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.

Primary retroperitoneal teratoma in the adult: correlation of MRI features with CT and pathology.

Primary benign teratoma of the retroperitoneum is a rare tumor in the adult population. Only one case with an MRI examination has been reported in the English literature. This paper describes the CT and MRI features of a retroperitoneal teratoma in a 24-year-old male and discusses the value of MRI in the diagnosis and the preoperative imaging of such a tumor.

Gd-DOTA: evaluation of its renal tolerance in patients with chronic renal failure.

Gd-DOTA is an intravenous contrast medium used in MRI. The clinical and biological tolerance of Gd-DOTA was studied in patients with chronic renal failure (e.g., those having a glomerular filtration rate of less than 60 mL/min). Twenty patients were randomized into two groups. In the control group, spin-echo (SE) T1- and T2-weighted images of the kidneys were obtained without injection of Gd-DOTA. In the DOTA-group, patients received 0.1 mmol/kg of Gd-DOTA. SE T1-weighted images were obtained before and after injections; a T2-weighted sequence was performed before injection. Clinical data, serum creatinine, and laboratory parameters were estimated before, and 24 and 48 hr after MRI. No adverse reaction was reported after injection of Gd-DOTA. Mean serum creatinine and glomerular filtration rate remained unchanged in both groups. For five patients in the control group and three patients in the DOTA-group the serum creatinine levels increased more than 10% and less than 25%. No evidence of nephrotoxicity was observed with Gd-DOTA in patients with chronic renal failure.

[Intramural hematoma of the duodenum following acute pancreatitis. X-ray computed tomographic aspect of a case]. / Hématome intra-mural du duodénum consécutif à une pancréatite aiguë. Aspect scanographique d'un cas.

Intramural hematomas of the duodenum in adults most often have a traumatic cause, but they may also be a complication of acute alcoholic pancreatitis. The diagnosis is based on the CT appearance. Treatment is usually medical. Surgery is necessary in case of recurrence or of a major hemorrhagic syndrome.

MR imaging of adult Wilms' tumor: correlation with US, CT, and pathology.

The magnetic resonance (MR) features of an adult nephroblastoma are presented. The MR appearance is correlated with ultrasound (US), computed tomographic (CT) and pathology. The tumor appeared heterogeneous with calcifications and areas of necrosis and hemorrhage. MR correctly staged the tumor.