RESUMO
Hypoxia-induced glutamate accumulation in neural tissues results in damage to neurons through excitotoxic mechanisms via activation of glutamate receptors (GluRs). Here we examine whether hypoxia in the developing retina would cause activation of the ionotropic α-amino-3-hydroxy-5-methylisoxazole-4-propioate (AMPA) GluRs and increase in Ca(2+) influx into retinal ganglion cells (RGCs) that might ultimately lead to their death. Neonatal Wistar rats were subjected to hypoxia for 2h and then sacrificed at various time points after the exposure together with normal age matched control rats. Primary cultures of RGCs were also prepared and subjected to hypoxia. Expression of AMPA glutamate receptor (GluR) 1-4 was examined in the retina. Additionally, expression of GluRs, intracellular Ca(2+) influx, reactive oxygen species (ROS) generation and cell death were investigated in cultured RGCs. GluR1-4 mRNA and protein expression showed a significant increase (P < 0.01) over control values after the hypoxic exposure both in vivo and in vitro. Cells expressing GluR1-4 in the retina were identified as RGCs by double immunofluorescence labeling with Thy1.1. Increased intracellular Ca(2+) in cultured RGCs following hypoxic exposure was reduced (P < 0.01) by 10 µM AMPA antagonist 6, 7-dinitroquinoxaline-2,3-dione (DNQX). Our results suggest that following a hypoxic insult, an increased amount of glutamate accumulates in the neonatal retina. This would then activate AMPA receptors which may damage RGCs through increased Ca(2+) accumulation and ROS generation. The involvement of AMPA receptors in damaging the RGCs is evidenced by suppression of intracellular Ca(2+) influx by DNQX which also decreased ROS generation and cell death by 50%.
Assuntos
Hipóxia/tratamento farmacológico , Hipóxia/metabolismo , Quinoxalinas/farmacologia , Receptores de AMPA/metabolismo , Células Ganglionares da Retina/metabolismo , Animais , Animais Recém-Nascidos , Cálcio/metabolismo , Antagonistas de Aminoácidos Excitatórios/farmacologia , Hipóxia/patologia , Fármacos Neuroprotetores/farmacologia , Cultura Primária de Células , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Receptores de AMPA/antagonistas & inibidores , Células Ganglionares da Retina/efeitos dos fármacos , Células Ganglionares da Retina/patologiaRESUMO
PURPOSE: To investigate the possible roles of retinal photoreceptors in macular oedema and retinal angiogenesis with particular reference to the mode of action of laser therapy. METHODS: (i) Studies in rats made hypoxic for 2 h by administering an oxygen/nitrogen mixture of reduced oxygen content, and growth factors determined by RT-PCR, western blotting, and immunohistochemistry. Assessment of blood-retinal barrier integrity using fluorescent and electron-dense tracers. (ii) Studies in pigs with one retina made hypoxic by selective embolisation of the retinal capillary circulation with fluorescent microspheres. (iii) Assessment of laser therapy in selected cases of retinal neovascularisation indicating a role for photoreceptors. RESULTS: In the hypoxic retina, angiogenic and vascular permeability factors such as vascular endothelial growth factor (VEGF), nitric oxide synthases (NOSs), and insulin-like growth factor-1 are upregulated in retinal astrocytes and Müller cells but are also present in large amount in the photoreceptors. Hypoxia-inducible factor-1 (HIF-1) is upregulated in retinal glial cells but not in the photoreceptors, suggesting that growth factors in the photoreceptors may not have been generated there. The tracer dye, rhodium isothiocyanate, leaking from an abnormally permeable inner blood-retinal barrier in the hypoxic retina accumulates in the photoreceptors. CONCLUSIONS: The results indicate that laser treatment of macular oedema or retinal neovascularisation may obtain its effect not only by improving oxygen availability in the inner retina, but also by reducing the load of angiogenic/permeability factors that accumulate in the photoreceptors in hypoxic/ischaemic conditions.
Assuntos
Terapia a Laser , Neovascularização Patológica/cirurgia , Papiledema/cirurgia , Células Fotorreceptoras de Vertebrados/metabolismo , Animais , Astrócitos/metabolismo , Barreira Hematorretiniana/patologia , Western Blotting , Hipóxia , Fator 1 Induzível por Hipóxia/metabolismo , Imuno-Histoquímica , Fator de Crescimento Insulin-Like I/metabolismo , Neovascularização Patológica/metabolismo , Neovascularização Patológica/fisiopatologia , Neuroglia/metabolismo , Óxido Nítrico Sintase/metabolismo , Papiledema/metabolismo , Papiledema/fisiopatologia , Ratos , Retina/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Suínos , Regulação para Cima , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
The blood-retinal barrier (BRB) plays an important role in the homeostatic regulation of the microenvironment in the retina. It consists of inner and outer components, the inner BRB (iBRB) being formed by the tight junctions between neighbouring retinal capillary endothelial cells and the outer barrier (oBRB) by tight junctions between retinal pigment epithelial cells. Astrocytes, Müller cells and pericytes contribute to the proper functioning of the iBRB. In many clinically important conditions including diabetic retinopathy, ischaemic central retinal vein occlusion, and some respiratory diseases, retinal hypoxia results in a breakdown of the iBRB. Disruption of the iBRB associated with increased vascular permeability, results in vasogenic oedema and tissue damage, with consequent adverse effects upon vision. Factors such as enhanced production of vascular endothelial growth factor (VEGF), NO, oxidative stress and inflammation underlie the increased permeability of the iBRB and inhibition of these factors is beneficial. Experimental studies in our laboratory have shown melatonin to be a protective agent for the iBRB in hypoxic conditions. Although oBRB breakdown can occur in conditions such as accelerated hypertension and the toxaemia of pregnancy, both of which are associated with choroidal ischaemia and in age-related macular degeneration (ARMD), and is a feature of exudative (serous) retinal detachment, our studies have shown that the oBRB remains intact in hypoxic/ischaemic conditions. Clinically, anti-VEGF therapy has been shown to improve vision in diabetic maculopathy and in neovascular ARMD. The visual benefit in both conditions appears to arise from the restoration of BRB integrity with a reduction of retinal oedema.
Assuntos
Barreira Hematorretiniana/fisiologia , Hipóxia/metabolismo , Isquemia/metabolismo , Doenças Retinianas/metabolismo , Vasos Retinianos/fisiologia , Inibidores da Angiogênese/uso terapêutico , Permeabilidade Capilar , Humanos , Doenças Retinianas/tratamento farmacológico , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidoresRESUMO
As the response of the adult retina to hypoxia is likely to differ from that already established in the neonatal animal, this study was undertaken to examine the expression patterns of insulin-like growth factor-I (IGF-I) and -II (IGF-II), angiopoietin-2 (Ang-2), and pigment epithelium-derived growth factor (PEDF) in normal and hypoxic retinas of adult rats. In the latter, the retinas were examined from 3 hr to 14 days after hypoxic exposure. The mRNA and protein expression of IGF-I, IGF-II, Ang-2, and PEDF in the retina was determined by real-time RT-PCR, Western blotting, and immunohistochemistry. The results showed up-regulated expression of IGF-I, IGF-II, and Ang-2 mRNA and protein in response to hypoxia, whereas PEDF expression was drastically reduced, suggesting that increased expression of IGF-I and IGF-II may be involved not only in neovascularization but also in neuroprotection in hypoxic conditions. The up-regulation of Ang-2, a proangiogenic factor, and the down-regulation of PEDF, an antiangiogenic factor, is indicative of an imbalance between pro- and antiangiogenic factors in the hypoxic retina that may favor neovascularization. This was supported by the increased density of rat endothelial cell antigen-1 (RECA-1) protein quantification and RECA-1-stained blood vessels in the inner retina.
Assuntos
Angiopoietina-2/metabolismo , Proteínas do Olho/metabolismo , Hipóxia/metabolismo , Fatores de Crescimento Neural/metabolismo , Retina/metabolismo , Doenças Retinianas/metabolismo , Serpinas/metabolismo , Somatomedinas/metabolismo , Angiopoietina-2/genética , Angiopoietinas/metabolismo , Animais , Western Blotting , Regulação para Baixo , Proteínas do Olho/genética , Imuno-Histoquímica , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/metabolismo , Fator de Crescimento Insulin-Like II/genética , Fator de Crescimento Insulin-Like II/metabolismo , Fatores de Crescimento Neural/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Recombinases Rec A/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Serpinas/genética , Somatomedinas/genética , Regulação para CimaRESUMO
Reactive changes in astrocytes and Müller cells in the retina of adult rats subjected to hypoxia were investigated. Along with this, the integrity of the blood-retinal barrier (BRB) was assessed using fluorescent and electron-dense tracers. In hypoxic rats, mRNA and protein expression of glial fibrillary acidic protein (GFAP) and aquaporin-4 (AQ4) were significantly increased. AQ4 immunoreactive cells were identified as astrocytes and Müller cells by double immunofluorescence labelling. Another alteration in the hypoxic retina was marked reduction in melatonin content compared to controls. In this connection, administration of exogenous melatonin reduced the tissue concentration of vascular endothelial growth factor (VEGF) and nitric oxide (NO); both were elevated in hypoxic rats. A major structural change in the hypoxic retina was swelling of astrocyte and Müller cell processes but this was noticeably attenuated after melatonin administration. Following an intraperitoneal or intravenous injection of rhodamine isothiocyanate (RhIC) or horseradish peroxidase (HRP), leakage of both tracers was observed in the retina in hypoxic rats but not in the controls, indicating that the functional integrity of the BRB is compromised in hypoxia/reoxygenation. It is suggested that enhanced tissue concentration of VEGF and NO production in the hypoxic retina contribute to increased permeability of the retinal blood vessels. The concurrent up-regulation of AQ4, a water-transporting protein, in astrocytes and Müller cells in hypoxia suggests its involvement in oedema formation. Since melatonin effectively reduced the vascular permeability in the retina of hypoxic rats, as evidenced by reduced leakage of RhIC, we suggest that its administration may be of potential benefit in the management of retinal oedema associated with retinal hypoxia.
Assuntos
Barreira Hematorretiniana , Hipóxia/patologia , Melatonina/uso terapêutico , Retina/ultraestrutura , Doenças Retinianas/tratamento farmacológico , Animais , Antioxidantes , Aquaporina 4/genética , Aquaporina 4/metabolismo , Astrócitos/metabolismo , Permeabilidade Capilar/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Sequestradores de Radicais Livres/farmacocinética , Sequestradores de Radicais Livres/uso terapêutico , Proteína Glial Fibrilar Ácida/genética , Proteína Glial Fibrilar Ácida/metabolismo , Peroxidase do Rábano Silvestre , Hipóxia/metabolismo , Hipóxia/fisiopatologia , Masculino , Melatonina/farmacocinética , Microscopia Eletrônica , Óxido Nítrico/biossíntese , RNA Mensageiro/genética , Ratos , Ratos Wistar , Retina/metabolismo , Doenças Retinianas/metabolismo , Doenças Retinianas/patologia , Doenças Retinianas/fisiopatologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Rodaminas , Regulação para Cima , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
AIMS: This study reports the metastatic death rate after trans-scleral local resection of uveal melanoma and identifies relevant risk factors. METHODS: Local resection was performed in 332 patients (mean age 51 years), with follow up ranging to 20.9 years (median for living patients 33 months). The tumours had a mean largest basal diameter of 13.1 mm and mean thickness of 7.5 mm, with 135 containing epithelioid cells. Risk factors were identified by Cox analysis and metastatic rates demonstrated using Kaplan-Meier curves. RESULTS: There were 52 deaths from metastatic melanoma. The significant risk factors were (i) age more than 60 years at treatment (p = 0.001), (ii) mixed/epithelioid tumours (p = 0.003), (iii) superior location of mixed/epithelioid tumours (over and above (ii)) (p = 0.001), (iv) largest basal tumour diameter of 16 mm or more (p < 0.001), (v) lack of adjunctive radiotherapy (p = 0.031), (vi) secondary enucleation for bulky residual/recurrent tumour (p = 0.002), and (vii) secondary enucleation for small residual/recurrent tumour extraocularly (p = 0.019). Metastatic death was not significantly associated with (i) incomplete tumour excision (p = 0.163), and (ii) small residual/recurrent tumour treated by enucleation (p = 0.855). CONCLUSIONS: Survival diminished from 92% at 15 years if less than two risk factors were present to less than 30% in 3.5 years if more than three risk factors were present.
Assuntos
Melanoma/secundário , Melanoma/cirurgia , Neoplasias Uveais/cirurgia , Terapia Combinada , Enucleação Ocular , Feminino , Seguimentos , Humanos , Masculino , Melanoma/patologia , Melanoma/radioterapia , Pessoa de Meia-Idade , Fatores de Risco , Análise de Sobrevida , Neoplasias Uveais/patologia , Neoplasias Uveais/radioterapiaRESUMO
AIMS: The aims of this study were to report local tumour control after trans-scleral local resection of uveal melanoma and to identify risk factors for (i) clinical residual tumour recognised immediately after surgery, and (ii) delayed tumour recurrence from subclinical microscopic deposits. METHODS: The sample included 310 patients, treated by choroidectomy (188), cyclochoroidectomy (87), or iridocyclectomy (35), with follow up ranging from 42 days to 20.9 years (median 36 months), a mean basal largest tumour diameter of 13.2 mm, and a mean tumour thickness of 7.4 mm. RESULTS: There were 24 patients with residual tumour. Forward stepwise logistic regression indicated that posterior extension to within 1 disc diameter of the optic disc or fovea was the sole best indicator of the risk of residual disease (p < 0.001). After excluding these cases, 286 patients were studied for the development of delayed local recurrence, which occurred in 57 cases. Forward stepwise multivariate analysis showed the statistically significant predictors for recurrent tumour to be epithelioid cellularity (p = 0.002), posterior tumour extension to < 1 disc diameter of disc of fovea (p = 0.002), large tumour diameter > or = 16 mm (p = 0.019) and lack of adjunctive plaque radiotherapy (p = 0.018). CONCLUSIONS: The recurrence rate at 4 years varied from 6% if no risk factors were present to 57% if there were more than two risk factors.
Assuntos
Melanoma/cirurgia , Recidiva Local de Neoplasia/etiologia , Neoplasia Residual/etiologia , Neoplasias Uveais/cirurgia , Feminino , Seguimentos , Humanos , Masculino , Melanoma/patologia , Pessoa de Meia-Idade , Fatores de Risco , Resultado do Tratamento , Neoplasias Uveais/patologiaRESUMO
Mortality after enucleation for intraocular melanoma is 50% in 10 to 15 years. Death rates after conservative management by local resection, proton beam irradiation, or plaque radiotherapy appear to be similar to post-enucleation mortality in retrospective studies. Risk factors for metastatic death include tumor size, location, cell type, and age of patient and are common to all forms of management including enucleation. The eye and vision can be retained in most cases treated conservatively but choice of conservative management is dependent on patient and tumor characteristics. Any adverse effect on survival posed by conservative management is likely to be slight. Randomized prospective trials that would be needed to establish whether this is true in the case of local resection or proton beam irradiation would be difficult to mount and are unlikely to be conducted.
Assuntos
Melanoma/terapia , Neoplasias Uveais/terapia , Quimioterapia Adjuvante , Terapia Combinada , Enucleação Ocular , Humanos , Hipertermia Induzida , Melanoma/diagnóstico , Melanoma/mortalidade , Melanoma/fisiopatologia , Radioterapia Adjuvante , Fatores de Risco , Taxa de Sobrevida , Neoplasias Uveais/diagnóstico , Neoplasias Uveais/mortalidade , Neoplasias Uveais/fisiopatologia , Visão Ocular/fisiologiaRESUMO
Local resection of choroidal melanomas is not widely performed so that the indications for this operation have not previously been defined statistically. Univariate and multivariate Cox regression analyses were used to identify the factors influencing visual acuity after 163 completed local resections for choroidal melanoma in patients with a preoperative visual acuity of counting fingers or better. The variables included in the analyses were patient age and sex; eye laterality and preoperative visual acuity; location of anterior and posterior tumour margins; tumour location (coronal and sagittal); tumour diameter, thickness, and cell type; ocular decompression by vitrectomy; and adequacy of surgical clearance. The surgical resections were performed using a lamellar scleral flap for eye closure, hypotensive anaesthesia for haemostasis, and, in the later years, ocular decompression by pars plana vitrectomy to improve access. The patients (94 men, 69 women) had a mean age of 50 years. The tumours had a mean diameter of 13.3 mm and a mean thickness of 7.4 mm, with 38 tumours extending to within 1 disc diameter (DD) of the optic disc, fovea or both (that is, 'posterior tumour extension'). Cox multivariate analysis showed that the most significant preoperative factors for predicting retention of good vision (6/12 or better) were nasal tumour location (p = 0.002) and distance of more than 1 DD between the tumour and the optic disc or fovea (p = 0.010). The most significant predictive risk factor for severe visual loss (hand movements or worse) was posterior tumour extension to within 1 DD of the optic disc and/or fovea (p = 0.009). One year post-operatively, all 28 patients with nasal tumours not extending to within 1 DD of the optic disc or fovea retained the eye with 57% having vision of 6/12 or better and 93% having vision of counting fingers or better. In 68 patients with temporal tumours, 90% retained the eye at 1 year with preservation of vision of counting fingers or better in 82% of 56 eyes without posterior tumours extension and in 50% of 12 eyes with posterior tumour extension. In patients with choroidal melanoma, conservation of the eye and vision can be achieved by local resection, especially if the tumour is located nasally and does not extend close to the disc or fovea.
Assuntos
Neoplasias da Coroide/cirurgia , Corioide/cirurgia , Melanoma/cirurgia , Acuidade Visual , Adulto , Idoso , Neoplasias da Coroide/fisiopatologia , Feminino , Humanos , Masculino , Melanoma/fisiopatologia , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Descolamento Retiniano/etiologia , Fatores de Risco , Transtornos da Visão/etiologia , Visão Ocular/fisiologiaRESUMO
The histopathological features of uveitis and retinal vasculitis in acute experimental allergic encephalomyelitis (EAE) were investigated using light and electron microscopy. Lewis rats were immunized by spinal cord homogenate, complete Freund's adjuvant and Bordetella pertussis. The eyes of rats with EAE exhibited vasculitis in the iris, trabeculitis and endothelial abnormalities in the retinal vessels; vasculitis was observed in the optic nerve and brain. Endothelial cells in the vessels in the iris, retina, optic nerve and central nervous system were noted to be elevated (high endothelial-like venules, or HELV). Inflammatory cells in the vascular lumen were attached to the surface of endothelial cells in abnormal areas in the iris. By comparison with the findings in the iris and retina, there were no significant changes in the vessels of the ciliary body and choroid. The ultrastructural features indicated that anterior uveitis in acute EAE resulted from vasculitis in the iris due to changes of the endothelial cells and was not due to a reaction against the myelinated nerves or any other particular components of the iris. In addition, our results suggested that vasculitis in the iris was consequent upon specialized changes of the endothelial cells similar to HELV which were responsible for the transcellular emigration of lymphocytes in other inflammatory diseases or in experimental models. HELV change plays an important role in the perivascular inflammatory process in the iris, retina, optic nerve and central nervous system in EAE and possibly in multiple sclerosis.
Assuntos
Encefalomielite Autoimune Experimental/patologia , Doenças Retinianas/patologia , Uveíte/patologia , Animais , Encéfalo/ultraestrutura , Corpo Ciliar/ultraestrutura , Endotélio Vascular/ultraestrutura , Iris/ultraestrutura , Nervo Óptico/ultraestrutura , Ratos , Ratos Endogâmicos Lew , Vasos Retinianos/ultraestruturaRESUMO
The heat shock response was examined in cultured human retinal pigment epithelium (RPE) using indirect immunofluorescence. Mild head shock (39.5-40 degrees C for 1 hr) caused no changes in cell morphology and cells continued to produce the intermediate filament proteins, cytokeratin (keratin) and vimentin. In addition, cells subjected to mild heat shock demonstrated the presence of a heat shock protein (HSP-90). After severe heat shock (45.5-46 degrees C for 1 hr) most cells showed marked morphological changes and, in addition, HSP-90 and/or stress-induced 40 kDa protein production was significantly enhanced. The expression of vimentin was relatively well preserved whereas that of keratin was markedly reduced. When the more severe grade of heat shock was preceded by mild heat shock 20-24 hr earlier, the subsequent severe heat shock resulted in less marked morphological change than in cells not preconditioned and, in addition, the expression of both vimentin and keratin was relatively well preserved. Mildly heat shocked cells appeared to gain thermal resistance supporting the theory that the concomitant synthetic capacity for HSP and normal cellular proteins contributes to thermal resistance. In doubly heat shocked cells, however, HSP-90 expression was not enhanced. The discrepancy between the expression of HSP and thermal resistance is discussed.
Assuntos
Proteínas de Choque Térmico/biossíntese , Temperatura Alta , Epitélio Pigmentado Ocular/patologia , Idoso , Células Cultivadas , Humanos , Queratinas/biossíntese , Pessoa de Meia-Idade , Epitélio Pigmentado Ocular/metabolismo , Vimentina/biossínteseRESUMO
P1 and P2 components of visual evoked responses (VERs) to flash stimuli were compared between patients diagnosed as suffering from Senile Dementia of the Alzheimer Type (AD) and elderly controls. Additionally the P100 component of the VER to pattern reversal stimuli at high and low contrast and using large and small check patterns was compared. Significant differences between moderate AD patients and the normal elderly were found for the P2 component of the flash stimulus and for the P100 component of the high spatial frequency pattern reversal stimuli at low contrast. These findings suggest a deficit in primary visual processing and a selective deficit in secondary visual processing in moderate cases of dementia. This indicates that visual processing capacities of AD patients decline as the disease progresses in line with the continual degeneration of neuronal populations involved with vision.
Assuntos
Demência/fisiopatologia , Potenciais Evocados Visuais/fisiologia , Idoso , Doença de Alzheimer/fisiopatologia , Doença de Alzheimer/psicologia , Demência/psicologia , Feminino , Humanos , Estimulação LuminosaRESUMO
Based upon the author's considerable experience of trans-scleral resection of malignant melanoma of the choroid, a technique has been developed for the biopsy of tissues of the posterior segment of the eye. Its use in the management of atypical malignancy posing diagnostic difficulty and in the investigation of selected case of acute retinal necrosis, uveitis and retinal pigment epitheliopathy is described. In 34 trans-scleral biopsies of choroid, RPE and in some cases, retina, an adverse result occurred in only one case, this it was thought being due to not including pars plana vitrectomy as part of the biopsy technique. Pars plana vitrectomy is now regarded as an integral part of this form of biopsy.
Assuntos
Biópsia/métodos , Oftalmopatias/patologia , Olho/patologia , Corioide/patologia , Neoplasias Oculares/patologia , Neoplasias Oculares/secundário , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Epitélio Pigmentado Ocular/patologia , Retina/patologia , Síndrome de Necrose Retiniana Aguda/patologia , Uveíte/patologiaRESUMO
Twenty-eight patients from 25 maternal lineages with Leber's hereditary optic neuropathy (LHON) were investigated by restriction enzyme analysis for the presence or absence of the point mutation described by Wallace et al. The mutation was identified in 18 of 25 (72%) families with LHON. This provides further evidence that this mutation is present in the majority of patients with LHON. In 19 of these families with LHON, additional analysis using sequencing, oligonucleotide probing, and competitive oligonucleotide priming of PCR products was performed. In 14 cases with the site loss the point mutation was present, and five without the site loss had the wild type sequence in this region.
Assuntos
DNA Mitocondrial/genética , Atrofias Ópticas Hereditárias/genética , Feminino , Humanos , Masculino , Mutação , Hibridização de Ácido Nucleico , Sondas de Oligonucleotídeos , Reação em Cadeia da PolimeraseRESUMO
A sensitive radioimmunoassay has been developed which allows rapid quantitation of rod outer segment (ROS) phagocytosis by retinal pigment epithelial (RPE) explants in vitro. It involves the use of an antiopsin antiserum, in conjunction with 125I-protein A as a second antibody, and utilizes permeabilization with ethanol to distinguish between the binding and ingestion phases of phagocytosis. This procedure will be used in the future to investigate potential regulatory factors of ROS phagocytosis by retinal pigment epithelium and to evaluate animal models of retinal degeneration.
Assuntos
Fagocitose/imunologia , Epitélio Pigmentado Ocular/imunologia , Radioimunoensaio/métodos , Segmento Externo da Célula Bastonete/imunologia , Animais , Bovinos , Ensaio de Imunoadsorção Enzimática , Proteínas do Olho/imunologia , Células Fotorreceptoras/imunologia , Reprodutibilidade dos Testes , Pigmentos da Retina/imunologia , Opsinas de Bastonetes , Sensibilidade e EspecificidadeRESUMO
The visual acuity, the difference in sensitivity of the two eyes to light (brightness ratio), and contrast sensitivity were assessed in 28 patients with chronic open angle glaucoma and compared with those of 41 normal controls of similar ages and visual acuity. The results obtained were related to the results of Tübingen visual field analysis in patients with glaucoma. Twenty-four of the 28 glaucoma patients (86%) had a significant disparity in brightness ratio between the two eyes. This was found to match the frequency of visual field loss. Moreover, there was a significant relationship between the interocular differences in brightness sense and the difference in the degree of visual field loss between the two eyes. Of the glaucoma patients 39% had sum contrast sensitivities outside the normal range for age-matched normal controls. No significant correlation was found between the interocular difference in brightness sense and the visual acuity or the interocular difference in sum contrast sensitivity. It is concluded that, in the presence of a normal visual acuity, the brightness ratio test warrants evaluation as a potential screening test for chronic open angle glaucoma.
Assuntos
Sensibilidades de Contraste , Discriminação Psicológica , Glaucoma de Ângulo Aberto/fisiopatologia , Estimulação Luminosa , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Testes Visuais , Acuidade Visual , Campos VisuaisRESUMO
Previous studies have shown that bovine retinas incubated with [3H]galactose incorporated it, unmodified, into large molecules. Light and electron microscope autoradiography showed a significant proportion of the label to be in cone inner segments, and pulse-chase studies showed it was subsequently transported to the synaptic pedicles. In this report, evidence is presented to show that the galactose-labelled macromolecules are resistant to hydrolysis by proteolytic enzymes, testicular hyaluronidase, chondroitinase ABC, beta-glucosidase and beta-glucuronidase, but are readily degraded by alpha-amylase and beta-galactosidase, and to a lesser extent by beta-amylase. Treatment with alpha-amylase also leads to specific removal of radioactivity from cone inner segments and pedicles, as judged by light-microscopic autoradiography. These studies appear to indicate that the cone-specific galactose label is in glycogen or glycogen-like molecules.