Validation of a dendron concept to tune colloidal stability, MRI relaxivity and bioelimination of functional nanoparticles.

The functionalization of spherical superparamagnetic iron oxide nanoparticles (SPION) of 10 nm with a linear monophosphonate (L1) and also PEGylated mono-phosphonated dendrons of growing generation (D2-G1, -G2 and -G3) yielded dendritic nano-objects of 15 to 30 nm in size, stable in physiological media and showing both renal and hepatobiliary elimination. The grafting of the different molecules has been confirmed by IR spectroscopy and elemental analysis. The colloidal stability of functionalized NS10 has been evaluated in water and in different physiological media. All functionalized NS10 were stable over a long period of time and displayed a mean hydrodynamic diameter smaller than 50 nm whatever the molecule architecture or dendron generation. Only the NS10@L1 showed less stability in biological media at high ionic concentration. NMRD profiles and relaxivity measurements highlighted the influence of the molecule architecture on the water diffusion close to the magnetic core thus influencing the relaxation properties at low magnetic field. Coupling of a fluorescent dye on the functionalized NS10 allowed investigating their biodistribution and highlighting urinary and hepato-biliary eliminations.

Prolactin and beta-hCG in pregnancy: 24 hour hormone profiles during preterm labour and the last 6 hours up to delivery.

We examined the 24 hour plasma profiles of prolactin and beta-hCG in 7 women with preterm labour between the 30th and 34th week of gestation. The results showed that, despite preterm labour, the circadian rhythm of prolactin was maintained. The beta-hCG levels showed a wide scattering in the normal range which is also characteristic of pregnancy with no complications. In addition we examined the prolactin and beta-hCG levels during the last 6 hours preceding delivery. Here we found significant higher hormone concentrations of hCG in the mothers delivered of female babies than in the mothers of males. This higher hormone level declined continuously during the delivery, however, without significance. We also observed concordant secretion patterns of prolactin and beta-hCG in these cases. Normal hCG and prolactin values were found in mothers delivered of male babies.

Twenty-four hours hormone secretion profiles of cortisol and estradiol in preterm labour.

We investigated the 24 hour hormone secretion profiles in women with preterm labour. Although estradiol secretion seems to be unaffected, we found an variable estradiol-cortisol-shift due to a cortisol increase. Cortisol circadian secretion persists in preterm labour, but maximum secretion is moved to midday. Further investigations are necessary to study the basic mechanisms underlying this process.