RESUMEN
The use of manganese bacteriopheophorbide characterized by a high relaxation capacity and selectively accumulating in the tumor as a contrast agent for magnetic resonance tomography significantly improves tumor contrasting against the background of normal tissues. The pharmacokinetics and selectivity of accumulation were studied by diffuse reflection spectroscopy.
Asunto(s)
Bacterioclorofilas/química , Medios de Contraste/química , Imagen por Resonancia Magnética/métodos , Compuestos de Manganeso/química , Animales , Bacterioclorofilas/farmacocinética , Carcinoma de Ehrlich/diagnóstico por imagen , Carcinoma de Ehrlich/metabolismo , Carcinoma de Ehrlich/patología , Medios de Contraste/farmacocinética , Compuestos de Manganeso/farmacocinética , Ratones , Ratones Desnudos , CintigrafíaRESUMEN
The subject of the paper is study of optical absorption of sensitizers in biological tissue. The study shows that absorbance can be used as a tool that allows studying biodistribution of sensitizers and their interaction with tissue in vivo. The article presents a simple technique of determining biological tissue absorption in vivo, and discusses the results of experimental animal studies of some sensitizers.
Asunto(s)
Modelos Biológicos , Fármacos Sensibilizantes a Radiaciones/farmacología , Análisis Espectral/instrumentación , Tomografía de Coherencia Óptica/métodos , Diseño de Equipo , Fluorescencia , Humanos , Imagen por Resonancia Magnética , Fármacos Sensibilizantes a Radiaciones/administración & dosificaciónRESUMEN
A simple method to evaluate the hemoglobin oxygen saturation and relative hemoglobin concentration in a tissue from diffuse reflectance spectra in the visible wavelength range is put forward in this paper. It was assumed that while oxygenated and deoxygenated hemoglobin contributions to light attenuation are strongly variable functions of wavelength, all other contributions to the attenuation including scattering are smooth wavelength functions and can be approximated by Taylor series expansion. Based on this assumption, a simple, robust algorithm suitable for real time monitoring of the hemoglobin oxygen saturation in the tissue has been derived. This algorithm can be used with different fiber probe configurations for delivering and collecting light passed through the tissue. An experimental technique using this algorithm has been developed for in vivo monitoring during artery occlusion and in vitro monitoring of blood samples. The experimental results obtained are presented in the paper.
Asunto(s)
Sangre/metabolismo , Hemoglobinas/metabolismo , Oxígeno/metabolismo , Absorción , Algoritmos , Animales , Humanos , Fantasmas de Imagen , Análisis Espectral/métodos , Factores de TiempoRESUMEN
Comparative studies of oxygen consumption, changes of photosensitizer fluorescence, and photodestruction of erythrocytes, and photodestruction of oxygen transport protein hemoglobin were performed during photodynamic reaction in whole and hemolyzed blood with phthalocyanines, chlorines, porphyrins, and methylene blue photosensitizers in vitro and in selected cases in vivo. The present work deals with the investigation of blood oxygen saturation SO2 and photosensitizer fluorescence during and immediately after light irradiation in the photodynamic therapy process. It has been observed that SO2 behavior strongly correlates with the type of photosensitizer. The decrease of photosensitizer fluorescence (photobleaching) during light irradiation can be followed by the recovery of the photosensitizer fluorescence immediately after interruption of the irradiation within 6-8 min. The levels of photodestruction of erythrocytes in whole blood and photodestruction of hemoglobin in hemolyzed blood in combination with the above photosensitizers reveal the influence of photodynamic reactions upon the ability of blood to transport oxygen. Maximal photohemolysis activity has been found with chlorine p6 photosensitizers.