Time course modifications in organotypic culture of human neuroretina

The purpose of this study was to characterize organ culture of human neuroretina and to establish survival and early degeneration patterns of neural and glial cells. Sixteen neuroretina explants were prepared from 2 postmortem eyes of 2 individuals. Four explants were used as fresh retina controls, and 12 were evaluated at 3, 6, and 9 days of culture. Neuroretina explants (5 × 5 mm) were cultured in Transwell® dishes with the photoreceptor layer facing the supporting membrane. Culture medium (Neurobasal A-based) was maintained in contact with the membrane beneath the explant. Cryostat and ultrathin sections were prepared for immunohistochemistry and electron microscopy. Neuroretinal modifications were evaluated after toluidine blue staining and after immunostaining for neuronal and glial cell markers. Ultrastructural changes were analyzed by electron microscopy. From 0 to 9 days in culture, there was progressive retinal degeneration, including early pyknosis of photoreceptor nuclei, cellular vacuolization in the ganglion cell layer, decrease of both plexiform layer thicknesses, disruption and truncation of photoreceptor outer segments (OS), and marked reduction in the number of nuclei at both nuclear layers where the cells were less densely packed. At 3 days there was swelling of cone OS with impairment of pedicles, loss of axons and dendrites of horizontal and rod bipolar cells that stained for calbindin (CB) and protein kinase C (PKC-α), respectively. After 9 days, horizontal cells were pyknotic and without terminal tips. There were similar degenerative processes in the outer plexiform layer for rod bipolar cells and loss of axon terminal lateral varicosities in the inner plexiform layer. Glial fibrillary acidic protein (GFAP) staining did not reveal a dramatic increase of gliosis in Müller cells. However, some Müller cells were CB immunoreactive at 6 days of culture. Over 9 days of culture, human neuroretina explants underwent morphological changes in photoreceptors, particularly the OS and axon terminals, and in postsynaptic horizontal and bipolar cells. These early changes, not previously described in cultured human samples, reproduce some celullar modifications after retinal damage. Thus, this model may be suitable to evaluate therapeutic agents during retinal degeneration processes.

A seriation of the late prehistoric Santa Maria culture of northwestern Argentina / Ronald L. Weber, Field Museum of Natural History.

v.68:no.2(1968)

Material culture of the Chilcotin Athapaskans of west central British Columbia : collections in the Field Museum of Natural History / James W. VanStone.

n.s. no.20(1993)

Material culture of the Blackfoot (Blood) Indians of southern Alberta / James W. VanStone.

n.s. no.19(1992)

In Pursuit of Peace, Prosperity and Power – What ASEAN and EU can learn from each other? EU Centre Singapore Policy Brief No. 7, May 2014

The EU and ASEAN are often compared and seen as relatively successful regional organisations in their respective regions. Yet of late, both regional organisations are under intense scrutiny as they confront challenges posed by the financial crisis and rising geopolitical tensions. Their inability to respond effectively to these challenges has brought about a chorus of criticisms. Noting the current tensions face by both the EU and ASEAN in their respective regions, one could not help but wonder how and if they would be able to deal with the increasing complex security landscape because of a weakened US, and the rise of the rest. This article will compare and contrast the approaches taken by the EU and ASEAN thus far in trying to build peace and prosperity, and how they manage the demands of power politics to distill some lessons on what they can learn from each other in order to navigate an increasingly paradoxical world of economic interdependence but political fragmentation.

Report of the Delegation of the United States of America to the Inter-American Conference for the Maintenance of Peace,

Cordell Hull, chairman.