PMC

Effect of melittin (10 μg/kg) on the stomach body. (A) Transverse section in the body of the stomach of a mouse treated with melittin (10 μg/kg) for 3 days showing intense reactivity of SMA at the muscularis mucosa (arrow head) and muscularis externa (double arrow heads) (SMA immunohistochemistry, X100). (B) Transverse section in the body of the stomach of a mouse treated with melittin (10 μg/kg) for 3 days showing a high magnification of the muscularis mucosa (arrow head) and muscularis externa (double arrow heads) which displays intense reactivity with SMA (SMA immunohistochemistry, X400). (C) Transverse section in the body of the stomach of a mouse treated with melittin (10 μg/kg) for 5 days showing intense reactivity of SMA at the muscularis mucosa (arrow head) and the muscularis externa (double arrow heads) (SMA immunohistochemistry, X100). (D) Transverse section in the body of the stomach of a mouse treated with melittin (10 μg/kg) for 5 days showing an enlarged part of the previous figure in which the muscularis externa (double arrow heads) reveals intense SMA reactivity. LM: Longitudinal muscles; CM: Circular muscles (SMA immunohistochemistry, X400). (E) Transverse section in the body of the stomach of a mouse treated with melittin (10 μg/kg) for 10 days showing muscularis mucosa (arrow head) and muscularis externa (double arrow heads) that intensely reacted with SMA (SMA immunohistochemistry, X100). (F) Transverse section in the body of the stomach of a mouse treated with melittin (10 μg/kg) for 10 days showing an enlarged part of the muscularis externa (double arrow heads) and the muscular mucosa (arrow head) that intensely reacted with SMA (SMA immunohistochemistry, X400).

Varying degrees of fibrosis of the muscularis propria in coronavirus disease 2019‐associated ischaemic enterocolitis. A, Focal fibrosis of the external muscularis propria (bracket) [haematoxylin and eosin (H&E)]. B, Replacement of the external muscularis propria by an exuberant fibroblastic reaction (bracket) (H&E). C, The muscularis propria is replaced by dense fibrosis. D, A trichrome stain highlights the replacement of the external layer of the muscular wall by dense fibrosis, with residual bundles of smooth muscle in the internal layer of the muscularis propria (arrows). [Colour figure can be viewed at wileyonlinelibrary.com]

Development of the muscularis mucosae and the longitudinal layer of the muscular sheath. Cross section of day 7 (A–C), 8 (D–F), 9 (G–I) of quail embryo stained with H&E (A–H) and Bielschowsky's Silver (I). A: spinal cord (s), lung (lu), esophagus (e). B: esophageal wall consisted of folded mucosa (mu), muscular layer (c), Lung (l), liver (li) C: endodermal cells (en), distinctive circular layer of smooth muscle cells (c), aggregation of myoblasts (my) of the prospective longitudinal muscular layer. (D) Esophagus (e), heart (h), lung (lu), vertebrae (v). (E, F) The esophagus developed distinct inner circular (c) and outer longitudinal (l) muscular layers. Note aggregated mesenchymal cells (arrowheads) in the mucosal layer. (G) The esophagus had folded mucosa. (H) the esophagus exhibited distinct muscular bundles, the inner circular (c) and outer longitudinal (l) muscular layers, muscularis mucosae (mm). Mucosal folding (arrow). (I) The wall of the esophageal muscular bundles, the inner circular (c) and outer longitudinal (l), muscularis mucosae (mm). Note telocytes (arrow).

The degree of muscular connection with a subepithelial tumor as shown by endoscopic ultrasound. A Narrow muscular connection with the tumor: the diameter of the connection with the fourth layer of the tumor is <50 % of the maximal diameter of the tumor base (black arrow hyperechoic demarcation line between the tumor and the muscularis propria layer). B Wide muscular connection with the tumor: the diameter of the connection with the fourth layer is >50 % of the maximal diameter of the tumor base