Increased frequency of activated T-cells in the Helicobacter pylori-infected antrum and duodenum

Helicobacter pylori colonize the human stomach and duodenum. The infection has been shown to induce a strong T-cell response in the stomach, whereas the response within the duodenum has been poorly characterized. Furthermore, it remains to be elucidated whether the T-cell response may contribute to ulcer formation in the host. In this study, the frequency of different T-cell subsets, their degree of activation and expression of co-stimulatory receptors in biopsies from the duodenum as well as the antrum were studied by immunohistochemistry and flow cytometry. It was also evaluated whether there are differences in the T-cell responses between duodenal ulcer patients and asymptomatic carriers that might explain why only 10-15% of the infected subjects develop duodenal ulcers. The frequencies of CD4+, CD8+ and CD45RO+, i.e. memory T-cells, were significantly increased in the antrum, and the number of CD25+ cells was considerably higher in both the antrum and duodenum of duodenal ulcer patients and asymptomatic carriers as compared to uninfected individuals. Interestingly, the levels of immunosuppressive CTLA-4+ cells were significantly higher in the duodenum of duodenal ulcer patients, as compared to the asymptomatic carriers. H. pylori cause activation of T-cells in the duodenum as well as in the stomach. Our observation of higher levels of CTLA-4+ cells in the duodenum of duodenal ulcer patients than in the asymptomatic carriers suggests that a suppressive T-cell response may be related to the development of duodenal ulcers.     

Rumenectomy-induced proliferation in duodenal villous epithelium is mechanistically related to the disappearance of statin, a non-proliferation-specific nuclear protein

We undertook this study to determine the effect of rumenectomy (a known cause of duodenal crypt cell hyperplasia) on the epithelial growth kinetics of the crypt-villus axis in rat duodenum. Ten rats were randomly assigned to control (gastrotomy) and experimental (rumenectomy) groups. After 14 days rats were sacrificed and representative sections were stained with the monoclonal antibody to statin, a non-proliferation-specific protein, by the immunoperoxidase procedure. In the control group, the mean percentages of statin-positive cells in the proximal duodenum, distal duodenum, proximal jejunum, and distal jejunum were 79 +/- 8.5, 79.5 +/- 5.7, 85 +/- 1.4, and 83.5 +/- 0.7, respectively. In the rumenectomy group, statin-positive nuclei were found in the region of the villous apices only, and the corresponding values for the above four areas were 26.2 +/- 4.9, 24.5 +/- 3.5, 31.7 +/- 4.5, and 80.5 +/- 2.1. Except for distal jejunum, the differences in statin expression in the control and experimental groups were significant (p less than 0.001). Rumenectomy leads to the disappearance of statin from the villous column cells of the duodenum and proximal small bowel. The lack of expression of statin in the rumenectomy group documents the potential usefulness of this measure in future studies in neoplasia were understanding of the proliferative status is of crucial importance.     

Thermal bile duct and duodenal protection during pancreatic cryoablation

Aim

To examine whether thermo-perfusion of the bile duct and duodenum may protect these organs during cryoablation of adjacent pancreatic tissue.

Study design

Cryoablation of the pancreatic tissue, adjacent to the common bile duct and duodenum was performed in two groups of pigs. In the experimental group, the bile duct and duodenum were protected during the cryo-procedure by intraluminal perfusion of warm saline. In the control group, cryoablation was performed without thermo-protection.

Results

All three animals in the control group developed duodenal perforation and abscesses and died within a week. All the pigs in the experimental group survived and on re-operation 14 days after the first procedure were found to have normal duodenum and bile duct adjacent to the cryoablated pancreatic tissue. Histological examinations confirmed these results.

Conclusion

The present study confirms the feasibility and efficacy of thermo-protection of the duodenum and common bile duct during cryoablation of the head of the pancreas.     

The effect of ferrous sulfate and pH on L-dopa absorption

Ferrous sulfate decreases L-dopa bioavailability in humans probably as a result of binding of L-dopa by iron in the gastrointestinal tract. This study was conducted to determine if iron by binding L-dopa decreases L-dopa absorption and to investigate the effect of different pH buffers on intestinal absorption of L-dopa in the presence and absence of ferrous sulfate. A rat model developed to examine drug absorption was used. Control animals had buffered [14C]L-dopa solutions injected into two in vivo closed segments of intestine; a 5-cm duodenal and a 5-cm proximal jejunal segment. These studies were conducted using solutions buffered at pH 5.5, 6.5, 7.5, and 8.5. An identical procedure was followed for experimental animals except ferrous sulfate was injected with the buffered L-dopa solutions. Ferrous sulfate resulted in a reduction in L-dopa absorption in the buffers at all pHs in both the duodenum and jejunum. The average reduction in L-dopa absorption in the presence of iron was 22.6% in the duodenum and 23.9% in the jejunum. There was a tendency for ferrous sulfate to cause a greater reduction in L-dopa absorption as the buffer pH increased. There was also a decrease in L-dopa absorption in the higher pH buffers in the absence of iron. Despite this latter result, in the jejunum there was an increase in the percent reduction in L-dopa absorption associated with ferrous sulfate as pH increased. Although this tendency was not as consistent in the duodenum as the jejunum, the combined results are compatible with the chemical model of increased L-dopa--iron binding as pH increases.     

Role of duodenal serotonin in the pharmacological effects of DOPA and dopamine in the isolated rat duodenum]

We have studied the responsibility of tissue serotonin reserves in the excito-motor effects induced by DOPA and dopamine on the isolated rat duodenum in vitro in certain experimental conditions. Two groups of experiments have been performed: first the determination of serotonin endogenous stores after administration of repeated high doses of DOPA and dopamine in the organ bath, secondly the evaluation of motor effects of DOPA and dopamine on rat duodenums experimentally depleted of their endogenous serotonin stores. Serotonin levels were lowered after DOPA and the excito-motor effect of this compound was suppressed in serotonin-depleted duodenums. After dopamine, serotonin tissue levels were not significantly lowered, and the excito-motor effect was observed whatever the serotonin stores may be, depleted or not. Our results are consistent with a relationship between the excito-motor effects of DOPA and serotonin release from endogenous stores; but, concerning dopamine, experimental proofs supporting this hypothesis have not been obtained.     

Morphometric analysis of the state of the intramural nervous apparatus of rat duodenum]

Structural organization of the intramural apparatus of the duodenum has been studied in normal white rats. By means of a planimeter, the area of the nerve cells and their nuclei has been estimated in serial sections of the cranial and caudal parts of the duodenum; a definite regularity on the nerve cell types distribution has been stated in different parts of the duodenum. Concentration of afferent nerve elements has been noted in the cranial part of the duodenum.     

The kinetics of intestinal calcium absorption in the rat: an analytical and model building study

The experimental data obtained from in vivo single pass perfusion of duodenal, jejunal, and ileal intestinal segments of 33- and 50-day-old rats have been used to test a series of models for calcium absorption. Each model was checked for the statistical validity and goodness-of-fit with the experimental data. The model adopted for the duodenum and jejunum had two major components, one saturable and the other nonsaturable, and a minor secretory component. This model was not applicable to ileal calcium absorption. Here the secretory component appeared to be much more important, and the absorption parameters varied in such a manner as to suggest that this intestinal segment was capable of short term autoregulation of dietary calcium absorption.     

Cadmium Reduces Contractile Responses of Rat Duodenum, In Vitro

The present study focuses on the effects of cadmium in drinking water on rat duodenum contractility, in vitro. Two experimental groups (n = 10 each) were administered with 15 ppm cadmium chloride in their drinking water for 1 and 2 months, respectively. Two separate groups (n = 10 each) were maintained in similar conditions but received no cadmium and acted as controls. After the experimental period, the duodenal segment responses were measured by means of an isotonic transducer. The average peak amplitude of acetylcholine-induced contractions was significantly decreased in both cadmium-treated groups. Incubation of duodena from the cadmium-free controls with atropine or in a calcium-free medium resulted in reduced contractility that was undistinguishable from that of the cadmium-treated rats. Cadmium reduces the contractile response apparently by directly or indirectly decreasing cellular calcium influx.     

Hymenolepis diminuta: Activity of anti-oxidant enzymes in different parts of rat gastrointestinal tract

The aim of this study was to assess the intensity of oxidative stress by measuring levels of lipid peroxidation products in the duodenum, jejunum and colon of rats infected with Hymenolepis diminuta and evaluate the effectiveness of protection against oxidative stress by measuring the glutathione levels and activity of anti-oxidant enzymes: superoxide dismutase, catalase, glutathione reductase and glutathione peroxidase.In exposed rats we observed a significant increase of lipid peroxidation products in the duodenum and jejunum. A significant decrease in superoxide dismutase activity in all the examined parts of the digestive tract was observed. Additionally, rats from 16 to 40 days post H. diminuta infection (dpi) had a decreased catalase activity in the colon, while at 60 dpi it increased. The glutathione peroxidase activity increased significantly in the colon at 60 dpi. The increase in glutathione reductase activity was observed in the colon in rats 60 dpi. There was a lack of changes in the levels of glutathione in the duodenum and a significant increase in its concentration in the jejunum and colon from 40 to 60 dpi and from 16 to 40 dpi, respectively. In this study we observed altered activity of anti-oxidant enzymes and glutathione level in experimental hymenolepidosis, as a consequence of oxidative stress. It may indicate a decrease in the efficiency of intestinal protection against oxidative stress induced by the presence of the parasite. The imbalance between oxidant and anti-oxidant processes may play a major role in pathology associated with hymenolepidosis.     

Morphological research on the effect of vagotomy on the parietal microflora of the stomach and duodenum

The effect of vagotomy on parietal microflora was studied in intact rats and rats with chronic experimental gastric ulcer using stereometry, as well as light, transmission and scanning electron microscopy. Vagotomy was found to increase the relative amount of parietal microflora on day 30 following denervation, especially in the duodenum and pylorus. Chronic gastric ulcers are also associated with a rise in the relative amount of parietal microflora.     

Two patterns of development of interstitial cells of Cajal in the human duodenum

At the end of the embryonic period of human development, c-kit immunoreactive (c-kit IR) cells identifiable as interstitial cells of Cajal (ICC) are present in the oesophagus and stomach wall. In the small and large bowel, c-kit-IR cells appear later (in the small bowel at 9 weeks, and in the colon at 10-12 weeks), also in the MP region. The object of this study was to determine the timing of appearance and distribution of c-kit IR cells in the human embryonic and foetal duodenum. I used immunohistochemistry to examine the embryonic and foetal duodenum for cells expressing CD117 (Kit), expressed by mature ICC and ICC progenitor cells and CD34 to identify presumed ICC progenitors. Enteric plexuses were examined by way of antineuron-specific enolase and the differentiation of smooth muscle cells was studied using antidesmin antibodies. At the end of the embryonic period of development, c-kit IR cells were solely present in the proximal duodenum in the form of a wide belt of densely packed cells around the inception of the myenteric plexus (MP) ganglia. In the distal duodenum, c-kit IR cells emerged at the beginning of the foetal period in the form of thin rows of pleomorphic cells at the level of the MP. From the beginning of the fourth month, the differences in the distribution of ICC in the different portions of the duodenum were established, and this relationship was still present in later developmental stages. In fact, in the proximal duodenum, ICC of the MP (ICC-MP), ICC of the circular muscle (ICC-CM) and ICC of the septa (ICC-SEP) were present, and in the distal duodenum ICC-MP and ICC-SEP only. In conclusion, in the humans there is a difference in the timing and patterns of development of ICC in the proximal duodenum compared to the distal duodenum.     

RADIATION EFFECTS ON CELL POPULATIONS IN THE INTESTINAL EPITHELIUM OF MICE AND ITS THEORY

Mice were exposed to 1000 R of X-rays to their trunks and sacrificed every day up to the tenth day after exposure. Cell counts were made on histological sections of the duodenum. The cell counts in the crypts were reduced to about 50% of the control value on the first day after exposure. The cell counts began to recover on the third day and an overshoot of 170% was observed on the fourth day; thereafter the crypt cell counts tended to return to the control level. The cell counts on the villi reached their minimum value on the third day after exposure. Following an overshoot on the sixth day, the villus cell counts returned to the control level by the tenth day. The above experimental results were analysed using a two-compartment model with a feedback term. A logistic proliferation was assumed for the proliferative crypt cells, while for the postmitotic villus cells the compartment was assumed to be a first in-first out type. The calculated results with this model are in general consistent with the experimental ones. The model seems to possess some essential features of the dynamics of cell renewal in the intestinal mucosa.     

Histo-blood group antigens act as attachment factors of rabbit hemorrhagic disease virus infection in a virus strain-dependent manner

Rabbit Hemorrhagic disease virus (RHDV), a calicivirus of the Lagovirus genus, and responsible for rabbit hemorrhagic disease (RHD), kills rabbits between 48 to 72 hours post infection with mortality rates as high as 50-90%. Caliciviruses, including noroviruses and RHDV, have been shown to bind histo-blood group antigens (HBGA) and human non-secretor individuals lacking ABH antigens in epithelia have been found to be resistant to norovirus infection. RHDV virus-like particles have previously been shown to bind the H type 2 and A antigens. In this study we present a comprehensive assessment of the strain-specific binding patterns of different RHDV isolates to HBGAs. We characterized the HBGA expression in the duodenum of wild and domestic rabbits by mass spectrometry and relative quantification of A, B and H type 2 expression. A detailed binding analysis of a range of RHDV strains, to synthetic sugars and human red blood cells, as well as to rabbit duodenum, a likely gastrointestinal site for viral entrance was performed. Enzymatic cleavage of HBGA epitopes confirmed binding specificity. Binding was observed to blood group B, A and H type 2 epitopes in a strain-dependent manner with slight differences in specificity for A, B or H epitopes allowing RHDV strains to preferentially recognize different subgroups of animals. Strains related to the earliest described RHDV outbreak were not able to bind A, whereas all other genotypes have acquired A binding. In an experimental infection study, rabbits lacking the correct HBGA ligands were resistant to lethal RHDV infection at low challenge doses. Similarly, survivors of outbreaks in wild populations showed increased frequency of weak binding phenotypes, indicating selection for host resistance depending on the strain circulating in the population. HBGAs thus act as attachment factors facilitating infection, while their polymorphism of expression could contribute to generate genetic resistance to RHDV at the population level.     

Intestinal IgA+ Cell Numbers as well as IgA, IgG, and IgM Contents Correlate with Mucosal Humoral Immunity of Broilers During Supplementation with High Fluorine in the Diets

Fluoride (F), a well-recognized harmful substance, is easily absorbed by the intestinal mucosa. The intestinal mucosal immune system is equipped with unique innate and adaptive defense mechanisms that provide a first line of protection against infectious agents. Meanwhile, immunoglobulins are the major secretory products of the adaptive immune system and their levels can be a strong indicator of a disease or condition. In this study, therefore, we investigated the effects of high dietary fluorine on the numbers of immunoglobulin A-positive (IgA⁺) cells in the lamina propria of intestines (duodenum, jejunum and ileum) by immunohistochemistry as well as on the contents of immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) in the mucosa of intestines (duodenum, jejunum, and ileum) by enzyme-linked immunosorbent assay (ELISA). A total of 280 1-day-old healthy avian broilers were randomly divided into four groups and fed on a corn–soybean basal diet as control diet (fluorine 22.6 mg/kg) or the same basal diet supplemented with 400, 800, and 1,200 mg/kg fluorine (high fluorine groups I, II, and III) in the form of sodium fluoride (NaF) for 42 days. The experimental data showed that the numbers of IgA⁺ cells as well as the IgA, IgG, and IgM contents were significantly decreased (P?<?0.01 or P?<?0.05) in the high fluorine groups II and III when compared with those of the control group. It was concluded that dietary fluorine in the range of 800–1,200 mg/kg significantly reduced the numbers of the IgA⁺ cells and the contents of aforementioned immunoglobulins in the intestines (duodenum, jejunum, and ileum) of broilers, which could finally impact the mucosal humoral immune function in the intestines by a way that reduces the lymphocyte population and/or lymphocyte activation.     

The effects of experimental uremia in rats on duodenal VIP levels and the interaction of VIP with duodenal epithelial cells

The effects of experimental uremia on the concentration of vasoactive intestinal peptide (VIP) in duodenum as well as on the interaction of this neuropeptide with the corresponding epithelial cells were studied in rats. Duodenal VIP concentration was significantly decreased in uremic rats as compared to control animals. The specific binding of VIP to duodenal epithelial cells increased in rats with uremia due to an increase in the number of VIP receptors rather than a change in the binding affinity or in the extent of VIP degradation. On the other hand, the efficacy but not the potency of VIP upon cyclic AMP generation varied in parallel to that observed at the receptor level.     

Absorption and metabolism of purines by the small intestine of the chicken.

1. Absorption of purines and their metabolism by the small intestine were estimated by using the everted gut sacs from the duodenum, jejunum and ileum of the chicken. 2. When no purine was added to the mucosal fluid, large amounts of uric acid, much less but appreciable adenine, hypoxanthine and xanthine and no detectable guanine were released from both sides of all segments of the small intestine, and these released amounts were largest in the duodenum. 3. Similar absorption rates of adenine from the jejunum and ileum were about 1.7-3.0 times as high as those of hypoxanthine and uric acid from these intestines and those of adenine and uric acid from the duodenum (P less than 0.05). 4. Guanine was not absorbed unchanged from any segments of the intestine and a little xanthine was absorbed only from the jejunum and ileum. 5. Guanine and xanthine seem to be absorbed in uric acid form, hypoxanthine in xanthine and uric acid forms and adenine in hypoxanthine form, from the small intestine especially from the jejunum. 6. Adenine, guanine, xanthine and hypoxanthine were greatly metabolized in the mucosa of the duodenum, and the conversions of hypoxanthine to xanthine and uric acid were most active.     

Cholecystokinin-producing (I) cells of intestinal mucosa in dexamethasone-treated rats

The aim of this study was to investigate the morphological, immunohistochemical and ultrastructural changes of cholecystokinin-producing (I) cells of gastrointestinal mucosa in dexamethasone-treated rats (D). After 12-daily intraperitoneal administration of 2mg/kg dexamethasone, rats developed diabetes similar to human diabetes mellitus type 2. The mean diameter of the duodenum was significantly decreased due to significant reduction of volume fraction and profile area of lamina propria. There was a decrease in volume fraction and number of cholecystokinin (CCK)-producing cells per mm(2) of mucosa, as well as their numerical density, but without statistical significance. Also, dexamethasone induced appearance of hyperactive duodenal I-cells with small number of granules and dilated endoplasmic reticulum. In conclusion, the present study showed that morphological changes in duodenum cholecystokinin-producing (I) cells occurred in diabetic rats, in a manner which, suggests compensatory effort of CCK cells in diabetic condition.     

Interaction between chitosan and oil under stomach and duodenal digestive chemical conditions

Chitosan, the N acetylated derivative of chitin, has an effect on the absorption of dietary lipids, but there is not enough scientific knowledge about the mechanism. To study the interaction between chitosan and oil, the action of this biopolymer has been evaluated through an experimental model of the stomach and duodenum tract, although the enzimatic activity had not been evaluated. We microscopically confirmed that chitosan in a hychloridic acid medium (pH 1.0-2.0) emulsified lipids and the emulsion was a water in oil in water type (w/o/w). When the pH value and speed of agitation were increased to mirror the duodenum medium conditions under which lipids are absorbed, the emulsion capacity was better with an increased number of droplets and the emulsion continued as the w/o/w type. At pH 6.2, chitosan precipitated and lipids were entrapped in the formed flocculus. The binding oil was quantitatively determined, and we also demonstrate that a larger oil quantity induced less retention, while the chitosan characteristics had no influence. These observations allow us to postulate that the interaction between chitosan and oil inhibited duodenal absorption and enhanced lipid excretion.     

Morphofunctional characteristics of the duodenum in the early stages of experimental escherichiosis

Using the model of experimental colibacillosis in mice morphological, immunomorphological and morphometrical studies of duodenum 1 to 24 hours after inoculation were performed. Typical dynamics of cellular composition in the intestinal wall, accompanied with increased lymphoplasmacellular infiltration, and dystrophic changes in cells of submucosal and intermuscular neuroplexuses were found. The data obtained testify, that the infectious process at the acute state of experimental colibacillosis has an immune character (immediate hypersensitivity of local type), characterised by increasing in immunoglobulin-containing cells and including in this process of mast and endocrine cells.     

Neuropeptide Y, peptide YY, and pancreatic polypeptide modulate duodenal and colonic motility at a thoracic spinal site in rats.

Neuropeptide Y, PYY, and PP (200 pmol) alter intraluminal pressure in the duodenum and colon of rats following their administration into the thoracic (T8-T10) region of the spinal cord. Neuropeptide Y decreases the tone of the duodenum and the colon following intrathecal (T8-T10) administration prior to an increase in tone to baseline or greater. There is no effect on intraluminal pressure of either the duodenum or the colon following intrathecal administration of NPY or PP into the lumbar (L4-L5) region of the spinal cord. Following intrathecal (T8-T10) administration of PYY and PP, increases in intraduodenal pressures are observed (+2.1 and +3.0 mmHg from saline baseline). Phasic contractions of the duodenum are increased following intrathecal administration of PYY into the thoracic spinal cord of rats. Neuropeptide Y, PYY, and PP increase intracolonic pressure +2.2, +3.3, and +3.7 mmHg from saline baseline, respectively. Phasic contractions of the colon are increased following PP intrathecal thoracic administration. Responsiveness of the duodenum or colon to the different ligands of the PP-fold peptide family in the absence of alpha-adrenergic blockade did not vary. The increases in intraluminal pressure of the duodenum and colon following intrathecal administration of the PP-fold peptides are attenuated by both alpha-1 adrenergic (prazosin) and alpha-2 adrenergic (yohimbine) blockade. There is a difference in responsiveness of the colon between the ligands of the PP-fold family in the presence of the alpha-2 adrenergic blockade. The findings of this study indicate that duodenal and colonic motility are modulated by the PP-fold peptides at thoracic spinal sites via alteration of sympathetic outflow.