Neuroprotective effects of erythropoietin on rat retinas subjected to oligemia

OBJECTIVES: Erythropoietin may have neuroprotective potential after ischemia of the central nervous system. Here, we conducted a study to characterize the protective effects of erythropoietin on retinal ganglion cells and gliotic reactions in an experimentally induced oligemia model. METHODS: Rats were subjected to global oligemia by bilateral common carotid artery occlusion and then received either vehicle or erythropoietin via intravitreal injection after 48 h; they were euthanized one week after the injection. The densities of retinal ganglion cells and contents of glial fibrillary acidic protein (astrocytes/Müller cells) and cluster of differentiation 68 clone ED1 (microglia/macrophages), assessed by fluorescence intensity, were evaluated in frozen retinal sections by immunofluorescence and epifluorescence microscopy. RESULTS: Retinal ganglion cells were nearly undetectable one week after oligemia compared with the sham controls; however, these cells were partially preserved in erythropoietin-treated retinas. The contents of glial fibrillary acidic protein and cluster of differentiation 68 clone ED1, markers for reactive gliosis, were significantly higher in retinas after bilateral common carotid artery occlusion than those in both sham and erythropoietin-treated retinas. CONCLUSIONS: The number of partially preserved retinal ganglion cells in the erythropoietin-treated group suggests that erythropoietin exerts a neuroprotective effect on oligemic/ischemic retinas. This effect could be related to the down-modulation of glial reactivity, usually observed in hypoxic conditions, clinically observed during glaucoma or retinal artery occlusion conditions. Therefore, glial reactivity may enhance neurodegeneration in hypoxic conditions, like normal-tension glaucoma and retinal ischemia, and erythropoietin is thus a candidate to be clinically applied after the detection of decreased retinal blood flow.

Avaliação dos membros superiores na doença de Parkinson: implicações para a Reabilitação Física / Assessment of upper limbs in Parkinson's disease: implications for Physical Rehabilitation

A doença de Parkinson é uma desordem neurológica com impacto negativo na motricidade e qualidade de vida dos pacientes. O comprometimento motor inclui dificuldades para a marcha, equilíbrio e atividades de vida diária. Contudo, pouca atenção é dada aos aspectos de avaliação e reabilitação física dos membros superiores na doença de Parkinson. Sendo assim, o presente artigo apresenta instrumentos de avaliação no contexto da Classsificação Internacional de Funcionalidade, Incapacidade e Saúde que são relatados na literatura e que podem servir como desfechos clínicos para verificar a evolução dos pacientes com DP na reabilitação física.

Parkinson's disease is a neurological disorder with a negative impact on motor function and quality of life of patients. The motor impairment includes diffulites in walking, balance and daily activities. However, little attention is paid to aspects of evaluation and physical rehabilitation for upper limbs in Parkinson's disease. Therefore, this paper presents assessment tools in the context of the International Colassification of Functioning, Disability and Health that are reported in the literature and which can serve as clinical outcomes to verify the evolution of Parkinson's disease patients in physical rehabilitation.

Reduced occurrence of programmed cell death and gliosis in the retinas of juvenile rabbits after shortterm treatment with intravitreous bevacizumab

OBJECTIVE: Bevacizumab has been widely used as a vascular endothelial growth factor antagonist in the treatment of retinal vasoproliferative disorders in adults and, more recently, in infants with retinopathy of prematurity. Recently, it has been proposed that vascular endothelial growth factor acts as a protective factor for neurons and glial cells, particularly in developing nervous tissue. The purpose of this study was to investigate the effects of bevacizumab on the developing retinas of juvenile rabbits. METHODS: Juvenile rabbits received bevacizumab intravitreously in one eye; the other eye acted as an untreated control. Slit-lamp and fundoscopic examinations were performed both prior to and seven days after treatment. At the same time, retina samples were analyzed using immunohistochemistry to detect autophagy and apoptosis as well as proliferation and glial reactivity. Morphometric analyses were performed, and the data were analyzed using the Mann-Whitney U test. RESULTS: No clinical abnormalities were observed in either treated or untreated eyes. However, immunohistochemical analyses revealed a reduction in the occurrence of programmed cell death and increases in both proliferation and reactivity in the bevacizumab-treated group compared with the untreated group. CONCLUSIONS: Bevacizumab appears to alter programmed cell death patterns and promote gliosis in the developing retinas of rabbits; therefore, it should be used with caution in developing eyes.

Modificações estruturais agudas da córnea do rato (rattus albino) provocadas pelos raios X / Acute structurals modifications of the rat cornea caused by X rays

Objetivos: Análise histológica da ação de diferentes doses de Raios X sobre a córnea do rato e acompanhamento semanal da evolução das lesões provocadas pelos Raios X. Local: Tese apresentada à Faculdade de Medicina - Universidade Federal do Rio de Janeiro, como parte dos requisitos para obtenção do grau de Mestre em Medicina, área de concentração - Departamento de Oftalmologia e Otorrinolaringologia. Método: Ratos (Rattus albino) da linhagem Wister (albino holandês) foram distribuídos em 3 (três) grupos contendo cada grupo 4 (quatro) animais e as suas córneas foram submetidas aos Raios X, operando 45KV e 10 mA nas doses de 15.10, 12.59 e 4.19 Gy, respectivamente. Semanalmente, um animal era sacrificado com éter etílico e olho enucleado. Os cortes corados pela hematoxilina-eosina foram observados na microscopia óptica. Resultados: Verificou-se uma relação dose-efeito e a existência de um limiar: abaixo de uma determinada dose as córneas irradiadas eram semelhantes às córneas não irradiadas (controle). Qualitativamente os efeitos observados nas doses de 12.59 e 25.10 Gy eram semelhantes, porém, quantitativamente diferentes: muito mais intensos nas doses de 25.0 Gy. Não foram evidenciadas modificações na camada de Descement. Conclusões: Os nossos resultados estão consistentes com aqueles encontrados no coelho e no homem, mas as variações observadas quanto às doses empregadas são devidas aos modelos e às condições experimentais.

Patters of nitric oxide synthase expression in the developing superior colliculus

Nitric oxide (NO) is synthesized in cells of both the central and peripheral nervous system and has been implicated in several forms of synaptic plasticity. The enzyme that produces NO, nitric oxide synthase (NOS), can be visualized in the brain by the reduced nicotinamide adenine dinucleotide phosphate diaphorase histochemistry technique (NADPH-d). We have used NADPH-d activity to detect the presence of NOS-positive cells in the developing rat superior colliculus. Our results showed that NOS is present in cells and neuropil in the developing and adult rat superior colliculus. The first NOS-positive cells appeared at postnatal day 7 and were weakly stained. The number and intensity of the NOS-positive cells increased progressively during the following days reaching a maximum at postnatal day 15. By the end of the third postnatal week, both the number and intensity of stained cells showed an adult-like pattern. The NOS-positive cells showed a Golgi-like mosphology and we have found that all cell types present in the superior colliculus express the enzyme. The expression of NOS by tectal cells parallels the functional development of the retino-collicular and cortico-tectal projections and suggest that nitric oxide synthase-positive cells might be involved in this process. In this review we highlighted some of the recent descriptions of the expression of NOS in the mammalian visual system with emphasis in the superior colliculus and correlate these findings with several developmental events taking place in this structure.