The study of the functional morphology of rat sarcoma M-1 after photodynamic therapy using bacteriopurpurinimide disulfide derivative (disulfide-BPI) as a photosensitizer is described. The research methods included immunohistochemistry for PCNA and CD31, evaluation of mitotic activity and apoptosis of tumor cells, as well as computer analysis of microscopic images. Photoinduced antitumor effect was shown to be due to the destruction of sarcoma M-1 vascular bed, the rapid inhibition of proliferative activity and devitalization of tumor cells by apoptosis and necrosis. It is reasonable to suppose that in the early stages after photodynamic therapy destruction of the microvasculature and photocytostatic shock of tumor cells with subsequent development of necrosis are caused by direct influence of the light flux on sensitized cellular elements in parenchyma and stroma of tumors. The efficiency of photodynamic therapy with the novel photosensitizer is determined by the sequence of destructive and inflammatory changes in tumor parenchyma and surrounding tissues, as well as repopulation potential of tumor cells survived after treatment.

The results of the pilot study of combined treatment for non-resectable cholangiocarcinoma complicated with obstructive jaundice are represented this paper. Method included percutaneous transhepatic biliary drainage, endoscopic fluorescence diagnosis, photodynamic therapy of tumor stricture, and stenting of bile ducts. Fourteen patients who underwent the treatment in the surgery department clinic of I.M. Sechenov First Moscow State Medical University were enrolled in the study. Fluorescence diagnosis and photodynamic therapy were carried out using photosensitizers photosens (0.5 mg/kg), fotolon (1 mg/kg), and radachlorin (1 mg/kg). The average light dose for one session was 115±5 J/cm2. Fluorescence diagnosis using endoscopic video-fluorescence system for endoscopy and minimally invasive surgery allowed to obtain videoassisted fluorescence image of the tumor and to measure level of photosensitizer fluorescence in tumor in all patients. Malignant tumor was confirmed by morphological study in 12 patients, biopsy of material for morphological study failed in 2 patients with Klatskin tumor. The preliminary results of combined minimally invasive treatment were assessed as promising. The survival time in 4 patients after treatment accounted for 21, 17, 13 and 11 months, respectively. For now 5 patients are under follow-up. Follow-up periods are 13 and 19 months in 2 of them and from 4 to 6 months in 3 of them. Five patients with multiple distant metastases before the treatment died in 3±1 months after therapy. The average lifetime in the treatment group is 9.5 months up to date, however the duration is expected to be

longer because 5 of 14 patients are alive.

The results of the study of subcellular distribution of molecular meso-tetra(3-pyridyl)bacteriochlorin nanocrystals proposed as therapeutic agents for photodynamic therapy are represented in the article. Investigations and measurement of spectroscopic properties of molecular crystals of near-infrared photosensitizer were conducted using special device complex based on fiber-optic spectrometer. Investigation and analysis of the pattern of subcellular accumulation of meso-tetra(3-pyridyl)bacteriochlorin in molecular (dimethyl sulfoxide (DMSO) as solvent) and nanocrystalline forms on different cell lines: human monocytes (THP-1), human cervical cancer cells (HeLa) and mouse malignant brain tumor cells (glioma C6). The dynamics of subcellylar accumulation of the agent at concentration of 5 and 10 mg/l was assessed with laser microscope-spectrum analyzer and by confocal microscopy. The study showed that in the course of interaction with cell lines molecular nanocrystals of the agent developed ability to fluorescence. Hence, in the cellular environment meso-tetra(3-pyridyl) bacteriochlorin nanoparticles became phototoxic giving opportunities for their use for fluorescence diagnosis and photodynamic therapy. Specific role of meso-tetra(3-pyridyl)bacteriochlorin in the range of photosensitizers is determined by its spectral characteristics, i.e. absorption and fluorescence in near-infrared band, which allows measuring and affecting on deeper layers of biotissue. Thus, the use of meso-tetra(3-pyridyl)bacteriochlorin nanoparticles as nanophotosensitizers may improve the efficacy of diagnosis and treatment of deep-seated tumors.

Oxygen content in body fluids and tissues is an important indicator of life support functions. A number of ocular pathologies, e.g. glaucoma, are of presumable vascular origin which means altered blood supply and oxygen circulation. Most oxygen is transported in the blood in the association with hemoglobin. When passing through the capillaries, hemoglobin releases oxygen, converting from oxygenated form to deoxygenated form. This process is accompanied by the changes in spectral characteristics of hemoglobin which result in different colors of arterial and venous blood. Photometric technique for the measurement of oxygen saturation in blood is based on the differences in light absorption by different forms of hemoglobin. The measurement of saturation is called oximetry. Pulse oximetry with assessment of tissue oxygenation is the most commonly used method in medicine. The degree of hemoglobin oxygen saturation in the eye blood vessels is the most accessible for noninvasive studies during ophthalmoscopy and informative. Numerous studies showed the importance of this parameter for the diagnosis of retinopathy of various genesis, metabolic status analysis in hyperglycemia, diagnosis and control of treatment of glaucoma and other diseases involving alterations in eye blood supply. The specific method for evaluation of oxygen concentration is the measurement of pressure of oxygen dissolved in the blood, i.e. partial pressure of oxygen. In ophthalmological practice, this parameter is measured in anterior chamber fluid evaluating oxygen level for several ophthalmopathies including different forms of glaucoma, for instillations of hypotensive eye drops as well as in vitreous body near to the optic disc under various levels of intraocular pressure. Currently, monitoring of oxygen saturation in retinal blood vessels, i.e. retinal oximetry, is well developed. This technique is based on the assessment of light absorption by blood depending on hemoglobin saturation with oxygen by analyzing spectral composition of light diffusively reflected from the retina. Oximetry of bulbar conjunctival and episcleral microvasculature can be also performed allowing for the evaluation of oxygen saturation in vessels which collect blood from the anterior segment and the characterization of anterior segment metabolism in a number of ocular pathologies and in the course of the treatment.

The results of the follow-up of the patient with persistent forehead keratoacanthoma are represented. The patient underwent one course of PDT with intralesional administration of photosensitizer radachlorin at a dose of 0.75 ml/cm2 of tumor. The characteristics of the irradiation were as follows: the laser power density 0.39 W/cm2, the light dose – 300 J/cm2. Two weeks after treatment there was a cosmetically satisfying soft normotrophic scar with no attachment to underlying tissues in the site of the treatment. According to cytological study tumor cells were not detected. For one-year follow-up there was no recurrence.