We have evaluated the results of clinical and morphological study of microcirculation and its intravascular factors in 120 patients with chronic obstructive pulmonary diseases (COPD). Conjunctival biomicroscopy with quantitative evaluation of microcirculatory changes we performed. This data were compared with the results of laboratory study of erythrocytes and thrombocytes aggregation, some plasma hemostasis indices and morphological examination of microcirculation. The results of conjunctival biomicroscopy showed the close correlation between the clinical severity of the disease, the degree of respiratory failure and the degree of microcirculatory disorders. Progress of the disease with the development of respiratory failure and cor pulmonale was characterized by the expansion of the process of erythrocytes aggregation to the whole parts of the microcirculatory bad and was associated with perivascular hemorrhages. In some patients with severe COPD laboratory data showed chronic disseminated intravascular microcoagulation (DVS-syndrome). Intravascular platelets, erythrocytes and mixed aggregates which completely cork the vessels and compressed endothelium were uncovered by electron microscopy. Platelets membrane injuring with its degranulation was seen. This discovered correlation between microcirculatory abnormalities in lungs and in conjunctiva in patients with COPD demonstrate that this abnormalities of microcirculation are prevalent. This allows to use in clinical accessible and informative method of conjunctival biomicroscopy to estimate the condition of microcirculation in this pathology.

We report on the results of a collaborative effort made in the field of optical diagnostics of whole blood samples to study the ability of red blood cells to aggregate in a Couette chamber. We studied a possibility to quantitatively measure this ability as a function of the physiological state of blood donors. The aggregometer designed by the Russian coauthors of this paper and described in their earlier publications (see e.g. Proc SPIE 1884, 2100, 2678, 2982) was extensively used in the experiments performed in the Rheumatology Institute in Moscow and in the Charite Clinic in Berlin. The following parameters were measured: two characteristic times of RBC aggregation and the average spontaneous aggregation rate in the state of stasis, the average hydrodynamic strength of all aggregates and that of the largest aggregates. Different algorithms of the remission signal processing for the quantitative evaluation of the above parameters were compared. Reproducible alterations of the parameters from their normal values were obtained for blood samples from individuals suffering auto-immune disease and diabetes. Statistical data is reported proving high efficiency of the technique for the diagnostics of rheological disorders. Basing on these data the quantitative criteria of the heaviness of hemorheological state of the patients are proposed that are important for choosing specific therapies for which the patient is minimally resistant.

Native fluorescence characteristics of blood plasma was studied in the visible region, during the regenerating phase of the rat liver tissue. Animals were subjected to partial hepatectomy (PH). Blood samples were collected after several intervals of post PH time and also from control animals. Native fluorescence spectra of blood plasma were measured at 405 nm excitation. In addition to the primary emission peak around 440 nm, the fluorescence spectra of experimental group of animals showed distinct secondary emission peak around 620 nm, which is found to be absent in the case of control animals. This may be attributed to the presence of endogenous porphyrins. The fluorescence intensity at 620 nm was found to be maximum at about 16 hrs of post PH time and it decreased thereafter with increasing post PH time. The spectral differences between controls and experimental animals were found to be minimal at 240 hrs of post PH time.

Fluorescence spectroscopy of intrinsic biomolecules has been extensively used in biology and medicine for the past several decades. In the present study, we report the native fluorescence characteristics of blood plasma from normal human subjects and patients with different liver abnormalities such as hepatitis, leptospirosis, jaundice, cirrhosis and liver cell failure. Native fluorescence spectra of blood plasma -- acetone extract were measured at 405 nm excitation. The average spectrum of normal blood plasma has a prominent emission peak around 464 nm whereas in the case of liver diseased subjects, the primary peak is red shifted with respect to normal. In addition, liver diseased cases show distinct secondary emission peak around 615 nm, which may be attributed to the presence of endogenous porphyrins. The red shift of the prominent emission peak with respect to normal is found to be maximum for hepatitis and minimum for cirrhosis whereas the secondary emission peak around 615 nm was found to be more prominent in the case of cirrhosis than the rest. The ratio parameter I₄₆₅/I₆₁₅ is found to be statistically significant (p less than 0.001) in discriminating liver abnormalities from normal.

Noninvasive blood glucose monitoring is the aim of research activities concerning the detection of small glucose concentrations dissolved in water and blood plasma. One approach for these measurements is the exploitation of absorption bands in the near infrared. However, the strong absorption of water represents a major difficulty. Transmission measurements of glucose dissolved in water and in blood plasma in the spectral region around 1600 nm with one- beam spectrometers and a FT-IR spectrometer are discussed. The evaluation of the data is carried out using a two-layer Lambert-Beer model and neural networks. In order to reduce the dimensions of a potential measuring device, an integrated acousto-optic tunable filter (AOTF) with an Erbium doped fiber amplifier as a radiation source is used. The fiber optic components are examined concerning their suitability. The smallest concentrations of glucose dissolved in water that can be separated are approximately 50 mg/dl. In the range of 50 mg/dl to 1000 mg/dl a correlation coefficient of 0.98 between real and estimated glucose concentrations is achieved using neural networks. In blood plasma so far glucose concentrations of about 100 mg/dl can be distinguished with good accuracy.

The method and device for non-invasive measurement of blood glucose concentration based on the diffuse reflectance from the transcutaneous layers is proposed. Original normalizing ratio algorithm permitting to separate glucose absorption from absorption of other blood components is suggested. It was shown that the influence of water and some other components such as hemoglobin, albumin, globulin's and cholesterol concentration variations to the estimation of the glucose concentration can be compensated using spectral analysis of the reflection on several specially selected wavelengths and proposed algorithm. Device with optical geometry minimizing the effects of changes in the scattering background of biological tissues was developed. NIR spectral range 800 - 1800 nm was used because of its good transparency for biological tissue and presence of glucose absorption band. We used two kinds of light sources, namely LED array and Xe flash lamp. Tissue phantoms (different glucose concentration (0 - 1000 mg/dl) solutions with polystyrene beads or with milk) were used as samples. Scattering and absorption contribution to the dependence of diffuse reflection on glucose concentration was experimentally verified.

An invasive in vivo fluorescence detection scheme was employed to continuously monitor exogenous dye clearance from the vasculature. This invasive physiological monitoring technique was successfully demonstrated in a rabbit model. A commercially available catheter with embedded fiber optics was employed to transmit the excitation light and detect the emitted fluorescence. The clearance of indocyanine green, known to be exclusively cleared from the blood stream by the liver, was determined invasively. The clearance curves determined by this novel invasive method replicated the clearance curves in the same animals employing the non- invasive method established previously. Thus, the feasibility of a new invasive method for physiological function assessment was established.

Distilled water possesses weak luminescence in the near UV and visible regions of the spectrum. Trace amounts of both luminescent and non-luminescent substances stimulate the emission of luminescence at both wavelengths 360 and 410 nm. The intensity of the 'short-wave' band in pure water is approximately ten times less, than the corresponding intensity in aqueous solution of glycyltryptophan with concentration about 0.006 mg/ml while the intensity of the'long-wave' band in pure water is only twice less than in the solution. Optical properties of stored samples of water and glycyltryptophan solutions change spontaneously during several days after preparation. These changes may be of monotonous and nonmonotonous (even oscillatory) character. Finally the system comes to a stable state which can either coincide with the initial state or differs from it. Changes in luminescent features under the influence of weak UV and X-ray radiation are also observed. The effect of external fields depends greatly on the phase state of solution, according to the spontaneous dynamics of solution, being the highest at non- equilibrium state. The duration and complexity of evolution of the luminescence spectra confirm the idea that water and aqueous solutions should be considered as non-equilibrium systems capable to self-organization.

This paper experimentally studies the diffuse reflectance spectra of blood in cylindrical glass vessels embedded in the Intralipid solution as a skin tissue phantom. The measured spectra were mainly governed by the absorption characteristics of a small amount of blood added into the medium, but were also slightly influenced by the vessel diameter, depth from the surface, and oxygen saturation state. To extract useful information on these conditions from the spectra, we propose use of the color perception on the basis of the pseudo- reference white, and verify its usefulness. The result can also be used to explain the bluish color of veins in the skin tissue.

An improved version of our laser Doppler tester has been developed. The tester contains a tissue phantom made in the form of a thin film. Films with a thickness in the range 20 - 90 micrometer are stacked to reach a total thickness of several millimeters. Motion is realized by rotating discs with a thickness of 20 - 22 micrometer, separated by a static layer of 95 micrometer thickness. The total number of movable layers is 13. The tester contains four phantom stacks, each mimicking a different type of tissue. Since each tissue consists of a stack of thin layers separated by a matching medium, the consequence of a possible mismatch on the photon penetration depth is investigated with the Monte Carlo simulation technique. This leads to a range of refractive indices in which the matching medium must be taken to keep the effect of mismatch below an acceptable level. It appears that for a tissue structure composed of layers with a thickness of 30 micrometer, the refractive index of the matching material should be between 1.50 and 1.54 for a refractive index of the matrix material of the phantom equal to 1.52. Within this range, the effect of mismatch on the probed depth and the total reflection is limited to 2%.

The dynamic light scattering has been a powerful tool in measuring the size of a cluster produced by particle aggregation. This technique can be applied to only tenuous or diluted media since it has been developed on the basis of the single scattering theory. In the recent years, in situ monitoring of the aggregation process in dense scattering media has been needed in the biological diagnostics and chemical industry. We investigate a temporal autocorrelation function of light scattered multiply from aggregated particles in dense colloidal suspensions. In the experiments, the particle distribution was controlled by adding the NaCl solution to the colloidal suspension of polystyrene latex beads at 10% volume fraction. It is shown that the temporal autocorrelation function is composed from the contributions of single and multiple scatterings of light. The relaxation time of the temporal autocorrelation function increases as the aggregation of particles progresses and, therefore, its variation is related with the growth of clusters. Moreover, we estimate the number of particles included inside one cluster using the decreasing rate of the temporal autocorrelation function of the single or the multiply scattered light. As a result, the components of single and multiple scatterings of light are available for the measurements of the clusters composed from a few particles and of many particles, respectively.

We show that the optical properties of a sample with moderate scatter can be obtained by performing frequency domain measurements in a reflection geometry. In experiments and Monte Carlo simulations we show that absorption and scatter produce opposing trends in the amplitude signal and common trends in the phase signal. Therefore a measured amplitude and phase signal correspond to a unique combination of optical properties for a given phase function.

We have developed Intracavity Laser Refractometry in Reflection (ILRR) method which is perspective for research of liquid biological media. It is based on the control of the laser spectrum. Fast-action and sensitivity of ILRR method correspond to the best results in optical measurements. ILRR method was used for determination of blood refractive index values of healthy and sick persons. The refractive index correlates with the course of the disease. It can serve objective parameter for an estimation of a level of inflammatory processes on organism. We have investigated photoresponse of the blood to low-level laser irradiation. Photoresponse starts just after the turning on red He-Ne therapeutic laser beam. After several dozens milliseconds there is a saturation. At the same time weak thermal effect produces small and slow influence on the refractive index behavior. It can be supposed that fast part of the photoresponse corresponds to the start of biochemical processes. The investigations of photoresponse of plasma leukocytes and erythrocytes showed that the erythrocytes are main photoreceptors of red light on cellular level. Hemoglobin is responsible for the fast photoresponse on molecular level. The refractive index behavior in real time allows to evaluate maximum therapeutic dose on organism, cellular, and molecular levels.

Features of the speckle patterns formation due to the laser light propagation in multiple scattering systems which influence on the accuracy of measurement of the scattering system dynamic parameters by means of statistical analysis of the time-averaged spatial speckle intensity fluctuations have been studied experimentally. Two different experimental techniques have been used: photon correlation spectroscopy and contrast analysis for time-averaged speckle patterns similar to LASCA method. Results of in-vivo experiments as well as experiments with model scattering media (water solution of Intralipid) are presented. Recommendations about the choose of appropriate data processing algorithms as well as about calibration technique for time-averaged speckle technique are discussed.

In our investigation, we present both multi-spectral in vitro and preliminary single wavelength in vivo results supporting the use of optical polarimetry as a potential non-invasive method for glucose sensing. The site utilized for our in vivo measurements is the anterior chamber of the eye in a rabbit model. The anterior chamber of the eye contains a relatively clear and minimal scattering fluid known as the aqueous humor. The glucose levels of the aqueous humor are correlated to those of blood, therefore providing a mechanism to indirectly estimate blood glucose levels. A device to effectively couple light through the anterior chamber is also presented. As for the in vitro experiments, a multi-spectral approach is demonstrated as a method to minimize prediction error when glucose is not the only optically active component that varies in concentration.

Fluorescent chemical sensors are being developed for in vivo use in quantification of important physiological species. Design of an optical probe for delivery of excitation radiation and collection of light emitted from subcutaneous fluorescent sensors is a critical step in developing reliable measurement methods. This paper outlines the use of Monte Carlo simulations of light propagation in estimating the radial distribution of light emitted from the sensor as well as tissue fluorescence. A discussion of how the results of such models can be used to optimize probe geometry for maximum signal-to-noise is presented. Sensitivity of the simulation to layer thickness, tissue optical properties, and sensor composition are detailed. Simulation output is also compared with experimental results and progress in development of one potential sensor system is presented.

Wavelength selection is an important preprocessing step for improving and simplifying calibrations in both quantitative and qualitative problems. An improved variable selection algorithm has been developed to improve upon existing methods in terms of speed and prediction error. The new technique uses a novel peak-hopping strategy to move quickly between important spectral regions. Results when applied to both Raman and near-infrared data show that the algorithm is very fast, decreases prediction errors, and chooses a small subset of the full spectral range available. A comparison with other techniques is given and the respective advantages and disadvantages are discussed.

Optical monitoring of blood gas concentrations is achieved using sub microliter quantities of a colorimetric indicator continuously perfused through microdialysis hollow fiber membranes in blood contact. The hollow fiber membranes, selected based on their permeabilities in blood, are silicone for both oxygen and carbon dioxide sensing, and cuproammonium rayon for pH sensing. A sweep fluid passed through the lumen of these fibers undergoes a diffusive equilibrium with the blood and then is continuously mixed with an indicator. A 450 nm gallium nitride LED is used to excite an oxygen-sensitive fluorophore, ruthenium tris-(2,2'-bipyridyl) II dichloride, which has a 620 nm emission peak that is analyzed with an orange coated photodetector. Gallium phosphide 555 nm LEDs are used to excite the 550 nm absorbance peak of phenol red for pH measurement and phenol red in a 35 mM bicarbonate buffer for CO₂ measurement. Accurate measurement of small absorbance and fluorescence changes using small bore capillary tubes allows good resolution of biochemical concentrations. Continuous replenishment of the indicator by flow lends itself to a stable method of biochemical analysis that has potential for long term performance. In vitro buffer studies demonstrate a resolution of plus or minus 0.5 mmHg for pCO₂, a plus or minus 1.5 mmHg for pO₂, and a plus or minus 0.003 pH.

The 'CHAKRA's, which is a sanskrit word transliterated into English means circles, is usually referred to the nodal points of energy or awareness in the human body. In spite of the extensive literature available on this subject, it is still steeped in myth and suspect in the eyes of modern science. In this presentation an attempt is made to outline the neurological and physiological significance of chakras on a rational basis so that it can be acceptable to medical practitioners. Proper understanding of the significance of chakras can possibly help modern psychiatrists in dealing with human beings having psychological problems. In the present investigations the results obtained on the activation of 'Chakra's as monitored with the help of optical sensors are presented. A suitable subject who is familiar with 'Chakra's has been chosen for the present study. Data is also obtained simultaneously with the help of other sensing elements like temperature sensors which help in monitoring the differential breathing through the two nostrils of the subject. The emergence of approximately 8 cycles per minute (0.13 Hz) rhythm has been noticed in PPG signals from the Ajna chakra located on the forehead. An attempt is made to understand the neurological and physiological significance of these rhythms and other associated phenomena seemingly originating from the activation of 'Chakra's.

We studied the enzyme acetylcholinesterase (AChE) that catalyses the hydrolysis of acetylcholine (ACh) -- cell neuromediator. After transfer of excitation ACh must be removed from the synaptic cleft in hundreds of microseconds. This is accomplished by removing of acetate (A) and choline (Ch) that are the products of 'cutting' of ACh by AChE. High activity of the enzyme is related with the large dipole moment of AChE that attracts positively charged molecules of ACh into active site (AS) and also with the fast removing of the reaction products from AS. One of the hypothesis accounting for the fast removing of A and Ch from the AS pocket presumes the existence of a 'back door' that allows them to leave the pocket without interference with the molecules of ACh that penetrate inside the AS. We made an attempt of verification of the 'back door' hypothesis by means of computational experiment for 2D and 3D spaces. We considered the problem of penetration of ACh and exit of the negatively charged A and positively charged Ch under the conditions of fluctuating potential relief of the AChE AS. For the laser spectroscopy we pose two problems: (a) determination of the dipole moment of AChE in the case this molecule is surrounded by ACh molecules by means of the electro-optical method and (b) detection of AS conformations related with functioning of the 'back door' (the ring-system of Trp⁸⁴). We report on Raman spectroscopy study of the influence of crown-esters on amino groups.

This report describes the evaluation of a noninvasive laser Doppler system comprising a sensor, a digital signal processor (DSP) unit and a visualizing PC for continuous blood flow measurements. The first weighted moment of the power spectrum density of the laser Doppler sensor signal is a linear measure for blood flow. In order to estimate the power spectrum densities in real time, a first order autoregressive process model was developed. Due to this very fast signal processing, the system allows measurements both in microcirculation and of higher blood flows in larger vessels with a signal bandwidth of up to 200 kHz, e.g. in superficial arteries. Since the analytical dependency of blood flow and first spectral moment is only valid for tissue perfusion, Monte Carlo simulations were performed to evaluate this dependency also for higher blood flow velocities in larger vessels. A multilayered, semi- infinite tissue model essentially comprising epidermis, dermis and a blood vessel with a parabolic profile of constant blood flow was used varying different parameter like vessel diameter and skin thickness. Furthermore, model measurements were performed using a Delrine slab with a drilling through which constant flow of whole blood was provided. Both the Monte Carlo simulations and model measurements prove very high linear correlations between the calculated spectral moments and flow velocities.

The effect of anomalous optical behavior of biological tissue at high-intensity laser irradiation can be caused by heat- induced changes in optical properties of consisting components, mainly muscle tissue and blood. We registered the spectral transmission of fresh human whole blood and serum samples in the wavelength range of 300 - 700 nm at the heating of samples in the temperature range of 35 - 65 degrees Celsius. The results showed an increase of 10 - 15% in the transmission of blood serum at the temperature rising up to 50 - 60 degrees Celsius. In the case of diluted whole blood a sharply enhanced transmission was observed at the temperature of 56 - 60 degrees Celsius, while further heating resulted in a decreased transmission down to the initial level. The significant changes (of a three orders of magnitude) in the transmission of whole blood at the wavelength of Nd:YAG laser (1064 nm) were observed. The obtained results can be considered as one of the possible explanations of the anomalous light distribution in certain tissues.

The work is devoted to the theoretical investigation of the formation of a radiation scattered by optically soft spherical biological particles into the solid angle (Theta) _o (integral indicatrix). Integral light-scattering indicatrix F in the range of the phase-shift parameter (Delta) from 0.01 to 80 and of the relative refractive index m (m equals n + i_(chi )): n less than or equal to 1.2; (chi) less than or equal to 10^-2 has been studied. Fraunhofer diffraction, geometric optics, Wentzel-Kramers-Brillouin approximation, the Mie theory have been applied for the analyses of the light- scattering indicatrix. The theoretical and numerical investigation reveals that the integral light-scattering indicatrix can be represented as a combination of two mechanisms, namely, Fraunhofer diffraction and geometrical optics ((Delta) greater than or equal to 3). The feasibility of determining the relative refractive index of the studied biological particles has been shown.