Acute psychological stress increases small intestinal permeability in humans. Peripheral CRH reproduces the effect of stress and DSCG blocks the effect of both stress and CRH, suggesting the involvement of mast cells. These findings provide new insight into the complex interplay between the central nervous system and GI function in man.

Objectives: To evaluate the diagnostic performance of seven rapid IgG/IgM tests and the Euroimmun IgA/ IgG ELISA for antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in COVID-19 patients. Methods: Specificity was evaluated in 103 samples collected before January 2020. Sensitivity and time to seropositivity was evaluated in 167 samples from 94 patients with COVID-19 confirmed with RT-PCR on nasopharyngeal swab. Results: Specificity (confidence interval) of lateral flow assays (LFAs) was 91.3% (84.0e95.5) for IgM, 90.3% (82.9e94.8) for IgG, and 85.4% (77.2e91.1) for the combination IgM OR IgG. Specificity of the ELISA was 96.1% (90.1e98.8) for IgG and only 73.8% (64.5e81.4) for IgA. Sensitivity 14e25 days after the onset of symptoms was between 92.1% (78.5e98.0) and 100% (95.7e100) for IgG LFA compared to 89.5% (75.3e96.4) for IgG ELISA. Positivity of IgM OR IgG for LFA resulted in a decrease in specificity compared to IgG alone without a gain in diagnostic performance, except for VivaDiag. The results for IgM varied significantly between the LFAs with an average overall agreement of only 70% compared to 89% for IgG. The average dynamic trend to seropositivity for IgM was not shorter than for IgG. At the time of hospital admission the sensitivity of LFA was <60%. Conclusions: Sensitivity for the detection of IgG antibodies 14e25 days after the onset of symptoms was 92.1% for all seven LFAs compared to 89.5% for the IgG ELISA. The results for IgM varied significantly, and including IgM antibodies in addition to IgG for the interpretation of LFAs did not improve the diagnostic performance.

Objectives The aim was to determine the antibody response against SARS-CoV-2 spike protein and nucleoprotein using four automated immunoassays and three ELISAs for the detection of total Ig antibodies (Roche) or IgG (Abbott, Diasorin, Snibe, Euroimmun, Mikrogen) in COVID-19 patients. Methods Sensitivity and dynamic trend to seropositivity were evaluated in 233 samples from 114 patients with moderate, severe or critical COVID-19 confirmed with PCR on nasopharyngeal swab. Specificity was evaluated in 113 samples collected before January 2020, including 24 samples from patients with non-SARS coronavirus infection. Results Sensitivity for all assays was 100% (95% confidence interval 83.7–100) 3 weeks after onset of symptoms. Specificity varied between 94.7% (88.7–97.8) and 100% (96.1–100). Calculated at the cut-offs that corresponded to a specificity of 95% and 97.5%, Roche had the highest sensitivity (85.0% (79.8–89.0) and 81.1% (76.6–85.7), p < 0.05 except vs. Abbott). Seroconversion occurred on average 2 days earlier for Roche total Ig anti-N and the three IgG anti-N assays (Abbott, Mikrogen, Euroimmun) than for the two IgG anti-S assays (Diasorin, Euroimmun) (≥50% seroconversion day 9–10 vs. day 11–12 and p < 0.05 for percent seropositive patients day 9–10 to 17–18). There was no significant difference in the IgG antibody time to seroconversion between critical and non-critical patients. Discussion Seroconversion occurred within 3 weeks after onset of symptoms with all assays and on average 2 days earlier for assays detecting IgG or total Ig anti-N than for IgG anti-S. The specificity of assays detecting anti-N was comparable to anti-S and excellent in a challenging control population.

Wheat bran extract (WBE) is a food-grade soluble fibre preparation that is highly enriched in arabinoxylan oligosaccharides. In this placebo-controlled cross-over human intervention trial, tolerance and effects on colonic protein and carbohydrate fermentation were studied. After a 1-week run-in period, sixty-three healthy adult volunteers consumed 3, 10 and 0 g WBE/d for 3 weeks in a random order, with 2 weeks' washout between each treatment period. Fasting blood samples were collected at the end of the run-in period and at the end of each treatment period for analysis of haematological and clinical chemistry parameters. Additionally, subjects collected a stool sample for analysis of microbiota, SCFA and pH. A urine sample, collected over 48 h, was used for analysis ofp-cresol and phenol content. Finally, the subjects completed questionnaires scoring occurrence frequency and distress severity of eighteen gastrointestinal symptoms. Urinaryp-cresol excretion was significantly decreased after WBE consumption at 10 g/d. Faecal bifidobacteria levels were significantly increased after daily intake of 10 g WBE. Additionally, WBE intake at 10 g/d increased faecal SCFA concentrations and lowered faecal pH, indicating increased colonic fermentation of WBE into desired metabolites. At 10 g/d, WBE caused a mild increase in flatulence occurrence frequency and distress severity and a tendency for a mild decrease in constipation occurrence frequency. In conclusion, WBE is well tolerated at doses up to 10 g/d in healthy adults volunteers. Intake of 10 g WBE/d exerts beneficial effects on gut health parameters.

Short chain fatty acids (SCFA), including acetate, propionate, and butyrate, are produced during bacterial fermentation of undigested carbohydrates in the human colon. In this study, we applied a stable-isotope dilution method to quantify the in vivo colonic production of SCFA in healthy humans after consumption of inulin. Twelve healthy subjects performed a test day during which a primed continuous intravenous infusion with [1-13C]acetate, [1-13C]propionate and [1-13C]butyrate (12, 1.2 and 0.6 μmol·kg−1·min−1, respectively) was applied. They consumed 15 g of inulin with a standard breakfast. Breath and blood samples were collected at regular times during the day over a 12 h period. The endogenous rate of appearance of acetate, propionate, and butyrate was 13.3 ± 4.8, 0.27 ± 0.09, and 0.28 ± 0.12 μmol·kg−1·min−1, respectively. Colonic inulin fermentation was estimated to be 137 ± 75 mmol acetate, 11 ± 9 mmol propionate, and 20 ± 17 mmol butyrate over 12 h, assuming that 40%, 10%, and 5% of colonic derived acetate, propionate, and butyrate enter the systemic circulation. In conclusion, inulin is mainly fermented into acetate and, to lesser extents, into butyrate and propionate. Stable isotope technology allows quantifying the production of the three main SCFA in vivo and proved to be a practical tool to investigate the extent and pattern of SCFA production.

Objective: To investigate the influence of different pre-and probiotics on faecal b-glucuronidase and b-glucosidase activity, as one of the claimed beneficial effects of pre-and probiotics is the hypothesis that these substrates are able to reduce the production of toxic and carcinogenic metabolites by suppressing specific enzyme activities in the colon. Setting: Department of Gastrointestinal Research, University Hospital Gasthuisberg, KU Leuven, Belgium. Design and subjects: The effect was evaluated in a randomized, crossover study in 53 healthy volunteers who were randomly assigned to one of five treatment groups. Interventions: At the start and after a 4-week treatment period, the healthy volunteers collected faeces during 72 h. Lactulose and oligofructose-enriched inulin (OF-IN) were chosen as prebiotics, whereas Lactobacillus casei Shirota, Bifidobacterium breve and Saccharomyces boulardii were selected as probiotics. Two synbiotic combinations were evaluated as well. The enzyme activity was assessed spectrophotometricly. Results: Lactulose and OF-IN significantly decreased b-glucuronidase activity, whereas a tendency to a decreased bglucuronidase activity was observed after L. casei Shirota and B. breve intake. To the contrary, B. breve increased b-glucosidase levels. Supplementation with the synbiotic did not appear to be more beneficial than either compound alone. No influence of S. boulardii was noted. Conclusions: Administration of lactulose, OF-IN, L. casei Shirota or B. breve resulted in a decrease of the b-glucuronidase activity, which is considered beneficial for the host.

BackgroundImpaired intestinal barrier function, low-grade inflammation and altered neuronal control are reported in functional gastrointestinal disorders. However, the sequence of and causal relation between these events is unclear, necessitating a spontaneous animal model. The aim of this study was to describe the natural history of intestinal permeability, mucosal and neuromuscular inflammation and nitrergic motor neuron function during the lifetime of the BioBreeding (BB) rat.MethodsNormoglycemic BB-diabetes prone (DP) and control rats were sacrificed at different ages and jejunum was harvested to characterize intestinal permeability, inflammation and neuromuscular function.ResultsBoth structural and functional evidence of increased intestinal permeability was found in young BB-DP rats from the age of 50 days. In older animals, starting in the mucosa from 70 days and in half of the animals also in the muscularis propria from 110 days, an inflammatory reaction, characterized by an influx of polymorphonuclear cells and higher myeloperoxidase activity, was observed. Finally, in animals older than 110 days, coinciding with a myenteric ganglionitis, a loss of nitrergic neurons and motor function was demonstrated.ConclusionIn the BB-rat, mucosal inflammatory cell infiltration is preceded by intestinal barrier dysfunction and followed by myenteric ganglionitis and loss of nitrergic function. This sequence supports a primary role for impaired barrier function and provides an insightful model for the pathogenesis of functional gastrointestinal disorders.

Objective The study sought to describe the development, implementation, and requirements of laboratory information system (LIS) functionality to manage test ordering, registration, sample flow, and result reporting during the coronavirus disease 2019 (COVID-19) pandemic. Materials and Methods Our large (&gt;12 000 000 tests/y) academic hospital laboratory is the Belgian National Reference Center for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing. We have performed a moving total of &gt;25 000 SARS-CoV-2 polymerase chain reaction tests in parallel to standard routine testing since the start of the outbreak. A LIS implementation team dedicated to develop tools to remove the bottlenecks, primarily situated in the pre- and postanalytical phases, was established early in the crisis. Results We outline the design, implementation, and requirements of LIS functionality related to managing increased test demand during the COVID-19 crisis, including tools for test ordering, standardized order sets integrated into a computerized provider order entry module, notifications on shipping requirements, automated triaging based on digital metadata forms, and the establishment of databases with contact details of other laboratories and primary care physicians to enable automated reporting. We also describe our approach to data mining and reporting of actionable daily summary statistics to governing bodies and other policymakers. Conclusions Rapidly developed, agile extendable LIS functionality and its meaningful use alleviates the administrative burden on laboratory personnel and improves turnaround time of SARS-CoV-2 testing. It will be important to maintain an environment that is conducive for the rapid adoption of meaningful LIS tools after the COVID-19 crisis.