Survival analysis and microarray profiling identify Cd40 as a candidate for the Salmonella susceptibility locus, Ity5.

The outcome of infection with Salmonella Typhimurium in mouse models of human typhoid fever is dependent upon a coordinated complex immune response. A panel of recombinant congenic strains (RCS) derived from reciprocal backcross of A/J and C57BL/6J mice was screened for their susceptibility to Salmonella infection and two susceptibility loci, Ity4 (Immunity to Typhimurium locus 4) and Ity5, were identified. We validated Ity5 in a genetic environment free of the impact of Ity4 using a cross between A/J and 129S6. Using a time-series analysis of genome-wide transcription during infection, comparing A/J with AcB60 mice having a C57BL/6J-derived Ity5 interval, we have identified the differential expression of the positional candidate gene Cd40, Cd40-associated signaling pathways, and the differential expression of numerous genes expressed in neutrophils. CD40 is known to coordinate T cell-dependent B-cell responses and myeloid cell activation. In fact, CD40 signaling is altered in A/J mice as seen by impaired IgM upregulation during infection, decreased Ig class switching, neutropenia, reduced granulocyte recruitment in response to infection and inflammation, and decreased ERK1/2 activity. These results suggest that altered CD40 signaling and granulocyte recruitment in response to infection are responsible for the Ity5-associated Salmonella susceptibility of A/J mice.

Cutting edge: functional characterization of the effect of the C3H/HeJ defect in mice that lack an Lpsn gene: in vivo evidence for a dominant negative mutation.

A point mutation in the Tlr4 gene, which encodes Toll-like receptor 4, has recently been proposed to underlie LPS hyporesponsiveness in C3H/HeJ mice (Lpsd). The data presented herein demonstrate that F1 progeny from crosses between mice that carry a approximately 9-cM deletion of chromosome 4 (including deletion of LpsTlr4) and C3H/HeJ mice (i.e., Lps0 x Lpsd F1 mice) exhibit a pattern of LPS sensitivity, measured by TNF activity, that is indistinguishable from that exhibited by Lpsn x Lpsd F1 progeny and whose average response is "intermediate" to parental responses. Thus, these data provide clear functional support for the hypothesis that the C3H/HeJ defect exerts a dominant negative effect on LPS sensitivity; however, expression of a normal Toll-like receptor 4 molecule is apparently not required.

A randomized, placebo-controlled, double-blind trial of mesalamine in the maintenance of remission of Crohn's disease. The Canadian Mesalamine for Remission of Crohn's Disease Study Group.

BACKGROUND & AIMS: The efficacy of mesalamine for the maintenance of remission in patients with Crohn's disease is controversial. The aim of this study was to conduct a double-blind, placebo-controlled study of mesalamine (750 mg four times a day for 48 weeks) in maintaining remission in 293 patients with Crohn's disease. Patients were stratified according to the method of induction of remission (medical or surgical). METHODS: Patients were assessed at weeks 4, 12, 24, 36, and 48. Relapse was defined as a Crohn's Disease Activity Index of >150 (+60 points over baseline). RESULTS: Of the 293 patients, 246 (84%) returned for at least 4 weeks of follow-up and were included in the final analysis. Thirty of the 118 (25%) who received mesalamine had a relapse compared with 47 of 128 (36%) receiving placebo (P = 0.056). Among those with relapse, the time to relapse was 119 days for the mesalamine-treated patients compared with 109 days for placebo-treated patients (P = NS). However, 25% of mesalamine-treated patients had relapsed by 249 days of follow-up compared with 154 days for placebo-treated patients. Subgroup analysis showed that patients with ileocecal-colonic disease or patients who were women had fewer relapses on mesalamine therapy than placebo-treated patients (21% vs. 41%, P = 0.018; and 19% vs. 41%, P = 0.003, respectively). CONCLUSIONS: Mesalamine treatment reduced relapse compared with placebo treatment, although conventional statistical significance was not achieved.

Electron-capture gas chromatographic determination of loprazolam in plasma and a pharmacokinetic application.

A sensitive and specific gas chromatographic method, using an electron capture detector, for the measurement of plasma concentrations of loprazolam (HR-158) is described. Retention times of the hydrolysis product of loprazolam (2-amino-2'-chloro-5-nitrobenzophenone) and of the internal standard (2-amino-2'-fluorobenzophenone) were, respectively, 9 and 7 minutes. The sensitivity of the assay was 1.0 ng ml-1 of plasma, and for drug concentrations ranging from 1.0 to 15 ng ml-1 the mean recovery from plasma was 94.4 per cent and the mean coefficient of variation 9.8 per cent. This method was used to determine some pharmacokinetic parameters of loprazolam after administration of 2 X 1 mg capsule doses to nine healthy, fasted volunteers. The mean t 1/2 was 6.4 h, mean AUC infinity 65.42 ng.h ml-1, and the mean clearance 0.51 l min-1.