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Sample records for barrido heidelberg retina

  1. Heidelberg Retina Tomograph (HRT3) in Population-based Epidemiology : Normative Values and Criteria for Glaucomatous Optic Neuropathy

    NARCIS (Netherlands)

    Ramdas, Wishal D.; Wolfs, Roger C. W.; Hofman, Albert; de Jong, Paulus T. V. M.; Vingerling, Johannes R.; Jansonius, Nomdo M.

    2011-01-01

    Purpose: To establish normative values for Heidelberg Retina Tomograph (HRT3) variables and to develop HRT3-based criteria for glaucomatous optic neuropathy for epidemiological research in a white population. Methods: Consecutive participants in the Rotterdam Study were examined with HRT and simulta

  2. Optic nerve head analysis of superior segmental optic hypoplasia using Heidelberg retina tomography

    Directory of Open Access Journals (Sweden)

    Atsushi Miki

    2010-10-01

    Full Text Available Atsushi Miki1,2, Motohiro Shirakashi1, Kiyoshi Yaoeda1, Atsushi Fukushima1, Mineo Takagi1, Haruki Abe11Division of Ophthalmology and Visual Sciences, Niigata University Graduate School of Medical and Dental Sciences, Niigata, 2Department of Ophthalmology, Kawasaki Medical School, Okayama, JapanPurpose: To evaluate the optic disc characteristics of eyes with superior segmental optic hypoplasia (SSOH using the Heidelberg retina tomograph (HRT.Patients and methods: Thirteen eyes of 13 Japanese patients with SSOH were studied with the HRT (software version: 3.0. The group included six males and seven females, with a mean age of 34.7 years. Six optic disc parameters in the six sectors derived from the patients with SSOH were compared with those of 13 eyes of 13 normal controls. In addition, the diagnostic classification performance of the Frederick S Mikelberg (FSM discriminant function, glaucoma probability score (GPS, and Moorfields regression analysis (MRA were assessed.Results: When compared with normal subjects, many of the optic disc parameters were significantly altered in SSOH in the superior sectors. The area under the curve (AUC for the receiver operating characteristic was 0.932 for the rim area, 0.926 for the cup-to-disc area ratio, and 0.882 for the cup shape measure. Among the HRT parameters, the largest AUC (0.988 was found for the cup shape measure in the nasal superior segment. The proportion classified as outside normal limits by the FSM discriminant function was 92.3% (12 eyes. For GPS, six eyes (46.2% were classified as outside normal limits. For MRA, when borderline cases were considered test-negative or test-positive, 10 eyes (76.9% or 11 eyes (84.6% were classified as outside normal limits, respectively. The AUCs were 0.976 for the FSM discriminant function, 0.914 for the MRA overall classification, and 0.710 for the GPS overall classification.Conclusions: In eyes with SSOH, there is a significant thinning of the rim

  3. 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

    Directory of Open Access Journals (Sweden)

    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

  4. Ability of Optic Nerve Head Examination, Heidelberg Retina Tomograph’s Moorfield’s Regression Analysis, and Glaucoma Probability Score

    Directory of Open Access Journals (Sweden)

    F. Saenz-Frances

    2015-01-01

    Full Text Available Purpose. To study whether a corneal thickness segmentation model, consisting in a central circular zone of 1 mm radius centered at the corneal apex (zone I and five concentric rings of 1 mm width (moving outwards: zones II to VI, could boost the diagnostic accuracy of Heidelberg Retina Tomograph’s (HRT’s MRA and GPS. Material and Methods. Cross-sectional study. 121 healthy volunteers and 125 patients with primary open-angle glaucoma. Six binary multivariate logistic regression models were constructed (MOD-A1, MOD-A2, MOD-B1, MOD-B2, MOD-C1, and MOD-C2. The dependent variable was the presence of glaucoma. In MOD-A1, the predictor was the result (presence of glaucoma of the analysis of the stereophotography of the optic nerve head (ONH. In MOD-B1 and MOD-C1, the predictor was the result of the MRA and GPS, respectively. In MOD-B2 and MOD-C2, the predictors were the same along with corneal variables: central, overall, and zones I to VI thicknesses. This scheme was reproduced for model MOD-A2 (stereophotography along with corneal variables. Models were compared using the area under the receiver operator characteristic curve (AUC. Results. MOD-A1-AUC: 0.771; MOD-A2-AUC: 0.88; MOD-B1-AUC: 0.736; MOD-B2-AUC: 0.845; MOD-C1-AUC: 0.712; MOD-C2-AUC: 0.838. Conclusion. Corneal thickness variables enhance ONH assessment and HRT’s MRA and GPS diagnostic capacity.

  5. Corneal Segmentation Analysis Increases Glaucoma Diagnostic Ability of Optic Nerve Head Examination, Heidelberg Retina Tomograph's Moorfield's Regression Analysis, and Glaucoma Probability Score.

    Science.gov (United States)

    Saenz-Frances, F; Jañez, L; Berrozpe-Villabona, C; Borrego-Sanz, L; Morales-Fernández, L; Acebal-Montero, A; Mendez-Hernandez, C D; Martinez-de-la-Casa, J M; Santos-Bueso, E; Garcia-Sanchez, J; Garcia-Feijoo, J

    2015-01-01

    Purpose. To study whether a corneal thickness segmentation model, consisting in a central circular zone of 1 mm radius centered at the corneal apex (zone I) and five concentric rings of 1 mm width (moving outwards: zones II to VI), could boost the diagnostic accuracy of Heidelberg Retina Tomograph's (HRT's) MRA and GPS. Material and Methods. Cross-sectional study. 121 healthy volunteers and 125 patients with primary open-angle glaucoma. Six binary multivariate logistic regression models were constructed (MOD-A1, MOD-A2, MOD-B1, MOD-B2, MOD-C1, and MOD-C2). The dependent variable was the presence of glaucoma. In MOD-A1, the predictor was the result (presence of glaucoma) of the analysis of the stereophotography of the optic nerve head (ONH). In MOD-B1 and MOD-C1, the predictor was the result of the MRA and GPS, respectively. In MOD-B2 and MOD-C2, the predictors were the same along with corneal variables: central, overall, and zones I to VI thicknesses. This scheme was reproduced for model MOD-A2 (stereophotography along with corneal variables). Models were compared using the area under the receiver operator characteristic curve (AUC). Results. MOD-A1-AUC: 0.771; MOD-A2-AUC: 0.88; MOD-B1-AUC: 0.736; MOD-B2-AUC: 0.845; MOD-C1-AUC: 0.712; MOD-C2-AUC: 0.838. Conclusion. Corneal thickness variables enhance ONH assessment and HRT's MRA and GPS diagnostic capacity.

  6. Correlation Between Humphrey Visual Field, Optical Coherence Tomography and Heidelberg Retina Tomograph Parameters in Primary Open-Angle Glaucoma, Normal-Tension Glaucoma and Ocular Hypertension

    Directory of Open Access Journals (Sweden)

    Ziya Ayhan

    2011-06-01

    Full Text Available Purpose: To evaluate the correlation of Humphrey visual field (VF parameters (MD and PSD with Heidelberg Retina Tomograph (HRT 3 and Stratus optical coherence tomography (OCT parameters in patients with primary open-angle glaucoma (POAG, normal-tension glaucoma (NTG and ocular hypertension (OHT. Material and Method: Fifty-five eyes of 29 POAG patients, 32 eyes of 16 OHT patients and 26 eyes of 13 NTG patients were enrolled in the study prospectively. Humphrey visual field test as well as optic nerve head and retinal nerve fiber layer (RNFL thickness analysis with HRT 3 and Stratus OCT were performed in all patients; the measurements were repeated every 6 months. Results: The mean age of the patients was 66.4±10.0 years and the mean follow-up time was 22±2.2 months. In POAG and NTG groups, MD and PSD correlated with all analyzed parameters in HRT, except for the height variation contour (HVC. In POAG group, MD and PSD values correlated with all analyzed parameters in OCT, except for the rim area (RA. In NTG group, correlation was found between MD values and all parameters in OCT. In NTG group, PSD correlated with all parameters in OCT, except for the RNFL thickness. In OHT group, no correlation was found between MD, PSD values and HRT parameters. In OHT group, only RA values in OCT correlated with MD and PSD. In all groups, there was no statistically significant difference between the first and last examinations for MD and PSD values and for the mean RNFL thickness measured with OCT and HRT. Discussion: In our study, it was found that in POAG and NTG patients, there was a general correlation of Humphrey VF parameters with HRT 3 and Stratus OCT parameters. (Turk J Ophthalmol 2011; 41: 143-50

  7. The retina

    DEFF Research Database (Denmark)

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

    2003-01-01

    of oxidants by vascular endothelium and leukocytes. There is substantial evidence from animal and clinical studies for both impaired antioxidant defences and increased oxidative damage in the retinae of diabetic subjects that have been, in the case of animal studies, reversible with antioxidant......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 that certain regions of the retina are enriched in substrates for lipid peroxidation, may create an environment susceptible to oxidative damage. This may be more so in the diabetic retina, where hyperglycaemia may lead to elevated oxidant production by a number of mechanisms, including the production...

  8. The Heidelberg classification of renal cell tumours

    NARCIS (Netherlands)

    Kovacs, G; Akhtar, M; Beckwith, BJ; Bugert, P; Cooper, CS; Delahunt, B; Eble, JN; Fleming, S; Ljungberg, B; Medeiros, LJ; Moch, H; Reuter, VE; Ritz, E; Roos, G; Schmidt, D; Srigley, [No Value; Storkel, S; VandenBerg, E; Zbar, B

    1997-01-01

    This paper presents the conclusions of a workshop entitled 'Impact of Molecular Genetics on the Classification of Renal Cell Tumours', which was held in Heidelberg in October 1996, The focus on 'renal cell tumours' excludes any discussion of Wilms' tumour and its variants, or of tumours metastatic t

  9. Infrared retina

    Science.gov (United States)

    Krishna, Sanjay; Hayat, Majeed M.; Tyo, J. Scott; Jang, Woo-Yong

    2011-12-06

    Exemplary embodiments provide an infrared (IR) retinal system and method for making and using the IR retinal system. The IR retinal system can include adaptive sensor elements, whose properties including, e.g., spectral response, signal-to-noise ratio, polarization, or amplitude can be tailored at pixel level by changing the applied bias voltage across the detector. "Color" imagery can be obtained from the IR retinal system by using a single focal plane array. The IR sensor elements can be spectrally, spatially and temporally adaptive using quantum-confined transitions in nanoscale quantum dots. The IR sensor elements can be used as building blocks of an infrared retina, similar to cones of human retina, and can be designed to work in the long-wave infrared portion of the electromagnetic spectrum ranging from about 8 .mu.m to about 12 .mu.m as well as the mid-wave portion ranging from about 3 .mu.m to about 5 .mu.m.

  10. Fabricación reproducible de puntas de barrido para microscopios de efecto túnel

    OpenAIRE

    2008-01-01

    La fabricación reproducible de puntas de barrido para microscopios de efecto túnel es demostrada usando un método electroquímico. Las puntas son hechas a partir de alambre de tungsteno de 0.5 mm de diámetro. Controlando las condiciones de fabricación: la inmersión en la solución electrolítica, rangos de voltaje-corriente y duración del proceso se logra realizar puntas con relaciones de aspecto de 0.68 y radios de punta de 330 nm en el mejor caso./ Reproducible fabrication of Scanning Tunnelin...

  11. Sleeping Beauty. Revitalisation of the old indoor swimming pool Heidelberg; Sleeping Beauty. Revitalisierung des alten Hallenbads Heidelberg

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Jochen

    2010-07-01

    Since its closure before nearly 30 years due to safety aspects, the monument protected indoor swimming pool in Heidelberg (Federal Republic of Germany) dilapidated appreciably. Only after moving away of the local council from its demand of the wet use, an investor could be found.

  12. The Heidelberg Catechism: A 16th century quest for unity

    Directory of Open Access Journals (Sweden)

    Wim A. Dreyer

    2014-02-01

    Full Text Available In this contribution the view is presented that the Heidelberg Catechism should be regarded as an attempt to promote unity between 16th century reformers and churches in the Palatinate. This, to some extent, determined the content of the Catechism resulting in some controversial issues receiving less attention. This in turn not only made the Catechism acceptable to a wide spectrum of Reformed Christianity, but also resulted in a creative and unique contribution to Reformed theology, almost a ‘third option’. It was soon used in different Reformed territories as a confession and acclaimed for its clarity in formulating the basic Reformed faith. Today the Heidelberg Catechism is regarded as one of the most ‘ecumenical’ documents of the 16th century. As such, it still promotes unity amongst many Reformed churches, including those in South Africa.

  13. A refuge for inorganic chemistry: Bunsen's Heidelberg laboratory.

    Science.gov (United States)

    Nawa, Christine

    2014-05-01

    Immediately after its opening in 1855, Bunsen's Heidelberg laboratory became iconic as the most modern and best equipped laboratory in Europe. Although comparatively modest in size, the laboratory's progressive equipment made it a role model for new construction projects in Germany and beyond. In retrospect, it represents an intermediate stage of development between early teaching facilities, such as Liebig's laboratory in Giessen, and the new 'chemistry palaces' that came into existence with Wöhler's Göttingen laboratory of 1860. As a 'transition laboratory,' Bunsen's Heidelberg edifice is of particular historical interest. This paper explores the allocation of spaces to specific procedures and audiences within the laboratory, and the hierarchies and professional rites of passage embedded within it. On this basis, it argues that the laboratory in Heidelberg was tailored to Bunsen's needs in inorganic and physical chemistry and never aimed at a broad-scale representation of chemistry as a whole. On the contrary, it is an example of early specialisation within a chemical laboratory preceding the process of differentiation into chemical sub-disciplines. Finally, it is shown that the relatively small size of this laboratory, and the fact that after ca. 1860 no significant changes were made within the building, are inseparably connected to Bunsen's views on chemistry teaching.

  14. Fabricación reproducible de puntas de barrido para microscopios de efecto túnel

    Directory of Open Access Journals (Sweden)

    Rodrigo Bernal

    2008-05-01

    Full Text Available La fabricación reproducible de puntas de barrido para microscopios de efecto túnel es demostrada usando un método electroquímico. Las puntas son hechas a partir de alambre de tungsteno de 0.5 mm de diámetro. Controlando las condiciones de fabricación: la inmersión en la solución electrolítica, rangos de voltaje-corriente y duración del proceso se logra realizar puntas con relaciones de aspecto de 0.68 y radios de punta de 330 nm en el mejor caso./ Reproducible fabrication of Scanning Tunneling Microscope tips is carried out following an electrochemical procedure widely reported. Tips are made from 0.5 diameter tungsten wire. Controlling fabrication parameters (immersion in the electrochemical solution, current-voltage ranges, duration of the process, among others we achieve aspect ratios of 0.68 and tip radii of 330 nm in the best case.

  15. Progress and upgrading of the Heidelberg high current injector

    Indian Academy of Sciences (India)

    Roland Repnow

    2002-11-01

    A specialized rf-accelerator system HSI consisting of two RFQ’s and 8 rf seven-gap cavities was built for injection of high intensities of singly charged heavy ions into the Heidelberg heavy ion storage ring TSR. With different ion sources, this system now is used to deliver positive or negative, atomic and molecular ion beams with energies between 150 keV/a.m.u. and 5.3 MeV/a.m.u. final energy. For a future replacement of the MP-tandem-postaccelerator-system the new HSI-accelerator is to be equipped with an ECR source for high intensities of highly charged ions. An advanced commercial ECR source with a 18 GHz rf klystron and an adjustable extraction system for adaption of a wide range of injection energies has been commissioned at the manufacturer and is delivered. Test bench operation presently is in preparation at Heidelberg. A stripper section with an achromatic charge state selector is under construction between injector and postaccelerator. Other ion sources, e.g., for ultra cold $H^{+}_{3}$ molecular ion beams are under development.

  16. [Heidelberger study on psychoanalytic therapy of children and adolescents: methodology].

    Science.gov (United States)

    Fahrig, H

    1999-11-01

    In the representative studies published so far on the outcome of analytic child psychotherapy (Dührssen 1964; Fonagy and Target 1996) no techniques of treatment were mentioned. The following paper describes in detail the technique of treatment on which the Heidelberg Study "On the Therapeutic Outcome in Child and Adolescent Psychotherapy" is based, as it developed from 1975 to 1993 at the Heidelberg Institute for Child and Adolescent Psychotherapy. Starting from Piaget's findings that the cognitive faculties of a child up to the age of 11 completely differ from those of an adult and taking into consideration the cerebral information processing and "the intellect pervadet sensory" (Schopenhauer) it is demonstrated that children take their intrapsychic and interpersonal conflicts into analytic play therapy or into role play on analogous levels. Protected by a safe distance from being aware of their conflicts they will on the analogous levels understand, work through, partially solve their conflicts and make use of it in reality without conscious recognition. The term "analogous level" is defined and the manifold possibilities of therapeutic intervention on this level are demonstrated. The efficacy of therapeutic treatment on analogous levels is discussed.

  17. The Heidelberg CSR: Stored Ion Beams in a Cryogenic Environment

    Science.gov (United States)

    Wolf, A.; von Hahn, R.; Grieser, M.; Orlov, D. A.; Fadil, H.; Welsch, C. P.; Andrianarijaona, V.; Diehl, A.; Schröter, C. D.; Crespo López-Urrutia, J. R.; Rappaport, M.; Urbain, X.; Weber, T.; Mallinger, V.; Haberstroh, Ch.; Quack, H.; Schwalm, D.; Ullrich, J.; Zajfman, D.

    2006-03-01

    A cryogenic electrostatic ion storage ring CSR is under development at the Max-Planck Institute for Nuclear Physics in Heidelberg, Germany. Cooling of the ultrahigh vacuum chamber is envisaged to lead to extremely low pressures as demonstrated by cryogenic ion traps. The ring will apply electron cooling with electron beams of a few eV up to 200 eV. Through long storage times of 1000 s as well as through the low wall temperature, internal cooling of infrared-active molecular ions to their rotational ground state will be possible and their collisions with merged collinear beams of electrons and neutral atoms can be detected with high energy resolution. In addition storage of slow highly charged ions is foreseen. Using a fixed in-ring gas target and a reaction microscope, collisions of the stored ions at a spead of the order of the atomic unit can be kinematically reconstructed. The layout and the cryogenic concept are introduced.

  18. Retina and Omega-3

    OpenAIRE

    Giuseppe Querques; Raimondo Forte; Souied, Eric H.

    2011-01-01

    Over the last decade, several epidemiological studies based on food frequency questionnaires suggest that omega-3 polyunsaturated fatty acids could have a protective role in reducing the onset and progression of retinal diseases. The retina has a high concentration of omega-3, particularly DHA, which optimizes fluidity of photoreceptor membranes, retinal integrity, and visual function. Furthermore, many studies demonstrated that DHA has a protective, for example antiapoptotic, role in the ret...

  19. The infrared retina

    Science.gov (United States)

    Krishna, Sanjay

    2009-12-01

    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.

  20. The infrared retina

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, Sanjay, E-mail: skrishna@chtm.unm.ed [Center for High Technology Materials, Electrical and Computer Engineering Department University of New Mexico, 1313, Goddard Street SE, MSC04 2710 Albuquerque, NM, 87106 (United States)

    2009-12-07

    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.

  1. Helical tomotherapy. Experiences of the first 150 patients in Heidelberg

    Energy Technology Data Exchange (ETDEWEB)

    Sterzing, F.; Schubert, K.; Sroka-Perez, G.; Kalz, J.; Debus, J.; Herfarth, K. [Dept. of Radiation Oncology, Univ. of Heidelberg (Germany)

    2008-01-15

    Background and purpose: helical tomotherapy was introduced into clinical routine at the Department of Radiation Oncology, University Hospital of Heidelberg, Germany, in July 2006. This report is intended to describe the experience with the first 150 patients treated with helical tomotherapy. Patient selection, time effort, handling of daily image guidance with megavoltage (MV) CT, and quality of radiation plans shall be assessed. Patients and methods: between July 2006 and May 2007, 150 patients were treated with helical tomotherapy in the University Hospital of Heidelberg. Mean age was 60 years with a minimum of 30 years and a maximum of 85 years. 79 of these patients received radiotherapy as a part of multimodal treatment pre- or postoperatively, 17 patients received treatment as a combined radiochemotherapy. 76% were treated with curative intent. Radiotherapy sites were central nervous system (n = 7), head and neck (n = 28), thoracic (n = 37), abdominal (n = 58) and skeletal system (n = 20). Most common tumor entities were prostate cancer (n = 28), breast cancer (n = 17), gastrointestinal tumors (n = 19), pharyngeal carcinoma (n = 14), lymphoma (n = 13), metastatic disease (bone n = 14, liver n = 6, lung n = 4, lymph node n = 2), sarcoma (n = 8), malignant pleural mesothelioma (n = 5), ovarian cancer treated with whole abdominal irradiation (n = 4), lung cancer (n = 3), skin malignancies (n = 3), chordoma (n = 2), meningioma (n = 2), one ependymoma and one medulloblastoma treated with craniospinal axis irradiation (n = 2), and others (n = 4). Nine patients were treated with single-fraction radiosurgery, nine with image-guided spinal reirradiation, and twelve patients were treated at multiple targets simultaneously. A pretreatment MV-CT scan was performed in 98.2% of the 3,026 fractions applied. After matching with the kilovoltage planning CT, corrections for translations and rotation around longitudinal axis (roll) were done. Results: mean time on table was 24

  2. Die Berufung von Hermann Helmholtz an die Universität in Heidelberg

    OpenAIRE

    Werner, Franz

    2011-01-01

    Aus Briefen und unveröffentlichten Dokumenten können wir die langen und schwierigen Verhandlungen rekonstruieren, die zu Helmholtz' Berufung an die Universität Heidelberg und später zu seiner Berufung nach Berlin führten. Bereits 1851 hoffte Helmholtz auf eine Heidelberger Berufung. Jedoch wurde aus diesen Plänen nichts, als sein Fürsprecher J. Henle 1852 Heidelberg verließ. Erst 1857 nahm die Regierung des Großherzogs von Baden wieder Berufungsverhandlungen mit Helmholtz auf. Es war ha...

  3. "Heidelberg standard examination" and "Heidelberg standard procedures" - Development of faculty-wide standards for physical examination techniques and clinical procedures in undergraduate medical education.

    Science.gov (United States)

    Nikendei, C; Ganschow, P; Groener, J B; Huwendiek, S; Köchel, A; Köhl-Hackert, N; Pjontek, R; Rodrian, J; Scheibe, F; Stadler, A-K; Steiner, T; Stiepak, J; Tabatabai, J; Utz, A; Kadmon, M

    2016-01-01

    The competent physical examination of patients and the safe and professional implementation of clinical procedures constitute essential components of medical practice in nearly all areas of medicine. The central objective of the projects "Heidelberg standard examination" and "Heidelberg standard procedures", which were initiated by students, was to establish uniform interdisciplinary standards for physical examination and clinical procedures, and to distribute them in coordination with all clinical disciplines at the Heidelberg University Hospital. The presented project report illuminates the background of the initiative and its methodological implementation. Moreover, it describes the multimedia documentation in the form of pocketbooks and a multimedia internet-based platform, as well as the integration into the curriculum. The project presentation aims to provide orientation and action guidelines to facilitate similar processes in other faculties.

  4. Heidelberg University Library and its Special Subject Collection in Art History

    OpenAIRE

    2003-01-01

    The article provides a short survey of the history and the services of the Special Subject Collection "Medieval and Modern Art History (up to 1945)" / "Art Studies" at the Heidelberg University Library funded by the DFG (German Research Foundation).

  5. Multidrug-Resistant Salmonella Heidelberg Associated with Mechanically Separated Chicken at a Correctional Facility.

    Science.gov (United States)

    Taylor, Amanda L; Murphree, Rendi; Ingram, L Amanda; Garman, Katie; Solomon, Deborah; Coffey, Eric; Walker, Deborah; Rogers, Marsha; Marder, Ellyn; Bottomley, Marie; Woron, Amy; Thomas, Linda; Roberts, Sheri; Hardin, Henrietta; Arjmandi, Parvin; Green, Alice; Simmons, Latoya; Cornell, Allyson; Dunn, John

    2015-12-01

    We describe multidrug-resistant (MDR) Salmonella Heidelberg infections associated with mechanically separated chicken (MSC) served at a county correctional facility. Twenty-three inmates met the case definition. All reported diarrhea, 19 (83%) reported fever, 16 (70%) reported vomiting, 4 (17%) had fever ≥103°F, and 3 (13%) were hospitalized. A case-control study found no single food item significantly associated with illness. Salmonella Heidelberg with an indistinguishable pulsed-field gel electrophoresis pattern was isolated from nine stool specimens; two isolates displayed resistance to a total of five drug classes, including the third-generation cephalosporin, ceftriaxone. MDR Salmonella Heidelberg might have contributed to the severity of illness. Salmonella Heidelberg indistinguishable from the outbreak subtype was isolated from unopened MSC. The environmental health assessment identified cross-contamination through poor food-handling practices as a possible contributing factor. Proper hand-washing techniques and safe food-handling practices were reviewed with the kitchen supervisor.

  6. obtención de barridos láser 3D nivelados conn el robot móvil Andábata en movimiento

    OpenAIRE

    Martínez, Jorge L.; Morales, Jesús; Zafra, Manuel

    2016-01-01

    Este artículo describe la adquisición de barridos tridimensionales (3D) nivelados en el robot móvil Andábata sin necesidad de detener su movimiento. Para ello, la computadora de Andábata debe integrar cada uno de los rangos láser, adquiridos con unos determinados ángulos de cabeceo y guiñada, con la información odométrica y las medidas de inclinación del vehículo para producir coordenadas Cartesianas niveladas referenciadas al inicio de cada barrido. Todo ello se ha realizado bajo el sistema ...

  7. 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...

  8. [Research and development of artificial retina material].

    Science.gov (United States)

    Hu, Ning; Yang, Jun; Peng, Chenglin; Wang, Xing; Zhang, Sijie; Zhang, Ying; Zheng, Erxin

    2008-04-01

    The application of artificial retina was introduced. The principal characteristics of artificial retina material were reviewed in particular. Moreover, the recent research development and application prospect were discussed.

  9. Normierungsstudie des Heidelberger Vokaldifferenzierungstests für Viertklässler

    OpenAIRE

    Stuhrmann, NC; Plinkert, P; Brunner, M

    2010-01-01

    Hintergrund: Im deutschsprachigen Raum lagen bisher keine standardisierten Prüfverfahren zur Vokallängendifferenzierung innerhalb der Diagnostik der auditiven Wahrnehmung vor. Diese auditive Wahrnehmungsfunktion ist bedeutsam, da auf ihrer Grundlage die Rechtschreibregel der Konsonantenverdopplung beruht.Material und Methoden: In der Phoniatrie und Pädaudiologie der HNO-Klinik der Universität Heidelberg wurde der Heidelberger Vokaldifferenzierungstest (HVT) entwickelt. Anhand der vorliege...

  10. The Retina Algorithm

    CERN Document Server

    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.

  11. The proteome of human retina.

    Science.gov (United States)

    Zhang, Pingbo; Dufresne, Craig; Turner, Randi; Ferri, Sara; Venkatraman, Vidya; Karani, Rabia; Lutty, Gerard A; Van Eyk, Jennifer E; Semba, Richard D

    2015-02-01

    The retina is a delicate tissue that detects light, converts photochemical energy into neural signals, and transmits the signals to the visual cortex of the brain. A detailed protein inventory of the proteome of the normal human eye may provide a foundation for new investigations into both the physiology of the retina and the pathophysiology of retinal diseases. To provide an inventory, proteins were extracted from five retinas of normal eyes and fractionated using SDS-PAGE. After in-gel digestion, peptides were analyzed in duplicate using LC-MS/MS on an Orbitrap Elite mass spectrometer. A total of 3436 nonredundant proteins were identified in the human retina, including 20 unambiguous protein isoforms, of which eight have not previously been demonstrated to exist at the protein level. The proteins identified in the retina included most of the enzymes involved in the visual cycle and retinoid metabolism. One hundred and fifty-eight proteins that have been associated with age-related macular degeneration were identified in the retina. The MS proteome database of the human retina may serve as a valuable resource for future investigations of retinal biology and disease. All MS data have been deposited in the ProteomeXchange with identifier PXD001242 (http://proteomecentral.proteomexchange.org/dataset/PXD001242).

  12. Video 1 - Instrucciones Técnicas para el Manejo de un Microscopio Electroquímico de Barrido (SECM): Introducción - Partes del SECM

    OpenAIRE

    2015-01-01

    Video 1 de 14 correspondiente a las Instrucciones Técnicas para el Manejo de un Microscopio Electroquímico de Barrido (SECM). En este vídeo se hace una pequeña introducción acerca de los componentes de un SECM.

  13. Study of brain-derived neurotrophic factor gene transgenic neural stem cells in the rat retina

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xue-mei; YUAN Hui-ping; WU Dong-lai; ZHOU Xin-rong; SUN Da-wei; LI Hong-yi; SHAO Zheng-bo

    2009-01-01

    Background Neural stem cells (NSCs) transplantation and gene therapy have been widely investigated for treating the cerebullar and myelonic injuries, however, studies on the ophthalmology are rare. The aim of this study was to investigate the migration and differentiation of brain-derived neurotrophic factor (BDNF) gene transgenic NSCs transplanted into the normal rat retinas. Methods NSCs were cultured and purified in vitro and infected with recombinant retrovirus pLXSN-BDNF and pLXSN respectively, to obtain the BDNF overexpressed NSCs (BDNF-NSCs) and control cells (p-NSCs). The expression of BDNF genes in two transgenic NSCs and untreated NSCs were measured by fluorescent quantitative polymerase chain reaction (FQ-PCR) and enzyme-linked immunosorbent assay (ELISA). BDNF-NSCs and NSCs were infected with adeno-associated viruses-enhanced green fluorescent protein (AAV-EGFP) to track them in vivo and served as donor cells for transplantation into the subretinal space of normal rat retinas, phosphated buffer solution (PBS) served as pseudo transplantation for a negative control. Survival, migration, and differentiation of donor cells in host retinas were observed and analyzed with Heidelberg retina angiograph (HRA) and immunohistochemistry, respectively. Results NSCs were purified successfully by limiting dilution assay. The expression of BDNF gene in BDNF-NSCs was the highest among three groups both at mRNA level tested by FQ-PCR (P<0.05) and at protein level measured by ELISA (P<0.05), which showed that BDNF was overexpressed in BDNF-NSCs. The results of HRA demonstrated that graft cells could survive well and migrate into the host retinas, while the immunohistochemical analysis revealed that transplanted BDNF-NSCs differentiated into neuron more efficiently compared with the control NSCs 2 months after transplantation. Conclusions The seed cells of NSCs highly secreting BDNF were established. BDNF can promote NSCs to migrate and differentiate into neural cells in

  14. [Implantation of the artificial retina].

    Science.gov (United States)

    Yagi, T; Hayashida, Y

    1999-05-01

    In some degenerative retinal diseases, e.g., retinitis pigmentosa and age-related macular degeneration, the photoreceptors are destroyed to cause serious visual defects. Recent studies on blind human subjects revealed that a large number of ganglion cells remains intact and is capable of transmitting signals to the brain to evoke partial visual perception. This provided hope to compensate for the visual defects with retinal prostheses. The recent progress of microfabrication technique made it possible to implement the Vary Large Scale Integrated circuit, the artificial retina, which emulates a part of retinal function. The idea of implanting the artificial retina to the patients was proposed recently and experiments using animals have been put into practice. This article surveys the front line of the artificial retina implantation.

  15. Complete Genome Sequences of 17 Canadian Isolates of Salmonella enterica subsp. enterica Serovar Heidelberg from Human, Animal, and Food Sources.

    Science.gov (United States)

    Labbé, Geneviève; Ziebell, Kim; Bekal, Sadjia; Macdonald, Kimberley A; Parmley, E Jane; Agunos, Agnes; Desruisseau, Andrea; Daignault, Danielle; Slavic, Durda; Hoang, Linda; Ramsay, Danielle; Pollari, Frank; Robertson, James; Nash, John H E; Johnson, Roger P

    2016-01-01

    Salmonella enterica subsp. enterica serovar Heidelberg is a highly clonal serovar frequently associated with foodborne illness. To facilitate subtyping efforts, we report fully assembled genome sequences of 17 Canadian S Heidelberg isolates including six pairs of epidemiologically related strains. The plasmid sequences of eight isolates contain several drug resistance genes.

  16. Complete Genome Sequences of 17 Canadian Isolates of Salmonella enterica subsp. enterica Serovar Heidelberg from Human, Animal, and Food Sources

    Science.gov (United States)

    Labbé, Geneviève; Ziebell, Kim; Bekal, Sadjia; Parmley, E. Jane; Agunos, Agnes; Desruisseau, Andrea; Daignault, Danielle; Slavic, Durda; Hoang, Linda; Ramsay, Danielle; Pollari, Frank; Robertson, James; Nash, John H. E.

    2016-01-01

    Salmonella enterica subsp. enterica serovar Heidelberg is a highly clonal serovar frequently associated with foodborne illness. To facilitate subtyping efforts, we report fully assembled genome sequences of 17 Canadian S. Heidelberg isolates including six pairs of epidemiologically related strains. The plasmid sequences of eight isolates contain several drug resistance genes. PMID:27635008

  17. Observación del sistema poroso de rocas carbonatadas al microscopio electrónico de barrido

    Directory of Open Access Journals (Sweden)

    Alonso, F.

    1988-08-01

    Full Text Available The pore system of three carbonate rocks is studied through observation of resin and latex casts, under scanning electron microscope. The selected rocks -Hontoria and Seville limestones, and Boñar dolomite- have been broadly employed in the construction of outstanding monuments of the Spanish Historical Heritage. The degree of impregnation achieved by the epoxy resins, according to different procedures, is also checked by means of mercury injection porosimetry techniques. The observation of the pore casts displays, generally, the complexity of the pore systems of these rocks.Se estudia en este trabajo el sistema poroso de tres rocas carbonatadas, a partir de observaciones de moldes de resina y réplicas de látex al microscopio electrónico de barrido. Las rocas seleccionadas -calizas de Hontoria y Sevilla, y dolomía de Boñar- han sido ampliamente utilizadas en la construcción de importantes monumentos del Patrimonio Histórico Español. Se ha comprobado, asimismo, el grado de impregnación alcanzado por las resinas epoxídicas en diferentes procedimientos, a partir de técnicas de porosimetria de inyección de mercurio. Los resultados obtenidos ponen de manifiesto, en general, la complejidad de la estructura porosa de dichas rocas.

  18. ESTUDIO TERMOXIDATIVO NO ISOTERMICO POR CALORIMETRÍA DIFERENCIAL DE BARRIDO DE POLIETILENO DE BAJA DENSIDAD FORMULADO CON LIGNINA

    Directory of Open Access Journals (Sweden)

    Irama Piña-Saenz

    2012-01-01

    Full Text Available Se evaluó la capacidad antioxidante de la lignina (LLN en el polietileno de baja densidad (PEBD a través de un método no isotérmico empleando calorimetría diferencial de barrido (DSC. Las muestras bajo estudio, obtenidas de la formulación de PEBD con LLN, se sometieron a tratamientos térmicos a diferentes velocidades de calentamiento (β = 1, 3, 5, 7, 10, 15, 20 ° C/min, en presencia de oxígeno para favorecer la termo-oxidación del material. Se empleó un modelo cinético de degradación termoxidativa isoconversional, ajustada a la ecuación de Arrhenius, para determinar el factor de protección (PF de la lignina en la resina polimérica. Los resultados indican que bajo las formulaciones estudiadas, la lignina presenta una baja capacidad antioxidante en comparación con el Irganox1010. Sin embargo, en las formulaciones que contiene una mezcla de Irganox 1010 y lignina se observó un efecto sinergético en la capacidad antioxidativa de la lignina sobre el aditivo comercial.

  19. PROCEDIMIENTO DE CALIBRACIÓN EN TEMPERATURA Y FLUJO DE CALOR DE UN CALORÍMETRO DIFERENCIAL DE BARRIDO (DSC

    Directory of Open Access Journals (Sweden)

    Pablo E. Reynoso

    2016-01-01

    Full Text Available El calorímetro diferencial de barrido no es un dispositivo de medición absoluta, por lo que su utilización requiere indispensable mente una calibración. En esta contribución se presenta un procedimiento de calibración para el cual s e consideraron las temperaturas y calores de fusión aceptados en la literatura de 5 materiales puros . S e prepararon 6 muestras de dife rentes masas para cada material y s e sometió cada una de ellas a ci clos de calentamiento , desde temperatura ambiente hasta 50 ºC por encima de las temperaturas de fusión , utilizando 6 velocidades distintas por cada probeta. Luego, p ara determinar una relación de ajuste entre los datos experimentales obtenidos y los valores aceptados , se utilizó un método de regresión no lineal mediante un procedimiento matricial desarrollado en el entorno MATLAB . Los resultados obtenidos muestran una corrección con una desviación estándar de 1,2 ºC para el ajuste en temperatura y 2,1 5 J/g para el flujo de calor.

  20. Estudio de la superficie de limas de endodoncia sometidas a desinfección química mediante microscopia electrónica de barrido

    OpenAIRE

    Navarro Majó, G.; Mateos, M.; Navarro, J.L.; Canalda Sahli, Carlos

    1991-01-01

    Se observaron al microscopio electró nico de barrido 40 limas de endodoncia de acero inoxidable después de ser sometidas a 10 ciclos de desinfección de 10 minutos cada ciclo, sumergidas en diferentes desinfectantes químicos. No se observó corrosión en la superficie de las limas en las circunstancias en que se realizó ese estudio.

  1. Phenotypic and Genotypic Characterization of Animal-Source Salmonella Heidelberg Isolates

    Directory of Open Access Journals (Sweden)

    Kristin A. Clothier

    2016-01-01

    Full Text Available Salmonella enterica serotype Heidelberg (S. Heidelberg is frequently implicated in human foodborne Salmonella infections and often produces more severe clinical disease than other serotypes. Livestock and poultry products represent a potential risk for transmission to humans. The purpose of this study was to evaluate 49 S. Heidelberg veterinary isolates for exponential growth rate (EGR, PFGE pattern, and antimicrobial resistance to evaluate these parameters as mechanisms by which S. Heidelberg emerged as a virulent foodborne pathogen. Isolates were categorized by species of origin; clinical or environmental sources; and time frame of recovery. Growth rates were determined in nutrient media using serial dilutions and colony counts; PFGE was performed according to the CDC PulseNet protocol. Minimum inhibitory concentration and susceptibility determinations were performed against antimicrobials important in human medicine. Eighteen unique PFGE patterns were detected in the isolates tested. Antimicrobial resistance was significantly greater (P<0.05 for ten of 15 drugs in clinical over environmental isolates; for four drugs between the time frames; and for ten drugs between species of origin. The large genetic diversity present in isolates of this serotype may convey competitive advantages to this organism, while the presence of antimicrobial resistance represents a potential zoonotic risk via animal-source food products.

  2. Do artists see their retinas?

    NARCIS (Netherlands)

    Perdreau, F.A.G.; Cavanagh, P.

    2011-01-01

    Our perception starts with the image that falls on our retina and on this retinal image, distant objects are small and shadowed surfaces are dark. But this is not what we see. Visual constancies correct for distance so that, for example, a person approaching us does not appear to become a larger per

  3. Towards photovoltaic powered artificial retina

    OpenAIRE

    2011-01-01

    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. Peer Reviewed

  4. DNA sequence analysis of plasmids from multidrug resistant Salmonella enterica serotype Heidelberg isolates.

    Directory of Open Access Journals (Sweden)

    Jing Han

    Full Text Available Salmonella enterica serovar Heidelberg is among the most detected serovars in swine and poultry, ranks among the top five serotypes associated with human salmonellosis and is disproportionately associated with invasive infections and mortality in humans. Salmonella are known to carry plasmids associated with antimicrobial resistance and virulence. To identify plasmid-associated genes in multidrug resistant S. enterica serovar Heidelberg, antimicrobial resistance plasmids from five isolates were sequenced using the 454 LifeSciences pyrosequencing technology. Four of the isolates contained incompatibility group (Inc A/C multidrug resistance plasmids harboring at least eight antimicrobial resistance genes. Each of these strains also carried a second resistance plasmid including two IncFIB, an IncHI2 and a plasmid lacking an identified Inc group. The fifth isolate contained an IncI1 plasmid, encoding resistance to gentamicin, streptomycin and sulfonamides. Some of the IncA/C plasmids lacked the full concert of transfer genes and yet were able to be conjugally transferred, likely due to the transfer genes carried on the companion plasmids in the strains. Several non-IncA/C resistance plasmids also carried putative virulence genes. When the sequences were compared to previously sequenced plasmids, it was found that while all plasmids demonstrated some similarity to other plasmids, they were unique, often due to differences in mobile genetic elements in the plasmids. Our study suggests that Salmonella Heidelberg isolates harbor plasmids that co-select for antimicrobial resistance and virulence, along with genes that can mediate the transfer of plasmids within and among other bacterial isolates. Prevalence of such plasmids can complicate efforts to control the spread of S. enterica serovar Heidelberg in food animal and human populations.

  5. Ceftiofur Resistance in Salmonella enterica Serovar Heidelberg from Chicken Meat and Humans, Canada

    Science.gov (United States)

    Irwin, Rebecca; Finley, Rita; Ng, Lai King; Avery, Brent; Boerlin, Patrick; Bourgault, Anne-Marie; Cole, Linda; Daignault, Danielle; Desruisseau, Andrea; Demczuk, Walter; Hoang, Linda; Horsman, Greg B.; Ismail, Johanne; Jamieson, Frances; Maki, Anne; Pacagnella, Ana; Pillai, Dylan R.

    2010-01-01

    The Canadian Integrated Program for Antimicrobial Resistance Surveillance describes a strong correlation (r = 0.9, p<0.0001) between ceftiofur-resistant Salmonella enterica serovar Heidelberg isolated from retail chicken and incidence of ceftiofur-resistant Salmonella serovar Heidelberg infections in humans across Canada. In Québec, changes of ceftiofur resistance in chicken Salmonella Heidelberg and Escherichia coli isolates appear related to changing levels of ceftiofur use in hatcheries during the study period, from highest to lowest levels before and after a voluntary withdrawal, to increasing levels after reintroduction of use (62% to 7% to 20%, and 34% to 6% to 19%, respectively). These events provide evidence that ceftiofur use in chickens results in extended-spectrum cephalosporin resistance in bacteria from chicken and humans. To ensure the continued effectiveness of extended-spectrum cephalosporins for treating serious infections in humans, multidisciplinary efforts are needed to scrutinize and, where appropriate, limit use of ceftiofur in chicken production in Canada. PMID:20031042

  6. Molecular detection assay of five Salmonella serotypes of public interest: Typhimurium, Enteritidis, Newport, Heidelberg, and Hadar.

    Science.gov (United States)

    Bugarel, M; Tudor, A; Loneragan, G H; Nightingale, K K

    2017-03-01

    Foodborne illnesses due to Salmonella represent an important public-health concern worldwide. In the United States, a majority of Salmonella infections are associated with a small number of serotypes. Furthermore, some serotypes that are overrepresented among human disease are also associated with multi-drug resistance phenotypes. Rapid detection of serotypes of public-health concern might help reduce the burden of salmonellosis cases and limit exposure to multi-drug resistant Salmonella. We developed a two-step real-time PCR-based rapid method for the identification and detection of five Salmonella serotypes that are either overrepresented in human disease or frequently associated with multi-drug resistance, including serotypes Enteritidis, Typhimurium, Newport, Hadar, and Heidelberg. Two sets of four markers were developed to detect and differentiate the five serotypes. The first set of markers was developed as a screening step to detect the five serotypes; whereas, the second set was used to further distinguish serotypes Heidelberg, Newport and Hadar. The utilization of these markers on a two-step investigation strategy provides a diagnostic specificity of 97% for the detection of Typhimurium, Enteritidis, Heidelberg, Infantis, Newport and Hadar. The diagnostic sensitivity of the detection makers is >96%. The availability of this two-step rapid method will facilitate specific detection of Salmonella serotypes that contribute to a significant proportion of human disease and carry antimicrobial resistance.

  7. ASSESSMENT OF BENZOPHENANTHRIDINE AND PROTOPINE ALKALOIDS IN BROILER CHALLENGED AND NOT BY SALMONELLA HEIDELBERG

    Directory of Open Access Journals (Sweden)

    PFG Previato do Amaral

    Full Text Available ABSTRACT Salmonellosis is a globally important zoonosis, and Salmonella Heidelberg is one of the most prevalent serovars in poultry production worldwide, as well as in food poisoning cases. Antimicrobial drugs were previously widely used to face health challenges in animal production; however, since their ban as performance enhancers, many alternative strategies have been proposed. One of these strategies is the use of plant extracts, such as those containing the alkaloids benzophenanthridine and protopine. These compounds have antimicrobial, anti-inflammatory, immunomodulation, and nutritional effects. The objective of the present study was to evaluate the effects of the supply of a product containing benzophenanthridine and protopine (Sangrovit(rWS 100 g/1000 L of drinking water to broilers during different rearing periods 1-21, 1-6 and 6-21 days of age challenged or not with Salmonella Heidelberg at six days of age. There was no effect of the product on the performance, jejunal morphometry, cecal goblet cell counts, or control of Salmonella spp. in broilers challenged or not with Salmonella Heidelberg. However, the group receiving the alkaloids from 1 to 21 days of age, compared with the control group, presented a numerical difference of 28 points in productive efficiency index, which directly impacts live production cost of live broiler, representing savings of R$ 0.11/kg of meat produced.

  8. Ellipsometry and electronic microscopy of ashes swept of the Popocatepetl volcano; Elipsometria y microscopia electronica de barrido de las cenizas del volcan Popocatepetl

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, Aaron; Munoz, Rafel; Falcon, Nelson [Universidad de Carabobo, Valencia (Venezuela); Chavira, Enrique [Instituto Nacional de Astrofisica Optica y Electronica, Puebla (Mexico)

    2001-12-01

    The ellipsometry and the scanning electronic microscopy is applied to the study of the optic properties of Popocatepetl volcano ash in connection with the form, ruggedness and elemental chemical composition of the microparticles, also to argue about the relation with atmospheric conditions. [Spanish] Se aplica la eliposometria y la microscopia electronica de barrido al estudio de las propiedades opticas de las cenizas de volcan Popocatepetl en relacion con la forma, rugosidad y composicion quimica elemental de las microparticulas, destacandose su vinculacion con las condiciones de visibilidad.

  9. Desarrollo de un artefacto móvil que facilite el barrido y recolección de basuras en las calles y áreas extensas

    OpenAIRE

    Gutiérrez Suárez, Melissa; Múnera Restrepo, Santiago; Yepes Villa, Margaret

    2007-01-01

    Este proyecto de grado para el titulo de ingeniería de diseño de producto consiste en el desarrollo y diseño de una solución al problema de aseo y barrido de zonas urbanas y áreas extensas. El producto consiste en una maquina aspiradora que trabaja con un motor de gasolina de 5.5 caballos de fuerza, un ventilador de 1000 CFM y una capacidad de recolección de 45 litros por bolsa.

  10. Estudio morfológico del extremo apical inactivo de diversas limas mediante microscopía electrónica de barrido

    OpenAIRE

    Canalda Sahli, Carlos; Berástegui, Esther; Arroyo Bote, Sebastiana; Rais, A.; Brau Aguadé, Esteban

    1995-01-01

    Diversas firmas han manufacturado limas con el extremo apical inactivo para permitir efectuar la instrumentación de los conductos con una acción rotatoria. El objetivo de este estudio fue evaluar el extremo apical de estas limas (diámetros 30, 40 y 50) mediante microscopía electrónica de barrido, comparándolas con otras limas clásicas. Se observó en todas ellas un extremo apical sin espiras, a diferencia de las limas K convencionales.

  11. A Computational Framework for Realistic Retina Modeling.

    Science.gov (United States)

    Martínez-Cañada, Pablo; Morillas, Christian; Pino, Begoña; Ros, Eduardo; Pelayo, Francisco

    2016-11-01

    Computational simulations of the retina have led to valuable insights about the biophysics of its neuronal activity and processing principles. A great number of retina models have been proposed to reproduce the behavioral diversity of the different visual processing pathways. While many of these models share common computational stages, previous efforts have been more focused on fitting specific retina functions rather than generalizing them beyond a particular model. Here, we define a set of computational retinal microcircuits that can be used as basic building blocks for the modeling of different retina mechanisms. To validate the hypothesis that similar processing structures may be repeatedly found in different retina functions, we implemented a series of retina models simply by combining these computational retinal microcircuits. Accuracy of the retina models for capturing neural behavior was assessed by fitting published electrophysiological recordings that characterize some of the best-known phenomena observed in the retina: adaptation to the mean light intensity and temporal contrast, and differential motion sensitivity. The retinal microcircuits are part of a new software platform for efficient computational retina modeling from single-cell to large-scale levels. It includes an interface with spiking neural networks that allows simulation of the spiking response of ganglion cells and integration with models of higher visual areas.

  12. Retina

    Science.gov (United States)

    ... Foundations of Clinical Ophthalmology . 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013:vol 1;chap 19. Coleman ... EA, eds. Duane's Ophthalmology . 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013:vol 3;chap 3. Yanoff ...

  13. The Functional Architecture of the Retina.

    Science.gov (United States)

    Masland, Richard H.

    1986-01-01

    Examines research related to the retina's coding of visual input with emphasis on the organization of two kinds of ganglion cell receptive fields. Reviews current techniques for examining the shapes and arrangement in the retina of entire populations of nerve cells. (ML)

  14. Hypermutator Salmonella Heidelberg induces an early cell death in epithelial cells.

    Science.gov (United States)

    Le Gall-David, Sandrine; Zenbaa, Neila; Bouchard, Damien; Lavault, Marie-Thérèse; Bonnaure-Mallet, Martine; Jolivet-Gougeon, Anne; Bousarghin, Latifa

    2015-10-22

    We have previously described that a strain of Salmonella Heidelberg with a hypermutator phenotype, B182, adhered strongly to HeLa cells. In this work, we showed that this hypermutator Salmonella strain invaded HeLa epithelial cells and induced cytoskeleton alteration. Those changes lead to HeLa cell death which was characteristic of apoptosis. For the first time, we showed that this hypermutator strain induced apoptosis associated with the activation of caspases 2, 9 and 3. Complementation of B182 strain showed a decrease in cells death induction. In the presence of other Salmonella Heidelberg with a normomutator phenotype, such as WT and SL486, cell death and caspase 3 were undetectable. These results suggested that early apoptosis and caspase 3 activation were specific to B182. Besides, B182 induced LDH release and caspase 3 activation in CaCo-2 and HCT116 cells. Heat-treated B182 and diffusible products failed to induce this phenotype. Epithelial cells treatment with cytochalasin D caused the inhibition of B182 internalisation and caspase 3 activation. These results showed that this cell death required active S. Heidelberg B182 protein synthesis and bacterial internalisation. However sipB and sopB, usually involved in apoptosis induced by Salmonella were not overexpressed in B182, contrary to fimA and fliC. Comparative genome analysis showed numerous mutations as in rpoS which would be more investigated. The role of the hypermutator phenotype might be suspected to be implicated in these specific features. This result expands our knowledge about strong mutators frequently found in bacterial organisms isolated from clinical specimens.

  15. Assessment of the optic nerve head parameters using Heidelberg retinal tomography III in preterm children.

    Directory of Open Access Journals (Sweden)

    Salem Alshaarawi

    Full Text Available BACKGROUND: Variations in optic nerve head morphology and abnormal retinal vascular pattern have been described in preterm children using digital image analysis of fundus photograph, optical coherence tomograph and serial funduscopy. We aimed to compare the optic nerve head parameters in preterm and term Malay children using Heidelberg Retinal Tomograph III. DESIGN: A cross sectional study. METHODOLOGY/PRINCIPAL FINDINGS: Thirty-two preterm Malay children who were born at up to 32 weeks postconception, and 32 term Malay children aged 8-16 years old were recruited into this cross sectional study, which was conducted in the Hospital Universiti Sains Malaysia, Malaysia from January to December 2011. Their optic nerves were scanned and analyzed using a Heidelberg Retinal Tomography (HRT III (Heidelberg Engineering, Germany. Preterm children showed an increased rim volume (SD (0.56 (0.26 vs 0.44 (0.18 mm(3, respectively, smaller cup shape (SD (0.18 (0.07 vs 0.25 (0.06 mm, respectively, increased height variation contour (SD (0.44 (0.14 vs 0.35 (0.08 mm, respectively, and increased cup depth (SD (0.24 (0.11 vs 0.17 (0.05 mm(3, respectively when compared to their normal peers (p0.05 in our study. CONCLUSIONS/SIGNIFICANCE: Preterm children exhibit different characteristics of optic nerve head parameters with HRT III analysis. Increased cup depth in preterm children suggests a need for close observation and monitoring. It may raise suspicion of pediatric glaucoma when proper documentation of intraocular pressure and clinical funduscopy are unsuccessful in uncooperative children.

  16. Heidelberg Ion Therapy Center (HIT): Initial clinical experience in the first 80 patients

    Energy Technology Data Exchange (ETDEWEB)

    Combs, Stephanie E. (Univ. Hospital of Heidelberg, Dept. of Radiation Oncology, Heidelberg (Germany)), E-mail: Stephanie.Combs@med.uni-heidelberg.de; Ellerbrock, Malte; Haberer, Thomas (Heidelberger Ionenstrahl Therapiezentrum (HIT), Im Neuenheimer Feld 450, 69120 Heidelberg (Germany)) (and others)

    2010-10-15

    The Heidelberg Ion Therapy Center (HIT) started clinical operation in November 2009. In this report we present the first 80 patients treated with proton and carbon ion radiotherapy and describe patient selection, treatment planning and daily treatment for different indications. Patients and methods. Between November 15, 2009 and April 15, 2010, 80 patients were treated at the Heidelberg Ion Therapy Center (HIT) with carbon ion and proton radiotherapy. Main treated indications consisted of skull base chordoma (n = 9) and chondrosarcoma (n = 18), malignant salivary gland tumors (n=29), chordomas of the sacrum (n = 5), low grade glioma (n=3), primary and recurrent malignant astrocytoma and glioblastoma (n=7) and well as osteosarcoma (n = 3). Of these patients, four pediatric patients aged under 18 years were treated. Results. All patients were treated using the intensity-modulated rasterscanning technique. Seventy-six patients were treated with carbon ions (95%), and four patients were treated with protons. In all patients x-ray imaging was performed prior to each fraction. Treatment concepts were based on the initial experiences with carbon ion therapy at the Gesellschaft fuer Schwerionenforschung (GSI) including carbon-only treatments and carbon-boost treatments with photon-IMRT. The average time per fraction in the treatment room per patient was 29 minutes; for irradiation only, the mean time including all patients was 16 minutes. Position verification was performed prior to every treatment fraction with orthogonal x-ray imaging. Conclusion. Particle therapy could be included successfully into the clinical routine at the Dept. of Radiation Oncology in Heidelberg. Numerous clinical trials will subsequently be initiated to precisely define the role of proton and carbon ion radiotherapy in radiation oncology.

  17. Transmissible Plasmid Containing Salmonella enterica Heidelberg Isolates Modulate Cytokine Production During Early Stage of Interaction with Intestinal Epithelial Cells.

    Science.gov (United States)

    Gokulan, Kuppan; Khare, Sangeeta; Williams, Katherine; Foley, Steven L

    2016-08-01

    The variation in cytokine production during bacterial invasion of human intestinal epithelial cells (IECs) is a contributing factor for progression of the infection. A few Salmonella enterica Heidelberg strains isolated from poultry products harbor transmissible plasmids (TPs), including those that encode a type-IV secretion system. Earlier, we showed that these TPs are responsible for increased virulence during infection. This study examines the potential role of these TPs in cytokine production in IECs. This study showed that S. Heidelberg strains containing TPs (we refer as virulent strains) caused decreased interleukin (IL)-10 production in IECs after 1 h infection. The virulent strains induced a high level of tumor necrosis factor-α production under identical conditions. The virulent strains of S. Heidelberg also altered the production of IL-2, IL-17, and granulocyte macrophage colony-stimulating factor compared to an avirulent strain. As a part of infection, bacteria cross the epithelial barrier and encounter intestinal macrophages. Hence, we examined the cytotoxic mechanism of strains of S. Heidelberg in macrophages. Scanning electron microscopy showed cell necrosis occurs during the early stage of infection. In conclusion, virulent S. Heidelberg strains were able to modify the host cytokine profile during the early stages of infection and also caused necrosis in macrophages.

  18. Heidelberg standard examination” and “Heidelberg standard procedures” – Development of faculty-wide standards for physical examination techniques and clinical procedures in undergraduate medical education

    Directory of Open Access Journals (Sweden)

    Nikendei, C.

    2016-08-01

    Full Text Available The competent physical examination of patients and the safe and professional implementation of clinical procedures constitute essential components of medical practice in nearly all areas of medicine. The central objective of the projects “Heidelberg standard examination” and “Heidelberg standard procedures”, which were initiated by students, was to establish uniform interdisciplinary standards for physical examination and clinical procedures, and to distribute them in coordination with all clinical disciplines at the Heidelberg University Hospital. The presented project report illuminates the background of the initiative and its methodological implementation. Moreover, it describes the multimedia documentation in the form of pocketbooks and a multimedia internet-based platform, as well as the integration into the curriculum. The project presentation aims to provide orientation and action guidelines to facilitate similar processes in other faculties.

  19. Estudio Ultraestructural de Leptospira Biflexa Serovar Andamana cepa JNS al Microscopio Electrónico de Transmisión y Barrido

    Directory of Open Access Journals (Sweden)

    Sonia Macedo A

    2005-10-01

    Full Text Available Objetivos: Investigar la ultraestructura de Leptospira biflexa serovar Andamana cepa JNS, por la técnica de réplica metálica, cortes ultrafinos y tinción negativa al microscopio electrónico de transmisión (MET y barrido (MEB en alta y ultraalta resolución. Materiales y métodos: Cultivos en fase logarítmica 12-15x106 cel/mL del serovar Andamana cepa JNS, aislada de un paciente. Se aplicaron los métodos de tinción negativa, cortes ultrafinos y réplica metálica para la microscopía electrónica de transmisión. Para la microscopía electrónica de barrido se usaron las técnicas en alta y ultraalta resolución de muestras cubiertas con oro y platino. Resultados: Con el método de réplica metálica se definió la estructura externa en células individuales de Leptospira biflexa serovar Andamana al MET. Mediante la técnica de tinción negativa se observó la membrana externa formada por tres capas, los filamentos axiales, la membrana citoplasmática, el citoplasma granular con inclusiones electronodensas, las formaciones «globosas», la «estructura terminal», «apéndices terminales», además de las inclusiones permeables para los electrones, claramente definidas. La morfología clásica del microorganismo fue observada en cortes finos, y al microscopio electrónico de barrido. Conclusiones: Se reporta por primera vez la técnica de réplica metálica para determinar la morfología externa en células individuales de Leptospira biflexa serovar Andamana JNS, la cual ofrece resultados ventajosos en comparación con otros métodos. La ultraestructura, y las inclusiones permeables para electrones dentro del citoplasma a una magnificación de 120000x 20KV fueron nítidamente observadas por tinción negativa. La estructura helicoidal del microorganismo se comprobó al MEB.

  20. Role of dopamine in distal retina.

    Science.gov (United States)

    Popova, E

    2014-05-01

    Dopamine is the most abundant catecholamine in the vertebrate retina. Despite the description of retinal dopaminergic cells three decades ago, many aspects of their function in the retina remain unclear. There is no consensus among the authors about the stimulus conditions for dopamine release (darkness, steady or flickering light) as well as about its action upon the various types of retinal cells. Many contradictory results exist concerning the dopamine effect on the gross electrical activity of the retina [reflected in electroretinogram (ERG)] and the receptors involved in its action. This review summarized current knowledge about the types of the dopaminergic neurons and receptors in the retina as well as the effects of dopamine receptor agonists and antagonists on the light responses of photoreceptors, horizontal and bipolar cells in both nonmammalian and mammalian retina. Special focus of interest concerns their effects upon the diffuse ERG as a useful tool for assessment of the overall function of the distal retina. An attempt is made to reveal some differences between the dopamine actions upon the activity of the ON versus OFF channel in the distal retina. The author has included her own results demonstrating such differences.

  1. Glycogen metabolism in the rat retina.

    Science.gov (United States)

    Coffe, Víctor; Carbajal, Raymundo C; Salceda, Rocío

    2004-02-01

    It has been reported that glycogen levels in retina vary with retinal vascularization. However, the electrical activity of isolated retina depends on glucose supply, suggesting that it does not contain energetic reserves. We determined glycogen levels and pyruvate and lactate production under various conditions in isolated retina. Ex vivo retinas from light- and dark-adapted rats showed values of 44 +/- 0.3 and 19.5 +/- 0.4 nmol glucosyl residues/mg protein, respectively. The glycogen content of retinas from light-adapted animals was reduced by 50% when they were transferred to darkness. Glycogen levels were low in retinas incubated in glucose-free media and increased in the presence of glucose. The highest glycogen values were found in media containing 20 mm of glucose. A rapid increase in lactate production was observed in the presence of glucose. Surprisingly, glycogen levels were the lowest and lactate production was also very low in the presence of 30 mm glucose. Our results suggest that glycogen can be used as an immediate accessible energy reserve in retina. We speculate on the possibility that gluconeogenesis may play a protective role by removal of lactic acid.

  2. Nationwide outbreak of multidrug-resistant Salmonella Heidelberg infections associated with ground turkey: United States, 2011.

    Science.gov (United States)

    Routh, J A; Pringle, J; Mohr, M; Bidol, S; Arends, K; Adams-Cameron, M; Hancock, W T; Kissler, B; Rickert, R; Folster, J; Tolar, B; Bosch, S; Barton Behravesh, C; Williams, I T; Gieraltowski, L

    2015-11-01

    On 23 May 2011, CDC identified a multistate cluster of Salmonella Heidelberg infections and two multidrug-resistant (MDR) isolates from ground turkey retail samples with indistinguishable pulsed-field gel electrophoresis patterns. We defined cases as isolation of outbreak strains in persons with illness onset between 27 February 2011 and 10 November 2011. Investigators collected hypothesis-generating questionnaires and shopper-card information. Food samples from homes and retail outlets were collected and cultured. We identified 136 cases of S. Heidelberg infection in 34 states. Shopper-card information, leftover ground turkey from a patient's home containing the outbreak strain and identical antimicrobial resistance profiles of clinical and retail samples pointed to plant A as the source. On 3 August, plant A recalled 36 million pounds of ground turkey. This outbreak increased consumer interest in MDR Salmonella infections acquired through United States-produced poultry and played a vital role in strengthening food safety policies related to Salmonella and raw ground poultry.

  3. Dimensions of the foveal avascular zone using the Heidelberg retinal angiogram-2 in normal eyes

    Directory of Open Access Journals (Sweden)

    John Deepa

    2011-01-01

    Full Text Available Purpose: The purpose was to study the dimensions of the foveal avascular zone (FAZ using Heidelberg Retinal Angiogram-2 (HRA-2; Heidelberg Engineering GmBH, Dossenheim, Germany. Materials and Methods: An observational study of the FAZ area and circumference was done with fundus fluorescein angiography (FFA using HRA-2 in 31 normal individuals. The FAZ was studied using both contrast-adjusted and nonadjusted methods. Contrast adjustment was done to obtain better visualization of the finer capillaries around the fovea enabling more precise measurements of the FAZ in normal eyes. Results: The mean area of the FAZ calculated by the contrast-adjusted method was 0.2753 mm 2 (±0.074 and the mean circumference was 2.22 mm (±0.048. By the conventional method, the area and circumference of the FAZ were 0.6241 mm 2 (±0.177 and 3.23 mm (±0.454, respectively. Conclusion: The measurements of area and circumference of FAZ using contrast-adjusted methods were significantly smaller than the conventional method.

  4. Efecto del pH del agua de piscina en esmalte de dientes deciduos humanos. Estudio con microscopía electrónica de barrido

    OpenAIRE

    Cabrera Matta, Ailín R.; Facultad de Estomatología, Universidad Peruana Cayetano Heredia. Lima,; Kanashiro Irakawa, Carmen R.; Facultad de Estomatología, Universidad Peruana Cayetano Heredia. Lima,

    2014-01-01

    El objetivo de este trabajo fue evaluar in vitro el efecto de los niveles de pH ácidos del agua depiscina en la morfología de la superficie del esmalte de piezas deciduas. Se utilizaron 10 piezasdeciduas extraídas divididas en dos grupos. Un grupo fue expuesto al agua de piscina de pH 5.5 yel otro a pH 7, ambos por 20 horas. Se realizó una evaluación macroscópica y luego se metalizaronlas muestras para la evaluación con microscopía electrónica de barrido. Al aplicar la pruebaexacta de Fisher,...

  5. 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

  6. The Heidelberg High Current Injector A Versatile Injector for Storage Ring Experiments

    CERN Document Server

    Von Hahn, R; Repnow, R; Schwalm, D; Welsch, C P

    2004-01-01

    The High Current Injector (HCI) was designed and built as a dedicated injector for the Test Storage Ring in Heidelberg to deliver mainly singly charged Li- and Be-ions. After start for routine operation in 1999 the HCI delivered stable beams during the following years for about 50 % of the experiments with very high reliability. Due to the requirements from the experiment the HCI changed during that period from a machine for singly charged positive ions to an injector for a large variety of molecules as well as positively or negatively charged light ions. After successful commissioning of the custom built 18 GHz high power ECR-source at its present test location various modifications and additions were made in preparation of a possible conversion into an injector for highly charged heavy ions as a second phase. This paper gives an overview of the experience gained in the passed 5 years and presents the status of the upgrade of the HCI.

  7. International outbreak investigation of Salmonella Heidelberg associated with in-flight catering.

    LENUS (Irish Health Repository)

    Rebolledo, J

    2013-07-26

    SUMMARY Rapid and wide dispersal of passengers after flights makes investigation of flight-related outbreaks challenging. An outbreak of Salmonella Heidelberg was identified in a group of Irish travellers returning from Tanzania. Additional international cases sharing the same flight were identified. Our aim was to determine the source and potential vehicles of infection. Case-finding utilized information exchange using experts\\' communication networks and national surveillance systems. Demographic, clinical and food history information was collected. Twenty-five additional cases were identified from Ireland, The Netherlands, Norway, USA and Canada. We conducted a case-control study which indicated a significant association between illness and consumption of milk tart (OR 10·2) and an egg dish (OR 6) served on-board the flight. No food consumed before the flight was associated with illness. Cases from countries other than Ireland provided supplementary information that facilitated the identification of likely vehicles of infection. Timely, committed international collaboration is vital in such investigations.

  8. Enriched $^{76}$Ge the Heidelberg-Moscow double beta decay experiment

    CERN Document Server

    Zuber, K

    1995-01-01

    The recent results of the Heidelberg-Moscow double beta decay experiment are presented. After 8.6 kg\\cdoty of measuring time no signal is seen for the neutrinoless decay mode, therefore giving a half life limit of . This converts into a neutrino mass limit of < 0.7 eV (90\\% CL), showing that double beta decay entered the region below 1eV. For the 2 neutrino mode a half life of T_{1/2} = 1.53 \\cdot 10^{21} y is derived, meaning that more than 10000 double beta events are observed. This is the first high statistic observation. Limits on exotic decay modes and on dark matter particles are also presented.

  9. International outbreak investigation of Salmonella Heidelberg associated with in-flight catering.

    Science.gov (United States)

    Rebolledo, J; Garvey, P; Ryan, A; O'Donnell, J; Cormican, M; Jackson, S; Cloak, F; Cullen, L; Swaan, C M; Schimmer, B; Appels, R W; Nygard, K; Finley, R; Sreenivasan, N; Lenglet, A; Gossner, C; McKeown, P

    2014-04-01

    Rapid and wide dispersal of passengers after flights makes investigation of flight-related outbreaks challenging. An outbreak of Salmonella Heidelberg was identified in a group of Irish travellers returning from Tanzania. Additional international cases sharing the same flight were identified. Our aim was to determine the source and potential vehicles of infection. Case-finding utilized information exchange using experts' communication networks and national surveillance systems. Demographic, clinical and food history information was collected. Twenty-five additional cases were identified from Ireland, The Netherlands, Norway, USA and Canada. We conducted a case-control study which indicated a significant association between illness and consumption of milk tart (OR 10.2) and an egg dish (OR 6) served on-board the flight. No food consumed before the flight was associated with illness. Cases from countries other than Ireland provided supplementary information that facilitated the identification of likely vehicles of infection. Timely, committed international collaboration is vital in such investigations.

  10. Meeting Report: 3rd International Workshop on Insulin & Cancer Heidelberg, Germany, October 30-31, 2010

    Directory of Open Access Journals (Sweden)

    Chantelau Ernst

    2010-12-01

    Full Text Available Abstract The 3rd International Workshop on Insulin & Cancer was held on October 30-31, 2010 at the German Cancer Research Centre in Heidelberg/Germany. The topics followed-up the discussions of the previous workshops: possible differences in mitogenicity between natural insulin and genetically engineered insulin derivatives (insulin analogues, as shown by laboratory studies and epidemiologic studies alike; molecular studies on the links between metabolic and mitogenic effects of insulin, and of hyperinsulinaemia in particular; epidemiologic evidence of interferences between insulin and other hormones, particularly sex hormones, and obesity-associated cancer; the involvement of inflammatory cytokines produced by fat tissue in obesity-associated cancer; aspects of drug-design (binding drugs to albumin and, last but not least, detection and investigation of circulating cancer cells.

  11. Meeting report: 3rd international workshop on insulin & cancer heidelberg, Germany, october 30-31, 2010.

    Science.gov (United States)

    Chantelau, Ernst; Mayer, Doris

    2010-01-01

    The 3rd International Workshop on Insulin & Cancer was held on October 30-31, 2010 at the German Cancer Research Centre in Heidelberg/Germany. The topics followed-up the discussions of the previous workshops: possible differences in mitogenicity between natural insulin and genetically engineered insulin derivatives (insulin analogues), as shown by laboratory studies and epidemiologic studies alike; molecular studies on the links between metabolic and mitogenic effects of insulin, and of hyperinsulinaemia in particular; epidemiologic evidence of interferences between insulin and other hormones, particularly sex hormones, and obesity-associated cancer; the involvement of inflammatory cytokines produced by fat tissue in obesity-associated cancer; aspects of drug-design (binding drugs to albumin) and, last but not least, detection and investigation of circulating cancer cells.

  12. Commissioning of the Cryogenic Plant for the Cryogenic Storage Ring (CSR) at Heidelberg

    CERN Document Server

    von Hahn, R; Grieser, M; Haberstroh, C; Kaiser, D; Lange, M; Laux, F; Menk, S; Orlov, D A; Repnow, R; Sieber, T; Quack, H; Varju, J; Wolf A

    2009-01-01

    At the Max-Planck-Institute for Nuclear Physics in Heidelberg a next generation electrostatic storage ring for low velocity atomic and molecular ion beams is under construction. In contrast to existing electrostatic storage rings, the Cryogenic Storage Ring CSR will be cooled down to temperatures below 2 K. Thus acting as a large cryopump it will provide long storage times and, in addition, open a new field of quantum state controlled molecular physics due to a low heat radiation background from space-like environment. A concept for cooling the storage ring has been developed and is presently tested by means of a linear trap as a prototype with a length of 1/10 of the planned ring. A commercial refrigerator with 21 W at 2 K has been successfully commissioned and was connected to the prototype. This paper presents the status of the cryogenic plant after the commissioning and one year of operation.

  13. Recombination and Ionization Measurements at the Heidelberg Heavy Ion Storage Ring TSR

    Science.gov (United States)

    Hahn, M.; Lestinsky, M.; Novotný, O.; Savin, D. W.; Bernhardt, D.; Müller, A.; Schippers, S.; Krantz, C.; Grieser, M.; Repnow, R.; Wolf, A.

    2011-05-01

    Knowledge of the charge state distribution (CSD) of astrophysical plasmas is important for the interpretation of spectroscopic data. To accurately calculate CSDs, reliable rate coefficients are needed for dielectronic recombination (DR), which is the dominant electron-ion recombination mechanism for most ions, and for electron impact ionization (EII). We are carrying out DR and EII measurements of astrophysically important ions using the TSR storage ring at the Max-Plank-Institute for Nuclear Physics in Heidelberg, Germany. Storage ring measurements are largely free of the metastable contamination found in other experimental geometries, resulting in more unambiguous DR and EII reaction rate measurements. The measured data can be used in plasma modelling as well as for benchmarking theoretical atomic calculations.

  14. Cortical reorganization in recent-onset tinnitus patients by the Heidelberg Model of Music Therapy

    Directory of Open Access Journals (Sweden)

    Christoph Maria Krick

    2015-02-01

    Full Text Available Pathophysiology and treatment of tinnitus still are fields of intensive research. The neuroscientifically motivated Heidelberg Model of Music Therapy, previously developed by the German Center for Music Therapy Research, Heidelberg, Germany, was applied to explore its effects on individual distress and on brain structures. This therapy is a compact and fast application of nine consecutive 50-minutes sessions of individualized therapy implemented over one week. Clinical improvement and long-term effects over several years have previously been published. However the underlying neural basis of the therapy’s success has not yet been explored. In the current study, the therapy was applied to acute tinnitus patients (TG and healthy active controls (AC. Non-treated patients were also included as passive controls (PTC. As predicted, the therapeutic intervention led to a significant decrease of tinnitus-related distress in TG compared to PTC. Before and after the study week, high-resolution MRT scans were obtained for each subject. Assessment by repeated measures design for several groups (two-way ANOVA revealed structural gray matter (GM increase in TG compared to PTC, comprising clusters in precuneus, medial superior frontal areas, and in the auditory cortex. This pattern was further applied as mask for general GM changes as induced by the therapy week. The therapy-like procedure in AC also elicited similar GM increases in precuneus and frontal regions. Comparison between structural effects in TG versus AC was calculated within the mask for general GM changes to obtain specific effects in tinnitus patients, yielding GM increase in right Heschl's gyrus, right Rolandic operculum, and medial superior frontal regions. In line with recent findings on the crucial role of the auditory cortex in maintaining tinnitus-related distress, a causative relation between the therapy-related GM alterations in auditory areas and the long-lasting therapy effects can be

  15. 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.

  16. Towards a better understanding of forgiveness of sins in the first commentaries on the Heidelberg Catechism

    Directory of Open Access Journals (Sweden)

    Pieter C. Potgieter

    2013-06-01

    Full Text Available With regard to the issue of the forgiveness of sins in the Heidelberg Catechism, this paper shows that not only was there agreement and the same basic approach to issues of faith to be found in the commentaries of Ursinus and Olevianus, but also a valuable complementing of each other’s work. The influence of Calvin, with whom both of them have studied in Geneva, is obvious in their doctrinal approach. Whereas Ursinus tended more towards an academic correctness in his Explicationum Catecheticarum, Olevianus added a pastoral and spiritual dimension in his Vester Grundt. Although some theologians questioned the role of Olevianus in the compilation of the Heidelberg Catechism, recent research adequately shows that both of them were indeed involved, and were well-endowed with the necessary background for providing a further exposition of the Catechism. Both of them emphasise the unquestionable and sole merit of Jesus Christ, through his vicarious death on the cross, as the only ground for God’s gracious forgiveness of the sinner. It is God’s free gift, appropriated through faith and trust in the merit of Christ. Hierdie artikel toon aan dat daar, wat die vergifnis van sonde betref, nie net groot ooreenstemming en dieselfde basiese benadering ten opsigte van geloofskwessies in die kommentare van Ursinus en Olevianus op die Heidelbergse Kategismus is nie, maar dat daar ook ’n waardevolle wedersydse aanvulling van mekaar se werk is. Albei het by geleentheid in Genéve onder Calvyn gestudeer: sy invloed is onmiskenbaar in hulle leerstellige benaderings. In Ursinus se Explicationum Catecheticarum weeg die akademiese korrektheid swaarder, terwyl daar in Olevianus se Vester Grundt ook ‘n pastorale en spirituele dimensie bykom. Olevianus se betrokkenheid by die opstel van die Heidelbergse Kategismus is soms sterk bevraagteken, maar nuwe navorsing laat genoegsaam blyk dat albei teoloë inderdaad deel gehad het daaraan, en ook goed toegerus was met

  17. The joy at the Last Judgement according to the Heidelberg Catechism Question 52

    Directory of Open Access Journals (Sweden)

    Eberhard Busch

    2014-12-01

    Full Text Available In this contribution, the author reflects on Question 52 of the Heidelberg Catechism where it asks: ‘What comfort is it to you that Christ “shall come to judge the living and the dead”?’ The author points out possible sources from which this formulation stems, that is, Articles 86 and 87 in John Calvin’s Catechism from 1545. God is described as a compassionate judge. Even more: the One who is the last judge, was also judged and had paid for our sins. In a dialectical fashion we discover a God who is just, but also merciful. The Reformed tradition did not follow a dead-end where it is taught that God shows us grace instead of righteousness. Had God proceeded in this way, he would only mean things well, but he would not make them well. The realisation of God being just and merciful leads to joy and repentance. The contribution ends with a discussion of the final separation of the just and evil.

  18. Ionization and Recombination Measurements at the Heidelberg Heavy Ion Storage Ring TSR

    Science.gov (United States)

    Savin, D. W.; Hahn, M.; Lestinsky, M.; Novonty, O.; Bernhardt, D.; Mueller, A.; Schippers, S.; Krantz, C.; Wolf, A.

    2011-05-01

    Reliable ionization balance calculations are needed to analyze spectra from a wide range of cosmic sources including photoionized objects such as AGNs and X-ray binaries and electron ionized objects such as as stars, supernovae, galaxies, and clusters of galaxies. These theoretical charge state distributions (CSD) depend in turn upon the underlying atomic data. Of particular importance are reliable rate coefficients for dielectronic recombination (DR), which is the dominant electron-ion recombination recombination mechanism for most ions, and for electron impact ionization (EII). We are carrying out DR and EII measurements of astrophysically important ions using the heavy ion Test Storage Ring (TSR) at the Max-Plank-Institute for Nuclear Physics in Heidelberg, Germany. The storage ring measurements are largely free of the metastable contamination found in other experimental geometries. Storage ring measurements therefore result in more precise DR and EII reaction rate measurements. The measured rate coefficients can be used in modeling cosmic and laboratory plasmas as well as in the benchmarking of theoretical atomic calculations. Here we report results for selected recent DR and EII measurements.

  19. Low Energy Electron Cooling and Accelerator Physics for the Heidelberg CSR

    Science.gov (United States)

    Fadil, H.; Grieser, M.; von Hahn, R.; Orlov, D.; Schwalm, D.; Wolf, A.; Zajfman, D.

    2006-03-01

    The Cryogenic Storage Ring (CSR) is currently under construction at MPI-K in Heidelberg. The CSR is an electrostatic ring with a total circumference of about 34 m, straight section length of 2.5 m and will store ions in the 20 ˜ 300 keV energy range (E/Q). The cryogenic system in the CSR is expected to cool the inner vacuum chamber down to 2 K. The CSR will be equipped with an electron cooler which has also to serve as an electron target for high resolution recombination experiments. In this paper we present the results of numerical investigations of the CSR lattice with finite element calculations of the deflection and focusing elements of the ring. We also present a layout of the CSR electron cooler which will have to operate in low energy mode to cool 20 keV protons in the CSR, as well as numerical estimations of the cooling times to be expected with this device.

  20. A High Resolution Spectrograph for the 72 cm Waltz Telescope at Landessternwarte, Heidelberg

    CERN Document Server

    Tala, M; Grill, M; Harris, R J; Stürmer, J; Schwab, C; Gutcke, T; Reffert, S; Quirrenbach, A; Seifert, W; Mandel, H; Geuer, L; Schäffner, L; Thimm, G; Seemann, U; Tietz, J; Wagner, K

    2016-01-01

    The Waltz Spectrograph is a fiber-fed high-resolution \\'echelle spectrograph for the 72 cm Waltz Telescope at the Landessternwarte, Heidelberg. It uses a 31.6 lines/mm 63.5$^{\\circ}$ blaze angle \\'echelle grating in white-pupil configuration, providing a spectral resolving power of $R\\sim$65,000 covering the spectral range between 450$-$800\\,nm in one CCD exposure. A prism is used for cross-dispersion of \\'echelle orders. The spectrum is focused by a commercial apochromat onto a 2k$\\times$2k CCD detector with 13.5$\\mu$m per pixel. An exposure meter will be used to obtain precise photon-weighted midpoints of observations, which will be used in the computation of the barycentric corrections of measured radial velocities. A stabilized, newly designed iodine cell is employed for measuring radial velocities with high precision. Our goal is to reach a radial velocity precision of better than 5 m/s, providing an instrument with sufficient precision and sensitivity for the discovery of giant exoplanets. Here we descr...

  1. Lactate Transport and Receptor Actions in Retina

    DEFF Research Database (Denmark)

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

    2016-01-01

    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 ...

  2. Molecular characterization of Salmonella Paratyphi B dT+ and Salmonella Heidelberg from poultry and retail chicken meat in Colombia by pulsed-field gel electrophoresis

    Science.gov (United States)

    Salmonella Paratyphi B dT+ variant (also termed Salmonella Java) and Salmonella Heidelberg are human pathogens frequently isolated from poultry. As a step towards implementing the Colombian Integrated Program for Antimicrobial Resistant Surveillance (COIPARS), this study characterized molecular patt...

  3. Risks Involved in the Use of Enrofloxacin for Salmonella Enteritidis or Salmonella Heidelberg in Commercial Poultry.

    Science.gov (United States)

    Morales-Barrera, Eduardo; Calhoun, Nicole; Lobato-Tapia, Jose L; Lucca, Vivian; Prado-Rebolledo, Omar; Hernandez-Velasco, Xochitl; Merino-Guzman, Ruben; Petrone-García, Victor M; Latorre, Juan D; Mahaffey, Brittany D; Teague, Kyle D; Graham, Lucas E; Wolfenden, Amanda D; Baxter, Mikayla F A; Hargis, Billy M; Tellez, Guillermo

    2016-01-01

    The objectives of the present study were to evaluate the risks involved in the use of Enrofloxacin for Salmonella Enteritidis (SE) or Salmonella Heidelberg (SH) in commercial poultry and determine the effects of a probiotic as an antibiotic alternative. Two experiments were conducted to evaluate the risks involved in the use of Enrofloxacin for SE or SH in commercial poultry. Experiment 1 consisted of two trials. In each trial, chickens were assigned to one of three groups; control + SE challenged; Enrofloxacin 25 mg/kg + SE; and Enrofloxacin 50 mg/kg + SE. Chickens received Enrofloxacin in the drinking water from days 1 to 5 of age. On day 6, all groups received fresh water without any treatment. All chickens were orally gavaged with 10(7) cfu/chick of SE at 7 days of age and euthanized on 8 days of age. In Experiment 2, turkey poults were assigned to one of the three groups; control + SH; probiotic + SH; and Enrofloxacin 50 mg/kg + SH. Poults received probiotic or Enrofloxacin in the drinking water from days 1 to 5 of age. On day 6, poults received fresh water without any treatment. Poults were orally gavaged with 10(7) cfu/poult of SH at 7 days of age. Poults were weighed and humanely killed 24 h post-SH challenge to evaluate serum concentration of fluorescein isothiocyanate-dextran to evaluate intestinal permeability, metagenomics, and SH infection. In both trials of Experiment 1, chickens treated with Enrofloxacin were more susceptible to SE organ invasion and intestinal colonization when compared with control non-treated chickens (P salmonellae infections, and confirms that probiotics may be an effective tool in salmonellae infections.

  4. Effects of cold stress and Salmonella Heidelberg infection on bacterial load and immunity of chickens.

    Science.gov (United States)

    Borsoi, Anderlise; Quinteiro-Filho, Wanderley Moreno; Calefi, Atilio Sersun; Ferreira, Antonio José Piantino; Astolfi-Ferreira, Claudete Serrano; Florio, Jorge Camilo; Palermo-Neto, João

    2015-01-01

    We analysed the effects of cold stress (19 ± 1°C, 6 h /day, from the first to the seventh day of life) applied to specific pathogen free (SPF) chickens. On experimental Day 1 (ED1), chicks were divided into four groups: C (not infected and kept under thermoneutral condition); CS (not infected and cold stressed); PC (Salmonella Heidelberg (SH) infected and kept under thermoneutral condition) and PCS (SH infected and cold stressed). High concentrations of corticosterone were found in the cold stressed birds on ED7 and ED21, with a greater increase in birds of the PCS group. Stress or non-stressed SH-infected birds had high levels of norepinephrine on ED21. On ED21, an increased percentage and number of SH were found in birds of the PCS group. On ED7, a decrease in macrophages presenting MHCII, CD8(+) and CD8(+) γδ cells was observed in the chickens of the CS group. Decrease was observed in CD3(+) cells in the birds of the PCS group and increase in macrophages presenting MHCII cells and of the CD4(+)/CD8(+) ratio in chickens of the CS group on ED21. There was a decrease in CD8(+) γδ cells in birds of the CS group on ED21 and in the CD3(+) and CD8(+)cell numbers in chickens of the PCS group on ED21. Our results suggest that cold stress applied to chickens in the first 7 days of life increases both the hypothalamus pituitary adrenal axis and the sympathetic nervous system activities, leading to long-term immune cell dysfunction, thus allowing increased SH invasion and persistence within the birds' body.

  5. TRPM3 expression in mouse retina.

    Directory of Open Access Journals (Sweden)

    R Lane Brown

    Full Text Available Transient receptor potential (TRP channels constitute a large family of cation permeable ion channels that serve crucial functions in sensory systems by transducing environmental changes into cellular voltage and calcium signals. Within the retina, two closely related members of the melastatin TRP family, TRPM1 and TRPM3, are highly expressed. TRPM1 has been shown to be required for the depolarizing response to light of ON-bipolar cells, but the role of TRPM3 in the retina is unknown. Immunohistochemical staining of mouse retina with an antibody directed against the C-terminus of TRPM3 labeled the inner plexiform layer (IPL and a subset of cells in the ganglion cell layer. Within the IPL, TRPM3 immunofluorescence was markedly stronger in the OFF sublamina than in the ON sublamina. Electroretinogram recordings showed that the scotopic and photopic a- and b-waves of TRPM3(-/- mice are normal indicating that TRPM3 does not play a major role in visual processing in the outer retina. TRPM3 activity was measured by calcium imaging and patch-clamp recording of immunopurified retinal ganglion cells. Application of the TRPM3 agonist, pregnenolone sulfate (PS, stimulated increases in intracellular calcium in ~40% of cells from wild type and TRPM1(‑/‑ mice, and the PS-stimulated increases in calcium were blocked by co-application of mefenamic acid, a TRPM3 antagonist. No PS-stimulated changes in fluorescence were observed in ganglion cells from TRPM3(-/- mice. Similarly, PS-stimulated currents that could be blocked by mefenamic acid were recorded from wild type retinal ganglion cells but were absent in ganglion cells from TRPM3-/- mice.

  6. Silicon retina for optical tracking systems

    Science.gov (United States)

    Strohbehn, K.; Jenkins, R. E.; Sun, X.; Andreou, A. G.

    1993-01-01

    There are a host of position sensors, such as quadcells and CCD's, which are candidates for detecting optical position errors and providing error signals for a mirror positioning loop. We are developing a novel, very high bandwidth, biologically inspired position sensor for optical position tracking systems. We present recent test results and design issues for the use of biologically inspired silicon retinas for spaceborne optical position tracking systems.

  7. 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.

  8. Decalcified choroidal osteoma found in the retina

    Directory of Open Access Journals (Sweden)

    Yoshikawa T

    2012-11-01

    Full Text Available Tadanobu Yoshikawa, Kanji TakahashiDepartment of Ophthalmology, Kansai Medical University, Hirakata Hospital, Osaka, JapanAbstract: Choroidal osteoma is a benign tumor of the choroid. Herein, we report a rare case of decalcified choroidal osteoma found in the retina. A 27-year-old woman presented with visual loss. Her best-corrected visual acuity was 20/50 OS. Ophthalmoscopy of the left eye revealed a yellow-white calcified region accompanied by a decalcified region of four disc diameters in size. After 6 years, spectral-domain optical coherence tomography showed a tumor projected strongly upwards from the choroid and partially through the retina with serous retinal detachment, with both a lamellar appearance and mound-like area. The calcified region became more contractive than was observed on the first visit. Conversely, the decalcified region was wider than was observed on the first visit. Her best-corrected visual acuity was 20/400 OS. Choroidal osteoma was worsened by progression of decalcification. The decalcified choroidal osteoma resulted in poor visual acuity, and projected strongly upward from the choroid and into the retina.Keywords: osteoma, decalcification, choroidal osteoma

  9. 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.

  10. Fgf19 is required for zebrafish lens and retina development.

    Science.gov (United States)

    Nakayama, Yoshiaki; Miyake, Ayumi; Nakagawa, Yu; Mido, Tomotaka; Yoshikawa, Maya; Konishi, Morichika; Itoh, Nobuyuki

    2008-01-15

    Fgf signaling plays crucial roles in morphogenesis. Fgf19 is required for zebrafish forebrain development. Here, we examined the roles of Fgf19 in the formation of the lens and retina in zebrafish. Knockdown of Fgf19 caused a size reduction of the lens and the retina, failure of closure of the choroids fissure, and a progressive expansion of the retinal tissue to the midline of the forebrain. Fgf19 expressed in the nasal retina and lens was involved in cell survival but not cell proliferation during embryonic lens and retina development. Fgf19 was essential for the differentiation of lens fiber cells in the lens but not for the neuronal differentiation and lamination in the retina. Loss of nasal fate in the retina caused by the knockdown of Fgf19, expansion of nasal fate in the retina caused by the overexpression of Fgf19 and eye transplantation indicated that Fgf19 in the retina was crucial for the nasal-temporal patterning of the retina that is critical for the guidance of retinal ganglion cell axons. Knockdown of Fgf19 also caused incorrect axon pathfinding. The present findings indicate that Fgf19 positively regulates the patterning and growth of the retina, and the differentiation and growth of the lens in zebrafish.

  11. Effect of diabetes on glycogen metabolism in rat retina.

    Science.gov (United States)

    Sánchez-Chávez, Gustavo; Hernández-Berrones, Jethro; Luna-Ulloa, Luis Bernardo; Coffe, Víctor; Salceda, Rocío

    2008-07-01

    Glucose is the main fuel for energy metabolism in retina. The regulatory mechanisms that maintain glucose homeostasis in retina could include hormonal action. Retinopathy is one of the chemical manifestations of long-standing diabetes mellitus. In order to better understand the effect of hyperglycemia in retina, we studied glycogen content as well as glycogen synthase and phosphorylase activities in both normal and streptozotocin-induced diabetic rat retina and compared them with other tissues. Glycogen levels in normal rat retina are low (46 +/- 4.0 nmol glucosyl residues/mg protein). However, high specific activity of glycogen synthase was found in retina, indicating a substantial capacity for glycogen synthesis. In diabetic rats, glycogen synthase activity increased between 50% and 100% in retina, brain cortex and liver of diabetic rats, but only retina exhibited an increase in glycogen content. Although, total and phosphorylated glycogen synthase levels were similar in normal and diabetic retina, activation of glycogen synthase by glucose-6-P was remarkable increased. Glycogen phosphorylase activity decreased 50% in the liver of diabetic animals; it was not modified in the other tissues examined. We conclude that the increase in glycogen levels in diabetic retina was due to alterations in glycogen synthase regulation.

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

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    Jessica M Skeie

    Full Text Available PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

  13. Risks involved in the use of Enrofloxacin for Salmonella Enteritidis or Salmonella Heidelberg in commercial poultry

    Directory of Open Access Journals (Sweden)

    Eduardo Morales-Barrera

    2016-08-01

    Full Text Available The objectives of the present study were to evaluate the risks involved in the use of Enrofloxacin for Salmonella Enteritidis (SE or Salmonella Heidelberg (SH in commercial poultry and determine the effects of a probiotic as an antibiotic alternative. Two experiments were conducted to evaluate the risks involved in the use of Enrofloxacin for SE or SH in commercial poultry. Exp 1 consisted of 2 trials. In each trial, chickens were assigned to one of three groups; control + SE challenged; Enrofloxacin 25 mg/kg + SE; Enrofloxacin 50 mg/kg + SE. Chickens received Enrofloxacin in the drinking water from days 1 to 5 of age. On day 6, all groups received fresh water without any treatment. All chickens were orally gavaged with 107 cfu/chick of SE at 7 days of age and euthanized on 8 days of age. In Exp 2, turkey poults were assigned to one of the three groups; control + SH; probiotic + SH; Enrofloxacin 50 mg/kg + SH. Poults received probiotic or Enrofloxacin in the drinking water from days 1 to 5 of age. On day 6, poults received fresh water without any treatment. Poults were orally gavaged with 107 cfu/poult of SH at 7 days of age. Poults were weighted and humanely killed 24 h post-SH challenge to evaluate serum concentration of FITC-D to evaluate intestinal permeability, metagenomics and SH infection. In both trials of Exp 1, chickens treated with Enrofloxacin were more susceptible to SE organ invasion and intestinal colonization when compared with control non-treated chickens (P < 0.05. In Exp 2, poults treated with 50 mg/kg of Enrofloxacin showed an increase in body weight, however, this group also showed an increase in SH susceptibility, intestinal permeability and lower proportion of Firmicutes and Bacteroidetes, but with control group had the highest proportion of Proteobacteria. In contrast, poults that received the probiotic had the highest proportion of Firmicutes and Bacteroidetes, but lowest Proteobacteria. The results of the present study

  14. Risks Involved in the Use of Enrofloxacin for Salmonella Enteritidis or Salmonella Heidelberg in Commercial Poultry

    Science.gov (United States)

    Morales-Barrera, Eduardo; Calhoun, Nicole; Lobato-Tapia, Jose L.; Lucca, Vivian; Prado-Rebolledo, Omar; Hernandez-Velasco, Xochitl; Merino-Guzman, Ruben; Petrone-García, Victor M.; Latorre, Juan D.; Mahaffey, Brittany D.; Teague, Kyle D.; Graham, Lucas E.; Wolfenden, Amanda D.; Baxter, Mikayla F. A.; Hargis, Billy M.; Tellez, Guillermo

    2016-01-01

    The objectives of the present study were to evaluate the risks involved in the use of Enrofloxacin for Salmonella Enteritidis (SE) or Salmonella Heidelberg (SH) in commercial poultry and determine the effects of a probiotic as an antibiotic alternative. Two experiments were conducted to evaluate the risks involved in the use of Enrofloxacin for SE or SH in commercial poultry. Experiment 1 consisted of two trials. In each trial, chickens were assigned to one of three groups; control + SE challenged; Enrofloxacin 25 mg/kg + SE; and Enrofloxacin 50 mg/kg + SE. Chickens received Enrofloxacin in the drinking water from days 1 to 5 of age. On day 6, all groups received fresh water without any treatment. All chickens were orally gavaged with 107 cfu/chick of SE at 7 days of age and euthanized on 8 days of age. In Experiment 2, turkey poults were assigned to one of the three groups; control + SH; probiotic + SH; and Enrofloxacin 50 mg/kg + SH. Poults received probiotic or Enrofloxacin in the drinking water from days 1 to 5 of age. On day 6, poults received fresh water without any treatment. Poults were orally gavaged with 107 cfu/poult of SH at 7 days of age. Poults were weighed and humanely killed 24 h post-SH challenge to evaluate serum concentration of fluorescein isothiocyanate-dextran to evaluate intestinal permeability, metagenomics, and SH infection. In both trials of Experiment 1, chickens treated with Enrofloxacin were more susceptible to SE organ invasion and intestinal colonization when compared with control non-treated chickens (P < 0.05). In Experiment 2, poults treated with 50 mg/kg of Enrofloxacin showed an increase in body weight, however, this group also showed an increase in SH susceptibility, intestinal permeability, and lower proportion of Firmicutes and Bacteroidetes, but with control group had the highest proportion of Proteobacteria. By contrast, poults that received the probiotic had the highest

  15. Expression and functions of ASIC1 in the zebrafish retina.

    Science.gov (United States)

    Liu, Sha; Wang, Mei-Xia; Mao, Cheng-Jie; Cheng, Xiao-Yu; Wang, Chen-Tao; Huang, Jian; Zhong, Zhao-Min; Hu, Wei-Dong; Wang, Fen; Hu, Li-Fang; Wang, Han; Liu, Chun-Feng

    2014-12-12

    It has been demonstrated that acid sensing ionic channels (ASICs) are present in the central and peripheral nervous system of mammals, including the retina. However, it remains unclear whether the zebrafish retina also expresses ASICs. In the present study, the expression and distribution of zasic1 were examined in the retina of zebrafish. Both zasic1 mRNA and protein expressions were detected in the adult zebrafish retina. A wide distribution of ASIC1 in zebrafish retina was confirmed using whole mount in situ hybridization and immunohistochemistry study. Acidosis-induced currents in the isolated retinal ganglion cells (RGCs) were also recorded using whole cell patch clamping. Moreover, blockade of ASICs channel significantly reduced the locomotion of larval zebrafish in response to light exposure. In sum, our data demonstrate the presence of ASIC1 and its possible functional relevance in the retina of zebrafish.

  16. THE GENE EXPRESSION OF BDNF IN NORMAL RABBIT RETINA

    Institute of Scientific and Technical Information of China (English)

    王建明; 胡海涛; 马东亮; 孙乃学; 赵世平; 冯海晓

    2004-01-01

    Objective To investigate the distribution of brain-derived neurotrophic factor(BDNF) protein in the rabbit retina. Methods Immune response material in the retina was observed using BDNF antibody by the method of immunohistochemistry. Results BDNF gene expression was mainly found in the RGCs, also in innernuclei cells and outernuclei cells in rabbit retina. Conclusion RGC is not only the target cell of BDNF, but also express the BDNF protein. BDNF from multi-sources participates in the regulation of RGCs.

  17. Análisis por microscopía electroquímica de barrido de superficies electroactivas y desarrollo-caracterización de electrodos basados en un tejido de fibra de carbono

    OpenAIRE

    2014-01-01

    Una parte importante del trabajo desarrollado en la presente tesis está basado en la puesta a punto y aplicación de la técnica de la microscopía electroquímica de barrido (SECM). Con esta técnica se han caracterizado electroquímicamente superficies sobre las que se han sintetizado una serie de materiales electroactivos desarrollados por nuestro grupo de investigación. Dichos materiales se sintetizan sobre diferentes substratos con el fin de disponer de electrodos de trabajo con aplicación en ...

  18. From reformation to counter-reformation to further reformation: A picture of the anti-Roman background of the Heidelberg Catechism

    Directory of Open Access Journals (Sweden)

    Erik van Alten

    2013-08-01

    Full Text Available The anti-Roman sentiment of the Heidelberg Catechism is well-documented. In its contents the Catechism often seeks to combat Roman doctrine. However, this anti-Roman sentiment did not have its origin from textbooks and it was not merely an academic exercise. It was first and foremost a reaction to the ecclesiastical context of that time. At the same time that Elector Frederick III commissioned the writing of the Heidelberg Catechism, the Council of Trent was meeting on the other side of the Alpine mountains. Remarkably, this meeting had only recently decided to write a catechism of its own. It is very likely that the decision-makers in Heidelberg were aware of what was happening in Trent, and reacted accordingly. Underlying the decision to commission and write the Heidelberg Catechism was the acknowledgment of the importance of catechetical teaching. In several documents, which are closely related to the Heidelberg Catechism, the importance of catechetical teaching is highlighted. Interestingly, however, these documents also contrast the reformed principal of catechetical teaching with the Roman sacrament of confirmation. Whereas catechetical teaching leads children on the way from their baptism to the Lord’s Supper, the sacrament of confirmation takes away the urgency for any form of catechetical teaching.

  19. Artificial Retina Project: Electromagnetic and Thermal Effects

    Energy Technology Data Exchange (ETDEWEB)

    Lazzi, Gianluca

    2014-08-29

    This award supported the investigation on electromagnetic and thermal effects associated with the artificial retina, designed in collaboration with national laboratories, universities, and private companies. Our work over the two years of support under this award has focused mainly on 1) Design of new telemetry coils for optimal power and data transfer between the implant and the external device while achieving a significant size reduction with respect to currently used coils; 2) feasibility study of the virtual electrode configuration 3) study the effect of pulse shape and duration on the stimulation efficacy.

  20. A hermeneutical reflection on the resurrection of Jesus Christ in question and answer 45 of the Heidelberg Catechism

    Directory of Open Access Journals (Sweden)

    Kobus Labuschagne

    2013-06-01

    Full Text Available This article is an attempt to elaborate hermeneutically on the different historical contexts, related the one to the other and to the centre point of the resurrection of Jesus Christ, in question and answer 45 of the Heidelberg Catechism. The aim is not only to find the true meaning that the Heidelberg Catechism intends to convey in the mentioned question and answer, but also to explain the underlying hermeneutical thinking as well as to bring to the surface and explain alternative assumptions that ordinary church-going Christians experience as the unusual outcome of an unknown and different kind of approach. Different hermeneutical processes lead to different outcomes of understanding − sometimes worlds apart. Vanuit die sentrale punt van die opstanding van Jesus Christus in vraag en antwoord 45 van die Heidelbergse Kategismus, wil hierdie artikel in ’n hermeneutiese besinning oor die verskillende verbandhoudende historiese kontekste uitbrei. Die doel is nie slegs om die ware betekenis te vind van wat die Heidelbergse Kategismus in genoemde vraag en antwoord poog om weer te gee nie, maar ook om die onderliggende hermeneutiese denke te verduidelik en alternatiewe aannames, wat gewone Christen-kerkgangers as ’n vreemde en verskillende benaderings ervaar, na die oppervlakte te bring en te verduidelik. Verskillende hermeneutiese prosesse lei tot verskillende uitkomste van verstaan – soms wêrelde van mekaar verwyderd.

  1. The doctrine on God, as demonstrated and confessed in the Heidelberg Catechism

    Directory of Open Access Journals (Sweden)

    Carel F.C. Coetzee

    2013-06-01

    Full Text Available Although the Heidelberg Catechism (HC does not deal with a systematic doctrine on God and although there are not many sources available on the specific subject, it is a most important subject when dealing with the theology of the HC (W. van ’t Spijker. Due to the prescribed length of the article, it only focuses on two aspects of the doctrine on God, namely the Trinity and the relationship between God and the cosmos (reality. Futhermore, today there is an emphasis on a new concept of God, known as Panentheism. In this concept, God and his creation are identified with each other. In the South African context, the article deals very shortly with the viewpoints of Spangenberg, Van Aarde and Müller in this regard. The God confessed in the HC is the triune God: Father, Son and Holy Spirit. In the closest and most logical coherence with this, the HC confesses the deity of Christ and of the Holy Spirit. The HC also proceeds from the premise of the historical, bodily resurrection of Christ from the dead. As far as the relationship between God and creation is concerned, the HC, in agreement with the church of the first centuries, confesses and teaches a personal God, the Father of Jesus Christ, who for the sake of Christ is the Father of the elect. This God is the almighty creator of heaven and earth. He lives in a covenant relationship with his creation, which he sustains and governs at every moment. He is both transcendent and immanent.Alhoewel die Heidelbergse Kategismus (HK nie ’n sistematiese Godsleer bevat soos sommige van die ander belydenisskrifte nie en bronne oor die spesifieke onderwerp betreklik skaars is, is dit tog een van die belangrikste onderwerpe wanneer daar oor die teologie van die HK gehandel word (W. van ’t Spijker. Vanweë die voorgeskrewe lengte, word daar in hierdie artikel slegs op twee aspekte van die Godsleer gefokus, naamlik die Drie-eenheid en die verhouding van God tot die kosmos (werklikheid. Hierdie twee aspekte is

  2. Estrategias de barrido visual realizadas enla percepción de imágenes estáticas y su integración con la memoria visual de corto plazo

    Directory of Open Access Journals (Sweden)

    Yoiner CIFUENTES CORREA

    2012-04-01

    Full Text Available Los seres humanos están recibiendo permanentemente información a través de su sistema visual y el procesamiento de esta información visual le permitirá un mayor o menor grado de conocimiento y desempeño dentro del medio en que se mueve. La memoria en general y la memoria visual en particular es un proceso cognitivo básico que debe desarrollarse y está asociado con otras tareas cognitivas como la atención y procesos de comparación. En muchas actividades diarias es necesario hacer comparaciones futuras entre imágenes que ya fueron observadas, y en la medida en que el conocimiento espacial y el conocimiento de identidad de esas imágenes sea claro y preciso puede ser exitoso el proceso de comparación.La memoria visual de corto plazo (VSTM es una etapa intermedia en los procesos de memoria visual y resulta ser fundamental en la consolidación de la memoria visual de largo plazo (VLTM. Al observar una imagen estática o una escena del mundo real, los movimientos oculares realizan un barrido con el fin de capturar e integrar la mayor cantidad de información posible. Estos movimientos oculares, llamados movimientos sacádicos, pueden estar definidos por una estrategia de barrido visual particular, y el presente trabajo estudia esas estrategias para asociarlas con la VSTM.

  3. Retina projection using curved lens arrays

    Science.gov (United States)

    Yen, Hao-Ren; Su, Guo-Dung J.

    2016-09-01

    In this paper, we propose a multi-channel imaging system which combines the principles of an insect's compound eye and optical cluster eye. The system consists of two curved structure lens arrays with different pitches. Both of them have the same curvature and the radiuses of the lenses in the arrays are optimized to focus rays on the retina. The optical axes of different channels are tilted to each other in order to reduce the optical system volume and transmit a wide field of view. Each channel of an array of multiple optical system transfers only a part of the field of view. Each partial image passes through each channel and stitches together on the retina to reconstruct a complete image. In order to simulate the image stitching, we also build an eye model. The thickness from the panel to the last surface of lens group is less than 25mm. The panel size is designed to be 4 inch which is the scale of eyeglass. The system can provide a large field of view about 150 degrees which is much wider than the commercial products. By using the 3D printer, we can make a model of lens array to achieve our design.

  4. Ephaptic communication in the vertebrate retina

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    Rozan eVroman

    2013-09-01

    Full Text Available In the vertebrate retina, cones project to the horizontal cells (HCs and bipolar cells (BCs. The communication between cones and horizontal cells uses both chemical and ephaptic mechanisms. Photoreceptors release glutamate in a Ca2+-dependent manner, while HCs feed back to cones via an ephaptic mechanism. Hyperpolarization of HCs leads to an increased current through connexin hemichannels located on the tips of HC dendrites invaginating the cone synaptic terminals. This current makes the extracellular synaptic space slightly negative. The result is that the Ca2+-channels in the cone pre-synaptic membrane experience a slightly depolarized membrane potential and therefore more glutamate is released. This ephaptic mechanism forms a very fast and noise free negative feedback pathway. These characteristics are crucial, since the retina has to perform well in demanding conditions such as low light levels and detecting fast events. In this mini-review we will discuss the critical components of such an ephaptic mechanism. Furthermore, we will address the question whether such communication appears in other systems as well and indicate some fundamental features to look for when attempting to identify an ephaptic mechanism.

  5. The microglia in healthy and diseased retina.

    Science.gov (United States)

    Li, Lu; Eter, Nicole; Heiduschka, Peter

    2015-07-01

    The microglia are the immune cells of the central nervous system and, also the retina. They fulfil several tasks of surveillance in the healthy retina. In case of an injury or disease, microglia become activated and tries to repair the damage. However, in a lot of cases it does not work, and microglia deteriorate the situation by releasing toxic and pro-inflammatory compounds. Moreover, they further promote degenerative processes by attacking and phagocytosing damaged neurones and photoreceptors that otherwise would possibly have the chance to survive. Such deleterious action of the microglia has been observed in degeneration of retinal ganglion cells and photoreceptors, and it takes place in hereditary diseases, infections as well as in case of traumatic or light injuries. Therefore, a number of attempts has been undertaken so far to inhibit the microglia, with varying success. The task remains to study behaviour of the microglia and their interaction with other retinal cell populations in more detail with respect to released factors and expressed receptors including the time points of the corresponding events. The goal has to be to find a better balance between helpful and detrimental actions of the microglia.

  6. Association of tuberculosis with vasculitis retinae.

    Science.gov (United States)

    Habibullah, M; Uddin, M S; Islam, S

    2008-07-01

    Retinal vasculitis is one of the common causes of blindness among the young adult in this subcontinent. Causes of retinal vasculitis are variable and it is one of the common ocular manifestations of tuberculosis. This case control study was carried out on 45 patients with retinal vasculitis of different age groups. All the patients were purposively selected from the department of ophthalmology, Bangabandhu Sheikh Mujib Medical University and National Institute of Ophthalmology Dhaka. This study reveals that vasculitis retinae is a disease of younger age group (68.9%). Mean+/-SD age of cases were 31.84+/-10.82 years. It occurs more in male (75.6%) and male female ratio is 3.09:1, single or both eye may involve. Retinal vasculitis occurs more in middle socio-economic status persons (62.2%). It present with floaters (58.9%), hazy media (60%), vitreous haemorrhage (57.8%) and retinal haemorrhage (42.2%). All 45 subjects both cases and control groups were tested with Mantoux test. 18(40%) subjects of cases and 13(28.9%) subjects of control group were found positive Mantoux test. It was observed that the association of tuberculosis with vasculitis retinae is not statistically significant. As tuberculosis is common in this country, further specific and extensive study over a longer period of time is necessary for understanding the role of tuberculosis in retinal vasculitis patients.

  7. Designing and Implementation of Retina Image Drawing System and Automatic Report Generation from Retina Examinations

    Science.gov (United States)

    Safdari, Reza; Mokhtaran, Mehrshad; Tahmasebian, Shahram

    2016-01-01

    Introduction: Electronic medical records as one of major parts of electronic health records is an important application of Medical Informatics. EMR includes different types of data, Graphical items being one of these data types. To this end, a standard structure for storing and recovering and finally exchanging this data type is required. In order to standardize information items in this research, UMLS standard is used. In this research, graphical information from fondues designing in retina surgery forms is used for the task of implementation. Implementation: Three-layer software architecture is used for implementation of this system, which includes user interface, data base access and business logic. XML database is used for storing and exchanging of data. User interface is designed by the means of Adobe Flash. Also in the user interface for eye examinations, appropriate icons compatible with current pathologies in retina examinations are considered and UMLS codes are used for standardizations purposes. Results: As this project is independently implemented in Adobe Flash, it can be run in most of electronic patient records software. For evaluation purposes of this research, an EMR system for eye clinics is used. Tree structure is used for data entry and finally a text report based on the entered data will be generated. By storing graphical items in this software editing and searching in medical concepts and also comparing features will be available. Conclusion: One of the data items that we encounter in various medical records is graphical data. In order to cover the patient’s complete electronic medical records, the Electronic Implementation of this information is important. For this purpose, graphical items in retina surgery forms were used and finally a software application for drawing retina picture was developed. Also, XML files were used for the purpose of storing valuable medical data from the pictures, and also UMLS were applied for the standardization

  8. [Three-dimensional analysis of the foot following implantation of a HINTEGRA ankle prosthesis: evaluation with the Heidelberg foot model].

    Science.gov (United States)

    Müller, S; Wolf, S; Döderlein, L

    2006-05-01

    Detailed foot kinematics after total ankle replacement has not yet been investigated. In this study 11 patients with unilateral Hintegra ankle prosthesis were analysed with the Heidelberg Foot Model. This model measures the kinematics of the fore-, mid- and hindfoot in three clinical planes. Moreover, the kinetics of the hip, knee and ankle was captured. A diminished ROM was found in all foot segments investigated. The timing of the kinematics between sound and involved side appeared similar. A limitation in the hindfoot mobility, as experienced after ankle arthrodesis, was not observed. However, a careful hindfoot alignment is essential for optimal foot function, and previous malalignments should be corrected. Concerning the kinetics, the replaced ankle showed a decreased power generation compensated by an increase in power in the ipsilateral knee. For a more detailed evaluation, further studies are required which include pre- and postoperative data and also take into account different types of prostheses.

  9. Adaptive optics imaging of the retina.

    Science.gov (United States)

    Battu, Rajani; Dabir, Supriya; Khanna, Anjani; Kumar, Anupama Kiran; Roy, Abhijit Sinha

    2014-01-01

    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.

  10. 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.

  11. The Stuttgart-Heidelberg Model of Active Feedback Driven Quality Management: Means for the Optimization of Psychotherapy Provision

    Directory of Open Access Journals (Sweden)

    Hans Kordy

    2003-01-01

    Full Text Available La gestión de la calidad busca la evaluación del tratamiento psicoterapéutico. Un aspecto central se relaciona con el desarrollo de baterías de evaluación y criterios de evaluación adecuados. El modelo Stuttgart-Heidelberg (S-H representa un sistema que proporciona conceptos, instrumentos psicométricos y un programa informático desarrollado para la gestión de la calidad basada en el feedback activo. La información central del modelo Stuttgart-Heidelberg es el resultado individual del tratamiento. El planteamiento es que la psicoterapia puede mejorarse si proporcionamos información sobre los resultados terapéuticos (en especial los negativos, pues los procesos de solución de problemas se estimularán por el feedback recibido. El presente trabajo presenta un inventario de evaluación, la evaluación estandarizada de los resultados y las diversas herramientas de feedback del modelo SH. Un estudio sistemático incluyendo 1715 pacientes de un hospital especializado en trastornos psicosomáticos documenta la validez de este abordaje. Los resultados empíricos refuerzan una estrategia de transparencia acerca de lo que acontece en la práctica clínica – por ejemplo, acerca de los tratamientos administrados, sus resultados y costos. Implicaciones para la posterior optimización de los servicios de salud son discutidos.

  12. Colonization of internal organs by Salmonella serovars Heidelberg and Typhimurium in experimentally infected laying hens housed in enriched colony cages at different stocking densities

    Science.gov (United States)

    Contaminated eggs produced by infected commercial laying flocks are often implicated as sources of human infections with Salmonella Enteritidis, but Salmonella serovars Heidelberg and Typhimurium have also been associated with egg-transmitted illness. Contamination of the edible contents of eggs is ...

  13. Fluorescence spectroscopy of the retina from scrapie-infected mice.

    Science.gov (United States)

    Bose, Sayantan; Schönenbrücher, Holger; Richt, Jürgen A; Casey, Thomas A; Rasmussen, Mark A; Kehrli, Marcus E; Petrich, Jacob W

    2013-01-01

    Recently, we have proposed that the fluorescence spectra of sheep retina can be well correlated with the presence or absence of scrapie. Scrapie is the most widespread TSE (transmissible spongiform encephalopathy) affecting sheep and goats worldwide. Mice eyes have been previously reported as a model system to study age-related accumulation of lipofuscin, which has been investigated by monitoring the increasing fluorescence with age covering its entire life span. The current work aims at developing mice retina as a convenient model system to diagnose scrapie and other fatal TSE diseases in animals such as sheep and cows. The objective of the research reported here was to determine whether the spectral features are conserved between two different species namely mice and sheep, and whether an appropriate small animal model system could be identified for diagnosis of scrapie based on the fluorescence intensity in retina. The results were consistent with the previous reports on fluorescence studies of healthy and scrapie-infected retina of sheep. The fluorescence from the retinas of scrapie-infected sheep was significantly more intense and showed more heterogeneity than that from the retinas of uninfected mice. Although the structural characteristics of fluorescence spectra of scrapie-infected sheep and mice eyes are slightly different, more importantly, murine retinas reflect the enhancement of fluorescence intensity upon infecting the mice with scrapie, which is consistent with the observations in sheep eyes.

  14. Adaptive optics optical coherence tomography for retina imaging

    Institute of Scientific and Technical Information of China (English)

    Guohua Shi; Yun Dai; Ling Wang; Zhihua Ding; Xuejun Rao; Yudong Zhang

    2008-01-01

    When optical coherence tomography (OCT) is used for human retina imaging, its transverse resolution is limited by the aberrations of human eyes. To overcome this disadvantage, a high resolution imaging system for living human retina, which consists of a time domain OCT system and a 37-elements adaptive optics (AO) system, has been developed. The AO closed loop rate is 20 frames per second, and the OCT has a 6.7-μm axial resolution. In this paper, this system is introduced and the high resolution imaging results for retina are presented.

  15. Cementos Belíticos: caracterización de los productos de hidratación por microscopía electronica de barrido y microanálisis de rayos x

    OpenAIRE

    Goñi Elizalde, Sara; Guerrero Bustos, Ana; Lorenzo García, Mª Paz

    2008-01-01

    En este trabajo se presenta la caracterización microscópica de dos tipos de cementos belíticos de cenizas volantes (CBCV) y sus productos de hidratación, por medio de microscopía electrónica de barrido, microanálisis cuantitativo por energía dispersa de rayos X y difracción de rayos X. Los cementos se sintetizaron a partir de cenizas volantes de la combustión de carbón, de alto contenido en cal, empleando una ruta de síntesis de baja energía basada en la obtención de fases precursoras del cem...

  16. Aplicación del análisis por calorimetría diferencial de barrido (DSC para la caracterización de las modificaciones del almidón

    Directory of Open Access Journals (Sweden)

    ANGELICA SANDOVAL ALDANA

    2005-01-01

    Full Text Available La calorimetría diferencial de barrido (DSC, por sus siglas en ingles es un análisis térmico que ha permitido identificar en un sistema compuesto de almidón y agua las transiciones y modificaciones de la estructura del gránulo de almidón, verificar la asociación de fragmentos de amilosa y amilopectina (retrogradación e identificar los cambios en sus características térmicas como consecuencia de tratamientos combinados de calor y humedad. Esta revisión presenta conceptos sobre el DSC, la estructura y las transiciones de fase del gránulo de almidón. Adicionalmente, se recopilan investigaciones donde se utilizó esta técnica para la caracterización de distintos almidones.

  17. Pharmacology of the GABAB receptor in amphibian retina.

    Science.gov (United States)

    Tian, N; Slaughter, M M

    1994-10-17

    Amacrine and ganglion cells in the amphibian retina contain GABAB, as well as GABAA, receptors. Baclofen, a GABAB agonist, hyperpolarizes the dark membrane potential of these third order neurons and makes their light responses more transient. GABAB receptors in the retina have a similar agonist profile to GABAB receptors described at other sites in the brain. Namely, preferential activation by the R-enantiomer of baclofen, and agonist sensitivity in the order 3-aminopropylphosphinic acid > baclofen > 3-aminopropylphosphonic acid. The GABAB receptor was not activated by 4-aminobutylphosphonic acid. Several antagonists, such as phaclofen, saclofen, and 2-hydroxysaclofen, were ineffective in the amphibian retina. However, CGP35348 blocked the action of applied baclofen and produced effects on the light response that were opposite to those of baclofen. Applied agonists and antagonists support the hypothesis that GABAB receptors serve to regulate the balance of sustained and transient signals to the inner retina.

  18. The risk of retina damage from high intensity light sources.

    Science.gov (United States)

    Pollak, V A; Romanchuk, K G

    1980-05-01

    The risk of thermal damage to the retina of the eye by exposure to excessive light intensities from continuous and pulsed man-made sources is discussed. The probability of injury increases, the larger the radiant power absorbed by the retina and the smaller the size of the retinal image of the source. A mehtod of estimating the temperature increase of the immediately affected area of the retina is presented. The time constants involved are also briefly considered. Using numerical values from literature for the relevant parameters of the eye, threshold values for a variety of conditions can be established. Below these values little risk of retina damage should exist. The degree of hazard when these values are exceeded depends upon the circumstances. A case study of a welding accident showed good agreement between the conclusions of the theoretical analysis and clinical findings.

  19. 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.

  20. Genetics Home Reference: gyrate atrophy of the choroid and retina

    Science.gov (United States)

    ... newborn period. Gyrate atrophy usually does not affect intelligence; however, abnormalities may be observed in brain imaging ... the choroid and retina in a child with myopia. Indian Pediatr. 2001 Aug;38(8):914-8. ...

  1. Glutamine synthetase localization in cortisol-induced chick embryo retinas

    OpenAIRE

    1980-01-01

    We report here for the first time, in chick retina, Muller cell localization of glutamine synthetase (GS) activity by an immunohistochemical technique, in agreement with previous reports of glial localization of this enzyme in rat brain and retina. Age- dependent changes in the endogenous enzyme activity as well as cortisol- induced changes in GS activity, both in ovo and in vitro, measured biochemically, reflect the changes observed by staining.

  2. Light-evoked S-nitrosylation in the retina.

    Science.gov (United States)

    Tooker, Ryan E; Vigh, Jozsef

    2015-10-01

    Nitric oxide (NO) synthesis in the retina is triggered by light stimulation. NO has been shown to modulate visual signal processing at multiple sites in the vertebrate retina, via activation of the most sensitive target of NO signaling, soluble guanylate cyclase. NO can also alter protein structure and function and exert biological effects directly by binding to free thiol groups of cysteine residues in a chemical reaction called S-nitrosylation. However, in the central nervous system, including the retina, this reaction has not been considered to be significant under physiological conditions. Here we provide immunohistochemical evidence for extensive S-nitrosylation that takes place in the goldfish and mouse retinas under physiologically relevant light intensities, in an intensity-dependent manner, with a strikingly similar pattern in both species. Pretreatment with N-ethylmaleimide (NEM), which occludes S-nitrosylation, or with 1-(2-trifluromethylphenyl)imidazole (TRIM), an inhibitor of neuronal NO synthase, eliminated the light-evoked increase in S-nitrosylated protein immunofluorescence (SNI) in the retinas of both species. Similarly, light did not increase SNI, above basal levels, in retinas of transgenic mice lacking neuronal NO synthase. Qualitative analysis of the light-adapted mouse retina with mass spectrometry revealed more than 300 proteins that were S-nitrosylated upon illumination, many of which are known to participate directly in retinal signal processing. Our data strongly suggest that in the retina light-evoked NO production leads to extensive S-nitrosylation and that this process is a significant posttranslational modification affecting a wide range of proteins under physiological conditions.

  3. 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.

  4. Transformation of stimulus correlations by the retina.

    Directory of Open Access Journals (Sweden)

    Kristina D Simmons

    Full Text Available Redundancies and correlations in the responses of sensory neurons may seem to waste neural resources, but they can also carry cues about structured stimuli and may help the brain to correct for response errors. To investigate the effect of stimulus structure on redundancy in retina, we measured simultaneous responses from populations of retinal ganglion cells presented with natural and artificial stimuli that varied greatly in correlation structure; these stimuli and recordings are publicly available online. Responding to spatio-temporally structured stimuli such as natural movies, pairs of ganglion cells were modestly more correlated than in response to white noise checkerboards, but they were much less correlated than predicted by a non-adapting functional model of retinal response. Meanwhile, responding to stimuli with purely spatial correlations, pairs of ganglion cells showed increased correlations consistent with a static, non-adapting receptive field and nonlinearity. We found that in response to spatio-temporally correlated stimuli, ganglion cells had faster temporal kernels and tended to have stronger surrounds. These properties of individual cells, along with gain changes that opposed changes in effective contrast at the ganglion cell input, largely explained the pattern of pairwise correlations across stimuli where receptive field measurements were possible.

  5. Efficient control structures for digital programmable retinas

    Science.gov (United States)

    Bernard, Thierry M.

    2001-05-01

    A digital programmable artificial retina (PAR) is a functional extension of a CMOS imager, in which every pixel is fitted with a local ADC and a tiny digital programmable processor. From an architectural viewpoint, a PAR is an SIMD array processor with local optical input. A PAR is aimed at processing images on-site until they can be output from the array under concentrated form. The overall goal is to get compact, fast and inexpensive vision systems, in particular for robotics applications. A 256 by 256 PAR with up to a few tens bits of local memory per pixel is now within reach at reasonable cost. However, whereas the local memory size benefits quadratically from the feature size decrease, wiring density improvement can only be linear, at best. So control should become more complex with the danger of a growing proportion of the digital pixel area being devoted to instruction or address decoding. We propose efficient scalable solutions to this problem at the architectural, circuit and topological levels, which attempt to minimize both silicon area and power consumption.

  6. Transformation of stimulus correlations by the retina.

    Science.gov (United States)

    Simmons, Kristina D; Prentice, Jason S; Tkačik, Gašper; Homann, Jan; Yee, Heather K; Palmer, Stephanie E; Nelson, Philip C; Balasubramanian, Vijay

    2013-01-01

    Redundancies and correlations in the responses of sensory neurons may seem to waste neural resources, but they can also carry cues about structured stimuli and may help the brain to correct for response errors. To investigate the effect of stimulus structure on redundancy in retina, we measured simultaneous responses from populations of retinal ganglion cells presented with natural and artificial stimuli that varied greatly in correlation structure; these stimuli and recordings are publicly available online. Responding to spatio-temporally structured stimuli such as natural movies, pairs of ganglion cells were modestly more correlated than in response to white noise checkerboards, but they were much less correlated than predicted by a non-adapting functional model of retinal response. Meanwhile, responding to stimuli with purely spatial correlations, pairs of ganglion cells showed increased correlations consistent with a static, non-adapting receptive field and nonlinearity. We found that in response to spatio-temporally correlated stimuli, ganglion cells had faster temporal kernels and tended to have stronger surrounds. These properties of individual cells, along with gain changes that opposed changes in effective contrast at the ganglion cell input, largely explained the pattern of pairwise correlations across stimuli where receptive field measurements were possible.

  7. Remediation measures at the former hazardous waste dump at Malsch near Heidelberg; Sanierung der ehemaligen Sonderabfalldeponie Malsch. Hydrogeologische Bewertung

    Energy Technology Data Exchange (ETDEWEB)

    Hanstein, P.; Hoetzl, H. [Karlsruhe Univ. (T.H.) (Germany). Lehrstuhl fuer Angewandte Geologie

    1998-12-31

    The former hazardous waste deposit of Malsch is located south of Heidelberg at the eastern margin of the Upper Rhine Graben. Using a former clay pit about 700.000 m{sup 3} of partly high toxic organic and inorganic wastes were deposited from 1971 to 1984. A leakage from the deposit was first recognised in 1984. Detailed investigation showed that thin channel-like conglomerate layers intercalated in the clays and marls as well as faults are cropping out into the base of the deposit and cause a direct seepage of leachate. Contaminants pollute the downstream area over a distance of 500 m. Remediation measures adding up to 100 Mio. DM were carried out including the construction of a slurry wall encircling laterally the whole site, a surface cover with a multi-liner system as well as a pump and treat system for the leachate was installed and are now in operation. Model studies of the ground water flow including a 3-dimensional site model and a 2-dimensional regional model started during the remediation work. According to the complex geological situation specific procedures was applied to transform the heterogeneous tectonical structure into the numerical models. The balance of water flowing through the deposit was calculated by the piezometric heads to assess different remediation stages. In spite of the missing impervious base the calculation could prove that in connection of a certain pumping rate of the leachate the environment and especially the groundwater can be protected from further leakage. (orig.) [Deutsch] Die fruehere Sonderabfalldeponie Malsch wurde 1971 in einer stillgelegten Tongrube suedlich von Heidelberg am oestlichen Rand des Oberrheingrabens angelegt und bis 1984 betrieben. Insgesamt wurden ueber 700.000 m{sup 3} zum Teil hochtoxische organische und anorganische Sonderabfaelle abgelagert. Mit Abschluss der Deponierungsphase wurden Sickerwasseraustritte im westlichen Deponievorfeld festgelstellt. Ursache fuer die Undichtigkeiten waren geringmaechtige

  8. Gene Transcription Profile of the Detached Retina (An AOS Thesis)

    Science.gov (United States)

    Zacks, David N.

    2009-01-01

    Purpose: Separation of the neurosensory retina from the retinal pigment epithelium (RPE) yields many morphologic and functional consequences, including death of the photoreceptor cells, Müller cell hypertrophy, and inner retinal rewiring. Many of these changes are due to the separation-induced activation of specific genes. In this work, we define the gene transcription profile within the retina as a function of time after detachment. We also define the early activation of kinases that might be responsible for the detachment-induced changes in gene transcription. Methods: Separation of the retina from the RPE was induced in Brown-Norway rats by the injection of 1% hyaluronic acid into the subretinal space. Retinas were harvested at 1, 7, and 28 days after separation. Gene transcription profiles for each time point were determined using the Affymetrix Rat 230A gene microarray chip. Transcription levels in detached retinas were compared to those of nondetached retinas with the BRB-ArrayTools Version 3.6.0 using a random variance analysis of variance (ANOVA) model. Confirmation of the significant transcriptional changes for a subset of the genes was performed using microfluidic quantitative real-time polymerase chain reaction (qRT-PCR) assays. Kinase activation was explored using Western blot analysis to look for early phosphorylation of any of the 3 main families of mitogen-activated protein kinases (MAPK): the p38 family, the Janus kinase family, and the p42/p44 family. Results: Retinas separated from the RPE showed extensive alterations in their gene transcription profile. Many of these changes were initiated as early as 1 day after separation, with significant increases by 7 days. ANOVA analysis defined 144 genes that had significantly altered transcription levels as a function of time after separation when setting a false discovery rate at ≤0.1. Confirmatory RT-PCR was performed on 51 of these 144 genes. Differential transcription detected on the microarray

  9. Tomographic LP-DOAS measurements of 2D trace gas distributions above the city of Heidelberg, Germany

    Energy Technology Data Exchange (ETDEWEB)

    Poehler, Denis; Hartl, Andreas; Platt, Ulrich [Institute of Environmental Physics, University of Heidelberg (Germany)

    2007-07-01

    LP-DOAS (Long Path-Differential Optical Absorption Spectroscopy) is a well known remote sensing technique for measuring the average concentration of tropospheric trace gases along extended light paths in the open atmosphere. In order to retrieve information of the spatial trace gas distribution tomographic LP-DOAS measurements are useful. They combine the measurement along several intersecting light paths with tomographic inversion techniques and allow 2 and 3 dimensional retrieval of trace gas distributions. In a campaign in Heidelberg, Germany, a measurement set-up encompassing a total of 18 horizontal light paths by using three, Multibeam, LP-DOAS instruments is being tested. In the wavelength range from 285 nm to 365 nm the average concentrations of the trace gases NO{sub 2}, SO{sub 2}, O{sub 3}, HCHO and HONO along each light path could be retrieved with a temporal resolution below 15 minutes. The first evaluated data from winter 2005/06 show high accuracy for NO{sub 2} and SO{sub 2} mean concentrations. They allow deriving for these trace gases twodimensional distributions above the city. Different emission sources varying strongly in space and time can be identified. The results demonstrate that tomographic DOAS measurements can be used to study emissions and transport of trace gases and can be used to evaluate models predicting the air quality.

  10. Status of the 7 MeV/u, 217 MHz Injector Linac for the Heidelberg Cancer Therapy Facility

    CERN Document Server

    Schlitt, B; Hutter, G; Klos, F; Lu, Y; Minaev, S A; Mühle, C; Ratzinger, U; Schlitt, B; Tiede, R; Vinzenz, W; Will, C; Zurkan, O

    2004-01-01

    A clinical synchrotron facility for cancer therapy using energetic proton and ion beams (C, He and O) is under construction and will be installed at the Radiologische Universitätsklinik in Heidelberg, Germany, starting in 2005. The status of the ECR ion source systems, the beam line components of the low energy beam transport lines, the 400 keV/u RFQ and the 20 MV IH-cavity as well as the linac rf system will be reported. Two prototype magnets of the linac quadrupole magnets have been built at GSI and have been tested successfully. A test bench for the 1.4 MW, 217 MHz cavity amplifier built by industry has been installed at GSI including a 120 kW driver amplifier which will be used also for high power tests of the RFQ. A test bench for the RFQ using proton beams is presently being set up at the IAP. RF tuning of the 1:2 scaled IH-DTL model as well as Microwave Studio simulations of the model and the power cavity have been also performed at the IAP [1].

  11. Fünf Jahre Erfahrung mit dem curricularen Einsatz des fall- und webbasierten Lernsystems "CAMPUS-Pädiatrie" an der Medizinischen Fakultät Heidelberg [

    Directory of Open Access Journals (Sweden)

    Huwendiek, Sören

    2006-02-01

    Full Text Available [english] "CAMPUS-Paediatrics" is an application of the computer-based learning system "CAMPUS" (http://www.medicase.de, with which authentic cases from the department of paediatric and juvenile medicine are presented in a realistic, interactive and multimedial way in order to test and improve the medical problem-solving competence of students. At the university clinic for paediatric and juvenile medicine in Heidelberg, this programme has been in use for five years within the context of tutorials and compulsory classes in small groups; the contents produced are relevant to examinations. The independent examination of the case on the computer in combination with dialogue and exchange of experiences with other students and the tutor in the sense of "blended learning" was judged in a number of evaluations by the students to be extremely effective. The project was/will be funded by the Ministry for Science and Art, Baden-Württemberg, the Federal Ministry for Education and Research and the Medical Faculty in Heidelberg. [german] "CAMPUS-Pädiatrie" ist eine Anwendung des computerbasierten Lernsystems "CAMPUS" (, mit dem authentische Fälle aus dem Fachbereich Kinder- und Jugendmedizin in einer realitätsnahen, interaktiven und multimedialen Weise bereitgestellt werden, um die medizinische Problemlösekompetenz von Studierenden zu testen und zu verbessern. An der Universitätsklinik für Kinder- und Jugendmedizin Heidelberg wird dieses Programm seit fünf Jahren im Rahmen des tutoriell betreuten und anwesenheitspflichtigen Kleingruppenunterrichts eingesetzt; die erarbeiteten Inhalte sind prüfungsrelevant. Die selbstständige Auseinandersetzung mit dem Lernfall am Computer in Kombination mit dem Gespräch und Erfahrungsaustausch mit anderen Studenten und dem Tutor im Sinne von "Blended Learning" wurde von den Studierenden in mehreren Evaluationen als sehr effektiv beurteilt. Das Projekt wurde bzw. wird vom MWK Baden-Württemberg, dem BMBF und der

  12. Creating student sleuths: how a team of graduate students helped solve an outbreak of Salmonella Heidelberg infections associated with kosher broiled chicken livers.

    Science.gov (United States)

    Hanson, Heather; Hancock, W Thane; Harrison, Cassandra; Kornstein, Laura; Waechter, HaeNa; Reddy, Vasudha; Luker, John; Malavet, Michelle; Huth, Paula; Gieraltowski, Laura; Balter, Sharon

    2014-08-01

    Since 2009, the New York City Department of Health and Mental Hygiene (DOHMH) has received FoodCORE funding to hire graduate students to conduct in-depth food exposure interviews of salmonellosis case patients. In 2011, an increase in the number of Salmonella Heidelberg infections with pulsed-field gel electrophoresis Xba I pattern JF6X01.0022 among observant Jewish communities in New York and New Jersey was investigated. As this pattern is common nationwide, some cases identified were not associated with the outbreak. To reduce the number of background cases, DOHMH focused on the community initially identified in the outbreak and defined a case as a person infected with the outbreak strain of Salmonella Heidelberg with illness onset from 1 April to 17 November 2011 and who consumed a kosher diet, spoke Yiddish, or self-identified as Jewish. Nationally, 190 individuals were infected with the outbreak strain of Salmonella Heidelberg; 63 New York City residents met the DOHMH case definition. In October 2011, the graduate students (Team Salmonella) interviewed three case patients who reported eating broiled chicken livers. Laboratory testing of chicken liver samples revealed the outbreak strain of Salmonella Heidelberg. Although they were only partially cooked, the livers appeared fully cooked, and consumers and retail establishment food handlers did not cook them thoroughly before eating or using them in a ready-to-eat spread. This investigation highlighted the need to prevent further illnesses from partially cooked chicken products. Removing background cases helped to focus the investigation. Training graduate students to collect exposure information can be a highly effective model for conducting foodborne disease surveillance and outbreak investigations for local and state departments of public health.

  13. Behavior of Salmonella heidelberg and Salmonella enteritidis strains following broiler chick inoculation: evaluation of cecal morphometry, liver and cecum bacterial counts and fecal excretion patterns

    Directory of Open Access Journals (Sweden)

    Anderlise Borsoi

    2011-03-01

    Full Text Available Over the years, Salmonella Heidelberg (SH has gained prominence in North America poultry production and in the poultry production of other countries. Salmonella Heidelberg has been isolated and reported from poultry and poultry products in Brazil since 1962, whereas Salmonella Enteritidis (SE has only emerged as a serious problem in poultry and public health since 1993. These strains of Salmonella can cause intestinal problems in newly hatched chicks, and infection may persist until adulthood. Upon slaughter of chickens, Salmonella can contaminate carcasses, a condition that poses a threat to human health. The aim of this study was to compare the fecal excretion of Salmonella Enteritidis and Salmonella Heidelberg in newly hatched chicks (orally inoculated with 10(5ufc/mL each until 20 days of age. In addition, the ratio of cecal villus height:crypt depth (morphometry and liver and cecum cell counts was analyzed in chicks ranging from 0 to 3 days of age and infected with these two Salmonella strains. One hundred seventeen chicks were separated into one of three experimental groups: a control group, an SE-infected group and an SH-infected group. Eight chicks per group were euthanized at 6, 12 and 72 hours post-inoculation (pi to allow for Salmonella isolation from the liver and cecum and for the collection of the cecum for villi and crypt analysis. Other birds were allowed to mature to 20 days of age and cloacal swabs were taken at 2, 6, 13 and 20 days pi to compare the fecal excretion of inoculated strains. The Salmonella Enteritidis group had a higher number of cells excreted during the trial. Both strains were isolated from the liver and cecum by 6h pi. At 12h pi the Salmonella Heidelberg group had high cell counts in the cecum. No difference was found in liver cell counts. Both strains showed lower villus height:crypt depth ratio than the control group post-infection.

  14. Behavior of salmonella heidelberg and salmonella enteritidis strains following broiler chick inoculation: evaluation of cecal morphometry, liver and cecum bacterial counts and fecal excretion patterns.

    Science.gov (United States)

    Borsoi, Anderlise; Ruschel do Santos, Luciana; Beatriz Rodrigues, Laura; Luiz de Souza Moraes, Hamilton; Tadeu Pippi Salle, Carlos; Pinheiro do Nascimento, Vladimir

    2011-01-01

    Over the years, Salmonella Heidelberg (SH) has gained prominence in North America poultry production and in the poultry production of other countries. Salmonella Heidelberg has been isolated and reported from poultry and poultry products in Brazil since 1962, whereas Salmonella Enteritidis (SE) has only emerged as a serious problem in poultry and public health since 1993. These strains of Salmonella can cause intestinal problems in newly hatched chicks, and infection may persist until adulthood. Upon slaughter of chickens, Salmonella can contaminate carcasses, a condition that poses a threat to human health. The aim of this study was to compare the fecal excretion of Salmonella Enteritidis and Salmonella Heidelberg in newly hatched chicks (orally inoculated with 10(5)ufc/mL each) until 20 days of age. In addition, the ratio of cecal villus height:crypt depth (morphometry) and liver and cecum cell counts was analyzed in chicks ranging from 0 to 3 days of age and infected with these two Salmonella strains. One hundred seventeen chicks were separated into one of three experimental groups: a control group, an SE-infected group and an SH-infected group. Eight chicks per group were euthanized at 6, 12 and 72 hours post-inoculation (pi) to allow for Salmonella isolation from the liver and cecum and for the collection of the cecum for villi and crypt analysis. Other birds were allowed to mature to 20 days of age and cloacal swabs were taken at 2, 6, 13 and 20 days pi to compare the fecal excretion of inoculated strains. The Salmonella Enteritidis group had a higher number of cells excreted during the trial. Both strains were isolated from the liver and cecum by 6h pi. At 12h pi the Salmonella Heidelberg group had high cell counts in the cecum. No difference was found in liver cell counts. Both strains showed lower villus height:crypt depth ratio than the control group post-infection.

  15. Impact of plasmids, including those encodingVirB4/D4 type IV secretion systems, on Salmonella enterica serovar Heidelberg virulence in macrophages and epithelial cells.

    Directory of Open Access Journals (Sweden)

    Kuppan Gokulan

    Full Text Available Salmonella enterica serovar Heidelberg (S. Heidelberg can cause foodborne illness in humans following the consumption of contaminated meat and poultry products. Recent studies from our laboratory have demonstrated that certain S. Heidelberg isolated from food-animal sources harbor multiple transmissible plasmids with genes that encode antimicrobial resistance, virulence and a VirB4/D4 type-IV secretion system. This study examines the potential role of these transmissible plasmids in bacterial uptake and survival in intestinal epithelial cells and macrophages, and the molecular basis of host immune system modulation that may be associated with disease progression. A series of transconjugant and transformant strains were developed with different combinations of the plasmids to determine the roles of the individual and combinations of plasmids on virulence. Overall the Salmonella strains containing the VirB/D4 T4SS plasmids entered and survived in epithelial cells and macrophages to a greater degree than those without the plasmid, even though they carried other plasmid types. During entry in macrophages, the VirB/D4 T4SS encoding genes are up-regulated in a time-dependent fashion. When the potential mechanisms for increased virulence were examined using an antibacterial Response PCR Array, the strain containing the T4SS down regulated several host innate immune response genes which likely contributed to the increased uptake and survival within macrophages and epithelial cells.

  16. Impact of plasmids, including those encodingVirB4/D4 type IV secretion systems, on Salmonella enterica serovar Heidelberg virulence in macrophages and epithelial cells.

    Science.gov (United States)

    Gokulan, Kuppan; Khare, Sangeeta; Rooney, Anthony W; Han, Jing; Lynne, Aaron M; Foley, Steven L

    2013-01-01

    Salmonella enterica serovar Heidelberg (S. Heidelberg) can cause foodborne illness in humans following the consumption of contaminated meat and poultry products. Recent studies from our laboratory have demonstrated that certain S. Heidelberg isolated from food-animal sources harbor multiple transmissible plasmids with genes that encode antimicrobial resistance, virulence and a VirB4/D4 type-IV secretion system. This study examines the potential role of these transmissible plasmids in bacterial uptake and survival in intestinal epithelial cells and macrophages, and the molecular basis of host immune system modulation that may be associated with disease progression. A series of transconjugant and transformant strains were developed with different combinations of the plasmids to determine the roles of the individual and combinations of plasmids on virulence. Overall the Salmonella strains containing the VirB/D4 T4SS plasmids entered and survived in epithelial cells and macrophages to a greater degree than those without the plasmid, even though they carried other plasmid types. During entry in macrophages, the VirB/D4 T4SS encoding genes are up-regulated in a time-dependent fashion. When the potential mechanisms for increased virulence were examined using an antibacterial Response PCR Array, the strain containing the T4SS down regulated several host innate immune response genes which likely contributed to the increased uptake and survival within macrophages and epithelial cells.

  17. Estimating the number of human cases of ceftiofur-resistant Salmonella enterica serovar Heidelberg in Québec and Ontario, Canada.

    Science.gov (United States)

    Otto, Simon J G; Carson, Carolee A; Finley, Rita L; Thomas, M Kate; Reid-Smith, Richard J; McEwen, Scott A

    2014-11-01

    A stochastic model was used to estimate the number of human cases of ceftiofur-resistant Salmonella enterica serovar Heidelberg in Québec and Ontario attributable to chicken consumption and excess cases attributable to human prior antimicrobial consumption. The annual mean incidence of S. Heidelberg (Québec/Ontario) decreased from 70/62 cases per 100 000 in 2004 to 29/30 cases per 100 000 in 2007 (Québec)/2008 (Ontario), increasing to 59/45 cases per 100 000 in 2011. The annual mean incidence of ceftiofur-resistant cases from chicken decreased from 8/7 cases per 100 000 in 2004 to 1/1 cases per 100 000 in 2007 (Québec)/2008 (Ontario), increasing to 7/5 cases per 100 000 in 2011. The annual mean total number of excess ceftiofur-resistant cases from chicken attributable to human prior antimicrobial consumption (Québec/Ontario) decreased from 71/123 in 2004 to 6/24 in 2007 (Québec)/2008 (Ontario), but increased to 62/91 in 2011. This model will support future work to determine the increased severity, mortality and healthcare costs for ceftiofur-resistant Salmonella Heidelberg infections. These results provide a basis for the evaluation of future public health interventions to address antimicrobial resistance.

  18. Retina neural circuitry seen with particle detector technology

    CERN Document Server

    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...

  19. Neuropeptide Y system in the retina: From localization to function.

    Science.gov (United States)

    Santos-Carvalho, Ana; Ambrósio, António Francisco; Cavadas, Cláudia

    2015-07-01

    The retina is a highly complex structure where several types of cells communicate through countless different molecules to codify visual information. Each type of cells plays unique roles in the retina, presenting a singular expression of neurotransmitters. Some neurotransmitter systems in the retina are well understood, while others need to be better explored to unravel the intricate signaling system involved. Neuropeptide Y (NPY), a 36 amino acid peptide, is one of the most common peptide neurotransmitter in the CNS and a highly conserved peptide among species. We review the localization of NPY and NPY receptors (mainly NPY Y1, Y2, Y4 and Y5) in retinal cells. Common features of the expression of NPY and NPY receptors in mammalian and non-mammalian species indicate universal roles of this system in the retina. In the present review, we highlight the putative roles of NPY receptor activation in the retina, discussing, in particular, their involvement in retinal development, neurotransmitter release modulation, neuroprotection, microglia and Muller cells function, retinal pigmented epithelium changes, retinal endothelial physiology and proliferation of retinal progenitor cells. Further studies are needed to confirm that targeting the NPY system might be a potential therapeutic strategy for retinal degenerative diseases.

  20. Bmp4 from the optic vesicle specifies murine retina formation.

    Science.gov (United States)

    Huang, Jie; Liu, Ying; Oltean, Alina; Beebe, David C

    2015-06-01

    Previous studies of mouse embryos concluded that after the optic vesicle evaginates from the ventral forebrain and contacts the surface ectoderm, signals from the ectoderm specify the distal region of the optic vesicle to become retina and signals from the optic vesicle induce the lens. Germline deletion of Bmp4 resulted in failure of lens formation. We performed conditional deletion of Bmp4 from the optic vesicle to test the function of Bmp4 in murine eye development. The optic vesicle evaginated normally and contacted the surface ectoderm. Lens induction did not occur. The optic cup failed to form and the expression of retina-specific genes decreased markedly in the distal optic vesicle. Instead, cells in the prospective retina expressed genes characteristic of the retinal pigmented epithelium. We conclude that Bmp4 is required for retina specification in mice. In the absence of Bmp4, formation of the retinal pigmented epithelium is the default differentiation pathway of the optic vesicle. Differences in the signaling pathways required for specification of the retina and retinal pigmented epithelium in chicken and mouse embryos suggest major changes in signaling during the evolution of the vertebrate eye.

  1. Selective Gene Transfer to the Retina Using Intravitreal Ultrasound Irradiation

    Directory of Open Access Journals (Sweden)

    Shozo Sonoda

    2012-01-01

    Full Text Available This paper aims to evaluate the efficacy of intravitreal ultrasound (US irradiation for green fluorescent protein (GFP plasmid transfer into the rabbit retina using a miniature US transducer. Intravitreal US irradiation was performed by a slight modification of the transconjunctival sutureless vitrectomy system utilizing a small probe. After vitrectomy, the US probe was inserted through a scleral incision. A mixture of GFP plasmid (50 μL and bubble liposomes (BLs; 50 μL was injected into the vitreous cavity, and US was generated to the retina using a SonoPore 4000. The control group was not exposed to US. After 72 h, the gene-transfer efficiency was quantified by counting the number of GFP-positive cells. The retinas that received plasmid, BL, and US showed a significant increase in the number (average ± SEM of GFP-positive cells (32±4.9; n=7; P<0.01 . No GFP-positive cells were observed in the control eyes (n=7. Intravitreal retinal US irradiation can transfer the GFP plasmid into the retina without causing any apparent damage. This procedure could be used to transfer genes and drugs directly to the retina and therefore has potential therapeutic value.

  2. THE DIAGNOSTIC VALUE OF MEASUREMENT OF POSTERIOR POLE RETINAL THICKNESS WITH HEIDELBERG OCT IN GLAUCOMA%海德堡OCT测量后极部视网膜厚度对青光眼诊断价值

    Institute of Scientific and Technical Information of China (English)

    邢业娇; 王大博; 纪珍; 刘鹏辉

    2013-01-01

    Objective To observe the posterior pole retinal thickness of normal and glaucoma measured by optical coherence tomognaphy (OCT), and evaluate its value in the diagnosis of glaucoma. Methods The thickness of posterior pole retina of 40 normal cases (40 eyes) and 41 glaucoma (64 eyes, including 53 POAG and 11 PACG) were respectively measured by Heidelberg Spectralis OCT. The image features of posterior pole retinal mapping in normal individuals and patients with glaucoma were observed and compared, the correlation between MD and retinal thickness was calculated as well. Results The posterior pole retinal mapping in normal persons appeared as U-shaped, and that shape was not typical or disappeared in glaucoma. There was no statistical difference among the thickness of posterior pole retinal in average, superior and inferior in health adult group (F = 0. 800,P>0. 05) , in patients with glaucoma, the thickness of posterior pole retinal was thinner than that in normal group (F = 59. 569 — 72. 364,P<0. 01) ; the same finding was also appeared in early glaucoma (t = 2. 828,P<0. 01). The posterior pole retinal thickness in glaucoma was negatively correlated with MD (r= —0. 619,P<0. 01). Conclusion In glaucoma, the changes of thickness of posterior pole retina have a close correlation with changes of function of visual field, and appear earlier than defect of visual field, which is likely to be a marker to replace detection of retinal ganglion cell loss.%目的 利用光学相干断层扫描技术(OCT)观察正常眼和青光眼后极部视网膜厚度,评价其对青光眼的诊断价值.方法 采用海德堡Spectralis OCT对40例(40眼)正常人和41例(64眼)青光眼(包括53眼POAG和11眼PACG)病人后极部视网膜厚度进行测量,观察正常人和青光眼病人后极部视网膜厚度地形图的图像特征并进行比较;并分析其与视野平均缺损值(MD)的相关性.结果 正常人后极部视网膜厚度地形图呈“马蹄形”,青光眼

  3. The mechanism of pattern formation in the developing drosophila retina

    Institute of Scientific and Technical Information of China (English)

    SUN QiCheng

    2007-01-01

    The biological patterning of the drosophila retina in vivo has striking resemblance to liquid bubbles, in which the surface mechanics due to N-cadherin within a sub-group of retina cells can be mimicked by surface tension. In this work, the aggregating patterns were reasonably simplified into 2D clusters consisting of 2-6 identical bubbles confined within a shrinking boundary. By using a hybrid fluid dynamics model proposed for liquid foams, the aggregating process of 2-6 retina cells was studied. Assuming the minimal perimeter for patterning cells to be the condition of stability patterns, the stable converged patterns we simulated in this work are the same as the experimental observations. More importantly, a new pattern of 6 cells was obtained which was found physically more stable than the other two reported by Hayashi and Carthew[1]. Aggregating perimeters of cells, i.e. the surface energy, showed a good linear fit with the cell numbers.

  4. The mechanism of pattern formation in the developing drosophila retina

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The biological patterning of the drosophila retina in vivo has striking resemblance to liquid bubbles, in which the surface mechanics due to N-cadherin within a sub-group of retina cells can be mimicked by surface tension. In this work, the aggregating patterns were reasonably simplified into 2D clusters consisting of 2—6 identical bubbles confined within a shrinking boundary. By using a hybrid fluid dy-namics model proposed for liquid foams, the aggregating process of 2―6 retina cells was studied. Assuming the minimal perimeter for patterning cells to be the condition of stability patterns, the stable converged patterns we simulated in this work are the same as the experimental observations. More importantly, a new pattern of 6 cells was obtained which was found physically more stable than the other two reported by Hayashi and Carthew[1]. Aggregating perimeters of cells, i.e. the surface energy, showed a good linear fit with the cell numbers.

  5. Primitive neuroectodermal tumor/Ewing sarcoma of the retina.

    Science.gov (United States)

    Grossniklaus, Hans E; Shehata, Bahig; Sorensen, Poul; Bergstrom, Chris; Hubbard, G Baker

    2012-07-01

    An 11-year-old boy underwent enucleation of his left eye for an intraocular tumor. Examination showed a small, round blue cell tumor arising in the peripheral retina near the ciliary body. Immunohistochemical stain results were positive for neuron-specific enolase, synaptophysin, cluster of differentiation 99 (CD99), Friend leukemia integration 1, and CD56. Ultrastructural findings included occasional intracytoplasmic dense core granules. Polymerase chain reaction of the tumor showed a Ewing sarcoma/Friend leukemia integration gene fusion product. The tumor was classified as a primitive neuroectodermal tumor/Ewing sarcoma of the retina and should be distinguished from retinoblastoma. To our knowledge, this is the first case of primary primitive neuroectodermal tumor of the retina.

  6. The architecture of functional interaction networks in the retina.

    Science.gov (United States)

    Ganmor, Elad; Segev, Ronen; Schneidman, Elad

    2011-02-23

    Sensory information is represented in the brain by the joint activity of large groups of neurons. Recent studies have shown that, although the number of possible activity patterns and underlying interactions is exponentially large, pairwise-based models give a surprisingly accurate description of neural population activity patterns. We explored the architecture of maximum entropy models of the functional interaction networks underlying the response of large populations of retinal ganglion cells, in adult tiger salamander retina, responding to natural and artificial stimuli. We found that we can further simplify these pairwise models by neglecting weak interaction terms or by relying on a small set of interaction strengths. Comparing network interactions under different visual stimuli, we show the existence of local network motifs in the interaction map of the retina. Our results demonstrate that the underlying interaction map of the retina is sparse and dominated by local overlapping interaction modules.

  7. A Possible Role of Neuroglobin in the Retina After Optic Nerve Injury: A Comparative Study of Zebrafish and Mouse Retina.

    Science.gov (United States)

    Sugitani, Kayo; Koriyama, Yoshiki; Ogai, Kazuhiro; Wakasugi, Keisuke; Kato, Satoru

    2016-01-01

    Neuroglobin (Ngb) is a new member of the family of heme proteins and is specifically expressed in neurons of the central and peripheral nervous systems in all vertebrates. In particular, the retina has a 100-fold higher concentration of Ngb than do other nervous tissues. The role of Ngb in the retina is yet to be clarified. Therefore, to understand the functional role of Ngb in the retina after optic nerve injury (ONI), we used two types of retina, from zebrafish and mice, which have permissible and non-permissible capacity for nerve regeneration after ONI, respectively. After ONI, the Ngb protein in zebrafish was upregulated in the amacrine cells within 3 days, whereas in the mouse retina, Ngb was downregulated in the retinal ganglion cells (RGCs) within 3 days. Zebrafish Ngb (z-Ngb) significantly enhanced neurite outgrowth in retinal explant culture. According to these results, we designed an overexpression experiment with the mouse Ngb (m-Ngb) gene in RGC-5 cells (retinal precursor cells). The excess of m-Ngb actually rescued RGC-5 cells under hypoxic conditions and significantly enhanced neurite outgrowth in cell culture. These data suggest that mammalian Ngb has positive neuroprotective and neuritogenic effects that induce nerve regeneration after ONI.

  8. Artificial retina: the multichannel processing of the mammalian retina achieved with a neuromorphic asynchronous light acquisition device.

    Science.gov (United States)

    Lorach, Henri; Benosman, Ryad; Marre, Olivier; Ieng, Sio-Hoi; Sahel, José A; Picaud, Serge

    2012-12-01

    Objective. Accurate modeling of retinal information processing remains a major challenge in retinal physiology with applications in visual rehabilitation and prosthetics. Most of the current artificial retinas are fed with static frame-based information, losing thereby the fundamental asynchronous features of biological vision. The objective of this work is to reproduce the spatial and temporal properties of the majority of ganglion cell (GC) types in the mammalian retina. Approach. Here, we combined an asynchronous event-based light sensor with a model pulling nonlinear subunits to reproduce the parallel filtering and temporal coding occurring in the retina. We fitted our model to physiological data and were able to reconstruct the spatio-temporal responses of the majority of GC types previously described in the mammalian retina (Roska et al 2006 J. Neurophysiol. 95 3810-22). Main results. Fitting of the temporal and spatial components of the response was achieved with high coefficients of determination (median R(2) = 0.972 and R(2) = 0.903, respectively). Our model provides an accurate temporal precision with a reliability of only few milliseconds-peak of the distribution at 5 ms-similar to biological retinas (Berry et al 1997 Proc. Natl Acad. Sci. USA 94 5411-16; Gollisch and Meister 2008 Science 319 1108-11). The spiking statistics of the model also followed physiological measurements (Fano factor: 0.331). Significance. This new asynchronous retinal model therefore opens new perspectives in the development of artificial visual systems and visual prosthetic devices.

  9. Effects of endothelin-1 eyedrops on the retina in rats.

    Science.gov (United States)

    Masuzawa, Koichi; Miyauchi, Takashi; Takanashi, Masakatsu; Ogata, Takehiro; Yamaguchi, Iwao; Goto, Katsutoshi

    2004-11-01

    Eye disorder accompanied with chronic retinal microvascular obstruction, such as diabetic retinopathy, exists in many diseases. However, it is difficult to produce this model experimentally in the animal eye. Endothelin-1 eyedrops were prepared in order to examine whether the eyedrops affect the rat retina and whether we can produce an obstruction model. Endothelin-1 eyedrops diluted by artificial tears in seven stages from 4 x 10(-5) M to 4 x 10(-11) M were arranged. We administered this solution three times a day in the left eye of male Sprague-Dawley rats. Artificial tears alone were applied to the right eye as a control vehicle. After 2 weeks, rats were sacrificed under anesthesia and the retinal tissues were isolated. As an index to the action of endothelin- 1 eyedrops to the retina, the expressions of endothelin-A (ETA) and endothelin-B (ETB) receptors in the retina were compared in both eyes. Frozen sections of the retina were immunostained to reveal the distribution of the ETA and ETB receptors. We also examined ETA and ETB mRNA expression by quantitative real-time polymerase chain reaction. As a result, the expressions of ETA and ETB receptors are reduced with both immunostaining and the mRNA levels in the left eye, in which endothelin-1 eyedrops were applied at 4 x 10(-5) M. It is suggested that endothelin-1 eyedrops affected the retina and the possibility of producing the experimental model of chronic microvascular obstruction in the rat retina.

  10. 激光共焦显微镜在阿米巴性角膜炎诊断中的应用%Diagnosis evaluation of Acanthamoeba keratitis with Heidelberg Retina Tomograph Ⅲ-RCM

    Institute of Scientific and Technical Information of China (English)

    张琛; 邓世靖; 王智群; 李然; 孙旭光

    2007-01-01

    目的 探讨激光共焦显微镜HRT3-RCM在阿米巴性角膜炎诊断中的应用价值.方法 对临床拟诊阿米巴性角膜炎患者9例(10眼)行HRT3-RCM检查,同时进行角膜刮片细胞学检查及阿米巴原虫培养.结果 9例患者中,HRT3-RCM显示7例角膜组织内阿米巴包囊为阳性,其中3例查到阿米巴滋养体,2例在角膜组织内查见真菌菌丝.包囊表现为圆形,双壁,高密度影像,直径15~20 μm;滋养体表现为不规则高密度影像,其中心或偏中心可见致密的核,直径25~40 μm.角膜刮片见阿米巴包囊7例,阿米巴培养阳性6例.结论 HRT3-RCM是利用激光作为光源的新一代共焦显微镜,分辨率更高,是一种快速无创的检查方法,可作为阿米巴性角膜炎早期病原学诊断以及治疗随访观察的重要辅助检查手段.

  11. 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.

  12. [Damage and functional recovery of the mouse retina after exposure to ionizing radiation and methylnitrosourea].

    Science.gov (United States)

    Vinogradova, Iu V; Tronov, V A; Liakhova, K N; Poplinskaia, V A; Ostrovskiĭ, M A

    2014-01-01

    The eye retina consists of terminally differentiated cells that have lost their ability to proliferate. The death of these cells leads tothe loss of sight. The mice retina is characterized by relatively high resistance to radiation, which is provided by its ability to repair damage caused by environmental factors. The aim of our work was to assess the damaging effect of ionizing radiation and methylnitrosourea (MNU) on the DNA structure in the mouse retina, the functional activity of the retina, and its ability to recover in vivo. The results confirm the ability of the mature retina to structural and functional recovery. Adapting influence of low dose chemical agent increases retina resistance to cytotoxic dose of genotoxicants and prevents degeneration of photoreceptor layer of the retina. The results show the possibility of neurohormesis effect in the mice retina after exposure to ionizing radiation and chemicals.

  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. Método de preparación del espécimen para evaluar la micromorfología de la interfase adhesiva resina-dentina con un microscopio electrónico de barrido

    Directory of Open Access Journals (Sweden)

    A Albaladejo

    Full Text Available La infiltración con resina de las fibras de colágeno desmineralizadas permiten la formación de una capa híbrida con tags de resina y ramas laterales, creando de esta manera, retenciones micromecánicas de la resina al substrato desmineralizado. Dichas retenciones son el principal mecanismo para la adhesión resina-dentina, siendo la penetración de la resina en la dentina intertubular, el factor de mayor importancia en la obtención de unas adecuadas fuerzas de adhesión. Uno de los instrumentos más usados para estudiar los mecanismos que envuelven el proceso de adhesión ha sido el microscopio electrónico de barrido (MEB. El principio del MEB se basa en imágenes tridimensionales que se construyen punto a punto y línea a línea desde los electrones secundarios. El objetivo de este estudio es describir la preparación de los espécimenes para evaluar la formación de la capa híbrida, los tags de resina y ramas laterales.

  15. Estudio de la reacción de curado del sistema éter diglicidílico del bisfenol-A (DGEBA y la dietilentriamina (DETA por calorimetría diferencial de barrido

    Directory of Open Access Journals (Sweden)

    González Garcia Filiberto

    2000-01-01

    Full Text Available La reacción de curado del sistema compuesto por el éter diglicidílico del bisfenol-A (DGEBA y la dietilentriamina (DETA fue estudiada por calorimetría diferencial de barrido (DSC. Diferentes expresiones cinéticas fueron encontradas por experimentos isotérmicos y dinámicos las que justifican cambios mecanísticos con la temperatura de cura. La cinética de la reacción cumple un segundo orden cinético con una energía de activación de 90 kJ mol-1 a altas temperaturas (mecanismo no catalítico. La cinética de la reacción a bajas temperaturas manifestó la existencia de dos mecanismos competitivos, se determinaron las constantes de velocidades de reacción a 60 y 70ºC y se encontró una energía de activación en el rango de 56.9 a 63.0 kJ mol¹, que está en perfecto acuerdo con la reportada a bajas temperaturas (mecanismo autocatalítico. También se muestra el diagrama de fases del sistema.

  16. A public confession: the retina trumpets its failed predictions.

    Science.gov (United States)

    Holy, Timothy E

    2007-09-20

    To compensate for delays of phototransduction, the retina anticipates the future by extrapolating the position of a moving object. But what if the object's motion changes, and the extrapolation is wrong? In this issue of Neuron, Schwartz and colleagues show that these prediction failures trigger a large burst of firing that helps to rapidly correct the neural representation of the object's new position.

  17. 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...

  18. The Virtual Retina: Is Good Educational Technology Always Strategic?

    Science.gov (United States)

    Dowie, Sandra

    Educational technology units must continually monitor their strategic plans to ensure that they are aligned with the realities of their institutions. Strategic dissonance occurs when previously successful strategies are no longer achieving the same positive outcomes. The Virtual Retina CD-ROM project is used in this paper as an example of…

  19. Functional architecture of the retina: development and disease.

    Science.gov (United States)

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

    2014-09-01

    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.

  20. A silicon retina that reproduces signals in the optic nerve.

    Science.gov (United States)

    Zaghloul, Kareem A; Boahen, Kwabena

    2006-12-01

    Prosthetic devices may someday be used to treat lesions of the central nervous system. Similar to neural circuits, these prosthetic devices should adapt their properties over time, independent of external control. Here we describe an artificial retina, constructed in silicon using single-transistor synaptic primitives, with two forms of locally controlled adaptation: luminance adaptation and contrast gain control. Both forms of adaptation rely on local modulation of synaptic strength, thus meeting the criteria of internal control. Our device is the first to reproduce the responses of the four major ganglion cell types that drive visual cortex, producing 3600 spiking outputs in total. We demonstrate how the responses of our device's ganglion cells compare to those measured from the mammalian retina. Replicating the retina's synaptic organization in our chip made it possible to perform these computations using a hundred times less energy than a microprocessor-and to match the mammalian retina in size and weight. With this level of efficiency and autonomy, it is now possible to develop fully implantable intraocular prostheses.

  1. Interleukin-1beta mediates ischemic injury in the rat retina.

    Science.gov (United States)

    Yoneda, S; Tanihara, H; Kido, N; Honda, Y; Goto, W; Hara, H; Miyawaki, N

    2001-11-01

    Two types of experiment were performed to examine the role of interleukin-1beta in ischemia-induced damage in the rat retina. In the in vivo study, enzyme-linked immunosorbent assay was used to investigate the expression of immunoreactive interleukin-1beta in the rat retina following a hypertension-induced ischemia/reperfusion, while the effect of a recombinant human interleukin-1 receptor antagonist or an anti-interleukin-1beta neutralizing antibody on the ischemia-induced damage was examined histologically. A transient increase in the expression of immunoreactive interleukin-1beta was observed in the retina 3-12 hr after reperfusion, and morphometric evaluation at 7 days after the ischemia showed a decrease in cell numbers in the ganglion cell layer and a decreased thickness of the inner plexiform layer with no change in the other retinal layers. Intravitreal injection of interleukin-1 receptor antagonist (1 or 10 ng per eye) or anti-interleukin-1beta antibody (50 or 500 ng per eye) 5 min before the onset of the ischemia reduced the damage. In the in vitro study, interleukin-1 receptor antagonist (500 ng ml(-1)) significantly reduced glutamate-induced neurotoxicity in rat cultured retinal neurons. These results suggest that interleukin-1 plays an important role in mediating ischemic and excitotoxic damage in the retina, and that interleukin-1 inhibitors may be therapeutically useful against neuronal injury caused by optic nerve or retinal diseases such as glaucoma and central retinal artery or vein occlusion.

  2. Gene expression profiles of the developing human retina

    Institute of Scientific and Technical Information of China (English)

    WANG Feng; LI Huiming; LIU Wenwen; XU Ping; HU Gengxi; CHENG Yidong; JIA Libin; HUANG Qian

    2004-01-01

    Retina is a multilayer and highly specialized tissue important in converting light into neural signals. In humans, the critical period for the formation of complex multiplayer structure takes place during embryogenesis between 12 and 28 weeks. The morphologic changes during retinal development in humans have been studied but little is known about the molecular events essential for the formation of the retina. To gain further insights into this process, cDNA microarrays containing 16361 human gene probes were used to measure the gene expression levels in retinas. Of the 16361 genes, 68.7%, 71.4% and 69.7% showed positive hybridization with cDNAs made from 12-16 week fetal, 22-26 week fetal and adult retinas. A total of 814 genes showed a minimum of 3-fold changes between the lowest and highest expression levels among three time points and among them, 106 genes had expression levels with the hybridization intensity above 100 at one or more time points. The clustering analysis suggested that the majority of differentially expressed genes were down-regulated during the retinal development. The differentially expressed genes were further classified according to functions of known genes, and were ranked in decreasing order according to frequency: development, differentiation, signal transduction, protein synthesis and translation, metabolism, DNA binding and transcription, DNA synthesis-repair-recombination, immuno-response, ion channel- transport, cell receptor, cytoskeleton, cell cycle, pro-oncogene, stress and apoptosis related genes. Among these 106 differentially expressed genes, 60 are already present in NEI retina cDNA or EST Databank but the remaining 46 genes are absent and thus identified as "function unknown". To validate gene expression data from the microarray, real-time RT-PCR was performed for 46 "function unknown" genes and 6 known retina specific expression genes, and β-actin was used as internal control. Twenty-seven of these genes showed very similar

  3. Impact of bronchopulmonary dysplasia on brain and retina.

    Science.gov (United States)

    Poon, Annie Wing Hoi; Ma, Emilie Xiao Hang; Vadivel, Arul; Jung, Suna; Khoja, Zehra; Stephens, Laurel; Thébaud, Bernard; Wintermark, Pia

    2016-04-15

    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.

  4. 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.

  5. Genomic Comparison of Non-Typhoidal Salmonella enterica Serovars Typhimurium, Enteritidis, Heidelberg, Hadar and Kentucky Isolates from Broiler Chickens.

    Directory of Open Access Journals (Sweden)

    Akhilesh S Dhanani

    Full Text Available Non-typhoidal Salmonella enterica serovars, associated with different foods including poultry products, are important causes of bacterial gastroenteritis worldwide. The colonization of the chicken gut by S. enterica could result in the contamination of the environment and food chain. The aim of this study was to compare the genomes of 25 S. enterica serovars isolated from broiler chicken farms to assess their intra- and inter-genetic variability, with a focus on virulence and antibiotic resistance characteristics.The genomes of 25 S. enterica isolates covering five serovars (ten Typhimurium including three monophasic 4,[5],12:i:, four Enteritidis, three Hadar, four Heidelberg and four Kentucky were sequenced. Most serovars were clustered in strongly supported phylogenetic clades, except for isolates of serovar Enteritidis that were scattered throughout the tree. Plasmids of varying sizes were detected in several isolates independently of serovars. Genes associated with the IncF plasmid and the IncI1 plasmid were identified in twelve and four isolates, respectively, while genes associated with the IncQ plasmid were found in one isolate. The presence of numerous genes associated with Salmonella pathogenicity islands (SPIs was also confirmed. Components of the type III and IV secretion systems (T3SS and T4SS varied in different isolates, which could explain in part, differences of their pathogenicity in humans and/or persistence in broilers. Conserved clusters of genes in the T3SS were detected that could be used in designing effective strategies (diagnostic, vaccination or treatments to combat Salmonella. Antibiotic resistance genes (CMY, aadA, ampC, florR, sul1, sulI, tetAB, and srtA and class I integrons were detected in resistant isolates while all isolates carried multidrug efflux pump systems regardless of their antibiotic susceptibility profile.This study showed that the predominant Salmonella serovars in broiler chickens harbor genes

  6. Phase space generation for proton and carbon ion beams for external users’ applications at the Heidelberg Ion Therapy Center

    Directory of Open Access Journals (Sweden)

    Thomas eTessonnier

    2016-01-01

    Full Text Available In the field of radiation therapy, accurate and robust dose calculation is required. For this purpose, precise modeling of the irradiation system and reliable computational platforms are needed. At the Heidelberg Ion Therapy Center (HIT, the beamline has been already modeled in the FLUKA Monte Carlo code. However, this model was kept confidential for disclosure reasons and was not available for any external team. The main goal of this study was to create efficiently phase space (PS files for proton and carbon ion beams, for all energies and foci available at HIT. PS are representing the characteristics of each particle recorded (charge, mass, energy, coordinates, direction cosines, generation at a certain position along the beam path. In order to achieve this goal, keeping a reasonable data size but maintaining the requested accuracy for the calculation, we developed a new approach of beam PS generation with the Monte-Carlo code FLUKA. The generated PS were obtained using an infinitely narrow beam and recording the desired quantities after the last element of the beamline, with a discrimination of primaries or secondaries. In this way, a unique PS can be used for each energy to accommodate the different foci by combining the narrow-beam scenario with a random sampling of its theoretical Gaussian beam in vacuum. PS can also reproduce the different patterns from the delivery system, when properly combined with the beam scanning information. MC simulations using PS have been compared to simulations including the full beamline geometry and have been found in very good agreement for several cases (depth dose distributions, lateral dose profiles, with relative dose differences below 0.5%. This approach has also been compared with measured data of ion beams with different energies and foci, resulting in a very satisfactory agreement. Hence, the proposed approach was able to fulfill the different requirements and has demonstrated its capability for

  7. Comparison of methods for quantitating Salmonella enterica Typhimurium and Heidelberg strain attachment to reusable plastic shipping container coupons and preliminary assessment of sanitizer efficacy.

    Science.gov (United States)

    Shi, Zhaohao; Baker, Christopher A; Lee, Sang In; Park, Si Hong; Kim, Sun Ae; Ricke, Steven C

    2016-09-01

    Salmonella serovars, one of the leading contributors to foodborne illness and are especially problematic for foods that are not cooked before consumption, such as fresh produce. The shipping containers that are used to transport and store fresh produce may play a role in cross contamination and subsequent illnesses. However, methods for quantitatively attached cells are somewhat variable. The overall goal of this study was to compare conventional plating with molecular methods for quantitating attached representative strains for Salmonella Typhimurium and Heidelberg on reusable plastic containers (RPC) coupons, respectively. We attached Salmonella enterica serovar Typhimurium ATCC 14028 and serovar Heidelberg SL486 (parent and an antibiotic resistant marker strain) to plastic coupons (2.54 cm(2)) derived from previously used shipping containers by growing for 72 h in tryptic soy broth. The impact of the concentration of sanitizer on log reductions between unsanitized and sanitized coupons was evaluated by exposing attached S. Typhimurium cells to 200 ppm and 200,000 ppm sodium hypochlorite (NaClO). Differences in sanitizer effectiveness between serovars were also evaluated with attached S. Typhimurium compared to attached S. Heidelberg populations after being exposed to 200 ppm peracetic acid (PAA). Treatment with NaClO caused an average of 2.73 ± 0.23 log CFU of S. Typhimurium per coupon removed with treatment at 200 ppm while 3.36 ± 0.54 log CFU were removed at 200,000 ppm. Treatment with PAA caused an average of 2.62 ± 0.15 log CFU removed for S. Typhimurium and 1.41 ± 0.17 log CFU for S. Heidelberg (parent) and 1.61 ± 0.08 log CFU (marker). Lastly, scanning electron microscopy (SEM) was used to visualize cell attachment and coupon surface topography. SEM images showed that remaining attached cell populations were visible even after sanitizer application. Conventional plating and qPCR yielded similar levels of enumerated bacterial populations

  8. Integration von Schulungsveranstaltungen der Bibliothek ins Curriculum - am Beispiel der Fakultät für Klinische Medizin Mannheim der Universität Heidelberg

    Directory of Open Access Journals (Sweden)

    Semmler-Schmetz, Martina

    2005-09-01

    Full Text Available In the winter semester 2004/05 the Faculty for Clinical Medicine Mannheim of Heidelberg University implemented the new Querschnittsschein "Epidemiology, medical biometrics and medical informatics" and integrated the first library instructional classes into its medical curriculum. In order to meet the new requirements the medical library established an instructional team that designed tailor-made courses for the student target group and put into practice the experiences gathered both in workshops (such as the continuing education course "Teaching Library" offered by the BIB in May 2004 and from the relevant literature. With a maximum participation of library staff almost all of the first clinical semster medical students finished three different instructional modules of the beginners and intermediate skill levels. Resonance to these courses was ascertained by evaluation forms completed by the participants immediately after the classes. The feedback was predominantly positive, and the members of the instructional team unanimously regarded the experiences made as new and inspiring. As a further development of the orientation and instruction classes integrated in the curriculum the medical library intends to participate in the navigation system LOTSE of the Universitäts- und Landesbibliothek Münster starting in the academic year 2005/06. Moreover, by then, one of the aforementioned classes is planned to be offered on the e-Learning platform ATHENA of Heidelberg University.

  9. [Balloon occlusion test of the internal carotid artery for evaluating resectability of blood vessel infiltrating cervical metastasis of advanced head and neck cancers--Heidelberg experience].

    Science.gov (United States)

    Dietz, A; von Kummer, R; Adams, H P; Kneip, M; Galito, P; Maier, H

    1993-11-01

    During the last two years 17 patients of the ENT-Department of the University of Heidelberg suffering from squamous-cell carcinomas of the head and neck underwent a balloon occlusion test of the internal carotid artery (ICA). The investigation was performed because of tumorous infiltration of the large cervical vessels. The balloon occlusion of the ICA was accomplished at the Department of Neuroradiology of the University of Heidelberg. While stopping bloodflow in the ICA of one side for 15-20 min, clinical, electrophysiological and Doppler sonographic monitoring was performed, to detect severe cerebral complications. The specific electrophysiological monitoring contained the detection of MSSEP's (median nerve stimulated somatosensorial evoked potentials) and TCMEP's (transcortical motor evoked potentials) during test occlusion. Balloon occlusion was not possible in three patients because of severe arteriosclerosis. Test occlusion had to be discontinued in three patients because of clinical complications (temporary amaurosis, orthostatic complications). Finally, seven patients showed contraindications during test occlusion for permanent occlusion of the ICA. Four patients had a permanent occlusion of the ICA after tumour resection. In two patients the ICA was removed without problems in test occlusion. The third patient underwent a permanent carotid occlusion because of bleeding complications (in spite of poor clinical tolerance of the test occlusion). In the fourth patient, only intraoperative neuromonitoring with MSSEP's was conducted before permanent carotid occlusion. All four patients did not show any neurological deficits after resection of the ICA. Neurophysiological monitoring played an important role in predicting cerebral complications after permanent occlusion of the ICA.

  10. 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.

  11. Optical Coherence Tomography and Raman Spectroscopy of the retina

    Energy Technology Data Exchange (ETDEWEB)

    Evans, J W; Zawadzki, R J; Liu, R; Chan, J; Lane, S; Werner, J S

    2009-01-16

    Imaging the structure and correlating it with the biochemical content of the retina holds promise for fundamental research and for clinical applications. Optical coherence tomography (OCT) is commonly used to image the 3D structure of the retina and while the added functionality of biochemical analysis afforded by Raman scattering could provide critical molecular signatures for clinicians and researchers, there are many technical challenges to combining these imaging modalities. We present an ex vivo OCT microscope combined with Raman spectroscopy capable of collecting morphological and molecular information about a sample simultaneously. The combined instrument will be used to investigate remaining technical challenges to combine these imaging modalities, such as the laser power levels needed to achieve a Raman signal above the noise level without damaging the sample.

  12. Experimental Study of Effect of Perfluorohexyloctane to Retina

    Institute of Scientific and Technical Information of China (English)

    Chunfang Li; Xiaoyan Ding; Lin Lu; Guanguang Feng; Huling Zheng

    2002-01-01

    Objective: To investigate the effect of perfluorohexvloctane to the retina of rabbit eyes.Methods: Perfluoroh-exyloctane (experimental group) or BSS(control group) intovitreous cavities of fifteen vitrectomized New Zealand white rabbits. A slit-lampbiomicroscope and an indirect ophthalmoscope were used to examine all the eyes pre- andpostoperation. Histopathological examination was performed after the rabbits weresacrificed. Results:Perfluorohexyloctane was injected into the vitreous cavity forming a single largeclear globe. No retinal detachment and cataract were found. The edema of outer plexiformlayer was significant, and then get thin, inner nuclear layer and ganglion cell bodies hada darker cytop: lasm and nucleoplasm. Conclusions: Perfluorohexyloctane in vitreous cavity had significant side effects on retinaAs a silicone solvent, it should be removed out completely after injection. We don′trecommend to use it as a new intraocular temponade.

  13. Using stem cells to mend the retina in ocular disease.

    Science.gov (United States)

    Bull, Natalie D; Martin, Keith R

    2009-11-01

    Retinal degenerative diseases are the leading cause of incurable blindness worldwide. Furthermore, existing pharmacological and surgical interventions are only partially effective in halting disease progression, thus adjunctive neuroprotective strategies are desperately needed to preserve vision. Stem cells appear to possess inherent neuroprotective abilities, at least in part by providing neurotrophic support to injured neurons. Advances in stem cell biology offer the hope of new therapies for a broad range of neurodegenerative conditions, including those of the retina. Experimental cell-mediated therapies also hint at the tantalizing possibility of achieving retinal neuronal replacement and regeneration, once cells are lost to the disease process. This article summarizes the latest advances in cell therapies for neuroprotection and regeneration in neurodegenerative pathologies of both the inner and outer retina.

  14. [Cataract extraction and blue light--impact on the retina].

    Science.gov (United States)

    Engelmann, K; Funk, R H

    2009-10-01

    This review focuses on the scientific background for the use of "yellow artificial lenses". We will address the fact that numerous basic scientific publications point to a rationale for this practice although it is often difficult to derive clear-cut evidence from clinical epidemiological studies for the preventive use of yellow artificial lenses. In the first part we refer to studies showing that especially the shortwave part of the visible spectrum of light can be harmful for the retina and optic nerve. For this, we have screened the literature for the major sources of radical production and for the targets of oxidative stress after impingement of "blue light" on the retina. Furthermore, we can show that many studies in cell and molecular biology, animal experiments and first clinical trials point to a preferential use of yellow-tinted lenses especially in the elderly and AMD patients.

  15. 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.

  16. Electroretinogram and Histopathologic Changes of the Retina after Methanol Intoxication

    Institute of Scientific and Technical Information of China (English)

    CHEN Jie-min; ZHU Guang-you; ZHAO Zi-qin; XIA Wen-tao

    2013-01-01

    In order to study the functional and structural alterations of the retina in SD rat model after methanol intoxication,35 rats were divided randomly into five groups administrated with saline,3-day high dose,7-day high dose,3-day low dose and 7-day low dose methanol separately.The retinal function of each group was assessed by flash electroretinogram (F-ERG) 3 and 7 days after methanol poisoning.The microstructure and ultrastructure of the retina were observed at the same time.The high-dose methanol intoxication induced irreversible retinal functional and structural damages 3 days after poisoning,which included prolonged latency and reduced amplitude of the Max-reaction of F-ERG.These injuries were aggravated 7 days after poisoning.Meanwhile,the latency and amplitude of the Cone-reaction of F-ERG were also affected 3 days after poisoning,but there were no further worsening tendency 7 days after poisoning.The retinal histological analysis showed cellular edema,heteromorphy and disarrangement,tissular loosen of the inner nuclear layer and photoreceptors layer.The mitochondrial damage began at the photoreceptors layer and developed further into the inner nuclear layer.The low-dose methanol intoxication only caused transient damage of the retina.Our results showed that the function and structure of the photoreceptor and inner nuclear layer were the primary target of methanol intoxication and that the rod cells were more sensitive to methanol intoxication than the cone cells.The mitochondrial damage developed from outer layer to inner layer of the retina.

  17. Analysis of bipolar and amacrine populations in marmoset retina.

    Science.gov (United States)

    Weltzien, Felix; Percival, Kumiko A; Martin, Paul R; Grünert, Ulrike

    2015-02-01

    About 15 parallel ganglion cell pathways transmit visual signals to the brain, but the interneuron (bipolar and amacrine) populations providing input to ganglion cells remain poorly understood in primate retina. We carried out a quantitative analysis of the inner nuclear layer in the retina of the marmoset (Callithrix jacchus). Vertical Vibratome sections along the horizontal meridian were processed with immunohistochemical markers. Image stacks were taken with a confocal microscope, and densities of cell populations were determined. The density of flat midget bipolar cells fell from 15,746 cells/mm(2) at 1 mm (8 deg) to 7,827 cells/mm(2) at 3 mm (25 deg). The rod bipolar cell density fell from 8,640 cells/mm(2) at 1 mm to 4,278 cells/mm(2) at 3 mm, but the ratio of the two bipolar cell types did not change with eccentricity. The amacrine cell density ranged from 30,000 cells/mm(2) at 8 deg to less than 15,000 cells/mm(2) at 25 deg, but throughout the retina, the ratio of glycinergic to γ-aminobutyric acid (GABA)ergic to amacrine cells remained relatively constant. The fractions of rod bipolar, cone bipolar, amacrine, Müller, and horizontal cells of all cells in the inner nuclear layer were comparable in central and peripheral retina. Marmosets had lower proportions of midget bipolar and rod bipolar in comparison with macaque. These differences were correlated with differences in rod and cone densities between the two species and did not reflect fundamental differences in the wiring between the two species.

  18. Immunohistochemical and calcium imaging methods in wholemount rat retina.

    Science.gov (United States)

    Sargoy, Allison; Barnes, Steven; Brecha, Nicholas C; Pérez De Sevilla Müller, Luis

    2014-10-13

    In this paper we describe the tools, reagents, and the practical steps that are needed for: 1) successful preparation of wholemount retinas for immunohistochemistry and, 2) calcium imaging for the study of voltage gated calcium channel (VGCC) mediated calcium signaling in retinal ganglion cells. The calcium imaging method we describe circumvents issues concerning non-specific loading of displaced amacrine cells in the ganglion cell layer.

  19. Immunohistochemical and Calcium Imaging Methods in Wholemount Rat Retina

    OpenAIRE

    SARGOY, ALLISON; Barnes, Steven; Brecha, Nicholas C.; De Sevilla Müller, Luis Pérez

    2014-01-01

    In this paper we describe the tools, reagents, and the practical steps that are needed for: 1) successful preparation of wholemount retinas for immunohistochemistry and, 2) calcium imaging for the study of voltage gated calcium channel (VGCC) mediated calcium signaling in retinal ganglion cells. The calcium imaging method we describe circumvents issues concerning non-specific loading of displaced amacrine cells in the ganglion cell layer.

  20. Genetic variations strongly influence phenotypic outcome in the mouse retina.

    Directory of Open Access Journals (Sweden)

    Austin S Jelcick

    Full Text Available Variation in genetic background can significantly influence the phenotypic outcome of both disease and non-disease associated traits. Additionally, differences in temporal and strain specific gene expression can also contribute to phenotypes in the mammalian retina. This is the first report of microarray based cross-strain analysis of gene expression in the retina investigating genetic background effects. Microarray analyses were performed on retinas from the following mouse strains: C57BL6/J, AKR/J, CAST/EiJ, and NOD.NON-H2(-nb1 at embryonic day 18.5 (E18.5 and postnatal day 30.5 (P30.5. Over 3000 differentially expressed genes were identified between strains and developmental stages. Differential gene expression was confirmed by qRT-PCR, Western blot, and immunohistochemistry. Three major gene networks were identified that function to regulate retinal or photoreceptor development, visual perception, cellular transport, and signal transduction. Many of the genes in these networks are implicated in retinal diseases such as bradyopsia, night-blindness, and cone-rod dystrophy. Our analysis revealed strain specific variations in cone photoreceptor cell patterning and retinal function. This study highlights the substantial impact of genetic background on both development and function of the retina and the level of gene expression differences tolerated for normal retinal function. These strain specific genetic variations may also be present in other tissues. In addition, this study will provide valuable insight for the development of more accurate models for human retinal diseases.

  1. Age related macular degeneration and drusen: neuroinflammation in the retina.

    Science.gov (United States)

    Buschini, Elisa; Piras, Antonio; Nuzzi, Raffaele; Vercelli, Alessandro

    2011-09-15

    Inflammation protects from dangerous stimuli, restoring normal tissue homeostasis. Inflammatory response in the nervous system ("neuroinflammation") has distinct features, which are shared in several diseases. The retina is an immune-privileged site, and the tight balance of immune reaction can be disrupted and lead to age-related macular disease (AMD) and to its peculiar sign, the druse. Excessive activation of inflammatory and immunological cascade with subsequent induction of damage, persistent activation of resident immune cells, accumulation of byproducts that exceeds the normal capacity of clearance giving origin to a chronic local inflammation, alterations in the activation of the complement system, infiltration of macrophages, T-lymphocytes and mast-cells from the bloodstream, participate in the mechanisms which originate the drusen. In addition, aging of the retina and AMD involve also para-inflammation, by which immune cells react to persistent stressful stimuli generating low-grade inflammation, aimed at restoring function and maintaining tissue homeostasis by varying the set point in relation to the new altered conditions. This mechanism is also seen in the normal aging retina, but, in the presence of noxious stimuli as in AMD, it can become chronic and have an adverse outcome. Finally, autophagy may provide new insights to understand AMD pathology, due to its contribution in the removal of defective proteins. Therefore, the AMD retina can represent a valuable model to study neuroinflammation, its mechanisms and therapy in a restricted and controllable environment. Targeting these pathways could represent a new way to treat and prevent both exudative and dry forms of AMD.

  2. EFFECTS OF TETRAMETHYLPYRAZINE ON RETINA OF RABBITS WITHEXPERIMENTAL GLAUCOMA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective To observe the effects of tetramethyipyrazine(TMP) on retina to find out whether it can protect retina from glaucomatous damage. Methods Twenty-four rabbits were randomly divided into four groups. One eye of each rabbit was model eye induced by 2% methylcellulous, and the other was control eye. Normal saline, TMP, timolol and a combination of timolol and TMP were administrated to group A, B, C and D respectively. At the end of 4th week, eyes were excavated for light and electron microscopic study. Results The numbers of ganglion cells (P <0. 01) and bipolar cells (P <0. 01) in model eye were different significantly between group A and B. In group A, the model eye ganglion cells were karyopyknosis, chromatin margination and nuclear membrane rupture; some in ner nuclear cells dcveloped marked lytic changes; outer segment appeared disorganized; but group B changed slight ly. Conclusion The results suggest that TMP may protect retina from glaucomatous damage.

  3. 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.

  4. In vivo intrinsic optical signal imaging of mouse retinas

    Science.gov (United States)

    Wang, Benquan; Yao, Xincheng

    2016-03-01

    Intrinsic optical signal (IOS) imaging is a promising noninvasive method for advanced study and diagnosis of eye diseases. Before pursuing clinical applications, more IOS studies employing animal models are necessary to establish the relationship between IOS distortions and eye diseases. Ample mouse models are available for investigating the relationship between IOS distortions and eye diseases. However, in vivo IOS imaging of mouse retinas is challenging due to the small ocular lens (compared to frog eyes) and inevitable eye movements. We report here in vivo IOS imaging of mouse retinas using a custom-designed functional OCT. The OCT system provided high resolution (3 μm) and high speed (up to 500 frames/s) imaging of mouse retinas. An animal holder equipped with a custom designed ear bar and bite bar was used to minimize eye movement due to breathing and heartbeats. Residual eye movement in OCT images was further compensated by accurate image registration. Dynamic OCT imaging revealed rapid IOSs from photoreceptor outer segments immediately (IOS changes were also observed from inner retinal layers with delayed time courses compared to that of photoreceptor IOSs.

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

    Directory of Open Access Journals (Sweden)

    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

  6. Sobre la génesis del orden psiquiátrico en la posguerra española. La implantación de la psiquiatría de Heidelberg en España.

    Directory of Open Access Journals (Sweden)

    Ángel González de Pablo

    1987-01-01

    Full Text Available Se ofrece un análisis de la influencia de la psiquiatría de Heidelberg sobre la española. Dicha relación queda sistematizada en tres etapas: fase de comienzo (influencia de Kraepelin, fase de asentamiento (influencia de Jaspers y Schneider y fase de expansión y declive (influencia de la nueva escuela de Heidelberg. El trabajo se completa con algunas consideraciones epistemológicas sobre el desarrollo de la medicina en general y de la psiquiatría en particular.

  7. The estrogenic retina: The potential contribution to healthy aging and age-related neurodegenerative diseases of the retina.

    Science.gov (United States)

    Cascio, Caterina; Deidda, Irene; Russo, Domenica; Guarneri, Patrizia

    2015-11-01

    These last two decades have seen an explosion of clinical and epidemiological research, and basic research devoted to envisage the influence of gender and hormonal fluctuations in the retina/ocular diseases. Particular attention has been paid to age-related disorders because of the overlap of endocrine and neuronal dysfunction with aging. Hormonal withdrawal has been considered among risk factors for diseases such as glaucoma, diabetic retinopathy and age-related macular disease (AMD), as well as, for Alzheimer's disease, Parkinson's disease, or other neurodegenerative disorders. Sex hormones and aging have been also suggested to drive the incidence of ocular surface diseases such as dry eye and cataract. Hormone therapy has been approached in several clinical trials. The discovery that the retina is another CNS tissue synthesizing neurosteroids, among which neuroactive steroids, has favored these studies. However, the puzzling data emerged from clinical, epidemiological and experimental studies have added several dimensions of complexity; the current landscape is inherently limited to the weak information on the influence and interdependence of endocrine, paracrine and autocrine regulation in the retina, but also in the brain. Focusing on the estrogenic retina, we here review our knowledge on local 17β-oestradiol (E2) synthesis from cholesterol-based neurosteroidogenic path and testosterone aromatization, and presence of estrogen receptors (ERα and ERβ). The first cholesterol-limiting step and the final aromatase-limiting step are discussed as possible check-points of retinal functional/dysfunctional E2. Possible E2 neuroprotection is commented as a group of experimental evidence on excitotoxic and oxidative retinal paradigms, and models of retinal neurodegenerative diseases, such as glaucoma, diabetic retinopathy and AMD. These findings may provide a framework to support clinical studies, although further basic research is needed.

  8. Brain derived neurotrophic factor in the retina of the teleost N. furzeri.

    Science.gov (United States)

    Gatta, Claudia; Castaldo, Luciana; Cellerino, Alessandro; de Girolamo, Paolo; Lucini, Carla; D'Angelo, Livia

    2014-07-01

    BDNF plays an important role in the development and maintenance of visual circuitries in the retina and brain visual centers. In adulthood, BDNF signaling is involved in neural protection and regeneration of retina. In this survey, we investigated the expression of BDNF in the retina of adult Nothobranchius furzeri, a teleost fish employed for age research. After describing the retina of N. furzeri and confirming that the structure is organized in layers as in all vertebrates, we have studied the localization of BDNF mRNA and protein throughout the retinal layers. BDNF mRNA is detectable in all layers, whereas the protein is lacking in the photoreceptors. The occurrence of BDNF provides new insights on its role in the retina, particularly in view of age-related disease of retina.

  9. 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

    in the rodent retina, but its presence in the primate retina has not yet been demonstrated. The aim of this study was twofold: 1) to characterize the distribution patterns of CB2R in the monkey retina and compare this distribution with that previously reported for CB1R and 2) to resolve the controversy...... on the presence of CB2R in the neural component of the retina. We therefore thoroughly examined the cellular localization of CB2R in the vervet monkey (Chlorocebus sabeus) retina, using confocal microscopy. Our results demonstrate that CB2R, like CB1R, is present throughout the retinal layers, but with striking...... but exclusively in the retinal glia, whereas CB1R is expressed only in the neuroretina. These results extend our knowledge on the expression and distribution of cannabinoid receptors in the monkey retina, although further experiments are still needed to clarify their role in retinal functions....

  10. Localization and regulation of dopamine receptor D4 expression in the adult and developing rat retina

    DEFF Research Database (Denmark)

    Klitten, Laura L; Rath, Martin F; Coon, Steven L

    2008-01-01

    Levels of dopamine and melatonin exhibit diurnal rhythms in the rat retina. Dopamine is high during daytime adapting the retina to light, whereas melatonin is high during nighttime participating in the adaptation of the retina to low light intensities. Dopamine inhibits the synthesis of melatonin....... The sharp increase of Drd4 expression at a specific postnatal time suggests that dopamine is involved in retinal development....

  11. Simulation and performance of an artificial retina for 40 MHz track reconstruction

    OpenAIRE

    2014-01-01

    We present the results of a detailed simulation of the artificial retina pattern-recognition algorithm, designed to reconstruct events with hundreds of charged-particle tracks in pixel and silicon detectors at LHCb with LHC crossing frequency of $40\\,\\rm MHz$. Performances of the artificial retina algorithm are assessed using the official Monte Carlo samples of the LHCb experiment. We found performances for the retina pattern-recognition algorithm comparable with the full LHCb reconstruction ...

  12. Circadian organization of the rodent retina involves strongly coupled, layer-specific oscillators.

    Science.gov (United States)

    Jaeger, Catherine; Sandu, Cristina; Malan, André; Mellac, Katell; Hicks, David; Felder-Schmittbuhl, Marie-Paule

    2015-04-01

    Rhythmic physiology is central to retinal function and survival and adapts vision to daily light intensity changes. Mammalian retina rhythmically releases melatonin when cultured under constant conditions, and the occurrence of clock gene [e.g., Period (Per)] expression has been shown for most cellular layers. However, contribution of the distinct layers to genesis of circadian rhythms within the retina is still debated. To characterize their endogenous oscillatory capacity and their communication at the whole-tissue level, we used a vibratome-based method to isolate individual or paired retina cellular layers from the mPer2(Luc) mouse and Per1-luciferase (Per1-Luc) rat, and real-time recorded bioluminescence. We report that each layer of the mouse retina harbors a self-sustained oscillator whose period is significantly longer (∼ 26 hours) than in whole-retina explants (∼ 22.9 hours), indicating that the period is correlated with the degree of coupling. Accordingly, the maximal period (∼ 29 hours) is reached upon complete enzymatic dissociation of the retina. By using pharmacological approaches, we demonstrate that connection between retina oscillators involves gap junctions but only minor contribution from the main retina neurochemicals. Taken together with results from Per1-Luc rats, these data show that mammalian retina consists of a network of layer-specific oscillators whose period is determined by their connectivity.

  13. Tryptophan hydroxylase and serotonin receptor 1A expression in the retina of the sea lamprey.

    Science.gov (United States)

    Cornide-Petronio, María Eugenia; Anadón, Ramón; Barreiro-Iglesias, Antón; Rodicio, María Celina

    2015-06-01

    The dual development of the retina of lampreys is exceptional among vertebrates and offers an interesting EvoDevo (evolutionary developmental biology) model for understanding the origin and evolution of the vertebrate retina. Only a single type of photoreceptor, ganglion cell and bipolar cell are present in the early-differentiated central retina of lamprey prolarvae. A lateral retina appears later in medium-sized larvae (about 3 years after hatching in the sea lamprey), growing and remaining largely neuroblastic until metamorphosis. In this lateral retina, only ganglion cells and optic fibers differentiate in larvae, whereas differentiation of amacrine, horizontal, photoreceptor and bipolar cells mainly takes place during metamorphosis, which gives rise to the adult retina. Serotonin (5-hydroxytryptamine, 5-HT) is a neurotransmitter found in the retina of vertebrates whose synthesis is mediated by the rate-limiting enzyme tryptophan hydroxylase (TPH). TPH is also the first enzyme in the biosynthetic pathways of melatonin in photoreceptor cells. The serotonin 1A receptor (5-HT1A) is a major determinant of the activity of both serotonergic cells and their targets due to its pre- and post-synaptic location. Here, we report the developmental pattern of expression of tph and 5-ht1a transcripts in the sea lamprey retina by means of in situ hybridization. In larvae, strong tph mRNA signal was observed in photoreceptors and putative ganglion cells of the central retina, and in some neuroblasts of the lateral retina. In adults, strong tph expression was observed in bipolar, amacrine and ganglion cells and in photoreceptors. In the prolarval (central) retina, all the differentiated retinal cells expressed 5-ht1a transcripts, which were not observed in undifferentiated cells. In larvae, photoreceptors, bipolar cells and ganglion cells in the central retina, and neuroblasts in the lateral retina, showed 5-ht1a expression. In the adult retina, expression of 5-ht1a transcript

  14. 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.

  15. Descripción de la morfología externa por microscopia de luz y electrónica de barrido de Megninia ginglymura, Megnin, 1877 en faisán de collar (Phasianus torquatus), en un criadero de Corrientes, Argentina

    OpenAIRE

    A. Santa Cruz ; M. C. Agüero ; J. A. González; J.A Comolli ; D. Cayo; J. P. Roux.-

    2008-01-01

    El objetivo de este trabajo es reportar el primer hallazgo de Megninia ginglymura, Megnin, 1877 (Arthropoda, Arachnida, Acari, Astigmata, Analgidae), en faisán de collar (Phasianus torquatus) y describir algunos caracteres morfológicos externos a través imágenes obtenidas con microscopios de luz y microscopio electrónico de barrido. La investigación se llevó a cabo en un criadero ubicado en la localidad del Ingenio Santa Ana de la ciudad de Corrientes, Latitud 27º 26´ 01, Longitud 58º 37´ 21....

  16. Effect of dietary fatty acid intake on prospective weight change in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition

    DEFF Research Database (Denmark)

    Nimptsch, Katharina; Berg-Beckhoff, Gabi; Linseisen, Jakob

    2010-01-01

    OBJECTIVE: To evaluate the association between fatty acid (alpha-linolenic acid (ALA), EPA, DHA, palmitic, stearic, oleic, linoleic and arachidonic acids) intake and prospective weight change in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition. DESIGN......) and categorised into four groups (weight loss, or =2.5 to or =7.5%/5 years). Energy-adjusted dietary fatty acid intake data were estimated from the FFQ completed at baseline. Multivariate linear regression models as well as multinomial logistic regression analyses (carbohydrate replacement models) were conducted....... RESULTS: Stearic acid intake was linearly associated with weight gain (P acid intake, significantly so in women. In multinomial models, women in the highest tertile of ALA and stearic acid intake showed increased OR (95 % CI...

  17. Pbx homeodomain proteins pattern both the zebrafish retina and tectum

    Directory of Open Access Journals (Sweden)

    Stout Jennifer

    2007-07-01

    Full Text Available Abstract Background Pbx genes encode TALE class homeodomain transcription factors that pattern the developing neural tube, pancreas, and blood. Within the hindbrain, Pbx cooperates with Hox proteins to regulate rhombomere segment identity. Pbx cooperates with Eng to regulate midbrain-hindbrain boundary maintenance, and with MyoD to control fast muscle cell differentiation. Although previous results have demonstrated that Pbx is required for proper eye size, functions in regulating retinal cell identity and patterning have not yet been examined. Results Analysis of retinal ganglion cell axon pathfinding and outgrowth in pbx2/4 null embryos demonstrated a key role for pbx genes in regulating neural cell behavior. To identify Pbx-dependent genes involved in regulating retino-tectal pathfinding, we conducted a microarray screen for Pbx-dependent transcripts in zebrafish, and detected genes that are specifically expressed in the eye and tectum. A subset of Pbx-dependent retinal transcripts delineate specific domains in the dorso-temporal lobe of the developing retina. Furthermore, we determined that some Pbx-dependent transcripts also require Meis1 and Gdf6a function. Since gdf6a expression is also dependent on Pbx, we propose a model in which Pbx proteins regulate expression of the growth factor gdf6a, which in turn regulates patterning of the dorso-temporal lobe of the retina. This, in concert with aberrant tectal patterning in pbx2/4 null embryos, may lead to the observed defects in RGC outgrowth. Conclusion These data define a novel role for Pbx in patterning the vertebrate retina and tectum in a manner required for proper retinal ganglion cell axon outgrowth.

  18. Patterns of rod proliferation in deep-sea fish retinae.

    Science.gov (United States)

    Fröhlich, E; Negishi, K; Wagner, H J

    1995-07-01

    In a sample of 37 species of deep-sea fish species from the sea floor of the Porcupine Seabight and the Gobal spur (North Atlantic) we investigated the overall structure of the retina with special respect for the organization of rods, their length and their arrangement in multiple banks. Using an immunocytochemical marker for cell proliferation (PCNA) we studied the mechanisms of rod proliferation, and, by means of serial section reconstruction followed their integration into the existing population of rods. Furthermore, in three different species we have observed growth related changes in retinal thickness, rod density and proliferation activity. We found evidence for two different principles for the organization of rods in these deep-sea fish retinae. In the first group of species represented by Nematonurus armatus and Coryphaenoides guentheri we found rods to be rather short (20-30 microns) and arranged in three and more banks. In these species rod proliferation occurred in a single band of cells immediately vitread of the external limiting membrane, thus showing a high degree of spatial and temporal order. In these species, young rods are inserted just sclerad of the external limiting membrane and the older outer segments pushed away from the incoming light towards the back of the eye. This may be linked to a progressive loss of function of the older rods and might represent an alternative mechanism to the disk shedding in other vertebrates. In the second population (e.g. Conocara macroptera, Alepocephalus agassizii) we observed considerably longer rod outer segments (60-80 microns) forming no more than two layers. These retinae had rod precursors arranged in disseminated clusters throughout the outer nuclear layer indicating the lack of clear spatio-temporal order in mitotic activity along with a more statistical pattern of integration of the newly formed outer segments. In our sample of species both populations were of about equal size suggesting that the two

  19. First Results of an "Artificial Retina" Processor Prototype

    Science.gov (United States)

    Cenci, Riccardo; Bedeschi, Franco; Marino, Pietro; Morello, Michael J.; Ninci, Daniele; Piucci, Alessio; Punzi, Giovanni; Ristori, Luciano; Spinella, Franco; Stracka, Simone; Tonelli, Diego; Walsh, John

    2016-11-01

    We report on the performance of a specialized processor capable of reconstructing charged particle tracks in a realistic LHC silicon tracker detector, at the same speed of the readout and with sub-microsecond latency. The processor is based on an innovative pattern-recognition algorithm, called "artificial retina algorithm", inspired from the vision system of mammals. A prototype of the processor has been designed, simulated, and implemented on Tel62 boards equipped with high-bandwidth Altera Stratix III FPGA devices. The prototype is the first step towards a real-time track reconstruction device aimed at processing complex events of high-luminosity LHC experiments at 40 MHz crossing rate.

  20. [Ketamine-induced ultrastructural changes in the retina].

    Science.gov (United States)

    Magdolina, A

    1978-10-01

    Alterations of the retina caused by ketamin were studied in experiment. After a 60-minutes monoanaesthesia with ketamin ultrastructural changes were observed on the inner members of receptor cells, in the three nuclear layers and in the layer of nerve fibres. Severe damage to the structure of the Müller's glial cells providing nutrition to neural-elements was also revealed. Three days after the anaesthesia beside the regression of these alterations, glycogen deposits could be seen in the Müller's cells. This phenomenon and some side effects caused by ketamin can be explained by increased utilization of oxygen and relative hypoxia.

  1. 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.

  2. Ischemia-induced spreading depolarization in the retina.

    Science.gov (United States)

    Srienc, Anja I; Biesecker, Kyle R; Shimoda, Angela M; Kur, Joanna; Newman, Eric A

    2016-09-01

    Cortical spreading depolarization is a metabolically costly phenomenon that affects the brain in both health and disease. Following severe stroke, subarachnoid hemorrhage, or traumatic brain injury, cortical spreading depolarization exacerbates tissue damage and enlarges infarct volumes. It is not known, however, whether spreading depolarization also occurs in the retina in vivo. We report now that spreading depolarization episodes are generated in the in vivo rat retina following retinal vessel occlusion produced by photothrombosis. The properties of retinal spreading depolarization are similar to those of cortical spreading depolarization. Retinal spreading depolarization waves propagate at a velocity of 3.0 ± 0.1 mm/min and are associated with a negative shift in direct current potential, a transient cessation of neuronal spiking, arteriole constriction, and a decrease in tissue O2 tension. The frequency of retinal spreading depolarization generation in vivo is reduced by administration of the NMDA antagonist MK-801 and the 5-HT(1D) agonist sumatriptan. Branch retinal vein occlusion is a leading cause of vision loss from vascular disease. Our results suggest that retinal spreading depolarization could contribute to retinal damage in acute retinal ischemia and demonstrate that pharmacological agents can reduce retinal spreading depolarization frequency after retinal vessel occlusion. Blocking retinal spreading depolarization generation may represent a therapeutic strategy for preserving vision in branch retinal vein occlusion patients.

  3. Sector mapping method for 3D detached retina visualization.

    Science.gov (United States)

    Zhai, Yi-Ran; Zhao, Yong; Zhong, Jie; Li, Ke; Lu, Cui-Xin; Zhang, Bing

    2016-10-01

    A new sphere-mapping algorithm called sector mapping is introduced to map sector images to the sphere of an eyeball. The proposed sector-mapping algorithm is evaluated and compared with the plane-mapping algorithm adopted in previous work. A simulation that maps an image of concentric circles to the sphere of the eyeball and an analysis of the difference in distance between neighboring points in a plane and sector were used to compare the two mapping algorithms. A three-dimensional model of a whole retina with clear retinal detachment was generated using the Visualization Toolkit software. A comparison of the mapping results shows that the central part of the retina near the optic disc is stretched and its edges are compressed when the plane-mapping algorithm is used. A better mapping result is obtained by the sector-mapping algorithm than by the plane-mapping algorithm in both the simulation results and real clinical retinal detachment three-dimensional reconstruction.

  4. 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.

  5. TRP channel gene expression in the mouse retina.

    Science.gov (United States)

    Gilliam, Jared C; Wensel, Theodore G

    2011-12-08

    In order to identify candidate cation channels important for retinal physiology, 28 TRP channel genes were surveyed for expression in the mouse retina. Transcripts for all TRP channels were detected by RT-PCR and sequencing. Northern blotting revealed that mRNAs for 12 TRP channel genes are enriched in the retina. The strongest signals were observed for TRPC1, TRPC3, TRPM1, TRPM3, and TRPML1, and clear signals were obtained for TRPC4, TRPM7, TRPP2, TRPV2, and TRPV4. In situ hybridization and immunofluorescence revealed widespread expression throughout multiple retinal layers for TRPC1, TRPC3, TRPC4, TRPML1, PKD1, and TRPP2. Striking localization of enhanced mRNA expression was observed for TRPC1 in the photoreceptor inner segment layer, for TRPM1 in the inner nuclear layer (INL), for TRPM3 in the INL, and for TRPML1 in the outer plexiform and nuclear layers. Strong immunofluorescence signal in cone outer segments was observed for TRPM7 and TRPP2. TRPC5 immunostaining was largely confined to INL cells immediately adjacent to the inner plexiform layer. TRPV2 antibodies stained photoreceptor axons in the outer plexiform layer. Expression of TRPM1 splice variants was strong in the ciliary body, whereas TRPM3 was strongly expressed in the retinal pigmented epithelium.

  6. Adenovirally Delivered Brain-derived Neurotrophic Factor to Rat Retina

    Institute of Scientific and Technical Information of China (English)

    Xu Hou; Dan Hu; Yannian Hui

    2004-01-01

    Purpose: To study the expression of brain-derived neurotrophic factor (BDNF) in the rat retina delivered by adenovirus.Methods: Adenovirus with BDNF gene was injected into the vitreous. Gene expression was detected by immunofluorescence staining, and quantitative analysis was performed after injury and transfection by Enzyme-linked immunosorbent assay (ELISA).Results: The positive cells can be seen on the 3rd day and last 4 weeks by immunofluorescence staining. Positive cells in the control group were fewer than those in the transfection group or the fluorescence intensity was lower at every time point. Quantitative analysis showed that the expression of BDNF groups was higher than that of the control group at every time point(P < 0.01 ), and that of the injured group without transfection was higher than that of the control group on the 3rd day and the 7th day (P < 0.01 ).Conclusion: Efficient and stable transfer of BDNF gene could be achieved by adenovirus delivery into the retina of rats. Injury can promote the expression of BDNF in early period.

  7. A method to determine the mechanical properties of the retina based on an experiment in vivo.

    Science.gov (United States)

    Qian, Xiuqing; Zhang, Kunya; Liu, Zhicheng

    2015-01-01

    A method is proposed to determine the mechanical properties of retina based on in vivo experiments and numerical simulations. First, saline water was injected into the anterior chamber of the right eye of a cat to cause acute high intraocular pressure. After the eye was scanned using optical coherence tomography under different acute high intraocular pressures, the images of the retina in vivo were obtained and the thickness of the retina was calculated. Then, the three-dimensional structure of the optic nerve head including the retina and the choroid were reconstructed using image processing technology. Three different material models for the retina and the choroid were taken and the finite element models of the optic nerve head were constructed. Finally, an inverse method was proposed to determine the parameters of a constitutive model of the retina and of the choroid simultaneously. The results showed that the deformation of the retina can be properly simulated taking into consideration the nonlinear elastic properties of the retina and of the choroid.

  8. 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.

  9. Aging Leads to Elevation of O-GlcNAcylation and Disruption of Mitochondrial Homeostasis in Retina

    Directory of Open Access Journals (Sweden)

    Lin Zhao

    2014-01-01

    Full Text Available Retina is particularly susceptible to aging as oxidative damage accumulates within retina, leading to age-related retinal dysfunction or even visual loss. However, the underlying mechanisms still remain obscure and effective therapeutic strategy is urgently in need. Here, we quested for the answer particularly focusing on mitochondrial homeostasis and O-GlcNAcylation in rat retina. By comparing expression of electron transfer chain complexes and key factors in mitochondrial biogenesis and dynamics in retinas of aged and young Sprague-Dawley rats, we found that mitochondrial Complex I, II, IV and V were increased in aged retina with decreased mtTFA and Mfn2. Also, we noticed that p38 and JNK of MAPK signaling were substantially more activated in aged retina, suggesting stress induction. In addition, we found that pan-O-GlcNAcylation was remarkably stronger with lower OGA expression in aged retina. To further elucidate the roles of Mfn2 and O-GlcNAcylation, we employed ARPE-19 cells and found that ATP production, oxygen consumption, and mitochondrial membrane potential were reduced and ROS level was increased by Mfn2 knockdown, while treating with PUGNAc or UDP-GlcNAc heightened oxygen consumption and reduced ROS. Our results suggest disrupted mitochondrial homeostasis may increase oxidative stress; yet enhanced O-GlcNAcylation might defend against oxidative stress and promote mitochondrial respiration in aged retina.

  10. MPP1 links the Usher protein network and the Crumbs protein complex in the retina.

    NARCIS (Netherlands)

    Gosens, I.; Wijk, E. van; Kersten, F.F.J.; Krieger, E.; Zwaag, B. van der; Marker, T.; Letteboer, S.J.F.; Dusseljee, S.; Peters, T.; Spierenburg, H.A.; Punte, I.M.; Wolfrum, U.; Cremers, F.P.M.; Kremer, H.; Roepman, R.

    2007-01-01

    The highly ordered distribution of neurons is an essential feature of a functional mammalian retina. Disruptions in the apico-basal polarity complexes at the outer limiting membrane (OLM) of the retina are associated with retinal patterning defects in vertebrates. We have analyzed the binding repert

  11. In vivo cellular visualization of the human retina using optical coherence tomography and adaptive optics

    Energy Technology Data Exchange (ETDEWEB)

    Olivier, S S; Jones, S M; Chen, D C; Zawadzki, R J; Choi, S S; Laut, S P; Werner, J S

    2006-01-05

    Optical coherence tomography (OCT) sees the human retina sharply with adaptive optics. In vivo cellular visualization of the human retina at micrometer-scale resolution is possible by enhancing Fourier-domain optical-coherence tomography with adaptive optics, which compensate for the eye's optical aberrations.

  12. Effects of Aging and Anatomic Location on Gene Expression in Human Retina

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    Hui eCai

    2012-05-01

    Full Text Available Objective: To determine the effects of age and topographic location on gene expression in human neural retina.Methods: Macular and peripheral neural retina RNA were isolated from human donor eyes for DNA microarray and quantitative RT-PCR analyses.Results: Total RNA integrity from human donors was preserved. Hierarchical clustering analysis demonstrates that the gene expression profiles of young, old, macula and peripheral retina cluster into four distinct groups. Genes which are highly expressed in macular, peripheral, young or old retina were identified, including inhibitors of Wnt Signaling Pathway (DKK1, FZD10 and SFRP2 which are preferably expressed in the periphery. Conclusions: The transcriptome of the human retina is affected by age and topographic location. Wnt pathway inhibitors in the periphery may maintain peripheral retinal cells in an undifferentiated state. Understanding the effects of age and topographic location on gene expression may lead to the development of new therapeutic interventions for age-related eye diseases.

  13. Caracterización del cemento dental del perro mediante microscopía electrónica de barrido Characterization of dog dental cementum by scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    P.G. Toriggia

    2011-12-01

    Full Text Available El objetivo del trabajo fue caracterizar el cemento dental en el perro utilizando para ello el microscopio electrónico de barrido (MEB. La cara vestibular de 38 raíces dentales fue observada y fotografiada con el MEB, en sus tercios coronario y apical. Se realizó una clasificación morfológica de la superficie y se midió en cada microfotografía el diámetro de 20 fibras de Sharpey, estableciéndose el porcentaje que ocupaban en 600 µm². En el tercio coronario se encontró un cemento de tipo acelular, con fibras de Sharpey densamente agrupadas, proyectándose perpendicularmente a la superficie, ocupando casi su totalidad. El diámetro de las fibras fue de 5.31 ± 0.98 µm. En el tercio apical, se encontró un cemento celular con una densidad de fibras de Sharpey menor al 55%, siendo el resto fibras intrínsecas y lagunas celulares. El diámetro de las fibras fue de 5.47 ± 1.31 µm. Los diámetros de las fibras de Sharpey del tercio apical fueron significativamente mayores (p=0.0000 que aquellos del tercio coronario. Concluimos que la superficie del cemento del perro no es uniforme en toda su extensión, presentando variaciones entre los tercios coronario y apical, así como también dentro del mismo tercio del diente.The aim of this study was to characterize the dental cementum in the dog using the scanning electron microscope (SEM. The buccal surface of 38 dental roots was observed and photographed with the SEM in their coronal and apical thirds. A morphological classification of the surface was performed and also, the diameter of 20 Sharpey fibers was measured in each picture establishing the percentage occupied by them in 600 µm². In the coronal third, acellular cementum was found with the Sharpey fibers closely packed, projecting perpendicular to the surface, occupying almost the whole of it. The diameter of the fibers was of 5.31 ± 0.98 µm. In the apical third, cellular cementum was found, with a density of Sharpey fibers less

  14. Comparación de guantes de látex de uso clínico de diferentes marcas comerciales mediante microscopía electrónica de barrido

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    Gilberto González

    2015-10-01

    Full Text Available Resumen (español El uso de guantes de látex representa la primera barrera contra patógenos por parte del personal de ciencias de la salud, sin embargo, es cotidiano escuchar quejas sobre la calidad de los mismos, ya que en algunos casos tienden a romperse con facilidad disminuyendo así su capacidad protectora, además de utilizar como lubricante almidón de maíz, sustancia que puede provocar alergias. En esta investigación se compararon las características morfológicas del látex y la composición química del polvo de guantes de látex de uso clínico, de cinco marcas comerciales mediante microscopia electrónica de barrido. La calidad protectora se estableció como un arreglo entre el promedio de poros, el diámetro de los mismos y la rugosidad de la superficie. La marca Sensimedical® conto con poros de menor diámetro entre 0,1–0,7 μm, un promedio de 36,7 y superficie poco rugosa, seguida por las marcas Mc medical®, Confit®, King® y por ultimo Medac® con poros entre 0,6-2μm, un promedio de 28,1 y superficie muy rugosa. En cuanto a la composición química elemental del polvo lubricante se encontró predominio de calcio, níquel, magnesio y sodio. La presencia del sodio y magnesio puede deberse a mejorar propiedades de sudoración del usuario, pero el níquel puede generar alergias. Además otros elementos en baja proporción considerados contaminantes. Abstract (english The use of latex gloves is the first barrier against pathogens from the staff of health sciences, however, it is commonplace to hear complaints about the quality of them, since in some cases tend to break easily thus reducing their protective capacity, besides using corn starch as a lubricant, a substance that can cause allergies. In this research the morphological characteristics of latex and chemical composition of the powder latex gloves for clinical use, five trademarks by scanning electron microscopy were compared. The protective quality was established

  15. Agregación de sedimentos en una cuenca de llanura: utilización del Microscopio Electrónico de Barrido como herramienta de evaluación

    Directory of Open Access Journals (Sweden)

    Suarez, P.

    2015-12-01

    sedimentos de fondo del río Negro, tributario del río Paraná, ubicado en la provincia del Chaco (Argentina. Para ello se realizaron análisis granulométricos en etapas consecutivas de procesamiento de muestras que evaluaron los efectos de la presencia de materia orgánica y las sales disueltas en el estado de agregación de las partículas sedimentarias. En cada etapa las muestras fueron observadas bajo Microscopio Electrónico de Barrido (MEB. Los resultados conseguidos representan la primera evaluación cuantitativa sobre la presencia de agregados naturales de sedimentos en un río de la llanura Chaqueña, pudiéndose usar además como referencia para la caracterización de otros ríos similares. Los resultados obtenidos permiten apreciar un aumento marcado de la fracción limo al eliminar materia orgánica, y de la fracción arcilla al eliminar el efecto electroquímico producto de las altas concentraciones salinas. Se concluye que para estudios destinados a interpretaciones ambientales no es recomendable el uso de técnicas que incluyan eliminación de materia orgánica particulada fina y la dispersión química, pues la información generada puede conducir a una interpretación sesgada de la dinámica de transporte de los sedimentos en el medio natural.

  16. Heterogeneity of glia in the retina and optic nerve of birds and mammals.

    Directory of Open Access Journals (Sweden)

    Andy J Fischer

    Full Text Available We have recently described a novel type of glial cell that is scattered across the inner layers of the avian retina [1]. These cells are stimulated by insulin-like growth factor 1 (IGF1 to proliferate, migrate distally into the retina, and up-regulate the nestin-related intermediate filament transition. These changes in glial activity correspond with increased susceptibility of neurons to excitotoxic damage. This novel cell-type has been termed the Non-astrocytic Inner Retinal Glia-like (NIRG cells. The purpose of the study was to investigate whether the retinas of non-avian species contain cells that resemble NIRG cells. We assayed for NIRG cells by probing for the expression of Sox2, Sox9, Nkx2.2, vimentin and nestin. NIRG cells were distinguished from astrocytes by a lack of expression for Glial Fibrilliary Acidic Protein (GFAP. We examined the retinas of adult mice, guinea pigs, dogs and monkeys (Macaca fasicularis. In the mouse retina and optic nerve head, we identified numerous astrocytes that expressed GFAP, S100beta, Sox2 and Sox9; however, we found no evidence for NIRG-like cells that were positive for Nkx2.2, nestin, and negative for GFAP. In the guinea pig retina, we did not find astrocytes or NIRG cells in the retina, whereas we identified astrocytes in the optic nerve. In the eyes of dogs and monkeys, we found astrocytes and NIRG-like cells scattered across inner layers of the retina and within the optic nerve. We conclude that NIRG-like cells are present in the retinas of canines and non-human primates, whereas the retinas of mice and guinea pigs do not contain NIRG cells.

  17. Purinergic control of vascular tone in the retina.

    Science.gov (United States)

    Kur, Joanna; Newman, Eric A

    2014-02-01

    Purinergic control of vascular tone in the CNS has been largely unexplored. This study examines the contribution of endogenous extracellular ATP, acting on vascular smooth muscle cells, in controlling vascular tone in the in vivo rat retina. Retinal vessels were labelled by i.v. injection of a fluorescent dye and imaged with scanning laser confocal microscopy. The diameters of primary arterioles were monitored under control conditions and following intravitreal injection of pharmacological agents. Apyrase (500 units ml(-1)), an ATP hydrolysing enzyme, dilated retinal arterioles by 40.4 ± 2.8%, while AOPCP (12.5 mm), an ecto-5'-nucleotidase inhibitor that increases extracellular ATP levels, constricted arterioles by 58.0 ± 3.8% (P < 0.001 for both), demonstrating the importance of ATP in the control of basal vascular tone. Suramin (500 μm), a broad-spectrum P2 receptor antagonist, dilated retinal arterioles by 50.9 ± 3.7% (P < 0.001). IsoPPADS (300 μm) and TNP-ATP (50 μm), more selective P2X antagonists, dilated arterioles by 41.0 ± 5.3% and 55.2 ± 6.1% respectively (P < 0.001 for both). NF023 (50 μm), a potent antagonist of P2X1 receptors, dilated retinal arterioles by 32.1 ± 2.6% (P < 0.001). A438079 (500 μm) and AZ10606120 (50 μm), P2X7 antagonists, had no effect on basal vascular tone (P = 0.99 and P = 1.00 respectively). In the ex vivo retina, the P2X1 receptor agonist α,β-methylene ATP (300 nm) evoked sustained vasoconstrictions of 18.7 ± 3.2% (P < 0.05). In vivo vitreal injection of the gliotoxin fluorocitrate (150 μm) dilated retinal vessels by 52.3 ± 1.1% (P < 0.001) and inhibited the vasodilatory response to NF023 (50 μm, 7.9 ± 2.0%; P < 0.01). These findings suggest that vascular tone in rat retinal arterioles is maintained by tonic release of ATP from the retina. ATP acts on P2X1 receptors, although contributions from other P2X and P2Y receptors cannot be ruled out. Retinal glial cells are a possible source of the vasoconstricting ATP.

  18. Label-free nonlinear optical imaging of mouse retina.

    Science.gov (United States)

    He, Sicong; Ye, Cong; Sun, Qiqi; Leung, Christopher K S; Qu, Jianan Y

    2015-03-01

    A nonlinear optical (NLO) microscopy system integrating stimulated Raman scattering (SRS), two-photon excited fluorescence (TPEF) and second-harmonic generation (SHG) was developed to image fresh mouse retinas. The morphological and functional details of various retinal layers were revealed by the endogenous NLO signals. Particularly, high resolution label-free imaging of retinal neurons and nerve fibers in the ganglion cell and nerve fiber layers was achieved by capturing endogenous SRS and TPEF signals. In addition, the spectral and temporal analysis of TPEF images allowed visualization of different fluorescent components in the retinal pigment epithelium (RPE). Fluorophores with short TPEF lifetime, such as A2E, can be differentiated from other long-lifetime components in the RPE. The NLO imaging method would provide important information for investigation of retinal ganglion cell degeneration and holds the potential to study the biochemical processes of visual cycle in the RPE.

  19. Pixel detectors for use in retina neurophysiology studies

    CERN Document Server

    Cunningham, W; Chichilnisky, E J; Horn, M; Litke, A M; Mathieson, K; McEwan, F A; Melone, J; O'Shea, V; Rahman, M; Smith, K M

    2003-01-01

    One area of major inter-disciplinary co-operation is between the particle physics and bio-medical communities. The type of large detector arrays and fast electronics developed in laboratories like CERN are becoming used for a wide range of medical and biological experiments. In the present work fabrication technology developed for producing semiconductor radiation detectors has been applied to produce arrays which have been used in neuro-physiological experiments on retinal tissue. We have exploited UVIII, a low molecular weight resist, that has permitted large area electron beam lithography. This allows the resolution to go below that of conventional photolithography and hence the production of densely packed similar to 500 electrode arrays with feature sizes down to below 2 mum. The neural signals from significant areas of the retina may thus be captured.

  20. Tgfbi/Bigh3 silencing activates ERK in mouse retina.

    Science.gov (United States)

    Allaman-Pillet, Nathalie; Oberson, Anne; Bustamante, Mauro; Tasinato, Andrea; Hummler, Edith; Schorderet, Daniel F

    2015-11-01

    BIGH3 is a secreted protein, part of the extracellular matrix where it interacts with collagen and integrins on the cell surface. BIGH3 can play opposing roles in cancer, acting as either tumor suppressor or promoter, and its mutations lead to different forms of corneal dystrophy. Although many studies have been carried out, little is known about the physiological role of BIGH3. Using the cre-loxP system, we generated a mouse model with disruption of the Bigh3 genomic locus. Bigh3 silencing did not result in any apparent phenotype modifications, the mice remained viable and fertile. We were able to determine the presence of BIGH3 in the retinal pigment epithelium (RPE). In the absence of BIGH3, a transient decrease in the apoptotic process involved in retina maturation was observed, leading to a transient increase in the INL thickness at P15. This phenomenon was accompanied by an increased activity of the pro-survival ERK pathway.

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

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    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.

  2. Visual system based on artificial retina for motion detection.

    Science.gov (United States)

    Barranco, Francisco; Díaz, Javier; Ros, Eduardo; del Pino, Begoña

    2009-06-01

    We present a bioinspired model for detecting spatiotemporal features based on artificial retina response models. Event-driven processing is implemented using four kinds of cells encoding image contrast and temporal information. We have evaluated how the accuracy of motion processing depends on local contrast by using a multiscale and rank-order coding scheme to select the most important cues from retinal inputs. We have also developed some alternatives by integrating temporal feature results and obtained a new improved bioinspired matching algorithm with high stability, low error and low cost. Finally, we define a dynamic and versatile multimodal attention operator with which the system is driven to focus on different target features such as motion, colors, and textures.

  3. Differential changes in retina function with normal aging in humans.

    Science.gov (United States)

    Freund, Paul R; Watson, Juliane; Gilmour, Gregory S; Gaillard, Frédéric; Sauvé, Yves

    2011-06-01

    We evaluated the full field electroretinogram (ERG) to assess age-related changes in retina function in humans. ERG recordings were performed on healthy subjects with normal fundus appearance, lack of cataract and 20/20 acuity, aged 20-39 years (n = 27; mean age 25 ± 5, standard deviation), 40-59 years (n = 20; mean 53 ± 5), and 60-82 years (n = 18; mean 69 ± 5). Multiple ERG tests were applied, including light and dark-adapted stimulus-response function, dark adaptation and dynamic of recovery from a single bright flash under dark-adapted conditions. Changes in ERG properties were found in the oldest age group when compared with the two younger age groups. (1) The photopic hill effect was less pronounced. (2) Both photopic a-wave and b-wave amplitudes and implicit times were increased at high stimulus strengths. (3) Dark adaptation time was delayed for pure rod and L/M cone-driven responses, respectively. (4) Dark-adapted a-wave but not b-wave amplitudes were reduced, yielding higher B/A ratios. (5) Dark-adapted a- and b-waves implicit times were prolonged: there was a direct proportional correlation between minimal a-wave implicit times and age. (6) The dynamic of dark current recovery from a bright flash, under dark-adapted conditions, was transiently faster at intervals between 0.9 and 2 s. These results denote that aging of the healthy retina is accompanied by specific functional changes, which must be taken into account to optimally diagnose potential pathologies.

  4. Axonal synapses utilize multiple synaptic ribbons in the mammalian retina.

    Directory of Open Access Journals (Sweden)

    Hong-Lim Kim

    Full Text Available In the mammalian retina, bipolar cells and ganglion cells which stratify in sublamina a of the inner plexiform layer (IPL show OFF responses to light stimuli while those that stratify in sublamina b show ON responses. This functional relationship between anatomy and physiology is a key principle of retinal organization. However, there are at least three types of retinal neurons, including intrinsically photosensitive retinal ganglion cells (ipRGCs and dopaminergic amacrine cells, which violate this principle. These cell types have light-driven ON responses, but their dendrites mainly stratify in sublamina a of the IPL, the OFF sublayer. Recent anatomical studies suggested that certain ON cone bipolar cells make axonal or ectopic synapses as they descend through sublamina a, thus providing ON input to cells which stratify in the OFF sublayer. Using immunoelectron microscopy with 3-dimensional reconstruction, we have identified axonal synapses of ON cone bipolar cells in the rabbit retina. Ten calbindin ON cone bipolar axons made en passant ribbon synapses onto amacrine or ganglion dendrites in sublamina a of the IPL. Compared to the ribbon synapses made by bipolar terminals, these axonal ribbon synapses were characterized by a broad postsynaptic element that appeared as a monad and by the presence of multiple short synaptic ribbons. These findings confirm that certain ON cone bipolar cells can provide ON input to amacrine and ganglion cells whose dendrites stratify in the OFF sublayer via axonal synapses. The monadic synapse with multiple ribbons may be a diagnostic feature of the ON cone bipolar axonal synapse in sublamina a. The presence of multiple ribbons and a broad postsynaptic density suggest these structures may be very efficient synapses. We also identified axonal inputs to ipRGCs with the architecture described above.

  5. Membrane currents of spiking cells isolated from turtle retina.

    Science.gov (United States)

    Lasater, E M; Witkovsky, P

    1990-05-01

    We examined the membrane properties of spiking neurons isolated from the turtle (Pseudemys scripta) retina. The cells were maintained in culture for 1-7 days and were studied with the whole cell patch clamp technique. We utilized cells whose perikaryal diameters were greater than 15 microns since Kolb (1982) reported that ganglion cell perikarya in Pseudemys retina are 13-25 microns, whereas amacrine perikarya are less than 14 microns in diameter. We identified 5 currents in the studied cells: (1) a transient sodium current (INa) blocked by TTX, (2) a sustained calcium current (ICa) blocked by cobalt and enhanced by Bay-K 8644, (3) a calcium-dependent potassium current (IK(Ca)), (4) an A-type transient potassium current (IA) somewhat more sensitive to 4-AP than TEA, (5) a sustained potassium current (IK) more sensitive to TEA than 4-AP. The estimated average input resistance of the cells at -70 mV was 720 +/- 440 M omega. When all active currents were blocked, the membrane resistance between -130 and +20 mV was 2.5 G omega. When examined under current clamp, some cells produced multiple spikes to depolarizing steps of 0.1-0.3 nA, whereas other cells produced only a single spike irrespective of the strength of the current pulse. Most single spikers had an outward current that rose to a peak relatively slowly, whereas multiple spikers tend to have a more rapidly activating outward current. Under current clamp, 4-AP slowed the repolarization phase of the spike thus broadening it, but did not always abolish the ability to produce multiple spikes. TEA induced a depolarized plateau following the initial spike which precluded further spikes. It thus appears that the spiking patterns of the retinal cells are shaped primarily by the kinetics of INa, IK and IA and to a lesser extent by IK(Ca).

  6. Novel features of neurodegeneration in the inner retina of early diabetic rats.

    Science.gov (United States)

    Énzsöly, Anna; Szabó, Arnold; Szabó, Klaudia; Szél, Ágoston; Németh, János; Lukáts, Ákos

    2015-08-01

    The literature indicates that in diabetes retinal dysfunctions related to neural retinal alterations exist prior to clinically detectable vasculopathy. In a previous report, a detailed description about the alteration of the outer retina was given, where diabetic degeneration preceded apoptotic loss of cells (Enzsöly et al., 2014). Here, we investigated the histopathology of the inner retina in early diabetes using the same specimens. We examined rat retinas with immunohistochemistry and Western blotting, 12 weeks after streptozotocin induction of diabetes. Glial reactivity was observed in all diabetic retinal specimens; however, it was not detectable all over the retina, but appeared in randomly arranged patches, with little or no glia activation in between. Similarly, immunoreactivity of parvalbumin (staining mostly AII amacrine cells) was also decreased only in some regions. We propose that these focal changes appear prior to affecting the whole retina and overt loss of cells. In contrast to these, most other markers used (calretinin, recoverin, tyrosin hydroxylase anti-Brn-3a and also calbindin in the optic part of the retina) did not show any major alterations in the intensity of immunoreactivity or in the number of stained elements. Interestingly, under diabetic conditions, the labeling pattern of PKC-α and calbindin in the ciliary retina showed a clear resemblance to the pattern described during development. This observation is in line with our previous study, reporting an increase in the number of dual cones, coexpressing two photopigments, which is another common feature with developing retinas. These data may indicate a previously uninvestigated regenerative capacity in diabetic retina.

  7. The role of histamine in the retina: studies on the Hdc knockout mouse.

    Science.gov (United States)

    Greferath, Ursula; Vessey, Kirstan A; Jobling, Andrew I; Mills, Samuel A; Bui, Bang V; He, Zheng; Nag, Nupur; Ohtsu, Hiroshi; Fletcher, Erica L

    2014-01-01

    The role of histamine in the retina is not well understood, despite it regulating a number of functions within the brain, including sleep, feeding, energy balance, and anxiety. In this study we characterized the structure and function of the retina in mice that lacked expression of the rate limiting enzyme in the formation of histamine, histidine decarboxylase (Hdc-/- mouse). Using laser capture microdissection, Hdc mRNA expression was assessed in the inner and outer nuclear layers of adult C57Bl6J wildtype (WT) and Hdc(-/-)-retinae. In adult WT and Hdc(-/-)-mice, retinal fundi were imaged, retinal structure was assessed using immunocytochemistry and function was probed by electroretinography. Blood flow velocity was assessed by quantifying temporal changes in the dynamic fluorescein angiography in arterioles and venules. In WT retinae, Hdc gene expression was detected in the outer nuclear layer, but not the inner nuclear layer, while the lack of Hdc expression was confirmed in the Hdc-/- retina. Preliminary examination of the fundus and retinal structure of the widely used Hdc-/- mouse strain revealed discrete lesions across the retina that corresponded to areas of photoreceptor abnormality reminiscent of the rd8 (Crb1) mutation. This was confirmed after genotyping and the strain designated Hdcrd8/rd8. In order to determine the effect of the lack of Hdc-alone on the retina, Hdc-/- mice free of the Crb1 mutation were bred. Retinal fundi appeared normal in these animals and there was no difference in retinal structure, macrogliosis, nor any change in microglial characteristics in Hdc-/- compared to wildtype retinae. In addition, retinal function and retinal blood flow dynamics showed no alterations in the Hdc-/- retina. Overall, these results suggest that histamine plays little role in modulating retinal structure and function.

  8. 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.

  9. Increased frequency of anti-retina antibodies in asymptomatic patients with chronic t. gondii infection

    Science.gov (United States)

    Cursino, Sylvia Regina Temer; da Costa, Thaís Boccia; Yamamoto, Joyce Hisae; Meireles, Luciana Regina; Silva, Maria Antonieta Longo Galvão; de Andrade Junior, Heitor Franco

    2010-01-01

    PURPOSE: To search for anti-retina antibodies that serve as markers for eye disease in uveitis. MATERIALS AND METHODS: Stored sera from patients with uveitis, ocular toxoplasmosis (n = 30) and non-infectious, immune-mediated uveitis (n = 50) and from asymptomatic individuals who were positive (n = 250) and negative (n = 250) for anti-Toxoplasma antibodies were tested. Serum anti-retina IgG was detected by an optimized ELISA using a solid-phase whole human retina extract, bovine S-antigen or interphotoreceptor retinoid-binding protein. RESULTS: Uveitis patients showed a higher mean reactivity to whole human retina extract, interphotoreceptor retinoid-binding protein and S-antigen in comparison to the asymptomatic population. These findings were independent of the uveitis origin and allowed the determination of the lower anti-retina antibody cut-off for the three antigens. Asymptomatic anti-Toxoplasma serum-positive individuals showed a higher frequency of anti-human whole retina extract antibodies in comparison to asymptomatic anti-Toxoplasma serum-negative patients. The bovine S-antigen and interphotoreceptor retinoid-binding protein ELISAs also showed a higher mean reactivity in the uveitis groups compared to the asymptomatic group, but the observed reactivities were lower and overlapped without discrimination. CONCLUSION: We detected higher levels of anti-retina antibodies in uveitis patients and in a small fraction of asymptomatic patients with chronic toxoplasmosis. The presence of anti-retina antibodies in sera might be a marker of eye disease in asymptomatic patients, especially when whole human retina extract is used in a solid-phase ELISA. PMID:21120306

  10. Increased frequency of anti-retina antibodies in asymptomatic patients with chronic t. gondii infection

    Directory of Open Access Journals (Sweden)

    Sylvia Regina Temer Cursino

    2010-01-01

    Full Text Available PURPOSE: To search for anti-retina antibodies that serve as markers for eye disease in uveitis. MATERIALS AND METHODS: Stored sera from patients with uveitis, ocular toxoplasmosis (n = 30 and non-infectious, immune-mediated uveitis (n = 50 and from asymptomatic individuals who were positive (n = 250 and negative (n = 250 for anti-Toxoplasma antibodies were tested. Serum anti-retina IgG was detected by an optimized ELISA using a solid-phase whole human retina extract, bovine S-antigen or interphotoreceptor retinoid-binding protein. RESULTS: Uveitis patients showed a higher mean reactivity to whole human retina extract, interphotoreceptor retinoid-binding protein and S-antigen in comparison to the asymptomatic population. These findings were independent of the uveitis origin and allowed the determination of the lower anti-retina antibody cut-off for the three antigens. Asymptomatic anti-Toxoplasma serum-positive individuals showed a higher frequency of antihuman whole retina extract antibodies in comparison to asymptomatic anti-Toxoplasma serum-negative patients. The bovine S-antigen and interphotoreceptor retinoid-binding protein ELISAs also showed a higher mean reactivity in the uveitis groups compared to the asymptomatic group, but the observed reactivities were lower and overlapped without discrimination. CONCLUSION: We detected higher levels of anti-retina antibodies in uveitis patients and in a small fraction of asymptomatic patients with chronic toxoplasmosis. The presence of anti-retina antibodies in sera might be a marker of eye disease in asymptomatic patients, especially when whole human retina extract is used in a solid-phase ELISA.

  11. Descripción de la morfología externa por microscopia de luz y electrónica de barrido de Megninia ginglymura, Megnin, 1877 en faisán de collar (Phasianus torquatus, en un criadero de Corrientes, Argentina

    Directory of Open Access Journals (Sweden)

    A. Santa Cruz ; M. C. Agüero ; J. A. González; J.A Comolli ; D. Cayo; J. P. Roux.-

    2008-09-01

    Full Text Available El objetivo de este trabajo es reportar el primer hallazgo de Megninia ginglymura, Megnin, 1877 (Arthropoda, Arachnida, Acari, Astigmata, Analgidae, en faisán de collar (Phasianus torquatus y describir algunos caracteres morfológicos externos a través imágenes obtenidas con microscopios de luz y microscopio electrónico de barrido. La investigación se llevó a cabo en un criadero ubicado en la localidad del Ingenio Santa Ana de la ciudad de Corrientes, Latitud 27º 26´ 01, Longitud 58º 37´ 21. Del plantel de 500 faisanes de collar (Phasianus torquatus se examinaron 15 (10 animales jóvenes y 5 adultos que presentaban lesiones principalmente en la cabeza, cuello y dorso, y se tomaron muestras de plumas de las zonas afectadas. Se colectaron ácaros que fueron montados entre porta y cubreobjetos con líquido de Hoyer’s, para su posterior clasificación sistemática; los ejemplares destinados a microscopía electrónica de barrido se conservaron en Glutaraldehído al 3%. Los especimenes presentaron pronunciado dimorfismo sexual, en el macho se observó el tercer par de patas más desarrollada y la presencia de lóbulos posteriores con ventosas copulatrices. En las hembras se advirtió lasimilitud de todas las patas, con el borde posterior de su cuerposemiredondeado. Las lesiones observadas fueron pérdida y corte deplumas en las alas, dorso y en la mayor parte del cuerpo. Estas lesiones corresponden a la acción parasitaria de Megninia ginglymura. Constituye el primer hallazgo en faisán de collar (Phasianus torquatus y la primera descripción de algunos aspectos morfológicos externos de Megninia ginglymura, Megnin, 1877 (Arthropoda, Arachnida, Acari, Astigmata, Analgidae, que se realiza mediante el uso de microscopio de luz y microscopio electrónico de barrido en la Argentina.

  12. La Biblioteca de la Universidad de Heidelberg y su colección temática especializada de Historia del Arte

    Directory of Open Access Journals (Sweden)

    Effinger, Maria

    2001-07-01

    Full Text Available La Biblioteca de la Universidad de Heidelberg participa en el sistema nacional cooperativo de adquisición de libros financiado por la Asociación Alemana de Investigación (Deutsche Forschungsgemeinschaft, en adelante DFG. Esta institución financia la construcción de fondos bibliográficos académicos con el doble fin de tejer una red de fuentes de información y hacer que éstas sean accesibles desde cualquier punto de la nación. Más de sesenta de las más eficientes bibliotecas universitarias alemanas participan en este sistema de cooperación. Las colecciones especializadas sed distribuyen de acuerdo con criterios académicos y regionales. La finalidad de este sistema de adquisición cooperativa es construir colecciones temáticas especializadas y comprensivas de recursos impresos y electrónicos y hacerlas accesibles de un modo fácil, pensando en el usuario. La DFG financia la adquisición de la producción completa de las obras más relevantes que se publican en el extranjero, mientras que a las bibliotecas les corresponde el pago de la literatura extranjera más común y de los documentos publicados en Alemania.

  13. ‘... conceived by the Holy Spirit and born of the Virgin Mary’: The exposition of the Heidelberg Catechism in the light of present-day criticism

    Directory of Open Access Journals (Sweden)

    Ignatius W.C. (Natie van Wyk

    2014-02-01

    Full Text Available The article is a contribution to the 450 year celebrations of the Heidelberg Catechism (HC. Sunday 14, Questions and Answers 35 and 36 receive attention. It deals with the two statements of the creed ‘… conceived by the Holy Spirit and born of the Virgin Mary’. The exposition of the HC is compared to the catechisms of Zacharias Ursinus and John Calvin in order to capture something about the historicity of the text. The exposition of the creed is an on-going process. Karl Barth, Eberhard Busch and Jan Milič Lochman are good examples of Reformed theologians who remain faithful to the intention of the HC, but who explain these statements with present-day criticism in mind. The exposition of Peter Berger is valuable because this sceptic argues that the opinion of modern, liberal Protestantism is of no value. The article concludes that the ‘virgin birth’ as such has no great value. It is only one aspect of the Christian gospel. It also does not proof the divinity of Christ. The divinity of Christ is presupposed.

  14. Simulation and performance of an artificial retina for 40 MHz track reconstruction

    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

    2015-01-01

    We present the results of a detailed simulation of the artificial retina pattern-recognition algorithm, designed to reconstruct events with hundreds of charged-particle tracks in pixel and silicon detectors at LHCb with LHC crossing frequency of 40MHz. The detailed geometry and charged-particle activity of a large tracking detector are simulated and used to assess the performance of the artificial retina algorithm. Excellent performances have been found for the retina pattern-recognition algorithm, comparable with the full LHCb reconstruction algorithm.

  15. Dual-path handheld system for cornea and retina imaging using optical coherence tomography

    Science.gov (United States)

    Shirazi, Muhammad Faizan; Wijesinghe, Ruchire Eranga; Ravichandran, Naresh Kumar; Kim, Pilun; Jeon, Mansik; Kim, Jeehyun

    2016-11-01

    A dual-path handheld system is proposed for cornea and retina imaging using spectral domain optical coherence tomography. The handheld sample arm is designed to acquire two images simultaneously. Both eyes of a person can be imaged at the same time to obtain the images of the cornea of one eye and the retina of the other eye. Cornea, retina, and optic disc images are acquired with the proposed sample arm. Experimental results demonstrate the usefulness of this system for imaging of different eye segments. This system reduces the time required for imaging of the two eyes and is cost effective.

  16. Semiconductor nanorod-carbon nanotube biomimetic films for wire-free photostimulation of blind retinas.

    Science.gov (United States)

    Bareket, Lilach; Waiskopf, Nir; Rand, David; Lubin, Gur; David-Pur, Moshe; Ben-Dov, Jacob; Roy, Soumyendu; Eleftheriou, Cyril; Sernagor, Evelyne; Cheshnovsky, Ori; Banin, Uri; Hanein, Yael

    2014-11-12

    We report the development of a semiconductor nanorod-carbon nanotube based platform for wire-free, light induced retina stimulation. A plasma polymerized acrylic acid midlayer was used to achieve covalent conjugation of semiconductor nanorods directly onto neuro-adhesive, three-dimensional carbon nanotube surfaces. Photocurrent, photovoltage, and fluorescence lifetime measurements validate efficient charge transfer between the nanorods and the carbon nanotube films. Successful stimulation of a light-insensitive chick retina suggests the potential use of this novel platform in future artificial retina applications.

  17. Structural and molecular analysis of arteriolar annuli in the retina: implications in diabetic and hypertensive retinopathy

    OpenAIRE

    Ramos Gonzalez, David

    2014-01-01

    La vasculatura de la retina presenta características especiales ya que es fundamental que los vasos no interfieran el paso de la luz, que debe atravesar la retina para llegar a los fotoreceptores. El pequeño calibre de los capilares retinianos, junto con los elevados requerimientos metabólicos, hace que la regulación del flujo sanguíneo sea fundamental para el correcto mantenimiento de la homeostasis de la retina. La vasculatura retiniana no presenta inervación, por lo que la influencia de es...

  18. Stem/progenitor cells: a potential source of retina-specific cells for retinal repair.

    Science.gov (United States)

    Bi, Yong-Yan; Feng, Dong-Fu; Pan, Dong-Chao

    2009-11-01

    Retinal injury generally results in permanent visual disturbance or even blindness. Any effort to restore vision in such condition would require replacement of the highly specialized retinal cells. Stem/progenitor cells have been proposed as a potential source of new retina-specific cells to replace those lost due to retina injury. Evidence to date suggests that continued development of stem cell therapies may ultimately lead to viable treatment options for retina injury. A wide range of stem/progenitor cells from various sources is currently being investigated for the treatment of retinal injury. This article reviews the recent achievements about stem/progenitor cell source for retinal repair.

  19. Differential Gene Expression in Retina of Myopic Chicken Eyes Using mRNA Differential Display

    Institute of Scientific and Technical Information of China (English)

    ShenHX; ZhangQJ

    1999-01-01

    Purpose:To study differentially expressed genes in retina of experimental myopic chicken.Methods:Experimental myopia in chicken was induced by form-deprivatin.The mRNA in chicen retina was analyzed by using differential display.Results:Experimental myopia was successfully induced in chicken through form-deprivation.Differentially expressed gene fragments were detected in retina of chicken with myopic evelopment and recovery as compared with normal controld.Conclusion:The differential display of mRNA may be a useful way in cloning myopic-related genes.

  20. Human retina-specific amine oxidase: genomic structure of the gene (AOC2), alternatively spliced variant, and mRNA expression in retina.

    Science.gov (United States)

    Imamura, Y; Noda, S; Mashima, Y; Kudoh, J; Oguchi, Y; Shimizu, N

    1998-07-15

    Previously, we reported the isolation of cDNA for human retina-specific amine oxidase (RAO) and the expression of RAO exclusively in retina. Bacterial artificial chromosome clones containing the human RAO gene (AOC2) were mapped to human chromosome 17q21 (Imamura et al., 1997, Genomics 40: 277-283). Here, we report the complete genomic structure of the RAO gene, including 5' flanking sequence, and mRNA expression in retina. The human RAO gene spans 6 kb and is composed of four exons corresponding to the amino acid sequence 1-530, 530-598, 598-641, and 642-729 separated by three introns of 3000, 310, and 351 bp. Screening of a human retina cDNA library revealed the existence of an alternatively spliced cDNA variant with an additional 81 bp at the end of exon 2. The sizes of exons and the locations of exon/intron boundaries in the human RAO gene showed remarkable similarity to those of the human kidney diamine oxidase gene (AOC1). In situ hybridization revealed that mRNA coding for RAO is expressed preferentially in the ganglion cell layer of the mouse retina. We designed four sets of PCR primers to amplify four exons, which will be valuable for analyzing mutations in patients with ocular diseases affecting the retinal ganglion cell layer.

  1. Organotypic tissue culture of adult rodent retina followed by particle-mediated acute gene transfer in vitro.

    Directory of Open Access Journals (Sweden)

    Satoru Moritoh

    Full Text Available BACKGROUND: Organotypic tissue culture of adult rodent retina with an acute gene transfer that enables the efficient introduction of variable transgenes would greatly facilitate studies into retinas of adult rodents as animal models. However, it has been a difficult challenge to culture adult rodent retina. The purpose of this present study was to develop organotypic tissue culture of adult rodent retina followed by particle-mediated acute gene transfer in vitro. METHODOLOGY/PRINCIPAL FINDINGS: We established an interphase organotypic tissue culture for adult rat retinas (>P35 of age which was optimized from that used for adult rabbit retinas. We implemented three optimizations: a greater volume of Ames' medium (>26 mL per retina, a higher speed (constant 55 rpm of agitation by rotary shaker, and a greater concentration (10% of horse serum in the medium. We also successfully applied this method to adult mouse retina (>P35 of age. The organotypic tissue culture allowed us to keep adult rodent retina morphologically and structurally intact for at least 4 days. However, mouse retinas showed less viability after 4-day culture. Electrophysiologically, ganglion cells in cultured rat retina were able to generate action potentials, but exhibited less reliable light responses. After transfection of EGFP plasmids by particle-mediated acute gene transfer, we observed EGFP-expressing retinal ganglion cells as early as 1 day of culture. We also introduced polarized-targeting fusion proteins such as PSD95-GFP and melanopsin-EYFP (hOPN4-EYFP into rat retinal ganglion cells. These fusion proteins were successfully transferred into appropriate locations on individual retinal neurons. CONCLUSIONS/SIGNIFICANCE: This organotypic culture method is largely applicable to rat retinas, but it can be also applied to mouse retinas with a caveat regarding cell viability. This method is quite flexible for use in acute gene transfection in adult rodent retina, replacing

  2. Polyphonie als mehrfach eingebettete Rede bei Flaubert. Andrea Landvogts Verbindung linguistischer und narratologischer Ansätze zu einer Typologie der Redewiedergabe [Andrea Landvogt: Discours cités. Eine äußerungs- und erzähltheoretisch fundierte Typologie der Redewiedergabe am Beispiel von Gustave Flaubert. Heidelberg 2011

    Directory of Open Access Journals (Sweden)

    Frauke Bode

    2013-06-01

    Full Text Available Rezension zu / Review of:Andrea Landvogt: Discours cités. Eine äußerungs- und erzähltheoretisch fundierte Typologie der Redewiedergabe am Beispiel von Gustave Flaubert. Heidelberg 2011. 

  3. Comparison of dark- and light-adapted carp retinas with NADPH diaphorase staining

    Institute of Scientific and Technical Information of China (English)

    叶冰; 杨雄里

    1996-01-01

    The carp retina was examined by NADPH diaphorase histochemistry to determine if the staining pattern of retinal cells was changed depending on the adaptation state of the retina. When dark-adapted for 5 h, ellipsoids of inner segments of both rods and cones and some horizontal cells were heavily stained. Staining was also found in subpopulations of amacrine cells and ganglion cells. In addition, Muller cells were strongly positive for NADPH diaphorase. When light-adapted for 5h, ellipsoids of photoreceptors and ganglion cells were less intensely stained, whereas Muller cells and horizontal cells became negative for NADPH diaphorase. Furthermore, rod ON-center bipolar cells were clearly stained. The difference of staining of amacrine cells between dark- and light-adapted retinas was not significant. The differences in diaphorase-staining pattern between dark- and light-adapted retinas suggest that Muller cells, some horizontal cells and rod ON-center bipolar cells contain inducible nitric oxide synthase,

  4. Retina-on-a-chip: a microfluidic platform for point access signaling studies.

    Science.gov (United States)

    Dodson, Kirsten H; Echevarria, Franklin D; Li, Deyu; Sappington, Rebecca M; Edd, Jon F

    2015-12-01

    We report on a microfluidic platform for culture of whole organs or tissue slices with the capability of point access reagent delivery to probe the transport of signaling events. Whole mice retina were maintained for multiple days with negative pressure applied to tightly but gently bind the bottom of the retina to a thin poly-(dimethylsiloxane) membrane, through which twelve 100 μm diameter through-holes served as fluidic access points. Staining with toluidine blue, transport of locally applied cholera toxin beta, and transient response to lipopolysaccharide in the retina demonstrated the capability of the microfluidic platform. The point access fluidic delivery capability could enable new assays in the study of various kinds of excised tissues, including retina.

  5. 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.

  6. Adjunctive MSCs enhance myelin formation by xenogenic oligodendrocyte precursors transplanted in the retina

    Institute of Scientific and Technical Information of China (English)

    Aileen Arriola; Mary E Kie; Yufang Shi; Randall D McKinnon

    2010-01-01

    Dear Editor, We examined myelin formation by oligodendrocytes co-transplanted with immunosuppressive mesenchymal stem cells (MSCs). Oligodendrocyte precursor cells (OPCs) were grafted into the mouse retina, and graft survival and maturation was determined with or without adjunctive MSCs.

  7. 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

    Full Text Available The nucleoside adenosine plays an important role as a neurotransmitter or neuromodulator in the central nervous system, including the retina. In the present paper we review compelling evidence showing that adenosine is a signaling molecule in the developing retina. In the chick retina, adenosine transporters are present since early stages of development before the appearance of adenosine A1 receptors modulating dopamine-dependent adenylate cyclase activity or A2 receptors that directly activate the enzyme. Experiments using retinal cell cultures revealed that adenosine is taken up by specific cell populations that when stimulated by depolarization or neurotransmitters such as dopamine or glutamate, release the nucleoside through calcium-dependent transporter-mediated mechanisms. The presence of adenosine in the extracellular medium and the long-term activation of adenosine receptors is able to regulate the survival of retinal neurons and blocks glutamate excitoxicity. Thus, adenosine besides working as a neurotransmitter or neuromodulator in the mature retina, is considered as an important signaling molecule during retinal development having important functions such as regulation of neuronal survival and differentiation.O nucleosídeo adenosina apresenta um importante papel como neurotransmissor ou neuromodulador no sistema nervoso central, inclusive na retina. Neste artigo apresentamos uma revisão das evidências que mostram que a adenosina é uma molécula sinalizadora na retina em desenvolvimento. Na retina de pinto, transportadores de adenosina estão presentes desde estágios precoces do desenvolvimento, antes do aparecimento dos receptores A1 que modulam a atividade adenilato ciclase dependente de dopamina ou dos receptores A2 que ativam diretamente a enzima. Experimentos usando culturas de células de retina revelaram que a adenosina é captada por populações celulares específicas que, quando estimuladas por despolarização ou por

  8. A Study of Histology and Enzymatic Histochemistry on Rabbit's Retina in Acute Ocular Hypertension

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    The changes of activities of enzymes relating to energy metabolism in rabbit's retina in acute ocular hypertension were observed. The activities of succinate dehydrogenase and adenosine triphosphatase were found to be reduced, while the activities of the lactatic dehydrognease and glucose-6-phosphatase increased. The results revealed the metabolic disturbance of energy in retina after acute ocular hypertension might be the underlying factors relating to the defects of the functions and structures of the...

  9. Rax: Developmental and Daily Expression Patterns in the Rat Pineal Gland and Retina

    OpenAIRE

    Rohde, Kristian; Klein, David C.; Møller, Morten; Rath, Martin F.

    2011-01-01

    Retina and anterior neural fold homeobox (Rax) gene encodes a transcription factor essential for vertebrate eye development. Recent microarray studies indicate that Rax is expressed in the adult rat pineal gland and retina. The present study reveals that Rax expression levels in the rat change significantly during retinal development with a peak occurring at embryonic day (E) 18, whereas Rax expression in the pineal is relatively delayed and not detectable until E20. In both tissues, Rax is e...

  10. Vascular and avascular retinae in mammals. A funduscopic and fluorescein angiographic study.

    Science.gov (United States)

    Buttery, R G; Haight, J R; Bell, K

    1990-01-01

    Intraretinal blood vessels are present in some and absent in other vertebrate species, including the mammals. Among the marsupials, both vascular and avascular retinae are seen. We determined the funduscopic appearance of the eye, investigated the functional aspects of ocular blood flow in both types of retina in marsupials and compared our results with known patterns in placental mammals. The Australian polyprotodont marsupials, the Tasmanian devil, Sarcophilus harrisii, and the quoll, Dasyurus viverrinus, together with an American polyprotodont, the Virginia opossum, Didelphis virginiana, demonstrate variable degrees of tapetal differentiation, pigmentation and a very close parallel course of their intraretinal arteries and veins over considerable distances. Using the technique of fluorescein angiography, we found that retinal blood flow in the 3 vascular Australian species commenced with arterial filling. Early venous was seen next, followed by the capillary blush. This unusual sequence of vascular flow differs from that of the arterial-capillary-venous filling seen in placental mammals. This difference is most likely a consequence of the known looped, end artery organisation found within marsupial nervous systems, of which the retinae are a part. The 2 diprotodont marsupials examined, the brushtail possum, Trichosurus vulpecula, and the sugar glider, Petaurus breviceps, possess avascular retinae. Only a small residual tuft of fluorescein-impermeable vessels projects from the optic disc into the vitreous. Interestingly, the structural complexity of the central visual system in diprotodonts all of whom possess avascular retinae) is commonly accepted as being greater than that of the stem polyprotodont line (which possess vascular retinae). If retinal function matches this internal complexity, then retinal avascularity may, as in birds, be associated with superior vision. However, as the retinae of these mammals clearly lack any nutritive mechanisms directly

  11. Rhodopsin-like immunoreactivity in the 'all cone' retina of the chameleon (Chameleo chameleo).

    Science.gov (United States)

    Bennis, Mohamed; Molday, Robert S; Versaux-Botteri, Claudine; Repérant, Jacques; Jeanny, Jean-Claude; McDevitt, David S

    2005-05-01

    Chameleons (Order, Reptilia: Family, Lacertilia) are unique among vertebrates in being able to make independent eye movements. The organisation of their retina, however, closely ressembles that of other diurnal lizards; based on morphological studies, it is typically described as containing only cone photoreceptors. We show here that a subpopulation of the photoreceptors are immunolabelled by an antibody directed against rhodopsin, suggesting the presence of rods. We conclude that in the nonmammalian retina, rods and cones cannot be exclusively distinguished on purely morphological grounds.

  12. The lens controls cell survival in the retina: evidence from the blind cavefish Astyanax

    OpenAIRE

    2007-01-01

    The lens influences retinal growth and differentiation during vertebrate eye development but the mechanisms are not understood. The role of the lens in retinal growth and development was studied in the teleost Astyanax mexicanus, which has eyed surface-dwelling (surface fish) and blind cave-dwelling (cavefish) forms. A lens and laminated retina initially develop in cavefish embryos, but the lens dies by apoptosis. The cavefish retina is subsequently disorganized, apoptotic cells appear, the p...

  13. Streaming an image through the eye: The retina seen as a dithered scalable image coder

    CERN Document Server

    Masmoudi, Khaled; Kornprobst, Pierre

    2012-01-01

    We propose the design of an original scalable image coder/decoder that is inspired from the mammalians retina. Our coder accounts for the time-dependent and also nondeterministic behavior of the actual retina. The present work brings two main contributions: As a first step, (i) we design a deterministic image coder mimicking most of the retinal processing stages and then (ii) we introduce a retinal noise in the coding process, that we model here as a dither signal, to gain interesting perceptual features. Regarding our first contribution, our main source of inspiration will be the biologically plausible model of the retina called Virtual Retina. The main novelty of this coder is to show that the time-dependent behavior of the retina cells could ensure, in an implicit way, scalability and bit allocation. Regarding our second contribution, we reconsider the inner layers of the retina. We emit a possible interpretation for the non-determinism observed by neurophysiologists in their output. For this sake, we mode...

  14. Spatiotemporal features of early neuronogenesis differ in wild-type and albino mouse retina

    Science.gov (United States)

    Rachel, Rivka A.; Dolen, Gul; Hayes, Nancy L.; Lu, Alice; Erskine, Lynda; Nowakowski, Richard S.; Mason, Carol A.

    2002-01-01

    In albino mammals, lack of pigment in the retinal pigment epithelium is associated with retinal defects, including poor visual acuity from a photoreceptor deficit in the central retina and poor depth perception from a decrease in ipsilaterally projecting retinal fibers. Possible contributors to these abnormalities are reported delays in neuronogenesis (Ilia and Jeffery, 1996) and retinal maturation (Webster and Rowe, 1991). To further determine possible perturbations in neuronogenesis and/or differentiation, we used cell-specific markers and refined birth dating methods to examine these events during retinal ganglion cell (RGC) genesis in albino and pigmented mice from embryonic day 11 (E11) to E18. Our data indicate that relative to pigmented mice, more ganglion cells are born in the early stages of neuronogenesis in the albino retina, although the initiation of RGC genesis in the albino is unchanged. The cellular organization of the albino retina is perturbed as early as E12. In addition, cell cycle kinetics and output along the nasotemporal axis differ in retinas of albino and pigmented mice, both absolutely, with the temporal aspect of the retina expanded in albino, and relative to the position of the optic nerve head. Finally, blocking melanin synthesis in pigmented eyecups in culture leads to an increase in RGC differentiation, consistent with a role for melanin formation in regulating RGC neuronogenesis. These results point to spatiotemporal defects in neuronal production in the albino retina, which could perturb expression of genes that specify cell fate, number, and/or projection phenotype.

  15. Hazardous effects of fried potato chips on the development of retina in albino rats

    Institute of Scientific and Technical Information of China (English)

    Hassan I El-Sayyad; Saber A Sakr; Gamal M Badawy; Hanaa S Afify

    2011-01-01

    Objective: To evaluate the hazardous effects of fried potato chips upon the retina of two developmental stages of the albino rats aged 7 and 14 days from parturition. Methods: Pregnant rats were arranged into two groups: control pregnant rats and consequently their delivered newborns until reaching 7 and 14 days old from parturition and fried potato chips group in which pregnant rats at the 6th day of gestation maintained on diet formed of fried potato chips supplied from the market mixed with standard diet at a concentration of 50% per each till 7 and 14 post-partum. Three fold integrated approaches were adopted, namely, histological, ultrastructural and proteomic analysis. Results: Histological examination of the retina of the experimental offsprings revealed many histopathological changes, including massive degeneration, vacuolization and cell loss in the ganglion cell layer, as well as general reduction in retinal size. At the ultrastructural level, the retina of experimental offsprings exhibited number of deformities, including ill differentiated and degenerated nuclear layer, malformed and vacuolated pigment epithelium with vesiculated and fragmented rough endoplasmic reticulum, degenerated outer segment of photoreceptors, as well as swollen choriocapillaris and loss of neuronal cells. Proteomic analysis of retina of the two experimental developmental stages showed variations in the expressed proteins as a result of intoxication which illustrated the adverse toxic effects of fried potato chips upon the retina. Conclusions: It can be concluded that the effect of fried potato chips on the development of retina in rats may be due to the presence of acrylamide or its metabolite.

  16. Imaging the response of the retina to electrical stimulation with genetically encoded calcium indicators.

    Science.gov (United States)

    Weitz, Andrew C; Behrend, Matthew R; Lee, Nan Sook; Klein, Ronald L; Chiodo, Vince A; Hauswirth, William W; Humayun, Mark S; Weiland, James D; Chow, Robert H

    2013-04-01

    Epiretinal implants for the blind are designed to stimulate surviving retinal neurons, thus bypassing the diseased photoreceptor layer. Single-unit or multielectrode recordings from isolated animal retina are commonly used to inform the design of these implants. However, such electrical recordings provide limited information about the spatial patterns of retinal activation. Calcium imaging overcomes this limitation, as imaging enables high spatial resolution mapping of retinal ganglion cell (RGC) activity as well as simultaneous recording from hundreds of RGCs. Prior experiments in amphibian retina have demonstrated proof of principle, yet experiments in mammalian retina have been hindered by the inability to load calcium indicators into mature mammalian RGCs. Here, we report a method for labeling the majority of ganglion cells in adult rat retina with genetically encoded calcium indicators, specifically GCaMP3 and GCaMP5G. Intravitreal injection of an adeno-associated viral vector targets ∼85% of ganglion cells with high specificity. Because of the large fluorescence signals provided by the GCaMP sensors, we can now for the first time visualize the response of the retina to electrical stimulation in real-time. Imaging transduced retinas mounted on multielectrode arrays reveals how stimulus pulse shape can dramatically affect the spatial extent of RGC activation, which has clear implications in prosthetic applications. Our method can be easily adapted to work with other fluorescent indicator proteins in both wild-type and transgenic mammals.

  17. Cholesterol in mouse retina originates primarily from in situ de novo biosynthesis.

    Science.gov (United States)

    Lin, Joseph B; Mast, Natalia; Bederman, Ilya R; Li, Yong; Brunengraber, Henri; Björkhem, Ingemar; Pikuleva, Irina A

    2016-02-01

    The retina, a thin tissue in the back of the eye, has two apparent sources of cholesterol: in situ biosynthesis and cholesterol available from the systemic circulation. The quantitative contributions of these two cholesterol sources to the retinal cholesterol pool are unknown and have been determined in the present work. A new methodology was used. Mice were given separately deuterium-labeled drinking water and chow containing 0.3% deuterium-labeled cholesterol. In the retina, the rate of total cholesterol input was 21 μg of cholesterol/g retina • day, of which 15 μg of cholesterol/g retina • day was provided by local biosynthesis and 6 μg of cholesterol/g retina • day was uptaken from the systemic circulation. Thus, local cholesterol biosynthesis accounts for the majority (72%) of retinal cholesterol input. We also quantified cholesterol input to mouse brain, the organ sharing important similarities with the retina. The rate of total cerebral cholesterol input was 121 μg of cholesterol/g brain • day with local biosynthesis providing 97% of total cholesterol input. Our work addresses a long-standing question in eye research and adds new knowledge to the potential use of statins (drugs that inhibit cholesterol biosynthesis) as therapeutics for age-related macular degeneration, a common blinding disease.

  18. [Ultrastructure of melanocytes from retina and choroid of the Pacific salmon].

    Science.gov (United States)

    Zagal'skaia, E O

    2001-01-01

    The ultrastructure of the retina and choroid cells in three species of the Pacific salmon, Oncohrynchus gorbuscha, O. keta and O. masou, was studied. The structure of retina pigment cells is similar in all the three species, only a small difference was found in the percentage of lengthened and rounded forms of melanosomes. Melanocytes of the masu salmon differ also in the structure of their nuclei. The pigment cells of choroid differ from those of retina by a more extended form of melanosomes and by the presence of less rounded melanosomes. In the chum salmon retina we found electron lucent "contact vesicles", whose assignment is open to discussion. In retina pigment cells of the masu salmon smolts ready for migration, the activity of Golgi appararus rises, mitochondria and mature melanosomes increase in number. The choroid pigment cells are slightly swollen, their processes more often and deeper penetrate into the walls of vessels, down to the endothelium. Results of the experiment with the application of an artificial magnetic field (AMF) have shown that the retina and choroid pigment cells in the masu salmon fry react to the field of a certain direction. The phenomenon of magnetosensitivity of pigment cells is discussed in addition to their possible involvement in magnetoreception.

  19. 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

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

    Science.gov (United States)

    Bouskila, Joseph; Javadi, Pasha; Elkrief, Laurent; Casanova, Christian; Bouchard, Jean-François; Ptito, Maurice

    2016-01-01

    The endocannabinoid (eCB) system is widely expressed in various parts of the central nervous system, including the retina. The localization of the key eCB receptors, particularly CB1R and CB2R, has been recently reported in rodent and primate retinas with striking interspecies differences. Little 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-preserved among these species. However, expression of NAPE-PLD is circumscribed to the photoreceptor layer only in monkeys. In contrast, CB2R expression is variable across these species; in mice, CB2R is found in retinal neurons but not in glial cells; in tree shrews, CB2R is expressed in Müller cell processes of the outer retina and in retinal neurons of the inner retina; in monkeys, CB2R is restricted to Müller cells. Finally, the expression patterns of MAGL and DAGLα are differently expressed across species. Overall, these results provide evidence that the eCB system is differently expressed in the retina of these mammals and suggest a distinctive role of eCBs in visual processing.

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

    Directory of Open Access Journals (Sweden)

    Joseph Bouskila

    2016-01-01

    Full Text Available The endocannabinoid (eCB system is widely expressed in various parts of the central nervous system, including the retina. The localization of the key eCB receptors, particularly CB1R and CB2R, has been recently reported in rodent and primate retinas with striking interspecies differences. Little 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-preserved among these species. However, expression of NAPE-PLD is circumscribed to the photoreceptor layer only in monkeys. In contrast, CB2R expression is variable across these species; in mice, CB2R is found in retinal neurons but not in glial cells; in tree shrews, CB2R is expressed in Müller cell processes of the outer retina and in retinal neurons of the inner retina; in monkeys, CB2R is restricted to Müller cells. Finally, the expression patterns of MAGL and DAGLα are differently expressed across species. Overall, these results provide evidence that the eCB system is differently expressed in the retina of these mammals and suggest a distinctive role of eCBs in visual processing.

  2. Connections between atmospheric sulphuric acid and new particle formation during QUEST III–IV campaigns in Heidelberg and Hyytiälä

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    I. Riipinen

    2007-01-01

    Full Text Available This study investigates the connections between atmospheric sulphuric acid and new particle formation during QUEST III and BACCI/QUEST IV campaigns. The campaigns have been conducted in Heidelberg (2004 and Hyytiälä (2005, the first representing a polluted site surrounded by deciduous forest, and the second a rural site in a boreal forest environment. We have studied the role of sulphuric acid in particle formation and growth by determining 1 the power-law dependencies between sulphuric acid ([H2SO4], and particle concentrations (N3–6 or formation rates at 1 nm and 3 nm (J1 and J3; 2 the time delays between [H2SO4] and N3–6 or J3, and the growth rates for 1–3 nm particles; 3 the empirical nucleation coefficients A and K in relations J1=A[H2SO4] and J1=K[H2SO4]2, respectively; 4 theoretical predictions for J1 and J3 for the days when no significant particle formation is observed, based on the observed sulphuric acid concentrations and condensation sinks. In both environments, N3–6 or J3 and [H2SO4] were linked via a power-law relation with exponents typically ranging from 1 to 2. The result suggests that the cluster activation theory and kinetic nucleation have the potential to explain the observed particle formation. However, some differences between the sites existed: The nucleation coefficients were about an order of magnitude greater in Heidelberg than in Hyytiälä conditions. The time lags between J3 and [H2SO4] were consistently lower than the corresponding delays between N3–6 and [H2SO4]. The exponents in the J3∝[H2SO4 ]nJ3-connection were consistently higher than or equal to the exponents in the relation N3–6∝[H2SO4 ]nN36. In the J1 values, no significant differences were found between the observed rates on particle formation event days and the predictions on non-event days. The J3 values predicted by the cluster activation or kinetic nucleation hypotheses, on the other hand, were considerably lower on non-event days

  3. Visualization of endothelial actin cytoskeleton in the mouse retina.

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    Alessia Fraccaroli

    Full Text Available Angiogenesis requires coordinated changes in cell shape of endothelial cells (ECs, orchestrated by the actin cytoskeleton. The mechanisms that regulate this rearrangement in vivo are poorly understood - largely because of the difficulty to visualize filamentous actin (F-actin structures with sufficient resolution. Here, we use transgenic mice expressing Lifeact-EGFP to visualize F-actin in ECs. We show that in the retina, Lifeact-EGFP expression is largely restricted to ECs allowing detailed visualization of F-actin in ECs in situ. Lifeact-EGFP labels actin associated with cell-cell junctions, apical and basal membranes and highlights actin-based structures such as filopodia and stress fiber-like cytoplasmic bundles. We also show that in the skin and the skeletal muscle, Lifeact-EGFP is highly expressed in vascular mural cells (vMCs, enabling vMC imaging. In summary, our results indicate that the Lifeact-EGFP transgenic mouse in combination with the postnatal retinal angiogenic model constitutes an excellent system for vascular cell biology research. Our approach is ideally suited to address structural and mechanistic details of angiogenic processes, such as endothelial tip cell migration and fusion, EC polarization or lumen formation.

  4. Ischemic tolerance protects the rat retina from glaucomatous damage.

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    Nicolás Belforte

    Full Text Available Glaucoma is a leading cause of acquired blindness which may involve an ischemic-like insult to retinal ganglion cells and optic nerve head. We investigated the effect of a weekly application of brief ischemia pulses (ischemic conditioning on the rat retinal damage induced by experimental glaucoma. Glaucoma was induced by weekly injections of chondroitin sulfate (CS in the rat eye anterior chamber. Retinal ischemia was induced by increasing intraocular pressure to 120 mmHg for 5 min; this maneuver started after 6 weekly injections of vehicle or CS and was weekly repeated in one eye, while the contralateral eye was submitted to a sham procedure. Glaucoma was evaluated in terms of: i intraocular pressure (IOP, ii retinal function (electroretinogram (ERG, iii visual pathway function (visual evoked potentials, (VEPs iv histology of the retina and optic nerve head. Retinal thiobarbituric acid substances levels were assessed as an index of lipid peroxidation. Ischemic conditioning significantly preserved ERG, VEPs, as well as retinal and optic nerve head structure from glaucomatous damage, without changes in IOP. Moreover, ischemia pulses abrogated the increase in lipid peroxidation induced by experimental glaucoma. These results indicate that induction of ischemic tolerance could constitute a fertile avenue for the development of new therapeutic strategies in glaucoma treatment.

  5. Phenotypic and functional characterization of Bst+/− mouse retina

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    Hamidreza Riazifar

    2015-08-01

    Full Text Available The belly spot and tail (Bst+/− mouse phenotype is caused by mutations of the ribosomal protein L24 (Rpl24. Among various phenotypes in Bst+/− mice, the most interesting are its retinal abnormalities, consisting of delayed closure of choroid fissures, decreased ganglion cells and subretinal vascularization. We further characterized the Bst+/− mouse and investigated the underlying molecular mechanisms to assess the feasibility of using this strain as a model for stem cell therapy of retinal degenerative diseases due to retinal ganglion cell (RGC loss. We found that, although RGCs are significantly reduced in retinal ganglion cell layer in Bst+/− mouse, melanopsin+ RGCs, also called ipRGCs, appear to be unchanged. Pupillary light reflex was completely absent in Bst+/− mice but they had a normal circadian rhythm. In order to examine the pathological abnormalities in Bst+/− mice, we performed electron microscopy in RGC and found that mitochondria morphology was deformed, having irregular borders and lacking cristae. The complex activities of the mitochondrial electron transport chain were significantly decreased. Finally, for subretinal vascularization, we also found that angiogenesis is delayed in Bst+/− associated with delayed hyaloid regression. Characterization of Bst+/− retina suggests that the Bst+/− mouse strain could be a useful murine model. It might be used to explore further the pathogenesis and strategy of treatment of retinal degenerative diseases by employing stem cell technology.

  6. Microcystic macular edema detection in retina OCT images

    Science.gov (United States)

    Swingle, Emily K.; Lang, Andrew; Carass, Aaron; Ying, Howard S.; Calabresi, Peter A.; Prince, Jerry L.

    2014-03-01

    Optical coherence tomography (OCT) is a powerful imaging tool that is particularly useful for exploring retinal abnormalities in ophthalmological diseases. Recently, it has been used to track changes in the eye associated with neurological diseases such as multiple sclerosis (MS) where certain tissue layer thicknesses have been associated with disease progression. A small percentage of MS patients also exhibit what has been called microcystic macular edema (MME), where uid collections that are thought to be pseudocysts appear in the inner nuclear layer. Very little is known about the cause of this condition so it is important to be able to identify precisely where these pseudocysts occur within the retina. This identi cation would be an important rst step towards furthering our understanding. In this work, we present a detection algorithm to nd these pseudocysts and to report on their spatial distribution. Our approach uses a random forest classi er trained on manual segmentation data to classify each voxel as pseudocyst or not. Despite having a small sample size of ve subjects, the algorithm correctly identi es 84.6% of pseudocysts as compared to manual delineation. Finally, using our method, we show that the spatial distribution of pseudocysts within the macula are generally contained within an annulus around the fovea.

  7. Mapping a complete neural population in the retina.

    Science.gov (United States)

    Marre, Olivier; Amodei, Dario; Deshmukh, Nikhil; Sadeghi, Kolia; Soo, Frederick; Holy, Timothy E; Berry, Michael J

    2012-10-24

    Recording simultaneously from essentially all of the relevant neurons in a local circuit is crucial to understand how they collectively represent information. Here we show that the combination of a large, dense multielectrode array and a novel, mostly automated spike-sorting algorithm allowed us to record simultaneously from a highly overlapping population of >200 ganglion cells in the salamander retina. By combining these methods with labeling and imaging, we showed that up to 95% of the ganglion cells over the area of the array were recorded. By measuring the coverage of visual space by the receptive fields of the recorded cells, we concluded that our technique captured a neural population that forms an essentially complete representation of a region of visual space. This completeness allowed us to determine the spatial layout of different cell types as well as identify a novel group of ganglion cells that responded reliably to a set of naturalistic and artificial stimuli but had no measurable receptive field. Thus, our method allows unprecedented access to the complete neural representation of visual information, a crucial step for the understanding of population coding in sensory systems.

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

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    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.

  9. 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.

  10. Feedback synaptic interaction in the dragonfly ocellar retina

    Science.gov (United States)

    1978-01-01

    The intracellular response of the ocellar nerve dendrite, the second order neuron in the retina of the dragonfly ocellus, has been modified by application of various drugs and a model developed to explain certain features of that response. Curare blocked the response completely. Both picrotoxin and bicuculline eliminated the "off" overshoot. Bicuculline also decreased the size of response and the sensitivity. gamma-Aminobutyric acid (GABA), however, increased the size of response. The evidence indicates the possibility that the receptor transmitter is acetylcholine and is inhibitory to the ocellar nerve dendrite whereas the feedback transmitter from the ocellar nerve dendrite may be GABA and is facilitory to receptor transmitter release. The model of synaptic feedback interaction developed to be consistent with these results has certain important features. It suggests that the feedback transmitter is released in the dark to increase input sensitivity from receptors in response to dim light. This implies that the dark potential of the ocellar nerve dendrite may be determined by a dynamic equilibrium established by synaptic interaction between it and the receptor terminals. Such a system is also well suited to signalling phasic information about changes in level of illumination over a wide range of intensities, a characteristic which appears to be a significant feature of the dragonfly median ocellar response. PMID:205624

  11. Mouse embryonic retina delivers information controlling cortical neurogenesis.

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    Ciro Bonetti

    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.

  12. Comparison of Diode and Argon Laser Lesions in Rabbit Retina

    Institute of Scientific and Technical Information of China (English)

    Hui Zhang; Xiaoxin Li; Bin Li; Jiping Da

    2004-01-01

    Purpose: To compare the histological alteration of retina with various spot intensities between diode and argon lasers in order to instruct the clinical use of 810 nm diode laser.Methods: Transpupillary retinal photocoagulations were performed on 42 eyes of 27pigmented rabbits. Histopathologic alteration of lesions in different intensities and different time intervals after irradiation produced by diode and argon laser was observed and compared using light microscopy. Areas of various lesions measured by image analysis system (CMIAS) were compared quantitatively.Results: Histopathologically, two-week-old grade 2 lesions produced by diode laser induced the disappearance of outer nuclear cells. More than a half of all showed reduction in number of outer nuclear layer cells in argon. Fibroblasts appeared in the diode grade 3lesions 5 days after irradiation. CMIAS data showed that all the areas of diode lesions immediately after photocoagulation were to be larger than those of argon laser lesions in the same spot intensity (P < 0.05). However, twenty-four hours after photocoagulation, the area of the diode lesions increased less than that of the argon laser lesions (8%vs.23%).Conclusion: The acute histological effect caused by 810 nm diode laser and argon green laser is similar,while the expansion of lesion area 24 hours after photocoagulation was less with the diode laser compared to the argon. This may be the first report in the literature regarding quantitative analysis of the delayed reaction of argon green lasers.

  13. Spare the rods and spoil the retina: revisited.

    Science.gov (United States)

    Sivaprasad, S; Arden, G

    2016-02-01

    Visual function improves with oxygen inhalation in people with diabetes even in the absence of visible retinopathy. Rods consume the most oxygen in the retina due to the high metabolic activity required to maintain the dark current. Therefore, Arden hypothesized that in diabetes where oxygen supply may also be affected due to the changes in retinal vasculature, prevention of dark adaptation may be a viable option to prevent or decrease the rate of progression of diabetic retinopathy. Animal experiments have proven that the absence of rods decreases the development of retinal neovascularisation. The same principle applies to panretinal photocoagulation, an established treatment for proliferative diabetic retinopathy. Recently, a few clinical studies have also shown that preventing dark adaptation by suppressing rods with 500-nm light source at night decreases the rate of progression of early diabetic retinopathy and maculopathy in the short-term. We await the results of a large two-year multi-centre trial (CLEOPATRA trial) to evaluate the long-term effects of decreasing dark adaptation by applying a 500nm light source as a mask over eyes with non-central diabetic macular oedema.

  14. Evaluation of interprofessional education: lessons learned through the development and implementation of an interprofessional seminar on team communication for undergraduate health care students in Heidelberg - a project report.

    Science.gov (United States)

    Berger, Sarah; Mahler, Cornelia; Krug, Katja; Szecsenyi, Joachim; Schultz, Jobst-Hendrik

    2016-01-01

    Einleitung: Dieser Projektbericht beschreibt die Entwicklung, Pilotierung und Evaluation eines interprofessionellen Seminars zur Team-Kommunikation, das Studierende der Humanmedizin und Studierende des Studiengangs Interprofessionelle Gesundheitsversorgung B.Sc. an der Medizinische Fakultät der Universität Heidelberg zusammengebracht hat.Projektbeschreibung: Ein fünfköpfiges interprofessionelles Team arbeitete zusammen an diesem Projekt. Kolbs Theorie des erfahrungsorientierten Lernens bildete die theoretische Grundlage für das Seminar, in dem drei interprofessionelle Kompetenzdomänen vermittelt wurden: Teamarbeit, Kommunikation und Werte/Ethik. Die Evaluation zum Zwecke der Qualitätssicherung und der zukünftigen curricularen Entwicklung wurde mit zwei quantitativen Instrumenten durchgeführt:deskriptive Analyse eines standardisierten Kurs-Bewertungsinstruments (EvaSys) Varianzanalyse (ANOVA) der deutschen Version des Fragebogens „University of the West of England Interprofessional Questionnaire“ (UWE-IP-D).Ergebnisse: Das Hauptergebnis der standardisierten Kursevaluation war, dass die interprofessionellen Seminare positiver bewertet wurden [MW=2,11 (Bereich: 1 sehr positiv bis 5 sehr negativ), SD=1, n=27] als die monoprofessionellen Seminare [MW=2,55, SD=0,98, n=90]. Der Vergleich der Vorher-/Nachher-Ergebnisse in der UWE-IP-D Befragung der interprofessionellen (IP) (n=40) und monoprofessionellen (MP) Gruppen (n=34) zeigte signifikante positive Veränderungen der Mittelwerte für beide Gruppen hinsichtlich Kommunikation, Teamarbeit und interprofessionellem Lernen. Schlussfolgerungen: Erkenntnisgewinne aus dem Projekt: a) Nutzen einer pragmatischen Vorgehensweise bei der Einführung interprofessioneller Ausbildungssequenzen, die es ermöglichte, dass verschiedene Barrieren bzgl. Logistik sowie Einstellung/Haltung überwunden werden konnten; b) eine quantitative Evaluation allein konnte die positiven Rückmeldungen des interprofessionellen Settings nicht

  15. Treatment of pediatric patients and young adults with particle therapy at the Heidelberg Ion Therapy Center (HIT: establishment of workflow and initial clinical data

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    Combs Stephanie E

    2012-10-01

    Full Text Available Abstract Background To report on establishment of workflow and clinical results of particle therapy at the Heidelberg Ion Therapy Center. Materials and methods We treated 36 pediatric patients (aged 21 or younger with particle therapy at HIT. Median age was 12 years (range 2-21 years, five patients (14% were younger than 5 years of age. Indications included pilocytic astrocytoma, parameningeal and orbital rhabdomyosarcoma, skull base and cervical chordoma, osteosarcoma and adenoid-cystic carcinoma (ACC, as well as one patient with an angiofibroma of the nasopharynx. For the treatment of small children, an anesthesia unit at HIT was established in cooperation with the Department of Anesthesiology. Results Treatment concepts depended on tumor type, staging, age of the patient, as well as availability of specific study protocols. In all patients, particle radiotherapy was well tolerated and no interruptions due to toxicity had to be undertaken. During follow-up, only mild toxicites were observed. Only one patient died of tumor progression: Carbon ion radiotherapy was performed as an individual treatment approach in a child with a skull base recurrence of the previously irradiated rhabdomyosarcoma. Besides this patient, tumor recurrence was observed in two additional patients. Conclusion Clinical protocols have been generated to evaluate the real potential of particle therapy, also with respect to carbon ions in distinct pediatric patient populations. The strong cooperation between the pediatric department and the department of radiation oncology enable an interdisciplinary treatment and stream-lined workflow and acceptance of the treatment for the patients and their parents.

  16. Comparison of the diagnostic ability of Moorfield′s regression analysis and glaucoma probability score using Heidelberg retinal tomograph III in eyes with primary open angle glaucoma

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    Jindal Shveta

    2010-01-01

    Full Text Available Purpose: To compare the diagnostic performance of the Heidelberg retinal tomograph (HRT glaucoma probability score (GPS with that of Moorfield′s regression analysis (MRA. Materials and Methods: The study included 50 eyes of normal subjects and 50 eyes of subjects with early-to-moderate primary open angle glaucoma. Images were obtained by using HRT version 3.0. Results: The agreement coefficient (weighted k for the overall MRA and GPS classification was 0.216 (95% CI: 0.119 - 0.315. The sensitivity and specificity were evaluated using the most specific (borderline results included as test negatives and least specific criteria (borderline results included as test positives. The MRA sensitivity and specificity were 30.61 and 98% (most specific and 57.14 and 98% (least specific. The GPS sensitivity and specificity were 81.63 and 73.47% (most specific and 95.92 and 34.69% (least specific. The MRA gave a higher positive likelihood ratio (28.57 vs. 3.08 and the GPS gave a higher negative likelihood ratio (0.25 vs. 0.44.The sensitivity increased with increasing disc size for both MRA and GPS. Conclusions: There was a poor agreement between the overall MRA and GPS classifications. GPS tended to have higher sensitivities, lower specificities, and lower likelihood ratios than the MRA. The disc size should be taken into consideration when interpreting the results of HRT, as both the GPS and MRA showed decreased sensitivity for smaller discs and the GPS showed decreased specificity for larger discs.

  17. Generating 3D anatomically detailed models of the retina from OCT data sets: implications for computational modelling

    Science.gov (United States)

    Shalbaf, Farzaneh; Dokos, Socrates; Lovell, Nigel H.; Turuwhenua, Jason; Vaghefi, Ehsan

    2015-12-01

    Retinal prosthesis has been proposed to restore vision for those suffering from the retinal pathologies that mainly affect the photoreceptors layer but keep the inner retina intact. Prior to costly risky experimental studies computational modelling of the retina will help to optimize the device parameters and enhance the outcomes. Here, we developed an anatomically detailed computational model of the retina based on OCT data sets. The consecutive OCT images of individual were subsequently segmented to provide a 3D representation of retina in the form of finite elements. Thereafter, the electrical properties of the retina were modelled by implementing partial differential equation on the 3D mesh. Different electrode configurations, that is bipolar and hexapolar configurations, were implemented and the results were compared with the previous computational and experimental studies. Furthermore, the possible effects of the curvature of retinal layers on the current steering through the retina were proposed and linked to the clinical observations.

  18. [Radiation preconditioning of mouse retina results in tolerance to MNU-induced degeneration and stimulates retinal recovery].

    Science.gov (United States)

    Tronov, V A; Vinogradova, Yu V; Poplinskaya, V A; Nekrasova, E I; Ostrovsky, M A

    2015-01-01

    Emerging body of data indicate protecting effect of low level of stress (preconditioning) on retina. Our previous studies have revealed a non-linear dose-response relationship for cytotoxic effect of both ionizing radiation and N-methyl-N-nitrosourea (MNU) on mouse retina. Moreover, non-cytotoxic dose of MNU increased tolerance of retina to following challenge dose of MNU. This result displays protection of retina through mechanism of recovery. In the present study we used the mouse model for MNU-induced retinal degeneration to evaluate the adaptive response of the retina to proton irradiation and implication of glial Muller cells in this response. In this paper, we have shown that the recovery of the retina after exposure to genotoxic agents is associated with an increased efficiency of DNA damage repair and lowered death of retinal photoreceptors.

  19. Neural retina identity is specified by lens-derived BMP signals.

    Science.gov (United States)

    Pandit, Tanushree; Jidigam, Vijay K; Patthey, Cedric; Gunhaga, Lena

    2015-05-15

    The eye has served as a classical model to study cell specification and tissue induction for over a century. Nevertheless, the molecular mechanisms that regulate the induction and maintenance of eye-field cells, and the specification of neural retina cells are poorly understood. Moreover, within the developing anterior forebrain, how prospective eye and telencephalic cells are differentially specified is not well defined. In the present study, we have analyzed these issues by manipulating signaling pathways in intact chick embryo and explant assays. Our results provide evidence that at blastula stages, BMP signals inhibit the acquisition of eye-field character, but from neural tube/optic vesicle stages, BMP signals from the lens are crucial for the maintenance of eye-field character, inhibition of dorsal telencephalic cell identity and specification of neural retina cells. Subsequently, our results provide evidence that a Rax2-positive eye-field state is not sufficient for the progress to a neural retina identity, but requires BMP signals. In addition, our results argue against any essential role of Wnt or FGF signals during the specification of neural retina cells, but provide evidence that Wnt signals together with BMP activity are sufficient to induce cells of retinal pigment epithelial character. We conclude that BMP activity emanating from the lens ectoderm maintains eye-field identity, inhibits telencephalic character and induces neural retina cells. Our findings link the requirement of the lens ectoderm for neural retina specification with the molecular mechanism by which cells in the forebrain become specified as neural retina by BMP activity.

  20. [Finite element analysis of temperature field of retina by electrical stimulation with microelectrode array].

    Science.gov (United States)

    Wang, Wei; Qiao, Qingli; Gao, Weiping; Wu, Jun

    2014-12-01

    We studied the influence of electrode array parameters on temperature distribution to the retina during the use of retinal prosthesis in order to avoid thermal damage to retina caused by long-term electrical stimulation. Based on real epiretinal prosthesis, a three-dimensional model of electrical stimulation for retina with 4 X 4 microelectrode array had been established using the finite element software (COMSOL Multiphysics). The steady-state temperature field of electrical stimulation of the retina was calculated, and the effects of the electrode parameters such as the distance between the electrode contacts, the materials and area of the electrode contact on temperature field were considered. The maximum increase in the retina steady temperature was about 0. 004 degrees C with practical stimulation current. When the distance between the electrode contacts was changed from 130 microm to 520 microm, the temperature was reduced by about 0.006 microC. When the contact radius was doubled from 130 microm to 260 microm, the temperature decrease was about 0.005 degrees C. It was shown that there were little temperature changes in the retina with a 4 x 4 epiretinal microelectrode array, reflecting the safety of electrical stimulation. It was also shown that the maximum temperature in the retina decreased with increasing the distance between the electrode contacts, as well as increasing the area of electrode contact. However, the change of the maximum temperature was very small when the distance became larger than the diameter of electrode contact. There was no significant difference in the effects of temperature increase among the different electrode materials. Rational selection of the distance between the electrode contacts and their area in electrode design can reduce the temperature rise induced by electrical stimulation.

  1. Immunolocalization of the P2X4 receptor on neurons and glia in the mammalian retina.

    Science.gov (United States)

    Ho, T; Vessey, K A; Fletcher, E L

    2014-09-26

    Extracellular adenosine 5'-triphosphate (eATP) acts as a neurotransmitter within the retina and brain, activating a range of ionotropic P2X and metabotropic P2Y receptors. In this study, the specific localization of the P2X4 receptor (P2X4-R) subunit was evaluated in the retina using fluorescence immunohistochemistry and pre-embedding immuno-electron microscopy. Punctate P2X4-R labeling was largely localized to the inner and outer plexiform layers of mouse, rat and cat retinae. In the mouse outer retina, double-labeling of P2X4-R with the horizontal cell marker, calbindin, revealed P2X4-R immunoreactivity (P2X4-R-IR) on horizontal cell somata and processes. In the inner retina, P2X4-R expression was found closely associated with rod and cone bipolar cell terminals, and the punctate labeling was observed on calretinin-positive amacrine cells. Using immuno-electron microscopy, P2X4-Rs were observed on processes post-synaptic to photoreceptor and bipolar cell terminals, likely representing horizontal, amacrine and ganglion cells, respectively. Furthermore, P2X4-R expression was also observed on Müller cells, astrocytes and microglia. These data suggest a role for P2X4-Rs in the lateral inhibitory pathways of the retina, modulating neuronal function of photoreceptors and bipolar cells. The expression on macro- and microglial cells implicates a role for P2X4-Rs in glial signaling, tissue homeostasis and immunosurveillance within the mammalian retina.

  2. Expression of inducible nitric oxide synthase (iNOS) in microglia of the developing quail retina.

    Science.gov (United States)

    Sierra, Ana; Navascués, Julio; Cuadros, Miguel A; Calvente, Ruth; Martín-Oliva, David; Ferrer-Martín, Rosa M; Martín-Estebané, María; Carrasco, María-Carmen; Marín-Teva, José L

    2014-01-01

    Inducible nitric oxide synthase (iNOS), which produce large amounts of nitric oxide (NO), is induced in macrophages and microglia in response to inflammatory mediators such as LPS and cytokines. Although iNOS is mainly expressed by microglia that become activated in different pathological and experimental situations, it was recently reported that undifferentiated amoeboid microglia can also express iNOS during normal development. The aim of this study was to investigate the pattern of iNOS expression in microglial cells during normal development and after their activation with LPS by using the quail retina as model. iNOS expression was analyzed by iNOS immunolabeling, western-blot, and RT-PCR. NO production was determined by using DAR-4M AM, a reliable fluorescent indicator of subcellular NO production by iNOS. Embryonic, postnatal, and adult in situ quail retinas were used to analyze the pattern of iNOS expression in microglial cells during normal development. iNOS expression and NO production in LPS-treated microglial cells were investigated by an in vitro approach based on organotypic cultures of E8 retinas, in which microglial cell behavior is similar to that of the in situ retina, as previously demonstrated in our laboratory. We show here that amoeboid microglia in the quail retina express iNOS during normal development. This expression is stronger in microglial cells migrating tangentially in the vitreal part of the retina and is downregulated, albeit maintained, when microglia differentiate and become ramified. LPS treatment of retina explants also induces changes in the morphology of amoeboid microglia compatible with their activation, increasing their lysosomal compartment and upregulating iNOS expression with a concomitant production of NO. Taken together, our findings demonstrate that immature microglial cells express iNOS during normal development, suggesting a certain degree of activation. Furthermore, LPS treatment induces overactivation of amoeboid

  3. Mechanical spectroscopy of retina explants at the protein level employing nanostructured scaffolds.

    Science.gov (United States)

    Mayazur Rahman, S; Reichenbach, Andreas; Zink, Mareike; Mayr, Stefan G

    2016-04-14

    Development of neuronal tissue, such as folding of the brain, and formation of the fovea centralis in the human retina are intimately connected with the mechanical properties of the underlying cells and the extracellular matrix. In particular for neuronal tissue as complex as the vertebrate retina, mechanical properties are still a matter of debate due to their relation to numerous diseases as well as surgery, where the tension of the retina can result in tissue detachment during cutting. However, measuring the elasticity of adult retina wholemounts is difficult and until now only the mechanical properties at the surface have been characterized with micrometer resolution. Many processes, however, such as pathological changes prone to cause tissue rupture and detachment, respectively, are reflected in variations of retina elasticity at smaller length scales at the protein level. In the present work we demonstrate that freely oscillating cantilevers composed of nanostructured TiO2 scaffolds can be employed to study the frequency-dependent mechanical response of adult mammalian retina explants at the nanoscale. Constituting highly versatile scaffolds with strong tissue attachment for long-term organotypic culture atop, these scaffolds perform damped vibrations as fingerprints of the mechanical tissue properties that are derived using finite element calculations. Since the tissue adheres to the nanostructures via constitutive proteins on the photoreceptor side of the retina, the latter are stretched and compressed during vibration of the underlying scaffold. Probing mechanical response of individual proteins within the tissue, the proposed mechanical spectroscopy approach opens the way for studying tissue mechanics, diseases and the effect of drugs at the protein level.

  4. Signals for color and achromatic contrast in the goldfish inner retina.

    Science.gov (United States)

    Burkhardt, Dwight A

    2014-11-01

    A moving stimulus paradigm was designed to investigate color contrast encoding in the retina. Recently, this paradigm yielded suggestive evidence for color contrast encoding in zebrafish but the significance and generality remain uncertain since the properties of color coding in the zebrafish inner retina are largely unknown. Here, the question of color contrast is pursued in the goldfish retina where there is much accumulated evidence for retinal mechanisms of color vision and opponent color-coding, in particular. Recordings of a sensitive local field potential of the inner retina, the proximal negative response, were made in the intact, superfused retina in the light-adapted state. Responses to color contrast and achromatic contrast were analyzed by comparing responses to a green moving bar on green versus red backgrounds. The quantitative form of the irradiance/response curves was distinctly different under a range of conditions in 32 retinas, thereby providing robust evidence for red-green color contrast. The color contrast is based on successive contrast, occurs in the absence of overt color opponency, and clearly differs from previous findings in the goldfish retina for simultaneous color contrast mediated by color-opponent neurons. The form of the irradiance/response curves suggests that successive color contrast is particularly important when achromatic contrast is low, as often occurs in natural environments. The present results provide a parallel with the well-known principle of human color vision, first proposed by Kirschmann as the third law of color contrast, and may also have implications for the evolution of vertebrate color vision.

  5. 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.

  6. Optical imaging of the retina in response to the electrical stimulation

    Science.gov (United States)

    Fujikado, Takashi; Okawa, Yoshitaka; Miyoshi, Tomomitsu; Hirohara, Yoko; Mihashi, Toshifumi; Tano, Yasuo

    2008-02-01

    Purposes: To determine if reflectance changes of the retina can be detected following electrical stimulation to the retina using a newly developed optical-imaging fundus camera. Methods: Eyes of cats were examined after pupil dilation. Retina was stimulated either focally by a ball-type electrode (BE) placed on the fenestrated sclera or diffusely using a ring-type electrode (RE) placed on the corneoscleral limbus. Electrical stimulation by biphasic pulse trains was applied for 4 seconds. Fundus images with near-infrared (800-880 nm) light were obtained between 2 seconds before and 20 seconds after the electrical stimulation (ES). A two-dimensional map of the reflectance changes (RCs) was constructed. The effect of Tetrodotoxin (TTX) was also investigated on RCs by ES using RE. Results: RCs were observed around the retinal locus where the stimulating electrodes were positioned (BE) or in the retina of the posterior pole (RE), in which the latency was about 0.5 to 1.0 sec and the peak time about 2 to 5 sec after the onset of ES. The intensity of the RCs increased with the increase of the stimulus current in both cases. RCs were completely suppressed after the injection of TTX. Conclusions: The functional changes of the retina either by focal or diffuse electrical stimulation were successfully detected by optical imaging of the retina. The contribution of retinal ganglion cells on RCs by ES was confirmed by TTX experiment. This method may be applied to the objective evaluation of the artificial retina.

  7. Circadian modulation of crustacean hyperglycemic hormone in crayfish eyestalk and retina.

    Science.gov (United States)

    Fanjul-Moles, Maria Luisa; Escamilla-Chimal, Elsa Guadalupe; Salceda, Rocio; Giulianini, Piero G; Sánchez-Chávez, Gustavo

    2010-01-01

    Previous studies suggested the retina could be a putative locus of daily crustacean hyperglycemic hormone (CHH) secretion, as it possesses its own metabolic machinery and is independent of the well-known CHH eyestalk locus responsible for the circadian secretion of this peptide. However, it has been proposed that hemolymph glucose and lactate concentrations play a dual role in the regulation of CHH in crayfish. To elucidate the temporal relationship between these two different CHH production loci and to examine their relationship with glucose regulation, we investigated the expression of CHH daily and circadian rhythms in the eyestalk and retina of crayfish using biochemical methods and time series analysis. We wanted to determine whether (1) putative retina and eyestalk CHH rhythmic expressions are correlated and if the oscillations of the two metabolic products of lactate and glucose in the blood due to CHH action on the target tissue correlate, and (2) retina CHH (RCHH) and the possible retinal substrate glycogen and its product glucose are temporally correlated. We found a negative correlation between daily and circadian changes of relative CHH abundance in the retina and eyestalk. This correlation and the cross-correlation values found between eyestalk CHH and hemolymph and glucose confirm that CHH produced by the X-organ sinus gland complex is under the previously proposed dual feedback control system over the 24 h time period. However, the presence of both glycogen and glucose in the retina, the cross-correlation values found between these parameters and hemolymph lactate and glucose, as well as RCHH and hemolymph and retina metabolic markers suggest RCHH is not under the same temporal metabolic control as eyestalk CHH. Nonetheless, their expression may be linked to common rhythms-generating processes.

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

    Science.gov (United States)

    Contartese, Daniela S.; Rolón, Federico; Sarotto, Anibal; Dorfman, Veronica B.; Loidl, Cesar F.; Martínez, Alfredo

    2016-01-01

    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. PMID:27556928

  9. Adult peripheral blood mononuclear cells transdifferentiate in vitro and integrate into the retina in vivo.

    Science.gov (United States)

    Liu, Qian; Guan, Liping; Huang, Bing; Li, Weihua; Su, Qiao; Yu, Minbin; Xu, Xiaoping; Luo, Ting; Lin, Shaochun; Sun, Xuerong; Chen, Mengfei; Chen, Xigu

    2011-06-01

    Adult peripheral blood-derived cells are able to differentiate into a variety of cell types, including nerve cells, liver-like cells and epithelial cells. However, their differentiation into retina-like cells is controversial. In the present study, transdifferentiation potential of human adult peripheral blood mononuclear cells into retina-like cells and integration into the retina of mice were investigated. Freshly isolated adult peripheral blood mononuclear cells were divided into two groups: cells in group I were cultured in neural stem cell medium, and cells in group II were exposed to conditioned medium from rat retinal tissue culture. After 5 days, several distinct cell morphologies were observed, including standard mononuclear, neurons with one or two axons and elongated glial-like cells. Immunohistochemical analysis of neural stem cell, neuron and retina cell markers demonstrated that cells in both groups were nestin-, MAP2 (microtubule-associated protein)- and GFAP (glial fibrillary acidic protein)-positive. Flow cytometry results suggested a significant increase in nestin-, MAP2- and CD16-positive cells in group I and nestin-, GFAP-, MAP2-, vimentin- and rhodopsin-positive cells in group II. To determine survival, migration and integration in vivo, cell suspensions (containing group I or group II cells) were injected into the vitreous or the peritoneum. Tissue specimens were obtained and immunostained 4 weeks after transplantation. We found that cells delivered by intravitreal injection integrated into the retina. Labelled cells were not detected in the retina of mice receiving differentiated cells by intraperitoneal injection, but cells (groups I and II) were detected in the liver and spleen. Our findings revealed that human adult peripheral blood mononuclear cells could be induced to transdifferentiate into neural precursor cells and retinal progenitor cells in vitro, and the differentiated peripheral blood mononuclear cells can migrate and integrate

  10. Microglia in the Outer Retina and their Relevance to Pathogenesis of Age-Related Macular Degeneration (AMD)

    OpenAIRE

    2012-01-01

    Age-related macular degeneration (AMD), the largest cause of legal blindness in the elderly in the Western world, is a disease whose pathogenesis is incompletely understood and for which therapeutic challenges remain. The etiology of AMD is thought to involve chronic neuroinflammation of the retina but the details of relevant cellular mechanisms are still not fully understood. Retinal microglia are the primary resident immune cell in the retina and are normally absent from the outer retina, t...

  11. Morphological Characterization and Topographic Analysis of Multiple Photoreceptor Types in the Retinae of Mesopelagic Hatchetfishes with Tubular Eyes

    OpenAIRE

    Biagioni, Lauren M.; Hunt, David M.; Collin, Shaun P.

    2016-01-01

    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, Argyropelecus affinis, and Argyropelecus aculeatus was determined using a random, un...

  12. Somatostatin-14 and somatostatin-28 levels are light-driven and vary during development in the chicken retina.

    Science.gov (United States)

    Dowton, M; Boelen, M K; Morgan, I G

    1994-03-18

    The relative levels of somatostatin-14 and somatostatin-28 were determined during both perinatal development and variations in lighting conditions in the chicken retina. During perinatal development of the retina, somatostatin-14 predominated in recently hatched chickens, whereas somatostatin-28 predominated in the retinas of older chickens. In mature chickens, the levels of both somatostatin-14 and somatostatin-28 increased during the light and decreased during the dark. Our results suggest that these two forms of somatostatin are released proportionally and in parallel.

  13. Spatiotemporal realization of an artificial retina model and performance evaluation through ISI- and spike count-based image reconstruction methods

    OpenAIRE

    2014-01-01

    Development of an artificial retina model that can mimic the biologic retina is a highly challenging task and this task is an important step in the development of a visual prosthesis. The receptive field structure of the retina layer is usually modeled as a 2D difference of Gaussian (DOG) filter profile. In the present study, as a different approach, a retina model including a 3D 2-stage DOG filter (3D-ADOG) that has an adaptively changing bandwidth with respect to the local image stati...

  14. EFFECT OF FUNDUS PIGMENT ON RESPONSE OF RABBIT RETINA TO TRANSPUPILLARY THERMOTHERAPY

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To study the effect of fundus pigment on the response of the retina to transpupillary thermotherapy (TTT). Methods The retina were irradiated with 810 nm diode laser in 16 eyes of 8 pigmented rabbits and 12 eyes of 6 albino rabbits. The spot size was 1.2 mm; the duration was 60 s; and powers were 50, 80, 150 and 300 mW for pigmented rabbits and 800, 1 200 and 1 500mW for albino rabbits. All of the eyes were followed up with ophthalmolscope. The fundus was photographed and examined histologically with optic microscope immediately and 1 month after TTT respectively. Results The changes of the fundus and the histological examination were not significant immediately and 1 month after TTT in 50 mW group of pigmented rabbit and 800 mW of albino rabbit. Grey spot on the retina was observed on the fundus in 80 mW group of pigmented rabbit and 1 200 mW of albino rabbit immediately after TTT. The structure of the retina remained intact and subretinal fluid was observed histologically. Grey spot was still visible on the fundus, though the fluid was absorbed after 1 month. As the power of diode laser was increased to 150 mW for pigmented rabbits and 1500 mW for albino rabbit, fundus white spots were observed and the outer retina was destroyed while photoreceptors existed immediately after TTT. Pigmentation was found in white lesions and the fibrous proliferation was found in choroid 1 month after TTT. Prominent white spot was seen on the fundus immediately after laser irradiation of 300 mW in pigmented rabbits and the structure of the retina was obscured. One month after TTT, dense pigmentation appeared at laser lesions. The retina was thinner. There was prominent fibrous proliferation in the choroid. Conclusion The fundus pigment seems to play an important role in the response of the retina to TTT. The reaction of the retina is in proportion to the intensity of laser.

  15. Proton and carbon ion radiotherapy for primary brain tumors delivered with active raster scanning at the Heidelberg Ion Therapy Center (HIT: early treatment results and study concepts

    Directory of Open Access Journals (Sweden)

    Rieken Stefan

    2012-03-01

    Full Text Available Abstract Background Particle irradiation was established at the University of Heidelberg 2 years ago. To date, more than 400 patients have been treated including patients with primary brain tumors. In malignant glioma (WHO IV patients, two clinical trials have been set up-one investigating the benefit of a carbon ion (18 GyE vs. a proton boost (10 GyE in addition to photon radiotherapy (50 Gy, the other one investigating reirradiation with escalating total dose schedules starting at 30 GyE. In atypical meningioma patients (WHO °II, a carbon ion boost of 18 GyE is applied to macroscopic tumor residues following previous photon irradiation with 50 Gy. This study was set up in order to investigate toxicity and response after proton and carbon ion therapy for gliomas and meningiomas. Methods 33 patients with gliomas (n = 26 and meningiomas (n = 7 were treated with carbon ion (n = 26 and proton (n = 7 radiotherapy. In 22 patients, particle irradiation was combined with photon therapy. Temozolomide-based chemotherapy was combined with particle therapy in 17 patients with gliomas. Particle therapy as reirradiation was conducted in 7 patients. Target volume definition was based upon CT, MRI and PET imaging. Response was assessed by MRI examinations, and progression was diagnosed according to the Macdonald criteria. Toxicity was classified according to CTCAE v4.0. Results Treatment was completed and tolerated well in all patients. Toxicity was moderate and included fatigue (24.2%, intermittent cranial nerve symptoms (6% and single episodes of seizures (6%. At first and second follow-up examinations, mean maximum tumor diameters had slightly decreased from 29.7 mm to 27.1 mm and 24.9 mm respectively. Nine glioma patients suffered from tumor relapse, among these 5 with infield relapses, causing death in 8 patients. There was no progression in any meningioma patient. Conclusions Particle radiotherapy is safe and feasible in patients with primary brain

  16. Contribution and significance of Heidelberg retinal tomography II in diagnostics of ocular hypertension and its conversion into primary open-angle glaucoma

    Directory of Open Access Journals (Sweden)

    Marković Vujica

    2009-01-01

    Full Text Available Background/Aim. A term 'ocular hypertension' is used when IOP is found to be > 21 mmHg on two consecutive occasions, in the absence of detectable glaucomatous damage. The aim of this study was to determine the significance and contribution of Heidelberg Retinal Tomography II (HRT II results that show very early, subtle changes in retinal neurofibre layers (RNFL in the optic nerve head that are specific for glaucoma itself (the loss of neuroretinal rim area and an increase of Cup/Disc ratio, but are not possible to register by an ophthalmoscope. Also, when the results of the functional tests remain unchanged, that confirms the conversion of ocular hypertension into glaucoma. Methods. During a 5-year study period (2002-2007, 29 patients with ocular hypertension were examined. The frequency of control examinations, based on the presence of risk factors for glaucoma development, was 3-6 months. The examination also included IOP measurements with Goldmann Applanation Tonometry (GAT, central corneal thickness (CCT determination by pachymetry, the examination of chamber angle using indirect gonioscopy, visual field tests by computerized perimetry and also papillae nervi optici (PNO examination by using HRT II. The application of HRT II enables a great number of stereometric parameters of optic disc, the most important being the rim area and Cup/Disc (C/D ratio, which was followed during the control examination by each segment, as well as PNO in global. Results. In the examination period, three cases of conversion of ocular hypertension into a primary open-angle glaucoma were found. In the group of patients with ocular hypertension, HRT II results after six months did not show a significant increase in C/D ratio. No significant loss of rim area or rim volume was found either. In three cases of conversion, HRT II results after 3 months showed an increase of C/D ratio and also a significant loss in rim volume at first examination (0.413 comparing to the

  17. Light-dark condition regulates sirtuin mRNA levels in the retina.

    Science.gov (United States)

    Ban, Norimitsu; Ozawa, Yoko; Inaba, Takaaki; Miyake, Seiji; Watanabe, Mitsuhiro; Shinmura, Ken; Tsubota, Kazuo

    2013-11-01

    Sirtuins (Sirt1-7) are nicotinamide adenine dinucleotide (NAD)-dependent protein deacetylases/ADP-ribosyltransferases that modulate many metabolic responses affecting aging. Sirtuins expressed in tissues and organs involved in systemic metabolism have been extensively studied. However, the characteristics of sirtuins in the retina, where local energy expenditure changes dynamically in response to light stimuli, are largely unknown. Here we analyzed sirtuin mRNA levels by real-time PCR, and found that all seven sirtuins are highly expressed in the retina compared with other tissues, such as liver. We then analyzed the sirtuin mRNA profiles in the retina over time, under a 12-h light/12-h dark cycle (LD condition) and in constant darkness (DD condition). All seven sirtuins showed significant daily variation under the LD condition, with all except Sirt6 being increased in the dark phase. The expression patterns were different under the DD condition, suggesting that sirtuin mRNA levels except Sirt6 are affected by light-dark condition. These findings were not obtained in the brain and liver. In addition, the mRNA expression patterns of Nicotinamide phosphoribosyltransferase (Nampt), peroxisome proliferator-activated receptor gamma coactivator (PGC1α), and transcription factor A, mitochondrial (Tfam) in the retina, were similar to those of the sirtuins except Sirt6. Our observations provide new insights into the metabolic mechanisms of the retina and the sirtuins' regulatory systems.

  18. Spatiotemporal distribution of 1P1 antigen expression in the plexiform layers of developing chick retina

    Institute of Scientific and Technical Information of China (English)

    WANGHOUHUA; QIUBAOSONG; 等

    1993-01-01

    Changes in the distribution of 1P1-antigen in the developing chick retina have been examined by indriect immunofluorescence staining technique using the novel monoclonal antibody(MAb)1P1.Expression of the 1P1 antigen was found to be regulated in radial as well as in tangential dimension of the retina,being preferentially or exclusively located in the inner and outer plexiform layers of the neural retina depending on the stages of development ,With the onset of the formation of the inner plexiform layer 1P1 antigen becomes expressed in the retina.With progressing differentiation of the inner plexiform layer 1P1 immunofluorescence revealed 2 subbands at E9 and 6 subands at E18,At postnatal stages(after P3) immunoreactivity was reduced in an inside-outside sequence leading to the complete absence of the 1P1 antigen in adulthood.1P1 antigen expression in the outer plexiform layer was also subject to developmental regulation.The spation-temporal pattern of 1P1 antigen expression was correlated with the time course of histological differentation of chick retina,namely the synapse rich plexiform layers.Whether the 1P1 antigen was functionally involved in dendrite extension and synapse formation was discussed.

  19. Pathways of cholesterol homeostasis in mouse retina responsive to dietary and pharmacologic treatments.

    Science.gov (United States)

    Zheng, Wenchao; Mast, Natalia; Saadane, Aicha; Pikuleva, Irina A

    2015-01-01

    Effects of serum cholesterol on cholesterol content in the retina are currently unknown. It is also unclear how cholesterol levels are controlled in the retina. High-cholesterol diet and oral administrations of simvastatin were used to modulate serum cholesterol in mice. These treatments only modestly affected cholesterol content in the retina and had no significant effect on retinal expression of the major cholesterol- and vision-related genes; the sterol-regulatory element binding protein pathway of transcriptional regulation does not seem to be operative in the retina under the experimental conditions used. Evidence is obtained that posttranslational mechanisms play a role in the control of retinal cholesterol. Retinal genes were only upregulated by oral administrations of TO901317 activating liver X receptors. Three of the upregulated genes could be of particular importance (apoD, Idol, and Rpe65) and have not yet been considered in the context of cholesterol homeostasis in the retina. Collectively, the data obtained identify specific features of retinal cholesterol maintenance and suggest additional therapies for age-related macular degeneration, a blinding disease characterized by cholesterol and lipid accumulations in chorioretinal tissues.

  20. Changes in growth factor expression in normal aging of the rat retina.

    Science.gov (United States)

    Smith, Christopher P; Steinle, Jena J

    2007-12-01

    Although much is known about the growth factor changes in ocular tissues during various diseases, little is known about normal aging of the retina. In order to further understand normal aging in the retina, we characterized age-related changes of growth factor expression in three different ages of rat retina. Real time PCR and protein analysis was conducted to investigate steady state mRNA expression and protein levels of VEGF, VEGFR2, PEDF, Ang-1, Tie-2, EphB4 and ephrinB2 in the retina of 8-, 22-, and 32-month-old Brown Norway X Fischer 344 F1 hybrid rats. An increase of VEGF protein levels was found at 32months compared to 8 and 22months of age. VEGFR2 protein was found to be increased at 22 and 32months compared to 8months. PEDF protein levels were reduced at 22 and 32months. Tie-2 levels were found to be significantly decreased by 32months compared to 8months of age, while ephrinB2 was found to be significantly lower at both 22 and 32months compared to 8months of age. The increases found in VEGF and its receptor VEGFR2, with the simultaneous decrease of PEDF protein levels, may stimulate an environment that is well suited for neovascularization in the normal aging retina. Overall, these results suggest that normal aging produces substantial changes in gene expression and protein levels.

  1. Circadian and Dopaminergic Regulation of Fatty Acid Oxidation Pathway Genes in Retina and Photoreceptor Cells

    Science.gov (United States)

    Vancura, Patrick; Wolloscheck, Tanja; Baba, Kenkichi; Tosini, Gianluca; Iuvone, P. Michael; Spessert, Rainer

    2016-01-01

    The energy metabolism of the retina might comply with daily changes in energy demand and is impaired in diabetic retinopathy—one of the most common causes of blindness in Europe and the USA. The aim of this study was to investigate putative adaptation of energy metabolism in healthy and diabetic retina. Hence expression analysis of metabolic pathway genes was performed using quantitative polymerase chain reaction, semi-quantitative western blot and immunohistochemistry. Transcriptional profiling of key enzymes of energy metabolism identified transcripts of mitochondrial fatty acid β-oxidation enzymes, i.e. carnitine palmitoyltransferase-1α (Cpt-1α) and medium chain acyl-CoA dehydrogenase (Acadm) to display daily rhythms with peak values during daytime in preparations of the whole retina and microdissected photoreceptors. The cycling of both enzymes persisted in constant darkness, was dampened in mice deficient for dopamine D4 (D4) receptors and was altered in db/db mice—a model of diabetic retinopathy. The data of the present study are consistent with circadian clock-dependent and dopaminergic regulation of fatty acid oxidation in retina and its putative disturbance in diabetic retina. PMID:27727308

  2. Retinal degeneration progression changes lentiviral vector cell targeting in the retina.

    Directory of Open Access Journals (Sweden)

    Maritza Calame

    Full Text Available In normal mice, the lentiviral vector (LV is very efficient to target the RPE cells, but transduces retinal neurons well only during development. In the present study, the tropism of LV has been investigated in the degenerating retina of mice, knowing that the retina structure changes during degeneration. We postulated that the viral transduction would be increased by the alteration of the outer limiting membrane (OLM. Two different LV pseudotypes were tested using the VSVG and the Mokola envelopes, as well as two animal models of retinal degeneration: light-damaged Balb-C and Rhodopsin knockout (Rho-/- mice. After light damage, the OLM is altered and no significant increase of the number of transduced photoreceptors can be obtained with a LV-VSVG-Rhop-GFP vector. In the Rho-/- mice, an alteration of the OLM was also observed, but the possibility of transducing photoreceptors was decreased, probably by ongoing gliosis. The use of a ubiquitous promoter allows better photoreceptor transduction, suggesting that photoreceptor-specific promoter activity changes during late stages of photoreceptor degeneration. However, the number of targeted photoreceptors remains low. In contrast, LV pseudotyped with the Mokola envelope allows a wide dispersion of the vector into the retina (corresponding to the injection bleb with preferential targeting of Müller cells, a situation which does not occur in the wild-type retina. Mokola-pseudotyped lentiviral vectors may serve to engineer these glial cells to deliver secreted therapeutic factors to a diseased area of the retina.

  3. 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...... components (Müller cells). The aim of this study was to determine the expression pattern of GPR55 in the monkey retina by using confocal microscopy. Our results show that GPR55 is strictly localized in the photoreceptor layer of the extrafoveal portion of the retina. Co-immunolabeling of GPR55 with rhodopsin...... in cones. The labeling of GPR55 in rods was further assessed with a 3D visualization in the XZ and YZ planes thus confirming its exclusive expression in rods. These results provide data on the distribution of GPR55 in the monkey retina, different than CB1R and CB2R. The presence of GPR55 in rods suggests...

  4. Zebrafish Cx35: cloning and characterization of a gap junction gene highly expressed in the retina.

    Science.gov (United States)

    McLachlan, Elizabeth; White, Thomas W; Ugonabo, Chioma; Olson, Carl; Nagy, James I; Valdimarsson, Gunnar

    2003-09-15

    The vertebrate connexin gene family encodes protein subunits of gap junction channels, which provide a route for direct intercellular communication. Consequently, gap junctions play a vital role in many developmental and homeostatic processes. Aberrant functioning of gap junctions is implicated in many human diseases. Zebrafish are an ideal vertebrate model to study development of the visual system as they produce transparent embryos that develop rapidly, thereby facilitating morphological and behavioral testing. In this study, zebrafish connexin35 has been cloned from a P1 artificial chromosome (PAC) library. Sequence analysis shows a high degree of similarity to the Cx35/36 orthologous group, which are expressed primarily in nervous tissue, including the retina. The gene encodes a 304-amino acid protein with a predicted molecular weight of approximately 35 kDa. Injection of zebrafish Cx35 RNA into paired Xenopus oocytes elicited intercellular electrical coupling with weak voltage sensitivity. In development, Cx35 is first detectable by Northern analysis and RT-PCR, at 2 days post-fertilization (2 dpf), and in the adult it is expressed in the brain and retina. Immunohistochemical analysis revealed that the Cx35 protein is expressed in two sublaminae of the inner plexiform layer of the adult retina. A similar pattern was seen in the 4 and 5 dpf retina, but no labeling was detected in the retina of earlier embryos.

  5. The lens controls cell survival in the retina: Evidence from the blind cavefish Astyanax.

    Science.gov (United States)

    Strickler, Allen G; Yamamoto, Yoshiyuki; Jeffery, William R

    2007-11-15

    The lens influences retinal growth and differentiation during vertebrate eye development but the mechanisms are not understood. The role of the lens in retinal growth and development was studied in the teleost Astyanax mexicanus, which has eyed surface-dwelling (surface fish) and blind cave-dwelling (cavefish) forms. A lens and laminated retina initially develop in cavefish embryos, but the lens dies by apoptosis. The cavefish retina is subsequently disorganized, apoptotic cells appear, the photoreceptor layer degenerates, and retinal growth is arrested. We show here by PCNA, BrdU, and TUNEL labeling that cell proliferation continues in the adult cavefish retina but the newly born cells are removed by apoptosis. Surface fish to cavefish lens transplantation, which restores retinal growth and rod cell differentiation, abolished apoptosis in the retina but not in the RPE. Surface fish lens deletion did not cause apoptosis in the surface fish retina or affect RPE differentiation. Neither lens transplantation in cavefish nor lens deletion in surface fish affected retinal cell proliferation. We conclude that the lens acts in concert with another optic component, possibly the RPE, to promote retinal cell survival. Accordingly, deficiency in both optic structures may lead to eye degeneration in cavefish.

  6. Presence and distribution of histaminergic components in rat and bovine retina.

    Science.gov (United States)

    Arbonés, L; García-Verdugo, J; Picatoste, F; García, A

    1988-01-01

    The presence of histamine and its related enzymes, histidine decarboxylase and histamine N-methyltransferase and the subcellular distribution of the amine and of H(1)-receptors were studied in the retina of two mammalian species. Histamine is present in rat and bovine retinas in concentrations (113 +/- 10 and 72 +/- 9 ng/g wet tissue, respectively) similar to those found in the brain. Histological examination and release experiments with Compound 48/80 performed in rat retina indicate a non mast cell location for the amine. Histidine decarboxylase and histamine N-methyltransferase activities in rat and bovine retinas were also comparable to those found in brain cortex suggesting that histamine can be synthesized and catabolyzed in situ. Subcellular fractionation of bovine retina showed that both the amine and H(1)-receptors are concentrated in particulate fractions where small sized synaptosomes sediment, presumably derived from horizontal and amacrine cells. These results are in agreement with a neurotransmitter or neuromodulator role for histamine in cells of the retinal inner nuclear layer.

  7. Identification of Novel Regulators of atonal Expression in the Developing Drosophila Retina

    Science.gov (United States)

    Melicharek, David; Shah, Arpit; DiStefano, Ginnene; Gangemi, Andrew J.; Orapallo, Andrew; Vrailas-Mortimer, Alysia D.; Marenda, Daniel R.

    2008-01-01

    Atonal is a Drosophila proneural protein required for the proper formation of the R8 photoreceptor cell, the founding photoreceptor cell in the developing retina. Proper expression and refinement of the Atonal protein is essential for the proper formation of the Drosophila adult eye. In vertebrates, expression of transcription factors orthologous to Drosophila Atonal (MATH5/Atoh7, XATH5, and ATH5) and their progressive restriction are also involved in specifying the retinal ganglion cell, the founding neural cell type in the mammalian retina. Thus, identifying factors that are involved in regulating the expression of Atonal during development are important to fully understand how retinal neurogenesis is accomplished. We have performed a chemical mutagenesis screen for autosomal dominant enhancers of a loss-of-function atonal eye phenotype. We report here the identification of five genes required for proper Atonal expression, three of which are novel regulators of Atonal expression in the Drosophila retina. We characterize the role of the daughterless, kismet, and roughened eye genes on atonal transcriptional regulation in the developing retina and show that each gene regulates atonal transcription differently within the context of retinal development. Our results provide additional insights into the regulation of Atonal expression in the developing Drosophila retina. PMID:18832354

  8. Ischemic injury leads to extracellular matrix alterations in retina and optic nerve

    Science.gov (United States)

    Reinhard, Jacqueline; Renner, Marina; Wiemann, Susanne; Shakoor, Daniel A.; Stute, Gesa; Dick, H. Burkhard; Faissner, Andreas; Joachim, Stephanie C.

    2017-01-01

    Retinal ischemia occurs in a variety of eye diseases. Restrained blood flow induces retinal damage, which leads to progressive optic nerve degeneration and vision loss. Previous studies indicate that extracellular matrix (ECM) constituents play an important role in complex tissues, such as retina and optic nerve. They have great impact on de- and regeneration processes and represent major candidates of central nervous system glial scar formation. Nevertheless, the importance of the ECM during ischemic retina and optic nerve neurodegeneration is not fully understood yet. In this study, we analyzed remodeling of the extracellular glycoproteins fibronectin, laminin, tenascin-C and tenascin-R and the chondroitin sulfate proteoglycans (CSPGs) aggrecan, brevican and phosphacan/RPTPβ/ζ in retinae and optic nerves of an ischemia/reperfusion rat model via quantitative real-time PCR, immunohistochemistry and Western blot. A variety of ECM constituents were dysregulated in the retina and optic nerve after ischemia. Regarding fibronectin, significantly elevated mRNA and protein levels were observed in the retina following ischemia, while laminin and tenascin-C showed enhanced immunoreactivity in the optic nerve after ischemia. Interestingly, CSPGs displayed significantly increased expression levels in the optic nerve. Our study demonstrates a dynamic expression of ECM molecules following retinal ischemia, which strengthens their regulatory role during neurodegeneration. PMID:28262779

  9. Long-term glial reactivity in rat retinas ipsilateral and contralateral to experimental glaucoma.

    Science.gov (United States)

    Kanamori, Akiyasu; Nakamura, Makoto; Nakanishi, Yoriko; Yamada, Yuko; Negi, Akira

    2005-07-01

    Although glaucoma is known to alter glial reactivity, the long-term effect of elevated intraocular pressure (IOP) on glial change has not been fully elucidated. This study aimed to examine how chronically elevated IOP induced by episcleral vein cauterization (EVC) in unilateral eyes affect reactivities of astrocytes and Müller cells of rats in the treated as well as contralateral eyes over time. EVC in unilateral eyes of Sprague-Dawley rats were performed to produce chronically elevated IOP. Flat mounted retina preparations were made at several points until 6 months, which were subjected to immunostaining for glial fibrillary acidic protein (GFAP). Retinal homogenates were one- or two-dimensionally electrophoresed, followed by GFAP immunoblotting. EVC significantly increased IOPs up to 27.8 from 13.1 mmHg, which gradually decreased over time. In flat mounted retinas, astrocytes lost but Müller cells gained GFAP immunoreactivity at 3 days after cauterization. The glial changes were partially reversed over time but last even after IOP normalization. In the contralateral eyes, similar glial changes gradually appeared at 1 month after EVC and thereafter. Immunoblotting demonstrated not only molecular size shifts but also alteration of isoelectric focusing of GFAP both in treated and contralateral retina as compared with age-matched control retina. EVC led to opposite reactions in astrocytes and Müller cells in terms of GFAP immunoreactivity. Late-onset glial reactivity also occurred in the contralateral retina.

  10. Patterns of cell proliferation and rod photoreceptor differentiation in shark retinas.

    Science.gov (United States)

    Ferreiro-Galve, Susana; Rodríguez-Moldes, Isabel; Anadón, Ramón; Candal, Eva

    2010-01-01

    We studied the pattern of cell proliferation and its relation with photoreceptor differentiation in the embryonic and postembryonic retina of two elasmobranchs, the lesser spotted dogfish (Scyliorhinus canicula) and the brown shyshark (Haploblepharus fuscus). Cell proliferation was studied with antibodies raised against proliferating cell nuclear antigen (PCNA) and phospho-histone-H3, and early photoreceptor differentiation with an antibody raised against rod opsin. As regards the spatiotemporal distribution of PCNA-immunoreactive cells, our results reveal a gradual loss of PCNA that coincides in a spatiotemporal sequence with the gradient of layer maturation. The presence of a peripheral growth zone containing pure-proliferating retinal progenitors (the ciliary marginal zone) in the adult retina matches with the general pattern observed in other groups of gnathostomous fishes. However, in the shark retina the generation of new cells is not restricted to the ciliary marginal zone but also occurs in retinal areas that contain differentiated cells: (1) in a transition zone that lies between the pure-proliferating ciliary marginal zone and the central (layered) retina; (2) in the differentiating central area up to prehatching embryos where large amounts of PCNA-positive cells were observed even in the inner and outer nuclear layers; (3) and in the retinal pigment epithelium of prehatching embryos. Rod opsin immunoreactivity was observed in both species when the outer plexiform layer begins to be recognized in the central retina and, as we previously observed in trout, coincided temporally with the weakening in PCNA labelling.

  11. 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.

  12. The sarcoglycan-sarcospan complex localization in mouse retina is independent from dystrophins

    Science.gov (United States)

    Fort, Patrice; Estrada, Francisco-Javier; Bordais, Agnès; Mornet, Dominique; Sahel, José-Alain; Picaud, Serge; Vargas, Haydeé Rosas; Coral-Vázquez, Ramón M.; Rendon, Alvaro

    2005-01-01

    The sarcoglycan–sarcospan (SG–SSPN) complex is part of the dystrophin-glycoprotein complex that has been extensively characterized in muscle. To establish the framework for functional studies of sarcoglycans in retina here, we quantified sarcoglycans mRNA levels with real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and performed immunohistochemistry to determine their cellular and subcellular distribution. We showed that the β-, δ-, γ-, ε-sarcoglycans and sarcospan are expressed in mouse retina. They are localized predominantly in the outer and the inner limiting membranes, probably in the Müller cells and also in the ganglion cells axons where the expression of dystrophins have never been reported. We also investigated the status of the sarcoglycans in the retina of mdx3cv mutant mice for all Duchene Muscular Dystrophy (DMD) gene products. The absence of dystrophin did not produce any change in the sarcoglycan–sarcospan components expression and distribution. PMID:15993965

  13. Differential stimulation of the retina with subretinally injected exogenous neurotransmitter: A biomimetic alternative to electrical stimulation

    Science.gov (United States)

    Rountree, Corey M.; Inayat, Samsoon; Troy, John B.; Saggere, Laxman

    2016-12-01

    Subretinal stimulation of the retina with neurotransmitters, the normal means of conveying visual information, is a potentially better alternative to electrical stimulation widely used in current retinal prostheses for treating blindness from photoreceptor degenerative diseases. Yet, no subretinal electrical or chemical stimulation study has stimulated the OFF and ON pathways differentially through inner retinal activation. Here, we demonstrate the feasibility of differentially stimulating retinal ganglion cells (RGCs) through the inner nuclear layer of the retina with glutamate, a primary neurotransmitter chemical, in a biomimetic way. We show that controlled pulsatile delivery of glutamate into the subsurface of explanted wild-type rat retinas elicits highly localized simultaneous inhibitory and excitatory spike rate responses in OFF and ON RGCs. We also present the spatiotemporal characteristics of RGC responses to subretinally injected glutamate and the therapeutic stimulation parameters. Our findings could pave the way for future development of a neurotransmitter-based subretinal prosthesis offering more naturalistic vision and better visual acuity than electrical prostheses.

  14. The mouse retina in 3D: quantification of vascular growth and remodeling.

    Science.gov (United States)

    Milde, Florian; Lauw, Stephanie; Koumoutsakos, Petros; Iruela-Arispe, M Luisa

    2013-12-01

    The mouse retina has become a prominent model for studying angiogenesis. The easy access and well-known developmental progression have significantly propelled our ability to examine and manipulate blood vessels in vivo. Nonetheless, most studies have restricted their evaluations to the superficial plexus (an upper vascular layer in contact with the vitreous). Here we present experimental data and quantification for the developmental progression of the full retina including the intermediate and deeper plexus that sprouts from the superficial layer. We analyze the origin and advancement of vertical sprouting and present the progression of vascular perfusion within the tissue. Furthermore, we introduce the use of Minkowsky functionals to quantify remodeling in the superficial and deeper plexus. The work expands information on the retina towards a 3D structure. This is of particular interest, as recent data have demonstrated differential effects of gene deletion on the upper and deeper plexus, highlighting the concept of distinct operational pathways during sprouting angiogenesis.

  15. [Role of immunological factors in peripheral vitreo-chorioretinal dystrophies and macular ruptures of the retina].

    Science.gov (United States)

    Balashova, L M; Saksonova, E O; Zaĭtseva, N S; Slepova, O S; Teplinskaia, L E; Il'nitskiĭ, V V; Grishin, V L

    1995-01-01

    The authors analyze the results of clinical and immunological examinations of patients with peripheral vitreo-chorioretinal dystrophies (PVCRD) and macular ruptures of the retina. No antibodies to S-AG were detected in the lacrimal fluid in 87.5% of patients with PVCRD without retinal defects. In patients with PVCRD with retinal defects antibodies to S-AG were detected in 70% of cases. These antibodies were absent in the patients with macular ruptures of the retina. In none of the patients were these antibodies detected in the blood serum. The levels of circulating immune complexes were normal in the patients PVCRD and increased in those with macular ruptures of the retina. These data permit a hypothesis on the development of local autoimmune reactions in PVCRD patients in response to the appearance of AG of the injured tissues.

  16. Transducin duplicates in the zebrafish retina and pineal complex: differential specialisation after the teleost tetraploidisation.

    Directory of Open Access Journals (Sweden)

    David Lagman

    Full Text Available Gene duplications provide raw materials that can be selected for functional adaptations by evolutionary mechanisms. We describe here the results of 350 million years of evolution of three functionally related gene families: the alpha, beta and gamma subunits of transducins, the G protein involved in vision. Early vertebrate tetraploidisations resulted in separate transducin heterotrimers: gnat1/gnb1/gngt1 for rods, and gnat2/gnb3/gngt2 for cones. The teleost-specific tetraploidisation generated additional duplicates for gnb1, gnb3 and gngt2. We report here that the duplicates have undergone several types of subfunctionalisation or neofunctionalisation in the zebrafish. We have found that gnb1a and gnb1b are co-expressed at different levels in rods; gnb3a and gnb3b have undergone compartmentalisation restricting gnb3b to the dorsal and medial retina, however, gnb3a expression was detected only at very low levels in both larvae and adult retina; gngt2b expression is restricted to the dorsal and medial retina, whereas gngt2a is expressed ventrally. This dorsoventral distinction could be an adaptation to protect the lower part of the retina from intense light damage. The ontogenetic analysis shows earlier onset of expression in the pineal complex than in the retina, in accordance with its earlier maturation. Additionally, gnb1a but not gnb1b is expressed in the pineal complex, and gnb3b and gngt2b are transiently expressed in the pineal during ontogeny, thus showing partial temporal subfunctionalisation. These retina-pineal distinctions presumably reflect their distinct functional roles in vision and circadian rhythmicity. In summary, this study describes several functional differences between transducin gene duplicates resulting from the teleost-specific tetraploidisation.

  17. Transducin duplicates in the zebrafish retina and pineal complex: differential specialisation after the teleost tetraploidisation.

    Science.gov (United States)

    Lagman, David; Callado-Pérez, Amalia; Franzén, Ilkin E; Larhammar, Dan; Abalo, Xesús M

    2015-01-01

    Gene duplications provide raw materials that can be selected for functional adaptations by evolutionary mechanisms. We describe here the results of 350 million years of evolution of three functionally related gene families: the alpha, beta and gamma subunits of transducins, the G protein involved in vision. Early vertebrate tetraploidisations resulted in separate transducin heterotrimers: gnat1/gnb1/gngt1 for rods, and gnat2/gnb3/gngt2 for cones. The teleost-specific tetraploidisation generated additional duplicates for gnb1, gnb3 and gngt2. We report here that the duplicates have undergone several types of subfunctionalisation or neofunctionalisation in the zebrafish. We have found that gnb1a and gnb1b are co-expressed at different levels in rods; gnb3a and gnb3b have undergone compartmentalisation restricting gnb3b to the dorsal and medial retina, however, gnb3a expression was detected only at very low levels in both larvae and adult retina; gngt2b expression is restricted to the dorsal and medial retina, whereas gngt2a is expressed ventrally. This dorsoventral distinction could be an adaptation to protect the lower part of the retina from intense light damage. The ontogenetic analysis shows earlier onset of expression in the pineal complex than in the retina, in accordance with its earlier maturation. Additionally, gnb1a but not gnb1b is expressed in the pineal complex, and gnb3b and gngt2b are transiently expressed in the pineal during ontogeny, thus showing partial temporal subfunctionalisation. These retina-pineal distinctions presumably reflect their distinct functional roles in vision and circadian rhythmicity. In summary, this study describes several functional differences between transducin gene duplicates resulting from the teleost-specific tetraploidisation.

  18. Dynamic coupling of pattern formation and morphogenesis in the developing vertebrate retina.

    Directory of Open Access Journals (Sweden)

    Alexander Picker

    2009-10-01

    Full Text Available During embryonic development, pattern formation must be tightly synchronized with tissue morphogenesis to coordinate the establishment of the spatial identities of cells with their movements. In the vertebrate retina, patterning along the dorsal-ventral and nasal-temporal (anterior-posterior axes is required for correct spatial representation in the retinotectal map. However, it is unknown how specification of axial cell positions in the retina occurs during the complex process of early eye morphogenesis. Studying zebrafish embryos, we show that morphogenetic tissue rearrangements during eye evagination result in progenitor cells in the nasal half of the retina primordium being brought into proximity to the sources of three fibroblast growth factors, Fgf8/3/24, outside the eye. Triple-mutant analysis shows that this combined Fgf signal fully controls nasal retina identity by regulating the nasal transcription factor Foxg1. Surprisingly, nasal-temporal axis specification occurs very early along the dorsal-ventral axis of the evaginating eye. By in vivo imaging GFP-tagged retinal progenitor cells, we find that subsequent eye morphogenesis requires gradual tissue compaction in the nasal half and directed cell movements into the temporal half of the retina. Balancing these processes drives the progressive alignment of the nasal-temporal retina axis with the anterior-posterior body axis and is controlled by a feed-forward effect of Fgf signaling on Foxg1-mediated cell cohesion. Thus, the mechanistic coupling and dynamic synchronization of tissue patterning with morphogenetic cell behavior through Fgf signaling leads to the graded allocation of cell positional identity in the eye, underlying retinotectal map formation.

  19. Pre-exposure to low-power diode laser irradiation promotes cytoprotection in the rat retina.

    Science.gov (United States)

    Sun, Yue; Zhang, Shisheng; Liao, Huaping; Wang, Jing; Wang, Ling

    2015-01-01

    The aim of this study was to investigate whether pre-exposure to low-power laser irradiation can provoke an effect on cellular protection in the rat retina. The right eyes of 40 rats were exposed to a 3-mm diode laser beam for 1 min in different light intensities and different experimental sets: group A low power of 60 mW (34.27 J/cm(2) on the retina in consideration of the energy losses along the optical pathway) prior to high power of 80 mW (44.88 J/cm(2) on the retina in consideration of the energy losses along the optical pathway), group B high power, group C low power, group D (the left eyes from the counterpart of group A) and group E (untreated rat eyes) as controls. Morphological retinal change retinas were assessed using light microscopy and/or transmission electron microscopy. Heat shock protein (Hsp) 70 and cleaved caspase 3 protein expression were analyzed by immunohistochemical staining and Western blot. Cellular injury was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. Hsp 70 expression in the inner plexiform layer and the outer plexiform layer in group A were 73.09 ± 6.49 and 78.03 ± 3.05%, respectively, which was significantly higher (P retina) power laser irradiation stimulates a hyperexpression of Hsp70 together with a hypoexpression of cleaved caspase 3 in rat retina, which may suggest a cellular protective effect.

  20. Immunolocalisation pattern of complex I-V in ageing human retina: Correlation with mitochondrial ultrastructure.

    Science.gov (United States)

    Nag, Tapas Chandra; Wadhwa, Shashi

    2016-11-01

    Earlier studies reported accumulation of mitochondrial DNA mutations in ageing and age-related macular degeneration. To know about the mitochondrial status with age, we examined immunoreactivity (IR) to markers of mitochondria (anti-mitochondrial antibody and voltage-dependent anion channel-1) and complex I-V (that mediate oxidative phosphorylation, OXPHOS) in donor human retinas (age: 19-94years; N=26; right eyes). In all samples, at all ages, IR to anti-mitochondrial antibody and voltage-dependent anion channel-1 was prominent in photoreceptor cells. Between second and seventh decade of life, strong IR to complex I-V was present in photoreceptors over macular to peripheral retina. With progressive ageing, the photoreceptors showed a decrease in complex I-IR (subunit NDUFB4) at eighth decade, and a weak or absence of IR in 10 retinas between ninth and tenth decade. Patchy IR to complex III and complex IV was detected at different ages. IR to ND1 (complex I) and complex II and V remained unaltered with ageing. Nitrosative stress (evaluated by IR to a nitro-tyrosine antibody) was found in photoreceptors. Superoxide dismutase-2 was found upregulated in photoreceptors with ageing. Mitochondrial ultrastructure was examined in two young retinas with intact complex IR and six aged retinas whose counterparts showed weak to absence of IR. Observations revealed irregular, photoreceptor inner segment mitochondria in aged maculae and mid-peripheral retina between eighth and ninth decade; many cones possessed autophagosomes with damaged mitochondria, indicating age-related alterations. A trend in age-dependent reduction of complex I-IR was evident in aged photoreceptors, whereas patchy complex IV-IR (subunits I and II) was age-independent, suggesting that the former is prone to damage with ageing perhaps due to oxidative stress. These changes in OXPHOS system may influence the energy budget of human photoreceptors, affecting their viability.

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

    Directory of Open Access Journals (Sweden)

    Joseph Bouskila

    Full Text Available Cannabinoids exert their actions mainly through two receptors, the cannabinoid CB1 receptor (CB1R and cannabinoid CB2 receptor (CB2R. In recent years, the G-protein coupled receptor 55 (GPR55 was suggested as a cannabinoid receptor based on its activation by anandamide and tetrahydrocannabinol. 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 components (Müller cells. The aim of this study was to determine the expression pattern of GPR55 in the monkey retina by using confocal microscopy. Our results show that GPR55 is strictly localized in the photoreceptor layer of the extrafoveal portion of the retina. Co-immunolabeling of GPR55 with rhodopsin, the photosensitive pigment in rods, revealed a clear overlap of expression throughout the rod structure with most prominent staining in the inner segments. Additionally, double-label of GPR55 with calbindin, a specific marker for cone photoreceptors in the primate retina, allowed us to exclude expression of GPR55 in cones. The labeling of GPR55 in rods was further assessed with a 3D visualization in the XZ and YZ planes thus confirming its exclusive expression in rods. These results provide data on the distribution of GPR55 in the monkey retina, different than CB1R and CB2R. The presence of GPR55 in rods suggests a function of this receptor in scotopic vision that needs to be demonstrated.

  2. 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

  3. Pharmacokinetic study of mangiferin in rat plasma and retina using high-performance liquid chromatography

    Science.gov (United States)

    Hou, Yunlong; Fan, Shengjun; Gu, Yuanqin; Yu, Xuhui; Li, Baoxin

    2010-01-01

    Purpose Although the naturally occurring antioxidant mangiferin has been widely used, it is not yet known whether it can cross the blood-retina barrier (BRB) and enter the eye. The purpose of this experiment was to investigate the ability of mangiferin to pass the blood-retina barrier. Methods Sprague–Dawley rats were used for biologic fluid sampling after intravenous administration of mangiferin at doses of 10, 25, and 50 mg/kg. Blood and retina samples were collected at different time points post-dose. High-performance liquid chromatography (HPLC) separation was conducted on a COSMOSIL 5C18—MS—II column (4.6 mm×250 mm, 5 μm) with a flow rate of 1.0 ml/min using a mobile phase comprised of methanol −2% glacial acetic acid (40:60 v:v). Results The HPLC method has proven suitable to determine the presence of mangiferin in the eye. The plasma concentration of mangiferin was dose dependent. Pharmacokinetic parameters of mangiferin in plasma after intravenous administration were fitted to the two-compartment model with the first-order elimination and first-order transfer between central and peripheral compartments. The concentration of mangiferin in the retina goes with that in the blood. Mangiferin concentrations in the retina reached 5.69±1.48 μg/ml 0.5 h after intravenous administration (50 mg/kg) and then dropped gradually to 0.30±0.02 μg/ml 5.0 h later. The eye–to-plasma concentration ratio was 2.80%. Conclusions Mangiferin can pass the blood-retina barrier after a single intravenous administration and may be a potential natural antioxidant in treating eye diseases. PMID:20806037

  4. Gene expression and protein distribution of orexins and orexin receptors in rat retina.

    Science.gov (United States)

    Liu, F; Xu, G Z; Wang, L; Jiang, S X; Yang, X L; Zhong, Y M

    2011-08-25

    Orexins, composed of orexin A and orexin B, are identified as endogenous ligands of two orphan G-protein-coupled receptors: orexin 1 and orexin 2 receptors (OX1R and OX2R). Orexins are implicated in regulating wake/sleep states, feeding behaviors, etc. Using reverse transcription-polymerase chain reactive (RT-PCR) analysis and immunofluorescence double labeling, we investigated the distributions of orexin A, orexin B, OX1R and OX2R in rat retina. RT-PCR analysis revealed the presence of mRNAs of prepro-orexin, OX1R and OX2R in rat retina. Immunostaining for orexin A and orexin B was observed in many cells in the inner nuclear layer and the ganglion cell layer. In the outer retina, horizontal cells, labeled by calbindin, and bipolar cells, labeled by homeobox protein Chx10, were orexin A- and orexin B-positive. In the inner retina, two orexins were both found in GABAergic amacrine cells (ACs), including dopaminergic and cholinergic ones, stained by tyrosine hydroxylase and choline acetyltransferase respectively. Glycinergic ACs, including AII ACs, also expressed orexins. Weak to moderate labeling for orexin A and orexin B was diffusely distributed in the inner plexiform layer. Additionally, orexins were expressed in almost all ganglion cells (GCs) retrogradely labeled by cholera toxin B subunit. Specifically, double-labeling experiments demonstrated that melanopsin-positive GCs (intrinsically photosensitive retinal GCs, ipRGCs) were labeled by two orexins. Morever, OX1R immunoreactivity was observed in most of GCs and all dopaminergic ACs, as well as in both outer and inner plexiform layers. In contrast, no obvious OX2R immunostaining was detectable in the rat retina. These results suggest that orexins may modulate the function of neurons, especially in the inner retina. We further hypothesize that the orexin signaling via ipRGCs may be involved in setting the suprachiasmatic nucleus (SCN) circadian clock.

  5. Design and realization of retina-like three-dimensional imaging based on a MOEMS mirror

    Science.gov (United States)

    Cao, Jie; Hao, Qun; Xia, Wenze; Peng, Yuxin; Cheng, Yang; Mu, Jiaxing; Wang, Peng

    2016-07-01

    To balance conflicts for high-resolution, large-field-of-view and real-time imaging, a retina-like imaging method based on time-of flight (TOF) is proposed. Mathematical models of 3D imaging based on MOEMS are developed. Based on this method, we perform simulations of retina-like scanning properties, including compression of redundant information and rotation and scaling invariance. To validate the theory, we develop a prototype and conduct relevant experiments. The preliminary results agree well with the simulations.

  6. High resolution mosaic image of capillaries in human retina by adaptive optics

    Institute of Scientific and Technical Information of China (English)

    Ning Ling; Yudong Zhang; Xuejun Rao; Cheng Wang; Yiyun Hu; Wenhan Jiang

    2005-01-01

    Adaptive optics (AO) has been proved as a powerful means for high resolution imaging of human retina.Because of the pixel number of charge-coupled device (CCD) camera, the field of view is limited to 1°.In order to have image of capillaries around vivo human fovea, we use mosaic method to obtain high resolution image in area of 6°× 6°. Detailed structures of capillaries around fovea with resolution of 2.3μm are clearly shown. Comparison shows that this method has a much higher resolution than current clinic retina imaging methods.

  7. Pharmacological Protection of the Retina against Damaging Laser Exposures: A Feasibility Study

    Science.gov (United States)

    1988-09-01

    because of its gelatinous nature in the rabbit, it could be gently removed without tearing the retina. Four or five radial cuts, each about 1-2 mm...Component mq/L uM L-glutamine 73 500 taurine 0.75 6 choline Cl 0.6 4.3 myo-inositol 27 150 Na pyruvate 22 200 ascorbate 18 100 glucose 1800 10,000...32,36,37). This difference could be due to a protective effect conferred by melanosomes in the retina, since the other natural anti-oxidant

  8. Rod Photoreceptors Express GPR55 in the Adult Vervet Monkey Retina

    OpenAIRE

    Joseph Bouskila; Pasha Javadi; Christian Casanova; Maurice Ptito; Jean-François Bouchard

    2013-01-01

    Cannabinoids exert their actions mainly through two receptors, the cannabinoid CB1 receptor (CB1R) and cannabinoid CB2 receptor (CB2R). In recent years, the G-protein coupled receptor 55 (GPR55) was suggested as a cannabinoid receptor based on its activation by anandamide and tetrahydrocannabinol. 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 n...

  9. Desprendimiento de retina regmatógeno. Actuación de Enfermería

    OpenAIRE

    Domínguez Manzano, María

    2016-01-01

    El objetivo principal de este trabajo es, la realización y presentación con la recopilación e información actualizada en el desprendimiento de retina regmatógeno, para preparar los conocimientos teóricos y prácticos necesarios y poder realizar el trabajo diario con la mayor calidad posible. Los principales objetivos secundarios planteados son: 1. Conocer en qué consiste la patología del desprendimiento de retina y definir la etiología, patogenia, evolución, tratamiento y posibles compli...

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

    OpenAIRE

    Bouskila, Joseph; Javadi, Pasha; Elkrief, Laurent; Casanova, Christian; Bouchard, Jean-François; Ptito, Maurice

    2016-01-01

    The endocannabinoid (eCB) system is widely expressed in various parts of the central nervous system, including the retina. The localization of the key eCB receptors, particularly CB1R and CB2R, has been recently reported in rodent and primate retinas with striking interspecies differences. Little 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 ...

  11. Degenerações periféricas da retina do olho míope X LASIK

    Directory of Open Access Journals (Sweden)

    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.

  12. Comparative analysis of the expression of neural stem cell-associated genes during neocortex and retina development in human.

    Science.gov (United States)

    Verdiev, B I; Milyushina, L A; Podgornyi, O V; Poltavtseva, R A; Zinov'eva, R D; Sukhikh, G T; Aleksandrova, M A

    2013-02-01

    We compared the expression of Sox2, Oct4, Nanog, Pax6, Prox1 genes associated with plasticity of neural stem and progenitor cells during human neocortex and retina development and in cell cultures. At the analyzed stages of neurogenesis, Pax6 gene is expressed in the neocortex and retina at constant levels, the expression is by one order of magnitude higher in the retina. The dynamics of Sox2 and Pax6 expression in the neocortex was similar. The expression of Oct4 and Nanog genes during neurogenesis in the neocortex and human fetal retina reflects the existence of a high-plasticity cell pool. The dynamics of βIII-tubulin expression indicates that the retina develops more rapidly than the neocortex. Our experiments showed that genetically determined cell potencies typical of native cells are realized in primary cultures without specific stimulation.

  13. Regulation of Stem Cell Properties of Müller Glia by JAK/STAT and MAPK Signaling in the Mammalian Retina

    OpenAIRE

    Beach, Krista M.; Jianbo Wang; Otteson, Deborah C.

    2017-01-01

    In humans and other mammals, the neural retina does not spontaneously regenerate, and damage to the retina that kills retinal neurons results in permanent blindness. In contrast to embryonic stem cells, induced pluripotent stem cells, and embryonic/fetal retinal stem cells, Müller glia offer an intrinsic cellular source for regenerative strategies in the retina. Müller glia are radial glial cells within the retina that maintain retinal homeostasis, buffer ion flux associated with phototransdu...

  14. 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

  15. Early development of GABAergic cells of the retina in sharks: an immunohistochemical study with GABA and GAD antibodies.

    Science.gov (United States)

    Ferreiro-Galve, Susana; Candal, Eva; Carrera, Iván; Anadón, Ramón; Rodríguez-Moldes, Isabel

    2008-09-01

    We studied the ontogeny and organization of GABAergic cells in the retina of two elasmobranches, the lesser-spotted dogfish (Scyliorhinus canicula) and the brown shyshark (Haploblepharus fuscus) by using immunohistochemistry for gamma-aminobutyric acid (GABA) and glutamic acid decarboxylase (GAD). Both antibodies revealed the same pattern of immunoreactivity and both species showed similar organization of GABAergic cells. GABAergic cells were first detected in neural retina of embryos at stage 26, which showed a neuroepithelial appearance without any layering. In stages 27-29 the retina showed similar organization but the number of neuroblastic GABAergic cells increased. When layering became apparent in the central retina (stage-30 embryos), GABAergic cells mainly appeared organized in the outer and inner retina, and GABAergic processes and fibres were seen in the primordial inner plexiform layer (IPL), optic fibre layer and optic nerve stalk. In stage-32 embryos, layering was completed in the central retina, where immunoreactivity appeared in perikarya of the horizontal cell layer, inner nuclear layer and ganglion cell layer, and in numerous processes coursing in the IPL, optic fibre layer and optic nerve. From stage 32 to hatching (stage 34), the layered retina extends from centre-to-periphery, recapitulating that observed in the central retina at earlier stages. In adults, GABA/GAD immunoreactivity disappears from the horizontal cell layer except in the marginal retina. Our results indicate that the source of GABA in the shark retina can be explained by its synthesis by GAD. Such synthesis precedes layering and synaptogenesis, thus supporting a developmental role for GABA in addition to act as neurotransmitter and neuromodulator.

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

    Directory of Open Access Journals (Sweden)

    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

  17. 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 resu

  18. Species-specific wiring for direction selectivity in the mammalian retina.

    Science.gov (United States)

    Ding, Huayu; Smith, Robert G; Poleg-Polsky, Alon; Diamond, Jeffrey S; Briggman, Kevin L

    2016-07-07

    Directionally tuned signalling in starburst amacrine cell (SAC) dendrites lies at the heart of the circuit that detects the direction of moving stimuli in the mammalian retina. The relative contributions of intrinsic cellular properties and network connectivity to SAC direction selectivity remain unclear. Here we present a detailed connectomic reconstruction of SAC circuitry in mouse retina and describe two previously unknown features of synapse distributions along SAC dendrites: input and output synapses are segregated, with inputs restricted to proximal dendrites; and the distribution of inhibitory inputs is fundamentally different from that observed in rabbit retina. An anatomically constrained SAC network model suggests that SAC–SAC wiring differences between mouse and rabbit retina underlie distinct contributions of synaptic inhibition to velocity and contrast tuning and receptive field structure. In particular, the model indicates that mouse connectivity enables SACs to encode lower linear velocities that account for smaller eye diameter, thereby conserving angular velocity tuning. These predictions are confirmed with calcium imaging of mouse SAC dendrites responding to directional stimuli.

  19. Investigation of alterations in multifractality in optical coherence tomographic images of in vivo human retina

    Science.gov (United States)

    Das, Nandan Kumar; Mukhopadhyay, Sabyasachi; Ghosh, Nirmalya; Chhablani, Jay; Richhariya, Ashutosh; Divakar Rao, Kompalli; Sahoo, Naba Kishore

    2016-09-01

    Optical coherence tomography (OCT) enables us to monitor alterations in the thickness of the retinal layer as disease progresses in the human retina. However, subtle morphological changes in the retinal layers due to early disease progression often may not lead to detectable alterations in the thickness. OCT images encode depth-dependent backscattered intensity distribution arising due to the depth distributions of the refractive index from tissue microstructures. Here, such depth-resolved refractive index variations of different retinal layers were analyzed using multifractal detrended fluctuation analysis, a special class of multiresolution analysis tools. The analysis extracted and quantified microstructural multifractal information encoded in normal as well as diseased human retinal OCT images acquired in vivo. Interestingly, different layers of the retina exhibited different degrees of multifractality in a particular retina, and the individual layers displayed consistent multifractal trends in healthy retinas of different human subjects. In the retinal layers of diabetic macular edema (DME) subjects, the change in multifractality manifested prominently near the boundary of the DME as compared to the normal retinal layers. The demonstrated ability to quantify depth-resolved information on multifractality encoded in OCT images appears promising for the early diagnosis of diseases of the human eye, which may also prove useful for detecting other types of tissue abnormalities from OCT images.

  20. Expression of ciliary neurotrophic factor after induction of ocular hypertension in the retina of rats

    Institute of Scientific and Technical Information of China (English)

    WU Qiang; ZHANG Min; SONG Bei-wen; LU Bin; HU Ping

    2007-01-01

    Background Glaucoma is mainly characterized by the loss of retinal ganglion cells. Ciliary neurotrophic factor (CNTF) is believed to stimulate the regeneration of axons of retinal ganglion cells. The objective of our study was to detect the expression of CNTF in the retina of a rat glaucoma model with increased intraocular pressure (lOP).Methods The rat glaucoma model was set up by electrocoagulating at least three episcleral and limbal veins. The location and the expression level of CNTF were detected at 1, 3, 7, 14, and 28 days post-surgery by immunohistochemistry, semiquantitative reverse-transcription polymerase chain reaction (RT-PCR), and Western blot analysis.Results The rat glaucoma model with chronic, moderately elevated lOP was successfully produced. A minimum expression of CNTF was found in the ganglion cell layer of the retinas of the control group, and temporally increased expression and intensity of CNTF were found in the experimental retinas.Conclusion The expression of endogenous CNTF in the rat retina was found altered after the induction of ocular hypertension.

  1. Retinal Physiology: Non-Bipolar-Cell Excitatory Drive in the Inner Retina.

    Science.gov (United States)

    Baden, Tom; Euler, Thomas

    2016-08-01

    The long-held view that bipolar cells provide the exclusive excitatory drive to the mammalian inner retina has been challenged: new studies indicate that, instead, at least two cells that lack the dendrites characteristic for bipolar cells, and therefore resemble amacrine cells, excite inner retinal circuits using glutamate.

  2. Melatonin reprogrammes proteomic profile in light-exposed retina in vivo

    Science.gov (United States)

    Zhang, Ruonan; Hrushesky, William J.M.; Wood, Patricia A.; Lee, Sung Haeng; Hunt, Richard C.; Jahng, Wan Jin

    2017-01-01

    Melatonin, a small organic molecule synthesized by the pineal gland and the retina, has a variety of physiologic functions such as circadian clock pacemaker and antioxidant. Retinal melatonin is down-regulated by light and is barely detectable during the day. The absence of melatonin in the retina during prolonged light exposure may contribute to light-induced retinal degeneration. We sought to investigate the impact of melatonin in the light-exposed retina using proteomic approaches. We exposed mice to either light (250–300 lux) for 12 h followed by 12 h of darkness or the same intensity of continuous light for 7 days. In half of the animals exposed to continuous light, melatonin was injected each night. Proteomic analysis of the retina from these three groups of animals showed that five proteins prominently up-regulated by constant light were down-regulated by melatonin treatment. These five proteins were identified as vimentin, serine/threonine-protein phosphatase 2A, Rab GDP dissociation inhibitor alpha, guanine nucleotide-binding protein Go alpha, and retinaldehyde-binding protein. These five proteins are known to be involved in several cellular processes that may contribute to light-induced retinal degeneration. Identification of melatonin target proteins in our study provides a basis for future studies on melatonin’s potential in preventing or treating light-induced retinal degeneration. PMID:20434483

  3. [Functional alterations in the retina following a 10 Gy gamma irradiation localized in the eye].

    Science.gov (United States)

    Bagot, J D; Courant, D; Court, L

    1980-11-17

    A single-eye irradiation of 10 Gy (0.8 Gy. min-1) induces impairments of the electrical responses of the rabbit retina in dark adaptation. These are associated with reversible alteration of the photoreceptors and the preganglionic neurons and a disturbance of all the mechanisms of adaptation. Possible relationships between these functional alterations and the effects of irradiation are discussed.

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

    Institute of Scientific and Technical Information of China (English)

    Jiang Bao-Guang; Cao Zhao-Liang; Mu Quan-Quan; Hu Li-Fa; 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 A 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 diffraction limit resolution. The carbon granule on the white paper which has a size of 4.7μm is seen clearly. The size of the retina cell is between 4 and 10 μm. So this system has an ability to image the human eye's retina.

  5. Celsr3 is required for normal development of GABA circuits in the inner retina.

    Directory of Open Access Journals (Sweden)

    Alaron Lewis

    2011-08-01

    Full Text Available The identity of the specific molecules required for the process of retinal circuitry formation is largely unknown. Here we report a newly identified zebrafish mutant in which the absence of the atypical cadherin, Celsr3, leads to a specific defect in the development of GABAergic signaling in the inner retina. This mutant lacks an optokinetic response (OKR, the ability to visually track rotating illuminated stripes, and develops a super-normal b-wave in the electroretinogram (ERG. We find that celsr3 mRNA is abundant in the amacrine and ganglion cells of the retina, however its loss does not affect synaptic lamination within the inner plexiform layer (IPL or amacrine cell number. We localize the ERG defect pharmacologically to a late-stage disruption in GABAergic modulation of ON-bipolar cell pathway and find that the DNQX-sensitive fast b1 component of the ERG is specifically affected in this mutant. Consistently, we find an increase in GABA receptors on mutant ON-bipolar terminals, providing a direct link between the observed physiological changes and alterations in GABA signaling components. Finally, using blastula transplantation, we show that the lack of an OKR is due, at least partially, to Celsr3-mediated defects within the brain. These findings support the previously postulated inner retina origin for the b1 component and reveal a new role for Celsr3 in the normal development of ON visual pathway circuitry in the inner retina.

  6. 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.

  7. Lgr5⁺ amacrine cells possess regenerative potential in the retina of adult mice.

    Science.gov (United States)

    Chen, Mengfei; Tian, Shenghe; Glasgow, Nathan G; Gibson, Gregory; Yang, Xiaoling; Shiber, Christen E; Funderburgh, James; Watkins, Simon; Johnson, Jon W; Schuman, Joel S; Liu, Hongjun

    2015-08-01

    Current knowledge indicates that the adult mammalian retina lacks regenerative capacity. Here, we show that the adult stem cell marker, leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5), is expressed in the retina of adult mice. Lgr5(+) cells are generated at late stages of retinal development and exhibit properties of differentiated amacrine interneurons (amacrine cells). Nevertheless, Lgr5(+) amacrine cells contribute to regeneration of new retinal cells in the adult stage. The generation of new retinal cells, including retinal neurons and Müller glia from Lgr5(+) amacrine cells, begins in early adulthood and continues as the animal ages. Together, these findings suggest that the mammalian retina is not devoid of regeneration as previously thought. It is rather dynamic, and Lgr5(+) amacrine cells function as an endogenous regenerative source. The identification of such cells in the mammalian retina may provide new insights into neuronal regeneration and point to therapeutic opportunities for age-related retinal degenerative diseases.

  8. BMP signaling mediates stem/progenitor cell-induced retina regeneration.

    Science.gov (United States)

    Haynes, Tracy; Gutierrez, Christian; Aycinena, Juan-Carlos; Tsonis, Panagiotis A; Del Rio-Tsonis, Katia

    2007-12-18

    We identified a mechanism whereby retina regeneration in the embryonic chick can be induced by the contribution of stem/progenitor cells. We show that bone morphogenetic protein (BMP) signaling is sufficient and necessary to induce retina regeneration and that its action can be divided into two phases. By 3 days after postretinectomy (d PR), the BMP pathway directs proliferation and regeneration through the activation of Smad (canonical BMP pathway) and the up-regulation of FGF signaling by the MAPK pathway. By 7d PR, it induces apoptosis by activating p38 (a noncanonical BMP pathway) and down-regulating FGF signaling (by both MAPK and AKT pathways). Apoptosis at this later stage can be prevented, and BMP-induced regeneration can be further induced by inhibition of p38. These results unravel a mechanism for stem/progenitor cell-mediated retina regeneration, where BMP activation establishes a cross-talk with the FGF pathway and selectively activates the canonical and noncanonical BMP pathways. Retina stem/progenitor cells exist in other species, including humans. Thus, our findings provide insights on how retinal stem cells can be activated for possible regenerative therapies.

  9. Study and retina allotransplantation of porcine ciliary epithelium (CE)-derived cells

    NARCIS (Netherlands)

    Cogliati, Tiziana Paola

    2012-01-01

    This thesis reports the isolation, characterization and allotransplantation in porcine retina of ciliary epithelium (CE)-derived cells, also known as retinal stem cells (RSCs). The self-renewal capacity and differentiation potential of these cells in vitro and in vivo makes them candidate donors in

  10. Recruitment of stem cells into the injured retina after laser injury.

    Science.gov (United States)

    Singh, Tajinder; Prabhakar, Sudesh; Gupta, Amod; Anand, Akshay

    2012-02-10

    Retinal degeneration is a devastating complication of diabetes and other disorders. Stem cell therapy for retinal degeneration has shown encouraging results but functional regeneration has not been yet achieved. Our study was undertaken to evaluate the localization of stem cells delivered to the retina by intravenous versus intravitreal infusion, because stem cell localization is a key factor in ultimate in vivo function. We used lineage-negative bone marrow-derived stem cells in a model wherein retina of mice was induced by precise and reproducible laser injury. Lin(-ve) bone marrow cells (BMCs) were labeled with a tracking dye and their homing capacity was analyzed at time points after infusion. We found that Lin(-ve) BMCs get incorporated into laser-injured retina when transplanted through either the intravitreal or intravenous route. The intravenous route resulted in optimal localization of donor cells at the site of injury. These cells incorporated into injured retina in a dose-dependent manner. The data presented in this study reflect the importance of dose and route for stem cell-based treatment designed to result in retinal regeneration.

  11. Using myc genes to search for stem cells in the ciliary margin of the Xenopus retina.

    Science.gov (United States)

    Xue, Xiao Yan; Harris, William A

    2012-04-01

    The ciliary marginal zone (CMZ) of fish and frog retinas contains cells that proliferate throughout postembryonic development as the retina grows with increasing body size, indicating the presence of stem cells in this region. However, neither the location nor the molecular identity of retinal stem cells has been identified. Here, we show in Xenopus that c-myc and n-myc are sequentially expressed both during development and in the post-embryonic retina. The c-myc+/n-myc- cells near the extreme periphery of the CMZ cycle more slowly and preferentially retain DNA label compared to their more central cmyc+/n-myc+ neighbors which cycle rapidly and preferentially dilute DNA label. During retinal development c-myc is functionally required earlier than n-myc, and n-myc expression depends on earlier c-myc expression. The expression of c-myc but not n-myc in the CMZ depends on growth factor signaling. Our results suggest that c-myc+/n-myc- cells in the far peripheral CMZ are candidates for a niche-dependent population of retinal stem cells that give rise to more centrally located and rapidly dividing n-myc+ progenitors of more limited proliferative potential. Analysis of homologues of these genes in the zebrafish CMZ suggests that the transition from c-myc to n-myc expression might be conserved in other lower vertebrates whose retinas growth throughout life.

  12. Age-related decrease in rod bipolar cell density of the human retina: an immunohistochemical study

    Indian Academy of Sciences (India)

    P Aggarwal; T C Nag; S Wadhwa

    2007-03-01

    During normal ageing, the rods (and other neurones) undergo a significant decrease in density in the human retina from the fourth decade of life onward. Since the rods synapse with the rod bipolar cells in the outer plexiform layer, a decline in rod density (mainly due to death) may ultimately cause an associated decline of the neurones which, like the rod bipolar cells, are connected to them. The rod bipolar cells are selectively stained with antibodies to protein kinase C-. This study examined if rod bipolar cell density changes with ageing of the retina, utilizing donor human eyes (age: 6–91 years). The retinas were fixed and their temporal parts from the macula to the mid-periphery sectioned and processed for protein kinase C- immunohistochemistry. The density of the immunopositive rod bipolar cells was estimated in the mid-peripheral retina (eccentricity: 3–5 mm) along the horizontal temporal axis. The results show that while there is little change in the density of the rod bipolar cells from 6 to 35 years (2.2%), the decline during the period from 35 to 62 years is about 21% and between seventh and tenth decades, it is approximately 27%.

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

    NARCIS (Netherlands)

    Cornelissen, Frans W.; Brenner, Eli

    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 th

  14. The Wilms' tumor gene Wt1 is required for normal development of the retina.

    Science.gov (United States)

    Wagner, Kay-Dietrich; Wagner, Nicole; Vidal, Valerie P I; Schley, Gunnar; Wilhelm, Dagmar; Schedl, Andreas; Englert, Christoph; Scholz, Holger

    2002-03-15

    The Wilms' tumor gene Wt1 is known for its important functions during genitourinary and mesothelial formation. Here we show that Wt1 is necessary for neuronal development in the vertebrate retina. Mouse embryos with targeted disruption of Wt1 exhibit remarkably thinner retinas than age-matched wild-type animals. A large fraction of retinal ganglion cells is lost by apoptosis, and the growth of optic nerve fibers is severely disturbed. Strikingly, expression of the class IV POU-domain transcription factor Pou4f2 (formerly Brn-3b), which is critical for the survival of most retinal ganglion cells, is lost in Wt1(-/-) retinas. Forced expression of Wt1 in cultured cells causes an up-regulation of Pou4f2 mRNA. Moreover, the Wt1(-KTS) splice variant can activate a reporter construct carrying 5'-regulatory sequences of the human POU4F2. The lack of Pou4f2 and the ocular defects in Wt1(-/-) embryos are rescued by transgenic expression of a 280 kb yeast artificial chromosome carrying the human WT1 gene. Taken together, our findings demonstrate a continuous requirement for Wt1 in normal retina formation with a critical role in Pou4f2-dependent ganglion cell differentiation.

  15. A preparation for studying electrical stimulation of the retina in vivo in rat.

    Science.gov (United States)

    Baig-Silva, M S; Hathcock, C D; Hetling, J R

    2005-03-01

    A remaining challenge to the development of electronic prostheses for vision is improving the effectiveness of retinal stimulation. Electrode design and stimulus parameters need to be optimized such that the neural output from the retina conveys information to the mind's eye that aids the patient in interpreting his or her environment. This optimization will require a detailed understanding of the response of the retina to electrical stimulation. The identity and response characteristics of the cellular targets of stimulation need to be defined and evaluated. Described here is an in vivo preparation for studying electrical stimulation of the retina in rat at the cellular level. The use of rat makes available a number of well-described models of retinal disease that motivate prosthesis development. Artificial stimulation can be investigated by adapting techniques traditionally employed to study the response of the retina to photic stimuli, such as recording at the cornea, single-cell recording, and pharmacological dissection of the response. Pilot studies include amplitude-intensity response data for subretinal and transretinal stimulation paradigms recorded in wild-type rats and a transgenic rat model of autosomal dominant retinitis pigmentosa. The ability to record single-unit ganglion cell activity in vivo is also demonstrated.

  16. Foveal reflection analyzer : on the spectral and directional reflectance of the retina

    NARCIS (Netherlands)

    Zagers, Niels Petrus Antonius

    2004-01-01

    The first part of this thesis was on the development of a new instrument for measurement of light reflected from the retina in a living human eye. The key element is an imaging spectrograph, with its slit placed conjugate to the pupil of the eye. The instrument measures both the spectral and the dir

  17. Expression of neuropeptides and their receptors in the developing retina of mammals

    OpenAIRE

    bagnoli, P; M. Dal Monte; Casini, G.

    2003-01-01

    The present review examines various aspects of the developmental expression of neuropeptides and of their receptors in mammalian retinas, emphasizing their possible roles in retinal maturation. Different peptidergic systems have been investigated with some detail during retinal development, including substance P (SP), somatostatin (SRIF), vasoactive intestinal polypeptide (VIP), pituitary adenylate cyclase-activating polypeptide (PACAP), neuropeptide Y (NPY...

  18. An analog VLSI chip emulating sustained and transient response channels of the vertebrate retina.

    Science.gov (United States)

    Kameda, S; Yagi, T

    2003-01-01

    A silicon retina that emulates the sustained and the transient responses in the vertebrate retina was fabricated. The circuit of the chip consists of two layers of resistive network that have different length constants. The output emulating the sustained response possesses a Laplacian-Gaussian-like receptive field and, therefore, carries out a smoothing and contrast-enhancement on the input images. This receptive field was realized by subtracting voltages distributing over the two resistive networks. The output emulating the transient response was obtained by subtracting consecutive images that were smoothed out by the resistive network and is sensitive to moving objects. The outputs of these two channels can be obtained alternately from the silicon retina in real time, within time delays not exceeding a few tens of milliseconds, with indoor illumination. The outputs of the chip are offset-suppressed analog voltages since the uncontrollable mismatches of transistor characteristics are compensated for with the aid of sample/hold circuits embedded in each pixel circuit. The silicon retina fabricated in the present study can be readily used in current engineering applications, e.g., robot vision.

  19. The Wellcome Prize Lecture. Visual signals in the retina: from photons to synapses.

    Science.gov (United States)

    Lagnado, L

    2000-01-01

    The ability to see the world around us is an immediate and striking example of the abilities of the nervous system, and perhaps for this reason, vision is one of the most intensively studied aspects of brain function (Hubel, 1995). This paper examines some of the earliest steps in vision occurring in the retina (Dowling, 1987; Rodieck, 1998).

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

    Science.gov (United States)

    Bouchard, Jean-François; Casanova, Christian; Cécyre, Bruno; Redmond, William John

    2016-01-01

    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.

  1. 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.

  2. IMMUNOHISTOCHEMICAL DISTRIBUTION OF ERYTHROPOIETIN AND ITS RECEPTOR EXPRESSION IN POSTNATAL RAT RETINA DEVELOPMENT

    Institute of Scientific and Technical Information of China (English)

    ZHONG Yi-sheng; LIU Xiao-hong; HUANG Ping; CHENG Yu

    2008-01-01

    Objective To investigate the distribution of erythropoietin (EPO) and erythropoietin receptor (EPOR) expression in the postnatal rat retina development.Methods Forty-two male Sprague-Dawley rats were divided into 7 groups according to their various postnatal days: postnatal 1 d (D1 group), 3 d (D3 group), 1 week (W1 group), 2 weeks (W2 group), 3 weeks (W3 group), 4 weeks (W4 group) and 8 weeks (W8 group) (n=6). Single eye was randomly chosen from each rat for the study. The retinal sections were stained with hematoxylin and eosin (HE) and used for the retina development observation. Immunohistochemical staining was used to localize EPO and EPOR expressions in retinas of different stages of development, and the expression intensities were determined by an image plus 4 program.Results The retinal inner nuclear layer (INL) and outer nuclear layer (ONL) were mixed together and had not yet fully differentiated in D1 and D3 groups. The INL and ONL formed their own independent regions and the outer plexiform layer (OPL) appeared between two layers in W1 group. With the postnatal retinal development, the inner plexiform layer (IPL), rods and cones layer (RCL), and OPL were gradually widened and stabilized in W2 to W3 groups. EPO/EPOR expressions located prominently in the inner part of the postnatal rat developing retinas. The expression of EPO in GCL and INL gradually increased from D1 to W4, then the expression decreased in W8. Expression of EPOR in GCL gradually increased from D1 to W1, then decreased in W2; and it gradually increased again from W3 to W8. Expression of EPOR in INL gradually increased from D1 to W1, then decreased in W2; and it continued to decrease from W3 to W8. Expression of EPOR in the external segment of RCL gradually increased from D1 to W8. However, expression in the internal segment of RCL gradually decreased from D1 to W3, then no obvious expression was seen in the internal segment of RCL in W4 and W8.Conclusion EPO/EPOR expressions locate

  3. Progesterone receptor membrane component 1 (PGRMC1) expression in murine retina

    Science.gov (United States)

    Shanmugam, Arul K.; Mysona, Barbara A.; Wang, Jing; Zhao, Jing; Tawfik, Amany; Sanders, A.; Markand, Shanu; Zorrilla, Eric; Ganapathy, Vadivel; Bollinger, Kathryn E.; Smith, Sylvia B.

    2015-01-01

    Purpose Sigma receptor 1 (σR1) and 2 (σR2) are thought to be two distinct proteins which share the ability to bind multiple ligands, several of which are common to both receptors. Whether σR1 and σR2 share overlapping biological functions is unknown. Recently, progesterone receptor membrane component 1 (PGRMC1) was shown to contain the putative σR2 binding site. PGRMC1 has not been studied in retina. We hypothesize that biological interactions between σR1 and PGRMC1 will be evidenced by compensatory upregulation of PGRMC1 in σR1−/− mice. Methods Immunofluorescence, RT-PCR, and immunoblotting methods were used to analyze expression of PGRMC1 in wild type mouse retina. Tissues from σR1−/− mice were used to investigate whether a biological interaction exists between σR1 and PGRMC1. Results In the eye, PGRMC1 is expressed in corneal epithelium, lens, ciliary body epithelium, and retina. In retina, PGRMC1 is present in Müller cells and retinal pigment epithelium. This expression pattern is similar, but not identical to σR1. PGRMC1 protein levels in neural retina and eye cup from σR1−/− mice did not differ from wild type mice. Nonocular tissues, lung, heart, and kidney showed similar Pgrmc1 gene expression in wild type and σR1−/− mice. In contrast, liver, brain and intestine showed increased Pgrmc1 gene expression in σR1−/− mice. Conclusion Despite potential biological overlap, deletion of σR1 did not result in a compensatory change in PGRMC1 protein levels in σR1−/− mouse retina. Increased Pgrmc1 gene expression in organs with high lipid content such as liver, brain, and intestine indicate a possible tissue specific interaction between σR1 and PGRMC1. The current studies establish the presence of PGRMC1 in retina and lay the foundation for analysis of its biological function. PMID:26642738

  4. 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.

  5. 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.

  6. Step-by-step instructions for retina recordings with perforated multi electrode arrays.

    Directory of Open Access Journals (Sweden)

    Katja Reinhard

    Full Text Available Multi-electrode arrays are a state-of-the-art tool in electrophysiology, also in retina research. The output cells of the retina, the retinal ganglion cells, form a monolayer in many species and are well accessible due to their proximity to the inner retinal surface. This structure has allowed the use of multi-electrode arrays for high-throughput, parallel recordings of retinal responses to presented visual stimuli, and has led to significant new insights into retinal organization and function. However, using conventional arrays where electrodes are embedded into a glass or ceramic plate can be associated with three main problems: (1 low signal-to-noise ratio due to poor contact between electrodes and tissue, especially in the case of strongly curved retinas from small animals, e.g. rodents; (2 insufficient oxygen and nutrient supply to cells located on the bottom of the recording chamber; and (3 displacement of the tissue during recordings. Perforated multi-electrode arrays (pMEAs have been found to alleviate all three issues in brain slice recordings. Over the last years, we have been using such perforated arrays to study light evoked activity in the retinas of various species including mouse, pig, and human. In this article, we provide detailed step-by-step instructions for the use of perforated MEAs to record visual responses from the retina, including spike recordings from retinal ganglion cells and in vitro electroretinograms (ERG. In addition, we provide in-depth technical and methodological troubleshooting information, and show example recordings of good quality as well as examples for the various problems which might be encountered. While our description is based on the specific equipment we use in our own lab, it may also prove useful when establishing retinal MEA recordings with other equipment.

  7. Synthesis of docosahexaenoic acid from eicosapentaenoic acid in retina neurons protects photoreceptors from oxidative stress.

    Science.gov (United States)

    Simón, María Victoria; Agnolazza, Daniela L; German, Olga Lorena; Garelli, Andrés; Politi, Luis E; Agbaga, Martin-Paul; Anderson, Robert E; Rotstein, Nora P

    2016-03-01

    Oxidative stress is involved in activating photoreceptor death in several retinal degenerations. Docosahexaenoic acid (DHA), the major polyunsaturated fatty acid in the retina, protects cultured retina photoreceptors from apoptosis induced by oxidative stress and promotes photoreceptor differentiation. Here, we investigated whether eicosapentaenoic acid (EPA), a metabolic precursor to DHA, had similar effects and whether retinal neurons could metabolize EPA to DHA. Adding EPA to rat retina neuronal cultures increased opsin expression and protected photoreceptors from apoptosis induced by the oxidants paraquat and hydrogen peroxide (H2 O2 ). Palmitic, oleic, and arachidonic acids had no protective effect, showing the specificity for DHA. We found that EPA supplementation significantly increased DHA percentage in retinal neurons, but not EPA percentage. Photoreceptors and glial cells expressed Δ6 desaturase (FADS2), which introduces the last double bond in DHA biosynthetic pathway. Pre-treatment of neuronal cultures with CP-24879 hydrochloride, a Δ5/Δ6 desaturase inhibitor, prevented EPA-induced increase in DHA percentage and completely blocked EPA protection and its effect on photoreceptor differentiation. These results suggest that EPA promoted photoreceptor differentiation and rescued photoreceptors from oxidative stress-induced apoptosis through its elongation and desaturation to DHA. Our data show, for the first time, that isolated retinal neurons can synthesize DHA in culture. Docosahexaenoic acid (DHA), the major polyunsaturated fatty acid in retina photoreceptors, and its precursor, eicosapentaenoic acid (EPA) have multiple beneficial effects. Here, we show that retina neurons in vitro express the desaturase FADS2 and can synthesize DHA from EPA. Moreover, addition of EPA to these cultures protects photoreceptors from oxidative stress and promotes their differentiation through its metabolization to DHA.

  8. Expression patterns of the retinal development-related genes in the fetal and adult retina

    Institute of Scientific and Technical Information of China (English)

    LI Hui-ming; WANG Feng; QIU Wei; LIU Yan; HUANG Qian

    2007-01-01

    Background Retina is important in converting light into neural signals, but little is known about the regulatory genes essential for the retinal morphological formation, development and functional differentiation. This study aimed to investigate the mRNA expression patterns and cellular or subcellular distribution of 33 differentially expressed genes in the retina belonging to the early and middle-late embryogenesis stages as well as the early adult stage during human development.Methods In situ hybridization and real-time fluorescent quantitative reverse transcription polymerase chain reaction (FQ-RT-PCR) were used to assay 33 differentially expressed genes which were screened out using microarray analysis and were not present in the retinal cDNA or the Expressed Sequence Tags (EST) database of the National Eye Institute (NEI) Genebank.Results Nine of the 33 genes belonged to EST or the unknown cDNA fragments, and the remaining belonged to the novel genes in the retina. During the human retinal development 17 genes were down-regulated, 6 were up-regulated and the remaining 10 were relatively unchanged. Most of the genes expressed in all layers of the retina at the gestation stage, and in the fully developed retina some genes examined did show higher expression level in certain specific cells and structures such as retinal ganglion cells or the outer segment of photoreceptor cells.Conclusion The gene expression profile during retinal development possesses temporal and spatial distribution features, which can provide experimental evidence for further research of the functions of those genes.

  9. Therapeutic effect of bFGF on retina ischemia-reperfusion injury

    Institute of Scientific and Technical Information of China (English)

    牛膺筠; 赵岩松; 高云霞; 周占宇; 王红云; 袁春燕

    2004-01-01

    Background Basic fibroblast growth factor (bFGF) plays important roles in retina degeneration, light injury, mechanical injury, especially in retina ischemia-reperfusion injury (RIRI). This study was to investigate the therapeutical effect of bFGF on RIRI and its mechanisms. Methods Experimental RIRI was induced by increasing intraocular pressure (lOP) in the eyes of 48 rats. These rats were divided into normal control, ischemia-reperfusion and bFGF-treated groups. Histological and ultrastructural changes of in the retina of different groups were observed, and the number of retinal ganglion cells (RGCs) was quantitatively analyzed under microscopy. Apoptotic cells were detected using the TdT-dUTP terminal nick-end labeling (TUNEL) method. The expression of caspase-3 was determined by streptavidin peroxidase (SP) immunohistochemistry. Atomic absorption spectrum method was used to evaluate the intracellular calcium changes. Results At the early stage of retinal ischemia-reperfusion injury, retina edema in the treated group was significantly eliminated compared with the untreated ischemic animals. RGCs in the bFGF-treated group was more than those in the untreated ischemic group during the post-reperfusion stages. In ischemic group, apoptotic cells could be found at 6th hours after reperfusion and reached the peak at 24th hours. At 72th hours no apoptotic cells could be found. The changes in caspase-3 expression had a similar manner. The intracellular calcium of rat retina began to increase at l th hour, reached the peak at 24 hours, and began to decease at 72th hours. The change of the three markers in the treatment group showed a similar pattern, but they were all relatively less obvious. Conclusion Apoptosis may play a vital role in RIRI. bFGF may has therapeutical effects on RIRI by inhibiting the increase of intracellular calciums and caspase-3 expression.

  10. Ptf1a triggers GABAergic neuronal cell fates in the retina

    Directory of Open Access Journals (Sweden)

    Parain Karine

    2007-10-01

    Full Text Available Abstract Background In recent years, considerable knowledge has been gained on the molecular mechanisms underlying retinal cell fate specification. However, hitherto studies focused primarily on the six major retinal cell classes (five types of neurons of one type of glial cell, and paid little attention to the specification of different neuronal subtypes within the same cell class. In particular, the molecular machinery governing the specification of the two most abundant neurotransmitter phenotypes in the retina, GABAergic and glutamatergic, is largely unknown. In the spinal cord and cerebellum, the transcription factor Ptf1a is essential for GABAergic neuron production. In the mouse retina, Ptf1a has been shown to be involved in horizontal and most amacrine neurons differentiation. Results In this study, we examined the distribution of neurotransmitter subtypes following Ptf1a gain and loss of function in the Xenopus retina. We found cell-autonomous dramatic switches between GABAergic and glutamatergic neuron production, concomitant with profound defects in the genesis of amacrine and horizontal cells, which are mainly GABAergic. Therefore, we investigated whether Ptf1a promotes the fate of these two cell types or acts directly as a GABAergic subtype determination factor. In ectodermal explant assays, Ptf1a was found to be a potent inducer of the GABAergic subtype. Moreover, clonal analysis in the retina revealed that Ptf1a overexpression leads to an increased ratio of GABAergic subtypes among the whole amacrine and horizontal cell population, highlighting its instructive capacity to promote this specific subtype of inhibitory neurons. Finally, we also found that within bipolar cells, which are typically glutamatergic interneurons, Ptf1a is able to trigger a GABAergic fate. Conclusion Altogether, our results reveal for the first time in the retina a major player in the GABAergic versus glutamatergic cell specification genetic pathway.

  11. Otx2 gene deletion in adult mouse retina induces rapid RPE dystrophy and slow photoreceptor degeneration.

    Directory of Open Access Journals (Sweden)

    Francis Béby

    Full Text Available BACKGROUND: Many developmental genes are still active in specific tissues after development is completed. This is the case for the homeobox gene Otx2, an essential actor of forebrain and head development. In adult mouse, Otx2 is strongly expressed in the retina. Mutations of this gene in humans have been linked to severe ocular malformation and retinal diseases. It is, therefore, important to explore its post-developmental functions. In the mature retina, Otx2 is expressed in three cell types: bipolar and photoreceptor cells that belong to the neural retina and retinal pigment epithelium (RPE, a neighbour structure that forms a tightly interdependent functional unit together with photoreceptor cells. METHODOLOGY/PRINCIPAL FINDINGS: Conditional self-knockout was used to address the late functions of Otx2 gene in adult mice. This strategy is based on the combination of a knock-in CreERT2 allele and a floxed allele at the Otx2 locus. Time-controlled injection of tamoxifen activates the recombinase only in Otx2 expressing cells, resulting in selective ablation of the gene in its entire domain of expression. In the adult retina, loss of Otx2 protein causes slow degeneration of photoreceptor cells. By contrast, dramatic changes of RPE activity rapidly occur, which may represent a primary cause of photoreceptor disease. CONCLUSIONS: Our novel mouse model uncovers new Otx2 functions in adult retina. We show that this transcription factor is necessary for long-term maintenance of photoreceptors, likely through the control of specific activities of the RPE.

  12. Circadian organization of the mammalian retina: from gene regulation to physiology and diseases.

    Science.gov (United States)

    McMahon, Douglas G; Iuvone, P Michael; Tosini, Gianluca

    2014-03-01

    The retinal circadian system represents a unique structure. It contains a complete circadian system and thus the retina represents an ideal model to study fundamental questions of how neural circadian systems are organized and what signaling pathways are used to maintain synchrony of the different structures in the system. In addition, several studies have shown that multiple sites within the retina are capable of generating circadian oscillations. The strength of circadian clock gene expression and the emphasis of rhythmic expression are divergent across vertebrate retinas, with photoreceptors as the primary locus of rhythm generation in amphibians, while in mammals clock activity is most robust in the inner nuclear layer. Melatonin and dopamine serve as signaling molecules to entrain circadian rhythms in the retina and also in other ocular structures. Recent studies have also suggested GABA as an important component of the system that regulates retinal circadian rhythms. These transmitter-driven influences on clock molecules apparently reinforce the autonomous transcription-translation cycling of clock genes. The molecular organization of the retinal clock is similar to what has been reported for the SCN although inter-neural communication among retinal neurons that form the circadian network is apparently weaker than those present in the SCN, and it is more sensitive to genetic disruption than the central brain clock. The melatonin-dopamine system is the signaling pathway that allows the retinal circadian clock to reconfigure retinal circuits to enhance light-adapted cone-mediated visual function during the day and dark-adapted rod-mediated visual signaling at night. Additionally, the retinal circadian clock also controls circadian rhythms in disk shedding and phagocytosis, and possibly intraocular pressure. Emerging experimental data also indicate that circadian clock is also implicated in the pathogenesis of eye disease and compelling experimental data

  13. Alzheimer’s Disease-Related Protein Expression in the Retina of Octodon degus

    Science.gov (United States)

    Du, Lucia Y.; Chang, Lily Y-L.; Ardiles, Alvaro O.; Tapia-Rojas, Cheril; Araya, Joaquin; Inestrosa, Nibaldo C.

    2015-01-01

    New studies show that the retina also undergoes pathological changes during the development of Alzheimer’s disease (AD). While transgenic mouse models used in these previous studies have offered insight into this phenomenon, they do not model human sporadic AD, which is the most common form. Recently, the Octodon degus has been established as a sporadic model of AD. Degus display age-related cognitive impairment associated with Aβ aggregates and phosphorylated tau in the brain. Our aim for this study was to examine the expression of AD-related proteins in young, adult and old degus retina using enzyme-linked or fluorescence immunohistochemistry and to quantify the expression using slot blot and western blot assays. Aβ4G8 and Aβ6E10 detected Aβ peptides in some of the young animals but the expression was higher in the adults. Aβ peptides were observed in the inner and outer segment of the photoreceptors, the nerve fiber layer (NFL) and ganglion cell layer (GCL). Expression was higher in the central retinal region than in the retinal periphery. Using an anti-oligomer antibody we detected Aβ oligomer expression in the young, adult and old retina. Immunohistochemical labeling showed small discrete labeling of oligomers in the GCL that did not resemble plaques. Congo red staining did not result in green birefringence in any of the animals analyzed except for one old (84 months) animal. We also investigated expression of tau and phosphorylated tau. Expression was seen at all ages studied and in adults it was more consistently observed in the NFL-GCL. Hyperphosphorylated tau detected with AT8 antibody was significantly higher in the adult retina and it was localized to the GCL. We confirm for the first time that Aβ peptides and phosphorylated tau are expressed in the retina of degus. This is consistent with the proposal that AD biomarkers are present in the eye. PMID:26267479

  14. Stem cell-based delivery of brain-derived neurotrophic factor gene in the rat retina.

    Science.gov (United States)

    Park, Hae-Young Lopilly; Kim, Jie Hyun; Sun Kim, Hwa; Park, Chan Kee

    2012-08-21

    As an alternative to a viral vector, the application of stem cells to transfer specific genes is under investigation in various organs. Using this strategy may provide more effective method to supply neurotrophic factor to the neurodegenerative diseases caused by neurotrophic factor deprivation. This study investigated the possibility and efficacy of stem cell-based delivery of the brain-derived neurotrophic factor (BDNF) gene to rat retina. Rat BDNF cDNA was transduced into rat bone marrow mesenchymal stem cells (rMSCs) using a retroviral vector. Its incorporation into the experimental rat retina and the expression of BDNF after intravitreal injection or subretinal injection were detected by real-time PCR, western blot analysis, and immunohistochemical staining. For the incorporated rMSCs, retinal-specific marker staining was performed to investigate the changes in morphology and the characteristics of the stem cells. Transduction of the rMSCs by retrovirus was effective, and the transduced rMSCs expressed high levels of the BDNF gene and protein. The subretinal injection of rMSCs produced rMSC migration and incorporation into the rat retina (about 15.7% incorporation rate), and retinal BDNF mRNA and protein expression was increased at 4 weeks after transplantation. When subretinal injection of rMSCs was applied to axotomized rat retina, it significantly increased the expression of BDNF until 4 weeks after transplantation. Some of the transplanted rMSCs exhibited morphological changes, but the retinal-specific marker stain was not sufficient to indicate whether neuronal differentiation had occurred. Using mesenchymal stem cells to deliver the BDNF gene to the retina may provide new treatment for glaucoma.

  15. Alzheimer's Disease-Related Protein Expression in the Retina of Octodon degus.

    Directory of Open Access Journals (Sweden)

    Lucia Y Du

    Full Text Available New studies show that the retina also undergoes pathological changes during the development of Alzheimer's disease (AD. While transgenic mouse models used in these previous studies have offered insight into this phenomenon, they do not model human sporadic AD, which is the most common form. Recently, the Octodon degus has been established as a sporadic model of AD. Degus display age-related cognitive impairment associated with Aβ aggregates and phosphorylated tau in the brain. Our aim for this study was to examine the expression of AD-related proteins in young, adult and old degus retina using enzyme-linked or fluorescence immunohistochemistry and to quantify the expression using slot blot and western blot assays. Aβ4G8 and Aβ6E10 detected Aβ peptides in some of the young animals but the expression was higher in the adults. Aβ peptides were observed in the inner and outer segment of the photoreceptors, the nerve fiber layer (NFL and ganglion cell layer (GCL. Expression was higher in the central retinal region than in the retinal periphery. Using an anti-oligomer antibody we detected Aβ oligomer expression in the young, adult and old retina. Immunohistochemical labeling showed small discrete labeling of oligomers in the GCL that did not resemble plaques. Congo red staining did not result in green birefringence in any of the animals analyzed except for one old (84 months animal. We also investigated expression of tau and phosphorylated tau. Expression was seen at all ages studied and in adults it was more consistently observed in the NFL-GCL. Hyperphosphorylated tau detected with AT8 antibody was significantly higher in the adult retina and it was localized to the GCL. We confirm for the first time that Aβ peptides and phosphorylated tau are expressed in the retina of degus. This is consistent with the proposal that AD biomarkers are present in the eye.

  16. Spontaneous glial calcium waves in the retina develop over early adulthood.

    Science.gov (United States)

    Kurth-Nelson, Zeb L; Mishra, Anusha; Newman, Eric A

    2009-09-01

    Intercellular glial Ca(2+) waves constitute a signaling pathway between glial cells. Artificial stimuli have previously been used to evoke these waves, and their physiological significance has been questioned. We report here that Ca(2+) waves occur spontaneously in rat retinal glial cells, both in the isolated retina and in vivo. These spontaneous waves are propagated by ATP release. In the isolated retina, suramin (P2 receptor antagonist) reduces the frequency of spontaneous wave generation by 53%, and apyrase (ATP-hydrolyzing enzyme) reduces frequency by 95-100%. Luciferin-luciferase chemiluminescence reveals waves of ATP matching the spontaneous Ca(2+) waves, indicating that ATP release occurs as spontaneous Ca(2+) waves are generated. Wave generation also depends on age. Spontaneous wave frequency rises from 0.27 to 1.0 per minute per mm(2), as rats age from 20 to 120 d. The sensitivity of glia to ATP does not increase with age, but the ATP released by evoked waves is 31% greater in 120-d-old than in 20-d-old rats, suggesting that increased ATP release in older animals could account for the higher frequency of wave generation. Simultaneous imaging of glial Ca(2+) and arterioles in the isolated retina demonstrates that spontaneous waves alter vessel diameter, implying that spontaneous waves may have a significant impact on retinal physiology. Spontaneous intercellular glial Ca(2+) waves also occur in the retina in vivo, with frequency, speed, and diameter similar to the isolated retina. Increased spontaneous wave occurrence with age suggests that wave generation may be related to retinal pathology.

  17. Effects of ascorbic acid on UV light-mediated photoreceptor damage in isolated rat retina.

    Science.gov (United States)

    Tokuda, Kazuhiro; Zorumski, Charles F; Izumi, Yukitoshi

    2007-03-01

    Concerns have been raised about whether operating microscopes and endoillumination used during ophthalmic surgeries contribute to retinal damage. Despite the recognition that ascorbic acid (vitamin C) helps to protect the eye from light and the abundance of vitamin C in the retina, artificial aqueous humors used during surgery only contain the antioxidant glutathione. To test whether inclusion of antioxidants other than glutathione in surgical solutions might help to preserve retinal integrity, we studied the effects of vitamin C on acute toxicity in isolated rat retinas. Male Sprague-Dawley rats (PND 30+/-2) were sacrificed for retinal isolation. In the presence or absence of vitamin C (1 or 3 mM), retinas were exposed to 302 nm ultraviolet B (UVB) light for 1 h and were incubated for a total of 5 h at 30 degrees C. Retinal damage was assessed by morphological examination and biochemical assay measuring the amount of lactate dehydrogenase (LDH) released from injured cells. In control retinas, LDH release was significantly increased after UVB exposure. The presence of 1 mM vitamin C in the incubation media significantly reduced LDH release during the post-incubation period following UV exposure. No difference was found between 1 and 3 mM vitamin C. Microscopic examination revealed that disorganization in the outer nuclear layer after UVB exposure was markedly attenuated by administration of 1 mM vitamin C. Vitamin C (1 mM), a concentration found in the anterior chamber in humans, but not glutathione, prevented phototoxic injury following UV exposure. Although vitamin C itself cannot be used in intraocular irrigating solutions because of adverse interactions with iron released during bleeding, inclusion of antioxidants equivalent to vitamin C should be considered to help protect the retina from intraoperative light toxicity.

  18. Cell differentiation in the retina of an epibenthonic teleost, the Tench (Tinca tinca, Linneo 1758).

    Science.gov (United States)

    Bejarano-Escobar, Ruth; Blasco, Manuel; DeGrip, Willem J; Martín-Partido, Gervasio; Francisco-Morcillo, Javier

    2009-09-01

    Here we present a detailed study of the major events in the retinal histogenesis in a freshwater epibenthonic fish species, the Tench (Tinca tinca, Linneo 1758) during embryonic, prolarval, larval, and juvenile stages, using classical histological and immunohistological methods, providing a complete neurochemical characterization of retinal cells. We find a morphologically undifferentiated retina during embryonic stages and even at the hatching stage (postnatal day 0, P0). However, the emergence of the different retinal layers occurs in the first postnatal day (P1). Proliferating PCNA-positive cells are found in the retina of all postnatal individuals included in the present study, located in the circumferential germinal zone (CGZ), and in sparse cells dispersed throughout the inner nuclear layer (INL) and the outer nuclear layer (ONL). All neurochemical markers used start to express between P0 and P2. Anti-opsin, -alpha-protein kinase C, -alpha-tyrosine hydroxylase, -glutamine synthetase antibodies stain selectively different subpopulations of photoreceptor, bipolar, amacrine, and Müller cells respectively. Parvalbumin immunoreactivity is detected in amacrine and displaced amacrine cells. Several subpopulations of calretinin-positive ganglion, amacrine, and bipolar cells are detected in tench retina. Islet1 expression is confined to the nuclei of subpopulations of ganglion, amacrine, bipolar, and horizontal cells. All the maturational events described are first detected in the central retina and, as development progresses, they spread to the rest of the retina following a central-to-peripheral gradient. Therefore, tench postnatal retinal differentiation is a remarkable process not observed in the more common models of teleosts used in developmental biology.

  19. Feasibility of 99mTc-TRODAT-1 Micro-SPECT imaging of dopamine transporter in animal retinas

    Institute of Scientific and Technical Information of China (English)

    ZHAO Juan; QI Yujin; DAI Qiusheng; ZHANG Xuezhu; QU Xiaomei; HUANG Jia; LIU Xingdang

    2008-01-01

    In this paper, 99mTc-TRODAT-1 Micro-SPECT (single-photon emission computed tomography) was used for imaging dopamine transporter (DAT) in retinas and to investigate the changes of DAT in retinas of guinea pigs with form deprivation myopia. Pigmented guinea pigs aged 3 weeks were devided into form deprivation myopia (FDM) group (n=6) and normal control group (n=6). The test group wore translucent goggles randomly for 4 weeks,and both groups underwent biometric measurement (refraction and axial length) before and after the experiment.Micro-SPECT retinas imaging was performed at the 4th week after injection of 99nTc-TRODAT-1. The retinas were clearly resolved in the images. The ratio of 99mTc-TRODAT-1 uptake in the myopic retinas (11.55±2.80) was 3.64±1.40 lower than that in the control eye (15.20±1.98), and 2.35+1.05 lower than that in the fellow eyes (13.90±2.04). The results showed that 99mTc-TRODAT-1 Micro-SPECT eye imaging can be used to trace the distribution and changes of DAT in retina, and DAT in the myopic retinas were lower than that in the normal control eyes and fellow eyes. Micro-SPECT may provide a new approach for further studies on the role of dopamine system in the experimental myopia.

  20. CD74 indicates microglial activation in experimental diabetic retinopathy and exogenous methylglyoxal mimics the response in normoglycemic retina.

    Science.gov (United States)

    Wang, Jing; Lin, Jihong; Schlotterer, Andreas; Wu, Liang; Fleming, Thomas; Busch, Stephanie; Dietrich, Nadine; Hammes, Hans-Peter

    2014-10-01

    Diabetes induces vasoregression, neurodegeneration and glial activation in the retina. Formation of advanced glycation endoproducts (AGEs) is increased in diabetes and contributes to the pathogenesis of diabetic retinopathy. CD74 is increased in activated microglia in a rat model developing both neurodegeneration and vasoregression. In this study, we aimed at investigating whether glucose and major AGE precursor methylglyoxal induce increased CD74 expression in the retina. Expression of CD74 in retinal microglia was analyzed in streptozotocin-diabetic rats by wholemount immunofluorescence. Nondiabetic mice were intravitreally injected with methylglyoxal. Expression of CD74 was studied by retinal wholemount immunofluorescence and quantitative real-time PCR, 48 h after the injection. CD74-positive cells were increased in diabetic 4-month retinas. These cells represented a subpopulation of CD11b-labeled activated microglia and were mainly located in the superficial vascular layer (13.7-fold increase compared to nondiabetic group). Methylglyoxal induced an 9.4-fold increase of CD74-positive cells in the superficial vascular layer and elevated gene expression of CD74 in the mouse retina 2.8-fold. In summary, we identified CD74 as a microglial activation marker in the diabetic retina. Exogenous methylglyoxal mimics the response in normoglycemic retina. This suggests that methylglyoxal is important in mediating microglial activation in the diabetic retina.

  1. Chondroitin sulfate proteoglycans and microglia prevent migration and integration of grafted Müller stem cells into degenerating retina.

    Science.gov (United States)

    Singhal, Shweta; Lawrence, Jean M; Bhatia, Bhairavi; Ellis, James S; Kwan, Anthony S; Macneil, Angus; Luthert, Philip J; Fawcett, James W; Perez, Maria-Thereza; Khaw, Peng T; Limb, G Astrid

    2008-04-01

    At present, there are severe limitations to the successful migration and integration of stem cells transplanted into the degenerated retina to restore visual function. This study investigated the potential role of chondroitin sulfate proteoglycans (CSPGs) and microglia in the migration of human Müller glia with neural stem cell characteristics following subretinal injection into the Lister hooded (LH) and Royal College of Surgeons (RCS) rat retinae. Neonate LH rat retina showed minimal baseline microglial accumulation (CD68-positive cells) that increased significantly 2 weeks after transplantation (p cell layer (GCL) and inner plexiform layer. In contrast, nontransplanted 5-week-old RCS rat retina showed considerable baseline microglial accumulation in the outer nuclear layer (ONL) and photoreceptor outer segment debris zone (DZ) that further increased (p retina 2 weeks after transplantation. Marked deposition of the N-terminal fragment of CSPGs, as well as neurocan and versican, was observed in the DZ of 5-week-old RCS rat retinae, which contrasted with the limited expression of these proteins in the GCL of the adult and neonate LH rat retinae. Staining for CSPGs and CD68 revealed colocalization of these two molecules in cells infiltrating the ONL and DZ of the degenerating RCS rat retina. Enhanced immune suppression with oral prednisolone and intraperitoneal injections of indomethacin caused a reduction in the number of microglia but did not facilitate Müller stem cell migration. However, injection of cells with chondroitinase ABC combined with enhanced immune suppression caused a dramatic increase in the migration of Müller stem cells into all the retinal cell layers. These observations suggest that both microglia and CSPGs constitute a barrier for stem cell migration following transplantation into experimental models of retinal degeneration and that control of matrix deposition and the innate microglial response to neural retina degeneration may need to be

  2. Ganglion cell size and distribution in the retina of the two-toed sloth (Choloepus didactylus L.).

    Science.gov (United States)

    Andrade-da-Costa, B L; Pessoa, V F; Bousfield, J D; Clarke, R J

    1989-01-01

    The distribution of ganglion cell densities and sizes was studied in Nissl-stained flat-mount retinae of the two-toed sloth. The area centralis, a weak specialization with low ganglion cell density, is located in the temporal retina close to the center of the eye. The presence of a visual streak was noted. The distribution of different ganglion cell sizes was approximately equal throughout the retina. Although the retinal organization differs from that of the closely related three-toed sloth, the presumed function of retinal specializations in both species is to guide limb movements by permitting visualization of the branch along which the animal is climbing.

  3. Doublecortin is widely expressed in the developing and adult retina of sharks.

    Science.gov (United States)

    Sánchez-Farías, Nuria; Candal, Eva

    2015-05-01

    Doublecortin (DCX) is a microtubule-associated protein that has been considered a marker for neuronal precursors and young migrating neurons during the development of the central nervous system and in adult neurogenic niches. The retina of fishes represents an accessible, continuously growing and highly structured (layered) part of the central nervous system and, therefore, offers an exceptional model to extend our knowledge on the possible role of DCX in promoting neurogenesis and migration to appropriate layers. We have analyzed the distribution of DCX in the embryonic and postembryonic retina of a small shark, the lesser spotted dogfish Scyliorhinus canicula, by means of immunohistochemistry. We investigated the relationship between DCX expression and the neurogenic state of DCX-labeled cells by exploring its co-localization with the proliferation marker PCNA (proliferating cell nuclear antigen) and the marker of neuronal differentiation HuC/D. Since radially migrating neurons use radial glial fibers as substrate, we explored the possible correlation between DCX expression and cell migration along radial glia by comparing its expression with that of the glial marker GFAP (glial fibrillary acidic protein). Additionally, we characterized DCX-expressing cells by double immunocytochemistry using antibodies against Calbindin (a marker for mature bipolar and horizontal cells in this species) and Pax6, which has been proposed as a regulator of cell proliferation, cell differentiation, and neuron diversification in the neural retina of sharks. Strong DCX immunoreactivity was observed in immature cells and cell processes, at a time when retinal cells were not yet organized into different laminae. DCX was also found in subsets of mature ganglion, amacrine, bipolar and horizontal cells long after they had exited the cell cycle, a pattern that was maintained in juveniles and adults. Our results on DCX expression in the retina are compatible with a role for DCX in cell

  4. Age-related structural abnormalities in the human retina-choroid complex revealed by two-photon excited autofluorescence imaging.

    Science.gov (United States)

    Han, Meng; Giese, Guenter; Schmitz-Valckenberg, Steffen; Bindewald-Wittich, Almut; Holz, Frank G; Yu, Jiayi; Bille, Josef F; Niemz, Markolf H

    2007-01-01

    The intensive metabolism of photoreceptors is delicately maintained by the retinal pigment epithelium (RPE) and the choroid. Dysfunction of either the RPE or choroid may lead to severe damage to the retina. Two-photon excited autofluorescence (TPEF) from endogenous fluorophores in the human retina provides a novel opportunity to reveal age-related structural abnormalities in the retina-choroid complex prior to apparent pathological manifestations of age-related retinal diseases. In the photoreceptor layer, the regularity of the macular photoreceptor mosaic is preserved during aging. In the RPE, enlarged lipofuscin granules demonstrate significantly blue-shifted autofluorescence, which coincides with the depletion of melanin pigments. Prominent fibrillar structures in elderly Bruch's membrane and choriocapillaries represent choroidal structure and permeability alterations. Requiring neither slicing nor labeling, TPEF imaging is an elegant and highly efficient tool to delineate the thick, fragile, and opaque retina-choroid complex, and may provide clues to the trigger events of age-related macular degeneration.

  5. 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...... cells from the neural retina of the domestic pig and transplanted them to the laser-injured retina of allorecipients. Prior to grafting, immunocytochemical analysis showed that cultured porcine RPCs widely expressed neural cell adhesion molecule, as well as markers consistent with immature neural cells...... immune suppression. Grafted cells expressed transducin, recoverin, and rhodopsin in the pig subretinal space, suggestive of differentiation into photoreceptors or, in a few cases, migrated into the neural retina and extended processes, the latter typically showing radial orientation. These results...

  6. 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.

  7. 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.

  8. Aberration-free volumetric high-speed imaging of in vivo retina

    Science.gov (United States)

    Hillmann, Dierck; Spahr, Hendrik; Hain, Carola; Sudkamp, Helge; Franke, Gesa; Pfäffle, Clara; Winter, Christian; Hüttmann, Gereon

    2016-10-01

    Certain topics in research and advancements in medical diagnostics may benefit from improved temporal and spatial resolution during non-invasive optical imaging of living tissue. However, so far no imaging technique can generate entirely diffraction-limited tomographic volumes with a single data acquisition, if the target moves or changes rapidly, such as the human retina. Additionally, the presence of aberrations may represent further difficulties. We show that a simple interferometric setup-based on parallelized optical coherence tomography-acquires volumetric data with 10 billion voxels per second, exceeding previous imaging speeds by an order of magnitude. This allows us to computationally obtain and correct defocus and aberrations resulting in entirely diffraction-limited volumes. As demonstration, we imaged living human retina with clearly visible nerve fiber layer, small capillary networks, and photoreceptor cells. Furthermore, the technique can also obtain phase-sensitive volumes of other scattering structures at unprecedented acquisition speeds.

  9. Where do the photons collapse - in the retina or in the brain cortex?

    CERN Document Server

    Georgiev, D D

    2002-01-01

    While looking for evidence of quantum coherent states within the brain many quantum mind advocates proposed experiments based on the assumption that the coherence state of natural light could somehow be preserved thorough the neural processing, or in other words they suppose that photons collapse not in the retina, but in the brain cortex. In this paper I show that photons collapse within the retina and subsequent processing of information at the level of neural membranes proceeds. The changes of the membrane potential of the neurons in the primary sensory cortical regions are shown to be relevant to inputting sensory information, which is converted into microtubule subunits pattern and specific quantum states. The role of the associative cortical regions in the conscious experience is thoroughly revised. One of the strangest observations, namely the existence of the so called grandmother cells, is explained by quantum state processing. The question why classical computing is needed at all gets unexpected ans...

  10. CHANGES OF THE THICKNESS OF RETINA NERVE FIBER LAYER IN ALZHEIMER’S DISEASE

    Institute of Scientific and Technical Information of China (English)

    陈燕; 孙悦

    2013-01-01

    <正>Objective To determine the changes of retina nerve fiber thickness with optical coherence tomography(OCT) in Alzheimer’s disease(AD) patients.Methods OCT was used to measure the thickness of retinal nerve fiber layer(RNFL) from 38 AD patients and 26 healthy age-matched controls.The corrected visual acuity and intraocular pressure were measured and the dilated fundus examinations were also performed in those subjects.Results Compared with healthy age-matched controls,the RNFL thickness of AD patients(95.40±29.45) were much thinner than the controls(105.91±29.87)(P <().05),especially in superior quadrant,while no difference was found in the other retinal area.Conclusion Retinal nerve degeneration may be present in the retina of AD patients and this degeneration is likely localized preferentially to the superior quadrant.

  11. Differential effects of nitric oxide on rod and cone pathways in carp retina

    Institute of Scientific and Technical Information of China (English)

    叶冰; 杜久林; 杨雄里

    1997-01-01

    The effects of nitric oxide (NO) on electroretinograms and light responses of horizontal cells intra-cellularly recorded from isolated, superfused carp retinas were studied. Sodium nitroprusside (SNP), an NO donor, suppressed scotopic b wave, while enhancing photopic b wave, and the effects could be blocked by hemoglobin, an NO chelator. Furthermore, following SNP application, light responses of rod horizontal cells were reduced in size and those of cone horizontal cells were increased. These results suggest that NO suppresses the activity of rod pathway, but enhances that of cone pathway in the outer retina. Moreover, the effects of methylene blue, an inhibitor of soluble guanylate cyclase, on rod and cone horizontal cells were just opposite to those of SNP, implying that the effects of NO may be mediated by cGMP.

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

    Directory of Open Access Journals (Sweden)

    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. Developmental and mutational changes of glycoproteins in the mouse neuronal retina: studies with bovine galactosyltransferase.

    Science.gov (United States)

    Wallenfels, B

    1979-07-01

    Bovine galactosyltransferase (lactose synthase; EC 2.4.1.22) which catalyzes the transfer of galactose from UDPgalactose to glycoproteins with N-acetylglucosamine as the terminal residue of their oligosaccharide side chains was used to label glycoproteins of mouse retina with [14C]galactose. The glycoproteins were separated by isoelectric focusing in the first dimension and by sodium dodecyl sulfate gel electrophoresis in the second dimension. Their position on the gel was determined by autofluorography. With this method, quantitative as well as qualitative changes in the glycoprotein composition of the neuronal mouse retina during postnatal development were observed. Furthermore, it was found that the photoreceptor loss in mice with retinal degeneration was paralleled by the disappearance of certain glycoprotein bands.

  14. Aberration-free volumetric high-speed imaging of in vivo retina

    CERN Document Server

    Hillmann, Dierck; Hain, Carola; Sudkamp, Helge; Franke, Gesa; Pfäffle, Clara; Winter, Christian; Hüttmann, Gereon

    2016-01-01

    Research and medicine rely on non-invasive optical techniques to image living tissue with high resolution in space and time. But so far a single data acquisition could not provide entirely diffraction-limited tomographic volumes of rapidly moving or changing targets, which additionally becomes increasingly difficult in the presence of aberrations, e.g., when imaging retina in vivo. We show, that a simple interferometric setup based on parallelized optical coherence tomography acquires volumetric data with 10 billion voxels per second, exceeding previous imaging speeds by an order of magnitude. This allows us to computationally obtain and correct defocus and aberrations resulting in entirely diffraction-limited volumes. As demonstration, we imaged living human retina with clearly visible nerve fiber layer, small capillary networks, and photoreceptor cells, but the technique is also applicable to obtain phase-sensitive volumes of other scattering structures at unprecedented acquisition speeds.

  15. [Stem cells in adult retina--current state of research, future therapeutic prospects].

    Science.gov (United States)

    Machalińska, Anna; Zuba-Surma, Ewa K

    2009-01-01

    The latest research reports revealed the presence of stem/progenitor cells located in different regions of matured eye. They are able to differentiate into retinal pigment epithelium cells as well as neural structure of retina. These cells were identified in neurosensory retina, pigment epithelium and within cilliary body and iris epithelium. Moreover, it has been proved that Muller glia possess the potential of differentiation into retinal cells. These findings indicate the presence of potential mechanisms enabling retinal cell repopulation and retinal tissue regeneration. In the present work, the recent reports documenting the presence of different stem cell populations in eye have been reviewed, particularly focusing on recently identified very small embryonic-like stem cells (VSEL-SCs). The potential clinical applications of the residing stem cells and limitations of such therapeutic strategies have been also discussed.

  16. Readout circuit design of the retina-like CMOS image sensor

    Science.gov (United States)

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

    2015-02-01

    Readout circuit is designed for a special retina-like CMOS image sensor. To realize the pixels timing drive and readout of the sensor, the Altera's Cyclone II FPGA is used as a control chip. The voltage of the sensor is supported by a voltage chip initialized by SPI with AVR MCU system. The analog image signal outputted by the sensor is converted to digital image data by 12-bits A/D converter ADS807 and the digital data is memorized in the SRAM. Using the Camera-link image grabber, the data stored in SRAM is transformed to image shown on PC. Experimental results show the circuit works well on retina-like CMOS timing drive and image readout and images can be displayed properly on the PC.

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

    Institute of Scientific and Technical Information of China (English)

    LI QingLi; XUE YongQi; ZHANG JingFa; XIAO GongHai

    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 seotions 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.

  18. 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......Work in rodents has demonstrated that progenitor transplantation can achieve limited photoreceptor replacement in the mammalian retina; however, replication of these findings on a clinically relevant scale requires a large animal model. To evaluate the ability of porcine retinal progenitor cells...... 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...

  19. Regeneration of the retina: toward stem cell therapy for degenerative retinal diseases.

    Science.gov (United States)

    Jeon, Sohee; Oh, Il-Hoan

    2015-04-01

    Degenerative retinal diseases affect millions of people worldwide, which can lead to the loss of vision. However, therapeutic approaches that can reverse this process are limited. Recent efforts have allowed the possibility of the stem cell-based regeneration of retinal cells and repair of injured retinal tissues. Although the direct differentiation of pluripotent stem cells into terminally differentiated photoreceptor cells comprises one approach, a series of studies revealed the intrinsic regenerative potential of the retina using endogenous retinal stem cells. Muller glial cells, ciliary pigment epithelial cells, and retinal pigment epithelial cells are candidates for such retinal stem cells that can differentiate into multiple types of retinal cells and be integrated into injured or developing retina. In this review, we explore our current understanding of the cellular identity of these candidate retinal stem cells and their therapeutic potential for cell therapy against degenerative retinal diseases.

  20. Rax: Developmental and Daily Expression Patterns in the Rat Pineal Gland and Retina

    DEFF Research Database (Denmark)

    Rohde, Kristian; Klein, David C; Møller, Morten;

    2011-01-01

    Retina and anterior neural fold homeobox (Rax) gene encodes a transcription factor essential for vertebrate eye development. Recent microarray studies indicate that Rax is expressed in the adult rat pineal gland and retina. The present study reveals that Rax expression levels in the rat change...... significantly during retinal development with a peak occurring at embryonic day (E) 18, whereas Rax expression in the pineal is relatively delayed and not detectable until E20. In both tissues, Rax is expressed throughout postnatal development into adulthood. In the mature rat pineal gland, the abundance of Rax...... transcripts increases 2-fold during the light period with a peak occurring at dusk. These findings are consistent with the evidence that Rax is of functional importance in eye development and suggest a role of Rax in the developing pineal gland. In addition, it would appear possible that Rax contributes...

  1. The electroretinogram as a method for studying circadian rhythms in the mammalian retina

    Indian Academy of Sciences (India)

    Morven A. Cameron; Alun R. Barnard; Robert J. Lucas

    2008-12-01

    Circadian clocks are thought to regulate retinal physiology in anticipation of the large variation in environmental irradiance associated with the earth’s rotation upon its axis. In this review we discuss some of the rhythmic events that occur in the mammalian retina, and their consequences for retinal physiology. We also review methods of tracing retinal rhythmicity in vivo and highlight the electroretinogram (ERG) as a useful technique in this field. Principally, we discuss how this technique can be used as a quick and noninvasive way of assessing physiological changes that occur in the retina over the course of the day. We highlight some important recent findings facilitated by this approach and discuss its strengths and limitations.

  2. [Relationship between vitrectomy and the morphology and function of the retina].

    Science.gov (United States)

    Terasaki, Hiroko

    2003-12-01

    Pathological processes in the vitreous will be reflected in the morphology and function of the retina, and these processes can originate from sources outside the vitreous. The purpose of vitreous surgery is to remove the qualitatively and/or morphologically diseased vitreous. Successful vitrectomy will be manifested by an improvement in the structure and/or function of the retina. We have evaluated the morphology of the vitreoretinal interface, and the function of the retina before and after vitreous surgery. Plasmin-assisted vitrectomy was used in some cases to remove the diseased vitreous more efficiently and less invasively. The effect of this procedure was assessed by examining the morphology and function of the retina. First, the relationship between the qualitative and structural abnormality of the vitreous in macular diseases was studied. In aphakic/pseudophakic eyes with cystoid macular edema, there was a depression of retinal function over the entire retina which may have been caused by chemical mediators released into the vitreous. These mediators may have been produced by inflammation in the anterior segment of the eye. In eyes with an idiopathic macular hole, optical coherence tomographic (OCT) images suggested that the progression of the macular hole might depend on a balance between foveal adhesion and the posterior vitreous. Second, the efficacy, surgical damage, and limitations of vitreous surgery were investigated. The recovery of macular function was assessed by focal macular electroretinograms (FMERGs) after vitrectomy for epiretinal membrane, choroidal neovascularization, and diabetic macular edema. The concurrent examination by optical coherence tomography (OCT) suggested that a decrease in retinal thickness contributed to the functional recovery. Macular functional recovery was delayed and limited after macular translocation, diabetic macular edema, and internal limiting membrane peeling. Third, we studied the effect of plasmin

  3. 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.

  4. Bipolar cell pathways for color and luminance vision in a dichromatic mammalian retina.

    Science.gov (United States)

    Li, Wei; DeVries, Steven H

    2006-05-01

    The mammalian retina is fundamentally dichromatic, with trichromacy only recently emerging in some primates. In dichromats, an array of short wavelength-sensitive (S, blue) and middle wavelength-sensitive (M, green) cones is sampled by approximately ten bipolar cell types, and the sampling pattern determines how retinal ganglion cells and ultimately higher visual centers encode color and luminance. By recording from cone-bipolar cell pairs in the retina of the ground squirrel, we show that the bipolar cell types sample cone signals in three ways: one type receives input exclusively from S-cones, two types receive mixed S/M-cone input and the remaining types receive an almost pure M-cone signal. Bipolar cells that carry S- or M-cone signals can have a role in color discrimination and may contact color-opponent ganglion cells. Bipolar cells that sum signals from S- and M-cones may signal to ganglion cells that encode luminance.

  5. Modelación y simulación de la retina humana

    Directory of Open Access Journals (Sweden)

    Andrés Castaño

    2001-04-01

    Full Text Available

    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 electrónico que implemente el modelo y la solución numérica.

     

     

  6. Artificial design of three-dimensional retina-like tissue from dissociated cells of the mammalian retina by rotation-mediated cell aggregation.

    Science.gov (United States)

    Rothermel, Andrée; Biedermann, Thomas; Weigel, Winnie; Kurz, Randy; Rüffer, Markus; Layer, Paul G; Robitzki, Andrea Anneliese

    2005-01-01

    The goal of this study was to establish a reliable three-dimensional culture system for the mammalian retina that allows the analysis of retinal function and dysfunction. To produce three-dimensional retinal tissues in vitro, dissociated retinal cells of neonatal rats were maintained in culture dishes on a self-made orbital shaker. On the basis of well-defined rotation conditions, dissociated free-floating cells reaggregate in the center of the culture dish to form a multicellular cluster. Subsequently, cells begin to proliferate, whereby they form spherelike retinal tissues that grow to a size of 180-210 microm. Immunohistochemical characterization of mature retinal spheres revealed the presence of ganglion cells, amacrine cells, Müller cells, and rod photoreceptors, which are arranged in different retina-like layers. Although a small number of cells undergo programmed cell death, retinal spheres remain viable for at least 35 days in culture as revealed by fluorescein diacetate and TUNEL staining. Because most biological processes involved in tissue organization such as proliferation, differentiation, apoptosis, and survival are also observable in retinal spheres, the presented novel mammalian three-dimensional culture system is not only an outstanding model for basic research but may also be of great benefit for stem cell tissue engineering and the pharmaceutical industry.

  7. Type-1, but Not Type-5, Metabotropic Glutamate Receptors are Coupled to Polyphosphoinositide Hydrolysis in the Retina.

    Science.gov (United States)

    Romano, Maria Rosaria; Di Menna, Luisa; Scarselli, Pamela; Mascio, Giada; Madonna, Michele; Notartomaso, Serena; Puliti, Aldamaria; Bruno, Valeria; Battaglia, Giuseppe; Nicoletti, Ferdinando

    2016-04-01

    mGlu1 and mGlu5 metabotropic glutamate receptors are expressed in the vertebrate retina, and are co-localized in some retinal neurons. It is believed that both receptors are coupled to polyphosphoinositide (PI) hydrolysis in the retina and their function may diverge in some cells because of a differential engagement of downstream signaling molecules. Here, we show that it is only the mGlu1 receptor that is coupled to PI hydrolysis in the retina. We used either bovine retinal slices or intact mouse retinas challenged with the mixed mGlu1/5 receptor agonist, DHPG. In both models, DHPG-stimulated PI hydrolysis was abrogated by the selective mGlu1 receptor antagonist, JNJ16259685, but was insensitive to the mGlu5 receptor antagonist, MPEP. In addition, the PI response to DHPG was unchanged in the retina of mGlu5(-/-) mice but was abolished in the retina of crv4 mice lacking mGlu1 receptors. Stimulation of the mitogen-activated protein kinase pathway by DHPG in intact mouse retinas were also entirely mediated by mGlu1 receptors. Our data provide the first example of a tissue in which a biochemically detectable PI response is mediated by mGlu1, but not mGlu5, receptors. Hence, bovine retinal slices might be used as a model for the functional screening of mGlu1 receptor ligands. In addition, the mGlu1 receptor caters the potential as a drug target in the experimental treatment of degenerative disorders of the retina.

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

    Directory of Open Access Journals (Sweden)

    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

  9. Functional aspects of the somatostatinergic system in the retina and the potential therapeutic role of somatostatin in retinal disease

    OpenAIRE

    Casini, G.; Catalani, E.; M. Dal Monte; bagnoli, P

    2005-01-01

    The somatostatinergic system of the retina has been investigated in a variety of studies. A considerable amount of experimental evidence is available concerning the patterns of expression of somatostatin (SRIF) and its receptors in vertebrate retinas. However the functional roles of this peptidergic system in retinal physiology are far from being elucidated. Nonetheless, data have been provided concerning the regulatory action of SRIF on the excitability of...

  10. Transdifferentiation and survival of neural retina cells in relation to illumination.

    Science.gov (United States)

    Pritchard, D J

    1984-12-01

    Cultures of chicken embryo neural retina cells were exposed to light of different intensities and colours, in order to identify the wavelengths that promote cell degeneration and transdifferentiation into pigment epithelium. Blue and green light caused cell death; blue, green and yellow light enhanced transdifferentiation; red light had no effect. The relevance of these findings to retinal degeneration in man and the possible mediation of rhodopsin, riboflavin and other chromophores are discussed.

  11. ROLE OF CASPASE-3 IN ACUTE LIGHT DAMAGE TO RETINA OF RATS

    Institute of Scientific and Technical Information of China (English)

    Xiao Wang; Shi-xing Hu; Wei Li; Shao-chun Lin

    2007-01-01

    Objective To investigate the role of Caspase-3 in retinal damage caused by light exposure in rats.Methods Light injury to retina was induced by persistent exposure to illumination (intensity; 30000±50 lux) of operating microscope for 30 minutes in the right eyes of Sprague-Dawley rats. The pathological changes of retina were observed under optical and electron microscopies at different time points, which were 6 hours, 1,3,7,and 15 days after the light exposure. Apoptosis of retinal cells was analyzed by flow cytometry. The activity of Caspase-3 was evaluated by using the Caspase-3 assay kit. At the same time, the expression of Caspase-3 protease was determined with Western blot analysis.Results The examination results of optical and transmission electron microscopes showed that edema of inner and outer segments of the retina, espectially the chondriosome inside the inner segment, became obvious 6 hours after the light exposure. The change was deteriorated along with the increasing time. The structures of the discoidal valve dissociated in the outer segment simultaneously. Disorderly arranged nuclei, karyopycnosis, and thinning in the outer nuclear layer were observed. The retinal pogment epithelium almost disappeared during the later stage. The staining results of Annexin-V combined with PI demonstrated that the proportion of apoptotic cells increased with time. The proportion between 7th day (82.7%) and 15th day (80.4%), however, showed no significant difference. Caspase-3 became remarkably active with the lapse of time, which increased from 0.02 at 6th hour to the peak of 9.8 at 7th day before it started to descend. The Western blot detected a expression of the active form of Caspase-3 at 7th day and 15th day.Conclusion Apoptosis of photoreceptor cells is markedly involved in the light damage and Caspase-3 protease may play an important role in the apoptotic process of the retina after light exposure in rats.

  12. Patterned electrical stimulation of primate retina for the development of retinal prostheses

    OpenAIRE

    2012-01-01

    Epiretinal prostheses are designed to restore vision to people blinded by retinal degenerations, using electrical stimulation with an array of electrodes implanted on the surface of the retina to convey artificial visual signals to the brain. Current clinical prostheses provide limited visual function, in part because the activity that they generate is different from natural retinal responses to visual stimuli. An ideal retinal prosthesis would stimulate the retinal ganglion cells (RGCs) in a...

  13. Effect of increased oxygen tension on flicker-induced vasodilatation in the human retina.

    Science.gov (United States)

    Palkovits, Stefan; Told, Reinhard; Boltz, Agnes; Schmidl, Doreen; Popa Cherecheanu, Alina; Schmetterer, Leopold; Garhöfer, Gerhard

    2014-12-01

    In the retina, blood flow and neural activity are tightly coupled. Stimulation of the retina with flickering light is accompanied by an increase in blood flow. The current study seeks to investigate whether an increase in oxygen tension modulates flicker (FL)-induced vasodilatation in the human retina. A total of 52 healthy volunteers were included. Via a breathing mask, 100% oxygen (O(2)) was administered in one, a mixture of 8% carbon dioxide and 92% oxygen (C/O) in a second cohort. Retinal vessel diameters were measured with a Vessel Analyzer and FL responses were assessed before and during the breathing periods. At baseline, FL stimulation increased retinal vessel diameters by +3.7±2.3% in arteries and by +5.1±3.7% in veins. Breathing of C/O led to a decrease in arterial (-9.0±6.9%) and venous (-11.3±5.9%) vessel calibers. Flicker response was increased to 5.7±2.5% in arteries and to 8.6±4.1% in veins. Breathing of pure O2 induced a vasoconstriction of vessel diameters by -14.0±5.3% in arteries and -18.4±7.0% in veins and increased FL responses in arteries (+6.2±2.8%) and veins (+7.2±3.1%). Systemic hyperoxia increases FL-induced retinal vasodilatation in the retina. The mechanism by which oxygen modulates the hyperemic response to FL stimulation remains to be elucidated.

  14. 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.

  15. 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.

  16. Patterning the Retina of Drosophila Melanogaster for Color and Polarized Light Vision

    OpenAIRE

    Wernet, Mathias F.

    2004-01-01

    Across the animal kingdom, specialized sensory epithelia are used for photoreception, allowing individuals to interact with their environment based on visual cues. Generally, neuronal photoreceptor cells (PRs) are organized in the retina, a specialized part of body tissue exposed to the outside world, and transform the energy of incoming electromagnetic radiation into neuronal excitation. This process depends on the large family of opsin proteins which are required in PRs of all animal specie...

  17. Multipotent stem cells isolated from the adult mouse retina are capable of producing functional photoreceptor cells.

    Science.gov (United States)

    Li, Tianqing; Lewallen, Michelle; Chen, Shuyi; Yu, Wei; Zhang, Nian; Xie, Ting

    2013-06-01

    Various stem cell types have been tested for their potential application in treating photoreceptor degenerative diseases, such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Only embryonic stem cells (ESCs) have so far been shown to generate functional photoreceptor cells restoring light response of photoreceptor-deficient mice, but there is still some concern of tumor formation. In this study, we have successfully cultured Nestin(+)Sox2(+)Pax6(+) multipotent retinal stem cells (RSCs) from the adult mouse retina, which are capable of producing functional photoreceptor cells that restore the light response of photoreceptor-deficient rd1 mutant mice following transplantation. After they have been expanded for over 35 passages in the presence of FGF and EGF, the cultured RSCs still maintain stable proliferation and differentiation potential. Under proper differentiation conditions, they can differentiate into all the major retinal cell types found in the adult retina. More importantly, they can efficiently differentiate into photoreceptor cells under optimized differentiation conditions. Following transplantation into the subretinal space of slowly degenerating rd7 mutant eyes, RSC-derived photoreceptor cells integrate into the retina, morphologically resembling endogenous photoreceptors and forming synapases with resident retinal neurons. When transplanted into eyes of photoreceptor-deficient rd1 mutant mice, a RP model, RSC-derived photoreceptors can partially restore light response, indicating that those RSC-derived photoreceptors are functional. Finally, there is no evidence for tumor formation in the photoreceptor-transplanted eyes. Therefore, this study has demonstrated that RSCs isolated from the adult retina have the potential of producing functional photoreceptor cells that can potentially restore lost vision caused by loss of photoreceptor cells in RP and AMD.

  18. Edge Detection Model Based on Involuntary Eye Movements of the Eye-Retina System

    Directory of Open Access Journals (Sweden)

    András Róka

    2007-03-01

    Full Text Available Traditional edge-detection algorithms in image processing typically convolute afilter operator and the input image, and then map overlapping input image regions tooutput signals. Convolution also serves as a basis in biologically inspired (Sobel, Laplace,Canny algorithms. Recent results in cognitive retinal research have shown that ganglioncell receptive fields cover the mammalian retina in a mosaic arrangement, withinsignificant amounts of overlap in the central fovea. This means that the biologicalrelevance of traditional and widely adapted edge-detection algorithms with convolutionbasedoverlapping operator architectures has been disproved. However, using traditionalfilters with non-overlapping operator architectures leads to considerable losses in contourinformation. This paper introduces a novel, tremor-based retina model and edge-detectionalgorithm that reconciles these differences between the physiology of the retina and theoverlapping architectures used by today's widely adapted algorithms. The algorithm takesinto consideration data convergence, as well as the dynamic properties of the retina, byincorporating a model of involuntary eye tremors and the impulse responses of ganglioncells. Based on the evaluation of the model, two hypotheses are formulated on the highlydebated role of involuntary eye tremors: 1 The role of involuntary eye tremors hasinformation theoretical implications 2 From an information processing point of view, thefunctional role of involuntary eye-movements extends to more than just the maintenance ofaction potentials. Involuntary eye-movements may be responsible for the compensation ofinformation losses caused by a non-overlapping receptive field architecture. In support ofthese hypotheses, the article provides a detailed analysis of the model's biologicalrelevance, along with numerical simulations and a hardware implementation.

  19. Multipotent stem cells isolated from the adult mouse retina are capable of producing functional photoreceptor cells

    Institute of Scientific and Technical Information of China (English)

    Tianqing Li; Michelle Lewallen; Shuyi Chen; Wei Yu; Nian Zhang; Ting Xie

    2013-01-01

    Various stem cell types have been tested for their potential application in treating photoreceptor degenerative diseases,such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD).Only embryonic stem cells (ESCs) have so far been shown to generate functional photoreceptor cells restoring light response of photoreceptordeficient mice,but there is still some concern of tumor formation.In this study,we have successfully cultured Nestin+Sox2+Pax6+ multipotent retinal stem cells (RSCs) from the adult mouse retina,which are capable of producing functional photoreceptor cells that restore the light response of photoreceptor-deficient rd1 mutant mice following transplantation.After they have been expanded for over 35 passages in the presence of FGF and EGF,the cultured RSCs still maintain stable proliferation and differentiation potential.Under proper differentiation conditions,they can differentiate into all the major retinal cell types found in the adult retina.More importantly,they can efficiently differentiate into photoreceptor cells under optimized differentiation conditions.Following transplantation into the subretinal space of slowly degenerating rd7 mutant eyes,RSC-derived photoreceptor cells integrate into the retina,morphologically resembling endogenous photoreceptors and forming synapases with resident retinal neurons.When transplanted into eyes of photoreceptor-deficient rd1 mutant mice,a RP model,RSC-derived photoreceptors can partially restore light response,indicating that those RSC-derived photoreceptors are functional.Finally,there is no evidence for tumor formation in the photoreceptor-transplanted eyes.Therefore,this study has demonstrated that RSCs isolated from the adult retina have the potential of producing functional photoreceptor cells that can potentially restore lost vision caused by loss of photoreceptor cells in RP and AMD.

  20. 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.

  1. Eye enucleation and regeneration of neural retina in axolotl larvae (Ambystoma mexicanum).

    Science.gov (United States)

    Yew, D T

    1985-01-01

    The eyes of Axolotl larvae were enucleated at stages 30 and 37. Animals with single dorsomedian eyes resulted in the first case (i.e. stage 30). When a piece of pigment epithelium was re-implanted into stage 37 animals at the site of the lesion, limited regeneration was observed when the implant formed a vesicle, but, when the pigment epithelium remained "open" regeneration of the neural retina was extensive. The possible resons for this difference was discussed.

  2. Circuit design for the retina-like image sensor based on space-variant lens array

    Science.gov (United States)

    Gao, Hongxun; Hao, Qun; Jin, Xuefeng; Cao, Jie; Liu, Yue; Song, Yong; Fan, Fan

    2013-12-01

    Retina-like image sensor is based on the non-uniformity of the human eyes and the log-polar coordinate theory. It has advantages of high-quality data compression and redundant information elimination. However, retina-like image sensors based on the CMOS craft have drawbacks such as high cost, low sensitivity and signal outputting efficiency and updating inconvenience. Therefore, this paper proposes a retina-like image sensor based on space-variant lens array, focusing on the circuit design to provide circuit support to the whole system. The circuit includes the following parts: (1) A photo-detector array with a lens array to convert optical signals to electrical signals; (2) a strobe circuit for time-gating of the pixels and parallel paths for high-speed transmission of the data; (3) a high-precision digital potentiometer for the I-V conversion, ratio normalization and sensitivity adjustment, a programmable gain amplifier for automatic generation control(AGC), and a A/D converter for the A/D conversion in every path; (4) the digital data is displayed on LCD and stored temporarily in DDR2 SDRAM; (5) a USB port to transfer the data to PC; (6) the whole system is controlled by FPGA. This circuit has advantages as lower cost, larger pixels, updating convenience and higher signal outputting efficiency. Experiments have proved that the grayscale output of every pixel basically matches the target and a non-uniform image of the target is ideally achieved in real time. The circuit can provide adequate technical support to retina-like image sensors based on space-variant lens array.

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

    Directory of Open Access Journals (Sweden)

    Astrid Zayas-Santiago

    Full Text Available BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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

  4. Effects Of Primary Blast Overpressure On Retina And Optic Tract In Rats

    Directory of Open Access Journals (Sweden)

    James eDemar

    2016-04-01

    Full Text Available Blast has been the leading cause of injury, particularly traumatic brain injury and visual system injury, in combat operations in Iraq and Afghanistan. We determined the effect of shock tube-generated primary blast on retinal electrophysiology and on retinal and brain optic tract histopathology in a rat model.The amplitude of a- and b- waves on the electroretinogram (ERG for both right and left eyes were measured prior to a battlefield-simulation Friedlander-type blast wave and on 1, 7, and 14 days thereafter. Histopathologic findings of the right and left retina and the right and left optic tracts (2.8 mm post-optic chiasm were evaluated 14 days after the blast.For two experiments in which the right eye was oriented to the blast, the amplitude of ERG a- and b-waves at 7 days post-blast on the right side but not on the left side was diminished compared to that of sham animals (P=0.005-0.01 Histopathologic injury scores at 14 days post-blast for the right retina but not the left retina were higher than for sham animals (P=0.01, and histopathologic injury scores at 14 days for both optic tracts were markedly higher than for shams (P < 0.0001. Exposure of one eye to a blast wave, comparable to that causing human injury, produced injury to the retina as determined by ERG and histopathology, and to both post-chiasmatic optic tracts as determined by histopathology. This model may be useful for analyzing the effect of therapeutic interventions on retinal damage due to primary blast waves.

  5. Catalytic nanoceria are preferentially retained in the rat retina and are not cytotoxic after intravitreal injection.

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    Lily L Wong

    Full Text Available Cerium oxide nanoparticles (nanoceria possess catalytic and regenerative radical scavenging activities. The ability of nanoceria to maintain cellular redox balance makes them ideal candidates for treatment of retinal diseases whose development is tightly associated with oxidative damage. We have demonstrated that our stable water-dispersed nanoceria delay photoreceptor cell degeneration in rodent models and prevent pathological retinal neovascularization in vldlr mutant mice. The objectives of the current study were to determine the temporal and spatial distributions of nanoceria after a single intravitreal injection, and to determine if nanoceria had any toxic effects in healthy rat retinas. Using inductively-coupled plasma mass spectrometry (ICP-MS, we discovered that nanoceria were rapidly taken up by the retina and were preferentially retained in this tissue even after 120 days. We also did not observe any acute or long-term negative effects of nanoceria on retinal function or cytoarchitecture even after this long-term exposure. Because nanoceria are effective at low dosages, nontoxic and are retained in the retina for extended periods, we conclude that nanoceria are promising ophthalmic therapeutics for treating retinal diseases known to involve oxidative stress in their pathogeneses.

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

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    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.

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

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    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.

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

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    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.

  9. Image rotation-elimination based on a retina-like sensor

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    Cao, Fengmei; Lin, Yabin; Bai, Tingzhu; Wang, Fan

    2015-12-01

    The pixels of a retina-like sensor are arranged in concentric rings, and the output image is given in log-polar coordinates. Thus, additional residual errors will not be produced when the output image is rotated. Therefore, retina-like sensors have obvious advantages and many prospects for applications in the fields of image rotation and rapid image rotation-elimination. In this study, a theory concerning the image rotation of a retina-like sensor is proposed, and a solution based on the theory is presented and realized for eliminating image rotation caused by camera rotation. The camera rotation angle is obtained using a microelectromechanical systems digital accelerometer and gyroscope; only the readout sequence of each row from static random-access memory must be changed to achieve image rotation-elimination. Several image rotation-elimination experiments have been performed which show that the proposed solution is simple, accurate, and rapid. This rapid image rotation-elimination method can be used in fields that require higher image rotation-elimination processing speeds.

  10. Current Progress in Deciphering Importance of VLC-PUFA in the Retina.

    Science.gov (United States)

    Bennett, Lea D; Anderson, Robert E

    2016-01-01

    Stargardt-like macular dystrophy-3 (STGD3) is a juvenile-onset disease caused by mutations in ELOVL4 (elongation of very long fatty acids-4). This gene product catalyzes the elongation of long chain saturated and polyunsaturated fatty acids (LC-FAs and LC-PUFAs) into very long chain FAs and PUFAs (VLC-FAs and VLC-PUFAs). These mutations cause a frame shift in the ELOVL4 transcript, introducing a premature stop codon that results in the translation of a truncated protein that has lost a C-terminus endoplasmic reticulum (ER) retention/retrieval signal. The truncated protein is not targeted to the ER, the site of very long-chain PUFA (VLC-PUFA; 28-40 carbons) synthesis. Expression of the ELOVL4 gene is limited mainly to the brain, testis, skin, and photoreceptor cells of the retina. While the skin and brain contain very long chain saturated fatty acids (VLC-FAs), the other tissues expressing ELOVL4 contain VLC-PUFAs, with sperm and the retina having the highest levels. This review focuses on the current information available concerning the role of VLC-PUFAs in the retina.

  11. Tickling the retina: integration of subthreshold electrical pulses can activate retinal neurons

    Science.gov (United States)

    Sekhar, S.; Jalligampala, A.; Zrenner, E.; Rathbun, D. L.

    2016-08-01

    Objective. The field of retinal prosthetics has made major progress over the last decade, restoring visual percepts to people suffering from retinitis pigmentosa. The stimulation pulses used by present implants are suprathreshold, meaning individual pulses are designed to activate the retina. In this paper we explore subthreshold pulse sequences as an alternate stimulation paradigm. Subthreshold pulses have the potential to address important open problems such as fading of visual percepts when patients are stimulated at moderate pulse repetition rates and the difficulty in preferentially stimulating different retinal pathways. Approach. As a first step in addressing these issues we used Gaussian white noise electrical stimulation combined with spike-triggered averaging to interrogate whether a subthreshold sequence of pulses can be used to activate the mouse retina. Main results. We demonstrate that the retinal network can integrate multiple subthreshold electrical stimuli under an experimental paradigm immediately relevant to retinal prostheses. Furthermore, these characteristic stimulus sequences varied in their shape and integration window length across the population of retinal ganglion cells. Significance. Because the subthreshold sequences activate the retina at stimulation rates that would typically induce strong fading (25 Hz), such retinal ‘tickling’ has the potential to minimize the fading problem. Furthermore, the diversity found across the cell population in characteristic pulse sequences suggests that these sequences could be used to selectively address the different retinal pathways (e.g. ON versus OFF). Both of these outcomes may significantly improve visual perception in retinal implant patients.

  12. Rax : developmental and daily expression patterns in the rat pineal gland and retina.

    Science.gov (United States)

    Rohde, Kristian; Klein, David C; Møller, Morten; Rath, Martin F

    2011-09-01

    Retina and anterior neural fold homeobox (Rax) gene encodes a transcription factor essential for vertebrate eye development. Recent microarray studies indicate that Rax is expressed in the adult rat pineal gland and retina. The present study reveals that Rax expression levels in the rat change significantly during retinal development with a peak occurring at embryonic day 18, whereas Rax expression in the pineal is relatively delayed and not detectable until embryonic day 20. In both tissues, Rax is expressed throughout postnatal development into adulthood. In the mature rat pineal gland, the abundance of Rax transcripts increases 2-fold during the light period with a peak occurring at dusk. These findings are consistent with the evidence that Rax is of functional importance in eye development and suggest a role of Rax in the developing pineal gland. In addition, it would appear possible that Rax contributes to phenotype maintenance in the mature retina and pineal gland and may facilitate 24-h changes in the pineal transcriptome.

  13. Portable Raman spectroscopy using retina-safe (1550 nm) laser excitation

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    Brouillette, Carl; Smith, Wayne; Donahue, Michael; Huang, Hermes; Shende, Chetan; Sengupta, Atanu; Inscore, Frank; Patient, Michael; Farquharson, Stuart

    2012-06-01

    The use of portable Raman analyzers to identify unknown substances in the field has grown dramatically during the past decade. Measurements often require the laser beam to exit the confines of the sample compartment, which increases the potential of eye or skin damage. This is especially true for most commercial analyzers, which use 785 nm laser excitation. To overcome this safety concern, we have built a portable FT-Raman analyzer using a 1550 nm retina-safe excitation laser. Excitation at 1550 nm falls within the 1400 to 2000 nm retina-safe range, so called because the least amount of damage to the eye occurs in this spectral region. In contrast to wavelengths below 1400 nm, the retina-safe wavelengths are not focused by the eye, but are absorbed by the cornea, aqueous and vitreous humor. Here we compare the performance of this system to measurements of explosives at shorter wavelengths, as well as its ability to measure surface-enhanced Raman spectra of several chemicals, including the food contaminant melamine.

  14. Cannabinoid CB1 receptor signaling dichotomously modulates inhibitory and excitatory synaptic transmission in rat inner retina.

    Science.gov (United States)

    Wang, Xiao-Han; Wu, Yi; Yang, Xiao-Fang; Miao, Yanying; Zhang, Chuan-Qiang; Dong, Ling-Dan; Yang, Xiong-Li; Wang, Zhongfeng

    2016-01-01

    In the inner retina, ganglion cells (RGCs) integrate and process excitatory signal from bipolar cells (BCs) and inhibitory signal from amacrine cells (ACs). Using multiple labeling immunohistochemistry, we first revealed the expression of the cannabinoid CB1 receptor (CB1R) at the terminals of ACs and BCs in rat retina. By patch-clamp techniques, we then showed how the activation of this receptor dichotomously regulated miniature inhibitory postsynaptic currents (mIPSCs), mediated by GABAA receptors and glycine receptors, and miniature excitatory postsynaptic currents (mEPSCs), mediated by AMPA receptors, of RGCs in rat retinal slices. WIN55212-2 (WIN), a CB1R agonist, reduced the mIPSC frequency due to an inhibition of L-type Ca(2+) channels no matter whether AMPA receptors were blocked. In contrast, WIN reduced the mEPSC frequency by suppressing T-type Ca(2+) channels only when inhibitory inputs to RGCs were present, which could be in part due to less T-type Ca(2+) channels of cone BCs, presynaptic to RGCs, being in an inactivation state under such condition. This unique feature of CB1R-mediated retrograde regulation provides a novel mechanism for modulating excitatory synaptic transmission in the inner retina. Moreover, depolarization of RGCs suppressed mIPSCs of these cells, an effect that was eliminated by the CB1R antagonist SR141716, suggesting that endocannabinoid is indeed released from RGCs.

  15. 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.

  16. DAPI diffusion after intravitreal injection of mesenchymal stem cells in the injured retina of rats.

    Science.gov (United States)

    Castanheira, Paula; Torquetti, Leonardo Torquetti; Magalhãs, Débora Rodrigues Soares; Nehemy, Marcio B; Goes, Alfredo M

    2009-01-01

    To evaluate DAPI (4',6-diamidino-2-phenylindole) as a nuclear tracer of stem cell migration and incorporation it was observed the pattern of retinal integration and differentiation of mesenchymal stem cells (MSCs) injected into the vitreous cavity of rat eyes with retinal injury. For this purpose adult rat retinas were submitted to laser damage followed by transplantation of DAPI-labeled BM-MSCs grafts and double-labeled DAPI and quantum dot-labeled BM-MSCs. To assess a possible DAPI diffusion as well as the integration and differentiation of DAPI-labeled BM-MSCs in laser-injured retina, host retinas were evaluated 8 weeks after injury/transplantation. It was demonstrated that, 8 weeks after the transplant, most of the retinal cells in all neural retinal presented nuclear DAPI labeling, specifically in the outer nuclear layer (ONL), inner nuclear layer (INL), and ganglion cell layer (GCL). Meanwhile, at this point, most of the double-labeled BM-MSCs (DAPI and quantum dot) remained in the vitreous cavity and no retinal cells presented the quantum dot marker. Based on these evidences we concluded that DAPI diffused to adjacent retinal cells while the nanocrystals remained labeling only the transplanted BM-MSCs. Therefore, DAPI is not a useful marker for stem cells in vivo tracing experiments because the DAPI released from dying cells in moment of the transplant are taken up by host cells in the tissue.

  17. The scotopic electroretinogram of the sugar glider related to histological features of its retina.

    Science.gov (United States)

    Akula, James D; Esdaille, Tricia M; Caffé, A Romeo; Naarendorp, Franklin

    2011-11-01

    The flash electroretinogram (ERG) was used to characterize the scotopic retinal function in a marsupial. Key parameter values of the a- and b-waves of adult male sugar gliders, Petaurus breviceps breviceps, elicited with ganzfeld flashes were determined under dark- and light-adapted conditions. Using standard histological methods, the thicknesses of the major layers of the retina were assessed to provide insight into the nature of the ERG responses. The ERG and histological results were compared to corresponding data for placental C57Bl/6 mice to establish whether the functional retinal specialization that underlies scotopic visual function in a marsupial parallels that of a placental mouse. The sensitivity of the a-wave assessed with the Lamb and Pugh (Invest Ophthalmol Vis Sci 47:5138-5152, 2006) "model" and that of the b-wave assessed with standard methods were lower in the sugar glider compared to the mouse. The thickness of the sugar glider retina was two-third of that of the mouse. The high-intensity flash ERG of the sugar glider substantially differed in shape from that of the mouse reflecting perhaps structural and functional differences between the two species at the level of the inner retina.

  18. Cell type-specific bipolar cell input to ganglion cells in the mouse retina.

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    Neumann, S; Hüser, L; Ondreka, K; Auler, N; Haverkamp, S

    2016-03-01

    Many distinct ganglion cell types, which are the output elements of the retina, were found to encode for specific features of a visual scene such as contrast, color information or movement. The detailed composition of retinal circuits leading to this tuning of retinal ganglion cells, however, is apart from some prominent examples, largely unknown. Here we aimed to investigate if ganglion cell types in the mouse retina receive selective input from specific bipolar cell types or if they sample their synaptic input non-selectively from all bipolar cell types stratifying within their dendritic tree. To address this question we took an anatomical approach and immunolabeled retinae of two transgenic mouse lines (GFP-O and JAM-B) with markers for ribbon synapses and type 2 bipolar cells. We morphologically identified all green fluorescent protein (GFP)-expressing ganglion cell types, which co-stratified with type 2 bipolar cells and assessed the total number of bipolar input synapses and the proportion of synapses deriving from type 2 bipolar cells. Only JAM-B ganglion cells received synaptic input preferentially from bipolar cell types other than type 2 bipolar cells whereas the other analyzed ganglion cell types sampled their bipolar input most likely from all bipolar cell terminals within their dendritic arbor.

  19. Melanopsin and the Non-visual Photochemistry in the Inner Retina of Vertebrates.

    Science.gov (United States)

    Díaz, Nicolás M; Morera, Luis P; Guido, Mario E

    2016-01-01

    Melanopsin (Opn4), a member of the G-protein-coupled receptor family, is a vitamin A-based opsin in the vertebrate retina that has been shown to be involved in the synchronization of circadian rhythms, pupillary light reflexes, melatonin suppression and other light-regulated tasks. In nonmammalian vertebrates there are two Opn4 genes, Opn4m and Opn4x, the mammalian and Xenopus orthologs respectively. Opn4x is only expressed in nonmammalian vertebrates including reptiles, fish and birds, while Opn4m is found in a subset of retinal ganglion cells (RGCs), the intrinsically photosensitive (ip) RGCs of the inner retina of both mammals and nonmammalian vertebrates. All opsins described utilize retinaldehyde as chromophore, photoisomerized from 11-cis- to all-trans-retinal upon light exposure. Visual retinal photoreceptor cones and rods, responsible for day and night vision respectively, recycle retinoids through a process called the visual cycle that involves the retinal pigment epithelium or glial Müller cells. Although Opn4 has been characterized as a bistable photopigment, little is known about the mechanism/s involved in its chromophore regeneration. In this review, we will attempt to shed light on the visual cycle taking place in the inner retina and discuss the state of the art in the nonvisual photochemistry of vertebrates.

  20. Folate antagonist, methotrexate induces neuronal differentiation of human embryonic stem cells transplanted into nude mouse retina.

    Science.gov (United States)

    Hara, Akira; Taguchi, Ayako; Aoki, Hitomi; Hatano, Yuichiro; Niwa, Masayuki; Yamada, Yasuhiro; Kunisada, Takahiro

    2010-06-25

    Transplanted embryonic stem (ES) cells can be integrated into the retinas of adult mice as well-differentiated neuroretinal cells. However, the transplanted ES cells also have a tumorigenic activity as they have the ability for multipotent differentiation to various types of tissues. In the present study, human ES (hES) cells were transplanted into adult nude mouse retinas by intravitreal injections 20 h after intravitreal N-methyl-D-aspartate (NMDA) administration. After the transplantation of hES cells, the folate antagonist, methotrexate (MTX) was administrated in order to control the differentiation of the transplanted hES cells. Neuronal differentiation and teratogenic potential of hES cells were examined immunohistochemically 5 weeks after transplantation. The proliferative activity of transplanted cells was determined by both the mitotic index and the Ki-67 proliferative index. Disappearance of Oct-4-positive hES cells showing undifferentiated morphology was observed after intraperitoneal MTX treatment daily, for 15 days. Decreased mitotic and Ki-67 proliferative indices, and increased neuronal differentiation were detected in the surviving hES cells after the MTX treatment. These results suggest two important effects of intraperitoneal MTX treatment for hES cells transplanted into nude mouse retina: (1) MTX treatment following transplantation induces neuronal differentiation, and (2) MTX decreases proliferative activity and tumorigenic potential.

  1. β-Catenin inactivation is a pre-requisite for chick retina regeneration.

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    Jie Zhu

    Full Text Available In the present study we explored the role of β-catenin in mediating chick retina regeneration. The chick can regenerate its retina by activating stem/progenitor cells present in the ciliary margin (CM of the eye or via transdifferentiation of the retinal pigmented epithelium (RPE. Both modes require fibroblast growth factor 2 (FGF2. We observed, by immunohistochemistry, dynamic changes of nuclear β-catenin in the CM and RPE after injury (retinectomy. β-Catenin nuclear accumulation was transiently lost in cells of the CM in response to injury alone, while the loss of nuclear β-catenin was maintained as long as FGF2 was present. However, nuclear β-catenin positive cells remained in the RPE in response to injury and were BrdU-/p27+, suggesting that nuclear β-catenin prevents those cells from entering the cell cycle. If FGF2 is present, the RPE undergoes dedifferentiation and proliferation concomitant with loss of nuclear β-catenin. Moreover, retinectomy followed by disruption of active β-catenin by using a signaling inhibitor (XAV939 or over-expressing a dominant negative form of Lef-1 induces regeneration from both the CM and RPE in the absence of FGF2. Our results imply that β-catenin protects cells of the CM and RPE from entering the cell cycle in the developing eye, and specifically for the RPE during injury. Thus inactivation of β-catenin is a pre-requisite for chick retina regeneration.

  2. 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.

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

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    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.

  4. 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.

  5. The cancer-retina antigen recoverin as a potential biomarker for renal tumors.

    Science.gov (United States)

    Golovastova, Marina O; Tsoy, Larisa V; Bocharnikova, Anna V; Korolev, Dmitry O; Gancharova, Olga S; Alekseeva, Ekaterina A; Kuznetsova, Ekaterina B; Savvateeva, Lyudmila V; Skorikova, Elena E; Strelnikov, Vladimir V; Varshavsky, Vladimir A; Vinarov, Andrey Z; Nikolenko, Vladimir N; Glybochko, Peter V; Zernii, Evgeni Yu; Zamyatnin, Andrey A; Bazhin, Alexandr V; Philippov, Pavel P

    2016-07-01

    The renal cell carcinoma is the ninth most common cancer with an increasing occurrence and mortality. Recoverin is the first retina-specific photoreceptor protein that was shown to undergo aberrant expression, due to its promoter demethylation, as a cancer-retina antigen in a number of malignant tumors. In this work, we demonstrated that recoverin is indeed expressed in 68.4 % of patients with different subtypes of renal cell carcinoma, and this expression has tendency to correlate with tumor size. Interestingly, 91.7 % of patients with the benign renal tumor, oncocytoma, express recoverin as well in their tumor. Epigenetic analysis of the recoverin gene promoter revealed a stable mosaic methylation pattern with the predominance of the methylated state, with the exception of -80 and 56 CpG dinucleotides (CpGs). While the recoverin expression does not correlate withoverall survival of the tumor patients, the methylation of the recoverin gene promoter at -80 position is associated with better overall survival of the patients. This work is the first report pointing towards the association of overall survival of renal cell carcinoma (RCC) patients with promoter methylation of a cancer-retina antigen. Taken together, these data allow to consider recoverin as a potential therapeutic target and/or marker for renal tumors.

  6. The in vitro protective effect of alpha-tocopherol on oxidative injury in the dog retina.

    Science.gov (United States)

    Zapata, G L; Guajardo, M H; Terrasa, A M

    2008-08-01

    Oxidative stress is a risk factor for eye diseases. Free radicals elicited during the inflammatory process often lead to oxidative damage of lipids (lipid peroxidation). The retina is highly vulnerable because of its high content of polyunsaturated fatty acids (PUFAs). The aim of this study was to investigate in vitro the effect of alpha-tocopherol on the Fe(2+)-ascorbate induced lipid peroxidation in the canine retina. Lipid peroxidation of retinal homogenates was carried out with and without the addition of alpha-tocopherol and monitored both by chemiluminescence and production of thiobarbituric acid reactive substances (TBARS). Total chemiluminescence counts per minute was lower in those homogenates pre-incubated with alpha-tocopherol. Thus, with 1 micromol alpha-tocopherol/mg of protein, 100% inhibition of chemiluminescence and a decrease of TBARS content from 20.46+/-0.85 to 2.62+/-2.77 nmol/mg protein were observed. Simultaneously, changes produced by oxidative stress were noted in the fatty acid composition of retinal lipids. Docosahexaenoic acid was decreased from 14.33+/-2.32% to 1.84+/-0.14% after peroxidation, but this fatty acid remained unaltered in the presence of 1 micromol alpha-tocopherol. These results show that under these experimental conditions, alpha-tocopherol may act as anti-oxidant protecting retinal membranes from deleterious effects. Further studies are required to assess its use in free radical generating conditions affecting the canine retina.

  7. Effects of Fenofibrate on Adiponectin Expression in Retinas of Streptozotocin-Induced Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Ying-Jung Hsu

    2014-01-01

    Full Text Available Adiponectin has been associated with increased risks of microvascular complications in diabetes; however, its role in the development of diabetic retinopathy (DR is unknown. Fenofibrate is a lipid-lowering agent that has been shown to be capable of preventing DR progression. We investigated the expression of adiponectin and its receptors in DR and evaluated the effects of fenofibrate on their expression. The mRNA and protein levels of adiponectin and its receptors were elevated in retinas of streptozotocin-induced diabetic rats and were suppressed following fenofibrate treatment. Immunofluorescence staining demonstrated that adiponectin and adipoR1 were expressed in cells located within blood vessels, the retinal ganglion, and the inner nuclear layer. AdipoR1 was strongly expressed whereas adipoR2 was only weekly expressed in vascular endothelial cells. The in vitro experiments showed that adiponectin expression was induced by high glucose concentrations in RGC-5 and RAW264.7 cells and was suppressed following fenofibrate treatment. AdipoR1 and adipoR2 levels in RGC-5 cells were elevated in high glucose concentrations and suppressed by fenofibrate. Our results demonstrated that adiponectin may be a proinflammatory mediator in diabetic retinas and fenofibrate appears to modulate the expression of adiponectin and its receptors in diabetic retinas, effectively reducing DR progression.

  8. Transforming growth factor-beta (TGF-beta) and programmed cell death in the vertebrate retina.

    Science.gov (United States)

    Duenker, Nicole

    2005-01-01

    Programmed cell death (PCD) is a precisely regulated phenomenon essential for the homeostasis of multicellular organisms. Developmental systems, particularly the nervous system, have provided key observations supporting the physiological role of PCD. We have recently shown that transforming growth factor-beta (TGF-beta) plays an important role in mediating ontogenetic PCD in the nervous system. As part of the central nervous system the developing retina serves as an ideal model system for investigating apoptotic processes during neurogenesis in vivo as it is easily accessible experimentally and less complex due to its limited number of different neurons. This review summarizes data indicating a pivotal role of TGF-beta in mediating PCD in the vertebrate retina. The following topics are discussed: expression of TGF-beta isoforms and receptors in the vertebrate retina, the TGF-beta signaling pathway, functions and molecular mechanisms of PCD in the nervous system, TGF-beta-mediated retinal apoptosis in vitro and in vivo, and interactions of TGF-beta with other pro- and anti-apoptotic factors.

  9. Wavefront sensorless approaches to adaptive optics for in vivo fluorescence imaging of mouse retina

    Science.gov (United States)

    Wahl, Daniel J.; Bonora, Stefano; Mata, Oscar S.; Haunerland, Bengt K.; Zawadzki, Robert J.; Sarunic, Marinko V.; Jian, Yifan

    2016-03-01

    Adaptive optics (AO) is necessary to correct aberrations when imaging the mouse eye with high numerical aperture. In order to obtain cellular resolution, we have implemented wavefront sensorless adaptive optics for in vivo fluorescence imaging of mouse retina. Our approach includes a lens-based system and MEMS deformable mirror for aberration correction. The AO system was constructed with a reflectance channel for structural images and fluorescence channel for functional images. The structural imaging was used in real-time for navigation on the retina using landmarks such as blood vessels. We have also implemented a tunable liquid lens to select the retinal layer of interest at which to perform the optimization. At the desired location on the mouse retina, the optimization algorithm used the fluorescence image data to drive a modal hill-climbing algorithm using an intensity or sharpness image quality metric. The optimization requires ~30 seconds to complete a search up to the 20th Zernike mode. In this report, we have demonstrated the AO performance for high-resolution images of the capillaries in a fluorescence angiography. We have also made progress on an approach to AO with pupil segmentation as a possible sensorless technique suitable for small animal retinal imaging. Pupil segmentation AO was implemented on the same ophthalmic system and imaging performance was demonstrated on fluorescent beads with induced aberrations.

  10. Imaging pulse wave velocity in mouse retina using swept-source OCT (Conference Presentation)

    Science.gov (United States)

    Song, Shaozhen; Wei, Wei; Wang, Ruikang K.

    2016-03-01

    Blood vessel dynamics has been a significant subject in cardiology and internal medicine, and pulse wave velocity (PWV) on artery vessels is a classic evaluation of arterial distensibility, and has never been ascertained as a cardiovascular risk marker. The aim of this study is to develop a high speed imaging technique to capture the pulsatile motion on mouse retina arteries with the ability to quantify PWV on any arterial vessels. We demonstrate a new non-invasive method to assess the vessel dynamics on mouse retina. A Swept-source optical coherence tomography (SS-OCT) system is used for imaging micro-scale blood vessel motion. The phase-stabilized SS-OCT provides a typical displacement sensitivity of 20 nm. The frame rate of imaging is ~16 kHz, at A-line rate of ~1.62 MHz, which allows the detection of transient pulse waves with adequate temporal resolution. Imaging volumes with repeated B-scans are obtained on mouse retina capillary bed, and the mouse oxymeter signal is recorded simultaneously. The pulse wave on artery and vein are resolved, and with the synchronized heart beat signal, the temporal delay on different vessel locations is determined. The vessel specific measurement of PWV is achieved for the first time with SS-OCT, for pulse waves propagating more than 100 cm/s. Using the novel methodology of retinal PWV assessment, it is hoped that the clinical OCT scans can provide extended diagnostic information of cardiology functionalities.

  11. Knockout of Ccr2 alleviates photoreceptor cell death in rodent retina exposed to chronic blue light.

    Science.gov (United States)

    Hu, Zizhong; Zhang, Yi; Wang, Junling; Mao, Pingan; Lv, Xuehua; Yuan, Songtao; Huang, Zhengru; Ding, Yuzhi; Xie, Ping; Liu, Qinghuai

    2016-11-10

    Age-related macular degeneration (AMD), the leading cause of visual loss after the age of 60 years, is a degenerative retinal disease involving a variety of environmental and hereditary factors. Although it has been implicated that immune system is involved in the disease progression, the exact role that microglia has is still unclear. Here we demonstrated that knockout of Ccr2 gene could alleviate photoreceptor cell death in mice retinas exposed to chronic blue light. In Ccr2(-/-) mice, a damaged microglia recruitment was shown in retina and this could protect the visual function in electroretinogram and alleviate the photoreceptor apoptosis, which thus helped attenuate the blue light-induced retinopathy. We further found an increased co-location of NLRP3, Iba-1, and IL-1β in fluorescence and a concomitant increased protein expression of NLRP3, caspase-1, and IL-1β in western blotting in chronic blue light-induced retinopathy. Moreover, the activation of microglia and their cellular NLRP3 inflammasomes occurred as an earlier step before the structural and functional damage of the mice retinas, which collectively supported that microglial NLRP3 inflammasome might be the key to the chronic blue light-induced retinopathy.

  12. Rotenone induces degeneration of photoreceptors and impairs the dopaminergic system in the rat retina.

    Science.gov (United States)

    Esteve-Rudd, Julián; Fernández-Sánchez, Laura; Lax, Pedro; De Juan, Emilio; Martín-Nieto, José; Cuenca, Nicolás

    2011-10-01

    Rotenone is a widely used pesticide and a potent inhibitor of mitochondrial complex I (NADH-quinone reductase) that elicits the degeneration of dopaminergic neurons and thereby the appearance of a parkinsonian syndrome. Here we have addressed the alterations induced by rotenone at the functional, morphological and molecular levels in the retina, including those involving both dopaminergic and non-dopaminergic retinal neurons. Rotenone-treated rats showed abnormalities in equilibrium, postural instability and involuntary movements. In their outer retina we observed a loss of photoreceptors, and a reduced synaptic connectivity between those remaining and their postsynaptic neurons. A dramatic loss of mitochondria was observed in the inner segments, as well as in the axon terminals of photoreceptors. In the inner retina we observed a decrease in the expression of dopaminergic cell molecular markers, including loss of tyrosine hydroxylase immunoreactivity, associated with a reduction of the dopaminergic plexus and cell bodies. An increase in immunoreactivity of AII amacrine cells for parvalbumin, a Ca(2+)-scavenging protein, was also detected. These abnormalities were accompanied by a decrease in the amplitude of scotopic and photopic a- and b-waves and an increase in the b-wave implicit time, as well as by a lower amplitude and greater latency in oscillatory potentials. These results indicate that rotenone induces loss of vision by promoting photoreceptor cell death and impairment of the dopaminergic retinal system.

  13. Gene transfer to the nonhuman primate retina with recombinant feline immunodeficiency virus vectors.

    Science.gov (United States)

    Lotery, Andrew J; Derksen, Todd A; Russell, Stephen R; Mullins, Robert F; Sauter, Sybille; Affatigato, Louisa M; Stone, Edwin M; Davidson, Beverly L

    2002-04-10

    We hypothesize that recombinant feline immunodeficiency viral (rFIV) vectors may be useful for gene transfer to the nonhuman primate retina. We performed vitrectomies and subretinal injections in the right eyes of 11 cynomolgus monkeys. Vesicular stomatitis virus glycoprotein-pseudotyped rFIV that expressed the Escherichia coli beta-galactosidase gene was injected into eight eyes. Sham vehicle or lactose buffer injections were also performed in two of these eight study eyes. rFIV pseudotyped with an amphotropic envelope was used in two eyes, and in one animal injections of lactose buffer only were given. After surgery the animals were clinically evaluated by retinal photography and electroretinography. beta-Galactosidase expression was evaluated, at a final end point, in histological sections. We found photoreceptor and Müller cells to have the greatest transgene expression. Focal inflammatory responses localized to the injection site were seen histologically in all eyes. No difference in transduction efficiency was seen between injections near the macula and more peripheral injections. Visual function as assessed by electroretinography was not significantly affected by vector or vehicle injections. We conclude that rFIV vectors administered beneath the retina can transduce a variety of retinal cells in the nonhuman primate retina. rFIV vectors have therapeutic potential and could be exploited to develop gene therapy for the human eye.

  14. Special characteristics of the transcription and splicing machinery in photoreceptor cells of the mammalian retina.

    Science.gov (United States)

    Derlig, Kristin; Giessl, Andreas; Brandstätter, Johann Helmut; Enz, Ralf; Dahlhaus, Regina

    2015-11-01

    Chromatin organization and the management of transcription and splicing are fundamental to the correct functioning of every cell but, in particular, for highly active cells such as photoreceptors, the sensory neurons of the retina. Rod photoreceptor cells of nocturnal animals have recently been shown to have an inverted chromatin architecture compared with rod photoreceptor cells of diurnal animals. The heterochromatin is concentrated in the center of the nucleus, whereas the genetically active euchromatin is positioned close to the nuclear membrane. This unique chromatin architecture suggests that the transcription and splicing machinery is also subject to specific adaptations in these cells. Recently, we described the protein Simiate, which is enriched in nuclear speckles and seems to be involved in transcription and splicing processes. Here, we examine the distribution of Simiate and nuclear speckles in neurons of mouse retinae. In retinal neurons of the inner nuclear and ganglion cell layer, Simiate is concentrated in a clustered pattern in the nuclear interior, whereas in rod and cone photoreceptor cells, Simiate is present at the nuclear periphery. Further staining with markers for the transcription and splicing machinery has confirmed the localization of nuclear speckle components at the periphery. Comparing the distribution of nuclear speckles in retinae of the nocturnal mouse with the diurnal degu, we found no differences in the arrangement of the transcription and splicing machinery in their photoreceptor cells, thus suggesting that the organization of these machineries is not related to the animal's lifestyle but rather represents a general characteristic of photoreceptor organization and function.

  15. Changes in metabolic proteins in ex vivo rat retina during glutamate-induced neural progenitor cell induction.

    Science.gov (United States)

    Tokuda, Kazuhiro; Kuramitsu, Yasuhiro; Baron, Byron; Kitagawa, Takao; Tokuda, Nobuko; Kobayashi, Masaaki; Kimura, Kazuhiro; Sonoda, Koh-Hei; Nakamura, Kazuyuki

    2016-08-01

    Understanding how energy metabolism and related proteins influence neural progenitor cells in adult tissues is critical for developing new strategies in clinical tissue regeneration therapy. We have recently reported that a subtoxic concentration of glutamate-induced neural progenitor cells in the mature ex vivo rat retina. We herein explore changes in the metabolic pathways during the process. We firstly observed an increase in lactate and lactate dehydrogenase concentration in the glutamate-treated retina. We then investigated the levels of glycolytic enzymes and confirmed significant upregulation of pyruvate kinase M type (PKM), especially PKM2, enolase, phosphoglycerate mutase 1 (PGAM1), and inosine-5'-monophosphate dehydrogenase (IMPDH1) in the glutamate-treated retina compared to the untreated retina. An analysis of the subcellular localization of PKM2 revealed nuclear translocation in the treated retina, which has been reported to regulate cell cycle proliferation and glycolytic enzymes. Our findings indicate that the mature rat retina undergoes an increase in aerobic glycolysis. PKM2, both in the cytoplasm and in the nucleus, may thus play an important role during neural progenitor cell induction, as it does in other proliferating cells.

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

    Directory of Open Access Journals (Sweden)

    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.

  17. 共焦显微镜诊断双眼角膜塑型镜相关性阿米巴角膜炎1例%Diagnosis of bilateral acanthamoeba keratitis related to orthokeratology with Heidelberg Retina Yomograph Ⅲ-RCM

    Institute of Scientific and Technical Information of China (English)

    张琛; 孙旭光

    2007-01-01

    患者,男性,20岁,学生,因过夜配戴角膜塑型镜后出现双眼红、疼痛、视力下降半个月,于2006年12月5日来我院就诊。患者为华裔加拿大人,半年前来北京读书,配戴角膜塑型镜已4年,每天用护理液清洗镜片前均用自来水清洗。来我国后护理方式没有改变。

  18. The effects of the apoE4 genotype on the developing mouse retina.

    Science.gov (United States)

    Maharshak, Idit; Salomon-Zimri, Shiran; Antes, Ran; Liraz, Ori; Nisgav, Yael; Livnat, Tami; Weinberger, Dov; Colton, Carol A; Solomon, Arieh S; Michaelson, Daniel M

    2016-04-01

    Apolipoprotein E4 (apoE4), the most prevalent genetic risk factor for Alzheimer's disease (AD), is associated with neuronal and vascular impairments. The retina, which is as an extension of the central nervous system (CNS), is a particularly suitable model for studying developmental and functional aspects of the neuronal and vascular systems. This study investigates the apoE4-dependent developmental effects on the retinal vasculature and neuronal systems and on the levels of apoE and the vascular endothelial growth factor (VEGF) in the retina. This was performed utilizing retinas of 4, 7, 12, and of 120-day-old human-apoE4-targeted replacement mice and of corresponding mice that express the AD benign isoform, apoE3. The results obtained revealed retinal vascular pathology in the apoE4 mice, which started on the early post-natal days. This includes transient increase in vascular branching, and vascular buds which are round vascular elements representing sprouting or retracting vessels. These effects peaked and ended during the neonatal period. Examination of the synaptic system utilizing the pre-synaptic marker synaptophysin revealed a significant decrease of retinal synaptic density in the apoE4 mice, which was detectable by post-natal day 12 (P12). These morphological changes are associated with neonatal age-dependent elevation in the apoE levels in both apoE3 and apoE4 retinas which is more profound in the apoE4 mice and a corresponding increase in VEGF levels, which is less profound in the apoE4 mice. Additionally, we observed lower levels of retinal VEGF in the apoE4 mice compared to the apoE3 mice retinas on P12. These results show that apoE4 has a transient vascular effect during retinal development that ends in the neonatal period, which is accompanied by a synaptic effect that begins at the end of the neonatal period. These findings show that the apoE4 genotype can have distinct developmental effects on both the retinal vasculature and on neurons and

  19. 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

  20. Clinical, electroretinographic and histomorphometric evaluation of the retina in sheep with natural scrapie

    Directory of Open Access Journals (Sweden)

    Toutain Pierre-Louis

    2011-06-01

    Full Text Available Abstract Background The retina is part of the diencephalon in a peripheral location and may be involved in prion diseases. Retinal function and structural changes were assessed in naturally scrapie-affected red face Manech ewes presenting the classical signs of the disease, and clinically healthy age-matched subjects for controls. Ophthalmic examination was done prior to electroretinography (ERG, which was carried out under conditions that allowed photopic and scotopic activities to be assessed. Histomorphometry of the inner and outer retinal layers was performed post-mortem, and retinas were also examined for evidence of abnormal prion protein (PrPSc accumulation and glial fibrillary acidic protein (GFAP upregulation as a marker of gliosis. Scrapie status was determined by examination of brain tissue Results Ocular reflexes and ophthalmoscopy did not reveal any difference between scrapie affected and control animals. Although the light-and dark-adapted ERG responses of both rod-and cone-mediated functions had a similar waveform in scrapie-affected and control sheep, a significant reduction in the amplitude of the ERG a-and b-waves was observed in affected animals compared to controls. These functional alterations were correlated with a substantial loss of cells in the outer nuclear layer (ONL, lengthening and disorganization in photoreceptor segments, and substantial reduction in cellularity and thickness of the inner nuclear layer (INL. The degenerative changes in the INL and ONL were most marked in the central and paracentral areas of the scrapie retinas, and were accompanied in all scrapie retinas by PrPSc deposition in the ganglion cell and synaptic layers. GFAP immunoreactivity was mainly increased in the ganglion cell and inner plexiform layers. Conclusions No appreciable fundoscopic changes were observed in the scrapie-affected ewes although reproducible changes in retinal function as measured by ERG were observed in these animals. The

  1. Characterization of the retina in the alpha7 nicotinic acetylcholine receptor knockout mouse

    Science.gov (United States)

    Smith, Marci L.

    Acetylcholine receptors (AChRs) are involved in visual processing and are expressed by inner retinal neurons in all species studied to date (Keyser et al., 2000; Dmitrieva et al., 2007; Liu et al., 2009), but their distribution in the mouse retina remains unknown. Reductions in alpha7 nicotinic AChRs (nAChRs) are thought to contribute to memory and visual deficits observed in Alzheimer's and schizophrenia (Coyle et al., 1983; Nordberg et al., 1999; Leonard et al., 2006). However, the alpha7 nAChR knockout (KO) mouse has a mild phenotype (Paylor et al., 1998; Fernandes et al., 2006; Young et al., 2007; Origlia et al., 2012). The purpose of this study was to determine the expression of AChRs in wildtype (WT) mouse retina and to assess whether up-regulation of other AChRs in the alpha7 nAChR KO retina may explain the minimal deficits described in the KO mouse. Reverse-transcriptase PCR (RT-PCR) showed that mRNA transcripts for alpha2-7, alpha 9, alpha10, beta2-4 nAChR subunits and m1-m5 muscarinic AChR (mAChR) subtypes were present in WT murine retina. Western blot analysis confirmed the presence of alpha3-5, alpha9, and m1-m5 AChR proteins and immunohistochemical analysis demonstrated nAChR and mAChR proteins expressed by subsets of bipolar, amacrine and ganglion cells. This is the first reported expression of alpha9 and alpha10 nAChR transcripts and alpha9 nAChR proteins in the retina of any species. Quantitative RT-PCR (qPCR) showed changes in AChR transcript expression in the alpha7 nAChR KO mouse retina relative to WT. Within whole retina alpha2, alpha9, alpha10, beta4, m1 and m4 AChR transcripts were up-regulated, while alpha5 nAChR transcripts were down-regulated. However, cell populations showed subtle differences; m4 mAChR transcripts were up-regulated in the ganglion cell layer and outer portion of the inner nuclear layer (oINL),while beta4 nAChR transcript up-regulation was limited to the oINL. Surprisingly, alpha2, alpha9, beta4, m2 and m4 transcripts were

  2. Expressions of visual pigments and synaptic proteins in neonatal chick retina exposed to light of variable photoperiods

    Indian Academy of Sciences (India)

    KUMAR ABHIRAM JHA; TAPAS C NAG; SHASHI WADHWA; TARA SANKAR ROY

    2016-12-01

    Light causes damage to the retina, which is one of the supposed factors for age-related macular degeneration inhuman. Some animal species show drastic retinal changes when exposed to intense light (e.g. albino rats). Althoughbirds have a pigmented retina, few reports indicated its susceptibility to light damage. To know how light influences acone-dominated retina (as is the case with human), we examined the effects of moderate light intensity on the retina ofwhite Leghorn chicks (Gallus g. domesticus). The newly hatched chicks were initially acclimatized at 500 lux for 7days in 12 h light: 12 h dark cycles (12L:12D). From posthatch day (PH) 8 until PH 30, they were exposed to 2000 luxat 12L:12D, 18L:6D (prolonged light) and 24L:0D (constant light) conditions. The retinas were processed fortransmission electron microscopy and the level of expressions of rhodopsin, S- and L/M cone opsins, and synapticproteins (Synaptophysin and PSD-95) were determined by immunohistochemistry and Western blotting. Rearing in24L:0D condition caused disorganization of photoreceptor outer segments. Consequently, there were significantlydecreased expressions of opsins and synaptic proteins, compared to those seen in 12L:12D and 18L:6D conditions.Also, there were ultrastructural changes in outer and inner plexiform layer (OPL, IPL) of the retinas exposed to24L:0D condition. Our data indicate that the cone-dominated chick retina is affected in constant light condition, withchanges (decreased) in opsin levels. Also, photoreceptor alterations lead to an overall decrease in synaptic proteinexpressions in OPL and IPL and death of degenerated axonal processes in IPL.

  3. Selective over-expression of endothelin-1 in endothelial cells exacerbates inner retinal edema and neuronal death in ischemic retina.

    Directory of Open Access Journals (Sweden)

    Simon S F Cheung

    Full Text Available The level of endothelin-1 (ET-1, a potent vasoconstrictor, was associated with retinopathy under ischemia. The effects of endothelial endothelin-1 (ET-1 over-expression in a transgenic mouse model using Tie-1 promoter (TET-1 mice on pathophysiological changes of retinal ischemia were investigated by intraluminal insertion of a microfilament up to middle cerebral artery (MCA to transiently block the ophthalmic artery. Two-hour occlusion and twenty-two-hour reperfusion were performed in homozygous (Hm TET-1 mice and their non-transgenic (NTg littermates. Presence of pyknotic nuclei in ganglion cell layer (GCL was investigated in paraffin sections of ipsilateral (ischemic and contralateral (non-ischemic retinae, followed by measurement of the thickness of inner retinal layer. Moreover, immunocytochemistry of glial fibrillary acidic protein (GFAP, glutamine synthetase (GS and aquaporin-4 (AQP4 peptides on retinal sections were performed to study glial cell reactivity, glutamate metabolism and water accumulation, respectively after retinal ischemia. Similar morphology was observed in the contralateral retinae of NTg and Hm TET-1 mice, whereas ipsilateral retina of NTg mice showed slight structural and cellular changes compared with the corresponding contralateral retina. Ipsilateral retinae of Hm TET-1 mice showed more significant changes when compared with ipsilateral retina of NTg mice, including more prominent cell death in GCL characterized by the presence of pyknotic nuclei, elevated GS immunoreactivity in Müller cell bodies and processes, increased AQP-4 immunoreactivity in Müller cell processes, and increased inner retinal thickness. Thus, over-expression of endothelial ET-1 in TET-1 mice may contribute to increased glutamate-induced neurotoxicity on neuronal cells and water accumulation in inner retina leading to edema.

  4. Glucocorticoid receptors in the retina, Müller glia and the formation of Müller glia-derived progenitors.

    Science.gov (United States)

    Gallina, Donika; Zelinka, Christopher; Fischer, Andy J

    2014-09-01

    Identification of the signaling pathways that influence the reprogramming of Müller glia into neurogenic retinal progenitors is key to harnessing the potential of these cells to regenerate the retina. Glucocorticoid receptor (GCR) signaling is commonly associated with anti-inflammatory responses and GCR agonists are widely used to treat inflammatory diseases of the eye, even though the cellular targets and mechanisms of action in the retina are not well understood. We find that signaling through GCR has a significant impact upon the ability of Müller glia to become proliferating Müller glia-derived progenitor cells (MGPCs). The primary amino acid sequence and pattern of GCR expression in the retina is highly conserved across vertebrate species, including chickens, mice, guinea pigs, dogs and humans. In all of these species we find GCR expressed by the Müller glia. In the chick retina, we find that GCR is expressed by progenitors in the circumferential marginal zone (CMZ) and is upregulated by Müller glia in acutely damaged retinas. Activation of GCR signaling inhibits the formation of MGPCs and antagonizes FGF2/MAPK signaling in the Müller glia. By contrast, we find that inhibition of GCR signaling stimulates the formation of proliferating MGPCs in damaged retinas, and enhances the neuronal differentiation while diminishing glial differentiation. Given the conserved expression pattern of GCR in different vertebrate retinas, we propose that the functions and mechanisms of GCR signaling are highly conserved and are mediated through the Müller glia. We conclude that GCR signaling directly inhibits the formation of MGPCs, at least in part, by interfering with FGF2/MAPK signaling.

  5. Expression and localization of inwardly rectifying potassium channel Kit2.1 in glia cells of native bovine retina

    Institute of Scientific and Technical Information of China (English)

    PAN Ai-hua; LUO Xue-gang

    2005-01-01

    Objective The purpose of this study is to identify the molecular basis of the contacting -neuron membrane K+ conductance in glia cells of native bovine retina. Methods RT-PCR, Northern blot and Western blot analyses were used to detect the expression of the inwardly rectifying K+ (Kir) channel subunits Kir2.1 in native bovine RPE and neural retina. The distribution of Kir2.1 protein was determined in frozen sections of bovine retina-RPEchoroid by indirect immunofluorescence analysis. Results RT-PCR analysis reveals Kir2.1 transcript in both RPE and neural retina. In Northern blots, Kir2.1 probe hybridizes to an appropriately sized-transcript in neural retina but not in RPE. In Western blots, Kir2.1 antibody recognizes a major monomer of about 60 kDa in neural retina but not in RPE. Immunofluorescence reveals that Kir2.1 immunostaining is expressed at many parts of Muller cells, especially in the membrane domains of Muller cells that contact retinal neurons, i. e. , along the two stem processes,over the soma, and in the side branches extending into the synaptic layers. No immunostaining is seen in RPE. Doubling staining shows that Kir2.1 proteins and glutamine synthetase proteins which are a marker of Muller cell co-localized well. Conclusions These results reveal that Kir2.1 is localized in the Muller cells, no Kir2.1 in RPE. These data suggests that Kir2.1 may be involved in the transport of K+ in the bovine neural retina.

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

    Directory of Open Access Journals (Sweden)

    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

  7. High-resolution analysis of the human retina miRNome reveals isomiR variations and novel microRNAs.

    Science.gov (United States)

    Karali, Marianthi; Persico, Maria; Mutarelli, Margherita; Carissimo, Annamaria; Pizzo, Mariateresa; Singh Marwah, Veer; Ambrosio, Concetta; Pinelli, Michele; Carrella, Diego; Ferrari, Stefano; Ponzin, Diego; Nigro, Vincenzo; di Bernardo, Diego; Banfi, Sandro

    2016-02-29

    MicroRNAs play a fundamental role in retinal development and function. To characterise the miRNome of the human retina, we carried out deep sequencing analysis on sixteen individuals. We established the catalogue of retina-expressed miRNAs, determined their relative abundance and found that a small number of miRNAs accounts for almost 90% of the retina miRNome. We discovered more than 3000 miRNA variants (isomiRs), encompassing a wide range of sequence variations, which include seed modifications that are predicted to have an impact on miRNA action. We demonstrated that a seed-modifying isomiR of the retina-enriched miR-124-3p was endowed with different targeting properties with respect to the corresponding canonical form. Moreover, we identified 51 putative novel, retina-specific miRNAs and experimentally validated the expression for nine of them. Finally, a parallel analysis of the human Retinal Pigment Epithelium (RPE)/choroid, two tissues that are known to be crucial for retina homeostasis, yielded notably distinct miRNA enrichment patterns compared to the retina. The generated data are accessible through an ad hoc database. This study is the first to reveal the complexity of the human retina miRNome at nucleotide resolution and constitutes a unique resource to assess the contribution of miRNAs to the pathophysiology of the human retina.

  8. Regulation of Stem Cell Properties of Müller Glia by JAK/STAT and MAPK Signaling in the Mammalian Retina

    Directory of Open Access Journals (Sweden)

    Krista M. Beach

    2017-01-01

    Full Text Available In humans and other mammals, the neural retina does not spontaneously regenerate, and damage to the retina that kills retinal neurons results in permanent blindness. In contrast to embryonic stem cells, induced pluripotent stem cells, and embryonic/fetal retinal stem cells, Müller glia offer an intrinsic cellular source for regenerative strategies in the retina. Müller glia are radial glial cells within the retina that maintain retinal homeostasis, buffer ion flux associated with phototransduction, and form the blood/retinal barrier within the retina proper. In injured or degenerating retinas, Müller glia contribute to gliotic responses and scar formation but also show regenerative capabilities that vary across species. In the mammalian retina, regenerative responses achieved to date remain insufficient for potential clinical applications. Activation of JAK/STAT and MAPK signaling by CNTF, EGF, and FGFs can promote proliferation and modulate the glial/neurogenic switch. However, to achieve clinical relevance, additional intrinsic and extrinsic factors that restrict or promote regenerative responses of Müller glia in the mammalian retina must be identified. This review focuses on Müller glia and Müller glial-derived stem cells in the retina and phylogenetic differences among model vertebrate species and highlights some of the current progress towards understanding the cellular mechanisms regulating their regenerative response.

  9. Regulation of Stem Cell Properties of Müller Glia by JAK/STAT and MAPK Signaling in the Mammalian Retina.

    Science.gov (United States)

    Beach, Krista M; Wang, Jianbo; Otteson, Deborah C

    2017-01-01

    In humans and other mammals, the neural retina does not spontaneously regenerate, and damage to the retina that kills retinal neurons results in permanent blindness. In contrast to embryonic stem cells, induced pluripotent stem cells, and embryonic/fetal retinal stem cells, Müller glia offer an intrinsic cellular source for regenerative strategies in the retina. Müller glia are radial glial cells within the retina that maintain retinal homeostasis, buffer ion flux associated with phototransduction, and form the blood/retinal barrier within the retina proper. In injured or degenerating retinas, Müller glia contribute to gliotic responses and scar formation but also show regenerative capabilities that vary across species. In the mammalian retina, regenerative responses achieved to date remain insufficient for potential clinical applications. Activation of JAK/STAT and MAPK signaling by CNTF, EGF, and FGFs can promote proliferation and modulate the glial/neurogenic switch. However, to achieve clinical relevance, additional intrinsic and extrinsic factors that restrict or promote regenerative responses of Müller glia in the mammalian retina must be identified. This review focuses on Müller glia and Müller glial-derived stem cells in the retina and phylogenetic differences among model vertebrate species and highlights some of the current progress towards understanding the cellular mechanisms regulating their regenerative response.

  10. Método de preparación del espécimen para evaluar la micromorfología de la interfase adhesiva resina-dentina con un microscopio electrónico de barrido Preparation`s method of the specimen to evaluate the micromorphology of the resin-dentin interface with scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    A Albaladejo

    2007-08-01

    Full Text Available La infiltración con resina de las fibras de colágeno desmineralizadas permiten la formación de una capa híbrida con tags de resina y ramas laterales, creando de esta manera, retenciones micromecánicas de la resina al substrato desmineralizado. Dichas retenciones son el principal mecanismo para la adhesión resina-dentina, siendo la penetración de la resina en la dentina intertubular, el factor de mayor importancia en la obtención de unas adecuadas fuerzas de adhesión. Uno de los instrumentos más usados para estudiar los mecanismos que envuelven el proceso de adhesión ha sido el microscopio electrónico de barrido (MEB. El principio del MEB se basa en imágenes tridimensionales que se construyen punto a punto y línea a línea desde los electrones secundarios. El objetivo de este estudio es describir la preparación de los espécimenes para evaluar la formación de la capa híbrida, los tags de resina y ramas laterales.The infiltration of demineralized collagen fibers with resin permits formation of a hybrid layer with resin tags and adhesive lateral branches, thus creating micromechanical retention of the resin to the demineralized substrate. The micromechanical retention is the chief mechanism for resin bonding to dentin with resin penetration of the intertubular dentin being of major importance in bond strength. One of the first and most widely used tools to study the mechanisms involved in the process of bonding has been the scanning electron microscope (SEM. The principle of SEM is based upon a pseudo three-dimensional image that is built up point-by-point and line-by-line from secondary electrons. The objective of this study is to describe the preparation of the specimens to evaluate the hybrid layer, resin tags and adhesive lateral branches formations.

  11. Microglial cells in organotypic cultures of developing and adult mouse retina and their relationship with cell death.

    Science.gov (United States)

    Ferrer-Martín, Rosa M; Martín-Oliva, David; Sierra, Ana; Carrasco, Maria-Carmen; Martín-Estebané, María; Calvente, Ruth; Marín-Teva, José L; Navascués, Julio; Cuadros, Miguel A

    2014-04-01

    Organotypic cultures of retinal explants allow the detailed analysis of microglial cells in a cellular microenvironment similar to that in the in situ retina, with the advantage of easy experimental manipulation. However, the in vitro culture causes changes in the retinal cytoarchitecture and induces a microglial response that may influence the results of these manipulations. The purpose of this study was to analyze the influence of the retinal age on changes in retinal cytoarchitecture, cell viability and death, and microglial phenotype and distribution throughout the in vitro culture of developing and adult retina explants. Explants from developing (3 and 10 postnatal days, P3 and P10) and adult (P60) mouse retinas were cultured for up to 10 days in vitro (div). Dead or dying cells were recognized by TUNEL staining, cell viability was determined by flow cytometry, and the numbers and distribution patterns of microglial cells were studied by flow cytometry and immunocytochemistry, respectively. The retinal cytoarchitecture was better preserved at prolonged culture times (10 div) in P10 retina explants than in P3 or adult explants. Particular patterns of cell viability and death were observed at each age: in general, explants from developing retinas showed higher cell viability and lower density of TUNEL-positive profiles versus adult retinas. The proportion of microglial cells relative to the whole population of retinal cells was higher in explants fixed immediately after their dissection (i.e., non-cultured) from adult retinas than in those from developing retinas. This proportion was always higher in non-cultured explants than in explants at 10 div, suggesting the death of some microglial cells during the culture. Activation of microglial cells, as revealed by their phenotypical appearance, was observed in both developing and adult retina explants from the beginning of the culture. Immunofluorescence with the anti-CD68 antibody showed that some activated

  12. Study of the Influence of Angiostatin Intravitreal Injection on Vascular Leakage in Retina and Iris of the Experimental Diabetic Rats

    Institute of Scientific and Technical Information of China (English)

    Jing Sima; Jianxing Ma; Sarah X.Zhang; Jiang Guo

    2006-01-01

    Purpose: To examine the effect of an intravitreal injection of angiostatin on vascular leakage in retina and iris of the diabetes and study its possible mechanism.Methods: Experimental diabetes was induced in 24 rats by an intravenous injection of streptozotocin (STZ) during 48 adult rats. Three groups were randomization distributed of them. There were 8 of both normal and diabetic rats in each group. STZ-diabetic rats and age-matched normal rats received an intravitreal injection of 5 μl of sterile PBS (Phosphate Buffered Saline) into the right eye, and the left eye was non-injected in the group A; Angiostatin was injected into the vitreous of the right eye (7.5 μg/5μl/eye), and the left eye received the same volume of sterile PBS as the control in the group B and C. The vascular permeability of retina and iris was measured using the Evans blue method at 2 days following the injection in the group A and B. Expres sion of VEGF in retina was evaluated using western blot analysis 24 hours following the injection in the group C.Results: Diabetic rats showed significant increases of vascular permeability in the retina (P<0.01) and iris (P<0.05). Angiostatin-injected eyes showed significant decreases in vascular permeability in the retina (P<0.01) and iris (P<0.05) comparing with the PBS-injected eyes in STZ-diabetic rats. In contrast, intravitreal injection of the same dose of angiostatin into the age-matched normal rats did not result in any significant reduction in vascular permeability in the retina and iris, when compared with the contralateral eye with PBS injection (P>0.05). Angiostatin injection significantly reduced VEGF level in the retinas of STZ-diabetic rats but did not affect retinal VEGF level in normal rats.Conclusions: Angiostatin significantly reduce pathological vascular permeability in the retina and iris of STZ-diabetic rats but not in normal rats. Angiostatin down-regulates VEGF expression and thus, blocks the major cause of vascular

  13. Amyloid precursor protein is required for normal function of the rod and cone pathways in the mouse retina.

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    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.

  14. Coupling ex vivo electroporation of mouse retinas and luciferase reporter assays to assess rod-specific promoter activity.

    Science.gov (United States)

    Boulling, Arnaud; Escher, Pascal

    2016-07-01

    Ex vivo electroporation of mouse retinas is an established tool to modulate gene expression and to study cell type-specific gene expression. Here we coupled ex vivo electroporation to luciferase reporter assays to facilitate the study of rod-photoreceptor-specific gene promoters. The activity of the rod-specific proximal bovine rhodopsin promoter was significantly increased in C57BL/6J wild-type retinas at postnatal days 1 and 7 by 3.4-fold and 8.7-fold respectively. In C57BL/6J Nr2e3(rd7/rd7) retinas, where the rod photoreceptor-specific nuclear receptor Nr2e3 is not expressed, a significant increase by 2.5-fold was only observed at postnatal day 7. Cone-specific S-opsin promoter activity was not modulated in C57BL/6J wild-type and Nr2e3(rd7/rd7) retinas. Taken together, we describe an easily implementable protocol to assess rod-specific promoter activity in a physiological context resembling that of the developing postnatal mouse retina.

  15. Puerarin enhances superoxide dismutase activity and inhibits RAGE and VEGF expression in retinas of STZ-induced early diabetic rats

    Institute of Scientific and Technical Information of China (English)

    Fang Chen; Hong-Quan Zhang; Jun Zhu; Kai-Yang Liu; Hong Cheng; Guo-Li Li; Shan Xu; Wei-Hong Lv; Zheng-Gao Xie

    2012-01-01

    Objective:To investigate the effects of puerarin on the activity of superoxide dismutase (SOD), and expressions of advanced glycation end-product (AGE) receptor (RAGE) and vascular endothelial growth factor (VEGF) in retinas of streptozotocin (STZ)-induced early diabetic rats. Methods: Diabetic rat models were established by inducing diabetes via intra-peritoneal injection of STZ. Rats were randomly divided into normal (control), diabetic (DM), and DM+puerarin groups. After intra-gastric administration of puerarin (500 mg/kg/day for 4 weeks), levels of SOD and malondialdehyde (MDA) were determined in serum and retina. mRNA and protein expression levels of RAGE and VEGF in retinas were determined by real-time polymerase chain reaction (RT-PCR) (mRNA) and Western blot analysis (protein levels). Results:There was significantly lower SOD activity and significantly higher MDA in serum and retinas of the DM group compared with the two other groups (P<0.05). After treatment with puerarin, SOD activity increased and MDA content decreased in this group (P<0.05). mRNA and protein expression levels of RAGE and VEGF in the DM group were significantly higher than those of the other groups (P<0.05), and decreased after puerarin treatment (P<0.05). Conclusions: Puerarin is able to enhance SOD activity, and inhibit RAGE and VEGF expressions in retinas of STZ-induced early diabetic rats.

  16. Protamine/DNA/Niosome Ternary Nonviral Vectors for Gene Delivery to the Retina: The Role of Protamine.

    Science.gov (United States)

    Puras, G; Martínez-Navarrete, G; Mashal, M; Zárate, J; Agirre, M; Ojeda, E; Grijalvo, S; Eritja, R; Diaz-Tahoces, A; Avilés-Trigueros, M; Fernández, E; Pedraz, J L

    2015-10-05

    The present study aimed to evaluate the incorporation of protamine into niosome/DNA vectors to analyze the potential application of this novel ternary formulation to deliver the pCMS-EGFP plasmid into the rat retina. Binary vectors based on niosome/DNA and ternary vectors based on protamine/DNA/niosomes were prepared and physicochemically characterized. In vitro experiments were performed in ARPE-19 cells. At 1:1:5 protamine/DNA/niosome mass ratio, the resulted ternary vectors had 150 nm size, positive charge, spherical morphology, and condensed, released, and protected the DNA against enzymatic digestion. The presence of protamine in the ternary vectors improved transfection efficiency, cell viability, and DNA condensation. After ocular administration, the EGFP expression was detected in different cell layers of the retina depending on the administration route without any sign of toxicity associated with the formulations. While subretinal administration transfected mainly photoreceptors and retinal pigment epithelial cells at the site of injection, intravitreal administration produced a more uniform distribution of the protein expression through the inner layers of the retina. The protein expression in the retina persisted for at least one month after both administrations. Our study highlights the flattering properties of protamine/DNA/niosome ternary vectors for efficient and safe gene delivery to the rat retina.

  17. Ectopic expression of transcription factor AP-2δ in developing retina: effect on PSA-NCAM and axon routing.

    Science.gov (United States)

    Li, Xiaodong; Monckton, Elizabeth A; Godbout, Roseline

    2014-04-01

    Retinal ganglion cells transmit the visual signal from the retina to the brain. We have previously shown that the activator protein 2 (AP-2)δ (TFAP2D) transcription factor is expressed in one third of ganglion cells in developing retina suggesting a specialized role for these AP-2δ-expressing cells. Here, we address the role of AP-2δ in retina by in ovo electroporation of RCAS/AP-2δ retroviral constructs into the eyes of chick embryos at day 2 of gestation. Ectopic expression of AP-2δ does not affect lineage differentiation in the developing retina. However, immunostaining of retinal tissue with markers associated with axonal growth such as growth-associated protein 43 and polysialic acid-neural cell adhesion molecule (PSA-NCAM) demonstrates axonal misrouting and abnormal axonal bundling. Treatment of AP-2δ-misexpressing retinal cell cultures with endoneuraminidase, an enzyme that removes PSA from NCAM, decreases AP-2δ-induced axonal bundling. Our data suggest a role for AP-2δ in polysialylation of NCAM, with ectopic expression of AP-2δ resulting in premature bundling of emerging axons and misrouting of axons. We propose that expression of AP-2δ in a subset of ganglion cells contributes to the fine-tuning of axonal growth in the developing retina.

  18. Leptin and IL-6 family cytokines synergize to stimulate Müller glia reprogramming and retina regeneration.

    Science.gov (United States)

    Zhao, Xiao-Feng; Wan, Jin; Powell, Curtis; Ramachandran, Rajesh; Myers, Martin G; Goldman, Daniel

    2014-10-09

    Unlike mammals, zebrafish can regenerate a damaged retina. This remarkable regenerative response is mediated by Müller glia (MG) that undergo a reprogramming event that drives their proliferation and the generation of multipotent progenitors for retinal repair. The mechanisms that drive MG reprogramming are poorly understood. Here, we report that Leptin and Gp130-coupled receptors, acting via a Jak/Stat signaling pathway, stimulate MG reprogramming and progenitor formation in the injured retina. Importantly, we find that ascl1a gene expression, which drives MG reprogramming in fish and mammals, is regulated in a Jak/Stat-dependent manner and requires consensus Stat-binding sites for injury-dependent activation. Finally, we identify cytokines that are induced by retinal injury and exhibit a remarkable synergy in their ability to activate Jak/Stat signaling and MG reprogramming in the uninjured retina. Our study not only furthers our understanding of retina regeneration in zebrafish but also suggests new strategies for awakening retina regeneration in mammals.

  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. In vitro expanded stem cells from the developing retina fail to generate photoreceptors but differentiate into myelinating oligodendrocytes.

    Directory of Open Access Journals (Sweden)

    Magdalena Czekaj

    Full Text Available Cell transplantation to treat retinal degenerative diseases represents an option for the replacement of lost photoreceptor cells. In vitro expandable cells isolated from the developing mammalian retina have been suggested as a potential source for the generation of high numbers of donor photoreceptors. In this study we used standardized culture conditions based on the presence of the mitogens FGF-2 and EGF to generate high numbers of cells in vitro from the developing mouse retina. These presumptive 'retinal stem cells' ('RSCs' can be propagated as monolayer cultures over multiple passages, express markers of undifferentiated neural cells, and generate neuronal and glial cell types upon withdrawal of mitogens in vitro or following transplantation into the adult mouse retina. The proportion of neuronal differentiation can be significantly increased by stepwise removal of mitogens and inhibition of the notch signaling pathway. However, 'RSCs', by contrast to their primary counterparts in vivo, i.e. retinal progenitor cells, loose the expression of retina-specific progenitor markers like Rax and Chx10 after passaging and fail to differentiate into photoreceptors both in vitro or after intraretinal transplantation. Notably, 'RSCs' can be induced to differentiate into myelinating oligodendrocytes, a cell type not generated by primary retinal progenitor cells. Based on these findings we conclude that 'RSCs' expanded in high concentrations of FGF-2 and EGF loose their retinal identity and acquire features of in vitro expandable neural stem-like cells making them an inappropriate cell source for strategies aimed at replacing photoreceptor cells in the degenerated retina.

  1. Differentiation potential of bone marrow mesenchymal stem cells into retina in normal and laser-injured rat eye

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jie; SHAN Qing; MA Ping; JIANG Yanming; CHEN Peng; WEN Jingxia; ZHOU You; QIAN Huanwen; PEI Xuetao

    2004-01-01

    Bone marrow mesenchymal stem cells (MSCs) can develop into hematopoietic and mesenchymal lineages but have not been known to participate in the production of retina. Here we report that bone marrow mesenchymal stem cells, after being subretinally transplanted into normal or Nd: YAG laser-injured rat eye, can integrate into RPE layer, photoreceptor layer, bipolar cell layer and ganglion layer. DAPI-labeling detection was used to trace the origin of the repopulating cells. DAPI fluorescence was used to identify retina cells of bone marrow origin 10, 20, 35 and 50 days after transplantation. No formation of rosettes was found but some random cells were found at the end of the observation. MSCs-originated cells spread more widely in the injured retinas than in the normal ones. Immunohistochemical detection showed that though the cells could express neuronal nuclei (NeuN), neuron specific enolase (NSE), glial fibrillary acidic protein (GFAP) and cytokeratin (CK), the proteins expression in the injured transplantation group was abnormal in some region compared with that in the normal transplantation group. Electroretinogram (ERG) showed that ERG-b wave of the injured transplantation group is significantly higher than that of the two laser-injured control groups. These results suggest that a proportion of MSCs can differentiate into retina-like structure in vivo and the differentiation differs in normal and laser-injured retinas.

  2. In vitro expanded stem cells from the developing retina fail to generate photoreceptors but differentiate into myelinating oligodendrocytes.

    Science.gov (United States)

    Czekaj, Magdalena; Haas, Jochen; Gebhardt, Marlen; Müller-Reichert, Thomas; Humphries, Peter; Farrar, Jane; Bartsch, Udo; Ader, Marius

    2012-01-01

    Cell transplantation to treat retinal degenerative diseases represents an option for the replacement of lost photoreceptor cells. In vitro expandable cells isolated from the developing mammalian retina have been suggested as a potential source for the generation of high numbers of donor photoreceptors. In this study we used standardized culture conditions based on the presence of the mitogens FGF-2 and EGF to generate high numbers of cells in vitro from the developing mouse retina. These presumptive 'retinal stem cells' ('RSCs') can be propagated as monolayer cultures over multiple passages, express markers of undifferentiated neural cells, and generate neuronal and glial cell types upon withdrawal of mitogens in vitro or following transplantation into the adult mouse retina. The proportion of neuronal differentiation can be significantly increased by stepwise removal of mitogens and inhibition of the notch signaling pathway. However, 'RSCs', by contrast to their primary counterparts in vivo, i.e. retinal progenitor cells, loose the expression of retina-specific progenitor markers like Rax and Chx10 after passaging and fail to differentiate into photoreceptors both in vitro or after intraretinal transplantation. Notably, 'RSCs' can be induced to differentiate into myelinating oligodendrocytes, a cell type not generated by primary retinal progenitor cells. Based on these findings we conclude that 'RSCs' expanded in high concentrations of FGF-2 and EGF loose their retinal identity and acquire features of in vitro expandable neural stem-like cells making them an inappropriate cell source for strategies aimed at replacing photoreceptor cells in the degenerated retina.

  3. Exclusive multipotency and preferential asymmetric divisions in post-embryonic neural stem cells of the fish retina.

    Science.gov (United States)

    Centanin, Lázaro; Ander, Janina-J; Hoeckendorf, Burkhard; Lust, Katharina; Kellner, Tanja; Kraemer, Isabel; Urbany, Cedric; Hasel, Eva; Harris, William A; Simons, Benjamin D; Wittbrodt, Joachim

    2014-09-01

    The potency of post-embryonic stem cells can only be addressed in the living organism, by labeling single cells after embryonic development and following their descendants. Recently, transplantation experiments involving permanently labeled cells revealed multipotent neural stem cells (NSCs) of embryonic origin in the medaka retina. To analyze whether NSC potency is affected by developmental progression, as reported for the mammalian brain, we developed an inducible toolkit for clonal labeling and non-invasive fate tracking. We used this toolkit to address post-embryonic stem cells in different tissues and to functionally differentiate transient progenitor cells from permanent, bona fide stem cells in the retina. Using temporally controlled clonal induction, we showed that post-embryonic retinal NSCs are exclusively multipotent and give rise to the complete spectrum of cell types in the neural retina. Intriguingly, and in contrast to any other vertebrate stem cell system described so far, long-term analysis of clones indicates a preferential mode of asymmetric cell division. Moreover, following the behavior of clones before and after external stimuli, such as injuries, shows that NSCs in the retina maintained the preference for asymmetric cell division during regenerative responses. We present a comprehensive analysis of individual post-embryonic NSCs in their physiological environment and establish the teleost retina as an ideal model for studying adult stem cell biology at single cell resolution.

  4. Disruption of Fractalkine Signaling Leads to Microglial Activation and Neuronal Damage in the Diabetic Retina

    Directory of Open Access Journals (Sweden)

    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.

  5. An autonomous circadian clock in the inner mouse retina regulated by dopamine and GABA.

    Directory of Open Access Journals (Sweden)

    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

  6. Tracking of CFSE-labeled endothelial progenitor cells in laser-injured mouse retina

    Institute of Scientific and Technical Information of China (English)

    SHI Hui; YANG Wei; CUI Zhi-hua; LU Cheng-wei; LI Xiao-hong; LIANG Ling-ling; SONG E

    2011-01-01

    Background Endothelial progenitor cells (EPCs) transplantation is a promising therapeutic strategy for ischemic retinopathy. The current study aimed to establish a simple, reliable and fluorescent labeling method for tracking EPCs with 5-(and-6)-carboxyfluorescein diacetate succinimidyl ester (CFSE) in laser-injured mouse retina.Methods EPCs were isolated from human umbilical cord blood mononuclear cells, cultivated, and labeled with various concentrations of CFSE. Based on fluorescence intensity and cell morphology, a 15 minutes incubation with 5 μmol/L CFSE at 37℃ was selected as the optimal labeling condition. The survival capability and the apoptosis rate of CFSE-labeled EPCs were measured by Trypan blue staining and Annexin V/PI staining assay respectively. Fluorescence microscopy was used to observe the label stability during the extended culture period. Labeled EPCs were transplanted into the vitreous cavity of pigmented mice injured by retinal laser photocoagulation. Evans Blue angiography and flat mounted retinas were examined to track the labeled cells.Results EPCs labeled with 5 μmol/L CFSE presented an intense green fluorescence and maintained normal morphology, with no significant changes in the survival capability or apoptosis rate after being labeled for 2 days, 1 and 4 weeks. The fluorescence intensity gradually decreased in the cells at the end of 4 weeks. Evans Blue angiography of the retina displayed the retinal capillarity network clearly and fluorescence leakage was observed around photocoagulated spots in the laser-injured mouse model. One week after transplantation of labeled EPCs, the fluorescent cells were identified around the photocoagulated lesions. Four weeks after transplantation, fluorescent tube-like structures were observed in the retinal vascular networks.Conclusion EPCs could be labeled by CFSE in vitro and monitored in vivo for at least 4 weeks, and participate in the repair of injured retinal vessels.

  7. Progressive inflammatory pathology in the retina of aluminum-fed 5xFAD transgenic mice.

    Science.gov (United States)

    Pogue, A I; Dua, P; Hill, J M; Lukiw, W J

    2015-11-01

    At least 57 murine transgenic models for Alzheimer's disease (Tg-AD) have been developed to overexpress the 42 amino acid amyloid-beta (Aβ42) peptide in the central nervous system (CNS). These 'humanized murine Tg-AD models' have greatly expanded our understanding of the contribution of Aβ42 peptide-mediated pro-inflammatory neuropathology to the AD process. A number of independent laboratories using different amyloid-overexpressing Tg-AD models have shown that supplementation of murine Tg-AD diets and/or drinking water with aluminum significantly enhances Aβ42 peptide-mediated inflammatory pathology and AD-type cognitive change compared to animals receiving control diets. In humans AD-type pathology appears to originate in the limbic system and progressively spreads into primary processing and sensory regions such as the retina. In these studies, for the first time, we assess the propagation of Aβ42 and inflammatory signals into the retina of 5xFAD Tg-AD amyloid-overexpressing mice whose diets were supplemented with aluminum. The two most interesting findings were (1) that similar to other Tg-AD models, there was a significantly accelerated development of Aβ42 and inflammatory pathology in 5xFAD Tg-AD mice fed aluminum; and (2) in aluminum-supplemented animals, markers for inflammatory pathology appeared in both the brain and the retina as evidenced by an evolving presence of Aβ42 peptides, and accompanied by inflammatory markers - cyclooxygenase-2 (COX-2) and C-reactive protein (CRP). The results indicate that in the 5xFAD Tg-AD model aluminum not only enhances an Aβ42-mediated inflammatory degeneration of the brain but also appears to induce AD-type pathology in an anatomically-linked primary sensory area that involves vision.

  8. Intricate paths of cells and networks becoming "Cholinergic" in the embryonic chicken retina.

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    Thangaraj, Gopenath; Greif, Alexander; Bachmann, Gesine; Layer, Paul G

    2012-10-01

    Choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) are the decisive enzymatic activities regulating the availability of acetylcholine (ACh) at a given synaptic or nonsynaptic locus. The only cholinergic cells of the mature inner retina are the so-called starburst amacrine cells (SACs). A type-I SAC, found at the outer border of the inner plexiform layer (IPL), forms a synaptic subband "a" within the IPL, while a type-II SAC located at the inner IPL border projects into subband "d." Applying immunohistochemistry for ChAT and AChE on sections of the chicken retina, we here have revealed intricate relationships of how retinal networks became dominated by AChE or by ChAT reactivities. AChE+ cells were first detectable in an embryonic day (E)4 retina, while ChAT appeared 1 day later in the very same cells; at this stage all are Brn3a+, a marker for ganglion cells (GCs). On either side of a faint AChE+ band, indicating the future IPL, pairs of ChAT+ /AChE- /Brn3a- cells appeared between E7/8. Type-I cells had increased ChAT and lost AChE; type-II cells presented less ChAT, but some AChE on their surfaces. Direct neighbors of SACs tended to express much AChE. Along with maturation, subband "a" presented more ChAT but less AChE; in subband "d" this pattern was reversed. In conclusion, the two retinal cholinergic networks segregate out from one cell pool, become locally opposed to each other, and become dominated by either synthesis or degradation of ACh. These "cholinergic developmental divergences" may also have significant physiologic consequences.

  9. 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.

  10. Notch and Wnt signaling mediated rod photoreceptor regeneration by Muller cells in adult mammalian retina.

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    Carolina Beltrame Del Debbio

    Full Text Available BACKGROUND: Evidence emerging from a variety of approaches used in different species suggests that Müller cell function may extend beyond its role of maintaining retinal homeostasis to that of progenitors in the adult retina. Enriched Müller cells in vitro or those that re-enter cell cycle in response to neurotoxin-damage to retina in vivo display multipotential and self-renewing capacities, the cardinal features of stem cells. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrate that Notch and Wnt signaling activate Müller cells through their canonical pathways and that a rare subset of activated Müller cells differentiates along rod photoreceptor lineage in the outer nuclear layer. The differentiation of activated Müller cells along photoreceptor lineage is confirmed by multiple approaches that included Hoechst dye efflux analysis, genetic analysis using retina from Nrl-GFP mice, and lineage tracing using GS-GFP lentivirus in wild type and rd mice in vitro and S334ter rats in vivo. Examination of S334ter rats for head-neck tracking of visual stimuli, a behavioral measure of light perception, demonstrates a significant improvement in light perception in animals treated to activate Müller cells. The number of activated Müller cells with rod photoreceptor phenotype in treated animals correlates with the improvement in their light perception. CONCLUSION/SIGNIFICANCE: In summary, our results provide a proof of principle for non-neurotoxin-mediated activation of Müller cells through Notch and Wnt signaling toward the regeneration of rod photoreceptors.

  11. Overexpression of pairedless Pax6 in the retina disrupts corneal development and affects lens cell survival.

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    Kim, Jiha; Lauderdale, James D

    2008-01-01

    The Pax6 transcription factor is required for multiple aspects of vertebrate eye development. The Pax6 gene encodes isoforms that either contain (Pax6+PD) or lack (Pax6DeltaPD) the N-terminal paired-box DNA-binding domain, in addition to the homeodomain. Alternative promoters control the expression of Pax6+PD and Pax6DeltaPD in the eye. Using a modified bacterial artificial chromosome (BAC) transgene that specifically expresses Pax6DeltaPD, but not paired-containing Pax6, in the normal endogenous pattern, we show that overexpression of Pax6DeltaPD causes a severe microphthalmic phenotype in both wild-type and Pax6-deficient (Sey(/+)) mice in a dosage-dependent manner. The microphthalmic phenotype is due to lens degeneration during embryonic development. Lens development initiates correctly, but cells in the lens undergo apoptotic cell death between E12 and E13. Concomitantly, in these mice, changes in Bmp4, Msx1, and Wnt2b expression were observed in the mesenchymal cells of the developing cornea. To visualize Pax6DeltaPD expression, we developed a dual-reporter Pax6 BAC transgene in which EGFP and DsRed demonstrate paired-containing and pairedless transcripts, respectively. In BAC transgenic mice, DsRed is predominantly expressed in the peripheral neural retina during early eye development, but not in the developing lens or cornea. Later DsRed is strongly expressed in the developing ciliary body, but not in the iris. We suggest that the ratio of Pax6+PD and Pax6DeltaPD isoforms in the distal retina is important for both cornea and lens development, either directly by controlling transcription of necessary growth factors or indirectly by controlling development of the distal neural retina.

  12. 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.

  13. Spectral distribution of local field potential responses to electrical stimulation of the retina

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    Wong, Yan T.; Halupka, Kerry; Kameneva, Tatiana; Cloherty, Shaun L.; Grayden, David B.; Burkitt, Anthony N.; Meffin, Hamish; Shivdasani, Mohit N.

    2016-06-01

    Objective. Different frequency bands of the local field potential (LFP) have been shown to reflect neuronal activity occurring at varying cortical scales. As such, recordings of the LFP may offer a novel way to test the efficacy of neural prostheses and allow improvement of stimulation strategies via neural feedback. Here we use LFP measurements from visual cortex to characterize neural responses to electrical stimulation of the retina. We aim to show that the LFP is a viable signal that contains sufficient information to optimize the performance of sensory neural prostheses. Approach. Clinically relevant electrode arrays were implanted in the suprachoroidal space of one eye in four felines. LFPs were simultaneously recorded in response to stimulation of individual electrodes using penetrating microelectrode arrays from the visual cortex. The frequency response of each electrode was extracted using multi-taper spectral analysis and the uniqueness of the responses was determined via a linear decoder. Main results. We found that cortical LFPs are reliably modulated by electrical stimulation of the retina and that the responses are spatially localized. We further characterized the spectral distribution of responses, with maximum information being contained in the low and high gamma bands. Finally, we found that LFP responses are unique to a large range of stimulus parameters (∼40) with a maximum conveyable information rate of 6.1 bits. Significance. These results show that the LFP can be used to validate responses to electrical stimulation of the retina and we provide the first steps towards using these responses to provide more efficacious stimulation strategies.

  14. Parvalbumin immunoreactivity is enhanced by brain-derived neurotrophic factor in organotypic cultures of rat retina.

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    Rickman, D W

    1999-11-15

    The rodent retina undergoes considerable postnatal neurogenesis and phenotypic differentiation, and it is likely that diffusible neurotrophic factors contribute to this development and to the subsequent formation of functional retinal circuitry. Accordingly, perturbation of specific neurotrophin ligand-receptor interactions has provided valuable information as to the fundamental processes underlying this development. In the present studies we have built upon our previous observation that suppression of expression of trk(B), the high-affinity receptor for brain-derived neurotrophic factor (BDNF), in the postnatal rat retina results in the alteration of a specific interneuron in the rod pathway-the parvalbumin (PV)-immunoreactive AII amacrine cell. Here, we isolated retinas from newborn rats and maintained them in organotypic culture for up to 14 days (approximating the time of eye opening, in vivo) in the presence of individual neurotrophins [BDNF or nerve growth factor (NGF)]. We then examined histological sections of cultures for PV immunoreactivity. In control cultures, only sparse PV-immunostained cells were observed. In cultures supplemented with NGF, numerous lightly immunostained somata were present in the inner nuclear layer (INL) at the border of the inner plexiform layer (IPL). Many of these cells had rudimentary dendritic arborizations in the IPL. Cultures supplemented with BDNF displayed numerous well-immunostained somata at the INL/IPL border that gave rise to elaborate dendritic arborizations that approximated the morphology of mature AII amacrine cells in vivo. These observations indicate that neurotrophins have specific effects upon the neurochemical and, perhaps, morphological differentiation of an important interneuron in a specific functional retinal circuit.

  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