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.

Vertical transmission of the hepatitis C virus to infants of anti-human immunodeficiency virus-negative mothers: molecular evolution of hypervariable region 1 in prenatal and perinatal or postnatal infections.

In a prospective study of 33 infants born to hepatitis C virus (HCV)-positive human immunodeficiency virus-negative mothers the vertical transmission of HCV occurred in 6.8%. The evolution of HCV infection in two babies was studied from birth up to 5 or 6 years of age, and the sequencing of the hypervariable region (HVR) of the putative envelope-encoding E2 region of the HCV genome was performed. The HVR1 sequence variability and the different serological profiles during follow-up could reflect the differences in HCV transmission routes, HCV genotypes, and clinical evolution of infection.

[Bronchial response to a provocation test in children allergic to Dermatophagoides pteronyssinus]. / Risposta bronchiale dopo test di provocazione in bambini allergici al dermatophagoides pteronyssinus.

Bronchial provocation tests with allergens are becoming recognized as one of the most important diagnostic parameters for the detection and confirmation of the role of the allergic component directly on the reaction site. Twenty-seven children with positive skin tests and RAST for Dermatophagoides Pteronyssinus were challenged with solutions of the same antigen. Twenty-one (77%) had positive responses expressed by different patterns: Six (28.5%) showed isolated early reaction, seven (33.3%) had biphasic responses. Six (28.5%) showed dual response with prolonged (1-2 hours) late reaction. One child had dual late reaction after 35 hours (ultra-late reaction). Six (28.5%) patients had negative reactions. The results suggest that bronchial provocation tests with antigens performed as outlined in this study can also be applied in the diagnosis of pediatric allergy.

Sensitivity to tomato and peanut allergens in children monosensitized to grass pollen.

Possible associations between allergy to grass pollen and positive skin tests to food allergens were studied in 102 children monosensitized (as to inhalant allergens) to grass pollen, and in 117 children monosensitized (as to inhalant allergens) to Dermatophagoides. Thirty-two foods were tested by an epicutaneous method. Positive skin tests to food allergens were more frequent in children with allergy to grass pollen (59.8%) than in children with allergy to Dermatophagoides (9.4%). A considerably high frequency of positive reactions to tomato (39.2%), peanut (22,5%), green pea (13.7%), and wheat (11.7%) was observed in children with allergy to grass pollen. Positive skin tests to peanut closely correlated with positive RAST results and nasal provocation tests, whereas in children with skin test positivity to tomato a close correlation with nasal provocation tests but a 45% correlation with a positive RAST result were observed. RAST inhibition experiments were carried out, and the results may suggest the presence of cross-reacting IgE to grass pollen, tomato, and peanut antigens. Clinical implications of these findings are discussed in the light of histories of food hypersensitivity, urticaria-angioedema, and atopic dermatitis in children with allergy to grass pollen.

[Incidence of asthma caused by food allergy in childhood]. / Incidenza dell'asma da allergia alimentare in età pediatrica.

Both upper and lower respiratory tracts can be affected by food allergy. In infants these symptoms may be due exclusively to food allergy or may result from the effect of food allergy and another co-factor (gastro-esophageal reflux, immunodeficiency, concomitant allergy to inhalants, etc.). The incidence of food-induced asthma is not well know. In this study, using open and double blind food challenge, we found that the incidence of IgE-mediated, food-induced asthma in children is 5.7%. The most offending foods were milk, eggs, and peanuts. Food allergy respiratory symptoms were almost always associated with other clinical manifestations (cutaneous, gastrointestinal). In fact we have been able to demonstrate only one isolated case of cough due to food allergy. It follows that the recognition of food dependent-IgE-mediated asthma is essentially limited to these cases characterized by food allergy with asthmatic expression.