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At least 775 records · Page 43Linked to original sources
PubMed1990

Early and long term effects of a model of intestinal autotransplantation on intestinal motor patterns.

The short and long term effects of a model of orthotopic jejunoileal autotransplantation on intestinal motility were studied in a model of four dogs that underwent autotransplantation of the entire jejunoileum. Serosal electrodes were placed to record intestinal motility patterns. Each dog was studied during fasting and after feeding early (two to six weeks) and late (14 to 17 weeks) after jejunoileal autotransplantation. During fasting, both the innervated duodenum and the autotransplanted jejunoileum showed the characteristic migrating motor complex (MMC) early after this model of transplantation, but the MMC in the two regions lacked temporal coordination. Late after transplantation, temporal reassociation of the MMC in the duodenum and jejunoileum occurred. Feeding a small meal (50 grams of liver) inhibited the MMC in the duodenum, but not in the jejunoileum either early or late after transplantation. These observations suggest that characteristic cyclic fasting motility patterns persist after this model of small intestinal transplantation and are dissociated temporally between innervated and transplanted regions for at least eight weeks, but then reassociate with time (greater than three months). Feeding a small meal did not induce a postprandial motor pattern in the transplanted region. The effects of these changes in motility on intestinal function remain unknown.

Animals↗
PubMed1993

Variations of intestinal motor activity in bladder replacements and in the intestine.

Urinary reservoirs are made from intestinal segments. The motor activity of the intestinal tract is regulated by hormonal and neurological controls. This study compares the motor activity of intestine in situ with those of a neobladder, following oral intake. The changes in motor activity before and after ingestion of standardized 570 Kcal meal were measured simultaneously in the duodenum and in the neobladder of 4 patients who underwent a Camey tubularized ileocystoplasty. Similar motor movements were produced in the graft and in the duodenum. Modifications due to oral intake were then measured in 14 patients with various types of urinary reservoirs (ilea, ileo-colic or colic; and tubularized or detubularized) by measuring the pressure inside the graft. After oral intake the compliance of the detubularized colic and ileocolic reservoirs was greater than that of ileal reservoirs, even after detubularization, since the motor activity and the basal pressure increased greatly in the tubularized or detubularized ileal bladders and much less in the detubularized colic and ileocolic bladders. It is well known that digestion is maximal in the second half of the night, therefore this link between intestinal and neobladder motor activity might explain one of several mechanisms involved in nocturnal increase in reservoir pressure and urine incontinence.

Eating↗
PubMed1997

Improvement of circulation in pedicled intestinal grafts: hemodynamics of the intestine after preparation of a sacrificial colonic graft.

BACKGROUND: To preserve postoperative digestive function in patients with esophageal carcinoma, jejunal or colonic segments on long vascular pedicles are transplanted and anastomosed between the esophagus and residual stomach. A postoperative survey showed pedicled jejunum transplantation to be superior in terms of digestive and absorptive functions, intraesophageal pressure, pH, and the quality of life of long-term postoperative survivors. Anastomotic leakage and necrosis of the pedicled intestinal graft are occasional complications; circulatory disorders of the pedicled intestine are a probable cause of both complications. STUDY DESIGN: To simulate pedicled jejunum transplantation, we prepared pedicled colonic segments from dogs and measured blood flow volume at the cut end of the oral side of the colonic segments using the hydrogen clearance method and at the nutrient vascular pedicle with an electromagnetic blood flowmeter. RESULTS: Resection of excess colon increased blood flow volume per unit weight of the colonic segment. CONCLUSIONS: It is essential to resect excess intestine and keep only the minimum length of pedicled intestinal graft needed for reconstruction of the esophagus.

Anastomosis, Surgical↗
PubMed2001

Mono-N-carboxymethyl chitosan (MCC), a polyampholytic chitosan derivative, enhances the intestinal absorption of low molecular weight heparin across intestinal epithelia in vitro and in vivo.

The synthesis and evaluation of mono-N-carboxymethyl chitosan (MCC) as an intestinal permeation enhancer for macromolecular therapeutics is presented. MCCs were synthesized from two different viscosity grade chitosans to yield both high and low viscosity grade products. These MCCs were tested on Caco-2 cells for their efficiency to decrease the transepithelial electrical resistance (TEER) and to increase the paracellular permeability of the anionic macromolecular anticoagulant low molecular weight heparin (LMWH). For in vivo studies, LMWH was administered intraduodenally with or without MCC to rats. Both types of experiments were performed at pH 7.4. Results show that both viscosity grade MCCs managed to significantly decrease the TEER of Caco-2 cell monolayers when they were applied apically at concentrations of 3-5% (w/v). Transport studies with Caco-2 cells revealed substantial increases of LMWH permeation in the presence of both viscosity grade MCCs compared with controls. In rats, 3% (w/v) low viscosity MCC significantly increased the intestinal absorption of LMWH, reaching the therapeutic anticoagulant blood levels of LMWH. Both in vitro and in vivo results indicate that the polyampholytic chitosan modification MCC is a suitable and functional polymer for the delivery and intestinal absorption of anionic macromolecular therapeutics like LMWH.

Animals↗
PubMed1994

Intestinal absorption pathway of gamma-aminobutyric acid in rat small intestine.

Intestinal absorption of gamma-aminobutyric acid (GABA), as a model compound for gamma-aminoacids, has not been extensively studied from the kinetic viewpoint. Since data from our laboratory suggested that some competition arises between intestinal absorption of beta-alanine and GABA and since our intent was to maintain the aqueous stagnant diffusion layer in order to approach absorption tests to in vivo physiological conditions, a rat jejunum in situ study was undertaken in order to gain an insight into the mechanism of GABA absorption. In the present paper, results from assays using isotonic perfusion solutions with starting GABA concentrations ranging from 1 to 50 mM are reported. They show that the intestinal absorption of the gamma-aminoacid can be apparently described as a specialized transport mechanism which obeys Michaelis-Menten and first-order kinetics. Parameter values found were Vm = 13.99 +/- 2.37 mM h-1, Km = 3.87 +/- 0.63 mM, and ka(passive) = 0.362 +/- 0.120 h-1. Through the perfusion of 5 mM beta-alanine solutions containing variable concentrations of GABA (from 5 to 50 mM), a partially competitive inhibition of beta-alanine absorption was apparently characterized.

Alanine↗
PubMed2005

Protein from intestinal Eimeria protozoan stimulates IL-12 release from dendritic cells, exhibits antitumor properties in vivo and is correlated with low intestinal tumorigenicity.

The small intestine (SI) of vertebrates exhibits low tumorigenesis and rarely supports metastatic growth from distant tumors. Many theories have been proposed to address this phenomenon, but none has been consistently supported. One candidate mechanism is that the vast immunologic compartment of the SI provides a heightened level of tumor immunosurveillance. Consistent with this, we have identified a molecule of low abundance from bovine SI that has the hallmarks of a potent immunostimulant and may be associated with the natural suppression of cancer in the intestinal tract. The protein originates from an endemic gut protozoan, Eimeria spp., and is homologous to the antigen 3-1E previously isolated from the avian apicomplexan E. acervulina. We show here that it is a very potent stimulator of IL-12 release from dendritic cells, upregulates inflammatory modulators in vivo (IL-12, MCP-1, IL-6, TNF-alpha and INF-gamma) and has antitumor properties in mice. In addition, it is synergistic in vitro with anti-CD40 antibody, IFN-gamma, IL-4 and GM-CSF; is active across species barriers in vivo; and has no observable toxicity. Based on these activities, we speculate that it is an inducer of protozoan-targeted innate immunity, which may explain its potential benefit to the intestinal tract and potency as an agent in cancer immunotherapy.

Amino Acid Sequence↗
PubMed1981

Intestinal absorption mechanism of amphoteric beta-lactam antibiotics I: Comparative absorption and evidence for saturable transport of amino-beta-lactam antibiotics by in situ rat small intestine.

The disappearance of various beta-lactam antibiotics from in situ rat small intestinal loops was studied at pH 7.4. For monobasic penicillins, despite the wide variety of apparent partition coefficients in isobutyl alcohol-water, the disappearance from the jejunal loops was almost 30% (+/- 5% SD). On the other hand, the disappearance of amphoteric derivatives of penicillins and cephalosporins having very low lipid solubility varied widely between 12 and 80%. The peak blood levels after intraduodenal administration to the rats correlated well with the extent of disappearance of amphoteric penicillins from the intestinal loops. Absorption studies utilizing in situ intestinal loops were performed at variable dose ranges to yield a clear dose-dependent disappearance. It is suggested that certain carrier-mediated transport systems underlie the absorption mechanism of amphoteric beta-lactam antibiotics.

Animals↗
PubMed1986

Intestinal absorption of 5-fluorouracil and its alkylcarbamoyl derivatives in the rat small intestine.

The intestinal absorption of 5-fluorouracil (1) and its alkylcarbamoyl derivatives possessing various lipophilic pro-moieties including the butylcarbamoyl, hexylcarbamoyl, octylcarbamoyl, and nonylcarbamoyl groups, was investigated in the rat using both in situ and in vitro techniques. All compounds showed greater apparent partition coefficients and lipophilic indices (k') (by HPLC) and lower solubilities in water than 1. Although enhancement of uptake by the everted intestine in vitro was observed when the alkylcarbamoyl chain length was increased, the appearance of the prodrugs in the mesenteric vein in the in situ intestinal loop (complete venous collection) was decreased and sustained. The conversion of alkylcarbamoyl derivatives to 1 was noted in the absorption process.

Animals↗
PubMed1999

Small intestinal UDP-glucuronosyltransferase sheUGT1A07: partial purification and cDNA cloning from sheep small intestine.

A phenol UDPglucuronosyltransferase (UGT) was partially purified, and the cDNA encoding the isoform was cloned and sequenced from sheep small intestine. The purified preparation containing a one major band (57 kDa) and one minor band (50 kDa) revealed high activities toward xenobiotics such as 1-naphthol (1-NA), 4-nitrophenol, and 4-methylumbelliferone. The preparation, however, had only little activity toward 4-hydroxybiphenyl and no activity toward bilirubin, suggesting that the preparation contains UGT1 isoforms. The NH2-terminal amino acid sequence of the major band was determined to be Gly-Lys-Leu-Leu-Val-Val-Pro-Met-Asp-Gly-Ser. A full-length UGT cDNA was obtained by reverse transcription-polymerase chain reaction with the degenerated 5'-primer from the NH2-terminal amino acid sequence of the purified major one and rapid amplification of cDNA ends from sheep small intestine. The cloned cDNA named sheUGT1A07 by amino acid similarity has a NH2-terminus sequence identical to that of the purified major one. Another phenol UGT cDNA named sheUGT1A6 was also cloned from sheep liver. sheUGT1A6 was expressed mainly in the liver, whereas sheUGT1A07 mRNA was expressed almost only in the alimentary organs, suggesting that sheUGT1A6 plays a role as a general drug metabolizing UGT isoform in the liver and sheUGT1A07 plays important role in the xenobiotics glucuronidation in the sheep small intestine.

Amino Acid Sequence↗
PubMed1995

Somatostatin-, vasoactive intestinal peptide-, and granulin-like peptides isolated from intestinal extracts of goldfish, Carassius auratus.

Three new peptides were originally isolated from intestinal extracts of goldfish. They were structurally related with somatostatin, vasoactive intestinal peptide (VIP), and granulin (GRN) and thus termed goldfish somatostatin (gSS-28), gVIP, and gGRN, respectively. The primary structures of these peptides were determined as: SVESSNHLPA 10RERKAGCKNF20YWKGFTSC for the gSS-28; HSDAVFTDNY10SRYRKQMAAK20KYLNSVLA-NH2 for the gVIP, and VIHCDSSTIC10 PDGTTCCLSP20YGVWYCCPFS30MGQCCRDGIH40CCRHGYHCDS50TSTHCLR for the gGRN. The amino acid sequence of the gSS-28 was more similar (79-86% similarity) to somatostatins obtained in anglerfish, flounder, and sculpin, but far (21% similarity) from the catfish somatostatin, whereas goldfish and catfish belong to the same superorder. The structure of the gVIP was closely related to that of the cod VIP; only one residue (Tyr13) being substituted for Phe13 in the cod VIP. Comparing amino acid sequences of VIPs obtained in various vertebrates, the primary structure of this peptide was revealed to be relatively well conserved among vertebrates. In addition, the dose-response curve for the effect of gVIP on the short-circuit current (Isc) across the eel intestine was similar to that of human VIP, suggesting that VIPs in vertebrates have similar effect. The amino acid sequence of gGRN was 96% identical to that of carp GRN-1; only two residues (Ser6-Ser7) being substituted for Ala6-Ala7 in the carp GRN-1. The physiological significance of these peptides is discussed.

Amino Acid Sequence↗
PubMed1992

Membrane conductance and cell volume changes evoked by vasoactive intestinal polypeptide and carbachol in small intestinal crypts.

We have used the perforated-patch whole-cell recording mode of the patch-clamp technique to monitor membrane potential and measured cell volume changes by image analysis, to determine the nature of the response to secretagogues of isolated whole guinea-pig small-intestinal crypts. Vasoactive intestinal polypeptide (VIP) produced a dose-dependent depolarisation (EC50 = 30 nM) and an increase in membrane conductance that could be potentiated by carbachol. Similar depolarisations were observed with forskolin. The depolarisation induced by 100 nM VIP was smaller when pipette [Cl-] was 60 mM than when it was 145 mM, suggesting an effect through Cl- conductance activation. Carbachol alone produced a hyperpolarisation (EC50 = 2 microM). The Cl- channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) produced a small hyperpolarization. When VIP was added in the presence of NPPB, the depolarisation was observed instead, consistent with the parallel activation of a K+ conductance. Both carbachol (100 microM) and VIP (100 nM) induced a 25%-30% shrinkage of crypts, which was maximal 8 min after addition of the secretagogue. The induced shrinkage was sustained in the continued presence of agonist and was reversed upon washout. Shrinkage induced by the agonists was abolished by increasing extracellular K+ from 6 mM to 20 mM and was inhibited partially in the presence of 100 microM anthracene-9-carboxylic acid in the bath. The decrease in volume induced by 100 nM VIP was totally abolished in the presence of 100 microM NPPB. The results are consistent with the view that both VIP and carbachol induce secretion in small-intestinal crypts.

Animals↗
PubMed1980

Damage of rat small intestine induced by ethanol. Effect of ethanol on fecal excretion of intestinal alkaline phosphatase.

Single administration of ethanol or alcoholic beverages (5g ethanol/kg body weight) induces a decrease of the 24h excretion of fecal intestinal alkaline phosphatase (I-AP) activity of 28% (P less than 0.05) in comparison to controls (0.9% saline). Administration of higher amounts of 20% (v/v) ethanol (8g/kg body weight on 3 consecutive days) yields a decrease of fecal I-AP excretion up to 82% (P less than 0.005) in comparison to controls (saturated glucose solution). The interpretation of these results as a toxic effect of ethanol to small intestinal mucosa was supported by measurement of enzymatic activity in the small intestinal mucosa and by morphometric data.

Alkaline Phosphatase↗
PubMed1994

Effects of artificial ileocolonic sphincter on motility in intestinal remnant following subtotal small intestinal resection in the dog.

We studied the effects of a sphincter substitute on motility in the intestinal remnant following an extensive distal intestinal resection. Two groups of adult dogs were studied; each underwent a 75% resection of the distal small intestine, and in one group a nipple valve was fashioned at the distal end of the remnant. Nutritional status, absorptive function, motility, and transit were studied over a three-month period. While the nipple valve animals had less diarrhea, steatorrhea, and hypoalbuminemia, motor activity and transit were similar in both groups. Thus, in both groups, fasting motor activity was dominated by clusters of phasic pressure activity. (Cluster frequency, per hour, mean +/- SE, resection vs resection with nipple valve: 4.8 +/- 1.05 vs 3.58 +/- 0.54, NS). We conclude that the beneficial effects of a sphincter substitute in ameliorating the short bowel syndrome in this dog model are not related to any modification of the motor response to resection but may simply reflect those of a low-grade mechanical obstruction.

Animals↗
PubMed1988

Expression of histamine and vasoactive intestinal peptide (VIP) receptors in immortalized rat fetal intestinal cells.

Four intestinal cell lines derived from rat fetuses at 19 days of gestation were successfully propagated after electroporation in the presence of different recombinant DNAs containing the viral oncogenes E1A from Adenovirus 5 and large T from SV40 or Polyoma. These immortalized intestinal cells, designated SLC, possess several properties observed in the parent cells of this tissue, including the expression of cytoplasmic villin, enkephalinase and retention of VIP receptors. In contrast, histamine elevated cAMP levels in the SLC cell lines only. The data suggest that the transfection of fetal rat intestinal cells by E1A and large T is associated with the induction of functional histamine receptors coupled with the Gs/Gi regulatory proteins of adenylate cyclase.

Animals↗
PubMed1975

Intestinal lipid absorption: evidence for an intrinsic defect of chylomicron secretion by normal rat distal intestine.

Intracellular triglyceride accumulation and delayed chylomicron secretion were demonstrated in distal but not in proximal rat intestine following prolonged steady state fat absorption. After 1 and 4 hr of intraduodenal triolein infusion, the mucosal triglyceride content in distal intestinal segments was greatly increased compared with proximal segments. Electron microscopy at each time interval disclosed greater quantities of lipid droplets within the distal cells and these were much larger than the intracellular droplets in the proximal cells, some attaining an enormous size (9000 mum). When proximal and distal cells were compared at intervals after cessation of a 4 hr triolein infusion, the differences in intracellular lipid accumulation were also evident because, even after 6 hr the distal cells were still filled with large droplets, whereas the proximal cells were almost devoid of fat. These results indicate a basic cellular difference between proximal and distal intestine in the processing of fat and, in contrast to current concepts, suggest that defective chylomicron secretion is not necessarily associated with limited B-apoprotein availability.

Animals↗
PubMed1993

Changes in fatty acid desaturation in hepatic and intestinal tissues induced by intestinal resection.

We have studied the activities of delta 9, delta 6 and delta 5 desaturases in rat liver and jejunum when the entero-hepatic circulation was interrupted by either 50 or 75% intestinal resection. Desaturase activities in caecal mucosa were also determined in control and operated rats. Distal small bowel resection significantly altered the activities of desaturase enzymes in liver, jejunum and caecum. Thus, the delta 9 desaturase activity was lower in hepatic microsomes from operated animals, and this decrease was not related to the extent by which the intestine was removed. However, a significant increase in both delta 6 and delta 5 desaturases was found in these animals compared to sham-operated rats, the increase in both desaturases being higher after 75% than after 50% intestinal resection. The activities of delta 9 and delta 5 desaturases were significantly increased in jejunal mucosa of resected rats. The activity of delta 6 desaturase was increased only in 50% resected-animals. An increase in delta 6 desaturase activity was observed in caecal mucosa after resection, together with a decrease in delta 9 desaturase and no change in delta 5 desaturase activities. Enzyme activities were highest in the liver relative to the activity in jejunal and caecal homogenates. In sham rats, the caecal mucosa showed higher delta 9 and delta 6 but lower delta 5 desaturase activities than in jejunal mucosa.

Animals↗
PubMed1982

The role of intestinal bacteria in gallstone formation in animal model. A study on biliary lipid composition and bile acid profiles in bile, small intestinal contents and feces of clostridium butyricum Miyairi No. 588 monocontaminated mice.

Contradictory results in the studies on experimental gallstone formation using conventional and germfree mice have been reported. To study the role of bacteria in gallstone formation in the animal model JCL:ICR male germfree mice were monocontaminated with Clostridium butyricum MIYAIRI No. 588. Gallstone formation, biliary lipid composition and bile acid profiles in the bile, small intestinal contents and feces were analyzed after feeding the diet containing cholesterol and cholic acid. The rate of gallstone formation in the monocontaminated mice (38%) was less than that in the germfree mice (100%). The relative concentrations of biliary lipids of the two groups were located out of the micellar zone on the triangular co-ordinates by Admirand and Small. The bile acid concentrations in the small intestine and fecal excretions in the monocontaminated mice were higher than in the germfree mice. The composition as well as the mode of conjugation of the bile acids did not differ significantly between the two groups. The infestation of bacteria in the intestine enhanced the excretion of bile acids and inhibited the gallstone formation in mice, in which direct metabolic activity by bacterial enzymes on bile acid did not seem necessary to exert such effect.

Animals↗
PubMed1991

Intestinal malrotation: the role of small intestinal dysmotility in the cause of persistent symptoms.

To investigate the possibility that small intestinal dysmotility is a cause of long-standing and persistent symptoms in patients with malrotation, we retrospectively reviewed 94 patients operated on for intestinal malrotation. In 50 patients operated on during the neonatal period, associated abnormalities were common (24%) and all presented with obstructive symptoms; only three (6%) had continuing mild symptoms the postneonatal period (aged 1 month to 1 year), five of whom (22%) had other abnormalities. Recurrent vomiting was the most common presentation (11/23); only 5 patients (21%) had acute obstruction. Response to operation was good in 18 (78%) and two had persistant symptoms; both died. Twenty-one patients presented beyond infancy (aged greater than 1 year), only 19 of whom had symptoms of less than 2 months' duration. Eight (47%) of those with long-standing symptoms had no relief from operation. Small bowel motility was recorded manometrically in 4 patients with long-standing symptoms. The findings suggest that small intestinal dysmotility may be common in patients with malrotation and persistant symptoms.

Adolescent↗