Photodynamic therapy (PDT) is one of a novel modalities which has recently been exploited to eradicate various microorganisms. In our study we have evaluated bactericidal efficacy of PDT in the presence of 5-δ aminolaevulinic acid (ALA). Porphyromonas gingivalis were incubated with increasing concentration of ALA and subsequently irradiated by progressive light doses. Complete killing effect was obtained for bacteria irradiated with 25J/cm2 in ALA solution final concentration of 1mM, 5mM, 10mM. Statistical analysis has revealed ALA concentration to be a major factor responsible for eradication of bacteria. The latter may be attributable to the known ALA dark toxicity.
The results of application of photodynamic diagnostics (PDD) and photodynamic therapy (PDT) for diagnosis and treatment of premalignant lesions and malignant tumours of different tissues were presented. In the period 1998-2000 a total of 314 patients were diagnosed with use of different methods of PDD and a total of 78 patients were treated with use of PDD. On the basis of obtained result we consider PDD and PDT to be sensitive, efficient and non-invasive methods of diagnostics and therapy of malignant lesions.
The efficiency of autofluorescence diagnosis within urinary bladder was analyzed in the study. We examined two groups of patients: the first one consisting of 22 patients suspected to have bladder cancer and the second one consisting of 45 patients who have undergone transurethral electro resection due to urinary bladder neoplasms. Our goal was to detect cancerous tissue invisible in white-light examination. In the first group sensitivity was 100 percent and specificity was 69.23 percent. In the second group sensitivity was 96 percent and specificity was 80 percent. We also report in the study treatment efficiency of PDT in 12 patients with superficial bladder cancer. In our procedure two hours after the instillation of bladder with ALA solution, the lesion was irradiated by laser light. In 9 out of 12 treated patients regression of bladder tumor was obtained, while in 3 cases a progression of neoplasmatic process was observed.
110 patients were subjected to colonscopy under white light and autofluorescence. An adapted Xillix LIFE system and xenon light source with interference filter were used in the autofluorescence diagnostics. Both techniques revealed 67 small lesions, including 45 neoplastic ones and 22 others in the examined patients. The autofluorescence examination revealed 43 neoplastic changes, while conventional white-light colonscopy allowed for localization of 39 neoplastic lesions. Autofluorescent imaging of large intestine mucosa is more sensitive in the detection of small neoplastic changes than traditional colonscopy.
Mitochondria constitute well-established target for photodynamic action provided that duration of incubation time with hydrophobic photosensitizer is long enough (18 - 24 hrs) to enable incorporation of the dye into these organelles. It was found that 1 hour incubation of rat cardiocytes with hematoporphyrin dihydrochloride (Hp) followed by low-energy HeNe laser irradiation (ED: 0.3, 1.0, or 3.0 J/cm2), affected mitochondrial membrane potential. The latter was monitored by means of the fast-response fluorescent probe DASPMI and the dynamic video imaging system equipped with frame-grabbing and analyzing software. The time-course of mitochondrial membrane potential decrease exhibited dependence on both: Hp concentration and ED used. In cells incubated with 1 (mu) g/ml Hp a decrease of DASPMI fluorescence occurred during 8 - 15 mins and was preceded by oscillations of fluorescence intensity. For cells incubated with 100 (mu) g/ml Hp disappearance of discrete pattern of mitochondrial fluorescence was observed 1 - 2 mins after irradiation.
Sodium pump (Na+/K+-ATP-ase) utilizing energy accumulated in macroergic bonds of ATP, maintains physiological sodium and potassium gradients across plasma membrane. This, in turn, preserves cell volume and enables functioning of all Na+-gradient driven cotransporters and exchangers. Therefore, any impairment of Na+/K+-ATP-ase activity results in severe consequences to cell viability. Cardiac cells are equipped with efficient enzymatic machinery capable of coping with oxidative stress. This was the rationale for examining their sodium pump activity upon photosensitization. Cells were incubated with hematoporphyrin dihydrochloride for 1 hour and irradiated using HeNe low-energy laser light (ED: 0.1, 0.3 or 1.0 J/cm2). It was found that Na+/K+-ATP-ase activity in 3-day-old cardiocytes is indirectly stimulated during photosensitization by rapid influx of sodium. The latter was determined by radiometric fluorescent probe SBFI/AM. Five-day-old cardiocytes turned out to be less resistant to photo-oxidative stress as the pump activity was inhibited by 50% in comparison to control cells.
Low energy laser irradiation has an effect on Nerve Growth Factor and anti mitotic factors release from rat and mouse skeletal muscle cultures. It was found that there is a transient elevation of intracellular calcium in the myotubes immediately after irradiation. Calcium changes were detected by dynamic video imaging systems and with a photometric system. Pre incubation of the myotubes with photosensitizers enhance the elevation of both cytosolic calcium and cytokines release from the cells after Helium/Neon irradiation with energy of 3-10 J/cm2. These findings can lead to an hypothesis that transient changes in calcium can accelerate cytokines release from the myotubes.
In this paper the authors present their own experience in lasertherapy of motional system overloading syndromes in 522 patients, in which laser radiation was used as monotherapy. IR semiconductor lasers and He-Ne laser were used. Each irradiation procedure was performed in 2 stages: 1) the scan of painful region; 2) irradiation of trigger points. As a result of 10-25 irradiations the improvement was obtained in 61-87 percent of patients and it was significantly better as compared to the control group in which sham-irradiation was made. On the basis of obtained results one may conclude that lasertherapy is a very useful, assisting method in treatment of motional system overloading syndromes. The therapeutical effects of the method are related to analgesic and antiphlogistic action of laser radiation.
It has been found that low power lasers in the visible and near IR cause biostimulation of injured tissues. We therefore studied the effect of a light source in the visible, HeNe, 633nm, and near IR 780nm, on fibroblast proliferation. We found that at certain low energy doses there is an enhancement in their proliferation. As intracellular Ca2+ movements play a vital role in cell proliferation, we measured intracellular Ca2+ concentration variations in irradiated fibroblasts by using a dynamic fibroblast proliferation also change intracellular Ca2+ concentration in these cells.
The effect of infrared laser radiation on specific electrical conductivity and relative permittivity of blood in experimental animals was estimated. The experiment was carried out on 30 male guinea pigs weighing 280 - 320 g. Fifteen animals composed a group irradiated with laser, the other 15 animals made up a control group in which no irradiation was made. A semiconductive laser generating infrared radiation (wavelength -- 904 nm, frequency -- 800 Hz, pulse duration -- 200 ns, mean power -- 8.7 mW) was used. The right infracostal region of the animal was irradiated 3 minutes daily for 15 consecutive days. After the end of the experiment in the obtained blood the values of impedance and phase shift angle were measured by means of impedancemeters in the frequency range from 100 to 10,000 kHz. The values of specific electrical conductivity and relative permittivity were calculated on the basis of obtained data. A distinct increase of specific electrical conductivity and decrease of relative permittivity were obtained in the blood of irradiated animals at all frequencies, as compared to the controls. No changes in relaxation frequency were noticed between both groups. On the basis of obtained data it is possible to confirm a distinct effect of low-energy laser radiation on dielectric properties of blood in experimental animals. Since the observed changes in (chi) and (epsilon) ' occurred in (beta) -dispersion region, they might therefore be attributed to the charging of cell membranes in erythrocytes.
The effect of infrared laser radiation on viscosity of serum and blood in experimental animals was investigated. The experiment was carried out on 30 male guinea pigs weighing 280 - 320 g. Fifteen animals composed a group irradiated with laser, the other 15 animals made up a control group in which no irradiation was made. A semiconductive laser generating infrared radiation (wavelength -- 904 nm, frequency -- 800 Hz, pulse duration -- 200 ns, mean power - - 8.7 mW) was used. The right infracostal region of the animal was irradiated 3 minutes daily for 15 consecutive days. After the end of the experiment in the obtained blood and serum the measurement of hematocrit and rheologic examination was made in the temperature of 310 K. The estimation of viscosity of whole blood was made by means of low-gradient viscosimeter `low shear,' for shearing velocities: D1 equals 0.116 s-1 and D2 equals 4.59 s-1. The viscosity of serum was estimated using Ubbelohd's microviscosimeter. A significant increase of whole blood viscosity measured for shearing velocity D1 was obtained in irradiated animals as compared to the controls. No statistically significant differences in viscosity of whole blood at clotting speed D2, viscosity of serum and hematocrit were observed between both groups of animals. The obtained data prove a distinct effect of low-energy laser radiation on rheologic properties of blood in experimental animals. The increase of whole blood viscosity, observed only at low shearing velocities, is probably related to the changes of structural and functional properties of cell membranes of erythrocytes resulting in a decrease of aggregation.
It was observed in some experiments that visible laser radiation activates the enzymatic function of mitochondria, while infrared laser radiation affects the enzymatic activity of cellular membranes. The aim of the study was to estimate the activity of some membranous as well as mitochondrial enzymes of hepatocytes in rats irradiated with infrared laser. Experimental material consisted of 38 Wistar rats divided into 2 groups -- a studied group exposed to infrared laser radiation and a control group, in which no irradiation was made. A semiconductive infrared laser (wavelength -- 904 nm, mean power -- 8.9 mW) was used. The clean-shaven skin of the right infracostal region of animals was irradiated 5 minutes daily for 15 consecutive days. After finishing the experiment in the preparations from obtained segments of the left liver lobe, the enzymatic activity of succinate dehydrogenase (SDH, EC 1.3.99.1), lactic dehydrogenase (LDH, EC 1.1.1.27), Mg2+ dependent ATP-ase (ATP-ase Mg2+, EC 3.1.3.2.) and acid phosphatase (AcP, EC 3.6.1.8.) was estimated with the use of histochemical methods. In the case of SDH and LDH the increase of enzymatic activity was observed in all 3 zones of liver cluster, especially in male rats. In the case of ATP-ase Mg2+ and AcP the increase of enzymatic activity in biliary canaliculi of hepatocytes in all zones of the liver cluster was observed. On the basis of the obtained results it was proved that infrared laser radiation activates significantly the enzymatic activity of most of the analyzed enzymes, which means that it affects not only properties of biological membranes but also activates the oxidoreductive processes of organism, as it has been observed for visible laser radiation. On the basis of the spectrum of energetic levels in macromolecules (Jablonski's diagram) the mechanisms of availed results are discussed both for enzymes possessing and not possessing chromatophores.
The neutrophil is the cell in which phagocyting and transforming of some exogeneous agents results in marked stimulation of nonmitochondrial respiratory chain activity (respiratory burst). In our experiment we focused on determining the level of chemiluminescence (CL) of stimulated neurotrophils during and after irradiation, measuring the photon emission intensity in 6 second's intervals. We used Ga-Al-As pulsed laser (wavelength 904 nm, mean power 8,9 mW, Alpha-Electronics GmbH, Germany) which was placed over the tube containing the suspension of guinea pig peritoneal neurotrophils (2X106 cells/ml). The sensitivity range of used photomultiplier (9514s, THORN EMI, Middlesex, England) was 300-600 nm, which allowed us to measure the CL of neutrophils while being irradiated. The neutrophils were stimulated by phorbol myristate acetate (PMA) and CL intensified by luminol. The decay of luminol-dependent CL of neutrophils may be described by hyperbolic function curve. We switched the laser radiation on for 20 s, 60 s and 300 s and each time we observed the same reaction: the about 20% decrease of intensity of CL immediately after beginning the irradiation. The CL remained on decreased level during the whole period of irradiation reaching immediately the level of CL intensity characteristic for decay curve (20% increase), just after switching off the laser. Only after the longest irradiation time (300 s) we observed CL being higher and inconsistent with decay curve for several minutes. The type of reaction was always the same, regardless to the point of CL decay curve at which laser radiation was applied. The same changes of Cl we obtained irradiating the enzymatic system: horseradish peroxidase (HRP)-luminol - H2O2.
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