Ultrastructure of duodenal endocrine cells in children

All ultrastructural varieties of endocrine cells, described in literature for adult persons, were revealed in the epithelium of the duodenal crypts of children at the age of 6--14 years. The cells form rather distinct groups in accordance with the International Classification, that speaks in favour of adequate application of the methods for processing the material and allows to compare the data obtained with those in literature. Endocrine cells in children, however, demonstrate greater polymorphism as their secretory granules differ in density even within a single cell. This phenomenon, along with detecting degenerative forms, demonstrates active functioning of this cell system in children.     

The endocrine cells of the pyloric glands of adult ox

As part of a project to identify the endocrine cells ("EC" and "APUD" series) of the gastroenteric apparatus of ruminants, the ultrastructure of the mucosa of the pyloric glands of adult ox was studied morphologically and cytochemically, in parallel with a light microscope histochemical analysis. The results show that: the "EC" cells (producing 5-HT) are recognizable by their secretory granules which are heavily osmiophilic, argentaffin ("Masson") and argyrophilic ("Grimelius"). A further distinction is possible on the basis of their morphological features: the "EC" cells of the gastric type (which belong to the "ECn" group) contain granules fairly homogeneous in shape and size, while the "EC" cells of the intestinal type (or "EC1") show granules which are more pleiomorphic and variable in size. Of particular interest is the presence in some cells of granules typical of the "EC" cells of the intestinal type, in the vicinity of a few others, which appear quite similar to those of the adjoining exocrine cells; the "G" cells (gastrin producing) contain medium sized granules, which are unreactive to "Masson" and poorly argyrophilic. Their morphology is rather diverse; some of them (these are the "typical" cells) have a granular and weakly electron dense content, others (which we consider "atypical") show a homogeneous and heavily osmiophilic core, with an eccentrical empty area. Also present are granules whose appearance is intermediate and empty vesicles; the "D cells" (somatostatin producting) show round, medium sized granules which have a granular, moderately osmiophilic core, tightly encircled by the membrane. These granules are unreactive to "Masson" and to "Grimelius"; the "D1" cells (whose function is yet unclear) contain small, round granules whose core is variously but discretely electron dense and not always homogeneous; they are unreactive to "Masson" and fairly argyrophilic. These granules may be numerous and packed, or scarce; in this latter instance the few granules are intermingled with variously running tufts of parallel filaments, thus resembling the "P" cells, whose function is still undefined. These data show therefore that the types of endocrine cells we have identified in the pyloric glands of adult ox correspond to those described in other mammals; "X" and "F" or "PP" cell appear to be lacking.     

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.     

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

Summary 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 sialomycins and a sulphated mucin. The sialomucin was mostly sialidase-labile and partly sialidase-resistant.     

Proliferative activity of gastric and duodenal endocrine cells in the rat

The replicative activity and migration of gastrin, somatostatin and serotonin cells in rat stomach and duodenum was studied using combined immunocytochemistry and autoradiography after 3H thymidine pulse-labeling. Our results show that a small proportion of gastrin, somatostatin and serotonin immunoreactive cells displays proliferative activity. The overall labeling index ranged from 1.3% for gastric endocrine cells to 3.2% for duodenal endocrine cells. In a pulse chase experiment, labeling indices of immunoreactive cells were estimated at several time intervals after 3H thymidine administration. Significant differences in labeling index were not found. Migration of 3H thymidine labeled endocrine cells towards the luminal surface was not found in the stomach nor in the duodenum. It is concluded that 1) these endocrine cells have replicating activity; 2) the replicative activity of endocrine cells is higher in the duodenum than in the stomach; 3) the various cell types do not show significant differences in replicating activity and 4) endocrine cells did not seem to migrate to the luminal surface of the mucosa along with the other epithelial cells.     

Ultrastructural and cytochemical studies on the cytodifferentiation of duodenal endocrine cells

Summary The development and cytodifferentiation of endocrine cells that produce the gastrointestinal hormones gastrin, cholecystokinin and secretin have been studied by a combined fluorescence-cytochemical, immunocytochemical and ultrastructural approach. The results show that, during development, several ultrastructurally distinct cell types exhibit COOH-terminal gastrin and cholecystokinin immunoreactivity. Furthermore, some cells simultaneously contain both gastrin- and cholecystokinin-specific antigenic determinants. Studies on the time course of development of gastrin and cholecystokinin cells, together with the above-mentioned data, suggest that gastrin cells may be converted into cholecystokinin cells in development. During this period, gastrin, cholecystokinin and secretin cells store the biogenic monoamine, 5-hydroxytryptamine a feature not displayed by the adult counter-parts of these cells. In the adult duodenum, characteristic enterochromaffin (EC) cells store 5-hydroxytryptamin for which, evidence for a possible hormonal role has been presented. Taken together, our data indicate that the differentiation of duodenal endocrine cells occurs in distinct steps, each involving a restriction in the biosynthetic repertoire of the cell.     

Proliferative activity of gastric and duodenal endocrine cells in the rat

Summary The replicative activity and migration of gastrin, somatostatin and serotonin cells in rat stomach and doudenum was studied using combined immunocytochemistry and autoradiography after ³H thymidine pulse-labeling. Our results show that a small proportion of gastrin, somatostatin and serotonin immunoreactive cells displays proliferative activity. The overall labeling index ranged from 1.3% for gastric endocrine cells to 3.2% for duodenal endocrine cells.In a pulse chase experiment, labeling indices of immunoreactive cells were estimated at several time intervals after ³H thymidine administration. Significant differences in labeling index were not found. Migration of ³H thymidine labeled endocrine cells towards the luminal surface was not found in the stomach nor in the doudenum.It is concluded that 1) these endocrine cells have replicating activity; 2) the replicative activity of endocrine cells is higher in the duodenum than in the stomach; 3) the various cell types do not show significant differences in replicating activity and 4) endocrine cells did not seem to migrate to the luminal surface of the mucosa along with the other epithelial cells.     

Quantitative histoenzymologic characteristics of the human submandibular salivary glands]

Quantitative activity of oxidative-reductive and hydrolytic enzymes obtained during operation was investigated in different parts of the human submandibular salivary glands. Quantitative estimation of enzymic activity was done by photometry of the negatives prepared on MY-phi-6. Comparative examination of enzymatic activity made it possible to state that according to the peculiarities of metabolic processes, the cells of striated and intralobular secreting ducts are similar to the cells of the secreting terminal parts. A high activity of NADP-diaphorase, G-6-PhDG and acid phosphatase in the epithelium of the secreting ducts, and parallelism, stated between histoenzymatic and morphologic criteria of functional activity proved the participation of these structural-functional units in secret-producing processes. A high activity of NAK-diaphorase, LDG and acid phosphatase in all the parts and in the secreting ducts system, in particular, ensures, besides the processes of protein secret formation, an active transport of natrium and potassium, formation of final saliva and its discharge.     

Endocrine cells of the duodenal glands in various representatives of Primates]

The duodenum of four species of monkeys, belonging to the genera Macaca and Papio, has been investigated. In order to reveal argyrophil and argentaffin Ec-cells, Grimelius and Masson-Hamperl methods have been used, respectively. In all the species studied in the terminal parts and in the ducts of the duodenal glands presence of endocrine cells is noted; their amount, however, is considerably less than in crypts. Open and close types of endocrine cells++ have been revealed in the glands. A part of the endocrine cells population is argentaffin Ec-cells (about 40% in Papio and 80% in Macaca). This demonstrates participation of serotonin they produce in regulation of the duodenal glands functional activity. Dependence between taxonomic position of the species and degree of endocrine cells++ development in the duodenal glands has been followed. In particular, in representatives of Macaca amount of argyrophil and argentaffin in the glands is greater than in Papio. Possible reasons of the differences are discussed. Comparing the results on investigation of the glands in the primates with those previously obtained for representatives of Carnivora, a suggestion is made concerning some general principles in organization of the proper endocrinic apparatus of the mammalian duodenal glands.     

The functional state of thymus cells following microwave exposure of endocrine glands

Following local microwave exposure (460 MHz, 120 mW/cm2) of rabbits using fluorescent probes and chemiluminescent analysis, conformational rearrangements in nuclear and cytoplasmic membranes and in thymus cell chromatin of the animals as well as changes in the intensity of the lipid free radical peroxidation were seen. The character of the changes observed depended both on the localization of the exposure and on the number of exposures.