Selective migration of lymphocytes within the mouse small intestine

The factors which determine the migration of lymphoid cells to lamina propria or Peyer's patches of mouse small intestine have been investigated by autoradiographic tracing of intravenously injected spleen, thymus and lymph node cells. The numbers of labelled cells found in antigen-free grafts of foetal small intestine were compared with the numbers in normally sited gut. Thymus, normal spleen and B spleen lymphocytes, labelled with [³H]adenosine or [5-³H]uridine, were confined to Peyer's patches in normal and grafted gut. [³H]Thymidine-labelled lymphoblasts from the mesenteric nodes of young (19–22 days) mice and mice infected with Nippostrongylus brasiliensis were found in the lamina propria of both graft and normal small intestine, but [³H]thymidine-labelled lymphoblasts from oxazolone-primed lymph nodes did not migrate to the villi. The possible roles of intraluminal antigens, source of cells and changes in cell surface receptors during differentiation, in determining the selective migration of cells to the lamina propria and Peyer's patches, are discussed.     

Projections of substance P-containing neurons within the guinea-pig small intestine

The origins of substance P immunoreactive axons in the small intestine of the guinea-pig were investigated with an immunohistochemical technique in whole mount preparations. Nerve pathways were interrupted either in vitro or in vivo to detect the accumulation of substance P proximal to the lesion and the disappearance of immunoreactive fibres resulting from the degeneration of the severed axons. Various operations, namely, extrinsic denervation, interruption of the myenteric plexus (myotomy) or removal of the myenteric plexus with the longitudinal muscle (myectomy), were performed prior to examination of substance P-containing neurons.There are several projections of substance P-containing neurons which supply the intestine. Extrinsic neurons are the sources of two projections, one to submucosal blood vessels and one to the submucous ganglia. Intrinsic neurons located in the submucous ganglia supply the villi. Five projections arise from the myenteric plexus, a very short projection ending either within the same row of ganglia or within the adjacent rows of ganglia on both sides, a longer projection within the myenteric plexus, a very short projection to the circular muscle, a projection to the submucous ganglia where the axons surround most of submucous nerve cell bodies, and a projection to the villi.It is likely that the highly organised patterns of innervation by different substance P-containing neurons have specific roles in the intestine. Some of these neurons may act as sensory neurons, others as interneurons, and yet others as motor neurons in nerve pathways within the enteric nervous system.     

Distribution of histamine in the lumen contents of the small intestine of uninfected andHymenolepis diminuta-infected rats

Using a specific radioenzymatic assay, histamine was detected and measured in the lumen contents of six different segments of the small intestine of uninfected rats and rats infected withHymenolepis diminuta as well as in worm tissues. The distribution of histamine in the lumen of the small intestine of uninfected rats was found to range from 1.4±0.1 M in the first (anterior) segment to 0.59±0.13 mM in the sixth (posterior) segment. There were no significant differences between these concentrations and those found in the lumen contents of intestine from rats infected withH. diminuta. On the other hand, although mostH. diminuta was confined to the second and third segments, the concentration of histamine associated with the worm tissues (5.4±0.4 M) was significantly lower than that inHymenolepis-containing intestinal segments. The data suggest that established infections ofH. diminuta do not cause a significant increase in histamine levels in host's intestinal lumen, nor do they affect the spatial gradient in the lumen.     

Absorption of two proline containing peptides by rat small intestine in vivo.

1. Glycyl-L-proline and L-prolyl-glycine are two dipeptides that are poorly hydrolysed by brush border peptide hydrolases in vitro. The present study was undertaken to investigate in vivo intestinal absorption of the two dipeptides in male Wistar rats. A steady-state perfusion technique has been used and jejunal and ileal absorption studied by comparing rates of absorption of constituent amino acids from dipeptide and equivalent equimolar amino acid solutions. 2. Glycine and proline were absorbed at the same or faster rates during perfusion of 10 mM glycyl-L-proline than during perfusion of 10 mM-L-prolyl-glycine than during perfusion of its equivalent equimolar amino acid solution. Conversely, the two constituent amino acids were absorbed at slower rates during perfusion of its equivalent amino acid solution. As expected very low concentrations of free amino acids were detected during the jejunal dipeptide perfusions but higher concentrations were detected during the ileal perfusions. 3. The addition of 40 mM L-prolyl-glycine to the 10 mM glycyl-L-proline solution did not affect the rates of disappearance of glycyl-L-proline. The addition of 40 mM glycyl-L-proline to 10 mM L-prolyl-glycine however had a significant inhibitory effect on the disappearance of L-prolyl-glycine. It is concluded that the two dipeptides may be absorbed by different peptide transport systems.     

Na dependence of monosaccharide absorption in isolated rabbit small intestine,perfused through lumen and vascular bed

Na dependence ofd-glucose and 3-O-methyl-d-glucose absorption was investigated using the isolated rabbit small intestine perfused through the lumen and the vascular bed, thus imitating in vivo conditions.No dependence of monosaccharide transport on luminal Na concentration was demonstrable if the lumen was perfused at low flow rate. Due to Na secretion, however, Na concentration in the lumen bulk phase, initially being zero, was raised to more than 20 mmol/l during the course of the experiments. Na dependence of sugar transport could be shown, however, if (1) Na secretion was decreased (by use of a vascular medium with low Na concentration) or if (2) unstirred layer thickness was reduced (by enhancement of luminal flow rate). Both conditions allowed the Na concentration near the brush border membrane to be controlled. The results provide an experimental explanation for the apparently low degree of Na dependence of monosaccharide absorption under in vivo conditions.     

The transfer of immune complexes from the lumen of the small intestine to the bloodstream in sucking rats.

The epithelial cells along the small intestine of the sucking rat display specific receptors for IgG. These permit the uptake and transcellular transport of IgG, usually presented in milk, from the gut to the bloodstream. Antigen already combined with IgG may also gain access to the bloodstream by this route, but no data exists to show whether this could be sufficient to immunize or to induce tolerance in the young rat to a future exposure to antigen. Monoclonal IgG1 antibody to horseradish peroxidase was used in order to quantitate such a transfer of antigen, using the electron microscope and also studies with radiolabelled antigen and/or antibody. It was found that much less intact antigen was transferred to the bloodstream than would have been calculated from the quantity of antibody transported. Also, IgG1 combined with antigen was more likely to be broken down intracellularly than free IgG1. This was compared with the transport across rat hepatocytes of monoclonal polymeric IgA anti-horseradish peroxidase. The transfer of polymeric IgA from blood to bile was the same whether or not the IgA was complexed with antigen. However, as for the IgG system, less antigen was transported intact into bile than might have been expected theoretically.     

Properties of mechanosensitive neurons within Auerbach's plexus of the small intestine of the cat

Three different kinds of mechanosensitive neurons were detected by direct electrical recording from Auerbach's plexus. Neurons classified as fast-adapting mechanoreceptors discharged spikes at the onset of stimulation, and the discharge stopped during a sustained stimulus of constant intensity. Slowly-adapting mechanoreceptors maintained during sustained stimulation, a steady discharge at a frequency that was a direct function of the intensity of the stimulus. Tonic type neurons responded to mechanical stimulation with a prolonged train of spikes which had a consistent pattern from preparation to preparation. Once the tonic-type cells were triggered, the discharge followed a characteristic time course that was unchanged by further increase or decrease in stimulus intensity. Tonic-type neurons are probably not first order sensory neurons, but they may be activated by input derived from primary mechanoreceptors. Frequency of discharge of slowly-adapting mechanoreceptors was increased by histamine. This appeared to be secondary to histamine-induced contractile activity of the musculature.     

Gaseous equilibrium between blood and the lumen of the intestine

Summary A study was made of the gaseous exchange between the cavity of the small intestine and the blood flowing from it in the mesenteric veins. The gaseous composition of the blood in the mesenteric veins was examined after air or nitrogen introduced into the intestine had reached a constant composition. The oxygen tension in the venous blood was always 15–35 mm Hg higher than that in the intestinal lumen. The oxygen tension in the intestine remained very low despite the abundant blood supply.(Presented by Active Member AMN SSSR V. N. Chernigovskii) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 50, No. 9. pp. 45–48, September, 1960     

Nonspecific resistance to infection expressed within the Peyer''s patches of the small intestine.

Intraperitoneal or intraduodenal pretreatment of mice with dead Corynebacterium parvum failed to produce significant nonspecific resistance to Salmonella enteritidis infection in the Peyer's patches of the small intestine. However, mice pretreated with a single oral infection of live Listeria monocytogenes were capable of restricting the growth of S. enteritidis in the Peyer's patches. The ability of L. monocytogenes to induce nonspecific resistance was associated with the ability of this organism to cause an increase in the number of macrophages in the Peyer's patches.     

Hyperproduction of epithelium and its intravital desquamation into the lumen of the small intestine outside the “expulsion zone”

Investigation of total and histologically treated biopsy material of the mucous membrane of the small intestine of dogs with a complete intestinal fistula and of dogs with a by-passed length of small intestine revealed intensive formation of superfluous epithelial structures (outgrowths, continuous sheets of cells) in the region of the crypts and the base of the villi. Desquamation of these structures into the lumen of the intestine takes place outside the expulsion zone without disturbance of the intergrity of the covering villi. Less marked features of this process also were observed in control material. The results indicate the existence of yet another pathway of development whereby the crypt cell leaves the crypt-villus system as a component of branching and desquamated epithelial structures.Department of Experimental Pathology, N. V. Sklifosovskii Emergency Aid Research Institute, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 9, pp. 1133–1135, September, 1976     

Lymphoma of the small intestine

A series of eight small intestine lymphomas comprised two cases of follicular lymphoma (FL), one anaplastic large cell lymphoma (ALCL) ALK negative, and five cases of diffuse large B-cell lymphoma. The lymphomas were diagnosed by routine hematoxylin-eosin staining, immunohistochemistry and the FISH method for translocation t(14;18). Immunohistochemistry revealed that the diffuse large B-cell lymphomas were of the non-germinal center type (non GC-DLBCL). In most cases, the tumors formed solid well-circumscribed nodules or resulted in diffuse infiltration of the intestinal wall. In one case of follicular lymphoma, microscopic foci of tumor were found in the intestinal mucosa which spread far from the primary nodule and probably beyond the resection border. It is difficult to ascertain whether this phenomenon represents colonization of pre-existing non-neoplastic follicles by lymphoma or spreading of the tumor within the same tissue. In this case, surgical removal of the lymphoma is problematic.     

Leiomyosarcoma of the small intestine

In addition to the literature data the authors describe their own observation of small intestinal leiomyosarcoma. The case was interesting for an uncommon metastatic course and atypical histological appearance presenting difficulties for clinical diagnosis and morphological interpretation. The final diagnosis rested with electron microscopy.     

Angiosarcoma of the small intestine

Primary gastrointestinal angiosarcomas are very rare and those of the small bowel even more rare. We report a case which is the first in the literature from this part of the world. It presented in a 25-year-old woman with multiple dissemination and rapid fatality. Diagnosis was based on histological morphology using Hematoxylin and Eosin (H and E) stains, plus reticulin special stain to outline the vascular nature.     

Polyps of the small intestine

Polyps of the small bowel are rare compared to those of the colorectum. A correct histopathological diagnosis is crucial for the choice of subsequent treatment. This article reviews the most frequently found and some rare but distinct polyps and polyp-like lesions in the small intestine. Adenomas are the most commonly found polyps in the small intestine. Other polypoid lesions include Brunner gland hyperplasia, Brunner gland hamartoma, periampullary myoepithelial hamartoma and pyogenic granuloma. Adenomas are usually found in the distal portion of the duodenum, whereas, Brunner gland hamartoma and inflammatory polyps are noted in the proximal portion of the duodenum. The rare but distinct Peutz–Jeghers polyp and juvenile polyp are reviewed, including the associated hereditary autosomal dominant syndromes (i.e. Peutz–Jeghers and juvenile polyposis syndrome) of which these lesions are the phenotypic hallmarks. Finally, an extremely rare polyposis syndrome with unknown aetiology, i.e. Cronkhite–Canada syndrome, is described with documentation.     

Endocervicosis of the small intestine

A case of endocervicosis of the small intestine incidentally found as a mass lesion during a gastric bypass surgery is reported. No previous cases of intestinal endocervicosis have been reported in the literature.