids. This localization is ideal if macular xanthophylls are to act as lipid-soluble antioxidants, which is the most accepted mechanism through which lutein and zeaxanthin protect neural tissue against degenerative diseases. PMID:27030822

  16. Can Xanthophyll-Membrane Interactions Explain Their Selective Presence in the Retina and Brain?

    Directory of Open Access Journals (Sweden)

    Justyna Widomska

    2016-01-01

    Full Text Available Epidemiological studies demonstrate that a high dietary intake of carotenoids may offer protection against age-related macular degeneration, cancer and cardiovascular and neurodegenerative diseases. Humans cannot synthesize carotenoids and depend on their dietary intake. Major carotenoids that have been found in human plasma can be divided into two groups, carotenes (nonpolar molecules, such as β-carotene, α-carotene or lycopene and xanthophylls (polar carotenoids that include an oxygen atom in their structure, such as lutein, zeaxanthin and β-cryptoxanthin. Only two dietary carotenoids, namely lutein and zeaxanthin (macular xanthophylls, are selectively accumulated in the human retina. A third carotenoid, meso-zeaxanthin, is formed directly in the human retina from lutein. Additionally, xanthophylls account for about 70% of total carotenoids in all brain regions. Some specific properties of these polar carotenoids must explain why they, among other available carotenoids, were selected during evolution to protect the retina and brain. It is also likely that the selective uptake and deposition of macular xanthophylls in the retina and brain are enhanced by specific xanthophyll-binding proteins. We hypothesize that the high membrane solubility and preferential transmembrane orientation of macular xanthophylls distinguish them from other dietary carotenoids, enhance their chemical and physical stability in retina and brain membranes and maximize their protective action in these organs. Most importantly, xanthophylls are selectively concentrated in the most vulnerable regions of lipid bilayer membranes enriched in polyunsaturated lipids. This localization is ideal if macular xanthophylls are to act as lipid-soluble antioxidants, which is the most accepted mechanism through which lutein and zeaxanthin protect neural tissue against degenerative diseases.

  17. Effects of hyperbaric oxygen on crystalline lens and retina in nicotine-exposed rats.

    Science.gov (United States)

    Ari, Seyhmus; Nergiz, Yusuf; Cingü, Abdullah Kürşat; Atay, Ahmet Engin; Sahin, Alparslan; Cinar, Yasin; Caca, Ihsan

    2013-03-01

    To determine histopathological changes on crystalline lens and retina of rats after subcutaneous injection of nicotine and to examine the effects of hyperbaric oxygen (HBO) on these changes related to nicotine exposure. Twenty-eight female Sprague-Dawley rats were enrolled in the study and the rats were divided into four equal sized groups randomly (Group N: the rats exposed only to nicotine, group HB: the rats received only HBO, group N+HB: the rats that underwent to nicotine injection and subsequently received HBO, group C: the control group that neither exposed to nicotine nor received HBO). The rats were sacrificed by decapitation method and all were enucleated immediately after scarification. Tissue samples from crystalline lens, lens capsule, and the retina from the right eyes of the rats were examined by light microscopy. While the histological appearances of the retina and the lens was similar in group HB, group N+HB, and the control group; group N showed some pathological changes like decrement in the retinal ganglion cell density, atrophy of the retinal nerve fiber layer, congestion of the vessels in the optic nerve head, thinning of the internal plexiform layer, thinning of the lens capsule, and transformation of the anterior subcapsular epithelium into squamous epithelia. Subcutaneous injection of nicotine was found to be related with some pathological changes in the retina and lens of the Sprague-Dawley rats. However HBO caused no significant negative effect. Furthermore, the histopathological changes related to nicotine exposure in the lens and retina of the rats recovered by the application of HBO.

  18. Analysis of transcriptional regulatory pathways of photoreceptor genes by expression profiling of the Otx2-deficient retina.

    Science.gov (United States)

    Omori, Yoshihiro; Katoh, Kimiko; Sato, Shigeru; Muranishi, Yuki; Chaya, Taro; Onishi, Akishi; Minami, Takashi; Fujikado, Takashi; Furukawa, Takahisa

    2011-01-01

    In the vertebrate retina, the Otx2 transcription factor plays a crucial role in the cell fate determination of both rod and cone photoreceptors. We previously reported that Otx2 conditional knockout (CKO) mice exhibited a total absence of rods and cones in the retina due to their cell fate conversion to amacrine-like cells. In order to investigate the entire transcriptome of the Otx2 CKO retina, we compared expression profile of Otx2 CKO and wild-type retinas at P1 and P12 using microarray. We observed that expression of 101- and 1049-probe sets significantly decreased in the Otx2 CKO retina at P1 and P12, respectively, whereas, expression of 3- and 4149-probe sets increased at P1 and P12, respectively. We found that expression of genes encoding transcription factors involved in photoreceptor development, including Crx, Nrl, Nr2e3, Esrrb, and NeuroD, was markedly down-regulated in the Otx2 CKO at both P1 and P12. Furthermore, we identified three human retinal disease loci mapped in close proximity to certain down-regulated genes in the Otx2 CKO retina including Ccdc126, Tnfsf13 and Pitpnm1, suggesting that these genes are possibly responsible for these diseases. These transcriptome data sets of the Otx2 CKO retina provide a resource on developing rods and cones to further understand the molecular mechanisms underlying photoreceptor development, function and disease.

  19. Analysis of transcriptional regulatory pathways of photoreceptor genes by expression profiling of the Otx2-deficient retina.

    Directory of Open Access Journals (Sweden)

    Yoshihiro Omori

    Full Text Available In the vertebrate retina, the Otx2 transcription factor plays a crucial role in the cell fate determination of both rod and cone photoreceptors. We previously reported that Otx2 conditional knockout (CKO mice exhibited a total absence of rods and cones in the retina due to their cell fate conversion to amacrine-like cells. In order to investigate the entire transcriptome of the Otx2 CKO retina, we compared expression profile of Otx2 CKO and wild-type retinas at P1 and P12 using microarray. We observed that expression of 101- and 1049-probe sets significantly decreased in the Otx2 CKO retina at P1 and P12, respectively, whereas, expression of 3- and 4149-probe sets increased at P1 and P12, respectively. We found that expression of genes encoding transcription factors involved in photoreceptor development, including Crx, Nrl, Nr2e3, Esrrb, and NeuroD, was markedly down-regulated in the Otx2 CKO at both P1 and P12. Furthermore, we identified three human retinal disease loci mapped in close proximity to certain down-regulated genes in the Otx2 CKO retina including Ccdc126, Tnfsf13 and Pitpnm1, suggesting that these genes are possibly responsible for these diseases. These transcriptome data sets of the Otx2 CKO retina provide a resource on developing rods and cones to further understand the molecular mechanisms underlying photoreceptor development, function and disease.

  20. Segmentasi Pembuluh Darah Retina Pada Citra Fundus Menggunakan Gradient Based Adaptive Thresholding Dan Region Growing

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    Deni Sutaji

    2016-07-01

    Full Text Available AbstrakSegmentasi pembuluh darah pada citra fundus retina menjadi hal yang substansial dalam dunia kedokteran, karena dapat digunakan untuk mendeteksi penyakit, seperti: diabetic retinopathy, hypertension, dan cardiovascular. Dokter membutuhkan waktu sekitar dua jam untuk mendeteksi pembuluh darah retina, sehingga diperlukan metode yang dapat membantu screening agar lebih cepat.Penelitian sebelumnya mampu melakukan segmentasi pembuluh darah yang sensitif terhadap variasi ukuran lebar pembuluh darah namun masih terjadi over-segmentasi pada area patologi. Oleh karena itu, penelitian ini bertujuan untuk mengembangkan metode segmentasi pembuluh darah pada citra fundus retina yang dapat mengurangi over-segmentasi pada area patologi menggunakan Gradient Based Adaptive Thresholding dan Region Growing.Metode yang diusulkan terdiri dari 3 tahap, yaitu segmentasi pembuluh darah utama, deteksi area patologi dan segmentasi pembuluh darah tipis. Tahap segmentasi pembuluh darah utama menggunakan high-pass filtering dan tophat reconstruction pada kanal hijau citra yang sudah diperbaiki kontrasnya sehingga lebih jelas perbedaan antara pembuluh darah dan background. Tahap deteksi area patologi menggunakan metode Gradient Based Adaptive Thresholding. Tahap segmentasi pembuluh darah tipis menggunakan Region Growing berdasarkan informasi label pembuluh darah utama dan label area patologi. Hasil segmentasi pembuluh darah utama dan pembuluh darah tipis kemudian digabungkan sehingga menjadi keluaran sistem berupa citra biner pembuluh darah. Berdasarkan hasil uji coba, metode ini mampu melakukan segmentasi pembuluh darah retina dengan baik pada citra fundus DRIVE, yaitu dengan akurasi rata-rata 95.25% dan nilai Area Under Curve (AUC pada kurva Relative Operating Characteristic (ROC sebesar 74.28%.                           Kata Kunci: citra fundus retina, gradient based adaptive thresholding, patologi, pembuluh darah retina, region growing

  1. Effects of mercury intoxication on the response of horizontal cells of the retina of thraira fish (Hoplias malabaricus

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    C.L. Tanan

    2006-07-01

    Full Text Available Methyl mercury (MeHg is highly neurotoxic, affecting visual function in addition to other central nervous system functions. The effect of mercury intoxication on the amplitude of horizontal cell responses to light was studied in the retina of the fish Hoplias malabaricus. Intracellular responses were recorded from horizontal cells of fish previously intoxicated with MeHg by intraperitoneal injection (IP group or by trophic exposure (T group. Only one retina per fish was used. The doses of MeHg chloride administered to the IP group were 0.01, 0.05, 0.1, 1.0, 2.0, and 6.0 mg/kg. The amplitudes of the horizontal cell responses were lower than control in individuals exposed to 0.01 (N = 4 retinas, 0.05 (N = 2 retinas and 0.1 mg/kg (N = 1 retina, whereas no responses were recorded in the 1.0, 2.0, and 6.0 mg/kg groups. T group individuals were fed young specimens of Astyanax sp previously injected with MeHg corresponding to 0.75 (N = 1 retina, 0.075 (N = 8 retinas or 0.0075 (N = 4 retinas mg/kg fish body weight. After 14 doses, one every 5 days, the amplitude of the horizontal cell response was higher than control in individuals exposed to 0.075 and 0.0075 mg/kg, and lower in individuals exposed to 0.75 mg/kg. We conclude that intoxication with MeHg affects the electrophysiological response of the horizontal cells in the retina, either reducing or increasing its amplitude compared to control, and that these effects are related to the dose and/or to the mode of administration.

  2. Functional characterization of rs2229094 (T>C polymorphism in the tumor necrosis factor locus and lymphotoxin alpha expression in human retina: the Retina 4 project

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    Pastor-Idoate S

    2017-05-01

    Full Text Available Salvador Pastor-Idoate,1,2 Irene Rodríguez-Hernández,2,3 Jimena Rojas,1 Lucia Gonzalez-Buendia,1 Santiago Delgado-Tirado,1,4 Jose Carlos López,1 Rogelio González-Sarmiento,2,3 Jose C Pastor1,4 1IOBA Eye Institute, University of Valladolid, Valladolid, 2Molecular Medicine Unit, Department of Medicine, 3Molecular and Cellular Cancer Biology Institute, High Council of Scientific Research, Biomedical Research Institute of Salamanca, University of Salamanca, Salamanca, 4Department of Ophthalmology, Hospital Clínico Universitario, Valladolid, Spain Purpose: The objective of this study is to determine the expression and localization of lymphotoxin alpha (LTA in human retinas and the functionality of one of its polymorphisms rs2229094 (C13R (T>C, previously associated with proliferative vitreoretinopathy (PVR development.Materials and methods: Total RNA from three healthy human retinas were extracted and subjected to reverse transcription-polymerase chain reaction (RT-PCR analysis, using flanking primers of LTA cDNA. In addition, three human eyes with retinal detachment (RD and three healthy control eyes were subjected to immunohistochemistry (IHC with a specific antibody against LTA. The functionality of T and C alleles was assessed by using pCEFL-Flag expression vector and transient transfection assays in COS-1 cell line. In addition, expression analysis by RT-PCR, Western blot and subcellular localization of both alleles and by immunofluorescence assay was performed.Results: RT-PCR analysis revealed no significant levels of messenger RNA (mRNA LTA in healthy human retinas. Sequential IHC staining showed differences between healthy human and RD retinas. No differences in mRNA and protein expression levels and in subcellular localization between both alleles were found. Both alleles were located in the cytoplasm of COS-1 cells.Conclusion: Although results suggest lack of functionality, the differences found in IHC study and its strong association

  3. LA AUTONOMÍA DE LA PERSONA FRENTE AL DERECHO A LA VIDA NO INCLUYE EL DERECHO A SER MUERTO POR UN TERCERO: LA SOLICITUD DE ASISTENCIA AL SUICIDIO Y EL CASO DE DIANE PRETTY A AUTONOMIA DA PESSOA FRENTE AO DIREITO À VIDA NÃO INCLUI O DIREITO A SER MORTO POR UM TERCEIRO: A SOLICITAÇÃO AO SUICÍDIO ASSISTIDO E O CASO DE DIANE PRETTY A PERSON'S AUTONOMY VIS-À-VIS THE RIGHT TO LIFE DOES NOT INCLUDE THE RIGHT TO BE KILLED BY A THIRD PERSON: ASSISTANCE REQUEST TO COMMIT SUICIDE AND DIANE PRETTY'S CASE

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    Ángela Vivanco Martínez

    2002-01-01

    Full Text Available La autora, en la presente monografía, analiza las resoluciones pronunciadas por la House of Lords y por la Corte Europea de Derechos Humanos en el caso de Diane Pretty, ciudadana inglesa fallecida en mayo de 2002 quien, a causa de una enfermedad degenerativa e incurable, pretendió se reconociera inmunidad a su marido en caso de prestarle asistencia para suicidarse. Los fallos examinados rechazaron la solicitud de la recurrenteNa presente monografia a autora analisa as decisões emanadas pela Câmara do Lordes e Corte Européia de Direitos Humanos no caso Diane Pretty, cidadã inglesa falecida em maio de 2002 que em decorrência de enfermidade degenerativa incurável, pretendeu fosse reconhecida imunidade a seu marido para que a auxiliasse a suicidarse. As decisões recusaram a solicitação da recorrenteThe author of this monograph analyses the resolutions pronounced by the House of Lords and by the European Court of Human Rights in the case of Diane Pretty, an English citizen who died in may 2002. Because of a degenerative and incurable disease she pretended her husband be granted immunity if he helped her to commit suicide. The verdicts which were examined rejected her request

  4. Imaging an optogenetic pH sensor reveals that protons mediate lateral inhibition in the retina.

    Science.gov (United States)

    Wang, Tzu-Ming; Holzhausen, Lars C; Kramer, Richard H

    2014-02-01

    The reciprocal synapse between photoreceptors and horizontal cells underlies lateral inhibition and establishes the antagonistic center-surround receptive fields of retinal neurons to enhance visual contrast. Despite decades of study, the signal mediating the negative feedback from horizontal cells to cones has remained under debate because the small, invaginated synaptic cleft has precluded measurement. Using zebrafish retinas, we show that light elicits a change in synaptic proton concentration with the correct magnitude, kinetics and spatial dependence to account for lateral inhibition. Light, which hyperpolarizes horizontal cells, causes synaptic alkalinization, whereas activating an exogenously expressed ligand-gated Na(+) channel, which depolarizes horizontal cells, causes synaptic acidification. Whereas acidification was prevented by blocking a proton pump, re-alkalinization was prevented by blocking proton-permeant ion channels, suggesting that distinct mechanisms underlie proton efflux and influx. These findings reveal that protons mediate lateral inhibition in the retina, raising the possibility that protons are unrecognized retrograde messengers elsewhere in the nervous system.

  5. The utilization of glutamine by the retina: an autoradiographic and metabolic study

    International Nuclear Information System (INIS)

    Voaden, M.J.; Lake, N.; Marshall, J.; Morjaria, B.

    1978-01-01

    The cells able to accumulate exogenously applied [ 3 H] glutamine in rat, cat, frog, pigeon and guinea pig retinas have been located by autoradiography, and the fate of the labelled glutamine, as regards its incorporation into aspartic, glutamic and γ-amino-butyric acids, followed for 60 min. The results support the notion of glutamine as a precursor of transmitter amino acids in some neurones. In particular, it would appear to be a source of a relatively stable pool of GABA which may be located, with species variation, in amacrine or ganglion cells. In the pigeon retina glutamate pool incorporates and retains a major percentage of the label, and perikarya in the middle of the inner nuclear layer of the tissue are predominantly labelled. (author)

  6. [Expression of vimentin and GFAP and development of the retina in the trout].

    Science.gov (United States)

    De Guevara, R; Pairault, C; Pinganaud, G

    1994-08-01

    The glial cell development was studied during the edification of the retina and the optic tract, in a teleost, the rainbow trout. The intermediate filament proteins, vimentin and glial fibrillary acidic protein (GFAP) were visualized by an indirect immunohistochemical method. Results show that both vimentin and GFAP are early expressed in the developing retina and, particularly in the Müller cells, a coexpression of vimentin and GFAP is observed from embryonic to adult stages. The ganglion cell layer and the optic fiber layer both exhibit GFAP-positive structures. The deep staining for GFAP is also seen in the optic nerve and induces us to credit astrocyte-like cells with a leading role in the pattern formation of this tract.

  7. Electroretinography: A biopotential to assess the function/dysfunction of the retina

    Science.gov (United States)

    Quintana, Quinteros; Benedetto, M. L.; Maldonado, M. M.; de Payer E., A. C. Vera; Contin, M. A.

    2016-04-01

    The Electroretinography (ERG) is a noninvasive technique that allows the assessment of functional integrity of the retina. The ERG recordings are biopotencials acquired in the corneal surface as a response of retinal tissue against controlled light stimuli. In clinical ophthalmology ERG is not commonly used but nowadays, because of the high incidence of degenerative diseases of the retina (RD), its use should be increased. Like other biopotentials as electrocardiography (ECG), electroencephalogram (EEG) and electromyography (EMG), ERG is a low amplitude signal, in this case a few hundred of microvolts (µV), which must be fitted and processed. The ERG signals are affected in morphology in the presence of pathologies that affects the integrity of the different retinal cell groups, for example due to some RD. In advanced cases of RD recordings can be abolished in the time domain; and yet in them it is believed that there is relevant clinical information making the ERG a great potential diagnostic tool.

  8. Microscopic hyperspectral imaging studies of normal and diabetic retina of rats

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A microscopic hyperspectral imager was developed based on the microscopic technology and the spectral imaging technology. Some microscopic hyperspectral images of retina sections of the normal, the diabetic, and the treated rats were collected by the new imager. Single-band images and pseudo-color images of each group were obtained and the typical transmittance spectrums were ex-tracted. The results showed that the transmittance of outer nuclear layer cells of the diabetic group was generally higher than that of the normal. A small absorption peak appeared near the 180th band in the spectrum of the diabetic group and this peak weakened or disappeared in the spectrum of the treated group. Our findings indicate that the microscopic hyperspectral images include wealthy information of retina sections which is helpful for the ophthalmologist to reveal the pathogenesis of diabetic reti-nopathy and explore the therapeutic effect of drugs.

  9. Radicals excess in the retina: A model for light flashes in space

    International Nuclear Information System (INIS)

    Narici, L.; De Martino, A.; Brunetti, V.; Rinaldi, A.; Sannita, W.G.; Paci, M.

    2009-01-01

    The risk due to cosmic radiation is a major issue in planning future missions to the Moon or Mars and would be critical if inadequately addressed. Functional risks must also be considered. The perception of light flashes reported by astronauts in space, and ascribed mostly to the action of ionizing radiation in the eye (retina), is an evidence for radiation functional interaction. No detailed model of the ion/retina interaction is yet available. Here we present the first model for a generation mechanism compatible with light flashes in space, and the results of in vitro tests supporting it. The model can be a common end point for the interactions between ionizing radiation and visual system in space. It would also support the assessment of functional radiation risks in space.

  10. Automated pathologies detection in retina digital images based on complex continuous wavelet transform phase angles.

    Science.gov (United States)

    Lahmiri, Salim; Gargour, Christian S; Gabrea, Marcel

    2014-10-01

    An automated diagnosis system that uses complex continuous wavelet transform (CWT) to process retina digital images and support vector machines (SVMs) for classification purposes is presented. In particular, each retina image is transformed into two one-dimensional signals by concatenating image rows and columns separately. The mathematical norm of phase angles found in each one-dimensional signal at each level of CWT decomposition are relied on to characterise the texture of normal images against abnormal images affected by exudates, drusen and microaneurysms. The leave-one-out cross-validation method was adopted to conduct experiments and the results from the SVM show that the proposed approach gives better results than those obtained by other methods based on the correct classification rate, sensitivity and specificity.

  11. Uptake and release of [14C] GABA from rabbit retina synaptosomes

    International Nuclear Information System (INIS)

    Redburn, D.A.

    1977-01-01

    A partial separation of two synaptosomal fractions was achieved using modifications of conventional homogenization and centrifugation techniques. The two fractions contained morphologically distinct synaptosomal populations, receptor cell synaptosomes (large synaptosomes, P 1 ), and synaptosomes from the other cell types (smaller, conventional-sized synaptosomes, P 2 ). [ 14 C]GABA was bound and released from subcellular fractions from retina under conditions which support its role as a neurotransmitter in retina. On the other hand, [ 3 H]leucine, which is very likely a non-transmitter compound, was bound by retinal fractions but not released to the appropriate stimulation. [ 14 C]GABA binding and release sites were more prevalent in P 2 fractions. [ 14 C]GABA was bound by P 1 fractions containing photoreceptor synaptosomes; however, the K + stimulated release of [ 14 C]GABA appeared to be insensitive to external Ca 2+ . Possible mechanisms are discussed. (author)

  12. Distribution and protective function of pituitary adenylate cyclase-activating polypeptide (PACAP in the retina

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    Tomoya eNakamachi

    2012-11-01

    Full Text Available Pituitary adenylate cyclase-activating polypeptide (PACAP, which is found in 27- or 38-amino acid forms, belongs to the VIP/glucagon/secretin family. PACAP and its three receptor subtypes are expressed in neural tissues, with PACAP known to exert a protective effect against several types of neural damage. The retina is considered to be part of the central nervous system, and retinopathy is a common cause of profound and intractable loss of vision. This review will examine the expression and morphological distribution of PACAP and its receptors in the retina, and will summarize the current state of knowledge regarding the protective effect of PACAP against different kinds of retinal damage, such as that identified in association with diabetes, ultraviolet light, hypoxia, optic nerve transection, and toxins. This article will also address PACAP-mediated protective pathways involving retinal glial cells.

  13. Sonic hedgehog promotes stem-cell potential of Mueller glia in the mammalian retina

    International Nuclear Information System (INIS)

    Wan Jin; Zheng Hua; Xiao Honglei; She Zhenjue; Zhou Guomin

    2007-01-01

    Mueller glia have been demonstrated to display stem-cell properties after retinal damage. Here, we report this potential can be regulated by Sonic hedgehog (Shh) signaling. Shh can stimulate proliferation of Mueller glia through its receptor and target gene expressed on them, furthermore, Shh-treated Mueller glia are induced to dedifferentiate by expressing progenitor-specific markers, and then adopt cell fate of rod photoreceptor. Inhibition of signaling by cyclopamine inhibits proliferation and dedifferentiation. Intraocular injection of Shh promotes Mueller glia activation in the photoreceptor-damaged retina, Shh also enhances neurogenic potential by producing more rhodopsin-positive photoreceptors from Mueller glia-derived cells. Together, these results provide evidences that Mueller glia act as potential stem cells in mammalian retina, Shh may have therapeutic effects on these cells for promoting the regeneration of retinal neurons

  14. Sonic hedgehog promotes stem-cell potential of Mueller glia in the mammalian retina

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Wan; Hua, Zheng; Honglei, Xiao; Zhenjue, She [Department of Anatomy, Histology and Embryology, Shanghai Medical School, Fudan University, 200032 Shanghai (China); Zhou Guomin [Department of Anatomy, Histology and Embryology, Shanghai Medical School, Fudan University, 200032 Shanghai (China)], E-mail: gmzhou185@yahoo.com.cn

    2007-11-16

    Mueller glia have been demonstrated to display stem-cell properties after retinal damage. Here, we report this potential can be regulated by Sonic hedgehog (Shh) signaling. Shh can stimulate proliferation of Mueller glia through its receptor and target gene expressed on them, furthermore, Shh-treated Mueller glia are induced to dedifferentiate by expressing progenitor-specific markers, and then adopt cell fate of rod photoreceptor. Inhibition of signaling by cyclopamine inhibits proliferation and dedifferentiation. Intraocular injection of Shh promotes Mueller glia activation in the photoreceptor-damaged retina, Shh also enhances neurogenic potential by producing more rhodopsin-positive photoreceptors from Mueller glia-derived cells. Together, these results provide evidences that Mueller glia act as potential stem cells in mammalian retina, Shh may have therapeutic effects on these cells for promoting the regeneration of retinal neurons.

  15. An artificial retina processor for track reconstruction at the LHC crossing rate

    Science.gov (United States)

    Bedeschi, F.; Cenci, R.; Marino, P.; Morello, M. J.; Ninci, D.; Piucci, A.; Punzi, G.; Ristori, L.; Spinella, F.; Stracka, S.; Tonelli, D.; Walsh, J.

    2017-10-01

    The goal of the INFN-RETINA R&D project is to develop and implement a computational methodology that allows to reconstruct events with a large number (> 100) of charged-particle tracks in pixel and silicon strip detectors at 40 MHz, thus matching the requirements for processing LHC events at the full bunch-crossing frequency. Our approach relies on a parallel pattern-recognition algorithm, dubbed artificial retina, inspired by the early stages of image processing by the brain. In order to demonstrate that a track-processing system based on this algorithm is feasible, we built a sizable prototype of a tracking processor tuned to 3 000 patterns, based on already existing readout boards equipped with Altera Stratix III FPGAs. The detailed geometry and charged-particle activity of a large tracking detector currently in operation are used to assess its performances. We report on the test results with such a prototype.

  16. The area centralis in the chicken retina contains efferent target amacrine cells

    Science.gov (United States)

    Weller, Cynthia; Lindstrom, Sarah H.; De Grip, Willem J.; Wilson, Martin

    2012-01-01

    The retinas of birds receive a substantial efferent, or centrifugal, input from a midbrain nucleus. The function of this input is presently unclear but previous work in the pigeon has shown that efferent input is excluded from the area centralis, suggesting that the functions of the area centralis and the efferent system are incompatible. Using an antibody specific to rods, we have identified the area centralis in another species, the chicken, and mapped the distribution of the unique amacrine cells that are the postsynaptic partners of efferent fibers. Efferent target amacrine cells are found within the chicken area centralis and their density is continuous across the border of the area centralis. In contrast to the pigeon retina then, we conclude that the chicken area centralis receives efferent input. We suggest that the difference between the 2 species is attributable to the presence of a fovea within the area centralis of the pigeon and its absence from that of the chicken. PMID:19296862

  17. Utilization of glutamine by the retina: an autoradiographic and metabolic study

    Energy Technology Data Exchange (ETDEWEB)

    Voaden, M J; Lake, N; Marshall, J; Morjaria, B [Institute of Ophthalmology, London (UK). Dept. of Visual Science

    1978-10-01

    The cells able to accumulate exogenously applied (/sup 3/H) glutamine in rat, cat, frog, pigeon and guinea pig retinas have been located by autoradiography, and the fate of the labelled glutamine, as regards its incorporation into aspartic, glutamic and ..gamma..-amino-butyric acids, followed for 60 min. The results support the notion of glutamine as a precursor of transmitter amino acids in some neurones. In particular, it would appear to be a source of a relatively stable pool of GABA which may be located, with species variation, in amacrine or ganglion cells. In the pigeon retina glutamate pool incorporates and retains a major percentage of the label, and perikarya in the middle of the inner nuclear layer of the tissue are predominantly labelled.

  18. Unidirectional photoreceptor-to-Müller glia coupling and unique K+ channel expression in Caiman retina.

    Directory of Open Access Journals (Sweden)

    Astrid Zayas-Santiago

    Full Text Available Müller cells, the principal glial cells of the vertebrate retina, are fundamental for the maintenance and function of neuronal cells. In most vertebrates, including humans, Müller cells abundantly express Kir4.1 inwardly rectifying potassium channels responsible for hyperpolarized membrane potential and for various vital functions such as potassium buffering and glutamate clearance; inter-species differences in Kir4.1 expression were, however, observed. Localization and function of potassium channels in Müller cells from the retina of crocodiles remain, hitherto, unknown.We studied retinae of the Spectacled caiman (Caiman crocodilus fuscus, endowed with both diurnal and nocturnal vision, by (i immunohistochemistry, (ii whole-cell voltage-clamp, and (iii fluorescent dye tracing to investigate K+ channel distribution and glia-to-neuron communications.Immunohistochemistry revealed that caiman Müller cells, similarly to other vertebrates, express vimentin, GFAP, S100β, and glutamine synthetase. In contrast, Kir4.1 channel protein was not found in Müller cells but was localized in photoreceptor cells. Instead, 2P-domain TASK-1 channels were expressed in Müller cells. Electrophysiological properties of enzymatically dissociated Müller cells without photoreceptors and isolated Müller cells with adhering photoreceptors were significantly different. This suggests ion coupling between Müller cells and photoreceptors in the caiman retina. Sulforhodamine-B injected into cones permeated to adhering Müller cells thus revealing a uni-directional dye coupling.Our data indicate that caiman Müller glial cells are unique among vertebrates studied so far by predominantly expressing TASK-1 rather than Kir4.1 K+ channels and by bi-directional ion and uni-directional dye coupling to photoreceptor cells. This coupling may play an important role in specific glia-neuron signaling pathways and in a new type of K+ buffering.

  19. Neuroprotective effect of bilberry extract in a murine model of photo-stressed retina.

    Directory of Open Access Journals (Sweden)

    Hideto Osada

    Full Text Available Excessive exposure to light promotes degenerative and blinding retinal diseases such as age-related macular degeneration and retinitis pigmentosa. However, the underlying mechanisms of photo-induced retinal degeneration are not fully understood, and a generalizable preventive intervention has not been proposed. Bilberry extract is an antioxidant-rich supplement that ameliorates ocular symptoms. However, its effects on photo-stressed retinas have not been clarified. In this study, we examined the neuroprotective effects of bilberry extract against photo-stress in murine retinas. Light-induced visual function impairment recorded by scotopic and phototopic electroretinograms showing respective rod and cone photoreceptor function was attenuated by oral administration of bilberry extract through a stomach tube in Balb/c mice (750 mg/kg body weight. Bilberry extract also suppressed photo-induced apoptosis in the photoreceptor cell layer and shortening of the outer segments of rod and cone photoreceptors. Levels of photo-induced reactive oxygen species (ROS, oxidative and endoplasmic reticulum (ER stress markers, as measured by real-time reverse transcriptase polymerase chain reaction, were reduced by bilberry extract treatment. Reduction of ROS by N-acetyl-L-cysteine, a well-known antioxidant also suppressed ER stress. Immunohistochemical analysis of activating transcription factor 4 expression showed the presence of ER stress in the retina, and at least in part, in Müller glial cells. The photo-induced disruption of tight junctions in the retinal pigment epithelium was also attenuated by bilberry extract, repressing an oxidative stress marker, although ER stress markers were not repressed. Our results suggest that bilberry extract attenuates photo-induced apoptosis and visual dysfunction most likely, and at least in part, through ROS reduction, and subsequent ER stress attenuation in the retina. This study can help understand the mechanisms of photo

  20. Avian cone photoreceptors tile the retina as five independent, self-organizing mosaics.

    Directory of Open Access Journals (Sweden)

    Yoseph A Kram

    2010-02-01

    Full Text Available The avian retina possesses one of the most sophisticated cone photoreceptor systems among vertebrates. Birds have five types of cones including four single cones, which support tetrachromatic color vision and a double cone, which is thought to mediate achromatic motion perception. Despite this richness, very little is known about the spatial organization of avian cones and its adaptive significance. Here we show that the five cone types of the chicken independently tile the retina as highly ordered mosaics with a characteristic spacing between cones of the same type. Measures of topological order indicate that double cones are more highly ordered than single cones, possibly reflecting their posited role in motion detection. Although cones show spacing interactions that are cell type-specific, all cone types use the same density-dependent yardstick to measure intercone distance. We propose a simple developmental model that can account for these observations. We also show that a single parameter, the global regularity index, defines the regularity of all five cone mosaics. Lastly, we demonstrate similar cone distributions in three additional avian species, suggesting that these patterning principles are universal among birds. Since regular photoreceptor spacing is critical for uniform sampling of visual space, the cone mosaics of the avian retina represent an elegant example of the emergence of adaptive global patterning secondary to simple local interactions between individual photoreceptors. Our results indicate that the evolutionary pressures that gave rise to the avian retina's various adaptations for enhanced color discrimination also acted to fine-tune its spatial sampling of color and luminance.

  1. Targeting iodothyronine deiodinases locally in the retina is a therapeutic strategy for retinal degeneration.

    Science.gov (United States)

    Yang, Fan; Ma, Hongwei; Belcher, Joshua; Butler, Michael R; Redmond, T Michael; Boye, Sanford L; Hauswirth, William W; Ding, Xi-Qin

    2016-12-01

    Recent studies have implicated thyroid hormone (TH) signaling in cone photoreceptor viability. Using mouse models of retinal degeneration, we found that antithyroid treatment preserves cones. This work investigates the significance of targeting intracellular TH components locally in the retina. The cellular TH level is mainly regulated by deiodinase iodothyronine (DIO)-2 and -3. DIO2 converts thyroxine (T4) to triiodothyronine (T3), which binds to the TH receptor, whereas DIO3 degrades T3 and T4. We examined cone survival after overexpression of DIO3 and inhibition of DIO2 and demonstrated the benefits of these manipulations. Subretinal delivery of AAV5-IRBP/GNAT2-DIO3, which directs expression of human DIO3 specifically in cones, increased cone density by 30-40% in a Rpe65 -/- mouse model of Lebers congenital amaurosis (LCA) and in a Cpfl1 mouse with Pde6c defect model of achromatopsia, compared with their respective untreated controls. Intravitreal and topical delivery of the DIO2 inhibitor iopanoic acid also significantly improved cone survival in the LCA model mice. Moreover, the expression levels of DIO2 and Slc16a2 were significantly higher in the diseased retinas, suggesting locally elevated TH signaling. We show that targeting DIOs protects cones, and intracellular inhibition of TH components locally in the retina may represent a novel strategy for retinal degeneration management.-Yang, F., Ma, H., Belcher, J., Butler, M. R., Redmond, T. M., Boye, S. L., Hauswirth, W. W., Ding, X.-Q. Targeting iodothyronine deiodinases locally in the retina is a therapeutic strategy for retinal degeneration. © FASEB.

  2. Potassium-stimulated release of radiolabelled taurine and glycine from the isolated rat retina

    Energy Technology Data Exchange (ETDEWEB)

    Smith, L.F.; Pycock, C.J.

    1982-09-01

    The release of preloaded (/sup 3/H)glycine and (/sup 3/H)taurine in response to a depolarising stimulus (12.5-50 mM KCl) has been studied in the superfused rat retina. High external potassium concentration immediately increased the spontaneous efflux of (/sup 3/H)glycine, the effect of 50 mM K+ apparently being abolished by omitting calcium from the superfusing medium. In contrast, although high potassium concentrations increased the spontaneous efflux of (/sup 3/H)taurine from the superfused rat retina, this release was not evident until the depolarising stimulus was removed from the superfusing medium. The magnitude of this late release of (/sup 3/H)taurine was dependent on external K+ concentrations, and appeared immediately after cessation of the stimulus irrespective of whether it was applied for 4, 8, or 12 min. Potassium (50 mM)-induced release of taurine appeared partially calcium-dependent, being significantly reduced (p less than 0.01) but not abolished by replacing calcium with 1 mM EDTA in the superfusate. High-affinity uptake systems for both (/sup 3/H)glycine and (/sup 3/H)taurine were demonstrated in the rat retina in vitro (Km values, 1.67 microM and 2.97 microM; Vmax values, 19.3 and 23.1 nmol/g wet weight tissue/h, respectively). The results are discussed with respect to the possible neurotransmitter roles of both amino acids in the rat retina.

  3. Lipid nanoparticles as drug/gene delivery systems to the retina.

    Science.gov (United States)

    del Pozo-Rodríguez, Ana; Delgado, Diego; Gascón, Alicia R; Solinís, Maria Ángeles

    2013-03-01

    This review highlights the application of lipid nanoparticles (Solid Lipid Nanoparticles, Nanostructured Lipid Carriers, or Lipid Drug Conjugates) as effective drug/gene delivery systems for retinal diseases. Most drug products for ocular disease treatment are marketed as eye drop formulations but, due to ocular barriers, the drug concentration in the retina hardly ever turns out to be effective. Up to this date, several delivery systems have been designed to deliver drugs to the retina. Drug delivery strategies may be classified into 3 groups: noninvasive techniques, implants, and colloidal carriers. The best known systems for drug delivery to the posterior eye are intravitreal implants; in fact, some of them are being clinically used. However, their long-term accumulation might impact the patient's vision. On the contrary, colloidal drug delivery systems (microparticles, liposomes, or nanoparticles) can be easily administered in a liquid form. Nanoparticular systems diffuse rapidly and are better internalized in ocular tissues than microparticles. In comparison with liposomes, nanoparticles have a higher loading capacity and are more stable in biological fluids and during storage. In addition, their capacity to adhere to the ocular surface and interact with the endothelium makes these drug delivery systems interesting as new therapeutic tools in ophthalmology. Within the group of nanoparticles, those composed of lipids (Solid Lipid Nanoparticles, Nanostructred Lipid Carriers, and Lipid Drug Conjugates) are more biocompatible, easy to produce at large scale, and they may be autoclaved or sterilized. The present review summarizes scientific results that evidence the potential application of lipid nanoparticles as drug delivery systems for the retina and also as nonviral vectors in gene therapy of retina disorders, although much more effort is still needed before these lipidic systems could be available in the market.

  4. Optimal wavelet transform for the detection of microaneurysms in retina photographs

    OpenAIRE

    Quellec, Gwénolé; Lamard, Mathieu; Josselin, Pierre Marie; Cazuguel, Guy; Cochener, Béatrice; Roux, Christian

    2008-01-01

    11 pages; International audience; In this paper, we propose an automatic method to detect microaneurysms in retina photographs. Microaneurysms are the most frequent and usually the first lesions to appear as a consequence of diabetic retinopathy. So, their detection is necessary for both screening the pathology and follow up (progression measurement). Automating this task, which is currently performed manually, would bring more objectivity and reproducibility. We propose to detect them by loc...

  5. PGC-1α determines light damage susceptibility of the murine retina.

    Directory of Open Access Journals (Sweden)

    Anna Egger

    Full Text Available The peroxisome proliferator-activated receptor γ coactivator 1 (PGC-1 proteins are key regulators of cellular bioenergetics and are accordingly expressed in tissues with a high energetic demand. For example, PGC-1α and PGC-1β control organ function of brown adipose tissue, heart, brain, liver and skeletal muscle. Surprisingly, despite their prominent role in the control of mitochondrial biogenesis and oxidative metabolism, expression and function of the PGC-1 coactivators in the retina, an organ with one of the highest energy demands per tissue weight, are completely unknown. Moreover, the molecular mechanisms that coordinate energy production with repair processes in the damaged retina remain enigmatic. In the present study, we thus investigated the expression and function of the PGC-1 coactivators in the healthy and the damaged retina. We show that PGC-1α and PGC-1β are found at high levels in different structures of the mouse retina, most prominently in the photoreceptors. Furthermore, PGC-1α knockout mice suffer from a striking deterioration in retinal morphology and function upon detrimental light exposure. Gene expression studies revealed dysregulation of all major pathways involved in retinal damage and apoptosis, repair and renewal in the PGC-1α knockouts. The light-induced increase in apoptosis in vivo in the absence of PGC-1α was substantiated in vitro, where overexpression of PGC-1α evoked strong anti-apoptotic effects. Finally, we found that retinal levels of PGC-1 expression are reduced in different mouse models for retinitis pigmentosa. We demonstrate that PGC-1α is a central coordinator of energy production and, importantly, all of the major processes involved in retinal damage and subsequent repair. Together with the observed dysregulation of PGC-1α and PGC-1β in retinitis pigmentosa mouse models, these findings thus imply that PGC-1α might be an attractive target for therapeutic approaches aimed at retinal

  6. In vivo two-photon imaging of retina in rabbits and rats.

    Science.gov (United States)

    Jayabalan, Gopal Swamy; Wu, Yi-Kai; Bille, Josef F; Kim, Samuel; Mao, Xiao Wen; Gimbel, Howard V; Rauser, Michael E; Fan, Joseph T

    2018-01-01

    The purpose of this study was to evaluate the retina using near-infrared (NIR) two-photon scanning laser ophthalmoscopy. New Zealand white rabbits, albino rats, and brown Norway rats were used in this study. An autofluorescence image of the retina, including the retinal cells and its associated vasculatures was obtained by a real-time scan using the ophthalmoscope. Furthermore, the retinal vessels, nerve fiber layers and the non-pigmented retina were recorded with two-photon fluorescein angiography (FA); and the choroidal vasculatures were recorded using two-photon indocyanine green angiography (ICGA). Two-photon ICGA was achieved by exciting a second singlet state at ∼398 nm. Simultaneous two-photon FA and two-photon ICGA were performed to characterize the retinal and choroidal vessels with a single injection. The minimum laser power threshold required to elicit two-photon fluorescence was determined. The two-photon ophthalmoscope could serve as a promising tool to detect and monitor the disease progression in animal models. Moreover, these high-resolution images of retinal and choroidal vessels can be acquired in a real-time scan with a single light source, requiring no additional filters for FA or ICGA. The combination of FA and ICGA using the two-photon ophthalmoscope will help researchers to characterize the retinal diseases in animal models, and also to classify the types (classic, occult or mixed) of choroidal neovascularization (CNV) in macular degeneration. Furthermore, the prototype can be adapted to image the retina of rodents and rabbits. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Descolamento de retina seroso em paraganglioma: relato de caso Serous retinal detachment in paraganglioma: case report

    Directory of Open Access Journals (Sweden)

    Oscar Villas Boas

    2008-02-01

    Full Text Available Os autores descrevem um caso de uma paciente gestante com hipertensão arterial resistente ao tratamento e descolamento seroso bilateral de retina. Confirmou-se, pelo exame anátomo-patológico, ser um paraganglioma.The authors describe a case of a pregnant patient with arterial hypertension that resists to the treatment and retinal bilateral serous detachment. It was confirmed to be a paraganglioma by anatomicopathological examination.

  8. Pushing the limits of photoreception in twilight conditions: The rod-like cone retina of the deep-sea pearlsides

    KAUST Repository

    Busserolles, Fanny de; Cortesi, Fabio; Helvik, Jon Vidar; Davies, Wayne I. L.; Templin, Rachel M.; Sullivan, Robert K. P.; Michell, Craig T.; Mountford, Jessica K.; Collin, Shaun P.; Irigoien, Xabier; Kaartvedt, Stein; Marshall, Justin

    2017-01-01

    retina does not have rod photoreceptors only; instead, it is composed almost exclusively of transmuted cone photoreceptors. These transmuted cells combine the morphological characteristics of a rod photoreceptor with a cone opsin and a cone

  9. The noncoding RNA taurine upregulated gene 1 is required for differentiation of the murine retina.

    Science.gov (United States)

    Young, T L; Matsuda, T; Cepko, C L

    2005-03-29

    With the advent of genome-wide analyses, it is becoming evident that a large number of noncoding RNAs (ncRNAs) are expressed in vertebrates. However, of the thousands of ncRNAs identified, the functions of relatively few have been established. In a screen for genes upregulated by taurine in developing retinal cells, we identified a gene that appears to be a ncRNA. Taurine Upregulated Gene 1 (TUG1) is a spliced, polyadenylated RNA that does not encode any open reading frame greater than 82 amino acids in its full-length, 6.7 kilobase (kb) RNA sequence. Analyses of Northern blots and in situ hybridization revealed that TUG1 is expressed in the developing retina and brain, as well as in adult tissues. In the newborn retina, knockdown of TUG1 with RNA interference (RNAi) resulted in malformed or nonexistent outer segments of transfected photoreceptors. Immunofluorescent staining and microarray analyses suggested that this loss of proper photoreceptor differentiation is a result of the disregulation of photoreceptor gene expression. A function for a newly identified ncRNA, TUG1, has been established. TUG1 is necessary for the proper formation of photoreceptors in the developing rodent retina.

  10. Two-photon excited autofluorescence imaging of freshly isolated frog retinas.

    Science.gov (United States)

    Lu, Rong-Wen; Li, Yi-Chao; Ye, Tong; Strang, Christianne; Keyser, Kent; Curcio, Christine A; Yao, Xin-Cheng

    2011-06-01

    The purpose of this study was to investigate cellular sources of autofluorescence signals in freshly isolated frog (Rana pipiens) retinas. Equipped with an ultrafast laser, a laser scanning two-photon excitation fluorescence microscope was employed for sub-cellular resolution examination of both sliced and flat-mounted retinas. Two-photon imaging of retinal slices revealed autofluorescence signals over multiple functional layers, including the photoreceptor layer (PRL), outer nuclear layer (ONL), outer plexiform layer (OPL), inner nuclear layer (INL), inner plexiform layer (IPL), and ganglion cell layer (GCL). Using flat-mounted retinas, depth-resolved imaging of individual retinal layers further confirmed multiple sources of autofluorescence signals. Cellular structures were clearly observed at the PRL, ONL, INL, and GCL. At the PRL, the autofluorescence was dominantly recorded from the intracellular compartment of the photoreceptors; while mixed intracellular and extracellular autofluorescence signals were observed at the ONL, INL, and GCL. High resolution autofluorescence imaging clearly revealed mosaic organization of rod and cone photoreceptors; and sub-cellular bright autofluorescence spots, which might relate to connecting cilium, was observed in the cone photoreceptors only. Moreover, single-cone and double-cone outer segments could be directly differentiated.

  11. Coherent anti-stokes Raman scattering (CARS) microscopy: a novel technique for imaging the retina.

    Science.gov (United States)

    Masihzadeh, Omid; Ammar, David A; Kahook, Malik Y; Lei, Tim C

    2013-05-01

    To image the cellular and noncellular structures of the retina in an intact mouse eye without the application of exogenous fluorescent labels using noninvasive, nondestructive techniques. Freshly enucleated mouse eyes were imaged using two nonlinear optical techniques: coherent anti-Stokes Raman scattering (CARS) and two-photon autofluorescence (TPAF). Cross sectional transverse sections and sequential flat (en face) sagittal sections were collected from a region of sclera approximately midway between the limbus and optic nerve. Imaging proceeded from the surface of the sclera to a depth of ∼60 μm. The fluorescent signal from collagen fibers within the sclera was evident in the TPAF channel; the scleral collagen fibers showed no organization and appeared randomly packed. The sclera contained regions lacking TPAF and CARS fluorescence of ∼3 to 15 μm in diameter that could represent small vessels or scleral fibroblasts. Intense punctate CARS signals from the retinal pigment epithelial layer were of a size and shape of retinyl storage esters. Rod outer segments could be identified by the CARS signal from their lipid-rich plasma membranes. CARS microscopy can be used to image the outer regions of the mammalian retina without the use of a fluorescent dye or exogenously expressed recombinant protein. With technical advancements, CARS/TPAF may represent a new avenue for noninvasively imaging the retina and might complement modalities currently used in clinical practice.

  12. A Novel Nanoparticle Mediated Selective Inner Retinal Photocoagulation for Diseases of the Inner Retina.

    Science.gov (United States)

    Singh, Rupesh; Rajaraman, Srinivas; Balasubramanian, Madhusudhanan

    2017-10-01

    A novel nanoparticle mediated methodology for laser photocoagulation of the inner retina to achieve tissue selective treatment is presented. Transport of 527, 577, and 810 nm laser, heat deposition, and eventual thermal damage in vitreous, retina, RPE, choroid, and sclera were modeled using Bouguer-Beer-Lambert law of absorption and solved numerically using the finite volume method. Nanoparticles were designed using Mie theory of scattering. Performance of the new photocoagulation strategy using gold nanospheres and gold-silica nanoshells was compared with that of conventional methods without nanoparticles. For experimental validation, vitreous cavity of ex vivo porcine eyes was infused with gold nanospheres. After ~6 h of nanoparticle diffusion, the porcine retina was irradiated with a green laser and imaged simultaneously using a spectral domain optical coherence tomography (Spectralis SD-OCT, Heidelberg Engineering). Our computational model predicted a significant spatial shift in the peak temperature from RPE to the inner retinal region when infused with nanoparticles. Arrhenius thermal damage in the mid-retinal location was achieved in ~14 ms for 527 nm laser thereby reducing the irradiation duration by ~30 ms compared with the treatment without nanoparticles. In ex vivo porcine eyes infused with gold nanospheres, SD-OCT retinal images revealed a lower thermal damage and expansion at RPE due to laser photocoagulation. Nanoparticle infused laser photocoagulation strategy provided a selective inner retinal thermal damage with significant decrease in laser power and laser exposure time. The proposed treatment strategy shows possibilities for an efficient and highly selective inner retinal laser treatment.

  13. Synaptic Remodeling Generates Synchronous Oscillations in the Degenerated Outer Mouse Retina

    Directory of Open Access Journals (Sweden)

    Wadood eHaq

    2014-09-01

    Full Text Available During neuronal degenerative diseases, neuronal microcircuits undergo severe structural alterations, leading to remodeling of synaptic connectivity. The functional consequences of such remodeling are mostly unknown. For instance, in mutant rd1 mouse retina, a common model for Retinitis Pigmentosa, rod bipolar cells (RBCs establish contacts with remnant cone photoreceptors (cones as a consequence of rod photoreceptor cell death and the resulting lack of presynaptic input. To assess the functional connectivity in the remodeled, light-insensitive outer rd1 retina, we recorded spontaneous population activity in retinal wholemounts using Ca2+ imaging and identified the participating cell types. Focusing on cones, RBCs and horizontal cells (HCs, we found that these cell types display spontaneous oscillatory activity and form synchronously active clusters. Overall activity was modulated by GABAergic inhibition from HCs. Many of the activity clusters comprised both cones and RBCs. Opposite to what is expected from the intact (wild-type cone-ON bipolar cell pathway, cone and RBC activity was positively correlated and, at least partially, mediated by glutamate transporters expressed on RBCs. Deletion of gap junctional coupling between cones reduced the number of clusters, indicating that electrical cone coupling plays a crucial role for generating the observed synchronized oscillations. In conclusion, degeneration-induced synaptic remodeling of the rd1 retina results in a complex self-sustained outer retinal oscillatory network, that complements (and potentially modulates the recently described inner retinal oscillatory network consisting of amacrine, bipolar and ganglion cells.

  14. MEMS scanner mirror based system for retina scanning and in eye projection

    Science.gov (United States)

    Woittennek, Franziska; Knobbe, Jens; Pügner, Tino; Dallmann, Hans-Georg; Schelinski, Uwe; Grüger, Heinrich

    2015-02-01

    Many applications could benefit from miniaturized systems to scan blood vessels behind the retina in the human eye, so called "retina scanning". This reaches from access control to sophisticated security applications and medical devices. High volume systems for consumer applications require low cost and a user friendly operation. For example this includes no need for removal of glasses and self-adjustment, in turn guidance of focus and point of attraction by simultaneous projection for the user. A new system has been designed based on the well-known resonantly driven 2-d scanner mirror of Fraunhofer IPMS. A combined NIR and VIS laser system illuminates the eye through an eye piece designed for an operating distance allowing the use of glasses and granting sufficient field of view. This usability feature was considered to be more important than highest miniaturization. The modulated VIS laser facilitates the projection of an image directly onto the retina. The backscattered light from the continuous NIR laser contains the information of the blood vessels and is detected by a highly sensitive photo diode. A demonstrational setup has been realized including readout and driving electronics. The laser power was adjusted to an eye-secure level. Additional security features were integrated. Test measurements revealed promising results. In a first demonstration application the detection of biometric pattern of the blood vessels was evaluated for issues authentication in.

  15. Developmentally Regulated Production of meso-Zeaxanthin in Chicken Retinal Pigment Epithelium/Choroid and Retina.

    Science.gov (United States)

    Gorusupudi, Aruna; Shyam, Rajalekshmy; Li, Binxing; Vachali, Preejith; Subhani, Yumna K; Nelson, Kelly; Bernstein, Paul S

    2016-04-01

    meso-Zeaxanthin is a carotenoid that is rarely encountered in nature outside of the vertebrate eye. It is not a constituent of a normal human diet, yet this carotenoid comprises one-third of the primate macular pigment. In the current study, we undertook a systematic approach to biochemically characterize the production of meso-zeaxanthin in the vertebrate eye. Fertilized White Leghorn chicken eggs were analyzed for the presence of carotenoids during development. Yolk, liver, brain, serum, retina, and RPE/choroid were isolated, and carotenoids were extracted. The samples were analyzed on C-30 or chiral HPLC columns to determine the carotenoid composition. Lutein and zeaxanthin were found in all studied nonocular tissues, but no meso-zeaxanthin was ever detected. Among the ocular tissues, the presence of meso-zeaxanthin was consistently observed starting at embryonic day 17 (E17) in the RPE/choroid, several days before its consistent detection in the retina. If RPE/choroid of an embryo was devoid of meso-zeaxanthin, the corresponding retina was always negative as well. This is the first report of developmentally regulated synthesis of meso-zeaxanthin in a vertebrate system. Our observations suggest that the RPE/choroid is the primary site of meso-zeaxanthin synthesis. Identification of meso-zeaxanthin isomerase enzyme in the developing chicken embryo will facilitate our ability to determine the biochemical mechanisms responsible for production of this unique carotenoid in other higher vertebrates, such as humans.

  16. Tlx, an orphan nuclear receptor, regulates cell numbers and astrocyte development in the developing retina.

    Science.gov (United States)

    Miyawaki, Takaya; Uemura, Akiyoshi; Dezawa, Mari; Yu, Ruth T; Ide, Chizuka; Nishikawa, Shinichi; Honda, Yoshihito; Tanabe, Yasuto; Tanabe, Teruyo

    2004-09-15

    Tlx belongs to a class of orphan nuclear receptors that underlies many aspects of neural development in the CNS. However, the fundamental roles played by Tlx in the control of eye developmental programs remain elusive. By using Tlx knock-out (KO) mice, we show here that Tlx is expressed by retinal progenitor cells in the neuroblastic layer during the period of retinal layer formation, and it is critical for controlling the generation of appropriate numbers of retinal progenies through the activities of cell cycle-related molecules, cyclin D1 and p27Kip1. Tlx expression is restricted to Müller cells in the mature retina and appears to control their proper development. Furthermore, we show that Tlx is expressed by immature astrocytes that migrate from the optic nerve onto the inner surface of the retina and is required for their generation and maturation, as assessed by honeycomb network formation and expression of R-cadherin, a critical component for vasculogenesis. The impaired astrocyte network formation on the inner retinal surface is accompanied by the loss of vasculogenesis in Tlx KO retinas. Our studies thus indicate that Tlx underlies a fundamental developmental program of retinal organization and controls the generation of the proper numbers of retinal progenies and development of glial cells during the protracted period of retinogenesis.

  17. Design of a MEMS-based retina scanning system for biometric authentication

    Science.gov (United States)

    Woittennek, Franziska; Knobbe, Jens; Pügner, Tino; Schelinski, Uwe; Grüger, Heinrich

    2014-05-01

    There is an increasing need for reliable authentication for a number of applications such as e commerce. Common authentication methods based on ownership (ID card) or knowledge factors (password, PIN) are often prone to manipulations and may therefore be not safe enough. Various inherence factor based methods like fingerprint, retinal pattern or voice identifications are considered more secure. Retina scanning in particular offers both low false rejection rate (FRR) and low false acceptance rate (FAR) with about one in a million. Images of the retina with its characteristic pattern of blood vessels can be made with either a fundus camera or laser scanning methods. The present work describes the optical design of a new compact retina laser scanner which is based on MEMS (Micro Electric Mechanical System) technology. The use of a dual axis micro scanning mirror for laser beam deflection enables a more compact and robust design compared to classical systems. The scanner exhibits a full field of view of 10° which corresponds to an area of 4 mm2 on the retinal surface surrounding the optical disc. The system works in the near infrared and is designed for use under ambient light conditions, which implies a pupil diameter of 1.5 mm. Furthermore it features a long eye relief of 30 mm so that it can be conveniently used by persons wearing glasses. The optical design requirements and the optical performance are discussed in terms of spot diagrams and ray fan plots.

  18. Spontaneous oscillatory rhythms in the degenerating mouse retina modulate retinal ganglion cell responses to electrical stimulation

    Directory of Open Access Journals (Sweden)

    Yong Sook eGoo

    2016-01-01

    Full Text Available Characterization of the electrical activity of the retina in the animal models of retinal degeneration has been carried out in part to understand the progression of retinal degenerative diseases like age-related macular degeneration (AMD and retinitis pigmentosa (RP, but also to determine optimum stimulus paradigms for use with retinal prosthetic devices. The models most studied in this regard have been the two lines of mice deficient in the β-subunit of phosphodiesterase (rd1 and rd10 mice, where the degenerating retinas exhibit characteristic spontaneous hyperactivity and oscillatory local field potentials (LFPs. Additionally, there is a robust ~10 Hz rhythmic burst of retinal ganglion cell (RGC spikes on the trough of the oscillatory LFP. In rd1 mice, the rhythmic burst of RGC spikes is always phase-locked with the oscillatory LFP and this phase-locking property is preserved regardless of postnatal ages. However, in rd10 mice, the frequency of the oscillatory rhythm changes according to postnatal age, suggesting that this rhythm might be a marker of the stage of degeneration. Furthermore when a biphasic current stimulus is applied to rd10 mice degenerate retina, distinct RGC response patterns that correlate with the stage of degeneration emerge. This review also considers the significance of these response properties.

  19. Automatic and manual segmentation of healthy retinas using high-definition optical coherence tomography.

    Science.gov (United States)

    Golbaz, Isabelle; Ahlers, Christian; Goesseringer, Nina; Stock, Geraldine; Geitzenauer, Wolfgang; Prünte, Christian; Schmidt-Erfurth, Ursula Margarethe

    2011-03-01

    This study compared automatic- and manual segmentation modalities in the retina of healthy eyes using high-definition optical coherence tomography (HD-OCT). Twenty retinas in 20 healthy individuals were examined using an HD-OCT system (Carl Zeiss Meditec, Inc.). Three-dimensional imaging was performed with an axial resolution of 6 μm at a maximum scanning speed of 25,000 A-scans/second. Volumes of 6 × 6 × 2 mm were scanned. Scans were analysed using a matlab-based algorithm and a manual segmentation software system (3D-Doctor). The volume values calculated by the two methods were compared. Statistical analysis revealed a high correlation between automatic and manual modes of segmentation. The automatic mode of measuring retinal volume and the corresponding three-dimensional images provided similar results to the manual segmentation procedure. Both methods were able to visualize retinal and subretinal features accurately. This study compared two methods of assessing retinal volume using HD-OCT scans in healthy retinas. Both methods were able to provide realistic volumetric data when applied to raster scan sets. Manual segmentation methods represent an adequate tool with which to control automated processes and to identify clinically relevant structures, whereas automatic procedures will be needed to obtain data in larger patient populations. © 2009 The Authors. Journal compilation © 2009 Acta Ophthalmol.

  20. Taurine biosynthesis in frog retina: effects of light and dark adaptations

    International Nuclear Information System (INIS)

    Nishimura, C.; Ida, S.; Kuriyama, K.

    1983-01-01

    The retinal uptake and metabolism of cysteine, a precursor for taurine biosynthesis, were analysed using the bull frog. The [ 14 C] cysteine uptake into isolated retina had some specific properties: It was rather temperature independent, required Na ions, was inhibited by ouabain but not by dinitrophenol, and exhibited saturation kinetics composed of two components. When retinal homogenate was incubated with 12-30 microM of L-[U- 14 C]cysteine, the accumulation of labeled alanine, cysteine sulfinic acid (CSA), cysteic acid (CA), hypotaurine, and taurine was detected. The metabolic conversions of [ 14 C] cysteine to labeled alanine, hypotaurine, and taurine were linear over 90 minutes. Prolonged light adaptation (3 weeks) induced a significant reduction in the formation of labeled CA, CSA, hypotaurine, and taurine from [ 14 C] cysteine. On the other hand, it was found that in dark-adapted retinae, the formation of labeled taurine from [ 14 C] cysteine increased significantly in spite of the reduction in the formation of labeled CA. These results indicate that biosynthetic pathways exist for taurine from cysteine in frog retina, and that these metabolic pathways are involved in the regulation of retinal taurine content under continuous visual adaptation

  1. STRUCTURAL AND FUNCTIONAL CHARACTERIZATION OF BENIGN FLECK RETINA USING MULTIMODAL IMAGING.

    Science.gov (United States)

    Neriyanuri, Srividya; Rao, Chetan; Raman, Rajiv

    2017-01-01

    To report structural and functional features in a case series of benign fleck retina using multimodal imaging. Four cases with benign fleck retina underwent complete ophthalmic examination that included detailed history, visual acuity, and refractive error testing, FM-100 hue test, dilated fundus evaluation, full field electroretinogram, fundus photography with autofluorescence, fundus fluorescein angiography, and swept-source optical coherence tomography. Age group of the cases ranged from 19 years to 35 years (3 males and 1 female). Parental consanguinity was reported in two cases. All of them were visually asymptomatic with best-corrected visual acuity of 20/20 (moderate astigmatism) in both the eyes. Low color discrimination was seen in two cases. Fundus photography showed pisciform flecks which were compactly placed on posterior pole and were discrete, diverging towards periphery. Lesions were seen as smaller dots within 1500 microns from fovea and were hyperfluorescent on autofluorescence. Palisading retinal pigment epithelium defects were seen in posterior pole on fundus fluorescein angiography imaging; irregular hyper fluorescence was also noted. One case had reduced cone responses on full field electroretinogram; the other three cases had normal electroretinogram. On optical coherence tomography, level of lesions varied from retinal pigment epithelium, inner segment to outer segment extending till external limiting membrane. Functional and structural deficits in benign fleck retina were picked up using multimodal imaging.

  2. Vision drives correlated activity without patterned spontaneous activity in developing Xenopus retina.

    Science.gov (United States)

    Demas, James A; Payne, Hannah; Cline, Hollis T

    2012-04-01

    Developing amphibians need vision to avoid predators and locate food before visual system circuits fully mature. Xenopus tadpoles can respond to visual stimuli as soon as retinal ganglion cells (RGCs) innervate the brain, however, in mammals, chicks and turtles, RGCs reach their central targets many days, or even weeks, before their retinas are capable of vision. In the absence of vision, activity-dependent refinement in these amniote species is mediated by waves of spontaneous activity that periodically spread across the retina, correlating the firing of action potentials in neighboring RGCs. Theory suggests that retinorecipient neurons in the brain use patterned RGC activity to sharpen the retinotopy first established by genetic cues. We find that in both wild type and albino Xenopus tadpoles, RGCs are spontaneously active at all stages of tadpole development studied, but their population activity never coalesces into waves. Even at the earliest stages recorded, visual stimulation dominates over spontaneous activity and can generate patterns of RGC activity similar to the locally correlated spontaneous activity observed in amniotes. In addition, we show that blocking AMPA and NMDA type glutamate receptors significantly decreases spontaneous activity in young Xenopus retina, but that blocking GABA(A) receptor blockers does not. Our findings indicate that vision drives correlated activity required for topographic map formation. They further suggest that developing retinal circuits in the two major subdivisions of tetrapods, amphibians and amniotes, evolved different strategies to supply appropriately patterned RGC activity to drive visual circuit refinement. Copyright © 2011 Wiley Periodicals, Inc.

  3. Direct localised measurement of electrical resistivity profile in rat and embryonic chick retinas using a microprobe

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    Harald van Lintel

    2010-01-01

    Full Text Available We report an alternative technique to perform a direct and local measurement of electrical resistivities in a layered retinal tissue. Information on resistivity changes along the depth in a retina is important for modelling retinal stimulation by retinal prostheses. Existing techniques for resistivity-depth profiling have the drawbacks of a complicated experimental setup, a less localised resistivity probing and/or lower stability for measurements. We employed a flexible microprobe to measure local resistivity with bipolar impedance spectroscopy at various depths in isolated rat and chick embryo retinas for the first time. Small electrode spacing permitted high resolution measurements and the probe flexibility contributed to stable resistivity profiling. The resistivity was directly calculated based on the resistive part of the impedance measured with the Peak Resistance Frequency (PRF methodology. The resistivity-depth profiles for both rat and chick embryo models are in accordance with previous mammalian and avian studies in literature. We demonstrate that the measured resistivity at each depth has its own PRF signature. Resistivity profiles obtained with our setup provide the basis for the construction of an electric model of the retina. This model can be used to predict variations in parameters related to retinal stimulation and especially in the design and optimisation of efficient retinal implants.

  4. The Endocannabinoid System in the Retina: From Physiology to Practical and Therapeutic Applications

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    Thomas Schwitzer

    2016-01-01

    Full Text Available Cannabis is one of the most prevalent drugs used in industrialized countries. The main effects of Cannabis are mediated by two major exogenous cannabinoids: ∆9-tetrahydroxycannabinol and cannabidiol. They act on specific endocannabinoid receptors, especially types 1 and 2. Mammals are endowed with a functional cannabinoid system including cannabinoid receptors, ligands, and enzymes. This endocannabinoid signaling pathway is involved in both physiological and pathophysiological conditions with a main role in the biology of the central nervous system. As the retina is a part of the central nervous system due to its embryonic origin, we aim at providing the relevance of studying the endocannabinoid system in the retina. Here, we review the distribution of the cannabinoid receptors, ligands, and enzymes in the retina and focus on the role of the cannabinoid system in retinal neurobiology. This review describes the presence of the cannabinoid system in critical stages of retinal processing and its broad involvement in retinal neurotransmission, neuroplasticity, and neuroprotection. Accordingly, we support the use of synthetic cannabinoids as new neuroprotective drugs to prevent and treat retinal diseases. Finally, we argue for the relevance of functional retinal measures in cannabis users to evaluate the impact of cannabis use on human retinal processing.

  5. Non-mydriatic video ophthalmoscope to measure fast temporal changes of the human retina

    Science.gov (United States)

    Tornow, Ralf P.; Kolář, Radim; Odstrčilík, Jan

    2015-07-01

    The analysis of fast temporal changes of the human retina can be used to get insight to normal physiological behavior and to detect pathological deviations. This can be important for the early detection of glaucoma and other eye diseases. We developed a small, lightweight, USB powered video ophthalmoscope that allows taking video sequences of the human retina with at least 25 frames per second without dilating the pupil. Short sequences (about 10 s) of the optic nerve head (20° x 15°) are recorded from subjects and registered offline using two-stage process (phase correlation and Lucas-Kanade approach) to compensate for eye movements. From registered video sequences, different parameters can be calculated. Two applications are described here: measurement of (i) cardiac cycle induced pulsatile reflection changes and (ii) eye movements and fixation pattern. Cardiac cycle induced pulsatile reflection changes are caused by changing blood volume in the retina. Waveform and pulse parameters like amplitude and rise time can be measured in any selected areas within the retinal image. Fixation pattern ΔY(ΔX) can be assessed from eye movements during video acquisition. The eye movements ΔX[t], ΔY[t] are derived from image registration results with high temporal (40 ms) and spatial (1,86 arcmin) resolution. Parameters of pulsatile reflection changes and fixation pattern can be affected in beginning glaucoma and the method described here may support early detection of glaucoma and other eye disease.

  6. Increased expression of IRE1α and stress-related signal transduction proteins in ischemia-reperfusion injured retina

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    Natsuyo Hata

    2008-08-01

    Full Text Available Natsuyo Hata1, Toshiyuki Oshitari1,2, Akiko Yokoyama1,3, Yoshinori Mitamura1, Shuichi Yamamoto11Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chuo-ku, Chiba, Japan; 2Department of Ophthalmology, Kimitsu Central Hospital, Kisarazu City, Chiba, Japan; 3Department of Ophthalmology, Inoue Memorial Hospital, Chuo-ku, Chiba, JapanAbstract: The purpose of this study was to determine whether the expression of ER stress-related factors IRE1α, apoptosis signal-regulating kinase 1 (ASK1, SAPK/ERK kinase 1 (SEK1 and c-Jun N-terminal kinase (JNK is associated with the damaged retinal neurons induced by ischemia-reperfusion injury. After 60 minutes of ischemia, the rat retinas were reperfused, and retinas were isolated and fixed after 6, 9, 12, 18, and 24 hours, and 2, 5, and 9 days of reperfusion. Cryosections were immunostained with Fluoro-Jade B, a degenerating neuron marker to label degenerating neurons. Semi-quantitative analysis of the expression of IRE1α, ASK1, SEK1, and JNK were performed in both control and ischemic retinas. In ischemic retinas, the intensities of IRE1α immunoreactivity in the ganglion cell layer (GCL were significantly higher than in the control retinas. In ischemic retinas, the numbers of SEK1-, ASK1-, and JNK-positive cells were significantly increased in the GCL compared to those in the control retinas. In addition, the cells that were positive for SEK1-, ASK1-, and JNK were also positive for Fluoro-Jade B-positive cells. These results indicate that the increased expression of ER stress-related factors was, in part, associated with the retinal neuronal abnormalities after ischemia-reperfusion injury in rat retinas.Keywords: endoplasmic reticulum, IRE1α, apoptosis signal-regulating kinase 1, SAPK/ERK kinase 1, c-Jun N-terminal kinase, Fluoro-Jade B, ischemia-reperfusion injury

  7. Common Variants in the COL4A4 Gene Confer Susceptibility to Lattice Degeneration of the Retina

    OpenAIRE

    Meguro, Akira; Ideta, Hidenao; Ota, Masao; Ito, Norihiko; Ideta, Ryuichi; Yonemoto, Junichi; Takeuchi, Masaki; Uemoto, Riyo; Nishide, Tadayuki; Iijima, Yasuhito; Kawagoe, Tatsukata; Okada, Eiichi; Shiota, Tomoko; Hagihara, Yuta; Oka, Akira

    2012-01-01

    Lattice degeneration of the retina is a vitreoretinal disorder characterized by a visible fundus lesion predisposing the patient to retinal tears and detachment. The etiology of this degeneration is still uncertain, but it is likely that both genetic and environmental factors play important roles in its development. To identify genetic susceptibility regions for lattice degeneration of the retina, we performed a genome-wide association study (GWAS) using a dense panel of 23,465 microsatellite...

  8. Tratamento da doença de Alzheimer: avaliação crítica sobre o uso de anticolinesterásicos Update on anticholinesterase treatment of Alzheimer's disease

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    OSVALDO P. ALMEIDA

    1998-09-01

    Full Text Available A demência do tipo Alzheimer (DA é uma doença degenerativa que há até pouco tempo não tinha nenhum tratamento eficaz. Pesquisas realizadas a partir da década de 70 revelaram que os sistemas cerebrais que utilizam acetilcolina encontram-se gravemente comprometidos nesses pacientes, o que serviu de base para a introdução da terapêutica de base colinérgica da doença. Os inibidores da acetilcolinesterase foram os primeiros medicamentos que demonstraram ser úteis para o tratamento da DA em ensaios clínicos controlados contra placebo. Este artigo revê os principais estudos desenhados para investigar a eficácia e efeitos adversos da tacrina, donepezil, rivastigmina, e metrifonato em pacientes com DA. Discutem-se, ainda, os fatores que podem interferir na resposta do paciente ao tratamento com anticolinesterásicos, bem como as limitações inerentes a esse tipo de abordagem terapêutica.Alzheimer's disease (AD is a neurogenerative disorder that had no effective treatment until a few years ago. Many studies published during the past 20 years showed that the disease is associated with the disruption of brain systems that use acetilcholine. These findings shaped the development of the cholinergic treatment strategies for AD. The cholinesterase inhibitors were the first class of drugs to show positive results in double-blind placebo controlled studies for the treatment of AD. This paper reviews efficacy and safety studies of tacrine, donepezil, rivastigmine, and metrifonate in patients with AD. Factors that may interfere with patients' response to treatment are also discussed, as well as the limitations associated with the use of this class of drugs.

  9. Morphological characterization and topographic analysis of multiple photoreceptor types in the retinae of mesopelagic hatchetfishes with tubular eyes

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    Lauren Michelle Biagioni

    2016-03-01

    Full Text Available Marine hatchetfishes, Argyropelecus spp., are one of the 14 genera of mesopelagic teleosts, which possess tubular eyes. The tubular eyes are positioned dorsally on the head and consist of a main retina, which subtends a large dorsal binocular field, and an accessory retina, which subtends the lateral monocular visual field. The topographic distribution of photoreceptors in the retina of Argyropelecus sladeni, A. affinis and A. aculeatus was determined using a random, unbiased and systematic stereological approach, which consistently revealed a region of high density (area centralis in the central region of the main retina (up to a peak of 96,000 receptors per mm2 and a relatively homogeneous density of photoreceptors in the accessory retina (of approximately 20,000 receptors per mm2. The position of the area centralis in the main retina indicates this retinal region subserves greater spatial resolution in the centre of the dorsal binocular visual field. Light microscopy and transmission electron microscopy also revealed the presence of multiple photoreceptor types (two rod-like and one cone-like based on the size and shape of the inner and outer segments and ultrastructural differences in the ellipsoidal region. The presence of multiple photoreceptor types in these tubular-eyed, mesopelagic hatchetfishes may reflect the need for the visual system to function under different lighting conditions during vertical migratory behavior, especially given their unique dorsally-facing eyes.

  10. Circulating Reactive Oxidant Causes Apoptosis of Retinal Pigment Epithelium and Cone Photoreceptors in the Mouse Central Retina

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    Wei Wang

    2011-01-01

    Full Text Available Reactive oxidants damage the retinal pigment epithelium (RPE, which is required for viability of overlying photoreceptors. Smoking which leads to chronic accumulation of reactive oxidants in the circulation is linked to age-related macular degeneration (AMD where RPE death is seen along with photoreceptor loss in the central macular region of the retina. It is unclear why this damage is concentrated in the central retina. We asked whether circulating oxidant might specifically target the central retina. Mice were administered the classic reactive oxidant iodate through tail vein injection, and visual acuity was followed by optokinetic response. Histology and apoptosis was examined by H&E and immunostaining. Iodate indeed selectively damaged the central retina, and this damage was highlighted by early apoptosis of RPE in the central retina followed by apoptosis of photoreceptors adjacent to the region of RPE loss–-cones were lost preferentially. The pattern and extent of this damage was independent of exposure to light. We then conclude that circulating oxidant is sufficient to selectively damage the central retina highlighted by sequential apoptosis of RPE and photoreceptors, with cones being the most sensitivity to this RPE loss.

  11. Mechanical Stress and Antioxidant Protection in the Retina of Hindlimb Suspended Rats

    Science.gov (United States)

    Glass, Aziza; Theriot, Corey A.; Alway, Stephen E.; Zanello, Susana B.

    2012-01-01

    It has been postulated that hindlimb suspension (HS) causes a cephalad fluid shift in quadrupeds similar to that occurring to humans in microgravity. Therefore, HS may provide a suitable animal model in which to recapitulate the ocular changes observed in the human Visual Impairment and Intracranial Pressure (VIIP) syndrome. This work reports preliminary results from a tissue sharing project using 34 week-old Brown Norway rats. Two different experiments compared normal posture controls and HS rats for 2 weeks and rats exposed to HS for 2 weeks but allowed to recover in normal posture for 2 additional weeks. The effects of two nutritional countermeasures, green tea extract (GT) and plant polyphenol resveratrol (Rv), were also evaluated. Green tea contains the antioxidant epigallocatechin gallate (EGCG). qPCR gene expression analysis of selected targets was performed on RNA from isolated retinas, and histologic analysis was done on one fixed eye per rat. The transcription factor early growth response protein 1 (Egr1) was upregulated almost 2-fold in HS retinas relative to controls (P = 0.059), and its expression returned to control levels after 2 weeks of recovery in normal posture (P = 0.023). HS-induced upregulation of Egr1 was attenuated (but not significantly) in retinas from rats fed an antioxidant rich (GT extract) diet. In rats fed the GT-enriched diet, antioxidant enzymes were induced, evidenced by the upregulation of the gene heme oxygenase 1 (Hmox1) (P = 0.042) and the gene superoxide dismutase 2 (Sod2) (P = 0.0001). Egr1 is a stretch-activated transcription factor, and the Egr1 mechanosensitive response to HS may have been caused by a change in the translaminal pressure and/or mechanical deformation of the eye globe. The observed histologic measurements of the various retinal layers in the HS rats were lower in value than those of the control animal (n = 1), however insufficient data were available for statistical analysis. Aquaporin 4, a water

  12. Characterisation of the metabolome of ocular tissues and post-mortem changes in the rat retina.

    Science.gov (United States)

    Tan, Shi Z; Mullard, Graham; Hollywood, Katherine A; Dunn, Warwick B; Bishop, Paul N

    2016-08-01

    Time-dependent post-mortem biochemical changes have been demonstrated in donor cornea and vitreous, but there have been no published studies to date that objectively measure post-mortem changes in the retinal metabolome over time. The aim of the study was firstly, to investigate post-mortem, time-dependent changes in the rat retinal metabolome and secondly, to compare the metabolite composition of healthy rat ocular tissues. To study post-mortem changes in the rat retinal metabolome, globes were enucleated and stored at 4 °C and sampled at 0, 2, 4, 8, 24 and 48 h post-mortem. To study the metabolite composition of rat ocular tissues, eyes were dissected immediately after culling to isolate the cornea, lens, vitreous and retina, prior to storing at -80 °C. Tissue extracts were subjected to Gas Chromatograph Mass Spectrometry (GC-MS) and Ultra High Performance Liquid Chromatography Mass Spectrometry (UHPLC-MS). Generally, the metabolic composition of the retina was stable for 8 h post-mortem when eyes were stored at 4 °C, but showed increasing changes thereafter. However, some more rapid changes were observed such as increases in TCA cycle metabolites after 2 h post-mortem, whereas some metabolites such as fatty acids only showed decreases in concentration from 24 h. A total of 42 metabolites were identified across the ocular tissues by GC-MS (MSI level 1) and 2782 metabolites were annotated by UHPLC-MS (MSI level 2) according to MSI reporting standards. Many of the metabolites detected were common to all of the tissues but some metabolites showed partitioning between different ocular structures with 655, 297, 93 and 13 metabolites being uniquely detected in the retina, lens, cornea and vitreous respectively. Only a small percentage (1.6%) of metabolites found in the vitreous were only detected in the retina and not other tissues. In conclusion, mass spectrometry-based techniques have been used for the first time to compare the metabolic composition of

  13. Changes in acetylcholine release from the chick retina are not associated with myopia development

    International Nuclear Information System (INIS)

    Vessey, K.A.; Cotriall, C.L.; McBrien, N.A.

    2002-01-01

    Full text: The effectiveness of muscarinic receptor antagonists in inhibiting myopia progression in animal models and humans implicates cholinergic signalling in ocular growth regulation. Therefore to determine if changes in the release of acetylcholine from the retina are involved in myopia development, the efflux of acetylcholine from the in vitro retina of normal and myopic chick eyes was investigated. Chicks were monocularly deprived (MD) of pattern vision with translucent occluders for 2 or 7 days and refractive error of MD groups and age matched normals was monitored using retinoscopy (n=6 each group). 3 H-choline-Cl (1 Ci in 7μL) was injected into the vitreous of each eye under 2.5% halothane anaesthesia. After 1hr, the eyes were enucleated, under terminal anaesthesia (sodium pentobarbital, 120 mg/kg, im). Retinas were flat-mounted on acetate filter discs and superfused with oxygenated physiological saline solution (PSS) for 30min at 0.4mL/min. Five baseline fractions were collected (B1-B5), then three stimulated fractions were collected in the presence of PSS containing 50mM KCl (K1-K3) at 2min intervals. 3 H-acetylcholine ( 3 H-ACh) in each fraction was quantified by liquid scintillation counting. Significant amounts of myopia were induced in MD eyes after 2 (-5.1±0.8D) and 7 days (-18.8±2.4D) relative to control eyes (paired t-test p 3 H-ACh release was 146±15% above basal levels (K2/B1%) from retinas of normal animals. After 2 days MD, there was no significant difference between KCl-evoked release of 3 H-ACh from deprived eyes (147 39%) compared to control eyes (198±61%, paired t-test, p=0.27) or the eyes of normal animals (ANOVA, p>0.5). Similar results were obtained following 7 days MD. The results demonstrate that evoked acetylcholine release from the chick retina of myopic eyes is unaltered relative to control or normal eyes using an in vitro approach. Copyright (2002) Australian Neuroscience Society

  14. La retina para el médico no oftalmólogo

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    Clara Leonor Varón Plata, MD

    2010-01-01

    Full Text Available La retina es un tejido fundamental en el órgano de la visión.En este artículo hacemos una revisión sobre la anatomía yfisiología de esta estructura así como sobre las principalespatologías que la pueden afectar, entre ellas: despren-dimiento de retina, retinopatía diabética y la enfermedadmacular relacionada con la edad. Aunque actualmentecontamos con técnicas médicas y quirúrgicas seguras yefectivas para el manejo de estas patologías, aúnrepresentan un reto para la ciencia médica, y en estadosavanzados comprometen seriamente la función visual, porello es de gran importancia que el médico general tengaclaros los conceptos básicos sobre el diagnóstico de estasenfermedades, para realizar una remisión adecuada y así poder evitar al máximo secuelas visuales en el paciente. En este artículo revisamos libros de texto reconocidos y empleando MEDLINE, algunos artículos representativos sobre este tema, para mostrar un panorama general del estado actual, clínico e investigativo, del diagnóstico y tratamientode las enfermedades más importantes que afectan la retina y el vítreo. ______________________________________________________________________The retina is a fundamental tissue of the visual organ. In this article we make a review of the anatomy and physiology of this structure as well as the main pathologies that may affect it like: retinal detachment, diabetic retinopathy, and age related macular degeneration. Although currently there are safe medical and surgical alternatives for the management of these diseases, they still represent a challenge for the medical science, and in advanced stagesthey seriously compromise visual function. For this reason it is of vital importance that the primary care physician has clear concepts about the diagnosis of these diseases, to perform an adequate referral, avoiding visual sequelae as much as possible. In this article we reviewed recognized textbooks and using MEDLINE we found some

  15. Excess lead in the neural retina in age-related macular degeneration.

    Science.gov (United States)

    Erie, Jay C; Good, Jonathan A; Butz, John A

    2009-12-01

    To measure lead and cadmium in retinal tissues of human donor eyes with and without age-related macular degeneration (AMD). Laboratory investigation. Lead and cadmium concentrations in retinal tissues (neural retina and retinal pigment epithelium [RPE]-choroid complex) in 25 subjects with AMD (50 donor eyes) and 36 normal subjects (72 donor eyes) were determined by using inductively coupled plasma-mass spectrometry. Severity of AMD was graded by using color fundus photographs and the Minnesota Grading System. Differences in metal concentrations were compared by using Wilcoxon rank-sum tests. The neural retinas of subjects with AMD had increased lead concentrations (median, 12.0 ng/g; 25% to 75% interquartile range, 8 to 18 ng/g; n = 25) compared with normal subjects (median, 8.0 ng/g; 25% to 75% interquartile range, 0 to 11 ng/g; P = .04; n = 36). There was no difference in lead concentration in the RPE-choroid complex between subjects with AMD (median, 198 ng/g; 25% to 75% interquartile range, 87 to 381 ng/g) and normal subjects (median, 172 ng/g; 25% to 75% interquartile range, 100 to 288 ng/g; P = .25). Cadmium concentration in the neural retina (median, 0.9 microg/g; 25% to 75% interquartile range, 0.7 to 1.8 microg/g) and RPE-choroid complex (median, 2.2 microg/g; 25% to 75% interquartile range, 1.8 to 3.7 microg/g) in subjects with AMD was not different from concentrations in the neural retina (median, 0.9 microg/g; 25% to 75% interquartile range, 0.7 to 1.4 microg/g; P = .32) and RPE-choroid complex (median, 1.5 microg/g; 25% to 75% interquartile range, 0.9 to 2.5 microg/g; P = .12) of normal subjects. AMD is associated with excess lead in the neural retina, and this relationship suggests that metal homeostasis in AMD eyes is different from normal.

  16. Caracterização da patologia cerebral, da psicopatologia e da heredologia psiquiátrica na doutrina de Kleist

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    Aníbal Silveira

    1959-06-01

    Full Text Available O ano de 1959 assinala três datas especiais em uma das mais férteis carreiras científicas: completa 80 anos Karl Kleist, nascido em Mülhausen, na Alsácia, a 31 de janeiro de 1879, que comemora o jubileu de venia legendi (1909; e há um quarto de século veio à luz a Gehirnpathologie (1934, que marca a nova era da fisiopatologia cerebral. A construção doutrinária de Kleist combina e aperfeiçoa as diretrizes isoladas de Meynert, de Wernicke e de Kraepelin. Constitui nela uma constante a união da psicopatologia à patologia cerebral; e a pesquisa no domínio clínico se norteia pela patogenia, pela heredologia e pela catamnese sistemática. Na própria patogênese - tanto dos quadros clínicos como dos sintomas - há a considerar a diferente participação do tronco cerebral e da corticalidade. E aqui, a seu turno, é preciso distinguir as funções que dependem de regiões posteriores. Assim, descreveu Kleist, respectivamente, os distúrbios agramáticos e os paragramáticos, os alógicos e os paralógicos, em analogia com os afásicos e os parafásicos. Demonstrou pela primeira vez, em 1905, a existência da afasia de condução e isolou dois novos tipos de apraxia: a apraxia segmentar e a apraxia de construção. Outros quadros psicopatológicos descritos por êle também se tornaram clássicos: a carência de iniciativa, a apraxia de iniciativa, a apraxia de ação coordenada (Handlungsfolge, a cegueira espacial (Ortsblindheit, a agnosia cromática - que depende da noção abstrata de côr e nada tem a ver com o daltonismo - e ainda os quadros psiquiátricos cíngulo-orbitários. Divide a esfera da personalidade em diversos estratos de grande relevância clínico-localizatória (quadro 1. A carta localizatória - plano estrutural e funcional do cérebro - ultrapassa a qualquer empreendimento análogo, tanto pela análise penetrante quanto pela adaptação à realidade clínica (figs. 1 e 2. Sobreleva notar aí que Kleist separa

  17. Perfluoroctano líquido como tamponante vitreorretiniano de curta duração no pós-operatório de portadores de descolamento de retina por ruptura gigante Perfluoroctane liquid as a short-term vitreous-retinal tamponade in the postoperative period in patients with retinal detachment due to giant tears

    Directory of Open Access Journals (Sweden)

    Marcelo Carvalho Ventura

    2007-06-01

    Full Text Available OBJETIVOS: Relatar os resultados de vitrectomia via pars plana com utilização de perfluocarbono líquido (Perfluoroctano-Ophtalmos®, como tamponante vítreo-retiniano de curta duração, no pós-operatório de portadores de descolamento de retina, por ruptura gigante. MÉTODOS: Estudaram-se dez desses pacientes. Todos os casos eram complicados por vitreorretinopatia proliferativa grau B ou pior com rupturas que variavam em extensão de 90º a 210º. O perfluorocarbono líquido foi introduzido, por via pars plana, com o volume necessário para ultrapassar o limite posterior da ruptura, permanecendo no pós-operatório por cinco dias, estando os pacientes em decúbito dorsal. Após esse período submetiam-se a segunda intervenção para troca do perfluorocarbono líquido para gás ou óleo de silicone. RESULTADOS: Após período de acompanhamento médio de 16,2 ± 12,4 meses (2 a 43 meses, 80% das retinas estavam aplicadas, sendo necessária a repetição desta técnica em 1 caso (10% caso e em 2 casos (20% não houve reaplicação da retina por vitreorretinopatia avançada. Houve melhora da acuidade visual em 5 casos (50%. CONCLUSÃO: Observaram-se bons resultados quanto à aplicação da retina (80% e melhora da acuidade visual (50% quando do uso do perfluorocarbono líquido como tamponante vitreorretiniano de curta duração no pós-operatório de cirurgias de descolamento de retina por rupturas gigantes.PURPOSE: To report pars plana vitrectomy results of intravitreous use of liquid perfluorocarbon as a short-term postoperative tamponade in retinal detachment due to giant tears in a series of patients. METHODS: Ten of those patients, all of them complicated by proliferative vitreoretinopathy grade B or worse, with tear extension varying from 90º to 210º were studied. Perfluorocarbon liquid was injected via pars plana until the posterior tear limit, remaining in the postoperative period during five days, with the patients in supine position

  18. Alterations in energy metabolism, neuroprotection and visual signal transduction in the retina of Parkinsonian, MPTP-treated monkeys.

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    Laura Campello

    Full Text Available Parkinson disease is mainly characterized by the degeneration of dopaminergic neurons in the central nervous system, including the retina. Different interrelated molecular mechanisms underlying Parkinson disease-associated neuronal death have been put forward in the brain, including oxidative stress and mitochondrial dysfunction. Systemic injection of the proneurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP to monkeys elicits the appearance of a parkinsonian syndrome, including morphological and functional impairments in the retina. However, the intracellular events leading to derangement of dopaminergic and other retinal neurons in MPTP-treated animal models have not been so far investigated. Here we have used a comparative proteomics approach to identify proteins differentially expressed in the retina of MPTP-treated monkeys. Proteins were solubilized from the neural retinas of control and MPTP-treated animals, labelled separately with two different cyanine fluorophores and run pairwise on 2D DIGE gels. Out of >700 protein spots resolved and quantified, 36 were found to exhibit statistically significant differences in their expression levels, of at least ± 1.4-fold, in the parkinsonian monkey retina compared with controls. Most of these spots were excised from preparative 2D gels, trypsinized and subjected to MALDI-TOF MS and LC-MS/MS analyses. Data obtained were used for protein sequence database interrogation, and 15 different proteins were successfully identified, of which 13 were underexpressed and 2 overexpressed. These proteins were involved in key cellular functional pathways such as glycolysis and mitochondrial electron transport, neuronal protection against stress and survival, and phototransduction processes. These functional categories underscore that alterations in energy metabolism, neuroprotective mechanisms and signal transduction are involved in MPTP-induced neuronal degeneration in the retina, in similarity to

  19. Transcriptomic analysis across nasal, temporal, and macular regions of human neural retina and RPE/choroid by RNA-Seq

    Science.gov (United States)

    Whitmore, S. Scott; Wagner, Alex H.; DeLuca, Adam P.; Drack, Arlene V.; Stone, Edwin M.; Tucker, Budd A.; Zeng, Shemin; Braun, Terry A.; Mullins, Robert F.; Scheetz, Todd E.

    2014-01-01

    Proper spatial differentiation of retinal cell types is necessary for normal human vision. Many retinal diseases, such as Best disease and male germ cell associated kinase (MAK)-associated retinitis pigmentosa, preferentially affect distinct topographic regions of the retina. While much is known about the distribution of cell-types in the retina, the distribution of molecular components across the posterior pole of the eye has not been well-studied. To investigate regional difference in molecular composition of ocular tissues, we assessed differential gene expression across the temporal, macular, and nasal retina and retinal pigment epithelium (RPE)/choroid of human eyes using RNA-Seq. RNA from temporal, macular, and nasal retina and RPE/choroid from four human donor eyes was extracted, poly-A selected, fragmented, and sequenced as 100 bp read pairs. Digital read files were mapped to the human genome and analyzed for differential expression using the Tuxedo software suite. Retina and RPE/choroid samples were clearly distinguishable at the transcriptome level. Numerous transcription factors were differentially expressed between regions of the retina and RPE/choroid. Photoreceptor-specific genes were enriched in the peripheral samples, while ganglion cell and amacrine cell genes were enriched in the macula. Within the RPE/choroid, RPE-specific genes were upregulated at the periphery while endothelium associated genes were upregulated in the macula. Consistent with previous studies, BEST1 expression was lower in macular than extramacular regions. The MAK gene was expressed at lower levels in macula than in extramacular regions, but did not exhibit a significant difference between nasal and temporal retina. The regional molecular distinction is greatest between macula and periphery and decreases between different peripheral regions within a tissue. Datasets such as these can be used to prioritize candidate genes for possible involvement in retinal diseases with

  20. Transcriptomic analysis across nasal, temporal, and macular regions of human neural retina and RPE/choroid by RNA-Seq.

    Science.gov (United States)

    Whitmore, S Scott; Wagner, Alex H; DeLuca, Adam P; Drack, Arlene V; Stone, Edwin M; Tucker, Budd A; Zeng, Shemin; Braun, Terry A; Mullins, Robert F; Scheetz, Todd E

    2014-12-01

    Proper spatial differentiation of retinal cell types is necessary for normal human vision. Many retinal diseases, such as Best disease and male germ cell associated kinase (MAK)-associated retinitis pigmentosa, preferentially affect distinct topographic regions of the retina. While much is known about the distribution of cell types in the retina, the distribution of molecular components across the posterior pole of the eye has not been well-studied. To investigate regional difference in molecular composition of ocular tissues, we assessed differential gene expression across the temporal, macular, and nasal retina and retinal pigment epithelium (RPE)/choroid of human eyes using RNA-Seq. RNA from temporal, macular, and nasal retina and RPE/choroid from four human donor eyes was extracted, poly-A selected, fragmented, and sequenced as 100 bp read pairs. Digital read files were mapped to the human genome and analyzed for differential expression using the Tuxedo software suite. Retina and RPE/choroid samples were clearly distinguishable at the transcriptome level. Numerous transcription factors were differentially expressed between regions of the retina and RPE/choroid. Photoreceptor-specific genes were enriched in the peripheral samples, while ganglion cell and amacrine cell genes were enriched in the macula. Within the RPE/choroid, RPE-specific genes were upregulated at the periphery while endothelium associated genes were upregulated in the macula. Consistent with previous studies, BEST1 expression was lower in macular than extramacular regions. The MAK gene was expressed at lower levels in macula than in extramacular regions, but did not exhibit a significant difference between nasal and temporal retina. The regional molecular distinction is greatest between macula and periphery and decreases between different peripheral regions within a tissue. Datasets such as these can be used to prioritize candidate genes for possible involvement in retinal diseases with

  1. Light-modulated release of RFamide-like neuropeptides from nervus terminalis axon terminals in the retina of goldfish.

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    Fischer, A J; Stell, W K

    1997-03-01

    The nervus terminalis of teleosts, a cranial nerve anatomically associated with the olfactory system, projects to visual system targets including retina and optic tectum. It is known to contain gonadotropin-releasing hormone and RFamide-like peptides, but its function remains unknown. We have probed nervus terminalis function in goldfish by measuring peptide content in retina and tectum with a radioimmunoassay for A18Famide (neuropeptide AF; bovine morphine-modulating peptide). We found that retinal peptide content increased in the dark and decreased in the light, whereas tectal peptide content decreased in the dark and increased in the light. In addition, RFamide-like peptide content in the retina was transiently decreased by severing both olfactory tracts, increased in light-adapted eyes treated with a GABAergic agonist (isoguvacine), and decreased in dark-adapted eyes treated with GABAergic antagonists (bicuculline and picrotoxin). We also found that RFamide-like peptide release could be induced in dark-adapted isolated-superfused retinas by exposure to light or a high concentration (102.5 mM) of potassium ions. We interpret the increase and decrease in peptide content as reflecting a decrease and increase, respectively, in rate of peptide release. We propose that the release and accumulation of RFamide-like peptides in axon terminals of nervus terminalis processes in the retina are modulated primarily by neurons intrinsic to the retina and regulated by light. Peptide release appears to be inhibited tonically in the dark by GABA acting through GABAA receptors; light facilitates peptide release by disinhibition due to a reduction in GABA release. In addition, we propose that electrical signals originating outside the retina can override these intrinsic release-modulating influences.

  2. Cannabinoid Receptor Type 1 Expression in the Developing Avian Retina: Morphological and Functional Correlation With the Dopaminergic System

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    Luzia da Silva Sampaio

    2018-03-01

    Full Text Available The avian retina has been used as a model to study signaling by different neuro- and gliotransmitters. It is unclear how dopaminergic and cannabinoid systems are related in the retina. Here we studied the expression of type 1 and 2 cannabinoid receptors (CB1 and CB2, as well as monoacylglycerol lipase (MAGL, the enzyme that degrades 2-arachidonoylglycerol (2-AG, during retina development. Our data show that CB1 receptor is highly expressed from embryonic day 5 (E5 until post hatched day 7 (PE7, decreasing its levels throughout development. CB1 is densely found in the ganglion cell layer (GCL and inner plexiform layer (IPL. CB2 receptor was also found from E5 until PE7 with a decrease in its contents from E9 afterwards. CB2 was mainly present in the lamination of the IPL at PE7. MAGL is expressed in all retinal layers, mainly in the IPL and OPL from E9 to PE7 retina. CB1 and CB2 were found both in neurons and glia cells, but MAGL was only expressed in Müller glia. Older retinas (PE7 show CB1 positive cells mainly in the INL and co-expression of CB1 and tyrosine hydroxylase (TH are shown in a few cells when both systems are mature. CB1 co-localized with TH and was heavily associated to D1 receptor labeling in primary cell cultures. Finally, cyclic AMP (cAMP was activated by the selective D1 agonist SKF38393, and inhibited when cultures were treated with WIN55, 212–2 (WIN in a CB1 dependent manner. The results suggest a correlation between the endocannabinoid and dopaminergic systems (DSs during the avian retina development. Activation of CB1 limits cAMP accumulation via D1 receptor activation and may influence embryological parameters during avian retina differentiation.

  3. Localization of glycine-containing neurons in the Macaca monkey retina

    International Nuclear Information System (INIS)

    Hendrickson, A.E.; Koontz, M.A.; Pourcho, R.G.; Sarthy, P.V.; Goebel, D.J.

    1988-01-01

    Autoradiography following 3H-glycine (Gly) uptake and immunocytochemistry with a Gly-specific antiserum were used to identify neurons in Macaca monkey retina that contain a high level of this neurotransmitter. High-affinity uptake of Gly was shown to be sodium dependent whereas release of both endogenous and accumulated Gly was calcium dependent. Neurons labeling for Gly included 40-46% of the amacrine cells and nearly 40% of the bipolars. Synaptic labeling was seen throughout the inner plexiform layer (IPL) but with a preferential distribution in the inner half. Bands of labeled puncta occurred in S2, S4, and S5. Both light and postembedding electron microscopic (EM) immunocytochemistry identified different types of amacrine and bipolar cell bodies and their synaptic terminals. The most heavily labeled Gly+ cell bodies typically were amacrine cells having a single, thick, basal dendrite extending deep into the IPL and, at the EM level, electron-dense cytoplasm and prominent nuclear infoldings. This cell type may be homologous with the Gly2 cell in human retina and the AII/Gly2 of cat retina. Gly+ amacrines synapse most frequently onto Gly- amacrines and both Gly- and Gly+ bipolars. Gly+ bipolar cells appeared to be cone bipolars because their labeled dendrites could be traced only to cone pedicles. The pattern of these labeled dendritic trees indicated that both diffuse and midget types of biopolars were Gly+. The EM distribution of labeled synapses showed Gly+ amacrine synapses throughout the IPL, but these composed only 11-23% of the amacrine population. Most of the Gly+ bipolar terminals were in the inner IPL, where 70% of all bipolar terminals were labeled

  4. Adaptation in Coding by Large Populations of Neurons in the Retina

    Science.gov (United States)

    Ioffe, Mark L.

    A comprehensive theory of neural computation requires an understanding of the statistical properties of the neural population code. The focus of this work is the experimental study and theoretical analysis of the statistical properties of neural activity in the tiger salamander retina. This is an accessible yet complex system, for which we control the visual input and record from a substantial portion--greater than a half--of the ganglion cell population generating the spiking output. Our experiments probe adaptation of the retina to visual statistics: a central feature of sensory systems which have to adjust their limited dynamic range to a far larger space of possible inputs. In Chapter 1 we place our work in context with a brief overview of the relevant background. In Chapter 2 we describe the experimental methodology of recording from 100+ ganglion cells in the tiger salamander retina. In Chapter 3 we first present the measurements of adaptation of individual cells to changes in stimulation statistics and then investigate whether pairwise correlations in fluctuations of ganglion cell activity change across different stimulation conditions. We then transition to a study of the population-level probability distribution of the retinal response captured with maximum-entropy models. Convergence of the model inference is presented in Chapter 4. In Chapter 5 we first test the empirical presence of a phase transition in such models fitting the retinal response to different experimental conditions, and then proceed to develop other characterizations which are sensitive to complexity in the interaction matrix. This includes an analysis of the dynamics of sampling at finite temperature, which demonstrates a range of subtle attractor-like properties in the energy landscape. These are largely conserved when ambient illumination is varied 1000-fold, a result not necessarily apparent from the measured low-order statistics of the distribution. Our results form a consistent

  5. Expression of neurotransmitters and neurotrophins in neurogenic inflammation of the rat retina

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    E Bronzetti

    2009-08-01

    Full Text Available Antidromic stimulation of the rat trigeminal ganglion triggers the release of substance P (SP and calcitonin gene-related peptide (CGRP from sensory nerve terminals of the capsaicin sensitive C-fibers. These pro-inflammatory neuropeptides produce a marked hyperemia in the anterior segment of the eye, accompanied by increased intraocular pressure, breakdown of the blood-aqueous barrier and myosis. To assess the effects of neurogenic inflammation on the retina, specifically on the immunostaining of neurotransmitters and neurotrophins, as well as on the expression of neurotrophin receptors in the retina. RT-PCR was also accomplished in control and stimulated animals to confirm the immunohistochemical results. In the electrically stimulated eyes, immunostaining for SP, CGRP, VIP and nNOS demonstrated a marked increase in the RPE/POS (Retinal Pigment Epithelium/Photoreceptor Outer Segments, in the inner and outer granular layers and in the ganglion cells in comparison to the control eyes. CGRP and SP were found increased in stimulated animals and this result has been confirmed by RT- PCR. Changes in neurotrophin immunostaining and in receptor expression were also observed after electric stimulation of trigeminal ganglia. Decrease of BDNF and NT4 in the outer and inner layers and in ganglion cells was particularly marked. In stimulated rat retinas immunostaining and RT-PCR showed a NGF expression increase. Neurotrophin receptors remained substantially unchanged. These studies demonstrated, for the first time, that antidromic stimulation of the trigeminal ganglion and subsequent neurogenic inflammation affect immunostaining of retinal cell neurotransmitter/ neuropeptides and neurotrophins as well as the expression of neurotrophin receptors.

  6. Localization of diacylglycerol lipase alpha and monoacylglycerol lipase during postnatal development of the rat retina

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    Bruno eCécyre

    2014-12-01

    Full Text Available In recent decades, there has been increased interest in the physiological roles of the endocannabinoid (eCB system and its receptors, the cannabinoid receptor types 1 (CB1R and 2 (CB2R. Exposure to cannabinoids during development results in neurofunctional alterations, which implies that the eCB system is involved in the developmental processes of the brain. Because of their lipophilic nature, eCBs are synthesized on demand and are not stored in vesicles. Consequently, the enzymes responsible for their synthesis and degradation are key regulators of their physiological actions. Therefore, knowing the localization of these enzymes during development is crucial for a better understanding of the role played by eCBs during the formation of the central nervous system.In this study, we investigated the developmental protein localization of the synthesizing and catabolic enzymes of the principal eCB, 2-arachidonoylglycerol (2-AG in the retinas of young and adult rats. The distribution of the enzymes responsible for the synthesis (DAGLα and the degradation (MAGL of 2-AG was determined for every retinal cell type from birth to adulthood. Our results indicate that DAGLα is present early in postnatal development. It is highly expressed in photoreceptor, horizontal, amacrine, and ganglion cells. MAGL appears later during the development of the retina and its presence is limited to amacrine and Müller cells. Overall, these results suggest that 2-AG is strongly present in early retinal development and might be involved in the regulation of the structural and functional maturation of the retina.

  7. An autonomous circadian clock in the inner mouse retina regulated by dopamine and GABA.

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    Guo-Xiang Ruan

    2008-10-01

    Full Text Available The influence of the mammalian retinal circadian clock on retinal physiology and function is widely recognized, yet the cellular elements and neural regulation of retinal circadian pacemaking remain unclear due to the challenge of long-term culture of adult mammalian retina and the lack of an ideal experimental measure of the retinal circadian clock. In the current study, we developed a protocol for long-term culture of intact mouse retinas, which allows retinal circadian rhythms to be monitored in real time as luminescence rhythms from a PERIOD2::LUCIFERASE (PER2::LUC clock gene reporter. With this in vitro assay, we studied the characteristics and location within the retina of circadian PER2::LUC rhythms, the influence of major retinal neurotransmitters, and the resetting of the retinal circadian clock by light. Retinal PER2::LUC rhythms were routinely measured from whole-mount retinal explants for 10 d and for up to 30 d. Imaging of vertical retinal slices demonstrated that the rhythmic luminescence signals were concentrated in the inner nuclear layer. Interruption of cell communication via the major neurotransmitter systems of photoreceptors and ganglion cells (melatonin and glutamate and the inner nuclear layer (dopamine, acetylcholine, GABA, glycine, and glutamate did not disrupt generation of retinal circadian PER2::LUC rhythms, nor did interruption of intercellular communication through sodium-dependent action potentials or connexin 36 (cx36-containing gap junctions, indicating that PER2::LUC rhythms generation in the inner nuclear layer is likely cell autonomous. However, dopamine, acting through D1 receptors, and GABA, acting through membrane hyperpolarization and casein kinase, set the phase and amplitude of retinal PER2::LUC rhythms, respectively. Light pulses reset the phase of the in vitro retinal oscillator and dopamine D1 receptor antagonists attenuated these phase shifts. Thus, dopamine and GABA act at the molecular level of PER

  8. Developmental and adult characterization of secretagogin expressing amacrine cells in zebrafish retina.

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    Stefanie Dudczig

    Full Text Available Calcium binding proteins show stereotypical expression patterns within diverse neuron types across the central nervous system. Here, we provide a characterization of developmental and adult secretagogin-immunolabelled neurons in the zebrafish retina with an emphasis on co-expression of multiple calcium binding proteins. Secretagogin is a recently identified and cloned member of the F-hand family of calcium binding proteins, which labels distinct neuron populations in the retinas of mammalian vertebrates. Both the adult distribution of secretagogin labeled retinal neurons as well as the developmental expression indicative of the stage of neurogenesis during which this calcium binding protein is expressed was quantified. Secretagogin expression was confined to an amacrine interneuron population in the inner nuclear layer, with monostratified neurites in the center of the inner plexiform layer and a relatively regular soma distribution (regularity index > 2.5 across central-peripheral areas. However, only a subpopulation (~60% co-labeled with gamma-aminobutyric acid as their neurotransmitter, suggesting that possibly two amacrine subtypes are secretagogin immunoreactive. Quantitative co-labeling analysis with other known amacrine subtype markers including the three main calcium binding proteins parvalbumin, calbindin and calretinin identifies secretagogin immunoreactive neurons as a distinct neuron population. The highest density of secretagogin cells of ~1800 cells / mm2 remained relatively evenly along the horizontal meridian, whilst the density dropped of to 125 cells / mm2 towards the dorsal and ventral periphery. Thus, secretagogin represents a new amacrine label within the zebrafish retina. The developmental expression suggests a possible role in late stage differentiation. This characterization forms the basis of functional studies assessing how the expression of distinct calcium binding proteins might be regulated to compensate for the loss

  9. Tumor vasoproliferativo de retina.: Reporte de dos casos Vasoproliferative retinal tumor.: Report of two cases

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    Danaides Arencibia González

    2010-12-01

    Full Text Available El tumor vasoproliferativo de retina es una condición rara y benigna que presenta una lesión exudativa de retina periférica. La lesión puede ser clasificada en primaria (idiopática o secundaria a otros procesos oculares. Las opciones terapéuticas incluyen observación, crioablación tisular, fotocoagulación láser, remoción quirúrgica mediante vitrectomía, terapia fotodinámica y braquiterapia epiescleral con isótopos radioactivos, asociadas o no al uso de antiangiogénicos o antiinflamatorios, siendo la elección de la modalidad de manejo particular en cada caso. Presentamos dos casos en pacientes femeninas portadoras de esta condición de los que describimos las características más importantes del cuadro clínico, retinografías, angiografía fluoresceínica y ecografía, así como el manejo y curso evolutivo-terapéutico.Vasoproliferative retinal tumor is a rare and benign condition that presents as an exudative lesion in the peripheral retina. The lesion can be classified in primary (idiopathic or secondary to other ocular processes. Therapeutic options include observation, cryotherapy, laser photocoagulation, surgical removal by pars plana vitrectomy, photodynamic therapy and epiescleral brachytheraphy with radio-active isotopes associated or not to the use of anti-angiogenic or anti-inflammatory drugs. The selection of a particular management modality depends on the type of case. Two female patients affected with this condition were presented; the most important characteristics in their clinical pictures, as well as the results of other tests as retinography, fluorescent and ICG angiography and echography were described. The management and the therapeutical and evolutive course of both patients were also discussed.

  10. Designing and testing scene enhancement algorithms for patients with retina degenerative disorders

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    Downes Susan M

    2010-06-01

    Full Text Available Abstract Background Retina degenerative disorders represent the primary cause of blindness in UK and in the developed world. In particular, Age Related Macular Degeneration (AMD and Retina Pigmentosa (RP diseases are of interest to this study. We have therefore created new image processing algorithms for enhancing the visual scenes for them. Methods In this paper we present three novel image enhancement techniques aimed at enhancing the remaining visual information for patients suffering from retina dystrophies. Currently, the only effective way to test novel technology for visual enhancement is to undergo testing on large numbers of patients. To test our techniques, we have therefore built a retinal image processing model and compared the results to data from patient testing. In particular we focus on the ability of our image processing techniques to achieve improved face detection and enhanced edge perception. Results Results from our model are compared to actual data obtained from testing the performance of these algorithms on 27 patients with an average visual acuity of 0.63 and an average contrast sensitivity of 1.22. Results show that Tinted Reduced Outlined Nature (TRON and Edge Overlaying algorithms are most beneficial for dynamic scenes such as motion detection. Image Cartoonization was most beneficial for spatial feature detection such as face detection. Patient's stated that they would most like to see Cartoonized images for use in daily life. Conclusions Results obtained from our retinal model and from patients show that there is potential for these image processing techniques to improve visual function amongst the visually impaired community. In addition our methodology using face detection and efficiency of perceived edges in determining potential benefit derived from different image enhancement algorithms could also prove to be useful in quantitatively assessing algorithms in future studies.

  11. Disruption of Fractalkine Signaling Leads to Microglial Activation and Neuronal Damage in the Diabetic Retina

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    Sandra M. Cardona

    2015-10-01

    Full Text Available Fractalkine (CX3CL1 or FKN is a membrane-bound chemokine expressed on neuronal membranes and is proteolytically cleaved to shed a soluble chemoattractant domain. FKN signals via its unique receptor CX3CR1 expressed on microglia and other peripheral leukocytes. The aim of this study is to determine the role of CX3CR1 in inflammatory-mediated damage to retinal neurons using a model of diabetic retinopathy. For this, we compared neuronal, microglial, and astroglial densities and inflammatory response in nondiabetic and diabetic (Ins2Akita CX3CR1-wild-type and CX3CR1-deficient mice at 10 and 20 weeks of age. Our results show that Ins2Akita CX3CR1-knockout mice exhibited (a decreased neuronal cell counts in the retinal ganglion cell layer, (b increased microglial cell numbers, and (c decreased astrocyte responses comparable with Ins2Akita CX3CR1-Wild-type mice at 20 weeks of age. Analyses of the inflammatory response using PCR arrays showed several inflammatory genes differentially regulated in diabetic tissues. From those, the response in Ins2Akita CX3CR1-deficient mice at 10 weeks of age revealed a significant upregulation of IL-1β at the transcript level that was confirmed by enzyme-linked immunosorbent assay in soluble retinal extracts. Overall, IL-1β, VEGF, and nitrite levels as a read out of nitric oxide production were abundant in Ins2Akita CX3CR1-deficient retina. Notably, double immunofluorescence staining shows that astrocytes act as a source of IL-1β in the Ins2Akita retina, and CX3CR1-deficient microglia potentiate the inflammatory response via IL-1β release. Collectively, these data demonstrate that dysregulated microglial responses in absence of CX3CR1 contribute to inflammatory-mediated damage of neurons in the diabetic retina.

  12. Inhibition of thyroid hormone receptor locally in the retina is a therapeutic strategy for retinal degeneration.

    Science.gov (United States)

    Ma, Hongwei; Yang, Fan; Butler, Michael R; Belcher, Joshua; Redmond, T Michael; Placzek, Andrew T; Scanlan, Thomas S; Ding, Xi-Qin

    2017-08-01

    Thyroid hormone (TH) signaling regulates cell proliferation, differentiation, and metabolism. Recent studies have implicated TH signaling in cone photoreceptor viability. Using mouse models of retinal degeneration, we demonstrated that antithyroid drug treatment and targeting iodothyronine deiodinases (DIOs) to suppress cellular tri-iodothyronine (T3) production or increase T3 degradation preserves cones. In this work, we investigated the effectiveness of inhibition of the TH receptor (TR). Two genes, THRA and THRB , encode TRs; THRB 2 has been associated with cone viability. Using TR antagonists and Thrb2 deletion, we examined the effects of TR inhibition. Systemic and ocular treatment with the TR antagonists NH-3 and 1-850 increased cone density by 30-40% in the Rpe65 -/- mouse model of Leber congenital amaurosis and reduced the number of TUNEL + cells. Cone survival was significantly improved in Rpe65 -/- and Cpfl1 (a model of achromatopsia with Pde6c defect) mice with Thrb2 deletion. Ventral cone density in Cpfl1/Thrb2 -/- and Rpe65 -/- / Thrb2 -/- mice was increased by 1- to 4-fold, compared with age-matched controls. Moreover, the expression levels of TR were significantly higher in the cone-degeneration retinas, suggesting locally elevated TR signaling. This work shows that the effects of antithyroid treatment or targeting DIOs were likely mediated by TRs and that suppressing TR protects cones. Our findings support the view that inhibition of TR locally in the retina is a therapeutic strategy for retinal degeneration management.-Ma, H., Yang, F., Butler, M. R., Belcher, J., Redmond, T. M., Placzek, A. T., Scanlan, T. S., Ding, X.-Q. Inhibition of thyroid hormone receptor locally in the retina is a therapeutic strategy for retinal degeneration. © FASEB.

  13. Pharmacological differences between the D-2 autoreceptor and the D-1 dopamine receptor in rabbit retina

    International Nuclear Information System (INIS)

    Dubocovich, M.L.; Weiner, N.

    1985-01-01

    The effect of dopamine receptor agonists and antagonists was studied on the calcium-dependent release of [ 3 H]dopamine elicited by field stimulation at 3 Hz for a duration of 1 min (20 mA, 2 msec) from the rabbit retina in vitro and on adenylate cyclase activity in homogenates of rabbit retina. The relative order of potency of dopamine receptor agonists to inhibit the stimulation-evoked [ 3 H]dopamine release was pergolide greater than bromocriptine greater than apomorphine greater than LY 141865 greater than N,N-di-n-propyldopamine greater than or equal to dopamine. The relative order of potencies of dopamine receptor antagonists to increase [ 3 H]dopamine release was: S-sulpiride greater than or equal to domperidone greater than or equal to spiroperidol greater than metoclopramide greater than fluphenazine greater than or equal to R-sulpiride. alpha-Flupenthixol (0.01-1 microM) and (+)-butaclamol (0.01-1 microM) did not increase [ 3 H]dopamine overflow when added alone, but they antagonized the concentration-dependent inhibitory effect of apomorphine (0.1-10 microM). These results suggest that the dopamine inhibitory autoreceptor involved in the modulation of dopamine release from the rabbit retina possesses the pharmacological characteristics of a D-2 dopamine receptor. Maximal stimulation by 30 microM dopamine resulted in a 3-fold increase in adenylate cyclase activity with half-maximal stimulation occurring at a concentration of 2.46 microM. Apomorphine and pergolide elicited a partial stimulation of adenylate cyclase activity. However, at low concentrations both compounds were more potent than dopamine

  14. Pharmacological and biochemical characterization of the D-1 dopamine receptor mediating acetylcholine release in rabbit retina

    International Nuclear Information System (INIS)

    Hensler, J.G.; Cotterell, D.J.; Dubocovich, M.L.

    1987-01-01

    Superfusion with dopamine (0.1 microM-10 mM) evokes calcium-dependent [ 3 H]acetylcholine release from rabbit retina labeled in vitro with [ 3 H]choline. This effect is antagonized by the D-1 dopamine receptor antagonist SCH 23390. Activation or blockade of D-2 dopamine, alpha-2 or beta receptors did not stimulate or attenuate the release of [ 3 H]acetylcholine from rabbit retina. Dopamine receptor agonists evoke the release of [ 3 H]acetylcholine with the following order of potency: apomorphine ≤ SKF(R)82526 3 H]acetylcholine: SCH 23390 (IC50 = 1 nM) 3 H]acetylcholine release is characteristic of the D-1 dopamine receptor. These potencies were correlated with the potencies of dopamine receptor agonists and antagonists at the D-1 dopamine receptor in rabbit retina as labeled by [ 3 H]SCH 23390, or as determined by adenylate cyclase activity. [ 3 H]SCH 23390 binding in rabbit retinal membranes was stable, saturable and reversible. Scatchard analysis of [ 3 H]SCH 23390 saturation data revealed a single high affinity binding site (Kd = 0.175 +/- 0.002 nM) with a maximum binding of 482 +/- 12 fmol/mg of protein. The potencies of dopamine receptor agonists to stimulate [ 3 H]acetylcholine release were correlated with their potencies to stimulate adenylate cyclase (r = 0.784, P less than .05, n = 7) and with their affinities at [ 3 H]SCH 23390 binding sites (r = 0.755, P < .05, n = 8)

  15. Distribution of mammalian-like melanopsin in cyclostome retinas exhibiting a different extent of visual functions.

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    Lanfang Sun

    Full Text Available Mammals contain 1 melanopsin (Opn4 gene that is expressed in a subset of retinal ganglion cells to serve as a photopigment involved in non-image-forming vision such as photoentrainment of circadian rhythms. In contrast, most nonmammalian vertebrates possess multiple melanopsins that are distributed in various types of retinal cells; however, their functions remain unclear. We previously found that the lamprey has only 1 type of mammalian-like melanopsin gene, which is similar to that observed in mammals. Here we investigated the molecular properties and localization of melanopsin in the lamprey and other cyclostome hagfish retinas, which contribute to visual functions including image-forming vision and mainly to non-image-forming vision, respectively. We isolated 1 type of mammalian-like melanopsin cDNA from the eyes of each species. We showed that the recombinant lamprey melanopsin was a blue light-sensitive pigment and that both the lamprey and hagfish melanopsins caused light-dependent increases in calcium ion concentration in cultured cells in a manner that was similar to that observed for mammalian melanopsins. We observed that melanopsin was distributed in several types of retinal cells, including horizontal cells and ganglion cells, in the lamprey retina, despite the existence of only 1 melanopsin gene in the lamprey. In contrast, melanopsin was almost specifically distributed to retinal ganglion cells in the hagfish retina. Furthermore, we found that the melanopsin-expressing horizontal cells connected to the rhodopsin-containing short photoreceptor cells in the lamprey. Taken together, our findings suggest that in cyclostomes, the global distribution of melanopsin in retinal cells might not be related to the melanopsin gene number but to the extent of retinal contribution to visual function.

  16. Chloride currents in cones modify feedback from horizontal cells to cones in goldfish retina

    Science.gov (United States)

    Endeman, Duco; Fahrenfort, Iris; Sjoerdsma, Trijntje; Steijaert, Marvin; ten Eikelder, Huub; Kamermans, Maarten

    2012-01-01

    In neuronal systems, excitation and inhibition must be well balanced to ensure reliable information transfer. The cone/horizontal cell (HC) interaction in the retina is an example of this. Because natural scenes encompass an enormous intensity range both in temporal and spatial domains, the balance between excitation and inhibition in the outer retina needs to be adaptable. How this is achieved is unknown. Using electrophysiological techniques in the isolated retina of the goldfish, it was found that opening Ca2+-dependent Cl− channels in recorded cones reduced the size of feedback responses measured in both cones and HCs. Furthermore, we show that cones express Cl− channels that are gated by GABA released from HCs. Similar to activation of ICl(Ca), opening of these GABA-gated Cl− channels reduced the size of light-induced feedback responses both in cones and HCs. Conversely, application of picrotoxin, a blocker of GABAA and GABAC receptors, had the opposite effect. In addition, reducing GABA release from HCs by blocking GABA transporters also led to an increase in the size of feedback. Because the independent manipulation of Ca2+-dependent Cl− currents in individual cones yielded results comparable to bath-applied GABA, it was concluded that activation of either Cl− current by itself is sufficient to reduce the size of HC feedback. However, additional effects of GABA on outer retinal processing cannot be excluded. These results can be accounted for by an ephaptic feedback model in which a cone Cl− current shunts the current flow in the synaptic cleft. The Ca2+-dependent Cl− current might be essential to set the initial balance between the feedforward and the feedback signals active in the cone HC synapse. It prevents that strong feedback from HCs to cones flood the cone with Ca2+. Modulation of the feedback strength by GABA might play a role during light/dark adaptation, adjusting the amount of negative feedback to the signal to noise ratio of the

  17. Characterization of Pax2 expression in the goldfish optic nerve head during retina regeneration.

    Directory of Open Access Journals (Sweden)

    Marta Parrilla

    Full Text Available The Pax2 transcription factor plays a crucial role in axon-guidance and astrocyte differentiation in the optic nerve head (ONH during vertebrate visual system development. However, little is known about its function during regeneration. The fish visual system is in continuous growth and can regenerate. Müller cells and astrocytes of the retina and ONH play an important role in these processes. We demonstrate that pax2a in goldfish is highly conserved and at least two pax2a transcripts are expressed in the optic nerve. Moreover, we show two different astrocyte populations in goldfish: Pax2(+ astrocytes located in the ONH and S100(+ astrocytes distributed throughout the retina and the ONH. After peripheral growth zone (PGZ cryolesion, both Pax2(+ and S100(+ astrocytes have different responses. At 7 days after injury the number of Pax2(+ cells is reduced and coincides with the absence of young axons. In contrast, there is an increase of S100(+ astrocytes in the retina surrounding the ONH and S100(+ processes in the ONH. At 15 days post injury, the PGZ starts to regenerate and the number of S100(+ astrocytes increases in this region. Moreover, the regenerating axons reach the ONH and the pax2a gene expression levels and the number of Pax2(+ cells increase. At the same time, S100(+/GFAP(+/GS(+ astrocytes located in the posterior ONH react strongly. In the course of the regeneration, Müller cell vitreal processes surrounding the ONH are primarily disorganized and later increase in number. During the whole regenerative process we detect a source of Pax2(+/PCNA(+ astrocytes surrounding the posterior ONH. We demonstrate that pax2a expression and the Pax2(+ astrocyte population in the ONH are modified during the PGZ regeneration, suggesting that they could play an important role in this process.

  18. On the distributive patterns of ATPase activity and its functional significance in retinae of certain birds.

    Science.gov (United States)

    Tewari, H B; Tyagi, H R

    1977-01-01

    The present study incorporates the details of distribution of adenosine triphosphatase amongst the various constituents of retinae of Passer, Psittacula, Streptopelia and Athene. The outer segments in all the cases are intensely positive for the enzyme. This is the part where the light strikes first and initiates the visual processes. The nuclear layers are also positive for the enzyme activity. It is interesting to note that inner plexiform layers show clear-out demarcations of various sub-synaptic layers in all the birds except Psittacula. The ganglion cells and optic nerve fibres are also positive for the enzyme.

  19. Msx1 is expressed in retina endothelial cells at artery branching sites

    Directory of Open Access Journals (Sweden)

    Miguel Lopes

    2012-02-01

    Msx1 and Msx2 encode homeodomain transcription factors that play a role in several embryonic developmental processes. Previously, we have shown that in the adult mouse, Msx1lacZ is expressed in vascular smooth muscle cells (VSMCs and pericytes, and that Msx2lacZ is also expressed in VSMCs as well as in a few endothelial cells (ECs. The mouse retina and choroid are two highly vascularized tissues. Vessel alterations in the retina are associated with several human diseases and the retina has been intensely used for angiogenesis studies, whereas the choroid has been much less investigated. Using the Msx1lacZ and Msx2lacZ reporter alleles, we observed that Msx2 is not expressed in the eye vascular tree in contrast to Msx1, for which we establish the spatial and temporal expression pattern in these tissues. In the retina, expression of Msx1 takes place from P3, and by P10, it becomes confined to a subpopulation of ECs at branching points of superficial arterioles. These branching sites are characterized by a subpopulation of mural cells that also show specific expression programs. Specific Msx gene inactivation in the endothelium, using Msx1 and Msx2 conditional mutant alleles together with a Tie2-Cre transgene, did not lead to conspicuous structural defects in the retinal vascular network. Expression of Msx1 at branching sites might therefore be linked to vessel physiology. The retinal blood flow is autonomously regulated and perfusion of capillaries has been proposed to depend on arteriolar precapillary structures that might be the sites for Msx1 expression. On the other hand, branching sites are subject to shear stress that might induce Msx1 expression. In the choroid vascular layer Msx1lacZ is expressed more broadly and dynamically. At birth Msx1lacZ expression takes place in the endothelium but at P21 its expression has shifted towards the mural layer. We discuss the possible functions of Msx1 in the eye vasculature.

  20. Msx1 is expressed in retina endothelial cells at artery branching sites.

    Science.gov (United States)

    Lopes, Miguel; Goupille, Olivier; Saint Cloment, Cécile; Robert, Benoît

    2012-04-15

    Msx1 and Msx2 encode homeodomain transcription factors that play a role in several embryonic developmental processes. Previously, we have shown that in the adult mouse, Msx1(lacZ) is expressed in vascular smooth muscle cells (VSMCs) and pericytes, and that Msx2(lacZ) is also expressed in VSMCs as well as in a few endothelial cells (ECs). The mouse retina and choroid are two highly vascularized tissues. Vessel alterations in the retina are associated with several human diseases and the retina has been intensely used for angiogenesis studies, whereas the choroid has been much less investigated. Using the Msx1(lacZ) and Msx2(lacZ) reporter alleles, we observed that Msx2 is not expressed in the eye vascular tree in contrast to Msx1, for which we establish the spatial and temporal expression pattern in these tissues. In the retina, expression of Msx1 takes place from P3, and by P10, it becomes confined to a subpopulation of ECs at branching points of superficial arterioles. These branching sites are characterized by a subpopulation of mural cells that also show specific expression programs. Specific Msx gene inactivation in the endothelium, using Msx1 and Msx2 conditional mutant alleles together with a Tie2-Cre transgene, did not lead to conspicuous structural defects in the retinal vascular network. Expression of Msx1 at branching sites might therefore be linked to vessel physiology. The retinal blood flow is autonomously regulated and perfusion of capillaries has been proposed to depend on arteriolar precapillary structures that might be the sites for Msx1 expression. On the other hand, branching sites are subject to shear stress that might induce Msx1 expression. In the choroid vascular layer Msx1(lacZ) is expressed more broadly and dynamically. At birth Msx1(lacZ) expression takes place in the endothelium but at P21 its expression has shifted towards the mural layer. We discuss the possible functions of Msx1 in the eye vasculature.

  1. Synaptic Mechanisms Generating Orientation Selectivity in the ON Pathway of the Rabbit Retina.

    Science.gov (United States)

    Venkataramani, Sowmya; Taylor, W Rowland

    2016-03-16

    Neurons that signal the orientation of edges within the visual field have been widely studied in primary visual cortex. Much less is known about the mechanisms of orientation selectivity that arise earlier in the visual stream. Here we examine the synaptic and morphological properties of a subtype of orientation-selective ganglion cell in the rabbit retina. The receptive field has an excitatory ON center, flanked by excitatory OFF regions, a structure similar to simple cell receptive fields in primary visual cortex. Examination of the light-evoked postsynaptic currents in these ON-type orientation-selective ganglion cells (ON-OSGCs) reveals that synaptic input is mediated almost exclusively through the ON pathway. Orientation selectivity is generated by larger excitation for preferred relative to orthogonal stimuli, and conversely larger inhibition for orthogonal relative to preferred stimuli. Excitatory orientation selectivity arises in part from the morphology of the dendritic arbors. Blocking GABAA receptors reduces orientation selectivity of the inhibitory synaptic inputs and the spiking responses. Negative contrast stimuli in the flanking regions produce orientation-selective excitation in part by disinhibition of a tonic NMDA receptor-mediated input arising from ON bipolar cells. Comparison with earlier studies of OFF-type OSGCs indicates that diverse synaptic circuits have evolved in the retina to detect the orientation of edges in the visual input. A core goal for visual neuroscientists is to understand how neural circuits at each stage of the visual system extract and encode features from the visual scene. This study documents a novel type of orientation-selective ganglion cell in the retina and shows that the receptive field structure is remarkably similar to that of simple cells in primary visual cortex. However, the data indicate that, unlike in the cortex, orientation selectivity in the retina depends on the activity of inhibitory interneurons. The

  2. Quantitative Assessment of Microstructural Changes of the Retina in Infants With Congenital Zika Syndrome.

    Science.gov (United States)

    Aleman, Tomas S; Ventura, Camila V; Cavalcanti, Milena M; Serrano, Leona W; Traband, Anastasia; Nti, Akosua A; Gois, Adriana L; Bravo-Filho, Vasco; Martins, Thayze T; Nichols, Charles W; Maia, Mauricio; Belfort, Rubens

    2017-10-01

    A better pathophysiologic understanding of the neurodevelopmental abnormalities observed in neonates exposed in utero to Zika virus (ZIKV) is needed to develop treatments. The retina as an extension of the diencephalon accessible to in vivo microcopy with spectral-domain optical coherence tomography (SD-OCT) can provide an insight into the pathophysiology of congenital Zika syndrome (CZS). To quantify the microstructural changes of the retina in CZS and compare these changes with those of cobalamin C (cblC) deficiency, a disease with potential retinal maldevelopment. This case series included 8 infants with CZS and 8 individuals with cblC deficiency. All patients underwent ophthalmologic evaluation at 2 university teaching hospitals and SD-OCT imaging in at least 1 eye. Patients with cblC deficiency were homozygous or compound heterozygotes for mutations in the methylmalonic aciduria and homocystinuria type C (MMACHC) gene. Data were collected from January 1 to March 17, 2016, for patients with CZS and from May 4, 2015, to April 23, 2016, for patients with cblC deficiency. The SD-OCT cross-sections were segmented using automatic segmentation algorithms embedded in the SD-OCT systems. Each retinal layer thickness was measured at critical eccentricities using the position of the signal peaks and troughs on longitudinal reflectivity profiles. Eight infants with CZS (5 girls and 3 boys; age range, 3-5 months) and 8 patients with cblC deficiency (3 girls and 5 boys; age range, 4 months to 15 years) were included in the analysis. All 8 patients with CZS had foveal abnormalities in the analyzed eyes (8 eyes), including discontinuities of the ellipsoid zone, thinning of the central retina with increased backscatter, and severe structural disorganization, with 3 eyes showing macular pseudocolobomas. Pericentral retina with normal lamination showed a thinned (<30% of normal thickness) ganglion cell layer (GCL) that colocalized in 7 of 8 eyes with a normal photoreceptor layer

  3. Isolation of progenitor cells from GFP-transgenic pigs and transplantation to the retina of allorecipients

    DEFF Research Database (Denmark)

    Klassen, Henry; Warfvinge, Karin; Schwartz, Philip H

    2008-01-01

    to survival as allografts and integrate into the host retinal architecture, we isolated donor cells from fetal green fluorescent protein (GFP)-transgenic pigs. Cultures were propagated from the brain, retina, and corneo-scleral limbus. GFP expression rapidly increased with time in culture, although lower...... in conjunction with photoreceptor markers and glial fibrillary acid protein (GFAP), thus suggesting downregulation of GFP during differentiation. Following transplantation, GFP expression allowed histological visualization of integrated cells and extension of fine processes to adjacent plexiform layers. GFP...

  4. Scotopic electrophysiology of the retina during transient hyperglycemia in type 2 diabetes

    DEFF Research Database (Denmark)

    Holfort, Stig Kraglund; Klemp, Kristian; Kofoed, Peter Kristian

    2010-01-01

    PURPOSE: To examine dark-adapted retinal function in subjects with type 2 diabetes during transient hyperglycemia. METHODS: Twenty-four subjects with type 2 diabetes and minimal diabetic retinopathy were randomized to an oral glucose tolerance test (OGTT) or a fasting regimen. One study eye...... by hyperglycemia. The scotopic ffERG amplitudes rose and fell in phase with the glycemia. Implicit times did not change with the rise and fall in glycemia. CONCLUSIONS: The change in scotopic signaling amplitude in the outer and middle layers of retina in subjects with diabetes was proportional to the change...... in capillary glucose. Cone amplitude was not influenced by hyperglycemia in this study....

  5. Quantum photoelectron effects in the eye retina and development of colour vision theory

    International Nuclear Information System (INIS)

    Kremkov, M.V.

    2011-01-01

    The quantum semiconductor mechanism of the colour vision of mans is created. The mechanism is based on quantum effects under influence of light waves exciting valence electrons in different microelement's atoms (Zn, Cu, Fe, Co, P, Br, Se, et al.) that are presented in the photoreceptor's cells of the eye retina (columns and retorts) with the quasi-periodical disks structure. The microelement concentrations correspond to the impurity atom amount in semiconductors, and the photoelectron's current passes out its signal to the vision nerve. The mechanism explains existence of the man colour-blindness, degradation of the vision sensitivity with the man's age and other peculiarities of the colour vision. (authors)

  6. Molecular Characterization of Notch1 Positive Progenitor Cells in the Developing Retina.

    Directory of Open Access Journals (Sweden)

    Galina Dvoriantchikova

    Full Text Available The oscillatory expression of Notch signaling in neural progenitors suggests that both repressors and activators of neural fate specification are expressed in the same progenitors. Since Notch1 regulates photoreceptor differentiation and contributes (together with Notch3 to ganglion cell fate specification, we hypothesized that genes encoding photoreceptor and ganglion cell fate activators would be highly expressed in Notch1 receptor-bearing (Notch1+ progenitors, directing these cells to differentiate into photoreceptors or into ganglion cells when Notch1 activity is diminished. To identify these genes, we used microarray analysis to study expression profiles of whole retinas and isolated from them Notch1+ cells at embryonic day 14 (E14 and postnatal day 0 (P0. To isolate Notch1+ cells, we utilized immunomagnetic cell separation. We also used Notch3 knockout (Notch3KO animals to evaluate the contribution of Notch3 signaling in ganglion cell differentiation. Hierarchical clustering of 6,301 differentially expressed genes showed that Notch1+ cells grouped near the same developmental stage retina cluster. At E14, we found higher expression of repressors (Notch1, Hes5 and activators (Dll3, Atoh7, Otx2 of neuronal differentiation in Notch1+ cells compared to whole retinal cell populations. At P0, Notch1, Hes5, and Dll1 expression was significantly higher in Notch1+ cells than in whole retinas. Otx2 expression was more than thirty times higher than Atoh7 expression in Notch1+ cells at P0. We also observed that retinas of wild type animals had only 14% (P < 0.05 more ganglion cells compared to Notch3KO mice. Since this number is relatively small and Notch1 has been shown to contribute to ganglion cell fate specification, we suggested that Notch1 signaling may play a more significant role in RGC development than the Notch3 signaling cascade. Finally, our findings suggest that Notch1+ progenitors--since they heavily express both pro-ganglion cell (Atoh7

  7. Distribution of light in the human retina under natural viewing conditions

    Science.gov (United States)

    Gibert, Jorge C.

    Age-related macular degeneration (AMD) is the leading cause of blindness inAmerica. The fact that AMD wreaks most of the damage in the center of the retina raises the question of whether light, integrated over long periods, is more concentrated in the macula. A method, based on eye-tracking, was developed to measure the distribution of light in the retina under natural viewing conditions. The hypothesis was that integrated over time, retinal illumination peaked in the macula. Additionally a possible relationship between age and retinal illumination was investigated. The eye tracker superimposed the subject's gaze position on a video recorded by a scene camera. Five informed subjects were employed in feasibility tests, and 58 naive subjects participated in 5 phases. In phase 1 the subjects viewed a gray-scale image. In phase 2, they observed a sequence of photographic images. In phase 3 they viewed a video. In phase 4, they worked on a computer; in phase 5, the subjects walked around freely. The informed subjects were instructed to gaze at bright objects in the field of view and then at dark objects. Naive subjects were allowed to gaze freely for all phases. Using the subject's gaze coordinates, and the video provided by the scene camera, the cumulative light distribution on the retina was calculated for ˜15° around the fovea. As expected for control subjects, cumulative retinal light distributions peaked and dipped in the fovea when they gazed at bright or dark objects respectively. The light distribution maps obtained from the naive subjects presented a tendency to peak in the macula for phases 1, 2, and 3, a consistent tendency in phase 4 and a variable tendency in phase 5. The feasibility of using an eye-tracker system to measure the distribution of light in the retina was demonstrated, thus helping to understand the role played by light exposure in the etiology of AMD. Results showed that a tendency for light to peak in the macula is a characteristic of some

  8. Nervus terminalis projection to the retina in the 'four-eyed' fish, Anableps anableps.

    Science.gov (United States)

    Meyer, D L; Malz, C R; Jadhao, A G

    1996-08-02

    The eye of the surface dwelling 'four-eyed' fish, Anableps possesses an aquatic and an aerial optical system. The aerial system is strongly hyperopic when the animal dives, i.e. during mating, and the dorsal pupil is submerged. We studied the retino-petal nervus terminals projection to the aerial and to the aquatic retina by Phe-Met-Arg-Phe-NH2 (FMRF) immunocytochemistry and found both to be equally innervated. This finding sheds doubt on the proposed functional significance of this projection for reproductive behaviour.

  9. Onda de calcio intercelular en epitelio pigmentario de la retina humano: mediciones directas de calcio reticular.

    OpenAIRE

    González Zamora, Jorge

    2017-01-01

    Hasta el más simple órgano de la visión se compone de al menos dos tipos celulares: los fotoreceptores y las células pigmentadas, demostrando la vital importancia de su interacción. En vertebrados, el epitelio pigmentario de la retina (EPR) se localiza entre los segmentos externos de los fotoreceptores y los capilares de la coroides y desde esta posición estratégica realiza una gran variedad de funciones: absorbe luz, actúa de barrera hemato-retiniana, secreta numerosos factores, recicla el f...

  10. Role of the nucleolus in neurodegenerative diseases with particular reference to the retina: a review.

    Science.gov (United States)

    Sia, Paul I; Wood, John Pm; Chidlow, Glyn; Sharma, Shiwani; Craig, Jamie; Casson, Robert J

    2016-04-01

    The nucleolus has emerged as a key regulator of cellular growth and the response to stress, in addition to its traditionally understood function in ribosome biogenesis. The association between nucleolar function and neurodegenerative disease is increasingly being explored. There is also recent evidence indicating that the nucleolus may well be crucial in the development of the eye. In this present review, the role of the nucleolus in retinal development as well as in neurodegeneration with an emphasis on the retina is discussed. © 2015 Royal Australian and New Zealand College of Ophthalmologists.

  11. Artificial Retina Project: Final Report for CRADA ORNL 01-0625

    Energy Technology Data Exchange (ETDEWEB)

    Greenbaum, E; Little, J [Second Sight Medical Products

    2011-09-01

    The U.S. Department of Energy’s Artificial Retina Project is a collaborative, multi-institutional effort to develop an implantable microelectronic retinal prosthesis that restores useful vision to people blinded by retinal diseases. The ultimate goal of the project is to restore reading ability, facial recognition, and unaided mobility in people with retinitis pigmentosa and age-related macular degeneration. The project taps into the unique research technologies and resources developed at DOE national laboratories to surmount the many technical challenges involved with developing a safe, effective, and durable product. The research team includes six DOE national laboratories, four universities, and private industry.

  12. Hereditary retinal eye diseases in childhood and youth affecting the central retina

    Directory of Open Access Journals (Sweden)

    Martin M Nentwich

    2013-01-01

    Classic examinations for patients suffering from hereditary retinal dystrophies of the central retina are funduscopy - also using red-free light - visual-field tests, electrophysiologic tests as electro-retinogram [ERG] and multifocal ERG and tests evaluating color vision. Recently, new imaging modalities have been introduced into the clinical practice. The significance of these new methods such as high-resolution spectral-domain optic coherence tomography [SD-OCT] and fundus autofluorescence will be discussed as well as "next generation sequencing" as a new method for the analysis of genetic mutations in a larger number of patients.

  13. Extracellular Matrix components regulate cellular polarity and tissue structure in the developing and mature Retina

    Directory of Open Access Journals (Sweden)

    Shweta Varshney

    2015-01-01

    Full Text Available While genetic networks and other intrinsic mechanisms regulate much of retinal development, interactions with the extracellular environment shape these networks and modify their output. The present review has focused on the role of one family of extracellular matrix molecules and their signaling pathways in retinal development. In addition to their effects on the developing retina, laminins play a role in maintaining Müller cell polarity and compartmentalization, thereby contributing to retinal homeostasis. This article which is intended for the clinical audience, reviews the fundamentals of retinal development, extracellular matrix organization and the role of laminins in retinal development. The role of laminin in cortical development is also briefly discussed.

  14. In Vivo Imaging of Microglia Turnover in the Mouse Retina After Ionizing Radiation and Dexamethasone Treatment

    DEFF Research Database (Denmark)

    Alt, C.; Runnels, J. M.; Mortensen, L. J.

    2014-01-01

    irradiation with a confocal scanning laser ophthalmoscope that we custom-built specifically for multicolor imaging of the murine retina. RESULTS. Ionizing radiation resulted in loss of 75% of the resident retinal microglia population after 70 days. Recruitment of BMDCs was delayed with respect...... dexamethasone preserves resident microglia and minimizes recruitment of BMDCs after ionizing radiation exposure and BMT.......PURPOSE. Gamma irradiation and bone marrow transplantation (BMT) are established clinical procedures for the treatment of hematologic malignancies. The radiation targets cells in the bone marrow, but injury to other tissues, including the central nervous system (CNS), have been reported. Here, we...

  15. Effect of intravitreal injection of bevacizumab-chitosan nanoparticles on retina of diabetic rats

    Directory of Open Access Journals (Sweden)

    Yan Lu

    2014-02-01

    Full Text Available AIM:To investigate the effects of intravitreal injection of bevacizumab-chitosan nanoparticles on pathological morphology of retina and the expression of vascular endothelial growth factor (VEGF protein and VEGF mRNA in the retina of diabetic rats.METHODS: Seventy-two 3-month aged diabetic rats were randomly divided into 3 groups, each containing 24 animals and 48 eyes. Both eyes of the rats in group A were injected into the vitreous at the pars plana with 3μL of physiological saline, while in groups B and C were injected with 3μL (75μg of bevacizumab and 3μL of bevacizumab-chitosan nanoparticles (containing 75μg of bevacizumab, respectively. Immunohistochemistry was used to assess retinal angiogenesis, real-time PCR assay was used to analyse the expression of VEGF mRNA, and light microscopy was used to evaluate the morphology of retinal capillaries.RESULTS:Real-time PCR assay revealed that the VEGF mRNA expression in the retina before injection was similar to 1 week after injection in group A (P>0.05, while theVEGF mRNA expression before injection significantly differed from those 4 and 8 weeks after injection (P<0.05. Retinal expression of VEGF protein and VEGF mRNA was inhibited 1 week and 4 weeks after injection (P<0.05 in group B, and the expression of VEGF protein and VEGF mRNA was obviously inhibited until 8 weeks after injection (P<0.05 in group C. Using multiple comparisons among group A, group B, and group C, the VEGF expression before injection was higher than at 1, 4 and 8 weeks after injection (P<0.05. The amount of VEGF expression was higher 8 weeks after injection than 1 week or 4 weeks after injection, and also higher 1 week after injection compared with 4 weeks after injection (P<0.05. No toxic effect on SD rats was observed with bevacizumab-chitosan nanoparticles injection alone.CONCLUSION: The results offer a new approach for inhibiting angiogenesis of diabetic retinopathy and indicate that the intravitreal injection of

  16. Rod and cone interactions in the retina [version 1; referees: 4 approved

    Directory of Open Access Journals (Sweden)

    Gordon Fain

    2018-05-01

    Full Text Available We have long known that rod and cone signals interact within the retina and can even contribute to color vision, but the extent of these influences has remained unclear. New results with more powerful methods of RNA expression profiling, specific cell labeling, and single-cell recording have provided greater clarity and are showing that rod and cone signals can mix at virtually every level of signal processing. These interactions influence the integration of retinal signals and make an important contribution to visual perception.

  17. RETINOBASE: a web database, data mining and analysis platform for gene expression data on retina

    Directory of Open Access Journals (Sweden)

    Léveillard Thierry

    2008-05-01

    Full Text Available Abstract Background The retina is a multi-layered sensory tissue that lines the back of the eye and acts at the interface of input light and visual perception. Its main function is to capture photons and convert them into electrical impulses that travel along the optic nerve to the brain where they are turned into images. It consists of neurons, nourishing blood vessels and different cell types, of which neural cells predominate. Defects in any of these cells can lead to a variety of retinal diseases, including age-related macular degeneration, retinitis pigmentosa, Leber congenital amaurosis and glaucoma. Recent progress in genomics and microarray technology provides extensive opportunities to examine alterations in retinal gene expression profiles during development and diseases. However, there is no specific database that deals with retinal gene expression profiling. In this context we have built RETINOBASE, a dedicated microarray database for retina. Description RETINOBASE is a microarray relational database, analysis and visualization system that allows simple yet powerful queries to retrieve information about gene expression in retina. It provides access to gene expression meta-data and offers significant insights into gene networks in retina, resulting in better hypothesis framing for biological problems that can subsequently be tested in the laboratory. Public and proprietary data are automatically analyzed with 3 distinct methods, RMA, dChip and MAS5, then clustered using 2 different K-means and 1 mixture models method. Thus, RETINOBASE provides a framework to compare these methods and to optimize the retinal data analysis. RETINOBASE has three different modules, "Gene Information", "Raw Data System Analysis" and "Fold change system Analysis" that are interconnected in a relational schema, allowing efficient retrieval and cross comparison of data. Currently, RETINOBASE contains datasets from 28 different microarray experiments performed

  18. Amyloid precursor protein is required for normal function of the rod and cone pathways in the mouse retina.

    Directory of Open Access Journals (Sweden)

    Tracy Ho

    Full Text Available Amyloid precursor protein (APP is a transmembrane glycoprotein frequently studied for its role in Alzheimer's disease. Our recent study in APP knockout (KO mice identified an important role for APP in modulating normal neuronal development in the retina. However the role APP plays in the adult retina and whether it is required for vision is unknown. In this study we evaluated the role of APP in retinal function and morphology comparing adult wildtype (WT and APP-KO mice. APP was expressed on neuronal cells of the inner retina, including horizontal, cone bipolar, amacrine and ganglion cells in WT mice. The function of the retina was assessed using the electroretinogram and although the rod photoreceptor responses were similar in APP-KO and WT mice, the post-photoreceptor, inner retinal responses of both the rod and cone pathways were reduced in APP-KO mice. These changes in inner retinal function did not translate to a substantial change in visual acuity as assessed using the optokinetic response or to changes in the gross cellular structure of the retina. These findings indicate that APP is not required for basic visual function, but that it is involved in modulating inner retinal circuitry.

  19. Assessment of apoptosis and oxidative stress in retina tissue of rats with diabetic retinopathy after grape polyphenols intervention

    Institute of Scientific and Technical Information of China (English)

    Sheng-Li Zhang

    2016-01-01

    Objective:To study the effect of grape polyphenols intervention on apoptosis and oxidative stress in retina tissue of rats with diabetic retinopathy (DR).Methods: SPF male SD rats were selected as experimental animals and divided into control group, diabetes group and grape polyphenols group, intraperitoneal injection of streptozotocin was adopted to establish diabetic rat models, and grape polyphenols group received intragastric administration of grape polyphenols. 60 d after model establishment, the rats were executed, and the retina tissue was collected to determine apoptosis molecules and oxidative stress indexes.Results:Bax, Caspase-3, c-fos, c-jun, ROS, MDA, 8-OHdG, PARP, Cyclophilin D, Nrf-2, ARE, ERK and PI3K content in retina tissue of diabetes group were significantly higher than those of control group while Bcl-2, CAT, SOD, GSH-Px, HO-1 and NQO1 content were significantly lower than those of control group; Bax, Caspase-3, c-fos, c-jun, ROS, MDA, 8-OHdG, PARP and Cyclophilin D content in retina tissue of grape polyphenols group were significantly lower than those of diabetes group while Bcl-2, CAT, SOD, GSH-Px, HO-1, NQO1, Nrf-2, ARE, ERK and PI3K content were significantly higher those of diabetes group.Conclusions:Grape polyphenols intervention can relieve the apoptosis and oxidative stress in retina tissue of rats with diabetic retinopathy.

  20. Comparative immunolocalization of the plasma membrane calcium pump and calbindin D28K in chicken retina during embryonic development

    Directory of Open Access Journals (Sweden)

    N. Tolosa de Talamoni

    2010-05-01

    Full Text Available The immunolocalization of the plasma membrane calcium pump (PMCA was studied in 4-week-old chick retina in comparison with calbindin D28K (CaBP immunostaining. We have demonstrated that the monoclonal anti-PMCA antibody 5F10 from human erythrocyte plasma membrane crossreacts with a Ca2+ pump epitope of the cells from the neural retina. The immunolocalization of both proteins was also studied during the embryonic development of the chicken retina. At age 4.5 days, the cells of the retina were faintly immunoreactive to PMCA and CaBP antibodies, but the lack of cellular aggregation and differentiation did not allow discrimination between the two proteins. A clear difference in the localization was seen from the tenth day of development through post-hatching with slight variation. PMCA localized mainly in the outer and inner plexiform layers, in some cells in the ganglion layer, in the nerve fiber layer and slightly in the photoreceptor cells. CaBP was intensely stained in cones, cone pedicles and some amacrine cells. The number of CaBP positive amacrine cells declined after hatching. A few ganglion cells and several nerve fibers were CaBP 333 immunoreactive. The role of these proteins in the early stages of retinal development is unknown, but the results suggest that Ca2+ homeostasis in the retina is well regulated, probably to avoid excessive accumulation of Ca2+, which often leads to neurodegeneration.

  1. Avaliação da onda b do eletrorretinograma na Athene cunicularia Evaluation of the b-wave electroretinogram in Athene cunicularia

    Directory of Open Access Journals (Sweden)

    Márcio Penha Morterá Rodrigues

    2008-12-01

    Full Text Available OBJETIVO: Avaliar a onda b do eletrorretinograma da coruja buraqueira (Athene cunicularia, diferenciando a resposta elétrica retiniana em ambiente fotópico e escotópico. MÉTODOS: Foi realizado estudo observacional transversal, com o registro do eletrorretinograma full field de quatorze olhos, sendo sete estimulados em ambiente fotópico e sete em ambiente escotópico sob estímulo com luz branca seguindo protocolo da ISCEV. RESULTADOS: As respostas elétricas da retina da espécie estudada para o espectro de luz aplicado mostraram-se presentes em ambos ambientes, não havendo diferença estatisticamente significativa da resposta elétrica da retina da Athene cunicularia quando estimulada com luz branca, tanto em ambiente escotópico quanto fotópico. CONCLUSÃO: Os dados nos permitem, portanto, inferir que a percepção pela Athene cunicularia da cor branca é a mesma, no claro e no escuro, o que pode ser responsável pela capacidade adaptativa da espécie no seu habitat natural.PURPOSE: To evaluate b-wave of the electroretinogram of the burrowing owl (Athene cunicularia, differentiating the retinal electric reply in photopic and scotopic environment. METHODS: Transversal observational study was carried through, with the register of the full field electroretinogram of fourteen eyes; seven were stimulated in photopic environment and seven in scotopic environment using with white light according to the ISCEV protocol. RESULTS: The electrical responses of the retina of the species studied showed no statistically significant difference for the applied spectrum of white light in both scotopic photopic environments. CONCLUSION: The data allow us, therefore, to infer that the perception of the Athene cunicularia of the white color is the same one, in clear and dark environments, what it can be responsible for the adaptive capacity of the species in their natural habitat.

  2. Registro de actividad eléctrica en la retina de una rata albina empleando una matriz de microelectrodos

    Directory of Open Access Journals (Sweden)

    Edwin Alexander Cerquera

    2015-09-01

    Full Text Available Las matrices de microelectrodos son dispositivos que permiten la detección de potenciales de acción o espigas en poblaciones de células excitables, ofreciendo varias aplicaciones en el campo de las neurociencias y la biología. Este trabajo muestra un protocolo para el registro de espigas en una población de células ganglionares retinales empleando una matriz de microelectrodos. La retina de una rata albina fue extraída y preparada para ser estimulada in vitro con luz led blanca, con el fin de registrar sus espigas evocadas ante estos estímulos. Cada microelectrodo puede registrar espigas de más de una célula ganglionar, razón por la cual se determinó a qué célula pertenece cada espiga aplicando un procedimiento conocido como “clasificación de espigas”. El trabajo permitió obtener el registro de un periodo de estimulación y otro de no estimulación, con el fin de representar los potenciales de acción evocados con luz y los espontáneos. Los registros fueron almacenados para visualizar las espigas de las células ganglionares y poder aplicar la herramienta de clasificación de espigas. De este modo, se almacenan los instantes de tiempo en los cuales cada célula ganglionar registrada generó potenciales de acción. Este trabajo conllevó al establecimiento de un protocolo de experimentación básico enfocado al uso de matrices MEA en el laboratorio de adquisición de potenciales extracelulares de la Universidad Antonio Nariño Sede Bogotá, no sólo para caracterizar los potenciales de acción de células ganglionares retinales, sino también para otro tipo de células que puedan ser estudiadas empleando matrices de microelectrodos.

  3. Bipolar Cell-Photoreceptor Connectivity in the Zebrafish (Danio rerio) Retina

    Science.gov (United States)

    Li, Yong N.; Tsujimura, Taro; Kawamura, Shoji; Dowling, John E.

    2013-01-01

    Bipolar cells convey luminance, spatial and color information from photoreceptors to amacrine and ganglion cells. We studied the photoreceptor connectivity of 321 bipolar cells in the adult zebrafish retina. 1,1'-Dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) was inserted into whole-mounted transgenic zebrafish retinas to label bipolar cells. The photoreceptors that connect to these DiI-labeled cells were identified by transgenic fluorescence or their positions relative to the fluorescent cones, as cones are arranged in a highly-ordered mosaic: rows of alternating blue- (B) and ultraviolet-sensitive (UV) single cones alternate with rows of red- (R) and green-sensitive (G) double cones. Rod terminals intersperse among cone terminals. As many as 18 connectivity subtypes were observed, 9 of which – G, GBUV, RG, RGB, RGBUV, RGRod, RGBRod, RGBUVRod and RRod bipolar cells – accounted for 96% of the population. Based on their axon terminal stratification, these bipolar cells could be further sub-divided into ON, OFF, and ON-OFF cells. The dendritic spread size, soma depth and size, and photoreceptor connections of the 308 bipolar cells within the 9 common connectivity subtypes were determined, and their dendritic tree morphologies and axonal stratification patterns compared. We found that bipolar cells with the same axonal stratification patterns could have heterogeneous photoreceptor connectivity whereas bipolar cells with the same dendritic tree morphology usually had the same photoreceptor connectivity, although their axons might stratify on different levels. PMID:22907678

  4. Insulin stimulates choline acetyltransferase activity in cultured embryonic chicken retina neurons

    International Nuclear Information System (INIS)

    Kyriakis, J.M.; Hausman, R.E.; Peterson, S.W.

    1987-01-01

    The effect of insulin on the appearance of the enzyme choline acetyltransferase in embryonic chicken retina neurons cultured in defined medium was studied. In the presence of a minimal level of insulin (1 ng/ml), ChoAcT activity increased with time in culture. A correspondence between the insulin concentration in the defined medium (1-100 ng/ml) and both the rate of increase and maximum attained level of ChoAcT activity was observed. Maximal ChoAcT activity was 2- to 3-fold greater in cells cultured in the presence of 100 ng of insulin per ml than in cells cultured in the presence of 1 ng of insulin per ml. To elicit maximum ChoAcT activity, insulin at 100 ng/ml was required in the medium for only the first 4 days of the culture period, at which time insulin could be reduced to maintenance levels (10 ng/ml) without affecting ChoAcT activity. Insulin binding assays performed during a 7-day culture period revealed that irrespective of the 125 I-insulin concentration in the medium during culture, cell-surface insulin receptors decreased by ≅ 90% between 4 and 7 days in culture. This decrease in insulin binding corresponded to the observed decrease in the sensitivity of ChoAcT activity to insulin. The findings suggest that insulin plays a role in mediating cholinergic differentiation in the embryonic chicken retina

  5. [Evaluation of fundus autofluorescence in hereditary retinal diseases using Heidelberg Retina Angiograph2].

    Science.gov (United States)

    Côco, Monique; Baba, Natalia Tamie; Sallum, Juliana Maria Ferraz

    2007-01-01

    To define characteristics of the fundus autofluorescence examination, verifying usefulness in the diagnosis and care of hereditary retinal diseases. 28 patients, adults, divided equally into four groups with diagnoses of Stargardt macular dystrophy, cone dystrophy, retinitis pigmentosa and healthy volunteers for the establishment of the normality pattern. An average of nine images with the filter for fluorescein angiography was obtained for the formation of the image autofluorescence using Heidelberg Retina Angiograph2. The images of each group of patients were analyzed to verify common characteristics. The fundus autofluorescence of healthy volunteers showed the foveal area darker than the surrounding retina. The images of Stargardt macular dystrophy, in general, presented an oval central lesion, with reduced autofluorescence. The main alterations of the autofluorescence in patients with cone dystrophy were reduced foveal autofluorescence with a parafoveal ring of increased autofluorescence. In general, the images of retinitis pigmentosa showed outlying pigments with reduced autofluorescence, and of the foveal area, in some cases disorganization or reduced autofluorescence. The study showed the existence of patterns of fundus autofluorescence in the hereditary retinal diseases that allow the diagnosis and better interpretation of the pathogenesis of these diseases.

  6. Feasibility study of Raman spectroscopy for investigating the mouse retina in vivo

    Science.gov (United States)

    Manna, Suman K.; de Oliveira, Marcos A. S.; Zhang, Pengfei; Maleppat, Ratheesh K.; Chang, Che-Wei; Pugh, Edward N.; Chan, James W.; Zawadzki, Robert J.

    2018-02-01

    The use of Raman spectroscopy in biochemistry has been very successful, particularly because of its ability to identify elementary chemical species. However, application of this spectroscopic technique for in vivo assessment is often limited by autofluorescence, which make detection of Raman signatures difficult. The mouse eye has been used as an optical testbed for investigation of a variety of disease models and therapeutic pathways. Implementation of in vivo Raman spectroscopy in mice retina would be valuable but needs to be examined in context of the intrinsic auto-fluorescence artifact and potential light damage if high probing beam powers were used. To evaluate feasibility, a Raman system was built on a custom SLO/OCT platform allowing mouse positioning and morphological data acquisition along with the Raman signal from a desired retinal eccentricity. The performance of the Raman system was first assessed with a model eye consisting of polystyrene in the image plane (retina), using excitation wavelengths of 488 nm, 561 nm, and 785 nm to determine whether auto-fluorescence would be reduced at longer wavelengths. To improve the SNR, the combined system is featured with the optical compatibility for these three excitations such that their corresponding spectra from a typical region of interest can be acquired consecutively during single imaging run. Our results include emission spectra acquired over 10 s with excitation energy less than 160 J.s-1.m-2 for all wavelengths and corresponding retinal morphology for different mouse strains including WT, BALB/c and ABCA4-/-.

  7. In Silico Ocular Pharmacokinetic Modeling: Delivery of Topical FK962 to Retina.

    Science.gov (United States)

    Mori, Ayumi; Yabuta, Chiho; Kishimoto, Yayoi; Kozai, Seiko; Ohtori, Akira; Shearer, Thomas R; Azuma, Mitsuyoshi

    2017-09-01

    To establish the in silico ocular pharmacokinetic modeling for eye drops, and to simulate the dose regimen for FK962 in human choroid/retinal diseases. Pharmacokinetics for FK962 in vivo was performed by a single instillation of drops containing 0.1% 14 C-FK962 in rabbit eyes. Permeation of FK962 across the cornea, sclera, and choroid/retina was measured in vitro. Neurite elongation by FK962 was measured in cultured rat retinal ganglion cells. Parameters from the experimental data were used in an improved in silico model of ocular pharmacokinetics of FK962 in man. The mean concentration of FK962 in ocular tissues predicted by in silico modeling was consistent with in vivo results, validating the in silico model. FK962 rapidly penetrated into the anterior and posterior segments of the eye and then diffused into the vitreous body. The in silico pharmacokinetic modeling also predicted that a dose regimen of 0.0054% FK962 twice per day would produce biologically effective concentrations of FK962 in the choroid/retina, where FK962 facilitates rat neurite elongation. Our in silico model for ocular pharmacokinetics is useful (1) for predicting drug concentrations in specific ocular tissues after topical instillation, and (2) for suggesting the optimal dose regimens for eye drops. The pharmacodynamics for FK962 produced by this model may be useful for clinical trials against retinal neuropathy.

  8. Dopamine D2 receptors preferentially regulate the development of light responses of the inner retina

    Science.gov (United States)

    Tian, Ning; Xu, Hong-ping; Wang, Ping

    2014-01-01

    Retinal light responsiveness measured via electroretinography undergoes developmental modulation and is thought to be critically regulated by both visual experience and dopamine. The primary goal of this study is to determine whether the dopamine D2 receptor regulates the visual experience-dependent functional development of the retina. Accordingly, we recorded electroretinograms from wild type mice and mice with a genetic deletion of the gene that encodes the dopamine D2 receptor raised under normal cyclic light conditions and constant darkness. Our results demonstrate that mutation of the dopamine D2 receptors preferentially increases the amplitude of the inner retinal light responses evoked by high intensity light measured as oscillatory potentials in adult mice. During postnatal development, all three major components of electroretinograms, the a-wave, b-wave and oscillatory potentials, increase with age. Comparatively, mutation of the dopamine D2 receptors preferentially reduces the age-dependent increase of b-waves evoked by low intensity light. Light deprivation from birth reduces the amplitude of b-waves and completely diminishes the increased amplitude of oscillatory potentials. Taken together, these results demonstrate that the dopamine D2 receptor plays an important role in the activity-dependent functional development of the mouse retina. PMID:25393815

  9. Evidence for RPE65-independent vision in the cone-dominated zebrafish retina.

    Science.gov (United States)

    Schonthaler, Helia B; Lampert, Johanna M; Isken, Andrea; Rinner, Oliver; Mader, Andreas; Gesemann, Matthias; Oberhauser, Vitus; Golczak, Marcin; Biehlmaier, Oliver; Palczewski, Krzysztof; Neuhauss, Stephan C F; von Lintig, Johannes

    2007-10-01

    An enzyme-based cyclic pathway for trans to cis isomerization of the chromophore of visual pigments (11-cis-retinal) is intrinsic to vertebrate cone and rod vision. This process, called the visual cycle, is mostly characterized in rod-dominated retinas and essentially depends on RPE65, an all-trans to 11-cis-retinoid isomerase. Here we analysed the role of RPE65 in zebrafish, a species with a cone-dominated retina. We cloned zebrafish RPE65 and showed that its expression coincided with photoreceptor development. Targeted gene knockdown of RPE65 resulted in morphologically altered rod outer segments and overall reduced 11-cis-retinal levels. Cone vision of RPE65-deficient larvae remained functional as demonstrated by behavioural tests and by metabolite profiling for retinoids. Furthermore, all-trans retinylamine, a potent inhibitor of the rod visual cycle, reduced 11-cis-retinal levels of control larvae to a similar extent but showed no additive effects in RPE65-deficient larvae. Thus, our study of zebrafish provides in vivo evidence for the existence of an RPE65-independent pathway for the regeneration of 11-cis-retinal for cone vision.

  10. Ethambutol induces impaired autophagic flux and apoptosis in the rat retina

    Directory of Open Access Journals (Sweden)

    Shun-Ping Huang

    2015-08-01

    Full Text Available Ethambutol (EMB, an effective first-line antituberculosis agent, can cause serious visual impairment or irreversible vision loss in a significant number of patients. However, the mechanism underlying this ocular cytotoxicity remains to be elucidated. In this study, we found that there were statistically significant dose- and time-dependent increases in the number of cytoplasmic vacuoles and the level of cell death in EMB-treated RGC-5 cells (retinal ganglion cells. The protein kinase C (PKCδ inhibitor rottlerin markedly reduced the EMB-induced activation of caspase-3 and the subsequent apoptosis of RGC-5 cells. Western blot analysis revealed that the expression levels of class III PI3K, Beclin-1, p62 and LC3-II were upregulated, and LC3 immunostaining results showed activation of the early phase and inhibition of the late stage of autophagy in retinas of the EMB-intraperitoneal (IP-injected rat model. We further demonstrated that exposure to EMB induces autophagosome accumulation, which results from the impaired autophagic flux that is mediated by a PKCδ-dependent pathway, inhibits the PI3K/Akt/mTOR signaling pathway and leads to apoptotic death in retina neuronal cells. These results indicate that autophagy dysregulation in retinal neuronal cells might play a substantial role in EMB-induced optic neuroretinopathy.

  11. Quality Enhancement and Nerve Fibre Layer Artefacts Removal in Retina Fundus Images by Off Axis Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

    2011-01-01

    Retinal fundus images acquired with non-mydriatic digital fundus cameras are a versatile tool for the diagnosis of various retinal diseases. Because of the ease of use of newer camera models and their relative low cost, these cameras are employed worldwide by retina specialists to diagnose diabetic retinopathy and other degenerative diseases. Even with relative ease of use, the images produced by these systems sometimes suffer from reflectance artefacts mainly due to the nerve fibre layer (NFL) or other camera lens related reflections. We propose a technique that employs multiple fundus images acquired from the same patient to obtain a single higher quality image without these reflectance artefacts. The removal of bright artefacts, and particularly of NFL reflectance, can have great benefits for the reduction of false positives in the detection of retinal lesions such as exudate, drusens and cotton wool spots by automatic systems or manual inspection. If enough redundant information is provided by the multiple images, this technique also compensates for a suboptimal illumination. The fundus images are acquired in straightforward but unorthodox manner, i.e. the stare point of the patient is changed between each shot but the camera is kept fixed. Between each shot, the apparent shape and position of all the retinal structures that do not exhibit isotropic reflectance (e.g. bright artefacts) change. This physical effect is exploited by our algorithm in order to extract the pixels belonging to the inner layers of the retina, hence obtaining a single artefacts-free image.

  12. Toward automated selective retina treatment (SRT): an optical microbubble detection technique

    Science.gov (United States)

    Seifert, Eric; Park, Young-Gun; Theisen-Kunde, Dirk; Roh, Young-Jung; Brinkmann, Ralf

    2018-02-01

    Selective retina therapy (SRT) is an ophthalmological laser technique, targeting the retinal pigment epithelium (RPE) with repetitive microsecond laser pulses, while causing no thermal damage to the neural retina, the photoreceptors as well as the choroid. The RPE cells get damaged mechanically by microbubbles originating, at the intracellular melanosomes. Beneficial effects of SRT on Central Serous Retinopathy (CSR) and Diabetic Macula Edema (DME) have already been shown. Variations in the transmission of the anterior eye media and pigmentation variation of RPE yield in intra- and inter- individual thresholds of the pulse energy required for selective RPE damage. Those selective RPE lesions are not visible. Thus, dosimetry-systems, designed to detect microbubbles as an indicator for RPE cell damage, are demanded elements to facilitate SRT application. Therefore, a technique based on the evaluation of backscattered treatment light has been developed. Data of 127 spots, acquired during 10 clinical treatments of CSR patients, were assigned to a RPE cell damage class, validated by fluorescence angiography (FLA). An algorithm has been designed to match the FLA based information. A sensitivity of 0.9 with a specificity close to 1 is achieved. The data can be processed within microseconds. Thus, the process can be implemented in existing SRT lasers with an automatic pulse wise increasing energy and an automatic irradiation ceasing ability to enable automated treatment close above threshold to prevent adverse effects caused by too high pulse energy. Alternatively, a guidance procedure, informing the treating clinician about the adequacy of the actual settings, is possible.

  13. Simple explant culture of the embryonic chicken retina with long-term preservation of photoreceptors.

    Science.gov (United States)

    Thangaraj, Gopenath; Greif, Alexander; Layer, Paul G

    2011-10-01

    Structurally stable in vitro-model systems are indispensible to analyse neural development during embryogenesis, follow cellular differentiation and evaluate neurotoxicological or growth factor effects. Here we describe a three-dimensional, long-term in vitro-culture system of the embryonic chick retina which supports photoreceptor development. Retinal tissue was isolated from E6 chick eye, and cultured as explants by continuous orbital rotation to allow free floatation without any supporting materials. Young stage (E6) immature retinas were cultured for various time periods in order to follow the differentiation of cell types and plexiform layers by immunocytochemical methods. These explants could be cultured for at least 2-3 weeks with remarkable retention of retinal architecture. Interestingly, photoreceptors developed in the absence of pigment epithelium. Electron microscopic studies revealed formation of structures resembling photoreceptor outer segments, a feature not reported previously. Thus, the verification of photoreceptors, Müller cells, inner retinal cells and the inner plexiform layer described in our study establishes this explant culture as a valuable in vivo-like model system. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  14. Herniation of the retina in the central macula in an adult after iridocyclitis.

    Science.gov (United States)

    Guo, Qing; Pi, Yuli; Gao, Ting

    2014-09-01

    To report an unusual case of retinal hernia in the central macula in an adult after iridocyclitis. We report a case of a 46-year-old male who presented with blurred vision 2 weeks after complete resolution of acute iridocyclitis. Anterior segment and vitreous body examinations were unremarkable. Yellowish spots in the macular area were observed. Spectral domain optical coherence tomography (SD-OCT) imaging of the macula showed loss of the inner segment/outer segment (IS/OS) photoreceptor junction, with irregularity of the retinal pigment epithelium (RPE), and a V-shaped hernia of the retina into the choroid. The macular lesions emerged as mild window defects on fluorescein angiography and were visualized as hypofluorescent patches on all-phase indocyanine green angiography. At a one month follow-up, the best-corrected visual acuity improved to 20/20, which was followed by partial restoration of the IS/OS line, but a V-shaped hernia of the retina remained unchanged on SD-OCT. Ophthalmologists should be alert to the changes in OCT of the macula in patients after iridocyclitis and further research on the cause and possible predisposing factors for retinal herniation is warranted.

  15. Neutron diffraction analysis of the structure of rod photoreceptor membranes in intact retinas

    Energy Technology Data Exchange (ETDEWEB)

    Yaeger, M; Schoenborn, B; Engelman, D; Moore, P; Stryer, L

    1980-01-01

    Neutron diffraction data have been collected from samples containing ten dark-adapted Rana catesbiana bullfrog retinas in 100, 80, 60, 40, and 30% D/sub 2/O Ringer's solution using a step-scanning Soller slit diffractometer. Diffraction was also recorded from retinas equilibrated in D/sub 2/O solutions with varying osmolarity. Rocking curve experiments demonstrated that the rods are disoriented in a cylindrically symmetrical fashion. Structure factor amplitudes were obtained using semi-automated curve-fitting procedures, and phases were obtained by interpreting the D/sub 2/O-H/sub 2/O and osmotic Patterson maps. In D/sub 2/O Ringer's solution the first four structure factors are -353 +- 25, 246 +- 19, 434 +- 13 and 383 +- 19. Neutron scattering density profiles were calculated to 75 A resolution using these structure factors. These neutron diffraction data are consistent with the view that the lipid bilayer is a major structural motif of the rod outer segment disc membrane. Neutron Fourier syntheses in different mixtures of D/sub 2/O and H/sub 2/O indicate that the intradisc and extradisc spaces are predominantly aqueous, consistent with the increase in the intradisc and extradisc volumes as the Ringer's solution is made more hypotomic. In isotonic Ringer's solution, the thicknesses of the intradisc and extradisc spaces are about 36 A and 160 A, respectively, and the center-to-center separation between the 50 A thick lipid bilayer is 88 A.

  16. Argon laser-induced damage in the goldfish (C. auratus) retina following whole-body hyperthermia

    Science.gov (United States)

    Deaton, Michael A.; Lund, David J.; Schuschereba, Steven T.; Dahlberg, Ann M.; Cowan, Beth L.; Lester, Paul; Odom, Daniel G.

    1990-07-01

    The heat shock response is a phenomenon common to all cells and is characterized by an increase in the rate of synthesis of intracellular heat shock proteins (HSPs) . The response occurs following rapid transient increases in terrerature sufficient to cause stress but not cell death. HSPs appear to perform protective functions that raise the cell''s tolerance to diverse noxious stimuli. Thus we postulated that we could limit laser-induced retinal darriage through induction of the heat shock -response. Corrmon goldfish (C. auratus) made hyperthermic by immersion in 35C water for 15 minutes and radiolabeled with [355]methionine showed retinal liSPs with apparent molecular weights of 110 90 70 and 35 kilodaltons. To test the protective effects of HSPs against laser injury goldfish were made hyperthermic and 4 and 24 hr later their retinas were irradiated with argon laser light (51 4 . 5 nm spot size at the cornea 3. 0 mm irradiance 125 mW/cm2) . NonhyperLhermic animals served as controls. Following 24 hr of recovery fish were terminated and retinas fixed for histology. Fundus photographs were taken irrunediately after laser exposure . Lesion diameters were measured from fundus photographs and evaluated statistically. The mean retinal lesion diameters of fish not subjected to hyperthermJ. a laser exposed 4 hr post hyperLhermia and laser exposed 24 hr post hyperthermia were 10. 25 1. 4 SD 8. 82 2. 1 SD and 6. 78

  17. Direction-selective circuitry in rat retina develops independently of GABAergic, cholinergic and action potential activity.

    Directory of Open Access Journals (Sweden)

    Le Sun

    Full Text Available The ON-OFF direction selective ganglion cells (DSGCs in the mammalian retina code image motion by responding much more strongly to movement in one direction. They do so by receiving inhibitory inputs selectively from a particular sector of processes of the overlapping starburst amacrine cells, a type of retinal interneuron. The mechanisms of establishment and regulation of this selective connection are unknown. Here, we report that in the rat retina, the morphology, physiology of the ON-OFF DSGCs and the circuitry for coding motion directions develop normally with pharmacological blockade of GABAergic, cholinergic activity and/or action potentials for over two weeks from birth. With recent results demonstrating light independent formation of the retinal DS circuitry, our results strongly suggest the formation of the circuitry, i.e., the connections between the second and third order neurons in the visual system, can be genetically programmed, although emergence of direction selectivity in the visual cortex appears to require visual experience.

  18. Retina-like sensor based on a lens array with a large field of view.

    Science.gov (United States)

    Fan, Fan; Hao, Qun; Cheng, Xuemin

    2015-12-20

    This paper puts forward a retina-like sensor based on a lens array, which can be used in conventional optical systems. This sensor achieves log-polar mapping by dividing the imaging optical system's image plane using a lens array. In this paper the mathematical model has been set up with the relative structural parameters. Also, the simulation experiments and parameter analysis have been discussed to verify the reliability of this system. From the experiment results, it can be seen that this sensor realized the log-polar mapping with the transformed image output. Each lens corresponded to a circular region in the image plane with no crossover between different fields of view of adjacent lenses. When the number of rings changed, the relative error did not significantly change, and this error could be reduced to 1% when the number of lenses in each ring was increased. The work widely enlarged the application of this kind of sensor, which will lay a theoretical foundation for retina-like sensors.

  19. Host cell reactivation by fibroblasts from patients with pigmentary degeneration of the retina

    International Nuclear Information System (INIS)

    Lytle, C.D.; Tarone, R.E.; Barrett, S.F.; Robbins, J.H.; Wirtschafter, J.D.; Dupuy, J.-M.

    1983-01-01

    Cockayne syndrome (CS) is an autosomal recessive disease characterized by numerous clinical abnormalities including acute sun sensitivity and primary pigmentary degeneration of the retina. Cultured fibroblasts from CS patients are hypersensitive to ultraviolet radiation. Host cell reactivation of irradiated virus was studied in CS and in other diseases with retinal degeneration to evaluate repair. The survival of UV-irradiated Herpes simplex virus type 1 was determined in fibroblast lines from four normal donors, two patients with CS, one with both xeroderma pigmentosum (XP) and CS, and from several other patients with (Usher syndrome, olivopontocerebellar atrophy, retinitis pigmentosa) and without (XP, ataxia telangiectasia) primary pigmentary degeneration of the retina. The viral survival curves in all cell lines showed two components: a very sensitive initial component followed by an exponential, less sensitive component. The exponential component had greater sensitivity than normal in the case of the CS patients, the patient with both XP and CS, and the XP patient. It was proposed that patients with CS have defective repair of DNA which may be the cause of their retinal degeneration. (author)

  20. Host cell reactivation by fibroblasts from patients with pigmentary degeneration of the retina

    Energy Technology Data Exchange (ETDEWEB)

    Lytle, C.D. (Food and Drug Administration, Rockville, MD (USA)); Tarone, R.E.; Barrett, S.F.; Robbins, J.H. (National Cancer Inst., Bethesda, MD (USA)); Wirtschafter, J.D. (Minnesota Univ., Minneapolis (USA). Hospitals); Dupuy, J.M. (Quebec Univ., Laval-des-Rapides (Canada). Inst. Armand-Frappier)

    1983-05-01

    Cockayne syndrome (CS) is an autosomal recessive disease characterized by numerous clinical abnormalities including acute sun sensitivity and primary pigmentary degeneration of the retina. Cultured fibroblasts from CS patients are hypersensitive to ultraviolet radiation. Host cell reactivation of irradiated virus was studied in CS and in other diseases with retinal degeneration to evaluate repair. The survival of UV-irradiated Herpes simplex virus type 1 was determined in fibroblast lines from four normal donors, two patients with CS, one with both xeroderma pigmentosum (XP) and CS, and from several other patients with (Usher syndrome, olivopontocerebellar atrophy, retinitis pigmentosa) and without (XP, ataxia telangiectasia) primary pigmentary degeneration of the retina. The viral survival curves in all cell lines showed two components: a very sensitive initial component followed by an exponential, less sensitive component. The exponential component had greater sensitivity than normal in the case of the CS patients, the patient with both XP and CS, and the XP patient. It was proposed that patients with CS have defective repair of DNA which may be the cause of their retinal degeneration.

  1. Intrinsic bursting of AII amacrine cells underlies oscillations in the rd1 mouse retina.

    Science.gov (United States)

    Choi, Hannah; Zhang, Lei; Cembrowski, Mark S; Sabottke, Carl F; Markowitz, Alexander L; Butts, Daniel A; Kath, William L; Singer, Joshua H; Riecke, Hermann

    2014-09-15

    In many forms of retinal degeneration, photoreceptors die but inner retinal circuits remain intact. In the rd1 mouse, an established model for blinding retinal diseases, spontaneous activity in the coupled network of AII amacrine and ON cone bipolar cells leads to rhythmic bursting of ganglion cells. Since such activity could impair retinal and/or cortical responses to restored photoreceptor function, understanding its nature is important for developing treatments of retinal pathologies. Here we analyzed a compartmental model of the wild-type mouse AII amacrine cell to predict that the cell's intrinsic membrane properties, specifically, interacting fast Na and slow, M-type K conductances, would allow its membrane potential to oscillate when light-evoked excitatory synaptic inputs were withdrawn following photoreceptor degeneration. We tested and confirmed this hypothesis experimentally by recording from AIIs in a slice preparation of rd1 retina. Additionally, recordings from ganglion cells in a whole mount preparation of rd1 retina demonstrated that activity in AIIs was propagated unchanged to elicit bursts of action potentials in ganglion cells. We conclude that oscillations are not an emergent property of a degenerated retinal network. Rather, they arise largely from the intrinsic properties of a single retinal interneuron, the AII amacrine cell. Copyright © 2014 the American Physiological Society.

  2. Cell Cycle Regulation and Apoptotic Responses of the Embryonic Chick Retina by Ionizing Radiation.

    Directory of Open Access Journals (Sweden)

    Margot Mayer

    Full Text Available Ionizing radiation (IR exerts deleterious effects on the developing brain, since proliferative neuronal progenitor cells are highly sensitive to IR-induced DNA damage. Assuming a radiation response that is comparable to mammals, the chick embryo would represent a lower vertebrate model system that allows analysis of the mechanisms underlying this sensitivity, thereby contributing to the reduction, refinement and replacement of animal experiments. Thus, this study aimed to elucidate the radiation response of the embryonic chick retina in three selected embryonic stages. Our studies reveal a lack in the radiation-induced activation of a G1/S checkpoint, but rapid abrogation of G2/M progression after IR in retinal progenitors throughout development. Unlike cell cycle control, radiation-induced apoptosis (RIA showed strong variations between its extent, dose dependency and temporal occurrence. Whereas the general sensitivity towards RIA declined with ongoing differentiation, its dose dependency constantly increased with age. For all embryonic stages RIA occurred during comparable periods after irradiation, but in older animals its maximum shifted towards earlier post-irradiation time points. In summary, our results are in good agreement with data from the developing rodent retina, strengthening the suitability of the chick embryo for the analysis of the radiation response in the developing central nervous system.

  3. Efferent influences on the bioelectrical activity of the retina in primates.

    Science.gov (United States)

    Ortiz, Gonzalo; Odom, J Vernon; Passaglia, Christopher L; Tzekov, Radouil T

    2017-02-01

    The existence of retinopetal (sometimes referred to as "efferent" or "centrifugal") axons in the mammalian optic nerve is a topic of long-standing debate. Opposition is fading as efferent innervation of the retina has now been widely documented in rodents and other animals. The existence and function of an efferent system in humans and non-human primates has not, though, been definitively established. Such a feedback pathway could have important functional, clinical, and experimental significance to the field of vision science and ophthalmology. Following a comprehensive literature review (PubMed and Google Scholar, until July 2016), we present evidence regarding a system that can influence the bioelectrical activity of the retina in primates. Anatomical and physiological evidences are presented separately. Improvements in histological staining and the advent of retrograde nerve fiber tracers have allowed for more confidence in the identification of efferent optic nerve fibers, including back to their point of origin. Even with the accumulation of more modern anatomical and physiological evidence, some limitations and uncertainties about crucial details regarding the origins and role of a top-down, efferent system still exist. However, the summary of the evidence from earlier and more modern studies makes a compelling case in support of such a system in humans and non-human primates.

  4. Retina damage after exposure to UVA radiation on the early developmental stages of the Egyptian toad Bufo regularis Reuss

    Directory of Open Access Journals (Sweden)

    Alaa El-Din H. Sayed

    2016-10-01

    Full Text Available The present study was carried out to investigate the histological and histochemical changes in the retina on different developmental stages of Egyptian toad Bufo regularis. Our experiment started when tadpoles begin to feed. The adapted embryos are divided into 3 large tanks of 200 embryos each, collections of samples started from feeding age every three days. Both histological and histochemical results showed that the general architecture of the retina organ is correlated with the state of development. Therefore, it displayed different characteristic features depending on the investigated developmental stage starting from the larval stage (feeding began, stage 44 and ending with the post-metamorphic stage 66. Also, the present work aimed to study the chronic effects of UVA on the retina structure of B. regularis during development and metamorphosis for the first time.

  5. Simultaneous optical coherence tomography and lipofuscin autofluorescence imaging of the retina with a single broadband light source at 480nm.

    Science.gov (United States)

    Jiang, Minshan; Liu, Tan; Liu, Xiaojing; Jiao, Shuliang

    2014-12-01

    We accomplished spectral domain optical coherence tomography and auto-fluorescence microscopy for imaging the retina with a single broadband light source centered at 480 nm. This technique is able to provide simultaneous structural imaging and lipofuscin molecular contrast of the retina. Since the two imaging modalities are provided by the same group of photons, their images are intrinsically registered. To test the capabilities of the technique we periodically imaged the retinas of the same rats for four weeks. The images successfully demonstrated lipofuscin accumulation in the retinal pigment epithelium with aging. The experimental results showed that the dual-modal imaging system can be a potentially powerful tool in the study of age-related degenerative retinal diseases.

  6. P3-7: On Prototyping a Visual Prosthesis System with Artificial Retina and Optic Nerve Based on Arrayed Microfibers

    Directory of Open Access Journals (Sweden)

    Jian Hong Chen

    2012-10-01

    Full Text Available The traditional visual prosthesis system combines both a camera and a microelectrode array implanted on the visual neural network including retina, optic nerve, and visual cortex. Here, we introduce a new visual prosthesis system in which an artificial retina and optic nerve are demonstrated. The prototype of optic nerve for image transmission is comprised of arrayed PMMA microfibers with both ends connected with two planes, one functioned as retina for light reception and another attached to visual cortex. The microfibers are drawn from the thin film prepared by PMMA/chlorobenzene solution. Each micro fiber serves as an optical waveguide for the delivery of a single image pixel. It is demonstrated that with proper imaging optics, arrayed micro fibers could be lit as discrete light spots in accordance with the input image. Each micro fiber is expected to function as a stimulation unit for optical neural modulation in a visual prosthesis system.

  7. Retina Image Analysis and Ocular Telehealth: The Oak Ridge National Laboratory-Hamilton Eye Institute Case Study

    Energy Technology Data Exchange (ETDEWEB)

    Karnowski, Thomas Paul [ORNL; Giancardo, Luca [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

    2013-01-01

    Automated retina image analysis has reached a high level of maturity in recent years, and thus the question of how validation is performed in these systems is beginning to grow in importance. One application of retina image analysis is in telemedicine, where an automated system could enable the automated detection of diabetic retinopathy and other eye diseases as a low-cost method for broad-based screening. In this work we discuss our experiences in developing a telemedical network for retina image analysis, including our progression from a manual diagnosis network to a more fully automated one. We pay special attention to how validations of our algorithm steps are performed, both using data from the telemedicine network and other public databases.

  8. Circadian rhythms and light responsiveness of mammalian clock gene, Clock and BMAL1, transcripts in the rat retina.

    Science.gov (United States)

    Namihira, M; Honma, S; Abe, H; Tanahashi, Y; Ikeda, M; Honma, K

    1999-08-13

    Circadian expression and light-responsiveness of the mammalian clock genes, Clock and BMAL1, in the rat retina were examined by in situ hydbribization under constant darkness. A small but significant daily variation was detected in the Clock transcript level, but not in BMAL1. Light increased the Clock and BMAL1 expressions significantly when examined 60 min after exposure. The light-induced gene expression was phase-dependent for Clock and peaked at ZT2, while rather constant throughout the day for BMAL1. These findings suggest that Clock and BMAL1 play different roles in the generation of circadian rhytm in the retina from those in the suprachiasmatic nucleus. Different roles are also suggested between the two genes in the photic signal transduction in the retina.

  9. Inhibition of non-neuronal cell proliferation in the goldfish visual pathway affects the regenerative capacity of the retina

    International Nuclear Information System (INIS)

    Neuman, D.; Yerushalmi, A.; Schwartz, M.

    1983-01-01

    Proliferating cells associated with the visual pathway were found in the present study of affect the regenerative capacity of the goldfish retina following optic nerve injury. The contribution of these cells to the process of regeneration was investigated in the goldfish visual system by reducing their proliferation in the optic tract and tecta, using X-irradiation. The regenerative ability of the retina was then evaluated by the following parameters: sprouting from retinal explants, protein synthesis in the retina and accumulation of radiolabeled transported components in the tectum. X-irradiation of the visual system at an early stage of the regeneration process had a promoting effect whereas irradiation at a later stage resulted in a reduced capacity to regenerate. The results are discussed with respect to the possibility that proliferating cells, possibly glia, exert two contradictory contributions: an inhibitory effect at the site of injury, whereas distal to it, a supportive, perhaps trophic effect. (Auth.)

  10. Inhibition of non-neuronal cell proliferation in the goldfish visual pathway affects the regenerative capacity of the retina

    Energy Technology Data Exchange (ETDEWEB)

    Neuman, D.; Yerushalmi, A.; Schwartz, M. (Weizmann Inst. of Science, Rehovoth (Israel))

    1983-08-08

    Proliferating cells associated with the visual pathway were found in the present study of affect the regenerative capacity of the goldfish retina following optic nerve injury. The contribution of these cells to the process of regeneration was investigated in the goldfish visual system by reducing their proliferation in the optic tract and tecta, using X-irradiation. The regenerative ability of the retina was then evaluated by the following parameters: sprouting from retinal explants, protein synthesis in the retina and accumulation of radiolabeled transported components in the tectum. X-irradiation of the visual system at an early stage of the regeneration process had a promoting effect whereas irradiation at a later stage resulted in a reduced capacity to regenerate. The results are discussed with respect to the possibility that proliferating cells, possibly glia, exert two contradictory contributions: an inhibitory effect at the site of injury, whereas distal to it, a supportive, perhaps trophic effect.

  11. Neurite regeneration in adult rat retinas exposed to advanced glycation end-products and regenerative effects of neurotrophin-4.

    Science.gov (United States)

    Bikbova, Guzel; Oshitari, Toshiyuki; Yamamoto, Shuichi

    2013-10-09

    The purpose of this study was to determine the effect of low concentrations of advanced glycation end-products on neurite regeneration in isolated rat retinas, and to determine the effects of neurotrophin-4 on regeneration in advanced glycation end-products exposed retinas. Retinal explants of 4 adult Sprague-Dawley rats were cultured on collagen gel and were incubated in; (1) serum-free control culture media, (2) glucose-advanced glycation end-products-bovine serum albumin media, (3) glycolaldehyde-advanced glycation end-products-bovine serum albumin media, (4) glyceraldehyde-advanced glycation end-products-bovine serum albumin media, (5) glucose-advanced glycation end-products+neurotrophin-4 media, (6) glycolaldehyde-advanced glycation end-products+neurotrophin-4 media, or (7) glyceraldehyde-advanced glycation end-products+neurotrophin-4 supplemented culture media. After 7 days, the number of regenerating neurites from the explants was counted. Then, explants were fixed, cryosectioned, and stained for TUNEL. The ratio of TUNEL-positive cells to all cells in the ganglion cell layer was determined. Immunohistochemical examinations for the active-form of caspase-9 and apoptosis-inducing factor were performed. In retinas incubated with advanced glycation end-products containing media, the number of regenerating neurites were fewer than in retinas without advanced glycation end-products, and the number of TUNEL-positive cells and caspase-9- and apoptosis-inducing factor-immunopositive cells was significantly higher than in control media. Neurotrophin-4 supplementation increased the numbers of regenerating neuritis, and the number of TUNEL-positives, caspase-9-, and apoptosis-inducing factor-immunopositive cells were significantly fewer than that in advanced glycation end-products without neurotrophin-4 media. Low doses of advanced glycation end-products impede neurite regeneration in the rat retinas. Neurotrophin-4 significantly enhances neurite regeneration in

  12. 3D finite element modeling of epiretinal stimulation: Impact of prosthetic electrode size and distance from the retina.

    Science.gov (United States)

    Sui, Xiaohong; Huang, Yu; Feng, Fuchen; Huang, Chenhui; Chan, Leanne Lai Hang; Wang, Guoxing

    2015-05-01

    A novel 3-dimensional (3D) finite element model was established to systematically investigate the impact of the diameter (Φ) of disc electrodes and the electrode-to-retina distance on the effectiveness of stimulation. The 3D finite element model was established based on a disc platinum stimulating electrode and a 6-layered retinal structure. The ground electrode was placed in the extraocular space in direct attachment with sclera and treated as a distant return electrode. An established criterion of electric-field strength of 1000 Vm-1 was adopted as the activation threshold for RGCs. The threshold current (TC) increased linearly with increasing Φ and electrode-to-retina distance and remained almost unchanged with further increases in diameter. However, the threshold charge density (TCD) increased dramatically with decreasing electrode diameter. TCD exceeded the electrode safety limit for an electrode diameter of 50 µm at an electrode-to-retina distance of 50 to 200 μm. The electric field distributions illustrated that smaller electrode diameters and shorter electrode-to-retina distances were preferred due to more localized excitation of RGC area under stimulation of different threshold currents in terms of varied electrode size and electrode-to-retina distances. Under the condition of same-amplitude current stimulation, a large electrode exhibited an improved potential spatial selectivity at large electrode-to-retina distances. Modeling results were consistent with those reported in animal electrophysiological experiments and clinical trials, validating the 3D finite element model of epiretinal stimulation. The computational model proved to be useful in optimizing the design of an epiretinal stimulating electrode for prosthesis.

  13. Impact of type 1 diabetes mellitus and sitagliptin treatment on the neuropeptide Y system of rat retina

    DEFF Research Database (Denmark)

    Campos, Elisa J.; Martins, João; Brudzewsky, Dan

    2018-01-01

    1 diabetes mellitus (DM) and sitagliptin, a DPP-IV inhibitor, on the NPY system in the retina using an animal model.  Methods: Type 1 DM was induced in male Wistar rats by an intraperitoneal injection of streptozotocin. Starting 2weeks after DM onset, animals were treated orally with sitagliptin (5...... of NPY to all receptors. Sitagliptin alone reduced retinal NPY mRNA levels. The effects of DM on the NPY system were not affected by sitagliptin.  Conclusion: DM modestly affects the NPY system in the retina and these effects are not prevented by sitagliptin treatment. These observations suggest that DPP...

  14. Simultaneous in vivo imaging of melanin and lipofuscin in the retina with photoacoustic ophthalmoscopy and autofluorescence imaging

    Science.gov (United States)

    Zhang, Xiangyang; Zhang, Hao F.; Puliafito, Carmen A.; Jiao, Shuliang

    2011-08-01

    We combined photoacoustic ophthalmoscopy (PAOM) with autofluorescence imaging for simultaneous in vivo imaging of dual molecular contrasts in the retina using a single light source. The dual molecular contrasts come from melanin and lipofuscin in the retinal pigment epithelium (RPE). Melanin and lipofuscin are two types of pigments and are believed to play opposite roles (protective versus exacerbate) in the RPE in the aging process. We have successfully imaged the retina of pigmented and albino rats at different ages. The experimental results showed that multimodal PAOM system can be a potentially powerful tool in the study of age-related degenerative retinal diseases.

  15. Using induced pluripotent stem cell-derived conditional medium to attenuate the light-induced photodamaged retina of rats

    Directory of Open Access Journals (Sweden)

    Hua-Ming Chang

    2015-03-01

    Conclusion: The conditional medium of iPSCs contains plenty of cytoprotective, immune-modulative and rescue chemicals, contributing to the maintenance of neuronal function and retinal layers in light-damaged retina compared with apoptotic iPSC-CM and PBS. The antiapoptotic effect of iPSC-CM also shows promise in restoring damaged neurons. This result demonstrates that iPSC-CM may serve as an alternative to cell therapy alone to treat retinal light damage and maintain functional and structural integrity of the retina.

  16. Pathological alterations typical of human Tay-Sachs disease, in the retina of a deep-sea fish

    Science.gov (United States)

    Fishelson, L.; Delarea, Yacov; Galil, Bella S.

    Micrographs of retinas from the deep-sea fish Cataetyx laticeps revealed visual cells containing membranous whorls in the ellipsoids of the inner segments resulting from stretching and modifications of the mitochondria membranes and their cristae. These pathological structures seem to be homologous to the whorls observed in retinas of human carriers of Tay-Sachs disease. This disease, a genetic disorder, is found in humans and some mammals. Our findings in fish suggest that the gene responsible can be found throughout the vertebrate evolutionary tree, possibly dormant in most taxa.

  17. Caracterización molecular de las formas precoces de distrofia de retina recesivas y esporádicas en población española: amaurosis congénita de Leber y Retinosis pigmentaria de inicio precoz

    OpenAIRE

    Tatu, Sorina Daniela

    2016-01-01

    Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 27-01-2016 Esta tesis tiene embargado el acceso al texto completo hasta 27-07-2017 Las distrofias hereditarias de la retina (DR) son un conjunto de trastornos que se producen por una degeneración primaria y progresiva de fotorreceptores. Entre ellas, la amaurosis congénita de Leber (LCA) representa la forma más precoz y severa, ocasionando ...

  18. Prevalência da escoliose lombar em adultos Prevalencia de la escoliosis lumbar en adultos Prevalence of lumbar scoliosis in adults

    Directory of Open Access Journals (Sweden)

    Djalma Castro de Amorim Junior

    2011-01-01

    Full Text Available OBJETIVO: Avaliar a prevalência da escoliose degenerativa do adulto (tipo de novo em uma amostra da população brasileira. MÉTODOS: foram estudados 1149 exames radiográficos simples de abdome na incidência anteroposterior, realizados no Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto, no período de julho de 2008 a fevereiro de 2009. RESULTADOS: a prevalência da escoliose do adulto na amostra da população estudada foi de 1,74%, sendo maior na faixa etária entre 60 e 69 anos. Não foi observada diferença estatisticamente significativa (p = 0,41 entre os sexos, e a medida média do ângulo da escoliose foi de 19,1º. CONCLUSÃO: A PREVAlência da escoliose do adulto na amostra da população estudada está dentro dos resultados já apresentados na literatura.OBJETIVO: Evaluar la prevalenciade la escoliosis degenerativa del adulto (tipo de 'novo' en una muestra de la población. MÉTODOS: Se estudiaron 1149 radiografías de abdomen simple en proyección anteroposterior; esto se realizó en el Hospital de la Facultad de Medicina de Ribeirão Preto de julio de 2008 a febrero de 2009. RESULTADOS: La preponderanciade la escoliosis en la población de la muestra de adultos estudiados fue de 1,74%, siendo mayor en el grupo entre 60 y 69 años. No hubo diferencias significativas (p = 0,41 entre los sexos, y la medida promediodel ángulo de la escoliosis fue de 19,1º. CONCLUSIÓN: La prevalencia de la escoliosis en la muestra de adultos de la población estudiada está de acuerdo con los resultados presentados en la literatura.OBJECTIVE: to evaluate the prevalence of adult degenerative scoliosis (de novo in a sample of the population. METHODS: We studied 1149 plain anteroposterior abdominal radiographs in achieved in the Hospital das Clínicas of the Faculty of Medicine of Ribeirão Preto from July 2008 to February 2009. RESULTS: The prevalence of scoliosis in the adult population sample studied was 1.74%, being higher in the

  19. Temporal resolution of misfolded prion protein transport, accumulation, glial activation, and neuronal death in the retinas of mice inoculated with scrapie

    Science.gov (United States)

    Currently, there is a lack of pathologic landmarks to describe the progression of prion disease in vivo. The goal of this work was to determine the temporal relationship between the transport of misfolded prion protein from the brain to the retina, the accumulation of PrPSc in the retina, the respon...

  20. A Rede Brasileira de Produção Pública de Medicamentos na perspectiva da gestão de cadeias de suprimentos: o papel das TIC

    Directory of Open Access Journals (Sweden)

    Ana Luíza Pimenta de Souza

    2015-06-01

    Full Text Available A indústria farmacêutica configura-se como um oligopólio, com produtos diferenciados em segmentos de classes terapêuticas específicas. As grandes farmacêuticas globais concentram seus esforços de pesquisa e de comercialização nas doenças degenerativas, que trazem maior retorno financeiro. No Brasil, destaca-se a presença de um conjunto de laboratórios públicos, os quais compõem a Rede Brasileira de Produção Pública de Medicamentos (RBPPM, voltados para as necessidades do Sistema Único de Saúde (SUS, em grande parte negligenciadas pelas Big Pharmas. O objetivo deste estudo é investigar o uso pelos laboratórios farmacêuticos oficiais brasileiros das contribuições derivadas das tecnologias da informação e comunicação (TIC, no sentido da integração da cadeia de suprimentos da RBPPM. Em sua primeira fase, a pesquisa de campo foi realizada por meio de uma abordagem quantitativa em todos os laboratórios oficiais afiliados à Associação de Laboratórios Farmacêuticos Oficiais Brasileiros (Alfob. Essa análise permitiu levantar questões que foram aprofundadas por meio da abordagem qualitativa em três laboratórios selecionados da fase anterior. As evidências coletadas permitem concluir que os objetivos descritos na criação da RBPPM, cujo alcance poderia ser facilitado pela adoção dos atributos da GCS pela rede capitaneada pelo Ministério da Saúde, ainda são incipientes e erráticos. O estudo demonstrou que, apesar das evidências teóricas e empíricas a respeito da capacidade das TIC de integrar processos, os laboratórios públicos brasileiros ainda fazem pouco uso das tecnologias estudadas na gestão de cadeias de suprimento (GCS, e o desempenho das poucas ferramentas encontradas revelou-se incipiente e insatisfatório. É bem provável que essa evidência seja uma decorrência natural do fato de que a RBPPM não utilizava uma abordagem de GCS na época em que esta pesquisa foi realizada.

  1. Heparin-Binding EGF-like Growth Factor (HB-EGF) stimulates the proliferation of Müller glia-derived progenitor cells in avian and murine retinas

    Science.gov (United States)

    Todd, Levi; Volkov, Leo I.; Zelinka, Chris; Squires, Natalie; Fischer, Andy J.

    2015-01-01

    Müller glia can be stimulated to de-differentiate, proliferate and form Müller glia-derived progenitor cells (MGPCs) that regenerate retinal neurons. In the zebrafish retina, Heparin-Binding EGF-like Growth Factor (HB-EGF) may be one of the key factors that stimulate the formation of proliferating MGPCs. Currently nothing is known about the influence of HB-EGF on the proliferative potential of Müller glia in retinas of birds and rodents. In the chick retina, we found that levels of both hb-egf and egf-receptor are rapidly and transiently up-regulated following NMDA-induced damage. Although intraocular injections of HB-EGF failed to stimulate cell-signaling or proliferation of Müller glia in normal retinas, HB-EGF stimulated proliferation of MGPCs in damaged retinas. By comparison, inhibition of the EGF-receptor (EGFR) decreased the proliferation of MGPCs in damaged retinas. HB-EGF failed to act synergistically with FGF2 to stimulate the formation of MGPCs in the undamaged retina and inhibition of EGF-receptor did not suppress FGF2-mediated formation of MGPCs. In the mouse retina, HB-EGF stimulated the proliferation of Müller glia following NMDA-induced damage. Furthermore, HB-EGF stimulated not only MAPK-signaling in Müller glia/MGPCs, but also activated mTor- and Jak/Stat-signaling. We propose that levels of expression of EGFR are rate-limiting to the responses of Müller glia to HB-EGF and the expression of EGFR can be induced by retinal damage, but not by FGF2-treatment. We conclude that HB-EGF is mitogenic to Müller glia in both chick and mouse retinas, and HB-EGF is an important player in the formation of MGPCs in damaged retinas. PMID:26500021

  2. Transcriptional Changes in the Mouse Retina after Ocular Blast Injury: A Role for the Immune System.

    Science.gov (United States)

    Struebing, Felix L; King, Rebecca; Li, Ying; Chrenek, Micah A; Lyuboslavsky, Polina N; Sidhu, Curran S; Iuvone, P Michael; Geisert, Eldon E

    2018-01-01

    Ocular blast injury is a major medical concern for soldiers and explosion victims due to poor visual outcomes. To define the changes in gene expression following a blast injury to the eye, we examined retinal ribonucleic acid (RNA) expression in 54 mouse strains 5 days after a single 50-psi overpressure air wave blast injury. We observe that almost 40% of genes are differentially expressed with a false discovery rate (FDR) of immune system are activated. Accompanied by lymphocyte invasion into the inner retina, blast injury also results in progressive loss of visual function and retinal ganglion cells (RGCs). Collectively, these data demonstrate how systems genetics can be used to put meaning to the transcriptome changes following ocular blast injury that eventually lead to blindness.

  3. Synthesis of taurine–fluorescein conjugate and evaluation of its retina-targeted efficiency in vitro

    Directory of Open Access Journals (Sweden)

    Meihong Huang

    2014-12-01

    Full Text Available In this work, retinal penetration of fluorescein was achieved in vitro by covalent attachment of taurine to fluorescein, yielding the F–Tau conjugate. Nuclear magnetic resonance (NMR and high resolution mass spectrometry (HRMS were used to confirm the successful synthesis of F–Tau. The cellular uptake of F–Tau in adult retinal pigment epithelial cells (ARPE-19 and human retinal microvascular endothelial cells (hRMECs was visualized via confocal scanning microscopy. The results indicated an improvement of solubility and a reduction of logP of F–Tau compared with fluorescein. As compared with fluorescein, F–Tau showed little toxicity, and was retained longer by cells in uptake experiments. F–Tau also displayed higher transepithelial permeabilities than fluorescein in ARPE-19 and hRMECs monolayer cells (P<0.05. These results showed that taurine may be a useful ligand for targeting small-molecule hydrophobic pharmaceuticals into the retina.

  4. Fundus autofluorescence imaging in dry AMD: 2014 Jules Gonin lecture of the Retina Research Foundation.

    Science.gov (United States)

    Holz, Frank G; Steinberg, Julia S; Göbel, Arno; Fleckenstein, Monika; Schmitz-Valckenberg, Steffen

    2015-01-01

    Fundus autofluorescence (FAF) imaging allows for topographic mapping of intrisnic fluorophores in the retinal pigment epithelial cell monolayer, as well as mapping of other fluorophores that may occur with disease in the outer retina and the sub-neurosensory space. FAF imaging provides information not obtainable with other imaging modalities. Near-infrared fundus autofluorescence images can also be obtained in vivo, and may be largely melanin-derived. FAF imaging has been shown to be useful in a wide spectrum of macular and retinal diseases. The scope of applications now includes identification of diseased RPE in macular/retinal diseases, elucidating pathophysiological mechanisms, identification of early disease stages, refined phenotyping, identification of prognostic markers for disease progression, monitoring disease progression in the context of both natural history and interventional therapeutic studies, and objective assessment of luteal pigment distribution and density as well as RPE melanin distribution. Here, we review the use of FAF imaging in various phenotypic manifestations of dry AMD.

  5. Geographic atrophy segmentation in infrared and autofluorescent retina images using supervised learning.

    Science.gov (United States)

    Devisetti, K; Karnowski, T P; Giancardo, L; Li, Y; Chaum, E

    2011-01-01

    Geographic Atrophy (GA) of the retinal pigment epithelium (RPE) is an advanced form of atrophic age-related macular degeneration (AMD) and is responsible for about 20% of AMD-related legal blindness in the United States. Two different imaging modalities for retinas, infrared imaging and autofluorescence imaging, serve as interesting complimentary technologies for highlighting GA. In this work we explore the use of neural network classifiers in performing segmentation of GA in registered infrared (IR) and autofluorescence (AF) images. Our segmentation achieved a performance level of 82.5% sensitivity and 92.9% specificity on a per-pixel basis using hold-one-out validation testing. The algorithm, feature extraction, data set and experimental results are discussed and shown.

  6. Radiation therapy in and about the retina, optic nerve, and anterior visual pathway: psychophysical assessment

    International Nuclear Information System (INIS)

    Fitzgerald, C.R.; Enoch, J.M.; Temme, L.A.

    1981-01-01

    Visual changes may develop in patients receiving radiation therapy for malignant neoplasms in and about the optic nerve and anterior visual pathway. Cases have been studied using a series of psychophysical tests, including kinetic perimetry, increment threshold determinations, Flashing Repeat Static Test, and sustained- and transient-like functions. A characteristic time-dependent reduction in sensitivity has been identified in these patients. This finding, in addition to the presence of nerve fiber bundle defects, appears to place the pathologic changes in the axon of the ganglion cell posterior to the lamina cribrosa. Any change in the sustained- and transient-like functions, the organization of which appears to be in the neural retina, was seen only if a concomitant radiation retinopathy was identified

  7. Radiation therapy in and about the retina, optic nerve, and anterior visual pathway. Psychophysical assessment

    International Nuclear Information System (INIS)

    Fitzgerald, C.R.; Enoch, J.M.; Temme, L.A.

    1981-01-01

    Visual changes may develop in patients receiving radiation therapy for malignant neoplasms in and about the optic nerve and anterior visual pathway. Cases have been studied using a series of psychophysical tests, including kinetic perimetry, increment threshold determinations, Flashing Repeat Static Test, and sustained- and transient-like functions. A characteristic time-dependent reduction in sensitivity has been identified in these patients. This finding, in addition to the presence of nerve fiber bundle defects, appears to place the pathologic changes in the axon of the ganglion cell posterior to the lamina cribrosa. Any change in the sustained- and transient-like functions, the organization of which appears to be in the neural retina, was seen only if a concomitant radiation retinopathy was identified

  8. The artificial retina for track reconstruction at the LHC crossing rate

    CERN Document Server

    Abba, A.; Citterio, M.; Caponio, F.; Cusimano, A.; Geraci, A.; Marino, P.; Morello, M.J.; Neri, N.; Punzi, G.; Piucci, A.; Ristori, L.; Spinella, F.; Stracka, S.; Tonelli, D.

    2016-01-01

    We present the results of an R&D study for a specialized processor capable of precisely reconstructing events with hundreds of charged-particle tracks in pixel and silicon strip detectors at $40\\,\\rm MHz$, thus suitable for processing LHC events at the full crossing frequency. For this purpose we design and test a massively parallel pattern-recognition algorithm, inspired to the current understanding of the mechanisms adopted by the primary visual cortex of mammals in the early stages of visual-information processing. The detailed geometry and charged-particle's activity of a large tracking detector are simulated and used to assess the performance of the artificial retina algorithm. We find that high-quality tracking in large detectors is possible with sub-microsecond latencies when the algorithm is implemented in modern, high-speed, high-bandwidth FPGA devices.

  9. The artificial retina for track reconstruction at the LHC crossing rate

    Science.gov (United States)

    Abba, A.; Bedeschi, F.; Citterio, M.; Caponio, F.; Cusimano, A.; Geraci, A.; Marino, P.; Morello, M. J.; Neri, N.; Punzi, G.; Piucci, A.; Ristori, L.; Spinella, F.; Stracka, S.; Tonelli, D.

    2016-04-01

    We present the results of an R&D study for a specialized processor capable of precisely reconstructing events with hundreds of charged-particle tracks in pixel and silicon strip detectors at 40 MHz, thus suitable for processing LHC events at the full crossing frequency. For this purpose we design and test a massively parallel pattern-recognition algorithm, inspired to the current understanding of the mechanisms adopted by the primary visual cortex of mammals in the early stages of visual-information processing. The detailed geometry and charged-particle's activity of a large tracking detector are simulated and used to assess the performance of the artificial retina algorithm. We find that high-quality tracking in large detectors is possible with sub-microsecond latencies when the algorithm is implemented in modern, high-speed, high-bandwidth FPGA devices.

  10. Transferin concentration and location during formation of chick retina: developmental correlates

    International Nuclear Information System (INIS)

    Zeevalk, G.D.; Hyndman, A.G.

    1988-01-01

    The amount of transferrin in chick retina was measured during development and compared to transferrin location seen immunocytochemically. Between embryonic day 6 (E6), and 5 days post hatching, two periods occur in which transferrin concentrations rise sharply and decline. During the first, transferrin concentration rises 5-fold between E6 and 10, then rapidly declines by E14. A second increase begins on E17 and peaks by E19-20. Immunocytochemical findings demonstrate that during the first rise in concentration, transferrin is located primarily in neuritic layers. Later in development, when levels again increase, newly forming photoreceptor outer segments are strongly transferrin positive. These findings are discussed in light of developmental events occurring during retinal maturation (author)

  11. microRNA expression in the neural retina: Focus on Müller glia.

    Science.gov (United States)

    Quintero, Heberto; Lamas, Mónica

    2018-03-01

    The neural retina hosts a unique specialized type of macroglial cell that not only preserves retinal homeostasis, function, and integrity but also may serve as a source of new neurons during regenerative processes: the Müller cell. Precise microRNA-driven mechanisms of gene regulation impel and direct the processes of Müller glia lineage acquisition from retinal progenitors during development, the triggering of their response to retinal degeneration and, in some cases, Müller cell reprogramming and regenerative events. In this review we survey the recent reports describing, through functional assays, the regulatory role of microRNAs in Müller cell physiology, differentiation potential, and retinal pathology. We discuss also the evidence based on expression analysis that points out the relevance of a Müller glia-specific microRNA signature that would orchestrate these processes. © 2017 Wiley Periodicals, Inc.

  12. Dust Plate, Retina, Photograph: Imaging on Experimental Surfaces in Early Nineteenth-Century Physics.

    Science.gov (United States)

    Ramalingam, Chitra

    2015-09-01

    This article explores the entangled histories of three imaging techniques in early nineteenth-century British physical science, techniques in which a dynamic event (such as a sound vibration or an electric spark) was made to leave behind a fixed trace on a sensitive surface. Three categories of "sensitive surface" are examined in turn: first, a metal plate covered in fine dust; second, the retina of the human eye; and finally, a surface covered with a light-sensitive chemical emulsion (a photographic plate). For physicists Michael Faraday and Charles Wheatstone, and photographic pioneer William Henry Fox Talbot, transient phenomena could be studied through careful observation and manipulation of the patterns wrought on these different surfaces, and through an understanding of how the imaging process unfolded through time. This exposes the often-ignored materiality and temporality of epistemic practices around nineteenth-century scientific images said to be "drawn by nature."

  13. Patterns of cell proliferation and cell death in the developing retina and optic tectum of the brown trout.

    NARCIS (Netherlands)

    Candal, E.; Anadon, R.; Grip, W.J. de; Rodriguez-Moldes, I.

    2005-01-01

    We have analyzed the patterns of cell proliferation and cell death in the retina and optic tectum of the brown trout (Salmo trutta fario) throughout embryonic and postembryonic stages. Cell proliferation was detected by immunohistochemistry with an antibody against the proliferating cell nuclear

  14. Expression and location of mRNAs encoding multiple forms of secretory phospholipase A2 in the rat retina

    DEFF Research Database (Denmark)

    Kolko, Miriam; Christoffersen, Nanna R; Barreiro, Sebastian G

    2004-01-01

    of sPLA(2)s in neuronal signaling and survival [Kolko et al. (1996) J. Biol. Chem. 271: 32722-32728]. To date, no retinal sPLA(2)s have been cloned or characterized. We evaluated the existence and abundance of sPLA(2) subtypes in rat retina and explored their possible involvement in light...

  15. Heat shock protein 70 and heat shock protein 90 expression in light- and dark-adapted adult octopus retinas.

    Science.gov (United States)

    Ochoa, Gina H; Clark, Ying Mei; Matsumoto, Brian; Torres-Ruiz, Jose A; Robles, Laura J

    2002-02-01

    Light- and dark-adaptation leads to changes in rhabdom morphology and photopigment distribution in the octopus retina. Molecular chaperones, including heat shock proteins (Hsps), may be involved in specific signaling pathways that cause changes in photoreceptor actin- and tubulin-based cytoskeletons and movement of the photopigments, rhodopsin and retinochrome. In this study, we used immunoblotting, in situ RT-PCR, immunofluorescence and confocal microscopy to localize the inducible form of Hsp70 and the larger Hsp90 in light- and dark-adapted and dorsal and ventral halves of adult octopus retinas. The Hsps showed differences in distribution between the light and dark and in dorsal vs. ventral position in the retina. Double labeling confocal microscopy co-localized Hsp70 with actin and tubulin, and Hsp90 with the photopigment, retinochrome. Our results demonstrate the presence of Hsp70 and Hsp90 in otherwise non-stressed light- and dark-adapted octopus retinas. These Hsps may help stabilize the cytoskeleton, important for rhabdom structure, and are perhaps involved in the redistribution of retinochrome in conditions of light and dark.

  16. Progenitor cells from the porcine neural retina express photoreceptor markers after transplantation to the subretinal space of allorecipients

    DEFF Research Database (Denmark)

    Klassen, Henry; Kiilgaard, Jens Folke; Zahir, Tasneem

    2007-01-01

    Work in rodents has shown that cultured retinal progenitor cells (RPCs) integrate into the degenerating retina, thus suggesting a potential strategy for treatment of similar degenerative conditions in humans. To demonstrate the relevance of the rodent work to large animals, we derived progenitor...

  17. Retina tissue engineering by conjunctiva mesenchymal stem cells encapsulated in fibrin gel: Hypotheses on novel approach to retinal diseases treatment.

    Science.gov (United States)

    Soleimannejad, Mostafa; Ebrahimi-Barough, Somayeh; Nadri, Samad; Riazi-Esfahani, Mohammad; Soleimani, Masoud; Tavangar, Seyed Mohammad; Ai, Jafar

    2017-04-01

    Retinitis pigmentosa (RP) and age related macular degeneration (AMD) are two retinal diseases that progress by photoreceptor cells death. In retinal transplantation studies, stem and progenitor cells inject into the sub retinal space or vitreous and then these cells can be migrate to the site of retinal degeneration and locate in the host retina and restitute vision. Our hypothesis suggests that using human conjunctiva stem cells (as the source for increasing the number of human stem cells progenitor cells in retina dysfunction diseases) with fibrin gel and also assessing its relating in vitro (cellular and molecular processes) and in vivo (vision tests and pathology) could be a promising strategy for treatment of AMD and RP disorders. In this idea, we describe a novel approach for retina tissue engineering with differentiation of conjunctiva mesenchymal stem cells (CJMSCs) into photoreceptor-like cells in fibrin gel with induction medium contain taurine. For assessment of differentiation, immunocytochemistry and real time PCR are used for the expression of Rhodopsin, RPE65, Nestin as differentiated photoreceptor cell markers in 2D and 3D culture. The results show that fibrin gel will offer a proper 3D scaffold for CJMSCs derived photoreceptor cell-like cells. Application of immune-privileged, readily available sources of adult stem cells like human conjunctiva stem cells with fibrin gel would be a promising strategy to increase the number of photoreceptor progenitor cells and promote involuntary angiogenesis needed in retina layer repair and regeneration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. La complejidad de las distrofias hereditarias de la retina: un obstáculo y un reto

    OpenAIRE

    Martín Nieto, José

    2014-01-01

    ACTO conjunto de FARPE-FUNDALUCE con la SEBBM en el marco de su XXXVII Congreso. Conferencia: La complejidad de las distrofias hereditarias de la retina: Un obstáculo y un reto (José Martín Nieto).

  19. Color opponency in cone-driven horizontal cells in carp retina. Aspecific pathways between cones and horizontal cells

    NARCIS (Netherlands)

    Kamermans, M.; van Dijk, B. W.; Spekreijse, H.

    1991-01-01

    The spectral and dynamic properties of cone-driven horizontal cells in carp retina were evaluated with silent substitution stimuli and/or saturating background illumination. The aim of this study was to describe the wiring underlying the spectral sensitivity of these cells. We will present

  20. Localization, distribution, and connectivity of neuropeptide Y in the human and porcine retinas-A comparative study.

    Science.gov (United States)

    Christiansen, Anders Tolstrup; Kiilgaard, Jens Folke; Klemp, Kristian; Woldbye, David Paul Drucker; Hannibal, Jens

    2018-04-17

    Neuropeptide Y (NPY) is a peptide neurotransmitter abundantly expressed in the mammalian retina. Since its discovery, NPY has been studied in retinas of several species, but detailed characterization of morphology, cell-type, and connectivity has never been conducted in larger mammals including humans and pigs. As the pig due to size and cellular composition is a well-suited animal for retinal research, we chose to compare the endogenous NPY system of the human retina to that of pigs to support future research in this field. In the present study, using immunohistochemistry, confocal microscopy and 3D reconstructions, we found NPY to be expressed in GABAergic and calretinin-immunoreactive (-ir) amacrine cells of both species as well as parvalbumin-ir amacrine cells of humans. Furthermore, we identified at least two different types of medium- to wide-field NPY-ir amacrine cells. Finally, we detected likely synaptic appositions between the NPY-ir amacrine cells and melanopsin- and nonmelanopsin-ir ganglion cells, GABAergic and dopaminergic amacrine cells, rod bipolar cells, and horizontal cells, suggesting that NPY-ir cells play diverse roles in modulation of both image and non-image forming retinal signaling. These findings extend existing knowledge on NPY and NPY-expressing cells in the human and porcine retina showing a high degree of comparability. The extensive distribution and connectivity of NPY-ir cells described in the present study further highlights the potential importance of NPY signaling in retinal function. © 2018 Wiley Periodicals, Inc.

  1. Endothelial cell hypertrophy induced by vascular endothelial growth factor in the retina: new insights into the pathogenesis of capillary nonperfusion

    NARCIS (Netherlands)

    Hofman, P.; van Blijswijk, B. C.; Gaillard, P. J.; Vrensen, G. F.; Schlingemann, R. O.

    2001-01-01

    OBJECTIVE: To investigate the mechanism leading to capillary nonperfusion of the retina in a monkey model of vascular endothelial growth factor A (VEGF)-induced retinopathy in which capillary closure occurs in a late stage after VEGF treatment. METHODS: Two monkeys received 4 intravitreous

  2. Expression and localization of ionotropic glutamate receptor subunits in the goldfish retina--an in situ hybridization and immunocytochemical study

    NARCIS (Netherlands)

    Vandenbranden, C. A.; Kamphuis, W.; Nunes Cardozo, B.; Kamermans, M.

    2000-01-01

    The expression and distribution of AMPA, kainate and NMDA glutamate receptor subunits was studied in the goldfish retina. For the immunocytochemical localization of the AMPA receptor antisera against GluR2, GluR2/3 and GluR4 were used, and for in situ hybridization rat specific probes for GluR1 and

  3. Tratamento cirúrgico da retinopatia diabética

    Directory of Open Access Journals (Sweden)

    Nelson Alexandre Sabrosa

    2013-06-01

    Full Text Available A retinopatia diabética é a causa mais frequente de cegueira na população ativa nos países desenvolvidos. A prevalência da retinopatia diabética aumenta com a duração da diabetes, e praticamente 100% dos pacientes com diabetes tipo I (DM I e mais do que 60% dos pacientes com o tipo II (DM II apresentarão algum sinal de retinopatia após 20 anos. Além de um controle sistêmico rigoroso dos níveis glicêmicos, lipídicos, colesterol e da pressão arterial, o exame oftalmológico de rotina, com a identificação precoce da retinopatia diabética, podem detectar anormalidades em estágios primários, o que possibilita o tratamento ainda na fase inicial do problema; o uso adequado da fotocoagulação e a utilização da terapia antiangiogênica pode reduzir o número de pacientes com hemorragia vítrea ou descolamento tracional da retina. Infelizmente, em vários pacientes, a retinopatia progride mesmo com as melhores condutas tomadas pelo paciente e pelo oftalmologista, embora vários olhos podem se beneficiar com o tratamento cirúrgico, a vitrectomia posterior via pars plana. Esta revisão apresenta as indicações atuais para cirurgia vitreorretiniana em pacientes portadores de retinopatia diabética proliferativa.

  4. Regulation of C3 Activation by the Alternative Complement Pathway in the Mouse Retina.

    Directory of Open Access Journals (Sweden)

    Jennifer A E Williams

    Full Text Available The purpose of this study was to examine the retinas of mice carrying hemizygous and null double deletions of Cfb-/- and Cfh-/-, and to compare these with the single knockouts of Cfb, Cfh and Cfd. Retinas were isolated from wild type (WT, Cfb-/-/Cfh-/-, Cfb-/-/Cfh+/-, Cfh-/-/Cfb+/-, Cfb-/-, Cfh-/- Cfd-/-, and Cfd+/- mice. Complement proteins were evaluated by western blotting, ELISA and immunocytochemistry, and retinal morphology was assessed using toluidine blue stained semi-thin sections. WT mice showed staining for C3 and its breakdown products in the retinal vasculature and the basal surface of the retinal pigment epithelium (RPE. Cfb-/- mice exhibited a similar C3 staining pattern to WT in the retinal vessels but a decrease in C3 and its breakdown products at the basal surface of the RPE. Deletion of both Cfb and Cfh restored C3 to levels similar to those observed in WT mice, however this reversal of phenotype was not observed in Cfh-/-/Cfb+/- or Cfb-/-/Cfh+/- mice. Loss of CFD caused an increase in C3 and a decrease in C3 breakdown products along the basal surface of the RPE. Overall the retinal morphology and retinal vasculature did not appear different across the various genotypes. We observed that C3 accumulates at the basal RPE in Cfb-/-, Cfb-/-/Cfh-/-, Cfb-/-/Cfh+/-, Cfd-/- and WT mice, but is absent in Cfh-/- and Cfh-/-/Cfb+/- mice, consistent with its consumption in the serum of mice lacking CFH when CFB is present. C3 breakdown products along the surface of the RPE were either decreased or absent when CFB, CFH or CFD was deleted or partially deleted.

  5. [Selective retina therapy in central serous chorioretinopathy with detachment of the pigmentary epithelium].

    Science.gov (United States)

    Klatt, C; Elsner, H; Pörksen, E; Brinkmann, R; Bunse, A; Birngruber, R; Roider, J

    2006-10-01

    Selective Retina Therapy (SRT) is a new and innovative laser treatment modality that selectively treats the retinal pigmentary epithelium while sparing the photoreceptors. This therapeutic concept appears to be particularly suitable for treating patients with acute or chronic central serous chorioretinopathy (CSC). We present preliminary results obtained in five patients who had CSC associated with pigmentary epithelium detachment (PED) and serous subretinal fluid (SRF) and who were treated with SRT. This case series was made up of five male patients (mean age 47 years) with chronic CSC and SRF resulting from PED. Examinations performed before and at 1 month and 3 months after the treatment were: BCVA, FLA, OCT (Zeiss OCT III). For SRT, confluent treatment of the PED (area of leakage) was carried out using a pulsed frequency-doubled, Q-switched Nd-YLF prototype laser (lambda=527 nm, t= 1.7 s, 100 Hz, energy = 150-250 J). Best corrected visual acuity at baseline was 0.53, while after 4 weeks it was 0.56 and after 12 weeks, 0.5. At baseline leakage was seen at the PED on fluorescein angiography in all patients. After 4 weeks leakage activity was no longer noted on angiography in 4 of 5 patients. OCT at baseline showed SRF at the edge of the PED in all patients, but in 4 of the 5 patients this was no longer detectable after 4 weeks. SRT is a safe and effective treatment for patients with CSC in which PED has caused SRF. Not a single case of rip syndrome was observed in this study, even though the PED was treated confluently. Since SRT spares the photoreceptors it is particularly suitable for the treatment of CSC, especially when the origin of leakage is located close to the fovea. The results indicate that SRT leads to reconstruction of the outer blood-retina barrier.

  6. Survey: technique of performing intravitreal injection among members of the Brazilian Retina and Vitreous Society (SBRV

    Directory of Open Access Journals (Sweden)

    Helio F. Shiroma

    2015-02-01

    Full Text Available Purpose: To evaluate and describe the precautions involved in the technique of intravitreal injection of antiangiogenic drugs adopted by the ophthalmologists who are members of the Brazilian Society of Retina and Vitreous (SBRV. Methods: A questionnaire containing 22 questions related to precautions taken before, during, and after intravitreal injection was sent electronically to 920 members of SBRV between November 15, 2013 and April 31, 2014. Results: 352 responses (38% were obtained. There was a predominance of men (76% from the southwest region of Brazil (51%. The professional experience varied between 6 and 15 years after medical specialization (50%. Most professionals (76% performed an average of 1 to 10 intravitreal injections a week, and 88% of the procedures were performed in the operating room using povidone iodine (99%, sterile gloves, and blepharostat (94%. For inducing topical anesthesia, usage of anesthetic eye drops was the most used technique (65%. Ranibizumab (Lucentis® was the most common drug (55%, and age-related macular degeneration (AMD was the most treated disease (57%. Regarding the complications treated, 6% of the ophthalmologists had treated at least one case of retinal detachment, 20% had treated cases of endophthalmitis, 9% had treated cases of vitreous hemorrhage, and 12% had encountered cases of crystalline lens touch. Conclusion: Intravitreal injection is a procedure routinely performed by retina specialists and has a low incidence of complications. Performing the procedure in the operating room using an aseptic technique was preferred by most of the respondents. Ranibizumab was the most used drug, and AMD was the most treated disease.

  7. Comparative genomics identification of a novel set of temporally regulated hedgehog target genes in the retina.

    Science.gov (United States)

    McNeill, Brian; Perez-Iratxeta, Carol; Mazerolle, Chantal; Furimsky, Marosh; Mishina, Yuji; Andrade-Navarro, Miguel A; Wallace, Valerie A

    2012-03-01

    The hedgehog (Hh) signaling pathway is involved in numerous developmental and adult processes with many links to cancer. In vertebrates, the activity of the Hh pathway is mediated primarily through three Gli transcription factors (Gli1, 2 and 3) that can serve as transcriptional activators or repressors. The identification of Gli target genes is essential for the understanding of the Hh-mediated processes. We used a comparative genomics approach using the mouse and human genomes to identify 390 genes that contained conserved Gli binding sites. RT-qPCR validation of 46 target genes in E14.5 and P0.5 retinal explants revealed that Hh pathway activation resulted in the modulation of 30 of these targets, 25 of which demonstrated a temporal regulation. Further validation revealed that the expression of Bok, FoxA1, Sox8 and Wnt7a was dependent upon Sonic Hh (Shh) signaling in the retina and their regulation is under positive and negative controls by Gli2 and Gli3, respectively. We also show using chromatin immunoprecipitation that Gli2 binds to the Sox8 promoter, suggesting that Sox8 is an Hh-dependent direct target of Gli2. Finally, we demonstrate that the Hh pathway also modulates the expression of Sox9 and Sox10, which together with Sox8 make up the SoxE group. Previously, it has been shown that Hh and SoxE group genes promote Müller glial cell development in the retina. Our data are consistent with the possibility for a role of SoxE group genes downstream of Hh signaling on Müller cell development. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  8. Gap junctional coupling in the vertebrate retina: variations on one theme?

    Science.gov (United States)

    Völgyi, Béla; Kovács-Oller, Tamás; Atlasz, Tamás; Wilhelm, Márta; Gábriel, Róbert

    2013-05-01

    Gap junctions connect cells in the bodies of all multicellular organisms, forming either homologous or heterologous (i.e. established between identical or different cell types, respectively) cell-to-cell contacts by utilizing identical (homotypic) or different (heterotypic) connexin protein subunits. Gap junctions in the nervous system serve electrical signaling between neurons, thus they are also called electrical synapses. Such electrical synapses are particularly abundant in the vertebrate retina where they are specialized to form links between neurons as well as glial cells. In this article, we summarize recent findings on retinal cell-to-cell coupling in different vertebrates and identify general features in the light of the evergrowing body of data. In particular, we describe and discuss tracer coupling patterns, connexin proteins, junctional conductances and modulatory processes. This multispecies comparison serves to point out that most features are remarkably conserved across the vertebrate classes, including (i) the cell types connected via electrical synapses; (ii) the connexin makeup and the conductance of each cell-to-cell contact; (iii) the probable function of each gap junction in retinal circuitry; (iv) the fact that gap junctions underlie both electrical and/or tracer coupling between glial cells. These pan-vertebrate features thus demonstrate that retinal gap junctions have changed little during the over 500 million years of vertebrate evolution. Therefore, the fundamental architecture of electrically coupled retinal circuits seems as old as the retina itself, indicating that gap junctions deeply incorporated in retinal wiring from the very beginning of the eye formation of vertebrates. In addition to hard wiring provided by fast synaptic transmitter-releasing neurons and soft wiring contributed by peptidergic, aminergic and purinergic systems, electrical coupling may serve as the 'skeleton' of lateral processing, enabling important functions such

  9. Fatty acid transport protein 1 regulates retinoid metabolism and photoreceptor development in mouse retina.

    Directory of Open Access Journals (Sweden)

    Aurélie Cubizolle

    Full Text Available In retinal pigment epithelium (RPE, RPE65 catalyzes the isomerization of all-trans-retinyl fatty acid esters to 11-cis-retinol in the visual cycle and controls the rhodopsin regeneration rate. However, the mechanisms by which these processes are regulated are still unclear. Fatty Acid Transport Protein 1 (FATP1 is involved in fatty acid uptake and lipid metabolism in a variety of cell types. FATP1 co-localizes with RPE65 in RPE and inhibits its isomerase activity in vitro. Here, we further investigated the role of FATP1 in the visual cycle using transgenic mice that overexpress human FATP1 specifically in the RPE (hFATP1TG mice. The mice displayed no delay in the kinetics of regeneration of the visual chromophore 11-cis-retinal after photobleaching and had no defects in light sensitivity. However, the total retinoid content was higher in the hFATP1TG mice than in wild type mice, and the transgenic mice also displayed an age-related accumulation (up to 40% of all-trans-retinal and retinyl esters that was not observed in control mice. Consistent with these results, hFATP1TG mice were more susceptible to light-induced photoreceptor degeneration. hFATP1 overexpression also induced an ~3.5-fold increase in retinosome autofluorescence, as measured by two-photon microscopy. Interestingly, hFATP1TG retina contained ~25% more photoreceptor cells and ~35% longer outer segments than wild type mice, revealing a non-cell-autonomous effect of hFATP1 expressed in the RPE. These data are the first to show that FATP1-mediated fatty acid uptake in the RPE controls both retinoid metabolism in the outer retina and photoreceptor development.

  10. Spatial distribution of excitatory synapses on the dendrites of ganglion cells in the mouse retina.

    Directory of Open Access Journals (Sweden)

    Yin-Peng Chen

    Full Text Available Excitatory glutamatergic inputs from bipolar cells affect the physiological properties of ganglion cells in the mammalian retina. The spatial distribution of these excitatory synapses on the dendrites of retinal ganglion cells thus may shape their distinct functions. To visualize the spatial pattern of excitatory glutamatergic input into the ganglion cells in the mouse retina, particle-mediated gene transfer of plasmids expressing postsynaptic density 95-green fluorescent fusion protein (PSD95-GFP was used to label the excitatory synapses. Despite wide variation in the size and morphology of the retinal ganglion cells, the expression of PSD95 puncta was found to follow two general rules. Firstly, the PSD95 puncta are regularly spaced, at 1-2 µm intervals, along the dendrites, whereby the presence of an excitatory synapse creates an exclusion zone that rules out the presence of other glutamatergic synaptic inputs. Secondly, the spatial distribution of PSD95 puncta on the dendrites of diverse retinal ganglion cells are similar in that the number of excitatory synapses appears to be less on primary dendrites and to increase to a plateau on higher branch order dendrites. These observations suggest that synaptogenesis is spatially regulated along the dendritic segments and that the number of synaptic contacts is relatively constant beyond the primary dendrites. Interestingly, we also found that the linear puncta density is slightly higher in large cells than in small cells. This may suggest that retinal ganglion cells with a large dendritic field tend to show an increased connectivity of excitatory synapses that makes up for their reduced dendrite density. Mapping the spatial distribution pattern of the excitatory synapses on retinal ganglion cells thus provides explicit structural information that is essential for our understanding of how excitatory glutamatergic inputs shape neuronal responses.

  11. β-catenin/Wnt signaling controls progenitor fate in the developing and regenerating zebrafish retina

    Directory of Open Access Journals (Sweden)

    Meyers Jason R

    2012-08-01

    Full Text Available Abstract Background The zebrafish retina maintains two populations of stem cells: first, the germinal zone or ciliary marginal zone (CMZ contains multipotent retinal progenitors that add cells to the retinal periphery as the fish continue to grow; second, radial glia (Müller cells occasionally divide asymmetrically to generate committed progenitors that differentiate into rod photoreceptors, which are added interstitially throughout the retina with growth. Retinal injury stimulates Müller glia to dedifferentiate, re-enter the cell cycle, and generate multipotent retinal progenitors similar to those in the CMZ to replace missing neurons. The specific signals that maintain these two distinct populations of endogenous retinal stem cells are not understood. Results We used genetic and pharmacological manipulation of the β-catenin/Wnt signaling pathway to show that it is required to maintain proliferation in the CMZ and that hyperstimulation of β-catenin/Wnt signaling inhibits normal retinal differentiation and expands the population of proliferative retinal progenitors. To test whether similar effects occur during regeneration, we developed a method for making rapid, selective photoreceptor ablations in larval zebrafish with intense light. We found that dephosphorylated β-catenin accumulates in Müller glia as they re-enter the cell cycle following injury, but not in Müller glia that remain quiescent. Activation of Wnt signaling is required for regenerative proliferation, and hyperstimulation results in loss of Müller glia from the INL as all proliferative cells move into the ONL. Conclusions β-catenin/Wnt signaling is thus required for the maintenance of retinal progenitors during both initial development and lesion-induced regeneration, and is sufficient to prevent differentiation of those progenitors and maintain them in a proliferative state. This suggests that the β-catenin/Wnt cascade is part of the shared molecular circuitry that

  12. Efficient retina formation requires suppression of both Activin and BMP signaling pathways in pluripotent cells

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    Kimberly A. Wong

    2015-03-01

    Full Text Available Retina formation requires the correct spatiotemporal patterning of key regulatory factors. While it is known that repression of several signaling pathways lead to specification of retinal fates, addition of only Noggin, a known BMP antagonist, can convert pluripotent Xenopus laevis animal cap cells to functional retinal cells. The aim of this study is to determine the intracellular molecular events that occur during this conversion. Surprisingly, blocking BMP signaling alone failed to mimic Noggin treatment. Overexpressing Noggin in pluripotent cells resulted in a concentration-dependent suppression of both Smad1 and Smad2 phosphorylation, which act downstream of BMP and Activin signaling, respectively. This caused a decrease in downstream targets: endothelial marker, xk81, and mesodermal marker, xbra. We treated pluripotent cells with dominant-negative receptors or the chemical inhibitors, dorsomorphin and SB431542, which each target either the BMP or Activin signaling pathway. We determined the effect of these treatments on retina formation using the Animal Cap Transplant (ACT assay; in which treated pluripotent cells were transplanted into the eye field of host embryos. We found that inhibition of Activin signaling, in the presence of BMP signaling inhibition, promotes efficient retinal specification in Xenopus tissue, mimicking the affect of adding Noggin alone. In whole embryos, we found that the eye field marker, rax, expanded when adding both dominant-negative Smad1 and Smad2, as did treating the cells with both dorsomorphin and SB431542. Future studies could translate these findings to a mammalian culture assay, in order to more efficiently produce retinal cells in culture.

  13. Efficiency of RAFT-synthesized PDMAEMA in gene transfer to the retina.

    Science.gov (United States)

    Bitoque, Diogo B; Simão, Sónia; Oliveira, Ana V; Machado, Susana; Duran, Margarita R; Lopes, Eduardo; da Costa, Ana M Rosa; Silva, Gabriela A

    2017-01-01

    Gene therapy has long been heralded as the new hope to evolve from symptomatic care of genetic pathologies to a full cure. Recent successes in using gene therapy for treating several ocular and haematopoietic pathologies have shown the great potential of this approach that, in the early days, relied on the use of viral vectors, which were considered by many to be undesirable for human treatment. Therefore, there is considerable interest and effort in developing non-viral vectors, with efficiency close to that of viral vectors. The aim of this study was to develop suitable non-viral carriers for gene therapy to treat pathologies affecting the retina. In this study poly(2-(N,N-dimethylamino)ethyl methacrylate), PDMAEMA was synthesized by reversible addition-fragmentation chain transfer (RAFT) and the in vitro cytocompatibility and transfection efficiency of a range of polymer:DNA ratios evaluated using a retinal cell line; in vivo biocompatibility was evaluated by ocular injection in C57BL/6 mice. The results showed that through RAFT, it is possible to produce a defined-size polymer that is compatible with cell viability in vitro and capable of efficiently directing gene expression in a polymer-DNA ratio-dependent manner. When injected into the eyes of mice, these vectors induced a transient, mild inflammation, characteristic of the implantation of medical devices. These results form the basis of future studies where RAFT-synthesized PDMAEMA will be used to deliver gene expression systems to the retina of mouse models of retinal pathologies. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

  14. Biological effects of blocking blue and other visible light on the mouse retina.

    Science.gov (United States)

    Narimatsu, Toshio; Ozawa, Yoko; Miyake, Seiji; Kubota, Shunsuke; Yuki, Kenya; Nagai, Norihiro; Tsubota, Kazuo

    2014-08-01

    To elucidate the biological effects of blocking fluorescent light on the retina using specific blocking materials. Seven- to 8-week-old BALB/c mice were divided into three groups and placed in one of the three boxes: one blocked ultraviolet and violet wavelengths of light (violet blockade), one blocked ultraviolet, violet, blue and some other visible wavelengths (blue-plus blockade), and one allowed most visible light to pass through (control). They were then exposed to a white fluorescent lamp for 1 h at 5.65E-05 mW/cm(2) /s. After treatment, the electroretinogram, retinal outer nuclear layer thickness and retinal outer segment length were measured. In addition, retinal apoptotic cells were quantified by TdT-mediated dUTP nick-end labelling assay and c-Fos messenger RNA, and protein levels were measured by real-time reverse-transcription polymerase chain reaction and immunoblot analyses, respectively. The blue-plus blockade group retained a significantly better electroretinogram response following light exposure than the control or violet blockade groups. The blue-plus blockade group also exhibited greater outer nuclear layer thickness and greater outer-segment length, and fewer apoptotic cells after light exposure than the other groups. The c-Fos messenger RNA and protein levels were substantially reduced in the blue-plus blockade group and reduced to a lesser extent in the violet blockade group. The blockade of blue plus additional visible wavelengths of light was most effective in protecting the retina from light-induced damage. The blockade of violet light alone was also effective in reducing intracellular molecular responses, but these effects were not sufficient for attenuating retinal degeneration. © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  15. Electron Microscopic Changes of Rabbit Retina after Chromovitrectomy Using Combined Dyes (Experimental Study

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    B. M. Aznabaev

    2018-01-01

    Full Text Available Purpose: to evaluate on experimental model electron-microscopic changes of rabbit retina after staining of the posterior eye segmentwith combined dyes based on Trypan blue and Brilliant blue G for the assessment of their safety. Methods. The study was performed onChinchilla breed rabbits. Combined dyes based on Trypan blue and Brilliant blue were used: MembraneBlue-Dual (DORC, Netherlandsand “Staining solution for ophthalmic surgery” (JCS “Optimedservis”, Russia. Standard three-port vitrectomy technique was used. After vitreous removal dyes were injected in vitreous cavity and exposed for 10 seconds and then removed. The vitreous cavity was filled by a balanced salt solution. An electron-microscopic evaluation was performed on 5, 14 and 30 days after surgery. Eyes were enucleated in 20 minutes after animal was killed by air embolization. Intact eyes were used as a control, all samples were prepared in same сonditions. The damage of the retina architectonics and the presence of intracellular inclusions were evaluated. Results. The staged character of pathomorphological changes was revealed. On the 5th day moderate edema and hydropic dystrophy of neurons were registered. On the 14th day, there was no negative dynamics. On day 30, the signs of edema and dystrophy of neurons practically disappeared, which may indicate a fundamental reversibility of the registered changes. Conclusion. Investigated dyes for staining intraocular structures based on Trypan blue and Brilliant blue did not cause significant histomorphological changes and toxic effects on retinal cell structures. Detected electron microscopic changes were insignificant, had reversible character and could be mostly caused by a surgical injury.

  16. Response Properties of a Newly Identified Tristratified Narrow Field Amacrine Cell in the Mouse Retina.

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    G S Newkirk

    Full Text Available Amacrine cells were targeted for whole cell recording using two-photon fluorescence microscopy in a transgenic mouse line in which the promoter for dopamine receptor 2 drove expression of green fluorescent protein in a narrow field tristratified amacrine cell (TNAC that had not been studied previously. Light evoked a multiphasic response that was the sum of hyperpolarizing and depolarization synaptic inputs consistent with distinct dendritic ramifications in the off and on sublamina of the inner plexiform layer. The amplitude and waveform of the response, which consisted of an initial brief hyperpolarization at light onset followed by recovery to a plateau potential close to dark resting potential and a hyperpolarizing response at the light offset varied little over an intensity range from 0.4 to ~10^6 Rh*/rod/s. This suggests that the cell functions as a differentiator that generates an output signal (a transient reduction in inhibitory input to downstream retina neurons that is proportional to the derivative of light input independent of its intensity. The underlying circuitry appears to consist of rod and cone driven on and off bipolar cells that provide direct excitatory input to the cell as well as to GABAergic amacrine cells that are synaptically coupled to TNAC. Canonical reagents that blocked excitatory (glutamatergic and inhibitory (GABA and glycine synaptic transmission had effects on responses to scotopic stimuli consistent with the rod driven component of the proposed circuit. However, responses evoked by photopic stimuli were paradoxical and could not be interpreted on the basis of conventional thinking about the neuropharmacology of synaptic interactions in the retina.

  17. Osteochondritis Dissecans in Crioulo Foals (Case Report OSTEOCONDRITE DISSECANTE EM POTROS DA RAÇA CRIOULA

    Directory of Open Access Journals (Sweden)

    Márcio Nunes Correa

    2008-12-01

    Full Text Available The aim of this paper was to describe the manifestation of developmental orthopedic diseases, particularly Osteochondritis Dissecans (OCD, in Crioulo foals, considering the clinical sings, radiological study and the animal’s diet. Were evaluated three foals from Crioulo breed presenting volume increase in the knee, fore fetlock and hind fetlock joints. The foals were submitted to radiological examination of the affected joints, showing irregular images in the growing plates region and radiolucent areas in the distal portion of the radius e first phalanx, characterizing the presence of degenerative lesions of the articular cartilage.  The bromatological study of the pastures was made demonstrating imbalances in the calcium-phosphorus relation, being this one of the mains factors involved in the development of OCD lesions. The diagnosis was perform based on the clinical e radiological changes, besides the animal’s diet, age group and practiced exercise.

    KEY WORDS: Crioulo,  DOD, equine, osteochondritis dissecans, orthopedics. Este estudo teve como objetivo descrever a manifestação de distúrbios ortopédicos do desenvolvimento, particularmente a osteocondrite dissecante (OCD, em potros da raça Crioula, levando em consideração os sinais clínicos, estudo radiológico e a dieta dos animais. Avaliaram-se três potros da raça Crioula que apresentaram aumento de volume nas articulações radiocárpicas, metacarpofalangeanas e metatarsofalangeanas. Estes foram submetidos a exame radiológico das regiões afetadas, demonstrando áreas de irregularidade nas placas de crescimento e áreas radioluscentes na porção distal do rádio e primeira falange, caracterizando a presença de lesões degenerativas da cartilagem articular. Desenvolveu-se estudo bromatológico das pastagens, verificando-se desequilíbrios na relação cálcio–fósforo, sendo este um dos principais fatores envolvidos no desenvolvimento de lesões de OCD. O diagn

  18. Localisation of the Putative Magnetoreceptive Protein Cryptochrome 1b in the Retinae of Migratory Birds and Homing Pigeons.

    Directory of Open Access Journals (Sweden)

    Petra Bolte

    Full Text Available Cryptochromes are ubiquitously expressed in various animal tissues including the retina. Some cryptochromes are involved in regulating circadian activity. Cryptochrome proteins have also been suggested to mediate the primary mechanism in light-dependent magnetic compass orientation in birds. Cryptochrome 1b (Cry1b exhibits a unique carboxy terminus exclusively found in birds so far, which might be indicative for a specialised function. Cryptochrome 1a (Cry1a is so far the only cryptochrome protein that has been localised to specific cell types within the retina of migratory birds. Here we show that Cry1b, an alternative splice variant of Cry1a, is also expressed in the retina of migratory birds, but it is primarily located in other cell types than Cry1a. This could suggest different functions for the two splice products. Using diagnostic bird-specific antibodies (that allow for a precise discrimination between both proteins, we show that Cry1b protein is found in the retinae of migratory European robins (Erithacus rubecula, migratory Northern Wheatears (Oenanthe oenanthe and pigeons (Columba livia. In all three species, retinal Cry1b is localised in cell types which have been discussed as potentially well suited locations for magnetoreception: Cry1b is observed in the cytosol of ganglion cells, displaced ganglion cells, and in photoreceptor inner segments. The cytosolic rather than nucleic location of Cry1b in the retina reported here speaks against a circadian clock regulatory function of Cry1b and it allows for the possible involvement of Cry1b in a radical-pair-based magnetoreception mechanism.

  19. Pushing the limits of photoreception in twilight conditions: The rod-like cone retina of the deep-sea pearlsides

    KAUST Repository

    Busserolles, Fanny de

    2017-11-09

    Most vertebrates have a duplex retina comprising two photoreceptor types, rods for dim-light (scotopic) vision and cones for bright-light (photopic) and color vision. However, deep-sea fishes are only active in dim-light conditions; hence, most species have lost their cones in favor of a simplex retina composed exclusively of rods. Although the pearlsides, Maurolicus spp., have such a pure rod retina, their behavior is at odds with this simplex visual system. Contrary to other deep-sea fishes, pearlsides are mostly active during dusk and dawn close to the surface, where light levels are intermediate (twilight or mesopic) and require the use of both rod and cone photoreceptors. This study elucidates this paradox by demonstrating that the pearlside retina does not have rod photoreceptors only; instead, it is composed almost exclusively of transmuted cone photoreceptors. These transmuted cells combine the morphological characteristics of a rod photoreceptor with a cone opsin and a cone phototransduction cascade to form a unique photoreceptor type, a rod-like cone, specifically tuned to the light conditions of the pearlsides\\' habitat (blue-shifted light at mesopic intensities). Combining properties of both rods and cones into a single cell type, instead of using two photoreceptor types that do not function at their full potential under mesopic conditions, is likely to be the most efficient and economical solution to optimize visual performance. These results challenge the standing paradigm of the function and evolution of the vertebrate duplex retina and emphasize the need for a more comprehensive evaluation of visual systems in general.

  20. Distribution of FMRFamide-like immunoreactivity in the brain, retina and nervus terminalis of the sockeye salmon parr, Oncorhynchus nerka.

    Science.gov (United States)

    Ostholm, T; Ekström, P; Ebbesson, S O

    1990-09-01

    Neurons displaying FMRFamide(Phe - Met - Arg - Phe - NH2)-like immunoreactivity have recently been implicated in neural plasticity in salmon. We now extend these findings by describing the extent of the FMRF-like immunoreactive (FMRF-IR) system in the brain, retina and olfactory system of sockeye salmon parr using the indirect peroxidase anti-peroxidase technique. FMRF-IR perikarya were found in the periventricular hypothalamus, mesencephalic laminar nucleus, nucleus nervi terminalis and retina (presumed amacrine cells), and along the olfactory nerves. FMRF-IR fibers were distributed throughout the brain with highest densities in the ventral area of the telencephalon, in the medial forebrain bundle, and at the borders between layers III/IV and IV/V in the optic tectum. High densities of immunoreactive fibers were also observed in the area around the torus semicircularis, in the medial hypothalamus, median raphe, ventromedial tegmentum, and central gray. In the retina, immunopositive fibers were localized to the inner plexiform layer, but several fiber elements were also found in the outer plexiform layer. The olfactory system displayed FMRF-IR fibers in the epithelium and along the olfactory nerves. These findings differ from those reported in other species as follows: (i) FMRF-IR cells in the retina have not previously been reported in teleosts; (ii) the presence of FMRF-IR fibers in the outer plexiform layer of the retina is a new finding for any species; (iii) the occurrence of immunopositive cells in the mesencephalic laminar nucleus has to our knowledge not been demonstrated previously.

  1. Desenvolvimento de espessante alimentar com valor nutricional agregado, destinado ao manejo da disfagia

    Directory of Open Access Journals (Sweden)

    Carlos Henrique Pagno

    2014-04-01

    Full Text Available A disfagia se caracteriza por uma disfunção no processo de deglutição, sinal prevalente de doenças degenerativas como esclerose múltipla e doença de Parkinson. Alimentos de textura modificada e bebidas espessadas são tradicionalmente utilizados no auxílio para o tratamento clínico da disfagia. Assim, este trabalho objetivou desenvolver uma formulação de espessante alimentar com valor nutricional agregado, e avaliar sua eficiência em diferentes alimentos líquidos (leite integral, sucos de maçã, uva e laranja, sob diferentes condições de tempo de preparo (10 e 120 minutos e 24 horas e temperatura ambiente (25°C e refrigerada (10°C. A formulação foi composta de concentrado proteico de soro, mix de vitaminas e minerais e goma guar como agente espessante. Os valores obtidos para a viscosidade mostraram diferença estatisticamente significativa (P<0,05 entre os tempos de espessamento, sendo que as viscosidades no tempo de 10 minutos e após 24 horas variaram, respectivam