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Application of a new morphometry system based on SEM stereo-pairs to the study of intestinal mucosa of rodents.

A new morphometry system for submicroscopic three-dimensional structures was developed on the same principles as for the aerial survey using SEM stereo-pairs. This computer graphic system was applied to the analysis of the surface features of the intestinal mucosa. After removing the epithelial layer by prolonged osmication, core structures of the intestinal villi were exposed and 100 villi each from rat and mouse were measured. Average height, basal area and surface area of a single core of the rat were 188 microns, 20,200 microns2 and 93,500 microns2, respectively. Those of the mouse were 148 microns, 7,530 microns2 and 37,100 microns2, respectively. Surface amplifications by the rat and the mouse villi, after compensating for epithelial thickness, were calculated as 3.5 and 4.3, respectively; though amplifications based on the villous core were 4.6 and 4.9, respectively. These three-dimensional features of the intestinal mucosa were illustrated as submicroscopic maps by drawing their contour lines. It was demonstrated that the present morphometry system makes it possible to know not only the average features of a large sample, but also a variety of features of individual structures which were directly observed under SEM.

Animals↗

Effects of oral nutritional supplementation on the intestinal mucosa of patients with AIDS.

Weight loss is a major component of the clinical syndrome in patients with acquired immunodeficiency syndrome (AIDS). The impact of malnutrition on the outcome of the disease has been unappreciated in many investigations. The authors evaluated the effects of oral nutritional supplementation on the morphology and immunology of the intestinal mucosa of patients with AIDS. Twelve patients with AIDS without diarrhea or opportunistic infections, with at least 10% of body weight loss over 1 year, were submitted to anthropometric measures, peripheral blood T-lymphocyte counts, and peroral jejunal biopsy before and after oral nutritional supplementation. An industrialized peptide-based formula containing omega-3 fatty acids was given for 6 weeks. Jejunal samples were analyzed by histomorphometry, including villous-to-crypt ratio, lamina propria, and intraepithelial lymphocyte count. Immunologic assessment of the intestinal mucosa was made by indirect immunoperoxidase using monoclonal antibodies against CD3, CD4, and CD8. Seven patients with irritable bowel syndrome and two healthy volunteers were selected as a control group for histologic and immunohistochemical comparisons. After 6 weeks the patient group maintained their body weight and increased their tricipital fold. The number of peripheral blood T cells, albumin, transferrin, and the number of CD3+, CD4+, and CD8+ cells in jejunal mucosa as well as the intestinal morphometry remained stable. Oral supplementation contributed to maintaining body weight and may constitute a reasonable adjuvant therapeutic tool against AIDS progression.

Acquired Immunodeficiency Syndrome↗

Hydrolytic activity toward pyridoxine-5'-beta-D-glucoside in rat intestinal mucosa is not increased by vitamin B-6 deficiency: effect of basal diet composition and pyridoxine intake.

Pyridoxine-5'-beta-D-glucoside (PNG), a glycosylated form of dietary vitamin B-6, is partially hydrolyzed in the small intestine by the cytosolic enzyme pyridoxine-5'-beta-D-glucoside hydrolase (PNG hydrolase) and by the brush border enzyme lactase phlorizin hydrolase (LPH) to release free pyridoxine (PN). This laboratory has previously shown that PNG hydrolase activity is inversely related to dietary vitamin B-6 in rats and guinea pigs. The current investigation was done to examine the effect of dietary PN on PNG hydrolytic activity and its distribution. Nutrient compositional differences between the AIN-76A and AIN-93G purified diets that were unrelated to vitamin B-6 were also examined in relation to PNG hydrolysis in rat small intestinal mucosa. Study one included rats (n = 29) that were fed the AIN-93G diet providing a range of PN concentrations for 5 wk. Rats (n = 49) in study two were fed either AIN-76A or AIN-93G each with graded concentrations of PN. In both studies, rat growth and plasma and liver pyridoxal 5'-phosphate (PLP) concentrations increased (P < 0.05) with increasing concentrations of dietary PN. PNG hydrolytic activity localized to the brush border membrane was five times that measured in the cytosol. Cytosolic PNG hydrolytic activity increased significantly with increasing dietary PN concentration in rats fed the AIN-76A, but not AIN-93G diet. Activity in the mucosal total membrane fraction did not increase in proportion to dietary PN concentration for either diet. Regardless of dietary PN concentration, the basal nutrient composition of the diets affected growth and PNG hydrolytic activity in intestinal mucosa. In contrast to previous results from this laboratory, intestinal hydrolytic activity toward PNG did not increase in vitamin B-6-deficient rats.

Animal Feed↗

[Expression of proliferating cell nuclear antigen of the intestinal mucosa during critical intraperitoneal infection].

OBJECTIVE: To explore the expression and significance of proliferating cell nuclear antigen (PCNA) in intestinal epithelial cells during critical intraperitoneal infection. METHODS: A total of 60 SD rats were divided randomly to two groups: control group and infection group (30 rats in each group). Cecal ligation and puncture (CLP) was done in the infection group, and laparotomy only in the control group. Immunohistochemical technique was applied for assaying PCNA index of the jejunum and ileum samples on postoperative day 1, day 2 and day 4. RESULTS: The inflammatory reaction of small intestine mucous membrane was severer in the infection group than the control group. Compared with the control group, the PCNA indexes on day 1 and day 2 in the infection group were higher significantly (both P<0.01). The highest PCNA index was seen on postoperative day 1 in the infection group, then it lowered gradually (both P<0.01). CONCLUSION: The PCNA index of intestinal epithelial cells is elevated during the early period of critical intraperitoneal infection. The findings indicate that PCNA index is related with the injury and repair of intestinal mucosa during critical intraperitoneal infection.

Abdominal Cavity↗

[Intestinal mucosa in rats with iron deficiency anemia].

Eighteen albino rats at the age of 15 days were separated in 2 groups of 9 and fed cow's milk exclusively. The milk supplied to the control rats (group I) was supplemented with iron and copper. The months later, the rats were scarificed. The animals of group II were severely anaemic. In each rat, a histological examination of gastric (in group II, only in 2 rats) and jejunal mucosa as well as measurements of total thickness, villous height, epithelial cell height and mitotic index were made. Histology was normal in all the rats. Measurements gave similar results in both groups except for the epithelial cell height which was significantly higher in anaemic rats than in controls. The authors take issue with the methodology followed in previous studies concerning iron-deficient children and suggest that the causal relation between iron deficiency and structural changes of intestinal mucosa in children has not yet been proven.

Anemia, Hypochromic↗

Distribution of glycosphingolipids and ceramide of rat small intestinal mucosa.

Previous studies have suggested that glycosphingolipids may be involved in a number of physiological functions of the small intestinal mucosa. Regional variations in many of these processes exist along the length of this organ. In the present studies, the glycosphingolipid and ceramide composition of the proximal, middle and distal thirds of the rat small intestine were characterized and compared. Mono- and trihexosylceramide were the major neutral glycolipids and hematoside (GM3), the principal ganglioside of this organ. Monohexosylceramide was the major glycolipid of the proximal segment, whereas trihexosylceramide predominated in the distal segments. The total content of neutral glycolipids, ceramide and gangliosides as well as the content of the individual glycosphingolipids and ceramide were highest in the distal segment, intermediate in the middle and lowest in the proximal segment. Additionally, regional variations were noted in the fatty acid composition of the major glycosphingolipids. These differences in the composition of glycolipids and ceramide along the length of the intestine may be responsible, at least partially, for the regional functional specialization seen in this organ.

Animals↗

[Effect of fluorine on enzyme activity in the small intestine mucosa during absorption of sodium, potassium, monosaccharides and amino acids].

Effect of NaF on ATP-ase, creatine kinase, acid and basic phosphatases activity of small intestine mucosa in white rats during enteral administration of NaCl, KCl solutions has been studied under conditions of acute experiment. Inhibition of the Mg2+-ATP-ase activity by 13%, general ATP-ase activity by 25%, creatine kinase by 22% and a 2.2-3 fold inhibition of Na, K+-ATP-ase activity is observed. Acid and basic phosphatase activity does not change, swelling of mucosa is observed. The acid phosphatase activity in the intestinal contents increases 1.5 times, basic phosphatase activity--1.7 times, creatine amount--1.7 times, Pi amount 1.8 times. In experiments in vitro F- produces 20% activation of the basic phosphatase of mucosa and a 2.6-fold inhibition of the acid phosphatase. Rate of fructose absorption falls by 34%, that of methionine--by 29%, glucose--by 24%, glutaminic acid--by 10%. Activity of general ATP-ase in this case decreases by 22, 15, 27, 20% respectively. It is supposed that the F- effect results in destabilization of the membrane structures of the intestine mucosa.

Acid Phosphatase↗

Nuclear binding of cortisol in intestinal mucosa and liver of a teleost fish (Salmo gairdnerii irideus).

Nuclear binding of corticosteroids in fish tissues was investigated in two target organs of the trout Salmo gairdnerii irideus: the liver and the intestinal mucosa. Incubation of intact nuclei with [3H]-cortisol or [3H]-dexamethasone failed to demonstrate high-affinity binding of these steroids to proteins. Exchange assay of [3H]-cortisol in high-salt nuclear extracts indicated an association constant Ka = 1.9 X 10(4) M-1 for intestinal mucosa and 2.1 X 10(4) M-1 for liver. In sea water-adapted trout, the association constant remained the same as in fresh water. These results extend previous observations obtained on the cytosol which showed that no high-affinity receptors could be disclosed in fish tissues using these two corticosteroids.

Animals↗

The influence of hardly digestive starch granules on sucrase and isomaltase in small intestinal mucosa of rats.

The effects of potato-starch granules (PSG) on sucrase and isomaltase activities in the small intestinal mucosa of rats were examined by gel filtration on a Sephacryl S-300 column. Young and adult rats were administered the diet containing 50% of either PSG or pregelatinized potato starch (PPS) as a control for 7 days. Mucosal homogenates were prepared from the small intestine and separated into their component disaccharidases on the column. The sucrase activity, increased by feeding young rats on the PSG diet, was detected in the sucrase-isomaltase complex by changing the activity ratio of the two enzymes. In adult rats, however, the complex seemed to be mature and the increased sucrase moiety was newly combined with a free isomaltase moiety and comprised a portion of the complex. These changes were observed not only in soluble disaccharidases but also in membrane-bound ones. Furthermore, there was a remarkable change of sucrase activity in the distal portion of the small intestine rather than in the proximal.

Aging↗

Secretory component, alpha 1-antitrypsin and lysozyme in IgA deficient children. An immunohistochemical evaluation of intestinal mucosa.

Nine children with IgA deficiency were studied in order to evaluate by the immunoperoxidase technique the behaviour of secretory component (SC), alpha 1-antitrypsin (alpha 1-AT), lysozyme and esterase in biopsies of intestinal mucosa. In none of the studied patients was SC found to be lacking, suggesting that the epithelial transport mechanism of IgA across enterocytes was relatively normal. The distribution of SC activity in immunodeficient children differed however from that seen in control intestinal mucosa in its non-uniform distribution on the villus, abnormal retention in the Golgi region of enterocytes or exclusive activity confined to the proliferating compartment of the villus. The staining of alpha 1-AT in enterocytes was clearly obvious in all studied cases with no alteration in zonal distribution when compared with normal human mucosa. The lysozyme staining pattern was seen exclusively in Paneth cells. The non-specific esterase positive enterocytes observed in control mucosa failed to stain in biopsies from IgA deficient children. The results of this study of SC, alpha 1-AT, lysozyme and esterase may indicate that IgA deficiency is not related to a defect in enterocyte transport of immunoglobulins and confirms previously reported findings indicating the lymphoid B-cell compartment to be altered.

Biopsy↗

Protection of the intestinal mucosa during ischaemia by intraluminal perfusion.

The function of the intestinal mucosa immediately after one hour's ischaemia was examined by means of tests in vivo and in vitro. During the ischaemia, the intestinal loop was perfused with media of different compositions, in an attempt to assess which provided the best protection of the epithelium from the deleterious effects of the ischaemia. The absorption of water, ions and glucose was then monitored in vivo, and the uptake of phenylalanine and beta methyl-glucoside by slices of mucosa was determined in vitro. The unprotected mucosa loses all active transport capacity in vitro following one hour's ischaemia, and is the site of a pronounced loss of water and ions into the lumen in vivo. Glucose absorption in vivo is also abolished. If the loop is perfused during the ischaemia with glucose-containing Krebs bicarbonate buffer, much of the transport capacity in vitro is retained; the loss of ions and water is prevented, and glucose absorption in vivo occurs. Perfusion during the ischaemia with other media, such as isotonic mannitol, Krebs bicarbonate buffer, or Ringer-lactate solution, results in a marked protection of the mucosa, in comparison with the unperfused loop, but the effects are not as pronounced as those of the glucose-containing buffer. It is concluded that the act of perfusing the intestine is the most beneficial factor, but that the presence of glucose in the perfusate does afford added protection.

Animals↗

Effect of dietary copper on intestinal mucosa enzyme activity, morphology, and turnover rates in weanling pigs.

Twenty-four pigs from four litters weaned at 21 d of age (6.6 kg of BW) were used to evaluate the influence of 250 ppm of dietary Cu on intestinal mucosa glucose-6-phosphatase (GP), alkaline phosphatase (AP), and adenosine triphosphatase (ATPase) activity; mucosal morphology; and the turnover rate of the intestinal mucosa throughout the gastrointestinal tract. Pigs were allotted into four pens of six pigs each based on sex, litter, and weight. Pens were then assigned to one of two treatments: 1) corn-soybean meal-whey diet with no antimicrobials (CO), or 2) CO + 250 ppm of Cu. Pigs were fed twice daily an amount approximately equal to ad libitum intake for 14 d. On d 14, pigs were injected i.p. with [3H]thymidine (50 microCi/kg of BW) 10 h after the morning meal. One pig from each pen was euthanatized at 1, 6, 12, 20, 32, and 44 h postinjection, and intestinal tissue was collected from the duodenum, two jejunum sites (upper and lower), ileum, cecum, and colon. The activity of GP and AP in the lower jejunum tended to decrease in pigs fed Cu (P less than .11, P less than .08, respectively). The ATPase activity was not affected by treatment (P greater than .10). Crypt death, villus height, or epithelial cell size (P greater than .10) were not affected by feeding Cu. Migration rate of epithelial cells up the villus was also not affected by treatment (P greater than .10).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphatases↗

Hepatitis B antigen inhibitor in human faeces and intestinal mucosa.

Hepatitis B antigen (HB Ag) positive sera became negative after in-vivo incubation with homogenates of human faeces or intestinal mucosa. This was found to occur in all sera tested by various methods. These findings suggest the existence in the human intestine of a substance able to inactivate the HB Ag and that it is not an antibody or of the nature of interferon. The presence of an inhibitor could explain why B-type hepatitis is seldom if ever faecally transmitted and also the low oral infectiousness of the B virus.

Animals↗

Functional and metabolic changes in intestinal mucosa of rats after enteral administration of ornithine alpha-ketoglutarate salt.

BACKGROUND: Ornithine alpha-ketoglutarate salt efficiently improves the nutritional status of protein-depleted patients. Our aim was to explore the effects of ornithine alpha-ketoglutarate supplementation on intestinal physiology in healthy animals. METHODS: Rats were given a nutritive mixture supplemented with ornithine alpha-ketoglutarate (1 g.kg-1 per day) by enteral route for 7 days. Controls received the diet supplemented with casein acid hydrolysate under isoenergetic and isonitrogenous conditions. RESULTS: An adaptive hyperplasia of the villi and an increase in the brush-border hydrolase activities were observed in rats receiving ornithine alpha-ketoglutarate. Because of the high ornithine aminotransferase activity, ornithine alpha-ketoglutarate-derived ornithine was extensively transaminated with a concomitant enhancement of ornithine decarboxylation. Surprisingly, with glutamate and putrescine, the products of ornithine transamination and decarboxylation, gamma-aminobutyric acid accumulated (10-fold to 16-fold) dramatically in the intestinal mucosa of rats treated with ornithine alpha-ketoglutarate. Because gamma-aminobutyric acid formation was completely prevented by the diamine oxidase inhibitor aminoguanidine but was not modified after inactivation of ornithine aminotransferase by 5-fluoromethylornithine, it is evident that gamma-aminobutyric acid is formed in the mucosa from ornithine via putrescine as an intermediate. CONCLUSIONS: It is assumed that enhanced gamma-aminobutyric acid formation in the intestinal mucosa by ornithine alpha-ketoglutarate treatment might be of physiologic importance in the regulatory processes of cell growth and differentiation.

Amino Acids↗

[State of blood flow in gastric and small-intestinal mucosa in acute diffuse peritonitis].

One of the most severe complications of the postoperative period in patients with diffuse peritonitis is known to be erosive ulcerous injuries of the gastrointestinal tract mucosa (in 29 of 150 patients). The blood flow state of the gastric and intestinal mucosa was studied with the help of contact microfluorimeter under conditions of experimental peritonitis. Disturbances of the intramural blood flow of the gastrointestinal tract have been found which is a cause of the formation of acute ulcers and erosions of the mucosa.

Acute Disease↗

[Determination of glutamine in intestinal mucosa by pre-column derivatization/reversed-phase high performance liquid chromatography with fluorescence detection].

A high performance liquid chromatographic pre-column derivatization method with fluorescence detection for the analysis of glutamine (Gln) in rat intestinal mucosa is presented. Gln was derivatized with o-phthalaldehyde and 3-mercaptopropionic acid under an alkaline condition and separated by reversed-phase liquid chromatography on a Lichrosorb RP18 column (150 mm x 4.6 mm i.d., 5 microm). The mobile phase was consisted of 50 mmol/L phosphate buffer (pH 7.0)-acetonitrile (94:6, V/V) with a flow rate of 2.0 mL/min. The excited and emitted wavelength were selected at 230 nm and 389 nm respectively. The volume ratio of samples and derivatization reagent solution was 4:1 (V/V). The detection limit of Gln was 25 micromol/L (S/N= 3.5) and the regression equation was A = 16.9405C + 179.9339, r = 0.9996 at the linear range of 50-3200 micromol/L. The day-to-day deviation was 6.97% (n = 3) and the retention time of Gln was 3.158 min. This method is rapid, simple and highly sensitive, and has been applied to the determination of Gln in intestinal mucosa.

Animals↗

Concanavalin A promotes adherence of Salmonella typhimurium to small intestinal mucosa of rats.

A number of dietary lectins have been shown to resist proteolytic digestion. These lectins interact with the small intestinal mucosa causing structural and functional changes. Concomitant to these changes, bacterial overgrowth was reported and a possible interaction between lectins and bacteria in the small intestine was postulated. The aim of this study was to investigate the effect of various lectins on adherence of Salmonella typhimurium to both isolated small intestinal enterocytes and ligated intestinal loops. Isolated intestinal cells or ligated intestinal loops were incubated with [3H] adenine-S. typhimurium in the presence or absence of concanavalin A, phytohemagglutinin, peanut agglutinin, and wheat germ agglutinin. Only concanavalin A promoted the adherence of various strains of nonfimbriated S. typhimurium to isolated viable intestinal cells. Other lectins showed no effect on the adherence. In situ studies showed that bacterial binding was increased in concanavalin A-treated intestinal loops, supporting the significance of the experiments in vitro. These data suggest that lectins may act by promoting bacterial adherence to the small intestine, thereby facilitating colonization and infection, and leading to bacterial overgrowth.

Animals↗