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Contractile and non-contractile proteins and nucleic acids in the stomach, whole jejunum and seromuscular layers of the duodenum, jejunum, ileum and large intestine in response to chronic ethanol feeding.

Rats were fed a nutritionally adequate liquid diet containing 35% of the total calories as ethanol (treated), or identical amounts of the same diet in which ethanol was replaced with isocaloric glucose (controls). At 6 weeks, rats were killed and the stomach (cardiac region), duodenum, jejunum, ileum and the large intestine (combined colon and rectum) were dissected. Seromuscular layers were prepared from the duodenum, jejunum, ileum and the large intestine. After 6 weeks of chronic ethanol feeding the wet weights of the stomach and whole jejunum were reduced by 31%. The wet weights of the duodenum, jejunum and distal ileum seromuscular layers were reduced by 19-25%. The wet weight of the large intestine seromuscular layer was unaltered. The total amounts of contractile and non-contractile protein in the small intestinal seromuscular layers were reduced by 16-52%. In jejunal serosa, the RNA contents were reduced by 29%, but total RNA contents in the serosa of the ileum and duodenum were not significantly altered. Total DNA content was reduced in jejunal and ileal serosal layers by 22 and 33%, respectively, but remained unchanged in duodenal serosa. In the stomach, total contractile and non-contractile protein was reduced by 26-52% and similarly total RNA and DNA were also decreased by 47 and 34%, respectively. Chronic ethanol feeding had no apparent effect on either contractile or non-contractile total protein, total RNA or DNA contents in colonic and rectal serosa. In the combined mucosal and seromuscular layers of the jejunum, much greater effects due to ethanol feeding were observed when compared with the jejunal seromuscular layer alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcoholism↗

[Delay phenomenon of the jejunum. Studies of nutritional blood supply and oxygen supply of the jejunum of the rabbit].

INTRODUCTION: Delay procedure has been shown to effectively improve microvascular perfusion in skin flaps. In analogy to skin, we have analyzed the effect of delay on regional blood flow and surface tissue PO2 of a proximal segment of the jejunum. METHODS: Under nembutal anesthesia (30 mg/kg BW) and mechanical ventilation a total of 15 rabbits were laparotomized. Regional blood flow of the jejunum was estimated using radioactive-labeled microspheres, and tissue PO2 was assessed by means of a platinum-multiwire surface electrode. In order to induce acute ischemia three consecutive jejunal arteries were ligated, and the proximal marginal vascular arch was temporarily occluded by a microvascular clip. Delay procedure was induced by 1) ligation of the jejunal arteries, 2) in situ-maintenance of the jejunal segment for two weeks followed by 3) relaparotomy and occlusion of the proximal marginal arch (n = 8). Regional blood flow of the jejunum and tissue PO2 were also assessed in sham-operated animals (n = 7). RESULTS: After acute ischemia regional blood flow (0.27 (0.05) ml x min-1 x g-1, mean (SEM)) and surface tissue PO2 (39 (3) mmHg) of the jejunal segment were found significantly (p < 0.05) reduced as compared to baseline (0.82 (0.12) ml x min-1 x g-1 and 66 (1) mmHg) and sham-operated animals (0.69 (0.12) ml x min-1 x g-1 and 62 (5) mmHg), respectively. In contrast, delay of the jejunal segment resulted in almost complete preservation of regional blood flow (0.56 (0.04) ml x min-1 x g-1) and surface tissue PO2 (65 (1) mmHg). CONCLUSION: We therefore like to propose that the jejunal delay phenomenon may be clinically used to reduce ischemic complications in jejunal transposition for esophagoplasty.

Animals↗

Discrepancies between effects of recombinant human growth hormone on absorption and secretion of water and electrolytes on the human jejunum compared to results reported on rat jejunum.

Previous studies in rats showed that the administration of recombinant human growth hormone markedly increased intestinal absorption of electrolytes and water and suggested that growth hormone would be a useful antidiarrheal agent. We therefore examined the effect of recombinant human growth hormone on the human jejunum in vivo, using a triple lumen nonabsorbable marker technique. Healthy subjects were studied on two different test days, one as a control and a second where recombinant human growth hormone was injected subcutaneously in a dose of 100 microg/kg. With this dose we achieved equal or higher growth hormone serum levels than in previous rat studies. However the administration of recombinant human growth hormone did not stimulate absorption or inhibit secretion of water and electrolytes in the human jejunum in vivo. We believe that the discrepancy between humans and rats is most likely due to the species difference rather than to differences in methods that were used. Therefore recombinant human growth hormone cannot be considered a useful proabsorptive antidiarrheal agent in humans.

Adult↗

[Submicroscopic changes in the jejunum in ectopic sites. A scanning and transmission electron microscopy study following free, microvascular jejunum transfer].

Biopsies of the jejunal epithelium were analysed by scanning and transmission electron microscopy of specimens taken from patients at least 1 year after reconstruction of defects from resection of oro-hypopharyngeal cancer by free microvascular anastomized jejunum graft. The villi were compressed and flattened, their surface uneven due to calibre changes of columnar cells. The microvilli were rarefied and grossly altered. In the subapical area there was a distinct enhancement of desmosomal connections. Paneth cells and endocrine cells were unaltered. Autonomic nerves were intact, though the muscularis mucosa seemed to be denervated.

Biopsy↗

Expression of the common acute lymphoblastic leukaemia antigen (CALLA gp100) in the brush border of normal jejunum and jejunum of patients with coeliac disease.

Expression of the gp100 common acute lymphoblastic leukaemia antigen (CALLA) was studied in the mucosa of the gut by means of indirect immunofluorescence on cryostat tissue sections with a panel of eight monoclonal antibodies to common acute lymphoblastic leukaemia antigen (anti-CALLA antibodies) and two antibodies to non-CALLA leukaemic antigens. Expression of CALLA was absent from normal stomach epithelium, adult and fetal colonic epithelium of normal histology, and colonic epithelium from patients with Crohn's disease or ulcerative colitis. By contrast, all eight anti-CALLA antibodies gave a characteristic reaction in normal adult and fetal small bowel mucosa, with specific localisation to the entire brush border of jejunal epithelium. Whereas seven of these antibodies reacted both with normal jejunal epithelium and with the damaged epithelium of patients with coeliac disease, antibody RFAL-2 reacted strongly only with histologically normal small bowel but more weakly in patients with coeliac disease to a degree related to the amount of histological abnormality. Expression of the moeity like CALLA identified with RFAL-2 was strongest in crypt epithelium and proportionally diminished along the villi according to the amount of histological damage in coeliac disease, being essentially absent in patients with "subtotal villous atrophy."

Adult↗

Segmental heterogeneity of cellular and paracellular calcium transport across the rat duodenum and jejunum.

Concentration- and voltage-dependent 45Ca transport was measured across the rat duodenum and jejunum. Mucosa-to-serosa calcium transport across the short-circuited tissue exhibits a saturable component, whereas serosa-to-mucosa calcium flux in both segments is linear to the calcium concentration between 0.125 mmol/L and 10 mmol/L. Calcium is absorbed in the duodenum at concentrations between 0.125 mmol/L and 2.5 mmol/L but is secreted in the jejunum at all concentrations. The simultaneously measured paracellular marker [3H]mannitol at all calcium concentrations is secreted in both segments. The study across clamped preparations shows that (a) only mucosa-to-serosa calcium flux has a voltage-independent cellular component; (b) serosa-to-mucosa calcium flux is totally voltage dependent, i.e., diffusive and probably restricted to the paracellular pathway; (c) diffusive calcium flux in the duodeum is equal in both directions; and (d) diffusive serosa-to-mucosa flux in the jejunum is higher than the corresponding flux in the opposite direction, suggesting that calcium passively is secreted in the jejunum as the consequence of a preference of the paracellular serosa-to-mucosa calcium movement caused by "anomalous solvent drag effect." 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3] stimulates serosa-to-mucosa and more pronounced mucosa-to-serosa calcium flux and increases calcium absorption in the duodenum and abolishes calcium secretion in the jejunum. 1,25(OH)2D3 stimulates cellular mucosa-to-serosa calcium flux in the duodenum only but has no effect on cellular calcium in the jejunum. However, the vitamin increases bidirectional diffusive calcium fluxes across both segments. Tissue resistance is decreased and the flux of the paracellular marker mannitol in both directions is increased, suggesting that 1,25(OH)2D3 stimulates diffusive calcium flux across both segments by increasing the paracellular permeability. Dexamethasone inhibits cellular mucosa-to-serosa calcium flux and abolishes calcium absorption in the duodenum only but has no effect on cellular calcium flux in the jejunum. The glucosteroid has no influence on diffusive calcium flux in the duodenum but increases voltage-dependent bidirectional calcium flux across the jejunum. Simultaneously, the flux of the paracellular probe mannitol in both directions across the jejunum is increased, whereas mannitol flux in the duodenum is unresponsive to dexamethasone.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Absorption of electrolytes and water by the jejunum and colon in milk-fed lambs.

Net absorption of electrolytes (Na, Cl, K, Ca) and water from ligated loops was studied at various intestinal sites in milk-fed lambs. The unidirectional fluxes of Na across the intestinal mucosa were also investigated using 22Na. Net Na and water absorption in the mid-jejunum were about two-fold higher than in the proximal and distal jejunum and the colon descendens. With the exception of the proximal jejunum, Na and Cl absorption did not differ significantly. The unidirectional Na fluxes in both directions were much higher in the proximal and mid-jejunum than in the distal jejunum and colon descendens. K was also absorbed most efficiently from the mid-jejunum. In the colon descendens mean net K absorption was about zero. Ca absorption in the upper and mid-jejunum exceeded that of the distal jejunum and colon descendens, where the values were close to zero. The results show that in the whole jejunum of young milk-fed lambs net absorptive fluxes of Na, Cl, K, Ca and water occur, whereas the colon descendens appears to play a role only in Na, Cl and water absorption.

Animals↗

Mucosal function in rat jejunum and ileum is altered by induction of colitis.

Many studies dealing with trinitrobenzene sulfonic acid (TNBS) colitis in rats have been carried out referring only to the colon. In humans, ulcerative colitis (UC) can extend a variable distance into the terminal ileum in a phenomenon known as backwash ileitis (BWI). The aim of this study was therefore to examine the effect of TNBS-induced colitis on different aspects of the rat ileum and jejunum. We hypothesized that TNBS administration would lead to a systemic influence on the small intestine. Rats were induced colitis by administration of 0.25 ml of 2,4,6-trinitrobenzene sulfonic acid and 72 h after colitis induction animals were sacrificed. Segments were taken of the colon, ileum and jejunum. In addition to mucin mRNA expression, morphological changes were observed in the jejunum and ileum. We examined the mRNA expression and biochemical activity of brush border enzyme, sucrase iso-maltase and aminopeptidase, in all three segments. The villous surface area of colitis-induced rats was smaller in jejunum and ileum compared to control. In the jejunum of TNBS-induced rats, goblet-cell volume increased and their density decreased. The relative amount of MUC2 mRNA decreased in the jejunum, ileum and colon of colitis rat. However, MUC3 mRNA expression increased in the ileum and colon of these rats. Sucrase isomaltase expression and activity decreased in the ileum of TNBS-induced rats, while aminopeptidase activity was lower in the jejunum. These observations suggest that intrarectal administration of TNBS to rats influences not only their colon and terminal ileum, but also the proximal ileum and jejunum. Involvement of the ileum and jejunum in TNBS-induced colitis may be related to the systemic reaction of the immune system and mucosa to colitis.

Aminopeptidases↗

Comparison of the intestinal secretory response to 5-hydroxytryptamine in the rat jejunum and ileum in-vitro.

A secretory response to 5-hydroxytryptamine (5-HT) is observed throughout the intestinal tract; this investigation has compared the nature of this response in the jejunum and ileum of the rat in-vitro. Different basal electrical activity was observed for jejunal and ileal sheets of rat small intestine. In both intact and stripped preparations the basal short-circuit current (SCC) was greater and the tissue resistance lower in the jejunum than in the ileum. 5-HT caused concentration-dependent increases in SCC in intact and stripped preparations of both regions. EC50 values were similar in the jejunum and ileum, stripped sheets from both regions showing greater sensitivity. In the ileum the maximum increase in SCC induced by 5-HT was similar in intact and stripped sheets, but in the jejunum the response was greater in intact preparations. The jejunal response to 5-HT was reduced in the absence of bicarbonate but unaffected by lack of chloride, whereas the ileal response was inhibited by removal of chloride but unaltered in bicarbonate-free conditions. In intact sheets the tetrodotoxin-sensitive neural component was greater in the jejunum. In stripped sheets a neural component could still be detected in the ileum, but not in the jejunum. There are, therefore, fundamental differences in the way in which the jejunum and ileum respond to 5-HT stimulation--the jejunal response is primarily a result of stimulation of bicarbonate secretion whereas chloride secretion predominates in the ileum. The myenteric plexus appears to play a more prominent role in the jejunum; in the ileum other neural elements also contribute to the response.

Animals↗

Abnormal epithelial transport in cystic fibrosis jejunum.

Abnormal epithelial electrolyte transport has been identified in a range of cystic fibrosis (CF) organs and appears to account for the various clinical manifestations of the disease. The aim of this study was to further define the Cl- secretion defect in CF jejunum. Excised jejunum was obtained from 11 CF patients and 12 controls. Transport studies were performed on stripped epithelium in vitro under short-circuited conditions in Ussing Chambers. 3-Isobutyl-1-methylxanthine (IBMX) (300 microM) significantly increased Cl- secretion in control (-2.3 +/- 0.6 to -3.3 +/- 0.7 mueq.cm-2.h-1; P less than 0.01, paired t test; n = 5 subjects) but not in CF jejunum (-0.5 +/- 0.3 to -0.1 +/- 0.4; n = 4). However in contrast to control jejunum, net Na+ absorption in CF jejunum was higher in the IBMX (1.3 +/- 0.5 mueq.cm-2.h-1) compared with basal periods (0.6 +/- 0.3; P less than 0.05, paired t test). IBMX stimulation of tissue adenosine 3',5'-cyclic monophosphate (cAMP) was similar in both control and CF jejunum. A range of secretagogues known to induce secretion in mammalian intestine, including dibutyryl cAMP (DBcAMP), DBcGMP, Ca2+ ionophore A23187, and the protein kinase C activator 4 beta-phorbol 12,13-dibutyrate, failed to induce secretion in CF jejunum. In conclusion, CF jejunum failed to exhibit Cl- secretion and also demonstrated abnormalities of Na+ absorption. These results support the view that the defect lies at a site distal to the intracellular messengers. Moreover, these abnormalities of intestinal electrolyte transport may account for some of the gastrointestinal manifestations of the disease such as meconium ileus and distal intestinal obstruction syndrome.

1-Methyl-3-isobutylxanthine↗