Ultrastructural changes in the smooth musculature of antrum and pylorus in presence of ulcus ventriculi

Abstract

Summary. The smooth musculature of antrum and pylorus of 7 patients with one or more stomach ulcers was examined by transmission electron microscopy. Corresponding regions of the stomachs of 5 normal organ donors served as control material.EleetronmieroseopieMly visualizable changes were found at distances of up to 180 mm from the site of ulcerous lesion on the smooth muscle cells of the inner eireular and outer longitudinal musculature, also on the blood vessels.A regularly occurring modification of the smooth muscle cells of antrum and pylorus consists of a structural condensation of the nucleus, of the sare0plasmie ground substance and of the myofilaments, combined with augmentation and distension of the hypolemmal vesicles and of the dense bodies. These findings are interpreted as expression of a pronounced isometric contraction of the smooth musculature in the antrum and pylorus in presence of uleera ventrieuli. Such findings are not obtainable on normal material.Besides pathological modifieations at the smooth muscle cells which are unspecific for stomach ulcer, such as accumulation of lipofusein in the endoplasm~tie lacunae and lysis of the myofilaments, specific changes were observed. These eoneern the interstiees of the endoplasmie retieulum to be found only in the endoplasmatic lacunae. In numerous muscle cells of the circular and longitudinal muscle layers an extremely marked distension of the endoplasmie retieulum is found. Vaeuolization of the endoplasmie eisternae causes displacement of the other cell organelles and of the myofilaments.The capillary endothelial cells show degenerative changes which bring about arrest of eytopemptie processes. In the arteriolar regions a strong contraction of the smooth musculature, at times resulting in complete occlusion of the vasal lumen, is frequently found. These findings, too, are obtainable only on stomachs with uleera ventrieuli and not on normal control material.