Structure and size of spontaneously formed aggregates in Aerosol OT/PEG mixtures: effects of polymer size and composition.

Dynamic light scattering and Cryo-TEM measurements have allowed us to obtain the size and structure of spontaneous aggregates formed by mixtures of Aerosol OT, AOT, and ethylene glycol polymers of different molecular mass. The results presented in this work show that small unilamellar vesicles predominate in pure Aerosol OT solutions and in dilute polymer solutions mixed with AOT. In the latter case, elongated micelles coexist with unilamellar vesicles. When polymer concentration increases above a certain concentration, the small vesicles disappear and the size of the elongated micelles decreases to a radius compatible with spherical micelles. For PEG concentrations above the overlapping ones, spherical micelles coexist with very large aggregates probably formed by large rod like micelles or by superstructures of elongated micelles embedded in a polymer network. This behavior is consistent with theoretical models based in molecular mean-field theory [M. Rovira-Bru, D.H. Thompson, I. Szleifer, Biophys. J. 83 (2002) 2419]. The properties of the different types of aggregates are obtained by fluorescence spectroscopy and electrophoretic mobility measurements.

[Extramedullary plasmacytoma of the head and neck. Report of 3 clinical cases]. / Plasmocitoma extramedular de cabeza y cuello. Presentación de 3 casos clínicos.

Plasmocytomas are neoplasic disorders arising from plasma cells that include Multiple Myeloma (MM) Solitary Plasmocytoma of the bone and Extramedullary Plasmacytoma (EMP). EMP are solitary tumours consisting of plasma cell proliferation that occurs in locations other than bone. A variable percentage may be associated at a later date with the development of MM. EMP represent up to 4% of nonepithelial tumours of the upper respiratory tract. They generally occur in the submucosal tissue of the upper airways (80% of cases), with a predilection for nasopharynx, nasal cavity, paranasal sinuses and tonsils. We report 3 cases of Extramedullary Plasmocytoma located one in the upper respiratory tract. All the patients underwent surgical resection or biopsy of the lesion that allowed the histological study, which showed a plasma cell proliferation. Serum and bone marrow studies conclude the diagnosis of Extramedullary Plasmocytoma. The treatment was radiotherapy, with or without previously surgery. Three patients are currently under close follow-up and no evidence of recurrence has been found. We review the clinic, diagnostic, therapeutic and prognostic aspects of this kind of tumours.