Table 2.

Percent distribution, average widths and period of helicity of each fibril morphology from CSA Type 2, 3 and 4 mice

	Type 2	Type 3	Type 4
% Straight fibrils	24.6%	87.0%	96.2%
Average width (nm)	22.47 ± 2.97	19.53 ± 3.45	19.24 ± 2.93
Average period of helicity (nm)	–	–	–
% Coiled fibrils	44.6%	1.6%	–
Average width (nm)	22.77 ± 1.83	20.43 ± 1.80	–
Average period of helicity (nm)	95.85 ± 9.39	92.59 ± 3.94	–
% Twisted ribbon-like fibrils	12.3%	1.3%	–
Average width (nm)	19.96 ± 1.46	23.65 ± 3.39	–
Average period of helicity (nm)	146.12 ± 5.86	134.97 ± 8.47	–
% Other	16.9%	10.1%	3.8%

The distribution of each fibril morphology was calculated from the fibril counts. Type 2 samples contain all three fibril morphologies, with coiled fibrils being the predominant form (n = 65). Type 3 samples contain a high proportion of straight fibrils, although coiled and twisted ribbon fibrils are still present (n = 553). Type 4 samples are exclusively composed of straight fibrils (n = 598). ‘Other’ refers to fibrils which were obscured or did not fit into the other morphologies. The width of fibrils were measured and found to be consistent across all fibril morphology regardless of CSA Type. In contrast, the period of helicity differed between twisted ribbon-like and coiled fibrils, with twisted ribbon-like fibrils having a longer helical period. Helicity measurements were not possible for straight fibrils as they do not display a visible crossover region. Width and helicity measurements were made in Adobe Photoshop using the ‘Ruler’ tool