Intramolecular Folding in Human ILPR Fragment with Three C-Rich Repeats

Enrichment of four tandem repeats of guanine (G) rich and cytosine (C) rich sequences in functionally important regions of human genome forebodes the biological implications of four-stranded DNA structures, such as G-quadruplex and i-motif, that can form in these sequences. However, there have been few reports on the intramolecular formation of non-B DNA structures in less than four tandem repeats of G or C rich sequences. Here, using mechanical unfolding at the single-molecule level, electrophoretic mobility shift assay (EMSA), circular dichroism (CD), and ultraviolet (UV) spectroscopy, we report an intramolecularly folded non-B DNA structure in three tandem cytosine rich repeats, 5'-TGTC4ACAC4TGTC4ACA (ILPR-I3), in the human insulin linked polymorphic region (ILPR). The thermal denaturation analyses of the sequences with systematic C to T mutations have suggested that the structure is linchpinned by a stack of hemiprotonated cytosine pairs between two terminal C4 tracts. Mechanical unfolding and Br2 footprinting experiments on a mixture of the ILPR-I3 and a 5′-C4TGT fragment have further indicated that the structure serves as a building block for intermolecular i-motif formation. The existence of such a conformation under acidic or neutral pH complies with the strand-by-strand folding pathway of ILPR i-motif structures

Conservative surgical management of Boerhaave's syndrome: experience of two tertiary referral centers.

International audienceBACKGROUND: Surgery is generally proposed for Boerhaave's syndrome, spontaneous rupture of the esophagus. But diagnosis can be difficult, delaying appropriate management. The purpose of the present study was to evaluate outcome of conservative surgery for primary or T-tube repair performed in two tertiary referral centers. METHODS: From June 1985 to November 2010, among 53 patients presenting with Boerhaave's syndrome treated surgically, 39 underwent a conservative procedure. These patients were retrospectively divided into two groups by type of repair: primary suture (group 1, n = 25) or suture on a T-tube (group 2, n = 14). Patients in group 1 were further stratified into two subgroups depending on whether the primary suture was made with reinforcement (subgroup rS) or not (subgroup S). RESULTS: Length of stays in hospital and intensive care were shorter in patients in group 1 (p = 0.037), but after a shorter delay before therapeutic management (p = 0.003) compared with group 2. For the other variables studied, outcome was more favorable in group 1, but the differences were not significant. Comparing subgroups rS and S showed that the rate of persistent leakage was significantly lower after reinforced suture (p = 0.021). CONCLUSIONS: These findings from the largest reported cohort of Boerhaave's syndrome patients undergoing conservative surgery showed that primary and T-tube repair provide at least equivalent results. Reinforced sutures appear to provide better outcomes by reducing postoperative leakage