Levocetirizine is an effective treatment in patients suffering from chronic idiopathic urticaria: a randomized, double-blind, placebo-controlled, parallel, multicenter study

BACKGROUND: Chronic idiopathic urticaria (CIU) is defined by the almost daily presence of urticaria for at least 6 weeks without an identifiable cause. Symptoms include short-lived wheals, itching, and erythema. CIU impedes significantly a patient's quality of life (QoL). Levocetirizine is an antihistamine from the latest generation approved for CIU. AIM: To investigate the efficacy of levocetirizine, 5 mg, and placebo for the symptoms and signs of CIU, as well as for the QoL and productivity. METHODS: The primary criteria of evaluation were the pruritus severity scores over 1 week of treatment and over 4 weeks. The QoL was assessed via the Dermatology Life Quality Index (DLQI). RESULTS: Baseline pruritus severity scores were comparable in the two treatment groups (2.06+/-0.58). After 1 week, levocetirizine was superior to placebo and demonstrated a considerable efficacy (difference=0.78, P<0.001). This efficacy was maintained over the entire study period (4 weeks, P<0.001). The number and size of wheals were considerably reduced compared with placebo over 1 week and over the total treatment period (P paralleled by an improvement in the QoL (DLQI: 7.3 units in the levocetirizine group and 2.4 units in the placebo group) and a higher productivity at work in the levocetirizine group (3.0 workdays lost per patient per month in the placebo group, 0.3 in the levocetirizine group). No unexpected adverse events occurred. CONCLUSIONS: Levocetirizine, 5 mg once daily, is an effective treatment for CIU, characterized not only by a rapid and sustained response, but also by an important improvement in QoL.

Enumerating constrained elementary flux vectors of metabolic networks

The concept of elementary vector is generalised to the case where the steady-state space of the metabolic network is not a flux cone but is a general polyhedron due to further inhomogeneous constraints on the flows through some of the reactions. On one hand, this allows to selectively enumerate elementary modes which satisfy certain optimality criteria and this can yield a large computational gain compared with full enumeration. On the other hand, in contrast to the single optimum found by executing a linear program, this enables a comprehensive description of the set of alternate optima often encountered in flux balance analysis. The concepts are illustrated on a metabolic network model of human cardiac mitochondria.

Antibiotic-dependent correlation between drug-induced killing and loss of luminescence in Streptococcus gordonii expressing luciferase

Measuring antibiotic-induced killing relies on time-consuming biological tests. The firefly luciferase gene (luc) was successfully used as a reporter gene to assess antibiotic efficacy rapidly in slow-growing Mycobacterium tuberculosis. We tested whether luc expression could also provide a rapid evaluation of bactericidal drugs in Streptococcus gordonii. The suicide vectors pFW5luc and a modified version of pJDC9 carrying a promoterless luc gene were used to construct transcriptional-fusion mutants. One mutant susceptible to penicillin-induced killing (LMI2) and three penicillin-tolerant derivatives (LMI103, LMI104, and LMI105) producing luciferase under independent streptococcal promoters were tested. The correlation between antibiotic-induced killing and luminescence was determined with mechanistically unrelated drugs. Chloramphenicol (20 times the MIC) inhibited bacterial growth. In parallel, luciferase stopped increasing and remained stable, as determined by luminescence and Western blots. Ciprofloxacin (200 times the MIC) rapidly killed 1.5 log10 CFU/ml in 2-4 hr. Luminescence decreased simultaneously by 10-fold. In contrast, penicillin (200 times the MIC) gave discordant results. Although killing was slow (< or = 0.5 log10 CFU/ml in 2 hr), luminescence dropped abruptly by 50-100-times in the same time. Inactivating penicillin with penicillinase restored luminescence, irrespective of viable counts. This was not due to altered luciferase expression or stability, suggesting some kind of post-translational modification. Luciferase shares homology with aminoacyl-tRNA synthetase and acyl-CoA ligase, which might be regulated by macromolecule synthesis and hence affected in penicillin-inhibited cells. Because of resemblance, luciferase might be down-regulated simultaneously. Luminescence cannot be universally used to predict antibiotic-induced killing. Thus, introducing reporter enzymes sharing mechanistic similarities with normal metabolic reactions might reveal other effects than those expected.