Increased LFA-1 expression in intestines of rats with GVHD after small bowel transplantation.

Experimental graft-versus-host disease (GVHD) causes immune-mediated intestinal injury. The adhesion molecule lymphocyte function associated antigen-1 (LFA-1) is involved in leukocyte homing to areas of inflammatory injury. Our hypothesis was that LFA-1 is increased in the GVHD injured small bowel and colon.

Increased intestinal permeability in rats with graft versus host disease.

Background/aims: The study of graft versus host disease of the intestine has significant clinical relevance and may also be a model for other immune mediated intestinal diseases. There presently is no simple non-invasive test that can be used to evaluate graft versus host disease induced intestinal injury in humans or animal models. This study tested the hypothesis that graft versus host disease leads to an increase in host bowel permeability as assessed by the relative urinary excretion of orally administered lactulose and rhamnose.

Graft-versus-host disease after small bowel transplantation is associated with host colonic injury.

The present studies were undertaken to evaluate the histologic effects of graft-versus-host disease on the host colon after small bowel transplantation. Graft-versus-host disease was produced in six Lewis x Brown Norway F1 rats by performing vascularized, out-of-continuity small bowel transplants from parental Lewis donors. Host proximal and distal colon were sampled 14 days after operation when signs of graft-versus-host disease, including weight loss and splenomegaly, were present.

The association between PGE2 activity and mucosal permeability in proximal small bowel.

Little is known about the ontogeny of cyclooxygenase activity and synthesis of prostaglandins in the developing gastrointestinal tract. We tested the hypothesis that an age-related increase in cyclooxygenase as reflected in production of PGE2 in the proximal small bowel (PSB) is associated with the maturation of the mucosal barrier as determined by 51Cr-EDTA permeability. Cyclooxygenase activity in PSB of rats at 10, 22, 36, and 63 (adult) days of age was determined by the generation of PGE2 using specific radioimmunoassay.

Morphogenesis in the fetal rat proximal colon: effects of cytochalasin D.

Two major morphogenetic events, epithelial conversion and fold formation, occur in the proximal rat colon during the last week of gestation. To evaluate the role of actin microfilaments in these two developmental processes, explants from the proximal colon of 19 day fetal rats were cultured in the presence of vehicle (0.1% dimethylsulfoxide), 0.

Alterations in lectin binding in the proximal and distal colon of Sprague-Dawley rats with 1,2 dimethylhydrazine administration.

Sequential changes in rhodamine or fluorescein isothiocyanate-conjugated lectin binding of proximal and distal colonic crypts were studied during and after the administration of the 1,2 dimethylhydrazine (DMH). Five adult its unexposed to DMH or vehicle served as baseline controls. Tissue from normal appearing colon and tumor tissue was incubated with Ulex europaeus agglutinin 1 (UEA), Arachis hypogaea (PNA), Dolichos biflorus (DBA) and Griffonia simplicafolia 1 (GSA1).

Structural and enzymatic changes during colonic maturation in the fetal and suckling rat.

To assess correlations between cellular differentiation and enzymatic maturation in the developing rat colon, tissue from fetal, suckling, weanling, and adult rats was analyzed by electron microscopy and assayed for lactase, alkaline phosphatase, and sodium-potassium-stimulated adenosine triphosphatase activities. The proximal and distal colon were analyzed independently at all ages. All three enzymes were detected in the fetal colon when the cells were highly undifferentiated.

Central neurotensin affects rat gastric integrity, prostaglandin E2, and blood flow.

The aim of this study is to define the effect(s) of centrally administered neurotensin (NT) on gastric mucosal integrity, prostaglandin E2 (PGE2) generation, and blood flow during stress induced by cold-water restraint (CWR) in rats. Intracerebroventricular (icv) NT reduced macroscopic and microscopic damage. The former effect was dose dependent and was totally blocked by indomethacin pretreatment.

The effects of chronic ethanol administration on polyamine content during dimethylhydrazine-induced colorectal carcinogenesis in the rat.

Chronic ethanol (EtOH) consumption has been implicated as a co-carcinogen, selectively promoting rectal tumor formation. We studied the effects of EtOH consumption on tumor formation and polyamine content (putrescine, spermidine and spermine) in proximal and distal colon and rectum of Sprague-Dawley rats treated with the procarcinogen 1,2-dimethylhydrazine (DMH). Sixty-four adult male rats were pair fed nutritionally complete liquid diets with 36% of calories supplied as EtOH or isocaloric carbohydrates.

Cellular proliferation in proximal and distal rat colon during 1,2-dimethylhydrazine-induced carcinogenesis.

Sequential changes in proliferative parameters in proximal and distal colonic crypts were studied during 1,2-dimethylhydrazine-induced carcinogenesis using [3H]thymidine autoradiography as a probe. 1,2-dimethylhydrazine (20 mg/kg) and vehicle (ethylenediaminetetraacetic acid) control rats received weekly s.c.

Qualitative and quantitative changes in sialomucins during 1,2-dimethylhydrazine-induced colon carcinogenesis in the rat.

Regional differences in goblet cell glycoproteins have been demonstrated qualitatively and, to a limited extent, quantitatively in the normal adult colon. In disease states, alterations in these glycoproteins, particularly the sialoglycoproteins (SGs), have been reported. The present study defined parallel qualitative and quantitative changes in SGs in three colon regions during 1,2-dimethylhydrazine [(DMH) CAS: 540-73-8]-induced carcinogenesis.

Endocytosis and vesicular traffic in fetal and adult colonic goblet cells.

Structural and functional differences between adult and fetal colonic goblet cells have not been clearly defined. To compare the binding, uptake, and intracellular pathway of internalized apical membrane in fetal and adult goblet cells, cationic ferritin (CF) was used as a nonspecific probe. The initial distribution of membrane anionic sites was determined in segments of proximal and distal colon from fetal (18-22 days) and adult rats that were fixed prior to a 10-minute exposure to CF at 4 degrees C.

Lectin binding patterns in developing rat colon.

To evaluate qualitative changes in brush-border and goblet cell glycoconjugates during colonic development, rhodamine-conjugated lectins were applied to tissue from fetal (18-22 day), suckling (1-20 day), and weanling (22-26 day) rats. Tissue from the proximal and distal colon of each animal was incubated with Triticum vulgaris, Arachis hypogaea, Glycine max, or Ulex europeus agglutinin I. Formalin-fixed paraffin sections and unfixed frozen sections were coded, read blindly, and graded from negative (-) or weak (+) to intensely positive (4+).

Effects of enterally fed epidermal growth factor on the small and large intestine of the suckling rat.

Epidermal growth factor (EGF) has been shown to be present in the milk of several species, including the rat, and to have gastrointestinal effects when given parenterally or orally in pharmacologic doses. We investigated the effect of enteral EGF in physiologic doses on the small intestine and colon of suckling rats. Serum thyroxine (T4) levels were also measured.

Macromolecular transport in the fetal rat intestine.

Macromolecular barrier function of the fetal rat small intestine and colon was analyzed from 16 to 22 days gestation (birth). During this period the epithelium is converted from stratified to simple columnar. To assess permeability, horseradish peroxidase (HRP) was introduced by microinjection into the lumen or into the umbilical circulation.

Glucocorticoid receptors in isolated intestinal epithelial cells in rats.

There is evidence that glucocorticoid hormones influence a variety of epithelial cell functions in the small intestine. To exert their effect, glucocorticoids bind to cytoplasmic glucocorticoid receptors (GR), which, following translocation to the nucleus, stimulate mRNA transcription and then protein synthesis and ultimately trigger hormonal actions. To determine the distribution of GR in small intestinal villus and crypt cells, we measured GR activity in enriched villus and crypt cell fractions by use of [3H]dexamethasone.

Localization of carbonic anhydrase activity in the developing rat colon.

Carbonic anhydrase activity was localized histochemically by light and electron microscopy in the proximal and distal colon of developing rats. Fixed tissue was taken for normal morphology and carbonic anhydrase localization from fetal (20-22 days gestation), suckling (1-19 days postnatal), weanling (20-25 days postnatal), and adult rats. The proximal colon had distinct villi at birth which were diminished between days 5 and 11 postnatally.

Effects of prior adrenalectomy on postpneumonectomy lung growth in the rat.

The effects of adrenalectomy, with and without subsequent glucocorticoid replacement therapy, on postpneumonectomy compensatory lung growth in the rat were investigated. Male Sprague-Dawley rats (200-230 g) were subjected to no operation (UNOP), left pneumonectomy (PNX), or PNX preceded by bilateral adrenalectomy 5 days earlier (ADX/PNX). At 14 days post-PNX, when compensatory lung growth is normally complete in 200-g rats, right lung (RL) dry weights of PNX (263 +/- 6 mg, n = 26) and ADX/PNX (334 +/- 13 mg, n = 25) rats were increased 58 and 101%, respectively, relative to UNOP controls (166 +/- 5 mg, n = 10).

Epithelial differentiation in the fetal rat colon. I. Plasma membrane phosphatase activities.

During the last week of gestation of the fetal rat, the epithelium of the colon is rapidly remodeled. At 16 days a primitive stratified epithelium surrounds a small central lumen. Over the next 3 days, the main lumen extends narrow clefts down to the basal cell layer and small secondary lumina appear within the stratified epithelium between these clefts.

Glucagon and glicentin immunoreactive cells in human colon.

An immunohistochemical study of glucagon and glicentin immunoreactive endocrine cells in the human colon epithelium was performed. Serial sections and qualitative analysis show a cell population containing both immunoreactivities. However, there is another cell population exhibiting only an immunoreactivity with glicentin.

Development of gastrointestinal mucosal barrier. II. The effect of natural versus artificial feeding on intestinal permeability to macromolecules.

We have recently reported that the intestinal transport of intact macromolecules into the circulation decreases with age presumably due to maturation of mucosal barrier factors. To extend this observation and determine the effect of natural versus artificial feeding on maturation of intestinal mucosal "barrier function" we conducted experiments which assessed both macromolecular transport and epithelial cell morphology. To study barrier function, we gavage fed a physiologic quantity (100 mg) of bovine serum albumin (BSA) to weight-matched breast- and bottle-fed infant rabbits at 1 and 2 wk of age and quantitated intestinal macromolecular transport by measuring circulating plasma concentrations of the intact antigen 4 hr later.