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PubMed1959

Ionic transfer across the isolated frog large intestine.

The unidirectional fluxes of sodium, chloride, and of the bicarbonate and CO(2) pair were determined across the isolated large intestine of the bullfrog, Rana catesbiana. The isolated large intestine of the frog is characterized by a mean transmembrane potential of 45 mv., serosal surface positive with respect to mucosal. The unidirectional sodium flux from mucosal to serosal surface was found to be equal to the short-circuit current, thus the net flux was less than the simultaneous short-circuit current. This discrepancy between active sodium transport and short-circuit current can be attributed to the active transport of cation in the same direction as sodium and/or the active transport of anion in the opposite direction. The unidirectional fluxes of chloride and the bicarbonate and CO(2) pair revealed no evidence for active transport of either anion. A quantitative study of chloride fluxes at 45 mv. revealed a flux ratio of 1.8 which is considerably less than a ratio of 6 expected for free passive diffusion. It was concluded that a considerable proportion of the isotopic transfer of chloride could be attributed to "exchange diffusion." Study of the electrical properties of the isolated frog colon reveals that it can be treated as a simple D. C. resistance over the range of -20 to +95 mv.

Animals↗

PubMed2000

5-HT(4) receptors on cholinergic nerves involved in contractility of canine and human large intestine longitudinal muscle.

5-HT(4) receptors mediate circular muscle relaxation in both human and canine large intestine, but this phenomenon alone can not explain the improvement in colonic motility induced by selective 5-HT(4) receptor agonists in vivo. We set out to characterize 5-HT(4) receptor-mediated effects in longitudinal muscle strips of canine and human large intestine. Electrical field stimulation (EFS) was applied providing submaximal isotonic contractions. L-NOARG (0.1 mM) was continuously present in the organ bath to preclude nitric oxide-induced relaxation to EFS. The selective 5-HT(4) receptor agonist prucalopride (0.3 microM) enhanced EFS-evoked contractions, that were antagonized in both preparations by the selective 5-HT(4) receptor antagonist GR 113808 (0.1 microM). The prucalopride-induced increase was present in canine ascending and descending colon, but absent in rectum. Regional differences in response to prucalopride were not observed in human ascending and sigmoid colon and rectum. Incubation with atropine (1 microM) or tetrodotoxin (0.3 microM) inhibited EFS-induced contractions, which were then unaffected by prucalopride (0.3 microM) in both tissues. In the presence of methysergide (3 microM; both tissues) and granisetron (0.3 microM; only human tissues), 5-HT (0.3 microM) enhanced EFS-induced contractions, an effect that was antagonized by GR 113808 (0.1 microM). In the presence of atropine or tetrodotoxin, EFS-induced contractions were inhibited, leaving 5-HT (0.3 microM) ineffective in both preparations. This study demonstrates for the first time that in human and canine large intestine, 5-HT(4) receptors are located on cholinergic neurones, presumably mediating facilitating release of acetylcholine, resulting in enhanced longitudinal muscle contractility. This study and previous circular muscle strip studies suggest that 5-HT(4) receptor agonism facilitates colonic propulsion via a coordinated combination of inhibition of circumferential resistance and enhancement of longitudinal muscle contractility.

Animals↗

PubMed1993

Digestion of polysaccharides and other major components in the small and large intestine of pigs fed on diets consisting of oat fractions rich in beta-D-glucan.

The digestibility of polysaccharides and other major components and the metabolic response of the microflora in the small and large intestines to oat diets varying in mixed linked beta(1-->3; 1-->4)-D-glucan (beta-glucan) were studied in experiments with ileum-cannulated pigs. The oat fractions for diets were prepared in a dry milling process in which oat groats were milled into two endosperm fractions (oat flour 1 and oat flour 2) and oat bran. The digestibility of polysaccharides and the metabolic response of the microflora were followed for the two contrasting diets, oat flour 1 and oat bran, from ingestion to excretion while the digestibility of oat groats and oat flour 2 were estimated only at the ileum and in faeces. There was no degradation of beta-glucan from either oat flour 1 or bran in the stomach and the first, middle and distal thirds of the small intestine (average digestibility approximately 0), while in the terminal ileum digestibility increased to 0.30 to 0.17 respectively. The digestion of starch in the first third of the small intestine was lower for the high-beta-glucan oat-bran diet (0.49) than for the low-beta-glucan flour diet (0.64). However, digestibility differences between the two diets levelled out as the digesta moved aborally in the small intestine and the digestibility at the terminal ileum was almost complete (0.970-0.995) for all diets. Oat non-starch polysaccharides (NSP) were an easily digestible energy source for the microflora in the large intestine less than 13% of dietary NSP being recovered in faeces. The bulk of beta-glucan which survived the small intestine was degraded in the caecum and proximal colon while arabinoxylan was more slowly degraded. The amount of residues passing the ileo-caecal junction has little impact on the density of micro-organisms in the large intestine, which on the flour and bran diets were in the range of 10(10)-10(11) viable counts/g digesta, but a high impact on the activity of the flora in colon. Oat bran resulted in a higher proportion of butyric acid in large intestinal content compared with the flour diet. The faecal bulking effect of oat bran was mainly caused by an increased excretion of protein and fat, presumably of bacterial origin. Of all the diets tested the oat-bran diets had the lowest digestibilities of protein and fat at the terminal ileum and in the faeces.

Animals↗

PubMed1996

[Role of non spore-forming anaerobes in the formation of microbial landscape of the large intestine in patients with inflammatory processes at different sites].

Clinical microbiological techniques were used to study 300 patients with clinically verified urinary infections and chronic intestinal diseases. It was ascertained that examining the large intestinal content in average statistical groups of patients with inflammatory processes at various sites cannot objectively characterize the presence or absence of clinical manifestations of gastrointestinal diseases. The pathogenetic factors that predispose to the development of intestinal diseases are lower phagocytic activity, decreased complement and deficiency of B lymphocytes and IgA. The concentrations of IgM, IgG, secretory IgA and protein, as well as those of B. bifidum in the large intestinal content may serve as an additional diagnostic criterion for evaluating the mucosa of the ecological niche.

B-Lymphocytes↗

PubMed2000

Feasibility study on endoscopic suture with the combination of a distal attachment and a rotatable clip for complications of endoscopic resection in the large intestine.

BACKGROUND AND STUDY AIMS: Endoscopic resection has been more frequently performed for increasingly larger intramucosal tumors of the large intestine in recent years. It is reasonable to expect that the larger the resected mucosal surface, the greater is the likelihood of complications such as bleeding or perforation. The aim of this study was to explore the feasibility of endoscopic suture with a distal attachment and a rotatable clip-fixing device for complications of endoscopic resection in the large intestine. PATIENTS AND METHODS: The study population consisted of 15 patients who underwent endoscopic clipping therapy following endoscopic resection for intramucosal tumors of the large intestine. With a distal attachment fitted to the distal end of the endoscope, the optimal position for clipping was ensured by pressing the intestinal wall and deflating the intraluminal air little by little. With a rotatable clip-fixing device, the resection site was endoscopically sutured clip by clip. RESULTS: Tumors were of the laterally spreading tumor type in six patients, small sessile polyps in three, and pedunculated polyps in six. The complications consisted of bleeding in 12 patients, overt perforation in one, and latent perforation in two; 14 of the 15 patients underwent successful suturing by this method. The number of clips used ranged from two to seven (mean 4.4). No patients had further complications after the treatment. CONCLUSION: We conclude that endoscopic suture with the combination of a distal attachment and a rotatable clip-fixing device is very useful for complications of endoscopic resection in the large intestine.

Colonic Polyps↗

PubMed1978

[The influence of chenodeoxycholic acid on the concentrations of nonsulfated bile acids in the small and large intestinal mucosa of rats (author's transl)].

In male Wistar rats nonsulfated bile acids of small and large intestinal wall and feces are analysed after 2, 5, 9 and 14 days of oral administration of 20 or 90 mg chenodeoxycholic acid (CDCA)/kg. Development of body, intestinal, and fecal weights is assessed. A transient reduction of daily body weight gain and small and large intestinal weights is compensated after 14 days. Fecal weights are above controls under 20 mg/kg, below controls under 90 mg/kg. Containing about 2 mg, i.e. nearly 4% of the bile acid pool, the intestinal wall holds four times more bile acids than the liver. Under CDCA administration bile acid concentrations in the small intestinal wall and feces rise, and remain almost unchanged in the colonic wall. Changes after CDCA administration suggest that bile acid absorption is accompanied by an increase in mucosal bile concentration. In the colonic wall the increase in bile acid concentration after CDCA administration correlates with the passive permeability coefficient.

Animals↗

PubMed1987

Excitatory innervation of the rabbit rectococcygeus muscle by enteric nerves from the terminal large intestine.

The rectococcygeus muscle extends from the longitudinal layer of the external muscles of the terminal colon, anchoring the large intestine to the coccygeal vertebrae. The muscle is thought to assist the colon during defaecation, drawing the large intestine partly into the pelvic cavity. In the rabbit, many fine nerves run between the wall of the colon and a ganglionated nerve plexus on the ventral face of the rectococcygeus muscle. Extracellular recordings of evoked and spontaneously occurring multiunit discharges from these nerve bundles indicated that they may take their origin from the enteric nervous system of the large intestine. Enteric nerves (as we have called them) conducted bursts of spontaneously occurring multiunit discharges, each burst associated with a twisting movement of the rectococcygeus and the colon. Electrical stimulation of enteric nerves elicited cholinergically mediated contractions of the rectococcygeus; however, nerve stimulation failed to elicit relaxation of muscle tone induced by carbachol. Therefore, enteric nerves appeared to supply the rectococcygeus with an excitatory innervation only. These excitatory nerves appeared to remain uninterrupted by a ganglion synapse as they travelled to the rectococcygeus. Stimulation of enteric nerves caused the left and right hemirectococcygeal muscle strips to twist and deform the colo-rectal region to which they were attached. From these results, it is suggested that the rectococcygeus may delay the movement of luminal contents from colon to rectum by forming a weak valve which partially occludes the colo-rectal region. The enteric nerves to the rectococcygeus may assist in the maintenance of continence.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

The distribution of inhibited early third stage Cyathostominae larvae in the large intestine of the horse.

The distribution of inhibited early third stage Cyathostominae larvae in different parts of the large intestine of the horse was studied in 20 Shetland ponies necropsied in autumn 1982, 1983 and 1984. The location of the larvae in the large intestinal wall was studied by histological examination of the intestines of the eight ponies from 1984. Inhibited larvae were located predominantly and more or less equally in the caecum and the ventral colon. Generally fewer early L3 were in the dorsal colon. In 1984 a considerable proportion (mean 17%, range 9.7-36.9%) of the inhibited larvae was found in the contents instead of in the mucosa of the large intestine, despite a housing period under helminth free conditions of 5 weeks. These larvae probably had been overlooked in 1982 and 1983. In sections cut from the intestinal wall most early L3 were found in the lamina propria. They were surrounded by a small fibrous capsule. Some were found in the lumen or epithelium of the Lieberkühn's crypts and a small proportion in the submucosa.

Animals↗

PubMed2000

[Impact of lactic acid fermentation in the large intestine on acute lactic acidosis in cattle].

Microbial and fermentation changes in the ingesta of the large intestine and their influence on the pathogenesis of acute lactic acidosis were studied in 4 cows fitted with permanent cannulas in the ileum and cecum. Feed mixture containing 65% of maize was infused into the cecum for several days in amounts of 2 and 4 kg per day. The daily amount was divided in 8 equal portions and given with 3 l of warm physiologic saline solution. During the period of ad libitum feeding of hay, the pH values in cecal digesta were 7.4 to 7.6 and the amount of total volatile fatty acids 40-60 mmol/kg with high molar percentage (87-90 mol%) of acetic acid. As to lactic acid only the L(+) lactic isomer was found in a concentration of about 0.4 mmol/kg. Infusion of low amounts of starch induced mild lactic acid fermentation in the cecum associated with a pronounced increase in the concentration of L(+) and D (-) lactic acid to peak levels of 80 +/- 10 mmol/kg and 7 +/- 1 mmol/kg, respectively. Lactic acid fermentation ceased within 2 to 3 days indicating that the gut microflora had adapted to the starch infusion. Slight decreases of blood pH and bicarbonates in blood as well as a moderate increase of netto acid-base excretion in urine indicated mild changes of acid-base balance, but clinically no pathological symptoms were observed. Higher amounts of infused starch caused pronounced lactic acid production in the large intestine which persisted throughout the experiment. Peak L(+) and D(-) lactic acid concentration in cecal digesta reached on the average 137 +/- 16 mmol/kg and 45 +/- 7 mmol/kg respectively. Significant decreases of blood pH values from 7.41 +/- 0.02 to 7.18 +/- 0.08 (P < 0.001), actual bicarbonate from 28.2 +/- 3.2 to 11.0 +/- 2.6 mmol/l (P < 0.001) and base excess from 3.9 +/- 3.6 to -15.2 +/- 3.8 mmol/l (P < 0.001) were observed. D (-) lactic acid concentration in blood increased to 3.2 +/- 0.4 mmol/l, but L(+) lactic acid values remained unchanged under 1 mmol/l. Clear clinical symptoms of indigestion and intoxication characterized by severe inappetence, ruminal stasis and general weakness were also observed. Typical clinical symptoms of disease as well as blood and urine changes in acid-base balance indicated that lactic acid fermentation in the large intestine contributes considerably to the pathogenesis of acute ruminant lactic acidosis.

Acid-Base Equilibrium↗

PubMed1993

Escherichia coli F-18 phase locked 'on' for expression of type 1 fimbriae is a poor colonizer of the streptomycin-treated mouse large intestine.

Escherichia coli F-18, a human fecal isolate, makes type 1 fimbriae in vitro and in the streptomycin-treated mouse large intestine in vivo, and is an excellent colonizer of the cecal mucus layer in the streptomycin-treated mouse large intestine. E. coli F-18(pPKL91) harbors an extra fimB gene on a parB stabilized pPBR322 plasmid and is therefore phase-locked 'on' such that all cells express type 1 fimbriae. E. coli F-18(pPR633) contains essentially the same plasmid minus the fimB gene and in L-broth about 30% of the cells express type 1 fimbriae. When fed alone to streptomycin-treated mice, E. coli F-18(pPKL91) colonized the large intestine at about 10(7) cfu/g of feces. However, when simultaneously fed with E. coli F-18(pPR633) at either high (10(10) cfu), or low doses (10(4) cfu), E. coli F-18(pPKL91) was a poor colonizer dropping to a level of between 10(2) and 10(3) cfu/g of feces. When given enough time to establish the state of colonization (10 days), E. coli F-18(pPKL91) persisted in feces in high numbers despite subsequent challenge by E. coli F-18(pPR633). Moreover, although both E. coli F-18(pPR633) and E. coli F-18(pPKL91) grew equally well in cecal mucus in vitro, E. coli F-18(pPR633) traveled through a layer of cecal mucus in vitro much faster than E. coli F-18(pPKL91). Together, the data suggest that type 1 fimbriated cells are at a disadvantage in initiating the colonization state because they have difficulty entering the mucus layer of the intestine as rapidly as non-fimbriated cells. The data also point to the possible biological significance of type 1 fimbrial phase-variation in the mouse large intestine.

Animals↗

PubMed1990

[Clinico-morphological aspects and treatment of polyps associated with cancer of the large intestine].

Among 218 patients with cancer of the large intestine, in 56 (25.7%), a tumor was associated with single, or multiple polyps. In morphological study, considerable dysplasia of glandular epithelium was revealed in 43.7%, and malignization--in 9.2% of accompanying polyps. Considering association of cancer with adenomas as one of the forms of large intestinal polyneoplasia, the authors recommend to perform in such patients typical radical operations in combination with endoscopic polypectomy, and extend the volume of resection only in polyp malignization with invasion of the tela submucosa, or diffuse polyposis.

Adenoma↗

PubMed1986

The number and distribution of lymphoid follicles in the human large intestine.

The density of mucosal lymphoid follicles has been determined in the large intestines of five sudden death victims. The specimens were fixed in acetic acid which made the follicles visible macroscopically. The estimated total number of follicles in the large intestine ranged from 12761 to 18432. The average density of follicles was 18.4 per cm2 in the caecum, 15.0 per cm2 in the colon and 25.4 per cm2 in the rectum. These results indicate that the density of lymphoid follicles has been grossly underestimated in the past where three to five follicles per cm2 have been accepted as normal. The cause for this major discrepancy is discussed as is its bearing on the diagnosis of lymphoid hyperplasia.

Adolescent↗

PubMed1988

The possibility of nonpolypoid carcinogenesis in the large intestine as inferred from frequencies of DNA aneuploidy of polypoid and crater-shaped carcinomas.

DNA ploidy patterns were studied by cytofluorometry in 60 cases of crater-shaped invasive carcinoma and 30 cases of polypoid tumor (severe dysplasia or submucosally invasive carcinoma located in the pedunculated, semipedunculated, or sessile polyp) of the large intestine. The data were compared with 20 cases of intramucosal differentiated (or intestinal type) adenocarcinoma of the stomach, with special reference to their macroscopic shape and frequency of DNA aneuploidy. DNA aneuploidy was found in 77% of the crater-shaped carcinomas and in 17% of the polypoid tumors of the large intestine. The frequencies were significantly different and the frequency gap amounted to 60%. However, 18 of 20 (90%) gastric adenocarcinomas were nonpolypoid in shape, whereas two (10%) were polypoid. DNA aneuploidy was found in 50% of the gastric adenocarcinomas and 56% of the nonpolypoid gastric adenocarcinomas. This value did not differ from the values reported previously for the submucosally invasive and advanced crater-shaped intestinal type adenocarcinomas of the stomach. Biologic characteristics of adenocarcinomas of the large intestine can be compared with those of intestinal type adenocarcinomas of the stomach, because intestinal type gastric adenocarcinoma is surrounded mostly by intestinalized mucosa and considered to arise from the epithelium under induction or progression of intestinal differentiation. Therefore, we inferred that the frequency gap in DNA aneuploidy between the crater-shaped and polypoid tumors of the large intestine implies that in the large intestine approximately 60% of the crater-shaped invasive carcinomas develop from the small nonpolypoid carcinomas.

Adenocarcinoma↗

PubMedDate not supplied

[The functional disorders of the large intestine (a lecture)].

Current ideas on the etiology and pathogenesis of functional disorders of the large intestine are discussed. Their classification, clinical picture, principles of diagnosis and differential diagnosis are outlined with emphasis of the most spread functional diseases of the large intestine: functional (common) obstipation, irritation of the large intestine pruritus ani, insufficiency of anal sphincters, proctalgia. Special attention is paid to treatment (diet, drugs, physiotherapy, spa).

Colonic Diseases, Functional↗

PubMed1987

[Neural regulation of the secretion of the small and large intestines].

The small bowel and the colon are supplied by a dense network of nerves. Nervous control of secretion is influenced by peripheral and central nerves. The small and large intestine are tonically inhibited by the enteric nervous system, in particular by the submucous plexus, to maximally absorb fluid and electrolytes. Choleratoxin induced intestinal secretion may be suppressed by central opiate receptors, and central gamma-aminobutyric acid receptors may inhibit intestinal absorption. Besides the classical neurotransmitters acetylcholine and noradrenalin, which stimulate and inhibit, respectively, secretion, a large number of regulatory peptides and other substances which mainly act as cotransmitters and neuromodulators affect mucosal transport in the small and large intestine. Secretion induced by nerves appears to play a major role in diabetic and infectious diarrhea. The nervous control of secretion in the small and large intestine is an interesting area of current research in intestinal transport. So far already, the results shed new light in a better understanding of intestinal pathophysiology, and they point towards new therapeutic modalities in diarrhea and constipation.

Animals↗

PubMed2000

Systemically derived large intestinal CD4(+) Th2 cells play a central role in STAT6-mediated allergic diarrhea.

Systemically primed BALB/c mice developed severe diarrhea after repeated oral administration of ovalbumin (OVA). Histological analysis demonstrated that dramatic infiltration of eosinophils and mast cells occurred in the large intestine but not in the small intestine of mice with diarrhea. Interestingly, CD4(+) alphabeta T cells of the large intestine secreted IL-4 and IL-13 at high levels. Identically treated STAT6 gene-disrupted mice failed to develop OVA-induced diarrhea. Further, treatment of BALB/c mice with monoclonal anti-IL-4 antibody prevented the development of allergic diarrhea. An adoptive transfer study showed that systemically primed splenic CD4(+) T cells were preferentially recruited into the large intestine upon exposure to oral OVA. These results strongly suggest that systemically derived CD4(+) alphabeta T cells of the large intestine play a critical role in the onset of Th2-mediated intestinal allergic disorders via STAT6 signal transduction.

Adoptive Transfer↗

PubMed2005

Transport of bacteria across and along the large intestinal lumen of guinea pigs.

Flow cytometry was used to observe the transport of fluorescently labelled viable bacteria in the large intestinal lumen of guinea pigs after the injection of the bacteria into the proximal colon. Bacteria were transported along the radial and longitudinal axes of the intestine and were separated from dietary residue, accumulated, and then transported back to the caecum. These observations, together with the heterogeneous distribution of bacterial species and chemical composition across and along the large intestine, suggest that there are several different microenvironments within the intestinal lumen between which bacteria and/or dietary residues move. The existence of different microenvironments within the intestinal lumen is consistent with poor mixing of the digesta within the large intestine of pigs and chickens.

Animals↗

PubMed1985

The histopathology of bleeding from polyps and carcinomas of the large intestine.

Carcinomas, adenomas and nonneoplastic polyps of the large intestine were examined histopathologically for evidence of recent and old hemorrhage. Three percent of the carcinomas lacked evidence of hemorrhage, as did 7% of the adenomas. Fifty percent of hyperplastic polyps were negative for hemorrhage, but 23% had considerable hemorrhage or hemosiderin. These findings may have a bearing on the results in fecal occult blood testing for the detection of cancer. Carcinomas bleed mainly from erosions on their luminal surface, but adenomas rarely show this feature. Twisting and bending of polyps, leading to fracture of fronds, and vascular obstruction, with passive congestion and stromal hemorrhage, appear to be the main sources of bleeding in polyps. Adenomas on the left side of the large intestine showed greater evidence of bleeding than did lesions on the right, but carcinomas did not show this relationship. Factors correlated with more severe hemorrhage were size, pedunculation, and villous growth of adenomas; for carcinomas, they were size, lack of mucin content, and lower differentiation. The age and sex of the patient and the extent of spread of carcinomas did not correlate with hemorrhage.

Adenoma↗