GdDOTAGA(C18)2: an efficient amphiphilic Gd(iii) chelate for the preparation of self-assembled high relaxivity MRI nanoprobes.

A new amphiphilic GdDOTA-like complex functionalized with two octadecyl chains was synthesised and incorporated into the bilayer of liposomes and dendrimersomes. (1)H NMR relaxometric studies and in vivo MRI experiments on mice bearing a syngeneic melanoma tumour have shown a great improvement in performance.

Novel stable dendrimersome formulation for safe bioimaging applications.

Dendrimersomes are nanosized vesicles constituted by amphiphilic Janus dendrimers (JDs), which have been recently proposed as innovative nanocarriers for biomedical applications. Recently, we have demonstrated that dendrimersomes self-assembled from (3,5)12G1-PE-BMPA-G2-(OH)8 dendrimers can be successfully loaded with hydrophilic and amphiphilic imaging contrast agents. Here, we present two newly synthesized low generation isomeric JDs: JDG0G1(3,5) and JDG0G1(3,4). Though less branched than the above-cited dendrimers, they retain the ability to form self-assembled, almost monodisperse vesicular nanoparticles. This contribution reports on the characterization of such nanovesicles loaded with the clinically approved MRI probe Gadoteridol and the comparison with the related nanoparticles assembled from more branched dendrimers. Special emphasis was given to the in vitro stability test of the systems in biologically relevant media, complemented by preliminary in vivo data about blood circulation lifetime collected from healthy mice. The results point to very promising safety and stability profiles of the nanovesicles, in particular for those made of JDG0G1(3,5), whose spontaneous self-organization in water gives rise to a homogeneous suspension. Importantly, the blood lifetimes of these systems are comparable to those of standard liposomes. By virtue of the reported results, the herein presented nanovesicles augur well for future use in a variety of biomedical applications.

In Vivo MR Imaging of Fibrin in a Neuroblastoma Tumor Model by Means of a Targeting Gd-Containing Peptide.

PURPOSE: A magnetic resonance imaging contrast agent based on a tetrameric Gd-DTPA-like system linked to a fibrin-targeting peptide (Gd-F) has been designed for in vivo tumor characterization. PROCEDURES: Gd-F was synthesized following Fmoc-SPPS strategy. Binding was measured using soluble fibrin DD(E) fragment and a dried fibrin assay. Contrast efficiency was tested on human and mouse clots and in vivo on Neuro2A tumor model. An anti-thrombotic drug was used to evaluate Gd-F sensitivity for changes in fibrin availability at the tumor site. RESULTS: The high relaxivity of Gd-F (42 mM(-1) s(-1), per molecule) yielded a strong signal enhancement in human and murine clots. High contrast was also measured in vivo in Neuro2A tumors, with a persistent enhancement in tumor rim and stroma. Upon treatment with an anti-thrombotic drug, the contrast uptake was significantly reduced in the tumor area confirming the specificity of the probe. CONCLUSIONS: Gd-F resulted to be an efficient probe for tumor delineation and for monitoring fibrin deposits during tumor progression and anti-thrombotic therapy.

Twice-weekly pegylated interferon-α-2a and ribavirin results in superior viral kinetics in HIV/hepatitis C virus co-infected patients compared to standard therapy.

BACKGROUND: Hepatitis C virus (HCV)/HIV co-infected patients have more rapid progression of liver fibrosis and only modest cure rates (sustained virologic responses, SVRs) when compared to HCV monoinfected patients. METHOD: We compared the virologic responses of either twice-weekly peginterferon-α-2a 180 µg/week (for 4 weeks, followed by weekly dosing) or weekly peginterferon-α-2a 180 µg/week, and weight-based ribavirin (1-1.2 g/day), among HIV/HCV co-infected genotype-1 individuals. RESULTS: Patients receiving the investigational dosing had lower levels of HCV RNA at all time points after initiation of therapy. More patients on this arm achieved clinically relevant early virological responses at weeks 1, 2, 4, 12, and 24. The enhanced early virologic response observed with the investigational arm was associated with a higher induction of interferon-stimulated genes. This early double dose regimen also resulted in a rapid normalization of liver enzymes. Twice-weekly peginterferon-α-2a was associated with more frequent early virological responses with similar safety profiles when compared with standard therapy. CONCLUSION: Our results, when confirmed in larger randomized clinical trials, may provide a novel therapeutic approach to improve SVR among HIV/HCV co-infected patients, especially African-American patients.

Copper(II)-selective membrane electrodes based on some recently synthesized mixed aza-thioether crowns containing a 1,10-phenanthroline sub-unit.

Three different mixed aza-thioether crowns containing a 1,10-phenanthroline sub-unit were investigated to characterize their abilities as copper(II) ion carriers in PVC-membrane electrodes. The electrode based on L1 exhibited a Nernstian response for Cu(2+) ions over a wide concentration range (2x10(-1) to 1x10(-5) M) with a limit of detection of 8.0x10(-6) M (0.5 p.p.m.). The response time of sensor is 15 s, and the membrane can be used for more than 3 months without observing any deviation. The electrode revealed comparatively good selectivities with respect to many alkali, alkaline earth, transition and heavy metal ions, and could be used in a pH range of 2.5-5.5. It was applied to the direct determination and potentiometric titration of the copper(II) ion.