Twenty-four-hour monitoring of IOP frequently led to a change of glaucoma management by identifying IOP fluctuations and spikes. High IOP and wide diurnal IOP variation are considered major risk factors for glaucoma progression, and standard clinic follow-up evaluations failed to identify these phenomena.
Combating myeloid cell-mediated destruction of the retina during inflammation or neurodegeneration is dependent on the integrity of homeostatic mechanisms within the tissue that may suppress T cell activation and their subsequent cytokine responses, modulate infiltrating macrophage activation, and facilitate healthy tissue repair. Success is dependent on response of the resident myeloid-cell populations [microglia (MG)] to activation signals, commonly cytokines, and the control of infiltrating macrophage activation during inflammation, both of which appear highly programmed in normal and inflamed retina. The evidence that tissue CD200 constitutively provides down-regulatory signals to myeloid-derived cells via cognate CD200-CD200 receptor (R) interaction supports inherent tissue control of myeloid cell activation. In the retina, there is extensive neuronal and endothelial expression of CD200. Retinal MG in CD200 knockout mice display normal morphology but unlike the wild-type mice, are present in increased numbers and express nitric oxide synthase 2, a macrophage activation marker, inferring that loss of CD200 or absent CD200R ligation results in "classical" activation of myeloid cells. Thus, when mice lack CD200, they show increased susceptibility to and accelerated onset of tissue-specific autoimmunity.
During retinal degeneration, microglia are activated and express sialoadhesin. The temporal relationship between photoreceptor apoptosis and microglial response suggests that microglia are not responsible for the initial wave of photoreceptor death, and this is corroborated by the absence of iNOS and nitrotyrosine. Expression of sialoadhesin may indicate blood-retinal barrier breakdown, which has immune implications for subretinal gene therapeutic strategies.
Background/aim: Nestin is an intermediate filament marker for neural progenitor cells. The authors aimed to identify nestin positive cells in adult human retina and within surgically removed epiretinal membranes. Methods: Adult human retina and epiretinal membranes were studied. Tissue was fixed and processed for semithin sections or whole mount preparations for immunohistochemical detection of nestin and glial fibrillary acidic protein (GFAP) expression. Results: Nestin positive cells are most prominent at the ora serrata, possess fibrillary processes, small amounts of perinuclear cytoplasm, and are arranged radially within or superficially on the retina. In the posterior retina, speckled cytoplasmic nestin staining is seen around the nuclei of neurons. In the peripapillary retina most of the cells in the retinal ganglion cell layer are nestin positive. These cells appear to represent nestin positive neurons. Speckled cells are also seen in the myelinated portion of the optic nerve. In epiretinal membranes patches of elongated nestin positive cells were found. These cells were also positive for GFAP. Conclusions: Some neurons and glia in the adult human retina are nestin positive. Their pattern in anterior retina suggests an analogy with the ciliary marginal zone found in many other species. The role of these cells in pathological responses to retinal disease is suggested by the presence of large numbers of ectopic nestin positive cells in epiretinal membranes. The authors hypothesise that nestin positive cells represent a population of progenitor cells from normal adult human retina that differentiate to make up retinal scar tissue.
Objective
To report findings in asymptomatic family members of patients with macular telangiectasia type 2.
Design
Prospective, observational, cross-sectional case series.
Participants
Four patients with symptomatic macular telangiectasia type 2 (index patients) and 5 relatives, including 2 sets of monozygotic twins.
Methods
Screening of family members of participants in a non-interventional natural history study of macular telangiectasia type 2. Ophthalmologic examination included best-corrected visual acuity testing, fundus biomicroscopy, fluorescein angiography (FA), optical coherence tomography (OCT), and fundus autofluorescence (FAF) imaging.
Main Outcome Measures
Evidence for macular telangiectasia type 2 in any of the imaging methods used and visual function of the family members studied.
Results
In the first family, 2 of 3 daughters of a severely affected 68-year-old woman had features of macular telangiectasia type 2. Although one of the daughters was diagnosed by biomicroscopic examination, the second daughter was diagnosed only by subtle changes on OCT and FAF imaging. Both affected daughters were asymptomatic and were unaware that they had the condition. In the second family, clinical examination showed that the 60-year-old brother of the 75-year-old index patient obviously was affected, despite a lack of any subjective visual dysfunction. The 65-year-old monozygotic twin of the third index patient showed a slight retinal thinning within a small area temporal to the foveola in both eyes as well as minor staining on FA and a subtle monocular loss of macular pigment. The 56-year-old asymptomatic monozygotic twin of the last proband had opacification of the retina with leakage on FA in the right eye. The fellow eye was unremarkable except for an abnormal FAF signal that was present in both eyes.
Conclusions
Macular telangiectasia type 2 may be more common than previously assumed, but patients may not seek ophthalmic care if their visual function is normal. The study of these early, asymptomatic cases may yield valuable insights into the pathogenesis of the condition. Further research is warranted to determine whether there is an underlying, dominantly inherited genetic abnormality in macular telangiectasia type 2 of variable penetrance and expressivity.
These results confirm that vitrectomy substantially increases vitreous pO2. MRI is a noninvasive technique that can be used to study vitreous oxygenation in both vitrectomized and nonvitrectomized eyes.
This case series reinforces the importance of considering syphilis in the differential diagnosis of many ocular presentations, but in particular retinitis. Retinitis appears to be the predominant presentation in HIV-infected individuals, suggesting that HIV infection may somehow modulate the disease.
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