Approach used to automatically measure the caliber of a selected retinal vein.

<p>(a) View of the tree shrew optic nerve head, with a line segment crossing the selected vein. (b) Green channel intensity was plotted for the selected pixels on this line segment; vein caliber was taken as the full-width-at-half-maximum of the intensity plot. (c) The resulting vein caliber measurement (<i>overlaid</i>) corresponded well to the expected vein caliber.</p

Schematic of IOP modulation system.

<p>(a) A syringe pump injected or withdrew fluid from the eye via a fine-bore needle inserted into the anterior chamber through the peripheral cornea, while a second needle connected to a pressure transducer recorded IOP. (b) Photo of system as assembled, with a cannulated enucleated porcine eye.</p

The system enabled closed-loop control of IOP, demonstrated here in an enucleated porcine eye.

<p>The system enabled closed-loop control of IOP, demonstrated here in an enucleated porcine eye.</p

Lumped parameter model of system and ocular fluid dynamics.

<p>Lumped parameter model of system and ocular fluid dynamics.</p

Retinal vein caliber increased sharply as IOP was lowered past a threshold value.

<p>(a) Retinal vein caliber was approximately constant while IOP was above 7 mmHg, increase sharply as IOP was decreased from 7 mmHg to 5 mmHg, then was approximately constant as IOP was decreased further to 3 mmHg. (b) Retinal vein in its baseline state. (c) Retinal vein in its dilated state.</p

Xenograft fluorescence correlates with luminescence.

<p>(A) Ex vivo quantitative fluorescence imaging of six right eyes from six P14 rats, all of which were injected with Y79-EGFP-luc at P0. (B) Correlation between fluorescence intensity measured from individual eyes shown in (A) and peak bioluminescence.</p

Illustration of the neonatal rat left eye, viewed from above, showing approximate injection angle and location at the lateral equator.

<p>Illustration of the neonatal rat left eye, viewed from above, showing approximate injection angle and location at the lateral equator.</p

Characterization of pathology induced by Y79-EGFP-luc retinoblastoma cell xenografts or control injections.

<p>Brightfield (A,D,G,J), green fluorescence (B,E,H,K), and OCT (C,F,I,L) imaging over a 4 week period shown. Tumors were highly vascularized (<i>white arrowheads</i>) and had well-defined edges as seen on brightfield and fluorescence imaging. OCT provided some additional depth resolution not possible with the other two modalities, although this was limited by shadowing of posterior features. OCT was also able to identify small, distinct satellite tumors growing independent of the main tumor mass (<i>red arrows</i>). Red lines indicate the OCT planes; L, lens; R, retina.</p

Characterization of a Y79 retinoblastoma cell line expressing an EGFP-luciferase fusion protein (Y79-EGFP-luc).

<p>(A) Y79-EGFP-luc cells display identical growth kinetics to the parent cell line (F-test p = 0.49). Y79-EGFP-luc data points shifted right for clarity. (B–D) Correlations between growth parameters: (B) Luminescence versus cell count; (C) Fluorescence versus cell count; (D) Fluorescence versus luminescence. Mean ± SD shown, n = 3 (some error bars are smaller than the data point size).</p

Modeling of luciferin flux from bioluminescence imaging (BLI) data reveals slowing of tumor growth over time.

<p>(A) Conventional peak luminescence imaging of xenografts in six individual animals (each animal is one colored line) shows exponential tumor growth in the majority of animals. (B) Calculated luciferin flux () modeled (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0099036#pone.0099036.e009" target="_blank">Equations 1</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0099036#pone.0099036.e016" target="_blank">3</a>) from BLI data over the 14-day study. (C) Pseudo-color parametric images of for three representative animals at three timepoints, color-coded as in (A).</p