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Characterization of macrophage-like cells in the external layers of human small and large intestine.

In the external layers of human small and large intestine macrophage-like cells were characterized by immunohistochemical, histochemical and electron-microscopical methods. Using immunohistochemistry and a number of monoclonal antibodies, the presence and distribution of phenotypic subpopulations of macrophages were evaluated. In all locations macrophage-like cells were identified with antibody EBM11, which recognizes CD68 antigen, C3bi which recognizes CD11b, and partly with an antibody which recognizes protein 150,95 (CD11c). Macrophage-like cells in the external muscle layer were HLA-DR-positive (expressing the MHC class-II antigen), in contrast to macrophage-like cells in the subserosa and submucosa. Macrophage-like cells in the external muscle layer were mostly acid phosphatase-negative, and at the electron-microscopic level they were found to have features of macrophages: primary lysosomes, coated vesicles and pits. However, very few secondary lysosomes were present. Birbeck granules were not observed. It is concluded that in the external muscle layer of human small and large intestine numerous macrophages of a special type are present. It is discussed whether this cell type plays a role in gastrointestinal motility and/or has an immunological function.

Acid Phosphatase↗

Nutritional consequences of the Maillard reaction. The absorption of fructose-L-tryptophan in the large intestine of the rat.

The absorption of fructose-L-tryptophan, an early Maillard reaction product formed from tryptophan and glucose, in the large intestine of the rat was examined. The possible involvement of cecal microflora of the rat in the absorption of fructose-L-tryptophan was investigated. Fructose-L-tryptophan was degraded by the cecal microflora (in vitro) after a 12-hour incubation at 37 degrees. Experiments with rat colonic rings and everted sacs indicated that a passive diffusion of this compound occurs in vitro in the colon of the rat. In vivo absorption was determined by introducing fructose-L-[3-14C]tryptophan directly into the cecum. Twenty percent of the total radioactivity injected was recovered in the urine after 24 hours. Fructose-L-tryptophan was detected in the urine, which suggested that this compound was absorbed by the large intestine but excreted without being metabolized. Approximately 1% of the total radioactivity was recovered in the expired air within 24 hours after injection. The small recovery of fructose-L-tryptophan in feces might indicate that this compound was degraded by the action of microorganisms in the large intestine of the rat.

Animals↗

Prenatal and postnatal development of the large intestine in the insectivore Suncus murinus, the laboratory shrew.

Development of the large intestine in the insectivore Suncus murinus (the laboratory shrew) was investigated from day 21 to 30 of gestation and from birth to 20 days of age. Two days before birth, the stratified epithelium in the large intestine changed into a single layer. Although neither villi nor villus-like structures were ever present, fissures, corresponding to openings of the crypts, appeared on the mucosal surface before birth. These increased in number as well as in width and depth, connected with each other, and gave the mucosal surface a ridge-like appearance by 20 days of age. An elevation containing submucosae appeared shortly after birth and formed a large circular fold during the neonatal period. Goblet cells were the predominant epithelial cell type. Individual epithelial cells were mature-looking a few days before birth; goblet cells contained numerous mucous globules and absorptive cells possessed well-developed organelles. However, although goblet cells increased in number and exhibited active mucous-releasing forms after birth, absorptive cells never showed morphologic evidence of active endocytosis, such as apical endocytotic complexes and large supranuclear vacuoles. Each epithelial cell was similar in ultrastructure to that of the adult shortly after birth.

Age Factors↗

Enhanced rectal potassium secretion in chronic renal insufficiency: evidence for large intestinal potassium adaptation in man.

The role of the large intestine in K+ excretion in chronic renal insufficiency was studied with a rectal dialysis technique in 14 normal subjects and eight normokalaemic, normotensive patients with chronic renal insufficiency. At initial intraluminal K+ concentrations of 10, 20, 30 and 45 mmol/l, net K+ secretion in patients with renal insufficiency was significantly greater than in normal subjects by approximately 1.8 mumol h-1 cm-2. The increase in net K+ secretion was more marked in those patients with creatinine clearances of less than 10 ml/min. In contrast, there were no significant differences in net Na+ and water transport, transmucosal potential difference and plasma aldosterone concentrations between the two groups. With an initial intraluminal K+ concentration of 30 mmol/l, the addition of amiloride (final concentration 1 mmol/l) to the rectal lumen decreased net Na+ absorption and transmucosal potential difference in normal subjects by 69% (P less than 0.005) and 31% (P less than 0.005) respectively, and in patients with renal insufficiency by 75% (P less than 0.05) and 36% (P less than 0.05) respectively, but there was no change in net K+ secretion in either group. These results indicate that the K+ secretory capacity of the rectal mucosa increases in chronic renal insufficiency, and the large intestine may therefore contribute to the maintenance of K+ homoeostasis as renal K+ excretion declines. Increased rectal K+ secretion in renal insufficiency occurs independently of changes in plasma K+ and aldosterone concentrations, net Na+ absorption and transmucosal potential difference, and may reflect stimulation of an active K+ secretory process.

Adult↗

Ultrastructural study of the uptake of ferritin by M cells in the follicle-associated epithelium in the small and large intestines of pigs.

Uptake of ferritin by M cells in follicle-associated epithelium at various sites in the small and large intestines was examined in 4 healthy 5-week-old pigs by use of electron microscopy. A 2.5% solution of ferritin in saline was injected into ligated loops of the jejunum and ileum containing aggregations of lymphoid follicles (Peyer's patches), as well as into intestinal loops containing lymphoglandular complexes at the ileocecal junction, in the central colonic flexure, and in the rectum. As negative control, saline solution was injected into loops at identical localizations. After an exposure period of 2 hours, uptake of ferritin by M cells, but not by enteroabsorptive cells of the small and large intestines, was observed. Numbers of M cells with ferritin and total M cells were counted and the percentage was calculated. Total number of M cells was highest in lymphoglandular complexes in the rectum and lowest on domes of the ileal Peyer's patch. High numbers of M cells with ferritin were found on domes of the jejunal Peyer's patch, and in lymphoglandular complexes at the ileocecal entrance and in the rectum. Only a few M cells on domes of the ileal Peyer's patch and in lymphoglandular complexes in the central colonic flexure contained ferritin. The percentage of M cells with internalized ferritin was similar on domes of the ileal Peyer's patch, and in lymphoglandular complexes at the ileocecal junction and in the rectum. It was higher on domes of the jejunal Peyer's patches and lower in lymphoglandular complexes of the central colonic flexure. Ferritin was found in the apical tubulovesicular system, multivesicular bodies, and a few vacuoles in the central area of M cells. Ferritin was exocytosed into the lateral intercellular spaces next to M cells. Uptake of ferritin by intraepithelial cells in the follicle-associated epithelium could not be documented, but ferritin was present in vesicles of subepithelial macrophages.

Animals↗

Myosarcomas of the small and large intestine: a clinicopathologic study.

A retrospective study was made of 38 myosarcomas of the small and large intestines (34 leiomyosarcomas and 4 malignant leiomyoblastomas). Endoenteric, small, and noninvasive tumors were successfully treated by simple wedge excision, cautery snare removal, or segmental bowel resection with a high 5-yr cure rate of 86% (12/14). Exo-enteric tumors often invaded adjacent structures or perforated into the peritoneal cavity. Extensive resection procedures, including pancreaticoduodenectomy, abdominoperineal resection, and pelvic exenteration salvaged only 13% (2/16) of these patients. Three clinicopathologic factors adversely affected prognosis: i) tumor size greater than 5 cm in diameter, ii) extra-intestinal invasion or free perforation, and iii) high histopathologic grade of malignancy. The presence of none, one, two, or three of these adverse factors gave decreasing 5-yr survival rates of 100, 44, 31, and 0%, respectively. These observations suggest use of a multimodal treatment program that may minimize treatment failure from local as well as distant disease.

Adolescent↗

Surgical management of radiation injury of the small and large intestine.

The following principles should be observed during operations for radiation injuries of the small and large intestine: 1) The objective of operation is modest: to relieve symptoms. 2) Only healthy bowel, which was outside the radiation field, should be anastomosed. 3) Isolated small intestinal injuries should be resected or bypassed, and extensive dissection should be avoided. 4) Colorectal injuries should be treated by diverting descending colostomy, with or without resection of the diseased bowel.

Adult↗

[Distribution of a cell with intracytoplasmic crystal and crystaloid material in the small and large intestine of the rat and mouse].

In suckling and adult rats, distribution in the small and large intestine of crystal-like containing cell was studied and was compared with that of crystal containing cell in the mouse. In the former, cell predominates in cecum and in the latter in the ileum. Numerical differences were statistical significant. It was postulated that these cells might be different. Up to date, they have been regarded as the same cell by other authors and are known as globular leucocyte.

Animals↗

Ingestion of guar-gum hydrolysate partially restores calcium absorption in the large intestine lowered by suppression of gastric acid secretion in rats.

We examined the effects of feeding guar-gum hydrolysate (GGH), a highly fermentable form of dietary fibre with low viscosity, on Ca absorption in the small and large intestines in rats under conditions in which gastric acid secretion was suppressed by a proton pump inhibitor, omeprazole. We also examined the role of the caecum in influencing these effects. The study was designed in a 2 x 2 x 2 factorial arrangement with two diet (GGH-containing (50 g/kg diet) and GGH-free diets) groups, two injection (omeprazole and vehicle) groups and two operation (sham and caecectomy) groups. Apparent Ca absorption was lower in rats administered omeprazole (30 mg/kg body weight per d) for 8 d than in rats administered the vehicle. Ingestion of GGH led to partial restoration of Ca absorption decreased by omeprazole treatment. However, this increment in Ca absorption was not sufficient to meet requirements because the dietary Ca level (3.0 g/kg diet) was the minimum requirement for the intact rats. The small increment in Ca absorption caused by the GGH diet was completely abolished by caecectomy. Soluble Ca pools in the caecal and colonic contents were increased by feeding GGH, and the soluble Ca concentrations were much higher than the Kt values of the Ca active transport system in the large intestine or the serum Ca concentration. These findings suggest that Ca solubilization is not a limiting factor for Ca absorption in the large intestine. Apparent Mg absorption was clearly lower in caecectomized rats than in sham-operated rats, and higher in the GGH-fed groups than in the groups fed on the GGH-free diet, even in the case of caecectomized rats. We conclude that Ca absorption lowered by inhibition of gastric acid secretion is partially restored in rats fed with GGH, but the increment is not sufficient to meet requirements.

Animals↗

Neither motility nor chemotaxis plays a role in the ability of Escherichia coli F-18 to colonize the streptomycin-treated mouse large intestine.

Escherichia coli F-18, isolated from the feces of a healthy human in 1977, is an excellent colonizer of the streptomycin-treated mouse large intestine and displays normal motility and chemotaxis ability. A chemotaxis-defective derivative of E. coli F-18, E, coli F-18 CheA-, and a nonflagellated derivative, E. coli F-18 Fla-, were constructed. These strains were found to colonize the streptomycin-treated mouse large intestine as well as E. coli F-18 when mice were fed both E. coli F-18 and either the CheA- or Fla- derivative at high levels (10(10) CFU of each strain per mouse) or low levels (10(4) CFU of each strain per mouse). Furthermore, E. coli F-18 lost motility and chemotaxis ability when grown in colonic or cecal mucus in vitro despite retaining the ability to synthesize flagella. Thus, it appears that neither motility nor chemotaxis plays a role in the ability of E. coli F-18 to colonize because this strain becomes functionally nonmotile upon growth in the streptomycin-treated mouse large intestine.

Animals↗

Acceleration of large intestine transit time in rats by sennosides and related compounds.

Sennosides A + B and their natural metabolites, sennidins A + B, rheinanthrone and rhein, as well as the synthetic laxative danthron, were investigated for their influence on small and large intestine transit time in rats. Carmine red, as a marker, was administered through a gastric tube for small intestine transit or intracaecally by a chronically implanted catheter for colon transit. High doses of sennosides (250-500 mg kg-1) given orally from 20 min or up to 6 h before marker administration had no effect on small intestine transit time. The metabolites and danthron (10-100 mg kg-1 p.o.) also did not accelerate upper gastrointestinal passage. Intracaecal administration at the same time as carmine red, however, reduced the time for the appearance of the first coloured faeces from more than 8 h in the controls to 46 +/- 9 min after sennosides, 34 +/- 11 min after sennidins, 53 +/- 83 min after rhein and 16 +/- 4 min after rheinanthrone (50 mg kg-1 of each). Danthron was ineffective. Thus, sennosides and their natural metabolites specifically influence large intestinal motility. Acceleration of colonic transport seems to be a major component of the laxative action whereas for danthron motility changes are not responsible for its laxative action. Indomethacin partly inhibited the acceleration of large intestine transit induced by sennosides. An involvement of endogenous prostaglandins may therefore be possible, although a local bolus administration of PGF2 alpha or PGE2 into the caecal lumen neither influenced transit time nor induced diarrhoea.

Animals↗

Dietary fructooligosaccharides change the concentration of calbindin-D9k differently in the mucosa of the small and large intestine of rats.

Previously, we confirmed that dietary fructooligosaccharides (FOS) increase calcium absorption in rats. In this study, we examined the influence of FOS feeding on the concentration of calbindin-D9k of several intestinal segments in rats. Rats in the control group were fed a diet without FOS. Rats in the other two groups were fed the diet containing FOS at either 50 or 100 g/kg for 10 d and subjected to a calcium absorption study. On the final day of feeding, the rats were killed and the entire intestine was removed. The intestinal mucosa was collected from four segments, i.e., the proximal and distal segments of the small intestine, the cecum and the colorectum, respectively. The apparent absorption of calcium increased dose dependently (r = 0.9256, P < 0.0001). Significant positive correlations between apparent calcium absorption and the relative amounts of calbindin in both large intestinal segments were observed (cecum, r = 0.8956, P = 0.0011; colorectum, r = 0.8828, P = 0.0016). Also, significant negative correlations between apparent calcium absorption and the relative amounts of calbindin-D9k in both small intestinal segments were observed (proximal, r = -0.7149, P = 0. 0304; distal, r = -0.8740, P = 0.0021). In conclusion, FOS feeding increases levels of calbindin-D9k in the large intestine, but decreases those in the small intestine. Moreover, these results suggest that part of the stimulatory effect of fructooligosaccharides relates to the transcellular route of calcium absorption in the large intestine of rats.

Absorption↗