Different-sized extracellular vesicles derived from stored red blood cells package diverse cargoes and cause distinct cellular effects.

Background: The formation of extracellular vesicles (EVs) occurs during cold storage of RBCs. Transfusion of EVs may contribute to adverse responses in recipients receiving RBCs. However, EVs are poorly characterized with limited data on whether distinct vesicles are formed, their composition, and potential biological effects.

A Novel Tree Shrew (Tupaia belangeri) Model of Glaucoma.

Purpose: Primates and rodents are used widely as animal models of glaucoma, but each has significant limitations. Researchers need additional animal models that closely resemble the relevant anatomy and pathologic features of the human disease to more quickly advance research. We validate a novel glaucoma animal model in tree shrews (Tupaia belangeri).

Effects of particulates and lipids on the hydraulic conductivity of Matrigel.

The hydraulic conductivity of a connective tissue is determined both by the fine ultrastructure of the extracellular matrix and the effects of larger particles in the interstitial space. In this study, we explored this relationship by examining the effects of 30- or 90-nm-diameter latex nanospheres or low-density lipoproteins (LDL) on the hydraulic conductivity of Matrigel, a basement membrane matrix. The hydraulic conductivity of Matrigel with latex nanospheres or LDL particles added at 4.

Reprogramming progeny cells of embryonic RPE to produce photoreceptors: development of advanced photoreceptor traits under the induction of neuroD.

Purpose: In examining the prospect of producing functional photoreceptors by reprogramming the differentiation of RPE progeny cells, this study was conducted to investigate whether reprogrammed cells can develop highly specialized ultrastructural and physiological traits that characterize retinal photoreceptors.

Methods: Cultured chick RPE cells were reprogrammed to differentiate along the photoreceptor pathway by ectopic expression of neuroD. Cellular ultrastructure was examined with electron microscopy.

Prevalence and morphology of druse types in the macula and periphery of eyes with age-related maculopathy.

Purpose: Macular drusen are hallmarks of age-related maculopathy (ARM), but these focal extracellular lesions also appear with age in the peripheral retina. The present study was conducted to determine regional differences in morphology that contribute to the higher vulnerability of the macula to advanced disease.

Methods: Drusen from the macula (n = 133) and periphery (n = 282) were isolated and concentrated from nine ARM-affected eyes.

Comparison of morphology of human macular and peripheral Bruch's membrane in older eyes.

Deposits in macular human Bruch's membrane (BrM) increase with age and have been postulated to be associated with age-related maculopathy. We used two ultrastructural methods to compare these deposits by electron microscopy in macular and peripheral BrM of eight eyes from donors 63-86 years of age. Quick-freeze/deep-etch (QFDE) was used to prepare replicas that showed the ultrastructure of deposits, and osmium-tannic acid-paraphenylenediamine (OTAP) was used to preserve small extracellular lipid particles.

Age-related changes in human macular Bruch's membrane as seen by quick-freeze/deep-etch.

Lipid-containing inclusions have been observed in human Bruch's membrane (BrM) and are postulated to be associated with age-related maculopathy (ARM), a major cause of legal blindness in developed countries. The dehydration associated with specimen preparation for thin-section transmission electron microscopy causes loss of these inclusions. Better preservation of the ultrastructure of the inclusions and tissue is achieved by using a quick-freeze/deep-etch preparation.

Apolipoprotein localization in isolated drusen and retinal apolipoprotein gene expression.

Purpose: To evaluate apolipoprotein (Apo) gene expression in native human retinal pigment epithelium (RPE) and neurosensory retina and to detect apolipoproteins within age-related, extramacular drusen.

Method: Drusen were isolated manually from 10 eyes of 10 donors (age range, 58-93 years) with grossly normal maculas that were preserved in 4% paraformaldehyde within 6 hours of death. In cryosections of druse-enriched pellets (6-57 drusen per eye), the Apos A-I, A-II, B, C-I, C-II, C-III, E, and J were detected by indirect immunofluorescence.

Synaptic input to the on-off directionally selective ganglion cell in the rabbit retina.

A physiologically identified on-off directionally selective (DS) ganglion cell with its preferred-null axis defined was stained with horseradish peroxidase (HRP) and prepared for electron microscopy. A continuous series of thin sections were used to examine the cell's synaptology. Although the DS cell dendrite received the majority of its synaptic input from a heterogeneous population of amacrine cell processes, a frequently observed synaptic profile consisted of a DS cell dendrite receiving synapses from a cluster of several amacrine cell processes.