Histochemical study of the mucosubstances in the canine stomach. I. The resting mucosa

Histochemical staining and characterization of glycoproteins in Acid-secreting cells of frog stomach

Glycoproteins were histochemically localized in oxyntic cells of the frog stomach by staining with periodic acid-silver methenamine. Reduction of silver was most intense on (a) the outer aspect of the apical plasmalemma, (b) within the tubular smooth membrane system characteristic of oxyntic cells, and (c) within cisternae and vesicles of the Golgi complex. Other membrane components such as those from the mitochondria, nucleus, junctional complex, lateral and basal cell membranes showed little or no stainability. Gastric mucosal homogenates were fractionated by centrifugation for further morphological and chemical analysis. The staining reaction of the microsomal fraction (40,000 g x 60 min) was similar to that of the tubular membranous components of intact oxyntic cells. Carbohydrate analyses showed that all cell fractions are extremely low in acidic sugars, uronic and sialic acids, while neutral sugars and hexosamines are relatively abundant. The microsomal fraction contains the largest proportion of carbohydrates, ca. 9% of the fat-free dry weight. Another distinguishing feature is that glucosamine is the only detectable hexosamine in the microsomal fraction. These histochemical and chemical data indicate that neutral glycoproteins are associated with membranous components which have been implicated in the process of HCl secretion by oxyntic cells. The staining pattern within the cells supports the hypothesis of interrelationships between the Golgi membranes, tubular smooth membranes, and apical surface membrane.

Distribution of mucins in the mucosa of the digestive tract of reptiles: a histochemical study

In the present study, the distribution and characteristics of mucins in the digestive tract of 3 reptiles (Lacerta lepida, Mauremys caspica and Testudo graeca) are investigated. In the esophagus of Testudo graeca, both the glands and the mucous cells of the surface epithelium contained sulphosialo-mucins. In Lacerta lepida, esophageal mucous cells contained either-sialo-mucins or sulphosialo-mucins. The esophageal mucous cells of Mauremys caspica contained acidic mucosubstances. The stomach of the species studied revealed a small amount of acidic mucosubstances; in Lacerta lepida and Testudo graeca, abundant neutral mucins were detected. In the intestine, the amount of acidic mucosubstances was increased in a caudal direction, the sulphosialo-mucins being predominant. In conclusion, acid mucins were more abundant in the esophagus and intestine than in the stomach. This may be related to cytoprotective roles in the esophagus and protection against potential pathogens in the intestine.

Uremic gastropathy in the dog

Stomachs of four dogs with uremia and four normal dogs were examined. Uremic stomachs represented four types of disease: atrophic, amyloidotic, ulcerative and necrotic gastropathy. Pathologic changes common to all uremic stomachs were expansion of the lamina propria, atrophy of gastric glands, and submucosal arteriopathy; lesions were limited to body and fundic zones. Lamina propria was markedly expanded by edema, mastocytosis, deposition of acidic mucosubstances, fibroplasia and mineralization. Capillaries in lamina propria had swollen endothelium and calcium salts were present extracellularly as amorphous granular laminae. Gastric glands were distorted and irregular and had fewer cells per unit of tissue. Parietal cells were swollen and had fragmentation of cytocavitary network and mitochondrial swelling with calcification. Chief cells were shrunken, agranular and atrophic with foci of glycogen and dilation of endoplasmic reticulum. Argentaffin cell content was diminished. Muscular arteries of submucosae had segmental degenerative lesions characterized by myocyte necrosis, calcification, and deposition of acidic mucosubstances and fibrin; thrombosis and obstructive arteriopathy were common. These studies suggest that uremic gastropathy is a disease of mucosal lamina propria and that lesions were due to anoxia caused by diffuse vascular injury and to altered parietal cell function.

Mucosubstance histochemistry of Brunner's glands, pyloric glands and duodenal goblet cells in the ferret

The mucosubstance of Brunner's glands, pyloric glands and duodenal goblet cells were studied using the various histochemical methods. The secretions of both Brunner's and pyloric glands were similar in their histochemical reactions. They contained neutral mucosubstances as in these glands in man. The duodenal goblet cells showed variations in their histochemical characters. (i) The secretions of most of the deep cells and the majority of superficial cells contained sialidase-labile and sialidase-resistant sialomucins. (ii) There were a few superficial and occasional deep cells, the secretions of which contained sulphated mucosubstances. (iii) There were some goblet cells, more in the villi than in the crypts, the secretions of which contained a mixture of sialomucins and a sulphated mucin. The sialomucin was mostly sialidase-labile and partly sialidase-resistant.

Comparative histochemistry of gastrointestinal mucosubstances

Two histochemical sequential staining techniques, Alcian blue-PAS (AB-PAS) and high-iron-diamine-Alcian blue (HID-AB), which differentiate neutral from sulfated and non-sulfated acid mucosubstances, were applied to sections from the gastrointestinal tract of eleven mammalian species, including man, to study patterns of distribution of gastrointestinal epithelial mucosubstances. The application of these techniques under uniform laboratory conditions enabled a detailed description of epithelial mucosubstances throughout the gastrointestinal tract relative to location in each species as well as a comparison of their distribution among various species. The results showed that all of the 11 species studied had a distinctly different distribution of epithelial mucosubstances throughout the entire gastrointestinal tract. These differences were most obvious in the stomach and duodenum. In each species, neutral mucosubstances were most evident in the stomach and acid mucosubstances in the intestines, with sulfomucins most prominent in the large bowel. Acid mucosubstances were noted in Paneth cell granules of rodent species only. These histochemical observations make available a uniform comparative basis for the normal distribution of mammalian gastrointestinal mucosubstances which should facilitate their study in diverse pathological conditions.