Thomas A. Hinterleitner

Anti-cardiolipin antibodies in patients with inflammatory bowel disease.

Elevated levels of anti-cardiolipin antibodiesare associated with an increased risk for venous andarterial thrombosis. In patients with inflammatory boweldisease thrombosis is a well known complication. We determined the prevalence of elevatedanti-cardiolipin antibodies in 136 patients withinflammatory bowel disease compared with 136 healthycontrols and analyzed thromboembolic complications inpatients with increased anti-cardiolipin antibodylevels. Anti-cardiolipin antibody titers weresignificantly elevated in patients with Crohns disease(5.7 units/ml) and ulcerative colitis (5.3 units/ml)compared to the control group (2.5 units/ml). We foundno correlation between disease activity andanti-cardiolipin antibody levels. Seven patients haddeep venous thrombosis in their history, in three ofthem this was complicated by pulmonary embolism. In onlytwo of the seven patients with deep venous thrombosiswere anti-cardiolipin antibody levels increased. Inconclusion, anti-cardiolipin antibody titers were significantly increased in patients withinflammatory bowel disease. Elevated anti-cardiolipinantibody levels appear to play no role in thepathogenesis of thromboembolic events in patients withinflammatory bowel disease.

Alterations in the colonic microbiota in response to osmotic diarrhea.

Background & Aims Diseases of the human gastrointestinal (GI) tract are often accompanied by diarrhea with profound alterations in the GI microbiota termed dysbiosis. Whether dysbiosis is due to the disease itself or to the accompanying diarrhea remains elusive. With this study we characterized the net effects of osmotic diarrhea on the composition of the GI microbiota in the absence of disease. Methods We induced osmotic diarrhea in four healthy adults by oral administration of polyethylene glycol 4000 (PEG). Stool as well as mucosa specimens were collected before, during and after diarrhea and 16S rDNA-based microbial community profiling was used to assess the microbial community structure. Results Stool and mucosal microbiotas were strikingly different, with Firmicutes dominating the mucosa and Bacteroidetes the stools. Osmotic diarrhea decreased phylotype richness and showed a strong tendency to equalize the otherwise individualized microbiotas on the mucosa. Moreover, diarrhea led to significant relative shifts in the phyla Bacteroidetes and Firmicutes and to a relative increase in the abundance of Proteobacteria on the mucosa, a phenomenon also noted in several inflammatory and diarrheal GI diseases. Conclusions Changes in microbial community structure induced by osmotic diarrhea are profound and show similarities to changes observed in other GI diseases including IBD. These effects so must be considered when specimens from diarrheal diseases (i.e. obtained by stratification of samples according to diarrheal status) or conditions wherein bowel preparations like PEG (i.e. specimens obtained during endoscopy) are used.

Role of Klebsiella oxytoca in Antibiotic-Associated Diarrhea

BACKGROUND Klebsiella oxytoca was recently shown to be the causative agent of antibiotic-associated hemorrhagic colitis. Because it is unclear whether K. oxytoca also causes nonhemorrhagic antibiotic-associated diarrhea, our study investigated a possible association between K. oxytoca and that disorder. METHODS A total of 371 consecutive patients were recruited into 4 study groups: (1) group A+D+ (patients who received antibiotics and experienced diarrhea; n = 107), (2) group A+D- (patients who received antibiotics but did not experience diarrhea; np93), (3) group A-D+ (patients who experienced acute-onset diarrhea but did not receive antibiotics; n = 60), and (4) group A-D- (patients without diarrhea who did not receive antibiotics; n = 111). Stool samples were plated on MacConkey agar and K. oxytoca was identified using a standard test kit. Clostridium difficile was detected by a toxin A/B antigen test. K. oxytoca strains were tested for cytotoxicity with use of cell-culture assays. RESULTS In 15 of 371 stool samples, K. oxytoca strains were isolated during the study period. There was no significant difference in the distribution of K. oxytoca among the 4 study groups. Six of the 15 strains were found to be toxin producing. Three of the toxin-producing strains caused antibiotic-associated hemorrhagic colitis. No case of nonhemorrhagic antibiotic-associated diarrhea due to toxin-producing K. oxytoca was detected. CONCLUSION K. oxytoca is not the causative agent of nonhemorrhagic antibiotic-associated diarrhea. This is in contrast to the distinct clinical entity of antibiotic-associated hemorrhagic colitis. Testing for K. oxytoca is therefore only warranted for patients who experience bloody diarrhea during antibiotic therapy.

Acetorphan prevents cholera-toxin-induced water and electrolyte secretion in the human jejunum

Objectives: Acetorphan is an orally administered inhibitor of enkephalinase in the wall of the digestive tract. It prevents inactivation of endogenous opioid peptides released by submucosal and myenteric neurons. The aim of this study was to examine the effect of acetorphan on jejunal water and electrolyte transport in healthy volunteers under basal conditions and in a state of intestinal secretion induced by a bacterial enterotoxin. Design: Ten volunteers in two groups were studied in an open trial. For the experimental design an intestinal perfusion technique was used. Methods: Cholera toxin was used to induce intestinal secretion in a model employing segmental perfusion of the human proximal jejunum. Acetorphan was given orally prior to intrajejunal administration of cholera toxin; its effect on intestinal transport was measured over a period of four hours after exposure to cholera toxin. Serum levels of methylthioether of thiorphan as the main metabolite were measured throughout three experiments to assure sufficient drug absorption. Results: Acetorphan had no influence on basal water and electrolyte absorption (133 vs. 140ml/30cmh). In a control group with cholera toxin alone, significant water secretion was induced (131 ml/30cm·h). Acetorphan completely prevented this secretion by leaving an absorption rate of 27 ml/30 cmh. Intestinal electrolyte transport was also significantly changed towards absorption by acetorphan. Conclusion: Acetorphan can prevent jejunal water and electrolyte secretion induced by cholera toxin. Enkephalins may thus protect the small intestine from enterotoxininduced secretion.

Renal cell carcinoma metastatic to the stomach: single‐centre experience and literature review

To investigate the incidence, clinical presentation and therapy of gastric metastases, an uncommon finding, in a large group of patients with renal cell carcinoma (RCC).

Effect of neuropeptide Y on jejunal water and ion transport in humans

Neuropeptide Y is a neurotransmitter in enteric and postganglionic sympathetic neurons. In animal models of intestinal water and ion transport, neuropeptide Y decreases stimulated secretion but has no consistent effect on basal transport. In the present study, the effect of neuropeptide Y on jejunal water and electrolyte transport in healthy volunteers was investigated under basal conditions and during intestinal secretion induced by intraluminal administration of prostaglandin E2. The triple-lumen tube technique was used for perfusion of the small intestine with a plasmalike electrolyte solution containing polyethylene glycol as a nonabsorbable volume marker. After an initial control period (saline IV) neuropeptide Y was administered IV at a dose of 400 pmol.kg-1.h-1. Neuropeptide Y significantly increased net absorption of water, sodium, potassium, and chloride under basal conditions. The peptide significantly reduced the secretion of these electrolytes induced by an intraluminal prostaglandin E2 concentration of 5 mumol/L and reduced net water secretion by 36%. The results of the current study suggest that neuropeptide Y can change intestinal water and ion transport from secretion toward absorption.

Cytotoxic Effects of Klebsiella oxytoca Strains Isolated from Patients with Antibiotic-Associated Hemorrhagic Colitis or Other Diseases Caused by Infections and from Healthy Subjects

ABSTRACT Antibiotic-associated hemorrhagic colitis (AAHC) is associated with Klebsiella oxytoca. This study analyzed whether cytotoxic properties are linked to specific subtypes of K. oxytoca. Klebsiella isolates from stools of AAHC patients, healthy carriers, and diarrhea patients as well as from infections of other organs were investigated. Cytotoxic effects on human epithelial cells were limited to the species K. oxytoca and were not detectable for any other Klebsiella species. Isolates from AAHC patients and from stools showed the highest proportion of cytotoxic strains. Urinary or respiratory tract isolates exhibited no cytotoxicity. Macrorestriction profiling of strains revealed no genetic relationships of AAHC isolates or the cytotoxic phenotype but identified that different K. oxytoca strains with different cytotoxic behaviors may be prevalent in the same AAHC patient. Under laboratory conditions, cytotoxicity was maximally effective after exponential bacterial growth and then declined despite the continued viability of K. oxytoca cells in culture. Given its capacity to induce AAHC and that a high proportion of stool isolates tested cytotoxin positive, we argue that K. oxytoca should be considered an opportunistic pathogen if detected in stools. The ability to induce disease after antibiotic treatment most likely represents an overgrowth of the toxin-producing bacterium due to an alteration of the normal colonic microflora.

Effect of cholera toxin on the human jejunum.

In order to develop a model for secretory diarrhoea and to confirm the in vitro effects of cholera toxin in man in vivo the effect of intrajejunally administered cholera toxin was investigated in healthy volunteers. An intestinal perfusion technique with an occluding balloon proximal to the infusion site was used. The jejunum was perfused under steady state conditions with a plasma like electrolyte solution containing polyethylene glycol as a non-absorbable volume marker. After two control periods of one hour each, during which water was absorbed at a rate of 104 (14) (mean (SEM), n = 15) and 94 (15) ml/30 cm/h, respectively, three different doses of cholera toxin (6.25 micrograms, 12.5 micrograms, 25 micrograms) were administered by bolus into the lumen of the jejunum. Cholera toxin reduced absorption of water and electrolytes progressively over four hours and induced secretion in a dose dependent fashion. In the fourth hour net secretion amounted to 22 (23), 36 (24), and 88 (40) ml/30 cm/h (each n = five) with doses of 6.25, 12.5, and 25 micrograms cholera toxin, respectively. The movement of sodium, chloride, and bicarbonate paralleled water movement. Our results suggest that cholera toxin may serve as a secretory model in the human jejunum which might allow testing of new antisecretory agents.

Gastric adenocarcinoma mimicking achalasia in a 15-year-old patient: a case report and review of the literature.

Although adenocarcinoma of the cardia is extremely rare in adolescent patients, the endoscopist should be alert to this disease in patients of any age with dysphagia, even if symptoms, and results of a barium study, upper endoscopy, and esophageal manometry are suggestive of primary achalasia, especially if family history is negative for achalasia. In addition, secondary achalasia should be suspected in patients who do not respond to therapy with botulinum toxin within 2 months. Because none of the mentioned tests can distinguish between primary achalasia and secondary forms due to carcinoma of the cardia, biopsy specimens should be obtained. It appears that, although there is a minimal risk for complications, a diagnostic procedure such as biopsy would be appropriate when the information obtained could be essential. In some cases EUS can be an additional diagnostic tool, because lesions of the submucosa and the surrounding area can be identified by EUS.

Intravenous atrial natriuretic peptide does not affect water and ion transport in the human small intestine

Abstract. Atrial natriuretic peptide (ANP) increases renal sodium and water excretion in several species including man. In rats ANP was also found to influence water and electrolyte transport in the small intestine. In the present study we investigated whether ANP can alter transport in the jejunum and ileum of healthy volunteers using a triple‐lumen perfusion technique. The small intestine was perfused under steady‐state conditions with a plasma‐like electrolyte solution using polyethylene glycol as a nonabsorbable volume marker. After an initial control period with intravenous saline infusion ANP was administered intravenously at a dose of 400 pmol kg‐1 h‐1. This dose led to a significant (P<0.05) increase in the plasma levels of ANP (up to 22‐fold) and cGMP (up to 15‐fold), and of urine volume. Intestinal water and electrolyte transport were, however, not affected by ANP. Our results suggest that circulating ANP does not play a role in the regulation of mucosal water and ion transport in the human small intestine.