Parameters fit to the model in Eq 1, originally presented by Rahbar et al. [3].

<p>The parameters fit to each human vessel specimen in the first six columns with the mean and standard deviation of the human data in the seventh column and the mean and standard deviation of rat mesenteric vessels from Rahbar et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0183222#pone.0183222.ref003" target="_blank">3</a>] in the last column. Rahbar et al. tested vessel segments both upstream and downstream of a secondary lymphatic valve but found no statistical significance between the regions, so we chose to include only upstream data from their work.</p

Volumetric renderings of collagen and elastin layers within in the lymphatic vessel wall imaged using multiphoton microscopy.

<p>(A) Collagen signal as viewed from the interior of the vessel. (B) Elastin signal as viewed from the interior of the vessel. The bottom panels show composite renderings of collagen (white) and elastin (green) within the interior surface of the vessel (C) and the exterior surface (D). Volumetric renderings of multiphoton image data were performed using the software FluoRender [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0183222#pone.0183222.ref025" target="_blank">25</a>]. Scale bar 100 μm.</p

Isolation and biomechanical testing of cannulated vessels.

<p>(A) Example of lymphatic tissue excised during cytoreductive surgery along the retroperitoneal vessels. (B) A schematic of the experiments. The vessel was cannulated to a micropipette tip connected to a pressure reservoir at one end and an axial force transducer at the other. Transmural pressure was increased by adjusting the height of the pressure reservoir, and axial stretch was applied using a calibrated micrometer. An example of an image of a cannulated vessel can be seen in the inset. (C) Photograph of the cannulation chamber. This chamber was fixed on top of a stereo light microscope for imaging and measurement of vessel diameter.</p

Collagen and elastin orientation as quantified by FFT.

<p>The mean collagen fibre orientation from the 6 specimens is given in blue, and the mean elastin orientation is given in red. Error bars indicate standard deviation. Orientation angles from -90° to 90°, with the axial length of the vessel orientated at 0°. Asterisks indicate a significant statistical difference between collagen and elastin orientation as detected via T-test.</p