The laser radiation action on the biological objects

The basic physical mechanisms of laser influence on living tissues are discussed. The role of radiation monochromaticity, self-organising and non-equilibrium of laser influence, intravenous blood photomodification of and others is considered. Laser anesthesia and antistress influence is discussed. It is experimentally confirmed biological substances solution manoclusterization under the influence of laser radiation.     

Doppler spectroscopy of blood in vivo under the action of low-intensity laser radiation

The rate of microcirculation of blood in human skin is studied in vivo in the normal state and in the presence of cardiovascular diseases. It is shown experimentally that low-intensity laser radiation affects the rheological characteristics of erythrocytes. To explain the results obtained, a model for calculating the heating of blood in capillaries under the action of low-intensity laser radiation is proposed.     

On the mechanisms of interaction of low-intensity millimeter waves with biological objects

The interaction of low-intensity millimeter-band electromagnetic waves with biological objects is examined. These waves are widely used in medical practice as a means of physiotherapy for the treatment of various human disorders. Principal attention is given to the mechanisms through which millimeter waves act on the human organism.Institute of Radio Engineering and Electronics, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 1, pp. 30–41, January, 1994.     

A refined diffusion model of the interaction of laser radiation with biological tissue

A refined diffusion model of laser radiation propagation in a highly scattering medium that, in contrast to the conventional variant, takes into account the initial single directivity of the photon source is presented. The two variants of the diffusion model are numerically compared. For small thicknesses of the scattering layer, the refined model is shown to be more accurate than the classical model.     

Assessment of the therapeutic action of low-intensity laser radiation from the extent of local tissue saturation with oxygen

We propose a method for dosimetry of the biological response to laser irradiation based on determination of the amount of oxygen additionally supplied to the tissue. We show that it is feasible to determine the therapeutic dose from the change in the degree of oxygen saturation of the blood, heart rate, hemoglobin concentration in the blood, and exposure time. __________ 13Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 4, pp. 516–520, July–August, 2006.     

Biophotonics of the interaction of low-intensity laser radiation with blood erythrocytes

We have studied experimentally how optical radiation affects the neutralization of the toxic action of heavy metals and harmful chemical compounds (ecotoxicants) on the oxygen-transport function of blood erythrocytes. It has been found that the optical radiation has a stabilizing effect and prevents lowering the erythrocyte concentration in the presence of phenol and heavy metals in blood. We have studied the neutralization efficiency of the toxic action of ecotoxicants in relation to the laser irradiation time. The obtained data on the effect of the laser radiation on the thermal denaturation of hemoglobin and erythrocytes yield the scientific substantiation to the development of the optical method for the use in medicine upon drawing and conserving donor blood. We have shown that the obtained data can be used in medicine for improving the reliability of conditions of conservation and storage of donor blood, as well as for preventing the toxic action of harmful chemical compounds in the environment.     

Kinetics of oxygenation of skin tissue exposed to low-intensity laser radiation

We present the results of modeling the action spectrum and an experimental investigation of the effect of laser-induced photodissociation of oxyhemoglobin in vivo on the increase in the degree of oxygenation of skin tissue in the exposed area. We have shown that controlling the local concentration of free molecular oxygen in biological tissues together with the possibility of eliminating tissue hypoxia using laser radiation makes it possible to stimulate aerobic cell metabolism and to achieve the needed therapeutic effect. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 120–125, January–February, 2007.     

A mathematical model of the photodynamic fullerene-oxygen action on biological tissues

A kinetic model of the photodynamic fullerene-oxygen action on biological tissues is developed. The efficiency of generation of singlet oxygen is studied in relation to the intensity of exciting radiation and the concentrations of fullerene and oxygen. The spectral efficiencies of singlet oxygen generation upon irradiation of a biological tissue by a lamp and different lasers are studied and compared with each other. The power of luminescence of singlet oxygen is calculated. The spatial distributions of singlet oxygen in allantoic fluid and in murine sarcoma are studied. The oxidation of lipids of external membranes is assumed to be the basic mechanism of cell damage. The characteristic time of this oxidation is calculated. The dose curve of cell survival is estimated. The results of modeling are compared with experimental data in the literature.     

Effect of exposure of sturgeon roe to low-intensity laser radiation on the hardiness of juvenile sturgeon

We present data on the effect of polarized laser radiation in the near IR region of the spectrum with wavelength 808 nm on the resistance of juvenile sturgeon to oxygen deficiency in the habitat when the fertilized roe are briefly exposed to radiation in the organogenesis stage. The magnitude of the stimulating effect depends on the exposure time (t) and power density (P) of the radiation and also on its modulation frequency (F). For optimal irradiation parameters (cw mode, P = 2.9 mW/cm², t = 60 sec), the hardiness of the juveniles increases by a factor of ∼1.5 compared with the control group. The maximum differences in the sensitivity of embryos to cw and pulsed radiation are observed for F = 1 Hz; as the modulation frequency increases up to F = 50 Hz, the magnitude of the photobiological effect approaches a level typical for cw exposure. We show that the duration of the dark period (pause time) between pulses is the critical parameter determining the dependence of the stimulating effect on the modulation frequency. We discuss questions concerning use of the indicated physical factor in the technology for raising sturgeon under industrial fish farming conditions. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 2, pp. 233–241, March–April, 2008.     

The simulation of the interaction between low-intensity laser beams and multilayer scattering biological materials

A mathematical model of interaction between low-intensity laser radiation and multilayer biological materials with allowance for scattering is put forward. Within this model, the intensity distribution during the laser irradiation is found by the Monte Carlo method and the temperature field in the biological tissue, by the method of adaptive finite elements that automatically generates an optimal element grid.     

Scattering of laser radiation by multifractal biological structures

Scattering of laser radiation by structured biotissues—histological mounts of bony and muscular tissues and skin, are studied.     

Numerical modeling of the action of pulse laser radiation on small absorbing targets

The features of acoustic wave generation in a dense medium due to the absorption of laser pulse radiation were analyzed numerically, based on solutions to the equations of motion in Lagrange form. The influence of thermal and acoustic mechanisms in changes of physical parameters in a dense medium was studied over a wide range of temporal and energetic characteristics typical of laser systems.