Figure 9.
Distribution of YKL-40 and von Willebrand factor in the occipital marginal zone from a 21st wpc human fetus (crown-rump length: 200 mm). The section was stained with antibodies against YKL-40 (green) and von Willebrand Factor (vWF) (red), nuclear counterstained with DAPI (blue) and viewed using confocal microscopy. The YKL-40-immunopositive end feet layer (EFL, arrows) separates the leptomeninges and underlying marginal zone. No blood vessels penetrate the marginal zone in this section. Note the strongly immunoreactive leptomeningeal cells (LMC), some of which surround the vWF-positive endothelial cells (EC) of the vessels of the pia-arachnoid. The EFL forming the outermost part of the marginal zone shows a strong membranous reactivity, with a decreasing immunoreactivity within its deeper strata. Scale bar:20 μm.