RESUMO
Mice express S and M opsins that form visual pigments for the detection of light and visual signaling in cones. Here, we show that S opsin transcription is higher than that of M opsin, which supports ultraviolet (UV) sensitivity greater than midwavelength sensitivity. Surprisingly, most cones coexpress both S and M opsins in a common cone cell type throughout the retina. All cones express M opsin, but the levels are graded from dorsal to ventral. The levels of S opsin are relatively constant. However, in the far dorsal retina, S opsin is repressed stochastically, such that some cones express M opsin only. These observations indicate that two different mechanisms control M and S opsin expression. We suggest that a common cone type is patterned across the retinal surface to produce phenotypic cone subtypes.
Assuntos
Retina/metabolismo , Células Fotorreceptoras Retinianas Cones/metabolismo , Opsinas de Bastonetes/biossíntese , Animais , Contagem de Células , Imuno-Histoquímica , Hibridização In Situ , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Microscopia Confocal , Dados de Sequência Molecular , Especificidade de Órgãos , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Retina/citologia , Células Fotorreceptoras Retinianas Cones/citologia , Células Fotorreceptoras Retinianas Bastonetes/citologia , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , Opsinas de Bastonetes/genética , Especificidade da EspécieRESUMO
BACKGROUND: Age-related macular degeneration (AMD) is a common cause of severe vision loss in people 55 years and older. OBJECTIVES: The objective of this review was to investigate the effects of anti-VEGF (vascular endothelial growth factor) modalities for treating neovascular AMD. SEARCH STRATEGY: We searched CENTRAL, MEDLINE, EMBASE and LILACS. We handsearched ARVO abstracts for 2006, 2007 for ongoing trials. SELECTION CRITERIA: We included randomized controlled trials (RCTs). DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data. We contacted trial authors for additional data. We summarized outcomes as relative risks (RR), number needed to treat (NNT) and weighted mean differences. MAIN RESULTS: We included five RCTs of good methodological quality. All five trials were conducted by pharmaceutical companies. An intention-to-treat analysis using the last observation carried forward method was done in most trials. Two trials compared pegaptanib versus sham. One trial compared ranibizumab versus sham, another compared ranibizumab/sham verteporfin PDT versus verteporfin PDT/sham ranibizumab, and the final trial compared ranibizumab plus verteporfin PDT versus verteporfin PDT alone. Fewer patients treated with pegaptanib lost 15 or more letters of visual acuity at one year follow-up compared to sham (pooled relative risk (RR) 0.71; 95% confidence interval (CI) 0.61 to 0.84). The NNT was 6.67 (95% CI 4.35 to 14.28) for 0.3 mg pegaptanib, 6.25 (95% CI 4.17 to 12.5) for 1 mg pegaptanib and 14.28 (95% CI 6.67 to 100) for 3 mg pegaptanib. In a trial of ranibizumab versus sham, RR for loss of 15 or more letters visual acuity at one year was 0.14 (95% CI 0.1 to 0.22) in favour of ranibizumab. The NNT was 3.13 (95% CI 2.56 to 3.84) for 0.3 mg ranibizumab and 3.13 (95% CI 2.56 to 3.84) for 0.5 mg ranibizumab. In a trial of ranibizumab versus verteporfin PDT, RR for loss of 15 or more letters at one year was 0.13 (95% CI 0.07 to 0.23) favouring ranibizumab. The NNT was 3.33 (95% CI 2.56 to 4.76) for 0.3 mg ranibizumab and 3.12 (95% CI 2.43 to 4.17) for 0.5 mg ranibizumab. In another trial of combined ranibizumab plus verteporfin PDT versus verteporfin PDT, RR for loss of 15 or more letters at one year favoured combined therapy (RR 0.3 (95% CI 0.15 to 0.60). The NNT was 4.35 (95% CI 2.78 to 11.11). Pooled RR for gain of 15 or more letters visual acuity at one year was 5.81 (95% CI 3.29 to 10.26) for ranibizumab versus sham, 6.79 (95% CI 3.41 to 13.54) for ranibizumab/sham verteporfin PDT versus verteporfin PDT/sham ranibizumab, and 4.44 (95% CI 1.40 to 14.08) for ranibizumab plus verteporfin PDT versus verteporfin PDT. Frequency of endophthalmitis in included studies was between 0.7% to 4.7% with ranibizumab and 1.3% with pegaptanib. Improvement in vision-specific quality of life was reported for both treatments. AUTHORS' CONCLUSIONS: Pegaptanib and ranibizumab reduce the risk of visual acuity loss in patients with neovascular AMD. Ranibizumab causes gains in visual acuity in many eyes. Quality of life and cost will be important for treatment decisions. Other agents blocking VEGF are being tested in ongoing trials.
Assuntos
Inibidores da Angiogênese/uso terapêutico , Degeneração Macular/tratamento farmacológico , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Idoso , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Humanizados , Aptâmeros de Nucleotídeos/uso terapêutico , Neovascularização de Coroide , Humanos , Pessoa de Meia-Idade , Porfirinas/uso terapêutico , Ensaios Clínicos Controlados Aleatórios como Assunto , Ranibizumab , VerteporfinaRESUMO
PURPOSE: To illustrate succinctly the various stages of macular hole formation. METHOD: We photodocumented the evolution of a full-thickness macular hole in a patient who refused surgery. RESULTS: A 60-year-old woman, who had had difficulty reading for 3 months, was initially examined with a stage 1B macular hole in her right eye that progressed to stage 2 over a 6-month period and then to stage 3, 2 years after initial examination. CONCLUSIONS: This case demonstrates vividly and succinctly the development of a full-thickness macular hole from stage 1B to stage 3 and provides a unique opportunity to study carefully in a single eye the sequential progression of this important retinal disorder.