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PubMed1980

Effect of cecum and appendix on 7 alpha-dehydroxylation and 7 beta-epimerization of chenodeoxycholic acid in the rabbit.

The effect of surgical removal of cecum and appendix on bile acid metabolism was studied in the rabbit. Bile acid composition of bile and intestinal contents were analyzed by gas-liquid chromatography and individual bile acids were further identified by mass spectrometry. In normal, intact rabbits (group I), the biliary bile acids consisted largely of deoxycholic acid (DA) 95.3 +/- 1.0 (mean +/- SE) %; cholic acid (CA) 2.3 +/- 1.1% and lithocholic acid (LA) 1.0 +/- 0.3% were also detected. Removal of cecum and appendix (group II) produced significant changes in biliary bile acid composition: DA fell to 58.3 +/- 31.8%, CA rose to 37.7 +/- 10.4%, and LA was barely detectable (0.3 +/- 0.1%). Administration of chenodeoxycholic acid (CDA), 125 mg/day, produced severe hepatotoxicity, reduced food intake, and produced weight loss (group III). Biliary LA rose to 15.0 +/- 1.3%, while DA was 61.3 +/- 14.0% and CDA 21.8 +/- 14.6% of total biliary bile acids. Feeding CDA to animals without cecum and appendix (group IV) resulted in a slight increase of LA (3.2 +/- 2.2%) compared to group III, and appreciable amounts of ursodeoxycholic acid (UDA) 32.0 +/- 9.8% and of 7-ketolithocholic acid (7-KLA) 3.0 +/- 0.6% appeared in bile. The animals of group IV exhibited no hepatotoxicity and ate and gained weight normally. These results indicate that the microbial population of cecum and appendix is active in 7alpha-dehydroxylation of primary bile acids and that removal of these organs results in an increased formation of UDA by an unknown mechanism.-Yahiro, K., T. Setoguchi, and T. Katsuki. Effect of cecum and appendix on 7alpha-dehydroxylation and 7beta-epimerization of chenodeoxycholic acid in the rabbit.

Animals↗
PubMed1995

Detection of Clostridium difficile toxins from the small intestine and cecum of rabbits with naturally acquired enterotoxemia.

Four specific-pathogen-free rabbits with anorexia died peracutely; decreased fecal output, nasal exudate, and labored breathing were the only other clinical abnormalities observed in two of the rabbits before death. The animals, three juveniles and one adult, were on a standard polyclonal antibody production regimen and had received immunizations approximately 2 weeks before presentation. External examination revealed distended abdomen and perineal fecal staining. At necropsy the small intestine was distended with fluid, and the cecum was distended with chyme. The small intestines and cecum had marked serosal hyperemia. Anaerobic bacterial culture techniques were used to isolate Clostridium difficile from the small intestine (3/4) and cecum (2/4). In all cases C. difficile toxin B was detected at high titers (10(2) to > 10(5)) in the small intestine by cytotoxicity assay with HeLa 229 cell culture. In two of the four rabbits C. difficile was isolated, and cytotoxin titers were detected at 10(1) and 10(4) in the cecum of affected rabbits. Toxin B was neutralized with C. sordellii antiserum but not C. spiroforme antiserum. In addition, toxin A was detected in each of the cytotoxin B-positive samples by a commercial toxin A enzyme immunosorbent assay. In vitro production of toxins A and B was detected from each culture isolate after incubation in chopped meat broth. These cases are noteworthy because spontaneous (nonantibiotic-associated) C. difficile enterotoxemia has not been previously reported in rabbits. Also the toxins of clostridial organisms are usually documented in the cecum, not the small intestine, of rabbits.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Adenocarcinoma of the cecum with Crohn's-like features in baboons.

During the past 9.5 years, 51 baboons dying as a result of chronic diarrhea and poor health and having a chronic inflammatory process of the cecum (i.e. typhlitis) were recorded. The cecum was turgid, irregularly thickened the lumen reduced and the mesenteric lymph nodes enlarged. Of the 45 baboons with well preserved histologic material, 24 had shallow ulcerations and/or focal mucosal inflammation, 3 had crypt abcesses, 3 had mucosal fissures,l aphtoid ulcerations, and 1 pseudopyloric metaplasia (ulcer associated cell lineage-UACL-). The submucosa in all 45 animals was thick due to fibrosis, 35 had focal chronic inflammation with lymphoid aggregates, 12 submucosal abcesses, 6 epithelioid cell granulomas, 5 fissures reaching the submucosa, 3 neural hyperplasia of the myenteric plexus, and 2 lymphangiectasia. Focal chronic transmural inflammation with lymphoid aggregates was recorded in 44 animals. In addition, 2 animals showed deep fissure tracts. Ten of the 45 animals had in addition a cecal adenocarcinoma; one was overlayed by a villous adenoma with high grade dysplasia. Liver metastasis was found in another animal. The present study indicated that a) baboons may develop transmural chronic focal inflammation in the proximal colon (cecum), b) the inflammation in baboons closely mimic Crohn's disease of the cecum in humans c) adenocarcinomas in baboons with Crohn's-like inflammatory changes may originate in an adenomatous growth, and d) cecal adenocarcinomas in baboons with Crohn's-like inflammatory changes of the cecum, are able to metastasize.

Adenocarcinoma↗
PubMed1989

Absorption by the cecum of wild birds: is there interspecific variation.

The major functions proposed for the avian cecum--energy balance and osmoregulation--involve absorption of material from the cecum, yet little is known of these absorptive processes in wild birds. The magnitude of transport of compounds from the ceca depends on the concentrations of compounds in the ceca, the presence of transport pathways for those compounds, and the size of the reabsorptive surface. Interspecific variation in size of avian ceca is well documented, but the other two determinants of absorption are much less well studied. All ceca examined contained acetic, propionic, and butyric acid; water content varies from less than 70 to greater than 90%. Most other constituents have been quantified in just one or two species. A model for cecal transport, derived from studies of mammalian ceca but consistent with observations on birds, is described. A luminal (mucosal) Na+/H+ exchanger couples the absorption of Na+ to that of volatile fatty acids, which are absorbed in their uncharged (protonated) form; these two compounds are thereby mutually stimulatory in their absorption. The cecum also absorbs water, sodium, carbon dioxide, and probably some nitrogenous compounds (e.g., ammonia). Too few data exist to analyze interspecific variation in cecal transport in birds. However, variations in the following characteristics do exist: cecal contents, cecal absorptive surface area, transport characteristics of other regions of avian intestine (e.g., rectum), cecal transport among mammalian species, and histology of avian ceca. Studies of the physiological consequences of these variation should yield insight into the function and contributions of the avian cecum.

Absorption↗
PubMed1989

Interspecific variation in sugar and amino acid transport by the avian cecum.

Previous studies of cecal sugar and amino acid transport in the domestic chicken led to a widely held generalization that the avian cecum is unimportant as a site of nutrient transport. In fact, we found that the uptake capacity of the cecum for hexose sugars and amino acids is substantial in some species of birds. Cecal transport of glucose was measurable in all five study species (Canada goose, sage grouse, domestic chicken, red-necked phalarope, and rock dove), approached or exceeded intestinal levels in the grouse and phalarope, and accounted for between 0.1% (rock dove) and 49% (sage grouse) of the whole gut's integrated uptake capacity. Proline uptake averaged higher in the proximal portion of the cecum than in any region of the small intestine for all species but the goose. The ceca contributed between 2% (rock dove) and 25% (sage grouse) of the gut's integrated uptake capacity for proline. Similar ranges were found for fructose, lysine, leucine, and aspartate. Future studies should be undertaken to search for phylogenetic and ecological correlates of the interspecific variation in cecal transport and to determine how nutrient transport integrates with other functions of the avian cecum.

Amino Acids↗
PubMed1985

Quinacrine-induced dilation of the rat cecum and degeneration of large granular vesicle-containing neurons in the myenteric plexus.

Intraperitoneal injection of quinacrine (100 mg/kg) into rats causes marked dilation of the cecum about one week after the injection, but the jejunum remains its normal size. The morphological changes induced in the myenteric plexus and the longitudinal and circular muscle layers of both the cecum and the jejunum have been examined by fluorescence and electron microscopy 1.5 h to 2 weeks after the injection. In the cecum, 1.5 h after the injection, the granular fluorescence of quinacrine was apparent in many ganglion cells of the myenteric plexus and in the nerve fibers in the muscle layers. In connection with the granular fluorescence, numerous lysosomal dense bodies appeared in ganglion cells and axons, and subsequently the degeneration of the neurons was observed at ultrastructural level. The lysosomal dense bodies often contained many large granular vesicles of 95-140 nm in diameter. The number of lysosomal dense bodies in the axons was greatest 3-7 days after the injection. Although the axon type sensitive to quinacrine could not be specified, axons containing many large granular vesicles were the predominate type. Fibrosis in the outer longitudinal muscle layer was another characteristic resulting from quinacrine administration. Proliferation of the rough-surfaced endoplasmic reticulum and of the Golgi complex and a concomitant decrease in the number of myofilaments became evident in many smooth muscle cells 3-7 days after the injection; the intercellular spaces became enlarged 7 days after quinacrine administration. These changes and the dilation of the cecum showed considerable recovery 2 weeks after the injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1979

Anatomy of the cecum of the dwarf hamster (phodopus sungorus).

The cecal anatomy of the dwarf hamster, Phodopus sungorus, was investigated macroscopically and at the light, transmission electron microscopic and scanning electron microscopic levels. In addition, the arterial supply to the cecum and connecting mesenteries were elucidated. The cecum is divisible into an ampulla ceci and a corpus ceci. In the former, the differentiation of the ileocecal orifice and circumventing fold is described. Scanning electron microscopically, the surface topography of the cecum appears as ring-walled elevations with a central depression and looped configurations, which correlate light microscopically to a "rolling-hills" type mucosa with wide-opened crypts. This type of mucosa is set in contrast to the classically described large intestinal mucosa in man and some other mammals. The present observations are compared with descriptions made on the cecum of the common field vole, Microtus agrestis, also a myomorph but belonging to another subfamily.

Animals↗
PubMed1978

Anatomy of the rabbit cecum.

The anatomy of the rabbit cecum was investigated using macroscopic dissections, vascular injections, dried total specimens, light microscopy, and scanning and electron microscopy. The morphology of the three portions of the cecum (ampulla coli, corpus ceci and appendix vermiformis) is described. For comparison, the proximal colon, ileum and sacculus rotundus were also investigated. The thickness of the different layers of the intestinal wall of each area was measured. The arterial supply and mesenteries of the cecum were also studied. The rabbit cecum represents structurally a highly developed organ.

Animals↗
PubMed1986

Adaptation of electrolyte transport in rat large intestine after proximal resection. I. Cecum and colon after 60% jejunoilectomy.

Electrolyte transport was studied in rat cecum and colon adapting to 60% resection of the small intestine. Four weeks after surgery, the absorbing gross surface area, dry and wet weight, net absorption in vivo of sodium, chloride and volume, net potassium secretion, transmural electrical potential difference and mucosal Na-K-ATPase specific activity were determined. In the cecum, all tissue mass parameters were increased compared to sham-operated controls. Net transport was stimulated per organ but not per unit mass, and potential difference and Na-K-ATPase remained unaffected. In the colon, surface area and wet weight increased slightly while dry weight and electrolyte transport were not influenced. Thus, by enlargement without a change in cell function, the cecum but not the colon contributes to electrolyte homoeostasis after 60% jejunoilectomy in the rat. Na-K-ATPase specific activity and electrical potential difference were higher in the colon than the cecum, suggesting segmental heterogeneity of the larger bowel with respect to Na-K-ATPase-linked active sodium absorption.

Adenosine Triphosphatases↗
PubMed1992

Hormonal and pharmacologic regulation of sodium absorption in rabbit cecum in vitro.

The rabbit cecum is a moderately tight epithelium with amiloride-resistant but phenamil-sensitive electrogenic Na absorption. We performed flux and electrical studies under short-circuit conditions in vitro to further characterize the mechanisms of ion transport in cecum in normal and animals pretreated with methylprednisolone (MP) and deoxycorticosterone acetate (DOCA). MP treatment increased Na absorption and decreased tissue conductance. In contrast, DOCA increased Isc but did not significantly alter Na or Cl fluxes. Amiloride analogs with primary specificity for Na channel and Na/H exchanger both inhibited Isc and Na absorption. Ethacrynic acid, but not bumetanide, inhibited Isc. Nystatin and amphotericin B increased Isc. We conclude that: (1) Steroids have a differential effect on cecal ion transport; methylprednisolone increases Na absorption, but DOCA does not. (2) The response to amiloride analogs is different from other electrogenic transport systems, suggesting a distinct mechanism of Na transport in cecum. (3) The effect of ethacrynic acid was unexpected, suggesting an inhibitory response on an alternate transport system. (4) The effects of polyene antibiotics are similar to those found in other tight epithelia. Electrogenic Na absorption in rabbit cecum represents a distinct transport system, significantly different from Na absorptive mechanisms in other segments of the gut.

Amiloride↗
PubMed1988

Effect of cholecystectomy on mouth-to-cecum transit of a liquid meal.

Mouth-to-cecum transit and serum bile acid profile after ingestion of a lactulose-labeled liquid meal (440 kcal) were measured in eight patients with gallstones and a radiologically functioning gallbladder before and three to five months after cholecystectomy and in 15 controls. In the patients mouth-to-cecum transit was longer after the operation, 87.5 +/- 18.5 (mean +/- SEM) min vs 57.5 +/- 9.7 min (P less than 0.05). Mouth-to-cecum transit times before and after the operation were not different from controls (58.0 +/- 6.7 min). Serum bile acid AUCs were similar (P = NS) in patients and controls, while total bile acid and cholylglycine fasting concentrations were higher after cholecystectomy (P less than 0.05 and P less than 0.01 respectively). Cholecystectomy prolongs mouth-to-cecum transit of a liquid meal.

Adult↗
PubMed1990

Morphometry of the galliform cecum: a comparison between Gambel's quail and the domestic fowl.

Tissues from the proximal, middle, and distal regions of the ceca of Gambel's quail and domestic fowl were examined by scanning and transmission electron microscopy. Cellular and subcellular structures, including epithelial cell height, mitochondrial volume fraction, microvillous surface area, proportion of goblet cells, and junctional complex characteristics, were quantified by a variety of stereologic procedures and other measurement techniques. The mucosal surface of quail cecum shows a much more highly developed pattern of villous ridges and flat areas than that of fowl cecum. The fowl has significantly greater cell heights than the quail in all cecal regions. The mitochondrial volume fraction does not differ significantly with species or region, but mitochondria are concentrated on the apical side of the nucleus. In both species, the proximal cecal region has the greatest microvillous surface area. All 3 components of junctional complexes, including zonula occludens, zonula adhaerens, and macula adhaerens, are quantified. When all factors are considered, the quail cecum appears to have morphological characteristics consistent with a greater potential capacity for absorption than the fowl cecum.

Animals↗
PubMed1984

Isolated ischemic necrosis of the cecum in patients with chronic heart disease.

Isolated ischemic necrosis of the cecum is an infrequently described entity. We report three cases seen at our institution within a three-year period. All three patients had been hospitalized for congestive heart failure in the past, but none was in failure at the time of the most recent hospitalization. All three patients presented with clinical and laboratory findings consistent with acute appendicitis. At surgery the cecum was ischemic in each case, while the appendix and the remainder of the intestine appeared normal. There was no evidence of major vascular occlusion or embolization at the time of original operation. We propose that the cecum, like the splenic flexure, is a "watershed area," with poor blood supply relative to that of the adjacent intestine. While cecal ischemia has been described in association with a variety of clinical entities, we propose a newly recognized association with poor myocardial function. In such patients, isolated ischemic necrosis of the cecum should be considered in the differential diagnosis of right lower quadrant pain.

Aged↗
PubMed2007

Cloning and identification of novel cellulase genes from uncultured microorganisms in rabbit cecum and characterization of the expressed cellulases.

A metagenomic cosmid library was prepared in Escherichia coli from DNA extracted from the contents of rabbit cecum and screened for cellulase activities. Eleven independent clones expressing cellulase activities (four endo-beta-1,4-glucanases and seven beta-glucosidases) were isolated. Subcloning and sequencing analysis of these clones identified 11 cellulase genes; the encoded products of which shared less than 50% identities and 70% similarities to cellulases in the databases. All four endo-beta-1,4-glucanases and all seven beta-glucosidases, respectively, belonged to glycosyl hydrolase family 5 (GHF 5) and family 3 (GHF 3) and formed two separate branches in the phylogenetic tree. Ten of the 11 cloned cellulases exhibited highest activities at pH 5.5 approximately 7.0 and 40 approximately 55 degrees C, a condition similar to that in the rabbit cecum. All the four endo-beta-1,4-glucanases could hydrolyze a wide range of beta-1,4-, beta-1,4/beta-1,3- or beta-1,3/beta-1,6-linked polysaccharides. One endo-beta-1, 4-glucanase gene, umcel5G, was overexpressed in E. coli, and the purified recombinant enzyme was characterized in detail. The enzymes cloned in this work represented at least some of the cellulases operating efficiently in the rabbit cecum. This work provides the first snapshot on the cellulases produced by bacteria in rabbit cecum.

Animals↗
PubMed1987

Ion transport in human cecum, transverse colon, and sigmoid colon in vitro. Baseline and response to electrical stimulation of intrinsic nerves.

In a flux chamber study of ion transport in human colon, we compared baseline rates with those measured during electrical stimulation of intrinsic nerves. In baseline studies, sodium was absorbed throughout, but maximally in transverse colon. In cecum, sodium absorption accounted for the short circuit current and chloride was not absorbed. Chloride was absorbed in transverse and sigmoid colon, however. Residual current was minimal in cecum and transverse colon, but increased in sigmoid colon. Neural stimulation caused chloride secretion in cecum, reduced chloride absorption in sigmoid colon, but caused no change in transverse colon; sodium absorption decreased in cecum. A neurotransmitter of unknown identity affects baseline short circuit current in sigmoid colon. Half of the increase in short circuit caused by neural stimulation in sigmoid colon is mediated by muscarinic receptors. The identity of the other transmitter(s) is not known. It is not substance P or histamine. The three divisions of the colon differ in relative rates of baseline ion transport and in their transport responses to intrinsic nerve stimulation.

Cecum↗
PubMed2005

The pattern of neural crest advance in the cecum and colon.

Neural crest cells leave the hindbrain, enter the gut mesenchyme at the pharynx, and migrate as strands of cells to the terminal bowel to form the enteric nervous system. We generated embryos containing fluorescent enteric neural crest-derived cells (ENCCs) by mating Wnt1-Cre mice with Rosa-floxed-YFP mice and investigated ENCC behavior in the intact gut of mouse embryos using time-lapse fluorescent microscopy. With respect to the entire gut, we have found that ENCCs in the cecum and proximal colon behave uniquely. ENCCs migrating caudally through either the ileum, or caudal colon, are gradually advancing populations of strands displaying largely unpredictable local trajectories. However, in the cecum, advancing ENCCs pause for approximately 12 h, and then display an invariable pattern of migration to distinct regions of the cecum and proximal colon. In addition, while most ENCCs migrating through other regions of the gut remain interconnected as strands; ENCCs initially migrating through the cecum and proximal colon fragment from the main population and advance as isolated single cells. These cells aggregate into groups isolated from the main network, and eventually extend strands themselves to reestablish a network in the mid-colon. As the advancing network of ENCCs reaches the terminal bowel, strands of sacral crest cells extend, and intersect with vagal crest to bridge the small space between. We found a relationship between ENCC number, interaction, and migratory behavior by utilizing endogenously isolated strands and by making cuts along the ENCC wavefront. Depending on the number of cells, the ENCCs aggregated, proliferated, and extended strands to advance the wavefront. Our results show that interactions between ENCCs are important for regulating behaviors necessary for their advancement.

Animals↗
PubMed2002

Effect of conjugated linoleic acid on the formation of spontaneous and PhIP-induced mutation in the colon and cecum of rats.

Conjugated linoleic acid (CLA), a mixture of positional and geometric isomers of linoleic acid, has been reported to inhibit chemically induced mammary and colon carcinogenesis in rodents. In a preliminary experiment, we found that CLA significantly reduced the induction of mutations by the dietary carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in the distal colon in male rats. Here, the chemopreventive properties of CLA were further evaluated by assessing its effect on PhIP-induced mutation and aberrant crypt foci (ACF) in both male and female rats. CLA (1%, w/w) was added to the diet (1) from weaning to 50-day-old, or (2) starting 1 week prior to exposure to PhIP. The 50-day-old Big Blue and F344 rats were then exposed to 100 ppm PhIP for 47 days. No sex differences were observed in mutagenic response to the various treatments in either the distal colon or cecum. The mutation frequency (MF) in the cecum and the distal colon from control animals is 4.3+/-1.3 and 5.3+/-1.4 x 10(-5), respectively showing no statistically significant difference. Administration of PhIP induced a four-fold increase in the MF in the cecum and a seven-fold increase in the distal colon compared to the corresponding controls. Supplementation of the diet with CLA lowered the PhIP-induced MF in the distal colon by 23% (P<0.03), but had no effect in the cecum. The PhIP-induced ACF, determined 9 weeks after the termination of treatment with PhIP, were 0.75 ACF/rat, with 1.7 aberrant crypts /ACF in the colon of male rats, all located in the distal colon. This induction was completely inhibited by the addition of CLA.

Animals↗
PubMed1989

Surgical diseases of the equine cecum.

Cecal impaction and cecal perforation, the two most common equine cecal diseases, are thought to develop after slowing or interruption of a single progressive motility pattern, which begins in a pacemaker area near the apex, occurs once every 3 minutes, and propels ingesta from the cecum to the right ventral colon. Rectal examination in horses with cecal impaction is the most useful technique to grade the severity of the condition. Medical treatment is undertaken if the impaction is judged to be mild to moderate. Surgical correction of cecal impaction in severe cases requires a ventral midline celiotomy, and exploration reveals a large ingesta-filled cecum and relatively empty large colon. Currently, the techniques of typhlotomy with manual evacuation of ingesta, combined with a complete bypass of the cecum by use of a jejunocolostomy, is the preferred method of surgical management. The use of a cecocolic anastomosis remains a viable alternative surgical procedure. Cecal perforation (CP), a uniformly fatal disease of horses, most often develops when the subtle signs of cecal impaction are missed or are masked by the administration of nonsteroidal antiinflammatory agents. CP can occur in mares around the time of foaling and, in this form, is not associated with cecal outflow dysfunction. Surgical management of cecocecal or cecocolic intussusception is required and involves resection of the diseased portion of cecum, either with extra- or intraluminal techniques. Both the side-to-side and end-to-side jejunocecal anastomoses are useful and successful techniques for bypass of simple or strangulating lesions of the ileum.

Animals↗