Second-line therapy with levofloxacin after failure of treatment to eradicate helicobacter pylori infection: time trends in a Spanish Multicenter Study of 1000 patients.

BACKGROUND: Second-line bismuth-containing quadruple therapy is complex and frequently induces adverse effects. A triple rescue regimen containing levofloxacin is a potential alternative; however, resistance to quinolones is rapidly increasing. AIM: To evaluate the efficacy and tolerability of a second-line triple-regimen-containing levofloxacin in patients whose Helicobacter pylori eradication treatment failed and to assess whether the efficacy of the regimen decreases with time. DESIGN: Prospective multicenter study. PATIENTS: In whom treatment with a regimen comprising a proton-pump inhibitor, clarithromycin, and amoxicillin had failed. INTERVENTION: Levofloxacin (500 mg bid), amoxicillin (1 g bid), and omeprazole (20 mg bid) for 10 days. OUTCOME: Eradication was confirmed using the C-urea breath test 4 to 8 weeks after therapy. Compliance/tolerance: Compliance was determined through questioning and recovery of empty medication envelopes. Incidence of adverse effects was evaluated by means of a questionnaire. RESULTS: The study sample comprised 1000 consecutive patients (mean age, 49 ± 15 y, 42% men, 33% peptic ulcer) of whom 97% took all medications correctly. Per-protocol and intention-to-treat eradication rates were 75.1% (95% confidence interval, 72%-78%) and 73.8% (95% confidence interval, 71%-77%). Efficacy (intention-to-treat) was 76% in the year 2006, 68% in 2007, 70% in 2008, 76% in 2009, 74% in 2010, and 81% in 2011. In the multivariate analysis, none of the studied variables (including diagnosis and year of treatment) were associated with success of eradication. Adverse effects were reported in 20% of patients, most commonly nausea (7.9%), metallic taste (3.9%), myalgia (3.1%), and abdominal pain (2.9%). CONCLUSIONS: Ten-day levofloxacin-containing therapy is an encouraging second-line strategy, providing a safe and simple alternative to quadruple therapy in patients whose previous standard triple therapy has failed. The efficacy of this regimen remains stable with time.

Constraints to virus infection in Nicotiana benthamiana plants transformed with a potyvirus amplicon.

BACKGROUND: Plant genomes have been transformed with full-length cDNA copies of viral genomes, giving rise to what has been called 'amplicon' systems, trying to combine the genetic stability of transgenic plants with the elevated replication rate of plant viruses. However, amplicons' performance has been very variable regardless of the virus on which they are based. This has boosted further interest in understanding the underlying mechanisms that cause this behavior differences, and in developing strategies to control amplicon expression. RESULTS: Nicotiana benthamiana plants were transformed with an amplicon consisting of a full-length cDNA of the potyvirus Plum pox virus (PPV) genome modified to include a GFP reporter gene. Amplicon expression exhibited a great variability among different transgenic lines and even among different plants of the same line. Plants of the line 10.6 initially developed without signs of amplicon expression, but at different times some of them started to display sporadic infection foci in leaves approaching maturity. The infection progressed systemically, but at later times the infected plants recovered and returned to an amplicon-inactive state. The failure to detect virus-specific siRNAs in 10.6 plants before amplicon induction and after recovery suggested that a strong amplicon-specific RNA silencing is not established in these plants. However, the coexpression of extra viral silencing suppressors caused some amplicon activation, suggesting that a low level of RNA silencing could be contributing to maintain amplicon repression in the 10.6 plants. The resistance mechanisms that prevent amplicon-derived virus infection were also active against exogenous PPV introduced by mechanical inoculation or grafting, but did not affect other viruses. Amplicon-derived PPV was able to spread into wild type scions grafted in 10.6 rootstocks that did not display signs of amplicon expression, suggesting that resistance has little effect on virus movement. CONCLUSIONS: Our results suggest that amplicon-derived virus infection is limited in this particular transgenic line by a combination of factors, including the presumed low efficiency of the conversion from the transgene transcript to replicable viral RNA, and also by the activation of RNA silencing and other defensive responses of the plant, which are not completely neutralized by viral suppressors.

Effects of phenoxyethanol on the innate immune system of gilthead seabream (Sparus aurata L.) exposed to crowding stress.

Phenoxyethanol is routinely used in seabream aquaculture to minimise fish stress response despite the secondary negative effects which have been observed. In this study, two different doses (60 and 200 microl/l) of phenoxyethanol, sedative and narcotic, were tested for their ability to reduce the stress caused in gilthead seabream (Sparus aurata L.) by crowding. Blood glucose and serum cortisol concentrations were measured as stress indicators. In order to study the effects of the treatment on the innate immune system of crowded specimens, two parameters of the innate immune response, serum complement activity and phagocytosis, were assessed. The results show that anaesthesia itself produced a stress response in the fish and affected the immune system, although the effects were greater with the narcotic dose. When the effects of anaesthesia on crowded fish were analysed, the results pointed to a slight reduction in stress as a result of the sedative dose of phenoxyethanol (lower increase in cortisol and lower reduction in phagocytosis). However, additive negative effects were seen in crowded fish when the narcotic dose of phenoxyethanol was used. Since the use of phenoxyethanol is a common practice in aquaculture, the significance of the results should be considered.

Oral administration of yeast, Saccharomyces cerevisiae, enhances the cellular innate immune response of gilthead seabream (Sparus aurata L.).

The effects of including lyophilised whole yeast, Saccharomyces cerevisiae, in the diet on the seabream innate immune response were investigated. Gilthead seabream (Sparus aurata L.) specimens were fed four different diets for 4 weeks: a commercial diet as control and the same diet supplemented with 1, 5 or 10 g/kg yeast. After 1, 2 and 4 weeks, serum complement titres, as a humoral parameter, and phagocytic, respiratory burst, myeloperoxidase and natural cytotoxic activities of head-kidney leucocytes, as cellular parameters, were evaluated. The results showed that yeast supplements enhanced all the latter responses, but not the humoral response. This enhancement was dose-dependent except for the cytotoxic activity that was only stimulated by the lower dose of yeast assayed. As yeast cell walls are able to enhance the seabream cellular innate immune response, these results support the possible use of whole yeast as natural inmunostimulants in common fish diets.

Lack of effect of combining different stressors on innate immune responses of seabream (Sparus aurata L.).

A complex stressful event, which commonly occurs in modern aquacultural practices, was broken down into factors that were analysed both individually and jointly to assess their effect on two stress indicators (blood glucose and serum cortisol levels) and two activities of the innate immune response (serum complement and head-kidney leukocyte respiratory burst). For this, gilthead seabream (Sparus aurata L.) specimens were exposed to the following stressors: physical disturbance, crowding, anaesthesia with 2-phenoxyethanol and air exposure. At 0, 1, 2, 3 and 4 days post-stress, blood and serum samples were collected to measure glucose concentration and cortisol and complement levels, respectively. Head-kidney leukocytes were isolated and assayed to evaluate respiratory burst activity. The results show that physical disturbance, crowding and anaesthesia produced an occasional increase in glucose and cortisol concentrations. Crowding and anaesthesia induced a depression in complement activity, while hypoxia by air exposure caused a reduction in the respiratory burst. When all factors were jointly applied both humoral and cellular defences were compromised and cortisol values remained high throughout the experimental period. Any long-term effects of this abnormal serum cortisol levels on the immune system remain unknown.