Chitosan nanoparticles as delivery systems for doxorubicin.

The aim of this paper was to evaluate the potential of chitosan nanoparticles as carriers for the anthracycline drug, doxorubicin (DOX). The challenge was to entrap a cationic, hydrophilic molecule into nanoparticles formed by ionic gelation of the positively charged polysaccharide chitosan. To achieve this objective, we attempted to mask the positive charge of DOX by complexing it with the polyanion, dextran sulfate. This modification doubled DOX encapsulation efficiency relative to controls and enabled real loadings up to 4.0 wt.% DOX. Separately, we investigated the possibility of forming a complex between chitosan and DOX prior to the formation of the particles. Despite the low complexation efficiency, no dissociation of the complex was observed upon formation of the nanoparticles. Fluorimetric analysis of the drug released in vitro showed an initial release phase, the intensity of which was dependent on the association mode, followed by a very slow release. The evaluation of the activity of DOX-loaded nanoparticles in cell cultures indicated that those containing dextran sulfate were able to maintain cytostatic activity relative to free DOX, while DOX complexed to chitosan before nanoparticle formation showed slightly decreased activity. Additionally, confocal studies showed that DOX was not released in the cell culture medium but entered the cells while remaining associated to the nanoparticles. In conclusion, these preliminary studies showed the feasibility of chitosan nanoparticles to entrap the basic drug DOX and to deliver it into the cells in its active form.

[Malignant systemic mastocytosis (author's transl)]. / Mastocytose systémique maligne.

The case of a 37 year old man with systemic malignant cutaneous mastocytosis is reported. The outcome was fatal after eight months. Death was due to a diffuse hemorrhagic syndrome which originated in an abnormal circulating heparinoid. Nosologically, this is a border-line case between mast cell leukemia and leukemic systemic mastocytosis.

[Spontaneous pneumomediastinum in adults. 10 cases (author's transl)]. / Le pneumomédiastin spontané de l'adulte. 10 observations.

Since it is relatively rare, spontaneous pneumomediastinum is often little known to clinicians. Making the diagnosis, however, presents no problem if the three essential signs are present, that is to say: -subcutaneous emphysema of the base of the neck (7 cases), -Hamman's sign, (6 cases), -a paramediastinal air shadow on chest roentgenograms, (8 cases). The condition is brought about by rupture of perivascular alveoli resulting in the migration of air along the pulmonary vessels. The principal advantage of making the diagnosis is that it enables one to eliminate other pain-causing thoracic syndromes, especially myocardial infarction, pulmonary embolus and acute pericarditis. The clinical course is usually benign necessitating no treatment.