An ultrasonic beam was focused into a biological tissue sample to modulate the laser light passing through the ultrasonic beam inside the tissue. The speckle field formed by the transmitted laser light was detected by a CCD camera with the source-synchronous-illumination lock-in technique. The ultrasound-modulated laser light reflects the local optical and mechanical properties within the ultrasonic beam and can be used for tomographic imaging of the tissue. Spatial resolution along the ultrasonic axis was achieved by sweeping the ultrasonic frequency. Two-dimensional images of biological tissue were successfully obtained with both single frequency modulation and frequency-swept modulation. Three-dimensional images could be acquired as well in principle.

Effective localization of small magnets against a noisy, real world background can involve various methods to first identify the magnetic fields produced by the magnet of interest, then to filter out background noise, and then to analyze the available magnetic field data to localize the magnet. Here we discuss low cost techniques which allow localization of small magnets with field strengths in the milliGauss range against real world background fields in the range of hundreds of mG, which may be fluctuating by up to tens of mG. Such techniques allow magnet tracking to be used to localize catheters in place of more invasive and expensive methods, e.g. fluoroscopy, for a variety of applications, including drug infusion with peripherally inserted central catheters (PICCs), laser ablation (TMR, PTMR) and introduction of pacemaker leads.

The photobleaching phenomenon has been previously first of all widely studied for exogenous photosensitizers applied in photodynamic therapy (PDT). The present paper deals with detailed investigation of photobleaching of endogenous fluorochroms in tissues in vivo during its laser irradiation at 532, 633 and 670 nm at different powers. The fluorescence decay curves during skin irradiation in vivo at these wavelengths have been obtained and analyzed. The similarity in bleaching behavior of endogenous fluorochroms and exogenous photosensitizers used in PDT gave us the reasons to imply the possible connection between native fluorochroms and low intensity laser therapy effects. The results obtained may be applied for tissue diagnostics and therapy control.

The method based on the autodyne effect in semiconductor laser has been described to the analysis of dynamical behavior of biological specimen. The advantage of the method has been shown in comparison with tradition photoelectrical methods. The experimental investigations of the effect of external alternating voltage on the amplitude and frequency of fresh water crawfish - daphnia have been implemented. The synchronization effect of daphnia heart beating by the external electric field has been discovered. The investigation results of the dependence of daphnia heart beating frequency on the water toxicity degree.

Bioelectric plant reactions induced by local low-intensity electromagnetic millimeter wavelength excitation were studied; the results are presented in this article. Plant reaction was obtained in this range where the absorption is determined by collective resonant properties of water. As a result, the previous investigations were continued and we can present the action spectrum in the range 300 nm-6mm.

In this paper, we report on the optical properties of aggregates formed by biospecific interactions like antigen/antibody, with one or both reaction components immobilized on gold particles. In the case of biospecific aggregation, the temporal changes in the absorption spectra differed from those recorded during rapid and slow salt aggregations. As in the case of rapid salt aggregation, the absorption peak decreased and shifted to the red part of the spectrum with simultaneous broadening. However, we did not observe the second red peak of the optical density. According to the transmission electron microscopy data, the slow, rapid, and biospecific aggregations resulted in small clusters with compact structures, branching aggregates of fractal type, and aggregates without direct conductive contacts of primary particles, respectively. It is supposed that the recorded differences in absorption spectra can be explained by the corresponding differences in aggregate structures. We have found a direct correlation between the amount of the second added protein initiating aggregation on the one hand, and the rate of spectral changes on the other. Using these spectral changes, we have plotted a calibration curve for a sufficiently rapid and technically simple quantitative test like sol-particle immunoassay.

We report on the experimental spectra of light scattered at 90 degrees by colloidal gold particles (diameter 30 nm) and aggregates built from these particles during the salt aggregation process. The time dependence of spectra in the range 350-850 nm was measured by using a luminescence attachment to Specord M-40 spectrophotometer. The aggregation of sol was accompanied by essential increasing the single particle spectrum maximum (near 580 nm), its displacement to the red part in the spectrum, and by a broadening of the long wavelength wing of extinction. To explain these findings, we used a computer diffusion-limited cluster-cluster aggregation model. The optical properties of aggregates including light scattering spectra were computed by the coupled dipole method (CDM or DDA). The bulk optical constants of metals were modified by the size-limiting effect of nanoparticles. Our calculations showed a direct correlation between cluster particle number (Nequals10-50) and intensity of scattered light. However, this correlation failed for 100-particle clusters. It can be supposed that DDA model is not adequate for accurate prediction of light scattering properties of large aggregates.

Dynamic mechanical properties of hydrated mucopolysaccharides have been studied in heated solutions by means of molecular hydrodynamic and acoustic techniques. These experiments model the thermal condition used for laser reshaping of cartilage. It has been shown that elastic modulus and internal friction depends on concentration of chondroitine sulphate in the solution and temperature. Maximum of internal friction was revealed at about 40 degree(s)C that corresponds to temperature of breakdown of hydrophobic bonds. Temperature dependence of internal friction manifests structural changes in polysaccharides molecules under laser heating.

The paper presents and proves experimentally a four-stage physical model of laser destruction of biological tissue having absorption coefficient close to 10 cm^-1 and a great skeleton part. Thresholds of bone and liver laser destruction are defined experimentally at wavelengths of YAG:Nd³⁺ and YAG:Ho³⁺ lasers. Correlation of laser radiation energy density to destruction efficiency and invasion factor is studied.

A maximum likelihood estimator for quantifying shifts in speckle patterns resulting from an applied stress to biological tissue is described. The estimator is then applied to calculating the strains and instantaneous strain rates in chicken skeletal muscle subjected to a dynamic acoustic (2 Hz) sinusoidal loading.

We have designed a new optical probe to perform spatially resolved measurements of blood flow and oxygen consumption over an area of about 4 x 4 cm² of the lateral gastrocnemius muscle (calf muscle) of human subjects. The blood flow and the oxygen consumption were measured non- invasively with frequency-domain, near-infrared spectroscopy from the maximum rate of increase of the oxy- and deoxy- hemoglobin concentrations in the muscle during venous occlusion. In a preliminary test on one subject, involving measurements at rest and after exercise, we have found that the spatial variability of the measured blood flow and oxygen consumption is significantly greater than the variability of repeated measurements at a given tissue location. We have also observed a strong spatial dependence of the exercise-induced increase in blood flow and oxygen consumption.

We use the optical/near-infrared (NIR) reflectance spectroscopy to non-invasively measure the hemoglobin saturation in living human skin. The difficulties in clinical application of this technique for skin tissue oxygenation monitoring are due to the complexity of extracting the information of chromophores distribution and their concentrations from the reflectance spectra in case of multiple scattering of light. We have developed a computational model of human skin and Monte Carlo technique for simulation of the reflectance spectra of skin in visible and near-infrared spectral region. The computational model of skin contains several layers with wavy inter-layered boundaries corresponding to the cell structure of human skin. Our model takes into account probe geometry, variations of spatial distribution of blood vessels, various levels of blood oxygen saturation, volume fraction of water, oxy- and deoxy-hemoglobin, melanin content and chromophores of interest. The small source-detector separation (250, 400 and 800 micrometers ) required due to the shallow (100-150 micrometers under skin surface) spatial location of skin capillary loops is of our main interest. Comparison of the results of spectra simulation and experimental results made in vivo are presented. As the experimental system we use the spectrometer mating with the two-dimensional array of CCD camera.

Many diseased states of the brain can result in the displacement of brain tissues and restrict cerebral blood flow, disrupting function in a life-threatening manner. Clinical examples where displacements are observed include venous thromboses, hematomas, strokes, tumors, abscesses, and, particularly, brain edema. For the latter, the brain tissue swells, displacing the cerebral spinal fluid (CSF) layer that surrounds it, eventually pressing itself against the skull. Under such conditions, catheters are often inserted into the brain's ventricles or the subarachnoid space to monitor increased pressure. These are invasive procedures that incur increased risk of infection and consequently are used reluctantly by clinicians. Recent studies in the field of biomedical optics have suggested that the presence or absence of the CSF layer can lead to dramatic changes in NIR signals obtained from diffuse reflectance measurements around the head. In this study, we consider how this sensitivity of NIR signals to CSF might be exploited to non-invasively monitor the onset and resolution of brain edema.

Approximately 5 million people worldwide are blind due to complications from glaucoma, and an estimated 105 million have the disease. Current surgical techniques often fail due to scarring that is associated with disruption of the ocular surface tissues using conventional surgical methods. Demonstrated in the transparent cornea, femtosecond lasers can create a highly precise incision beneath the surface of a tissue. Since sclera is highly scattering with one micron light, the same wavelength used in cornea cannot be focused to the small spot necessary for photodisruption far beneath the surface of sclera. We now demonstrate completely subsurface incisions in human sclera by selecting a laser wavelength that is focusable beneath the surface, namely 1700 nm. Similar techniques may be used in other translucent tissues such as skin. Subsurface femtosecond photodisruption may be a useful for in vivo surgical technique to perform a completely subsurface surgery.

Recent advances in the current state of knowledge about the properties of physiological and synthetic melanin are reviewed in the context of that pigment's optical properties, the physical structure that confers some of its unusual properties, its supportive role in the visual process (by absorbing excess light and reducing intraocular light scatter), its role in some (but not all) laser interactions with ocular tissue, its protective properties (by absorbing potentially phototoxic short-wavelength visible light), and its photoinducible free radical properties. The ability of melanin to form a long-lived radical during visible light irradiation may serve as a protective mechanism against light damage by transforming optical energy into chemical potential energy that can be dissipated in a chain of coupled redox reactions. If a cellular event such as antioxidant depletion occurs that disrupts this chain, however, the melanin radical may promote photo-oxidative damage in ocular tissue. Thus melanin may play two opposing roles in the eye: one protective and the other potentially damaging.

This communication reviews some recent studies on the optical performance of the human eye. Although the retinal image cannot be recorded directly, different objective methods have been developed, which permit to determine optical quality parameters, such as the Point Spread Function (PSF), the Modulation Transfer Function (MTF), the geometrical ray aberrations or the wavefront distortions, in the living human eye. These methods have been applied in both basic and applied research. This includes the measurement of the optical performance of the eye across visual field, the optical quality of eyes with intraocular lens implants, the aberrations induced by LASIK refractive surgery, or the manufacture of customized phase plates to compensate the wavefront aberration in the eye.

In ophthalmology and optometry a number of measures are used for describing quality of human vision such as resolution, visual acuity, contrast sensitivity function, etc. In this paper we will concentrate on the vision quality understood as a resolution of periodic object being a set of equidistant parallel lines of given spacing and direction. The measurement procedure is based on presenting the test to the investigated person and determining the highest spatial frequency he/she can still resolve. In this paper we describe a number of experiments in which we use test tables illuminated with light both coherent and incoherent of different spectral characteristics. Our experiments suggest that while considering incoherent polychromatic illumination the resolution in blue light is substantially worse than in white light. In coherent illumination speckling effect causes worsening of resolution. While using laser light it is easy to generate a sinusoidal interference pattern which can serve as test object. In the paper we compare the results of resolution measurements with test tables and interference fringes.

Optical Coherence tomography is a recently developed imaging technique that has potential to improve the diagnostic limits of the currently available imaging techniques, allowing wide range of clinical disorders to be addressed at an early stage. We report in this paper the application of our OCT system to image soft biological tissues with resolution approaching 9 microns. The tissue targets include biological species, the rat and human G.I. tract tissues. For the G.I. tract tissues, both the normal and pathological specimens, including oesophagus, stomach and colon were imaged. Sharp differentiation of structures and features was observed. The images acquired in this study provide information on tissue microstructure that could only previously be obtained with conventional excisional biopsy.

There are many fields in medicine and biology where optical coherence tomography (OCT) is starting to be used for diagnostics imaging. In our work, OCT imaging has been applied to obtain 3D structure and geometry of mouse aorta and atherosclerotic plaques in it. Differences in plaque formation have been detected between mice fed with cholesterol rich food, and mice kept on special diet. The results of OCT measurements have been confirmed with optical microscopy.

Cancer is the second leading cause of death in the United States. Over 85% of all cancers, such as colorectal, esophageal, bladder, cervical, and oral cancers, originate in the epithelial linings of the body and are readily curable if diagnosed at an early stage. However, many forms of precancerous epithelial lesions are difficult to detect and diagnose using current methods.

Normal OCT images are based on the intensity of reflected and backscattered light as a function of position in the object. However, the light backscattered from the sample contains additional information, e.g. on polarization, velocity, and absorption, which can be used to enhance image contrast and to perform quantitative measurements. In differential phase contrast OCT (DPC-OCT) subwavelength phase retardation variations between transversally adjacent positions are imaged, which are not detectable in normal OCT. In earlier versions of this technique, phase differences were calculated from the amplitudes of the A- scan envelopes recorded by two orthogonal polarization channels in the detection unit, as in polarization sensitive OCT. The drawback of that method was its sensitivity to locally varying reflection coefficients and to scattering. We now present an improved method to analyze the phase difference in DPC-OCT. This method is based on recording the whole interferometric signal rather than only its envelope, and on analyzing its phase function.

Utility and modalities of producing en-face optical coherence tomography (OCT) images of the tissue are discussed. Using a versatile system, transversal and longitudinal OCT images from the retina and skin are presented. Using stacks of transversal OCT images, 3D profiles of the tissue are constructed. The stack of en-face OCT images could also be used to infer longitudinal OCT images. These are compared with the longitudinal OCT images produced with the OCT operating in the hardware longitudinal regime. Once en-face OCT images are produced, they could easier be compared with confocal images as their orientation is similar. Images from the optic nerve are shown generated with the two technologies implemented in a stand-alone system.

A novel phase resolved optical coherence tomographic (OCT) and optical Doppler tomographic (ODT) system is developed for simultaneous imaging of tissue structure and physiology with high imaging speed and high spatial resolution.

The absorption coefficient (mu) _a, the scattering coefficient (mu) _s, and the scattering anisotropy factor g of porcine liver were studied in vitro using the integrating sphere technique and inverse Monte Carlo simulation in the wavelength range 450 to 700 nm. A reference preparation technique was developed using a dermatome providing specimens of 200 to 800 micrometers thickness without pre-freezing the tissue. The optical parameters as measured applying the reference preparation were compared to those measured after cryo-homogenization. We found significant deviations of the scattering coefficient and the anisotropy factor which were compensated when the reduced scattering coefficient (mu) _s' was calculated. We also compared the effects of freezing reference specimens at - 20 degree(s)C and at 77 K without homogenization. For both freezing protocols noticeable deviations were found in all three optical parameters as well as in (mu) _s'. The impact of tissue storage at 4 degree(s)C was measured in the range 4 to 48 hours post mortem and showed a clear reduction of (mu) _a and a significant increase of (mu) _s even after 24 hours of storage. Short time storage of the specimens in saline solution reduced all three optical parameters significantly. In conclusion, the tissue preparation must be controlled in order to provide in vitro optical parameters that sufficiently mimic the in vivo situation.

In this paper we present some of the challenges of studying the spectroscopy of human skin in vivo. The emphasis is in the study of the chromophores that contribute to the clinical appearance of human skin. Information about the chromophores that are of clinical relevance is obtained by spectroscopic studies in the visible part of the electromagnetic spectrum. Such information may be obtained by reflectance spectroscopy or photoacoustic spectroscopy. The challenges that have to be overcome in order to understand the interaction of visible light with skin include the physical state of the chromophores in a strongly scattering medium. A further complication comes from the fact that the chromophores exist in special compartments within the organ and in these compartments they are in high concentrations. The dermis is a strongly scattering medium (optically thick) that is responsible not only for the remitted intensity, it may also alter the color appearance of the organ. The Beer-Lambert law for absorption holds only for dilute solutions and in tissue we almost always have high concentrations. A number of attempts have been made in the past to study and to quantify the chromophores of human skin in the visible through modeling. These have included a number of models such as the Kubelka Munk approach, the diffusion approximation, or the Monte Carlo calculations. All of these make a number of simplifying assumptions which invariably include the deletion of all appendages from the skin.

We conducted visible/near infrared optical measurements on the forearm of human subjects using a commercial diffuse reflectance spectrophotometer, and a breadboard temperature- controlled localized reflectance tissue photometer. Calibration relationships were established between skin reflectance signal and reference blood hemoglobin (Hb) concentration, or hematocrit values (Hct). These were then used to predict Hb and Hct values from optical measurement in a cross validation analysis. Different linear least- squares models for the prediction of Hb and Hct are presented and shows the ability to predict both. It was possible to screen prospective blood donors with low Hb concentration. It was possible to predict anemic subjects in the limited prospective blood donor population.

The results of statistical analysis of Doppler spectra of scattered intensity, obtained from tissues of oral cavity membrane of healthy volunteers, are presented. The dependence of the spectral moments of Doppler signal on cutoff frequency is investigated. Some physiological tests in combination with LDF technique are suggested as a new diagnostic tool. In addition, the results of statistical analysis of Doppler spectra, obtained from tooth pulp of patients, are presented.

We present experimental results on optical properties of the rat skin controlled by administration of osmotically active chemical, such as the 40%-glucose solution. In vivo reflectance and in vitro transmittance spectra of the rat skin were measured. Result of the experimental study of influence of the 40%-glucose solution on reflectance and transmittance spectra of the rat skin are presented. The significant increase of transmittance and decrease of reflectance of the rat skin under action of osmotical agent are demonstrated. The average value of glucose solution diffusion coefficient was estimated as 1.101(DOT)10^-6+/- 0.153(DOT)10^-6 cm²/sec.

In this paper, we described our results of Monte Carlo simulation of light propagation in a multilayered biological tissue, such as skin with blood layer inclusion and optical clearing. This report includes optical clearing simulations with different variants of clearing tissue structure and different effects, which concerned with optical clearing and blood layer inclusion. As well, we described general principles of our algorithms construction.

The original program was developed for biological objects imaging using the data obtained with laser scanning microphotometer. The program might be applied for two- dimension data arrays visualization.

Signal properties of continuous wave (CW) and photon density wave (PDW) detection of absorbing objects in turbid media are presented. The two-component solution of the radiation transport equation is obtained for CW and PDW field of a directed source. The amplitude and phase images of a black spherical object in highly scattering medium obtained by a double-position sensing technique are constructed. Signal to noise ratio for the PDW amplitude and phase and for the CW signal is calculated.

The scattering cross section and asymmetry factor g are important parameters to describe light propagation in turbid media. We present simple approximation for these parameters derived from Mie calculations within wide range of values of the size parameter x and relative refractive index m.

Human leukocytes containing less than 2C DNA per cell (damaged or dead cells) were detected and quantified by flow cytometry and DNA-specific staining with ethidium bromide and mithramycin in whole blood infected with Staphylococcus aureus or Yersinia pestis. Addition of live S. aureus to the blood (100 microbe cells per one leukocyte) resulted in rapid degradation of leukocyte DNA within 3 to 6 hours of incubation at 37 degree(s)C. However, only about 50 percent cells were damaged and the leukocytes with the intact genetic apparatus could be found in the blood for a period up to 24 hours. The leukocyte injury was preceded by an increase of DNA per cell content (as compared to the normal one) that was likely to be connected with the active phagocytosis of S. aureus by granulocytes (2C DNA of diploid phagocytes plus the all bacterial DNA absorbed). In response to the same dose of actively growing (at 37 degree(s)C) virulent Y. pestis cells, no increase in DNA content per cell could be observed in the human blood leukocytes. The process of the leukocyte DNA degradation started after a 6-hour incubation, and between 18 to 24 hours of incubation about 90 percent leukocytes (phagocytes and lymphocytes) lost their specific DNA fluorescence. These results demonstrated a high potential of flow cytometry in comparative analysis in vitro of the leukocyte DNA degradation process in human blood in response to bacteria with various pathogenic properties. They agree with the modern idea of an apoptotic mechanism of immunosuppression in plague.

We have measured differential spectra of water in thin films of Chondroitine sulfate and collagen. After we have calculated a relative quantity of tightly bound water in samples. Percentage of bond water molecules is higher in biopolymer films than in bulk water. It is probably due to formation of water bridges which stabilize the polymer structure.

Experimental study and computer modeling of light propagation in a turbid media with different content of scattering particles were done. Latex phantoms as a model of living tissue have been investigated. Experimental results have shown saturation of transmittance and reflectance at selected wavelengths with concentration. These saturation effects are explained by changes of packing factor of scatterers and should be included in description of living tissue optical property changes due to homeostasis.

The description of the discrete Shifrin's method (DShM) is presented. This method is based on representation of monochromatic Maxwell's equations in integral form. Using a simple discretization scheme the corresponding integral equation is converted to a system of simultaneous algebraic equations which is solved by the successive approximation method. The accuracy and the worked area of the DShM were investigated by comparison with Mie theory for homogeneous sphere. It was shown that this method converges rapidly for optically soft particle, whose equivolumetric radius is of the incident radiation wavelength order. Two normalized scattering matrix elements, S₁₂/S₁₁ and S₃₄/S₁₁, for randomly oriented homogeneous finite cylinders are also presented as a practical example.

The adequacy of simple optical model of three-layer fluorescent phantom of biotissue with optically thick lowest layer has been shown. In the series of samples with varied epithelium thickness, epithelium scatterer concentration, and stromal blood content, the differences between model predictions and recorded fluorescence spectra were reasonably small.

Luminescence analysis, involving electronic recombination of the pyrene molecules, introduced into agar-agar solid-matrix was carried out. For the first time, room temperature phosphorescence (RTP) of pyrene, activated with lead acetate, was observed. It was established that increased lead acetate concentration resulted in weakened luminosity of pyrene excimers and emergence of phosphorescence.

Laser microspectral analysis is an effective method for determination of composition of thin films and evaporations. In the paper results on investigation of accidental superthin evaporations are described. The composition of evaporations allows one to make conclusion about their source.

Tyrosinase is the key enzyme of melanogenesis with unusual enzyme kinetics. Protein kinase C plays an important role in regulating of tyrosinase activity. In the paper the mathematical model of PKC-DAG-dependent signal transduction pathway for UV-radiation is presented.

In the present study some characteristics of lymph microcirculation in mesentery of intact and stressed rats were investigated. The stress was modelled by simultaneous action of rigid immobilization and interrupting sound during 2 h. The direct observation of lymph circulation in microvessels was based on the light intravital videomicroscopy technique. The diameters of microvessels as well as parameters of phasic contractions and valve function of lymphatics were registered. After stress the mean diameter of lymphatic vessels was increased by 13%. The number of microvessels with phasic contractions raised by 20%. The amplitude and frequency of phasic contractions decreased by 31 and 39%, respectively. The percentage of microvessels with lymph flow comprised 86% in control and 93% in stressed animals. The mean velocity of lymph flow increased by 61 micrometers /s whereas the rate of valve work was not modified after stress.

Two-photon correlation spectroscopy enables the deeper insight into the living tissue in comparison to single photon spectroscopy and visualize the biophysical processes occurring there. We present the basic features of an experimental set up based on a research Nikon microscopy and preliminary experimental results of suitable dye with two- photon excitation for pharmacokinetic studies. Despite some technical problems the proposed design differs by its simplicity, requires relatively low-cost optics and has a reasonably low dispersion on the optical elements.

The intravenous glucose tolerance test was performed to estimate the kinetics of blood glucose and insulin levels. Glucose was injected in individual standardized dose (0.5 g. per 1 kg of body weight). Three groups of patients were checked up: 1) patients with coronary heart disease verified by cicatricial alterations in myocardium found by electrocardiographic and echocardiographic methods; 2) children of patients with transmural myocardial infarction practically healthy at the moment of study; 3) persons practically healthy at the moment of study without any indications on cardiovascular diseases and non-insulin dependent diabetes mellitus among all ancestors and relatives who frequently were long-livers. Last groups didn't differ by age and sex. Peripheral blood glucose level, immunoreactive and free insulin (tested by muscular tissue) were studied just before glucose injection (on an empty stomach) and 4 times after it. The received discrete data were approximated by high degree polynomials, the estimation of blood glucose and insulin time functions symmetric was performed. The deceleration of degradation of insulin circulating in peripheral blood and the time decrease of second phase of insulin secretion were analytically established. This fact proves the complicated mechanism of insulin alterations in atherosclerosis, consisting not only of insulin resistance of peripheral tissues but of decrease of plastic processes in insulin- generating cells.

Urological diseases are widespread among the population. Both infectious-inflammatory and oncological diseases are often diagnosed. Modern antibiotics permit to eradicate infectious agent, but efficiency of therapy is insufficient because of reduction of organ function. Thus, besides aetiotropic therapy pathogenetic effect is necessary. Low- intensity laser therapy (LT) is best pathogenetic treatment, so far as it has a few contraindications, low cost and good tolerance. Our goal was to investigate the influence of LT on different aetiology kidney lesion.

The method of ultrasonography is high informative and widely used in diagnostics of ovarian hyperandrogenaemia. The majority of authors consider that a hyperplasia of a stroma is the main pathognomonic marker of polycystic ovaries (PCO). Still recently swell of a stroma was valued visually, that had subjective nature. We offer for the first time a way of diagnostics of stromal hyperplasia grounded on measurement of a volume of a stroma and ovary with ultrasound method, calculation of the ratio of a volume of the ovary to a volume of a stroma for every patient.

The object of the present study is to estimate the impact of transscleral laser cyclocoagulation as a treatment for patients with non-compensated glaucoma and low visual functions. The effectiveness of the given treatment is estimated by the use of multiple statistical methods, including correlation, multiple regression and discriminant analysis. The results meaningfully confirm the effectiveness of laser surgery in non-compensated open-angle (stage III) glaucoma treatment, whilst the developed mathematical model of correlation between intra-eye liquid production and key operation parameters can be successfully used to control the process of liquid production.

The work is dedicated to problems of diagnostic oncologic diseases by a spectroscopic-optical method and is prolongation of long-term examinations held earlier by Vovk S.M, Naumov S.A. and Pushkarev S.V. The actual spectra of a diffuse reflection removed in vivo and in vitro are given, is angry- and good-quality neoplasms, healthy tissue and blood of breast and other organs. Problems of a clinical oncology are in a center of attention in medicine because the cases of disease malignant swellings increase, which is stipulated by an irregularity of present methods of diagnostic.

Subcellular structures are mainly responsible for light scattering in tissue. Since these structures change their outer shape during hypoxia, backscattered light intensity should be useful in monitoring of tissue in hypoxic or ischemic situations. In a new model of isolated perfused pig heart we investigated the relation between three-dimensional functional structures caused by tissue light scattering and the perfusion pressure during reoxygenation after hypoxia. By use of EMPHO-Oxyscan we could see that there is a clear relation between the perfusion pressure and the level of 3D structures. At very low perfusion pressures there is a delay in recovery of myocardium. Increase in perfusion pressure accelerates the recovery. With functional 3D images created by use of EMPHO-Oxyscan, we now have an instrument for depicting these processes. This technique will be useful in clinical monitoring in cardiac surgery, intraoperative as well as postoperative.

The concept of refractive index matching used for the enhancement of optical penetration depth of the whole blood is discussed on the basis of in vitro studies. It was stated that blood optical clearing is defined not only by refractive index matching effect, but also by changes of RBC size and their aggregation ability when chemicals are added. For example, for whole blood twice diluted by a saline adding of 6.5% of glycerol reduces the total attenuation coefficient from 4.2 mm^-1 to 2.0 mm^-1, and correspondingly increases substantially the optical penetration up to 117%. For other tested agents (three types of dextrans A, B, and C; propylene glycol; and trazograph, all at concentration 6.5%) the enhancement of penetration was from 20.5% (for low molecular dextran) up to 77.2% for propylene glycol. For non-diluted blood such effects were not very pronounced, but still glycerol at 13% has the highest enhancement up to 52% and the total attenuation coefficient was changed from 6.1 to 5.1 mm^-1.

Statistical analysis of images of time-integrated dynamic speckle patterns is considered as the tool for diagnostics and imaging of in vivo tissue dynamics such as blood microcirculation in superficial layers of human tissues and organs. Basic approach for blood microcirculation monitoring using the contrast analysis of time-averaged speckle images is known as LASCA (Laser Speckle Contrast Analysis) technique. This paper presents the modified version of LASCA, which is based on application of the localized probe light source and the spatial filtration of analyzed speckle pattern in the object plane. Being compared with classical LASCA technique, this method has the certain disadvantage as the necessity of scanning procedure to provide the reconstruction of maps of blood microcirculation parameters, but it gives the additional possibilities for the analysis of depth distributions of these parameters. Theoretical background for the depth-resolved analysis of blood microcirculation parameters on the basis of the concept of effective optical paths distributions for multiple scattered probe light is considered.

New method of monitoring of blood microcirculation in orthodontics is suggested. Influence of own noise of measuring system on formation of speckle-interferometric signal is studied.

A method of biologic fluids flows in thin capillaries flow direction and velocity determination using statistical properties of speckles is proposed. Two point detection of scattered light intensity fluctuations allows for slow flows velocity measuring and flow direction determination without incident beam frequency shifting and with using one focused incident beam.

Endothelial cells outline the blood vessel wall and contribute pivotally to the regulation of numerous microvascular characteristics such as permeability, vascular tone, vasomotion, or cell-cell interactions. These functions are mediated by second messenger responses and intracellular signal transduction cascades within the endothelial cells. Imaging of endothelial cellular and subcellular responses has yet been limited to studies in isolated or cultured cells, which cannot reflect dynamic physiologic or pathologic cellular interactions in the intact microcirculation. Combining micropuncture and microcatheter approaches with in vitro fluorescence imaging techniques, we have developed methods for imaging endothelial cellular responses of intact pulmonary microvessels in situ.

OPS-imaging is a novel technique which can be used to obtain images of the microcirculation using reflected light. High contrast transillumination quality images can be collected not only from thin tissues, but from the surface of solid organs as well. In OPS-imaging the tissue is illuminated with light that has been linearly polarized in one plane. The light is then both scattered and reflected by the tissue. In front of the camera there is a second polarizer which is oriented in a plane precisely orthogonal to that of the illuminating light. This means that light which is directly reflected by the tissue, which maintains its polarization, is rejected by the polarizer in front of the camera. The only light which enters the camera and forms the image is light which has become depolarized, which typically requires at least 10 scattering events. Thus, the light which forms the image comes from deep (0.5 mm) within the tissue and effectively back-illuminates the absorbing material in the foreground. When the light has a wavelength within the hemoglobin absorption spectrum (548 nm), the scattered light is absorbed by the hemoglobin in the red cells, making it possible to visualize the blood vessels as in transillumination intravital microscopy. Thus, images of the microcirculation of solid organs can be obtained without the use of fluorescent dyes. OPS-imaging has been incorporated into a small, hand held device which is easily transportable (CYTOSCAN). Because of these two advantages, it is possible to not only use OPS-imaging in the laboratory, but also in the clinic on patients.

Only few techniques that could provide real-time continuous multiparametric physiological data have been developed. Therefore, experimental and clinical monitoring devices for organ and tissue viability evaluation are still lacking. In this study, we present the new concept of tissue vitality defined as a product of a few parameters monitored in real- time by a combined measurement of tissue blood flow and volume as well as the oxidation reduction state of the mitochondria. The hypothesis behind the new approach is that in order to evaluate in real-time tissue vitality, it is necessary to monitor both microcirculatory blood flow and volume as well as the intracellular O₂ balance as reflected in the mitochondrial redox state.

Living tissue of mammals contains a large amount of subcellular particles like mitochondria that are involved in light scattering. Since these particles correlate in a certain way with the functional status of cells, light scattering may be useful for monitoring of functional tissue state. With EMPHO SSK Oxyscan we investigated functional parameters in a new kind of isolated perfused pig heart model. In this perfusion model we use organs obtained from the abattoir that are reperfused by use of a heart-lung machine. By creating 3D images of tissue light scattering we found an interesting relation between morphological structures of myocardium and the patterns of the 3D images. Additionally, we created 3D images of myoglobin oxygenation. Furthermore, we got spectra showing the redox state of cytochromes. We believe that this new kind of tissue imaging method will give us the opportunity to get new insights into myocardial function.

A range of acute skin reactions, ranging from mild erythema to moist desquamation, can be seen in patients receiving standard fractionated radiotherapy to the breast for conservation therapy of breast carcinoma. In a number of cases these reactions can cause considerable discomfort and seriously affect the patient's quality of life. In previous studies we have used the techniques of laser Doppler imaging, digital thermographic imaging and lightguide spectrophotometry to study oxygen supply and blood flow in inflammatory reactions induced experimentally in forearm skin. The present study is an attempt to use the same techniques to investigate whether any or all of them can detect changes in breast skin very early on in the course of radiotherapy treatment. A further aim of the longer term study is to investigate to what extent these early changes may be able to predict the occurrence later of severe acute or delayed reactions.

The main signals of light coming back from tissues result from multiple scattering interactions of the incoming light wave with the multipoles of subcellular particles. For a detailed knowledge of the systems, noninvasive optical measurement techniques in the microvolume (capillary, cellular and subcellular signals) are well established at the Institute of Physiology. Due to these methods, the scattering signals and their changes can be detected and analyzed quantitatively at the micrometers ³ volume. The scattering parameters of interest can be set separately and the results can be visualized by three dimensional imaging techniques. Mitochondria produce different scattering patterns by a change of their respiratory state due to different sizes. The algorism presented simulates this scattering. It allows fast predictions of effects like variation of particle size, variation of concentration and absorption at different geometries of lightguides. A comparison of the simulation with the measurements in microvolume shows correlation so that the algorism is reliable for qualitative and quantitative explanation of what happens in the tissue. A remarkable effect is that there are no big differences between measurements in 360- degree direction and 90 degrees because of massive multiple scattering effects.

In organs we can find signal changes between vascular and parenchymal cells. We started to combine spectral measurements by the use of merocyanine in isolated perfused rat liver to analyze the alterations of dc-potentials. There have been first experiments with Merocyanine (M-540) in the seventies with stained axons and hearts to measure optical action potentials (Morad, Salama, et al, 1978). It is reported that the increase of fluorescence response is connected to a depolarization and its decrease to a repolarization. Tissue imaging after staining with this dye should be ideal for a long term interpretation of dc-potential alterations as an analysis of the electrical coupling in different cell types under various experimental conditions like anoxia or temperature changes.

In this paper we investigated the lymph flow and other parameters of lymph microcirculation in vivo. The analysis of lymphatic functions in norm and at the topical application of N-nitro-L-arginin (L-NNA, 10^-4M), dimethylsulfoxide (DMSO, 30%) was performed. We observed lymph microvessels of rat mesentery with diameter from 50 to 270 micrometers . The lymph flow velocity was determined by the biomicroscopic (V) and speckle-interferometrical (M₁) methods. L-NNA and DMSO led to different effects on diameters of lymphatics. L-NNA as well as DMSO stimulated the phasic activity and lymph flow in microvessels of rat mesentery. We suggested that used vasoactive drugs stimulated lymph pumping by different ways.

The interest to the non-invasive study of capillary blood flow in cardiological and diabetes patients is raised mainly by the explicit microcirculation disorder in such pathological patients. The interest to quantitative microcirculation parameters in the recent years has promoted the development of new technical facilities. In 1997, the Centre for Analysis of Substances in collaboration with a design team of the Space Device-Making Institute developed the computerized capillaroscope. This device consists of a high-resolution microscope with a magnification of up to 1000 and a color CCD camera that sends the image to a PC- based video processing station. An important merit of the instrument is the possibility of conducting non-invasive investigations, i.e. without damage to the skin or vessels and not causing any pain or unpleasant sensations. The sophisticated software provides for the possibility of accurately measuring capillary blood velocity as well as the size of the perivascular zone.

An all-solid-state sub-40-fs self-starting Cr⁴⁺:forsterite laser with a wavelength tunable within the range of 1.21-1.29 micrometers adapted in its power, temporal, and spectral parameters for high-resolution optical coherence tomography (OCT) and nonlinear optical tissue imaging is presented. Stable self-starting mode locking in the created laser is achieved both with and without semiconductor saturable-absorber mirrors, while the double-pulse regime of lasing permits time-resolved measurements on biological systems to be performed. Frequency doubling is implemented through second harmonic generation in a 2.5-mm-long DCDA crystal, ensuring group velocity matching for femtosecond pulses produced by the Cr:forsterite laser. A set of holey fibers with a period of the photonic crystal structure of the cladding ranging from 468 nm to 32 micrometers ensure the tunability of the photonic band gap of the cladding within a broad spectral range, providing different waveguiding regimes for Cr⁴⁺:forsterite laser radiation.

The possibility of laser overheating of tumors in comparison with normal tissues at the same laser actions was explained by means of computer calculations. This effect of overheating of tumors was called selectivity of laser actions on the tumors. The experiments on the experimental animals gave the results which were in a good agreement (qualitatively) with our calculations. These computer calculations of tissues heating can be used for photodynamic therapy and laser therapy also.

For many years the Institute on Laser and Information Technologies RAN has been developing a concept of high-power industrial CO₂ lasers with diffusion cooling of the working medium. The paper gives a description of the laser medical system Iguana for transmyocardial laser revascularization (TMLR) as an example of various applications of high-power waveguide CO₂ lasers. The clinical results of the TMLR method application in surgical treatment are presented. The methods of determination of the time, when the laser beam passes through the demarcation line between myocardium tissue and blood, are discussed.

The influence of low power laser radiation on arterial blood oxygen saturation has been investigated. It is shown that the influence of a laser radiation causes a local decrease of saturation, which is probably due to the photodissociation of oxyhemoglobin. The value of saturation decrease depends on radiation power and spectral composition.

Experimental investigations of light scattering in milk polluted by salts of metals are presented. The phenomena of luminescence and quenching of luminescence by impurities are found. These results can be used for instrumental express analysis of toxins in milk by modified laser device 'MIG' which had been constructed for monitoring composition of milk. Application of laser for express diagnostic of toxins in liquid biological systems is discussed.

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.

Kinetics of laser induced phosphorescence of singlet molecular oxygen was measured with nanosecond resolution at 1270 nm in air-saturated aqueous solutions of tetrakis(4- sulfonatophenyl)porphine, tetra sodium salt (TPPS). The phosphorescence kinetic curve comprised the rise and decay phases that are well described by exponentials with the rise time constant, (tau) _r equals 2.16 +/- 0.08 microsecond(s) and decay time constant, (tau) _d equals 3.15 +/- 0.15 microsecond(s) , the rise corresponding to the kinetics of energy transfer from triplet porphyrin to molecular oxygen, the decay - to deactivation of singlet oxygen. Within the accuracy of our measurements both (tau) _r and (tau) _d did not depend on pH in the range 5.8-9, laser powers in the range 0.32-1.6 W/cm², the porphyrin concentrations in the range 13-48 (mu) M and the presence of phosphate buffer saline.

Light scattering in living tissues is mainly caused by subcellular particles like mitochondria. The size of mitochondria changes according to differences in the functional status. Therefore light scattering should be a useful technique for monitoring the functional state in tissues. We investigated functional parameters in our model of the isolated perfused rat liver. For the measurements of light scattering we used the EMPHO SSK Oxyscan. Backscattered light from tissue is shown in 3D images. We found an interesting relation between structures of the liver and the patterns of the relating 3D images. In addition, our underlying spectra show the redox state of cytochromes. This new method of tissue imaging should give the opportunity of new insights into liver function.