Marker Of Intestinal Integrity Research Articles

Assessment of the Impact of Humic Acids on Intestinal Microbiota, Gut Integrity, Ileum Morphometry, and Cellular Immunity of Turkey Poults Fed an Aflatoxin B1-Contaminated Diet.

A recent study published data on the growth performance, relative weights of the organs of the gastrointestinal tract, liver histology, serum biochemistry, and hematological parameters for turkey poults fed an experimental diet contaminated with aflatoxin B1 (AFB1) and humic acids (HA) extracted from vermicompost. The negative effects of AFB1 (250 ng AFB1/g of feed) were significantly reduced by HA supplementation (0.25% w/w), suggesting that HA might be utilized to ameliorate the negative impact of AFB1 from contaminated diets. The present study shows the results of the remaining variables, as an extension of a previously published work which aimed to evaluate the impact of HA on the intestinal microbiota, gut integrity, ileum morphometry, and cellular immunity of turkey poults fed an AFB1-contaminated diet. For this objective, five equal groups of 1-day-old female Nicholas-700 turkey poults were randomly assigned to the following treatments: negative control (basal diet), positive control (basal diet + 250 ng AFB1/g), HA (basal diet + 0.25% HA), HA + AFB1 (basal diet + 0.25% HA + 250 ng AFB1/g), and Zeolite (basal diet + 0.25% zeolite + 250 ng AFB1/g). In the experiment, seven replicates of ten poults each were used per treatment (n = 70). In general, HA supplementation with or without the presence of AFB1 showed a significant increase (p < 0.05) in the number of beneficial butyric acid producers, ileum villi height, and ileum total area, and a significant reduction in serum levels of fluorescein isothiocyanate-dextran (FITC-d), a marker of intestinal integrity. In contrast, poults fed with AFB1 showed a significant increase in Proteobacteria and lower numbers of beneficial bacteria, clearly suggesting gut dysbacteriosis. Moreover, poults supplemented with AFB1 displayed the lowest morphometric parameters and the highest intestinal permeability. Furthermore, poults in the negative and positive control treatments had the lowest cutaneous basophil hypersensitivity response. These findings suggest that HA supplementation enhanced intestinal integrity (shape and permeability), cellular immune response, and healthier gut microbiota composition, even in the presence of dietary exposure to AFB1. These results complement those of the previously published study, suggesting that HA may be a viable dietary intervention to improve gut health and immunity in turkey poults during aflatoxicosis.

Daily yogurt consumption does not affect bone turnover markers in men and postmenopausal women of Caribbean Latino descent: a randomized controlled trial

BackgroundCaribbean Latino adults are at high risk for osteoporosis yet remain underrepresented in bone research. This increased risk is attributed to genetics, diet, and lifestyle known to drive inflammation and microbial dysbiosis.ObjectiveThe primary objective of this study was to determine whether consuming 5 oz of yogurt daily for 8wks improves bone turnover markers (BTMs) among Caribbean Latino adults > 50 years; and secondarily to determine the impact on the gut microbiota and markers of intestinal integrity and inflammation.MethodsFollowing a 4wk baseline period, participants were randomized to an 8wk whole fat yogurt intervention (n = 10) daily, containing only Streptococcus thermophilus and Lactobacillus bulgaricus, or to an untreated control group that did not consume yogurt (n = 10). Blood and stool samples collected at week-0 and week-8 were used to assess BTMs, inflammation, intestinal integrity biomarkers, and gut microbiota composition, short chain fatty acids (SCFAs), respectively. Data were evaluated for normality and statistical analyses were performed.ResultsParticipants were 55% women, with a mean age of 70 ± 9 years, BMI 30 ± 6 kg/m2, and serum C-reactive protein 4.8 ± 3.6 mg/L, indicating chronic low-grade inflammation. Following 8wks of yogurt intake, absolute change in BTMs did not differ significantly between groups (P = 0.06–0.78). Secondarily, absolute change in markers of inflammation, intestinal integrity, and fecal SCFAs did not differ significantly between groups (P range 0.13–1.00). Yogurt intake for 8wks was significantly associated with microbial compositional changes of rare taxa (P = 0.048); however, no significant alpha diversity changes were observed.ConclusionsIn this study, daily yogurt did not improve BTMs, inflammation, intestinal integrity, nor SCFAs. However, yogurt did influence beta diversity, or the abundance of rare taxa within the gut microbiota of the yogurt group, compared to controls. Additional research to identify dietary approaches to reduce osteoporosis risk among Caribbean Latino adults is needed.Trial registrationThis study is registered to ClinicalTrials.gov, NCT05350579 (28/04/2022).

Zinc Deficiency And sTNF-RII Are Associated With Worse COVID-19 Outcomes

BackgroundZinc (Zn) is known for its substantial involvement in the immune response as an antioxidant and anti-inflammatory agent. Zn plasma levels’ clinical significance in coronavirus disease (COVID) diagnosis is not yet fully established. ObjectiveWe assessed the association between Zn deficiency, gut integrity, inflammation, and COVID-19 outcomes. MethodsA prospective observational cohort in which plasma Zn, soluble tumor necrosis factor alpha receptor II (sTNF-RII) intestinal fatty-acid binding protein (IFABP; marker of intestinal integrity), and zonulin levels (intestinal permeability) were collected from participants during the acute phase of a confirmed COVID-19 diagnosis. Zn was modeled as continuous and binary, categorized as Zn deficiency (Zn < 75 μg/dL) and Zn sufficiency (Zn ≥ 75 μg/dL). COVID-19 outcomes were classified according to the World Health Organization clinical progression scale. We used cumulative probit regression to assess if suboptimal Zn levels, gut, and inflammatory markers increase the likelihood of worse COVID-19 outcomes. ResultsZn deficiency was independently associated with 63% higher predicted odds of worse COVID outcomes. Increases in sTNF-RII {unadjusted odds ratio (uOR): 3.43 [95% confidence interval (CI): 2.02, 5.82]} and zonulin [uOR: 1.83 (95% CI: 1.21, 2.76)] levels were associated with greater odds of worse COVID outcomes. IFABP was not associated with worse COVID outcomes [uOR: 1.12 (95% CI: 0.82, 1.53)] or acute Zn deficiency [uOR: 1.35 (95% CI: 0.79, 2.35)]. The adjusted predicted odds of worse COVID outcomes are 3-fold higher (P = 0.04) for every one-unit decrease in Zn and is more than 2 times greater odds of COVID severity (P = 0.01) for every 1-unit increase in sTNF-RII. ConclusionZn deficiency and inflammation were independently associated with greater odds of worse COVID outcomes.

Association of zinc deficiency with infectious complications in pediatric hematopoietic stem cell transplantation patients.

Zinc plays essential roles in immune function and epithelial integrity. Patients undergoing hematopoietic stem cell transplantation (HSCT) often have low plasma zinc levels because of poor intake and diarrhea. We hypothesized that patients with zinc deficiency before HSCT had worse infectious complications after HSCT compared with patients with normal zinc levels. Citrulline, a marker of intestinal integrity, was also hypothesized to be lower in patients with zinc deficiency. Thirty patients undergoing HSCT at Ramathibodi Hospital during March 2020-September 2021 were enrolled. Blood samples for plasma zinc and citrulline were collected during the HSCT period. The 14- and 90-day outcomes after HSCT were prospectively recorded. Twelve of 30 (40%) patients had zinc deficiency before HSCT. Zinc-deficient patients were younger (median (interquartile range): 6 (8.8) vs 13 (5.8) years old; p = 0.017). Zinc levels tended to increase after admission in both groups. Patients with zinc deficiency had lower citrulline levels than those with normal zinc levels. Citrulline levels decreased in both groups after stem cell infusion, and the level was not significantly different between the two groups. Zinc-deficient patients had a higher rate of bacterial infection within 90 days after HSCT than those with normal zinc levels (6 in 12 patients (50.0%) vs 1 in 18 patients (5.6%); odds ratio [OR]: 17.0; 95% confidence interval [CI]: 1.68-171.70; p = 0.016). This remained significant after adjustments for age (adjusted OR: 12.31; 95% CI: 1.084-139.92; p = 0.043). The prevalence of zinc deficiency in pediatric patients undergoing HSCT was high. Zinc-deficient patients had lower citrulline levels and higher incidence of bacterial infection after HSCT. However, citrulline level was not different between patients with and without bacterial infections. It is worth to investigate whether zinc supplementation before HSCT can reduce bacterial infection after HSCT.

Evaluation of digestively resistant or soluble fibers, short- and medium-chain fatty acids, trace minerals, and antibiotics in nonchallenged nursery pigs on performance, digestibility, and intestinal integrity.

Three experiments (EXP) were conducted to determine the effect of feed additives on performance, intestinal integrity, gastrointestinal volatile fatty acids (VFA), and energy and nutrient digestion in nonchallenged nursery pigs. In EXP 1, 480 pigs (6.36-kg body weight, BW) were placed into 96 pens with 5 pigs/pen, and allotted to 1 of 10 dietary treatments: 1) negative control containing no feed additive (NC), 2) NC + 44 mg chlortetracycline and 38.5 mg tiamulin/kg diet (CTsb), 3) NC + 5% resistant potato starch (RSpo), 4) NC + 5% soluble corn fiber (SCF), 5) NC + 5% sugar beet pulp (SBP), 6) NC + 0.30% fatty acid mix (FAM), 7) NC + 0.10% phytogenic blend of essential oils and flavoring compounds (PHY), 8) NC + 50 mg Cu and 1,600 mg zinc oxide/kg diet (CuZn), 9) NC + 5% resistant corn starch (RScn), and 10) NC + 0.05% β-glucan (BG) for 28 d. There was no impact of dietary treatment on BW gain or feed intake (P ≥ 0.22). Pigs fed diets containing SCF, CTsb, and RSpo resulted in microbial community differences compared to pigs fed the NC (P < 0.05). In EXP 2, 48 barrows (12.8 kg BW) were selected at the end of EXP 1 and fed the same dietary treatments they had previously received: 1) NC, 2) NC + 5% RScn, 3) NC + 5% SCF, and 4) NC + FAM for 8 d. There was no effect of feeding diets containing RScn, SCF, or FAM on in vivo intestinal permeability (P ≤ 0.21). Ileal or colon pH, concentrations of VFA did not differ due to dietary treatment (P ≥ 0.36), but pigs fed diets containing FAM resulted in a greater butyric acid concentration in the cecum compared to pigs fed the NC (P ≤ 0.05). In EXP 3, 156 pigs (6.11 kg BW) were placed into 52 pens with 3 pigs/pen and allotted to 1 of 4 dietary treatments arranged in a factorial manner: 1) NC, 2) NC + 5% RSpo, 3) NC + 0.30% FAM, and 4) NC + 5% RSpo + 0.30% FAM for 24 d. Feeding pigs diets containing RSpo did not affect BW gain (P = 0.91) while pigs fed diets containing FAM grew improved BW gain (P = 0.09). Colonic butyric acid concentrations were greater in pigs fed diets containing RSpo (P = 0.03), while pigs fed diets containing FAM exhibited reduced total VFA concentrations (P = 0.11). The results indicate that supplementing diets with digestively resistant but fermentable fibers, short- and medium-chain fatty acids, or antibiotics do not have a consistent effect, positive or negative, on markers of intestinal integrity or barrier function, intestinal VFA patterns, ATTD of energy and nutrients, or on pig performance.

Early-Life Intervention of Lactoferrin and Probiotic in Suckling Piglets: Effects on Immunoglobulins, Intestinal Integrity, and Neonatal Mortality.

The aim of this study was to determine the effects of early-life bovine lactoferrin and host specific probiotic interventions on growth performance, mortality, and concentrations of immunoglobulin A and immunoglobulin G and transforming growth factor beta 1 (a marker of intestinal integrity) in serum of neonatal piglets. A total of eight piglet litters from parity matched sows were randomly divided into four groups and assigned to one of the four interventions: control (sterile normal saline), bovine lactoferrin (100mg bovine lactoferrin), probiotic (1 × 109 colony forming unit (cfu) of swine origin Pediococcus acidilactici FT28 probiotic), and bovine lactoferrin + probiotic (100mg bovine lactoferrin and 1 × 109CFU of P. acidilactici FT28 probiotic). All the interventions were given once daily through oral route for first 7days of life. The average daily gain (p = 0.0004) and weaning weight (p < 0.0001) were significantly improved in the probiotic group. The piglet survivability was significantly higher in bovine lactoferrin and probiotic groups than control group in Log-rank (Mantel-Cox) test. The concentrations of immunoglobulin A on day 21 in bovine lactoferrin, probiotic, and bovine lactoferrin + probiotic groups increased significantly (p < 0.05). Immunoglobulin G concentrations on day 7 and 15 in bovine lactoferrin and bovine lactoferrin + probiotic groups and on day 15 in probiotic group were significantly (p < 0.05) elevated, whereas, the concentration of transforming growth factor-β1 was significantly (p < 0.05) increased from day 7 to 21 in all the supplemented groups. In conclusion, the early-life bovine lactoferrin and P. acidilactici FT28 probiotic interventions reduced the mortality in the suckling piglets by promoting the systemic immunity and enhancing the intestinal integrity.

Compromised intestinal integrity in older adults during daily activities: a pilot study

BackgroundMalnutrition is a common and significant problem in older adults. Insight into factors underlying malnutrition is needed to develop strategies that can improve the nutritional status. Compromised intestinal integrity caused by gut wall hypoperfusion due to atherosclerosis of the mesenteric arteries in the aging gastrointestinal tract may adversely affect nutrient uptake. The presence of compromised intestinal integrity in older adults is not known. The aim of this study is to provide a proof-of-concept that intestinal integrity is compromised in older adults during daily activities.MethodsAdults aged ≥75 years living independently without previous gastrointestinal disease or abdominal surgery were asked to complete a standardized walking test and to consume a standardized meal directly afterwards to challenge the mesenteric blood flow. Intestinal fatty acid-binding protein (I-FABP) was measured as a plasma marker of intestinal integrity, in blood samples collected before (baseline) and after the walking test, directly after the meal, and every 15 min thereafter to 75 min postprandially.ResultsThirty-four participants (median age 81 years; 56% female) were included. Of the participants, 18% were malnourished (PG-SGA score ≥ 4), and 32% were at risk of malnutrition (PG-SGA score, 2 or 3). An I-FABP increase of ≥50% from baseline was considered a meaningful loss of intestinal integrity and was observed in 12 participants (35%; 8 females; median age 80 years). No significant differences were observed in either baseline characteristics, walking test scores, or calorie/macronutrient intake between the groups with and without a ≥ 50% I-FABP peak.ConclusionThis study is first to indicate that intestinal integrity is compromised during daily activities in a considerable part of older adults living independently.

Cold Renal Perfusion During Simulation of Juxtarenal Aortic Aneurysm Repair Reduces Systemic Oxidative Stress and Sigmoid Damage in Rats

Juxtarenal aortic surgery induces renal ischaemia reperfusion, which contributes to systemic inflammatory tissue injury and remote organ damage. Renal cooling during suprarenal cross clamping has been shown to reduce renal damage. It is hypothesised that renal cooling during suprarenal cross clamping also has systemic effects and could decrease damage to other organs, like the sigmoid colon. Open juxtarenal aortic aneurysm repair was simulated in 28 male Wistar rats with suprarenal cross clamping for 45 min, followed by 20 min of infrarenal aortic clamping. Four groups were created: sham, no, warm (37 °C saline), and cold (4 °C saline) renal perfusion during suprarenal cross clamping. Primary outcomes were renal damage and sigmoid damage. To assess renal damage, procedure completion serum creatinine rises were measured. Peri-operative microcirculatory flow ratios were determined in the sigmoid using laser Doppler flux. Semi-quantitative immunofluorescence microscopy was used to measure alterations in systemic inflammation parameters, including reactive oxygen species (ROS) production in circulating leukocytes and leukocyte infiltration in the sigmoid. Sigmoid damage was assessed using digestive enzyme (intestinal fatty acid binding protein - I-FABP) leakage, a marker of intestinal integrity. Suprarenal cross clamping caused deterioration of all systemic parameters. Only cold renal perfusion protected against serum creatinine rise: 0.45 mg/dL without renal perfusion, 0.33 mg/dL, and 0.14 mg/dL (p = .009) with warm and cold perfusion, respectively. Microcirculation in the sigmoid was attenuated with warm (p = .002) and cold renal perfusion (p = .002). A smaller increase of ROS production (p = .034) was seen only after cold perfusion, while leukocyte infiltration in the sigmoid colon decreased after warm (p = .006) and cold perfusion (p = .018). Finally, digestive enzyme leakage increased more without (1.5AU) than with warm (1.3AU; p = .007) and cold renal perfusion (1.2AU; p = .002). Renal ischaemia/reperfusion injury after suprarenal cross clamping decreased microcirculatory flow, increased systemic ROS production, leukocyte infiltration, and I-FABP leakage in the sigmoid colon. Cold renal perfusion was superior to warm perfusion and reduced renal damage and had beneficial systemic effects, reducing sigmoid damage in this experimental study.

Cold Renal Perfusion During Simulation of Juxtarenal Aortic Aneurysm Repair Reduces Systemic Oxidative Stress and Sigmoid Damage in Rats

Juxtarenal aortic surgery induces renal ischaemia reperfusion, which contributes to systemic inflammatory tissue injury and remote organ damage. Renal cooling during suprarenal cross clamping has been shown to reduce renal damage. It is hypothesised that renal cooling during suprarenal cross clamping also has systemic effects and could decrease damage to other organs, like the sigmoid colon. Open juxtarenal aortic aneurysm repair was simulated in 28 male Wistar rats with suprarenal cross clamping for 45min, followed by 20min of infrarenal aortic clamping. Four groups were created: sham, no, warm (37°C saline), and cold (4°C saline) renal perfusion during suprarenal cross clamping. Primary outcomes were renal damage and sigmoid damage. To assess renal damage, procedure completion serum creatinine rises were measured. Peri-operative microcirculatory flow ratios were determined in the sigmoid using laser Doppler flux. Semi-quantitative immunofluorescence microscopy was used to measure alterations in systemic inflammation parameters, including reactive oxygen species (ROS) production in circulating leukocytes and leukocyte infiltration in the sigmoid. Sigmoid damage was assessed using digestive enzyme (intestinal fatty acid binding protein - I-FABP) leakage, a marker of intestinal integrity. Suprarenal cross clamping caused deterioration of all systemic parameters. Only cold renal perfusion protected against serum creatinine rise: 0.45mg/dL without renal perfusion, 0.33mg/dL, and 0.14mg/dL (p=.009) with warm and cold perfusion, respectively. Microcirculation in the sigmoid was attenuated with warm (p=.002) and cold renal perfusion (p=.002). A smaller increase of ROS production (p=.034) was seen only after cold perfusion, while leukocyte infiltration in the sigmoid colon decreased after warm (p=.006) and cold perfusion (p=.018). Finally, digestive enzyme leakage increased more without (1.5AU) than with warm (1.3AU; p=.007) and cold renal perfusion (1.2AU; p=.002). Renal ischaemia/reperfusion injury after suprarenal cross clamping decreased microcirculatory flow, increased systemic ROS production, leukocyte infiltration, and I-FABP leakage in the sigmoid colon. Cold renal perfusion was superior to warm perfusion and reduced renal damage and had beneficial systemic effects, reducing sigmoid damage in this experimental study.

Advanced-age C57BL/6JRj mice do not develop obesity upon western-type diet exposure

ABSTRACT Obesity has become a global health-threat for every age group. It is well known that young mice (10-12 weeks of age) fed a western-type diet (WD) become obese and develop higher cholesterol levels and liver steatosis whereas insulin sensitivity is reduced. Less is known, however, about the effect of a WD on advanced-age mice. Therefore, 10 week-old (young) and 22 month-old (advanced-age), male C57BL/6JRj mice were kept on either a WD or a control diet (SFD) for 15 weeks. In contrast to young mice, advanced-age mice on WD did not show a higher body weight or adipose tissue (AT)-masses, suggesting a protection against diet-induced obesity. Furthermore, plasma adiponectin and leptin levels were not affected upon WD-feeding. A WD, however, did induce more hepatic lipid accumulation as well as increased hepatic expression of the macrophage marker F4/80, in advanced-age mice. There were no significant differences in mRNA levels of uncoupling protein-1 or F4/80 in brown AT (BAT) or of several intestinal integrity markers in colon suggesting that the protection against obesity is not due to excessive BAT or to impaired intestinal absorption of fat. Thus, advanced-age mice, in contrast to their younger counterparts, appeared to be protected against diet-induced obesity.

Plasma citrulline as a marker of intestinal function in neonates with feeding intolerance

Background Neonatal feeding intolerance may be the presentation of many diseases. Response to enteral feeding depends on enterocyte mass and function. Objective The aim was to assess the diagnostic and prognostic role of plasma citrulline level as a noninvasive marker in neonatal feeding intolerance. Patients and methods Thirty-nine neonates from the neonatal intensive care were classified into two groups: the patients’ group which included 26 neonates with different diagnosis, all of them had enteral feeding intolerance and the control group which included 26 neonates of similar gestational age and birth weight with no feeding intolerance. Patients with significant renal insufficiency or suspected urea cycle defect were excluded. This is a hybrid study. It was carried out in two phase. Phase 1: the case–control study in which we measured plasma citrulline in the patients’ and control group at the start of the study; and phase 2 the cohort study in which follow-up of plasma citrulline was done in patients at the time of diagnosis of feeding intolerance, when they started feeding, and when they reached 50% of their requirements. Results Plasma citrulline level at day 1 of presentation was significantly lower in the patients’ group than in the control group. In the absence of intestinal injury, plasma citrulline level increased significantly with the increase in gestational age, but once intestinal injury for any cause occurred, plasma citrulline level was no more age dependent. With more oral feeding tolerance, the plasma citrulline level increased significantly. Conclusion Plasma citrulline level is a very good noninvasive marker of intestinal integrity; it can assess the readiness for enteral feeding and it is not disease specific (whether medical or surgical conditions).

FRI-301 - MAIT cell dysfunctions correlate with markers of intestinal integrity in ALD patients

FRI-301 - MAIT cell dysfunctions correlate with markers of intestinal integrity in ALD patients

Adaptation of exercise-induced stress in well-trained healthy young men.

What is the central question of this study? Exercise is known to induce stress-related physiological responses, such as changes in intestinal barrier function. Our aim was to determine the test-retest repeatability of these responses in well-trained individuals. What is the main finding and its importance? Responses to strenuous exercise, as indicated by stress-related markers such as intestinal integrity markers and myokines, showed high test-retest variation. Even in well-trained young men an adapted response is seen after a single repetition after 1 week. This finding has implications for the design of studies aimed at evaluating physiological responses to exercise. Strenuous exercise induces different stress-related physiological changes, potentially including changes in intestinal barrier function. In the Protégé Study (ISRCTN14236739; www.isrctn.com), we determined the test-retest repeatability in responses to exercise in well-trained individuals. Eleven well-trained men (27±4 years old) completed an exercise protocol that consisted of intensive cycling intervals, followed by an overnight fast and an additional 90min cycling phase at 50% of maximal workload the next morning. The day before (rest), and immediately after the exercise protocol (exercise) a lactulose and rhamnose solution was ingested. Markers of energy metabolism, lactulose-to-rhamnose ratio, several cytokines and potential stress-related markers were measured at rest and during exercise. In addition, untargeted urine metabolite profiles were obtained. The complete procedure (Test) was repeated 1week later (Retest) to assess repeatability. Metabolic effect parameters with regard to energy metabolism and urine metabolomics were similar for both the Test and Retest period, underlining comparable exercise load. Following exercise, intestinal permeability (1h plasma lactulose-to-rhamnose ratio) and the serum interleukin-6, interleukin-10, fibroblast growth factor-21 and muscle creatine kinase concentrations were significantly increased compared with rest only during the first test and not when the test was repeated. Responses to strenuous exercise in well-trained young men, as indicated by intestinal markers and myokines, show adaptation in Test-Retest outcome. This might be attributable to a carry-over effect of the defense mechanisms triggered during the Test. This finding has implications for the design of studies aimed at evaluating physiological responses to exercise.

Transmucosal passage of bacteria across rat intestinal epithelium in the Ussing chamber: effect of nutritional factors and bacterial virulence.

Transmucosal passage of bacteria across the intestine, the essential and prerequisite step for bacterial translocation, cannot be effectively studied using in vivo models of translocation. We have adapted the Ussing chamber into a fresh, sterile organ culture system that can facilitate the study of bacterial-epithelial interactions. Intestinal membranes were mounted in the Ussing chamber and perfused with a solution rich in putative mucosal micronutrients. The transmembrane potential difference was constantly monitored as a marker of intestinal integrity. Transmucosal passage of various bacteria across the normal intestinal epithelium was quantitated, and the mucosal membrane was examined by light and transmission electron microscopy. The addition of potassium cyanide to the mucosal perfusate resulted in an irreversible loss of potential difference. Oxygen deprivation also led to a precipitous drop in potential difference, but it was reversible with prompt reoxygenation. In contrast, intestinal membranes perfused with a solution consisting of Dulbecco's modified Eagle's medium + 20 mM glutamine maintained their potential difference for a sustained period (>180 min). Both the viability and structural integrity of the ileal intestinal membrane were maintained in culture ex vivo using this perfusate. Qualitative differences were observed in the mechanism of transmucosal passage of mild to moderately virulent bacteria such as Escherichia coli C-25 and Proteus mirabilis M-13, which pass through the intestinal epithelium without causing overt damage to the mucosa, and more virulent organisms such as Salmonella typhimurium, which cause extensive mucosal damage by light and transmission electron microscopy. The Ussing system should provide a useful model of intact organ culture for the study of the mechanisms of bacterial translocation and the pathogenesis of enteric infections.

Diamine oxidase as a marker of intestinal integrity in acute appendicitis.

In the operative treatment of appendicitis the so called negative appendectomy is an important issue because of its increased morbidity. From the hypothesis that the intestinal diamine oxidase activity is a suitable marker of mucosal integrity, the distribution pattern of the enzyme in appendices histologically classified as inflamed or not inflamed was studied. Histologically apparent inflammation of the appendix was connected with a significant reduction of diamine oxidase activity. The determination of this enzymic activity may be a simple and sensitive test for mucosal inflammation of the appendix even at a very early state. This could reduce the rate of negative appendectomies and influence thereby risk-cost-benefit calculations.