In situ versus whole-globe harvesting of corneal tissue from remote donor sites: effects on initial tissue quality.

PURPOSE: There are 2 methods of corneal tissue procurement currently in widespread use: in situ extraction of the corneal button directly to preservation media and whole-globe enucleation of eyes with removal of the button to preservation media at a later time. This study evaluates the effects of these 2 procurement procedures on the initial quality of donor corneal tissue. METHODS: Slit-lamp examination results and endothelial cell counts were compared for a total of 468 donor corneas harvested at 2 remote locations: one where in situ procurement was practiced and the other that used whole-globe enucleation procedures. RESULTS: In both univariate and multivariate analysis, in situ corneas were found to have a lower incidence of moderate or severe haze and folds in Descemet membrane. No differences in mean endothelial cell counts were noted between the 2 populations of donated tissue. CONCLUSIONS: In situ procurement of corneal tissue results in higher initial corneal tissue quality than whole-globe procedures.

Molecular genetic analysis of the Idd4 locus implicates the IFN response in type 1 diabetes susceptibility in nonobese diabetic mice.

High-resolution mapping and identification of the genes responsible for type 1 diabetes (T1D) has proved difficult because of the multigenic etiology and low penetrance of the disease phenotype in linkage studies. Mouse congenic strains have been useful in refining Idd susceptibility loci in the NOD mouse model and providing a framework for identification of genes underlying complex autoimmune syndromes. Previously, we used NOD and a nonobese diabetes-resistant strain to map the susceptibility to T1D to the Idd4 locus on chromosome 11. Here, we report high-resolution mapping of this locus to 1.4 megabases. The NOD Idd4 locus was fully sequenced, permitting a detailed comparison with C57BL/6 and DBA/2J strains, the progenitors of T1D resistance alleles found in the nonobese diabetes-resistant strain. Gene expression arrays and quantitative real-time PCR were used to prioritize Idd4 candidate genes by comparing macrophages/dendritic cells from congenic strains where allelic variation was confined to the Idd4 interval. The differentially expressed genes either were mapped to Idd4 or were components of the IFN response pathway regulated in trans by Idd4. Reflecting central roles of Idd4 genes in Ag presentation, arachidonic acid metabolism and inflammation, phagocytosis, and lymphocyte trafficking, our combined analyses identified Alox15, Alox12e, Psmb6, Pld2, and Cxcl16 as excellent candidate genes for the effects of the Idd4 locus.

AII amacrine cells express the MT1 melatonin receptor in human and macaque retina.

AII amacrine cells are critical interneurons in the rod pathway of mammalian retina, active primarily in dim lighting conditions. Melatonin, a neuromodulator produced at night in the retina, is believed to induce retinal adaptation to dim lighting conditions in most vertebrate species examined to date, including humans. We hypothesized that melatonin may influence retinal light adaptation by acting on AII cells directly and thus investigated whether melatonin receptors were expressed in AII neurons. Postmortem nonpathological eyes from four human donors as well as two eyes from two Macaque Fasicularis monkeys were analyzed. Double immunocytochemistry was performed using an anti-MT(1) antibody and an antibody to calretinin, an AII marker. Analysis utilized confocal microscopy. A polyclonal anti-calretinin antibody labelled amacrine cells exhibiting the distinct AII morphology, in both human and macaque retina. MT(1) immunoreactivity in macaque retina was similar to human staining, in that horizontal, amacrine and ganglion cell bodies were stained, as were inner segments of photoreceptors. In human retina 86% of calretinin positive cells expressed the MT(1) receptor peripherally, whereas centrally, 78% colocalization was observed. In the macaque retina, 100% of AII amacrine cells expressed MT(1) immunoreactivity both centrally and peripherally. That virtually all AII neurons express the MT(1) receptor in both human and macaque retina, may provide the first evidence demonstrating a role for melatonin in AII regulation, furthering the hypothesis of melatonin function in retinal light adaptation.

MT(1) melatonin receptor in the human retina: expression and localization.

PURPOSE: Melatonin's function in human vision is far from understood, in part because of the lack of information on its cellular targets. Therefore, expression and localization of the MT(1) melatonin receptor in human retina was examined. METHODS: Postmortem nonpathologic human eyes from nine donors were investigated, three by reverse transcription-polymerase chain reaction (RT-PCR) for MT(1) and MT(2) transcripts and six by immunocytochemistry, using a peptide-specific anti-MT(1) receptor antibody. RESULTS: RT-PCR suggested that both MT(1) and MT(2) transcripts had similar levels of expression. Vertical slices of human retina demonstrated MT(1) immunoreactivity in cell bodies along the outer border of the inner nuclear layer (INL), along the inner border of the INL, in cell bodies within the ganglion cell layer (GCL), and in the inner segments (IS) of photoreceptors. Double immunolabeling using anti-MT(1) and tyrosine hydroxylase revealed that 69% of CA1 and 63% of CA2 dopaminergic neurons exhibited MT(1) immunoreaction. Double immunolabeling with anti-parvalbumin, a horizontal cell marker, showed that MT(1)-positive cells along the outer INL border were exclusively horizontal cells, and that 18% of horizontal cells in central retina expressed MT(1). Double staining with MT(1) and markers for both rod and cone photoreceptors suggest that IS staining is present on rod cells. CONCLUSIONS: The MT(1) receptor is expressed in diverse neuronal cell types in the human retina, providing evidence of a significant role for melatonin and this receptor subtype in human vision.