Figure 1. Syncytial knots. Third trimester placenta chorionic villi with many syncytial knots (arrows). Syncytial knots are collections of large numbers of syncytial trophoblast nuclei localized to a single region of the villous surface, sometimes forming bulges in the syncytial trophoblast layer. Hematoxylin and eosin staining.

 Figure 2. CRH expression in the hypothalamus. Human hypothalamus was stained with anti-CRH antibodies (A, B) or with non-immune mouse ascites (NMA) as a negative control (C, D). A) Scattered, specific neuron bodies contain CRH (arrowheads). Other neurons are negative, showing the specificity of the anti-CRH antibody. B) Same as A. Note axon of one of the CRH positive neurons (arrow). C, D) Serial sections stained with NMA show no staining.

Figure 3. CRH only stains the syncytial knots of the chorionic villi. Third trimester placenta chorionic villi stained with anti-CRH antibody. A) Prominent CRH positive syncytial knot (red arrow) containing many nuclei is seen in the center of the field. The syncytium near this knot contains some CRH (orange arrowheads), possibly due to diffusion within the contiguous syncytial trophoblast cytoplasm. Syncytial trophoblasts not adjacent to the positive knot are negative (pink arrows). B, C) CRH positive syncytial knots (red arrows) with surrounding negative syncytium (pink arrows). D) Higher power view of large polyp-like syncytial knot that is strongly CRH positive (red arrows). The nearby syncytium is only lightly stained or negative for CRH (pink arrows).