Analysis of cell populations in the normal rhesus macaque (Macaca mulatta) lower intestinal tract and diagnostic thresholds for chronic enterocolitis

Rhesus macaques (Macaca mulatta) are used extensively in biomedical research, often with a focus on the gastrointestinal tract, and yet a full characterization of their normal resident intestinal cell populations has not been published. In addition, chronic enterocolitis (CE), also known as idiopathic chronic diarrhea, affects up to 25% of colony-housed rhesus macaques, often requiring euthanasia for welfare concerns and severely limiting their value as a breeding animal or research subject. We aimed to characterize subjective and objective variables in sections of the ileum, cecum, colon, and rectum in 16 healthy rhesus macaques and compare these results with a cohort of 37 animals euthanized for CE to produce relevant diagnostic thresholds and to improve case definitions for future studies. We found neutrophils to be an infrequent but expected component of the large intestinal leukocyte population. Animals with CE had significantly increased total leukocyte populations between crypts in the cecum, colon, and rectum; variable increases in specific cell populations across all levels of the distal intestinal tract; and significantly increased intraepithelial CD3+ T cells in the colon and rectum. Concentrations of enteroendocrine cells, enterochromaffin cells, and intestinal mast cells were not significantly different between healthy and affected individuals. This study characterizes individual leukocyte populations in the rhesus macaque lower intestinal tract, is the first to evaluate rhesus macaque intestinal mast cells, and provides key diagnostic thresholds for evaluating animals with potential CE.

Microbial RNAs Pressure Piezo1 to Respond

Serotonin production by enterochromaffin cells (ECs) is microbiota-dependent, but the mechanism of this is unknown. In this issue of Cell, Sugisawa et al. demonstrate that Piezo1 in ECs senses single-strand RNA (ssRNA) from intestinal microbiota to promote serotonin production. Deletion of Piezo1 in intestinal epithelium promotes bone formation, decreases peristalsis, and protects from colitis because of decreased serotonin.

Immunohistochemical detection of the vomiting-inducing monoamine neurotransmitter serotonin and enterochromaffin cells in the intestines of conventional or gnotobiotic (Gn) pigs infected with porcine epidemic diarrhea virus (PEDV) and serum cytokine responses of Gn pigs to acute PEDV infection

Serotonin is a critical monoamine neurotransmitter molecule stored and released from enterochromaffin (EC) cells into the gut submucosa, transmitting the vomiting signal to the brain. We studied one mechanism by which vomiting is induced in pigs infected with porcine epidemic diarrhea virus (PEDV) by characterization of swine EC cells by immunohistochemistry. Conventional or gnotobiotic (Gn) 9-day-old pigs [PEDV-inoculated (n = 12); Mock (n = 14)] were inoculated orally (8.9-9.2 log₁₀ genomic equivalents/pig) with PEDV PC21A strain or mock. This is the first identification of serotonin-positive EC cells in swine by immunohistochemistry and mainly in intestinal crypts, regardless of infection status. They were morphologically triangular-shaped or round cells with or without apical cytoplasmic extensions, respectively. At post-inoculation hour (PIH) 16 or 24, when vomiting was first or frequently observed, respectively, PEDV infection resulted in significantly reduced numbers of serotonin-positive EC cells in duodenum, mid-jejunum, ileum, or colon. However, two of three PEDV-inoculated Gn pigs that did not yet show vomiting at PIH 16 had numbers of serotonin-positive EC cells in duodenum, ileum and colon similar to those in the negative controls. These findings suggest that serotonin release from EC cells (increased serotonin levels) into the gut submucosa might occur early PEDV post-infection to stimulate the vagal afferent neurons, followed by vomiting. Serotonin might be involved in the mechanisms related to vomiting in PEDV-infected piglets. We also found that mid-jejunum was the primary site of acute PEDV infection, and that systemic innate and pro-inflammatory cytokine responses were induced during the acute stage of PEDV infection.

ON THE EXPERIMENTAL DISCHARGE OF THE GASTRIC AND INTESTINAL ARGENTAFFIN CELLS

Reserpine discharges the azo positive reducing substance from both gastric and intestinal basal granular cells in the guinea pig. Regeneration was slower than in previous reports and apparently more rapid in the duodenum than in the stomach or ileum.

The numbers of cells demonstrated in the normal duodenum and ileum respectively, as well as in the duodenum and ileum of the 7 day post reserpine animal, do not correspond particularly closely with the 5-hydroxytryptamine assays.

Physostigmine and ephedrine failed to discharge the reactive material from basal granular cells of the guinea pig stomach and intestine.

Argyrophil cells persist throughout the reserpine discharge period, during which argentaffin, azo positive basal granular cells are not demonstrable.

Nikolai Konstantinovich Kulchitsky (1856-1925)

Nikolai Kulchitsky is best remembered for his identification of the Kulchitsky (enterochromaffin) cell. His life spanned a teaching and scientific career at Kharkov University, employment as the Imperial Minister of Education for all Russia, work in a soap factory and flight from the Russian Revolution to London, and a position at the University College with Elliot Smith. His subsequent contributions to the anatomic delineation of dual nerve-endings in the muscle were highly regarded, although his identification of the enterochromaffin cell (1897) remains his enduring scientific legacy. The observation of a cardinal neuroendocrine cell of the gut formed the basis for the subsequent delineation of the diffuse neuroendocrine system and provided the cellular framework on which the discipline of gut neuroendocrinology would be established. Kulchitsky's mysterious demise in a bizarre lift-shaft accident at UCL on his 69th birthday tragically terminated a life of service to science.

From Leningrad to London: the saga of Kulchitsky and the legacy of the enterochromaffin cell

By the end of the 19th century, the subject of internal secretion and the consequences of its perturbations had been explored in considerable depth but with little clear understanding. Despite the anatomic delineation of the majority of the glands and tissues that comprised the gross endocrine system, the cellular basis and the interactions between the 'internal glands' and the nervous system had not been clearly delineated. Prominent early investigators in the field included Rudolf Peter Heidenhain (1834-1897), who described a novel class of clear cells (1868), Paul Langerhans (1847-1888), who identified pancreatic islets in 1869, and M.C. Ciacco (1877-1956), who coined the term 'enterochromaffin' (1906). Their contributions facilitated the description of the diffuse neuroendocrine system (DNES) by F. Feyrter (1938) which allowed for the understanding of a syncytial regulatory system that consisted of both endocrine and neural components. This rich developmental history often reveals the name of Kulchitsky, but little recognition has been given to his seminal contributions. Indeed the Russian, Nikolai Konstantinovich Kulchitsky (1856-1925), both due to his modest and unassuming nature and the tragic events of his life, was little recognized and has been relegated to a mere eponymous attribution. In reality, his life bears legacy to rich scientific contributions spanning a great teaching and scientific career at Kharkov University, to responsibilities as the Imperial Minister of Education for all of Russia. He identified the Kulchitsky cell, trained and mentored numerous professors of histopathology, was incarcerated by the Bolsheviks and worked in a soap factory to save his life. He and his family finally fled on a British battleship with the remnants of the Russian Royal family to England where he secured a position with Bayliss and Starling at University College, London (UCL). His mysterious demise in a lift-shaft accident on his 69th birthday tragically terminated a life of great service to science and teaching. He excelled as a histopathologist and was responsible for the early description of tonsillar and gut epithelial leucocytes as well as defining components of the Ascaris life cycle. At UCL, his contributions to the anatomic delineation of muscle nerve endings were highly regarded and widely admired. It is, however, his identification of the enterochromaffin cell in 1897 for which he is most remembered since this observation formed the basis for the subsequent delineation of the DNES and provided the cellular framework on which the discipline of gut neuroendocrinology would be established.

[Study of nucleolar organizer regions in chromosomes of bladder cancer]

The data on tumor at presentation and 5-year follow-up after surgery for urinary bladder cancer were assessed retrospectively in 62 patients, with particular emphasis on nucleolar distribution revealed by silver staining. A close relationship was found between mean values and even distribution of argentaffine granules and nucleoli in tumor cells, on the one hand, and morphological features of carcinoma and clinical course, on the other. Also, correlations were established between distribution of nucleoli, nucleolar organizer regions and histological pattern (p=0.001), stage (p=0.013), grade (p=0.001), multiplicity (p=0.001), size (p<0.001), localization (p=0.005), frequency (p=0.014), period (p<0.001) and 5-year relapse-free survival (p=0.021). Grade and stage of disease appeared to be pivotal to tumor progression. Favorable course was reported when mean values of number of nucleoli and standard error of argentaffine granule distribution in tumor cells were less than 1.65 and 4.4. respectively. Relapse-free time was the shortest when coefficient of variation of distribution of argentaffine granules and nucleoli in tumor cells exceeded 42%.

Studies on the relationship of 5-hydroxytryptamine and the enterochromaffin cell to anaphylactic shock in mice

Protection against anaphylactic shock in mice by reserpine has been shown to be a delayed phenomenon, probably not dependent upon a direct effect of reserpine. The release and depletion of catechol amines by reserpine show little likelihood of being responsible for protection because these substances are in themselves protective against anaphylactic shock, while β-TM 10, a drug which interferes with their release is not. Since L-α-methyl dopa and reserpine both deplete serotonin, and since both protect against anaphylactic shock, it is proposed that serotonin depletion is responsible for the protection. Enterochromaffin substance is depleted in anaphylactic shock. It is also depleted by reserpine and serotonin, both of which protect against anaphylactic shock when given prior to challenge with antigen. The amount of enterochromaffin substance seems to correlate with susceptibility to anaphylactic shock. The behavior of animals undergoing anaphylactic shock and the effect of shock on body temperature is similar to the effects on behavior and temperature of treatment with reserpine, which is known to release serotonin. The effect of monoamine oxidase inhibition on animals undergoing anaphylactic shock is also similar to the effect of monoamine oxidase inhibition on animals given reserpine. These results are consistent with the views that the release of serotonin is causally related to anaphylactic shock in mice and that serotonin is accumulated in the chromogenic material of the enterochromaffin cell.

Expression of the chromogranin A-derived peptides pancreastatin and WE14 in rat stomach ECL cells

The ECL cells constitute the predominant endocrine cell population in the mucosa of the acid-secreting part of the stomach (fundus). They are rich in chromogranin A (CGA), histamine and histidine decarboxylase (HDC). They secrete CGA-derived peptides and histamine in response to gastrin. The objective of this investigation was to examine the expression of pancreastatin (rat CGA266-314) and WE14 (rat CGA343-356) in rat stomach ECL cells. The distribution and cellular localisation of pancreastatin- and WE14-like immunoreactivities (LI) were analysed by radioimmunoassay and immunohistochemistry with antibodies against pancreastatin, WE14 and HDC. The effect of food deprivation on circulating pancreastatin-LI was examined in intact rats and after gastrectomy or fundectomy. Rats received gastrin-17 (5 nmol/kg/h) by continuous intravenous infusion or omeprazole (400 micromol/kg) once daily by the oral route, to induce hypergastrinemia. CGA-derived peptides in the ECL cells were characterised by gel permeation chromatography. The expression of CGA mRNA was examined by Northern blot analysis. Among all of the endocrine cells in the body, the ECL cell population was the richest in pancreastatin-LI, containing 20-25% of the total body content. Food deprivation and/or surgical removal of the ECL cells lowered the level of pancreastatin-LI in serum by about 80%. Activation of the ECL cells by gastrin infusion or omeprazole treatment raised the serum level of pancreastatin-LI, lowered the concentrations of pancreastatin- and WE14-LI in the ECL cells and increased the CGA mRNA concentration. Chromatographic analysis of the various CGA immunoreactive components in the ECL cells of normal and hypergastrinemic rats suggested that these cells respond to gastrin with a preferential release of the low-molecular-mass forms.

Argyrophil cells, mast cells, and histamine in the fundic mucosa of antrectomized patients

Fasting gastrinemia, fundic argyrophil cell density, mast cell number, basal fundic histamine content and histidine decarboxylase activity were determined in 20 antrectomized patients and 20 control subjects. Fasting gastrinemia and fundic argyrophil cell density were significantly lower in antrectomized patients than in controls, whereas fundic mast cell number, basal histamine content, and histidine decarboxylase activity did not differ significantly between the two groups. In antrectomized patients the basal fundic histamine content appears related to the fundic mast cell number, as a consequence of the reduced effect of gastrin on argyrophil cells.

The effect of omeprazole-induced hypergastrinemia on the oxyntic mucosa of mastomys

Mastomys is a rodent with a high incidence of spontaneous carcinoids in the acid-producing part of the stomach. The present study was conducted to examine whether hypergastrinemia could promote tumor formation in this species. Mastomys, 4 months of age, were treated for 5 months with omeprazole subcutaneously, 100 mumol/kg body weight daily, and compared with mastomys given the vehicle only. The plasma gastrin concentration and the number of antral gastrin cells were increased in the omeprazole-treated group. The hypergastrinemia was associated with elevated histidine decarboxylase activity and histamine content in the oxyntic mucosa and with a trophic effect on the oxyntic mucosa and the enterochromaffin-like cells. However, no carcinoid tumors were observed, possibly because the strain of mastomys studied does not produce carcinoids spontaneously.

Hymenolepis diminuta: changes in intestinal morphology and the enterochromaffin cell population associated with infection in male C57 mice

Mean villus height, crypt depth and the number of 5-HT-positive enterochromaffin (EC) cells have been examined in two regions of the small intestine (20-30% and 60-70% distance from the pylorus) of male, 6 to 8-week-old, C57 mice following a 5-cysticercoid infection of the rat tapeworm, Hymenolepis diminuta. Test mice and sham-infected controls were autopsied 0, 4, 8, 10, 14 and 28 days post-primary infection (p-1 degree-i) and 2, 4, 5, 7 and 14 days post-secondary infection (p-2 degrees-i), administered 28 days p-1 degree-i. Morphometric analysis revealed a statistically significant increase in crypt depth in the 60-70% intestine region in infected mice during both primary and secondary infections; no significant deviation from the control was observed for villus height in infected mice. Statistical analysis showed a significant increase in the number of 5-HT-positive EC cells in infected mice. This response occurred in the lower portion of the intestine on days 10-p-1 degree-i and 5-p-2 degrees-i, and was not due to increased mucosal surface area in this region. Results are discussed with reference to murine cestode rejection and the possible involvement therein of the neuroendocrine system.

Endocrine cell populations in the colon and rectum of cat, dog, and monkey: fine structure, immunocytochemistry, and distribution

Comparative and quantitative ultrastructural studies of endocrine cells from the large bowel of European cat, beagle dog, and the monkey Callitrix jacchus were performed. The cat and monkey exhibited a roughly similar distribution of colonic endocrine cells with a frequency increasing toward the distal. On the contrary, the highest endocrine cell frequency in the dog colon was in the cecum. In the dog and monkey, enterochromaffin (EC) cells were predominant in all segments. In the cat, non-EC cells were predominant in the proximal colon. For each colonic segment, relative percentages of EC and non-EC cells appeared on the whole to be roughly stable between individuals of the same species. Three subtypes of EC cells were distinguished in each species. Non-EC cells were characterized by large variation in size and electron densities of their granules: Mean granule size per cell extended from 210 to 850 nm in cat, 310 to 770 nm in dog, and 130 to 470 nm in monkey. In each species, statistical analyses indicated that the non-EC cell population was composed of two or more subpopulations. Some similarities were found between colonic endocrine cells of the monkey and man, whereas obvious differences appeared between the two carnivorous mammals. Immunocytochemical studies demonstrated the presence of cells containing enteroglucagon, somatostatin, or a pancreatic polypeptidelike substance in the colon of the monkey and the rectum of the three mammals. Correlative immunocytochemical and ultrastructural studies showed that the three kinds of immunostained endocrine non-EC cells in each species had rather round granules, with great electron densities. Some subpopulations, morphologically distinguished, did not react to any of the antisera used. This suggests either the existence of secretory cycle in some endocrine cells or, perhaps, the presence of peptides still unknown in this part of the gut.

The vagus exerts trophic control of the stomach in the rat

Bilateral subdiaphragmatic truncal vagotomy results in great functional changes in the stomach although the changes in the gastric mucosal architecture are small. A trophic effect of the vagus on the stomach is revealed after unilateral vagal sectioning, taking advantage of the fact that, in the rat, each vagal trunk innervates only one side of the stomach, and that denervation of one side does not impair the functional capacity of the other. The denervated side of the stomach displayed atrophy that was reflected in reduced weight and height of the oxyntic mucosa and a reduced density of argyrophil cells. The lack of atrophy after bilateral vagotomy can be explained by counteracting forces, in that the subsequent rise in gastrin secretion (due to lack of acid feedback inhibition of gastrin release) probably masks antitrophic effects of the vagotomy per se. Interestingly, the number of somatostatin cells in the oxyntic mucosa was not reduced after unilateral vagotomy, nor was the weight of the antral mucosa or the density of enterochromaffin and gastrin cells in the antrum on the denervated side.

Innervation of the gall bladder and biliary pathways in the guinea-pig

The innervation of the gall bladder and the biliary pathways was studied in guinea-pigs by means of histochemical methods for catecholamines and for acetylcholinesterase on whole mount preparations, on cryostat sections and on sections of plastic-embedded tissues. The gall bladder contains on average 367 neurons in a ganglionated plexus which lies at the outer surface of the muscle coat. The overall appearance of this plexus is rather similar to that of the submucosal plexus of the duodenum. From the gall bladder the plexus extends into the cystic duct, the hepatic duct and the common bile duct, but from the middle portion of the common bile duct downwards, it is positioned at or near the inner surface of the muscle coat. Concurrently with the marked increase in muscle thickness in the lower parts of the common bile duct, another ganglionated plexus appears, which is truly intramuscular. The latter plexus is highly developed, lies usually between longitudinal and circular muscle and resembles in appearance the myenteric plexus of the duodenum, with which it is in continuity. Throughout the biliary system, the extent of the ganglionated plexus is roughly related to the extent of the musculature. An exchange of adrenergic fibres between the ganglionated plexus and perivascular nerves is observed in the gall bladder. Another nerve plexus, without ganglia but rich in adrenergic and acetylcholinesterase-positive fibres, lies between the mucosa and the muscle coat. Very few nerve fibres run into the musculature of the gall bladder. On the other hand, in the thick musculature of the lower portion of the common bile duct, several intramuscular nerve fibres are found.

Diffuse enterochromaffin-like (ECL) cell hyperplasia and multiple gastric carcinoids: a complication of pernicious anaemia

A man with long-standing pernicious anaemia developed multiple gastric carcinoid tumours with a background of diffuse enterochromaffin-like cell hyperplasia. There is evidence that enterochromaffin-like cells synthesis and store histamine and that their proliferation is stimulated by high serum gastrin levels. Gastric carcinoid tumours can be difficult to differentiate from the more common adenocarcinomas and may be a more frequent complication of pernicious anaemia than is currently recognised.

G-cell populations in resected stomachs from gastric and duodenal ulcer patients

The G-cell population in the pyloric antrum and proximal duodenum was studied quantitatively by immunofluorescence in specimens from 10 gastric and 12 duodenal ulcer patients. In both groups, G-cell density was highest in the pyloric antrum and much lower in the intermediate zone and proximal duodenum, and G-cell counts were statistically higher at the greater than the lesser curvature. The estimated total number of G cells in the whole pyloric antrum including the intermediate zone in the duodenal ulcer group was (1.806 +/- 0.347) x 10(7), this value was significantly greater (P less than 0.05) than that of (0.872 +/- 0.207) x 10(7) in the gastric ulcer group. This difference was due to a higher incidence of intestinal metaplasia and a decrease in the thickness of the antral mucosa in the latter group. The estimated total number of G cells showed a significant negative correlation not only with the patient age (P less than 0.01) but also with the degree of intestinal metaplasia of the antral mucosa (P less than 0.01) in both duodenal and gastric ulcer patients.

Alterations in serum and antral gastrin levels in genetically diabetic mice

Many gastrointestinal structural and functional properties are known to be altered in diabetes. In this study, we investigated whether serum and tissue gastrin levels are abnormally altered in a strain of genetically diabetic mice (C57BL/KSJ). Both serum and antral gastrin concentration were found to be significantly increased 3.4- and 2-fold above normal values in diabetic mice fed ad libitum. The increase in tissue gastrin concentration is most probably due to an increase in both cellular gastrin content and G-cell number, since the latter property is increased 130% in diabetic animals. Pair feeding studies demonstrated that diabetes associated hyperphagia is not a major factor in inducing these endocrine changes, since antral and serum gastrin are still significantly elevated above normal in diabetic animals fed a restricted diet. G-cell number, however, is not significantly increased above normal values in pair fed diabetic mice. The peak serum gastrin concentration after a meal and the duration of postprandial hypergastrinemia are also significantly increased above normal in diabetic animals. Gel filtration chromatography studies indicate that the antral nucosae of normal and diabetic mice have identical molecular forms of the hormone. It is therefore concluded that antral and serum gastrin concentration are increased in genetically diabetic mice due to both dietary alterations and other, as yet undefined, factors specific for the disease, and that the resultant hypergastrinemia may contribute to some of the gastrointestinal alterations seen in diabetes.

Carcinoid tumor in retinitis pigmentosa

A carcinoid tumor was discovered by chance in a 25-year-old woman with the dominant type of retinitis pigmentosa. Although a coincidental association cannot be ruled out, there is at least a possibility that the two diseases have a common embryologic origin.

The enteroendocrine cells during the normal development of the rat and in some human digestive diseases

The enteroendocrine cells were studied in rats from one day to two years of age. A gradual increase in the number of argentaffin granules and cell volumes paralleling the ageing was observed. The volumes of argentaffin cells in rats reached a maximum at 9 months and decreased towards two years. The argentaffin cells of the intestine are significantly larger than the gastric ones. No significant correlation was found between argentaffin granules number and cell volumes and the gastric or duodenal ulcers. A slight hyperplasia of enteroendocrine cells around the gastric ulcers was noticed.

The release of serotonin from rat duodenal enterochromaffin cells by adrenoceptor agonists studied in vitro

The serotonin (5-HT) content of enterochromaffin cells (EC) was studied by a cytofluorimetric method in biopsies from rat duodenal mucosa after in vitro incubation with different adrenoceptor agonists and antagonists and acetylcholine (ACh). Noradrenaline (NA), Adrenaline (A) and Isoprenaline (IP) caused a decrease of 5-HT in EC down to 40--60% and for NA and A this effect was concentration-dependent. The effect was antagonized by d,1-propranolol but not by d-propranolol, metoprolol, phentolamine or phenoxybenzamine indicating that the 5-HT release from EC is probably mediated via a true beta-adrenoceptor mechanism possibly of the beta2 type. ACh also decreased the 5-HT content of EC but was much less potent than the adrenergic substances. Dopamine (DA) had no effect.

Epithelial mucosubstances and argyrophil cells in Brenner tumours

Brenner tumours of various degree of malignancy were investigated by histochemical methods. The cells lining the cystic cavities in the benign Brenner tumours contained various amounts of PAS-positive, diastase resistant secretory material mixed with small amounts of sulpho- and carboxymucin. The borderline and malignant tumours contained more acidic mucins than the benign tumours. All tumours contained glycogen. Argyrophil and argentaffin cells have not earlier been detected in the Brenner tumours but in this study they were detected in twelve of the 18 Brenner tumours. These cells were not proliferating and therefore Brenner tumour should not be included in the group of APUDomas.

[Interrelationship between the enterochromaffin and several connective tissue cells in the wall of the small intestine following sensitization with an organotropic antigen]

The problem of main cell elements in the intestinal mucosa and their interrelations at different terms of sensibilization (7, 14, 21, days), anaphylactic shock and during post-shock period (3, 7, 14, 21 days) are considered in the work. Some data on quantitative interrelations of enterchromaffine cells, macrophages, labrocytes and plasma cells in the control animals are presented. The amount macrophages under the organotropic sensibilization and during post-shock period increases, their functional activity is growing; the quantity of enterochromaffine cells correlates with that of labrocytes; the amount of plasma cells increases under sensibilization and decreases during the post-shock period.

Enterochromaffin cells in the duodenal mucosa of children with coeliac disease

A cell counting technique was used to count enterochromaffin (EC) cells in the duodenal mucosa of 10 children with coeliac disease and 10 controls, and significantly greater numbers of EC cells were found in children with coeliac disease. In four children with a clinical history suggestive of coeliac disease, but with minor histopathological changes in the duodenum, gluten challenge resulted in increased numbers of EC cells. Abnormalities of 5-hydroxytryptamine metabolism in coeliac disease may result from hyperplasia of EC cells in the small intestine.

On the ultrastructure of polypeptide hormone-producing cells in the gut of the ascidian, Ciona intestinalis L. and the bivalve, Mytilus edulis L

Ultrastructural evidence has been found for the presence of polypeptide hormone-producing cells in the gut of Ciona intestinalis L. and Mytilus edulis L. which do not appear to have been described before. Due to their localization and ultrastructural characteristics, it is suggested that the cells in Mytilus edulis probably produce an insulin-like substance and that some of these cells in Ciona interstinalis may produce 5-HT (5-Hydroxytryptamine). In each species only one granulated cell type can be observed; The granules, which are electron dense and membrane bound, also show a halo. The average diameter of the granules is 100-200 nm for Ciona and 200-400 nm for Mytilus.

Rectal mucosal adrenergic innervation and enterochromaffin cells in ulcerative colitis and irritable colon

Rectal mucosal biopsies of 13 patients suffering from ulcerative colitis, 7 patients presenting symptomatology typical of irritable colon, and 7 control persons were studied by the recently introduced glyoxylic-acid-induced fluorescence histochemical method. In ulcerative colitis, compared to control specimens: 1) the density of the adrenergic nerve network was significantly pronounced; 2) the mean diameter of the varicosities and the proportional share of large varicosities were increased, as well as the number of varicosities per a given length of an axon; 3) the intensity of the fluorescence of varicosities of comparable size was significantly increased; 4) the number of enterochromaffin cells was significantly decreased. In irritable colon, compared to control specimens, the number of enterochromaffin cells was significantly increased. These findings suggest that biogenic amines are somehow involved in both ulcerative colitis and irritable colon. The fluorescence histochemical method used was found sensitive, specific, and suitable for comparative studies on human clinical material.

Pancreatic APUD cells in older chick embryos, with special reference to their identity

Pancreatic APUD cells showing formaldehyde-induced fluorescence in Black Australorp chick embryos of nine to eighteen days of incubation, proved, on subsequent staining and silver impregnation, to be A, B, D and, from sixteen days, enterochromaffin (EC) cells. EC and D cells were scattered in the exocrine parenchyma, the latter cells increasing with time. Some group of B cells were associated with large A islets from the ninth day of incubation onwards. The composition of A islets (A and some D cells) and B islets (B and some D cells) and the distribution attained (A islets in the splenic and third lobes; B islets in all lobes), accords with the situation reported for adults.

A carcinoid occurring in the testis

Carcinoids of the testis are rare tumours developing in three different ways: 1. It may differentiate within a teratoma, 2. it may be a metastasis of a "loco alieno" seated carcubiud abd 3. it may represent a real primary carcinoid. The observation of a primary testicular carcinoid in a man aged 55 years afforded the opportunity to study such a tumor for the first time by electron microscopic and fluorescence microscopic methods. Thereby, it could bw shown, that this testicular carcinoid corresponds to the carcinoids of the lower small gut. According to the specific ultrastructure of the intracytoplasmic granules it must derive histogenetically from an EC-cell. At the moment it cannot be decided whether the primary testicular carcinoid represents an autochthonous tumor of the male gonad or solely a teratoma with one-sided differentiation in the sense of a simplified teratoma.

Separation of gastric mucosal cells of rat with proteolytic enzymes, pronase and trypsin, with special reference to the collection, morphology and viability of the generative cells

Methods to separate and collect gastric mucosal cells of the rat using proteolytic enzymes were devised. Pronase (1.0%) achieved better results than did trypsin (2.0%) in collecting single isolated cells with higher cell yields and viability. The cells dissociated with trypsin retained glandular structures as in situ. The measurement of radioactivity revealed that the incorporation of 3H-thymidine into generative cells was highest in the cell suspension collected by the second 15 min dissociation. It was concluded that the most effective method to obtain dissociated cells from the generative zone of the mucosa is to collect the cells dissociated with 1.0% pronase continuously for a period from 15 to 45 min after the start of dissociation. On autogradiographic analysis with 3H-thymidine, the ratio of generative cells was 10%, approximately 3 X 10(5) cells, in the specimens.

Identification of the intestinal cell storing gastric inhibitory peptide

Small intestinal mucosal samples from man, pig and dog, were subjected to sequential or correlative silver impregnation techniques, applied to immunocytochemical preparations and at the ultrastructural level. The cell reacting with anti-GIP sera was identified as the ultrastructurally classified K cell and we propose that the term GIP cell be used in place of the latter. This cell can thus be recognized by its strong reactivity with the Sevier-Munger staining procedure, provided that the equally strongly reacting EC cell is excluded by virtue of its argentaffinity with the Masson technique.

Cellular localization of a vasoactive intestinal peptide in the mammalian and avian gastrointestinal tract

Immunohistochemical studies using an antiserum to a pure porcine vasoactive intestinal peptide, possessing no cross reactivity against the related hormones glucagon, secretin, and gastrin-inhibitory peptide, revealed a wide distribution of vasoactive intestinal peptide cells throughout the entire length of the mammalian and avian gut. The highest numbers of cells were present in the small intestine and more particularly in the large intestine in all species investigated. Three types of endocrine cell in the mammalian gut are sufficiently widely distributed to be considered as the sites for production of vasoactive intestinal peptide. In the avian gut there are only two identifiable cell types. Sequential immunofluorescence and silver staining showed, in the bird, that the enterochromaffin (EC) cell was not responsible. This procedure could not be used in our mammalian gut samples but here serial section immunofluorescence for enteroglucagon and vasoactive intestinal peptide indicated that the two cells were not identical and that each was differently localized in the mucosa. These results leave the D cell of the Wiesbaden classification as the most likely site for the production of vasoactive intestinal peptide. The final identification must come from successful immune electron cytochemistry but this has not yet been achieved.

ON ARGYROPHILE AND ARGENTAFFIN REACTIONS IN INDIVIDUAL GRANULES OF ENTEROCHROMAFFIN CELLS OF THE HUMAN GASTRO-INTESTINAL TRACT

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