Chronic low back pain and postural rehabilitation exercise: a literature review.

Chronic low back represents one of the major causes of disability worldwide. Our narrative review has the purpose of highlighting the evidence supporting the different rehabilitative techniques described for its management. In total, 26 studies were found suitable to be included in the review (14 articles about pilates, six about McKenzie (MK), one article about Feldenkrais, three about Global Postural Rehabilitation (GPR) and two about Proprioceptive Neuromuscular Facilitation). The effect of exercise therapy was examined for each single study through changes in the main clinical outcomes (pain, disability,) quality of life (QoL) and psychological aspects and the targeted aspects of physical function (muscle strength, mobility, muscular activity and flexibility). All the techniques are effective for the study groups with respect to the control groups in reducing pain and disability and improving the QoL and maintaining benefits at follow-up; pilates, Back School, MK and Feldenkrais methods reduce pain and are more efficient than a pharmacological or instrumental approach in reducing disability and improving all psychological aspects also. GPR shows long lasting results for the last outcome. To date, it is difficult to affirm the superiority of one approach over another. Further high quality research is needed to confirm the effect of these techniques, together with the use of more appropriate evaluation measures.

Mild and reversible dehydration of primary amides with PdCl2 in aqueous acetonitrile.

[reaction: see text] A new, mild, and reversible method to convert primary amides to nitriles in good yields using PdCl2 in aqueous acetonitrile is described.

Antibiotics GE23077, novel inhibitors of bacterial RNA polymerase. II. Structure elucidation.

During the screening program for new antibacterial agents produced by actinomycetes, GE23077 was isolated from fermentation broths of an Actinomadura sp. strain as a complex of factors A1, A2, B1, B2. NMR, MS and GC/MS analysis carried out on the isolated components led to the conclusion that GE23077 is a novel cyclic heptapeptide consisting of common and unusual amino acids. The chemical structures of the complex components were elucidated. Components A and B differ in the structure of the acyl group connected to a 2,3-diaminopropanoic acid moiety. A alpha-amino-malonic acid residue in the peptidic sequence is the origin of an isomerization process between A1 and A2 as well as B1 and B2. The chirality of the alpha-amino-malonic acid residue can be inverted easily via keto-enol tautomerism. Factors A2 and B2 should be considered as epimers of A1 and B1 respectively. By degradation studies the absolute configuration of some amino acids were determined. Chiral GC-MS and Micellar Electrokinetic Capillary Chromatography (MEKC) were used to define the absolute stereochemistries of five out of ten chiral centers.

Production and characterization of monochlorinated and dechlorinated A40926 derivatives.

Nonomuraea sp. ATCC 39727 is the producer of the A40926 complex of lipoglycopeptide antibiotics which contain chlorine atoms in amino acids 3 and 6 of the peptide backbone. Using a classical mutagenesis and selection approach we have isolated a Nonomuraea sp. ATCC 39727 mutant strain able to direct production towards new A40926 analogues dechloro-A40926 (DDC) lacking two chlorine atoms and the two monochloro-A40926 (MDC1 and MDC2) that are not produced fermenting the wild type strain. Dechlorinated A40926 derivatives were obtained in considerable amount in a standard fermentation process and were purified and chemically characterized. The dechlorinated A40926 derivatives DDC and MDC2 showed improved antimicrobial activity against coagulase negative staphylococci strains in respect to A40926 complex. Dechlorinated derivatives of the related antibiotic teicoplanin are also reported in the literature and are generally less active than the parental products.

Novel tetrapeptide inhibitors of bacterial protein synthesis produced by a Streptomyces sp.

In the course of a microbial product screening aimed at the discovery of novel antibiotics acting on bacterial protein synthesis, a complex of three structurally related tetrapeptides, namely, GE81112 factors A, B, and B1, was isolated from a Streptomyces sp. The screening was based on a cell-free assay of bacterial protein synthesis driven by a model mRNA containing natural initiation signals. In this study we report the production, isolation, and structure determination of these novel, potent and selective inhibitors of cell-free bacterial protein synthesis, which stably bind the 30S ribosomal subunit and inhibit the formation of fMet-puromycin. They did not inhibit translation by yeast ribosomes in vitro. Spectroscopic analyses revealed that they are tetrapeptides constituted by uncommon amino acids. While GE81112 factors A, B, and B1 were effective in inhibiting bacterial protein synthesis in vitro, they were less active against Gram-positive and Gram-negative bacterial cells. Cells grown in minimal medium were more susceptible to the compounds than those grown in rich medium, and this is most likely due to competition or regulation by medium components during peptide uptake. The novelty of the chemical structure and of the specific mode of action on the initiation phase of bacterial protein synthesis makes GE81112 a unique scaffold for designing new drugs.

Antibiotics GE23077, novel inhibitors of bacterial RNA polymerase. Part 3: Chemical derivatization.

GE23077 is a novel RNA polymerase inhibitor that is isolated from the fermentation broth of an Actinomadura sp. It is a cyclic heptapeptide complex made up of four factors, differing in the structure of acyl group connected to the side chain of an alpha,beta-diaminopropanoic acid moiety and in the configuration of the stereocenter of an alpha-amino-malonic acid residue. Although GE23077 shows strong inhibitory activity on both Rifampicin-sensitive and -resistant polymerases, it exhibits poor antimicrobial activity. The most reasonable explanation for this property has been based on the lack of penetration of the molecule across the bacterial membrane, owing to its strong hydrophilic character. To improve penetration, several parts of the molecule were accordingly modified with the aim of altering the physico-chemical properties of GE23077. The current SAR study has identified moieties important for RNA polymerase activity.