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Two families of hexameric cyclic peptoids decorated with linear N-alkyl and alternated N-alkyl/N-benzyl side chains (2 a–d and 3 a–c, respectively) were designed and synthesized in order to correlate their logP values (from 2.55 to 6.83) to their ionophoric activities. The present contribution confirms the general ability of hexameric cyclic peptoids to behave as efficient cation carriers, corroborates their preference for Na+ ion, among the tested alkali metals, and suggests a Na+/H+ antiport transport mechanism (rate limited by the transport of the proton) for these new ionophores. Our observations indicate that in order to attain an efficient ionophoric activity, a narrow range of liphophilicity is required (4

A novel asymmetric phase-transfer-catalyzed γ-alkylation of phthalide 3-carboxylic esters has been developed, giving access to 3,3-disubstituted phthalide derivatives, which present a chiral quaternary γ-carbon in good to excellent yields and good enantioselectivities (74–88% ee). The enantiomeric purity could be substantially enhanced to 94–95% ee by recrystallization. Both electron-withdrawing and electron-releasing substituents are well tolerated on the phthalide core as well as on the aromatic moiety of the alkylating agent. This methodology, enabling the introduction of an unfunctionalized group at the phthalide γ-position, fully complements previously reported organocatalytic strategies involving functionalized electrophiles, thus expanding the scope of accessible 3,3-disubstituted products. The high synthetic value of this asymmetric reaction has been proven by the formal synthesis of the naturally occurring alkaloid (+)-(9S,13R)-13-hydroxyisocyclocelabenzine.

Five new cyclic peptoids containing (2S,4R)-4-hydroxyproline (Hyp) residues have been designed and synthesized using a mixed "submonomer/monomer" approach. Alkali metal cation affinities and ion transport activities were assessed by experimental (NMR and HPTS assay in liposomes) and computational methods. Easy functionalization of hydroxyproline residues afforded a bouquet of cyclic oligomers showing correlation between ion transport abilities and cytotoxic activities on selected human cancer cell lines.

An efficient protocol for the solid-phase synthesis of six members of a new class of extended macrocyclic peptoids (based on ortho-, meta- and para-N-(methoxyethyl)aminomethyl phenylacetyl units) is described. Theoretical (DFT) and experimental (NMR) studies on the free and Na+-complexed cyclic trimers (3–5) and tetramers (6–8) demonstrate that annulation of the rigidified peptoids can generate new hosts with the ability to sequestrate one or two sodium cations with the affinities and stoichiometries defined by the macrocycle morphology. Ion transport studies have been also performed in order to better appreciate the factors promoting transmembrane cation translocation.

The preparation of a new class of backbone-modified PNA mimetic incorporating thymine is described. Target dipeptoid monomer 21 was synthesised from an N-[2-(thymin-1-yl)ethyl]glycinate ester and a properly protected iminodiacetic acid. The distinctive structural motif in the backbone is acarboxy group, inserted to impart water solubility to the oligomer. Two achiral oligopeptoid sequences (8-mer and 12-mer), characterised by the shift of the amide carbonyl group away from the nucleobase, were efficiently assembled according to solid-phase synthesis protocols. Thermal denaturation studies showed that the two homopyrimidine oligopeptoids do not effectively hybridise with complementary sequences of DNA and RNA or fully synthetic (2,4-diamino)triazin-6-yl-tagged peptoid 22. A possible reason could reside in the concurrent unfavourable influence of the anionic N-(carboxymethyl) moieties and the flexible nucleobase/backbone ethylene linker.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

A new class of artificial ionophores has been rationally designed and synthesized linking to a tetrafunctionalized l -treitol spacer two rigid hydrophobic 3β-hydroxy-5α-23,24-bisnorcholanic units and two flexible hydrophilic oligo(ethylene glycol) chains. Compounds 1a and 1b were incorporated into phospholipid vesicles and shown to facilitate Na+-transport.

Background Increased risk of fractures and osteoporosis have been associated with the use of antiretroviral drugs. There is a paucity of prospective evaluations of bone markers after the initiation of drugs currently recommended to treat HIV infection and results on the evolution of these markers are conflicting. Lastly, the effect of tenofovir on 1,25-(OH)2 vitamin D is uncertain. Methods We performed a prospective study on the evolution of bone markers, parathormone and 1,25-(OH)2 vitamin D before and after standard antiretroviral regimens. This was a sub-study of a trial conducted in antiretroviral-naïve patients randomized to tenofovir + emtricitabine in combination with either atazanavir/ritonavir (ATV/r) or efavirenz (EFV). Follow-up lasted 48 weeks. The following bone markers were analyzed: C-terminal cross-laps (CTx), osteocalcin (OC), osteoprotegerin (OPG), and receptor activator of nuclear factor κB ligand (RANKL). Mixed-factorial analysis of variance with random-coefficient general linear model was used to compare their trends over time and linear multivariable regression was performed with a backward selection method to assess predictors of their variations from baseline to week 48. Trends of parathormone and 1,25-(OH)2 vitamin D were also evaluated. Results Seventy-five patients were studied: 33 received EFV and 42 ATV/r. Significant increases were found for all markers except for RANKL. There was a significant direct association between CTx and OC increases. Multivariable analysis showed that higher glomerular filtration rate (estimated through cystatin C clearance) predicted greater OPG increase, while older age, higher HIV RNA at baseline and use of ATV/r predicted greater CTx increase. A significant increase of parathormone accompanied the evolution of the study markers. 1,25-(OH)2 vitamin D remained stable, though a seasonality variation was demonstrated. Conclusions These data demonstrate CTx increase (bone resorption marker) corresponding to OC increase (bone formation marker) early upon HAART initiation. Moreover, predictors of bone marker increases have been suggested, possibly indicating that a stricter monitoring of bone health and pro-active interventions are needed in older patients, those with higher HIV RNA, prescribed ATV/r rather than EFV, and with decreased renal function at baseline. Further studies are needed to clarify the mechanisms responsible for up-regulation of bone turnover markers, as well as to understand if and what markers are best correlated or predictive of pathological fractures.

Background: Glomerular filtration rate (GFR) estimated by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation based on creatinine or cystatine C may be more accurate methods especially in patients without chronic kidney disease. There is lack of data on GFR estimated by these methods in patients on highly active antiretroviral therapy. Methods: Antiretroviral-naive HIV-infected patients were randomized to tenofovir/emtricitabine in association with atazanavir/ritonavir (ATV/r) or efavirenz (EFV) Patients had to have an actual creatinine clearance >50 mL/minute (24-hour urine collection) and were followed for 48 weeks. RESULTS: Ninety-one patients (48 ATV/r, 43 EFV) were recruited. Using the CKD-EPI creatinine formula, there was a significant decrease in GFR up to week 48 in patients receiving ATV/r (4.9 mL/minute/m, P = 0.02) compared with a not statistically significant increment in patients prescribed EFV. Using the cystatin C-based equation, we found greater decrease in GFR in both arms, although, in the EFV arm, the decrease was not statistically significant (5.8 mL/minute/m, P = 0.92). At multivariable analysis, ATV/r was a significant predictor of greater decrease in estimated glomerular filtration rate (eGFR) (P = 0.0046) only with CKD-EPI creatinine. Conclusions: ATV/r plus tenofovir caused greater GFR decreases compared with EFV. The evaluation of eGFR by cystatin C confirmed this result, but this method seemed to be more stringent, probably precluding the possibility to detect a significant difference in the pattern of eGFR evolution between the two arms over time. More studies are needed to understand the clinical relevance of these alterations and whether cystatin C is a more appropriate method for monitoring GFR in clinical practice.

Cardiovascular risk in HIV-infected patients is related, at least in part, to serum lipid alterations before and after HAART. Lipoprotein-particle subclasses may also have an effect, but comparative data after standard HAART regimens are limited.This was a substudy of a trial in 91 antiretroviral-naïve patients randomized to tenofovir + emtricitabine + atazanavir/ritonavir (ATV/r) or efavirenz (EFV). Over-time trends from baseline to week 48 in total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), HDL particles (HDLp), and TC:HDL-C and TG:HDL-C ratios were analyzed by analysis of covariance (ANCOVA). Furthermore, confidence intervals for differences between the 2 groups at week 48 were calculated. Indications for lipid-lowering interventions and low HDL-C were also studied.ANCOVA showed that, with respect to patients receiving ATV/r, those prescribed efavirenz (EFV) had greater increases reported as mean differences in lipid values at week 48: 14 mg/dL (95% CI, 0.2 to 27) for TC, 14 mg/dL (95% CI, 4 to 25) for LDL-C, 5 mg/dL (95% CI, 2 to 9) for HDL-C, and 2.2 mg/dL (95% CI, 0.4 to 4) for large HDLp. Proportions of subjects with indications for lipid-lowering interventions and with HDL-C40 mg/dL did not differ significantly.Patients prescribed EFV had greater increases in TC, LDL-C, and HDL-C. Although no significant differences were detected between the 2 groups for the TC:HDL ratio and for indications to start lipid-lowering interventions, large HDLp increased more in the EFV group compared to the ATV/r group, suggesting a protective effect associated with EFV use.

The synthesis and screening of neutral and cationic, linear and cyclic peptoids (N-alkylglycine peptidomimetics) is described. Structure-activity relationship studies show that the in vitro activities of the tested peptoids depend on both cyclization and decoration with cationic groups. The most powerful N-lysine cyclopeptoid derivatives showed good antifungal activity against Candida albicans (ATCC90029 and L21) and Candida famata (SA550, Amph B-resistant) and low hemolytic activity. The effects of the cyclic peptoids on membrane permeabilization were evaluated by the propidium iodide exclusion assay.

Anion transport across phospholipid membrane is a typical supramolecular function involving dynamic recognition of the substrate during the whole translocation process. Supramolecular chemists, taking inspiration by the natural anion transporters, have designed artificial systems able to mimic, at the functional level, several features of the natural ion channels. The scope of this research is twofold: on one hand to get insight on the molecular basis of recognition and transport, and on the other hand to get control of the biomedical relevant processes. The present review focuses on the synthetic systems promoting anion transport, covering both artificial channels and carriers that operate in phospholipid membrane. The design principles of such systems will be discussed together with the potential biomedical applications.

1,3-Alternate cationic calix[4] arene 1 proved highly selective for proton/ halogens symport transport and showed antiproliferative activity against murine monocyte/macrophage J774.A1 cancer cells.

1,3-Alternate calix[4]arenes, decorated with four nonpolar 'all-trans' tetracyclic nuclei and cation-stabilizing beta-methoxyethoxy appendages, were synthesized from commercially available starting materials and through straightforward functional groups transformations/couplings. Their Na+-transport activities, when compared with those exerted by the known conformationally-rigidified 1,3-alternate calix[4]-arene AB/cis cholic acid conjugates, suggest that the cation conductance is related to the morphology of the pendant steroids.

The synthesis of five steroid-oligo(ethyleneglycol) conjugates ( 1 – 5 ) has been accomplished starting from commercially available epi -androsterone ( 8 ) and known 3β-[( tert -butyldiphenylsilyl)oxy]-5α-23,24-bisnorchol-16-en-6α,7β,22-triol ( 27 ). The synthetic strategy was based on a convergent approach including stereoselective C-17 side chains construction and standard coupling reactions. The activities of the head-to-tail amphiphiles, once incorporated in 95:5 egg PC/PG vesicular membranes, have been assessed by direct determination of transported species by NMR techniques ( 23 Na + ) and fluorescence spectroscopy (H + ). The sodium and proton transmembrane transport was compared to those evaluated for the polyene macrolide antibiotic amphotericin B and those shown by the known related C 2 -symmetric sterol-polyether conjugates 6 and 7 .

The synthesis of the C-2-symmetric bis-(20S)-5alpha-23,24-bisnorchol-16-en-3beta,6alpha,7beta-triol-22-terephthaloate (1), active as Na+-transporting transmembrane channel, has been achieved in 16 steps (10% overall yield) starting from the commercially available androst-5-en-3beta-ol-17-one (3). The straightforward stereospecific functionalization of the side-chain, via the 'ene' reaction, and the successful regioselective terephthaloylation of the C-22 hydroxy group, illustrate the efficiency of the synthetic strategy.

SummaryMast cells of connective tissue type are scattered in the interstitial compartment of the lizard Podarcis s. sicula. Their number varies during the year, showing peaks in spring and in winter, respectively.Thermal manipulation affects mast cell number (MCN): high temperature decreased MCN in both January and May, while low temperature increased MCN only in January. Ethane dimethane sulphonate, a toxin which specifically destroys Leydig cells, induced an increase in MCN on days 3 and 7 of treatment. Oestradiol treatment provoked a strong increase in MCN that was blocked by tamoxifen. Blocking androgen receptors with cyproterone acetate resulted in an increase in MCN, while testosterone injection provoked a strong decrease. These results suggest a relationship between the presence of mature Leydig cells and mast cell proliferation and/or differentiation.

The Na+ transporting properties of the first member of a new class of artificial ionophores, based on a C-2-symmetric polyhydroxylated steroid dimer, are described.

The synthesis of a new class of amphiphilic calix[ 4] arene-based ionophores, relying on direct reductive amination as a key step, and the evaluation of their H+ and Na+ transporting properties is described.