Nitroxide radicals. Controlled release from and transport through biomimetic and hollow fibre membranes.

Stable nitroxide radicals have found wide applications in chemistry and biology and they have some potential applications in medicine due to their antioxidant properties. Nitrocellulose filters impregnated with lipid-like substances are used as an imitation of biomembranes and could be used as a controlled drug release vehicle, while experiments with hollow fibres can be useful in the modelling of a drug delivery via blood vessels. This paper describes mechanisms of the nitroxide transport in four different model systems, i.e. a) exit of nitroxide into aqueous solution from porous nitrocellulose filters, impregnated with organic solvents, b) transport of nitroxides through the impregnated membrane from one into another aqueous solution, c) transport of nitroxides from bulk phase of organic solvents through the impregnated membrane into aqueous phase with ascorbic acid, and d) transport of nitroxides from liquid organic phase into aqueous solution through porous hollow fibres. The results are analysed in terms of mass transfer resistance of a membrane, organic and aqueous phase, based on nitroxide diffusion and distribution coefficients. Ascorbic acid reduced nitroxides in water and enhanced the rate of their transfer due to the decrease of transport resistance of unstirred aqueous layers. It is demonstrated that in the case of biomembranes the rate limiting step could be the transport through unstirred aqueous layers and membrane/water interface.

[Radiologic diagnosis of non-Hodgkin's lymphoma in abdominal and retroperitoneal sites]. / Luchevaia diagnostika nekhodzhkinskikh limfom abdominal'noi i retroperitoneal'noi lokalizatsii.

A total of 112 patients with non-Hodgkin's lymphomas of abdominal and retroperitoneal localization were examined by the ultrasonic and x-ray methods, in 83 of them x-ray computer-aided tomography was used. Angiographic examinations and puncture biopsy monitored by US or x-ray CAT were carried out if indicated. The authors discuss the problems of ultrasonic and x-ray semeiotics of the lymphomatous involvement of the lymph nodes, spleen, gastrointestinal tract. They claim that USE, permitting the specification of further plan of examination of each patient, and x-ray examination as a method to assess the gastrointestinal status are the optimal methods for the primary diagnosis of non-Hodgkin's lymphomas. US data may prompt further application of x-ray CAT, whose results will supplement the US findings. Angiographic examinations should be carried out only in the most difficult diagnostic situations, bearing in mind the invasive nature of the method and its high price.