Schonlein-Henoch purpura with severe duodenal involvement treated with corticosteroids

A 57 year old woman presented with Schönlein-Henoch purpura and transient glomerulonephritis after streptococcal pharyngitis. Within a week she developed abdominal angina and melena. Endoscopy showed small bowel involvement with severe duodenal inflammataion comprising circular erosions and ulceration beyond the ligament of Treitz. To prevent perforation, high doses of Prednisone (60 mg/day) were successfully given. The small bowel lesions resolved within three weeks (figures 1a and 1b). Presnidone was discontinued after a month and the patient was free of disease six months later

A Cell-based Computational Modeling Approach for Developing Site-Directed Molecular Probes

Modeling the local absorption and retention patterns of membrane-permeant small molecules in a cellular context could facilitate development of site-directed chemical agents for bioimaging or therapeutic applications. Here, we present an integrative approach to this problem, combining in silico computational models, in vitro cell based assays and in vivo biodistribution studies. To target small molecule probes to the epithelial cells of the upper airways, a multiscale computational model of the lung was first used as a screening tool, in silico. Following virtual screening, cell monolayers differentiated on microfabricated pore arrays and multilayer cultures of primary human bronchial epithelial cells differentiated in an air-liquid interface were used to test the local absorption and intracellular retention patterns of selected probes, in vitro. Lastly, experiments involving visualization of bioimaging probe distribution in the lungs after local and systemic administration were used to test the relevance of computational models and cell-based assays, in vivo. The results of in vivo experiments were consistent with the results of in silico simulations, indicating that mitochondrial accumulation of membrane permeant, hydrophilic cations can be used to maximize local exposure and retention, specifically in the upper airways after intratracheal administration

Klebsiella pneumoniae Multiresistance Plasmid pMET1: Similarity with the Yersinia pestis Plasmid pCRY and Integrative Conjugative Elements

Dissemination of antimicrobial resistance genes has become an important public health and biodefense threat. Plasmids are important contributors to the rapid acquisition of antibiotic resistance by pathogenic bacteria.The nucleotide sequence of the Klebsiella pneumoniae multiresistance plasmid pMET1 comprises 41,723 bp and includes Tn1331.2, a transposon that carries the bla(TEM-1) gene and a perfect duplication of a 3-kbp region including the aac(6')-Ib, aadA1, and bla(OXA-9) genes. The replication region of pMET1 has been identified. Replication is independent of DNA polymerase I, and the replication region is highly related to that of the cryptic Yersinia pestis 91001 plasmid pCRY. The potential partition region has the general organization known as the parFG locus. The self-transmissible pMET1 plasmid includes a type IV secretion system consisting of proteins that make up the mating pair formation complex (Mpf) and the DNA transfer (Dtr) system. The Mpf is highly related to those in the plasmid pCRY, the mobilizable high-pathogenicity island from E. coli ECOR31 (HPI(ECOR31)), which has been proposed to be an integrative conjugative element (ICE) progenitor of high-pathogenicity islands in other Enterobacteriaceae including Yersinia species, and ICE(Kp1), an ICE found in a K. pneumoniae strain causing primary liver abscess. The Dtr MobB and MobC proteins are highly related to those of pCRY, but the endonuclease is related to that of plasmid pK245 and has no significant homology with the protein of similar function in pCRY. The region upstream of mobB includes the putative oriT and shares 90% identity with the same region in the HPI(ECOR31).The comparative analyses of pMET1 with pCRY, HPI(ECOR31), and ICE(Kp1 )show a very active rate of genetic exchanges between Enterobacteriaceae including Yersinia species, which represents a high public health and biodefense threat due to transfer of multiple resistance genes to pathogenic Yersinia strains

Modelling of early viral kinetics and pegylated interferon-α2b pharmacokinetics in patients with HBeAg-positive chronic hepatitis B

Background: Pegylated interferon α2b (PEG-IFN-α2b) is effective for the treatment of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B, although its mechanism of action remains unclear. HBeAg loss is achieved in 36% of patients after one year of PEG-IFN-α2b treatment and combination therapy with lamivudine is not superior to PEG-IFN-α2b monotherapy. Methods: Early pharmacokinetics and viral kinetics were analysed in patients treated for 52 weeks with PEG-IFN-α2b with or without lamivudine. Results: After 4 weeks of treatment, there was a median viral decline of 2.94 log 10 copies/ml in those treated with PEG-IFN-α2b and lamivudine and only 0.45 log10 copies/ml in the PEG-IFN-α2b monotherapy group. Peak PEG-IFN-α2b levels were reached approximately one day after administration and subsequently declined exponentially, consistent with a viral load rebound near to baseline levels at the end of the dosing period in most patients receiving PEG-IFN-α2b monotherapy. Modelling of pharmacokinetics and viral kinetics data in this group revealed that viral load was minimal 3.6 days after PEG-IFN-α2b administration, the mean maximal and mean antiviral effectiveness was 70% and 48% with a mean infected cell loss rate of 0.07 per day, while no significant biphasic decline was observed. Conclusions: PEG-IFN-α2b induces a sustained response in a considerable number of patients despite limited direct antiviral activity during the first weeks of antiviral therapy.</p

Modelling of early viral kinetics and pegylated interferon-α2b pharmacokinetics in patients with HBeAg-positive chronic hepatitis B

Background: Pegylated interferon α2b (PEG-IFN-α2b) is effective for the treatment of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B, although its mechanism of action remains unclear. HBeAg loss is achieved in 36% of patients after one year of PEG-IFN-α2b treatment and combination therapy with lamivudine is not superior to PEG-IFN-α2b monotherapy. Methods: Early pharmacokinetics and viral kinetics were analysed in patients treated for 52 weeks with PEG-IFN-α2b with or without lamivudine. Results: After 4 weeks of treatment, there was a median viral decline of 2.94 log 10 copies/ml in those treated with PEG-IFN-α2b and lamivudine and only 0.45 log10 copies/ml in the PEG-IFN-α2b monotherapy group. Peak PEG-IFN-α2b levels were reached approximately one day after administration and subsequently declined exponentially, consistent with a viral load rebound near to baseline levels at the end of the dosing period in most patients receiving PEG-IFN-α2b monotherapy. Modelling of pharmacokinetics and viral kinetics data in this group revealed that viral load was minimal 3.6 days after PEG-IFN-α2b administration, the mean maximal and mean antiviral effectiveness was 70% and 48% with a mean infected cell loss rate of 0.07 per day, while no significant biphasic decline was observed. Conclusions: PEG-IFN-α2b induces a sustained response in a considerable number of patients despite limited direct antiviral activity during the first weeks of antiviral therapy.</p