Crystal state conformation of three model monomer units for the β-bend ribbon structure

The molecular and crystal structures of three compounds, representing the repeating units of the β-bend ribbon (an approximate 310-helix, with an intramolecular hydrogen-bonding donor every two residues), have been determined by x-ray diffraction. They are Boc-Aib-Hib-NHBzl, Z-Aib-Hib-NHBzl, and Z-L-Hyp-Aib-NHMe (Aib, α-aminoisobutyric acid; Bzl, benzyl; Boc, t-butyloxycarbonyl; Hyp, hydroxyproline Hib, α-hydroxyisobutyric acid; Z, benzyloxycarbonyl). The two former compounds are folded in a -bend conformation: type III (III′) for Boc-Aib-Hib-NHBzl, while type II (II′) for the Z analogue. Conversely, the structure of Z-L-Hyp-Aib-NHMe, although not far from a type II β-bend, is partially open

Probing structural requirements of fMLP receptor: on the size of the hydrophobic pocket corresponding to residue 2 of the tripeptide.

The conformationally constrained f-L-Met-Ac(n)c-L-Phe-OMe (n = 4,9-12) tripeptides, analogues of the chemoattractant f-L-Met-L-Leu-L-Phe-OH, were synthesized in solution by classical methods and fully characterized. These compounds and the published f-L-Met-Xxx-L-Phe-OMe (Xxx = Aib and Ac(n)c where n = 3, 5-8) analogues were compared to determine the combined effect of backbone preferred conformation and side-chain bulkiness at position 2 on the relation of 3D-structure to biological activity. A conformational study of all the analogues was performed in solution by FT-IR absorption and 1H-NMR techniques. In parallel, each peptide was tested for its ability to induce chemotaxis, superoxide anion production and lysozyme secretion from human neutrophils. The biological and conformational data are discussed in relation to the proposed model of the chemotactic receptor on neutrophils, in particular of the hydrophobic pocket accommodating residue 2 of the tripeptide

Polyacrylonitrile hemofiltration for the adsorption myoglobin in tardy revascularization syndrome: in vitro assessment

The Authors examine the behavior of P.A.N. membranes hemoperfusion combined with district hemodialysis in the prevention of tardy revascularization syndrome. Their experience "in vitro" seems to confirm the use of P.A.N. membrane is advisable whenever an increase of the myoglobin concentration occurs and they also envisage the use of the P.A.N. membrane in the prevention of T.R.S

Structure-Activity Relationship in the Mutagenic Effect of Chiral or Racemic 2-Bromo-2-propanamides on Salmonella typhimurium

none7---noneL. Dolzani; M. Tamaro; C. Lagatolla; C. Monti-Bragadin; G. Cavicchioni; P. Marchetti; F. D'AngeliL., Dolzani; M., Tamaro; C., Lagatolla; C., Monti Bragadin; Cavicchioni, Giorgio; Marchetti, Paolo; F., D'Angel

Amnioreduction for treatment of severe polyhydramnios

Acta Bio Me

Laparoscopic splenectomy for atraumatic splenic rupture

Atraumatic splenic rupture (ASR) is a rare clinical entity. Several underlying benign and malignant conditions have been described as a leading cause. We report on a case of ASR in a 41-year-old man treated with laparoscopic splenectomy. Considering ASR as a lifethreatening condition, a prompt diagnosis can be life saving