A. S. Provorov

Automated laser spectrofluorimeter for monitoring of myocardial metabolism

Methods of optical biopsy have a series of advantages before other methods of clinical diagnostics. The high accuracy of received results enables registration even small change of concentration of substances, and the opportunity of remote registration makes methods optical biopsy by an optimum means for noninvasive methods of diagnostics in medicine. The method of the fluorescent analysis allows to investigate dynamics of changes of a functional condition of organs and tissue in norm and pathologies, called by the various factors (an inflammation, ischemia, degenerative changes). Bring the results of development of expiremental setup for the laser fluorescent analysis of physiological and functional condition of various organs and tissue of organism. In expiremental setup was used pulse UF nitric laser with length of wave generation = 337 nm. For delivery of radiation to tissue, and, also, collection of a radiation of fluorescence were used various optic fiber scheme. The expiremental setup includes automated tunable monochromator and ADC, receiving a signal from photomultiplier tube. Driving of all blocks and processing of results is realize on IBM-compatible computer with the appropriate software. Was used the synchronous detecting for reducing of a background signal. Myocard at surgical introoperation by an accompanied condition of sharp ischemia was researches on these expiremental setup. Spectrofluorimetric criteria of an estimation of a condition of viscus at peritonitis were development.

Laser fluorescent method for differential diagnostics of cataract

Laser fluorescent analysis has been used for assessing the spectra of normal and nuclear cataract lens fluorescence in vivo. Spectral criterion (index of opacity) was developed for objective differentiation of cataracts stage. Contribution of ascorbic acid into spectrum of cataract lens fluorescence was analyzed.

HbCO photodissociation at the photolysing radiation wavelength range 550 - 585 nm

Assessment of carboxyhemoglobin photodissociation performed at solution of whole human blood. At the range 550-585 nm we detected maximal efficacy of carboxyhemoglobin dissociation corresponding to Q-electron transition at 570 nm.

Study of carboxyhemoglobin photodissociation with laser flash-photolysis

Assessment of the carboxyhemoglobin photodissociation has been performed under the native conditions. This investigation has a great importance for the development and creation of completely new approach for the treatment of carbon monoxide poisoning based on the photoinduced dissociation of carboxyhemoglobin. Photodissociation was registered on the experimental setup with crossing laser beams were pulsed Nd:YAG laser at the second harmonics wavelength (λ=532 nm) was used as a source of photolyzing radiation. Buffered solutions of whole human peripheral blood (PBS, pH=7.4) and diluted hemolized human peripheral blood were used. We found optimal parameters for the registration of the photodissociation such as using of buffered solutions of the whole human peripheral blood with the concentration of carboxyhemoglobin around 50% detection of dissociation of carboxyhemoglobin at the maximum of absorption within the Sorets band (435 nm). Dependence of photodissociation efficiency on the concentration of the complex in the tested solutions, as well as on the photolysis radiation intensity in both types of solutions was proved.

Waveguide pulsed gas lasers

Results of investigation of processes in waveguide pulsed gas lasers on atomic and molecular transitions are presented. Conditions of population inversion forming in N2(337 nm), XeCl, and Ne-H2(585 nm) lasers excited by longitudinal and barrier discharges in thin cells with various diameters were investigated. In the thin capillaries, significant changes of discharge forming conditions due to variation of Paschen’s curve have been observed. Particularly, in the capillaries with diameter less than 120 μm, optimal conditions of electronic temperature for the excitation of nitrogen laser at the self-breakdown have been achieved. We obtained the generation and investigated dependencies of an output power on gas pressure in the self-breakdown nitrogen laser. We studied the efficiency of XeCl excimer molecules formation in the plasma of the barrier discharge. Conditions required for efficient formation of excimer molecules in the plasma of barrier discharge was found. By double pulse technique the amplitude-frequency characteristics of efficiency of XeCl excimer molecules formation in the plasma of the barrier discharge were tested. Up to the frequency 30 kHz, there was no significant decrease of second pulse amplitude. We studied the dependence of efficiency of luminescence at the transition 3p’[1/2]0-3s’[1/2]0 of Ne (585,3 nm) on the gas pressure and the charging voltage of storage capacitors in pure Ne or with H2 additions in following ratios Ne:H2 (3:1, 2:1) with excitation by longitudinal discharge in narrow capillary 500 μm. The saturation of luminescence intensity occurs at the high pressure was found. The decreasing of luminescence at the additions of hydrogen was observed.

Laser detoxication of acute poisonings with carbon monoxide

A series of model experiments have been carried out. Those experiments have proved the fact of laser-induced photo dissociation of HbCO using Nd:YAG-laser with wavelength 533 nm at different conditions. Spontaneous reassociation of ligand to hemoproteid has been observed during the interpulse period. In order to prevent the reversibility of the reaction some oxidizing substances as well as trap-like functioning agents have been tested. The preliminary results allow us to propose the application of nonreversible laser- induced HbCO photodissotiation in the capacity of new physical method to treat acute carbon monoxide poisoning.

Effects of N2-laser radiation on the immune system cells of patients with chronic bronchitis

In spite of various investigations devoted to a problem of chronic bronchitis, many problems concerning both the reasons of the origin of this disease, and the essence of the processes, explicating in the bronchial tubes, especially on early stages of the disease, remain insufficiently studied. It makes it difficult to use an integrated approach to chronic bronchitis, that would reflect the peculiarities of its etiology, pathogenesis, its clinical course and efficiency of the therapy. During the last years the data of the clinical laboratory analysis of chronic bronchitis in connection with its immune therapy have been accumulated. In the literature there is a lot of information about the violation of immune reactions in the organism of patients, methods of the immune therapy, the data of the successful application of the intravenous laser therapy in the treatment of obstructive chronic bronchitis and bronchial asthma. However, there is no research explaining the mechanisms of the laser radiation impact on the immune status of patients suffering from chronic bronchitis. According to this it has become extremely urgent to research the mechanisms of the laser radiation impact on immune competent cells of patients suffering from chronic bronchitis.

Modification of membrane-toxic effect of Nd-YAG laser by preliminary induction of cytochrome P-450 in bone marrow cells.

The cytotoxic effects of Nd-YAG laser with a wavelength of 533 nm were studied in mouse bone marrow cells in vitro. Laser exposure caused blebbing of bone marrow cell plasma membrane. Preliminary induction of cytochrome P-450 with 3-methylcholanthrene modified the cytotoxic effect of Nd-YAG laser.

Waveguide CO2 amplifier with combined excitation

A waveguide carbon-dioxide laser amplifier with combined excitation by rf and dc discharge was investigated. Dependences of small signal gain on input rf and dc power and gas pressure are presented. A maximum gain 20.9 (DOT) 10-3 cm-1 was achieved with a pressure of 75 Torr, total input specific power about 90 W/cm3 and reduced electric field strength of 6 (DOT) 10-16 V (DOT) cm2. Conditions of keeping high gain level have been determined.

Pathophysiological aspects of laser application

The rapid growth of electrooptics and laser technology has increased the possibility of human exposure to optical radiation and concern about health effects. The much attention has to be focused on the creation of the safety program that assures the safe use of lasers taking into account the possible side effects of laser therapy. In order to investigate the imunotropic effect of lasers the experimental model which was close to the therapeutic modes has been used for IR laser (the wavelength 890 nm) and He-Ne laser (the wavelength 633 nm). The immune system underwent changes testifying about the breaches in the processes of maturation and migration of the lymphoid cells, also the alteration of receptors as a sign of the membrane damaging effect of lasers was seen.