The safety and efficacy of ranitidine bismuth citrate in combination with antibiotics for the eradication of Helicobacter pylori.

BACKGROUND: Ranitidine bismuth citrate is a novel salt of ranitidine and a bismuth citrate complex. It has intrinsic antisecretory and anti-Helicobacter pylori activity, but monotherapy rarely eradicates H. pylori infection in man. AIM: A pilot study to investigate rates of H. pylori eradication achieved by co-prescription of ranitidine bismuth citrate with antibiotics, and to identify several regimens which would merit further investigation. METHOD: One hundred dyspeptic patients infected with H. pylori were randomly allocated to treatment with ranitidine bismuth citrate 800 mg b.d. plus either amoxycillin, metronidazole, clarithromycin, cefuroxime axetil, tetracycline, tetracycline plus metronidazole or clarithromycin plus tetracycline for 14 days. Eradication of infection was assessed using the 13C-urea breath test 4 weeks after the end of treatment. RESULTS: In a per protocol analysis eradication of H. pylori ranged between 22 and 100%; the intention-to-treat eradication rates ranged between 15 and 92%. No adverse events were specifically attributed to ranitidine bismuth citrate. CONCLUSION: Co-prescription therapy, using ranitidine bismuth citrate and one or more antibiotics, is suitable for further investigation in large-scale clinical trials in patients infected with H. pylori.

[Thrombocytes express functional cytokine receptors in patients with Crohn disease and ulcerative colitis]. / Thrombozyten exprimieren funktionelle Zytokinrezeptoren bei Patienten mit M. Crohn und Colitis ulcerosa.

Inflammatory bowel disease (IBD) is characterized by T-cell activation and mucosal influx of inflammatory cells partly mediated by increased local release of cytokines and chemokines. Increased levels of activated platelets are reported in IBD. Activated platelets induce endothelial cells in vitro to secrete several cytokines and growth factors and to express adhesion molecules. This study investigates the expression of interleukin-1 (IL-1), IL-8 and granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors on circulating platelets from patients with IBD and healthy controls and assesses the in vitro effect of various concentrations of IL-1 beta, IL-8 and GM-CSF on platelet activation in healthy controls. Flow cytometry was performed to quantify the percentage of platelets binding phycoerythrin (PE) labeled recombinant human IL-1 beta, IL-8 and GM-CSF. Platelet activation was assessed using fluorochrome labeled anti-GMP-140, an activation-dependent antigen. Results are expressed as percentage cytokine receptor expressing platelets (median and interquartile range IQR). Platelets from patients with IBD expressed significantly more cytokine receptors compared to healthy controls: IL-1R [8.7% (5.5-18.2) vs 3.1% (2.4-4.8), p < 0.05], IL-8R [22.5% (18.1-27.9) vs 8% (4.5-9.2), p < 0.001)], GM-CSFR [25.9% (16.1-39.2) vs 3.9% (2.7-3.9), p < 0.001]. The percentage of activated platelets was significantly increased after in vitro stimulation with IL-1 beta, IL-8 and GM-CSF. We conclude that cytokines and chemokines modulate platelet activation through specific, functional receptors which are upregulated in IBD.

Platelets in ulcerative colitis and Crohn's disease express functional interleukin-1 and interleukin-8 receptors.

Tissue and plasma concentrations of several cytokines are increased in patients with inflammatory bowel disease (IBD). Platelets play an important role in inflammation and circulate in an activated state in patients with IBD. This study assesses the expression of IL-8 and IL-1 receptors on the surface of platelets from patients with IBD using phycoerythrin (PE)-labelled recombinant human rhIL-1 beta and rhIL-8 and flow cytometry. The percentage IL-1R expressing platelets (median and interquartile range IQR) in the IBD group was 8.7% (5.5-18.2) compared to 4.2% (2.3-6.1) in controls (P = 0.02). The percentage IL-8R expressing platelets in the IBD group was 22.5% (16.5-27.9) and 9.2% (4.3-9.6) in controls (P < 0.001). Furthermore, platelet IL-1R expression in patients with IBD was inversely related to the total daily dose of steroids (r = 0.71, P < 0.01 linear regression analysis). Finally, platelet rich plasma from healthy controls was stimulated with rhIL-1 beta and rhIL-8 and assessed for activation dependent expression of platelet aGPIIb/IIIa and CD62 (p-selectin, GMP-140). IL-1 beta and IL-8 in vitro significantly and specifically activated the platelets. The surface membrane of platelets is able to express functional IL-1R and IL-8R, the expression of which is significantly increased in IBD. Interleukin-1 beta and IL-8 modulate platelet activation in vitro indicating a target role for platelet function in inflammation.

Eradication of Helicobacter pylori with clarithromycin and omeprazole.

Clarithromycin, a new and well tolerated, acid stable macrolide antibiotic, has a similar antimicrobial spectrum to erythromycin but a better in vitro MIC90 (0.03 microgram/l-1) against Helicobacter pylori (H pylori). This study aimed at determining the eradication rate using clarithromycin 500 mg thrice daily and omeprazole 40 mg daily for two weeks. Patients were given an endoscopy and H pylori status assessed by antral culture (microaerobic conditions, for up to 10 days), antral and corpus histology tests (haematoxylin and eosin/Gimenez stains), and 13C-urea breath test (13C-UBT, European standard protocol, positive result = excess delta 13CO2 excretion > 5 per mil). Compliance was assessed by returned tablet counts. H pylori clearance at the end of treatment and eradication four weeks after finishing treatment were assessed by the 13C-UBT. Seventy three patients (54 men, median age 45 years) with duodenal ulcers (n = 42) or duodenitis/non-ulcer dyspepsia (n = 31) all with a positive 13C-UBT (mean (SEM) excess delta-13CO2 excretion = 26.6 (4.9) per mil) and either positive antral histology (n = 72) or positive antral culture (n = 35) were studied. Before treatment 2/27 (7%) isolates of H pylori were resistant to clarithromycin and five isolates were resistant to metronidazole. In 70/73 (96%) the 13C-UBT was negative immediately after finishing treatment. Four weeks later the 13C-UBT was negative in 57/73 (mean (SEM) excess delta 13CO2 excretion = 1.2 (0.3) per mil, eradication rate = 78%). Forty eight (66%) patients experienced a metallic taste while taking the tablets. Although four (5%) patients, however, could not complete the course of treatment, in only one of these four was H pylori not eradicated. These results show that duel therapy with clarithromycin and omeprazole is well tolerated. With an eradication rate of 78% it is an effective treatment for metronidazole resistant H pylori and may be an alternative to standard triple therapy.