High prevalence and functional effects of serum antineuronal antibodies in patients with gastrointestinal disorders.

BACKGROUND: Antineuronal antibodies can be associated with both gastrointestinal (GI) and brain disorders. For example, antibodies against the potassium channel subunit dipeptidyl-peptidase-like protein-6 (DPPX) bind to neurons in the central nervous system (CNS) and myenteric plexus and cause encephalitis, commonly preceded by severe unspecific GI symptoms. We therefore investigated the prevalence of antineuronal antibodies indicative of treatable autoimmune CNS etiologies in GI patients. METHODS: Serum samples of 107 patients (Crohn's disease n = 42, ulcerative colitis n = 16, irritable bowel syndrome n = 13, others n = 36) and 44 healthy controls were screened for anti-DPPX and further antineuronal antibodies using immunofluorescence on rat brain and intestine and cell-based assays. Functional effects of high-titer reactive sera were assessed in organ bath and Ussing chamber experiments and compared to non-reactive patient sera. KEY RESULTS: Twenty-one of 107 patients (19.6%) had antibodies against the enteric nervous system, and 22 (20.6%) had anti-CNS antibodies, thus significantly exceeding frequencies in healthy controls (4.5% each). Screening on cell-based assays excluded established antienteric antibodies. Antibody-positive sera were not associated with motility effects in organ bath experiments. However, they induced significant, tetrodotoxin (TTX)-insensitive secretion in Ussing chambers compared to antibody-negative sera. CONCLUSIONS & INFERENCES: Antineuronal antibodies were significantly more frequent in GI patients and associated with functional effects on bowel secretion. Future studies will determine whether such antibodies indicate patients who might benefit from additional antibody-directed therapies. However, well-characterized encephalitis-related autoantibodies such as against DPPX were not detected, underlining their rarity in routine cohorts.

Campylobacter jejuni impairs sodium transport and epithelial barrier function via cytokine release in human colon.

This corrects the article DOI: 10.1038/mi.2017.66.

Tricellulin is regulated via interleukin-13-receptor α2, affects macromolecule uptake, and is decreased in ulcerative colitis.

In the two inflammatory bowel diseases, ulcerative colitis (UC) and Crohn's disease (CD), altered expression of tight junction (TJ) proteins leads to an impaired epithelial barrier including increased uptake of luminal antigens supporting the inflammation. Here, we focused on regulation of tricellulin (Tric), a protein of the tricellular TJ essential for the barrier against macromolecules, and hypothesized a role in paracellular antigen uptake. We report that Tric is downregulated in UC, but not in CD, and that its reduction increases the passage of macromolecules. Using a novel visualization method, passage sites were identified at TJ regions usually sealed by Tric. We show that interleukin-13 (IL-13), beyond its known effect on claudin-2, downregulates Tric expression. These two effects of IL-13 are regulated by different signaling pathways: The IL-13 receptor α1 upregulates claudin-2, whereas IL-13 receptor α2 downregulates Tric. We suggest to target the α2 receptor in future developments of therapeutical IL-13-based biologicals.

Campylobacter jejuni impairs sodium transport and epithelial barrier function via cytokine release in human colon.

Campylobacter jejuni is the most prevalent cause of foodborne bacterial enteritis worldwide. Patients present with diarrhea and immune responses lead to complications like arthritis and irritable bowel syndrome. Although studies exist in animal and cell models, we aimed at a functional and structural characterization of intestinal dysfunction and the involved regulatory mechanisms in human colon. First, in patients' colonic biopsies, sodium malabsorption was identified as an important diarrheal mechanism resulting from hampered epithelial ion transport via impaired epithelial sodium channel (ENaC) ß- and γ-subunit. In addition, barrier dysfunction from disrupted epithelial tight junction proteins (claudin-1, -3, -4, -5, and -8), epithelial apoptosis, and appearance of lesions was detected, which cause leak-flux diarrhea and can perpetuate immune responses. Importantly, these effects in human biopsies either represent direct action of Campylobacter jejuni (ENaC impairment) or are caused by proinflammatory signaling (barrier dysfunction). This was revealed by regulator analysis from RNA-sequencing (cytometric bead array-checked) and confirmed in cell models, which identified interferon-γ, TNFα, IL-13, and IL-1ß. Finally, bioinformatics' predictions yielded additional information on protective influences like vitamin D, which was confirmed in cell models. Thus, these are candidates for intervention strategies against C. jejuni infection and post-infectious sequelae, which result from the permissive barrier defect along the leaky gut.

Diffuse gastric cancer with peritoneal carcinomatosis can mimic Crohn's disease.

In some cases the diagnosis of gastric cancer is difficult and the endoscopic presentation may be misleading. Diffuse type gastric carcinoma with peritoneal metastasis may present primarily with abdominal pain, colonic infiltration and/or diarrhea, thus other differential diagnoses like Crohn's disease (CD) may be considered at first. Therefore intensive diagnostic work-up is important. We report two cases of gastric cancer with ascites due to peritoneal carcinomatosis who were first diagnosed as CD. The patients were hospitalized in different institutions for weight loss, abdominal pain and nausea. The first colonoscopy, upper endoscopy with multiple biopsies and ascites puncture were negative for malignant disease, but macroscopic lesions resembling CD were described. Both patients were released on a prednisolone-based treatment for suspected CD. They presented to our hospital for further evaluation due to persistent symptoms. Neither lower nor upper endoscopy were suggestive of CD and endoscopic ultrasound was suspicious of malignancy in one case. Histology was diagnostic and showed gastric infiltration by a poorly differentiated adenocarcinoma. Diffuse type gastric cancer (gastric linitis plastica) with peritoneal metastasis may mimic certain clinical, endoscopic and CT imaging features of CD. Repeated biopsies and endoscopic investigations are often necessary to confirm a malignant process, especially in case of an inconclusive clinical and endoscopic picture. Endoscopic ultrasound may be useful to evaluate the risk of malignancy in patients with macroscopic suspicion of malignancy and negative biopsies.

[Neuroendocrine colorectal tumors. Surgical and endoscopic treatment]. / Neuroendokrine kolorektale Tumoren. Chirurgische und endoskopische Therapieverfahren.

The incidence of colorectal neuroendocrine tumors (NETs) is rising in developed countries primarily as a result of increased incidental detection by endoscopy and probably also due to a more adequate diagnosis according to the WHO classification. Less than 1% of colorectal NETs produce serotonin so that such tumors are practically never associated with a hormonal carcinoid syndrome. An exact clinico-pathological staging is of paramount importance for the therapeutic strategy and comprises the classification of the tumor type (well or poorly differentiated) and the assessment of established prognostic risk factors (depth of infiltration, vascular invasion, lymph node and distant metastases). Poorly differentiated colorectal NETs often present in an advanced, metastatic state, where surgical therapy is basically palliative. Well-differentiated tumors larger than 2 cm have a high risk of metastatic spread and should be treated as adenocarcinomas by radical oncological surgical resection. This applies to the majority of colon NETs. Tumors smaller than 1 cm, mainly locacted in the rectum, only rarely metastasize and are usually accessible for endoscopic treatment or transanal local surgery. Tumors between 1 and 2 cm in size have an uncertain prognosis and additional risk factors and co-morbidities of the patient have to be considered for a suitable, multidisciplinary therapeutic decision.

Diagnostic value of confocal endomicroscopy in celiac disease.

BACKGROUND: Improved endoscopic screening with targeted biopsies might enhance diagnostic yield in celiac disease. Confocal endomicroscopy (CEM) allows high-resolution in vivo histological analysis. We compared the endomicroscopic findings during ongoing endoscopy with the histological findings graded according to the Marsh classification. METHODS: Twenty-four patients with celiac disease and six patients with celiac disease that was refractory on a gluten-free diet were examined using CEM. The duodenal mucosa was evaluated by CEM and by conventional histological analysis in respect of villous atrophy, crypt hyperplasia, and increased numbers of intraepithelial lymphocytes (IELs > 40 / 100 enterocytes). The CEM results were assessed as to sensitivity, specificity, and interobserver variability. A Marsh classification score determined by CEM was compared to that obtained by histology. Thirty patients undergoing routine upper gastrointestinal endoscopy were used as controls. RESULTS: Conventional histology showed villous atrophy and crypt hyperplasia in 23 and increased numbers of IELs in 27 of the 30 patients with celiac disease. With CEM, villous atrophy, crypt hyperplasia, and increased IELs were respectively identified in 17, 12, and 22 of the 30 patients. The agreement of the findings on CEM with those of conventional histology was good in relation to villous atrophy (sensitivity 74 %) and increased numbers of IELs (sensitivity 81 %), but inadequate in relation to crypt hyperplasia (sensitivity 52 %). The kappa values for determination of interobserver variability were 0.90 for villous atrophy, 1.00 for crypt hyperplasia, and 0.84 for IEL detection. In the 30 control patients, normal duodenal architecture was found by both histology and endomicroscopy, indicating an overall specificity of 100 %. CONCLUSION: The assessment of duodenal histology by CEM in patients with celiac disease is sensitive and specific in determining increased numbers of IELs and villous atrophy, but insufficient in respect of crypt hyperplasia. For routine use of CEM in patients with celiac disease, the technique would need to be improved.

Confocal neurolasermicroscopy in human brain - perspectives for neurosurgery on a cellular level (including additional comments to this article).

BACKGROUND: During neurosurgery intraoperative imaging of vital neural structures on a cellular level would facilitate the development of new strategies for diagnosis and treatment. In vivo imaging would permit the detection of the tumour centre and infiltration zone. With targeted biopsies the lesion of interest could be determined before performing the biopsy, facilitating the final pathological diagnosis. In this study we present confocal neurolasermicroscopy as a new method in neurosurgery. METHODS: A miniaturised confocal neurolasermicroscope (NLM) was used ex vivo immediately after tumour resection of glioblastoma multiforme (GBM). NLM was performed with subcellular magnification up to a tissue depth of 100 microm. NLM images were compared to conventional histological images of the same tumour. RESULTS: The application of the method in nine patients allowed adequate diagnosis of a malignant glioma fulfilling the WHO criteria when compared to conventional histology. In one patient with glioblastoma multiforme NLM allowed the correct diagnosis of GBM to be made, demonstrating the high mitotic rate and cell pleomorphy of the tumour cells. Additional characteristics such as pleomorphic cells, mitotic figures, fibrillary matrix and the distinction between tumour centre and infiltration zone could be shown. CONCLUSIONS: NLM is a tool which could be adapted for neurosurgical intraoperative applications with the potential to diagnose tumours and recognise the tumour centre and infiltration zone in vivo. Further applications of NLM to characterise subcellular structures and vascular architecture are possible.

In vivo diagnosis of acute intestinal graft-versus-host disease by confocal endomicroscopy.

BACKGROUND AND STUDY AIMS: Conventional histology with hematoxylin and eosin (H&E) staining is the accepted standard for diagnosing acute intestinal graft-versus-host disease (GvHD). Confocal endomicroscopy (CEM) is a noninvasive method that allows in vivo histology to be performed during endoscopy. The aim of this study was to evaluate CEM for the diagnosis of acute intestinal GvHD. PATIENTS AND METHODS: This observational pilot study conducted between September 2006 and August 2008 included patients with acute diarrhea after stem cell transplantation, infectious diarrhea, or active ulcerative colitis. CEM (EC-3870CIFK, Pentax, Tokyo, Japan) was performed after intravenous injection of fluorescein 10% and topical application of acriflavine 0.05%. RESULTS: A total of 35 patients with acute diarrhea after stem cell transplantation were examined. In 16 patients, CEM and histology showed no evidence of GvHD. In 14/19 patients with histologically confirmed GvHD, the diagnosis could already be established by CEM during ongoing endoscopy. In GvHD grade IV, near complete destruction of the colonic crypts ("flat mucosa") was visible. Control patients with infectious colitis (N = 15) or ulcerative colitis (N = 15) displayed inflammatory changes but no evidence of GvHD. Altogether, sensitivity of CEM was 74% and specificity was 100 %. CONCLUSIONS: CEM improves rapid diagnosis of acute intestinal GvHD with high accuracy while performing endoscopy. Platelet transfusions and unnecessary biopsy acquisition can be avoided once acute intestinal GvHD has been diagnosed in vivo.

Occurrence of adenomas in the pouch and small intestine of FAP patients after proctocolectomy with ileoanal pouch construction.

PURPOSE: Proctocolectomy with ileoanal pouch construction is the standard therapy for patients with familial adenomatous polyposis coli (FAP) to prevent the genesis of colorectal carcinomas. In our patient population, we observed the postoperative development of adenomas not only in the pouch but also in the remaining small intestine. The exact incidence of these ileal polyps is still unknown, since the diagnostic possibilities of examining the small intestine are limited. METHODS: We performed wireless capsule endoscopy (CE) in patients who developed postoperative pouch adenomas (PA) to record the simultaneous occurrence of small bowel adenomas and PA. We operated on 46 patients with FAP (m:f 17:10, age 33 +/- 9 years). Thirty-five patients underwent proctocolectomy with ileoanal pouch creation. Pouch endoscopy was performed in regular intervals at 3 months and then annually after proctocolectomy. Capsule endoscopy was additionally carried out in all patients with PA. RESULTS: Ileal PA occurred in 22.8% (n = 8) of the patients with proctocolectomy (n = 35) after a mean of 5 years after surgery. Eight PA patients (all with PA) also had adenomas in the small intestine diagnosed by CE. CONCLUSIONS: Since jejunal and ileal adenomas occur in all patients with PA, we recommend regular follow-up examinations, which include pouch endoscopy at 3 months and annually after surgery in the presence of PA after proctocolectomy and pouch creation. On the basis of our observations, we recommend adding CE or double-balloon enteroscopy to the follow-up examination.

Downregulation of epithelial apoptosis and barrier repair in active Crohn's disease by tumour necrosis factor alpha antibody treatment.

BACKGROUND AND AIMS: Barrier dysfunction is an important feature contributing to inflammation and diarrhoea in Crohn's disease (CD). Recently, tumour necrosis factor alpha (TNF-alpha) antibodies were recognised as effective in steroid refractory CD. The aim of this study was to characterise the effects of this therapy on the epithelial barrier. PATIENTS AND METHODS: Forceps biopsies were obtained from the sigmoid colon before and 14 days after TNF-alpha antibody therapy in 11 patients treated for chronic active CD (Crohn's disease activity index >150). Epithelial apoptoses were measured after terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labelling (TUNEL) and 4',6-diamidino-2-phenylindole staining. Epithelial resistance was determined by alternating current impedance analysis in miniaturised Ussing chambers. Occludin, claudin 1, and claudin 4 expression was quantified in immunoblots. RESULTS: The epithelial apoptotic ratio was 2.1 (0.2)% in controls and increased to 5.3 (1.0)% in CD. TNF-alpha antibody therapy decreased the apoptotic ratio to 2.9 (1.0)% (normalised in 10 of 11 patients). In parallel, epithelial resistance was lower in CD than in controls (24 (3) v 42 (3) Omegaxcm(2)) and improved to 34 (3) Omegaxcm(2) after therapy. Occludin, claudin 1, and claudin 4 were not affected by TNF-alpha antibody therapy. In support of a functional role of epithelial apoptoses in CD, a similar decrease in resistance of -40% was observed when the apoptotic rate was selectively upregulated from 2.6% to 5.4% with camptothecin in HT-29/B6 cells. CONCLUSIONS: Epithelial apoptoses were upregulated in the colon in CD and restored to normal in 10 of 11 patients by TNF-alpha antibody therapy. This is the structural correlate of epithelial barrier dysfunction measured as epithelial resistance while expression of tight junction proteins did not contribute to this therapeutic effect.

Excitation energy transport and trapping in concentrated solid solutions of flavomononucleotide.

Excitation energy transport and trapping is studied for monomer-fluorescent dimer system of flavomononucleotide (FMN) in polyvinyl alcohol films (PVA). It is shown that the theory neglecting reverse energy transfer (RET) from dimers to monomers does not allow for the explanation of concentration quenching and concentration depolarization results presented herein. Much better agreement has been obtained using generalized energy transport theory in which fluorescent dimers are treated as imperfect traps for excitation energy. Such parameters like the dimer quantum yield and its emission anisotropy are estimated.

Permeability of human HT-29/B6 colonic epithelium as a function of apoptosis.

1. The barrier function of colonic epithelia is challenged by apoptotic loss of enterocytes. In monolayers of human colonic HT-29/B6 cells, apoptosis induced by camptothecin was assessed by poly-(ADP-ribose)-polymerase (PARP) cleavage, histone ELISA and DNA-specific fluorochrome staining (with 4',6'-diamidino-2'-phenylindoladihydrochloride (DAPI)). Epithelial barrier function was studied in Ussing chambers by measuring transepithelial conductivity and unidirectional tracer fluxes. The ion permeability associated with single cell apoptoses was investigated with the conductance scanning technique. 2. The spontaneous rate of apoptotic cells was 3.5 +/- 0.3 % with an overall epithelial conductivity of 3.2 +/- 0.1 mS cm(-2). Camptothecin induced a time- and dose-dependent increase of apoptosis and permeability. With 20 microg ml(-1) of camptothecin for 48 h, apoptosis increased 4.1-fold to 14.3 +/- 1.5 % and the conductivity doubled to 6.4 +/- 1.0 mS cm(-2). 3. While 3H-mannitol flux increased 3.8-fold and 3H-lactulose flux increased 2.6-fold, the flux of 3H-polyethylene glycol 4000 remained unchanged. Hence, the higher permeability was limited to molecules < 4000 Da. 4. The local epithelial conductivity was higher at the sites of apoptosis than in non-apoptotic areas. With camptothecin the leaks associated with apoptosis became more numerous and more conductive, while in non-apoptotic areas the conductivity remained at control level. Hence, the camptothecin-induced increase in epithelial conductivity reflected the opening of apoptotic leaks and thus the results described, for the first time, epithelial permeability as a function of apoptosis only. 5. The conductivity of apoptotic leaks contributed 5.5 % to the epithelial conductivity of controls and 60 % to the conductivity of monolayers treated with 20 microg ml(-1) of camptothecin. Thus apoptosis increased the contribution of paracellular pathways to the overall epithelial permeability. Under control conditions the paracellular conductivity (G(para)) was smaller than the transcellular (G(trans)), but with 12 % apoptosis, G(para) exceeded G(trans). By definition, the epithelium became 'leaky'.

Patients with dyspepsia benefit from eradication of Helicobacter pylori if other organic causes for dyspepsia were carefully ruled out.

AIM: In order to investigate the potential of Helicobacter pylori (HP) to induce dyspepsia, we performed a randomized prospective study on the long-term effect of HP-eradication on symptoms of HP-positive dyspeptic patients in whom other organic causes for dyspepsia were carefully ruled out. PATIENTS: 201 patients referred to our endoscopy unit with dyspeptic symptoms for at least six months entered the study. Patients with previous peptic ulcer were excluded. METHODS: After endoscopy of the upper alimentary tract and 13C-urea breath test, patients with active peptic ulcer, hiatal hernia, macroscopic evidence for esophagitis and negative HP-status were excluded. The remaining patients underwent abdominal sonography, H2-exhalation test with lactose, and 24-h pH monitoring in order to exclude other organic causes for dyspepsia. In 20 patients, dyspepsia was assumed to be due to HP-gastritis. Patients received eradication therapy and were controlled as assessed by the 13C-urea breath test six weeks and six months after completion of the therapy. Dyspeptic symptoms were monitored by means of a validated symptom score. RESULTS: Out of 20 patients with HP-gastritis the first eradication treatment was successful in 13, while seven patients remained HP-positive after antibiotic treatment. Six months after completion of therapy the symptoms of HP-eradicated patients improved considerably (score values 17.4 +/- 1.5 and 10.2 +/- 0.8, respectively, p < 0.01) whereas symptoms of patients with persistent infection remained unchanged (21.1 +/- 1.7 and 20.4 +/- 1.5, n.s.) and only improved after successful retherapy (20.4 +/- 1.5 and 11.7 +/- 2.1, p < 0.05). In total, 17 of 20 patients (85%) improved after successful eradication. Also, neutrophil infiltration in the gastric mucosa correlated to both dyspeptic symptoms before therapy (r = 0.85) and the decrease in symptom score after HP-eradication (r = 0.61). In contrast, the symptoms of eight patients with gastroesophageal reflux disease were not improved after eradication (20.0 +/- 1.1 and 18.2 +/- 1.0, n.s.) CONCLUSIONS: HP-infection per se contributes to dyspepsia. 17 of 20 (85%) HP-positive dyspeptic patients improved after HP-eradication, when other potential organic causes for dyspepsia had been ruled out. However, many patients did not completely recover but the symptoms only partly decreased which parallels the persistence of part of the inflammatory infiltration in the gastric mucosa. This emphasizes the importance of HP-gastritis as an organic disease causing dyspeptic symptoms.

Apoptosis and intestinal barrier function.

The signal transduction pathways of the induction of apoptosis in the gastrointestinal tract have in part been discovered. However, almost nothing is known about the functional influence of apoptotic signals on intestinal barrier function. In this study the effect of camptothecin-induced apoptosis in HT-29/B6 monolayers and the influence of apoptosis on epithelial barrier function were characterized. We demonstrated that camptothecin causes a decrease of transepithelial resistance and an increase in fluxes of the paracellular marker [3H]mannitol. Camptothecin increased the apoptotic rate and the conductance of single-cell apoptosis as measured by the conductance scanning technique. We conclude that in our model of HT-29/B6 cells camptothecin is a potent inductor of apoptosis that causes significant barrier defects measured by the Ussing chamber technique and the conductance scanning technique. Based on these results we are able to investigate the effect of other cytokines--TGF-beta, for instance, and its role in apoptotic conditions.

Dual versus triple therapy: comparison of five antibiotic regimens for eradication of Helicobacter pylori in a prospective, randomized study.

We compared the efficacy of three dual and two triple therapies for eradication of Helicobacter pylori (HP), and evaluated the influence of smoking and omeprazole pretreatment on HP eradication. 220 patients with proven HP infection (histology and 13C-urea breath test [UBT]) were randomly allocated to one of the following regimes: BMT (bismuth subsalicylate 600 mg t. i. d. for 28 days, metronidazole 400 mg t. i. d. and tetracycline 500 mg q. i. d. for ten days). OA (omeprazole 40 mg o. d. and amoxicillin 750 mq q. i. d. for 14 days), OC (omeprazole 40 mg o. d. and clarithromycin 500 mg b. i. d. for 14 days), OT (omeprazole 40 mg o. d. and tetracycline 500 mg q. i. d. for 14 days), OMC (omeprazole 40 mg o. d., metroinidazole 400 mg t. i. d. and clarithromycin 250 mg b. i. d. for seven days). Eradication was defined as negative UBT six weeks after completion of the therapy. In an "all-patients-treated" ("per-protocol") analysis, the eradication rates were: BMT, 91% (93%); OA, 84% (90%); OC, 74% (74%); OT, 24% (24%); and OMC, 90% (93%). Smoking impaired the success of OA and OT (p < 0.05), but the efficacy of the triple regimens was not affected. Omeprazole pretreatment did not influence eradication rates. Thus, highest eradication rates were achieved with the two triple therapies tested. However, OA, given at a daily antibiotic dose of 3 g amoxicillin for 14 d, was also highly effective. After failure of triple therapy, OA was successful in seven of ten patients (70%). The efficacy of OC was lower than that of the triple therapies (p < 0.05). In conclusion, metronidazole- and clarithromycin-based triple therapies are highly effective first line therapies. OA, given at a dose of 3 g per day over 14 days, should be considered as a possible second line therapy, e.g. in retherapy after failed triple therapy.

Spectroscopic manifestations of flavomononucleotide dimers in polyvinyl alcohol films.

Absorption and fluorescence spectra of flavomononucleotide (FMN) in polyvinyl alcohol films (PVA) over a very wide concentration range are investigated. The dimerization constant as well as the pure monomer and dimer spectra are calculated and the structural parameters of FMN dimer are established. Excitation wavelength and temperature dependencies of FMN/PVA fluorescence spectra for different FMN concentrations were carried out. These measurements together with those of absorption reveal that dimers are imperfect traps for excitation energy and that the energy transfer can occur both in forward and in reverse direction. Moreover, it was shown that the observed temperature changes in fluorescence spectra may be qualitatively explained by the effect of inhomogeneous broadening of FMN energy levels and by the presence of fluorescent dimers.

13C-urea breath test in Helicobacter pylori diagnosis and eradication. Correlation to histology, origin of 'false' results, and influence of food intake.

BACKGROUND: Which protocol is optimal for the 13C-urea breath test (UBT) for Helicobacter pylori detection is controversial. This study aimed to characterize a very simple UBT protocol for the clinical routine (two-point-analysis performed with 75 mg 13C-urea and citric acid) with special consideration of 'false' UBT results. RESULTS; UBT was evaluated in reference to histology (Warthin-Starry). In mismatching results re-gastroscopy was performed. By UBT, 74 of 77 patients with H. pylori-positive histology were detected (sensitivity, 96%). The false-negative UBTs were due to low colonization densities during spontaneous H. pylori elimination or pyloric obstruction. Seven of 49 patients with negative histology had a positive UBT, but re-gastroscopy showed that all of them had a positive histology when multiple antral biopsy specimens were taken (UBT specificity, 100%). UBT correlated only weakly with H. pylori colonization density. No correlation was found between UBT and gastric neutrophil and lymphocyte infiltration. UBT reproducibility was excellent (93 of 94 in a 6-month period). Non-fasting conditions induced a shift to lower UBT results in H. pylori-positive and to higher UBT results in negative patients, resulting in 2 of 10 false-positive and 1 of 10 false-negative UBTs. CONCLUSION: This simple version of the urea breath test combines the highest sensitivity with excellent reproducibility. It is superior to histologic detection of H. pylori in the clinical routine and an optimal tool for monitoring H. pylori eradication. Fasting conditions are required for the test.