MEG3 long noncoding RNA regulates the TGF-β pathway genes through formation of RNA-DNA triplex structures

Long noncoding RNAs (lncRNAs) regulate gene expression by association with chromatin, but how they target chromatin remains poorly understood. We have used chromatin RNA immunoprecipitation-coupled high-throughput sequencing to identify 276 lncRNAs enriched in repressive chromatin from breast cancer cells. Using one of the chromatin-interacting lncRNAs, MEG3, we explore the mechanisms by which lncRNAs target chromatin. Here we show that MEG3 and EZH2 share common target genes, including the TGF-β pathway genes. Genome-wide mapping of MEG3 binding sites reveals that MEG3 modulates the activity of TGF-β genes by binding to distal regulatory elements. MEG3 binding sites have GA-rich sequences, which guide MEG3 to the chromatin through RNA-DNA triplex formation. We have found that RNA-DNA triplex structures are widespread and are present over the MEG3 binding sites associated with the TGF-β pathway genes. Our findings suggest that RNA-DNA triplex formation could be a general characteristic of target gene recognition by the chromatin-interacting lncRNAs

A multicentric study of the efficacy and safety of netilmicin in abdominal infections comparing a once-daily versus thrice-daily dosage schedule

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A multicentric study of netilmicin once daily versus thrice daily in patients with appendicitis and other intra-abdominal infections

This multicentric, randomized, double-blind trial compared the efficacy and safety of netilmicin, 4.5 mg/kg od and 1.5 mg/kg tid, in patients with intra-abdominal infections. Of 114 patients enrolled, 57 patients (mean age 40.3 years) in the od group and 55 (mean age 36.8 years) in the tid group were evaluated for efficacy; 58 and 56 patients in corresponding groups were evaluated for safety. Among those evaluated for efficacy were 12 od-treated and 11 tid-treated patients with documented septicaemia, and 32 and 30 patients of respective groups with polymicrobial infections. Initially, 86 and 81 netilmicin-susceptible causative microorganisms were isolated in corresponding groups. Of these pathogens, 55% in the od group and 62% in the tid group were Escherichia coli. Daily dosage of netilmicin ranged from 3.70 to 4.71 mg/kg (mean 4.50) for the od group and from 3.06 to 4.76 mg/kg (mean 4.46) for the tid group. Duration of netilmicin therapy ranged from six to 13 days (mean 8.7 days) for od-treated patients and from seven to 16 days (mean 8.8 days) for tid-treated patients. Concomitant metronidazole was administered to 41 patients of the od group and 34 of the tid group; one patient in the tid group received clindamycin. Clinical and bacteriological responses were assessed, and peak and trough serum netilmicin levels were measured periodically during therapy. Laboratory tests, including determinations of serum creatinine and blood urea nitrogen values, were performed throughout the trial. A clinical cure was achieved in 57/57 od-treated patients and 54/55 tid-treated patients; treatment failed in one tid-treated patient (1/55). In od and tid groups, 86/86 and 80/81 netilmicin-susceptible pathogens initially isolated were considered to be eliminated, respectively; one isolate (Esch. coli) persisted in the tid group. Mean peak serum netilmicin concentration in the od group was approximately two-fold greater than that in the tid group; mean trough serum netilmicin concentrations were similar for the two groups. Adverse reactions were limited to mild pain at the site of netilmicin administration in several patients in each treatment group. Netilmicin od and tid (alone or in combination with metronidazole) were similarly efficacious in the treatment of patients with appendicitis and other intra-abdominal infections caused by netilmicin-susceptible pathogens. Both dosage regimens of netilmicin were safe and well tolerated.link_to_subscribed_fulltex

Response profiles to amino acid odorants of olfactory glomeruli in larval Xenopus laevis

Glomeruli in the vertebrate olfactory bulb (OB) appear as anatomically discrete modules receiving direct input from the olfactory epithelium (OE) via axons of olfactory receptor neurons (ORNs). The response profiles with respect to amino acids (AAs) of a large number of ORNs in larval Xenopus laevis have been recently determined and analysed. Here we report on Ca2+ imaging experiments in a nose–brain preparation of the same species at the same developmental stages. We recorded responses to AAs of glomeruli in the OB and determined the response profiles to AAs of individual glomeruli. We describe the general features of AA-responsive glomeruli and compare their response profiles to AAs with those of ORNs obtained in our previous study. A large number of past studies have focused either on odorant responses in the OE or on odorant-induced responses in the OB. However, a thorough comparison of odorant-induced responses of both stages, ORNs and glomeruli of the same species is as yet lacking. The glomerular response profiles reported herein markedly differ from the previously obtained response profiles of ORNs in that glomeruli clearly have narrower selectivity profiles than ORNs. We discuss possible explanations for the different selectivity profiles of glomeruli and ORNs in the context of the development of the olfactory map