Cloning and characterization of a trypsin-encoding cDNA of the human body louse Pediculus humanus

Abstract From a cDNA library of the whole insect, a trypsin gene of Pediculus humanus has been cloned and sequenced. The 908 bp clone has an open reading frame of 759 bp, which encodes a pre-proenzyme with 253 amino acid residues. A sixteen-residue N-terminal signal peptide is followed by a twelve-residue activation peptide with putative cleavage sites at Gly16 and Tyr28. The deduced amino acid sequence has several features typical of trypsin proteases and an overall identity of 35 -43% with the trypsins of several haematophagous Diptera. The 1.0 kb genomic trypsin gene contains three introns of 102, 79 and 80 nucleotides following the codons for Gly16, Gln74 and Ala155, respectively. Only a single gene seems to be present. In Northern blot analysis, unfed first instar larvae have an identical or slightly lower level of trypsin mRNA than fed adult lice, and in adults 2-24 h after the bloodmeal this gene shows a constitutive expression. After in vitro transcription and translation, the activation peptide is cleaved by chymotrypsin, a so far unreported phenomenon in trypsin activation

norUrsodeoxycholic acid improves cholestasis in primary sclerosing cholangitis

Background & Aim Primary sclerosing cholangitis (PSC) represents a devastating bile duct disease, currently lacking effective medical therapy. 24-norursodeoxycholic acid (norUDCA) is a side chain-shortened C23 homologue of UDCA and has shown potent anti-cholestatic, anti-inflammatory and anti-fibrotic properties in a preclinical PSC mouse model. A randomized controlled trial, including 38 centers from 12 European countries, evaluated the safety and efficacy of three doses of oral norUDCA (500 mg/d, 1,000 mg/d or 1,500 mg/d) compared with placebo in patients with PSC. Methods One hundred sixty-one PSC patients without concomitant UDCA therapy and with elevated serum alkaline phosphatase (ALP) levels were randomized for a 12-week treatment followed by a 4-week follow-up. The primary efficacy endpoint was the mean relative change in ALP levels between baseline and end of treatment visit. Results norUDCA reduced ALP levels by −12.3%, −17.3%, and −26.0% in the 500, 1,000, and 1,500 mg/d groups (p = 0.029, p = 0.003, and p <0.0001 when compared to placebo), respectively, while a +1.2% increase was observed in the placebo group. Similar dose-dependent results were found for secondary endpoints, such as ALT, AST, γ-GT, or the rate of patients achieving ALP levels <1.5× ULN. Serious adverse events occurred in seven patients in the 500 mg/d, five patients in the 1,000 mg/d, two patients in the 1500 mg/d group, and three in the placebo group. There was no difference in reported pruritus between treatment and placebo groups. Conclusions norUDCA significantly reduced ALP values dose-dependently in all treatment arms. The safety profile of norUDCA was excellent and comparable to placebo. Consequently, these results justify a phase III trial of norUDCA in PSC patients